fs/btrfs/extent-tree.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18 #include <linux/sched.h>
  19 #include <linux/sched/signal.h>
  20 #include <linux/pagemap.h>
  21 #include <linux/writeback.h>
  22 #include <linux/blkdev.h>
  23 #include <linux/sort.h>
  24 #include <linux/rcupdate.h>
  25 #include <linux/kthread.h>
  26 #include <linux/slab.h>
  27 #include <linux/ratelimit.h>
  28 #include <linux/percpu_counter.h>
  29 #include "hash.h"
  30 #include "tree-log.h"
  31 #include "disk-io.h"
  32 #include "print-tree.h"
  33 #include "volumes.h"
  34 #include "raid56.h"
  35 #include "locking.h"
  36 #include "free-space-cache.h"
  37 #include "free-space-tree.h"
  38 #include "math.h"
  39 #include "sysfs.h"
  40 #include "qgroup.h"
  41
  42 #undef SCRAMBLE_DELAYED_REFS
  43
  44 /*
  45  * control flags for do_chunk_alloc's force field
  46  * CHUNK_ALLOC_NO_FORCE means to only allocate a chunk
  47  * if we really need one.
  48  *
  49  * CHUNK_ALLOC_LIMITED means to only try and allocate one
  50  * if we have very few chunks already allocated.  This is
  51  * used as part of the clustering code to help make sure
  52  * we have a good pool of storage to cluster in, without
  53  * filling the FS with empty chunks
  54  *
  55  * CHUNK_ALLOC_FORCE means it must try to allocate one
  56  *
  57  */
  58 enum {
  59         CHUNK_ALLOC_NO_FORCE = 0,
  60         CHUNK_ALLOC_LIMITED = 1,
  61         CHUNK_ALLOC_FORCE = 2,
  62 };
  63
  64 static int update_block_group(struct btrfs_trans_handle *trans,
  65                               struct btrfs_fs_info *fs_info, u64 bytenr,
  66                               u64 num_bytes, int alloc);
  67 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  68                                struct btrfs_fs_info *fs_info,
  69                                 struct btrfs_delayed_ref_node *node, u64 parent,
  70                                 u64 root_objectid, u64 owner_objectid,
  71                                 u64 owner_offset, int refs_to_drop,
  72                                 struct btrfs_delayed_extent_op *extra_op);
  73 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  74                                     struct extent_buffer *leaf,
  75                                     struct btrfs_extent_item *ei);
  76 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  77                                       struct btrfs_fs_info *fs_info,
  78                                       u64 parent, u64 root_objectid,
  79                                       u64 flags, u64 owner, u64 offset,
  80                                       struct btrfs_key *ins, int ref_mod);
  81 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  82                                      struct btrfs_fs_info *fs_info,
  83                                      u64 parent, u64 root_objectid,
  84                                      u64 flags, struct btrfs_disk_key *key,
  85                                      int level, struct btrfs_key *ins);
  86 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
  87                           struct btrfs_fs_info *fs_info, u64 flags,
  88                           int force);
  89 static int find_next_key(struct btrfs_path *path, int level,
  90                          struct btrfs_key *key);
  91 static void dump_space_info(struct btrfs_fs_info *fs_info,
  92                             struct btrfs_space_info *info, u64 bytes,
  93                             int dump_block_groups);
  94 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
  95                                     u64 ram_bytes, u64 num_bytes, int delalloc);
  96 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
  97                                      u64 num_bytes, int delalloc);
  98 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
  99                                u64 num_bytes);
 100 static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
 101                                     struct btrfs_space_info *space_info,
 102                                     u64 orig_bytes,
 103                                     enum btrfs_reserve_flush_enum flush,
 104                                     bool system_chunk);
 105 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
 106                                      struct btrfs_space_info *space_info,
 107                                      u64 num_bytes);
 108 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
 109                                      struct btrfs_space_info *space_info,
 110                                      u64 num_bytes);
 111
 112 static noinline int
 113 block_group_cache_done(struct btrfs_block_group_cache *cache)
 114 {
 115         smp_mb();
 116         return cache->cached == BTRFS_CACHE_FINISHED ||
 117                 cache->cached == BTRFS_CACHE_ERROR;
 118 }
 119
 120 static int block_group_bits(struct btrfs_block_group_cache *cache, u64 bits)
 121 {
 122         return (cache->flags & bits) == bits;
 123 }
 124
 125 void btrfs_get_block_group(struct btrfs_block_group_cache *cache)
 126 {
 127         atomic_inc(&cache->count);
 128 }
 129
 130 void btrfs_put_block_group(struct btrfs_block_group_cache *cache)
 131 {
 132         if (atomic_dec_and_test(&cache->count)) {
 133                 WARN_ON(cache->pinned > 0);
 134                 WARN_ON(cache->reserved > 0);
 135
 136                 /*
 137                  * If not empty, someone is still holding mutex of
 138                  * full_stripe_lock, which can only be released by caller.
 139                  * And it will definitely cause use-after-free when caller
 140                  * tries to release full stripe lock.
 141                  *
 142                  * No better way to resolve, but only to warn.
 143                  */
 144                 WARN_ON(!RB_EMPTY_ROOT(&cache->full_stripe_locks_root.root));
 145                 kfree(cache->free_space_ctl);
 146                 kfree(cache);
 147         }
 148 }
 149
 150 /*
 151  * this adds the block group to the fs_info rb tree for the block group
 152  * cache
 153  */
 154 static int btrfs_add_block_group_cache(struct btrfs_fs_info *info,
 155                                 struct btrfs_block_group_cache *block_group)
 156 {
 157         struct rb_node **p;
 158         struct rb_node *parent = NULL;
 159         struct btrfs_block_group_cache *cache;
 160
 161         spin_lock(&info->block_group_cache_lock);
 162         p = &info->block_group_cache_tree.rb_node;
 163
 164         while (*p) {
 165                 parent = *p;
 166                 cache = rb_entry(parent, struct btrfs_block_group_cache,
 167                                  cache_node);
 168                 if (block_group->key.objectid < cache->key.objectid) {
 169                         p = &(*p)->rb_left;
 170                 } else if (block_group->key.objectid > cache->key.objectid) {
 171                         p = &(*p)->rb_right;
 172                 } else {
 173                         spin_unlock(&info->block_group_cache_lock);
 174                         return -EEXIST;
 175                 }
 176         }
 177
 178         rb_link_node(&block_group->cache_node, parent, p);
 179         rb_insert_color(&block_group->cache_node,
 180                         &info->block_group_cache_tree);
 181
 182         if (info->first_logical_byte > block_group->key.objectid)
 183                 info->first_logical_byte = block_group->key.objectid;
 184
 185         spin_unlock(&info->block_group_cache_lock);
 186
 187         return 0;
 188 }
 189
 190 /*
 191  * This will return the block group at or after bytenr if contains is 0, else
 192  * it will return the block group that contains the bytenr
 193  */
 194 static struct btrfs_block_group_cache *
 195 block_group_cache_tree_search(struct btrfs_fs_info *info, u64 bytenr,
 196                               int contains)
 197 {
 198         struct btrfs_block_group_cache *cache, *ret = NULL;
 199         struct rb_node *n;
 200         u64 end, start;
 201
 202         spin_lock(&info->block_group_cache_lock);
 203         n = info->block_group_cache_tree.rb_node;
 204
 205         while (n) {
 206                 cache = rb_entry(n, struct btrfs_block_group_cache,
 207                                  cache_node);
 208                 end = cache->key.objectid + cache->key.offset - 1;
 209                 start = cache->key.objectid;
 210
 211                 if (bytenr < start) {
 212                         if (!contains && (!ret || start < ret->key.objectid))
 213                                 ret = cache;
 214                         n = n->rb_left;
 215                 } else if (bytenr > start) {
 216                         if (contains && bytenr <= end) {
 217                                 ret = cache;
 218                                 break;
 219                         }
 220                         n = n->rb_right;
 221                 } else {
 222                         ret = cache;
 223                         break;
 224                 }
 225         }
 226         if (ret) {
 227                 btrfs_get_block_group(ret);
 228                 if (bytenr == 0 && info->first_logical_byte > ret->key.objectid)
 229                         info->first_logical_byte = ret->key.objectid;
 230         }
 231         spin_unlock(&info->block_group_cache_lock);
 232
 233         return ret;
 234 }
 235
 236 static int add_excluded_extent(struct btrfs_fs_info *fs_info,
 237                                u64 start, u64 num_bytes)
 238 {
 239         u64 end = start + num_bytes - 1;
 240         set_extent_bits(&fs_info->freed_extents[0],
 241                         start, end, EXTENT_UPTODATE);
 242         set_extent_bits(&fs_info->freed_extents[1],
 243                         start, end, EXTENT_UPTODATE);
 244         return 0;
 245 }
 246
 247 static void free_excluded_extents(struct btrfs_fs_info *fs_info,
 248                                   struct btrfs_block_group_cache *cache)
 249 {
 250         u64 start, end;
 251
 252         start = cache->key.objectid;
 253         end = start + cache->key.offset - 1;
 254
 255         clear_extent_bits(&fs_info->freed_extents[0],
 256                           start, end, EXTENT_UPTODATE);
 257         clear_extent_bits(&fs_info->freed_extents[1],
 258                           start, end, EXTENT_UPTODATE);
 259 }
 260
 261 static int exclude_super_stripes(struct btrfs_fs_info *fs_info,
 262                                  struct btrfs_block_group_cache *cache)
 263 {
 264         u64 bytenr;
 265         u64 *logical;
 266         int stripe_len;
 267         int i, nr, ret;
 268
 269         if (cache->key.objectid < BTRFS_SUPER_INFO_OFFSET) {
 270                 stripe_len = BTRFS_SUPER_INFO_OFFSET - cache->key.objectid;
 271                 cache->bytes_super += stripe_len;
 272                 ret = add_excluded_extent(fs_info, cache->key.objectid,
 273                                           stripe_len);
 274                 if (ret)
 275                         return ret;
 276         }
 277
 278         for (i = 0; i < BTRFS_SUPER_MIRROR_MAX; i++) {
 279                 bytenr = btrfs_sb_offset(i);
 280                 ret = btrfs_rmap_block(fs_info, cache->key.objectid,
 281                                        bytenr, 0, &logical, &nr, &stripe_len);
 282                 if (ret)
 283                         return ret;
 284
 285                 while (nr--) {
 286                         u64 start, len;
 287
 288                         if (logical[nr] > cache->key.objectid +
 289                             cache->key.offset)
 290                                 continue;
 291
 292                         if (logical[nr] + stripe_len <= cache->key.objectid)
 293                                 continue;
 294
 295                         start = logical[nr];
 296                         if (start < cache->key.objectid) {
 297                                 start = cache->key.objectid;
 298                                 len = (logical[nr] + stripe_len) - start;
 299                         } else {
 300                                 len = min_t(u64, stripe_len,
 301                                             cache->key.objectid +
 302                                             cache->key.offset - start);
 303                         }
 304
 305                         cache->bytes_super += len;
 306                         ret = add_excluded_extent(fs_info, start, len);
 307                         if (ret) {
 308                                 kfree(logical);
 309                                 return ret;
 310                         }
 311                 }
 312
 313                 kfree(logical);
 314         }
 315         return 0;
 316 }
 317
 318 static struct btrfs_caching_control *
 319 get_caching_control(struct btrfs_block_group_cache *cache)
 320 {
 321         struct btrfs_caching_control *ctl;
 322
 323         spin_lock(&cache->lock);
 324         if (!cache->caching_ctl) {
 325                 spin_unlock(&cache->lock);
 326                 return NULL;
 327         }
 328
 329         ctl = cache->caching_ctl;
 330         refcount_inc(&ctl->count);
 331         spin_unlock(&cache->lock);
 332         return ctl;
 333 }
 334
 335 static void put_caching_control(struct btrfs_caching_control *ctl)
 336 {
 337         if (refcount_dec_and_test(&ctl->count))
 338                 kfree(ctl);
 339 }
 340
 341 #ifdef CONFIG_BTRFS_DEBUG
 342 static void fragment_free_space(struct btrfs_block_group_cache *block_group)
 343 {
 344         struct btrfs_fs_info *fs_info = block_group->fs_info;
 345         u64 start = block_group->key.objectid;
 346         u64 len = block_group->key.offset;
 347         u64 chunk = block_group->flags & BTRFS_BLOCK_GROUP_METADATA ?
 348                 fs_info->nodesize : fs_info->sectorsize;
 349         u64 step = chunk << 1;
 350
 351         while (len > chunk) {
 352                 btrfs_remove_free_space(block_group, start, chunk);
 353                 start += step;
 354                 if (len < step)
 355                         len = 0;
 356                 else
 357                         len -= step;
 358         }
 359 }
 360 #endif
 361
 362 /*
 363  * this is only called by cache_block_group, since we could have freed extents
 364  * we need to check the pinned_extents for any extents that can't be used yet
 365  * since their free space will be released as soon as the transaction commits.
 366  */
 367 u64 add_new_free_space(struct btrfs_block_group_cache *block_group,
 368                        struct btrfs_fs_info *info, u64 start, u64 end)
 369 {
 370         u64 extent_start, extent_end, size, total_added = 0;
 371         int ret;
 372
 373         while (start < end) {
 374                 ret = find_first_extent_bit(info->pinned_extents, start,
 375                                             &extent_start, &extent_end,
 376                                             EXTENT_DIRTY | EXTENT_UPTODATE,
 377                                             NULL);
 378                 if (ret)
 379                         break;
 380
 381                 if (extent_start <= start) {
 382                         start = extent_end + 1;
 383                 } else if (extent_start > start && extent_start < end) {
 384                         size = extent_start - start;
 385                         total_added += size;
 386                         ret = btrfs_add_free_space(block_group, start,
 387                                                    size);
 388                         BUG_ON(ret); /* -ENOMEM or logic error */
 389                         start = extent_end + 1;
 390                 } else {
 391                         break;
 392                 }
 393         }
 394
 395         if (start < end) {
 396                 size = end - start;
 397                 total_added += size;
 398                 ret = btrfs_add_free_space(block_group, start, size);
 399                 BUG_ON(ret); /* -ENOMEM or logic error */
 400         }
 401
 402         return total_added;
 403 }
 404
 405 static int load_extent_tree_free(struct btrfs_caching_control *caching_ctl)
 406 {
 407         struct btrfs_block_group_cache *block_group = caching_ctl->block_group;
 408         struct btrfs_fs_info *fs_info = block_group->fs_info;
 409         struct btrfs_root *extent_root = fs_info->extent_root;
 410         struct btrfs_path *path;
 411         struct extent_buffer *leaf;
 412         struct btrfs_key key;
 413         u64 total_found = 0;
 414         u64 last = 0;
 415         u32 nritems;
 416         int ret;
 417         bool wakeup = true;
 418
 419         path = btrfs_alloc_path();
 420         if (!path)
 421                 return -ENOMEM;
 422
 423         last = max_t(u64, block_group->key.objectid, BTRFS_SUPER_INFO_OFFSET);
 424
 425 #ifdef CONFIG_BTRFS_DEBUG
 426         /*
 427          * If we're fragmenting we don't want to make anybody think we can
 428          * allocate from this block group until we've had a chance to fragment
 429          * the free space.
 430          */
 431         if (btrfs_should_fragment_free_space(block_group))
 432                 wakeup = false;
 433 #endif
 434         /*
 435          * We don't want to deadlock with somebody trying to allocate a new
 436          * extent for the extent root while also trying to search the extent
 437          * root to add free space.  So we skip locking and search the commit
 438          * root, since its read-only
 439          */
 440         path->skip_locking = 1;
 441         path->search_commit_root = 1;
 442         path->reada = READA_FORWARD;
 443
 444         key.objectid = last;
 445         key.offset = 0;
 446         key.type = BTRFS_EXTENT_ITEM_KEY;
 447
 448 next:
 449         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 450         if (ret < 0)
 451                 goto out;
 452
 453         leaf = path->nodes[0];
 454         nritems = btrfs_header_nritems(leaf);
 455
 456         while (1) {
 457                 if (btrfs_fs_closing(fs_info) > 1) {
 458                         last = (u64)-1;
 459                         break;
 460                 }
 461
 462                 if (path->slots[0] < nritems) {
 463                         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 464                 } else {
 465                         ret = find_next_key(path, 0, &key);
 466                         if (ret)
 467                                 break;
 468
 469                         if (need_resched() ||
 470                             rwsem_is_contended(&fs_info->commit_root_sem)) {
 471                                 if (wakeup)
 472                                         caching_ctl->progress = last;
 473                                 btrfs_release_path(path);
 474                                 up_read(&fs_info->commit_root_sem);
 475                                 mutex_unlock(&caching_ctl->mutex);
 476                                 cond_resched();
 477                                 mutex_lock(&caching_ctl->mutex);
 478                                 down_read(&fs_info->commit_root_sem);
 479                                 goto next;
 480                         }
 481
 482                         ret = btrfs_next_leaf(extent_root, path);
 483                         if (ret < 0)
 484                                 goto out;
 485                         if (ret)
 486                                 break;
 487                         leaf = path->nodes[0];
 488                         nritems = btrfs_header_nritems(leaf);
 489                         continue;
 490                 }
 491
 492                 if (key.objectid < last) {
 493                         key.objectid = last;
 494                         key.offset = 0;
 495                         key.type = BTRFS_EXTENT_ITEM_KEY;
 496
 497                         if (wakeup)
 498                                 caching_ctl->progress = last;
 499                         btrfs_release_path(path);
 500                         goto next;
 501                 }
 502
 503                 if (key.objectid < block_group->key.objectid) {
 504                         path->slots[0]++;
 505                         continue;
 506                 }
 507
 508                 if (key.objectid >= block_group->key.objectid +
 509                     block_group->key.offset)
 510                         break;
 511
 512                 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
 513                     key.type == BTRFS_METADATA_ITEM_KEY) {
 514                         total_found += add_new_free_space(block_group,
 515                                                           fs_info, last,
 516                                                           key.objectid);
 517                         if (key.type == BTRFS_METADATA_ITEM_KEY)
 518                                 last = key.objectid +
 519                                         fs_info->nodesize;
 520                         else
 521                                 last = key.objectid + key.offset;
 522
 523                         if (total_found > CACHING_CTL_WAKE_UP) {
 524                                 total_found = 0;
 525                                 if (wakeup)
 526                                         wake_up(&caching_ctl->wait);
 527                         }
 528                 }
 529                 path->slots[0]++;
 530         }
 531         ret = 0;
 532
 533         total_found += add_new_free_space(block_group, fs_info, last,
 534                                           block_group->key.objectid +
 535                                           block_group->key.offset);
 536         caching_ctl->progress = (u64)-1;
 537
 538 out:
 539         btrfs_free_path(path);
 540         return ret;
 541 }
 542
 543 static noinline void caching_thread(struct btrfs_work *work)
 544 {
 545         struct btrfs_block_group_cache *block_group;
 546         struct btrfs_fs_info *fs_info;
 547         struct btrfs_caching_control *caching_ctl;
 548         struct btrfs_root *extent_root;
 549         int ret;
 550
 551         caching_ctl = container_of(work, struct btrfs_caching_control, work);
 552         block_group = caching_ctl->block_group;
 553         fs_info = block_group->fs_info;
 554         extent_root = fs_info->extent_root;
 555
 556         mutex_lock(&caching_ctl->mutex);
 557         down_read(&fs_info->commit_root_sem);
 558
 559         if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
 560                 ret = load_free_space_tree(caching_ctl);
 561         else
 562                 ret = load_extent_tree_free(caching_ctl);
 563
 564         spin_lock(&block_group->lock);
 565         block_group->caching_ctl = NULL;
 566         block_group->cached = ret ? BTRFS_CACHE_ERROR : BTRFS_CACHE_FINISHED;
 567         spin_unlock(&block_group->lock);
 568
 569 #ifdef CONFIG_BTRFS_DEBUG
 570         if (btrfs_should_fragment_free_space(block_group)) {
 571                 u64 bytes_used;
 572
 573                 spin_lock(&block_group->space_info->lock);
 574                 spin_lock(&block_group->lock);
 575                 bytes_used = block_group->key.offset -
 576                         btrfs_block_group_used(&block_group->item);
 577                 block_group->space_info->bytes_used += bytes_used >> 1;
 578                 spin_unlock(&block_group->lock);
 579                 spin_unlock(&block_group->space_info->lock);
 580                 fragment_free_space(block_group);
 581         }
 582 #endif
 583
 584         caching_ctl->progress = (u64)-1;
 585
 586         up_read(&fs_info->commit_root_sem);
 587         free_excluded_extents(fs_info, block_group);
 588         mutex_unlock(&caching_ctl->mutex);
 589
 590         wake_up(&caching_ctl->wait);
 591
 592         put_caching_control(caching_ctl);
 593         btrfs_put_block_group(block_group);
 594 }
 595
 596 static int cache_block_group(struct btrfs_block_group_cache *cache,
 597                              int load_cache_only)
 598 {
 599         DEFINE_WAIT(wait);
 600         struct btrfs_fs_info *fs_info = cache->fs_info;
 601         struct btrfs_caching_control *caching_ctl;
 602         int ret = 0;
 603
 604         caching_ctl = kzalloc(sizeof(*caching_ctl), GFP_NOFS);
 605         if (!caching_ctl)
 606                 return -ENOMEM;
 607
 608         INIT_LIST_HEAD(&caching_ctl->list);
 609         mutex_init(&caching_ctl->mutex);
 610         init_waitqueue_head(&caching_ctl->wait);
 611         caching_ctl->block_group = cache;
 612         caching_ctl->progress = cache->key.objectid;
 613         refcount_set(&caching_ctl->count, 1);
 614         btrfs_init_work(&caching_ctl->work, btrfs_cache_helper,
 615                         caching_thread, NULL, NULL);
 616
 617         spin_lock(&cache->lock);
 618         /*
 619          * This should be a rare occasion, but this could happen I think in the
 620          * case where one thread starts to load the space cache info, and then
 621          * some other thread starts a transaction commit which tries to do an
 622          * allocation while the other thread is still loading the space cache
 623          * info.  The previous loop should have kept us from choosing this block
 624          * group, but if we've moved to the state where we will wait on caching
 625          * block groups we need to first check if we're doing a fast load here,
 626          * so we can wait for it to finish, otherwise we could end up allocating
 627          * from a block group who's cache gets evicted for one reason or
 628          * another.
 629          */
 630         while (cache->cached == BTRFS_CACHE_FAST) {
 631                 struct btrfs_caching_control *ctl;
 632
 633                 ctl = cache->caching_ctl;
 634                 refcount_inc(&ctl->count);
 635                 prepare_to_wait(&ctl->wait, &wait, TASK_UNINTERRUPTIBLE);
 636                 spin_unlock(&cache->lock);
 637
 638                 schedule();
 639
 640                 finish_wait(&ctl->wait, &wait);
 641                 put_caching_control(ctl);
 642                 spin_lock(&cache->lock);
 643         }
 644
 645         if (cache->cached != BTRFS_CACHE_NO) {
 646                 spin_unlock(&cache->lock);
 647                 kfree(caching_ctl);
 648                 return 0;
 649         }
 650         WARN_ON(cache->caching_ctl);
 651         cache->caching_ctl = caching_ctl;
 652         cache->cached = BTRFS_CACHE_FAST;
 653         spin_unlock(&cache->lock);
 654
 655         if (fs_info->mount_opt & BTRFS_MOUNT_SPACE_CACHE) {
 656                 mutex_lock(&caching_ctl->mutex);
 657                 ret = load_free_space_cache(fs_info, cache);
 658
 659                 spin_lock(&cache->lock);
 660                 if (ret == 1) {
 661                         cache->caching_ctl = NULL;
 662                         cache->cached = BTRFS_CACHE_FINISHED;
 663                         cache->last_byte_to_unpin = (u64)-1;
 664                         caching_ctl->progress = (u64)-1;
 665                 } else {
 666                         if (load_cache_only) {
 667                                 cache->caching_ctl = NULL;
 668                                 cache->cached = BTRFS_CACHE_NO;
 669                         } else {
 670                                 cache->cached = BTRFS_CACHE_STARTED;
 671                                 cache->has_caching_ctl = 1;
 672                         }
 673                 }
 674                 spin_unlock(&cache->lock);
 675 #ifdef CONFIG_BTRFS_DEBUG
 676                 if (ret == 1 &&
 677                     btrfs_should_fragment_free_space(cache)) {
 678                         u64 bytes_used;
 679
 680                         spin_lock(&cache->space_info->lock);
 681                         spin_lock(&cache->lock);
 682                         bytes_used = cache->key.offset -
 683                                 btrfs_block_group_used(&cache->item);
 684                         cache->space_info->bytes_used += bytes_used >> 1;
 685                         spin_unlock(&cache->lock);
 686                         spin_unlock(&cache->space_info->lock);
 687                         fragment_free_space(cache);
 688                 }
 689 #endif
 690                 mutex_unlock(&caching_ctl->mutex);
 691
 692                 wake_up(&caching_ctl->wait);
 693                 if (ret == 1) {
 694                         put_caching_control(caching_ctl);
 695                         free_excluded_extents(fs_info, cache);
 696                         return 0;
 697                 }
 698         } else {
 699                 /*
 700                  * We're either using the free space tree or no caching at all.
 701                  * Set cached to the appropriate value and wakeup any waiters.
 702                  */
 703                 spin_lock(&cache->lock);
 704                 if (load_cache_only) {
 705                         cache->caching_ctl = NULL;
 706                         cache->cached = BTRFS_CACHE_NO;
 707                 } else {
 708                         cache->cached = BTRFS_CACHE_STARTED;
 709                         cache->has_caching_ctl = 1;
 710                 }
 711                 spin_unlock(&cache->lock);
 712                 wake_up(&caching_ctl->wait);
 713         }
 714
 715         if (load_cache_only) {
 716                 put_caching_control(caching_ctl);
 717                 return 0;
 718         }
 719
 720         down_write(&fs_info->commit_root_sem);
 721         refcount_inc(&caching_ctl->count);
 722         list_add_tail(&caching_ctl->list, &fs_info->caching_block_groups);
 723         up_write(&fs_info->commit_root_sem);
 724
 725         btrfs_get_block_group(cache);
 726
 727         btrfs_queue_work(fs_info->caching_workers, &caching_ctl->work);
 728
 729         return ret;
 730 }
 731
 732 /*
 733  * return the block group that starts at or after bytenr
 734  */
 735 static struct btrfs_block_group_cache *
 736 btrfs_lookup_first_block_group(struct btrfs_fs_info *info, u64 bytenr)
 737 {
 738         return block_group_cache_tree_search(info, bytenr, 0);
 739 }
 740
 741 /*
 742  * return the block group that contains the given bytenr
 743  */
 744 struct btrfs_block_group_cache *btrfs_lookup_block_group(
 745                                                  struct btrfs_fs_info *info,
 746                                                  u64 bytenr)
 747 {
 748         return block_group_cache_tree_search(info, bytenr, 1);
 749 }
 750
 751 static struct btrfs_space_info *__find_space_info(struct btrfs_fs_info *info,
 752                                                   u64 flags)
 753 {
 754         struct list_head *head = &info->space_info;
 755         struct btrfs_space_info *found;
 756
 757         flags &= BTRFS_BLOCK_GROUP_TYPE_MASK;
 758
 759         rcu_read_lock();
 760         list_for_each_entry_rcu(found, head, list) {
 761                 if (found->flags & flags) {
 762                         rcu_read_unlock();
 763                         return found;
 764                 }
 765         }
 766         rcu_read_unlock();
 767         return NULL;
 768 }
 769
 770 static void add_pinned_bytes(struct btrfs_fs_info *fs_info, s64 num_bytes,
 771                              u64 owner, u64 root_objectid)
 772 {
 773         struct btrfs_space_info *space_info;
 774         u64 flags;
 775
 776         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 777                 if (root_objectid == BTRFS_CHUNK_TREE_OBJECTID)
 778                         flags = BTRFS_BLOCK_GROUP_SYSTEM;
 779                 else
 780                         flags = BTRFS_BLOCK_GROUP_METADATA;
 781         } else {
 782                 flags = BTRFS_BLOCK_GROUP_DATA;
 783         }
 784
 785         space_info = __find_space_info(fs_info, flags);
 786         ASSERT(space_info);
 787         percpu_counter_add(&space_info->total_bytes_pinned, num_bytes);
 788 }
 789
 790 /*
 791  * after adding space to the filesystem, we need to clear the full flags
 792  * on all the space infos.
 793  */
 794 void btrfs_clear_space_info_full(struct btrfs_fs_info *info)
 795 {
 796         struct list_head *head = &info->space_info;
 797         struct btrfs_space_info *found;
 798
 799         rcu_read_lock();
 800         list_for_each_entry_rcu(found, head, list)
 801                 found->full = 0;
 802         rcu_read_unlock();
 803 }
 804
 805 /* simple helper to search for an existing data extent at a given offset */
 806 int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
 807 {
 808         int ret;
 809         struct btrfs_key key;
 810         struct btrfs_path *path;
 811
 812         path = btrfs_alloc_path();
 813         if (!path)
 814                 return -ENOMEM;
 815
 816         key.objectid = start;
 817         key.offset = len;
 818         key.type = BTRFS_EXTENT_ITEM_KEY;
 819         ret = btrfs_search_slot(NULL, fs_info->extent_root, &key, path, 0, 0);
 820         btrfs_free_path(path);
 821         return ret;
 822 }
 823
 824 /*
 825  * helper function to lookup reference count and flags of a tree block.
 826  *
 827  * the head node for delayed ref is used to store the sum of all the
 828  * reference count modifications queued up in the rbtree. the head
 829  * node may also store the extent flags to set. This way you can check
 830  * to see what the reference count and extent flags would be if all of
 831  * the delayed refs are not processed.
 832  */
 833 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 834                              struct btrfs_fs_info *fs_info, u64 bytenr,
 835                              u64 offset, int metadata, u64 *refs, u64 *flags)
 836 {
 837         struct btrfs_delayed_ref_head *head;
 838         struct btrfs_delayed_ref_root *delayed_refs;
 839         struct btrfs_path *path;
 840         struct btrfs_extent_item *ei;
 841         struct extent_buffer *leaf;
 842         struct btrfs_key key;
 843         u32 item_size;
 844         u64 num_refs;
 845         u64 extent_flags;
 846         int ret;
 847
 848         /*
 849          * If we don't have skinny metadata, don't bother doing anything
 850          * different
 851          */
 852         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
 853                 offset = fs_info->nodesize;
 854                 metadata = 0;
 855         }
 856
 857         path = btrfs_alloc_path();
 858         if (!path)
 859                 return -ENOMEM;
 860
 861         if (!trans) {
 862                 path->skip_locking = 1;
 863                 path->search_commit_root = 1;
 864         }
 865
 866 search_again:
 867         key.objectid = bytenr;
 868         key.offset = offset;
 869         if (metadata)
 870                 key.type = BTRFS_METADATA_ITEM_KEY;
 871         else
 872                 key.type = BTRFS_EXTENT_ITEM_KEY;
 873
 874         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 0);
 875         if (ret < 0)
 876                 goto out_free;
 877
 878         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 879                 if (path->slots[0]) {
 880                         path->slots[0]--;
 881                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 882                                               path->slots[0]);
 883                         if (key.objectid == bytenr &&
 884                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 885                             key.offset == fs_info->nodesize)
 886                                 ret = 0;
 887                 }
 888         }
 889
 890         if (ret == 0) {
 891                 leaf = path->nodes[0];
 892                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
 893                 if (item_size >= sizeof(*ei)) {
 894                         ei = btrfs_item_ptr(leaf, path->slots[0],
 895                                             struct btrfs_extent_item);
 896                         num_refs = btrfs_extent_refs(leaf, ei);
 897                         extent_flags = btrfs_extent_flags(leaf, ei);
 898                 } else {
 899 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
 900                         struct btrfs_extent_item_v0 *ei0;
 901                         BUG_ON(item_size != sizeof(*ei0));
 902                         ei0 = btrfs_item_ptr(leaf, path->slots[0],
 903                                              struct btrfs_extent_item_v0);
 904                         num_refs = btrfs_extent_refs_v0(leaf, ei0);
 905                         /* FIXME: this isn't correct for data */
 906                         extent_flags = BTRFS_BLOCK_FLAG_FULL_BACKREF;
 907 #else
 908                         BUG();
 909 #endif
 910                 }
 911                 BUG_ON(num_refs == 0);
 912         } else {
 913                 num_refs = 0;
 914                 extent_flags = 0;
 915                 ret = 0;
 916         }
 917
 918         if (!trans)
 919                 goto out;
 920
 921         delayed_refs = &trans->transaction->delayed_refs;
 922         spin_lock(&delayed_refs->lock);
 923         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 924         if (head) {
 925                 if (!mutex_trylock(&head->mutex)) {
 926                         refcount_inc(&head->node.refs);
 927                         spin_unlock(&delayed_refs->lock);
 928
 929                         btrfs_release_path(path);
 930
 931                         /*
 932                          * Mutex was contended, block until it's released and try
 933                          * again
 934                          */
 935                         mutex_lock(&head->mutex);
 936                         mutex_unlock(&head->mutex);
 937                         btrfs_put_delayed_ref(&head->node);
 938                         goto search_again;
 939                 }
 940                 spin_lock(&head->lock);
 941                 if (head->extent_op && head->extent_op->update_flags)
 942                         extent_flags |= head->extent_op->flags_to_set;
 943                 else
 944                         BUG_ON(num_refs == 0);
 945
 946                 num_refs += head->node.ref_mod;
 947                 spin_unlock(&head->lock);
 948                 mutex_unlock(&head->mutex);
 949         }
 950         spin_unlock(&delayed_refs->lock);
 951 out:
 952         WARN_ON(num_refs == 0);
 953         if (refs)
 954                 *refs = num_refs;
 955         if (flags)
 956                 *flags = extent_flags;
 957 out_free:
 958         btrfs_free_path(path);
 959         return ret;
 960 }
 961
 962 /*
 963  * Back reference rules.  Back refs have three main goals:
 964  *
 965  * 1) differentiate between all holders of references to an extent so that
 966  *    when a reference is dropped we can make sure it was a valid reference
 967  *    before freeing the extent.
 968  *
 969  * 2) Provide enough information to quickly find the holders of an extent
 970  *    if we notice a given block is corrupted or bad.
 971  *
 972  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 973  *    maintenance.  This is actually the same as #2, but with a slightly
 974  *    different use case.
 975  *
 976  * There are two kinds of back refs. The implicit back refs is optimized
 977  * for pointers in non-shared tree blocks. For a given pointer in a block,
 978  * back refs of this kind provide information about the block's owner tree
 979  * and the pointer's key. These information allow us to find the block by
 980  * b-tree searching. The full back refs is for pointers in tree blocks not
 981  * referenced by their owner trees. The location of tree block is recorded
 982  * in the back refs. Actually the full back refs is generic, and can be
 983  * used in all cases the implicit back refs is used. The major shortcoming
 984  * of the full back refs is its overhead. Every time a tree block gets
 985  * COWed, we have to update back refs entry for all pointers in it.
 986  *
 987  * For a newly allocated tree block, we use implicit back refs for
 988  * pointers in it. This means most tree related operations only involve
 989  * implicit back refs. For a tree block created in old transaction, the
 990  * only way to drop a reference to it is COW it. So we can detect the
 991  * event that tree block loses its owner tree's reference and do the
 992  * back refs conversion.
 993  *
 994  * When a tree block is COWed through a tree, there are four cases:
 995  *
 996  * The reference count of the block is one and the tree is the block's
 997  * owner tree. Nothing to do in this case.
 998  *
 999  * The reference count of the block is one and the tree is not the
1000  * block's owner tree. In this case, full back refs is used for pointers
1001  * in the block. Remove these full back refs, add implicit back refs for
1002  * every pointers in the new block.
1003  *
1004  * The reference count of the block is greater than one and the tree is
1005  * the block's owner tree. In this case, implicit back refs is used for
1006  * pointers in the block. Add full back refs for every pointers in the
1007  * block, increase lower level extents' reference counts. The original
1008  * implicit back refs are entailed to the new block.
1009  *
1010  * The reference count of the block is greater than one and the tree is
1011  * not the block's owner tree. Add implicit back refs for every pointer in
1012  * the new block, increase lower level extents' reference count.
1013  *
1014  * Back Reference Key composing:
1015  *
1016  * The key objectid corresponds to the first byte in the extent,
1017  * The key type is used to differentiate between types of back refs.
1018  * There are different meanings of the key offset for different types
1019  * of back refs.
1020  *
1021  * File extents can be referenced by:
1022  *
1023  * - multiple snapshots, subvolumes, or different generations in one subvol
1024  * - different files inside a single subvolume
1025  * - different offsets inside a file (bookend extents in file.c)
1026  *
1027  * The extent ref structure for the implicit back refs has fields for:
1028  *
1029  * - Objectid of the subvolume root
1030  * - objectid of the file holding the reference
1031  * - original offset in the file
1032  * - how many bookend extents
1033  *
1034  * The key offset for the implicit back refs is hash of the first
1035  * three fields.
1036  *
1037  * The extent ref structure for the full back refs has field for:
1038  *
1039  * - number of pointers in the tree leaf
1040  *
1041  * The key offset for the implicit back refs is the first byte of
1042  * the tree leaf
1043  *
1044  * When a file extent is allocated, The implicit back refs is used.
1045  * the fields are filled in:
1046  *
1047  *     (root_key.objectid, inode objectid, offset in file, 1)
1048  *
1049  * When a file extent is removed file truncation, we find the
1050  * corresponding implicit back refs and check the following fields:
1051  *
1052  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
1053  *
1054  * Btree extents can be referenced by:
1055  *
1056  * - Different subvolumes
1057  *
1058  * Both the implicit back refs and the full back refs for tree blocks
1059  * only consist of key. The key offset for the implicit back refs is
1060  * objectid of block's owner tree. The key offset for the full back refs
1061  * is the first byte of parent block.
1062  *
1063  * When implicit back refs is used, information about the lowest key and
1064  * level of the tree block are required. These information are stored in
1065  * tree block info structure.
1066  */
1067
1068 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1069 static int convert_extent_item_v0(struct btrfs_trans_handle *trans,
1070                                   struct btrfs_fs_info *fs_info,
1071                                   struct btrfs_path *path,
1072                                   u64 owner, u32 extra_size)
1073 {
1074         struct btrfs_root *root = fs_info->extent_root;
1075         struct btrfs_extent_item *item;
1076         struct btrfs_extent_item_v0 *ei0;
1077         struct btrfs_extent_ref_v0 *ref0;
1078         struct btrfs_tree_block_info *bi;
1079         struct extent_buffer *leaf;
1080         struct btrfs_key key;
1081         struct btrfs_key found_key;
1082         u32 new_size = sizeof(*item);
1083         u64 refs;
1084         int ret;
1085
1086         leaf = path->nodes[0];
1087         BUG_ON(btrfs_item_size_nr(leaf, path->slots[0]) != sizeof(*ei0));
1088
1089         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1090         ei0 = btrfs_item_ptr(leaf, path->slots[0],
1091                              struct btrfs_extent_item_v0);
1092         refs = btrfs_extent_refs_v0(leaf, ei0);
1093
1094         if (owner == (u64)-1) {
1095                 while (1) {
1096                         if (path->slots[0] >= btrfs_header_nritems(leaf)) {
1097                                 ret = btrfs_next_leaf(root, path);
1098                                 if (ret < 0)
1099                                         return ret;
1100                                 BUG_ON(ret > 0); /* Corruption */
1101                                 leaf = path->nodes[0];
1102                         }
1103                         btrfs_item_key_to_cpu(leaf, &found_key,
1104                                               path->slots[0]);
1105                         BUG_ON(key.objectid != found_key.objectid);
1106                         if (found_key.type != BTRFS_EXTENT_REF_V0_KEY) {
1107                                 path->slots[0]++;
1108                                 continue;
1109                         }
1110                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1111                                               struct btrfs_extent_ref_v0);
1112                         owner = btrfs_ref_objectid_v0(leaf, ref0);
1113                         break;
1114                 }
1115         }
1116         btrfs_release_path(path);
1117
1118         if (owner < BTRFS_FIRST_FREE_OBJECTID)
1119                 new_size += sizeof(*bi);
1120
1121         new_size -= sizeof(*ei0);
1122         ret = btrfs_search_slot(trans, root, &key, path,
1123                                 new_size + extra_size, 1);
1124         if (ret < 0)
1125                 return ret;
1126         BUG_ON(ret); /* Corruption */
1127
1128         btrfs_extend_item(fs_info, path, new_size);
1129
1130         leaf = path->nodes[0];
1131         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1132         btrfs_set_extent_refs(leaf, item, refs);
1133         /* FIXME: get real generation */
1134         btrfs_set_extent_generation(leaf, item, 0);
1135         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1136                 btrfs_set_extent_flags(leaf, item,
1137                                        BTRFS_EXTENT_FLAG_TREE_BLOCK |
1138                                        BTRFS_BLOCK_FLAG_FULL_BACKREF);
1139                 bi = (struct btrfs_tree_block_info *)(item + 1);
1140                 /* FIXME: get first key of the block */
1141                 memzero_extent_buffer(leaf, (unsigned long)bi, sizeof(*bi));
1142                 btrfs_set_tree_block_level(leaf, bi, (int)owner);
1143         } else {
1144                 btrfs_set_extent_flags(leaf, item, BTRFS_EXTENT_FLAG_DATA);
1145         }
1146         btrfs_mark_buffer_dirty(leaf);
1147         return 0;
1148 }
1149 #endif
1150
1151 /*
1152  * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
1153  * is_data == BTRFS_REF_TYPE_DATA, data type is requried,
1154  * is_data == BTRFS_REF_TYPE_ANY, either type is OK.
1155  */
1156 int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
1157                                      struct btrfs_extent_inline_ref *iref,
1158                                      enum btrfs_inline_ref_type is_data)
1159 {
1160         int type = btrfs_extent_inline_ref_type(eb, iref);
1161         u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
1162
1163         if (type == BTRFS_TREE_BLOCK_REF_KEY ||
1164             type == BTRFS_SHARED_BLOCK_REF_KEY ||
1165             type == BTRFS_SHARED_DATA_REF_KEY ||
1166             type == BTRFS_EXTENT_DATA_REF_KEY) {
1167                 if (is_data == BTRFS_REF_TYPE_BLOCK) {
1168                         if (type == BTRFS_TREE_BLOCK_REF_KEY)
1169                                 return type;
1170                         if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1171                                 ASSERT(eb->fs_info);
1172                                 /*
1173                                  * Every shared one has parent tree block,
1174                                  * which must be aligned to sector size.
1175                                  */
1176                                 if (offset &&
1177                                     IS_ALIGNED(offset, eb->fs_info->sectorsize))
1178                                         return type;
1179                         }
1180                 } else if (is_data == BTRFS_REF_TYPE_DATA) {
1181                         if (type == BTRFS_EXTENT_DATA_REF_KEY)
1182                                 return type;
1183                         if (type == BTRFS_SHARED_DATA_REF_KEY) {
1184                                 ASSERT(eb->fs_info);
1185                                 /*
1186                                  * Every shared one has parent tree block,
1187                                  * which must be aligned to sector size.
1188                                  */
1189                                 if (offset &&
1190                                     IS_ALIGNED(offset, eb->fs_info->sectorsize))
1191                                         return type;
1192                         }
1193                 } else {
1194                         ASSERT(is_data == BTRFS_REF_TYPE_ANY);
1195                         return type;
1196                 }
1197         }
1198
1199         btrfs_print_leaf((struct extent_buffer *)eb);
1200         btrfs_err(eb->fs_info,
1201                   "eb %llu iref 0x%lx invalid extent inline ref type %d",
1202                   eb->start, (unsigned long)iref, type);
1203         WARN_ON(1);
1204
1205         return BTRFS_REF_TYPE_INVALID;
1206 }
1207
1208 static u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
1209 {
1210         u32 high_crc = ~(u32)0;
1211         u32 low_crc = ~(u32)0;
1212         __le64 lenum;
1213
1214         lenum = cpu_to_le64(root_objectid);
1215         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
1216         lenum = cpu_to_le64(owner);
1217         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1218         lenum = cpu_to_le64(offset);
1219         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
1220
1221         return ((u64)high_crc << 31) ^ (u64)low_crc;
1222 }
1223
1224 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
1225                                      struct btrfs_extent_data_ref *ref)
1226 {
1227         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
1228                                     btrfs_extent_data_ref_objectid(leaf, ref),
1229                                     btrfs_extent_data_ref_offset(leaf, ref));
1230 }
1231
1232 static int match_extent_data_ref(struct extent_buffer *leaf,
1233                                  struct btrfs_extent_data_ref *ref,
1234                                  u64 root_objectid, u64 owner, u64 offset)
1235 {
1236         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
1237             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
1238             btrfs_extent_data_ref_offset(leaf, ref) != offset)
1239                 return 0;
1240         return 1;
1241 }
1242
1243 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
1244                                            struct btrfs_fs_info *fs_info,
1245                                            struct btrfs_path *path,
1246                                            u64 bytenr, u64 parent,
1247                                            u64 root_objectid,
1248                                            u64 owner, u64 offset)
1249 {
1250         struct btrfs_root *root = fs_info->extent_root;
1251         struct btrfs_key key;
1252         struct btrfs_extent_data_ref *ref;
1253         struct extent_buffer *leaf;
1254         u32 nritems;
1255         int ret;
1256         int recow;
1257         int err = -ENOENT;
1258
1259         key.objectid = bytenr;
1260         if (parent) {
1261                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1262                 key.offset = parent;
1263         } else {
1264                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1265                 key.offset = hash_extent_data_ref(root_objectid,
1266                                                   owner, offset);
1267         }
1268 again:
1269         recow = 0;
1270         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1271         if (ret < 0) {
1272                 err = ret;
1273                 goto fail;
1274         }
1275
1276         if (parent) {
1277                 if (!ret)
1278                         return 0;
1279 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1280                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1281                 btrfs_release_path(path);
1282                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1283                 if (ret < 0) {
1284                         err = ret;
1285                         goto fail;
1286                 }
1287                 if (!ret)
1288                         return 0;
1289 #endif
1290                 goto fail;
1291         }
1292
1293         leaf = path->nodes[0];
1294         nritems = btrfs_header_nritems(leaf);
1295         while (1) {
1296                 if (path->slots[0] >= nritems) {
1297                         ret = btrfs_next_leaf(root, path);
1298                         if (ret < 0)
1299                                 err = ret;
1300                         if (ret)
1301                                 goto fail;
1302
1303                         leaf = path->nodes[0];
1304                         nritems = btrfs_header_nritems(leaf);
1305                         recow = 1;
1306                 }
1307
1308                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1309                 if (key.objectid != bytenr ||
1310                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
1311                         goto fail;
1312
1313                 ref = btrfs_item_ptr(leaf, path->slots[0],
1314                                      struct btrfs_extent_data_ref);
1315
1316                 if (match_extent_data_ref(leaf, ref, root_objectid,
1317                                           owner, offset)) {
1318                         if (recow) {
1319                                 btrfs_release_path(path);
1320                                 goto again;
1321                         }
1322                         err = 0;
1323                         break;
1324                 }
1325                 path->slots[0]++;
1326         }
1327 fail:
1328         return err;
1329 }
1330
1331 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
1332                                            struct btrfs_fs_info *fs_info,
1333                                            struct btrfs_path *path,
1334                                            u64 bytenr, u64 parent,
1335                                            u64 root_objectid, u64 owner,
1336                                            u64 offset, int refs_to_add)
1337 {
1338         struct btrfs_root *root = fs_info->extent_root;
1339         struct btrfs_key key;
1340         struct extent_buffer *leaf;
1341         u32 size;
1342         u32 num_refs;
1343         int ret;
1344
1345         key.objectid = bytenr;
1346         if (parent) {
1347                 key.type = BTRFS_SHARED_DATA_REF_KEY;
1348                 key.offset = parent;
1349                 size = sizeof(struct btrfs_shared_data_ref);
1350         } else {
1351                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
1352                 key.offset = hash_extent_data_ref(root_objectid,
1353                                                   owner, offset);
1354                 size = sizeof(struct btrfs_extent_data_ref);
1355         }
1356
1357         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
1358         if (ret && ret != -EEXIST)
1359                 goto fail;
1360
1361         leaf = path->nodes[0];
1362         if (parent) {
1363                 struct btrfs_shared_data_ref *ref;
1364                 ref = btrfs_item_ptr(leaf, path->slots[0],
1365                                      struct btrfs_shared_data_ref);
1366                 if (ret == 0) {
1367                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
1368                 } else {
1369                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
1370                         num_refs += refs_to_add;
1371                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
1372                 }
1373         } else {
1374                 struct btrfs_extent_data_ref *ref;
1375                 while (ret == -EEXIST) {
1376                         ref = btrfs_item_ptr(leaf, path->slots[0],
1377                                              struct btrfs_extent_data_ref);
1378                         if (match_extent_data_ref(leaf, ref, root_objectid,
1379                                                   owner, offset))
1380                                 break;
1381                         btrfs_release_path(path);
1382                         key.offset++;
1383                         ret = btrfs_insert_empty_item(trans, root, path, &key,
1384                                                       size);
1385                         if (ret && ret != -EEXIST)
1386                                 goto fail;
1387
1388                         leaf = path->nodes[0];
1389                 }
1390                 ref = btrfs_item_ptr(leaf, path->slots[0],
1391                                      struct btrfs_extent_data_ref);
1392                 if (ret == 0) {
1393                         btrfs_set_extent_data_ref_root(leaf, ref,
1394                                                        root_objectid);
1395                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
1396                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
1397                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
1398                 } else {
1399                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
1400                         num_refs += refs_to_add;
1401                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
1402                 }
1403         }
1404         btrfs_mark_buffer_dirty(leaf);
1405         ret = 0;
1406 fail:
1407         btrfs_release_path(path);
1408         return ret;
1409 }
1410
1411 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
1412                                            struct btrfs_fs_info *fs_info,
1413                                            struct btrfs_path *path,
1414                                            int refs_to_drop, int *last_ref)
1415 {
1416         struct btrfs_key key;
1417         struct btrfs_extent_data_ref *ref1 = NULL;
1418         struct btrfs_shared_data_ref *ref2 = NULL;
1419         struct extent_buffer *leaf;
1420         u32 num_refs = 0;
1421         int ret = 0;
1422
1423         leaf = path->nodes[0];
1424         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1425
1426         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1427                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1428                                       struct btrfs_extent_data_ref);
1429                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1430         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1431                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1432                                       struct btrfs_shared_data_ref);
1433                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1434 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1435         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1436                 struct btrfs_extent_ref_v0 *ref0;
1437                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1438                                       struct btrfs_extent_ref_v0);
1439                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1440 #endif
1441         } else {
1442                 BUG();
1443         }
1444
1445         BUG_ON(num_refs < refs_to_drop);
1446         num_refs -= refs_to_drop;
1447
1448         if (num_refs == 0) {
1449                 ret = btrfs_del_item(trans, fs_info->extent_root, path);
1450                 *last_ref = 1;
1451         } else {
1452                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
1453                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
1454                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
1455                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
1456 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1457                 else {
1458                         struct btrfs_extent_ref_v0 *ref0;
1459                         ref0 = btrfs_item_ptr(leaf, path->slots[0],
1460                                         struct btrfs_extent_ref_v0);
1461                         btrfs_set_ref_count_v0(leaf, ref0, num_refs);
1462                 }
1463 #endif
1464                 btrfs_mark_buffer_dirty(leaf);
1465         }
1466         return ret;
1467 }
1468
1469 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
1470                                           struct btrfs_extent_inline_ref *iref)
1471 {
1472         struct btrfs_key key;
1473         struct extent_buffer *leaf;
1474         struct btrfs_extent_data_ref *ref1;
1475         struct btrfs_shared_data_ref *ref2;
1476         u32 num_refs = 0;
1477         int type;
1478
1479         leaf = path->nodes[0];
1480         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1481         if (iref) {
1482                 /*
1483                  * If type is invalid, we should have bailed out earlier than
1484                  * this call.
1485                  */
1486                 type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
1487                 ASSERT(type != BTRFS_REF_TYPE_INVALID);
1488                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1489                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
1490                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1491                 } else {
1492                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
1493                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1494                 }
1495         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
1496                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
1497                                       struct btrfs_extent_data_ref);
1498                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
1499         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
1500                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
1501                                       struct btrfs_shared_data_ref);
1502                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
1503 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1504         } else if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
1505                 struct btrfs_extent_ref_v0 *ref0;
1506                 ref0 = btrfs_item_ptr(leaf, path->slots[0],
1507                                       struct btrfs_extent_ref_v0);
1508                 num_refs = btrfs_ref_count_v0(leaf, ref0);
1509 #endif
1510         } else {
1511                 WARN_ON(1);
1512         }
1513         return num_refs;
1514 }
1515
1516 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
1517                                           struct btrfs_fs_info *fs_info,
1518                                           struct btrfs_path *path,
1519                                           u64 bytenr, u64 parent,
1520                                           u64 root_objectid)
1521 {
1522         struct btrfs_root *root = fs_info->extent_root;
1523         struct btrfs_key key;
1524         int ret;
1525
1526         key.objectid = bytenr;
1527         if (parent) {
1528                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1529                 key.offset = parent;
1530         } else {
1531                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1532                 key.offset = root_objectid;
1533         }
1534
1535         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1536         if (ret > 0)
1537                 ret = -ENOENT;
1538 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1539         if (ret == -ENOENT && parent) {
1540                 btrfs_release_path(path);
1541                 key.type = BTRFS_EXTENT_REF_V0_KEY;
1542                 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1543                 if (ret > 0)
1544                         ret = -ENOENT;
1545         }
1546 #endif
1547         return ret;
1548 }
1549
1550 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
1551                                           struct btrfs_fs_info *fs_info,
1552                                           struct btrfs_path *path,
1553                                           u64 bytenr, u64 parent,
1554                                           u64 root_objectid)
1555 {
1556         struct btrfs_key key;
1557         int ret;
1558
1559         key.objectid = bytenr;
1560         if (parent) {
1561                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
1562                 key.offset = parent;
1563         } else {
1564                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
1565                 key.offset = root_objectid;
1566         }
1567
1568         ret = btrfs_insert_empty_item(trans, fs_info->extent_root,
1569                                       path, &key, 0);
1570         btrfs_release_path(path);
1571         return ret;
1572 }
1573
1574 static inline int extent_ref_type(u64 parent, u64 owner)
1575 {
1576         int type;
1577         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1578                 if (parent > 0)
1579                         type = BTRFS_SHARED_BLOCK_REF_KEY;
1580                 else
1581                         type = BTRFS_TREE_BLOCK_REF_KEY;
1582         } else {
1583                 if (parent > 0)
1584                         type = BTRFS_SHARED_DATA_REF_KEY;
1585                 else
1586                         type = BTRFS_EXTENT_DATA_REF_KEY;
1587         }
1588         return type;
1589 }
1590
1591 static int find_next_key(struct btrfs_path *path, int level,
1592                          struct btrfs_key *key)
1593
1594 {
1595         for (; level < BTRFS_MAX_LEVEL; level++) {
1596                 if (!path->nodes[level])
1597                         break;
1598                 if (path->slots[level] + 1 >=
1599                     btrfs_header_nritems(path->nodes[level]))
1600                         continue;
1601                 if (level == 0)
1602                         btrfs_item_key_to_cpu(path->nodes[level], key,
1603                                               path->slots[level] + 1);
1604                 else
1605                         btrfs_node_key_to_cpu(path->nodes[level], key,
1606                                               path->slots[level] + 1);
1607                 return 0;
1608         }
1609         return 1;
1610 }
1611
1612 /*
1613  * look for inline back ref. if back ref is found, *ref_ret is set
1614  * to the address of inline back ref, and 0 is returned.
1615  *
1616  * if back ref isn't found, *ref_ret is set to the address where it
1617  * should be inserted, and -ENOENT is returned.
1618  *
1619  * if insert is true and there are too many inline back refs, the path
1620  * points to the extent item, and -EAGAIN is returned.
1621  *
1622  * NOTE: inline back refs are ordered in the same way that back ref
1623  *       items in the tree are ordered.
1624  */
1625 static noinline_for_stack
1626 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
1627                                  struct btrfs_fs_info *fs_info,
1628                                  struct btrfs_path *path,
1629                                  struct btrfs_extent_inline_ref **ref_ret,
1630                                  u64 bytenr, u64 num_bytes,
1631                                  u64 parent, u64 root_objectid,
1632                                  u64 owner, u64 offset, int insert)
1633 {
1634         struct btrfs_root *root = fs_info->extent_root;
1635         struct btrfs_key key;
1636         struct extent_buffer *leaf;
1637         struct btrfs_extent_item *ei;
1638         struct btrfs_extent_inline_ref *iref;
1639         u64 flags;
1640         u64 item_size;
1641         unsigned long ptr;
1642         unsigned long end;
1643         int extra_size;
1644         int type;
1645         int want;
1646         int ret;
1647         int err = 0;
1648         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
1649         int needed;
1650
1651         key.objectid = bytenr;
1652         key.type = BTRFS_EXTENT_ITEM_KEY;
1653         key.offset = num_bytes;
1654
1655         want = extent_ref_type(parent, owner);
1656         if (insert) {
1657                 extra_size = btrfs_extent_inline_ref_size(want);
1658                 path->keep_locks = 1;
1659         } else
1660                 extra_size = -1;
1661
1662         /*
1663          * Owner is our parent level, so we can just add one to get the level
1664          * for the block we are interested in.
1665          */
1666         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
1667                 key.type = BTRFS_METADATA_ITEM_KEY;
1668                 key.offset = owner;
1669         }
1670
1671 again:
1672         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
1673         if (ret < 0) {
1674                 err = ret;
1675                 goto out;
1676         }
1677
1678         /*
1679          * We may be a newly converted file system which still has the old fat
1680          * extent entries for metadata, so try and see if we have one of those.
1681          */
1682         if (ret > 0 && skinny_metadata) {
1683                 skinny_metadata = false;
1684                 if (path->slots[0]) {
1685                         path->slots[0]--;
1686                         btrfs_item_key_to_cpu(path->nodes[0], &key,
1687                                               path->slots[0]);
1688                         if (key.objectid == bytenr &&
1689                             key.type == BTRFS_EXTENT_ITEM_KEY &&
1690                             key.offset == num_bytes)
1691                                 ret = 0;
1692                 }
1693                 if (ret) {
1694                         key.objectid = bytenr;
1695                         key.type = BTRFS_EXTENT_ITEM_KEY;
1696                         key.offset = num_bytes;
1697                         btrfs_release_path(path);
1698                         goto again;
1699                 }
1700         }
1701
1702         if (ret && !insert) {
1703                 err = -ENOENT;
1704                 goto out;
1705         } else if (WARN_ON(ret)) {
1706                 btrfs_print_leaf(path->nodes[0]);
1707                 btrfs_err(fs_info,
1708 "extent item not found for insert, bytenr %llu num_bytes %llu parent %llu root_objectid %llu owner %llu offset %llu",
1709                           bytenr, num_bytes, parent, root_objectid, owner,
1710                           offset);
1711                 err = -EIO;
1712                 goto out;
1713         }
1714
1715         leaf = path->nodes[0];
1716         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1717 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
1718         if (item_size < sizeof(*ei)) {
1719                 if (!insert) {
1720                         err = -ENOENT;
1721                         goto out;
1722                 }
1723                 ret = convert_extent_item_v0(trans, fs_info, path, owner,
1724                                              extra_size);
1725                 if (ret < 0) {
1726                         err = ret;
1727                         goto out;
1728                 }
1729                 leaf = path->nodes[0];
1730                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1731         }
1732 #endif
1733         BUG_ON(item_size < sizeof(*ei));
1734
1735         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1736         flags = btrfs_extent_flags(leaf, ei);
1737
1738         ptr = (unsigned long)(ei + 1);
1739         end = (unsigned long)ei + item_size;
1740
1741         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
1742                 ptr += sizeof(struct btrfs_tree_block_info);
1743                 BUG_ON(ptr > end);
1744         }
1745
1746         if (owner >= BTRFS_FIRST_FREE_OBJECTID)
1747                 needed = BTRFS_REF_TYPE_DATA;
1748         else
1749                 needed = BTRFS_REF_TYPE_BLOCK;
1750
1751         err = -ENOENT;
1752         while (1) {
1753                 if (ptr >= end) {
1754                         WARN_ON(ptr > end);
1755                         break;
1756                 }
1757                 iref = (struct btrfs_extent_inline_ref *)ptr;
1758                 type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
1759                 if (type == BTRFS_REF_TYPE_INVALID) {
1760                         err = -EINVAL;
1761                         goto out;
1762                 }
1763
1764                 if (want < type)
1765                         break;
1766                 if (want > type) {
1767                         ptr += btrfs_extent_inline_ref_size(type);
1768                         continue;
1769                 }
1770
1771                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1772                         struct btrfs_extent_data_ref *dref;
1773                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1774                         if (match_extent_data_ref(leaf, dref, root_objectid,
1775                                                   owner, offset)) {
1776                                 err = 0;
1777                                 break;
1778                         }
1779                         if (hash_extent_data_ref_item(leaf, dref) <
1780                             hash_extent_data_ref(root_objectid, owner, offset))
1781                                 break;
1782                 } else {
1783                         u64 ref_offset;
1784                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
1785                         if (parent > 0) {
1786                                 if (parent == ref_offset) {
1787                                         err = 0;
1788                                         break;
1789                                 }
1790                                 if (ref_offset < parent)
1791                                         break;
1792                         } else {
1793                                 if (root_objectid == ref_offset) {
1794                                         err = 0;
1795                                         break;
1796                                 }
1797                                 if (ref_offset < root_objectid)
1798                                         break;
1799                         }
1800                 }
1801                 ptr += btrfs_extent_inline_ref_size(type);
1802         }
1803         if (err == -ENOENT && insert) {
1804                 if (item_size + extra_size >=
1805                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
1806                         err = -EAGAIN;
1807                         goto out;
1808                 }
1809                 /*
1810                  * To add new inline back ref, we have to make sure
1811                  * there is no corresponding back ref item.
1812                  * For simplicity, we just do not add new inline back
1813                  * ref if there is any kind of item for this block
1814                  */
1815                 if (find_next_key(path, 0, &key) == 0 &&
1816                     key.objectid == bytenr &&
1817                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
1818                         err = -EAGAIN;
1819                         goto out;
1820                 }
1821         }
1822         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
1823 out:
1824         if (insert) {
1825                 path->keep_locks = 0;
1826                 btrfs_unlock_up_safe(path, 1);
1827         }
1828         return err;
1829 }
1830
1831 /*
1832  * helper to add new inline back ref
1833  */
1834 static noinline_for_stack
1835 void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
1836                                  struct btrfs_path *path,
1837                                  struct btrfs_extent_inline_ref *iref,
1838                                  u64 parent, u64 root_objectid,
1839                                  u64 owner, u64 offset, int refs_to_add,
1840                                  struct btrfs_delayed_extent_op *extent_op)
1841 {
1842         struct extent_buffer *leaf;
1843         struct btrfs_extent_item *ei;
1844         unsigned long ptr;
1845         unsigned long end;
1846         unsigned long item_offset;
1847         u64 refs;
1848         int size;
1849         int type;
1850
1851         leaf = path->nodes[0];
1852         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1853         item_offset = (unsigned long)iref - (unsigned long)ei;
1854
1855         type = extent_ref_type(parent, owner);
1856         size = btrfs_extent_inline_ref_size(type);
1857
1858         btrfs_extend_item(fs_info, path, size);
1859
1860         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1861         refs = btrfs_extent_refs(leaf, ei);
1862         refs += refs_to_add;
1863         btrfs_set_extent_refs(leaf, ei, refs);
1864         if (extent_op)
1865                 __run_delayed_extent_op(extent_op, leaf, ei);
1866
1867         ptr = (unsigned long)ei + item_offset;
1868         end = (unsigned long)ei + btrfs_item_size_nr(leaf, path->slots[0]);
1869         if (ptr < end - size)
1870                 memmove_extent_buffer(leaf, ptr + size, ptr,
1871                                       end - size - ptr);
1872
1873         iref = (struct btrfs_extent_inline_ref *)ptr;
1874         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1875         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1876                 struct btrfs_extent_data_ref *dref;
1877                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1878                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1879                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1880                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1881                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1882         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1883                 struct btrfs_shared_data_ref *sref;
1884                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1885                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1886                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1887         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1888                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1889         } else {
1890                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1891         }
1892         btrfs_mark_buffer_dirty(leaf);
1893 }
1894
1895 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1896                                  struct btrfs_fs_info *fs_info,
1897                                  struct btrfs_path *path,
1898                                  struct btrfs_extent_inline_ref **ref_ret,
1899                                  u64 bytenr, u64 num_bytes, u64 parent,
1900                                  u64 root_objectid, u64 owner, u64 offset)
1901 {
1902         int ret;
1903
1904         ret = lookup_inline_extent_backref(trans, fs_info, path, ref_ret,
1905                                            bytenr, num_bytes, parent,
1906                                            root_objectid, owner, offset, 0);
1907         if (ret != -ENOENT)
1908                 return ret;
1909
1910         btrfs_release_path(path);
1911         *ref_ret = NULL;
1912
1913         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1914                 ret = lookup_tree_block_ref(trans, fs_info, path, bytenr,
1915                                             parent, root_objectid);
1916         } else {
1917                 ret = lookup_extent_data_ref(trans, fs_info, path, bytenr,
1918                                              parent, root_objectid, owner,
1919                                              offset);
1920         }
1921         return ret;
1922 }
1923
1924 /*
1925  * helper to update/remove inline back ref
1926  */
1927 static noinline_for_stack
1928 void update_inline_extent_backref(struct btrfs_fs_info *fs_info,
1929                                   struct btrfs_path *path,
1930                                   struct btrfs_extent_inline_ref *iref,
1931                                   int refs_to_mod,
1932                                   struct btrfs_delayed_extent_op *extent_op,
1933                                   int *last_ref)
1934 {
1935         struct extent_buffer *leaf;
1936         struct btrfs_extent_item *ei;
1937         struct btrfs_extent_data_ref *dref = NULL;
1938         struct btrfs_shared_data_ref *sref = NULL;
1939         unsigned long ptr;
1940         unsigned long end;
1941         u32 item_size;
1942         int size;
1943         int type;
1944         u64 refs;
1945
1946         leaf = path->nodes[0];
1947         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1948         refs = btrfs_extent_refs(leaf, ei);
1949         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1950         refs += refs_to_mod;
1951         btrfs_set_extent_refs(leaf, ei, refs);
1952         if (extent_op)
1953                 __run_delayed_extent_op(extent_op, leaf, ei);
1954
1955         /*
1956          * If type is invalid, we should have bailed out after
1957          * lookup_inline_extent_backref().
1958          */
1959         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
1960         ASSERT(type != BTRFS_REF_TYPE_INVALID);
1961
1962         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1963                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1964                 refs = btrfs_extent_data_ref_count(leaf, dref);
1965         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1966                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1967                 refs = btrfs_shared_data_ref_count(leaf, sref);
1968         } else {
1969                 refs = 1;
1970                 BUG_ON(refs_to_mod != -1);
1971         }
1972
1973         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1974         refs += refs_to_mod;
1975
1976         if (refs > 0) {
1977                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1978                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1979                 else
1980                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1981         } else {
1982                 *last_ref = 1;
1983                 size =  btrfs_extent_inline_ref_size(type);
1984                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
1985                 ptr = (unsigned long)iref;
1986                 end = (unsigned long)ei + item_size;
1987                 if (ptr + size < end)
1988                         memmove_extent_buffer(leaf, ptr, ptr + size,
1989                                               end - ptr - size);
1990                 item_size -= size;
1991                 btrfs_truncate_item(fs_info, path, item_size, 1);
1992         }
1993         btrfs_mark_buffer_dirty(leaf);
1994 }
1995
1996 static noinline_for_stack
1997 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1998                                  struct btrfs_fs_info *fs_info,
1999                                  struct btrfs_path *path,
2000                                  u64 bytenr, u64 num_bytes, u64 parent,
2001                                  u64 root_objectid, u64 owner,
2002                                  u64 offset, int refs_to_add,
2003                                  struct btrfs_delayed_extent_op *extent_op)
2004 {
2005         struct btrfs_extent_inline_ref *iref;
2006         int ret;
2007
2008         ret = lookup_inline_extent_backref(trans, fs_info, path, &iref,
2009                                            bytenr, num_bytes, parent,
2010                                            root_objectid, owner, offset, 1);
2011         if (ret == 0) {
2012                 BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
2013                 update_inline_extent_backref(fs_info, path, iref,
2014                                              refs_to_add, extent_op, NULL);
2015         } else if (ret == -ENOENT) {
2016                 setup_inline_extent_backref(fs_info, path, iref, parent,
2017                                             root_objectid, owner, offset,
2018                                             refs_to_add, extent_op);
2019                 ret = 0;
2020         }
2021         return ret;
2022 }
2023
2024 static int insert_extent_backref(struct btrfs_trans_handle *trans,
2025                                  struct btrfs_fs_info *fs_info,
2026                                  struct btrfs_path *path,
2027                                  u64 bytenr, u64 parent, u64 root_objectid,
2028                                  u64 owner, u64 offset, int refs_to_add)
2029 {
2030         int ret;
2031         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2032                 BUG_ON(refs_to_add != 1);
2033                 ret = insert_tree_block_ref(trans, fs_info, path, bytenr,
2034                                             parent, root_objectid);
2035         } else {
2036                 ret = insert_extent_data_ref(trans, fs_info, path, bytenr,
2037                                              parent, root_objectid,
2038                                              owner, offset, refs_to_add);
2039         }
2040         return ret;
2041 }
2042
2043 static int remove_extent_backref(struct btrfs_trans_handle *trans,
2044                                  struct btrfs_fs_info *fs_info,
2045                                  struct btrfs_path *path,
2046                                  struct btrfs_extent_inline_ref *iref,
2047                                  int refs_to_drop, int is_data, int *last_ref)
2048 {
2049         int ret = 0;
2050
2051         BUG_ON(!is_data && refs_to_drop != 1);
2052         if (iref) {
2053                 update_inline_extent_backref(fs_info, path, iref,
2054                                              -refs_to_drop, NULL, last_ref);
2055         } else if (is_data) {
2056                 ret = remove_extent_data_ref(trans, fs_info, path, refs_to_drop,
2057                                              last_ref);
2058         } else {
2059                 *last_ref = 1;
2060                 ret = btrfs_del_item(trans, fs_info->extent_root, path);
2061         }
2062         return ret;
2063 }
2064
2065 #define in_range(b, first, len)        ((b) >= (first) && (b) < (first) + (len))
2066 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
2067                                u64 *discarded_bytes)
2068 {
2069         int j, ret = 0;
2070         u64 bytes_left, end;
2071         u64 aligned_start = ALIGN(start, 1 << 9);
2072
2073         if (WARN_ON(start != aligned_start)) {
2074                 len -= aligned_start - start;
2075                 len = round_down(len, 1 << 9);
2076                 start = aligned_start;
2077         }
2078
2079         *discarded_bytes = 0;
2080
2081         if (!len)
2082                 return 0;
2083
2084         end = start + len;
2085         bytes_left = len;
2086
2087         /* Skip any superblocks on this device. */
2088         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
2089                 u64 sb_start = btrfs_sb_offset(j);
2090                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
2091                 u64 size = sb_start - start;
2092
2093                 if (!in_range(sb_start, start, bytes_left) &&
2094                     !in_range(sb_end, start, bytes_left) &&
2095                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
2096                         continue;
2097
2098                 /*
2099                  * Superblock spans beginning of range.  Adjust start and
2100                  * try again.
2101                  */
2102                 if (sb_start <= start) {
2103                         start += sb_end - start;
2104                         if (start > end) {
2105                                 bytes_left = 0;
2106                                 break;
2107                         }
2108                         bytes_left = end - start;
2109                         continue;
2110                 }
2111
2112                 if (size) {
2113                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
2114                                                    GFP_NOFS, 0);
2115                         if (!ret)
2116                                 *discarded_bytes += size;
2117                         else if (ret != -EOPNOTSUPP)
2118                                 return ret;
2119                 }
2120
2121                 start = sb_end;
2122                 if (start > end) {
2123                         bytes_left = 0;
2124                         break;
2125                 }
2126                 bytes_left = end - start;
2127         }
2128
2129         if (bytes_left) {
2130                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
2131                                            GFP_NOFS, 0);
2132                 if (!ret)
2133                         *discarded_bytes += bytes_left;
2134         }
2135         return ret;
2136 }
2137
2138 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
2139                          u64 num_bytes, u64 *actual_bytes)
2140 {
2141         int ret;
2142         u64 discarded_bytes = 0;
2143         struct btrfs_bio *bbio = NULL;
2144
2145
2146         /*
2147          * Avoid races with device replace and make sure our bbio has devices
2148          * associated to its stripes that don't go away while we are discarding.
2149          */
2150         btrfs_bio_counter_inc_blocked(fs_info);
2151         /* Tell the block device(s) that the sectors can be discarded */
2152         ret = btrfs_map_block(fs_info, BTRFS_MAP_DISCARD, bytenr, &num_bytes,
2153                               &bbio, 0);
2154         /* Error condition is -ENOMEM */
2155         if (!ret) {
2156                 struct btrfs_bio_stripe *stripe = bbio->stripes;
2157                 int i;
2158
2159
2160                 for (i = 0; i < bbio->num_stripes; i++, stripe++) {
2161                         u64 bytes;
2162                         if (!stripe->dev->can_discard)
2163                                 continue;
2164
2165                         ret = btrfs_issue_discard(stripe->dev->bdev,
2166                                                   stripe->physical,
2167                                                   stripe->length,
2168                                                   &bytes);
2169                         if (!ret)
2170                                 discarded_bytes += bytes;
2171                         else if (ret != -EOPNOTSUPP)
2172                                 break; /* Logic errors or -ENOMEM, or -EIO but I don't know how that could happen JDM */
2173
2174                         /*
2175                          * Just in case we get back EOPNOTSUPP for some reason,
2176                          * just ignore the return value so we don't screw up
2177                          * people calling discard_extent.
2178                          */
2179                         ret = 0;
2180                 }
2181                 btrfs_put_bbio(bbio);
2182         }
2183         btrfs_bio_counter_dec(fs_info);
2184
2185         if (actual_bytes)
2186                 *actual_bytes = discarded_bytes;
2187
2188
2189         if (ret == -EOPNOTSUPP)
2190                 ret = 0;
2191         return ret;
2192 }
2193
2194 /* Can return -ENOMEM */
2195 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2196                          struct btrfs_fs_info *fs_info,
2197                          u64 bytenr, u64 num_bytes, u64 parent,
2198                          u64 root_objectid, u64 owner, u64 offset)
2199 {
2200         int old_ref_mod, new_ref_mod;
2201         int ret;
2202
2203         BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID &&
2204                root_objectid == BTRFS_TREE_LOG_OBJECTID);
2205
2206         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
2207                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
2208                                                  num_bytes, parent,
2209                                                  root_objectid, (int)owner,
2210                                                  BTRFS_ADD_DELAYED_REF, NULL,
2211                                                  &old_ref_mod, &new_ref_mod);
2212         } else {
2213                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
2214                                                  num_bytes, parent,
2215                                                  root_objectid, owner, offset,
2216                                                  0, BTRFS_ADD_DELAYED_REF,
2217                                                  &old_ref_mod, &new_ref_mod);
2218         }
2219
2220         if (ret == 0 && old_ref_mod < 0 && new_ref_mod >= 0)
2221                 add_pinned_bytes(fs_info, -num_bytes, owner, root_objectid);
2222
2223         return ret;
2224 }
2225
2226 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
2227                                   struct btrfs_fs_info *fs_info,
2228                                   struct btrfs_delayed_ref_node *node,
2229                                   u64 parent, u64 root_objectid,
2230                                   u64 owner, u64 offset, int refs_to_add,
2231                                   struct btrfs_delayed_extent_op *extent_op)
2232 {
2233         struct btrfs_path *path;
2234         struct extent_buffer *leaf;
2235         struct btrfs_extent_item *item;
2236         struct btrfs_key key;
2237         u64 bytenr = node->bytenr;
2238         u64 num_bytes = node->num_bytes;
2239         u64 refs;
2240         int ret;
2241
2242         path = btrfs_alloc_path();
2243         if (!path)
2244                 return -ENOMEM;
2245
2246         path->reada = READA_FORWARD;
2247         path->leave_spinning = 1;
2248         /* this will setup the path even if it fails to insert the back ref */
2249         ret = insert_inline_extent_backref(trans, fs_info, path, bytenr,
2250                                            num_bytes, parent, root_objectid,
2251                                            owner, offset,
2252                                            refs_to_add, extent_op);
2253         if ((ret < 0 && ret != -EAGAIN) || !ret)
2254                 goto out;
2255
2256         /*
2257          * Ok we had -EAGAIN which means we didn't have space to insert and
2258          * inline extent ref, so just update the reference count and add a
2259          * normal backref.
2260          */
2261         leaf = path->nodes[0];
2262         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2263         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2264         refs = btrfs_extent_refs(leaf, item);
2265         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
2266         if (extent_op)
2267                 __run_delayed_extent_op(extent_op, leaf, item);
2268
2269         btrfs_mark_buffer_dirty(leaf);
2270         btrfs_release_path(path);
2271
2272         path->reada = READA_FORWARD;
2273         path->leave_spinning = 1;
2274         /* now insert the actual backref */
2275         ret = insert_extent_backref(trans, fs_info, path, bytenr, parent,
2276                                     root_objectid, owner, offset, refs_to_add);
2277         if (ret)
2278                 btrfs_abort_transaction(trans, ret);
2279 out:
2280         btrfs_free_path(path);
2281         return ret;
2282 }
2283
2284 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
2285                                 struct btrfs_fs_info *fs_info,
2286                                 struct btrfs_delayed_ref_node *node,
2287                                 struct btrfs_delayed_extent_op *extent_op,
2288                                 int insert_reserved)
2289 {
2290         int ret = 0;
2291         struct btrfs_delayed_data_ref *ref;
2292         struct btrfs_key ins;
2293         u64 parent = 0;
2294         u64 ref_root = 0;
2295         u64 flags = 0;
2296
2297         ins.objectid = node->bytenr;
2298         ins.offset = node->num_bytes;
2299         ins.type = BTRFS_EXTENT_ITEM_KEY;
2300
2301         ref = btrfs_delayed_node_to_data_ref(node);
2302         trace_run_delayed_data_ref(fs_info, node, ref, node->action);
2303
2304         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
2305                 parent = ref->parent;
2306         ref_root = ref->root;
2307
2308         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2309                 if (extent_op)
2310                         flags |= extent_op->flags_to_set;
2311                 ret = alloc_reserved_file_extent(trans, fs_info,
2312                                                  parent, ref_root, flags,
2313                                                  ref->objectid, ref->offset,
2314                                                  &ins, node->ref_mod);
2315         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2316                 ret = __btrfs_inc_extent_ref(trans, fs_info, node, parent,
2317                                              ref_root, ref->objectid,
2318                                              ref->offset, node->ref_mod,
2319                                              extent_op);
2320         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2321                 ret = __btrfs_free_extent(trans, fs_info, node, parent,
2322                                           ref_root, ref->objectid,
2323                                           ref->offset, node->ref_mod,
2324                                           extent_op);
2325         } else {
2326                 BUG();
2327         }
2328         return ret;
2329 }
2330
2331 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
2332                                     struct extent_buffer *leaf,
2333                                     struct btrfs_extent_item *ei)
2334 {
2335         u64 flags = btrfs_extent_flags(leaf, ei);
2336         if (extent_op->update_flags) {
2337                 flags |= extent_op->flags_to_set;
2338                 btrfs_set_extent_flags(leaf, ei, flags);
2339         }
2340
2341         if (extent_op->update_key) {
2342                 struct btrfs_tree_block_info *bi;
2343                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
2344                 bi = (struct btrfs_tree_block_info *)(ei + 1);
2345                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
2346         }
2347 }
2348
2349 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
2350                                  struct btrfs_fs_info *fs_info,
2351                                  struct btrfs_delayed_ref_node *node,
2352                                  struct btrfs_delayed_extent_op *extent_op)
2353 {
2354         struct btrfs_key key;
2355         struct btrfs_path *path;
2356         struct btrfs_extent_item *ei;
2357         struct extent_buffer *leaf;
2358         u32 item_size;
2359         int ret;
2360         int err = 0;
2361         int metadata = !extent_op->is_data;
2362
2363         if (trans->aborted)
2364                 return 0;
2365
2366         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2367                 metadata = 0;
2368
2369         path = btrfs_alloc_path();
2370         if (!path)
2371                 return -ENOMEM;
2372
2373         key.objectid = node->bytenr;
2374
2375         if (metadata) {
2376                 key.type = BTRFS_METADATA_ITEM_KEY;
2377                 key.offset = extent_op->level;
2378         } else {
2379                 key.type = BTRFS_EXTENT_ITEM_KEY;
2380                 key.offset = node->num_bytes;
2381         }
2382
2383 again:
2384         path->reada = READA_FORWARD;
2385         path->leave_spinning = 1;
2386         ret = btrfs_search_slot(trans, fs_info->extent_root, &key, path, 0, 1);
2387         if (ret < 0) {
2388                 err = ret;
2389                 goto out;
2390         }
2391         if (ret > 0) {
2392                 if (metadata) {
2393                         if (path->slots[0] > 0) {
2394                                 path->slots[0]--;
2395                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
2396                                                       path->slots[0]);
2397                                 if (key.objectid == node->bytenr &&
2398                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
2399                                     key.offset == node->num_bytes)
2400                                         ret = 0;
2401                         }
2402                         if (ret > 0) {
2403                                 btrfs_release_path(path);
2404                                 metadata = 0;
2405
2406                                 key.objectid = node->bytenr;
2407                                 key.offset = node->num_bytes;
2408                                 key.type = BTRFS_EXTENT_ITEM_KEY;
2409                                 goto again;
2410                         }
2411                 } else {
2412                         err = -EIO;
2413                         goto out;
2414                 }
2415         }
2416
2417         leaf = path->nodes[0];
2418         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2419 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
2420         if (item_size < sizeof(*ei)) {
2421                 ret = convert_extent_item_v0(trans, fs_info, path, (u64)-1, 0);
2422                 if (ret < 0) {
2423                         err = ret;
2424                         goto out;
2425                 }
2426                 leaf = path->nodes[0];
2427                 item_size = btrfs_item_size_nr(leaf, path->slots[0]);
2428         }
2429 #endif
2430         BUG_ON(item_size < sizeof(*ei));
2431         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2432         __run_delayed_extent_op(extent_op, leaf, ei);
2433
2434         btrfs_mark_buffer_dirty(leaf);
2435 out:
2436         btrfs_free_path(path);
2437         return err;
2438 }
2439
2440 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
2441                                 struct btrfs_fs_info *fs_info,
2442                                 struct btrfs_delayed_ref_node *node,
2443                                 struct btrfs_delayed_extent_op *extent_op,
2444                                 int insert_reserved)
2445 {
2446         int ret = 0;
2447         struct btrfs_delayed_tree_ref *ref;
2448         struct btrfs_key ins;
2449         u64 parent = 0;
2450         u64 ref_root = 0;
2451         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
2452
2453         ref = btrfs_delayed_node_to_tree_ref(node);
2454         trace_run_delayed_tree_ref(fs_info, node, ref, node->action);
2455
2456         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2457                 parent = ref->parent;
2458         ref_root = ref->root;
2459
2460         ins.objectid = node->bytenr;
2461         if (skinny_metadata) {
2462                 ins.offset = ref->level;
2463                 ins.type = BTRFS_METADATA_ITEM_KEY;
2464         } else {
2465                 ins.offset = node->num_bytes;
2466                 ins.type = BTRFS_EXTENT_ITEM_KEY;
2467         }
2468
2469         if (node->ref_mod != 1) {
2470                 btrfs_err(fs_info,
2471         "btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
2472                           node->bytenr, node->ref_mod, node->action, ref_root,
2473                           parent);
2474                 return -EIO;
2475         }
2476         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
2477                 BUG_ON(!extent_op || !extent_op->update_flags);
2478                 ret = alloc_reserved_tree_block(trans, fs_info,
2479                                                 parent, ref_root,
2480                                                 extent_op->flags_to_set,
2481                                                 &extent_op->key,
2482                                                 ref->level, &ins);
2483         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
2484                 ret = __btrfs_inc_extent_ref(trans, fs_info, node,
2485                                              parent, ref_root,
2486                                              ref->level, 0, 1,
2487                                              extent_op);
2488         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
2489                 ret = __btrfs_free_extent(trans, fs_info, node,
2490                                           parent, ref_root,
2491                                           ref->level, 0, 1, extent_op);
2492         } else {
2493                 BUG();
2494         }
2495         return ret;
2496 }
2497
2498 /* helper function to actually process a single delayed ref entry */
2499 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
2500                                struct btrfs_fs_info *fs_info,
2501                                struct btrfs_delayed_ref_node *node,
2502                                struct btrfs_delayed_extent_op *extent_op,
2503                                int insert_reserved)
2504 {
2505         int ret = 0;
2506
2507         if (trans->aborted) {
2508                 if (insert_reserved)
2509                         btrfs_pin_extent(fs_info, node->bytenr,
2510                                          node->num_bytes, 1);
2511                 return 0;
2512         }
2513
2514         if (btrfs_delayed_ref_is_head(node)) {
2515                 struct btrfs_delayed_ref_head *head;
2516                 /*
2517                  * we've hit the end of the chain and we were supposed
2518                  * to insert this extent into the tree.  But, it got
2519                  * deleted before we ever needed to insert it, so all
2520                  * we have to do is clean up the accounting
2521                  */
2522                 BUG_ON(extent_op);
2523                 head = btrfs_delayed_node_to_head(node);
2524                 trace_run_delayed_ref_head(fs_info, node, head, node->action);
2525
2526                 if (head->total_ref_mod < 0) {
2527                         struct btrfs_block_group_cache *cache;
2528
2529                         cache = btrfs_lookup_block_group(fs_info, node->bytenr);
2530                         ASSERT(cache);
2531                         percpu_counter_add(&cache->space_info->total_bytes_pinned,
2532                                            -node->num_bytes);
2533                         btrfs_put_block_group(cache);
2534                 }
2535
2536                 if (insert_reserved) {
2537                         btrfs_pin_extent(fs_info, node->bytenr,
2538                                          node->num_bytes, 1);
2539                         if (head->is_data) {
2540                                 ret = btrfs_del_csums(trans, fs_info,
2541                                                       node->bytenr,
2542                                                       node->num_bytes);
2543                         }
2544                 }
2545
2546                 /* Also free its reserved qgroup space */
2547                 btrfs_qgroup_free_delayed_ref(fs_info, head->qgroup_ref_root,
2548                                               head->qgroup_reserved);
2549                 return ret;
2550         }
2551
2552         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
2553             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
2554                 ret = run_delayed_tree_ref(trans, fs_info, node, extent_op,
2555                                            insert_reserved);
2556         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
2557                  node->type == BTRFS_SHARED_DATA_REF_KEY)
2558                 ret = run_delayed_data_ref(trans, fs_info, node, extent_op,
2559                                            insert_reserved);
2560         else
2561                 BUG();
2562         return ret;
2563 }
2564
2565 static inline struct btrfs_delayed_ref_node *
2566 select_delayed_ref(struct btrfs_delayed_ref_head *head)
2567 {
2568         struct btrfs_delayed_ref_node *ref;
2569
2570         if (list_empty(&head->ref_list))
2571                 return NULL;
2572
2573         /*
2574          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
2575          * This is to prevent a ref count from going down to zero, which deletes
2576          * the extent item from the extent tree, when there still are references
2577          * to add, which would fail because they would not find the extent item.
2578          */
2579         if (!list_empty(&head->ref_add_list))
2580                 return list_first_entry(&head->ref_add_list,
2581                                 struct btrfs_delayed_ref_node, add_list);
2582
2583         ref = list_first_entry(&head->ref_list, struct btrfs_delayed_ref_node,
2584                                list);
2585         ASSERT(list_empty(&ref->add_list));
2586         return ref;
2587 }
2588
2589 /*
2590  * Returns 0 on success or if called with an already aborted transaction.
2591  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
2592  */
2593 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2594                                              struct btrfs_fs_info *fs_info,
2595                                              unsigned long nr)
2596 {
2597         struct btrfs_delayed_ref_root *delayed_refs;
2598         struct btrfs_delayed_ref_node *ref;
2599         struct btrfs_delayed_ref_head *locked_ref = NULL;
2600         struct btrfs_delayed_extent_op *extent_op;
2601         ktime_t start = ktime_get();
2602         int ret;
2603         unsigned long count = 0;
2604         unsigned long actual_count = 0;
2605         int must_insert_reserved = 0;
2606
2607         delayed_refs = &trans->transaction->delayed_refs;
2608         while (1) {
2609                 if (!locked_ref) {
2610                         if (count >= nr)
2611                                 break;
2612
2613                         spin_lock(&delayed_refs->lock);
2614                         locked_ref = btrfs_select_ref_head(trans);
2615                         if (!locked_ref) {
2616                                 spin_unlock(&delayed_refs->lock);
2617                                 break;
2618                         }
2619
2620                         /* grab the lock that says we are going to process
2621                          * all the refs for this head */
2622                         ret = btrfs_delayed_ref_lock(trans, locked_ref);
2623                         spin_unlock(&delayed_refs->lock);
2624                         /*
2625                          * we may have dropped the spin lock to get the head
2626                          * mutex lock, and that might have given someone else
2627                          * time to free the head.  If that's true, it has been
2628                          * removed from our list and we can move on.
2629                          */
2630                         if (ret == -EAGAIN) {
2631                                 locked_ref = NULL;
2632                                 count++;
2633                                 continue;
2634                         }
2635                 }
2636
2637                 /*
2638                  * We need to try and merge add/drops of the same ref since we
2639                  * can run into issues with relocate dropping the implicit ref
2640                  * and then it being added back again before the drop can
2641                  * finish.  If we merged anything we need to re-loop so we can
2642                  * get a good ref.
2643                  * Or we can get node references of the same type that weren't
2644                  * merged when created due to bumps in the tree mod seq, and
2645                  * we need to merge them to prevent adding an inline extent
2646                  * backref before dropping it (triggering a BUG_ON at
2647                  * insert_inline_extent_backref()).
2648                  */
2649                 spin_lock(&locked_ref->lock);
2650                 btrfs_merge_delayed_refs(trans, fs_info, delayed_refs,
2651                                          locked_ref);
2652
2653                 /*
2654                  * locked_ref is the head node, so we have to go one
2655                  * node back for any delayed ref updates
2656                  */
2657                 ref = select_delayed_ref(locked_ref);
2658
2659                 if (ref && ref->seq &&
2660                     btrfs_check_delayed_seq(fs_info, delayed_refs, ref->seq)) {
2661                         spin_unlock(&locked_ref->lock);
2662                         spin_lock(&delayed_refs->lock);
2663                         locked_ref->processing = 0;
2664                         delayed_refs->num_heads_ready++;
2665                         spin_unlock(&delayed_refs->lock);
2666                         btrfs_delayed_ref_unlock(locked_ref);
2667                         locked_ref = NULL;
2668                         cond_resched();
2669                         count++;
2670                         continue;
2671                 }
2672
2673                 /*
2674                  * record the must insert reserved flag before we
2675                  * drop the spin lock.
2676                  */
2677                 must_insert_reserved = locked_ref->must_insert_reserved;
2678                 locked_ref->must_insert_reserved = 0;
2679
2680                 extent_op = locked_ref->extent_op;
2681                 locked_ref->extent_op = NULL;
2682
2683                 if (!ref) {
2684
2685
2686                         /* All delayed refs have been processed, Go ahead
2687                          * and send the head node to run_one_delayed_ref,
2688                          * so that any accounting fixes can happen
2689                          */
2690                         ref = &locked_ref->node;
2691
2692                         if (extent_op && must_insert_reserved) {
2693                                 btrfs_free_delayed_extent_op(extent_op);
2694                                 extent_op = NULL;
2695                         }
2696
2697                         if (extent_op) {
2698                                 spin_unlock(&locked_ref->lock);
2699                                 ret = run_delayed_extent_op(trans, fs_info,
2700                                                             ref, extent_op);
2701                                 btrfs_free_delayed_extent_op(extent_op);
2702
2703                                 if (ret) {
2704                                         /*
2705                                          * Need to reset must_insert_reserved if
2706                                          * there was an error so the abort stuff
2707                                          * can cleanup the reserved space
2708                                          * properly.
2709                                          */
2710                                         if (must_insert_reserved)
2711                                                 locked_ref->must_insert_reserved = 1;
2712                                         spin_lock(&delayed_refs->lock);
2713                                         locked_ref->processing = 0;
2714                                         delayed_refs->num_heads_ready++;
2715                                         spin_unlock(&delayed_refs->lock);
2716                                         btrfs_debug(fs_info,
2717                                                     "run_delayed_extent_op returned %d",
2718                                                     ret);
2719                                         btrfs_delayed_ref_unlock(locked_ref);
2720                                         return ret;
2721                                 }
2722                                 continue;
2723                         }
2724
2725                         /*
2726                          * Need to drop our head ref lock and re-acquire the
2727                          * delayed ref lock and then re-check to make sure
2728                          * nobody got added.
2729                          */
2730                         spin_unlock(&locked_ref->lock);
2731                         spin_lock(&delayed_refs->lock);
2732                         spin_lock(&locked_ref->lock);
2733                         if (!list_empty(&locked_ref->ref_list) ||
2734                             locked_ref->extent_op) {
2735                                 spin_unlock(&locked_ref->lock);
2736                                 spin_unlock(&delayed_refs->lock);
2737                                 continue;
2738                         }
2739                         ref->in_tree = 0;
2740                         delayed_refs->num_heads--;
2741                         rb_erase(&locked_ref->href_node,
2742                                  &delayed_refs->href_root);
2743                         spin_unlock(&delayed_refs->lock);
2744                 } else {
2745                         actual_count++;
2746                         ref->in_tree = 0;
2747                         list_del(&ref->list);
2748                         if (!list_empty(&ref->add_list))
2749                                 list_del(&ref->add_list);
2750                 }
2751                 atomic_dec(&delayed_refs->num_entries);
2752
2753                 if (!btrfs_delayed_ref_is_head(ref)) {
2754                         /*
2755                          * when we play the delayed ref, also correct the
2756                          * ref_mod on head
2757                          */
2758                         switch (ref->action) {
2759                         case BTRFS_ADD_DELAYED_REF:
2760                         case BTRFS_ADD_DELAYED_EXTENT:
2761                                 locked_ref->node.ref_mod -= ref->ref_mod;
2762                                 break;
2763                         case BTRFS_DROP_DELAYED_REF:
2764                                 locked_ref->node.ref_mod += ref->ref_mod;
2765                                 break;
2766                         default:
2767                                 WARN_ON(1);
2768                         }
2769                 }
2770                 spin_unlock(&locked_ref->lock);
2771
2772                 ret = run_one_delayed_ref(trans, fs_info, ref, extent_op,
2773                                           must_insert_reserved);
2774
2775                 btrfs_free_delayed_extent_op(extent_op);
2776                 if (ret) {
2777                         spin_lock(&delayed_refs->lock);
2778                         locked_ref->processing = 0;
2779                         delayed_refs->num_heads_ready++;
2780                         spin_unlock(&delayed_refs->lock);
2781                         btrfs_delayed_ref_unlock(locked_ref);
2782                         btrfs_put_delayed_ref(ref);
2783                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
2784                                     ret);
2785                         return ret;
2786                 }
2787
2788                 /*
2789                  * If this node is a head, that means all the refs in this head
2790                  * have been dealt with, and we will pick the next head to deal
2791                  * with, so we must unlock the head and drop it from the cluster
2792                  * list before we release it.
2793                  */
2794                 if (btrfs_delayed_ref_is_head(ref)) {
2795                         if (locked_ref->is_data &&
2796                             locked_ref->total_ref_mod < 0) {
2797                                 spin_lock(&delayed_refs->lock);
2798                                 delayed_refs->pending_csums -= ref->num_bytes;
2799                                 spin_unlock(&delayed_refs->lock);
2800                         }
2801                         btrfs_delayed_ref_unlock(locked_ref);
2802                         locked_ref = NULL;
2803                 }
2804                 btrfs_put_delayed_ref(ref);
2805                 count++;
2806                 cond_resched();
2807         }
2808
2809         /*
2810          * We don't want to include ref heads since we can have empty ref heads
2811          * and those will drastically skew our runtime down since we just do
2812          * accounting, no actual extent tree updates.
2813          */
2814         if (actual_count > 0) {
2815                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2816                 u64 avg;
2817
2818                 /*
2819                  * We weigh the current average higher than our current runtime
2820                  * to avoid large swings in the average.
2821                  */
2822                 spin_lock(&delayed_refs->lock);
2823                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2824                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2825                 spin_unlock(&delayed_refs->lock);
2826         }
2827         return 0;
2828 }
2829
2830 #ifdef SCRAMBLE_DELAYED_REFS
2831 /*
2832  * Normally delayed refs get processed in ascending bytenr order. This
2833  * correlates in most cases to the order added. To expose dependencies on this
2834  * order, we start to process the tree in the middle instead of the beginning
2835  */
2836 static u64 find_middle(struct rb_root *root)
2837 {
2838         struct rb_node *n = root->rb_node;
2839         struct btrfs_delayed_ref_node *entry;
2840         int alt = 1;
2841         u64 middle;
2842         u64 first = 0, last = 0;
2843
2844         n = rb_first(root);
2845         if (n) {
2846                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2847                 first = entry->bytenr;
2848         }
2849         n = rb_last(root);
2850         if (n) {
2851                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2852                 last = entry->bytenr;
2853         }
2854         n = root->rb_node;
2855
2856         while (n) {
2857                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2858                 WARN_ON(!entry->in_tree);
2859
2860                 middle = entry->bytenr;
2861
2862                 if (alt)
2863                         n = n->rb_left;
2864                 else
2865                         n = n->rb_right;
2866
2867                 alt = 1 - alt;
2868         }
2869         return middle;
2870 }
2871 #endif
2872
2873 static inline u64 heads_to_leaves(struct btrfs_fs_info *fs_info, u64 heads)
2874 {
2875         u64 num_bytes;
2876
2877         num_bytes = heads * (sizeof(struct btrfs_extent_item) +
2878                              sizeof(struct btrfs_extent_inline_ref));
2879         if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
2880                 num_bytes += heads * sizeof(struct btrfs_tree_block_info);
2881
2882         /*
2883          * We don't ever fill up leaves all the way so multiply by 2 just to be
2884          * closer to what we're really going to want to use.
2885          */
2886         return div_u64(num_bytes, BTRFS_LEAF_DATA_SIZE(fs_info));
2887 }
2888
2889 /*
2890  * Takes the number of bytes to be csumm'ed and figures out how many leaves it
2891  * would require to store the csums for that many bytes.
2892  */
2893 u64 btrfs_csum_bytes_to_leaves(struct btrfs_fs_info *fs_info, u64 csum_bytes)
2894 {
2895         u64 csum_size;
2896         u64 num_csums_per_leaf;
2897         u64 num_csums;
2898
2899         csum_size = BTRFS_MAX_ITEM_SIZE(fs_info);
2900         num_csums_per_leaf = div64_u64(csum_size,
2901                         (u64)btrfs_super_csum_size(fs_info->super_copy));
2902         num_csums = div64_u64(csum_bytes, fs_info->sectorsize);
2903         num_csums += num_csums_per_leaf - 1;
2904         num_csums = div64_u64(num_csums, num_csums_per_leaf);
2905         return num_csums;
2906 }
2907
2908 int btrfs_check_space_for_delayed_refs(struct btrfs_trans_handle *trans,
2909                                        struct btrfs_fs_info *fs_info)
2910 {
2911         struct btrfs_block_rsv *global_rsv;
2912         u64 num_heads = trans->transaction->delayed_refs.num_heads_ready;
2913         u64 csum_bytes = trans->transaction->delayed_refs.pending_csums;
2914         u64 num_dirty_bgs = trans->transaction->num_dirty_bgs;
2915         u64 num_bytes, num_dirty_bgs_bytes;
2916         int ret = 0;
2917
2918         num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
2919         num_heads = heads_to_leaves(fs_info, num_heads);
2920         if (num_heads > 1)
2921                 num_bytes += (num_heads - 1) * fs_info->nodesize;
2922         num_bytes <<= 1;
2923         num_bytes += btrfs_csum_bytes_to_leaves(fs_info, csum_bytes) *
2924                                                         fs_info->nodesize;
2925         num_dirty_bgs_bytes = btrfs_calc_trans_metadata_size(fs_info,
2926                                                              num_dirty_bgs);
2927         global_rsv = &fs_info->global_block_rsv;
2928
2929         /*
2930          * If we can't allocate any more chunks lets make sure we have _lots_ of
2931          * wiggle room since running delayed refs can create more delayed refs.
2932          */
2933         if (global_rsv->space_info->full) {
2934                 num_dirty_bgs_bytes <<= 1;
2935                 num_bytes <<= 1;
2936         }
2937
2938         spin_lock(&global_rsv->lock);
2939         if (global_rsv->reserved <= num_bytes + num_dirty_bgs_bytes)
2940                 ret = 1;
2941         spin_unlock(&global_rsv->lock);
2942         return ret;
2943 }
2944
2945 int btrfs_should_throttle_delayed_refs(struct btrfs_trans_handle *trans,
2946                                        struct btrfs_fs_info *fs_info)
2947 {
2948         u64 num_entries =
2949                 atomic_read(&trans->transaction->delayed_refs.num_entries);
2950         u64 avg_runtime;
2951         u64 val;
2952
2953         smp_mb();
2954         avg_runtime = fs_info->avg_delayed_ref_runtime;
2955         val = num_entries * avg_runtime;
2956         if (val >= NSEC_PER_SEC)
2957                 return 1;
2958         if (val >= NSEC_PER_SEC / 2)
2959                 return 2;
2960
2961         return btrfs_check_space_for_delayed_refs(trans, fs_info);
2962 }
2963
2964 struct async_delayed_refs {
2965         struct btrfs_root *root;
2966         u64 transid;
2967         int count;
2968         int error;
2969         int sync;
2970         struct completion wait;
2971         struct btrfs_work work;
2972 };
2973
2974 static inline struct async_delayed_refs *
2975 to_async_delayed_refs(struct btrfs_work *work)
2976 {
2977         return container_of(work, struct async_delayed_refs, work);
2978 }
2979
2980 static void delayed_ref_async_start(struct btrfs_work *work)
2981 {
2982         struct async_delayed_refs *async = to_async_delayed_refs(work);
2983         struct btrfs_trans_handle *trans;
2984         struct btrfs_fs_info *fs_info = async->root->fs_info;
2985         int ret;
2986
2987         /* if the commit is already started, we don't need to wait here */
2988         if (btrfs_transaction_blocked(fs_info))
2989                 goto done;
2990
2991         trans = btrfs_join_transaction(async->root);
2992         if (IS_ERR(trans)) {
2993                 async->error = PTR_ERR(trans);
2994                 goto done;
2995         }
2996
2997         /*
2998          * trans->sync means that when we call end_transaction, we won't
2999          * wait on delayed refs
3000          */
3001         trans->sync = true;
3002
3003         /* Don't bother flushing if we got into a different transaction */
3004         if (trans->transid > async->transid)
3005                 goto end;
3006
3007         ret = btrfs_run_delayed_refs(trans, fs_info, async->count);
3008         if (ret)
3009                 async->error = ret;
3010 end:
3011         ret = btrfs_end_transaction(trans);
3012         if (ret && !async->error)
3013                 async->error = ret;
3014 done:
3015         if (async->sync)
3016                 complete(&async->wait);
3017         else
3018                 kfree(async);
3019 }
3020
3021 int btrfs_async_run_delayed_refs(struct btrfs_fs_info *fs_info,
3022                                  unsigned long count, u64 transid, int wait)
3023 {
3024         struct async_delayed_refs *async;
3025         int ret;
3026
3027         async = kmalloc(sizeof(*async), GFP_NOFS);
3028         if (!async)
3029                 return -ENOMEM;
3030
3031         async->root = fs_info->tree_root;
3032         async->count = count;
3033         async->error = 0;
3034         async->transid = transid;
3035         if (wait)
3036                 async->sync = 1;
3037         else
3038                 async->sync = 0;
3039         init_completion(&async->wait);
3040
3041         btrfs_init_work(&async->work, btrfs_extent_refs_helper,
3042                         delayed_ref_async_start, NULL, NULL);
3043
3044         btrfs_queue_work(fs_info->extent_workers, &async->work);
3045
3046         if (wait) {
3047                 wait_for_completion(&async->wait);
3048                 ret = async->error;
3049                 kfree(async);
3050                 return ret;
3051         }
3052         return 0;
3053 }
3054
3055 /*
3056  * this starts processing the delayed reference count updates and
3057  * extent insertions we have queued up so far.  count can be
3058  * 0, which means to process everything in the tree at the start
3059  * of the run (but not newly added entries), or it can be some target
3060  * number you'd like to process.
3061  *
3062  * Returns 0 on success or if called with an aborted transaction
3063  * Returns <0 on error and aborts the transaction
3064  */
3065 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
3066                            struct btrfs_fs_info *fs_info, unsigned long count)
3067 {
3068         struct rb_node *node;
3069         struct btrfs_delayed_ref_root *delayed_refs;
3070         struct btrfs_delayed_ref_head *head;
3071         int ret;
3072         int run_all = count == (unsigned long)-1;
3073         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
3074
3075         /* We'll clean this up in btrfs_cleanup_transaction */
3076         if (trans->aborted)
3077                 return 0;
3078
3079         if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
3080                 return 0;
3081
3082         delayed_refs = &trans->transaction->delayed_refs;
3083         if (count == 0)
3084                 count = atomic_read(&delayed_refs->num_entries) * 2;
3085
3086 again:
3087 #ifdef SCRAMBLE_DELAYED_REFS
3088         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
3089 #endif
3090         trans->can_flush_pending_bgs = false;
3091         ret = __btrfs_run_delayed_refs(trans, fs_info, count);
3092         if (ret < 0) {
3093                 btrfs_abort_transaction(trans, ret);
3094                 return ret;
3095         }
3096
3097         if (run_all) {
3098                 if (!list_empty(&trans->new_bgs))
3099                         btrfs_create_pending_block_groups(trans, fs_info);
3100
3101                 spin_lock(&delayed_refs->lock);
3102                 node = rb_first(&delayed_refs->href_root);
3103                 if (!node) {
3104                         spin_unlock(&delayed_refs->lock);
3105                         goto out;
3106                 }
3107
3108                 while (node) {
3109                         head = rb_entry(node, struct btrfs_delayed_ref_head,
3110                                         href_node);
3111                         if (btrfs_delayed_ref_is_head(&head->node)) {
3112                                 struct btrfs_delayed_ref_node *ref;
3113
3114                                 ref = &head->node;
3115                                 refcount_inc(&ref->refs);
3116
3117                                 spin_unlock(&delayed_refs->lock);
3118                                 /*
3119                                  * Mutex was contended, block until it's
3120                                  * released and try again
3121                                  */
3122                                 mutex_lock(&head->mutex);
3123                                 mutex_unlock(&head->mutex);
3124
3125                                 btrfs_put_delayed_ref(ref);
3126                                 cond_resched();
3127                                 goto again;
3128                         } else {
3129                                 WARN_ON(1);
3130                         }
3131                         node = rb_next(node);
3132                 }
3133                 spin_unlock(&delayed_refs->lock);
3134                 cond_resched();
3135                 goto again;
3136         }
3137 out:
3138         trans->can_flush_pending_bgs = can_flush_pending_bgs;
3139         return 0;
3140 }
3141
3142 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
3143                                 struct btrfs_fs_info *fs_info,
3144                                 u64 bytenr, u64 num_bytes, u64 flags,
3145                                 int level, int is_data)
3146 {
3147         struct btrfs_delayed_extent_op *extent_op;
3148         int ret;
3149
3150         extent_op = btrfs_alloc_delayed_extent_op();
3151         if (!extent_op)
3152                 return -ENOMEM;
3153
3154         extent_op->flags_to_set = flags;
3155         extent_op->update_flags = true;
3156         extent_op->update_key = false;
3157         extent_op->is_data = is_data ? true : false;
3158         extent_op->level = level;
3159
3160         ret = btrfs_add_delayed_extent_op(fs_info, trans, bytenr,
3161                                           num_bytes, extent_op);
3162         if (ret)
3163                 btrfs_free_delayed_extent_op(extent_op);
3164         return ret;
3165 }
3166
3167 static noinline int check_delayed_ref(struct btrfs_root *root,
3168                                       struct btrfs_path *path,
3169                                       u64 objectid, u64 offset, u64 bytenr)
3170 {
3171         struct btrfs_delayed_ref_head *head;
3172         struct btrfs_delayed_ref_node *ref;
3173         struct btrfs_delayed_data_ref *data_ref;
3174         struct btrfs_delayed_ref_root *delayed_refs;
3175         struct btrfs_transaction *cur_trans;
3176         int ret = 0;
3177
3178         spin_lock(&root->fs_info->trans_lock);
3179         cur_trans = root->fs_info->running_transaction;
3180         if (cur_trans)
3181                 refcount_inc(&cur_trans->use_count);
3182         spin_unlock(&root->fs_info->trans_lock);
3183         if (!cur_trans)
3184                 return 0;
3185
3186         delayed_refs = &cur_trans->delayed_refs;
3187         spin_lock(&delayed_refs->lock);
3188         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3189         if (!head) {
3190                 spin_unlock(&delayed_refs->lock);
3191                 btrfs_put_transaction(cur_trans);
3192                 return 0;
3193         }
3194
3195         if (!mutex_trylock(&head->mutex)) {
3196                 refcount_inc(&head->node.refs);
3197                 spin_unlock(&delayed_refs->lock);
3198
3199                 btrfs_release_path(path);
3200
3201                 /*
3202                  * Mutex was contended, block until it's released and let
3203                  * caller try again
3204                  */
3205                 mutex_lock(&head->mutex);
3206                 mutex_unlock(&head->mutex);
3207                 btrfs_put_delayed_ref(&head->node);
3208                 btrfs_put_transaction(cur_trans);
3209                 return -EAGAIN;
3210         }
3211         spin_unlock(&delayed_refs->lock);
3212
3213         spin_lock(&head->lock);
3214         list_for_each_entry(ref, &head->ref_list, list) {
3215                 /* If it's a shared ref we know a cross reference exists */
3216                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
3217                         ret = 1;
3218                         break;
3219                 }
3220
3221                 data_ref = btrfs_delayed_node_to_data_ref(ref);
3222
3223                 /*
3224                  * If our ref doesn't match the one we're currently looking at
3225                  * then we have a cross reference.
3226                  */
3227                 if (data_ref->root != root->root_key.objectid ||
3228                     data_ref->objectid != objectid ||
3229                     data_ref->offset != offset) {
3230                         ret = 1;
3231                         break;
3232                 }
3233         }
3234         spin_unlock(&head->lock);
3235         mutex_unlock(&head->mutex);
3236         btrfs_put_transaction(cur_trans);
3237         return ret;
3238 }
3239
3240 static noinline int check_committed_ref(struct btrfs_root *root,
3241                                         struct btrfs_path *path,
3242                                         u64 objectid, u64 offset, u64 bytenr)
3243 {
3244         struct btrfs_fs_info *fs_info = root->fs_info;
3245         struct btrfs_root *extent_root = fs_info->extent_root;
3246         struct extent_buffer *leaf;
3247         struct btrfs_extent_data_ref *ref;
3248         struct btrfs_extent_inline_ref *iref;
3249         struct btrfs_extent_item *ei;
3250         struct btrfs_key key;
3251         u32 item_size;
3252         int type;
3253         int ret;
3254
3255         key.objectid = bytenr;
3256         key.offset = (u64)-1;
3257         key.type = BTRFS_EXTENT_ITEM_KEY;
3258
3259         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
3260         if (ret < 0)
3261                 goto out;
3262         BUG_ON(ret == 0); /* Corruption */
3263
3264         ret = -ENOENT;
3265         if (path->slots[0] == 0)
3266                 goto out;
3267
3268         path->slots[0]--;
3269         leaf = path->nodes[0];
3270         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3271
3272         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
3273                 goto out;
3274
3275         ret = 1;
3276         item_size = btrfs_item_size_nr(leaf, path->slots[0]);
3277 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3278         if (item_size < sizeof(*ei)) {
3279                 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3280                 goto out;
3281         }
3282 #endif
3283         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
3284
3285         if (item_size != sizeof(*ei) +
3286             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
3287                 goto out;
3288
3289         if (btrfs_extent_generation(leaf, ei) <=
3290             btrfs_root_last_snapshot(&root->root_item))
3291                 goto out;
3292
3293         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
3294
3295         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
3296         if (type != BTRFS_EXTENT_DATA_REF_KEY)
3297                 goto out;
3298
3299         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
3300         if (btrfs_extent_refs(leaf, ei) !=
3301             btrfs_extent_data_ref_count(leaf, ref) ||
3302             btrfs_extent_data_ref_root(leaf, ref) !=
3303             root->root_key.objectid ||
3304             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
3305             btrfs_extent_data_ref_offset(leaf, ref) != offset)
3306                 goto out;
3307
3308         ret = 0;
3309 out:
3310         return ret;
3311 }
3312
3313 int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
3314                           u64 bytenr)
3315 {
3316         struct btrfs_path *path;
3317         int ret;
3318         int ret2;
3319
3320         path = btrfs_alloc_path();
3321         if (!path)
3322                 return -ENOENT;
3323
3324         do {
3325                 ret = check_committed_ref(root, path, objectid,
3326                                           offset, bytenr);
3327                 if (ret && ret != -ENOENT)
3328                         goto out;
3329
3330                 ret2 = check_delayed_ref(root, path, objectid,
3331                                          offset, bytenr);
3332         } while (ret2 == -EAGAIN);
3333
3334         if (ret2 && ret2 != -ENOENT) {
3335                 ret = ret2;
3336                 goto out;
3337         }
3338
3339         if (ret != -ENOENT || ret2 != -ENOENT)
3340                 ret = 0;
3341 out:
3342         btrfs_free_path(path);
3343         if (root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID)
3344                 WARN_ON(ret > 0);
3345         return ret;
3346 }
3347
3348 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
3349                            struct btrfs_root *root,
3350                            struct extent_buffer *buf,
3351                            int full_backref, int inc)
3352 {
3353         struct btrfs_fs_info *fs_info = root->fs_info;
3354         u64 bytenr;
3355         u64 num_bytes;
3356         u64 parent;
3357         u64 ref_root;
3358         u32 nritems;
3359         struct btrfs_key key;
3360         struct btrfs_file_extent_item *fi;
3361         int i;
3362         int level;
3363         int ret = 0;
3364         int (*process_func)(struct btrfs_trans_handle *,
3365                             struct btrfs_fs_info *,
3366                             u64, u64, u64, u64, u64, u64);
3367
3368
3369         if (btrfs_is_testing(fs_info))
3370                 return 0;
3371
3372         ref_root = btrfs_header_owner(buf);
3373         nritems = btrfs_header_nritems(buf);
3374         level = btrfs_header_level(buf);
3375
3376         if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state) && level == 0)
3377                 return 0;
3378
3379         if (inc)
3380                 process_func = btrfs_inc_extent_ref;
3381         else
3382                 process_func = btrfs_free_extent;
3383
3384         if (full_backref)
3385                 parent = buf->start;
3386         else
3387                 parent = 0;
3388
3389         for (i = 0; i < nritems; i++) {
3390                 if (level == 0) {
3391                         btrfs_item_key_to_cpu(buf, &key, i);
3392                         if (key.type != BTRFS_EXTENT_DATA_KEY)
3393                                 continue;
3394                         fi = btrfs_item_ptr(buf, i,
3395                                             struct btrfs_file_extent_item);
3396                         if (btrfs_file_extent_type(buf, fi) ==
3397                             BTRFS_FILE_EXTENT_INLINE)
3398                                 continue;
3399                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
3400                         if (bytenr == 0)
3401                                 continue;
3402
3403                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
3404                         key.offset -= btrfs_file_extent_offset(buf, fi);
3405                         ret = process_func(trans, fs_info, bytenr, num_bytes,
3406                                            parent, ref_root, key.objectid,
3407                                            key.offset);
3408                         if (ret)
3409                                 goto fail;
3410                 } else {
3411                         bytenr = btrfs_node_blockptr(buf, i);
3412                         num_bytes = fs_info->nodesize;
3413                         ret = process_func(trans, fs_info, bytenr, num_bytes,
3414                                            parent, ref_root, level - 1, 0);
3415                         if (ret)
3416                                 goto fail;
3417                 }
3418         }
3419         return 0;
3420 fail:
3421         return ret;
3422 }
3423
3424 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3425                   struct extent_buffer *buf, int full_backref)
3426 {
3427         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
3428 }
3429
3430 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
3431                   struct extent_buffer *buf, int full_backref)
3432 {
3433         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
3434 }
3435
3436 static int write_one_cache_group(struct btrfs_trans_handle *trans,
3437                                  struct btrfs_fs_info *fs_info,
3438                                  struct btrfs_path *path,
3439                                  struct btrfs_block_group_cache *cache)
3440 {
3441         int ret;
3442         struct btrfs_root *extent_root = fs_info->extent_root;
3443         unsigned long bi;
3444         struct extent_buffer *leaf;
3445
3446         ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
3447         if (ret) {
3448                 if (ret > 0)
3449                         ret = -ENOENT;
3450                 goto fail;
3451         }
3452
3453         leaf = path->nodes[0];
3454         bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
3455         write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
3456         btrfs_mark_buffer_dirty(leaf);
3457 fail:
3458         btrfs_release_path(path);
3459         return ret;
3460
3461 }
3462
3463 static struct btrfs_block_group_cache *
3464 next_block_group(struct btrfs_fs_info *fs_info,
3465                  struct btrfs_block_group_cache *cache)
3466 {
3467         struct rb_node *node;
3468
3469         spin_lock(&fs_info->block_group_cache_lock);
3470
3471         /* If our block group was removed, we need a full search. */
3472         if (RB_EMPTY_NODE(&cache->cache_node)) {
3473                 const u64 next_bytenr = cache->key.objectid + cache->key.offset;
3474
3475                 spin_unlock(&fs_info->block_group_cache_lock);
3476                 btrfs_put_block_group(cache);
3477                 cache = btrfs_lookup_first_block_group(fs_info, next_bytenr); return cache;
3478         }
3479         node = rb_next(&cache->cache_node);
3480         btrfs_put_block_group(cache);
3481         if (node) {
3482                 cache = rb_entry(node, struct btrfs_block_group_cache,
3483                                  cache_node);
3484                 btrfs_get_block_group(cache);
3485         } else
3486                 cache = NULL;
3487         spin_unlock(&fs_info->block_group_cache_lock);
3488         return cache;
3489 }
3490
3491 static int cache_save_setup(struct btrfs_block_group_cache *block_group,
3492                             struct btrfs_trans_handle *trans,
3493                             struct btrfs_path *path)
3494 {
3495         struct btrfs_fs_info *fs_info = block_group->fs_info;
3496         struct btrfs_root *root = fs_info->tree_root;
3497         struct inode *inode = NULL;
3498         struct extent_changeset *data_reserved = NULL;
3499         u64 alloc_hint = 0;
3500         int dcs = BTRFS_DC_ERROR;
3501         u64 num_pages = 0;
3502         int retries = 0;
3503         int ret = 0;
3504
3505         /*
3506          * If this block group is smaller than 100 megs don't bother caching the
3507          * block group.
3508          */
3509         if (block_group->key.offset < (100 * SZ_1M)) {
3510                 spin_lock(&block_group->lock);
3511                 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
3512                 spin_unlock(&block_group->lock);
3513                 return 0;
3514         }
3515
3516         if (trans->aborted)
3517                 return 0;
3518 again:
3519         inode = lookup_free_space_inode(fs_info, block_group, path);
3520         if (IS_ERR(inode) && PTR_ERR(inode) != -ENOENT) {
3521                 ret = PTR_ERR(inode);
3522                 btrfs_release_path(path);
3523                 goto out;
3524         }
3525
3526         if (IS_ERR(inode)) {
3527                 BUG_ON(retries);
3528                 retries++;
3529
3530                 if (block_group->ro)
3531                         goto out_free;
3532
3533                 ret = create_free_space_inode(fs_info, trans, block_group,
3534                                               path);
3535                 if (ret)
3536                         goto out_free;
3537                 goto again;
3538         }
3539
3540         /*
3541          * We want to set the generation to 0, that way if anything goes wrong
3542          * from here on out we know not to trust this cache when we load up next
3543          * time.
3544          */
3545         BTRFS_I(inode)->generation = 0;
3546         ret = btrfs_update_inode(trans, root, inode);
3547         if (ret) {
3548                 /*
3549                  * So theoretically we could recover from this, simply set the
3550                  * super cache generation to 0 so we know to invalidate the
3551                  * cache, but then we'd have to keep track of the block groups
3552                  * that fail this way so we know we _have_ to reset this cache
3553                  * before the next commit or risk reading stale cache.  So to
3554                  * limit our exposure to horrible edge cases lets just abort the
3555                  * transaction, this only happens in really bad situations
3556                  * anyway.
3557                  */
3558                 btrfs_abort_transaction(trans, ret);
3559                 goto out_put;
3560         }
3561         WARN_ON(ret);
3562
3563         /* We've already setup this transaction, go ahead and exit */
3564         if (block_group->cache_generation == trans->transid &&
3565             i_size_read(inode)) {
3566                 dcs = BTRFS_DC_SETUP;
3567                 goto out_put;
3568         }
3569
3570         if (i_size_read(inode) > 0) {
3571                 ret = btrfs_check_trunc_cache_free_space(fs_info,
3572                                         &fs_info->global_block_rsv);
3573                 if (ret)
3574                         goto out_put;
3575
3576                 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
3577                 if (ret)
3578                         goto out_put;
3579         }
3580
3581         spin_lock(&block_group->lock);
3582         if (block_group->cached != BTRFS_CACHE_FINISHED ||
3583             !btrfs_test_opt(fs_info, SPACE_CACHE)) {
3584                 /*
3585                  * don't bother trying to write stuff out _if_
3586                  * a) we're not cached,
3587                  * b) we're with nospace_cache mount option,
3588                  * c) we're with v2 space_cache (FREE_SPACE_TREE).
3589                  */
3590                 dcs = BTRFS_DC_WRITTEN;
3591                 spin_unlock(&block_group->lock);
3592                 goto out_put;
3593         }
3594         spin_unlock(&block_group->lock);
3595
3596         /*
3597          * We hit an ENOSPC when setting up the cache in this transaction, just
3598          * skip doing the setup, we've already cleared the cache so we're safe.
3599          */
3600         if (test_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags)) {
3601                 ret = -ENOSPC;
3602                 goto out_put;
3603         }
3604
3605         /*
3606          * Try to preallocate enough space based on how big the block group is.
3607          * Keep in mind this has to include any pinned space which could end up
3608          * taking up quite a bit since it's not folded into the other space
3609          * cache.
3610          */
3611         num_pages = div_u64(block_group->key.offset, SZ_256M);
3612         if (!num_pages)
3613                 num_pages = 1;
3614
3615         num_pages *= 16;
3616         num_pages *= PAGE_SIZE;
3617
3618         ret = btrfs_check_data_free_space(inode, &data_reserved, 0, num_pages);
3619         if (ret)
3620                 goto out_put;
3621
3622         ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, num_pages,
3623                                               num_pages, num_pages,
3624                                               &alloc_hint);
3625         /*
3626          * Our cache requires contiguous chunks so that we don't modify a bunch
3627          * of metadata or split extents when writing the cache out, which means
3628          * we can enospc if we are heavily fragmented in addition to just normal
3629          * out of space conditions.  So if we hit this just skip setting up any
3630          * other block groups for this transaction, maybe we'll unpin enough
3631          * space the next time around.
3632          */
3633         if (!ret)
3634                 dcs = BTRFS_DC_SETUP;
3635         else if (ret == -ENOSPC)
3636                 set_bit(BTRFS_TRANS_CACHE_ENOSPC, &trans->transaction->flags);
3637
3638 out_put:
3639         iput(inode);
3640 out_free:
3641         btrfs_release_path(path);
3642 out:
3643         spin_lock(&block_group->lock);
3644         if (!ret && dcs == BTRFS_DC_SETUP)
3645                 block_group->cache_generation = trans->transid;
3646         block_group->disk_cache_state = dcs;
3647         spin_unlock(&block_group->lock);
3648
3649         extent_changeset_free(data_reserved);
3650         return ret;
3651 }
3652
3653 int btrfs_setup_space_cache(struct btrfs_trans_handle *trans,
3654                             struct btrfs_fs_info *fs_info)
3655 {
3656         struct btrfs_block_group_cache *cache, *tmp;
3657         struct btrfs_transaction *cur_trans = trans->transaction;
3658         struct btrfs_path *path;
3659
3660         if (list_empty(&cur_trans->dirty_bgs) ||
3661             !btrfs_test_opt(fs_info, SPACE_CACHE))
3662                 return 0;
3663
3664         path = btrfs_alloc_path();
3665         if (!path)
3666                 return -ENOMEM;
3667
3668         /* Could add new block groups, use _safe just in case */
3669         list_for_each_entry_safe(cache, tmp, &cur_trans->dirty_bgs,
3670                                  dirty_list) {
3671                 if (cache->disk_cache_state == BTRFS_DC_CLEAR)
3672                         cache_save_setup(cache, trans, path);
3673         }
3674
3675         btrfs_free_path(path);
3676         return 0;
3677 }
3678
3679 /*
3680  * transaction commit does final block group cache writeback during a
3681  * critical section where nothing is allowed to change the FS.  This is
3682  * required in order for the cache to actually match the block group,
3683  * but can introduce a lot of latency into the commit.
3684  *
3685  * So, btrfs_start_dirty_block_groups is here to kick off block group
3686  * cache IO.  There's a chance we'll have to redo some of it if the
3687  * block group changes again during the commit, but it greatly reduces
3688  * the commit latency by getting rid of the easy block groups while
3689  * we're still allowing others to join the commit.
3690  */
3691 int btrfs_start_dirty_block_groups(struct btrfs_trans_handle *trans,
3692                                    struct btrfs_fs_info *fs_info)
3693 {
3694         struct btrfs_block_group_cache *cache;
3695         struct btrfs_transaction *cur_trans = trans->transaction;
3696         int ret = 0;
3697         int should_put;
3698         struct btrfs_path *path = NULL;
3699         LIST_HEAD(dirty);
3700         struct list_head *io = &cur_trans->io_bgs;
3701         int num_started = 0;
3702         int loops = 0;
3703
3704         spin_lock(&cur_trans->dirty_bgs_lock);
3705         if (list_empty(&cur_trans->dirty_bgs)) {
3706                 spin_unlock(&cur_trans->dirty_bgs_lock);
3707                 return 0;
3708         }
3709         list_splice_init(&cur_trans->dirty_bgs, &dirty);
3710         spin_unlock(&cur_trans->dirty_bgs_lock);
3711
3712 again:
3713         /*
3714          * make sure all the block groups on our dirty list actually
3715          * exist
3716          */
3717         btrfs_create_pending_block_groups(trans, fs_info);
3718
3719         if (!path) {
3720                 path = btrfs_alloc_path();
3721                 if (!path)
3722                         return -ENOMEM;
3723         }
3724
3725         /*
3726          * cache_write_mutex is here only to save us from balance or automatic
3727          * removal of empty block groups deleting this block group while we are
3728          * writing out the cache
3729          */
3730         mutex_lock(&trans->transaction->cache_write_mutex);
3731         while (!list_empty(&dirty)) {
3732                 cache = list_first_entry(&dirty,
3733                                          struct btrfs_block_group_cache,
3734                                          dirty_list);
3735                 /*
3736                  * this can happen if something re-dirties a block
3737                  * group that is already under IO.  Just wait for it to
3738                  * finish and then do it all again
3739                  */
3740                 if (!list_empty(&cache->io_list)) {
3741                         list_del_init(&cache->io_list);
3742                         btrfs_wait_cache_io(trans, cache, path);
3743                         btrfs_put_block_group(cache);
3744                 }
3745
3746
3747                 /*
3748                  * btrfs_wait_cache_io uses the cache->dirty_list to decide
3749                  * if it should update the cache_state.  Don't delete
3750                  * until after we wait.
3751                  *
3752                  * Since we're not running in the commit critical section
3753                  * we need the dirty_bgs_lock to protect from update_block_group
3754                  */
3755                 spin_lock(&cur_trans->dirty_bgs_lock);
3756                 list_del_init(&cache->dirty_list);
3757                 spin_unlock(&cur_trans->dirty_bgs_lock);
3758
3759                 should_put = 1;
3760
3761                 cache_save_setup(cache, trans, path);
3762
3763                 if (cache->disk_cache_state == BTRFS_DC_SETUP) {
3764                         cache->io_ctl.inode = NULL;
3765                         ret = btrfs_write_out_cache(fs_info, trans,
3766                                                     cache, path);
3767                         if (ret == 0 && cache->io_ctl.inode) {
3768                                 num_started++;
3769                                 should_put = 0;
3770
3771                                 /*
3772                                  * the cache_write_mutex is protecting
3773                                  * the io_list
3774                                  */
3775                                 list_add_tail(&cache->io_list, io);
3776                         } else {
3777                                 /*
3778                                  * if we failed to write the cache, the
3779                                  * generation will be bad and life goes on
3780                                  */
3781                                 ret = 0;
3782                         }
3783                 }
3784                 if (!ret) {
3785                         ret = write_one_cache_group(trans, fs_info,
3786                                                     path, cache);
3787                         /*
3788                          * Our block group might still be attached to the list
3789                          * of new block groups in the transaction handle of some
3790                          * other task (struct btrfs_trans_handle->new_bgs). This
3791                          * means its block group item isn't yet in the extent
3792                          * tree. If this happens ignore the error, as we will
3793                          * try again later in the critical section of the
3794                          * transaction commit.
3795                          */
3796                         if (ret == -ENOENT) {
3797                                 ret = 0;
3798                                 spin_lock(&cur_trans->dirty_bgs_lock);
3799                                 if (list_empty(&cache->dirty_list)) {
3800                                         list_add_tail(&cache->dirty_list,
3801                                                       &cur_trans->dirty_bgs);
3802                                         btrfs_get_block_group(cache);
3803                                 }
3804                                 spin_unlock(&cur_trans->dirty_bgs_lock);
3805                         } else if (ret) {
3806                                 btrfs_abort_transaction(trans, ret);
3807                         }
3808                 }
3809
3810                 /* if its not on the io list, we need to put the block group */
3811                 if (should_put)
3812                         btrfs_put_block_group(cache);
3813
3814                 if (ret)
3815                         break;
3816
3817                 /*
3818                  * Avoid blocking other tasks for too long. It might even save
3819                  * us from writing caches for block groups that are going to be
3820                  * removed.
3821                  */
3822                 mutex_unlock(&trans->transaction->cache_write_mutex);
3823                 mutex_lock(&trans->transaction->cache_write_mutex);
3824         }
3825         mutex_unlock(&trans->transaction->cache_write_mutex);
3826
3827         /*
3828          * go through delayed refs for all the stuff we've just kicked off
3829          * and then loop back (just once)
3830          */
3831         ret = btrfs_run_delayed_refs(trans, fs_info, 0);
3832         if (!ret && loops == 0) {
3833                 loops++;
3834                 spin_lock(&cur_trans->dirty_bgs_lock);
3835                 list_splice_init(&cur_trans->dirty_bgs, &dirty);
3836                 /*
3837                  * dirty_bgs_lock protects us from concurrent block group
3838                  * deletes too (not just cache_write_mutex).
3839                  */
3840                 if (!list_empty(&dirty)) {
3841                         spin_unlock(&cur_trans->dirty_bgs_lock);
3842                         goto again;
3843                 }
3844                 spin_unlock(&cur_trans->dirty_bgs_lock);
3845         } else if (ret < 0) {
3846                 btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
3847         }
3848
3849         btrfs_free_path(path);
3850         return ret;
3851 }
3852
3853 int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
3854                                    struct btrfs_fs_info *fs_info)
3855 {
3856         struct btrfs_block_group_cache *cache;
3857         struct btrfs_transaction *cur_trans = trans->transaction;
3858         int ret = 0;
3859         int should_put;
3860         struct btrfs_path *path;
3861         struct list_head *io = &cur_trans->io_bgs;
3862         int num_started = 0;
3863
3864         path = btrfs_alloc_path();
3865         if (!path)
3866                 return -ENOMEM;
3867
3868         /*
3869          * Even though we are in the critical section of the transaction commit,
3870          * we can still have concurrent tasks adding elements to this
3871          * transaction's list of dirty block groups. These tasks correspond to
3872          * endio free space workers started when writeback finishes for a
3873          * space cache, which run inode.c:btrfs_finish_ordered_io(), and can
3874          * allocate new block groups as a result of COWing nodes of the root
3875          * tree when updating the free space inode. The writeback for the space
3876          * caches is triggered by an earlier call to
3877          * btrfs_start_dirty_block_groups() and iterations of the following
3878          * loop.
3879          * Also we want to do the cache_save_setup first and then run the
3880          * delayed refs to make sure we have the best chance at doing this all
3881          * in one shot.
3882          */
3883         spin_lock(&cur_trans->dirty_bgs_lock);
3884         while (!list_empty(&cur_trans->dirty_bgs)) {
3885                 cache = list_first_entry(&cur_trans->dirty_bgs,
3886                                          struct btrfs_block_group_cache,
3887                                          dirty_list);
3888
3889                 /*
3890                  * this can happen if cache_save_setup re-dirties a block
3891                  * group that is already under IO.  Just wait for it to
3892                  * finish and then do it all again
3893                  */
3894                 if (!list_empty(&cache->io_list)) {
3895                         spin_unlock(&cur_trans->dirty_bgs_lock);
3896                         list_del_init(&cache->io_list);
3897                         btrfs_wait_cache_io(trans, cache, path);
3898                         btrfs_put_block_group(cache);
3899                         spin_lock(&cur_trans->dirty_bgs_lock);
3900                 }
3901
3902                 /*
3903                  * don't remove from the dirty list until after we've waited
3904                  * on any pending IO
3905                  */
3906                 list_del_init(&cache->dirty_list);
3907                 spin_unlock(&cur_trans->dirty_bgs_lock);
3908                 should_put = 1;
3909
3910                 cache_save_setup(cache, trans, path);
3911
3912                 if (!ret)
3913                         ret = btrfs_run_delayed_refs(trans, fs_info,
3914                                                      (unsigned long) -1);
3915
3916                 if (!ret && cache->disk_cache_state == BTRFS_DC_SETUP) {
3917                         cache->io_ctl.inode = NULL;
3918                         ret = btrfs_write_out_cache(fs_info, trans,
3919                                                     cache, path);
3920                         if (ret == 0 && cache->io_ctl.inode) {
3921                                 num_started++;
3922                                 should_put = 0;
3923                                 list_add_tail(&cache->io_list, io);
3924                         } else {
3925                                 /*
3926                                  * if we failed to write the cache, the
3927                                  * generation will be bad and life goes on
3928                                  */
3929                                 ret = 0;
3930                         }
3931                 }
3932                 if (!ret) {
3933                         ret = write_one_cache_group(trans, fs_info,
3934                                                     path, cache);
3935                         /*
3936                          * One of the free space endio workers might have
3937                          * created a new block group while updating a free space
3938                          * cache's inode (at inode.c:btrfs_finish_ordered_io())
3939                          * and hasn't released its transaction handle yet, in
3940                          * which case the new block group is still attached to
3941                          * its transaction handle and its creation has not
3942                          * finished yet (no block group item in the extent tree
3943                          * yet, etc). If this is the case, wait for all free
3944                          * space endio workers to finish and retry. This is a
3945                          * a very rare case so no need for a more efficient and
3946                          * complex approach.
3947                          */
3948                         if (ret == -ENOENT) {
3949                                 wait_event(cur_trans->writer_wait,
3950                                    atomic_read(&cur_trans->num_writers) == 1);
3951                                 ret = write_one_cache_group(trans, fs_info,
3952                                                             path, cache);
3953                         }
3954                         if (ret)
3955                                 btrfs_abort_transaction(trans, ret);
3956                 }
3957
3958                 /* if its not on the io list, we need to put the block group */
3959                 if (should_put)
3960                         btrfs_put_block_group(cache);
3961                 spin_lock(&cur_trans->dirty_bgs_lock);
3962         }
3963         spin_unlock(&cur_trans->dirty_bgs_lock);
3964
3965         while (!list_empty(io)) {
3966                 cache = list_first_entry(io, struct btrfs_block_group_cache,
3967                                          io_list);
3968                 list_del_init(&cache->io_list);
3969                 btrfs_wait_cache_io(trans, cache, path);
3970                 btrfs_put_block_group(cache);
3971         }
3972
3973         btrfs_free_path(path);
3974         return ret;
3975 }
3976
3977 int btrfs_extent_readonly(struct btrfs_fs_info *fs_info, u64 bytenr)
3978 {
3979         struct btrfs_block_group_cache *block_group;
3980         int readonly = 0;
3981
3982         block_group = btrfs_lookup_block_group(fs_info, bytenr);
3983         if (!block_group || block_group->ro)
3984                 readonly = 1;
3985         if (block_group)
3986                 btrfs_put_block_group(block_group);
3987         return readonly;
3988 }
3989
3990 bool btrfs_inc_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
3991 {
3992         struct btrfs_block_group_cache *bg;
3993         bool ret = true;
3994
3995         bg = btrfs_lookup_block_group(fs_info, bytenr);
3996         if (!bg)
3997                 return false;
3998
3999         spin_lock(&bg->lock);
4000         if (bg->ro)
4001                 ret = false;
4002         else
4003                 atomic_inc(&bg->nocow_writers);
4004         spin_unlock(&bg->lock);
4005
4006         /* no put on block group, done by btrfs_dec_nocow_writers */
4007         if (!ret)
4008                 btrfs_put_block_group(bg);
4009
4010         return ret;
4011
4012 }
4013
4014 void btrfs_dec_nocow_writers(struct btrfs_fs_info *fs_info, u64 bytenr)
4015 {
4016         struct btrfs_block_group_cache *bg;
4017
4018         bg = btrfs_lookup_block_group(fs_info, bytenr);
4019         ASSERT(bg);
4020         if (atomic_dec_and_test(&bg->nocow_writers))
4021                 wake_up_atomic_t(&bg->nocow_writers);
4022         /*
4023          * Once for our lookup and once for the lookup done by a previous call
4024          * to btrfs_inc_nocow_writers()
4025          */
4026         btrfs_put_block_group(bg);
4027         btrfs_put_block_group(bg);
4028 }
4029
4030 static int btrfs_wait_nocow_writers_atomic_t(atomic_t *a)
4031 {
4032         schedule();
4033         return 0;
4034 }
4035
4036 void btrfs_wait_nocow_writers(struct btrfs_block_group_cache *bg)
4037 {
4038         wait_on_atomic_t(&bg->nocow_writers,
4039                          btrfs_wait_nocow_writers_atomic_t,
4040                          TASK_UNINTERRUPTIBLE);
4041 }
4042
4043 static const char *alloc_name(u64 flags)
4044 {
4045         switch (flags) {
4046         case BTRFS_BLOCK_GROUP_METADATA|BTRFS_BLOCK_GROUP_DATA:
4047                 return "mixed";
4048         case BTRFS_BLOCK_GROUP_METADATA:
4049                 return "metadata";
4050         case BTRFS_BLOCK_GROUP_DATA:
4051                 return "data";
4052         case BTRFS_BLOCK_GROUP_SYSTEM:
4053                 return "system";
4054         default:
4055                 WARN_ON(1);
4056                 return "invalid-combination";
4057         };
4058 }
4059
4060 static int create_space_info(struct btrfs_fs_info *info, u64 flags,
4061                              struct btrfs_space_info **new)
4062 {
4063
4064         struct btrfs_space_info *space_info;
4065         int i;
4066         int ret;
4067
4068         space_info = kzalloc(sizeof(*space_info), GFP_NOFS);
4069         if (!space_info)
4070                 return -ENOMEM;
4071
4072         ret = percpu_counter_init(&space_info->total_bytes_pinned, 0,
4073                                  GFP_KERNEL);
4074         if (ret) {
4075                 kfree(space_info);
4076                 return ret;
4077         }
4078
4079         for (i = 0; i < BTRFS_NR_RAID_TYPES; i++)
4080                 INIT_LIST_HEAD(&space_info->block_groups[i]);
4081         init_rwsem(&space_info->groups_sem);
4082         spin_lock_init(&space_info->lock);
4083         space_info->flags = flags & BTRFS_BLOCK_GROUP_TYPE_MASK;
4084         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4085         init_waitqueue_head(&space_info->wait);
4086         INIT_LIST_HEAD(&space_info->ro_bgs);
4087         INIT_LIST_HEAD(&space_info->tickets);
4088         INIT_LIST_HEAD(&space_info->priority_tickets);
4089
4090         ret = kobject_init_and_add(&space_info->kobj, &space_info_ktype,
4091                                     info->space_info_kobj, "%s",
4092                                     alloc_name(space_info->flags));
4093         if (ret) {
4094                 kobject_put(&space_info->kobj);
4095                 return ret;
4096         }
4097
4098         *new = space_info;
4099         list_add_rcu(&space_info->list, &info->space_info);
4100         if (flags & BTRFS_BLOCK_GROUP_DATA)
4101                 info->data_sinfo = space_info;
4102
4103         return ret;
4104 }
4105
4106 static void update_space_info(struct btrfs_fs_info *info, u64 flags,
4107                              u64 total_bytes, u64 bytes_used,
4108                              u64 bytes_readonly,
4109                              struct btrfs_space_info **space_info)
4110 {
4111         struct btrfs_space_info *found;
4112         int factor;
4113
4114         if (flags & (BTRFS_BLOCK_GROUP_DUP | BTRFS_BLOCK_GROUP_RAID1 |
4115                      BTRFS_BLOCK_GROUP_RAID10))
4116                 factor = 2;
4117         else
4118                 factor = 1;
4119
4120         found = __find_space_info(info, flags);
4121         ASSERT(found);
4122         spin_lock(&found->lock);
4123         found->total_bytes += total_bytes;
4124         found->disk_total += total_bytes * factor;
4125         found->bytes_used += bytes_used;
4126         found->disk_used += bytes_used * factor;
4127         found->bytes_readonly += bytes_readonly;
4128         if (total_bytes > 0)
4129                 found->full = 0;
4130         space_info_add_new_bytes(info, found, total_bytes -
4131                                  bytes_used - bytes_readonly);
4132         spin_unlock(&found->lock);
4133         *space_info = found;
4134 }
4135
4136 static void set_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
4137 {
4138         u64 extra_flags = chunk_to_extended(flags) &
4139                                 BTRFS_EXTENDED_PROFILE_MASK;
4140
4141         write_seqlock(&fs_info->profiles_lock);
4142         if (flags & BTRFS_BLOCK_GROUP_DATA)
4143                 fs_info->avail_data_alloc_bits |= extra_flags;
4144         if (flags & BTRFS_BLOCK_GROUP_METADATA)
4145                 fs_info->avail_metadata_alloc_bits |= extra_flags;
4146         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4147                 fs_info->avail_system_alloc_bits |= extra_flags;
4148         write_sequnlock(&fs_info->profiles_lock);
4149 }
4150
4151 /*
4152  * returns target flags in extended format or 0 if restripe for this
4153  * chunk_type is not in progress
4154  *
4155  * should be called with either volume_mutex or balance_lock held
4156  */
4157 static u64 get_restripe_target(struct btrfs_fs_info *fs_info, u64 flags)
4158 {
4159         struct btrfs_balance_control *bctl = fs_info->balance_ctl;
4160         u64 target = 0;
4161
4162         if (!bctl)
4163                 return 0;
4164
4165         if (flags & BTRFS_BLOCK_GROUP_DATA &&
4166             bctl->data.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4167                 target = BTRFS_BLOCK_GROUP_DATA | bctl->data.target;
4168         } else if (flags & BTRFS_BLOCK_GROUP_SYSTEM &&
4169                    bctl->sys.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4170                 target = BTRFS_BLOCK_GROUP_SYSTEM | bctl->sys.target;
4171         } else if (flags & BTRFS_BLOCK_GROUP_METADATA &&
4172                    bctl->meta.flags & BTRFS_BALANCE_ARGS_CONVERT) {
4173                 target = BTRFS_BLOCK_GROUP_METADATA | bctl->meta.target;
4174         }
4175
4176         return target;
4177 }
4178
4179 /*
4180  * @flags: available profiles in extended format (see ctree.h)
4181  *
4182  * Returns reduced profile in chunk format.  If profile changing is in
4183  * progress (either running or paused) picks the target profile (if it's
4184  * already available), otherwise falls back to plain reducing.
4185  */
4186 static u64 btrfs_reduce_alloc_profile(struct btrfs_fs_info *fs_info, u64 flags)
4187 {
4188         u64 num_devices = fs_info->fs_devices->rw_devices;
4189         u64 target;
4190         u64 raid_type;
4191         u64 allowed = 0;
4192
4193         /*
4194          * see if restripe for this chunk_type is in progress, if so
4195          * try to reduce to the target profile
4196          */
4197         spin_lock(&fs_info->balance_lock);
4198         target = get_restripe_target(fs_info, flags);
4199         if (target) {
4200                 /* pick target profile only if it's already available */
4201                 if ((flags & target) & BTRFS_EXTENDED_PROFILE_MASK) {
4202                         spin_unlock(&fs_info->balance_lock);
4203                         return extended_to_chunk(target);
4204                 }
4205         }
4206         spin_unlock(&fs_info->balance_lock);
4207
4208         /* First, mask out the RAID levels which aren't possible */
4209         for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4210                 if (num_devices >= btrfs_raid_array[raid_type].devs_min)
4211                         allowed |= btrfs_raid_group[raid_type];
4212         }
4213         allowed &= flags;
4214
4215         if (allowed & BTRFS_BLOCK_GROUP_RAID6)
4216                 allowed = BTRFS_BLOCK_GROUP_RAID6;
4217         else if (allowed & BTRFS_BLOCK_GROUP_RAID5)
4218                 allowed = BTRFS_BLOCK_GROUP_RAID5;
4219         else if (allowed & BTRFS_BLOCK_GROUP_RAID10)
4220                 allowed = BTRFS_BLOCK_GROUP_RAID10;
4221         else if (allowed & BTRFS_BLOCK_GROUP_RAID1)
4222                 allowed = BTRFS_BLOCK_GROUP_RAID1;
4223         else if (allowed & BTRFS_BLOCK_GROUP_RAID0)
4224                 allowed = BTRFS_BLOCK_GROUP_RAID0;
4225
4226         flags &= ~BTRFS_BLOCK_GROUP_PROFILE_MASK;
4227
4228         return extended_to_chunk(flags | allowed);
4229 }
4230
4231 static u64 get_alloc_profile(struct btrfs_fs_info *fs_info, u64 orig_flags)
4232 {
4233         unsigned seq;
4234         u64 flags;
4235
4236         do {
4237                 flags = orig_flags;
4238                 seq = read_seqbegin(&fs_info->profiles_lock);
4239
4240                 if (flags & BTRFS_BLOCK_GROUP_DATA)
4241                         flags |= fs_info->avail_data_alloc_bits;
4242                 else if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
4243                         flags |= fs_info->avail_system_alloc_bits;
4244                 else if (flags & BTRFS_BLOCK_GROUP_METADATA)
4245                         flags |= fs_info->avail_metadata_alloc_bits;
4246         } while (read_seqretry(&fs_info->profiles_lock, seq));
4247
4248         return btrfs_reduce_alloc_profile(fs_info, flags);
4249 }
4250
4251 static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
4252 {
4253         struct btrfs_fs_info *fs_info = root->fs_info;
4254         u64 flags;
4255         u64 ret;
4256
4257         if (data)
4258                 flags = BTRFS_BLOCK_GROUP_DATA;
4259         else if (root == fs_info->chunk_root)
4260                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
4261         else
4262                 flags = BTRFS_BLOCK_GROUP_METADATA;
4263
4264         ret = get_alloc_profile(fs_info, flags);
4265         return ret;
4266 }
4267
4268 u64 btrfs_data_alloc_profile(struct btrfs_fs_info *fs_info)
4269 {
4270         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_DATA);
4271 }
4272
4273 u64 btrfs_metadata_alloc_profile(struct btrfs_fs_info *fs_info)
4274 {
4275         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_METADATA);
4276 }
4277
4278 u64 btrfs_system_alloc_profile(struct btrfs_fs_info *fs_info)
4279 {
4280         return get_alloc_profile(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4281 }
4282
4283 static u64 btrfs_space_info_used(struct btrfs_space_info *s_info,
4284                                  bool may_use_included)
4285 {
4286         ASSERT(s_info);
4287         return s_info->bytes_used + s_info->bytes_reserved +
4288                 s_info->bytes_pinned + s_info->bytes_readonly +
4289                 (may_use_included ? s_info->bytes_may_use : 0);
4290 }
4291
4292 int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode *inode, u64 bytes)
4293 {
4294         struct btrfs_root *root = inode->root;
4295         struct btrfs_fs_info *fs_info = root->fs_info;
4296         struct btrfs_space_info *data_sinfo = fs_info->data_sinfo;
4297         u64 used;
4298         int ret = 0;
4299         int need_commit = 2;
4300         int have_pinned_space;
4301
4302         /* make sure bytes are sectorsize aligned */
4303         bytes = ALIGN(bytes, fs_info->sectorsize);
4304
4305         if (btrfs_is_free_space_inode(inode)) {
4306                 need_commit = 0;
4307                 ASSERT(current->journal_info);
4308         }
4309
4310 again:
4311         /* make sure we have enough space to handle the data first */
4312         spin_lock(&data_sinfo->lock);
4313         used = btrfs_space_info_used(data_sinfo, true);
4314
4315         if (used + bytes > data_sinfo->total_bytes) {
4316                 struct btrfs_trans_handle *trans;
4317
4318                 /*
4319                  * if we don't have enough free bytes in this space then we need
4320                  * to alloc a new chunk.
4321                  */
4322                 if (!data_sinfo->full) {
4323                         u64 alloc_target;
4324
4325                         data_sinfo->force_alloc = CHUNK_ALLOC_FORCE;
4326                         spin_unlock(&data_sinfo->lock);
4327
4328                         alloc_target = btrfs_data_alloc_profile(fs_info);
4329                         /*
4330                          * It is ugly that we don't call nolock join
4331                          * transaction for the free space inode case here.
4332                          * But it is safe because we only do the data space
4333                          * reservation for the free space cache in the
4334                          * transaction context, the common join transaction
4335                          * just increase the counter of the current transaction
4336                          * handler, doesn't try to acquire the trans_lock of
4337                          * the fs.
4338                          */
4339                         trans = btrfs_join_transaction(root);
4340                         if (IS_ERR(trans))
4341                                 return PTR_ERR(trans);
4342
4343                         ret = do_chunk_alloc(trans, fs_info, alloc_target,
4344                                              CHUNK_ALLOC_NO_FORCE);
4345                         btrfs_end_transaction(trans);
4346                         if (ret < 0) {
4347                                 if (ret != -ENOSPC)
4348                                         return ret;
4349                                 else {
4350                                         have_pinned_space = 1;
4351                                         goto commit_trans;
4352                                 }
4353                         }
4354
4355                         goto again;
4356                 }
4357
4358                 /*
4359                  * If we don't have enough pinned space to deal with this
4360                  * allocation, and no removed chunk in current transaction,
4361                  * don't bother committing the transaction.
4362                  */
4363                 have_pinned_space = percpu_counter_compare(
4364                         &data_sinfo->total_bytes_pinned,
4365                         used + bytes - data_sinfo->total_bytes);
4366                 spin_unlock(&data_sinfo->lock);
4367
4368                 /* commit the current transaction and try again */
4369 commit_trans:
4370                 if (need_commit &&
4371                     !atomic_read(&fs_info->open_ioctl_trans)) {
4372                         need_commit--;
4373
4374                         if (need_commit > 0) {
4375                                 btrfs_start_delalloc_roots(fs_info, 0, -1);
4376                                 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0,
4377                                                          (u64)-1);
4378                         }
4379
4380                         trans = btrfs_join_transaction(root);
4381                         if (IS_ERR(trans))
4382                                 return PTR_ERR(trans);
4383                         if (have_pinned_space >= 0 ||
4384                             test_bit(BTRFS_TRANS_HAVE_FREE_BGS,
4385                                      &trans->transaction->flags) ||
4386                             need_commit > 0) {
4387                                 ret = btrfs_commit_transaction(trans);
4388                                 if (ret)
4389                                         return ret;
4390                                 /*
4391                                  * The cleaner kthread might still be doing iput
4392                                  * operations. Wait for it to finish so that
4393                                  * more space is released.
4394                                  */
4395                                 mutex_lock(&fs_info->cleaner_delayed_iput_mutex);
4396                                 mutex_unlock(&fs_info->cleaner_delayed_iput_mutex);
4397                                 goto again;
4398                         } else {
4399                                 btrfs_end_transaction(trans);
4400                         }
4401                 }
4402
4403                 trace_btrfs_space_reservation(fs_info,
4404                                               "space_info:enospc",
4405                                               data_sinfo->flags, bytes, 1);
4406                 return -ENOSPC;
4407         }
4408         data_sinfo->bytes_may_use += bytes;
4409         trace_btrfs_space_reservation(fs_info, "space_info",
4410                                       data_sinfo->flags, bytes, 1);
4411         spin_unlock(&data_sinfo->lock);
4412
4413         return 0;
4414 }
4415
4416 int btrfs_check_data_free_space(struct inode *inode,
4417                         struct extent_changeset **reserved, u64 start, u64 len)
4418 {
4419         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4420         int ret;
4421
4422         /* align the range */
4423         len = round_up(start + len, fs_info->sectorsize) -
4424               round_down(start, fs_info->sectorsize);
4425         start = round_down(start, fs_info->sectorsize);
4426
4427         ret = btrfs_alloc_data_chunk_ondemand(BTRFS_I(inode), len);
4428         if (ret < 0)
4429                 return ret;
4430
4431         /* Use new btrfs_qgroup_reserve_data to reserve precious data space. */
4432         ret = btrfs_qgroup_reserve_data(inode, reserved, start, len);
4433         if (ret < 0)
4434                 btrfs_free_reserved_data_space_noquota(inode, start, len);
4435         else
4436                 ret = 0;
4437         return ret;
4438 }
4439
4440 /*
4441  * Called if we need to clear a data reservation for this inode
4442  * Normally in a error case.
4443  *
4444  * This one will *NOT* use accurate qgroup reserved space API, just for case
4445  * which we can't sleep and is sure it won't affect qgroup reserved space.
4446  * Like clear_bit_hook().
4447  */
4448 void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start,
4449                                             u64 len)
4450 {
4451         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4452         struct btrfs_space_info *data_sinfo;
4453
4454         /* Make sure the range is aligned to sectorsize */
4455         len = round_up(start + len, fs_info->sectorsize) -
4456               round_down(start, fs_info->sectorsize);
4457         start = round_down(start, fs_info->sectorsize);
4458
4459         data_sinfo = fs_info->data_sinfo;
4460         spin_lock(&data_sinfo->lock);
4461         if (WARN_ON(data_sinfo->bytes_may_use < len))
4462                 data_sinfo->bytes_may_use = 0;
4463         else
4464                 data_sinfo->bytes_may_use -= len;
4465         trace_btrfs_space_reservation(fs_info, "space_info",
4466                                       data_sinfo->flags, len, 0);
4467         spin_unlock(&data_sinfo->lock);
4468 }
4469
4470 /*
4471  * Called if we need to clear a data reservation for this inode
4472  * Normally in a error case.
4473  *
4474  * This one will handle the per-inode data rsv map for accurate reserved
4475  * space framework.
4476  */
4477 void btrfs_free_reserved_data_space(struct inode *inode,
4478                         struct extent_changeset *reserved, u64 start, u64 len)
4479 {
4480         struct btrfs_root *root = BTRFS_I(inode)->root;
4481
4482         /* Make sure the range is aligned to sectorsize */
4483         len = round_up(start + len, root->fs_info->sectorsize) -
4484               round_down(start, root->fs_info->sectorsize);
4485         start = round_down(start, root->fs_info->sectorsize);
4486
4487         btrfs_free_reserved_data_space_noquota(inode, start, len);
4488         btrfs_qgroup_free_data(inode, reserved, start, len);
4489 }
4490
4491 static void force_metadata_allocation(struct btrfs_fs_info *info)
4492 {
4493         struct list_head *head = &info->space_info;
4494         struct btrfs_space_info *found;
4495
4496         rcu_read_lock();
4497         list_for_each_entry_rcu(found, head, list) {
4498                 if (found->flags & BTRFS_BLOCK_GROUP_METADATA)
4499                         found->force_alloc = CHUNK_ALLOC_FORCE;
4500         }
4501         rcu_read_unlock();
4502 }
4503
4504 static inline u64 calc_global_rsv_need_space(struct btrfs_block_rsv *global)
4505 {
4506         return (global->size << 1);
4507 }
4508
4509 static int should_alloc_chunk(struct btrfs_fs_info *fs_info,
4510                               struct btrfs_space_info *sinfo, int force)
4511 {
4512         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4513         u64 bytes_used = btrfs_space_info_used(sinfo, false);
4514         u64 thresh;
4515
4516         if (force == CHUNK_ALLOC_FORCE)
4517                 return 1;
4518
4519         /*
4520          * We need to take into account the global rsv because for all intents
4521          * and purposes it's used space.  Don't worry about locking the
4522          * global_rsv, it doesn't change except when the transaction commits.
4523          */
4524         if (sinfo->flags & BTRFS_BLOCK_GROUP_METADATA)
4525                 bytes_used += calc_global_rsv_need_space(global_rsv);
4526
4527         /*
4528          * in limited mode, we want to have some free space up to
4529          * about 1% of the FS size.
4530          */
4531         if (force == CHUNK_ALLOC_LIMITED) {
4532                 thresh = btrfs_super_total_bytes(fs_info->super_copy);
4533                 thresh = max_t(u64, SZ_64M, div_factor_fine(thresh, 1));
4534
4535                 if (sinfo->total_bytes - bytes_used < thresh)
4536                         return 1;
4537         }
4538
4539         if (bytes_used + SZ_2M < div_factor(sinfo->total_bytes, 8))
4540                 return 0;
4541         return 1;
4542 }
4543
4544 static u64 get_profile_num_devs(struct btrfs_fs_info *fs_info, u64 type)
4545 {
4546         u64 num_dev;
4547
4548         if (type & (BTRFS_BLOCK_GROUP_RAID10 |
4549                     BTRFS_BLOCK_GROUP_RAID0 |
4550                     BTRFS_BLOCK_GROUP_RAID5 |
4551                     BTRFS_BLOCK_GROUP_RAID6))
4552                 num_dev = fs_info->fs_devices->rw_devices;
4553         else if (type & BTRFS_BLOCK_GROUP_RAID1)
4554                 num_dev = 2;
4555         else
4556                 num_dev = 1;    /* DUP or single */
4557
4558         return num_dev;
4559 }
4560
4561 /*
4562  * If @is_allocation is true, reserve space in the system space info necessary
4563  * for allocating a chunk, otherwise if it's false, reserve space necessary for
4564  * removing a chunk.
4565  */
4566 void check_system_chunk(struct btrfs_trans_handle *trans,
4567                         struct btrfs_fs_info *fs_info, u64 type)
4568 {
4569         struct btrfs_space_info *info;
4570         u64 left;
4571         u64 thresh;
4572         int ret = 0;
4573         u64 num_devs;
4574
4575         /*
4576          * Needed because we can end up allocating a system chunk and for an
4577          * atomic and race free space reservation in the chunk block reserve.
4578          */
4579         ASSERT(mutex_is_locked(&fs_info->chunk_mutex));
4580
4581         info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
4582         spin_lock(&info->lock);
4583         left = info->total_bytes - btrfs_space_info_used(info, true);
4584         spin_unlock(&info->lock);
4585
4586         num_devs = get_profile_num_devs(fs_info, type);
4587
4588         /* num_devs device items to update and 1 chunk item to add or remove */
4589         thresh = btrfs_calc_trunc_metadata_size(fs_info, num_devs) +
4590                 btrfs_calc_trans_metadata_size(fs_info, 1);
4591
4592         if (left < thresh && btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4593                 btrfs_info(fs_info, "left=%llu, need=%llu, flags=%llu",
4594                            left, thresh, type);
4595                 dump_space_info(fs_info, info, 0, 0);
4596         }
4597
4598         if (left < thresh) {
4599                 u64 flags = btrfs_system_alloc_profile(fs_info);
4600
4601                 /*
4602                  * Ignore failure to create system chunk. We might end up not
4603                  * needing it, as we might not need to COW all nodes/leafs from
4604                  * the paths we visit in the chunk tree (they were already COWed
4605                  * or created in the current transaction for example).
4606                  */
4607                 ret = btrfs_alloc_chunk(trans, fs_info, flags);
4608         }
4609
4610         if (!ret) {
4611                 ret = btrfs_block_rsv_add(fs_info->chunk_root,
4612                                           &fs_info->chunk_block_rsv,
4613                                           thresh, BTRFS_RESERVE_NO_FLUSH);
4614                 if (!ret)
4615                         trans->chunk_bytes_reserved += thresh;
4616         }
4617 }
4618
4619 /*
4620  * If force is CHUNK_ALLOC_FORCE:
4621  *    - return 1 if it successfully allocates a chunk,
4622  *    - return errors including -ENOSPC otherwise.
4623  * If force is NOT CHUNK_ALLOC_FORCE:
4624  *    - return 0 if it doesn't need to allocate a new chunk,
4625  *    - return 1 if it successfully allocates a chunk,
4626  *    - return errors including -ENOSPC otherwise.
4627  */
4628 static int do_chunk_alloc(struct btrfs_trans_handle *trans,
4629                           struct btrfs_fs_info *fs_info, u64 flags, int force)
4630 {
4631         struct btrfs_space_info *space_info;
4632         int wait_for_alloc = 0;
4633         int ret = 0;
4634
4635         /* Don't re-enter if we're already allocating a chunk */
4636         if (trans->allocating_chunk)
4637                 return -ENOSPC;
4638
4639         space_info = __find_space_info(fs_info, flags);
4640         if (!space_info) {
4641                 ret = create_space_info(fs_info, flags, &space_info);
4642                 if (ret)
4643                         return ret;
4644         }
4645
4646 again:
4647         spin_lock(&space_info->lock);
4648         if (force < space_info->force_alloc)
4649                 force = space_info->force_alloc;
4650         if (space_info->full) {
4651                 if (should_alloc_chunk(fs_info, space_info, force))
4652                         ret = -ENOSPC;
4653                 else
4654                         ret = 0;
4655                 spin_unlock(&space_info->lock);
4656                 return ret;
4657         }
4658
4659         if (!should_alloc_chunk(fs_info, space_info, force)) {
4660                 spin_unlock(&space_info->lock);
4661                 return 0;
4662         } else if (space_info->chunk_alloc) {
4663                 wait_for_alloc = 1;
4664         } else {
4665                 space_info->chunk_alloc = 1;
4666         }
4667
4668         spin_unlock(&space_info->lock);
4669
4670         mutex_lock(&fs_info->chunk_mutex);
4671
4672         /*
4673          * The chunk_mutex is held throughout the entirety of a chunk
4674          * allocation, so once we've acquired the chunk_mutex we know that the
4675          * other guy is done and we need to recheck and see if we should
4676          * allocate.
4677          */
4678         if (wait_for_alloc) {
4679                 mutex_unlock(&fs_info->chunk_mutex);
4680                 wait_for_alloc = 0;
4681                 cond_resched();
4682                 goto again;
4683         }
4684
4685         trans->allocating_chunk = true;
4686
4687         /*
4688          * If we have mixed data/metadata chunks we want to make sure we keep
4689          * allocating mixed chunks instead of individual chunks.
4690          */
4691         if (btrfs_mixed_space_info(space_info))
4692                 flags |= (BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA);
4693
4694         /*
4695          * if we're doing a data chunk, go ahead and make sure that
4696          * we keep a reasonable number of metadata chunks allocated in the
4697          * FS as well.
4698          */
4699         if (flags & BTRFS_BLOCK_GROUP_DATA && fs_info->metadata_ratio) {
4700                 fs_info->data_chunk_allocations++;
4701                 if (!(fs_info->data_chunk_allocations %
4702                       fs_info->metadata_ratio))
4703                         force_metadata_allocation(fs_info);
4704         }
4705
4706         /*
4707          * Check if we have enough space in SYSTEM chunk because we may need
4708          * to update devices.
4709          */
4710         check_system_chunk(trans, fs_info, flags);
4711
4712         ret = btrfs_alloc_chunk(trans, fs_info, flags);
4713         trans->allocating_chunk = false;
4714
4715         spin_lock(&space_info->lock);
4716         if (ret < 0 && ret != -ENOSPC)
4717                 goto out;
4718         if (ret)
4719                 space_info->full = 1;
4720         else
4721                 ret = 1;
4722
4723         space_info->force_alloc = CHUNK_ALLOC_NO_FORCE;
4724 out:
4725         space_info->chunk_alloc = 0;
4726         spin_unlock(&space_info->lock);
4727         mutex_unlock(&fs_info->chunk_mutex);
4728         /*
4729          * When we allocate a new chunk we reserve space in the chunk block
4730          * reserve to make sure we can COW nodes/leafs in the chunk tree or
4731          * add new nodes/leafs to it if we end up needing to do it when
4732          * inserting the chunk item and updating device items as part of the
4733          * second phase of chunk allocation, performed by
4734          * btrfs_finish_chunk_alloc(). So make sure we don't accumulate a
4735          * large number of new block groups to create in our transaction
4736          * handle's new_bgs list to avoid exhausting the chunk block reserve
4737          * in extreme cases - like having a single transaction create many new
4738          * block groups when starting to write out the free space caches of all
4739          * the block groups that were made dirty during the lifetime of the
4740          * transaction.
4741          */
4742         if (trans->can_flush_pending_bgs &&
4743             trans->chunk_bytes_reserved >= (u64)SZ_2M) {
4744                 btrfs_create_pending_block_groups(trans, fs_info);
4745                 btrfs_trans_release_chunk_metadata(trans);
4746         }
4747         return ret;
4748 }
4749
4750 static int can_overcommit(struct btrfs_fs_info *fs_info,
4751                           struct btrfs_space_info *space_info, u64 bytes,
4752                           enum btrfs_reserve_flush_enum flush,
4753                           bool system_chunk)
4754 {
4755         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
4756         u64 profile;
4757         u64 space_size;
4758         u64 avail;
4759         u64 used;
4760
4761         /* Don't overcommit when in mixed mode. */
4762         if (space_info->flags & BTRFS_BLOCK_GROUP_DATA)
4763                 return 0;
4764
4765         if (system_chunk)
4766                 profile = btrfs_system_alloc_profile(fs_info);
4767         else
4768                 profile = btrfs_metadata_alloc_profile(fs_info);
4769
4770         used = btrfs_space_info_used(space_info, false);
4771
4772         /*
4773          * We only want to allow over committing if we have lots of actual space
4774          * free, but if we don't have enough space to handle the global reserve
4775          * space then we could end up having a real enospc problem when trying
4776          * to allocate a chunk or some other such important allocation.
4777          */
4778         spin_lock(&global_rsv->lock);
4779         space_size = calc_global_rsv_need_space(global_rsv);
4780         spin_unlock(&global_rsv->lock);
4781         if (used + space_size >= space_info->total_bytes)
4782                 return 0;
4783
4784         used += space_info->bytes_may_use;
4785
4786         avail = atomic64_read(&fs_info->free_chunk_space);
4787
4788         /*
4789          * If we have dup, raid1 or raid10 then only half of the free
4790          * space is actually useable.  For raid56, the space info used
4791          * doesn't include the parity drive, so we don't have to
4792          * change the math
4793          */
4794         if (profile & (BTRFS_BLOCK_GROUP_DUP |
4795                        BTRFS_BLOCK_GROUP_RAID1 |
4796                        BTRFS_BLOCK_GROUP_RAID10))
4797                 avail >>= 1;
4798
4799         /*
4800          * If we aren't flushing all things, let us overcommit up to
4801          * 1/2th of the space. If we can flush, don't let us overcommit
4802          * too much, let it overcommit up to 1/8 of the space.
4803          */
4804         if (flush == BTRFS_RESERVE_FLUSH_ALL)
4805                 avail >>= 3;
4806         else
4807                 avail >>= 1;
4808
4809         if (used + bytes < space_info->total_bytes + avail)
4810                 return 1;
4811         return 0;
4812 }
4813
4814 static void btrfs_writeback_inodes_sb_nr(struct btrfs_fs_info *fs_info,
4815                                          unsigned long nr_pages, int nr_items)
4816 {
4817         struct super_block *sb = fs_info->sb;
4818
4819         if (down_read_trylock(&sb->s_umount)) {
4820                 writeback_inodes_sb_nr(sb, nr_pages, WB_REASON_FS_FREE_SPACE);
4821                 up_read(&sb->s_umount);
4822         } else {
4823                 /*
4824                  * We needn't worry the filesystem going from r/w to r/o though
4825                  * we don't acquire ->s_umount mutex, because the filesystem
4826                  * should guarantee the delalloc inodes list be empty after
4827                  * the filesystem is readonly(all dirty pages are written to
4828                  * the disk).
4829                  */
4830                 btrfs_start_delalloc_roots(fs_info, 0, nr_items);
4831                 if (!current->journal_info)
4832                         btrfs_wait_ordered_roots(fs_info, nr_items, 0, (u64)-1);
4833         }
4834 }
4835
4836 static inline u64 calc_reclaim_items_nr(struct btrfs_fs_info *fs_info,
4837                                         u64 to_reclaim)
4838 {
4839         u64 bytes;
4840         u64 nr;
4841
4842         bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
4843         nr = div64_u64(to_reclaim, bytes);
4844         if (!nr)
4845                 nr = 1;
4846         return nr;
4847 }
4848
4849 #define EXTENT_SIZE_PER_ITEM    SZ_256K
4850
4851 /*
4852  * shrink metadata reservation for delalloc
4853  */
4854 static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim,
4855                             u64 orig, bool wait_ordered)
4856 {
4857         struct btrfs_block_rsv *block_rsv;
4858         struct btrfs_space_info *space_info;
4859         struct btrfs_trans_handle *trans;
4860         u64 delalloc_bytes;
4861         u64 max_reclaim;
4862         u64 items;
4863         long time_left;
4864         unsigned long nr_pages;
4865         int loops;
4866         enum btrfs_reserve_flush_enum flush;
4867
4868         /* Calc the number of the pages we need flush for space reservation */
4869         items = calc_reclaim_items_nr(fs_info, to_reclaim);
4870         to_reclaim = items * EXTENT_SIZE_PER_ITEM;
4871
4872         trans = (struct btrfs_trans_handle *)current->journal_info;
4873         block_rsv = &fs_info->delalloc_block_rsv;
4874         space_info = block_rsv->space_info;
4875
4876         delalloc_bytes = percpu_counter_sum_positive(
4877                                                 &fs_info->delalloc_bytes);
4878         if (delalloc_bytes == 0) {
4879                 if (trans)
4880                         return;
4881                 if (wait_ordered)
4882                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4883                 return;
4884         }
4885
4886         loops = 0;
4887         while (delalloc_bytes && loops < 3) {
4888                 max_reclaim = min(delalloc_bytes, to_reclaim);
4889                 nr_pages = max_reclaim >> PAGE_SHIFT;
4890                 btrfs_writeback_inodes_sb_nr(fs_info, nr_pages, items);
4891                 /*
4892                  * We need to wait for the async pages to actually start before
4893                  * we do anything.
4894                  */
4895                 max_reclaim = atomic_read(&fs_info->async_delalloc_pages);
4896                 if (!max_reclaim)
4897                         goto skip_async;
4898
4899                 if (max_reclaim <= nr_pages)
4900                         max_reclaim = 0;
4901                 else
4902                         max_reclaim -= nr_pages;
4903
4904                 wait_event(fs_info->async_submit_wait,
4905                            atomic_read(&fs_info->async_delalloc_pages) <=
4906                            (int)max_reclaim);
4907 skip_async:
4908                 if (!trans)
4909                         flush = BTRFS_RESERVE_FLUSH_ALL;
4910                 else
4911                         flush = BTRFS_RESERVE_NO_FLUSH;
4912                 spin_lock(&space_info->lock);
4913                 if (list_empty(&space_info->tickets) &&
4914                     list_empty(&space_info->priority_tickets)) {
4915                         spin_unlock(&space_info->lock);
4916                         break;
4917                 }
4918                 spin_unlock(&space_info->lock);
4919
4920                 loops++;
4921                 if (wait_ordered && !trans) {
4922                         btrfs_wait_ordered_roots(fs_info, items, 0, (u64)-1);
4923                 } else {
4924                         time_left = schedule_timeout_killable(1);
4925                         if (time_left)
4926                                 break;
4927                 }
4928                 delalloc_bytes = percpu_counter_sum_positive(
4929                                                 &fs_info->delalloc_bytes);
4930         }
4931 }
4932
4933 struct reserve_ticket {
4934         u64 bytes;
4935         int error;
4936         struct list_head list;
4937         wait_queue_head_t wait;
4938 };
4939
4940 /**
4941  * maybe_commit_transaction - possibly commit the transaction if its ok to
4942  * @root - the root we're allocating for
4943  * @bytes - the number of bytes we want to reserve
4944  * @force - force the commit
4945  *
4946  * This will check to make sure that committing the transaction will actually
4947  * get us somewhere and then commit the transaction if it does.  Otherwise it
4948  * will return -ENOSPC.
4949  */
4950 static int may_commit_transaction(struct btrfs_fs_info *fs_info,
4951                                   struct btrfs_space_info *space_info)
4952 {
4953         struct reserve_ticket *ticket = NULL;
4954         struct btrfs_block_rsv *delayed_rsv = &fs_info->delayed_block_rsv;
4955         struct btrfs_trans_handle *trans;
4956         u64 bytes;
4957
4958         trans = (struct btrfs_trans_handle *)current->journal_info;
4959         if (trans)
4960                 return -EAGAIN;
4961
4962         spin_lock(&space_info->lock);
4963         if (!list_empty(&space_info->priority_tickets))
4964                 ticket = list_first_entry(&space_info->priority_tickets,
4965                                           struct reserve_ticket, list);
4966         else if (!list_empty(&space_info->tickets))
4967                 ticket = list_first_entry(&space_info->tickets,
4968                                           struct reserve_ticket, list);
4969         bytes = (ticket) ? ticket->bytes : 0;
4970         spin_unlock(&space_info->lock);
4971
4972         if (!bytes)
4973                 return 0;
4974
4975         /* See if there is enough pinned space to make this reservation */
4976         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4977                                    bytes) >= 0)
4978                 goto commit;
4979
4980         /*
4981          * See if there is some space in the delayed insertion reservation for
4982          * this reservation.
4983          */
4984         if (space_info != delayed_rsv->space_info)
4985                 return -ENOSPC;
4986
4987         spin_lock(&delayed_rsv->lock);
4988         if (delayed_rsv->size > bytes)
4989                 bytes = 0;
4990         else
4991                 bytes -= delayed_rsv->size;
4992         if (percpu_counter_compare(&space_info->total_bytes_pinned,
4993                                    bytes) < 0) {
4994                 spin_unlock(&delayed_rsv->lock);
4995                 return -ENOSPC;
4996         }
4997         spin_unlock(&delayed_rsv->lock);
4998
4999 commit:
5000         trans = btrfs_join_transaction(fs_info->extent_root);
5001         if (IS_ERR(trans))
5002                 return -ENOSPC;
5003
5004         return btrfs_commit_transaction(trans);
5005 }
5006
5007 /*
5008  * Try to flush some data based on policy set by @state. This is only advisory
5009  * and may fail for various reasons. The caller is supposed to examine the
5010  * state of @space_info to detect the outcome.
5011  */
5012 static void flush_space(struct btrfs_fs_info *fs_info,
5013                        struct btrfs_space_info *space_info, u64 num_bytes,
5014                        int state)
5015 {
5016         struct btrfs_root *root = fs_info->extent_root;
5017         struct btrfs_trans_handle *trans;
5018         int nr;
5019         int ret = 0;
5020
5021         switch (state) {
5022         case FLUSH_DELAYED_ITEMS_NR:
5023         case FLUSH_DELAYED_ITEMS:
5024                 if (state == FLUSH_DELAYED_ITEMS_NR)
5025                         nr = calc_reclaim_items_nr(fs_info, num_bytes) * 2;
5026                 else
5027                         nr = -1;
5028
5029                 trans = btrfs_join_transaction(root);
5030                 if (IS_ERR(trans)) {
5031                         ret = PTR_ERR(trans);
5032                         break;
5033                 }
5034                 ret = btrfs_run_delayed_items_nr(trans, fs_info, nr);
5035                 btrfs_end_transaction(trans);
5036                 break;
5037         case FLUSH_DELALLOC:
5038         case FLUSH_DELALLOC_WAIT:
5039                 shrink_delalloc(fs_info, num_bytes * 2, num_bytes,
5040                                 state == FLUSH_DELALLOC_WAIT);
5041                 break;
5042         case ALLOC_CHUNK:
5043                 trans = btrfs_join_transaction(root);
5044                 if (IS_ERR(trans)) {
5045                         ret = PTR_ERR(trans);
5046                         break;
5047                 }
5048                 ret = do_chunk_alloc(trans, fs_info,
5049                                      btrfs_metadata_alloc_profile(fs_info),
5050                                      CHUNK_ALLOC_NO_FORCE);
5051                 btrfs_end_transaction(trans);
5052                 if (ret > 0 || ret == -ENOSPC)
5053                         ret = 0;
5054                 break;
5055         case COMMIT_TRANS:
5056                 ret = may_commit_transaction(fs_info, space_info);
5057                 break;
5058         default:
5059                 ret = -ENOSPC;
5060                 break;
5061         }
5062
5063         trace_btrfs_flush_space(fs_info, space_info->flags, num_bytes, state,
5064                                 ret);
5065         return;
5066 }
5067
5068 static inline u64
5069 btrfs_calc_reclaim_metadata_size(struct btrfs_fs_info *fs_info,
5070                                  struct btrfs_space_info *space_info,
5071                                  bool system_chunk)
5072 {
5073         struct reserve_ticket *ticket;
5074         u64 used;
5075         u64 expected;
5076         u64 to_reclaim = 0;
5077
5078         list_for_each_entry(ticket, &space_info->tickets, list)
5079                 to_reclaim += ticket->bytes;
5080         list_for_each_entry(ticket, &space_info->priority_tickets, list)
5081                 to_reclaim += ticket->bytes;
5082         if (to_reclaim)
5083                 return to_reclaim;
5084
5085         to_reclaim = min_t(u64, num_online_cpus() * SZ_1M, SZ_16M);
5086         if (can_overcommit(fs_info, space_info, to_reclaim,
5087                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
5088                 return 0;
5089
5090         used = btrfs_space_info_used(space_info, true);
5091
5092         if (can_overcommit(fs_info, space_info, SZ_1M,
5093                            BTRFS_RESERVE_FLUSH_ALL, system_chunk))
5094                 expected = div_factor_fine(space_info->total_bytes, 95);
5095         else
5096                 expected = div_factor_fine(space_info->total_bytes, 90);
5097
5098         if (used > expected)
5099                 to_reclaim = used - expected;
5100         else
5101                 to_reclaim = 0;
5102         to_reclaim = min(to_reclaim, space_info->bytes_may_use +
5103                                      space_info->bytes_reserved);
5104         return to_reclaim;
5105 }
5106
5107 static inline int need_do_async_reclaim(struct btrfs_fs_info *fs_info,
5108                                         struct btrfs_space_info *space_info,
5109                                         u64 used, bool system_chunk)
5110 {
5111         u64 thresh = div_factor_fine(space_info->total_bytes, 98);
5112
5113         /* If we're just plain full then async reclaim just slows us down. */
5114         if ((space_info->bytes_used + space_info->bytes_reserved) >= thresh)
5115                 return 0;
5116
5117         if (!btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5118                                               system_chunk))
5119                 return 0;
5120
5121         return (used >= thresh && !btrfs_fs_closing(fs_info) &&
5122                 !test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state));
5123 }
5124
5125 static void wake_all_tickets(struct list_head *head)
5126 {
5127         struct reserve_ticket *ticket;
5128
5129         while (!list_empty(head)) {
5130                 ticket = list_first_entry(head, struct reserve_ticket, list);
5131                 list_del_init(&ticket->list);
5132                 ticket->error = -ENOSPC;
5133                 wake_up(&ticket->wait);
5134         }
5135 }
5136
5137 /*
5138  * This is for normal flushers, we can wait all goddamned day if we want to.  We
5139  * will loop and continuously try to flush as long as we are making progress.
5140  * We count progress as clearing off tickets each time we have to loop.
5141  */
5142 static void btrfs_async_reclaim_metadata_space(struct work_struct *work)
5143 {
5144         struct btrfs_fs_info *fs_info;
5145         struct btrfs_space_info *space_info;
5146         u64 to_reclaim;
5147         int flush_state;
5148         int commit_cycles = 0;
5149         u64 last_tickets_id;
5150
5151         fs_info = container_of(work, struct btrfs_fs_info, async_reclaim_work);
5152         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5153
5154         spin_lock(&space_info->lock);
5155         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5156                                                       false);
5157         if (!to_reclaim) {
5158                 space_info->flush = 0;
5159                 spin_unlock(&space_info->lock);
5160                 return;
5161         }
5162         last_tickets_id = space_info->tickets_id;
5163         spin_unlock(&space_info->lock);
5164
5165         flush_state = FLUSH_DELAYED_ITEMS_NR;
5166         do {
5167                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5168                 spin_lock(&space_info->lock);
5169                 if (list_empty(&space_info->tickets)) {
5170                         space_info->flush = 0;
5171                         spin_unlock(&space_info->lock);
5172                         return;
5173                 }
5174                 to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info,
5175                                                               space_info,
5176                                                               false);
5177                 if (last_tickets_id == space_info->tickets_id) {
5178                         flush_state++;
5179                 } else {
5180                         last_tickets_id = space_info->tickets_id;
5181                         flush_state = FLUSH_DELAYED_ITEMS_NR;
5182                         if (commit_cycles)
5183                                 commit_cycles--;
5184                 }
5185
5186                 if (flush_state > COMMIT_TRANS) {
5187                         commit_cycles++;
5188                         if (commit_cycles > 2) {
5189                                 wake_all_tickets(&space_info->tickets);
5190                                 space_info->flush = 0;
5191                         } else {
5192                                 flush_state = FLUSH_DELAYED_ITEMS_NR;
5193                         }
5194                 }
5195                 spin_unlock(&space_info->lock);
5196         } while (flush_state <= COMMIT_TRANS);
5197 }
5198
5199 void btrfs_init_async_reclaim_work(struct work_struct *work)
5200 {
5201         INIT_WORK(work, btrfs_async_reclaim_metadata_space);
5202 }
5203
5204 static void priority_reclaim_metadata_space(struct btrfs_fs_info *fs_info,
5205                                             struct btrfs_space_info *space_info,
5206                                             struct reserve_ticket *ticket)
5207 {
5208         u64 to_reclaim;
5209         int flush_state = FLUSH_DELAYED_ITEMS_NR;
5210
5211         spin_lock(&space_info->lock);
5212         to_reclaim = btrfs_calc_reclaim_metadata_size(fs_info, space_info,
5213                                                       false);
5214         if (!to_reclaim) {
5215                 spin_unlock(&space_info->lock);
5216                 return;
5217         }
5218         spin_unlock(&space_info->lock);
5219
5220         do {
5221                 flush_space(fs_info, space_info, to_reclaim, flush_state);
5222                 flush_state++;
5223                 spin_lock(&space_info->lock);
5224                 if (ticket->bytes == 0) {
5225                         spin_unlock(&space_info->lock);
5226                         return;
5227                 }
5228                 spin_unlock(&space_info->lock);
5229
5230                 /*
5231                  * Priority flushers can't wait on delalloc without
5232                  * deadlocking.
5233                  */
5234                 if (flush_state == FLUSH_DELALLOC ||
5235                     flush_state == FLUSH_DELALLOC_WAIT)
5236                         flush_state = ALLOC_CHUNK;
5237         } while (flush_state < COMMIT_TRANS);
5238 }
5239
5240 static int wait_reserve_ticket(struct btrfs_fs_info *fs_info,
5241                                struct btrfs_space_info *space_info,
5242                                struct reserve_ticket *ticket, u64 orig_bytes)
5243
5244 {
5245         DEFINE_WAIT(wait);
5246         int ret = 0;
5247
5248         spin_lock(&space_info->lock);
5249         while (ticket->bytes > 0 && ticket->error == 0) {
5250                 ret = prepare_to_wait_event(&ticket->wait, &wait, TASK_KILLABLE);
5251                 if (ret) {
5252                         ret = -EINTR;
5253                         break;
5254                 }
5255                 spin_unlock(&space_info->lock);
5256
5257                 schedule();
5258
5259                 finish_wait(&ticket->wait, &wait);
5260                 spin_lock(&space_info->lock);
5261         }
5262         if (!ret)
5263                 ret = ticket->error;
5264         if (!list_empty(&ticket->list))
5265                 list_del_init(&ticket->list);
5266         if (ticket->bytes && ticket->bytes < orig_bytes) {
5267                 u64 num_bytes = orig_bytes - ticket->bytes;
5268                 space_info->bytes_may_use -= num_bytes;
5269                 trace_btrfs_space_reservation(fs_info, "space_info",
5270                                               space_info->flags, num_bytes, 0);
5271         }
5272         spin_unlock(&space_info->lock);
5273
5274         return ret;
5275 }
5276
5277 /**
5278  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5279  * @root - the root we're allocating for
5280  * @space_info - the space info we want to allocate from
5281  * @orig_bytes - the number of bytes we want
5282  * @flush - whether or not we can flush to make our reservation
5283  *
5284  * This will reserve orig_bytes number of bytes from the space info associated
5285  * with the block_rsv.  If there is not enough space it will make an attempt to
5286  * flush out space to make room.  It will do this by flushing delalloc if
5287  * possible or committing the transaction.  If flush is 0 then no attempts to
5288  * regain reservations will be made and this will fail if there is not enough
5289  * space already.
5290  */
5291 static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info,
5292                                     struct btrfs_space_info *space_info,
5293                                     u64 orig_bytes,
5294                                     enum btrfs_reserve_flush_enum flush,
5295                                     bool system_chunk)
5296 {
5297         struct reserve_ticket ticket;
5298         u64 used;
5299         int ret = 0;
5300
5301         ASSERT(orig_bytes);
5302         ASSERT(!current->journal_info || flush != BTRFS_RESERVE_FLUSH_ALL);
5303
5304         spin_lock(&space_info->lock);
5305         ret = -ENOSPC;
5306         used = btrfs_space_info_used(space_info, true);
5307
5308         /*
5309          * If we have enough space then hooray, make our reservation and carry
5310          * on.  If not see if we can overcommit, and if we can, hooray carry on.
5311          * If not things get more complicated.
5312          */
5313         if (used + orig_bytes <= space_info->total_bytes) {
5314                 space_info->bytes_may_use += orig_bytes;
5315                 trace_btrfs_space_reservation(fs_info, "space_info",
5316                                               space_info->flags, orig_bytes, 1);
5317                 ret = 0;
5318         } else if (can_overcommit(fs_info, space_info, orig_bytes, flush,
5319                                   system_chunk)) {
5320                 space_info->bytes_may_use += orig_bytes;
5321                 trace_btrfs_space_reservation(fs_info, "space_info",
5322                                               space_info->flags, orig_bytes, 1);
5323                 ret = 0;
5324         }
5325
5326         /*
5327          * If we couldn't make a reservation then setup our reservation ticket
5328          * and kick the async worker if it's not already running.
5329          *
5330          * If we are a priority flusher then we just need to add our ticket to
5331          * the list and we will do our own flushing further down.
5332          */
5333         if (ret && flush != BTRFS_RESERVE_NO_FLUSH) {
5334                 ticket.bytes = orig_bytes;
5335                 ticket.error = 0;
5336                 init_waitqueue_head(&ticket.wait);
5337                 if (flush == BTRFS_RESERVE_FLUSH_ALL) {
5338                         list_add_tail(&ticket.list, &space_info->tickets);
5339                         if (!space_info->flush) {
5340                                 space_info->flush = 1;
5341                                 trace_btrfs_trigger_flush(fs_info,
5342                                                           space_info->flags,
5343                                                           orig_bytes, flush,
5344                                                           "enospc");
5345                                 queue_work(system_unbound_wq,
5346                                            &fs_info->async_reclaim_work);
5347                         }
5348                 } else {
5349                         list_add_tail(&ticket.list,
5350                                       &space_info->priority_tickets);
5351                 }
5352         } else if (!ret && space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
5353                 used += orig_bytes;
5354                 /*
5355                  * We will do the space reservation dance during log replay,
5356                  * which means we won't have fs_info->fs_root set, so don't do
5357                  * the async reclaim as we will panic.
5358                  */
5359                 if (!test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags) &&
5360                     need_do_async_reclaim(fs_info, space_info,
5361                                           used, system_chunk) &&
5362                     !work_busy(&fs_info->async_reclaim_work)) {
5363                         trace_btrfs_trigger_flush(fs_info, space_info->flags,
5364                                                   orig_bytes, flush, "preempt");
5365                         queue_work(system_unbound_wq,
5366                                    &fs_info->async_reclaim_work);
5367                 }
5368         }
5369         spin_unlock(&space_info->lock);
5370         if (!ret || flush == BTRFS_RESERVE_NO_FLUSH)
5371                 return ret;
5372
5373         if (flush == BTRFS_RESERVE_FLUSH_ALL)
5374                 return wait_reserve_ticket(fs_info, space_info, &ticket,
5375                                            orig_bytes);
5376
5377         ret = 0;
5378         priority_reclaim_metadata_space(fs_info, space_info, &ticket);
5379         spin_lock(&space_info->lock);
5380         if (ticket.bytes) {
5381                 if (ticket.bytes < orig_bytes) {
5382                         u64 num_bytes = orig_bytes - ticket.bytes;
5383                         space_info->bytes_may_use -= num_bytes;
5384                         trace_btrfs_space_reservation(fs_info, "space_info",
5385                                                       space_info->flags,
5386                                                       num_bytes, 0);
5387
5388                 }
5389                 list_del_init(&ticket.list);
5390                 ret = -ENOSPC;
5391         }
5392         spin_unlock(&space_info->lock);
5393         ASSERT(list_empty(&ticket.list));
5394         return ret;
5395 }
5396
5397 /**
5398  * reserve_metadata_bytes - try to reserve bytes from the block_rsv's space
5399  * @root - the root we're allocating for
5400  * @block_rsv - the block_rsv we're allocating for
5401  * @orig_bytes - the number of bytes we want
5402  * @flush - whether or not we can flush to make our reservation
5403  *
5404  * This will reserve orgi_bytes number of bytes from the space info associated
5405  * with the block_rsv.  If there is not enough space it will make an attempt to
5406  * flush out space to make room.  It will do this by flushing delalloc if
5407  * possible or committing the transaction.  If flush is 0 then no attempts to
5408  * regain reservations will be made and this will fail if there is not enough
5409  * space already.
5410  */
5411 static int reserve_metadata_bytes(struct btrfs_root *root,
5412                                   struct btrfs_block_rsv *block_rsv,
5413                                   u64 orig_bytes,
5414                                   enum btrfs_reserve_flush_enum flush)
5415 {
5416         struct btrfs_fs_info *fs_info = root->fs_info;
5417         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5418         int ret;
5419         bool system_chunk = (root == fs_info->chunk_root);
5420
5421         ret = __reserve_metadata_bytes(fs_info, block_rsv->space_info,
5422                                        orig_bytes, flush, system_chunk);
5423         if (ret == -ENOSPC &&
5424             unlikely(root->orphan_cleanup_state == ORPHAN_CLEANUP_STARTED)) {
5425                 if (block_rsv != global_rsv &&
5426                     !block_rsv_use_bytes(global_rsv, orig_bytes))
5427                         ret = 0;
5428         }
5429         if (ret == -ENOSPC)
5430                 trace_btrfs_space_reservation(fs_info, "space_info:enospc",
5431                                               block_rsv->space_info->flags,
5432                                               orig_bytes, 1);
5433         return ret;
5434 }
5435
5436 static struct btrfs_block_rsv *get_block_rsv(
5437                                         const struct btrfs_trans_handle *trans,
5438                                         const struct btrfs_root *root)
5439 {
5440         struct btrfs_fs_info *fs_info = root->fs_info;
5441         struct btrfs_block_rsv *block_rsv = NULL;
5442
5443         if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
5444             (root == fs_info->csum_root && trans->adding_csums) ||
5445             (root == fs_info->uuid_root))
5446                 block_rsv = trans->block_rsv;
5447
5448         if (!block_rsv)
5449                 block_rsv = root->block_rsv;
5450
5451         if (!block_rsv)
5452                 block_rsv = &fs_info->empty_block_rsv;
5453
5454         return block_rsv;
5455 }
5456
5457 static int block_rsv_use_bytes(struct btrfs_block_rsv *block_rsv,
5458                                u64 num_bytes)
5459 {
5460         int ret = -ENOSPC;
5461         spin_lock(&block_rsv->lock);
5462         if (block_rsv->reserved >= num_bytes) {
5463                 block_rsv->reserved -= num_bytes;
5464                 if (block_rsv->reserved < block_rsv->size)
5465                         block_rsv->full = 0;
5466                 ret = 0;
5467         }
5468         spin_unlock(&block_rsv->lock);
5469         return ret;
5470 }
5471
5472 static void block_rsv_add_bytes(struct btrfs_block_rsv *block_rsv,
5473                                 u64 num_bytes, int update_size)
5474 {
5475         spin_lock(&block_rsv->lock);
5476         block_rsv->reserved += num_bytes;
5477         if (update_size)
5478                 block_rsv->size += num_bytes;
5479         else if (block_rsv->reserved >= block_rsv->size)
5480                 block_rsv->full = 1;
5481         spin_unlock(&block_rsv->lock);
5482 }
5483
5484 int btrfs_cond_migrate_bytes(struct btrfs_fs_info *fs_info,
5485                              struct btrfs_block_rsv *dest, u64 num_bytes,
5486                              int min_factor)
5487 {
5488         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5489         u64 min_bytes;
5490
5491         if (global_rsv->space_info != dest->space_info)
5492                 return -ENOSPC;
5493
5494         spin_lock(&global_rsv->lock);
5495         min_bytes = div_factor(global_rsv->size, min_factor);
5496         if (global_rsv->reserved < min_bytes + num_bytes) {
5497                 spin_unlock(&global_rsv->lock);
5498                 return -ENOSPC;
5499         }
5500         global_rsv->reserved -= num_bytes;
5501         if (global_rsv->reserved < global_rsv->size)
5502                 global_rsv->full = 0;
5503         spin_unlock(&global_rsv->lock);
5504
5505         block_rsv_add_bytes(dest, num_bytes, 1);
5506         return 0;
5507 }
5508
5509 /*
5510  * This is for space we already have accounted in space_info->bytes_may_use, so
5511  * basically when we're returning space from block_rsv's.
5512  */
5513 static void space_info_add_old_bytes(struct btrfs_fs_info *fs_info,
5514                                      struct btrfs_space_info *space_info,
5515                                      u64 num_bytes)
5516 {
5517         struct reserve_ticket *ticket;
5518         struct list_head *head;
5519         u64 used;
5520         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_NO_FLUSH;
5521         bool check_overcommit = false;
5522
5523         spin_lock(&space_info->lock);
5524         head = &space_info->priority_tickets;
5525
5526         /*
5527          * If we are over our limit then we need to check and see if we can
5528          * overcommit, and if we can't then we just need to free up our space
5529          * and not satisfy any requests.
5530          */
5531         used = btrfs_space_info_used(space_info, true);
5532         if (used - num_bytes >= space_info->total_bytes)
5533                 check_overcommit = true;
5534 again:
5535         while (!list_empty(head) && num_bytes) {
5536                 ticket = list_first_entry(head, struct reserve_ticket,
5537                                           list);
5538                 /*
5539                  * We use 0 bytes because this space is already reserved, so
5540                  * adding the ticket space would be a double count.
5541                  */
5542                 if (check_overcommit &&
5543                     !can_overcommit(fs_info, space_info, 0, flush, false))
5544                         break;
5545                 if (num_bytes >= ticket->bytes) {
5546                         list_del_init(&ticket->list);
5547                         num_bytes -= ticket->bytes;
5548                         ticket->bytes = 0;
5549                         space_info->tickets_id++;
5550                         wake_up(&ticket->wait);
5551                 } else {
5552                         ticket->bytes -= num_bytes;
5553                         num_bytes = 0;
5554                 }
5555         }
5556
5557         if (num_bytes && head == &space_info->priority_tickets) {
5558                 head = &space_info->tickets;
5559                 flush = BTRFS_RESERVE_FLUSH_ALL;
5560                 goto again;
5561         }
5562         space_info->bytes_may_use -= num_bytes;
5563         trace_btrfs_space_reservation(fs_info, "space_info",
5564                                       space_info->flags, num_bytes, 0);
5565         spin_unlock(&space_info->lock);
5566 }
5567
5568 /*
5569  * This is for newly allocated space that isn't accounted in
5570  * space_info->bytes_may_use yet.  So if we allocate a chunk or unpin an extent
5571  * we use this helper.
5572  */
5573 static void space_info_add_new_bytes(struct btrfs_fs_info *fs_info,
5574                                      struct btrfs_space_info *space_info,
5575                                      u64 num_bytes)
5576 {
5577         struct reserve_ticket *ticket;
5578         struct list_head *head = &space_info->priority_tickets;
5579
5580 again:
5581         while (!list_empty(head) && num_bytes) {
5582                 ticket = list_first_entry(head, struct reserve_ticket,
5583                                           list);
5584                 if (num_bytes >= ticket->bytes) {
5585                         trace_btrfs_space_reservation(fs_info, "space_info",
5586                                                       space_info->flags,
5587                                                       ticket->bytes, 1);
5588                         list_del_init(&ticket->list);
5589                         num_bytes -= ticket->bytes;
5590                         space_info->bytes_may_use += ticket->bytes;
5591                         ticket->bytes = 0;
5592                         space_info->tickets_id++;
5593                         wake_up(&ticket->wait);
5594                 } else {
5595                         trace_btrfs_space_reservation(fs_info, "space_info",
5596                                                       space_info->flags,
5597                                                       num_bytes, 1);
5598                         space_info->bytes_may_use += num_bytes;
5599                         ticket->bytes -= num_bytes;
5600                         num_bytes = 0;
5601                 }
5602         }
5603
5604         if (num_bytes && head == &space_info->priority_tickets) {
5605                 head = &space_info->tickets;
5606                 goto again;
5607         }
5608 }
5609
5610 static void block_rsv_release_bytes(struct btrfs_fs_info *fs_info,
5611                                     struct btrfs_block_rsv *block_rsv,
5612                                     struct btrfs_block_rsv *dest, u64 num_bytes)
5613 {
5614         struct btrfs_space_info *space_info = block_rsv->space_info;
5615
5616         spin_lock(&block_rsv->lock);
5617         if (num_bytes == (u64)-1)
5618                 num_bytes = block_rsv->size;
5619         block_rsv->size -= num_bytes;
5620         if (block_rsv->reserved >= block_rsv->size) {
5621                 num_bytes = block_rsv->reserved - block_rsv->size;
5622                 block_rsv->reserved = block_rsv->size;
5623                 block_rsv->full = 1;
5624         } else {
5625                 num_bytes = 0;
5626         }
5627         spin_unlock(&block_rsv->lock);
5628
5629         if (num_bytes > 0) {
5630                 if (dest) {
5631                         spin_lock(&dest->lock);
5632                         if (!dest->full) {
5633                                 u64 bytes_to_add;
5634
5635                                 bytes_to_add = dest->size - dest->reserved;
5636                                 bytes_to_add = min(num_bytes, bytes_to_add);
5637                                 dest->reserved += bytes_to_add;
5638                                 if (dest->reserved >= dest->size)
5639                                         dest->full = 1;
5640                                 num_bytes -= bytes_to_add;
5641                         }
5642                         spin_unlock(&dest->lock);
5643                 }
5644                 if (num_bytes)
5645                         space_info_add_old_bytes(fs_info, space_info,
5646                                                  num_bytes);
5647         }
5648 }
5649
5650 int btrfs_block_rsv_migrate(struct btrfs_block_rsv *src,
5651                             struct btrfs_block_rsv *dst, u64 num_bytes,
5652                             int update_size)
5653 {
5654         int ret;
5655
5656         ret = block_rsv_use_bytes(src, num_bytes);
5657         if (ret)
5658                 return ret;
5659
5660         block_rsv_add_bytes(dst, num_bytes, update_size);
5661         return 0;
5662 }
5663
5664 void btrfs_init_block_rsv(struct btrfs_block_rsv *rsv, unsigned short type)
5665 {
5666         memset(rsv, 0, sizeof(*rsv));
5667         spin_lock_init(&rsv->lock);
5668         rsv->type = type;
5669 }
5670
5671 struct btrfs_block_rsv *btrfs_alloc_block_rsv(struct btrfs_fs_info *fs_info,
5672                                               unsigned short type)
5673 {
5674         struct btrfs_block_rsv *block_rsv;
5675
5676         block_rsv = kmalloc(sizeof(*block_rsv), GFP_NOFS);
5677         if (!block_rsv)
5678                 return NULL;
5679
5680         btrfs_init_block_rsv(block_rsv, type);
5681         block_rsv->space_info = __find_space_info(fs_info,
5682                                                   BTRFS_BLOCK_GROUP_METADATA);
5683         return block_rsv;
5684 }
5685
5686 void btrfs_free_block_rsv(struct btrfs_fs_info *fs_info,
5687                           struct btrfs_block_rsv *rsv)
5688 {
5689         if (!rsv)
5690                 return;
5691         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5692         kfree(rsv);
5693 }
5694
5695 void __btrfs_free_block_rsv(struct btrfs_block_rsv *rsv)
5696 {
5697         kfree(rsv);
5698 }
5699
5700 int btrfs_block_rsv_add(struct btrfs_root *root,
5701                         struct btrfs_block_rsv *block_rsv, u64 num_bytes,
5702                         enum btrfs_reserve_flush_enum flush)
5703 {
5704         int ret;
5705
5706         if (num_bytes == 0)
5707                 return 0;
5708
5709         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5710         if (!ret) {
5711                 block_rsv_add_bytes(block_rsv, num_bytes, 1);
5712                 return 0;
5713         }
5714
5715         return ret;
5716 }
5717
5718 int btrfs_block_rsv_check(struct btrfs_block_rsv *block_rsv, int min_factor)
5719 {
5720         u64 num_bytes = 0;
5721         int ret = -ENOSPC;
5722
5723         if (!block_rsv)
5724                 return 0;
5725
5726         spin_lock(&block_rsv->lock);
5727         num_bytes = div_factor(block_rsv->size, min_factor);
5728         if (block_rsv->reserved >= num_bytes)
5729                 ret = 0;
5730         spin_unlock(&block_rsv->lock);
5731
5732         return ret;
5733 }
5734
5735 int btrfs_block_rsv_refill(struct btrfs_root *root,
5736                            struct btrfs_block_rsv *block_rsv, u64 min_reserved,
5737                            enum btrfs_reserve_flush_enum flush)
5738 {
5739         u64 num_bytes = 0;
5740         int ret = -ENOSPC;
5741
5742         if (!block_rsv)
5743                 return 0;
5744
5745         spin_lock(&block_rsv->lock);
5746         num_bytes = min_reserved;
5747         if (block_rsv->reserved >= num_bytes)
5748                 ret = 0;
5749         else
5750                 num_bytes -= block_rsv->reserved;
5751         spin_unlock(&block_rsv->lock);
5752
5753         if (!ret)
5754                 return 0;
5755
5756         ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
5757         if (!ret) {
5758                 block_rsv_add_bytes(block_rsv, num_bytes, 0);
5759                 return 0;
5760         }
5761
5762         return ret;
5763 }
5764
5765 void btrfs_block_rsv_release(struct btrfs_fs_info *fs_info,
5766                              struct btrfs_block_rsv *block_rsv,
5767                              u64 num_bytes)
5768 {
5769         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5770
5771         if (global_rsv == block_rsv ||
5772             block_rsv->space_info != global_rsv->space_info)
5773                 global_rsv = NULL;
5774         block_rsv_release_bytes(fs_info, block_rsv, global_rsv, num_bytes);
5775 }
5776
5777 static void update_global_block_rsv(struct btrfs_fs_info *fs_info)
5778 {
5779         struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
5780         struct btrfs_space_info *sinfo = block_rsv->space_info;
5781         u64 num_bytes;
5782
5783         /*
5784          * The global block rsv is based on the size of the extent tree, the
5785          * checksum tree and the root tree.  If the fs is empty we want to set
5786          * it to a minimal amount for safety.
5787          */
5788         num_bytes = btrfs_root_used(&fs_info->extent_root->root_item) +
5789                 btrfs_root_used(&fs_info->csum_root->root_item) +
5790                 btrfs_root_used(&fs_info->tree_root->root_item);
5791         num_bytes = max_t(u64, num_bytes, SZ_16M);
5792
5793         spin_lock(&sinfo->lock);
5794         spin_lock(&block_rsv->lock);
5795
5796         block_rsv->size = min_t(u64, num_bytes, SZ_512M);
5797
5798         if (block_rsv->reserved < block_rsv->size) {
5799                 num_bytes = btrfs_space_info_used(sinfo, true);
5800                 if (sinfo->total_bytes > num_bytes) {
5801                         num_bytes = sinfo->total_bytes - num_bytes;
5802                         num_bytes = min(num_bytes,
5803                                         block_rsv->size - block_rsv->reserved);
5804                         block_rsv->reserved += num_bytes;
5805                         sinfo->bytes_may_use += num_bytes;
5806                         trace_btrfs_space_reservation(fs_info, "space_info",
5807                                                       sinfo->flags, num_bytes,
5808                                                       1);
5809                 }
5810         } else if (block_rsv->reserved > block_rsv->size) {
5811                 num_bytes = block_rsv->reserved - block_rsv->size;
5812                 sinfo->bytes_may_use -= num_bytes;
5813                 trace_btrfs_space_reservation(fs_info, "space_info",
5814                                       sinfo->flags, num_bytes, 0);
5815                 block_rsv->reserved = block_rsv->size;
5816         }
5817
5818         if (block_rsv->reserved == block_rsv->size)
5819                 block_rsv->full = 1;
5820         else
5821                 block_rsv->full = 0;
5822
5823         spin_unlock(&block_rsv->lock);
5824         spin_unlock(&sinfo->lock);
5825 }
5826
5827 static void init_global_block_rsv(struct btrfs_fs_info *fs_info)
5828 {
5829         struct btrfs_space_info *space_info;
5830
5831         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_SYSTEM);
5832         fs_info->chunk_block_rsv.space_info = space_info;
5833
5834         space_info = __find_space_info(fs_info, BTRFS_BLOCK_GROUP_METADATA);
5835         fs_info->global_block_rsv.space_info = space_info;
5836         fs_info->delalloc_block_rsv.space_info = space_info;
5837         fs_info->trans_block_rsv.space_info = space_info;
5838         fs_info->empty_block_rsv.space_info = space_info;
5839         fs_info->delayed_block_rsv.space_info = space_info;
5840
5841         fs_info->extent_root->block_rsv = &fs_info->global_block_rsv;
5842         fs_info->csum_root->block_rsv = &fs_info->global_block_rsv;
5843         fs_info->dev_root->block_rsv = &fs_info->global_block_rsv;
5844         fs_info->tree_root->block_rsv = &fs_info->global_block_rsv;
5845         if (fs_info->quota_root)
5846                 fs_info->quota_root->block_rsv = &fs_info->global_block_rsv;
5847         fs_info->chunk_root->block_rsv = &fs_info->chunk_block_rsv;
5848
5849         update_global_block_rsv(fs_info);
5850 }
5851
5852 static void release_global_block_rsv(struct btrfs_fs_info *fs_info)
5853 {
5854         block_rsv_release_bytes(fs_info, &fs_info->global_block_rsv, NULL,
5855                                 (u64)-1);
5856         WARN_ON(fs_info->delalloc_block_rsv.size > 0);
5857         WARN_ON(fs_info->delalloc_block_rsv.reserved > 0);
5858         WARN_ON(fs_info->trans_block_rsv.size > 0);
5859         WARN_ON(fs_info->trans_block_rsv.reserved > 0);
5860         WARN_ON(fs_info->chunk_block_rsv.size > 0);
5861         WARN_ON(fs_info->chunk_block_rsv.reserved > 0);
5862         WARN_ON(fs_info->delayed_block_rsv.size > 0);
5863         WARN_ON(fs_info->delayed_block_rsv.reserved > 0);
5864 }
5865
5866 void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans,
5867                                   struct btrfs_fs_info *fs_info)
5868 {
5869         if (!trans->block_rsv)
5870                 return;
5871
5872         if (!trans->bytes_reserved)
5873                 return;
5874
5875         trace_btrfs_space_reservation(fs_info, "transaction",
5876                                       trans->transid, trans->bytes_reserved, 0);
5877         btrfs_block_rsv_release(fs_info, trans->block_rsv,
5878                                 trans->bytes_reserved);
5879         trans->bytes_reserved = 0;
5880 }
5881
5882 /*
5883  * To be called after all the new block groups attached to the transaction
5884  * handle have been created (btrfs_create_pending_block_groups()).
5885  */
5886 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
5887 {
5888         struct btrfs_fs_info *fs_info = trans->fs_info;
5889
5890         if (!trans->chunk_bytes_reserved)
5891                 return;
5892
5893         WARN_ON_ONCE(!list_empty(&trans->new_bgs));
5894
5895         block_rsv_release_bytes(fs_info, &fs_info->chunk_block_rsv, NULL,
5896                                 trans->chunk_bytes_reserved);
5897         trans->chunk_bytes_reserved = 0;
5898 }
5899
5900 /* Can only return 0 or -ENOSPC */
5901 int btrfs_orphan_reserve_metadata(struct btrfs_trans_handle *trans,
5902                                   struct btrfs_inode *inode)
5903 {
5904         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
5905         struct btrfs_root *root = inode->root;
5906         /*
5907          * We always use trans->block_rsv here as we will have reserved space
5908          * for our orphan when starting the transaction, using get_block_rsv()
5909          * here will sometimes make us choose the wrong block rsv as we could be
5910          * doing a reloc inode for a non refcounted root.
5911          */
5912         struct btrfs_block_rsv *src_rsv = trans->block_rsv;
5913         struct btrfs_block_rsv *dst_rsv = root->orphan_block_rsv;
5914
5915         /*
5916          * We need to hold space in order to delete our orphan item once we've
5917          * added it, so this takes the reservation so we can release it later
5918          * when we are truly done with the orphan item.
5919          */
5920         u64 num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
5921
5922         trace_btrfs_space_reservation(fs_info, "orphan", btrfs_ino(inode),
5923                         num_bytes, 1);
5924         return btrfs_block_rsv_migrate(src_rsv, dst_rsv, num_bytes, 1);
5925 }
5926
5927 void btrfs_orphan_release_metadata(struct btrfs_inode *inode)
5928 {
5929         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
5930         struct btrfs_root *root = inode->root;
5931         u64 num_bytes = btrfs_calc_trans_metadata_size(fs_info, 1);
5932
5933         trace_btrfs_space_reservation(fs_info, "orphan", btrfs_ino(inode),
5934                         num_bytes, 0);
5935         btrfs_block_rsv_release(fs_info, root->orphan_block_rsv, num_bytes);
5936 }
5937
5938 /*
5939  * btrfs_subvolume_reserve_metadata() - reserve space for subvolume operation
5940  * root: the root of the parent directory
5941  * rsv: block reservation
5942  * items: the number of items that we need do reservation
5943  * qgroup_reserved: used to return the reserved size in qgroup
5944  *
5945  * This function is used to reserve the space for snapshot/subvolume
5946  * creation and deletion. Those operations are different with the
5947  * common file/directory operations, they change two fs/file trees
5948  * and root tree, the number of items that the qgroup reserves is
5949  * different with the free space reservation. So we can not use
5950  * the space reservation mechanism in start_transaction().
5951  */
5952 int btrfs_subvolume_reserve_metadata(struct btrfs_root *root,
5953                                      struct btrfs_block_rsv *rsv,
5954                                      int items,
5955                                      u64 *qgroup_reserved,
5956                                      bool use_global_rsv)
5957 {
5958         u64 num_bytes;
5959         int ret;
5960         struct btrfs_fs_info *fs_info = root->fs_info;
5961         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
5962
5963         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
5964                 /* One for parent inode, two for dir entries */
5965                 num_bytes = 3 * fs_info->nodesize;
5966                 ret = btrfs_qgroup_reserve_meta(root, num_bytes, true);
5967                 if (ret)
5968                         return ret;
5969         } else {
5970                 num_bytes = 0;
5971         }
5972
5973         *qgroup_reserved = num_bytes;
5974
5975         num_bytes = btrfs_calc_trans_metadata_size(fs_info, items);
5976         rsv->space_info = __find_space_info(fs_info,
5977                                             BTRFS_BLOCK_GROUP_METADATA);
5978         ret = btrfs_block_rsv_add(root, rsv, num_bytes,
5979                                   BTRFS_RESERVE_FLUSH_ALL);
5980
5981         if (ret == -ENOSPC && use_global_rsv)
5982                 ret = btrfs_block_rsv_migrate(global_rsv, rsv, num_bytes, 1);
5983
5984         if (ret && *qgroup_reserved)
5985                 btrfs_qgroup_free_meta(root, *qgroup_reserved);
5986
5987         return ret;
5988 }
5989
5990 void btrfs_subvolume_release_metadata(struct btrfs_fs_info *fs_info,
5991                                       struct btrfs_block_rsv *rsv)
5992 {
5993         btrfs_block_rsv_release(fs_info, rsv, (u64)-1);
5994 }
5995
5996 /**
5997  * drop_outstanding_extent - drop an outstanding extent
5998  * @inode: the inode we're dropping the extent for
5999  * @num_bytes: the number of bytes we're releasing.
6000  *
6001  * This is called when we are freeing up an outstanding extent, either called
6002  * after an error or after an extent is written.  This will return the number of
6003  * reserved extents that need to be freed.  This must be called with
6004  * BTRFS_I(inode)->lock held.
6005  */
6006 static unsigned drop_outstanding_extent(struct btrfs_inode *inode,
6007                 u64 num_bytes)
6008 {
6009         unsigned drop_inode_space = 0;
6010         unsigned dropped_extents = 0;
6011         unsigned num_extents;
6012
6013         num_extents = count_max_extents(num_bytes);
6014         ASSERT(num_extents);
6015         ASSERT(inode->outstanding_extents >= num_extents);
6016         inode->outstanding_extents -= num_extents;
6017
6018         if (inode->outstanding_extents == 0 &&
6019             test_and_clear_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
6020                                &inode->runtime_flags))
6021                 drop_inode_space = 1;
6022
6023         /*
6024          * If we have more or the same amount of outstanding extents than we have
6025          * reserved then we need to leave the reserved extents count alone.
6026          */
6027         if (inode->outstanding_extents >= inode->reserved_extents)
6028                 return drop_inode_space;
6029
6030         dropped_extents = inode->reserved_extents - inode->outstanding_extents;
6031         inode->reserved_extents -= dropped_extents;
6032         return dropped_extents + drop_inode_space;
6033 }
6034
6035 /**
6036  * calc_csum_metadata_size - return the amount of metadata space that must be
6037  *      reserved/freed for the given bytes.
6038  * @inode: the inode we're manipulating
6039  * @num_bytes: the number of bytes in question
6040  * @reserve: 1 if we are reserving space, 0 if we are freeing space
6041  *
6042  * This adjusts the number of csum_bytes in the inode and then returns the
6043  * correct amount of metadata that must either be reserved or freed.  We
6044  * calculate how many checksums we can fit into one leaf and then divide the
6045  * number of bytes that will need to be checksumed by this value to figure out
6046  * how many checksums will be required.  If we are adding bytes then the number
6047  * may go up and we will return the number of additional bytes that must be
6048  * reserved.  If it is going down we will return the number of bytes that must
6049  * be freed.
6050  *
6051  * This must be called with BTRFS_I(inode)->lock held.
6052  */
6053 static u64 calc_csum_metadata_size(struct btrfs_inode *inode, u64 num_bytes,
6054                                    int reserve)
6055 {
6056         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6057         u64 old_csums, num_csums;
6058
6059         if (inode->flags & BTRFS_INODE_NODATASUM && inode->csum_bytes == 0)
6060                 return 0;
6061
6062         old_csums = btrfs_csum_bytes_to_leaves(fs_info, inode->csum_bytes);
6063         if (reserve)
6064                 inode->csum_bytes += num_bytes;
6065         else
6066                 inode->csum_bytes -= num_bytes;
6067         num_csums = btrfs_csum_bytes_to_leaves(fs_info, inode->csum_bytes);
6068
6069         /* No change, no need to reserve more */
6070         if (old_csums == num_csums)
6071                 return 0;
6072
6073         if (reserve)
6074                 return btrfs_calc_trans_metadata_size(fs_info,
6075                                                       num_csums - old_csums);
6076
6077         return btrfs_calc_trans_metadata_size(fs_info, old_csums - num_csums);
6078 }
6079
6080 int btrfs_delalloc_reserve_metadata(struct btrfs_inode *inode, u64 num_bytes)
6081 {
6082         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6083         struct btrfs_root *root = inode->root;
6084         struct btrfs_block_rsv *block_rsv = &fs_info->delalloc_block_rsv;
6085         u64 to_reserve = 0;
6086         u64 csum_bytes;
6087         unsigned nr_extents;
6088         enum btrfs_reserve_flush_enum flush = BTRFS_RESERVE_FLUSH_ALL;
6089         int ret = 0;
6090         bool delalloc_lock = true;
6091         u64 to_free = 0;
6092         unsigned dropped;
6093         bool release_extra = false;
6094
6095         /* If we are a free space inode we need to not flush since we will be in
6096          * the middle of a transaction commit.  We also don't need the delalloc
6097          * mutex since we won't race with anybody.  We need this mostly to make
6098          * lockdep shut its filthy mouth.
6099          *
6100          * If we have a transaction open (can happen if we call truncate_block
6101          * from truncate), then we need FLUSH_LIMIT so we don't deadlock.
6102          */
6103         if (btrfs_is_free_space_inode(inode)) {
6104                 flush = BTRFS_RESERVE_NO_FLUSH;
6105                 delalloc_lock = false;
6106         } else if (current->journal_info) {
6107                 flush = BTRFS_RESERVE_FLUSH_LIMIT;
6108         }
6109
6110         if (flush != BTRFS_RESERVE_NO_FLUSH &&
6111             btrfs_transaction_in_commit(fs_info))
6112                 schedule_timeout(1);
6113
6114         if (delalloc_lock)
6115                 mutex_lock(&inode->delalloc_mutex);
6116
6117         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
6118
6119         spin_lock(&inode->lock);
6120         nr_extents = count_max_extents(num_bytes);
6121         inode->outstanding_extents += nr_extents;
6122
6123         nr_extents = 0;
6124         if (inode->outstanding_extents > inode->reserved_extents)
6125                 nr_extents += inode->outstanding_extents -
6126                         inode->reserved_extents;
6127
6128         /* We always want to reserve a slot for updating the inode. */
6129         to_reserve = btrfs_calc_trans_metadata_size(fs_info, nr_extents + 1);
6130         to_reserve += calc_csum_metadata_size(inode, num_bytes, 1);
6131         csum_bytes = inode->csum_bytes;
6132         spin_unlock(&inode->lock);
6133
6134         if (test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
6135                 ret = btrfs_qgroup_reserve_meta(root,
6136                                 nr_extents * fs_info->nodesize, true);
6137                 if (ret)
6138                         goto out_fail;
6139         }
6140
6141         ret = btrfs_block_rsv_add(root, block_rsv, to_reserve, flush);
6142         if (unlikely(ret)) {
6143                 btrfs_qgroup_free_meta(root,
6144                                        nr_extents * fs_info->nodesize);
6145                 goto out_fail;
6146         }
6147
6148         spin_lock(&inode->lock);
6149         if (test_and_set_bit(BTRFS_INODE_DELALLOC_META_RESERVED,
6150                              &inode->runtime_flags)) {
6151                 to_reserve -= btrfs_calc_trans_metadata_size(fs_info, 1);
6152                 release_extra = true;
6153         }
6154         inode->reserved_extents += nr_extents;
6155         spin_unlock(&inode->lock);
6156
6157         if (delalloc_lock)
6158                 mutex_unlock(&inode->delalloc_mutex);
6159
6160         if (to_reserve)
6161                 trace_btrfs_space_reservation(fs_info, "delalloc",
6162                                               btrfs_ino(inode), to_reserve, 1);
6163         if (release_extra)
6164                 btrfs_block_rsv_release(fs_info, block_rsv,
6165                                 btrfs_calc_trans_metadata_size(fs_info, 1));
6166         return 0;
6167
6168 out_fail:
6169         spin_lock(&inode->lock);
6170         dropped = drop_outstanding_extent(inode, num_bytes);
6171         /*
6172          * If the inodes csum_bytes is the same as the original
6173          * csum_bytes then we know we haven't raced with any free()ers
6174          * so we can just reduce our inodes csum bytes and carry on.
6175          */
6176         if (inode->csum_bytes == csum_bytes) {
6177                 calc_csum_metadata_size(inode, num_bytes, 0);
6178         } else {
6179                 u64 orig_csum_bytes = inode->csum_bytes;
6180                 u64 bytes;
6181
6182                 /*
6183                  * This is tricky, but first we need to figure out how much we
6184                  * freed from any free-ers that occurred during this
6185                  * reservation, so we reset ->csum_bytes to the csum_bytes
6186                  * before we dropped our lock, and then call the free for the
6187                  * number of bytes that were freed while we were trying our
6188                  * reservation.
6189                  */
6190                 bytes = csum_bytes - inode->csum_bytes;
6191                 inode->csum_bytes = csum_bytes;
6192                 to_free = calc_csum_metadata_size(inode, bytes, 0);
6193
6194
6195                 /*
6196                  * Now we need to see how much we would have freed had we not
6197                  * been making this reservation and our ->csum_bytes were not
6198                  * artificially inflated.
6199                  */
6200                 inode->csum_bytes = csum_bytes - num_bytes;
6201                 bytes = csum_bytes - orig_csum_bytes;
6202                 bytes = calc_csum_metadata_size(inode, bytes, 0);
6203
6204                 /*
6205                  * Now reset ->csum_bytes to what it should be.  If bytes is
6206                  * more than to_free then we would have freed more space had we
6207                  * not had an artificially high ->csum_bytes, so we need to free
6208                  * the remainder.  If bytes is the same or less then we don't
6209                  * need to do anything, the other free-ers did the correct
6210                  * thing.
6211                  */
6212                 inode->csum_bytes = orig_csum_bytes - num_bytes;
6213                 if (bytes > to_free)
6214                         to_free = bytes - to_free;
6215                 else
6216                         to_free = 0;
6217         }
6218         spin_unlock(&inode->lock);
6219         if (dropped)
6220                 to_free += btrfs_calc_trans_metadata_size(fs_info, dropped);
6221
6222         if (to_free) {
6223                 btrfs_block_rsv_release(fs_info, block_rsv, to_free);
6224                 trace_btrfs_space_reservation(fs_info, "delalloc",
6225                                               btrfs_ino(inode), to_free, 0);
6226         }
6227         if (delalloc_lock)
6228                 mutex_unlock(&inode->delalloc_mutex);
6229         return ret;
6230 }
6231
6232 /**
6233  * btrfs_delalloc_release_metadata - release a metadata reservation for an inode
6234  * @inode: the inode to release the reservation for
6235  * @num_bytes: the number of bytes we're releasing
6236  *
6237  * This will release the metadata reservation for an inode.  This can be called
6238  * once we complete IO for a given set of bytes to release their metadata
6239  * reservations.
6240  */
6241 void btrfs_delalloc_release_metadata(struct btrfs_inode *inode, u64 num_bytes)
6242 {
6243         struct btrfs_fs_info *fs_info = btrfs_sb(inode->vfs_inode.i_sb);
6244         u64 to_free = 0;
6245         unsigned dropped;
6246
6247         num_bytes = ALIGN(num_bytes, fs_info->sectorsize);
6248         spin_lock(&inode->lock);
6249         dropped = drop_outstanding_extent(inode, num_bytes);
6250
6251         if (num_bytes)
6252                 to_free = calc_csum_metadata_size(inode, num_bytes, 0);
6253         spin_unlock(&inode->lock);
6254         if (dropped > 0)
6255                 to_free += btrfs_calc_trans_metadata_size(fs_info, dropped);
6256
6257         if (btrfs_is_testing(fs_info))
6258                 return;
6259
6260         trace_btrfs_space_reservation(fs_info, "delalloc", btrfs_ino(inode),
6261                                       to_free, 0);
6262
6263         btrfs_block_rsv_release(fs_info, &fs_info->delalloc_block_rsv, to_free);
6264 }
6265
6266 /**
6267  * btrfs_delalloc_reserve_space - reserve data and metadata space for
6268  * delalloc
6269  * @inode: inode we're writing to
6270  * @start: start range we are writing to
6271  * @len: how long the range we are writing to
6272  * @reserved: mandatory parameter, record actually reserved qgroup ranges of
6273  *            current reservation.
6274  *
6275  * This will do the following things
6276  *
6277  * o reserve space in data space info for num bytes
6278  *   and reserve precious corresponding qgroup space
6279  *   (Done in check_data_free_space)
6280  *
6281  * o reserve space for metadata space, based on the number of outstanding
6282  *   extents and how much csums will be needed
6283  *   also reserve metadata space in a per root over-reserve method.
6284  * o add to the inodes->delalloc_bytes
6285  * o add it to the fs_info's delalloc inodes list.
6286  *   (Above 3 all done in delalloc_reserve_metadata)
6287  *
6288  * Return 0 for success
6289  * Return <0 for error(-ENOSPC or -EQUOT)
6290  */
6291 int btrfs_delalloc_reserve_space(struct inode *inode,
6292                         struct extent_changeset **reserved, u64 start, u64 len)
6293 {
6294         int ret;
6295
6296         ret = btrfs_check_data_free_space(inode, reserved, start, len);
6297         if (ret < 0)
6298                 return ret;
6299         ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode), len);
6300         if (ret < 0)
6301                 btrfs_free_reserved_data_space(inode, *reserved, start, len);
6302         return ret;
6303 }
6304
6305 /**
6306  * btrfs_delalloc_release_space - release data and metadata space for delalloc
6307  * @inode: inode we're releasing space for
6308  * @start: start position of the space already reserved
6309  * @len: the len of the space already reserved
6310  *
6311  * This must be matched with a call to btrfs_delalloc_reserve_space.  This is
6312  * called in the case that we don't need the metadata AND data reservations
6313  * anymore.  So if there is an error or we insert an inline extent.
6314  *
6315  * This function will release the metadata space that was not used and will
6316  * decrement ->delalloc_bytes and remove it from the fs_info delalloc_inodes
6317  * list if there are no delalloc bytes left.
6318  * Also it will handle the qgroup reserved space.
6319  */
6320 void btrfs_delalloc_release_space(struct inode *inode,
6321                         struct extent_changeset *reserved, u64 start, u64 len)
6322 {
6323         btrfs_delalloc_release_metadata(BTRFS_I(inode), len);
6324         btrfs_free_reserved_data_space(inode, reserved, start, len);
6325 }
6326
6327 static int update_block_group(struct btrfs_trans_handle *trans,
6328                               struct btrfs_fs_info *info, u64 bytenr,
6329                               u64 num_bytes, int alloc)
6330 {
6331         struct btrfs_block_group_cache *cache = NULL;
6332         u64 total = num_bytes;
6333         u64 old_val;
6334         u64 byte_in_group;
6335         int factor;
6336
6337         /* block accounting for super block */
6338         spin_lock(&info->delalloc_root_lock);
6339         old_val = btrfs_super_bytes_used(info->super_copy);
6340         if (alloc)
6341                 old_val += num_bytes;
6342         else
6343                 old_val -= num_bytes;
6344         btrfs_set_super_bytes_used(info->super_copy, old_val);
6345         spin_unlock(&info->delalloc_root_lock);
6346
6347         while (total) {
6348                 cache = btrfs_lookup_block_group(info, bytenr);
6349                 if (!cache)
6350                         return -ENOENT;
6351                 if (cache->flags & (BTRFS_BLOCK_GROUP_DUP |
6352                                     BTRFS_BLOCK_GROUP_RAID1 |
6353                                     BTRFS_BLOCK_GROUP_RAID10))
6354                         factor = 2;
6355                 else
6356                         factor = 1;
6357                 /*
6358                  * If this block group has free space cache written out, we
6359                  * need to make sure to load it if we are removing space.  This
6360                  * is because we need the unpinning stage to actually add the
6361                  * space back to the block group, otherwise we will leak space.
6362                  */
6363                 if (!alloc && cache->cached == BTRFS_CACHE_NO)
6364                         cache_block_group(cache, 1);
6365
6366                 byte_in_group = bytenr - cache->key.objectid;
6367                 WARN_ON(byte_in_group > cache->key.offset);
6368
6369                 spin_lock(&cache->space_info->lock);
6370                 spin_lock(&cache->lock);
6371
6372                 if (btrfs_test_opt(info, SPACE_CACHE) &&
6373                     cache->disk_cache_state < BTRFS_DC_CLEAR)
6374                         cache->disk_cache_state = BTRFS_DC_CLEAR;
6375
6376                 old_val = btrfs_block_group_used(&cache->item);
6377                 num_bytes = min(total, cache->key.offset - byte_in_group);
6378                 if (alloc) {
6379                         old_val += num_bytes;
6380                         btrfs_set_block_group_used(&cache->item, old_val);
6381                         cache->reserved -= num_bytes;
6382                         cache->space_info->bytes_reserved -= num_bytes;
6383                         cache->space_info->bytes_used += num_bytes;
6384                         cache->space_info->disk_used += num_bytes * factor;
6385                         spin_unlock(&cache->lock);
6386                         spin_unlock(&cache->space_info->lock);
6387                 } else {
6388                         old_val -= num_bytes;
6389                         btrfs_set_block_group_used(&cache->item, old_val);
6390                         cache->pinned += num_bytes;
6391                         cache->space_info->bytes_pinned += num_bytes;
6392                         cache->space_info->bytes_used -= num_bytes;
6393                         cache->space_info->disk_used -= num_bytes * factor;
6394                         spin_unlock(&cache->lock);
6395                         spin_unlock(&cache->space_info->lock);
6396
6397                         trace_btrfs_space_reservation(info, "pinned",
6398                                                       cache->space_info->flags,
6399                                                       num_bytes, 1);
6400                         percpu_counter_add(&cache->space_info->total_bytes_pinned,
6401                                            num_bytes);
6402                         set_extent_dirty(info->pinned_extents,
6403                                          bytenr, bytenr + num_bytes - 1,
6404                                          GFP_NOFS | __GFP_NOFAIL);
6405                 }
6406
6407                 spin_lock(&trans->transaction->dirty_bgs_lock);
6408                 if (list_empty(&cache->dirty_list)) {
6409                         list_add_tail(&cache->dirty_list,
6410                                       &trans->transaction->dirty_bgs);
6411                                 trans->transaction->num_dirty_bgs++;
6412                         btrfs_get_block_group(cache);
6413                 }
6414                 spin_unlock(&trans->transaction->dirty_bgs_lock);
6415
6416                 /*
6417                  * No longer have used bytes in this block group, queue it for
6418                  * deletion. We do this after adding the block group to the
6419                  * dirty list to avoid races between cleaner kthread and space
6420                  * cache writeout.
6421                  */
6422                 if (!alloc && old_val == 0) {
6423                         spin_lock(&info->unused_bgs_lock);
6424                         if (list_empty(&cache->bg_list)) {
6425                                 btrfs_get_block_group(cache);
6426                                 list_add_tail(&cache->bg_list,
6427                                               &info->unused_bgs);
6428                         }
6429                         spin_unlock(&info->unused_bgs_lock);
6430                 }
6431
6432                 btrfs_put_block_group(cache);
6433                 total -= num_bytes;
6434                 bytenr += num_bytes;
6435         }
6436         return 0;
6437 }
6438
6439 static u64 first_logical_byte(struct btrfs_fs_info *fs_info, u64 search_start)
6440 {
6441         struct btrfs_block_group_cache *cache;
6442         u64 bytenr;
6443
6444         spin_lock(&fs_info->block_group_cache_lock);
6445         bytenr = fs_info->first_logical_byte;
6446         spin_unlock(&fs_info->block_group_cache_lock);
6447
6448         if (bytenr < (u64)-1)
6449                 return bytenr;
6450
6451         cache = btrfs_lookup_first_block_group(fs_info, search_start);
6452         if (!cache)
6453                 return 0;
6454
6455         bytenr = cache->key.objectid;
6456         btrfs_put_block_group(cache);
6457
6458         return bytenr;
6459 }
6460
6461 static int pin_down_extent(struct btrfs_fs_info *fs_info,
6462                            struct btrfs_block_group_cache *cache,
6463                            u64 bytenr, u64 num_bytes, int reserved)
6464 {
6465         spin_lock(&cache->space_info->lock);
6466         spin_lock(&cache->lock);
6467         cache->pinned += num_bytes;
6468         cache->space_info->bytes_pinned += num_bytes;
6469         if (reserved) {
6470                 cache->reserved -= num_bytes;
6471                 cache->space_info->bytes_reserved -= num_bytes;
6472         }
6473         spin_unlock(&cache->lock);
6474         spin_unlock(&cache->space_info->lock);
6475
6476         trace_btrfs_space_reservation(fs_info, "pinned",
6477                                       cache->space_info->flags, num_bytes, 1);
6478         percpu_counter_add(&cache->space_info->total_bytes_pinned, num_bytes);
6479         set_extent_dirty(fs_info->pinned_extents, bytenr,
6480                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
6481         return 0;
6482 }
6483
6484 /*
6485  * this function must be called within transaction
6486  */
6487 int btrfs_pin_extent(struct btrfs_fs_info *fs_info,
6488                      u64 bytenr, u64 num_bytes, int reserved)
6489 {
6490         struct btrfs_block_group_cache *cache;
6491
6492         cache = btrfs_lookup_block_group(fs_info, bytenr);
6493         BUG_ON(!cache); /* Logic error */
6494
6495         pin_down_extent(fs_info, cache, bytenr, num_bytes, reserved);
6496
6497         btrfs_put_block_group(cache);
6498         return 0;
6499 }
6500
6501 /*
6502  * this function must be called within transaction
6503  */
6504 int btrfs_pin_extent_for_log_replay(struct btrfs_fs_info *fs_info,
6505                                     u64 bytenr, u64 num_bytes)
6506 {
6507         struct btrfs_block_group_cache *cache;
6508         int ret;
6509
6510         cache = btrfs_lookup_block_group(fs_info, bytenr);
6511         if (!cache)
6512                 return -EINVAL;
6513
6514         /*
6515          * pull in the free space cache (if any) so that our pin
6516          * removes the free space from the cache.  We have load_only set
6517          * to one because the slow code to read in the free extents does check
6518          * the pinned extents.
6519          */
6520         cache_block_group(cache, 1);
6521
6522         pin_down_extent(fs_info, cache, bytenr, num_bytes, 0);
6523
6524         /* remove us from the free space cache (if we're there at all) */
6525         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
6526         btrfs_put_block_group(cache);
6527         return ret;
6528 }
6529
6530 static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
6531                                    u64 start, u64 num_bytes)
6532 {
6533         int ret;
6534         struct btrfs_block_group_cache *block_group;
6535         struct btrfs_caching_control *caching_ctl;
6536
6537         block_group = btrfs_lookup_block_group(fs_info, start);
6538         if (!block_group)
6539                 return -EINVAL;
6540
6541         cache_block_group(block_group, 0);
6542         caching_ctl = get_caching_control(block_group);
6543
6544         if (!caching_ctl) {
6545                 /* Logic error */
6546                 BUG_ON(!block_group_cache_done(block_group));
6547                 ret = btrfs_remove_free_space(block_group, start, num_bytes);
6548         } else {
6549                 mutex_lock(&caching_ctl->mutex);
6550
6551                 if (start >= caching_ctl->progress) {
6552                         ret = add_excluded_extent(fs_info, start, num_bytes);
6553                 } else if (start + num_bytes <= caching_ctl->progress) {
6554                         ret = btrfs_remove_free_space(block_group,
6555                                                       start, num_bytes);
6556                 } else {
6557                         num_bytes = caching_ctl->progress - start;
6558                         ret = btrfs_remove_free_space(block_group,
6559                                                       start, num_bytes);
6560                         if (ret)
6561                                 goto out_lock;
6562
6563                         num_bytes = (start + num_bytes) -
6564                                 caching_ctl->progress;
6565                         start = caching_ctl->progress;
6566                         ret = add_excluded_extent(fs_info, start, num_bytes);
6567                 }
6568 out_lock:
6569                 mutex_unlock(&caching_ctl->mutex);
6570                 put_caching_control(caching_ctl);
6571         }
6572         btrfs_put_block_group(block_group);
6573         return ret;
6574 }
6575
6576 int btrfs_exclude_logged_extents(struct btrfs_fs_info *fs_info,
6577                                  struct extent_buffer *eb)
6578 {
6579         struct btrfs_file_extent_item *item;
6580         struct btrfs_key key;
6581         int found_type;
6582         int i;
6583
6584         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
6585                 return 0;
6586
6587         for (i = 0; i < btrfs_header_nritems(eb); i++) {
6588                 btrfs_item_key_to_cpu(eb, &key, i);
6589                 if (key.type != BTRFS_EXTENT_DATA_KEY)
6590                         continue;
6591                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
6592                 found_type = btrfs_file_extent_type(eb, item);
6593                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
6594                         continue;
6595                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
6596                         continue;
6597                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
6598                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
6599                 __exclude_logged_extent(fs_info, key.objectid, key.offset);
6600         }
6601
6602         return 0;
6603 }
6604
6605 static void
6606 btrfs_inc_block_group_reservations(struct btrfs_block_group_cache *bg)
6607 {
6608         atomic_inc(&bg->reservations);
6609 }
6610
6611 void btrfs_dec_block_group_reservations(struct btrfs_fs_info *fs_info,
6612                                         const u64 start)
6613 {
6614         struct btrfs_block_group_cache *bg;
6615
6616         bg = btrfs_lookup_block_group(fs_info, start);
6617         ASSERT(bg);
6618         if (atomic_dec_and_test(&bg->reservations))
6619                 wake_up_atomic_t(&bg->reservations);
6620         btrfs_put_block_group(bg);
6621 }
6622
6623 static int btrfs_wait_bg_reservations_atomic_t(atomic_t *a)
6624 {
6625         schedule();
6626         return 0;
6627 }
6628
6629 void btrfs_wait_block_group_reservations(struct btrfs_block_group_cache *bg)
6630 {
6631         struct btrfs_space_info *space_info = bg->space_info;
6632
6633         ASSERT(bg->ro);
6634
6635         if (!(bg->flags & BTRFS_BLOCK_GROUP_DATA))
6636                 return;
6637
6638         /*
6639          * Our block group is read only but before we set it to read only,
6640          * some task might have had allocated an extent from it already, but it
6641          * has not yet created a respective ordered extent (and added it to a
6642          * root's list of ordered extents).
6643          * Therefore wait for any task currently allocating extents, since the
6644          * block group's reservations counter is incremented while a read lock
6645          * on the groups' semaphore is held and decremented after releasing
6646          * the read access on that semaphore and creating the ordered extent.
6647          */
6648         down_write(&space_info->groups_sem);
6649         up_write(&space_info->groups_sem);
6650
6651         wait_on_atomic_t(&bg->reservations,
6652                          btrfs_wait_bg_reservations_atomic_t,
6653                          TASK_UNINTERRUPTIBLE);
6654 }
6655
6656 /**
6657  * btrfs_add_reserved_bytes - update the block_group and space info counters
6658  * @cache:      The cache we are manipulating
6659  * @ram_bytes:  The number of bytes of file content, and will be same to
6660  *              @num_bytes except for the compress path.
6661  * @num_bytes:  The number of bytes in question
6662  * @delalloc:   The blocks are allocated for the delalloc write
6663  *
6664  * This is called by the allocator when it reserves space. If this is a
6665  * reservation and the block group has become read only we cannot make the
6666  * reservation and return -EAGAIN, otherwise this function always succeeds.
6667  */
6668 static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache,
6669                                     u64 ram_bytes, u64 num_bytes, int delalloc)
6670 {
6671         struct btrfs_space_info *space_info = cache->space_info;
6672         int ret = 0;
6673
6674         spin_lock(&space_info->lock);
6675         spin_lock(&cache->lock);
6676         if (cache->ro) {
6677                 ret = -EAGAIN;
6678         } else {
6679                 cache->reserved += num_bytes;
6680                 space_info->bytes_reserved += num_bytes;
6681
6682                 trace_btrfs_space_reservation(cache->fs_info,
6683                                 "space_info", space_info->flags,
6684                                 ram_bytes, 0);
6685                 space_info->bytes_may_use -= ram_bytes;
6686                 if (delalloc)
6687                         cache->delalloc_bytes += num_bytes;
6688         }
6689         spin_unlock(&cache->lock);
6690         spin_unlock(&space_info->lock);
6691         return ret;
6692 }
6693
6694 /**
6695  * btrfs_free_reserved_bytes - update the block_group and space info counters
6696  * @cache:      The cache we are manipulating
6697  * @num_bytes:  The number of bytes in question
6698  * @delalloc:   The blocks are allocated for the delalloc write
6699  *
6700  * This is called by somebody who is freeing space that was never actually used
6701  * on disk.  For example if you reserve some space for a new leaf in transaction
6702  * A and before transaction A commits you free that leaf, you call this with
6703  * reserve set to 0 in order to clear the reservation.
6704  */
6705
6706 static int btrfs_free_reserved_bytes(struct btrfs_block_group_cache *cache,
6707                                      u64 num_bytes, int delalloc)
6708 {
6709         struct btrfs_space_info *space_info = cache->space_info;
6710         int ret = 0;
6711
6712         spin_lock(&space_info->lock);
6713         spin_lock(&cache->lock);
6714         if (cache->ro)
6715                 space_info->bytes_readonly += num_bytes;
6716         cache->reserved -= num_bytes;
6717         space_info->bytes_reserved -= num_bytes;
6718
6719         if (delalloc)
6720                 cache->delalloc_bytes -= num_bytes;
6721         spin_unlock(&cache->lock);
6722         spin_unlock(&space_info->lock);
6723         return ret;
6724 }
6725 void btrfs_prepare_extent_commit(struct btrfs_fs_info *fs_info)
6726 {
6727         struct btrfs_caching_control *next;
6728         struct btrfs_caching_control *caching_ctl;
6729         struct btrfs_block_group_cache *cache;
6730
6731         down_write(&fs_info->commit_root_sem);
6732
6733         list_for_each_entry_safe(caching_ctl, next,
6734                                  &fs_info->caching_block_groups, list) {
6735                 cache = caching_ctl->block_group;
6736                 if (block_group_cache_done(cache)) {
6737                         cache->last_byte_to_unpin = (u64)-1;
6738                         list_del_init(&caching_ctl->list);
6739                         put_caching_control(caching_ctl);
6740                 } else {
6741                         cache->last_byte_to_unpin = caching_ctl->progress;
6742                 }
6743         }
6744
6745         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6746                 fs_info->pinned_extents = &fs_info->freed_extents[1];
6747         else
6748                 fs_info->pinned_extents = &fs_info->freed_extents[0];
6749
6750         up_write(&fs_info->commit_root_sem);
6751
6752         update_global_block_rsv(fs_info);
6753 }
6754
6755 /*
6756  * Returns the free cluster for the given space info and sets empty_cluster to
6757  * what it should be based on the mount options.
6758  */
6759 static struct btrfs_free_cluster *
6760 fetch_cluster_info(struct btrfs_fs_info *fs_info,
6761                    struct btrfs_space_info *space_info, u64 *empty_cluster)
6762 {
6763         struct btrfs_free_cluster *ret = NULL;
6764
6765         *empty_cluster = 0;
6766         if (btrfs_mixed_space_info(space_info))
6767                 return ret;
6768
6769         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
6770                 ret = &fs_info->meta_alloc_cluster;
6771                 if (btrfs_test_opt(fs_info, SSD))
6772                         *empty_cluster = SZ_2M;
6773                 else
6774                         *empty_cluster = SZ_64K;
6775         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
6776                    btrfs_test_opt(fs_info, SSD_SPREAD)) {
6777                 *empty_cluster = SZ_2M;
6778                 ret = &fs_info->data_alloc_cluster;
6779         }
6780
6781         return ret;
6782 }
6783
6784 static int unpin_extent_range(struct btrfs_fs_info *fs_info,
6785                               u64 start, u64 end,
6786                               const bool return_free_space)
6787 {
6788         struct btrfs_block_group_cache *cache = NULL;
6789         struct btrfs_space_info *space_info;
6790         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
6791         struct btrfs_free_cluster *cluster = NULL;
6792         u64 len;
6793         u64 total_unpinned = 0;
6794         u64 empty_cluster = 0;
6795         bool readonly;
6796
6797         while (start <= end) {
6798                 readonly = false;
6799                 if (!cache ||
6800                     start >= cache->key.objectid + cache->key.offset) {
6801                         if (cache)
6802                                 btrfs_put_block_group(cache);
6803                         total_unpinned = 0;
6804                         cache = btrfs_lookup_block_group(fs_info, start);
6805                         BUG_ON(!cache); /* Logic error */
6806
6807                         cluster = fetch_cluster_info(fs_info,
6808                                                      cache->space_info,
6809                                                      &empty_cluster);
6810                         empty_cluster <<= 1;
6811                 }
6812
6813                 len = cache->key.objectid + cache->key.offset - start;
6814                 len = min(len, end + 1 - start);
6815
6816                 if (start < cache->last_byte_to_unpin) {
6817                         len = min(len, cache->last_byte_to_unpin - start);
6818                         if (return_free_space)
6819                                 btrfs_add_free_space(cache, start, len);
6820                 }
6821
6822                 start += len;
6823                 total_unpinned += len;
6824                 space_info = cache->space_info;
6825
6826                 /*
6827                  * If this space cluster has been marked as fragmented and we've
6828                  * unpinned enough in this block group to potentially allow a
6829                  * cluster to be created inside of it go ahead and clear the
6830                  * fragmented check.
6831                  */
6832                 if (cluster && cluster->fragmented &&
6833                     total_unpinned > empty_cluster) {
6834                         spin_lock(&cluster->lock);
6835                         cluster->fragmented = 0;
6836                         spin_unlock(&cluster->lock);
6837                 }
6838
6839                 spin_lock(&space_info->lock);
6840                 spin_lock(&cache->lock);
6841                 cache->pinned -= len;
6842                 space_info->bytes_pinned -= len;
6843
6844                 trace_btrfs_space_reservation(fs_info, "pinned",
6845                                               space_info->flags, len, 0);
6846                 space_info->max_extent_size = 0;
6847                 percpu_counter_add(&space_info->total_bytes_pinned, -len);
6848                 if (cache->ro) {
6849                         space_info->bytes_readonly += len;
6850                         readonly = true;
6851                 }
6852                 spin_unlock(&cache->lock);
6853                 if (!readonly && return_free_space &&
6854                     global_rsv->space_info == space_info) {
6855                         u64 to_add = len;
6856
6857                         spin_lock(&global_rsv->lock);
6858                         if (!global_rsv->full) {
6859                                 to_add = min(len, global_rsv->size -
6860                                              global_rsv->reserved);
6861                                 global_rsv->reserved += to_add;
6862                                 space_info->bytes_may_use += to_add;
6863                                 if (global_rsv->reserved >= global_rsv->size)
6864                                         global_rsv->full = 1;
6865                                 trace_btrfs_space_reservation(fs_info,
6866                                                               "space_info",
6867                                                               space_info->flags,
6868                                                               to_add, 1);
6869                                 len -= to_add;
6870                         }
6871                         spin_unlock(&global_rsv->lock);
6872                         /* Add to any tickets we may have */
6873                         if (len)
6874                                 space_info_add_new_bytes(fs_info, space_info,
6875                                                          len);
6876                 }
6877                 spin_unlock(&space_info->lock);
6878         }
6879
6880         if (cache)
6881                 btrfs_put_block_group(cache);
6882         return 0;
6883 }
6884
6885 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
6886                                struct btrfs_fs_info *fs_info)
6887 {
6888         struct btrfs_block_group_cache *block_group, *tmp;
6889         struct list_head *deleted_bgs;
6890         struct extent_io_tree *unpin;
6891         u64 start;
6892         u64 end;
6893         int ret;
6894
6895         if (fs_info->pinned_extents == &fs_info->freed_extents[0])
6896                 unpin = &fs_info->freed_extents[1];
6897         else
6898                 unpin = &fs_info->freed_extents[0];
6899
6900         while (!trans->aborted) {
6901                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
6902                 ret = find_first_extent_bit(unpin, 0, &start, &end,
6903                                             EXTENT_DIRTY, NULL);
6904                 if (ret) {
6905                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6906                         break;
6907                 }
6908
6909                 if (btrfs_test_opt(fs_info, DISCARD))
6910                         ret = btrfs_discard_extent(fs_info, start,
6911                                                    end + 1 - start, NULL);
6912
6913                 clear_extent_dirty(unpin, start, end);
6914                 unpin_extent_range(fs_info, start, end, true);
6915                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
6916                 cond_resched();
6917         }
6918
6919         /*
6920          * Transaction is finished.  We don't need the lock anymore.  We
6921          * do need to clean up the block groups in case of a transaction
6922          * abort.
6923          */
6924         deleted_bgs = &trans->transaction->deleted_bgs;
6925         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
6926                 u64 trimmed = 0;
6927
6928                 ret = -EROFS;
6929                 if (!trans->aborted)
6930                         ret = btrfs_discard_extent(fs_info,
6931                                                    block_group->key.objectid,
6932                                                    block_group->key.offset,
6933                                                    &trimmed);
6934
6935                 list_del_init(&block_group->bg_list);
6936                 btrfs_put_block_group_trimming(block_group);
6937                 btrfs_put_block_group(block_group);
6938
6939                 if (ret) {
6940                         const char *errstr = btrfs_decode_error(ret);
6941                         btrfs_warn(fs_info,
6942                            "discard failed while removing blockgroup: errno=%d %s",
6943                                    ret, errstr);
6944                 }
6945         }
6946
6947         return 0;
6948 }
6949
6950 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
6951                                 struct btrfs_fs_info *info,
6952                                 struct btrfs_delayed_ref_node *node, u64 parent,
6953                                 u64 root_objectid, u64 owner_objectid,
6954                                 u64 owner_offset, int refs_to_drop,
6955                                 struct btrfs_delayed_extent_op *extent_op)
6956 {
6957         struct btrfs_key key;
6958         struct btrfs_path *path;
6959         struct btrfs_root *extent_root = info->extent_root;
6960         struct extent_buffer *leaf;
6961         struct btrfs_extent_item *ei;
6962         struct btrfs_extent_inline_ref *iref;
6963         int ret;
6964         int is_data;
6965         int extent_slot = 0;
6966         int found_extent = 0;
6967         int num_to_del = 1;
6968         u32 item_size;
6969         u64 refs;
6970         u64 bytenr = node->bytenr;
6971         u64 num_bytes = node->num_bytes;
6972         int last_ref = 0;
6973         bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
6974
6975         path = btrfs_alloc_path();
6976         if (!path)
6977                 return -ENOMEM;
6978
6979         path->reada = READA_FORWARD;
6980         path->leave_spinning = 1;
6981
6982         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
6983         BUG_ON(!is_data && refs_to_drop != 1);
6984
6985         if (is_data)
6986                 skinny_metadata = 0;
6987
6988         ret = lookup_extent_backref(trans, info, path, &iref,
6989                                     bytenr, num_bytes, parent,
6990                                     root_objectid, owner_objectid,
6991                                     owner_offset);
6992         if (ret == 0) {
6993                 extent_slot = path->slots[0];
6994                 while (extent_slot >= 0) {
6995                         btrfs_item_key_to_cpu(path->nodes[0], &key,
6996                                               extent_slot);
6997                         if (key.objectid != bytenr)
6998                                 break;
6999                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
7000                             key.offset == num_bytes) {
7001                                 found_extent = 1;
7002                                 break;
7003                         }
7004                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
7005                             key.offset == owner_objectid) {
7006                                 found_extent = 1;
7007                                 break;
7008                         }
7009                         if (path->slots[0] - extent_slot > 5)
7010                                 break;
7011                         extent_slot--;
7012                 }
7013 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
7014                 item_size = btrfs_item_size_nr(path->nodes[0], extent_slot);
7015                 if (found_extent && item_size < sizeof(*ei))
7016                         found_extent = 0;
7017 #endif
7018                 if (!found_extent) {
7019                         BUG_ON(iref);
7020                         ret = remove_extent_backref(trans, info, path, NULL,
7021                                                     refs_to_drop,
7022                                                     is_data, &last_ref);
7023                         if (ret) {
7024                                 btrfs_abort_transaction(trans, ret);
7025                                 goto out;
7026                         }
7027                         btrfs_release_path(path);
7028                         path->leave_spinning = 1;
7029
7030                         key.objectid = bytenr;
7031                         key.type = BTRFS_EXTENT_ITEM_KEY;
7032                         key.offset = num_bytes;
7033
7034                         if (!is_data && skinny_metadata) {
7035                                 key.type = BTRFS_METADATA_ITEM_KEY;
7036                                 key.offset = owner_objectid;
7037                         }
7038
7039                         ret = btrfs_search_slot(trans, extent_root,
7040                                                 &key, path, -1, 1);
7041                         if (ret > 0 && skinny_metadata && path->slots[0]) {
7042                                 /*
7043                                  * Couldn't find our skinny metadata item,
7044                                  * see if we have ye olde extent item.
7045                                  */
7046                                 path->slots[0]--;
7047                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
7048                                                       path->slots[0]);
7049                                 if (key.objectid == bytenr &&
7050                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
7051                                     key.offset == num_bytes)
7052                                         ret = 0;
7053                         }
7054
7055                         if (ret > 0 && skinny_metadata) {
7056                                 skinny_metadata = false;
7057                                 key.objectid = bytenr;
7058                                 key.type = BTRFS_EXTENT_ITEM_KEY;
7059                                 key.offset = num_bytes;
7060                                 btrfs_release_path(path);
7061                                 ret = btrfs_search_slot(trans, extent_root,
7062                                                         &key, path, -1, 1);
7063                         }
7064
7065                         if (ret) {
7066                                 btrfs_err(info,
7067                                           "umm, got %d back from search, was looking for %llu",
7068                                           ret, bytenr);
7069                                 if (ret > 0)
7070                                         btrfs_print_leaf(path->nodes[0]);
7071                         }
7072                         if (ret < 0) {
7073                                 btrfs_abort_transaction(trans, ret);
7074                                 goto out;
7075                         }
7076                         extent_slot = path->slots[0];
7077                 }
7078         } else if (WARN_ON(ret == -ENOENT)) {
7079                 btrfs_print_leaf(path->nodes[0]);
7080                 btrfs_err(info,
7081                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
7082                         bytenr, parent, root_objectid, owner_objectid,
7083                         owner_offset);
7084                 btrfs_abort_transaction(trans, ret);
7085                 goto out;
7086         } else {
7087                 btrfs_abort_transaction(trans, ret);
7088                 goto out;
7089         }
7090
7091         leaf = path->nodes[0];
7092         item_size = btrfs_item_size_nr(leaf, extent_slot);
7093 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
7094         if (item_size < sizeof(*ei)) {
7095                 BUG_ON(found_extent || extent_slot != path->slots[0]);
7096                 ret = convert_extent_item_v0(trans, info, path, owner_objectid,
7097                                              0);
7098                 if (ret < 0) {
7099                         btrfs_abort_transaction(trans, ret);
7100                         goto out;
7101                 }
7102
7103                 btrfs_release_path(path);
7104                 path->leave_spinning = 1;
7105
7106                 key.objectid = bytenr;
7107                 key.type = BTRFS_EXTENT_ITEM_KEY;
7108                 key.offset = num_bytes;
7109
7110                 ret = btrfs_search_slot(trans, extent_root, &key, path,
7111                                         -1, 1);
7112                 if (ret) {
7113                         btrfs_err(info,
7114                                   "umm, got %d back from search, was looking for %llu",
7115                                 ret, bytenr);
7116                         btrfs_print_leaf(path->nodes[0]);
7117                 }
7118                 if (ret < 0) {
7119                         btrfs_abort_transaction(trans, ret);
7120                         goto out;
7121                 }
7122
7123                 extent_slot = path->slots[0];
7124                 leaf = path->nodes[0];
7125                 item_size = btrfs_item_size_nr(leaf, extent_slot);
7126         }
7127 #endif
7128         BUG_ON(item_size < sizeof(*ei));
7129         ei = btrfs_item_ptr(leaf, extent_slot,
7130                             struct btrfs_extent_item);
7131         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
7132             key.type == BTRFS_EXTENT_ITEM_KEY) {
7133                 struct btrfs_tree_block_info *bi;
7134                 BUG_ON(item_size < sizeof(*ei) + sizeof(*bi));
7135                 bi = (struct btrfs_tree_block_info *)(ei + 1);
7136                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
7137         }
7138
7139         refs = btrfs_extent_refs(leaf, ei);
7140         if (refs < refs_to_drop) {
7141                 btrfs_err(info,
7142                           "trying to drop %d refs but we only have %Lu for bytenr %Lu",
7143                           refs_to_drop, refs, bytenr);
7144                 ret = -EINVAL;
7145                 btrfs_abort_transaction(trans, ret);
7146                 goto out;
7147         }
7148         refs -= refs_to_drop;
7149
7150         if (refs > 0) {
7151                 if (extent_op)
7152                         __run_delayed_extent_op(extent_op, leaf, ei);
7153                 /*
7154                  * In the case of inline back ref, reference count will
7155                  * be updated by remove_extent_backref
7156                  */
7157                 if (iref) {
7158                         BUG_ON(!found_extent);
7159                 } else {
7160                         btrfs_set_extent_refs(leaf, ei, refs);
7161                         btrfs_mark_buffer_dirty(leaf);
7162                 }
7163                 if (found_extent) {
7164                         ret = remove_extent_backref(trans, info, path,
7165                                                     iref, refs_to_drop,
7166                                                     is_data, &last_ref);
7167                         if (ret) {
7168                                 btrfs_abort_transaction(trans, ret);
7169                                 goto out;
7170                         }
7171                 }
7172         } else {
7173                 if (found_extent) {
7174                         BUG_ON(is_data && refs_to_drop !=
7175                                extent_data_ref_count(path, iref));
7176                         if (iref) {
7177                                 BUG_ON(path->slots[0] != extent_slot);
7178                         } else {
7179                                 BUG_ON(path->slots[0] != extent_slot + 1);
7180                                 path->slots[0] = extent_slot;
7181                                 num_to_del = 2;
7182                         }
7183                 }
7184
7185                 last_ref = 1;
7186                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
7187                                       num_to_del);
7188                 if (ret) {
7189                         btrfs_abort_transaction(trans, ret);
7190                         goto out;
7191                 }
7192                 btrfs_release_path(path);
7193
7194                 if (is_data) {
7195                         ret = btrfs_del_csums(trans, info, bytenr, num_bytes);
7196                         if (ret) {
7197                                 btrfs_abort_transaction(trans, ret);
7198                                 goto out;
7199                         }
7200                 }
7201
7202                 ret = add_to_free_space_tree(trans, info, bytenr, num_bytes);
7203                 if (ret) {
7204                         btrfs_abort_transaction(trans, ret);
7205                         goto out;
7206                 }
7207
7208                 ret = update_block_group(trans, info, bytenr, num_bytes, 0);
7209                 if (ret) {
7210                         btrfs_abort_transaction(trans, ret);
7211                         goto out;
7212                 }
7213         }
7214         btrfs_release_path(path);
7215
7216 out:
7217         btrfs_free_path(path);
7218         return ret;
7219 }
7220
7221 /*
7222  * when we free an block, it is possible (and likely) that we free the last
7223  * delayed ref for that extent as well.  This searches the delayed ref tree for
7224  * a given extent, and if there are no other delayed refs to be processed, it
7225  * removes it from the tree.
7226  */
7227 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
7228                                       u64 bytenr)
7229 {
7230         struct btrfs_delayed_ref_head *head;
7231         struct btrfs_delayed_ref_root *delayed_refs;
7232         int ret = 0;
7233
7234         delayed_refs = &trans->transaction->delayed_refs;
7235         spin_lock(&delayed_refs->lock);
7236         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
7237         if (!head)
7238                 goto out_delayed_unlock;
7239
7240         spin_lock(&head->lock);
7241         if (!list_empty(&head->ref_list))
7242                 goto out;
7243
7244         if (head->extent_op) {
7245                 if (!head->must_insert_reserved)
7246                         goto out;
7247                 btrfs_free_delayed_extent_op(head->extent_op);
7248                 head->extent_op = NULL;
7249         }
7250
7251         /*
7252          * waiting for the lock here would deadlock.  If someone else has it
7253          * locked they are already in the process of dropping it anyway
7254          */
7255         if (!mutex_trylock(&head->mutex))
7256                 goto out;
7257
7258         /*
7259          * at this point we have a head with no other entries.  Go
7260          * ahead and process it.
7261          */
7262         head->node.in_tree = 0;
7263         rb_erase(&head->href_node, &delayed_refs->href_root);
7264
7265         atomic_dec(&delayed_refs->num_entries);
7266
7267         /*
7268          * we don't take a ref on the node because we're removing it from the
7269          * tree, so we just steal the ref the tree was holding.
7270          */
7271         delayed_refs->num_heads--;
7272         if (head->processing == 0)
7273                 delayed_refs->num_heads_ready--;
7274         head->processing = 0;
7275         spin_unlock(&head->lock);
7276         spin_unlock(&delayed_refs->lock);
7277
7278         BUG_ON(head->extent_op);
7279         if (head->must_insert_reserved)
7280                 ret = 1;
7281
7282         mutex_unlock(&head->mutex);
7283         btrfs_put_delayed_ref(&head->node);
7284         return ret;
7285 out:
7286         spin_unlock(&head->lock);
7287
7288 out_delayed_unlock:
7289         spin_unlock(&delayed_refs->lock);
7290         return 0;
7291 }
7292
7293 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
7294                            struct btrfs_root *root,
7295                            struct extent_buffer *buf,
7296                            u64 parent, int last_ref)
7297 {
7298         struct btrfs_fs_info *fs_info = root->fs_info;
7299         int pin = 1;
7300         int ret;
7301
7302         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7303                 int old_ref_mod, new_ref_mod;
7304
7305                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, buf->start,
7306                                                  buf->len, parent,
7307                                                  root->root_key.objectid,
7308                                                  btrfs_header_level(buf),
7309                                                  BTRFS_DROP_DELAYED_REF, NULL,
7310                                                  &old_ref_mod, &new_ref_mod);
7311                 BUG_ON(ret); /* -ENOMEM */
7312                 pin = old_ref_mod >= 0 && new_ref_mod < 0;
7313         }
7314
7315         if (last_ref && btrfs_header_generation(buf) == trans->transid) {
7316                 struct btrfs_block_group_cache *cache;
7317
7318                 if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
7319                         ret = check_ref_cleanup(trans, buf->start);
7320                         if (!ret)
7321                                 goto out;
7322                 }
7323
7324                 pin = 0;
7325                 cache = btrfs_lookup_block_group(fs_info, buf->start);
7326
7327                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
7328                         pin_down_extent(fs_info, cache, buf->start,
7329                                         buf->len, 1);
7330                         btrfs_put_block_group(cache);
7331                         goto out;
7332                 }
7333
7334                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
7335
7336                 btrfs_add_free_space(cache, buf->start, buf->len);
7337                 btrfs_free_reserved_bytes(cache, buf->len, 0);
7338                 btrfs_put_block_group(cache);
7339                 trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
7340         }
7341 out:
7342         if (pin)
7343                 add_pinned_bytes(fs_info, buf->len, btrfs_header_level(buf),
7344                                  root->root_key.objectid);
7345
7346         if (last_ref) {
7347                 /*
7348                  * Deleting the buffer, clear the corrupt flag since it doesn't
7349                  * matter anymore.
7350                  */
7351                 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
7352         }
7353 }
7354
7355 /* Can return -ENOMEM */
7356 int btrfs_free_extent(struct btrfs_trans_handle *trans,
7357                       struct btrfs_fs_info *fs_info,
7358                       u64 bytenr, u64 num_bytes, u64 parent, u64 root_objectid,
7359                       u64 owner, u64 offset)
7360 {
7361         int old_ref_mod, new_ref_mod;
7362         int ret;
7363
7364         if (btrfs_is_testing(fs_info))
7365                 return 0;
7366
7367
7368         /*
7369          * tree log blocks never actually go into the extent allocation
7370          * tree, just update pinning info and exit early.
7371          */
7372         if (root_objectid == BTRFS_TREE_LOG_OBJECTID) {
7373                 WARN_ON(owner >= BTRFS_FIRST_FREE_OBJECTID);
7374                 /* unlocks the pinned mutex */
7375                 btrfs_pin_extent(fs_info, bytenr, num_bytes, 1);
7376                 old_ref_mod = new_ref_mod = 0;
7377                 ret = 0;
7378         } else if (owner < BTRFS_FIRST_FREE_OBJECTID) {
7379                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, bytenr,
7380                                                  num_bytes, parent,
7381                                                  root_objectid, (int)owner,
7382                                                  BTRFS_DROP_DELAYED_REF, NULL,
7383                                                  &old_ref_mod, &new_ref_mod);
7384         } else {
7385                 ret = btrfs_add_delayed_data_ref(fs_info, trans, bytenr,
7386                                                  num_bytes, parent,
7387                                                  root_objectid, owner, offset,
7388                                                  0, BTRFS_DROP_DELAYED_REF,
7389                                                  &old_ref_mod, &new_ref_mod);
7390         }
7391
7392         if (ret == 0 && old_ref_mod >= 0 && new_ref_mod < 0)
7393                 add_pinned_bytes(fs_info, num_bytes, owner, root_objectid);
7394
7395         return ret;
7396 }
7397
7398 /*
7399  * when we wait for progress in the block group caching, its because
7400  * our allocation attempt failed at least once.  So, we must sleep
7401  * and let some progress happen before we try again.
7402  *
7403  * This function will sleep at least once waiting for new free space to
7404  * show up, and then it will check the block group free space numbers
7405  * for our min num_bytes.  Another option is to have it go ahead
7406  * and look in the rbtree for a free extent of a given size, but this
7407  * is a good start.
7408  *
7409  * Callers of this must check if cache->cached == BTRFS_CACHE_ERROR before using
7410  * any of the information in this block group.
7411  */
7412 static noinline void
7413 wait_block_group_cache_progress(struct btrfs_block_group_cache *cache,
7414                                 u64 num_bytes)
7415 {
7416         struct btrfs_caching_control *caching_ctl;
7417
7418         caching_ctl = get_caching_control(cache);
7419         if (!caching_ctl)
7420                 return;
7421
7422         wait_event(caching_ctl->wait, block_group_cache_done(cache) ||
7423                    (cache->free_space_ctl->free_space >= num_bytes));
7424
7425         put_caching_control(caching_ctl);
7426 }
7427
7428 static noinline int
7429 wait_block_group_cache_done(struct btrfs_block_group_cache *cache)
7430 {
7431         struct btrfs_caching_control *caching_ctl;
7432         int ret = 0;
7433
7434         caching_ctl = get_caching_control(cache);
7435         if (!caching_ctl)
7436                 return (cache->cached == BTRFS_CACHE_ERROR) ? -EIO : 0;
7437
7438         wait_event(caching_ctl->wait, block_group_cache_done(cache));
7439         if (cache->cached == BTRFS_CACHE_ERROR)
7440                 ret = -EIO;
7441         put_caching_control(caching_ctl);
7442         return ret;
7443 }
7444
7445 int __get_raid_index(u64 flags)
7446 {
7447         if (flags & BTRFS_BLOCK_GROUP_RAID10)
7448                 return BTRFS_RAID_RAID10;
7449         else if (flags & BTRFS_BLOCK_GROUP_RAID1)
7450                 return BTRFS_RAID_RAID1;
7451         else if (flags & BTRFS_BLOCK_GROUP_DUP)
7452                 return BTRFS_RAID_DUP;
7453         else if (flags & BTRFS_BLOCK_GROUP_RAID0)
7454                 return BTRFS_RAID_RAID0;
7455         else if (flags & BTRFS_BLOCK_GROUP_RAID5)
7456                 return BTRFS_RAID_RAID5;
7457         else if (flags & BTRFS_BLOCK_GROUP_RAID6)
7458                 return BTRFS_RAID_RAID6;
7459
7460         return BTRFS_RAID_SINGLE; /* BTRFS_BLOCK_GROUP_SINGLE */
7461 }
7462
7463 int get_block_group_index(struct btrfs_block_group_cache *cache)
7464 {
7465         return __get_raid_index(cache->flags);
7466 }
7467
7468 static const char *btrfs_raid_type_names[BTRFS_NR_RAID_TYPES] = {
7469         [BTRFS_RAID_RAID10]     = "raid10",
7470         [BTRFS_RAID_RAID1]      = "raid1",
7471         [BTRFS_RAID_DUP]        = "dup",
7472         [BTRFS_RAID_RAID0]      = "raid0",
7473         [BTRFS_RAID_SINGLE]     = "single",
7474         [BTRFS_RAID_RAID5]      = "raid5",
7475         [BTRFS_RAID_RAID6]      = "raid6",
7476 };
7477
7478 static const char *get_raid_name(enum btrfs_raid_types type)
7479 {
7480         if (type >= BTRFS_NR_RAID_TYPES)
7481                 return NULL;
7482
7483         return btrfs_raid_type_names[type];
7484 }
7485
7486 enum btrfs_loop_type {
7487         LOOP_CACHING_NOWAIT = 0,
7488         LOOP_CACHING_WAIT = 1,
7489         LOOP_ALLOC_CHUNK = 2,
7490         LOOP_NO_EMPTY_SIZE = 3,
7491 };
7492
7493 static inline void
7494 btrfs_lock_block_group(struct btrfs_block_group_cache *cache,
7495                        int delalloc)
7496 {
7497         if (delalloc)
7498                 down_read(&cache->data_rwsem);
7499 }
7500
7501 static inline void
7502 btrfs_grab_block_group(struct btrfs_block_group_cache *cache,
7503                        int delalloc)
7504 {
7505         btrfs_get_block_group(cache);
7506         if (delalloc)
7507                 down_read(&cache->data_rwsem);
7508 }
7509
7510 static struct btrfs_block_group_cache *
7511 btrfs_lock_cluster(struct btrfs_block_group_cache *block_group,
7512                    struct btrfs_free_cluster *cluster,
7513                    int delalloc)
7514 {
7515         struct btrfs_block_group_cache *used_bg = NULL;
7516
7517         spin_lock(&cluster->refill_lock);
7518         while (1) {
7519                 used_bg = cluster->block_group;
7520                 if (!used_bg)
7521                         return NULL;
7522
7523                 if (used_bg == block_group)
7524                         return used_bg;
7525
7526                 btrfs_get_block_group(used_bg);
7527
7528                 if (!delalloc)
7529                         return used_bg;
7530
7531                 if (down_read_trylock(&used_bg->data_rwsem))
7532                         return used_bg;
7533
7534                 spin_unlock(&cluster->refill_lock);
7535
7536                 /* We should only have one-level nested. */
7537                 down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
7538
7539                 spin_lock(&cluster->refill_lock);
7540                 if (used_bg == cluster->block_group)
7541                         return used_bg;
7542
7543                 up_read(&used_bg->data_rwsem);
7544                 btrfs_put_block_group(used_bg);
7545         }
7546 }
7547
7548 static inline void
7549 btrfs_release_block_group(struct btrfs_block_group_cache *cache,
7550                          int delalloc)
7551 {
7552         if (delalloc)
7553                 up_read(&cache->data_rwsem);
7554         btrfs_put_block_group(cache);
7555 }
7556
7557 /*
7558  * walks the btree of allocated extents and find a hole of a given size.
7559  * The key ins is changed to record the hole:
7560  * ins->objectid == start position
7561  * ins->flags = BTRFS_EXTENT_ITEM_KEY
7562  * ins->offset == the size of the hole.
7563  * Any available blocks before search_start are skipped.
7564  *
7565  * If there is no suitable free space, we will record the max size of
7566  * the free space extent currently.
7567  */
7568 static noinline int find_free_extent(struct btrfs_fs_info *fs_info,
7569                                 u64 ram_bytes, u64 num_bytes, u64 empty_size,
7570                                 u64 hint_byte, struct btrfs_key *ins,
7571                                 u64 flags, int delalloc)
7572 {
7573         int ret = 0;
7574         struct btrfs_root *root = fs_info->extent_root;
7575         struct btrfs_free_cluster *last_ptr = NULL;
7576         struct btrfs_block_group_cache *block_group = NULL;
7577         u64 search_start = 0;
7578         u64 max_extent_size = 0;
7579         u64 max_free_space = 0;
7580         u64 empty_cluster = 0;
7581         struct btrfs_space_info *space_info;
7582         int loop = 0;
7583         int index = __get_raid_index(flags);
7584         bool failed_cluster_refill = false;
7585         bool failed_alloc = false;
7586         bool use_cluster = true;
7587         bool have_caching_bg = false;
7588         bool orig_have_caching_bg = false;
7589         bool full_search = false;
7590
7591         WARN_ON(num_bytes < fs_info->sectorsize);
7592         ins->type = BTRFS_EXTENT_ITEM_KEY;
7593         ins->objectid = 0;
7594         ins->offset = 0;
7595
7596         trace_find_free_extent(fs_info, num_bytes, empty_size, flags);
7597
7598         space_info = __find_space_info(fs_info, flags);
7599         if (!space_info) {
7600                 btrfs_err(fs_info, "No space info for %llu", flags);
7601                 return -ENOSPC;
7602         }
7603
7604         /*
7605          * If our free space is heavily fragmented we may not be able to make
7606          * big contiguous allocations, so instead of doing the expensive search
7607          * for free space, simply return ENOSPC with our max_extent_size so we
7608          * can go ahead and search for a more manageable chunk.
7609          *
7610          * If our max_extent_size is large enough for our allocation simply
7611          * disable clustering since we will likely not be able to find enough
7612          * space to create a cluster and induce latency trying.
7613          */
7614         if (unlikely(space_info->max_extent_size)) {
7615                 spin_lock(&space_info->lock);
7616                 if (space_info->max_extent_size &&
7617                     num_bytes > space_info->max_extent_size) {
7618                         ins->offset = space_info->max_extent_size;
7619                         spin_unlock(&space_info->lock);
7620                         return -ENOSPC;
7621                 } else if (space_info->max_extent_size) {
7622                         use_cluster = false;
7623                 }
7624                 spin_unlock(&space_info->lock);
7625         }
7626
7627         last_ptr = fetch_cluster_info(fs_info, space_info, &empty_cluster);
7628         if (last_ptr) {
7629                 spin_lock(&last_ptr->lock);
7630                 if (last_ptr->block_group)
7631                         hint_byte = last_ptr->window_start;
7632                 if (last_ptr->fragmented) {
7633                         /*
7634                          * We still set window_start so we can keep track of the
7635                          * last place we found an allocation to try and save
7636                          * some time.
7637                          */
7638                         hint_byte = last_ptr->window_start;
7639                         use_cluster = false;
7640                 }
7641                 spin_unlock(&last_ptr->lock);
7642         }
7643
7644         search_start = max(search_start, first_logical_byte(fs_info, 0));
7645         search_start = max(search_start, hint_byte);
7646         if (search_start == hint_byte) {
7647                 block_group = btrfs_lookup_block_group(fs_info, search_start);
7648                 /*
7649                  * we don't want to use the block group if it doesn't match our
7650                  * allocation bits, or if its not cached.
7651                  *
7652                  * However if we are re-searching with an ideal block group
7653                  * picked out then we don't care that the block group is cached.
7654                  */
7655                 if (block_group && block_group_bits(block_group, flags) &&
7656                     block_group->cached != BTRFS_CACHE_NO) {
7657                         down_read(&space_info->groups_sem);
7658                         if (list_empty(&block_group->list) ||
7659                             block_group->ro) {
7660                                 /*
7661                                  * someone is removing this block group,
7662                                  * we can't jump into the have_block_group
7663                                  * target because our list pointers are not
7664                                  * valid
7665                                  */
7666                                 btrfs_put_block_group(block_group);
7667                                 up_read(&space_info->groups_sem);
7668                         } else {
7669                                 index = get_block_group_index(block_group);
7670                                 btrfs_lock_block_group(block_group, delalloc);
7671                                 goto have_block_group;
7672                         }
7673                 } else if (block_group) {
7674                         btrfs_put_block_group(block_group);
7675                 }
7676         }
7677 search:
7678         have_caching_bg = false;
7679         if (index == 0 || index == __get_raid_index(flags))
7680                 full_search = true;
7681         down_read(&space_info->groups_sem);
7682         list_for_each_entry(block_group, &space_info->block_groups[index],
7683                             list) {
7684                 u64 offset;
7685                 int cached;
7686
7687                 /* If the block group is read-only, we can skip it entirely. */
7688                 if (unlikely(block_group->ro))
7689                         continue;
7690
7691                 btrfs_grab_block_group(block_group, delalloc);
7692                 search_start = block_group->key.objectid;
7693
7694                 /*
7695                  * this can happen if we end up cycling through all the
7696                  * raid types, but we want to make sure we only allocate
7697                  * for the proper type.
7698                  */
7699                 if (!block_group_bits(block_group, flags)) {
7700                     u64 extra = BTRFS_BLOCK_GROUP_DUP |
7701                                 BTRFS_BLOCK_GROUP_RAID1 |
7702                                 BTRFS_BLOCK_GROUP_RAID5 |
7703                                 BTRFS_BLOCK_GROUP_RAID6 |
7704                                 BTRFS_BLOCK_GROUP_RAID10;
7705
7706                         /*
7707                          * if they asked for extra copies and this block group
7708                          * doesn't provide them, bail.  This does allow us to
7709                          * fill raid0 from raid1.
7710                          */
7711                         if ((flags & extra) && !(block_group->flags & extra))
7712                                 goto loop;
7713
7714                         /*
7715                          * This block group has different flags than we want.
7716                          * It's possible that we have MIXED_GROUP flag but no
7717                          * block group is mixed.  Just skip such block group.
7718                          */
7719                         btrfs_release_block_group(block_group, delalloc);
7720                         continue;
7721                 }
7722
7723 have_block_group:
7724                 cached = block_group_cache_done(block_group);
7725                 if (unlikely(!cached)) {
7726                         have_caching_bg = true;
7727                         ret = cache_block_group(block_group, 0);
7728                         BUG_ON(ret < 0);
7729                         ret = 0;
7730                 }
7731
7732                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
7733                         goto loop;
7734
7735                 /*
7736                  * Ok we want to try and use the cluster allocator, so
7737                  * lets look there
7738                  */
7739                 if (last_ptr && use_cluster) {
7740                         struct btrfs_block_group_cache *used_block_group;
7741                         unsigned long aligned_cluster;
7742                         /*
7743                          * the refill lock keeps out other
7744                          * people trying to start a new cluster
7745                          */
7746                         used_block_group = btrfs_lock_cluster(block_group,
7747                                                               last_ptr,
7748                                                               delalloc);
7749                         if (!used_block_group)
7750                                 goto refill_cluster;
7751
7752                         if (used_block_group != block_group &&
7753                             (used_block_group->ro ||
7754                              !block_group_bits(used_block_group, flags)))
7755                                 goto release_cluster;
7756
7757                         offset = btrfs_alloc_from_cluster(used_block_group,
7758                                                 last_ptr,
7759                                                 num_bytes,
7760                                                 used_block_group->key.objectid,
7761                                                 &max_extent_size);
7762                         if (offset) {
7763                                 /* we have a block, we're done */
7764                                 spin_unlock(&last_ptr->refill_lock);
7765                                 trace_btrfs_reserve_extent_cluster(fs_info,
7766                                                 used_block_group,
7767                                                 search_start, num_bytes);
7768                                 if (used_block_group != block_group) {
7769                                         btrfs_release_block_group(block_group,
7770                                                                   delalloc);
7771                                         block_group = used_block_group;
7772                                 }
7773                                 goto checks;
7774                         }
7775
7776                         WARN_ON(last_ptr->block_group != used_block_group);
7777 release_cluster:
7778                         /* If we are on LOOP_NO_EMPTY_SIZE, we can't
7779                          * set up a new clusters, so lets just skip it
7780                          * and let the allocator find whatever block
7781                          * it can find.  If we reach this point, we
7782                          * will have tried the cluster allocator
7783                          * plenty of times and not have found
7784                          * anything, so we are likely way too
7785                          * fragmented for the clustering stuff to find
7786                          * anything.
7787                          *
7788                          * However, if the cluster is taken from the
7789                          * current block group, release the cluster
7790                          * first, so that we stand a better chance of
7791                          * succeeding in the unclustered
7792                          * allocation.  */
7793                         if (loop >= LOOP_NO_EMPTY_SIZE &&
7794                             used_block_group != block_group) {
7795                                 spin_unlock(&last_ptr->refill_lock);
7796                                 btrfs_release_block_group(used_block_group,
7797                                                           delalloc);
7798                                 goto unclustered_alloc;
7799                         }
7800
7801                         /*
7802                          * this cluster didn't work out, free it and
7803                          * start over
7804                          */
7805                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7806
7807                         if (used_block_group != block_group)
7808                                 btrfs_release_block_group(used_block_group,
7809                                                           delalloc);
7810 refill_cluster:
7811                         if (loop >= LOOP_NO_EMPTY_SIZE) {
7812                                 spin_unlock(&last_ptr->refill_lock);
7813                                 goto unclustered_alloc;
7814                         }
7815
7816                         aligned_cluster = max_t(unsigned long,
7817                                                 empty_cluster + empty_size,
7818                                               block_group->full_stripe_len);
7819
7820                         /* allocate a cluster in this block group */
7821                         ret = btrfs_find_space_cluster(fs_info, block_group,
7822                                                        last_ptr, search_start,
7823                                                        num_bytes,
7824                                                        aligned_cluster);
7825                         if (ret == 0) {
7826                                 /*
7827                                  * now pull our allocation out of this
7828                                  * cluster
7829                                  */
7830                                 offset = btrfs_alloc_from_cluster(block_group,
7831                                                         last_ptr,
7832                                                         num_bytes,
7833                                                         search_start,
7834                                                         &max_extent_size);
7835                                 if (offset) {
7836                                         /* we found one, proceed */
7837                                         spin_unlock(&last_ptr->refill_lock);
7838                                         trace_btrfs_reserve_extent_cluster(fs_info,
7839                                                 block_group, search_start,
7840                                                 num_bytes);
7841                                         goto checks;
7842                                 }
7843                         } else if (!cached && loop > LOOP_CACHING_NOWAIT
7844                                    && !failed_cluster_refill) {
7845                                 spin_unlock(&last_ptr->refill_lock);
7846
7847                                 failed_cluster_refill = true;
7848                                 wait_block_group_cache_progress(block_group,
7849                                        num_bytes + empty_cluster + empty_size);
7850                                 goto have_block_group;
7851                         }
7852
7853                         /*
7854                          * at this point we either didn't find a cluster
7855                          * or we weren't able to allocate a block from our
7856                          * cluster.  Free the cluster we've been trying
7857                          * to use, and go to the next block group
7858                          */
7859                         btrfs_return_cluster_to_free_space(NULL, last_ptr);
7860                         spin_unlock(&last_ptr->refill_lock);
7861                         goto loop;
7862                 }
7863
7864 unclustered_alloc:
7865                 /*
7866                  * We are doing an unclustered alloc, set the fragmented flag so
7867                  * we don't bother trying to setup a cluster again until we get
7868                  * more space.
7869                  */
7870                 if (unlikely(last_ptr)) {
7871                         spin_lock(&last_ptr->lock);
7872                         last_ptr->fragmented = 1;
7873                         spin_unlock(&last_ptr->lock);
7874                 }
7875                 if (cached) {
7876                         struct btrfs_free_space_ctl *ctl =
7877                                 block_group->free_space_ctl;
7878
7879                         spin_lock(&ctl->tree_lock);
7880                         if (ctl->free_space <
7881                             num_bytes + empty_cluster + empty_size) {
7882                                 max_free_space = max(max_free_space,
7883                                                      ctl->free_space);
7884                                 spin_unlock(&ctl->tree_lock);
7885                                 goto loop;
7886                         }
7887                         spin_unlock(&ctl->tree_lock);
7888                 }
7889
7890                 offset = btrfs_find_space_for_alloc(block_group, search_start,
7891                                                     num_bytes, empty_size,
7892                                                     &max_extent_size);
7893                 /*
7894                  * If we didn't find a chunk, and we haven't failed on this
7895                  * block group before, and this block group is in the middle of
7896                  * caching and we are ok with waiting, then go ahead and wait
7897                  * for progress to be made, and set failed_alloc to true.
7898                  *
7899                  * If failed_alloc is true then we've already waited on this
7900                  * block group once and should move on to the next block group.
7901                  */
7902                 if (!offset && !failed_alloc && !cached &&
7903                     loop > LOOP_CACHING_NOWAIT) {
7904                         wait_block_group_cache_progress(block_group,
7905                                                 num_bytes + empty_size);
7906                         failed_alloc = true;
7907                         goto have_block_group;
7908                 } else if (!offset) {
7909                         goto loop;
7910                 }
7911 checks:
7912                 search_start = ALIGN(offset, fs_info->stripesize);
7913
7914                 /* move on to the next group */
7915                 if (search_start + num_bytes >
7916                     block_group->key.objectid + block_group->key.offset) {
7917                         btrfs_add_free_space(block_group, offset, num_bytes);
7918                         goto loop;
7919                 }
7920
7921                 if (offset < search_start)
7922                         btrfs_add_free_space(block_group, offset,
7923                                              search_start - offset);
7924                 BUG_ON(offset > search_start);
7925
7926                 ret = btrfs_add_reserved_bytes(block_group, ram_bytes,
7927                                 num_bytes, delalloc);
7928                 if (ret == -EAGAIN) {
7929                         btrfs_add_free_space(block_group, offset, num_bytes);
7930                         goto loop;
7931                 }
7932                 btrfs_inc_block_group_reservations(block_group);
7933
7934                 /* we are all good, lets return */
7935                 ins->objectid = search_start;
7936                 ins->offset = num_bytes;
7937
7938                 trace_btrfs_reserve_extent(fs_info, block_group,
7939                                            search_start, num_bytes);
7940                 btrfs_release_block_group(block_group, delalloc);
7941                 break;
7942 loop:
7943                 failed_cluster_refill = false;
7944                 failed_alloc = false;
7945                 BUG_ON(index != get_block_group_index(block_group));
7946                 btrfs_release_block_group(block_group, delalloc);
7947                 cond_resched();
7948         }
7949         up_read(&space_info->groups_sem);
7950
7951         if ((loop == LOOP_CACHING_NOWAIT) && have_caching_bg
7952                 && !orig_have_caching_bg)
7953                 orig_have_caching_bg = true;
7954
7955         if (!ins->objectid && loop >= LOOP_CACHING_WAIT && have_caching_bg)
7956                 goto search;
7957
7958         if (!ins->objectid && ++index < BTRFS_NR_RAID_TYPES)
7959                 goto search;
7960
7961         /*
7962          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
7963          *                      caching kthreads as we move along
7964          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
7965          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
7966          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
7967          *                      again
7968          */
7969         if (!ins->objectid && loop < LOOP_NO_EMPTY_SIZE) {
7970                 index = 0;
7971                 if (loop == LOOP_CACHING_NOWAIT) {
7972                         /*
7973                          * We want to skip the LOOP_CACHING_WAIT step if we
7974                          * don't have any uncached bgs and we've already done a
7975                          * full search through.
7976                          */
7977                         if (orig_have_caching_bg || !full_search)
7978                                 loop = LOOP_CACHING_WAIT;
7979                         else
7980                                 loop = LOOP_ALLOC_CHUNK;
7981                 } else {
7982                         loop++;
7983                 }
7984
7985                 if (loop == LOOP_ALLOC_CHUNK) {
7986                         struct btrfs_trans_handle *trans;
7987                         int exist = 0;
7988
7989                         trans = current->journal_info;
7990                         if (trans)
7991                                 exist = 1;
7992                         else
7993                                 trans = btrfs_join_transaction(root);
7994
7995                         if (IS_ERR(trans)) {
7996                                 ret = PTR_ERR(trans);
7997                                 goto out;
7998                         }
7999
8000                         ret = do_chunk_alloc(trans, fs_info, flags,
8001                                              CHUNK_ALLOC_FORCE);
8002
8003                         /*
8004                          * If we can't allocate a new chunk we've already looped
8005                          * through at least once, move on to the NO_EMPTY_SIZE
8006                          * case.
8007                          */
8008                         if (ret == -ENOSPC)
8009                                 loop = LOOP_NO_EMPTY_SIZE;
8010
8011                         /*
8012                          * Do not bail out on ENOSPC since we
8013                          * can do more things.
8014                          */
8015                         if (ret < 0 && ret != -ENOSPC)
8016                                 btrfs_abort_transaction(trans, ret);
8017                         else
8018                                 ret = 0;
8019                         if (!exist)
8020                                 btrfs_end_transaction(trans);
8021                         if (ret)
8022                                 goto out;
8023                 }
8024
8025                 if (loop == LOOP_NO_EMPTY_SIZE) {
8026                         /*
8027                          * Don't loop again if we already have no empty_size and
8028                          * no empty_cluster.
8029                          */
8030                         if (empty_size == 0 &&
8031                             empty_cluster == 0) {
8032                                 ret = -ENOSPC;
8033                                 goto out;
8034                         }
8035                         empty_size = 0;
8036                         empty_cluster = 0;
8037                 }
8038
8039                 goto search;
8040         } else if (!ins->objectid) {
8041                 ret = -ENOSPC;
8042         } else if (ins->objectid) {
8043                 if (!use_cluster && last_ptr) {
8044                         spin_lock(&last_ptr->lock);
8045                         last_ptr->window_start = ins->objectid;
8046                         spin_unlock(&last_ptr->lock);
8047                 }
8048                 ret = 0;
8049         }
8050 out:
8051         if (ret == -ENOSPC) {
8052                 if (!max_extent_size)
8053                         max_extent_size = max_free_space;
8054                 spin_lock(&space_info->lock);
8055                 space_info->max_extent_size = max_extent_size;
8056                 spin_unlock(&space_info->lock);
8057                 ins->offset = max_extent_size;
8058         }
8059         return ret;
8060 }
8061
8062 static void dump_space_info(struct btrfs_fs_info *fs_info,
8063                             struct btrfs_space_info *info, u64 bytes,
8064                             int dump_block_groups)
8065 {
8066         struct btrfs_block_group_cache *cache;
8067         int index = 0;
8068
8069         spin_lock(&info->lock);
8070         btrfs_info(fs_info, "space_info %llu has %llu free, is %sfull",
8071                    info->flags,
8072                    info->total_bytes - btrfs_space_info_used(info, true),
8073                    info->full ? "" : "not ");
8074         btrfs_info(fs_info,
8075                 "space_info total=%llu, used=%llu, pinned=%llu, reserved=%llu, may_use=%llu, readonly=%llu",
8076                 info->total_bytes, info->bytes_used, info->bytes_pinned,
8077                 info->bytes_reserved, info->bytes_may_use,
8078                 info->bytes_readonly);
8079         spin_unlock(&info->lock);
8080
8081         if (!dump_block_groups)
8082                 return;
8083
8084         down_read(&info->groups_sem);
8085 again:
8086         list_for_each_entry(cache, &info->block_groups[index], list) {
8087                 spin_lock(&cache->lock);
8088                 btrfs_info(fs_info,
8089                         "block group %llu has %llu bytes, %llu used %llu pinned %llu reserved %s",
8090                         cache->key.objectid, cache->key.offset,
8091                         btrfs_block_group_used(&cache->item), cache->pinned,
8092                         cache->reserved, cache->ro ? "[readonly]" : "");
8093                 btrfs_dump_free_space(cache, bytes);
8094                 spin_unlock(&cache->lock);
8095         }
8096         if (++index < BTRFS_NR_RAID_TYPES)
8097                 goto again;
8098         up_read(&info->groups_sem);
8099 }
8100
8101 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
8102                          u64 num_bytes, u64 min_alloc_size,
8103                          u64 empty_size, u64 hint_byte,
8104                          struct btrfs_key *ins, int is_data, int delalloc)
8105 {
8106         struct btrfs_fs_info *fs_info = root->fs_info;
8107         bool final_tried = num_bytes == min_alloc_size;
8108         u64 flags;
8109         int ret;
8110
8111         flags = get_alloc_profile_by_root(root, is_data);
8112 again:
8113         WARN_ON(num_bytes < fs_info->sectorsize);
8114         ret = find_free_extent(fs_info, ram_bytes, num_bytes, empty_size,
8115                                hint_byte, ins, flags, delalloc);
8116         if (!ret && !is_data) {
8117                 btrfs_dec_block_group_reservations(fs_info, ins->objectid);
8118         } else if (ret == -ENOSPC) {
8119                 if (!final_tried && ins->offset) {
8120                         num_bytes = min(num_bytes >> 1, ins->offset);
8121                         num_bytes = round_down(num_bytes,
8122                                                fs_info->sectorsize);
8123                         num_bytes = max(num_bytes, min_alloc_size);
8124                         ram_bytes = num_bytes;
8125                         if (num_bytes == min_alloc_size)
8126                                 final_tried = true;
8127                         goto again;
8128                 } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8129                         struct btrfs_space_info *sinfo;
8130
8131                         sinfo = __find_space_info(fs_info, flags);
8132                         btrfs_err(fs_info,
8133                                   "allocation failed flags %llu, wanted %llu",
8134                                   flags, num_bytes);
8135                         if (sinfo)
8136                                 dump_space_info(fs_info, sinfo, num_bytes, 1);
8137                 }
8138         }
8139
8140         return ret;
8141 }
8142
8143 static int __btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
8144                                         u64 start, u64 len,
8145                                         int pin, int delalloc)
8146 {
8147         struct btrfs_block_group_cache *cache;
8148         int ret = 0;
8149
8150         cache = btrfs_lookup_block_group(fs_info, start);
8151         if (!cache) {
8152                 btrfs_err(fs_info, "Unable to find block group for %llu",
8153                           start);
8154                 return -ENOSPC;
8155         }
8156
8157         if (pin)
8158                 pin_down_extent(fs_info, cache, start, len, 1);
8159         else {
8160                 if (btrfs_test_opt(fs_info, DISCARD))
8161                         ret = btrfs_discard_extent(fs_info, start, len, NULL);
8162                 btrfs_add_free_space(cache, start, len);
8163                 btrfs_free_reserved_bytes(cache, len, delalloc);
8164                 trace_btrfs_reserved_extent_free(fs_info, start, len);
8165         }
8166
8167         btrfs_put_block_group(cache);
8168         return ret;
8169 }
8170
8171 int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
8172                                u64 start, u64 len, int delalloc)
8173 {
8174         return __btrfs_free_reserved_extent(fs_info, start, len, 0, delalloc);
8175 }
8176
8177 int btrfs_free_and_pin_reserved_extent(struct btrfs_fs_info *fs_info,
8178                                        u64 start, u64 len)
8179 {
8180         return __btrfs_free_reserved_extent(fs_info, start, len, 1, 0);
8181 }
8182
8183 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8184                                       struct btrfs_fs_info *fs_info,
8185                                       u64 parent, u64 root_objectid,
8186                                       u64 flags, u64 owner, u64 offset,
8187                                       struct btrfs_key *ins, int ref_mod)
8188 {
8189         int ret;
8190         struct btrfs_extent_item *extent_item;
8191         struct btrfs_extent_inline_ref *iref;
8192         struct btrfs_path *path;
8193         struct extent_buffer *leaf;
8194         int type;
8195         u32 size;
8196
8197         if (parent > 0)
8198                 type = BTRFS_SHARED_DATA_REF_KEY;
8199         else
8200                 type = BTRFS_EXTENT_DATA_REF_KEY;
8201
8202         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
8203
8204         path = btrfs_alloc_path();
8205         if (!path)
8206                 return -ENOMEM;
8207
8208         path->leave_spinning = 1;
8209         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8210                                       ins, size);
8211         if (ret) {
8212                 btrfs_free_path(path);
8213                 return ret;
8214         }
8215
8216         leaf = path->nodes[0];
8217         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8218                                      struct btrfs_extent_item);
8219         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
8220         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8221         btrfs_set_extent_flags(leaf, extent_item,
8222                                flags | BTRFS_EXTENT_FLAG_DATA);
8223
8224         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8225         btrfs_set_extent_inline_ref_type(leaf, iref, type);
8226         if (parent > 0) {
8227                 struct btrfs_shared_data_ref *ref;
8228                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
8229                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8230                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
8231         } else {
8232                 struct btrfs_extent_data_ref *ref;
8233                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
8234                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
8235                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
8236                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
8237                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
8238         }
8239
8240         btrfs_mark_buffer_dirty(path->nodes[0]);
8241         btrfs_free_path(path);
8242
8243         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8244                                           ins->offset);
8245         if (ret)
8246                 return ret;
8247
8248         ret = update_block_group(trans, fs_info, ins->objectid, ins->offset, 1);
8249         if (ret) { /* -ENOENT, logic error */
8250                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8251                         ins->objectid, ins->offset);
8252                 BUG();
8253         }
8254         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid, ins->offset);
8255         return ret;
8256 }
8257
8258 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
8259                                      struct btrfs_fs_info *fs_info,
8260                                      u64 parent, u64 root_objectid,
8261                                      u64 flags, struct btrfs_disk_key *key,
8262                                      int level, struct btrfs_key *ins)
8263 {
8264         int ret;
8265         struct btrfs_extent_item *extent_item;
8266         struct btrfs_tree_block_info *block_info;
8267         struct btrfs_extent_inline_ref *iref;
8268         struct btrfs_path *path;
8269         struct extent_buffer *leaf;
8270         u32 size = sizeof(*extent_item) + sizeof(*iref);
8271         u64 num_bytes = ins->offset;
8272         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8273
8274         if (!skinny_metadata)
8275                 size += sizeof(*block_info);
8276
8277         path = btrfs_alloc_path();
8278         if (!path) {
8279                 btrfs_free_and_pin_reserved_extent(fs_info, ins->objectid,
8280                                                    fs_info->nodesize);
8281                 return -ENOMEM;
8282         }
8283
8284         path->leave_spinning = 1;
8285         ret = btrfs_insert_empty_item(trans, fs_info->extent_root, path,
8286                                       ins, size);
8287         if (ret) {
8288                 btrfs_free_path(path);
8289                 btrfs_free_and_pin_reserved_extent(fs_info, ins->objectid,
8290                                                    fs_info->nodesize);
8291                 return ret;
8292         }
8293
8294         leaf = path->nodes[0];
8295         extent_item = btrfs_item_ptr(leaf, path->slots[0],
8296                                      struct btrfs_extent_item);
8297         btrfs_set_extent_refs(leaf, extent_item, 1);
8298         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
8299         btrfs_set_extent_flags(leaf, extent_item,
8300                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
8301
8302         if (skinny_metadata) {
8303                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
8304                 num_bytes = fs_info->nodesize;
8305         } else {
8306                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
8307                 btrfs_set_tree_block_key(leaf, block_info, key);
8308                 btrfs_set_tree_block_level(leaf, block_info, level);
8309                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
8310         }
8311
8312         if (parent > 0) {
8313                 BUG_ON(!(flags & BTRFS_BLOCK_FLAG_FULL_BACKREF));
8314                 btrfs_set_extent_inline_ref_type(leaf, iref,
8315                                                  BTRFS_SHARED_BLOCK_REF_KEY);
8316                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
8317         } else {
8318                 btrfs_set_extent_inline_ref_type(leaf, iref,
8319                                                  BTRFS_TREE_BLOCK_REF_KEY);
8320                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
8321         }
8322
8323         btrfs_mark_buffer_dirty(leaf);
8324         btrfs_free_path(path);
8325
8326         ret = remove_from_free_space_tree(trans, fs_info, ins->objectid,
8327                                           num_bytes);
8328         if (ret)
8329                 return ret;
8330
8331         ret = update_block_group(trans, fs_info, ins->objectid,
8332                                  fs_info->nodesize, 1);
8333         if (ret) { /* -ENOENT, logic error */
8334                 btrfs_err(fs_info, "update block group failed for %llu %llu",
8335                         ins->objectid, ins->offset);
8336                 BUG();
8337         }
8338
8339         trace_btrfs_reserved_extent_alloc(fs_info, ins->objectid,
8340                                           fs_info->nodesize);
8341         return ret;
8342 }
8343
8344 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
8345                                      u64 root_objectid, u64 owner,
8346                                      u64 offset, u64 ram_bytes,
8347                                      struct btrfs_key *ins)
8348 {
8349         struct btrfs_fs_info *fs_info = trans->fs_info;
8350         int ret;
8351
8352         BUG_ON(root_objectid == BTRFS_TREE_LOG_OBJECTID);
8353
8354         ret = btrfs_add_delayed_data_ref(fs_info, trans, ins->objectid,
8355                                          ins->offset, 0, root_objectid, owner,
8356                                          offset, ram_bytes,
8357                                          BTRFS_ADD_DELAYED_EXTENT, NULL, NULL);
8358         return ret;
8359 }
8360
8361 /*
8362  * this is used by the tree logging recovery code.  It records that
8363  * an extent has been allocated and makes sure to clear the free
8364  * space cache bits as well
8365  */
8366 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
8367                                    struct btrfs_fs_info *fs_info,
8368                                    u64 root_objectid, u64 owner, u64 offset,
8369                                    struct btrfs_key *ins)
8370 {
8371         int ret;
8372         struct btrfs_block_group_cache *block_group;
8373         struct btrfs_space_info *space_info;
8374
8375         /*
8376          * Mixed block groups will exclude before processing the log so we only
8377          * need to do the exclude dance if this fs isn't mixed.
8378          */
8379         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
8380                 ret = __exclude_logged_extent(fs_info, ins->objectid,
8381                                               ins->offset);
8382                 if (ret)
8383                         return ret;
8384         }
8385
8386         block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
8387         if (!block_group)
8388                 return -EINVAL;
8389
8390         space_info = block_group->space_info;
8391         spin_lock(&space_info->lock);
8392         spin_lock(&block_group->lock);
8393         space_info->bytes_reserved += ins->offset;
8394         block_group->reserved += ins->offset;
8395         spin_unlock(&block_group->lock);
8396         spin_unlock(&space_info->lock);
8397
8398         ret = alloc_reserved_file_extent(trans, fs_info, 0, root_objectid,
8399                                          0, owner, offset, ins, 1);
8400         btrfs_put_block_group(block_group);
8401         return ret;
8402 }
8403
8404 static struct extent_buffer *
8405 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
8406                       u64 bytenr, int level)
8407 {
8408         struct btrfs_fs_info *fs_info = root->fs_info;
8409         struct extent_buffer *buf;
8410
8411         buf = btrfs_find_create_tree_block(fs_info, bytenr);
8412         if (IS_ERR(buf))
8413                 return buf;
8414
8415         /*
8416          * Extra safety check in case the extent tree is corrupted and extent
8417          * allocator chooses to use a tree block which is already used and
8418          * locked.
8419          */
8420         if (buf->lock_owner == current->pid) {
8421                 btrfs_err_rl(fs_info,
8422 "tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
8423                         buf->start, btrfs_header_owner(buf), current->pid);
8424                 free_extent_buffer(buf);
8425                 return ERR_PTR(-EUCLEAN);
8426         }
8427
8428         btrfs_set_header_generation(buf, trans->transid);
8429         btrfs_set_buffer_lockdep_class(root->root_key.objectid, buf, level);
8430         btrfs_tree_lock(buf);
8431         clean_tree_block(fs_info, buf);
8432         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
8433
8434         btrfs_set_lock_blocking(buf);
8435         set_extent_buffer_uptodate(buf);
8436
8437         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
8438                 buf->log_index = root->log_transid % 2;
8439                 /*
8440                  * we allow two log transactions at a time, use different
8441                  * EXENT bit to differentiate dirty pages.
8442                  */
8443                 if (buf->log_index == 0)
8444                         set_extent_dirty(&root->dirty_log_pages, buf->start,
8445                                         buf->start + buf->len - 1, GFP_NOFS);
8446                 else
8447                         set_extent_new(&root->dirty_log_pages, buf->start,
8448                                         buf->start + buf->len - 1);
8449         } else {
8450                 buf->log_index = -1;
8451                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
8452                          buf->start + buf->len - 1, GFP_NOFS);
8453         }
8454         trans->dirty = true;
8455         /* this returns a buffer locked for blocking */
8456         return buf;
8457 }
8458
8459 static struct btrfs_block_rsv *
8460 use_block_rsv(struct btrfs_trans_handle *trans,
8461               struct btrfs_root *root, u32 blocksize)
8462 {
8463         struct btrfs_fs_info *fs_info = root->fs_info;
8464         struct btrfs_block_rsv *block_rsv;
8465         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
8466         int ret;
8467         bool global_updated = false;
8468
8469         block_rsv = get_block_rsv(trans, root);
8470
8471         if (unlikely(block_rsv->size == 0))
8472                 goto try_reserve;
8473 again:
8474         ret = block_rsv_use_bytes(block_rsv, blocksize);
8475         if (!ret)
8476                 return block_rsv;
8477
8478         if (block_rsv->failfast)
8479                 return ERR_PTR(ret);
8480
8481         if (block_rsv->type == BTRFS_BLOCK_RSV_GLOBAL && !global_updated) {
8482                 global_updated = true;
8483                 update_global_block_rsv(fs_info);
8484                 goto again;
8485         }
8486
8487         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
8488                 static DEFINE_RATELIMIT_STATE(_rs,
8489                                 DEFAULT_RATELIMIT_INTERVAL * 10,
8490                                 /*DEFAULT_RATELIMIT_BURST*/ 1);
8491                 if (__ratelimit(&_rs))
8492                         WARN(1, KERN_DEBUG
8493                                 "BTRFS: block rsv returned %d\n", ret);
8494         }
8495 try_reserve:
8496         ret = reserve_metadata_bytes(root, block_rsv, blocksize,
8497                                      BTRFS_RESERVE_NO_FLUSH);
8498         if (!ret)
8499                 return block_rsv;
8500         /*
8501          * If we couldn't reserve metadata bytes try and use some from
8502          * the global reserve if its space type is the same as the global
8503          * reservation.
8504          */
8505         if (block_rsv->type != BTRFS_BLOCK_RSV_GLOBAL &&
8506             block_rsv->space_info == global_rsv->space_info) {
8507                 ret = block_rsv_use_bytes(global_rsv, blocksize);
8508                 if (!ret)
8509                         return global_rsv;
8510         }
8511         return ERR_PTR(ret);
8512 }
8513
8514 static void unuse_block_rsv(struct btrfs_fs_info *fs_info,
8515                             struct btrfs_block_rsv *block_rsv, u32 blocksize)
8516 {
8517         block_rsv_add_bytes(block_rsv, blocksize, 0);
8518         block_rsv_release_bytes(fs_info, block_rsv, NULL, 0);
8519 }
8520
8521 /*
8522  * finds a free extent and does all the dirty work required for allocation
8523  * returns the tree buffer or an ERR_PTR on error.
8524  */
8525 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
8526                                              struct btrfs_root *root,
8527                                              u64 parent, u64 root_objectid,
8528                                              const struct btrfs_disk_key *key,
8529                                              int level, u64 hint,
8530                                              u64 empty_size)
8531 {
8532         struct btrfs_fs_info *fs_info = root->fs_info;
8533         struct btrfs_key ins;
8534         struct btrfs_block_rsv *block_rsv;
8535         struct extent_buffer *buf;
8536         struct btrfs_delayed_extent_op *extent_op;
8537         u64 flags = 0;
8538         int ret;
8539         u32 blocksize = fs_info->nodesize;
8540         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
8541
8542 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
8543         if (btrfs_is_testing(fs_info)) {
8544                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
8545                                             level);
8546                 if (!IS_ERR(buf))
8547                         root->alloc_bytenr += blocksize;
8548                 return buf;
8549         }
8550 #endif
8551
8552         block_rsv = use_block_rsv(trans, root, blocksize);
8553         if (IS_ERR(block_rsv))
8554                 return ERR_CAST(block_rsv);
8555
8556         ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
8557                                    empty_size, hint, &ins, 0, 0);
8558         if (ret)
8559                 goto out_unuse;
8560
8561         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level);
8562         if (IS_ERR(buf)) {
8563                 ret = PTR_ERR(buf);
8564                 goto out_free_reserved;
8565         }
8566
8567         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
8568                 if (parent == 0)
8569                         parent = ins.objectid;
8570                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
8571         } else
8572                 BUG_ON(parent > 0);
8573
8574         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
8575                 extent_op = btrfs_alloc_delayed_extent_op();
8576                 if (!extent_op) {
8577                         ret = -ENOMEM;
8578                         goto out_free_buf;
8579                 }
8580                 if (key)
8581                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
8582                 else
8583                         memset(&extent_op->key, 0, sizeof(extent_op->key));
8584                 extent_op->flags_to_set = flags;
8585                 extent_op->update_key = skinny_metadata ? false : true;
8586                 extent_op->update_flags = true;
8587                 extent_op->is_data = false;
8588                 extent_op->level = level;
8589
8590                 ret = btrfs_add_delayed_tree_ref(fs_info, trans, ins.objectid,
8591                                                  ins.offset, parent,
8592                                                  root_objectid, level,
8593                                                  BTRFS_ADD_DELAYED_EXTENT,
8594                                                  extent_op, NULL, NULL);
8595                 if (ret)
8596                         goto out_free_delayed;
8597         }
8598         return buf;
8599
8600 out_free_delayed:
8601         btrfs_free_delayed_extent_op(extent_op);
8602 out_free_buf:
8603         btrfs_tree_unlock(buf);
8604         free_extent_buffer(buf);
8605 out_free_reserved:
8606         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
8607 out_unuse:
8608         unuse_block_rsv(fs_info, block_rsv, blocksize);
8609         return ERR_PTR(ret);
8610 }
8611
8612 struct walk_control {
8613         u64 refs[BTRFS_MAX_LEVEL];
8614         u64 flags[BTRFS_MAX_LEVEL];
8615         struct btrfs_key update_progress;
8616         int stage;
8617         int level;
8618         int shared_level;
8619         int update_ref;
8620         int keep_locks;
8621         int reada_slot;
8622         int reada_count;
8623         int for_reloc;
8624 };
8625
8626 #define DROP_REFERENCE  1
8627 #define UPDATE_BACKREF  2
8628
8629 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
8630                                      struct btrfs_root *root,
8631                                      struct walk_control *wc,
8632                                      struct btrfs_path *path)
8633 {
8634         struct btrfs_fs_info *fs_info = root->fs_info;
8635         u64 bytenr;
8636         u64 generation;
8637         u64 refs;
8638         u64 flags;
8639         u32 nritems;
8640         struct btrfs_key key;
8641         struct extent_buffer *eb;
8642         int ret;
8643         int slot;
8644         int nread = 0;
8645
8646         if (path->slots[wc->level] < wc->reada_slot) {
8647                 wc->reada_count = wc->reada_count * 2 / 3;
8648                 wc->reada_count = max(wc->reada_count, 2);
8649         } else {
8650                 wc->reada_count = wc->reada_count * 3 / 2;
8651                 wc->reada_count = min_t(int, wc->reada_count,
8652                                         BTRFS_NODEPTRS_PER_BLOCK(fs_info));
8653         }
8654
8655         eb = path->nodes[wc->level];
8656         nritems = btrfs_header_nritems(eb);
8657
8658         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
8659                 if (nread >= wc->reada_count)
8660                         break;
8661
8662                 cond_resched();
8663                 bytenr = btrfs_node_blockptr(eb, slot);
8664                 generation = btrfs_node_ptr_generation(eb, slot);
8665
8666                 if (slot == path->slots[wc->level])
8667                         goto reada;
8668
8669                 if (wc->stage == UPDATE_BACKREF &&
8670                     generation <= root->root_key.offset)
8671                         continue;
8672
8673                 /* We don't lock the tree block, it's OK to be racy here */
8674                 ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
8675                                                wc->level - 1, 1, &refs,
8676                                                &flags);
8677                 /* We don't care about errors in readahead. */
8678                 if (ret < 0)
8679                         continue;
8680                 BUG_ON(refs == 0);
8681
8682                 if (wc->stage == DROP_REFERENCE) {
8683                         if (refs == 1)
8684                                 goto reada;
8685
8686                         if (wc->level == 1 &&
8687                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8688                                 continue;
8689                         if (!wc->update_ref ||
8690                             generation <= root->root_key.offset)
8691                                 continue;
8692                         btrfs_node_key_to_cpu(eb, &key, slot);
8693                         ret = btrfs_comp_cpu_keys(&key,
8694                                                   &wc->update_progress);
8695                         if (ret < 0)
8696                                 continue;
8697                 } else {
8698                         if (wc->level == 1 &&
8699                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8700                                 continue;
8701                 }
8702 reada:
8703                 readahead_tree_block(fs_info, bytenr);
8704                 nread++;
8705         }
8706         wc->reada_slot = slot;
8707 }
8708
8709 /*
8710  * helper to process tree block while walking down the tree.
8711  *
8712  * when wc->stage == UPDATE_BACKREF, this function updates
8713  * back refs for pointers in the block.
8714  *
8715  * NOTE: return value 1 means we should stop walking down.
8716  */
8717 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
8718                                    struct btrfs_root *root,
8719                                    struct btrfs_path *path,
8720                                    struct walk_control *wc, int lookup_info)
8721 {
8722         struct btrfs_fs_info *fs_info = root->fs_info;
8723         int level = wc->level;
8724         struct extent_buffer *eb = path->nodes[level];
8725         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
8726         int ret;
8727
8728         if (wc->stage == UPDATE_BACKREF &&
8729             btrfs_header_owner(eb) != root->root_key.objectid)
8730                 return 1;
8731
8732         /*
8733          * when reference count of tree block is 1, it won't increase
8734          * again. once full backref flag is set, we never clear it.
8735          */
8736         if (lookup_info &&
8737             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
8738              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
8739                 BUG_ON(!path->locks[level]);
8740                 ret = btrfs_lookup_extent_info(trans, fs_info,
8741                                                eb->start, level, 1,
8742                                                &wc->refs[level],
8743                                                &wc->flags[level]);
8744                 BUG_ON(ret == -ENOMEM);
8745                 if (ret)
8746                         return ret;
8747                 BUG_ON(wc->refs[level] == 0);
8748         }
8749
8750         if (wc->stage == DROP_REFERENCE) {
8751                 if (wc->refs[level] > 1)
8752                         return 1;
8753
8754                 if (path->locks[level] && !wc->keep_locks) {
8755                         btrfs_tree_unlock_rw(eb, path->locks[level]);
8756                         path->locks[level] = 0;
8757                 }
8758                 return 0;
8759         }
8760
8761         /* wc->stage == UPDATE_BACKREF */
8762         if (!(wc->flags[level] & flag)) {
8763                 BUG_ON(!path->locks[level]);
8764                 ret = btrfs_inc_ref(trans, root, eb, 1);
8765                 BUG_ON(ret); /* -ENOMEM */
8766                 ret = btrfs_dec_ref(trans, root, eb, 0);
8767                 BUG_ON(ret); /* -ENOMEM */
8768                 ret = btrfs_set_disk_extent_flags(trans, fs_info, eb->start,
8769                                                   eb->len, flag,
8770                                                   btrfs_header_level(eb), 0);
8771                 BUG_ON(ret); /* -ENOMEM */
8772                 wc->flags[level] |= flag;
8773         }
8774
8775         /*
8776          * the block is shared by multiple trees, so it's not good to
8777          * keep the tree lock
8778          */
8779         if (path->locks[level] && level > 0) {
8780                 btrfs_tree_unlock_rw(eb, path->locks[level]);
8781                 path->locks[level] = 0;
8782         }
8783         return 0;
8784 }
8785
8786 /*
8787  * helper to process tree block pointer.
8788  *
8789  * when wc->stage == DROP_REFERENCE, this function checks
8790  * reference count of the block pointed to. if the block
8791  * is shared and we need update back refs for the subtree
8792  * rooted at the block, this function changes wc->stage to
8793  * UPDATE_BACKREF. if the block is shared and there is no
8794  * need to update back, this function drops the reference
8795  * to the block.
8796  *
8797  * NOTE: return value 1 means we should stop walking down.
8798  */
8799 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
8800                                  struct btrfs_root *root,
8801                                  struct btrfs_path *path,
8802                                  struct walk_control *wc, int *lookup_info)
8803 {
8804         struct btrfs_fs_info *fs_info = root->fs_info;
8805         u64 bytenr;
8806         u64 generation;
8807         u64 parent;
8808         u32 blocksize;
8809         struct btrfs_key key;
8810         struct extent_buffer *next;
8811         int level = wc->level;
8812         int reada = 0;
8813         int ret = 0;
8814         bool need_account = false;
8815
8816         generation = btrfs_node_ptr_generation(path->nodes[level],
8817                                                path->slots[level]);
8818         /*
8819          * if the lower level block was created before the snapshot
8820          * was created, we know there is no need to update back refs
8821          * for the subtree
8822          */
8823         if (wc->stage == UPDATE_BACKREF &&
8824             generation <= root->root_key.offset) {
8825                 *lookup_info = 1;
8826                 return 1;
8827         }
8828
8829         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
8830         blocksize = fs_info->nodesize;
8831
8832         next = find_extent_buffer(fs_info, bytenr);
8833         if (!next) {
8834                 next = btrfs_find_create_tree_block(fs_info, bytenr);
8835                 if (IS_ERR(next))
8836                         return PTR_ERR(next);
8837
8838                 btrfs_set_buffer_lockdep_class(root->root_key.objectid, next,
8839                                                level - 1);
8840                 reada = 1;
8841         }
8842         btrfs_tree_lock(next);
8843         btrfs_set_lock_blocking(next);
8844
8845         ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
8846                                        &wc->refs[level - 1],
8847                                        &wc->flags[level - 1]);
8848         if (ret < 0)
8849                 goto out_unlock;
8850
8851         if (unlikely(wc->refs[level - 1] == 0)) {
8852                 btrfs_err(fs_info, "Missing references.");
8853                 ret = -EIO;
8854                 goto out_unlock;
8855         }
8856         *lookup_info = 0;
8857
8858         if (wc->stage == DROP_REFERENCE) {
8859                 if (wc->refs[level - 1] > 1) {
8860                         need_account = true;
8861                         if (level == 1 &&
8862                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8863                                 goto skip;
8864
8865                         if (!wc->update_ref ||
8866                             generation <= root->root_key.offset)
8867                                 goto skip;
8868
8869                         btrfs_node_key_to_cpu(path->nodes[level], &key,
8870                                               path->slots[level]);
8871                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
8872                         if (ret < 0)
8873                                 goto skip;
8874
8875                         wc->stage = UPDATE_BACKREF;
8876                         wc->shared_level = level - 1;
8877                 }
8878         } else {
8879                 if (level == 1 &&
8880                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
8881                         goto skip;
8882         }
8883
8884         if (!btrfs_buffer_uptodate(next, generation, 0)) {
8885                 btrfs_tree_unlock(next);
8886                 free_extent_buffer(next);
8887                 next = NULL;
8888                 *lookup_info = 1;
8889         }
8890
8891         if (!next) {
8892                 if (reada && level == 1)
8893                         reada_walk_down(trans, root, wc, path);
8894                 next = read_tree_block(fs_info, bytenr, generation);
8895                 if (IS_ERR(next)) {
8896                         return PTR_ERR(next);
8897                 } else if (!extent_buffer_uptodate(next)) {
8898                         free_extent_buffer(next);
8899                         return -EIO;
8900                 }
8901                 btrfs_tree_lock(next);
8902                 btrfs_set_lock_blocking(next);
8903         }
8904
8905         level--;
8906         ASSERT(level == btrfs_header_level(next));
8907         if (level != btrfs_header_level(next)) {
8908                 btrfs_err(root->fs_info, "mismatched level");
8909                 ret = -EIO;
8910                 goto out_unlock;
8911         }
8912         path->nodes[level] = next;
8913         path->slots[level] = 0;
8914         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
8915         wc->level = level;
8916         if (wc->level == 1)
8917                 wc->reada_slot = 0;
8918         return 0;
8919 skip:
8920         wc->refs[level - 1] = 0;
8921         wc->flags[level - 1] = 0;
8922         if (wc->stage == DROP_REFERENCE) {
8923                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
8924                         parent = path->nodes[level]->start;
8925                 } else {
8926                         ASSERT(root->root_key.objectid ==
8927                                btrfs_header_owner(path->nodes[level]));
8928                         if (root->root_key.objectid !=
8929                             btrfs_header_owner(path->nodes[level])) {
8930                                 btrfs_err(root->fs_info,
8931                                                 "mismatched block owner");
8932                                 ret = -EIO;
8933                                 goto out_unlock;
8934                         }
8935                         parent = 0;
8936                 }
8937
8938                 if (need_account) {
8939                         ret = btrfs_qgroup_trace_subtree(trans, root, next,
8940                                                          generation, level - 1);
8941                         if (ret) {
8942                                 btrfs_err_rl(fs_info,
8943                                              "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
8944                                              ret);
8945                         }
8946                 }
8947                 ret = btrfs_free_extent(trans, fs_info, bytenr, blocksize,
8948                                         parent, root->root_key.objectid,
8949                                         level - 1, 0);
8950                 if (ret)
8951                         goto out_unlock;
8952         }
8953
8954         *lookup_info = 1;
8955         ret = 1;
8956
8957 out_unlock:
8958         btrfs_tree_unlock(next);
8959         free_extent_buffer(next);
8960
8961         return ret;
8962 }
8963
8964 /*
8965  * helper to process tree block while walking up the tree.
8966  *
8967  * when wc->stage == DROP_REFERENCE, this function drops
8968  * reference count on the block.
8969  *
8970  * when wc->stage == UPDATE_BACKREF, this function changes
8971  * wc->stage back to DROP_REFERENCE if we changed wc->stage
8972  * to UPDATE_BACKREF previously while processing the block.
8973  *
8974  * NOTE: return value 1 means we should stop walking up.
8975  */
8976 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
8977                                  struct btrfs_root *root,
8978                                  struct btrfs_path *path,
8979                                  struct walk_control *wc)
8980 {
8981         struct btrfs_fs_info *fs_info = root->fs_info;
8982         int ret;
8983         int level = wc->level;
8984         struct extent_buffer *eb = path->nodes[level];
8985         u64 parent = 0;
8986
8987         if (wc->stage == UPDATE_BACKREF) {
8988                 BUG_ON(wc->shared_level < level);
8989                 if (level < wc->shared_level)
8990                         goto out;
8991
8992                 ret = find_next_key(path, level + 1, &wc->update_progress);
8993                 if (ret > 0)
8994                         wc->update_ref = 0;
8995
8996                 wc->stage = DROP_REFERENCE;
8997                 wc->shared_level = -1;
8998                 path->slots[level] = 0;
8999
9000                 /*
9001                  * check reference count again if the block isn't locked.
9002                  * we should start walking down the tree again if reference
9003                  * count is one.
9004                  */
9005                 if (!path->locks[level]) {
9006                         BUG_ON(level == 0);
9007                         btrfs_tree_lock(eb);
9008                         btrfs_set_lock_blocking(eb);
9009                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9010
9011                         ret = btrfs_lookup_extent_info(trans, fs_info,
9012                                                        eb->start, level, 1,
9013                                                        &wc->refs[level],
9014                                                        &wc->flags[level]);
9015                         if (ret < 0) {
9016                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
9017                                 path->locks[level] = 0;
9018                                 return ret;
9019                         }
9020                         BUG_ON(wc->refs[level] == 0);
9021                         if (wc->refs[level] == 1) {
9022                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
9023                                 path->locks[level] = 0;
9024                                 return 1;
9025                         }
9026                 }
9027         }
9028
9029         /* wc->stage == DROP_REFERENCE */
9030         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
9031
9032         if (wc->refs[level] == 1) {
9033                 if (level == 0) {
9034                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9035                                 ret = btrfs_dec_ref(trans, root, eb, 1);
9036                         else
9037                                 ret = btrfs_dec_ref(trans, root, eb, 0);
9038                         BUG_ON(ret); /* -ENOMEM */
9039                         ret = btrfs_qgroup_trace_leaf_items(trans, fs_info, eb);
9040                         if (ret) {
9041                                 btrfs_err_rl(fs_info,
9042                                              "error %d accounting leaf items. Quota is out of sync, rescan required.",
9043                                              ret);
9044                         }
9045                 }
9046                 /* make block locked assertion in clean_tree_block happy */
9047                 if (!path->locks[level] &&
9048                     btrfs_header_generation(eb) == trans->transid) {
9049                         btrfs_tree_lock(eb);
9050                         btrfs_set_lock_blocking(eb);
9051                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9052                 }
9053                 clean_tree_block(fs_info, eb);
9054         }
9055
9056         if (eb == root->node) {
9057                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9058                         parent = eb->start;
9059                 else if (root->root_key.objectid != btrfs_header_owner(eb))
9060                         goto owner_mismatch;
9061         } else {
9062                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
9063                         parent = path->nodes[level + 1]->start;
9064                 else if (root->root_key.objectid !=
9065                          btrfs_header_owner(path->nodes[level + 1]))
9066                         goto owner_mismatch;
9067         }
9068
9069         btrfs_free_tree_block(trans, root, eb, parent, wc->refs[level] == 1);
9070 out:
9071         wc->refs[level] = 0;
9072         wc->flags[level] = 0;
9073         return 0;
9074
9075 owner_mismatch:
9076         btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
9077                      btrfs_header_owner(eb), root->root_key.objectid);
9078         return -EUCLEAN;
9079 }
9080
9081 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
9082                                    struct btrfs_root *root,
9083                                    struct btrfs_path *path,
9084                                    struct walk_control *wc)
9085 {
9086         int level = wc->level;
9087         int lookup_info = 1;
9088         int ret;
9089
9090         while (level >= 0) {
9091                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
9092                 if (ret > 0)
9093                         break;
9094
9095                 if (level == 0)
9096                         break;
9097
9098                 if (path->slots[level] >=
9099                     btrfs_header_nritems(path->nodes[level]))
9100                         break;
9101
9102                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
9103                 if (ret > 0) {
9104                         path->slots[level]++;
9105                         continue;
9106                 } else if (ret < 0)
9107                         return ret;
9108                 level = wc->level;
9109         }
9110         return 0;
9111 }
9112
9113 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
9114                                  struct btrfs_root *root,
9115                                  struct btrfs_path *path,
9116                                  struct walk_control *wc, int max_level)
9117 {
9118         int level = wc->level;
9119         int ret;
9120
9121         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
9122         while (level < max_level && path->nodes[level]) {
9123                 wc->level = level;
9124                 if (path->slots[level] + 1 <
9125                     btrfs_header_nritems(path->nodes[level])) {
9126                         path->slots[level]++;
9127                         return 0;
9128                 } else {
9129                         ret = walk_up_proc(trans, root, path, wc);
9130                         if (ret > 0)
9131                                 return 0;
9132                         if (ret < 0)
9133                                 return ret;
9134
9135                         if (path->locks[level]) {
9136                                 btrfs_tree_unlock_rw(path->nodes[level],
9137                                                      path->locks[level]);
9138                                 path->locks[level] = 0;
9139                         }
9140                         free_extent_buffer(path->nodes[level]);
9141                         path->nodes[level] = NULL;
9142                         level++;
9143                 }
9144         }
9145         return 1;
9146 }
9147
9148 /*
9149  * drop a subvolume tree.
9150  *
9151  * this function traverses the tree freeing any blocks that only
9152  * referenced by the tree.
9153  *
9154  * when a shared tree block is found. this function decreases its
9155  * reference count by one. if update_ref is true, this function
9156  * also make sure backrefs for the shared block and all lower level
9157  * blocks are properly updated.
9158  *
9159  * If called with for_reloc == 0, may exit early with -EAGAIN
9160  */
9161 int btrfs_drop_snapshot(struct btrfs_root *root,
9162                          struct btrfs_block_rsv *block_rsv, int update_ref,
9163                          int for_reloc)
9164 {
9165         struct btrfs_fs_info *fs_info = root->fs_info;
9166         struct btrfs_path *path;
9167         struct btrfs_trans_handle *trans;
9168         struct btrfs_root *tree_root = fs_info->tree_root;
9169         struct btrfs_root_item *root_item = &root->root_item;
9170         struct walk_control *wc;
9171         struct btrfs_key key;
9172         int err = 0;
9173         int ret;
9174         int level;
9175         bool root_dropped = false;
9176
9177         btrfs_debug(fs_info, "Drop subvolume %llu", root->objectid);
9178
9179         path = btrfs_alloc_path();
9180         if (!path) {
9181                 err = -ENOMEM;
9182                 goto out;
9183         }
9184
9185         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9186         if (!wc) {
9187                 btrfs_free_path(path);
9188                 err = -ENOMEM;
9189                 goto out;
9190         }
9191
9192         trans = btrfs_start_transaction(tree_root, 0);
9193         if (IS_ERR(trans)) {
9194                 err = PTR_ERR(trans);
9195                 goto out_free;
9196         }
9197
9198         if (block_rsv)
9199                 trans->block_rsv = block_rsv;
9200
9201         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
9202                 level = btrfs_header_level(root->node);
9203                 path->nodes[level] = btrfs_lock_root_node(root);
9204                 btrfs_set_lock_blocking(path->nodes[level]);
9205                 path->slots[level] = 0;
9206                 path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9207                 memset(&wc->update_progress, 0,
9208                        sizeof(wc->update_progress));
9209         } else {
9210                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
9211                 memcpy(&wc->update_progress, &key,
9212                        sizeof(wc->update_progress));
9213
9214                 level = root_item->drop_level;
9215                 BUG_ON(level == 0);
9216                 path->lowest_level = level;
9217                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
9218                 path->lowest_level = 0;
9219                 if (ret < 0) {
9220                         err = ret;
9221                         goto out_end_trans;
9222                 }
9223                 WARN_ON(ret > 0);
9224
9225                 /*
9226                  * unlock our path, this is safe because only this
9227                  * function is allowed to delete this snapshot
9228                  */
9229                 btrfs_unlock_up_safe(path, 0);
9230
9231                 level = btrfs_header_level(root->node);
9232                 while (1) {
9233                         btrfs_tree_lock(path->nodes[level]);
9234                         btrfs_set_lock_blocking(path->nodes[level]);
9235                         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9236
9237                         ret = btrfs_lookup_extent_info(trans, fs_info,
9238                                                 path->nodes[level]->start,
9239                                                 level, 1, &wc->refs[level],
9240                                                 &wc->flags[level]);
9241                         if (ret < 0) {
9242                                 err = ret;
9243                                 goto out_end_trans;
9244                         }
9245                         BUG_ON(wc->refs[level] == 0);
9246
9247                         if (level == root_item->drop_level)
9248                                 break;
9249
9250                         btrfs_tree_unlock(path->nodes[level]);
9251                         path->locks[level] = 0;
9252                         WARN_ON(wc->refs[level] != 1);
9253                         level--;
9254                 }
9255         }
9256
9257         wc->level = level;
9258         wc->shared_level = -1;
9259         wc->stage = DROP_REFERENCE;
9260         wc->update_ref = update_ref;
9261         wc->keep_locks = 0;
9262         wc->for_reloc = for_reloc;
9263         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9264
9265         while (1) {
9266
9267                 ret = walk_down_tree(trans, root, path, wc);
9268                 if (ret < 0) {
9269                         err = ret;
9270                         break;
9271                 }
9272
9273                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
9274                 if (ret < 0) {
9275                         err = ret;
9276                         break;
9277                 }
9278
9279                 if (ret > 0) {
9280                         BUG_ON(wc->stage != DROP_REFERENCE);
9281                         break;
9282                 }
9283
9284                 if (wc->stage == DROP_REFERENCE) {
9285                         level = wc->level;
9286                         btrfs_node_key(path->nodes[level],
9287                                        &root_item->drop_progress,
9288                                        path->slots[level]);
9289                         root_item->drop_level = level;
9290                 }
9291
9292                 BUG_ON(wc->level == 0);
9293                 if (btrfs_should_end_transaction(trans) ||
9294                     (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
9295                         ret = btrfs_update_root(trans, tree_root,
9296                                                 &root->root_key,
9297                                                 root_item);
9298                         if (ret) {
9299                                 btrfs_abort_transaction(trans, ret);
9300                                 err = ret;
9301                                 goto out_end_trans;
9302                         }
9303
9304                         btrfs_end_transaction_throttle(trans);
9305                         if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
9306                                 btrfs_debug(fs_info,
9307                                             "drop snapshot early exit");
9308                                 err = -EAGAIN;
9309                                 goto out_free;
9310                         }
9311
9312                         trans = btrfs_start_transaction(tree_root, 0);
9313                         if (IS_ERR(trans)) {
9314                                 err = PTR_ERR(trans);
9315                                 goto out_free;
9316                         }
9317                         if (block_rsv)
9318                                 trans->block_rsv = block_rsv;
9319                 }
9320         }
9321         btrfs_release_path(path);
9322         if (err)
9323                 goto out_end_trans;
9324
9325         ret = btrfs_del_root(trans, fs_info, &root->root_key);
9326         if (ret) {
9327                 btrfs_abort_transaction(trans, ret);
9328                 err = ret;
9329                 goto out_end_trans;
9330         }
9331
9332         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
9333                 ret = btrfs_find_root(tree_root, &root->root_key, path,
9334                                       NULL, NULL);
9335                 if (ret < 0) {
9336                         btrfs_abort_transaction(trans, ret);
9337                         err = ret;
9338                         goto out_end_trans;
9339                 } else if (ret > 0) {
9340                         /* if we fail to delete the orphan item this time
9341                          * around, it'll get picked up the next time.
9342                          *
9343                          * The most common failure here is just -ENOENT.
9344                          */
9345                         btrfs_del_orphan_item(trans, tree_root,
9346                                               root->root_key.objectid);
9347                 }
9348         }
9349
9350         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state)) {
9351                 btrfs_add_dropped_root(trans, root);
9352         } else {
9353                 free_extent_buffer(root->node);
9354                 free_extent_buffer(root->commit_root);
9355                 btrfs_put_fs_root(root);
9356         }
9357         root_dropped = true;
9358 out_end_trans:
9359         btrfs_end_transaction_throttle(trans);
9360 out_free:
9361         kfree(wc);
9362         btrfs_free_path(path);
9363 out:
9364         /*
9365          * So if we need to stop dropping the snapshot for whatever reason we
9366          * need to make sure to add it back to the dead root list so that we
9367          * keep trying to do the work later.  This also cleans up roots if we
9368          * don't have it in the radix (like when we recover after a power fail
9369          * or unmount) so we don't leak memory.
9370          */
9371         if (!for_reloc && root_dropped == false)
9372                 btrfs_add_dead_root(root);
9373         return err;
9374 }
9375
9376 /*
9377  * drop subtree rooted at tree block 'node'.
9378  *
9379  * NOTE: this function will unlock and release tree block 'node'
9380  * only used by relocation code
9381  */
9382 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
9383                         struct btrfs_root *root,
9384                         struct extent_buffer *node,
9385                         struct extent_buffer *parent)
9386 {
9387         struct btrfs_fs_info *fs_info = root->fs_info;
9388         struct btrfs_path *path;
9389         struct walk_control *wc;
9390         int level;
9391         int parent_level;
9392         int ret = 0;
9393         int wret;
9394
9395         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
9396
9397         path = btrfs_alloc_path();
9398         if (!path)
9399                 return -ENOMEM;
9400
9401         wc = kzalloc(sizeof(*wc), GFP_NOFS);
9402         if (!wc) {
9403                 btrfs_free_path(path);
9404                 return -ENOMEM;
9405         }
9406
9407         btrfs_assert_tree_locked(parent);
9408         parent_level = btrfs_header_level(parent);
9409         extent_buffer_get(parent);
9410         path->nodes[parent_level] = parent;
9411         path->slots[parent_level] = btrfs_header_nritems(parent);
9412
9413         btrfs_assert_tree_locked(node);
9414         level = btrfs_header_level(node);
9415         path->nodes[level] = node;
9416         path->slots[level] = 0;
9417         path->locks[level] = BTRFS_WRITE_LOCK_BLOCKING;
9418
9419         wc->refs[parent_level] = 1;
9420         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
9421         wc->level = level;
9422         wc->shared_level = -1;
9423         wc->stage = DROP_REFERENCE;
9424         wc->update_ref = 0;
9425         wc->keep_locks = 1;
9426         wc->for_reloc = 1;
9427         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
9428
9429         while (1) {
9430                 wret = walk_down_tree(trans, root, path, wc);
9431                 if (wret < 0) {
9432                         ret = wret;
9433                         break;
9434                 }
9435
9436                 wret = walk_up_tree(trans, root, path, wc, parent_level);
9437                 if (wret < 0)
9438                         ret = wret;
9439                 if (wret != 0)
9440                         break;
9441         }
9442
9443         kfree(wc);
9444         btrfs_free_path(path);
9445         return ret;
9446 }
9447
9448 static u64 update_block_group_flags(struct btrfs_fs_info *fs_info, u64 flags)
9449 {
9450         u64 num_devices;
9451         u64 stripped;
9452
9453         /*
9454          * if restripe for this chunk_type is on pick target profile and
9455          * return, otherwise do the usual balance
9456          */
9457         stripped = get_restripe_target(fs_info, flags);
9458         if (stripped)
9459                 return extended_to_chunk(stripped);
9460
9461         num_devices = fs_info->fs_devices->rw_devices;
9462
9463         stripped = BTRFS_BLOCK_GROUP_RAID0 |
9464                 BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
9465                 BTRFS_BLOCK_GROUP_RAID1 | BTRFS_BLOCK_GROUP_RAID10;
9466
9467         if (num_devices == 1) {
9468                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9469                 stripped = flags & ~stripped;
9470
9471                 /* turn raid0 into single device chunks */
9472                 if (flags & BTRFS_BLOCK_GROUP_RAID0)
9473                         return stripped;
9474
9475                 /* turn mirroring into duplication */
9476                 if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
9477                              BTRFS_BLOCK_GROUP_RAID10))
9478                         return stripped | BTRFS_BLOCK_GROUP_DUP;
9479         } else {
9480                 /* they already had raid on here, just return */
9481                 if (flags & stripped)
9482                         return flags;
9483
9484                 stripped |= BTRFS_BLOCK_GROUP_DUP;
9485                 stripped = flags & ~stripped;
9486
9487                 /* switch duplicated blocks with raid1 */
9488                 if (flags & BTRFS_BLOCK_GROUP_DUP)
9489                         return stripped | BTRFS_BLOCK_GROUP_RAID1;
9490
9491                 /* this is drive concat, leave it alone */
9492         }
9493
9494         return flags;
9495 }
9496
9497 static int inc_block_group_ro(struct btrfs_block_group_cache *cache, int force)
9498 {
9499         struct btrfs_space_info *sinfo = cache->space_info;
9500         u64 num_bytes;
9501         u64 min_allocable_bytes;
9502         int ret = -ENOSPC;
9503
9504         /*
9505          * We need some metadata space and system metadata space for
9506          * allocating chunks in some corner cases until we force to set
9507          * it to be readonly.
9508          */
9509         if ((sinfo->flags &
9510              (BTRFS_BLOCK_GROUP_SYSTEM | BTRFS_BLOCK_GROUP_METADATA)) &&
9511             !force)
9512                 min_allocable_bytes = SZ_1M;
9513         else
9514                 min_allocable_bytes = 0;
9515
9516         spin_lock(&sinfo->lock);
9517         spin_lock(&cache->lock);
9518
9519         if (cache->ro) {
9520                 cache->ro++;
9521                 ret = 0;
9522                 goto out;
9523         }
9524
9525         num_bytes = cache->key.offset - cache->reserved - cache->pinned -
9526                     cache->bytes_super - btrfs_block_group_used(&cache->item);
9527
9528         if (btrfs_space_info_used(sinfo, true) + num_bytes +
9529             min_allocable_bytes <= sinfo->total_bytes) {
9530                 sinfo->bytes_readonly += num_bytes;
9531                 cache->ro++;
9532                 list_add_tail(&cache->ro_list, &sinfo->ro_bgs);
9533                 ret = 0;
9534         }
9535 out:
9536         spin_unlock(&cache->lock);
9537         spin_unlock(&sinfo->lock);
9538         return ret;
9539 }
9540
9541 int btrfs_inc_block_group_ro(struct btrfs_fs_info *fs_info,
9542                              struct btrfs_block_group_cache *cache)
9543
9544 {
9545         struct btrfs_trans_handle *trans;
9546         u64 alloc_flags;
9547         int ret;
9548
9549 again:
9550         trans = btrfs_join_transaction(fs_info->extent_root);
9551         if (IS_ERR(trans))
9552                 return PTR_ERR(trans);
9553
9554         /*
9555          * we're not allowed to set block groups readonly after the dirty
9556          * block groups cache has started writing.  If it already started,
9557          * back off and let this transaction commit
9558          */
9559         mutex_lock(&fs_info->ro_block_group_mutex);
9560         if (test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &trans->transaction->flags)) {
9561                 u64 transid = trans->transid;
9562
9563                 mutex_unlock(&fs_info->ro_block_group_mutex);
9564                 btrfs_end_transaction(trans);
9565
9566                 ret = btrfs_wait_for_commit(fs_info, transid);
9567                 if (ret)
9568                         return ret;
9569                 goto again;
9570         }
9571
9572         /*
9573          * if we are changing raid levels, try to allocate a corresponding
9574          * block group with the new raid level.
9575          */
9576         alloc_flags = update_block_group_flags(fs_info, cache->flags);
9577         if (alloc_flags != cache->flags) {
9578                 ret = do_chunk_alloc(trans, fs_info, alloc_flags,
9579                                      CHUNK_ALLOC_FORCE);
9580                 /*
9581                  * ENOSPC is allowed here, we may have enough space
9582                  * already allocated at the new raid level to
9583                  * carry on
9584                  */
9585                 if (ret == -ENOSPC)
9586                         ret = 0;
9587                 if (ret < 0)
9588                         goto out;
9589         }
9590
9591         ret = inc_block_group_ro(cache, 0);
9592         if (!ret)
9593                 goto out;
9594         alloc_flags = get_alloc_profile(fs_info, cache->space_info->flags);
9595         ret = do_chunk_alloc(trans, fs_info, alloc_flags,
9596                              CHUNK_ALLOC_FORCE);
9597         if (ret < 0)
9598                 goto out;
9599         ret = inc_block_group_ro(cache, 0);
9600 out:
9601         if (cache->flags & BTRFS_BLOCK_GROUP_SYSTEM) {
9602                 alloc_flags = update_block_group_flags(fs_info, cache->flags);
9603                 mutex_lock(&fs_info->chunk_mutex);
9604                 check_system_chunk(trans, fs_info, alloc_flags);
9605                 mutex_unlock(&fs_info->chunk_mutex);
9606         }
9607         mutex_unlock(&fs_info->ro_block_group_mutex);
9608
9609         btrfs_end_transaction(trans);
9610         return ret;
9611 }
9612
9613 int btrfs_force_chunk_alloc(struct btrfs_trans_handle *trans,
9614                             struct btrfs_fs_info *fs_info, u64 type)
9615 {
9616         u64 alloc_flags = get_alloc_profile(fs_info, type);
9617
9618         return do_chunk_alloc(trans, fs_info, alloc_flags, CHUNK_ALLOC_FORCE);
9619 }
9620
9621 /*
9622  * helper to account the unused space of all the readonly block group in the
9623  * space_info. takes mirrors into account.
9624  */
9625 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
9626 {
9627         struct btrfs_block_group_cache *block_group;
9628         u64 free_bytes = 0;
9629         int factor;
9630
9631         /* It's df, we don't care if it's racy */
9632         if (list_empty(&sinfo->ro_bgs))
9633                 return 0;
9634
9635         spin_lock(&sinfo->lock);
9636         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
9637                 spin_lock(&block_group->lock);
9638
9639                 if (!block_group->ro) {
9640                         spin_unlock(&block_group->lock);
9641                         continue;
9642                 }
9643
9644                 if (block_group->flags & (BTRFS_BLOCK_GROUP_RAID1 |
9645                                           BTRFS_BLOCK_GROUP_RAID10 |
9646                                           BTRFS_BLOCK_GROUP_DUP))
9647                         factor = 2;
9648                 else
9649                         factor = 1;
9650
9651                 free_bytes += (block_group->key.offset -
9652                                btrfs_block_group_used(&block_group->item)) *
9653                                factor;
9654
9655                 spin_unlock(&block_group->lock);
9656         }
9657         spin_unlock(&sinfo->lock);
9658
9659         return free_bytes;
9660 }
9661
9662 void btrfs_dec_block_group_ro(struct btrfs_block_group_cache *cache)
9663 {
9664         struct btrfs_space_info *sinfo = cache->space_info;
9665         u64 num_bytes;
9666
9667         BUG_ON(!cache->ro);
9668
9669         spin_lock(&sinfo->lock);
9670         spin_lock(&cache->lock);
9671         if (!--cache->ro) {
9672                 num_bytes = cache->key.offset - cache->reserved -
9673                             cache->pinned - cache->bytes_super -
9674                             btrfs_block_group_used(&cache->item);
9675                 sinfo->bytes_readonly -= num_bytes;
9676                 list_del_init(&cache->ro_list);
9677         }
9678         spin_unlock(&cache->lock);
9679         spin_unlock(&sinfo->lock);
9680 }
9681
9682 /*
9683  * checks to see if its even possible to relocate this block group.
9684  *
9685  * @return - -1 if it's not a good idea to relocate this block group, 0 if its
9686  * ok to go ahead and try.
9687  */
9688 int btrfs_can_relocate(struct btrfs_fs_info *fs_info, u64 bytenr)
9689 {
9690         struct btrfs_root *root = fs_info->extent_root;
9691         struct btrfs_block_group_cache *block_group;
9692         struct btrfs_space_info *space_info;
9693         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
9694         struct btrfs_device *device;
9695         struct btrfs_trans_handle *trans;
9696         u64 min_free;
9697         u64 dev_min = 1;
9698         u64 dev_nr = 0;
9699         u64 target;
9700         int debug;
9701         int index;
9702         int full = 0;
9703         int ret = 0;
9704
9705         debug = btrfs_test_opt(fs_info, ENOSPC_DEBUG);
9706
9707         block_group = btrfs_lookup_block_group(fs_info, bytenr);
9708
9709         /* odd, couldn't find the block group, leave it alone */
9710         if (!block_group) {
9711                 if (debug)
9712                         btrfs_warn(fs_info,
9713                                    "can't find block group for bytenr %llu",
9714                                    bytenr);
9715                 return -1;
9716         }
9717
9718         min_free = btrfs_block_group_used(&block_group->item);
9719
9720         /* no bytes used, we're good */
9721         if (!min_free)
9722                 goto out;
9723
9724         space_info = block_group->space_info;
9725         spin_lock(&space_info->lock);
9726
9727         full = space_info->full;
9728
9729         /*
9730          * if this is the last block group we have in this space, we can't
9731          * relocate it unless we're able to allocate a new chunk below.
9732          *
9733          * Otherwise, we need to make sure we have room in the space to handle
9734          * all of the extents from this block group.  If we can, we're good
9735          */
9736         if ((space_info->total_bytes != block_group->key.offset) &&
9737             (btrfs_space_info_used(space_info, false) + min_free <
9738              space_info->total_bytes)) {
9739                 spin_unlock(&space_info->lock);
9740                 goto out;
9741         }
9742         spin_unlock(&space_info->lock);
9743
9744         /*
9745          * ok we don't have enough space, but maybe we have free space on our
9746          * devices to allocate new chunks for relocation, so loop through our
9747          * alloc devices and guess if we have enough space.  if this block
9748          * group is going to be restriped, run checks against the target
9749          * profile instead of the current one.
9750          */
9751         ret = -1;
9752
9753         /*
9754          * index:
9755          *      0: raid10
9756          *      1: raid1
9757          *      2: dup
9758          *      3: raid0
9759          *      4: single
9760          */
9761         target = get_restripe_target(fs_info, block_group->flags);
9762         if (target) {
9763                 index = __get_raid_index(extended_to_chunk(target));
9764         } else {
9765                 /*
9766                  * this is just a balance, so if we were marked as full
9767                  * we know there is no space for a new chunk
9768                  */
9769                 if (full) {
9770                         if (debug)
9771                                 btrfs_warn(fs_info,
9772                                            "no space to alloc new chunk for block group %llu",
9773                                            block_group->key.objectid);
9774                         goto out;
9775                 }
9776
9777                 index = get_block_group_index(block_group);
9778         }
9779
9780         if (index == BTRFS_RAID_RAID10) {
9781                 dev_min = 4;
9782                 /* Divide by 2 */
9783                 min_free >>= 1;
9784         } else if (index == BTRFS_RAID_RAID1) {
9785                 dev_min = 2;
9786         } else if (index == BTRFS_RAID_DUP) {
9787                 /* Multiply by 2 */
9788                 min_free <<= 1;
9789         } else if (index == BTRFS_RAID_RAID0) {
9790                 dev_min = fs_devices->rw_devices;
9791                 min_free = div64_u64(min_free, dev_min);
9792         }
9793
9794         /* We need to do this so that we can look at pending chunks */
9795         trans = btrfs_join_transaction(root);
9796         if (IS_ERR(trans)) {
9797                 ret = PTR_ERR(trans);
9798                 goto out;
9799         }
9800
9801         mutex_lock(&fs_info->chunk_mutex);
9802         list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) {
9803                 u64 dev_offset;
9804
9805                 /*
9806                  * check to make sure we can actually find a chunk with enough
9807                  * space to fit our block group in.
9808                  */
9809                 if (device->total_bytes > device->bytes_used + min_free &&
9810                     !device->is_tgtdev_for_dev_replace) {
9811                         ret = find_free_dev_extent(trans, device, min_free,
9812                                                    &dev_offset, NULL);
9813                         if (!ret)
9814                                 dev_nr++;
9815
9816                         if (dev_nr >= dev_min)
9817                                 break;
9818
9819                         ret = -1;
9820                 }
9821         }
9822         if (debug && ret == -1)
9823                 btrfs_warn(fs_info,
9824                            "no space to allocate a new chunk for block group %llu",
9825                            block_group->key.objectid);
9826         mutex_unlock(&fs_info->chunk_mutex);
9827         btrfs_end_transaction(trans);
9828 out:
9829         btrfs_put_block_group(block_group);
9830         return ret;
9831 }
9832
9833 static int find_first_block_group(struct btrfs_fs_info *fs_info,
9834                                   struct btrfs_path *path,
9835                                   struct btrfs_key *key)
9836 {
9837         struct btrfs_root *root = fs_info->extent_root;
9838         int ret = 0;
9839         struct btrfs_key found_key;
9840         struct extent_buffer *leaf;
9841         struct btrfs_block_group_item bg;
9842         u64 flags;
9843         int slot;
9844
9845         ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
9846         if (ret < 0)
9847                 goto out;
9848
9849         while (1) {
9850                 slot = path->slots[0];
9851                 leaf = path->nodes[0];
9852                 if (slot >= btrfs_header_nritems(leaf)) {
9853                         ret = btrfs_next_leaf(root, path);
9854                         if (ret == 0)
9855                                 continue;
9856                         if (ret < 0)
9857                                 goto out;
9858                         break;
9859                 }
9860                 btrfs_item_key_to_cpu(leaf, &found_key, slot);
9861
9862                 if (found_key.objectid >= key->objectid &&
9863                     found_key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
9864                         struct extent_map_tree *em_tree;
9865                         struct extent_map *em;
9866
9867                         em_tree = &root->fs_info->mapping_tree.map_tree;
9868                         read_lock(&em_tree->lock);
9869                         em = lookup_extent_mapping(em_tree, found_key.objectid,
9870                                                    found_key.offset);
9871                         read_unlock(&em_tree->lock);
9872                         if (!em) {
9873                                 btrfs_err(fs_info,
9874                         "logical %llu len %llu found bg but no related chunk",
9875                                           found_key.objectid, found_key.offset);
9876                                 ret = -ENOENT;
9877                         } else if (em->start != found_key.objectid ||
9878                                    em->len != found_key.offset) {
9879                                 btrfs_err(fs_info,
9880                 "block group %llu len %llu mismatch with chunk %llu len %llu",
9881                                           found_key.objectid, found_key.offset,
9882                                           em->start, em->len);
9883                                 ret = -EUCLEAN;
9884                         } else {
9885                                 read_extent_buffer(leaf, &bg,
9886                                         btrfs_item_ptr_offset(leaf, slot),
9887                                         sizeof(bg));
9888                                 flags = btrfs_block_group_flags(&bg) &
9889                                         BTRFS_BLOCK_GROUP_TYPE_MASK;
9890
9891                                 if (flags != (em->map_lookup->type &
9892                                               BTRFS_BLOCK_GROUP_TYPE_MASK)) {
9893                                         btrfs_err(fs_info,
9894 "block group %llu len %llu type flags 0x%llx mismatch with chunk type flags 0x%llx",
9895                                                 found_key.objectid,
9896                                                 found_key.offset, flags,
9897                                                 (BTRFS_BLOCK_GROUP_TYPE_MASK &
9898                                                  em->map_lookup->type));
9899                                         ret = -EUCLEAN;
9900                                 } else {
9901                                         ret = 0;
9902                                 }
9903                         }
9904                         free_extent_map(em);
9905                         goto out;
9906                 }
9907                 path->slots[0]++;
9908         }
9909 out:
9910         return ret;
9911 }
9912
9913 void btrfs_put_block_group_cache(struct btrfs_fs_info *info)
9914 {
9915         struct btrfs_block_group_cache *block_group;
9916         u64 last = 0;
9917
9918         while (1) {
9919                 struct inode *inode;
9920
9921                 block_group = btrfs_lookup_first_block_group(info, last);
9922                 while (block_group) {
9923                         wait_block_group_cache_done(block_group);
9924                         spin_lock(&block_group->lock);
9925                         if (block_group->iref)
9926                                 break;
9927                         spin_unlock(&block_group->lock);
9928                         block_group = next_block_group(info, block_group);
9929                 }
9930                 if (!block_group) {
9931                         if (last == 0)
9932                                 break;
9933                         last = 0;
9934                         continue;
9935                 }
9936
9937                 inode = block_group->inode;
9938                 block_group->iref = 0;
9939                 block_group->inode = NULL;
9940                 spin_unlock(&block_group->lock);
9941                 ASSERT(block_group->io_ctl.inode == NULL);
9942                 iput(inode);
9943                 last = block_group->key.objectid + block_group->key.offset;
9944                 btrfs_put_block_group(block_group);
9945         }
9946 }
9947
9948 /*
9949  * Must be called only after stopping all workers, since we could have block
9950  * group caching kthreads running, and therefore they could race with us if we
9951  * freed the block groups before stopping them.
9952  */
9953 int btrfs_free_block_groups(struct btrfs_fs_info *info)
9954 {
9955         struct btrfs_block_group_cache *block_group;
9956         struct btrfs_space_info *space_info;
9957         struct btrfs_caching_control *caching_ctl;
9958         struct rb_node *n;
9959
9960         down_write(&info->commit_root_sem);
9961         while (!list_empty(&info->caching_block_groups)) {
9962                 caching_ctl = list_entry(info->caching_block_groups.next,
9963                                          struct btrfs_caching_control, list);
9964                 list_del(&caching_ctl->list);
9965                 put_caching_control(caching_ctl);
9966         }
9967         up_write(&info->commit_root_sem);
9968
9969         spin_lock(&info->unused_bgs_lock);
9970         while (!list_empty(&info->unused_bgs)) {
9971                 block_group = list_first_entry(&info->unused_bgs,
9972                                                struct btrfs_block_group_cache,
9973                                                bg_list);
9974                 list_del_init(&block_group->bg_list);
9975                 btrfs_put_block_group(block_group);
9976         }
9977         spin_unlock(&info->unused_bgs_lock);
9978
9979         spin_lock(&info->block_group_cache_lock);
9980         while ((n = rb_last(&info->block_group_cache_tree)) != NULL) {
9981                 block_group = rb_entry(n, struct btrfs_block_group_cache,
9982                                        cache_node);
9983                 rb_erase(&block_group->cache_node,
9984                          &info->block_group_cache_tree);
9985                 RB_CLEAR_NODE(&block_group->cache_node);
9986                 spin_unlock(&info->block_group_cache_lock);
9987
9988                 down_write(&block_group->space_info->groups_sem);
9989                 list_del(&block_group->list);
9990                 up_write(&block_group->space_info->groups_sem);
9991
9992                 /*
9993                  * We haven't cached this block group, which means we could
9994                  * possibly have excluded extents on this block group.
9995                  */
9996                 if (block_group->cached == BTRFS_CACHE_NO ||
9997                     block_group->cached == BTRFS_CACHE_ERROR)
9998                         free_excluded_extents(info, block_group);
9999
10000                 btrfs_remove_free_space_cache(block_group);
10001                 ASSERT(block_group->cached != BTRFS_CACHE_STARTED);
10002                 ASSERT(list_empty(&block_group->dirty_list));
10003                 ASSERT(list_empty(&block_group->io_list));
10004                 ASSERT(list_empty(&block_group->bg_list));
10005                 ASSERT(atomic_read(&block_group->count) == 1);
10006                 btrfs_put_block_group(block_group);
10007
10008                 spin_lock(&info->block_group_cache_lock);
10009         }
10010         spin_unlock(&info->block_group_cache_lock);
10011
10012         /* now that all the block groups are freed, go through and
10013          * free all the space_info structs.  This is only called during
10014          * the final stages of unmount, and so we know nobody is
10015          * using them.  We call synchronize_rcu() once before we start,
10016          * just to be on the safe side.
10017          */
10018         synchronize_rcu();
10019
10020         release_global_block_rsv(info);
10021
10022         while (!list_empty(&info->space_info)) {
10023                 int i;
10024
10025                 space_info = list_entry(info->space_info.next,
10026                                         struct btrfs_space_info,
10027                                         list);
10028
10029                 /*
10030                  * Do not hide this behind enospc_debug, this is actually
10031                  * important and indicates a real bug if this happens.
10032                  */
10033                 if (WARN_ON(space_info->bytes_pinned > 0 ||
10034                             space_info->bytes_reserved > 0 ||
10035                             space_info->bytes_may_use > 0))
10036                         dump_space_info(info, space_info, 0, 0);
10037                 list_del(&space_info->list);
10038                 for (i = 0; i < BTRFS_NR_RAID_TYPES; i++) {
10039                         struct kobject *kobj;
10040                         kobj = space_info->block_group_kobjs[i];
10041                         space_info->block_group_kobjs[i] = NULL;
10042                         if (kobj) {
10043                                 kobject_del(kobj);
10044                                 kobject_put(kobj);
10045                         }
10046                 }
10047                 kobject_del(&space_info->kobj);
10048                 kobject_put(&space_info->kobj);
10049         }
10050         return 0;
10051 }
10052
10053 static void __link_block_group(struct btrfs_space_info *space_info,
10054                                struct btrfs_block_group_cache *cache)
10055 {
10056         int index = get_block_group_index(cache);
10057         bool first = false;
10058
10059         down_write(&space_info->groups_sem);
10060         if (list_empty(&space_info->block_groups[index]))
10061                 first = true;
10062         list_add_tail(&cache->list, &space_info->block_groups[index]);
10063         up_write(&space_info->groups_sem);
10064
10065         if (first) {
10066                 struct raid_kobject *rkobj;
10067                 int ret;
10068
10069                 rkobj = kzalloc(sizeof(*rkobj), GFP_NOFS);
10070                 if (!rkobj)
10071                         goto out_err;
10072                 rkobj->raid_type = index;
10073                 kobject_init(&rkobj->kobj, &btrfs_raid_ktype);
10074                 ret = kobject_add(&rkobj->kobj, &space_info->kobj,
10075                                   "%s", get_raid_name(index));
10076                 if (ret) {
10077                         kobject_put(&rkobj->kobj);
10078                         goto out_err;
10079                 }
10080                 space_info->block_group_kobjs[index] = &rkobj->kobj;
10081         }
10082
10083         return;
10084 out_err:
10085         btrfs_warn(cache->fs_info,
10086                    "failed to add kobject for block cache, ignoring");
10087 }
10088
10089 static struct btrfs_block_group_cache *
10090 btrfs_create_block_group_cache(struct btrfs_fs_info *fs_info,
10091                                u64 start, u64 size)
10092 {
10093         struct btrfs_block_group_cache *cache;
10094
10095         cache = kzalloc(sizeof(*cache), GFP_NOFS);
10096         if (!cache)
10097                 return NULL;
10098
10099         cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
10100                                         GFP_NOFS);
10101         if (!cache->free_space_ctl) {
10102                 kfree(cache);
10103                 return NULL;
10104         }
10105
10106         cache->key.objectid = start;
10107         cache->key.offset = size;
10108         cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10109
10110         cache->fs_info = fs_info;
10111         cache->full_stripe_len = btrfs_full_stripe_len(fs_info, start);
10112         set_free_space_tree_thresholds(cache);
10113
10114         atomic_set(&cache->count, 1);
10115         spin_lock_init(&cache->lock);
10116         init_rwsem(&cache->data_rwsem);
10117         INIT_LIST_HEAD(&cache->list);
10118         INIT_LIST_HEAD(&cache->cluster_list);
10119         INIT_LIST_HEAD(&cache->bg_list);
10120         INIT_LIST_HEAD(&cache->ro_list);
10121         INIT_LIST_HEAD(&cache->dirty_list);
10122         INIT_LIST_HEAD(&cache->io_list);
10123         btrfs_init_free_space_ctl(cache);
10124         atomic_set(&cache->trimming, 0);
10125         mutex_init(&cache->free_space_lock);
10126         btrfs_init_full_stripe_locks_tree(&cache->full_stripe_locks_root);
10127
10128         return cache;
10129 }
10130
10131
10132 /*
10133  * Iterate all chunks and verify that each of them has the corresponding block
10134  * group
10135  */
10136 static int check_chunk_block_group_mappings(struct btrfs_fs_info *fs_info)
10137 {
10138         struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree;
10139         struct extent_map *em;
10140         struct btrfs_block_group_cache *bg;
10141         u64 start = 0;
10142         int ret = 0;
10143
10144         while (1) {
10145                 read_lock(&map_tree->map_tree.lock);
10146                 /*
10147                  * lookup_extent_mapping will return the first extent map
10148                  * intersecting the range, so setting @len to 1 is enough to
10149                  * get the first chunk.
10150                  */
10151                 em = lookup_extent_mapping(&map_tree->map_tree, start, 1);
10152                 read_unlock(&map_tree->map_tree.lock);
10153                 if (!em)
10154                         break;
10155
10156                 bg = btrfs_lookup_block_group(fs_info, em->start);
10157                 if (!bg) {
10158                         btrfs_err(fs_info,
10159         "chunk start=%llu len=%llu doesn't have corresponding block group",
10160                                      em->start, em->len);
10161                         ret = -EUCLEAN;
10162                         free_extent_map(em);
10163                         break;
10164                 }
10165                 if (bg->key.objectid != em->start ||
10166                     bg->key.offset != em->len ||
10167                     (bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK) !=
10168                     (em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK)) {
10169                         btrfs_err(fs_info,
10170 "chunk start=%llu len=%llu flags=0x%llx doesn't match block group start=%llu len=%llu flags=0x%llx",
10171                                 em->start, em->len,
10172                                 em->map_lookup->type & BTRFS_BLOCK_GROUP_TYPE_MASK,
10173                                 bg->key.objectid, bg->key.offset,
10174                                 bg->flags & BTRFS_BLOCK_GROUP_TYPE_MASK);
10175                         ret = -EUCLEAN;
10176                         free_extent_map(em);
10177                         btrfs_put_block_group(bg);
10178                         break;
10179                 }
10180                 start = em->start + em->len;
10181                 free_extent_map(em);
10182                 btrfs_put_block_group(bg);
10183         }
10184         return ret;
10185 }
10186
10187 int btrfs_read_block_groups(struct btrfs_fs_info *info)
10188 {
10189         struct btrfs_path *path;
10190         int ret;
10191         struct btrfs_block_group_cache *cache;
10192         struct btrfs_space_info *space_info;
10193         struct btrfs_key key;
10194         struct btrfs_key found_key;
10195         struct extent_buffer *leaf;
10196         int need_clear = 0;
10197         u64 cache_gen;
10198         u64 feature;
10199         int mixed;
10200
10201         feature = btrfs_super_incompat_flags(info->super_copy);
10202         mixed = !!(feature & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS);
10203
10204         key.objectid = 0;
10205         key.offset = 0;
10206         key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
10207         path = btrfs_alloc_path();
10208         if (!path)
10209                 return -ENOMEM;
10210         path->reada = READA_FORWARD;
10211
10212         cache_gen = btrfs_super_cache_generation(info->super_copy);
10213         if (btrfs_test_opt(info, SPACE_CACHE) &&
10214             btrfs_super_generation(info->super_copy) != cache_gen)
10215                 need_clear = 1;
10216         if (btrfs_test_opt(info, CLEAR_CACHE))
10217                 need_clear = 1;
10218
10219         while (1) {
10220                 ret = find_first_block_group(info, path, &key);
10221                 if (ret > 0)
10222                         break;
10223                 if (ret != 0)
10224                         goto error;
10225
10226                 leaf = path->nodes[0];
10227                 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
10228
10229                 cache = btrfs_create_block_group_cache(info, found_key.objectid,
10230                                                        found_key.offset);
10231                 if (!cache) {
10232                         ret = -ENOMEM;
10233                         goto error;
10234                 }
10235
10236                 if (need_clear) {
10237                         /*
10238                          * When we mount with old space cache, we need to
10239                          * set BTRFS_DC_CLEAR and set dirty flag.
10240                          *
10241                          * a) Setting 'BTRFS_DC_CLEAR' makes sure that we
10242                          *    truncate the old free space cache inode and
10243                          *    setup a new one.
10244                          * b) Setting 'dirty flag' makes sure that we flush
10245                          *    the new space cache info onto disk.
10246                          */
10247                         if (btrfs_test_opt(info, SPACE_CACHE))
10248                                 cache->disk_cache_state = BTRFS_DC_CLEAR;
10249                 }
10250
10251                 read_extent_buffer(leaf, &cache->item,
10252                                    btrfs_item_ptr_offset(leaf, path->slots[0]),
10253                                    sizeof(cache->item));
10254                 cache->flags = btrfs_block_group_flags(&cache->item);
10255                 if (!mixed &&
10256                     ((cache->flags & BTRFS_BLOCK_GROUP_METADATA) &&
10257                     (cache->flags & BTRFS_BLOCK_GROUP_DATA))) {
10258                         btrfs_err(info,
10259 "bg %llu is a mixed block group but filesystem hasn't enabled mixed block groups",
10260                                   cache->key.objectid);
10261                         btrfs_put_block_group(cache);
10262                         ret = -EINVAL;
10263                         goto error;
10264                 }
10265
10266                 key.objectid = found_key.objectid + found_key.offset;
10267                 btrfs_release_path(path);
10268
10269                 /*
10270                  * We need to exclude the super stripes now so that the space
10271                  * info has super bytes accounted for, otherwise we'll think
10272                  * we have more space than we actually do.
10273                  */
10274                 ret = exclude_super_stripes(info, cache);
10275                 if (ret) {
10276                         /*
10277                          * We may have excluded something, so call this just in
10278                          * case.
10279                          */
10280                         free_excluded_extents(info, cache);
10281                         btrfs_put_block_group(cache);
10282                         goto error;
10283                 }
10284
10285                 /*
10286                  * check for two cases, either we are full, and therefore
10287                  * don't need to bother with the caching work since we won't
10288                  * find any space, or we are empty, and we can just add all
10289                  * the space in and be done with it.  This saves us _alot_ of
10290                  * time, particularly in the full case.
10291                  */
10292                 if (found_key.offset == btrfs_block_group_used(&cache->item)) {
10293                         cache->last_byte_to_unpin = (u64)-1;
10294                         cache->cached = BTRFS_CACHE_FINISHED;
10295                         free_excluded_extents(info, cache);
10296                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10297                         cache->last_byte_to_unpin = (u64)-1;
10298                         cache->cached = BTRFS_CACHE_FINISHED;
10299                         add_new_free_space(cache, info,
10300                                            found_key.objectid,
10301                                            found_key.objectid +
10302                                            found_key.offset);
10303                         free_excluded_extents(info, cache);
10304                 }
10305
10306                 ret = btrfs_add_block_group_cache(info, cache);
10307                 if (ret) {
10308                         btrfs_remove_free_space_cache(cache);
10309                         btrfs_put_block_group(cache);
10310                         goto error;
10311                 }
10312
10313                 trace_btrfs_add_block_group(info, cache, 0);
10314                 update_space_info(info, cache->flags, found_key.offset,
10315                                   btrfs_block_group_used(&cache->item),
10316                                   cache->bytes_super, &space_info);
10317
10318                 cache->space_info = space_info;
10319
10320                 __link_block_group(space_info, cache);
10321
10322                 set_avail_alloc_bits(info, cache->flags);
10323                 if (btrfs_chunk_readonly(info, cache->key.objectid)) {
10324                         inc_block_group_ro(cache, 1);
10325                 } else if (btrfs_block_group_used(&cache->item) == 0) {
10326                         spin_lock(&info->unused_bgs_lock);
10327                         /* Should always be true but just in case. */
10328                         if (list_empty(&cache->bg_list)) {
10329                                 btrfs_get_block_group(cache);
10330                                 list_add_tail(&cache->bg_list,
10331                                               &info->unused_bgs);
10332                         }
10333                         spin_unlock(&info->unused_bgs_lock);
10334                 }
10335         }
10336
10337         list_for_each_entry_rcu(space_info, &info->space_info, list) {
10338                 if (!(get_alloc_profile(info, space_info->flags) &
10339                       (BTRFS_BLOCK_GROUP_RAID10 |
10340                        BTRFS_BLOCK_GROUP_RAID1 |
10341                        BTRFS_BLOCK_GROUP_RAID5 |
10342                        BTRFS_BLOCK_GROUP_RAID6 |
10343                        BTRFS_BLOCK_GROUP_DUP)))
10344                         continue;
10345                 /*
10346                  * avoid allocating from un-mirrored block group if there are
10347                  * mirrored block groups.
10348                  */
10349                 list_for_each_entry(cache,
10350                                 &space_info->block_groups[BTRFS_RAID_RAID0],
10351                                 list)
10352                         inc_block_group_ro(cache, 1);
10353                 list_for_each_entry(cache,
10354                                 &space_info->block_groups[BTRFS_RAID_SINGLE],
10355                                 list)
10356                         inc_block_group_ro(cache, 1);
10357         }
10358
10359         init_global_block_rsv(info);
10360         ret = check_chunk_block_group_mappings(info);
10361 error:
10362         btrfs_free_path(path);
10363         return ret;
10364 }
10365
10366 void btrfs_create_pending_block_groups(struct btrfs_trans_handle *trans,
10367                                        struct btrfs_fs_info *fs_info)
10368 {
10369         struct btrfs_block_group_cache *block_group;
10370         struct btrfs_root *extent_root = fs_info->extent_root;
10371         struct btrfs_block_group_item item;
10372         struct btrfs_key key;
10373         int ret = 0;
10374         bool can_flush_pending_bgs = trans->can_flush_pending_bgs;
10375
10376         trans->can_flush_pending_bgs = false;
10377         while (!list_empty(&trans->new_bgs)) {
10378                 block_group = list_first_entry(&trans->new_bgs,
10379                                                struct btrfs_block_group_cache,
10380                                                bg_list);
10381                 if (ret)
10382                         goto next;
10383
10384                 spin_lock(&block_group->lock);
10385                 memcpy(&item, &block_group->item, sizeof(item));
10386                 memcpy(&key, &block_group->key, sizeof(key));
10387                 spin_unlock(&block_group->lock);
10388
10389                 ret = btrfs_insert_item(trans, extent_root, &key, &item,
10390                                         sizeof(item));
10391                 if (ret)
10392                         btrfs_abort_transaction(trans, ret);
10393                 ret = btrfs_finish_chunk_alloc(trans, fs_info, key.objectid,
10394                                                key.offset);
10395                 if (ret)
10396                         btrfs_abort_transaction(trans, ret);
10397                 add_block_group_free_space(trans, fs_info, block_group);
10398                 /* already aborted the transaction if it failed. */
10399 next:
10400                 list_del_init(&block_group->bg_list);
10401         }
10402         trans->can_flush_pending_bgs = can_flush_pending_bgs;
10403 }
10404
10405 int btrfs_make_block_group(struct btrfs_trans_handle *trans,
10406                            struct btrfs_fs_info *fs_info, u64 bytes_used,
10407                            u64 type, u64 chunk_offset, u64 size)
10408 {
10409         struct btrfs_block_group_cache *cache;
10410         int ret;
10411
10412         btrfs_set_log_full_commit(fs_info, trans);
10413
10414         cache = btrfs_create_block_group_cache(fs_info, chunk_offset, size);
10415         if (!cache)
10416                 return -ENOMEM;
10417
10418         btrfs_set_block_group_used(&cache->item, bytes_used);
10419         btrfs_set_block_group_chunk_objectid(&cache->item,
10420                                              BTRFS_FIRST_CHUNK_TREE_OBJECTID);
10421         btrfs_set_block_group_flags(&cache->item, type);
10422
10423         cache->flags = type;
10424         cache->last_byte_to_unpin = (u64)-1;
10425         cache->cached = BTRFS_CACHE_FINISHED;
10426         cache->needs_free_space = 1;
10427         ret = exclude_super_stripes(fs_info, cache);
10428         if (ret) {
10429                 /*
10430                  * We may have excluded something, so call this just in
10431                  * case.
10432                  */
10433                 free_excluded_extents(fs_info, cache);
10434                 btrfs_put_block_group(cache);
10435                 return ret;
10436         }
10437
10438         add_new_free_space(cache, fs_info, chunk_offset, chunk_offset + size);
10439
10440         free_excluded_extents(fs_info, cache);
10441
10442 #ifdef CONFIG_BTRFS_DEBUG
10443         if (btrfs_should_fragment_free_space(cache)) {
10444                 u64 new_bytes_used = size - bytes_used;
10445
10446                 bytes_used += new_bytes_used >> 1;
10447                 fragment_free_space(cache);
10448         }
10449 #endif
10450         /*
10451          * Ensure the corresponding space_info object is created and
10452          * assigned to our block group. We want our bg to be added to the rbtree
10453          * with its ->space_info set.
10454          */
10455         cache->space_info = __find_space_info(fs_info, cache->flags);
10456         if (!cache->space_info) {
10457                 ret = create_space_info(fs_info, cache->flags,
10458                                        &cache->space_info);
10459                 if (ret) {
10460                         btrfs_remove_free_space_cache(cache);
10461                         btrfs_put_block_group(cache);
10462                         return ret;
10463                 }
10464         }
10465
10466         ret = btrfs_add_block_group_cache(fs_info, cache);
10467         if (ret) {
10468                 btrfs_remove_free_space_cache(cache);
10469                 btrfs_put_block_group(cache);
10470                 return ret;
10471         }
10472
10473         /*
10474          * Now that our block group has its ->space_info set and is inserted in
10475          * the rbtree, update the space info's counters.
10476          */
10477         trace_btrfs_add_block_group(fs_info, cache, 1);
10478         update_space_info(fs_info, cache->flags, size, bytes_used,
10479                                 cache->bytes_super, &cache->space_info);
10480         update_global_block_rsv(fs_info);
10481
10482         __link_block_group(cache->space_info, cache);
10483
10484         list_add_tail(&cache->bg_list, &trans->new_bgs);
10485
10486         set_avail_alloc_bits(fs_info, type);
10487         return 0;
10488 }
10489
10490 static void clear_avail_alloc_bits(struct btrfs_fs_info *fs_info, u64 flags)
10491 {
10492         u64 extra_flags = chunk_to_extended(flags) &
10493                                 BTRFS_EXTENDED_PROFILE_MASK;
10494
10495         write_seqlock(&fs_info->profiles_lock);
10496         if (flags & BTRFS_BLOCK_GROUP_DATA)
10497                 fs_info->avail_data_alloc_bits &= ~extra_flags;
10498         if (flags & BTRFS_BLOCK_GROUP_METADATA)
10499                 fs_info->avail_metadata_alloc_bits &= ~extra_flags;
10500         if (flags & BTRFS_BLOCK_GROUP_SYSTEM)
10501                 fs_info->avail_system_alloc_bits &= ~extra_flags;
10502         write_sequnlock(&fs_info->profiles_lock);
10503 }
10504
10505 int btrfs_remove_block_group(struct btrfs_trans_handle *trans,
10506                              struct btrfs_fs_info *fs_info, u64 group_start,
10507                              struct extent_map *em)
10508 {
10509         struct btrfs_root *root = fs_info->extent_root;
10510         struct btrfs_path *path;
10511         struct btrfs_block_group_cache *block_group;
10512         struct btrfs_free_cluster *cluster;
10513         struct btrfs_root *tree_root = fs_info->tree_root;
10514         struct btrfs_key key;
10515         struct inode *inode;
10516         struct kobject *kobj = NULL;
10517         int ret;
10518         int index;
10519         int factor;
10520         struct btrfs_caching_control *caching_ctl = NULL;
10521         bool remove_em;
10522
10523         block_group = btrfs_lookup_block_group(fs_info, group_start);
10524         BUG_ON(!block_group);
10525         BUG_ON(!block_group->ro);
10526
10527         /*
10528          * Free the reserved super bytes from this block group before
10529          * remove it.
10530          */
10531         free_excluded_extents(fs_info, block_group);
10532
10533         memcpy(&key, &block_group->key, sizeof(key));
10534         index = get_block_group_index(block_group);
10535         if (block_group->flags & (BTRFS_BLOCK_GROUP_DUP |
10536                                   BTRFS_BLOCK_GROUP_RAID1 |
10537                                   BTRFS_BLOCK_GROUP_RAID10))
10538                 factor = 2;
10539         else
10540                 factor = 1;
10541
10542         /* make sure this block group isn't part of an allocation cluster */
10543         cluster = &fs_info->data_alloc_cluster;
10544         spin_lock(&cluster->refill_lock);
10545         btrfs_return_cluster_to_free_space(block_group, cluster);
10546         spin_unlock(&cluster->refill_lock);
10547
10548         /*
10549          * make sure this block group isn't part of a metadata
10550          * allocation cluster
10551          */
10552         cluster = &fs_info->meta_alloc_cluster;
10553         spin_lock(&cluster->refill_lock);
10554         btrfs_return_cluster_to_free_space(block_group, cluster);
10555         spin_unlock(&cluster->refill_lock);
10556
10557         path = btrfs_alloc_path();
10558         if (!path) {
10559                 ret = -ENOMEM;
10560                 goto out;
10561         }
10562
10563         /*
10564          * get the inode first so any iput calls done for the io_list
10565          * aren't the final iput (no unlinks allowed now)
10566          */
10567         inode = lookup_free_space_inode(fs_info, block_group, path);
10568
10569         mutex_lock(&trans->transaction->cache_write_mutex);
10570         /*
10571          * make sure our free spache cache IO is done before remove the
10572          * free space inode
10573          */
10574         spin_lock(&trans->transaction->dirty_bgs_lock);
10575         if (!list_empty(&block_group->io_list)) {
10576                 list_del_init(&block_group->io_list);
10577
10578                 WARN_ON(!IS_ERR(inode) && inode != block_group->io_ctl.inode);
10579
10580                 spin_unlock(&trans->transaction->dirty_bgs_lock);
10581                 btrfs_wait_cache_io(trans, block_group, path);
10582                 btrfs_put_block_group(block_group);
10583                 spin_lock(&trans->transaction->dirty_bgs_lock);
10584         }
10585
10586         if (!list_empty(&block_group->dirty_list)) {
10587                 list_del_init(&block_group->dirty_list);
10588                 btrfs_put_block_group(block_group);
10589         }
10590         spin_unlock(&trans->transaction->dirty_bgs_lock);
10591         mutex_unlock(&trans->transaction->cache_write_mutex);
10592
10593         if (!IS_ERR(inode)) {
10594                 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
10595                 if (ret) {
10596                         btrfs_add_delayed_iput(inode);
10597                         goto out;
10598                 }
10599                 clear_nlink(inode);
10600                 /* One for the block groups ref */
10601                 spin_lock(&block_group->lock);
10602                 if (block_group->iref) {
10603                         block_group->iref = 0;
10604                         block_group->inode = NULL;
10605                         spin_unlock(&block_group->lock);
10606                         iput(inode);
10607                 } else {
10608                         spin_unlock(&block_group->lock);
10609                 }
10610                 /* One for our lookup ref */
10611                 btrfs_add_delayed_iput(inode);
10612         }
10613
10614         key.objectid = BTRFS_FREE_SPACE_OBJECTID;
10615         key.offset = block_group->key.objectid;
10616         key.type = 0;
10617
10618         ret = btrfs_search_slot(trans, tree_root, &key, path, -1, 1);
10619         if (ret < 0)
10620                 goto out;
10621         if (ret > 0)
10622                 btrfs_release_path(path);
10623         if (ret == 0) {
10624                 ret = btrfs_del_item(trans, tree_root, path);
10625                 if (ret)
10626                         goto out;
10627                 btrfs_release_path(path);
10628         }
10629
10630         spin_lock(&fs_info->block_group_cache_lock);
10631         rb_erase(&block_group->cache_node,
10632                  &fs_info->block_group_cache_tree);
10633         RB_CLEAR_NODE(&block_group->cache_node);
10634
10635         /* Once for the block groups rbtree */
10636         btrfs_put_block_group(block_group);
10637
10638         if (fs_info->first_logical_byte == block_group->key.objectid)
10639                 fs_info->first_logical_byte = (u64)-1;
10640         spin_unlock(&fs_info->block_group_cache_lock);
10641
10642         down_write(&block_group->space_info->groups_sem);
10643         /*
10644          * we must use list_del_init so people can check to see if they
10645          * are still on the list after taking the semaphore
10646          */
10647         list_del_init(&block_group->list);
10648         if (list_empty(&block_group->space_info->block_groups[index])) {
10649                 kobj = block_group->space_info->block_group_kobjs[index];
10650                 block_group->space_info->block_group_kobjs[index] = NULL;
10651                 clear_avail_alloc_bits(fs_info, block_group->flags);
10652         }
10653         up_write(&block_group->space_info->groups_sem);
10654         if (kobj) {
10655                 kobject_del(kobj);
10656                 kobject_put(kobj);
10657         }
10658
10659         if (block_group->has_caching_ctl)
10660                 caching_ctl = get_caching_control(block_group);
10661         if (block_group->cached == BTRFS_CACHE_STARTED)
10662                 wait_block_group_cache_done(block_group);
10663         if (block_group->has_caching_ctl) {
10664                 down_write(&fs_info->commit_root_sem);
10665                 if (!caching_ctl) {
10666                         struct btrfs_caching_control *ctl;
10667
10668                         list_for_each_entry(ctl,
10669                                     &fs_info->caching_block_groups, list)
10670                                 if (ctl->block_group == block_group) {
10671                                         caching_ctl = ctl;
10672                                         refcount_inc(&caching_ctl->count);
10673                                         break;
10674                                 }
10675                 }
10676                 if (caching_ctl)
10677                         list_del_init(&caching_ctl->list);
10678                 up_write(&fs_info->commit_root_sem);
10679                 if (caching_ctl) {
10680                         /* Once for the caching bgs list and once for us. */
10681                         put_caching_control(caching_ctl);
10682                         put_caching_control(caching_ctl);
10683                 }
10684         }
10685
10686         spin_lock(&trans->transaction->dirty_bgs_lock);
10687         if (!list_empty(&block_group->dirty_list)) {
10688                 WARN_ON(1);
10689         }
10690         if (!list_empty(&block_group->io_list)) {
10691                 WARN_ON(1);
10692         }
10693         spin_unlock(&trans->transaction->dirty_bgs_lock);
10694         btrfs_remove_free_space_cache(block_group);
10695
10696         spin_lock(&block_group->space_info->lock);
10697         list_del_init(&block_group->ro_list);
10698
10699         if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
10700                 WARN_ON(block_group->space_info->total_bytes
10701                         < block_group->key.offset);
10702                 WARN_ON(block_group->space_info->bytes_readonly
10703                         < block_group->key.offset);
10704                 WARN_ON(block_group->space_info->disk_total
10705                         < block_group->key.offset * factor);
10706         }
10707         block_group->space_info->total_bytes -= block_group->key.offset;
10708         block_group->space_info->bytes_readonly -= block_group->key.offset;
10709         block_group->space_info->disk_total -= block_group->key.offset * factor;
10710
10711         spin_unlock(&block_group->space_info->lock);
10712
10713         memcpy(&key, &block_group->key, sizeof(key));
10714
10715         mutex_lock(&fs_info->chunk_mutex);
10716         if (!list_empty(&em->list)) {
10717                 /* We're in the transaction->pending_chunks list. */
10718                 free_extent_map(em);
10719         }
10720         spin_lock(&block_group->lock);
10721         block_group->removed = 1;
10722         /*
10723          * At this point trimming can't start on this block group, because we
10724          * removed the block group from the tree fs_info->block_group_cache_tree
10725          * so no one can't find it anymore and even if someone already got this
10726          * block group before we removed it from the rbtree, they have already
10727          * incremented block_group->trimming - if they didn't, they won't find
10728          * any free space entries because we already removed them all when we
10729          * called btrfs_remove_free_space_cache().
10730          *
10731          * And we must not remove the extent map from the fs_info->mapping_tree
10732          * to prevent the same logical address range and physical device space
10733          * ranges from being reused for a new block group. This is because our
10734          * fs trim operation (btrfs_trim_fs() / btrfs_ioctl_fitrim()) is
10735          * completely transactionless, so while it is trimming a range the
10736          * currently running transaction might finish and a new one start,
10737          * allowing for new block groups to be created that can reuse the same
10738          * physical device locations unless we take this special care.
10739          *
10740          * There may also be an implicit trim operation if the file system
10741          * is mounted with -odiscard. The same protections must remain
10742          * in place until the extents have been discarded completely when
10743          * the transaction commit has completed.
10744          */
10745         remove_em = (atomic_read(&block_group->trimming) == 0);
10746         /*
10747          * Make sure a trimmer task always sees the em in the pinned_chunks list
10748          * if it sees block_group->removed == 1 (needs to lock block_group->lock
10749          * before checking block_group->removed).
10750          */
10751         if (!remove_em) {
10752                 /*
10753                  * Our em might be in trans->transaction->pending_chunks which
10754                  * is protected by fs_info->chunk_mutex ([lock|unlock]_chunks),
10755                  * and so is the fs_info->pinned_chunks list.
10756                  *
10757                  * So at this point we must be holding the chunk_mutex to avoid
10758                  * any races with chunk allocation (more specifically at
10759                  * volumes.c:contains_pending_extent()), to ensure it always
10760                  * sees the em, either in the pending_chunks list or in the
10761                  * pinned_chunks list.
10762                  */
10763                 list_move_tail(&em->list, &fs_info->pinned_chunks);
10764         }
10765         spin_unlock(&block_group->lock);
10766
10767         if (remove_em) {
10768                 struct extent_map_tree *em_tree;
10769
10770                 em_tree = &fs_info->mapping_tree.map_tree;
10771                 write_lock(&em_tree->lock);
10772                 /*
10773                  * The em might be in the pending_chunks list, so make sure the
10774                  * chunk mutex is locked, since remove_extent_mapping() will
10775                  * delete us from that list.
10776                  */
10777                 remove_extent_mapping(em_tree, em);
10778                 write_unlock(&em_tree->lock);
10779                 /* once for the tree */
10780                 free_extent_map(em);
10781         }
10782
10783         mutex_unlock(&fs_info->chunk_mutex);
10784
10785         ret = remove_block_group_free_space(trans, fs_info, block_group);
10786         if (ret)
10787                 goto out;
10788
10789         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
10790         if (ret > 0)
10791                 ret = -EIO;
10792         if (ret < 0)
10793                 goto out;
10794
10795         ret = btrfs_del_item(trans, root, path);
10796
10797 out:
10798         /* Once for the lookup reference */
10799         btrfs_put_block_group(block_group);
10800         btrfs_free_path(path);
10801         return ret;
10802 }
10803
10804 struct btrfs_trans_handle *
10805 btrfs_start_trans_remove_block_group(struct btrfs_fs_info *fs_info,
10806                                      const u64 chunk_offset)
10807 {
10808         struct extent_map_tree *em_tree = &fs_info->mapping_tree.map_tree;
10809         struct extent_map *em;
10810         struct map_lookup *map;
10811         unsigned int num_items;
10812
10813         read_lock(&em_tree->lock);
10814         em = lookup_extent_mapping(em_tree, chunk_offset, 1);
10815         read_unlock(&em_tree->lock);
10816         ASSERT(em && em->start == chunk_offset);
10817
10818         /*
10819          * We need to reserve 3 + N units from the metadata space info in order
10820          * to remove a block group (done at btrfs_remove_chunk() and at
10821          * btrfs_remove_block_group()), which are used for:
10822          *
10823          * 1 unit for adding the free space inode's orphan (located in the tree
10824          * of tree roots).
10825          * 1 unit for deleting the block group item (located in the extent
10826          * tree).
10827          * 1 unit for deleting the free space item (located in tree of tree
10828          * roots).
10829          * N units for deleting N device extent items corresponding to each
10830          * stripe (located in the device tree).
10831          *
10832          * In order to remove a block group we also need to reserve units in the
10833          * system space info in order to update the chunk tree (update one or
10834          * more device items and remove one chunk item), but this is done at
10835          * btrfs_remove_chunk() through a call to check_system_chunk().
10836          */
10837         map = em->map_lookup;
10838         num_items = 3 + map->num_stripes;
10839         free_extent_map(em);
10840
10841         return btrfs_start_transaction_fallback_global_rsv(fs_info->extent_root,
10842                                                            num_items, 1);
10843 }
10844
10845 /*
10846  * Process the unused_bgs list and remove any that don't have any allocated
10847  * space inside of them.
10848  */
10849 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10850 {
10851         struct btrfs_block_group_cache *block_group;
10852         struct btrfs_space_info *space_info;
10853         struct btrfs_trans_handle *trans;
10854         int ret = 0;
10855
10856         if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
10857                 return;
10858
10859         spin_lock(&fs_info->unused_bgs_lock);
10860         while (!list_empty(&fs_info->unused_bgs)) {
10861                 u64 start, end;
10862                 int trimming;
10863
10864                 block_group = list_first_entry(&fs_info->unused_bgs,
10865                                                struct btrfs_block_group_cache,
10866                                                bg_list);
10867                 list_del_init(&block_group->bg_list);
10868
10869                 space_info = block_group->space_info;
10870
10871                 if (ret || btrfs_mixed_space_info(space_info)) {
10872                         btrfs_put_block_group(block_group);
10873                         continue;
10874                 }
10875                 spin_unlock(&fs_info->unused_bgs_lock);
10876
10877                 mutex_lock(&fs_info->delete_unused_bgs_mutex);
10878
10879                 /* Don't want to race with allocators so take the groups_sem */
10880                 down_write(&space_info->groups_sem);
10881                 spin_lock(&block_group->lock);
10882                 if (block_group->reserved || block_group->pinned ||
10883                     btrfs_block_group_used(&block_group->item) ||
10884                     block_group->ro ||
10885                     list_is_singular(&block_group->list)) {
10886                         /*
10887                          * We want to bail if we made new allocations or have
10888                          * outstanding allocations in this block group.  We do
10889                          * the ro check in case balance is currently acting on
10890                          * this block group.
10891                          */
10892                         spin_unlock(&block_group->lock);
10893                         up_write(&space_info->groups_sem);
10894                         goto next;
10895                 }
10896                 spin_unlock(&block_group->lock);
10897
10898                 /* We don't want to force the issue, only flip if it's ok. */
10899                 ret = inc_block_group_ro(block_group, 0);
10900                 up_write(&space_info->groups_sem);
10901                 if (ret < 0) {
10902                         ret = 0;
10903                         goto next;
10904                 }
10905
10906                 /*
10907                  * Want to do this before we do anything else so we can recover
10908                  * properly if we fail to join the transaction.
10909                  */
10910                 trans = btrfs_start_trans_remove_block_group(fs_info,
10911                                                      block_group->key.objectid);
10912                 if (IS_ERR(trans)) {
10913                         btrfs_dec_block_group_ro(block_group);
10914                         ret = PTR_ERR(trans);
10915                         goto next;
10916                 }
10917
10918                 /*
10919                  * We could have pending pinned extents for this block group,
10920                  * just delete them, we don't care about them anymore.
10921                  */
10922                 start = block_group->key.objectid;
10923                 end = start + block_group->key.offset - 1;
10924                 /*
10925                  * Hold the unused_bg_unpin_mutex lock to avoid racing with
10926                  * btrfs_finish_extent_commit(). If we are at transaction N,
10927                  * another task might be running finish_extent_commit() for the
10928                  * previous transaction N - 1, and have seen a range belonging
10929                  * to the block group in freed_extents[] before we were able to
10930                  * clear the whole block group range from freed_extents[]. This
10931                  * means that task can lookup for the block group after we
10932                  * unpinned it from freed_extents[] and removed it, leading to
10933                  * a BUG_ON() at btrfs_unpin_extent_range().
10934                  */
10935                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
10936                 ret = clear_extent_bits(&fs_info->freed_extents[0], start, end,
10937                                   EXTENT_DIRTY);
10938                 if (ret) {
10939                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10940                         btrfs_dec_block_group_ro(block_group);
10941                         goto end_trans;
10942                 }
10943                 ret = clear_extent_bits(&fs_info->freed_extents[1], start, end,
10944                                   EXTENT_DIRTY);
10945                 if (ret) {
10946                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10947                         btrfs_dec_block_group_ro(block_group);
10948                         goto end_trans;
10949                 }
10950                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
10951
10952                 /* Reset pinned so btrfs_put_block_group doesn't complain */
10953                 spin_lock(&space_info->lock);
10954                 spin_lock(&block_group->lock);
10955
10956                 space_info->bytes_pinned -= block_group->pinned;
10957                 space_info->bytes_readonly += block_group->pinned;
10958                 percpu_counter_add(&space_info->total_bytes_pinned,
10959                                    -block_group->pinned);
10960                 block_group->pinned = 0;
10961
10962                 spin_unlock(&block_group->lock);
10963                 spin_unlock(&space_info->lock);
10964
10965                 /* DISCARD can flip during remount */
10966                 trimming = btrfs_test_opt(fs_info, DISCARD);
10967
10968                 /* Implicit trim during transaction commit. */
10969                 if (trimming)
10970                         btrfs_get_block_group_trimming(block_group);
10971
10972                 /*
10973                  * Btrfs_remove_chunk will abort the transaction if things go
10974                  * horribly wrong.
10975                  */
10976                 ret = btrfs_remove_chunk(trans, fs_info,
10977                                          block_group->key.objectid);
10978
10979                 if (ret) {
10980                         if (trimming)
10981                                 btrfs_put_block_group_trimming(block_group);
10982                         goto end_trans;
10983                 }
10984
10985                 /*
10986                  * If we're not mounted with -odiscard, we can just forget
10987                  * about this block group. Otherwise we'll need to wait
10988                  * until transaction commit to do the actual discard.
10989                  */
10990                 if (trimming) {
10991                         spin_lock(&fs_info->unused_bgs_lock);
10992                         /*
10993                          * A concurrent scrub might have added us to the list
10994                          * fs_info->unused_bgs, so use a list_move operation
10995                          * to add the block group to the deleted_bgs list.
10996                          */
10997                         list_move(&block_group->bg_list,
10998                                   &trans->transaction->deleted_bgs);
10999                         spin_unlock(&fs_info->unused_bgs_lock);
11000                         btrfs_get_block_group(block_group);
11001                 }
11002 end_trans:
11003                 btrfs_end_transaction(trans);
11004 next:
11005                 mutex_unlock(&fs_info->delete_unused_bgs_mutex);
11006                 btrfs_put_block_group(block_group);
11007                 spin_lock(&fs_info->unused_bgs_lock);
11008         }
11009         spin_unlock(&fs_info->unused_bgs_lock);
11010 }
11011
11012 int btrfs_init_space_info(struct btrfs_fs_info *fs_info)
11013 {
11014         struct btrfs_space_info *space_info;
11015         struct btrfs_super_block *disk_super;
11016         u64 features;
11017         u64 flags;
11018         int mixed = 0;
11019         int ret;
11020
11021         disk_super = fs_info->super_copy;
11022         if (!btrfs_super_root(disk_super))
11023                 return -EINVAL;
11024
11025         features = btrfs_super_incompat_flags(disk_super);
11026         if (features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS)
11027                 mixed = 1;
11028
11029         flags = BTRFS_BLOCK_GROUP_SYSTEM;
11030         ret = create_space_info(fs_info, flags, &space_info);
11031         if (ret)
11032                 goto out;
11033
11034         if (mixed) {
11035                 flags = BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA;
11036                 ret = create_space_info(fs_info, flags, &space_info);
11037         } else {
11038                 flags = BTRFS_BLOCK_GROUP_METADATA;
11039                 ret = create_space_info(fs_info, flags, &space_info);
11040                 if (ret)
11041                         goto out;
11042
11043                 flags = BTRFS_BLOCK_GROUP_DATA;
11044                 ret = create_space_info(fs_info, flags, &space_info);
11045         }
11046 out:
11047         return ret;
11048 }
11049
11050 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
11051                                    u64 start, u64 end)
11052 {
11053         return unpin_extent_range(fs_info, start, end, false);
11054 }
11055
11056 /*
11057  * It used to be that old block groups would be left around forever.
11058  * Iterating over them would be enough to trim unused space.  Since we
11059  * now automatically remove them, we also need to iterate over unallocated
11060  * space.
11061  *
11062  * We don't want a transaction for this since the discard may take a
11063  * substantial amount of time.  We don't require that a transaction be
11064  * running, but we do need to take a running transaction into account
11065  * to ensure that we're not discarding chunks that were released in
11066  * the current transaction.
11067  *
11068  * Holding the chunks lock will prevent other threads from allocating
11069  * or releasing chunks, but it won't prevent a running transaction
11070  * from committing and releasing the memory that the pending chunks
11071  * list head uses.  For that, we need to take a reference to the
11072  * transaction.
11073  */
11074 static int btrfs_trim_free_extents(struct btrfs_device *device,
11075                                    u64 minlen, u64 *trimmed)
11076 {
11077         u64 start = 0, len = 0;
11078         int ret;
11079
11080         *trimmed = 0;
11081
11082         /* Discard not supported = nothing to do. */
11083         if (!blk_queue_discard(bdev_get_queue(device->bdev)))
11084                 return 0;
11085
11086         /* Not writeable = nothing to do. */
11087         if (!device->writeable)
11088                 return 0;
11089
11090         /* No free space = nothing to do. */
11091         if (device->total_bytes <= device->bytes_used)
11092                 return 0;
11093
11094         ret = 0;
11095
11096         while (1) {
11097                 struct btrfs_fs_info *fs_info = device->fs_info;
11098                 struct btrfs_transaction *trans;
11099                 u64 bytes;
11100
11101                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
11102                 if (ret)
11103                         return ret;
11104
11105                 down_read(&fs_info->commit_root_sem);
11106
11107                 spin_lock(&fs_info->trans_lock);
11108                 trans = fs_info->running_transaction;
11109                 if (trans)
11110                         refcount_inc(&trans->use_count);
11111                 spin_unlock(&fs_info->trans_lock);
11112
11113                 ret = find_free_dev_extent_start(trans, device, minlen, start,
11114                                                  &start, &len);
11115                 if (trans)
11116                         btrfs_put_transaction(trans);
11117
11118                 if (ret) {
11119                         up_read(&fs_info->commit_root_sem);
11120                         mutex_unlock(&fs_info->chunk_mutex);
11121                         if (ret == -ENOSPC)
11122                                 ret = 0;
11123                         break;
11124                 }
11125
11126                 ret = btrfs_issue_discard(device->bdev, start, len, &bytes);
11127                 up_read(&fs_info->commit_root_sem);
11128                 mutex_unlock(&fs_info->chunk_mutex);
11129
11130                 if (ret)
11131                         break;
11132
11133                 start += len;
11134                 *trimmed += bytes;
11135
11136                 if (fatal_signal_pending(current)) {
11137                         ret = -ERESTARTSYS;
11138                         break;
11139                 }
11140
11141                 cond_resched();
11142         }
11143
11144         return ret;
11145 }
11146
11147 /*
11148  * Trim the whole filesystem by:
11149  * 1) trimming the free space in each block group
11150  * 2) trimming the unallocated space on each device
11151  *
11152  * This will also continue trimming even if a block group or device encounters
11153  * an error.  The return value will be the last error, or 0 if nothing bad
11154  * happens.
11155  */
11156 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
11157 {
11158         struct btrfs_block_group_cache *cache = NULL;
11159         struct btrfs_device *device;
11160         struct list_head *devices;
11161         u64 group_trimmed;
11162         u64 start;
11163         u64 end;
11164         u64 trimmed = 0;
11165         u64 bg_failed = 0;
11166         u64 dev_failed = 0;
11167         int bg_ret = 0;
11168         int dev_ret = 0;
11169         int ret = 0;
11170
11171         cache = btrfs_lookup_first_block_group(fs_info, range->start);
11172         for (; cache; cache = next_block_group(fs_info, cache)) {
11173                 if (cache->key.objectid >= (range->start + range->len)) {
11174                         btrfs_put_block_group(cache);
11175                         break;
11176                 }
11177
11178                 start = max(range->start, cache->key.objectid);
11179                 end = min(range->start + range->len,
11180                                 cache->key.objectid + cache->key.offset);
11181
11182                 if (end - start >= range->minlen) {
11183                         if (!block_group_cache_done(cache)) {
11184                                 ret = cache_block_group(cache, 0);
11185                                 if (ret) {
11186                                         bg_failed++;
11187                                         bg_ret = ret;
11188                                         continue;
11189                                 }
11190                                 ret = wait_block_group_cache_done(cache);
11191                                 if (ret) {
11192                                         bg_failed++;
11193                                         bg_ret = ret;
11194                                         continue;
11195                                 }
11196                         }
11197                         ret = btrfs_trim_block_group(cache,
11198                                                      &group_trimmed,
11199                                                      start,
11200                                                      end,
11201                                                      range->minlen);
11202
11203                         trimmed += group_trimmed;
11204                         if (ret) {
11205                                 bg_failed++;
11206                                 bg_ret = ret;
11207                                 continue;
11208                         }
11209                 }
11210         }
11211
11212         if (bg_failed)
11213                 btrfs_warn(fs_info,
11214                         "failed to trim %llu block group(s), last error %d",
11215                         bg_failed, bg_ret);
11216         mutex_lock(&fs_info->fs_devices->device_list_mutex);
11217         devices = &fs_info->fs_devices->devices;
11218         list_for_each_entry(device, devices, dev_list) {
11219                 ret = btrfs_trim_free_extents(device, range->minlen,
11220                                               &group_trimmed);
11221                 if (ret) {
11222                         dev_failed++;
11223                         dev_ret = ret;
11224                         break;
11225                 }
11226
11227                 trimmed += group_trimmed;
11228         }
11229         mutex_unlock(&fs_info->fs_devices->device_list_mutex);
11230
11231         if (dev_failed)
11232                 btrfs_warn(fs_info,
11233                         "failed to trim %llu device(s), last error %d",
11234                         dev_failed, dev_ret);
11235         range->len = trimmed;
11236         if (bg_ret)
11237                 return bg_ret;
11238         return dev_ret;
11239 }
11240
11241 /*
11242  * btrfs_{start,end}_write_no_snapshotting() are similar to
11243  * mnt_{want,drop}_write(), they are used to prevent some tasks from writing
11244  * data into the page cache through nocow before the subvolume is snapshoted,
11245  * but flush the data into disk after the snapshot creation, or to prevent
11246  * operations while snapshotting is ongoing and that cause the snapshot to be
11247  * inconsistent (writes followed by expanding truncates for example).
11248  */
11249 void btrfs_end_write_no_snapshotting(struct btrfs_root *root)
11250 {
11251         percpu_counter_dec(&root->subv_writers->counter);
11252         /*
11253          * Make sure counter is updated before we wake up waiters.
11254          */
11255         smp_mb();
11256         if (waitqueue_active(&root->subv_writers->wait))
11257                 wake_up(&root->subv_writers->wait);
11258 }
11259
11260 int btrfs_start_write_no_snapshotting(struct btrfs_root *root)
11261 {
11262         if (atomic_read(&root->will_be_snapshotted))
11263                 return 0;
11264
11265         percpu_counter_inc(&root->subv_writers->counter);
11266         /*
11267          * Make sure counter is updated before we check for snapshot creation.
11268          */
11269         smp_mb();
11270         if (atomic_read(&root->will_be_snapshotted)) {
11271                 btrfs_end_write_no_snapshotting(root);
11272                 return 0;
11273         }
11274         return 1;
11275 }
11276
11277 static int wait_snapshotting_atomic_t(atomic_t *a)
11278 {
11279         schedule();
11280         return 0;
11281 }
11282
11283 void btrfs_wait_for_snapshot_creation(struct btrfs_root *root)
11284 {
11285         while (true) {
11286                 int ret;
11287
11288                 ret = btrfs_start_write_no_snapshotting(root);
11289                 if (ret)
11290                         break;
11291                 wait_on_atomic_t(&root->will_be_snapshotted,
11292                                  wait_snapshotting_atomic_t,
11293                                  TASK_UNINTERRUPTIBLE);
11294         }
11295 }