fs/btrfs/extent-tree.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/sched.h>
   7 #include <linux/sched/signal.h>
   8 #include <linux/pagemap.h>
   9 #include <linux/writeback.h>
  10 #include <linux/blkdev.h>
  11 #include <linux/sort.h>
  12 #include <linux/rcupdate.h>
  13 #include <linux/kthread.h>
  14 #include <linux/slab.h>
  15 #include <linux/ratelimit.h>
  16 #include <linux/percpu_counter.h>
  17 #include <linux/lockdep.h>
  18 #include <linux/crc32c.h>
  19 #include "misc.h"
  20 #include "tree-log.h"
  21 #include "disk-io.h"
  22 #include "print-tree.h"
  23 #include "volumes.h"
  24 #include "raid56.h"
  25 #include "locking.h"
  26 #include "free-space-cache.h"
  27 #include "free-space-tree.h"
  28 #include "sysfs.h"
  29 #include "qgroup.h"
  30 #include "ref-verify.h"
  31 #include "space-info.h"
  32 #include "block-rsv.h"
  33 #include "delalloc-space.h"
  34 #include "block-group.h"
  35 #include "discard.h"
  36 #include "rcu-string.h"
  37 #include "zoned.h"
  38 #include "dev-replace.h"
  39
  40 #undef SCRAMBLE_DELAYED_REFS
  41
  42
  43 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
  44                                struct btrfs_delayed_ref_node *node, u64 parent,
  45                                u64 root_objectid, u64 owner_objectid,
  46                                u64 owner_offset, int refs_to_drop,
  47                                struct btrfs_delayed_extent_op *extra_op);
  48 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
  49                                     struct extent_buffer *leaf,
  50                                     struct btrfs_extent_item *ei);
  51 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
  52                                       u64 parent, u64 root_objectid,
  53                                       u64 flags, u64 owner, u64 offset,
  54                                       struct btrfs_key *ins, int ref_mod);
  55 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
  56                                      struct btrfs_delayed_ref_node *node,
  57                                      struct btrfs_delayed_extent_op *extent_op);
  58 static int find_next_key(struct btrfs_path *path, int level,
  59                          struct btrfs_key *key);
  60
  61 static int block_group_bits(struct btrfs_block_group *cache, u64 bits)
  62 {
  63         return (cache->flags & bits) == bits;
  64 }
  65
  66 int btrfs_add_excluded_extent(struct btrfs_fs_info *fs_info,
  67                               u64 start, u64 num_bytes)
  68 {
  69         u64 end = start + num_bytes - 1;
  70         set_extent_bits(&fs_info->excluded_extents, start, end,
  71                         EXTENT_UPTODATE);
  72         return 0;
  73 }
  74
  75 void btrfs_free_excluded_extents(struct btrfs_block_group *cache)
  76 {
  77         struct btrfs_fs_info *fs_info = cache->fs_info;
  78         u64 start, end;
  79
  80         start = cache->start;
  81         end = start + cache->length - 1;
  82
  83         clear_extent_bits(&fs_info->excluded_extents, start, end,
  84                           EXTENT_UPTODATE);
  85 }
  86
  87 /* simple helper to search for an existing data extent at a given offset */
  88 int btrfs_lookup_data_extent(struct btrfs_fs_info *fs_info, u64 start, u64 len)
  89 {
  90         struct btrfs_root *root = btrfs_extent_root(fs_info, start);
  91         int ret;
  92         struct btrfs_key key;
  93         struct btrfs_path *path;
  94
  95         path = btrfs_alloc_path();
  96         if (!path)
  97                 return -ENOMEM;
  98
  99         key.objectid = start;
 100         key.offset = len;
 101         key.type = BTRFS_EXTENT_ITEM_KEY;
 102         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 103         btrfs_free_path(path);
 104         return ret;
 105 }
 106
 107 /*
 108  * helper function to lookup reference count and flags of a tree block.
 109  *
 110  * the head node for delayed ref is used to store the sum of all the
 111  * reference count modifications queued up in the rbtree. the head
 112  * node may also store the extent flags to set. This way you can check
 113  * to see what the reference count and extent flags would be if all of
 114  * the delayed refs are not processed.
 115  */
 116 int btrfs_lookup_extent_info(struct btrfs_trans_handle *trans,
 117                              struct btrfs_fs_info *fs_info, u64 bytenr,
 118                              u64 offset, int metadata, u64 *refs, u64 *flags)
 119 {
 120         struct btrfs_root *extent_root;
 121         struct btrfs_delayed_ref_head *head;
 122         struct btrfs_delayed_ref_root *delayed_refs;
 123         struct btrfs_path *path;
 124         struct btrfs_extent_item *ei;
 125         struct extent_buffer *leaf;
 126         struct btrfs_key key;
 127         u32 item_size;
 128         u64 num_refs;
 129         u64 extent_flags;
 130         int ret;
 131
 132         /*
 133          * If we don't have skinny metadata, don't bother doing anything
 134          * different
 135          */
 136         if (metadata && !btrfs_fs_incompat(fs_info, SKINNY_METADATA)) {
 137                 offset = fs_info->nodesize;
 138                 metadata = 0;
 139         }
 140
 141         path = btrfs_alloc_path();
 142         if (!path)
 143                 return -ENOMEM;
 144
 145         if (!trans) {
 146                 path->skip_locking = 1;
 147                 path->search_commit_root = 1;
 148         }
 149
 150 search_again:
 151         key.objectid = bytenr;
 152         key.offset = offset;
 153         if (metadata)
 154                 key.type = BTRFS_METADATA_ITEM_KEY;
 155         else
 156                 key.type = BTRFS_EXTENT_ITEM_KEY;
 157
 158         extent_root = btrfs_extent_root(fs_info, bytenr);
 159         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
 160         if (ret < 0)
 161                 goto out_free;
 162
 163         if (ret > 0 && metadata && key.type == BTRFS_METADATA_ITEM_KEY) {
 164                 if (path->slots[0]) {
 165                         path->slots[0]--;
 166                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 167                                               path->slots[0]);
 168                         if (key.objectid == bytenr &&
 169                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 170                             key.offset == fs_info->nodesize)
 171                                 ret = 0;
 172                 }
 173         }
 174
 175         if (ret == 0) {
 176                 leaf = path->nodes[0];
 177                 item_size = btrfs_item_size(leaf, path->slots[0]);
 178                 if (item_size >= sizeof(*ei)) {
 179                         ei = btrfs_item_ptr(leaf, path->slots[0],
 180                                             struct btrfs_extent_item);
 181                         num_refs = btrfs_extent_refs(leaf, ei);
 182                         extent_flags = btrfs_extent_flags(leaf, ei);
 183                 } else {
 184                         ret = -EINVAL;
 185                         btrfs_print_v0_err(fs_info);
 186                         if (trans)
 187                                 btrfs_abort_transaction(trans, ret);
 188                         else
 189                                 btrfs_handle_fs_error(fs_info, ret, NULL);
 190
 191                         goto out_free;
 192                 }
 193
 194                 BUG_ON(num_refs == 0);
 195         } else {
 196                 num_refs = 0;
 197                 extent_flags = 0;
 198                 ret = 0;
 199         }
 200
 201         if (!trans)
 202                 goto out;
 203
 204         delayed_refs = &trans->transaction->delayed_refs;
 205         spin_lock(&delayed_refs->lock);
 206         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
 207         if (head) {
 208                 if (!mutex_trylock(&head->mutex)) {
 209                         refcount_inc(&head->refs);
 210                         spin_unlock(&delayed_refs->lock);
 211
 212                         btrfs_release_path(path);
 213
 214                         /*
 215                          * Mutex was contended, block until it's released and try
 216                          * again
 217                          */
 218                         mutex_lock(&head->mutex);
 219                         mutex_unlock(&head->mutex);
 220                         btrfs_put_delayed_ref_head(head);
 221                         goto search_again;
 222                 }
 223                 spin_lock(&head->lock);
 224                 if (head->extent_op && head->extent_op->update_flags)
 225                         extent_flags |= head->extent_op->flags_to_set;
 226                 else
 227                         BUG_ON(num_refs == 0);
 228
 229                 num_refs += head->ref_mod;
 230                 spin_unlock(&head->lock);
 231                 mutex_unlock(&head->mutex);
 232         }
 233         spin_unlock(&delayed_refs->lock);
 234 out:
 235         WARN_ON(num_refs == 0);
 236         if (refs)
 237                 *refs = num_refs;
 238         if (flags)
 239                 *flags = extent_flags;
 240 out_free:
 241         btrfs_free_path(path);
 242         return ret;
 243 }
 244
 245 /*
 246  * Back reference rules.  Back refs have three main goals:
 247  *
 248  * 1) differentiate between all holders of references to an extent so that
 249  *    when a reference is dropped we can make sure it was a valid reference
 250  *    before freeing the extent.
 251  *
 252  * 2) Provide enough information to quickly find the holders of an extent
 253  *    if we notice a given block is corrupted or bad.
 254  *
 255  * 3) Make it easy to migrate blocks for FS shrinking or storage pool
 256  *    maintenance.  This is actually the same as #2, but with a slightly
 257  *    different use case.
 258  *
 259  * There are two kinds of back refs. The implicit back refs is optimized
 260  * for pointers in non-shared tree blocks. For a given pointer in a block,
 261  * back refs of this kind provide information about the block's owner tree
 262  * and the pointer's key. These information allow us to find the block by
 263  * b-tree searching. The full back refs is for pointers in tree blocks not
 264  * referenced by their owner trees. The location of tree block is recorded
 265  * in the back refs. Actually the full back refs is generic, and can be
 266  * used in all cases the implicit back refs is used. The major shortcoming
 267  * of the full back refs is its overhead. Every time a tree block gets
 268  * COWed, we have to update back refs entry for all pointers in it.
 269  *
 270  * For a newly allocated tree block, we use implicit back refs for
 271  * pointers in it. This means most tree related operations only involve
 272  * implicit back refs. For a tree block created in old transaction, the
 273  * only way to drop a reference to it is COW it. So we can detect the
 274  * event that tree block loses its owner tree's reference and do the
 275  * back refs conversion.
 276  *
 277  * When a tree block is COWed through a tree, there are four cases:
 278  *
 279  * The reference count of the block is one and the tree is the block's
 280  * owner tree. Nothing to do in this case.
 281  *
 282  * The reference count of the block is one and the tree is not the
 283  * block's owner tree. In this case, full back refs is used for pointers
 284  * in the block. Remove these full back refs, add implicit back refs for
 285  * every pointers in the new block.
 286  *
 287  * The reference count of the block is greater than one and the tree is
 288  * the block's owner tree. In this case, implicit back refs is used for
 289  * pointers in the block. Add full back refs for every pointers in the
 290  * block, increase lower level extents' reference counts. The original
 291  * implicit back refs are entailed to the new block.
 292  *
 293  * The reference count of the block is greater than one and the tree is
 294  * not the block's owner tree. Add implicit back refs for every pointer in
 295  * the new block, increase lower level extents' reference count.
 296  *
 297  * Back Reference Key composing:
 298  *
 299  * The key objectid corresponds to the first byte in the extent,
 300  * The key type is used to differentiate between types of back refs.
 301  * There are different meanings of the key offset for different types
 302  * of back refs.
 303  *
 304  * File extents can be referenced by:
 305  *
 306  * - multiple snapshots, subvolumes, or different generations in one subvol
 307  * - different files inside a single subvolume
 308  * - different offsets inside a file (bookend extents in file.c)
 309  *
 310  * The extent ref structure for the implicit back refs has fields for:
 311  *
 312  * - Objectid of the subvolume root
 313  * - objectid of the file holding the reference
 314  * - original offset in the file
 315  * - how many bookend extents
 316  *
 317  * The key offset for the implicit back refs is hash of the first
 318  * three fields.
 319  *
 320  * The extent ref structure for the full back refs has field for:
 321  *
 322  * - number of pointers in the tree leaf
 323  *
 324  * The key offset for the implicit back refs is the first byte of
 325  * the tree leaf
 326  *
 327  * When a file extent is allocated, The implicit back refs is used.
 328  * the fields are filled in:
 329  *
 330  *     (root_key.objectid, inode objectid, offset in file, 1)
 331  *
 332  * When a file extent is removed file truncation, we find the
 333  * corresponding implicit back refs and check the following fields:
 334  *
 335  *     (btrfs_header_owner(leaf), inode objectid, offset in file)
 336  *
 337  * Btree extents can be referenced by:
 338  *
 339  * - Different subvolumes
 340  *
 341  * Both the implicit back refs and the full back refs for tree blocks
 342  * only consist of key. The key offset for the implicit back refs is
 343  * objectid of block's owner tree. The key offset for the full back refs
 344  * is the first byte of parent block.
 345  *
 346  * When implicit back refs is used, information about the lowest key and
 347  * level of the tree block are required. These information are stored in
 348  * tree block info structure.
 349  */
 350
 351 /*
 352  * is_data == BTRFS_REF_TYPE_BLOCK, tree block type is required,
 353  * is_data == BTRFS_REF_TYPE_DATA, data type is requiried,
 354  * is_data == BTRFS_REF_TYPE_ANY, either type is OK.
 355  */
 356 int btrfs_get_extent_inline_ref_type(const struct extent_buffer *eb,
 357                                      struct btrfs_extent_inline_ref *iref,
 358                                      enum btrfs_inline_ref_type is_data)
 359 {
 360         int type = btrfs_extent_inline_ref_type(eb, iref);
 361         u64 offset = btrfs_extent_inline_ref_offset(eb, iref);
 362
 363         if (type == BTRFS_TREE_BLOCK_REF_KEY ||
 364             type == BTRFS_SHARED_BLOCK_REF_KEY ||
 365             type == BTRFS_SHARED_DATA_REF_KEY ||
 366             type == BTRFS_EXTENT_DATA_REF_KEY) {
 367                 if (is_data == BTRFS_REF_TYPE_BLOCK) {
 368                         if (type == BTRFS_TREE_BLOCK_REF_KEY)
 369                                 return type;
 370                         if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
 371                                 ASSERT(eb->fs_info);
 372                                 /*
 373                                  * Every shared one has parent tree block,
 374                                  * which must be aligned to sector size.
 375                                  */
 376                                 if (offset &&
 377                                     IS_ALIGNED(offset, eb->fs_info->sectorsize))
 378                                         return type;
 379                         }
 380                 } else if (is_data == BTRFS_REF_TYPE_DATA) {
 381                         if (type == BTRFS_EXTENT_DATA_REF_KEY)
 382                                 return type;
 383                         if (type == BTRFS_SHARED_DATA_REF_KEY) {
 384                                 ASSERT(eb->fs_info);
 385                                 /*
 386                                  * Every shared one has parent tree block,
 387                                  * which must be aligned to sector size.
 388                                  */
 389                                 if (offset &&
 390                                     IS_ALIGNED(offset, eb->fs_info->sectorsize))
 391                                         return type;
 392                         }
 393                 } else {
 394                         ASSERT(is_data == BTRFS_REF_TYPE_ANY);
 395                         return type;
 396                 }
 397         }
 398
 399         btrfs_print_leaf((struct extent_buffer *)eb);
 400         btrfs_err(eb->fs_info,
 401                   "eb %llu iref 0x%lx invalid extent inline ref type %d",
 402                   eb->start, (unsigned long)iref, type);
 403         WARN_ON(1);
 404
 405         return BTRFS_REF_TYPE_INVALID;
 406 }
 407
 408 u64 hash_extent_data_ref(u64 root_objectid, u64 owner, u64 offset)
 409 {
 410         u32 high_crc = ~(u32)0;
 411         u32 low_crc = ~(u32)0;
 412         __le64 lenum;
 413
 414         lenum = cpu_to_le64(root_objectid);
 415         high_crc = btrfs_crc32c(high_crc, &lenum, sizeof(lenum));
 416         lenum = cpu_to_le64(owner);
 417         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 418         lenum = cpu_to_le64(offset);
 419         low_crc = btrfs_crc32c(low_crc, &lenum, sizeof(lenum));
 420
 421         return ((u64)high_crc << 31) ^ (u64)low_crc;
 422 }
 423
 424 static u64 hash_extent_data_ref_item(struct extent_buffer *leaf,
 425                                      struct btrfs_extent_data_ref *ref)
 426 {
 427         return hash_extent_data_ref(btrfs_extent_data_ref_root(leaf, ref),
 428                                     btrfs_extent_data_ref_objectid(leaf, ref),
 429                                     btrfs_extent_data_ref_offset(leaf, ref));
 430 }
 431
 432 static int match_extent_data_ref(struct extent_buffer *leaf,
 433                                  struct btrfs_extent_data_ref *ref,
 434                                  u64 root_objectid, u64 owner, u64 offset)
 435 {
 436         if (btrfs_extent_data_ref_root(leaf, ref) != root_objectid ||
 437             btrfs_extent_data_ref_objectid(leaf, ref) != owner ||
 438             btrfs_extent_data_ref_offset(leaf, ref) != offset)
 439                 return 0;
 440         return 1;
 441 }
 442
 443 static noinline int lookup_extent_data_ref(struct btrfs_trans_handle *trans,
 444                                            struct btrfs_path *path,
 445                                            u64 bytenr, u64 parent,
 446                                            u64 root_objectid,
 447                                            u64 owner, u64 offset)
 448 {
 449         struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);
 450         struct btrfs_key key;
 451         struct btrfs_extent_data_ref *ref;
 452         struct extent_buffer *leaf;
 453         u32 nritems;
 454         int ret;
 455         int recow;
 456         int err = -ENOENT;
 457
 458         key.objectid = bytenr;
 459         if (parent) {
 460                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 461                 key.offset = parent;
 462         } else {
 463                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 464                 key.offset = hash_extent_data_ref(root_objectid,
 465                                                   owner, offset);
 466         }
 467 again:
 468         recow = 0;
 469         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 470         if (ret < 0) {
 471                 err = ret;
 472                 goto fail;
 473         }
 474
 475         if (parent) {
 476                 if (!ret)
 477                         return 0;
 478                 goto fail;
 479         }
 480
 481         leaf = path->nodes[0];
 482         nritems = btrfs_header_nritems(leaf);
 483         while (1) {
 484                 if (path->slots[0] >= nritems) {
 485                         ret = btrfs_next_leaf(root, path);
 486                         if (ret < 0)
 487                                 err = ret;
 488                         if (ret)
 489                                 goto fail;
 490
 491                         leaf = path->nodes[0];
 492                         nritems = btrfs_header_nritems(leaf);
 493                         recow = 1;
 494                 }
 495
 496                 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 497                 if (key.objectid != bytenr ||
 498                     key.type != BTRFS_EXTENT_DATA_REF_KEY)
 499                         goto fail;
 500
 501                 ref = btrfs_item_ptr(leaf, path->slots[0],
 502                                      struct btrfs_extent_data_ref);
 503
 504                 if (match_extent_data_ref(leaf, ref, root_objectid,
 505                                           owner, offset)) {
 506                         if (recow) {
 507                                 btrfs_release_path(path);
 508                                 goto again;
 509                         }
 510                         err = 0;
 511                         break;
 512                 }
 513                 path->slots[0]++;
 514         }
 515 fail:
 516         return err;
 517 }
 518
 519 static noinline int insert_extent_data_ref(struct btrfs_trans_handle *trans,
 520                                            struct btrfs_path *path,
 521                                            u64 bytenr, u64 parent,
 522                                            u64 root_objectid, u64 owner,
 523                                            u64 offset, int refs_to_add)
 524 {
 525         struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);
 526         struct btrfs_key key;
 527         struct extent_buffer *leaf;
 528         u32 size;
 529         u32 num_refs;
 530         int ret;
 531
 532         key.objectid = bytenr;
 533         if (parent) {
 534                 key.type = BTRFS_SHARED_DATA_REF_KEY;
 535                 key.offset = parent;
 536                 size = sizeof(struct btrfs_shared_data_ref);
 537         } else {
 538                 key.type = BTRFS_EXTENT_DATA_REF_KEY;
 539                 key.offset = hash_extent_data_ref(root_objectid,
 540                                                   owner, offset);
 541                 size = sizeof(struct btrfs_extent_data_ref);
 542         }
 543
 544         ret = btrfs_insert_empty_item(trans, root, path, &key, size);
 545         if (ret && ret != -EEXIST)
 546                 goto fail;
 547
 548         leaf = path->nodes[0];
 549         if (parent) {
 550                 struct btrfs_shared_data_ref *ref;
 551                 ref = btrfs_item_ptr(leaf, path->slots[0],
 552                                      struct btrfs_shared_data_ref);
 553                 if (ret == 0) {
 554                         btrfs_set_shared_data_ref_count(leaf, ref, refs_to_add);
 555                 } else {
 556                         num_refs = btrfs_shared_data_ref_count(leaf, ref);
 557                         num_refs += refs_to_add;
 558                         btrfs_set_shared_data_ref_count(leaf, ref, num_refs);
 559                 }
 560         } else {
 561                 struct btrfs_extent_data_ref *ref;
 562                 while (ret == -EEXIST) {
 563                         ref = btrfs_item_ptr(leaf, path->slots[0],
 564                                              struct btrfs_extent_data_ref);
 565                         if (match_extent_data_ref(leaf, ref, root_objectid,
 566                                                   owner, offset))
 567                                 break;
 568                         btrfs_release_path(path);
 569                         key.offset++;
 570                         ret = btrfs_insert_empty_item(trans, root, path, &key,
 571                                                       size);
 572                         if (ret && ret != -EEXIST)
 573                                 goto fail;
 574
 575                         leaf = path->nodes[0];
 576                 }
 577                 ref = btrfs_item_ptr(leaf, path->slots[0],
 578                                      struct btrfs_extent_data_ref);
 579                 if (ret == 0) {
 580                         btrfs_set_extent_data_ref_root(leaf, ref,
 581                                                        root_objectid);
 582                         btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
 583                         btrfs_set_extent_data_ref_offset(leaf, ref, offset);
 584                         btrfs_set_extent_data_ref_count(leaf, ref, refs_to_add);
 585                 } else {
 586                         num_refs = btrfs_extent_data_ref_count(leaf, ref);
 587                         num_refs += refs_to_add;
 588                         btrfs_set_extent_data_ref_count(leaf, ref, num_refs);
 589                 }
 590         }
 591         btrfs_mark_buffer_dirty(leaf);
 592         ret = 0;
 593 fail:
 594         btrfs_release_path(path);
 595         return ret;
 596 }
 597
 598 static noinline int remove_extent_data_ref(struct btrfs_trans_handle *trans,
 599                                            struct btrfs_root *root,
 600                                            struct btrfs_path *path,
 601                                            int refs_to_drop)
 602 {
 603         struct btrfs_key key;
 604         struct btrfs_extent_data_ref *ref1 = NULL;
 605         struct btrfs_shared_data_ref *ref2 = NULL;
 606         struct extent_buffer *leaf;
 607         u32 num_refs = 0;
 608         int ret = 0;
 609
 610         leaf = path->nodes[0];
 611         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 612
 613         if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 614                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
 615                                       struct btrfs_extent_data_ref);
 616                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 617         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 618                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
 619                                       struct btrfs_shared_data_ref);
 620                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 621         } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
 622                 btrfs_print_v0_err(trans->fs_info);
 623                 btrfs_abort_transaction(trans, -EINVAL);
 624                 return -EINVAL;
 625         } else {
 626                 BUG();
 627         }
 628
 629         BUG_ON(num_refs < refs_to_drop);
 630         num_refs -= refs_to_drop;
 631
 632         if (num_refs == 0) {
 633                 ret = btrfs_del_item(trans, root, path);
 634         } else {
 635                 if (key.type == BTRFS_EXTENT_DATA_REF_KEY)
 636                         btrfs_set_extent_data_ref_count(leaf, ref1, num_refs);
 637                 else if (key.type == BTRFS_SHARED_DATA_REF_KEY)
 638                         btrfs_set_shared_data_ref_count(leaf, ref2, num_refs);
 639                 btrfs_mark_buffer_dirty(leaf);
 640         }
 641         return ret;
 642 }
 643
 644 static noinline u32 extent_data_ref_count(struct btrfs_path *path,
 645                                           struct btrfs_extent_inline_ref *iref)
 646 {
 647         struct btrfs_key key;
 648         struct extent_buffer *leaf;
 649         struct btrfs_extent_data_ref *ref1;
 650         struct btrfs_shared_data_ref *ref2;
 651         u32 num_refs = 0;
 652         int type;
 653
 654         leaf = path->nodes[0];
 655         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
 656
 657         BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
 658         if (iref) {
 659                 /*
 660                  * If type is invalid, we should have bailed out earlier than
 661                  * this call.
 662                  */
 663                 type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
 664                 ASSERT(type != BTRFS_REF_TYPE_INVALID);
 665                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
 666                         ref1 = (struct btrfs_extent_data_ref *)(&iref->offset);
 667                         num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 668                 } else {
 669                         ref2 = (struct btrfs_shared_data_ref *)(iref + 1);
 670                         num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 671                 }
 672         } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
 673                 ref1 = btrfs_item_ptr(leaf, path->slots[0],
 674                                       struct btrfs_extent_data_ref);
 675                 num_refs = btrfs_extent_data_ref_count(leaf, ref1);
 676         } else if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
 677                 ref2 = btrfs_item_ptr(leaf, path->slots[0],
 678                                       struct btrfs_shared_data_ref);
 679                 num_refs = btrfs_shared_data_ref_count(leaf, ref2);
 680         } else {
 681                 WARN_ON(1);
 682         }
 683         return num_refs;
 684 }
 685
 686 static noinline int lookup_tree_block_ref(struct btrfs_trans_handle *trans,
 687                                           struct btrfs_path *path,
 688                                           u64 bytenr, u64 parent,
 689                                           u64 root_objectid)
 690 {
 691         struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);
 692         struct btrfs_key key;
 693         int ret;
 694
 695         key.objectid = bytenr;
 696         if (parent) {
 697                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 698                 key.offset = parent;
 699         } else {
 700                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
 701                 key.offset = root_objectid;
 702         }
 703
 704         ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
 705         if (ret > 0)
 706                 ret = -ENOENT;
 707         return ret;
 708 }
 709
 710 static noinline int insert_tree_block_ref(struct btrfs_trans_handle *trans,
 711                                           struct btrfs_path *path,
 712                                           u64 bytenr, u64 parent,
 713                                           u64 root_objectid)
 714 {
 715         struct btrfs_root *root = btrfs_extent_root(trans->fs_info, bytenr);
 716         struct btrfs_key key;
 717         int ret;
 718
 719         key.objectid = bytenr;
 720         if (parent) {
 721                 key.type = BTRFS_SHARED_BLOCK_REF_KEY;
 722                 key.offset = parent;
 723         } else {
 724                 key.type = BTRFS_TREE_BLOCK_REF_KEY;
 725                 key.offset = root_objectid;
 726         }
 727
 728         ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
 729         btrfs_release_path(path);
 730         return ret;
 731 }
 732
 733 static inline int extent_ref_type(u64 parent, u64 owner)
 734 {
 735         int type;
 736         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
 737                 if (parent > 0)
 738                         type = BTRFS_SHARED_BLOCK_REF_KEY;
 739                 else
 740                         type = BTRFS_TREE_BLOCK_REF_KEY;
 741         } else {
 742                 if (parent > 0)
 743                         type = BTRFS_SHARED_DATA_REF_KEY;
 744                 else
 745                         type = BTRFS_EXTENT_DATA_REF_KEY;
 746         }
 747         return type;
 748 }
 749
 750 static int find_next_key(struct btrfs_path *path, int level,
 751                          struct btrfs_key *key)
 752
 753 {
 754         for (; level < BTRFS_MAX_LEVEL; level++) {
 755                 if (!path->nodes[level])
 756                         break;
 757                 if (path->slots[level] + 1 >=
 758                     btrfs_header_nritems(path->nodes[level]))
 759                         continue;
 760                 if (level == 0)
 761                         btrfs_item_key_to_cpu(path->nodes[level], key,
 762                                               path->slots[level] + 1);
 763                 else
 764                         btrfs_node_key_to_cpu(path->nodes[level], key,
 765                                               path->slots[level] + 1);
 766                 return 0;
 767         }
 768         return 1;
 769 }
 770
 771 /*
 772  * look for inline back ref. if back ref is found, *ref_ret is set
 773  * to the address of inline back ref, and 0 is returned.
 774  *
 775  * if back ref isn't found, *ref_ret is set to the address where it
 776  * should be inserted, and -ENOENT is returned.
 777  *
 778  * if insert is true and there are too many inline back refs, the path
 779  * points to the extent item, and -EAGAIN is returned.
 780  *
 781  * NOTE: inline back refs are ordered in the same way that back ref
 782  *       items in the tree are ordered.
 783  */
 784 static noinline_for_stack
 785 int lookup_inline_extent_backref(struct btrfs_trans_handle *trans,
 786                                  struct btrfs_path *path,
 787                                  struct btrfs_extent_inline_ref **ref_ret,
 788                                  u64 bytenr, u64 num_bytes,
 789                                  u64 parent, u64 root_objectid,
 790                                  u64 owner, u64 offset, int insert)
 791 {
 792         struct btrfs_fs_info *fs_info = trans->fs_info;
 793         struct btrfs_root *root = btrfs_extent_root(fs_info, bytenr);
 794         struct btrfs_key key;
 795         struct extent_buffer *leaf;
 796         struct btrfs_extent_item *ei;
 797         struct btrfs_extent_inline_ref *iref;
 798         u64 flags;
 799         u64 item_size;
 800         unsigned long ptr;
 801         unsigned long end;
 802         int extra_size;
 803         int type;
 804         int want;
 805         int ret;
 806         int err = 0;
 807         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
 808         int needed;
 809
 810         key.objectid = bytenr;
 811         key.type = BTRFS_EXTENT_ITEM_KEY;
 812         key.offset = num_bytes;
 813
 814         want = extent_ref_type(parent, owner);
 815         if (insert) {
 816                 extra_size = btrfs_extent_inline_ref_size(want);
 817                 path->search_for_extension = 1;
 818                 path->keep_locks = 1;
 819         } else
 820                 extra_size = -1;
 821
 822         /*
 823          * Owner is our level, so we can just add one to get the level for the
 824          * block we are interested in.
 825          */
 826         if (skinny_metadata && owner < BTRFS_FIRST_FREE_OBJECTID) {
 827                 key.type = BTRFS_METADATA_ITEM_KEY;
 828                 key.offset = owner;
 829         }
 830
 831 again:
 832         ret = btrfs_search_slot(trans, root, &key, path, extra_size, 1);
 833         if (ret < 0) {
 834                 err = ret;
 835                 goto out;
 836         }
 837
 838         /*
 839          * We may be a newly converted file system which still has the old fat
 840          * extent entries for metadata, so try and see if we have one of those.
 841          */
 842         if (ret > 0 && skinny_metadata) {
 843                 skinny_metadata = false;
 844                 if (path->slots[0]) {
 845                         path->slots[0]--;
 846                         btrfs_item_key_to_cpu(path->nodes[0], &key,
 847                                               path->slots[0]);
 848                         if (key.objectid == bytenr &&
 849                             key.type == BTRFS_EXTENT_ITEM_KEY &&
 850                             key.offset == num_bytes)
 851                                 ret = 0;
 852                 }
 853                 if (ret) {
 854                         key.objectid = bytenr;
 855                         key.type = BTRFS_EXTENT_ITEM_KEY;
 856                         key.offset = num_bytes;
 857                         btrfs_release_path(path);
 858                         goto again;
 859                 }
 860         }
 861
 862         if (ret && !insert) {
 863                 err = -ENOENT;
 864                 goto out;
 865         } else if (WARN_ON(ret)) {
 866                 err = -EIO;
 867                 goto out;
 868         }
 869
 870         leaf = path->nodes[0];
 871         item_size = btrfs_item_size(leaf, path->slots[0]);
 872         if (unlikely(item_size < sizeof(*ei))) {
 873                 err = -EINVAL;
 874                 btrfs_print_v0_err(fs_info);
 875                 btrfs_abort_transaction(trans, err);
 876                 goto out;
 877         }
 878
 879         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
 880         flags = btrfs_extent_flags(leaf, ei);
 881
 882         ptr = (unsigned long)(ei + 1);
 883         end = (unsigned long)ei + item_size;
 884
 885         if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK && !skinny_metadata) {
 886                 ptr += sizeof(struct btrfs_tree_block_info);
 887                 BUG_ON(ptr > end);
 888         }
 889
 890         if (owner >= BTRFS_FIRST_FREE_OBJECTID)
 891                 needed = BTRFS_REF_TYPE_DATA;
 892         else
 893                 needed = BTRFS_REF_TYPE_BLOCK;
 894
 895         err = -ENOENT;
 896         while (1) {
 897                 if (ptr >= end) {
 898                         if (ptr > end) {
 899                                 err = -EUCLEAN;
 900                                 btrfs_print_leaf(path->nodes[0]);
 901                                 btrfs_crit(fs_info,
 902 "overrun extent record at slot %d while looking for inline extent for root %llu owner %llu offset %llu parent %llu",
 903                                         path->slots[0], root_objectid, owner, offset, parent);
 904                         }
 905                         break;
 906                 }
 907                 iref = (struct btrfs_extent_inline_ref *)ptr;
 908                 type = btrfs_get_extent_inline_ref_type(leaf, iref, needed);
 909                 if (type == BTRFS_REF_TYPE_INVALID) {
 910                         err = -EUCLEAN;
 911                         goto out;
 912                 }
 913
 914                 if (want < type)
 915                         break;
 916                 if (want > type) {
 917                         ptr += btrfs_extent_inline_ref_size(type);
 918                         continue;
 919                 }
 920
 921                 if (type == BTRFS_EXTENT_DATA_REF_KEY) {
 922                         struct btrfs_extent_data_ref *dref;
 923                         dref = (struct btrfs_extent_data_ref *)(&iref->offset);
 924                         if (match_extent_data_ref(leaf, dref, root_objectid,
 925                                                   owner, offset)) {
 926                                 err = 0;
 927                                 break;
 928                         }
 929                         if (hash_extent_data_ref_item(leaf, dref) <
 930                             hash_extent_data_ref(root_objectid, owner, offset))
 931                                 break;
 932                 } else {
 933                         u64 ref_offset;
 934                         ref_offset = btrfs_extent_inline_ref_offset(leaf, iref);
 935                         if (parent > 0) {
 936                                 if (parent == ref_offset) {
 937                                         err = 0;
 938                                         break;
 939                                 }
 940                                 if (ref_offset < parent)
 941                                         break;
 942                         } else {
 943                                 if (root_objectid == ref_offset) {
 944                                         err = 0;
 945                                         break;
 946                                 }
 947                                 if (ref_offset < root_objectid)
 948                                         break;
 949                         }
 950                 }
 951                 ptr += btrfs_extent_inline_ref_size(type);
 952         }
 953         if (err == -ENOENT && insert) {
 954                 if (item_size + extra_size >=
 955                     BTRFS_MAX_EXTENT_ITEM_SIZE(root)) {
 956                         err = -EAGAIN;
 957                         goto out;
 958                 }
 959                 /*
 960                  * To add new inline back ref, we have to make sure
 961                  * there is no corresponding back ref item.
 962                  * For simplicity, we just do not add new inline back
 963                  * ref if there is any kind of item for this block
 964                  */
 965                 if (find_next_key(path, 0, &key) == 0 &&
 966                     key.objectid == bytenr &&
 967                     key.type < BTRFS_BLOCK_GROUP_ITEM_KEY) {
 968                         err = -EAGAIN;
 969                         goto out;
 970                 }
 971         }
 972         *ref_ret = (struct btrfs_extent_inline_ref *)ptr;
 973 out:
 974         if (insert) {
 975                 path->keep_locks = 0;
 976                 path->search_for_extension = 0;
 977                 btrfs_unlock_up_safe(path, 1);
 978         }
 979         return err;
 980 }
 981
 982 /*
 983  * helper to add new inline back ref
 984  */
 985 static noinline_for_stack
 986 void setup_inline_extent_backref(struct btrfs_fs_info *fs_info,
 987                                  struct btrfs_path *path,
 988                                  struct btrfs_extent_inline_ref *iref,
 989                                  u64 parent, u64 root_objectid,
 990                                  u64 owner, u64 offset, int refs_to_add,
 991                                  struct btrfs_delayed_extent_op *extent_op)
 992 {
 993         struct extent_buffer *leaf;
 994         struct btrfs_extent_item *ei;
 995         unsigned long ptr;
 996         unsigned long end;
 997         unsigned long item_offset;
 998         u64 refs;
 999         int size;
1000         int type;
1001
1002         leaf = path->nodes[0];
1003         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1004         item_offset = (unsigned long)iref - (unsigned long)ei;
1005
1006         type = extent_ref_type(parent, owner);
1007         size = btrfs_extent_inline_ref_size(type);
1008
1009         btrfs_extend_item(path, size);
1010
1011         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1012         refs = btrfs_extent_refs(leaf, ei);
1013         refs += refs_to_add;
1014         btrfs_set_extent_refs(leaf, ei, refs);
1015         if (extent_op)
1016                 __run_delayed_extent_op(extent_op, leaf, ei);
1017
1018         ptr = (unsigned long)ei + item_offset;
1019         end = (unsigned long)ei + btrfs_item_size(leaf, path->slots[0]);
1020         if (ptr < end - size)
1021                 memmove_extent_buffer(leaf, ptr + size, ptr,
1022                                       end - size - ptr);
1023
1024         iref = (struct btrfs_extent_inline_ref *)ptr;
1025         btrfs_set_extent_inline_ref_type(leaf, iref, type);
1026         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1027                 struct btrfs_extent_data_ref *dref;
1028                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1029                 btrfs_set_extent_data_ref_root(leaf, dref, root_objectid);
1030                 btrfs_set_extent_data_ref_objectid(leaf, dref, owner);
1031                 btrfs_set_extent_data_ref_offset(leaf, dref, offset);
1032                 btrfs_set_extent_data_ref_count(leaf, dref, refs_to_add);
1033         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1034                 struct btrfs_shared_data_ref *sref;
1035                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1036                 btrfs_set_shared_data_ref_count(leaf, sref, refs_to_add);
1037                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1038         } else if (type == BTRFS_SHARED_BLOCK_REF_KEY) {
1039                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
1040         } else {
1041                 btrfs_set_extent_inline_ref_offset(leaf, iref, root_objectid);
1042         }
1043         btrfs_mark_buffer_dirty(leaf);
1044 }
1045
1046 static int lookup_extent_backref(struct btrfs_trans_handle *trans,
1047                                  struct btrfs_path *path,
1048                                  struct btrfs_extent_inline_ref **ref_ret,
1049                                  u64 bytenr, u64 num_bytes, u64 parent,
1050                                  u64 root_objectid, u64 owner, u64 offset)
1051 {
1052         int ret;
1053
1054         ret = lookup_inline_extent_backref(trans, path, ref_ret, bytenr,
1055                                            num_bytes, parent, root_objectid,
1056                                            owner, offset, 0);
1057         if (ret != -ENOENT)
1058                 return ret;
1059
1060         btrfs_release_path(path);
1061         *ref_ret = NULL;
1062
1063         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1064                 ret = lookup_tree_block_ref(trans, path, bytenr, parent,
1065                                             root_objectid);
1066         } else {
1067                 ret = lookup_extent_data_ref(trans, path, bytenr, parent,
1068                                              root_objectid, owner, offset);
1069         }
1070         return ret;
1071 }
1072
1073 /*
1074  * helper to update/remove inline back ref
1075  */
1076 static noinline_for_stack
1077 void update_inline_extent_backref(struct btrfs_path *path,
1078                                   struct btrfs_extent_inline_ref *iref,
1079                                   int refs_to_mod,
1080                                   struct btrfs_delayed_extent_op *extent_op)
1081 {
1082         struct extent_buffer *leaf = path->nodes[0];
1083         struct btrfs_extent_item *ei;
1084         struct btrfs_extent_data_ref *dref = NULL;
1085         struct btrfs_shared_data_ref *sref = NULL;
1086         unsigned long ptr;
1087         unsigned long end;
1088         u32 item_size;
1089         int size;
1090         int type;
1091         u64 refs;
1092
1093         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1094         refs = btrfs_extent_refs(leaf, ei);
1095         WARN_ON(refs_to_mod < 0 && refs + refs_to_mod <= 0);
1096         refs += refs_to_mod;
1097         btrfs_set_extent_refs(leaf, ei, refs);
1098         if (extent_op)
1099                 __run_delayed_extent_op(extent_op, leaf, ei);
1100
1101         /*
1102          * If type is invalid, we should have bailed out after
1103          * lookup_inline_extent_backref().
1104          */
1105         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_ANY);
1106         ASSERT(type != BTRFS_REF_TYPE_INVALID);
1107
1108         if (type == BTRFS_EXTENT_DATA_REF_KEY) {
1109                 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
1110                 refs = btrfs_extent_data_ref_count(leaf, dref);
1111         } else if (type == BTRFS_SHARED_DATA_REF_KEY) {
1112                 sref = (struct btrfs_shared_data_ref *)(iref + 1);
1113                 refs = btrfs_shared_data_ref_count(leaf, sref);
1114         } else {
1115                 refs = 1;
1116                 BUG_ON(refs_to_mod != -1);
1117         }
1118
1119         BUG_ON(refs_to_mod < 0 && refs < -refs_to_mod);
1120         refs += refs_to_mod;
1121
1122         if (refs > 0) {
1123                 if (type == BTRFS_EXTENT_DATA_REF_KEY)
1124                         btrfs_set_extent_data_ref_count(leaf, dref, refs);
1125                 else
1126                         btrfs_set_shared_data_ref_count(leaf, sref, refs);
1127         } else {
1128                 size =  btrfs_extent_inline_ref_size(type);
1129                 item_size = btrfs_item_size(leaf, path->slots[0]);
1130                 ptr = (unsigned long)iref;
1131                 end = (unsigned long)ei + item_size;
1132                 if (ptr + size < end)
1133                         memmove_extent_buffer(leaf, ptr, ptr + size,
1134                                               end - ptr - size);
1135                 item_size -= size;
1136                 btrfs_truncate_item(path, item_size, 1);
1137         }
1138         btrfs_mark_buffer_dirty(leaf);
1139 }
1140
1141 static noinline_for_stack
1142 int insert_inline_extent_backref(struct btrfs_trans_handle *trans,
1143                                  struct btrfs_path *path,
1144                                  u64 bytenr, u64 num_bytes, u64 parent,
1145                                  u64 root_objectid, u64 owner,
1146                                  u64 offset, int refs_to_add,
1147                                  struct btrfs_delayed_extent_op *extent_op)
1148 {
1149         struct btrfs_extent_inline_ref *iref;
1150         int ret;
1151
1152         ret = lookup_inline_extent_backref(trans, path, &iref, bytenr,
1153                                            num_bytes, parent, root_objectid,
1154                                            owner, offset, 1);
1155         if (ret == 0) {
1156                 /*
1157                  * We're adding refs to a tree block we already own, this
1158                  * should not happen at all.
1159                  */
1160                 if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1161                         btrfs_crit(trans->fs_info,
1162 "adding refs to an existing tree ref, bytenr %llu num_bytes %llu root_objectid %llu",
1163                                    bytenr, num_bytes, root_objectid);
1164                         if (IS_ENABLED(CONFIG_BTRFS_DEBUG)) {
1165                                 WARN_ON(1);
1166                                 btrfs_crit(trans->fs_info,
1167                         "path->slots[0]=%d path->nodes[0]:", path->slots[0]);
1168                                 btrfs_print_leaf(path->nodes[0]);
1169                         }
1170                         return -EUCLEAN;
1171                 }
1172                 update_inline_extent_backref(path, iref, refs_to_add, extent_op);
1173         } else if (ret == -ENOENT) {
1174                 setup_inline_extent_backref(trans->fs_info, path, iref, parent,
1175                                             root_objectid, owner, offset,
1176                                             refs_to_add, extent_op);
1177                 ret = 0;
1178         }
1179         return ret;
1180 }
1181
1182 static int remove_extent_backref(struct btrfs_trans_handle *trans,
1183                                  struct btrfs_root *root,
1184                                  struct btrfs_path *path,
1185                                  struct btrfs_extent_inline_ref *iref,
1186                                  int refs_to_drop, int is_data)
1187 {
1188         int ret = 0;
1189
1190         BUG_ON(!is_data && refs_to_drop != 1);
1191         if (iref)
1192                 update_inline_extent_backref(path, iref, -refs_to_drop, NULL);
1193         else if (is_data)
1194                 ret = remove_extent_data_ref(trans, root, path, refs_to_drop);
1195         else
1196                 ret = btrfs_del_item(trans, root, path);
1197         return ret;
1198 }
1199
1200 static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
1201                                u64 *discarded_bytes)
1202 {
1203         int j, ret = 0;
1204         u64 bytes_left, end;
1205         u64 aligned_start = ALIGN(start, 1 << 9);
1206
1207         if (WARN_ON(start != aligned_start)) {
1208                 len -= aligned_start - start;
1209                 len = round_down(len, 1 << 9);
1210                 start = aligned_start;
1211         }
1212
1213         *discarded_bytes = 0;
1214
1215         if (!len)
1216                 return 0;
1217
1218         end = start + len;
1219         bytes_left = len;
1220
1221         /* Skip any superblocks on this device. */
1222         for (j = 0; j < BTRFS_SUPER_MIRROR_MAX; j++) {
1223                 u64 sb_start = btrfs_sb_offset(j);
1224                 u64 sb_end = sb_start + BTRFS_SUPER_INFO_SIZE;
1225                 u64 size = sb_start - start;
1226
1227                 if (!in_range(sb_start, start, bytes_left) &&
1228                     !in_range(sb_end, start, bytes_left) &&
1229                     !in_range(start, sb_start, BTRFS_SUPER_INFO_SIZE))
1230                         continue;
1231
1232                 /*
1233                  * Superblock spans beginning of range.  Adjust start and
1234                  * try again.
1235                  */
1236                 if (sb_start <= start) {
1237                         start += sb_end - start;
1238                         if (start > end) {
1239                                 bytes_left = 0;
1240                                 break;
1241                         }
1242                         bytes_left = end - start;
1243                         continue;
1244                 }
1245
1246                 if (size) {
1247                         ret = blkdev_issue_discard(bdev, start >> 9, size >> 9,
1248                                                    GFP_NOFS);
1249                         if (!ret)
1250                                 *discarded_bytes += size;
1251                         else if (ret != -EOPNOTSUPP)
1252                                 return ret;
1253                 }
1254
1255                 start = sb_end;
1256                 if (start > end) {
1257                         bytes_left = 0;
1258                         break;
1259                 }
1260                 bytes_left = end - start;
1261         }
1262
1263         if (bytes_left) {
1264                 ret = blkdev_issue_discard(bdev, start >> 9, bytes_left >> 9,
1265                                            GFP_NOFS);
1266                 if (!ret)
1267                         *discarded_bytes += bytes_left;
1268         }
1269         return ret;
1270 }
1271
1272 static int do_discard_extent(struct btrfs_discard_stripe *stripe, u64 *bytes)
1273 {
1274         struct btrfs_device *dev = stripe->dev;
1275         struct btrfs_fs_info *fs_info = dev->fs_info;
1276         struct btrfs_dev_replace *dev_replace = &fs_info->dev_replace;
1277         u64 phys = stripe->physical;
1278         u64 len = stripe->length;
1279         u64 discarded = 0;
1280         int ret = 0;
1281
1282         /* Zone reset on a zoned filesystem */
1283         if (btrfs_can_zone_reset(dev, phys, len)) {
1284                 u64 src_disc;
1285
1286                 ret = btrfs_reset_device_zone(dev, phys, len, &discarded);
1287                 if (ret)
1288                         goto out;
1289
1290                 if (!btrfs_dev_replace_is_ongoing(dev_replace) ||
1291                     dev != dev_replace->srcdev)
1292                         goto out;
1293
1294                 src_disc = discarded;
1295
1296                 /* Send to replace target as well */
1297                 ret = btrfs_reset_device_zone(dev_replace->tgtdev, phys, len,
1298                                               &discarded);
1299                 discarded += src_disc;
1300         } else if (bdev_max_discard_sectors(stripe->dev->bdev)) {
1301                 ret = btrfs_issue_discard(dev->bdev, phys, len, &discarded);
1302         } else {
1303                 ret = 0;
1304                 *bytes = 0;
1305         }
1306
1307 out:
1308         *bytes = discarded;
1309         return ret;
1310 }
1311
1312 int btrfs_discard_extent(struct btrfs_fs_info *fs_info, u64 bytenr,
1313                          u64 num_bytes, u64 *actual_bytes)
1314 {
1315         int ret = 0;
1316         u64 discarded_bytes = 0;
1317         u64 end = bytenr + num_bytes;
1318         u64 cur = bytenr;
1319
1320         /*
1321          * Avoid races with device replace and make sure the devices in the
1322          * stripes don't go away while we are discarding.
1323          */
1324         btrfs_bio_counter_inc_blocked(fs_info);
1325         while (cur < end) {
1326                 struct btrfs_discard_stripe *stripes;
1327                 unsigned int num_stripes;
1328                 int i;
1329
1330                 num_bytes = end - cur;
1331                 stripes = btrfs_map_discard(fs_info, cur, &num_bytes, &num_stripes);
1332                 if (IS_ERR(stripes)) {
1333                         ret = PTR_ERR(stripes);
1334                         if (ret == -EOPNOTSUPP)
1335                                 ret = 0;
1336                         break;
1337                 }
1338
1339                 for (i = 0; i < num_stripes; i++) {
1340                         struct btrfs_discard_stripe *stripe = stripes + i;
1341                         u64 bytes;
1342
1343                         if (!stripe->dev->bdev) {
1344                                 ASSERT(btrfs_test_opt(fs_info, DEGRADED));
1345                                 continue;
1346                         }
1347
1348                         if (!test_bit(BTRFS_DEV_STATE_WRITEABLE,
1349                                         &stripe->dev->dev_state))
1350                                 continue;
1351
1352                         ret = do_discard_extent(stripe, &bytes);
1353                         if (ret) {
1354                                 /*
1355                                  * Keep going if discard is not supported by the
1356                                  * device.
1357                                  */
1358                                 if (ret != -EOPNOTSUPP)
1359                                         break;
1360                                 ret = 0;
1361                         } else {
1362                                 discarded_bytes += bytes;
1363                         }
1364                 }
1365                 kfree(stripes);
1366                 if (ret)
1367                         break;
1368                 cur += num_bytes;
1369         }
1370         btrfs_bio_counter_dec(fs_info);
1371         if (actual_bytes)
1372                 *actual_bytes = discarded_bytes;
1373         return ret;
1374 }
1375
1376 /* Can return -ENOMEM */
1377 int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1378                          struct btrfs_ref *generic_ref)
1379 {
1380         struct btrfs_fs_info *fs_info = trans->fs_info;
1381         int ret;
1382
1383         ASSERT(generic_ref->type != BTRFS_REF_NOT_SET &&
1384                generic_ref->action);
1385         BUG_ON(generic_ref->type == BTRFS_REF_METADATA &&
1386                generic_ref->tree_ref.owning_root == BTRFS_TREE_LOG_OBJECTID);
1387
1388         if (generic_ref->type == BTRFS_REF_METADATA)
1389                 ret = btrfs_add_delayed_tree_ref(trans, generic_ref, NULL);
1390         else
1391                 ret = btrfs_add_delayed_data_ref(trans, generic_ref, 0);
1392
1393         btrfs_ref_tree_mod(fs_info, generic_ref);
1394
1395         return ret;
1396 }
1397
1398 /*
1399  * __btrfs_inc_extent_ref - insert backreference for a given extent
1400  *
1401  * The counterpart is in __btrfs_free_extent(), with examples and more details
1402  * how it works.
1403  *
1404  * @trans:          Handle of transaction
1405  *
1406  * @node:           The delayed ref node used to get the bytenr/length for
1407  *                  extent whose references are incremented.
1408  *
1409  * @parent:         If this is a shared extent (BTRFS_SHARED_DATA_REF_KEY/
1410  *                  BTRFS_SHARED_BLOCK_REF_KEY) then it holds the logical
1411  *                  bytenr of the parent block. Since new extents are always
1412  *                  created with indirect references, this will only be the case
1413  *                  when relocating a shared extent. In that case, root_objectid
1414  *                  will be BTRFS_TREE_RELOC_OBJECTID. Otherwise, parent must
1415  *                  be 0
1416  *
1417  * @root_objectid:  The id of the root where this modification has originated,
1418  *                  this can be either one of the well-known metadata trees or
1419  *                  the subvolume id which references this extent.
1420  *
1421  * @owner:          For data extents it is the inode number of the owning file.
1422  *                  For metadata extents this parameter holds the level in the
1423  *                  tree of the extent.
1424  *
1425  * @offset:         For metadata extents the offset is ignored and is currently
1426  *                  always passed as 0. For data extents it is the fileoffset
1427  *                  this extent belongs to.
1428  *
1429  * @refs_to_add     Number of references to add
1430  *
1431  * @extent_op       Pointer to a structure, holding information necessary when
1432  *                  updating a tree block's flags
1433  *
1434  */
1435 static int __btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
1436                                   struct btrfs_delayed_ref_node *node,
1437                                   u64 parent, u64 root_objectid,
1438                                   u64 owner, u64 offset, int refs_to_add,
1439                                   struct btrfs_delayed_extent_op *extent_op)
1440 {
1441         struct btrfs_path *path;
1442         struct extent_buffer *leaf;
1443         struct btrfs_extent_item *item;
1444         struct btrfs_key key;
1445         u64 bytenr = node->bytenr;
1446         u64 num_bytes = node->num_bytes;
1447         u64 refs;
1448         int ret;
1449
1450         path = btrfs_alloc_path();
1451         if (!path)
1452                 return -ENOMEM;
1453
1454         /* this will setup the path even if it fails to insert the back ref */
1455         ret = insert_inline_extent_backref(trans, path, bytenr, num_bytes,
1456                                            parent, root_objectid, owner,
1457                                            offset, refs_to_add, extent_op);
1458         if ((ret < 0 && ret != -EAGAIN) || !ret)
1459                 goto out;
1460
1461         /*
1462          * Ok we had -EAGAIN which means we didn't have space to insert and
1463          * inline extent ref, so just update the reference count and add a
1464          * normal backref.
1465          */
1466         leaf = path->nodes[0];
1467         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
1468         item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1469         refs = btrfs_extent_refs(leaf, item);
1470         btrfs_set_extent_refs(leaf, item, refs + refs_to_add);
1471         if (extent_op)
1472                 __run_delayed_extent_op(extent_op, leaf, item);
1473
1474         btrfs_mark_buffer_dirty(leaf);
1475         btrfs_release_path(path);
1476
1477         /* now insert the actual backref */
1478         if (owner < BTRFS_FIRST_FREE_OBJECTID) {
1479                 BUG_ON(refs_to_add != 1);
1480                 ret = insert_tree_block_ref(trans, path, bytenr, parent,
1481                                             root_objectid);
1482         } else {
1483                 ret = insert_extent_data_ref(trans, path, bytenr, parent,
1484                                              root_objectid, owner, offset,
1485                                              refs_to_add);
1486         }
1487         if (ret)
1488                 btrfs_abort_transaction(trans, ret);
1489 out:
1490         btrfs_free_path(path);
1491         return ret;
1492 }
1493
1494 static int run_delayed_data_ref(struct btrfs_trans_handle *trans,
1495                                 struct btrfs_delayed_ref_node *node,
1496                                 struct btrfs_delayed_extent_op *extent_op,
1497                                 int insert_reserved)
1498 {
1499         int ret = 0;
1500         struct btrfs_delayed_data_ref *ref;
1501         struct btrfs_key ins;
1502         u64 parent = 0;
1503         u64 ref_root = 0;
1504         u64 flags = 0;
1505
1506         ins.objectid = node->bytenr;
1507         ins.offset = node->num_bytes;
1508         ins.type = BTRFS_EXTENT_ITEM_KEY;
1509
1510         ref = btrfs_delayed_node_to_data_ref(node);
1511         trace_run_delayed_data_ref(trans->fs_info, node, ref, node->action);
1512
1513         if (node->type == BTRFS_SHARED_DATA_REF_KEY)
1514                 parent = ref->parent;
1515         ref_root = ref->root;
1516
1517         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1518                 if (extent_op)
1519                         flags |= extent_op->flags_to_set;
1520                 ret = alloc_reserved_file_extent(trans, parent, ref_root,
1521                                                  flags, ref->objectid,
1522                                                  ref->offset, &ins,
1523                                                  node->ref_mod);
1524         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1525                 ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
1526                                              ref->objectid, ref->offset,
1527                                              node->ref_mod, extent_op);
1528         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1529                 ret = __btrfs_free_extent(trans, node, parent,
1530                                           ref_root, ref->objectid,
1531                                           ref->offset, node->ref_mod,
1532                                           extent_op);
1533         } else {
1534                 BUG();
1535         }
1536         return ret;
1537 }
1538
1539 static void __run_delayed_extent_op(struct btrfs_delayed_extent_op *extent_op,
1540                                     struct extent_buffer *leaf,
1541                                     struct btrfs_extent_item *ei)
1542 {
1543         u64 flags = btrfs_extent_flags(leaf, ei);
1544         if (extent_op->update_flags) {
1545                 flags |= extent_op->flags_to_set;
1546                 btrfs_set_extent_flags(leaf, ei, flags);
1547         }
1548
1549         if (extent_op->update_key) {
1550                 struct btrfs_tree_block_info *bi;
1551                 BUG_ON(!(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK));
1552                 bi = (struct btrfs_tree_block_info *)(ei + 1);
1553                 btrfs_set_tree_block_key(leaf, bi, &extent_op->key);
1554         }
1555 }
1556
1557 static int run_delayed_extent_op(struct btrfs_trans_handle *trans,
1558                                  struct btrfs_delayed_ref_head *head,
1559                                  struct btrfs_delayed_extent_op *extent_op)
1560 {
1561         struct btrfs_fs_info *fs_info = trans->fs_info;
1562         struct btrfs_root *root;
1563         struct btrfs_key key;
1564         struct btrfs_path *path;
1565         struct btrfs_extent_item *ei;
1566         struct extent_buffer *leaf;
1567         u32 item_size;
1568         int ret;
1569         int err = 0;
1570         int metadata = 1;
1571
1572         if (TRANS_ABORTED(trans))
1573                 return 0;
1574
1575         if (!btrfs_fs_incompat(fs_info, SKINNY_METADATA))
1576                 metadata = 0;
1577
1578         path = btrfs_alloc_path();
1579         if (!path)
1580                 return -ENOMEM;
1581
1582         key.objectid = head->bytenr;
1583
1584         if (metadata) {
1585                 key.type = BTRFS_METADATA_ITEM_KEY;
1586                 key.offset = extent_op->level;
1587         } else {
1588                 key.type = BTRFS_EXTENT_ITEM_KEY;
1589                 key.offset = head->num_bytes;
1590         }
1591
1592         root = btrfs_extent_root(fs_info, key.objectid);
1593 again:
1594         ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1595         if (ret < 0) {
1596                 err = ret;
1597                 goto out;
1598         }
1599         if (ret > 0) {
1600                 if (metadata) {
1601                         if (path->slots[0] > 0) {
1602                                 path->slots[0]--;
1603                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
1604                                                       path->slots[0]);
1605                                 if (key.objectid == head->bytenr &&
1606                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
1607                                     key.offset == head->num_bytes)
1608                                         ret = 0;
1609                         }
1610                         if (ret > 0) {
1611                                 btrfs_release_path(path);
1612                                 metadata = 0;
1613
1614                                 key.objectid = head->bytenr;
1615                                 key.offset = head->num_bytes;
1616                                 key.type = BTRFS_EXTENT_ITEM_KEY;
1617                                 goto again;
1618                         }
1619                 } else {
1620                         err = -EIO;
1621                         goto out;
1622                 }
1623         }
1624
1625         leaf = path->nodes[0];
1626         item_size = btrfs_item_size(leaf, path->slots[0]);
1627
1628         if (unlikely(item_size < sizeof(*ei))) {
1629                 err = -EINVAL;
1630                 btrfs_print_v0_err(fs_info);
1631                 btrfs_abort_transaction(trans, err);
1632                 goto out;
1633         }
1634
1635         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
1636         __run_delayed_extent_op(extent_op, leaf, ei);
1637
1638         btrfs_mark_buffer_dirty(leaf);
1639 out:
1640         btrfs_free_path(path);
1641         return err;
1642 }
1643
1644 static int run_delayed_tree_ref(struct btrfs_trans_handle *trans,
1645                                 struct btrfs_delayed_ref_node *node,
1646                                 struct btrfs_delayed_extent_op *extent_op,
1647                                 int insert_reserved)
1648 {
1649         int ret = 0;
1650         struct btrfs_delayed_tree_ref *ref;
1651         u64 parent = 0;
1652         u64 ref_root = 0;
1653
1654         ref = btrfs_delayed_node_to_tree_ref(node);
1655         trace_run_delayed_tree_ref(trans->fs_info, node, ref, node->action);
1656
1657         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1658                 parent = ref->parent;
1659         ref_root = ref->root;
1660
1661         if (node->ref_mod != 1) {
1662                 btrfs_err(trans->fs_info,
1663         "btree block(%llu) has %d references rather than 1: action %d ref_root %llu parent %llu",
1664                           node->bytenr, node->ref_mod, node->action, ref_root,
1665                           parent);
1666                 return -EIO;
1667         }
1668         if (node->action == BTRFS_ADD_DELAYED_REF && insert_reserved) {
1669                 BUG_ON(!extent_op || !extent_op->update_flags);
1670                 ret = alloc_reserved_tree_block(trans, node, extent_op);
1671         } else if (node->action == BTRFS_ADD_DELAYED_REF) {
1672                 ret = __btrfs_inc_extent_ref(trans, node, parent, ref_root,
1673                                              ref->level, 0, 1, extent_op);
1674         } else if (node->action == BTRFS_DROP_DELAYED_REF) {
1675                 ret = __btrfs_free_extent(trans, node, parent, ref_root,
1676                                           ref->level, 0, 1, extent_op);
1677         } else {
1678                 BUG();
1679         }
1680         return ret;
1681 }
1682
1683 /* helper function to actually process a single delayed ref entry */
1684 static int run_one_delayed_ref(struct btrfs_trans_handle *trans,
1685                                struct btrfs_delayed_ref_node *node,
1686                                struct btrfs_delayed_extent_op *extent_op,
1687                                int insert_reserved)
1688 {
1689         int ret = 0;
1690
1691         if (TRANS_ABORTED(trans)) {
1692                 if (insert_reserved)
1693                         btrfs_pin_extent(trans, node->bytenr, node->num_bytes, 1);
1694                 return 0;
1695         }
1696
1697         if (node->type == BTRFS_TREE_BLOCK_REF_KEY ||
1698             node->type == BTRFS_SHARED_BLOCK_REF_KEY)
1699                 ret = run_delayed_tree_ref(trans, node, extent_op,
1700                                            insert_reserved);
1701         else if (node->type == BTRFS_EXTENT_DATA_REF_KEY ||
1702                  node->type == BTRFS_SHARED_DATA_REF_KEY)
1703                 ret = run_delayed_data_ref(trans, node, extent_op,
1704                                            insert_reserved);
1705         else
1706                 BUG();
1707         if (ret && insert_reserved)
1708                 btrfs_pin_extent(trans, node->bytenr, node->num_bytes, 1);
1709         return ret;
1710 }
1711
1712 static inline struct btrfs_delayed_ref_node *
1713 select_delayed_ref(struct btrfs_delayed_ref_head *head)
1714 {
1715         struct btrfs_delayed_ref_node *ref;
1716
1717         if (RB_EMPTY_ROOT(&head->ref_tree.rb_root))
1718                 return NULL;
1719
1720         /*
1721          * Select a delayed ref of type BTRFS_ADD_DELAYED_REF first.
1722          * This is to prevent a ref count from going down to zero, which deletes
1723          * the extent item from the extent tree, when there still are references
1724          * to add, which would fail because they would not find the extent item.
1725          */
1726         if (!list_empty(&head->ref_add_list))
1727                 return list_first_entry(&head->ref_add_list,
1728                                 struct btrfs_delayed_ref_node, add_list);
1729
1730         ref = rb_entry(rb_first_cached(&head->ref_tree),
1731                        struct btrfs_delayed_ref_node, ref_node);
1732         ASSERT(list_empty(&ref->add_list));
1733         return ref;
1734 }
1735
1736 static void unselect_delayed_ref_head(struct btrfs_delayed_ref_root *delayed_refs,
1737                                       struct btrfs_delayed_ref_head *head)
1738 {
1739         spin_lock(&delayed_refs->lock);
1740         head->processing = 0;
1741         delayed_refs->num_heads_ready++;
1742         spin_unlock(&delayed_refs->lock);
1743         btrfs_delayed_ref_unlock(head);
1744 }
1745
1746 static struct btrfs_delayed_extent_op *cleanup_extent_op(
1747                                 struct btrfs_delayed_ref_head *head)
1748 {
1749         struct btrfs_delayed_extent_op *extent_op = head->extent_op;
1750
1751         if (!extent_op)
1752                 return NULL;
1753
1754         if (head->must_insert_reserved) {
1755                 head->extent_op = NULL;
1756                 btrfs_free_delayed_extent_op(extent_op);
1757                 return NULL;
1758         }
1759         return extent_op;
1760 }
1761
1762 static int run_and_cleanup_extent_op(struct btrfs_trans_handle *trans,
1763                                      struct btrfs_delayed_ref_head *head)
1764 {
1765         struct btrfs_delayed_extent_op *extent_op;
1766         int ret;
1767
1768         extent_op = cleanup_extent_op(head);
1769         if (!extent_op)
1770                 return 0;
1771         head->extent_op = NULL;
1772         spin_unlock(&head->lock);
1773         ret = run_delayed_extent_op(trans, head, extent_op);
1774         btrfs_free_delayed_extent_op(extent_op);
1775         return ret ? ret : 1;
1776 }
1777
1778 void btrfs_cleanup_ref_head_accounting(struct btrfs_fs_info *fs_info,
1779                                   struct btrfs_delayed_ref_root *delayed_refs,
1780                                   struct btrfs_delayed_ref_head *head)
1781 {
1782         int nr_items = 1;       /* Dropping this ref head update. */
1783
1784         /*
1785          * We had csum deletions accounted for in our delayed refs rsv, we need
1786          * to drop the csum leaves for this update from our delayed_refs_rsv.
1787          */
1788         if (head->total_ref_mod < 0 && head->is_data) {
1789                 spin_lock(&delayed_refs->lock);
1790                 delayed_refs->pending_csums -= head->num_bytes;
1791                 spin_unlock(&delayed_refs->lock);
1792                 nr_items += btrfs_csum_bytes_to_leaves(fs_info, head->num_bytes);
1793         }
1794
1795         btrfs_delayed_refs_rsv_release(fs_info, nr_items);
1796 }
1797
1798 static int cleanup_ref_head(struct btrfs_trans_handle *trans,
1799                             struct btrfs_delayed_ref_head *head)
1800 {
1801
1802         struct btrfs_fs_info *fs_info = trans->fs_info;
1803         struct btrfs_delayed_ref_root *delayed_refs;
1804         int ret;
1805
1806         delayed_refs = &trans->transaction->delayed_refs;
1807
1808         ret = run_and_cleanup_extent_op(trans, head);
1809         if (ret < 0) {
1810                 unselect_delayed_ref_head(delayed_refs, head);
1811                 btrfs_debug(fs_info, "run_delayed_extent_op returned %d", ret);
1812                 return ret;
1813         } else if (ret) {
1814                 return ret;
1815         }
1816
1817         /*
1818          * Need to drop our head ref lock and re-acquire the delayed ref lock
1819          * and then re-check to make sure nobody got added.
1820          */
1821         spin_unlock(&head->lock);
1822         spin_lock(&delayed_refs->lock);
1823         spin_lock(&head->lock);
1824         if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root) || head->extent_op) {
1825                 spin_unlock(&head->lock);
1826                 spin_unlock(&delayed_refs->lock);
1827                 return 1;
1828         }
1829         btrfs_delete_ref_head(delayed_refs, head);
1830         spin_unlock(&head->lock);
1831         spin_unlock(&delayed_refs->lock);
1832
1833         if (head->must_insert_reserved) {
1834                 btrfs_pin_extent(trans, head->bytenr, head->num_bytes, 1);
1835                 if (head->is_data) {
1836                         struct btrfs_root *csum_root;
1837
1838                         csum_root = btrfs_csum_root(fs_info, head->bytenr);
1839                         ret = btrfs_del_csums(trans, csum_root, head->bytenr,
1840                                               head->num_bytes);
1841                 }
1842         }
1843
1844         btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
1845
1846         trace_run_delayed_ref_head(fs_info, head, 0);
1847         btrfs_delayed_ref_unlock(head);
1848         btrfs_put_delayed_ref_head(head);
1849         return ret;
1850 }
1851
1852 static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
1853                                         struct btrfs_trans_handle *trans)
1854 {
1855         struct btrfs_delayed_ref_root *delayed_refs =
1856                 &trans->transaction->delayed_refs;
1857         struct btrfs_delayed_ref_head *head = NULL;
1858         int ret;
1859
1860         spin_lock(&delayed_refs->lock);
1861         head = btrfs_select_ref_head(delayed_refs);
1862         if (!head) {
1863                 spin_unlock(&delayed_refs->lock);
1864                 return head;
1865         }
1866
1867         /*
1868          * Grab the lock that says we are going to process all the refs for
1869          * this head
1870          */
1871         ret = btrfs_delayed_ref_lock(delayed_refs, head);
1872         spin_unlock(&delayed_refs->lock);
1873
1874         /*
1875          * We may have dropped the spin lock to get the head mutex lock, and
1876          * that might have given someone else time to free the head.  If that's
1877          * true, it has been removed from our list and we can move on.
1878          */
1879         if (ret == -EAGAIN)
1880                 head = ERR_PTR(-EAGAIN);
1881
1882         return head;
1883 }
1884
1885 static int btrfs_run_delayed_refs_for_head(struct btrfs_trans_handle *trans,
1886                                     struct btrfs_delayed_ref_head *locked_ref,
1887                                     unsigned long *run_refs)
1888 {
1889         struct btrfs_fs_info *fs_info = trans->fs_info;
1890         struct btrfs_delayed_ref_root *delayed_refs;
1891         struct btrfs_delayed_extent_op *extent_op;
1892         struct btrfs_delayed_ref_node *ref;
1893         int must_insert_reserved = 0;
1894         int ret;
1895
1896         delayed_refs = &trans->transaction->delayed_refs;
1897
1898         lockdep_assert_held(&locked_ref->mutex);
1899         lockdep_assert_held(&locked_ref->lock);
1900
1901         while ((ref = select_delayed_ref(locked_ref))) {
1902                 if (ref->seq &&
1903                     btrfs_check_delayed_seq(fs_info, ref->seq)) {
1904                         spin_unlock(&locked_ref->lock);
1905                         unselect_delayed_ref_head(delayed_refs, locked_ref);
1906                         return -EAGAIN;
1907                 }
1908
1909                 (*run_refs)++;
1910                 ref->in_tree = 0;
1911                 rb_erase_cached(&ref->ref_node, &locked_ref->ref_tree);
1912                 RB_CLEAR_NODE(&ref->ref_node);
1913                 if (!list_empty(&ref->add_list))
1914                         list_del(&ref->add_list);
1915                 /*
1916                  * When we play the delayed ref, also correct the ref_mod on
1917                  * head
1918                  */
1919                 switch (ref->action) {
1920                 case BTRFS_ADD_DELAYED_REF:
1921                 case BTRFS_ADD_DELAYED_EXTENT:
1922                         locked_ref->ref_mod -= ref->ref_mod;
1923                         break;
1924                 case BTRFS_DROP_DELAYED_REF:
1925                         locked_ref->ref_mod += ref->ref_mod;
1926                         break;
1927                 default:
1928                         WARN_ON(1);
1929                 }
1930                 atomic_dec(&delayed_refs->num_entries);
1931
1932                 /*
1933                  * Record the must_insert_reserved flag before we drop the
1934                  * spin lock.
1935                  */
1936                 must_insert_reserved = locked_ref->must_insert_reserved;
1937                 locked_ref->must_insert_reserved = 0;
1938
1939                 extent_op = locked_ref->extent_op;
1940                 locked_ref->extent_op = NULL;
1941                 spin_unlock(&locked_ref->lock);
1942
1943                 ret = run_one_delayed_ref(trans, ref, extent_op,
1944                                           must_insert_reserved);
1945
1946                 btrfs_free_delayed_extent_op(extent_op);
1947                 if (ret) {
1948                         unselect_delayed_ref_head(delayed_refs, locked_ref);
1949                         btrfs_put_delayed_ref(ref);
1950                         btrfs_debug(fs_info, "run_one_delayed_ref returned %d",
1951                                     ret);
1952                         return ret;
1953                 }
1954
1955                 btrfs_put_delayed_ref(ref);
1956                 cond_resched();
1957
1958                 spin_lock(&locked_ref->lock);
1959                 btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
1960         }
1961
1962         return 0;
1963 }
1964
1965 /*
1966  * Returns 0 on success or if called with an already aborted transaction.
1967  * Returns -ENOMEM or -EIO on failure and will abort the transaction.
1968  */
1969 static noinline int __btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
1970                                              unsigned long nr)
1971 {
1972         struct btrfs_fs_info *fs_info = trans->fs_info;
1973         struct btrfs_delayed_ref_root *delayed_refs;
1974         struct btrfs_delayed_ref_head *locked_ref = NULL;
1975         ktime_t start = ktime_get();
1976         int ret;
1977         unsigned long count = 0;
1978         unsigned long actual_count = 0;
1979
1980         delayed_refs = &trans->transaction->delayed_refs;
1981         do {
1982                 if (!locked_ref) {
1983                         locked_ref = btrfs_obtain_ref_head(trans);
1984                         if (IS_ERR_OR_NULL(locked_ref)) {
1985                                 if (PTR_ERR(locked_ref) == -EAGAIN) {
1986                                         continue;
1987                                 } else {
1988                                         break;
1989                                 }
1990                         }
1991                         count++;
1992                 }
1993                 /*
1994                  * We need to try and merge add/drops of the same ref since we
1995                  * can run into issues with relocate dropping the implicit ref
1996                  * and then it being added back again before the drop can
1997                  * finish.  If we merged anything we need to re-loop so we can
1998                  * get a good ref.
1999                  * Or we can get node references of the same type that weren't
2000                  * merged when created due to bumps in the tree mod seq, and
2001                  * we need to merge them to prevent adding an inline extent
2002                  * backref before dropping it (triggering a BUG_ON at
2003                  * insert_inline_extent_backref()).
2004                  */
2005                 spin_lock(&locked_ref->lock);
2006                 btrfs_merge_delayed_refs(trans, delayed_refs, locked_ref);
2007
2008                 ret = btrfs_run_delayed_refs_for_head(trans, locked_ref,
2009                                                       &actual_count);
2010                 if (ret < 0 && ret != -EAGAIN) {
2011                         /*
2012                          * Error, btrfs_run_delayed_refs_for_head already
2013                          * unlocked everything so just bail out
2014                          */
2015                         return ret;
2016                 } else if (!ret) {
2017                         /*
2018                          * Success, perform the usual cleanup of a processed
2019                          * head
2020                          */
2021                         ret = cleanup_ref_head(trans, locked_ref);
2022                         if (ret > 0 ) {
2023                                 /* We dropped our lock, we need to loop. */
2024                                 ret = 0;
2025                                 continue;
2026                         } else if (ret) {
2027                                 return ret;
2028                         }
2029                 }
2030
2031                 /*
2032                  * Either success case or btrfs_run_delayed_refs_for_head
2033                  * returned -EAGAIN, meaning we need to select another head
2034                  */
2035
2036                 locked_ref = NULL;
2037                 cond_resched();
2038         } while ((nr != -1 && count < nr) || locked_ref);
2039
2040         /*
2041          * We don't want to include ref heads since we can have empty ref heads
2042          * and those will drastically skew our runtime down since we just do
2043          * accounting, no actual extent tree updates.
2044          */
2045         if (actual_count > 0) {
2046                 u64 runtime = ktime_to_ns(ktime_sub(ktime_get(), start));
2047                 u64 avg;
2048
2049                 /*
2050                  * We weigh the current average higher than our current runtime
2051                  * to avoid large swings in the average.
2052                  */
2053                 spin_lock(&delayed_refs->lock);
2054                 avg = fs_info->avg_delayed_ref_runtime * 3 + runtime;
2055                 fs_info->avg_delayed_ref_runtime = avg >> 2;    /* div by 4 */
2056                 spin_unlock(&delayed_refs->lock);
2057         }
2058         return 0;
2059 }
2060
2061 #ifdef SCRAMBLE_DELAYED_REFS
2062 /*
2063  * Normally delayed refs get processed in ascending bytenr order. This
2064  * correlates in most cases to the order added. To expose dependencies on this
2065  * order, we start to process the tree in the middle instead of the beginning
2066  */
2067 static u64 find_middle(struct rb_root *root)
2068 {
2069         struct rb_node *n = root->rb_node;
2070         struct btrfs_delayed_ref_node *entry;
2071         int alt = 1;
2072         u64 middle;
2073         u64 first = 0, last = 0;
2074
2075         n = rb_first(root);
2076         if (n) {
2077                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2078                 first = entry->bytenr;
2079         }
2080         n = rb_last(root);
2081         if (n) {
2082                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2083                 last = entry->bytenr;
2084         }
2085         n = root->rb_node;
2086
2087         while (n) {
2088                 entry = rb_entry(n, struct btrfs_delayed_ref_node, rb_node);
2089                 WARN_ON(!entry->in_tree);
2090
2091                 middle = entry->bytenr;
2092
2093                 if (alt)
2094                         n = n->rb_left;
2095                 else
2096                         n = n->rb_right;
2097
2098                 alt = 1 - alt;
2099         }
2100         return middle;
2101 }
2102 #endif
2103
2104 /*
2105  * this starts processing the delayed reference count updates and
2106  * extent insertions we have queued up so far.  count can be
2107  * 0, which means to process everything in the tree at the start
2108  * of the run (but not newly added entries), or it can be some target
2109  * number you'd like to process.
2110  *
2111  * Returns 0 on success or if called with an aborted transaction
2112  * Returns <0 on error and aborts the transaction
2113  */
2114 int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
2115                            unsigned long count)
2116 {
2117         struct btrfs_fs_info *fs_info = trans->fs_info;
2118         struct rb_node *node;
2119         struct btrfs_delayed_ref_root *delayed_refs;
2120         struct btrfs_delayed_ref_head *head;
2121         int ret;
2122         int run_all = count == (unsigned long)-1;
2123
2124         /* We'll clean this up in btrfs_cleanup_transaction */
2125         if (TRANS_ABORTED(trans))
2126                 return 0;
2127
2128         if (test_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags))
2129                 return 0;
2130
2131         delayed_refs = &trans->transaction->delayed_refs;
2132         if (count == 0)
2133                 count = delayed_refs->num_heads_ready;
2134
2135 again:
2136 #ifdef SCRAMBLE_DELAYED_REFS
2137         delayed_refs->run_delayed_start = find_middle(&delayed_refs->root);
2138 #endif
2139         ret = __btrfs_run_delayed_refs(trans, count);
2140         if (ret < 0) {
2141                 btrfs_abort_transaction(trans, ret);
2142                 return ret;
2143         }
2144
2145         if (run_all) {
2146                 btrfs_create_pending_block_groups(trans);
2147
2148                 spin_lock(&delayed_refs->lock);
2149                 node = rb_first_cached(&delayed_refs->href_root);
2150                 if (!node) {
2151                         spin_unlock(&delayed_refs->lock);
2152                         goto out;
2153                 }
2154                 head = rb_entry(node, struct btrfs_delayed_ref_head,
2155                                 href_node);
2156                 refcount_inc(&head->refs);
2157                 spin_unlock(&delayed_refs->lock);
2158
2159                 /* Mutex was contended, block until it's released and retry. */
2160                 mutex_lock(&head->mutex);
2161                 mutex_unlock(&head->mutex);
2162
2163                 btrfs_put_delayed_ref_head(head);
2164                 cond_resched();
2165                 goto again;
2166         }
2167 out:
2168         return 0;
2169 }
2170
2171 int btrfs_set_disk_extent_flags(struct btrfs_trans_handle *trans,
2172                                 struct extent_buffer *eb, u64 flags,
2173                                 int level)
2174 {
2175         struct btrfs_delayed_extent_op *extent_op;
2176         int ret;
2177
2178         extent_op = btrfs_alloc_delayed_extent_op();
2179         if (!extent_op)
2180                 return -ENOMEM;
2181
2182         extent_op->flags_to_set = flags;
2183         extent_op->update_flags = true;
2184         extent_op->update_key = false;
2185         extent_op->level = level;
2186
2187         ret = btrfs_add_delayed_extent_op(trans, eb->start, eb->len, extent_op);
2188         if (ret)
2189                 btrfs_free_delayed_extent_op(extent_op);
2190         return ret;
2191 }
2192
2193 static noinline int check_delayed_ref(struct btrfs_root *root,
2194                                       struct btrfs_path *path,
2195                                       u64 objectid, u64 offset, u64 bytenr)
2196 {
2197         struct btrfs_delayed_ref_head *head;
2198         struct btrfs_delayed_ref_node *ref;
2199         struct btrfs_delayed_data_ref *data_ref;
2200         struct btrfs_delayed_ref_root *delayed_refs;
2201         struct btrfs_transaction *cur_trans;
2202         struct rb_node *node;
2203         int ret = 0;
2204
2205         spin_lock(&root->fs_info->trans_lock);
2206         cur_trans = root->fs_info->running_transaction;
2207         if (cur_trans)
2208                 refcount_inc(&cur_trans->use_count);
2209         spin_unlock(&root->fs_info->trans_lock);
2210         if (!cur_trans)
2211                 return 0;
2212
2213         delayed_refs = &cur_trans->delayed_refs;
2214         spin_lock(&delayed_refs->lock);
2215         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
2216         if (!head) {
2217                 spin_unlock(&delayed_refs->lock);
2218                 btrfs_put_transaction(cur_trans);
2219                 return 0;
2220         }
2221
2222         if (!mutex_trylock(&head->mutex)) {
2223                 refcount_inc(&head->refs);
2224                 spin_unlock(&delayed_refs->lock);
2225
2226                 btrfs_release_path(path);
2227
2228                 /*
2229                  * Mutex was contended, block until it's released and let
2230                  * caller try again
2231                  */
2232                 mutex_lock(&head->mutex);
2233                 mutex_unlock(&head->mutex);
2234                 btrfs_put_delayed_ref_head(head);
2235                 btrfs_put_transaction(cur_trans);
2236                 return -EAGAIN;
2237         }
2238         spin_unlock(&delayed_refs->lock);
2239
2240         spin_lock(&head->lock);
2241         /*
2242          * XXX: We should replace this with a proper search function in the
2243          * future.
2244          */
2245         for (node = rb_first_cached(&head->ref_tree); node;
2246              node = rb_next(node)) {
2247                 ref = rb_entry(node, struct btrfs_delayed_ref_node, ref_node);
2248                 /* If it's a shared ref we know a cross reference exists */
2249                 if (ref->type != BTRFS_EXTENT_DATA_REF_KEY) {
2250                         ret = 1;
2251                         break;
2252                 }
2253
2254                 data_ref = btrfs_delayed_node_to_data_ref(ref);
2255
2256                 /*
2257                  * If our ref doesn't match the one we're currently looking at
2258                  * then we have a cross reference.
2259                  */
2260                 if (data_ref->root != root->root_key.objectid ||
2261                     data_ref->objectid != objectid ||
2262                     data_ref->offset != offset) {
2263                         ret = 1;
2264                         break;
2265                 }
2266         }
2267         spin_unlock(&head->lock);
2268         mutex_unlock(&head->mutex);
2269         btrfs_put_transaction(cur_trans);
2270         return ret;
2271 }
2272
2273 static noinline int check_committed_ref(struct btrfs_root *root,
2274                                         struct btrfs_path *path,
2275                                         u64 objectid, u64 offset, u64 bytenr,
2276                                         bool strict)
2277 {
2278         struct btrfs_fs_info *fs_info = root->fs_info;
2279         struct btrfs_root *extent_root = btrfs_extent_root(fs_info, bytenr);
2280         struct extent_buffer *leaf;
2281         struct btrfs_extent_data_ref *ref;
2282         struct btrfs_extent_inline_ref *iref;
2283         struct btrfs_extent_item *ei;
2284         struct btrfs_key key;
2285         u32 item_size;
2286         int type;
2287         int ret;
2288
2289         key.objectid = bytenr;
2290         key.offset = (u64)-1;
2291         key.type = BTRFS_EXTENT_ITEM_KEY;
2292
2293         ret = btrfs_search_slot(NULL, extent_root, &key, path, 0, 0);
2294         if (ret < 0)
2295                 goto out;
2296         BUG_ON(ret == 0); /* Corruption */
2297
2298         ret = -ENOENT;
2299         if (path->slots[0] == 0)
2300                 goto out;
2301
2302         path->slots[0]--;
2303         leaf = path->nodes[0];
2304         btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
2305
2306         if (key.objectid != bytenr || key.type != BTRFS_EXTENT_ITEM_KEY)
2307                 goto out;
2308
2309         ret = 1;
2310         item_size = btrfs_item_size(leaf, path->slots[0]);
2311         ei = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_extent_item);
2312
2313         /* If extent item has more than 1 inline ref then it's shared */
2314         if (item_size != sizeof(*ei) +
2315             btrfs_extent_inline_ref_size(BTRFS_EXTENT_DATA_REF_KEY))
2316                 goto out;
2317
2318         /*
2319          * If extent created before last snapshot => it's shared unless the
2320          * snapshot has been deleted. Use the heuristic if strict is false.
2321          */
2322         if (!strict &&
2323             (btrfs_extent_generation(leaf, ei) <=
2324              btrfs_root_last_snapshot(&root->root_item)))
2325                 goto out;
2326
2327         iref = (struct btrfs_extent_inline_ref *)(ei + 1);
2328
2329         /* If this extent has SHARED_DATA_REF then it's shared */
2330         type = btrfs_get_extent_inline_ref_type(leaf, iref, BTRFS_REF_TYPE_DATA);
2331         if (type != BTRFS_EXTENT_DATA_REF_KEY)
2332                 goto out;
2333
2334         ref = (struct btrfs_extent_data_ref *)(&iref->offset);
2335         if (btrfs_extent_refs(leaf, ei) !=
2336             btrfs_extent_data_ref_count(leaf, ref) ||
2337             btrfs_extent_data_ref_root(leaf, ref) !=
2338             root->root_key.objectid ||
2339             btrfs_extent_data_ref_objectid(leaf, ref) != objectid ||
2340             btrfs_extent_data_ref_offset(leaf, ref) != offset)
2341                 goto out;
2342
2343         ret = 0;
2344 out:
2345         return ret;
2346 }
2347
2348 int btrfs_cross_ref_exist(struct btrfs_root *root, u64 objectid, u64 offset,
2349                           u64 bytenr, bool strict, struct btrfs_path *path)
2350 {
2351         int ret;
2352
2353         do {
2354                 ret = check_committed_ref(root, path, objectid,
2355                                           offset, bytenr, strict);
2356                 if (ret && ret != -ENOENT)
2357                         goto out;
2358
2359                 ret = check_delayed_ref(root, path, objectid, offset, bytenr);
2360         } while (ret == -EAGAIN);
2361
2362 out:
2363         btrfs_release_path(path);
2364         if (btrfs_is_data_reloc_root(root))
2365                 WARN_ON(ret > 0);
2366         return ret;
2367 }
2368
2369 static int __btrfs_mod_ref(struct btrfs_trans_handle *trans,
2370                            struct btrfs_root *root,
2371                            struct extent_buffer *buf,
2372                            int full_backref, int inc)
2373 {
2374         struct btrfs_fs_info *fs_info = root->fs_info;
2375         u64 bytenr;
2376         u64 num_bytes;
2377         u64 parent;
2378         u64 ref_root;
2379         u32 nritems;
2380         struct btrfs_key key;
2381         struct btrfs_file_extent_item *fi;
2382         struct btrfs_ref generic_ref = { 0 };
2383         bool for_reloc = btrfs_header_flag(buf, BTRFS_HEADER_FLAG_RELOC);
2384         int i;
2385         int action;
2386         int level;
2387         int ret = 0;
2388
2389         if (btrfs_is_testing(fs_info))
2390                 return 0;
2391
2392         ref_root = btrfs_header_owner(buf);
2393         nritems = btrfs_header_nritems(buf);
2394         level = btrfs_header_level(buf);
2395
2396         if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state) && level == 0)
2397                 return 0;
2398
2399         if (full_backref)
2400                 parent = buf->start;
2401         else
2402                 parent = 0;
2403         if (inc)
2404                 action = BTRFS_ADD_DELAYED_REF;
2405         else
2406                 action = BTRFS_DROP_DELAYED_REF;
2407
2408         for (i = 0; i < nritems; i++) {
2409                 if (level == 0) {
2410                         btrfs_item_key_to_cpu(buf, &key, i);
2411                         if (key.type != BTRFS_EXTENT_DATA_KEY)
2412                                 continue;
2413                         fi = btrfs_item_ptr(buf, i,
2414                                             struct btrfs_file_extent_item);
2415                         if (btrfs_file_extent_type(buf, fi) ==
2416                             BTRFS_FILE_EXTENT_INLINE)
2417                                 continue;
2418                         bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
2419                         if (bytenr == 0)
2420                                 continue;
2421
2422                         num_bytes = btrfs_file_extent_disk_num_bytes(buf, fi);
2423                         key.offset -= btrfs_file_extent_offset(buf, fi);
2424                         btrfs_init_generic_ref(&generic_ref, action, bytenr,
2425                                                num_bytes, parent);
2426                         btrfs_init_data_ref(&generic_ref, ref_root, key.objectid,
2427                                             key.offset, root->root_key.objectid,
2428                                             for_reloc);
2429                         if (inc)
2430                                 ret = btrfs_inc_extent_ref(trans, &generic_ref);
2431                         else
2432                                 ret = btrfs_free_extent(trans, &generic_ref);
2433                         if (ret)
2434                                 goto fail;
2435                 } else {
2436                         bytenr = btrfs_node_blockptr(buf, i);
2437                         num_bytes = fs_info->nodesize;
2438                         btrfs_init_generic_ref(&generic_ref, action, bytenr,
2439                                                num_bytes, parent);
2440                         btrfs_init_tree_ref(&generic_ref, level - 1, ref_root,
2441                                             root->root_key.objectid, for_reloc);
2442                         if (inc)
2443                                 ret = btrfs_inc_extent_ref(trans, &generic_ref);
2444                         else
2445                                 ret = btrfs_free_extent(trans, &generic_ref);
2446                         if (ret)
2447                                 goto fail;
2448                 }
2449         }
2450         return 0;
2451 fail:
2452         return ret;
2453 }
2454
2455 int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2456                   struct extent_buffer *buf, int full_backref)
2457 {
2458         return __btrfs_mod_ref(trans, root, buf, full_backref, 1);
2459 }
2460
2461 int btrfs_dec_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
2462                   struct extent_buffer *buf, int full_backref)
2463 {
2464         return __btrfs_mod_ref(trans, root, buf, full_backref, 0);
2465 }
2466
2467 static u64 get_alloc_profile_by_root(struct btrfs_root *root, int data)
2468 {
2469         struct btrfs_fs_info *fs_info = root->fs_info;
2470         u64 flags;
2471         u64 ret;
2472
2473         if (data)
2474                 flags = BTRFS_BLOCK_GROUP_DATA;
2475         else if (root == fs_info->chunk_root)
2476                 flags = BTRFS_BLOCK_GROUP_SYSTEM;
2477         else
2478                 flags = BTRFS_BLOCK_GROUP_METADATA;
2479
2480         ret = btrfs_get_alloc_profile(fs_info, flags);
2481         return ret;
2482 }
2483
2484 static u64 first_logical_byte(struct btrfs_fs_info *fs_info)
2485 {
2486         struct rb_node *leftmost;
2487         u64 bytenr = 0;
2488
2489         read_lock(&fs_info->block_group_cache_lock);
2490         /* Get the block group with the lowest logical start address. */
2491         leftmost = rb_first_cached(&fs_info->block_group_cache_tree);
2492         if (leftmost) {
2493                 struct btrfs_block_group *bg;
2494
2495                 bg = rb_entry(leftmost, struct btrfs_block_group, cache_node);
2496                 bytenr = bg->start;
2497         }
2498         read_unlock(&fs_info->block_group_cache_lock);
2499
2500         return bytenr;
2501 }
2502
2503 static int pin_down_extent(struct btrfs_trans_handle *trans,
2504                            struct btrfs_block_group *cache,
2505                            u64 bytenr, u64 num_bytes, int reserved)
2506 {
2507         struct btrfs_fs_info *fs_info = cache->fs_info;
2508
2509         spin_lock(&cache->space_info->lock);
2510         spin_lock(&cache->lock);
2511         cache->pinned += num_bytes;
2512         btrfs_space_info_update_bytes_pinned(fs_info, cache->space_info,
2513                                              num_bytes);
2514         if (reserved) {
2515                 cache->reserved -= num_bytes;
2516                 cache->space_info->bytes_reserved -= num_bytes;
2517         }
2518         spin_unlock(&cache->lock);
2519         spin_unlock(&cache->space_info->lock);
2520
2521         set_extent_dirty(&trans->transaction->pinned_extents, bytenr,
2522                          bytenr + num_bytes - 1, GFP_NOFS | __GFP_NOFAIL);
2523         return 0;
2524 }
2525
2526 int btrfs_pin_extent(struct btrfs_trans_handle *trans,
2527                      u64 bytenr, u64 num_bytes, int reserved)
2528 {
2529         struct btrfs_block_group *cache;
2530
2531         cache = btrfs_lookup_block_group(trans->fs_info, bytenr);
2532         BUG_ON(!cache); /* Logic error */
2533
2534         pin_down_extent(trans, cache, bytenr, num_bytes, reserved);
2535
2536         btrfs_put_block_group(cache);
2537         return 0;
2538 }
2539
2540 /*
2541  * this function must be called within transaction
2542  */
2543 int btrfs_pin_extent_for_log_replay(struct btrfs_trans_handle *trans,
2544                                     u64 bytenr, u64 num_bytes)
2545 {
2546         struct btrfs_block_group *cache;
2547         int ret;
2548
2549         cache = btrfs_lookup_block_group(trans->fs_info, bytenr);
2550         if (!cache)
2551                 return -EINVAL;
2552
2553         /*
2554          * Fully cache the free space first so that our pin removes the free space
2555          * from the cache.
2556          */
2557         ret = btrfs_cache_block_group(cache, true);
2558         if (ret)
2559                 goto out;
2560
2561         pin_down_extent(trans, cache, bytenr, num_bytes, 0);
2562
2563         /* remove us from the free space cache (if we're there at all) */
2564         ret = btrfs_remove_free_space(cache, bytenr, num_bytes);
2565 out:
2566         btrfs_put_block_group(cache);
2567         return ret;
2568 }
2569
2570 static int __exclude_logged_extent(struct btrfs_fs_info *fs_info,
2571                                    u64 start, u64 num_bytes)
2572 {
2573         int ret;
2574         struct btrfs_block_group *block_group;
2575
2576         block_group = btrfs_lookup_block_group(fs_info, start);
2577         if (!block_group)
2578                 return -EINVAL;
2579
2580         ret = btrfs_cache_block_group(block_group, true);
2581         if (ret)
2582                 goto out;
2583
2584         ret = btrfs_remove_free_space(block_group, start, num_bytes);
2585 out:
2586         btrfs_put_block_group(block_group);
2587         return ret;
2588 }
2589
2590 int btrfs_exclude_logged_extents(struct extent_buffer *eb)
2591 {
2592         struct btrfs_fs_info *fs_info = eb->fs_info;
2593         struct btrfs_file_extent_item *item;
2594         struct btrfs_key key;
2595         int found_type;
2596         int i;
2597         int ret = 0;
2598
2599         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS))
2600                 return 0;
2601
2602         for (i = 0; i < btrfs_header_nritems(eb); i++) {
2603                 btrfs_item_key_to_cpu(eb, &key, i);
2604                 if (key.type != BTRFS_EXTENT_DATA_KEY)
2605                         continue;
2606                 item = btrfs_item_ptr(eb, i, struct btrfs_file_extent_item);
2607                 found_type = btrfs_file_extent_type(eb, item);
2608                 if (found_type == BTRFS_FILE_EXTENT_INLINE)
2609                         continue;
2610                 if (btrfs_file_extent_disk_bytenr(eb, item) == 0)
2611                         continue;
2612                 key.objectid = btrfs_file_extent_disk_bytenr(eb, item);
2613                 key.offset = btrfs_file_extent_disk_num_bytes(eb, item);
2614                 ret = __exclude_logged_extent(fs_info, key.objectid, key.offset);
2615                 if (ret)
2616                         break;
2617         }
2618
2619         return ret;
2620 }
2621
2622 static void
2623 btrfs_inc_block_group_reservations(struct btrfs_block_group *bg)
2624 {
2625         atomic_inc(&bg->reservations);
2626 }
2627
2628 /*
2629  * Returns the free cluster for the given space info and sets empty_cluster to
2630  * what it should be based on the mount options.
2631  */
2632 static struct btrfs_free_cluster *
2633 fetch_cluster_info(struct btrfs_fs_info *fs_info,
2634                    struct btrfs_space_info *space_info, u64 *empty_cluster)
2635 {
2636         struct btrfs_free_cluster *ret = NULL;
2637
2638         *empty_cluster = 0;
2639         if (btrfs_mixed_space_info(space_info))
2640                 return ret;
2641
2642         if (space_info->flags & BTRFS_BLOCK_GROUP_METADATA) {
2643                 ret = &fs_info->meta_alloc_cluster;
2644                 if (btrfs_test_opt(fs_info, SSD))
2645                         *empty_cluster = SZ_2M;
2646                 else
2647                         *empty_cluster = SZ_64K;
2648         } else if ((space_info->flags & BTRFS_BLOCK_GROUP_DATA) &&
2649                    btrfs_test_opt(fs_info, SSD_SPREAD)) {
2650                 *empty_cluster = SZ_2M;
2651                 ret = &fs_info->data_alloc_cluster;
2652         }
2653
2654         return ret;
2655 }
2656
2657 static int unpin_extent_range(struct btrfs_fs_info *fs_info,
2658                               u64 start, u64 end,
2659                               const bool return_free_space)
2660 {
2661         struct btrfs_block_group *cache = NULL;
2662         struct btrfs_space_info *space_info;
2663         struct btrfs_block_rsv *global_rsv = &fs_info->global_block_rsv;
2664         struct btrfs_free_cluster *cluster = NULL;
2665         u64 len;
2666         u64 total_unpinned = 0;
2667         u64 empty_cluster = 0;
2668         bool readonly;
2669
2670         while (start <= end) {
2671                 readonly = false;
2672                 if (!cache ||
2673                     start >= cache->start + cache->length) {
2674                         if (cache)
2675                                 btrfs_put_block_group(cache);
2676                         total_unpinned = 0;
2677                         cache = btrfs_lookup_block_group(fs_info, start);
2678                         BUG_ON(!cache); /* Logic error */
2679
2680                         cluster = fetch_cluster_info(fs_info,
2681                                                      cache->space_info,
2682                                                      &empty_cluster);
2683                         empty_cluster <<= 1;
2684                 }
2685
2686                 len = cache->start + cache->length - start;
2687                 len = min(len, end + 1 - start);
2688
2689                 down_read(&fs_info->commit_root_sem);
2690                 if (start < cache->last_byte_to_unpin && return_free_space) {
2691                         u64 add_len = min(len, cache->last_byte_to_unpin - start);
2692
2693                         btrfs_add_free_space(cache, start, add_len);
2694                 }
2695                 up_read(&fs_info->commit_root_sem);
2696
2697                 start += len;
2698                 total_unpinned += len;
2699                 space_info = cache->space_info;
2700
2701                 /*
2702                  * If this space cluster has been marked as fragmented and we've
2703                  * unpinned enough in this block group to potentially allow a
2704                  * cluster to be created inside of it go ahead and clear the
2705                  * fragmented check.
2706                  */
2707                 if (cluster && cluster->fragmented &&
2708                     total_unpinned > empty_cluster) {
2709                         spin_lock(&cluster->lock);
2710                         cluster->fragmented = 0;
2711                         spin_unlock(&cluster->lock);
2712                 }
2713
2714                 spin_lock(&space_info->lock);
2715                 spin_lock(&cache->lock);
2716                 cache->pinned -= len;
2717                 btrfs_space_info_update_bytes_pinned(fs_info, space_info, -len);
2718                 space_info->max_extent_size = 0;
2719                 if (cache->ro) {
2720                         space_info->bytes_readonly += len;
2721                         readonly = true;
2722                 } else if (btrfs_is_zoned(fs_info)) {
2723                         /* Need reset before reusing in a zoned block group */
2724                         space_info->bytes_zone_unusable += len;
2725                         readonly = true;
2726                 }
2727                 spin_unlock(&cache->lock);
2728                 if (!readonly && return_free_space &&
2729                     global_rsv->space_info == space_info) {
2730                         spin_lock(&global_rsv->lock);
2731                         if (!global_rsv->full) {
2732                                 u64 to_add = min(len, global_rsv->size -
2733                                                       global_rsv->reserved);
2734
2735                                 global_rsv->reserved += to_add;
2736                                 btrfs_space_info_update_bytes_may_use(fs_info,
2737                                                 space_info, to_add);
2738                                 if (global_rsv->reserved >= global_rsv->size)
2739                                         global_rsv->full = 1;
2740                                 len -= to_add;
2741                         }
2742                         spin_unlock(&global_rsv->lock);
2743                 }
2744                 /* Add to any tickets we may have */
2745                 if (!readonly && return_free_space && len)
2746                         btrfs_try_granting_tickets(fs_info, space_info);
2747                 spin_unlock(&space_info->lock);
2748         }
2749
2750         if (cache)
2751                 btrfs_put_block_group(cache);
2752         return 0;
2753 }
2754
2755 int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans)
2756 {
2757         struct btrfs_fs_info *fs_info = trans->fs_info;
2758         struct btrfs_block_group *block_group, *tmp;
2759         struct list_head *deleted_bgs;
2760         struct extent_io_tree *unpin;
2761         u64 start;
2762         u64 end;
2763         int ret;
2764
2765         unpin = &trans->transaction->pinned_extents;
2766
2767         while (!TRANS_ABORTED(trans)) {
2768                 struct extent_state *cached_state = NULL;
2769
2770                 mutex_lock(&fs_info->unused_bg_unpin_mutex);
2771                 ret = find_first_extent_bit(unpin, 0, &start, &end,
2772                                             EXTENT_DIRTY, &cached_state);
2773                 if (ret) {
2774                         mutex_unlock(&fs_info->unused_bg_unpin_mutex);
2775                         break;
2776                 }
2777
2778                 if (btrfs_test_opt(fs_info, DISCARD_SYNC))
2779                         ret = btrfs_discard_extent(fs_info, start,
2780                                                    end + 1 - start, NULL);
2781
2782                 clear_extent_dirty(unpin, start, end, &cached_state);
2783                 unpin_extent_range(fs_info, start, end, true);
2784                 mutex_unlock(&fs_info->unused_bg_unpin_mutex);
2785                 free_extent_state(cached_state);
2786                 cond_resched();
2787         }
2788
2789         if (btrfs_test_opt(fs_info, DISCARD_ASYNC)) {
2790                 btrfs_discard_calc_delay(&fs_info->discard_ctl);
2791                 btrfs_discard_schedule_work(&fs_info->discard_ctl, true);
2792         }
2793
2794         /*
2795          * Transaction is finished.  We don't need the lock anymore.  We
2796          * do need to clean up the block groups in case of a transaction
2797          * abort.
2798          */
2799         deleted_bgs = &trans->transaction->deleted_bgs;
2800         list_for_each_entry_safe(block_group, tmp, deleted_bgs, bg_list) {
2801                 u64 trimmed = 0;
2802
2803                 ret = -EROFS;
2804                 if (!TRANS_ABORTED(trans))
2805                         ret = btrfs_discard_extent(fs_info,
2806                                                    block_group->start,
2807                                                    block_group->length,
2808                                                    &trimmed);
2809
2810                 list_del_init(&block_group->bg_list);
2811                 btrfs_unfreeze_block_group(block_group);
2812                 btrfs_put_block_group(block_group);
2813
2814                 if (ret) {
2815                         const char *errstr = btrfs_decode_error(ret);
2816                         btrfs_warn(fs_info,
2817                            "discard failed while removing blockgroup: errno=%d %s",
2818                                    ret, errstr);
2819                 }
2820         }
2821
2822         return 0;
2823 }
2824
2825 static int do_free_extent_accounting(struct btrfs_trans_handle *trans,
2826                                      u64 bytenr, u64 num_bytes, bool is_data)
2827 {
2828         int ret;
2829
2830         if (is_data) {
2831                 struct btrfs_root *csum_root;
2832
2833                 csum_root = btrfs_csum_root(trans->fs_info, bytenr);
2834                 ret = btrfs_del_csums(trans, csum_root, bytenr, num_bytes);
2835                 if (ret) {
2836                         btrfs_abort_transaction(trans, ret);
2837                         return ret;
2838                 }
2839         }
2840
2841         ret = add_to_free_space_tree(trans, bytenr, num_bytes);
2842         if (ret) {
2843                 btrfs_abort_transaction(trans, ret);
2844                 return ret;
2845         }
2846
2847         ret = btrfs_update_block_group(trans, bytenr, num_bytes, false);
2848         if (ret)
2849                 btrfs_abort_transaction(trans, ret);
2850
2851         return ret;
2852 }
2853
2854 /*
2855  * Drop one or more refs of @node.
2856  *
2857  * 1. Locate the extent refs.
2858  *    It's either inline in EXTENT/METADATA_ITEM or in keyed SHARED_* item.
2859  *    Locate it, then reduce the refs number or remove the ref line completely.
2860  *
2861  * 2. Update the refs count in EXTENT/METADATA_ITEM
2862  *
2863  * Inline backref case:
2864  *
2865  * in extent tree we have:
2866  *
2867  *      item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 16201 itemsize 82
2868  *              refs 2 gen 6 flags DATA
2869  *              extent data backref root FS_TREE objectid 258 offset 0 count 1
2870  *              extent data backref root FS_TREE objectid 257 offset 0 count 1
2871  *
2872  * This function gets called with:
2873  *
2874  *    node->bytenr = 13631488
2875  *    node->num_bytes = 1048576
2876  *    root_objectid = FS_TREE
2877  *    owner_objectid = 257
2878  *    owner_offset = 0
2879  *    refs_to_drop = 1
2880  *
2881  * Then we should get some like:
2882  *
2883  *      item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 16201 itemsize 82
2884  *              refs 1 gen 6 flags DATA
2885  *              extent data backref root FS_TREE objectid 258 offset 0 count 1
2886  *
2887  * Keyed backref case:
2888  *
2889  * in extent tree we have:
2890  *
2891  *      item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 3971 itemsize 24
2892  *              refs 754 gen 6 flags DATA
2893  *      [...]
2894  *      item 2 key (13631488 EXTENT_DATA_REF <HASH>) itemoff 3915 itemsize 28
2895  *              extent data backref root FS_TREE objectid 866 offset 0 count 1
2896  *
2897  * This function get called with:
2898  *
2899  *    node->bytenr = 13631488
2900  *    node->num_bytes = 1048576
2901  *    root_objectid = FS_TREE
2902  *    owner_objectid = 866
2903  *    owner_offset = 0
2904  *    refs_to_drop = 1
2905  *
2906  * Then we should get some like:
2907  *
2908  *      item 0 key (13631488 EXTENT_ITEM 1048576) itemoff 3971 itemsize 24
2909  *              refs 753 gen 6 flags DATA
2910  *
2911  * And that (13631488 EXTENT_DATA_REF <HASH>) gets removed.
2912  */
2913 static int __btrfs_free_extent(struct btrfs_trans_handle *trans,
2914                                struct btrfs_delayed_ref_node *node, u64 parent,
2915                                u64 root_objectid, u64 owner_objectid,
2916                                u64 owner_offset, int refs_to_drop,
2917                                struct btrfs_delayed_extent_op *extent_op)
2918 {
2919         struct btrfs_fs_info *info = trans->fs_info;
2920         struct btrfs_key key;
2921         struct btrfs_path *path;
2922         struct btrfs_root *extent_root;
2923         struct extent_buffer *leaf;
2924         struct btrfs_extent_item *ei;
2925         struct btrfs_extent_inline_ref *iref;
2926         int ret;
2927         int is_data;
2928         int extent_slot = 0;
2929         int found_extent = 0;
2930         int num_to_del = 1;
2931         u32 item_size;
2932         u64 refs;
2933         u64 bytenr = node->bytenr;
2934         u64 num_bytes = node->num_bytes;
2935         bool skinny_metadata = btrfs_fs_incompat(info, SKINNY_METADATA);
2936
2937         extent_root = btrfs_extent_root(info, bytenr);
2938         ASSERT(extent_root);
2939
2940         path = btrfs_alloc_path();
2941         if (!path)
2942                 return -ENOMEM;
2943
2944         is_data = owner_objectid >= BTRFS_FIRST_FREE_OBJECTID;
2945
2946         if (!is_data && refs_to_drop != 1) {
2947                 btrfs_crit(info,
2948 "invalid refs_to_drop, dropping more than 1 refs for tree block %llu refs_to_drop %u",
2949                            node->bytenr, refs_to_drop);
2950                 ret = -EINVAL;
2951                 btrfs_abort_transaction(trans, ret);
2952                 goto out;
2953         }
2954
2955         if (is_data)
2956                 skinny_metadata = false;
2957
2958         ret = lookup_extent_backref(trans, path, &iref, bytenr, num_bytes,
2959                                     parent, root_objectid, owner_objectid,
2960                                     owner_offset);
2961         if (ret == 0) {
2962                 /*
2963                  * Either the inline backref or the SHARED_DATA_REF/
2964                  * SHARED_BLOCK_REF is found
2965                  *
2966                  * Here is a quick path to locate EXTENT/METADATA_ITEM.
2967                  * It's possible the EXTENT/METADATA_ITEM is near current slot.
2968                  */
2969                 extent_slot = path->slots[0];
2970                 while (extent_slot >= 0) {
2971                         btrfs_item_key_to_cpu(path->nodes[0], &key,
2972                                               extent_slot);
2973                         if (key.objectid != bytenr)
2974                                 break;
2975                         if (key.type == BTRFS_EXTENT_ITEM_KEY &&
2976                             key.offset == num_bytes) {
2977                                 found_extent = 1;
2978                                 break;
2979                         }
2980                         if (key.type == BTRFS_METADATA_ITEM_KEY &&
2981                             key.offset == owner_objectid) {
2982                                 found_extent = 1;
2983                                 break;
2984                         }
2985
2986                         /* Quick path didn't find the EXTEMT/METADATA_ITEM */
2987                         if (path->slots[0] - extent_slot > 5)
2988                                 break;
2989                         extent_slot--;
2990                 }
2991
2992                 if (!found_extent) {
2993                         if (iref) {
2994                                 btrfs_crit(info,
2995 "invalid iref, no EXTENT/METADATA_ITEM found but has inline extent ref");
2996                                 btrfs_abort_transaction(trans, -EUCLEAN);
2997                                 goto err_dump;
2998                         }
2999                         /* Must be SHARED_* item, remove the backref first */
3000                         ret = remove_extent_backref(trans, extent_root, path,
3001                                                     NULL, refs_to_drop, is_data);
3002                         if (ret) {
3003                                 btrfs_abort_transaction(trans, ret);
3004                                 goto out;
3005                         }
3006                         btrfs_release_path(path);
3007
3008                         /* Slow path to locate EXTENT/METADATA_ITEM */
3009                         key.objectid = bytenr;
3010                         key.type = BTRFS_EXTENT_ITEM_KEY;
3011                         key.offset = num_bytes;
3012
3013                         if (!is_data && skinny_metadata) {
3014                                 key.type = BTRFS_METADATA_ITEM_KEY;
3015                                 key.offset = owner_objectid;
3016                         }
3017
3018                         ret = btrfs_search_slot(trans, extent_root,
3019                                                 &key, path, -1, 1);
3020                         if (ret > 0 && skinny_metadata && path->slots[0]) {
3021                                 /*
3022                                  * Couldn't find our skinny metadata item,
3023                                  * see if we have ye olde extent item.
3024                                  */
3025                                 path->slots[0]--;
3026                                 btrfs_item_key_to_cpu(path->nodes[0], &key,
3027                                                       path->slots[0]);
3028                                 if (key.objectid == bytenr &&
3029                                     key.type == BTRFS_EXTENT_ITEM_KEY &&
3030                                     key.offset == num_bytes)
3031                                         ret = 0;
3032                         }
3033
3034                         if (ret > 0 && skinny_metadata) {
3035                                 skinny_metadata = false;
3036                                 key.objectid = bytenr;
3037                                 key.type = BTRFS_EXTENT_ITEM_KEY;
3038                                 key.offset = num_bytes;
3039                                 btrfs_release_path(path);
3040                                 ret = btrfs_search_slot(trans, extent_root,
3041                                                         &key, path, -1, 1);
3042                         }
3043
3044                         if (ret) {
3045                                 btrfs_err(info,
3046                                           "umm, got %d back from search, was looking for %llu",
3047                                           ret, bytenr);
3048                                 if (ret > 0)
3049                                         btrfs_print_leaf(path->nodes[0]);
3050                         }
3051                         if (ret < 0) {
3052                                 btrfs_abort_transaction(trans, ret);
3053                                 goto out;
3054                         }
3055                         extent_slot = path->slots[0];
3056                 }
3057         } else if (WARN_ON(ret == -ENOENT)) {
3058                 btrfs_print_leaf(path->nodes[0]);
3059                 btrfs_err(info,
3060                         "unable to find ref byte nr %llu parent %llu root %llu  owner %llu offset %llu",
3061                         bytenr, parent, root_objectid, owner_objectid,
3062                         owner_offset);
3063                 btrfs_abort_transaction(trans, ret);
3064                 goto out;
3065         } else {
3066                 btrfs_abort_transaction(trans, ret);
3067                 goto out;
3068         }
3069
3070         leaf = path->nodes[0];
3071         item_size = btrfs_item_size(leaf, extent_slot);
3072         if (unlikely(item_size < sizeof(*ei))) {
3073                 ret = -EINVAL;
3074                 btrfs_print_v0_err(info);
3075                 btrfs_abort_transaction(trans, ret);
3076                 goto out;
3077         }
3078         ei = btrfs_item_ptr(leaf, extent_slot,
3079                             struct btrfs_extent_item);
3080         if (owner_objectid < BTRFS_FIRST_FREE_OBJECTID &&
3081             key.type == BTRFS_EXTENT_ITEM_KEY) {
3082                 struct btrfs_tree_block_info *bi;
3083                 if (item_size < sizeof(*ei) + sizeof(*bi)) {
3084                         btrfs_crit(info,
3085 "invalid extent item size for key (%llu, %u, %llu) owner %llu, has %u expect >= %zu",
3086                                    key.objectid, key.type, key.offset,
3087                                    owner_objectid, item_size,
3088                                    sizeof(*ei) + sizeof(*bi));
3089                         btrfs_abort_transaction(trans, -EUCLEAN);
3090                         goto err_dump;
3091                 }
3092                 bi = (struct btrfs_tree_block_info *)(ei + 1);
3093                 WARN_ON(owner_objectid != btrfs_tree_block_level(leaf, bi));
3094         }
3095
3096         refs = btrfs_extent_refs(leaf, ei);
3097         if (refs < refs_to_drop) {
3098                 btrfs_crit(info,
3099                 "trying to drop %d refs but we only have %llu for bytenr %llu",
3100                           refs_to_drop, refs, bytenr);
3101                 btrfs_abort_transaction(trans, -EUCLEAN);
3102                 goto err_dump;
3103         }
3104         refs -= refs_to_drop;
3105
3106         if (refs > 0) {
3107                 if (extent_op)
3108                         __run_delayed_extent_op(extent_op, leaf, ei);
3109                 /*
3110                  * In the case of inline back ref, reference count will
3111                  * be updated by remove_extent_backref
3112                  */
3113                 if (iref) {
3114                         if (!found_extent) {
3115                                 btrfs_crit(info,
3116 "invalid iref, got inlined extent ref but no EXTENT/METADATA_ITEM found");
3117                                 btrfs_abort_transaction(trans, -EUCLEAN);
3118                                 goto err_dump;
3119                         }
3120                 } else {
3121                         btrfs_set_extent_refs(leaf, ei, refs);
3122                         btrfs_mark_buffer_dirty(leaf);
3123                 }
3124                 if (found_extent) {
3125                         ret = remove_extent_backref(trans, extent_root, path,
3126                                                     iref, refs_to_drop, is_data);
3127                         if (ret) {
3128                                 btrfs_abort_transaction(trans, ret);
3129                                 goto out;
3130                         }
3131                 }
3132         } else {
3133                 /* In this branch refs == 1 */
3134                 if (found_extent) {
3135                         if (is_data && refs_to_drop !=
3136                             extent_data_ref_count(path, iref)) {
3137                                 btrfs_crit(info,
3138                 "invalid refs_to_drop, current refs %u refs_to_drop %u",
3139                                            extent_data_ref_count(path, iref),
3140                                            refs_to_drop);
3141                                 btrfs_abort_transaction(trans, -EUCLEAN);
3142                                 goto err_dump;
3143                         }
3144                         if (iref) {
3145                                 if (path->slots[0] != extent_slot) {
3146                                         btrfs_crit(info,
3147 "invalid iref, extent item key (%llu %u %llu) doesn't have wanted iref",
3148                                                    key.objectid, key.type,
3149                                                    key.offset);
3150                                         btrfs_abort_transaction(trans, -EUCLEAN);
3151                                         goto err_dump;
3152                                 }
3153                         } else {
3154                                 /*
3155                                  * No inline ref, we must be at SHARED_* item,
3156                                  * And it's single ref, it must be:
3157                                  * |    extent_slot       ||extent_slot + 1|
3158                                  * [ EXTENT/METADATA_ITEM ][ SHARED_* ITEM ]
3159                                  */
3160                                 if (path->slots[0] != extent_slot + 1) {
3161                                         btrfs_crit(info,
3162         "invalid SHARED_* item, previous item is not EXTENT/METADATA_ITEM");
3163                                         btrfs_abort_transaction(trans, -EUCLEAN);
3164                                         goto err_dump;
3165                                 }
3166                                 path->slots[0] = extent_slot;
3167                                 num_to_del = 2;
3168                         }
3169                 }
3170
3171                 ret = btrfs_del_items(trans, extent_root, path, path->slots[0],
3172                                       num_to_del);
3173                 if (ret) {
3174                         btrfs_abort_transaction(trans, ret);
3175                         goto out;
3176                 }
3177                 btrfs_release_path(path);
3178
3179                 ret = do_free_extent_accounting(trans, bytenr, num_bytes, is_data);
3180         }
3181         btrfs_release_path(path);
3182
3183 out:
3184         btrfs_free_path(path);
3185         return ret;
3186 err_dump:
3187         /*
3188          * Leaf dump can take up a lot of log buffer, so we only do full leaf
3189          * dump for debug build.
3190          */
3191         if (IS_ENABLED(CONFIG_BTRFS_DEBUG)) {
3192                 btrfs_crit(info, "path->slots[0]=%d extent_slot=%d",
3193                            path->slots[0], extent_slot);
3194                 btrfs_print_leaf(path->nodes[0]);
3195         }
3196
3197         btrfs_free_path(path);
3198         return -EUCLEAN;
3199 }
3200
3201 /*
3202  * when we free an block, it is possible (and likely) that we free the last
3203  * delayed ref for that extent as well.  This searches the delayed ref tree for
3204  * a given extent, and if there are no other delayed refs to be processed, it
3205  * removes it from the tree.
3206  */
3207 static noinline int check_ref_cleanup(struct btrfs_trans_handle *trans,
3208                                       u64 bytenr)
3209 {
3210         struct btrfs_delayed_ref_head *head;
3211         struct btrfs_delayed_ref_root *delayed_refs;
3212         int ret = 0;
3213
3214         delayed_refs = &trans->transaction->delayed_refs;
3215         spin_lock(&delayed_refs->lock);
3216         head = btrfs_find_delayed_ref_head(delayed_refs, bytenr);
3217         if (!head)
3218                 goto out_delayed_unlock;
3219
3220         spin_lock(&head->lock);
3221         if (!RB_EMPTY_ROOT(&head->ref_tree.rb_root))
3222                 goto out;
3223
3224         if (cleanup_extent_op(head) != NULL)
3225                 goto out;
3226
3227         /*
3228          * waiting for the lock here would deadlock.  If someone else has it
3229          * locked they are already in the process of dropping it anyway
3230          */
3231         if (!mutex_trylock(&head->mutex))
3232                 goto out;
3233
3234         btrfs_delete_ref_head(delayed_refs, head);
3235         head->processing = 0;
3236
3237         spin_unlock(&head->lock);
3238         spin_unlock(&delayed_refs->lock);
3239
3240         BUG_ON(head->extent_op);
3241         if (head->must_insert_reserved)
3242                 ret = 1;
3243
3244         btrfs_cleanup_ref_head_accounting(trans->fs_info, delayed_refs, head);
3245         mutex_unlock(&head->mutex);
3246         btrfs_put_delayed_ref_head(head);
3247         return ret;
3248 out:
3249         spin_unlock(&head->lock);
3250
3251 out_delayed_unlock:
3252         spin_unlock(&delayed_refs->lock);
3253         return 0;
3254 }
3255
3256 void btrfs_free_tree_block(struct btrfs_trans_handle *trans,
3257                            u64 root_id,
3258                            struct extent_buffer *buf,
3259                            u64 parent, int last_ref)
3260 {
3261         struct btrfs_fs_info *fs_info = trans->fs_info;
3262         struct btrfs_ref generic_ref = { 0 };
3263         int ret;
3264
3265         btrfs_init_generic_ref(&generic_ref, BTRFS_DROP_DELAYED_REF,
3266                                buf->start, buf->len, parent);
3267         btrfs_init_tree_ref(&generic_ref, btrfs_header_level(buf),
3268                             root_id, 0, false);
3269
3270         if (root_id != BTRFS_TREE_LOG_OBJECTID) {
3271                 btrfs_ref_tree_mod(fs_info, &generic_ref);
3272                 ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, NULL);
3273                 BUG_ON(ret); /* -ENOMEM */
3274         }
3275
3276         if (last_ref && btrfs_header_generation(buf) == trans->transid) {
3277                 struct btrfs_block_group *cache;
3278                 bool must_pin = false;
3279
3280                 if (root_id != BTRFS_TREE_LOG_OBJECTID) {
3281                         ret = check_ref_cleanup(trans, buf->start);
3282                         if (!ret) {
3283                                 btrfs_redirty_list_add(trans->transaction, buf);
3284                                 goto out;
3285                         }
3286                 }
3287
3288                 cache = btrfs_lookup_block_group(fs_info, buf->start);
3289
3290                 if (btrfs_header_flag(buf, BTRFS_HEADER_FLAG_WRITTEN)) {
3291                         pin_down_extent(trans, cache, buf->start, buf->len, 1);
3292                         btrfs_put_block_group(cache);
3293                         goto out;
3294                 }
3295
3296                 /*
3297                  * If this is a leaf and there are tree mod log users, we may
3298                  * have recorded mod log operations that point to this leaf.
3299                  * So we must make sure no one reuses this leaf's extent before
3300                  * mod log operations are applied to a node, otherwise after
3301                  * rewinding a node using the mod log operations we get an
3302                  * inconsistent btree, as the leaf's extent may now be used as
3303                  * a node or leaf for another different btree.
3304                  * We are safe from races here because at this point no other
3305                  * node or root points to this extent buffer, so if after this
3306                  * check a new tree mod log user joins, it will not be able to
3307                  * find a node pointing to this leaf and record operations that
3308                  * point to this leaf.
3309                  */
3310                 if (btrfs_header_level(buf) == 0 &&
3311                     test_bit(BTRFS_FS_TREE_MOD_LOG_USERS, &fs_info->flags))
3312                         must_pin = true;
3313
3314                 if (must_pin || btrfs_is_zoned(fs_info)) {
3315                         btrfs_redirty_list_add(trans->transaction, buf);
3316                         pin_down_extent(trans, cache, buf->start, buf->len, 1);
3317                         btrfs_put_block_group(cache);
3318                         goto out;
3319                 }
3320
3321                 WARN_ON(test_bit(EXTENT_BUFFER_DIRTY, &buf->bflags));
3322
3323                 btrfs_add_free_space(cache, buf->start, buf->len);
3324                 btrfs_free_reserved_bytes(cache, buf->len, 0);
3325                 btrfs_put_block_group(cache);
3326                 trace_btrfs_reserved_extent_free(fs_info, buf->start, buf->len);
3327         }
3328 out:
3329         if (last_ref) {
3330                 /*
3331                  * Deleting the buffer, clear the corrupt flag since it doesn't
3332                  * matter anymore.
3333                  */
3334                 clear_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags);
3335         }
3336 }
3337
3338 /* Can return -ENOMEM */
3339 int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_ref *ref)
3340 {
3341         struct btrfs_fs_info *fs_info = trans->fs_info;
3342         int ret;
3343
3344         if (btrfs_is_testing(fs_info))
3345                 return 0;
3346
3347         /*
3348          * tree log blocks never actually go into the extent allocation
3349          * tree, just update pinning info and exit early.
3350          */
3351         if ((ref->type == BTRFS_REF_METADATA &&
3352              ref->tree_ref.owning_root == BTRFS_TREE_LOG_OBJECTID) ||
3353             (ref->type == BTRFS_REF_DATA &&
3354              ref->data_ref.owning_root == BTRFS_TREE_LOG_OBJECTID)) {
3355                 /* unlocks the pinned mutex */
3356                 btrfs_pin_extent(trans, ref->bytenr, ref->len, 1);
3357                 ret = 0;
3358         } else if (ref->type == BTRFS_REF_METADATA) {
3359                 ret = btrfs_add_delayed_tree_ref(trans, ref, NULL);
3360         } else {
3361                 ret = btrfs_add_delayed_data_ref(trans, ref, 0);
3362         }
3363
3364         if (!((ref->type == BTRFS_REF_METADATA &&
3365                ref->tree_ref.owning_root == BTRFS_TREE_LOG_OBJECTID) ||
3366               (ref->type == BTRFS_REF_DATA &&
3367                ref->data_ref.owning_root == BTRFS_TREE_LOG_OBJECTID)))
3368                 btrfs_ref_tree_mod(fs_info, ref);
3369
3370         return ret;
3371 }
3372
3373 enum btrfs_loop_type {
3374         LOOP_CACHING_NOWAIT,
3375         LOOP_CACHING_WAIT,
3376         LOOP_ALLOC_CHUNK,
3377         LOOP_NO_EMPTY_SIZE,
3378 };
3379
3380 static inline void
3381 btrfs_lock_block_group(struct btrfs_block_group *cache,
3382                        int delalloc)
3383 {
3384         if (delalloc)
3385                 down_read(&cache->data_rwsem);
3386 }
3387
3388 static inline void btrfs_grab_block_group(struct btrfs_block_group *cache,
3389                        int delalloc)
3390 {
3391         btrfs_get_block_group(cache);
3392         if (delalloc)
3393                 down_read(&cache->data_rwsem);
3394 }
3395
3396 static struct btrfs_block_group *btrfs_lock_cluster(
3397                    struct btrfs_block_group *block_group,
3398                    struct btrfs_free_cluster *cluster,
3399                    int delalloc)
3400         __acquires(&cluster->refill_lock)
3401 {
3402         struct btrfs_block_group *used_bg = NULL;
3403
3404         spin_lock(&cluster->refill_lock);
3405         while (1) {
3406                 used_bg = cluster->block_group;
3407                 if (!used_bg)
3408                         return NULL;
3409
3410                 if (used_bg == block_group)
3411                         return used_bg;
3412
3413                 btrfs_get_block_group(used_bg);
3414
3415                 if (!delalloc)
3416                         return used_bg;
3417
3418                 if (down_read_trylock(&used_bg->data_rwsem))
3419                         return used_bg;
3420
3421                 spin_unlock(&cluster->refill_lock);
3422
3423                 /* We should only have one-level nested. */
3424                 down_read_nested(&used_bg->data_rwsem, SINGLE_DEPTH_NESTING);
3425
3426                 spin_lock(&cluster->refill_lock);
3427                 if (used_bg == cluster->block_group)
3428                         return used_bg;
3429
3430                 up_read(&used_bg->data_rwsem);
3431                 btrfs_put_block_group(used_bg);
3432         }
3433 }
3434
3435 static inline void
3436 btrfs_release_block_group(struct btrfs_block_group *cache,
3437                          int delalloc)
3438 {
3439         if (delalloc)
3440                 up_read(&cache->data_rwsem);
3441         btrfs_put_block_group(cache);
3442 }
3443
3444 enum btrfs_extent_allocation_policy {
3445         BTRFS_EXTENT_ALLOC_CLUSTERED,
3446         BTRFS_EXTENT_ALLOC_ZONED,
3447 };
3448
3449 /*
3450  * Structure used internally for find_free_extent() function.  Wraps needed
3451  * parameters.
3452  */
3453 struct find_free_extent_ctl {
3454         /* Basic allocation info */
3455         u64 ram_bytes;
3456         u64 num_bytes;
3457         u64 min_alloc_size;
3458         u64 empty_size;
3459         u64 flags;
3460         int delalloc;
3461
3462         /* Where to start the search inside the bg */
3463         u64 search_start;
3464
3465         /* For clustered allocation */
3466         u64 empty_cluster;
3467         struct btrfs_free_cluster *last_ptr;
3468         bool use_cluster;
3469
3470         bool have_caching_bg;
3471         bool orig_have_caching_bg;
3472
3473         /* Allocation is called for tree-log */
3474         bool for_treelog;
3475
3476         /* Allocation is called for data relocation */
3477         bool for_data_reloc;
3478
3479         /* RAID index, converted from flags */
3480         int index;
3481
3482         /*
3483          * Current loop number, check find_free_extent_update_loop() for details
3484          */
3485         int loop;
3486
3487         /*
3488          * Whether we're refilling a cluster, if true we need to re-search
3489          * current block group but don't try to refill the cluster again.
3490          */
3491         bool retry_clustered;
3492
3493         /*
3494          * Whether we're updating free space cache, if true we need to re-search
3495          * current block group but don't try updating free space cache again.
3496          */
3497         bool retry_unclustered;
3498
3499         /* If current block group is cached */
3500         int cached;
3501
3502         /* Max contiguous hole found */
3503         u64 max_extent_size;
3504
3505         /* Total free space from free space cache, not always contiguous */
3506         u64 total_free_space;
3507
3508         /* Found result */
3509         u64 found_offset;
3510
3511         /* Hint where to start looking for an empty space */
3512         u64 hint_byte;
3513
3514         /* Allocation policy */
3515         enum btrfs_extent_allocation_policy policy;
3516 };
3517
3518
3519 /*
3520  * Helper function for find_free_extent().
3521  *
3522  * Return -ENOENT to inform caller that we need fallback to unclustered mode.
3523  * Return -EAGAIN to inform caller that we need to re-search this block group
3524  * Return >0 to inform caller that we find nothing
3525  * Return 0 means we have found a location and set ffe_ctl->found_offset.
3526  */
3527 static int find_free_extent_clustered(struct btrfs_block_group *bg,
3528                                       struct find_free_extent_ctl *ffe_ctl,
3529                                       struct btrfs_block_group **cluster_bg_ret)
3530 {
3531         struct btrfs_block_group *cluster_bg;
3532         struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
3533         u64 aligned_cluster;
3534         u64 offset;
3535         int ret;
3536
3537         cluster_bg = btrfs_lock_cluster(bg, last_ptr, ffe_ctl->delalloc);
3538         if (!cluster_bg)
3539                 goto refill_cluster;
3540         if (cluster_bg != bg && (cluster_bg->ro ||
3541             !block_group_bits(cluster_bg, ffe_ctl->flags)))
3542                 goto release_cluster;
3543
3544         offset = btrfs_alloc_from_cluster(cluster_bg, last_ptr,
3545                         ffe_ctl->num_bytes, cluster_bg->start,
3546                         &ffe_ctl->max_extent_size);
3547         if (offset) {
3548                 /* We have a block, we're done */
3549                 spin_unlock(&last_ptr->refill_lock);
3550                 trace_btrfs_reserve_extent_cluster(cluster_bg,
3551                                 ffe_ctl->search_start, ffe_ctl->num_bytes);
3552                 *cluster_bg_ret = cluster_bg;
3553                 ffe_ctl->found_offset = offset;
3554                 return 0;
3555         }
3556         WARN_ON(last_ptr->block_group != cluster_bg);
3557
3558 release_cluster:
3559         /*
3560          * If we are on LOOP_NO_EMPTY_SIZE, we can't set up a new clusters, so
3561          * lets just skip it and let the allocator find whatever block it can
3562          * find. If we reach this point, we will have tried the cluster
3563          * allocator plenty of times and not have found anything, so we are
3564          * likely way too fragmented for the clustering stuff to find anything.
3565          *
3566          * However, if the cluster is taken from the current block group,
3567          * release the cluster first, so that we stand a better chance of
3568          * succeeding in the unclustered allocation.
3569          */
3570         if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE && cluster_bg != bg) {
3571                 spin_unlock(&last_ptr->refill_lock);
3572                 btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
3573                 return -ENOENT;
3574         }
3575
3576         /* This cluster didn't work out, free it and start over */
3577         btrfs_return_cluster_to_free_space(NULL, last_ptr);
3578
3579         if (cluster_bg != bg)
3580                 btrfs_release_block_group(cluster_bg, ffe_ctl->delalloc);
3581
3582 refill_cluster:
3583         if (ffe_ctl->loop >= LOOP_NO_EMPTY_SIZE) {
3584                 spin_unlock(&last_ptr->refill_lock);
3585                 return -ENOENT;
3586         }
3587
3588         aligned_cluster = max_t(u64,
3589                         ffe_ctl->empty_cluster + ffe_ctl->empty_size,
3590                         bg->full_stripe_len);
3591         ret = btrfs_find_space_cluster(bg, last_ptr, ffe_ctl->search_start,
3592                         ffe_ctl->num_bytes, aligned_cluster);
3593         if (ret == 0) {
3594                 /* Now pull our allocation out of this cluster */
3595                 offset = btrfs_alloc_from_cluster(bg, last_ptr,
3596                                 ffe_ctl->num_bytes, ffe_ctl->search_start,
3597                                 &ffe_ctl->max_extent_size);
3598                 if (offset) {
3599                         /* We found one, proceed */
3600                         spin_unlock(&last_ptr->refill_lock);
3601                         trace_btrfs_reserve_extent_cluster(bg,
3602                                         ffe_ctl->search_start,
3603                                         ffe_ctl->num_bytes);
3604                         ffe_ctl->found_offset = offset;
3605                         return 0;
3606                 }
3607         } else if (!ffe_ctl->cached && ffe_ctl->loop > LOOP_CACHING_NOWAIT &&
3608                    !ffe_ctl->retry_clustered) {
3609                 spin_unlock(&last_ptr->refill_lock);
3610
3611                 ffe_ctl->retry_clustered = true;
3612                 btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
3613                                 ffe_ctl->empty_cluster + ffe_ctl->empty_size);
3614                 return -EAGAIN;
3615         }
3616         /*
3617          * At this point we either didn't find a cluster or we weren't able to
3618          * allocate a block from our cluster.  Free the cluster we've been
3619          * trying to use, and go to the next block group.
3620          */
3621         btrfs_return_cluster_to_free_space(NULL, last_ptr);
3622         spin_unlock(&last_ptr->refill_lock);
3623         return 1;
3624 }
3625
3626 /*
3627  * Return >0 to inform caller that we find nothing
3628  * Return 0 when we found an free extent and set ffe_ctrl->found_offset
3629  * Return -EAGAIN to inform caller that we need to re-search this block group
3630  */
3631 static int find_free_extent_unclustered(struct btrfs_block_group *bg,
3632                                         struct find_free_extent_ctl *ffe_ctl)
3633 {
3634         struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
3635         u64 offset;
3636
3637         /*
3638          * We are doing an unclustered allocation, set the fragmented flag so
3639          * we don't bother trying to setup a cluster again until we get more
3640          * space.
3641          */
3642         if (unlikely(last_ptr)) {
3643                 spin_lock(&last_ptr->lock);
3644                 last_ptr->fragmented = 1;
3645                 spin_unlock(&last_ptr->lock);
3646         }
3647         if (ffe_ctl->cached) {
3648                 struct btrfs_free_space_ctl *free_space_ctl;
3649
3650                 free_space_ctl = bg->free_space_ctl;
3651                 spin_lock(&free_space_ctl->tree_lock);
3652                 if (free_space_ctl->free_space <
3653                     ffe_ctl->num_bytes + ffe_ctl->empty_cluster +
3654                     ffe_ctl->empty_size) {
3655                         ffe_ctl->total_free_space = max_t(u64,
3656                                         ffe_ctl->total_free_space,
3657                                         free_space_ctl->free_space);
3658                         spin_unlock(&free_space_ctl->tree_lock);
3659                         return 1;
3660                 }
3661                 spin_unlock(&free_space_ctl->tree_lock);
3662         }
3663
3664         offset = btrfs_find_space_for_alloc(bg, ffe_ctl->search_start,
3665                         ffe_ctl->num_bytes, ffe_ctl->empty_size,
3666                         &ffe_ctl->max_extent_size);
3667
3668         /*
3669          * If we didn't find a chunk, and we haven't failed on this block group
3670          * before, and this block group is in the middle of caching and we are
3671          * ok with waiting, then go ahead and wait for progress to be made, and
3672          * set @retry_unclustered to true.
3673          *
3674          * If @retry_unclustered is true then we've already waited on this
3675          * block group once and should move on to the next block group.
3676          */
3677         if (!offset && !ffe_ctl->retry_unclustered && !ffe_ctl->cached &&
3678             ffe_ctl->loop > LOOP_CACHING_NOWAIT) {
3679                 btrfs_wait_block_group_cache_progress(bg, ffe_ctl->num_bytes +
3680                                                       ffe_ctl->empty_size);
3681                 ffe_ctl->retry_unclustered = true;
3682                 return -EAGAIN;
3683         } else if (!offset) {
3684                 return 1;
3685         }
3686         ffe_ctl->found_offset = offset;
3687         return 0;
3688 }
3689
3690 static int do_allocation_clustered(struct btrfs_block_group *block_group,
3691                                    struct find_free_extent_ctl *ffe_ctl,
3692                                    struct btrfs_block_group **bg_ret)
3693 {
3694         int ret;
3695
3696         /* We want to try and use the cluster allocator, so lets look there */
3697         if (ffe_ctl->last_ptr && ffe_ctl->use_cluster) {
3698                 ret = find_free_extent_clustered(block_group, ffe_ctl, bg_ret);
3699                 if (ret >= 0 || ret == -EAGAIN)
3700                         return ret;
3701                 /* ret == -ENOENT case falls through */
3702         }
3703
3704         return find_free_extent_unclustered(block_group, ffe_ctl);
3705 }
3706
3707 /*
3708  * Tree-log block group locking
3709  * ============================
3710  *
3711  * fs_info::treelog_bg_lock protects the fs_info::treelog_bg which
3712  * indicates the starting address of a block group, which is reserved only
3713  * for tree-log metadata.
3714  *
3715  * Lock nesting
3716  * ============
3717  *
3718  * space_info::lock
3719  *   block_group::lock
3720  *     fs_info::treelog_bg_lock
3721  */
3722
3723 /*
3724  * Simple allocator for sequential-only block group. It only allows sequential
3725  * allocation. No need to play with trees. This function also reserves the
3726  * bytes as in btrfs_add_reserved_bytes.
3727  */
3728 static int do_allocation_zoned(struct btrfs_block_group *block_group,
3729                                struct find_free_extent_ctl *ffe_ctl,
3730                                struct btrfs_block_group **bg_ret)
3731 {
3732         struct btrfs_fs_info *fs_info = block_group->fs_info;
3733         struct btrfs_space_info *space_info = block_group->space_info;
3734         struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3735         u64 start = block_group->start;
3736         u64 num_bytes = ffe_ctl->num_bytes;
3737         u64 avail;
3738         u64 bytenr = block_group->start;
3739         u64 log_bytenr;
3740         u64 data_reloc_bytenr;
3741         int ret = 0;
3742         bool skip = false;
3743
3744         ASSERT(btrfs_is_zoned(block_group->fs_info));
3745
3746         /*
3747          * Do not allow non-tree-log blocks in the dedicated tree-log block
3748          * group, and vice versa.
3749          */
3750         spin_lock(&fs_info->treelog_bg_lock);
3751         log_bytenr = fs_info->treelog_bg;
3752         if (log_bytenr && ((ffe_ctl->for_treelog && bytenr != log_bytenr) ||
3753                            (!ffe_ctl->for_treelog && bytenr == log_bytenr)))
3754                 skip = true;
3755         spin_unlock(&fs_info->treelog_bg_lock);
3756         if (skip)
3757                 return 1;
3758
3759         /*
3760          * Do not allow non-relocation blocks in the dedicated relocation block
3761          * group, and vice versa.
3762          */
3763         spin_lock(&fs_info->relocation_bg_lock);
3764         data_reloc_bytenr = fs_info->data_reloc_bg;
3765         if (data_reloc_bytenr &&
3766             ((ffe_ctl->for_data_reloc && bytenr != data_reloc_bytenr) ||
3767              (!ffe_ctl->for_data_reloc && bytenr == data_reloc_bytenr)))
3768                 skip = true;
3769         spin_unlock(&fs_info->relocation_bg_lock);
3770         if (skip)
3771                 return 1;
3772
3773         /* Check RO and no space case before trying to activate it */
3774         spin_lock(&block_group->lock);
3775         if (block_group->ro || btrfs_zoned_bg_is_full(block_group)) {
3776                 ret = 1;
3777                 /*
3778                  * May need to clear fs_info->{treelog,data_reloc}_bg.
3779                  * Return the error after taking the locks.
3780                  */
3781         }
3782         spin_unlock(&block_group->lock);
3783
3784         if (!ret && !btrfs_zone_activate(block_group)) {
3785                 ret = 1;
3786                 /*
3787                  * May need to clear fs_info->{treelog,data_reloc}_bg.
3788                  * Return the error after taking the locks.
3789                  */
3790         }
3791
3792         spin_lock(&space_info->lock);
3793         spin_lock(&block_group->lock);
3794         spin_lock(&fs_info->treelog_bg_lock);
3795         spin_lock(&fs_info->relocation_bg_lock);
3796
3797         if (ret)
3798                 goto out;
3799
3800         ASSERT(!ffe_ctl->for_treelog ||
3801                block_group->start == fs_info->treelog_bg ||
3802                fs_info->treelog_bg == 0);
3803         ASSERT(!ffe_ctl->for_data_reloc ||
3804                block_group->start == fs_info->data_reloc_bg ||
3805                fs_info->data_reloc_bg == 0);
3806
3807         if (block_group->ro || block_group->zoned_data_reloc_ongoing) {
3808                 ret = 1;
3809                 goto out;
3810         }
3811
3812         /*
3813          * Do not allow currently using block group to be tree-log dedicated
3814          * block group.
3815          */
3816         if (ffe_ctl->for_treelog && !fs_info->treelog_bg &&
3817             (block_group->used || block_group->reserved)) {
3818                 ret = 1;
3819                 goto out;
3820         }
3821
3822         /*
3823          * Do not allow currently used block group to be the data relocation
3824          * dedicated block group.
3825          */
3826         if (ffe_ctl->for_data_reloc && !fs_info->data_reloc_bg &&
3827             (block_group->used || block_group->reserved)) {
3828                 ret = 1;
3829                 goto out;
3830         }
3831
3832         WARN_ON_ONCE(block_group->alloc_offset > block_group->zone_capacity);
3833         avail = block_group->zone_capacity - block_group->alloc_offset;
3834         if (avail < num_bytes) {
3835                 if (ffe_ctl->max_extent_size < avail) {
3836                         /*
3837                          * With sequential allocator, free space is always
3838                          * contiguous
3839                          */
3840                         ffe_ctl->max_extent_size = avail;
3841                         ffe_ctl->total_free_space = avail;
3842                 }
3843                 ret = 1;
3844                 goto out;
3845         }
3846
3847         if (ffe_ctl->for_treelog && !fs_info->treelog_bg)
3848                 fs_info->treelog_bg = block_group->start;
3849
3850         if (ffe_ctl->for_data_reloc && !fs_info->data_reloc_bg)
3851                 fs_info->data_reloc_bg = block_group->start;
3852
3853         ffe_ctl->found_offset = start + block_group->alloc_offset;
3854         block_group->alloc_offset += num_bytes;
3855         spin_lock(&ctl->tree_lock);
3856         ctl->free_space -= num_bytes;
3857         spin_unlock(&ctl->tree_lock);
3858
3859         /*
3860          * We do not check if found_offset is aligned to stripesize. The
3861          * address is anyway rewritten when using zone append writing.
3862          */
3863
3864         ffe_ctl->search_start = ffe_ctl->found_offset;
3865
3866 out:
3867         if (ret && ffe_ctl->for_treelog)
3868                 fs_info->treelog_bg = 0;
3869         if (ret && ffe_ctl->for_data_reloc &&
3870             fs_info->data_reloc_bg == block_group->start) {
3871                 /*
3872                  * Do not allow further allocations from this block group.
3873                  * Compared to increasing the ->ro, setting the
3874                  * ->zoned_data_reloc_ongoing flag still allows nocow
3875                  *  writers to come in. See btrfs_inc_nocow_writers().
3876                  *
3877                  * We need to disable an allocation to avoid an allocation of
3878                  * regular (non-relocation data) extent. With mix of relocation
3879                  * extents and regular extents, we can dispatch WRITE commands
3880                  * (for relocation extents) and ZONE APPEND commands (for
3881                  * regular extents) at the same time to the same zone, which
3882                  * easily break the write pointer.
3883                  */
3884                 block_group->zoned_data_reloc_ongoing = 1;
3885                 fs_info->data_reloc_bg = 0;
3886         }
3887         spin_unlock(&fs_info->relocation_bg_lock);
3888         spin_unlock(&fs_info->treelog_bg_lock);
3889         spin_unlock(&block_group->lock);
3890         spin_unlock(&space_info->lock);
3891         return ret;
3892 }
3893
3894 static int do_allocation(struct btrfs_block_group *block_group,
3895                          struct find_free_extent_ctl *ffe_ctl,
3896                          struct btrfs_block_group **bg_ret)
3897 {
3898         switch (ffe_ctl->policy) {
3899         case BTRFS_EXTENT_ALLOC_CLUSTERED:
3900                 return do_allocation_clustered(block_group, ffe_ctl, bg_ret);
3901         case BTRFS_EXTENT_ALLOC_ZONED:
3902                 return do_allocation_zoned(block_group, ffe_ctl, bg_ret);
3903         default:
3904                 BUG();
3905         }
3906 }
3907
3908 static void release_block_group(struct btrfs_block_group *block_group,
3909                                 struct find_free_extent_ctl *ffe_ctl,
3910                                 int delalloc)
3911 {
3912         switch (ffe_ctl->policy) {
3913         case BTRFS_EXTENT_ALLOC_CLUSTERED:
3914                 ffe_ctl->retry_clustered = false;
3915                 ffe_ctl->retry_unclustered = false;
3916                 break;
3917         case BTRFS_EXTENT_ALLOC_ZONED:
3918                 /* Nothing to do */
3919                 break;
3920         default:
3921                 BUG();
3922         }
3923
3924         BUG_ON(btrfs_bg_flags_to_raid_index(block_group->flags) !=
3925                ffe_ctl->index);
3926         btrfs_release_block_group(block_group, delalloc);
3927 }
3928
3929 static void found_extent_clustered(struct find_free_extent_ctl *ffe_ctl,
3930                                    struct btrfs_key *ins)
3931 {
3932         struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
3933
3934         if (!ffe_ctl->use_cluster && last_ptr) {
3935                 spin_lock(&last_ptr->lock);
3936                 last_ptr->window_start = ins->objectid;
3937                 spin_unlock(&last_ptr->lock);
3938         }
3939 }
3940
3941 static void found_extent(struct find_free_extent_ctl *ffe_ctl,
3942                          struct btrfs_key *ins)
3943 {
3944         switch (ffe_ctl->policy) {
3945         case BTRFS_EXTENT_ALLOC_CLUSTERED:
3946                 found_extent_clustered(ffe_ctl, ins);
3947                 break;
3948         case BTRFS_EXTENT_ALLOC_ZONED:
3949                 /* Nothing to do */
3950                 break;
3951         default:
3952                 BUG();
3953         }
3954 }
3955
3956 static int can_allocate_chunk_zoned(struct btrfs_fs_info *fs_info,
3957                                     struct find_free_extent_ctl *ffe_ctl)
3958 {
3959         /* If we can activate new zone, just allocate a chunk and use it */
3960         if (btrfs_can_activate_zone(fs_info->fs_devices, ffe_ctl->flags))
3961                 return 0;
3962
3963         /*
3964          * We already reached the max active zones. Try to finish one block
3965          * group to make a room for a new block group. This is only possible
3966          * for a data block group because btrfs_zone_finish() may need to wait
3967          * for a running transaction which can cause a deadlock for metadata
3968          * allocation.
3969          */
3970         if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA) {
3971                 int ret = btrfs_zone_finish_one_bg(fs_info);
3972
3973                 if (ret == 1)
3974                         return 0;
3975                 else if (ret < 0)
3976                         return ret;
3977         }
3978
3979         /*
3980          * If we have enough free space left in an already active block group
3981          * and we can't activate any other zone now, do not allow allocating a
3982          * new chunk and let find_free_extent() retry with a smaller size.
3983          */
3984         if (ffe_ctl->max_extent_size >= ffe_ctl->min_alloc_size)
3985                 return -ENOSPC;
3986
3987         /*
3988          * Even min_alloc_size is not left in any block groups. Since we cannot
3989          * activate a new block group, allocating it may not help. Let's tell a
3990          * caller to try again and hope it progress something by writing some
3991          * parts of the region. That is only possible for data block groups,
3992          * where a part of the region can be written.
3993          */
3994         if (ffe_ctl->flags & BTRFS_BLOCK_GROUP_DATA)
3995                 return -EAGAIN;
3996
3997         /*
3998          * We cannot activate a new block group and no enough space left in any
3999          * block groups. So, allocating a new block group may not help. But,
4000          * there is nothing to do anyway, so let's go with it.
4001          */
4002         return 0;
4003 }
4004
4005 static int can_allocate_chunk(struct btrfs_fs_info *fs_info,
4006                               struct find_free_extent_ctl *ffe_ctl)
4007 {
4008         switch (ffe_ctl->policy) {
4009         case BTRFS_EXTENT_ALLOC_CLUSTERED:
4010                 return 0;
4011         case BTRFS_EXTENT_ALLOC_ZONED:
4012                 return can_allocate_chunk_zoned(fs_info, ffe_ctl);
4013         default:
4014                 BUG();
4015         }
4016 }
4017
4018 static int chunk_allocation_failed(struct find_free_extent_ctl *ffe_ctl)
4019 {
4020         switch (ffe_ctl->policy) {
4021         case BTRFS_EXTENT_ALLOC_CLUSTERED:
4022                 /*
4023                  * If we can't allocate a new chunk we've already looped through
4024                  * at least once, move on to the NO_EMPTY_SIZE case.
4025                  */
4026                 ffe_ctl->loop = LOOP_NO_EMPTY_SIZE;
4027                 return 0;
4028         case BTRFS_EXTENT_ALLOC_ZONED:
4029                 /* Give up here */
4030                 return -ENOSPC;
4031         default:
4032                 BUG();
4033         }
4034 }
4035
4036 /*
4037  * Return >0 means caller needs to re-search for free extent
4038  * Return 0 means we have the needed free extent.
4039  * Return <0 means we failed to locate any free extent.
4040  */
4041 static int find_free_extent_update_loop(struct btrfs_fs_info *fs_info,
4042                                         struct btrfs_key *ins,
4043                                         struct find_free_extent_ctl *ffe_ctl,
4044                                         bool full_search)
4045 {
4046         struct btrfs_root *root = fs_info->chunk_root;
4047         int ret;
4048
4049         if ((ffe_ctl->loop == LOOP_CACHING_NOWAIT) &&
4050             ffe_ctl->have_caching_bg && !ffe_ctl->orig_have_caching_bg)
4051                 ffe_ctl->orig_have_caching_bg = true;
4052
4053         if (ins->objectid) {
4054                 found_extent(ffe_ctl, ins);
4055                 return 0;
4056         }
4057
4058         if (ffe_ctl->loop >= LOOP_CACHING_WAIT && ffe_ctl->have_caching_bg)
4059                 return 1;
4060
4061         ffe_ctl->index++;
4062         if (ffe_ctl->index < BTRFS_NR_RAID_TYPES)
4063                 return 1;
4064
4065         /*
4066          * LOOP_CACHING_NOWAIT, search partially cached block groups, kicking
4067          *                      caching kthreads as we move along
4068          * LOOP_CACHING_WAIT, search everything, and wait if our bg is caching
4069          * LOOP_ALLOC_CHUNK, force a chunk allocation and try again
4070          * LOOP_NO_EMPTY_SIZE, set empty_size and empty_cluster to 0 and try
4071          *                     again
4072          */
4073         if (ffe_ctl->loop < LOOP_NO_EMPTY_SIZE) {
4074                 ffe_ctl->index = 0;
4075                 if (ffe_ctl->loop == LOOP_CACHING_NOWAIT) {
4076                         /*
4077                          * We want to skip the LOOP_CACHING_WAIT step if we
4078                          * don't have any uncached bgs and we've already done a
4079                          * full search through.
4080                          */
4081                         if (ffe_ctl->orig_have_caching_bg || !full_search)
4082                                 ffe_ctl->loop = LOOP_CACHING_WAIT;
4083                         else
4084                                 ffe_ctl->loop = LOOP_ALLOC_CHUNK;
4085                 } else {
4086                         ffe_ctl->loop++;
4087                 }
4088
4089                 if (ffe_ctl->loop == LOOP_ALLOC_CHUNK) {
4090                         struct btrfs_trans_handle *trans;
4091                         int exist = 0;
4092
4093                         /*Check if allocation policy allows to create a new chunk */
4094                         ret = can_allocate_chunk(fs_info, ffe_ctl);
4095                         if (ret)
4096                                 return ret;
4097
4098                         trans = current->journal_info;
4099                         if (trans)
4100                                 exist = 1;
4101                         else
4102                                 trans = btrfs_join_transaction(root);
4103
4104                         if (IS_ERR(trans)) {
4105                                 ret = PTR_ERR(trans);
4106                                 return ret;
4107                         }
4108
4109                         ret = btrfs_chunk_alloc(trans, ffe_ctl->flags,
4110                                                 CHUNK_ALLOC_FORCE_FOR_EXTENT);
4111
4112                         /* Do not bail out on ENOSPC since we can do more. */
4113                         if (ret == -ENOSPC)
4114                                 ret = chunk_allocation_failed(ffe_ctl);
4115                         else if (ret < 0)
4116                                 btrfs_abort_transaction(trans, ret);
4117                         else
4118                                 ret = 0;
4119                         if (!exist)
4120                                 btrfs_end_transaction(trans);
4121                         if (ret)
4122                                 return ret;
4123                 }
4124
4125                 if (ffe_ctl->loop == LOOP_NO_EMPTY_SIZE) {
4126                         if (ffe_ctl->policy != BTRFS_EXTENT_ALLOC_CLUSTERED)
4127                                 return -ENOSPC;
4128
4129                         /*
4130                          * Don't loop again if we already have no empty_size and
4131                          * no empty_cluster.
4132                          */
4133                         if (ffe_ctl->empty_size == 0 &&
4134                             ffe_ctl->empty_cluster == 0)
4135                                 return -ENOSPC;
4136                         ffe_ctl->empty_size = 0;
4137                         ffe_ctl->empty_cluster = 0;
4138                 }
4139                 return 1;
4140         }
4141         return -ENOSPC;
4142 }
4143
4144 static int prepare_allocation_clustered(struct btrfs_fs_info *fs_info,
4145                                         struct find_free_extent_ctl *ffe_ctl,
4146                                         struct btrfs_space_info *space_info,
4147                                         struct btrfs_key *ins)
4148 {
4149         /*
4150          * If our free space is heavily fragmented we may not be able to make
4151          * big contiguous allocations, so instead of doing the expensive search
4152          * for free space, simply return ENOSPC with our max_extent_size so we
4153          * can go ahead and search for a more manageable chunk.
4154          *
4155          * If our max_extent_size is large enough for our allocation simply
4156          * disable clustering since we will likely not be able to find enough
4157          * space to create a cluster and induce latency trying.
4158          */
4159         if (space_info->max_extent_size) {
4160                 spin_lock(&space_info->lock);
4161                 if (space_info->max_extent_size &&
4162                     ffe_ctl->num_bytes > space_info->max_extent_size) {
4163                         ins->offset = space_info->max_extent_size;
4164                         spin_unlock(&space_info->lock);
4165                         return -ENOSPC;
4166                 } else if (space_info->max_extent_size) {
4167                         ffe_ctl->use_cluster = false;
4168                 }
4169                 spin_unlock(&space_info->lock);
4170         }
4171
4172         ffe_ctl->last_ptr = fetch_cluster_info(fs_info, space_info,
4173                                                &ffe_ctl->empty_cluster);
4174         if (ffe_ctl->last_ptr) {
4175                 struct btrfs_free_cluster *last_ptr = ffe_ctl->last_ptr;
4176
4177                 spin_lock(&last_ptr->lock);
4178                 if (last_ptr->block_group)
4179                         ffe_ctl->hint_byte = last_ptr->window_start;
4180                 if (last_ptr->fragmented) {
4181                         /*
4182                          * We still set window_start so we can keep track of the
4183                          * last place we found an allocation to try and save
4184                          * some time.
4185                          */
4186                         ffe_ctl->hint_byte = last_ptr->window_start;
4187                         ffe_ctl->use_cluster = false;
4188                 }
4189                 spin_unlock(&last_ptr->lock);
4190         }
4191
4192         return 0;
4193 }
4194
4195 static int prepare_allocation(struct btrfs_fs_info *fs_info,
4196                               struct find_free_extent_ctl *ffe_ctl,
4197                               struct btrfs_space_info *space_info,
4198                               struct btrfs_key *ins)
4199 {
4200         switch (ffe_ctl->policy) {
4201         case BTRFS_EXTENT_ALLOC_CLUSTERED:
4202                 return prepare_allocation_clustered(fs_info, ffe_ctl,
4203                                                     space_info, ins);
4204         case BTRFS_EXTENT_ALLOC_ZONED:
4205                 if (ffe_ctl->for_treelog) {
4206                         spin_lock(&fs_info->treelog_bg_lock);
4207                         if (fs_info->treelog_bg)
4208                                 ffe_ctl->hint_byte = fs_info->treelog_bg;
4209                         spin_unlock(&fs_info->treelog_bg_lock);
4210                 }
4211                 if (ffe_ctl->for_data_reloc) {
4212                         spin_lock(&fs_info->relocation_bg_lock);
4213                         if (fs_info->data_reloc_bg)
4214                                 ffe_ctl->hint_byte = fs_info->data_reloc_bg;
4215                         spin_unlock(&fs_info->relocation_bg_lock);
4216                 }
4217                 return 0;
4218         default:
4219                 BUG();
4220         }
4221 }
4222
4223 /*
4224  * walks the btree of allocated extents and find a hole of a given size.
4225  * The key ins is changed to record the hole:
4226  * ins->objectid == start position
4227  * ins->flags = BTRFS_EXTENT_ITEM_KEY
4228  * ins->offset == the size of the hole.
4229  * Any available blocks before search_start are skipped.
4230  *
4231  * If there is no suitable free space, we will record the max size of
4232  * the free space extent currently.
4233  *
4234  * The overall logic and call chain:
4235  *
4236  * find_free_extent()
4237  * |- Iterate through all block groups
4238  * |  |- Get a valid block group
4239  * |  |- Try to do clustered allocation in that block group
4240  * |  |- Try to do unclustered allocation in that block group
4241  * |  |- Check if the result is valid
4242  * |  |  |- If valid, then exit
4243  * |  |- Jump to next block group
4244  * |
4245  * |- Push harder to find free extents
4246  *    |- If not found, re-iterate all block groups
4247  */
4248 static noinline int find_free_extent(struct btrfs_root *root,
4249                                      struct btrfs_key *ins,
4250                                      struct find_free_extent_ctl *ffe_ctl)
4251 {
4252         struct btrfs_fs_info *fs_info = root->fs_info;
4253         int ret = 0;
4254         int cache_block_group_error = 0;
4255         struct btrfs_block_group *block_group = NULL;
4256         struct btrfs_space_info *space_info;
4257         bool full_search = false;
4258
4259         WARN_ON(ffe_ctl->num_bytes < fs_info->sectorsize);
4260
4261         ffe_ctl->search_start = 0;
4262         /* For clustered allocation */
4263         ffe_ctl->empty_cluster = 0;
4264         ffe_ctl->last_ptr = NULL;
4265         ffe_ctl->use_cluster = true;
4266         ffe_ctl->have_caching_bg = false;
4267         ffe_ctl->orig_have_caching_bg = false;
4268         ffe_ctl->index = btrfs_bg_flags_to_raid_index(ffe_ctl->flags);
4269         ffe_ctl->loop = 0;
4270         /* For clustered allocation */
4271         ffe_ctl->retry_clustered = false;
4272         ffe_ctl->retry_unclustered = false;
4273         ffe_ctl->cached = 0;
4274         ffe_ctl->max_extent_size = 0;
4275         ffe_ctl->total_free_space = 0;
4276         ffe_ctl->found_offset = 0;
4277         ffe_ctl->policy = BTRFS_EXTENT_ALLOC_CLUSTERED;
4278
4279         if (btrfs_is_zoned(fs_info))
4280                 ffe_ctl->policy = BTRFS_EXTENT_ALLOC_ZONED;
4281
4282         ins->type = BTRFS_EXTENT_ITEM_KEY;
4283         ins->objectid = 0;
4284         ins->offset = 0;
4285
4286         trace_find_free_extent(root, ffe_ctl->num_bytes, ffe_ctl->empty_size,
4287                                ffe_ctl->flags);
4288
4289         space_info = btrfs_find_space_info(fs_info, ffe_ctl->flags);
4290         if (!space_info) {
4291                 btrfs_err(fs_info, "No space info for %llu", ffe_ctl->flags);
4292                 return -ENOSPC;
4293         }
4294
4295         ret = prepare_allocation(fs_info, ffe_ctl, space_info, ins);
4296         if (ret < 0)
4297                 return ret;
4298
4299         ffe_ctl->search_start = max(ffe_ctl->search_start,
4300                                     first_logical_byte(fs_info));
4301         ffe_ctl->search_start = max(ffe_ctl->search_start, ffe_ctl->hint_byte);
4302         if (ffe_ctl->search_start == ffe_ctl->hint_byte) {
4303                 block_group = btrfs_lookup_block_group(fs_info,
4304                                                        ffe_ctl->search_start);
4305                 /*
4306                  * we don't want to use the block group if it doesn't match our
4307                  * allocation bits, or if its not cached.
4308                  *
4309                  * However if we are re-searching with an ideal block group
4310                  * picked out then we don't care that the block group is cached.
4311                  */
4312                 if (block_group && block_group_bits(block_group, ffe_ctl->flags) &&
4313                     block_group->cached != BTRFS_CACHE_NO) {
4314                         down_read(&space_info->groups_sem);
4315                         if (list_empty(&block_group->list) ||
4316                             block_group->ro) {
4317                                 /*
4318                                  * someone is removing this block group,
4319                                  * we can't jump into the have_block_group
4320                                  * target because our list pointers are not
4321                                  * valid
4322                                  */
4323                                 btrfs_put_block_group(block_group);
4324                                 up_read(&space_info->groups_sem);
4325                         } else {
4326                                 ffe_ctl->index = btrfs_bg_flags_to_raid_index(
4327                                                         block_group->flags);
4328                                 btrfs_lock_block_group(block_group,
4329                                                        ffe_ctl->delalloc);
4330                                 goto have_block_group;
4331                         }
4332                 } else if (block_group) {
4333                         btrfs_put_block_group(block_group);
4334                 }
4335         }
4336 search:
4337         ffe_ctl->have_caching_bg = false;
4338         if (ffe_ctl->index == btrfs_bg_flags_to_raid_index(ffe_ctl->flags) ||
4339             ffe_ctl->index == 0)
4340                 full_search = true;
4341         down_read(&space_info->groups_sem);
4342         list_for_each_entry(block_group,
4343                             &space_info->block_groups[ffe_ctl->index], list) {
4344                 struct btrfs_block_group *bg_ret;
4345
4346                 /* If the block group is read-only, we can skip it entirely. */
4347                 if (unlikely(block_group->ro)) {
4348                         if (ffe_ctl->for_treelog)
4349                                 btrfs_clear_treelog_bg(block_group);
4350                         if (ffe_ctl->for_data_reloc)
4351                                 btrfs_clear_data_reloc_bg(block_group);
4352                         continue;
4353                 }
4354
4355                 btrfs_grab_block_group(block_group, ffe_ctl->delalloc);
4356                 ffe_ctl->search_start = block_group->start;
4357
4358                 /*
4359                  * this can happen if we end up cycling through all the
4360                  * raid types, but we want to make sure we only allocate
4361                  * for the proper type.
4362                  */
4363                 if (!block_group_bits(block_group, ffe_ctl->flags)) {
4364                         u64 extra = BTRFS_BLOCK_GROUP_DUP |
4365                                 BTRFS_BLOCK_GROUP_RAID1_MASK |
4366                                 BTRFS_BLOCK_GROUP_RAID56_MASK |
4367                                 BTRFS_BLOCK_GROUP_RAID10;
4368
4369                         /*
4370                          * if they asked for extra copies and this block group
4371                          * doesn't provide them, bail.  This does allow us to
4372                          * fill raid0 from raid1.
4373                          */
4374                         if ((ffe_ctl->flags & extra) && !(block_group->flags & extra))
4375                                 goto loop;
4376
4377                         /*
4378                          * This block group has different flags than we want.
4379                          * It's possible that we have MIXED_GROUP flag but no
4380                          * block group is mixed.  Just skip such block group.
4381                          */
4382                         btrfs_release_block_group(block_group, ffe_ctl->delalloc);
4383                         continue;
4384                 }
4385
4386 have_block_group:
4387                 ffe_ctl->cached = btrfs_block_group_done(block_group);
4388                 if (unlikely(!ffe_ctl->cached)) {
4389                         ffe_ctl->have_caching_bg = true;
4390                         ret = btrfs_cache_block_group(block_group, false);
4391
4392                         /*
4393                          * If we get ENOMEM here or something else we want to
4394                          * try other block groups, because it may not be fatal.
4395                          * However if we can't find anything else we need to
4396                          * save our return here so that we return the actual
4397                          * error that caused problems, not ENOSPC.
4398                          */
4399                         if (ret < 0) {
4400                                 if (!cache_block_group_error)
4401                                         cache_block_group_error = ret;
4402                                 ret = 0;
4403                                 goto loop;
4404                         }
4405                         ret = 0;
4406                 }
4407
4408                 if (unlikely(block_group->cached == BTRFS_CACHE_ERROR))
4409                         goto loop;
4410
4411                 bg_ret = NULL;
4412                 ret = do_allocation(block_group, ffe_ctl, &bg_ret);
4413                 if (ret == 0) {
4414                         if (bg_ret && bg_ret != block_group) {
4415                                 btrfs_release_block_group(block_group,
4416                                                           ffe_ctl->delalloc);
4417                                 block_group = bg_ret;
4418                         }
4419                 } else if (ret == -EAGAIN) {
4420                         goto have_block_group;
4421                 } else if (ret > 0) {
4422                         goto loop;
4423                 }
4424
4425                 /* Checks */
4426                 ffe_ctl->search_start = round_up(ffe_ctl->found_offset,
4427                                                  fs_info->stripesize);
4428
4429                 /* move on to the next group */
4430                 if (ffe_ctl->search_start + ffe_ctl->num_bytes >
4431                     block_group->start + block_group->length) {
4432                         btrfs_add_free_space_unused(block_group,
4433                                             ffe_ctl->found_offset,
4434                                             ffe_ctl->num_bytes);
4435                         goto loop;
4436                 }
4437
4438                 if (ffe_ctl->found_offset < ffe_ctl->search_start)
4439                         btrfs_add_free_space_unused(block_group,
4440                                         ffe_ctl->found_offset,
4441                                         ffe_ctl->search_start - ffe_ctl->found_offset);
4442
4443                 ret = btrfs_add_reserved_bytes(block_group, ffe_ctl->ram_bytes,
4444                                                ffe_ctl->num_bytes,
4445                                                ffe_ctl->delalloc);
4446                 if (ret == -EAGAIN) {
4447                         btrfs_add_free_space_unused(block_group,
4448                                         ffe_ctl->found_offset,
4449                                         ffe_ctl->num_bytes);
4450                         goto loop;
4451                 }
4452                 btrfs_inc_block_group_reservations(block_group);
4453
4454                 /* we are all good, lets return */
4455                 ins->objectid = ffe_ctl->search_start;
4456                 ins->offset = ffe_ctl->num_bytes;
4457
4458                 trace_btrfs_reserve_extent(block_group, ffe_ctl->search_start,
4459                                            ffe_ctl->num_bytes);
4460                 btrfs_release_block_group(block_group, ffe_ctl->delalloc);
4461                 break;
4462 loop:
4463                 release_block_group(block_group, ffe_ctl, ffe_ctl->delalloc);
4464                 cond_resched();
4465         }
4466         up_read(&space_info->groups_sem);
4467
4468         ret = find_free_extent_update_loop(fs_info, ins, ffe_ctl, full_search);
4469         if (ret > 0)
4470                 goto search;
4471
4472         if (ret == -ENOSPC && !cache_block_group_error) {
4473                 /*
4474                  * Use ffe_ctl->total_free_space as fallback if we can't find
4475                  * any contiguous hole.
4476                  */
4477                 if (!ffe_ctl->max_extent_size)
4478                         ffe_ctl->max_extent_size = ffe_ctl->total_free_space;
4479                 spin_lock(&space_info->lock);
4480                 space_info->max_extent_size = ffe_ctl->max_extent_size;
4481                 spin_unlock(&space_info->lock);
4482                 ins->offset = ffe_ctl->max_extent_size;
4483         } else if (ret == -ENOSPC) {
4484                 ret = cache_block_group_error;
4485         }
4486         return ret;
4487 }
4488
4489 /*
4490  * btrfs_reserve_extent - entry point to the extent allocator. Tries to find a
4491  *                        hole that is at least as big as @num_bytes.
4492  *
4493  * @root           -    The root that will contain this extent
4494  *
4495  * @ram_bytes      -    The amount of space in ram that @num_bytes take. This
4496  *                      is used for accounting purposes. This value differs
4497  *                      from @num_bytes only in the case of compressed extents.
4498  *
4499  * @num_bytes      -    Number of bytes to allocate on-disk.
4500  *
4501  * @min_alloc_size -    Indicates the minimum amount of space that the
4502  *                      allocator should try to satisfy. In some cases
4503  *                      @num_bytes may be larger than what is required and if
4504  *                      the filesystem is fragmented then allocation fails.
4505  *                      However, the presence of @min_alloc_size gives a
4506  *                      chance to try and satisfy the smaller allocation.
4507  *
4508  * @empty_size     -    A hint that you plan on doing more COW. This is the
4509  *                      size in bytes the allocator should try to find free
4510  *                      next to the block it returns.  This is just a hint and
4511  *                      may be ignored by the allocator.
4512  *
4513  * @hint_byte      -    Hint to the allocator to start searching above the byte
4514  *                      address passed. It might be ignored.
4515  *
4516  * @ins            -    This key is modified to record the found hole. It will
4517  *                      have the following values:
4518  *                      ins->objectid == start position
4519  *                      ins->flags = BTRFS_EXTENT_ITEM_KEY
4520  *                      ins->offset == the size of the hole.
4521  *
4522  * @is_data        -    Boolean flag indicating whether an extent is
4523  *                      allocated for data (true) or metadata (false)
4524  *
4525  * @delalloc       -    Boolean flag indicating whether this allocation is for
4526  *                      delalloc or not. If 'true' data_rwsem of block groups
4527  *                      is going to be acquired.
4528  *
4529  *
4530  * Returns 0 when an allocation succeeded or < 0 when an error occurred. In
4531  * case -ENOSPC is returned then @ins->offset will contain the size of the
4532  * largest available hole the allocator managed to find.
4533  */
4534 int btrfs_reserve_extent(struct btrfs_root *root, u64 ram_bytes,
4535                          u64 num_bytes, u64 min_alloc_size,
4536                          u64 empty_size, u64 hint_byte,
4537                          struct btrfs_key *ins, int is_data, int delalloc)
4538 {
4539         struct btrfs_fs_info *fs_info = root->fs_info;
4540         struct find_free_extent_ctl ffe_ctl = {};
4541         bool final_tried = num_bytes == min_alloc_size;
4542         u64 flags;
4543         int ret;
4544         bool for_treelog = (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
4545         bool for_data_reloc = (btrfs_is_data_reloc_root(root) && is_data);
4546
4547         flags = get_alloc_profile_by_root(root, is_data);
4548 again:
4549         WARN_ON(num_bytes < fs_info->sectorsize);
4550
4551         ffe_ctl.ram_bytes = ram_bytes;
4552         ffe_ctl.num_bytes = num_bytes;
4553         ffe_ctl.min_alloc_size = min_alloc_size;
4554         ffe_ctl.empty_size = empty_size;
4555         ffe_ctl.flags = flags;
4556         ffe_ctl.delalloc = delalloc;
4557         ffe_ctl.hint_byte = hint_byte;
4558         ffe_ctl.for_treelog = for_treelog;
4559         ffe_ctl.for_data_reloc = for_data_reloc;
4560
4561         ret = find_free_extent(root, ins, &ffe_ctl);
4562         if (!ret && !is_data) {
4563                 btrfs_dec_block_group_reservations(fs_info, ins->objectid);
4564         } else if (ret == -ENOSPC) {
4565                 if (!final_tried && ins->offset) {
4566                         num_bytes = min(num_bytes >> 1, ins->offset);
4567                         num_bytes = round_down(num_bytes,
4568                                                fs_info->sectorsize);
4569                         num_bytes = max(num_bytes, min_alloc_size);
4570                         ram_bytes = num_bytes;
4571                         if (num_bytes == min_alloc_size)
4572                                 final_tried = true;
4573                         goto again;
4574                 } else if (btrfs_test_opt(fs_info, ENOSPC_DEBUG)) {
4575                         struct btrfs_space_info *sinfo;
4576
4577                         sinfo = btrfs_find_space_info(fs_info, flags);
4578                         btrfs_err(fs_info,
4579         "allocation failed flags %llu, wanted %llu tree-log %d, relocation: %d",
4580                                   flags, num_bytes, for_treelog, for_data_reloc);
4581                         if (sinfo)
4582                                 btrfs_dump_space_info(fs_info, sinfo,
4583                                                       num_bytes, 1);
4584                 }
4585         }
4586
4587         return ret;
4588 }
4589
4590 int btrfs_free_reserved_extent(struct btrfs_fs_info *fs_info,
4591                                u64 start, u64 len, int delalloc)
4592 {
4593         struct btrfs_block_group *cache;
4594
4595         cache = btrfs_lookup_block_group(fs_info, start);
4596         if (!cache) {
4597                 btrfs_err(fs_info, "Unable to find block group for %llu",
4598                           start);
4599                 return -ENOSPC;
4600         }
4601
4602         btrfs_add_free_space(cache, start, len);
4603         btrfs_free_reserved_bytes(cache, len, delalloc);
4604         trace_btrfs_reserved_extent_free(fs_info, start, len);
4605
4606         btrfs_put_block_group(cache);
4607         return 0;
4608 }
4609
4610 int btrfs_pin_reserved_extent(struct btrfs_trans_handle *trans, u64 start,
4611                               u64 len)
4612 {
4613         struct btrfs_block_group *cache;
4614         int ret = 0;
4615
4616         cache = btrfs_lookup_block_group(trans->fs_info, start);
4617         if (!cache) {
4618                 btrfs_err(trans->fs_info, "unable to find block group for %llu",
4619                           start);
4620                 return -ENOSPC;
4621         }
4622
4623         ret = pin_down_extent(trans, cache, start, len, 1);
4624         btrfs_put_block_group(cache);
4625         return ret;
4626 }
4627
4628 static int alloc_reserved_extent(struct btrfs_trans_handle *trans, u64 bytenr,
4629                                  u64 num_bytes)
4630 {
4631         struct btrfs_fs_info *fs_info = trans->fs_info;
4632         int ret;
4633
4634         ret = remove_from_free_space_tree(trans, bytenr, num_bytes);
4635         if (ret)
4636                 return ret;
4637
4638         ret = btrfs_update_block_group(trans, bytenr, num_bytes, true);
4639         if (ret) {
4640                 ASSERT(!ret);
4641                 btrfs_err(fs_info, "update block group failed for %llu %llu",
4642                           bytenr, num_bytes);
4643                 return ret;
4644         }
4645
4646         trace_btrfs_reserved_extent_alloc(fs_info, bytenr, num_bytes);
4647         return 0;
4648 }
4649
4650 static int alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
4651                                       u64 parent, u64 root_objectid,
4652                                       u64 flags, u64 owner, u64 offset,
4653                                       struct btrfs_key *ins, int ref_mod)
4654 {
4655         struct btrfs_fs_info *fs_info = trans->fs_info;
4656         struct btrfs_root *extent_root;
4657         int ret;
4658         struct btrfs_extent_item *extent_item;
4659         struct btrfs_extent_inline_ref *iref;
4660         struct btrfs_path *path;
4661         struct extent_buffer *leaf;
4662         int type;
4663         u32 size;
4664
4665         if (parent > 0)
4666                 type = BTRFS_SHARED_DATA_REF_KEY;
4667         else
4668                 type = BTRFS_EXTENT_DATA_REF_KEY;
4669
4670         size = sizeof(*extent_item) + btrfs_extent_inline_ref_size(type);
4671
4672         path = btrfs_alloc_path();
4673         if (!path)
4674                 return -ENOMEM;
4675
4676         extent_root = btrfs_extent_root(fs_info, ins->objectid);
4677         ret = btrfs_insert_empty_item(trans, extent_root, path, ins, size);
4678         if (ret) {
4679                 btrfs_free_path(path);
4680                 return ret;
4681         }
4682
4683         leaf = path->nodes[0];
4684         extent_item = btrfs_item_ptr(leaf, path->slots[0],
4685                                      struct btrfs_extent_item);
4686         btrfs_set_extent_refs(leaf, extent_item, ref_mod);
4687         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
4688         btrfs_set_extent_flags(leaf, extent_item,
4689                                flags | BTRFS_EXTENT_FLAG_DATA);
4690
4691         iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
4692         btrfs_set_extent_inline_ref_type(leaf, iref, type);
4693         if (parent > 0) {
4694                 struct btrfs_shared_data_ref *ref;
4695                 ref = (struct btrfs_shared_data_ref *)(iref + 1);
4696                 btrfs_set_extent_inline_ref_offset(leaf, iref, parent);
4697                 btrfs_set_shared_data_ref_count(leaf, ref, ref_mod);
4698         } else {
4699                 struct btrfs_extent_data_ref *ref;
4700                 ref = (struct btrfs_extent_data_ref *)(&iref->offset);
4701                 btrfs_set_extent_data_ref_root(leaf, ref, root_objectid);
4702                 btrfs_set_extent_data_ref_objectid(leaf, ref, owner);
4703                 btrfs_set_extent_data_ref_offset(leaf, ref, offset);
4704                 btrfs_set_extent_data_ref_count(leaf, ref, ref_mod);
4705         }
4706
4707         btrfs_mark_buffer_dirty(path->nodes[0]);
4708         btrfs_free_path(path);
4709
4710         return alloc_reserved_extent(trans, ins->objectid, ins->offset);
4711 }
4712
4713 static int alloc_reserved_tree_block(struct btrfs_trans_handle *trans,
4714                                      struct btrfs_delayed_ref_node *node,
4715                                      struct btrfs_delayed_extent_op *extent_op)
4716 {
4717         struct btrfs_fs_info *fs_info = trans->fs_info;
4718         struct btrfs_root *extent_root;
4719         int ret;
4720         struct btrfs_extent_item *extent_item;
4721         struct btrfs_key extent_key;
4722         struct btrfs_tree_block_info *block_info;
4723         struct btrfs_extent_inline_ref *iref;
4724         struct btrfs_path *path;
4725         struct extent_buffer *leaf;
4726         struct btrfs_delayed_tree_ref *ref;
4727         u32 size = sizeof(*extent_item) + sizeof(*iref);
4728         u64 flags = extent_op->flags_to_set;
4729         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
4730
4731         ref = btrfs_delayed_node_to_tree_ref(node);
4732
4733         extent_key.objectid = node->bytenr;
4734         if (skinny_metadata) {
4735                 extent_key.offset = ref->level;
4736                 extent_key.type = BTRFS_METADATA_ITEM_KEY;
4737         } else {
4738                 extent_key.offset = node->num_bytes;
4739                 extent_key.type = BTRFS_EXTENT_ITEM_KEY;
4740                 size += sizeof(*block_info);
4741         }
4742
4743         path = btrfs_alloc_path();
4744         if (!path)
4745                 return -ENOMEM;
4746
4747         extent_root = btrfs_extent_root(fs_info, extent_key.objectid);
4748         ret = btrfs_insert_empty_item(trans, extent_root, path, &extent_key,
4749                                       size);
4750         if (ret) {
4751                 btrfs_free_path(path);
4752                 return ret;
4753         }
4754
4755         leaf = path->nodes[0];
4756         extent_item = btrfs_item_ptr(leaf, path->slots[0],
4757                                      struct btrfs_extent_item);
4758         btrfs_set_extent_refs(leaf, extent_item, 1);
4759         btrfs_set_extent_generation(leaf, extent_item, trans->transid);
4760         btrfs_set_extent_flags(leaf, extent_item,
4761                                flags | BTRFS_EXTENT_FLAG_TREE_BLOCK);
4762
4763         if (skinny_metadata) {
4764                 iref = (struct btrfs_extent_inline_ref *)(extent_item + 1);
4765         } else {
4766                 block_info = (struct btrfs_tree_block_info *)(extent_item + 1);
4767                 btrfs_set_tree_block_key(leaf, block_info, &extent_op->key);
4768                 btrfs_set_tree_block_level(leaf, block_info, ref->level);
4769                 iref = (struct btrfs_extent_inline_ref *)(block_info + 1);
4770         }
4771
4772         if (node->type == BTRFS_SHARED_BLOCK_REF_KEY) {
4773                 btrfs_set_extent_inline_ref_type(leaf, iref,
4774                                                  BTRFS_SHARED_BLOCK_REF_KEY);
4775                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->parent);
4776         } else {
4777                 btrfs_set_extent_inline_ref_type(leaf, iref,
4778                                                  BTRFS_TREE_BLOCK_REF_KEY);
4779                 btrfs_set_extent_inline_ref_offset(leaf, iref, ref->root);
4780         }
4781
4782         btrfs_mark_buffer_dirty(leaf);
4783         btrfs_free_path(path);
4784
4785         return alloc_reserved_extent(trans, node->bytenr, fs_info->nodesize);
4786 }
4787
4788 int btrfs_alloc_reserved_file_extent(struct btrfs_trans_handle *trans,
4789                                      struct btrfs_root *root, u64 owner,
4790                                      u64 offset, u64 ram_bytes,
4791                                      struct btrfs_key *ins)
4792 {
4793         struct btrfs_ref generic_ref = { 0 };
4794
4795         BUG_ON(root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
4796
4797         btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
4798                                ins->objectid, ins->offset, 0);
4799         btrfs_init_data_ref(&generic_ref, root->root_key.objectid, owner,
4800                             offset, 0, false);
4801         btrfs_ref_tree_mod(root->fs_info, &generic_ref);
4802
4803         return btrfs_add_delayed_data_ref(trans, &generic_ref, ram_bytes);
4804 }
4805
4806 /*
4807  * this is used by the tree logging recovery code.  It records that
4808  * an extent has been allocated and makes sure to clear the free
4809  * space cache bits as well
4810  */
4811 int btrfs_alloc_logged_file_extent(struct btrfs_trans_handle *trans,
4812                                    u64 root_objectid, u64 owner, u64 offset,
4813                                    struct btrfs_key *ins)
4814 {
4815         struct btrfs_fs_info *fs_info = trans->fs_info;
4816         int ret;
4817         struct btrfs_block_group *block_group;
4818         struct btrfs_space_info *space_info;
4819
4820         /*
4821          * Mixed block groups will exclude before processing the log so we only
4822          * need to do the exclude dance if this fs isn't mixed.
4823          */
4824         if (!btrfs_fs_incompat(fs_info, MIXED_GROUPS)) {
4825                 ret = __exclude_logged_extent(fs_info, ins->objectid,
4826                                               ins->offset);
4827                 if (ret)
4828                         return ret;
4829         }
4830
4831         block_group = btrfs_lookup_block_group(fs_info, ins->objectid);
4832         if (!block_group)
4833                 return -EINVAL;
4834
4835         space_info = block_group->space_info;
4836         spin_lock(&space_info->lock);
4837         spin_lock(&block_group->lock);
4838         space_info->bytes_reserved += ins->offset;
4839         block_group->reserved += ins->offset;
4840         spin_unlock(&block_group->lock);
4841         spin_unlock(&space_info->lock);
4842
4843         ret = alloc_reserved_file_extent(trans, 0, root_objectid, 0, owner,
4844                                          offset, ins, 1);
4845         if (ret)
4846                 btrfs_pin_extent(trans, ins->objectid, ins->offset, 1);
4847         btrfs_put_block_group(block_group);
4848         return ret;
4849 }
4850
4851 static struct extent_buffer *
4852 btrfs_init_new_buffer(struct btrfs_trans_handle *trans, struct btrfs_root *root,
4853                       u64 bytenr, int level, u64 owner,
4854                       enum btrfs_lock_nesting nest)
4855 {
4856         struct btrfs_fs_info *fs_info = root->fs_info;
4857         struct extent_buffer *buf;
4858         u64 lockdep_owner = owner;
4859
4860         buf = btrfs_find_create_tree_block(fs_info, bytenr, owner, level);
4861         if (IS_ERR(buf))
4862                 return buf;
4863
4864         /*
4865          * Extra safety check in case the extent tree is corrupted and extent
4866          * allocator chooses to use a tree block which is already used and
4867          * locked.
4868          */
4869         if (buf->lock_owner == current->pid) {
4870                 btrfs_err_rl(fs_info,
4871 "tree block %llu owner %llu already locked by pid=%d, extent tree corruption detected",
4872                         buf->start, btrfs_header_owner(buf), current->pid);
4873                 free_extent_buffer(buf);
4874                 return ERR_PTR(-EUCLEAN);
4875         }
4876
4877         /*
4878          * The reloc trees are just snapshots, so we need them to appear to be
4879          * just like any other fs tree WRT lockdep.
4880          *
4881          * The exception however is in replace_path() in relocation, where we
4882          * hold the lock on the original fs root and then search for the reloc
4883          * root.  At that point we need to make sure any reloc root buffers are
4884          * set to the BTRFS_TREE_RELOC_OBJECTID lockdep class in order to make
4885          * lockdep happy.
4886          */
4887         if (lockdep_owner == BTRFS_TREE_RELOC_OBJECTID &&
4888             !test_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &root->state))
4889                 lockdep_owner = BTRFS_FS_TREE_OBJECTID;
4890
4891         /*
4892          * This needs to stay, because we could allocate a freed block from an
4893          * old tree into a new tree, so we need to make sure this new block is
4894          * set to the appropriate level and owner.
4895          */
4896         btrfs_set_buffer_lockdep_class(lockdep_owner, buf, level);
4897
4898         __btrfs_tree_lock(buf, nest);
4899         btrfs_clean_tree_block(buf);
4900         clear_bit(EXTENT_BUFFER_STALE, &buf->bflags);
4901         clear_bit(EXTENT_BUFFER_NO_CHECK, &buf->bflags);
4902
4903         set_extent_buffer_uptodate(buf);
4904
4905         memzero_extent_buffer(buf, 0, sizeof(struct btrfs_header));
4906         btrfs_set_header_level(buf, level);
4907         btrfs_set_header_bytenr(buf, buf->start);
4908         btrfs_set_header_generation(buf, trans->transid);
4909         btrfs_set_header_backref_rev(buf, BTRFS_MIXED_BACKREF_REV);
4910         btrfs_set_header_owner(buf, owner);
4911         write_extent_buffer_fsid(buf, fs_info->fs_devices->metadata_uuid);
4912         write_extent_buffer_chunk_tree_uuid(buf, fs_info->chunk_tree_uuid);
4913         if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
4914                 buf->log_index = root->log_transid % 2;
4915                 /*
4916                  * we allow two log transactions at a time, use different
4917                  * EXTENT bit to differentiate dirty pages.
4918                  */
4919                 if (buf->log_index == 0)
4920                         set_extent_dirty(&root->dirty_log_pages, buf->start,
4921                                         buf->start + buf->len - 1, GFP_NOFS);
4922                 else
4923                         set_extent_new(&root->dirty_log_pages, buf->start,
4924                                         buf->start + buf->len - 1);
4925         } else {
4926                 buf->log_index = -1;
4927                 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
4928                          buf->start + buf->len - 1, GFP_NOFS);
4929         }
4930         /* this returns a buffer locked for blocking */
4931         return buf;
4932 }
4933
4934 /*
4935  * finds a free extent and does all the dirty work required for allocation
4936  * returns the tree buffer or an ERR_PTR on error.
4937  */
4938 struct extent_buffer *btrfs_alloc_tree_block(struct btrfs_trans_handle *trans,
4939                                              struct btrfs_root *root,
4940                                              u64 parent, u64 root_objectid,
4941                                              const struct btrfs_disk_key *key,
4942                                              int level, u64 hint,
4943                                              u64 empty_size,
4944                                              enum btrfs_lock_nesting nest)
4945 {
4946         struct btrfs_fs_info *fs_info = root->fs_info;
4947         struct btrfs_key ins;
4948         struct btrfs_block_rsv *block_rsv;
4949         struct extent_buffer *buf;
4950         struct btrfs_delayed_extent_op *extent_op;
4951         struct btrfs_ref generic_ref = { 0 };
4952         u64 flags = 0;
4953         int ret;
4954         u32 blocksize = fs_info->nodesize;
4955         bool skinny_metadata = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
4956
4957 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4958         if (btrfs_is_testing(fs_info)) {
4959                 buf = btrfs_init_new_buffer(trans, root, root->alloc_bytenr,
4960                                             level, root_objectid, nest);
4961                 if (!IS_ERR(buf))
4962                         root->alloc_bytenr += blocksize;
4963                 return buf;
4964         }
4965 #endif
4966
4967         block_rsv = btrfs_use_block_rsv(trans, root, blocksize);
4968         if (IS_ERR(block_rsv))
4969                 return ERR_CAST(block_rsv);
4970
4971         ret = btrfs_reserve_extent(root, blocksize, blocksize, blocksize,
4972                                    empty_size, hint, &ins, 0, 0);
4973         if (ret)
4974                 goto out_unuse;
4975
4976         buf = btrfs_init_new_buffer(trans, root, ins.objectid, level,
4977                                     root_objectid, nest);
4978         if (IS_ERR(buf)) {
4979                 ret = PTR_ERR(buf);
4980                 goto out_free_reserved;
4981         }
4982
4983         if (root_objectid == BTRFS_TREE_RELOC_OBJECTID) {
4984                 if (parent == 0)
4985                         parent = ins.objectid;
4986                 flags |= BTRFS_BLOCK_FLAG_FULL_BACKREF;
4987         } else
4988                 BUG_ON(parent > 0);
4989
4990         if (root_objectid != BTRFS_TREE_LOG_OBJECTID) {
4991                 extent_op = btrfs_alloc_delayed_extent_op();
4992                 if (!extent_op) {
4993                         ret = -ENOMEM;
4994                         goto out_free_buf;
4995                 }
4996                 if (key)
4997                         memcpy(&extent_op->key, key, sizeof(extent_op->key));
4998                 else
4999                         memset(&extent_op->key, 0, sizeof(extent_op->key));
5000                 extent_op->flags_to_set = flags;
5001                 extent_op->update_key = skinny_metadata ? false : true;
5002                 extent_op->update_flags = true;
5003                 extent_op->level = level;
5004
5005                 btrfs_init_generic_ref(&generic_ref, BTRFS_ADD_DELAYED_EXTENT,
5006                                        ins.objectid, ins.offset, parent);
5007                 btrfs_init_tree_ref(&generic_ref, level, root_objectid,
5008                                     root->root_key.objectid, false);
5009                 btrfs_ref_tree_mod(fs_info, &generic_ref);
5010                 ret = btrfs_add_delayed_tree_ref(trans, &generic_ref, extent_op);
5011                 if (ret)
5012                         goto out_free_delayed;
5013         }
5014         return buf;
5015
5016 out_free_delayed:
5017         btrfs_free_delayed_extent_op(extent_op);
5018 out_free_buf:
5019         btrfs_tree_unlock(buf);
5020         free_extent_buffer(buf);
5021 out_free_reserved:
5022         btrfs_free_reserved_extent(fs_info, ins.objectid, ins.offset, 0);
5023 out_unuse:
5024         btrfs_unuse_block_rsv(fs_info, block_rsv, blocksize);
5025         return ERR_PTR(ret);
5026 }
5027
5028 struct walk_control {
5029         u64 refs[BTRFS_MAX_LEVEL];
5030         u64 flags[BTRFS_MAX_LEVEL];
5031         struct btrfs_key update_progress;
5032         struct btrfs_key drop_progress;
5033         int drop_level;
5034         int stage;
5035         int level;
5036         int shared_level;
5037         int update_ref;
5038         int keep_locks;
5039         int reada_slot;
5040         int reada_count;
5041         int restarted;
5042 };
5043
5044 #define DROP_REFERENCE  1
5045 #define UPDATE_BACKREF  2
5046
5047 static noinline void reada_walk_down(struct btrfs_trans_handle *trans,
5048                                      struct btrfs_root *root,
5049                                      struct walk_control *wc,
5050                                      struct btrfs_path *path)
5051 {
5052         struct btrfs_fs_info *fs_info = root->fs_info;
5053         u64 bytenr;
5054         u64 generation;
5055         u64 refs;
5056         u64 flags;
5057         u32 nritems;
5058         struct btrfs_key key;
5059         struct extent_buffer *eb;
5060         int ret;
5061         int slot;
5062         int nread = 0;
5063
5064         if (path->slots[wc->level] < wc->reada_slot) {
5065                 wc->reada_count = wc->reada_count * 2 / 3;
5066                 wc->reada_count = max(wc->reada_count, 2);
5067         } else {
5068                 wc->reada_count = wc->reada_count * 3 / 2;
5069                 wc->reada_count = min_t(int, wc->reada_count,
5070                                         BTRFS_NODEPTRS_PER_BLOCK(fs_info));
5071         }
5072
5073         eb = path->nodes[wc->level];
5074         nritems = btrfs_header_nritems(eb);
5075
5076         for (slot = path->slots[wc->level]; slot < nritems; slot++) {
5077                 if (nread >= wc->reada_count)
5078                         break;
5079
5080                 cond_resched();
5081                 bytenr = btrfs_node_blockptr(eb, slot);
5082                 generation = btrfs_node_ptr_generation(eb, slot);
5083
5084                 if (slot == path->slots[wc->level])
5085                         goto reada;
5086
5087                 if (wc->stage == UPDATE_BACKREF &&
5088                     generation <= root->root_key.offset)
5089                         continue;
5090
5091                 /* We don't lock the tree block, it's OK to be racy here */
5092                 ret = btrfs_lookup_extent_info(trans, fs_info, bytenr,
5093                                                wc->level - 1, 1, &refs,
5094                                                &flags);
5095                 /* We don't care about errors in readahead. */
5096                 if (ret < 0)
5097                         continue;
5098                 BUG_ON(refs == 0);
5099
5100                 if (wc->stage == DROP_REFERENCE) {
5101                         if (refs == 1)
5102                                 goto reada;
5103
5104                         if (wc->level == 1 &&
5105                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5106                                 continue;
5107                         if (!wc->update_ref ||
5108                             generation <= root->root_key.offset)
5109                                 continue;
5110                         btrfs_node_key_to_cpu(eb, &key, slot);
5111                         ret = btrfs_comp_cpu_keys(&key,
5112                                                   &wc->update_progress);
5113                         if (ret < 0)
5114                                 continue;
5115                 } else {
5116                         if (wc->level == 1 &&
5117                             (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5118                                 continue;
5119                 }
5120 reada:
5121                 btrfs_readahead_node_child(eb, slot);
5122                 nread++;
5123         }
5124         wc->reada_slot = slot;
5125 }
5126
5127 /*
5128  * helper to process tree block while walking down the tree.
5129  *
5130  * when wc->stage == UPDATE_BACKREF, this function updates
5131  * back refs for pointers in the block.
5132  *
5133  * NOTE: return value 1 means we should stop walking down.
5134  */
5135 static noinline int walk_down_proc(struct btrfs_trans_handle *trans,
5136                                    struct btrfs_root *root,
5137                                    struct btrfs_path *path,
5138                                    struct walk_control *wc, int lookup_info)
5139 {
5140         struct btrfs_fs_info *fs_info = root->fs_info;
5141         int level = wc->level;
5142         struct extent_buffer *eb = path->nodes[level];
5143         u64 flag = BTRFS_BLOCK_FLAG_FULL_BACKREF;
5144         int ret;
5145
5146         if (wc->stage == UPDATE_BACKREF &&
5147             btrfs_header_owner(eb) != root->root_key.objectid)
5148                 return 1;
5149
5150         /*
5151          * when reference count of tree block is 1, it won't increase
5152          * again. once full backref flag is set, we never clear it.
5153          */
5154         if (lookup_info &&
5155             ((wc->stage == DROP_REFERENCE && wc->refs[level] != 1) ||
5156              (wc->stage == UPDATE_BACKREF && !(wc->flags[level] & flag)))) {
5157                 BUG_ON(!path->locks[level]);
5158                 ret = btrfs_lookup_extent_info(trans, fs_info,
5159                                                eb->start, level, 1,
5160                                                &wc->refs[level],
5161                                                &wc->flags[level]);
5162                 BUG_ON(ret == -ENOMEM);
5163                 if (ret)
5164                         return ret;
5165                 BUG_ON(wc->refs[level] == 0);
5166         }
5167
5168         if (wc->stage == DROP_REFERENCE) {
5169                 if (wc->refs[level] > 1)
5170                         return 1;
5171
5172                 if (path->locks[level] && !wc->keep_locks) {
5173                         btrfs_tree_unlock_rw(eb, path->locks[level]);
5174                         path->locks[level] = 0;
5175                 }
5176                 return 0;
5177         }
5178
5179         /* wc->stage == UPDATE_BACKREF */
5180         if (!(wc->flags[level] & flag)) {
5181                 BUG_ON(!path->locks[level]);
5182                 ret = btrfs_inc_ref(trans, root, eb, 1);
5183                 BUG_ON(ret); /* -ENOMEM */
5184                 ret = btrfs_dec_ref(trans, root, eb, 0);
5185                 BUG_ON(ret); /* -ENOMEM */
5186                 ret = btrfs_set_disk_extent_flags(trans, eb, flag,
5187                                                   btrfs_header_level(eb));
5188                 BUG_ON(ret); /* -ENOMEM */
5189                 wc->flags[level] |= flag;
5190         }
5191
5192         /*
5193          * the block is shared by multiple trees, so it's not good to
5194          * keep the tree lock
5195          */
5196         if (path->locks[level] && level > 0) {
5197                 btrfs_tree_unlock_rw(eb, path->locks[level]);
5198                 path->locks[level] = 0;
5199         }
5200         return 0;
5201 }
5202
5203 /*
5204  * This is used to verify a ref exists for this root to deal with a bug where we
5205  * would have a drop_progress key that hadn't been updated properly.
5206  */
5207 static int check_ref_exists(struct btrfs_trans_handle *trans,
5208                             struct btrfs_root *root, u64 bytenr, u64 parent,
5209                             int level)
5210 {
5211         struct btrfs_path *path;
5212         struct btrfs_extent_inline_ref *iref;
5213         int ret;
5214
5215         path = btrfs_alloc_path();
5216         if (!path)
5217                 return -ENOMEM;
5218
5219         ret = lookup_extent_backref(trans, path, &iref, bytenr,
5220                                     root->fs_info->nodesize, parent,
5221                                     root->root_key.objectid, level, 0);
5222         btrfs_free_path(path);
5223         if (ret == -ENOENT)
5224                 return 0;
5225         if (ret < 0)
5226                 return ret;
5227         return 1;
5228 }
5229
5230 /*
5231  * helper to process tree block pointer.
5232  *
5233  * when wc->stage == DROP_REFERENCE, this function checks
5234  * reference count of the block pointed to. if the block
5235  * is shared and we need update back refs for the subtree
5236  * rooted at the block, this function changes wc->stage to
5237  * UPDATE_BACKREF. if the block is shared and there is no
5238  * need to update back, this function drops the reference
5239  * to the block.
5240  *
5241  * NOTE: return value 1 means we should stop walking down.
5242  */
5243 static noinline int do_walk_down(struct btrfs_trans_handle *trans,
5244                                  struct btrfs_root *root,
5245                                  struct btrfs_path *path,
5246                                  struct walk_control *wc, int *lookup_info)
5247 {
5248         struct btrfs_fs_info *fs_info = root->fs_info;
5249         u64 bytenr;
5250         u64 generation;
5251         u64 parent;
5252         struct btrfs_key key;
5253         struct btrfs_key first_key;
5254         struct btrfs_ref ref = { 0 };
5255         struct extent_buffer *next;
5256         int level = wc->level;
5257         int reada = 0;
5258         int ret = 0;
5259         bool need_account = false;
5260
5261         generation = btrfs_node_ptr_generation(path->nodes[level],
5262                                                path->slots[level]);
5263         /*
5264          * if the lower level block was created before the snapshot
5265          * was created, we know there is no need to update back refs
5266          * for the subtree
5267          */
5268         if (wc->stage == UPDATE_BACKREF &&
5269             generation <= root->root_key.offset) {
5270                 *lookup_info = 1;
5271                 return 1;
5272         }
5273
5274         bytenr = btrfs_node_blockptr(path->nodes[level], path->slots[level]);
5275         btrfs_node_key_to_cpu(path->nodes[level], &first_key,
5276                               path->slots[level]);
5277
5278         next = find_extent_buffer(fs_info, bytenr);
5279         if (!next) {
5280                 next = btrfs_find_create_tree_block(fs_info, bytenr,
5281                                 root->root_key.objectid, level - 1);
5282                 if (IS_ERR(next))
5283                         return PTR_ERR(next);
5284                 reada = 1;
5285         }
5286         btrfs_tree_lock(next);
5287
5288         ret = btrfs_lookup_extent_info(trans, fs_info, bytenr, level - 1, 1,
5289                                        &wc->refs[level - 1],
5290                                        &wc->flags[level - 1]);
5291         if (ret < 0)
5292                 goto out_unlock;
5293
5294         if (unlikely(wc->refs[level - 1] == 0)) {
5295                 btrfs_err(fs_info, "Missing references.");
5296                 ret = -EIO;
5297                 goto out_unlock;
5298         }
5299         *lookup_info = 0;
5300
5301         if (wc->stage == DROP_REFERENCE) {
5302                 if (wc->refs[level - 1] > 1) {
5303                         need_account = true;
5304                         if (level == 1 &&
5305                             (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5306                                 goto skip;
5307
5308                         if (!wc->update_ref ||
5309                             generation <= root->root_key.offset)
5310                                 goto skip;
5311
5312                         btrfs_node_key_to_cpu(path->nodes[level], &key,
5313                                               path->slots[level]);
5314                         ret = btrfs_comp_cpu_keys(&key, &wc->update_progress);
5315                         if (ret < 0)
5316                                 goto skip;
5317
5318                         wc->stage = UPDATE_BACKREF;
5319                         wc->shared_level = level - 1;
5320                 }
5321         } else {
5322                 if (level == 1 &&
5323                     (wc->flags[0] & BTRFS_BLOCK_FLAG_FULL_BACKREF))
5324                         goto skip;
5325         }
5326
5327         if (!btrfs_buffer_uptodate(next, generation, 0)) {
5328                 btrfs_tree_unlock(next);
5329                 free_extent_buffer(next);
5330                 next = NULL;
5331                 *lookup_info = 1;
5332         }
5333
5334         if (!next) {
5335                 if (reada && level == 1)
5336                         reada_walk_down(trans, root, wc, path);
5337                 next = read_tree_block(fs_info, bytenr, root->root_key.objectid,
5338                                        generation, level - 1, &first_key);
5339                 if (IS_ERR(next)) {
5340                         return PTR_ERR(next);
5341                 } else if (!extent_buffer_uptodate(next)) {
5342                         free_extent_buffer(next);
5343                         return -EIO;
5344                 }
5345                 btrfs_tree_lock(next);
5346         }
5347
5348         level--;
5349         ASSERT(level == btrfs_header_level(next));
5350         if (level != btrfs_header_level(next)) {
5351                 btrfs_err(root->fs_info, "mismatched level");
5352                 ret = -EIO;
5353                 goto out_unlock;
5354         }
5355         path->nodes[level] = next;
5356         path->slots[level] = 0;
5357         path->locks[level] = BTRFS_WRITE_LOCK;
5358         wc->level = level;
5359         if (wc->level == 1)
5360                 wc->reada_slot = 0;
5361         return 0;
5362 skip:
5363         wc->refs[level - 1] = 0;
5364         wc->flags[level - 1] = 0;
5365         if (wc->stage == DROP_REFERENCE) {
5366                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF) {
5367                         parent = path->nodes[level]->start;
5368                 } else {
5369                         ASSERT(root->root_key.objectid ==
5370                                btrfs_header_owner(path->nodes[level]));
5371                         if (root->root_key.objectid !=
5372                             btrfs_header_owner(path->nodes[level])) {
5373                                 btrfs_err(root->fs_info,
5374                                                 "mismatched block owner");
5375                                 ret = -EIO;
5376                                 goto out_unlock;
5377                         }
5378                         parent = 0;
5379                 }
5380
5381                 /*
5382                  * If we had a drop_progress we need to verify the refs are set
5383                  * as expected.  If we find our ref then we know that from here
5384                  * on out everything should be correct, and we can clear the
5385                  * ->restarted flag.
5386                  */
5387                 if (wc->restarted) {
5388                         ret = check_ref_exists(trans, root, bytenr, parent,
5389                                                level - 1);
5390                         if (ret < 0)
5391                                 goto out_unlock;
5392                         if (ret == 0)
5393                                 goto no_delete;
5394                         ret = 0;
5395                         wc->restarted = 0;
5396                 }
5397
5398                 /*
5399                  * Reloc tree doesn't contribute to qgroup numbers, and we have
5400                  * already accounted them at merge time (replace_path),
5401                  * thus we could skip expensive subtree trace here.
5402                  */
5403                 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
5404                     need_account) {
5405                         ret = btrfs_qgroup_trace_subtree(trans, next,
5406                                                          generation, level - 1);
5407                         if (ret) {
5408                                 btrfs_err_rl(fs_info,
5409                                              "Error %d accounting shared subtree. Quota is out of sync, rescan required.",
5410                                              ret);
5411                         }
5412                 }
5413
5414                 /*
5415                  * We need to update the next key in our walk control so we can
5416                  * update the drop_progress key accordingly.  We don't care if
5417                  * find_next_key doesn't find a key because that means we're at
5418                  * the end and are going to clean up now.
5419                  */
5420                 wc->drop_level = level;
5421                 find_next_key(path, level, &wc->drop_progress);
5422
5423                 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
5424                                        fs_info->nodesize, parent);
5425                 btrfs_init_tree_ref(&ref, level - 1, root->root_key.objectid,
5426                                     0, false);
5427                 ret = btrfs_free_extent(trans, &ref);
5428                 if (ret)
5429                         goto out_unlock;
5430         }
5431 no_delete:
5432         *lookup_info = 1;
5433         ret = 1;
5434
5435 out_unlock:
5436         btrfs_tree_unlock(next);
5437         free_extent_buffer(next);
5438
5439         return ret;
5440 }
5441
5442 /*
5443  * helper to process tree block while walking up the tree.
5444  *
5445  * when wc->stage == DROP_REFERENCE, this function drops
5446  * reference count on the block.
5447  *
5448  * when wc->stage == UPDATE_BACKREF, this function changes
5449  * wc->stage back to DROP_REFERENCE if we changed wc->stage
5450  * to UPDATE_BACKREF previously while processing the block.
5451  *
5452  * NOTE: return value 1 means we should stop walking up.
5453  */
5454 static noinline int walk_up_proc(struct btrfs_trans_handle *trans,
5455                                  struct btrfs_root *root,
5456                                  struct btrfs_path *path,
5457                                  struct walk_control *wc)
5458 {
5459         struct btrfs_fs_info *fs_info = root->fs_info;
5460         int ret;
5461         int level = wc->level;
5462         struct extent_buffer *eb = path->nodes[level];
5463         u64 parent = 0;
5464
5465         if (wc->stage == UPDATE_BACKREF) {
5466                 BUG_ON(wc->shared_level < level);
5467                 if (level < wc->shared_level)
5468                         goto out;
5469
5470                 ret = find_next_key(path, level + 1, &wc->update_progress);
5471                 if (ret > 0)
5472                         wc->update_ref = 0;
5473
5474                 wc->stage = DROP_REFERENCE;
5475                 wc->shared_level = -1;
5476                 path->slots[level] = 0;
5477
5478                 /*
5479                  * check reference count again if the block isn't locked.
5480                  * we should start walking down the tree again if reference
5481                  * count is one.
5482                  */
5483                 if (!path->locks[level]) {
5484                         BUG_ON(level == 0);
5485                         btrfs_tree_lock(eb);
5486                         path->locks[level] = BTRFS_WRITE_LOCK;
5487
5488                         ret = btrfs_lookup_extent_info(trans, fs_info,
5489                                                        eb->start, level, 1,
5490                                                        &wc->refs[level],
5491                                                        &wc->flags[level]);
5492                         if (ret < 0) {
5493                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
5494                                 path->locks[level] = 0;
5495                                 return ret;
5496                         }
5497                         BUG_ON(wc->refs[level] == 0);
5498                         if (wc->refs[level] == 1) {
5499                                 btrfs_tree_unlock_rw(eb, path->locks[level]);
5500                                 path->locks[level] = 0;
5501                                 return 1;
5502                         }
5503                 }
5504         }
5505
5506         /* wc->stage == DROP_REFERENCE */
5507         BUG_ON(wc->refs[level] > 1 && !path->locks[level]);
5508
5509         if (wc->refs[level] == 1) {
5510                 if (level == 0) {
5511                         if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5512                                 ret = btrfs_dec_ref(trans, root, eb, 1);
5513                         else
5514                                 ret = btrfs_dec_ref(trans, root, eb, 0);
5515                         BUG_ON(ret); /* -ENOMEM */
5516                         if (is_fstree(root->root_key.objectid)) {
5517                                 ret = btrfs_qgroup_trace_leaf_items(trans, eb);
5518                                 if (ret) {
5519                                         btrfs_err_rl(fs_info,
5520         "error %d accounting leaf items, quota is out of sync, rescan required",
5521                                              ret);
5522                                 }
5523                         }
5524                 }
5525                 /* make block locked assertion in btrfs_clean_tree_block happy */
5526                 if (!path->locks[level] &&
5527                     btrfs_header_generation(eb) == trans->transid) {
5528                         btrfs_tree_lock(eb);
5529                         path->locks[level] = BTRFS_WRITE_LOCK;
5530                 }
5531                 btrfs_clean_tree_block(eb);
5532         }
5533
5534         if (eb == root->node) {
5535                 if (wc->flags[level] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5536                         parent = eb->start;
5537                 else if (root->root_key.objectid != btrfs_header_owner(eb))
5538                         goto owner_mismatch;
5539         } else {
5540                 if (wc->flags[level + 1] & BTRFS_BLOCK_FLAG_FULL_BACKREF)
5541                         parent = path->nodes[level + 1]->start;
5542                 else if (root->root_key.objectid !=
5543                          btrfs_header_owner(path->nodes[level + 1]))
5544                         goto owner_mismatch;
5545         }
5546
5547         btrfs_free_tree_block(trans, btrfs_root_id(root), eb, parent,
5548                               wc->refs[level] == 1);
5549 out:
5550         wc->refs[level] = 0;
5551         wc->flags[level] = 0;
5552         return 0;
5553
5554 owner_mismatch:
5555         btrfs_err_rl(fs_info, "unexpected tree owner, have %llu expect %llu",
5556                      btrfs_header_owner(eb), root->root_key.objectid);
5557         return -EUCLEAN;
5558 }
5559
5560 static noinline int walk_down_tree(struct btrfs_trans_handle *trans,
5561                                    struct btrfs_root *root,
5562                                    struct btrfs_path *path,
5563                                    struct walk_control *wc)
5564 {
5565         int level = wc->level;
5566         int lookup_info = 1;
5567         int ret;
5568
5569         while (level >= 0) {
5570                 ret = walk_down_proc(trans, root, path, wc, lookup_info);
5571                 if (ret > 0)
5572                         break;
5573
5574                 if (level == 0)
5575                         break;
5576
5577                 if (path->slots[level] >=
5578                     btrfs_header_nritems(path->nodes[level]))
5579                         break;
5580
5581                 ret = do_walk_down(trans, root, path, wc, &lookup_info);
5582                 if (ret > 0) {
5583                         path->slots[level]++;
5584                         continue;
5585                 } else if (ret < 0)
5586                         return ret;
5587                 level = wc->level;
5588         }
5589         return 0;
5590 }
5591
5592 static noinline int walk_up_tree(struct btrfs_trans_handle *trans,
5593                                  struct btrfs_root *root,
5594                                  struct btrfs_path *path,
5595                                  struct walk_control *wc, int max_level)
5596 {
5597         int level = wc->level;
5598         int ret;
5599
5600         path->slots[level] = btrfs_header_nritems(path->nodes[level]);
5601         while (level < max_level && path->nodes[level]) {
5602                 wc->level = level;
5603                 if (path->slots[level] + 1 <
5604                     btrfs_header_nritems(path->nodes[level])) {
5605                         path->slots[level]++;
5606                         return 0;
5607                 } else {
5608                         ret = walk_up_proc(trans, root, path, wc);
5609                         if (ret > 0)
5610                                 return 0;
5611                         if (ret < 0)
5612                                 return ret;
5613
5614                         if (path->locks[level]) {
5615                                 btrfs_tree_unlock_rw(path->nodes[level],
5616                                                      path->locks[level]);
5617                                 path->locks[level] = 0;
5618                         }
5619                         free_extent_buffer(path->nodes[level]);
5620                         path->nodes[level] = NULL;
5621                         level++;
5622                 }
5623         }
5624         return 1;
5625 }
5626
5627 /*
5628  * drop a subvolume tree.
5629  *
5630  * this function traverses the tree freeing any blocks that only
5631  * referenced by the tree.
5632  *
5633  * when a shared tree block is found. this function decreases its
5634  * reference count by one. if update_ref is true, this function
5635  * also make sure backrefs for the shared block and all lower level
5636  * blocks are properly updated.
5637  *
5638  * If called with for_reloc == 0, may exit early with -EAGAIN
5639  */
5640 int btrfs_drop_snapshot(struct btrfs_root *root, int update_ref, int for_reloc)
5641 {
5642         struct btrfs_fs_info *fs_info = root->fs_info;
5643         struct btrfs_path *path;
5644         struct btrfs_trans_handle *trans;
5645         struct btrfs_root *tree_root = fs_info->tree_root;
5646         struct btrfs_root_item *root_item = &root->root_item;
5647         struct walk_control *wc;
5648         struct btrfs_key key;
5649         int err = 0;
5650         int ret;
5651         int level;
5652         bool root_dropped = false;
5653         bool unfinished_drop = false;
5654
5655         btrfs_debug(fs_info, "Drop subvolume %llu", root->root_key.objectid);
5656
5657         path = btrfs_alloc_path();
5658         if (!path) {
5659                 err = -ENOMEM;
5660                 goto out;
5661         }
5662
5663         wc = kzalloc(sizeof(*wc), GFP_NOFS);
5664         if (!wc) {
5665                 btrfs_free_path(path);
5666                 err = -ENOMEM;
5667                 goto out;
5668         }
5669
5670         /*
5671          * Use join to avoid potential EINTR from transaction start. See
5672          * wait_reserve_ticket and the whole reservation callchain.
5673          */
5674         if (for_reloc)
5675                 trans = btrfs_join_transaction(tree_root);
5676         else
5677                 trans = btrfs_start_transaction(tree_root, 0);
5678         if (IS_ERR(trans)) {
5679                 err = PTR_ERR(trans);
5680                 goto out_free;
5681         }
5682
5683         err = btrfs_run_delayed_items(trans);
5684         if (err)
5685                 goto out_end_trans;
5686
5687         /*
5688          * This will help us catch people modifying the fs tree while we're
5689          * dropping it.  It is unsafe to mess with the fs tree while it's being
5690          * dropped as we unlock the root node and parent nodes as we walk down
5691          * the tree, assuming nothing will change.  If something does change
5692          * then we'll have stale information and drop references to blocks we've
5693          * already dropped.
5694          */
5695         set_bit(BTRFS_ROOT_DELETING, &root->state);
5696         unfinished_drop = test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state);
5697
5698         if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
5699                 level = btrfs_header_level(root->node);
5700                 path->nodes[level] = btrfs_lock_root_node(root);
5701                 path->slots[level] = 0;
5702                 path->locks[level] = BTRFS_WRITE_LOCK;
5703                 memset(&wc->update_progress, 0,
5704                        sizeof(wc->update_progress));
5705         } else {
5706                 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
5707                 memcpy(&wc->update_progress, &key,
5708                        sizeof(wc->update_progress));
5709
5710                 level = btrfs_root_drop_level(root_item);
5711                 BUG_ON(level == 0);
5712                 path->lowest_level = level;
5713                 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
5714                 path->lowest_level = 0;
5715                 if (ret < 0) {
5716                         err = ret;
5717                         goto out_end_trans;
5718                 }
5719                 WARN_ON(ret > 0);
5720
5721                 /*
5722                  * unlock our path, this is safe because only this
5723                  * function is allowed to delete this snapshot
5724                  */
5725                 btrfs_unlock_up_safe(path, 0);
5726
5727                 level = btrfs_header_level(root->node);
5728                 while (1) {
5729                         btrfs_tree_lock(path->nodes[level]);
5730                         path->locks[level] = BTRFS_WRITE_LOCK;
5731
5732                         ret = btrfs_lookup_extent_info(trans, fs_info,
5733                                                 path->nodes[level]->start,
5734                                                 level, 1, &wc->refs[level],
5735                                                 &wc->flags[level]);
5736                         if (ret < 0) {
5737                                 err = ret;
5738                                 goto out_end_trans;
5739                         }
5740                         BUG_ON(wc->refs[level] == 0);
5741
5742                         if (level == btrfs_root_drop_level(root_item))
5743                                 break;
5744
5745                         btrfs_tree_unlock(path->nodes[level]);
5746                         path->locks[level] = 0;
5747                         WARN_ON(wc->refs[level] != 1);
5748                         level--;
5749                 }
5750         }
5751
5752         wc->restarted = test_bit(BTRFS_ROOT_DEAD_TREE, &root->state);
5753         wc->level = level;
5754         wc->shared_level = -1;
5755         wc->stage = DROP_REFERENCE;
5756         wc->update_ref = update_ref;
5757         wc->keep_locks = 0;
5758         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
5759
5760         while (1) {
5761
5762                 ret = walk_down_tree(trans, root, path, wc);
5763                 if (ret < 0) {
5764                         err = ret;
5765                         break;
5766                 }
5767
5768                 ret = walk_up_tree(trans, root, path, wc, BTRFS_MAX_LEVEL);
5769                 if (ret < 0) {
5770                         err = ret;
5771                         break;
5772                 }
5773
5774                 if (ret > 0) {
5775                         BUG_ON(wc->stage != DROP_REFERENCE);
5776                         break;
5777                 }
5778
5779                 if (wc->stage == DROP_REFERENCE) {
5780                         wc->drop_level = wc->level;
5781                         btrfs_node_key_to_cpu(path->nodes[wc->drop_level],
5782                                               &wc->drop_progress,
5783                                               path->slots[wc->drop_level]);
5784                 }
5785                 btrfs_cpu_key_to_disk(&root_item->drop_progress,
5786                                       &wc->drop_progress);
5787                 btrfs_set_root_drop_level(root_item, wc->drop_level);
5788
5789                 BUG_ON(wc->level == 0);
5790                 if (btrfs_should_end_transaction(trans) ||
5791                     (!for_reloc && btrfs_need_cleaner_sleep(fs_info))) {
5792                         ret = btrfs_update_root(trans, tree_root,
5793                                                 &root->root_key,
5794                                                 root_item);
5795                         if (ret) {
5796                                 btrfs_abort_transaction(trans, ret);
5797                                 err = ret;
5798                                 goto out_end_trans;
5799                         }
5800
5801                         btrfs_end_transaction_throttle(trans);
5802                         if (!for_reloc && btrfs_need_cleaner_sleep(fs_info)) {
5803                                 btrfs_debug(fs_info,
5804                                             "drop snapshot early exit");
5805                                 err = -EAGAIN;
5806                                 goto out_free;
5807                         }
5808
5809                        /*
5810                         * Use join to avoid potential EINTR from transaction
5811                         * start. See wait_reserve_ticket and the whole
5812                         * reservation callchain.
5813                         */
5814                         if (for_reloc)
5815                                 trans = btrfs_join_transaction(tree_root);
5816                         else
5817                                 trans = btrfs_start_transaction(tree_root, 0);
5818                         if (IS_ERR(trans)) {
5819                                 err = PTR_ERR(trans);
5820                                 goto out_free;
5821                         }
5822                 }
5823         }
5824         btrfs_release_path(path);
5825         if (err)
5826                 goto out_end_trans;
5827
5828         ret = btrfs_del_root(trans, &root->root_key);
5829         if (ret) {
5830                 btrfs_abort_transaction(trans, ret);
5831                 err = ret;
5832                 goto out_end_trans;
5833         }
5834
5835         if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
5836                 ret = btrfs_find_root(tree_root, &root->root_key, path,
5837                                       NULL, NULL);
5838                 if (ret < 0) {
5839                         btrfs_abort_transaction(trans, ret);
5840                         err = ret;
5841                         goto out_end_trans;
5842                 } else if (ret > 0) {
5843                         /* if we fail to delete the orphan item this time
5844                          * around, it'll get picked up the next time.
5845                          *
5846                          * The most common failure here is just -ENOENT.
5847                          */
5848                         btrfs_del_orphan_item(trans, tree_root,
5849                                               root->root_key.objectid);
5850                 }
5851         }
5852
5853         /*
5854          * This subvolume is going to be completely dropped, and won't be
5855          * recorded as dirty roots, thus pertrans meta rsv will not be freed at
5856          * commit transaction time.  So free it here manually.
5857          */
5858         btrfs_qgroup_convert_reserved_meta(root, INT_MAX);
5859         btrfs_qgroup_free_meta_all_pertrans(root);
5860
5861         if (test_bit(BTRFS_ROOT_IN_RADIX, &root->state))
5862                 btrfs_add_dropped_root(trans, root);
5863         else
5864                 btrfs_put_root(root);
5865         root_dropped = true;
5866 out_end_trans:
5867         btrfs_end_transaction_throttle(trans);
5868 out_free:
5869         kfree(wc);
5870         btrfs_free_path(path);
5871 out:
5872         /*
5873          * We were an unfinished drop root, check to see if there are any
5874          * pending, and if not clear and wake up any waiters.
5875          */
5876         if (!err && unfinished_drop)
5877                 btrfs_maybe_wake_unfinished_drop(fs_info);
5878
5879         /*
5880          * So if we need to stop dropping the snapshot for whatever reason we
5881          * need to make sure to add it back to the dead root list so that we
5882          * keep trying to do the work later.  This also cleans up roots if we
5883          * don't have it in the radix (like when we recover after a power fail
5884          * or unmount) so we don't leak memory.
5885          */
5886         if (!for_reloc && !root_dropped)
5887                 btrfs_add_dead_root(root);
5888         return err;
5889 }
5890
5891 /*
5892  * drop subtree rooted at tree block 'node'.
5893  *
5894  * NOTE: this function will unlock and release tree block 'node'
5895  * only used by relocation code
5896  */
5897 int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
5898                         struct btrfs_root *root,
5899                         struct extent_buffer *node,
5900                         struct extent_buffer *parent)
5901 {
5902         struct btrfs_fs_info *fs_info = root->fs_info;
5903         struct btrfs_path *path;
5904         struct walk_control *wc;
5905         int level;
5906         int parent_level;
5907         int ret = 0;
5908         int wret;
5909
5910         BUG_ON(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
5911
5912         path = btrfs_alloc_path();
5913         if (!path)
5914                 return -ENOMEM;
5915
5916         wc = kzalloc(sizeof(*wc), GFP_NOFS);
5917         if (!wc) {
5918                 btrfs_free_path(path);
5919                 return -ENOMEM;
5920         }
5921
5922         btrfs_assert_tree_write_locked(parent);
5923         parent_level = btrfs_header_level(parent);
5924         atomic_inc(&parent->refs);
5925         path->nodes[parent_level] = parent;
5926         path->slots[parent_level] = btrfs_header_nritems(parent);
5927
5928         btrfs_assert_tree_write_locked(node);
5929         level = btrfs_header_level(node);
5930         path->nodes[level] = node;
5931         path->slots[level] = 0;
5932         path->locks[level] = BTRFS_WRITE_LOCK;
5933
5934         wc->refs[parent_level] = 1;
5935         wc->flags[parent_level] = BTRFS_BLOCK_FLAG_FULL_BACKREF;
5936         wc->level = level;
5937         wc->shared_level = -1;
5938         wc->stage = DROP_REFERENCE;
5939         wc->update_ref = 0;
5940         wc->keep_locks = 1;
5941         wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
5942
5943         while (1) {
5944                 wret = walk_down_tree(trans, root, path, wc);
5945                 if (wret < 0) {
5946                         ret = wret;
5947                         break;
5948                 }
5949
5950                 wret = walk_up_tree(trans, root, path, wc, parent_level);
5951                 if (wret < 0)
5952                         ret = wret;
5953                 if (wret != 0)
5954                         break;
5955         }
5956
5957         kfree(wc);
5958         btrfs_free_path(path);
5959         return ret;
5960 }
5961
5962 /*
5963  * helper to account the unused space of all the readonly block group in the
5964  * space_info. takes mirrors into account.
5965  */
5966 u64 btrfs_account_ro_block_groups_free_space(struct btrfs_space_info *sinfo)
5967 {
5968         struct btrfs_block_group *block_group;
5969         u64 free_bytes = 0;
5970         int factor;
5971
5972         /* It's df, we don't care if it's racy */
5973         if (list_empty(&sinfo->ro_bgs))
5974                 return 0;
5975
5976         spin_lock(&sinfo->lock);
5977         list_for_each_entry(block_group, &sinfo->ro_bgs, ro_list) {
5978                 spin_lock(&block_group->lock);
5979
5980                 if (!block_group->ro) {
5981                         spin_unlock(&block_group->lock);
5982                         continue;
5983                 }
5984
5985                 factor = btrfs_bg_type_to_factor(block_group->flags);
5986                 free_bytes += (block_group->length -
5987                                block_group->used) * factor;
5988
5989                 spin_unlock(&block_group->lock);
5990         }
5991         spin_unlock(&sinfo->lock);
5992
5993         return free_bytes;
5994 }
5995
5996 int btrfs_error_unpin_extent_range(struct btrfs_fs_info *fs_info,
5997                                    u64 start, u64 end)
5998 {
5999         return unpin_extent_range(fs_info, start, end, false);
6000 }
6001
6002 /*
6003  * It used to be that old block groups would be left around forever.
6004  * Iterating over them would be enough to trim unused space.  Since we
6005  * now automatically remove them, we also need to iterate over unallocated
6006  * space.
6007  *
6008  * We don't want a transaction for this since the discard may take a
6009  * substantial amount of time.  We don't require that a transaction be
6010  * running, but we do need to take a running transaction into account
6011  * to ensure that we're not discarding chunks that were released or
6012  * allocated in the current transaction.
6013  *
6014  * Holding the chunks lock will prevent other threads from allocating
6015  * or releasing chunks, but it won't prevent a running transaction
6016  * from committing and releasing the memory that the pending chunks
6017  * list head uses.  For that, we need to take a reference to the
6018  * transaction and hold the commit root sem.  We only need to hold
6019  * it while performing the free space search since we have already
6020  * held back allocations.
6021  */
6022 static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)
6023 {
6024         u64 start = BTRFS_DEVICE_RANGE_RESERVED, len = 0, end = 0;
6025         int ret;
6026
6027         *trimmed = 0;
6028
6029         /* Discard not supported = nothing to do. */
6030         if (!bdev_max_discard_sectors(device->bdev))
6031                 return 0;
6032
6033         /* Not writable = nothing to do. */
6034         if (!test_bit(BTRFS_DEV_STATE_WRITEABLE, &device->dev_state))
6035                 return 0;
6036
6037         /* No free space = nothing to do. */
6038         if (device->total_bytes <= device->bytes_used)
6039                 return 0;
6040
6041         ret = 0;
6042
6043         while (1) {
6044                 struct btrfs_fs_info *fs_info = device->fs_info;
6045                 u64 bytes;
6046
6047                 ret = mutex_lock_interruptible(&fs_info->chunk_mutex);
6048                 if (ret)
6049                         break;
6050
6051                 find_first_clear_extent_bit(&device->alloc_state, start,
6052                                             &start, &end,
6053                                             CHUNK_TRIMMED | CHUNK_ALLOCATED);
6054
6055                 /* Check if there are any CHUNK_* bits left */
6056                 if (start > device->total_bytes) {
6057                         WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
6058                         btrfs_warn_in_rcu(fs_info,
6059 "ignoring attempt to trim beyond device size: offset %llu length %llu device %s device size %llu",
6060                                           start, end - start + 1,
6061                                           rcu_str_deref(device->name),
6062                                           device->total_bytes);
6063                         mutex_unlock(&fs_info->chunk_mutex);
6064                         ret = 0;
6065                         break;
6066                 }
6067
6068                 /* Ensure we skip the reserved space on each device. */
6069                 start = max_t(u64, start, BTRFS_DEVICE_RANGE_RESERVED);
6070
6071                 /*
6072                  * If find_first_clear_extent_bit find a range that spans the
6073                  * end of the device it will set end to -1, in this case it's up
6074                  * to the caller to trim the value to the size of the device.
6075                  */
6076                 end = min(end, device->total_bytes - 1);
6077
6078                 len = end - start + 1;
6079
6080                 /* We didn't find any extents */
6081                 if (!len) {
6082                         mutex_unlock(&fs_info->chunk_mutex);
6083                         ret = 0;
6084                         break;
6085                 }
6086
6087                 ret = btrfs_issue_discard(device->bdev, start, len,
6088                                           &bytes);
6089                 if (!ret)
6090                         set_extent_bits(&device->alloc_state, start,
6091                                         start + bytes - 1,
6092                                         CHUNK_TRIMMED);
6093                 mutex_unlock(&fs_info->chunk_mutex);
6094
6095                 if (ret)
6096                         break;
6097
6098                 start += len;
6099                 *trimmed += bytes;
6100
6101                 if (fatal_signal_pending(current)) {
6102                         ret = -ERESTARTSYS;
6103                         break;
6104                 }
6105
6106                 cond_resched();
6107         }
6108
6109         return ret;
6110 }
6111
6112 /*
6113  * Trim the whole filesystem by:
6114  * 1) trimming the free space in each block group
6115  * 2) trimming the unallocated space on each device
6116  *
6117  * This will also continue trimming even if a block group or device encounters
6118  * an error.  The return value will be the last error, or 0 if nothing bad
6119  * happens.
6120  */
6121 int btrfs_trim_fs(struct btrfs_fs_info *fs_info, struct fstrim_range *range)
6122 {
6123         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
6124         struct btrfs_block_group *cache = NULL;
6125         struct btrfs_device *device;
6126         u64 group_trimmed;
6127         u64 range_end = U64_MAX;
6128         u64 start;
6129         u64 end;
6130         u64 trimmed = 0;
6131         u64 bg_failed = 0;
6132         u64 dev_failed = 0;
6133         int bg_ret = 0;
6134         int dev_ret = 0;
6135         int ret = 0;
6136
6137         if (range->start == U64_MAX)
6138                 return -EINVAL;
6139
6140         /*
6141          * Check range overflow if range->len is set.
6142          * The default range->len is U64_MAX.
6143          */
6144         if (range->len != U64_MAX &&
6145             check_add_overflow(range->start, range->len, &range_end))
6146                 return -EINVAL;
6147
6148         cache = btrfs_lookup_first_block_group(fs_info, range->start);
6149         for (; cache; cache = btrfs_next_block_group(cache)) {
6150                 if (cache->start >= range_end) {
6151                         btrfs_put_block_group(cache);
6152                         break;
6153                 }
6154
6155                 start = max(range->start, cache->start);
6156                 end = min(range_end, cache->start + cache->length);
6157
6158                 if (end - start >= range->minlen) {
6159                         if (!btrfs_block_group_done(cache)) {
6160                                 ret = btrfs_cache_block_group(cache, true);
6161                                 if (ret) {
6162                                         bg_failed++;
6163                                         bg_ret = ret;
6164                                         continue;
6165                                 }
6166                         }
6167                         ret = btrfs_trim_block_group(cache,
6168                                                      &group_trimmed,
6169                                                      start,
6170                                                      end,
6171                                                      range->minlen);
6172
6173                         trimmed += group_trimmed;
6174                         if (ret) {
6175                                 bg_failed++;
6176                                 bg_ret = ret;
6177                                 continue;
6178                         }
6179                 }
6180         }
6181
6182         if (bg_failed)
6183                 btrfs_warn(fs_info,
6184                         "failed to trim %llu block group(s), last error %d",
6185                         bg_failed, bg_ret);
6186
6187         mutex_lock(&fs_devices->device_list_mutex);
6188         list_for_each_entry(device, &fs_devices->devices, dev_list) {
6189                 if (test_bit(BTRFS_DEV_STATE_MISSING, &device->dev_state))
6190                         continue;
6191
6192                 ret = btrfs_trim_free_extents(device, &group_trimmed);
6193                 if (ret) {
6194                         dev_failed++;
6195                         dev_ret = ret;
6196                         break;
6197                 }
6198
6199                 trimmed += group_trimmed;
6200         }
6201         mutex_unlock(&fs_devices->device_list_mutex);
6202
6203         if (dev_failed)
6204                 btrfs_warn(fs_info,
6205                         "failed to trim %llu device(s), last error %d",
6206                         dev_failed, dev_ret);
6207         range->len = trimmed;
6208         if (bg_ret)
6209                 return bg_ret;
6210         return dev_ret;
6211 }