fs/btrfs/ordered-data.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/slab.h>
  20 #include <linux/blkdev.h>
  21 #include <linux/writeback.h>
  22 #include <linux/pagevec.h>
  23 #include "ctree.h"
  24 #include "transaction.h"
  25 #include "btrfs_inode.h"
  26 #include "extent_io.h"
  27 #include "disk-io.h"
  28 #include "compression.h"
  29
  30 static struct kmem_cache *btrfs_ordered_extent_cache;
  31
  32 static u64 entry_end(struct btrfs_ordered_extent *entry)
  33 {
  34         if (entry->file_offset + entry->len < entry->file_offset)
  35                 return (u64)-1;
  36         return entry->file_offset + entry->len;
  37 }
  38
  39 /* returns NULL if the insertion worked, or it returns the node it did find
  40  * in the tree
  41  */
  42 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  43                                    struct rb_node *node)
  44 {
  45         struct rb_node **p = &root->rb_node;
  46         struct rb_node *parent = NULL;
  47         struct btrfs_ordered_extent *entry;
  48
  49         while (*p) {
  50                 parent = *p;
  51                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  52
  53                 if (file_offset < entry->file_offset)
  54                         p = &(*p)->rb_left;
  55                 else if (file_offset >= entry_end(entry))
  56                         p = &(*p)->rb_right;
  57                 else
  58                         return parent;
  59         }
  60
  61         rb_link_node(node, parent, p);
  62         rb_insert_color(node, root);
  63         return NULL;
  64 }
  65
  66 static void ordered_data_tree_panic(struct inode *inode, int errno,
  67                                                u64 offset)
  68 {
  69         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
  70         btrfs_panic(fs_info, errno,
  71                     "Inconsistency in ordered tree at offset %llu", offset);
  72 }
  73
  74 /*
  75  * look for a given offset in the tree, and if it can't be found return the
  76  * first lesser offset
  77  */
  78 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  79                                      struct rb_node **prev_ret)
  80 {
  81         struct rb_node *n = root->rb_node;
  82         struct rb_node *prev = NULL;
  83         struct rb_node *test;
  84         struct btrfs_ordered_extent *entry;
  85         struct btrfs_ordered_extent *prev_entry = NULL;
  86
  87         while (n) {
  88                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  89                 prev = n;
  90                 prev_entry = entry;
  91
  92                 if (file_offset < entry->file_offset)
  93                         n = n->rb_left;
  94                 else if (file_offset >= entry_end(entry))
  95                         n = n->rb_right;
  96                 else
  97                         return n;
  98         }
  99         if (!prev_ret)
 100                 return NULL;
 101
 102         while (prev && file_offset >= entry_end(prev_entry)) {
 103                 test = rb_next(prev);
 104                 if (!test)
 105                         break;
 106                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 107                                       rb_node);
 108                 if (file_offset < entry_end(prev_entry))
 109                         break;
 110
 111                 prev = test;
 112         }
 113         if (prev)
 114                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
 115                                       rb_node);
 116         while (prev && file_offset < entry_end(prev_entry)) {
 117                 test = rb_prev(prev);
 118                 if (!test)
 119                         break;
 120                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 121                                       rb_node);
 122                 prev = test;
 123         }
 124         *prev_ret = prev;
 125         return NULL;
 126 }
 127
 128 /*
 129  * helper to check if a given offset is inside a given entry
 130  */
 131 static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
 132 {
 133         if (file_offset < entry->file_offset ||
 134             entry->file_offset + entry->len <= file_offset)
 135                 return 0;
 136         return 1;
 137 }
 138
 139 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 140                           u64 len)
 141 {
 142         if (file_offset + len <= entry->file_offset ||
 143             entry->file_offset + entry->len <= file_offset)
 144                 return 0;
 145         return 1;
 146 }
 147
 148 /*
 149  * look find the first ordered struct that has this offset, otherwise
 150  * the first one less than this offset
 151  */
 152 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 153                                           u64 file_offset)
 154 {
 155         struct rb_root *root = &tree->tree;
 156         struct rb_node *prev = NULL;
 157         struct rb_node *ret;
 158         struct btrfs_ordered_extent *entry;
 159
 160         if (tree->last) {
 161                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 162                                  rb_node);
 163                 if (offset_in_entry(entry, file_offset))
 164                         return tree->last;
 165         }
 166         ret = __tree_search(root, file_offset, &prev);
 167         if (!ret)
 168                 ret = prev;
 169         if (ret)
 170                 tree->last = ret;
 171         return ret;
 172 }
 173
 174 /* allocate and add a new ordered_extent into the per-inode tree.
 175  * file_offset is the logical offset in the file
 176  *
 177  * start is the disk block number of an extent already reserved in the
 178  * extent allocation tree
 179  *
 180  * len is the length of the extent
 181  *
 182  * The tree is given a single reference on the ordered extent that was
 183  * inserted.
 184  */
 185 static int __btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 186                                       u64 start, u64 len, u64 disk_len,
 187                                       int type, int dio, int compress_type)
 188 {
 189         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 190         struct btrfs_root *root = BTRFS_I(inode)->root;
 191         struct btrfs_ordered_inode_tree *tree;
 192         struct rb_node *node;
 193         struct btrfs_ordered_extent *entry;
 194
 195         tree = &BTRFS_I(inode)->ordered_tree;
 196         entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 197         if (!entry)
 198                 return -ENOMEM;
 199
 200         entry->file_offset = file_offset;
 201         entry->start = start;
 202         entry->len = len;
 203         entry->disk_len = disk_len;
 204         entry->bytes_left = len;
 205         entry->inode = igrab(inode);
 206         entry->compress_type = compress_type;
 207         entry->truncated_len = (u64)-1;
 208         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 209                 set_bit(type, &entry->flags);
 210
 211         if (dio)
 212                 set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
 213
 214         /* one ref for the tree */
 215         refcount_set(&entry->refs, 1);
 216         init_waitqueue_head(&entry->wait);
 217         INIT_LIST_HEAD(&entry->list);
 218         INIT_LIST_HEAD(&entry->root_extent_list);
 219         INIT_LIST_HEAD(&entry->work_list);
 220         init_completion(&entry->completion);
 221         INIT_LIST_HEAD(&entry->log_list);
 222         INIT_LIST_HEAD(&entry->trans_list);
 223
 224         trace_btrfs_ordered_extent_add(inode, entry);
 225
 226         spin_lock_irq(&tree->lock);
 227         node = tree_insert(&tree->tree, file_offset,
 228                            &entry->rb_node);
 229         if (node)
 230                 ordered_data_tree_panic(inode, -EEXIST, file_offset);
 231         spin_unlock_irq(&tree->lock);
 232
 233         spin_lock(&root->ordered_extent_lock);
 234         list_add_tail(&entry->root_extent_list,
 235                       &root->ordered_extents);
 236         root->nr_ordered_extents++;
 237         if (root->nr_ordered_extents == 1) {
 238                 spin_lock(&fs_info->ordered_root_lock);
 239                 BUG_ON(!list_empty(&root->ordered_root));
 240                 list_add_tail(&root->ordered_root, &fs_info->ordered_roots);
 241                 spin_unlock(&fs_info->ordered_root_lock);
 242         }
 243         spin_unlock(&root->ordered_extent_lock);
 244
 245         return 0;
 246 }
 247
 248 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 249                              u64 start, u64 len, u64 disk_len, int type)
 250 {
 251         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 252                                           disk_len, type, 0,
 253                                           BTRFS_COMPRESS_NONE);
 254 }
 255
 256 int btrfs_add_ordered_extent_dio(struct inode *inode, u64 file_offset,
 257                                  u64 start, u64 len, u64 disk_len, int type)
 258 {
 259         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 260                                           disk_len, type, 1,
 261                                           BTRFS_COMPRESS_NONE);
 262 }
 263
 264 int btrfs_add_ordered_extent_compress(struct inode *inode, u64 file_offset,
 265                                       u64 start, u64 len, u64 disk_len,
 266                                       int type, int compress_type)
 267 {
 268         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 269                                           disk_len, type, 0,
 270                                           compress_type);
 271 }
 272
 273 /*
 274  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 275  * when an ordered extent is finished.  If the list covers more than one
 276  * ordered extent, it is split across multiples.
 277  */
 278 void btrfs_add_ordered_sum(struct inode *inode,
 279                            struct btrfs_ordered_extent *entry,
 280                            struct btrfs_ordered_sum *sum)
 281 {
 282         struct btrfs_ordered_inode_tree *tree;
 283
 284         tree = &BTRFS_I(inode)->ordered_tree;
 285         spin_lock_irq(&tree->lock);
 286         list_add_tail(&sum->list, &entry->list);
 287         spin_unlock_irq(&tree->lock);
 288 }
 289
 290 /*
 291  * this is used to account for finished IO across a given range
 292  * of the file.  The IO may span ordered extents.  If
 293  * a given ordered_extent is completely done, 1 is returned, otherwise
 294  * 0.
 295  *
 296  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 297  * to make sure this function only returns 1 once for a given ordered extent.
 298  *
 299  * file_offset is updated to one byte past the range that is recorded as
 300  * complete.  This allows you to walk forward in the file.
 301  */
 302 int btrfs_dec_test_first_ordered_pending(struct inode *inode,
 303                                    struct btrfs_ordered_extent **cached,
 304                                    u64 *file_offset, u64 io_size, int uptodate)
 305 {
 306         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 307         struct btrfs_ordered_inode_tree *tree;
 308         struct rb_node *node;
 309         struct btrfs_ordered_extent *entry = NULL;
 310         int ret;
 311         unsigned long flags;
 312         u64 dec_end;
 313         u64 dec_start;
 314         u64 to_dec;
 315
 316         tree = &BTRFS_I(inode)->ordered_tree;
 317         spin_lock_irqsave(&tree->lock, flags);
 318         node = tree_search(tree, *file_offset);
 319         if (!node) {
 320                 ret = 1;
 321                 goto out;
 322         }
 323
 324         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 325         if (!offset_in_entry(entry, *file_offset)) {
 326                 ret = 1;
 327                 goto out;
 328         }
 329
 330         dec_start = max(*file_offset, entry->file_offset);
 331         dec_end = min(*file_offset + io_size, entry->file_offset +
 332                       entry->len);
 333         *file_offset = dec_end;
 334         if (dec_start > dec_end) {
 335                 btrfs_crit(fs_info, "bad ordering dec_start %llu end %llu",
 336                            dec_start, dec_end);
 337         }
 338         to_dec = dec_end - dec_start;
 339         if (to_dec > entry->bytes_left) {
 340                 btrfs_crit(fs_info,
 341                            "bad ordered accounting left %llu size %llu",
 342                            entry->bytes_left, to_dec);
 343         }
 344         entry->bytes_left -= to_dec;
 345         if (!uptodate)
 346                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 347
 348         if (entry->bytes_left == 0) {
 349                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 350                 /*
 351                  * Implicit memory barrier after test_and_set_bit
 352                  */
 353                 if (waitqueue_active(&entry->wait))
 354                         wake_up(&entry->wait);
 355         } else {
 356                 ret = 1;
 357         }
 358 out:
 359         if (!ret && cached && entry) {
 360                 *cached = entry;
 361                 refcount_inc(&entry->refs);
 362         }
 363         spin_unlock_irqrestore(&tree->lock, flags);
 364         return ret == 0;
 365 }
 366
 367 /*
 368  * this is used to account for finished IO across a given range
 369  * of the file.  The IO should not span ordered extents.  If
 370  * a given ordered_extent is completely done, 1 is returned, otherwise
 371  * 0.
 372  *
 373  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 374  * to make sure this function only returns 1 once for a given ordered extent.
 375  */
 376 int btrfs_dec_test_ordered_pending(struct inode *inode,
 377                                    struct btrfs_ordered_extent **cached,
 378                                    u64 file_offset, u64 io_size, int uptodate)
 379 {
 380         struct btrfs_ordered_inode_tree *tree;
 381         struct rb_node *node;
 382         struct btrfs_ordered_extent *entry = NULL;
 383         unsigned long flags;
 384         int ret;
 385
 386         tree = &BTRFS_I(inode)->ordered_tree;
 387         spin_lock_irqsave(&tree->lock, flags);
 388         if (cached && *cached) {
 389                 entry = *cached;
 390                 goto have_entry;
 391         }
 392
 393         node = tree_search(tree, file_offset);
 394         if (!node) {
 395                 ret = 1;
 396                 goto out;
 397         }
 398
 399         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 400 have_entry:
 401         if (!offset_in_entry(entry, file_offset)) {
 402                 ret = 1;
 403                 goto out;
 404         }
 405
 406         if (io_size > entry->bytes_left) {
 407                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
 408                            "bad ordered accounting left %llu size %llu",
 409                        entry->bytes_left, io_size);
 410         }
 411         entry->bytes_left -= io_size;
 412         if (!uptodate)
 413                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 414
 415         if (entry->bytes_left == 0) {
 416                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 417                 /*
 418                  * Implicit memory barrier after test_and_set_bit
 419                  */
 420                 if (waitqueue_active(&entry->wait))
 421                         wake_up(&entry->wait);
 422         } else {
 423                 ret = 1;
 424         }
 425 out:
 426         if (!ret && cached && entry) {
 427                 *cached = entry;
 428                 refcount_inc(&entry->refs);
 429         }
 430         spin_unlock_irqrestore(&tree->lock, flags);
 431         return ret == 0;
 432 }
 433
 434 /* Needs to either be called under a log transaction or the log_mutex */
 435 void btrfs_get_logged_extents(struct btrfs_inode *inode,
 436                               struct list_head *logged_list,
 437                               const loff_t start,
 438                               const loff_t end)
 439 {
 440         struct btrfs_ordered_inode_tree *tree;
 441         struct btrfs_ordered_extent *ordered;
 442         struct rb_node *n;
 443         struct rb_node *prev;
 444
 445         tree = &inode->ordered_tree;
 446         spin_lock_irq(&tree->lock);
 447         n = __tree_search(&tree->tree, end, &prev);
 448         if (!n)
 449                 n = prev;
 450         for (; n; n = rb_prev(n)) {
 451                 ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
 452                 if (ordered->file_offset > end)
 453                         continue;
 454                 if (entry_end(ordered) <= start)
 455                         break;
 456                 if (test_and_set_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
 457                         continue;
 458                 list_add(&ordered->log_list, logged_list);
 459                 refcount_inc(&ordered->refs);
 460         }
 461         spin_unlock_irq(&tree->lock);
 462 }
 463
 464 void btrfs_put_logged_extents(struct list_head *logged_list)
 465 {
 466         struct btrfs_ordered_extent *ordered;
 467
 468         while (!list_empty(logged_list)) {
 469                 ordered = list_first_entry(logged_list,
 470                                            struct btrfs_ordered_extent,
 471                                            log_list);
 472                 list_del_init(&ordered->log_list);
 473                 btrfs_put_ordered_extent(ordered);
 474         }
 475 }
 476
 477 void btrfs_submit_logged_extents(struct list_head *logged_list,
 478                                  struct btrfs_root *log)
 479 {
 480         int index = log->log_transid % 2;
 481
 482         spin_lock_irq(&log->log_extents_lock[index]);
 483         list_splice_tail(logged_list, &log->logged_list[index]);
 484         spin_unlock_irq(&log->log_extents_lock[index]);
 485 }
 486
 487 void btrfs_wait_logged_extents(struct btrfs_trans_handle *trans,
 488                                struct btrfs_root *log, u64 transid)
 489 {
 490         struct btrfs_ordered_extent *ordered;
 491         int index = transid % 2;
 492
 493         spin_lock_irq(&log->log_extents_lock[index]);
 494         while (!list_empty(&log->logged_list[index])) {
 495                 struct inode *inode;
 496                 ordered = list_first_entry(&log->logged_list[index],
 497                                            struct btrfs_ordered_extent,
 498                                            log_list);
 499                 list_del_init(&ordered->log_list);
 500                 inode = ordered->inode;
 501                 spin_unlock_irq(&log->log_extents_lock[index]);
 502
 503                 if (!test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags) &&
 504                     !test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags)) {
 505                         u64 start = ordered->file_offset;
 506                         u64 end = ordered->file_offset + ordered->len - 1;
 507
 508                         WARN_ON(!inode);
 509                         filemap_fdatawrite_range(inode->i_mapping, start, end);
 510                 }
 511                 wait_event(ordered->wait, test_bit(BTRFS_ORDERED_IO_DONE,
 512                                                    &ordered->flags));
 513
 514                 /*
 515                  * In order to keep us from losing our ordered extent
 516                  * information when committing the transaction we have to make
 517                  * sure that any logged extents are completed when we go to
 518                  * commit the transaction.  To do this we simply increase the
 519                  * current transactions pending_ordered counter and decrement it
 520                  * when the ordered extent completes.
 521                  */
 522                 if (!test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) {
 523                         struct btrfs_ordered_inode_tree *tree;
 524
 525                         tree = &BTRFS_I(inode)->ordered_tree;
 526                         spin_lock_irq(&tree->lock);
 527                         if (!test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) {
 528                                 set_bit(BTRFS_ORDERED_PENDING, &ordered->flags);
 529                                 atomic_inc(&trans->transaction->pending_ordered);
 530                         }
 531                         spin_unlock_irq(&tree->lock);
 532                 }
 533                 btrfs_put_ordered_extent(ordered);
 534                 spin_lock_irq(&log->log_extents_lock[index]);
 535         }
 536         spin_unlock_irq(&log->log_extents_lock[index]);
 537 }
 538
 539 void btrfs_free_logged_extents(struct btrfs_root *log, u64 transid)
 540 {
 541         struct btrfs_ordered_extent *ordered;
 542         int index = transid % 2;
 543
 544         spin_lock_irq(&log->log_extents_lock[index]);
 545         while (!list_empty(&log->logged_list[index])) {
 546                 ordered = list_first_entry(&log->logged_list[index],
 547                                            struct btrfs_ordered_extent,
 548                                            log_list);
 549                 list_del_init(&ordered->log_list);
 550                 spin_unlock_irq(&log->log_extents_lock[index]);
 551                 btrfs_put_ordered_extent(ordered);
 552                 spin_lock_irq(&log->log_extents_lock[index]);
 553         }
 554         spin_unlock_irq(&log->log_extents_lock[index]);
 555 }
 556
 557 /*
 558  * used to drop a reference on an ordered extent.  This will free
 559  * the extent if the last reference is dropped
 560  */
 561 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 562 {
 563         struct list_head *cur;
 564         struct btrfs_ordered_sum *sum;
 565
 566         trace_btrfs_ordered_extent_put(entry->inode, entry);
 567
 568         if (refcount_dec_and_test(&entry->refs)) {
 569                 ASSERT(list_empty(&entry->log_list));
 570                 ASSERT(list_empty(&entry->trans_list));
 571                 ASSERT(list_empty(&entry->root_extent_list));
 572                 ASSERT(RB_EMPTY_NODE(&entry->rb_node));
 573                 if (entry->inode)
 574                         btrfs_add_delayed_iput(entry->inode);
 575                 while (!list_empty(&entry->list)) {
 576                         cur = entry->list.next;
 577                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 578                         list_del(&sum->list);
 579                         kfree(sum);
 580                 }
 581                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
 582         }
 583 }
 584
 585 /*
 586  * remove an ordered extent from the tree.  No references are dropped
 587  * and waiters are woken up.
 588  */
 589 void btrfs_remove_ordered_extent(struct inode *inode,
 590                                  struct btrfs_ordered_extent *entry)
 591 {
 592         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 593         struct btrfs_ordered_inode_tree *tree;
 594         struct btrfs_root *root = BTRFS_I(inode)->root;
 595         struct rb_node *node;
 596         bool dec_pending_ordered = false;
 597
 598         tree = &BTRFS_I(inode)->ordered_tree;
 599         spin_lock_irq(&tree->lock);
 600         node = &entry->rb_node;
 601         rb_erase(node, &tree->tree);
 602         RB_CLEAR_NODE(node);
 603         if (tree->last == node)
 604                 tree->last = NULL;
 605         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 606         if (test_and_clear_bit(BTRFS_ORDERED_PENDING, &entry->flags))
 607                 dec_pending_ordered = true;
 608         spin_unlock_irq(&tree->lock);
 609
 610         /*
 611          * The current running transaction is waiting on us, we need to let it
 612          * know that we're complete and wake it up.
 613          */
 614         if (dec_pending_ordered) {
 615                 struct btrfs_transaction *trans;
 616
 617                 /*
 618                  * The checks for trans are just a formality, it should be set,
 619                  * but if it isn't we don't want to deref/assert under the spin
 620                  * lock, so be nice and check if trans is set, but ASSERT() so
 621                  * if it isn't set a developer will notice.
 622                  */
 623                 spin_lock(&fs_info->trans_lock);
 624                 trans = fs_info->running_transaction;
 625                 if (trans)
 626                         refcount_inc(&trans->use_count);
 627                 spin_unlock(&fs_info->trans_lock);
 628
 629                 ASSERT(trans);
 630                 if (trans) {
 631                         if (atomic_dec_and_test(&trans->pending_ordered))
 632                                 wake_up(&trans->pending_wait);
 633                         btrfs_put_transaction(trans);
 634                 }
 635         }
 636
 637         spin_lock(&root->ordered_extent_lock);
 638         list_del_init(&entry->root_extent_list);
 639         root->nr_ordered_extents--;
 640
 641         trace_btrfs_ordered_extent_remove(inode, entry);
 642
 643         if (!root->nr_ordered_extents) {
 644                 spin_lock(&fs_info->ordered_root_lock);
 645                 BUG_ON(list_empty(&root->ordered_root));
 646                 list_del_init(&root->ordered_root);
 647                 spin_unlock(&fs_info->ordered_root_lock);
 648         }
 649         spin_unlock(&root->ordered_extent_lock);
 650         wake_up(&entry->wait);
 651 }
 652
 653 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 654 {
 655         struct btrfs_ordered_extent *ordered;
 656
 657         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 658         btrfs_start_ordered_extent(ordered->inode, ordered, 1);
 659         complete(&ordered->completion);
 660 }
 661
 662 /*
 663  * wait for all the ordered extents in a root.  This is done when balancing
 664  * space between drives.
 665  */
 666 u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
 667                                const u64 range_start, const u64 range_len)
 668 {
 669         struct btrfs_fs_info *fs_info = root->fs_info;
 670         LIST_HEAD(splice);
 671         LIST_HEAD(skipped);
 672         LIST_HEAD(works);
 673         struct btrfs_ordered_extent *ordered, *next;
 674         u64 count = 0;
 675         const u64 range_end = range_start + range_len;
 676
 677         mutex_lock(&root->ordered_extent_mutex);
 678         spin_lock(&root->ordered_extent_lock);
 679         list_splice_init(&root->ordered_extents, &splice);
 680         while (!list_empty(&splice) && nr) {
 681                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 682                                            root_extent_list);
 683
 684                 if (range_end <= ordered->start ||
 685                     ordered->start + ordered->disk_len <= range_start) {
 686                         list_move_tail(&ordered->root_extent_list, &skipped);
 687                         cond_resched_lock(&root->ordered_extent_lock);
 688                         continue;
 689                 }
 690
 691                 list_move_tail(&ordered->root_extent_list,
 692                                &root->ordered_extents);
 693                 refcount_inc(&ordered->refs);
 694                 spin_unlock(&root->ordered_extent_lock);
 695
 696                 btrfs_init_work(&ordered->flush_work,
 697                                 btrfs_flush_delalloc_helper,
 698                                 btrfs_run_ordered_extent_work, NULL, NULL);
 699                 list_add_tail(&ordered->work_list, &works);
 700                 btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work);
 701
 702                 cond_resched();
 703                 spin_lock(&root->ordered_extent_lock);
 704                 if (nr != U64_MAX)
 705                         nr--;
 706                 count++;
 707         }
 708         list_splice_tail(&skipped, &root->ordered_extents);
 709         list_splice_tail(&splice, &root->ordered_extents);
 710         spin_unlock(&root->ordered_extent_lock);
 711
 712         list_for_each_entry_safe(ordered, next, &works, work_list) {
 713                 list_del_init(&ordered->work_list);
 714                 wait_for_completion(&ordered->completion);
 715                 btrfs_put_ordered_extent(ordered);
 716                 cond_resched();
 717         }
 718         mutex_unlock(&root->ordered_extent_mutex);
 719
 720         return count;
 721 }
 722
 723 u64 btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
 724                              const u64 range_start, const u64 range_len)
 725 {
 726         struct btrfs_root *root;
 727         struct list_head splice;
 728         u64 total_done = 0;
 729         u64 done;
 730
 731         INIT_LIST_HEAD(&splice);
 732
 733         mutex_lock(&fs_info->ordered_operations_mutex);
 734         spin_lock(&fs_info->ordered_root_lock);
 735         list_splice_init(&fs_info->ordered_roots, &splice);
 736         while (!list_empty(&splice) && nr) {
 737                 root = list_first_entry(&splice, struct btrfs_root,
 738                                         ordered_root);
 739                 root = btrfs_grab_fs_root(root);
 740                 BUG_ON(!root);
 741                 list_move_tail(&root->ordered_root,
 742                                &fs_info->ordered_roots);
 743                 spin_unlock(&fs_info->ordered_root_lock);
 744
 745                 done = btrfs_wait_ordered_extents(root, nr,
 746                                                   range_start, range_len);
 747                 btrfs_put_fs_root(root);
 748                 total_done += done;
 749
 750                 spin_lock(&fs_info->ordered_root_lock);
 751                 if (nr != U64_MAX) {
 752                         nr -= done;
 753                 }
 754         }
 755         list_splice_tail(&splice, &fs_info->ordered_roots);
 756         spin_unlock(&fs_info->ordered_root_lock);
 757         mutex_unlock(&fs_info->ordered_operations_mutex);
 758
 759         return total_done;
 760 }
 761
 762 /*
 763  * Used to start IO or wait for a given ordered extent to finish.
 764  *
 765  * If wait is one, this effectively waits on page writeback for all the pages
 766  * in the extent, and it waits on the io completion code to insert
 767  * metadata into the btree corresponding to the extent
 768  */
 769 void btrfs_start_ordered_extent(struct inode *inode,
 770                                        struct btrfs_ordered_extent *entry,
 771                                        int wait)
 772 {
 773         u64 start = entry->file_offset;
 774         u64 end = start + entry->len - 1;
 775
 776         trace_btrfs_ordered_extent_start(inode, entry);
 777
 778         /*
 779          * pages in the range can be dirty, clean or writeback.  We
 780          * start IO on any dirty ones so the wait doesn't stall waiting
 781          * for the flusher thread to find them
 782          */
 783         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 784                 filemap_fdatawrite_range(inode->i_mapping, start, end);
 785         if (wait) {
 786                 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 787                                                  &entry->flags));
 788         }
 789 }
 790
 791 /*
 792  * Used to wait on ordered extents across a large range of bytes.
 793  */
 794 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 795 {
 796         int ret = 0;
 797         int ret_wb = 0;
 798         u64 end;
 799         u64 orig_end;
 800         struct btrfs_ordered_extent *ordered;
 801
 802         if (start + len < start) {
 803                 orig_end = INT_LIMIT(loff_t);
 804         } else {
 805                 orig_end = start + len - 1;
 806                 if (orig_end > INT_LIMIT(loff_t))
 807                         orig_end = INT_LIMIT(loff_t);
 808         }
 809
 810         /* start IO across the range first to instantiate any delalloc
 811          * extents
 812          */
 813         ret = btrfs_fdatawrite_range(inode, start, orig_end);
 814         if (ret)
 815                 return ret;
 816
 817         /*
 818          * If we have a writeback error don't return immediately. Wait first
 819          * for any ordered extents that haven't completed yet. This is to make
 820          * sure no one can dirty the same page ranges and call writepages()
 821          * before the ordered extents complete - to avoid failures (-EEXIST)
 822          * when adding the new ordered extents to the ordered tree.
 823          */
 824         ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 825
 826         end = orig_end;
 827         while (1) {
 828                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
 829                 if (!ordered)
 830                         break;
 831                 if (ordered->file_offset > orig_end) {
 832                         btrfs_put_ordered_extent(ordered);
 833                         break;
 834                 }
 835                 if (ordered->file_offset + ordered->len <= start) {
 836                         btrfs_put_ordered_extent(ordered);
 837                         break;
 838                 }
 839                 btrfs_start_ordered_extent(inode, ordered, 1);
 840                 end = ordered->file_offset;
 841                 /*
 842                  * If the ordered extent had an error save the error but don't
 843                  * exit without waiting first for all other ordered extents in
 844                  * the range to complete.
 845                  */
 846                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 847                         ret = -EIO;
 848                 btrfs_put_ordered_extent(ordered);
 849                 if (end == 0 || end == start)
 850                         break;
 851                 end--;
 852         }
 853         return ret_wb ? ret_wb : ret;
 854 }
 855
 856 /*
 857  * find an ordered extent corresponding to file_offset.  return NULL if
 858  * nothing is found, otherwise take a reference on the extent and return it
 859  */
 860 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
 861                                                          u64 file_offset)
 862 {
 863         struct btrfs_ordered_inode_tree *tree;
 864         struct rb_node *node;
 865         struct btrfs_ordered_extent *entry = NULL;
 866
 867         tree = &BTRFS_I(inode)->ordered_tree;
 868         spin_lock_irq(&tree->lock);
 869         node = tree_search(tree, file_offset);
 870         if (!node)
 871                 goto out;
 872
 873         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 874         if (!offset_in_entry(entry, file_offset))
 875                 entry = NULL;
 876         if (entry)
 877                 refcount_inc(&entry->refs);
 878 out:
 879         spin_unlock_irq(&tree->lock);
 880         return entry;
 881 }
 882
 883 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 884  * extents that exist in the range, rather than just the start of the range.
 885  */
 886 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
 887                 struct btrfs_inode *inode, u64 file_offset, u64 len)
 888 {
 889         struct btrfs_ordered_inode_tree *tree;
 890         struct rb_node *node;
 891         struct btrfs_ordered_extent *entry = NULL;
 892
 893         tree = &inode->ordered_tree;
 894         spin_lock_irq(&tree->lock);
 895         node = tree_search(tree, file_offset);
 896         if (!node) {
 897                 node = tree_search(tree, file_offset + len);
 898                 if (!node)
 899                         goto out;
 900         }
 901
 902         while (1) {
 903                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 904                 if (range_overlaps(entry, file_offset, len))
 905                         break;
 906
 907                 if (entry->file_offset >= file_offset + len) {
 908                         entry = NULL;
 909                         break;
 910                 }
 911                 entry = NULL;
 912                 node = rb_next(node);
 913                 if (!node)
 914                         break;
 915         }
 916 out:
 917         if (entry)
 918                 refcount_inc(&entry->refs);
 919         spin_unlock_irq(&tree->lock);
 920         return entry;
 921 }
 922
 923 bool btrfs_have_ordered_extents_in_range(struct inode *inode,
 924                                          u64 file_offset,
 925                                          u64 len)
 926 {
 927         struct btrfs_ordered_extent *oe;
 928
 929         oe = btrfs_lookup_ordered_range(BTRFS_I(inode), file_offset, len);
 930         if (oe) {
 931                 btrfs_put_ordered_extent(oe);
 932                 return true;
 933         }
 934         return false;
 935 }
 936
 937 /*
 938  * lookup and return any extent before 'file_offset'.  NULL is returned
 939  * if none is found
 940  */
 941 struct btrfs_ordered_extent *
 942 btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
 943 {
 944         struct btrfs_ordered_inode_tree *tree;
 945         struct rb_node *node;
 946         struct btrfs_ordered_extent *entry = NULL;
 947
 948         tree = &BTRFS_I(inode)->ordered_tree;
 949         spin_lock_irq(&tree->lock);
 950         node = tree_search(tree, file_offset);
 951         if (!node)
 952                 goto out;
 953
 954         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 955         refcount_inc(&entry->refs);
 956 out:
 957         spin_unlock_irq(&tree->lock);
 958         return entry;
 959 }
 960
 961 /*
 962  * After an extent is done, call this to conditionally update the on disk
 963  * i_size.  i_size is updated to cover any fully written part of the file.
 964  */
 965 int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
 966                                 struct btrfs_ordered_extent *ordered)
 967 {
 968         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 969         u64 disk_i_size;
 970         u64 new_i_size;
 971         u64 i_size = i_size_read(inode);
 972         struct rb_node *node;
 973         struct rb_node *prev = NULL;
 974         struct btrfs_ordered_extent *test;
 975         int ret = 1;
 976         u64 orig_offset = offset;
 977
 978         spin_lock_irq(&tree->lock);
 979         if (ordered) {
 980                 offset = entry_end(ordered);
 981                 if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags))
 982                         offset = min(offset,
 983                                      ordered->file_offset +
 984                                      ordered->truncated_len);
 985         } else {
 986                 offset = ALIGN(offset, btrfs_inode_sectorsize(inode));
 987         }
 988         disk_i_size = BTRFS_I(inode)->disk_i_size;
 989
 990         /*
 991          * truncate file.
 992          * If ordered is not NULL, then this is called from endio and
 993          * disk_i_size will be updated by either truncate itself or any
 994          * in-flight IOs which are inside the disk_i_size.
 995          *
 996          * Because btrfs_setsize() may set i_size with disk_i_size if truncate
 997          * fails somehow, we need to make sure we have a precise disk_i_size by
 998          * updating it as usual.
 999          *
1000          */
1001         if (!ordered && disk_i_size > i_size) {
1002                 BTRFS_I(inode)->disk_i_size = orig_offset;
1003                 ret = 0;
1004                 goto out;
1005         }
1006
1007         /*
1008          * if the disk i_size is already at the inode->i_size, or
1009          * this ordered extent is inside the disk i_size, we're done
1010          */
1011         if (disk_i_size == i_size)
1012                 goto out;
1013
1014         /*
1015          * We still need to update disk_i_size if outstanding_isize is greater
1016          * than disk_i_size.
1017          */
1018         if (offset <= disk_i_size &&
1019             (!ordered || ordered->outstanding_isize <= disk_i_size))
1020                 goto out;
1021
1022         /*
1023          * walk backward from this ordered extent to disk_i_size.
1024          * if we find an ordered extent then we can't update disk i_size
1025          * yet
1026          */
1027         if (ordered) {
1028                 node = rb_prev(&ordered->rb_node);
1029         } else {
1030                 prev = tree_search(tree, offset);
1031                 /*
1032                  * we insert file extents without involving ordered struct,
1033                  * so there should be no ordered struct cover this offset
1034                  */
1035                 if (prev) {
1036                         test = rb_entry(prev, struct btrfs_ordered_extent,
1037                                         rb_node);
1038                         BUG_ON(offset_in_entry(test, offset));
1039                 }
1040                 node = prev;
1041         }
1042         for (; node; node = rb_prev(node)) {
1043                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
1044
1045                 /* We treat this entry as if it doesn't exist */
1046                 if (test_bit(BTRFS_ORDERED_UPDATED_ISIZE, &test->flags))
1047                         continue;
1048
1049                 if (entry_end(test) <= disk_i_size)
1050                         break;
1051                 if (test->file_offset >= i_size)
1052                         break;
1053
1054                 /*
1055                  * We don't update disk_i_size now, so record this undealt
1056                  * i_size. Or we will not know the real i_size.
1057                  */
1058                 if (test->outstanding_isize < offset)
1059                         test->outstanding_isize = offset;
1060                 if (ordered &&
1061                     ordered->outstanding_isize > test->outstanding_isize)
1062                         test->outstanding_isize = ordered->outstanding_isize;
1063                 goto out;
1064         }
1065         new_i_size = min_t(u64, offset, i_size);
1066
1067         /*
1068          * Some ordered extents may completed before the current one, and
1069          * we hold the real i_size in ->outstanding_isize.
1070          */
1071         if (ordered && ordered->outstanding_isize > new_i_size)
1072                 new_i_size = min_t(u64, ordered->outstanding_isize, i_size);
1073         BTRFS_I(inode)->disk_i_size = new_i_size;
1074         ret = 0;
1075 out:
1076         /*
1077          * We need to do this because we can't remove ordered extents until
1078          * after the i_disk_size has been updated and then the inode has been
1079          * updated to reflect the change, so we need to tell anybody who finds
1080          * this ordered extent that we've already done all the real work, we
1081          * just haven't completed all the other work.
1082          */
1083         if (ordered)
1084                 set_bit(BTRFS_ORDERED_UPDATED_ISIZE, &ordered->flags);
1085         spin_unlock_irq(&tree->lock);
1086         return ret;
1087 }
1088
1089 /*
1090  * search the ordered extents for one corresponding to 'offset' and
1091  * try to find a checksum.  This is used because we allow pages to
1092  * be reclaimed before their checksum is actually put into the btree
1093  */
1094 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
1095                            u32 *sum, int len)
1096 {
1097         struct btrfs_ordered_sum *ordered_sum;
1098         struct btrfs_ordered_extent *ordered;
1099         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
1100         unsigned long num_sectors;
1101         unsigned long i;
1102         u32 sectorsize = btrfs_inode_sectorsize(inode);
1103         int index = 0;
1104
1105         ordered = btrfs_lookup_ordered_extent(inode, offset);
1106         if (!ordered)
1107                 return 0;
1108
1109         spin_lock_irq(&tree->lock);
1110         list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
1111                 if (disk_bytenr >= ordered_sum->bytenr &&
1112                     disk_bytenr < ordered_sum->bytenr + ordered_sum->len) {
1113                         i = (disk_bytenr - ordered_sum->bytenr) >>
1114                             inode->i_sb->s_blocksize_bits;
1115                         num_sectors = ordered_sum->len >>
1116                                       inode->i_sb->s_blocksize_bits;
1117                         num_sectors = min_t(int, len - index, num_sectors - i);
1118                         memcpy(sum + index, ordered_sum->sums + i,
1119                                num_sectors);
1120
1121                         index += (int)num_sectors;
1122                         if (index == len)
1123                                 goto out;
1124                         disk_bytenr += num_sectors * sectorsize;
1125                 }
1126         }
1127 out:
1128         spin_unlock_irq(&tree->lock);
1129         btrfs_put_ordered_extent(ordered);
1130         return index;
1131 }
1132
1133 int __init ordered_data_init(void)
1134 {
1135         btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
1136                                      sizeof(struct btrfs_ordered_extent), 0,
1137                                      SLAB_MEM_SPREAD,
1138                                      NULL);
1139         if (!btrfs_ordered_extent_cache)
1140                 return -ENOMEM;
1141
1142         return 0;
1143 }
1144
1145 void ordered_data_exit(void)
1146 {
1147         kmem_cache_destroy(btrfs_ordered_extent_cache);
1148 }