fs/btrfs/ordered-data.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2007 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/slab.h>
   7 #include <linux/blkdev.h>
   8 #include <linux/writeback.h>
   9 #include <linux/sched/mm.h>
  10 #include "messages.h"
  11 #include "misc.h"
  12 #include "ctree.h"
  13 #include "transaction.h"
  14 #include "btrfs_inode.h"
  15 #include "extent_io.h"
  16 #include "disk-io.h"
  17 #include "compression.h"
  18 #include "delalloc-space.h"
  19 #include "qgroup.h"
  20 #include "subpage.h"
  21 #include "file.h"
  22 #include "super.h"
  23
  24 static struct kmem_cache *btrfs_ordered_extent_cache;
  25
  26 static u64 entry_end(struct btrfs_ordered_extent *entry)
  27 {
  28         if (entry->file_offset + entry->num_bytes < entry->file_offset)
  29                 return (u64)-1;
  30         return entry->file_offset + entry->num_bytes;
  31 }
  32
  33 /* returns NULL if the insertion worked, or it returns the node it did find
  34  * in the tree
  35  */
  36 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  37                                    struct rb_node *node)
  38 {
  39         struct rb_node **p = &root->rb_node;
  40         struct rb_node *parent = NULL;
  41         struct btrfs_ordered_extent *entry;
  42
  43         while (*p) {
  44                 parent = *p;
  45                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  46
  47                 if (file_offset < entry->file_offset)
  48                         p = &(*p)->rb_left;
  49                 else if (file_offset >= entry_end(entry))
  50                         p = &(*p)->rb_right;
  51                 else
  52                         return parent;
  53         }
  54
  55         rb_link_node(node, parent, p);
  56         rb_insert_color(node, root);
  57         return NULL;
  58 }
  59
  60 /*
  61  * look for a given offset in the tree, and if it can't be found return the
  62  * first lesser offset
  63  */
  64 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  65                                      struct rb_node **prev_ret)
  66 {
  67         struct rb_node *n = root->rb_node;
  68         struct rb_node *prev = NULL;
  69         struct rb_node *test;
  70         struct btrfs_ordered_extent *entry;
  71         struct btrfs_ordered_extent *prev_entry = NULL;
  72
  73         while (n) {
  74                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  75                 prev = n;
  76                 prev_entry = entry;
  77
  78                 if (file_offset < entry->file_offset)
  79                         n = n->rb_left;
  80                 else if (file_offset >= entry_end(entry))
  81                         n = n->rb_right;
  82                 else
  83                         return n;
  84         }
  85         if (!prev_ret)
  86                 return NULL;
  87
  88         while (prev && file_offset >= entry_end(prev_entry)) {
  89                 test = rb_next(prev);
  90                 if (!test)
  91                         break;
  92                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
  93                                       rb_node);
  94                 if (file_offset < entry_end(prev_entry))
  95                         break;
  96
  97                 prev = test;
  98         }
  99         if (prev)
 100                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
 101                                       rb_node);
 102         while (prev && file_offset < entry_end(prev_entry)) {
 103                 test = rb_prev(prev);
 104                 if (!test)
 105                         break;
 106                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 107                                       rb_node);
 108                 prev = test;
 109         }
 110         *prev_ret = prev;
 111         return NULL;
 112 }
 113
 114 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 115                           u64 len)
 116 {
 117         if (file_offset + len <= entry->file_offset ||
 118             entry->file_offset + entry->num_bytes <= file_offset)
 119                 return 0;
 120         return 1;
 121 }
 122
 123 /*
 124  * look find the first ordered struct that has this offset, otherwise
 125  * the first one less than this offset
 126  */
 127 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 128                                           u64 file_offset)
 129 {
 130         struct rb_root *root = &tree->tree;
 131         struct rb_node *prev = NULL;
 132         struct rb_node *ret;
 133         struct btrfs_ordered_extent *entry;
 134
 135         if (tree->last) {
 136                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 137                                  rb_node);
 138                 if (in_range(file_offset, entry->file_offset, entry->num_bytes))
 139                         return tree->last;
 140         }
 141         ret = __tree_search(root, file_offset, &prev);
 142         if (!ret)
 143                 ret = prev;
 144         if (ret)
 145                 tree->last = ret;
 146         return ret;
 147 }
 148
 149 static struct btrfs_ordered_extent *alloc_ordered_extent(
 150                         struct btrfs_inode *inode, u64 file_offset, u64 num_bytes,
 151                         u64 ram_bytes, u64 disk_bytenr, u64 disk_num_bytes,
 152                         u64 offset, unsigned long flags, int compress_type)
 153 {
 154         struct btrfs_ordered_extent *entry;
 155         int ret;
 156         u64 qgroup_rsv = 0;
 157
 158         if (flags &
 159             ((1 << BTRFS_ORDERED_NOCOW) | (1 << BTRFS_ORDERED_PREALLOC))) {
 160                 /* For nocow write, we can release the qgroup rsv right now */
 161                 ret = btrfs_qgroup_free_data(inode, NULL, file_offset, num_bytes, &qgroup_rsv);
 162                 if (ret < 0)
 163                         return ERR_PTR(ret);
 164         } else {
 165                 /*
 166                  * The ordered extent has reserved qgroup space, release now
 167                  * and pass the reserved number for qgroup_record to free.
 168                  */
 169                 ret = btrfs_qgroup_release_data(inode, file_offset, num_bytes, &qgroup_rsv);
 170                 if (ret < 0)
 171                         return ERR_PTR(ret);
 172         }
 173         entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 174         if (!entry)
 175                 return ERR_PTR(-ENOMEM);
 176
 177         entry->file_offset = file_offset;
 178         entry->num_bytes = num_bytes;
 179         entry->ram_bytes = ram_bytes;
 180         entry->disk_bytenr = disk_bytenr;
 181         entry->disk_num_bytes = disk_num_bytes;
 182         entry->offset = offset;
 183         entry->bytes_left = num_bytes;
 184         entry->inode = igrab(&inode->vfs_inode);
 185         entry->compress_type = compress_type;
 186         entry->truncated_len = (u64)-1;
 187         entry->qgroup_rsv = qgroup_rsv;
 188         entry->flags = flags;
 189         refcount_set(&entry->refs, 1);
 190         init_waitqueue_head(&entry->wait);
 191         INIT_LIST_HEAD(&entry->list);
 192         INIT_LIST_HEAD(&entry->log_list);
 193         INIT_LIST_HEAD(&entry->root_extent_list);
 194         INIT_LIST_HEAD(&entry->work_list);
 195         init_completion(&entry->completion);
 196
 197         /*
 198          * We don't need the count_max_extents here, we can assume that all of
 199          * that work has been done at higher layers, so this is truly the
 200          * smallest the extent is going to get.
 201          */
 202         spin_lock(&inode->lock);
 203         btrfs_mod_outstanding_extents(inode, 1);
 204         spin_unlock(&inode->lock);
 205
 206         return entry;
 207 }
 208
 209 static void insert_ordered_extent(struct btrfs_ordered_extent *entry)
 210 {
 211         struct btrfs_inode *inode = BTRFS_I(entry->inode);
 212         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 213         struct btrfs_root *root = inode->root;
 214         struct btrfs_fs_info *fs_info = root->fs_info;
 215         struct rb_node *node;
 216
 217         trace_btrfs_ordered_extent_add(inode, entry);
 218
 219         percpu_counter_add_batch(&fs_info->ordered_bytes, entry->num_bytes,
 220                                  fs_info->delalloc_batch);
 221
 222         /* One ref for the tree. */
 223         refcount_inc(&entry->refs);
 224
 225         spin_lock_irq(&tree->lock);
 226         node = tree_insert(&tree->tree, entry->file_offset, &entry->rb_node);
 227         if (node)
 228                 btrfs_panic(fs_info, -EEXIST,
 229                                 "inconsistency in ordered tree at offset %llu",
 230                                 entry->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
 246 /*
 247  * Add an ordered extent to the per-inode tree.
 248  *
 249  * @inode:           Inode that this extent is for.
 250  * @file_offset:     Logical offset in file where the extent starts.
 251  * @num_bytes:       Logical length of extent in file.
 252  * @ram_bytes:       Full length of unencoded data.
 253  * @disk_bytenr:     Offset of extent on disk.
 254  * @disk_num_bytes:  Size of extent on disk.
 255  * @offset:          Offset into unencoded data where file data starts.
 256  * @flags:           Flags specifying type of extent (1 << BTRFS_ORDERED_*).
 257  * @compress_type:   Compression algorithm used for data.
 258  *
 259  * Most of these parameters correspond to &struct btrfs_file_extent_item. The
 260  * tree is given a single reference on the ordered extent that was inserted, and
 261  * the returned pointer is given a second reference.
 262  *
 263  * Return: the new ordered extent or error pointer.
 264  */
 265 struct btrfs_ordered_extent *btrfs_alloc_ordered_extent(
 266                         struct btrfs_inode *inode, u64 file_offset,
 267                         u64 num_bytes, u64 ram_bytes, u64 disk_bytenr,
 268                         u64 disk_num_bytes, u64 offset, unsigned long flags,
 269                         int compress_type)
 270 {
 271         struct btrfs_ordered_extent *entry;
 272
 273         ASSERT((flags & ~BTRFS_ORDERED_TYPE_FLAGS) == 0);
 274
 275         entry = alloc_ordered_extent(inode, file_offset, num_bytes, ram_bytes,
 276                                      disk_bytenr, disk_num_bytes, offset, flags,
 277                                      compress_type);
 278         if (!IS_ERR(entry))
 279                 insert_ordered_extent(entry);
 280         return entry;
 281 }
 282
 283 /*
 284  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 285  * when an ordered extent is finished.  If the list covers more than one
 286  * ordered extent, it is split across multiples.
 287  */
 288 void btrfs_add_ordered_sum(struct btrfs_ordered_extent *entry,
 289                            struct btrfs_ordered_sum *sum)
 290 {
 291         struct btrfs_ordered_inode_tree *tree;
 292
 293         tree = &BTRFS_I(entry->inode)->ordered_tree;
 294         spin_lock_irq(&tree->lock);
 295         list_add_tail(&sum->list, &entry->list);
 296         spin_unlock_irq(&tree->lock);
 297 }
 298
 299 static void finish_ordered_fn(struct btrfs_work *work)
 300 {
 301         struct btrfs_ordered_extent *ordered_extent;
 302
 303         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
 304         btrfs_finish_ordered_io(ordered_extent);
 305 }
 306
 307 static bool can_finish_ordered_extent(struct btrfs_ordered_extent *ordered,
 308                                       struct page *page, u64 file_offset,
 309                                       u64 len, bool uptodate)
 310 {
 311         struct btrfs_inode *inode = BTRFS_I(ordered->inode);
 312         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 313
 314         lockdep_assert_held(&inode->ordered_tree.lock);
 315
 316         if (page) {
 317                 ASSERT(page->mapping);
 318                 ASSERT(page_offset(page) <= file_offset);
 319                 ASSERT(file_offset + len <= page_offset(page) + PAGE_SIZE);
 320
 321                 /*
 322                  * Ordered (Private2) bit indicates whether we still have
 323                  * pending io unfinished for the ordered extent.
 324                  *
 325                  * If there's no such bit, we need to skip to next range.
 326                  */
 327                 if (!btrfs_page_test_ordered(fs_info, page, file_offset, len))
 328                         return false;
 329                 btrfs_page_clear_ordered(fs_info, page, file_offset, len);
 330         }
 331
 332         /* Now we're fine to update the accounting. */
 333         if (WARN_ON_ONCE(len > ordered->bytes_left)) {
 334                 btrfs_crit(fs_info,
 335 "bad ordered extent accounting, root=%llu ino=%llu OE offset=%llu OE len=%llu to_dec=%llu left=%llu",
 336                            inode->root->root_key.objectid, btrfs_ino(inode),
 337                            ordered->file_offset, ordered->num_bytes,
 338                            len, ordered->bytes_left);
 339                 ordered->bytes_left = 0;
 340         } else {
 341                 ordered->bytes_left -= len;
 342         }
 343
 344         if (!uptodate)
 345                 set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
 346
 347         if (ordered->bytes_left)
 348                 return false;
 349
 350         /*
 351          * All the IO of the ordered extent is finished, we need to queue
 352          * the finish_func to be executed.
 353          */
 354         set_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags);
 355         cond_wake_up(&ordered->wait);
 356         refcount_inc(&ordered->refs);
 357         trace_btrfs_ordered_extent_mark_finished(inode, ordered);
 358         return true;
 359 }
 360
 361 static void btrfs_queue_ordered_fn(struct btrfs_ordered_extent *ordered)
 362 {
 363         struct btrfs_inode *inode = BTRFS_I(ordered->inode);
 364         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 365         struct btrfs_workqueue *wq = btrfs_is_free_space_inode(inode) ?
 366                 fs_info->endio_freespace_worker : fs_info->endio_write_workers;
 367
 368         btrfs_init_work(&ordered->work, finish_ordered_fn, NULL, NULL);
 369         btrfs_queue_work(wq, &ordered->work);
 370 }
 371
 372 bool btrfs_finish_ordered_extent(struct btrfs_ordered_extent *ordered,
 373                                  struct page *page, u64 file_offset, u64 len,
 374                                  bool uptodate)
 375 {
 376         struct btrfs_inode *inode = BTRFS_I(ordered->inode);
 377         unsigned long flags;
 378         bool ret;
 379
 380         trace_btrfs_finish_ordered_extent(inode, file_offset, len, uptodate);
 381
 382         spin_lock_irqsave(&inode->ordered_tree.lock, flags);
 383         ret = can_finish_ordered_extent(ordered, page, file_offset, len, uptodate);
 384         spin_unlock_irqrestore(&inode->ordered_tree.lock, flags);
 385
 386         if (ret)
 387                 btrfs_queue_ordered_fn(ordered);
 388         return ret;
 389 }
 390
 391 /*
 392  * Mark all ordered extents io inside the specified range finished.
 393  *
 394  * @page:        The involved page for the operation.
 395  *               For uncompressed buffered IO, the page status also needs to be
 396  *               updated to indicate whether the pending ordered io is finished.
 397  *               Can be NULL for direct IO and compressed write.
 398  *               For these cases, callers are ensured they won't execute the
 399  *               endio function twice.
 400  *
 401  * This function is called for endio, thus the range must have ordered
 402  * extent(s) covering it.
 403  */
 404 void btrfs_mark_ordered_io_finished(struct btrfs_inode *inode,
 405                                     struct page *page, u64 file_offset,
 406                                     u64 num_bytes, bool uptodate)
 407 {
 408         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 409         struct rb_node *node;
 410         struct btrfs_ordered_extent *entry = NULL;
 411         unsigned long flags;
 412         u64 cur = file_offset;
 413
 414         trace_btrfs_writepage_end_io_hook(inode, file_offset,
 415                                           file_offset + num_bytes - 1,
 416                                           uptodate);
 417
 418         spin_lock_irqsave(&tree->lock, flags);
 419         while (cur < file_offset + num_bytes) {
 420                 u64 entry_end;
 421                 u64 end;
 422                 u32 len;
 423
 424                 node = tree_search(tree, cur);
 425                 /* No ordered extents at all */
 426                 if (!node)
 427                         break;
 428
 429                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 430                 entry_end = entry->file_offset + entry->num_bytes;
 431                 /*
 432                  * |<-- OE --->|  |
 433                  *                cur
 434                  * Go to next OE.
 435                  */
 436                 if (cur >= entry_end) {
 437                         node = rb_next(node);
 438                         /* No more ordered extents, exit */
 439                         if (!node)
 440                                 break;
 441                         entry = rb_entry(node, struct btrfs_ordered_extent,
 442                                          rb_node);
 443
 444                         /* Go to next ordered extent and continue */
 445                         cur = entry->file_offset;
 446                         continue;
 447                 }
 448                 /*
 449                  * |    |<--- OE --->|
 450                  * cur
 451                  * Go to the start of OE.
 452                  */
 453                 if (cur < entry->file_offset) {
 454                         cur = entry->file_offset;
 455                         continue;
 456                 }
 457
 458                 /*
 459                  * Now we are definitely inside one ordered extent.
 460                  *
 461                  * |<--- OE --->|
 462                  *      |
 463                  *      cur
 464                  */
 465                 end = min(entry->file_offset + entry->num_bytes,
 466                           file_offset + num_bytes) - 1;
 467                 ASSERT(end + 1 - cur < U32_MAX);
 468                 len = end + 1 - cur;
 469
 470                 if (can_finish_ordered_extent(entry, page, cur, len, uptodate)) {
 471                         spin_unlock_irqrestore(&tree->lock, flags);
 472                         btrfs_queue_ordered_fn(entry);
 473                         spin_lock_irqsave(&tree->lock, flags);
 474                 }
 475                 cur += len;
 476         }
 477         spin_unlock_irqrestore(&tree->lock, flags);
 478 }
 479
 480 /*
 481  * Finish IO for one ordered extent across a given range.  The range can only
 482  * contain one ordered extent.
 483  *
 484  * @cached:      The cached ordered extent. If not NULL, we can skip the tree
 485  *               search and use the ordered extent directly.
 486  *               Will be also used to store the finished ordered extent.
 487  * @file_offset: File offset for the finished IO
 488  * @io_size:     Length of the finish IO range
 489  *
 490  * Return true if the ordered extent is finished in the range, and update
 491  * @cached.
 492  * Return false otherwise.
 493  *
 494  * NOTE: The range can NOT cross multiple ordered extents.
 495  * Thus caller should ensure the range doesn't cross ordered extents.
 496  */
 497 bool btrfs_dec_test_ordered_pending(struct btrfs_inode *inode,
 498                                     struct btrfs_ordered_extent **cached,
 499                                     u64 file_offset, u64 io_size)
 500 {
 501         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 502         struct rb_node *node;
 503         struct btrfs_ordered_extent *entry = NULL;
 504         unsigned long flags;
 505         bool finished = false;
 506
 507         spin_lock_irqsave(&tree->lock, flags);
 508         if (cached && *cached) {
 509                 entry = *cached;
 510                 goto have_entry;
 511         }
 512
 513         node = tree_search(tree, file_offset);
 514         if (!node)
 515                 goto out;
 516
 517         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 518 have_entry:
 519         if (!in_range(file_offset, entry->file_offset, entry->num_bytes))
 520                 goto out;
 521
 522         if (io_size > entry->bytes_left)
 523                 btrfs_crit(inode->root->fs_info,
 524                            "bad ordered accounting left %llu size %llu",
 525                        entry->bytes_left, io_size);
 526
 527         entry->bytes_left -= io_size;
 528
 529         if (entry->bytes_left == 0) {
 530                 /*
 531                  * Ensure only one caller can set the flag and finished_ret
 532                  * accordingly
 533                  */
 534                 finished = !test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 535                 /* test_and_set_bit implies a barrier */
 536                 cond_wake_up_nomb(&entry->wait);
 537         }
 538 out:
 539         if (finished && cached && entry) {
 540                 *cached = entry;
 541                 refcount_inc(&entry->refs);
 542                 trace_btrfs_ordered_extent_dec_test_pending(inode, entry);
 543         }
 544         spin_unlock_irqrestore(&tree->lock, flags);
 545         return finished;
 546 }
 547
 548 /*
 549  * used to drop a reference on an ordered extent.  This will free
 550  * the extent if the last reference is dropped
 551  */
 552 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 553 {
 554         struct list_head *cur;
 555         struct btrfs_ordered_sum *sum;
 556
 557         trace_btrfs_ordered_extent_put(BTRFS_I(entry->inode), entry);
 558
 559         if (refcount_dec_and_test(&entry->refs)) {
 560                 ASSERT(list_empty(&entry->root_extent_list));
 561                 ASSERT(list_empty(&entry->log_list));
 562                 ASSERT(RB_EMPTY_NODE(&entry->rb_node));
 563                 if (entry->inode)
 564                         btrfs_add_delayed_iput(BTRFS_I(entry->inode));
 565                 while (!list_empty(&entry->list)) {
 566                         cur = entry->list.next;
 567                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 568                         list_del(&sum->list);
 569                         kvfree(sum);
 570                 }
 571                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
 572         }
 573 }
 574
 575 /*
 576  * remove an ordered extent from the tree.  No references are dropped
 577  * and waiters are woken up.
 578  */
 579 void btrfs_remove_ordered_extent(struct btrfs_inode *btrfs_inode,
 580                                  struct btrfs_ordered_extent *entry)
 581 {
 582         struct btrfs_ordered_inode_tree *tree;
 583         struct btrfs_root *root = btrfs_inode->root;
 584         struct btrfs_fs_info *fs_info = root->fs_info;
 585         struct rb_node *node;
 586         bool pending;
 587         bool freespace_inode;
 588
 589         /*
 590          * If this is a free space inode the thread has not acquired the ordered
 591          * extents lockdep map.
 592          */
 593         freespace_inode = btrfs_is_free_space_inode(btrfs_inode);
 594
 595         btrfs_lockdep_acquire(fs_info, btrfs_trans_pending_ordered);
 596         /* This is paired with btrfs_alloc_ordered_extent. */
 597         spin_lock(&btrfs_inode->lock);
 598         btrfs_mod_outstanding_extents(btrfs_inode, -1);
 599         spin_unlock(&btrfs_inode->lock);
 600         if (root != fs_info->tree_root) {
 601                 u64 release;
 602
 603                 if (test_bit(BTRFS_ORDERED_ENCODED, &entry->flags))
 604                         release = entry->disk_num_bytes;
 605                 else
 606                         release = entry->num_bytes;
 607                 btrfs_delalloc_release_metadata(btrfs_inode, release,
 608                                                 test_bit(BTRFS_ORDERED_IOERR,
 609                                                          &entry->flags));
 610         }
 611
 612         percpu_counter_add_batch(&fs_info->ordered_bytes, -entry->num_bytes,
 613                                  fs_info->delalloc_batch);
 614
 615         tree = &btrfs_inode->ordered_tree;
 616         spin_lock_irq(&tree->lock);
 617         node = &entry->rb_node;
 618         rb_erase(node, &tree->tree);
 619         RB_CLEAR_NODE(node);
 620         if (tree->last == node)
 621                 tree->last = NULL;
 622         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 623         pending = test_and_clear_bit(BTRFS_ORDERED_PENDING, &entry->flags);
 624         spin_unlock_irq(&tree->lock);
 625
 626         /*
 627          * The current running transaction is waiting on us, we need to let it
 628          * know that we're complete and wake it up.
 629          */
 630         if (pending) {
 631                 struct btrfs_transaction *trans;
 632
 633                 /*
 634                  * The checks for trans are just a formality, it should be set,
 635                  * but if it isn't we don't want to deref/assert under the spin
 636                  * lock, so be nice and check if trans is set, but ASSERT() so
 637                  * if it isn't set a developer will notice.
 638                  */
 639                 spin_lock(&fs_info->trans_lock);
 640                 trans = fs_info->running_transaction;
 641                 if (trans)
 642                         refcount_inc(&trans->use_count);
 643                 spin_unlock(&fs_info->trans_lock);
 644
 645                 ASSERT(trans || BTRFS_FS_ERROR(fs_info));
 646                 if (trans) {
 647                         if (atomic_dec_and_test(&trans->pending_ordered))
 648                                 wake_up(&trans->pending_wait);
 649                         btrfs_put_transaction(trans);
 650                 }
 651         }
 652
 653         btrfs_lockdep_release(fs_info, btrfs_trans_pending_ordered);
 654
 655         spin_lock(&root->ordered_extent_lock);
 656         list_del_init(&entry->root_extent_list);
 657         root->nr_ordered_extents--;
 658
 659         trace_btrfs_ordered_extent_remove(btrfs_inode, entry);
 660
 661         if (!root->nr_ordered_extents) {
 662                 spin_lock(&fs_info->ordered_root_lock);
 663                 BUG_ON(list_empty(&root->ordered_root));
 664                 list_del_init(&root->ordered_root);
 665                 spin_unlock(&fs_info->ordered_root_lock);
 666         }
 667         spin_unlock(&root->ordered_extent_lock);
 668         wake_up(&entry->wait);
 669         if (!freespace_inode)
 670                 btrfs_lockdep_release(fs_info, btrfs_ordered_extent);
 671 }
 672
 673 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 674 {
 675         struct btrfs_ordered_extent *ordered;
 676
 677         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 678         btrfs_start_ordered_extent(ordered);
 679         complete(&ordered->completion);
 680 }
 681
 682 /*
 683  * wait for all the ordered extents in a root.  This is done when balancing
 684  * space between drives.
 685  */
 686 u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
 687                                const u64 range_start, const u64 range_len)
 688 {
 689         struct btrfs_fs_info *fs_info = root->fs_info;
 690         LIST_HEAD(splice);
 691         LIST_HEAD(skipped);
 692         LIST_HEAD(works);
 693         struct btrfs_ordered_extent *ordered, *next;
 694         u64 count = 0;
 695         const u64 range_end = range_start + range_len;
 696
 697         mutex_lock(&root->ordered_extent_mutex);
 698         spin_lock(&root->ordered_extent_lock);
 699         list_splice_init(&root->ordered_extents, &splice);
 700         while (!list_empty(&splice) && nr) {
 701                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 702                                            root_extent_list);
 703
 704                 if (range_end <= ordered->disk_bytenr ||
 705                     ordered->disk_bytenr + ordered->disk_num_bytes <= range_start) {
 706                         list_move_tail(&ordered->root_extent_list, &skipped);
 707                         cond_resched_lock(&root->ordered_extent_lock);
 708                         continue;
 709                 }
 710
 711                 list_move_tail(&ordered->root_extent_list,
 712                                &root->ordered_extents);
 713                 refcount_inc(&ordered->refs);
 714                 spin_unlock(&root->ordered_extent_lock);
 715
 716                 btrfs_init_work(&ordered->flush_work,
 717                                 btrfs_run_ordered_extent_work, NULL, NULL);
 718                 list_add_tail(&ordered->work_list, &works);
 719                 btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work);
 720
 721                 cond_resched();
 722                 spin_lock(&root->ordered_extent_lock);
 723                 if (nr != U64_MAX)
 724                         nr--;
 725                 count++;
 726         }
 727         list_splice_tail(&skipped, &root->ordered_extents);
 728         list_splice_tail(&splice, &root->ordered_extents);
 729         spin_unlock(&root->ordered_extent_lock);
 730
 731         list_for_each_entry_safe(ordered, next, &works, work_list) {
 732                 list_del_init(&ordered->work_list);
 733                 wait_for_completion(&ordered->completion);
 734                 btrfs_put_ordered_extent(ordered);
 735                 cond_resched();
 736         }
 737         mutex_unlock(&root->ordered_extent_mutex);
 738
 739         return count;
 740 }
 741
 742 void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
 743                              const u64 range_start, const u64 range_len)
 744 {
 745         struct btrfs_root *root;
 746         LIST_HEAD(splice);
 747         u64 done;
 748
 749         mutex_lock(&fs_info->ordered_operations_mutex);
 750         spin_lock(&fs_info->ordered_root_lock);
 751         list_splice_init(&fs_info->ordered_roots, &splice);
 752         while (!list_empty(&splice) && nr) {
 753                 root = list_first_entry(&splice, struct btrfs_root,
 754                                         ordered_root);
 755                 root = btrfs_grab_root(root);
 756                 BUG_ON(!root);
 757                 list_move_tail(&root->ordered_root,
 758                                &fs_info->ordered_roots);
 759                 spin_unlock(&fs_info->ordered_root_lock);
 760
 761                 done = btrfs_wait_ordered_extents(root, nr,
 762                                                   range_start, range_len);
 763                 btrfs_put_root(root);
 764
 765                 spin_lock(&fs_info->ordered_root_lock);
 766                 if (nr != U64_MAX) {
 767                         nr -= done;
 768                 }
 769         }
 770         list_splice_tail(&splice, &fs_info->ordered_roots);
 771         spin_unlock(&fs_info->ordered_root_lock);
 772         mutex_unlock(&fs_info->ordered_operations_mutex);
 773 }
 774
 775 /*
 776  * Start IO and wait for a given ordered extent to finish.
 777  *
 778  * Wait on page writeback for all the pages in the extent and the IO completion
 779  * code to insert metadata into the btree corresponding to the extent.
 780  */
 781 void btrfs_start_ordered_extent(struct btrfs_ordered_extent *entry)
 782 {
 783         u64 start = entry->file_offset;
 784         u64 end = start + entry->num_bytes - 1;
 785         struct btrfs_inode *inode = BTRFS_I(entry->inode);
 786         bool freespace_inode;
 787
 788         trace_btrfs_ordered_extent_start(inode, entry);
 789
 790         /*
 791          * If this is a free space inode do not take the ordered extents lockdep
 792          * map.
 793          */
 794         freespace_inode = btrfs_is_free_space_inode(inode);
 795
 796         /*
 797          * pages in the range can be dirty, clean or writeback.  We
 798          * start IO on any dirty ones so the wait doesn't stall waiting
 799          * for the flusher thread to find them
 800          */
 801         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 802                 filemap_fdatawrite_range(inode->vfs_inode.i_mapping, start, end);
 803
 804         if (!freespace_inode)
 805                 btrfs_might_wait_for_event(inode->root->fs_info, btrfs_ordered_extent);
 806         wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE, &entry->flags));
 807 }
 808
 809 /*
 810  * Used to wait on ordered extents across a large range of bytes.
 811  */
 812 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 813 {
 814         int ret = 0;
 815         int ret_wb = 0;
 816         u64 end;
 817         u64 orig_end;
 818         struct btrfs_ordered_extent *ordered;
 819
 820         if (start + len < start) {
 821                 orig_end = OFFSET_MAX;
 822         } else {
 823                 orig_end = start + len - 1;
 824                 if (orig_end > OFFSET_MAX)
 825                         orig_end = OFFSET_MAX;
 826         }
 827
 828         /* start IO across the range first to instantiate any delalloc
 829          * extents
 830          */
 831         ret = btrfs_fdatawrite_range(inode, start, orig_end);
 832         if (ret)
 833                 return ret;
 834
 835         /*
 836          * If we have a writeback error don't return immediately. Wait first
 837          * for any ordered extents that haven't completed yet. This is to make
 838          * sure no one can dirty the same page ranges and call writepages()
 839          * before the ordered extents complete - to avoid failures (-EEXIST)
 840          * when adding the new ordered extents to the ordered tree.
 841          */
 842         ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 843
 844         end = orig_end;
 845         while (1) {
 846                 ordered = btrfs_lookup_first_ordered_extent(BTRFS_I(inode), end);
 847                 if (!ordered)
 848                         break;
 849                 if (ordered->file_offset > orig_end) {
 850                         btrfs_put_ordered_extent(ordered);
 851                         break;
 852                 }
 853                 if (ordered->file_offset + ordered->num_bytes <= start) {
 854                         btrfs_put_ordered_extent(ordered);
 855                         break;
 856                 }
 857                 btrfs_start_ordered_extent(ordered);
 858                 end = ordered->file_offset;
 859                 /*
 860                  * If the ordered extent had an error save the error but don't
 861                  * exit without waiting first for all other ordered extents in
 862                  * the range to complete.
 863                  */
 864                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 865                         ret = -EIO;
 866                 btrfs_put_ordered_extent(ordered);
 867                 if (end == 0 || end == start)
 868                         break;
 869                 end--;
 870         }
 871         return ret_wb ? ret_wb : ret;
 872 }
 873
 874 /*
 875  * find an ordered extent corresponding to file_offset.  return NULL if
 876  * nothing is found, otherwise take a reference on the extent and return it
 877  */
 878 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct btrfs_inode *inode,
 879                                                          u64 file_offset)
 880 {
 881         struct btrfs_ordered_inode_tree *tree;
 882         struct rb_node *node;
 883         struct btrfs_ordered_extent *entry = NULL;
 884         unsigned long flags;
 885
 886         tree = &inode->ordered_tree;
 887         spin_lock_irqsave(&tree->lock, flags);
 888         node = tree_search(tree, file_offset);
 889         if (!node)
 890                 goto out;
 891
 892         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 893         if (!in_range(file_offset, entry->file_offset, entry->num_bytes))
 894                 entry = NULL;
 895         if (entry) {
 896                 refcount_inc(&entry->refs);
 897                 trace_btrfs_ordered_extent_lookup(inode, entry);
 898         }
 899 out:
 900         spin_unlock_irqrestore(&tree->lock, flags);
 901         return entry;
 902 }
 903
 904 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 905  * extents that exist in the range, rather than just the start of the range.
 906  */
 907 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
 908                 struct btrfs_inode *inode, u64 file_offset, u64 len)
 909 {
 910         struct btrfs_ordered_inode_tree *tree;
 911         struct rb_node *node;
 912         struct btrfs_ordered_extent *entry = NULL;
 913
 914         tree = &inode->ordered_tree;
 915         spin_lock_irq(&tree->lock);
 916         node = tree_search(tree, file_offset);
 917         if (!node) {
 918                 node = tree_search(tree, file_offset + len);
 919                 if (!node)
 920                         goto out;
 921         }
 922
 923         while (1) {
 924                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 925                 if (range_overlaps(entry, file_offset, len))
 926                         break;
 927
 928                 if (entry->file_offset >= file_offset + len) {
 929                         entry = NULL;
 930                         break;
 931                 }
 932                 entry = NULL;
 933                 node = rb_next(node);
 934                 if (!node)
 935                         break;
 936         }
 937 out:
 938         if (entry) {
 939                 refcount_inc(&entry->refs);
 940                 trace_btrfs_ordered_extent_lookup_range(inode, entry);
 941         }
 942         spin_unlock_irq(&tree->lock);
 943         return entry;
 944 }
 945
 946 /*
 947  * Adds all ordered extents to the given list. The list ends up sorted by the
 948  * file_offset of the ordered extents.
 949  */
 950 void btrfs_get_ordered_extents_for_logging(struct btrfs_inode *inode,
 951                                            struct list_head *list)
 952 {
 953         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 954         struct rb_node *n;
 955
 956         ASSERT(inode_is_locked(&inode->vfs_inode));
 957
 958         spin_lock_irq(&tree->lock);
 959         for (n = rb_first(&tree->tree); n; n = rb_next(n)) {
 960                 struct btrfs_ordered_extent *ordered;
 961
 962                 ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
 963
 964                 if (test_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
 965                         continue;
 966
 967                 ASSERT(list_empty(&ordered->log_list));
 968                 list_add_tail(&ordered->log_list, list);
 969                 refcount_inc(&ordered->refs);
 970                 trace_btrfs_ordered_extent_lookup_for_logging(inode, ordered);
 971         }
 972         spin_unlock_irq(&tree->lock);
 973 }
 974
 975 /*
 976  * lookup and return any extent before 'file_offset'.  NULL is returned
 977  * if none is found
 978  */
 979 struct btrfs_ordered_extent *
 980 btrfs_lookup_first_ordered_extent(struct btrfs_inode *inode, u64 file_offset)
 981 {
 982         struct btrfs_ordered_inode_tree *tree;
 983         struct rb_node *node;
 984         struct btrfs_ordered_extent *entry = NULL;
 985
 986         tree = &inode->ordered_tree;
 987         spin_lock_irq(&tree->lock);
 988         node = tree_search(tree, file_offset);
 989         if (!node)
 990                 goto out;
 991
 992         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 993         refcount_inc(&entry->refs);
 994         trace_btrfs_ordered_extent_lookup_first(inode, entry);
 995 out:
 996         spin_unlock_irq(&tree->lock);
 997         return entry;
 998 }
 999
1000 /*
1001  * Lookup the first ordered extent that overlaps the range
1002  * [@file_offset, @file_offset + @len).
1003  *
1004  * The difference between this and btrfs_lookup_first_ordered_extent() is
1005  * that this one won't return any ordered extent that does not overlap the range.
1006  * And the difference against btrfs_lookup_ordered_extent() is, this function
1007  * ensures the first ordered extent gets returned.
1008  */
1009 struct btrfs_ordered_extent *btrfs_lookup_first_ordered_range(
1010                         struct btrfs_inode *inode, u64 file_offset, u64 len)
1011 {
1012         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
1013         struct rb_node *node;
1014         struct rb_node *cur;
1015         struct rb_node *prev;
1016         struct rb_node *next;
1017         struct btrfs_ordered_extent *entry = NULL;
1018
1019         spin_lock_irq(&tree->lock);
1020         node = tree->tree.rb_node;
1021         /*
1022          * Here we don't want to use tree_search() which will use tree->last
1023          * and screw up the search order.
1024          * And __tree_search() can't return the adjacent ordered extents
1025          * either, thus here we do our own search.
1026          */
1027         while (node) {
1028                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
1029
1030                 if (file_offset < entry->file_offset) {
1031                         node = node->rb_left;
1032                 } else if (file_offset >= entry_end(entry)) {
1033                         node = node->rb_right;
1034                 } else {
1035                         /*
1036                          * Direct hit, got an ordered extent that starts at
1037                          * @file_offset
1038                          */
1039                         goto out;
1040                 }
1041         }
1042         if (!entry) {
1043                 /* Empty tree */
1044                 goto out;
1045         }
1046
1047         cur = &entry->rb_node;
1048         /* We got an entry around @file_offset, check adjacent entries */
1049         if (entry->file_offset < file_offset) {
1050                 prev = cur;
1051                 next = rb_next(cur);
1052         } else {
1053                 prev = rb_prev(cur);
1054                 next = cur;
1055         }
1056         if (prev) {
1057                 entry = rb_entry(prev, struct btrfs_ordered_extent, rb_node);
1058                 if (range_overlaps(entry, file_offset, len))
1059                         goto out;
1060         }
1061         if (next) {
1062                 entry = rb_entry(next, struct btrfs_ordered_extent, rb_node);
1063                 if (range_overlaps(entry, file_offset, len))
1064                         goto out;
1065         }
1066         /* No ordered extent in the range */
1067         entry = NULL;
1068 out:
1069         if (entry) {
1070                 refcount_inc(&entry->refs);
1071                 trace_btrfs_ordered_extent_lookup_first_range(inode, entry);
1072         }
1073
1074         spin_unlock_irq(&tree->lock);
1075         return entry;
1076 }
1077
1078 /*
1079  * Lock the passed range and ensures all pending ordered extents in it are run
1080  * to completion.
1081  *
1082  * @inode:        Inode whose ordered tree is to be searched
1083  * @start:        Beginning of range to flush
1084  * @end:          Last byte of range to lock
1085  * @cached_state: If passed, will return the extent state responsible for the
1086  *                locked range. It's the caller's responsibility to free the
1087  *                cached state.
1088  *
1089  * Always return with the given range locked, ensuring after it's called no
1090  * order extent can be pending.
1091  */
1092 void btrfs_lock_and_flush_ordered_range(struct btrfs_inode *inode, u64 start,
1093                                         u64 end,
1094                                         struct extent_state **cached_state)
1095 {
1096         struct btrfs_ordered_extent *ordered;
1097         struct extent_state *cache = NULL;
1098         struct extent_state **cachedp = &cache;
1099
1100         if (cached_state)
1101                 cachedp = cached_state;
1102
1103         while (1) {
1104                 lock_extent(&inode->io_tree, start, end, cachedp);
1105                 ordered = btrfs_lookup_ordered_range(inode, start,
1106                                                      end - start + 1);
1107                 if (!ordered) {
1108                         /*
1109                          * If no external cached_state has been passed then
1110                          * decrement the extra ref taken for cachedp since we
1111                          * aren't exposing it outside of this function
1112                          */
1113                         if (!cached_state)
1114                                 refcount_dec(&cache->refs);
1115                         break;
1116                 }
1117                 unlock_extent(&inode->io_tree, start, end, cachedp);
1118                 btrfs_start_ordered_extent(ordered);
1119                 btrfs_put_ordered_extent(ordered);
1120         }
1121 }
1122
1123 /*
1124  * Lock the passed range and ensure all pending ordered extents in it are run
1125  * to completion in nowait mode.
1126  *
1127  * Return true if btrfs_lock_ordered_range does not return any extents,
1128  * otherwise false.
1129  */
1130 bool btrfs_try_lock_ordered_range(struct btrfs_inode *inode, u64 start, u64 end,
1131                                   struct extent_state **cached_state)
1132 {
1133         struct btrfs_ordered_extent *ordered;
1134
1135         if (!try_lock_extent(&inode->io_tree, start, end, cached_state))
1136                 return false;
1137
1138         ordered = btrfs_lookup_ordered_range(inode, start, end - start + 1);
1139         if (!ordered)
1140                 return true;
1141
1142         btrfs_put_ordered_extent(ordered);
1143         unlock_extent(&inode->io_tree, start, end, cached_state);
1144
1145         return false;
1146 }
1147
1148 /* Split out a new ordered extent for this first @len bytes of @ordered. */
1149 struct btrfs_ordered_extent *btrfs_split_ordered_extent(
1150                         struct btrfs_ordered_extent *ordered, u64 len)
1151 {
1152         struct btrfs_inode *inode = BTRFS_I(ordered->inode);
1153         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
1154         struct btrfs_root *root = inode->root;
1155         struct btrfs_fs_info *fs_info = root->fs_info;
1156         u64 file_offset = ordered->file_offset;
1157         u64 disk_bytenr = ordered->disk_bytenr;
1158         unsigned long flags = ordered->flags;
1159         struct btrfs_ordered_sum *sum, *tmpsum;
1160         struct btrfs_ordered_extent *new;
1161         struct rb_node *node;
1162         u64 offset = 0;
1163
1164         trace_btrfs_ordered_extent_split(inode, ordered);
1165
1166         ASSERT(!(flags & (1U << BTRFS_ORDERED_COMPRESSED)));
1167
1168         /*
1169          * The entire bio must be covered by the ordered extent, but we can't
1170          * reduce the original extent to a zero length either.
1171          */
1172         if (WARN_ON_ONCE(len >= ordered->num_bytes))
1173                 return ERR_PTR(-EINVAL);
1174         /* We cannot split partially completed ordered extents. */
1175         if (ordered->bytes_left) {
1176                 ASSERT(!(flags & ~BTRFS_ORDERED_TYPE_FLAGS));
1177                 if (WARN_ON_ONCE(ordered->bytes_left != ordered->disk_num_bytes))
1178                         return ERR_PTR(-EINVAL);
1179         }
1180         /* We cannot split a compressed ordered extent. */
1181         if (WARN_ON_ONCE(ordered->disk_num_bytes != ordered->num_bytes))
1182                 return ERR_PTR(-EINVAL);
1183
1184         new = alloc_ordered_extent(inode, file_offset, len, len, disk_bytenr,
1185                                    len, 0, flags, ordered->compress_type);
1186         if (IS_ERR(new))
1187                 return new;
1188
1189         /* One ref for the tree. */
1190         refcount_inc(&new->refs);
1191
1192         spin_lock_irq(&root->ordered_extent_lock);
1193         spin_lock(&tree->lock);
1194         /* Remove from tree once */
1195         node = &ordered->rb_node;
1196         rb_erase(node, &tree->tree);
1197         RB_CLEAR_NODE(node);
1198         if (tree->last == node)
1199                 tree->last = NULL;
1200
1201         ordered->file_offset += len;
1202         ordered->disk_bytenr += len;
1203         ordered->num_bytes -= len;
1204         ordered->disk_num_bytes -= len;
1205
1206         if (test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags)) {
1207                 ASSERT(ordered->bytes_left == 0);
1208                 new->bytes_left = 0;
1209         } else {
1210                 ordered->bytes_left -= len;
1211         }
1212
1213         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags)) {
1214                 if (ordered->truncated_len > len) {
1215                         ordered->truncated_len -= len;
1216                 } else {
1217                         new->truncated_len = ordered->truncated_len;
1218                         ordered->truncated_len = 0;
1219                 }
1220         }
1221
1222         list_for_each_entry_safe(sum, tmpsum, &ordered->list, list) {
1223                 if (offset == len)
1224                         break;
1225                 list_move_tail(&sum->list, &new->list);
1226                 offset += sum->len;
1227         }
1228
1229         /* Re-insert the node */
1230         node = tree_insert(&tree->tree, ordered->file_offset, &ordered->rb_node);
1231         if (node)
1232                 btrfs_panic(fs_info, -EEXIST,
1233                         "zoned: inconsistency in ordered tree at offset %llu",
1234                         ordered->file_offset);
1235
1236         node = tree_insert(&tree->tree, new->file_offset, &new->rb_node);
1237         if (node)
1238                 btrfs_panic(fs_info, -EEXIST,
1239                         "zoned: inconsistency in ordered tree at offset %llu",
1240                         new->file_offset);
1241         spin_unlock(&tree->lock);
1242
1243         list_add_tail(&new->root_extent_list, &root->ordered_extents);
1244         root->nr_ordered_extents++;
1245         spin_unlock_irq(&root->ordered_extent_lock);
1246         return new;
1247 }
1248
1249 int __init ordered_data_init(void)
1250 {
1251         btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
1252                                      sizeof(struct btrfs_ordered_extent), 0,
1253                                      SLAB_MEM_SPREAD,
1254                                      NULL);
1255         if (!btrfs_ordered_extent_cache)
1256                 return -ENOMEM;
1257
1258         return 0;
1259 }
1260
1261 void __cold ordered_data_exit(void)
1262 {
1263         kmem_cache_destroy(btrfs_ordered_extent_cache);
1264 }