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 *ordered_tree_search(struct btrfs_inode *inode,
 128                                                   u64 file_offset)
 129 {
 130         struct rb_node *prev = NULL;
 131         struct rb_node *ret;
 132         struct btrfs_ordered_extent *entry;
 133
 134         if (inode->ordered_tree_last) {
 135                 entry = rb_entry(inode->ordered_tree_last, struct btrfs_ordered_extent,
 136                                  rb_node);
 137                 if (in_range(file_offset, entry->file_offset, entry->num_bytes))
 138                         return inode->ordered_tree_last;
 139         }
 140         ret = __tree_search(&inode->ordered_tree, file_offset, &prev);
 141         if (!ret)
 142                 ret = prev;
 143         if (ret)
 144                 inode->ordered_tree_last = ret;
 145         return ret;
 146 }
 147
 148 static struct btrfs_ordered_extent *alloc_ordered_extent(
 149                         struct btrfs_inode *inode, u64 file_offset, u64 num_bytes,
 150                         u64 ram_bytes, u64 disk_bytenr, u64 disk_num_bytes,
 151                         u64 offset, unsigned long flags, int compress_type)
 152 {
 153         struct btrfs_ordered_extent *entry;
 154         int ret;
 155         u64 qgroup_rsv = 0;
 156
 157         if (flags &
 158             ((1 << BTRFS_ORDERED_NOCOW) | (1 << BTRFS_ORDERED_PREALLOC))) {
 159                 /* For nocow write, we can release the qgroup rsv right now */
 160                 ret = btrfs_qgroup_free_data(inode, NULL, file_offset, num_bytes, &qgroup_rsv);
 161                 if (ret < 0)
 162                         return ERR_PTR(ret);
 163         } else {
 164                 /*
 165                  * The ordered extent has reserved qgroup space, release now
 166                  * and pass the reserved number for qgroup_record to free.
 167                  */
 168                 ret = btrfs_qgroup_release_data(inode, file_offset, num_bytes, &qgroup_rsv);
 169                 if (ret < 0)
 170                         return ERR_PTR(ret);
 171         }
 172         entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 173         if (!entry)
 174                 return ERR_PTR(-ENOMEM);
 175
 176         entry->file_offset = file_offset;
 177         entry->num_bytes = num_bytes;
 178         entry->ram_bytes = ram_bytes;
 179         entry->disk_bytenr = disk_bytenr;
 180         entry->disk_num_bytes = disk_num_bytes;
 181         entry->offset = offset;
 182         entry->bytes_left = num_bytes;
 183         entry->inode = igrab(&inode->vfs_inode);
 184         entry->compress_type = compress_type;
 185         entry->truncated_len = (u64)-1;
 186         entry->qgroup_rsv = qgroup_rsv;
 187         entry->flags = flags;
 188         refcount_set(&entry->refs, 1);
 189         init_waitqueue_head(&entry->wait);
 190         INIT_LIST_HEAD(&entry->list);
 191         INIT_LIST_HEAD(&entry->log_list);
 192         INIT_LIST_HEAD(&entry->root_extent_list);
 193         INIT_LIST_HEAD(&entry->work_list);
 194         INIT_LIST_HEAD(&entry->bioc_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_root *root = inode->root;
 213         struct btrfs_fs_info *fs_info = root->fs_info;
 214         struct rb_node *node;
 215
 216         trace_btrfs_ordered_extent_add(inode, entry);
 217
 218         percpu_counter_add_batch(&fs_info->ordered_bytes, entry->num_bytes,
 219                                  fs_info->delalloc_batch);
 220
 221         /* One ref for the tree. */
 222         refcount_inc(&entry->refs);
 223
 224         spin_lock_irq(&inode->ordered_tree_lock);
 225         node = tree_insert(&inode->ordered_tree, entry->file_offset,
 226                            &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(&inode->ordered_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_inode *inode = BTRFS_I(entry->inode);
 292
 293         spin_lock_irq(&inode->ordered_tree_lock);
 294         list_add_tail(&sum->list, &entry->list);
 295         spin_unlock_irq(&inode->ordered_tree_lock);
 296 }
 297
 298 static void finish_ordered_fn(struct btrfs_work *work)
 299 {
 300         struct btrfs_ordered_extent *ordered_extent;
 301
 302         ordered_extent = container_of(work, struct btrfs_ordered_extent, work);
 303         btrfs_finish_ordered_io(ordered_extent);
 304 }
 305
 306 static bool can_finish_ordered_extent(struct btrfs_ordered_extent *ordered,
 307                                       struct page *page, u64 file_offset,
 308                                       u64 len, bool uptodate)
 309 {
 310         struct btrfs_inode *inode = BTRFS_I(ordered->inode);
 311         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 312
 313         lockdep_assert_held(&inode->ordered_tree_lock);
 314
 315         if (page) {
 316                 ASSERT(page->mapping);
 317                 ASSERT(page_offset(page) <= file_offset);
 318                 ASSERT(file_offset + len <= page_offset(page) + PAGE_SIZE);
 319
 320                 /*
 321                  * Ordered (Private2) bit indicates whether we still have
 322                  * pending io unfinished for the ordered extent.
 323                  *
 324                  * If there's no such bit, we need to skip to next range.
 325                  */
 326                 if (!btrfs_folio_test_ordered(fs_info, page_folio(page),
 327                                               file_offset, len))
 328                         return false;
 329                 btrfs_folio_clear_ordered(fs_info, page_folio(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);
 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 rb_node *node;
 409         struct btrfs_ordered_extent *entry = NULL;
 410         unsigned long flags;
 411         u64 cur = file_offset;
 412
 413         trace_btrfs_writepage_end_io_hook(inode, file_offset,
 414                                           file_offset + num_bytes - 1,
 415                                           uptodate);
 416
 417         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 418         while (cur < file_offset + num_bytes) {
 419                 u64 entry_end;
 420                 u64 end;
 421                 u32 len;
 422
 423                 node = ordered_tree_search(inode, cur);
 424                 /* No ordered extents at all */
 425                 if (!node)
 426                         break;
 427
 428                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 429                 entry_end = entry->file_offset + entry->num_bytes;
 430                 /*
 431                  * |<-- OE --->|  |
 432                  *                cur
 433                  * Go to next OE.
 434                  */
 435                 if (cur >= entry_end) {
 436                         node = rb_next(node);
 437                         /* No more ordered extents, exit */
 438                         if (!node)
 439                                 break;
 440                         entry = rb_entry(node, struct btrfs_ordered_extent,
 441                                          rb_node);
 442
 443                         /* Go to next ordered extent and continue */
 444                         cur = entry->file_offset;
 445                         continue;
 446                 }
 447                 /*
 448                  * |    |<--- OE --->|
 449                  * cur
 450                  * Go to the start of OE.
 451                  */
 452                 if (cur < entry->file_offset) {
 453                         cur = entry->file_offset;
 454                         continue;
 455                 }
 456
 457                 /*
 458                  * Now we are definitely inside one ordered extent.
 459                  *
 460                  * |<--- OE --->|
 461                  *      |
 462                  *      cur
 463                  */
 464                 end = min(entry->file_offset + entry->num_bytes,
 465                           file_offset + num_bytes) - 1;
 466                 ASSERT(end + 1 - cur < U32_MAX);
 467                 len = end + 1 - cur;
 468
 469                 if (can_finish_ordered_extent(entry, page, cur, len, uptodate)) {
 470                         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 471                         btrfs_queue_ordered_fn(entry);
 472                         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 473                 }
 474                 cur += len;
 475         }
 476         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 477 }
 478
 479 /*
 480  * Finish IO for one ordered extent across a given range.  The range can only
 481  * contain one ordered extent.
 482  *
 483  * @cached:      The cached ordered extent. If not NULL, we can skip the tree
 484  *               search and use the ordered extent directly.
 485  *               Will be also used to store the finished ordered extent.
 486  * @file_offset: File offset for the finished IO
 487  * @io_size:     Length of the finish IO range
 488  *
 489  * Return true if the ordered extent is finished in the range, and update
 490  * @cached.
 491  * Return false otherwise.
 492  *
 493  * NOTE: The range can NOT cross multiple ordered extents.
 494  * Thus caller should ensure the range doesn't cross ordered extents.
 495  */
 496 bool btrfs_dec_test_ordered_pending(struct btrfs_inode *inode,
 497                                     struct btrfs_ordered_extent **cached,
 498                                     u64 file_offset, u64 io_size)
 499 {
 500         struct rb_node *node;
 501         struct btrfs_ordered_extent *entry = NULL;
 502         unsigned long flags;
 503         bool finished = false;
 504
 505         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 506         if (cached && *cached) {
 507                 entry = *cached;
 508                 goto have_entry;
 509         }
 510
 511         node = ordered_tree_search(inode, file_offset);
 512         if (!node)
 513                 goto out;
 514
 515         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 516 have_entry:
 517         if (!in_range(file_offset, entry->file_offset, entry->num_bytes))
 518                 goto out;
 519
 520         if (io_size > entry->bytes_left)
 521                 btrfs_crit(inode->root->fs_info,
 522                            "bad ordered accounting left %llu size %llu",
 523                        entry->bytes_left, io_size);
 524
 525         entry->bytes_left -= io_size;
 526
 527         if (entry->bytes_left == 0) {
 528                 /*
 529                  * Ensure only one caller can set the flag and finished_ret
 530                  * accordingly
 531                  */
 532                 finished = !test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 533                 /* test_and_set_bit implies a barrier */
 534                 cond_wake_up_nomb(&entry->wait);
 535         }
 536 out:
 537         if (finished && cached && entry) {
 538                 *cached = entry;
 539                 refcount_inc(&entry->refs);
 540                 trace_btrfs_ordered_extent_dec_test_pending(inode, entry);
 541         }
 542         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 543         return finished;
 544 }
 545
 546 /*
 547  * used to drop a reference on an ordered extent.  This will free
 548  * the extent if the last reference is dropped
 549  */
 550 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 551 {
 552         struct list_head *cur;
 553         struct btrfs_ordered_sum *sum;
 554
 555         trace_btrfs_ordered_extent_put(BTRFS_I(entry->inode), entry);
 556
 557         if (refcount_dec_and_test(&entry->refs)) {
 558                 ASSERT(list_empty(&entry->root_extent_list));
 559                 ASSERT(list_empty(&entry->log_list));
 560                 ASSERT(RB_EMPTY_NODE(&entry->rb_node));
 561                 if (entry->inode)
 562                         btrfs_add_delayed_iput(BTRFS_I(entry->inode));
 563                 while (!list_empty(&entry->list)) {
 564                         cur = entry->list.next;
 565                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 566                         list_del(&sum->list);
 567                         kvfree(sum);
 568                 }
 569                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
 570         }
 571 }
 572
 573 /*
 574  * remove an ordered extent from the tree.  No references are dropped
 575  * and waiters are woken up.
 576  */
 577 void btrfs_remove_ordered_extent(struct btrfs_inode *btrfs_inode,
 578                                  struct btrfs_ordered_extent *entry)
 579 {
 580         struct btrfs_root *root = btrfs_inode->root;
 581         struct btrfs_fs_info *fs_info = root->fs_info;
 582         struct rb_node *node;
 583         bool pending;
 584         bool freespace_inode;
 585
 586         /*
 587          * If this is a free space inode the thread has not acquired the ordered
 588          * extents lockdep map.
 589          */
 590         freespace_inode = btrfs_is_free_space_inode(btrfs_inode);
 591
 592         btrfs_lockdep_acquire(fs_info, btrfs_trans_pending_ordered);
 593         /* This is paired with btrfs_alloc_ordered_extent. */
 594         spin_lock(&btrfs_inode->lock);
 595         btrfs_mod_outstanding_extents(btrfs_inode, -1);
 596         spin_unlock(&btrfs_inode->lock);
 597         if (root != fs_info->tree_root) {
 598                 u64 release;
 599
 600                 if (test_bit(BTRFS_ORDERED_ENCODED, &entry->flags))
 601                         release = entry->disk_num_bytes;
 602                 else
 603                         release = entry->num_bytes;
 604                 btrfs_delalloc_release_metadata(btrfs_inode, release,
 605                                                 test_bit(BTRFS_ORDERED_IOERR,
 606                                                          &entry->flags));
 607         }
 608
 609         percpu_counter_add_batch(&fs_info->ordered_bytes, -entry->num_bytes,
 610                                  fs_info->delalloc_batch);
 611
 612         spin_lock_irq(&btrfs_inode->ordered_tree_lock);
 613         node = &entry->rb_node;
 614         rb_erase(node, &btrfs_inode->ordered_tree);
 615         RB_CLEAR_NODE(node);
 616         if (btrfs_inode->ordered_tree_last == node)
 617                 btrfs_inode->ordered_tree_last = NULL;
 618         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 619         pending = test_and_clear_bit(BTRFS_ORDERED_PENDING, &entry->flags);
 620         spin_unlock_irq(&btrfs_inode->ordered_tree_lock);
 621
 622         /*
 623          * The current running transaction is waiting on us, we need to let it
 624          * know that we're complete and wake it up.
 625          */
 626         if (pending) {
 627                 struct btrfs_transaction *trans;
 628
 629                 /*
 630                  * The checks for trans are just a formality, it should be set,
 631                  * but if it isn't we don't want to deref/assert under the spin
 632                  * lock, so be nice and check if trans is set, but ASSERT() so
 633                  * if it isn't set a developer will notice.
 634                  */
 635                 spin_lock(&fs_info->trans_lock);
 636                 trans = fs_info->running_transaction;
 637                 if (trans)
 638                         refcount_inc(&trans->use_count);
 639                 spin_unlock(&fs_info->trans_lock);
 640
 641                 ASSERT(trans || BTRFS_FS_ERROR(fs_info));
 642                 if (trans) {
 643                         if (atomic_dec_and_test(&trans->pending_ordered))
 644                                 wake_up(&trans->pending_wait);
 645                         btrfs_put_transaction(trans);
 646                 }
 647         }
 648
 649         btrfs_lockdep_release(fs_info, btrfs_trans_pending_ordered);
 650
 651         spin_lock(&root->ordered_extent_lock);
 652         list_del_init(&entry->root_extent_list);
 653         root->nr_ordered_extents--;
 654
 655         trace_btrfs_ordered_extent_remove(btrfs_inode, entry);
 656
 657         if (!root->nr_ordered_extents) {
 658                 spin_lock(&fs_info->ordered_root_lock);
 659                 BUG_ON(list_empty(&root->ordered_root));
 660                 list_del_init(&root->ordered_root);
 661                 spin_unlock(&fs_info->ordered_root_lock);
 662         }
 663         spin_unlock(&root->ordered_extent_lock);
 664         wake_up(&entry->wait);
 665         if (!freespace_inode)
 666                 btrfs_lockdep_release(fs_info, btrfs_ordered_extent);
 667 }
 668
 669 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 670 {
 671         struct btrfs_ordered_extent *ordered;
 672
 673         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 674         btrfs_start_ordered_extent(ordered);
 675         complete(&ordered->completion);
 676 }
 677
 678 /*
 679  * wait for all the ordered extents in a root.  This is done when balancing
 680  * space between drives.
 681  */
 682 u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
 683                                const u64 range_start, const u64 range_len)
 684 {
 685         struct btrfs_fs_info *fs_info = root->fs_info;
 686         LIST_HEAD(splice);
 687         LIST_HEAD(skipped);
 688         LIST_HEAD(works);
 689         struct btrfs_ordered_extent *ordered, *next;
 690         u64 count = 0;
 691         const u64 range_end = range_start + range_len;
 692
 693         mutex_lock(&root->ordered_extent_mutex);
 694         spin_lock(&root->ordered_extent_lock);
 695         list_splice_init(&root->ordered_extents, &splice);
 696         while (!list_empty(&splice) && nr) {
 697                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 698                                            root_extent_list);
 699
 700                 if (range_end <= ordered->disk_bytenr ||
 701                     ordered->disk_bytenr + ordered->disk_num_bytes <= range_start) {
 702                         list_move_tail(&ordered->root_extent_list, &skipped);
 703                         cond_resched_lock(&root->ordered_extent_lock);
 704                         continue;
 705                 }
 706
 707                 list_move_tail(&ordered->root_extent_list,
 708                                &root->ordered_extents);
 709                 refcount_inc(&ordered->refs);
 710                 spin_unlock(&root->ordered_extent_lock);
 711
 712                 btrfs_init_work(&ordered->flush_work,
 713                                 btrfs_run_ordered_extent_work, NULL);
 714                 list_add_tail(&ordered->work_list, &works);
 715                 btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work);
 716
 717                 cond_resched();
 718                 spin_lock(&root->ordered_extent_lock);
 719                 if (nr != U64_MAX)
 720                         nr--;
 721                 count++;
 722         }
 723         list_splice_tail(&skipped, &root->ordered_extents);
 724         list_splice_tail(&splice, &root->ordered_extents);
 725         spin_unlock(&root->ordered_extent_lock);
 726
 727         list_for_each_entry_safe(ordered, next, &works, work_list) {
 728                 list_del_init(&ordered->work_list);
 729                 wait_for_completion(&ordered->completion);
 730                 btrfs_put_ordered_extent(ordered);
 731                 cond_resched();
 732         }
 733         mutex_unlock(&root->ordered_extent_mutex);
 734
 735         return count;
 736 }
 737
 738 void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
 739                              const u64 range_start, const u64 range_len)
 740 {
 741         struct btrfs_root *root;
 742         LIST_HEAD(splice);
 743         u64 done;
 744
 745         mutex_lock(&fs_info->ordered_operations_mutex);
 746         spin_lock(&fs_info->ordered_root_lock);
 747         list_splice_init(&fs_info->ordered_roots, &splice);
 748         while (!list_empty(&splice) && nr) {
 749                 root = list_first_entry(&splice, struct btrfs_root,
 750                                         ordered_root);
 751                 root = btrfs_grab_root(root);
 752                 BUG_ON(!root);
 753                 list_move_tail(&root->ordered_root,
 754                                &fs_info->ordered_roots);
 755                 spin_unlock(&fs_info->ordered_root_lock);
 756
 757                 done = btrfs_wait_ordered_extents(root, nr,
 758                                                   range_start, range_len);
 759                 btrfs_put_root(root);
 760
 761                 spin_lock(&fs_info->ordered_root_lock);
 762                 if (nr != U64_MAX) {
 763                         nr -= done;
 764                 }
 765         }
 766         list_splice_tail(&splice, &fs_info->ordered_roots);
 767         spin_unlock(&fs_info->ordered_root_lock);
 768         mutex_unlock(&fs_info->ordered_operations_mutex);
 769 }
 770
 771 /*
 772  * Start IO and wait for a given ordered extent to finish.
 773  *
 774  * Wait on page writeback for all the pages in the extent and the IO completion
 775  * code to insert metadata into the btree corresponding to the extent.
 776  */
 777 void btrfs_start_ordered_extent(struct btrfs_ordered_extent *entry)
 778 {
 779         u64 start = entry->file_offset;
 780         u64 end = start + entry->num_bytes - 1;
 781         struct btrfs_inode *inode = BTRFS_I(entry->inode);
 782         bool freespace_inode;
 783
 784         trace_btrfs_ordered_extent_start(inode, entry);
 785
 786         /*
 787          * If this is a free space inode do not take the ordered extents lockdep
 788          * map.
 789          */
 790         freespace_inode = btrfs_is_free_space_inode(inode);
 791
 792         /*
 793          * pages in the range can be dirty, clean or writeback.  We
 794          * start IO on any dirty ones so the wait doesn't stall waiting
 795          * for the flusher thread to find them
 796          */
 797         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 798                 filemap_fdatawrite_range(inode->vfs_inode.i_mapping, start, end);
 799
 800         if (!freespace_inode)
 801                 btrfs_might_wait_for_event(inode->root->fs_info, btrfs_ordered_extent);
 802         wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE, &entry->flags));
 803 }
 804
 805 /*
 806  * Used to wait on ordered extents across a large range of bytes.
 807  */
 808 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 809 {
 810         int ret = 0;
 811         int ret_wb = 0;
 812         u64 end;
 813         u64 orig_end;
 814         struct btrfs_ordered_extent *ordered;
 815
 816         if (start + len < start) {
 817                 orig_end = OFFSET_MAX;
 818         } else {
 819                 orig_end = start + len - 1;
 820                 if (orig_end > OFFSET_MAX)
 821                         orig_end = OFFSET_MAX;
 822         }
 823
 824         /* start IO across the range first to instantiate any delalloc
 825          * extents
 826          */
 827         ret = btrfs_fdatawrite_range(inode, start, orig_end);
 828         if (ret)
 829                 return ret;
 830
 831         /*
 832          * If we have a writeback error don't return immediately. Wait first
 833          * for any ordered extents that haven't completed yet. This is to make
 834          * sure no one can dirty the same page ranges and call writepages()
 835          * before the ordered extents complete - to avoid failures (-EEXIST)
 836          * when adding the new ordered extents to the ordered tree.
 837          */
 838         ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 839
 840         end = orig_end;
 841         while (1) {
 842                 ordered = btrfs_lookup_first_ordered_extent(BTRFS_I(inode), end);
 843                 if (!ordered)
 844                         break;
 845                 if (ordered->file_offset > orig_end) {
 846                         btrfs_put_ordered_extent(ordered);
 847                         break;
 848                 }
 849                 if (ordered->file_offset + ordered->num_bytes <= start) {
 850                         btrfs_put_ordered_extent(ordered);
 851                         break;
 852                 }
 853                 btrfs_start_ordered_extent(ordered);
 854                 end = ordered->file_offset;
 855                 /*
 856                  * If the ordered extent had an error save the error but don't
 857                  * exit without waiting first for all other ordered extents in
 858                  * the range to complete.
 859                  */
 860                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 861                         ret = -EIO;
 862                 btrfs_put_ordered_extent(ordered);
 863                 if (end == 0 || end == start)
 864                         break;
 865                 end--;
 866         }
 867         return ret_wb ? ret_wb : ret;
 868 }
 869
 870 /*
 871  * find an ordered extent corresponding to file_offset.  return NULL if
 872  * nothing is found, otherwise take a reference on the extent and return it
 873  */
 874 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct btrfs_inode *inode,
 875                                                          u64 file_offset)
 876 {
 877         struct rb_node *node;
 878         struct btrfs_ordered_extent *entry = NULL;
 879         unsigned long flags;
 880
 881         spin_lock_irqsave(&inode->ordered_tree_lock, flags);
 882         node = ordered_tree_search(inode, file_offset);
 883         if (!node)
 884                 goto out;
 885
 886         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 887         if (!in_range(file_offset, entry->file_offset, entry->num_bytes))
 888                 entry = NULL;
 889         if (entry) {
 890                 refcount_inc(&entry->refs);
 891                 trace_btrfs_ordered_extent_lookup(inode, entry);
 892         }
 893 out:
 894         spin_unlock_irqrestore(&inode->ordered_tree_lock, flags);
 895         return entry;
 896 }
 897
 898 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 899  * extents that exist in the range, rather than just the start of the range.
 900  */
 901 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
 902                 struct btrfs_inode *inode, u64 file_offset, u64 len)
 903 {
 904         struct rb_node *node;
 905         struct btrfs_ordered_extent *entry = NULL;
 906
 907         spin_lock_irq(&inode->ordered_tree_lock);
 908         node = ordered_tree_search(inode, file_offset);
 909         if (!node) {
 910                 node = ordered_tree_search(inode, file_offset + len);
 911                 if (!node)
 912                         goto out;
 913         }
 914
 915         while (1) {
 916                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 917                 if (range_overlaps(entry, file_offset, len))
 918                         break;
 919
 920                 if (entry->file_offset >= file_offset + len) {
 921                         entry = NULL;
 922                         break;
 923                 }
 924                 entry = NULL;
 925                 node = rb_next(node);
 926                 if (!node)
 927                         break;
 928         }
 929 out:
 930         if (entry) {
 931                 refcount_inc(&entry->refs);
 932                 trace_btrfs_ordered_extent_lookup_range(inode, entry);
 933         }
 934         spin_unlock_irq(&inode->ordered_tree_lock);
 935         return entry;
 936 }
 937
 938 /*
 939  * Adds all ordered extents to the given list. The list ends up sorted by the
 940  * file_offset of the ordered extents.
 941  */
 942 void btrfs_get_ordered_extents_for_logging(struct btrfs_inode *inode,
 943                                            struct list_head *list)
 944 {
 945         struct rb_node *n;
 946
 947         ASSERT(inode_is_locked(&inode->vfs_inode));
 948
 949         spin_lock_irq(&inode->ordered_tree_lock);
 950         for (n = rb_first(&inode->ordered_tree); n; n = rb_next(n)) {
 951                 struct btrfs_ordered_extent *ordered;
 952
 953                 ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
 954
 955                 if (test_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
 956                         continue;
 957
 958                 ASSERT(list_empty(&ordered->log_list));
 959                 list_add_tail(&ordered->log_list, list);
 960                 refcount_inc(&ordered->refs);
 961                 trace_btrfs_ordered_extent_lookup_for_logging(inode, ordered);
 962         }
 963         spin_unlock_irq(&inode->ordered_tree_lock);
 964 }
 965
 966 /*
 967  * lookup and return any extent before 'file_offset'.  NULL is returned
 968  * if none is found
 969  */
 970 struct btrfs_ordered_extent *
 971 btrfs_lookup_first_ordered_extent(struct btrfs_inode *inode, u64 file_offset)
 972 {
 973         struct rb_node *node;
 974         struct btrfs_ordered_extent *entry = NULL;
 975
 976         spin_lock_irq(&inode->ordered_tree_lock);
 977         node = ordered_tree_search(inode, file_offset);
 978         if (!node)
 979                 goto out;
 980
 981         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 982         refcount_inc(&entry->refs);
 983         trace_btrfs_ordered_extent_lookup_first(inode, entry);
 984 out:
 985         spin_unlock_irq(&inode->ordered_tree_lock);
 986         return entry;
 987 }
 988
 989 /*
 990  * Lookup the first ordered extent that overlaps the range
 991  * [@file_offset, @file_offset + @len).
 992  *
 993  * The difference between this and btrfs_lookup_first_ordered_extent() is
 994  * that this one won't return any ordered extent that does not overlap the range.
 995  * And the difference against btrfs_lookup_ordered_extent() is, this function
 996  * ensures the first ordered extent gets returned.
 997  */
 998 struct btrfs_ordered_extent *btrfs_lookup_first_ordered_range(
 999                         struct btrfs_inode *inode, u64 file_offset, u64 len)
1000 {
1001         struct rb_node *node;
1002         struct rb_node *cur;
1003         struct rb_node *prev;
1004         struct rb_node *next;
1005         struct btrfs_ordered_extent *entry = NULL;
1006
1007         spin_lock_irq(&inode->ordered_tree_lock);
1008         node = inode->ordered_tree.rb_node;
1009         /*
1010          * Here we don't want to use tree_search() which will use tree->last
1011          * and screw up the search order.
1012          * And __tree_search() can't return the adjacent ordered extents
1013          * either, thus here we do our own search.
1014          */
1015         while (node) {
1016                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
1017
1018                 if (file_offset < entry->file_offset) {
1019                         node = node->rb_left;
1020                 } else if (file_offset >= entry_end(entry)) {
1021                         node = node->rb_right;
1022                 } else {
1023                         /*
1024                          * Direct hit, got an ordered extent that starts at
1025                          * @file_offset
1026                          */
1027                         goto out;
1028                 }
1029         }
1030         if (!entry) {
1031                 /* Empty tree */
1032                 goto out;
1033         }
1034
1035         cur = &entry->rb_node;
1036         /* We got an entry around @file_offset, check adjacent entries */
1037         if (entry->file_offset < file_offset) {
1038                 prev = cur;
1039                 next = rb_next(cur);
1040         } else {
1041                 prev = rb_prev(cur);
1042                 next = cur;
1043         }
1044         if (prev) {
1045                 entry = rb_entry(prev, struct btrfs_ordered_extent, rb_node);
1046                 if (range_overlaps(entry, file_offset, len))
1047                         goto out;
1048         }
1049         if (next) {
1050                 entry = rb_entry(next, struct btrfs_ordered_extent, rb_node);
1051                 if (range_overlaps(entry, file_offset, len))
1052                         goto out;
1053         }
1054         /* No ordered extent in the range */
1055         entry = NULL;
1056 out:
1057         if (entry) {
1058                 refcount_inc(&entry->refs);
1059                 trace_btrfs_ordered_extent_lookup_first_range(inode, entry);
1060         }
1061
1062         spin_unlock_irq(&inode->ordered_tree_lock);
1063         return entry;
1064 }
1065
1066 /*
1067  * Lock the passed range and ensures all pending ordered extents in it are run
1068  * to completion.
1069  *
1070  * @inode:        Inode whose ordered tree is to be searched
1071  * @start:        Beginning of range to flush
1072  * @end:          Last byte of range to lock
1073  * @cached_state: If passed, will return the extent state responsible for the
1074  *                locked range. It's the caller's responsibility to free the
1075  *                cached state.
1076  *
1077  * Always return with the given range locked, ensuring after it's called no
1078  * order extent can be pending.
1079  */
1080 void btrfs_lock_and_flush_ordered_range(struct btrfs_inode *inode, u64 start,
1081                                         u64 end,
1082                                         struct extent_state **cached_state)
1083 {
1084         struct btrfs_ordered_extent *ordered;
1085         struct extent_state *cache = NULL;
1086         struct extent_state **cachedp = &cache;
1087
1088         if (cached_state)
1089                 cachedp = cached_state;
1090
1091         while (1) {
1092                 lock_extent(&inode->io_tree, start, end, cachedp);
1093                 ordered = btrfs_lookup_ordered_range(inode, start,
1094                                                      end - start + 1);
1095                 if (!ordered) {
1096                         /*
1097                          * If no external cached_state has been passed then
1098                          * decrement the extra ref taken for cachedp since we
1099                          * aren't exposing it outside of this function
1100                          */
1101                         if (!cached_state)
1102                                 refcount_dec(&cache->refs);
1103                         break;
1104                 }
1105                 unlock_extent(&inode->io_tree, start, end, cachedp);
1106                 btrfs_start_ordered_extent(ordered);
1107                 btrfs_put_ordered_extent(ordered);
1108         }
1109 }
1110
1111 /*
1112  * Lock the passed range and ensure all pending ordered extents in it are run
1113  * to completion in nowait mode.
1114  *
1115  * Return true if btrfs_lock_ordered_range does not return any extents,
1116  * otherwise false.
1117  */
1118 bool btrfs_try_lock_ordered_range(struct btrfs_inode *inode, u64 start, u64 end,
1119                                   struct extent_state **cached_state)
1120 {
1121         struct btrfs_ordered_extent *ordered;
1122
1123         if (!try_lock_extent(&inode->io_tree, start, end, cached_state))
1124                 return false;
1125
1126         ordered = btrfs_lookup_ordered_range(inode, start, end - start + 1);
1127         if (!ordered)
1128                 return true;
1129
1130         btrfs_put_ordered_extent(ordered);
1131         unlock_extent(&inode->io_tree, start, end, cached_state);
1132
1133         return false;
1134 }
1135
1136 /* Split out a new ordered extent for this first @len bytes of @ordered. */
1137 struct btrfs_ordered_extent *btrfs_split_ordered_extent(
1138                         struct btrfs_ordered_extent *ordered, u64 len)
1139 {
1140         struct btrfs_inode *inode = BTRFS_I(ordered->inode);
1141         struct btrfs_root *root = inode->root;
1142         struct btrfs_fs_info *fs_info = root->fs_info;
1143         u64 file_offset = ordered->file_offset;
1144         u64 disk_bytenr = ordered->disk_bytenr;
1145         unsigned long flags = ordered->flags;
1146         struct btrfs_ordered_sum *sum, *tmpsum;
1147         struct btrfs_ordered_extent *new;
1148         struct rb_node *node;
1149         u64 offset = 0;
1150
1151         trace_btrfs_ordered_extent_split(inode, ordered);
1152
1153         ASSERT(!(flags & (1U << BTRFS_ORDERED_COMPRESSED)));
1154
1155         /*
1156          * The entire bio must be covered by the ordered extent, but we can't
1157          * reduce the original extent to a zero length either.
1158          */
1159         if (WARN_ON_ONCE(len >= ordered->num_bytes))
1160                 return ERR_PTR(-EINVAL);
1161         /* We cannot split partially completed ordered extents. */
1162         if (ordered->bytes_left) {
1163                 ASSERT(!(flags & ~BTRFS_ORDERED_TYPE_FLAGS));
1164                 if (WARN_ON_ONCE(ordered->bytes_left != ordered->disk_num_bytes))
1165                         return ERR_PTR(-EINVAL);
1166         }
1167         /* We cannot split a compressed ordered extent. */
1168         if (WARN_ON_ONCE(ordered->disk_num_bytes != ordered->num_bytes))
1169                 return ERR_PTR(-EINVAL);
1170
1171         new = alloc_ordered_extent(inode, file_offset, len, len, disk_bytenr,
1172                                    len, 0, flags, ordered->compress_type);
1173         if (IS_ERR(new))
1174                 return new;
1175
1176         /* One ref for the tree. */
1177         refcount_inc(&new->refs);
1178
1179         spin_lock_irq(&root->ordered_extent_lock);
1180         spin_lock(&inode->ordered_tree_lock);
1181         /* Remove from tree once */
1182         node = &ordered->rb_node;
1183         rb_erase(node, &inode->ordered_tree);
1184         RB_CLEAR_NODE(node);
1185         if (inode->ordered_tree_last == node)
1186                 inode->ordered_tree_last = NULL;
1187
1188         ordered->file_offset += len;
1189         ordered->disk_bytenr += len;
1190         ordered->num_bytes -= len;
1191         ordered->disk_num_bytes -= len;
1192
1193         if (test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags)) {
1194                 ASSERT(ordered->bytes_left == 0);
1195                 new->bytes_left = 0;
1196         } else {
1197                 ordered->bytes_left -= len;
1198         }
1199
1200         if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags)) {
1201                 if (ordered->truncated_len > len) {
1202                         ordered->truncated_len -= len;
1203                 } else {
1204                         new->truncated_len = ordered->truncated_len;
1205                         ordered->truncated_len = 0;
1206                 }
1207         }
1208
1209         list_for_each_entry_safe(sum, tmpsum, &ordered->list, list) {
1210                 if (offset == len)
1211                         break;
1212                 list_move_tail(&sum->list, &new->list);
1213                 offset += sum->len;
1214         }
1215
1216         /* Re-insert the node */
1217         node = tree_insert(&inode->ordered_tree, ordered->file_offset,
1218                            &ordered->rb_node);
1219         if (node)
1220                 btrfs_panic(fs_info, -EEXIST,
1221                         "zoned: inconsistency in ordered tree at offset %llu",
1222                         ordered->file_offset);
1223
1224         node = tree_insert(&inode->ordered_tree, new->file_offset, &new->rb_node);
1225         if (node)
1226                 btrfs_panic(fs_info, -EEXIST,
1227                         "zoned: inconsistency in ordered tree at offset %llu",
1228                         new->file_offset);
1229         spin_unlock(&inode->ordered_tree_lock);
1230
1231         list_add_tail(&new->root_extent_list, &root->ordered_extents);
1232         root->nr_ordered_extents++;
1233         spin_unlock_irq(&root->ordered_extent_lock);
1234         return new;
1235 }
1236
1237 int __init ordered_data_init(void)
1238 {
1239         btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
1240                                      sizeof(struct btrfs_ordered_extent), 0,
1241                                      SLAB_MEM_SPREAD,
1242                                      NULL);
1243         if (!btrfs_ordered_extent_cache)
1244                 return -ENOMEM;
1245
1246         return 0;
1247 }
1248
1249 void __cold ordered_data_exit(void)
1250 {
1251         kmem_cache_destroy(btrfs_ordered_extent_cache);
1252 }