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 "misc.h"
  11 #include "ctree.h"
  12 #include "transaction.h"
  13 #include "btrfs_inode.h"
  14 #include "extent_io.h"
  15 #include "disk-io.h"
  16 #include "compression.h"
  17 #include "delalloc-space.h"
  18 #include "qgroup.h"
  19
  20 static struct kmem_cache *btrfs_ordered_extent_cache;
  21
  22 static u64 entry_end(struct btrfs_ordered_extent *entry)
  23 {
  24         if (entry->file_offset + entry->num_bytes < entry->file_offset)
  25                 return (u64)-1;
  26         return entry->file_offset + entry->num_bytes;
  27 }
  28
  29 /* returns NULL if the insertion worked, or it returns the node it did find
  30  * in the tree
  31  */
  32 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  33                                    struct rb_node *node)
  34 {
  35         struct rb_node **p = &root->rb_node;
  36         struct rb_node *parent = NULL;
  37         struct btrfs_ordered_extent *entry;
  38
  39         while (*p) {
  40                 parent = *p;
  41                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  42
  43                 if (file_offset < entry->file_offset)
  44                         p = &(*p)->rb_left;
  45                 else if (file_offset >= entry_end(entry))
  46                         p = &(*p)->rb_right;
  47                 else
  48                         return parent;
  49         }
  50
  51         rb_link_node(node, parent, p);
  52         rb_insert_color(node, root);
  53         return NULL;
  54 }
  55
  56 /*
  57  * look for a given offset in the tree, and if it can't be found return the
  58  * first lesser offset
  59  */
  60 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  61                                      struct rb_node **prev_ret)
  62 {
  63         struct rb_node *n = root->rb_node;
  64         struct rb_node *prev = NULL;
  65         struct rb_node *test;
  66         struct btrfs_ordered_extent *entry;
  67         struct btrfs_ordered_extent *prev_entry = NULL;
  68
  69         while (n) {
  70                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  71                 prev = n;
  72                 prev_entry = entry;
  73
  74                 if (file_offset < entry->file_offset)
  75                         n = n->rb_left;
  76                 else if (file_offset >= entry_end(entry))
  77                         n = n->rb_right;
  78                 else
  79                         return n;
  80         }
  81         if (!prev_ret)
  82                 return NULL;
  83
  84         while (prev && file_offset >= entry_end(prev_entry)) {
  85                 test = rb_next(prev);
  86                 if (!test)
  87                         break;
  88                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
  89                                       rb_node);
  90                 if (file_offset < entry_end(prev_entry))
  91                         break;
  92
  93                 prev = test;
  94         }
  95         if (prev)
  96                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
  97                                       rb_node);
  98         while (prev && file_offset < entry_end(prev_entry)) {
  99                 test = rb_prev(prev);
 100                 if (!test)
 101                         break;
 102                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 103                                       rb_node);
 104                 prev = test;
 105         }
 106         *prev_ret = prev;
 107         return NULL;
 108 }
 109
 110 /*
 111  * helper to check if a given offset is inside a given entry
 112  */
 113 static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
 114 {
 115         if (file_offset < entry->file_offset ||
 116             entry->file_offset + entry->num_bytes <= file_offset)
 117                 return 0;
 118         return 1;
 119 }
 120
 121 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 122                           u64 len)
 123 {
 124         if (file_offset + len <= entry->file_offset ||
 125             entry->file_offset + entry->num_bytes <= file_offset)
 126                 return 0;
 127         return 1;
 128 }
 129
 130 /*
 131  * look find the first ordered struct that has this offset, otherwise
 132  * the first one less than this offset
 133  */
 134 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 135                                           u64 file_offset)
 136 {
 137         struct rb_root *root = &tree->tree;
 138         struct rb_node *prev = NULL;
 139         struct rb_node *ret;
 140         struct btrfs_ordered_extent *entry;
 141
 142         if (tree->last) {
 143                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 144                                  rb_node);
 145                 if (offset_in_entry(entry, file_offset))
 146                         return tree->last;
 147         }
 148         ret = __tree_search(root, file_offset, &prev);
 149         if (!ret)
 150                 ret = prev;
 151         if (ret)
 152                 tree->last = ret;
 153         return ret;
 154 }
 155
 156 /*
 157  * Allocate and add a new ordered_extent into the per-inode tree.
 158  *
 159  * The tree is given a single reference on the ordered extent that was
 160  * inserted.
 161  */
 162 static int __btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset,
 163                                       u64 disk_bytenr, u64 num_bytes,
 164                                       u64 disk_num_bytes, int type, int dio,
 165                                       int compress_type)
 166 {
 167         struct btrfs_root *root = inode->root;
 168         struct btrfs_fs_info *fs_info = root->fs_info;
 169         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 170         struct rb_node *node;
 171         struct btrfs_ordered_extent *entry;
 172         int ret;
 173
 174         if (type == BTRFS_ORDERED_NOCOW || type == BTRFS_ORDERED_PREALLOC) {
 175                 /* For nocow write, we can release the qgroup rsv right now */
 176                 ret = btrfs_qgroup_free_data(inode, NULL, file_offset, num_bytes);
 177                 if (ret < 0)
 178                         return ret;
 179                 ret = 0;
 180         } else {
 181                 /*
 182                  * The ordered extent has reserved qgroup space, release now
 183                  * and pass the reserved number for qgroup_record to free.
 184                  */
 185                 ret = btrfs_qgroup_release_data(inode, file_offset, num_bytes);
 186                 if (ret < 0)
 187                         return ret;
 188         }
 189         entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 190         if (!entry)
 191                 return -ENOMEM;
 192
 193         entry->file_offset = file_offset;
 194         entry->disk_bytenr = disk_bytenr;
 195         entry->num_bytes = num_bytes;
 196         entry->disk_num_bytes = disk_num_bytes;
 197         entry->bytes_left = num_bytes;
 198         entry->inode = igrab(&inode->vfs_inode);
 199         entry->compress_type = compress_type;
 200         entry->truncated_len = (u64)-1;
 201         entry->qgroup_rsv = ret;
 202         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 203                 set_bit(type, &entry->flags);
 204
 205         if (dio) {
 206                 percpu_counter_add_batch(&fs_info->dio_bytes, num_bytes,
 207                                          fs_info->delalloc_batch);
 208                 set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
 209         }
 210
 211         /* one ref for the tree */
 212         refcount_set(&entry->refs, 1);
 213         init_waitqueue_head(&entry->wait);
 214         INIT_LIST_HEAD(&entry->list);
 215         INIT_LIST_HEAD(&entry->log_list);
 216         INIT_LIST_HEAD(&entry->root_extent_list);
 217         INIT_LIST_HEAD(&entry->work_list);
 218         init_completion(&entry->completion);
 219
 220         trace_btrfs_ordered_extent_add(inode, entry);
 221
 222         spin_lock_irq(&tree->lock);
 223         node = tree_insert(&tree->tree, file_offset,
 224                            &entry->rb_node);
 225         if (node)
 226                 btrfs_panic(fs_info, -EEXIST,
 227                                 "inconsistency in ordered tree at offset %llu",
 228                                 file_offset);
 229         spin_unlock_irq(&tree->lock);
 230
 231         spin_lock(&root->ordered_extent_lock);
 232         list_add_tail(&entry->root_extent_list,
 233                       &root->ordered_extents);
 234         root->nr_ordered_extents++;
 235         if (root->nr_ordered_extents == 1) {
 236                 spin_lock(&fs_info->ordered_root_lock);
 237                 BUG_ON(!list_empty(&root->ordered_root));
 238                 list_add_tail(&root->ordered_root, &fs_info->ordered_roots);
 239                 spin_unlock(&fs_info->ordered_root_lock);
 240         }
 241         spin_unlock(&root->ordered_extent_lock);
 242
 243         /*
 244          * We don't need the count_max_extents here, we can assume that all of
 245          * that work has been done at higher layers, so this is truly the
 246          * smallest the extent is going to get.
 247          */
 248         spin_lock(&inode->lock);
 249         btrfs_mod_outstanding_extents(inode, 1);
 250         spin_unlock(&inode->lock);
 251
 252         return 0;
 253 }
 254
 255 int btrfs_add_ordered_extent(struct btrfs_inode *inode, u64 file_offset,
 256                              u64 disk_bytenr, u64 num_bytes, u64 disk_num_bytes,
 257                              int type)
 258 {
 259         return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
 260                                           num_bytes, disk_num_bytes, type, 0,
 261                                           BTRFS_COMPRESS_NONE);
 262 }
 263
 264 int btrfs_add_ordered_extent_dio(struct btrfs_inode *inode, u64 file_offset,
 265                                  u64 disk_bytenr, u64 num_bytes,
 266                                  u64 disk_num_bytes, int type)
 267 {
 268         return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
 269                                           num_bytes, disk_num_bytes, type, 1,
 270                                           BTRFS_COMPRESS_NONE);
 271 }
 272
 273 int btrfs_add_ordered_extent_compress(struct btrfs_inode *inode, u64 file_offset,
 274                                       u64 disk_bytenr, u64 num_bytes,
 275                                       u64 disk_num_bytes, int type,
 276                                       int compress_type)
 277 {
 278         return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
 279                                           num_bytes, disk_num_bytes, type, 0,
 280                                           compress_type);
 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 /*
 300  * this is used to account for finished IO across a given range
 301  * of the file.  The IO may span ordered extents.  If
 302  * a given ordered_extent is completely done, 1 is returned, otherwise
 303  * 0.
 304  *
 305  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 306  * to make sure this function only returns 1 once for a given ordered extent.
 307  *
 308  * file_offset is updated to one byte past the range that is recorded as
 309  * complete.  This allows you to walk forward in the file.
 310  */
 311 int btrfs_dec_test_first_ordered_pending(struct btrfs_inode *inode,
 312                                    struct btrfs_ordered_extent **cached,
 313                                    u64 *file_offset, u64 io_size, int uptodate)
 314 {
 315         struct btrfs_fs_info *fs_info = inode->root->fs_info;
 316         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 317         struct rb_node *node;
 318         struct btrfs_ordered_extent *entry = NULL;
 319         int ret;
 320         unsigned long flags;
 321         u64 dec_end;
 322         u64 dec_start;
 323         u64 to_dec;
 324
 325         spin_lock_irqsave(&tree->lock, flags);
 326         node = tree_search(tree, *file_offset);
 327         if (!node) {
 328                 ret = 1;
 329                 goto out;
 330         }
 331
 332         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 333         if (!offset_in_entry(entry, *file_offset)) {
 334                 ret = 1;
 335                 goto out;
 336         }
 337
 338         dec_start = max(*file_offset, entry->file_offset);
 339         dec_end = min(*file_offset + io_size,
 340                       entry->file_offset + entry->num_bytes);
 341         *file_offset = dec_end;
 342         if (dec_start > dec_end) {
 343                 btrfs_crit(fs_info, "bad ordering dec_start %llu end %llu",
 344                            dec_start, dec_end);
 345         }
 346         to_dec = dec_end - dec_start;
 347         if (to_dec > entry->bytes_left) {
 348                 btrfs_crit(fs_info,
 349                            "bad ordered accounting left %llu size %llu",
 350                            entry->bytes_left, to_dec);
 351         }
 352         entry->bytes_left -= to_dec;
 353         if (!uptodate)
 354                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 355
 356         if (entry->bytes_left == 0) {
 357                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 358                 /* test_and_set_bit implies a barrier */
 359                 cond_wake_up_nomb(&entry->wait);
 360         } else {
 361                 ret = 1;
 362         }
 363 out:
 364         if (!ret && cached && entry) {
 365                 *cached = entry;
 366                 refcount_inc(&entry->refs);
 367         }
 368         spin_unlock_irqrestore(&tree->lock, flags);
 369         return ret == 0;
 370 }
 371
 372 /*
 373  * this is used to account for finished IO across a given range
 374  * of the file.  The IO should not span ordered extents.  If
 375  * a given ordered_extent is completely done, 1 is returned, otherwise
 376  * 0.
 377  *
 378  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 379  * to make sure this function only returns 1 once for a given ordered extent.
 380  */
 381 int btrfs_dec_test_ordered_pending(struct btrfs_inode *inode,
 382                                    struct btrfs_ordered_extent **cached,
 383                                    u64 file_offset, u64 io_size, int uptodate)
 384 {
 385         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 386         struct rb_node *node;
 387         struct btrfs_ordered_extent *entry = NULL;
 388         unsigned long flags;
 389         int ret;
 390
 391         spin_lock_irqsave(&tree->lock, flags);
 392         if (cached && *cached) {
 393                 entry = *cached;
 394                 goto have_entry;
 395         }
 396
 397         node = tree_search(tree, file_offset);
 398         if (!node) {
 399                 ret = 1;
 400                 goto out;
 401         }
 402
 403         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 404 have_entry:
 405         if (!offset_in_entry(entry, file_offset)) {
 406                 ret = 1;
 407                 goto out;
 408         }
 409
 410         if (io_size > entry->bytes_left) {
 411                 btrfs_crit(inode->root->fs_info,
 412                            "bad ordered accounting left %llu size %llu",
 413                        entry->bytes_left, io_size);
 414         }
 415         entry->bytes_left -= io_size;
 416         if (!uptodate)
 417                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 418
 419         if (entry->bytes_left == 0) {
 420                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 421                 /* test_and_set_bit implies a barrier */
 422                 cond_wake_up_nomb(&entry->wait);
 423         } else {
 424                 ret = 1;
 425         }
 426 out:
 427         if (!ret && cached && entry) {
 428                 *cached = entry;
 429                 refcount_inc(&entry->refs);
 430         }
 431         spin_unlock_irqrestore(&tree->lock, flags);
 432         return ret == 0;
 433 }
 434
 435 /*
 436  * used to drop a reference on an ordered extent.  This will free
 437  * the extent if the last reference is dropped
 438  */
 439 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 440 {
 441         struct list_head *cur;
 442         struct btrfs_ordered_sum *sum;
 443
 444         trace_btrfs_ordered_extent_put(BTRFS_I(entry->inode), entry);
 445
 446         if (refcount_dec_and_test(&entry->refs)) {
 447                 ASSERT(list_empty(&entry->root_extent_list));
 448                 ASSERT(list_empty(&entry->log_list));
 449                 ASSERT(RB_EMPTY_NODE(&entry->rb_node));
 450                 if (entry->inode)
 451                         btrfs_add_delayed_iput(entry->inode);
 452                 while (!list_empty(&entry->list)) {
 453                         cur = entry->list.next;
 454                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 455                         list_del(&sum->list);
 456                         kvfree(sum);
 457                 }
 458                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
 459         }
 460 }
 461
 462 /*
 463  * remove an ordered extent from the tree.  No references are dropped
 464  * and waiters are woken up.
 465  */
 466 void btrfs_remove_ordered_extent(struct btrfs_inode *btrfs_inode,
 467                                  struct btrfs_ordered_extent *entry)
 468 {
 469         struct btrfs_ordered_inode_tree *tree;
 470         struct btrfs_root *root = btrfs_inode->root;
 471         struct btrfs_fs_info *fs_info = root->fs_info;
 472         struct rb_node *node;
 473         bool pending;
 474
 475         /* This is paired with btrfs_add_ordered_extent. */
 476         spin_lock(&btrfs_inode->lock);
 477         btrfs_mod_outstanding_extents(btrfs_inode, -1);
 478         spin_unlock(&btrfs_inode->lock);
 479         if (root != fs_info->tree_root)
 480                 btrfs_delalloc_release_metadata(btrfs_inode, entry->num_bytes,
 481                                                 false);
 482
 483         if (test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 484                 percpu_counter_add_batch(&fs_info->dio_bytes, -entry->num_bytes,
 485                                          fs_info->delalloc_batch);
 486
 487         tree = &btrfs_inode->ordered_tree;
 488         spin_lock_irq(&tree->lock);
 489         node = &entry->rb_node;
 490         rb_erase(node, &tree->tree);
 491         RB_CLEAR_NODE(node);
 492         if (tree->last == node)
 493                 tree->last = NULL;
 494         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 495         pending = test_and_clear_bit(BTRFS_ORDERED_PENDING, &entry->flags);
 496         spin_unlock_irq(&tree->lock);
 497
 498         /*
 499          * The current running transaction is waiting on us, we need to let it
 500          * know that we're complete and wake it up.
 501          */
 502         if (pending) {
 503                 struct btrfs_transaction *trans;
 504
 505                 /*
 506                  * The checks for trans are just a formality, it should be set,
 507                  * but if it isn't we don't want to deref/assert under the spin
 508                  * lock, so be nice and check if trans is set, but ASSERT() so
 509                  * if it isn't set a developer will notice.
 510                  */
 511                 spin_lock(&fs_info->trans_lock);
 512                 trans = fs_info->running_transaction;
 513                 if (trans)
 514                         refcount_inc(&trans->use_count);
 515                 spin_unlock(&fs_info->trans_lock);
 516
 517                 ASSERT(trans);
 518                 if (trans) {
 519                         if (atomic_dec_and_test(&trans->pending_ordered))
 520                                 wake_up(&trans->pending_wait);
 521                         btrfs_put_transaction(trans);
 522                 }
 523         }
 524
 525         spin_lock(&root->ordered_extent_lock);
 526         list_del_init(&entry->root_extent_list);
 527         root->nr_ordered_extents--;
 528
 529         trace_btrfs_ordered_extent_remove(btrfs_inode, entry);
 530
 531         if (!root->nr_ordered_extents) {
 532                 spin_lock(&fs_info->ordered_root_lock);
 533                 BUG_ON(list_empty(&root->ordered_root));
 534                 list_del_init(&root->ordered_root);
 535                 spin_unlock(&fs_info->ordered_root_lock);
 536         }
 537         spin_unlock(&root->ordered_extent_lock);
 538         wake_up(&entry->wait);
 539 }
 540
 541 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 542 {
 543         struct btrfs_ordered_extent *ordered;
 544
 545         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 546         btrfs_start_ordered_extent(ordered, 1);
 547         complete(&ordered->completion);
 548 }
 549
 550 /*
 551  * wait for all the ordered extents in a root.  This is done when balancing
 552  * space between drives.
 553  */
 554 u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
 555                                const u64 range_start, const u64 range_len)
 556 {
 557         struct btrfs_fs_info *fs_info = root->fs_info;
 558         LIST_HEAD(splice);
 559         LIST_HEAD(skipped);
 560         LIST_HEAD(works);
 561         struct btrfs_ordered_extent *ordered, *next;
 562         u64 count = 0;
 563         const u64 range_end = range_start + range_len;
 564
 565         mutex_lock(&root->ordered_extent_mutex);
 566         spin_lock(&root->ordered_extent_lock);
 567         list_splice_init(&root->ordered_extents, &splice);
 568         while (!list_empty(&splice) && nr) {
 569                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 570                                            root_extent_list);
 571
 572                 if (range_end <= ordered->disk_bytenr ||
 573                     ordered->disk_bytenr + ordered->disk_num_bytes <= range_start) {
 574                         list_move_tail(&ordered->root_extent_list, &skipped);
 575                         cond_resched_lock(&root->ordered_extent_lock);
 576                         continue;
 577                 }
 578
 579                 list_move_tail(&ordered->root_extent_list,
 580                                &root->ordered_extents);
 581                 refcount_inc(&ordered->refs);
 582                 spin_unlock(&root->ordered_extent_lock);
 583
 584                 btrfs_init_work(&ordered->flush_work,
 585                                 btrfs_run_ordered_extent_work, NULL, NULL);
 586                 list_add_tail(&ordered->work_list, &works);
 587                 btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work);
 588
 589                 cond_resched();
 590                 spin_lock(&root->ordered_extent_lock);
 591                 if (nr != U64_MAX)
 592                         nr--;
 593                 count++;
 594         }
 595         list_splice_tail(&skipped, &root->ordered_extents);
 596         list_splice_tail(&splice, &root->ordered_extents);
 597         spin_unlock(&root->ordered_extent_lock);
 598
 599         list_for_each_entry_safe(ordered, next, &works, work_list) {
 600                 list_del_init(&ordered->work_list);
 601                 wait_for_completion(&ordered->completion);
 602                 btrfs_put_ordered_extent(ordered);
 603                 cond_resched();
 604         }
 605         mutex_unlock(&root->ordered_extent_mutex);
 606
 607         return count;
 608 }
 609
 610 void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
 611                              const u64 range_start, const u64 range_len)
 612 {
 613         struct btrfs_root *root;
 614         struct list_head splice;
 615         u64 done;
 616
 617         INIT_LIST_HEAD(&splice);
 618
 619         mutex_lock(&fs_info->ordered_operations_mutex);
 620         spin_lock(&fs_info->ordered_root_lock);
 621         list_splice_init(&fs_info->ordered_roots, &splice);
 622         while (!list_empty(&splice) && nr) {
 623                 root = list_first_entry(&splice, struct btrfs_root,
 624                                         ordered_root);
 625                 root = btrfs_grab_root(root);
 626                 BUG_ON(!root);
 627                 list_move_tail(&root->ordered_root,
 628                                &fs_info->ordered_roots);
 629                 spin_unlock(&fs_info->ordered_root_lock);
 630
 631                 done = btrfs_wait_ordered_extents(root, nr,
 632                                                   range_start, range_len);
 633                 btrfs_put_root(root);
 634
 635                 spin_lock(&fs_info->ordered_root_lock);
 636                 if (nr != U64_MAX) {
 637                         nr -= done;
 638                 }
 639         }
 640         list_splice_tail(&splice, &fs_info->ordered_roots);
 641         spin_unlock(&fs_info->ordered_root_lock);
 642         mutex_unlock(&fs_info->ordered_operations_mutex);
 643 }
 644
 645 /*
 646  * Used to start IO or wait for a given ordered extent to finish.
 647  *
 648  * If wait is one, this effectively waits on page writeback for all the pages
 649  * in the extent, and it waits on the io completion code to insert
 650  * metadata into the btree corresponding to the extent
 651  */
 652 void btrfs_start_ordered_extent(struct btrfs_ordered_extent *entry, int wait)
 653 {
 654         u64 start = entry->file_offset;
 655         u64 end = start + entry->num_bytes - 1;
 656         struct btrfs_inode *inode = BTRFS_I(entry->inode);
 657
 658         trace_btrfs_ordered_extent_start(inode, entry);
 659
 660         /*
 661          * pages in the range can be dirty, clean or writeback.  We
 662          * start IO on any dirty ones so the wait doesn't stall waiting
 663          * for the flusher thread to find them
 664          */
 665         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 666                 filemap_fdatawrite_range(inode->vfs_inode.i_mapping, start, end);
 667         if (wait) {
 668                 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 669                                                  &entry->flags));
 670         }
 671 }
 672
 673 /*
 674  * Used to wait on ordered extents across a large range of bytes.
 675  */
 676 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 677 {
 678         int ret = 0;
 679         int ret_wb = 0;
 680         u64 end;
 681         u64 orig_end;
 682         struct btrfs_ordered_extent *ordered;
 683
 684         if (start + len < start) {
 685                 orig_end = INT_LIMIT(loff_t);
 686         } else {
 687                 orig_end = start + len - 1;
 688                 if (orig_end > INT_LIMIT(loff_t))
 689                         orig_end = INT_LIMIT(loff_t);
 690         }
 691
 692         /* start IO across the range first to instantiate any delalloc
 693          * extents
 694          */
 695         ret = btrfs_fdatawrite_range(inode, start, orig_end);
 696         if (ret)
 697                 return ret;
 698
 699         /*
 700          * If we have a writeback error don't return immediately. Wait first
 701          * for any ordered extents that haven't completed yet. This is to make
 702          * sure no one can dirty the same page ranges and call writepages()
 703          * before the ordered extents complete - to avoid failures (-EEXIST)
 704          * when adding the new ordered extents to the ordered tree.
 705          */
 706         ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 707
 708         end = orig_end;
 709         while (1) {
 710                 ordered = btrfs_lookup_first_ordered_extent(BTRFS_I(inode), end);
 711                 if (!ordered)
 712                         break;
 713                 if (ordered->file_offset > orig_end) {
 714                         btrfs_put_ordered_extent(ordered);
 715                         break;
 716                 }
 717                 if (ordered->file_offset + ordered->num_bytes <= start) {
 718                         btrfs_put_ordered_extent(ordered);
 719                         break;
 720                 }
 721                 btrfs_start_ordered_extent(ordered, 1);
 722                 end = ordered->file_offset;
 723                 /*
 724                  * If the ordered extent had an error save the error but don't
 725                  * exit without waiting first for all other ordered extents in
 726                  * the range to complete.
 727                  */
 728                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 729                         ret = -EIO;
 730                 btrfs_put_ordered_extent(ordered);
 731                 if (end == 0 || end == start)
 732                         break;
 733                 end--;
 734         }
 735         return ret_wb ? ret_wb : ret;
 736 }
 737
 738 /*
 739  * find an ordered extent corresponding to file_offset.  return NULL if
 740  * nothing is found, otherwise take a reference on the extent and return it
 741  */
 742 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct btrfs_inode *inode,
 743                                                          u64 file_offset)
 744 {
 745         struct btrfs_ordered_inode_tree *tree;
 746         struct rb_node *node;
 747         struct btrfs_ordered_extent *entry = NULL;
 748
 749         tree = &inode->ordered_tree;
 750         spin_lock_irq(&tree->lock);
 751         node = tree_search(tree, file_offset);
 752         if (!node)
 753                 goto out;
 754
 755         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 756         if (!offset_in_entry(entry, file_offset))
 757                 entry = NULL;
 758         if (entry)
 759                 refcount_inc(&entry->refs);
 760 out:
 761         spin_unlock_irq(&tree->lock);
 762         return entry;
 763 }
 764
 765 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 766  * extents that exist in the range, rather than just the start of the range.
 767  */
 768 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
 769                 struct btrfs_inode *inode, u64 file_offset, u64 len)
 770 {
 771         struct btrfs_ordered_inode_tree *tree;
 772         struct rb_node *node;
 773         struct btrfs_ordered_extent *entry = NULL;
 774
 775         tree = &inode->ordered_tree;
 776         spin_lock_irq(&tree->lock);
 777         node = tree_search(tree, file_offset);
 778         if (!node) {
 779                 node = tree_search(tree, file_offset + len);
 780                 if (!node)
 781                         goto out;
 782         }
 783
 784         while (1) {
 785                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 786                 if (range_overlaps(entry, file_offset, len))
 787                         break;
 788
 789                 if (entry->file_offset >= file_offset + len) {
 790                         entry = NULL;
 791                         break;
 792                 }
 793                 entry = NULL;
 794                 node = rb_next(node);
 795                 if (!node)
 796                         break;
 797         }
 798 out:
 799         if (entry)
 800                 refcount_inc(&entry->refs);
 801         spin_unlock_irq(&tree->lock);
 802         return entry;
 803 }
 804
 805 /*
 806  * Adds all ordered extents to the given list. The list ends up sorted by the
 807  * file_offset of the ordered extents.
 808  */
 809 void btrfs_get_ordered_extents_for_logging(struct btrfs_inode *inode,
 810                                            struct list_head *list)
 811 {
 812         struct btrfs_ordered_inode_tree *tree = &inode->ordered_tree;
 813         struct rb_node *n;
 814
 815         ASSERT(inode_is_locked(&inode->vfs_inode));
 816
 817         spin_lock_irq(&tree->lock);
 818         for (n = rb_first(&tree->tree); n; n = rb_next(n)) {
 819                 struct btrfs_ordered_extent *ordered;
 820
 821                 ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
 822
 823                 if (test_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
 824                         continue;
 825
 826                 ASSERT(list_empty(&ordered->log_list));
 827                 list_add_tail(&ordered->log_list, list);
 828                 refcount_inc(&ordered->refs);
 829         }
 830         spin_unlock_irq(&tree->lock);
 831 }
 832
 833 /*
 834  * lookup and return any extent before 'file_offset'.  NULL is returned
 835  * if none is found
 836  */
 837 struct btrfs_ordered_extent *
 838 btrfs_lookup_first_ordered_extent(struct btrfs_inode *inode, u64 file_offset)
 839 {
 840         struct btrfs_ordered_inode_tree *tree;
 841         struct rb_node *node;
 842         struct btrfs_ordered_extent *entry = NULL;
 843
 844         tree = &inode->ordered_tree;
 845         spin_lock_irq(&tree->lock);
 846         node = tree_search(tree, file_offset);
 847         if (!node)
 848                 goto out;
 849
 850         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 851         refcount_inc(&entry->refs);
 852 out:
 853         spin_unlock_irq(&tree->lock);
 854         return entry;
 855 }
 856
 857 /*
 858  * btrfs_flush_ordered_range - Lock the passed range and ensures all pending
 859  * ordered extents in it are run to completion.
 860  *
 861  * @inode:        Inode whose ordered tree is to be searched
 862  * @start:        Beginning of range to flush
 863  * @end:          Last byte of range to lock
 864  * @cached_state: If passed, will return the extent state responsible for the
 865  * locked range. It's the caller's responsibility to free the cached state.
 866  *
 867  * This function always returns with the given range locked, ensuring after it's
 868  * called no order extent can be pending.
 869  */
 870 void btrfs_lock_and_flush_ordered_range(struct btrfs_inode *inode, u64 start,
 871                                         u64 end,
 872                                         struct extent_state **cached_state)
 873 {
 874         struct btrfs_ordered_extent *ordered;
 875         struct extent_state *cache = NULL;
 876         struct extent_state **cachedp = &cache;
 877
 878         if (cached_state)
 879                 cachedp = cached_state;
 880
 881         while (1) {
 882                 lock_extent_bits(&inode->io_tree, start, end, cachedp);
 883                 ordered = btrfs_lookup_ordered_range(inode, start,
 884                                                      end - start + 1);
 885                 if (!ordered) {
 886                         /*
 887                          * If no external cached_state has been passed then
 888                          * decrement the extra ref taken for cachedp since we
 889                          * aren't exposing it outside of this function
 890                          */
 891                         if (!cached_state)
 892                                 refcount_dec(&cache->refs);
 893                         break;
 894                 }
 895                 unlock_extent_cached(&inode->io_tree, start, end, cachedp);
 896                 btrfs_start_ordered_extent(ordered, 1);
 897                 btrfs_put_ordered_extent(ordered);
 898         }
 899 }
 900
 901 int __init ordered_data_init(void)
 902 {
 903         btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
 904                                      sizeof(struct btrfs_ordered_extent), 0,
 905                                      SLAB_MEM_SPREAD,
 906                                      NULL);
 907         if (!btrfs_ordered_extent_cache)
 908                 return -ENOMEM;
 909
 910         return 0;
 911 }
 912
 913 void __cold ordered_data_exit(void)
 914 {
 915         kmem_cache_destroy(btrfs_ordered_extent_cache);
 916 }