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
  19 static struct kmem_cache *btrfs_ordered_extent_cache;
  20
  21 static u64 entry_end(struct btrfs_ordered_extent *entry)
  22 {
  23         if (entry->file_offset + entry->num_bytes < entry->file_offset)
  24                 return (u64)-1;
  25         return entry->file_offset + entry->num_bytes;
  26 }
  27
  28 /* returns NULL if the insertion worked, or it returns the node it did find
  29  * in the tree
  30  */
  31 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  32                                    struct rb_node *node)
  33 {
  34         struct rb_node **p = &root->rb_node;
  35         struct rb_node *parent = NULL;
  36         struct btrfs_ordered_extent *entry;
  37
  38         while (*p) {
  39                 parent = *p;
  40                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  41
  42                 if (file_offset < entry->file_offset)
  43                         p = &(*p)->rb_left;
  44                 else if (file_offset >= entry_end(entry))
  45                         p = &(*p)->rb_right;
  46                 else
  47                         return parent;
  48         }
  49
  50         rb_link_node(node, parent, p);
  51         rb_insert_color(node, root);
  52         return NULL;
  53 }
  54
  55 /*
  56  * look for a given offset in the tree, and if it can't be found return the
  57  * first lesser offset
  58  */
  59 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  60                                      struct rb_node **prev_ret)
  61 {
  62         struct rb_node *n = root->rb_node;
  63         struct rb_node *prev = NULL;
  64         struct rb_node *test;
  65         struct btrfs_ordered_extent *entry;
  66         struct btrfs_ordered_extent *prev_entry = NULL;
  67
  68         while (n) {
  69                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  70                 prev = n;
  71                 prev_entry = entry;
  72
  73                 if (file_offset < entry->file_offset)
  74                         n = n->rb_left;
  75                 else if (file_offset >= entry_end(entry))
  76                         n = n->rb_right;
  77                 else
  78                         return n;
  79         }
  80         if (!prev_ret)
  81                 return NULL;
  82
  83         while (prev && file_offset >= entry_end(prev_entry)) {
  84                 test = rb_next(prev);
  85                 if (!test)
  86                         break;
  87                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
  88                                       rb_node);
  89                 if (file_offset < entry_end(prev_entry))
  90                         break;
  91
  92                 prev = test;
  93         }
  94         if (prev)
  95                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
  96                                       rb_node);
  97         while (prev && file_offset < entry_end(prev_entry)) {
  98                 test = rb_prev(prev);
  99                 if (!test)
 100                         break;
 101                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 102                                       rb_node);
 103                 prev = test;
 104         }
 105         *prev_ret = prev;
 106         return NULL;
 107 }
 108
 109 /*
 110  * helper to check if a given offset is inside a given entry
 111  */
 112 static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
 113 {
 114         if (file_offset < entry->file_offset ||
 115             entry->file_offset + entry->num_bytes <= file_offset)
 116                 return 0;
 117         return 1;
 118 }
 119
 120 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 121                           u64 len)
 122 {
 123         if (file_offset + len <= entry->file_offset ||
 124             entry->file_offset + entry->num_bytes <= file_offset)
 125                 return 0;
 126         return 1;
 127 }
 128
 129 /*
 130  * look find the first ordered struct that has this offset, otherwise
 131  * the first one less than this offset
 132  */
 133 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 134                                           u64 file_offset)
 135 {
 136         struct rb_root *root = &tree->tree;
 137         struct rb_node *prev = NULL;
 138         struct rb_node *ret;
 139         struct btrfs_ordered_extent *entry;
 140
 141         if (tree->last) {
 142                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 143                                  rb_node);
 144                 if (offset_in_entry(entry, file_offset))
 145                         return tree->last;
 146         }
 147         ret = __tree_search(root, file_offset, &prev);
 148         if (!ret)
 149                 ret = prev;
 150         if (ret)
 151                 tree->last = ret;
 152         return ret;
 153 }
 154
 155 /* allocate and add a new ordered_extent into the per-inode tree.
 156  *
 157  * The tree is given a single reference on the ordered extent that was
 158  * inserted.
 159  */
 160 static int __btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 161                                       u64 disk_bytenr, u64 num_bytes,
 162                                       u64 disk_num_bytes, int type, int dio,
 163                                       int compress_type)
 164 {
 165         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 166         struct btrfs_root *root = BTRFS_I(inode)->root;
 167         struct btrfs_ordered_inode_tree *tree;
 168         struct rb_node *node;
 169         struct btrfs_ordered_extent *entry;
 170
 171         tree = &BTRFS_I(inode)->ordered_tree;
 172         entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 173         if (!entry)
 174                 return -ENOMEM;
 175
 176         entry->file_offset = file_offset;
 177         entry->disk_bytenr = disk_bytenr;
 178         entry->num_bytes = num_bytes;
 179         entry->disk_num_bytes = disk_num_bytes;
 180         entry->bytes_left = num_bytes;
 181         entry->inode = igrab(inode);
 182         entry->compress_type = compress_type;
 183         entry->truncated_len = (u64)-1;
 184         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 185                 set_bit(type, &entry->flags);
 186
 187         if (dio) {
 188                 percpu_counter_add_batch(&fs_info->dio_bytes, num_bytes,
 189                                          fs_info->delalloc_batch);
 190                 set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
 191         }
 192
 193         /* one ref for the tree */
 194         refcount_set(&entry->refs, 1);
 195         init_waitqueue_head(&entry->wait);
 196         INIT_LIST_HEAD(&entry->list);
 197         INIT_LIST_HEAD(&entry->root_extent_list);
 198         INIT_LIST_HEAD(&entry->work_list);
 199         init_completion(&entry->completion);
 200         INIT_LIST_HEAD(&entry->log_list);
 201         INIT_LIST_HEAD(&entry->trans_list);
 202
 203         trace_btrfs_ordered_extent_add(inode, entry);
 204
 205         spin_lock_irq(&tree->lock);
 206         node = tree_insert(&tree->tree, file_offset,
 207                            &entry->rb_node);
 208         if (node)
 209                 btrfs_panic(fs_info, -EEXIST,
 210                                 "inconsistency in ordered tree at offset %llu",
 211                                 file_offset);
 212         spin_unlock_irq(&tree->lock);
 213
 214         spin_lock(&root->ordered_extent_lock);
 215         list_add_tail(&entry->root_extent_list,
 216                       &root->ordered_extents);
 217         root->nr_ordered_extents++;
 218         if (root->nr_ordered_extents == 1) {
 219                 spin_lock(&fs_info->ordered_root_lock);
 220                 BUG_ON(!list_empty(&root->ordered_root));
 221                 list_add_tail(&root->ordered_root, &fs_info->ordered_roots);
 222                 spin_unlock(&fs_info->ordered_root_lock);
 223         }
 224         spin_unlock(&root->ordered_extent_lock);
 225
 226         /*
 227          * We don't need the count_max_extents here, we can assume that all of
 228          * that work has been done at higher layers, so this is truly the
 229          * smallest the extent is going to get.
 230          */
 231         spin_lock(&BTRFS_I(inode)->lock);
 232         btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);
 233         spin_unlock(&BTRFS_I(inode)->lock);
 234
 235         return 0;
 236 }
 237
 238 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 239                              u64 disk_bytenr, u64 num_bytes, u64 disk_num_bytes,
 240                              int type)
 241 {
 242         return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
 243                                           num_bytes, disk_num_bytes, type, 0,
 244                                           BTRFS_COMPRESS_NONE);
 245 }
 246
 247 int btrfs_add_ordered_extent_dio(struct inode *inode, u64 file_offset,
 248                                  u64 disk_bytenr, u64 num_bytes,
 249                                  u64 disk_num_bytes, int type)
 250 {
 251         return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
 252                                           num_bytes, disk_num_bytes, type, 1,
 253                                           BTRFS_COMPRESS_NONE);
 254 }
 255
 256 int btrfs_add_ordered_extent_compress(struct inode *inode, u64 file_offset,
 257                                       u64 disk_bytenr, u64 num_bytes,
 258                                       u64 disk_num_bytes, int type,
 259                                       int compress_type)
 260 {
 261         return __btrfs_add_ordered_extent(inode, file_offset, disk_bytenr,
 262                                           num_bytes, disk_num_bytes, type, 0,
 263                                           compress_type);
 264 }
 265
 266 /*
 267  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 268  * when an ordered extent is finished.  If the list covers more than one
 269  * ordered extent, it is split across multiples.
 270  */
 271 void btrfs_add_ordered_sum(struct btrfs_ordered_extent *entry,
 272                            struct btrfs_ordered_sum *sum)
 273 {
 274         struct btrfs_ordered_inode_tree *tree;
 275
 276         tree = &BTRFS_I(entry->inode)->ordered_tree;
 277         spin_lock_irq(&tree->lock);
 278         list_add_tail(&sum->list, &entry->list);
 279         spin_unlock_irq(&tree->lock);
 280 }
 281
 282 /*
 283  * this is used to account for finished IO across a given range
 284  * of the file.  The IO may span ordered extents.  If
 285  * a given ordered_extent is completely done, 1 is returned, otherwise
 286  * 0.
 287  *
 288  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 289  * to make sure this function only returns 1 once for a given ordered extent.
 290  *
 291  * file_offset is updated to one byte past the range that is recorded as
 292  * complete.  This allows you to walk forward in the file.
 293  */
 294 int btrfs_dec_test_first_ordered_pending(struct inode *inode,
 295                                    struct btrfs_ordered_extent **cached,
 296                                    u64 *file_offset, u64 io_size, int uptodate)
 297 {
 298         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 299         struct btrfs_ordered_inode_tree *tree;
 300         struct rb_node *node;
 301         struct btrfs_ordered_extent *entry = NULL;
 302         int ret;
 303         unsigned long flags;
 304         u64 dec_end;
 305         u64 dec_start;
 306         u64 to_dec;
 307
 308         tree = &BTRFS_I(inode)->ordered_tree;
 309         spin_lock_irqsave(&tree->lock, flags);
 310         node = tree_search(tree, *file_offset);
 311         if (!node) {
 312                 ret = 1;
 313                 goto out;
 314         }
 315
 316         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 317         if (!offset_in_entry(entry, *file_offset)) {
 318                 ret = 1;
 319                 goto out;
 320         }
 321
 322         dec_start = max(*file_offset, entry->file_offset);
 323         dec_end = min(*file_offset + io_size,
 324                       entry->file_offset + entry->num_bytes);
 325         *file_offset = dec_end;
 326         if (dec_start > dec_end) {
 327                 btrfs_crit(fs_info, "bad ordering dec_start %llu end %llu",
 328                            dec_start, dec_end);
 329         }
 330         to_dec = dec_end - dec_start;
 331         if (to_dec > entry->bytes_left) {
 332                 btrfs_crit(fs_info,
 333                            "bad ordered accounting left %llu size %llu",
 334                            entry->bytes_left, to_dec);
 335         }
 336         entry->bytes_left -= to_dec;
 337         if (!uptodate)
 338                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 339
 340         if (entry->bytes_left == 0) {
 341                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 342                 /* test_and_set_bit implies a barrier */
 343                 cond_wake_up_nomb(&entry->wait);
 344         } else {
 345                 ret = 1;
 346         }
 347 out:
 348         if (!ret && cached && entry) {
 349                 *cached = entry;
 350                 refcount_inc(&entry->refs);
 351         }
 352         spin_unlock_irqrestore(&tree->lock, flags);
 353         return ret == 0;
 354 }
 355
 356 /*
 357  * this is used to account for finished IO across a given range
 358  * of the file.  The IO should not span ordered extents.  If
 359  * a given ordered_extent is completely done, 1 is returned, otherwise
 360  * 0.
 361  *
 362  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 363  * to make sure this function only returns 1 once for a given ordered extent.
 364  */
 365 int btrfs_dec_test_ordered_pending(struct inode *inode,
 366                                    struct btrfs_ordered_extent **cached,
 367                                    u64 file_offset, u64 io_size, int uptodate)
 368 {
 369         struct btrfs_ordered_inode_tree *tree;
 370         struct rb_node *node;
 371         struct btrfs_ordered_extent *entry = NULL;
 372         unsigned long flags;
 373         int ret;
 374
 375         tree = &BTRFS_I(inode)->ordered_tree;
 376         spin_lock_irqsave(&tree->lock, flags);
 377         if (cached && *cached) {
 378                 entry = *cached;
 379                 goto have_entry;
 380         }
 381
 382         node = tree_search(tree, file_offset);
 383         if (!node) {
 384                 ret = 1;
 385                 goto out;
 386         }
 387
 388         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 389 have_entry:
 390         if (!offset_in_entry(entry, file_offset)) {
 391                 ret = 1;
 392                 goto out;
 393         }
 394
 395         if (io_size > entry->bytes_left) {
 396                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
 397                            "bad ordered accounting left %llu size %llu",
 398                        entry->bytes_left, io_size);
 399         }
 400         entry->bytes_left -= io_size;
 401         if (!uptodate)
 402                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 403
 404         if (entry->bytes_left == 0) {
 405                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 406                 /* test_and_set_bit implies a barrier */
 407                 cond_wake_up_nomb(&entry->wait);
 408         } else {
 409                 ret = 1;
 410         }
 411 out:
 412         if (!ret && cached && entry) {
 413                 *cached = entry;
 414                 refcount_inc(&entry->refs);
 415         }
 416         spin_unlock_irqrestore(&tree->lock, flags);
 417         return ret == 0;
 418 }
 419
 420 /*
 421  * used to drop a reference on an ordered extent.  This will free
 422  * the extent if the last reference is dropped
 423  */
 424 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 425 {
 426         struct list_head *cur;
 427         struct btrfs_ordered_sum *sum;
 428
 429         trace_btrfs_ordered_extent_put(entry->inode, entry);
 430
 431         if (refcount_dec_and_test(&entry->refs)) {
 432                 ASSERT(list_empty(&entry->log_list));
 433                 ASSERT(list_empty(&entry->trans_list));
 434                 ASSERT(list_empty(&entry->root_extent_list));
 435                 ASSERT(RB_EMPTY_NODE(&entry->rb_node));
 436                 if (entry->inode)
 437                         btrfs_add_delayed_iput(entry->inode);
 438                 while (!list_empty(&entry->list)) {
 439                         cur = entry->list.next;
 440                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 441                         list_del(&sum->list);
 442                         kvfree(sum);
 443                 }
 444                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
 445         }
 446 }
 447
 448 /*
 449  * remove an ordered extent from the tree.  No references are dropped
 450  * and waiters are woken up.
 451  */
 452 void btrfs_remove_ordered_extent(struct inode *inode,
 453                                  struct btrfs_ordered_extent *entry)
 454 {
 455         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 456         struct btrfs_ordered_inode_tree *tree;
 457         struct btrfs_inode *btrfs_inode = BTRFS_I(inode);
 458         struct btrfs_root *root = btrfs_inode->root;
 459         struct rb_node *node;
 460
 461         /* This is paired with btrfs_add_ordered_extent. */
 462         spin_lock(&btrfs_inode->lock);
 463         btrfs_mod_outstanding_extents(btrfs_inode, -1);
 464         spin_unlock(&btrfs_inode->lock);
 465         if (root != fs_info->tree_root)
 466                 btrfs_delalloc_release_metadata(btrfs_inode, entry->num_bytes,
 467                                                 false);
 468
 469         if (test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 470                 percpu_counter_add_batch(&fs_info->dio_bytes, -entry->num_bytes,
 471                                          fs_info->delalloc_batch);
 472
 473         tree = &btrfs_inode->ordered_tree;
 474         spin_lock_irq(&tree->lock);
 475         node = &entry->rb_node;
 476         rb_erase(node, &tree->tree);
 477         RB_CLEAR_NODE(node);
 478         if (tree->last == node)
 479                 tree->last = NULL;
 480         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 481         spin_unlock_irq(&tree->lock);
 482
 483         spin_lock(&root->ordered_extent_lock);
 484         list_del_init(&entry->root_extent_list);
 485         root->nr_ordered_extents--;
 486
 487         trace_btrfs_ordered_extent_remove(inode, entry);
 488
 489         if (!root->nr_ordered_extents) {
 490                 spin_lock(&fs_info->ordered_root_lock);
 491                 BUG_ON(list_empty(&root->ordered_root));
 492                 list_del_init(&root->ordered_root);
 493                 spin_unlock(&fs_info->ordered_root_lock);
 494         }
 495         spin_unlock(&root->ordered_extent_lock);
 496         wake_up(&entry->wait);
 497 }
 498
 499 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 500 {
 501         struct btrfs_ordered_extent *ordered;
 502
 503         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 504         btrfs_start_ordered_extent(ordered->inode, ordered, 1);
 505         complete(&ordered->completion);
 506 }
 507
 508 /*
 509  * wait for all the ordered extents in a root.  This is done when balancing
 510  * space between drives.
 511  */
 512 u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
 513                                const u64 range_start, const u64 range_len)
 514 {
 515         struct btrfs_fs_info *fs_info = root->fs_info;
 516         LIST_HEAD(splice);
 517         LIST_HEAD(skipped);
 518         LIST_HEAD(works);
 519         struct btrfs_ordered_extent *ordered, *next;
 520         u64 count = 0;
 521         const u64 range_end = range_start + range_len;
 522
 523         mutex_lock(&root->ordered_extent_mutex);
 524         spin_lock(&root->ordered_extent_lock);
 525         list_splice_init(&root->ordered_extents, &splice);
 526         while (!list_empty(&splice) && nr) {
 527                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 528                                            root_extent_list);
 529
 530                 if (range_end <= ordered->disk_bytenr ||
 531                     ordered->disk_bytenr + ordered->disk_num_bytes <= range_start) {
 532                         list_move_tail(&ordered->root_extent_list, &skipped);
 533                         cond_resched_lock(&root->ordered_extent_lock);
 534                         continue;
 535                 }
 536
 537                 list_move_tail(&ordered->root_extent_list,
 538                                &root->ordered_extents);
 539                 refcount_inc(&ordered->refs);
 540                 spin_unlock(&root->ordered_extent_lock);
 541
 542                 btrfs_init_work(&ordered->flush_work,
 543                                 btrfs_run_ordered_extent_work, NULL, NULL);
 544                 list_add_tail(&ordered->work_list, &works);
 545                 btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work);
 546
 547                 cond_resched();
 548                 spin_lock(&root->ordered_extent_lock);
 549                 if (nr != U64_MAX)
 550                         nr--;
 551                 count++;
 552         }
 553         list_splice_tail(&skipped, &root->ordered_extents);
 554         list_splice_tail(&splice, &root->ordered_extents);
 555         spin_unlock(&root->ordered_extent_lock);
 556
 557         list_for_each_entry_safe(ordered, next, &works, work_list) {
 558                 list_del_init(&ordered->work_list);
 559                 wait_for_completion(&ordered->completion);
 560                 btrfs_put_ordered_extent(ordered);
 561                 cond_resched();
 562         }
 563         mutex_unlock(&root->ordered_extent_mutex);
 564
 565         return count;
 566 }
 567
 568 void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
 569                              const u64 range_start, const u64 range_len)
 570 {
 571         struct btrfs_root *root;
 572         struct list_head splice;
 573         u64 done;
 574
 575         INIT_LIST_HEAD(&splice);
 576
 577         mutex_lock(&fs_info->ordered_operations_mutex);
 578         spin_lock(&fs_info->ordered_root_lock);
 579         list_splice_init(&fs_info->ordered_roots, &splice);
 580         while (!list_empty(&splice) && nr) {
 581                 root = list_first_entry(&splice, struct btrfs_root,
 582                                         ordered_root);
 583                 root = btrfs_grab_root(root);
 584                 BUG_ON(!root);
 585                 list_move_tail(&root->ordered_root,
 586                                &fs_info->ordered_roots);
 587                 spin_unlock(&fs_info->ordered_root_lock);
 588
 589                 done = btrfs_wait_ordered_extents(root, nr,
 590                                                   range_start, range_len);
 591                 btrfs_put_root(root);
 592
 593                 spin_lock(&fs_info->ordered_root_lock);
 594                 if (nr != U64_MAX) {
 595                         nr -= done;
 596                 }
 597         }
 598         list_splice_tail(&splice, &fs_info->ordered_roots);
 599         spin_unlock(&fs_info->ordered_root_lock);
 600         mutex_unlock(&fs_info->ordered_operations_mutex);
 601 }
 602
 603 /*
 604  * Used to start IO or wait for a given ordered extent to finish.
 605  *
 606  * If wait is one, this effectively waits on page writeback for all the pages
 607  * in the extent, and it waits on the io completion code to insert
 608  * metadata into the btree corresponding to the extent
 609  */
 610 void btrfs_start_ordered_extent(struct inode *inode,
 611                                        struct btrfs_ordered_extent *entry,
 612                                        int wait)
 613 {
 614         u64 start = entry->file_offset;
 615         u64 end = start + entry->num_bytes - 1;
 616
 617         trace_btrfs_ordered_extent_start(inode, entry);
 618
 619         /*
 620          * pages in the range can be dirty, clean or writeback.  We
 621          * start IO on any dirty ones so the wait doesn't stall waiting
 622          * for the flusher thread to find them
 623          */
 624         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 625                 filemap_fdatawrite_range(inode->i_mapping, start, end);
 626         if (wait) {
 627                 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 628                                                  &entry->flags));
 629         }
 630 }
 631
 632 /*
 633  * Used to wait on ordered extents across a large range of bytes.
 634  */
 635 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 636 {
 637         int ret = 0;
 638         int ret_wb = 0;
 639         u64 end;
 640         u64 orig_end;
 641         struct btrfs_ordered_extent *ordered;
 642
 643         if (start + len < start) {
 644                 orig_end = INT_LIMIT(loff_t);
 645         } else {
 646                 orig_end = start + len - 1;
 647                 if (orig_end > INT_LIMIT(loff_t))
 648                         orig_end = INT_LIMIT(loff_t);
 649         }
 650
 651         /* start IO across the range first to instantiate any delalloc
 652          * extents
 653          */
 654         ret = btrfs_fdatawrite_range(inode, start, orig_end);
 655         if (ret)
 656                 return ret;
 657
 658         /*
 659          * If we have a writeback error don't return immediately. Wait first
 660          * for any ordered extents that haven't completed yet. This is to make
 661          * sure no one can dirty the same page ranges and call writepages()
 662          * before the ordered extents complete - to avoid failures (-EEXIST)
 663          * when adding the new ordered extents to the ordered tree.
 664          */
 665         ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 666
 667         end = orig_end;
 668         while (1) {
 669                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
 670                 if (!ordered)
 671                         break;
 672                 if (ordered->file_offset > orig_end) {
 673                         btrfs_put_ordered_extent(ordered);
 674                         break;
 675                 }
 676                 if (ordered->file_offset + ordered->num_bytes <= start) {
 677                         btrfs_put_ordered_extent(ordered);
 678                         break;
 679                 }
 680                 btrfs_start_ordered_extent(inode, ordered, 1);
 681                 end = ordered->file_offset;
 682                 /*
 683                  * If the ordered extent had an error save the error but don't
 684                  * exit without waiting first for all other ordered extents in
 685                  * the range to complete.
 686                  */
 687                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 688                         ret = -EIO;
 689                 btrfs_put_ordered_extent(ordered);
 690                 if (end == 0 || end == start)
 691                         break;
 692                 end--;
 693         }
 694         return ret_wb ? ret_wb : ret;
 695 }
 696
 697 /*
 698  * find an ordered extent corresponding to file_offset.  return NULL if
 699  * nothing is found, otherwise take a reference on the extent and return it
 700  */
 701 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
 702                                                          u64 file_offset)
 703 {
 704         struct btrfs_ordered_inode_tree *tree;
 705         struct rb_node *node;
 706         struct btrfs_ordered_extent *entry = NULL;
 707
 708         tree = &BTRFS_I(inode)->ordered_tree;
 709         spin_lock_irq(&tree->lock);
 710         node = tree_search(tree, file_offset);
 711         if (!node)
 712                 goto out;
 713
 714         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 715         if (!offset_in_entry(entry, file_offset))
 716                 entry = NULL;
 717         if (entry)
 718                 refcount_inc(&entry->refs);
 719 out:
 720         spin_unlock_irq(&tree->lock);
 721         return entry;
 722 }
 723
 724 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 725  * extents that exist in the range, rather than just the start of the range.
 726  */
 727 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
 728                 struct btrfs_inode *inode, u64 file_offset, u64 len)
 729 {
 730         struct btrfs_ordered_inode_tree *tree;
 731         struct rb_node *node;
 732         struct btrfs_ordered_extent *entry = NULL;
 733
 734         tree = &inode->ordered_tree;
 735         spin_lock_irq(&tree->lock);
 736         node = tree_search(tree, file_offset);
 737         if (!node) {
 738                 node = tree_search(tree, file_offset + len);
 739                 if (!node)
 740                         goto out;
 741         }
 742
 743         while (1) {
 744                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 745                 if (range_overlaps(entry, file_offset, len))
 746                         break;
 747
 748                 if (entry->file_offset >= file_offset + len) {
 749                         entry = NULL;
 750                         break;
 751                 }
 752                 entry = NULL;
 753                 node = rb_next(node);
 754                 if (!node)
 755                         break;
 756         }
 757 out:
 758         if (entry)
 759                 refcount_inc(&entry->refs);
 760         spin_unlock_irq(&tree->lock);
 761         return entry;
 762 }
 763
 764 /*
 765  * lookup and return any extent before 'file_offset'.  NULL is returned
 766  * if none is found
 767  */
 768 struct btrfs_ordered_extent *
 769 btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
 770 {
 771         struct btrfs_ordered_inode_tree *tree;
 772         struct rb_node *node;
 773         struct btrfs_ordered_extent *entry = NULL;
 774
 775         tree = &BTRFS_I(inode)->ordered_tree;
 776         spin_lock_irq(&tree->lock);
 777         node = tree_search(tree, file_offset);
 778         if (!node)
 779                 goto out;
 780
 781         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 782         refcount_inc(&entry->refs);
 783 out:
 784         spin_unlock_irq(&tree->lock);
 785         return entry;
 786 }
 787
 788 /*
 789  * search the ordered extents for one corresponding to 'offset' and
 790  * try to find a checksum.  This is used because we allow pages to
 791  * be reclaimed before their checksum is actually put into the btree
 792  */
 793 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
 794                            u8 *sum, int len)
 795 {
 796         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 797         struct btrfs_ordered_sum *ordered_sum;
 798         struct btrfs_ordered_extent *ordered;
 799         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 800         unsigned long num_sectors;
 801         unsigned long i;
 802         u32 sectorsize = btrfs_inode_sectorsize(inode);
 803         const u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 804         int index = 0;
 805
 806         ordered = btrfs_lookup_ordered_extent(inode, offset);
 807         if (!ordered)
 808                 return 0;
 809
 810         spin_lock_irq(&tree->lock);
 811         list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
 812                 if (disk_bytenr >= ordered_sum->bytenr &&
 813                     disk_bytenr < ordered_sum->bytenr + ordered_sum->len) {
 814                         i = (disk_bytenr - ordered_sum->bytenr) >>
 815                             inode->i_sb->s_blocksize_bits;
 816                         num_sectors = ordered_sum->len >>
 817                                       inode->i_sb->s_blocksize_bits;
 818                         num_sectors = min_t(int, len - index, num_sectors - i);
 819                         memcpy(sum + index, ordered_sum->sums + i * csum_size,
 820                                num_sectors * csum_size);
 821
 822                         index += (int)num_sectors * csum_size;
 823                         if (index == len)
 824                                 goto out;
 825                         disk_bytenr += num_sectors * sectorsize;
 826                 }
 827         }
 828 out:
 829         spin_unlock_irq(&tree->lock);
 830         btrfs_put_ordered_extent(ordered);
 831         return index;
 832 }
 833
 834 /*
 835  * btrfs_flush_ordered_range - Lock the passed range and ensures all pending
 836  * ordered extents in it are run to completion.
 837  *
 838  * @inode:        Inode whose ordered tree is to be searched
 839  * @start:        Beginning of range to flush
 840  * @end:          Last byte of range to lock
 841  * @cached_state: If passed, will return the extent state responsible for the
 842  * locked range. It's the caller's responsibility to free the cached state.
 843  *
 844  * This function always returns with the given range locked, ensuring after it's
 845  * called no order extent can be pending.
 846  */
 847 void btrfs_lock_and_flush_ordered_range(struct btrfs_inode *inode, u64 start,
 848                                         u64 end,
 849                                         struct extent_state **cached_state)
 850 {
 851         struct btrfs_ordered_extent *ordered;
 852         struct extent_state *cache = NULL;
 853         struct extent_state **cachedp = &cache;
 854
 855         if (cached_state)
 856                 cachedp = cached_state;
 857
 858         while (1) {
 859                 lock_extent_bits(&inode->io_tree, start, end, cachedp);
 860                 ordered = btrfs_lookup_ordered_range(inode, start,
 861                                                      end - start + 1);
 862                 if (!ordered) {
 863                         /*
 864                          * If no external cached_state has been passed then
 865                          * decrement the extra ref taken for cachedp since we
 866                          * aren't exposing it outside of this function
 867                          */
 868                         if (!cached_state)
 869                                 refcount_dec(&cache->refs);
 870                         break;
 871                 }
 872                 unlock_extent_cached(&inode->io_tree, start, end, cachedp);
 873                 btrfs_start_ordered_extent(&inode->vfs_inode, ordered, 1);
 874                 btrfs_put_ordered_extent(ordered);
 875         }
 876 }
 877
 878 int __init ordered_data_init(void)
 879 {
 880         btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
 881                                      sizeof(struct btrfs_ordered_extent), 0,
 882                                      SLAB_MEM_SPREAD,
 883                                      NULL);
 884         if (!btrfs_ordered_extent_cache)
 885                 return -ENOMEM;
 886
 887         return 0;
 888 }
 889
 890 void __cold ordered_data_exit(void)
 891 {
 892         kmem_cache_destroy(btrfs_ordered_extent_cache);
 893 }