fs/btrfs/ordered-data.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/gfp.h>
  20 #include <linux/slab.h>
  21 #include <linux/blkdev.h>
  22 #include <linux/writeback.h>
  23 #include <linux/pagevec.h>
  24 #include "ctree.h"
  25 #include "transaction.h"
  26 #include "btrfs_inode.h"
  27 #include "extent_io.h"
  28
  29 static u64 entry_end(struct btrfs_ordered_extent *entry)
  30 {
  31         if (entry->file_offset + entry->len < entry->file_offset)
  32                 return (u64)-1;
  33         return entry->file_offset + entry->len;
  34 }
  35
  36 /* returns NULL if the insertion worked, or it returns the node it did find
  37  * in the tree
  38  */
  39 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  40                                    struct rb_node *node)
  41 {
  42         struct rb_node **p = &root->rb_node;
  43         struct rb_node *parent = NULL;
  44         struct btrfs_ordered_extent *entry;
  45
  46         while (*p) {
  47                 parent = *p;
  48                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  49
  50                 if (file_offset < entry->file_offset)
  51                         p = &(*p)->rb_left;
  52                 else if (file_offset >= entry_end(entry))
  53                         p = &(*p)->rb_right;
  54                 else
  55                         return parent;
  56         }
  57
  58         rb_link_node(node, parent, p);
  59         rb_insert_color(node, root);
  60         return NULL;
  61 }
  62
  63 /*
  64  * look for a given offset in the tree, and if it can't be found return the
  65  * first lesser offset
  66  */
  67 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  68                                      struct rb_node **prev_ret)
  69 {
  70         struct rb_node *n = root->rb_node;
  71         struct rb_node *prev = NULL;
  72         struct rb_node *test;
  73         struct btrfs_ordered_extent *entry;
  74         struct btrfs_ordered_extent *prev_entry = NULL;
  75
  76         while (n) {
  77                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  78                 prev = n;
  79                 prev_entry = entry;
  80
  81                 if (file_offset < entry->file_offset)
  82                         n = n->rb_left;
  83                 else if (file_offset >= entry_end(entry))
  84                         n = n->rb_right;
  85                 else
  86                         return n;
  87         }
  88         if (!prev_ret)
  89                 return NULL;
  90
  91         while (prev && file_offset >= entry_end(prev_entry)) {
  92                 test = rb_next(prev);
  93                 if (!test)
  94                         break;
  95                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
  96                                       rb_node);
  97                 if (file_offset < entry_end(prev_entry))
  98                         break;
  99
 100                 prev = test;
 101         }
 102         if (prev)
 103                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
 104                                       rb_node);
 105         while (prev && file_offset < entry_end(prev_entry)) {
 106                 test = rb_prev(prev);
 107                 if (!test)
 108                         break;
 109                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 110                                       rb_node);
 111                 prev = test;
 112         }
 113         *prev_ret = prev;
 114         return NULL;
 115 }
 116
 117 /*
 118  * helper to check if a given offset is inside a given entry
 119  */
 120 static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
 121 {
 122         if (file_offset < entry->file_offset ||
 123             entry->file_offset + entry->len <= file_offset)
 124                 return 0;
 125         return 1;
 126 }
 127
 128 /*
 129  * look find the first ordered struct that has this offset, otherwise
 130  * the first one less than this offset
 131  */
 132 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 133                                           u64 file_offset)
 134 {
 135         struct rb_root *root = &tree->tree;
 136         struct rb_node *prev;
 137         struct rb_node *ret;
 138         struct btrfs_ordered_extent *entry;
 139
 140         if (tree->last) {
 141                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 142                                  rb_node);
 143                 if (offset_in_entry(entry, file_offset))
 144                         return tree->last;
 145         }
 146         ret = __tree_search(root, file_offset, &prev);
 147         if (!ret)
 148                 ret = prev;
 149         if (ret)
 150                 tree->last = ret;
 151         return ret;
 152 }
 153
 154 /* allocate and add a new ordered_extent into the per-inode tree.
 155  * file_offset is the logical offset in the file
 156  *
 157  * start is the disk block number of an extent already reserved in the
 158  * extent allocation tree
 159  *
 160  * len is the length of the extent
 161  *
 162  * The tree is given a single reference on the ordered extent that was
 163  * inserted.
 164  */
 165 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 166                              u64 start, u64 len, u64 disk_len, int type)
 167 {
 168         struct btrfs_ordered_inode_tree *tree;
 169         struct rb_node *node;
 170         struct btrfs_ordered_extent *entry;
 171
 172         tree = &BTRFS_I(inode)->ordered_tree;
 173         entry = kzalloc(sizeof(*entry), GFP_NOFS);
 174         if (!entry)
 175                 return -ENOMEM;
 176
 177         mutex_lock(&tree->mutex);
 178         entry->file_offset = file_offset;
 179         entry->start = start;
 180         entry->len = len;
 181         entry->disk_len = disk_len;
 182         entry->bytes_left = len;
 183         entry->inode = inode;
 184         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 185                 set_bit(type, &entry->flags);
 186
 187         /* one ref for the tree */
 188         atomic_set(&entry->refs, 1);
 189         init_waitqueue_head(&entry->wait);
 190         INIT_LIST_HEAD(&entry->list);
 191         INIT_LIST_HEAD(&entry->root_extent_list);
 192
 193         node = tree_insert(&tree->tree, file_offset,
 194                            &entry->rb_node);
 195         BUG_ON(node);
 196
 197         spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
 198         list_add_tail(&entry->root_extent_list,
 199                       &BTRFS_I(inode)->root->fs_info->ordered_extents);
 200         spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
 201
 202         mutex_unlock(&tree->mutex);
 203         BUG_ON(node);
 204         return 0;
 205 }
 206
 207 /*
 208  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 209  * when an ordered extent is finished.  If the list covers more than one
 210  * ordered extent, it is split across multiples.
 211  */
 212 int btrfs_add_ordered_sum(struct inode *inode,
 213                           struct btrfs_ordered_extent *entry,
 214                           struct btrfs_ordered_sum *sum)
 215 {
 216         struct btrfs_ordered_inode_tree *tree;
 217
 218         tree = &BTRFS_I(inode)->ordered_tree;
 219         mutex_lock(&tree->mutex);
 220         list_add_tail(&sum->list, &entry->list);
 221         mutex_unlock(&tree->mutex);
 222         return 0;
 223 }
 224
 225 /*
 226  * this is used to account for finished IO across a given range
 227  * of the file.  The IO should not span ordered extents.  If
 228  * a given ordered_extent is completely done, 1 is returned, otherwise
 229  * 0.
 230  *
 231  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 232  * to make sure this function only returns 1 once for a given ordered extent.
 233  */
 234 int btrfs_dec_test_ordered_pending(struct inode *inode,
 235                                    u64 file_offset, u64 io_size)
 236 {
 237         struct btrfs_ordered_inode_tree *tree;
 238         struct rb_node *node;
 239         struct btrfs_ordered_extent *entry;
 240         int ret;
 241
 242         tree = &BTRFS_I(inode)->ordered_tree;
 243         mutex_lock(&tree->mutex);
 244         node = tree_search(tree, file_offset);
 245         if (!node) {
 246                 ret = 1;
 247                 goto out;
 248         }
 249
 250         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 251         if (!offset_in_entry(entry, file_offset)) {
 252                 ret = 1;
 253                 goto out;
 254         }
 255
 256         if (io_size > entry->bytes_left) {
 257                 printk(KERN_CRIT "bad ordered accounting left %llu size %llu\n",
 258                        (unsigned long long)entry->bytes_left,
 259                        (unsigned long long)io_size);
 260         }
 261         entry->bytes_left -= io_size;
 262         if (entry->bytes_left == 0)
 263                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 264         else
 265                 ret = 1;
 266 out:
 267         mutex_unlock(&tree->mutex);
 268         return ret == 0;
 269 }
 270
 271 /*
 272  * used to drop a reference on an ordered extent.  This will free
 273  * the extent if the last reference is dropped
 274  */
 275 int btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 276 {
 277         struct list_head *cur;
 278         struct btrfs_ordered_sum *sum;
 279
 280         if (atomic_dec_and_test(&entry->refs)) {
 281                 while (!list_empty(&entry->list)) {
 282                         cur = entry->list.next;
 283                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 284                         list_del(&sum->list);
 285                         kfree(sum);
 286                 }
 287                 kfree(entry);
 288         }
 289         return 0;
 290 }
 291
 292 /*
 293  * remove an ordered extent from the tree.  No references are dropped
 294  * but, anyone waiting on this extent is woken up.
 295  */
 296 int btrfs_remove_ordered_extent(struct inode *inode,
 297                                 struct btrfs_ordered_extent *entry)
 298 {
 299         struct btrfs_ordered_inode_tree *tree;
 300         struct rb_node *node;
 301
 302         tree = &BTRFS_I(inode)->ordered_tree;
 303         mutex_lock(&tree->mutex);
 304         node = &entry->rb_node;
 305         rb_erase(node, &tree->tree);
 306         tree->last = NULL;
 307         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 308
 309         spin_lock(&BTRFS_I(inode)->accounting_lock);
 310         BTRFS_I(inode)->outstanding_extents--;
 311         spin_unlock(&BTRFS_I(inode)->accounting_lock);
 312         btrfs_unreserve_metadata_for_delalloc(BTRFS_I(inode)->root,
 313                                               inode, 1);
 314
 315         spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
 316         list_del_init(&entry->root_extent_list);
 317
 318         /*
 319          * we have no more ordered extents for this inode and
 320          * no dirty pages.  We can safely remove it from the
 321          * list of ordered extents
 322          */
 323         if (RB_EMPTY_ROOT(&tree->tree) &&
 324             !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) {
 325                 list_del_init(&BTRFS_I(inode)->ordered_operations);
 326         }
 327         spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
 328
 329         mutex_unlock(&tree->mutex);
 330         wake_up(&entry->wait);
 331         return 0;
 332 }
 333
 334 /*
 335  * wait for all the ordered extents in a root.  This is done when balancing
 336  * space between drives.
 337  */
 338 int btrfs_wait_ordered_extents(struct btrfs_root *root, int nocow_only)
 339 {
 340         struct list_head splice;
 341         struct list_head *cur;
 342         struct btrfs_ordered_extent *ordered;
 343         struct inode *inode;
 344
 345         INIT_LIST_HEAD(&splice);
 346
 347         spin_lock(&root->fs_info->ordered_extent_lock);
 348         list_splice_init(&root->fs_info->ordered_extents, &splice);
 349         while (!list_empty(&splice)) {
 350                 cur = splice.next;
 351                 ordered = list_entry(cur, struct btrfs_ordered_extent,
 352                                      root_extent_list);
 353                 if (nocow_only &&
 354                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags) &&
 355                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags)) {
 356                         list_move(&ordered->root_extent_list,
 357                                   &root->fs_info->ordered_extents);
 358                         cond_resched_lock(&root->fs_info->ordered_extent_lock);
 359                         continue;
 360                 }
 361
 362                 list_del_init(&ordered->root_extent_list);
 363                 atomic_inc(&ordered->refs);
 364
 365                 /*
 366                  * the inode may be getting freed (in sys_unlink path).
 367                  */
 368                 inode = igrab(ordered->inode);
 369
 370                 spin_unlock(&root->fs_info->ordered_extent_lock);
 371
 372                 if (inode) {
 373                         btrfs_start_ordered_extent(inode, ordered, 1);
 374                         btrfs_put_ordered_extent(ordered);
 375                         iput(inode);
 376                 } else {
 377                         btrfs_put_ordered_extent(ordered);
 378                 }
 379
 380                 spin_lock(&root->fs_info->ordered_extent_lock);
 381         }
 382         spin_unlock(&root->fs_info->ordered_extent_lock);
 383         return 0;
 384 }
 385
 386 /*
 387  * this is used during transaction commit to write all the inodes
 388  * added to the ordered operation list.  These files must be fully on
 389  * disk before the transaction commits.
 390  *
 391  * we have two modes here, one is to just start the IO via filemap_flush
 392  * and the other is to wait for all the io.  When we wait, we have an
 393  * extra check to make sure the ordered operation list really is empty
 394  * before we return
 395  */
 396 int btrfs_run_ordered_operations(struct btrfs_root *root, int wait)
 397 {
 398         struct btrfs_inode *btrfs_inode;
 399         struct inode *inode;
 400         struct list_head splice;
 401
 402         INIT_LIST_HEAD(&splice);
 403
 404         mutex_lock(&root->fs_info->ordered_operations_mutex);
 405         spin_lock(&root->fs_info->ordered_extent_lock);
 406 again:
 407         list_splice_init(&root->fs_info->ordered_operations, &splice);
 408
 409         while (!list_empty(&splice)) {
 410                 btrfs_inode = list_entry(splice.next, struct btrfs_inode,
 411                                    ordered_operations);
 412
 413                 inode = &btrfs_inode->vfs_inode;
 414
 415                 list_del_init(&btrfs_inode->ordered_operations);
 416
 417                 /*
 418                  * the inode may be getting freed (in sys_unlink path).
 419                  */
 420                 inode = igrab(inode);
 421
 422                 if (!wait && inode) {
 423                         list_add_tail(&BTRFS_I(inode)->ordered_operations,
 424                               &root->fs_info->ordered_operations);
 425                 }
 426                 spin_unlock(&root->fs_info->ordered_extent_lock);
 427
 428                 if (inode) {
 429                         if (wait)
 430                                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
 431                         else
 432                                 filemap_flush(inode->i_mapping);
 433                         iput(inode);
 434                 }
 435
 436                 cond_resched();
 437                 spin_lock(&root->fs_info->ordered_extent_lock);
 438         }
 439         if (wait && !list_empty(&root->fs_info->ordered_operations))
 440                 goto again;
 441
 442         spin_unlock(&root->fs_info->ordered_extent_lock);
 443         mutex_unlock(&root->fs_info->ordered_operations_mutex);
 444
 445         return 0;
 446 }
 447
 448 /*
 449  * Used to start IO or wait for a given ordered extent to finish.
 450  *
 451  * If wait is one, this effectively waits on page writeback for all the pages
 452  * in the extent, and it waits on the io completion code to insert
 453  * metadata into the btree corresponding to the extent
 454  */
 455 void btrfs_start_ordered_extent(struct inode *inode,
 456                                        struct btrfs_ordered_extent *entry,
 457                                        int wait)
 458 {
 459         u64 start = entry->file_offset;
 460         u64 end = start + entry->len - 1;
 461
 462         /*
 463          * pages in the range can be dirty, clean or writeback.  We
 464          * start IO on any dirty ones so the wait doesn't stall waiting
 465          * for pdflush to find them
 466          */
 467         filemap_fdatawrite_range(inode->i_mapping, start, end);
 468         if (wait) {
 469                 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 470                                                  &entry->flags));
 471         }
 472 }
 473
 474 /*
 475  * Used to wait on ordered extents across a large range of bytes.
 476  */
 477 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 478 {
 479         u64 end;
 480         u64 orig_end;
 481         u64 wait_end;
 482         struct btrfs_ordered_extent *ordered;
 483         int found;
 484
 485         if (start + len < start) {
 486                 orig_end = INT_LIMIT(loff_t);
 487         } else {
 488                 orig_end = start + len - 1;
 489                 if (orig_end > INT_LIMIT(loff_t))
 490                         orig_end = INT_LIMIT(loff_t);
 491         }
 492         wait_end = orig_end;
 493 again:
 494         /* start IO across the range first to instantiate any delalloc
 495          * extents
 496          */
 497         filemap_fdatawrite_range(inode->i_mapping, start, orig_end);
 498
 499         /* The compression code will leave pages locked but return from
 500          * writepage without setting the page writeback.  Starting again
 501          * with WB_SYNC_ALL will end up waiting for the IO to actually start.
 502          */
 503         filemap_fdatawrite_range(inode->i_mapping, start, orig_end);
 504
 505         filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 506
 507         end = orig_end;
 508         found = 0;
 509         while (1) {
 510                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
 511                 if (!ordered)
 512                         break;
 513                 if (ordered->file_offset > orig_end) {
 514                         btrfs_put_ordered_extent(ordered);
 515                         break;
 516                 }
 517                 if (ordered->file_offset + ordered->len < start) {
 518                         btrfs_put_ordered_extent(ordered);
 519                         break;
 520                 }
 521                 found++;
 522                 btrfs_start_ordered_extent(inode, ordered, 1);
 523                 end = ordered->file_offset;
 524                 btrfs_put_ordered_extent(ordered);
 525                 if (end == 0 || end == start)
 526                         break;
 527                 end--;
 528         }
 529         if (found || test_range_bit(&BTRFS_I(inode)->io_tree, start, orig_end,
 530                            EXTENT_DELALLOC, 0, NULL)) {
 531                 schedule_timeout(1);
 532                 goto again;
 533         }
 534         return 0;
 535 }
 536
 537 /*
 538  * find an ordered extent corresponding to file_offset.  return NULL if
 539  * nothing is found, otherwise take a reference on the extent and return it
 540  */
 541 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
 542                                                          u64 file_offset)
 543 {
 544         struct btrfs_ordered_inode_tree *tree;
 545         struct rb_node *node;
 546         struct btrfs_ordered_extent *entry = NULL;
 547
 548         tree = &BTRFS_I(inode)->ordered_tree;
 549         mutex_lock(&tree->mutex);
 550         node = tree_search(tree, file_offset);
 551         if (!node)
 552                 goto out;
 553
 554         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 555         if (!offset_in_entry(entry, file_offset))
 556                 entry = NULL;
 557         if (entry)
 558                 atomic_inc(&entry->refs);
 559 out:
 560         mutex_unlock(&tree->mutex);
 561         return entry;
 562 }
 563
 564 /*
 565  * lookup and return any extent before 'file_offset'.  NULL is returned
 566  * if none is found
 567  */
 568 struct btrfs_ordered_extent *
 569 btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
 570 {
 571         struct btrfs_ordered_inode_tree *tree;
 572         struct rb_node *node;
 573         struct btrfs_ordered_extent *entry = NULL;
 574
 575         tree = &BTRFS_I(inode)->ordered_tree;
 576         mutex_lock(&tree->mutex);
 577         node = tree_search(tree, file_offset);
 578         if (!node)
 579                 goto out;
 580
 581         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 582         atomic_inc(&entry->refs);
 583 out:
 584         mutex_unlock(&tree->mutex);
 585         return entry;
 586 }
 587
 588 /*
 589  * After an extent is done, call this to conditionally update the on disk
 590  * i_size.  i_size is updated to cover any fully written part of the file.
 591  */
 592 int btrfs_ordered_update_i_size(struct inode *inode,
 593                                 struct btrfs_ordered_extent *ordered)
 594 {
 595         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 596         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 597         u64 disk_i_size;
 598         u64 new_i_size;
 599         u64 i_size_test;
 600         struct rb_node *node;
 601         struct btrfs_ordered_extent *test;
 602
 603         mutex_lock(&tree->mutex);
 604         disk_i_size = BTRFS_I(inode)->disk_i_size;
 605
 606         /*
 607          * if the disk i_size is already at the inode->i_size, or
 608          * this ordered extent is inside the disk i_size, we're done
 609          */
 610         if (disk_i_size >= inode->i_size ||
 611             ordered->file_offset + ordered->len <= disk_i_size) {
 612                 goto out;
 613         }
 614
 615         /*
 616          * we can't update the disk_isize if there are delalloc bytes
 617          * between disk_i_size and  this ordered extent
 618          */
 619         if (test_range_bit(io_tree, disk_i_size,
 620                            ordered->file_offset + ordered->len - 1,
 621                            EXTENT_DELALLOC, 0, NULL)) {
 622                 goto out;
 623         }
 624         /*
 625          * walk backward from this ordered extent to disk_i_size.
 626          * if we find an ordered extent then we can't update disk i_size
 627          * yet
 628          */
 629         node = &ordered->rb_node;
 630         while (1) {
 631                 node = rb_prev(node);
 632                 if (!node)
 633                         break;
 634                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 635                 if (test->file_offset + test->len <= disk_i_size)
 636                         break;
 637                 if (test->file_offset >= inode->i_size)
 638                         break;
 639                 if (test->file_offset >= disk_i_size)
 640                         goto out;
 641         }
 642         new_i_size = min_t(u64, entry_end(ordered), i_size_read(inode));
 643
 644         /*
 645          * at this point, we know we can safely update i_size to at least
 646          * the offset from this ordered extent.  But, we need to
 647          * walk forward and see if ios from higher up in the file have
 648          * finished.
 649          */
 650         node = rb_next(&ordered->rb_node);
 651         i_size_test = 0;
 652         if (node) {
 653                 /*
 654                  * do we have an area where IO might have finished
 655                  * between our ordered extent and the next one.
 656                  */
 657                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 658                 if (test->file_offset > entry_end(ordered))
 659                         i_size_test = test->file_offset;
 660         } else {
 661                 i_size_test = i_size_read(inode);
 662         }
 663
 664         /*
 665          * i_size_test is the end of a region after this ordered
 666          * extent where there are no ordered extents.  As long as there
 667          * are no delalloc bytes in this area, it is safe to update
 668          * disk_i_size to the end of the region.
 669          */
 670         if (i_size_test > entry_end(ordered) &&
 671             !test_range_bit(io_tree, entry_end(ordered), i_size_test - 1,
 672                            EXTENT_DELALLOC, 0, NULL)) {
 673                 new_i_size = min_t(u64, i_size_test, i_size_read(inode));
 674         }
 675         BTRFS_I(inode)->disk_i_size = new_i_size;
 676 out:
 677         mutex_unlock(&tree->mutex);
 678         return 0;
 679 }
 680
 681 /*
 682  * search the ordered extents for one corresponding to 'offset' and
 683  * try to find a checksum.  This is used because we allow pages to
 684  * be reclaimed before their checksum is actually put into the btree
 685  */
 686 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
 687                            u32 *sum)
 688 {
 689         struct btrfs_ordered_sum *ordered_sum;
 690         struct btrfs_sector_sum *sector_sums;
 691         struct btrfs_ordered_extent *ordered;
 692         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 693         unsigned long num_sectors;
 694         unsigned long i;
 695         u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
 696         int ret = 1;
 697
 698         ordered = btrfs_lookup_ordered_extent(inode, offset);
 699         if (!ordered)
 700                 return 1;
 701
 702         mutex_lock(&tree->mutex);
 703         list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
 704                 if (disk_bytenr >= ordered_sum->bytenr) {
 705                         num_sectors = ordered_sum->len / sectorsize;
 706                         sector_sums = ordered_sum->sums;
 707                         for (i = 0; i < num_sectors; i++) {
 708                                 if (sector_sums[i].bytenr == disk_bytenr) {
 709                                         *sum = sector_sums[i].sum;
 710                                         ret = 0;
 711                                         goto out;
 712                                 }
 713                         }
 714                 }
 715         }
 716 out:
 717         mutex_unlock(&tree->mutex);
 718         btrfs_put_ordered_extent(ordered);
 719         return ret;
 720 }
 721
 722
 723 /*
 724  * add a given inode to the list of inodes that must be fully on
 725  * disk before a transaction commit finishes.
 726  *
 727  * This basically gives us the ext3 style data=ordered mode, and it is mostly
 728  * used to make sure renamed files are fully on disk.
 729  *
 730  * It is a noop if the inode is already fully on disk.
 731  *
 732  * If trans is not null, we'll do a friendly check for a transaction that
 733  * is already flushing things and force the IO down ourselves.
 734  */
 735 int btrfs_add_ordered_operation(struct btrfs_trans_handle *trans,
 736                                 struct btrfs_root *root,
 737                                 struct inode *inode)
 738 {
 739         u64 last_mod;
 740
 741         last_mod = max(BTRFS_I(inode)->generation, BTRFS_I(inode)->last_trans);
 742
 743         /*
 744          * if this file hasn't been changed since the last transaction
 745          * commit, we can safely return without doing anything
 746          */
 747         if (last_mod < root->fs_info->last_trans_committed)
 748                 return 0;
 749
 750         /*
 751          * the transaction is already committing.  Just start the IO and
 752          * don't bother with all of this list nonsense
 753          */
 754         if (trans && root->fs_info->running_transaction->blocked) {
 755                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
 756                 return 0;
 757         }
 758
 759         spin_lock(&root->fs_info->ordered_extent_lock);
 760         if (list_empty(&BTRFS_I(inode)->ordered_operations)) {
 761                 list_add_tail(&BTRFS_I(inode)->ordered_operations,
 762                               &root->fs_info->ordered_operations);
 763         }
 764         spin_unlock(&root->fs_info->ordered_extent_lock);
 765
 766         return 0;
 767 }