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/slab.h>
  20 #include <linux/blkdev.h>
  21 #include <linux/writeback.h>
  22 #include <linux/pagevec.h>
  23 #include "ctree.h"
  24 #include "transaction.h"
  25 #include "btrfs_inode.h"
  26 #include "extent_io.h"
  27
  28 static u64 entry_end(struct btrfs_ordered_extent *entry)
  29 {
  30         if (entry->file_offset + entry->len < entry->file_offset)
  31                 return (u64)-1;
  32         return entry->file_offset + entry->len;
  33 }
  34
  35 /* returns NULL if the insertion worked, or it returns the node it did find
  36  * in the tree
  37  */
  38 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  39                                    struct rb_node *node)
  40 {
  41         struct rb_node **p = &root->rb_node;
  42         struct rb_node *parent = NULL;
  43         struct btrfs_ordered_extent *entry;
  44
  45         while (*p) {
  46                 parent = *p;
  47                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  48
  49                 if (file_offset < entry->file_offset)
  50                         p = &(*p)->rb_left;
  51                 else if (file_offset >= entry_end(entry))
  52                         p = &(*p)->rb_right;
  53                 else
  54                         return parent;
  55         }
  56
  57         rb_link_node(node, parent, p);
  58         rb_insert_color(node, root);
  59         return NULL;
  60 }
  61
  62 /*
  63  * look for a given offset in the tree, and if it can't be found return the
  64  * first lesser offset
  65  */
  66 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  67                                      struct rb_node **prev_ret)
  68 {
  69         struct rb_node *n = root->rb_node;
  70         struct rb_node *prev = NULL;
  71         struct rb_node *test;
  72         struct btrfs_ordered_extent *entry;
  73         struct btrfs_ordered_extent *prev_entry = NULL;
  74
  75         while (n) {
  76                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  77                 prev = n;
  78                 prev_entry = entry;
  79
  80                 if (file_offset < entry->file_offset)
  81                         n = n->rb_left;
  82                 else if (file_offset >= entry_end(entry))
  83                         n = n->rb_right;
  84                 else
  85                         return n;
  86         }
  87         if (!prev_ret)
  88                 return NULL;
  89
  90         while (prev && file_offset >= entry_end(prev_entry)) {
  91                 test = rb_next(prev);
  92                 if (!test)
  93                         break;
  94                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
  95                                       rb_node);
  96                 if (file_offset < entry_end(prev_entry))
  97                         break;
  98
  99                 prev = test;
 100         }
 101         if (prev)
 102                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
 103                                       rb_node);
 104         while (prev && file_offset < entry_end(prev_entry)) {
 105                 test = rb_prev(prev);
 106                 if (!test)
 107                         break;
 108                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 109                                       rb_node);
 110                 prev = test;
 111         }
 112         *prev_ret = prev;
 113         return NULL;
 114 }
 115
 116 /*
 117  * helper to check if a given offset is inside a given entry
 118  */
 119 static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
 120 {
 121         if (file_offset < entry->file_offset ||
 122             entry->file_offset + entry->len <= file_offset)
 123                 return 0;
 124         return 1;
 125 }
 126
 127 /*
 128  * look find the first ordered struct that has this offset, otherwise
 129  * the first one less than this offset
 130  */
 131 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 132                                           u64 file_offset)
 133 {
 134         struct rb_root *root = &tree->tree;
 135         struct rb_node *prev;
 136         struct rb_node *ret;
 137         struct btrfs_ordered_extent *entry;
 138
 139         if (tree->last) {
 140                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 141                                  rb_node);
 142                 if (offset_in_entry(entry, file_offset))
 143                         return tree->last;
 144         }
 145         ret = __tree_search(root, file_offset, &prev);
 146         if (!ret)
 147                 ret = prev;
 148         if (ret)
 149                 tree->last = ret;
 150         return ret;
 151 }
 152
 153 /* allocate and add a new ordered_extent into the per-inode tree.
 154  * file_offset is the logical offset in the file
 155  *
 156  * start is the disk block number of an extent already reserved in the
 157  * extent allocation tree
 158  *
 159  * len is the length of the extent
 160  *
 161  * The tree is given a single reference on the ordered extent that was
 162  * inserted.
 163  */
 164 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 165                              u64 start, u64 len, u64 disk_len, int type)
 166 {
 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 = kzalloc(sizeof(*entry), GFP_NOFS);
 173         if (!entry)
 174                 return -ENOMEM;
 175
 176         entry->file_offset = file_offset;
 177         entry->start = start;
 178         entry->len = len;
 179         entry->disk_len = disk_len;
 180         entry->bytes_left = len;
 181         entry->inode = inode;
 182         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 183                 set_bit(type, &entry->flags);
 184
 185         /* one ref for the tree */
 186         atomic_set(&entry->refs, 1);
 187         init_waitqueue_head(&entry->wait);
 188         INIT_LIST_HEAD(&entry->list);
 189         INIT_LIST_HEAD(&entry->root_extent_list);
 190
 191         spin_lock(&tree->lock);
 192         node = tree_insert(&tree->tree, file_offset,
 193                            &entry->rb_node);
 194         BUG_ON(node);
 195         spin_unlock(&tree->lock);
 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         BUG_ON(node);
 203         return 0;
 204 }
 205
 206 /*
 207  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 208  * when an ordered extent is finished.  If the list covers more than one
 209  * ordered extent, it is split across multiples.
 210  */
 211 int btrfs_add_ordered_sum(struct inode *inode,
 212                           struct btrfs_ordered_extent *entry,
 213                           struct btrfs_ordered_sum *sum)
 214 {
 215         struct btrfs_ordered_inode_tree *tree;
 216
 217         tree = &BTRFS_I(inode)->ordered_tree;
 218         spin_lock(&tree->lock);
 219         list_add_tail(&sum->list, &entry->list);
 220         spin_unlock(&tree->lock);
 221         return 0;
 222 }
 223
 224 /*
 225  * this is used to account for finished IO across a given range
 226  * of the file.  The IO should not span ordered extents.  If
 227  * a given ordered_extent is completely done, 1 is returned, otherwise
 228  * 0.
 229  *
 230  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 231  * to make sure this function only returns 1 once for a given ordered extent.
 232  */
 233 int btrfs_dec_test_ordered_pending(struct inode *inode,
 234                                    struct btrfs_ordered_extent **cached,
 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 = NULL;
 240         int ret;
 241
 242         tree = &BTRFS_I(inode)->ordered_tree;
 243         spin_lock(&tree->lock);
 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         if (!ret && cached && entry) {
 268                 *cached = entry;
 269                 atomic_inc(&entry->refs);
 270         }
 271         spin_unlock(&tree->lock);
 272         return ret == 0;
 273 }
 274
 275 /*
 276  * used to drop a reference on an ordered extent.  This will free
 277  * the extent if the last reference is dropped
 278  */
 279 int btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 280 {
 281         struct list_head *cur;
 282         struct btrfs_ordered_sum *sum;
 283
 284         if (atomic_dec_and_test(&entry->refs)) {
 285                 while (!list_empty(&entry->list)) {
 286                         cur = entry->list.next;
 287                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 288                         list_del(&sum->list);
 289                         kfree(sum);
 290                 }
 291                 kfree(entry);
 292         }
 293         return 0;
 294 }
 295
 296 /*
 297  * remove an ordered extent from the tree.  No references are dropped
 298  * and you must wake_up entry->wait.  You must hold the tree lock
 299  * while you call this function.
 300  */
 301 static int __btrfs_remove_ordered_extent(struct inode *inode,
 302                                 struct btrfs_ordered_extent *entry)
 303 {
 304         struct btrfs_ordered_inode_tree *tree;
 305         struct btrfs_root *root = BTRFS_I(inode)->root;
 306         struct rb_node *node;
 307
 308         tree = &BTRFS_I(inode)->ordered_tree;
 309         node = &entry->rb_node;
 310         rb_erase(node, &tree->tree);
 311         tree->last = NULL;
 312         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 313
 314         spin_lock(&BTRFS_I(inode)->accounting_lock);
 315         WARN_ON(!BTRFS_I(inode)->outstanding_extents);
 316         BTRFS_I(inode)->outstanding_extents--;
 317         spin_unlock(&BTRFS_I(inode)->accounting_lock);
 318         btrfs_unreserve_metadata_for_delalloc(BTRFS_I(inode)->root,
 319                                               inode, 1);
 320
 321         spin_lock(&root->fs_info->ordered_extent_lock);
 322         list_del_init(&entry->root_extent_list);
 323
 324         /*
 325          * we have no more ordered extents for this inode and
 326          * no dirty pages.  We can safely remove it from the
 327          * list of ordered extents
 328          */
 329         if (RB_EMPTY_ROOT(&tree->tree) &&
 330             !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) {
 331                 list_del_init(&BTRFS_I(inode)->ordered_operations);
 332         }
 333         spin_unlock(&root->fs_info->ordered_extent_lock);
 334
 335         return 0;
 336 }
 337
 338 /*
 339  * remove an ordered extent from the tree.  No references are dropped
 340  * but any waiters are woken.
 341  */
 342 int btrfs_remove_ordered_extent(struct inode *inode,
 343                                 struct btrfs_ordered_extent *entry)
 344 {
 345         struct btrfs_ordered_inode_tree *tree;
 346         int ret;
 347
 348         tree = &BTRFS_I(inode)->ordered_tree;
 349         spin_lock(&tree->lock);
 350         ret = __btrfs_remove_ordered_extent(inode, entry);
 351         spin_unlock(&tree->lock);
 352         wake_up(&entry->wait);
 353
 354         return ret;
 355 }
 356
 357 /*
 358  * wait for all the ordered extents in a root.  This is done when balancing
 359  * space between drives.
 360  */
 361 int btrfs_wait_ordered_extents(struct btrfs_root *root,
 362                                int nocow_only, int delay_iput)
 363 {
 364         struct list_head splice;
 365         struct list_head *cur;
 366         struct btrfs_ordered_extent *ordered;
 367         struct inode *inode;
 368
 369         INIT_LIST_HEAD(&splice);
 370
 371         spin_lock(&root->fs_info->ordered_extent_lock);
 372         list_splice_init(&root->fs_info->ordered_extents, &splice);
 373         while (!list_empty(&splice)) {
 374                 cur = splice.next;
 375                 ordered = list_entry(cur, struct btrfs_ordered_extent,
 376                                      root_extent_list);
 377                 if (nocow_only &&
 378                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags) &&
 379                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags)) {
 380                         list_move(&ordered->root_extent_list,
 381                                   &root->fs_info->ordered_extents);
 382                         cond_resched_lock(&root->fs_info->ordered_extent_lock);
 383                         continue;
 384                 }
 385
 386                 list_del_init(&ordered->root_extent_list);
 387                 atomic_inc(&ordered->refs);
 388
 389                 /*
 390                  * the inode may be getting freed (in sys_unlink path).
 391                  */
 392                 inode = igrab(ordered->inode);
 393
 394                 spin_unlock(&root->fs_info->ordered_extent_lock);
 395
 396                 if (inode) {
 397                         btrfs_start_ordered_extent(inode, ordered, 1);
 398                         btrfs_put_ordered_extent(ordered);
 399                         if (delay_iput)
 400                                 btrfs_add_delayed_iput(inode);
 401                         else
 402                                 iput(inode);
 403                 } else {
 404                         btrfs_put_ordered_extent(ordered);
 405                 }
 406
 407                 spin_lock(&root->fs_info->ordered_extent_lock);
 408         }
 409         spin_unlock(&root->fs_info->ordered_extent_lock);
 410         return 0;
 411 }
 412
 413 /*
 414  * this is used during transaction commit to write all the inodes
 415  * added to the ordered operation list.  These files must be fully on
 416  * disk before the transaction commits.
 417  *
 418  * we have two modes here, one is to just start the IO via filemap_flush
 419  * and the other is to wait for all the io.  When we wait, we have an
 420  * extra check to make sure the ordered operation list really is empty
 421  * before we return
 422  */
 423 int btrfs_run_ordered_operations(struct btrfs_root *root, int wait)
 424 {
 425         struct btrfs_inode *btrfs_inode;
 426         struct inode *inode;
 427         struct list_head splice;
 428
 429         INIT_LIST_HEAD(&splice);
 430
 431         mutex_lock(&root->fs_info->ordered_operations_mutex);
 432         spin_lock(&root->fs_info->ordered_extent_lock);
 433 again:
 434         list_splice_init(&root->fs_info->ordered_operations, &splice);
 435
 436         while (!list_empty(&splice)) {
 437                 btrfs_inode = list_entry(splice.next, struct btrfs_inode,
 438                                    ordered_operations);
 439
 440                 inode = &btrfs_inode->vfs_inode;
 441
 442                 list_del_init(&btrfs_inode->ordered_operations);
 443
 444                 /*
 445                  * the inode may be getting freed (in sys_unlink path).
 446                  */
 447                 inode = igrab(inode);
 448
 449                 if (!wait && inode) {
 450                         list_add_tail(&BTRFS_I(inode)->ordered_operations,
 451                               &root->fs_info->ordered_operations);
 452                 }
 453                 spin_unlock(&root->fs_info->ordered_extent_lock);
 454
 455                 if (inode) {
 456                         if (wait)
 457                                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
 458                         else
 459                                 filemap_flush(inode->i_mapping);
 460                         btrfs_add_delayed_iput(inode);
 461                 }
 462
 463                 cond_resched();
 464                 spin_lock(&root->fs_info->ordered_extent_lock);
 465         }
 466         if (wait && !list_empty(&root->fs_info->ordered_operations))
 467                 goto again;
 468
 469         spin_unlock(&root->fs_info->ordered_extent_lock);
 470         mutex_unlock(&root->fs_info->ordered_operations_mutex);
 471
 472         return 0;
 473 }
 474
 475 /*
 476  * Used to start IO or wait for a given ordered extent to finish.
 477  *
 478  * If wait is one, this effectively waits on page writeback for all the pages
 479  * in the extent, and it waits on the io completion code to insert
 480  * metadata into the btree corresponding to the extent
 481  */
 482 void btrfs_start_ordered_extent(struct inode *inode,
 483                                        struct btrfs_ordered_extent *entry,
 484                                        int wait)
 485 {
 486         u64 start = entry->file_offset;
 487         u64 end = start + entry->len - 1;
 488
 489         /*
 490          * pages in the range can be dirty, clean or writeback.  We
 491          * start IO on any dirty ones so the wait doesn't stall waiting
 492          * for pdflush to find them
 493          */
 494         filemap_fdatawrite_range(inode->i_mapping, start, end);
 495         if (wait) {
 496                 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 497                                                  &entry->flags));
 498         }
 499 }
 500
 501 /*
 502  * Used to wait on ordered extents across a large range of bytes.
 503  */
 504 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 505 {
 506         u64 end;
 507         u64 orig_end;
 508         u64 wait_end;
 509         struct btrfs_ordered_extent *ordered;
 510         int found;
 511
 512         if (start + len < start) {
 513                 orig_end = INT_LIMIT(loff_t);
 514         } else {
 515                 orig_end = start + len - 1;
 516                 if (orig_end > INT_LIMIT(loff_t))
 517                         orig_end = INT_LIMIT(loff_t);
 518         }
 519         wait_end = orig_end;
 520 again:
 521         /* start IO across the range first to instantiate any delalloc
 522          * extents
 523          */
 524         filemap_fdatawrite_range(inode->i_mapping, start, orig_end);
 525
 526         /* The compression code will leave pages locked but return from
 527          * writepage without setting the page writeback.  Starting again
 528          * with WB_SYNC_ALL will end up waiting for the IO to actually start.
 529          */
 530         filemap_fdatawrite_range(inode->i_mapping, start, orig_end);
 531
 532         filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 533
 534         end = orig_end;
 535         found = 0;
 536         while (1) {
 537                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
 538                 if (!ordered)
 539                         break;
 540                 if (ordered->file_offset > orig_end) {
 541                         btrfs_put_ordered_extent(ordered);
 542                         break;
 543                 }
 544                 if (ordered->file_offset + ordered->len < start) {
 545                         btrfs_put_ordered_extent(ordered);
 546                         break;
 547                 }
 548                 found++;
 549                 btrfs_start_ordered_extent(inode, ordered, 1);
 550                 end = ordered->file_offset;
 551                 btrfs_put_ordered_extent(ordered);
 552                 if (end == 0 || end == start)
 553                         break;
 554                 end--;
 555         }
 556         if (found || test_range_bit(&BTRFS_I(inode)->io_tree, start, orig_end,
 557                            EXTENT_DELALLOC, 0, NULL)) {
 558                 schedule_timeout(1);
 559                 goto again;
 560         }
 561         return 0;
 562 }
 563
 564 /*
 565  * find an ordered extent corresponding to file_offset.  return NULL if
 566  * nothing is found, otherwise take a reference on the extent and return it
 567  */
 568 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
 569                                                          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         spin_lock(&tree->lock);
 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         if (!offset_in_entry(entry, file_offset))
 583                 entry = NULL;
 584         if (entry)
 585                 atomic_inc(&entry->refs);
 586 out:
 587         spin_unlock(&tree->lock);
 588         return entry;
 589 }
 590
 591 /*
 592  * lookup and return any extent before 'file_offset'.  NULL is returned
 593  * if none is found
 594  */
 595 struct btrfs_ordered_extent *
 596 btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
 597 {
 598         struct btrfs_ordered_inode_tree *tree;
 599         struct rb_node *node;
 600         struct btrfs_ordered_extent *entry = NULL;
 601
 602         tree = &BTRFS_I(inode)->ordered_tree;
 603         spin_lock(&tree->lock);
 604         node = tree_search(tree, file_offset);
 605         if (!node)
 606                 goto out;
 607
 608         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 609         atomic_inc(&entry->refs);
 610 out:
 611         spin_unlock(&tree->lock);
 612         return entry;
 613 }
 614
 615 /*
 616  * After an extent is done, call this to conditionally update the on disk
 617  * i_size.  i_size is updated to cover any fully written part of the file.
 618  */
 619 int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
 620                                 struct btrfs_ordered_extent *ordered)
 621 {
 622         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 623         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 624         u64 disk_i_size;
 625         u64 new_i_size;
 626         u64 i_size_test;
 627         u64 i_size = i_size_read(inode);
 628         struct rb_node *node;
 629         struct rb_node *prev = NULL;
 630         struct btrfs_ordered_extent *test;
 631         int ret = 1;
 632
 633         if (ordered)
 634                 offset = entry_end(ordered);
 635         else
 636                 offset = ALIGN(offset, BTRFS_I(inode)->root->sectorsize);
 637
 638         spin_lock(&tree->lock);
 639         disk_i_size = BTRFS_I(inode)->disk_i_size;
 640
 641         /* truncate file */
 642         if (disk_i_size > i_size) {
 643                 BTRFS_I(inode)->disk_i_size = i_size;
 644                 ret = 0;
 645                 goto out;
 646         }
 647
 648         /*
 649          * if the disk i_size is already at the inode->i_size, or
 650          * this ordered extent is inside the disk i_size, we're done
 651          */
 652         if (disk_i_size == i_size || offset <= disk_i_size) {
 653                 goto out;
 654         }
 655
 656         /*
 657          * we can't update the disk_isize if there are delalloc bytes
 658          * between disk_i_size and  this ordered extent
 659          */
 660         if (test_range_bit(io_tree, disk_i_size, offset - 1,
 661                            EXTENT_DELALLOC, 0, NULL)) {
 662                 goto out;
 663         }
 664         /*
 665          * walk backward from this ordered extent to disk_i_size.
 666          * if we find an ordered extent then we can't update disk i_size
 667          * yet
 668          */
 669         if (ordered) {
 670                 node = rb_prev(&ordered->rb_node);
 671         } else {
 672                 prev = tree_search(tree, offset);
 673                 /*
 674                  * we insert file extents without involving ordered struct,
 675                  * so there should be no ordered struct cover this offset
 676                  */
 677                 if (prev) {
 678                         test = rb_entry(prev, struct btrfs_ordered_extent,
 679                                         rb_node);
 680                         BUG_ON(offset_in_entry(test, offset));
 681                 }
 682                 node = prev;
 683         }
 684         while (node) {
 685                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 686                 if (test->file_offset + test->len <= disk_i_size)
 687                         break;
 688                 if (test->file_offset >= i_size)
 689                         break;
 690                 if (test->file_offset >= disk_i_size)
 691                         goto out;
 692                 node = rb_prev(node);
 693         }
 694         new_i_size = min_t(u64, offset, i_size);
 695
 696         /*
 697          * at this point, we know we can safely update i_size to at least
 698          * the offset from this ordered extent.  But, we need to
 699          * walk forward and see if ios from higher up in the file have
 700          * finished.
 701          */
 702         if (ordered) {
 703                 node = rb_next(&ordered->rb_node);
 704         } else {
 705                 if (prev)
 706                         node = rb_next(prev);
 707                 else
 708                         node = rb_first(&tree->tree);
 709         }
 710         i_size_test = 0;
 711         if (node) {
 712                 /*
 713                  * do we have an area where IO might have finished
 714                  * between our ordered extent and the next one.
 715                  */
 716                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 717                 if (test->file_offset > offset)
 718                         i_size_test = test->file_offset;
 719         } else {
 720                 i_size_test = i_size;
 721         }
 722
 723         /*
 724          * i_size_test is the end of a region after this ordered
 725          * extent where there are no ordered extents.  As long as there
 726          * are no delalloc bytes in this area, it is safe to update
 727          * disk_i_size to the end of the region.
 728          */
 729         if (i_size_test > offset &&
 730             !test_range_bit(io_tree, offset, i_size_test - 1,
 731                             EXTENT_DELALLOC, 0, NULL)) {
 732                 new_i_size = min_t(u64, i_size_test, i_size);
 733         }
 734         BTRFS_I(inode)->disk_i_size = new_i_size;
 735         ret = 0;
 736 out:
 737         /*
 738          * we need to remove the ordered extent with the tree lock held
 739          * so that other people calling this function don't find our fully
 740          * processed ordered entry and skip updating the i_size
 741          */
 742         if (ordered)
 743                 __btrfs_remove_ordered_extent(inode, ordered);
 744         spin_unlock(&tree->lock);
 745         if (ordered)
 746                 wake_up(&ordered->wait);
 747         return ret;
 748 }
 749
 750 /*
 751  * search the ordered extents for one corresponding to 'offset' and
 752  * try to find a checksum.  This is used because we allow pages to
 753  * be reclaimed before their checksum is actually put into the btree
 754  */
 755 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
 756                            u32 *sum)
 757 {
 758         struct btrfs_ordered_sum *ordered_sum;
 759         struct btrfs_sector_sum *sector_sums;
 760         struct btrfs_ordered_extent *ordered;
 761         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 762         unsigned long num_sectors;
 763         unsigned long i;
 764         u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
 765         int ret = 1;
 766
 767         ordered = btrfs_lookup_ordered_extent(inode, offset);
 768         if (!ordered)
 769                 return 1;
 770
 771         spin_lock(&tree->lock);
 772         list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
 773                 if (disk_bytenr >= ordered_sum->bytenr) {
 774                         num_sectors = ordered_sum->len / sectorsize;
 775                         sector_sums = ordered_sum->sums;
 776                         for (i = 0; i < num_sectors; i++) {
 777                                 if (sector_sums[i].bytenr == disk_bytenr) {
 778                                         *sum = sector_sums[i].sum;
 779                                         ret = 0;
 780                                         goto out;
 781                                 }
 782                         }
 783                 }
 784         }
 785 out:
 786         spin_unlock(&tree->lock);
 787         btrfs_put_ordered_extent(ordered);
 788         return ret;
 789 }
 790
 791
 792 /*
 793  * add a given inode to the list of inodes that must be fully on
 794  * disk before a transaction commit finishes.
 795  *
 796  * This basically gives us the ext3 style data=ordered mode, and it is mostly
 797  * used to make sure renamed files are fully on disk.
 798  *
 799  * It is a noop if the inode is already fully on disk.
 800  *
 801  * If trans is not null, we'll do a friendly check for a transaction that
 802  * is already flushing things and force the IO down ourselves.
 803  */
 804 int btrfs_add_ordered_operation(struct btrfs_trans_handle *trans,
 805                                 struct btrfs_root *root,
 806                                 struct inode *inode)
 807 {
 808         u64 last_mod;
 809
 810         last_mod = max(BTRFS_I(inode)->generation, BTRFS_I(inode)->last_trans);
 811
 812         /*
 813          * if this file hasn't been changed since the last transaction
 814          * commit, we can safely return without doing anything
 815          */
 816         if (last_mod < root->fs_info->last_trans_committed)
 817                 return 0;
 818
 819         /*
 820          * the transaction is already committing.  Just start the IO and
 821          * don't bother with all of this list nonsense
 822          */
 823         if (trans && root->fs_info->running_transaction->blocked) {
 824                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
 825                 return 0;
 826         }
 827
 828         spin_lock(&root->fs_info->ordered_extent_lock);
 829         if (list_empty(&BTRFS_I(inode)->ordered_operations)) {
 830                 list_add_tail(&BTRFS_I(inode)->ordered_operations,
 831                               &root->fs_info->ordered_operations);
 832         }
 833         spin_unlock(&root->fs_info->ordered_extent_lock);
 834
 835         return 0;
 836 }