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 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 128                           u64 len)
 129 {
 130         if (file_offset + len <= entry->file_offset ||
 131             entry->file_offset + entry->len <= file_offset)
 132                 return 0;
 133         return 1;
 134 }
 135
 136 /*
 137  * look find the first ordered struct that has this offset, otherwise
 138  * the first one less than this offset
 139  */
 140 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 141                                           u64 file_offset)
 142 {
 143         struct rb_root *root = &tree->tree;
 144         struct rb_node *prev = NULL;
 145         struct rb_node *ret;
 146         struct btrfs_ordered_extent *entry;
 147
 148         if (tree->last) {
 149                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 150                                  rb_node);
 151                 if (offset_in_entry(entry, file_offset))
 152                         return tree->last;
 153         }
 154         ret = __tree_search(root, file_offset, &prev);
 155         if (!ret)
 156                 ret = prev;
 157         if (ret)
 158                 tree->last = ret;
 159         return ret;
 160 }
 161
 162 /* allocate and add a new ordered_extent into the per-inode tree.
 163  * file_offset is the logical offset in the file
 164  *
 165  * start is the disk block number of an extent already reserved in the
 166  * extent allocation tree
 167  *
 168  * len is the length of the extent
 169  *
 170  * The tree is given a single reference on the ordered extent that was
 171  * inserted.
 172  */
 173 static int __btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 174                                       u64 start, u64 len, u64 disk_len,
 175                                       int type, int dio, int compress_type)
 176 {
 177         struct btrfs_ordered_inode_tree *tree;
 178         struct rb_node *node;
 179         struct btrfs_ordered_extent *entry;
 180
 181         tree = &BTRFS_I(inode)->ordered_tree;
 182         entry = kzalloc(sizeof(*entry), GFP_NOFS);
 183         if (!entry)
 184                 return -ENOMEM;
 185
 186         entry->file_offset = file_offset;
 187         entry->start = start;
 188         entry->len = len;
 189         entry->disk_len = disk_len;
 190         entry->bytes_left = len;
 191         entry->inode = inode;
 192         entry->compress_type = compress_type;
 193         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 194                 set_bit(type, &entry->flags);
 195
 196         if (dio)
 197                 set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
 198
 199         /* one ref for the tree */
 200         atomic_set(&entry->refs, 1);
 201         init_waitqueue_head(&entry->wait);
 202         INIT_LIST_HEAD(&entry->list);
 203         INIT_LIST_HEAD(&entry->root_extent_list);
 204
 205         trace_btrfs_ordered_extent_add(inode, entry);
 206
 207         spin_lock(&tree->lock);
 208         node = tree_insert(&tree->tree, file_offset,
 209                            &entry->rb_node);
 210         BUG_ON(node);
 211         spin_unlock(&tree->lock);
 212
 213         spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
 214         list_add_tail(&entry->root_extent_list,
 215                       &BTRFS_I(inode)->root->fs_info->ordered_extents);
 216         spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
 217
 218         BUG_ON(node);
 219         return 0;
 220 }
 221
 222 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 223                              u64 start, u64 len, u64 disk_len, int type)
 224 {
 225         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 226                                           disk_len, type, 0,
 227                                           BTRFS_COMPRESS_NONE);
 228 }
 229
 230 int btrfs_add_ordered_extent_dio(struct inode *inode, u64 file_offset,
 231                                  u64 start, u64 len, u64 disk_len, int type)
 232 {
 233         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 234                                           disk_len, type, 1,
 235                                           BTRFS_COMPRESS_NONE);
 236 }
 237
 238 int btrfs_add_ordered_extent_compress(struct inode *inode, u64 file_offset,
 239                                       u64 start, u64 len, u64 disk_len,
 240                                       int type, int compress_type)
 241 {
 242         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 243                                           disk_len, type, 0,
 244                                           compress_type);
 245 }
 246
 247 /*
 248  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 249  * when an ordered extent is finished.  If the list covers more than one
 250  * ordered extent, it is split across multiples.
 251  */
 252 int btrfs_add_ordered_sum(struct inode *inode,
 253                           struct btrfs_ordered_extent *entry,
 254                           struct btrfs_ordered_sum *sum)
 255 {
 256         struct btrfs_ordered_inode_tree *tree;
 257
 258         tree = &BTRFS_I(inode)->ordered_tree;
 259         spin_lock(&tree->lock);
 260         list_add_tail(&sum->list, &entry->list);
 261         spin_unlock(&tree->lock);
 262         return 0;
 263 }
 264
 265 /*
 266  * this is used to account for finished IO across a given range
 267  * of the file.  The IO may span ordered extents.  If
 268  * a given ordered_extent is completely done, 1 is returned, otherwise
 269  * 0.
 270  *
 271  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 272  * to make sure this function only returns 1 once for a given ordered extent.
 273  *
 274  * file_offset is updated to one byte past the range that is recorded as
 275  * complete.  This allows you to walk forward in the file.
 276  */
 277 int btrfs_dec_test_first_ordered_pending(struct inode *inode,
 278                                    struct btrfs_ordered_extent **cached,
 279                                    u64 *file_offset, u64 io_size)
 280 {
 281         struct btrfs_ordered_inode_tree *tree;
 282         struct rb_node *node;
 283         struct btrfs_ordered_extent *entry = NULL;
 284         int ret;
 285         u64 dec_end;
 286         u64 dec_start;
 287         u64 to_dec;
 288
 289         tree = &BTRFS_I(inode)->ordered_tree;
 290         spin_lock(&tree->lock);
 291         node = tree_search(tree, *file_offset);
 292         if (!node) {
 293                 ret = 1;
 294                 goto out;
 295         }
 296
 297         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 298         if (!offset_in_entry(entry, *file_offset)) {
 299                 ret = 1;
 300                 goto out;
 301         }
 302
 303         dec_start = max(*file_offset, entry->file_offset);
 304         dec_end = min(*file_offset + io_size, entry->file_offset +
 305                       entry->len);
 306         *file_offset = dec_end;
 307         if (dec_start > dec_end) {
 308                 printk(KERN_CRIT "bad ordering dec_start %llu end %llu\n",
 309                        (unsigned long long)dec_start,
 310                        (unsigned long long)dec_end);
 311         }
 312         to_dec = dec_end - dec_start;
 313         if (to_dec > entry->bytes_left) {
 314                 printk(KERN_CRIT "bad ordered accounting left %llu size %llu\n",
 315                        (unsigned long long)entry->bytes_left,
 316                        (unsigned long long)to_dec);
 317         }
 318         entry->bytes_left -= to_dec;
 319         if (entry->bytes_left == 0)
 320                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 321         else
 322                 ret = 1;
 323 out:
 324         if (!ret && cached && entry) {
 325                 *cached = entry;
 326                 atomic_inc(&entry->refs);
 327         }
 328         spin_unlock(&tree->lock);
 329         return ret == 0;
 330 }
 331
 332 /*
 333  * this is used to account for finished IO across a given range
 334  * of the file.  The IO should not span ordered extents.  If
 335  * a given ordered_extent is completely done, 1 is returned, otherwise
 336  * 0.
 337  *
 338  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 339  * to make sure this function only returns 1 once for a given ordered extent.
 340  */
 341 int btrfs_dec_test_ordered_pending(struct inode *inode,
 342                                    struct btrfs_ordered_extent **cached,
 343                                    u64 file_offset, u64 io_size)
 344 {
 345         struct btrfs_ordered_inode_tree *tree;
 346         struct rb_node *node;
 347         struct btrfs_ordered_extent *entry = NULL;
 348         int ret;
 349
 350         tree = &BTRFS_I(inode)->ordered_tree;
 351         spin_lock(&tree->lock);
 352         node = tree_search(tree, file_offset);
 353         if (!node) {
 354                 ret = 1;
 355                 goto out;
 356         }
 357
 358         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 359         if (!offset_in_entry(entry, file_offset)) {
 360                 ret = 1;
 361                 goto out;
 362         }
 363
 364         if (io_size > entry->bytes_left) {
 365                 printk(KERN_CRIT "bad ordered accounting left %llu size %llu\n",
 366                        (unsigned long long)entry->bytes_left,
 367                        (unsigned long long)io_size);
 368         }
 369         entry->bytes_left -= io_size;
 370         if (entry->bytes_left == 0)
 371                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 372         else
 373                 ret = 1;
 374 out:
 375         if (!ret && cached && entry) {
 376                 *cached = entry;
 377                 atomic_inc(&entry->refs);
 378         }
 379         spin_unlock(&tree->lock);
 380         return ret == 0;
 381 }
 382
 383 /*
 384  * used to drop a reference on an ordered extent.  This will free
 385  * the extent if the last reference is dropped
 386  */
 387 int btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 388 {
 389         struct list_head *cur;
 390         struct btrfs_ordered_sum *sum;
 391
 392         trace_btrfs_ordered_extent_put(entry->inode, entry);
 393
 394         if (atomic_dec_and_test(&entry->refs)) {
 395                 while (!list_empty(&entry->list)) {
 396                         cur = entry->list.next;
 397                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 398                         list_del(&sum->list);
 399                         kfree(sum);
 400                 }
 401                 kfree(entry);
 402         }
 403         return 0;
 404 }
 405
 406 /*
 407  * remove an ordered extent from the tree.  No references are dropped
 408  * and you must wake_up entry->wait.  You must hold the tree lock
 409  * while you call this function.
 410  */
 411 static int __btrfs_remove_ordered_extent(struct inode *inode,
 412                                 struct btrfs_ordered_extent *entry)
 413 {
 414         struct btrfs_ordered_inode_tree *tree;
 415         struct btrfs_root *root = BTRFS_I(inode)->root;
 416         struct rb_node *node;
 417
 418         tree = &BTRFS_I(inode)->ordered_tree;
 419         node = &entry->rb_node;
 420         rb_erase(node, &tree->tree);
 421         tree->last = NULL;
 422         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 423
 424         spin_lock(&root->fs_info->ordered_extent_lock);
 425         list_del_init(&entry->root_extent_list);
 426
 427         trace_btrfs_ordered_extent_remove(inode, entry);
 428
 429         /*
 430          * we have no more ordered extents for this inode and
 431          * no dirty pages.  We can safely remove it from the
 432          * list of ordered extents
 433          */
 434         if (RB_EMPTY_ROOT(&tree->tree) &&
 435             !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) {
 436                 list_del_init(&BTRFS_I(inode)->ordered_operations);
 437         }
 438         spin_unlock(&root->fs_info->ordered_extent_lock);
 439
 440         return 0;
 441 }
 442
 443 /*
 444  * remove an ordered extent from the tree.  No references are dropped
 445  * but any waiters are woken.
 446  */
 447 int btrfs_remove_ordered_extent(struct inode *inode,
 448                                 struct btrfs_ordered_extent *entry)
 449 {
 450         struct btrfs_ordered_inode_tree *tree;
 451         int ret;
 452
 453         tree = &BTRFS_I(inode)->ordered_tree;
 454         spin_lock(&tree->lock);
 455         ret = __btrfs_remove_ordered_extent(inode, entry);
 456         spin_unlock(&tree->lock);
 457         wake_up(&entry->wait);
 458
 459         return ret;
 460 }
 461
 462 /*
 463  * wait for all the ordered extents in a root.  This is done when balancing
 464  * space between drives.
 465  */
 466 int btrfs_wait_ordered_extents(struct btrfs_root *root,
 467                                int nocow_only, int delay_iput)
 468 {
 469         struct list_head splice;
 470         struct list_head *cur;
 471         struct btrfs_ordered_extent *ordered;
 472         struct inode *inode;
 473
 474         INIT_LIST_HEAD(&splice);
 475
 476         spin_lock(&root->fs_info->ordered_extent_lock);
 477         list_splice_init(&root->fs_info->ordered_extents, &splice);
 478         while (!list_empty(&splice)) {
 479                 cur = splice.next;
 480                 ordered = list_entry(cur, struct btrfs_ordered_extent,
 481                                      root_extent_list);
 482                 if (nocow_only &&
 483                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags) &&
 484                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags)) {
 485                         list_move(&ordered->root_extent_list,
 486                                   &root->fs_info->ordered_extents);
 487                         cond_resched_lock(&root->fs_info->ordered_extent_lock);
 488                         continue;
 489                 }
 490
 491                 list_del_init(&ordered->root_extent_list);
 492                 atomic_inc(&ordered->refs);
 493
 494                 /*
 495                  * the inode may be getting freed (in sys_unlink path).
 496                  */
 497                 inode = igrab(ordered->inode);
 498
 499                 spin_unlock(&root->fs_info->ordered_extent_lock);
 500
 501                 if (inode) {
 502                         btrfs_start_ordered_extent(inode, ordered, 1);
 503                         btrfs_put_ordered_extent(ordered);
 504                         if (delay_iput)
 505                                 btrfs_add_delayed_iput(inode);
 506                         else
 507                                 iput(inode);
 508                 } else {
 509                         btrfs_put_ordered_extent(ordered);
 510                 }
 511
 512                 spin_lock(&root->fs_info->ordered_extent_lock);
 513         }
 514         spin_unlock(&root->fs_info->ordered_extent_lock);
 515         return 0;
 516 }
 517
 518 /*
 519  * this is used during transaction commit to write all the inodes
 520  * added to the ordered operation list.  These files must be fully on
 521  * disk before the transaction commits.
 522  *
 523  * we have two modes here, one is to just start the IO via filemap_flush
 524  * and the other is to wait for all the io.  When we wait, we have an
 525  * extra check to make sure the ordered operation list really is empty
 526  * before we return
 527  */
 528 int btrfs_run_ordered_operations(struct btrfs_root *root, int wait)
 529 {
 530         struct btrfs_inode *btrfs_inode;
 531         struct inode *inode;
 532         struct list_head splice;
 533
 534         INIT_LIST_HEAD(&splice);
 535
 536         mutex_lock(&root->fs_info->ordered_operations_mutex);
 537         spin_lock(&root->fs_info->ordered_extent_lock);
 538 again:
 539         list_splice_init(&root->fs_info->ordered_operations, &splice);
 540
 541         while (!list_empty(&splice)) {
 542                 btrfs_inode = list_entry(splice.next, struct btrfs_inode,
 543                                    ordered_operations);
 544
 545                 inode = &btrfs_inode->vfs_inode;
 546
 547                 list_del_init(&btrfs_inode->ordered_operations);
 548
 549                 /*
 550                  * the inode may be getting freed (in sys_unlink path).
 551                  */
 552                 inode = igrab(inode);
 553
 554                 if (!wait && inode) {
 555                         list_add_tail(&BTRFS_I(inode)->ordered_operations,
 556                               &root->fs_info->ordered_operations);
 557                 }
 558                 spin_unlock(&root->fs_info->ordered_extent_lock);
 559
 560                 if (inode) {
 561                         if (wait)
 562                                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
 563                         else
 564                                 filemap_flush(inode->i_mapping);
 565                         btrfs_add_delayed_iput(inode);
 566                 }
 567
 568                 cond_resched();
 569                 spin_lock(&root->fs_info->ordered_extent_lock);
 570         }
 571         if (wait && !list_empty(&root->fs_info->ordered_operations))
 572                 goto again;
 573
 574         spin_unlock(&root->fs_info->ordered_extent_lock);
 575         mutex_unlock(&root->fs_info->ordered_operations_mutex);
 576
 577         return 0;
 578 }
 579
 580 /*
 581  * Used to start IO or wait for a given ordered extent to finish.
 582  *
 583  * If wait is one, this effectively waits on page writeback for all the pages
 584  * in the extent, and it waits on the io completion code to insert
 585  * metadata into the btree corresponding to the extent
 586  */
 587 void btrfs_start_ordered_extent(struct inode *inode,
 588                                        struct btrfs_ordered_extent *entry,
 589                                        int wait)
 590 {
 591         u64 start = entry->file_offset;
 592         u64 end = start + entry->len - 1;
 593
 594         trace_btrfs_ordered_extent_start(inode, entry);
 595
 596         /*
 597          * pages in the range can be dirty, clean or writeback.  We
 598          * start IO on any dirty ones so the wait doesn't stall waiting
 599          * for pdflush to find them
 600          */
 601         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 602                 filemap_fdatawrite_range(inode->i_mapping, start, end);
 603         if (wait) {
 604                 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 605                                                  &entry->flags));
 606         }
 607 }
 608
 609 /*
 610  * Used to wait on ordered extents across a large range of bytes.
 611  */
 612 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 613 {
 614         u64 end;
 615         u64 orig_end;
 616         struct btrfs_ordered_extent *ordered;
 617         int found;
 618
 619         if (start + len < start) {
 620                 orig_end = INT_LIMIT(loff_t);
 621         } else {
 622                 orig_end = start + len - 1;
 623                 if (orig_end > INT_LIMIT(loff_t))
 624                         orig_end = INT_LIMIT(loff_t);
 625         }
 626 again:
 627         /* start IO across the range first to instantiate any delalloc
 628          * extents
 629          */
 630         filemap_fdatawrite_range(inode->i_mapping, start, orig_end);
 631
 632         /* The compression code will leave pages locked but return from
 633          * writepage without setting the page writeback.  Starting again
 634          * with WB_SYNC_ALL will end up waiting for the IO to actually start.
 635          */
 636         filemap_fdatawrite_range(inode->i_mapping, start, orig_end);
 637
 638         filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 639
 640         end = orig_end;
 641         found = 0;
 642         while (1) {
 643                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
 644                 if (!ordered)
 645                         break;
 646                 if (ordered->file_offset > orig_end) {
 647                         btrfs_put_ordered_extent(ordered);
 648                         break;
 649                 }
 650                 if (ordered->file_offset + ordered->len < start) {
 651                         btrfs_put_ordered_extent(ordered);
 652                         break;
 653                 }
 654                 found++;
 655                 btrfs_start_ordered_extent(inode, ordered, 1);
 656                 end = ordered->file_offset;
 657                 btrfs_put_ordered_extent(ordered);
 658                 if (end == 0 || end == start)
 659                         break;
 660                 end--;
 661         }
 662         if (found || test_range_bit(&BTRFS_I(inode)->io_tree, start, orig_end,
 663                            EXTENT_DELALLOC, 0, NULL)) {
 664                 schedule_timeout(1);
 665                 goto again;
 666         }
 667         return 0;
 668 }
 669
 670 /*
 671  * find an ordered extent corresponding to file_offset.  return NULL if
 672  * nothing is found, otherwise take a reference on the extent and return it
 673  */
 674 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
 675                                                          u64 file_offset)
 676 {
 677         struct btrfs_ordered_inode_tree *tree;
 678         struct rb_node *node;
 679         struct btrfs_ordered_extent *entry = NULL;
 680
 681         tree = &BTRFS_I(inode)->ordered_tree;
 682         spin_lock(&tree->lock);
 683         node = tree_search(tree, file_offset);
 684         if (!node)
 685                 goto out;
 686
 687         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 688         if (!offset_in_entry(entry, file_offset))
 689                 entry = NULL;
 690         if (entry)
 691                 atomic_inc(&entry->refs);
 692 out:
 693         spin_unlock(&tree->lock);
 694         return entry;
 695 }
 696
 697 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 698  * extents that exist in the range, rather than just the start of the range.
 699  */
 700 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(struct inode *inode,
 701                                                         u64 file_offset,
 702                                                         u64 len)
 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(&tree->lock);
 710         node = tree_search(tree, file_offset);
 711         if (!node) {
 712                 node = tree_search(tree, file_offset + len);
 713                 if (!node)
 714                         goto out;
 715         }
 716
 717         while (1) {
 718                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 719                 if (range_overlaps(entry, file_offset, len))
 720                         break;
 721
 722                 if (entry->file_offset >= file_offset + len) {
 723                         entry = NULL;
 724                         break;
 725                 }
 726                 entry = NULL;
 727                 node = rb_next(node);
 728                 if (!node)
 729                         break;
 730         }
 731 out:
 732         if (entry)
 733                 atomic_inc(&entry->refs);
 734         spin_unlock(&tree->lock);
 735         return entry;
 736 }
 737
 738 /*
 739  * lookup and return any extent before 'file_offset'.  NULL is returned
 740  * if none is found
 741  */
 742 struct btrfs_ordered_extent *
 743 btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
 744 {
 745         struct btrfs_ordered_inode_tree *tree;
 746         struct rb_node *node;
 747         struct btrfs_ordered_extent *entry = NULL;
 748
 749         tree = &BTRFS_I(inode)->ordered_tree;
 750         spin_lock(&tree->lock);
 751         node = tree_search(tree, file_offset);
 752         if (!node)
 753                 goto out;
 754
 755         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 756         atomic_inc(&entry->refs);
 757 out:
 758         spin_unlock(&tree->lock);
 759         return entry;
 760 }
 761
 762 /*
 763  * After an extent is done, call this to conditionally update the on disk
 764  * i_size.  i_size is updated to cover any fully written part of the file.
 765  */
 766 int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
 767                                 struct btrfs_ordered_extent *ordered)
 768 {
 769         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 770         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
 771         u64 disk_i_size;
 772         u64 new_i_size;
 773         u64 i_size_test;
 774         u64 i_size = i_size_read(inode);
 775         struct rb_node *node;
 776         struct rb_node *prev = NULL;
 777         struct btrfs_ordered_extent *test;
 778         int ret = 1;
 779
 780         if (ordered)
 781                 offset = entry_end(ordered);
 782         else
 783                 offset = ALIGN(offset, BTRFS_I(inode)->root->sectorsize);
 784
 785         spin_lock(&tree->lock);
 786         disk_i_size = BTRFS_I(inode)->disk_i_size;
 787
 788         /* truncate file */
 789         if (disk_i_size > i_size) {
 790                 BTRFS_I(inode)->disk_i_size = i_size;
 791                 ret = 0;
 792                 goto out;
 793         }
 794
 795         /*
 796          * if the disk i_size is already at the inode->i_size, or
 797          * this ordered extent is inside the disk i_size, we're done
 798          */
 799         if (disk_i_size == i_size || offset <= disk_i_size) {
 800                 goto out;
 801         }
 802
 803         /*
 804          * we can't update the disk_isize if there are delalloc bytes
 805          * between disk_i_size and  this ordered extent
 806          */
 807         if (test_range_bit(io_tree, disk_i_size, offset - 1,
 808                            EXTENT_DELALLOC, 0, NULL)) {
 809                 goto out;
 810         }
 811         /*
 812          * walk backward from this ordered extent to disk_i_size.
 813          * if we find an ordered extent then we can't update disk i_size
 814          * yet
 815          */
 816         if (ordered) {
 817                 node = rb_prev(&ordered->rb_node);
 818         } else {
 819                 prev = tree_search(tree, offset);
 820                 /*
 821                  * we insert file extents without involving ordered struct,
 822                  * so there should be no ordered struct cover this offset
 823                  */
 824                 if (prev) {
 825                         test = rb_entry(prev, struct btrfs_ordered_extent,
 826                                         rb_node);
 827                         BUG_ON(offset_in_entry(test, offset));
 828                 }
 829                 node = prev;
 830         }
 831         while (node) {
 832                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 833                 if (test->file_offset + test->len <= disk_i_size)
 834                         break;
 835                 if (test->file_offset >= i_size)
 836                         break;
 837                 if (test->file_offset >= disk_i_size)
 838                         goto out;
 839                 node = rb_prev(node);
 840         }
 841         new_i_size = min_t(u64, offset, i_size);
 842
 843         /*
 844          * at this point, we know we can safely update i_size to at least
 845          * the offset from this ordered extent.  But, we need to
 846          * walk forward and see if ios from higher up in the file have
 847          * finished.
 848          */
 849         if (ordered) {
 850                 node = rb_next(&ordered->rb_node);
 851         } else {
 852                 if (prev)
 853                         node = rb_next(prev);
 854                 else
 855                         node = rb_first(&tree->tree);
 856         }
 857         i_size_test = 0;
 858         if (node) {
 859                 /*
 860                  * do we have an area where IO might have finished
 861                  * between our ordered extent and the next one.
 862                  */
 863                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 864                 if (test->file_offset > offset)
 865                         i_size_test = test->file_offset;
 866         } else {
 867                 i_size_test = i_size;
 868         }
 869
 870         /*
 871          * i_size_test is the end of a region after this ordered
 872          * extent where there are no ordered extents.  As long as there
 873          * are no delalloc bytes in this area, it is safe to update
 874          * disk_i_size to the end of the region.
 875          */
 876         if (i_size_test > offset &&
 877             !test_range_bit(io_tree, offset, i_size_test - 1,
 878                             EXTENT_DELALLOC, 0, NULL)) {
 879                 new_i_size = min_t(u64, i_size_test, i_size);
 880         }
 881         BTRFS_I(inode)->disk_i_size = new_i_size;
 882         ret = 0;
 883 out:
 884         /*
 885          * we need to remove the ordered extent with the tree lock held
 886          * so that other people calling this function don't find our fully
 887          * processed ordered entry and skip updating the i_size
 888          */
 889         if (ordered)
 890                 __btrfs_remove_ordered_extent(inode, ordered);
 891         spin_unlock(&tree->lock);
 892         if (ordered)
 893                 wake_up(&ordered->wait);
 894         return ret;
 895 }
 896
 897 /*
 898  * search the ordered extents for one corresponding to 'offset' and
 899  * try to find a checksum.  This is used because we allow pages to
 900  * be reclaimed before their checksum is actually put into the btree
 901  */
 902 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
 903                            u32 *sum)
 904 {
 905         struct btrfs_ordered_sum *ordered_sum;
 906         struct btrfs_sector_sum *sector_sums;
 907         struct btrfs_ordered_extent *ordered;
 908         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 909         unsigned long num_sectors;
 910         unsigned long i;
 911         u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
 912         int ret = 1;
 913
 914         ordered = btrfs_lookup_ordered_extent(inode, offset);
 915         if (!ordered)
 916                 return 1;
 917
 918         spin_lock(&tree->lock);
 919         list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
 920                 if (disk_bytenr >= ordered_sum->bytenr) {
 921                         num_sectors = ordered_sum->len / sectorsize;
 922                         sector_sums = ordered_sum->sums;
 923                         for (i = 0; i < num_sectors; i++) {
 924                                 if (sector_sums[i].bytenr == disk_bytenr) {
 925                                         *sum = sector_sums[i].sum;
 926                                         ret = 0;
 927                                         goto out;
 928                                 }
 929                         }
 930                 }
 931         }
 932 out:
 933         spin_unlock(&tree->lock);
 934         btrfs_put_ordered_extent(ordered);
 935         return ret;
 936 }
 937
 938
 939 /*
 940  * add a given inode to the list of inodes that must be fully on
 941  * disk before a transaction commit finishes.
 942  *
 943  * This basically gives us the ext3 style data=ordered mode, and it is mostly
 944  * used to make sure renamed files are fully on disk.
 945  *
 946  * It is a noop if the inode is already fully on disk.
 947  *
 948  * If trans is not null, we'll do a friendly check for a transaction that
 949  * is already flushing things and force the IO down ourselves.
 950  */
 951 int btrfs_add_ordered_operation(struct btrfs_trans_handle *trans,
 952                                 struct btrfs_root *root,
 953                                 struct inode *inode)
 954 {
 955         u64 last_mod;
 956
 957         last_mod = max(BTRFS_I(inode)->generation, BTRFS_I(inode)->last_trans);
 958
 959         /*
 960          * if this file hasn't been changed since the last transaction
 961          * commit, we can safely return without doing anything
 962          */
 963         if (last_mod < root->fs_info->last_trans_committed)
 964                 return 0;
 965
 966         /*
 967          * the transaction is already committing.  Just start the IO and
 968          * don't bother with all of this list nonsense
 969          */
 970         if (trans && root->fs_info->running_transaction->blocked) {
 971                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
 972                 return 0;
 973         }
 974
 975         spin_lock(&root->fs_info->ordered_extent_lock);
 976         if (list_empty(&BTRFS_I(inode)->ordered_operations)) {
 977                 list_add_tail(&BTRFS_I(inode)->ordered_operations,
 978                               &root->fs_info->ordered_operations);
 979         }
 980         spin_unlock(&root->fs_info->ordered_extent_lock);
 981
 982         return 0;
 983 }