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 static void ordered_data_tree_panic(struct inode *inode, int errno,
  63                                                u64 offset)
  64 {
  65         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
  66         btrfs_panic(fs_info, errno, "Inconsistency in ordered tree at offset "
  67                     "%llu\n", (unsigned long long)offset);
  68 }
  69
  70 /*
  71  * look for a given offset in the tree, and if it can't be found return the
  72  * first lesser offset
  73  */
  74 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  75                                      struct rb_node **prev_ret)
  76 {
  77         struct rb_node *n = root->rb_node;
  78         struct rb_node *prev = NULL;
  79         struct rb_node *test;
  80         struct btrfs_ordered_extent *entry;
  81         struct btrfs_ordered_extent *prev_entry = NULL;
  82
  83         while (n) {
  84                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  85                 prev = n;
  86                 prev_entry = entry;
  87
  88                 if (file_offset < entry->file_offset)
  89                         n = n->rb_left;
  90                 else if (file_offset >= entry_end(entry))
  91                         n = n->rb_right;
  92                 else
  93                         return n;
  94         }
  95         if (!prev_ret)
  96                 return NULL;
  97
  98         while (prev && file_offset >= entry_end(prev_entry)) {
  99                 test = rb_next(prev);
 100                 if (!test)
 101                         break;
 102                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 103                                       rb_node);
 104                 if (file_offset < entry_end(prev_entry))
 105                         break;
 106
 107                 prev = test;
 108         }
 109         if (prev)
 110                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
 111                                       rb_node);
 112         while (prev && file_offset < entry_end(prev_entry)) {
 113                 test = rb_prev(prev);
 114                 if (!test)
 115                         break;
 116                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 117                                       rb_node);
 118                 prev = test;
 119         }
 120         *prev_ret = prev;
 121         return NULL;
 122 }
 123
 124 /*
 125  * helper to check if a given offset is inside a given entry
 126  */
 127 static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
 128 {
 129         if (file_offset < entry->file_offset ||
 130             entry->file_offset + entry->len <= file_offset)
 131                 return 0;
 132         return 1;
 133 }
 134
 135 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 136                           u64 len)
 137 {
 138         if (file_offset + len <= entry->file_offset ||
 139             entry->file_offset + entry->len <= file_offset)
 140                 return 0;
 141         return 1;
 142 }
 143
 144 /*
 145  * look find the first ordered struct that has this offset, otherwise
 146  * the first one less than this offset
 147  */
 148 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 149                                           u64 file_offset)
 150 {
 151         struct rb_root *root = &tree->tree;
 152         struct rb_node *prev = NULL;
 153         struct rb_node *ret;
 154         struct btrfs_ordered_extent *entry;
 155
 156         if (tree->last) {
 157                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 158                                  rb_node);
 159                 if (offset_in_entry(entry, file_offset))
 160                         return tree->last;
 161         }
 162         ret = __tree_search(root, file_offset, &prev);
 163         if (!ret)
 164                 ret = prev;
 165         if (ret)
 166                 tree->last = ret;
 167         return ret;
 168 }
 169
 170 /* allocate and add a new ordered_extent into the per-inode tree.
 171  * file_offset is the logical offset in the file
 172  *
 173  * start is the disk block number of an extent already reserved in the
 174  * extent allocation tree
 175  *
 176  * len is the length of the extent
 177  *
 178  * The tree is given a single reference on the ordered extent that was
 179  * inserted.
 180  */
 181 static int __btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 182                                       u64 start, u64 len, u64 disk_len,
 183                                       int type, int dio, int compress_type)
 184 {
 185         struct btrfs_ordered_inode_tree *tree;
 186         struct rb_node *node;
 187         struct btrfs_ordered_extent *entry;
 188
 189         tree = &BTRFS_I(inode)->ordered_tree;
 190         entry = kzalloc(sizeof(*entry), GFP_NOFS);
 191         if (!entry)
 192                 return -ENOMEM;
 193
 194         entry->file_offset = file_offset;
 195         entry->start = start;
 196         entry->len = len;
 197         entry->disk_len = disk_len;
 198         entry->bytes_left = len;
 199         entry->inode = igrab(inode);
 200         entry->compress_type = compress_type;
 201         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 202                 set_bit(type, &entry->flags);
 203
 204         if (dio)
 205                 set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
 206
 207         /* one ref for the tree */
 208         atomic_set(&entry->refs, 1);
 209         init_waitqueue_head(&entry->wait);
 210         INIT_LIST_HEAD(&entry->list);
 211         INIT_LIST_HEAD(&entry->root_extent_list);
 212
 213         trace_btrfs_ordered_extent_add(inode, entry);
 214
 215         spin_lock_irq(&tree->lock);
 216         node = tree_insert(&tree->tree, file_offset,
 217                            &entry->rb_node);
 218         if (node)
 219                 ordered_data_tree_panic(inode, -EEXIST, file_offset);
 220         spin_unlock_irq(&tree->lock);
 221
 222         spin_lock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
 223         list_add_tail(&entry->root_extent_list,
 224                       &BTRFS_I(inode)->root->fs_info->ordered_extents);
 225         spin_unlock(&BTRFS_I(inode)->root->fs_info->ordered_extent_lock);
 226
 227         return 0;
 228 }
 229
 230 int btrfs_add_ordered_extent(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, 0,
 235                                           BTRFS_COMPRESS_NONE);
 236 }
 237
 238 int btrfs_add_ordered_extent_dio(struct inode *inode, u64 file_offset,
 239                                  u64 start, u64 len, u64 disk_len, int type)
 240 {
 241         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 242                                           disk_len, type, 1,
 243                                           BTRFS_COMPRESS_NONE);
 244 }
 245
 246 int btrfs_add_ordered_extent_compress(struct inode *inode, u64 file_offset,
 247                                       u64 start, u64 len, u64 disk_len,
 248                                       int type, int compress_type)
 249 {
 250         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 251                                           disk_len, type, 0,
 252                                           compress_type);
 253 }
 254
 255 /*
 256  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 257  * when an ordered extent is finished.  If the list covers more than one
 258  * ordered extent, it is split across multiples.
 259  */
 260 void btrfs_add_ordered_sum(struct inode *inode,
 261                            struct btrfs_ordered_extent *entry,
 262                            struct btrfs_ordered_sum *sum)
 263 {
 264         struct btrfs_ordered_inode_tree *tree;
 265
 266         tree = &BTRFS_I(inode)->ordered_tree;
 267         spin_lock_irq(&tree->lock);
 268         list_add_tail(&sum->list, &entry->list);
 269         spin_unlock_irq(&tree->lock);
 270 }
 271
 272 /*
 273  * this is used to account for finished IO across a given range
 274  * of the file.  The IO may span ordered extents.  If
 275  * a given ordered_extent is completely done, 1 is returned, otherwise
 276  * 0.
 277  *
 278  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 279  * to make sure this function only returns 1 once for a given ordered extent.
 280  *
 281  * file_offset is updated to one byte past the range that is recorded as
 282  * complete.  This allows you to walk forward in the file.
 283  */
 284 int btrfs_dec_test_first_ordered_pending(struct inode *inode,
 285                                    struct btrfs_ordered_extent **cached,
 286                                    u64 *file_offset, u64 io_size, int uptodate)
 287 {
 288         struct btrfs_ordered_inode_tree *tree;
 289         struct rb_node *node;
 290         struct btrfs_ordered_extent *entry = NULL;
 291         int ret;
 292         unsigned long flags;
 293         u64 dec_end;
 294         u64 dec_start;
 295         u64 to_dec;
 296
 297         tree = &BTRFS_I(inode)->ordered_tree;
 298         spin_lock_irqsave(&tree->lock, flags);
 299         node = tree_search(tree, *file_offset);
 300         if (!node) {
 301                 ret = 1;
 302                 goto out;
 303         }
 304
 305         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 306         if (!offset_in_entry(entry, *file_offset)) {
 307                 ret = 1;
 308                 goto out;
 309         }
 310
 311         dec_start = max(*file_offset, entry->file_offset);
 312         dec_end = min(*file_offset + io_size, entry->file_offset +
 313                       entry->len);
 314         *file_offset = dec_end;
 315         if (dec_start > dec_end) {
 316                 printk(KERN_CRIT "bad ordering dec_start %llu end %llu\n",
 317                        (unsigned long long)dec_start,
 318                        (unsigned long long)dec_end);
 319         }
 320         to_dec = dec_end - dec_start;
 321         if (to_dec > entry->bytes_left) {
 322                 printk(KERN_CRIT "bad ordered accounting left %llu size %llu\n",
 323                        (unsigned long long)entry->bytes_left,
 324                        (unsigned long long)to_dec);
 325         }
 326         entry->bytes_left -= to_dec;
 327         if (!uptodate)
 328                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 329
 330         if (entry->bytes_left == 0)
 331                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 332         else
 333                 ret = 1;
 334 out:
 335         if (!ret && cached && entry) {
 336                 *cached = entry;
 337                 atomic_inc(&entry->refs);
 338         }
 339         spin_unlock_irqrestore(&tree->lock, flags);
 340         return ret == 0;
 341 }
 342
 343 /*
 344  * this is used to account for finished IO across a given range
 345  * of the file.  The IO should not span ordered extents.  If
 346  * a given ordered_extent is completely done, 1 is returned, otherwise
 347  * 0.
 348  *
 349  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 350  * to make sure this function only returns 1 once for a given ordered extent.
 351  */
 352 int btrfs_dec_test_ordered_pending(struct inode *inode,
 353                                    struct btrfs_ordered_extent **cached,
 354                                    u64 file_offset, u64 io_size, int uptodate)
 355 {
 356         struct btrfs_ordered_inode_tree *tree;
 357         struct rb_node *node;
 358         struct btrfs_ordered_extent *entry = NULL;
 359         unsigned long flags;
 360         int ret;
 361
 362         tree = &BTRFS_I(inode)->ordered_tree;
 363         spin_lock_irqsave(&tree->lock, flags);
 364         if (cached && *cached) {
 365                 entry = *cached;
 366                 goto have_entry;
 367         }
 368
 369         node = tree_search(tree, file_offset);
 370         if (!node) {
 371                 ret = 1;
 372                 goto out;
 373         }
 374
 375         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 376 have_entry:
 377         if (!offset_in_entry(entry, file_offset)) {
 378                 ret = 1;
 379                 goto out;
 380         }
 381
 382         if (io_size > entry->bytes_left) {
 383                 printk(KERN_CRIT "bad ordered accounting left %llu size %llu\n",
 384                        (unsigned long long)entry->bytes_left,
 385                        (unsigned long long)io_size);
 386         }
 387         entry->bytes_left -= io_size;
 388         if (!uptodate)
 389                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 390
 391         if (entry->bytes_left == 0)
 392                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 393         else
 394                 ret = 1;
 395 out:
 396         if (!ret && cached && entry) {
 397                 *cached = entry;
 398                 atomic_inc(&entry->refs);
 399         }
 400         spin_unlock_irqrestore(&tree->lock, flags);
 401         return ret == 0;
 402 }
 403
 404 /*
 405  * used to drop a reference on an ordered extent.  This will free
 406  * the extent if the last reference is dropped
 407  */
 408 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 409 {
 410         struct list_head *cur;
 411         struct btrfs_ordered_sum *sum;
 412
 413         trace_btrfs_ordered_extent_put(entry->inode, entry);
 414
 415         if (atomic_dec_and_test(&entry->refs)) {
 416                 if (entry->inode)
 417                         btrfs_add_delayed_iput(entry->inode);
 418                 while (!list_empty(&entry->list)) {
 419                         cur = entry->list.next;
 420                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 421                         list_del(&sum->list);
 422                         kfree(sum);
 423                 }
 424                 kfree(entry);
 425         }
 426 }
 427
 428 /*
 429  * remove an ordered extent from the tree.  No references are dropped
 430  * and waiters are woken up.
 431  */
 432 void btrfs_remove_ordered_extent(struct inode *inode,
 433                                  struct btrfs_ordered_extent *entry)
 434 {
 435         struct btrfs_ordered_inode_tree *tree;
 436         struct btrfs_root *root = BTRFS_I(inode)->root;
 437         struct rb_node *node;
 438
 439         tree = &BTRFS_I(inode)->ordered_tree;
 440         spin_lock_irq(&tree->lock);
 441         node = &entry->rb_node;
 442         rb_erase(node, &tree->tree);
 443         tree->last = NULL;
 444         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 445         spin_unlock_irq(&tree->lock);
 446
 447         spin_lock(&root->fs_info->ordered_extent_lock);
 448         list_del_init(&entry->root_extent_list);
 449
 450         trace_btrfs_ordered_extent_remove(inode, entry);
 451
 452         /*
 453          * we have no more ordered extents for this inode and
 454          * no dirty pages.  We can safely remove it from the
 455          * list of ordered extents
 456          */
 457         if (RB_EMPTY_ROOT(&tree->tree) &&
 458             !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) {
 459                 list_del_init(&BTRFS_I(inode)->ordered_operations);
 460         }
 461         spin_unlock(&root->fs_info->ordered_extent_lock);
 462         wake_up(&entry->wait);
 463 }
 464
 465 /*
 466  * wait for all the ordered extents in a root.  This is done when balancing
 467  * space between drives.
 468  */
 469 void btrfs_wait_ordered_extents(struct btrfs_root *root,
 470                                 int nocow_only, int delay_iput)
 471 {
 472         struct list_head splice;
 473         struct list_head *cur;
 474         struct btrfs_ordered_extent *ordered;
 475         struct inode *inode;
 476
 477         INIT_LIST_HEAD(&splice);
 478
 479         spin_lock(&root->fs_info->ordered_extent_lock);
 480         list_splice_init(&root->fs_info->ordered_extents, &splice);
 481         while (!list_empty(&splice)) {
 482                 cur = splice.next;
 483                 ordered = list_entry(cur, struct btrfs_ordered_extent,
 484                                      root_extent_list);
 485                 if (nocow_only &&
 486                     !test_bit(BTRFS_ORDERED_NOCOW, &ordered->flags) &&
 487                     !test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags)) {
 488                         list_move(&ordered->root_extent_list,
 489                                   &root->fs_info->ordered_extents);
 490                         cond_resched_lock(&root->fs_info->ordered_extent_lock);
 491                         continue;
 492                 }
 493
 494                 list_del_init(&ordered->root_extent_list);
 495                 atomic_inc(&ordered->refs);
 496
 497                 /*
 498                  * the inode may be getting freed (in sys_unlink path).
 499                  */
 500                 inode = igrab(ordered->inode);
 501
 502                 spin_unlock(&root->fs_info->ordered_extent_lock);
 503
 504                 if (inode) {
 505                         btrfs_start_ordered_extent(inode, ordered, 1);
 506                         btrfs_put_ordered_extent(ordered);
 507                         if (delay_iput)
 508                                 btrfs_add_delayed_iput(inode);
 509                         else
 510                                 iput(inode);
 511                 } else {
 512                         btrfs_put_ordered_extent(ordered);
 513                 }
 514
 515                 spin_lock(&root->fs_info->ordered_extent_lock);
 516         }
 517         spin_unlock(&root->fs_info->ordered_extent_lock);
 518 }
 519
 520 /*
 521  * this is used during transaction commit to write all the inodes
 522  * added to the ordered operation list.  These files must be fully on
 523  * disk before the transaction commits.
 524  *
 525  * we have two modes here, one is to just start the IO via filemap_flush
 526  * and the other is to wait for all the io.  When we wait, we have an
 527  * extra check to make sure the ordered operation list really is empty
 528  * before we return
 529  */
 530 void btrfs_run_ordered_operations(struct btrfs_root *root, int wait)
 531 {
 532         struct btrfs_inode *btrfs_inode;
 533         struct inode *inode;
 534         struct list_head splice;
 535
 536         INIT_LIST_HEAD(&splice);
 537
 538         mutex_lock(&root->fs_info->ordered_operations_mutex);
 539         spin_lock(&root->fs_info->ordered_extent_lock);
 540 again:
 541         list_splice_init(&root->fs_info->ordered_operations, &splice);
 542
 543         while (!list_empty(&splice)) {
 544                 btrfs_inode = list_entry(splice.next, struct btrfs_inode,
 545                                    ordered_operations);
 546
 547                 inode = &btrfs_inode->vfs_inode;
 548
 549                 list_del_init(&btrfs_inode->ordered_operations);
 550
 551                 /*
 552                  * the inode may be getting freed (in sys_unlink path).
 553                  */
 554                 inode = igrab(inode);
 555
 556                 if (!wait && inode) {
 557                         list_add_tail(&BTRFS_I(inode)->ordered_operations,
 558                               &root->fs_info->ordered_operations);
 559                 }
 560                 spin_unlock(&root->fs_info->ordered_extent_lock);
 561
 562                 if (inode) {
 563                         if (wait)
 564                                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
 565                         else
 566                                 filemap_flush(inode->i_mapping);
 567                         btrfs_add_delayed_iput(inode);
 568                 }
 569
 570                 cond_resched();
 571                 spin_lock(&root->fs_info->ordered_extent_lock);
 572         }
 573         if (wait && !list_empty(&root->fs_info->ordered_operations))
 574                 goto again;
 575
 576         spin_unlock(&root->fs_info->ordered_extent_lock);
 577         mutex_unlock(&root->fs_info->ordered_operations_mutex);
 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 void 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
 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         /*
 633          * So with compression we will find and lock a dirty page and clear the
 634          * first one as dirty, setup an async extent, and immediately return
 635          * with the entire range locked but with nobody actually marked with
 636          * writeback.  So we can't just filemap_write_and_wait_range() and
 637          * expect it to work since it will just kick off a thread to do the
 638          * actual work.  So we need to call filemap_fdatawrite_range _again_
 639          * since it will wait on the page lock, which won't be unlocked until
 640          * after the pages have been marked as writeback and so we're good to go
 641          * from there.  We have to do this otherwise we'll miss the ordered
 642          * extents and that results in badness.  Please Josef, do not think you
 643          * know better and pull this out at some point in the future, it is
 644          * right and you are wrong.
 645          */
 646         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
 647                      &BTRFS_I(inode)->runtime_flags))
 648                 filemap_fdatawrite_range(inode->i_mapping, start, orig_end);
 649
 650         filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 651
 652         end = orig_end;
 653         found = 0;
 654         while (1) {
 655                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
 656                 if (!ordered)
 657                         break;
 658                 if (ordered->file_offset > orig_end) {
 659                         btrfs_put_ordered_extent(ordered);
 660                         break;
 661                 }
 662                 if (ordered->file_offset + ordered->len < start) {
 663                         btrfs_put_ordered_extent(ordered);
 664                         break;
 665                 }
 666                 found++;
 667                 btrfs_start_ordered_extent(inode, ordered, 1);
 668                 end = ordered->file_offset;
 669                 btrfs_put_ordered_extent(ordered);
 670                 if (end == 0 || end == start)
 671                         break;
 672                 end--;
 673         }
 674 }
 675
 676 /*
 677  * find an ordered extent corresponding to file_offset.  return NULL if
 678  * nothing is found, otherwise take a reference on the extent and return it
 679  */
 680 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
 681                                                          u64 file_offset)
 682 {
 683         struct btrfs_ordered_inode_tree *tree;
 684         struct rb_node *node;
 685         struct btrfs_ordered_extent *entry = NULL;
 686
 687         tree = &BTRFS_I(inode)->ordered_tree;
 688         spin_lock_irq(&tree->lock);
 689         node = tree_search(tree, file_offset);
 690         if (!node)
 691                 goto out;
 692
 693         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 694         if (!offset_in_entry(entry, file_offset))
 695                 entry = NULL;
 696         if (entry)
 697                 atomic_inc(&entry->refs);
 698 out:
 699         spin_unlock_irq(&tree->lock);
 700         return entry;
 701 }
 702
 703 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 704  * extents that exist in the range, rather than just the start of the range.
 705  */
 706 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(struct inode *inode,
 707                                                         u64 file_offset,
 708                                                         u64 len)
 709 {
 710         struct btrfs_ordered_inode_tree *tree;
 711         struct rb_node *node;
 712         struct btrfs_ordered_extent *entry = NULL;
 713
 714         tree = &BTRFS_I(inode)->ordered_tree;
 715         spin_lock_irq(&tree->lock);
 716         node = tree_search(tree, file_offset);
 717         if (!node) {
 718                 node = tree_search(tree, file_offset + len);
 719                 if (!node)
 720                         goto out;
 721         }
 722
 723         while (1) {
 724                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 725                 if (range_overlaps(entry, file_offset, len))
 726                         break;
 727
 728                 if (entry->file_offset >= file_offset + len) {
 729                         entry = NULL;
 730                         break;
 731                 }
 732                 entry = NULL;
 733                 node = rb_next(node);
 734                 if (!node)
 735                         break;
 736         }
 737 out:
 738         if (entry)
 739                 atomic_inc(&entry->refs);
 740         spin_unlock_irq(&tree->lock);
 741         return entry;
 742 }
 743
 744 /*
 745  * lookup and return any extent before 'file_offset'.  NULL is returned
 746  * if none is found
 747  */
 748 struct btrfs_ordered_extent *
 749 btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
 750 {
 751         struct btrfs_ordered_inode_tree *tree;
 752         struct rb_node *node;
 753         struct btrfs_ordered_extent *entry = NULL;
 754
 755         tree = &BTRFS_I(inode)->ordered_tree;
 756         spin_lock_irq(&tree->lock);
 757         node = tree_search(tree, file_offset);
 758         if (!node)
 759                 goto out;
 760
 761         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 762         atomic_inc(&entry->refs);
 763 out:
 764         spin_unlock_irq(&tree->lock);
 765         return entry;
 766 }
 767
 768 /*
 769  * After an extent is done, call this to conditionally update the on disk
 770  * i_size.  i_size is updated to cover any fully written part of the file.
 771  */
 772 int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
 773                                 struct btrfs_ordered_extent *ordered)
 774 {
 775         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 776         u64 disk_i_size;
 777         u64 new_i_size;
 778         u64 i_size_test;
 779         u64 i_size = i_size_read(inode);
 780         struct rb_node *node;
 781         struct rb_node *prev = NULL;
 782         struct btrfs_ordered_extent *test;
 783         int ret = 1;
 784
 785         if (ordered)
 786                 offset = entry_end(ordered);
 787         else
 788                 offset = ALIGN(offset, BTRFS_I(inode)->root->sectorsize);
 789
 790         spin_lock_irq(&tree->lock);
 791         disk_i_size = BTRFS_I(inode)->disk_i_size;
 792
 793         /* truncate file */
 794         if (disk_i_size > i_size) {
 795                 BTRFS_I(inode)->disk_i_size = i_size;
 796                 ret = 0;
 797                 goto out;
 798         }
 799
 800         /*
 801          * if the disk i_size is already at the inode->i_size, or
 802          * this ordered extent is inside the disk i_size, we're done
 803          */
 804         if (disk_i_size == i_size || offset <= disk_i_size) {
 805                 goto out;
 806         }
 807
 808         /*
 809          * walk backward from this ordered extent to disk_i_size.
 810          * if we find an ordered extent then we can't update disk i_size
 811          * yet
 812          */
 813         if (ordered) {
 814                 node = rb_prev(&ordered->rb_node);
 815         } else {
 816                 prev = tree_search(tree, offset);
 817                 /*
 818                  * we insert file extents without involving ordered struct,
 819                  * so there should be no ordered struct cover this offset
 820                  */
 821                 if (prev) {
 822                         test = rb_entry(prev, struct btrfs_ordered_extent,
 823                                         rb_node);
 824                         BUG_ON(offset_in_entry(test, offset));
 825                 }
 826                 node = prev;
 827         }
 828         for (; node; node = rb_prev(node)) {
 829                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 830
 831                 /* We treat this entry as if it doesnt exist */
 832                 if (test_bit(BTRFS_ORDERED_UPDATED_ISIZE, &test->flags))
 833                         continue;
 834                 if (test->file_offset + test->len <= disk_i_size)
 835                         break;
 836                 if (test->file_offset >= i_size)
 837                         break;
 838                 if (test->file_offset >= disk_i_size)
 839                         goto out;
 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
 858         /*
 859          * We are looking for an area between our current extent and the next
 860          * ordered extent to update the i_size to.  There are 3 cases here
 861          *
 862          * 1) We don't actually have anything and we can update to i_size.
 863          * 2) We have stuff but they already did their i_size update so again we
 864          * can just update to i_size.
 865          * 3) We have an outstanding ordered extent so the most we can update
 866          * our disk_i_size to is the start of the next offset.
 867          */
 868         i_size_test = i_size;
 869         for (; node; node = rb_next(node)) {
 870                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 871
 872                 if (test_bit(BTRFS_ORDERED_UPDATED_ISIZE, &test->flags))
 873                         continue;
 874                 if (test->file_offset > offset) {
 875                         i_size_test = test->file_offset;
 876                         break;
 877                 }
 878         }
 879
 880         /*
 881          * i_size_test is the end of a region after this ordered
 882          * extent where there are no ordered extents, we can safely set
 883          * disk_i_size to this.
 884          */
 885         if (i_size_test > offset)
 886                 new_i_size = min_t(u64, i_size_test, i_size);
 887         BTRFS_I(inode)->disk_i_size = new_i_size;
 888         ret = 0;
 889 out:
 890         /*
 891          * We need to do this because we can't remove ordered extents until
 892          * after the i_disk_size has been updated and then the inode has been
 893          * updated to reflect the change, so we need to tell anybody who finds
 894          * this ordered extent that we've already done all the real work, we
 895          * just haven't completed all the other work.
 896          */
 897         if (ordered)
 898                 set_bit(BTRFS_ORDERED_UPDATED_ISIZE, &ordered->flags);
 899         spin_unlock_irq(&tree->lock);
 900         return ret;
 901 }
 902
 903 /*
 904  * search the ordered extents for one corresponding to 'offset' and
 905  * try to find a checksum.  This is used because we allow pages to
 906  * be reclaimed before their checksum is actually put into the btree
 907  */
 908 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
 909                            u32 *sum)
 910 {
 911         struct btrfs_ordered_sum *ordered_sum;
 912         struct btrfs_sector_sum *sector_sums;
 913         struct btrfs_ordered_extent *ordered;
 914         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 915         unsigned long num_sectors;
 916         unsigned long i;
 917         u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
 918         int ret = 1;
 919
 920         ordered = btrfs_lookup_ordered_extent(inode, offset);
 921         if (!ordered)
 922                 return 1;
 923
 924         spin_lock_irq(&tree->lock);
 925         list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
 926                 if (disk_bytenr >= ordered_sum->bytenr) {
 927                         num_sectors = ordered_sum->len / sectorsize;
 928                         sector_sums = ordered_sum->sums;
 929                         for (i = 0; i < num_sectors; i++) {
 930                                 if (sector_sums[i].bytenr == disk_bytenr) {
 931                                         *sum = sector_sums[i].sum;
 932                                         ret = 0;
 933                                         goto out;
 934                                 }
 935                         }
 936                 }
 937         }
 938 out:
 939         spin_unlock_irq(&tree->lock);
 940         btrfs_put_ordered_extent(ordered);
 941         return ret;
 942 }
 943
 944
 945 /*
 946  * add a given inode to the list of inodes that must be fully on
 947  * disk before a transaction commit finishes.
 948  *
 949  * This basically gives us the ext3 style data=ordered mode, and it is mostly
 950  * used to make sure renamed files are fully on disk.
 951  *
 952  * It is a noop if the inode is already fully on disk.
 953  *
 954  * If trans is not null, we'll do a friendly check for a transaction that
 955  * is already flushing things and force the IO down ourselves.
 956  */
 957 void btrfs_add_ordered_operation(struct btrfs_trans_handle *trans,
 958                                  struct btrfs_root *root, struct inode *inode)
 959 {
 960         u64 last_mod;
 961
 962         last_mod = max(BTRFS_I(inode)->generation, BTRFS_I(inode)->last_trans);
 963
 964         /*
 965          * if this file hasn't been changed since the last transaction
 966          * commit, we can safely return without doing anything
 967          */
 968         if (last_mod < root->fs_info->last_trans_committed)
 969                 return;
 970
 971         /*
 972          * the transaction is already committing.  Just start the IO and
 973          * don't bother with all of this list nonsense
 974          */
 975         if (trans && root->fs_info->running_transaction->blocked) {
 976                 btrfs_wait_ordered_range(inode, 0, (u64)-1);
 977                 return;
 978         }
 979
 980         spin_lock(&root->fs_info->ordered_extent_lock);
 981         if (list_empty(&BTRFS_I(inode)->ordered_operations)) {
 982                 list_add_tail(&BTRFS_I(inode)->ordered_operations,
 983                               &root->fs_info->ordered_operations);
 984         }
 985         spin_unlock(&root->fs_info->ordered_extent_lock);
 986 }