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 #include "disk-io.h"
  28
  29 static struct kmem_cache *btrfs_ordered_extent_cache;
  30
  31 static u64 entry_end(struct btrfs_ordered_extent *entry)
  32 {
  33         if (entry->file_offset + entry->len < entry->file_offset)
  34                 return (u64)-1;
  35         return entry->file_offset + entry->len;
  36 }
  37
  38 /* returns NULL if the insertion worked, or it returns the node it did find
  39  * in the tree
  40  */
  41 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  42                                    struct rb_node *node)
  43 {
  44         struct rb_node **p = &root->rb_node;
  45         struct rb_node *parent = NULL;
  46         struct btrfs_ordered_extent *entry;
  47
  48         while (*p) {
  49                 parent = *p;
  50                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  51
  52                 if (file_offset < entry->file_offset)
  53                         p = &(*p)->rb_left;
  54                 else if (file_offset >= entry_end(entry))
  55                         p = &(*p)->rb_right;
  56                 else
  57                         return parent;
  58         }
  59
  60         rb_link_node(node, parent, p);
  61         rb_insert_color(node, root);
  62         return NULL;
  63 }
  64
  65 static void ordered_data_tree_panic(struct inode *inode, int errno,
  66                                                u64 offset)
  67 {
  68         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
  69         btrfs_panic(fs_info, errno, "Inconsistency in ordered tree at offset "
  70                     "%llu", offset);
  71 }
  72
  73 /*
  74  * look for a given offset in the tree, and if it can't be found return the
  75  * first lesser offset
  76  */
  77 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  78                                      struct rb_node **prev_ret)
  79 {
  80         struct rb_node *n = root->rb_node;
  81         struct rb_node *prev = NULL;
  82         struct rb_node *test;
  83         struct btrfs_ordered_extent *entry;
  84         struct btrfs_ordered_extent *prev_entry = NULL;
  85
  86         while (n) {
  87                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  88                 prev = n;
  89                 prev_entry = entry;
  90
  91                 if (file_offset < entry->file_offset)
  92                         n = n->rb_left;
  93                 else if (file_offset >= entry_end(entry))
  94                         n = n->rb_right;
  95                 else
  96                         return n;
  97         }
  98         if (!prev_ret)
  99                 return NULL;
 100
 101         while (prev && file_offset >= entry_end(prev_entry)) {
 102                 test = rb_next(prev);
 103                 if (!test)
 104                         break;
 105                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 106                                       rb_node);
 107                 if (file_offset < entry_end(prev_entry))
 108                         break;
 109
 110                 prev = test;
 111         }
 112         if (prev)
 113                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
 114                                       rb_node);
 115         while (prev && file_offset < entry_end(prev_entry)) {
 116                 test = rb_prev(prev);
 117                 if (!test)
 118                         break;
 119                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 120                                       rb_node);
 121                 prev = test;
 122         }
 123         *prev_ret = prev;
 124         return NULL;
 125 }
 126
 127 /*
 128  * helper to check if a given offset is inside a given entry
 129  */
 130 static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
 131 {
 132         if (file_offset < entry->file_offset ||
 133             entry->file_offset + entry->len <= file_offset)
 134                 return 0;
 135         return 1;
 136 }
 137
 138 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 139                           u64 len)
 140 {
 141         if (file_offset + len <= entry->file_offset ||
 142             entry->file_offset + entry->len <= file_offset)
 143                 return 0;
 144         return 1;
 145 }
 146
 147 /*
 148  * look find the first ordered struct that has this offset, otherwise
 149  * the first one less than this offset
 150  */
 151 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 152                                           u64 file_offset)
 153 {
 154         struct rb_root *root = &tree->tree;
 155         struct rb_node *prev = NULL;
 156         struct rb_node *ret;
 157         struct btrfs_ordered_extent *entry;
 158
 159         if (tree->last) {
 160                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 161                                  rb_node);
 162                 if (offset_in_entry(entry, file_offset))
 163                         return tree->last;
 164         }
 165         ret = __tree_search(root, file_offset, &prev);
 166         if (!ret)
 167                 ret = prev;
 168         if (ret)
 169                 tree->last = ret;
 170         return ret;
 171 }
 172
 173 /* allocate and add a new ordered_extent into the per-inode tree.
 174  * file_offset is the logical offset in the file
 175  *
 176  * start is the disk block number of an extent already reserved in the
 177  * extent allocation tree
 178  *
 179  * len is the length of the extent
 180  *
 181  * The tree is given a single reference on the ordered extent that was
 182  * inserted.
 183  */
 184 static int __btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 185                                       u64 start, u64 len, u64 disk_len,
 186                                       int type, int dio, int compress_type)
 187 {
 188         struct btrfs_root *root = BTRFS_I(inode)->root;
 189         struct btrfs_ordered_inode_tree *tree;
 190         struct rb_node *node;
 191         struct btrfs_ordered_extent *entry;
 192
 193         tree = &BTRFS_I(inode)->ordered_tree;
 194         entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 195         if (!entry)
 196                 return -ENOMEM;
 197
 198         entry->file_offset = file_offset;
 199         entry->start = start;
 200         entry->len = len;
 201         entry->disk_len = disk_len;
 202         entry->bytes_left = len;
 203         entry->inode = igrab(inode);
 204         entry->compress_type = compress_type;
 205         entry->truncated_len = (u64)-1;
 206         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 207                 set_bit(type, &entry->flags);
 208
 209         if (dio)
 210                 set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
 211
 212         /* one ref for the tree */
 213         atomic_set(&entry->refs, 1);
 214         init_waitqueue_head(&entry->wait);
 215         INIT_LIST_HEAD(&entry->list);
 216         INIT_LIST_HEAD(&entry->root_extent_list);
 217         INIT_LIST_HEAD(&entry->work_list);
 218         init_completion(&entry->completion);
 219         INIT_LIST_HEAD(&entry->log_list);
 220         INIT_LIST_HEAD(&entry->trans_list);
 221
 222         trace_btrfs_ordered_extent_add(inode, entry);
 223
 224         spin_lock_irq(&tree->lock);
 225         node = tree_insert(&tree->tree, file_offset,
 226                            &entry->rb_node);
 227         if (node)
 228                 ordered_data_tree_panic(inode, -EEXIST, file_offset);
 229         spin_unlock_irq(&tree->lock);
 230
 231         spin_lock(&root->ordered_extent_lock);
 232         list_add_tail(&entry->root_extent_list,
 233                       &root->ordered_extents);
 234         root->nr_ordered_extents++;
 235         if (root->nr_ordered_extents == 1) {
 236                 spin_lock(&root->fs_info->ordered_root_lock);
 237                 BUG_ON(!list_empty(&root->ordered_root));
 238                 list_add_tail(&root->ordered_root,
 239                               &root->fs_info->ordered_roots);
 240                 spin_unlock(&root->fs_info->ordered_root_lock);
 241         }
 242         spin_unlock(&root->ordered_extent_lock);
 243
 244         return 0;
 245 }
 246
 247 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 248                              u64 start, u64 len, u64 disk_len, int type)
 249 {
 250         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 251                                           disk_len, type, 0,
 252                                           BTRFS_COMPRESS_NONE);
 253 }
 254
 255 int btrfs_add_ordered_extent_dio(struct inode *inode, u64 file_offset,
 256                                  u64 start, u64 len, u64 disk_len, int type)
 257 {
 258         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 259                                           disk_len, type, 1,
 260                                           BTRFS_COMPRESS_NONE);
 261 }
 262
 263 int btrfs_add_ordered_extent_compress(struct inode *inode, u64 file_offset,
 264                                       u64 start, u64 len, u64 disk_len,
 265                                       int type, int compress_type)
 266 {
 267         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 268                                           disk_len, type, 0,
 269                                           compress_type);
 270 }
 271
 272 /*
 273  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 274  * when an ordered extent is finished.  If the list covers more than one
 275  * ordered extent, it is split across multiples.
 276  */
 277 void btrfs_add_ordered_sum(struct inode *inode,
 278                            struct btrfs_ordered_extent *entry,
 279                            struct btrfs_ordered_sum *sum)
 280 {
 281         struct btrfs_ordered_inode_tree *tree;
 282
 283         tree = &BTRFS_I(inode)->ordered_tree;
 284         spin_lock_irq(&tree->lock);
 285         list_add_tail(&sum->list, &entry->list);
 286         spin_unlock_irq(&tree->lock);
 287 }
 288
 289 /*
 290  * this is used to account for finished IO across a given range
 291  * of the file.  The IO may span ordered extents.  If
 292  * a given ordered_extent is completely done, 1 is returned, otherwise
 293  * 0.
 294  *
 295  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 296  * to make sure this function only returns 1 once for a given ordered extent.
 297  *
 298  * file_offset is updated to one byte past the range that is recorded as
 299  * complete.  This allows you to walk forward in the file.
 300  */
 301 int btrfs_dec_test_first_ordered_pending(struct inode *inode,
 302                                    struct btrfs_ordered_extent **cached,
 303                                    u64 *file_offset, u64 io_size, int uptodate)
 304 {
 305         struct btrfs_ordered_inode_tree *tree;
 306         struct rb_node *node;
 307         struct btrfs_ordered_extent *entry = NULL;
 308         int ret;
 309         unsigned long flags;
 310         u64 dec_end;
 311         u64 dec_start;
 312         u64 to_dec;
 313
 314         tree = &BTRFS_I(inode)->ordered_tree;
 315         spin_lock_irqsave(&tree->lock, flags);
 316         node = tree_search(tree, *file_offset);
 317         if (!node) {
 318                 ret = 1;
 319                 goto out;
 320         }
 321
 322         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 323         if (!offset_in_entry(entry, *file_offset)) {
 324                 ret = 1;
 325                 goto out;
 326         }
 327
 328         dec_start = max(*file_offset, entry->file_offset);
 329         dec_end = min(*file_offset + io_size, entry->file_offset +
 330                       entry->len);
 331         *file_offset = dec_end;
 332         if (dec_start > dec_end) {
 333                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
 334                         "bad ordering dec_start %llu end %llu", dec_start, dec_end);
 335         }
 336         to_dec = dec_end - dec_start;
 337         if (to_dec > entry->bytes_left) {
 338                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
 339                         "bad ordered accounting left %llu size %llu",
 340                         entry->bytes_left, to_dec);
 341         }
 342         entry->bytes_left -= to_dec;
 343         if (!uptodate)
 344                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 345
 346         if (entry->bytes_left == 0) {
 347                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 348                 if (waitqueue_active(&entry->wait))
 349                         wake_up(&entry->wait);
 350         } else {
 351                 ret = 1;
 352         }
 353 out:
 354         if (!ret && cached && entry) {
 355                 *cached = entry;
 356                 atomic_inc(&entry->refs);
 357         }
 358         spin_unlock_irqrestore(&tree->lock, flags);
 359         return ret == 0;
 360 }
 361
 362 /*
 363  * this is used to account for finished IO across a given range
 364  * of the file.  The IO should not span ordered extents.  If
 365  * a given ordered_extent is completely done, 1 is returned, otherwise
 366  * 0.
 367  *
 368  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 369  * to make sure this function only returns 1 once for a given ordered extent.
 370  */
 371 int btrfs_dec_test_ordered_pending(struct inode *inode,
 372                                    struct btrfs_ordered_extent **cached,
 373                                    u64 file_offset, u64 io_size, int uptodate)
 374 {
 375         struct btrfs_ordered_inode_tree *tree;
 376         struct rb_node *node;
 377         struct btrfs_ordered_extent *entry = NULL;
 378         unsigned long flags;
 379         int ret;
 380
 381         tree = &BTRFS_I(inode)->ordered_tree;
 382         spin_lock_irqsave(&tree->lock, flags);
 383         if (cached && *cached) {
 384                 entry = *cached;
 385                 goto have_entry;
 386         }
 387
 388         node = tree_search(tree, file_offset);
 389         if (!node) {
 390                 ret = 1;
 391                 goto out;
 392         }
 393
 394         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 395 have_entry:
 396         if (!offset_in_entry(entry, file_offset)) {
 397                 ret = 1;
 398                 goto out;
 399         }
 400
 401         if (io_size > entry->bytes_left) {
 402                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
 403                            "bad ordered accounting left %llu size %llu",
 404                        entry->bytes_left, io_size);
 405         }
 406         entry->bytes_left -= io_size;
 407         if (!uptodate)
 408                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 409
 410         if (entry->bytes_left == 0) {
 411                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 412                 if (waitqueue_active(&entry->wait))
 413                         wake_up(&entry->wait);
 414         } else {
 415                 ret = 1;
 416         }
 417 out:
 418         if (!ret && cached && entry) {
 419                 *cached = entry;
 420                 atomic_inc(&entry->refs);
 421         }
 422         spin_unlock_irqrestore(&tree->lock, flags);
 423         return ret == 0;
 424 }
 425
 426 /* Needs to either be called under a log transaction or the log_mutex */
 427 void btrfs_get_logged_extents(struct inode *inode,
 428                               struct list_head *logged_list,
 429                               const loff_t start,
 430                               const loff_t end)
 431 {
 432         struct btrfs_ordered_inode_tree *tree;
 433         struct btrfs_ordered_extent *ordered;
 434         struct rb_node *n;
 435         struct rb_node *prev;
 436
 437         tree = &BTRFS_I(inode)->ordered_tree;
 438         spin_lock_irq(&tree->lock);
 439         n = __tree_search(&tree->tree, end, &prev);
 440         if (!n)
 441                 n = prev;
 442         for (; n; n = rb_prev(n)) {
 443                 ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
 444                 if (ordered->file_offset > end)
 445                         continue;
 446                 if (entry_end(ordered) <= start)
 447                         break;
 448                 if (test_and_set_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
 449                         continue;
 450                 list_add(&ordered->log_list, logged_list);
 451                 atomic_inc(&ordered->refs);
 452         }
 453         spin_unlock_irq(&tree->lock);
 454 }
 455
 456 void btrfs_put_logged_extents(struct list_head *logged_list)
 457 {
 458         struct btrfs_ordered_extent *ordered;
 459
 460         while (!list_empty(logged_list)) {
 461                 ordered = list_first_entry(logged_list,
 462                                            struct btrfs_ordered_extent,
 463                                            log_list);
 464                 list_del_init(&ordered->log_list);
 465                 btrfs_put_ordered_extent(ordered);
 466         }
 467 }
 468
 469 void btrfs_submit_logged_extents(struct list_head *logged_list,
 470                                  struct btrfs_root *log)
 471 {
 472         int index = log->log_transid % 2;
 473
 474         spin_lock_irq(&log->log_extents_lock[index]);
 475         list_splice_tail(logged_list, &log->logged_list[index]);
 476         spin_unlock_irq(&log->log_extents_lock[index]);
 477 }
 478
 479 void btrfs_wait_logged_extents(struct btrfs_trans_handle *trans,
 480                                struct btrfs_root *log, u64 transid)
 481 {
 482         struct btrfs_ordered_extent *ordered;
 483         int index = transid % 2;
 484
 485         spin_lock_irq(&log->log_extents_lock[index]);
 486         while (!list_empty(&log->logged_list[index])) {
 487                 ordered = list_first_entry(&log->logged_list[index],
 488                                            struct btrfs_ordered_extent,
 489                                            log_list);
 490                 list_del_init(&ordered->log_list);
 491                 spin_unlock_irq(&log->log_extents_lock[index]);
 492
 493                 if (!test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags) &&
 494                     !test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags)) {
 495                         struct inode *inode = ordered->inode;
 496                         u64 start = ordered->file_offset;
 497                         u64 end = ordered->file_offset + ordered->len - 1;
 498
 499                         WARN_ON(!inode);
 500                         filemap_fdatawrite_range(inode->i_mapping, start, end);
 501                 }
 502                 wait_event(ordered->wait, test_bit(BTRFS_ORDERED_IO_DONE,
 503                                                    &ordered->flags));
 504
 505                 /*
 506                  * If our ordered extent completed it means it updated the
 507                  * fs/subvol and csum trees already, so no need to make the
 508                  * current transaction's commit wait for it, as we end up
 509                  * holding memory unnecessarily and delaying the inode's iput
 510                  * until the transaction commit (we schedule an iput for the
 511                  * inode when the ordered extent's refcount drops to 0), which
 512                  * prevents it from being evictable until the transaction
 513                  * commits.
 514                  */
 515                 if (test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags))
 516                         btrfs_put_ordered_extent(ordered);
 517                 else
 518                         list_add_tail(&ordered->trans_list, &trans->ordered);
 519
 520                 spin_lock_irq(&log->log_extents_lock[index]);
 521         }
 522         spin_unlock_irq(&log->log_extents_lock[index]);
 523 }
 524
 525 void btrfs_free_logged_extents(struct btrfs_root *log, u64 transid)
 526 {
 527         struct btrfs_ordered_extent *ordered;
 528         int index = transid % 2;
 529
 530         spin_lock_irq(&log->log_extents_lock[index]);
 531         while (!list_empty(&log->logged_list[index])) {
 532                 ordered = list_first_entry(&log->logged_list[index],
 533                                            struct btrfs_ordered_extent,
 534                                            log_list);
 535                 list_del_init(&ordered->log_list);
 536                 spin_unlock_irq(&log->log_extents_lock[index]);
 537                 btrfs_put_ordered_extent(ordered);
 538                 spin_lock_irq(&log->log_extents_lock[index]);
 539         }
 540         spin_unlock_irq(&log->log_extents_lock[index]);
 541 }
 542
 543 /*
 544  * used to drop a reference on an ordered extent.  This will free
 545  * the extent if the last reference is dropped
 546  */
 547 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 548 {
 549         struct list_head *cur;
 550         struct btrfs_ordered_sum *sum;
 551
 552         trace_btrfs_ordered_extent_put(entry->inode, entry);
 553
 554         if (atomic_dec_and_test(&entry->refs)) {
 555                 if (entry->inode)
 556                         btrfs_add_delayed_iput(entry->inode);
 557                 while (!list_empty(&entry->list)) {
 558                         cur = entry->list.next;
 559                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 560                         list_del(&sum->list);
 561                         kfree(sum);
 562                 }
 563                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
 564         }
 565 }
 566
 567 /*
 568  * remove an ordered extent from the tree.  No references are dropped
 569  * and waiters are woken up.
 570  */
 571 void btrfs_remove_ordered_extent(struct inode *inode,
 572                                  struct btrfs_ordered_extent *entry)
 573 {
 574         struct btrfs_ordered_inode_tree *tree;
 575         struct btrfs_root *root = BTRFS_I(inode)->root;
 576         struct rb_node *node;
 577
 578         tree = &BTRFS_I(inode)->ordered_tree;
 579         spin_lock_irq(&tree->lock);
 580         node = &entry->rb_node;
 581         rb_erase(node, &tree->tree);
 582         if (tree->last == node)
 583                 tree->last = NULL;
 584         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 585         spin_unlock_irq(&tree->lock);
 586
 587         spin_lock(&root->ordered_extent_lock);
 588         list_del_init(&entry->root_extent_list);
 589         root->nr_ordered_extents--;
 590
 591         trace_btrfs_ordered_extent_remove(inode, entry);
 592
 593         if (!root->nr_ordered_extents) {
 594                 spin_lock(&root->fs_info->ordered_root_lock);
 595                 BUG_ON(list_empty(&root->ordered_root));
 596                 list_del_init(&root->ordered_root);
 597                 spin_unlock(&root->fs_info->ordered_root_lock);
 598         }
 599         spin_unlock(&root->ordered_extent_lock);
 600         wake_up(&entry->wait);
 601 }
 602
 603 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 604 {
 605         struct btrfs_ordered_extent *ordered;
 606
 607         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 608         btrfs_start_ordered_extent(ordered->inode, ordered, 1);
 609         complete(&ordered->completion);
 610 }
 611
 612 /*
 613  * wait for all the ordered extents in a root.  This is done when balancing
 614  * space between drives.
 615  */
 616 int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)
 617 {
 618         struct list_head splice, works;
 619         struct btrfs_ordered_extent *ordered, *next;
 620         int count = 0;
 621
 622         INIT_LIST_HEAD(&splice);
 623         INIT_LIST_HEAD(&works);
 624
 625         mutex_lock(&root->ordered_extent_mutex);
 626         spin_lock(&root->ordered_extent_lock);
 627         list_splice_init(&root->ordered_extents, &splice);
 628         while (!list_empty(&splice) && nr) {
 629                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 630                                            root_extent_list);
 631                 list_move_tail(&ordered->root_extent_list,
 632                                &root->ordered_extents);
 633                 atomic_inc(&ordered->refs);
 634                 spin_unlock(&root->ordered_extent_lock);
 635
 636                 btrfs_init_work(&ordered->flush_work,
 637                                 btrfs_flush_delalloc_helper,
 638                                 btrfs_run_ordered_extent_work, NULL, NULL);
 639                 list_add_tail(&ordered->work_list, &works);
 640                 btrfs_queue_work(root->fs_info->flush_workers,
 641                                  &ordered->flush_work);
 642
 643                 cond_resched();
 644                 spin_lock(&root->ordered_extent_lock);
 645                 if (nr != -1)
 646                         nr--;
 647                 count++;
 648         }
 649         list_splice_tail(&splice, &root->ordered_extents);
 650         spin_unlock(&root->ordered_extent_lock);
 651
 652         list_for_each_entry_safe(ordered, next, &works, work_list) {
 653                 list_del_init(&ordered->work_list);
 654                 wait_for_completion(&ordered->completion);
 655                 btrfs_put_ordered_extent(ordered);
 656                 cond_resched();
 657         }
 658         mutex_unlock(&root->ordered_extent_mutex);
 659
 660         return count;
 661 }
 662
 663 void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, int nr)
 664 {
 665         struct btrfs_root *root;
 666         struct list_head splice;
 667         int done;
 668
 669         INIT_LIST_HEAD(&splice);
 670
 671         mutex_lock(&fs_info->ordered_operations_mutex);
 672         spin_lock(&fs_info->ordered_root_lock);
 673         list_splice_init(&fs_info->ordered_roots, &splice);
 674         while (!list_empty(&splice) && nr) {
 675                 root = list_first_entry(&splice, struct btrfs_root,
 676                                         ordered_root);
 677                 root = btrfs_grab_fs_root(root);
 678                 BUG_ON(!root);
 679                 list_move_tail(&root->ordered_root,
 680                                &fs_info->ordered_roots);
 681                 spin_unlock(&fs_info->ordered_root_lock);
 682
 683                 done = btrfs_wait_ordered_extents(root, nr);
 684                 btrfs_put_fs_root(root);
 685
 686                 spin_lock(&fs_info->ordered_root_lock);
 687                 if (nr != -1) {
 688                         nr -= done;
 689                         WARN_ON(nr < 0);
 690                 }
 691         }
 692         list_splice_tail(&splice, &fs_info->ordered_roots);
 693         spin_unlock(&fs_info->ordered_root_lock);
 694         mutex_unlock(&fs_info->ordered_operations_mutex);
 695 }
 696
 697 /*
 698  * Used to start IO or wait for a given ordered extent to finish.
 699  *
 700  * If wait is one, this effectively waits on page writeback for all the pages
 701  * in the extent, and it waits on the io completion code to insert
 702  * metadata into the btree corresponding to the extent
 703  */
 704 void btrfs_start_ordered_extent(struct inode *inode,
 705                                        struct btrfs_ordered_extent *entry,
 706                                        int wait)
 707 {
 708         u64 start = entry->file_offset;
 709         u64 end = start + entry->len - 1;
 710
 711         trace_btrfs_ordered_extent_start(inode, entry);
 712
 713         /*
 714          * pages in the range can be dirty, clean or writeback.  We
 715          * start IO on any dirty ones so the wait doesn't stall waiting
 716          * for the flusher thread to find them
 717          */
 718         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 719                 filemap_fdatawrite_range(inode->i_mapping, start, end);
 720         if (wait) {
 721                 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 722                                                  &entry->flags));
 723         }
 724 }
 725
 726 /*
 727  * Used to wait on ordered extents across a large range of bytes.
 728  */
 729 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 730 {
 731         int ret = 0;
 732         int ret_wb = 0;
 733         u64 end;
 734         u64 orig_end;
 735         struct btrfs_ordered_extent *ordered;
 736
 737         if (start + len < start) {
 738                 orig_end = INT_LIMIT(loff_t);
 739         } else {
 740                 orig_end = start + len - 1;
 741                 if (orig_end > INT_LIMIT(loff_t))
 742                         orig_end = INT_LIMIT(loff_t);
 743         }
 744
 745         /* start IO across the range first to instantiate any delalloc
 746          * extents
 747          */
 748         ret = btrfs_fdatawrite_range(inode, start, orig_end);
 749         if (ret)
 750                 return ret;
 751
 752         /*
 753          * If we have a writeback error don't return immediately. Wait first
 754          * for any ordered extents that haven't completed yet. This is to make
 755          * sure no one can dirty the same page ranges and call writepages()
 756          * before the ordered extents complete - to avoid failures (-EEXIST)
 757          * when adding the new ordered extents to the ordered tree.
 758          */
 759         ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 760
 761         end = orig_end;
 762         while (1) {
 763                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
 764                 if (!ordered)
 765                         break;
 766                 if (ordered->file_offset > orig_end) {
 767                         btrfs_put_ordered_extent(ordered);
 768                         break;
 769                 }
 770                 if (ordered->file_offset + ordered->len <= start) {
 771                         btrfs_put_ordered_extent(ordered);
 772                         break;
 773                 }
 774                 btrfs_start_ordered_extent(inode, ordered, 1);
 775                 end = ordered->file_offset;
 776                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 777                         ret = -EIO;
 778                 btrfs_put_ordered_extent(ordered);
 779                 if (ret || end == 0 || end == start)
 780                         break;
 781                 end--;
 782         }
 783         return ret_wb ? ret_wb : ret;
 784 }
 785
 786 /*
 787  * find an ordered extent corresponding to file_offset.  return NULL if
 788  * nothing is found, otherwise take a reference on the extent and return it
 789  */
 790 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
 791                                                          u64 file_offset)
 792 {
 793         struct btrfs_ordered_inode_tree *tree;
 794         struct rb_node *node;
 795         struct btrfs_ordered_extent *entry = NULL;
 796
 797         tree = &BTRFS_I(inode)->ordered_tree;
 798         spin_lock_irq(&tree->lock);
 799         node = tree_search(tree, file_offset);
 800         if (!node)
 801                 goto out;
 802
 803         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 804         if (!offset_in_entry(entry, file_offset))
 805                 entry = NULL;
 806         if (entry)
 807                 atomic_inc(&entry->refs);
 808 out:
 809         spin_unlock_irq(&tree->lock);
 810         return entry;
 811 }
 812
 813 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 814  * extents that exist in the range, rather than just the start of the range.
 815  */
 816 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(struct inode *inode,
 817                                                         u64 file_offset,
 818                                                         u64 len)
 819 {
 820         struct btrfs_ordered_inode_tree *tree;
 821         struct rb_node *node;
 822         struct btrfs_ordered_extent *entry = NULL;
 823
 824         tree = &BTRFS_I(inode)->ordered_tree;
 825         spin_lock_irq(&tree->lock);
 826         node = tree_search(tree, file_offset);
 827         if (!node) {
 828                 node = tree_search(tree, file_offset + len);
 829                 if (!node)
 830                         goto out;
 831         }
 832
 833         while (1) {
 834                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 835                 if (range_overlaps(entry, file_offset, len))
 836                         break;
 837
 838                 if (entry->file_offset >= file_offset + len) {
 839                         entry = NULL;
 840                         break;
 841                 }
 842                 entry = NULL;
 843                 node = rb_next(node);
 844                 if (!node)
 845                         break;
 846         }
 847 out:
 848         if (entry)
 849                 atomic_inc(&entry->refs);
 850         spin_unlock_irq(&tree->lock);
 851         return entry;
 852 }
 853
 854 bool btrfs_have_ordered_extents_in_range(struct inode *inode,
 855                                          u64 file_offset,
 856                                          u64 len)
 857 {
 858         struct btrfs_ordered_extent *oe;
 859
 860         oe = btrfs_lookup_ordered_range(inode, file_offset, len);
 861         if (oe) {
 862                 btrfs_put_ordered_extent(oe);
 863                 return true;
 864         }
 865         return false;
 866 }
 867
 868 /*
 869  * lookup and return any extent before 'file_offset'.  NULL is returned
 870  * if none is found
 871  */
 872 struct btrfs_ordered_extent *
 873 btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
 874 {
 875         struct btrfs_ordered_inode_tree *tree;
 876         struct rb_node *node;
 877         struct btrfs_ordered_extent *entry = NULL;
 878
 879         tree = &BTRFS_I(inode)->ordered_tree;
 880         spin_lock_irq(&tree->lock);
 881         node = tree_search(tree, file_offset);
 882         if (!node)
 883                 goto out;
 884
 885         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 886         atomic_inc(&entry->refs);
 887 out:
 888         spin_unlock_irq(&tree->lock);
 889         return entry;
 890 }
 891
 892 /*
 893  * After an extent is done, call this to conditionally update the on disk
 894  * i_size.  i_size is updated to cover any fully written part of the file.
 895  */
 896 int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
 897                                 struct btrfs_ordered_extent *ordered)
 898 {
 899         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 900         u64 disk_i_size;
 901         u64 new_i_size;
 902         u64 i_size = i_size_read(inode);
 903         struct rb_node *node;
 904         struct rb_node *prev = NULL;
 905         struct btrfs_ordered_extent *test;
 906         int ret = 1;
 907
 908         spin_lock_irq(&tree->lock);
 909         if (ordered) {
 910                 offset = entry_end(ordered);
 911                 if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags))
 912                         offset = min(offset,
 913                                      ordered->file_offset +
 914                                      ordered->truncated_len);
 915         } else {
 916                 offset = ALIGN(offset, BTRFS_I(inode)->root->sectorsize);
 917         }
 918         disk_i_size = BTRFS_I(inode)->disk_i_size;
 919
 920         /* truncate file */
 921         if (disk_i_size > i_size) {
 922                 BTRFS_I(inode)->disk_i_size = i_size;
 923                 ret = 0;
 924                 goto out;
 925         }
 926
 927         /*
 928          * if the disk i_size is already at the inode->i_size, or
 929          * this ordered extent is inside the disk i_size, we're done
 930          */
 931         if (disk_i_size == i_size)
 932                 goto out;
 933
 934         /*
 935          * We still need to update disk_i_size if outstanding_isize is greater
 936          * than disk_i_size.
 937          */
 938         if (offset <= disk_i_size &&
 939             (!ordered || ordered->outstanding_isize <= disk_i_size))
 940                 goto out;
 941
 942         /*
 943          * walk backward from this ordered extent to disk_i_size.
 944          * if we find an ordered extent then we can't update disk i_size
 945          * yet
 946          */
 947         if (ordered) {
 948                 node = rb_prev(&ordered->rb_node);
 949         } else {
 950                 prev = tree_search(tree, offset);
 951                 /*
 952                  * we insert file extents without involving ordered struct,
 953                  * so there should be no ordered struct cover this offset
 954                  */
 955                 if (prev) {
 956                         test = rb_entry(prev, struct btrfs_ordered_extent,
 957                                         rb_node);
 958                         BUG_ON(offset_in_entry(test, offset));
 959                 }
 960                 node = prev;
 961         }
 962         for (; node; node = rb_prev(node)) {
 963                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 964
 965                 /* We treat this entry as if it doesnt exist */
 966                 if (test_bit(BTRFS_ORDERED_UPDATED_ISIZE, &test->flags))
 967                         continue;
 968                 if (test->file_offset + test->len <= disk_i_size)
 969                         break;
 970                 if (test->file_offset >= i_size)
 971                         break;
 972                 if (entry_end(test) > disk_i_size) {
 973                         /*
 974                          * we don't update disk_i_size now, so record this
 975                          * undealt i_size. Or we will not know the real
 976                          * i_size.
 977                          */
 978                         if (test->outstanding_isize < offset)
 979                                 test->outstanding_isize = offset;
 980                         if (ordered &&
 981                             ordered->outstanding_isize >
 982                             test->outstanding_isize)
 983                                 test->outstanding_isize =
 984                                                 ordered->outstanding_isize;
 985                         goto out;
 986                 }
 987         }
 988         new_i_size = min_t(u64, offset, i_size);
 989
 990         /*
 991          * Some ordered extents may completed before the current one, and
 992          * we hold the real i_size in ->outstanding_isize.
 993          */
 994         if (ordered && ordered->outstanding_isize > new_i_size)
 995                 new_i_size = min_t(u64, ordered->outstanding_isize, i_size);
 996         BTRFS_I(inode)->disk_i_size = new_i_size;
 997         ret = 0;
 998 out:
 999         /*
1000          * We need to do this because we can't remove ordered extents until
1001          * after the i_disk_size has been updated and then the inode has been
1002          * updated to reflect the change, so we need to tell anybody who finds
1003          * this ordered extent that we've already done all the real work, we
1004          * just haven't completed all the other work.
1005          */
1006         if (ordered)
1007                 set_bit(BTRFS_ORDERED_UPDATED_ISIZE, &ordered->flags);
1008         spin_unlock_irq(&tree->lock);
1009         return ret;
1010 }
1011
1012 /*
1013  * search the ordered extents for one corresponding to 'offset' and
1014  * try to find a checksum.  This is used because we allow pages to
1015  * be reclaimed before their checksum is actually put into the btree
1016  */
1017 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
1018                            u32 *sum, int len)
1019 {
1020         struct btrfs_ordered_sum *ordered_sum;
1021         struct btrfs_ordered_extent *ordered;
1022         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
1023         unsigned long num_sectors;
1024         unsigned long i;
1025         u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
1026         int index = 0;
1027
1028         ordered = btrfs_lookup_ordered_extent(inode, offset);
1029         if (!ordered)
1030                 return 0;
1031
1032         spin_lock_irq(&tree->lock);
1033         list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
1034                 if (disk_bytenr >= ordered_sum->bytenr &&
1035                     disk_bytenr < ordered_sum->bytenr + ordered_sum->len) {
1036                         i = (disk_bytenr - ordered_sum->bytenr) >>
1037                             inode->i_sb->s_blocksize_bits;
1038                         num_sectors = ordered_sum->len >>
1039                                       inode->i_sb->s_blocksize_bits;
1040                         num_sectors = min_t(int, len - index, num_sectors - i);
1041                         memcpy(sum + index, ordered_sum->sums + i,
1042                                num_sectors);
1043
1044                         index += (int)num_sectors;
1045                         if (index == len)
1046                                 goto out;
1047                         disk_bytenr += num_sectors * sectorsize;
1048                 }
1049         }
1050 out:
1051         spin_unlock_irq(&tree->lock);
1052         btrfs_put_ordered_extent(ordered);
1053         return index;
1054 }
1055
1056 int __init ordered_data_init(void)
1057 {
1058         btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
1059                                      sizeof(struct btrfs_ordered_extent), 0,
1060                                      SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
1061                                      NULL);
1062         if (!btrfs_ordered_extent_cache)
1063                 return -ENOMEM;
1064
1065         return 0;
1066 }
1067
1068 void ordered_data_exit(void)
1069 {
1070         if (btrfs_ordered_extent_cache)
1071                 kmem_cache_destroy(btrfs_ordered_extent_cache);
1072 }