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 #include "compression.h"
  29
  30 static struct kmem_cache *btrfs_ordered_extent_cache;
  31
  32 static u64 entry_end(struct btrfs_ordered_extent *entry)
  33 {
  34         if (entry->file_offset + entry->len < entry->file_offset)
  35                 return (u64)-1;
  36         return entry->file_offset + entry->len;
  37 }
  38
  39 /* returns NULL if the insertion worked, or it returns the node it did find
  40  * in the tree
  41  */
  42 static struct rb_node *tree_insert(struct rb_root *root, u64 file_offset,
  43                                    struct rb_node *node)
  44 {
  45         struct rb_node **p = &root->rb_node;
  46         struct rb_node *parent = NULL;
  47         struct btrfs_ordered_extent *entry;
  48
  49         while (*p) {
  50                 parent = *p;
  51                 entry = rb_entry(parent, struct btrfs_ordered_extent, rb_node);
  52
  53                 if (file_offset < entry->file_offset)
  54                         p = &(*p)->rb_left;
  55                 else if (file_offset >= entry_end(entry))
  56                         p = &(*p)->rb_right;
  57                 else
  58                         return parent;
  59         }
  60
  61         rb_link_node(node, parent, p);
  62         rb_insert_color(node, root);
  63         return NULL;
  64 }
  65
  66 static void ordered_data_tree_panic(struct inode *inode, int errno,
  67                                                u64 offset)
  68 {
  69         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
  70         btrfs_panic(fs_info, errno,
  71                     "Inconsistency in ordered tree at offset %llu", offset);
  72 }
  73
  74 /*
  75  * look for a given offset in the tree, and if it can't be found return the
  76  * first lesser offset
  77  */
  78 static struct rb_node *__tree_search(struct rb_root *root, u64 file_offset,
  79                                      struct rb_node **prev_ret)
  80 {
  81         struct rb_node *n = root->rb_node;
  82         struct rb_node *prev = NULL;
  83         struct rb_node *test;
  84         struct btrfs_ordered_extent *entry;
  85         struct btrfs_ordered_extent *prev_entry = NULL;
  86
  87         while (n) {
  88                 entry = rb_entry(n, struct btrfs_ordered_extent, rb_node);
  89                 prev = n;
  90                 prev_entry = entry;
  91
  92                 if (file_offset < entry->file_offset)
  93                         n = n->rb_left;
  94                 else if (file_offset >= entry_end(entry))
  95                         n = n->rb_right;
  96                 else
  97                         return n;
  98         }
  99         if (!prev_ret)
 100                 return NULL;
 101
 102         while (prev && file_offset >= entry_end(prev_entry)) {
 103                 test = rb_next(prev);
 104                 if (!test)
 105                         break;
 106                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 107                                       rb_node);
 108                 if (file_offset < entry_end(prev_entry))
 109                         break;
 110
 111                 prev = test;
 112         }
 113         if (prev)
 114                 prev_entry = rb_entry(prev, struct btrfs_ordered_extent,
 115                                       rb_node);
 116         while (prev && file_offset < entry_end(prev_entry)) {
 117                 test = rb_prev(prev);
 118                 if (!test)
 119                         break;
 120                 prev_entry = rb_entry(test, struct btrfs_ordered_extent,
 121                                       rb_node);
 122                 prev = test;
 123         }
 124         *prev_ret = prev;
 125         return NULL;
 126 }
 127
 128 /*
 129  * helper to check if a given offset is inside a given entry
 130  */
 131 static int offset_in_entry(struct btrfs_ordered_extent *entry, u64 file_offset)
 132 {
 133         if (file_offset < entry->file_offset ||
 134             entry->file_offset + entry->len <= file_offset)
 135                 return 0;
 136         return 1;
 137 }
 138
 139 static int range_overlaps(struct btrfs_ordered_extent *entry, u64 file_offset,
 140                           u64 len)
 141 {
 142         if (file_offset + len <= entry->file_offset ||
 143             entry->file_offset + entry->len <= file_offset)
 144                 return 0;
 145         return 1;
 146 }
 147
 148 /*
 149  * look find the first ordered struct that has this offset, otherwise
 150  * the first one less than this offset
 151  */
 152 static inline struct rb_node *tree_search(struct btrfs_ordered_inode_tree *tree,
 153                                           u64 file_offset)
 154 {
 155         struct rb_root *root = &tree->tree;
 156         struct rb_node *prev = NULL;
 157         struct rb_node *ret;
 158         struct btrfs_ordered_extent *entry;
 159
 160         if (tree->last) {
 161                 entry = rb_entry(tree->last, struct btrfs_ordered_extent,
 162                                  rb_node);
 163                 if (offset_in_entry(entry, file_offset))
 164                         return tree->last;
 165         }
 166         ret = __tree_search(root, file_offset, &prev);
 167         if (!ret)
 168                 ret = prev;
 169         if (ret)
 170                 tree->last = ret;
 171         return ret;
 172 }
 173
 174 /* allocate and add a new ordered_extent into the per-inode tree.
 175  * file_offset is the logical offset in the file
 176  *
 177  * start is the disk block number of an extent already reserved in the
 178  * extent allocation tree
 179  *
 180  * len is the length of the extent
 181  *
 182  * The tree is given a single reference on the ordered extent that was
 183  * inserted.
 184  */
 185 static int __btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 186                                       u64 start, u64 len, u64 disk_len,
 187                                       int type, int dio, int compress_type)
 188 {
 189         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 190         struct btrfs_root *root = BTRFS_I(inode)->root;
 191         struct btrfs_ordered_inode_tree *tree;
 192         struct rb_node *node;
 193         struct btrfs_ordered_extent *entry;
 194
 195         tree = &BTRFS_I(inode)->ordered_tree;
 196         entry = kmem_cache_zalloc(btrfs_ordered_extent_cache, GFP_NOFS);
 197         if (!entry)
 198                 return -ENOMEM;
 199
 200         entry->file_offset = file_offset;
 201         entry->start = start;
 202         entry->len = len;
 203         entry->disk_len = disk_len;
 204         entry->bytes_left = len;
 205         entry->inode = igrab(inode);
 206         entry->compress_type = compress_type;
 207         entry->truncated_len = (u64)-1;
 208         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 209                 set_bit(type, &entry->flags);
 210
 211         if (dio)
 212                 set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
 213
 214         /* one ref for the tree */
 215         refcount_set(&entry->refs, 1);
 216         init_waitqueue_head(&entry->wait);
 217         INIT_LIST_HEAD(&entry->list);
 218         INIT_LIST_HEAD(&entry->root_extent_list);
 219         INIT_LIST_HEAD(&entry->work_list);
 220         init_completion(&entry->completion);
 221         INIT_LIST_HEAD(&entry->log_list);
 222         INIT_LIST_HEAD(&entry->trans_list);
 223
 224         trace_btrfs_ordered_extent_add(inode, entry);
 225
 226         spin_lock_irq(&tree->lock);
 227         node = tree_insert(&tree->tree, file_offset,
 228                            &entry->rb_node);
 229         if (node)
 230                 ordered_data_tree_panic(inode, -EEXIST, file_offset);
 231         spin_unlock_irq(&tree->lock);
 232
 233         spin_lock(&root->ordered_extent_lock);
 234         list_add_tail(&entry->root_extent_list,
 235                       &root->ordered_extents);
 236         root->nr_ordered_extents++;
 237         if (root->nr_ordered_extents == 1) {
 238                 spin_lock(&fs_info->ordered_root_lock);
 239                 BUG_ON(!list_empty(&root->ordered_root));
 240                 list_add_tail(&root->ordered_root, &fs_info->ordered_roots);
 241                 spin_unlock(&fs_info->ordered_root_lock);
 242         }
 243         spin_unlock(&root->ordered_extent_lock);
 244
 245         /*
 246          * We don't need the count_max_extents here, we can assume that all of
 247          * that work has been done at higher layers, so this is truly the
 248          * smallest the extent is going to get.
 249          */
 250         spin_lock(&BTRFS_I(inode)->lock);
 251         btrfs_mod_outstanding_extents(BTRFS_I(inode), 1);
 252         spin_unlock(&BTRFS_I(inode)->lock);
 253
 254         return 0;
 255 }
 256
 257 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 258                              u64 start, u64 len, u64 disk_len, int type)
 259 {
 260         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 261                                           disk_len, type, 0,
 262                                           BTRFS_COMPRESS_NONE);
 263 }
 264
 265 int btrfs_add_ordered_extent_dio(struct inode *inode, u64 file_offset,
 266                                  u64 start, u64 len, u64 disk_len, int type)
 267 {
 268         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 269                                           disk_len, type, 1,
 270                                           BTRFS_COMPRESS_NONE);
 271 }
 272
 273 int btrfs_add_ordered_extent_compress(struct inode *inode, u64 file_offset,
 274                                       u64 start, u64 len, u64 disk_len,
 275                                       int type, int compress_type)
 276 {
 277         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 278                                           disk_len, type, 0,
 279                                           compress_type);
 280 }
 281
 282 /*
 283  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 284  * when an ordered extent is finished.  If the list covers more than one
 285  * ordered extent, it is split across multiples.
 286  */
 287 void btrfs_add_ordered_sum(struct inode *inode,
 288                            struct btrfs_ordered_extent *entry,
 289                            struct btrfs_ordered_sum *sum)
 290 {
 291         struct btrfs_ordered_inode_tree *tree;
 292
 293         tree = &BTRFS_I(inode)->ordered_tree;
 294         spin_lock_irq(&tree->lock);
 295         list_add_tail(&sum->list, &entry->list);
 296         spin_unlock_irq(&tree->lock);
 297 }
 298
 299 /*
 300  * this is used to account for finished IO across a given range
 301  * of the file.  The IO may span ordered extents.  If
 302  * a given ordered_extent is completely done, 1 is returned, otherwise
 303  * 0.
 304  *
 305  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 306  * to make sure this function only returns 1 once for a given ordered extent.
 307  *
 308  * file_offset is updated to one byte past the range that is recorded as
 309  * complete.  This allows you to walk forward in the file.
 310  */
 311 int btrfs_dec_test_first_ordered_pending(struct inode *inode,
 312                                    struct btrfs_ordered_extent **cached,
 313                                    u64 *file_offset, u64 io_size, int uptodate)
 314 {
 315         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 316         struct btrfs_ordered_inode_tree *tree;
 317         struct rb_node *node;
 318         struct btrfs_ordered_extent *entry = NULL;
 319         int ret;
 320         unsigned long flags;
 321         u64 dec_end;
 322         u64 dec_start;
 323         u64 to_dec;
 324
 325         tree = &BTRFS_I(inode)->ordered_tree;
 326         spin_lock_irqsave(&tree->lock, flags);
 327         node = tree_search(tree, *file_offset);
 328         if (!node) {
 329                 ret = 1;
 330                 goto out;
 331         }
 332
 333         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 334         if (!offset_in_entry(entry, *file_offset)) {
 335                 ret = 1;
 336                 goto out;
 337         }
 338
 339         dec_start = max(*file_offset, entry->file_offset);
 340         dec_end = min(*file_offset + io_size, entry->file_offset +
 341                       entry->len);
 342         *file_offset = dec_end;
 343         if (dec_start > dec_end) {
 344                 btrfs_crit(fs_info, "bad ordering dec_start %llu end %llu",
 345                            dec_start, dec_end);
 346         }
 347         to_dec = dec_end - dec_start;
 348         if (to_dec > entry->bytes_left) {
 349                 btrfs_crit(fs_info,
 350                            "bad ordered accounting left %llu size %llu",
 351                            entry->bytes_left, to_dec);
 352         }
 353         entry->bytes_left -= to_dec;
 354         if (!uptodate)
 355                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 356
 357         if (entry->bytes_left == 0) {
 358                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 359                 /*
 360                  * Implicit memory barrier after test_and_set_bit
 361                  */
 362                 if (waitqueue_active(&entry->wait))
 363                         wake_up(&entry->wait);
 364         } else {
 365                 ret = 1;
 366         }
 367 out:
 368         if (!ret && cached && entry) {
 369                 *cached = entry;
 370                 refcount_inc(&entry->refs);
 371         }
 372         spin_unlock_irqrestore(&tree->lock, flags);
 373         return ret == 0;
 374 }
 375
 376 /*
 377  * this is used to account for finished IO across a given range
 378  * of the file.  The IO should not span ordered extents.  If
 379  * a given ordered_extent is completely done, 1 is returned, otherwise
 380  * 0.
 381  *
 382  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 383  * to make sure this function only returns 1 once for a given ordered extent.
 384  */
 385 int btrfs_dec_test_ordered_pending(struct inode *inode,
 386                                    struct btrfs_ordered_extent **cached,
 387                                    u64 file_offset, u64 io_size, int uptodate)
 388 {
 389         struct btrfs_ordered_inode_tree *tree;
 390         struct rb_node *node;
 391         struct btrfs_ordered_extent *entry = NULL;
 392         unsigned long flags;
 393         int ret;
 394
 395         tree = &BTRFS_I(inode)->ordered_tree;
 396         spin_lock_irqsave(&tree->lock, flags);
 397         if (cached && *cached) {
 398                 entry = *cached;
 399                 goto have_entry;
 400         }
 401
 402         node = tree_search(tree, file_offset);
 403         if (!node) {
 404                 ret = 1;
 405                 goto out;
 406         }
 407
 408         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 409 have_entry:
 410         if (!offset_in_entry(entry, file_offset)) {
 411                 ret = 1;
 412                 goto out;
 413         }
 414
 415         if (io_size > entry->bytes_left) {
 416                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
 417                            "bad ordered accounting left %llu size %llu",
 418                        entry->bytes_left, io_size);
 419         }
 420         entry->bytes_left -= io_size;
 421         if (!uptodate)
 422                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 423
 424         if (entry->bytes_left == 0) {
 425                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 426                 /*
 427                  * Implicit memory barrier after test_and_set_bit
 428                  */
 429                 if (waitqueue_active(&entry->wait))
 430                         wake_up(&entry->wait);
 431         } else {
 432                 ret = 1;
 433         }
 434 out:
 435         if (!ret && cached && entry) {
 436                 *cached = entry;
 437                 refcount_inc(&entry->refs);
 438         }
 439         spin_unlock_irqrestore(&tree->lock, flags);
 440         return ret == 0;
 441 }
 442
 443 /* Needs to either be called under a log transaction or the log_mutex */
 444 void btrfs_get_logged_extents(struct btrfs_inode *inode,
 445                               struct list_head *logged_list,
 446                               const loff_t start,
 447                               const loff_t end)
 448 {
 449         struct btrfs_ordered_inode_tree *tree;
 450         struct btrfs_ordered_extent *ordered;
 451         struct rb_node *n;
 452         struct rb_node *prev;
 453
 454         tree = &inode->ordered_tree;
 455         spin_lock_irq(&tree->lock);
 456         n = __tree_search(&tree->tree, end, &prev);
 457         if (!n)
 458                 n = prev;
 459         for (; n; n = rb_prev(n)) {
 460                 ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
 461                 if (ordered->file_offset > end)
 462                         continue;
 463                 if (entry_end(ordered) <= start)
 464                         break;
 465                 if (test_and_set_bit(BTRFS_ORDERED_LOGGED, &ordered->flags))
 466                         continue;
 467                 list_add(&ordered->log_list, logged_list);
 468                 refcount_inc(&ordered->refs);
 469         }
 470         spin_unlock_irq(&tree->lock);
 471 }
 472
 473 void btrfs_put_logged_extents(struct list_head *logged_list)
 474 {
 475         struct btrfs_ordered_extent *ordered;
 476
 477         while (!list_empty(logged_list)) {
 478                 ordered = list_first_entry(logged_list,
 479                                            struct btrfs_ordered_extent,
 480                                            log_list);
 481                 list_del_init(&ordered->log_list);
 482                 btrfs_put_ordered_extent(ordered);
 483         }
 484 }
 485
 486 void btrfs_submit_logged_extents(struct list_head *logged_list,
 487                                  struct btrfs_root *log)
 488 {
 489         int index = log->log_transid % 2;
 490
 491         spin_lock_irq(&log->log_extents_lock[index]);
 492         list_splice_tail(logged_list, &log->logged_list[index]);
 493         spin_unlock_irq(&log->log_extents_lock[index]);
 494 }
 495
 496 void btrfs_wait_logged_extents(struct btrfs_trans_handle *trans,
 497                                struct btrfs_root *log, u64 transid)
 498 {
 499         struct btrfs_ordered_extent *ordered;
 500         int index = transid % 2;
 501
 502         spin_lock_irq(&log->log_extents_lock[index]);
 503         while (!list_empty(&log->logged_list[index])) {
 504                 struct inode *inode;
 505                 ordered = list_first_entry(&log->logged_list[index],
 506                                            struct btrfs_ordered_extent,
 507                                            log_list);
 508                 list_del_init(&ordered->log_list);
 509                 inode = ordered->inode;
 510                 spin_unlock_irq(&log->log_extents_lock[index]);
 511
 512                 if (!test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags) &&
 513                     !test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags)) {
 514                         u64 start = ordered->file_offset;
 515                         u64 end = ordered->file_offset + ordered->len - 1;
 516
 517                         WARN_ON(!inode);
 518                         filemap_fdatawrite_range(inode->i_mapping, start, end);
 519                 }
 520                 wait_event(ordered->wait, test_bit(BTRFS_ORDERED_IO_DONE,
 521                                                    &ordered->flags));
 522
 523                 /*
 524                  * In order to keep us from losing our ordered extent
 525                  * information when committing the transaction we have to make
 526                  * sure that any logged extents are completed when we go to
 527                  * commit the transaction.  To do this we simply increase the
 528                  * current transactions pending_ordered counter and decrement it
 529                  * when the ordered extent completes.
 530                  */
 531                 if (!test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) {
 532                         struct btrfs_ordered_inode_tree *tree;
 533
 534                         tree = &BTRFS_I(inode)->ordered_tree;
 535                         spin_lock_irq(&tree->lock);
 536                         if (!test_bit(BTRFS_ORDERED_COMPLETE, &ordered->flags)) {
 537                                 set_bit(BTRFS_ORDERED_PENDING, &ordered->flags);
 538                                 atomic_inc(&trans->transaction->pending_ordered);
 539                         }
 540                         spin_unlock_irq(&tree->lock);
 541                 }
 542                 btrfs_put_ordered_extent(ordered);
 543                 spin_lock_irq(&log->log_extents_lock[index]);
 544         }
 545         spin_unlock_irq(&log->log_extents_lock[index]);
 546 }
 547
 548 void btrfs_free_logged_extents(struct btrfs_root *log, u64 transid)
 549 {
 550         struct btrfs_ordered_extent *ordered;
 551         int index = transid % 2;
 552
 553         spin_lock_irq(&log->log_extents_lock[index]);
 554         while (!list_empty(&log->logged_list[index])) {
 555                 ordered = list_first_entry(&log->logged_list[index],
 556                                            struct btrfs_ordered_extent,
 557                                            log_list);
 558                 list_del_init(&ordered->log_list);
 559                 spin_unlock_irq(&log->log_extents_lock[index]);
 560                 btrfs_put_ordered_extent(ordered);
 561                 spin_lock_irq(&log->log_extents_lock[index]);
 562         }
 563         spin_unlock_irq(&log->log_extents_lock[index]);
 564 }
 565
 566 /*
 567  * used to drop a reference on an ordered extent.  This will free
 568  * the extent if the last reference is dropped
 569  */
 570 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 571 {
 572         struct list_head *cur;
 573         struct btrfs_ordered_sum *sum;
 574
 575         trace_btrfs_ordered_extent_put(entry->inode, entry);
 576
 577         if (refcount_dec_and_test(&entry->refs)) {
 578                 ASSERT(list_empty(&entry->log_list));
 579                 ASSERT(list_empty(&entry->trans_list));
 580                 ASSERT(list_empty(&entry->root_extent_list));
 581                 ASSERT(RB_EMPTY_NODE(&entry->rb_node));
 582                 if (entry->inode)
 583                         btrfs_add_delayed_iput(entry->inode);
 584                 while (!list_empty(&entry->list)) {
 585                         cur = entry->list.next;
 586                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 587                         list_del(&sum->list);
 588                         kfree(sum);
 589                 }
 590                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
 591         }
 592 }
 593
 594 /*
 595  * remove an ordered extent from the tree.  No references are dropped
 596  * and waiters are woken up.
 597  */
 598 void btrfs_remove_ordered_extent(struct inode *inode,
 599                                  struct btrfs_ordered_extent *entry)
 600 {
 601         struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
 602         struct btrfs_ordered_inode_tree *tree;
 603         struct btrfs_inode *btrfs_inode = BTRFS_I(inode);
 604         struct btrfs_root *root = btrfs_inode->root;
 605         struct rb_node *node;
 606         bool dec_pending_ordered = false;
 607
 608         /* This is paired with btrfs_add_ordered_extent. */
 609         spin_lock(&btrfs_inode->lock);
 610         btrfs_mod_outstanding_extents(btrfs_inode, -1);
 611         spin_unlock(&btrfs_inode->lock);
 612         if (root != fs_info->tree_root)
 613                 btrfs_delalloc_release_metadata(btrfs_inode, entry->len);
 614
 615         tree = &btrfs_inode->ordered_tree;
 616         spin_lock_irq(&tree->lock);
 617         node = &entry->rb_node;
 618         rb_erase(node, &tree->tree);
 619         RB_CLEAR_NODE(node);
 620         if (tree->last == node)
 621                 tree->last = NULL;
 622         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 623         if (test_and_clear_bit(BTRFS_ORDERED_PENDING, &entry->flags))
 624                 dec_pending_ordered = true;
 625         spin_unlock_irq(&tree->lock);
 626
 627         /*
 628          * The current running transaction is waiting on us, we need to let it
 629          * know that we're complete and wake it up.
 630          */
 631         if (dec_pending_ordered) {
 632                 struct btrfs_transaction *trans;
 633
 634                 /*
 635                  * The checks for trans are just a formality, it should be set,
 636                  * but if it isn't we don't want to deref/assert under the spin
 637                  * lock, so be nice and check if trans is set, but ASSERT() so
 638                  * if it isn't set a developer will notice.
 639                  */
 640                 spin_lock(&fs_info->trans_lock);
 641                 trans = fs_info->running_transaction;
 642                 if (trans)
 643                         refcount_inc(&trans->use_count);
 644                 spin_unlock(&fs_info->trans_lock);
 645
 646                 ASSERT(trans);
 647                 if (trans) {
 648                         if (atomic_dec_and_test(&trans->pending_ordered))
 649                                 wake_up(&trans->pending_wait);
 650                         btrfs_put_transaction(trans);
 651                 }
 652         }
 653
 654         spin_lock(&root->ordered_extent_lock);
 655         list_del_init(&entry->root_extent_list);
 656         root->nr_ordered_extents--;
 657
 658         trace_btrfs_ordered_extent_remove(inode, entry);
 659
 660         if (!root->nr_ordered_extents) {
 661                 spin_lock(&fs_info->ordered_root_lock);
 662                 BUG_ON(list_empty(&root->ordered_root));
 663                 list_del_init(&root->ordered_root);
 664                 spin_unlock(&fs_info->ordered_root_lock);
 665         }
 666         spin_unlock(&root->ordered_extent_lock);
 667         wake_up(&entry->wait);
 668 }
 669
 670 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 671 {
 672         struct btrfs_ordered_extent *ordered;
 673
 674         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 675         btrfs_start_ordered_extent(ordered->inode, ordered, 1);
 676         complete(&ordered->completion);
 677 }
 678
 679 /*
 680  * wait for all the ordered extents in a root.  This is done when balancing
 681  * space between drives.
 682  */
 683 u64 btrfs_wait_ordered_extents(struct btrfs_root *root, u64 nr,
 684                                const u64 range_start, const u64 range_len)
 685 {
 686         struct btrfs_fs_info *fs_info = root->fs_info;
 687         LIST_HEAD(splice);
 688         LIST_HEAD(skipped);
 689         LIST_HEAD(works);
 690         struct btrfs_ordered_extent *ordered, *next;
 691         u64 count = 0;
 692         const u64 range_end = range_start + range_len;
 693
 694         mutex_lock(&root->ordered_extent_mutex);
 695         spin_lock(&root->ordered_extent_lock);
 696         list_splice_init(&root->ordered_extents, &splice);
 697         while (!list_empty(&splice) && nr) {
 698                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 699                                            root_extent_list);
 700
 701                 if (range_end <= ordered->start ||
 702                     ordered->start + ordered->disk_len <= range_start) {
 703                         list_move_tail(&ordered->root_extent_list, &skipped);
 704                         cond_resched_lock(&root->ordered_extent_lock);
 705                         continue;
 706                 }
 707
 708                 list_move_tail(&ordered->root_extent_list,
 709                                &root->ordered_extents);
 710                 refcount_inc(&ordered->refs);
 711                 spin_unlock(&root->ordered_extent_lock);
 712
 713                 btrfs_init_work(&ordered->flush_work,
 714                                 btrfs_flush_delalloc_helper,
 715                                 btrfs_run_ordered_extent_work, NULL, NULL);
 716                 list_add_tail(&ordered->work_list, &works);
 717                 btrfs_queue_work(fs_info->flush_workers, &ordered->flush_work);
 718
 719                 cond_resched();
 720                 spin_lock(&root->ordered_extent_lock);
 721                 if (nr != U64_MAX)
 722                         nr--;
 723                 count++;
 724         }
 725         list_splice_tail(&skipped, &root->ordered_extents);
 726         list_splice_tail(&splice, &root->ordered_extents);
 727         spin_unlock(&root->ordered_extent_lock);
 728
 729         list_for_each_entry_safe(ordered, next, &works, work_list) {
 730                 list_del_init(&ordered->work_list);
 731                 wait_for_completion(&ordered->completion);
 732                 btrfs_put_ordered_extent(ordered);
 733                 cond_resched();
 734         }
 735         mutex_unlock(&root->ordered_extent_mutex);
 736
 737         return count;
 738 }
 739
 740 u64 btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, u64 nr,
 741                              const u64 range_start, const u64 range_len)
 742 {
 743         struct btrfs_root *root;
 744         struct list_head splice;
 745         u64 total_done = 0;
 746         u64 done;
 747
 748         INIT_LIST_HEAD(&splice);
 749
 750         mutex_lock(&fs_info->ordered_operations_mutex);
 751         spin_lock(&fs_info->ordered_root_lock);
 752         list_splice_init(&fs_info->ordered_roots, &splice);
 753         while (!list_empty(&splice) && nr) {
 754                 root = list_first_entry(&splice, struct btrfs_root,
 755                                         ordered_root);
 756                 root = btrfs_grab_fs_root(root);
 757                 BUG_ON(!root);
 758                 list_move_tail(&root->ordered_root,
 759                                &fs_info->ordered_roots);
 760                 spin_unlock(&fs_info->ordered_root_lock);
 761
 762                 done = btrfs_wait_ordered_extents(root, nr,
 763                                                   range_start, range_len);
 764                 btrfs_put_fs_root(root);
 765                 total_done += done;
 766
 767                 spin_lock(&fs_info->ordered_root_lock);
 768                 if (nr != U64_MAX) {
 769                         nr -= done;
 770                 }
 771         }
 772         list_splice_tail(&splice, &fs_info->ordered_roots);
 773         spin_unlock(&fs_info->ordered_root_lock);
 774         mutex_unlock(&fs_info->ordered_operations_mutex);
 775
 776         return total_done;
 777 }
 778
 779 /*
 780  * Used to start IO or wait for a given ordered extent to finish.
 781  *
 782  * If wait is one, this effectively waits on page writeback for all the pages
 783  * in the extent, and it waits on the io completion code to insert
 784  * metadata into the btree corresponding to the extent
 785  */
 786 void btrfs_start_ordered_extent(struct inode *inode,
 787                                        struct btrfs_ordered_extent *entry,
 788                                        int wait)
 789 {
 790         u64 start = entry->file_offset;
 791         u64 end = start + entry->len - 1;
 792
 793         trace_btrfs_ordered_extent_start(inode, entry);
 794
 795         /*
 796          * pages in the range can be dirty, clean or writeback.  We
 797          * start IO on any dirty ones so the wait doesn't stall waiting
 798          * for the flusher thread to find them
 799          */
 800         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 801                 filemap_fdatawrite_range(inode->i_mapping, start, end);
 802         if (wait) {
 803                 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 804                                                  &entry->flags));
 805         }
 806 }
 807
 808 /*
 809  * Used to wait on ordered extents across a large range of bytes.
 810  */
 811 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 812 {
 813         int ret = 0;
 814         int ret_wb = 0;
 815         u64 end;
 816         u64 orig_end;
 817         struct btrfs_ordered_extent *ordered;
 818
 819         if (start + len < start) {
 820                 orig_end = INT_LIMIT(loff_t);
 821         } else {
 822                 orig_end = start + len - 1;
 823                 if (orig_end > INT_LIMIT(loff_t))
 824                         orig_end = INT_LIMIT(loff_t);
 825         }
 826
 827         /* start IO across the range first to instantiate any delalloc
 828          * extents
 829          */
 830         ret = btrfs_fdatawrite_range(inode, start, orig_end);
 831         if (ret)
 832                 return ret;
 833
 834         /*
 835          * If we have a writeback error don't return immediately. Wait first
 836          * for any ordered extents that haven't completed yet. This is to make
 837          * sure no one can dirty the same page ranges and call writepages()
 838          * before the ordered extents complete - to avoid failures (-EEXIST)
 839          * when adding the new ordered extents to the ordered tree.
 840          */
 841         ret_wb = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 842
 843         end = orig_end;
 844         while (1) {
 845                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
 846                 if (!ordered)
 847                         break;
 848                 if (ordered->file_offset > orig_end) {
 849                         btrfs_put_ordered_extent(ordered);
 850                         break;
 851                 }
 852                 if (ordered->file_offset + ordered->len <= start) {
 853                         btrfs_put_ordered_extent(ordered);
 854                         break;
 855                 }
 856                 btrfs_start_ordered_extent(inode, ordered, 1);
 857                 end = ordered->file_offset;
 858                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 859                         ret = -EIO;
 860                 btrfs_put_ordered_extent(ordered);
 861                 if (ret || end == 0 || end == start)
 862                         break;
 863                 end--;
 864         }
 865         return ret_wb ? ret_wb : ret;
 866 }
 867
 868 /*
 869  * find an ordered extent corresponding to file_offset.  return NULL if
 870  * nothing is found, otherwise take a reference on the extent and return it
 871  */
 872 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
 873                                                          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         if (!offset_in_entry(entry, file_offset))
 887                 entry = NULL;
 888         if (entry)
 889                 refcount_inc(&entry->refs);
 890 out:
 891         spin_unlock_irq(&tree->lock);
 892         return entry;
 893 }
 894
 895 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 896  * extents that exist in the range, rather than just the start of the range.
 897  */
 898 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(
 899                 struct btrfs_inode *inode, u64 file_offset, u64 len)
 900 {
 901         struct btrfs_ordered_inode_tree *tree;
 902         struct rb_node *node;
 903         struct btrfs_ordered_extent *entry = NULL;
 904
 905         tree = &inode->ordered_tree;
 906         spin_lock_irq(&tree->lock);
 907         node = tree_search(tree, file_offset);
 908         if (!node) {
 909                 node = tree_search(tree, file_offset + len);
 910                 if (!node)
 911                         goto out;
 912         }
 913
 914         while (1) {
 915                 entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 916                 if (range_overlaps(entry, file_offset, len))
 917                         break;
 918
 919                 if (entry->file_offset >= file_offset + len) {
 920                         entry = NULL;
 921                         break;
 922                 }
 923                 entry = NULL;
 924                 node = rb_next(node);
 925                 if (!node)
 926                         break;
 927         }
 928 out:
 929         if (entry)
 930                 refcount_inc(&entry->refs);
 931         spin_unlock_irq(&tree->lock);
 932         return entry;
 933 }
 934
 935 bool btrfs_have_ordered_extents_in_range(struct inode *inode,
 936                                          u64 file_offset,
 937                                          u64 len)
 938 {
 939         struct btrfs_ordered_extent *oe;
 940
 941         oe = btrfs_lookup_ordered_range(BTRFS_I(inode), file_offset, len);
 942         if (oe) {
 943                 btrfs_put_ordered_extent(oe);
 944                 return true;
 945         }
 946         return false;
 947 }
 948
 949 /*
 950  * lookup and return any extent before 'file_offset'.  NULL is returned
 951  * if none is found
 952  */
 953 struct btrfs_ordered_extent *
 954 btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
 955 {
 956         struct btrfs_ordered_inode_tree *tree;
 957         struct rb_node *node;
 958         struct btrfs_ordered_extent *entry = NULL;
 959
 960         tree = &BTRFS_I(inode)->ordered_tree;
 961         spin_lock_irq(&tree->lock);
 962         node = tree_search(tree, file_offset);
 963         if (!node)
 964                 goto out;
 965
 966         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 967         refcount_inc(&entry->refs);
 968 out:
 969         spin_unlock_irq(&tree->lock);
 970         return entry;
 971 }
 972
 973 /*
 974  * After an extent is done, call this to conditionally update the on disk
 975  * i_size.  i_size is updated to cover any fully written part of the file.
 976  */
 977 int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
 978                                 struct btrfs_ordered_extent *ordered)
 979 {
 980         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 981         u64 disk_i_size;
 982         u64 new_i_size;
 983         u64 i_size = i_size_read(inode);
 984         struct rb_node *node;
 985         struct rb_node *prev = NULL;
 986         struct btrfs_ordered_extent *test;
 987         int ret = 1;
 988         u64 orig_offset = offset;
 989
 990         spin_lock_irq(&tree->lock);
 991         if (ordered) {
 992                 offset = entry_end(ordered);
 993                 if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags))
 994                         offset = min(offset,
 995                                      ordered->file_offset +
 996                                      ordered->truncated_len);
 997         } else {
 998                 offset = ALIGN(offset, btrfs_inode_sectorsize(inode));
 999         }
1000         disk_i_size = BTRFS_I(inode)->disk_i_size;
1001
1002         /*
1003          * truncate file.
1004          * If ordered is not NULL, then this is called from endio and
1005          * disk_i_size will be updated by either truncate itself or any
1006          * in-flight IOs which are inside the disk_i_size.
1007          *
1008          * Because btrfs_setsize() may set i_size with disk_i_size if truncate
1009          * fails somehow, we need to make sure we have a precise disk_i_size by
1010          * updating it as usual.
1011          *
1012          */
1013         if (!ordered && disk_i_size > i_size) {
1014                 BTRFS_I(inode)->disk_i_size = orig_offset;
1015                 ret = 0;
1016                 goto out;
1017         }
1018
1019         /*
1020          * if the disk i_size is already at the inode->i_size, or
1021          * this ordered extent is inside the disk i_size, we're done
1022          */
1023         if (disk_i_size == i_size)
1024                 goto out;
1025
1026         /*
1027          * We still need to update disk_i_size if outstanding_isize is greater
1028          * than disk_i_size.
1029          */
1030         if (offset <= disk_i_size &&
1031             (!ordered || ordered->outstanding_isize <= disk_i_size))
1032                 goto out;
1033
1034         /*
1035          * walk backward from this ordered extent to disk_i_size.
1036          * if we find an ordered extent then we can't update disk i_size
1037          * yet
1038          */
1039         if (ordered) {
1040                 node = rb_prev(&ordered->rb_node);
1041         } else {
1042                 prev = tree_search(tree, offset);
1043                 /*
1044                  * we insert file extents without involving ordered struct,
1045                  * so there should be no ordered struct cover this offset
1046                  */
1047                 if (prev) {
1048                         test = rb_entry(prev, struct btrfs_ordered_extent,
1049                                         rb_node);
1050                         BUG_ON(offset_in_entry(test, offset));
1051                 }
1052                 node = prev;
1053         }
1054         for (; node; node = rb_prev(node)) {
1055                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
1056
1057                 /* We treat this entry as if it doesn't exist */
1058                 if (test_bit(BTRFS_ORDERED_UPDATED_ISIZE, &test->flags))
1059                         continue;
1060
1061                 if (entry_end(test) <= disk_i_size)
1062                         break;
1063                 if (test->file_offset >= i_size)
1064                         break;
1065
1066                 /*
1067                  * We don't update disk_i_size now, so record this undealt
1068                  * i_size. Or we will not know the real i_size.
1069                  */
1070                 if (test->outstanding_isize < offset)
1071                         test->outstanding_isize = offset;
1072                 if (ordered &&
1073                     ordered->outstanding_isize > test->outstanding_isize)
1074                         test->outstanding_isize = ordered->outstanding_isize;
1075                 goto out;
1076         }
1077         new_i_size = min_t(u64, offset, i_size);
1078
1079         /*
1080          * Some ordered extents may completed before the current one, and
1081          * we hold the real i_size in ->outstanding_isize.
1082          */
1083         if (ordered && ordered->outstanding_isize > new_i_size)
1084                 new_i_size = min_t(u64, ordered->outstanding_isize, i_size);
1085         BTRFS_I(inode)->disk_i_size = new_i_size;
1086         ret = 0;
1087 out:
1088         /*
1089          * We need to do this because we can't remove ordered extents until
1090          * after the i_disk_size has been updated and then the inode has been
1091          * updated to reflect the change, so we need to tell anybody who finds
1092          * this ordered extent that we've already done all the real work, we
1093          * just haven't completed all the other work.
1094          */
1095         if (ordered)
1096                 set_bit(BTRFS_ORDERED_UPDATED_ISIZE, &ordered->flags);
1097         spin_unlock_irq(&tree->lock);
1098         return ret;
1099 }
1100
1101 /*
1102  * search the ordered extents for one corresponding to 'offset' and
1103  * try to find a checksum.  This is used because we allow pages to
1104  * be reclaimed before their checksum is actually put into the btree
1105  */
1106 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
1107                            u32 *sum, int len)
1108 {
1109         struct btrfs_ordered_sum *ordered_sum;
1110         struct btrfs_ordered_extent *ordered;
1111         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
1112         unsigned long num_sectors;
1113         unsigned long i;
1114         u32 sectorsize = btrfs_inode_sectorsize(inode);
1115         int index = 0;
1116
1117         ordered = btrfs_lookup_ordered_extent(inode, offset);
1118         if (!ordered)
1119                 return 0;
1120
1121         spin_lock_irq(&tree->lock);
1122         list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
1123                 if (disk_bytenr >= ordered_sum->bytenr &&
1124                     disk_bytenr < ordered_sum->bytenr + ordered_sum->len) {
1125                         i = (disk_bytenr - ordered_sum->bytenr) >>
1126                             inode->i_sb->s_blocksize_bits;
1127                         num_sectors = ordered_sum->len >>
1128                                       inode->i_sb->s_blocksize_bits;
1129                         num_sectors = min_t(int, len - index, num_sectors - i);
1130                         memcpy(sum + index, ordered_sum->sums + i,
1131                                num_sectors);
1132
1133                         index += (int)num_sectors;
1134                         if (index == len)
1135                                 goto out;
1136                         disk_bytenr += num_sectors * sectorsize;
1137                 }
1138         }
1139 out:
1140         spin_unlock_irq(&tree->lock);
1141         btrfs_put_ordered_extent(ordered);
1142         return index;
1143 }
1144
1145 int __init ordered_data_init(void)
1146 {
1147         btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
1148                                      sizeof(struct btrfs_ordered_extent), 0,
1149                                      SLAB_MEM_SPREAD,
1150                                      NULL);
1151         if (!btrfs_ordered_extent_cache)
1152                 return -ENOMEM;
1153
1154         return 0;
1155 }
1156
1157 void ordered_data_exit(void)
1158 {
1159         kmem_cache_destroy(btrfs_ordered_extent_cache);
1160 }