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         if (!(BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) &&
 202             !(type == BTRFS_ORDERED_NOCOW))
 203                 entry->csum_bytes_left = disk_len;
 204         entry->disk_len = disk_len;
 205         entry->bytes_left = len;
 206         entry->inode = igrab(inode);
 207         entry->compress_type = compress_type;
 208         entry->truncated_len = (u64)-1;
 209         if (type != BTRFS_ORDERED_IO_DONE && type != BTRFS_ORDERED_COMPLETE)
 210                 set_bit(type, &entry->flags);
 211
 212         if (dio)
 213                 set_bit(BTRFS_ORDERED_DIRECT, &entry->flags);
 214
 215         /* one ref for the tree */
 216         atomic_set(&entry->refs, 1);
 217         init_waitqueue_head(&entry->wait);
 218         INIT_LIST_HEAD(&entry->list);
 219         INIT_LIST_HEAD(&entry->root_extent_list);
 220         INIT_LIST_HEAD(&entry->work_list);
 221         init_completion(&entry->completion);
 222         INIT_LIST_HEAD(&entry->log_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(&root->fs_info->ordered_root_lock);
 239                 BUG_ON(!list_empty(&root->ordered_root));
 240                 list_add_tail(&root->ordered_root,
 241                               &root->fs_info->ordered_roots);
 242                 spin_unlock(&root->fs_info->ordered_root_lock);
 243         }
 244         spin_unlock(&root->ordered_extent_lock);
 245
 246         return 0;
 247 }
 248
 249 int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset,
 250                              u64 start, u64 len, u64 disk_len, int type)
 251 {
 252         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 253                                           disk_len, type, 0,
 254                                           BTRFS_COMPRESS_NONE);
 255 }
 256
 257 int btrfs_add_ordered_extent_dio(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, 1,
 262                                           BTRFS_COMPRESS_NONE);
 263 }
 264
 265 int btrfs_add_ordered_extent_compress(struct inode *inode, u64 file_offset,
 266                                       u64 start, u64 len, u64 disk_len,
 267                                       int type, int compress_type)
 268 {
 269         return __btrfs_add_ordered_extent(inode, file_offset, start, len,
 270                                           disk_len, type, 0,
 271                                           compress_type);
 272 }
 273
 274 /*
 275  * Add a struct btrfs_ordered_sum into the list of checksums to be inserted
 276  * when an ordered extent is finished.  If the list covers more than one
 277  * ordered extent, it is split across multiples.
 278  */
 279 void btrfs_add_ordered_sum(struct inode *inode,
 280                            struct btrfs_ordered_extent *entry,
 281                            struct btrfs_ordered_sum *sum)
 282 {
 283         struct btrfs_ordered_inode_tree *tree;
 284
 285         tree = &BTRFS_I(inode)->ordered_tree;
 286         spin_lock_irq(&tree->lock);
 287         list_add_tail(&sum->list, &entry->list);
 288         WARN_ON(entry->csum_bytes_left < sum->len);
 289         entry->csum_bytes_left -= sum->len;
 290         if (entry->csum_bytes_left == 0)
 291                 wake_up(&entry->wait);
 292         spin_unlock_irq(&tree->lock);
 293 }
 294
 295 /*
 296  * this is used to account for finished IO across a given range
 297  * of the file.  The IO may span ordered extents.  If
 298  * a given ordered_extent is completely done, 1 is returned, otherwise
 299  * 0.
 300  *
 301  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 302  * to make sure this function only returns 1 once for a given ordered extent.
 303  *
 304  * file_offset is updated to one byte past the range that is recorded as
 305  * complete.  This allows you to walk forward in the file.
 306  */
 307 int btrfs_dec_test_first_ordered_pending(struct inode *inode,
 308                                    struct btrfs_ordered_extent **cached,
 309                                    u64 *file_offset, u64 io_size, int uptodate)
 310 {
 311         struct btrfs_ordered_inode_tree *tree;
 312         struct rb_node *node;
 313         struct btrfs_ordered_extent *entry = NULL;
 314         int ret;
 315         unsigned long flags;
 316         u64 dec_end;
 317         u64 dec_start;
 318         u64 to_dec;
 319
 320         tree = &BTRFS_I(inode)->ordered_tree;
 321         spin_lock_irqsave(&tree->lock, flags);
 322         node = tree_search(tree, *file_offset);
 323         if (!node) {
 324                 ret = 1;
 325                 goto out;
 326         }
 327
 328         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 329         if (!offset_in_entry(entry, *file_offset)) {
 330                 ret = 1;
 331                 goto out;
 332         }
 333
 334         dec_start = max(*file_offset, entry->file_offset);
 335         dec_end = min(*file_offset + io_size, entry->file_offset +
 336                       entry->len);
 337         *file_offset = dec_end;
 338         if (dec_start > dec_end) {
 339                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
 340                         "bad ordering dec_start %llu end %llu", dec_start, dec_end);
 341         }
 342         to_dec = dec_end - dec_start;
 343         if (to_dec > entry->bytes_left) {
 344                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
 345                         "bad ordered accounting left %llu size %llu",
 346                         entry->bytes_left, to_dec);
 347         }
 348         entry->bytes_left -= to_dec;
 349         if (!uptodate)
 350                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 351
 352         if (entry->bytes_left == 0) {
 353                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 354                 if (waitqueue_active(&entry->wait))
 355                         wake_up(&entry->wait);
 356         } else {
 357                 ret = 1;
 358         }
 359 out:
 360         if (!ret && cached && entry) {
 361                 *cached = entry;
 362                 atomic_inc(&entry->refs);
 363         }
 364         spin_unlock_irqrestore(&tree->lock, flags);
 365         return ret == 0;
 366 }
 367
 368 /*
 369  * this is used to account for finished IO across a given range
 370  * of the file.  The IO should not span ordered extents.  If
 371  * a given ordered_extent is completely done, 1 is returned, otherwise
 372  * 0.
 373  *
 374  * test_and_set_bit on a flag in the struct btrfs_ordered_extent is used
 375  * to make sure this function only returns 1 once for a given ordered extent.
 376  */
 377 int btrfs_dec_test_ordered_pending(struct inode *inode,
 378                                    struct btrfs_ordered_extent **cached,
 379                                    u64 file_offset, u64 io_size, int uptodate)
 380 {
 381         struct btrfs_ordered_inode_tree *tree;
 382         struct rb_node *node;
 383         struct btrfs_ordered_extent *entry = NULL;
 384         unsigned long flags;
 385         int ret;
 386
 387         tree = &BTRFS_I(inode)->ordered_tree;
 388         spin_lock_irqsave(&tree->lock, flags);
 389         if (cached && *cached) {
 390                 entry = *cached;
 391                 goto have_entry;
 392         }
 393
 394         node = tree_search(tree, file_offset);
 395         if (!node) {
 396                 ret = 1;
 397                 goto out;
 398         }
 399
 400         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 401 have_entry:
 402         if (!offset_in_entry(entry, file_offset)) {
 403                 ret = 1;
 404                 goto out;
 405         }
 406
 407         if (io_size > entry->bytes_left) {
 408                 btrfs_crit(BTRFS_I(inode)->root->fs_info,
 409                            "bad ordered accounting left %llu size %llu",
 410                        entry->bytes_left, io_size);
 411         }
 412         entry->bytes_left -= io_size;
 413         if (!uptodate)
 414                 set_bit(BTRFS_ORDERED_IOERR, &entry->flags);
 415
 416         if (entry->bytes_left == 0) {
 417                 ret = test_and_set_bit(BTRFS_ORDERED_IO_DONE, &entry->flags);
 418                 if (waitqueue_active(&entry->wait))
 419                         wake_up(&entry->wait);
 420         } else {
 421                 ret = 1;
 422         }
 423 out:
 424         if (!ret && cached && entry) {
 425                 *cached = entry;
 426                 atomic_inc(&entry->refs);
 427         }
 428         spin_unlock_irqrestore(&tree->lock, flags);
 429         return ret == 0;
 430 }
 431
 432 /* Needs to either be called under a log transaction or the log_mutex */
 433 void btrfs_get_logged_extents(struct inode *inode,
 434                               struct list_head *logged_list)
 435 {
 436         struct btrfs_ordered_inode_tree *tree;
 437         struct btrfs_ordered_extent *ordered;
 438         struct rb_node *n;
 439
 440         tree = &BTRFS_I(inode)->ordered_tree;
 441         spin_lock_irq(&tree->lock);
 442         for (n = rb_first(&tree->tree); n; n = rb_next(n)) {
 443                 ordered = rb_entry(n, struct btrfs_ordered_extent, rb_node);
 444                 if (!list_empty(&ordered->log_list))
 445                         continue;
 446                 list_add_tail(&ordered->log_list, logged_list);
 447                 atomic_inc(&ordered->refs);
 448         }
 449         spin_unlock_irq(&tree->lock);
 450 }
 451
 452 void btrfs_put_logged_extents(struct list_head *logged_list)
 453 {
 454         struct btrfs_ordered_extent *ordered;
 455
 456         while (!list_empty(logged_list)) {
 457                 ordered = list_first_entry(logged_list,
 458                                            struct btrfs_ordered_extent,
 459                                            log_list);
 460                 list_del_init(&ordered->log_list);
 461                 btrfs_put_ordered_extent(ordered);
 462         }
 463 }
 464
 465 void btrfs_submit_logged_extents(struct list_head *logged_list,
 466                                  struct btrfs_root *log)
 467 {
 468         int index = log->log_transid % 2;
 469
 470         spin_lock_irq(&log->log_extents_lock[index]);
 471         list_splice_tail(logged_list, &log->logged_list[index]);
 472         spin_unlock_irq(&log->log_extents_lock[index]);
 473 }
 474
 475 void btrfs_wait_logged_extents(struct btrfs_root *log, u64 transid)
 476 {
 477         struct btrfs_ordered_extent *ordered;
 478         int index = transid % 2;
 479
 480         spin_lock_irq(&log->log_extents_lock[index]);
 481         while (!list_empty(&log->logged_list[index])) {
 482                 ordered = list_first_entry(&log->logged_list[index],
 483                                            struct btrfs_ordered_extent,
 484                                            log_list);
 485                 list_del_init(&ordered->log_list);
 486                 spin_unlock_irq(&log->log_extents_lock[index]);
 487
 488                 if (!test_bit(BTRFS_ORDERED_IO_DONE, &ordered->flags) &&
 489                     !test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags)) {
 490                         struct inode *inode = ordered->inode;
 491                         u64 start = ordered->file_offset;
 492                         u64 end = ordered->file_offset + ordered->len - 1;
 493
 494                         WARN_ON(!inode);
 495                         filemap_fdatawrite_range(inode->i_mapping, start, end);
 496                 }
 497                 wait_event(ordered->wait, test_bit(BTRFS_ORDERED_IO_DONE,
 498                                                    &ordered->flags));
 499
 500                 btrfs_put_ordered_extent(ordered);
 501                 spin_lock_irq(&log->log_extents_lock[index]);
 502         }
 503         spin_unlock_irq(&log->log_extents_lock[index]);
 504 }
 505
 506 void btrfs_free_logged_extents(struct btrfs_root *log, u64 transid)
 507 {
 508         struct btrfs_ordered_extent *ordered;
 509         int index = transid % 2;
 510
 511         spin_lock_irq(&log->log_extents_lock[index]);
 512         while (!list_empty(&log->logged_list[index])) {
 513                 ordered = list_first_entry(&log->logged_list[index],
 514                                            struct btrfs_ordered_extent,
 515                                            log_list);
 516                 list_del_init(&ordered->log_list);
 517                 spin_unlock_irq(&log->log_extents_lock[index]);
 518                 btrfs_put_ordered_extent(ordered);
 519                 spin_lock_irq(&log->log_extents_lock[index]);
 520         }
 521         spin_unlock_irq(&log->log_extents_lock[index]);
 522 }
 523
 524 /*
 525  * used to drop a reference on an ordered extent.  This will free
 526  * the extent if the last reference is dropped
 527  */
 528 void btrfs_put_ordered_extent(struct btrfs_ordered_extent *entry)
 529 {
 530         struct list_head *cur;
 531         struct btrfs_ordered_sum *sum;
 532
 533         trace_btrfs_ordered_extent_put(entry->inode, entry);
 534
 535         if (atomic_dec_and_test(&entry->refs)) {
 536                 if (entry->inode)
 537                         btrfs_add_delayed_iput(entry->inode);
 538                 while (!list_empty(&entry->list)) {
 539                         cur = entry->list.next;
 540                         sum = list_entry(cur, struct btrfs_ordered_sum, list);
 541                         list_del(&sum->list);
 542                         kfree(sum);
 543                 }
 544                 kmem_cache_free(btrfs_ordered_extent_cache, entry);
 545         }
 546 }
 547
 548 /*
 549  * remove an ordered extent from the tree.  No references are dropped
 550  * and waiters are woken up.
 551  */
 552 void btrfs_remove_ordered_extent(struct inode *inode,
 553                                  struct btrfs_ordered_extent *entry)
 554 {
 555         struct btrfs_ordered_inode_tree *tree;
 556         struct btrfs_root *root = BTRFS_I(inode)->root;
 557         struct rb_node *node;
 558
 559         tree = &BTRFS_I(inode)->ordered_tree;
 560         spin_lock_irq(&tree->lock);
 561         node = &entry->rb_node;
 562         rb_erase(node, &tree->tree);
 563         if (tree->last == node)
 564                 tree->last = NULL;
 565         set_bit(BTRFS_ORDERED_COMPLETE, &entry->flags);
 566         spin_unlock_irq(&tree->lock);
 567
 568         spin_lock(&root->ordered_extent_lock);
 569         list_del_init(&entry->root_extent_list);
 570         root->nr_ordered_extents--;
 571
 572         trace_btrfs_ordered_extent_remove(inode, entry);
 573
 574         /*
 575          * we have no more ordered extents for this inode and
 576          * no dirty pages.  We can safely remove it from the
 577          * list of ordered extents
 578          */
 579         if (RB_EMPTY_ROOT(&tree->tree) &&
 580             !mapping_tagged(inode->i_mapping, PAGECACHE_TAG_DIRTY)) {
 581                 spin_lock(&root->fs_info->ordered_root_lock);
 582                 list_del_init(&BTRFS_I(inode)->ordered_operations);
 583                 spin_unlock(&root->fs_info->ordered_root_lock);
 584         }
 585
 586         if (!root->nr_ordered_extents) {
 587                 spin_lock(&root->fs_info->ordered_root_lock);
 588                 BUG_ON(list_empty(&root->ordered_root));
 589                 list_del_init(&root->ordered_root);
 590                 spin_unlock(&root->fs_info->ordered_root_lock);
 591         }
 592         spin_unlock(&root->ordered_extent_lock);
 593         wake_up(&entry->wait);
 594 }
 595
 596 static void btrfs_run_ordered_extent_work(struct btrfs_work *work)
 597 {
 598         struct btrfs_ordered_extent *ordered;
 599
 600         ordered = container_of(work, struct btrfs_ordered_extent, flush_work);
 601         btrfs_start_ordered_extent(ordered->inode, ordered, 1);
 602         complete(&ordered->completion);
 603 }
 604
 605 /*
 606  * wait for all the ordered extents in a root.  This is done when balancing
 607  * space between drives.
 608  */
 609 int btrfs_wait_ordered_extents(struct btrfs_root *root, int nr)
 610 {
 611         struct list_head splice, works;
 612         struct btrfs_ordered_extent *ordered, *next;
 613         int count = 0;
 614
 615         INIT_LIST_HEAD(&splice);
 616         INIT_LIST_HEAD(&works);
 617
 618         mutex_lock(&root->ordered_extent_mutex);
 619         spin_lock(&root->ordered_extent_lock);
 620         list_splice_init(&root->ordered_extents, &splice);
 621         while (!list_empty(&splice) && nr) {
 622                 ordered = list_first_entry(&splice, struct btrfs_ordered_extent,
 623                                            root_extent_list);
 624                 list_move_tail(&ordered->root_extent_list,
 625                                &root->ordered_extents);
 626                 atomic_inc(&ordered->refs);
 627                 spin_unlock(&root->ordered_extent_lock);
 628
 629                 btrfs_init_work(&ordered->flush_work,
 630                                 btrfs_run_ordered_extent_work, NULL, NULL);
 631                 list_add_tail(&ordered->work_list, &works);
 632                 btrfs_queue_work(root->fs_info->flush_workers,
 633                                  &ordered->flush_work);
 634
 635                 cond_resched();
 636                 spin_lock(&root->ordered_extent_lock);
 637                 if (nr != -1)
 638                         nr--;
 639                 count++;
 640         }
 641         list_splice_tail(&splice, &root->ordered_extents);
 642         spin_unlock(&root->ordered_extent_lock);
 643
 644         list_for_each_entry_safe(ordered, next, &works, work_list) {
 645                 list_del_init(&ordered->work_list);
 646                 wait_for_completion(&ordered->completion);
 647                 btrfs_put_ordered_extent(ordered);
 648                 cond_resched();
 649         }
 650         mutex_unlock(&root->ordered_extent_mutex);
 651
 652         return count;
 653 }
 654
 655 void btrfs_wait_ordered_roots(struct btrfs_fs_info *fs_info, int nr)
 656 {
 657         struct btrfs_root *root;
 658         struct list_head splice;
 659         int done;
 660
 661         INIT_LIST_HEAD(&splice);
 662
 663         mutex_lock(&fs_info->ordered_operations_mutex);
 664         spin_lock(&fs_info->ordered_root_lock);
 665         list_splice_init(&fs_info->ordered_roots, &splice);
 666         while (!list_empty(&splice) && nr) {
 667                 root = list_first_entry(&splice, struct btrfs_root,
 668                                         ordered_root);
 669                 root = btrfs_grab_fs_root(root);
 670                 BUG_ON(!root);
 671                 list_move_tail(&root->ordered_root,
 672                                &fs_info->ordered_roots);
 673                 spin_unlock(&fs_info->ordered_root_lock);
 674
 675                 done = btrfs_wait_ordered_extents(root, nr);
 676                 btrfs_put_fs_root(root);
 677
 678                 spin_lock(&fs_info->ordered_root_lock);
 679                 if (nr != -1) {
 680                         nr -= done;
 681                         WARN_ON(nr < 0);
 682                 }
 683         }
 684         list_splice_tail(&splice, &fs_info->ordered_roots);
 685         spin_unlock(&fs_info->ordered_root_lock);
 686         mutex_unlock(&fs_info->ordered_operations_mutex);
 687 }
 688
 689 /*
 690  * this is used during transaction commit to write all the inodes
 691  * added to the ordered operation list.  These files must be fully on
 692  * disk before the transaction commits.
 693  *
 694  * we have two modes here, one is to just start the IO via filemap_flush
 695  * and the other is to wait for all the io.  When we wait, we have an
 696  * extra check to make sure the ordered operation list really is empty
 697  * before we return
 698  */
 699 int btrfs_run_ordered_operations(struct btrfs_trans_handle *trans,
 700                                  struct btrfs_root *root, int wait)
 701 {
 702         struct btrfs_inode *btrfs_inode;
 703         struct inode *inode;
 704         struct btrfs_transaction *cur_trans = trans->transaction;
 705         struct list_head splice;
 706         struct list_head works;
 707         struct btrfs_delalloc_work *work, *next;
 708         int ret = 0;
 709
 710         INIT_LIST_HEAD(&splice);
 711         INIT_LIST_HEAD(&works);
 712
 713         mutex_lock(&root->fs_info->ordered_extent_flush_mutex);
 714         spin_lock(&root->fs_info->ordered_root_lock);
 715         list_splice_init(&cur_trans->ordered_operations, &splice);
 716         while (!list_empty(&splice)) {
 717                 btrfs_inode = list_entry(splice.next, struct btrfs_inode,
 718                                    ordered_operations);
 719                 inode = &btrfs_inode->vfs_inode;
 720
 721                 list_del_init(&btrfs_inode->ordered_operations);
 722
 723                 /*
 724                  * the inode may be getting freed (in sys_unlink path).
 725                  */
 726                 inode = igrab(inode);
 727                 if (!inode)
 728                         continue;
 729
 730                 if (!wait)
 731                         list_add_tail(&BTRFS_I(inode)->ordered_operations,
 732                                       &cur_trans->ordered_operations);
 733                 spin_unlock(&root->fs_info->ordered_root_lock);
 734
 735                 work = btrfs_alloc_delalloc_work(inode, wait, 1);
 736                 if (!work) {
 737                         spin_lock(&root->fs_info->ordered_root_lock);
 738                         if (list_empty(&BTRFS_I(inode)->ordered_operations))
 739                                 list_add_tail(&btrfs_inode->ordered_operations,
 740                                               &splice);
 741                         list_splice_tail(&splice,
 742                                          &cur_trans->ordered_operations);
 743                         spin_unlock(&root->fs_info->ordered_root_lock);
 744                         ret = -ENOMEM;
 745                         goto out;
 746                 }
 747                 list_add_tail(&work->list, &works);
 748                 btrfs_queue_work(root->fs_info->flush_workers,
 749                                  &work->work);
 750
 751                 cond_resched();
 752                 spin_lock(&root->fs_info->ordered_root_lock);
 753         }
 754         spin_unlock(&root->fs_info->ordered_root_lock);
 755 out:
 756         list_for_each_entry_safe(work, next, &works, list) {
 757                 list_del_init(&work->list);
 758                 btrfs_wait_and_free_delalloc_work(work);
 759         }
 760         mutex_unlock(&root->fs_info->ordered_extent_flush_mutex);
 761         return ret;
 762 }
 763
 764 /*
 765  * Used to start IO or wait for a given ordered extent to finish.
 766  *
 767  * If wait is one, this effectively waits on page writeback for all the pages
 768  * in the extent, and it waits on the io completion code to insert
 769  * metadata into the btree corresponding to the extent
 770  */
 771 void btrfs_start_ordered_extent(struct inode *inode,
 772                                        struct btrfs_ordered_extent *entry,
 773                                        int wait)
 774 {
 775         u64 start = entry->file_offset;
 776         u64 end = start + entry->len - 1;
 777
 778         trace_btrfs_ordered_extent_start(inode, entry);
 779
 780         /*
 781          * pages in the range can be dirty, clean or writeback.  We
 782          * start IO on any dirty ones so the wait doesn't stall waiting
 783          * for the flusher thread to find them
 784          */
 785         if (!test_bit(BTRFS_ORDERED_DIRECT, &entry->flags))
 786                 filemap_fdatawrite_range(inode->i_mapping, start, end);
 787         if (wait) {
 788                 wait_event(entry->wait, test_bit(BTRFS_ORDERED_COMPLETE,
 789                                                  &entry->flags));
 790         }
 791 }
 792
 793 /*
 794  * Used to wait on ordered extents across a large range of bytes.
 795  */
 796 int btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len)
 797 {
 798         int ret = 0;
 799         u64 end;
 800         u64 orig_end;
 801         struct btrfs_ordered_extent *ordered;
 802
 803         if (start + len < start) {
 804                 orig_end = INT_LIMIT(loff_t);
 805         } else {
 806                 orig_end = start + len - 1;
 807                 if (orig_end > INT_LIMIT(loff_t))
 808                         orig_end = INT_LIMIT(loff_t);
 809         }
 810
 811         /* start IO across the range first to instantiate any delalloc
 812          * extents
 813          */
 814         ret = filemap_fdatawrite_range(inode->i_mapping, start, orig_end);
 815         if (ret)
 816                 return ret;
 817         /*
 818          * So with compression we will find and lock a dirty page and clear the
 819          * first one as dirty, setup an async extent, and immediately return
 820          * with the entire range locked but with nobody actually marked with
 821          * writeback.  So we can't just filemap_write_and_wait_range() and
 822          * expect it to work since it will just kick off a thread to do the
 823          * actual work.  So we need to call filemap_fdatawrite_range _again_
 824          * since it will wait on the page lock, which won't be unlocked until
 825          * after the pages have been marked as writeback and so we're good to go
 826          * from there.  We have to do this otherwise we'll miss the ordered
 827          * extents and that results in badness.  Please Josef, do not think you
 828          * know better and pull this out at some point in the future, it is
 829          * right and you are wrong.
 830          */
 831         if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
 832                      &BTRFS_I(inode)->runtime_flags)) {
 833                 ret = filemap_fdatawrite_range(inode->i_mapping, start,
 834                                                orig_end);
 835                 if (ret)
 836                         return ret;
 837         }
 838         ret = filemap_fdatawait_range(inode->i_mapping, start, orig_end);
 839         if (ret)
 840                 return ret;
 841
 842         end = orig_end;
 843         while (1) {
 844                 ordered = btrfs_lookup_first_ordered_extent(inode, end);
 845                 if (!ordered)
 846                         break;
 847                 if (ordered->file_offset > orig_end) {
 848                         btrfs_put_ordered_extent(ordered);
 849                         break;
 850                 }
 851                 if (ordered->file_offset + ordered->len <= start) {
 852                         btrfs_put_ordered_extent(ordered);
 853                         break;
 854                 }
 855                 btrfs_start_ordered_extent(inode, ordered, 1);
 856                 end = ordered->file_offset;
 857                 if (test_bit(BTRFS_ORDERED_IOERR, &ordered->flags))
 858                         ret = -EIO;
 859                 btrfs_put_ordered_extent(ordered);
 860                 if (ret || end == 0 || end == start)
 861                         break;
 862                 end--;
 863         }
 864         return ret;
 865 }
 866
 867 /*
 868  * find an ordered extent corresponding to file_offset.  return NULL if
 869  * nothing is found, otherwise take a reference on the extent and return it
 870  */
 871 struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode,
 872                                                          u64 file_offset)
 873 {
 874         struct btrfs_ordered_inode_tree *tree;
 875         struct rb_node *node;
 876         struct btrfs_ordered_extent *entry = NULL;
 877
 878         tree = &BTRFS_I(inode)->ordered_tree;
 879         spin_lock_irq(&tree->lock);
 880         node = tree_search(tree, file_offset);
 881         if (!node)
 882                 goto out;
 883
 884         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 885         if (!offset_in_entry(entry, file_offset))
 886                 entry = NULL;
 887         if (entry)
 888                 atomic_inc(&entry->refs);
 889 out:
 890         spin_unlock_irq(&tree->lock);
 891         return entry;
 892 }
 893
 894 /* Since the DIO code tries to lock a wide area we need to look for any ordered
 895  * extents that exist in the range, rather than just the start of the range.
 896  */
 897 struct btrfs_ordered_extent *btrfs_lookup_ordered_range(struct inode *inode,
 898                                                         u64 file_offset,
 899                                                         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 = &BTRFS_I(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                 atomic_inc(&entry->refs);
 931         spin_unlock_irq(&tree->lock);
 932         return entry;
 933 }
 934
 935 /*
 936  * lookup and return any extent before 'file_offset'.  NULL is returned
 937  * if none is found
 938  */
 939 struct btrfs_ordered_extent *
 940 btrfs_lookup_first_ordered_extent(struct inode *inode, u64 file_offset)
 941 {
 942         struct btrfs_ordered_inode_tree *tree;
 943         struct rb_node *node;
 944         struct btrfs_ordered_extent *entry = NULL;
 945
 946         tree = &BTRFS_I(inode)->ordered_tree;
 947         spin_lock_irq(&tree->lock);
 948         node = tree_search(tree, file_offset);
 949         if (!node)
 950                 goto out;
 951
 952         entry = rb_entry(node, struct btrfs_ordered_extent, rb_node);
 953         atomic_inc(&entry->refs);
 954 out:
 955         spin_unlock_irq(&tree->lock);
 956         return entry;
 957 }
 958
 959 /*
 960  * After an extent is done, call this to conditionally update the on disk
 961  * i_size.  i_size is updated to cover any fully written part of the file.
 962  */
 963 int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
 964                                 struct btrfs_ordered_extent *ordered)
 965 {
 966         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
 967         u64 disk_i_size;
 968         u64 new_i_size;
 969         u64 i_size = i_size_read(inode);
 970         struct rb_node *node;
 971         struct rb_node *prev = NULL;
 972         struct btrfs_ordered_extent *test;
 973         int ret = 1;
 974
 975         spin_lock_irq(&tree->lock);
 976         if (ordered) {
 977                 offset = entry_end(ordered);
 978                 if (test_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags))
 979                         offset = min(offset,
 980                                      ordered->file_offset +
 981                                      ordered->truncated_len);
 982         } else {
 983                 offset = ALIGN(offset, BTRFS_I(inode)->root->sectorsize);
 984         }
 985         disk_i_size = BTRFS_I(inode)->disk_i_size;
 986
 987         /* truncate file */
 988         if (disk_i_size > i_size) {
 989                 BTRFS_I(inode)->disk_i_size = i_size;
 990                 ret = 0;
 991                 goto out;
 992         }
 993
 994         /*
 995          * if the disk i_size is already at the inode->i_size, or
 996          * this ordered extent is inside the disk i_size, we're done
 997          */
 998         if (disk_i_size == i_size)
 999                 goto out;
1000
1001         /*
1002          * We still need to update disk_i_size if outstanding_isize is greater
1003          * than disk_i_size.
1004          */
1005         if (offset <= disk_i_size &&
1006             (!ordered || ordered->outstanding_isize <= disk_i_size))
1007                 goto out;
1008
1009         /*
1010          * walk backward from this ordered extent to disk_i_size.
1011          * if we find an ordered extent then we can't update disk i_size
1012          * yet
1013          */
1014         if (ordered) {
1015                 node = rb_prev(&ordered->rb_node);
1016         } else {
1017                 prev = tree_search(tree, offset);
1018                 /*
1019                  * we insert file extents without involving ordered struct,
1020                  * so there should be no ordered struct cover this offset
1021                  */
1022                 if (prev) {
1023                         test = rb_entry(prev, struct btrfs_ordered_extent,
1024                                         rb_node);
1025                         BUG_ON(offset_in_entry(test, offset));
1026                 }
1027                 node = prev;
1028         }
1029         for (; node; node = rb_prev(node)) {
1030                 test = rb_entry(node, struct btrfs_ordered_extent, rb_node);
1031
1032                 /* We treat this entry as if it doesnt exist */
1033                 if (test_bit(BTRFS_ORDERED_UPDATED_ISIZE, &test->flags))
1034                         continue;
1035                 if (test->file_offset + test->len <= disk_i_size)
1036                         break;
1037                 if (test->file_offset >= i_size)
1038                         break;
1039                 if (entry_end(test) > disk_i_size) {
1040                         /*
1041                          * we don't update disk_i_size now, so record this
1042                          * undealt i_size. Or we will not know the real
1043                          * i_size.
1044                          */
1045                         if (test->outstanding_isize < offset)
1046                                 test->outstanding_isize = offset;
1047                         if (ordered &&
1048                             ordered->outstanding_isize >
1049                             test->outstanding_isize)
1050                                 test->outstanding_isize =
1051                                                 ordered->outstanding_isize;
1052                         goto out;
1053                 }
1054         }
1055         new_i_size = min_t(u64, offset, i_size);
1056
1057         /*
1058          * Some ordered extents may completed before the current one, and
1059          * we hold the real i_size in ->outstanding_isize.
1060          */
1061         if (ordered && ordered->outstanding_isize > new_i_size)
1062                 new_i_size = min_t(u64, ordered->outstanding_isize, i_size);
1063         BTRFS_I(inode)->disk_i_size = new_i_size;
1064         ret = 0;
1065 out:
1066         /*
1067          * We need to do this because we can't remove ordered extents until
1068          * after the i_disk_size has been updated and then the inode has been
1069          * updated to reflect the change, so we need to tell anybody who finds
1070          * this ordered extent that we've already done all the real work, we
1071          * just haven't completed all the other work.
1072          */
1073         if (ordered)
1074                 set_bit(BTRFS_ORDERED_UPDATED_ISIZE, &ordered->flags);
1075         spin_unlock_irq(&tree->lock);
1076         return ret;
1077 }
1078
1079 /*
1080  * search the ordered extents for one corresponding to 'offset' and
1081  * try to find a checksum.  This is used because we allow pages to
1082  * be reclaimed before their checksum is actually put into the btree
1083  */
1084 int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u64 disk_bytenr,
1085                            u32 *sum, int len)
1086 {
1087         struct btrfs_ordered_sum *ordered_sum;
1088         struct btrfs_ordered_extent *ordered;
1089         struct btrfs_ordered_inode_tree *tree = &BTRFS_I(inode)->ordered_tree;
1090         unsigned long num_sectors;
1091         unsigned long i;
1092         u32 sectorsize = BTRFS_I(inode)->root->sectorsize;
1093         int index = 0;
1094
1095         ordered = btrfs_lookup_ordered_extent(inode, offset);
1096         if (!ordered)
1097                 return 0;
1098
1099         spin_lock_irq(&tree->lock);
1100         list_for_each_entry_reverse(ordered_sum, &ordered->list, list) {
1101                 if (disk_bytenr >= ordered_sum->bytenr &&
1102                     disk_bytenr < ordered_sum->bytenr + ordered_sum->len) {
1103                         i = (disk_bytenr - ordered_sum->bytenr) >>
1104                             inode->i_sb->s_blocksize_bits;
1105                         num_sectors = ordered_sum->len >>
1106                                       inode->i_sb->s_blocksize_bits;
1107                         num_sectors = min_t(int, len - index, num_sectors - i);
1108                         memcpy(sum + index, ordered_sum->sums + i,
1109                                num_sectors);
1110
1111                         index += (int)num_sectors;
1112                         if (index == len)
1113                                 goto out;
1114                         disk_bytenr += num_sectors * sectorsize;
1115                 }
1116         }
1117 out:
1118         spin_unlock_irq(&tree->lock);
1119         btrfs_put_ordered_extent(ordered);
1120         return index;
1121 }
1122
1123
1124 /*
1125  * add a given inode to the list of inodes that must be fully on
1126  * disk before a transaction commit finishes.
1127  *
1128  * This basically gives us the ext3 style data=ordered mode, and it is mostly
1129  * used to make sure renamed files are fully on disk.
1130  *
1131  * It is a noop if the inode is already fully on disk.
1132  *
1133  * If trans is not null, we'll do a friendly check for a transaction that
1134  * is already flushing things and force the IO down ourselves.
1135  */
1136 void btrfs_add_ordered_operation(struct btrfs_trans_handle *trans,
1137                                  struct btrfs_root *root, struct inode *inode)
1138 {
1139         struct btrfs_transaction *cur_trans = trans->transaction;
1140         u64 last_mod;
1141
1142         last_mod = max(BTRFS_I(inode)->generation, BTRFS_I(inode)->last_trans);
1143
1144         /*
1145          * if this file hasn't been changed since the last transaction
1146          * commit, we can safely return without doing anything
1147          */
1148         if (last_mod <= root->fs_info->last_trans_committed)
1149                 return;
1150
1151         spin_lock(&root->fs_info->ordered_root_lock);
1152         if (list_empty(&BTRFS_I(inode)->ordered_operations)) {
1153                 list_add_tail(&BTRFS_I(inode)->ordered_operations,
1154                               &cur_trans->ordered_operations);
1155         }
1156         spin_unlock(&root->fs_info->ordered_root_lock);
1157 }
1158
1159 int __init ordered_data_init(void)
1160 {
1161         btrfs_ordered_extent_cache = kmem_cache_create("btrfs_ordered_extent",
1162                                      sizeof(struct btrfs_ordered_extent), 0,
1163                                      SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
1164                                      NULL);
1165         if (!btrfs_ordered_extent_cache)
1166                 return -ENOMEM;
1167
1168         return 0;
1169 }
1170
1171 void ordered_data_exit(void)
1172 {
1173         if (btrfs_ordered_extent_cache)
1174                 kmem_cache_destroy(btrfs_ordered_extent_cache);
1175 }