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