fs/btrfs/disk-io.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/fs.h>
  20 #include <linux/blkdev.h>
  21 #include <linux/scatterlist.h>
  22 #include <linux/swap.h>
  23 #include <linux/radix-tree.h>
  24 #include <linux/writeback.h>
  25 #include <linux/buffer_head.h>
  26 #include <linux/workqueue.h>
  27 #include <linux/kthread.h>
  28 #include <linux/freezer.h>
  29 #include <linux/crc32c.h>
  30 #include <linux/slab.h>
  31 #include <linux/migrate.h>
  32 #include "compat.h"
  33 #include "ctree.h"
  34 #include "disk-io.h"
  35 #include "transaction.h"
  36 #include "btrfs_inode.h"
  37 #include "volumes.h"
  38 #include "print-tree.h"
  39 #include "async-thread.h"
  40 #include "locking.h"
  41 #include "tree-log.h"
  42 #include "free-space-cache.h"
  43
  44 static struct extent_io_ops btree_extent_io_ops;
  45 static void end_workqueue_fn(struct btrfs_work *work);
  46 static void free_fs_root(struct btrfs_root *root);
  47 static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
  48                                     int read_only);
  49 static int btrfs_destroy_ordered_operations(struct btrfs_root *root);
  50 static int btrfs_destroy_ordered_extents(struct btrfs_root *root);
  51 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
  52                                       struct btrfs_root *root);
  53 static int btrfs_destroy_pending_snapshots(struct btrfs_transaction *t);
  54 static int btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
  55 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
  56                                         struct extent_io_tree *dirty_pages,
  57                                         int mark);
  58 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
  59                                        struct extent_io_tree *pinned_extents);
  60 static int btrfs_cleanup_transaction(struct btrfs_root *root);
  61
  62 /*
  63  * end_io_wq structs are used to do processing in task context when an IO is
  64  * complete.  This is used during reads to verify checksums, and it is used
  65  * by writes to insert metadata for new file extents after IO is complete.
  66  */
  67 struct end_io_wq {
  68         struct bio *bio;
  69         bio_end_io_t *end_io;
  70         void *private;
  71         struct btrfs_fs_info *info;
  72         int error;
  73         int metadata;
  74         struct list_head list;
  75         struct btrfs_work work;
  76 };
  77
  78 /*
  79  * async submit bios are used to offload expensive checksumming
  80  * onto the worker threads.  They checksum file and metadata bios
  81  * just before they are sent down the IO stack.
  82  */
  83 struct async_submit_bio {
  84         struct inode *inode;
  85         struct bio *bio;
  86         struct list_head list;
  87         extent_submit_bio_hook_t *submit_bio_start;
  88         extent_submit_bio_hook_t *submit_bio_done;
  89         int rw;
  90         int mirror_num;
  91         unsigned long bio_flags;
  92         /*
  93          * bio_offset is optional, can be used if the pages in the bio
  94          * can't tell us where in the file the bio should go
  95          */
  96         u64 bio_offset;
  97         struct btrfs_work work;
  98 };
  99
 100 /* These are used to set the lockdep class on the extent buffer locks.
 101  * The class is set by the readpage_end_io_hook after the buffer has
 102  * passed csum validation but before the pages are unlocked.
 103  *
 104  * The lockdep class is also set by btrfs_init_new_buffer on freshly
 105  * allocated blocks.
 106  *
 107  * The class is based on the level in the tree block, which allows lockdep
 108  * to know that lower nodes nest inside the locks of higher nodes.
 109  *
 110  * We also add a check to make sure the highest level of the tree is
 111  * the same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this
 112  * code needs update as well.
 113  */
 114 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 115 # if BTRFS_MAX_LEVEL != 8
 116 #  error
 117 # endif
 118 static struct lock_class_key btrfs_eb_class[BTRFS_MAX_LEVEL + 1];
 119 static const char *btrfs_eb_name[BTRFS_MAX_LEVEL + 1] = {
 120         /* leaf */
 121         "btrfs-extent-00",
 122         "btrfs-extent-01",
 123         "btrfs-extent-02",
 124         "btrfs-extent-03",
 125         "btrfs-extent-04",
 126         "btrfs-extent-05",
 127         "btrfs-extent-06",
 128         "btrfs-extent-07",
 129         /* highest possible level */
 130         "btrfs-extent-08",
 131 };
 132 #endif
 133
 134 /*
 135  * extents on the btree inode are pretty simple, there's one extent
 136  * that covers the entire device
 137  */
 138 static struct extent_map *btree_get_extent(struct inode *inode,
 139                 struct page *page, size_t page_offset, u64 start, u64 len,
 140                 int create)
 141 {
 142         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 143         struct extent_map *em;
 144         int ret;
 145
 146         read_lock(&em_tree->lock);
 147         em = lookup_extent_mapping(em_tree, start, len);
 148         if (em) {
 149                 em->bdev =
 150                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 151                 read_unlock(&em_tree->lock);
 152                 goto out;
 153         }
 154         read_unlock(&em_tree->lock);
 155
 156         em = alloc_extent_map(GFP_NOFS);
 157         if (!em) {
 158                 em = ERR_PTR(-ENOMEM);
 159                 goto out;
 160         }
 161         em->start = 0;
 162         em->len = (u64)-1;
 163         em->block_len = (u64)-1;
 164         em->block_start = 0;
 165         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 166
 167         write_lock(&em_tree->lock);
 168         ret = add_extent_mapping(em_tree, em);
 169         if (ret == -EEXIST) {
 170                 u64 failed_start = em->start;
 171                 u64 failed_len = em->len;
 172
 173                 free_extent_map(em);
 174                 em = lookup_extent_mapping(em_tree, start, len);
 175                 if (em) {
 176                         ret = 0;
 177                 } else {
 178                         em = lookup_extent_mapping(em_tree, failed_start,
 179                                                    failed_len);
 180                         ret = -EIO;
 181                 }
 182         } else if (ret) {
 183                 free_extent_map(em);
 184                 em = NULL;
 185         }
 186         write_unlock(&em_tree->lock);
 187
 188         if (ret)
 189                 em = ERR_PTR(ret);
 190 out:
 191         return em;
 192 }
 193
 194 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
 195 {
 196         return crc32c(seed, data, len);
 197 }
 198
 199 void btrfs_csum_final(u32 crc, char *result)
 200 {
 201         *(__le32 *)result = ~cpu_to_le32(crc);
 202 }
 203
 204 /*
 205  * compute the csum for a btree block, and either verify it or write it
 206  * into the csum field of the block.
 207  */
 208 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 209                            int verify)
 210 {
 211         u16 csum_size =
 212                 btrfs_super_csum_size(&root->fs_info->super_copy);
 213         char *result = NULL;
 214         unsigned long len;
 215         unsigned long cur_len;
 216         unsigned long offset = BTRFS_CSUM_SIZE;
 217         char *map_token = NULL;
 218         char *kaddr;
 219         unsigned long map_start;
 220         unsigned long map_len;
 221         int err;
 222         u32 crc = ~(u32)0;
 223         unsigned long inline_result;
 224
 225         len = buf->len - offset;
 226         while (len > 0) {
 227                 err = map_private_extent_buffer(buf, offset, 32,
 228                                         &map_token, &kaddr,
 229                                         &map_start, &map_len, KM_USER0);
 230                 if (err)
 231                         return 1;
 232                 cur_len = min(len, map_len - (offset - map_start));
 233                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
 234                                       crc, cur_len);
 235                 len -= cur_len;
 236                 offset += cur_len;
 237                 unmap_extent_buffer(buf, map_token, KM_USER0);
 238         }
 239         if (csum_size > sizeof(inline_result)) {
 240                 result = kzalloc(csum_size * sizeof(char), GFP_NOFS);
 241                 if (!result)
 242                         return 1;
 243         } else {
 244                 result = (char *)&inline_result;
 245         }
 246
 247         btrfs_csum_final(crc, result);
 248
 249         if (verify) {
 250                 if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
 251                         u32 val;
 252                         u32 found = 0;
 253                         memcpy(&found, result, csum_size);
 254
 255                         read_extent_buffer(buf, &val, 0, csum_size);
 256                         if (printk_ratelimit()) {
 257                                 printk(KERN_INFO "btrfs: %s checksum verify "
 258                                        "failed on %llu wanted %X found %X "
 259                                        "level %d\n",
 260                                        root->fs_info->sb->s_id,
 261                                        (unsigned long long)buf->start, val, found,
 262                                        btrfs_header_level(buf));
 263                         }
 264                         if (result != (char *)&inline_result)
 265                                 kfree(result);
 266                         return 1;
 267                 }
 268         } else {
 269                 write_extent_buffer(buf, result, 0, csum_size);
 270         }
 271         if (result != (char *)&inline_result)
 272                 kfree(result);
 273         return 0;
 274 }
 275
 276 /*
 277  * we can't consider a given block up to date unless the transid of the
 278  * block matches the transid in the parent node's pointer.  This is how we
 279  * detect blocks that either didn't get written at all or got written
 280  * in the wrong place.
 281  */
 282 static int verify_parent_transid(struct extent_io_tree *io_tree,
 283                                  struct extent_buffer *eb, u64 parent_transid)
 284 {
 285         struct extent_state *cached_state = NULL;
 286         int ret;
 287
 288         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
 289                 return 0;
 290
 291         lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
 292                          0, &cached_state, GFP_NOFS);
 293         if (extent_buffer_uptodate(io_tree, eb, cached_state) &&
 294             btrfs_header_generation(eb) == parent_transid) {
 295                 ret = 0;
 296                 goto out;
 297         }
 298         if (printk_ratelimit()) {
 299                 printk("parent transid verify failed on %llu wanted %llu "
 300                        "found %llu\n",
 301                        (unsigned long long)eb->start,
 302                        (unsigned long long)parent_transid,
 303                        (unsigned long long)btrfs_header_generation(eb));
 304         }
 305         ret = 1;
 306         clear_extent_buffer_uptodate(io_tree, eb, &cached_state);
 307 out:
 308         unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
 309                              &cached_state, GFP_NOFS);
 310         return ret;
 311 }
 312
 313 /*
 314  * helper to read a given tree block, doing retries as required when
 315  * the checksums don't match and we have alternate mirrors to try.
 316  */
 317 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
 318                                           struct extent_buffer *eb,
 319                                           u64 start, u64 parent_transid)
 320 {
 321         struct extent_io_tree *io_tree;
 322         int ret;
 323         int num_copies = 0;
 324         int mirror_num = 0;
 325
 326         clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
 327         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
 328         while (1) {
 329                 ret = read_extent_buffer_pages(io_tree, eb, start, 1,
 330                                                btree_get_extent, mirror_num);
 331                 if (!ret &&
 332                     !verify_parent_transid(io_tree, eb, parent_transid))
 333                         return ret;
 334
 335                 /*
 336                  * This buffer's crc is fine, but its contents are corrupted, so
 337                  * there is no reason to read the other copies, they won't be
 338                  * any less wrong.
 339                  */
 340                 if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags))
 341                         return ret;
 342
 343                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
 344                                               eb->start, eb->len);
 345                 if (num_copies == 1)
 346                         return ret;
 347
 348                 mirror_num++;
 349                 if (mirror_num > num_copies)
 350                         return ret;
 351         }
 352         return -EIO;
 353 }
 354
 355 /*
 356  * checksum a dirty tree block before IO.  This has extra checks to make sure
 357  * we only fill in the checksum field in the first page of a multi-page block
 358  */
 359
 360 static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 361 {
 362         struct extent_io_tree *tree;
 363         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
 364         u64 found_start;
 365         unsigned long len;
 366         struct extent_buffer *eb;
 367         int ret;
 368
 369         tree = &BTRFS_I(page->mapping->host)->io_tree;
 370
 371         if (page->private == EXTENT_PAGE_PRIVATE) {
 372                 WARN_ON(1);
 373                 goto out;
 374         }
 375         if (!page->private) {
 376                 WARN_ON(1);
 377                 goto out;
 378         }
 379         len = page->private >> 2;
 380         WARN_ON(len == 0);
 381
 382         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 383         if (eb == NULL) {
 384                 WARN_ON(1);
 385                 goto out;
 386         }
 387         ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
 388                                              btrfs_header_generation(eb));
 389         BUG_ON(ret);
 390         WARN_ON(!btrfs_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN));
 391
 392         found_start = btrfs_header_bytenr(eb);
 393         if (found_start != start) {
 394                 WARN_ON(1);
 395                 goto err;
 396         }
 397         if (eb->first_page != page) {
 398                 WARN_ON(1);
 399                 goto err;
 400         }
 401         if (!PageUptodate(page)) {
 402                 WARN_ON(1);
 403                 goto err;
 404         }
 405         csum_tree_block(root, eb, 0);
 406 err:
 407         free_extent_buffer(eb);
 408 out:
 409         return 0;
 410 }
 411
 412 static int check_tree_block_fsid(struct btrfs_root *root,
 413                                  struct extent_buffer *eb)
 414 {
 415         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
 416         u8 fsid[BTRFS_UUID_SIZE];
 417         int ret = 1;
 418
 419         read_extent_buffer(eb, fsid, (unsigned long)btrfs_header_fsid(eb),
 420                            BTRFS_FSID_SIZE);
 421         while (fs_devices) {
 422                 if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
 423                         ret = 0;
 424                         break;
 425                 }
 426                 fs_devices = fs_devices->seed;
 427         }
 428         return ret;
 429 }
 430
 431 #define CORRUPT(reason, eb, root, slot)                         \
 432         printk(KERN_CRIT "btrfs: corrupt leaf, %s: block=%llu," \
 433                "root=%llu, slot=%d\n", reason,                  \
 434                (unsigned long long)btrfs_header_bytenr(eb),     \
 435                (unsigned long long)root->objectid, slot)
 436
 437 static noinline int check_leaf(struct btrfs_root *root,
 438                                struct extent_buffer *leaf)
 439 {
 440         struct btrfs_key key;
 441         struct btrfs_key leaf_key;
 442         u32 nritems = btrfs_header_nritems(leaf);
 443         int slot;
 444
 445         if (nritems == 0)
 446                 return 0;
 447
 448         /* Check the 0 item */
 449         if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
 450             BTRFS_LEAF_DATA_SIZE(root)) {
 451                 CORRUPT("invalid item offset size pair", leaf, root, 0);
 452                 return -EIO;
 453         }
 454
 455         /*
 456          * Check to make sure each items keys are in the correct order and their
 457          * offsets make sense.  We only have to loop through nritems-1 because
 458          * we check the current slot against the next slot, which verifies the
 459          * next slot's offset+size makes sense and that the current's slot
 460          * offset is correct.
 461          */
 462         for (slot = 0; slot < nritems - 1; slot++) {
 463                 btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
 464                 btrfs_item_key_to_cpu(leaf, &key, slot + 1);
 465
 466                 /* Make sure the keys are in the right order */
 467                 if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
 468                         CORRUPT("bad key order", leaf, root, slot);
 469                         return -EIO;
 470                 }
 471
 472                 /*
 473                  * Make sure the offset and ends are right, remember that the
 474                  * item data starts at the end of the leaf and grows towards the
 475                  * front.
 476                  */
 477                 if (btrfs_item_offset_nr(leaf, slot) !=
 478                         btrfs_item_end_nr(leaf, slot + 1)) {
 479                         CORRUPT("slot offset bad", leaf, root, slot);
 480                         return -EIO;
 481                 }
 482
 483                 /*
 484                  * Check to make sure that we don't point outside of the leaf,
 485                  * just incase all the items are consistent to eachother, but
 486                  * all point outside of the leaf.
 487                  */
 488                 if (btrfs_item_end_nr(leaf, slot) >
 489                     BTRFS_LEAF_DATA_SIZE(root)) {
 490                         CORRUPT("slot end outside of leaf", leaf, root, slot);
 491                         return -EIO;
 492                 }
 493         }
 494
 495         return 0;
 496 }
 497
 498 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 499 void btrfs_set_buffer_lockdep_class(struct extent_buffer *eb, int level)
 500 {
 501         lockdep_set_class_and_name(&eb->lock,
 502                            &btrfs_eb_class[level],
 503                            btrfs_eb_name[level]);
 504 }
 505 #endif
 506
 507 static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 508                                struct extent_state *state)
 509 {
 510         struct extent_io_tree *tree;
 511         u64 found_start;
 512         int found_level;
 513         unsigned long len;
 514         struct extent_buffer *eb;
 515         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 516         int ret = 0;
 517
 518         tree = &BTRFS_I(page->mapping->host)->io_tree;
 519         if (page->private == EXTENT_PAGE_PRIVATE)
 520                 goto out;
 521         if (!page->private)
 522                 goto out;
 523
 524         len = page->private >> 2;
 525         WARN_ON(len == 0);
 526
 527         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 528         if (eb == NULL) {
 529                 ret = -EIO;
 530                 goto out;
 531         }
 532
 533         found_start = btrfs_header_bytenr(eb);
 534         if (found_start != start) {
 535                 if (printk_ratelimit()) {
 536                         printk(KERN_INFO "btrfs bad tree block start "
 537                                "%llu %llu\n",
 538                                (unsigned long long)found_start,
 539                                (unsigned long long)eb->start);
 540                 }
 541                 ret = -EIO;
 542                 goto err;
 543         }
 544         if (eb->first_page != page) {
 545                 printk(KERN_INFO "btrfs bad first page %lu %lu\n",
 546                        eb->first_page->index, page->index);
 547                 WARN_ON(1);
 548                 ret = -EIO;
 549                 goto err;
 550         }
 551         if (check_tree_block_fsid(root, eb)) {
 552                 if (printk_ratelimit()) {
 553                         printk(KERN_INFO "btrfs bad fsid on block %llu\n",
 554                                (unsigned long long)eb->start);
 555                 }
 556                 ret = -EIO;
 557                 goto err;
 558         }
 559         found_level = btrfs_header_level(eb);
 560
 561         btrfs_set_buffer_lockdep_class(eb, found_level);
 562
 563         ret = csum_tree_block(root, eb, 1);
 564         if (ret) {
 565                 ret = -EIO;
 566                 goto err;
 567         }
 568
 569         /*
 570          * If this is a leaf block and it is corrupt, set the corrupt bit so
 571          * that we don't try and read the other copies of this block, just
 572          * return -EIO.
 573          */
 574         if (found_level == 0 && check_leaf(root, eb)) {
 575                 set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
 576                 ret = -EIO;
 577         }
 578
 579         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
 580         end = eb->start + end - 1;
 581 err:
 582         free_extent_buffer(eb);
 583 out:
 584         return ret;
 585 }
 586
 587 static void end_workqueue_bio(struct bio *bio, int err)
 588 {
 589         struct end_io_wq *end_io_wq = bio->bi_private;
 590         struct btrfs_fs_info *fs_info;
 591
 592         fs_info = end_io_wq->info;
 593         end_io_wq->error = err;
 594         end_io_wq->work.func = end_workqueue_fn;
 595         end_io_wq->work.flags = 0;
 596
 597         if (bio->bi_rw & REQ_WRITE) {
 598                 if (end_io_wq->metadata == 1)
 599                         btrfs_queue_worker(&fs_info->endio_meta_write_workers,
 600                                            &end_io_wq->work);
 601                 else if (end_io_wq->metadata == 2)
 602                         btrfs_queue_worker(&fs_info->endio_freespace_worker,
 603                                            &end_io_wq->work);
 604                 else
 605                         btrfs_queue_worker(&fs_info->endio_write_workers,
 606                                            &end_io_wq->work);
 607         } else {
 608                 if (end_io_wq->metadata)
 609                         btrfs_queue_worker(&fs_info->endio_meta_workers,
 610                                            &end_io_wq->work);
 611                 else
 612                         btrfs_queue_worker(&fs_info->endio_workers,
 613                                            &end_io_wq->work);
 614         }
 615 }
 616
 617 /*
 618  * For the metadata arg you want
 619  *
 620  * 0 - if data
 621  * 1 - if normal metadta
 622  * 2 - if writing to the free space cache area
 623  */
 624 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 625                         int metadata)
 626 {
 627         struct end_io_wq *end_io_wq;
 628         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
 629         if (!end_io_wq)
 630                 return -ENOMEM;
 631
 632         end_io_wq->private = bio->bi_private;
 633         end_io_wq->end_io = bio->bi_end_io;
 634         end_io_wq->info = info;
 635         end_io_wq->error = 0;
 636         end_io_wq->bio = bio;
 637         end_io_wq->metadata = metadata;
 638
 639         bio->bi_private = end_io_wq;
 640         bio->bi_end_io = end_workqueue_bio;
 641         return 0;
 642 }
 643
 644 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
 645 {
 646         unsigned long limit = min_t(unsigned long,
 647                                     info->workers.max_workers,
 648                                     info->fs_devices->open_devices);
 649         return 256 * limit;
 650 }
 651
 652 int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
 653 {
 654         return atomic_read(&info->nr_async_bios) >
 655                 btrfs_async_submit_limit(info);
 656 }
 657
 658 static void run_one_async_start(struct btrfs_work *work)
 659 {
 660         struct async_submit_bio *async;
 661
 662         async = container_of(work, struct  async_submit_bio, work);
 663         async->submit_bio_start(async->inode, async->rw, async->bio,
 664                                async->mirror_num, async->bio_flags,
 665                                async->bio_offset);
 666 }
 667
 668 static void run_one_async_done(struct btrfs_work *work)
 669 {
 670         struct btrfs_fs_info *fs_info;
 671         struct async_submit_bio *async;
 672         int limit;
 673
 674         async = container_of(work, struct  async_submit_bio, work);
 675         fs_info = BTRFS_I(async->inode)->root->fs_info;
 676
 677         limit = btrfs_async_submit_limit(fs_info);
 678         limit = limit * 2 / 3;
 679
 680         atomic_dec(&fs_info->nr_async_submits);
 681
 682         if (atomic_read(&fs_info->nr_async_submits) < limit &&
 683             waitqueue_active(&fs_info->async_submit_wait))
 684                 wake_up(&fs_info->async_submit_wait);
 685
 686         async->submit_bio_done(async->inode, async->rw, async->bio,
 687                                async->mirror_num, async->bio_flags,
 688                                async->bio_offset);
 689 }
 690
 691 static void run_one_async_free(struct btrfs_work *work)
 692 {
 693         struct async_submit_bio *async;
 694
 695         async = container_of(work, struct  async_submit_bio, work);
 696         kfree(async);
 697 }
 698
 699 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 700                         int rw, struct bio *bio, int mirror_num,
 701                         unsigned long bio_flags,
 702                         u64 bio_offset,
 703                         extent_submit_bio_hook_t *submit_bio_start,
 704                         extent_submit_bio_hook_t *submit_bio_done)
 705 {
 706         struct async_submit_bio *async;
 707
 708         async = kmalloc(sizeof(*async), GFP_NOFS);
 709         if (!async)
 710                 return -ENOMEM;
 711
 712         async->inode = inode;
 713         async->rw = rw;
 714         async->bio = bio;
 715         async->mirror_num = mirror_num;
 716         async->submit_bio_start = submit_bio_start;
 717         async->submit_bio_done = submit_bio_done;
 718
 719         async->work.func = run_one_async_start;
 720         async->work.ordered_func = run_one_async_done;
 721         async->work.ordered_free = run_one_async_free;
 722
 723         async->work.flags = 0;
 724         async->bio_flags = bio_flags;
 725         async->bio_offset = bio_offset;
 726
 727         atomic_inc(&fs_info->nr_async_submits);
 728
 729         if (rw & REQ_SYNC)
 730                 btrfs_set_work_high_prio(&async->work);
 731
 732         btrfs_queue_worker(&fs_info->workers, &async->work);
 733
 734         while (atomic_read(&fs_info->async_submit_draining) &&
 735               atomic_read(&fs_info->nr_async_submits)) {
 736                 wait_event(fs_info->async_submit_wait,
 737                            (atomic_read(&fs_info->nr_async_submits) == 0));
 738         }
 739
 740         return 0;
 741 }
 742
 743 static int btree_csum_one_bio(struct bio *bio)
 744 {
 745         struct bio_vec *bvec = bio->bi_io_vec;
 746         int bio_index = 0;
 747         struct btrfs_root *root;
 748
 749         WARN_ON(bio->bi_vcnt <= 0);
 750         while (bio_index < bio->bi_vcnt) {
 751                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
 752                 csum_dirty_buffer(root, bvec->bv_page);
 753                 bio_index++;
 754                 bvec++;
 755         }
 756         return 0;
 757 }
 758
 759 static int __btree_submit_bio_start(struct inode *inode, int rw,
 760                                     struct bio *bio, int mirror_num,
 761                                     unsigned long bio_flags,
 762                                     u64 bio_offset)
 763 {
 764         /*
 765          * when we're called for a write, we're already in the async
 766          * submission context.  Just jump into btrfs_map_bio
 767          */
 768         btree_csum_one_bio(bio);
 769         return 0;
 770 }
 771
 772 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
 773                                  int mirror_num, unsigned long bio_flags,
 774                                  u64 bio_offset)
 775 {
 776         /*
 777          * when we're called for a write, we're already in the async
 778          * submission context.  Just jump into btrfs_map_bio
 779          */
 780         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
 781 }
 782
 783 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 784                                  int mirror_num, unsigned long bio_flags,
 785                                  u64 bio_offset)
 786 {
 787         int ret;
 788
 789         ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
 790                                           bio, 1);
 791         BUG_ON(ret);
 792
 793         if (!(rw & REQ_WRITE)) {
 794                 /*
 795                  * called for a read, do the setup so that checksum validation
 796                  * can happen in the async kernel threads
 797                  */
 798                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 799                                      mirror_num, 0);
 800         }
 801
 802         /*
 803          * kthread helpers are used to submit writes so that checksumming
 804          * can happen in parallel across all CPUs
 805          */
 806         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
 807                                    inode, rw, bio, mirror_num, 0,
 808                                    bio_offset,
 809                                    __btree_submit_bio_start,
 810                                    __btree_submit_bio_done);
 811 }
 812
 813 #ifdef CONFIG_MIGRATION
 814 static int btree_migratepage(struct address_space *mapping,
 815                         struct page *newpage, struct page *page)
 816 {
 817         /*
 818          * we can't safely write a btree page from here,
 819          * we haven't done the locking hook
 820          */
 821         if (PageDirty(page))
 822                 return -EAGAIN;
 823         /*
 824          * Buffers may be managed in a filesystem specific way.
 825          * We must have no buffers or drop them.
 826          */
 827         if (page_has_private(page) &&
 828             !try_to_release_page(page, GFP_KERNEL))
 829                 return -EAGAIN;
 830         return migrate_page(mapping, newpage, page);
 831 }
 832 #endif
 833
 834 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 835 {
 836         struct extent_io_tree *tree;
 837         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 838         struct extent_buffer *eb;
 839         int was_dirty;
 840
 841         tree = &BTRFS_I(page->mapping->host)->io_tree;
 842         if (!(current->flags & PF_MEMALLOC)) {
 843                 return extent_write_full_page(tree, page,
 844                                               btree_get_extent, wbc);
 845         }
 846
 847         redirty_page_for_writepage(wbc, page);
 848         eb = btrfs_find_tree_block(root, page_offset(page), PAGE_CACHE_SIZE);
 849         WARN_ON(!eb);
 850
 851         was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
 852         if (!was_dirty) {
 853                 spin_lock(&root->fs_info->delalloc_lock);
 854                 root->fs_info->dirty_metadata_bytes += PAGE_CACHE_SIZE;
 855                 spin_unlock(&root->fs_info->delalloc_lock);
 856         }
 857         free_extent_buffer(eb);
 858
 859         unlock_page(page);
 860         return 0;
 861 }
 862
 863 static int btree_writepages(struct address_space *mapping,
 864                             struct writeback_control *wbc)
 865 {
 866         struct extent_io_tree *tree;
 867         tree = &BTRFS_I(mapping->host)->io_tree;
 868         if (wbc->sync_mode == WB_SYNC_NONE) {
 869                 struct btrfs_root *root = BTRFS_I(mapping->host)->root;
 870                 u64 num_dirty;
 871                 unsigned long thresh = 32 * 1024 * 1024;
 872
 873                 if (wbc->for_kupdate)
 874                         return 0;
 875
 876                 /* this is a bit racy, but that's ok */
 877                 num_dirty = root->fs_info->dirty_metadata_bytes;
 878                 if (num_dirty < thresh)
 879                         return 0;
 880         }
 881         return extent_writepages(tree, mapping, btree_get_extent, wbc);
 882 }
 883
 884 static int btree_readpage(struct file *file, struct page *page)
 885 {
 886         struct extent_io_tree *tree;
 887         tree = &BTRFS_I(page->mapping->host)->io_tree;
 888         return extent_read_full_page(tree, page, btree_get_extent);
 889 }
 890
 891 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 892 {
 893         struct extent_io_tree *tree;
 894         struct extent_map_tree *map;
 895         int ret;
 896
 897         if (PageWriteback(page) || PageDirty(page))
 898                 return 0;
 899
 900         tree = &BTRFS_I(page->mapping->host)->io_tree;
 901         map = &BTRFS_I(page->mapping->host)->extent_tree;
 902
 903         ret = try_release_extent_state(map, tree, page, gfp_flags);
 904         if (!ret)
 905                 return 0;
 906
 907         ret = try_release_extent_buffer(tree, page);
 908         if (ret == 1) {
 909                 ClearPagePrivate(page);
 910                 set_page_private(page, 0);
 911                 page_cache_release(page);
 912         }
 913
 914         return ret;
 915 }
 916
 917 static void btree_invalidatepage(struct page *page, unsigned long offset)
 918 {
 919         struct extent_io_tree *tree;
 920         tree = &BTRFS_I(page->mapping->host)->io_tree;
 921         extent_invalidatepage(tree, page, offset);
 922         btree_releasepage(page, GFP_NOFS);
 923         if (PagePrivate(page)) {
 924                 printk(KERN_WARNING "btrfs warning page private not zero "
 925                        "on page %llu\n", (unsigned long long)page_offset(page));
 926                 ClearPagePrivate(page);
 927                 set_page_private(page, 0);
 928                 page_cache_release(page);
 929         }
 930 }
 931
 932 static const struct address_space_operations btree_aops = {
 933         .readpage       = btree_readpage,
 934         .writepage      = btree_writepage,
 935         .writepages     = btree_writepages,
 936         .releasepage    = btree_releasepage,
 937         .invalidatepage = btree_invalidatepage,
 938         .sync_page      = block_sync_page,
 939 #ifdef CONFIG_MIGRATION
 940         .migratepage    = btree_migratepage,
 941 #endif
 942 };
 943
 944 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 945                          u64 parent_transid)
 946 {
 947         struct extent_buffer *buf = NULL;
 948         struct inode *btree_inode = root->fs_info->btree_inode;
 949         int ret = 0;
 950
 951         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 952         if (!buf)
 953                 return 0;
 954         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
 955                                  buf, 0, 0, btree_get_extent, 0);
 956         free_extent_buffer(buf);
 957         return ret;
 958 }
 959
 960 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
 961                                             u64 bytenr, u32 blocksize)
 962 {
 963         struct inode *btree_inode = root->fs_info->btree_inode;
 964         struct extent_buffer *eb;
 965         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 966                                 bytenr, blocksize, GFP_NOFS);
 967         return eb;
 968 }
 969
 970 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 971                                                  u64 bytenr, u32 blocksize)
 972 {
 973         struct inode *btree_inode = root->fs_info->btree_inode;
 974         struct extent_buffer *eb;
 975
 976         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 977                                  bytenr, blocksize, NULL, GFP_NOFS);
 978         return eb;
 979 }
 980
 981
 982 int btrfs_write_tree_block(struct extent_buffer *buf)
 983 {
 984         return filemap_fdatawrite_range(buf->first_page->mapping, buf->start,
 985                                         buf->start + buf->len - 1);
 986 }
 987
 988 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
 989 {
 990         return filemap_fdatawait_range(buf->first_page->mapping,
 991                                        buf->start, buf->start + buf->len - 1);
 992 }
 993
 994 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 995                                       u32 blocksize, u64 parent_transid)
 996 {
 997         struct extent_buffer *buf = NULL;
 998         int ret;
 999
1000         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1001         if (!buf)
1002                 return NULL;
1003
1004         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1005
1006         if (ret == 0)
1007                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
1008         return buf;
1009
1010 }
1011
1012 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1013                      struct extent_buffer *buf)
1014 {
1015         struct inode *btree_inode = root->fs_info->btree_inode;
1016         if (btrfs_header_generation(buf) ==
1017             root->fs_info->running_transaction->transid) {
1018                 btrfs_assert_tree_locked(buf);
1019
1020                 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
1021                         spin_lock(&root->fs_info->delalloc_lock);
1022                         if (root->fs_info->dirty_metadata_bytes >= buf->len)
1023                                 root->fs_info->dirty_metadata_bytes -= buf->len;
1024                         else
1025                                 WARN_ON(1);
1026                         spin_unlock(&root->fs_info->delalloc_lock);
1027                 }
1028
1029                 /* ugh, clear_extent_buffer_dirty needs to lock the page */
1030                 btrfs_set_lock_blocking(buf);
1031                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
1032                                           buf);
1033         }
1034         return 0;
1035 }
1036
1037 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
1038                         u32 stripesize, struct btrfs_root *root,
1039                         struct btrfs_fs_info *fs_info,
1040                         u64 objectid)
1041 {
1042         root->node = NULL;
1043         root->commit_root = NULL;
1044         root->sectorsize = sectorsize;
1045         root->nodesize = nodesize;
1046         root->leafsize = leafsize;
1047         root->stripesize = stripesize;
1048         root->ref_cows = 0;
1049         root->track_dirty = 0;
1050         root->in_radix = 0;
1051         root->orphan_item_inserted = 0;
1052         root->orphan_cleanup_state = 0;
1053
1054         root->fs_info = fs_info;
1055         root->objectid = objectid;
1056         root->last_trans = 0;
1057         root->highest_objectid = 0;
1058         root->name = NULL;
1059         root->in_sysfs = 0;
1060         root->inode_tree = RB_ROOT;
1061         root->block_rsv = NULL;
1062         root->orphan_block_rsv = NULL;
1063
1064         INIT_LIST_HEAD(&root->dirty_list);
1065         INIT_LIST_HEAD(&root->orphan_list);
1066         INIT_LIST_HEAD(&root->root_list);
1067         spin_lock_init(&root->node_lock);
1068         spin_lock_init(&root->orphan_lock);
1069         spin_lock_init(&root->inode_lock);
1070         spin_lock_init(&root->accounting_lock);
1071         mutex_init(&root->objectid_mutex);
1072         mutex_init(&root->log_mutex);
1073         init_waitqueue_head(&root->log_writer_wait);
1074         init_waitqueue_head(&root->log_commit_wait[0]);
1075         init_waitqueue_head(&root->log_commit_wait[1]);
1076         atomic_set(&root->log_commit[0], 0);
1077         atomic_set(&root->log_commit[1], 0);
1078         atomic_set(&root->log_writers, 0);
1079         root->log_batch = 0;
1080         root->log_transid = 0;
1081         root->last_log_commit = 0;
1082         extent_io_tree_init(&root->dirty_log_pages,
1083                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1084
1085         memset(&root->root_key, 0, sizeof(root->root_key));
1086         memset(&root->root_item, 0, sizeof(root->root_item));
1087         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
1088         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
1089         root->defrag_trans_start = fs_info->generation;
1090         init_completion(&root->kobj_unregister);
1091         root->defrag_running = 0;
1092         root->root_key.objectid = objectid;
1093         root->anon_super.s_root = NULL;
1094         root->anon_super.s_dev = 0;
1095         INIT_LIST_HEAD(&root->anon_super.s_list);
1096         INIT_LIST_HEAD(&root->anon_super.s_instances);
1097         init_rwsem(&root->anon_super.s_umount);
1098
1099         return 0;
1100 }
1101
1102 static int find_and_setup_root(struct btrfs_root *tree_root,
1103                                struct btrfs_fs_info *fs_info,
1104                                u64 objectid,
1105                                struct btrfs_root *root)
1106 {
1107         int ret;
1108         u32 blocksize;
1109         u64 generation;
1110
1111         __setup_root(tree_root->nodesize, tree_root->leafsize,
1112                      tree_root->sectorsize, tree_root->stripesize,
1113                      root, fs_info, objectid);
1114         ret = btrfs_find_last_root(tree_root, objectid,
1115                                    &root->root_item, &root->root_key);
1116         if (ret > 0)
1117                 return -ENOENT;
1118         BUG_ON(ret);
1119
1120         generation = btrfs_root_generation(&root->root_item);
1121         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1122         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1123                                      blocksize, generation);
1124         if (!root->node || !btrfs_buffer_uptodate(root->node, generation)) {
1125                 free_extent_buffer(root->node);
1126                 return -EIO;
1127         }
1128         root->commit_root = btrfs_root_node(root);
1129         return 0;
1130 }
1131
1132 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1133                                          struct btrfs_fs_info *fs_info)
1134 {
1135         struct btrfs_root *root;
1136         struct btrfs_root *tree_root = fs_info->tree_root;
1137         struct extent_buffer *leaf;
1138
1139         root = kzalloc(sizeof(*root), GFP_NOFS);
1140         if (!root)
1141                 return ERR_PTR(-ENOMEM);
1142
1143         __setup_root(tree_root->nodesize, tree_root->leafsize,
1144                      tree_root->sectorsize, tree_root->stripesize,
1145                      root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1146
1147         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1148         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1149         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1150         /*
1151          * log trees do not get reference counted because they go away
1152          * before a real commit is actually done.  They do store pointers
1153          * to file data extents, and those reference counts still get
1154          * updated (along with back refs to the log tree).
1155          */
1156         root->ref_cows = 0;
1157
1158         leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
1159                                       BTRFS_TREE_LOG_OBJECTID, NULL, 0, 0, 0);
1160         if (IS_ERR(leaf)) {
1161                 kfree(root);
1162                 return ERR_CAST(leaf);
1163         }
1164
1165         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1166         btrfs_set_header_bytenr(leaf, leaf->start);
1167         btrfs_set_header_generation(leaf, trans->transid);
1168         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1169         btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1170         root->node = leaf;
1171
1172         write_extent_buffer(root->node, root->fs_info->fsid,
1173                             (unsigned long)btrfs_header_fsid(root->node),
1174                             BTRFS_FSID_SIZE);
1175         btrfs_mark_buffer_dirty(root->node);
1176         btrfs_tree_unlock(root->node);
1177         return root;
1178 }
1179
1180 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1181                              struct btrfs_fs_info *fs_info)
1182 {
1183         struct btrfs_root *log_root;
1184
1185         log_root = alloc_log_tree(trans, fs_info);
1186         if (IS_ERR(log_root))
1187                 return PTR_ERR(log_root);
1188         WARN_ON(fs_info->log_root_tree);
1189         fs_info->log_root_tree = log_root;
1190         return 0;
1191 }
1192
1193 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1194                        struct btrfs_root *root)
1195 {
1196         struct btrfs_root *log_root;
1197         struct btrfs_inode_item *inode_item;
1198
1199         log_root = alloc_log_tree(trans, root->fs_info);
1200         if (IS_ERR(log_root))
1201                 return PTR_ERR(log_root);
1202
1203         log_root->last_trans = trans->transid;
1204         log_root->root_key.offset = root->root_key.objectid;
1205
1206         inode_item = &log_root->root_item.inode;
1207         inode_item->generation = cpu_to_le64(1);
1208         inode_item->size = cpu_to_le64(3);
1209         inode_item->nlink = cpu_to_le32(1);
1210         inode_item->nbytes = cpu_to_le64(root->leafsize);
1211         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
1212
1213         btrfs_set_root_node(&log_root->root_item, log_root->node);
1214
1215         WARN_ON(root->log_root);
1216         root->log_root = log_root;
1217         root->log_transid = 0;
1218         root->last_log_commit = 0;
1219         return 0;
1220 }
1221
1222 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
1223                                                struct btrfs_key *location)
1224 {
1225         struct btrfs_root *root;
1226         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1227         struct btrfs_path *path;
1228         struct extent_buffer *l;
1229         u64 generation;
1230         u32 blocksize;
1231         int ret = 0;
1232
1233         root = kzalloc(sizeof(*root), GFP_NOFS);
1234         if (!root)
1235                 return ERR_PTR(-ENOMEM);
1236         if (location->offset == (u64)-1) {
1237                 ret = find_and_setup_root(tree_root, fs_info,
1238                                           location->objectid, root);
1239                 if (ret) {
1240                         kfree(root);
1241                         return ERR_PTR(ret);
1242                 }
1243                 goto out;
1244         }
1245
1246         __setup_root(tree_root->nodesize, tree_root->leafsize,
1247                      tree_root->sectorsize, tree_root->stripesize,
1248                      root, fs_info, location->objectid);
1249
1250         path = btrfs_alloc_path();
1251         if (!path) {
1252                 kfree(root);
1253                 return ERR_PTR(-ENOMEM);
1254         }
1255         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
1256         if (ret == 0) {
1257                 l = path->nodes[0];
1258                 read_extent_buffer(l, &root->root_item,
1259                                 btrfs_item_ptr_offset(l, path->slots[0]),
1260                                 sizeof(root->root_item));
1261                 memcpy(&root->root_key, location, sizeof(*location));
1262         }
1263         btrfs_free_path(path);
1264         if (ret) {
1265                 kfree(root);
1266                 if (ret > 0)
1267                         ret = -ENOENT;
1268                 return ERR_PTR(ret);
1269         }
1270
1271         generation = btrfs_root_generation(&root->root_item);
1272         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1273         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1274                                      blocksize, generation);
1275         root->commit_root = btrfs_root_node(root);
1276         BUG_ON(!root->node);
1277 out:
1278         if (location->objectid != BTRFS_TREE_LOG_OBJECTID)
1279                 root->ref_cows = 1;
1280
1281         return root;
1282 }
1283
1284 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1285                                         u64 root_objectid)
1286 {
1287         struct btrfs_root *root;
1288
1289         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
1290                 return fs_info->tree_root;
1291         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
1292                 return fs_info->extent_root;
1293
1294         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1295                                  (unsigned long)root_objectid);
1296         return root;
1297 }
1298
1299 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
1300                                               struct btrfs_key *location)
1301 {
1302         struct btrfs_root *root;
1303         int ret;
1304
1305         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1306                 return fs_info->tree_root;
1307         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1308                 return fs_info->extent_root;
1309         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1310                 return fs_info->chunk_root;
1311         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1312                 return fs_info->dev_root;
1313         if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1314                 return fs_info->csum_root;
1315 again:
1316         spin_lock(&fs_info->fs_roots_radix_lock);
1317         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1318                                  (unsigned long)location->objectid);
1319         spin_unlock(&fs_info->fs_roots_radix_lock);
1320         if (root)
1321                 return root;
1322
1323         root = btrfs_read_fs_root_no_radix(fs_info->tree_root, location);
1324         if (IS_ERR(root))
1325                 return root;
1326
1327         set_anon_super(&root->anon_super, NULL);
1328
1329         if (btrfs_root_refs(&root->root_item) == 0) {
1330                 ret = -ENOENT;
1331                 goto fail;
1332         }
1333
1334         ret = btrfs_find_orphan_item(fs_info->tree_root, location->objectid);
1335         if (ret < 0)
1336                 goto fail;
1337         if (ret == 0)
1338                 root->orphan_item_inserted = 1;
1339
1340         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1341         if (ret)
1342                 goto fail;
1343
1344         spin_lock(&fs_info->fs_roots_radix_lock);
1345         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1346                                 (unsigned long)root->root_key.objectid,
1347                                 root);
1348         if (ret == 0)
1349                 root->in_radix = 1;
1350
1351         spin_unlock(&fs_info->fs_roots_radix_lock);
1352         radix_tree_preload_end();
1353         if (ret) {
1354                 if (ret == -EEXIST) {
1355                         free_fs_root(root);
1356                         goto again;
1357                 }
1358                 goto fail;
1359         }
1360
1361         ret = btrfs_find_dead_roots(fs_info->tree_root,
1362                                     root->root_key.objectid);
1363         WARN_ON(ret);
1364         return root;
1365 fail:
1366         free_fs_root(root);
1367         return ERR_PTR(ret);
1368 }
1369
1370 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
1371                                       struct btrfs_key *location,
1372                                       const char *name, int namelen)
1373 {
1374         return btrfs_read_fs_root_no_name(fs_info, location);
1375 #if 0
1376         struct btrfs_root *root;
1377         int ret;
1378
1379         root = btrfs_read_fs_root_no_name(fs_info, location);
1380         if (!root)
1381                 return NULL;
1382
1383         if (root->in_sysfs)
1384                 return root;
1385
1386         ret = btrfs_set_root_name(root, name, namelen);
1387         if (ret) {
1388                 free_extent_buffer(root->node);
1389                 kfree(root);
1390                 return ERR_PTR(ret);
1391         }
1392
1393         ret = btrfs_sysfs_add_root(root);
1394         if (ret) {
1395                 free_extent_buffer(root->node);
1396                 kfree(root->name);
1397                 kfree(root);
1398                 return ERR_PTR(ret);
1399         }
1400         root->in_sysfs = 1;
1401         return root;
1402 #endif
1403 }
1404
1405 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1406 {
1407         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1408         int ret = 0;
1409         struct btrfs_device *device;
1410         struct backing_dev_info *bdi;
1411
1412         list_for_each_entry(device, &info->fs_devices->devices, dev_list) {
1413                 if (!device->bdev)
1414                         continue;
1415                 bdi = blk_get_backing_dev_info(device->bdev);
1416                 if (bdi && bdi_congested(bdi, bdi_bits)) {
1417                         ret = 1;
1418                         break;
1419                 }
1420         }
1421         return ret;
1422 }
1423
1424 /*
1425  * this unplugs every device on the box, and it is only used when page
1426  * is null
1427  */
1428 static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1429 {
1430         struct btrfs_device *device;
1431         struct btrfs_fs_info *info;
1432
1433         info = (struct btrfs_fs_info *)bdi->unplug_io_data;
1434         list_for_each_entry(device, &info->fs_devices->devices, dev_list) {
1435                 if (!device->bdev)
1436                         continue;
1437
1438                 bdi = blk_get_backing_dev_info(device->bdev);
1439                 if (bdi->unplug_io_fn)
1440                         bdi->unplug_io_fn(bdi, page);
1441         }
1442 }
1443
1444 static void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1445 {
1446         struct inode *inode;
1447         struct extent_map_tree *em_tree;
1448         struct extent_map *em;
1449         struct address_space *mapping;
1450         u64 offset;
1451
1452         /* the generic O_DIRECT read code does this */
1453         if (1 || !page) {
1454                 __unplug_io_fn(bdi, page);
1455                 return;
1456         }
1457
1458         /*
1459          * page->mapping may change at any time.  Get a consistent copy
1460          * and use that for everything below
1461          */
1462         smp_mb();
1463         mapping = page->mapping;
1464         if (!mapping)
1465                 return;
1466
1467         inode = mapping->host;
1468
1469         /*
1470          * don't do the expensive searching for a small number of
1471          * devices
1472          */
1473         if (BTRFS_I(inode)->root->fs_info->fs_devices->open_devices <= 2) {
1474                 __unplug_io_fn(bdi, page);
1475                 return;
1476         }
1477
1478         offset = page_offset(page);
1479
1480         em_tree = &BTRFS_I(inode)->extent_tree;
1481         read_lock(&em_tree->lock);
1482         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
1483         read_unlock(&em_tree->lock);
1484         if (!em) {
1485                 __unplug_io_fn(bdi, page);
1486                 return;
1487         }
1488
1489         if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1490                 free_extent_map(em);
1491                 __unplug_io_fn(bdi, page);
1492                 return;
1493         }
1494         offset = offset - em->start;
1495         btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
1496                           em->block_start + offset, page);
1497         free_extent_map(em);
1498 }
1499
1500 /*
1501  * If this fails, caller must call bdi_destroy() to get rid of the
1502  * bdi again.
1503  */
1504 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1505 {
1506         int err;
1507
1508         bdi->capabilities = BDI_CAP_MAP_COPY;
1509         err = bdi_setup_and_register(bdi, "btrfs", BDI_CAP_MAP_COPY);
1510         if (err)
1511                 return err;
1512
1513         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1514         bdi->unplug_io_fn       = btrfs_unplug_io_fn;
1515         bdi->unplug_io_data     = info;
1516         bdi->congested_fn       = btrfs_congested_fn;
1517         bdi->congested_data     = info;
1518         return 0;
1519 }
1520
1521 static int bio_ready_for_csum(struct bio *bio)
1522 {
1523         u64 length = 0;
1524         u64 buf_len = 0;
1525         u64 start = 0;
1526         struct page *page;
1527         struct extent_io_tree *io_tree = NULL;
1528         struct bio_vec *bvec;
1529         int i;
1530         int ret;
1531
1532         bio_for_each_segment(bvec, bio, i) {
1533                 page = bvec->bv_page;
1534                 if (page->private == EXTENT_PAGE_PRIVATE) {
1535                         length += bvec->bv_len;
1536                         continue;
1537                 }
1538                 if (!page->private) {
1539                         length += bvec->bv_len;
1540                         continue;
1541                 }
1542                 length = bvec->bv_len;
1543                 buf_len = page->private >> 2;
1544                 start = page_offset(page) + bvec->bv_offset;
1545                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1546         }
1547         /* are we fully contained in this bio? */
1548         if (buf_len <= length)
1549                 return 1;
1550
1551         ret = extent_range_uptodate(io_tree, start + length,
1552                                     start + buf_len - 1);
1553         return ret;
1554 }
1555
1556 /*
1557  * called by the kthread helper functions to finally call the bio end_io
1558  * functions.  This is where read checksum verification actually happens
1559  */
1560 static void end_workqueue_fn(struct btrfs_work *work)
1561 {
1562         struct bio *bio;
1563         struct end_io_wq *end_io_wq;
1564         struct btrfs_fs_info *fs_info;
1565         int error;
1566
1567         end_io_wq = container_of(work, struct end_io_wq, work);
1568         bio = end_io_wq->bio;
1569         fs_info = end_io_wq->info;
1570
1571         /* metadata bio reads are special because the whole tree block must
1572          * be checksummed at once.  This makes sure the entire block is in
1573          * ram and up to date before trying to verify things.  For
1574          * blocksize <= pagesize, it is basically a noop
1575          */
1576         if (!(bio->bi_rw & REQ_WRITE) && end_io_wq->metadata &&
1577             !bio_ready_for_csum(bio)) {
1578                 btrfs_queue_worker(&fs_info->endio_meta_workers,
1579                                    &end_io_wq->work);
1580                 return;
1581         }
1582         error = end_io_wq->error;
1583         bio->bi_private = end_io_wq->private;
1584         bio->bi_end_io = end_io_wq->end_io;
1585         kfree(end_io_wq);
1586         bio_endio(bio, error);
1587 }
1588
1589 static int cleaner_kthread(void *arg)
1590 {
1591         struct btrfs_root *root = arg;
1592
1593         do {
1594                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1595
1596                 if (!(root->fs_info->sb->s_flags & MS_RDONLY) &&
1597                     mutex_trylock(&root->fs_info->cleaner_mutex)) {
1598                         btrfs_run_delayed_iputs(root);
1599                         btrfs_clean_old_snapshots(root);
1600                         mutex_unlock(&root->fs_info->cleaner_mutex);
1601                 }
1602
1603                 if (freezing(current)) {
1604                         refrigerator();
1605                 } else {
1606                         set_current_state(TASK_INTERRUPTIBLE);
1607                         if (!kthread_should_stop())
1608                                 schedule();
1609                         __set_current_state(TASK_RUNNING);
1610                 }
1611         } while (!kthread_should_stop());
1612         return 0;
1613 }
1614
1615 static int transaction_kthread(void *arg)
1616 {
1617         struct btrfs_root *root = arg;
1618         struct btrfs_trans_handle *trans;
1619         struct btrfs_transaction *cur;
1620         u64 transid;
1621         unsigned long now;
1622         unsigned long delay;
1623         int ret;
1624
1625         do {
1626                 delay = HZ * 30;
1627                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1628                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1629
1630                 spin_lock(&root->fs_info->new_trans_lock);
1631                 cur = root->fs_info->running_transaction;
1632                 if (!cur) {
1633                         spin_unlock(&root->fs_info->new_trans_lock);
1634                         goto sleep;
1635                 }
1636
1637                 now = get_seconds();
1638                 if (!cur->blocked &&
1639                     (now < cur->start_time || now - cur->start_time < 30)) {
1640                         spin_unlock(&root->fs_info->new_trans_lock);
1641                         delay = HZ * 5;
1642                         goto sleep;
1643                 }
1644                 transid = cur->transid;
1645                 spin_unlock(&root->fs_info->new_trans_lock);
1646
1647                 trans = btrfs_join_transaction(root, 1);
1648                 BUG_ON(IS_ERR(trans));
1649                 if (transid == trans->transid) {
1650                         ret = btrfs_commit_transaction(trans, root);
1651                         BUG_ON(ret);
1652                 } else {
1653                         btrfs_end_transaction(trans, root);
1654                 }
1655 sleep:
1656                 wake_up_process(root->fs_info->cleaner_kthread);
1657                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1658
1659                 if (freezing(current)) {
1660                         refrigerator();
1661                 } else {
1662                         set_current_state(TASK_INTERRUPTIBLE);
1663                         if (!kthread_should_stop() &&
1664                             !btrfs_transaction_blocked(root->fs_info))
1665                                 schedule_timeout(delay);
1666                         __set_current_state(TASK_RUNNING);
1667                 }
1668         } while (!kthread_should_stop());
1669         return 0;
1670 }
1671
1672 struct btrfs_root *open_ctree(struct super_block *sb,
1673                               struct btrfs_fs_devices *fs_devices,
1674                               char *options)
1675 {
1676         u32 sectorsize;
1677         u32 nodesize;
1678         u32 leafsize;
1679         u32 blocksize;
1680         u32 stripesize;
1681         u64 generation;
1682         u64 features;
1683         struct btrfs_key location;
1684         struct buffer_head *bh;
1685         struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
1686                                                  GFP_NOFS);
1687         struct btrfs_root *csum_root = kzalloc(sizeof(struct btrfs_root),
1688                                                  GFP_NOFS);
1689         struct btrfs_root *tree_root = btrfs_sb(sb);
1690         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1691         struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
1692                                                 GFP_NOFS);
1693         struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
1694                                               GFP_NOFS);
1695         struct btrfs_root *log_tree_root;
1696
1697         int ret;
1698         int err = -EINVAL;
1699
1700         struct btrfs_super_block *disk_super;
1701
1702         if (!extent_root || !tree_root || !fs_info ||
1703             !chunk_root || !dev_root || !csum_root) {
1704                 err = -ENOMEM;
1705                 goto fail;
1706         }
1707
1708         ret = init_srcu_struct(&fs_info->subvol_srcu);
1709         if (ret) {
1710                 err = ret;
1711                 goto fail;
1712         }
1713
1714         ret = setup_bdi(fs_info, &fs_info->bdi);
1715         if (ret) {
1716                 err = ret;
1717                 goto fail_srcu;
1718         }
1719
1720         fs_info->btree_inode = new_inode(sb);
1721         if (!fs_info->btree_inode) {
1722                 err = -ENOMEM;
1723                 goto fail_bdi;
1724         }
1725
1726         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
1727         INIT_LIST_HEAD(&fs_info->trans_list);
1728         INIT_LIST_HEAD(&fs_info->dead_roots);
1729         INIT_LIST_HEAD(&fs_info->delayed_iputs);
1730         INIT_LIST_HEAD(&fs_info->hashers);
1731         INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1732         INIT_LIST_HEAD(&fs_info->ordered_operations);
1733         INIT_LIST_HEAD(&fs_info->caching_block_groups);
1734         spin_lock_init(&fs_info->delalloc_lock);
1735         spin_lock_init(&fs_info->new_trans_lock);
1736         spin_lock_init(&fs_info->ref_cache_lock);
1737         spin_lock_init(&fs_info->fs_roots_radix_lock);
1738         spin_lock_init(&fs_info->delayed_iput_lock);
1739
1740         init_completion(&fs_info->kobj_unregister);
1741         fs_info->tree_root = tree_root;
1742         fs_info->extent_root = extent_root;
1743         fs_info->csum_root = csum_root;
1744         fs_info->chunk_root = chunk_root;
1745         fs_info->dev_root = dev_root;
1746         fs_info->fs_devices = fs_devices;
1747         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1748         INIT_LIST_HEAD(&fs_info->space_info);
1749         btrfs_mapping_init(&fs_info->mapping_tree);
1750         btrfs_init_block_rsv(&fs_info->global_block_rsv);
1751         btrfs_init_block_rsv(&fs_info->delalloc_block_rsv);
1752         btrfs_init_block_rsv(&fs_info->trans_block_rsv);
1753         btrfs_init_block_rsv(&fs_info->chunk_block_rsv);
1754         btrfs_init_block_rsv(&fs_info->empty_block_rsv);
1755         INIT_LIST_HEAD(&fs_info->durable_block_rsv_list);
1756         mutex_init(&fs_info->durable_block_rsv_mutex);
1757         atomic_set(&fs_info->nr_async_submits, 0);
1758         atomic_set(&fs_info->async_delalloc_pages, 0);
1759         atomic_set(&fs_info->async_submit_draining, 0);
1760         atomic_set(&fs_info->nr_async_bios, 0);
1761         fs_info->sb = sb;
1762         fs_info->max_inline = 8192 * 1024;
1763         fs_info->metadata_ratio = 0;
1764
1765         fs_info->thread_pool_size = min_t(unsigned long,
1766                                           num_online_cpus() + 2, 8);
1767
1768         INIT_LIST_HEAD(&fs_info->ordered_extents);
1769         spin_lock_init(&fs_info->ordered_extent_lock);
1770
1771         sb->s_blocksize = 4096;
1772         sb->s_blocksize_bits = blksize_bits(4096);
1773         sb->s_bdi = &fs_info->bdi;
1774
1775         fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
1776         fs_info->btree_inode->i_nlink = 1;
1777         /*
1778          * we set the i_size on the btree inode to the max possible int.
1779          * the real end of the address space is determined by all of
1780          * the devices in the system
1781          */
1782         fs_info->btree_inode->i_size = OFFSET_MAX;
1783         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1784         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1785
1786         RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
1787         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1788                              fs_info->btree_inode->i_mapping,
1789                              GFP_NOFS);
1790         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1791                              GFP_NOFS);
1792
1793         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1794
1795         BTRFS_I(fs_info->btree_inode)->root = tree_root;
1796         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1797                sizeof(struct btrfs_key));
1798         BTRFS_I(fs_info->btree_inode)->dummy_inode = 1;
1799         insert_inode_hash(fs_info->btree_inode);
1800
1801         spin_lock_init(&fs_info->block_group_cache_lock);
1802         fs_info->block_group_cache_tree = RB_ROOT;
1803
1804         extent_io_tree_init(&fs_info->freed_extents[0],
1805                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1806         extent_io_tree_init(&fs_info->freed_extents[1],
1807                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1808         fs_info->pinned_extents = &fs_info->freed_extents[0];
1809         fs_info->do_barriers = 1;
1810
1811
1812         mutex_init(&fs_info->trans_mutex);
1813         mutex_init(&fs_info->ordered_operations_mutex);
1814         mutex_init(&fs_info->tree_log_mutex);
1815         mutex_init(&fs_info->chunk_mutex);
1816         mutex_init(&fs_info->transaction_kthread_mutex);
1817         mutex_init(&fs_info->cleaner_mutex);
1818         mutex_init(&fs_info->volume_mutex);
1819         init_rwsem(&fs_info->extent_commit_sem);
1820         init_rwsem(&fs_info->cleanup_work_sem);
1821         init_rwsem(&fs_info->subvol_sem);
1822
1823         btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
1824         btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
1825
1826         init_waitqueue_head(&fs_info->transaction_throttle);
1827         init_waitqueue_head(&fs_info->transaction_wait);
1828         init_waitqueue_head(&fs_info->transaction_blocked_wait);
1829         init_waitqueue_head(&fs_info->async_submit_wait);
1830
1831         __setup_root(4096, 4096, 4096, 4096, tree_root,
1832                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
1833
1834         bh = btrfs_read_dev_super(fs_devices->latest_bdev);
1835         if (!bh) {
1836                 err = -EINVAL;
1837                 goto fail_iput;
1838         }
1839
1840         memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1841         memcpy(&fs_info->super_for_commit, &fs_info->super_copy,
1842                sizeof(fs_info->super_for_commit));
1843         brelse(bh);
1844
1845         memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1846
1847         disk_super = &fs_info->super_copy;
1848         if (!btrfs_super_root(disk_super))
1849                 goto fail_iput;
1850
1851         /* check FS state, whether FS is broken. */
1852         fs_info->fs_state |= btrfs_super_flags(disk_super);
1853
1854         btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
1855
1856         ret = btrfs_parse_options(tree_root, options);
1857         if (ret) {
1858                 err = ret;
1859                 goto fail_iput;
1860         }
1861
1862         features = btrfs_super_incompat_flags(disk_super) &
1863                 ~BTRFS_FEATURE_INCOMPAT_SUPP;
1864         if (features) {
1865                 printk(KERN_ERR "BTRFS: couldn't mount because of "
1866                        "unsupported optional features (%Lx).\n",
1867                        (unsigned long long)features);
1868                 err = -EINVAL;
1869                 goto fail_iput;
1870         }
1871
1872         features = btrfs_super_incompat_flags(disk_super);
1873         features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
1874         if (tree_root->fs_info->compress_type & BTRFS_COMPRESS_LZO)
1875                 features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
1876         btrfs_set_super_incompat_flags(disk_super, features);
1877
1878         features = btrfs_super_compat_ro_flags(disk_super) &
1879                 ~BTRFS_FEATURE_COMPAT_RO_SUPP;
1880         if (!(sb->s_flags & MS_RDONLY) && features) {
1881                 printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
1882                        "unsupported option features (%Lx).\n",
1883                        (unsigned long long)features);
1884                 err = -EINVAL;
1885                 goto fail_iput;
1886         }
1887
1888         btrfs_init_workers(&fs_info->generic_worker,
1889                            "genwork", 1, NULL);
1890
1891         btrfs_init_workers(&fs_info->workers, "worker",
1892                            fs_info->thread_pool_size,
1893                            &fs_info->generic_worker);
1894
1895         btrfs_init_workers(&fs_info->delalloc_workers, "delalloc",
1896                            fs_info->thread_pool_size,
1897                            &fs_info->generic_worker);
1898
1899         btrfs_init_workers(&fs_info->submit_workers, "submit",
1900                            min_t(u64, fs_devices->num_devices,
1901                            fs_info->thread_pool_size),
1902                            &fs_info->generic_worker);
1903
1904         /* a higher idle thresh on the submit workers makes it much more
1905          * likely that bios will be send down in a sane order to the
1906          * devices
1907          */
1908         fs_info->submit_workers.idle_thresh = 64;
1909
1910         fs_info->workers.idle_thresh = 16;
1911         fs_info->workers.ordered = 1;
1912
1913         fs_info->delalloc_workers.idle_thresh = 2;
1914         fs_info->delalloc_workers.ordered = 1;
1915
1916         btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
1917                            &fs_info->generic_worker);
1918         btrfs_init_workers(&fs_info->endio_workers, "endio",
1919                            fs_info->thread_pool_size,
1920                            &fs_info->generic_worker);
1921         btrfs_init_workers(&fs_info->endio_meta_workers, "endio-meta",
1922                            fs_info->thread_pool_size,
1923                            &fs_info->generic_worker);
1924         btrfs_init_workers(&fs_info->endio_meta_write_workers,
1925                            "endio-meta-write", fs_info->thread_pool_size,
1926                            &fs_info->generic_worker);
1927         btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
1928                            fs_info->thread_pool_size,
1929                            &fs_info->generic_worker);
1930         btrfs_init_workers(&fs_info->endio_freespace_worker, "freespace-write",
1931                            1, &fs_info->generic_worker);
1932
1933         /*
1934          * endios are largely parallel and should have a very
1935          * low idle thresh
1936          */
1937         fs_info->endio_workers.idle_thresh = 4;
1938         fs_info->endio_meta_workers.idle_thresh = 4;
1939
1940         fs_info->endio_write_workers.idle_thresh = 2;
1941         fs_info->endio_meta_write_workers.idle_thresh = 2;
1942
1943         btrfs_start_workers(&fs_info->workers, 1);
1944         btrfs_start_workers(&fs_info->generic_worker, 1);
1945         btrfs_start_workers(&fs_info->submit_workers, 1);
1946         btrfs_start_workers(&fs_info->delalloc_workers, 1);
1947         btrfs_start_workers(&fs_info->fixup_workers, 1);
1948         btrfs_start_workers(&fs_info->endio_workers, 1);
1949         btrfs_start_workers(&fs_info->endio_meta_workers, 1);
1950         btrfs_start_workers(&fs_info->endio_meta_write_workers, 1);
1951         btrfs_start_workers(&fs_info->endio_write_workers, 1);
1952         btrfs_start_workers(&fs_info->endio_freespace_worker, 1);
1953
1954         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1955         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
1956                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
1957
1958         nodesize = btrfs_super_nodesize(disk_super);
1959         leafsize = btrfs_super_leafsize(disk_super);
1960         sectorsize = btrfs_super_sectorsize(disk_super);
1961         stripesize = btrfs_super_stripesize(disk_super);
1962         tree_root->nodesize = nodesize;
1963         tree_root->leafsize = leafsize;
1964         tree_root->sectorsize = sectorsize;
1965         tree_root->stripesize = stripesize;
1966
1967         sb->s_blocksize = sectorsize;
1968         sb->s_blocksize_bits = blksize_bits(sectorsize);
1969
1970         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1971                     sizeof(disk_super->magic))) {
1972                 printk(KERN_INFO "btrfs: valid FS not found on %s\n", sb->s_id);
1973                 goto fail_sb_buffer;
1974         }
1975
1976         mutex_lock(&fs_info->chunk_mutex);
1977         ret = btrfs_read_sys_array(tree_root);
1978         mutex_unlock(&fs_info->chunk_mutex);
1979         if (ret) {
1980                 printk(KERN_WARNING "btrfs: failed to read the system "
1981                        "array on %s\n", sb->s_id);
1982                 goto fail_sb_buffer;
1983         }
1984
1985         blocksize = btrfs_level_size(tree_root,
1986                                      btrfs_super_chunk_root_level(disk_super));
1987         generation = btrfs_super_chunk_root_generation(disk_super);
1988
1989         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1990                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1991
1992         chunk_root->node = read_tree_block(chunk_root,
1993                                            btrfs_super_chunk_root(disk_super),
1994                                            blocksize, generation);
1995         BUG_ON(!chunk_root->node);
1996         if (!test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
1997                 printk(KERN_WARNING "btrfs: failed to read chunk root on %s\n",
1998                        sb->s_id);
1999                 goto fail_chunk_root;
2000         }
2001         btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
2002         chunk_root->commit_root = btrfs_root_node(chunk_root);
2003
2004         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
2005            (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
2006            BTRFS_UUID_SIZE);
2007
2008         mutex_lock(&fs_info->chunk_mutex);
2009         ret = btrfs_read_chunk_tree(chunk_root);
2010         mutex_unlock(&fs_info->chunk_mutex);
2011         if (ret) {
2012                 printk(KERN_WARNING "btrfs: failed to read chunk tree on %s\n",
2013                        sb->s_id);
2014                 goto fail_chunk_root;
2015         }
2016
2017         btrfs_close_extra_devices(fs_devices);
2018
2019         blocksize = btrfs_level_size(tree_root,
2020                                      btrfs_super_root_level(disk_super));
2021         generation = btrfs_super_generation(disk_super);
2022
2023         tree_root->node = read_tree_block(tree_root,
2024                                           btrfs_super_root(disk_super),
2025                                           blocksize, generation);
2026         if (!tree_root->node)
2027                 goto fail_chunk_root;
2028         if (!test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
2029                 printk(KERN_WARNING "btrfs: failed to read tree root on %s\n",
2030                        sb->s_id);
2031                 goto fail_tree_root;
2032         }
2033         btrfs_set_root_node(&tree_root->root_item, tree_root->node);
2034         tree_root->commit_root = btrfs_root_node(tree_root);
2035
2036         ret = find_and_setup_root(tree_root, fs_info,
2037                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
2038         if (ret)
2039                 goto fail_tree_root;
2040         extent_root->track_dirty = 1;
2041
2042         ret = find_and_setup_root(tree_root, fs_info,
2043                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
2044         if (ret)
2045                 goto fail_extent_root;
2046         dev_root->track_dirty = 1;
2047
2048         ret = find_and_setup_root(tree_root, fs_info,
2049                                   BTRFS_CSUM_TREE_OBJECTID, csum_root);
2050         if (ret)
2051                 goto fail_dev_root;
2052
2053         csum_root->track_dirty = 1;
2054
2055         fs_info->generation = generation;
2056         fs_info->last_trans_committed = generation;
2057         fs_info->data_alloc_profile = (u64)-1;
2058         fs_info->metadata_alloc_profile = (u64)-1;
2059         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
2060
2061         ret = btrfs_read_block_groups(extent_root);
2062         if (ret) {
2063                 printk(KERN_ERR "Failed to read block groups: %d\n", ret);
2064                 goto fail_block_groups;
2065         }
2066
2067         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
2068                                                "btrfs-cleaner");
2069         if (IS_ERR(fs_info->cleaner_kthread))
2070                 goto fail_block_groups;
2071
2072         fs_info->transaction_kthread = kthread_run(transaction_kthread,
2073                                                    tree_root,
2074                                                    "btrfs-transaction");
2075         if (IS_ERR(fs_info->transaction_kthread))
2076                 goto fail_cleaner;
2077
2078         if (!btrfs_test_opt(tree_root, SSD) &&
2079             !btrfs_test_opt(tree_root, NOSSD) &&
2080             !fs_info->fs_devices->rotating) {
2081                 printk(KERN_INFO "Btrfs detected SSD devices, enabling SSD "
2082                        "mode\n");
2083                 btrfs_set_opt(fs_info->mount_opt, SSD);
2084         }
2085
2086         /* do not make disk changes in broken FS */
2087         if (btrfs_super_log_root(disk_super) != 0 &&
2088             !(fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)) {
2089                 u64 bytenr = btrfs_super_log_root(disk_super);
2090
2091                 if (fs_devices->rw_devices == 0) {
2092                         printk(KERN_WARNING "Btrfs log replay required "
2093                                "on RO media\n");
2094                         err = -EIO;
2095                         goto fail_trans_kthread;
2096                 }
2097                 blocksize =
2098                      btrfs_level_size(tree_root,
2099                                       btrfs_super_log_root_level(disk_super));
2100
2101                 log_tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
2102                 if (!log_tree_root) {
2103                         err = -ENOMEM;
2104                         goto fail_trans_kthread;
2105                 }
2106
2107                 __setup_root(nodesize, leafsize, sectorsize, stripesize,
2108                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
2109
2110                 log_tree_root->node = read_tree_block(tree_root, bytenr,
2111                                                       blocksize,
2112                                                       generation + 1);
2113                 ret = btrfs_recover_log_trees(log_tree_root);
2114                 BUG_ON(ret);
2115
2116                 if (sb->s_flags & MS_RDONLY) {
2117                         ret =  btrfs_commit_super(tree_root);
2118                         BUG_ON(ret);
2119                 }
2120         }
2121
2122         ret = btrfs_find_orphan_roots(tree_root);
2123         BUG_ON(ret);
2124
2125         if (!(sb->s_flags & MS_RDONLY)) {
2126                 ret = btrfs_cleanup_fs_roots(fs_info);
2127                 BUG_ON(ret);
2128
2129                 ret = btrfs_recover_relocation(tree_root);
2130                 if (ret < 0) {
2131                         printk(KERN_WARNING
2132                                "btrfs: failed to recover relocation\n");
2133                         err = -EINVAL;
2134                         goto fail_trans_kthread;
2135                 }
2136         }
2137
2138         location.objectid = BTRFS_FS_TREE_OBJECTID;
2139         location.type = BTRFS_ROOT_ITEM_KEY;
2140         location.offset = (u64)-1;
2141
2142         fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
2143         if (!fs_info->fs_root)
2144                 goto fail_trans_kthread;
2145         if (IS_ERR(fs_info->fs_root)) {
2146                 err = PTR_ERR(fs_info->fs_root);
2147                 goto fail_trans_kthread;
2148         }
2149
2150         if (!(sb->s_flags & MS_RDONLY)) {
2151                 down_read(&fs_info->cleanup_work_sem);
2152                 err = btrfs_orphan_cleanup(fs_info->fs_root);
2153                 if (!err)
2154                         err = btrfs_orphan_cleanup(fs_info->tree_root);
2155                 up_read(&fs_info->cleanup_work_sem);
2156                 if (err) {
2157                         close_ctree(tree_root);
2158                         return ERR_PTR(err);
2159                 }
2160         }
2161
2162         return tree_root;
2163
2164 fail_trans_kthread:
2165         kthread_stop(fs_info->transaction_kthread);
2166 fail_cleaner:
2167         kthread_stop(fs_info->cleaner_kthread);
2168
2169         /*
2170          * make sure we're done with the btree inode before we stop our
2171          * kthreads
2172          */
2173         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
2174         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2175
2176 fail_block_groups:
2177         btrfs_free_block_groups(fs_info);
2178         free_extent_buffer(csum_root->node);
2179         free_extent_buffer(csum_root->commit_root);
2180 fail_dev_root:
2181         free_extent_buffer(dev_root->node);
2182         free_extent_buffer(dev_root->commit_root);
2183 fail_extent_root:
2184         free_extent_buffer(extent_root->node);
2185         free_extent_buffer(extent_root->commit_root);
2186 fail_tree_root:
2187         free_extent_buffer(tree_root->node);
2188         free_extent_buffer(tree_root->commit_root);
2189 fail_chunk_root:
2190         free_extent_buffer(chunk_root->node);
2191         free_extent_buffer(chunk_root->commit_root);
2192 fail_sb_buffer:
2193         btrfs_stop_workers(&fs_info->generic_worker);
2194         btrfs_stop_workers(&fs_info->fixup_workers);
2195         btrfs_stop_workers(&fs_info->delalloc_workers);
2196         btrfs_stop_workers(&fs_info->workers);
2197         btrfs_stop_workers(&fs_info->endio_workers);
2198         btrfs_stop_workers(&fs_info->endio_meta_workers);
2199         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2200         btrfs_stop_workers(&fs_info->endio_write_workers);
2201         btrfs_stop_workers(&fs_info->endio_freespace_worker);
2202         btrfs_stop_workers(&fs_info->submit_workers);
2203 fail_iput:
2204         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2205         iput(fs_info->btree_inode);
2206
2207         btrfs_close_devices(fs_info->fs_devices);
2208         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2209 fail_bdi:
2210         bdi_destroy(&fs_info->bdi);
2211 fail_srcu:
2212         cleanup_srcu_struct(&fs_info->subvol_srcu);
2213 fail:
2214         kfree(extent_root);
2215         kfree(tree_root);
2216         kfree(fs_info);
2217         kfree(chunk_root);
2218         kfree(dev_root);
2219         kfree(csum_root);
2220         return ERR_PTR(err);
2221 }
2222
2223 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
2224 {
2225         char b[BDEVNAME_SIZE];
2226
2227         if (uptodate) {
2228                 set_buffer_uptodate(bh);
2229         } else {
2230                 if (printk_ratelimit()) {
2231                         printk(KERN_WARNING "lost page write due to "
2232                                         "I/O error on %s\n",
2233                                        bdevname(bh->b_bdev, b));
2234                 }
2235                 /* note, we dont' set_buffer_write_io_error because we have
2236                  * our own ways of dealing with the IO errors
2237                  */
2238                 clear_buffer_uptodate(bh);
2239         }
2240         unlock_buffer(bh);
2241         put_bh(bh);
2242 }
2243
2244 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
2245 {
2246         struct buffer_head *bh;
2247         struct buffer_head *latest = NULL;
2248         struct btrfs_super_block *super;
2249         int i;
2250         u64 transid = 0;
2251         u64 bytenr;
2252
2253         /* we would like to check all the supers, but that would make
2254          * a btrfs mount succeed after a mkfs from a different FS.
2255          * So, we need to add a special mount option to scan for
2256          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
2257          */
2258         for (i = 0; i < 1; i++) {
2259                 bytenr = btrfs_sb_offset(i);
2260                 if (bytenr + 4096 >= i_size_read(bdev->bd_inode))
2261                         break;
2262                 bh = __bread(bdev, bytenr / 4096, 4096);
2263                 if (!bh)
2264                         continue;
2265
2266                 super = (struct btrfs_super_block *)bh->b_data;
2267                 if (btrfs_super_bytenr(super) != bytenr ||
2268                     strncmp((char *)(&super->magic), BTRFS_MAGIC,
2269                             sizeof(super->magic))) {
2270                         brelse(bh);
2271                         continue;
2272                 }
2273
2274                 if (!latest || btrfs_super_generation(super) > transid) {
2275                         brelse(latest);
2276                         latest = bh;
2277                         transid = btrfs_super_generation(super);
2278                 } else {
2279                         brelse(bh);
2280                 }
2281         }
2282         return latest;
2283 }
2284
2285 /*
2286  * this should be called twice, once with wait == 0 and
2287  * once with wait == 1.  When wait == 0 is done, all the buffer heads
2288  * we write are pinned.
2289  *
2290  * They are released when wait == 1 is done.
2291  * max_mirrors must be the same for both runs, and it indicates how
2292  * many supers on this one device should be written.
2293  *
2294  * max_mirrors == 0 means to write them all.
2295  */
2296 static int write_dev_supers(struct btrfs_device *device,
2297                             struct btrfs_super_block *sb,
2298                             int do_barriers, int wait, int max_mirrors)
2299 {
2300         struct buffer_head *bh;
2301         int i;
2302         int ret;
2303         int errors = 0;
2304         u32 crc;
2305         u64 bytenr;
2306         int last_barrier = 0;
2307
2308         if (max_mirrors == 0)
2309                 max_mirrors = BTRFS_SUPER_MIRROR_MAX;
2310
2311         /* make sure only the last submit_bh does a barrier */
2312         if (do_barriers) {
2313                 for (i = 0; i < max_mirrors; i++) {
2314                         bytenr = btrfs_sb_offset(i);
2315                         if (bytenr + BTRFS_SUPER_INFO_SIZE >=
2316                             device->total_bytes)
2317                                 break;
2318                         last_barrier = i;
2319                 }
2320         }
2321
2322         for (i = 0; i < max_mirrors; i++) {
2323                 bytenr = btrfs_sb_offset(i);
2324                 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
2325                         break;
2326
2327                 if (wait) {
2328                         bh = __find_get_block(device->bdev, bytenr / 4096,
2329                                               BTRFS_SUPER_INFO_SIZE);
2330                         BUG_ON(!bh);
2331                         wait_on_buffer(bh);
2332                         if (!buffer_uptodate(bh))
2333                                 errors++;
2334
2335                         /* drop our reference */
2336                         brelse(bh);
2337
2338                         /* drop the reference from the wait == 0 run */
2339                         brelse(bh);
2340                         continue;
2341                 } else {
2342                         btrfs_set_super_bytenr(sb, bytenr);
2343
2344                         crc = ~(u32)0;
2345                         crc = btrfs_csum_data(NULL, (char *)sb +
2346                                               BTRFS_CSUM_SIZE, crc,
2347                                               BTRFS_SUPER_INFO_SIZE -
2348                                               BTRFS_CSUM_SIZE);
2349                         btrfs_csum_final(crc, sb->csum);
2350
2351                         /*
2352                          * one reference for us, and we leave it for the
2353                          * caller
2354                          */
2355                         bh = __getblk(device->bdev, bytenr / 4096,
2356                                       BTRFS_SUPER_INFO_SIZE);
2357                         memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
2358
2359                         /* one reference for submit_bh */
2360                         get_bh(bh);
2361
2362                         set_buffer_uptodate(bh);
2363                         lock_buffer(bh);
2364                         bh->b_end_io = btrfs_end_buffer_write_sync;
2365                 }
2366
2367                 if (i == last_barrier && do_barriers)
2368                         ret = submit_bh(WRITE_FLUSH_FUA, bh);
2369                 else
2370                         ret = submit_bh(WRITE_SYNC, bh);
2371
2372                 if (ret)
2373                         errors++;
2374         }
2375         return errors < i ? 0 : -1;
2376 }
2377
2378 int write_all_supers(struct btrfs_root *root, int max_mirrors)
2379 {
2380         struct list_head *head;
2381         struct btrfs_device *dev;
2382         struct btrfs_super_block *sb;
2383         struct btrfs_dev_item *dev_item;
2384         int ret;
2385         int do_barriers;
2386         int max_errors;
2387         int total_errors = 0;
2388         u64 flags;
2389
2390         max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
2391         do_barriers = !btrfs_test_opt(root, NOBARRIER);
2392
2393         sb = &root->fs_info->super_for_commit;
2394         dev_item = &sb->dev_item;
2395
2396         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2397         head = &root->fs_info->fs_devices->devices;
2398         list_for_each_entry(dev, head, dev_list) {
2399                 if (!dev->bdev) {
2400                         total_errors++;
2401                         continue;
2402                 }
2403                 if (!dev->in_fs_metadata || !dev->writeable)
2404                         continue;
2405
2406                 btrfs_set_stack_device_generation(dev_item, 0);
2407                 btrfs_set_stack_device_type(dev_item, dev->type);
2408                 btrfs_set_stack_device_id(dev_item, dev->devid);
2409                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
2410                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
2411                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
2412                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
2413                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
2414                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
2415                 memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
2416
2417                 flags = btrfs_super_flags(sb);
2418                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
2419
2420                 ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
2421                 if (ret)
2422                         total_errors++;
2423         }
2424         if (total_errors > max_errors) {
2425                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2426                        total_errors);
2427                 BUG();
2428         }
2429
2430         total_errors = 0;
2431         list_for_each_entry(dev, head, dev_list) {
2432                 if (!dev->bdev)
2433                         continue;
2434                 if (!dev->in_fs_metadata || !dev->writeable)
2435                         continue;
2436
2437                 ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
2438                 if (ret)
2439                         total_errors++;
2440         }
2441         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2442         if (total_errors > max_errors) {
2443                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2444                        total_errors);
2445                 BUG();
2446         }
2447         return 0;
2448 }
2449
2450 int write_ctree_super(struct btrfs_trans_handle *trans,
2451                       struct btrfs_root *root, int max_mirrors)
2452 {
2453         int ret;
2454
2455         ret = write_all_supers(root, max_mirrors);
2456         return ret;
2457 }
2458
2459 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2460 {
2461         spin_lock(&fs_info->fs_roots_radix_lock);
2462         radix_tree_delete(&fs_info->fs_roots_radix,
2463                           (unsigned long)root->root_key.objectid);
2464         spin_unlock(&fs_info->fs_roots_radix_lock);
2465
2466         if (btrfs_root_refs(&root->root_item) == 0)
2467                 synchronize_srcu(&fs_info->subvol_srcu);
2468
2469         free_fs_root(root);
2470         return 0;
2471 }
2472
2473 static void free_fs_root(struct btrfs_root *root)
2474 {
2475         WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
2476         if (root->anon_super.s_dev) {
2477                 down_write(&root->anon_super.s_umount);
2478                 kill_anon_super(&root->anon_super);
2479         }
2480         free_extent_buffer(root->node);
2481         free_extent_buffer(root->commit_root);
2482         kfree(root->name);
2483         kfree(root);
2484 }
2485
2486 static int del_fs_roots(struct btrfs_fs_info *fs_info)
2487 {
2488         int ret;
2489         struct btrfs_root *gang[8];
2490         int i;
2491
2492         while (!list_empty(&fs_info->dead_roots)) {
2493                 gang[0] = list_entry(fs_info->dead_roots.next,
2494                                      struct btrfs_root, root_list);
2495                 list_del(&gang[0]->root_list);
2496
2497                 if (gang[0]->in_radix) {
2498                         btrfs_free_fs_root(fs_info, gang[0]);
2499                 } else {
2500                         free_extent_buffer(gang[0]->node);
2501                         free_extent_buffer(gang[0]->commit_root);
2502                         kfree(gang[0]);
2503                 }
2504         }
2505
2506         while (1) {
2507                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2508                                              (void **)gang, 0,
2509                                              ARRAY_SIZE(gang));
2510                 if (!ret)
2511                         break;
2512                 for (i = 0; i < ret; i++)
2513                         btrfs_free_fs_root(fs_info, gang[i]);
2514         }
2515         return 0;
2516 }
2517
2518 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
2519 {
2520         u64 root_objectid = 0;
2521         struct btrfs_root *gang[8];
2522         int i;
2523         int ret;
2524
2525         while (1) {
2526                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2527                                              (void **)gang, root_objectid,
2528                                              ARRAY_SIZE(gang));
2529                 if (!ret)
2530                         break;
2531
2532                 root_objectid = gang[ret - 1]->root_key.objectid + 1;
2533                 for (i = 0; i < ret; i++) {
2534                         int err;
2535
2536                         root_objectid = gang[i]->root_key.objectid;
2537                         err = btrfs_orphan_cleanup(gang[i]);
2538                         if (err)
2539                                 return err;
2540                 }
2541                 root_objectid++;
2542         }
2543         return 0;
2544 }
2545
2546 int btrfs_commit_super(struct btrfs_root *root)
2547 {
2548         struct btrfs_trans_handle *trans;
2549         int ret;
2550
2551         mutex_lock(&root->fs_info->cleaner_mutex);
2552         btrfs_run_delayed_iputs(root);
2553         btrfs_clean_old_snapshots(root);
2554         mutex_unlock(&root->fs_info->cleaner_mutex);
2555
2556         /* wait until ongoing cleanup work done */
2557         down_write(&root->fs_info->cleanup_work_sem);
2558         up_write(&root->fs_info->cleanup_work_sem);
2559
2560         trans = btrfs_join_transaction(root, 1);
2561         if (IS_ERR(trans))
2562                 return PTR_ERR(trans);
2563         ret = btrfs_commit_transaction(trans, root);
2564         BUG_ON(ret);
2565         /* run commit again to drop the original snapshot */
2566         trans = btrfs_join_transaction(root, 1);
2567         if (IS_ERR(trans))
2568                 return PTR_ERR(trans);
2569         btrfs_commit_transaction(trans, root);
2570         ret = btrfs_write_and_wait_transaction(NULL, root);
2571         BUG_ON(ret);
2572
2573         ret = write_ctree_super(NULL, root, 0);
2574         return ret;
2575 }
2576
2577 int close_ctree(struct btrfs_root *root)
2578 {
2579         struct btrfs_fs_info *fs_info = root->fs_info;
2580         int ret;
2581
2582         fs_info->closing = 1;
2583         smp_mb();
2584
2585         btrfs_put_block_group_cache(fs_info);
2586
2587         /*
2588          * Here come 2 situations when btrfs is broken to flip readonly:
2589          *
2590          * 1. when btrfs flips readonly somewhere else before
2591          * btrfs_commit_super, sb->s_flags has MS_RDONLY flag,
2592          * and btrfs will skip to write sb directly to keep
2593          * ERROR state on disk.
2594          *
2595          * 2. when btrfs flips readonly just in btrfs_commit_super,
2596          * and in such case, btrfs cannnot write sb via btrfs_commit_super,
2597          * and since fs_state has been set BTRFS_SUPER_FLAG_ERROR flag,
2598          * btrfs will cleanup all FS resources first and write sb then.
2599          */
2600         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
2601                 ret = btrfs_commit_super(root);
2602                 if (ret)
2603                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
2604         }
2605
2606         if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
2607                 ret = btrfs_error_commit_super(root);
2608                 if (ret)
2609                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
2610         }
2611
2612         kthread_stop(root->fs_info->transaction_kthread);
2613         kthread_stop(root->fs_info->cleaner_kthread);
2614
2615         fs_info->closing = 2;
2616         smp_mb();
2617
2618         if (fs_info->delalloc_bytes) {
2619                 printk(KERN_INFO "btrfs: at unmount delalloc count %llu\n",
2620                        (unsigned long long)fs_info->delalloc_bytes);
2621         }
2622         if (fs_info->total_ref_cache_size) {
2623                 printk(KERN_INFO "btrfs: at umount reference cache size %llu\n",
2624                        (unsigned long long)fs_info->total_ref_cache_size);
2625         }
2626
2627         free_extent_buffer(fs_info->extent_root->node);
2628         free_extent_buffer(fs_info->extent_root->commit_root);
2629         free_extent_buffer(fs_info->tree_root->node);
2630         free_extent_buffer(fs_info->tree_root->commit_root);
2631         free_extent_buffer(root->fs_info->chunk_root->node);
2632         free_extent_buffer(root->fs_info->chunk_root->commit_root);
2633         free_extent_buffer(root->fs_info->dev_root->node);
2634         free_extent_buffer(root->fs_info->dev_root->commit_root);
2635         free_extent_buffer(root->fs_info->csum_root->node);
2636         free_extent_buffer(root->fs_info->csum_root->commit_root);
2637
2638         btrfs_free_block_groups(root->fs_info);
2639
2640         del_fs_roots(fs_info);
2641
2642         iput(fs_info->btree_inode);
2643
2644         btrfs_stop_workers(&fs_info->generic_worker);
2645         btrfs_stop_workers(&fs_info->fixup_workers);
2646         btrfs_stop_workers(&fs_info->delalloc_workers);
2647         btrfs_stop_workers(&fs_info->workers);
2648         btrfs_stop_workers(&fs_info->endio_workers);
2649         btrfs_stop_workers(&fs_info->endio_meta_workers);
2650         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2651         btrfs_stop_workers(&fs_info->endio_write_workers);
2652         btrfs_stop_workers(&fs_info->endio_freespace_worker);
2653         btrfs_stop_workers(&fs_info->submit_workers);
2654
2655         btrfs_close_devices(fs_info->fs_devices);
2656         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2657
2658         bdi_destroy(&fs_info->bdi);
2659         cleanup_srcu_struct(&fs_info->subvol_srcu);
2660
2661         kfree(fs_info->extent_root);
2662         kfree(fs_info->tree_root);
2663         kfree(fs_info->chunk_root);
2664         kfree(fs_info->dev_root);
2665         kfree(fs_info->csum_root);
2666         kfree(fs_info);
2667
2668         return 0;
2669 }
2670
2671 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
2672 {
2673         int ret;
2674         struct inode *btree_inode = buf->first_page->mapping->host;
2675
2676         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf,
2677                                      NULL);
2678         if (!ret)
2679                 return ret;
2680
2681         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
2682                                     parent_transid);
2683         return !ret;
2684 }
2685
2686 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
2687 {
2688         struct inode *btree_inode = buf->first_page->mapping->host;
2689         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
2690                                           buf);
2691 }
2692
2693 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
2694 {
2695         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2696         u64 transid = btrfs_header_generation(buf);
2697         struct inode *btree_inode = root->fs_info->btree_inode;
2698         int was_dirty;
2699
2700         btrfs_assert_tree_locked(buf);
2701         if (transid != root->fs_info->generation) {
2702                 printk(KERN_CRIT "btrfs transid mismatch buffer %llu, "
2703                        "found %llu running %llu\n",
2704                         (unsigned long long)buf->start,
2705                         (unsigned long long)transid,
2706                         (unsigned long long)root->fs_info->generation);
2707                 WARN_ON(1);
2708         }
2709         was_dirty = set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
2710                                             buf);
2711         if (!was_dirty) {
2712                 spin_lock(&root->fs_info->delalloc_lock);
2713                 root->fs_info->dirty_metadata_bytes += buf->len;
2714                 spin_unlock(&root->fs_info->delalloc_lock);
2715         }
2716 }
2717
2718 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
2719 {
2720         /*
2721          * looks as though older kernels can get into trouble with
2722          * this code, they end up stuck in balance_dirty_pages forever
2723          */
2724         u64 num_dirty;
2725         unsigned long thresh = 32 * 1024 * 1024;
2726
2727         if (current->flags & PF_MEMALLOC)
2728                 return;
2729
2730         num_dirty = root->fs_info->dirty_metadata_bytes;
2731
2732         if (num_dirty > thresh) {
2733                 balance_dirty_pages_ratelimited_nr(
2734                                    root->fs_info->btree_inode->i_mapping, 1);
2735         }
2736         return;
2737 }
2738
2739 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
2740 {
2741         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2742         int ret;
2743         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
2744         if (ret == 0)
2745                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
2746         return ret;
2747 }
2748
2749 int btree_lock_page_hook(struct page *page)
2750 {
2751         struct inode *inode = page->mapping->host;
2752         struct btrfs_root *root = BTRFS_I(inode)->root;
2753         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2754         struct extent_buffer *eb;
2755         unsigned long len;
2756         u64 bytenr = page_offset(page);
2757
2758         if (page->private == EXTENT_PAGE_PRIVATE)
2759                 goto out;
2760
2761         len = page->private >> 2;
2762         eb = find_extent_buffer(io_tree, bytenr, len, GFP_NOFS);
2763         if (!eb)
2764                 goto out;
2765
2766         btrfs_tree_lock(eb);
2767         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
2768
2769         if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
2770                 spin_lock(&root->fs_info->delalloc_lock);
2771                 if (root->fs_info->dirty_metadata_bytes >= eb->len)
2772                         root->fs_info->dirty_metadata_bytes -= eb->len;
2773                 else
2774                         WARN_ON(1);
2775                 spin_unlock(&root->fs_info->delalloc_lock);
2776         }
2777
2778         btrfs_tree_unlock(eb);
2779         free_extent_buffer(eb);
2780 out:
2781         lock_page(page);
2782         return 0;
2783 }
2784
2785 static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
2786                               int read_only)
2787 {
2788         if (read_only)
2789                 return;
2790
2791         if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
2792                 printk(KERN_WARNING "warning: mount fs with errors, "
2793                        "running btrfsck is recommended\n");
2794 }
2795
2796 int btrfs_error_commit_super(struct btrfs_root *root)
2797 {
2798         int ret;
2799
2800         mutex_lock(&root->fs_info->cleaner_mutex);
2801         btrfs_run_delayed_iputs(root);
2802         mutex_unlock(&root->fs_info->cleaner_mutex);
2803
2804         down_write(&root->fs_info->cleanup_work_sem);
2805         up_write(&root->fs_info->cleanup_work_sem);
2806
2807         /* cleanup FS via transaction */
2808         btrfs_cleanup_transaction(root);
2809
2810         ret = write_ctree_super(NULL, root, 0);
2811
2812         return ret;
2813 }
2814
2815 static int btrfs_destroy_ordered_operations(struct btrfs_root *root)
2816 {
2817         struct btrfs_inode *btrfs_inode;
2818         struct list_head splice;
2819
2820         INIT_LIST_HEAD(&splice);
2821
2822         mutex_lock(&root->fs_info->ordered_operations_mutex);
2823         spin_lock(&root->fs_info->ordered_extent_lock);
2824
2825         list_splice_init(&root->fs_info->ordered_operations, &splice);
2826         while (!list_empty(&splice)) {
2827                 btrfs_inode = list_entry(splice.next, struct btrfs_inode,
2828                                          ordered_operations);
2829
2830                 list_del_init(&btrfs_inode->ordered_operations);
2831
2832                 btrfs_invalidate_inodes(btrfs_inode->root);
2833         }
2834
2835         spin_unlock(&root->fs_info->ordered_extent_lock);
2836         mutex_unlock(&root->fs_info->ordered_operations_mutex);
2837
2838         return 0;
2839 }
2840
2841 static int btrfs_destroy_ordered_extents(struct btrfs_root *root)
2842 {
2843         struct list_head splice;
2844         struct btrfs_ordered_extent *ordered;
2845         struct inode *inode;
2846
2847         INIT_LIST_HEAD(&splice);
2848
2849         spin_lock(&root->fs_info->ordered_extent_lock);
2850
2851         list_splice_init(&root->fs_info->ordered_extents, &splice);
2852         while (!list_empty(&splice)) {
2853                 ordered = list_entry(splice.next, struct btrfs_ordered_extent,
2854                                      root_extent_list);
2855
2856                 list_del_init(&ordered->root_extent_list);
2857                 atomic_inc(&ordered->refs);
2858
2859                 /* the inode may be getting freed (in sys_unlink path). */
2860                 inode = igrab(ordered->inode);
2861
2862                 spin_unlock(&root->fs_info->ordered_extent_lock);
2863                 if (inode)
2864                         iput(inode);
2865
2866                 atomic_set(&ordered->refs, 1);
2867                 btrfs_put_ordered_extent(ordered);
2868
2869                 spin_lock(&root->fs_info->ordered_extent_lock);
2870         }
2871
2872         spin_unlock(&root->fs_info->ordered_extent_lock);
2873
2874         return 0;
2875 }
2876
2877 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
2878                                       struct btrfs_root *root)
2879 {
2880         struct rb_node *node;
2881         struct btrfs_delayed_ref_root *delayed_refs;
2882         struct btrfs_delayed_ref_node *ref;
2883         int ret = 0;
2884
2885         delayed_refs = &trans->delayed_refs;
2886
2887         spin_lock(&delayed_refs->lock);
2888         if (delayed_refs->num_entries == 0) {
2889                 printk(KERN_INFO "delayed_refs has NO entry\n");
2890                 return ret;
2891         }
2892
2893         node = rb_first(&delayed_refs->root);
2894         while (node) {
2895                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2896                 node = rb_next(node);
2897
2898                 ref->in_tree = 0;
2899                 rb_erase(&ref->rb_node, &delayed_refs->root);
2900                 delayed_refs->num_entries--;
2901
2902                 atomic_set(&ref->refs, 1);
2903                 if (btrfs_delayed_ref_is_head(ref)) {
2904                         struct btrfs_delayed_ref_head *head;
2905
2906                         head = btrfs_delayed_node_to_head(ref);
2907                         mutex_lock(&head->mutex);
2908                         kfree(head->extent_op);
2909                         delayed_refs->num_heads--;
2910                         if (list_empty(&head->cluster))
2911                                 delayed_refs->num_heads_ready--;
2912                         list_del_init(&head->cluster);
2913                         mutex_unlock(&head->mutex);
2914                 }
2915
2916                 spin_unlock(&delayed_refs->lock);
2917                 btrfs_put_delayed_ref(ref);
2918
2919                 cond_resched();
2920                 spin_lock(&delayed_refs->lock);
2921         }
2922
2923         spin_unlock(&delayed_refs->lock);
2924
2925         return ret;
2926 }
2927
2928 static int btrfs_destroy_pending_snapshots(struct btrfs_transaction *t)
2929 {
2930         struct btrfs_pending_snapshot *snapshot;
2931         struct list_head splice;
2932
2933         INIT_LIST_HEAD(&splice);
2934
2935         list_splice_init(&t->pending_snapshots, &splice);
2936
2937         while (!list_empty(&splice)) {
2938                 snapshot = list_entry(splice.next,
2939                                       struct btrfs_pending_snapshot,
2940                                       list);
2941
2942                 list_del_init(&snapshot->list);
2943
2944                 kfree(snapshot);
2945         }
2946
2947         return 0;
2948 }
2949
2950 static int btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
2951 {
2952         struct btrfs_inode *btrfs_inode;
2953         struct list_head splice;
2954
2955         INIT_LIST_HEAD(&splice);
2956
2957         list_splice_init(&root->fs_info->delalloc_inodes, &splice);
2958
2959         spin_lock(&root->fs_info->delalloc_lock);
2960
2961         while (!list_empty(&splice)) {
2962                 btrfs_inode = list_entry(splice.next, struct btrfs_inode,
2963                                     delalloc_inodes);
2964
2965                 list_del_init(&btrfs_inode->delalloc_inodes);
2966
2967                 btrfs_invalidate_inodes(btrfs_inode->root);
2968         }
2969
2970         spin_unlock(&root->fs_info->delalloc_lock);
2971
2972         return 0;
2973 }
2974
2975 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
2976                                         struct extent_io_tree *dirty_pages,
2977                                         int mark)
2978 {
2979         int ret;
2980         struct page *page;
2981         struct inode *btree_inode = root->fs_info->btree_inode;
2982         struct extent_buffer *eb;
2983         u64 start = 0;
2984         u64 end;
2985         u64 offset;
2986         unsigned long index;
2987
2988         while (1) {
2989                 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
2990                                             mark);
2991                 if (ret)
2992                         break;
2993
2994                 clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
2995                 while (start <= end) {
2996                         index = start >> PAGE_CACHE_SHIFT;
2997                         start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
2998                         page = find_get_page(btree_inode->i_mapping, index);
2999                         if (!page)
3000                                 continue;
3001                         offset = page_offset(page);
3002
3003                         spin_lock(&dirty_pages->buffer_lock);
3004                         eb = radix_tree_lookup(
3005                              &(&BTRFS_I(page->mapping->host)->io_tree)->buffer,
3006                                                offset >> PAGE_CACHE_SHIFT);
3007                         spin_unlock(&dirty_pages->buffer_lock);
3008                         if (eb) {
3009                                 ret = test_and_clear_bit(EXTENT_BUFFER_DIRTY,
3010                                                          &eb->bflags);
3011                                 atomic_set(&eb->refs, 1);
3012                         }
3013                         if (PageWriteback(page))
3014                                 end_page_writeback(page);
3015
3016                         lock_page(page);
3017                         if (PageDirty(page)) {
3018                                 clear_page_dirty_for_io(page);
3019                                 spin_lock_irq(&page->mapping->tree_lock);
3020                                 radix_tree_tag_clear(&page->mapping->page_tree,
3021                                                         page_index(page),
3022                                                         PAGECACHE_TAG_DIRTY);
3023                                 spin_unlock_irq(&page->mapping->tree_lock);
3024                         }
3025
3026                         page->mapping->a_ops->invalidatepage(page, 0);
3027                         unlock_page(page);
3028                 }
3029         }
3030
3031         return ret;
3032 }
3033
3034 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
3035                                        struct extent_io_tree *pinned_extents)
3036 {
3037         struct extent_io_tree *unpin;
3038         u64 start;
3039         u64 end;
3040         int ret;
3041
3042         unpin = pinned_extents;
3043         while (1) {
3044                 ret = find_first_extent_bit(unpin, 0, &start, &end,
3045                                             EXTENT_DIRTY);
3046                 if (ret)
3047                         break;
3048
3049                 /* opt_discard */
3050                 ret = btrfs_error_discard_extent(root, start, end + 1 - start);
3051
3052                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
3053                 btrfs_error_unpin_extent_range(root, start, end);
3054                 cond_resched();
3055         }
3056
3057         return 0;
3058 }
3059
3060 static int btrfs_cleanup_transaction(struct btrfs_root *root)
3061 {
3062         struct btrfs_transaction *t;
3063         LIST_HEAD(list);
3064
3065         WARN_ON(1);
3066
3067         mutex_lock(&root->fs_info->trans_mutex);
3068         mutex_lock(&root->fs_info->transaction_kthread_mutex);
3069
3070         list_splice_init(&root->fs_info->trans_list, &list);
3071         while (!list_empty(&list)) {
3072                 t = list_entry(list.next, struct btrfs_transaction, list);
3073                 if (!t)
3074                         break;
3075
3076                 btrfs_destroy_ordered_operations(root);
3077
3078                 btrfs_destroy_ordered_extents(root);
3079
3080                 btrfs_destroy_delayed_refs(t, root);
3081
3082                 btrfs_block_rsv_release(root,
3083                                         &root->fs_info->trans_block_rsv,
3084                                         t->dirty_pages.dirty_bytes);
3085
3086                 /* FIXME: cleanup wait for commit */
3087                 t->in_commit = 1;
3088                 t->blocked = 1;
3089                 if (waitqueue_active(&root->fs_info->transaction_blocked_wait))
3090                         wake_up(&root->fs_info->transaction_blocked_wait);
3091
3092                 t->blocked = 0;
3093                 if (waitqueue_active(&root->fs_info->transaction_wait))
3094                         wake_up(&root->fs_info->transaction_wait);
3095                 mutex_unlock(&root->fs_info->trans_mutex);
3096
3097                 mutex_lock(&root->fs_info->trans_mutex);
3098                 t->commit_done = 1;
3099                 if (waitqueue_active(&t->commit_wait))
3100                         wake_up(&t->commit_wait);
3101                 mutex_unlock(&root->fs_info->trans_mutex);
3102
3103                 mutex_lock(&root->fs_info->trans_mutex);
3104
3105                 btrfs_destroy_pending_snapshots(t);
3106
3107                 btrfs_destroy_delalloc_inodes(root);
3108
3109                 spin_lock(&root->fs_info->new_trans_lock);
3110                 root->fs_info->running_transaction = NULL;
3111                 spin_unlock(&root->fs_info->new_trans_lock);
3112
3113                 btrfs_destroy_marked_extents(root, &t->dirty_pages,
3114                                              EXTENT_DIRTY);
3115
3116                 btrfs_destroy_pinned_extent(root,
3117                                             root->fs_info->pinned_extents);
3118
3119                 t->use_count = 0;
3120                 list_del_init(&t->list);
3121                 memset(t, 0, sizeof(*t));
3122                 kmem_cache_free(btrfs_transaction_cachep, t);
3123         }
3124
3125         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
3126         mutex_unlock(&root->fs_info->trans_mutex);
3127
3128         return 0;
3129 }
3130
3131 static struct extent_io_ops btree_extent_io_ops = {
3132         .write_cache_pages_lock_hook = btree_lock_page_hook,
3133         .readpage_end_io_hook = btree_readpage_end_io_hook,
3134         .submit_bio_hook = btree_submit_bio_hook,
3135         /* note we're sharing with inode.c for the merge bio hook */
3136         .merge_bio_hook = btrfs_merge_bio_hook,
3137 };