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/slab.h>
  30 #include <linux/migrate.h>
  31 #include <linux/ratelimit.h>
  32 #include <linux/uuid.h>
  33 #include <linux/semaphore.h>
  34 #include <asm/unaligned.h>
  35 #include "ctree.h"
  36 #include "disk-io.h"
  37 #include "hash.h"
  38 #include "transaction.h"
  39 #include "btrfs_inode.h"
  40 #include "volumes.h"
  41 #include "print-tree.h"
  42 #include "locking.h"
  43 #include "tree-log.h"
  44 #include "free-space-cache.h"
  45 #include "inode-map.h"
  46 #include "check-integrity.h"
  47 #include "rcu-string.h"
  48 #include "dev-replace.h"
  49 #include "raid56.h"
  50 #include "sysfs.h"
  51 #include "qgroup.h"
  52
  53 #ifdef CONFIG_X86
  54 #include <asm/cpufeature.h>
  55 #endif
  56
  57 static struct extent_io_ops btree_extent_io_ops;
  58 static void end_workqueue_fn(struct btrfs_work *work);
  59 static void free_fs_root(struct btrfs_root *root);
  60 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
  61                                     int read_only);
  62 static void btrfs_destroy_ordered_extents(struct btrfs_root *root);
  63 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
  64                                       struct btrfs_root *root);
  65 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
  66 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
  67                                         struct extent_io_tree *dirty_pages,
  68                                         int mark);
  69 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
  70                                        struct extent_io_tree *pinned_extents);
  71 static int btrfs_cleanup_transaction(struct btrfs_root *root);
  72 static void btrfs_error_commit_super(struct btrfs_root *root);
  73
  74 /*
  75  * btrfs_end_io_wq structs are used to do processing in task context when an IO
  76  * is complete.  This is used during reads to verify checksums, and it is used
  77  * by writes to insert metadata for new file extents after IO is complete.
  78  */
  79 struct btrfs_end_io_wq {
  80         struct bio *bio;
  81         bio_end_io_t *end_io;
  82         void *private;
  83         struct btrfs_fs_info *info;
  84         int error;
  85         enum btrfs_wq_endio_type metadata;
  86         struct list_head list;
  87         struct btrfs_work work;
  88 };
  89
  90 static struct kmem_cache *btrfs_end_io_wq_cache;
  91
  92 int __init btrfs_end_io_wq_init(void)
  93 {
  94         btrfs_end_io_wq_cache = kmem_cache_create("btrfs_end_io_wq",
  95                                         sizeof(struct btrfs_end_io_wq),
  96                                         0,
  97                                         SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
  98                                         NULL);
  99         if (!btrfs_end_io_wq_cache)
 100                 return -ENOMEM;
 101         return 0;
 102 }
 103
 104 void btrfs_end_io_wq_exit(void)
 105 {
 106         if (btrfs_end_io_wq_cache)
 107                 kmem_cache_destroy(btrfs_end_io_wq_cache);
 108 }
 109
 110 /*
 111  * async submit bios are used to offload expensive checksumming
 112  * onto the worker threads.  They checksum file and metadata bios
 113  * just before they are sent down the IO stack.
 114  */
 115 struct async_submit_bio {
 116         struct inode *inode;
 117         struct bio *bio;
 118         struct list_head list;
 119         extent_submit_bio_hook_t *submit_bio_start;
 120         extent_submit_bio_hook_t *submit_bio_done;
 121         int rw;
 122         int mirror_num;
 123         unsigned long bio_flags;
 124         /*
 125          * bio_offset is optional, can be used if the pages in the bio
 126          * can't tell us where in the file the bio should go
 127          */
 128         u64 bio_offset;
 129         struct btrfs_work work;
 130         int error;
 131 };
 132
 133 /*
 134  * Lockdep class keys for extent_buffer->lock's in this root.  For a given
 135  * eb, the lockdep key is determined by the btrfs_root it belongs to and
 136  * the level the eb occupies in the tree.
 137  *
 138  * Different roots are used for different purposes and may nest inside each
 139  * other and they require separate keysets.  As lockdep keys should be
 140  * static, assign keysets according to the purpose of the root as indicated
 141  * by btrfs_root->objectid.  This ensures that all special purpose roots
 142  * have separate keysets.
 143  *
 144  * Lock-nesting across peer nodes is always done with the immediate parent
 145  * node locked thus preventing deadlock.  As lockdep doesn't know this, use
 146  * subclass to avoid triggering lockdep warning in such cases.
 147  *
 148  * The key is set by the readpage_end_io_hook after the buffer has passed
 149  * csum validation but before the pages are unlocked.  It is also set by
 150  * btrfs_init_new_buffer on freshly allocated blocks.
 151  *
 152  * We also add a check to make sure the highest level of the tree is the
 153  * same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this code
 154  * needs update as well.
 155  */
 156 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 157 # if BTRFS_MAX_LEVEL != 8
 158 #  error
 159 # endif
 160
 161 static struct btrfs_lockdep_keyset {
 162         u64                     id;             /* root objectid */
 163         const char              *name_stem;     /* lock name stem */
 164         char                    names[BTRFS_MAX_LEVEL + 1][20];
 165         struct lock_class_key   keys[BTRFS_MAX_LEVEL + 1];
 166 } btrfs_lockdep_keysets[] = {
 167         { .id = BTRFS_ROOT_TREE_OBJECTID,       .name_stem = "root"     },
 168         { .id = BTRFS_EXTENT_TREE_OBJECTID,     .name_stem = "extent"   },
 169         { .id = BTRFS_CHUNK_TREE_OBJECTID,      .name_stem = "chunk"    },
 170         { .id = BTRFS_DEV_TREE_OBJECTID,        .name_stem = "dev"      },
 171         { .id = BTRFS_FS_TREE_OBJECTID,         .name_stem = "fs"       },
 172         { .id = BTRFS_CSUM_TREE_OBJECTID,       .name_stem = "csum"     },
 173         { .id = BTRFS_QUOTA_TREE_OBJECTID,      .name_stem = "quota"    },
 174         { .id = BTRFS_TREE_LOG_OBJECTID,        .name_stem = "log"      },
 175         { .id = BTRFS_TREE_RELOC_OBJECTID,      .name_stem = "treloc"   },
 176         { .id = BTRFS_DATA_RELOC_TREE_OBJECTID, .name_stem = "dreloc"   },
 177         { .id = BTRFS_UUID_TREE_OBJECTID,       .name_stem = "uuid"     },
 178         { .id = 0,                              .name_stem = "tree"     },
 179 };
 180
 181 void __init btrfs_init_lockdep(void)
 182 {
 183         int i, j;
 184
 185         /* initialize lockdep class names */
 186         for (i = 0; i < ARRAY_SIZE(btrfs_lockdep_keysets); i++) {
 187                 struct btrfs_lockdep_keyset *ks = &btrfs_lockdep_keysets[i];
 188
 189                 for (j = 0; j < ARRAY_SIZE(ks->names); j++)
 190                         snprintf(ks->names[j], sizeof(ks->names[j]),
 191                                  "btrfs-%s-%02d", ks->name_stem, j);
 192         }
 193 }
 194
 195 void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb,
 196                                     int level)
 197 {
 198         struct btrfs_lockdep_keyset *ks;
 199
 200         BUG_ON(level >= ARRAY_SIZE(ks->keys));
 201
 202         /* find the matching keyset, id 0 is the default entry */
 203         for (ks = btrfs_lockdep_keysets; ks->id; ks++)
 204                 if (ks->id == objectid)
 205                         break;
 206
 207         lockdep_set_class_and_name(&eb->lock,
 208                                    &ks->keys[level], ks->names[level]);
 209 }
 210
 211 #endif
 212
 213 /*
 214  * extents on the btree inode are pretty simple, there's one extent
 215  * that covers the entire device
 216  */
 217 static struct extent_map *btree_get_extent(struct inode *inode,
 218                 struct page *page, size_t pg_offset, u64 start, u64 len,
 219                 int create)
 220 {
 221         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 222         struct extent_map *em;
 223         int ret;
 224
 225         read_lock(&em_tree->lock);
 226         em = lookup_extent_mapping(em_tree, start, len);
 227         if (em) {
 228                 em->bdev =
 229                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 230                 read_unlock(&em_tree->lock);
 231                 goto out;
 232         }
 233         read_unlock(&em_tree->lock);
 234
 235         em = alloc_extent_map();
 236         if (!em) {
 237                 em = ERR_PTR(-ENOMEM);
 238                 goto out;
 239         }
 240         em->start = 0;
 241         em->len = (u64)-1;
 242         em->block_len = (u64)-1;
 243         em->block_start = 0;
 244         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 245
 246         write_lock(&em_tree->lock);
 247         ret = add_extent_mapping(em_tree, em, 0);
 248         if (ret == -EEXIST) {
 249                 free_extent_map(em);
 250                 em = lookup_extent_mapping(em_tree, start, len);
 251                 if (!em)
 252                         em = ERR_PTR(-EIO);
 253         } else if (ret) {
 254                 free_extent_map(em);
 255                 em = ERR_PTR(ret);
 256         }
 257         write_unlock(&em_tree->lock);
 258
 259 out:
 260         return em;
 261 }
 262
 263 u32 btrfs_csum_data(char *data, u32 seed, size_t len)
 264 {
 265         return btrfs_crc32c(seed, data, len);
 266 }
 267
 268 void btrfs_csum_final(u32 crc, char *result)
 269 {
 270         put_unaligned_le32(~crc, result);
 271 }
 272
 273 /*
 274  * compute the csum for a btree block, and either verify it or write it
 275  * into the csum field of the block.
 276  */
 277 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 278                            int verify)
 279 {
 280         u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
 281         char *result = NULL;
 282         unsigned long len;
 283         unsigned long cur_len;
 284         unsigned long offset = BTRFS_CSUM_SIZE;
 285         char *kaddr;
 286         unsigned long map_start;
 287         unsigned long map_len;
 288         int err;
 289         u32 crc = ~(u32)0;
 290         unsigned long inline_result;
 291
 292         len = buf->len - offset;
 293         while (len > 0) {
 294                 err = map_private_extent_buffer(buf, offset, 32,
 295                                         &kaddr, &map_start, &map_len);
 296                 if (err)
 297                         return 1;
 298                 cur_len = min(len, map_len - (offset - map_start));
 299                 crc = btrfs_csum_data(kaddr + offset - map_start,
 300                                       crc, cur_len);
 301                 len -= cur_len;
 302                 offset += cur_len;
 303         }
 304         if (csum_size > sizeof(inline_result)) {
 305                 result = kzalloc(csum_size * sizeof(char), GFP_NOFS);
 306                 if (!result)
 307                         return 1;
 308         } else {
 309                 result = (char *)&inline_result;
 310         }
 311
 312         btrfs_csum_final(crc, result);
 313
 314         if (verify) {
 315                 if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
 316                         u32 val;
 317                         u32 found = 0;
 318                         memcpy(&found, result, csum_size);
 319
 320                         read_extent_buffer(buf, &val, 0, csum_size);
 321                         printk_ratelimited(KERN_INFO
 322                                 "BTRFS: %s checksum verify failed on %llu wanted %X found %X "
 323                                 "level %d\n",
 324                                 root->fs_info->sb->s_id, buf->start,
 325                                 val, found, btrfs_header_level(buf));
 326                         if (result != (char *)&inline_result)
 327                                 kfree(result);
 328                         return 1;
 329                 }
 330         } else {
 331                 write_extent_buffer(buf, result, 0, csum_size);
 332         }
 333         if (result != (char *)&inline_result)
 334                 kfree(result);
 335         return 0;
 336 }
 337
 338 /*
 339  * we can't consider a given block up to date unless the transid of the
 340  * block matches the transid in the parent node's pointer.  This is how we
 341  * detect blocks that either didn't get written at all or got written
 342  * in the wrong place.
 343  */
 344 static int verify_parent_transid(struct extent_io_tree *io_tree,
 345                                  struct extent_buffer *eb, u64 parent_transid,
 346                                  int atomic)
 347 {
 348         struct extent_state *cached_state = NULL;
 349         int ret;
 350         bool need_lock = (current->journal_info == BTRFS_SEND_TRANS_STUB);
 351
 352         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
 353                 return 0;
 354
 355         if (atomic)
 356                 return -EAGAIN;
 357
 358         if (need_lock) {
 359                 btrfs_tree_read_lock(eb);
 360                 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
 361         }
 362
 363         lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
 364                          0, &cached_state);
 365         if (extent_buffer_uptodate(eb) &&
 366             btrfs_header_generation(eb) == parent_transid) {
 367                 ret = 0;
 368                 goto out;
 369         }
 370         printk_ratelimited(KERN_INFO "BTRFS (device %s): parent transid verify failed on %llu wanted %llu found %llu\n",
 371                         eb->fs_info->sb->s_id, eb->start,
 372                         parent_transid, btrfs_header_generation(eb));
 373         ret = 1;
 374
 375         /*
 376          * Things reading via commit roots that don't have normal protection,
 377          * like send, can have a really old block in cache that may point at a
 378          * block that has been free'd and re-allocated.  So don't clear uptodate
 379          * if we find an eb that is under IO (dirty/writeback) because we could
 380          * end up reading in the stale data and then writing it back out and
 381          * making everybody very sad.
 382          */
 383         if (!extent_buffer_under_io(eb))
 384                 clear_extent_buffer_uptodate(eb);
 385 out:
 386         unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
 387                              &cached_state, GFP_NOFS);
 388         if (need_lock)
 389                 btrfs_tree_read_unlock_blocking(eb);
 390         return ret;
 391 }
 392
 393 /*
 394  * Return 0 if the superblock checksum type matches the checksum value of that
 395  * algorithm. Pass the raw disk superblock data.
 396  */
 397 static int btrfs_check_super_csum(char *raw_disk_sb)
 398 {
 399         struct btrfs_super_block *disk_sb =
 400                 (struct btrfs_super_block *)raw_disk_sb;
 401         u16 csum_type = btrfs_super_csum_type(disk_sb);
 402         int ret = 0;
 403
 404         if (csum_type == BTRFS_CSUM_TYPE_CRC32) {
 405                 u32 crc = ~(u32)0;
 406                 const int csum_size = sizeof(crc);
 407                 char result[csum_size];
 408
 409                 /*
 410                  * The super_block structure does not span the whole
 411                  * BTRFS_SUPER_INFO_SIZE range, we expect that the unused space
 412                  * is filled with zeros and is included in the checkum.
 413                  */
 414                 crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE,
 415                                 crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
 416                 btrfs_csum_final(crc, result);
 417
 418                 if (memcmp(raw_disk_sb, result, csum_size))
 419                         ret = 1;
 420
 421                 if (ret && btrfs_super_generation(disk_sb) < 10) {
 422                         printk(KERN_WARNING
 423                                 "BTRFS: super block crcs don't match, older mkfs detected\n");
 424                         ret = 0;
 425                 }
 426         }
 427
 428         if (csum_type >= ARRAY_SIZE(btrfs_csum_sizes)) {
 429                 printk(KERN_ERR "BTRFS: unsupported checksum algorithm %u\n",
 430                                 csum_type);
 431                 ret = 1;
 432         }
 433
 434         return ret;
 435 }
 436
 437 /*
 438  * helper to read a given tree block, doing retries as required when
 439  * the checksums don't match and we have alternate mirrors to try.
 440  */
 441 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
 442                                           struct extent_buffer *eb,
 443                                           u64 start, u64 parent_transid)
 444 {
 445         struct extent_io_tree *io_tree;
 446         int failed = 0;
 447         int ret;
 448         int num_copies = 0;
 449         int mirror_num = 0;
 450         int failed_mirror = 0;
 451
 452         clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
 453         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
 454         while (1) {
 455                 ret = read_extent_buffer_pages(io_tree, eb, start,
 456                                                WAIT_COMPLETE,
 457                                                btree_get_extent, mirror_num);
 458                 if (!ret) {
 459                         if (!verify_parent_transid(io_tree, eb,
 460                                                    parent_transid, 0))
 461                                 break;
 462                         else
 463                                 ret = -EIO;
 464                 }
 465
 466                 /*
 467                  * This buffer's crc is fine, but its contents are corrupted, so
 468                  * there is no reason to read the other copies, they won't be
 469                  * any less wrong.
 470                  */
 471                 if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags))
 472                         break;
 473
 474                 num_copies = btrfs_num_copies(root->fs_info,
 475                                               eb->start, eb->len);
 476                 if (num_copies == 1)
 477                         break;
 478
 479                 if (!failed_mirror) {
 480                         failed = 1;
 481                         failed_mirror = eb->read_mirror;
 482                 }
 483
 484                 mirror_num++;
 485                 if (mirror_num == failed_mirror)
 486                         mirror_num++;
 487
 488                 if (mirror_num > num_copies)
 489                         break;
 490         }
 491
 492         if (failed && !ret && failed_mirror)
 493                 repair_eb_io_failure(root, eb, failed_mirror);
 494
 495         return ret;
 496 }
 497
 498 /*
 499  * checksum a dirty tree block before IO.  This has extra checks to make sure
 500  * we only fill in the checksum field in the first page of a multi-page block
 501  */
 502
 503 static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 504 {
 505         u64 start = page_offset(page);
 506         u64 found_start;
 507         struct extent_buffer *eb;
 508
 509         eb = (struct extent_buffer *)page->private;
 510         if (page != eb->pages[0])
 511                 return 0;
 512         found_start = btrfs_header_bytenr(eb);
 513         if (WARN_ON(found_start != start || !PageUptodate(page)))
 514                 return 0;
 515         csum_tree_block(root, eb, 0);
 516         return 0;
 517 }
 518
 519 static int check_tree_block_fsid(struct btrfs_root *root,
 520                                  struct extent_buffer *eb)
 521 {
 522         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
 523         u8 fsid[BTRFS_UUID_SIZE];
 524         int ret = 1;
 525
 526         read_extent_buffer(eb, fsid, btrfs_header_fsid(), BTRFS_FSID_SIZE);
 527         while (fs_devices) {
 528                 if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
 529                         ret = 0;
 530                         break;
 531                 }
 532                 fs_devices = fs_devices->seed;
 533         }
 534         return ret;
 535 }
 536
 537 #define CORRUPT(reason, eb, root, slot)                         \
 538         btrfs_crit(root->fs_info, "corrupt leaf, %s: block=%llu,"       \
 539                    "root=%llu, slot=%d", reason,                        \
 540                btrfs_header_bytenr(eb), root->objectid, slot)
 541
 542 static noinline int check_leaf(struct btrfs_root *root,
 543                                struct extent_buffer *leaf)
 544 {
 545         struct btrfs_key key;
 546         struct btrfs_key leaf_key;
 547         u32 nritems = btrfs_header_nritems(leaf);
 548         int slot;
 549
 550         if (nritems == 0)
 551                 return 0;
 552
 553         /* Check the 0 item */
 554         if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
 555             BTRFS_LEAF_DATA_SIZE(root)) {
 556                 CORRUPT("invalid item offset size pair", leaf, root, 0);
 557                 return -EIO;
 558         }
 559
 560         /*
 561          * Check to make sure each items keys are in the correct order and their
 562          * offsets make sense.  We only have to loop through nritems-1 because
 563          * we check the current slot against the next slot, which verifies the
 564          * next slot's offset+size makes sense and that the current's slot
 565          * offset is correct.
 566          */
 567         for (slot = 0; slot < nritems - 1; slot++) {
 568                 btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
 569                 btrfs_item_key_to_cpu(leaf, &key, slot + 1);
 570
 571                 /* Make sure the keys are in the right order */
 572                 if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
 573                         CORRUPT("bad key order", leaf, root, slot);
 574                         return -EIO;
 575                 }
 576
 577                 /*
 578                  * Make sure the offset and ends are right, remember that the
 579                  * item data starts at the end of the leaf and grows towards the
 580                  * front.
 581                  */
 582                 if (btrfs_item_offset_nr(leaf, slot) !=
 583                         btrfs_item_end_nr(leaf, slot + 1)) {
 584                         CORRUPT("slot offset bad", leaf, root, slot);
 585                         return -EIO;
 586                 }
 587
 588                 /*
 589                  * Check to make sure that we don't point outside of the leaf,
 590                  * just incase all the items are consistent to eachother, but
 591                  * all point outside of the leaf.
 592                  */
 593                 if (btrfs_item_end_nr(leaf, slot) >
 594                     BTRFS_LEAF_DATA_SIZE(root)) {
 595                         CORRUPT("slot end outside of leaf", leaf, root, slot);
 596                         return -EIO;
 597                 }
 598         }
 599
 600         return 0;
 601 }
 602
 603 static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
 604                                       u64 phy_offset, struct page *page,
 605                                       u64 start, u64 end, int mirror)
 606 {
 607         u64 found_start;
 608         int found_level;
 609         struct extent_buffer *eb;
 610         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 611         int ret = 0;
 612         int reads_done;
 613
 614         if (!page->private)
 615                 goto out;
 616
 617         eb = (struct extent_buffer *)page->private;
 618
 619         /* the pending IO might have been the only thing that kept this buffer
 620          * in memory.  Make sure we have a ref for all this other checks
 621          */
 622         extent_buffer_get(eb);
 623
 624         reads_done = atomic_dec_and_test(&eb->io_pages);
 625         if (!reads_done)
 626                 goto err;
 627
 628         eb->read_mirror = mirror;
 629         if (test_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags)) {
 630                 ret = -EIO;
 631                 goto err;
 632         }
 633
 634         found_start = btrfs_header_bytenr(eb);
 635         if (found_start != eb->start) {
 636                 printk_ratelimited(KERN_INFO "BTRFS (device %s): bad tree block start "
 637                                "%llu %llu\n",
 638                                eb->fs_info->sb->s_id, found_start, eb->start);
 639                 ret = -EIO;
 640                 goto err;
 641         }
 642         if (check_tree_block_fsid(root, eb)) {
 643                 printk_ratelimited(KERN_INFO "BTRFS (device %s): bad fsid on block %llu\n",
 644                                eb->fs_info->sb->s_id, eb->start);
 645                 ret = -EIO;
 646                 goto err;
 647         }
 648         found_level = btrfs_header_level(eb);
 649         if (found_level >= BTRFS_MAX_LEVEL) {
 650                 btrfs_info(root->fs_info, "bad tree block level %d",
 651                            (int)btrfs_header_level(eb));
 652                 ret = -EIO;
 653                 goto err;
 654         }
 655
 656         btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb),
 657                                        eb, found_level);
 658
 659         ret = csum_tree_block(root, eb, 1);
 660         if (ret) {
 661                 ret = -EIO;
 662                 goto err;
 663         }
 664
 665         /*
 666          * If this is a leaf block and it is corrupt, set the corrupt bit so
 667          * that we don't try and read the other copies of this block, just
 668          * return -EIO.
 669          */
 670         if (found_level == 0 && check_leaf(root, eb)) {
 671                 set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
 672                 ret = -EIO;
 673         }
 674
 675         if (!ret)
 676                 set_extent_buffer_uptodate(eb);
 677 err:
 678         if (reads_done &&
 679             test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
 680                 btree_readahead_hook(root, eb, eb->start, ret);
 681
 682         if (ret) {
 683                 /*
 684                  * our io error hook is going to dec the io pages
 685                  * again, we have to make sure it has something
 686                  * to decrement
 687                  */
 688                 atomic_inc(&eb->io_pages);
 689                 clear_extent_buffer_uptodate(eb);
 690         }
 691         free_extent_buffer(eb);
 692 out:
 693         return ret;
 694 }
 695
 696 static int btree_io_failed_hook(struct page *page, int failed_mirror)
 697 {
 698         struct extent_buffer *eb;
 699         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 700
 701         eb = (struct extent_buffer *)page->private;
 702         set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
 703         eb->read_mirror = failed_mirror;
 704         atomic_dec(&eb->io_pages);
 705         if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
 706                 btree_readahead_hook(root, eb, eb->start, -EIO);
 707         return -EIO;    /* we fixed nothing */
 708 }
 709
 710 static void end_workqueue_bio(struct bio *bio, int err)
 711 {
 712         struct btrfs_end_io_wq *end_io_wq = bio->bi_private;
 713         struct btrfs_fs_info *fs_info;
 714         struct btrfs_workqueue *wq;
 715         btrfs_work_func_t func;
 716
 717         fs_info = end_io_wq->info;
 718         end_io_wq->error = err;
 719
 720         if (bio->bi_rw & REQ_WRITE) {
 721                 if (end_io_wq->metadata == BTRFS_WQ_ENDIO_METADATA) {
 722                         wq = fs_info->endio_meta_write_workers;
 723                         func = btrfs_endio_meta_write_helper;
 724                 } else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_FREE_SPACE) {
 725                         wq = fs_info->endio_freespace_worker;
 726                         func = btrfs_freespace_write_helper;
 727                 } else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56) {
 728                         wq = fs_info->endio_raid56_workers;
 729                         func = btrfs_endio_raid56_helper;
 730                 } else {
 731                         wq = fs_info->endio_write_workers;
 732                         func = btrfs_endio_write_helper;
 733                 }
 734         } else {
 735                 if (unlikely(end_io_wq->metadata ==
 736                              BTRFS_WQ_ENDIO_DIO_REPAIR)) {
 737                         wq = fs_info->endio_repair_workers;
 738                         func = btrfs_endio_repair_helper;
 739                 } else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56) {
 740                         wq = fs_info->endio_raid56_workers;
 741                         func = btrfs_endio_raid56_helper;
 742                 } else if (end_io_wq->metadata) {
 743                         wq = fs_info->endio_meta_workers;
 744                         func = btrfs_endio_meta_helper;
 745                 } else {
 746                         wq = fs_info->endio_workers;
 747                         func = btrfs_endio_helper;
 748                 }
 749         }
 750
 751         btrfs_init_work(&end_io_wq->work, func, end_workqueue_fn, NULL, NULL);
 752         btrfs_queue_work(wq, &end_io_wq->work);
 753 }
 754
 755 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 756                         enum btrfs_wq_endio_type metadata)
 757 {
 758         struct btrfs_end_io_wq *end_io_wq;
 759
 760         end_io_wq = kmem_cache_alloc(btrfs_end_io_wq_cache, GFP_NOFS);
 761         if (!end_io_wq)
 762                 return -ENOMEM;
 763
 764         end_io_wq->private = bio->bi_private;
 765         end_io_wq->end_io = bio->bi_end_io;
 766         end_io_wq->info = info;
 767         end_io_wq->error = 0;
 768         end_io_wq->bio = bio;
 769         end_io_wq->metadata = metadata;
 770
 771         bio->bi_private = end_io_wq;
 772         bio->bi_end_io = end_workqueue_bio;
 773         return 0;
 774 }
 775
 776 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
 777 {
 778         unsigned long limit = min_t(unsigned long,
 779                                     info->thread_pool_size,
 780                                     info->fs_devices->open_devices);
 781         return 256 * limit;
 782 }
 783
 784 static void run_one_async_start(struct btrfs_work *work)
 785 {
 786         struct async_submit_bio *async;
 787         int ret;
 788
 789         async = container_of(work, struct  async_submit_bio, work);
 790         ret = async->submit_bio_start(async->inode, async->rw, async->bio,
 791                                       async->mirror_num, async->bio_flags,
 792                                       async->bio_offset);
 793         if (ret)
 794                 async->error = ret;
 795 }
 796
 797 static void run_one_async_done(struct btrfs_work *work)
 798 {
 799         struct btrfs_fs_info *fs_info;
 800         struct async_submit_bio *async;
 801         int limit;
 802
 803         async = container_of(work, struct  async_submit_bio, work);
 804         fs_info = BTRFS_I(async->inode)->root->fs_info;
 805
 806         limit = btrfs_async_submit_limit(fs_info);
 807         limit = limit * 2 / 3;
 808
 809         if (atomic_dec_return(&fs_info->nr_async_submits) < limit &&
 810             waitqueue_active(&fs_info->async_submit_wait))
 811                 wake_up(&fs_info->async_submit_wait);
 812
 813         /* If an error occured we just want to clean up the bio and move on */
 814         if (async->error) {
 815                 bio_endio(async->bio, async->error);
 816                 return;
 817         }
 818
 819         async->submit_bio_done(async->inode, async->rw, async->bio,
 820                                async->mirror_num, async->bio_flags,
 821                                async->bio_offset);
 822 }
 823
 824 static void run_one_async_free(struct btrfs_work *work)
 825 {
 826         struct async_submit_bio *async;
 827
 828         async = container_of(work, struct  async_submit_bio, work);
 829         kfree(async);
 830 }
 831
 832 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 833                         int rw, struct bio *bio, int mirror_num,
 834                         unsigned long bio_flags,
 835                         u64 bio_offset,
 836                         extent_submit_bio_hook_t *submit_bio_start,
 837                         extent_submit_bio_hook_t *submit_bio_done)
 838 {
 839         struct async_submit_bio *async;
 840
 841         async = kmalloc(sizeof(*async), GFP_NOFS);
 842         if (!async)
 843                 return -ENOMEM;
 844
 845         async->inode = inode;
 846         async->rw = rw;
 847         async->bio = bio;
 848         async->mirror_num = mirror_num;
 849         async->submit_bio_start = submit_bio_start;
 850         async->submit_bio_done = submit_bio_done;
 851
 852         btrfs_init_work(&async->work, btrfs_worker_helper, run_one_async_start,
 853                         run_one_async_done, run_one_async_free);
 854
 855         async->bio_flags = bio_flags;
 856         async->bio_offset = bio_offset;
 857
 858         async->error = 0;
 859
 860         atomic_inc(&fs_info->nr_async_submits);
 861
 862         if (rw & REQ_SYNC)
 863                 btrfs_set_work_high_priority(&async->work);
 864
 865         btrfs_queue_work(fs_info->workers, &async->work);
 866
 867         while (atomic_read(&fs_info->async_submit_draining) &&
 868               atomic_read(&fs_info->nr_async_submits)) {
 869                 wait_event(fs_info->async_submit_wait,
 870                            (atomic_read(&fs_info->nr_async_submits) == 0));
 871         }
 872
 873         return 0;
 874 }
 875
 876 static int btree_csum_one_bio(struct bio *bio)
 877 {
 878         struct bio_vec *bvec;
 879         struct btrfs_root *root;
 880         int i, ret = 0;
 881
 882         bio_for_each_segment_all(bvec, bio, i) {
 883                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
 884                 ret = csum_dirty_buffer(root, bvec->bv_page);
 885                 if (ret)
 886                         break;
 887         }
 888
 889         return ret;
 890 }
 891
 892 static int __btree_submit_bio_start(struct inode *inode, int rw,
 893                                     struct bio *bio, int mirror_num,
 894                                     unsigned long bio_flags,
 895                                     u64 bio_offset)
 896 {
 897         /*
 898          * when we're called for a write, we're already in the async
 899          * submission context.  Just jump into btrfs_map_bio
 900          */
 901         return btree_csum_one_bio(bio);
 902 }
 903
 904 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
 905                                  int mirror_num, unsigned long bio_flags,
 906                                  u64 bio_offset)
 907 {
 908         int ret;
 909
 910         /*
 911          * when we're called for a write, we're already in the async
 912          * submission context.  Just jump into btrfs_map_bio
 913          */
 914         ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
 915         if (ret)
 916                 bio_endio(bio, ret);
 917         return ret;
 918 }
 919
 920 static int check_async_write(struct inode *inode, unsigned long bio_flags)
 921 {
 922         if (bio_flags & EXTENT_BIO_TREE_LOG)
 923                 return 0;
 924 #ifdef CONFIG_X86
 925         if (cpu_has_xmm4_2)
 926                 return 0;
 927 #endif
 928         return 1;
 929 }
 930
 931 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 932                                  int mirror_num, unsigned long bio_flags,
 933                                  u64 bio_offset)
 934 {
 935         int async = check_async_write(inode, bio_flags);
 936         int ret;
 937
 938         if (!(rw & REQ_WRITE)) {
 939                 /*
 940                  * called for a read, do the setup so that checksum validation
 941                  * can happen in the async kernel threads
 942                  */
 943                 ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
 944                                           bio, BTRFS_WQ_ENDIO_METADATA);
 945                 if (ret)
 946                         goto out_w_error;
 947                 ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 948                                     mirror_num, 0);
 949         } else if (!async) {
 950                 ret = btree_csum_one_bio(bio);
 951                 if (ret)
 952                         goto out_w_error;
 953                 ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 954                                     mirror_num, 0);
 955         } else {
 956                 /*
 957                  * kthread helpers are used to submit writes so that
 958                  * checksumming can happen in parallel across all CPUs
 959                  */
 960                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
 961                                           inode, rw, bio, mirror_num, 0,
 962                                           bio_offset,
 963                                           __btree_submit_bio_start,
 964                                           __btree_submit_bio_done);
 965         }
 966
 967         if (ret) {
 968 out_w_error:
 969                 bio_endio(bio, ret);
 970         }
 971         return ret;
 972 }
 973
 974 #ifdef CONFIG_MIGRATION
 975 static int btree_migratepage(struct address_space *mapping,
 976                         struct page *newpage, struct page *page,
 977                         enum migrate_mode mode)
 978 {
 979         /*
 980          * we can't safely write a btree page from here,
 981          * we haven't done the locking hook
 982          */
 983         if (PageDirty(page))
 984                 return -EAGAIN;
 985         /*
 986          * Buffers may be managed in a filesystem specific way.
 987          * We must have no buffers or drop them.
 988          */
 989         if (page_has_private(page) &&
 990             !try_to_release_page(page, GFP_KERNEL))
 991                 return -EAGAIN;
 992         return migrate_page(mapping, newpage, page, mode);
 993 }
 994 #endif
 995
 996
 997 static int btree_writepages(struct address_space *mapping,
 998                             struct writeback_control *wbc)
 999 {
1000         struct btrfs_fs_info *fs_info;
1001         int ret;
1002
1003         if (wbc->sync_mode == WB_SYNC_NONE) {
1004
1005                 if (wbc->for_kupdate)
1006                         return 0;
1007
1008                 fs_info = BTRFS_I(mapping->host)->root->fs_info;
1009                 /* this is a bit racy, but that's ok */
1010                 ret = percpu_counter_compare(&fs_info->dirty_metadata_bytes,
1011                                              BTRFS_DIRTY_METADATA_THRESH);
1012                 if (ret < 0)
1013                         return 0;
1014         }
1015         return btree_write_cache_pages(mapping, wbc);
1016 }
1017
1018 static int btree_readpage(struct file *file, struct page *page)
1019 {
1020         struct extent_io_tree *tree;
1021         tree = &BTRFS_I(page->mapping->host)->io_tree;
1022         return extent_read_full_page(tree, page, btree_get_extent, 0);
1023 }
1024
1025 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
1026 {
1027         if (PageWriteback(page) || PageDirty(page))
1028                 return 0;
1029
1030         return try_release_extent_buffer(page);
1031 }
1032
1033 static void btree_invalidatepage(struct page *page, unsigned int offset,
1034                                  unsigned int length)
1035 {
1036         struct extent_io_tree *tree;
1037         tree = &BTRFS_I(page->mapping->host)->io_tree;
1038         extent_invalidatepage(tree, page, offset);
1039         btree_releasepage(page, GFP_NOFS);
1040         if (PagePrivate(page)) {
1041                 btrfs_warn(BTRFS_I(page->mapping->host)->root->fs_info,
1042                            "page private not zero on page %llu",
1043                            (unsigned long long)page_offset(page));
1044                 ClearPagePrivate(page);
1045                 set_page_private(page, 0);
1046                 page_cache_release(page);
1047         }
1048 }
1049
1050 static int btree_set_page_dirty(struct page *page)
1051 {
1052 #ifdef DEBUG
1053         struct extent_buffer *eb;
1054
1055         BUG_ON(!PagePrivate(page));
1056         eb = (struct extent_buffer *)page->private;
1057         BUG_ON(!eb);
1058         BUG_ON(!test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
1059         BUG_ON(!atomic_read(&eb->refs));
1060         btrfs_assert_tree_locked(eb);
1061 #endif
1062         return __set_page_dirty_nobuffers(page);
1063 }
1064
1065 static const struct address_space_operations btree_aops = {
1066         .readpage       = btree_readpage,
1067         .writepages     = btree_writepages,
1068         .releasepage    = btree_releasepage,
1069         .invalidatepage = btree_invalidatepage,
1070 #ifdef CONFIG_MIGRATION
1071         .migratepage    = btree_migratepage,
1072 #endif
1073         .set_page_dirty = btree_set_page_dirty,
1074 };
1075
1076 void readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize)
1077 {
1078         struct extent_buffer *buf = NULL;
1079         struct inode *btree_inode = root->fs_info->btree_inode;
1080
1081         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1082         if (!buf)
1083                 return;
1084         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
1085                                  buf, 0, WAIT_NONE, btree_get_extent, 0);
1086         free_extent_buffer(buf);
1087 }
1088
1089 int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,
1090                          int mirror_num, struct extent_buffer **eb)
1091 {
1092         struct extent_buffer *buf = NULL;
1093         struct inode *btree_inode = root->fs_info->btree_inode;
1094         struct extent_io_tree *io_tree = &BTRFS_I(btree_inode)->io_tree;
1095         int ret;
1096
1097         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1098         if (!buf)
1099                 return 0;
1100
1101         set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
1102
1103         ret = read_extent_buffer_pages(io_tree, buf, 0, WAIT_PAGE_LOCK,
1104                                        btree_get_extent, mirror_num);
1105         if (ret) {
1106                 free_extent_buffer(buf);
1107                 return ret;
1108         }
1109
1110         if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
1111                 free_extent_buffer(buf);
1112                 return -EIO;
1113         } else if (extent_buffer_uptodate(buf)) {
1114                 *eb = buf;
1115         } else {
1116                 free_extent_buffer(buf);
1117         }
1118         return 0;
1119 }
1120
1121 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
1122                                             u64 bytenr)
1123 {
1124         return find_extent_buffer(root->fs_info, bytenr);
1125 }
1126
1127 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
1128                                                  u64 bytenr, u32 blocksize)
1129 {
1130         if (btrfs_test_is_dummy_root(root))
1131                 return alloc_test_extent_buffer(root->fs_info, bytenr,
1132                                                 blocksize);
1133         return alloc_extent_buffer(root->fs_info, bytenr, blocksize);
1134 }
1135
1136
1137 int btrfs_write_tree_block(struct extent_buffer *buf)
1138 {
1139         return filemap_fdatawrite_range(buf->pages[0]->mapping, buf->start,
1140                                         buf->start + buf->len - 1);
1141 }
1142
1143 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
1144 {
1145         return filemap_fdatawait_range(buf->pages[0]->mapping,
1146                                        buf->start, buf->start + buf->len - 1);
1147 }
1148
1149 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
1150                                       u64 parent_transid)
1151 {
1152         struct extent_buffer *buf = NULL;
1153         int ret;
1154
1155         buf = btrfs_find_create_tree_block(root, bytenr, root->nodesize);
1156         if (!buf)
1157                 return NULL;
1158
1159         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1160         if (ret) {
1161                 free_extent_buffer(buf);
1162                 return NULL;
1163         }
1164         return buf;
1165
1166 }
1167
1168 void clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1169                       struct extent_buffer *buf)
1170 {
1171         struct btrfs_fs_info *fs_info = root->fs_info;
1172
1173         if (btrfs_header_generation(buf) ==
1174             fs_info->running_transaction->transid) {
1175                 btrfs_assert_tree_locked(buf);
1176
1177                 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
1178                         __percpu_counter_add(&fs_info->dirty_metadata_bytes,
1179                                              -buf->len,
1180                                              fs_info->dirty_metadata_batch);
1181                         /* ugh, clear_extent_buffer_dirty needs to lock the page */
1182                         btrfs_set_lock_blocking(buf);
1183                         clear_extent_buffer_dirty(buf);
1184                 }
1185         }
1186 }
1187
1188 static struct btrfs_subvolume_writers *btrfs_alloc_subvolume_writers(void)
1189 {
1190         struct btrfs_subvolume_writers *writers;
1191         int ret;
1192
1193         writers = kmalloc(sizeof(*writers), GFP_NOFS);
1194         if (!writers)
1195                 return ERR_PTR(-ENOMEM);
1196
1197         ret = percpu_counter_init(&writers->counter, 0, GFP_KERNEL);
1198         if (ret < 0) {
1199                 kfree(writers);
1200                 return ERR_PTR(ret);
1201         }
1202
1203         init_waitqueue_head(&writers->wait);
1204         return writers;
1205 }
1206
1207 static void
1208 btrfs_free_subvolume_writers(struct btrfs_subvolume_writers *writers)
1209 {
1210         percpu_counter_destroy(&writers->counter);
1211         kfree(writers);
1212 }
1213
1214 static void __setup_root(u32 nodesize, u32 sectorsize, u32 stripesize,
1215                          struct btrfs_root *root, struct btrfs_fs_info *fs_info,
1216                          u64 objectid)
1217 {
1218         root->node = NULL;
1219         root->commit_root = NULL;
1220         root->sectorsize = sectorsize;
1221         root->nodesize = nodesize;
1222         root->stripesize = stripesize;
1223         root->state = 0;
1224         root->orphan_cleanup_state = 0;
1225
1226         root->objectid = objectid;
1227         root->last_trans = 0;
1228         root->highest_objectid = 0;
1229         root->nr_delalloc_inodes = 0;
1230         root->nr_ordered_extents = 0;
1231         root->name = NULL;
1232         root->inode_tree = RB_ROOT;
1233         INIT_RADIX_TREE(&root->delayed_nodes_tree, GFP_ATOMIC);
1234         root->block_rsv = NULL;
1235         root->orphan_block_rsv = NULL;
1236
1237         INIT_LIST_HEAD(&root->dirty_list);
1238         INIT_LIST_HEAD(&root->root_list);
1239         INIT_LIST_HEAD(&root->delalloc_inodes);
1240         INIT_LIST_HEAD(&root->delalloc_root);
1241         INIT_LIST_HEAD(&root->ordered_extents);
1242         INIT_LIST_HEAD(&root->ordered_root);
1243         INIT_LIST_HEAD(&root->logged_list[0]);
1244         INIT_LIST_HEAD(&root->logged_list[1]);
1245         spin_lock_init(&root->orphan_lock);
1246         spin_lock_init(&root->inode_lock);
1247         spin_lock_init(&root->delalloc_lock);
1248         spin_lock_init(&root->ordered_extent_lock);
1249         spin_lock_init(&root->accounting_lock);
1250         spin_lock_init(&root->log_extents_lock[0]);
1251         spin_lock_init(&root->log_extents_lock[1]);
1252         mutex_init(&root->objectid_mutex);
1253         mutex_init(&root->log_mutex);
1254         mutex_init(&root->ordered_extent_mutex);
1255         mutex_init(&root->delalloc_mutex);
1256         init_waitqueue_head(&root->log_writer_wait);
1257         init_waitqueue_head(&root->log_commit_wait[0]);
1258         init_waitqueue_head(&root->log_commit_wait[1]);
1259         INIT_LIST_HEAD(&root->log_ctxs[0]);
1260         INIT_LIST_HEAD(&root->log_ctxs[1]);
1261         atomic_set(&root->log_commit[0], 0);
1262         atomic_set(&root->log_commit[1], 0);
1263         atomic_set(&root->log_writers, 0);
1264         atomic_set(&root->log_batch, 0);
1265         atomic_set(&root->orphan_inodes, 0);
1266         atomic_set(&root->refs, 1);
1267         atomic_set(&root->will_be_snapshoted, 0);
1268         root->log_transid = 0;
1269         root->log_transid_committed = -1;
1270         root->last_log_commit = 0;
1271         if (fs_info)
1272                 extent_io_tree_init(&root->dirty_log_pages,
1273                                      fs_info->btree_inode->i_mapping);
1274
1275         memset(&root->root_key, 0, sizeof(root->root_key));
1276         memset(&root->root_item, 0, sizeof(root->root_item));
1277         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
1278         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
1279         if (fs_info)
1280                 root->defrag_trans_start = fs_info->generation;
1281         else
1282                 root->defrag_trans_start = 0;
1283         init_completion(&root->kobj_unregister);
1284         root->root_key.objectid = objectid;
1285         root->anon_dev = 0;
1286
1287         spin_lock_init(&root->root_item_lock);
1288 }
1289
1290 static struct btrfs_root *btrfs_alloc_root(struct btrfs_fs_info *fs_info)
1291 {
1292         struct btrfs_root *root = kzalloc(sizeof(*root), GFP_NOFS);
1293         if (root)
1294                 root->fs_info = fs_info;
1295         return root;
1296 }
1297
1298 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
1299 /* Should only be used by the testing infrastructure */
1300 struct btrfs_root *btrfs_alloc_dummy_root(void)
1301 {
1302         struct btrfs_root *root;
1303
1304         root = btrfs_alloc_root(NULL);
1305         if (!root)
1306                 return ERR_PTR(-ENOMEM);
1307         __setup_root(4096, 4096, 4096, root, NULL, 1);
1308         set_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state);
1309         root->alloc_bytenr = 0;
1310
1311         return root;
1312 }
1313 #endif
1314
1315 struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
1316                                      struct btrfs_fs_info *fs_info,
1317                                      u64 objectid)
1318 {
1319         struct extent_buffer *leaf;
1320         struct btrfs_root *tree_root = fs_info->tree_root;
1321         struct btrfs_root *root;
1322         struct btrfs_key key;
1323         int ret = 0;
1324         uuid_le uuid;
1325
1326         root = btrfs_alloc_root(fs_info);
1327         if (!root)
1328                 return ERR_PTR(-ENOMEM);
1329
1330         __setup_root(tree_root->nodesize, tree_root->sectorsize,
1331                 tree_root->stripesize, root, fs_info, objectid);
1332         root->root_key.objectid = objectid;
1333         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1334         root->root_key.offset = 0;
1335
1336         leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);
1337         if (IS_ERR(leaf)) {
1338                 ret = PTR_ERR(leaf);
1339                 leaf = NULL;
1340                 goto fail;
1341         }
1342
1343         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1344         btrfs_set_header_bytenr(leaf, leaf->start);
1345         btrfs_set_header_generation(leaf, trans->transid);
1346         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1347         btrfs_set_header_owner(leaf, objectid);
1348         root->node = leaf;
1349
1350         write_extent_buffer(leaf, fs_info->fsid, btrfs_header_fsid(),
1351                             BTRFS_FSID_SIZE);
1352         write_extent_buffer(leaf, fs_info->chunk_tree_uuid,
1353                             btrfs_header_chunk_tree_uuid(leaf),
1354                             BTRFS_UUID_SIZE);
1355         btrfs_mark_buffer_dirty(leaf);
1356
1357         root->commit_root = btrfs_root_node(root);
1358         set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
1359
1360         root->root_item.flags = 0;
1361         root->root_item.byte_limit = 0;
1362         btrfs_set_root_bytenr(&root->root_item, leaf->start);
1363         btrfs_set_root_generation(&root->root_item, trans->transid);
1364         btrfs_set_root_level(&root->root_item, 0);
1365         btrfs_set_root_refs(&root->root_item, 1);
1366         btrfs_set_root_used(&root->root_item, leaf->len);
1367         btrfs_set_root_last_snapshot(&root->root_item, 0);
1368         btrfs_set_root_dirid(&root->root_item, 0);
1369         uuid_le_gen(&uuid);
1370         memcpy(root->root_item.uuid, uuid.b, BTRFS_UUID_SIZE);
1371         root->root_item.drop_level = 0;
1372
1373         key.objectid = objectid;
1374         key.type = BTRFS_ROOT_ITEM_KEY;
1375         key.offset = 0;
1376         ret = btrfs_insert_root(trans, tree_root, &key, &root->root_item);
1377         if (ret)
1378                 goto fail;
1379
1380         btrfs_tree_unlock(leaf);
1381
1382         return root;
1383
1384 fail:
1385         if (leaf) {
1386                 btrfs_tree_unlock(leaf);
1387                 free_extent_buffer(root->commit_root);
1388                 free_extent_buffer(leaf);
1389         }
1390         kfree(root);
1391
1392         return ERR_PTR(ret);
1393 }
1394
1395 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1396                                          struct btrfs_fs_info *fs_info)
1397 {
1398         struct btrfs_root *root;
1399         struct btrfs_root *tree_root = fs_info->tree_root;
1400         struct extent_buffer *leaf;
1401
1402         root = btrfs_alloc_root(fs_info);
1403         if (!root)
1404                 return ERR_PTR(-ENOMEM);
1405
1406         __setup_root(tree_root->nodesize, tree_root->sectorsize,
1407                      tree_root->stripesize, root, fs_info,
1408                      BTRFS_TREE_LOG_OBJECTID);
1409
1410         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1411         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1412         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1413
1414         /*
1415          * DON'T set REF_COWS for log trees
1416          *
1417          * log trees do not get reference counted because they go away
1418          * before a real commit is actually done.  They do store pointers
1419          * to file data extents, and those reference counts still get
1420          * updated (along with back refs to the log tree).
1421          */
1422
1423         leaf = btrfs_alloc_tree_block(trans, root, 0, BTRFS_TREE_LOG_OBJECTID,
1424                         NULL, 0, 0, 0);
1425         if (IS_ERR(leaf)) {
1426                 kfree(root);
1427                 return ERR_CAST(leaf);
1428         }
1429
1430         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1431         btrfs_set_header_bytenr(leaf, leaf->start);
1432         btrfs_set_header_generation(leaf, trans->transid);
1433         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1434         btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1435         root->node = leaf;
1436
1437         write_extent_buffer(root->node, root->fs_info->fsid,
1438                             btrfs_header_fsid(), BTRFS_FSID_SIZE);
1439         btrfs_mark_buffer_dirty(root->node);
1440         btrfs_tree_unlock(root->node);
1441         return root;
1442 }
1443
1444 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1445                              struct btrfs_fs_info *fs_info)
1446 {
1447         struct btrfs_root *log_root;
1448
1449         log_root = alloc_log_tree(trans, fs_info);
1450         if (IS_ERR(log_root))
1451                 return PTR_ERR(log_root);
1452         WARN_ON(fs_info->log_root_tree);
1453         fs_info->log_root_tree = log_root;
1454         return 0;
1455 }
1456
1457 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1458                        struct btrfs_root *root)
1459 {
1460         struct btrfs_root *log_root;
1461         struct btrfs_inode_item *inode_item;
1462
1463         log_root = alloc_log_tree(trans, root->fs_info);
1464         if (IS_ERR(log_root))
1465                 return PTR_ERR(log_root);
1466
1467         log_root->last_trans = trans->transid;
1468         log_root->root_key.offset = root->root_key.objectid;
1469
1470         inode_item = &log_root->root_item.inode;
1471         btrfs_set_stack_inode_generation(inode_item, 1);
1472         btrfs_set_stack_inode_size(inode_item, 3);
1473         btrfs_set_stack_inode_nlink(inode_item, 1);
1474         btrfs_set_stack_inode_nbytes(inode_item, root->nodesize);
1475         btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
1476
1477         btrfs_set_root_node(&log_root->root_item, log_root->node);
1478
1479         WARN_ON(root->log_root);
1480         root->log_root = log_root;
1481         root->log_transid = 0;
1482         root->log_transid_committed = -1;
1483         root->last_log_commit = 0;
1484         return 0;
1485 }
1486
1487 static struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
1488                                                struct btrfs_key *key)
1489 {
1490         struct btrfs_root *root;
1491         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1492         struct btrfs_path *path;
1493         u64 generation;
1494         int ret;
1495
1496         path = btrfs_alloc_path();
1497         if (!path)
1498                 return ERR_PTR(-ENOMEM);
1499
1500         root = btrfs_alloc_root(fs_info);
1501         if (!root) {
1502                 ret = -ENOMEM;
1503                 goto alloc_fail;
1504         }
1505
1506         __setup_root(tree_root->nodesize, tree_root->sectorsize,
1507                 tree_root->stripesize, root, fs_info, key->objectid);
1508
1509         ret = btrfs_find_root(tree_root, key, path,
1510                               &root->root_item, &root->root_key);
1511         if (ret) {
1512                 if (ret > 0)
1513                         ret = -ENOENT;
1514                 goto find_fail;
1515         }
1516
1517         generation = btrfs_root_generation(&root->root_item);
1518         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1519                                      generation);
1520         if (!root->node) {
1521                 ret = -ENOMEM;
1522                 goto find_fail;
1523         } else if (!btrfs_buffer_uptodate(root->node, generation, 0)) {
1524                 ret = -EIO;
1525                 goto read_fail;
1526         }
1527         root->commit_root = btrfs_root_node(root);
1528 out:
1529         btrfs_free_path(path);
1530         return root;
1531
1532 read_fail:
1533         free_extent_buffer(root->node);
1534 find_fail:
1535         kfree(root);
1536 alloc_fail:
1537         root = ERR_PTR(ret);
1538         goto out;
1539 }
1540
1541 struct btrfs_root *btrfs_read_fs_root(struct btrfs_root *tree_root,
1542                                       struct btrfs_key *location)
1543 {
1544         struct btrfs_root *root;
1545
1546         root = btrfs_read_tree_root(tree_root, location);
1547         if (IS_ERR(root))
1548                 return root;
1549
1550         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
1551                 set_bit(BTRFS_ROOT_REF_COWS, &root->state);
1552                 btrfs_check_and_init_root_item(&root->root_item);
1553         }
1554
1555         return root;
1556 }
1557
1558 int btrfs_init_fs_root(struct btrfs_root *root)
1559 {
1560         int ret;
1561         struct btrfs_subvolume_writers *writers;
1562
1563         root->free_ino_ctl = kzalloc(sizeof(*root->free_ino_ctl), GFP_NOFS);
1564         root->free_ino_pinned = kzalloc(sizeof(*root->free_ino_pinned),
1565                                         GFP_NOFS);
1566         if (!root->free_ino_pinned || !root->free_ino_ctl) {
1567                 ret = -ENOMEM;
1568                 goto fail;
1569         }
1570
1571         writers = btrfs_alloc_subvolume_writers();
1572         if (IS_ERR(writers)) {
1573                 ret = PTR_ERR(writers);
1574                 goto fail;
1575         }
1576         root->subv_writers = writers;
1577
1578         btrfs_init_free_ino_ctl(root);
1579         spin_lock_init(&root->ino_cache_lock);
1580         init_waitqueue_head(&root->ino_cache_wait);
1581
1582         ret = get_anon_bdev(&root->anon_dev);
1583         if (ret)
1584                 goto free_writers;
1585         return 0;
1586
1587 free_writers:
1588         btrfs_free_subvolume_writers(root->subv_writers);
1589 fail:
1590         kfree(root->free_ino_ctl);
1591         kfree(root->free_ino_pinned);
1592         return ret;
1593 }
1594
1595 static struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1596                                                u64 root_id)
1597 {
1598         struct btrfs_root *root;
1599
1600         spin_lock(&fs_info->fs_roots_radix_lock);
1601         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1602                                  (unsigned long)root_id);
1603         spin_unlock(&fs_info->fs_roots_radix_lock);
1604         return root;
1605 }
1606
1607 int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
1608                          struct btrfs_root *root)
1609 {
1610         int ret;
1611
1612         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1613         if (ret)
1614                 return ret;
1615
1616         spin_lock(&fs_info->fs_roots_radix_lock);
1617         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1618                                 (unsigned long)root->root_key.objectid,
1619                                 root);
1620         if (ret == 0)
1621                 set_bit(BTRFS_ROOT_IN_RADIX, &root->state);
1622         spin_unlock(&fs_info->fs_roots_radix_lock);
1623         radix_tree_preload_end();
1624
1625         return ret;
1626 }
1627
1628 struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
1629                                      struct btrfs_key *location,
1630                                      bool check_ref)
1631 {
1632         struct btrfs_root *root;
1633         int ret;
1634
1635         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1636                 return fs_info->tree_root;
1637         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1638                 return fs_info->extent_root;
1639         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1640                 return fs_info->chunk_root;
1641         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1642                 return fs_info->dev_root;
1643         if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1644                 return fs_info->csum_root;
1645         if (location->objectid == BTRFS_QUOTA_TREE_OBJECTID)
1646                 return fs_info->quota_root ? fs_info->quota_root :
1647                                              ERR_PTR(-ENOENT);
1648         if (location->objectid == BTRFS_UUID_TREE_OBJECTID)
1649                 return fs_info->uuid_root ? fs_info->uuid_root :
1650                                             ERR_PTR(-ENOENT);
1651 again:
1652         root = btrfs_lookup_fs_root(fs_info, location->objectid);
1653         if (root) {
1654                 if (check_ref && btrfs_root_refs(&root->root_item) == 0)
1655                         return ERR_PTR(-ENOENT);
1656                 return root;
1657         }
1658
1659         root = btrfs_read_fs_root(fs_info->tree_root, location);
1660         if (IS_ERR(root))
1661                 return root;
1662
1663         if (check_ref && btrfs_root_refs(&root->root_item) == 0) {
1664                 ret = -ENOENT;
1665                 goto fail;
1666         }
1667
1668         ret = btrfs_init_fs_root(root);
1669         if (ret)
1670                 goto fail;
1671
1672         ret = btrfs_find_item(fs_info->tree_root, NULL, BTRFS_ORPHAN_OBJECTID,
1673                         location->objectid, BTRFS_ORPHAN_ITEM_KEY, NULL);
1674         if (ret < 0)
1675                 goto fail;
1676         if (ret == 0)
1677                 set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
1678
1679         ret = btrfs_insert_fs_root(fs_info, root);
1680         if (ret) {
1681                 if (ret == -EEXIST) {
1682                         free_fs_root(root);
1683                         goto again;
1684                 }
1685                 goto fail;
1686         }
1687         return root;
1688 fail:
1689         free_fs_root(root);
1690         return ERR_PTR(ret);
1691 }
1692
1693 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1694 {
1695         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1696         int ret = 0;
1697         struct btrfs_device *device;
1698         struct backing_dev_info *bdi;
1699
1700         rcu_read_lock();
1701         list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
1702                 if (!device->bdev)
1703                         continue;
1704                 bdi = blk_get_backing_dev_info(device->bdev);
1705                 if (bdi && bdi_congested(bdi, bdi_bits)) {
1706                         ret = 1;
1707                         break;
1708                 }
1709         }
1710         rcu_read_unlock();
1711         return ret;
1712 }
1713
1714 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1715 {
1716         int err;
1717
1718         bdi->capabilities = BDI_CAP_MAP_COPY;
1719         err = bdi_setup_and_register(bdi, "btrfs", BDI_CAP_MAP_COPY);
1720         if (err)
1721                 return err;
1722
1723         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1724         bdi->congested_fn       = btrfs_congested_fn;
1725         bdi->congested_data     = info;
1726         return 0;
1727 }
1728
1729 /*
1730  * called by the kthread helper functions to finally call the bio end_io
1731  * functions.  This is where read checksum verification actually happens
1732  */
1733 static void end_workqueue_fn(struct btrfs_work *work)
1734 {
1735         struct bio *bio;
1736         struct btrfs_end_io_wq *end_io_wq;
1737         int error;
1738
1739         end_io_wq = container_of(work, struct btrfs_end_io_wq, work);
1740         bio = end_io_wq->bio;
1741
1742         error = end_io_wq->error;
1743         bio->bi_private = end_io_wq->private;
1744         bio->bi_end_io = end_io_wq->end_io;
1745         kmem_cache_free(btrfs_end_io_wq_cache, end_io_wq);
1746         bio_endio_nodec(bio, error);
1747 }
1748
1749 static int cleaner_kthread(void *arg)
1750 {
1751         struct btrfs_root *root = arg;
1752         int again;
1753
1754         do {
1755                 again = 0;
1756
1757                 /* Make the cleaner go to sleep early. */
1758                 if (btrfs_need_cleaner_sleep(root))
1759                         goto sleep;
1760
1761                 if (!mutex_trylock(&root->fs_info->cleaner_mutex))
1762                         goto sleep;
1763
1764                 /*
1765                  * Avoid the problem that we change the status of the fs
1766                  * during the above check and trylock.
1767                  */
1768                 if (btrfs_need_cleaner_sleep(root)) {
1769                         mutex_unlock(&root->fs_info->cleaner_mutex);
1770                         goto sleep;
1771                 }
1772
1773                 btrfs_run_delayed_iputs(root);
1774                 btrfs_delete_unused_bgs(root->fs_info);
1775                 again = btrfs_clean_one_deleted_snapshot(root);
1776                 mutex_unlock(&root->fs_info->cleaner_mutex);
1777
1778                 /*
1779                  * The defragger has dealt with the R/O remount and umount,
1780                  * needn't do anything special here.
1781                  */
1782                 btrfs_run_defrag_inodes(root->fs_info);
1783 sleep:
1784                 if (!try_to_freeze() && !again) {
1785                         set_current_state(TASK_INTERRUPTIBLE);
1786                         if (!kthread_should_stop())
1787                                 schedule();
1788                         __set_current_state(TASK_RUNNING);
1789                 }
1790         } while (!kthread_should_stop());
1791         return 0;
1792 }
1793
1794 static int transaction_kthread(void *arg)
1795 {
1796         struct btrfs_root *root = arg;
1797         struct btrfs_trans_handle *trans;
1798         struct btrfs_transaction *cur;
1799         u64 transid;
1800         unsigned long now;
1801         unsigned long delay;
1802         bool cannot_commit;
1803
1804         do {
1805                 cannot_commit = false;
1806                 delay = HZ * root->fs_info->commit_interval;
1807                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1808
1809                 spin_lock(&root->fs_info->trans_lock);
1810                 cur = root->fs_info->running_transaction;
1811                 if (!cur) {
1812                         spin_unlock(&root->fs_info->trans_lock);
1813                         goto sleep;
1814                 }
1815
1816                 now = get_seconds();
1817                 if (cur->state < TRANS_STATE_BLOCKED &&
1818                     (now < cur->start_time ||
1819                      now - cur->start_time < root->fs_info->commit_interval)) {
1820                         spin_unlock(&root->fs_info->trans_lock);
1821                         delay = HZ * 5;
1822                         goto sleep;
1823                 }
1824                 transid = cur->transid;
1825                 spin_unlock(&root->fs_info->trans_lock);
1826
1827                 /* If the file system is aborted, this will always fail. */
1828                 trans = btrfs_attach_transaction(root);
1829                 if (IS_ERR(trans)) {
1830                         if (PTR_ERR(trans) != -ENOENT)
1831                                 cannot_commit = true;
1832                         goto sleep;
1833                 }
1834                 if (transid == trans->transid) {
1835                         btrfs_commit_transaction(trans, root);
1836                 } else {
1837                         btrfs_end_transaction(trans, root);
1838                 }
1839 sleep:
1840                 wake_up_process(root->fs_info->cleaner_kthread);
1841                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1842
1843                 if (unlikely(test_bit(BTRFS_FS_STATE_ERROR,
1844                                       &root->fs_info->fs_state)))
1845                         btrfs_cleanup_transaction(root);
1846                 if (!try_to_freeze()) {
1847                         set_current_state(TASK_INTERRUPTIBLE);
1848                         if (!kthread_should_stop() &&
1849                             (!btrfs_transaction_blocked(root->fs_info) ||
1850                              cannot_commit))
1851                                 schedule_timeout(delay);
1852                         __set_current_state(TASK_RUNNING);
1853                 }
1854         } while (!kthread_should_stop());
1855         return 0;
1856 }
1857
1858 /*
1859  * this will find the highest generation in the array of
1860  * root backups.  The index of the highest array is returned,
1861  * or -1 if we can't find anything.
1862  *
1863  * We check to make sure the array is valid by comparing the
1864  * generation of the latest  root in the array with the generation
1865  * in the super block.  If they don't match we pitch it.
1866  */
1867 static int find_newest_super_backup(struct btrfs_fs_info *info, u64 newest_gen)
1868 {
1869         u64 cur;
1870         int newest_index = -1;
1871         struct btrfs_root_backup *root_backup;
1872         int i;
1873
1874         for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
1875                 root_backup = info->super_copy->super_roots + i;
1876                 cur = btrfs_backup_tree_root_gen(root_backup);
1877                 if (cur == newest_gen)
1878                         newest_index = i;
1879         }
1880
1881         /* check to see if we actually wrapped around */
1882         if (newest_index == BTRFS_NUM_BACKUP_ROOTS - 1) {
1883                 root_backup = info->super_copy->super_roots;
1884                 cur = btrfs_backup_tree_root_gen(root_backup);
1885                 if (cur == newest_gen)
1886                         newest_index = 0;
1887         }
1888         return newest_index;
1889 }
1890
1891
1892 /*
1893  * find the oldest backup so we know where to store new entries
1894  * in the backup array.  This will set the backup_root_index
1895  * field in the fs_info struct
1896  */
1897 static void find_oldest_super_backup(struct btrfs_fs_info *info,
1898                                      u64 newest_gen)
1899 {
1900         int newest_index = -1;
1901
1902         newest_index = find_newest_super_backup(info, newest_gen);
1903         /* if there was garbage in there, just move along */
1904         if (newest_index == -1) {
1905                 info->backup_root_index = 0;
1906         } else {
1907                 info->backup_root_index = (newest_index + 1) % BTRFS_NUM_BACKUP_ROOTS;
1908         }
1909 }
1910
1911 /*
1912  * copy all the root pointers into the super backup array.
1913  * this will bump the backup pointer by one when it is
1914  * done
1915  */
1916 static void backup_super_roots(struct btrfs_fs_info *info)
1917 {
1918         int next_backup;
1919         struct btrfs_root_backup *root_backup;
1920         int last_backup;
1921
1922         next_backup = info->backup_root_index;
1923         last_backup = (next_backup + BTRFS_NUM_BACKUP_ROOTS - 1) %
1924                 BTRFS_NUM_BACKUP_ROOTS;
1925
1926         /*
1927          * just overwrite the last backup if we're at the same generation
1928          * this happens only at umount
1929          */
1930         root_backup = info->super_for_commit->super_roots + last_backup;
1931         if (btrfs_backup_tree_root_gen(root_backup) ==
1932             btrfs_header_generation(info->tree_root->node))
1933                 next_backup = last_backup;
1934
1935         root_backup = info->super_for_commit->super_roots + next_backup;
1936
1937         /*
1938          * make sure all of our padding and empty slots get zero filled
1939          * regardless of which ones we use today
1940          */
1941         memset(root_backup, 0, sizeof(*root_backup));
1942
1943         info->backup_root_index = (next_backup + 1) % BTRFS_NUM_BACKUP_ROOTS;
1944
1945         btrfs_set_backup_tree_root(root_backup, info->tree_root->node->start);
1946         btrfs_set_backup_tree_root_gen(root_backup,
1947                                btrfs_header_generation(info->tree_root->node));
1948
1949         btrfs_set_backup_tree_root_level(root_backup,
1950                                btrfs_header_level(info->tree_root->node));
1951
1952         btrfs_set_backup_chunk_root(root_backup, info->chunk_root->node->start);
1953         btrfs_set_backup_chunk_root_gen(root_backup,
1954                                btrfs_header_generation(info->chunk_root->node));
1955         btrfs_set_backup_chunk_root_level(root_backup,
1956                                btrfs_header_level(info->chunk_root->node));
1957
1958         btrfs_set_backup_extent_root(root_backup, info->extent_root->node->start);
1959         btrfs_set_backup_extent_root_gen(root_backup,
1960                                btrfs_header_generation(info->extent_root->node));
1961         btrfs_set_backup_extent_root_level(root_backup,
1962                                btrfs_header_level(info->extent_root->node));
1963
1964         /*
1965          * we might commit during log recovery, which happens before we set
1966          * the fs_root.  Make sure it is valid before we fill it in.
1967          */
1968         if (info->fs_root && info->fs_root->node) {
1969                 btrfs_set_backup_fs_root(root_backup,
1970                                          info->fs_root->node->start);
1971                 btrfs_set_backup_fs_root_gen(root_backup,
1972                                btrfs_header_generation(info->fs_root->node));
1973                 btrfs_set_backup_fs_root_level(root_backup,
1974                                btrfs_header_level(info->fs_root->node));
1975         }
1976
1977         btrfs_set_backup_dev_root(root_backup, info->dev_root->node->start);
1978         btrfs_set_backup_dev_root_gen(root_backup,
1979                                btrfs_header_generation(info->dev_root->node));
1980         btrfs_set_backup_dev_root_level(root_backup,
1981                                        btrfs_header_level(info->dev_root->node));
1982
1983         btrfs_set_backup_csum_root(root_backup, info->csum_root->node->start);
1984         btrfs_set_backup_csum_root_gen(root_backup,
1985                                btrfs_header_generation(info->csum_root->node));
1986         btrfs_set_backup_csum_root_level(root_backup,
1987                                btrfs_header_level(info->csum_root->node));
1988
1989         btrfs_set_backup_total_bytes(root_backup,
1990                              btrfs_super_total_bytes(info->super_copy));
1991         btrfs_set_backup_bytes_used(root_backup,
1992                              btrfs_super_bytes_used(info->super_copy));
1993         btrfs_set_backup_num_devices(root_backup,
1994                              btrfs_super_num_devices(info->super_copy));
1995
1996         /*
1997          * if we don't copy this out to the super_copy, it won't get remembered
1998          * for the next commit
1999          */
2000         memcpy(&info->super_copy->super_roots,
2001                &info->super_for_commit->super_roots,
2002                sizeof(*root_backup) * BTRFS_NUM_BACKUP_ROOTS);
2003 }
2004
2005 /*
2006  * this copies info out of the root backup array and back into
2007  * the in-memory super block.  It is meant to help iterate through
2008  * the array, so you send it the number of backups you've already
2009  * tried and the last backup index you used.
2010  *
2011  * this returns -1 when it has tried all the backups
2012  */
2013 static noinline int next_root_backup(struct btrfs_fs_info *info,
2014                                      struct btrfs_super_block *super,
2015                                      int *num_backups_tried, int *backup_index)
2016 {
2017         struct btrfs_root_backup *root_backup;
2018         int newest = *backup_index;
2019
2020         if (*num_backups_tried == 0) {
2021                 u64 gen = btrfs_super_generation(super);
2022
2023                 newest = find_newest_super_backup(info, gen);
2024                 if (newest == -1)
2025                         return -1;
2026
2027                 *backup_index = newest;
2028                 *num_backups_tried = 1;
2029         } else if (*num_backups_tried == BTRFS_NUM_BACKUP_ROOTS) {
2030                 /* we've tried all the backups, all done */
2031                 return -1;
2032         } else {
2033                 /* jump to the next oldest backup */
2034                 newest = (*backup_index + BTRFS_NUM_BACKUP_ROOTS - 1) %
2035                         BTRFS_NUM_BACKUP_ROOTS;
2036                 *backup_index = newest;
2037                 *num_backups_tried += 1;
2038         }
2039         root_backup = super->super_roots + newest;
2040
2041         btrfs_set_super_generation(super,
2042                                    btrfs_backup_tree_root_gen(root_backup));
2043         btrfs_set_super_root(super, btrfs_backup_tree_root(root_backup));
2044         btrfs_set_super_root_level(super,
2045                                    btrfs_backup_tree_root_level(root_backup));
2046         btrfs_set_super_bytes_used(super, btrfs_backup_bytes_used(root_backup));
2047
2048         /*
2049          * fixme: the total bytes and num_devices need to match or we should
2050          * need a fsck
2051          */
2052         btrfs_set_super_total_bytes(super, btrfs_backup_total_bytes(root_backup));
2053         btrfs_set_super_num_devices(super, btrfs_backup_num_devices(root_backup));
2054         return 0;
2055 }
2056
2057 /* helper to cleanup workers */
2058 static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
2059 {
2060         btrfs_destroy_workqueue(fs_info->fixup_workers);
2061         btrfs_destroy_workqueue(fs_info->delalloc_workers);
2062         btrfs_destroy_workqueue(fs_info->workers);
2063         btrfs_destroy_workqueue(fs_info->endio_workers);
2064         btrfs_destroy_workqueue(fs_info->endio_meta_workers);
2065         btrfs_destroy_workqueue(fs_info->endio_raid56_workers);
2066         btrfs_destroy_workqueue(fs_info->endio_repair_workers);
2067         btrfs_destroy_workqueue(fs_info->rmw_workers);
2068         btrfs_destroy_workqueue(fs_info->endio_meta_write_workers);
2069         btrfs_destroy_workqueue(fs_info->endio_write_workers);
2070         btrfs_destroy_workqueue(fs_info->endio_freespace_worker);
2071         btrfs_destroy_workqueue(fs_info->submit_workers);
2072         btrfs_destroy_workqueue(fs_info->delayed_workers);
2073         btrfs_destroy_workqueue(fs_info->caching_workers);
2074         btrfs_destroy_workqueue(fs_info->readahead_workers);
2075         btrfs_destroy_workqueue(fs_info->flush_workers);
2076         btrfs_destroy_workqueue(fs_info->qgroup_rescan_workers);
2077         btrfs_destroy_workqueue(fs_info->extent_workers);
2078 }
2079
2080 static void free_root_extent_buffers(struct btrfs_root *root)
2081 {
2082         if (root) {
2083                 free_extent_buffer(root->node);
2084                 free_extent_buffer(root->commit_root);
2085                 root->node = NULL;
2086                 root->commit_root = NULL;
2087         }
2088 }
2089
2090 /* helper to cleanup tree roots */
2091 static void free_root_pointers(struct btrfs_fs_info *info, int chunk_root)
2092 {
2093         free_root_extent_buffers(info->tree_root);
2094
2095         free_root_extent_buffers(info->dev_root);
2096         free_root_extent_buffers(info->extent_root);
2097         free_root_extent_buffers(info->csum_root);
2098         free_root_extent_buffers(info->quota_root);
2099         free_root_extent_buffers(info->uuid_root);
2100         if (chunk_root)
2101                 free_root_extent_buffers(info->chunk_root);
2102 }
2103
2104 void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info)
2105 {
2106         int ret;
2107         struct btrfs_root *gang[8];
2108         int i;
2109
2110         while (!list_empty(&fs_info->dead_roots)) {
2111                 gang[0] = list_entry(fs_info->dead_roots.next,
2112                                      struct btrfs_root, root_list);
2113                 list_del(&gang[0]->root_list);
2114
2115                 if (test_bit(BTRFS_ROOT_IN_RADIX, &gang[0]->state)) {
2116                         btrfs_drop_and_free_fs_root(fs_info, gang[0]);
2117                 } else {
2118                         free_extent_buffer(gang[0]->node);
2119                         free_extent_buffer(gang[0]->commit_root);
2120                         btrfs_put_fs_root(gang[0]);
2121                 }
2122         }
2123
2124         while (1) {
2125                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2126                                              (void **)gang, 0,
2127                                              ARRAY_SIZE(gang));
2128                 if (!ret)
2129                         break;
2130                 for (i = 0; i < ret; i++)
2131                         btrfs_drop_and_free_fs_root(fs_info, gang[i]);
2132         }
2133
2134         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
2135                 btrfs_free_log_root_tree(NULL, fs_info);
2136                 btrfs_destroy_pinned_extent(fs_info->tree_root,
2137                                             fs_info->pinned_extents);
2138         }
2139 }
2140
2141 int open_ctree(struct super_block *sb,
2142                struct btrfs_fs_devices *fs_devices,
2143                char *options)
2144 {
2145         u32 sectorsize;
2146         u32 nodesize;
2147         u32 stripesize;
2148         u64 generation;
2149         u64 features;
2150         struct btrfs_key location;
2151         struct buffer_head *bh;
2152         struct btrfs_super_block *disk_super;
2153         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2154         struct btrfs_root *tree_root;
2155         struct btrfs_root *extent_root;
2156         struct btrfs_root *csum_root;
2157         struct btrfs_root *chunk_root;
2158         struct btrfs_root *dev_root;
2159         struct btrfs_root *quota_root;
2160         struct btrfs_root *uuid_root;
2161         struct btrfs_root *log_tree_root;
2162         int ret;
2163         int err = -EINVAL;
2164         int num_backups_tried = 0;
2165         int backup_index = 0;
2166         int max_active;
2167         int flags = WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_UNBOUND;
2168         bool create_uuid_tree;
2169         bool check_uuid_tree;
2170
2171         tree_root = fs_info->tree_root = btrfs_alloc_root(fs_info);
2172         chunk_root = fs_info->chunk_root = btrfs_alloc_root(fs_info);
2173         if (!tree_root || !chunk_root) {
2174                 err = -ENOMEM;
2175                 goto fail;
2176         }
2177
2178         ret = init_srcu_struct(&fs_info->subvol_srcu);
2179         if (ret) {
2180                 err = ret;
2181                 goto fail;
2182         }
2183
2184         ret = setup_bdi(fs_info, &fs_info->bdi);
2185         if (ret) {
2186                 err = ret;
2187                 goto fail_srcu;
2188         }
2189
2190         ret = percpu_counter_init(&fs_info->dirty_metadata_bytes, 0, GFP_KERNEL);
2191         if (ret) {
2192                 err = ret;
2193                 goto fail_bdi;
2194         }
2195         fs_info->dirty_metadata_batch = PAGE_CACHE_SIZE *
2196                                         (1 + ilog2(nr_cpu_ids));
2197
2198         ret = percpu_counter_init(&fs_info->delalloc_bytes, 0, GFP_KERNEL);
2199         if (ret) {
2200                 err = ret;
2201                 goto fail_dirty_metadata_bytes;
2202         }
2203
2204         ret = percpu_counter_init(&fs_info->bio_counter, 0, GFP_KERNEL);
2205         if (ret) {
2206                 err = ret;
2207                 goto fail_delalloc_bytes;
2208         }
2209
2210         fs_info->btree_inode = new_inode(sb);
2211         if (!fs_info->btree_inode) {
2212                 err = -ENOMEM;
2213                 goto fail_bio_counter;
2214         }
2215
2216         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
2217
2218         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
2219         INIT_RADIX_TREE(&fs_info->buffer_radix, GFP_ATOMIC);
2220         INIT_LIST_HEAD(&fs_info->trans_list);
2221         INIT_LIST_HEAD(&fs_info->dead_roots);
2222         INIT_LIST_HEAD(&fs_info->delayed_iputs);
2223         INIT_LIST_HEAD(&fs_info->delalloc_roots);
2224         INIT_LIST_HEAD(&fs_info->caching_block_groups);
2225         spin_lock_init(&fs_info->delalloc_root_lock);
2226         spin_lock_init(&fs_info->trans_lock);
2227         spin_lock_init(&fs_info->fs_roots_radix_lock);
2228         spin_lock_init(&fs_info->delayed_iput_lock);
2229         spin_lock_init(&fs_info->defrag_inodes_lock);
2230         spin_lock_init(&fs_info->free_chunk_lock);
2231         spin_lock_init(&fs_info->tree_mod_seq_lock);
2232         spin_lock_init(&fs_info->super_lock);
2233         spin_lock_init(&fs_info->qgroup_op_lock);
2234         spin_lock_init(&fs_info->buffer_lock);
2235         spin_lock_init(&fs_info->unused_bgs_lock);
2236         rwlock_init(&fs_info->tree_mod_log_lock);
2237         mutex_init(&fs_info->reloc_mutex);
2238         mutex_init(&fs_info->delalloc_root_mutex);
2239         seqlock_init(&fs_info->profiles_lock);
2240
2241         init_completion(&fs_info->kobj_unregister);
2242         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
2243         INIT_LIST_HEAD(&fs_info->space_info);
2244         INIT_LIST_HEAD(&fs_info->tree_mod_seq_list);
2245         INIT_LIST_HEAD(&fs_info->unused_bgs);
2246         btrfs_mapping_init(&fs_info->mapping_tree);
2247         btrfs_init_block_rsv(&fs_info->global_block_rsv,
2248                              BTRFS_BLOCK_RSV_GLOBAL);
2249         btrfs_init_block_rsv(&fs_info->delalloc_block_rsv,
2250                              BTRFS_BLOCK_RSV_DELALLOC);
2251         btrfs_init_block_rsv(&fs_info->trans_block_rsv, BTRFS_BLOCK_RSV_TRANS);
2252         btrfs_init_block_rsv(&fs_info->chunk_block_rsv, BTRFS_BLOCK_RSV_CHUNK);
2253         btrfs_init_block_rsv(&fs_info->empty_block_rsv, BTRFS_BLOCK_RSV_EMPTY);
2254         btrfs_init_block_rsv(&fs_info->delayed_block_rsv,
2255                              BTRFS_BLOCK_RSV_DELOPS);
2256         atomic_set(&fs_info->nr_async_submits, 0);
2257         atomic_set(&fs_info->async_delalloc_pages, 0);
2258         atomic_set(&fs_info->async_submit_draining, 0);
2259         atomic_set(&fs_info->nr_async_bios, 0);
2260         atomic_set(&fs_info->defrag_running, 0);
2261         atomic_set(&fs_info->qgroup_op_seq, 0);
2262         atomic64_set(&fs_info->tree_mod_seq, 0);
2263         fs_info->sb = sb;
2264         fs_info->max_inline = BTRFS_DEFAULT_MAX_INLINE;
2265         fs_info->metadata_ratio = 0;
2266         fs_info->defrag_inodes = RB_ROOT;
2267         fs_info->free_chunk_space = 0;
2268         fs_info->tree_mod_log = RB_ROOT;
2269         fs_info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
2270         fs_info->avg_delayed_ref_runtime = div64_u64(NSEC_PER_SEC, 64);
2271         /* readahead state */
2272         INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_WAIT);
2273         spin_lock_init(&fs_info->reada_lock);
2274
2275         fs_info->thread_pool_size = min_t(unsigned long,
2276                                           num_online_cpus() + 2, 8);
2277
2278         INIT_LIST_HEAD(&fs_info->ordered_roots);
2279         spin_lock_init(&fs_info->ordered_root_lock);
2280         fs_info->delayed_root = kmalloc(sizeof(struct btrfs_delayed_root),
2281                                         GFP_NOFS);
2282         if (!fs_info->delayed_root) {
2283                 err = -ENOMEM;
2284                 goto fail_iput;
2285         }
2286         btrfs_init_delayed_root(fs_info->delayed_root);
2287
2288         mutex_init(&fs_info->scrub_lock);
2289         atomic_set(&fs_info->scrubs_running, 0);
2290         atomic_set(&fs_info->scrub_pause_req, 0);
2291         atomic_set(&fs_info->scrubs_paused, 0);
2292         atomic_set(&fs_info->scrub_cancel_req, 0);
2293         init_waitqueue_head(&fs_info->replace_wait);
2294         init_waitqueue_head(&fs_info->scrub_pause_wait);
2295         fs_info->scrub_workers_refcnt = 0;
2296 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2297         fs_info->check_integrity_print_mask = 0;
2298 #endif
2299
2300         spin_lock_init(&fs_info->balance_lock);
2301         mutex_init(&fs_info->balance_mutex);
2302         atomic_set(&fs_info->balance_running, 0);
2303         atomic_set(&fs_info->balance_pause_req, 0);
2304         atomic_set(&fs_info->balance_cancel_req, 0);
2305         fs_info->balance_ctl = NULL;
2306         init_waitqueue_head(&fs_info->balance_wait_q);
2307         btrfs_init_async_reclaim_work(&fs_info->async_reclaim_work);
2308
2309         sb->s_blocksize = 4096;
2310         sb->s_blocksize_bits = blksize_bits(4096);
2311         sb->s_bdi = &fs_info->bdi;
2312
2313         fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
2314         set_nlink(fs_info->btree_inode, 1);
2315         /*
2316          * we set the i_size on the btree inode to the max possible int.
2317          * the real end of the address space is determined by all of
2318          * the devices in the system
2319          */
2320         fs_info->btree_inode->i_size = OFFSET_MAX;
2321         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
2322         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
2323
2324         RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
2325         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
2326                              fs_info->btree_inode->i_mapping);
2327         BTRFS_I(fs_info->btree_inode)->io_tree.track_uptodate = 0;
2328         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree);
2329
2330         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
2331
2332         BTRFS_I(fs_info->btree_inode)->root = tree_root;
2333         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
2334                sizeof(struct btrfs_key));
2335         set_bit(BTRFS_INODE_DUMMY,
2336                 &BTRFS_I(fs_info->btree_inode)->runtime_flags);
2337         btrfs_insert_inode_hash(fs_info->btree_inode);
2338
2339         spin_lock_init(&fs_info->block_group_cache_lock);
2340         fs_info->block_group_cache_tree = RB_ROOT;
2341         fs_info->first_logical_byte = (u64)-1;
2342
2343         extent_io_tree_init(&fs_info->freed_extents[0],
2344                              fs_info->btree_inode->i_mapping);
2345         extent_io_tree_init(&fs_info->freed_extents[1],
2346                              fs_info->btree_inode->i_mapping);
2347         fs_info->pinned_extents = &fs_info->freed_extents[0];
2348         fs_info->do_barriers = 1;
2349
2350
2351         mutex_init(&fs_info->ordered_operations_mutex);
2352         mutex_init(&fs_info->ordered_extent_flush_mutex);
2353         mutex_init(&fs_info->tree_log_mutex);
2354         mutex_init(&fs_info->chunk_mutex);
2355         mutex_init(&fs_info->transaction_kthread_mutex);
2356         mutex_init(&fs_info->cleaner_mutex);
2357         mutex_init(&fs_info->volume_mutex);
2358         init_rwsem(&fs_info->commit_root_sem);
2359         init_rwsem(&fs_info->cleanup_work_sem);
2360         init_rwsem(&fs_info->subvol_sem);
2361         sema_init(&fs_info->uuid_tree_rescan_sem, 1);
2362         fs_info->dev_replace.lock_owner = 0;
2363         atomic_set(&fs_info->dev_replace.nesting_level, 0);
2364         mutex_init(&fs_info->dev_replace.lock_finishing_cancel_unmount);
2365         mutex_init(&fs_info->dev_replace.lock_management_lock);
2366         mutex_init(&fs_info->dev_replace.lock);
2367
2368         spin_lock_init(&fs_info->qgroup_lock);
2369         mutex_init(&fs_info->qgroup_ioctl_lock);
2370         fs_info->qgroup_tree = RB_ROOT;
2371         fs_info->qgroup_op_tree = RB_ROOT;
2372         INIT_LIST_HEAD(&fs_info->dirty_qgroups);
2373         fs_info->qgroup_seq = 1;
2374         fs_info->quota_enabled = 0;
2375         fs_info->pending_quota_state = 0;
2376         fs_info->qgroup_ulist = NULL;
2377         mutex_init(&fs_info->qgroup_rescan_lock);
2378
2379         btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
2380         btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
2381
2382         init_waitqueue_head(&fs_info->transaction_throttle);
2383         init_waitqueue_head(&fs_info->transaction_wait);
2384         init_waitqueue_head(&fs_info->transaction_blocked_wait);
2385         init_waitqueue_head(&fs_info->async_submit_wait);
2386
2387         ret = btrfs_alloc_stripe_hash_table(fs_info);
2388         if (ret) {
2389                 err = ret;
2390                 goto fail_alloc;
2391         }
2392
2393         __setup_root(4096, 4096, 4096, tree_root,
2394                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
2395
2396         invalidate_bdev(fs_devices->latest_bdev);
2397
2398         /*
2399          * Read super block and check the signature bytes only
2400          */
2401         bh = btrfs_read_dev_super(fs_devices->latest_bdev);
2402         if (!bh) {
2403                 err = -EINVAL;
2404                 goto fail_alloc;
2405         }
2406
2407         /*
2408          * We want to check superblock checksum, the type is stored inside.
2409          * Pass the whole disk block of size BTRFS_SUPER_INFO_SIZE (4k).
2410          */
2411         if (btrfs_check_super_csum(bh->b_data)) {
2412                 printk(KERN_ERR "BTRFS: superblock checksum mismatch\n");
2413                 err = -EINVAL;
2414                 goto fail_alloc;
2415         }
2416
2417         /*
2418          * super_copy is zeroed at allocation time and we never touch the
2419          * following bytes up to INFO_SIZE, the checksum is calculated from
2420          * the whole block of INFO_SIZE
2421          */
2422         memcpy(fs_info->super_copy, bh->b_data, sizeof(*fs_info->super_copy));
2423         memcpy(fs_info->super_for_commit, fs_info->super_copy,
2424                sizeof(*fs_info->super_for_commit));
2425         brelse(bh);
2426
2427         memcpy(fs_info->fsid, fs_info->super_copy->fsid, BTRFS_FSID_SIZE);
2428
2429         ret = btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
2430         if (ret) {
2431                 printk(KERN_ERR "BTRFS: superblock contains fatal errors\n");
2432                 err = -EINVAL;
2433                 goto fail_alloc;
2434         }
2435
2436         disk_super = fs_info->super_copy;
2437         if (!btrfs_super_root(disk_super))
2438                 goto fail_alloc;
2439
2440         /* check FS state, whether FS is broken. */
2441         if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_ERROR)
2442                 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
2443
2444         /*
2445          * run through our array of backup supers and setup
2446          * our ring pointer to the oldest one
2447          */
2448         generation = btrfs_super_generation(disk_super);
2449         find_oldest_super_backup(fs_info, generation);
2450
2451         /*
2452          * In the long term, we'll store the compression type in the super
2453          * block, and it'll be used for per file compression control.
2454          */
2455         fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
2456
2457         ret = btrfs_parse_options(tree_root, options);
2458         if (ret) {
2459                 err = ret;
2460                 goto fail_alloc;
2461         }
2462
2463         features = btrfs_super_incompat_flags(disk_super) &
2464                 ~BTRFS_FEATURE_INCOMPAT_SUPP;
2465         if (features) {
2466                 printk(KERN_ERR "BTRFS: couldn't mount because of "
2467                        "unsupported optional features (%Lx).\n",
2468                        features);
2469                 err = -EINVAL;
2470                 goto fail_alloc;
2471         }
2472
2473         /*
2474          * Leafsize and nodesize were always equal, this is only a sanity check.
2475          */
2476         if (le32_to_cpu(disk_super->__unused_leafsize) !=
2477             btrfs_super_nodesize(disk_super)) {
2478                 printk(KERN_ERR "BTRFS: couldn't mount because metadata "
2479                        "blocksizes don't match.  node %d leaf %d\n",
2480                        btrfs_super_nodesize(disk_super),
2481                        le32_to_cpu(disk_super->__unused_leafsize));
2482                 err = -EINVAL;
2483                 goto fail_alloc;
2484         }
2485         if (btrfs_super_nodesize(disk_super) > BTRFS_MAX_METADATA_BLOCKSIZE) {
2486                 printk(KERN_ERR "BTRFS: couldn't mount because metadata "
2487                        "blocksize (%d) was too large\n",
2488                        btrfs_super_nodesize(disk_super));
2489                 err = -EINVAL;
2490                 goto fail_alloc;
2491         }
2492
2493         features = btrfs_super_incompat_flags(disk_super);
2494         features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
2495         if (tree_root->fs_info->compress_type == BTRFS_COMPRESS_LZO)
2496                 features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
2497
2498         if (features & BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)
2499                 printk(KERN_ERR "BTRFS: has skinny extents\n");
2500
2501         /*
2502          * flag our filesystem as having big metadata blocks if
2503          * they are bigger than the page size
2504          */
2505         if (btrfs_super_nodesize(disk_super) > PAGE_CACHE_SIZE) {
2506                 if (!(features & BTRFS_FEATURE_INCOMPAT_BIG_METADATA))
2507                         printk(KERN_INFO "BTRFS: flagging fs with big metadata feature\n");
2508                 features |= BTRFS_FEATURE_INCOMPAT_BIG_METADATA;
2509         }
2510
2511         nodesize = btrfs_super_nodesize(disk_super);
2512         sectorsize = btrfs_super_sectorsize(disk_super);
2513         stripesize = btrfs_super_stripesize(disk_super);
2514         fs_info->dirty_metadata_batch = nodesize * (1 + ilog2(nr_cpu_ids));
2515         fs_info->delalloc_batch = sectorsize * 512 * (1 + ilog2(nr_cpu_ids));
2516
2517         /*
2518          * mixed block groups end up with duplicate but slightly offset
2519          * extent buffers for the same range.  It leads to corruptions
2520          */
2521         if ((features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS) &&
2522             (sectorsize != nodesize)) {
2523                 printk(KERN_WARNING "BTRFS: unequal leaf/node/sector sizes "
2524                                 "are not allowed for mixed block groups on %s\n",
2525                                 sb->s_id);
2526                 goto fail_alloc;
2527         }
2528
2529         /*
2530          * Needn't use the lock because there is no other task which will
2531          * update the flag.
2532          */
2533         btrfs_set_super_incompat_flags(disk_super, features);
2534
2535         features = btrfs_super_compat_ro_flags(disk_super) &
2536                 ~BTRFS_FEATURE_COMPAT_RO_SUPP;
2537         if (!(sb->s_flags & MS_RDONLY) && features) {
2538                 printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
2539                        "unsupported option features (%Lx).\n",
2540                        features);
2541                 err = -EINVAL;
2542                 goto fail_alloc;
2543         }
2544
2545         max_active = fs_info->thread_pool_size;
2546
2547         fs_info->workers =
2548                 btrfs_alloc_workqueue("worker", flags | WQ_HIGHPRI,
2549                                       max_active, 16);
2550
2551         fs_info->delalloc_workers =
2552                 btrfs_alloc_workqueue("delalloc", flags, max_active, 2);
2553
2554         fs_info->flush_workers =
2555                 btrfs_alloc_workqueue("flush_delalloc", flags, max_active, 0);
2556
2557         fs_info->caching_workers =
2558                 btrfs_alloc_workqueue("cache", flags, max_active, 0);
2559
2560         /*
2561          * a higher idle thresh on the submit workers makes it much more
2562          * likely that bios will be send down in a sane order to the
2563          * devices
2564          */
2565         fs_info->submit_workers =
2566                 btrfs_alloc_workqueue("submit", flags,
2567                                       min_t(u64, fs_devices->num_devices,
2568                                             max_active), 64);
2569
2570         fs_info->fixup_workers =
2571                 btrfs_alloc_workqueue("fixup", flags, 1, 0);
2572
2573         /*
2574          * endios are largely parallel and should have a very
2575          * low idle thresh
2576          */
2577         fs_info->endio_workers =
2578                 btrfs_alloc_workqueue("endio", flags, max_active, 4);
2579         fs_info->endio_meta_workers =
2580                 btrfs_alloc_workqueue("endio-meta", flags, max_active, 4);
2581         fs_info->endio_meta_write_workers =
2582                 btrfs_alloc_workqueue("endio-meta-write", flags, max_active, 2);
2583         fs_info->endio_raid56_workers =
2584                 btrfs_alloc_workqueue("endio-raid56", flags, max_active, 4);
2585         fs_info->endio_repair_workers =
2586                 btrfs_alloc_workqueue("endio-repair", flags, 1, 0);
2587         fs_info->rmw_workers =
2588                 btrfs_alloc_workqueue("rmw", flags, max_active, 2);
2589         fs_info->endio_write_workers =
2590                 btrfs_alloc_workqueue("endio-write", flags, max_active, 2);
2591         fs_info->endio_freespace_worker =
2592                 btrfs_alloc_workqueue("freespace-write", flags, max_active, 0);
2593         fs_info->delayed_workers =
2594                 btrfs_alloc_workqueue("delayed-meta", flags, max_active, 0);
2595         fs_info->readahead_workers =
2596                 btrfs_alloc_workqueue("readahead", flags, max_active, 2);
2597         fs_info->qgroup_rescan_workers =
2598                 btrfs_alloc_workqueue("qgroup-rescan", flags, 1, 0);
2599         fs_info->extent_workers =
2600                 btrfs_alloc_workqueue("extent-refs", flags,
2601                                       min_t(u64, fs_devices->num_devices,
2602                                             max_active), 8);
2603
2604         if (!(fs_info->workers && fs_info->delalloc_workers &&
2605               fs_info->submit_workers && fs_info->flush_workers &&
2606               fs_info->endio_workers && fs_info->endio_meta_workers &&
2607               fs_info->endio_meta_write_workers &&
2608               fs_info->endio_repair_workers &&
2609               fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
2610               fs_info->endio_freespace_worker && fs_info->rmw_workers &&
2611               fs_info->caching_workers && fs_info->readahead_workers &&
2612               fs_info->fixup_workers && fs_info->delayed_workers &&
2613               fs_info->extent_workers &&
2614               fs_info->qgroup_rescan_workers)) {
2615                 err = -ENOMEM;
2616                 goto fail_sb_buffer;
2617         }
2618
2619         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
2620         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
2621                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
2622
2623         tree_root->nodesize = nodesize;
2624         tree_root->sectorsize = sectorsize;
2625         tree_root->stripesize = stripesize;
2626
2627         sb->s_blocksize = sectorsize;
2628         sb->s_blocksize_bits = blksize_bits(sectorsize);
2629
2630         if (btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
2631                 printk(KERN_INFO "BTRFS: valid FS not found on %s\n", sb->s_id);
2632                 goto fail_sb_buffer;
2633         }
2634
2635         if (sectorsize != PAGE_SIZE) {
2636                 printk(KERN_WARNING "BTRFS: Incompatible sector size(%lu) "
2637                        "found on %s\n", (unsigned long)sectorsize, sb->s_id);
2638                 goto fail_sb_buffer;
2639         }
2640
2641         mutex_lock(&fs_info->chunk_mutex);
2642         ret = btrfs_read_sys_array(tree_root);
2643         mutex_unlock(&fs_info->chunk_mutex);
2644         if (ret) {
2645                 printk(KERN_WARNING "BTRFS: failed to read the system "
2646                        "array on %s\n", sb->s_id);
2647                 goto fail_sb_buffer;
2648         }
2649
2650         generation = btrfs_super_chunk_root_generation(disk_super);
2651
2652         __setup_root(nodesize, sectorsize, stripesize, chunk_root,
2653                      fs_info, BTRFS_CHUNK_TREE_OBJECTID);
2654
2655         chunk_root->node = read_tree_block(chunk_root,
2656                                            btrfs_super_chunk_root(disk_super),
2657                                            generation);
2658         if (!chunk_root->node ||
2659             !test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
2660                 printk(KERN_WARNING "BTRFS: failed to read chunk root on %s\n",
2661                        sb->s_id);
2662                 goto fail_tree_roots;
2663         }
2664         btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
2665         chunk_root->commit_root = btrfs_root_node(chunk_root);
2666
2667         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
2668            btrfs_header_chunk_tree_uuid(chunk_root->node), BTRFS_UUID_SIZE);
2669
2670         ret = btrfs_read_chunk_tree(chunk_root);
2671         if (ret) {
2672                 printk(KERN_WARNING "BTRFS: failed to read chunk tree on %s\n",
2673                        sb->s_id);
2674                 goto fail_tree_roots;
2675         }
2676
2677         /*
2678          * keep the device that is marked to be the target device for the
2679          * dev_replace procedure
2680          */
2681         btrfs_close_extra_devices(fs_info, fs_devices, 0);
2682
2683         if (!fs_devices->latest_bdev) {
2684                 printk(KERN_CRIT "BTRFS: failed to read devices on %s\n",
2685                        sb->s_id);
2686                 goto fail_tree_roots;
2687         }
2688
2689 retry_root_backup:
2690         generation = btrfs_super_generation(disk_super);
2691
2692         tree_root->node = read_tree_block(tree_root,
2693                                           btrfs_super_root(disk_super),
2694                                           generation);
2695         if (!tree_root->node ||
2696             !test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
2697                 printk(KERN_WARNING "BTRFS: failed to read tree root on %s\n",
2698                        sb->s_id);
2699
2700                 goto recovery_tree_root;
2701         }
2702
2703         btrfs_set_root_node(&tree_root->root_item, tree_root->node);
2704         tree_root->commit_root = btrfs_root_node(tree_root);
2705         btrfs_set_root_refs(&tree_root->root_item, 1);
2706
2707         location.objectid = BTRFS_EXTENT_TREE_OBJECTID;
2708         location.type = BTRFS_ROOT_ITEM_KEY;
2709         location.offset = 0;
2710
2711         extent_root = btrfs_read_tree_root(tree_root, &location);
2712         if (IS_ERR(extent_root)) {
2713                 ret = PTR_ERR(extent_root);
2714                 goto recovery_tree_root;
2715         }
2716         set_bit(BTRFS_ROOT_TRACK_DIRTY, &extent_root->state);
2717         fs_info->extent_root = extent_root;
2718
2719         location.objectid = BTRFS_DEV_TREE_OBJECTID;
2720         dev_root = btrfs_read_tree_root(tree_root, &location);
2721         if (IS_ERR(dev_root)) {
2722                 ret = PTR_ERR(dev_root);
2723                 goto recovery_tree_root;
2724         }
2725         set_bit(BTRFS_ROOT_TRACK_DIRTY, &dev_root->state);
2726         fs_info->dev_root = dev_root;
2727         btrfs_init_devices_late(fs_info);
2728
2729         location.objectid = BTRFS_CSUM_TREE_OBJECTID;
2730         csum_root = btrfs_read_tree_root(tree_root, &location);
2731         if (IS_ERR(csum_root)) {
2732                 ret = PTR_ERR(csum_root);
2733                 goto recovery_tree_root;
2734         }
2735         set_bit(BTRFS_ROOT_TRACK_DIRTY, &csum_root->state);
2736         fs_info->csum_root = csum_root;
2737
2738         location.objectid = BTRFS_QUOTA_TREE_OBJECTID;
2739         quota_root = btrfs_read_tree_root(tree_root, &location);
2740         if (!IS_ERR(quota_root)) {
2741                 set_bit(BTRFS_ROOT_TRACK_DIRTY, &quota_root->state);
2742                 fs_info->quota_enabled = 1;
2743                 fs_info->pending_quota_state = 1;
2744                 fs_info->quota_root = quota_root;
2745         }
2746
2747         location.objectid = BTRFS_UUID_TREE_OBJECTID;
2748         uuid_root = btrfs_read_tree_root(tree_root, &location);
2749         if (IS_ERR(uuid_root)) {
2750                 ret = PTR_ERR(uuid_root);
2751                 if (ret != -ENOENT)
2752                         goto recovery_tree_root;
2753                 create_uuid_tree = true;
2754                 check_uuid_tree = false;
2755         } else {
2756                 set_bit(BTRFS_ROOT_TRACK_DIRTY, &uuid_root->state);
2757                 fs_info->uuid_root = uuid_root;
2758                 create_uuid_tree = false;
2759                 check_uuid_tree =
2760                     generation != btrfs_super_uuid_tree_generation(disk_super);
2761         }
2762
2763         fs_info->generation = generation;
2764         fs_info->last_trans_committed = generation;
2765
2766         ret = btrfs_recover_balance(fs_info);
2767         if (ret) {
2768                 printk(KERN_WARNING "BTRFS: failed to recover balance\n");
2769                 goto fail_block_groups;
2770         }
2771
2772         ret = btrfs_init_dev_stats(fs_info);
2773         if (ret) {
2774                 printk(KERN_ERR "BTRFS: failed to init dev_stats: %d\n",
2775                        ret);
2776                 goto fail_block_groups;
2777         }
2778
2779         ret = btrfs_init_dev_replace(fs_info);
2780         if (ret) {
2781                 pr_err("BTRFS: failed to init dev_replace: %d\n", ret);
2782                 goto fail_block_groups;
2783         }
2784
2785         btrfs_close_extra_devices(fs_info, fs_devices, 1);
2786
2787         ret = btrfs_sysfs_add_one(fs_info);
2788         if (ret) {
2789                 pr_err("BTRFS: failed to init sysfs interface: %d\n", ret);
2790                 goto fail_block_groups;
2791         }
2792
2793         ret = btrfs_init_space_info(fs_info);
2794         if (ret) {
2795                 printk(KERN_ERR "BTRFS: Failed to initial space info: %d\n", ret);
2796                 goto fail_sysfs;
2797         }
2798
2799         ret = btrfs_read_block_groups(extent_root);
2800         if (ret) {
2801                 printk(KERN_ERR "BTRFS: Failed to read block groups: %d\n", ret);
2802                 goto fail_sysfs;
2803         }
2804         fs_info->num_tolerated_disk_barrier_failures =
2805                 btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
2806         if (fs_info->fs_devices->missing_devices >
2807              fs_info->num_tolerated_disk_barrier_failures &&
2808             !(sb->s_flags & MS_RDONLY)) {
2809                 printk(KERN_WARNING "BTRFS: "
2810                         "too many missing devices, writeable mount is not allowed\n");
2811                 goto fail_sysfs;
2812         }
2813
2814         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
2815                                                "btrfs-cleaner");
2816         if (IS_ERR(fs_info->cleaner_kthread))
2817                 goto fail_sysfs;
2818
2819         fs_info->transaction_kthread = kthread_run(transaction_kthread,
2820                                                    tree_root,
2821                                                    "btrfs-transaction");
2822         if (IS_ERR(fs_info->transaction_kthread))
2823                 goto fail_cleaner;
2824
2825         if (!btrfs_test_opt(tree_root, SSD) &&
2826             !btrfs_test_opt(tree_root, NOSSD) &&
2827             !fs_info->fs_devices->rotating) {
2828                 printk(KERN_INFO "BTRFS: detected SSD devices, enabling SSD "
2829                        "mode\n");
2830                 btrfs_set_opt(fs_info->mount_opt, SSD);
2831         }
2832
2833         /* Set the real inode map cache flag */
2834         if (btrfs_test_opt(tree_root, CHANGE_INODE_CACHE))
2835                 btrfs_set_opt(tree_root->fs_info->mount_opt, INODE_MAP_CACHE);
2836
2837 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2838         if (btrfs_test_opt(tree_root, CHECK_INTEGRITY)) {
2839                 ret = btrfsic_mount(tree_root, fs_devices,
2840                                     btrfs_test_opt(tree_root,
2841                                         CHECK_INTEGRITY_INCLUDING_EXTENT_DATA) ?
2842                                     1 : 0,
2843                                     fs_info->check_integrity_print_mask);
2844                 if (ret)
2845                         printk(KERN_WARNING "BTRFS: failed to initialize"
2846                                " integrity check module %s\n", sb->s_id);
2847         }
2848 #endif
2849         ret = btrfs_read_qgroup_config(fs_info);
2850         if (ret)
2851                 goto fail_trans_kthread;
2852
2853         /* do not make disk changes in broken FS */
2854         if (btrfs_super_log_root(disk_super) != 0) {
2855                 u64 bytenr = btrfs_super_log_root(disk_super);
2856
2857                 if (fs_devices->rw_devices == 0) {
2858                         printk(KERN_WARNING "BTRFS: log replay required "
2859                                "on RO media\n");
2860                         err = -EIO;
2861                         goto fail_qgroup;
2862                 }
2863
2864                 log_tree_root = btrfs_alloc_root(fs_info);
2865                 if (!log_tree_root) {
2866                         err = -ENOMEM;
2867                         goto fail_qgroup;
2868                 }
2869
2870                 __setup_root(nodesize, sectorsize, stripesize,
2871                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
2872
2873                 log_tree_root->node = read_tree_block(tree_root, bytenr,
2874                                                       generation + 1);
2875                 if (!log_tree_root->node ||
2876                     !extent_buffer_uptodate(log_tree_root->node)) {
2877                         printk(KERN_ERR "BTRFS: failed to read log tree\n");
2878                         free_extent_buffer(log_tree_root->node);
2879                         kfree(log_tree_root);
2880                         goto fail_qgroup;
2881                 }
2882                 /* returns with log_tree_root freed on success */
2883                 ret = btrfs_recover_log_trees(log_tree_root);
2884                 if (ret) {
2885                         btrfs_error(tree_root->fs_info, ret,
2886                                     "Failed to recover log tree");
2887                         free_extent_buffer(log_tree_root->node);
2888                         kfree(log_tree_root);
2889                         goto fail_qgroup;
2890                 }
2891
2892                 if (sb->s_flags & MS_RDONLY) {
2893                         ret = btrfs_commit_super(tree_root);
2894                         if (ret)
2895                                 goto fail_qgroup;
2896                 }
2897         }
2898
2899         ret = btrfs_find_orphan_roots(tree_root);
2900         if (ret)
2901                 goto fail_qgroup;
2902
2903         if (!(sb->s_flags & MS_RDONLY)) {
2904                 ret = btrfs_cleanup_fs_roots(fs_info);
2905                 if (ret)
2906                         goto fail_qgroup;
2907
2908                 mutex_lock(&fs_info->cleaner_mutex);
2909                 ret = btrfs_recover_relocation(tree_root);
2910                 mutex_unlock(&fs_info->cleaner_mutex);
2911                 if (ret < 0) {
2912                         printk(KERN_WARNING
2913                                "BTRFS: failed to recover relocation\n");
2914                         err = -EINVAL;
2915                         goto fail_qgroup;
2916                 }
2917         }
2918
2919         location.objectid = BTRFS_FS_TREE_OBJECTID;
2920         location.type = BTRFS_ROOT_ITEM_KEY;
2921         location.offset = 0;
2922
2923         fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
2924         if (IS_ERR(fs_info->fs_root)) {
2925                 err = PTR_ERR(fs_info->fs_root);
2926                 goto fail_qgroup;
2927         }
2928
2929         if (sb->s_flags & MS_RDONLY)
2930                 return 0;
2931
2932         down_read(&fs_info->cleanup_work_sem);
2933         if ((ret = btrfs_orphan_cleanup(fs_info->fs_root)) ||
2934             (ret = btrfs_orphan_cleanup(fs_info->tree_root))) {
2935                 up_read(&fs_info->cleanup_work_sem);
2936                 close_ctree(tree_root);
2937                 return ret;
2938         }
2939         up_read(&fs_info->cleanup_work_sem);
2940
2941         ret = btrfs_resume_balance_async(fs_info);
2942         if (ret) {
2943                 printk(KERN_WARNING "BTRFS: failed to resume balance\n");
2944                 close_ctree(tree_root);
2945                 return ret;
2946         }
2947
2948         ret = btrfs_resume_dev_replace_async(fs_info);
2949         if (ret) {
2950                 pr_warn("BTRFS: failed to resume dev_replace\n");
2951                 close_ctree(tree_root);
2952                 return ret;
2953         }
2954
2955         btrfs_qgroup_rescan_resume(fs_info);
2956
2957         if (create_uuid_tree) {
2958                 pr_info("BTRFS: creating UUID tree\n");
2959                 ret = btrfs_create_uuid_tree(fs_info);
2960                 if (ret) {
2961                         pr_warn("BTRFS: failed to create the UUID tree %d\n",
2962                                 ret);
2963                         close_ctree(tree_root);
2964                         return ret;
2965                 }
2966         } else if (check_uuid_tree ||
2967                    btrfs_test_opt(tree_root, RESCAN_UUID_TREE)) {
2968                 pr_info("BTRFS: checking UUID tree\n");
2969                 ret = btrfs_check_uuid_tree(fs_info);
2970                 if (ret) {
2971                         pr_warn("BTRFS: failed to check the UUID tree %d\n",
2972                                 ret);
2973                         close_ctree(tree_root);
2974                         return ret;
2975                 }
2976         } else {
2977                 fs_info->update_uuid_tree_gen = 1;
2978         }
2979
2980         fs_info->open = 1;
2981
2982         return 0;
2983
2984 fail_qgroup:
2985         btrfs_free_qgroup_config(fs_info);
2986 fail_trans_kthread:
2987         kthread_stop(fs_info->transaction_kthread);
2988         btrfs_cleanup_transaction(fs_info->tree_root);
2989         btrfs_free_fs_roots(fs_info);
2990 fail_cleaner:
2991         kthread_stop(fs_info->cleaner_kthread);
2992
2993         /*
2994          * make sure we're done with the btree inode before we stop our
2995          * kthreads
2996          */
2997         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
2998
2999 fail_sysfs:
3000         btrfs_sysfs_remove_one(fs_info);
3001
3002 fail_block_groups:
3003         btrfs_put_block_group_cache(fs_info);
3004         btrfs_free_block_groups(fs_info);
3005
3006 fail_tree_roots:
3007         free_root_pointers(fs_info, 1);
3008         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
3009
3010 fail_sb_buffer:
3011         btrfs_stop_all_workers(fs_info);
3012 fail_alloc:
3013 fail_iput:
3014         btrfs_mapping_tree_free(&fs_info->mapping_tree);
3015
3016         iput(fs_info->btree_inode);
3017 fail_bio_counter:
3018         percpu_counter_destroy(&fs_info->bio_counter);
3019 fail_delalloc_bytes:
3020         percpu_counter_destroy(&fs_info->delalloc_bytes);
3021 fail_dirty_metadata_bytes:
3022         percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
3023 fail_bdi:
3024         bdi_destroy(&fs_info->bdi);
3025 fail_srcu:
3026         cleanup_srcu_struct(&fs_info->subvol_srcu);
3027 fail:
3028         btrfs_free_stripe_hash_table(fs_info);
3029         btrfs_close_devices(fs_info->fs_devices);
3030         return err;
3031
3032 recovery_tree_root:
3033         if (!btrfs_test_opt(tree_root, RECOVERY))
3034                 goto fail_tree_roots;
3035
3036         free_root_pointers(fs_info, 0);
3037
3038         /* don't use the log in recovery mode, it won't be valid */
3039         btrfs_set_super_log_root(disk_super, 0);
3040
3041         /* we can't trust the free space cache either */
3042         btrfs_set_opt(fs_info->mount_opt, CLEAR_CACHE);
3043
3044         ret = next_root_backup(fs_info, fs_info->super_copy,
3045                                &num_backups_tried, &backup_index);
3046         if (ret == -1)
3047                 goto fail_block_groups;
3048         goto retry_root_backup;
3049 }
3050
3051 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
3052 {
3053         if (uptodate) {
3054                 set_buffer_uptodate(bh);
3055         } else {
3056                 struct btrfs_device *device = (struct btrfs_device *)
3057                         bh->b_private;
3058
3059                 printk_ratelimited_in_rcu(KERN_WARNING "BTRFS: lost page write due to "
3060                                           "I/O error on %s\n",
3061                                           rcu_str_deref(device->name));
3062                 /* note, we dont' set_buffer_write_io_error because we have
3063                  * our own ways of dealing with the IO errors
3064                  */
3065                 clear_buffer_uptodate(bh);
3066                 btrfs_dev_stat_inc_and_print(device, BTRFS_DEV_STAT_WRITE_ERRS);
3067         }
3068         unlock_buffer(bh);
3069         put_bh(bh);
3070 }
3071
3072 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
3073 {
3074         struct buffer_head *bh;
3075         struct buffer_head *latest = NULL;
3076         struct btrfs_super_block *super;
3077         int i;
3078         u64 transid = 0;
3079         u64 bytenr;
3080
3081         /* we would like to check all the supers, but that would make
3082          * a btrfs mount succeed after a mkfs from a different FS.
3083          * So, we need to add a special mount option to scan for
3084          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
3085          */
3086         for (i = 0; i < 1; i++) {
3087                 bytenr = btrfs_sb_offset(i);
3088                 if (bytenr + BTRFS_SUPER_INFO_SIZE >=
3089                                         i_size_read(bdev->bd_inode))
3090                         break;
3091                 bh = __bread(bdev, bytenr / 4096,
3092                                         BTRFS_SUPER_INFO_SIZE);
3093                 if (!bh)
3094                         continue;
3095
3096                 super = (struct btrfs_super_block *)bh->b_data;
3097                 if (btrfs_super_bytenr(super) != bytenr ||
3098                     btrfs_super_magic(super) != BTRFS_MAGIC) {
3099                         brelse(bh);
3100                         continue;
3101                 }
3102
3103                 if (!latest || btrfs_super_generation(super) > transid) {
3104                         brelse(latest);
3105                         latest = bh;
3106                         transid = btrfs_super_generation(super);
3107                 } else {
3108                         brelse(bh);
3109                 }
3110         }
3111         return latest;
3112 }
3113
3114 /*
3115  * this should be called twice, once with wait == 0 and
3116  * once with wait == 1.  When wait == 0 is done, all the buffer heads
3117  * we write are pinned.
3118  *
3119  * They are released when wait == 1 is done.
3120  * max_mirrors must be the same for both runs, and it indicates how
3121  * many supers on this one device should be written.
3122  *
3123  * max_mirrors == 0 means to write them all.
3124  */
3125 static int write_dev_supers(struct btrfs_device *device,
3126                             struct btrfs_super_block *sb,
3127                             int do_barriers, int wait, int max_mirrors)
3128 {
3129         struct buffer_head *bh;
3130         int i;
3131         int ret;
3132         int errors = 0;
3133         u32 crc;
3134         u64 bytenr;
3135
3136         if (max_mirrors == 0)
3137                 max_mirrors = BTRFS_SUPER_MIRROR_MAX;
3138
3139         for (i = 0; i < max_mirrors; i++) {
3140                 bytenr = btrfs_sb_offset(i);
3141                 if (bytenr + BTRFS_SUPER_INFO_SIZE >=
3142                     device->commit_total_bytes)
3143                         break;
3144
3145                 if (wait) {
3146                         bh = __find_get_block(device->bdev, bytenr / 4096,
3147                                               BTRFS_SUPER_INFO_SIZE);
3148                         if (!bh) {
3149                                 errors++;
3150                                 continue;
3151                         }
3152                         wait_on_buffer(bh);
3153                         if (!buffer_uptodate(bh))
3154                                 errors++;
3155
3156                         /* drop our reference */
3157                         brelse(bh);
3158
3159                         /* drop the reference from the wait == 0 run */
3160                         brelse(bh);
3161                         continue;
3162                 } else {
3163                         btrfs_set_super_bytenr(sb, bytenr);
3164
3165                         crc = ~(u32)0;
3166                         crc = btrfs_csum_data((char *)sb +
3167                                               BTRFS_CSUM_SIZE, crc,
3168                                               BTRFS_SUPER_INFO_SIZE -
3169                                               BTRFS_CSUM_SIZE);
3170                         btrfs_csum_final(crc, sb->csum);
3171
3172                         /*
3173                          * one reference for us, and we leave it for the
3174                          * caller
3175                          */
3176                         bh = __getblk(device->bdev, bytenr / 4096,
3177                                       BTRFS_SUPER_INFO_SIZE);
3178                         if (!bh) {
3179                                 printk(KERN_ERR "BTRFS: couldn't get super "
3180                                        "buffer head for bytenr %Lu\n", bytenr);
3181                                 errors++;
3182                                 continue;
3183                         }
3184
3185                         memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
3186
3187                         /* one reference for submit_bh */
3188                         get_bh(bh);
3189
3190                         set_buffer_uptodate(bh);
3191                         lock_buffer(bh);
3192                         bh->b_end_io = btrfs_end_buffer_write_sync;
3193                         bh->b_private = device;
3194                 }
3195
3196                 /*
3197                  * we fua the first super.  The others we allow
3198                  * to go down lazy.
3199                  */
3200                 if (i == 0)
3201                         ret = btrfsic_submit_bh(WRITE_FUA, bh);
3202                 else
3203                         ret = btrfsic_submit_bh(WRITE_SYNC, bh);
3204                 if (ret)
3205                         errors++;
3206         }
3207         return errors < i ? 0 : -1;
3208 }
3209
3210 /*
3211  * endio for the write_dev_flush, this will wake anyone waiting
3212  * for the barrier when it is done
3213  */
3214 static void btrfs_end_empty_barrier(struct bio *bio, int err)
3215 {
3216         if (err) {
3217                 if (err == -EOPNOTSUPP)
3218                         set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
3219                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
3220         }
3221         if (bio->bi_private)
3222                 complete(bio->bi_private);
3223         bio_put(bio);
3224 }
3225
3226 /*
3227  * trigger flushes for one the devices.  If you pass wait == 0, the flushes are
3228  * sent down.  With wait == 1, it waits for the previous flush.
3229  *
3230  * any device where the flush fails with eopnotsupp are flagged as not-barrier
3231  * capable
3232  */
3233 static int write_dev_flush(struct btrfs_device *device, int wait)
3234 {
3235         struct bio *bio;
3236         int ret = 0;
3237
3238         if (device->nobarriers)
3239                 return 0;
3240
3241         if (wait) {
3242                 bio = device->flush_bio;
3243                 if (!bio)
3244                         return 0;
3245
3246                 wait_for_completion(&device->flush_wait);
3247
3248                 if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
3249                         printk_in_rcu("BTRFS: disabling barriers on dev %s\n",
3250                                       rcu_str_deref(device->name));
3251                         device->nobarriers = 1;
3252                 } else if (!bio_flagged(bio, BIO_UPTODATE)) {
3253                         ret = -EIO;
3254                         btrfs_dev_stat_inc_and_print(device,
3255                                 BTRFS_DEV_STAT_FLUSH_ERRS);
3256                 }
3257
3258                 /* drop the reference from the wait == 0 run */
3259                 bio_put(bio);
3260                 device->flush_bio = NULL;
3261
3262                 return ret;
3263         }
3264
3265         /*
3266          * one reference for us, and we leave it for the
3267          * caller
3268          */
3269         device->flush_bio = NULL;
3270         bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
3271         if (!bio)
3272                 return -ENOMEM;
3273
3274         bio->bi_end_io = btrfs_end_empty_barrier;
3275         bio->bi_bdev = device->bdev;
3276         init_completion(&device->flush_wait);
3277         bio->bi_private = &device->flush_wait;
3278         device->flush_bio = bio;
3279
3280         bio_get(bio);
3281         btrfsic_submit_bio(WRITE_FLUSH, bio);
3282
3283         return 0;
3284 }
3285
3286 /*
3287  * send an empty flush down to each device in parallel,
3288  * then wait for them
3289  */
3290 static int barrier_all_devices(struct btrfs_fs_info *info)
3291 {
3292         struct list_head *head;
3293         struct btrfs_device *dev;
3294         int errors_send = 0;
3295         int errors_wait = 0;
3296         int ret;
3297
3298         /* send down all the barriers */
3299         head = &info->fs_devices->devices;
3300         list_for_each_entry_rcu(dev, head, dev_list) {
3301                 if (dev->missing)
3302                         continue;
3303                 if (!dev->bdev) {
3304                         errors_send++;
3305                         continue;
3306                 }
3307                 if (!dev->in_fs_metadata || !dev->writeable)
3308                         continue;
3309
3310                 ret = write_dev_flush(dev, 0);
3311                 if (ret)
3312                         errors_send++;
3313         }
3314
3315         /* wait for all the barriers */
3316         list_for_each_entry_rcu(dev, head, dev_list) {
3317                 if (dev->missing)
3318                         continue;
3319                 if (!dev->bdev) {
3320                         errors_wait++;
3321                         continue;
3322                 }
3323                 if (!dev->in_fs_metadata || !dev->writeable)
3324                         continue;
3325
3326                 ret = write_dev_flush(dev, 1);
3327                 if (ret)
3328                         errors_wait++;
3329         }
3330         if (errors_send > info->num_tolerated_disk_barrier_failures ||
3331             errors_wait > info->num_tolerated_disk_barrier_failures)
3332                 return -EIO;
3333         return 0;
3334 }
3335
3336 int btrfs_calc_num_tolerated_disk_barrier_failures(
3337         struct btrfs_fs_info *fs_info)
3338 {
3339         struct btrfs_ioctl_space_info space;
3340         struct btrfs_space_info *sinfo;
3341         u64 types[] = {BTRFS_BLOCK_GROUP_DATA,
3342                        BTRFS_BLOCK_GROUP_SYSTEM,
3343                        BTRFS_BLOCK_GROUP_METADATA,
3344                        BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
3345         int num_types = 4;
3346         int i;
3347         int c;
3348         int num_tolerated_disk_barrier_failures =
3349                 (int)fs_info->fs_devices->num_devices;
3350
3351         for (i = 0; i < num_types; i++) {
3352                 struct btrfs_space_info *tmp;
3353
3354                 sinfo = NULL;
3355                 rcu_read_lock();
3356                 list_for_each_entry_rcu(tmp, &fs_info->space_info, list) {
3357                         if (tmp->flags == types[i]) {
3358                                 sinfo = tmp;
3359                                 break;
3360                         }
3361                 }
3362                 rcu_read_unlock();
3363
3364                 if (!sinfo)
3365                         continue;
3366
3367                 down_read(&sinfo->groups_sem);
3368                 for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3369                         if (!list_empty(&sinfo->block_groups[c])) {
3370                                 u64 flags;
3371
3372                                 btrfs_get_block_group_info(
3373                                         &sinfo->block_groups[c], &space);
3374                                 if (space.total_bytes == 0 ||
3375                                     space.used_bytes == 0)
3376                                         continue;
3377                                 flags = space.flags;
3378                                 /*
3379                                  * return
3380                                  * 0: if dup, single or RAID0 is configured for
3381                                  *    any of metadata, system or data, else
3382                                  * 1: if RAID5 is configured, or if RAID1 or
3383                                  *    RAID10 is configured and only two mirrors
3384                                  *    are used, else
3385                                  * 2: if RAID6 is configured, else
3386                                  * num_mirrors - 1: if RAID1 or RAID10 is
3387                                  *                  configured and more than
3388                                  *                  2 mirrors are used.
3389                                  */
3390                                 if (num_tolerated_disk_barrier_failures > 0 &&
3391                                     ((flags & (BTRFS_BLOCK_GROUP_DUP |
3392                                                BTRFS_BLOCK_GROUP_RAID0)) ||
3393                                      ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK)
3394                                       == 0)))
3395                                         num_tolerated_disk_barrier_failures = 0;
3396                                 else if (num_tolerated_disk_barrier_failures > 1) {
3397                                         if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3398                                             BTRFS_BLOCK_GROUP_RAID5 |
3399                                             BTRFS_BLOCK_GROUP_RAID10)) {
3400                                                 num_tolerated_disk_barrier_failures = 1;
3401                                         } else if (flags &
3402                                                    BTRFS_BLOCK_GROUP_RAID6) {
3403                                                 num_tolerated_disk_barrier_failures = 2;
3404                                         }
3405                                 }
3406                         }
3407                 }
3408                 up_read(&sinfo->groups_sem);
3409         }
3410
3411         return num_tolerated_disk_barrier_failures;
3412 }
3413
3414 static int write_all_supers(struct btrfs_root *root, int max_mirrors)
3415 {
3416         struct list_head *head;
3417         struct btrfs_device *dev;
3418         struct btrfs_super_block *sb;
3419         struct btrfs_dev_item *dev_item;
3420         int ret;
3421         int do_barriers;
3422         int max_errors;
3423         int total_errors = 0;
3424         u64 flags;
3425
3426         do_barriers = !btrfs_test_opt(root, NOBARRIER);
3427         backup_super_roots(root->fs_info);
3428
3429         sb = root->fs_info->super_for_commit;
3430         dev_item = &sb->dev_item;
3431
3432         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
3433         head = &root->fs_info->fs_devices->devices;
3434         max_errors = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
3435
3436         if (do_barriers) {
3437                 ret = barrier_all_devices(root->fs_info);
3438                 if (ret) {
3439                         mutex_unlock(
3440                                 &root->fs_info->fs_devices->device_list_mutex);
3441                         btrfs_error(root->fs_info, ret,
3442                                     "errors while submitting device barriers.");
3443                         return ret;
3444                 }
3445         }
3446
3447         list_for_each_entry_rcu(dev, head, dev_list) {
3448                 if (!dev->bdev) {
3449                         total_errors++;
3450                         continue;
3451                 }
3452                 if (!dev->in_fs_metadata || !dev->writeable)
3453                         continue;
3454
3455                 btrfs_set_stack_device_generation(dev_item, 0);
3456                 btrfs_set_stack_device_type(dev_item, dev->type);
3457                 btrfs_set_stack_device_id(dev_item, dev->devid);
3458                 btrfs_set_stack_device_total_bytes(dev_item,
3459                                                    dev->commit_total_bytes);
3460                 btrfs_set_stack_device_bytes_used(dev_item,
3461                                                   dev->commit_bytes_used);
3462                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
3463                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
3464                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
3465                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
3466                 memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
3467
3468                 flags = btrfs_super_flags(sb);
3469                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
3470
3471                 ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
3472                 if (ret)
3473                         total_errors++;
3474         }
3475         if (total_errors > max_errors) {
3476                 btrfs_err(root->fs_info, "%d errors while writing supers",
3477                        total_errors);
3478                 mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
3479
3480                 /* FUA is masked off if unsupported and can't be the reason */
3481                 btrfs_error(root->fs_info, -EIO,
3482                             "%d errors while writing supers", total_errors);
3483                 return -EIO;
3484         }
3485
3486         total_errors = 0;
3487         list_for_each_entry_rcu(dev, head, dev_list) {
3488                 if (!dev->bdev)
3489                         continue;
3490                 if (!dev->in_fs_metadata || !dev->writeable)
3491                         continue;
3492
3493                 ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
3494                 if (ret)
3495                         total_errors++;
3496         }
3497         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
3498         if (total_errors > max_errors) {
3499                 btrfs_error(root->fs_info, -EIO,
3500                             "%d errors while writing supers", total_errors);
3501                 return -EIO;
3502         }
3503         return 0;
3504 }
3505
3506 int write_ctree_super(struct btrfs_trans_handle *trans,
3507                       struct btrfs_root *root, int max_mirrors)
3508 {
3509         return write_all_supers(root, max_mirrors);
3510 }
3511
3512 /* Drop a fs root from the radix tree and free it. */
3513 void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info,
3514                                   struct btrfs_root *root)
3515 {
3516         spin_lock(&fs_info->fs_roots_radix_lock);
3517         radix_tree_delete(&fs_info->fs_roots_radix,
3518                           (unsigned long)root->root_key.objectid);
3519         spin_unlock(&fs_info->fs_roots_radix_lock);
3520
3521         if (btrfs_root_refs(&root->root_item) == 0)
3522                 synchronize_srcu(&fs_info->subvol_srcu);
3523
3524         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
3525                 btrfs_free_log(NULL, root);
3526
3527         if (root->free_ino_pinned)
3528                 __btrfs_remove_free_space_cache(root->free_ino_pinned);
3529         if (root->free_ino_ctl)
3530                 __btrfs_remove_free_space_cache(root->free_ino_ctl);
3531         free_fs_root(root);
3532 }
3533
3534 static void free_fs_root(struct btrfs_root *root)
3535 {
3536         iput(root->ino_cache_inode);
3537         WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
3538         btrfs_free_block_rsv(root, root->orphan_block_rsv);
3539         root->orphan_block_rsv = NULL;
3540         if (root->anon_dev)
3541                 free_anon_bdev(root->anon_dev);
3542         if (root->subv_writers)
3543                 btrfs_free_subvolume_writers(root->subv_writers);
3544         free_extent_buffer(root->node);
3545         free_extent_buffer(root->commit_root);
3546         kfree(root->free_ino_ctl);
3547         kfree(root->free_ino_pinned);
3548         kfree(root->name);
3549         btrfs_put_fs_root(root);
3550 }
3551
3552 void btrfs_free_fs_root(struct btrfs_root *root)
3553 {
3554         free_fs_root(root);
3555 }
3556
3557 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
3558 {
3559         u64 root_objectid = 0;
3560         struct btrfs_root *gang[8];
3561         int i = 0;
3562         int err = 0;
3563         unsigned int ret = 0;
3564         int index;
3565
3566         while (1) {
3567                 index = srcu_read_lock(&fs_info->subvol_srcu);
3568                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
3569                                              (void **)gang, root_objectid,
3570                                              ARRAY_SIZE(gang));
3571                 if (!ret) {
3572                         srcu_read_unlock(&fs_info->subvol_srcu, index);
3573                         break;
3574                 }
3575                 root_objectid = gang[ret - 1]->root_key.objectid + 1;
3576
3577                 for (i = 0; i < ret; i++) {
3578                         /* Avoid to grab roots in dead_roots */
3579                         if (btrfs_root_refs(&gang[i]->root_item) == 0) {
3580                                 gang[i] = NULL;
3581                                 continue;
3582                         }
3583                         /* grab all the search result for later use */
3584                         gang[i] = btrfs_grab_fs_root(gang[i]);
3585                 }
3586                 srcu_read_unlock(&fs_info->subvol_srcu, index);
3587
3588                 for (i = 0; i < ret; i++) {
3589                         if (!gang[i])
3590                                 continue;
3591                         root_objectid = gang[i]->root_key.objectid;
3592                         err = btrfs_orphan_cleanup(gang[i]);
3593                         if (err)
3594                                 break;
3595                         btrfs_put_fs_root(gang[i]);
3596                 }
3597                 root_objectid++;
3598         }
3599
3600         /* release the uncleaned roots due to error */
3601         for (; i < ret; i++) {
3602                 if (gang[i])
3603                         btrfs_put_fs_root(gang[i]);
3604         }
3605         return err;
3606 }
3607
3608 int btrfs_commit_super(struct btrfs_root *root)
3609 {
3610         struct btrfs_trans_handle *trans;
3611
3612         mutex_lock(&root->fs_info->cleaner_mutex);
3613         btrfs_run_delayed_iputs(root);
3614         mutex_unlock(&root->fs_info->cleaner_mutex);
3615         wake_up_process(root->fs_info->cleaner_kthread);
3616
3617         /* wait until ongoing cleanup work done */
3618         down_write(&root->fs_info->cleanup_work_sem);
3619         up_write(&root->fs_info->cleanup_work_sem);
3620
3621         trans = btrfs_join_transaction(root);
3622         if (IS_ERR(trans))
3623                 return PTR_ERR(trans);
3624         return btrfs_commit_transaction(trans, root);
3625 }
3626
3627 void close_ctree(struct btrfs_root *root)
3628 {
3629         struct btrfs_fs_info *fs_info = root->fs_info;
3630         int ret;
3631
3632         fs_info->closing = 1;
3633         smp_mb();
3634
3635         /* wait for the uuid_scan task to finish */
3636         down(&fs_info->uuid_tree_rescan_sem);
3637         /* avoid complains from lockdep et al., set sem back to initial state */
3638         up(&fs_info->uuid_tree_rescan_sem);
3639
3640         /* pause restriper - we want to resume on mount */
3641         btrfs_pause_balance(fs_info);
3642
3643         btrfs_dev_replace_suspend_for_unmount(fs_info);
3644
3645         btrfs_scrub_cancel(fs_info);
3646
3647         /* wait for any defraggers to finish */
3648         wait_event(fs_info->transaction_wait,
3649                    (atomic_read(&fs_info->defrag_running) == 0));
3650
3651         /* clear out the rbtree of defraggable inodes */
3652         btrfs_cleanup_defrag_inodes(fs_info);
3653
3654         cancel_work_sync(&fs_info->async_reclaim_work);
3655
3656         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
3657                 ret = btrfs_commit_super(root);
3658                 if (ret)
3659                         btrfs_err(root->fs_info, "commit super ret %d", ret);
3660         }
3661
3662         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
3663                 btrfs_error_commit_super(root);
3664
3665         kthread_stop(fs_info->transaction_kthread);
3666         kthread_stop(fs_info->cleaner_kthread);
3667
3668         fs_info->closing = 2;
3669         smp_mb();
3670
3671         btrfs_free_qgroup_config(root->fs_info);
3672
3673         if (percpu_counter_sum(&fs_info->delalloc_bytes)) {
3674                 btrfs_info(root->fs_info, "at unmount delalloc count %lld",
3675                        percpu_counter_sum(&fs_info->delalloc_bytes));
3676         }
3677
3678         btrfs_sysfs_remove_one(fs_info);
3679
3680         btrfs_free_fs_roots(fs_info);
3681
3682         btrfs_put_block_group_cache(fs_info);
3683
3684         btrfs_free_block_groups(fs_info);
3685
3686         /*
3687          * we must make sure there is not any read request to
3688          * submit after we stopping all workers.
3689          */
3690         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
3691         btrfs_stop_all_workers(fs_info);
3692
3693         fs_info->open = 0;
3694         free_root_pointers(fs_info, 1);
3695
3696         iput(fs_info->btree_inode);
3697
3698 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
3699         if (btrfs_test_opt(root, CHECK_INTEGRITY))
3700                 btrfsic_unmount(root, fs_info->fs_devices);
3701 #endif
3702
3703         btrfs_close_devices(fs_info->fs_devices);
3704         btrfs_mapping_tree_free(&fs_info->mapping_tree);
3705
3706         percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
3707         percpu_counter_destroy(&fs_info->delalloc_bytes);
3708         percpu_counter_destroy(&fs_info->bio_counter);
3709         bdi_destroy(&fs_info->bdi);
3710         cleanup_srcu_struct(&fs_info->subvol_srcu);
3711
3712         btrfs_free_stripe_hash_table(fs_info);
3713
3714         btrfs_free_block_rsv(root, root->orphan_block_rsv);
3715         root->orphan_block_rsv = NULL;
3716 }
3717
3718 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
3719                           int atomic)
3720 {
3721         int ret;
3722         struct inode *btree_inode = buf->pages[0]->mapping->host;
3723
3724         ret = extent_buffer_uptodate(buf);
3725         if (!ret)
3726                 return ret;
3727
3728         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
3729                                     parent_transid, atomic);
3730         if (ret == -EAGAIN)
3731                 return ret;
3732         return !ret;
3733 }
3734
3735 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
3736 {
3737         return set_extent_buffer_uptodate(buf);
3738 }
3739
3740 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
3741 {
3742         struct btrfs_root *root;
3743         u64 transid = btrfs_header_generation(buf);
3744         int was_dirty;
3745
3746 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3747         /*
3748          * This is a fast path so only do this check if we have sanity tests
3749          * enabled.  Normal people shouldn't be marking dummy buffers as dirty
3750          * outside of the sanity tests.
3751          */
3752         if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &buf->bflags)))
3753                 return;
3754 #endif
3755         root = BTRFS_I(buf->pages[0]->mapping->host)->root;
3756         btrfs_assert_tree_locked(buf);
3757         if (transid != root->fs_info->generation)
3758                 WARN(1, KERN_CRIT "btrfs transid mismatch buffer %llu, "
3759                        "found %llu running %llu\n",
3760                         buf->start, transid, root->fs_info->generation);
3761         was_dirty = set_extent_buffer_dirty(buf);
3762         if (!was_dirty)
3763                 __percpu_counter_add(&root->fs_info->dirty_metadata_bytes,
3764                                      buf->len,
3765                                      root->fs_info->dirty_metadata_batch);
3766 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
3767         if (btrfs_header_level(buf) == 0 && check_leaf(root, buf)) {
3768                 btrfs_print_leaf(root, buf);
3769                 ASSERT(0);
3770         }
3771 #endif
3772 }
3773
3774 static void __btrfs_btree_balance_dirty(struct btrfs_root *root,
3775                                         int flush_delayed)
3776 {
3777         /*
3778          * looks as though older kernels can get into trouble with
3779          * this code, they end up stuck in balance_dirty_pages forever
3780          */
3781         int ret;
3782
3783         if (current->flags & PF_MEMALLOC)
3784                 return;
3785
3786         if (flush_delayed)
3787                 btrfs_balance_delayed_items(root);
3788
3789         ret = percpu_counter_compare(&root->fs_info->dirty_metadata_bytes,
3790                                      BTRFS_DIRTY_METADATA_THRESH);
3791         if (ret > 0) {
3792                 balance_dirty_pages_ratelimited(
3793                                    root->fs_info->btree_inode->i_mapping);
3794         }
3795         return;
3796 }
3797
3798 void btrfs_btree_balance_dirty(struct btrfs_root *root)
3799 {
3800         __btrfs_btree_balance_dirty(root, 1);
3801 }
3802
3803 void btrfs_btree_balance_dirty_nodelay(struct btrfs_root *root)
3804 {
3805         __btrfs_btree_balance_dirty(root, 0);
3806 }
3807
3808 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
3809 {
3810         struct btrfs_root *root = BTRFS_I(buf->pages[0]->mapping->host)->root;
3811         return btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
3812 }
3813
3814 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
3815                               int read_only)
3816 {
3817         struct btrfs_super_block *sb = fs_info->super_copy;
3818         int ret = 0;
3819
3820         if (sb->root_level > BTRFS_MAX_LEVEL) {
3821                 printk(KERN_ERR "BTRFS: tree_root level too big: %d > %d\n",
3822                                 sb->root_level, BTRFS_MAX_LEVEL);
3823                 ret = -EINVAL;
3824         }
3825         if (sb->chunk_root_level > BTRFS_MAX_LEVEL) {
3826                 printk(KERN_ERR "BTRFS: chunk_root level too big: %d > %d\n",
3827                                 sb->chunk_root_level, BTRFS_MAX_LEVEL);
3828                 ret = -EINVAL;
3829         }
3830         if (sb->log_root_level > BTRFS_MAX_LEVEL) {
3831                 printk(KERN_ERR "BTRFS: log_root level too big: %d > %d\n",
3832                                 sb->log_root_level, BTRFS_MAX_LEVEL);
3833                 ret = -EINVAL;
3834         }
3835
3836         /*
3837          * The common minimum, we don't know if we can trust the nodesize/sectorsize
3838          * items yet, they'll be verified later. Issue just a warning.
3839          */
3840         if (!IS_ALIGNED(sb->root, 4096))
3841                 printk(KERN_WARNING "BTRFS: tree_root block unaligned: %llu\n",
3842                                 sb->root);
3843         if (!IS_ALIGNED(sb->chunk_root, 4096))
3844                 printk(KERN_WARNING "BTRFS: tree_root block unaligned: %llu\n",
3845                                 sb->chunk_root);
3846         if (!IS_ALIGNED(sb->log_root, 4096))
3847                 printk(KERN_WARNING "BTRFS: tree_root block unaligned: %llu\n",
3848                                 sb->log_root);
3849
3850         if (memcmp(fs_info->fsid, sb->dev_item.fsid, BTRFS_UUID_SIZE) != 0) {
3851                 printk(KERN_ERR "BTRFS: dev_item UUID does not match fsid: %pU != %pU\n",
3852                                 fs_info->fsid, sb->dev_item.fsid);
3853                 ret = -EINVAL;
3854         }
3855
3856         /*
3857          * Hint to catch really bogus numbers, bitflips or so, more exact checks are
3858          * done later
3859          */
3860         if (sb->num_devices > (1UL << 31))
3861                 printk(KERN_WARNING "BTRFS: suspicious number of devices: %llu\n",
3862                                 sb->num_devices);
3863
3864         if (sb->bytenr != BTRFS_SUPER_INFO_OFFSET) {
3865                 printk(KERN_ERR "BTRFS: super offset mismatch %llu != %u\n",
3866                                 sb->bytenr, BTRFS_SUPER_INFO_OFFSET);
3867                 ret = -EINVAL;
3868         }
3869
3870         /*
3871          * The generation is a global counter, we'll trust it more than the others
3872          * but it's still possible that it's the one that's wrong.
3873          */
3874         if (sb->generation < sb->chunk_root_generation)
3875                 printk(KERN_WARNING
3876                         "BTRFS: suspicious: generation < chunk_root_generation: %llu < %llu\n",
3877                         sb->generation, sb->chunk_root_generation);
3878         if (sb->generation < sb->cache_generation && sb->cache_generation != (u64)-1)
3879                 printk(KERN_WARNING
3880                         "BTRFS: suspicious: generation < cache_generation: %llu < %llu\n",
3881                         sb->generation, sb->cache_generation);
3882
3883         return ret;
3884 }
3885
3886 static void btrfs_error_commit_super(struct btrfs_root *root)
3887 {
3888         mutex_lock(&root->fs_info->cleaner_mutex);
3889         btrfs_run_delayed_iputs(root);
3890         mutex_unlock(&root->fs_info->cleaner_mutex);
3891
3892         down_write(&root->fs_info->cleanup_work_sem);
3893         up_write(&root->fs_info->cleanup_work_sem);
3894
3895         /* cleanup FS via transaction */
3896         btrfs_cleanup_transaction(root);
3897 }
3898
3899 static void btrfs_destroy_ordered_extents(struct btrfs_root *root)
3900 {
3901         struct btrfs_ordered_extent *ordered;
3902
3903         spin_lock(&root->ordered_extent_lock);
3904         /*
3905          * This will just short circuit the ordered completion stuff which will
3906          * make sure the ordered extent gets properly cleaned up.
3907          */
3908         list_for_each_entry(ordered, &root->ordered_extents,
3909                             root_extent_list)
3910                 set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
3911         spin_unlock(&root->ordered_extent_lock);
3912 }
3913
3914 static void btrfs_destroy_all_ordered_extents(struct btrfs_fs_info *fs_info)
3915 {
3916         struct btrfs_root *root;
3917         struct list_head splice;
3918
3919         INIT_LIST_HEAD(&splice);
3920
3921         spin_lock(&fs_info->ordered_root_lock);
3922         list_splice_init(&fs_info->ordered_roots, &splice);
3923         while (!list_empty(&splice)) {
3924                 root = list_first_entry(&splice, struct btrfs_root,
3925                                         ordered_root);
3926                 list_move_tail(&root->ordered_root,
3927                                &fs_info->ordered_roots);
3928
3929                 spin_unlock(&fs_info->ordered_root_lock);
3930                 btrfs_destroy_ordered_extents(root);
3931
3932                 cond_resched();
3933                 spin_lock(&fs_info->ordered_root_lock);
3934         }
3935         spin_unlock(&fs_info->ordered_root_lock);
3936 }
3937
3938 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
3939                                       struct btrfs_root *root)
3940 {
3941         struct rb_node *node;
3942         struct btrfs_delayed_ref_root *delayed_refs;
3943         struct btrfs_delayed_ref_node *ref;
3944         int ret = 0;
3945
3946         delayed_refs = &trans->delayed_refs;
3947
3948         spin_lock(&delayed_refs->lock);
3949         if (atomic_read(&delayed_refs->num_entries) == 0) {
3950                 spin_unlock(&delayed_refs->lock);
3951                 btrfs_info(root->fs_info, "delayed_refs has NO entry");
3952                 return ret;
3953         }
3954
3955         while ((node = rb_first(&delayed_refs->href_root)) != NULL) {
3956                 struct btrfs_delayed_ref_head *head;
3957                 bool pin_bytes = false;
3958
3959                 head = rb_entry(node, struct btrfs_delayed_ref_head,
3960                                 href_node);
3961                 if (!mutex_trylock(&head->mutex)) {
3962                         atomic_inc(&head->node.refs);
3963                         spin_unlock(&delayed_refs->lock);
3964
3965                         mutex_lock(&head->mutex);
3966                         mutex_unlock(&head->mutex);
3967                         btrfs_put_delayed_ref(&head->node);
3968                         spin_lock(&delayed_refs->lock);
3969                         continue;
3970                 }
3971                 spin_lock(&head->lock);
3972                 while ((node = rb_first(&head->ref_root)) != NULL) {
3973                         ref = rb_entry(node, struct btrfs_delayed_ref_node,
3974                                        rb_node);
3975                         ref->in_tree = 0;
3976                         rb_erase(&ref->rb_node, &head->ref_root);
3977                         atomic_dec(&delayed_refs->num_entries);
3978                         btrfs_put_delayed_ref(ref);
3979                 }
3980                 if (head->must_insert_reserved)
3981                         pin_bytes = true;
3982                 btrfs_free_delayed_extent_op(head->extent_op);
3983                 delayed_refs->num_heads--;
3984                 if (head->processing == 0)
3985                         delayed_refs->num_heads_ready--;
3986                 atomic_dec(&delayed_refs->num_entries);
3987                 head->node.in_tree = 0;
3988                 rb_erase(&head->href_node, &delayed_refs->href_root);
3989                 spin_unlock(&head->lock);
3990                 spin_unlock(&delayed_refs->lock);
3991                 mutex_unlock(&head->mutex);
3992
3993                 if (pin_bytes)
3994                         btrfs_pin_extent(root, head->node.bytenr,
3995                                          head->node.num_bytes, 1);
3996                 btrfs_put_delayed_ref(&head->node);
3997                 cond_resched();
3998                 spin_lock(&delayed_refs->lock);
3999         }
4000
4001         spin_unlock(&delayed_refs->lock);
4002
4003         return ret;
4004 }
4005
4006 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
4007 {
4008         struct btrfs_inode *btrfs_inode;
4009         struct list_head splice;
4010
4011         INIT_LIST_HEAD(&splice);
4012
4013         spin_lock(&root->delalloc_lock);
4014         list_splice_init(&root->delalloc_inodes, &splice);
4015
4016         while (!list_empty(&splice)) {
4017                 btrfs_inode = list_first_entry(&splice, struct btrfs_inode,
4018                                                delalloc_inodes);
4019
4020                 list_del_init(&btrfs_inode->delalloc_inodes);
4021                 clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
4022                           &btrfs_inode->runtime_flags);
4023                 spin_unlock(&root->delalloc_lock);
4024
4025                 btrfs_invalidate_inodes(btrfs_inode->root);
4026
4027                 spin_lock(&root->delalloc_lock);
4028         }
4029
4030         spin_unlock(&root->delalloc_lock);
4031 }
4032
4033 static void btrfs_destroy_all_delalloc_inodes(struct btrfs_fs_info *fs_info)
4034 {
4035         struct btrfs_root *root;
4036         struct list_head splice;
4037
4038         INIT_LIST_HEAD(&splice);
4039
4040         spin_lock(&fs_info->delalloc_root_lock);
4041         list_splice_init(&fs_info->delalloc_roots, &splice);
4042         while (!list_empty(&splice)) {
4043                 root = list_first_entry(&splice, struct btrfs_root,
4044                                          delalloc_root);
4045                 list_del_init(&root->delalloc_root);
4046                 root = btrfs_grab_fs_root(root);
4047                 BUG_ON(!root);
4048                 spin_unlock(&fs_info->delalloc_root_lock);
4049
4050                 btrfs_destroy_delalloc_inodes(root);
4051                 btrfs_put_fs_root(root);
4052
4053                 spin_lock(&fs_info->delalloc_root_lock);
4054         }
4055         spin_unlock(&fs_info->delalloc_root_lock);
4056 }
4057
4058 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
4059                                         struct extent_io_tree *dirty_pages,
4060                                         int mark)
4061 {
4062         int ret;
4063         struct extent_buffer *eb;
4064         u64 start = 0;
4065         u64 end;
4066
4067         while (1) {
4068                 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
4069                                             mark, NULL);
4070                 if (ret)
4071                         break;
4072
4073                 clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
4074                 while (start <= end) {
4075                         eb = btrfs_find_tree_block(root, start);
4076                         start += root->nodesize;
4077                         if (!eb)
4078                                 continue;
4079                         wait_on_extent_buffer_writeback(eb);
4080
4081                         if (test_and_clear_bit(EXTENT_BUFFER_DIRTY,
4082                                                &eb->bflags))
4083                                 clear_extent_buffer_dirty(eb);
4084                         free_extent_buffer_stale(eb);
4085                 }
4086         }
4087
4088         return ret;
4089 }
4090
4091 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
4092                                        struct extent_io_tree *pinned_extents)
4093 {
4094         struct extent_io_tree *unpin;
4095         u64 start;
4096         u64 end;
4097         int ret;
4098         bool loop = true;
4099
4100         unpin = pinned_extents;
4101 again:
4102         while (1) {
4103                 ret = find_first_extent_bit(unpin, 0, &start, &end,
4104                                             EXTENT_DIRTY, NULL);
4105                 if (ret)
4106                         break;
4107
4108                 /* opt_discard */
4109                 if (btrfs_test_opt(root, DISCARD))
4110                         ret = btrfs_error_discard_extent(root, start,
4111                                                          end + 1 - start,
4112                                                          NULL);
4113
4114                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
4115                 btrfs_error_unpin_extent_range(root, start, end);
4116                 cond_resched();
4117         }
4118
4119         if (loop) {
4120                 if (unpin == &root->fs_info->freed_extents[0])
4121                         unpin = &root->fs_info->freed_extents[1];
4122                 else
4123                         unpin = &root->fs_info->freed_extents[0];
4124                 loop = false;
4125                 goto again;
4126         }
4127
4128         return 0;
4129 }
4130
4131 void btrfs_cleanup_one_transaction(struct btrfs_transaction *cur_trans,
4132                                    struct btrfs_root *root)
4133 {
4134         btrfs_destroy_delayed_refs(cur_trans, root);
4135
4136         cur_trans->state = TRANS_STATE_COMMIT_START;
4137         wake_up(&root->fs_info->transaction_blocked_wait);
4138
4139         cur_trans->state = TRANS_STATE_UNBLOCKED;
4140         wake_up(&root->fs_info->transaction_wait);
4141
4142         btrfs_destroy_delayed_inodes(root);
4143         btrfs_assert_delayed_root_empty(root);
4144
4145         btrfs_destroy_marked_extents(root, &cur_trans->dirty_pages,
4146                                      EXTENT_DIRTY);
4147         btrfs_destroy_pinned_extent(root,
4148                                     root->fs_info->pinned_extents);
4149
4150         cur_trans->state =TRANS_STATE_COMPLETED;
4151         wake_up(&cur_trans->commit_wait);
4152
4153         /*
4154         memset(cur_trans, 0, sizeof(*cur_trans));
4155         kmem_cache_free(btrfs_transaction_cachep, cur_trans);
4156         */
4157 }
4158
4159 static int btrfs_cleanup_transaction(struct btrfs_root *root)
4160 {
4161         struct btrfs_transaction *t;
4162
4163         mutex_lock(&root->fs_info->transaction_kthread_mutex);
4164
4165         spin_lock(&root->fs_info->trans_lock);
4166         while (!list_empty(&root->fs_info->trans_list)) {
4167                 t = list_first_entry(&root->fs_info->trans_list,
4168                                      struct btrfs_transaction, list);
4169                 if (t->state >= TRANS_STATE_COMMIT_START) {
4170                         atomic_inc(&t->use_count);
4171                         spin_unlock(&root->fs_info->trans_lock);
4172                         btrfs_wait_for_commit(root, t->transid);
4173                         btrfs_put_transaction(t);
4174                         spin_lock(&root->fs_info->trans_lock);
4175                         continue;
4176                 }
4177                 if (t == root->fs_info->running_transaction) {
4178                         t->state = TRANS_STATE_COMMIT_DOING;
4179                         spin_unlock(&root->fs_info->trans_lock);
4180                         /*
4181                          * We wait for 0 num_writers since we don't hold a trans
4182                          * handle open currently for this transaction.
4183                          */
4184                         wait_event(t->writer_wait,
4185                                    atomic_read(&t->num_writers) == 0);
4186                 } else {
4187                         spin_unlock(&root->fs_info->trans_lock);
4188                 }
4189                 btrfs_cleanup_one_transaction(t, root);
4190
4191                 spin_lock(&root->fs_info->trans_lock);
4192                 if (t == root->fs_info->running_transaction)
4193                         root->fs_info->running_transaction = NULL;
4194                 list_del_init(&t->list);
4195                 spin_unlock(&root->fs_info->trans_lock);
4196
4197                 btrfs_put_transaction(t);
4198                 trace_btrfs_transaction_commit(root);
4199                 spin_lock(&root->fs_info->trans_lock);
4200         }
4201         spin_unlock(&root->fs_info->trans_lock);
4202         btrfs_destroy_all_ordered_extents(root->fs_info);
4203         btrfs_destroy_delayed_inodes(root);
4204         btrfs_assert_delayed_root_empty(root);
4205         btrfs_destroy_pinned_extent(root, root->fs_info->pinned_extents);
4206         btrfs_destroy_all_delalloc_inodes(root->fs_info);
4207         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
4208
4209         return 0;
4210 }
4211
4212 static struct extent_io_ops btree_extent_io_ops = {
4213         .readpage_end_io_hook = btree_readpage_end_io_hook,
4214         .readpage_io_failed_hook = btree_io_failed_hook,
4215         .submit_bio_hook = btree_submit_bio_hook,
4216         /* note we're sharing with inode.c for the merge bio hook */
4217         .merge_bio_hook = btrfs_merge_bio_hook,
4218 };