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 const 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_fs_info *fs_info,
 278                            struct extent_buffer *buf,
 279                            int verify)
 280 {
 281         u16 csum_size = btrfs_super_csum_size(fs_info->super_copy);
 282         char *result = NULL;
 283         unsigned long len;
 284         unsigned long cur_len;
 285         unsigned long offset = BTRFS_CSUM_SIZE;
 286         char *kaddr;
 287         unsigned long map_start;
 288         unsigned long map_len;
 289         int err;
 290         u32 crc = ~(u32)0;
 291         unsigned long inline_result;
 292
 293         len = buf->len - offset;
 294         while (len > 0) {
 295                 err = map_private_extent_buffer(buf, offset, 32,
 296                                         &kaddr, &map_start, &map_len);
 297                 if (err)
 298                         return 1;
 299                 cur_len = min(len, map_len - (offset - map_start));
 300                 crc = btrfs_csum_data(kaddr + offset - map_start,
 301                                       crc, cur_len);
 302                 len -= cur_len;
 303                 offset += cur_len;
 304         }
 305         if (csum_size > sizeof(inline_result)) {
 306                 result = kzalloc(csum_size, GFP_NOFS);
 307                 if (!result)
 308                         return 1;
 309         } else {
 310                 result = (char *)&inline_result;
 311         }
 312
 313         btrfs_csum_final(crc, result);
 314
 315         if (verify) {
 316                 if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
 317                         u32 val;
 318                         u32 found = 0;
 319                         memcpy(&found, result, csum_size);
 320
 321                         read_extent_buffer(buf, &val, 0, csum_size);
 322                         printk_ratelimited(KERN_WARNING
 323                                 "BTRFS: %s checksum verify failed on %llu wanted %X found %X "
 324                                 "level %d\n",
 325                                 fs_info->sb->s_id, buf->start,
 326                                 val, found, btrfs_header_level(buf));
 327                         if (result != (char *)&inline_result)
 328                                 kfree(result);
 329                         return 1;
 330                 }
 331         } else {
 332                 write_extent_buffer(buf, result, 0, csum_size);
 333         }
 334         if (result != (char *)&inline_result)
 335                 kfree(result);
 336         return 0;
 337 }
 338
 339 /*
 340  * we can't consider a given block up to date unless the transid of the
 341  * block matches the transid in the parent node's pointer.  This is how we
 342  * detect blocks that either didn't get written at all or got written
 343  * in the wrong place.
 344  */
 345 static int verify_parent_transid(struct extent_io_tree *io_tree,
 346                                  struct extent_buffer *eb, u64 parent_transid,
 347                                  int atomic)
 348 {
 349         struct extent_state *cached_state = NULL;
 350         int ret;
 351         bool need_lock = (current->journal_info == BTRFS_SEND_TRANS_STUB);
 352
 353         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
 354                 return 0;
 355
 356         if (atomic)
 357                 return -EAGAIN;
 358
 359         if (need_lock) {
 360                 btrfs_tree_read_lock(eb);
 361                 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
 362         }
 363
 364         lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
 365                          0, &cached_state);
 366         if (extent_buffer_uptodate(eb) &&
 367             btrfs_header_generation(eb) == parent_transid) {
 368                 ret = 0;
 369                 goto out;
 370         }
 371         printk_ratelimited(KERN_ERR
 372             "BTRFS (device %s): parent transid verify failed on %llu wanted %llu found %llu\n",
 373                         eb->fs_info->sb->s_id, eb->start,
 374                         parent_transid, btrfs_header_generation(eb));
 375         ret = 1;
 376
 377         /*
 378          * Things reading via commit roots that don't have normal protection,
 379          * like send, can have a really old block in cache that may point at a
 380          * block that has been free'd and re-allocated.  So don't clear uptodate
 381          * if we find an eb that is under IO (dirty/writeback) because we could
 382          * end up reading in the stale data and then writing it back out and
 383          * making everybody very sad.
 384          */
 385         if (!extent_buffer_under_io(eb))
 386                 clear_extent_buffer_uptodate(eb);
 387 out:
 388         unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
 389                              &cached_state, GFP_NOFS);
 390         if (need_lock)
 391                 btrfs_tree_read_unlock_blocking(eb);
 392         return ret;
 393 }
 394
 395 /*
 396  * Return 0 if the superblock checksum type matches the checksum value of that
 397  * algorithm. Pass the raw disk superblock data.
 398  */
 399 static int btrfs_check_super_csum(char *raw_disk_sb)
 400 {
 401         struct btrfs_super_block *disk_sb =
 402                 (struct btrfs_super_block *)raw_disk_sb;
 403         u16 csum_type = btrfs_super_csum_type(disk_sb);
 404         int ret = 0;
 405
 406         if (csum_type == BTRFS_CSUM_TYPE_CRC32) {
 407                 u32 crc = ~(u32)0;
 408                 const int csum_size = sizeof(crc);
 409                 char result[csum_size];
 410
 411                 /*
 412                  * The super_block structure does not span the whole
 413                  * BTRFS_SUPER_INFO_SIZE range, we expect that the unused space
 414                  * is filled with zeros and is included in the checkum.
 415                  */
 416                 crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE,
 417                                 crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
 418                 btrfs_csum_final(crc, result);
 419
 420                 if (memcmp(raw_disk_sb, result, csum_size))
 421                         ret = 1;
 422         }
 423
 424         if (csum_type >= ARRAY_SIZE(btrfs_csum_sizes)) {
 425                 printk(KERN_ERR "BTRFS: unsupported checksum algorithm %u\n",
 426                                 csum_type);
 427                 ret = 1;
 428         }
 429
 430         return ret;
 431 }
 432
 433 /*
 434  * helper to read a given tree block, doing retries as required when
 435  * the checksums don't match and we have alternate mirrors to try.
 436  */
 437 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
 438                                           struct extent_buffer *eb,
 439                                           u64 start, u64 parent_transid)
 440 {
 441         struct extent_io_tree *io_tree;
 442         int failed = 0;
 443         int ret;
 444         int num_copies = 0;
 445         int mirror_num = 0;
 446         int failed_mirror = 0;
 447
 448         clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
 449         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
 450         while (1) {
 451                 ret = read_extent_buffer_pages(io_tree, eb, start,
 452                                                WAIT_COMPLETE,
 453                                                btree_get_extent, mirror_num);
 454                 if (!ret) {
 455                         if (!verify_parent_transid(io_tree, eb,
 456                                                    parent_transid, 0))
 457                                 break;
 458                         else
 459                                 ret = -EIO;
 460                 }
 461
 462                 /*
 463                  * This buffer's crc is fine, but its contents are corrupted, so
 464                  * there is no reason to read the other copies, they won't be
 465                  * any less wrong.
 466                  */
 467                 if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags))
 468                         break;
 469
 470                 num_copies = btrfs_num_copies(root->fs_info,
 471                                               eb->start, eb->len);
 472                 if (num_copies == 1)
 473                         break;
 474
 475                 if (!failed_mirror) {
 476                         failed = 1;
 477                         failed_mirror = eb->read_mirror;
 478                 }
 479
 480                 mirror_num++;
 481                 if (mirror_num == failed_mirror)
 482                         mirror_num++;
 483
 484                 if (mirror_num > num_copies)
 485                         break;
 486         }
 487
 488         if (failed && !ret && failed_mirror)
 489                 repair_eb_io_failure(root, eb, failed_mirror);
 490
 491         return ret;
 492 }
 493
 494 /*
 495  * checksum a dirty tree block before IO.  This has extra checks to make sure
 496  * we only fill in the checksum field in the first page of a multi-page block
 497  */
 498
 499 static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct page *page)
 500 {
 501         u64 start = page_offset(page);
 502         u64 found_start;
 503         struct extent_buffer *eb;
 504
 505         eb = (struct extent_buffer *)page->private;
 506         if (page != eb->pages[0])
 507                 return 0;
 508         found_start = btrfs_header_bytenr(eb);
 509         if (WARN_ON(found_start != start || !PageUptodate(page)))
 510                 return 0;
 511         csum_tree_block(fs_info, eb, 0);
 512         return 0;
 513 }
 514
 515 static int check_tree_block_fsid(struct btrfs_fs_info *fs_info,
 516                                  struct extent_buffer *eb)
 517 {
 518         struct btrfs_fs_devices *fs_devices = fs_info->fs_devices;
 519         u8 fsid[BTRFS_UUID_SIZE];
 520         int ret = 1;
 521
 522         read_extent_buffer(eb, fsid, btrfs_header_fsid(), BTRFS_FSID_SIZE);
 523         while (fs_devices) {
 524                 if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
 525                         ret = 0;
 526                         break;
 527                 }
 528                 fs_devices = fs_devices->seed;
 529         }
 530         return ret;
 531 }
 532
 533 #define CORRUPT(reason, eb, root, slot)                         \
 534         btrfs_crit(root->fs_info, "corrupt leaf, %s: block=%llu,"       \
 535                    "root=%llu, slot=%d", reason,                        \
 536                btrfs_header_bytenr(eb), root->objectid, slot)
 537
 538 static noinline int check_leaf(struct btrfs_root *root,
 539                                struct extent_buffer *leaf)
 540 {
 541         struct btrfs_key key;
 542         struct btrfs_key leaf_key;
 543         u32 nritems = btrfs_header_nritems(leaf);
 544         int slot;
 545
 546         if (nritems == 0)
 547                 return 0;
 548
 549         /* Check the 0 item */
 550         if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
 551             BTRFS_LEAF_DATA_SIZE(root)) {
 552                 CORRUPT("invalid item offset size pair", leaf, root, 0);
 553                 return -EIO;
 554         }
 555
 556         /*
 557          * Check to make sure each items keys are in the correct order and their
 558          * offsets make sense.  We only have to loop through nritems-1 because
 559          * we check the current slot against the next slot, which verifies the
 560          * next slot's offset+size makes sense and that the current's slot
 561          * offset is correct.
 562          */
 563         for (slot = 0; slot < nritems - 1; slot++) {
 564                 btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
 565                 btrfs_item_key_to_cpu(leaf, &key, slot + 1);
 566
 567                 /* Make sure the keys are in the right order */
 568                 if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
 569                         CORRUPT("bad key order", leaf, root, slot);
 570                         return -EIO;
 571                 }
 572
 573                 /*
 574                  * Make sure the offset and ends are right, remember that the
 575                  * item data starts at the end of the leaf and grows towards the
 576                  * front.
 577                  */
 578                 if (btrfs_item_offset_nr(leaf, slot) !=
 579                         btrfs_item_end_nr(leaf, slot + 1)) {
 580                         CORRUPT("slot offset bad", leaf, root, slot);
 581                         return -EIO;
 582                 }
 583
 584                 /*
 585                  * Check to make sure that we don't point outside of the leaf,
 586                  * just incase all the items are consistent to eachother, but
 587                  * all point outside of the leaf.
 588                  */
 589                 if (btrfs_item_end_nr(leaf, slot) >
 590                     BTRFS_LEAF_DATA_SIZE(root)) {
 591                         CORRUPT("slot end outside of leaf", leaf, root, slot);
 592                         return -EIO;
 593                 }
 594         }
 595
 596         return 0;
 597 }
 598
 599 static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
 600                                       u64 phy_offset, struct page *page,
 601                                       u64 start, u64 end, int mirror)
 602 {
 603         u64 found_start;
 604         int found_level;
 605         struct extent_buffer *eb;
 606         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 607         int ret = 0;
 608         int reads_done;
 609
 610         if (!page->private)
 611                 goto out;
 612
 613         eb = (struct extent_buffer *)page->private;
 614
 615         /* the pending IO might have been the only thing that kept this buffer
 616          * in memory.  Make sure we have a ref for all this other checks
 617          */
 618         extent_buffer_get(eb);
 619
 620         reads_done = atomic_dec_and_test(&eb->io_pages);
 621         if (!reads_done)
 622                 goto err;
 623
 624         eb->read_mirror = mirror;
 625         if (test_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags)) {
 626                 ret = -EIO;
 627                 goto err;
 628         }
 629
 630         found_start = btrfs_header_bytenr(eb);
 631         if (found_start != eb->start) {
 632                 printk_ratelimited(KERN_ERR "BTRFS (device %s): bad tree block start "
 633                                "%llu %llu\n",
 634                                eb->fs_info->sb->s_id, found_start, eb->start);
 635                 ret = -EIO;
 636                 goto err;
 637         }
 638         if (check_tree_block_fsid(root->fs_info, eb)) {
 639                 printk_ratelimited(KERN_ERR "BTRFS (device %s): bad fsid on block %llu\n",
 640                                eb->fs_info->sb->s_id, eb->start);
 641                 ret = -EIO;
 642                 goto err;
 643         }
 644         found_level = btrfs_header_level(eb);
 645         if (found_level >= BTRFS_MAX_LEVEL) {
 646                 btrfs_err(root->fs_info, "bad tree block level %d",
 647                            (int)btrfs_header_level(eb));
 648                 ret = -EIO;
 649                 goto err;
 650         }
 651
 652         btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb),
 653                                        eb, found_level);
 654
 655         ret = csum_tree_block(root->fs_info, eb, 1);
 656         if (ret) {
 657                 ret = -EIO;
 658                 goto err;
 659         }
 660
 661         /*
 662          * If this is a leaf block and it is corrupt, set the corrupt bit so
 663          * that we don't try and read the other copies of this block, just
 664          * return -EIO.
 665          */
 666         if (found_level == 0 && check_leaf(root, eb)) {
 667                 set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
 668                 ret = -EIO;
 669         }
 670
 671         if (!ret)
 672                 set_extent_buffer_uptodate(eb);
 673 err:
 674         if (reads_done &&
 675             test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
 676                 btree_readahead_hook(root, eb, eb->start, ret);
 677
 678         if (ret) {
 679                 /*
 680                  * our io error hook is going to dec the io pages
 681                  * again, we have to make sure it has something
 682                  * to decrement
 683                  */
 684                 atomic_inc(&eb->io_pages);
 685                 clear_extent_buffer_uptodate(eb);
 686         }
 687         free_extent_buffer(eb);
 688 out:
 689         return ret;
 690 }
 691
 692 static int btree_io_failed_hook(struct page *page, int failed_mirror)
 693 {
 694         struct extent_buffer *eb;
 695         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 696
 697         eb = (struct extent_buffer *)page->private;
 698         set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
 699         eb->read_mirror = failed_mirror;
 700         atomic_dec(&eb->io_pages);
 701         if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
 702                 btree_readahead_hook(root, eb, eb->start, -EIO);
 703         return -EIO;    /* we fixed nothing */
 704 }
 705
 706 static void end_workqueue_bio(struct bio *bio, int err)
 707 {
 708         struct btrfs_end_io_wq *end_io_wq = bio->bi_private;
 709         struct btrfs_fs_info *fs_info;
 710         struct btrfs_workqueue *wq;
 711         btrfs_work_func_t func;
 712
 713         fs_info = end_io_wq->info;
 714         end_io_wq->error = err;
 715
 716         if (bio->bi_rw & REQ_WRITE) {
 717                 if (end_io_wq->metadata == BTRFS_WQ_ENDIO_METADATA) {
 718                         wq = fs_info->endio_meta_write_workers;
 719                         func = btrfs_endio_meta_write_helper;
 720                 } else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_FREE_SPACE) {
 721                         wq = fs_info->endio_freespace_worker;
 722                         func = btrfs_freespace_write_helper;
 723                 } else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56) {
 724                         wq = fs_info->endio_raid56_workers;
 725                         func = btrfs_endio_raid56_helper;
 726                 } else {
 727                         wq = fs_info->endio_write_workers;
 728                         func = btrfs_endio_write_helper;
 729                 }
 730         } else {
 731                 if (unlikely(end_io_wq->metadata ==
 732                              BTRFS_WQ_ENDIO_DIO_REPAIR)) {
 733                         wq = fs_info->endio_repair_workers;
 734                         func = btrfs_endio_repair_helper;
 735                 } else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56) {
 736                         wq = fs_info->endio_raid56_workers;
 737                         func = btrfs_endio_raid56_helper;
 738                 } else if (end_io_wq->metadata) {
 739                         wq = fs_info->endio_meta_workers;
 740                         func = btrfs_endio_meta_helper;
 741                 } else {
 742                         wq = fs_info->endio_workers;
 743                         func = btrfs_endio_helper;
 744                 }
 745         }
 746
 747         btrfs_init_work(&end_io_wq->work, func, end_workqueue_fn, NULL, NULL);
 748         btrfs_queue_work(wq, &end_io_wq->work);
 749 }
 750
 751 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 752                         enum btrfs_wq_endio_type metadata)
 753 {
 754         struct btrfs_end_io_wq *end_io_wq;
 755
 756         end_io_wq = kmem_cache_alloc(btrfs_end_io_wq_cache, GFP_NOFS);
 757         if (!end_io_wq)
 758                 return -ENOMEM;
 759
 760         end_io_wq->private = bio->bi_private;
 761         end_io_wq->end_io = bio->bi_end_io;
 762         end_io_wq->info = info;
 763         end_io_wq->error = 0;
 764         end_io_wq->bio = bio;
 765         end_io_wq->metadata = metadata;
 766
 767         bio->bi_private = end_io_wq;
 768         bio->bi_end_io = end_workqueue_bio;
 769         return 0;
 770 }
 771
 772 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
 773 {
 774         unsigned long limit = min_t(unsigned long,
 775                                     info->thread_pool_size,
 776                                     info->fs_devices->open_devices);
 777         return 256 * limit;
 778 }
 779
 780 static void run_one_async_start(struct btrfs_work *work)
 781 {
 782         struct async_submit_bio *async;
 783         int ret;
 784
 785         async = container_of(work, struct  async_submit_bio, work);
 786         ret = async->submit_bio_start(async->inode, async->rw, async->bio,
 787                                       async->mirror_num, async->bio_flags,
 788                                       async->bio_offset);
 789         if (ret)
 790                 async->error = ret;
 791 }
 792
 793 static void run_one_async_done(struct btrfs_work *work)
 794 {
 795         struct btrfs_fs_info *fs_info;
 796         struct async_submit_bio *async;
 797         int limit;
 798
 799         async = container_of(work, struct  async_submit_bio, work);
 800         fs_info = BTRFS_I(async->inode)->root->fs_info;
 801
 802         limit = btrfs_async_submit_limit(fs_info);
 803         limit = limit * 2 / 3;
 804
 805         if (atomic_dec_return(&fs_info->nr_async_submits) < limit &&
 806             waitqueue_active(&fs_info->async_submit_wait))
 807                 wake_up(&fs_info->async_submit_wait);
 808
 809         /* If an error occured we just want to clean up the bio and move on */
 810         if (async->error) {
 811                 bio_endio(async->bio, async->error);
 812                 return;
 813         }
 814
 815         async->submit_bio_done(async->inode, async->rw, async->bio,
 816                                async->mirror_num, async->bio_flags,
 817                                async->bio_offset);
 818 }
 819
 820 static void run_one_async_free(struct btrfs_work *work)
 821 {
 822         struct async_submit_bio *async;
 823
 824         async = container_of(work, struct  async_submit_bio, work);
 825         kfree(async);
 826 }
 827
 828 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 829                         int rw, struct bio *bio, int mirror_num,
 830                         unsigned long bio_flags,
 831                         u64 bio_offset,
 832                         extent_submit_bio_hook_t *submit_bio_start,
 833                         extent_submit_bio_hook_t *submit_bio_done)
 834 {
 835         struct async_submit_bio *async;
 836
 837         async = kmalloc(sizeof(*async), GFP_NOFS);
 838         if (!async)
 839                 return -ENOMEM;
 840
 841         async->inode = inode;
 842         async->rw = rw;
 843         async->bio = bio;
 844         async->mirror_num = mirror_num;
 845         async->submit_bio_start = submit_bio_start;
 846         async->submit_bio_done = submit_bio_done;
 847
 848         btrfs_init_work(&async->work, btrfs_worker_helper, run_one_async_start,
 849                         run_one_async_done, run_one_async_free);
 850
 851         async->bio_flags = bio_flags;
 852         async->bio_offset = bio_offset;
 853
 854         async->error = 0;
 855
 856         atomic_inc(&fs_info->nr_async_submits);
 857
 858         if (rw & REQ_SYNC)
 859                 btrfs_set_work_high_priority(&async->work);
 860
 861         btrfs_queue_work(fs_info->workers, &async->work);
 862
 863         while (atomic_read(&fs_info->async_submit_draining) &&
 864               atomic_read(&fs_info->nr_async_submits)) {
 865                 wait_event(fs_info->async_submit_wait,
 866                            (atomic_read(&fs_info->nr_async_submits) == 0));
 867         }
 868
 869         return 0;
 870 }
 871
 872 static int btree_csum_one_bio(struct bio *bio)
 873 {
 874         struct bio_vec *bvec;
 875         struct btrfs_root *root;
 876         int i, ret = 0;
 877
 878         bio_for_each_segment_all(bvec, bio, i) {
 879                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
 880                 ret = csum_dirty_buffer(root->fs_info, bvec->bv_page);
 881                 if (ret)
 882                         break;
 883         }
 884
 885         return ret;
 886 }
 887
 888 static int __btree_submit_bio_start(struct inode *inode, int rw,
 889                                     struct bio *bio, int mirror_num,
 890                                     unsigned long bio_flags,
 891                                     u64 bio_offset)
 892 {
 893         /*
 894          * when we're called for a write, we're already in the async
 895          * submission context.  Just jump into btrfs_map_bio
 896          */
 897         return btree_csum_one_bio(bio);
 898 }
 899
 900 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
 901                                  int mirror_num, unsigned long bio_flags,
 902                                  u64 bio_offset)
 903 {
 904         int ret;
 905
 906         /*
 907          * when we're called for a write, we're already in the async
 908          * submission context.  Just jump into btrfs_map_bio
 909          */
 910         ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
 911         if (ret)
 912                 bio_endio(bio, ret);
 913         return ret;
 914 }
 915
 916 static int check_async_write(struct inode *inode, unsigned long bio_flags)
 917 {
 918         if (bio_flags & EXTENT_BIO_TREE_LOG)
 919                 return 0;
 920 #ifdef CONFIG_X86
 921         if (cpu_has_xmm4_2)
 922                 return 0;
 923 #endif
 924         return 1;
 925 }
 926
 927 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 928                                  int mirror_num, unsigned long bio_flags,
 929                                  u64 bio_offset)
 930 {
 931         int async = check_async_write(inode, bio_flags);
 932         int ret;
 933
 934         if (!(rw & REQ_WRITE)) {
 935                 /*
 936                  * called for a read, do the setup so that checksum validation
 937                  * can happen in the async kernel threads
 938                  */
 939                 ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
 940                                           bio, BTRFS_WQ_ENDIO_METADATA);
 941                 if (ret)
 942                         goto out_w_error;
 943                 ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 944                                     mirror_num, 0);
 945         } else if (!async) {
 946                 ret = btree_csum_one_bio(bio);
 947                 if (ret)
 948                         goto out_w_error;
 949                 ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 950                                     mirror_num, 0);
 951         } else {
 952                 /*
 953                  * kthread helpers are used to submit writes so that
 954                  * checksumming can happen in parallel across all CPUs
 955                  */
 956                 ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
 957                                           inode, rw, bio, mirror_num, 0,
 958                                           bio_offset,
 959                                           __btree_submit_bio_start,
 960                                           __btree_submit_bio_done);
 961         }
 962
 963         if (ret) {
 964 out_w_error:
 965                 bio_endio(bio, ret);
 966         }
 967         return ret;
 968 }
 969
 970 #ifdef CONFIG_MIGRATION
 971 static int btree_migratepage(struct address_space *mapping,
 972                         struct page *newpage, struct page *page,
 973                         enum migrate_mode mode)
 974 {
 975         /*
 976          * we can't safely write a btree page from here,
 977          * we haven't done the locking hook
 978          */
 979         if (PageDirty(page))
 980                 return -EAGAIN;
 981         /*
 982          * Buffers may be managed in a filesystem specific way.
 983          * We must have no buffers or drop them.
 984          */
 985         if (page_has_private(page) &&
 986             !try_to_release_page(page, GFP_KERNEL))
 987                 return -EAGAIN;
 988         return migrate_page(mapping, newpage, page, mode);
 989 }
 990 #endif
 991
 992
 993 static int btree_writepages(struct address_space *mapping,
 994                             struct writeback_control *wbc)
 995 {
 996         struct btrfs_fs_info *fs_info;
 997         int ret;
 998
 999         if (wbc->sync_mode == WB_SYNC_NONE) {
1000
1001                 if (wbc->for_kupdate)
1002                         return 0;
1003
1004                 fs_info = BTRFS_I(mapping->host)->root->fs_info;
1005                 /* this is a bit racy, but that's ok */
1006                 ret = percpu_counter_compare(&fs_info->dirty_metadata_bytes,
1007                                              BTRFS_DIRTY_METADATA_THRESH);
1008                 if (ret < 0)
1009                         return 0;
1010         }
1011         return btree_write_cache_pages(mapping, wbc);
1012 }
1013
1014 static int btree_readpage(struct file *file, struct page *page)
1015 {
1016         struct extent_io_tree *tree;
1017         tree = &BTRFS_I(page->mapping->host)->io_tree;
1018         return extent_read_full_page(tree, page, btree_get_extent, 0);
1019 }
1020
1021 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
1022 {
1023         if (PageWriteback(page) || PageDirty(page))
1024                 return 0;
1025
1026         return try_release_extent_buffer(page);
1027 }
1028
1029 static void btree_invalidatepage(struct page *page, unsigned int offset,
1030                                  unsigned int length)
1031 {
1032         struct extent_io_tree *tree;
1033         tree = &BTRFS_I(page->mapping->host)->io_tree;
1034         extent_invalidatepage(tree, page, offset);
1035         btree_releasepage(page, GFP_NOFS);
1036         if (PagePrivate(page)) {
1037                 btrfs_warn(BTRFS_I(page->mapping->host)->root->fs_info,
1038                            "page private not zero on page %llu",
1039                            (unsigned long long)page_offset(page));
1040                 ClearPagePrivate(page);
1041                 set_page_private(page, 0);
1042                 page_cache_release(page);
1043         }
1044 }
1045
1046 static int btree_set_page_dirty(struct page *page)
1047 {
1048 #ifdef DEBUG
1049         struct extent_buffer *eb;
1050
1051         BUG_ON(!PagePrivate(page));
1052         eb = (struct extent_buffer *)page->private;
1053         BUG_ON(!eb);
1054         BUG_ON(!test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
1055         BUG_ON(!atomic_read(&eb->refs));
1056         btrfs_assert_tree_locked(eb);
1057 #endif
1058         return __set_page_dirty_nobuffers(page);
1059 }
1060
1061 static const struct address_space_operations btree_aops = {
1062         .readpage       = btree_readpage,
1063         .writepages     = btree_writepages,
1064         .releasepage    = btree_releasepage,
1065         .invalidatepage = btree_invalidatepage,
1066 #ifdef CONFIG_MIGRATION
1067         .migratepage    = btree_migratepage,
1068 #endif
1069         .set_page_dirty = btree_set_page_dirty,
1070 };
1071
1072 void readahead_tree_block(struct btrfs_root *root, u64 bytenr)
1073 {
1074         struct extent_buffer *buf = NULL;
1075         struct inode *btree_inode = root->fs_info->btree_inode;
1076
1077         buf = btrfs_find_create_tree_block(root, bytenr);
1078         if (!buf)
1079                 return;
1080         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
1081                                  buf, 0, WAIT_NONE, btree_get_extent, 0);
1082         free_extent_buffer(buf);
1083 }
1084
1085 int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr,
1086                          int mirror_num, struct extent_buffer **eb)
1087 {
1088         struct extent_buffer *buf = NULL;
1089         struct inode *btree_inode = root->fs_info->btree_inode;
1090         struct extent_io_tree *io_tree = &BTRFS_I(btree_inode)->io_tree;
1091         int ret;
1092
1093         buf = btrfs_find_create_tree_block(root, bytenr);
1094         if (!buf)
1095                 return 0;
1096
1097         set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
1098
1099         ret = read_extent_buffer_pages(io_tree, buf, 0, WAIT_PAGE_LOCK,
1100                                        btree_get_extent, mirror_num);
1101         if (ret) {
1102                 free_extent_buffer(buf);
1103                 return ret;
1104         }
1105
1106         if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
1107                 free_extent_buffer(buf);
1108                 return -EIO;
1109         } else if (extent_buffer_uptodate(buf)) {
1110                 *eb = buf;
1111         } else {
1112                 free_extent_buffer(buf);
1113         }
1114         return 0;
1115 }
1116
1117 struct extent_buffer *btrfs_find_tree_block(struct btrfs_fs_info *fs_info,
1118                                             u64 bytenr)
1119 {
1120         return find_extent_buffer(fs_info, bytenr);
1121 }
1122
1123 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
1124                                                  u64 bytenr)
1125 {
1126         if (btrfs_test_is_dummy_root(root))
1127                 return alloc_test_extent_buffer(root->fs_info, bytenr);
1128         return alloc_extent_buffer(root->fs_info, bytenr);
1129 }
1130
1131
1132 int btrfs_write_tree_block(struct extent_buffer *buf)
1133 {
1134         return filemap_fdatawrite_range(buf->pages[0]->mapping, buf->start,
1135                                         buf->start + buf->len - 1);
1136 }
1137
1138 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
1139 {
1140         return filemap_fdatawait_range(buf->pages[0]->mapping,
1141                                        buf->start, buf->start + buf->len - 1);
1142 }
1143
1144 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
1145                                       u64 parent_transid)
1146 {
1147         struct extent_buffer *buf = NULL;
1148         int ret;
1149
1150         buf = btrfs_find_create_tree_block(root, bytenr);
1151         if (!buf)
1152                 return ERR_PTR(-ENOMEM);
1153
1154         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1155         if (ret) {
1156                 free_extent_buffer(buf);
1157                 return ERR_PTR(ret);
1158         }
1159         return buf;
1160
1161 }
1162
1163 void clean_tree_block(struct btrfs_trans_handle *trans,
1164                       struct btrfs_fs_info *fs_info,
1165                       struct extent_buffer *buf)
1166 {
1167         if (btrfs_header_generation(buf) ==
1168             fs_info->running_transaction->transid) {
1169                 btrfs_assert_tree_locked(buf);
1170
1171                 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
1172                         __percpu_counter_add(&fs_info->dirty_metadata_bytes,
1173                                              -buf->len,
1174                                              fs_info->dirty_metadata_batch);
1175                         /* ugh, clear_extent_buffer_dirty needs to lock the page */
1176                         btrfs_set_lock_blocking(buf);
1177                         clear_extent_buffer_dirty(buf);
1178                 }
1179         }
1180 }
1181
1182 static struct btrfs_subvolume_writers *btrfs_alloc_subvolume_writers(void)
1183 {
1184         struct btrfs_subvolume_writers *writers;
1185         int ret;
1186
1187         writers = kmalloc(sizeof(*writers), GFP_NOFS);
1188         if (!writers)
1189                 return ERR_PTR(-ENOMEM);
1190
1191         ret = percpu_counter_init(&writers->counter, 0, GFP_KERNEL);
1192         if (ret < 0) {
1193                 kfree(writers);
1194                 return ERR_PTR(ret);
1195         }
1196
1197         init_waitqueue_head(&writers->wait);
1198         return writers;
1199 }
1200
1201 static void
1202 btrfs_free_subvolume_writers(struct btrfs_subvolume_writers *writers)
1203 {
1204         percpu_counter_destroy(&writers->counter);
1205         kfree(writers);
1206 }
1207
1208 static void __setup_root(u32 nodesize, u32 sectorsize, u32 stripesize,
1209                          struct btrfs_root *root, struct btrfs_fs_info *fs_info,
1210                          u64 objectid)
1211 {
1212         root->node = NULL;
1213         root->commit_root = NULL;
1214         root->sectorsize = sectorsize;
1215         root->nodesize = nodesize;
1216         root->stripesize = stripesize;
1217         root->state = 0;
1218         root->orphan_cleanup_state = 0;
1219
1220         root->objectid = objectid;
1221         root->last_trans = 0;
1222         root->highest_objectid = 0;
1223         root->nr_delalloc_inodes = 0;
1224         root->nr_ordered_extents = 0;
1225         root->name = NULL;
1226         root->inode_tree = RB_ROOT;
1227         INIT_RADIX_TREE(&root->delayed_nodes_tree, GFP_ATOMIC);
1228         root->block_rsv = NULL;
1229         root->orphan_block_rsv = NULL;
1230
1231         INIT_LIST_HEAD(&root->dirty_list);
1232         INIT_LIST_HEAD(&root->root_list);
1233         INIT_LIST_HEAD(&root->delalloc_inodes);
1234         INIT_LIST_HEAD(&root->delalloc_root);
1235         INIT_LIST_HEAD(&root->ordered_extents);
1236         INIT_LIST_HEAD(&root->ordered_root);
1237         INIT_LIST_HEAD(&root->logged_list[0]);
1238         INIT_LIST_HEAD(&root->logged_list[1]);
1239         spin_lock_init(&root->orphan_lock);
1240         spin_lock_init(&root->inode_lock);
1241         spin_lock_init(&root->delalloc_lock);
1242         spin_lock_init(&root->ordered_extent_lock);
1243         spin_lock_init(&root->accounting_lock);
1244         spin_lock_init(&root->log_extents_lock[0]);
1245         spin_lock_init(&root->log_extents_lock[1]);
1246         mutex_init(&root->objectid_mutex);
1247         mutex_init(&root->log_mutex);
1248         mutex_init(&root->ordered_extent_mutex);
1249         mutex_init(&root->delalloc_mutex);
1250         init_waitqueue_head(&root->log_writer_wait);
1251         init_waitqueue_head(&root->log_commit_wait[0]);
1252         init_waitqueue_head(&root->log_commit_wait[1]);
1253         INIT_LIST_HEAD(&root->log_ctxs[0]);
1254         INIT_LIST_HEAD(&root->log_ctxs[1]);
1255         atomic_set(&root->log_commit[0], 0);
1256         atomic_set(&root->log_commit[1], 0);
1257         atomic_set(&root->log_writers, 0);
1258         atomic_set(&root->log_batch, 0);
1259         atomic_set(&root->orphan_inodes, 0);
1260         atomic_set(&root->refs, 1);
1261         atomic_set(&root->will_be_snapshoted, 0);
1262         root->log_transid = 0;
1263         root->log_transid_committed = -1;
1264         root->last_log_commit = 0;
1265         if (fs_info)
1266                 extent_io_tree_init(&root->dirty_log_pages,
1267                                      fs_info->btree_inode->i_mapping);
1268
1269         memset(&root->root_key, 0, sizeof(root->root_key));
1270         memset(&root->root_item, 0, sizeof(root->root_item));
1271         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
1272         if (fs_info)
1273                 root->defrag_trans_start = fs_info->generation;
1274         else
1275                 root->defrag_trans_start = 0;
1276         root->root_key.objectid = objectid;
1277         root->anon_dev = 0;
1278
1279         spin_lock_init(&root->root_item_lock);
1280 }
1281
1282 static struct btrfs_root *btrfs_alloc_root(struct btrfs_fs_info *fs_info)
1283 {
1284         struct btrfs_root *root = kzalloc(sizeof(*root), GFP_NOFS);
1285         if (root)
1286                 root->fs_info = fs_info;
1287         return root;
1288 }
1289
1290 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
1291 /* Should only be used by the testing infrastructure */
1292 struct btrfs_root *btrfs_alloc_dummy_root(void)
1293 {
1294         struct btrfs_root *root;
1295
1296         root = btrfs_alloc_root(NULL);
1297         if (!root)
1298                 return ERR_PTR(-ENOMEM);
1299         __setup_root(4096, 4096, 4096, root, NULL, 1);
1300         set_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state);
1301         root->alloc_bytenr = 0;
1302
1303         return root;
1304 }
1305 #endif
1306
1307 struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
1308                                      struct btrfs_fs_info *fs_info,
1309                                      u64 objectid)
1310 {
1311         struct extent_buffer *leaf;
1312         struct btrfs_root *tree_root = fs_info->tree_root;
1313         struct btrfs_root *root;
1314         struct btrfs_key key;
1315         int ret = 0;
1316         uuid_le uuid;
1317
1318         root = btrfs_alloc_root(fs_info);
1319         if (!root)
1320                 return ERR_PTR(-ENOMEM);
1321
1322         __setup_root(tree_root->nodesize, tree_root->sectorsize,
1323                 tree_root->stripesize, root, fs_info, objectid);
1324         root->root_key.objectid = objectid;
1325         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1326         root->root_key.offset = 0;
1327
1328         leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);
1329         if (IS_ERR(leaf)) {
1330                 ret = PTR_ERR(leaf);
1331                 leaf = NULL;
1332                 goto fail;
1333         }
1334
1335         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1336         btrfs_set_header_bytenr(leaf, leaf->start);
1337         btrfs_set_header_generation(leaf, trans->transid);
1338         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1339         btrfs_set_header_owner(leaf, objectid);
1340         root->node = leaf;
1341
1342         write_extent_buffer(leaf, fs_info->fsid, btrfs_header_fsid(),
1343                             BTRFS_FSID_SIZE);
1344         write_extent_buffer(leaf, fs_info->chunk_tree_uuid,
1345                             btrfs_header_chunk_tree_uuid(leaf),
1346                             BTRFS_UUID_SIZE);
1347         btrfs_mark_buffer_dirty(leaf);
1348
1349         root->commit_root = btrfs_root_node(root);
1350         set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
1351
1352         root->root_item.flags = 0;
1353         root->root_item.byte_limit = 0;
1354         btrfs_set_root_bytenr(&root->root_item, leaf->start);
1355         btrfs_set_root_generation(&root->root_item, trans->transid);
1356         btrfs_set_root_level(&root->root_item, 0);
1357         btrfs_set_root_refs(&root->root_item, 1);
1358         btrfs_set_root_used(&root->root_item, leaf->len);
1359         btrfs_set_root_last_snapshot(&root->root_item, 0);
1360         btrfs_set_root_dirid(&root->root_item, 0);
1361         uuid_le_gen(&uuid);
1362         memcpy(root->root_item.uuid, uuid.b, BTRFS_UUID_SIZE);
1363         root->root_item.drop_level = 0;
1364
1365         key.objectid = objectid;
1366         key.type = BTRFS_ROOT_ITEM_KEY;
1367         key.offset = 0;
1368         ret = btrfs_insert_root(trans, tree_root, &key, &root->root_item);
1369         if (ret)
1370                 goto fail;
1371
1372         btrfs_tree_unlock(leaf);
1373
1374         return root;
1375
1376 fail:
1377         if (leaf) {
1378                 btrfs_tree_unlock(leaf);
1379                 free_extent_buffer(root->commit_root);
1380                 free_extent_buffer(leaf);
1381         }
1382         kfree(root);
1383
1384         return ERR_PTR(ret);
1385 }
1386
1387 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1388                                          struct btrfs_fs_info *fs_info)
1389 {
1390         struct btrfs_root *root;
1391         struct btrfs_root *tree_root = fs_info->tree_root;
1392         struct extent_buffer *leaf;
1393
1394         root = btrfs_alloc_root(fs_info);
1395         if (!root)
1396                 return ERR_PTR(-ENOMEM);
1397
1398         __setup_root(tree_root->nodesize, tree_root->sectorsize,
1399                      tree_root->stripesize, root, fs_info,
1400                      BTRFS_TREE_LOG_OBJECTID);
1401
1402         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1403         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1404         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1405
1406         /*
1407          * DON'T set REF_COWS for log trees
1408          *
1409          * log trees do not get reference counted because they go away
1410          * before a real commit is actually done.  They do store pointers
1411          * to file data extents, and those reference counts still get
1412          * updated (along with back refs to the log tree).
1413          */
1414
1415         leaf = btrfs_alloc_tree_block(trans, root, 0, BTRFS_TREE_LOG_OBJECTID,
1416                         NULL, 0, 0, 0);
1417         if (IS_ERR(leaf)) {
1418                 kfree(root);
1419                 return ERR_CAST(leaf);
1420         }
1421
1422         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1423         btrfs_set_header_bytenr(leaf, leaf->start);
1424         btrfs_set_header_generation(leaf, trans->transid);
1425         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1426         btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1427         root->node = leaf;
1428
1429         write_extent_buffer(root->node, root->fs_info->fsid,
1430                             btrfs_header_fsid(), BTRFS_FSID_SIZE);
1431         btrfs_mark_buffer_dirty(root->node);
1432         btrfs_tree_unlock(root->node);
1433         return root;
1434 }
1435
1436 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1437                              struct btrfs_fs_info *fs_info)
1438 {
1439         struct btrfs_root *log_root;
1440
1441         log_root = alloc_log_tree(trans, fs_info);
1442         if (IS_ERR(log_root))
1443                 return PTR_ERR(log_root);
1444         WARN_ON(fs_info->log_root_tree);
1445         fs_info->log_root_tree = log_root;
1446         return 0;
1447 }
1448
1449 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1450                        struct btrfs_root *root)
1451 {
1452         struct btrfs_root *log_root;
1453         struct btrfs_inode_item *inode_item;
1454
1455         log_root = alloc_log_tree(trans, root->fs_info);
1456         if (IS_ERR(log_root))
1457                 return PTR_ERR(log_root);
1458
1459         log_root->last_trans = trans->transid;
1460         log_root->root_key.offset = root->root_key.objectid;
1461
1462         inode_item = &log_root->root_item.inode;
1463         btrfs_set_stack_inode_generation(inode_item, 1);
1464         btrfs_set_stack_inode_size(inode_item, 3);
1465         btrfs_set_stack_inode_nlink(inode_item, 1);
1466         btrfs_set_stack_inode_nbytes(inode_item, root->nodesize);
1467         btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
1468
1469         btrfs_set_root_node(&log_root->root_item, log_root->node);
1470
1471         WARN_ON(root->log_root);
1472         root->log_root = log_root;
1473         root->log_transid = 0;
1474         root->log_transid_committed = -1;
1475         root->last_log_commit = 0;
1476         return 0;
1477 }
1478
1479 static struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
1480                                                struct btrfs_key *key)
1481 {
1482         struct btrfs_root *root;
1483         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1484         struct btrfs_path *path;
1485         u64 generation;
1486         int ret;
1487
1488         path = btrfs_alloc_path();
1489         if (!path)
1490                 return ERR_PTR(-ENOMEM);
1491
1492         root = btrfs_alloc_root(fs_info);
1493         if (!root) {
1494                 ret = -ENOMEM;
1495                 goto alloc_fail;
1496         }
1497
1498         __setup_root(tree_root->nodesize, tree_root->sectorsize,
1499                 tree_root->stripesize, root, fs_info, key->objectid);
1500
1501         ret = btrfs_find_root(tree_root, key, path,
1502                               &root->root_item, &root->root_key);
1503         if (ret) {
1504                 if (ret > 0)
1505                         ret = -ENOENT;
1506                 goto find_fail;
1507         }
1508
1509         generation = btrfs_root_generation(&root->root_item);
1510         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1511                                      generation);
1512         if (IS_ERR(root->node)) {
1513                 ret = PTR_ERR(root->node);
1514                 goto find_fail;
1515         } else if (!btrfs_buffer_uptodate(root->node, generation, 0)) {
1516                 ret = -EIO;
1517                 free_extent_buffer(root->node);
1518                 goto find_fail;
1519         }
1520         root->commit_root = btrfs_root_node(root);
1521 out:
1522         btrfs_free_path(path);
1523         return root;
1524
1525 find_fail:
1526         kfree(root);
1527 alloc_fail:
1528         root = ERR_PTR(ret);
1529         goto out;
1530 }
1531
1532 struct btrfs_root *btrfs_read_fs_root(struct btrfs_root *tree_root,
1533                                       struct btrfs_key *location)
1534 {
1535         struct btrfs_root *root;
1536
1537         root = btrfs_read_tree_root(tree_root, location);
1538         if (IS_ERR(root))
1539                 return root;
1540
1541         if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
1542                 set_bit(BTRFS_ROOT_REF_COWS, &root->state);
1543                 btrfs_check_and_init_root_item(&root->root_item);
1544         }
1545
1546         return root;
1547 }
1548
1549 int btrfs_init_fs_root(struct btrfs_root *root)
1550 {
1551         int ret;
1552         struct btrfs_subvolume_writers *writers;
1553
1554         root->free_ino_ctl = kzalloc(sizeof(*root->free_ino_ctl), GFP_NOFS);
1555         root->free_ino_pinned = kzalloc(sizeof(*root->free_ino_pinned),
1556                                         GFP_NOFS);
1557         if (!root->free_ino_pinned || !root->free_ino_ctl) {
1558                 ret = -ENOMEM;
1559                 goto fail;
1560         }
1561
1562         writers = btrfs_alloc_subvolume_writers();
1563         if (IS_ERR(writers)) {
1564                 ret = PTR_ERR(writers);
1565                 goto fail;
1566         }
1567         root->subv_writers = writers;
1568
1569         btrfs_init_free_ino_ctl(root);
1570         spin_lock_init(&root->ino_cache_lock);
1571         init_waitqueue_head(&root->ino_cache_wait);
1572
1573         ret = get_anon_bdev(&root->anon_dev);
1574         if (ret)
1575                 goto free_writers;
1576         return 0;
1577
1578 free_writers:
1579         btrfs_free_subvolume_writers(root->subv_writers);
1580 fail:
1581         kfree(root->free_ino_ctl);
1582         kfree(root->free_ino_pinned);
1583         return ret;
1584 }
1585
1586 static struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1587                                                u64 root_id)
1588 {
1589         struct btrfs_root *root;
1590
1591         spin_lock(&fs_info->fs_roots_radix_lock);
1592         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1593                                  (unsigned long)root_id);
1594         spin_unlock(&fs_info->fs_roots_radix_lock);
1595         return root;
1596 }
1597
1598 int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
1599                          struct btrfs_root *root)
1600 {
1601         int ret;
1602
1603         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1604         if (ret)
1605                 return ret;
1606
1607         spin_lock(&fs_info->fs_roots_radix_lock);
1608         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1609                                 (unsigned long)root->root_key.objectid,
1610                                 root);
1611         if (ret == 0)
1612                 set_bit(BTRFS_ROOT_IN_RADIX, &root->state);
1613         spin_unlock(&fs_info->fs_roots_radix_lock);
1614         radix_tree_preload_end();
1615
1616         return ret;
1617 }
1618
1619 struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
1620                                      struct btrfs_key *location,
1621                                      bool check_ref)
1622 {
1623         struct btrfs_root *root;
1624         struct btrfs_path *path;
1625         struct btrfs_key key;
1626         int ret;
1627
1628         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1629                 return fs_info->tree_root;
1630         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1631                 return fs_info->extent_root;
1632         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1633                 return fs_info->chunk_root;
1634         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1635                 return fs_info->dev_root;
1636         if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1637                 return fs_info->csum_root;
1638         if (location->objectid == BTRFS_QUOTA_TREE_OBJECTID)
1639                 return fs_info->quota_root ? fs_info->quota_root :
1640                                              ERR_PTR(-ENOENT);
1641         if (location->objectid == BTRFS_UUID_TREE_OBJECTID)
1642                 return fs_info->uuid_root ? fs_info->uuid_root :
1643                                             ERR_PTR(-ENOENT);
1644 again:
1645         root = btrfs_lookup_fs_root(fs_info, location->objectid);
1646         if (root) {
1647                 if (check_ref && btrfs_root_refs(&root->root_item) == 0)
1648                         return ERR_PTR(-ENOENT);
1649                 return root;
1650         }
1651
1652         root = btrfs_read_fs_root(fs_info->tree_root, location);
1653         if (IS_ERR(root))
1654                 return root;
1655
1656         if (check_ref && btrfs_root_refs(&root->root_item) == 0) {
1657                 ret = -ENOENT;
1658                 goto fail;
1659         }
1660
1661         ret = btrfs_init_fs_root(root);
1662         if (ret)
1663                 goto fail;
1664
1665         path = btrfs_alloc_path();
1666         if (!path) {
1667                 ret = -ENOMEM;
1668                 goto fail;
1669         }
1670         key.objectid = BTRFS_ORPHAN_OBJECTID;
1671         key.type = BTRFS_ORPHAN_ITEM_KEY;
1672         key.offset = location->objectid;
1673
1674         ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
1675         btrfs_free_path(path);
1676         if (ret < 0)
1677                 goto fail;
1678         if (ret == 0)
1679                 set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
1680
1681         ret = btrfs_insert_fs_root(fs_info, root);
1682         if (ret) {
1683                 if (ret == -EEXIST) {
1684                         free_fs_root(root);
1685                         goto again;
1686                 }
1687                 goto fail;
1688         }
1689         return root;
1690 fail:
1691         free_fs_root(root);
1692         return ERR_PTR(ret);
1693 }
1694
1695 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1696 {
1697         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1698         int ret = 0;
1699         struct btrfs_device *device;
1700         struct backing_dev_info *bdi;
1701
1702         rcu_read_lock();
1703         list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
1704                 if (!device->bdev)
1705                         continue;
1706                 bdi = blk_get_backing_dev_info(device->bdev);
1707                 if (bdi_congested(bdi, bdi_bits)) {
1708                         ret = 1;
1709                         break;
1710                 }
1711         }
1712         rcu_read_unlock();
1713         return ret;
1714 }
1715
1716 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1717 {
1718         int err;
1719
1720         err = bdi_setup_and_register(bdi, "btrfs");
1721         if (err)
1722                 return err;
1723
1724         bdi->ra_pages = VM_MAX_READAHEAD * 1024 / PAGE_CACHE_SIZE;
1725         bdi->congested_fn       = btrfs_congested_fn;
1726         bdi->congested_data     = info;
1727         bdi->capabilities |= BDI_CAP_CGROUP_WRITEBACK;
1728         return 0;
1729 }
1730
1731 /*
1732  * called by the kthread helper functions to finally call the bio end_io
1733  * functions.  This is where read checksum verification actually happens
1734  */
1735 static void end_workqueue_fn(struct btrfs_work *work)
1736 {
1737         struct bio *bio;
1738         struct btrfs_end_io_wq *end_io_wq;
1739         int error;
1740
1741         end_io_wq = container_of(work, struct btrfs_end_io_wq, work);
1742         bio = end_io_wq->bio;
1743
1744         error = end_io_wq->error;
1745         bio->bi_private = end_io_wq->private;
1746         bio->bi_end_io = end_io_wq->end_io;
1747         kmem_cache_free(btrfs_end_io_wq_cache, end_io_wq);
1748         bio_endio(bio, error);
1749 }
1750
1751 static int cleaner_kthread(void *arg)
1752 {
1753         struct btrfs_root *root = arg;
1754         int again;
1755         struct btrfs_trans_handle *trans;
1756
1757         do {
1758                 again = 0;
1759
1760                 /* Make the cleaner go to sleep early. */
1761                 if (btrfs_need_cleaner_sleep(root))
1762                         goto sleep;
1763
1764                 if (!mutex_trylock(&root->fs_info->cleaner_mutex))
1765                         goto sleep;
1766
1767                 /*
1768                  * Avoid the problem that we change the status of the fs
1769                  * during the above check and trylock.
1770                  */
1771                 if (btrfs_need_cleaner_sleep(root)) {
1772                         mutex_unlock(&root->fs_info->cleaner_mutex);
1773                         goto sleep;
1774                 }
1775
1776                 btrfs_run_delayed_iputs(root);
1777                 again = btrfs_clean_one_deleted_snapshot(root);
1778                 mutex_unlock(&root->fs_info->cleaner_mutex);
1779
1780                 /*
1781                  * The defragger has dealt with the R/O remount and umount,
1782                  * needn't do anything special here.
1783                  */
1784                 btrfs_run_defrag_inodes(root->fs_info);
1785
1786                 /*
1787                  * Acquires fs_info->delete_unused_bgs_mutex to avoid racing
1788                  * with relocation (btrfs_relocate_chunk) and relocation
1789                  * acquires fs_info->cleaner_mutex (btrfs_relocate_block_group)
1790                  * after acquiring fs_info->delete_unused_bgs_mutex. So we
1791                  * can't hold, nor need to, fs_info->cleaner_mutex when deleting
1792                  * unused block groups.
1793                  */
1794                 btrfs_delete_unused_bgs(root->fs_info);
1795 sleep:
1796                 if (!try_to_freeze() && !again) {
1797                         set_current_state(TASK_INTERRUPTIBLE);
1798                         if (!kthread_should_stop())
1799                                 schedule();
1800                         __set_current_state(TASK_RUNNING);
1801                 }
1802         } while (!kthread_should_stop());
1803
1804         /*
1805          * Transaction kthread is stopped before us and wakes us up.
1806          * However we might have started a new transaction and COWed some
1807          * tree blocks when deleting unused block groups for example. So
1808          * make sure we commit the transaction we started to have a clean
1809          * shutdown when evicting the btree inode - if it has dirty pages
1810          * when we do the final iput() on it, eviction will trigger a
1811          * writeback for it which will fail with null pointer dereferences
1812          * since work queues and other resources were already released and
1813          * destroyed by the time the iput/eviction/writeback is made.
1814          */
1815         trans = btrfs_attach_transaction(root);
1816         if (IS_ERR(trans)) {
1817                 if (PTR_ERR(trans) != -ENOENT)
1818                         btrfs_err(root->fs_info,
1819                                   "cleaner transaction attach returned %ld",
1820                                   PTR_ERR(trans));
1821         } else {
1822                 int ret;
1823
1824                 ret = btrfs_commit_transaction(trans, root);
1825                 if (ret)
1826                         btrfs_err(root->fs_info,
1827                                   "cleaner open transaction commit returned %d",
1828                                   ret);
1829         }
1830
1831         return 0;
1832 }
1833
1834 static int transaction_kthread(void *arg)
1835 {
1836         struct btrfs_root *root = arg;
1837         struct btrfs_trans_handle *trans;
1838         struct btrfs_transaction *cur;
1839         u64 transid;
1840         unsigned long now;
1841         unsigned long delay;
1842         bool cannot_commit;
1843
1844         do {
1845                 cannot_commit = false;
1846                 delay = HZ * root->fs_info->commit_interval;
1847                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1848
1849                 spin_lock(&root->fs_info->trans_lock);
1850                 cur = root->fs_info->running_transaction;
1851                 if (!cur) {
1852                         spin_unlock(&root->fs_info->trans_lock);
1853                         goto sleep;
1854                 }
1855
1856                 now = get_seconds();
1857                 if (cur->state < TRANS_STATE_BLOCKED &&
1858                     (now < cur->start_time ||
1859                      now - cur->start_time < root->fs_info->commit_interval)) {
1860                         spin_unlock(&root->fs_info->trans_lock);
1861                         delay = HZ * 5;
1862                         goto sleep;
1863                 }
1864                 transid = cur->transid;
1865                 spin_unlock(&root->fs_info->trans_lock);
1866
1867                 /* If the file system is aborted, this will always fail. */
1868                 trans = btrfs_attach_transaction(root);
1869                 if (IS_ERR(trans)) {
1870                         if (PTR_ERR(trans) != -ENOENT)
1871                                 cannot_commit = true;
1872                         goto sleep;
1873                 }
1874                 if (transid == trans->transid) {
1875                         btrfs_commit_transaction(trans, root);
1876                 } else {
1877                         btrfs_end_transaction(trans, root);
1878                 }
1879 sleep:
1880                 wake_up_process(root->fs_info->cleaner_kthread);
1881                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1882
1883                 if (unlikely(test_bit(BTRFS_FS_STATE_ERROR,
1884                                       &root->fs_info->fs_state)))
1885                         btrfs_cleanup_transaction(root);
1886                 if (!try_to_freeze()) {
1887                         set_current_state(TASK_INTERRUPTIBLE);
1888                         if (!kthread_should_stop() &&
1889                             (!btrfs_transaction_blocked(root->fs_info) ||
1890                              cannot_commit))
1891                                 schedule_timeout(delay);
1892                         __set_current_state(TASK_RUNNING);
1893                 }
1894         } while (!kthread_should_stop());
1895         return 0;
1896 }
1897
1898 /*
1899  * this will find the highest generation in the array of
1900  * root backups.  The index of the highest array is returned,
1901  * or -1 if we can't find anything.
1902  *
1903  * We check to make sure the array is valid by comparing the
1904  * generation of the latest  root in the array with the generation
1905  * in the super block.  If they don't match we pitch it.
1906  */
1907 static int find_newest_super_backup(struct btrfs_fs_info *info, u64 newest_gen)
1908 {
1909         u64 cur;
1910         int newest_index = -1;
1911         struct btrfs_root_backup *root_backup;
1912         int i;
1913
1914         for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
1915                 root_backup = info->super_copy->super_roots + i;
1916                 cur = btrfs_backup_tree_root_gen(root_backup);
1917                 if (cur == newest_gen)
1918                         newest_index = i;
1919         }
1920
1921         /* check to see if we actually wrapped around */
1922         if (newest_index == BTRFS_NUM_BACKUP_ROOTS - 1) {
1923                 root_backup = info->super_copy->super_roots;
1924                 cur = btrfs_backup_tree_root_gen(root_backup);
1925                 if (cur == newest_gen)
1926                         newest_index = 0;
1927         }
1928         return newest_index;
1929 }
1930
1931
1932 /*
1933  * find the oldest backup so we know where to store new entries
1934  * in the backup array.  This will set the backup_root_index
1935  * field in the fs_info struct
1936  */
1937 static void find_oldest_super_backup(struct btrfs_fs_info *info,
1938                                      u64 newest_gen)
1939 {
1940         int newest_index = -1;
1941
1942         newest_index = find_newest_super_backup(info, newest_gen);
1943         /* if there was garbage in there, just move along */
1944         if (newest_index == -1) {
1945                 info->backup_root_index = 0;
1946         } else {
1947                 info->backup_root_index = (newest_index + 1) % BTRFS_NUM_BACKUP_ROOTS;
1948         }
1949 }
1950
1951 /*
1952  * copy all the root pointers into the super backup array.
1953  * this will bump the backup pointer by one when it is
1954  * done
1955  */
1956 static void backup_super_roots(struct btrfs_fs_info *info)
1957 {
1958         int next_backup;
1959         struct btrfs_root_backup *root_backup;
1960         int last_backup;
1961
1962         next_backup = info->backup_root_index;
1963         last_backup = (next_backup + BTRFS_NUM_BACKUP_ROOTS - 1) %
1964                 BTRFS_NUM_BACKUP_ROOTS;
1965
1966         /*
1967          * just overwrite the last backup if we're at the same generation
1968          * this happens only at umount
1969          */
1970         root_backup = info->super_for_commit->super_roots + last_backup;
1971         if (btrfs_backup_tree_root_gen(root_backup) ==
1972             btrfs_header_generation(info->tree_root->node))
1973                 next_backup = last_backup;
1974
1975         root_backup = info->super_for_commit->super_roots + next_backup;
1976
1977         /*
1978          * make sure all of our padding and empty slots get zero filled
1979          * regardless of which ones we use today
1980          */
1981         memset(root_backup, 0, sizeof(*root_backup));
1982
1983         info->backup_root_index = (next_backup + 1) % BTRFS_NUM_BACKUP_ROOTS;
1984
1985         btrfs_set_backup_tree_root(root_backup, info->tree_root->node->start);
1986         btrfs_set_backup_tree_root_gen(root_backup,
1987                                btrfs_header_generation(info->tree_root->node));
1988
1989         btrfs_set_backup_tree_root_level(root_backup,
1990                                btrfs_header_level(info->tree_root->node));
1991
1992         btrfs_set_backup_chunk_root(root_backup, info->chunk_root->node->start);
1993         btrfs_set_backup_chunk_root_gen(root_backup,
1994                                btrfs_header_generation(info->chunk_root->node));
1995         btrfs_set_backup_chunk_root_level(root_backup,
1996                                btrfs_header_level(info->chunk_root->node));
1997
1998         btrfs_set_backup_extent_root(root_backup, info->extent_root->node->start);
1999         btrfs_set_backup_extent_root_gen(root_backup,
2000                                btrfs_header_generation(info->extent_root->node));
2001         btrfs_set_backup_extent_root_level(root_backup,
2002                                btrfs_header_level(info->extent_root->node));
2003
2004         /*
2005          * we might commit during log recovery, which happens before we set
2006          * the fs_root.  Make sure it is valid before we fill it in.
2007          */
2008         if (info->fs_root && info->fs_root->node) {
2009                 btrfs_set_backup_fs_root(root_backup,
2010                                          info->fs_root->node->start);
2011                 btrfs_set_backup_fs_root_gen(root_backup,
2012                                btrfs_header_generation(info->fs_root->node));
2013                 btrfs_set_backup_fs_root_level(root_backup,
2014                                btrfs_header_level(info->fs_root->node));
2015         }
2016
2017         btrfs_set_backup_dev_root(root_backup, info->dev_root->node->start);
2018         btrfs_set_backup_dev_root_gen(root_backup,
2019                                btrfs_header_generation(info->dev_root->node));
2020         btrfs_set_backup_dev_root_level(root_backup,
2021                                        btrfs_header_level(info->dev_root->node));
2022
2023         btrfs_set_backup_csum_root(root_backup, info->csum_root->node->start);
2024         btrfs_set_backup_csum_root_gen(root_backup,
2025                                btrfs_header_generation(info->csum_root->node));
2026         btrfs_set_backup_csum_root_level(root_backup,
2027                                btrfs_header_level(info->csum_root->node));
2028
2029         btrfs_set_backup_total_bytes(root_backup,
2030                              btrfs_super_total_bytes(info->super_copy));
2031         btrfs_set_backup_bytes_used(root_backup,
2032                              btrfs_super_bytes_used(info->super_copy));
2033         btrfs_set_backup_num_devices(root_backup,
2034                              btrfs_super_num_devices(info->super_copy));
2035
2036         /*
2037          * if we don't copy this out to the super_copy, it won't get remembered
2038          * for the next commit
2039          */
2040         memcpy(&info->super_copy->super_roots,
2041                &info->super_for_commit->super_roots,
2042                sizeof(*root_backup) * BTRFS_NUM_BACKUP_ROOTS);
2043 }
2044
2045 /*
2046  * this copies info out of the root backup array and back into
2047  * the in-memory super block.  It is meant to help iterate through
2048  * the array, so you send it the number of backups you've already
2049  * tried and the last backup index you used.
2050  *
2051  * this returns -1 when it has tried all the backups
2052  */
2053 static noinline int next_root_backup(struct btrfs_fs_info *info,
2054                                      struct btrfs_super_block *super,
2055                                      int *num_backups_tried, int *backup_index)
2056 {
2057         struct btrfs_root_backup *root_backup;
2058         int newest = *backup_index;
2059
2060         if (*num_backups_tried == 0) {
2061                 u64 gen = btrfs_super_generation(super);
2062
2063                 newest = find_newest_super_backup(info, gen);
2064                 if (newest == -1)
2065                         return -1;
2066
2067                 *backup_index = newest;
2068                 *num_backups_tried = 1;
2069         } else if (*num_backups_tried == BTRFS_NUM_BACKUP_ROOTS) {
2070                 /* we've tried all the backups, all done */
2071                 return -1;
2072         } else {
2073                 /* jump to the next oldest backup */
2074                 newest = (*backup_index + BTRFS_NUM_BACKUP_ROOTS - 1) %
2075                         BTRFS_NUM_BACKUP_ROOTS;
2076                 *backup_index = newest;
2077                 *num_backups_tried += 1;
2078         }
2079         root_backup = super->super_roots + newest;
2080
2081         btrfs_set_super_generation(super,
2082                                    btrfs_backup_tree_root_gen(root_backup));
2083         btrfs_set_super_root(super, btrfs_backup_tree_root(root_backup));
2084         btrfs_set_super_root_level(super,
2085                                    btrfs_backup_tree_root_level(root_backup));
2086         btrfs_set_super_bytes_used(super, btrfs_backup_bytes_used(root_backup));
2087
2088         /*
2089          * fixme: the total bytes and num_devices need to match or we should
2090          * need a fsck
2091          */
2092         btrfs_set_super_total_bytes(super, btrfs_backup_total_bytes(root_backup));
2093         btrfs_set_super_num_devices(super, btrfs_backup_num_devices(root_backup));
2094         return 0;
2095 }
2096
2097 /* helper to cleanup workers */
2098 static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
2099 {
2100         btrfs_destroy_workqueue(fs_info->fixup_workers);
2101         btrfs_destroy_workqueue(fs_info->delalloc_workers);
2102         btrfs_destroy_workqueue(fs_info->workers);
2103         btrfs_destroy_workqueue(fs_info->endio_workers);
2104         btrfs_destroy_workqueue(fs_info->endio_meta_workers);
2105         btrfs_destroy_workqueue(fs_info->endio_raid56_workers);
2106         btrfs_destroy_workqueue(fs_info->endio_repair_workers);
2107         btrfs_destroy_workqueue(fs_info->rmw_workers);
2108         btrfs_destroy_workqueue(fs_info->endio_meta_write_workers);
2109         btrfs_destroy_workqueue(fs_info->endio_write_workers);
2110         btrfs_destroy_workqueue(fs_info->endio_freespace_worker);
2111         btrfs_destroy_workqueue(fs_info->submit_workers);
2112         btrfs_destroy_workqueue(fs_info->delayed_workers);
2113         btrfs_destroy_workqueue(fs_info->caching_workers);
2114         btrfs_destroy_workqueue(fs_info->readahead_workers);
2115         btrfs_destroy_workqueue(fs_info->flush_workers);
2116         btrfs_destroy_workqueue(fs_info->qgroup_rescan_workers);
2117         btrfs_destroy_workqueue(fs_info->extent_workers);
2118 }
2119
2120 static void free_root_extent_buffers(struct btrfs_root *root)
2121 {
2122         if (root) {
2123                 free_extent_buffer(root->node);
2124                 free_extent_buffer(root->commit_root);
2125                 root->node = NULL;
2126                 root->commit_root = NULL;
2127         }
2128 }
2129
2130 /* helper to cleanup tree roots */
2131 static void free_root_pointers(struct btrfs_fs_info *info, int chunk_root)
2132 {
2133         free_root_extent_buffers(info->tree_root);
2134
2135         free_root_extent_buffers(info->dev_root);
2136         free_root_extent_buffers(info->extent_root);
2137         free_root_extent_buffers(info->csum_root);
2138         free_root_extent_buffers(info->quota_root);
2139         free_root_extent_buffers(info->uuid_root);
2140         if (chunk_root)
2141                 free_root_extent_buffers(info->chunk_root);
2142 }
2143
2144 void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info)
2145 {
2146         int ret;
2147         struct btrfs_root *gang[8];
2148         int i;
2149
2150         while (!list_empty(&fs_info->dead_roots)) {
2151                 gang[0] = list_entry(fs_info->dead_roots.next,
2152                                      struct btrfs_root, root_list);
2153                 list_del(&gang[0]->root_list);
2154
2155                 if (test_bit(BTRFS_ROOT_IN_RADIX, &gang[0]->state)) {
2156                         btrfs_drop_and_free_fs_root(fs_info, gang[0]);
2157                 } else {
2158                         free_extent_buffer(gang[0]->node);
2159                         free_extent_buffer(gang[0]->commit_root);
2160                         btrfs_put_fs_root(gang[0]);
2161                 }
2162         }
2163
2164         while (1) {
2165                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2166                                              (void **)gang, 0,
2167                                              ARRAY_SIZE(gang));
2168                 if (!ret)
2169                         break;
2170                 for (i = 0; i < ret; i++)
2171                         btrfs_drop_and_free_fs_root(fs_info, gang[i]);
2172         }
2173
2174         if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
2175                 btrfs_free_log_root_tree(NULL, fs_info);
2176                 btrfs_destroy_pinned_extent(fs_info->tree_root,
2177                                             fs_info->pinned_extents);
2178         }
2179 }
2180
2181 static void btrfs_init_scrub(struct btrfs_fs_info *fs_info)
2182 {
2183         mutex_init(&fs_info->scrub_lock);
2184         atomic_set(&fs_info->scrubs_running, 0);
2185         atomic_set(&fs_info->scrub_pause_req, 0);
2186         atomic_set(&fs_info->scrubs_paused, 0);
2187         atomic_set(&fs_info->scrub_cancel_req, 0);
2188         init_waitqueue_head(&fs_info->scrub_pause_wait);
2189         fs_info->scrub_workers_refcnt = 0;
2190 }
2191
2192 static void btrfs_init_balance(struct btrfs_fs_info *fs_info)
2193 {
2194         spin_lock_init(&fs_info->balance_lock);
2195         mutex_init(&fs_info->balance_mutex);
2196         atomic_set(&fs_info->balance_running, 0);
2197         atomic_set(&fs_info->balance_pause_req, 0);
2198         atomic_set(&fs_info->balance_cancel_req, 0);
2199         fs_info->balance_ctl = NULL;
2200         init_waitqueue_head(&fs_info->balance_wait_q);
2201 }
2202
2203 static void btrfs_init_btree_inode(struct btrfs_fs_info *fs_info,
2204                                    struct btrfs_root *tree_root)
2205 {
2206         fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
2207         set_nlink(fs_info->btree_inode, 1);
2208         /*
2209          * we set the i_size on the btree inode to the max possible int.
2210          * the real end of the address space is determined by all of
2211          * the devices in the system
2212          */
2213         fs_info->btree_inode->i_size = OFFSET_MAX;
2214         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
2215
2216         RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
2217         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
2218                              fs_info->btree_inode->i_mapping);
2219         BTRFS_I(fs_info->btree_inode)->io_tree.track_uptodate = 0;
2220         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree);
2221
2222         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
2223
2224         BTRFS_I(fs_info->btree_inode)->root = tree_root;
2225         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
2226                sizeof(struct btrfs_key));
2227         set_bit(BTRFS_INODE_DUMMY,
2228                 &BTRFS_I(fs_info->btree_inode)->runtime_flags);
2229         btrfs_insert_inode_hash(fs_info->btree_inode);
2230 }
2231
2232 static void btrfs_init_dev_replace_locks(struct btrfs_fs_info *fs_info)
2233 {
2234         fs_info->dev_replace.lock_owner = 0;
2235         atomic_set(&fs_info->dev_replace.nesting_level, 0);
2236         mutex_init(&fs_info->dev_replace.lock_finishing_cancel_unmount);
2237         mutex_init(&fs_info->dev_replace.lock_management_lock);
2238         mutex_init(&fs_info->dev_replace.lock);
2239         init_waitqueue_head(&fs_info->replace_wait);
2240 }
2241
2242 static void btrfs_init_qgroup(struct btrfs_fs_info *fs_info)
2243 {
2244         spin_lock_init(&fs_info->qgroup_lock);
2245         mutex_init(&fs_info->qgroup_ioctl_lock);
2246         fs_info->qgroup_tree = RB_ROOT;
2247         fs_info->qgroup_op_tree = RB_ROOT;
2248         INIT_LIST_HEAD(&fs_info->dirty_qgroups);
2249         fs_info->qgroup_seq = 1;
2250         fs_info->quota_enabled = 0;
2251         fs_info->pending_quota_state = 0;
2252         fs_info->qgroup_ulist = NULL;
2253         mutex_init(&fs_info->qgroup_rescan_lock);
2254 }
2255
2256 static int btrfs_init_workqueues(struct btrfs_fs_info *fs_info,
2257                 struct btrfs_fs_devices *fs_devices)
2258 {
2259         int max_active = fs_info->thread_pool_size;
2260         unsigned int flags = WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_UNBOUND;
2261
2262         fs_info->workers =
2263                 btrfs_alloc_workqueue("worker", flags | WQ_HIGHPRI,
2264                                       max_active, 16);
2265
2266         fs_info->delalloc_workers =
2267                 btrfs_alloc_workqueue("delalloc", flags, max_active, 2);
2268
2269         fs_info->flush_workers =
2270                 btrfs_alloc_workqueue("flush_delalloc", flags, max_active, 0);
2271
2272         fs_info->caching_workers =
2273                 btrfs_alloc_workqueue("cache", flags, max_active, 0);
2274
2275         /*
2276          * a higher idle thresh on the submit workers makes it much more
2277          * likely that bios will be send down in a sane order to the
2278          * devices
2279          */
2280         fs_info->submit_workers =
2281                 btrfs_alloc_workqueue("submit", flags,
2282                                       min_t(u64, fs_devices->num_devices,
2283                                             max_active), 64);
2284
2285         fs_info->fixup_workers =
2286                 btrfs_alloc_workqueue("fixup", flags, 1, 0);
2287
2288         /*
2289          * endios are largely parallel and should have a very
2290          * low idle thresh
2291          */
2292         fs_info->endio_workers =
2293                 btrfs_alloc_workqueue("endio", flags, max_active, 4);
2294         fs_info->endio_meta_workers =
2295                 btrfs_alloc_workqueue("endio-meta", flags, max_active, 4);
2296         fs_info->endio_meta_write_workers =
2297                 btrfs_alloc_workqueue("endio-meta-write", flags, max_active, 2);
2298         fs_info->endio_raid56_workers =
2299                 btrfs_alloc_workqueue("endio-raid56", flags, max_active, 4);
2300         fs_info->endio_repair_workers =
2301                 btrfs_alloc_workqueue("endio-repair", flags, 1, 0);
2302         fs_info->rmw_workers =
2303                 btrfs_alloc_workqueue("rmw", flags, max_active, 2);
2304         fs_info->endio_write_workers =
2305                 btrfs_alloc_workqueue("endio-write", flags, max_active, 2);
2306         fs_info->endio_freespace_worker =
2307                 btrfs_alloc_workqueue("freespace-write", flags, max_active, 0);
2308         fs_info->delayed_workers =
2309                 btrfs_alloc_workqueue("delayed-meta", flags, max_active, 0);
2310         fs_info->readahead_workers =
2311                 btrfs_alloc_workqueue("readahead", flags, max_active, 2);
2312         fs_info->qgroup_rescan_workers =
2313                 btrfs_alloc_workqueue("qgroup-rescan", flags, 1, 0);
2314         fs_info->extent_workers =
2315                 btrfs_alloc_workqueue("extent-refs", flags,
2316                                       min_t(u64, fs_devices->num_devices,
2317                                             max_active), 8);
2318
2319         if (!(fs_info->workers && fs_info->delalloc_workers &&
2320               fs_info->submit_workers && fs_info->flush_workers &&
2321               fs_info->endio_workers && fs_info->endio_meta_workers &&
2322               fs_info->endio_meta_write_workers &&
2323               fs_info->endio_repair_workers &&
2324               fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
2325               fs_info->endio_freespace_worker && fs_info->rmw_workers &&
2326               fs_info->caching_workers && fs_info->readahead_workers &&
2327               fs_info->fixup_workers && fs_info->delayed_workers &&
2328               fs_info->extent_workers &&
2329               fs_info->qgroup_rescan_workers)) {
2330                 return -ENOMEM;
2331         }
2332
2333         return 0;
2334 }
2335
2336 static int btrfs_replay_log(struct btrfs_fs_info *fs_info,
2337                             struct btrfs_fs_devices *fs_devices)
2338 {
2339         int ret;
2340         struct btrfs_root *tree_root = fs_info->tree_root;
2341         struct btrfs_root *log_tree_root;
2342         struct btrfs_super_block *disk_super = fs_info->super_copy;
2343         u64 bytenr = btrfs_super_log_root(disk_super);
2344
2345         if (fs_devices->rw_devices == 0) {
2346                 printk(KERN_WARNING "BTRFS: log replay required "
2347                        "on RO media\n");
2348                 return -EIO;
2349         }
2350
2351         log_tree_root = btrfs_alloc_root(fs_info);
2352         if (!log_tree_root)
2353                 return -ENOMEM;
2354
2355         __setup_root(tree_root->nodesize, tree_root->sectorsize,
2356                         tree_root->stripesize, log_tree_root, fs_info,
2357                         BTRFS_TREE_LOG_OBJECTID);
2358
2359         log_tree_root->node = read_tree_block(tree_root, bytenr,
2360                         fs_info->generation + 1);
2361         if (IS_ERR(log_tree_root->node)) {
2362                 printk(KERN_ERR "BTRFS: failed to read log tree\n");
2363                 ret = PTR_ERR(log_tree_root->node);
2364                 kfree(log_tree_root);
2365                 return ret;
2366         } else if (!extent_buffer_uptodate(log_tree_root->node)) {
2367                 printk(KERN_ERR "BTRFS: failed to read log tree\n");
2368                 free_extent_buffer(log_tree_root->node);
2369                 kfree(log_tree_root);
2370                 return -EIO;
2371         }
2372         /* returns with log_tree_root freed on success */
2373         ret = btrfs_recover_log_trees(log_tree_root);
2374         if (ret) {
2375                 btrfs_error(tree_root->fs_info, ret,
2376                             "Failed to recover log tree");
2377                 free_extent_buffer(log_tree_root->node);
2378                 kfree(log_tree_root);
2379                 return ret;
2380         }
2381
2382         if (fs_info->sb->s_flags & MS_RDONLY) {
2383                 ret = btrfs_commit_super(tree_root);
2384                 if (ret)
2385                         return ret;
2386         }
2387
2388         return 0;
2389 }
2390
2391 static int btrfs_read_roots(struct btrfs_fs_info *fs_info,
2392                             struct btrfs_root *tree_root)
2393 {
2394         struct btrfs_root *root;
2395         struct btrfs_key location;
2396         int ret;
2397
2398         location.objectid = BTRFS_EXTENT_TREE_OBJECTID;
2399         location.type = BTRFS_ROOT_ITEM_KEY;
2400         location.offset = 0;
2401
2402         root = btrfs_read_tree_root(tree_root, &location);
2403         if (IS_ERR(root))
2404                 return PTR_ERR(root);
2405         set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2406         fs_info->extent_root = root;
2407
2408         location.objectid = BTRFS_DEV_TREE_OBJECTID;
2409         root = btrfs_read_tree_root(tree_root, &location);
2410         if (IS_ERR(root))
2411                 return PTR_ERR(root);
2412         set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2413         fs_info->dev_root = root;
2414         btrfs_init_devices_late(fs_info);
2415
2416         location.objectid = BTRFS_CSUM_TREE_OBJECTID;
2417         root = btrfs_read_tree_root(tree_root, &location);
2418         if (IS_ERR(root))
2419                 return PTR_ERR(root);
2420         set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2421         fs_info->csum_root = root;
2422
2423         location.objectid = BTRFS_QUOTA_TREE_OBJECTID;
2424         root = btrfs_read_tree_root(tree_root, &location);
2425         if (!IS_ERR(root)) {
2426                 set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2427                 fs_info->quota_enabled = 1;
2428                 fs_info->pending_quota_state = 1;
2429                 fs_info->quota_root = root;
2430         }
2431
2432         location.objectid = BTRFS_UUID_TREE_OBJECTID;
2433         root = btrfs_read_tree_root(tree_root, &location);
2434         if (IS_ERR(root)) {
2435                 ret = PTR_ERR(root);
2436                 if (ret != -ENOENT)
2437                         return ret;
2438         } else {
2439                 set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2440                 fs_info->uuid_root = root;
2441         }
2442
2443         return 0;
2444 }
2445
2446 int open_ctree(struct super_block *sb,
2447                struct btrfs_fs_devices *fs_devices,
2448                char *options)
2449 {
2450         u32 sectorsize;
2451         u32 nodesize;
2452         u32 stripesize;
2453         u64 generation;
2454         u64 features;
2455         struct btrfs_key location;
2456         struct buffer_head *bh;
2457         struct btrfs_super_block *disk_super;
2458         struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2459         struct btrfs_root *tree_root;
2460         struct btrfs_root *chunk_root;
2461         int ret;
2462         int err = -EINVAL;
2463         int num_backups_tried = 0;
2464         int backup_index = 0;
2465         int max_active;
2466
2467         tree_root = fs_info->tree_root = btrfs_alloc_root(fs_info);
2468         chunk_root = fs_info->chunk_root = btrfs_alloc_root(fs_info);
2469         if (!tree_root || !chunk_root) {
2470                 err = -ENOMEM;
2471                 goto fail;
2472         }
2473
2474         ret = init_srcu_struct(&fs_info->subvol_srcu);
2475         if (ret) {
2476                 err = ret;
2477                 goto fail;
2478         }
2479
2480         ret = setup_bdi(fs_info, &fs_info->bdi);
2481         if (ret) {
2482                 err = ret;
2483                 goto fail_srcu;
2484         }
2485
2486         ret = percpu_counter_init(&fs_info->dirty_metadata_bytes, 0, GFP_KERNEL);
2487         if (ret) {
2488                 err = ret;
2489                 goto fail_bdi;
2490         }
2491         fs_info->dirty_metadata_batch = PAGE_CACHE_SIZE *
2492                                         (1 + ilog2(nr_cpu_ids));
2493
2494         ret = percpu_counter_init(&fs_info->delalloc_bytes, 0, GFP_KERNEL);
2495         if (ret) {
2496                 err = ret;
2497                 goto fail_dirty_metadata_bytes;
2498         }
2499
2500         ret = percpu_counter_init(&fs_info->bio_counter, 0, GFP_KERNEL);
2501         if (ret) {
2502                 err = ret;
2503                 goto fail_delalloc_bytes;
2504         }
2505
2506         fs_info->btree_inode = new_inode(sb);
2507         if (!fs_info->btree_inode) {
2508                 err = -ENOMEM;
2509                 goto fail_bio_counter;
2510         }
2511
2512         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
2513
2514         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
2515         INIT_RADIX_TREE(&fs_info->buffer_radix, GFP_ATOMIC);
2516         INIT_LIST_HEAD(&fs_info->trans_list);
2517         INIT_LIST_HEAD(&fs_info->dead_roots);
2518         INIT_LIST_HEAD(&fs_info->delayed_iputs);
2519         INIT_LIST_HEAD(&fs_info->delalloc_roots);
2520         INIT_LIST_HEAD(&fs_info->caching_block_groups);
2521         spin_lock_init(&fs_info->delalloc_root_lock);
2522         spin_lock_init(&fs_info->trans_lock);
2523         spin_lock_init(&fs_info->fs_roots_radix_lock);
2524         spin_lock_init(&fs_info->delayed_iput_lock);
2525         spin_lock_init(&fs_info->defrag_inodes_lock);
2526         spin_lock_init(&fs_info->free_chunk_lock);
2527         spin_lock_init(&fs_info->tree_mod_seq_lock);
2528         spin_lock_init(&fs_info->super_lock);
2529         spin_lock_init(&fs_info->qgroup_op_lock);
2530         spin_lock_init(&fs_info->buffer_lock);
2531         spin_lock_init(&fs_info->unused_bgs_lock);
2532         rwlock_init(&fs_info->tree_mod_log_lock);
2533         mutex_init(&fs_info->unused_bg_unpin_mutex);
2534         mutex_init(&fs_info->delete_unused_bgs_mutex);
2535         mutex_init(&fs_info->reloc_mutex);
2536         mutex_init(&fs_info->delalloc_root_mutex);
2537         seqlock_init(&fs_info->profiles_lock);
2538         init_rwsem(&fs_info->delayed_iput_sem);
2539
2540         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
2541         INIT_LIST_HEAD(&fs_info->space_info);
2542         INIT_LIST_HEAD(&fs_info->tree_mod_seq_list);
2543         INIT_LIST_HEAD(&fs_info->unused_bgs);
2544         btrfs_mapping_init(&fs_info->mapping_tree);
2545         btrfs_init_block_rsv(&fs_info->global_block_rsv,
2546                              BTRFS_BLOCK_RSV_GLOBAL);
2547         btrfs_init_block_rsv(&fs_info->delalloc_block_rsv,
2548                              BTRFS_BLOCK_RSV_DELALLOC);
2549         btrfs_init_block_rsv(&fs_info->trans_block_rsv, BTRFS_BLOCK_RSV_TRANS);
2550         btrfs_init_block_rsv(&fs_info->chunk_block_rsv, BTRFS_BLOCK_RSV_CHUNK);
2551         btrfs_init_block_rsv(&fs_info->empty_block_rsv, BTRFS_BLOCK_RSV_EMPTY);
2552         btrfs_init_block_rsv(&fs_info->delayed_block_rsv,
2553                              BTRFS_BLOCK_RSV_DELOPS);
2554         atomic_set(&fs_info->nr_async_submits, 0);
2555         atomic_set(&fs_info->async_delalloc_pages, 0);
2556         atomic_set(&fs_info->async_submit_draining, 0);
2557         atomic_set(&fs_info->nr_async_bios, 0);
2558         atomic_set(&fs_info->defrag_running, 0);
2559         atomic_set(&fs_info->qgroup_op_seq, 0);
2560         atomic64_set(&fs_info->tree_mod_seq, 0);
2561         fs_info->sb = sb;
2562         fs_info->max_inline = BTRFS_DEFAULT_MAX_INLINE;
2563         fs_info->metadata_ratio = 0;
2564         fs_info->defrag_inodes = RB_ROOT;
2565         fs_info->free_chunk_space = 0;
2566         fs_info->tree_mod_log = RB_ROOT;
2567         fs_info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
2568         fs_info->avg_delayed_ref_runtime = NSEC_PER_SEC >> 6; /* div by 64 */
2569         /* readahead state */
2570         INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_WAIT);
2571         spin_lock_init(&fs_info->reada_lock);
2572
2573         fs_info->thread_pool_size = min_t(unsigned long,
2574                                           num_online_cpus() + 2, 8);
2575
2576         INIT_LIST_HEAD(&fs_info->ordered_roots);
2577         spin_lock_init(&fs_info->ordered_root_lock);
2578         fs_info->delayed_root = kmalloc(sizeof(struct btrfs_delayed_root),
2579                                         GFP_NOFS);
2580         if (!fs_info->delayed_root) {
2581                 err = -ENOMEM;
2582                 goto fail_iput;
2583         }
2584         btrfs_init_delayed_root(fs_info->delayed_root);
2585
2586         btrfs_init_scrub(fs_info);
2587 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2588         fs_info->check_integrity_print_mask = 0;
2589 #endif
2590         btrfs_init_balance(fs_info);
2591         btrfs_init_async_reclaim_work(&fs_info->async_reclaim_work);
2592
2593         sb->s_blocksize = 4096;
2594         sb->s_blocksize_bits = blksize_bits(4096);
2595         sb->s_bdi = &fs_info->bdi;
2596
2597         btrfs_init_btree_inode(fs_info, tree_root);
2598
2599         spin_lock_init(&fs_info->block_group_cache_lock);
2600         fs_info->block_group_cache_tree = RB_ROOT;
2601         fs_info->first_logical_byte = (u64)-1;
2602
2603         extent_io_tree_init(&fs_info->freed_extents[0],
2604                              fs_info->btree_inode->i_mapping);
2605         extent_io_tree_init(&fs_info->freed_extents[1],
2606                              fs_info->btree_inode->i_mapping);
2607         fs_info->pinned_extents = &fs_info->freed_extents[0];
2608         fs_info->do_barriers = 1;
2609
2610
2611         mutex_init(&fs_info->ordered_operations_mutex);
2612         mutex_init(&fs_info->tree_log_mutex);
2613         mutex_init(&fs_info->chunk_mutex);
2614         mutex_init(&fs_info->transaction_kthread_mutex);
2615         mutex_init(&fs_info->cleaner_mutex);
2616         mutex_init(&fs_info->volume_mutex);
2617         mutex_init(&fs_info->ro_block_group_mutex);
2618         init_rwsem(&fs_info->commit_root_sem);
2619         init_rwsem(&fs_info->cleanup_work_sem);
2620         init_rwsem(&fs_info->subvol_sem);
2621         sema_init(&fs_info->uuid_tree_rescan_sem, 1);
2622
2623         btrfs_init_dev_replace_locks(fs_info);
2624         btrfs_init_qgroup(fs_info);
2625
2626         btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
2627         btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
2628
2629         init_waitqueue_head(&fs_info->transaction_throttle);
2630         init_waitqueue_head(&fs_info->transaction_wait);
2631         init_waitqueue_head(&fs_info->transaction_blocked_wait);
2632         init_waitqueue_head(&fs_info->async_submit_wait);
2633
2634         INIT_LIST_HEAD(&fs_info->pinned_chunks);
2635
2636         ret = btrfs_alloc_stripe_hash_table(fs_info);
2637         if (ret) {
2638                 err = ret;
2639                 goto fail_alloc;
2640         }
2641
2642         __setup_root(4096, 4096, 4096, tree_root,
2643                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
2644
2645         invalidate_bdev(fs_devices->latest_bdev);
2646
2647         /*
2648          * Read super block and check the signature bytes only
2649          */
2650         bh = btrfs_read_dev_super(fs_devices->latest_bdev);
2651         if (!bh) {
2652                 err = -EINVAL;
2653                 goto fail_alloc;
2654         }
2655
2656         /*
2657          * We want to check superblock checksum, the type is stored inside.
2658          * Pass the whole disk block of size BTRFS_SUPER_INFO_SIZE (4k).
2659          */
2660         if (btrfs_check_super_csum(bh->b_data)) {
2661                 printk(KERN_ERR "BTRFS: superblock checksum mismatch\n");
2662                 err = -EINVAL;
2663                 goto fail_alloc;
2664         }
2665
2666         /*
2667          * super_copy is zeroed at allocation time and we never touch the
2668          * following bytes up to INFO_SIZE, the checksum is calculated from
2669          * the whole block of INFO_SIZE
2670          */
2671         memcpy(fs_info->super_copy, bh->b_data, sizeof(*fs_info->super_copy));
2672         memcpy(fs_info->super_for_commit, fs_info->super_copy,
2673                sizeof(*fs_info->super_for_commit));
2674         brelse(bh);
2675
2676         memcpy(fs_info->fsid, fs_info->super_copy->fsid, BTRFS_FSID_SIZE);
2677
2678         ret = btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
2679         if (ret) {
2680                 printk(KERN_ERR "BTRFS: superblock contains fatal errors\n");
2681                 err = -EINVAL;
2682                 goto fail_alloc;
2683         }
2684
2685         disk_super = fs_info->super_copy;
2686         if (!btrfs_super_root(disk_super))
2687                 goto fail_alloc;
2688
2689         /* check FS state, whether FS is broken. */
2690         if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_ERROR)
2691                 set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
2692
2693         /*
2694          * run through our array of backup supers and setup
2695          * our ring pointer to the oldest one
2696          */
2697         generation = btrfs_super_generation(disk_super);
2698         find_oldest_super_backup(fs_info, generation);
2699
2700         /*
2701          * In the long term, we'll store the compression type in the super
2702          * block, and it'll be used for per file compression control.
2703          */
2704         fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
2705
2706         ret = btrfs_parse_options(tree_root, options);
2707         if (ret) {
2708                 err = ret;
2709                 goto fail_alloc;
2710         }
2711
2712         features = btrfs_super_incompat_flags(disk_super) &
2713                 ~BTRFS_FEATURE_INCOMPAT_SUPP;
2714         if (features) {
2715                 printk(KERN_ERR "BTRFS: couldn't mount because of "
2716                        "unsupported optional features (%Lx).\n",
2717                        features);
2718                 err = -EINVAL;
2719                 goto fail_alloc;
2720         }
2721
2722         /*
2723          * Leafsize and nodesize were always equal, this is only a sanity check.
2724          */
2725         if (le32_to_cpu(disk_super->__unused_leafsize) !=
2726             btrfs_super_nodesize(disk_super)) {
2727                 printk(KERN_ERR "BTRFS: couldn't mount because metadata "
2728                        "blocksizes don't match.  node %d leaf %d\n",
2729                        btrfs_super_nodesize(disk_super),
2730                        le32_to_cpu(disk_super->__unused_leafsize));
2731                 err = -EINVAL;
2732                 goto fail_alloc;
2733         }
2734         if (btrfs_super_nodesize(disk_super) > BTRFS_MAX_METADATA_BLOCKSIZE) {
2735                 printk(KERN_ERR "BTRFS: couldn't mount because metadata "
2736                        "blocksize (%d) was too large\n",
2737                        btrfs_super_nodesize(disk_super));
2738                 err = -EINVAL;
2739                 goto fail_alloc;
2740         }
2741
2742         features = btrfs_super_incompat_flags(disk_super);
2743         features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
2744         if (tree_root->fs_info->compress_type == BTRFS_COMPRESS_LZO)
2745                 features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
2746
2747         if (features & BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)
2748                 printk(KERN_INFO "BTRFS: has skinny extents\n");
2749
2750         /*
2751          * flag our filesystem as having big metadata blocks if
2752          * they are bigger than the page size
2753          */
2754         if (btrfs_super_nodesize(disk_super) > PAGE_CACHE_SIZE) {
2755                 if (!(features & BTRFS_FEATURE_INCOMPAT_BIG_METADATA))
2756                         printk(KERN_INFO "BTRFS: flagging fs with big metadata feature\n");
2757                 features |= BTRFS_FEATURE_INCOMPAT_BIG_METADATA;
2758         }
2759
2760         nodesize = btrfs_super_nodesize(disk_super);
2761         sectorsize = btrfs_super_sectorsize(disk_super);
2762         stripesize = btrfs_super_stripesize(disk_super);
2763         fs_info->dirty_metadata_batch = nodesize * (1 + ilog2(nr_cpu_ids));
2764         fs_info->delalloc_batch = sectorsize * 512 * (1 + ilog2(nr_cpu_ids));
2765
2766         /*
2767          * mixed block groups end up with duplicate but slightly offset
2768          * extent buffers for the same range.  It leads to corruptions
2769          */
2770         if ((features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS) &&
2771             (sectorsize != nodesize)) {
2772                 printk(KERN_ERR "BTRFS: unequal leaf/node/sector sizes "
2773                                 "are not allowed for mixed block groups on %s\n",
2774                                 sb->s_id);
2775                 goto fail_alloc;
2776         }
2777
2778         /*
2779          * Needn't use the lock because there is no other task which will
2780          * update the flag.
2781          */
2782         btrfs_set_super_incompat_flags(disk_super, features);
2783
2784         features = btrfs_super_compat_ro_flags(disk_super) &
2785                 ~BTRFS_FEATURE_COMPAT_RO_SUPP;
2786         if (!(sb->s_flags & MS_RDONLY) && features) {
2787                 printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
2788                        "unsupported option features (%Lx).\n",
2789                        features);
2790                 err = -EINVAL;
2791                 goto fail_alloc;
2792         }
2793
2794         max_active = fs_info->thread_pool_size;
2795
2796         ret = btrfs_init_workqueues(fs_info, fs_devices);
2797         if (ret) {
2798                 err = ret;
2799                 goto fail_sb_buffer;
2800         }
2801
2802         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
2803         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
2804                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
2805
2806         tree_root->nodesize = nodesize;
2807         tree_root->sectorsize = sectorsize;
2808         tree_root->stripesize = stripesize;
2809
2810         sb->s_blocksize = sectorsize;
2811         sb->s_blocksize_bits = blksize_bits(sectorsize);
2812
2813         if (btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
2814                 printk(KERN_ERR "BTRFS: valid FS not found on %s\n", sb->s_id);
2815                 goto fail_sb_buffer;
2816         }
2817
2818         if (sectorsize != PAGE_SIZE) {
2819                 printk(KERN_ERR "BTRFS: incompatible sector size (%lu) "
2820                        "found on %s\n", (unsigned long)sectorsize, sb->s_id);
2821                 goto fail_sb_buffer;
2822         }
2823
2824         mutex_lock(&fs_info->chunk_mutex);
2825         ret = btrfs_read_sys_array(tree_root);
2826         mutex_unlock(&fs_info->chunk_mutex);
2827         if (ret) {
2828                 printk(KERN_ERR "BTRFS: failed to read the system "
2829                        "array on %s\n", sb->s_id);
2830                 goto fail_sb_buffer;
2831         }
2832
2833         generation = btrfs_super_chunk_root_generation(disk_super);
2834
2835         __setup_root(nodesize, sectorsize, stripesize, chunk_root,
2836                      fs_info, BTRFS_CHUNK_TREE_OBJECTID);
2837
2838         chunk_root->node = read_tree_block(chunk_root,
2839                                            btrfs_super_chunk_root(disk_super),
2840                                            generation);
2841         if (IS_ERR(chunk_root->node) ||
2842             !extent_buffer_uptodate(chunk_root->node)) {
2843                 printk(KERN_ERR "BTRFS: failed to read chunk root on %s\n",
2844                        sb->s_id);
2845                 chunk_root->node = NULL;
2846                 goto fail_tree_roots;
2847         }
2848         btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
2849         chunk_root->commit_root = btrfs_root_node(chunk_root);
2850
2851         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
2852            btrfs_header_chunk_tree_uuid(chunk_root->node), BTRFS_UUID_SIZE);
2853
2854         ret = btrfs_read_chunk_tree(chunk_root);
2855         if (ret) {
2856                 printk(KERN_ERR "BTRFS: failed to read chunk tree on %s\n",
2857                        sb->s_id);
2858                 goto fail_tree_roots;
2859         }
2860
2861         /*
2862          * keep the device that is marked to be the target device for the
2863          * dev_replace procedure
2864          */
2865         btrfs_close_extra_devices(fs_devices, 0);
2866
2867         if (!fs_devices->latest_bdev) {
2868                 printk(KERN_ERR "BTRFS: failed to read devices on %s\n",
2869                        sb->s_id);
2870                 goto fail_tree_roots;
2871         }
2872
2873 retry_root_backup:
2874         generation = btrfs_super_generation(disk_super);
2875
2876         tree_root->node = read_tree_block(tree_root,
2877                                           btrfs_super_root(disk_super),
2878                                           generation);
2879         if (IS_ERR(tree_root->node) ||
2880             !extent_buffer_uptodate(tree_root->node)) {
2881                 printk(KERN_WARNING "BTRFS: failed to read tree root on %s\n",
2882                        sb->s_id);
2883                 tree_root->node = NULL;
2884                 goto recovery_tree_root;
2885         }
2886
2887         btrfs_set_root_node(&tree_root->root_item, tree_root->node);
2888         tree_root->commit_root = btrfs_root_node(tree_root);
2889         btrfs_set_root_refs(&tree_root->root_item, 1);
2890
2891         ret = btrfs_read_roots(fs_info, tree_root);
2892         if (ret)
2893                 goto recovery_tree_root;
2894
2895         fs_info->generation = generation;
2896         fs_info->last_trans_committed = generation;
2897
2898         ret = btrfs_recover_balance(fs_info);
2899         if (ret) {
2900                 printk(KERN_ERR "BTRFS: failed to recover balance\n");
2901                 goto fail_block_groups;
2902         }
2903
2904         ret = btrfs_init_dev_stats(fs_info);
2905         if (ret) {
2906                 printk(KERN_ERR "BTRFS: failed to init dev_stats: %d\n",
2907                        ret);
2908                 goto fail_block_groups;
2909         }
2910
2911         ret = btrfs_init_dev_replace(fs_info);
2912         if (ret) {
2913                 pr_err("BTRFS: failed to init dev_replace: %d\n", ret);
2914                 goto fail_block_groups;
2915         }
2916
2917         btrfs_close_extra_devices(fs_devices, 1);
2918
2919         ret = btrfs_sysfs_add_fsid(fs_devices, NULL);
2920         if (ret) {
2921                 pr_err("BTRFS: failed to init sysfs fsid interface: %d\n", ret);
2922                 goto fail_block_groups;
2923         }
2924
2925         ret = btrfs_sysfs_add_device(fs_devices);
2926         if (ret) {
2927                 pr_err("BTRFS: failed to init sysfs device interface: %d\n", ret);
2928                 goto fail_fsdev_sysfs;
2929         }
2930
2931         ret = btrfs_sysfs_add_one(fs_info);
2932         if (ret) {
2933                 pr_err("BTRFS: failed to init sysfs interface: %d\n", ret);
2934                 goto fail_fsdev_sysfs;
2935         }
2936
2937         ret = btrfs_init_space_info(fs_info);
2938         if (ret) {
2939                 printk(KERN_ERR "BTRFS: Failed to initial space info: %d\n", ret);
2940                 goto fail_sysfs;
2941         }
2942
2943         ret = btrfs_read_block_groups(fs_info->extent_root);
2944         if (ret) {
2945                 printk(KERN_ERR "BTRFS: Failed to read block groups: %d\n", ret);
2946                 goto fail_sysfs;
2947         }
2948         fs_info->num_tolerated_disk_barrier_failures =
2949                 btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
2950         if (fs_info->fs_devices->missing_devices >
2951              fs_info->num_tolerated_disk_barrier_failures &&
2952             !(sb->s_flags & MS_RDONLY)) {
2953                 pr_warn("BTRFS: missing devices(%llu) exceeds the limit(%d), writeable mount is not allowed\n",
2954                         fs_info->fs_devices->missing_devices,
2955                         fs_info->num_tolerated_disk_barrier_failures);
2956                 goto fail_sysfs;
2957         }
2958
2959         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
2960                                                "btrfs-cleaner");
2961         if (IS_ERR(fs_info->cleaner_kthread))
2962                 goto fail_sysfs;
2963
2964         fs_info->transaction_kthread = kthread_run(transaction_kthread,
2965                                                    tree_root,
2966                                                    "btrfs-transaction");
2967         if (IS_ERR(fs_info->transaction_kthread))
2968                 goto fail_cleaner;
2969
2970         if (!btrfs_test_opt(tree_root, SSD) &&
2971             !btrfs_test_opt(tree_root, NOSSD) &&
2972             !fs_info->fs_devices->rotating) {
2973                 printk(KERN_INFO "BTRFS: detected SSD devices, enabling SSD "
2974                        "mode\n");
2975                 btrfs_set_opt(fs_info->mount_opt, SSD);
2976         }
2977
2978         /*
2979          * Mount does not set all options immediatelly, we can do it now and do
2980          * not have to wait for transaction commit
2981          */
2982         btrfs_apply_pending_changes(fs_info);
2983
2984 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2985         if (btrfs_test_opt(tree_root, CHECK_INTEGRITY)) {
2986                 ret = btrfsic_mount(tree_root, fs_devices,
2987                                     btrfs_test_opt(tree_root,
2988                                         CHECK_INTEGRITY_INCLUDING_EXTENT_DATA) ?
2989                                     1 : 0,
2990                                     fs_info->check_integrity_print_mask);
2991                 if (ret)
2992                         printk(KERN_WARNING "BTRFS: failed to initialize"
2993                                " integrity check module %s\n", sb->s_id);
2994         }
2995 #endif
2996         ret = btrfs_read_qgroup_config(fs_info);
2997         if (ret)
2998                 goto fail_trans_kthread;
2999
3000         /* do not make disk changes in broken FS */
3001         if (btrfs_super_log_root(disk_super) != 0) {
3002                 ret = btrfs_replay_log(fs_info, fs_devices);
3003                 if (ret) {
3004                         err = ret;
3005                         goto fail_qgroup;
3006                 }
3007         }
3008
3009         ret = btrfs_find_orphan_roots(tree_root);
3010         if (ret)
3011                 goto fail_qgroup;
3012
3013         if (!(sb->s_flags & MS_RDONLY)) {
3014                 ret = btrfs_cleanup_fs_roots(fs_info);
3015                 if (ret)
3016                         goto fail_qgroup;
3017
3018                 mutex_lock(&fs_info->cleaner_mutex);
3019                 ret = btrfs_recover_relocation(tree_root);
3020                 mutex_unlock(&fs_info->cleaner_mutex);
3021                 if (ret < 0) {
3022                         printk(KERN_WARNING
3023                                "BTRFS: failed to recover relocation\n");
3024                         err = -EINVAL;
3025                         goto fail_qgroup;
3026                 }
3027         }
3028
3029         location.objectid = BTRFS_FS_TREE_OBJECTID;
3030         location.type = BTRFS_ROOT_ITEM_KEY;
3031         location.offset = 0;
3032
3033         fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
3034         if (IS_ERR(fs_info->fs_root)) {
3035                 err = PTR_ERR(fs_info->fs_root);
3036                 goto fail_qgroup;
3037         }
3038
3039         if (sb->s_flags & MS_RDONLY)
3040                 return 0;
3041
3042         down_read(&fs_info->cleanup_work_sem);
3043         if ((ret = btrfs_orphan_cleanup(fs_info->fs_root)) ||
3044             (ret = btrfs_orphan_cleanup(fs_info->tree_root))) {
3045                 up_read(&fs_info->cleanup_work_sem);
3046                 close_ctree(tree_root);
3047                 return ret;
3048         }
3049         up_read(&fs_info->cleanup_work_sem);
3050
3051         ret = btrfs_resume_balance_async(fs_info);
3052         if (ret) {
3053                 printk(KERN_WARNING "BTRFS: failed to resume balance\n");
3054                 close_ctree(tree_root);
3055                 return ret;
3056         }
3057
3058         ret = btrfs_resume_dev_replace_async(fs_info);
3059         if (ret) {
3060                 pr_warn("BTRFS: failed to resume dev_replace\n");
3061                 close_ctree(tree_root);
3062                 return ret;
3063         }
3064
3065         btrfs_qgroup_rescan_resume(fs_info);
3066
3067         if (!fs_info->uuid_root) {
3068                 pr_info("BTRFS: creating UUID tree\n");
3069                 ret = btrfs_create_uuid_tree(fs_info);
3070                 if (ret) {
3071                         pr_warn("BTRFS: failed to create the UUID tree %d\n",
3072                                 ret);
3073                         close_ctree(tree_root);
3074                         return ret;
3075                 }
3076         } else if (btrfs_test_opt(tree_root, RESCAN_UUID_TREE) ||
3077                    fs_info->generation !=
3078                                 btrfs_super_uuid_tree_generation(disk_super)) {
3079                 pr_info("BTRFS: checking UUID tree\n");
3080                 ret = btrfs_check_uuid_tree(fs_info);
3081                 if (ret) {
3082                         pr_warn("BTRFS: failed to check the UUID tree %d\n",
3083                                 ret);
3084                         close_ctree(tree_root);
3085                         return ret;
3086                 }
3087         } else {
3088                 fs_info->update_uuid_tree_gen = 1;
3089         }
3090
3091         fs_info->open = 1;
3092
3093         return 0;
3094
3095 fail_qgroup:
3096         btrfs_free_qgroup_config(fs_info);
3097 fail_trans_kthread:
3098         kthread_stop(fs_info->transaction_kthread);
3099         btrfs_cleanup_transaction(fs_info->tree_root);
3100         btrfs_free_fs_roots(fs_info);
3101 fail_cleaner:
3102         kthread_stop(fs_info->cleaner_kthread);
3103
3104         /*
3105          * make sure we're done with the btree inode before we stop our
3106          * kthreads
3107          */
3108         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
3109
3110 fail_sysfs:
3111         btrfs_sysfs_remove_one(fs_info);
3112
3113 fail_fsdev_sysfs:
3114         btrfs_sysfs_remove_fsid(fs_info->fs_devices);
3115
3116 fail_block_groups:
3117         btrfs_put_block_group_cache(fs_info);
3118         btrfs_free_block_groups(fs_info);
3119
3120 fail_tree_roots:
3121         free_root_pointers(fs_info, 1);
3122         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
3123
3124 fail_sb_buffer:
3125         btrfs_stop_all_workers(fs_info);
3126 fail_alloc:
3127 fail_iput:
3128         btrfs_mapping_tree_free(&fs_info->mapping_tree);
3129
3130         iput(fs_info->btree_inode);
3131 fail_bio_counter:
3132         percpu_counter_destroy(&fs_info->bio_counter);
3133 fail_delalloc_bytes:
3134         percpu_counter_destroy(&fs_info->delalloc_bytes);
3135 fail_dirty_metadata_bytes:
3136         percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
3137 fail_bdi:
3138         bdi_destroy(&fs_info->bdi);
3139 fail_srcu:
3140         cleanup_srcu_struct(&fs_info->subvol_srcu);
3141 fail:
3142         btrfs_free_stripe_hash_table(fs_info);
3143         btrfs_close_devices(fs_info->fs_devices);
3144         return err;
3145
3146 recovery_tree_root:
3147         if (!btrfs_test_opt(tree_root, RECOVERY))
3148                 goto fail_tree_roots;
3149
3150         free_root_pointers(fs_info, 0);
3151
3152         /* don't use the log in recovery mode, it won't be valid */
3153         btrfs_set_super_log_root(disk_super, 0);
3154
3155         /* we can't trust the free space cache either */
3156         btrfs_set_opt(fs_info->mount_opt, CLEAR_CACHE);
3157
3158         ret = next_root_backup(fs_info, fs_info->super_copy,
3159                                &num_backups_tried, &backup_index);
3160         if (ret == -1)
3161                 goto fail_block_groups;
3162         goto retry_root_backup;
3163 }
3164
3165 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
3166 {
3167         if (uptodate) {
3168                 set_buffer_uptodate(bh);
3169         } else {
3170                 struct btrfs_device *device = (struct btrfs_device *)
3171                         bh->b_private;
3172
3173                 printk_ratelimited_in_rcu(KERN_WARNING "BTRFS: lost page write due to "
3174                                           "I/O error on %s\n",
3175                                           rcu_str_deref(device->name));
3176                 /* note, we dont' set_buffer_write_io_error because we have
3177                  * our own ways of dealing with the IO errors
3178                  */
3179                 clear_buffer_uptodate(bh);
3180                 btrfs_dev_stat_inc_and_print(device, BTRFS_DEV_STAT_WRITE_ERRS);
3181         }
3182         unlock_buffer(bh);
3183         put_bh(bh);
3184 }
3185
3186 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
3187 {
3188         struct buffer_head *bh;
3189         struct buffer_head *latest = NULL;
3190         struct btrfs_super_block *super;
3191         int i;
3192         u64 transid = 0;
3193         u64 bytenr;
3194
3195         /* we would like to check all the supers, but that would make
3196          * a btrfs mount succeed after a mkfs from a different FS.
3197          * So, we need to add a special mount option to scan for
3198          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
3199          */
3200         for (i = 0; i < 1; i++) {
3201                 bytenr = btrfs_sb_offset(i);
3202                 if (bytenr + BTRFS_SUPER_INFO_SIZE >=
3203                                         i_size_read(bdev->bd_inode))
3204                         break;
3205                 bh = __bread(bdev, bytenr / 4096,
3206                                         BTRFS_SUPER_INFO_SIZE);
3207                 if (!bh)
3208                         continue;
3209
3210                 super = (struct btrfs_super_block *)bh->b_data;
3211                 if (btrfs_super_bytenr(super) != bytenr ||
3212                     btrfs_super_magic(super) != BTRFS_MAGIC) {
3213                         brelse(bh);
3214                         continue;
3215                 }
3216
3217                 if (!latest || btrfs_super_generation(super) > transid) {
3218                         brelse(latest);
3219                         latest = bh;
3220                         transid = btrfs_super_generation(super);
3221                 } else {
3222                         brelse(bh);
3223                 }
3224         }
3225         return latest;
3226 }
3227
3228 /*
3229  * this should be called twice, once with wait == 0 and
3230  * once with wait == 1.  When wait == 0 is done, all the buffer heads
3231  * we write are pinned.
3232  *
3233  * They are released when wait == 1 is done.
3234  * max_mirrors must be the same for both runs, and it indicates how
3235  * many supers on this one device should be written.
3236  *
3237  * max_mirrors == 0 means to write them all.
3238  */
3239 static int write_dev_supers(struct btrfs_device *device,
3240                             struct btrfs_super_block *sb,
3241                             int do_barriers, int wait, int max_mirrors)
3242 {
3243         struct buffer_head *bh;
3244         int i;
3245         int ret;
3246         int errors = 0;
3247         u32 crc;
3248         u64 bytenr;
3249
3250         if (max_mirrors == 0)
3251                 max_mirrors = BTRFS_SUPER_MIRROR_MAX;
3252
3253         for (i = 0; i < max_mirrors; i++) {
3254                 bytenr = btrfs_sb_offset(i);
3255                 if (bytenr + BTRFS_SUPER_INFO_SIZE >=
3256                     device->commit_total_bytes)
3257                         break;
3258
3259                 if (wait) {
3260                         bh = __find_get_block(device->bdev, bytenr / 4096,
3261                                               BTRFS_SUPER_INFO_SIZE);
3262                         if (!bh) {
3263                                 errors++;
3264                                 continue;
3265                         }
3266                         wait_on_buffer(bh);
3267                         if (!buffer_uptodate(bh))
3268                                 errors++;
3269
3270                         /* drop our reference */
3271                         brelse(bh);
3272
3273                         /* drop the reference from the wait == 0 run */
3274                         brelse(bh);
3275                         continue;
3276                 } else {
3277                         btrfs_set_super_bytenr(sb, bytenr);
3278
3279                         crc = ~(u32)0;
3280                         crc = btrfs_csum_data((char *)sb +
3281                                               BTRFS_CSUM_SIZE, crc,
3282                                               BTRFS_SUPER_INFO_SIZE -
3283                                               BTRFS_CSUM_SIZE);
3284                         btrfs_csum_final(crc, sb->csum);
3285
3286                         /*
3287                          * one reference for us, and we leave it for the
3288                          * caller
3289                          */
3290                         bh = __getblk(device->bdev, bytenr / 4096,
3291                                       BTRFS_SUPER_INFO_SIZE);
3292                         if (!bh) {
3293                                 printk(KERN_ERR "BTRFS: couldn't get super "
3294                                        "buffer head for bytenr %Lu\n", bytenr);
3295                                 errors++;
3296                                 continue;
3297                         }
3298
3299                         memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
3300
3301                         /* one reference for submit_bh */
3302                         get_bh(bh);
3303
3304                         set_buffer_uptodate(bh);
3305                         lock_buffer(bh);
3306                         bh->b_end_io = btrfs_end_buffer_write_sync;
3307                         bh->b_private = device;
3308                 }
3309
3310                 /*
3311                  * we fua the first super.  The others we allow
3312                  * to go down lazy.
3313                  */
3314                 if (i == 0)
3315                         ret = btrfsic_submit_bh(WRITE_FUA, bh);
3316                 else
3317                         ret = btrfsic_submit_bh(WRITE_SYNC, bh);
3318                 if (ret)
3319                         errors++;
3320         }
3321         return errors < i ? 0 : -1;
3322 }
3323
3324 /*
3325  * endio for the write_dev_flush, this will wake anyone waiting
3326  * for the barrier when it is done
3327  */
3328 static void btrfs_end_empty_barrier(struct bio *bio, int err)
3329 {
3330         if (err)
3331                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
3332         if (bio->bi_private)
3333                 complete(bio->bi_private);
3334         bio_put(bio);
3335 }
3336
3337 /*
3338  * trigger flushes for one the devices.  If you pass wait == 0, the flushes are
3339  * sent down.  With wait == 1, it waits for the previous flush.
3340  *
3341  * any device where the flush fails with eopnotsupp are flagged as not-barrier
3342  * capable
3343  */
3344 static int write_dev_flush(struct btrfs_device *device, int wait)
3345 {
3346         struct bio *bio;
3347         int ret = 0;
3348
3349         if (device->nobarriers)
3350                 return 0;
3351
3352         if (wait) {
3353                 bio = device->flush_bio;
3354                 if (!bio)
3355                         return 0;
3356
3357                 wait_for_completion(&device->flush_wait);
3358
3359                 if (!bio_flagged(bio, BIO_UPTODATE)) {
3360                         ret = -EIO;
3361                         btrfs_dev_stat_inc_and_print(device,
3362                                 BTRFS_DEV_STAT_FLUSH_ERRS);
3363                 }
3364
3365                 /* drop the reference from the wait == 0 run */
3366                 bio_put(bio);
3367                 device->flush_bio = NULL;
3368
3369                 return ret;
3370         }
3371
3372         /*
3373          * one reference for us, and we leave it for the
3374          * caller
3375          */
3376         device->flush_bio = NULL;
3377         bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
3378         if (!bio)
3379                 return -ENOMEM;
3380
3381         bio->bi_end_io = btrfs_end_empty_barrier;
3382         bio->bi_bdev = device->bdev;
3383         init_completion(&device->flush_wait);
3384         bio->bi_private = &device->flush_wait;
3385         device->flush_bio = bio;
3386
3387         bio_get(bio);
3388         btrfsic_submit_bio(WRITE_FLUSH, bio);
3389
3390         return 0;
3391 }
3392
3393 /*
3394  * send an empty flush down to each device in parallel,
3395  * then wait for them
3396  */
3397 static int barrier_all_devices(struct btrfs_fs_info *info)
3398 {
3399         struct list_head *head;
3400         struct btrfs_device *dev;
3401         int errors_send = 0;
3402         int errors_wait = 0;
3403         int ret;
3404
3405         /* send down all the barriers */
3406         head = &info->fs_devices->devices;
3407         list_for_each_entry_rcu(dev, head, dev_list) {
3408                 if (dev->missing)
3409                         continue;
3410                 if (!dev->bdev) {
3411                         errors_send++;
3412                         continue;
3413                 }
3414                 if (!dev->in_fs_metadata || !dev->writeable)
3415                         continue;
3416
3417                 ret = write_dev_flush(dev, 0);
3418                 if (ret)
3419                         errors_send++;
3420         }
3421
3422         /* wait for all the barriers */
3423         list_for_each_entry_rcu(dev, head, dev_list) {
3424                 if (dev->missing)
3425                         continue;
3426                 if (!dev->bdev) {
3427                         errors_wait++;
3428                         continue;
3429                 }
3430                 if (!dev->in_fs_metadata || !dev->writeable)
3431                         continue;
3432
3433                 ret = write_dev_flush(dev, 1);
3434                 if (ret)
3435                         errors_wait++;
3436         }