fs/btrfs/disk-io.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/fs.h>
  20 #include <linux/blkdev.h>
  21 #include <linux/scatterlist.h>
  22 #include <linux/swap.h>
  23 #include <linux/radix-tree.h>
  24 #include <linux/writeback.h>
  25 #include <linux/buffer_head.h>
  26 #include <linux/workqueue.h>
  27 #include <linux/kthread.h>
  28 #include <linux/freezer.h>
  29 #include <linux/crc32c.h>
  30 #include <linux/slab.h>
  31 #include <linux/migrate.h>
  32 #include <asm/unaligned.h>
  33 #include "compat.h"
  34 #include "ctree.h"
  35 #include "disk-io.h"
  36 #include "transaction.h"
  37 #include "btrfs_inode.h"
  38 #include "volumes.h"
  39 #include "print-tree.h"
  40 #include "async-thread.h"
  41 #include "locking.h"
  42 #include "tree-log.h"
  43 #include "free-space-cache.h"
  44
  45 static struct extent_io_ops btree_extent_io_ops;
  46 static void end_workqueue_fn(struct btrfs_work *work);
  47 static void free_fs_root(struct btrfs_root *root);
  48 static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
  49                                     int read_only);
  50 static int btrfs_destroy_ordered_operations(struct btrfs_root *root);
  51 static int btrfs_destroy_ordered_extents(struct btrfs_root *root);
  52 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
  53                                       struct btrfs_root *root);
  54 static int btrfs_destroy_pending_snapshots(struct btrfs_transaction *t);
  55 static int btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
  56 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
  57                                         struct extent_io_tree *dirty_pages,
  58                                         int mark);
  59 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
  60                                        struct extent_io_tree *pinned_extents);
  61 static int btrfs_cleanup_transaction(struct btrfs_root *root);
  62
  63 /*
  64  * end_io_wq structs are used to do processing in task context when an IO is
  65  * complete.  This is used during reads to verify checksums, and it is used
  66  * by writes to insert metadata for new file extents after IO is complete.
  67  */
  68 struct end_io_wq {
  69         struct bio *bio;
  70         bio_end_io_t *end_io;
  71         void *private;
  72         struct btrfs_fs_info *info;
  73         int error;
  74         int metadata;
  75         struct list_head list;
  76         struct btrfs_work work;
  77 };
  78
  79 /*
  80  * async submit bios are used to offload expensive checksumming
  81  * onto the worker threads.  They checksum file and metadata bios
  82  * just before they are sent down the IO stack.
  83  */
  84 struct async_submit_bio {
  85         struct inode *inode;
  86         struct bio *bio;
  87         struct list_head list;
  88         extent_submit_bio_hook_t *submit_bio_start;
  89         extent_submit_bio_hook_t *submit_bio_done;
  90         int rw;
  91         int mirror_num;
  92         unsigned long bio_flags;
  93         /*
  94          * bio_offset is optional, can be used if the pages in the bio
  95          * can't tell us where in the file the bio should go
  96          */
  97         u64 bio_offset;
  98         struct btrfs_work work;
  99 };
 100
 101 /* These are used to set the lockdep class on the extent buffer locks.
 102  * The class is set by the readpage_end_io_hook after the buffer has
 103  * passed csum validation but before the pages are unlocked.
 104  *
 105  * The lockdep class is also set by btrfs_init_new_buffer on freshly
 106  * allocated blocks.
 107  *
 108  * The class is based on the level in the tree block, which allows lockdep
 109  * to know that lower nodes nest inside the locks of higher nodes.
 110  *
 111  * We also add a check to make sure the highest level of the tree is
 112  * the same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this
 113  * code needs update as well.
 114  */
 115 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 116 # if BTRFS_MAX_LEVEL != 8
 117 #  error
 118 # endif
 119 static struct lock_class_key btrfs_eb_class[BTRFS_MAX_LEVEL + 1];
 120 static const char *btrfs_eb_name[BTRFS_MAX_LEVEL + 1] = {
 121         /* leaf */
 122         "btrfs-extent-00",
 123         "btrfs-extent-01",
 124         "btrfs-extent-02",
 125         "btrfs-extent-03",
 126         "btrfs-extent-04",
 127         "btrfs-extent-05",
 128         "btrfs-extent-06",
 129         "btrfs-extent-07",
 130         /* highest possible level */
 131         "btrfs-extent-08",
 132 };
 133 #endif
 134
 135 /*
 136  * extents on the btree inode are pretty simple, there's one extent
 137  * that covers the entire device
 138  */
 139 static struct extent_map *btree_get_extent(struct inode *inode,
 140                 struct page *page, size_t page_offset, u64 start, u64 len,
 141                 int create)
 142 {
 143         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 144         struct extent_map *em;
 145         int ret;
 146
 147         read_lock(&em_tree->lock);
 148         em = lookup_extent_mapping(em_tree, start, len);
 149         if (em) {
 150                 em->bdev =
 151                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 152                 read_unlock(&em_tree->lock);
 153                 goto out;
 154         }
 155         read_unlock(&em_tree->lock);
 156
 157         em = alloc_extent_map(GFP_NOFS);
 158         if (!em) {
 159                 em = ERR_PTR(-ENOMEM);
 160                 goto out;
 161         }
 162         em->start = 0;
 163         em->len = (u64)-1;
 164         em->block_len = (u64)-1;
 165         em->block_start = 0;
 166         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 167
 168         write_lock(&em_tree->lock);
 169         ret = add_extent_mapping(em_tree, em);
 170         if (ret == -EEXIST) {
 171                 u64 failed_start = em->start;
 172                 u64 failed_len = em->len;
 173
 174                 free_extent_map(em);
 175                 em = lookup_extent_mapping(em_tree, start, len);
 176                 if (em) {
 177                         ret = 0;
 178                 } else {
 179                         em = lookup_extent_mapping(em_tree, failed_start,
 180                                                    failed_len);
 181                         ret = -EIO;
 182                 }
 183         } else if (ret) {
 184                 free_extent_map(em);
 185                 em = NULL;
 186         }
 187         write_unlock(&em_tree->lock);
 188
 189         if (ret)
 190                 em = ERR_PTR(ret);
 191 out:
 192         return em;
 193 }
 194
 195 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
 196 {
 197         return crc32c(seed, data, len);
 198 }
 199
 200 void btrfs_csum_final(u32 crc, char *result)
 201 {
 202         put_unaligned_le32(~crc, result);
 203 }
 204
 205 /*
 206  * compute the csum for a btree block, and either verify it or write it
 207  * into the csum field of the block.
 208  */
 209 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 210                            int verify)
 211 {
 212         u16 csum_size =
 213                 btrfs_super_csum_size(&root->fs_info->super_copy);
 214         char *result = NULL;
 215         unsigned long len;
 216         unsigned long cur_len;
 217         unsigned long offset = BTRFS_CSUM_SIZE;
 218         char *map_token = NULL;
 219         char *kaddr;
 220         unsigned long map_start;
 221         unsigned long map_len;
 222         int err;
 223         u32 crc = ~(u32)0;
 224         unsigned long inline_result;
 225
 226         len = buf->len - offset;
 227         while (len > 0) {
 228                 err = map_private_extent_buffer(buf, offset, 32,
 229                                         &map_token, &kaddr,
 230                                         &map_start, &map_len, KM_USER0);
 231                 if (err)
 232                         return 1;
 233                 cur_len = min(len, map_len - (offset - map_start));
 234                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
 235                                       crc, cur_len);
 236                 len -= cur_len;
 237                 offset += cur_len;
 238                 unmap_extent_buffer(buf, map_token, KM_USER0);
 239         }
 240         if (csum_size > sizeof(inline_result)) {
 241                 result = kzalloc(csum_size * sizeof(char), GFP_NOFS);
 242                 if (!result)
 243                         return 1;
 244         } else {
 245                 result = (char *)&inline_result;
 246         }
 247
 248         btrfs_csum_final(crc, result);
 249
 250         if (verify) {
 251                 if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
 252                         u32 val;
 253                         u32 found = 0;
 254                         memcpy(&found, result, csum_size);
 255
 256                         read_extent_buffer(buf, &val, 0, csum_size);
 257                         if (printk_ratelimit()) {
 258                                 printk(KERN_INFO "btrfs: %s checksum verify "
 259                                        "failed on %llu wanted %X found %X "
 260                                        "level %d\n",
 261                                        root->fs_info->sb->s_id,
 262                                        (unsigned long long)buf->start, val, found,
 263                                        btrfs_header_level(buf));
 264                         }
 265                         if (result != (char *)&inline_result)
 266                                 kfree(result);
 267                         return 1;
 268                 }
 269         } else {
 270                 write_extent_buffer(buf, result, 0, csum_size);
 271         }
 272         if (result != (char *)&inline_result)
 273                 kfree(result);
 274         return 0;
 275 }
 276
 277 /*
 278  * we can't consider a given block up to date unless the transid of the
 279  * block matches the transid in the parent node's pointer.  This is how we
 280  * detect blocks that either didn't get written at all or got written
 281  * in the wrong place.
 282  */
 283 static int verify_parent_transid(struct extent_io_tree *io_tree,
 284                                  struct extent_buffer *eb, u64 parent_transid)
 285 {
 286         struct extent_state *cached_state = NULL;
 287         int ret;
 288
 289         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
 290                 return 0;
 291
 292         lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
 293                          0, &cached_state, GFP_NOFS);
 294         if (extent_buffer_uptodate(io_tree, eb, cached_state) &&
 295             btrfs_header_generation(eb) == parent_transid) {
 296                 ret = 0;
 297                 goto out;
 298         }
 299         if (printk_ratelimit()) {
 300                 printk("parent transid verify failed on %llu wanted %llu "
 301                        "found %llu\n",
 302                        (unsigned long long)eb->start,
 303                        (unsigned long long)parent_transid,
 304                        (unsigned long long)btrfs_header_generation(eb));
 305         }
 306         ret = 1;
 307         clear_extent_buffer_uptodate(io_tree, eb, &cached_state);
 308 out:
 309         unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
 310                              &cached_state, GFP_NOFS);
 311         return ret;
 312 }
 313
 314 /*
 315  * helper to read a given tree block, doing retries as required when
 316  * the checksums don't match and we have alternate mirrors to try.
 317  */
 318 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
 319                                           struct extent_buffer *eb,
 320                                           u64 start, u64 parent_transid)
 321 {
 322         struct extent_io_tree *io_tree;
 323         int ret;
 324         int num_copies = 0;
 325         int mirror_num = 0;
 326
 327         clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
 328         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
 329         while (1) {
 330                 ret = read_extent_buffer_pages(io_tree, eb, start, 1,
 331                                                btree_get_extent, mirror_num);
 332                 if (!ret &&
 333                     !verify_parent_transid(io_tree, eb, parent_transid))
 334                         return ret;
 335
 336                 /*
 337                  * This buffer's crc is fine, but its contents are corrupted, so
 338                  * there is no reason to read the other copies, they won't be
 339                  * any less wrong.
 340                  */
 341                 if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags))
 342                         return ret;
 343
 344                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
 345                                               eb->start, eb->len);
 346                 if (num_copies == 1)
 347                         return ret;
 348
 349                 mirror_num++;
 350                 if (mirror_num > num_copies)
 351                         return ret;
 352         }
 353         return -EIO;
 354 }
 355
 356 /*
 357  * checksum a dirty tree block before IO.  This has extra checks to make sure
 358  * we only fill in the checksum field in the first page of a multi-page block
 359  */
 360
 361 static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 362 {
 363         struct extent_io_tree *tree;
 364         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
 365         u64 found_start;
 366         unsigned long len;
 367         struct extent_buffer *eb;
 368         int ret;
 369
 370         tree = &BTRFS_I(page->mapping->host)->io_tree;
 371
 372         if (page->private == EXTENT_PAGE_PRIVATE) {
 373                 WARN_ON(1);
 374                 goto out;
 375         }
 376         if (!page->private) {
 377                 WARN_ON(1);
 378                 goto out;
 379         }
 380         len = page->private >> 2;
 381         WARN_ON(len == 0);
 382
 383         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 384         if (eb == NULL) {
 385                 WARN_ON(1);
 386                 goto out;
 387         }
 388         ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
 389                                              btrfs_header_generation(eb));
 390         BUG_ON(ret);
 391         WARN_ON(!btrfs_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN));
 392
 393         found_start = btrfs_header_bytenr(eb);
 394         if (found_start != start) {
 395                 WARN_ON(1);
 396                 goto err;
 397         }
 398         if (eb->first_page != page) {
 399                 WARN_ON(1);
 400                 goto err;
 401         }
 402         if (!PageUptodate(page)) {
 403                 WARN_ON(1);
 404                 goto err;
 405         }
 406         csum_tree_block(root, eb, 0);
 407 err:
 408         free_extent_buffer(eb);
 409 out:
 410         return 0;
 411 }
 412
 413 static int check_tree_block_fsid(struct btrfs_root *root,
 414                                  struct extent_buffer *eb)
 415 {
 416         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
 417         u8 fsid[BTRFS_UUID_SIZE];
 418         int ret = 1;
 419
 420         read_extent_buffer(eb, fsid, (unsigned long)btrfs_header_fsid(eb),
 421                            BTRFS_FSID_SIZE);
 422         while (fs_devices) {
 423                 if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
 424                         ret = 0;
 425                         break;
 426                 }
 427                 fs_devices = fs_devices->seed;
 428         }
 429         return ret;
 430 }
 431
 432 #define CORRUPT(reason, eb, root, slot)                         \
 433         printk(KERN_CRIT "btrfs: corrupt leaf, %s: block=%llu," \
 434                "root=%llu, slot=%d\n", reason,                  \
 435                (unsigned long long)btrfs_header_bytenr(eb),     \
 436                (unsigned long long)root->objectid, slot)
 437
 438 static noinline int check_leaf(struct btrfs_root *root,
 439                                struct extent_buffer *leaf)
 440 {
 441         struct btrfs_key key;
 442         struct btrfs_key leaf_key;
 443         u32 nritems = btrfs_header_nritems(leaf);
 444         int slot;
 445
 446         if (nritems == 0)
 447                 return 0;
 448
 449         /* Check the 0 item */
 450         if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
 451             BTRFS_LEAF_DATA_SIZE(root)) {
 452                 CORRUPT("invalid item offset size pair", leaf, root, 0);
 453                 return -EIO;
 454         }
 455
 456         /*
 457          * Check to make sure each items keys are in the correct order and their
 458          * offsets make sense.  We only have to loop through nritems-1 because
 459          * we check the current slot against the next slot, which verifies the
 460          * next slot's offset+size makes sense and that the current's slot
 461          * offset is correct.
 462          */
 463         for (slot = 0; slot < nritems - 1; slot++) {
 464                 btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
 465                 btrfs_item_key_to_cpu(leaf, &key, slot + 1);
 466
 467                 /* Make sure the keys are in the right order */
 468                 if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
 469                         CORRUPT("bad key order", leaf, root, slot);
 470                         return -EIO;
 471                 }
 472
 473                 /*
 474                  * Make sure the offset and ends are right, remember that the
 475                  * item data starts at the end of the leaf and grows towards the
 476                  * front.
 477                  */
 478                 if (btrfs_item_offset_nr(leaf, slot) !=
 479                         btrfs_item_end_nr(leaf, slot + 1)) {
 480                         CORRUPT("slot offset bad", leaf, root, slot);
 481                         return -EIO;
 482                 }
 483
 484                 /*
 485                  * Check to make sure that we don't point outside of the leaf,
 486                  * just incase all the items are consistent to eachother, but
 487                  * all point outside of the leaf.
 488                  */
 489                 if (btrfs_item_end_nr(leaf, slot) >
 490                     BTRFS_LEAF_DATA_SIZE(root)) {
 491                         CORRUPT("slot end outside of leaf", leaf, root, slot);
 492                         return -EIO;
 493                 }
 494         }
 495
 496         return 0;
 497 }
 498
 499 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 500 void btrfs_set_buffer_lockdep_class(struct extent_buffer *eb, int level)
 501 {
 502         lockdep_set_class_and_name(&eb->lock,
 503                            &btrfs_eb_class[level],
 504                            btrfs_eb_name[level]);
 505 }
 506 #endif
 507
 508 static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 509                                struct extent_state *state)
 510 {
 511         struct extent_io_tree *tree;
 512         u64 found_start;
 513         int found_level;
 514         unsigned long len;
 515         struct extent_buffer *eb;
 516         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 517         int ret = 0;
 518
 519         tree = &BTRFS_I(page->mapping->host)->io_tree;
 520         if (page->private == EXTENT_PAGE_PRIVATE)
 521                 goto out;
 522         if (!page->private)
 523                 goto out;
 524
 525         len = page->private >> 2;
 526         WARN_ON(len == 0);
 527
 528         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 529         if (eb == NULL) {
 530                 ret = -EIO;
 531                 goto out;
 532         }
 533
 534         found_start = btrfs_header_bytenr(eb);
 535         if (found_start != start) {
 536                 if (printk_ratelimit()) {
 537                         printk(KERN_INFO "btrfs bad tree block start "
 538                                "%llu %llu\n",
 539                                (unsigned long long)found_start,
 540                                (unsigned long long)eb->start);
 541                 }
 542                 ret = -EIO;
 543                 goto err;
 544         }
 545         if (eb->first_page != page) {
 546                 printk(KERN_INFO "btrfs bad first page %lu %lu\n",
 547                        eb->first_page->index, page->index);
 548                 WARN_ON(1);
 549                 ret = -EIO;
 550                 goto err;
 551         }
 552         if (check_tree_block_fsid(root, eb)) {
 553                 if (printk_ratelimit()) {
 554                         printk(KERN_INFO "btrfs bad fsid on block %llu\n",
 555                                (unsigned long long)eb->start);
 556                 }
 557                 ret = -EIO;
 558                 goto err;
 559         }
 560         found_level = btrfs_header_level(eb);
 561
 562         btrfs_set_buffer_lockdep_class(eb, found_level);
 563
 564         ret = csum_tree_block(root, eb, 1);
 565         if (ret) {
 566                 ret = -EIO;
 567                 goto err;
 568         }
 569
 570         /*
 571          * If this is a leaf block and it is corrupt, set the corrupt bit so
 572          * that we don't try and read the other copies of this block, just
 573          * return -EIO.
 574          */
 575         if (found_level == 0 && check_leaf(root, eb)) {
 576                 set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
 577                 ret = -EIO;
 578         }
 579
 580         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
 581         end = eb->start + end - 1;
 582 err:
 583         free_extent_buffer(eb);
 584 out:
 585         return ret;
 586 }
 587
 588 static void end_workqueue_bio(struct bio *bio, int err)
 589 {
 590         struct end_io_wq *end_io_wq = bio->bi_private;
 591         struct btrfs_fs_info *fs_info;
 592
 593         fs_info = end_io_wq->info;
 594         end_io_wq->error = err;
 595         end_io_wq->work.func = end_workqueue_fn;
 596         end_io_wq->work.flags = 0;
 597
 598         if (bio->bi_rw & REQ_WRITE) {
 599                 if (end_io_wq->metadata == 1)
 600                         btrfs_queue_worker(&fs_info->endio_meta_write_workers,
 601                                            &end_io_wq->work);
 602                 else if (end_io_wq->metadata == 2)
 603                         btrfs_queue_worker(&fs_info->endio_freespace_worker,
 604                                            &end_io_wq->work);
 605                 else
 606                         btrfs_queue_worker(&fs_info->endio_write_workers,
 607                                            &end_io_wq->work);
 608         } else {
 609                 if (end_io_wq->metadata)
 610                         btrfs_queue_worker(&fs_info->endio_meta_workers,
 611                                            &end_io_wq->work);
 612                 else
 613                         btrfs_queue_worker(&fs_info->endio_workers,
 614                                            &end_io_wq->work);
 615         }
 616 }
 617
 618 /*
 619  * For the metadata arg you want
 620  *
 621  * 0 - if data
 622  * 1 - if normal metadta
 623  * 2 - if writing to the free space cache area
 624  */
 625 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 626                         int metadata)
 627 {
 628         struct end_io_wq *end_io_wq;
 629         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
 630         if (!end_io_wq)
 631                 return -ENOMEM;
 632
 633         end_io_wq->private = bio->bi_private;
 634         end_io_wq->end_io = bio->bi_end_io;
 635         end_io_wq->info = info;
 636         end_io_wq->error = 0;
 637         end_io_wq->bio = bio;
 638         end_io_wq->metadata = metadata;
 639
 640         bio->bi_private = end_io_wq;
 641         bio->bi_end_io = end_workqueue_bio;
 642         return 0;
 643 }
 644
 645 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
 646 {
 647         unsigned long limit = min_t(unsigned long,
 648                                     info->workers.max_workers,
 649                                     info->fs_devices->open_devices);
 650         return 256 * limit;
 651 }
 652
 653 int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
 654 {
 655         return atomic_read(&info->nr_async_bios) >
 656                 btrfs_async_submit_limit(info);
 657 }
 658
 659 static void run_one_async_start(struct btrfs_work *work)
 660 {
 661         struct async_submit_bio *async;
 662
 663         async = container_of(work, struct  async_submit_bio, work);
 664         async->submit_bio_start(async->inode, async->rw, async->bio,
 665                                async->mirror_num, async->bio_flags,
 666                                async->bio_offset);
 667 }
 668
 669 static void run_one_async_done(struct btrfs_work *work)
 670 {
 671         struct btrfs_fs_info *fs_info;
 672         struct async_submit_bio *async;
 673         int limit;
 674
 675         async = container_of(work, struct  async_submit_bio, work);
 676         fs_info = BTRFS_I(async->inode)->root->fs_info;
 677
 678         limit = btrfs_async_submit_limit(fs_info);
 679         limit = limit * 2 / 3;
 680
 681         atomic_dec(&fs_info->nr_async_submits);
 682
 683         if (atomic_read(&fs_info->nr_async_submits) < limit &&
 684             waitqueue_active(&fs_info->async_submit_wait))
 685                 wake_up(&fs_info->async_submit_wait);
 686
 687         async->submit_bio_done(async->inode, async->rw, async->bio,
 688                                async->mirror_num, async->bio_flags,
 689                                async->bio_offset);
 690 }
 691
 692 static void run_one_async_free(struct btrfs_work *work)
 693 {
 694         struct async_submit_bio *async;
 695
 696         async = container_of(work, struct  async_submit_bio, work);
 697         kfree(async);
 698 }
 699
 700 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 701                         int rw, struct bio *bio, int mirror_num,
 702                         unsigned long bio_flags,
 703                         u64 bio_offset,
 704                         extent_submit_bio_hook_t *submit_bio_start,
 705                         extent_submit_bio_hook_t *submit_bio_done)
 706 {
 707         struct async_submit_bio *async;
 708
 709         async = kmalloc(sizeof(*async), GFP_NOFS);
 710         if (!async)
 711                 return -ENOMEM;
 712
 713         async->inode = inode;
 714         async->rw = rw;
 715         async->bio = bio;
 716         async->mirror_num = mirror_num;
 717         async->submit_bio_start = submit_bio_start;
 718         async->submit_bio_done = submit_bio_done;
 719
 720         async->work.func = run_one_async_start;
 721         async->work.ordered_func = run_one_async_done;
 722         async->work.ordered_free = run_one_async_free;
 723
 724         async->work.flags = 0;
 725         async->bio_flags = bio_flags;
 726         async->bio_offset = bio_offset;
 727
 728         atomic_inc(&fs_info->nr_async_submits);
 729
 730         if (rw & REQ_SYNC)
 731                 btrfs_set_work_high_prio(&async->work);
 732
 733         btrfs_queue_worker(&fs_info->workers, &async->work);
 734
 735         while (atomic_read(&fs_info->async_submit_draining) &&
 736               atomic_read(&fs_info->nr_async_submits)) {
 737                 wait_event(fs_info->async_submit_wait,
 738                            (atomic_read(&fs_info->nr_async_submits) == 0));
 739         }
 740
 741         return 0;
 742 }
 743
 744 static int btree_csum_one_bio(struct bio *bio)
 745 {
 746         struct bio_vec *bvec = bio->bi_io_vec;
 747         int bio_index = 0;
 748         struct btrfs_root *root;
 749
 750         WARN_ON(bio->bi_vcnt <= 0);
 751         while (bio_index < bio->bi_vcnt) {
 752                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
 753                 csum_dirty_buffer(root, bvec->bv_page);
 754                 bio_index++;
 755                 bvec++;
 756         }
 757         return 0;
 758 }
 759
 760 static int __btree_submit_bio_start(struct inode *inode, int rw,
 761                                     struct bio *bio, int mirror_num,
 762                                     unsigned long bio_flags,
 763                                     u64 bio_offset)
 764 {
 765         /*
 766          * when we're called for a write, we're already in the async
 767          * submission context.  Just jump into btrfs_map_bio
 768          */
 769         btree_csum_one_bio(bio);
 770         return 0;
 771 }
 772
 773 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
 774                                  int mirror_num, unsigned long bio_flags,
 775                                  u64 bio_offset)
 776 {
 777         /*
 778          * when we're called for a write, we're already in the async
 779          * submission context.  Just jump into btrfs_map_bio
 780          */
 781         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
 782 }
 783
 784 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 785                                  int mirror_num, unsigned long bio_flags,
 786                                  u64 bio_offset)
 787 {
 788         int ret;
 789
 790         ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
 791                                           bio, 1);
 792         BUG_ON(ret);
 793
 794         if (!(rw & REQ_WRITE)) {
 795                 /*
 796                  * called for a read, do the setup so that checksum validation
 797                  * can happen in the async kernel threads
 798                  */
 799                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 800                                      mirror_num, 0);
 801         }
 802
 803         /*
 804          * kthread helpers are used to submit writes so that checksumming
 805          * can happen in parallel across all CPUs
 806          */
 807         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
 808                                    inode, rw, bio, mirror_num, 0,
 809                                    bio_offset,
 810                                    __btree_submit_bio_start,
 811                                    __btree_submit_bio_done);
 812 }
 813
 814 #ifdef CONFIG_MIGRATION
 815 static int btree_migratepage(struct address_space *mapping,
 816                         struct page *newpage, struct page *page)
 817 {
 818         /*
 819          * we can't safely write a btree page from here,
 820          * we haven't done the locking hook
 821          */
 822         if (PageDirty(page))
 823                 return -EAGAIN;
 824         /*
 825          * Buffers may be managed in a filesystem specific way.
 826          * We must have no buffers or drop them.
 827          */
 828         if (page_has_private(page) &&
 829             !try_to_release_page(page, GFP_KERNEL))
 830                 return -EAGAIN;
 831         return migrate_page(mapping, newpage, page);
 832 }
 833 #endif
 834
 835 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 836 {
 837         struct extent_io_tree *tree;
 838         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 839         struct extent_buffer *eb;
 840         int was_dirty;
 841
 842         tree = &BTRFS_I(page->mapping->host)->io_tree;
 843         if (!(current->flags & PF_MEMALLOC)) {
 844                 return extent_write_full_page(tree, page,
 845                                               btree_get_extent, wbc);
 846         }
 847
 848         redirty_page_for_writepage(wbc, page);
 849         eb = btrfs_find_tree_block(root, page_offset(page), PAGE_CACHE_SIZE);
 850         WARN_ON(!eb);
 851
 852         was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
 853         if (!was_dirty) {
 854                 spin_lock(&root->fs_info->delalloc_lock);
 855                 root->fs_info->dirty_metadata_bytes += PAGE_CACHE_SIZE;
 856                 spin_unlock(&root->fs_info->delalloc_lock);
 857         }
 858         free_extent_buffer(eb);
 859
 860         unlock_page(page);
 861         return 0;
 862 }
 863
 864 static int btree_writepages(struct address_space *mapping,
 865                             struct writeback_control *wbc)
 866 {
 867         struct extent_io_tree *tree;
 868         tree = &BTRFS_I(mapping->host)->io_tree;
 869         if (wbc->sync_mode == WB_SYNC_NONE) {
 870                 struct btrfs_root *root = BTRFS_I(mapping->host)->root;
 871                 u64 num_dirty;
 872                 unsigned long thresh = 32 * 1024 * 1024;
 873
 874                 if (wbc->for_kupdate)
 875                         return 0;
 876
 877                 /* this is a bit racy, but that's ok */
 878                 num_dirty = root->fs_info->dirty_metadata_bytes;
 879                 if (num_dirty < thresh)
 880                         return 0;
 881         }
 882         return extent_writepages(tree, mapping, btree_get_extent, wbc);
 883 }
 884
 885 static int btree_readpage(struct file *file, struct page *page)
 886 {
 887         struct extent_io_tree *tree;
 888         tree = &BTRFS_I(page->mapping->host)->io_tree;
 889         return extent_read_full_page(tree, page, btree_get_extent);
 890 }
 891
 892 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 893 {
 894         struct extent_io_tree *tree;
 895         struct extent_map_tree *map;
 896         int ret;
 897
 898         if (PageWriteback(page) || PageDirty(page))
 899                 return 0;
 900
 901         tree = &BTRFS_I(page->mapping->host)->io_tree;
 902         map = &BTRFS_I(page->mapping->host)->extent_tree;
 903
 904         ret = try_release_extent_state(map, tree, page, gfp_flags);
 905         if (!ret)
 906                 return 0;
 907
 908         ret = try_release_extent_buffer(tree, page);
 909         if (ret == 1) {
 910                 ClearPagePrivate(page);
 911                 set_page_private(page, 0);
 912                 page_cache_release(page);
 913         }
 914
 915         return ret;
 916 }
 917
 918 static void btree_invalidatepage(struct page *page, unsigned long offset)
 919 {
 920         struct extent_io_tree *tree;
 921         tree = &BTRFS_I(page->mapping->host)->io_tree;
 922         extent_invalidatepage(tree, page, offset);
 923         btree_releasepage(page, GFP_NOFS);
 924         if (PagePrivate(page)) {
 925                 printk(KERN_WARNING "btrfs warning page private not zero "
 926                        "on page %llu\n", (unsigned long long)page_offset(page));
 927                 ClearPagePrivate(page);
 928                 set_page_private(page, 0);
 929                 page_cache_release(page);
 930         }
 931 }
 932
 933 static const struct address_space_operations btree_aops = {
 934         .readpage       = btree_readpage,
 935         .writepage      = btree_writepage,
 936         .writepages     = btree_writepages,
 937         .releasepage    = btree_releasepage,
 938         .invalidatepage = btree_invalidatepage,
 939         .sync_page      = block_sync_page,
 940 #ifdef CONFIG_MIGRATION
 941         .migratepage    = btree_migratepage,
 942 #endif
 943 };
 944
 945 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 946                          u64 parent_transid)
 947 {
 948         struct extent_buffer *buf = NULL;
 949         struct inode *btree_inode = root->fs_info->btree_inode;
 950         int ret = 0;
 951
 952         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 953         if (!buf)
 954                 return 0;
 955         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
 956                                  buf, 0, 0, btree_get_extent, 0);
 957         free_extent_buffer(buf);
 958         return ret;
 959 }
 960
 961 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
 962                                             u64 bytenr, u32 blocksize)
 963 {
 964         struct inode *btree_inode = root->fs_info->btree_inode;
 965         struct extent_buffer *eb;
 966         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 967                                 bytenr, blocksize, GFP_NOFS);
 968         return eb;
 969 }
 970
 971 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 972                                                  u64 bytenr, u32 blocksize)
 973 {
 974         struct inode *btree_inode = root->fs_info->btree_inode;
 975         struct extent_buffer *eb;
 976
 977         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 978                                  bytenr, blocksize, NULL, GFP_NOFS);
 979         return eb;
 980 }
 981
 982
 983 int btrfs_write_tree_block(struct extent_buffer *buf)
 984 {
 985         return filemap_fdatawrite_range(buf->first_page->mapping, buf->start,
 986                                         buf->start + buf->len - 1);
 987 }
 988
 989 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
 990 {
 991         return filemap_fdatawait_range(buf->first_page->mapping,
 992                                        buf->start, buf->start + buf->len - 1);
 993 }
 994
 995 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 996                                       u32 blocksize, u64 parent_transid)
 997 {
 998         struct extent_buffer *buf = NULL;
 999         int ret;
1000
1001         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1002         if (!buf)
1003                 return NULL;
1004
1005         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1006
1007         if (ret == 0)
1008                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
1009         return buf;
1010
1011 }
1012
1013 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1014                      struct extent_buffer *buf)
1015 {
1016         struct inode *btree_inode = root->fs_info->btree_inode;
1017         if (btrfs_header_generation(buf) ==
1018             root->fs_info->running_transaction->transid) {
1019                 btrfs_assert_tree_locked(buf);
1020
1021                 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
1022                         spin_lock(&root->fs_info->delalloc_lock);
1023                         if (root->fs_info->dirty_metadata_bytes >= buf->len)
1024                                 root->fs_info->dirty_metadata_bytes -= buf->len;
1025                         else
1026                                 WARN_ON(1);
1027                         spin_unlock(&root->fs_info->delalloc_lock);
1028                 }
1029
1030                 /* ugh, clear_extent_buffer_dirty needs to lock the page */
1031                 btrfs_set_lock_blocking(buf);
1032                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
1033                                           buf);
1034         }
1035         return 0;
1036 }
1037
1038 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
1039                         u32 stripesize, struct btrfs_root *root,
1040                         struct btrfs_fs_info *fs_info,
1041                         u64 objectid)
1042 {
1043         root->node = NULL;
1044         root->commit_root = NULL;
1045         root->sectorsize = sectorsize;
1046         root->nodesize = nodesize;
1047         root->leafsize = leafsize;
1048         root->stripesize = stripesize;
1049         root->ref_cows = 0;
1050         root->track_dirty = 0;
1051         root->in_radix = 0;
1052         root->orphan_item_inserted = 0;
1053         root->orphan_cleanup_state = 0;
1054
1055         root->fs_info = fs_info;
1056         root->objectid = objectid;
1057         root->last_trans = 0;
1058         root->highest_objectid = 0;
1059         root->name = NULL;
1060         root->in_sysfs = 0;
1061         root->inode_tree = RB_ROOT;
1062         root->block_rsv = NULL;
1063         root->orphan_block_rsv = NULL;
1064
1065         INIT_LIST_HEAD(&root->dirty_list);
1066         INIT_LIST_HEAD(&root->orphan_list);
1067         INIT_LIST_HEAD(&root->root_list);
1068         spin_lock_init(&root->node_lock);
1069         spin_lock_init(&root->orphan_lock);
1070         spin_lock_init(&root->inode_lock);
1071         spin_lock_init(&root->accounting_lock);
1072         mutex_init(&root->objectid_mutex);
1073         mutex_init(&root->log_mutex);
1074         init_waitqueue_head(&root->log_writer_wait);
1075         init_waitqueue_head(&root->log_commit_wait[0]);
1076         init_waitqueue_head(&root->log_commit_wait[1]);
1077         atomic_set(&root->log_commit[0], 0);
1078         atomic_set(&root->log_commit[1], 0);
1079         atomic_set(&root->log_writers, 0);
1080         root->log_batch = 0;
1081         root->log_transid = 0;
1082         root->last_log_commit = 0;
1083         extent_io_tree_init(&root->dirty_log_pages,
1084                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1085
1086         memset(&root->root_key, 0, sizeof(root->root_key));
1087         memset(&root->root_item, 0, sizeof(root->root_item));
1088         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
1089         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
1090         root->defrag_trans_start = fs_info->generation;
1091         init_completion(&root->kobj_unregister);
1092         root->defrag_running = 0;
1093         root->root_key.objectid = objectid;
1094         root->anon_super.s_root = NULL;
1095         root->anon_super.s_dev = 0;
1096         INIT_LIST_HEAD(&root->anon_super.s_list);
1097         INIT_LIST_HEAD(&root->anon_super.s_instances);
1098         init_rwsem(&root->anon_super.s_umount);
1099
1100         return 0;
1101 }
1102
1103 static int find_and_setup_root(struct btrfs_root *tree_root,
1104                                struct btrfs_fs_info *fs_info,
1105                                u64 objectid,
1106                                struct btrfs_root *root)
1107 {
1108         int ret;
1109         u32 blocksize;
1110         u64 generation;
1111
1112         __setup_root(tree_root->nodesize, tree_root->leafsize,
1113                      tree_root->sectorsize, tree_root->stripesize,
1114                      root, fs_info, objectid);
1115         ret = btrfs_find_last_root(tree_root, objectid,
1116                                    &root->root_item, &root->root_key);
1117         if (ret > 0)
1118                 return -ENOENT;
1119         BUG_ON(ret);
1120
1121         generation = btrfs_root_generation(&root->root_item);
1122         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1123         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1124                                      blocksize, generation);
1125         if (!root->node || !btrfs_buffer_uptodate(root->node, generation)) {
1126                 free_extent_buffer(root->node);
1127                 return -EIO;
1128         }
1129         root->commit_root = btrfs_root_node(root);
1130         return 0;
1131 }
1132
1133 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1134                                          struct btrfs_fs_info *fs_info)
1135 {
1136         struct btrfs_root *root;
1137         struct btrfs_root *tree_root = fs_info->tree_root;
1138         struct extent_buffer *leaf;
1139
1140         root = kzalloc(sizeof(*root), GFP_NOFS);
1141         if (!root)
1142                 return ERR_PTR(-ENOMEM);
1143
1144         __setup_root(tree_root->nodesize, tree_root->leafsize,
1145                      tree_root->sectorsize, tree_root->stripesize,
1146                      root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1147
1148         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1149         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1150         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1151         /*
1152          * log trees do not get reference counted because they go away
1153          * before a real commit is actually done.  They do store pointers
1154          * to file data extents, and those reference counts still get
1155          * updated (along with back refs to the log tree).
1156          */
1157         root->ref_cows = 0;
1158
1159         leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
1160                                       BTRFS_TREE_LOG_OBJECTID, NULL, 0, 0, 0);
1161         if (IS_ERR(leaf)) {
1162                 kfree(root);
1163                 return ERR_CAST(leaf);
1164         }
1165
1166         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1167         btrfs_set_header_bytenr(leaf, leaf->start);
1168         btrfs_set_header_generation(leaf, trans->transid);
1169         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1170         btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1171         root->node = leaf;
1172
1173         write_extent_buffer(root->node, root->fs_info->fsid,
1174                             (unsigned long)btrfs_header_fsid(root->node),
1175                             BTRFS_FSID_SIZE);
1176         btrfs_mark_buffer_dirty(root->node);
1177         btrfs_tree_unlock(root->node);
1178         return root;
1179 }
1180
1181 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1182                              struct btrfs_fs_info *fs_info)
1183 {
1184         struct btrfs_root *log_root;
1185
1186         log_root = alloc_log_tree(trans, fs_info);
1187         if (IS_ERR(log_root))
1188                 return PTR_ERR(log_root);
1189         WARN_ON(fs_info->log_root_tree);
1190         fs_info->log_root_tree = log_root;
1191         return 0;
1192 }
1193
1194 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1195                        struct btrfs_root *root)
1196 {
1197         struct btrfs_root *log_root;
1198         struct btrfs_inode_item *inode_item;
1199
1200         log_root = alloc_log_tree(trans, root->fs_info);
1201         if (IS_ERR(log_root))
1202                 return PTR_ERR(log_root);
1203
1204         log_root->last_trans = trans->transid;
1205         log_root->root_key.offset = root->root_key.objectid;
1206
1207         inode_item = &log_root->root_item.inode;
1208         inode_item->generation = cpu_to_le64(1);
1209         inode_item->size = cpu_to_le64(3);
1210         inode_item->nlink = cpu_to_le32(1);
1211         inode_item->nbytes = cpu_to_le64(root->leafsize);
1212         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
1213
1214         btrfs_set_root_node(&log_root->root_item, log_root->node);
1215
1216         WARN_ON(root->log_root);
1217         root->log_root = log_root;
1218         root->log_transid = 0;
1219         root->last_log_commit = 0;
1220         return 0;
1221 }
1222
1223 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
1224                                                struct btrfs_key *location)
1225 {
1226         struct btrfs_root *root;
1227         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1228         struct btrfs_path *path;
1229         struct extent_buffer *l;
1230         u64 generation;
1231         u32 blocksize;
1232         int ret = 0;
1233
1234         root = kzalloc(sizeof(*root), GFP_NOFS);
1235         if (!root)
1236                 return ERR_PTR(-ENOMEM);
1237         if (location->offset == (u64)-1) {
1238                 ret = find_and_setup_root(tree_root, fs_info,
1239                                           location->objectid, root);
1240                 if (ret) {
1241                         kfree(root);
1242                         return ERR_PTR(ret);
1243                 }
1244                 goto out;
1245         }
1246
1247         __setup_root(tree_root->nodesize, tree_root->leafsize,
1248                      tree_root->sectorsize, tree_root->stripesize,
1249                      root, fs_info, location->objectid);
1250
1251         path = btrfs_alloc_path();
1252         if (!path) {
1253                 kfree(root);
1254                 return ERR_PTR(-ENOMEM);
1255         }
1256         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
1257         if (ret == 0) {
1258                 l = path->nodes[0];
1259                 read_extent_buffer(l, &root->root_item,
1260                                 btrfs_item_ptr_offset(l, path->slots[0]),
1261                                 sizeof(root->root_item));
1262                 memcpy(&root->root_key, location, sizeof(*location));
1263         }
1264         btrfs_free_path(path);
1265         if (ret) {
1266                 kfree(root);
1267                 if (ret > 0)
1268                         ret = -ENOENT;
1269                 return ERR_PTR(ret);
1270         }
1271
1272         generation = btrfs_root_generation(&root->root_item);
1273         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1274         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1275                                      blocksize, generation);
1276         root->commit_root = btrfs_root_node(root);
1277         BUG_ON(!root->node);
1278 out:
1279         if (location->objectid != BTRFS_TREE_LOG_OBJECTID)
1280                 root->ref_cows = 1;
1281
1282         return root;
1283 }
1284
1285 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1286                                         u64 root_objectid)
1287 {
1288         struct btrfs_root *root;
1289
1290         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
1291                 return fs_info->tree_root;
1292         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
1293                 return fs_info->extent_root;
1294
1295         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1296                                  (unsigned long)root_objectid);
1297         return root;
1298 }
1299
1300 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
1301                                               struct btrfs_key *location)
1302 {
1303         struct btrfs_root *root;
1304         int ret;
1305
1306         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1307                 return fs_info->tree_root;
1308         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1309                 return fs_info->extent_root;
1310         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1311                 return fs_info->chunk_root;
1312         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1313                 return fs_info->dev_root;
1314         if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1315                 return fs_info->csum_root;
1316 again:
1317         spin_lock(&fs_info->fs_roots_radix_lock);
1318         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1319                                  (unsigned long)location->objectid);
1320         spin_unlock(&fs_info->fs_roots_radix_lock);
1321         if (root)
1322                 return root;
1323
1324         root = btrfs_read_fs_root_no_radix(fs_info->tree_root, location);
1325         if (IS_ERR(root))
1326                 return root;
1327
1328         set_anon_super(&root->anon_super, NULL);
1329
1330         if (btrfs_root_refs(&root->root_item) == 0) {
1331                 ret = -ENOENT;
1332                 goto fail;
1333         }
1334
1335         ret = btrfs_find_orphan_item(fs_info->tree_root, location->objectid);
1336         if (ret < 0)
1337                 goto fail;
1338         if (ret == 0)
1339                 root->orphan_item_inserted = 1;
1340
1341         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1342         if (ret)
1343                 goto fail;
1344
1345         spin_lock(&fs_info->fs_roots_radix_lock);
1346         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1347                                 (unsigned long)root->root_key.objectid,
1348                                 root);
1349         if (ret == 0)
1350                 root->in_radix = 1;
1351
1352         spin_unlock(&fs_info->fs_roots_radix_lock);
1353         radix_tree_preload_end();
1354         if (ret) {
1355                 if (ret == -EEXIST) {
1356                         free_fs_root(root);
1357                         goto again;
1358                 }
1359                 goto fail;
1360         }
1361
1362         ret = btrfs_find_dead_roots(fs_info->tree_root,
1363                                     root->root_key.objectid);
1364         WARN_ON(ret);
1365         return root;
1366 fail:
1367         free_fs_root(root);
1368         return ERR_PTR(ret);
1369 }
1370
1371 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
1372                                       struct btrfs_key *location,
1373                                       const char *name, int namelen)
1374 {
1375         return btrfs_read_fs_root_no_name(fs_info, location);
1376 #if 0
1377         struct btrfs_root *root;
1378         int ret;
1379
1380         root = btrfs_read_fs_root_no_name(fs_info, location);
1381         if (!root)
1382                 return NULL;
1383
1384         if (root->in_sysfs)
1385                 return root;
1386
1387         ret = btrfs_set_root_name(root, name, namelen);
1388         if (ret) {
1389                 free_extent_buffer(root->node);
1390                 kfree(root);
1391                 return ERR_PTR(ret);
1392         }
1393
1394         ret = btrfs_sysfs_add_root(root);
1395         if (ret) {
1396                 free_extent_buffer(root->node);
1397                 kfree(root->name);
1398                 kfree(root);
1399                 return ERR_PTR(ret);
1400         }
1401         root->in_sysfs = 1;
1402         return root;
1403 #endif
1404 }
1405
1406 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1407 {
1408         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1409         int ret = 0;
1410         struct btrfs_device *device;
1411         struct backing_dev_info *bdi;
1412
1413         list_for_each_entry(device, &info->fs_devices->devices, dev_list) {
1414                 if (!device->bdev)
1415                         continue;
1416                 bdi = blk_get_backing_dev_info(device->bdev);
1417                 if (bdi && bdi_congested(bdi, bdi_bits)) {
1418                         ret = 1;
1419                         break;
1420                 }
1421         }
1422         return ret;
1423 }
1424
1425 /*
1426  * this unplugs every device on the box, and it is only used when page
1427  * is null
1428  */
1429 static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1430 {
1431         struct btrfs_device *device;
1432         struct btrfs_fs_info *info;
1433
1434         info = (struct btrfs_fs_info *)bdi->unplug_io_data;
1435         list_for_each_entry(device, &info->fs_devices->devices, dev_list) {
1436                 if (!device->bdev)
1437                         continue;
1438
1439                 bdi = blk_get_backing_dev_info(device->bdev);
1440                 if (bdi->unplug_io_fn)
1441                         bdi->unplug_io_fn(bdi, page);
1442         }
1443 }
1444
1445 static void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1446 {
1447         struct inode *inode;
1448         struct extent_map_tree *em_tree;
1449         struct extent_map *em;
1450         struct address_space *mapping;
1451         u64 offset;
1452
1453         /* the generic O_DIRECT read code does this */
1454         if (1 || !page) {
1455                 __unplug_io_fn(bdi, page);
1456                 return;
1457         }
1458
1459         /*
1460          * page->mapping may change at any time.  Get a consistent copy
1461          * and use that for everything below
1462          */
1463         smp_mb();
1464         mapping = page->mapping;
1465         if (!mapping)
1466                 return;
1467
1468         inode = mapping->host;
1469
1470         /*
1471          * don't do the expensive searching for a small number of
1472          * devices
1473          */
1474         if (BTRFS_I(inode)->root->fs_info->fs_devices->open_devices <= 2) {
1475                 __unplug_io_fn(bdi, page);
1476                 return;
1477         }
1478
1479         offset = page_offset(page);
1480
1481         em_tree = &BTRFS_I(inode)->extent_tree;
1482         read_lock(&em_tree->lock);
1483         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
1484         read_unlock(&em_tree->lock);
1485         if (!em) {
1486                 __unplug_io_fn(bdi, page);
1487                 return;
1488         }
1489
1490         if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1491                 free_extent_map(em);
1492                 __unplug_io_fn(bdi, page);
1493                 return;
1494         }
1495         offset = offset - em->start;
1496         btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
1497                           em->block_start + offset, page);
1498         free_extent_map(em);
1499 }
1500
1501 /*
1502  * If this fails, caller must call bdi_destroy() to get rid of the
1503  * bdi again.
1504  */
1505 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1506 {
1507         int err;
1508
1509         bdi->capabilities = BDI_CAP_MAP_COPY;
1510         err = bdi_setup_and_register(bdi, "btrfs", BDI_CAP_MAP_COPY);
1511         if (err)
1512                 return err;
1513
1514         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1515         bdi->unplug_io_fn       = btrfs_unplug_io_fn;
1516         bdi->unplug_io_data     = info;
1517         bdi->congested_fn       = btrfs_congested_fn;
1518         bdi->congested_data     = info;
1519         return 0;
1520 }
1521
1522 static int bio_ready_for_csum(struct bio *bio)
1523 {
1524         u64 length = 0;
1525         u64 buf_len = 0;
1526         u64 start = 0;
1527         struct page *page;
1528         struct extent_io_tree *io_tree = NULL;
1529         struct bio_vec *bvec;
1530         int i;
1531         int ret;
1532
1533         bio_for_each_segment(bvec, bio, i) {
1534                 page = bvec->bv_page;
1535                 if (page->private == EXTENT_PAGE_PRIVATE) {
1536                         length += bvec->bv_len;
1537                         continue;
1538                 }
1539                 if (!page->private) {
1540                         length += bvec->bv_len;
1541                         continue;
1542                 }
1543                 length = bvec->bv_len;
1544                 buf_len = page->private >> 2;
1545                 start = page_offset(page) + bvec->bv_offset;
1546                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1547         }
1548         /* are we fully contained in this bio? */
1549         if (buf_len <= length)
1550                 return 1;
1551
1552         ret = extent_range_uptodate(io_tree, start + length,
1553                                     start + buf_len - 1);
1554         return ret;
1555 }
1556
1557 /*
1558  * called by the kthread helper functions to finally call the bio end_io
1559  * functions.  This is where read checksum verification actually happens
1560  */
1561 static void end_workqueue_fn(struct btrfs_work *work)
1562 {
1563         struct bio *bio;
1564         struct end_io_wq *end_io_wq;
1565         struct btrfs_fs_info *fs_info;
1566         int error;
1567
1568         end_io_wq = container_of(work, struct end_io_wq, work);
1569         bio = end_io_wq->bio;
1570         fs_info = end_io_wq->info;
1571
1572         /* metadata bio reads are special because the whole tree block must
1573          * be checksummed at once.  This makes sure the entire block is in
1574          * ram and up to date before trying to verify things.  For
1575          * blocksize <= pagesize, it is basically a noop
1576          */
1577         if (!(bio->bi_rw & REQ_WRITE) && end_io_wq->metadata &&
1578             !bio_ready_for_csum(bio)) {
1579                 btrfs_queue_worker(&fs_info->endio_meta_workers,
1580                                    &end_io_wq->work);
1581                 return;
1582         }
1583         error = end_io_wq->error;
1584         bio->bi_private = end_io_wq->private;
1585         bio->bi_end_io = end_io_wq->end_io;
1586         kfree(end_io_wq);
1587         bio_endio(bio, error);
1588 }
1589
1590 static int cleaner_kthread(void *arg)
1591 {
1592         struct btrfs_root *root = arg;
1593
1594         do {
1595                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1596
1597                 if (!(root->fs_info->sb->s_flags & MS_RDONLY) &&
1598                     mutex_trylock(&root->fs_info->cleaner_mutex)) {
1599                         btrfs_run_delayed_iputs(root);
1600                         btrfs_clean_old_snapshots(root);
1601                         mutex_unlock(&root->fs_info->cleaner_mutex);
1602                 }
1603
1604                 if (freezing(current)) {
1605                         refrigerator();
1606                 } else {
1607                         set_current_state(TASK_INTERRUPTIBLE);
1608                         if (!kthread_should_stop())
1609                                 schedule();
1610                         __set_current_state(TASK_RUNNING);
1611                 }
1612         } while (!kthread_should_stop());
1613         return 0;
1614 }
1615
1616 static int transaction_kthread(void *arg)
1617 {
1618         struct btrfs_root *root = arg;
1619         struct btrfs_trans_handle *trans;
1620         struct btrfs_transaction *cur;
1621         u64 transid;
1622         unsigned long now;
1623         unsigned long delay;
1624         int ret;
1625
1626         do {
1627                 delay = HZ * 30;
1628                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1629                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1630
1631                 spin_lock(&root->fs_info->new_trans_lock);
1632                 cur = root->fs_info->running_transaction;
1633                 if (!cur) {
1634                         spin_unlock(&root->fs_info->new_trans_lock);
1635                         goto sleep;
1636                 }
1637
1638                 now = get_seconds();
1639                 if (!cur->blocked &&
1640                     (now < cur->start_time || now - cur->start_time < 30)) {
1641                         spin_unlock(&root->fs_info->new_trans_lock);
1642                         delay = HZ * 5;
1643                         goto sleep;
1644                 }
1645                 transid = cur->transid;
1646                 spin_unlock(&root->fs_info->new_trans_lock);
1647
1648                 trans = btrfs_join_transaction(root, 1);
1649                 BUG_ON(IS_ERR(trans));
1650                 if (transid == trans->transid) {
1651                         ret = btrfs_commit_transaction(trans, root);
1652                         BUG_ON(ret);
1653                 } else {
1654                         btrfs_end_transaction(trans, root);
1655                 }
1656 sleep:
1657                 wake_up_process(root->fs_info->cleaner_kthread);
1658                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1659
1660                 if (freezing(current)) {
1661                         refrigerator();
1662                 } else {
1663                         set_current_state(TASK_INTERRUPTIBLE);
1664                         if (!kthread_should_stop() &&
1665                             !btrfs_transaction_blocked(root->fs_info))
1666                                 schedule_timeout(delay);
1667                         __set_current_state(TASK_RUNNING);
1668                 }
1669         } while (!kthread_should_stop());
1670         return 0;
1671 }
1672
1673 struct btrfs_root *open_ctree(struct super_block *sb,
1674                               struct btrfs_fs_devices *fs_devices,
1675                               char *options)
1676 {
1677         u32 sectorsize;
1678         u32 nodesize;
1679         u32 leafsize;
1680         u32 blocksize;
1681         u32 stripesize;
1682         u64 generation;
1683         u64 features;
1684         struct btrfs_key location;
1685         struct buffer_head *bh;
1686         struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
1687                                                  GFP_NOFS);
1688         struct btrfs_root *csum_root = kzalloc(sizeof(struct btrfs_root),
1689                                                  GFP_NOFS);
1690         struct btrfs_root *tree_root = btrfs_sb(sb);
1691         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1692         struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
1693                                                 GFP_NOFS);
1694         struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
1695                                               GFP_NOFS);
1696         struct btrfs_root *log_tree_root;
1697
1698         int ret;
1699         int err = -EINVAL;
1700
1701         struct btrfs_super_block *disk_super;
1702
1703         if (!extent_root || !tree_root || !fs_info ||
1704             !chunk_root || !dev_root || !csum_root) {
1705                 err = -ENOMEM;
1706                 goto fail;
1707         }
1708
1709         ret = init_srcu_struct(&fs_info->subvol_srcu);
1710         if (ret) {
1711                 err = ret;
1712                 goto fail;
1713         }
1714
1715         ret = setup_bdi(fs_info, &fs_info->bdi);
1716         if (ret) {
1717                 err = ret;
1718                 goto fail_srcu;
1719         }
1720
1721         fs_info->btree_inode = new_inode(sb);
1722         if (!fs_info->btree_inode) {
1723                 err = -ENOMEM;
1724                 goto fail_bdi;
1725         }
1726
1727         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
1728         INIT_LIST_HEAD(&fs_info->trans_list);
1729         INIT_LIST_HEAD(&fs_info->dead_roots);
1730         INIT_LIST_HEAD(&fs_info->delayed_iputs);
1731         INIT_LIST_HEAD(&fs_info->hashers);
1732         INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1733         INIT_LIST_HEAD(&fs_info->ordered_operations);
1734         INIT_LIST_HEAD(&fs_info->caching_block_groups);
1735         spin_lock_init(&fs_info->delalloc_lock);
1736         spin_lock_init(&fs_info->new_trans_lock);
1737         spin_lock_init(&fs_info->ref_cache_lock);
1738         spin_lock_init(&fs_info->fs_roots_radix_lock);
1739         spin_lock_init(&fs_info->delayed_iput_lock);
1740
1741         init_completion(&fs_info->kobj_unregister);
1742         fs_info->tree_root = tree_root;
1743         fs_info->extent_root = extent_root;
1744         fs_info->csum_root = csum_root;
1745         fs_info->chunk_root = chunk_root;
1746         fs_info->dev_root = dev_root;
1747         fs_info->fs_devices = fs_devices;
1748         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1749         INIT_LIST_HEAD(&fs_info->space_info);
1750         btrfs_mapping_init(&fs_info->mapping_tree);
1751         btrfs_init_block_rsv(&fs_info->global_block_rsv);
1752         btrfs_init_block_rsv(&fs_info->delalloc_block_rsv);
1753         btrfs_init_block_rsv(&fs_info->trans_block_rsv);
1754         btrfs_init_block_rsv(&fs_info->chunk_block_rsv);
1755         btrfs_init_block_rsv(&fs_info->empty_block_rsv);
1756         INIT_LIST_HEAD(&fs_info->durable_block_rsv_list);
1757         mutex_init(&fs_info->durable_block_rsv_mutex);
1758         atomic_set(&fs_info->nr_async_submits, 0);
1759         atomic_set(&fs_info->async_delalloc_pages, 0);
1760         atomic_set(&fs_info->async_submit_draining, 0);
1761         atomic_set(&fs_info->nr_async_bios, 0);
1762         fs_info->sb = sb;
1763         fs_info->max_inline = 8192 * 1024;
1764         fs_info->metadata_ratio = 0;
1765
1766         fs_info->thread_pool_size = min_t(unsigned long,
1767                                           num_online_cpus() + 2, 8);
1768
1769         INIT_LIST_HEAD(&fs_info->ordered_extents);
1770         spin_lock_init(&fs_info->ordered_extent_lock);
1771
1772         sb->s_blocksize = 4096;
1773         sb->s_blocksize_bits = blksize_bits(4096);
1774         sb->s_bdi = &fs_info->bdi;
1775
1776         fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
1777         fs_info->btree_inode->i_nlink = 1;
1778         /*
1779          * we set the i_size on the btree inode to the max possible int.
1780          * the real end of the address space is determined by all of
1781          * the devices in the system
1782          */
1783         fs_info->btree_inode->i_size = OFFSET_MAX;
1784         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1785         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1786
1787         RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
1788         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1789                              fs_info->btree_inode->i_mapping,
1790                              GFP_NOFS);
1791         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1792                              GFP_NOFS);
1793
1794         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1795
1796         BTRFS_I(fs_info->btree_inode)->root = tree_root;
1797         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1798                sizeof(struct btrfs_key));
1799         BTRFS_I(fs_info->btree_inode)->dummy_inode = 1;
1800         insert_inode_hash(fs_info->btree_inode);
1801
1802         spin_lock_init(&fs_info->block_group_cache_lock);
1803         fs_info->block_group_cache_tree = RB_ROOT;
1804
1805         extent_io_tree_init(&fs_info->freed_extents[0],
1806                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1807         extent_io_tree_init(&fs_info->freed_extents[1],
1808                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1809         fs_info->pinned_extents = &fs_info->freed_extents[0];
1810         fs_info->do_barriers = 1;
1811
1812
1813         mutex_init(&fs_info->trans_mutex);
1814         mutex_init(&fs_info->ordered_operations_mutex);
1815         mutex_init(&fs_info->tree_log_mutex);
1816         mutex_init(&fs_info->chunk_mutex);
1817         mutex_init(&fs_info->transaction_kthread_mutex);
1818         mutex_init(&fs_info->cleaner_mutex);
1819         mutex_init(&fs_info->volume_mutex);
1820         init_rwsem(&fs_info->extent_commit_sem);
1821         init_rwsem(&fs_info->cleanup_work_sem);
1822         init_rwsem(&fs_info->subvol_sem);
1823
1824         btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
1825         btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
1826
1827         init_waitqueue_head(&fs_info->transaction_throttle);
1828         init_waitqueue_head(&fs_info->transaction_wait);
1829         init_waitqueue_head(&fs_info->transaction_blocked_wait);
1830         init_waitqueue_head(&fs_info->async_submit_wait);
1831
1832         __setup_root(4096, 4096, 4096, 4096, tree_root,
1833                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
1834
1835         bh = btrfs_read_dev_super(fs_devices->latest_bdev);
1836         if (!bh) {
1837                 err = -EINVAL;
1838                 goto fail_iput;
1839         }
1840
1841         memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1842         memcpy(&fs_info->super_for_commit, &fs_info->super_copy,
1843                sizeof(fs_info->super_for_commit));
1844         brelse(bh);
1845
1846         memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1847
1848         disk_super = &fs_info->super_copy;
1849         if (!btrfs_super_root(disk_super))
1850                 goto fail_iput;
1851
1852         /* check FS state, whether FS is broken. */
1853         fs_info->fs_state |= btrfs_super_flags(disk_super);
1854
1855         btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
1856
1857         /*
1858          * In the long term, we'll store the compression type in the super
1859          * block, and it'll be used for per file compression control.
1860          */
1861         fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
1862
1863         ret = btrfs_parse_options(tree_root, options);
1864         if (ret) {
1865                 err = ret;
1866                 goto fail_iput;
1867         }
1868
1869         features = btrfs_super_incompat_flags(disk_super) &
1870                 ~BTRFS_FEATURE_INCOMPAT_SUPP;
1871         if (features) {
1872                 printk(KERN_ERR "BTRFS: couldn't mount because of "
1873                        "unsupported optional features (%Lx).\n",
1874                        (unsigned long long)features);
1875                 err = -EINVAL;
1876                 goto fail_iput;
1877         }
1878
1879         features = btrfs_super_incompat_flags(disk_super);
1880         features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
1881         if (tree_root->fs_info->compress_type & BTRFS_COMPRESS_LZO)
1882                 features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
1883         btrfs_set_super_incompat_flags(disk_super, features);
1884
1885         features = btrfs_super_compat_ro_flags(disk_super) &
1886                 ~BTRFS_FEATURE_COMPAT_RO_SUPP;
1887         if (!(sb->s_flags & MS_RDONLY) && features) {
1888                 printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
1889                        "unsupported option features (%Lx).\n",
1890                        (unsigned long long)features);
1891                 err = -EINVAL;
1892                 goto fail_iput;
1893         }
1894
1895         btrfs_init_workers(&fs_info->generic_worker,
1896                            "genwork", 1, NULL);
1897
1898         btrfs_init_workers(&fs_info->workers, "worker",
1899                            fs_info->thread_pool_size,
1900                            &fs_info->generic_worker);
1901
1902         btrfs_init_workers(&fs_info->delalloc_workers, "delalloc",
1903                            fs_info->thread_pool_size,
1904                            &fs_info->generic_worker);
1905
1906         btrfs_init_workers(&fs_info->submit_workers, "submit",
1907                            min_t(u64, fs_devices->num_devices,
1908                            fs_info->thread_pool_size),
1909                            &fs_info->generic_worker);
1910
1911         /* a higher idle thresh on the submit workers makes it much more
1912          * likely that bios will be send down in a sane order to the
1913          * devices
1914          */
1915         fs_info->submit_workers.idle_thresh = 64;
1916
1917         fs_info->workers.idle_thresh = 16;
1918         fs_info->workers.ordered = 1;
1919
1920         fs_info->delalloc_workers.idle_thresh = 2;
1921         fs_info->delalloc_workers.ordered = 1;
1922
1923         btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
1924                            &fs_info->generic_worker);
1925         btrfs_init_workers(&fs_info->endio_workers, "endio",
1926                            fs_info->thread_pool_size,
1927                            &fs_info->generic_worker);
1928         btrfs_init_workers(&fs_info->endio_meta_workers, "endio-meta",
1929                            fs_info->thread_pool_size,
1930                            &fs_info->generic_worker);
1931         btrfs_init_workers(&fs_info->endio_meta_write_workers,
1932                            "endio-meta-write", fs_info->thread_pool_size,
1933                            &fs_info->generic_worker);
1934         btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
1935                            fs_info->thread_pool_size,
1936                            &fs_info->generic_worker);
1937         btrfs_init_workers(&fs_info->endio_freespace_worker, "freespace-write",
1938                            1, &fs_info->generic_worker);
1939
1940         /*
1941          * endios are largely parallel and should have a very
1942          * low idle thresh
1943          */
1944         fs_info->endio_workers.idle_thresh = 4;
1945         fs_info->endio_meta_workers.idle_thresh = 4;
1946
1947         fs_info->endio_write_workers.idle_thresh = 2;
1948         fs_info->endio_meta_write_workers.idle_thresh = 2;
1949
1950         btrfs_start_workers(&fs_info->workers, 1);
1951         btrfs_start_workers(&fs_info->generic_worker, 1);
1952         btrfs_start_workers(&fs_info->submit_workers, 1);
1953         btrfs_start_workers(&fs_info->delalloc_workers, 1);
1954         btrfs_start_workers(&fs_info->fixup_workers, 1);
1955         btrfs_start_workers(&fs_info->endio_workers, 1);
1956         btrfs_start_workers(&fs_info->endio_meta_workers, 1);
1957         btrfs_start_workers(&fs_info->endio_meta_write_workers, 1);
1958         btrfs_start_workers(&fs_info->endio_write_workers, 1);
1959         btrfs_start_workers(&fs_info->endio_freespace_worker, 1);
1960
1961         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1962         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
1963                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
1964
1965         nodesize = btrfs_super_nodesize(disk_super);
1966         leafsize = btrfs_super_leafsize(disk_super);
1967         sectorsize = btrfs_super_sectorsize(disk_super);
1968         stripesize = btrfs_super_stripesize(disk_super);
1969         tree_root->nodesize = nodesize;
1970         tree_root->leafsize = leafsize;
1971         tree_root->sectorsize = sectorsize;
1972         tree_root->stripesize = stripesize;
1973
1974         sb->s_blocksize = sectorsize;
1975         sb->s_blocksize_bits = blksize_bits(sectorsize);
1976
1977         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1978                     sizeof(disk_super->magic))) {
1979                 printk(KERN_INFO "btrfs: valid FS not found on %s\n", sb->s_id);
1980                 goto fail_sb_buffer;
1981         }
1982
1983         mutex_lock(&fs_info->chunk_mutex);
1984         ret = btrfs_read_sys_array(tree_root);
1985         mutex_unlock(&fs_info->chunk_mutex);
1986         if (ret) {
1987                 printk(KERN_WARNING "btrfs: failed to read the system "
1988                        "array on %s\n", sb->s_id);
1989                 goto fail_sb_buffer;
1990         }
1991
1992         blocksize = btrfs_level_size(tree_root,
1993                                      btrfs_super_chunk_root_level(disk_super));
1994         generation = btrfs_super_chunk_root_generation(disk_super);
1995
1996         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1997                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1998
1999         chunk_root->node = read_tree_block(chunk_root,
2000                                            btrfs_super_chunk_root(disk_super),
2001                                            blocksize, generation);
2002         BUG_ON(!chunk_root->node);
2003         if (!test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
2004                 printk(KERN_WARNING "btrfs: failed to read chunk root on %s\n",
2005                        sb->s_id);
2006                 goto fail_chunk_root;
2007         }
2008         btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
2009         chunk_root->commit_root = btrfs_root_node(chunk_root);
2010
2011         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
2012            (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
2013            BTRFS_UUID_SIZE);
2014
2015         mutex_lock(&fs_info->chunk_mutex);
2016         ret = btrfs_read_chunk_tree(chunk_root);
2017         mutex_unlock(&fs_info->chunk_mutex);
2018         if (ret) {
2019                 printk(KERN_WARNING "btrfs: failed to read chunk tree on %s\n",
2020                        sb->s_id);
2021                 goto fail_chunk_root;
2022         }
2023
2024         btrfs_close_extra_devices(fs_devices);
2025
2026         blocksize = btrfs_level_size(tree_root,
2027                                      btrfs_super_root_level(disk_super));
2028         generation = btrfs_super_generation(disk_super);
2029
2030         tree_root->node = read_tree_block(tree_root,
2031                                           btrfs_super_root(disk_super),
2032                                           blocksize, generation);
2033         if (!tree_root->node)
2034                 goto fail_chunk_root;
2035         if (!test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
2036                 printk(KERN_WARNING "btrfs: failed to read tree root on %s\n",
2037                        sb->s_id);
2038                 goto fail_tree_root;
2039         }
2040         btrfs_set_root_node(&tree_root->root_item, tree_root->node);
2041         tree_root->commit_root = btrfs_root_node(tree_root);
2042
2043         ret = find_and_setup_root(tree_root, fs_info,
2044                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
2045         if (ret)
2046                 goto fail_tree_root;
2047         extent_root->track_dirty = 1;
2048
2049         ret = find_and_setup_root(tree_root, fs_info,
2050                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
2051         if (ret)
2052                 goto fail_extent_root;
2053         dev_root->track_dirty = 1;
2054
2055         ret = find_and_setup_root(tree_root, fs_info,
2056                                   BTRFS_CSUM_TREE_OBJECTID, csum_root);
2057         if (ret)
2058                 goto fail_dev_root;
2059
2060         csum_root->track_dirty = 1;
2061
2062         fs_info->generation = generation;
2063         fs_info->last_trans_committed = generation;
2064         fs_info->data_alloc_profile = (u64)-1;
2065         fs_info->metadata_alloc_profile = (u64)-1;
2066         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
2067
2068         ret = btrfs_read_block_groups(extent_root);
2069         if (ret) {
2070                 printk(KERN_ERR "Failed to read block groups: %d\n", ret);
2071                 goto fail_block_groups;
2072         }
2073
2074         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
2075                                                "btrfs-cleaner");
2076         if (IS_ERR(fs_info->cleaner_kthread))
2077                 goto fail_block_groups;
2078
2079         fs_info->transaction_kthread = kthread_run(transaction_kthread,
2080                                                    tree_root,
2081                                                    "btrfs-transaction");
2082         if (IS_ERR(fs_info->transaction_kthread))
2083                 goto fail_cleaner;
2084
2085         if (!btrfs_test_opt(tree_root, SSD) &&
2086             !btrfs_test_opt(tree_root, NOSSD) &&
2087             !fs_info->fs_devices->rotating) {
2088                 printk(KERN_INFO "Btrfs detected SSD devices, enabling SSD "
2089                        "mode\n");
2090                 btrfs_set_opt(fs_info->mount_opt, SSD);
2091         }
2092
2093         /* do not make disk changes in broken FS */
2094         if (btrfs_super_log_root(disk_super) != 0 &&
2095             !(fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)) {
2096                 u64 bytenr = btrfs_super_log_root(disk_super);
2097
2098                 if (fs_devices->rw_devices == 0) {
2099                         printk(KERN_WARNING "Btrfs log replay required "
2100                                "on RO media\n");
2101                         err = -EIO;
2102                         goto fail_trans_kthread;
2103                 }
2104                 blocksize =
2105                      btrfs_level_size(tree_root,
2106                                       btrfs_super_log_root_level(disk_super));
2107
2108                 log_tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
2109                 if (!log_tree_root) {
2110                         err = -ENOMEM;
2111                         goto fail_trans_kthread;
2112                 }
2113
2114                 __setup_root(nodesize, leafsize, sectorsize, stripesize,
2115                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
2116
2117                 log_tree_root->node = read_tree_block(tree_root, bytenr,
2118                                                       blocksize,
2119                                                       generation + 1);
2120                 ret = btrfs_recover_log_trees(log_tree_root);
2121                 BUG_ON(ret);
2122
2123                 if (sb->s_flags & MS_RDONLY) {
2124                         ret =  btrfs_commit_super(tree_root);
2125                         BUG_ON(ret);
2126                 }
2127         }
2128
2129         ret = btrfs_find_orphan_roots(tree_root);
2130         BUG_ON(ret);
2131
2132         if (!(sb->s_flags & MS_RDONLY)) {
2133                 ret = btrfs_cleanup_fs_roots(fs_info);
2134                 BUG_ON(ret);
2135
2136                 ret = btrfs_recover_relocation(tree_root);
2137                 if (ret < 0) {
2138                         printk(KERN_WARNING
2139                                "btrfs: failed to recover relocation\n");
2140                         err = -EINVAL;
2141                         goto fail_trans_kthread;
2142                 }
2143         }
2144
2145         location.objectid = BTRFS_FS_TREE_OBJECTID;
2146         location.type = BTRFS_ROOT_ITEM_KEY;
2147         location.offset = (u64)-1;
2148
2149         fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
2150         if (!fs_info->fs_root)
2151                 goto fail_trans_kthread;
2152         if (IS_ERR(fs_info->fs_root)) {
2153                 err = PTR_ERR(fs_info->fs_root);
2154                 goto fail_trans_kthread;
2155         }
2156
2157         if (!(sb->s_flags & MS_RDONLY)) {
2158                 down_read(&fs_info->cleanup_work_sem);
2159                 err = btrfs_orphan_cleanup(fs_info->fs_root);
2160                 if (!err)
2161                         err = btrfs_orphan_cleanup(fs_info->tree_root);
2162                 up_read(&fs_info->cleanup_work_sem);
2163                 if (err) {
2164                         close_ctree(tree_root);
2165                         return ERR_PTR(err);
2166                 }
2167         }
2168
2169         return tree_root;
2170
2171 fail_trans_kthread:
2172         kthread_stop(fs_info->transaction_kthread);
2173 fail_cleaner:
2174         kthread_stop(fs_info->cleaner_kthread);
2175
2176         /*
2177          * make sure we're done with the btree inode before we stop our
2178          * kthreads
2179          */
2180         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
2181         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2182
2183 fail_block_groups:
2184         btrfs_free_block_groups(fs_info);
2185         free_extent_buffer(csum_root->node);
2186         free_extent_buffer(csum_root->commit_root);
2187 fail_dev_root:
2188         free_extent_buffer(dev_root->node);
2189         free_extent_buffer(dev_root->commit_root);
2190 fail_extent_root:
2191         free_extent_buffer(extent_root->node);
2192         free_extent_buffer(extent_root->commit_root);
2193 fail_tree_root:
2194         free_extent_buffer(tree_root->node);
2195         free_extent_buffer(tree_root->commit_root);
2196 fail_chunk_root:
2197         free_extent_buffer(chunk_root->node);
2198         free_extent_buffer(chunk_root->commit_root);
2199 fail_sb_buffer:
2200         btrfs_stop_workers(&fs_info->generic_worker);
2201         btrfs_stop_workers(&fs_info->fixup_workers);
2202         btrfs_stop_workers(&fs_info->delalloc_workers);
2203         btrfs_stop_workers(&fs_info->workers);
2204         btrfs_stop_workers(&fs_info->endio_workers);
2205         btrfs_stop_workers(&fs_info->endio_meta_workers);
2206         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2207         btrfs_stop_workers(&fs_info->endio_write_workers);
2208         btrfs_stop_workers(&fs_info->endio_freespace_worker);
2209         btrfs_stop_workers(&fs_info->submit_workers);
2210 fail_iput:
2211         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2212         iput(fs_info->btree_inode);
2213
2214         btrfs_close_devices(fs_info->fs_devices);
2215         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2216 fail_bdi:
2217         bdi_destroy(&fs_info->bdi);
2218 fail_srcu:
2219         cleanup_srcu_struct(&fs_info->subvol_srcu);
2220 fail:
2221         kfree(extent_root);
2222         kfree(tree_root);
2223         kfree(fs_info);
2224         kfree(chunk_root);
2225         kfree(dev_root);
2226         kfree(csum_root);
2227         return ERR_PTR(err);
2228 }
2229
2230 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
2231 {
2232         char b[BDEVNAME_SIZE];
2233
2234         if (uptodate) {
2235                 set_buffer_uptodate(bh);
2236         } else {
2237                 if (printk_ratelimit()) {
2238                         printk(KERN_WARNING "lost page write due to "
2239                                         "I/O error on %s\n",
2240                                        bdevname(bh->b_bdev, b));
2241                 }
2242                 /* note, we dont' set_buffer_write_io_error because we have
2243                  * our own ways of dealing with the IO errors
2244                  */
2245                 clear_buffer_uptodate(bh);
2246         }
2247         unlock_buffer(bh);
2248         put_bh(bh);
2249 }
2250
2251 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
2252 {
2253         struct buffer_head *bh;
2254         struct buffer_head *latest = NULL;
2255         struct btrfs_super_block *super;
2256         int i;
2257         u64 transid = 0;
2258         u64 bytenr;
2259
2260         /* we would like to check all the supers, but that would make
2261          * a btrfs mount succeed after a mkfs from a different FS.
2262          * So, we need to add a special mount option to scan for
2263          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
2264          */
2265         for (i = 0; i < 1; i++) {
2266                 bytenr = btrfs_sb_offset(i);
2267                 if (bytenr + 4096 >= i_size_read(bdev->bd_inode))
2268                         break;
2269                 bh = __bread(bdev, bytenr / 4096, 4096);
2270                 if (!bh)
2271                         continue;
2272
2273                 super = (struct btrfs_super_block *)bh->b_data;
2274                 if (btrfs_super_bytenr(super) != bytenr ||
2275                     strncmp((char *)(&super->magic), BTRFS_MAGIC,
2276                             sizeof(super->magic))) {
2277                         brelse(bh);
2278                         continue;
2279                 }
2280
2281                 if (!latest || btrfs_super_generation(super) > transid) {
2282                         brelse(latest);
2283                         latest = bh;
2284                         transid = btrfs_super_generation(super);
2285                 } else {
2286                         brelse(bh);
2287                 }
2288         }
2289         return latest;
2290 }
2291
2292 /*
2293  * this should be called twice, once with wait == 0 and
2294  * once with wait == 1.  When wait == 0 is done, all the buffer heads
2295  * we write are pinned.
2296  *
2297  * They are released when wait == 1 is done.
2298  * max_mirrors must be the same for both runs, and it indicates how
2299  * many supers on this one device should be written.
2300  *
2301  * max_mirrors == 0 means to write them all.
2302  */
2303 static int write_dev_supers(struct btrfs_device *device,
2304                             struct btrfs_super_block *sb,
2305                             int do_barriers, int wait, int max_mirrors)
2306 {
2307         struct buffer_head *bh;
2308         int i;
2309         int ret;
2310         int errors = 0;
2311         u32 crc;
2312         u64 bytenr;
2313         int last_barrier = 0;
2314
2315         if (max_mirrors == 0)
2316                 max_mirrors = BTRFS_SUPER_MIRROR_MAX;
2317
2318         /* make sure only the last submit_bh does a barrier */
2319         if (do_barriers) {
2320                 for (i = 0; i < max_mirrors; i++) {
2321                         bytenr = btrfs_sb_offset(i);
2322                         if (bytenr + BTRFS_SUPER_INFO_SIZE >=
2323                             device->total_bytes)
2324                                 break;
2325                         last_barrier = i;
2326                 }
2327         }
2328
2329         for (i = 0; i < max_mirrors; i++) {
2330                 bytenr = btrfs_sb_offset(i);
2331                 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
2332                         break;
2333
2334                 if (wait) {
2335                         bh = __find_get_block(device->bdev, bytenr / 4096,
2336                                               BTRFS_SUPER_INFO_SIZE);
2337                         BUG_ON(!bh);
2338                         wait_on_buffer(bh);
2339                         if (!buffer_uptodate(bh))
2340                                 errors++;
2341
2342                         /* drop our reference */
2343                         brelse(bh);
2344
2345                         /* drop the reference from the wait == 0 run */
2346                         brelse(bh);
2347                         continue;
2348                 } else {
2349                         btrfs_set_super_bytenr(sb, bytenr);
2350
2351                         crc = ~(u32)0;
2352                         crc = btrfs_csum_data(NULL, (char *)sb +
2353                                               BTRFS_CSUM_SIZE, crc,
2354                                               BTRFS_SUPER_INFO_SIZE -
2355                                               BTRFS_CSUM_SIZE);
2356                         btrfs_csum_final(crc, sb->csum);
2357
2358                         /*
2359                          * one reference for us, and we leave it for the
2360                          * caller
2361                          */
2362                         bh = __getblk(device->bdev, bytenr / 4096,
2363                                       BTRFS_SUPER_INFO_SIZE);
2364                         memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
2365
2366                         /* one reference for submit_bh */
2367                         get_bh(bh);
2368
2369                         set_buffer_uptodate(bh);
2370                         lock_buffer(bh);
2371                         bh->b_end_io = btrfs_end_buffer_write_sync;
2372                 }
2373
2374                 if (i == last_barrier && do_barriers)
2375                         ret = submit_bh(WRITE_FLUSH_FUA, bh);
2376                 else
2377                         ret = submit_bh(WRITE_SYNC, bh);
2378
2379                 if (ret)
2380                         errors++;
2381         }
2382         return errors < i ? 0 : -1;
2383 }
2384
2385 int write_all_supers(struct btrfs_root *root, int max_mirrors)
2386 {
2387         struct list_head *head;
2388         struct btrfs_device *dev;
2389         struct btrfs_super_block *sb;
2390         struct btrfs_dev_item *dev_item;
2391         int ret;
2392         int do_barriers;
2393         int max_errors;
2394         int total_errors = 0;
2395         u64 flags;
2396
2397         max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
2398         do_barriers = !btrfs_test_opt(root, NOBARRIER);
2399
2400         sb = &root->fs_info->super_for_commit;
2401         dev_item = &sb->dev_item;
2402
2403         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2404         head = &root->fs_info->fs_devices->devices;
2405         list_for_each_entry(dev, head, dev_list) {
2406                 if (!dev->bdev) {
2407                         total_errors++;
2408                         continue;
2409                 }
2410                 if (!dev->in_fs_metadata || !dev->writeable)
2411                         continue;
2412
2413                 btrfs_set_stack_device_generation(dev_item, 0);
2414                 btrfs_set_stack_device_type(dev_item, dev->type);
2415                 btrfs_set_stack_device_id(dev_item, dev->devid);
2416                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
2417                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
2418                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
2419                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
2420                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
2421                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
2422                 memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
2423
2424                 flags = btrfs_super_flags(sb);
2425                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
2426
2427                 ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
2428                 if (ret)
2429                         total_errors++;
2430         }
2431         if (total_errors > max_errors) {
2432                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2433                        total_errors);
2434                 BUG();
2435         }
2436
2437         total_errors = 0;
2438         list_for_each_entry(dev, head, dev_list) {
2439                 if (!dev->bdev)
2440                         continue;
2441                 if (!dev->in_fs_metadata || !dev->writeable)
2442                         continue;
2443
2444                 ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
2445                 if (ret)
2446                         total_errors++;
2447         }
2448         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2449         if (total_errors > max_errors) {
2450                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2451                        total_errors);
2452                 BUG();
2453         }
2454         return 0;
2455 }
2456
2457 int write_ctree_super(struct btrfs_trans_handle *trans,
2458                       struct btrfs_root *root, int max_mirrors)
2459 {
2460         int ret;
2461
2462         ret = write_all_supers(root, max_mirrors);
2463         return ret;
2464 }
2465
2466 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2467 {
2468         spin_lock(&fs_info->fs_roots_radix_lock);
2469         radix_tree_delete(&fs_info->fs_roots_radix,
2470                           (unsigned long)root->root_key.objectid);
2471         spin_unlock(&fs_info->fs_roots_radix_lock);
2472
2473         if (btrfs_root_refs(&root->root_item) == 0)
2474                 synchronize_srcu(&fs_info->subvol_srcu);
2475
2476         free_fs_root(root);
2477         return 0;
2478 }
2479
2480 static void free_fs_root(struct btrfs_root *root)
2481 {
2482         WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
2483         if (root->anon_super.s_dev) {
2484                 down_write(&root->anon_super.s_umount);
2485                 kill_anon_super(&root->anon_super);
2486         }
2487         free_extent_buffer(root->node);
2488         free_extent_buffer(root->commit_root);
2489         kfree(root->name);
2490         kfree(root);
2491 }
2492
2493 static int del_fs_roots(struct btrfs_fs_info *fs_info)
2494 {
2495         int ret;
2496         struct btrfs_root *gang[8];
2497         int i;
2498
2499         while (!list_empty(&fs_info->dead_roots)) {
2500                 gang[0] = list_entry(fs_info->dead_roots.next,
2501                                      struct btrfs_root, root_list);
2502                 list_del(&gang[0]->root_list);
2503
2504                 if (gang[0]->in_radix) {
2505                         btrfs_free_fs_root(fs_info, gang[0]);
2506                 } else {
2507                         free_extent_buffer(gang[0]->node);
2508                         free_extent_buffer(gang[0]->commit_root);
2509                         kfree(gang[0]);
2510                 }
2511         }
2512
2513         while (1) {
2514                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2515                                              (void **)gang, 0,
2516                                              ARRAY_SIZE(gang));
2517                 if (!ret)
2518                         break;
2519                 for (i = 0; i < ret; i++)
2520                         btrfs_free_fs_root(fs_info, gang[i]);
2521         }
2522         return 0;
2523 }
2524
2525 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
2526 {
2527         u64 root_objectid = 0;
2528         struct btrfs_root *gang[8];
2529         int i;
2530         int ret;
2531
2532         while (1) {
2533                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2534                                              (void **)gang, root_objectid,
2535                                              ARRAY_SIZE(gang));
2536                 if (!ret)
2537                         break;
2538
2539                 root_objectid = gang[ret - 1]->root_key.objectid + 1;
2540                 for (i = 0; i < ret; i++) {
2541                         int err;
2542
2543                         root_objectid = gang[i]->root_key.objectid;
2544                         err = btrfs_orphan_cleanup(gang[i]);
2545                         if (err)
2546                                 return err;
2547                 }
2548                 root_objectid++;
2549         }
2550         return 0;
2551 }
2552
2553 int btrfs_commit_super(struct btrfs_root *root)
2554 {
2555         struct btrfs_trans_handle *trans;
2556         int ret;
2557
2558         mutex_lock(&root->fs_info->cleaner_mutex);
2559         btrfs_run_delayed_iputs(root);
2560         btrfs_clean_old_snapshots(root);
2561         mutex_unlock(&root->fs_info->cleaner_mutex);
2562
2563         /* wait until ongoing cleanup work done */
2564         down_write(&root->fs_info->cleanup_work_sem);
2565         up_write(&root->fs_info->cleanup_work_sem);
2566
2567         trans = btrfs_join_transaction(root, 1);
2568         if (IS_ERR(trans))
2569                 return PTR_ERR(trans);
2570         ret = btrfs_commit_transaction(trans, root);
2571         BUG_ON(ret);
2572         /* run commit again to drop the original snapshot */
2573         trans = btrfs_join_transaction(root, 1);
2574         if (IS_ERR(trans))
2575                 return PTR_ERR(trans);
2576         btrfs_commit_transaction(trans, root);
2577         ret = btrfs_write_and_wait_transaction(NULL, root);
2578         BUG_ON(ret);
2579
2580         ret = write_ctree_super(NULL, root, 0);
2581         return ret;
2582 }
2583
2584 int close_ctree(struct btrfs_root *root)
2585 {
2586         struct btrfs_fs_info *fs_info = root->fs_info;
2587         int ret;
2588
2589         fs_info->closing = 1;
2590         smp_mb();
2591
2592         btrfs_put_block_group_cache(fs_info);
2593
2594         /*
2595          * Here come 2 situations when btrfs is broken to flip readonly:
2596          *
2597          * 1. when btrfs flips readonly somewhere else before
2598          * btrfs_commit_super, sb->s_flags has MS_RDONLY flag,
2599          * and btrfs will skip to write sb directly to keep
2600          * ERROR state on disk.
2601          *
2602          * 2. when btrfs flips readonly just in btrfs_commit_super,
2603          * and in such case, btrfs cannnot write sb via btrfs_commit_super,
2604          * and since fs_state has been set BTRFS_SUPER_FLAG_ERROR flag,
2605          * btrfs will cleanup all FS resources first and write sb then.
2606          */
2607         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
2608                 ret = btrfs_commit_super(root);
2609                 if (ret)
2610                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
2611         }
2612
2613         if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
2614                 ret = btrfs_error_commit_super(root);
2615                 if (ret)
2616                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
2617         }
2618
2619         kthread_stop(root->fs_info->transaction_kthread);
2620         kthread_stop(root->fs_info->cleaner_kthread);
2621
2622         fs_info->closing = 2;
2623         smp_mb();
2624
2625         if (fs_info->delalloc_bytes) {
2626                 printk(KERN_INFO "btrfs: at unmount delalloc count %llu\n",
2627                        (unsigned long long)fs_info->delalloc_bytes);
2628         }
2629         if (fs_info->total_ref_cache_size) {
2630                 printk(KERN_INFO "btrfs: at umount reference cache size %llu\n",
2631                        (unsigned long long)fs_info->total_ref_cache_size);
2632         }
2633
2634         free_extent_buffer(fs_info->extent_root->node);
2635         free_extent_buffer(fs_info->extent_root->commit_root);
2636         free_extent_buffer(fs_info->tree_root->node);
2637         free_extent_buffer(fs_info->tree_root->commit_root);
2638         free_extent_buffer(root->fs_info->chunk_root->node);
2639         free_extent_buffer(root->fs_info->chunk_root->commit_root);
2640         free_extent_buffer(root->fs_info->dev_root->node);
2641         free_extent_buffer(root->fs_info->dev_root->commit_root);
2642         free_extent_buffer(root->fs_info->csum_root->node);
2643         free_extent_buffer(root->fs_info->csum_root->commit_root);
2644
2645         btrfs_free_block_groups(root->fs_info);
2646
2647         del_fs_roots(fs_info);
2648
2649         iput(fs_info->btree_inode);
2650
2651         btrfs_stop_workers(&fs_info->generic_worker);
2652         btrfs_stop_workers(&fs_info->fixup_workers);
2653         btrfs_stop_workers(&fs_info->delalloc_workers);
2654         btrfs_stop_workers(&fs_info->workers);
2655         btrfs_stop_workers(&fs_info->endio_workers);
2656         btrfs_stop_workers(&fs_info->endio_meta_workers);
2657         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2658         btrfs_stop_workers(&fs_info->endio_write_workers);
2659         btrfs_stop_workers(&fs_info->endio_freespace_worker);
2660         btrfs_stop_workers(&fs_info->submit_workers);
2661
2662         btrfs_close_devices(fs_info->fs_devices);
2663         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2664
2665         bdi_destroy(&fs_info->bdi);
2666         cleanup_srcu_struct(&fs_info->subvol_srcu);
2667
2668         kfree(fs_info->extent_root);
2669         kfree(fs_info->tree_root);
2670         kfree(fs_info->chunk_root);
2671         kfree(fs_info->dev_root);
2672         kfree(fs_info->csum_root);
2673         kfree(fs_info);
2674
2675         return 0;
2676 }
2677
2678 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
2679 {
2680         int ret;
2681         struct inode *btree_inode = buf->first_page->mapping->host;
2682
2683         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf,
2684                                      NULL);
2685         if (!ret)
2686                 return ret;
2687
2688         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
2689                                     parent_transid);
2690         return !ret;
2691 }
2692
2693 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
2694 {
2695         struct inode *btree_inode = buf->first_page->mapping->host;
2696         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
2697                                           buf);
2698 }
2699
2700 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
2701 {
2702         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2703         u64 transid = btrfs_header_generation(buf);
2704         struct inode *btree_inode = root->fs_info->btree_inode;
2705         int was_dirty;
2706
2707         btrfs_assert_tree_locked(buf);
2708         if (transid != root->fs_info->generation) {
2709                 printk(KERN_CRIT "btrfs transid mismatch buffer %llu, "
2710                        "found %llu running %llu\n",
2711                         (unsigned long long)buf->start,
2712                         (unsigned long long)transid,
2713                         (unsigned long long)root->fs_info->generation);
2714                 WARN_ON(1);
2715         }
2716         was_dirty = set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
2717                                             buf);
2718         if (!was_dirty) {
2719                 spin_lock(&root->fs_info->delalloc_lock);
2720                 root->fs_info->dirty_metadata_bytes += buf->len;
2721                 spin_unlock(&root->fs_info->delalloc_lock);
2722         }
2723 }
2724
2725 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
2726 {
2727         /*
2728          * looks as though older kernels can get into trouble with
2729          * this code, they end up stuck in balance_dirty_pages forever
2730          */
2731         u64 num_dirty;
2732         unsigned long thresh = 32 * 1024 * 1024;
2733
2734         if (current->flags & PF_MEMALLOC)
2735                 return;
2736
2737         num_dirty = root->fs_info->dirty_metadata_bytes;
2738
2739         if (num_dirty > thresh) {
2740                 balance_dirty_pages_ratelimited_nr(
2741                                    root->fs_info->btree_inode->i_mapping, 1);
2742         }
2743         return;
2744 }
2745
2746 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
2747 {
2748         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2749         int ret;
2750         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
2751         if (ret == 0)
2752                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
2753         return ret;
2754 }
2755
2756 int btree_lock_page_hook(struct page *page)
2757 {
2758         struct inode *inode = page->mapping->host;
2759         struct btrfs_root *root = BTRFS_I(inode)->root;
2760         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2761         struct extent_buffer *eb;
2762         unsigned long len;
2763         u64 bytenr = page_offset(page);
2764
2765         if (page->private == EXTENT_PAGE_PRIVATE)
2766                 goto out;
2767
2768         len = page->private >> 2;
2769         eb = find_extent_buffer(io_tree, bytenr, len, GFP_NOFS);
2770         if (!eb)
2771                 goto out;
2772
2773         btrfs_tree_lock(eb);
2774         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
2775
2776         if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
2777                 spin_lock(&root->fs_info->delalloc_lock);
2778                 if (root->fs_info->dirty_metadata_bytes >= eb->len)
2779                         root->fs_info->dirty_metadata_bytes -= eb->len;
2780                 else
2781                         WARN_ON(1);
2782                 spin_unlock(&root->fs_info->delalloc_lock);
2783         }
2784
2785         btrfs_tree_unlock(eb);
2786         free_extent_buffer(eb);
2787 out:
2788         lock_page(page);
2789         return 0;
2790 }
2791
2792 static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
2793                               int read_only)
2794 {
2795         if (read_only)
2796                 return;
2797
2798         if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
2799                 printk(KERN_WARNING "warning: mount fs with errors, "
2800                        "running btrfsck is recommended\n");
2801 }
2802
2803 int btrfs_error_commit_super(struct btrfs_root *root)
2804 {
2805         int ret;
2806
2807         mutex_lock(&root->fs_info->cleaner_mutex);
2808         btrfs_run_delayed_iputs(root);
2809         mutex_unlock(&root->fs_info->cleaner_mutex);
2810
2811         down_write(&root->fs_info->cleanup_work_sem);
2812         up_write(&root->fs_info->cleanup_work_sem);
2813
2814         /* cleanup FS via transaction */
2815         btrfs_cleanup_transaction(root);
2816
2817         ret = write_ctree_super(NULL, root, 0);
2818
2819         return ret;
2820 }
2821
2822 static int btrfs_destroy_ordered_operations(struct btrfs_root *root)
2823 {
2824         struct btrfs_inode *btrfs_inode;
2825         struct list_head splice;
2826
2827         INIT_LIST_HEAD(&splice);
2828
2829         mutex_lock(&root->fs_info->ordered_operations_mutex);
2830         spin_lock(&root->fs_info->ordered_extent_lock);
2831
2832         list_splice_init(&root->fs_info->ordered_operations, &splice);
2833         while (!list_empty(&splice)) {
2834                 btrfs_inode = list_entry(splice.next, struct btrfs_inode,
2835                                          ordered_operations);
2836
2837                 list_del_init(&btrfs_inode->ordered_operations);
2838
2839                 btrfs_invalidate_inodes(btrfs_inode->root);
2840         }
2841
2842         spin_unlock(&root->fs_info->ordered_extent_lock);
2843         mutex_unlock(&root->fs_info->ordered_operations_mutex);
2844
2845         return 0;
2846 }
2847
2848 static int btrfs_destroy_ordered_extents(struct btrfs_root *root)
2849 {
2850         struct list_head splice;
2851         struct btrfs_ordered_extent *ordered;
2852         struct inode *inode;
2853
2854         INIT_LIST_HEAD(&splice);
2855
2856         spin_lock(&root->fs_info->ordered_extent_lock);
2857
2858         list_splice_init(&root->fs_info->ordered_extents, &splice);
2859         while (!list_empty(&splice)) {
2860                 ordered = list_entry(splice.next, struct btrfs_ordered_extent,
2861                                      root_extent_list);
2862
2863                 list_del_init(&ordered->root_extent_list);
2864                 atomic_inc(&ordered->refs);
2865
2866                 /* the inode may be getting freed (in sys_unlink path). */
2867                 inode = igrab(ordered->inode);
2868
2869                 spin_unlock(&root->fs_info->ordered_extent_lock);
2870                 if (inode)
2871                         iput(inode);
2872
2873                 atomic_set(&ordered->refs, 1);
2874                 btrfs_put_ordered_extent(ordered);
2875
2876                 spin_lock(&root->fs_info->ordered_extent_lock);
2877         }
2878
2879         spin_unlock(&root->fs_info->ordered_extent_lock);
2880
2881         return 0;
2882 }
2883
2884 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
2885                                       struct btrfs_root *root)
2886 {
2887         struct rb_node *node;
2888         struct btrfs_delayed_ref_root *delayed_refs;
2889         struct btrfs_delayed_ref_node *ref;
2890         int ret = 0;
2891
2892         delayed_refs = &trans->delayed_refs;
2893
2894         spin_lock(&delayed_refs->lock);
2895         if (delayed_refs->num_entries == 0) {
2896                 printk(KERN_INFO "delayed_refs has NO entry\n");
2897                 return ret;
2898         }
2899
2900         node = rb_first(&delayed_refs->root);
2901         while (node) {
2902                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2903                 node = rb_next(node);
2904
2905                 ref->in_tree = 0;
2906                 rb_erase(&ref->rb_node, &delayed_refs->root);
2907                 delayed_refs->num_entries--;
2908
2909                 atomic_set(&ref->refs, 1);
2910                 if (btrfs_delayed_ref_is_head(ref)) {
2911                         struct btrfs_delayed_ref_head *head;
2912
2913                         head = btrfs_delayed_node_to_head(ref);
2914                         mutex_lock(&head->mutex);
2915                         kfree(head->extent_op);
2916                         delayed_refs->num_heads--;
2917                         if (list_empty(&head->cluster))
2918                                 delayed_refs->num_heads_ready--;
2919                         list_del_init(&head->cluster);
2920                         mutex_unlock(&head->mutex);
2921                 }
2922
2923                 spin_unlock(&delayed_refs->lock);
2924                 btrfs_put_delayed_ref(ref);
2925
2926                 cond_resched();
2927                 spin_lock(&delayed_refs->lock);
2928         }
2929
2930         spin_unlock(&delayed_refs->lock);
2931
2932         return ret;
2933 }
2934
2935 static int btrfs_destroy_pending_snapshots(struct btrfs_transaction *t)
2936 {
2937         struct btrfs_pending_snapshot *snapshot;
2938         struct list_head splice;
2939
2940         INIT_LIST_HEAD(&splice);
2941
2942         list_splice_init(&t->pending_snapshots, &splice);
2943
2944         while (!list_empty(&splice)) {
2945                 snapshot = list_entry(splice.next,
2946                                       struct btrfs_pending_snapshot,
2947                                       list);
2948
2949                 list_del_init(&snapshot->list);
2950
2951                 kfree(snapshot);
2952         }
2953
2954         return 0;
2955 }
2956
2957 static int btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
2958 {
2959         struct btrfs_inode *btrfs_inode;
2960         struct list_head splice;
2961
2962         INIT_LIST_HEAD(&splice);
2963
2964         list_splice_init(&root->fs_info->delalloc_inodes, &splice);
2965
2966         spin_lock(&root->fs_info->delalloc_lock);
2967
2968         while (!list_empty(&splice)) {
2969                 btrfs_inode = list_entry(splice.next, struct btrfs_inode,
2970                                     delalloc_inodes);
2971
2972                 list_del_init(&btrfs_inode->delalloc_inodes);
2973
2974                 btrfs_invalidate_inodes(btrfs_inode->root);
2975         }
2976
2977         spin_unlock(&root->fs_info->delalloc_lock);
2978
2979         return 0;
2980 }
2981
2982 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
2983                                         struct extent_io_tree *dirty_pages,
2984                                         int mark)
2985 {
2986         int ret;
2987         struct page *page;
2988         struct inode *btree_inode = root->fs_info->btree_inode;
2989         struct extent_buffer *eb;
2990         u64 start = 0;
2991         u64 end;
2992         u64 offset;
2993         unsigned long index;
2994
2995         while (1) {
2996                 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
2997                                             mark);
2998                 if (ret)
2999                         break;
3000
3001                 clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
3002                 while (start <= end) {
3003                         index = start >> PAGE_CACHE_SHIFT;
3004                         start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
3005                         page = find_get_page(btree_inode->i_mapping, index);
3006                         if (!page)
3007                                 continue;
3008                         offset = page_offset(page);
3009
3010                         spin_lock(&dirty_pages->buffer_lock);
3011                         eb = radix_tree_lookup(
3012                              &(&BTRFS_I(page->mapping->host)->io_tree)->buffer,
3013                                                offset >> PAGE_CACHE_SHIFT);
3014                         spin_unlock(&dirty_pages->buffer_lock);
3015                         if (eb) {
3016                                 ret = test_and_clear_bit(EXTENT_BUFFER_DIRTY,
3017                                                          &eb->bflags);
3018                                 atomic_set(&eb->refs, 1);
3019                         }
3020                         if (PageWriteback(page))
3021                                 end_page_writeback(page);
3022
3023                         lock_page(page);
3024                         if (PageDirty(page)) {
3025                                 clear_page_dirty_for_io(page);
3026                                 spin_lock_irq(&page->mapping->tree_lock);
3027                                 radix_tree_tag_clear(&page->mapping->page_tree,
3028                                                         page_index(page),
3029                                                         PAGECACHE_TAG_DIRTY);
3030                                 spin_unlock_irq(&page->mapping->tree_lock);
3031                         }
3032
3033                         page->mapping->a_ops->invalidatepage(page, 0);
3034                         unlock_page(page);
3035                 }
3036         }
3037
3038         return ret;
3039 }
3040
3041 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
3042                                        struct extent_io_tree *pinned_extents)
3043 {
3044         struct extent_io_tree *unpin;
3045         u64 start;
3046         u64 end;
3047         int ret;
3048
3049         unpin = pinned_extents;
3050         while (1) {
3051                 ret = find_first_extent_bit(unpin, 0, &start, &end,
3052                                             EXTENT_DIRTY);
3053                 if (ret)
3054                         break;
3055
3056                 /* opt_discard */
3057                 if (btrfs_test_opt(root, DISCARD))
3058                         ret = btrfs_error_discard_extent(root, start,
3059                                                          end + 1 - start,
3060                                                          NULL);
3061
3062                 clear_extent_dirty(unpin, start, end, GFP_NOFS);
3063                 btrfs_error_unpin_extent_range(root, start, end);
3064                 cond_resched();
3065         }
3066
3067         return 0;
3068 }
3069
3070 static int btrfs_cleanup_transaction(struct btrfs_root *root)
3071 {
3072         struct btrfs_transaction *t;
3073         LIST_HEAD(list);
3074
3075         WARN_ON(1);
3076
3077         mutex_lock(&root->fs_info->trans_mutex);
3078         mutex_lock(&root->fs_info->transaction_kthread_mutex);
3079
3080         list_splice_init(&root->fs_info->trans_list, &list);
3081         while (!list_empty(&list)) {
3082                 t = list_entry(list.next, struct btrfs_transaction, list);
3083                 if (!t)
3084                         break;
3085
3086                 btrfs_destroy_ordered_operations(root);
3087
3088                 btrfs_destroy_ordered_extents(root);
3089
3090                 btrfs_destroy_delayed_refs(t, root);
3091
3092                 btrfs_block_rsv_release(root,
3093                                         &root->fs_info->trans_block_rsv,
3094                                         t->dirty_pages.dirty_bytes);
3095
3096                 /* FIXME: cleanup wait for commit */
3097                 t->in_commit = 1;
3098                 t->blocked = 1;
3099                 if (waitqueue_active(&root->fs_info->transaction_blocked_wait))
3100                         wake_up(&root->fs_info->transaction_blocked_wait);
3101
3102                 t->blocked = 0;
3103                 if (waitqueue_active(&root->fs_info->transaction_wait))
3104                         wake_up(&root->fs_info->transaction_wait);
3105                 mutex_unlock(&root->fs_info->trans_mutex);
3106
3107                 mutex_lock(&root->fs_info->trans_mutex);
3108                 t->commit_done = 1;
3109                 if (waitqueue_active(&t->commit_wait))
3110                         wake_up(&t->commit_wait);
3111                 mutex_unlock(&root->fs_info->trans_mutex);
3112
3113                 mutex_lock(&root->fs_info->trans_mutex);
3114
3115                 btrfs_destroy_pending_snapshots(t);
3116
3117                 btrfs_destroy_delalloc_inodes(root);
3118
3119                 spin_lock(&root->fs_info->new_trans_lock);
3120                 root->fs_info->running_transaction = NULL;
3121                 spin_unlock(&root->fs_info->new_trans_lock);
3122
3123                 btrfs_destroy_marked_extents(root, &t->dirty_pages,
3124                                              EXTENT_DIRTY);
3125
3126                 btrfs_destroy_pinned_extent(root,
3127                                             root->fs_info->pinned_extents);
3128
3129                 t->use_count = 0;
3130                 list_del_init(&t->list);
3131                 memset(t, 0, sizeof(*t));
3132                 kmem_cache_free(btrfs_transaction_cachep, t);
3133         }
3134
3135         mutex_unlock(&root->fs_info->transaction_kthread_mutex);
3136         mutex_unlock(&root->fs_info->trans_mutex);
3137
3138         return 0;
3139 }
3140
3141 static struct extent_io_ops btree_extent_io_ops = {
3142         .write_cache_pages_lock_hook = btree_lock_page_hook,
3143         .readpage_end_io_hook = btree_readpage_end_io_hook,
3144         .submit_bio_hook = btree_submit_bio_hook,
3145         /* note we're sharing with inode.c for the merge bio hook */
3146         .merge_bio_hook = btrfs_merge_bio_hook,
3147 };