fs/btrfs/disk-io.c

   1 /*
   2  * Copyright (C) 2007 Oracle.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 #include <linux/fs.h>
  20 #include <linux/blkdev.h>
  21 #include <linux/scatterlist.h>
  22 #include <linux/swap.h>
  23 #include <linux/radix-tree.h>
  24 #include <linux/writeback.h>
  25 #include <linux/buffer_head.h>
  26 #include <linux/workqueue.h>
  27 #include <linux/kthread.h>
  28 #include <linux/freezer.h>
  29 #include <linux/crc32c.h>
  30 #include <linux/slab.h>
  31 #include <linux/migrate.h>
  32 #include "compat.h"
  33 #include "ctree.h"
  34 #include "disk-io.h"
  35 #include "transaction.h"
  36 #include "btrfs_inode.h"
  37 #include "volumes.h"
  38 #include "print-tree.h"
  39 #include "async-thread.h"
  40 #include "locking.h"
  41 #include "tree-log.h"
  42 #include "free-space-cache.h"
  43
  44 static struct extent_io_ops btree_extent_io_ops;
  45 static void end_workqueue_fn(struct btrfs_work *work);
  46 static void free_fs_root(struct btrfs_root *root);
  47
  48 /*
  49  * end_io_wq structs are used to do processing in task context when an IO is
  50  * complete.  This is used during reads to verify checksums, and it is used
  51  * by writes to insert metadata for new file extents after IO is complete.
  52  */
  53 struct end_io_wq {
  54         struct bio *bio;
  55         bio_end_io_t *end_io;
  56         void *private;
  57         struct btrfs_fs_info *info;
  58         int error;
  59         int metadata;
  60         struct list_head list;
  61         struct btrfs_work work;
  62 };
  63
  64 /*
  65  * async submit bios are used to offload expensive checksumming
  66  * onto the worker threads.  They checksum file and metadata bios
  67  * just before they are sent down the IO stack.
  68  */
  69 struct async_submit_bio {
  70         struct inode *inode;
  71         struct bio *bio;
  72         struct list_head list;
  73         extent_submit_bio_hook_t *submit_bio_start;
  74         extent_submit_bio_hook_t *submit_bio_done;
  75         int rw;
  76         int mirror_num;
  77         unsigned long bio_flags;
  78         /*
  79          * bio_offset is optional, can be used if the pages in the bio
  80          * can't tell us where in the file the bio should go
  81          */
  82         u64 bio_offset;
  83         struct btrfs_work work;
  84 };
  85
  86 /* These are used to set the lockdep class on the extent buffer locks.
  87  * The class is set by the readpage_end_io_hook after the buffer has
  88  * passed csum validation but before the pages are unlocked.
  89  *
  90  * The lockdep class is also set by btrfs_init_new_buffer on freshly
  91  * allocated blocks.
  92  *
  93  * The class is based on the level in the tree block, which allows lockdep
  94  * to know that lower nodes nest inside the locks of higher nodes.
  95  *
  96  * We also add a check to make sure the highest level of the tree is
  97  * the same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this
  98  * code needs update as well.
  99  */
 100 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 101 # if BTRFS_MAX_LEVEL != 8
 102 #  error
 103 # endif
 104 static struct lock_class_key btrfs_eb_class[BTRFS_MAX_LEVEL + 1];
 105 static const char *btrfs_eb_name[BTRFS_MAX_LEVEL + 1] = {
 106         /* leaf */
 107         "btrfs-extent-00",
 108         "btrfs-extent-01",
 109         "btrfs-extent-02",
 110         "btrfs-extent-03",
 111         "btrfs-extent-04",
 112         "btrfs-extent-05",
 113         "btrfs-extent-06",
 114         "btrfs-extent-07",
 115         /* highest possible level */
 116         "btrfs-extent-08",
 117 };
 118 #endif
 119
 120 /*
 121  * extents on the btree inode are pretty simple, there's one extent
 122  * that covers the entire device
 123  */
 124 static struct extent_map *btree_get_extent(struct inode *inode,
 125                 struct page *page, size_t page_offset, u64 start, u64 len,
 126                 int create)
 127 {
 128         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
 129         struct extent_map *em;
 130         int ret;
 131
 132         read_lock(&em_tree->lock);
 133         em = lookup_extent_mapping(em_tree, start, len);
 134         if (em) {
 135                 em->bdev =
 136                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 137                 read_unlock(&em_tree->lock);
 138                 goto out;
 139         }
 140         read_unlock(&em_tree->lock);
 141
 142         em = alloc_extent_map(GFP_NOFS);
 143         if (!em) {
 144                 em = ERR_PTR(-ENOMEM);
 145                 goto out;
 146         }
 147         em->start = 0;
 148         em->len = (u64)-1;
 149         em->block_len = (u64)-1;
 150         em->block_start = 0;
 151         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 152
 153         write_lock(&em_tree->lock);
 154         ret = add_extent_mapping(em_tree, em);
 155         if (ret == -EEXIST) {
 156                 u64 failed_start = em->start;
 157                 u64 failed_len = em->len;
 158
 159                 free_extent_map(em);
 160                 em = lookup_extent_mapping(em_tree, start, len);
 161                 if (em) {
 162                         ret = 0;
 163                 } else {
 164                         em = lookup_extent_mapping(em_tree, failed_start,
 165                                                    failed_len);
 166                         ret = -EIO;
 167                 }
 168         } else if (ret) {
 169                 free_extent_map(em);
 170                 em = NULL;
 171         }
 172         write_unlock(&em_tree->lock);
 173
 174         if (ret)
 175                 em = ERR_PTR(ret);
 176 out:
 177         return em;
 178 }
 179
 180 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
 181 {
 182         return crc32c(seed, data, len);
 183 }
 184
 185 void btrfs_csum_final(u32 crc, char *result)
 186 {
 187         *(__le32 *)result = ~cpu_to_le32(crc);
 188 }
 189
 190 /*
 191  * compute the csum for a btree block, and either verify it or write it
 192  * into the csum field of the block.
 193  */
 194 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 195                            int verify)
 196 {
 197         u16 csum_size =
 198                 btrfs_super_csum_size(&root->fs_info->super_copy);
 199         char *result = NULL;
 200         unsigned long len;
 201         unsigned long cur_len;
 202         unsigned long offset = BTRFS_CSUM_SIZE;
 203         char *map_token = NULL;
 204         char *kaddr;
 205         unsigned long map_start;
 206         unsigned long map_len;
 207         int err;
 208         u32 crc = ~(u32)0;
 209         unsigned long inline_result;
 210
 211         len = buf->len - offset;
 212         while (len > 0) {
 213                 err = map_private_extent_buffer(buf, offset, 32,
 214                                         &map_token, &kaddr,
 215                                         &map_start, &map_len, KM_USER0);
 216                 if (err)
 217                         return 1;
 218                 cur_len = min(len, map_len - (offset - map_start));
 219                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
 220                                       crc, cur_len);
 221                 len -= cur_len;
 222                 offset += cur_len;
 223                 unmap_extent_buffer(buf, map_token, KM_USER0);
 224         }
 225         if (csum_size > sizeof(inline_result)) {
 226                 result = kzalloc(csum_size * sizeof(char), GFP_NOFS);
 227                 if (!result)
 228                         return 1;
 229         } else {
 230                 result = (char *)&inline_result;
 231         }
 232
 233         btrfs_csum_final(crc, result);
 234
 235         if (verify) {
 236                 if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
 237                         u32 val;
 238                         u32 found = 0;
 239                         memcpy(&found, result, csum_size);
 240
 241                         read_extent_buffer(buf, &val, 0, csum_size);
 242                         if (printk_ratelimit()) {
 243                                 printk(KERN_INFO "btrfs: %s checksum verify "
 244                                        "failed on %llu wanted %X found %X "
 245                                        "level %d\n",
 246                                        root->fs_info->sb->s_id,
 247                                        (unsigned long long)buf->start, val, found,
 248                                        btrfs_header_level(buf));
 249                         }
 250                         if (result != (char *)&inline_result)
 251                                 kfree(result);
 252                         return 1;
 253                 }
 254         } else {
 255                 write_extent_buffer(buf, result, 0, csum_size);
 256         }
 257         if (result != (char *)&inline_result)
 258                 kfree(result);
 259         return 0;
 260 }
 261
 262 /*
 263  * we can't consider a given block up to date unless the transid of the
 264  * block matches the transid in the parent node's pointer.  This is how we
 265  * detect blocks that either didn't get written at all or got written
 266  * in the wrong place.
 267  */
 268 static int verify_parent_transid(struct extent_io_tree *io_tree,
 269                                  struct extent_buffer *eb, u64 parent_transid)
 270 {
 271         struct extent_state *cached_state = NULL;
 272         int ret;
 273
 274         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
 275                 return 0;
 276
 277         lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
 278                          0, &cached_state, GFP_NOFS);
 279         if (extent_buffer_uptodate(io_tree, eb, cached_state) &&
 280             btrfs_header_generation(eb) == parent_transid) {
 281                 ret = 0;
 282                 goto out;
 283         }
 284         if (printk_ratelimit()) {
 285                 printk("parent transid verify failed on %llu wanted %llu "
 286                        "found %llu\n",
 287                        (unsigned long long)eb->start,
 288                        (unsigned long long)parent_transid,
 289                        (unsigned long long)btrfs_header_generation(eb));
 290         }
 291         ret = 1;
 292         clear_extent_buffer_uptodate(io_tree, eb, &cached_state);
 293 out:
 294         unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
 295                              &cached_state, GFP_NOFS);
 296         return ret;
 297 }
 298
 299 /*
 300  * helper to read a given tree block, doing retries as required when
 301  * the checksums don't match and we have alternate mirrors to try.
 302  */
 303 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
 304                                           struct extent_buffer *eb,
 305                                           u64 start, u64 parent_transid)
 306 {
 307         struct extent_io_tree *io_tree;
 308         int ret;
 309         int num_copies = 0;
 310         int mirror_num = 0;
 311
 312         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
 313         while (1) {
 314                 ret = read_extent_buffer_pages(io_tree, eb, start, 1,
 315                                                btree_get_extent, mirror_num);
 316                 if (!ret &&
 317                     !verify_parent_transid(io_tree, eb, parent_transid))
 318                         return ret;
 319
 320                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
 321                                               eb->start, eb->len);
 322                 if (num_copies == 1)
 323                         return ret;
 324
 325                 mirror_num++;
 326                 if (mirror_num > num_copies)
 327                         return ret;
 328         }
 329         return -EIO;
 330 }
 331
 332 /*
 333  * checksum a dirty tree block before IO.  This has extra checks to make sure
 334  * we only fill in the checksum field in the first page of a multi-page block
 335  */
 336
 337 static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 338 {
 339         struct extent_io_tree *tree;
 340         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
 341         u64 found_start;
 342         unsigned long len;
 343         struct extent_buffer *eb;
 344         int ret;
 345
 346         tree = &BTRFS_I(page->mapping->host)->io_tree;
 347
 348         if (page->private == EXTENT_PAGE_PRIVATE)
 349                 goto out;
 350         if (!page->private)
 351                 goto out;
 352         len = page->private >> 2;
 353         WARN_ON(len == 0);
 354
 355         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 356         if (eb == NULL) {
 357                 WARN_ON(1);
 358                 goto out;
 359         }
 360         ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
 361                                              btrfs_header_generation(eb));
 362         BUG_ON(ret);
 363         WARN_ON(!btrfs_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN));
 364
 365         found_start = btrfs_header_bytenr(eb);
 366         if (found_start != start) {
 367                 WARN_ON(1);
 368                 goto err;
 369         }
 370         if (eb->first_page != page) {
 371                 WARN_ON(1);
 372                 goto err;
 373         }
 374         if (!PageUptodate(page)) {
 375                 WARN_ON(1);
 376                 goto err;
 377         }
 378         csum_tree_block(root, eb, 0);
 379 err:
 380         free_extent_buffer(eb);
 381 out:
 382         return 0;
 383 }
 384
 385 static int check_tree_block_fsid(struct btrfs_root *root,
 386                                  struct extent_buffer *eb)
 387 {
 388         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
 389         u8 fsid[BTRFS_UUID_SIZE];
 390         int ret = 1;
 391
 392         read_extent_buffer(eb, fsid, (unsigned long)btrfs_header_fsid(eb),
 393                            BTRFS_FSID_SIZE);
 394         while (fs_devices) {
 395                 if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
 396                         ret = 0;
 397                         break;
 398                 }
 399                 fs_devices = fs_devices->seed;
 400         }
 401         return ret;
 402 }
 403
 404 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 405 void btrfs_set_buffer_lockdep_class(struct extent_buffer *eb, int level)
 406 {
 407         lockdep_set_class_and_name(&eb->lock,
 408                            &btrfs_eb_class[level],
 409                            btrfs_eb_name[level]);
 410 }
 411 #endif
 412
 413 static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 414                                struct extent_state *state)
 415 {
 416         struct extent_io_tree *tree;
 417         u64 found_start;
 418         int found_level;
 419         unsigned long len;
 420         struct extent_buffer *eb;
 421         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 422         int ret = 0;
 423
 424         tree = &BTRFS_I(page->mapping->host)->io_tree;
 425         if (page->private == EXTENT_PAGE_PRIVATE)
 426                 goto out;
 427         if (!page->private)
 428                 goto out;
 429
 430         len = page->private >> 2;
 431         WARN_ON(len == 0);
 432
 433         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 434         if (eb == NULL) {
 435                 ret = -EIO;
 436                 goto out;
 437         }
 438
 439         found_start = btrfs_header_bytenr(eb);
 440         if (found_start != start) {
 441                 if (printk_ratelimit()) {
 442                         printk(KERN_INFO "btrfs bad tree block start "
 443                                "%llu %llu\n",
 444                                (unsigned long long)found_start,
 445                                (unsigned long long)eb->start);
 446                 }
 447                 ret = -EIO;
 448                 goto err;
 449         }
 450         if (eb->first_page != page) {
 451                 printk(KERN_INFO "btrfs bad first page %lu %lu\n",
 452                        eb->first_page->index, page->index);
 453                 WARN_ON(1);
 454                 ret = -EIO;
 455                 goto err;
 456         }
 457         if (check_tree_block_fsid(root, eb)) {
 458                 if (printk_ratelimit()) {
 459                         printk(KERN_INFO "btrfs bad fsid on block %llu\n",
 460                                (unsigned long long)eb->start);
 461                 }
 462                 ret = -EIO;
 463                 goto err;
 464         }
 465         found_level = btrfs_header_level(eb);
 466
 467         btrfs_set_buffer_lockdep_class(eb, found_level);
 468
 469         ret = csum_tree_block(root, eb, 1);
 470         if (ret)
 471                 ret = -EIO;
 472
 473         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
 474         end = eb->start + end - 1;
 475 err:
 476         free_extent_buffer(eb);
 477 out:
 478         return ret;
 479 }
 480
 481 static void end_workqueue_bio(struct bio *bio, int err)
 482 {
 483         struct end_io_wq *end_io_wq = bio->bi_private;
 484         struct btrfs_fs_info *fs_info;
 485
 486         fs_info = end_io_wq->info;
 487         end_io_wq->error = err;
 488         end_io_wq->work.func = end_workqueue_fn;
 489         end_io_wq->work.flags = 0;
 490
 491         if (bio->bi_rw & REQ_WRITE) {
 492                 if (end_io_wq->metadata == 1)
 493                         btrfs_queue_worker(&fs_info->endio_meta_write_workers,
 494                                            &end_io_wq->work);
 495                 else if (end_io_wq->metadata == 2)
 496                         btrfs_queue_worker(&fs_info->endio_freespace_worker,
 497                                            &end_io_wq->work);
 498                 else
 499                         btrfs_queue_worker(&fs_info->endio_write_workers,
 500                                            &end_io_wq->work);
 501         } else {
 502                 if (end_io_wq->metadata)
 503                         btrfs_queue_worker(&fs_info->endio_meta_workers,
 504                                            &end_io_wq->work);
 505                 else
 506                         btrfs_queue_worker(&fs_info->endio_workers,
 507                                            &end_io_wq->work);
 508         }
 509 }
 510
 511 /*
 512  * For the metadata arg you want
 513  *
 514  * 0 - if data
 515  * 1 - if normal metadta
 516  * 2 - if writing to the free space cache area
 517  */
 518 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 519                         int metadata)
 520 {
 521         struct end_io_wq *end_io_wq;
 522         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
 523         if (!end_io_wq)
 524                 return -ENOMEM;
 525
 526         end_io_wq->private = bio->bi_private;
 527         end_io_wq->end_io = bio->bi_end_io;
 528         end_io_wq->info = info;
 529         end_io_wq->error = 0;
 530         end_io_wq->bio = bio;
 531         end_io_wq->metadata = metadata;
 532
 533         bio->bi_private = end_io_wq;
 534         bio->bi_end_io = end_workqueue_bio;
 535         return 0;
 536 }
 537
 538 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
 539 {
 540         unsigned long limit = min_t(unsigned long,
 541                                     info->workers.max_workers,
 542                                     info->fs_devices->open_devices);
 543         return 256 * limit;
 544 }
 545
 546 int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
 547 {
 548         return atomic_read(&info->nr_async_bios) >
 549                 btrfs_async_submit_limit(info);
 550 }
 551
 552 static void run_one_async_start(struct btrfs_work *work)
 553 {
 554         struct async_submit_bio *async;
 555
 556         async = container_of(work, struct  async_submit_bio, work);
 557         async->submit_bio_start(async->inode, async->rw, async->bio,
 558                                async->mirror_num, async->bio_flags,
 559                                async->bio_offset);
 560 }
 561
 562 static void run_one_async_done(struct btrfs_work *work)
 563 {
 564         struct btrfs_fs_info *fs_info;
 565         struct async_submit_bio *async;
 566         int limit;
 567
 568         async = container_of(work, struct  async_submit_bio, work);
 569         fs_info = BTRFS_I(async->inode)->root->fs_info;
 570
 571         limit = btrfs_async_submit_limit(fs_info);
 572         limit = limit * 2 / 3;
 573
 574         atomic_dec(&fs_info->nr_async_submits);
 575
 576         if (atomic_read(&fs_info->nr_async_submits) < limit &&
 577             waitqueue_active(&fs_info->async_submit_wait))
 578                 wake_up(&fs_info->async_submit_wait);
 579
 580         async->submit_bio_done(async->inode, async->rw, async->bio,
 581                                async->mirror_num, async->bio_flags,
 582                                async->bio_offset);
 583 }
 584
 585 static void run_one_async_free(struct btrfs_work *work)
 586 {
 587         struct async_submit_bio *async;
 588
 589         async = container_of(work, struct  async_submit_bio, work);
 590         kfree(async);
 591 }
 592
 593 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
 594                         int rw, struct bio *bio, int mirror_num,
 595                         unsigned long bio_flags,
 596                         u64 bio_offset,
 597                         extent_submit_bio_hook_t *submit_bio_start,
 598                         extent_submit_bio_hook_t *submit_bio_done)
 599 {
 600         struct async_submit_bio *async;
 601
 602         async = kmalloc(sizeof(*async), GFP_NOFS);
 603         if (!async)
 604                 return -ENOMEM;
 605
 606         async->inode = inode;
 607         async->rw = rw;
 608         async->bio = bio;
 609         async->mirror_num = mirror_num;
 610         async->submit_bio_start = submit_bio_start;
 611         async->submit_bio_done = submit_bio_done;
 612
 613         async->work.func = run_one_async_start;
 614         async->work.ordered_func = run_one_async_done;
 615         async->work.ordered_free = run_one_async_free;
 616
 617         async->work.flags = 0;
 618         async->bio_flags = bio_flags;
 619         async->bio_offset = bio_offset;
 620
 621         atomic_inc(&fs_info->nr_async_submits);
 622
 623         if (rw & REQ_SYNC)
 624                 btrfs_set_work_high_prio(&async->work);
 625
 626         btrfs_queue_worker(&fs_info->workers, &async->work);
 627
 628         while (atomic_read(&fs_info->async_submit_draining) &&
 629               atomic_read(&fs_info->nr_async_submits)) {
 630                 wait_event(fs_info->async_submit_wait,
 631                            (atomic_read(&fs_info->nr_async_submits) == 0));
 632         }
 633
 634         return 0;
 635 }
 636
 637 static int btree_csum_one_bio(struct bio *bio)
 638 {
 639         struct bio_vec *bvec = bio->bi_io_vec;
 640         int bio_index = 0;
 641         struct btrfs_root *root;
 642
 643         WARN_ON(bio->bi_vcnt <= 0);
 644         while (bio_index < bio->bi_vcnt) {
 645                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
 646                 csum_dirty_buffer(root, bvec->bv_page);
 647                 bio_index++;
 648                 bvec++;
 649         }
 650         return 0;
 651 }
 652
 653 static int __btree_submit_bio_start(struct inode *inode, int rw,
 654                                     struct bio *bio, int mirror_num,
 655                                     unsigned long bio_flags,
 656                                     u64 bio_offset)
 657 {
 658         /*
 659          * when we're called for a write, we're already in the async
 660          * submission context.  Just jump into btrfs_map_bio
 661          */
 662         btree_csum_one_bio(bio);
 663         return 0;
 664 }
 665
 666 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
 667                                  int mirror_num, unsigned long bio_flags,
 668                                  u64 bio_offset)
 669 {
 670         /*
 671          * when we're called for a write, we're already in the async
 672          * submission context.  Just jump into btrfs_map_bio
 673          */
 674         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
 675 }
 676
 677 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 678                                  int mirror_num, unsigned long bio_flags,
 679                                  u64 bio_offset)
 680 {
 681         int ret;
 682
 683         ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
 684                                           bio, 1);
 685         BUG_ON(ret);
 686
 687         if (!(rw & REQ_WRITE)) {
 688                 /*
 689                  * called for a read, do the setup so that checksum validation
 690                  * can happen in the async kernel threads
 691                  */
 692                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
 693                                      mirror_num, 0);
 694         }
 695
 696         /*
 697          * kthread helpers are used to submit writes so that checksumming
 698          * can happen in parallel across all CPUs
 699          */
 700         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
 701                                    inode, rw, bio, mirror_num, 0,
 702                                    bio_offset,
 703                                    __btree_submit_bio_start,
 704                                    __btree_submit_bio_done);
 705 }
 706
 707 #ifdef CONFIG_MIGRATION
 708 static int btree_migratepage(struct address_space *mapping,
 709                         struct page *newpage, struct page *page)
 710 {
 711         /*
 712          * we can't safely write a btree page from here,
 713          * we haven't done the locking hook
 714          */
 715         if (PageDirty(page))
 716                 return -EAGAIN;
 717         /*
 718          * Buffers may be managed in a filesystem specific way.
 719          * We must have no buffers or drop them.
 720          */
 721         if (page_has_private(page) &&
 722             !try_to_release_page(page, GFP_KERNEL))
 723                 return -EAGAIN;
 724         return migrate_page(mapping, newpage, page);
 725 }
 726 #endif
 727
 728 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 729 {
 730         struct extent_io_tree *tree;
 731         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 732         struct extent_buffer *eb;
 733         int was_dirty;
 734
 735         tree = &BTRFS_I(page->mapping->host)->io_tree;
 736         if (!(current->flags & PF_MEMALLOC)) {
 737                 return extent_write_full_page(tree, page,
 738                                               btree_get_extent, wbc);
 739         }
 740
 741         redirty_page_for_writepage(wbc, page);
 742         eb = btrfs_find_tree_block(root, page_offset(page), PAGE_CACHE_SIZE);
 743         WARN_ON(!eb);
 744
 745         was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
 746         if (!was_dirty) {
 747                 spin_lock(&root->fs_info->delalloc_lock);
 748                 root->fs_info->dirty_metadata_bytes += PAGE_CACHE_SIZE;
 749                 spin_unlock(&root->fs_info->delalloc_lock);
 750         }
 751         free_extent_buffer(eb);
 752
 753         unlock_page(page);
 754         return 0;
 755 }
 756
 757 static int btree_writepages(struct address_space *mapping,
 758                             struct writeback_control *wbc)
 759 {
 760         struct extent_io_tree *tree;
 761         tree = &BTRFS_I(mapping->host)->io_tree;
 762         if (wbc->sync_mode == WB_SYNC_NONE) {
 763                 struct btrfs_root *root = BTRFS_I(mapping->host)->root;
 764                 u64 num_dirty;
 765                 unsigned long thresh = 32 * 1024 * 1024;
 766
 767                 if (wbc->for_kupdate)
 768                         return 0;
 769
 770                 /* this is a bit racy, but that's ok */
 771                 num_dirty = root->fs_info->dirty_metadata_bytes;
 772                 if (num_dirty < thresh)
 773                         return 0;
 774         }
 775         return extent_writepages(tree, mapping, btree_get_extent, wbc);
 776 }
 777
 778 static int btree_readpage(struct file *file, struct page *page)
 779 {
 780         struct extent_io_tree *tree;
 781         tree = &BTRFS_I(page->mapping->host)->io_tree;
 782         return extent_read_full_page(tree, page, btree_get_extent);
 783 }
 784
 785 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 786 {
 787         struct extent_io_tree *tree;
 788         struct extent_map_tree *map;
 789         int ret;
 790
 791         if (PageWriteback(page) || PageDirty(page))
 792                 return 0;
 793
 794         tree = &BTRFS_I(page->mapping->host)->io_tree;
 795         map = &BTRFS_I(page->mapping->host)->extent_tree;
 796
 797         ret = try_release_extent_state(map, tree, page, gfp_flags);
 798         if (!ret)
 799                 return 0;
 800
 801         ret = try_release_extent_buffer(tree, page);
 802         if (ret == 1) {
 803                 ClearPagePrivate(page);
 804                 set_page_private(page, 0);
 805                 page_cache_release(page);
 806         }
 807
 808         return ret;
 809 }
 810
 811 static void btree_invalidatepage(struct page *page, unsigned long offset)
 812 {
 813         struct extent_io_tree *tree;
 814         tree = &BTRFS_I(page->mapping->host)->io_tree;
 815         extent_invalidatepage(tree, page, offset);
 816         btree_releasepage(page, GFP_NOFS);
 817         if (PagePrivate(page)) {
 818                 printk(KERN_WARNING "btrfs warning page private not zero "
 819                        "on page %llu\n", (unsigned long long)page_offset(page));
 820                 ClearPagePrivate(page);
 821                 set_page_private(page, 0);
 822                 page_cache_release(page);
 823         }
 824 }
 825
 826 static const struct address_space_operations btree_aops = {
 827         .readpage       = btree_readpage,
 828         .writepage      = btree_writepage,
 829         .writepages     = btree_writepages,
 830         .releasepage    = btree_releasepage,
 831         .invalidatepage = btree_invalidatepage,
 832         .sync_page      = block_sync_page,
 833 #ifdef CONFIG_MIGRATION
 834         .migratepage    = btree_migratepage,
 835 #endif
 836 };
 837
 838 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
 839                          u64 parent_transid)
 840 {
 841         struct extent_buffer *buf = NULL;
 842         struct inode *btree_inode = root->fs_info->btree_inode;
 843         int ret = 0;
 844
 845         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 846         if (!buf)
 847                 return 0;
 848         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
 849                                  buf, 0, 0, btree_get_extent, 0);
 850         free_extent_buffer(buf);
 851         return ret;
 852 }
 853
 854 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
 855                                             u64 bytenr, u32 blocksize)
 856 {
 857         struct inode *btree_inode = root->fs_info->btree_inode;
 858         struct extent_buffer *eb;
 859         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 860                                 bytenr, blocksize, GFP_NOFS);
 861         return eb;
 862 }
 863
 864 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 865                                                  u64 bytenr, u32 blocksize)
 866 {
 867         struct inode *btree_inode = root->fs_info->btree_inode;
 868         struct extent_buffer *eb;
 869
 870         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 871                                  bytenr, blocksize, NULL, GFP_NOFS);
 872         return eb;
 873 }
 874
 875
 876 int btrfs_write_tree_block(struct extent_buffer *buf)
 877 {
 878         return filemap_fdatawrite_range(buf->first_page->mapping, buf->start,
 879                                         buf->start + buf->len - 1);
 880 }
 881
 882 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
 883 {
 884         return filemap_fdatawait_range(buf->first_page->mapping,
 885                                        buf->start, buf->start + buf->len - 1);
 886 }
 887
 888 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 889                                       u32 blocksize, u64 parent_transid)
 890 {
 891         struct extent_buffer *buf = NULL;
 892         int ret;
 893
 894         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 895         if (!buf)
 896                 return NULL;
 897
 898         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
 899
 900         if (ret == 0)
 901                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
 902         return buf;
 903
 904 }
 905
 906 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 907                      struct extent_buffer *buf)
 908 {
 909         struct inode *btree_inode = root->fs_info->btree_inode;
 910         if (btrfs_header_generation(buf) ==
 911             root->fs_info->running_transaction->transid) {
 912                 btrfs_assert_tree_locked(buf);
 913
 914                 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
 915                         spin_lock(&root->fs_info->delalloc_lock);
 916                         if (root->fs_info->dirty_metadata_bytes >= buf->len)
 917                                 root->fs_info->dirty_metadata_bytes -= buf->len;
 918                         else
 919                                 WARN_ON(1);
 920                         spin_unlock(&root->fs_info->delalloc_lock);
 921                 }
 922
 923                 /* ugh, clear_extent_buffer_dirty needs to lock the page */
 924                 btrfs_set_lock_blocking(buf);
 925                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
 926                                           buf);
 927         }
 928         return 0;
 929 }
 930
 931 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 932                         u32 stripesize, struct btrfs_root *root,
 933                         struct btrfs_fs_info *fs_info,
 934                         u64 objectid)
 935 {
 936         root->node = NULL;
 937         root->commit_root = NULL;
 938         root->sectorsize = sectorsize;
 939         root->nodesize = nodesize;
 940         root->leafsize = leafsize;
 941         root->stripesize = stripesize;
 942         root->ref_cows = 0;
 943         root->track_dirty = 0;
 944         root->in_radix = 0;
 945         root->orphan_item_inserted = 0;
 946         root->orphan_cleanup_state = 0;
 947
 948         root->fs_info = fs_info;
 949         root->objectid = objectid;
 950         root->last_trans = 0;
 951         root->highest_objectid = 0;
 952         root->name = NULL;
 953         root->in_sysfs = 0;
 954         root->inode_tree = RB_ROOT;
 955         root->block_rsv = NULL;
 956         root->orphan_block_rsv = NULL;
 957
 958         INIT_LIST_HEAD(&root->dirty_list);
 959         INIT_LIST_HEAD(&root->orphan_list);
 960         INIT_LIST_HEAD(&root->root_list);
 961         spin_lock_init(&root->node_lock);
 962         spin_lock_init(&root->orphan_lock);
 963         spin_lock_init(&root->inode_lock);
 964         spin_lock_init(&root->accounting_lock);
 965         mutex_init(&root->objectid_mutex);
 966         mutex_init(&root->log_mutex);
 967         init_waitqueue_head(&root->log_writer_wait);
 968         init_waitqueue_head(&root->log_commit_wait[0]);
 969         init_waitqueue_head(&root->log_commit_wait[1]);
 970         atomic_set(&root->log_commit[0], 0);
 971         atomic_set(&root->log_commit[1], 0);
 972         atomic_set(&root->log_writers, 0);
 973         root->log_batch = 0;
 974         root->log_transid = 0;
 975         root->last_log_commit = 0;
 976         extent_io_tree_init(&root->dirty_log_pages,
 977                              fs_info->btree_inode->i_mapping, GFP_NOFS);
 978
 979         memset(&root->root_key, 0, sizeof(root->root_key));
 980         memset(&root->root_item, 0, sizeof(root->root_item));
 981         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
 982         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
 983         root->defrag_trans_start = fs_info->generation;
 984         init_completion(&root->kobj_unregister);
 985         root->defrag_running = 0;
 986         root->root_key.objectid = objectid;
 987         root->anon_super.s_root = NULL;
 988         root->anon_super.s_dev = 0;
 989         INIT_LIST_HEAD(&root->anon_super.s_list);
 990         INIT_LIST_HEAD(&root->anon_super.s_instances);
 991         init_rwsem(&root->anon_super.s_umount);
 992
 993         return 0;
 994 }
 995
 996 static int find_and_setup_root(struct btrfs_root *tree_root,
 997                                struct btrfs_fs_info *fs_info,
 998                                u64 objectid,
 999                                struct btrfs_root *root)
1000 {
1001         int ret;
1002         u32 blocksize;
1003         u64 generation;
1004
1005         __setup_root(tree_root->nodesize, tree_root->leafsize,
1006                      tree_root->sectorsize, tree_root->stripesize,
1007                      root, fs_info, objectid);
1008         ret = btrfs_find_last_root(tree_root, objectid,
1009                                    &root->root_item, &root->root_key);
1010         if (ret > 0)
1011                 return -ENOENT;
1012         BUG_ON(ret);
1013
1014         generation = btrfs_root_generation(&root->root_item);
1015         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1016         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1017                                      blocksize, generation);
1018         if (!root->node || !btrfs_buffer_uptodate(root->node, generation)) {
1019                 free_extent_buffer(root->node);
1020                 return -EIO;
1021         }
1022         root->commit_root = btrfs_root_node(root);
1023         return 0;
1024 }
1025
1026 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1027                                          struct btrfs_fs_info *fs_info)
1028 {
1029         struct btrfs_root *root;
1030         struct btrfs_root *tree_root = fs_info->tree_root;
1031         struct extent_buffer *leaf;
1032
1033         root = kzalloc(sizeof(*root), GFP_NOFS);
1034         if (!root)
1035                 return ERR_PTR(-ENOMEM);
1036
1037         __setup_root(tree_root->nodesize, tree_root->leafsize,
1038                      tree_root->sectorsize, tree_root->stripesize,
1039                      root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1040
1041         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1042         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1043         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1044         /*
1045          * log trees do not get reference counted because they go away
1046          * before a real commit is actually done.  They do store pointers
1047          * to file data extents, and those reference counts still get
1048          * updated (along with back refs to the log tree).
1049          */
1050         root->ref_cows = 0;
1051
1052         leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
1053                                       BTRFS_TREE_LOG_OBJECTID, NULL, 0, 0, 0);
1054         if (IS_ERR(leaf)) {
1055                 kfree(root);
1056                 return ERR_CAST(leaf);
1057         }
1058
1059         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1060         btrfs_set_header_bytenr(leaf, leaf->start);
1061         btrfs_set_header_generation(leaf, trans->transid);
1062         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1063         btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1064         root->node = leaf;
1065
1066         write_extent_buffer(root->node, root->fs_info->fsid,
1067                             (unsigned long)btrfs_header_fsid(root->node),
1068                             BTRFS_FSID_SIZE);
1069         btrfs_mark_buffer_dirty(root->node);
1070         btrfs_tree_unlock(root->node);
1071         return root;
1072 }
1073
1074 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1075                              struct btrfs_fs_info *fs_info)
1076 {
1077         struct btrfs_root *log_root;
1078
1079         log_root = alloc_log_tree(trans, fs_info);
1080         if (IS_ERR(log_root))
1081                 return PTR_ERR(log_root);
1082         WARN_ON(fs_info->log_root_tree);
1083         fs_info->log_root_tree = log_root;
1084         return 0;
1085 }
1086
1087 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1088                        struct btrfs_root *root)
1089 {
1090         struct btrfs_root *log_root;
1091         struct btrfs_inode_item *inode_item;
1092
1093         log_root = alloc_log_tree(trans, root->fs_info);
1094         if (IS_ERR(log_root))
1095                 return PTR_ERR(log_root);
1096
1097         log_root->last_trans = trans->transid;
1098         log_root->root_key.offset = root->root_key.objectid;
1099
1100         inode_item = &log_root->root_item.inode;
1101         inode_item->generation = cpu_to_le64(1);
1102         inode_item->size = cpu_to_le64(3);
1103         inode_item->nlink = cpu_to_le32(1);
1104         inode_item->nbytes = cpu_to_le64(root->leafsize);
1105         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
1106
1107         btrfs_set_root_node(&log_root->root_item, log_root->node);
1108
1109         WARN_ON(root->log_root);
1110         root->log_root = log_root;
1111         root->log_transid = 0;
1112         root->last_log_commit = 0;
1113         return 0;
1114 }
1115
1116 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
1117                                                struct btrfs_key *location)
1118 {
1119         struct btrfs_root *root;
1120         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1121         struct btrfs_path *path;
1122         struct extent_buffer *l;
1123         u64 generation;
1124         u32 blocksize;
1125         int ret = 0;
1126
1127         root = kzalloc(sizeof(*root), GFP_NOFS);
1128         if (!root)
1129                 return ERR_PTR(-ENOMEM);
1130         if (location->offset == (u64)-1) {
1131                 ret = find_and_setup_root(tree_root, fs_info,
1132                                           location->objectid, root);
1133                 if (ret) {
1134                         kfree(root);
1135                         return ERR_PTR(ret);
1136                 }
1137                 goto out;
1138         }
1139
1140         __setup_root(tree_root->nodesize, tree_root->leafsize,
1141                      tree_root->sectorsize, tree_root->stripesize,
1142                      root, fs_info, location->objectid);
1143
1144         path = btrfs_alloc_path();
1145         BUG_ON(!path);
1146         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
1147         if (ret == 0) {
1148                 l = path->nodes[0];
1149                 read_extent_buffer(l, &root->root_item,
1150                                 btrfs_item_ptr_offset(l, path->slots[0]),
1151                                 sizeof(root->root_item));
1152                 memcpy(&root->root_key, location, sizeof(*location));
1153         }
1154         btrfs_free_path(path);
1155         if (ret) {
1156                 if (ret > 0)
1157                         ret = -ENOENT;
1158                 return ERR_PTR(ret);
1159         }
1160
1161         generation = btrfs_root_generation(&root->root_item);
1162         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1163         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1164                                      blocksize, generation);
1165         root->commit_root = btrfs_root_node(root);
1166         BUG_ON(!root->node);
1167 out:
1168         if (location->objectid != BTRFS_TREE_LOG_OBJECTID)
1169                 root->ref_cows = 1;
1170
1171         return root;
1172 }
1173
1174 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1175                                         u64 root_objectid)
1176 {
1177         struct btrfs_root *root;
1178
1179         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
1180                 return fs_info->tree_root;
1181         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
1182                 return fs_info->extent_root;
1183
1184         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1185                                  (unsigned long)root_objectid);
1186         return root;
1187 }
1188
1189 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
1190                                               struct btrfs_key *location)
1191 {
1192         struct btrfs_root *root;
1193         int ret;
1194
1195         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1196                 return fs_info->tree_root;
1197         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1198                 return fs_info->extent_root;
1199         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1200                 return fs_info->chunk_root;
1201         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1202                 return fs_info->dev_root;
1203         if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1204                 return fs_info->csum_root;
1205 again:
1206         spin_lock(&fs_info->fs_roots_radix_lock);
1207         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1208                                  (unsigned long)location->objectid);
1209         spin_unlock(&fs_info->fs_roots_radix_lock);
1210         if (root)
1211                 return root;
1212
1213         root = btrfs_read_fs_root_no_radix(fs_info->tree_root, location);
1214         if (IS_ERR(root))
1215                 return root;
1216
1217         set_anon_super(&root->anon_super, NULL);
1218
1219         if (btrfs_root_refs(&root->root_item) == 0) {
1220                 ret = -ENOENT;
1221                 goto fail;
1222         }
1223
1224         ret = btrfs_find_orphan_item(fs_info->tree_root, location->objectid);
1225         if (ret < 0)
1226                 goto fail;
1227         if (ret == 0)
1228                 root->orphan_item_inserted = 1;
1229
1230         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1231         if (ret)
1232                 goto fail;
1233
1234         spin_lock(&fs_info->fs_roots_radix_lock);
1235         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1236                                 (unsigned long)root->root_key.objectid,
1237                                 root);
1238         if (ret == 0)
1239                 root->in_radix = 1;
1240
1241         spin_unlock(&fs_info->fs_roots_radix_lock);
1242         radix_tree_preload_end();
1243         if (ret) {
1244                 if (ret == -EEXIST) {
1245                         free_fs_root(root);
1246                         goto again;
1247                 }
1248                 goto fail;
1249         }
1250
1251         ret = btrfs_find_dead_roots(fs_info->tree_root,
1252                                     root->root_key.objectid);
1253         WARN_ON(ret);
1254         return root;
1255 fail:
1256         free_fs_root(root);
1257         return ERR_PTR(ret);
1258 }
1259
1260 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
1261                                       struct btrfs_key *location,
1262                                       const char *name, int namelen)
1263 {
1264         return btrfs_read_fs_root_no_name(fs_info, location);
1265 #if 0
1266         struct btrfs_root *root;
1267         int ret;
1268
1269         root = btrfs_read_fs_root_no_name(fs_info, location);
1270         if (!root)
1271                 return NULL;
1272
1273         if (root->in_sysfs)
1274                 return root;
1275
1276         ret = btrfs_set_root_name(root, name, namelen);
1277         if (ret) {
1278                 free_extent_buffer(root->node);
1279                 kfree(root);
1280                 return ERR_PTR(ret);
1281         }
1282
1283         ret = btrfs_sysfs_add_root(root);
1284         if (ret) {
1285                 free_extent_buffer(root->node);
1286                 kfree(root->name);
1287                 kfree(root);
1288                 return ERR_PTR(ret);
1289         }
1290         root->in_sysfs = 1;
1291         return root;
1292 #endif
1293 }
1294
1295 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1296 {
1297         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1298         int ret = 0;
1299         struct btrfs_device *device;
1300         struct backing_dev_info *bdi;
1301
1302         list_for_each_entry(device, &info->fs_devices->devices, dev_list) {
1303                 if (!device->bdev)
1304                         continue;
1305                 bdi = blk_get_backing_dev_info(device->bdev);
1306                 if (bdi && bdi_congested(bdi, bdi_bits)) {
1307                         ret = 1;
1308                         break;
1309                 }
1310         }
1311         return ret;
1312 }
1313
1314 /*
1315  * this unplugs every device on the box, and it is only used when page
1316  * is null
1317  */
1318 static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1319 {
1320         struct btrfs_device *device;
1321         struct btrfs_fs_info *info;
1322
1323         info = (struct btrfs_fs_info *)bdi->unplug_io_data;
1324         list_for_each_entry(device, &info->fs_devices->devices, dev_list) {
1325                 if (!device->bdev)
1326                         continue;
1327
1328                 bdi = blk_get_backing_dev_info(device->bdev);
1329                 if (bdi->unplug_io_fn)
1330                         bdi->unplug_io_fn(bdi, page);
1331         }
1332 }
1333
1334 static void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1335 {
1336         struct inode *inode;
1337         struct extent_map_tree *em_tree;
1338         struct extent_map *em;
1339         struct address_space *mapping;
1340         u64 offset;
1341
1342         /* the generic O_DIRECT read code does this */
1343         if (1 || !page) {
1344                 __unplug_io_fn(bdi, page);
1345                 return;
1346         }
1347
1348         /*
1349          * page->mapping may change at any time.  Get a consistent copy
1350          * and use that for everything below
1351          */
1352         smp_mb();
1353         mapping = page->mapping;
1354         if (!mapping)
1355                 return;
1356
1357         inode = mapping->host;
1358
1359         /*
1360          * don't do the expensive searching for a small number of
1361          * devices
1362          */
1363         if (BTRFS_I(inode)->root->fs_info->fs_devices->open_devices <= 2) {
1364                 __unplug_io_fn(bdi, page);
1365                 return;
1366         }
1367
1368         offset = page_offset(page);
1369
1370         em_tree = &BTRFS_I(inode)->extent_tree;
1371         read_lock(&em_tree->lock);
1372         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
1373         read_unlock(&em_tree->lock);
1374         if (!em) {
1375                 __unplug_io_fn(bdi, page);
1376                 return;
1377         }
1378
1379         if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1380                 free_extent_map(em);
1381                 __unplug_io_fn(bdi, page);
1382                 return;
1383         }
1384         offset = offset - em->start;
1385         btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
1386                           em->block_start + offset, page);
1387         free_extent_map(em);
1388 }
1389
1390 /*
1391  * If this fails, caller must call bdi_destroy() to get rid of the
1392  * bdi again.
1393  */
1394 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1395 {
1396         int err;
1397
1398         bdi->capabilities = BDI_CAP_MAP_COPY;
1399         err = bdi_setup_and_register(bdi, "btrfs", BDI_CAP_MAP_COPY);
1400         if (err)
1401                 return err;
1402
1403         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1404         bdi->unplug_io_fn       = btrfs_unplug_io_fn;
1405         bdi->unplug_io_data     = info;
1406         bdi->congested_fn       = btrfs_congested_fn;
1407         bdi->congested_data     = info;
1408         return 0;
1409 }
1410
1411 static int bio_ready_for_csum(struct bio *bio)
1412 {
1413         u64 length = 0;
1414         u64 buf_len = 0;
1415         u64 start = 0;
1416         struct page *page;
1417         struct extent_io_tree *io_tree = NULL;
1418         struct bio_vec *bvec;
1419         int i;
1420         int ret;
1421
1422         bio_for_each_segment(bvec, bio, i) {
1423                 page = bvec->bv_page;
1424                 if (page->private == EXTENT_PAGE_PRIVATE) {
1425                         length += bvec->bv_len;
1426                         continue;
1427                 }
1428                 if (!page->private) {
1429                         length += bvec->bv_len;
1430                         continue;
1431                 }
1432                 length = bvec->bv_len;
1433                 buf_len = page->private >> 2;
1434                 start = page_offset(page) + bvec->bv_offset;
1435                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1436         }
1437         /* are we fully contained in this bio? */
1438         if (buf_len <= length)
1439                 return 1;
1440
1441         ret = extent_range_uptodate(io_tree, start + length,
1442                                     start + buf_len - 1);
1443         return ret;
1444 }
1445
1446 /*
1447  * called by the kthread helper functions to finally call the bio end_io
1448  * functions.  This is where read checksum verification actually happens
1449  */
1450 static void end_workqueue_fn(struct btrfs_work *work)
1451 {
1452         struct bio *bio;
1453         struct end_io_wq *end_io_wq;
1454         struct btrfs_fs_info *fs_info;
1455         int error;
1456
1457         end_io_wq = container_of(work, struct end_io_wq, work);
1458         bio = end_io_wq->bio;
1459         fs_info = end_io_wq->info;
1460
1461         /* metadata bio reads are special because the whole tree block must
1462          * be checksummed at once.  This makes sure the entire block is in
1463          * ram and up to date before trying to verify things.  For
1464          * blocksize <= pagesize, it is basically a noop
1465          */
1466         if (!(bio->bi_rw & REQ_WRITE) && end_io_wq->metadata &&
1467             !bio_ready_for_csum(bio)) {
1468                 btrfs_queue_worker(&fs_info->endio_meta_workers,
1469                                    &end_io_wq->work);
1470                 return;
1471         }
1472         error = end_io_wq->error;
1473         bio->bi_private = end_io_wq->private;
1474         bio->bi_end_io = end_io_wq->end_io;
1475         kfree(end_io_wq);
1476         bio_endio(bio, error);
1477 }
1478
1479 static int cleaner_kthread(void *arg)
1480 {
1481         struct btrfs_root *root = arg;
1482
1483         do {
1484                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1485
1486                 if (!(root->fs_info->sb->s_flags & MS_RDONLY) &&
1487                     mutex_trylock(&root->fs_info->cleaner_mutex)) {
1488                         btrfs_run_delayed_iputs(root);
1489                         btrfs_clean_old_snapshots(root);
1490                         mutex_unlock(&root->fs_info->cleaner_mutex);
1491                 }
1492
1493                 if (freezing(current)) {
1494                         refrigerator();
1495                 } else {
1496                         set_current_state(TASK_INTERRUPTIBLE);
1497                         if (!kthread_should_stop())
1498                                 schedule();
1499                         __set_current_state(TASK_RUNNING);
1500                 }
1501         } while (!kthread_should_stop());
1502         return 0;
1503 }
1504
1505 static int transaction_kthread(void *arg)
1506 {
1507         struct btrfs_root *root = arg;
1508         struct btrfs_trans_handle *trans;
1509         struct btrfs_transaction *cur;
1510         u64 transid;
1511         unsigned long now;
1512         unsigned long delay;
1513         int ret;
1514
1515         do {
1516                 delay = HZ * 30;
1517                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1518                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1519
1520                 spin_lock(&root->fs_info->new_trans_lock);
1521                 cur = root->fs_info->running_transaction;
1522                 if (!cur) {
1523                         spin_unlock(&root->fs_info->new_trans_lock);
1524                         goto sleep;
1525                 }
1526
1527                 now = get_seconds();
1528                 if (!cur->blocked &&
1529                     (now < cur->start_time || now - cur->start_time < 30)) {
1530                         spin_unlock(&root->fs_info->new_trans_lock);
1531                         delay = HZ * 5;
1532                         goto sleep;
1533                 }
1534                 transid = cur->transid;
1535                 spin_unlock(&root->fs_info->new_trans_lock);
1536
1537                 trans = btrfs_join_transaction(root, 1);
1538                 if (transid == trans->transid) {
1539                         ret = btrfs_commit_transaction(trans, root);
1540                         BUG_ON(ret);
1541                 } else {
1542                         btrfs_end_transaction(trans, root);
1543                 }
1544 sleep:
1545                 wake_up_process(root->fs_info->cleaner_kthread);
1546                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1547
1548                 if (freezing(current)) {
1549                         refrigerator();
1550                 } else {
1551                         set_current_state(TASK_INTERRUPTIBLE);
1552                         if (!kthread_should_stop() &&
1553                             !btrfs_transaction_blocked(root->fs_info))
1554                                 schedule_timeout(delay);
1555                         __set_current_state(TASK_RUNNING);
1556                 }
1557         } while (!kthread_should_stop());
1558         return 0;
1559 }
1560
1561 struct btrfs_root *open_ctree(struct super_block *sb,
1562                               struct btrfs_fs_devices *fs_devices,
1563                               char *options)
1564 {
1565         u32 sectorsize;
1566         u32 nodesize;
1567         u32 leafsize;
1568         u32 blocksize;
1569         u32 stripesize;
1570         u64 generation;
1571         u64 features;
1572         struct btrfs_key location;
1573         struct buffer_head *bh;
1574         struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
1575                                                  GFP_NOFS);
1576         struct btrfs_root *csum_root = kzalloc(sizeof(struct btrfs_root),
1577                                                  GFP_NOFS);
1578         struct btrfs_root *tree_root = btrfs_sb(sb);
1579         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1580         struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
1581                                                 GFP_NOFS);
1582         struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
1583                                               GFP_NOFS);
1584         struct btrfs_root *log_tree_root;
1585
1586         int ret;
1587         int err = -EINVAL;
1588
1589         struct btrfs_super_block *disk_super;
1590
1591         if (!extent_root || !tree_root || !fs_info ||
1592             !chunk_root || !dev_root || !csum_root) {
1593                 err = -ENOMEM;
1594                 goto fail;
1595         }
1596
1597         ret = init_srcu_struct(&fs_info->subvol_srcu);
1598         if (ret) {
1599                 err = ret;
1600                 goto fail;
1601         }
1602
1603         ret = setup_bdi(fs_info, &fs_info->bdi);
1604         if (ret) {
1605                 err = ret;
1606                 goto fail_srcu;
1607         }
1608
1609         fs_info->btree_inode = new_inode(sb);
1610         if (!fs_info->btree_inode) {
1611                 err = -ENOMEM;
1612                 goto fail_bdi;
1613         }
1614
1615         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
1616         INIT_LIST_HEAD(&fs_info->trans_list);
1617         INIT_LIST_HEAD(&fs_info->dead_roots);
1618         INIT_LIST_HEAD(&fs_info->delayed_iputs);
1619         INIT_LIST_HEAD(&fs_info->hashers);
1620         INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1621         INIT_LIST_HEAD(&fs_info->ordered_operations);
1622         INIT_LIST_HEAD(&fs_info->caching_block_groups);
1623         spin_lock_init(&fs_info->delalloc_lock);
1624         spin_lock_init(&fs_info->new_trans_lock);
1625         spin_lock_init(&fs_info->ref_cache_lock);
1626         spin_lock_init(&fs_info->fs_roots_radix_lock);
1627         spin_lock_init(&fs_info->delayed_iput_lock);
1628
1629         init_completion(&fs_info->kobj_unregister);
1630         fs_info->tree_root = tree_root;
1631         fs_info->extent_root = extent_root;
1632         fs_info->csum_root = csum_root;
1633         fs_info->chunk_root = chunk_root;
1634         fs_info->dev_root = dev_root;
1635         fs_info->fs_devices = fs_devices;
1636         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1637         INIT_LIST_HEAD(&fs_info->space_info);
1638         btrfs_mapping_init(&fs_info->mapping_tree);
1639         btrfs_init_block_rsv(&fs_info->global_block_rsv);
1640         btrfs_init_block_rsv(&fs_info->delalloc_block_rsv);
1641         btrfs_init_block_rsv(&fs_info->trans_block_rsv);
1642         btrfs_init_block_rsv(&fs_info->chunk_block_rsv);
1643         btrfs_init_block_rsv(&fs_info->empty_block_rsv);
1644         INIT_LIST_HEAD(&fs_info->durable_block_rsv_list);
1645         mutex_init(&fs_info->durable_block_rsv_mutex);
1646         atomic_set(&fs_info->nr_async_submits, 0);
1647         atomic_set(&fs_info->async_delalloc_pages, 0);
1648         atomic_set(&fs_info->async_submit_draining, 0);
1649         atomic_set(&fs_info->nr_async_bios, 0);
1650         fs_info->sb = sb;
1651         fs_info->max_inline = 8192 * 1024;
1652         fs_info->metadata_ratio = 0;
1653
1654         fs_info->thread_pool_size = min_t(unsigned long,
1655                                           num_online_cpus() + 2, 8);
1656
1657         INIT_LIST_HEAD(&fs_info->ordered_extents);
1658         spin_lock_init(&fs_info->ordered_extent_lock);
1659
1660         sb->s_blocksize = 4096;
1661         sb->s_blocksize_bits = blksize_bits(4096);
1662         sb->s_bdi = &fs_info->bdi;
1663
1664         fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
1665         fs_info->btree_inode->i_nlink = 1;
1666         /*
1667          * we set the i_size on the btree inode to the max possible int.
1668          * the real end of the address space is determined by all of
1669          * the devices in the system
1670          */
1671         fs_info->btree_inode->i_size = OFFSET_MAX;
1672         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1673         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1674
1675         RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
1676         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1677                              fs_info->btree_inode->i_mapping,
1678                              GFP_NOFS);
1679         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1680                              GFP_NOFS);
1681
1682         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1683
1684         BTRFS_I(fs_info->btree_inode)->root = tree_root;
1685         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1686                sizeof(struct btrfs_key));
1687         BTRFS_I(fs_info->btree_inode)->dummy_inode = 1;
1688         insert_inode_hash(fs_info->btree_inode);
1689
1690         spin_lock_init(&fs_info->block_group_cache_lock);
1691         fs_info->block_group_cache_tree = RB_ROOT;
1692
1693         extent_io_tree_init(&fs_info->freed_extents[0],
1694                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1695         extent_io_tree_init(&fs_info->freed_extents[1],
1696                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1697         fs_info->pinned_extents = &fs_info->freed_extents[0];
1698         fs_info->do_barriers = 1;
1699
1700
1701         mutex_init(&fs_info->trans_mutex);
1702         mutex_init(&fs_info->ordered_operations_mutex);
1703         mutex_init(&fs_info->tree_log_mutex);
1704         mutex_init(&fs_info->chunk_mutex);
1705         mutex_init(&fs_info->transaction_kthread_mutex);
1706         mutex_init(&fs_info->cleaner_mutex);
1707         mutex_init(&fs_info->volume_mutex);
1708         init_rwsem(&fs_info->extent_commit_sem);
1709         init_rwsem(&fs_info->cleanup_work_sem);
1710         init_rwsem(&fs_info->subvol_sem);
1711
1712         btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
1713         btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
1714
1715         init_waitqueue_head(&fs_info->transaction_throttle);
1716         init_waitqueue_head(&fs_info->transaction_wait);
1717         init_waitqueue_head(&fs_info->transaction_blocked_wait);
1718         init_waitqueue_head(&fs_info->async_submit_wait);
1719
1720         __setup_root(4096, 4096, 4096, 4096, tree_root,
1721                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
1722
1723         bh = btrfs_read_dev_super(fs_devices->latest_bdev);
1724         if (!bh) {
1725                 err = -EINVAL;
1726                 goto fail_iput;
1727         }
1728
1729         memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1730         memcpy(&fs_info->super_for_commit, &fs_info->super_copy,
1731                sizeof(fs_info->super_for_commit));
1732         brelse(bh);
1733
1734         memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1735
1736         disk_super = &fs_info->super_copy;
1737         if (!btrfs_super_root(disk_super))
1738                 goto fail_iput;
1739
1740         ret = btrfs_parse_options(tree_root, options);
1741         if (ret) {
1742                 err = ret;
1743                 goto fail_iput;
1744         }
1745
1746         features = btrfs_super_incompat_flags(disk_super) &
1747                 ~BTRFS_FEATURE_INCOMPAT_SUPP;
1748         if (features) {
1749                 printk(KERN_ERR "BTRFS: couldn't mount because of "
1750                        "unsupported optional features (%Lx).\n",
1751                        (unsigned long long)features);
1752                 err = -EINVAL;
1753                 goto fail_iput;
1754         }
1755
1756         features = btrfs_super_incompat_flags(disk_super);
1757         features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
1758         if (tree_root->fs_info->compress_type & BTRFS_COMPRESS_LZO)
1759                 features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
1760         btrfs_set_super_incompat_flags(disk_super, features);
1761
1762         features = btrfs_super_compat_ro_flags(disk_super) &
1763                 ~BTRFS_FEATURE_COMPAT_RO_SUPP;
1764         if (!(sb->s_flags & MS_RDONLY) && features) {
1765                 printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
1766                        "unsupported option features (%Lx).\n",
1767                        (unsigned long long)features);
1768                 err = -EINVAL;
1769                 goto fail_iput;
1770         }
1771
1772         btrfs_init_workers(&fs_info->generic_worker,
1773                            "genwork", 1, NULL);
1774
1775         btrfs_init_workers(&fs_info->workers, "worker",
1776                            fs_info->thread_pool_size,
1777                            &fs_info->generic_worker);
1778
1779         btrfs_init_workers(&fs_info->delalloc_workers, "delalloc",
1780                            fs_info->thread_pool_size,
1781                            &fs_info->generic_worker);
1782
1783         btrfs_init_workers(&fs_info->submit_workers, "submit",
1784                            min_t(u64, fs_devices->num_devices,
1785                            fs_info->thread_pool_size),
1786                            &fs_info->generic_worker);
1787
1788         /* a higher idle thresh on the submit workers makes it much more
1789          * likely that bios will be send down in a sane order to the
1790          * devices
1791          */
1792         fs_info->submit_workers.idle_thresh = 64;
1793
1794         fs_info->workers.idle_thresh = 16;
1795         fs_info->workers.ordered = 1;
1796
1797         fs_info->delalloc_workers.idle_thresh = 2;
1798         fs_info->delalloc_workers.ordered = 1;
1799
1800         btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
1801                            &fs_info->generic_worker);
1802         btrfs_init_workers(&fs_info->endio_workers, "endio",
1803                            fs_info->thread_pool_size,
1804                            &fs_info->generic_worker);
1805         btrfs_init_workers(&fs_info->endio_meta_workers, "endio-meta",
1806                            fs_info->thread_pool_size,
1807                            &fs_info->generic_worker);
1808         btrfs_init_workers(&fs_info->endio_meta_write_workers,
1809                            "endio-meta-write", fs_info->thread_pool_size,
1810                            &fs_info->generic_worker);
1811         btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
1812                            fs_info->thread_pool_size,
1813                            &fs_info->generic_worker);
1814         btrfs_init_workers(&fs_info->endio_freespace_worker, "freespace-write",
1815                            1, &fs_info->generic_worker);
1816
1817         /*
1818          * endios are largely parallel and should have a very
1819          * low idle thresh
1820          */
1821         fs_info->endio_workers.idle_thresh = 4;
1822         fs_info->endio_meta_workers.idle_thresh = 4;
1823
1824         fs_info->endio_write_workers.idle_thresh = 2;
1825         fs_info->endio_meta_write_workers.idle_thresh = 2;
1826
1827         btrfs_start_workers(&fs_info->workers, 1);
1828         btrfs_start_workers(&fs_info->generic_worker, 1);
1829         btrfs_start_workers(&fs_info->submit_workers, 1);
1830         btrfs_start_workers(&fs_info->delalloc_workers, 1);
1831         btrfs_start_workers(&fs_info->fixup_workers, 1);
1832         btrfs_start_workers(&fs_info->endio_workers, 1);
1833         btrfs_start_workers(&fs_info->endio_meta_workers, 1);
1834         btrfs_start_workers(&fs_info->endio_meta_write_workers, 1);
1835         btrfs_start_workers(&fs_info->endio_write_workers, 1);
1836         btrfs_start_workers(&fs_info->endio_freespace_worker, 1);
1837
1838         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1839         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
1840                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
1841
1842         nodesize = btrfs_super_nodesize(disk_super);
1843         leafsize = btrfs_super_leafsize(disk_super);
1844         sectorsize = btrfs_super_sectorsize(disk_super);
1845         stripesize = btrfs_super_stripesize(disk_super);
1846         tree_root->nodesize = nodesize;
1847         tree_root->leafsize = leafsize;
1848         tree_root->sectorsize = sectorsize;
1849         tree_root->stripesize = stripesize;
1850
1851         sb->s_blocksize = sectorsize;
1852         sb->s_blocksize_bits = blksize_bits(sectorsize);
1853
1854         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1855                     sizeof(disk_super->magic))) {
1856                 printk(KERN_INFO "btrfs: valid FS not found on %s\n", sb->s_id);
1857                 goto fail_sb_buffer;
1858         }
1859
1860         mutex_lock(&fs_info->chunk_mutex);
1861         ret = btrfs_read_sys_array(tree_root);
1862         mutex_unlock(&fs_info->chunk_mutex);
1863         if (ret) {
1864                 printk(KERN_WARNING "btrfs: failed to read the system "
1865                        "array on %s\n", sb->s_id);
1866                 goto fail_sb_buffer;
1867         }
1868
1869         blocksize = btrfs_level_size(tree_root,
1870                                      btrfs_super_chunk_root_level(disk_super));
1871         generation = btrfs_super_chunk_root_generation(disk_super);
1872
1873         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1874                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1875
1876         chunk_root->node = read_tree_block(chunk_root,
1877                                            btrfs_super_chunk_root(disk_super),
1878                                            blocksize, generation);
1879         BUG_ON(!chunk_root->node);
1880         if (!test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
1881                 printk(KERN_WARNING "btrfs: failed to read chunk root on %s\n",
1882                        sb->s_id);
1883                 goto fail_chunk_root;
1884         }
1885         btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
1886         chunk_root->commit_root = btrfs_root_node(chunk_root);
1887
1888         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
1889            (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
1890            BTRFS_UUID_SIZE);
1891
1892         mutex_lock(&fs_info->chunk_mutex);
1893         ret = btrfs_read_chunk_tree(chunk_root);
1894         mutex_unlock(&fs_info->chunk_mutex);
1895         if (ret) {
1896                 printk(KERN_WARNING "btrfs: failed to read chunk tree on %s\n",
1897                        sb->s_id);
1898                 goto fail_chunk_root;
1899         }
1900
1901         btrfs_close_extra_devices(fs_devices);
1902
1903         blocksize = btrfs_level_size(tree_root,
1904                                      btrfs_super_root_level(disk_super));
1905         generation = btrfs_super_generation(disk_super);
1906
1907         tree_root->node = read_tree_block(tree_root,
1908                                           btrfs_super_root(disk_super),
1909                                           blocksize, generation);
1910         if (!tree_root->node)
1911                 goto fail_chunk_root;
1912         if (!test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
1913                 printk(KERN_WARNING "btrfs: failed to read tree root on %s\n",
1914                        sb->s_id);
1915                 goto fail_tree_root;
1916         }
1917         btrfs_set_root_node(&tree_root->root_item, tree_root->node);
1918         tree_root->commit_root = btrfs_root_node(tree_root);
1919
1920         ret = find_and_setup_root(tree_root, fs_info,
1921                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
1922         if (ret)
1923                 goto fail_tree_root;
1924         extent_root->track_dirty = 1;
1925
1926         ret = find_and_setup_root(tree_root, fs_info,
1927                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
1928         if (ret)
1929                 goto fail_extent_root;
1930         dev_root->track_dirty = 1;
1931
1932         ret = find_and_setup_root(tree_root, fs_info,
1933                                   BTRFS_CSUM_TREE_OBJECTID, csum_root);
1934         if (ret)
1935                 goto fail_dev_root;
1936
1937         csum_root->track_dirty = 1;
1938
1939         fs_info->generation = generation;
1940         fs_info->last_trans_committed = generation;
1941         fs_info->data_alloc_profile = (u64)-1;
1942         fs_info->metadata_alloc_profile = (u64)-1;
1943         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
1944
1945         ret = btrfs_read_block_groups(extent_root);
1946         if (ret) {
1947                 printk(KERN_ERR "Failed to read block groups: %d\n", ret);
1948                 goto fail_block_groups;
1949         }
1950
1951         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
1952                                                "btrfs-cleaner");
1953         if (IS_ERR(fs_info->cleaner_kthread))
1954                 goto fail_block_groups;
1955
1956         fs_info->transaction_kthread = kthread_run(transaction_kthread,
1957                                                    tree_root,
1958                                                    "btrfs-transaction");
1959         if (IS_ERR(fs_info->transaction_kthread))
1960                 goto fail_cleaner;
1961
1962         if (!btrfs_test_opt(tree_root, SSD) &&
1963             !btrfs_test_opt(tree_root, NOSSD) &&
1964             !fs_info->fs_devices->rotating) {
1965                 printk(KERN_INFO "Btrfs detected SSD devices, enabling SSD "
1966                        "mode\n");
1967                 btrfs_set_opt(fs_info->mount_opt, SSD);
1968         }
1969
1970         if (btrfs_super_log_root(disk_super) != 0) {
1971                 u64 bytenr = btrfs_super_log_root(disk_super);
1972
1973                 if (fs_devices->rw_devices == 0) {
1974                         printk(KERN_WARNING "Btrfs log replay required "
1975                                "on RO media\n");
1976                         err = -EIO;
1977                         goto fail_trans_kthread;
1978                 }
1979                 blocksize =
1980                      btrfs_level_size(tree_root,
1981                                       btrfs_super_log_root_level(disk_super));
1982
1983                 log_tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
1984                 if (!log_tree_root) {
1985                         err = -ENOMEM;
1986                         goto fail_trans_kthread;
1987                 }
1988
1989                 __setup_root(nodesize, leafsize, sectorsize, stripesize,
1990                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1991
1992                 log_tree_root->node = read_tree_block(tree_root, bytenr,
1993                                                       blocksize,
1994                                                       generation + 1);
1995                 ret = btrfs_recover_log_trees(log_tree_root);
1996                 BUG_ON(ret);
1997
1998                 if (sb->s_flags & MS_RDONLY) {
1999                         ret =  btrfs_commit_super(tree_root);
2000                         BUG_ON(ret);
2001                 }
2002         }
2003
2004         ret = btrfs_find_orphan_roots(tree_root);
2005         BUG_ON(ret);
2006
2007         if (!(sb->s_flags & MS_RDONLY)) {
2008                 ret = btrfs_cleanup_fs_roots(fs_info);
2009                 BUG_ON(ret);
2010
2011                 ret = btrfs_recover_relocation(tree_root);
2012                 if (ret < 0) {
2013                         printk(KERN_WARNING
2014                                "btrfs: failed to recover relocation\n");
2015                         err = -EINVAL;
2016                         goto fail_trans_kthread;
2017                 }
2018         }
2019
2020         location.objectid = BTRFS_FS_TREE_OBJECTID;
2021         location.type = BTRFS_ROOT_ITEM_KEY;
2022         location.offset = (u64)-1;
2023
2024         fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
2025         if (!fs_info->fs_root)
2026                 goto fail_trans_kthread;
2027         if (IS_ERR(fs_info->fs_root)) {
2028                 err = PTR_ERR(fs_info->fs_root);
2029                 goto fail_trans_kthread;
2030         }
2031
2032         if (!(sb->s_flags & MS_RDONLY)) {
2033                 down_read(&fs_info->cleanup_work_sem);
2034                 btrfs_orphan_cleanup(fs_info->fs_root);
2035                 btrfs_orphan_cleanup(fs_info->tree_root);
2036                 up_read(&fs_info->cleanup_work_sem);
2037         }
2038
2039         return tree_root;
2040
2041 fail_trans_kthread:
2042         kthread_stop(fs_info->transaction_kthread);
2043 fail_cleaner:
2044         kthread_stop(fs_info->cleaner_kthread);
2045
2046         /*
2047          * make sure we're done with the btree inode before we stop our
2048          * kthreads
2049          */
2050         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
2051         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2052
2053 fail_block_groups:
2054         btrfs_free_block_groups(fs_info);
2055         free_extent_buffer(csum_root->node);
2056         free_extent_buffer(csum_root->commit_root);
2057 fail_dev_root:
2058         free_extent_buffer(dev_root->node);
2059         free_extent_buffer(dev_root->commit_root);
2060 fail_extent_root:
2061         free_extent_buffer(extent_root->node);
2062         free_extent_buffer(extent_root->commit_root);
2063 fail_tree_root:
2064         free_extent_buffer(tree_root->node);
2065         free_extent_buffer(tree_root->commit_root);
2066 fail_chunk_root:
2067         free_extent_buffer(chunk_root->node);
2068         free_extent_buffer(chunk_root->commit_root);
2069 fail_sb_buffer:
2070         btrfs_stop_workers(&fs_info->generic_worker);
2071         btrfs_stop_workers(&fs_info->fixup_workers);
2072         btrfs_stop_workers(&fs_info->delalloc_workers);
2073         btrfs_stop_workers(&fs_info->workers);
2074         btrfs_stop_workers(&fs_info->endio_workers);
2075         btrfs_stop_workers(&fs_info->endio_meta_workers);
2076         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2077         btrfs_stop_workers(&fs_info->endio_write_workers);
2078         btrfs_stop_workers(&fs_info->endio_freespace_worker);
2079         btrfs_stop_workers(&fs_info->submit_workers);
2080 fail_iput:
2081         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2082         iput(fs_info->btree_inode);
2083
2084         btrfs_close_devices(fs_info->fs_devices);
2085         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2086 fail_bdi:
2087         bdi_destroy(&fs_info->bdi);
2088 fail_srcu:
2089         cleanup_srcu_struct(&fs_info->subvol_srcu);
2090 fail:
2091         kfree(extent_root);
2092         kfree(tree_root);
2093         kfree(fs_info);
2094         kfree(chunk_root);
2095         kfree(dev_root);
2096         kfree(csum_root);
2097         return ERR_PTR(err);
2098 }
2099
2100 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
2101 {
2102         char b[BDEVNAME_SIZE];
2103
2104         if (uptodate) {
2105                 set_buffer_uptodate(bh);
2106         } else {
2107                 if (!buffer_eopnotsupp(bh) && printk_ratelimit()) {
2108                         printk(KERN_WARNING "lost page write due to "
2109                                         "I/O error on %s\n",
2110                                        bdevname(bh->b_bdev, b));
2111                 }
2112                 /* note, we dont' set_buffer_write_io_error because we have
2113                  * our own ways of dealing with the IO errors
2114                  */
2115                 clear_buffer_uptodate(bh);
2116         }
2117         unlock_buffer(bh);
2118         put_bh(bh);
2119 }
2120
2121 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
2122 {
2123         struct buffer_head *bh;
2124         struct buffer_head *latest = NULL;
2125         struct btrfs_super_block *super;
2126         int i;
2127         u64 transid = 0;
2128         u64 bytenr;
2129
2130         /* we would like to check all the supers, but that would make
2131          * a btrfs mount succeed after a mkfs from a different FS.
2132          * So, we need to add a special mount option to scan for
2133          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
2134          */
2135         for (i = 0; i < 1; i++) {
2136                 bytenr = btrfs_sb_offset(i);
2137                 if (bytenr + 4096 >= i_size_read(bdev->bd_inode))
2138                         break;
2139                 bh = __bread(bdev, bytenr / 4096, 4096);
2140                 if (!bh)
2141                         continue;
2142
2143                 super = (struct btrfs_super_block *)bh->b_data;
2144                 if (btrfs_super_bytenr(super) != bytenr ||
2145                     strncmp((char *)(&super->magic), BTRFS_MAGIC,
2146                             sizeof(super->magic))) {
2147                         brelse(bh);
2148                         continue;
2149                 }
2150
2151                 if (!latest || btrfs_super_generation(super) > transid) {
2152                         brelse(latest);
2153                         latest = bh;
2154                         transid = btrfs_super_generation(super);
2155                 } else {
2156                         brelse(bh);
2157                 }
2158         }
2159         return latest;
2160 }
2161
2162 /*
2163  * this should be called twice, once with wait == 0 and
2164  * once with wait == 1.  When wait == 0 is done, all the buffer heads
2165  * we write are pinned.
2166  *
2167  * They are released when wait == 1 is done.
2168  * max_mirrors must be the same for both runs, and it indicates how
2169  * many supers on this one device should be written.
2170  *
2171  * max_mirrors == 0 means to write them all.
2172  */
2173 static int write_dev_supers(struct btrfs_device *device,
2174                             struct btrfs_super_block *sb,
2175                             int do_barriers, int wait, int max_mirrors)
2176 {
2177         struct buffer_head *bh;
2178         int i;
2179         int ret;
2180         int errors = 0;
2181         u32 crc;
2182         u64 bytenr;
2183         int last_barrier = 0;
2184
2185         if (max_mirrors == 0)
2186                 max_mirrors = BTRFS_SUPER_MIRROR_MAX;
2187
2188         /* make sure only the last submit_bh does a barrier */
2189         if (do_barriers) {
2190                 for (i = 0; i < max_mirrors; i++) {
2191                         bytenr = btrfs_sb_offset(i);
2192                         if (bytenr + BTRFS_SUPER_INFO_SIZE >=
2193                             device->total_bytes)
2194                                 break;
2195                         last_barrier = i;
2196                 }
2197         }
2198
2199         for (i = 0; i < max_mirrors; i++) {
2200                 bytenr = btrfs_sb_offset(i);
2201                 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
2202                         break;
2203
2204                 if (wait) {
2205                         bh = __find_get_block(device->bdev, bytenr / 4096,
2206                                               BTRFS_SUPER_INFO_SIZE);
2207                         BUG_ON(!bh);
2208                         wait_on_buffer(bh);
2209                         if (!buffer_uptodate(bh))
2210                                 errors++;
2211
2212                         /* drop our reference */
2213                         brelse(bh);
2214
2215                         /* drop the reference from the wait == 0 run */
2216                         brelse(bh);
2217                         continue;
2218                 } else {
2219                         btrfs_set_super_bytenr(sb, bytenr);
2220
2221                         crc = ~(u32)0;
2222                         crc = btrfs_csum_data(NULL, (char *)sb +
2223                                               BTRFS_CSUM_SIZE, crc,
2224                                               BTRFS_SUPER_INFO_SIZE -
2225                                               BTRFS_CSUM_SIZE);
2226                         btrfs_csum_final(crc, sb->csum);
2227
2228                         /*
2229                          * one reference for us, and we leave it for the
2230                          * caller
2231                          */
2232                         bh = __getblk(device->bdev, bytenr / 4096,
2233                                       BTRFS_SUPER_INFO_SIZE);
2234                         memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
2235
2236                         /* one reference for submit_bh */
2237                         get_bh(bh);
2238
2239                         set_buffer_uptodate(bh);
2240                         lock_buffer(bh);
2241                         bh->b_end_io = btrfs_end_buffer_write_sync;
2242                 }
2243
2244                 if (i == last_barrier && do_barriers && device->barriers) {
2245                         ret = submit_bh(WRITE_BARRIER, bh);
2246                         if (ret == -EOPNOTSUPP) {
2247                                 printk("btrfs: disabling barriers on dev %s\n",
2248                                        device->name);
2249                                 set_buffer_uptodate(bh);
2250                                 device->barriers = 0;
2251                                 /* one reference for submit_bh */
2252                                 get_bh(bh);
2253                                 lock_buffer(bh);
2254                                 ret = submit_bh(WRITE_SYNC, bh);
2255                         }
2256                 } else {
2257                         ret = submit_bh(WRITE_SYNC, bh);
2258                 }
2259
2260                 if (ret)
2261                         errors++;
2262         }
2263         return errors < i ? 0 : -1;
2264 }
2265
2266 int write_all_supers(struct btrfs_root *root, int max_mirrors)
2267 {
2268         struct list_head *head;
2269         struct btrfs_device *dev;
2270         struct btrfs_super_block *sb;
2271         struct btrfs_dev_item *dev_item;
2272         int ret;
2273         int do_barriers;
2274         int max_errors;
2275         int total_errors = 0;
2276         u64 flags;
2277
2278         max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
2279         do_barriers = !btrfs_test_opt(root, NOBARRIER);
2280
2281         sb = &root->fs_info->super_for_commit;
2282         dev_item = &sb->dev_item;
2283
2284         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2285         head = &root->fs_info->fs_devices->devices;
2286         list_for_each_entry(dev, head, dev_list) {
2287                 if (!dev->bdev) {
2288                         total_errors++;
2289                         continue;
2290                 }
2291                 if (!dev->in_fs_metadata || !dev->writeable)
2292                         continue;
2293
2294                 btrfs_set_stack_device_generation(dev_item, 0);
2295                 btrfs_set_stack_device_type(dev_item, dev->type);
2296                 btrfs_set_stack_device_id(dev_item, dev->devid);
2297                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
2298                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
2299                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
2300                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
2301                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
2302                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
2303                 memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
2304
2305                 flags = btrfs_super_flags(sb);
2306                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
2307
2308                 ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
2309                 if (ret)
2310                         total_errors++;
2311         }
2312         if (total_errors > max_errors) {
2313                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2314                        total_errors);
2315                 BUG();
2316         }
2317
2318         total_errors = 0;
2319         list_for_each_entry(dev, head, dev_list) {
2320                 if (!dev->bdev)
2321                         continue;
2322                 if (!dev->in_fs_metadata || !dev->writeable)
2323                         continue;
2324
2325                 ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
2326                 if (ret)
2327                         total_errors++;
2328         }
2329         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2330         if (total_errors > max_errors) {
2331                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2332                        total_errors);
2333                 BUG();
2334         }
2335         return 0;
2336 }
2337
2338 int write_ctree_super(struct btrfs_trans_handle *trans,
2339                       struct btrfs_root *root, int max_mirrors)
2340 {
2341         int ret;
2342
2343         ret = write_all_supers(root, max_mirrors);
2344         return ret;
2345 }
2346
2347 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2348 {
2349         spin_lock(&fs_info->fs_roots_radix_lock);
2350         radix_tree_delete(&fs_info->fs_roots_radix,
2351                           (unsigned long)root->root_key.objectid);
2352         spin_unlock(&fs_info->fs_roots_radix_lock);
2353
2354         if (btrfs_root_refs(&root->root_item) == 0)
2355                 synchronize_srcu(&fs_info->subvol_srcu);
2356
2357         free_fs_root(root);
2358         return 0;
2359 }
2360
2361 static void free_fs_root(struct btrfs_root *root)
2362 {
2363         WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
2364         if (root->anon_super.s_dev) {
2365                 down_write(&root->anon_super.s_umount);
2366                 kill_anon_super(&root->anon_super);
2367         }
2368         free_extent_buffer(root->node);
2369         free_extent_buffer(root->commit_root);
2370         kfree(root->name);
2371         kfree(root);
2372 }
2373
2374 static int del_fs_roots(struct btrfs_fs_info *fs_info)
2375 {
2376         int ret;
2377         struct btrfs_root *gang[8];
2378         int i;
2379
2380         while (!list_empty(&fs_info->dead_roots)) {
2381                 gang[0] = list_entry(fs_info->dead_roots.next,
2382                                      struct btrfs_root, root_list);
2383                 list_del(&gang[0]->root_list);
2384
2385                 if (gang[0]->in_radix) {
2386                         btrfs_free_fs_root(fs_info, gang[0]);
2387                 } else {
2388                         free_extent_buffer(gang[0]->node);
2389                         free_extent_buffer(gang[0]->commit_root);
2390                         kfree(gang[0]);
2391                 }
2392         }
2393
2394         while (1) {
2395                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2396                                              (void **)gang, 0,
2397                                              ARRAY_SIZE(gang));
2398                 if (!ret)
2399                         break;
2400                 for (i = 0; i < ret; i++)
2401                         btrfs_free_fs_root(fs_info, gang[i]);
2402         }
2403         return 0;
2404 }
2405
2406 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
2407 {
2408         u64 root_objectid = 0;
2409         struct btrfs_root *gang[8];
2410         int i;
2411         int ret;
2412
2413         while (1) {
2414                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2415                                              (void **)gang, root_objectid,
2416                                              ARRAY_SIZE(gang));
2417                 if (!ret)
2418                         break;
2419
2420                 root_objectid = gang[ret - 1]->root_key.objectid + 1;
2421                 for (i = 0; i < ret; i++) {
2422                         root_objectid = gang[i]->root_key.objectid;
2423                         btrfs_orphan_cleanup(gang[i]);
2424                 }
2425                 root_objectid++;
2426         }
2427         return 0;
2428 }
2429
2430 int btrfs_commit_super(struct btrfs_root *root)
2431 {
2432         struct btrfs_trans_handle *trans;
2433         int ret;
2434
2435         mutex_lock(&root->fs_info->cleaner_mutex);
2436         btrfs_run_delayed_iputs(root);
2437         btrfs_clean_old_snapshots(root);
2438         mutex_unlock(&root->fs_info->cleaner_mutex);
2439
2440         /* wait until ongoing cleanup work done */
2441         down_write(&root->fs_info->cleanup_work_sem);
2442         up_write(&root->fs_info->cleanup_work_sem);
2443
2444         trans = btrfs_join_transaction(root, 1);
2445         ret = btrfs_commit_transaction(trans, root);
2446         BUG_ON(ret);
2447         /* run commit again to drop the original snapshot */
2448         trans = btrfs_join_transaction(root, 1);
2449         btrfs_commit_transaction(trans, root);
2450         ret = btrfs_write_and_wait_transaction(NULL, root);
2451         BUG_ON(ret);
2452
2453         ret = write_ctree_super(NULL, root, 0);
2454         return ret;
2455 }
2456
2457 int close_ctree(struct btrfs_root *root)
2458 {
2459         struct btrfs_fs_info *fs_info = root->fs_info;
2460         int ret;
2461
2462         fs_info->closing = 1;
2463         smp_mb();
2464
2465         btrfs_put_block_group_cache(fs_info);
2466         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
2467                 ret =  btrfs_commit_super(root);
2468                 if (ret)
2469                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
2470         }
2471
2472         kthread_stop(root->fs_info->transaction_kthread);
2473         kthread_stop(root->fs_info->cleaner_kthread);
2474
2475         fs_info->closing = 2;
2476         smp_mb();
2477
2478         if (fs_info->delalloc_bytes) {
2479                 printk(KERN_INFO "btrfs: at unmount delalloc count %llu\n",
2480                        (unsigned long long)fs_info->delalloc_bytes);
2481         }
2482         if (fs_info->total_ref_cache_size) {
2483                 printk(KERN_INFO "btrfs: at umount reference cache size %llu\n",
2484                        (unsigned long long)fs_info->total_ref_cache_size);
2485         }
2486
2487         free_extent_buffer(fs_info->extent_root->node);
2488         free_extent_buffer(fs_info->extent_root->commit_root);
2489         free_extent_buffer(fs_info->tree_root->node);
2490         free_extent_buffer(fs_info->tree_root->commit_root);
2491         free_extent_buffer(root->fs_info->chunk_root->node);
2492         free_extent_buffer(root->fs_info->chunk_root->commit_root);
2493         free_extent_buffer(root->fs_info->dev_root->node);
2494         free_extent_buffer(root->fs_info->dev_root->commit_root);
2495         free_extent_buffer(root->fs_info->csum_root->node);
2496         free_extent_buffer(root->fs_info->csum_root->commit_root);
2497
2498         btrfs_free_block_groups(root->fs_info);
2499
2500         del_fs_roots(fs_info);
2501
2502         iput(fs_info->btree_inode);
2503
2504         btrfs_stop_workers(&fs_info->generic_worker);
2505         btrfs_stop_workers(&fs_info->fixup_workers);
2506         btrfs_stop_workers(&fs_info->delalloc_workers);
2507         btrfs_stop_workers(&fs_info->workers);
2508         btrfs_stop_workers(&fs_info->endio_workers);
2509         btrfs_stop_workers(&fs_info->endio_meta_workers);
2510         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2511         btrfs_stop_workers(&fs_info->endio_write_workers);
2512         btrfs_stop_workers(&fs_info->endio_freespace_worker);
2513         btrfs_stop_workers(&fs_info->submit_workers);
2514
2515         btrfs_close_devices(fs_info->fs_devices);
2516         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2517
2518         bdi_destroy(&fs_info->bdi);
2519         cleanup_srcu_struct(&fs_info->subvol_srcu);
2520
2521         kfree(fs_info->extent_root);
2522         kfree(fs_info->tree_root);
2523         kfree(fs_info->chunk_root);
2524         kfree(fs_info->dev_root);
2525         kfree(fs_info->csum_root);
2526         return 0;
2527 }
2528
2529 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
2530 {
2531         int ret;
2532         struct inode *btree_inode = buf->first_page->mapping->host;
2533
2534         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf,
2535                                      NULL);
2536         if (!ret)
2537                 return ret;
2538
2539         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
2540                                     parent_transid);
2541         return !ret;
2542 }
2543
2544 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
2545 {
2546         struct inode *btree_inode = buf->first_page->mapping->host;
2547         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
2548                                           buf);
2549 }
2550
2551 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
2552 {
2553         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2554         u64 transid = btrfs_header_generation(buf);
2555         struct inode *btree_inode = root->fs_info->btree_inode;
2556         int was_dirty;
2557
2558         btrfs_assert_tree_locked(buf);
2559         if (transid != root->fs_info->generation) {
2560                 printk(KERN_CRIT "btrfs transid mismatch buffer %llu, "
2561                        "found %llu running %llu\n",
2562                         (unsigned long long)buf->start,
2563                         (unsigned long long)transid,
2564                         (unsigned long long)root->fs_info->generation);
2565                 WARN_ON(1);
2566         }
2567         was_dirty = set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
2568                                             buf);
2569         if (!was_dirty) {
2570                 spin_lock(&root->fs_info->delalloc_lock);
2571                 root->fs_info->dirty_metadata_bytes += buf->len;
2572                 spin_unlock(&root->fs_info->delalloc_lock);
2573         }
2574 }
2575
2576 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
2577 {
2578         /*
2579          * looks as though older kernels can get into trouble with
2580          * this code, they end up stuck in balance_dirty_pages forever
2581          */
2582         u64 num_dirty;
2583         unsigned long thresh = 32 * 1024 * 1024;
2584
2585         if (current->flags & PF_MEMALLOC)
2586                 return;
2587
2588         num_dirty = root->fs_info->dirty_metadata_bytes;
2589
2590         if (num_dirty > thresh) {
2591                 balance_dirty_pages_ratelimited_nr(
2592                                    root->fs_info->btree_inode->i_mapping, 1);
2593         }
2594         return;
2595 }
2596
2597 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
2598 {
2599         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2600         int ret;
2601         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
2602         if (ret == 0)
2603                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
2604         return ret;
2605 }
2606
2607 int btree_lock_page_hook(struct page *page)
2608 {
2609         struct inode *inode = page->mapping->host;
2610         struct btrfs_root *root = BTRFS_I(inode)->root;
2611         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2612         struct extent_buffer *eb;
2613         unsigned long len;
2614         u64 bytenr = page_offset(page);
2615
2616         if (page->private == EXTENT_PAGE_PRIVATE)
2617                 goto out;
2618
2619         len = page->private >> 2;
2620         eb = find_extent_buffer(io_tree, bytenr, len, GFP_NOFS);
2621         if (!eb)
2622                 goto out;
2623
2624         btrfs_tree_lock(eb);
2625         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
2626
2627         if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
2628                 spin_lock(&root->fs_info->delalloc_lock);
2629                 if (root->fs_info->dirty_metadata_bytes >= eb->len)
2630                         root->fs_info->dirty_metadata_bytes -= eb->len;
2631                 else
2632                         WARN_ON(1);
2633                 spin_unlock(&root->fs_info->delalloc_lock);
2634         }
2635
2636         btrfs_tree_unlock(eb);
2637         free_extent_buffer(eb);
2638 out:
2639         lock_page(page);
2640         return 0;
2641 }
2642
2643 static struct extent_io_ops btree_extent_io_ops = {
2644         .write_cache_pages_lock_hook = btree_lock_page_hook,
2645         .readpage_end_io_hook = btree_readpage_end_io_hook,
2646         .submit_bio_hook = btree_submit_bio_hook,
2647         /* note we're sharing with inode.c for the merge bio hook */
2648         .merge_bio_hook = btrfs_merge_bio_hook,
2649 };