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