git.oblomov.eu Git - linux-2.6/blob - 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/crc32c.h>
  22 #include <linux/scatterlist.h>
  23 #include <linux/swap.h>
  24 #include <linux/radix-tree.h>
  25 #include <linux/writeback.h>
  26 #include <linux/buffer_head.h> // for block_sync_page
  27 #include <linux/workqueue.h>
  28 #include "ctree.h"
  29 #include "disk-io.h"
  30 #include "transaction.h"
  31 #include "btrfs_inode.h"
  32 #include "volumes.h"
  33 #include "print-tree.h"
  34
  35 #if 0
  36 static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
  37 {
  38         if (extent_buffer_blocknr(buf) != btrfs_header_blocknr(buf)) {
  39                 printk(KERN_CRIT "buf blocknr(buf) is %llu, header is %llu\n",
  40                        (unsigned long long)extent_buffer_blocknr(buf),
  41                        (unsigned long long)btrfs_header_blocknr(buf));
  42                 return 1;
  43         }
  44         return 0;
  45 }
  46 #endif
  47
  48 static struct extent_io_ops btree_extent_io_ops;
  49 static struct workqueue_struct *end_io_workqueue;
  50
  51 struct end_io_wq {
  52         struct bio *bio;
  53         bio_end_io_t *end_io;
  54         void *private;
  55         struct btrfs_fs_info *info;
  56         int error;
  57         int metadata;
  58         struct list_head list;
  59 };
  60
  61 struct extent_map *btree_get_extent(struct inode *inode, struct page *page,
  62                                     size_t page_offset, u64 start, u64 len,
  63                                     int create)
  64 {
  65         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
  66         struct extent_map *em;
  67         int ret;
  68
  69 again:
  70         spin_lock(&em_tree->lock);
  71         em = lookup_extent_mapping(em_tree, start, len);
  72         spin_unlock(&em_tree->lock);
  73         if (em) {
  74                 goto out;
  75         }
  76         em = alloc_extent_map(GFP_NOFS);
  77         if (!em) {
  78                 em = ERR_PTR(-ENOMEM);
  79                 goto out;
  80         }
  81         em->start = 0;
  82         em->len = i_size_read(inode);
  83         em->block_start = 0;
  84         em->bdev = inode->i_sb->s_bdev;
  85
  86         spin_lock(&em_tree->lock);
  87         ret = add_extent_mapping(em_tree, em);
  88         spin_unlock(&em_tree->lock);
  89
  90         if (ret == -EEXIST) {
  91                 free_extent_map(em);
  92                 em = NULL;
  93                 goto again;
  94         } else if (ret) {
  95                 em = ERR_PTR(ret);
  96         }
  97 out:
  98         return em;
  99 }
 100
 101 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
 102 {
 103         return crc32c(seed, data, len);
 104 }
 105
 106 void btrfs_csum_final(u32 crc, char *result)
 107 {
 108         *(__le32 *)result = ~cpu_to_le32(crc);
 109 }
 110
 111 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
 112                            int verify)
 113 {
 114         char result[BTRFS_CRC32_SIZE];
 115         unsigned long len;
 116         unsigned long cur_len;
 117         unsigned long offset = BTRFS_CSUM_SIZE;
 118         char *map_token = NULL;
 119         char *kaddr;
 120         unsigned long map_start;
 121         unsigned long map_len;
 122         int err;
 123         u32 crc = ~(u32)0;
 124
 125         len = buf->len - offset;
 126         while(len > 0) {
 127                 err = map_private_extent_buffer(buf, offset, 32,
 128                                         &map_token, &kaddr,
 129                                         &map_start, &map_len, KM_USER0);
 130                 if (err) {
 131                         printk("failed to map extent buffer! %lu\n",
 132                                offset);
 133                         return 1;
 134                 }
 135                 cur_len = min(len, map_len - (offset - map_start));
 136                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
 137                                       crc, cur_len);
 138                 len -= cur_len;
 139                 offset += cur_len;
 140                 unmap_extent_buffer(buf, map_token, KM_USER0);
 141         }
 142         btrfs_csum_final(crc, result);
 143
 144         if (verify) {
 145                 int from_this_trans = 0;
 146
 147                 if (root->fs_info->running_transaction &&
 148                     btrfs_header_generation(buf) ==
 149                     root->fs_info->running_transaction->transid)
 150                         from_this_trans = 1;
 151
 152                 /* FIXME, this is not good */
 153                 if (memcmp_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE)) {
 154                         u32 val;
 155                         u32 found = 0;
 156                         memcpy(&found, result, BTRFS_CRC32_SIZE);
 157
 158                         read_extent_buffer(buf, &val, 0, BTRFS_CRC32_SIZE);
 159                         printk("btrfs: %s checksum verify failed on %llu "
 160                                "wanted %X found %X from_this_trans %d "
 161                                "level %d\n",
 162                                root->fs_info->sb->s_id,
 163                                buf->start, val, found, from_this_trans,
 164                                btrfs_header_level(buf));
 165                         return 1;
 166                 }
 167         } else {
 168                 write_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE);
 169         }
 170         return 0;
 171 }
 172
 173 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
 174                                           struct extent_buffer *eb,
 175                                           u64 start)
 176 {
 177         struct extent_io_tree *io_tree;
 178         int ret;
 179         int num_copies = 0;
 180         int mirror_num = 0;
 181
 182         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
 183         while (1) {
 184                 ret = read_extent_buffer_pages(io_tree, eb, start, 1,
 185                                                btree_get_extent, mirror_num);
 186                 if (!ret) {
 187                         if (mirror_num)
 188 printk("good read %Lu mirror %d total %d\n", eb->start, mirror_num, num_copies);
 189                         return ret;
 190                 }
 191                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
 192                                               eb->start, eb->len);
 193 printk("failed to read %Lu mirror %d total %d\n", eb->start, mirror_num, num_copies);
 194                 if (num_copies == 1) {
 195 printk("reading %Lu failed only one copy\n", eb->start);
 196                         return ret;
 197                 }
 198                 mirror_num++;
 199                 if (mirror_num > num_copies) {
 200 printk("bailing at mirror %d of %d\n", mirror_num, num_copies);
 201                         return ret;
 202                 }
 203         }
 204 printk("read extent buffer page last\n");
 205         return -EIO;
 206 }
 207
 208 int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
 209 {
 210         struct extent_io_tree *tree;
 211         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
 212         u64 found_start;
 213         int found_level;
 214         unsigned long len;
 215         struct extent_buffer *eb;
 216         int ret;
 217
 218         tree = &BTRFS_I(page->mapping->host)->io_tree;
 219
 220         if (page->private == EXTENT_PAGE_PRIVATE)
 221                 goto out;
 222         if (!page->private)
 223                 goto out;
 224         len = page->private >> 2;
 225         if (len == 0) {
 226                 WARN_ON(1);
 227         }
 228         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 229         ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE);
 230         BUG_ON(ret);
 231         btrfs_clear_buffer_defrag(eb);
 232         found_start = btrfs_header_bytenr(eb);
 233         if (found_start != start) {
 234                 printk("warning: eb start incorrect %Lu buffer %Lu len %lu\n",
 235                        start, found_start, len);
 236                 WARN_ON(1);
 237                 goto err;
 238         }
 239         if (eb->first_page != page) {
 240                 printk("bad first page %lu %lu\n", eb->first_page->index,
 241                        page->index);
 242                 WARN_ON(1);
 243                 goto err;
 244         }
 245         if (!PageUptodate(page)) {
 246                 printk("csum not up to date page %lu\n", page->index);
 247                 WARN_ON(1);
 248                 goto err;
 249         }
 250         found_level = btrfs_header_level(eb);
 251         spin_lock(&root->fs_info->hash_lock);
 252         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
 253         spin_unlock(&root->fs_info->hash_lock);
 254         csum_tree_block(root, eb, 0);
 255 err:
 256         free_extent_buffer(eb);
 257 out:
 258         return 0;
 259 }
 260
 261 static int btree_writepage_io_hook(struct page *page, u64 start, u64 end)
 262 {
 263         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 264
 265         csum_dirty_buffer(root, page);
 266         return 0;
 267 }
 268
 269 int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
 270                                struct extent_state *state)
 271 {
 272         struct extent_io_tree *tree;
 273         u64 found_start;
 274         int found_level;
 275         unsigned long len;
 276         struct extent_buffer *eb;
 277         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 278         int ret = 0;
 279
 280         tree = &BTRFS_I(page->mapping->host)->io_tree;
 281         if (page->private == EXTENT_PAGE_PRIVATE)
 282                 goto out;
 283         if (!page->private)
 284                 goto out;
 285         len = page->private >> 2;
 286         if (len == 0) {
 287                 WARN_ON(1);
 288         }
 289         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
 290
 291         btrfs_clear_buffer_defrag(eb);
 292         found_start = btrfs_header_bytenr(eb);
 293         if (found_start != start) {
 294 printk("bad start on %Lu found %Lu\n", eb->start, found_start);
 295                 ret = -EIO;
 296                 goto err;
 297         }
 298         if (eb->first_page != page) {
 299                 printk("bad first page %lu %lu\n", eb->first_page->index,
 300                        page->index);
 301                 WARN_ON(1);
 302                 ret = -EIO;
 303                 goto err;
 304         }
 305         found_level = btrfs_header_level(eb);
 306
 307         ret = csum_tree_block(root, eb, 1);
 308         if (ret)
 309                 ret = -EIO;
 310
 311         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
 312         end = eb->start + end - 1;
 313         release_extent_buffer_tail_pages(eb);
 314 err:
 315         free_extent_buffer(eb);
 316 out:
 317         return ret;
 318 }
 319
 320 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
 321 static void end_workqueue_bio(struct bio *bio, int err)
 322 #else
 323 static int end_workqueue_bio(struct bio *bio,
 324                                    unsigned int bytes_done, int err)
 325 #endif
 326 {
 327         struct end_io_wq *end_io_wq = bio->bi_private;
 328         struct btrfs_fs_info *fs_info;
 329         unsigned long flags;
 330
 331 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
 332         if (bio->bi_size)
 333                 return 1;
 334 #endif
 335
 336         fs_info = end_io_wq->info;
 337         spin_lock_irqsave(&fs_info->end_io_work_lock, flags);
 338         end_io_wq->error = err;
 339         list_add_tail(&end_io_wq->list, &fs_info->end_io_work_list);
 340         spin_unlock_irqrestore(&fs_info->end_io_work_lock, flags);
 341         queue_work(end_io_workqueue, &fs_info->end_io_work);
 342
 343 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
 344         return 0;
 345 #endif
 346 }
 347
 348 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
 349                         int metadata)
 350 {
 351         struct end_io_wq *end_io_wq;
 352         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
 353         if (!end_io_wq)
 354                 return -ENOMEM;
 355
 356         end_io_wq->private = bio->bi_private;
 357         end_io_wq->end_io = bio->bi_end_io;
 358         end_io_wq->info = info;
 359         end_io_wq->error = 0;
 360         end_io_wq->bio = bio;
 361         end_io_wq->metadata = metadata;
 362
 363         bio->bi_private = end_io_wq;
 364         bio->bi_end_io = end_workqueue_bio;
 365         return 0;
 366 }
 367
 368 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
 369                                  int mirror_num)
 370 {
 371         struct btrfs_root *root = BTRFS_I(inode)->root;
 372         u64 offset;
 373         int ret;
 374
 375         offset = bio->bi_sector << 9;
 376
 377         if (rw & (1 << BIO_RW)) {
 378                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num);
 379         }
 380
 381         ret = btrfs_bio_wq_end_io(root->fs_info, bio, 1);
 382         BUG_ON(ret);
 383
 384         if (offset == BTRFS_SUPER_INFO_OFFSET) {
 385                 bio->bi_bdev = root->fs_info->sb->s_bdev;
 386                 submit_bio(rw, bio);
 387                 return 0;
 388         }
 389         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num);
 390 }
 391
 392 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 393 {
 394         struct extent_io_tree *tree;
 395         tree = &BTRFS_I(page->mapping->host)->io_tree;
 396         return extent_write_full_page(tree, page, btree_get_extent, wbc);
 397 }
 398
 399 static int btree_writepages(struct address_space *mapping,
 400                             struct writeback_control *wbc)
 401 {
 402         struct extent_io_tree *tree;
 403         tree = &BTRFS_I(mapping->host)->io_tree;
 404         if (wbc->sync_mode == WB_SYNC_NONE) {
 405                 u64 num_dirty;
 406                 u64 start = 0;
 407                 unsigned long thresh = 96 * 1024 * 1024;
 408
 409                 if (wbc->for_kupdate)
 410                         return 0;
 411
 412                 if (current_is_pdflush()) {
 413                         thresh = 96 * 1024 * 1024;
 414                 } else {
 415                         thresh = 8 * 1024 * 1024;
 416                 }
 417                 num_dirty = count_range_bits(tree, &start, (u64)-1,
 418                                              thresh, EXTENT_DIRTY);
 419                 if (num_dirty < thresh) {
 420                         return 0;
 421                 }
 422         }
 423         return extent_writepages(tree, mapping, btree_get_extent, wbc);
 424 }
 425
 426 int btree_readpage(struct file *file, struct page *page)
 427 {
 428         struct extent_io_tree *tree;
 429         tree = &BTRFS_I(page->mapping->host)->io_tree;
 430         return extent_read_full_page(tree, page, btree_get_extent);
 431 }
 432
 433 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
 434 {
 435         struct extent_io_tree *tree;
 436         struct extent_map_tree *map;
 437         int ret;
 438
 439         tree = &BTRFS_I(page->mapping->host)->io_tree;
 440         map = &BTRFS_I(page->mapping->host)->extent_tree;
 441         ret = try_release_extent_mapping(map, tree, page, gfp_flags);
 442         if (ret == 1) {
 443                 invalidate_extent_lru(tree, page_offset(page), PAGE_CACHE_SIZE);
 444                 ClearPagePrivate(page);
 445                 set_page_private(page, 0);
 446                 page_cache_release(page);
 447         }
 448         return ret;
 449 }
 450
 451 static void btree_invalidatepage(struct page *page, unsigned long offset)
 452 {
 453         struct extent_io_tree *tree;
 454         tree = &BTRFS_I(page->mapping->host)->io_tree;
 455         extent_invalidatepage(tree, page, offset);
 456         btree_releasepage(page, GFP_NOFS);
 457 }
 458
 459 #if 0
 460 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 461 {
 462         struct buffer_head *bh;
 463         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 464         struct buffer_head *head;
 465         if (!page_has_buffers(page)) {
 466                 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
 467                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
 468         }
 469         head = page_buffers(page);
 470         bh = head;
 471         do {
 472                 if (buffer_dirty(bh))
 473                         csum_tree_block(root, bh, 0);
 474                 bh = bh->b_this_page;
 475         } while (bh != head);
 476         return block_write_full_page(page, btree_get_block, wbc);
 477 }
 478 #endif
 479
 480 static struct address_space_operations btree_aops = {
 481         .readpage       = btree_readpage,
 482         .writepage      = btree_writepage,
 483         .writepages     = btree_writepages,
 484         .releasepage    = btree_releasepage,
 485         .invalidatepage = btree_invalidatepage,
 486         .sync_page      = block_sync_page,
 487 };
 488
 489 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize)
 490 {
 491         struct extent_buffer *buf = NULL;
 492         struct inode *btree_inode = root->fs_info->btree_inode;
 493         int ret = 0;
 494
 495         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 496         if (!buf)
 497                 return 0;
 498         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
 499                                  buf, 0, 0, btree_get_extent, 0);
 500         free_extent_buffer(buf);
 501         return ret;
 502 }
 503
 504 static int close_all_devices(struct btrfs_fs_info *fs_info)
 505 {
 506         struct list_head *list;
 507         struct list_head *next;
 508         struct btrfs_device *device;
 509
 510         list = &fs_info->fs_devices->devices;
 511         list_for_each(next, list) {
 512                 device = list_entry(next, struct btrfs_device, dev_list);
 513                 if (device->bdev && device->bdev != fs_info->sb->s_bdev)
 514                         close_bdev_excl(device->bdev);
 515                 device->bdev = NULL;
 516         }
 517         return 0;
 518 }
 519
 520 int btrfs_verify_block_csum(struct btrfs_root *root,
 521                             struct extent_buffer *buf)
 522 {
 523         return btrfs_buffer_uptodate(buf);
 524 }
 525
 526 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
 527                                             u64 bytenr, u32 blocksize)
 528 {
 529         struct inode *btree_inode = root->fs_info->btree_inode;
 530         struct extent_buffer *eb;
 531         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 532                                 bytenr, blocksize, GFP_NOFS);
 533         return eb;
 534 }
 535
 536 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
 537                                                  u64 bytenr, u32 blocksize)
 538 {
 539         struct inode *btree_inode = root->fs_info->btree_inode;
 540         struct extent_buffer *eb;
 541
 542         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
 543                                  bytenr, blocksize, NULL, GFP_NOFS);
 544         return eb;
 545 }
 546
 547
 548 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
 549                                       u32 blocksize)
 550 {
 551         struct extent_buffer *buf = NULL;
 552         struct inode *btree_inode = root->fs_info->btree_inode;
 553         struct extent_io_tree *io_tree;
 554         int ret;
 555
 556         io_tree = &BTRFS_I(btree_inode)->io_tree;
 557
 558         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
 559         if (!buf)
 560                 return NULL;
 561
 562         ret = btree_read_extent_buffer_pages(root, buf, 0);
 563
 564         if (ret == 0) {
 565                 buf->flags |= EXTENT_UPTODATE;
 566         }
 567         return buf;
 568
 569 }
 570
 571 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 572                      struct extent_buffer *buf)
 573 {
 574         struct inode *btree_inode = root->fs_info->btree_inode;
 575         if (btrfs_header_generation(buf) ==
 576             root->fs_info->running_transaction->transid)
 577                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
 578                                           buf);
 579         return 0;
 580 }
 581
 582 int wait_on_tree_block_writeback(struct btrfs_root *root,
 583                                  struct extent_buffer *buf)
 584 {
 585         struct inode *btree_inode = root->fs_info->btree_inode;
 586         wait_on_extent_buffer_writeback(&BTRFS_I(btree_inode)->io_tree,
 587                                         buf);
 588         return 0;
 589 }
 590
 591 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
 592                         u32 stripesize, struct btrfs_root *root,
 593                         struct btrfs_fs_info *fs_info,
 594                         u64 objectid)
 595 {
 596         root->node = NULL;
 597         root->inode = NULL;
 598         root->commit_root = NULL;
 599         root->sectorsize = sectorsize;
 600         root->nodesize = nodesize;
 601         root->leafsize = leafsize;
 602         root->stripesize = stripesize;
 603         root->ref_cows = 0;
 604         root->track_dirty = 0;
 605
 606         root->fs_info = fs_info;
 607         root->objectid = objectid;
 608         root->last_trans = 0;
 609         root->highest_inode = 0;
 610         root->last_inode_alloc = 0;
 611         root->name = NULL;
 612         root->in_sysfs = 0;
 613
 614         INIT_LIST_HEAD(&root->dirty_list);
 615         memset(&root->root_key, 0, sizeof(root->root_key));
 616         memset(&root->root_item, 0, sizeof(root->root_item));
 617         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
 618         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
 619         init_completion(&root->kobj_unregister);
 620         root->defrag_running = 0;
 621         root->defrag_level = 0;
 622         root->root_key.objectid = objectid;
 623         return 0;
 624 }
 625
 626 static int find_and_setup_root(struct btrfs_root *tree_root,
 627                                struct btrfs_fs_info *fs_info,
 628                                u64 objectid,
 629                                struct btrfs_root *root)
 630 {
 631         int ret;
 632         u32 blocksize;
 633
 634         __setup_root(tree_root->nodesize, tree_root->leafsize,
 635                      tree_root->sectorsize, tree_root->stripesize,
 636                      root, fs_info, objectid);
 637         ret = btrfs_find_last_root(tree_root, objectid,
 638                                    &root->root_item, &root->root_key);
 639         BUG_ON(ret);
 640
 641         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 642         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 643                                      blocksize);
 644         BUG_ON(!root->node);
 645         return 0;
 646 }
 647
 648 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_fs_info *fs_info,
 649                                                struct btrfs_key *location)
 650 {
 651         struct btrfs_root *root;
 652         struct btrfs_root *tree_root = fs_info->tree_root;
 653         struct btrfs_path *path;
 654         struct extent_buffer *l;
 655         u64 highest_inode;
 656         u32 blocksize;
 657         int ret = 0;
 658
 659         root = kzalloc(sizeof(*root), GFP_NOFS);
 660         if (!root)
 661                 return ERR_PTR(-ENOMEM);
 662         if (location->offset == (u64)-1) {
 663                 ret = find_and_setup_root(tree_root, fs_info,
 664                                           location->objectid, root);
 665                 if (ret) {
 666                         kfree(root);
 667                         return ERR_PTR(ret);
 668                 }
 669                 goto insert;
 670         }
 671
 672         __setup_root(tree_root->nodesize, tree_root->leafsize,
 673                      tree_root->sectorsize, tree_root->stripesize,
 674                      root, fs_info, location->objectid);
 675
 676         path = btrfs_alloc_path();
 677         BUG_ON(!path);
 678         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
 679         if (ret != 0) {
 680                 if (ret > 0)
 681                         ret = -ENOENT;
 682                 goto out;
 683         }
 684         l = path->nodes[0];
 685         read_extent_buffer(l, &root->root_item,
 686                btrfs_item_ptr_offset(l, path->slots[0]),
 687                sizeof(root->root_item));
 688         memcpy(&root->root_key, location, sizeof(*location));
 689         ret = 0;
 690 out:
 691         btrfs_release_path(root, path);
 692         btrfs_free_path(path);
 693         if (ret) {
 694                 kfree(root);
 695                 return ERR_PTR(ret);
 696         }
 697         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
 698         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
 699                                      blocksize);
 700         BUG_ON(!root->node);
 701 insert:
 702         root->ref_cows = 1;
 703         ret = btrfs_find_highest_inode(root, &highest_inode);
 704         if (ret == 0) {
 705                 root->highest_inode = highest_inode;
 706                 root->last_inode_alloc = highest_inode;
 707         }
 708         return root;
 709 }
 710
 711 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
 712                                         u64 root_objectid)
 713 {
 714         struct btrfs_root *root;
 715
 716         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
 717                 return fs_info->tree_root;
 718         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
 719                 return fs_info->extent_root;
 720
 721         root = radix_tree_lookup(&fs_info->fs_roots_radix,
 722                                  (unsigned long)root_objectid);
 723         return root;
 724 }
 725
 726 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
 727                                               struct btrfs_key *location)
 728 {
 729         struct btrfs_root *root;
 730         int ret;
 731
 732         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
 733                 return fs_info->tree_root;
 734         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
 735                 return fs_info->extent_root;
 736
 737         root = radix_tree_lookup(&fs_info->fs_roots_radix,
 738                                  (unsigned long)location->objectid);
 739         if (root)
 740                 return root;
 741
 742         root = btrfs_read_fs_root_no_radix(fs_info, location);
 743         if (IS_ERR(root))
 744                 return root;
 745         ret = radix_tree_insert(&fs_info->fs_roots_radix,
 746                                 (unsigned long)root->root_key.objectid,
 747                                 root);
 748         if (ret) {
 749                 free_extent_buffer(root->node);
 750                 kfree(root);
 751                 return ERR_PTR(ret);
 752         }
 753         ret = btrfs_find_dead_roots(fs_info->tree_root,
 754                                     root->root_key.objectid, root);
 755         BUG_ON(ret);
 756
 757         return root;
 758 }
 759
 760 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 761                                       struct btrfs_key *location,
 762                                       const char *name, int namelen)
 763 {
 764         struct btrfs_root *root;
 765         int ret;
 766
 767         root = btrfs_read_fs_root_no_name(fs_info, location);
 768         if (!root)
 769                 return NULL;
 770
 771         if (root->in_sysfs)
 772                 return root;
 773
 774         ret = btrfs_set_root_name(root, name, namelen);
 775         if (ret) {
 776                 free_extent_buffer(root->node);
 777                 kfree(root);
 778                 return ERR_PTR(ret);
 779         }
 780
 781         ret = btrfs_sysfs_add_root(root);
 782         if (ret) {
 783                 free_extent_buffer(root->node);
 784                 kfree(root->name);
 785                 kfree(root);
 786                 return ERR_PTR(ret);
 787         }
 788         root->in_sysfs = 1;
 789         return root;
 790 }
 791 #if 0
 792 static int add_hasher(struct btrfs_fs_info *info, char *type) {
 793         struct btrfs_hasher *hasher;
 794
 795         hasher = kmalloc(sizeof(*hasher), GFP_NOFS);
 796         if (!hasher)
 797                 return -ENOMEM;
 798         hasher->hash_tfm = crypto_alloc_hash(type, 0, CRYPTO_ALG_ASYNC);
 799         if (!hasher->hash_tfm) {
 800                 kfree(hasher);
 801                 return -EINVAL;
 802         }
 803         spin_lock(&info->hash_lock);
 804         list_add(&hasher->list, &info->hashers);
 805         spin_unlock(&info->hash_lock);
 806         return 0;
 807 }
 808 #endif
 809
 810 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
 811 {
 812         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
 813         int ret = 0;
 814         struct list_head *cur;
 815         struct btrfs_device *device;
 816         struct backing_dev_info *bdi;
 817
 818         list_for_each(cur, &info->fs_devices->devices) {
 819                 device = list_entry(cur, struct btrfs_device, dev_list);
 820                 bdi = blk_get_backing_dev_info(device->bdev);
 821                 if (bdi && bdi_congested(bdi, bdi_bits)) {
 822                         ret = 1;
 823                         break;
 824                 }
 825         }
 826         return ret;
 827 }
 828
 829 void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
 830 {
 831         struct list_head *cur;
 832         struct btrfs_device *device;
 833         struct btrfs_fs_info *info;
 834
 835         info = (struct btrfs_fs_info *)bdi->unplug_io_data;
 836         list_for_each(cur, &info->fs_devices->devices) {
 837                 device = list_entry(cur, struct btrfs_device, dev_list);
 838                 bdi = blk_get_backing_dev_info(device->bdev);
 839                 if (bdi->unplug_io_fn) {
 840                         bdi->unplug_io_fn(bdi, page);
 841                 }
 842         }
 843 }
 844
 845 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
 846 {
 847         bdi_init(bdi);
 848         bdi->ra_pages   = default_backing_dev_info.ra_pages * 4;
 849         bdi->state              = 0;
 850         bdi->capabilities       = default_backing_dev_info.capabilities;
 851         bdi->unplug_io_fn       = btrfs_unplug_io_fn;
 852         bdi->unplug_io_data     = info;
 853         bdi->congested_fn       = btrfs_congested_fn;
 854         bdi->congested_data     = info;
 855         return 0;
 856 }
 857
 858 static int bio_ready_for_csum(struct bio *bio)
 859 {
 860         u64 length = 0;
 861         u64 buf_len = 0;
 862         u64 start = 0;
 863         struct page *page;
 864         struct extent_io_tree *io_tree = NULL;
 865         struct btrfs_fs_info *info = NULL;
 866         struct bio_vec *bvec;
 867         int i;
 868         int ret;
 869
 870         bio_for_each_segment(bvec, bio, i) {
 871                 page = bvec->bv_page;
 872                 if (page->private == EXTENT_PAGE_PRIVATE) {
 873                         length += bvec->bv_len;
 874                         continue;
 875                 }
 876                 if (!page->private) {
 877                         length += bvec->bv_len;
 878                         continue;
 879                 }
 880                 length = bvec->bv_len;
 881                 buf_len = page->private >> 2;
 882                 start = page_offset(page) + bvec->bv_offset;
 883                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
 884                 info = BTRFS_I(page->mapping->host)->root->fs_info;
 885         }
 886         /* are we fully contained in this bio? */
 887         if (buf_len <= length)
 888                 return 1;
 889
 890         ret = extent_range_uptodate(io_tree, start + length,
 891                                     start + buf_len - 1);
 892         if (ret == 1)
 893                 return ret;
 894         return ret;
 895 }
 896
 897 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
 898 void btrfs_end_io_csum(void *p)
 899 #else
 900 void btrfs_end_io_csum(struct work_struct *work)
 901 #endif
 902 {
 903 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
 904         struct btrfs_fs_info *fs_info = p;
 905 #else
 906         struct btrfs_fs_info *fs_info = container_of(work,
 907                                                      struct btrfs_fs_info,
 908                                                      end_io_work);
 909 #endif
 910         unsigned long flags;
 911         struct end_io_wq *end_io_wq;
 912         struct bio *bio;
 913         struct list_head *next;
 914         int error;
 915         int was_empty;
 916
 917         while(1) {
 918                 spin_lock_irqsave(&fs_info->end_io_work_lock, flags);
 919                 if (list_empty(&fs_info->end_io_work_list)) {
 920                         spin_unlock_irqrestore(&fs_info->end_io_work_lock,
 921                                                flags);
 922                         return;
 923                 }
 924                 next = fs_info->end_io_work_list.next;
 925                 list_del(next);
 926                 spin_unlock_irqrestore(&fs_info->end_io_work_lock, flags);
 927
 928                 end_io_wq = list_entry(next, struct end_io_wq, list);
 929
 930                 bio = end_io_wq->bio;
 931                 if (end_io_wq->metadata && !bio_ready_for_csum(bio)) {
 932                         spin_lock_irqsave(&fs_info->end_io_work_lock, flags);
 933                         was_empty = list_empty(&fs_info->end_io_work_list);
 934                         list_add_tail(&end_io_wq->list,
 935                                       &fs_info->end_io_work_list);
 936                         spin_unlock_irqrestore(&fs_info->end_io_work_lock,
 937                                                flags);
 938                         if (was_empty)
 939                                 return;
 940                         continue;
 941                 }
 942                 error = end_io_wq->error;
 943                 bio->bi_private = end_io_wq->private;
 944                 bio->bi_end_io = end_io_wq->end_io;
 945                 kfree(end_io_wq);
 946                 bio_endio(bio, error);
 947         }
 948 }
 949
 950
 951 struct btrfs_root *open_ctree(struct super_block *sb,
 952                               struct btrfs_fs_devices *fs_devices)
 953 {
 954         u32 sectorsize;
 955         u32 nodesize;
 956         u32 leafsize;
 957         u32 blocksize;
 958         u32 stripesize;
 959         struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
 960                                                  GFP_NOFS);
 961         struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
 962                                                GFP_NOFS);
 963         struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info),
 964                                                 GFP_NOFS);
 965         struct btrfs_root *chunk_root = kmalloc(sizeof(struct btrfs_root),
 966                                                 GFP_NOFS);
 967         struct btrfs_root *dev_root = kmalloc(sizeof(struct btrfs_root),
 968                                               GFP_NOFS);
 969         int ret;
 970         int err = -EINVAL;
 971         struct btrfs_super_block *disk_super;
 972
 973         if (!extent_root || !tree_root || !fs_info) {
 974                 err = -ENOMEM;
 975                 goto fail;
 976         }
 977         end_io_workqueue = create_workqueue("btrfs-end-io");
 978         BUG_ON(!end_io_workqueue);
 979
 980         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
 981         INIT_LIST_HEAD(&fs_info->trans_list);
 982         INIT_LIST_HEAD(&fs_info->dead_roots);
 983         INIT_LIST_HEAD(&fs_info->hashers);
 984         INIT_LIST_HEAD(&fs_info->end_io_work_list);
 985         spin_lock_init(&fs_info->hash_lock);
 986         spin_lock_init(&fs_info->end_io_work_lock);
 987         spin_lock_init(&fs_info->delalloc_lock);
 988         spin_lock_init(&fs_info->new_trans_lock);
 989
 990         init_completion(&fs_info->kobj_unregister);
 991         sb_set_blocksize(sb, 4096);
 992         fs_info->tree_root = tree_root;
 993         fs_info->extent_root = extent_root;
 994         fs_info->chunk_root = chunk_root;
 995         fs_info->dev_root = dev_root;
 996         fs_info->fs_devices = fs_devices;
 997         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
 998         INIT_LIST_HEAD(&fs_info->space_info);
 999         btrfs_mapping_init(&fs_info->mapping_tree);
1000         fs_info->sb = sb;
1001         fs_info->max_extent = (u64)-1;
1002         fs_info->max_inline = 8192 * 1024;
1003         setup_bdi(fs_info, &fs_info->bdi);
1004         fs_info->btree_inode = new_inode(sb);
1005         fs_info->btree_inode->i_ino = 1;
1006         fs_info->btree_inode->i_nlink = 1;
1007         fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
1008         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1009         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1010
1011         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1012                              fs_info->btree_inode->i_mapping,
1013                              GFP_NOFS);
1014         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1015                              GFP_NOFS);
1016
1017         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1018
1019         extent_io_tree_init(&fs_info->free_space_cache,
1020                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1021         extent_io_tree_init(&fs_info->block_group_cache,
1022                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1023         extent_io_tree_init(&fs_info->pinned_extents,
1024                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1025         extent_io_tree_init(&fs_info->pending_del,
1026                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1027         extent_io_tree_init(&fs_info->extent_ins,
1028                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1029         fs_info->do_barriers = 1;
1030
1031         INIT_WORK(&fs_info->end_io_work, btrfs_end_io_csum);
1032 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
1033         INIT_WORK(&fs_info->trans_work, btrfs_transaction_cleaner, fs_info);
1034 #else
1035         INIT_DELAYED_WORK(&fs_info->trans_work, btrfs_transaction_cleaner);
1036 #endif
1037         BTRFS_I(fs_info->btree_inode)->root = tree_root;
1038         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1039                sizeof(struct btrfs_key));
1040         insert_inode_hash(fs_info->btree_inode);
1041         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
1042
1043         mutex_init(&fs_info->trans_mutex);
1044         mutex_init(&fs_info->fs_mutex);
1045
1046 #if 0
1047         ret = add_hasher(fs_info, "crc32c");
1048         if (ret) {
1049                 printk("btrfs: failed hash setup, modprobe cryptomgr?\n");
1050                 err = -ENOMEM;
1051                 goto fail_iput;
1052         }
1053 #endif
1054         __setup_root(4096, 4096, 4096, 4096, tree_root,
1055                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
1056
1057         fs_info->sb_buffer = read_tree_block(tree_root,
1058                                              BTRFS_SUPER_INFO_OFFSET,
1059                                              4096);
1060
1061         if (!fs_info->sb_buffer)
1062                 goto fail_iput;
1063
1064         read_extent_buffer(fs_info->sb_buffer, &fs_info->super_copy, 0,
1065                            sizeof(fs_info->super_copy));
1066
1067         read_extent_buffer(fs_info->sb_buffer, fs_info->fsid,
1068                            (unsigned long)btrfs_super_fsid(fs_info->sb_buffer),
1069                            BTRFS_FSID_SIZE);
1070
1071         disk_super = &fs_info->super_copy;
1072         if (!btrfs_super_root(disk_super))
1073                 goto fail_sb_buffer;
1074
1075         if (btrfs_super_num_devices(disk_super) != fs_devices->num_devices) {
1076                 printk("Btrfs: wanted %llu devices, but found %llu\n",
1077                        (unsigned long long)btrfs_super_num_devices(disk_super),
1078                        (unsigned long long)fs_devices->num_devices);
1079                 goto fail_sb_buffer;
1080         }
1081         nodesize = btrfs_super_nodesize(disk_super);
1082         leafsize = btrfs_super_leafsize(disk_super);
1083         sectorsize = btrfs_super_sectorsize(disk_super);
1084         stripesize = btrfs_super_stripesize(disk_super);
1085         tree_root->nodesize = nodesize;
1086         tree_root->leafsize = leafsize;
1087         tree_root->sectorsize = sectorsize;
1088         tree_root->stripesize = stripesize;
1089         sb_set_blocksize(sb, sectorsize);
1090
1091         i_size_write(fs_info->btree_inode,
1092                      btrfs_super_total_bytes(disk_super));
1093
1094         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1095                     sizeof(disk_super->magic))) {
1096                 printk("btrfs: valid FS not found on %s\n", sb->s_id);
1097                 goto fail_sb_buffer;
1098         }
1099
1100         mutex_lock(&fs_info->fs_mutex);
1101
1102         ret = btrfs_read_sys_array(tree_root);
1103         BUG_ON(ret);
1104
1105         blocksize = btrfs_level_size(tree_root,
1106                                      btrfs_super_chunk_root_level(disk_super));
1107
1108         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1109                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1110
1111         chunk_root->node = read_tree_block(chunk_root,
1112                                            btrfs_super_chunk_root(disk_super),
1113                                            blocksize);
1114         BUG_ON(!chunk_root->node);
1115
1116         ret = btrfs_read_chunk_tree(chunk_root);
1117         BUG_ON(ret);
1118
1119         blocksize = btrfs_level_size(tree_root,
1120                                      btrfs_super_root_level(disk_super));
1121
1122
1123         tree_root->node = read_tree_block(tree_root,
1124                                           btrfs_super_root(disk_super),
1125                                           blocksize);
1126         if (!tree_root->node)
1127                 goto fail_sb_buffer;
1128
1129
1130         ret = find_and_setup_root(tree_root, fs_info,
1131                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
1132         if (ret)
1133                 goto fail_tree_root;
1134         extent_root->track_dirty = 1;
1135
1136         ret = find_and_setup_root(tree_root, fs_info,
1137                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
1138         dev_root->track_dirty = 1;
1139
1140         if (ret)
1141                 goto fail_extent_root;
1142
1143         btrfs_read_block_groups(extent_root);
1144
1145         fs_info->generation = btrfs_super_generation(disk_super) + 1;
1146         fs_info->data_alloc_profile = (u64)-1;
1147         fs_info->metadata_alloc_profile = (u64)-1;
1148         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
1149
1150         mutex_unlock(&fs_info->fs_mutex);
1151         return tree_root;
1152
1153 fail_extent_root:
1154         free_extent_buffer(extent_root->node);
1155 fail_tree_root:
1156         mutex_unlock(&fs_info->fs_mutex);
1157         free_extent_buffer(tree_root->node);
1158 fail_sb_buffer:
1159         free_extent_buffer(fs_info->sb_buffer);
1160         extent_io_tree_empty_lru(&BTRFS_I(fs_info->btree_inode)->io_tree);
1161 fail_iput:
1162         iput(fs_info->btree_inode);
1163 fail:
1164         close_all_devices(fs_info);
1165         kfree(extent_root);
1166         kfree(tree_root);
1167         bdi_destroy(&fs_info->bdi);
1168         kfree(fs_info);
1169         return ERR_PTR(err);
1170 }
1171
1172 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
1173                       *root)
1174 {
1175         int ret;
1176         struct extent_buffer *super = root->fs_info->sb_buffer;
1177         struct inode *btree_inode = root->fs_info->btree_inode;
1178         struct super_block *sb = root->fs_info->sb;
1179
1180         if (!btrfs_test_opt(root, NOBARRIER))
1181                 blkdev_issue_flush(sb->s_bdev, NULL);
1182         set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree, super);
1183         ret = sync_page_range_nolock(btree_inode, btree_inode->i_mapping,
1184                                      super->start, super->len);
1185         if (!btrfs_test_opt(root, NOBARRIER))
1186                 blkdev_issue_flush(sb->s_bdev, NULL);
1187         return ret;
1188 }
1189
1190 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
1191 {
1192         radix_tree_delete(&fs_info->fs_roots_radix,
1193                           (unsigned long)root->root_key.objectid);
1194         if (root->in_sysfs)
1195                 btrfs_sysfs_del_root(root);
1196         if (root->inode)
1197                 iput(root->inode);
1198         if (root->node)
1199                 free_extent_buffer(root->node);
1200         if (root->commit_root)
1201                 free_extent_buffer(root->commit_root);
1202         if (root->name)
1203                 kfree(root->name);
1204         kfree(root);
1205         return 0;
1206 }
1207
1208 static int del_fs_roots(struct btrfs_fs_info *fs_info)
1209 {
1210         int ret;
1211         struct btrfs_root *gang[8];
1212         int i;
1213
1214         while(1) {
1215                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
1216                                              (void **)gang, 0,
1217                                              ARRAY_SIZE(gang));
1218                 if (!ret)
1219                         break;
1220                 for (i = 0; i < ret; i++)
1221                         btrfs_free_fs_root(fs_info, gang[i]);
1222         }
1223         return 0;
1224 }
1225
1226 int close_ctree(struct btrfs_root *root)
1227 {
1228         int ret;
1229         struct btrfs_trans_handle *trans;
1230         struct btrfs_fs_info *fs_info = root->fs_info;
1231
1232         fs_info->closing = 1;
1233         btrfs_transaction_flush_work(root);
1234         mutex_lock(&fs_info->fs_mutex);
1235         btrfs_defrag_dirty_roots(root->fs_info);
1236         trans = btrfs_start_transaction(root, 1);
1237         ret = btrfs_commit_transaction(trans, root);
1238         /* run commit again to  drop the original snapshot */
1239         trans = btrfs_start_transaction(root, 1);
1240         btrfs_commit_transaction(trans, root);
1241         ret = btrfs_write_and_wait_transaction(NULL, root);
1242         BUG_ON(ret);
1243         write_ctree_super(NULL, root);
1244         mutex_unlock(&fs_info->fs_mutex);
1245
1246         if (fs_info->delalloc_bytes) {
1247                 printk("btrfs: at unmount delalloc count %Lu\n",
1248                        fs_info->delalloc_bytes);
1249         }
1250         if (fs_info->extent_root->node)
1251                 free_extent_buffer(fs_info->extent_root->node);
1252
1253         if (fs_info->tree_root->node)
1254                 free_extent_buffer(fs_info->tree_root->node);
1255
1256         if (root->fs_info->chunk_root->node);
1257                 free_extent_buffer(root->fs_info->chunk_root->node);
1258
1259         if (root->fs_info->dev_root->node);
1260                 free_extent_buffer(root->fs_info->dev_root->node);
1261
1262         free_extent_buffer(fs_info->sb_buffer);
1263
1264         btrfs_free_block_groups(root->fs_info);
1265         del_fs_roots(fs_info);
1266
1267         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
1268
1269         extent_io_tree_empty_lru(&fs_info->free_space_cache);
1270         extent_io_tree_empty_lru(&fs_info->block_group_cache);
1271         extent_io_tree_empty_lru(&fs_info->pinned_extents);
1272         extent_io_tree_empty_lru(&fs_info->pending_del);
1273         extent_io_tree_empty_lru(&fs_info->extent_ins);
1274         extent_io_tree_empty_lru(&BTRFS_I(fs_info->btree_inode)->io_tree);
1275
1276         truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
1277         flush_workqueue(end_io_workqueue);
1278         destroy_workqueue(end_io_workqueue);
1279
1280         iput(fs_info->btree_inode);
1281 #if 0
1282         while(!list_empty(&fs_info->hashers)) {
1283                 struct btrfs_hasher *hasher;
1284                 hasher = list_entry(fs_info->hashers.next, struct btrfs_hasher,
1285                                     hashers);
1286                 list_del(&hasher->hashers);
1287                 crypto_free_hash(&fs_info->hash_tfm);
1288                 kfree(hasher);
1289         }
1290 #endif
1291         close_all_devices(fs_info);
1292         btrfs_mapping_tree_free(&fs_info->mapping_tree);
1293         bdi_destroy(&fs_info->bdi);
1294
1295         kfree(fs_info->extent_root);
1296         kfree(fs_info->tree_root);
1297         kfree(fs_info->chunk_root);
1298         kfree(fs_info->dev_root);
1299         return 0;
1300 }
1301
1302 int btrfs_buffer_uptodate(struct extent_buffer *buf)
1303 {
1304         struct inode *btree_inode = buf->first_page->mapping->host;
1305         return extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf);
1306 }
1307
1308 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
1309 {
1310         struct inode *btree_inode = buf->first_page->mapping->host;
1311         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
1312                                           buf);
1313 }
1314
1315 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
1316 {
1317         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1318         u64 transid = btrfs_header_generation(buf);
1319         struct inode *btree_inode = root->fs_info->btree_inode;
1320
1321         if (transid != root->fs_info->generation) {
1322                 printk(KERN_CRIT "transid mismatch buffer %llu, found %Lu running %Lu\n",
1323                         (unsigned long long)buf->start,
1324                         transid, root->fs_info->generation);
1325                 WARN_ON(1);
1326         }
1327         set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree, buf);
1328 }
1329
1330 void btrfs_throttle(struct btrfs_root *root)
1331 {
1332         struct backing_dev_info *bdi;
1333
1334         bdi = root->fs_info->sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
1335         if (root->fs_info->throttles && bdi_write_congested(bdi)) {
1336 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,18)
1337                 congestion_wait(WRITE, HZ/20);
1338 #else
1339                 blk_congestion_wait(WRITE, HZ/20);
1340 #endif
1341         }
1342 }
1343
1344 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
1345 {
1346         balance_dirty_pages_ratelimited_nr(
1347                                    root->fs_info->btree_inode->i_mapping, 1);
1348 }
1349
1350 void btrfs_set_buffer_defrag(struct extent_buffer *buf)
1351 {
1352         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1353         struct inode *btree_inode = root->fs_info->btree_inode;
1354         set_extent_bits(&BTRFS_I(btree_inode)->io_tree, buf->start,
1355                         buf->start + buf->len - 1, EXTENT_DEFRAG, GFP_NOFS);
1356 }
1357
1358 void btrfs_set_buffer_defrag_done(struct extent_buffer *buf)
1359 {
1360         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1361         struct inode *btree_inode = root->fs_info->btree_inode;
1362         set_extent_bits(&BTRFS_I(btree_inode)->io_tree, buf->start,
1363                         buf->start + buf->len - 1, EXTENT_DEFRAG_DONE,
1364                         GFP_NOFS);
1365 }
1366
1367 int btrfs_buffer_defrag(struct extent_buffer *buf)
1368 {
1369         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1370         struct inode *btree_inode = root->fs_info->btree_inode;
1371         return test_range_bit(&BTRFS_I(btree_inode)->io_tree,
1372                      buf->start, buf->start + buf->len - 1, EXTENT_DEFRAG, 0);
1373 }
1374
1375 int btrfs_buffer_defrag_done(struct extent_buffer *buf)
1376 {
1377         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1378         struct inode *btree_inode = root->fs_info->btree_inode;
1379         return test_range_bit(&BTRFS_I(btree_inode)->io_tree,
1380                      buf->start, buf->start + buf->len - 1,
1381                      EXTENT_DEFRAG_DONE, 0);
1382 }
1383
1384 int btrfs_clear_buffer_defrag_done(struct extent_buffer *buf)
1385 {
1386         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1387         struct inode *btree_inode = root->fs_info->btree_inode;
1388         return clear_extent_bits(&BTRFS_I(btree_inode)->io_tree,
1389                      buf->start, buf->start + buf->len - 1,
1390                      EXTENT_DEFRAG_DONE, GFP_NOFS);
1391 }
1392
1393 int btrfs_clear_buffer_defrag(struct extent_buffer *buf)
1394 {
1395         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1396         struct inode *btree_inode = root->fs_info->btree_inode;
1397         return clear_extent_bits(&BTRFS_I(btree_inode)->io_tree,
1398                      buf->start, buf->start + buf->len - 1,
1399                      EXTENT_DEFRAG, GFP_NOFS);
1400 }
1401
1402 int btrfs_read_buffer(struct extent_buffer *buf)
1403 {
1404         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1405         int ret;
1406         ret = btree_read_extent_buffer_pages(root, buf, 0);
1407         if (ret == 0) {
1408                 buf->flags |= EXTENT_UPTODATE;
1409         }
1410         return ret;
1411 }
1412
1413 static struct extent_io_ops btree_extent_io_ops = {
1414         .writepage_io_hook = btree_writepage_io_hook,
1415         .readpage_end_io_hook = btree_readpage_end_io_hook,
1416         .submit_bio_hook = btree_submit_bio_hook,
1417         /* note we're sharing with inode.c for the merge bio hook */
1418         .merge_bio_hook = btrfs_merge_bio_hook,
1419 };