fs/btrfs/disk-io.c

   1 #include <linux/module.h>
   2 #include <linux/fs.h>
   3 #include <linux/blkdev.h>
   4 #include <linux/crypto.h>
   5 #include <linux/scatterlist.h>
   6 #include <linux/swap.h>
   7 #include <linux/radix-tree.h>
   8 #include "ctree.h"
   9 #include "disk-io.h"
  10 #include "transaction.h"
  11 #include "btrfs_inode.h"
  12
  13 struct dev_lookup {
  14         u64 block_start;
  15         u64 num_blocks;
  16         struct block_device *bdev;
  17 };
  18
  19 int btrfs_insert_dev_radix(struct btrfs_root *root,
  20                            struct block_device *bdev,
  21                            u64 block_start,
  22                            u64 num_blocks)
  23 {
  24         struct dev_lookup *lookup;
  25         char b[BDEVNAME_SIZE];
  26         int ret;
  27
  28         lookup = kmalloc(sizeof(*lookup), GFP_NOFS);
  29         if (!lookup)
  30                 return -ENOMEM;
  31         lookup->block_start = block_start;
  32         lookup->num_blocks = num_blocks;
  33         lookup->bdev = bdev;
  34 printk("inserting %s into dev radix %Lu %Lu\n", bdevname(bdev, b), block_start, num_blocks);
  35
  36         ret = radix_tree_insert(&root->fs_info->dev_radix, block_start +
  37                                 num_blocks - 1, lookup);
  38         return ret;
  39 }
  40
  41 u64 bh_blocknr(struct buffer_head *bh)
  42 {
  43         int blkbits = bh->b_page->mapping->host->i_blkbits;
  44         u64 blocknr = bh->b_page->index << (PAGE_CACHE_SHIFT - blkbits);
  45         unsigned long offset;
  46
  47         if (PageHighMem(bh->b_page))
  48                 offset = (unsigned long)bh->b_data;
  49         else
  50                 offset = bh->b_data - (char *)page_address(bh->b_page);
  51         blocknr += offset >> (PAGE_CACHE_SHIFT - blkbits);
  52         return blocknr;
  53 }
  54
  55 static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf)
  56 {
  57         struct btrfs_node *node = btrfs_buffer_node(buf);
  58         if (bh_blocknr(buf) != btrfs_header_blocknr(&node->header)) {
  59                 printk(KERN_CRIT "bh_blocknr(buf) is %Lu, header is %Lu\n",
  60                        bh_blocknr(buf), btrfs_header_blocknr(&node->header));
  61                 BUG();
  62         }
  63         return 0;
  64 }
  65
  66 struct buffer_head *btrfs_find_tree_block(struct btrfs_root *root, u64 blocknr)
  67 {
  68         struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
  69         int blockbits = root->fs_info->sb->s_blocksize_bits;
  70         unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
  71         struct page *page;
  72         struct buffer_head *bh;
  73         struct buffer_head *head;
  74         struct buffer_head *ret = NULL;
  75
  76
  77         page = find_lock_page(mapping, index);
  78         if (!page)
  79                 return NULL;
  80
  81         if (!page_has_buffers(page))
  82                 goto out_unlock;
  83
  84         head = page_buffers(page);
  85         bh = head;
  86         do {
  87                 if (buffer_mapped(bh) && bh_blocknr(bh) == blocknr) {
  88                         ret = bh;
  89                         get_bh(bh);
  90                         goto out_unlock;
  91                 }
  92                 bh = bh->b_this_page;
  93         } while (bh != head);
  94 out_unlock:
  95         unlock_page(page);
  96         if (ret) {
  97                 touch_buffer(ret);
  98         }
  99         page_cache_release(page);
 100         return ret;
 101 }
 102
 103 int btrfs_map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
 104                              u64 logical)
 105 {
 106         struct dev_lookup *lookup[2];
 107
 108         int ret;
 109
 110         root = root->fs_info->dev_root;
 111         ret = radix_tree_gang_lookup(&root->fs_info->dev_radix,
 112                                      (void **)lookup,
 113                                      (unsigned long)logical,
 114                                      ARRAY_SIZE(lookup));
 115         if (ret == 0 || lookup[0]->block_start > logical ||
 116             lookup[0]->block_start + lookup[0]->num_blocks <= logical) {
 117                 ret = -ENOENT;
 118                 goto out;
 119         }
 120         bh->b_bdev = lookup[0]->bdev;
 121         bh->b_blocknr = logical - lookup[0]->block_start;
 122         set_buffer_mapped(bh);
 123         ret = 0;
 124 out:
 125         return ret;
 126 }
 127
 128 struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root,
 129                                                  u64 blocknr)
 130 {
 131         struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
 132         int blockbits = root->fs_info->sb->s_blocksize_bits;
 133         unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
 134         struct page *page;
 135         struct buffer_head *bh;
 136         struct buffer_head *head;
 137         struct buffer_head *ret = NULL;
 138         int err;
 139         u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);
 140
 141         page = grab_cache_page(mapping, index);
 142         if (!page)
 143                 return NULL;
 144
 145         if (!page_has_buffers(page))
 146                 create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0);
 147         head = page_buffers(page);
 148         bh = head;
 149         do {
 150                 if (!buffer_mapped(bh)) {
 151                         err = btrfs_map_bh_to_logical(root, bh, first_block);
 152                         BUG_ON(err);
 153                 }
 154                 if (bh_blocknr(bh) == blocknr) {
 155                         ret = bh;
 156                         get_bh(bh);
 157                         goto out_unlock;
 158                 }
 159                 bh = bh->b_this_page;
 160                 first_block++;
 161         } while (bh != head);
 162 out_unlock:
 163         unlock_page(page);
 164         if (ret)
 165                 touch_buffer(ret);
 166         page_cache_release(page);
 167         return ret;
 168 }
 169
 170 static int btree_get_block(struct inode *inode, sector_t iblock,
 171                            struct buffer_head *bh, int create)
 172 {
 173         int err;
 174         struct btrfs_root *root = BTRFS_I(bh->b_page->mapping->host)->root;
 175         err = btrfs_map_bh_to_logical(root, bh, iblock);
 176         return err;
 177 }
 178
 179 int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
 180                     char *result)
 181 {
 182         struct scatterlist sg;
 183         struct crypto_hash *tfm = root->fs_info->hash_tfm;
 184         struct hash_desc desc;
 185         int ret;
 186
 187         desc.tfm = tfm;
 188         desc.flags = 0;
 189         sg_init_one(&sg, data, len);
 190         spin_lock(&root->fs_info->hash_lock);
 191         ret = crypto_hash_digest(&desc, &sg, 1, result);
 192         spin_unlock(&root->fs_info->hash_lock);
 193         if (ret) {
 194                 printk("sha256 digest failed\n");
 195         }
 196         return ret;
 197 }
 198 static int csum_tree_block(struct btrfs_root *root, struct buffer_head *bh,
 199                            int verify)
 200 {
 201         char result[BTRFS_CSUM_SIZE];
 202         int ret;
 203         struct btrfs_node *node;
 204
 205         ret = btrfs_csum_data(root, bh->b_data + BTRFS_CSUM_SIZE,
 206                               bh->b_size - BTRFS_CSUM_SIZE, result);
 207         if (ret)
 208                 return ret;
 209         if (verify) {
 210                 if (memcmp(bh->b_data, result, BTRFS_CSUM_SIZE)) {
 211                         printk("checksum verify failed on %Lu\n",
 212                                bh_blocknr(bh));
 213                         return 1;
 214                 }
 215         } else {
 216                 node = btrfs_buffer_node(bh);
 217                 memcpy(node->header.csum, result, BTRFS_CSUM_SIZE);
 218         }
 219         return 0;
 220 }
 221
 222 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 223 {
 224         struct buffer_head *bh;
 225         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 226         struct buffer_head *head;
 227         if (!page_has_buffers(page)) {
 228                 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
 229                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
 230         }
 231         head = page_buffers(page);
 232         bh = head;
 233         do {
 234                 if (buffer_dirty(bh))
 235                         csum_tree_block(root, bh, 0);
 236                 bh = bh->b_this_page;
 237         } while (bh != head);
 238         return block_write_full_page(page, btree_get_block, wbc);
 239 }
 240
 241 static int btree_readpage(struct file * file, struct page * page)
 242 {
 243         return block_read_full_page(page, btree_get_block);
 244 }
 245
 246 static struct address_space_operations btree_aops = {
 247         .readpage       = btree_readpage,
 248         .writepage      = btree_writepage,
 249         .sync_page      = block_sync_page,
 250 };
 251
 252 struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr)
 253 {
 254         struct buffer_head *bh = NULL;
 255
 256         bh = btrfs_find_create_tree_block(root, blocknr);
 257         if (!bh)
 258                 return bh;
 259         if (buffer_uptodate(bh))
 260                 goto uptodate;
 261         lock_buffer(bh);
 262         if (!buffer_uptodate(bh)) {
 263                 get_bh(bh);
 264                 bh->b_end_io = end_buffer_read_sync;
 265                 submit_bh(READ, bh);
 266                 wait_on_buffer(bh);
 267                 if (!buffer_uptodate(bh))
 268                         goto fail;
 269                 csum_tree_block(root, bh, 1);
 270         } else {
 271                 unlock_buffer(bh);
 272         }
 273 uptodate:
 274         if (check_tree_block(root, bh))
 275                 BUG();
 276         return bh;
 277 fail:
 278         brelse(bh);
 279         return NULL;
 280 }
 281
 282 int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 283                      struct buffer_head *buf)
 284 {
 285         WARN_ON(atomic_read(&buf->b_count) == 0);
 286         mark_buffer_dirty(buf);
 287         return 0;
 288 }
 289
 290 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 291                      struct buffer_head *buf)
 292 {
 293         WARN_ON(atomic_read(&buf->b_count) == 0);
 294         clear_buffer_dirty(buf);
 295         return 0;
 296 }
 297
 298 static int __setup_root(int blocksize,
 299                         struct btrfs_root *root,
 300                         struct btrfs_fs_info *fs_info,
 301                         u64 objectid)
 302 {
 303         root->node = NULL;
 304         root->inode = NULL;
 305         root->commit_root = NULL;
 306         root->blocksize = blocksize;
 307         root->ref_cows = 0;
 308         root->fs_info = fs_info;
 309         root->objectid = objectid;
 310         root->last_trans = 0;
 311         root->highest_inode = 0;
 312         root->last_inode_alloc = 0;
 313         memset(&root->root_key, 0, sizeof(root->root_key));
 314         memset(&root->root_item, 0, sizeof(root->root_item));
 315         return 0;
 316 }
 317
 318 static int find_and_setup_root(int blocksize,
 319                                struct btrfs_root *tree_root,
 320                                struct btrfs_fs_info *fs_info,
 321                                u64 objectid,
 322                                struct btrfs_root *root)
 323 {
 324         int ret;
 325
 326         __setup_root(blocksize, root, fs_info, objectid);
 327         ret = btrfs_find_last_root(tree_root, objectid,
 328                                    &root->root_item, &root->root_key);
 329         BUG_ON(ret);
 330
 331         root->node = read_tree_block(root,
 332                                      btrfs_root_blocknr(&root->root_item));
 333         BUG_ON(!root->node);
 334         return 0;
 335 }
 336
 337 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 338                                       struct btrfs_key *location)
 339 {
 340         struct btrfs_root *root;
 341         struct btrfs_root *tree_root = fs_info->tree_root;
 342         struct btrfs_path *path;
 343         struct btrfs_leaf *l;
 344         u64 highest_inode;
 345         int ret = 0;
 346
 347 printk("read_fs_root looking for %Lu %Lu %u\n", location->objectid, location->offset, location->flags);
 348         root = radix_tree_lookup(&fs_info->fs_roots_radix,
 349                                  (unsigned long)location->objectid);
 350         if (root) {
 351 printk("found %p in cache\n", root);
 352                 return root;
 353         }
 354         root = kmalloc(sizeof(*root), GFP_NOFS);
 355         if (!root) {
 356 printk("failed1\n");
 357                 return ERR_PTR(-ENOMEM);
 358         }
 359         if (location->offset == (u64)-1) {
 360                 ret = find_and_setup_root(fs_info->sb->s_blocksize,
 361                                           fs_info->tree_root, fs_info,
 362                                           location->objectid, root);
 363                 if (ret) {
 364 printk("failed2\n");
 365                         kfree(root);
 366                         return ERR_PTR(ret);
 367                 }
 368                 goto insert;
 369         }
 370
 371         __setup_root(fs_info->sb->s_blocksize, root, fs_info,
 372                      location->objectid);
 373
 374         path = btrfs_alloc_path();
 375         BUG_ON(!path);
 376         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
 377         if (ret != 0) {
 378 printk("internal search_slot gives us %d\n", ret);
 379                 if (ret > 0)
 380                         ret = -ENOENT;
 381                 goto out;
 382         }
 383         l = btrfs_buffer_leaf(path->nodes[0]);
 384         memcpy(&root->root_item,
 385                btrfs_item_ptr(l, path->slots[0], struct btrfs_root_item),
 386                sizeof(root->root_item));
 387         memcpy(&root->root_key, location, sizeof(*location));
 388         ret = 0;
 389 out:
 390         btrfs_release_path(root, path);
 391         btrfs_free_path(path);
 392         if (ret) {
 393                 kfree(root);
 394                 return ERR_PTR(ret);
 395         }
 396         root->node = read_tree_block(root,
 397                                      btrfs_root_blocknr(&root->root_item));
 398         BUG_ON(!root->node);
 399 insert:
 400 printk("inserting %p\n", root);
 401         root->ref_cows = 1;
 402         ret = radix_tree_insert(&fs_info->fs_roots_radix,
 403                                 (unsigned long)root->root_key.objectid,
 404                                 root);
 405         if (ret) {
 406 printk("radix_tree_insert gives us %d\n", ret);
 407                 brelse(root->node);
 408                 kfree(root);
 409                 return ERR_PTR(ret);
 410         }
 411         ret = btrfs_find_highest_inode(root, &highest_inode);
 412         if (ret == 0) {
 413                 root->highest_inode = highest_inode;
 414                 root->last_inode_alloc = highest_inode;
 415 printk("highest inode is %Lu\n", highest_inode);
 416         }
 417 printk("all worked\n");
 418         return root;
 419 }
 420
 421 int btrfs_open_disk(struct btrfs_root *root, u64 block_start, u64 num_blocks,
 422                     char *filename, int name_len)
 423 {
 424         char *null_filename;
 425         struct block_device *bdev;
 426         int ret;
 427
 428         if (block_start == 0) {
 429 printk("skipping disk with block_start == 0\n");
 430 return 0;
 431         }
 432         null_filename = kmalloc(name_len + 1, GFP_NOFS);
 433         if (!null_filename)
 434                 return -ENOMEM;
 435         memcpy(null_filename, filename, name_len);
 436         null_filename[name_len] = '\0';
 437
 438         bdev = open_bdev_excl(null_filename, O_RDWR, root->fs_info->sb);
 439         if (IS_ERR(bdev)) {
 440                 ret = PTR_ERR(bdev);
 441                 goto out;
 442         }
 443         set_blocksize(bdev, root->fs_info->sb->s_blocksize);
 444         ret = btrfs_insert_dev_radix(root, bdev, block_start, num_blocks);
 445         BUG_ON(ret);
 446         ret = 0;
 447 out:
 448         kfree(null_filename);
 449         return ret;
 450 }
 451
 452 static int read_device_info(struct btrfs_root *root)
 453 {
 454         struct btrfs_path *path;
 455         int ret;
 456         struct btrfs_key key;
 457         struct btrfs_leaf *leaf;
 458         struct btrfs_device_item *dev_item;
 459         int nritems;
 460         int slot;
 461
 462         root = root->fs_info->dev_root;
 463
 464         path = btrfs_alloc_path();
 465         if (!path)
 466                 return -ENOMEM;
 467         key.objectid = 0;
 468         key.offset = 0;
 469         key.flags = 0;
 470         btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
 471
 472         mutex_lock(&root->fs_info->fs_mutex);
 473         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 474         leaf = btrfs_buffer_leaf(path->nodes[0]);
 475         nritems = btrfs_header_nritems(&leaf->header);
 476         while(1) {
 477                 slot = path->slots[0];
 478                 if (slot >= nritems) {
 479                         ret = btrfs_next_leaf(root, path);
 480                         if (ret)
 481                                 break;
 482                         leaf = btrfs_buffer_leaf(path->nodes[0]);
 483                         nritems = btrfs_header_nritems(&leaf->header);
 484                         slot = path->slots[0];
 485                 }
 486                 btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
 487                 if (btrfs_key_type(&key) != BTRFS_DEV_ITEM_KEY) {
 488                         path->slots[0]++;
 489                         continue;
 490                 }
 491                 dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_device_item);
 492 printk("found key %Lu %Lu\n", key.objectid, key.offset);
 493                 ret = btrfs_open_disk(root, key.objectid, key.offset,
 494                                       (char *)(dev_item + 1),
 495                                       btrfs_device_pathlen(dev_item));
 496                 BUG_ON(ret);
 497                 path->slots[0]++;
 498         }
 499         btrfs_free_path(path);
 500         mutex_unlock(&root->fs_info->fs_mutex);
 501         return 0;
 502 }
 503
 504 struct btrfs_root *open_ctree(struct super_block *sb)
 505 {
 506         struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
 507                                                  GFP_NOFS);
 508         struct btrfs_root *dev_root = kmalloc(sizeof(struct btrfs_root),
 509                                                  GFP_NOFS);
 510         struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
 511                                                GFP_NOFS);
 512         struct btrfs_fs_info *fs_info = kmalloc(sizeof(*fs_info),
 513                                                 GFP_NOFS);
 514         int ret;
 515         struct btrfs_super_block *disk_super;
 516         struct dev_lookup *dev_lookup;
 517
 518         init_bit_radix(&fs_info->pinned_radix);
 519         init_bit_radix(&fs_info->pending_del_radix);
 520         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
 521         INIT_RADIX_TREE(&fs_info->dev_radix, GFP_NOFS);
 522         sb_set_blocksize(sb, 4096);
 523         fs_info->running_transaction = NULL;
 524         fs_info->tree_root = tree_root;
 525         fs_info->extent_root = extent_root;
 526         fs_info->dev_root = dev_root;
 527         fs_info->sb = sb;
 528         fs_info->btree_inode = new_inode(sb);
 529         fs_info->btree_inode->i_ino = 1;
 530         fs_info->btree_inode->i_nlink = 1;
 531         fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
 532         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
 533         BTRFS_I(fs_info->btree_inode)->root = tree_root;
 534         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
 535                sizeof(struct btrfs_key));
 536         insert_inode_hash(fs_info->btree_inode);
 537         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
 538         fs_info->hash_tfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC);
 539         spin_lock_init(&fs_info->hash_lock);
 540         if (!fs_info->hash_tfm || IS_ERR(fs_info->hash_tfm)) {
 541                 printk("failed to allocate sha256 hash\n");
 542                 return NULL;
 543         }
 544         mutex_init(&fs_info->trans_mutex);
 545         mutex_init(&fs_info->fs_mutex);
 546         memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
 547         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 548
 549         __setup_root(sb->s_blocksize, dev_root,
 550                      fs_info, BTRFS_DEV_TREE_OBJECTID);
 551
 552         __setup_root(sb->s_blocksize, tree_root,
 553                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
 554
 555         dev_lookup = kmalloc(sizeof(*dev_lookup), GFP_NOFS);
 556         dev_lookup->block_start = 0;
 557         dev_lookup->num_blocks = (u32)-2;
 558         dev_lookup->bdev = sb->s_bdev;
 559         ret = radix_tree_insert(&fs_info->dev_radix, (u32)-2, dev_lookup);
 560         BUG_ON(ret);
 561         fs_info->sb_buffer = read_tree_block(tree_root,
 562                                              BTRFS_SUPER_INFO_OFFSET /
 563                                              sb->s_blocksize);
 564
 565         if (!fs_info->sb_buffer)
 566                 return NULL;
 567         disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
 568         if (!btrfs_super_root(disk_super))
 569                 return NULL;
 570
 571         i_size_write(fs_info->btree_inode,
 572                      btrfs_super_total_blocks(disk_super) <<
 573                      fs_info->btree_inode->i_blkbits);
 574
 575         radix_tree_delete(&fs_info->dev_radix, (u32)-2);
 576         dev_lookup->block_start = btrfs_super_device_block_start(disk_super);
 577         dev_lookup->num_blocks = btrfs_super_device_num_blocks(disk_super);
 578         ret = radix_tree_insert(&fs_info->dev_radix,
 579                                 dev_lookup->block_start +
 580                                 dev_lookup->num_blocks - 1, dev_lookup);
 581         BUG_ON(ret);
 582
 583         fs_info->disk_super = disk_super;
 584
 585         dev_root->node = read_tree_block(tree_root,
 586                                           btrfs_super_device_root(disk_super));
 587
 588         ret = read_device_info(dev_root);
 589         BUG_ON(ret);
 590
 591         tree_root->node = read_tree_block(tree_root,
 592                                           btrfs_super_root(disk_super));
 593         BUG_ON(!tree_root->node);
 594
 595         mutex_lock(&fs_info->fs_mutex);
 596         ret = find_and_setup_root(sb->s_blocksize, tree_root, fs_info,
 597                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
 598         BUG_ON(ret);
 599
 600         fs_info->generation = btrfs_super_generation(disk_super) + 1;
 601         memset(&fs_info->kobj, 0, sizeof(fs_info->kobj));
 602         kobj_set_kset_s(fs_info, btrfs_subsys);
 603         kobject_set_name(&fs_info->kobj, "%s", sb->s_id);
 604         kobject_register(&fs_info->kobj);
 605         mutex_unlock(&fs_info->fs_mutex);
 606         return tree_root;
 607 }
 608
 609 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 610                       *root)
 611 {
 612         struct buffer_head *bh = root->fs_info->sb_buffer;
 613
 614         btrfs_set_super_root(root->fs_info->disk_super,
 615                              bh_blocknr(root->fs_info->tree_root->node));
 616         lock_buffer(bh);
 617         WARN_ON(atomic_read(&bh->b_count) < 1);
 618         clear_buffer_dirty(bh);
 619         csum_tree_block(root, bh, 0);
 620         bh->b_end_io = end_buffer_write_sync;
 621         get_bh(bh);
 622         submit_bh(WRITE, bh);
 623         wait_on_buffer(bh);
 624         if (!buffer_uptodate(bh)) {
 625                 WARN_ON(1);
 626                 return -EIO;
 627         }
 628         return 0;
 629 }
 630
 631 static int free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
 632 {
 633         radix_tree_delete(&fs_info->fs_roots_radix,
 634                           (unsigned long)root->root_key.objectid);
 635         if (root->inode)
 636                 iput(root->inode);
 637         if (root->node)
 638                 brelse(root->node);
 639         if (root->commit_root)
 640                 brelse(root->commit_root);
 641         kfree(root);
 642         return 0;
 643 }
 644
 645 int del_fs_roots(struct btrfs_fs_info *fs_info)
 646 {
 647         int ret;
 648         struct btrfs_root *gang[8];
 649         int i;
 650
 651         while(1) {
 652                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
 653                                              (void **)gang, 0,
 654                                              ARRAY_SIZE(gang));
 655                 if (!ret)
 656                         break;
 657                 for (i = 0; i < ret; i++)
 658                         free_fs_root(fs_info, gang[i]);
 659         }
 660         return 0;
 661 }
 662 static int free_dev_radix(struct btrfs_fs_info *fs_info)
 663 {
 664         struct dev_lookup *lookup[8];
 665         struct block_device *super_bdev = fs_info->sb->s_bdev;
 666         int ret;
 667         int i;
 668         while(1) {
 669                 ret = radix_tree_gang_lookup(&fs_info->dev_radix,
 670                                              (void **)lookup, 0,
 671                                              ARRAY_SIZE(lookup));
 672                 if (!ret)
 673                         break;
 674                 for (i = 0; i < ret; i++) {
 675                         if (lookup[i]->bdev != super_bdev)
 676                                 close_bdev_excl(lookup[i]->bdev);
 677                         radix_tree_delete(&fs_info->dev_radix,
 678                                           lookup[i]->block_start +
 679                                           lookup[i]->num_blocks - 1);
 680                         kfree(lookup[i]);
 681                 }
 682         }
 683         return 0;
 684 }
 685
 686 int close_ctree(struct btrfs_root *root)
 687 {
 688         int ret;
 689         struct btrfs_trans_handle *trans;
 690         struct btrfs_fs_info *fs_info = root->fs_info;
 691
 692         mutex_lock(&fs_info->fs_mutex);
 693         trans = btrfs_start_transaction(root, 1);
 694         btrfs_commit_transaction(trans, root);
 695         /* run commit again to  drop the original snapshot */
 696         trans = btrfs_start_transaction(root, 1);
 697         btrfs_commit_transaction(trans, root);
 698         ret = btrfs_write_and_wait_transaction(NULL, root);
 699         BUG_ON(ret);
 700         write_ctree_super(NULL, root);
 701         mutex_unlock(&fs_info->fs_mutex);
 702
 703         if (fs_info->extent_root->node)
 704                 btrfs_block_release(fs_info->extent_root,
 705                                     fs_info->extent_root->node);
 706         if (fs_info->dev_root->node)
 707                 btrfs_block_release(fs_info->dev_root,
 708                                     fs_info->dev_root->node);
 709         if (fs_info->tree_root->node)
 710                 btrfs_block_release(fs_info->tree_root,
 711                                     fs_info->tree_root->node);
 712         btrfs_block_release(root, fs_info->sb_buffer);
 713         crypto_free_hash(fs_info->hash_tfm);
 714         truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
 715         iput(fs_info->btree_inode);
 716
 717         free_dev_radix(fs_info);
 718         del_fs_roots(fs_info);
 719         kfree(fs_info->extent_root);
 720         kfree(fs_info->tree_root);
 721         kobject_unregister(&fs_info->kobj);
 722         return 0;
 723 }
 724
 725 void btrfs_block_release(struct btrfs_root *root, struct buffer_head *buf)
 726 {
 727         brelse(buf);
 728 }
 729