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         u64 device_id;
  17         struct block_device *bdev;
  18 };
  19
  20 int btrfs_insert_dev_radix(struct btrfs_root *root,
  21                            struct block_device *bdev,
  22                            u64 device_id,
  23                            u64 block_start,
  24                            u64 num_blocks)
  25 {
  26         struct dev_lookup *lookup;
  27         int ret;
  28
  29         lookup = kmalloc(sizeof(*lookup), GFP_NOFS);
  30         if (!lookup)
  31                 return -ENOMEM;
  32         lookup->block_start = block_start;
  33         lookup->num_blocks = num_blocks;
  34         lookup->bdev = bdev;
  35         lookup->device_id = device_id;
  36
  37         ret = radix_tree_insert(&root->fs_info->dev_radix, block_start +
  38                                 num_blocks - 1, lookup);
  39         return ret;
  40 }
  41
  42 u64 bh_blocknr(struct buffer_head *bh)
  43 {
  44         int blkbits = bh->b_page->mapping->host->i_blkbits;
  45         u64 blocknr = bh->b_page->index << (PAGE_CACHE_SHIFT - blkbits);
  46         unsigned long offset;
  47
  48         if (PageHighMem(bh->b_page))
  49                 offset = (unsigned long)bh->b_data;
  50         else
  51                 offset = bh->b_data - (char *)page_address(bh->b_page);
  52         blocknr += offset >> (PAGE_CACHE_SHIFT - blkbits);
  53         return blocknr;
  54 }
  55
  56 static int check_tree_block(struct btrfs_root *root, struct buffer_head *buf)
  57 {
  58         struct btrfs_node *node = btrfs_buffer_node(buf);
  59         if (bh_blocknr(buf) != btrfs_header_blocknr(&node->header)) {
  60                 printk(KERN_CRIT "bh_blocknr(buf) is %Lu, header is %Lu\n",
  61                        bh_blocknr(buf), btrfs_header_blocknr(&node->header));
  62                 BUG();
  63         }
  64         return 0;
  65 }
  66
  67 struct buffer_head *btrfs_find_tree_block(struct btrfs_root *root, u64 blocknr)
  68 {
  69         struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
  70         int blockbits = root->fs_info->sb->s_blocksize_bits;
  71         unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
  72         struct page *page;
  73         struct buffer_head *bh;
  74         struct buffer_head *head;
  75         struct buffer_head *ret = NULL;
  76
  77
  78         page = find_lock_page(mapping, index);
  79         if (!page)
  80                 return NULL;
  81
  82         if (!page_has_buffers(page))
  83                 goto out_unlock;
  84
  85         head = page_buffers(page);
  86         bh = head;
  87         do {
  88                 if (buffer_mapped(bh) && bh_blocknr(bh) == blocknr) {
  89                         ret = bh;
  90                         get_bh(bh);
  91                         goto out_unlock;
  92                 }
  93                 bh = bh->b_this_page;
  94         } while (bh != head);
  95 out_unlock:
  96         unlock_page(page);
  97         if (ret) {
  98                 touch_buffer(ret);
  99         }
 100         page_cache_release(page);
 101         return ret;
 102 }
 103
 104 int btrfs_map_bh_to_logical(struct btrfs_root *root, struct buffer_head *bh,
 105                              u64 logical)
 106 {
 107         struct dev_lookup *lookup[2];
 108
 109         int ret;
 110
 111         root = root->fs_info->dev_root;
 112         ret = radix_tree_gang_lookup(&root->fs_info->dev_radix,
 113                                      (void **)lookup,
 114                                      (unsigned long)logical,
 115                                      ARRAY_SIZE(lookup));
 116         if (ret == 0 || lookup[0]->block_start > logical ||
 117             lookup[0]->block_start + lookup[0]->num_blocks <= logical) {
 118                 ret = -ENOENT;
 119                 goto out;
 120         }
 121         bh->b_bdev = lookup[0]->bdev;
 122         bh->b_blocknr = logical - lookup[0]->block_start;
 123         set_buffer_mapped(bh);
 124         ret = 0;
 125 out:
 126         return ret;
 127 }
 128
 129 struct buffer_head *btrfs_find_create_tree_block(struct btrfs_root *root,
 130                                                  u64 blocknr)
 131 {
 132         struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
 133         int blockbits = root->fs_info->sb->s_blocksize_bits;
 134         unsigned long index = blocknr >> (PAGE_CACHE_SHIFT - blockbits);
 135         struct page *page;
 136         struct buffer_head *bh;
 137         struct buffer_head *head;
 138         struct buffer_head *ret = NULL;
 139         int err;
 140         u64 first_block = index << (PAGE_CACHE_SHIFT - blockbits);
 141
 142         page = grab_cache_page(mapping, index);
 143         if (!page)
 144                 return NULL;
 145
 146         if (!page_has_buffers(page))
 147                 create_empty_buffers(page, root->fs_info->sb->s_blocksize, 0);
 148         head = page_buffers(page);
 149         bh = head;
 150         do {
 151                 if (!buffer_mapped(bh)) {
 152                         err = btrfs_map_bh_to_logical(root, bh, first_block);
 153                         BUG_ON(err);
 154                 }
 155                 if (bh_blocknr(bh) == blocknr) {
 156                         ret = bh;
 157                         get_bh(bh);
 158                         goto out_unlock;
 159                 }
 160                 bh = bh->b_this_page;
 161                 first_block++;
 162         } while (bh != head);
 163 out_unlock:
 164         unlock_page(page);
 165         if (ret)
 166                 touch_buffer(ret);
 167         page_cache_release(page);
 168         return ret;
 169 }
 170
 171 static int btree_get_block(struct inode *inode, sector_t iblock,
 172                            struct buffer_head *bh, int create)
 173 {
 174         int err;
 175         struct btrfs_root *root = BTRFS_I(bh->b_page->mapping->host)->root;
 176         err = btrfs_map_bh_to_logical(root, bh, iblock);
 177         return err;
 178 }
 179
 180 int btrfs_csum_data(struct btrfs_root * root, char *data, size_t len,
 181                     char *result)
 182 {
 183         struct scatterlist sg;
 184         struct crypto_hash *tfm = root->fs_info->hash_tfm;
 185         struct hash_desc desc;
 186         int ret;
 187
 188         desc.tfm = tfm;
 189         desc.flags = 0;
 190         sg_init_one(&sg, data, len);
 191         spin_lock(&root->fs_info->hash_lock);
 192         ret = crypto_hash_digest(&desc, &sg, 1, result);
 193         spin_unlock(&root->fs_info->hash_lock);
 194         if (ret) {
 195                 printk("sha256 digest failed\n");
 196         }
 197         return ret;
 198 }
 199 static int csum_tree_block(struct btrfs_root *root, struct buffer_head *bh,
 200                            int verify)
 201 {
 202         char result[BTRFS_CSUM_SIZE];
 203         int ret;
 204         struct btrfs_node *node;
 205
 206         ret = btrfs_csum_data(root, bh->b_data + BTRFS_CSUM_SIZE,
 207                               bh->b_size - BTRFS_CSUM_SIZE, result);
 208         if (ret)
 209                 return ret;
 210         if (verify) {
 211                 if (memcmp(bh->b_data, result, BTRFS_CSUM_SIZE)) {
 212                         printk("checksum verify failed on %Lu\n",
 213                                bh_blocknr(bh));
 214                         return 1;
 215                 }
 216         } else {
 217                 node = btrfs_buffer_node(bh);
 218                 memcpy(node->header.csum, result, BTRFS_CSUM_SIZE);
 219         }
 220         return 0;
 221 }
 222
 223 static int btree_writepage(struct page *page, struct writeback_control *wbc)
 224 {
 225         struct buffer_head *bh;
 226         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
 227         struct buffer_head *head;
 228         if (!page_has_buffers(page)) {
 229                 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
 230                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
 231         }
 232         head = page_buffers(page);
 233         bh = head;
 234         do {
 235                 if (buffer_dirty(bh))
 236                         csum_tree_block(root, bh, 0);
 237                 bh = bh->b_this_page;
 238         } while (bh != head);
 239         return block_write_full_page(page, btree_get_block, wbc);
 240 }
 241
 242 static int btree_readpage(struct file * file, struct page * page)
 243 {
 244         return block_read_full_page(page, btree_get_block);
 245 }
 246
 247 static struct address_space_operations btree_aops = {
 248         .readpage       = btree_readpage,
 249         .writepage      = btree_writepage,
 250         .sync_page      = block_sync_page,
 251 };
 252
 253 struct buffer_head *read_tree_block(struct btrfs_root *root, u64 blocknr)
 254 {
 255         struct buffer_head *bh = NULL;
 256
 257         bh = btrfs_find_create_tree_block(root, blocknr);
 258         if (!bh)
 259                 return bh;
 260         if (buffer_uptodate(bh))
 261                 goto uptodate;
 262         lock_buffer(bh);
 263         if (!buffer_uptodate(bh)) {
 264                 get_bh(bh);
 265                 bh->b_end_io = end_buffer_read_sync;
 266                 submit_bh(READ, bh);
 267                 wait_on_buffer(bh);
 268                 if (!buffer_uptodate(bh))
 269                         goto fail;
 270                 csum_tree_block(root, bh, 1);
 271         } else {
 272                 unlock_buffer(bh);
 273         }
 274 uptodate:
 275         if (check_tree_block(root, bh))
 276                 BUG();
 277         return bh;
 278 fail:
 279         brelse(bh);
 280         return NULL;
 281 }
 282
 283 int dirty_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 284                      struct buffer_head *buf)
 285 {
 286         WARN_ON(atomic_read(&buf->b_count) == 0);
 287         mark_buffer_dirty(buf);
 288         return 0;
 289 }
 290
 291 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 292                      struct buffer_head *buf)
 293 {
 294         WARN_ON(atomic_read(&buf->b_count) == 0);
 295         clear_buffer_dirty(buf);
 296         return 0;
 297 }
 298
 299 static int __setup_root(int blocksize,
 300                         struct btrfs_root *root,
 301                         struct btrfs_fs_info *fs_info,
 302                         u64 objectid)
 303 {
 304         root->node = NULL;
 305         root->inode = NULL;
 306         root->commit_root = NULL;
 307         root->blocksize = blocksize;
 308         root->ref_cows = 0;
 309         root->fs_info = fs_info;
 310         root->objectid = objectid;
 311         root->last_trans = 0;
 312         root->highest_inode = 0;
 313         root->last_inode_alloc = 0;
 314         memset(&root->root_key, 0, sizeof(root->root_key));
 315         memset(&root->root_item, 0, sizeof(root->root_item));
 316         return 0;
 317 }
 318
 319 static int find_and_setup_root(int blocksize,
 320                                struct btrfs_root *tree_root,
 321                                struct btrfs_fs_info *fs_info,
 322                                u64 objectid,
 323                                struct btrfs_root *root)
 324 {
 325         int ret;
 326
 327         __setup_root(blocksize, root, fs_info, objectid);
 328         ret = btrfs_find_last_root(tree_root, objectid,
 329                                    &root->root_item, &root->root_key);
 330         BUG_ON(ret);
 331
 332         root->node = read_tree_block(root,
 333                                      btrfs_root_blocknr(&root->root_item));
 334         BUG_ON(!root->node);
 335         return 0;
 336 }
 337
 338 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
 339                                       struct btrfs_key *location)
 340 {
 341         struct btrfs_root *root;
 342         struct btrfs_root *tree_root = fs_info->tree_root;
 343         struct btrfs_path *path;
 344         struct btrfs_leaf *l;
 345         u64 highest_inode;
 346         int ret = 0;
 347
 348 printk("read_fs_root looking for %Lu %Lu %u\n", location->objectid, location->offset, location->flags);
 349         root = radix_tree_lookup(&fs_info->fs_roots_radix,
 350                                  (unsigned long)location->objectid);
 351         if (root) {
 352 printk("found %p in cache\n", root);
 353                 return root;
 354         }
 355         root = kmalloc(sizeof(*root), GFP_NOFS);
 356         if (!root) {
 357 printk("failed1\n");
 358                 return ERR_PTR(-ENOMEM);
 359         }
 360         if (location->offset == (u64)-1) {
 361                 ret = find_and_setup_root(fs_info->sb->s_blocksize,
 362                                           fs_info->tree_root, fs_info,
 363                                           location->objectid, root);
 364                 if (ret) {
 365 printk("failed2\n");
 366                         kfree(root);
 367                         return ERR_PTR(ret);
 368                 }
 369                 goto insert;
 370         }
 371
 372         __setup_root(fs_info->sb->s_blocksize, root, fs_info,
 373                      location->objectid);
 374
 375         path = btrfs_alloc_path();
 376         BUG_ON(!path);
 377         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
 378         if (ret != 0) {
 379 printk("internal search_slot gives us %d\n", ret);
 380                 if (ret > 0)
 381                         ret = -ENOENT;
 382                 goto out;
 383         }
 384         l = btrfs_buffer_leaf(path->nodes[0]);
 385         memcpy(&root->root_item,
 386                btrfs_item_ptr(l, path->slots[0], struct btrfs_root_item),
 387                sizeof(root->root_item));
 388         memcpy(&root->root_key, location, sizeof(*location));
 389         ret = 0;
 390 out:
 391         btrfs_release_path(root, path);
 392         btrfs_free_path(path);
 393         if (ret) {
 394                 kfree(root);
 395                 return ERR_PTR(ret);
 396         }
 397         root->node = read_tree_block(root,
 398                                      btrfs_root_blocknr(&root->root_item));
 399         BUG_ON(!root->node);
 400 insert:
 401 printk("inserting %p\n", root);
 402         root->ref_cows = 1;
 403         ret = radix_tree_insert(&fs_info->fs_roots_radix,
 404                                 (unsigned long)root->root_key.objectid,
 405                                 root);
 406         if (ret) {
 407 printk("radix_tree_insert gives us %d\n", ret);
 408                 brelse(root->node);
 409                 kfree(root);
 410                 return ERR_PTR(ret);
 411         }
 412         ret = btrfs_find_highest_inode(root, &highest_inode);
 413         if (ret == 0) {
 414                 root->highest_inode = highest_inode;
 415                 root->last_inode_alloc = highest_inode;
 416 printk("highest inode is %Lu\n", highest_inode);
 417         }
 418 printk("all worked\n");
 419         return root;
 420 }
 421
 422 static int btrfs_open_disk(struct btrfs_root *root, u64 device_id,
 423                            u64 block_start, u64 num_blocks,
 424                            char *filename, int name_len)
 425 {
 426         char *null_filename;
 427         struct block_device *bdev;
 428         int ret;
 429
 430         null_filename = kmalloc(name_len + 1, GFP_NOFS);
 431         if (!null_filename)
 432                 return -ENOMEM;
 433         memcpy(null_filename, filename, name_len);
 434         null_filename[name_len] = '\0';
 435
 436         bdev = open_bdev_excl(null_filename, O_RDWR, root->fs_info->sb);
 437         if (IS_ERR(bdev)) {
 438                 ret = PTR_ERR(bdev);
 439                 goto out;
 440         }
 441         set_blocksize(bdev, root->fs_info->sb->s_blocksize);
 442         ret = btrfs_insert_dev_radix(root, bdev, device_id,
 443                                      block_start, num_blocks);
 444         BUG_ON(ret);
 445         ret = 0;
 446 out:
 447         kfree(null_filename);
 448         return ret;
 449 }
 450
 451 static int read_device_info(struct btrfs_root *root)
 452 {
 453         struct btrfs_path *path;
 454         int ret;
 455         struct btrfs_key key;
 456         struct btrfs_leaf *leaf;
 457         struct btrfs_device_item *dev_item;
 458         int nritems;
 459         int slot;
 460
 461         root = root->fs_info->dev_root;
 462
 463         path = btrfs_alloc_path();
 464         if (!path)
 465                 return -ENOMEM;
 466         key.objectid = 0;
 467         key.offset = 0;
 468         key.flags = 0;
 469         btrfs_set_key_type(&key, BTRFS_DEV_ITEM_KEY);
 470
 471         mutex_lock(&root->fs_info->fs_mutex);
 472         ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
 473         leaf = btrfs_buffer_leaf(path->nodes[0]);
 474         nritems = btrfs_header_nritems(&leaf->header);
 475         while(1) {
 476                 slot = path->slots[0];
 477                 if (slot >= nritems) {
 478                         ret = btrfs_next_leaf(root, path);
 479                         if (ret)
 480                                 break;
 481                         leaf = btrfs_buffer_leaf(path->nodes[0]);
 482                         nritems = btrfs_header_nritems(&leaf->header);
 483                         slot = path->slots[0];
 484                 }
 485                 btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key);
 486                 if (btrfs_key_type(&key) != BTRFS_DEV_ITEM_KEY) {
 487                         path->slots[0]++;
 488                         continue;
 489                 }
 490                 dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_device_item);
 491 printk("found key %Lu %Lu\n", key.objectid, key.offset);
 492                 if (btrfs_device_id(dev_item) !=
 493                     btrfs_super_device_id(root->fs_info->disk_super)) {
 494                         ret = btrfs_open_disk(root, btrfs_device_id(dev_item),
 495                                               key.objectid, key.offset,
 496                                               (char *)(dev_item + 1),
 497                                               btrfs_device_pathlen(dev_item));
 498                         BUG_ON(ret);
 499                 }
 500                 path->slots[0]++;
 501         }
 502         btrfs_free_path(path);
 503         mutex_unlock(&root->fs_info->fs_mutex);
 504         return 0;
 505 }
 506
 507 struct btrfs_root *open_ctree(struct super_block *sb)
 508 {
 509         struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
 510                                                  GFP_NOFS);
 511         struct btrfs_root *dev_root = kmalloc(sizeof(struct btrfs_root),
 512                                                  GFP_NOFS);
 513         struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
 514                                                GFP_NOFS);
 515         struct btrfs_fs_info *fs_info = kmalloc(sizeof(*fs_info),
 516                                                 GFP_NOFS);
 517         int ret;
 518         struct btrfs_super_block *disk_super;
 519         struct dev_lookup *dev_lookup;
 520
 521         init_bit_radix(&fs_info->pinned_radix);
 522         init_bit_radix(&fs_info->pending_del_radix);
 523         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
 524         INIT_RADIX_TREE(&fs_info->dev_radix, GFP_NOFS);
 525         sb_set_blocksize(sb, 4096);
 526         fs_info->running_transaction = NULL;
 527         fs_info->tree_root = tree_root;
 528         fs_info->extent_root = extent_root;
 529         fs_info->dev_root = dev_root;
 530         fs_info->sb = sb;
 531         fs_info->btree_inode = new_inode(sb);
 532         fs_info->btree_inode->i_ino = 1;
 533         fs_info->btree_inode->i_nlink = 1;
 534         fs_info->btree_inode->i_size = sb->s_bdev->bd_inode->i_size;
 535         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
 536         BTRFS_I(fs_info->btree_inode)->root = tree_root;
 537         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
 538                sizeof(struct btrfs_key));
 539         insert_inode_hash(fs_info->btree_inode);
 540         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
 541         fs_info->hash_tfm = crypto_alloc_hash("sha256", 0, CRYPTO_ALG_ASYNC);
 542         spin_lock_init(&fs_info->hash_lock);
 543         if (!fs_info->hash_tfm || IS_ERR(fs_info->hash_tfm)) {
 544                 printk("failed to allocate sha256 hash\n");
 545                 return NULL;
 546         }
 547         mutex_init(&fs_info->trans_mutex);
 548         mutex_init(&fs_info->fs_mutex);
 549         memset(&fs_info->current_insert, 0, sizeof(fs_info->current_insert));
 550         memset(&fs_info->last_insert, 0, sizeof(fs_info->last_insert));
 551
 552         __setup_root(sb->s_blocksize, dev_root,
 553                      fs_info, BTRFS_DEV_TREE_OBJECTID);
 554
 555         __setup_root(sb->s_blocksize, tree_root,
 556                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
 557
 558         dev_lookup = kmalloc(sizeof(*dev_lookup), GFP_NOFS);
 559         dev_lookup->block_start = 0;
 560         dev_lookup->num_blocks = (u32)-2;
 561         dev_lookup->bdev = sb->s_bdev;
 562         dev_lookup->device_id = 0;
 563         ret = radix_tree_insert(&fs_info->dev_radix, (u32)-2, dev_lookup);
 564         BUG_ON(ret);
 565         fs_info->sb_buffer = read_tree_block(tree_root,
 566                                              BTRFS_SUPER_INFO_OFFSET /
 567                                              sb->s_blocksize);
 568
 569         if (!fs_info->sb_buffer)
 570                 return NULL;
 571         disk_super = (struct btrfs_super_block *)fs_info->sb_buffer->b_data;
 572         if (!btrfs_super_root(disk_super))
 573                 return NULL;
 574
 575         i_size_write(fs_info->btree_inode,
 576                      btrfs_super_total_blocks(disk_super) <<
 577                      fs_info->btree_inode->i_blkbits);
 578
 579         radix_tree_delete(&fs_info->dev_radix, (u32)-2);
 580         dev_lookup->block_start = btrfs_super_device_block_start(disk_super);
 581         dev_lookup->num_blocks = btrfs_super_device_num_blocks(disk_super);
 582         dev_lookup->device_id = btrfs_super_device_id(disk_super);
 583
 584         ret = radix_tree_insert(&fs_info->dev_radix,
 585                                 dev_lookup->block_start +
 586                                 dev_lookup->num_blocks - 1, dev_lookup);
 587         BUG_ON(ret);
 588
 589         fs_info->disk_super = disk_super;
 590
 591         dev_root->node = read_tree_block(tree_root,
 592                                           btrfs_super_device_root(disk_super));
 593
 594         ret = read_device_info(dev_root);
 595         BUG_ON(ret);
 596
 597         tree_root->node = read_tree_block(tree_root,
 598                                           btrfs_super_root(disk_super));
 599         BUG_ON(!tree_root->node);
 600
 601         mutex_lock(&fs_info->fs_mutex);
 602         ret = find_and_setup_root(sb->s_blocksize, tree_root, fs_info,
 603                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
 604         BUG_ON(ret);
 605
 606         fs_info->generation = btrfs_super_generation(disk_super) + 1;
 607         memset(&fs_info->kobj, 0, sizeof(fs_info->kobj));
 608         kobj_set_kset_s(fs_info, btrfs_subsys);
 609         kobject_set_name(&fs_info->kobj, "%s", sb->s_id);
 610         kobject_register(&fs_info->kobj);
 611         mutex_unlock(&fs_info->fs_mutex);
 612         return tree_root;
 613 }
 614
 615 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
 616                       *root)
 617 {
 618         struct buffer_head *bh = root->fs_info->sb_buffer;
 619
 620         btrfs_set_super_root(root->fs_info->disk_super,
 621                              bh_blocknr(root->fs_info->tree_root->node));
 622         lock_buffer(bh);
 623         WARN_ON(atomic_read(&bh->b_count) < 1);
 624         clear_buffer_dirty(bh);
 625         csum_tree_block(root, bh, 0);
 626         bh->b_end_io = end_buffer_write_sync;
 627         get_bh(bh);
 628         submit_bh(WRITE, bh);
 629         wait_on_buffer(bh);
 630         if (!buffer_uptodate(bh)) {
 631                 WARN_ON(1);
 632                 return -EIO;
 633         }
 634         return 0;
 635 }
 636
 637 static int free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
 638 {
 639         radix_tree_delete(&fs_info->fs_roots_radix,
 640                           (unsigned long)root->root_key.objectid);
 641         if (root->inode)
 642                 iput(root->inode);
 643         if (root->node)
 644                 brelse(root->node);
 645         if (root->commit_root)
 646                 brelse(root->commit_root);
 647         kfree(root);
 648         return 0;
 649 }
 650
 651 int del_fs_roots(struct btrfs_fs_info *fs_info)
 652 {
 653         int ret;
 654         struct btrfs_root *gang[8];
 655         int i;
 656
 657         while(1) {
 658                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
 659                                              (void **)gang, 0,
 660                                              ARRAY_SIZE(gang));
 661                 if (!ret)
 662                         break;
 663                 for (i = 0; i < ret; i++)
 664                         free_fs_root(fs_info, gang[i]);
 665         }
 666         return 0;
 667 }
 668
 669 static int free_dev_radix(struct btrfs_fs_info *fs_info)
 670 {
 671         struct dev_lookup *lookup[8];
 672         struct block_device *super_bdev = fs_info->sb->s_bdev;
 673         int ret;
 674         int i;
 675         while(1) {
 676                 ret = radix_tree_gang_lookup(&fs_info->dev_radix,
 677                                              (void **)lookup, 0,
 678                                              ARRAY_SIZE(lookup));
 679                 if (!ret)
 680                         break;
 681                 for (i = 0; i < ret; i++) {
 682                         if (lookup[i]->bdev != super_bdev)
 683                                 close_bdev_excl(lookup[i]->bdev);
 684                         radix_tree_delete(&fs_info->dev_radix,
 685                                           lookup[i]->block_start +
 686                                           lookup[i]->num_blocks - 1);
 687                         kfree(lookup[i]);
 688                 }
 689         }
 690         return 0;
 691 }
 692
 693 int close_ctree(struct btrfs_root *root)
 694 {
 695         int ret;
 696         struct btrfs_trans_handle *trans;
 697         struct btrfs_fs_info *fs_info = root->fs_info;
 698
 699         mutex_lock(&fs_info->fs_mutex);
 700         trans = btrfs_start_transaction(root, 1);
 701         btrfs_commit_transaction(trans, root);
 702         /* run commit again to  drop the original snapshot */
 703         trans = btrfs_start_transaction(root, 1);
 704         btrfs_commit_transaction(trans, root);
 705         ret = btrfs_write_and_wait_transaction(NULL, root);
 706         BUG_ON(ret);
 707         write_ctree_super(NULL, root);
 708         mutex_unlock(&fs_info->fs_mutex);
 709
 710         if (fs_info->extent_root->node)
 711                 btrfs_block_release(fs_info->extent_root,
 712                                     fs_info->extent_root->node);
 713         if (fs_info->dev_root->node)
 714                 btrfs_block_release(fs_info->dev_root,
 715                                     fs_info->dev_root->node);
 716         if (fs_info->tree_root->node)
 717                 btrfs_block_release(fs_info->tree_root,
 718                                     fs_info->tree_root->node);
 719         btrfs_block_release(root, fs_info->sb_buffer);
 720         crypto_free_hash(fs_info->hash_tfm);
 721         truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
 722         iput(fs_info->btree_inode);
 723
 724         free_dev_radix(fs_info);
 725         del_fs_roots(fs_info);
 726         kfree(fs_info->extent_root);
 727         kfree(fs_info->tree_root);
 728         kobject_unregister(&fs_info->kobj);
 729         return 0;
 730 }
 731
 732 void btrfs_block_release(struct btrfs_root *root, struct buffer_head *buf)
 733 {
 734         brelse(buf);
 735 }
 736