Chris Mason | 6cbd557 | 2007-06-12 09:07:21 -0400 | [diff] [blame^] | 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 | |
Chris Mason | 2e635a2 | 2007-03-21 11:12:56 -0400 | [diff] [blame] | 19 | #include <linux/module.h> |
Chris Mason | 1e1d270 | 2007-03-15 19:03:33 -0400 | [diff] [blame] | 20 | #include "ctree.h" |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 21 | #include "disk-io.h" |
Chris Mason | 9f5fae2 | 2007-03-20 14:38:32 -0400 | [diff] [blame] | 22 | #include "transaction.h" |
Chris Mason | 1de037a | 2007-05-29 15:17:08 -0400 | [diff] [blame] | 23 | #include "print-tree.h" |
Chris Mason | 1e1d270 | 2007-03-15 19:03:33 -0400 | [diff] [blame] | 24 | |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 25 | #define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \ |
Chris Mason | 509659c | 2007-05-10 12:36:17 -0400 | [diff] [blame] | 26 | sizeof(struct btrfs_item) * 2) / \ |
| 27 | BTRFS_CRC32_SIZE) - 1)) |
Chris Mason | b18c668 | 2007-04-17 13:26:50 -0400 | [diff] [blame] | 28 | int btrfs_insert_file_extent(struct btrfs_trans_handle *trans, |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 29 | struct btrfs_root *root, |
Chris Mason | b18c668 | 2007-04-17 13:26:50 -0400 | [diff] [blame] | 30 | u64 objectid, u64 pos, |
Chris Mason | 3a68637 | 2007-05-24 13:35:57 -0400 | [diff] [blame] | 31 | u64 offset, u64 disk_num_blocks, |
| 32 | u64 num_blocks) |
Chris Mason | 9f5fae2 | 2007-03-20 14:38:32 -0400 | [diff] [blame] | 33 | { |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 34 | int ret = 0; |
| 35 | struct btrfs_file_extent_item *item; |
| 36 | struct btrfs_key file_key; |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 37 | struct btrfs_path *path; |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 38 | |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 39 | path = btrfs_alloc_path(); |
| 40 | BUG_ON(!path); |
| 41 | btrfs_init_path(path); |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 42 | file_key.objectid = objectid; |
Chris Mason | b18c668 | 2007-04-17 13:26:50 -0400 | [diff] [blame] | 43 | file_key.offset = pos; |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 44 | file_key.flags = 0; |
| 45 | btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY); |
| 46 | |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 47 | ret = btrfs_insert_empty_item(trans, root, path, &file_key, |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 48 | sizeof(*item)); |
Chris Mason | 9773a78 | 2007-03-27 11:26:26 -0400 | [diff] [blame] | 49 | BUG_ON(ret); |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 50 | item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0], |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 51 | struct btrfs_file_extent_item); |
Chris Mason | b18c668 | 2007-04-17 13:26:50 -0400 | [diff] [blame] | 52 | btrfs_set_file_extent_disk_blocknr(item, offset); |
Chris Mason | 3a68637 | 2007-05-24 13:35:57 -0400 | [diff] [blame] | 53 | btrfs_set_file_extent_disk_num_blocks(item, disk_num_blocks); |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 54 | btrfs_set_file_extent_offset(item, 0); |
Chris Mason | b18c668 | 2007-04-17 13:26:50 -0400 | [diff] [blame] | 55 | btrfs_set_file_extent_num_blocks(item, num_blocks); |
Chris Mason | 71951f3 | 2007-03-27 09:16:29 -0400 | [diff] [blame] | 56 | btrfs_set_file_extent_generation(item, trans->transid); |
Chris Mason | 236454d | 2007-04-19 13:37:44 -0400 | [diff] [blame] | 57 | btrfs_set_file_extent_type(item, BTRFS_FILE_EXTENT_REG); |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 58 | btrfs_mark_buffer_dirty(path->nodes[0]); |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 59 | |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 60 | btrfs_release_path(root, path); |
| 61 | btrfs_free_path(path); |
Chris Mason | 9f5fae2 | 2007-03-20 14:38:32 -0400 | [diff] [blame] | 62 | return 0; |
| 63 | } |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 64 | |
Chris Mason | b18c668 | 2007-04-17 13:26:50 -0400 | [diff] [blame] | 65 | struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans, |
| 66 | struct btrfs_root *root, |
| 67 | struct btrfs_path *path, |
| 68 | u64 objectid, u64 offset, |
| 69 | int cow) |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 70 | { |
| 71 | int ret; |
| 72 | struct btrfs_key file_key; |
| 73 | struct btrfs_key found_key; |
| 74 | struct btrfs_csum_item *item; |
| 75 | struct btrfs_leaf *leaf; |
| 76 | u64 csum_offset = 0; |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 77 | int csums_in_item; |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 78 | |
| 79 | file_key.objectid = objectid; |
| 80 | file_key.offset = offset; |
| 81 | file_key.flags = 0; |
| 82 | btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY); |
Chris Mason | b18c668 | 2007-04-17 13:26:50 -0400 | [diff] [blame] | 83 | ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow); |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 84 | if (ret < 0) |
| 85 | goto fail; |
| 86 | leaf = btrfs_buffer_leaf(path->nodes[0]); |
| 87 | if (ret > 0) { |
| 88 | ret = 1; |
Chris Mason | 70b2bef | 2007-04-17 15:39:32 -0400 | [diff] [blame] | 89 | if (path->slots[0] == 0) |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 90 | goto fail; |
| 91 | path->slots[0]--; |
| 92 | btrfs_disk_key_to_cpu(&found_key, |
| 93 | &leaf->items[path->slots[0]].key); |
| 94 | if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY || |
| 95 | found_key.objectid != objectid) { |
| 96 | goto fail; |
| 97 | } |
| 98 | csum_offset = (offset - found_key.offset) >> |
| 99 | root->fs_info->sb->s_blocksize_bits; |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 100 | csums_in_item = btrfs_item_size(leaf->items + path->slots[0]); |
Chris Mason | 509659c | 2007-05-10 12:36:17 -0400 | [diff] [blame] | 101 | csums_in_item /= BTRFS_CRC32_SIZE; |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 102 | |
| 103 | if (csum_offset >= csums_in_item) { |
| 104 | ret = -EFBIG; |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 105 | goto fail; |
| 106 | } |
| 107 | } |
| 108 | item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); |
Chris Mason | 509659c | 2007-05-10 12:36:17 -0400 | [diff] [blame] | 109 | item = (struct btrfs_csum_item *)((unsigned char *)item + |
| 110 | csum_offset * BTRFS_CRC32_SIZE); |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 111 | return item; |
| 112 | fail: |
| 113 | if (ret > 0) |
Chris Mason | b18c668 | 2007-04-17 13:26:50 -0400 | [diff] [blame] | 114 | ret = -ENOENT; |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 115 | return ERR_PTR(ret); |
| 116 | } |
| 117 | |
| 118 | |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 119 | int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, |
| 120 | struct btrfs_root *root, |
| 121 | struct btrfs_path *path, u64 objectid, |
Chris Mason | 9773a78 | 2007-03-27 11:26:26 -0400 | [diff] [blame] | 122 | u64 offset, int mod) |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 123 | { |
| 124 | int ret; |
| 125 | struct btrfs_key file_key; |
| 126 | int ins_len = mod < 0 ? -1 : 0; |
| 127 | int cow = mod != 0; |
| 128 | |
| 129 | file_key.objectid = objectid; |
Chris Mason | 70b2bef | 2007-04-17 15:39:32 -0400 | [diff] [blame] | 130 | file_key.offset = offset; |
Chris Mason | dee26a9 | 2007-03-26 16:00:06 -0400 | [diff] [blame] | 131 | file_key.flags = 0; |
| 132 | btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY); |
| 133 | ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow); |
| 134 | return ret; |
| 135 | } |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 136 | |
| 137 | int btrfs_csum_file_block(struct btrfs_trans_handle *trans, |
| 138 | struct btrfs_root *root, |
| 139 | u64 objectid, u64 offset, |
| 140 | char *data, size_t len) |
| 141 | { |
| 142 | int ret; |
| 143 | struct btrfs_key file_key; |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 144 | struct btrfs_key found_key; |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 145 | struct btrfs_path *path; |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 146 | struct btrfs_csum_item *item; |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 147 | struct btrfs_leaf *leaf; |
| 148 | u64 csum_offset; |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 149 | |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 150 | path = btrfs_alloc_path(); |
| 151 | BUG_ON(!path); |
Chris Mason | b18c668 | 2007-04-17 13:26:50 -0400 | [diff] [blame] | 152 | |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 153 | file_key.objectid = objectid; |
| 154 | file_key.offset = offset; |
| 155 | file_key.flags = 0; |
| 156 | btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY); |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 157 | |
| 158 | item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1); |
| 159 | if (!IS_ERR(item)) |
| 160 | goto found; |
| 161 | ret = PTR_ERR(item); |
| 162 | if (ret == -EFBIG) { |
| 163 | u32 item_size; |
| 164 | /* we found one, but it isn't big enough yet */ |
| 165 | leaf = btrfs_buffer_leaf(path->nodes[0]); |
| 166 | item_size = btrfs_item_size(leaf->items + path->slots[0]); |
Chris Mason | 509659c | 2007-05-10 12:36:17 -0400 | [diff] [blame] | 167 | if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) { |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 168 | /* already at max size, make a new one */ |
| 169 | goto insert; |
| 170 | } |
| 171 | } else { |
| 172 | /* we didn't find a csum item, insert one */ |
| 173 | goto insert; |
| 174 | } |
| 175 | |
| 176 | /* |
| 177 | * at this point, we know the tree has an item, but it isn't big |
| 178 | * enough yet to put our csum in. Grow it |
| 179 | */ |
| 180 | btrfs_release_path(root, path); |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 181 | ret = btrfs_search_slot(trans, root, &file_key, path, |
Chris Mason | 509659c | 2007-05-10 12:36:17 -0400 | [diff] [blame] | 182 | BTRFS_CRC32_SIZE, 1); |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 183 | if (ret < 0) |
| 184 | goto fail; |
| 185 | if (ret == 0) { |
Chris Mason | b18c668 | 2007-04-17 13:26:50 -0400 | [diff] [blame] | 186 | BUG(); |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 187 | } |
| 188 | if (path->slots[0] == 0) { |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 189 | goto insert; |
| 190 | } |
| 191 | path->slots[0]--; |
| 192 | leaf = btrfs_buffer_leaf(path->nodes[0]); |
| 193 | btrfs_disk_key_to_cpu(&found_key, &leaf->items[path->slots[0]].key); |
| 194 | csum_offset = (offset - found_key.offset) >> |
| 195 | root->fs_info->sb->s_blocksize_bits; |
| 196 | if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY || |
| 197 | found_key.objectid != objectid || |
| 198 | csum_offset >= MAX_CSUM_ITEMS(root)) { |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 199 | goto insert; |
| 200 | } |
| 201 | if (csum_offset >= btrfs_item_size(leaf->items + path->slots[0]) / |
Chris Mason | 509659c | 2007-05-10 12:36:17 -0400 | [diff] [blame] | 202 | BTRFS_CRC32_SIZE) { |
| 203 | u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE; |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 204 | diff = diff - btrfs_item_size(leaf->items + path->slots[0]); |
Chris Mason | 3a68637 | 2007-05-24 13:35:57 -0400 | [diff] [blame] | 205 | if (diff != BTRFS_CRC32_SIZE) |
| 206 | goto insert; |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 207 | ret = btrfs_extend_item(trans, root, path, diff); |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 208 | BUG_ON(ret); |
| 209 | goto csum; |
| 210 | } |
| 211 | |
| 212 | insert: |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 213 | btrfs_release_path(root, path); |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 214 | csum_offset = 0; |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 215 | ret = btrfs_insert_empty_item(trans, root, path, &file_key, |
Chris Mason | 509659c | 2007-05-10 12:36:17 -0400 | [diff] [blame] | 216 | BTRFS_CRC32_SIZE); |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 217 | if (ret != 0) { |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 218 | WARN_ON(1); |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 219 | goto fail; |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 220 | } |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 221 | csum: |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 222 | item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0], |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 223 | struct btrfs_csum_item); |
| 224 | ret = 0; |
Chris Mason | 509659c | 2007-05-10 12:36:17 -0400 | [diff] [blame] | 225 | item = (struct btrfs_csum_item *)((unsigned char *)item + |
| 226 | csum_offset * BTRFS_CRC32_SIZE); |
Chris Mason | b18c668 | 2007-04-17 13:26:50 -0400 | [diff] [blame] | 227 | found: |
Chris Mason | 509659c | 2007-05-10 12:36:17 -0400 | [diff] [blame] | 228 | btrfs_check_bounds(&item->csum, BTRFS_CRC32_SIZE, |
| 229 | path->nodes[0]->b_data, |
| 230 | root->fs_info->sb->s_blocksize); |
| 231 | ret = btrfs_csum_data(root, data, len, &item->csum); |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 232 | btrfs_mark_buffer_dirty(path->nodes[0]); |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 233 | fail: |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 234 | btrfs_release_path(root, path); |
| 235 | btrfs_free_path(path); |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 236 | return ret; |
| 237 | } |
| 238 | |
Chris Mason | 1de037a | 2007-05-29 15:17:08 -0400 | [diff] [blame] | 239 | int btrfs_csum_truncate(struct btrfs_trans_handle *trans, |
| 240 | struct btrfs_root *root, struct btrfs_path *path, |
| 241 | u64 isize) |
| 242 | { |
| 243 | struct btrfs_key key; |
| 244 | struct btrfs_leaf *leaf = btrfs_buffer_leaf(path->nodes[0]); |
| 245 | int slot = path->slots[0]; |
| 246 | int ret; |
| 247 | u32 new_item_size; |
| 248 | u64 new_item_span; |
| 249 | u64 blocks; |
| 250 | |
| 251 | btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key); |
| 252 | if (isize <= key.offset) |
| 253 | return 0; |
| 254 | new_item_span = isize - key.offset; |
Chris Mason | 84f54cf | 2007-06-12 07:43:08 -0400 | [diff] [blame] | 255 | blocks = (new_item_span + root->blocksize - 1) >> |
| 256 | root->fs_info->sb->s_blocksize_bits; |
Chris Mason | 1de037a | 2007-05-29 15:17:08 -0400 | [diff] [blame] | 257 | new_item_size = blocks * BTRFS_CRC32_SIZE; |
| 258 | if (new_item_size >= btrfs_item_size(leaf->items + slot)) |
| 259 | return 0; |
| 260 | ret = btrfs_truncate_item(trans, root, path, new_item_size); |
| 261 | BUG_ON(ret); |
| 262 | return ret; |
| 263 | } |
| 264 | |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 265 | int btrfs_csum_verify_file_block(struct btrfs_root *root, |
| 266 | u64 objectid, u64 offset, |
| 267 | char *data, size_t len) |
| 268 | { |
| 269 | int ret; |
| 270 | struct btrfs_key file_key; |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 271 | struct btrfs_path *path; |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 272 | struct btrfs_csum_item *item; |
Chris Mason | 509659c | 2007-05-10 12:36:17 -0400 | [diff] [blame] | 273 | char result[BTRFS_CRC32_SIZE]; |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 274 | |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 275 | path = btrfs_alloc_path(); |
| 276 | BUG_ON(!path); |
| 277 | btrfs_init_path(path); |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 278 | file_key.objectid = objectid; |
| 279 | file_key.offset = offset; |
| 280 | file_key.flags = 0; |
| 281 | btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY); |
Chris Mason | 2da566e | 2007-04-02 15:43:21 -0400 | [diff] [blame] | 282 | mutex_lock(&root->fs_info->fs_mutex); |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 283 | |
Chris Mason | b18c668 | 2007-04-17 13:26:50 -0400 | [diff] [blame] | 284 | item = btrfs_lookup_csum(NULL, root, path, objectid, offset, 0); |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 285 | if (IS_ERR(item)) { |
| 286 | ret = PTR_ERR(item); |
Chris Mason | a429e51 | 2007-04-18 16:15:28 -0400 | [diff] [blame] | 287 | /* a csum that isn't present is a preallocated region. */ |
| 288 | if (ret == -ENOENT || ret == -EFBIG) |
Chris Mason | 3a68637 | 2007-05-24 13:35:57 -0400 | [diff] [blame] | 289 | ret = -ENOENT; |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 290 | goto fail; |
Chris Mason | 6567e83 | 2007-04-16 09:22:45 -0400 | [diff] [blame] | 291 | } |
| 292 | |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 293 | ret = btrfs_csum_data(root, data, len, result); |
| 294 | WARN_ON(ret); |
Chris Mason | 509659c | 2007-05-10 12:36:17 -0400 | [diff] [blame] | 295 | if (memcmp(result, &item->csum, BTRFS_CRC32_SIZE)) |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 296 | ret = 1; |
| 297 | fail: |
Chris Mason | 5caf2a0 | 2007-04-02 11:20:42 -0400 | [diff] [blame] | 298 | btrfs_release_path(root, path); |
| 299 | btrfs_free_path(path); |
Chris Mason | 2da566e | 2007-04-02 15:43:21 -0400 | [diff] [blame] | 300 | mutex_unlock(&root->fs_info->fs_mutex); |
Chris Mason | f254e52 | 2007-03-29 15:15:27 -0400 | [diff] [blame] | 301 | return ret; |
| 302 | } |
| 303 | |