| 1 | #include <linux/module.h> |
| 2 | #include "ctree.h" |
| 3 | #include "disk-io.h" |
| 4 | #include "transaction.h" |
| 5 | |
| 6 | #define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \ |
| 7 | sizeof(struct btrfs_item)) / \ |
| 8 | sizeof(struct btrfs_csum_item)) - 1)) |
| 9 | int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans, |
| 10 | struct btrfs_root *root, |
| 11 | u64 objectid, u64 offset, |
| 12 | u64 num_blocks, u64 hint_block, |
| 13 | u64 *result) |
| 14 | { |
| 15 | struct btrfs_key ins; |
| 16 | int ret = 0; |
| 17 | struct btrfs_file_extent_item *item; |
| 18 | struct btrfs_key file_key; |
| 19 | struct btrfs_path *path; |
| 20 | |
| 21 | path = btrfs_alloc_path(); |
| 22 | BUG_ON(!path); |
| 23 | btrfs_init_path(path); |
| 24 | ret = btrfs_alloc_extent(trans, root, num_blocks, hint_block, |
| 25 | (u64)-1, &ins); |
| 26 | BUG_ON(ret); |
| 27 | file_key.objectid = objectid; |
| 28 | file_key.offset = offset; |
| 29 | file_key.flags = 0; |
| 30 | btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY); |
| 31 | |
| 32 | ret = btrfs_insert_empty_item(trans, root, path, &file_key, |
| 33 | sizeof(*item)); |
| 34 | BUG_ON(ret); |
| 35 | item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0], |
| 36 | struct btrfs_file_extent_item); |
| 37 | btrfs_set_file_extent_disk_blocknr(item, ins.objectid); |
| 38 | btrfs_set_file_extent_disk_num_blocks(item, ins.offset); |
| 39 | btrfs_set_file_extent_offset(item, 0); |
| 40 | btrfs_set_file_extent_num_blocks(item, ins.offset); |
| 41 | btrfs_set_file_extent_generation(item, trans->transid); |
| 42 | btrfs_mark_buffer_dirty(path->nodes[0]); |
| 43 | *result = ins.objectid; |
| 44 | btrfs_release_path(root, path); |
| 45 | btrfs_free_path(path); |
| 46 | return 0; |
| 47 | } |
| 48 | |
| 49 | static struct btrfs_csum_item *__lookup_csum_item(struct btrfs_root *root, |
| 50 | struct btrfs_path *path, |
| 51 | u64 objectid, u64 offset) |
| 52 | { |
| 53 | int ret; |
| 54 | struct btrfs_key file_key; |
| 55 | struct btrfs_key found_key; |
| 56 | struct btrfs_csum_item *item; |
| 57 | struct btrfs_leaf *leaf; |
| 58 | u64 csum_offset = 0; |
| 59 | |
| 60 | file_key.objectid = objectid; |
| 61 | file_key.offset = offset; |
| 62 | file_key.flags = 0; |
| 63 | btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY); |
| 64 | ret = btrfs_search_slot(NULL, root, &file_key, path, 0, 0); |
| 65 | if (ret < 0) |
| 66 | goto fail; |
| 67 | leaf = btrfs_buffer_leaf(path->nodes[0]); |
| 68 | if (ret > 0) { |
| 69 | ret = 1; |
| 70 | if (path->slots[0] == 0) |
| 71 | goto fail; |
| 72 | path->slots[0]--; |
| 73 | btrfs_disk_key_to_cpu(&found_key, |
| 74 | &leaf->items[path->slots[0]].key); |
| 75 | if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY || |
| 76 | found_key.objectid != objectid) { |
| 77 | goto fail; |
| 78 | } |
| 79 | csum_offset = (offset - found_key.offset) >> |
| 80 | root->fs_info->sb->s_blocksize_bits; |
| 81 | if (csum_offset >= |
| 82 | btrfs_item_size(leaf->items + path->slots[0]) / |
| 83 | sizeof(struct btrfs_csum_item)) { |
| 84 | goto fail; |
| 85 | } |
| 86 | } |
| 87 | item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); |
| 88 | item += csum_offset; |
| 89 | return item; |
| 90 | fail: |
| 91 | if (ret > 0) |
| 92 | ret = -EIO; |
| 93 | return ERR_PTR(ret); |
| 94 | } |
| 95 | |
| 96 | |
| 97 | int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, |
| 98 | struct btrfs_root *root, |
| 99 | struct btrfs_path *path, u64 objectid, |
| 100 | u64 offset, int mod) |
| 101 | { |
| 102 | int ret; |
| 103 | struct btrfs_key file_key; |
| 104 | int ins_len = mod < 0 ? -1 : 0; |
| 105 | int cow = mod != 0; |
| 106 | struct btrfs_csum_item *csum_item; |
| 107 | |
| 108 | csum_item = __lookup_csum_item(root, path, objectid, offset); |
| 109 | if (IS_ERR(csum_item)) |
| 110 | return PTR_ERR(csum_item); |
| 111 | file_key.objectid = objectid; |
| 112 | file_key.offset = btrfs_csum_extent_offset(csum_item); |
| 113 | file_key.flags = 0; |
| 114 | btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY); |
| 115 | btrfs_release_path(root, path); |
| 116 | ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow); |
| 117 | return ret; |
| 118 | } |
| 119 | |
| 120 | int btrfs_csum_file_block(struct btrfs_trans_handle *trans, |
| 121 | struct btrfs_root *root, |
| 122 | u64 objectid, u64 offset, |
| 123 | u64 extent_offset, |
| 124 | char *data, size_t len) |
| 125 | { |
| 126 | int ret; |
| 127 | struct btrfs_key file_key; |
| 128 | struct btrfs_key found_key; |
| 129 | struct btrfs_path *path; |
| 130 | struct btrfs_csum_item *item; |
| 131 | struct btrfs_leaf *leaf; |
| 132 | u64 csum_offset; |
| 133 | |
| 134 | path = btrfs_alloc_path(); |
| 135 | BUG_ON(!path); |
| 136 | btrfs_init_path(path); |
| 137 | file_key.objectid = objectid; |
| 138 | file_key.offset = offset; |
| 139 | file_key.flags = 0; |
| 140 | btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY); |
| 141 | ret = btrfs_search_slot(trans, root, &file_key, path, |
| 142 | sizeof(struct btrfs_csum_item), 1); |
| 143 | if (ret < 0) |
| 144 | goto fail; |
| 145 | if (ret == 0) { |
| 146 | csum_offset = 0; |
| 147 | goto csum; |
| 148 | } |
| 149 | if (path->slots[0] == 0) { |
| 150 | btrfs_release_path(root, path); |
| 151 | goto insert; |
| 152 | } |
| 153 | path->slots[0]--; |
| 154 | leaf = btrfs_buffer_leaf(path->nodes[0]); |
| 155 | btrfs_disk_key_to_cpu(&found_key, &leaf->items[path->slots[0]].key); |
| 156 | csum_offset = (offset - found_key.offset) >> |
| 157 | root->fs_info->sb->s_blocksize_bits; |
| 158 | if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY || |
| 159 | found_key.objectid != objectid || |
| 160 | csum_offset >= MAX_CSUM_ITEMS(root)) { |
| 161 | btrfs_release_path(root, path); |
| 162 | goto insert; |
| 163 | } |
| 164 | if (csum_offset >= btrfs_item_size(leaf->items + path->slots[0]) / |
| 165 | sizeof(struct btrfs_csum_item)) { |
| 166 | ret = btrfs_extend_item(trans, root, path, |
| 167 | sizeof(struct btrfs_csum_item)); |
| 168 | BUG_ON(ret); |
| 169 | goto csum; |
| 170 | } |
| 171 | |
| 172 | insert: |
| 173 | csum_offset = 0; |
| 174 | ret = btrfs_insert_empty_item(trans, root, path, &file_key, |
| 175 | sizeof(struct btrfs_csum_item)); |
| 176 | if (ret != 0 && ret != -EEXIST) |
| 177 | goto fail; |
| 178 | csum: |
| 179 | item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0], |
| 180 | struct btrfs_csum_item); |
| 181 | ret = 0; |
| 182 | item += csum_offset; |
| 183 | ret = btrfs_csum_data(root, data, len, item->csum); |
| 184 | btrfs_set_csum_extent_offset(item, extent_offset); |
| 185 | btrfs_mark_buffer_dirty(path->nodes[0]); |
| 186 | fail: |
| 187 | btrfs_release_path(root, path); |
| 188 | btrfs_free_path(path); |
| 189 | return ret; |
| 190 | } |
| 191 | |
| 192 | int btrfs_csum_verify_file_block(struct btrfs_root *root, |
| 193 | u64 objectid, u64 offset, |
| 194 | char *data, size_t len) |
| 195 | { |
| 196 | int ret; |
| 197 | struct btrfs_key file_key; |
| 198 | struct btrfs_path *path; |
| 199 | struct btrfs_csum_item *item; |
| 200 | char result[BTRFS_CSUM_SIZE]; |
| 201 | |
| 202 | path = btrfs_alloc_path(); |
| 203 | BUG_ON(!path); |
| 204 | btrfs_init_path(path); |
| 205 | file_key.objectid = objectid; |
| 206 | file_key.offset = offset; |
| 207 | file_key.flags = 0; |
| 208 | btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY); |
| 209 | mutex_lock(&root->fs_info->fs_mutex); |
| 210 | |
| 211 | item = __lookup_csum_item(root, path, objectid, offset); |
| 212 | if (IS_ERR(item)) { |
| 213 | ret = PTR_ERR(item); |
| 214 | goto fail; |
| 215 | } |
| 216 | |
| 217 | ret = btrfs_csum_data(root, data, len, result); |
| 218 | WARN_ON(ret); |
| 219 | if (memcmp(result, item->csum, BTRFS_CSUM_SIZE)) |
| 220 | ret = 1; |
| 221 | fail: |
| 222 | btrfs_release_path(root, path); |
| 223 | btrfs_free_path(path); |
| 224 | mutex_unlock(&root->fs_info->fs_mutex); |
| 225 | return ret; |
| 226 | } |
| 227 | |