1 #include <linux/module.h>
4 #include "transaction.h"
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,
17 struct btrfs_file_extent_item *item;
18 struct btrfs_key file_key;
19 struct btrfs_path *path;
21 path = btrfs_alloc_path();
23 btrfs_init_path(path);
24 ret = btrfs_alloc_extent(trans, root, num_blocks, hint_block,
27 file_key.objectid = objectid;
28 file_key.offset = offset;
30 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
32 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
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);
49 static struct btrfs_csum_item *__lookup_csum_item(struct btrfs_root *root,
50 struct btrfs_path *path,
51 u64 objectid, u64 offset)
54 struct btrfs_key file_key;
55 struct btrfs_key found_key;
56 struct btrfs_csum_item *item;
57 struct btrfs_leaf *leaf;
60 file_key.objectid = objectid;
61 file_key.offset = offset;
63 btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
64 ret = btrfs_search_slot(NULL, root, &file_key, path, 0, 0);
67 leaf = btrfs_buffer_leaf(path->nodes[0]);
70 if (path->slots[0] == 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) {
79 csum_offset = (offset - found_key.offset) >>
80 root->fs_info->sb->s_blocksize_bits;
82 btrfs_item_size(leaf->items + path->slots[0]) /
83 sizeof(struct btrfs_csum_item)) {
87 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
97 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
98 struct btrfs_root *root,
99 struct btrfs_path *path, u64 objectid,
103 struct btrfs_key file_key;
104 int ins_len = mod < 0 ? -1 : 0;
106 struct btrfs_csum_item *csum_item;
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);
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);
120 int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
121 struct btrfs_root *root,
122 u64 objectid, u64 offset,
124 char *data, size_t len)
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;
134 path = btrfs_alloc_path();
136 btrfs_init_path(path);
137 file_key.objectid = objectid;
138 file_key.offset = offset;
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);
149 if (path->slots[0] == 0) {
150 btrfs_release_path(root, path);
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);
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));
174 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
175 sizeof(struct btrfs_csum_item));
176 if (ret != 0 && ret != -EEXIST)
179 item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
180 struct btrfs_csum_item);
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]);
187 btrfs_release_path(root, path);
188 btrfs_free_path(path);
192 int btrfs_csum_verify_file_block(struct btrfs_root *root,
193 u64 objectid, u64 offset,
194 char *data, size_t len)
197 struct btrfs_key file_key;
198 struct btrfs_path *path;
199 struct btrfs_csum_item *item;
200 char result[BTRFS_CSUM_SIZE];
202 path = btrfs_alloc_path();
204 btrfs_init_path(path);
205 file_key.objectid = objectid;
206 file_key.offset = offset;
208 btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
209 mutex_lock(&root->fs_info->fs_mutex);
211 item = __lookup_csum_item(root, path, objectid, offset);
217 ret = btrfs_csum_data(root, data, len, result);
219 if (memcmp(result, item->csum, BTRFS_CSUM_SIZE))
222 btrfs_release_path(root, path);
223 btrfs_free_path(path);
224 mutex_unlock(&root->fs_info->fs_mutex);