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) * 2) / \
8 BTRFS_CRC32_SIZE) - 1))
9 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
10 struct btrfs_root *root,
11 u64 objectid, u64 pos,
12 u64 offset, u64 disk_num_blocks,
16 struct btrfs_file_extent_item *item;
17 struct btrfs_key file_key;
18 struct btrfs_path *path;
20 path = btrfs_alloc_path();
22 btrfs_init_path(path);
23 file_key.objectid = objectid;
24 file_key.offset = pos;
26 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
28 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
31 item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
32 struct btrfs_file_extent_item);
33 btrfs_set_file_extent_disk_blocknr(item, offset);
34 btrfs_set_file_extent_disk_num_blocks(item, disk_num_blocks);
35 btrfs_set_file_extent_offset(item, 0);
36 btrfs_set_file_extent_num_blocks(item, num_blocks);
37 btrfs_set_file_extent_generation(item, trans->transid);
38 btrfs_set_file_extent_type(item, BTRFS_FILE_EXTENT_REG);
39 btrfs_mark_buffer_dirty(path->nodes[0]);
41 btrfs_release_path(root, path);
42 btrfs_free_path(path);
46 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
47 struct btrfs_root *root,
48 struct btrfs_path *path,
49 u64 objectid, u64 offset,
53 struct btrfs_key file_key;
54 struct btrfs_key found_key;
55 struct btrfs_csum_item *item;
56 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(trans, root, &file_key, path, 0, cow);
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;
81 csums_in_item = btrfs_item_size(leaf->items + path->slots[0]);
82 csums_in_item /= BTRFS_CRC32_SIZE;
84 if (csum_offset >= csums_in_item) {
89 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
90 item = (struct btrfs_csum_item *)((unsigned char *)item +
91 csum_offset * BTRFS_CRC32_SIZE);
100 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
101 struct btrfs_root *root,
102 struct btrfs_path *path, u64 objectid,
106 struct btrfs_key file_key;
107 int ins_len = mod < 0 ? -1 : 0;
110 file_key.objectid = objectid;
111 file_key.offset = offset;
113 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
114 ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
118 int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
119 struct btrfs_root *root,
120 u64 objectid, u64 offset,
121 char *data, size_t len)
124 struct btrfs_key file_key;
125 struct btrfs_key found_key;
126 struct btrfs_path *path;
127 struct btrfs_csum_item *item;
128 struct btrfs_leaf *leaf;
131 path = btrfs_alloc_path();
134 file_key.objectid = objectid;
135 file_key.offset = offset;
137 btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
139 item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
145 /* we found one, but it isn't big enough yet */
146 leaf = btrfs_buffer_leaf(path->nodes[0]);
147 item_size = btrfs_item_size(leaf->items + path->slots[0]);
148 if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
149 /* already at max size, make a new one */
153 /* we didn't find a csum item, insert one */
158 * at this point, we know the tree has an item, but it isn't big
159 * enough yet to put our csum in. Grow it
161 btrfs_release_path(root, path);
162 ret = btrfs_search_slot(trans, root, &file_key, path,
163 BTRFS_CRC32_SIZE, 1);
169 if (path->slots[0] == 0) {
173 leaf = btrfs_buffer_leaf(path->nodes[0]);
174 btrfs_disk_key_to_cpu(&found_key, &leaf->items[path->slots[0]].key);
175 csum_offset = (offset - found_key.offset) >>
176 root->fs_info->sb->s_blocksize_bits;
177 if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
178 found_key.objectid != objectid ||
179 csum_offset >= MAX_CSUM_ITEMS(root)) {
182 if (csum_offset >= btrfs_item_size(leaf->items + path->slots[0]) /
184 u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
185 diff = diff - btrfs_item_size(leaf->items + path->slots[0]);
186 if (diff != BTRFS_CRC32_SIZE)
188 ret = btrfs_extend_item(trans, root, path, diff);
194 btrfs_release_path(root, path);
196 ret = btrfs_insert_empty_item(trans, root, path, &file_key,
199 printk("at insert for %Lu %u %Lu ret is %d\n", file_key.objectid, file_key.flags, file_key.offset, ret);
204 item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
205 struct btrfs_csum_item);
207 item = (struct btrfs_csum_item *)((unsigned char *)item +
208 csum_offset * BTRFS_CRC32_SIZE);
210 btrfs_check_bounds(&item->csum, BTRFS_CRC32_SIZE,
211 path->nodes[0]->b_data,
212 root->fs_info->sb->s_blocksize);
213 ret = btrfs_csum_data(root, data, len, &item->csum);
214 btrfs_mark_buffer_dirty(path->nodes[0]);
216 btrfs_release_path(root, path);
217 btrfs_free_path(path);
221 int btrfs_csum_verify_file_block(struct btrfs_root *root,
222 u64 objectid, u64 offset,
223 char *data, size_t len)
226 struct btrfs_key file_key;
227 struct btrfs_path *path;
228 struct btrfs_csum_item *item;
229 char result[BTRFS_CRC32_SIZE];
231 path = btrfs_alloc_path();
233 btrfs_init_path(path);
234 file_key.objectid = objectid;
235 file_key.offset = offset;
237 btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
238 mutex_lock(&root->fs_info->fs_mutex);
240 item = btrfs_lookup_csum(NULL, root, path, objectid, offset, 0);
243 /* a csum that isn't present is a preallocated region. */
244 if (ret == -ENOENT || ret == -EFBIG)
249 ret = btrfs_csum_data(root, data, len, result);
251 if (memcmp(result, &item->csum, BTRFS_CRC32_SIZE))
254 btrfs_release_path(root, path);
255 btrfs_free_path(path);
256 mutex_unlock(&root->fs_info->fs_mutex);