file-item.c revision d6025579531b7ea170ba283b171ff7a6bf7d0e12 
1#include <linux/module.h>
2#include "ctree.h"
3#include "disk-io.h"
4#include "transaction.h"
5
6int btrfs_alloc_file_extent(struct btrfs_trans_handle *trans,
7			       struct btrfs_root *root,
8			       u64 objectid, u64 offset,
9			       u64 num_blocks, u64 hint_block,
10			       u64 *result)
11{
12	struct btrfs_key ins;
13	int ret = 0;
14	struct btrfs_file_extent_item *item;
15	struct btrfs_key file_key;
16	struct btrfs_path path;
17
18	btrfs_init_path(&path);
19	ret = btrfs_alloc_extent(trans, root, num_blocks, hint_block,
20				 (u64)-1, objectid, &ins);
21	BUG_ON(ret);
22	file_key.objectid = objectid;
23	file_key.offset = offset;
24	file_key.flags = 0;
25	btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
26
27	ret = btrfs_insert_empty_item(trans, root, &path, &file_key,
28				      sizeof(*item));
29	BUG_ON(ret);
30	item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
31			      struct btrfs_file_extent_item);
32	btrfs_set_file_extent_disk_blocknr(item, ins.objectid);
33	btrfs_set_file_extent_disk_num_blocks(item, ins.offset);
34	btrfs_set_file_extent_offset(item, 0);
35	btrfs_set_file_extent_num_blocks(item, ins.offset);
36	btrfs_set_file_extent_generation(item, trans->transid);
37	btrfs_mark_buffer_dirty(path.nodes[0]);
38	*result = ins.objectid;
39	btrfs_release_path(root, &path);
40	return 0;
41}
42
43int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
44			     struct btrfs_root *root,
45			     struct btrfs_path *path, u64 objectid,
46			     u64 offset, int mod)
47{
48	int ret;
49	struct btrfs_key file_key;
50	int ins_len = mod < 0 ? -1 : 0;
51	int cow = mod != 0;
52
53	file_key.objectid = objectid;
54	file_key.offset = offset;
55	file_key.flags = 0;
56	btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
57	ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
58	return ret;
59}
60
61int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
62			  struct btrfs_root *root,
63			  u64 objectid, u64 offset,
64			  char *data, size_t len)
65{
66	int ret;
67	struct btrfs_key file_key;
68	struct btrfs_path path;
69	struct btrfs_csum_item *item;
70
71	btrfs_init_path(&path);
72	file_key.objectid = objectid;
73	file_key.offset = offset;
74	file_key.flags = 0;
75	btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
76	ret = btrfs_insert_empty_item(trans, root, &path, &file_key,
77				      BTRFS_CSUM_SIZE);
78	if (ret != 0 && ret != -EEXIST)
79		goto fail;
80	item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
81			      struct btrfs_csum_item);
82	ret = 0;
83	ret = btrfs_csum_data(root, data, len, item->csum);
84	btrfs_mark_buffer_dirty(path.nodes[0]);
85fail:
86	btrfs_release_path(root, &path);
87	return ret;
88}
89
90int btrfs_csum_verify_file_block(struct btrfs_root *root,
91				 u64 objectid, u64 offset,
92				 char *data, size_t len)
93{
94	int ret;
95	struct btrfs_key file_key;
96	struct btrfs_path path;
97	struct btrfs_csum_item *item;
98	char result[BTRFS_CSUM_SIZE];
99
100	btrfs_init_path(&path);
101	file_key.objectid = objectid;
102	file_key.offset = offset;
103	file_key.flags = 0;
104	btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
105	ret = btrfs_search_slot(NULL, root, &file_key, &path, 0, 0);
106	if (ret)
107		goto fail;
108	item = btrfs_item_ptr(btrfs_buffer_leaf(path.nodes[0]), path.slots[0],
109			      struct btrfs_csum_item);
110	ret = 0;
111	ret = btrfs_csum_data(root, data, len, result);
112	WARN_ON(ret);
113	if (memcmp(result, item->csum, BTRFS_CSUM_SIZE))
114		ret = 1;
115fail:
116	btrfs_release_path(root, &path);
117	return ret;
118}
119
120