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#include <linux/module.h>
#include "ctree.h"
#include "disk-io.h"
#include "transaction.h"
#define MAX_CSUM_ITEMS(r) ((((BTRFS_LEAF_DATA_SIZE(r) - \
sizeof(struct btrfs_item) * 2) / \
BTRFS_CRC32_SIZE) - 1))
int btrfs_insert_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 pos,
u64 offset, u64 num_blocks)
{
int ret = 0;
struct btrfs_file_extent_item *item;
struct btrfs_key file_key;
struct btrfs_path *path;
path = btrfs_alloc_path();
BUG_ON(!path);
btrfs_init_path(path);
file_key.objectid = objectid;
file_key.offset = pos;
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
ret = btrfs_insert_empty_item(trans, root, path, &file_key,
sizeof(*item));
BUG_ON(ret);
item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
struct btrfs_file_extent_item);
btrfs_set_file_extent_disk_blocknr(item, offset);
btrfs_set_file_extent_disk_num_blocks(item, num_blocks);
btrfs_set_file_extent_offset(item, 0);
btrfs_set_file_extent_num_blocks(item, num_blocks);
btrfs_set_file_extent_generation(item, trans->transid);
btrfs_set_file_extent_type(item, BTRFS_FILE_EXTENT_REG);
btrfs_mark_buffer_dirty(path->nodes[0]);
btrfs_release_path(root, path);
btrfs_free_path(path);
return 0;
}
struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
u64 objectid, u64 offset,
int cow)
{
int ret;
struct btrfs_key file_key;
struct btrfs_key found_key;
struct btrfs_csum_item *item;
struct btrfs_leaf *leaf;
u64 csum_offset = 0;
int csums_in_item;
file_key.objectid = objectid;
file_key.offset = offset;
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow);
if (ret < 0)
goto fail;
leaf = btrfs_buffer_leaf(path->nodes[0]);
if (ret > 0) {
ret = 1;
if (path->slots[0] == 0)
goto fail;
path->slots[0]--;
btrfs_disk_key_to_cpu(&found_key,
&leaf->items[path->slots[0]].key);
if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
found_key.objectid != objectid) {
goto fail;
}
csum_offset = (offset - found_key.offset) >>
root->fs_info->sb->s_blocksize_bits;
csums_in_item = btrfs_item_size(leaf->items + path->slots[0]);
csums_in_item /= BTRFS_CRC32_SIZE;
if (csum_offset >= csums_in_item) {
ret = -EFBIG;
goto fail;
}
}
item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item);
item = (struct btrfs_csum_item *)((unsigned char *)item +
csum_offset * BTRFS_CRC32_SIZE);
return item;
fail:
if (ret > 0)
ret = -ENOENT;
return ERR_PTR(ret);
}
int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 objectid,
u64 offset, int mod)
{
int ret;
struct btrfs_key file_key;
int ins_len = mod < 0 ? -1 : 0;
int cow = mod != 0;
file_key.objectid = objectid;
file_key.offset = offset;
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY);
ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow);
return ret;
}
int btrfs_csum_file_block(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
u64 objectid, u64 offset,
char *data, size_t len)
{
int ret;
struct btrfs_key file_key;
struct btrfs_key found_key;
struct btrfs_path *path;
struct btrfs_csum_item *item;
struct btrfs_leaf *leaf;
u64 csum_offset;
path = btrfs_alloc_path();
BUG_ON(!path);
file_key.objectid = objectid;
file_key.offset = offset;
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
item = btrfs_lookup_csum(trans, root, path, objectid, offset, 1);
if (!IS_ERR(item))
goto found;
ret = PTR_ERR(item);
if (ret == -EFBIG) {
u32 item_size;
/* we found one, but it isn't big enough yet */
leaf = btrfs_buffer_leaf(path->nodes[0]);
item_size = btrfs_item_size(leaf->items + path->slots[0]);
if ((item_size / BTRFS_CRC32_SIZE) >= MAX_CSUM_ITEMS(root)) {
/* already at max size, make a new one */
goto insert;
}
} else {
/* we didn't find a csum item, insert one */
goto insert;
}
/*
* at this point, we know the tree has an item, but it isn't big
* enough yet to put our csum in. Grow it
*/
btrfs_release_path(root, path);
ret = btrfs_search_slot(trans, root, &file_key, path,
BTRFS_CRC32_SIZE, 1);
if (ret < 0)
goto fail;
if (ret == 0) {
BUG();
}
if (path->slots[0] == 0) {
goto insert;
}
path->slots[0]--;
leaf = btrfs_buffer_leaf(path->nodes[0]);
btrfs_disk_key_to_cpu(&found_key, &leaf->items[path->slots[0]].key);
csum_offset = (offset - found_key.offset) >>
root->fs_info->sb->s_blocksize_bits;
if (btrfs_key_type(&found_key) != BTRFS_CSUM_ITEM_KEY ||
found_key.objectid != objectid ||
csum_offset >= MAX_CSUM_ITEMS(root)) {
WARN_ON(1);
goto insert;
}
if (csum_offset >= btrfs_item_size(leaf->items + path->slots[0]) /
BTRFS_CRC32_SIZE) {
u32 diff = (csum_offset + 1) * BTRFS_CRC32_SIZE;
diff = diff - btrfs_item_size(leaf->items + path->slots[0]);
WARN_ON(diff != BTRFS_CRC32_SIZE);
ret = btrfs_extend_item(trans, root, path, diff);
BUG_ON(ret);
goto csum;
}
insert:
btrfs_release_path(root, path);
csum_offset = 0;
ret = btrfs_insert_empty_item(trans, root, path, &file_key,
BTRFS_CRC32_SIZE);
if (ret != 0) {
printk("at insert for %Lu %u %Lu ret is %d\n", file_key.objectid, file_key.flags, file_key.offset, ret);
WARN_ON(1);
goto fail;
}
csum:
item = btrfs_item_ptr(btrfs_buffer_leaf(path->nodes[0]), path->slots[0],
struct btrfs_csum_item);
ret = 0;
item = (struct btrfs_csum_item *)((unsigned char *)item +
csum_offset * BTRFS_CRC32_SIZE);
found:
btrfs_check_bounds(&item->csum, BTRFS_CRC32_SIZE,
path->nodes[0]->b_data,
root->fs_info->sb->s_blocksize);
ret = btrfs_csum_data(root, data, len, &item->csum);
btrfs_mark_buffer_dirty(path->nodes[0]);
fail:
btrfs_release_path(root, path);
btrfs_free_path(path);
return ret;
}
int btrfs_csum_verify_file_block(struct btrfs_root *root,
u64 objectid, u64 offset,
char *data, size_t len)
{
int ret;
struct btrfs_key file_key;
struct btrfs_path *path;
struct btrfs_csum_item *item;
char result[BTRFS_CRC32_SIZE];
path = btrfs_alloc_path();
BUG_ON(!path);
btrfs_init_path(path);
file_key.objectid = objectid;
file_key.offset = offset;
file_key.flags = 0;
btrfs_set_key_type(&file_key, BTRFS_CSUM_ITEM_KEY);
mutex_lock(&root->fs_info->fs_mutex);
item = btrfs_lookup_csum(NULL, root, path, objectid, offset, 0);
if (IS_ERR(item)) {
ret = PTR_ERR(item);
/* a csum that isn't present is a preallocated region. */
if (ret == -ENOENT || ret == -EFBIG)
ret = 1;
goto fail;
}
ret = btrfs_csum_data(root, data, len, result);
WARN_ON(ret);
if (memcmp(result, &item->csum, BTRFS_CRC32_SIZE))
ret = 1;
fail:
btrfs_release_path(root, path);
btrfs_free_path(path);
mutex_unlock(&root->fs_info->fs_mutex);
return ret;
}
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