| #include <linux/module.h> |
| #include "ctree.h" |
| #include "disk-io.h" |
| #include "transaction.h" |
| #include "print-tree.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 disk_num_blocks, |
| 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, disk_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)) { |
| 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]); |
| if (diff != BTRFS_CRC32_SIZE) |
| goto insert; |
| 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) { |
| 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_truncate(struct btrfs_trans_handle *trans, |
| struct btrfs_root *root, struct btrfs_path *path, |
| u64 isize) |
| { |
| struct btrfs_key key; |
| struct btrfs_leaf *leaf = btrfs_buffer_leaf(path->nodes[0]); |
| int slot = path->slots[0]; |
| int ret; |
| u32 new_item_size; |
| u64 new_item_span; |
| u64 blocks; |
| |
| btrfs_disk_key_to_cpu(&key, &leaf->items[slot].key); |
| if (isize <= key.offset) |
| return 0; |
| new_item_span = isize - key.offset; |
| blocks = (new_item_span + root->blocksize - 1) >> |
| root->fs_info->sb->s_blocksize_bits; |
| new_item_size = blocks * BTRFS_CRC32_SIZE; |
| if (new_item_size >= btrfs_item_size(leaf->items + slot)) |
| return 0; |
| ret = btrfs_truncate_item(trans, root, path, new_item_size); |
| BUG_ON(ret); |
| 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 = -ENOENT; |
| 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; |
| } |
| |