Qu Wenruo | 1d5a7b7 | 2020-06-24 18:03:01 +0200 | [diff] [blame^] | 1 | // SPDX-License-Identifier: GPL-2.0+ |
| 2 | |
| 3 | #include "ctree.h" |
| 4 | |
| 5 | int btrfs_find_last_root(struct btrfs_root *root, u64 objectid, |
| 6 | struct btrfs_root_item *item, struct btrfs_key *key) |
| 7 | { |
| 8 | struct btrfs_path *path; |
| 9 | struct btrfs_key search_key; |
| 10 | struct btrfs_key found_key; |
| 11 | struct extent_buffer *l; |
| 12 | int ret; |
| 13 | int slot; |
| 14 | |
| 15 | path = btrfs_alloc_path(); |
| 16 | if (!path) |
| 17 | return -ENOMEM; |
| 18 | |
| 19 | search_key.objectid = objectid; |
| 20 | search_key.type = BTRFS_ROOT_ITEM_KEY; |
| 21 | search_key.offset = (u64)-1; |
| 22 | |
| 23 | ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0); |
| 24 | if (ret < 0) |
| 25 | goto out; |
| 26 | if (path->slots[0] == 0) { |
| 27 | ret = -ENOENT; |
| 28 | goto out; |
| 29 | } |
| 30 | |
| 31 | BUG_ON(ret == 0); |
| 32 | l = path->nodes[0]; |
| 33 | slot = path->slots[0] - 1; |
| 34 | btrfs_item_key_to_cpu(l, &found_key, slot); |
| 35 | if (found_key.type != BTRFS_ROOT_ITEM_KEY || |
| 36 | found_key.objectid != objectid) { |
| 37 | ret = -ENOENT; |
| 38 | goto out; |
| 39 | } |
| 40 | read_extent_buffer(l, item, btrfs_item_ptr_offset(l, slot), |
| 41 | sizeof(*item)); |
| 42 | memcpy(key, &found_key, sizeof(found_key)); |
| 43 | ret = 0; |
| 44 | out: |
| 45 | btrfs_free_path(path); |
| 46 | return ret; |
| 47 | } |