diff options
Diffstat (limited to 'fs/btrfs/disk-io.c')
| -rw-r--r-- | fs/btrfs/disk-io.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index aa92c0de0cd68..3b456c3331a29 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -4735,3 +4735,58 @@ static int btrfs_cleanup_transaction(struct btrfs_fs_info *fs_info) return 0; } + +int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid) +{ + struct btrfs_path *path; + int ret; + struct extent_buffer *l; + struct btrfs_key search_key; + struct btrfs_key found_key; + int slot; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + search_key.objectid = BTRFS_LAST_FREE_OBJECTID; + search_key.type = -1; + search_key.offset = (u64)-1; + ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0); + if (ret < 0) + goto error; + BUG_ON(ret == 0); /* Corruption */ + if (path->slots[0] > 0) { + slot = path->slots[0] - 1; + l = path->nodes[0]; + btrfs_item_key_to_cpu(l, &found_key, slot); + *objectid = max_t(u64, found_key.objectid, + BTRFS_FIRST_FREE_OBJECTID - 1); + } else { + *objectid = BTRFS_FIRST_FREE_OBJECTID - 1; + } + ret = 0; +error: + btrfs_free_path(path); + return ret; +} + +int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid) +{ + int ret; + mutex_lock(&root->objectid_mutex); + + if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) { + btrfs_warn(root->fs_info, + "the objectid of root %llu reaches its highest value", + root->root_key.objectid); + ret = -ENOSPC; + goto out; + } + + *objectid = ++root->highest_objectid; + ret = 0; +out: + mutex_unlock(&root->objectid_mutex); + return ret; +} |