diff options
Diffstat (limited to 'fs/btrfs/tree-mod-log.c')
| -rw-r--r-- | fs/btrfs/tree-mod-log.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/fs/btrfs/tree-mod-log.c b/fs/btrfs/tree-mod-log.c index b10170e691d1..1e52584f3fa5 100644 --- a/fs/btrfs/tree-mod-log.c +++ b/fs/btrfs/tree-mod-log.c @@ -884,3 +884,26 @@ int btrfs_old_root_level(struct btrfs_root *root, u64 time_seq) return level; } +/* + * Return the lowest sequence number in the tree modification log. + * + * Return the sequence number of the oldest tree modification log user, which + * corresponds to the lowest sequence number of all existing users. If there are + * no users it returns 0. + */ +u64 btrfs_tree_mod_log_lowest_seq(struct btrfs_fs_info *fs_info) +{ + u64 ret = 0; + + read_lock(&fs_info->tree_mod_log_lock); + if (!list_empty(&fs_info->tree_mod_seq_list)) { + struct btrfs_seq_list *elem; + + elem = list_first_entry(&fs_info->tree_mod_seq_list, + struct btrfs_seq_list, list); + ret = elem->seq; + } + read_unlock(&fs_info->tree_mod_log_lock); + + return ret; +} |