On 2/12/20 2:43 AM, Qu Wenruo wrote:
This function is only used in read_fs_root(), which is just a wrapper of btrfs_get_fs_root(). For all the mentioned essential roots except log root tree, btrfs_get_fs_root() has its own quick path to grab them from fs_info directly, thus no need for key.offset modification. For subvolume trees, btrfs_get_fs_root() with key.offset == -1 is completely fine. For log trees and log root tree, it's impossible to hit them, as for relocation all backrefs are fetched from commit root, which never records log tree blocks. Log tree blocks either get freed in regular transaction commit, or replayed at mount time. At runtime we should never hit an backref for log tree in extent tree. Signed-off-by: Qu Wenruo <wqu@xxxxxxxx>
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx> Thanks, Josef
