FS_HAS_SUBTYPE
if (dot && fs && !(fs->fs_flags & FS_HAS_SUBTYPE)) {
.fs_flags = FS_HAS_SUBTYPE | FS_USERNS_MOUNT | FS_ALLOW_IDMAP,
.fs_flags = FS_REQUIRES_DEV | FS_HAS_SUBTYPE | FS_ALLOW_IDMAP,
if (type->fs_flags & FS_HAS_SUBTYPE) {