hammer_uuid_t
static hammer_uuid_t fsid, fstype;
hammer_uuid_t shared_uuid; /* shared uuid (match required) */
hammer_uuid_t unique_uuid; /* unique uuid of this master/slave */
hammer_uuid_t vol_fsid; /* identify filesystem */
hammer_uuid_t vol_fstype; /* identify filesystem type */
hammer_uuid_t uid;
hammer_uuid_t gid;