posix_same_owner
if (posix_same_owner(flc, blocker)) {
if (posix_same_owner(caller, blocker))
if (posix_same_owner(&request->c, &fl->c))
if (!posix_same_owner(&request->c, &fl->c))
if (posix_same_owner(caller_flc, sys_flc))
if (!posix_same_owner(caller, sys))