acl_nfs4_check
int acl_nfs4_check(const struct acl *aclp, int is_directory);
error = acl_nfs4_check(aclp, vp->v_type == VDIR);
KASSERT(acl_nfs4_check(aclp, vp->v_type == VDIR) == 0,
return (acl_nfs4_check(ap->a_aclp, is_directory));