nfs_crsame
int nfs_crsame(struct ucred *cr1, struct ucred *cr2);
!nfs_crsame(cred, np->n_rucred)) {
!nfs_crsame(cred, np->n_wucred)) {
if ((ap->a_mode & FREAD) && !nfs_crsame(ap->a_cred, np->n_rucred)) {
if ((ap->a_mode & FWRITE) && !nfs_crsame(ap->a_cred, np->n_wucred)) {