NWRITEERR
if (np->n_flag & NWRITEERR) {
np->n_flag &= ~NWRITEERR;
np->n_flag |= NWRITEERR;
if (np->n_flag & NWRITEERR) {
np->n_flag &= ~NWRITEERR;
if (np->n_flag & NWRITEERR) {
np->n_flag &= ~NWRITEERR;
if (flag & NWRITEERR)