ud_itrunc
error = ud_itrunc(ip, lp->l_start, 0, cr);
if ((err = ud_itrunc(dp, slot.offset, 0, cr)) != 0) {
(void) ud_itrunc(ip, 0, 0, cr);
(void) ud_itrunc(ip, old_i_size, 0, cr);
if (error = ud_itrunc(ip, vap->va_size, 0, cr)) {
(void) ud_itrunc(ip, 0, 0, cr);
int32_t ud_itrunc(struct ud_inode *, u_offset_t, int32_t, struct cred *);