vn_writechk
error = vn_writechk(vp);
(error = vn_writechk(vp)) == 0) {
if ((error = vn_writechk(vp)) == 0) {
if ((error = vn_writechk(vp)) == 0) {
if ((error = vn_writechk(vp)) == 0) {
error = vn_writechk(vp);
error = vn_writechk(vp);
int vn_writechk (struct vnode *vp);