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