VOP_LOOKUP
error = VOP_LOOKUP(vp, &parent, &cn);
error = VOP_LOOKUP(lvp, uvpp, &cn);
if ((error = VOP_LOOKUP(dp, &ndp->ni_vp, cnp)) != 0) {
if ((error = VOP_LOOKUP(dp, vpp, cnp)) != 0) {
int VOP_LOOKUP(struct vnode *, struct vnode **, struct componentname *);