VOP_SEEK
return VOP_SEEK(tvp, ap->a_oldoff, ap->a_newoff, ap->a_cred);
error = VOP_SEEK(vp, oldoff, newoff, cred);
error = VOP_SEEK(vp, oldoff, newoff, cred);
int VOP_SEEK(struct vnode *, off_t, off_t, kauth_cred_t);