spec_node_lookup_by_dev
if (spec_node_lookup_by_dev(VBLK, dev, VDEAD_NOWAIT, &vp) == 0) {
if (spec_node_lookup_by_dev(vp->v_type, vp->v_rdev, VDEAD_NOWAIT, &vq)
return (spec_node_lookup_by_dev(type, dev, VDEAD_NOWAIT, vpp) == 0);
while (spec_node_lookup_by_dev(type, dev, 0, &vp) == 0) {
while (spec_node_lookup_by_dev(type, dev, VDEAD_NOWAIT, &vq)
int spec_node_lookup_by_dev(enum vtype, dev_t, int, vnode_t **);