vdev_close
vdev_close(vd);
vdev_close(rvd);
extern void vdev_close(vdev_t *);
vdev_close(vd);
vdev_close(vd);
vdev_close(vd);
vdev_close(vd);
vdev_close(vd->vdev_child[c]);
vdev_close(vd->vdev_child[c]);
vdev_close(vd->vdev_child[c]);