vdev_dirty_leaves
extern void vdev_dirty_leaves(vdev_t *vd, int flags, uint64_t txg);
vdev_dirty_leaves(vd->vdev_child[c], flags, txg);
vdev_dirty_leaves(vd, VDD_DTL, *txg);
vdev_dirty_leaves(vd, VDD_DTL, *txg);