bpobj_enqueue_subobj
bpobj_enqueue_subobj(&dle->dle_bpobj, obj, tx);
bpobj_enqueue_subobj(bpo, dle->dle_bpobj.bpo_object, tx);
void bpobj_enqueue_subobj(bpobj_t *bpo, uint64_t subobj, dmu_tx_t *tx);