bpobj_iterate
VERIFY3U(0, ==, bpobj_iterate(&bpo,
VERIFY0(bpobj_iterate(&ds_next->ds_deadlist.dl_bpobj,
err = bpobj_iterate(&dp->dp_free_bpobj,
err = bpobj_iterate(&dp->dp_obsolete_bpobj,
VERIFY3U(bpobj_iterate(&spa->spa_deferred_bpobj,
int bpobj_iterate(bpobj_t *bpo, bpobj_itor_t func, void *arg, dmu_tx_t *tx);