bpobj_free
bpobj_free(os, objarray[blkoff], tx);
bpobj_free(bpo->bpo_os, subobj, tx);
bpobj_free(os, dlobj, tx);
bpobj_free(os, obj, tx);
bpobj_free(dp->dp_meta_objset,
void bpobj_free(objset_t *os, uint64_t obj, dmu_tx_t *tx);