arc_untransform
err = arc_untransform(dnode_abuf, os->os_spa, &zb, B_TRUE);
err = arc_untransform(db->db_buf, spa, &zb, B_FALSE);
err = arc_untransform(db->db_buf, db->db_objset->os_spa,
err = arc_untransform((*osp)->os_phys_buf, (*osp)->os_spa,
err = arc_untransform(os->os_phys_buf, os->os_spa,
int arc_untransform(arc_buf_t *buf, spa_t *spa, const zbookmark_phys_t *zb,