XREP_AGF_BNOBT
if (!xrep_check_btree_root(sc, &fab[XREP_AGF_BNOBT]) ||
agf->agf_bno_root = cpu_to_be32(fab[XREP_AGF_BNOBT].root);
agf->agf_bno_level = cpu_to_be32(fab[XREP_AGF_BNOBT].height);
[XREP_AGF_BNOBT] = {