cg_old_btotoff
int32_t cg_old_btotoff; /* (int32) block totals per cylinder */
n->cg_old_btotoff = bswap32(o->cg_old_btotoff);
btotoff = n->cg_old_btotoff;
btotoff = bswap32(n->cg_old_btotoff);
acg.cg_old_btotoff = start;
acg.cg_old_boff = acg.cg_old_btotoff +