cg_old_boff
int32_t cg_old_boff; /* (u_int16) free block positions */
n->cg_old_boff = bswap32(o->cg_old_boff);
boff = n->cg_old_boff;
boff = bswap32(n->cg_old_boff);
acg.cg_old_boff = acg.cg_old_btotoff +
acg.cg_iusedoff = acg.cg_old_boff +