add_aeb
ret = add_aeb(ai, free, pnum, ec, scrub);
ret = add_aeb(ai, &ai->free, be32_to_cpu(fmec->pnum),
ret = add_aeb(ai, &used, be32_to_cpu(fmec->pnum),
ret = add_aeb(ai, &used, be32_to_cpu(fmec->pnum),
ret = add_aeb(ai, &ai->erase, be32_to_cpu(fmec->pnum),