BD_DOMAIN
bp->b_domain = BD_DOMAIN(bd);
KASSERT(bp->b_domain == BD_DOMAIN(bd),
bp->b_domain, (int)BD_DOMAIN(bd)));
BIT_CLR(BUF_DOMAINS, BD_DOMAIN(bd), &bdlodirty);
BIT_CLR(BUF_DOMAINS, BD_DOMAIN(bd), &bdhidirty);
BIT_SET(BUF_DOMAINS, BD_DOMAIN(bd), &bdlodirty);
BIT_SET(BUF_DOMAINS, BD_DOMAIN(bd), &bdhidirty);