B_VALIDSUSPWRT
ibp->b_flags |= B_VALIDSUSPWRT;
nbp->b_flags |= B_VALIDSUSPWRT;
ibp->b_flags |= B_VALIDSUSPWRT;
bp->b_flags |= B_VALIDSUSPWRT | B_NOCOPY;
bp->b_flags |= B_VALIDSUSPWRT;
bp->b_flags |= B_VALIDSUSPWRT;
if ((bp->b_flags & B_VALIDSUSPWRT) == 0 &&
bp->b_flags &= ~(B_VALIDSUSPWRT | B_NOCOPY);