BLKDEV_IOSIZE
bsize = BLKDEV_IOSIZE;
bsize = BLKDEV_IOSIZE;
fmp->max_write = BLKDEV_IOSIZE;
if (sbp->f_iosize > BLKDEV_IOSIZE)
sbp->f_iosize = BLKDEV_IOSIZE;
else if (st->blksize > BLKDEV_IOSIZE)
st->blksize = BLKDEV_IOSIZE;
vap->va_blocksize = BLKDEV_IOSIZE;
vap->va_blocksize = BLKDEV_IOSIZE;
vap->va_blocksize = BLKDEV_IOSIZE;