-
- bp = getblk(dev, blkno);
- if (bp->b_flags&B_DONE) {
-#ifdef DISKMON
- io_info.ncache++;
-#endif
- return(bp);
- }
- bp->b_flags |= B_READ;
- bp->b_bcount = BSIZE;
- (*bdevsw[major(dev)].d_strategy)(bp);
-#ifdef DISKMON
- io_info.nread++;
-#endif
- u.u_vm.vm_inblk++; /* pay for read */
- iowait(bp);
- return(bp);
-}
-
-/*
- * Read in the block, like bread, but also start I/O on the
- * read-ahead block (which is not allocated to the caller)
- */
-struct buf *
-breada(dev, blkno, rablkno)
-dev_t dev;
-daddr_t blkno, rablkno;
-{
- register struct buf *bp, *rabp;
-
- bp = NULL;
- if (!incore(dev, blkno)) {
- bp = getblk(dev, blkno);
- if ((bp->b_flags&B_DONE) == 0) {
- bp->b_flags |= B_READ;
- bp->b_bcount = BSIZE;
- (*bdevsw[major(dev)].d_strategy)(bp);
-#ifdef DISKMON
- io_info.nread++;
-#endif
- u.u_vm.vm_inblk++; /* pay for read */
- }
- }
- if (rablkno && !incore(dev, rablkno)) {
- rabp = getblk(dev, rablkno);
- if (rabp->b_flags & B_DONE)
- brelse(rabp);
- else {
- rabp->b_flags |= B_READ|B_ASYNC;
- rabp->b_bcount = BSIZE;
- (*bdevsw[major(dev)].d_strategy)(rabp);
-#ifdef DISKMON
- io_info.nreada++;
-#endif
- u.u_vm.vm_inblk++; /* pay in advance */
- }
- }
- if(bp == NULL)
- return(bread(dev, blkno));
- iowait(bp);
- return(bp);
-}
-
-/*
- * Write the buffer, waiting for completion.
- * Then release the buffer.
- */
-bwrite(bp)
-register struct buf *bp;
-{
- register flag;
-
- flag = bp->b_flags;
- bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI | B_AGE);
- bp->b_bcount = BSIZE;
-#ifdef DISKMON
- io_info.nwrite++;
-#endif
- if ((flag&B_DELWRI) == 0)
- u.u_vm.vm_oublk++; /* noone paid yet */
- (*bdevsw[major(bp->b_dev)].d_strategy)(bp);
- if ((flag&B_ASYNC) == 0) {
- iowait(bp);
- brelse(bp);
- } else if (flag & B_DELWRI)
- bp->b_flags |= B_AGE;
- else
- geterror(bp);
-}
-
-/*
- * Release the buffer, marking it so that if it is grabbed
- * for another purpose it will be written out before being
- * given up (e.g. when writing a partial block where it is
- * assumed that another write for the same block will soon follow).
- * This can't be done for magtape, since writes must be done
- * in the same order as requested.
- */
-bdwrite(bp)
-register struct buf *bp;
-{
- register struct buf *dp;
-
- if ((bp->b_flags&B_DELWRI) == 0)
- u.u_vm.vm_oublk++; /* noone paid yet */
- dp = bdevsw[major(bp->b_dev)].d_tab;
- if(dp->b_flags & B_TAPE)
- bawrite(bp);
- else {
- bp->b_flags |= B_DELWRI | B_DONE;
- brelse(bp);
- }
-}
-
-/*
- * Release the buffer, start I/O on it, but don't wait for completion.
- */
-bawrite(bp)
-register struct buf *bp;
-{
-
- bp->b_flags |= B_ASYNC;
- bwrite(bp);
-}
-
-/*
- * release the buffer, with no I/O implied.
- */
-brelse(bp)
-register struct buf *bp;
-{
- register struct buf **backp;
- register s;
-
- if (bp->b_flags&B_WANTED)
- wakeup((caddr_t)bp);
- if (bfreelist.b_flags&B_WANTED) {
- bfreelist.b_flags &= ~B_WANTED;
- wakeup((caddr_t)&bfreelist);
- }
- if ((bp->b_flags&B_ERROR) && bp->b_dev != NODEV) {
- bunhash(bp);
- bp->b_dev = NODEV; /* no assoc. on error */
- }
- s = spl6();
- if(bp->b_flags & (B_AGE|B_ERROR)) {
- backp = &bfreelist.av_forw;
- (*backp)->av_back = bp;
- bp->av_forw = *backp;
- *backp = bp;
- bp->av_back = &bfreelist;
- } else {
- backp = &bfreelist.av_back;
- (*backp)->av_forw = bp;
- bp->av_back = *backp;
- *backp = bp;
- bp->av_forw = &bfreelist;
- }
- bp->b_flags &= ~(B_WANTED|B_BUSY|B_ASYNC|B_AGE);
- splx(s);
-}
-
-/* HASHING IS A GUN LIKE CHANGE, THIS IS THE SAFETY */
-struct buf *
-oincore(dev, blkno)