buffer invalidate routine and checks for B_INVAL flag

[unix-history] / usr / src / sys / kern / kern_physio.c

diff --git a/usr/src/sys/kern/kern_physio.c b/usr/src/sys/kern/kern_physio.c
index 8b4ea5b..ef91a45 100644 (file)
--- a/usr/src/sys/kern/kern_physio.c
+++ b/usr/src/sys/kern/kern_physio.c
@@ -1,4 +1,4 @@
-/*     kern_physio.c   3.1     %H%     */
+/*     kern_physio.c   4.5     %G%     */

 
 #include "../h/param.h"
 #include "../h/systm.h"
 
 #include "../h/param.h"
 #include "../h/systm.h"


@@ -10,6 +10,44 @@
 #include "../h/seg.h"
 #include "../h/pte.h"
 #include "../h/vm.h"
 #include "../h/seg.h"
 #include "../h/pte.h"
 #include "../h/vm.h"

+#include "../h/trace.h"
+
+/*
+ * The following several routines allocate and free
+ * buffers with various side effects.  In general the
+ * arguments to an allocate routine are a device and
+ * a block number, and the value is a pointer to
+ * to the buffer header; the buffer is marked "busy"
+ * so that no one else can touch it.  If the block was
+ * already in core, no I/O need be done; if it is
+ * already busy, the process waits until it becomes free.
+ * The following routines allocate a buffer:
+ *     getblk
+ *     bread
+ *     breada
+ *     baddr   (if it is incore)
+ * Eventually the buffer must be released, possibly with the
+ * side effect of writing it out, by using one of
+ *     bwrite
+ *     bdwrite
+ *     bawrite
+ *     brelse
+ */
+
+#define        BUFHSZ  63
+#define        BUFHASH(blkno)  (blkno % BUFHSZ)
+short  bufhash[BUFHSZ];
+
+/*
+ * Initialize hash links for buffers.
+ */
+bhinit()
+{
+       register int i;
+
+       for (i = 0; i < BUFHSZ; i++)
+               bufhash[i] = -1;
+}

 
 /* #define     DISKMON 1 */
 
 
 /* #define     DISKMON 1 */
 


@@ -38,27 +76,6 @@ struct       buf swbuf[NSWBUF];
 short  swsize[NSWBUF];         /* CAN WE JUST USE B_BCOUNT? */
 int    swpf[NSWBUF];
 
 short  swsize[NSWBUF];         /* CAN WE JUST USE B_BCOUNT? */
 int    swpf[NSWBUF];
 

-/*
- * The following several routines allocate and free
- * buffers with various side effects.  In general the
- * arguments to an allocate routine are a device and
- * a block number, and the value is a pointer to
- * to the buffer header; the buffer is marked "busy"
- * so that no one else can touch it.  If the block was
- * already in core, no I/O need be done; if it is
- * already busy, the process waits until it becomes free.
- * The following routines allocate a buffer:
- *     getblk
- *     bread
- *     breada
- *     baddr   (if it is incore)
- * Eventually the buffer must be released, possibly with the
- * side effect of writing it out, by using one of
- *     bwrite
- *     bdwrite
- *     bawrite
- *     brelse
- */

 
 #ifdef FASTVAX
 #define        notavail(bp) \
 
 #ifdef FASTVAX
 #define        notavail(bp) \


@@ -83,6 +100,9 @@ daddr_t blkno;
 
        bp = getblk(dev, blkno);
        if (bp->b_flags&B_DONE) {
 
        bp = getblk(dev, blkno);
        if (bp->b_flags&B_DONE) {

+#ifdef EPAWNJ
+               trace(TR_BREAD|TR_HIT, dev, blkno);
+#endif

 #ifdef DISKMON
                io_info.ncache++;
 #endif
 #ifdef DISKMON
                io_info.ncache++;
 #endif


@@ -91,6 +111,9 @@ daddr_t blkno;
        bp->b_flags |= B_READ;
        bp->b_bcount = BSIZE;
        (*bdevsw[major(dev)].d_strategy)(bp);
        bp->b_flags |= B_READ;
        bp->b_bcount = BSIZE;
        (*bdevsw[major(dev)].d_strategy)(bp);

+#ifdef EPAWNJ
+       trace(TR_BREAD|TR_MISS, dev, blkno);
+#endif

 #ifdef DISKMON
        io_info.nread++;
 #endif
 #ifdef DISKMON
        io_info.nread++;
 #endif


@@ -117,20 +140,33 @@ daddr_t blkno, rablkno;
                        bp->b_flags |= B_READ;
                        bp->b_bcount = BSIZE;
                        (*bdevsw[major(dev)].d_strategy)(bp);
                        bp->b_flags |= B_READ;
                        bp->b_bcount = BSIZE;
                        (*bdevsw[major(dev)].d_strategy)(bp);

+#ifdef EPAWNJ
+                       trace(TR_BREAD|TR_MISS, dev, blkno);
+#endif

 #ifdef DISKMON
                        io_info.nread++;
 #endif
                        u.u_vm.vm_inblk++;              /* pay for read */
                }
 #ifdef DISKMON
                        io_info.nread++;
 #endif
                        u.u_vm.vm_inblk++;              /* pay for read */
                }

+#ifdef EPAWNJ
+               else
+                       trace(TR_BREAD|TR_HIT, dev, blkno);
+#endif

        }
        if (rablkno && !incore(dev, rablkno)) {
                rabp = getblk(dev, rablkno);
        }
        if (rablkno && !incore(dev, rablkno)) {
                rabp = getblk(dev, rablkno);

-               if (rabp->b_flags & B_DONE)
+               if (rabp->b_flags & B_DONE) {

                        brelse(rabp);
                        brelse(rabp);

-               else {
+#ifdef EPAWNJ
+                       trace(TR_BREAD|TR_HIT|TR_RA, dev, blkno);
+#endif
+               } else {

                        rabp->b_flags |= B_READ|B_ASYNC;
                        rabp->b_bcount = BSIZE;
                        (*bdevsw[major(dev)].d_strategy)(rabp);
                        rabp->b_flags |= B_READ|B_ASYNC;
                        rabp->b_bcount = BSIZE;
                        (*bdevsw[major(dev)].d_strategy)(rabp);

+#ifdef EPAWNJ
+                       trace(TR_BREAD|TR_MISS|TR_RA, dev, rablock);
+#endif

 #ifdef DISKMON
                        io_info.nreada++;
 #endif
 #ifdef DISKMON
                        io_info.nreada++;
 #endif


@@ -160,6 +196,9 @@ register struct buf *bp;
 #endif
        if ((flag&B_DELWRI) == 0)
                u.u_vm.vm_oublk++;              /* noone paid yet */
 #endif
        if ((flag&B_DELWRI) == 0)
                u.u_vm.vm_oublk++;              /* noone paid yet */

+#ifdef EPAWNJ
+       trace(TR_BWRITE, bp->b_dev, dbtofsb(bp->b_blkno));
+#endif

        (*bdevsw[major(bp->b_dev)].d_strategy)(bp);
        if ((flag&B_ASYNC) == 0) {
                iowait(bp);
        (*bdevsw[major(bp->b_dev)].d_strategy)(bp);
        if ((flag&B_ASYNC) == 0) {
                iowait(bp);


@@ -220,8 +259,10 @@ register struct buf *bp;
                bfreelist.b_flags &= ~B_WANTED;
                wakeup((caddr_t)&bfreelist);
        }
                bfreelist.b_flags &= ~B_WANTED;
                wakeup((caddr_t)&bfreelist);
        }

-       if (bp->b_flags&B_ERROR)
+       if ((bp->b_flags&B_ERROR) && bp->b_dev != NODEV) {
+               bunhash(bp);

                bp->b_dev = NODEV;  /* no assoc. on error */
                bp->b_dev = NODEV;  /* no assoc. on error */

+       }

        s = spl6();
        if(bp->b_flags & (B_AGE|B_ERROR)) {
                backp = &bfreelist.av_forw;
        s = spl6();
        if(bp->b_flags & (B_AGE|B_ERROR)) {
                backp = &bfreelist.av_forw;


@@ -249,14 +290,14 @@ dev_t dev;
 daddr_t blkno;
 {
        register struct buf *bp;
 daddr_t blkno;
 {
        register struct buf *bp;

-       register struct buf *dp;

        register int dblkno = fsbtodb(blkno);
 
        register int dblkno = fsbtodb(blkno);
 

-       dp = bdevsw[major(dev)].d_tab;
-       for (bp=dp->b_forw; bp != dp; bp = bp->b_forw)
-               if (bp->b_blkno==dblkno && bp->b_dev==dev)
-                       return(1);
-       return(0);
+       for (bp = &buf[bufhash[BUFHASH(blkno)]]; bp != &buf[-1];
+           bp = &buf[bp->b_hlink])
+               if (bp->b_blkno == dblkno && bp->b_dev == dev
+                                       && !(bp->b_flags & B_INVAL))
+                       return (1);
+       return (0);

 }
 
 struct buf *
 }
 
 struct buf *


@@ -280,31 +321,26 @@ getblk(dev, blkno)
 dev_t dev;
 daddr_t blkno;
 {
 dev_t dev;
 daddr_t blkno;
 {

-       register struct buf *bp;
-       register struct buf *dp;
-#ifdef DISKMON
-       register i;
-#endif
-       register int dblkno = fsbtodb(blkno);
-
-       if(major(dev) >= nblkdev)
-               panic("blkdev");
+       register struct buf *bp, *dp, *ep;
+       register int i, x, dblkno;

 
 

+       if ((unsigned)blkno >= 1 << (sizeof(int)*NBBY-PGSHIFT))
+               blkno = 1 << ((sizeof(int)*NBBY-PGSHIFT) + 1);
+       dblkno = fsbtodb(blkno);

     loop:
     loop:

-       VOID spl0();
-       dp = bdevsw[major(dev)].d_tab;
-       if(dp == NULL)
-               panic("devtab");
-       for (bp=dp->b_forw; bp != dp; bp = bp->b_forw) {
-               if (bp->b_blkno!=dblkno || bp->b_dev!=dev)
+       (void) spl0();
+       for (bp = &buf[bufhash[BUFHASH(blkno)]]; bp != &buf[-1];
+           bp = &buf[bp->b_hlink]) {
+               if (bp->b_blkno != dblkno || bp->b_dev != dev
+                                       || bp->b_flags & B_INVAL)

                        continue;
                        continue;

-               VOID spl6();
+               (void) spl6();

                if (bp->b_flags&B_BUSY) {
                        bp->b_flags |= B_WANTED;
                        sleep((caddr_t)bp, PRIBIO+1);
                        goto loop;
                }
                if (bp->b_flags&B_BUSY) {
                        bp->b_flags |= B_WANTED;
                        sleep((caddr_t)bp, PRIBIO+1);
                        goto loop;
                }

-               VOID spl0();
+               (void) spl0();

 #ifdef DISKMON
                i = 0;
                dp = bp->av_forw;
 #ifdef DISKMON
                i = 0;
                dp = bp->av_forw;


@@ -319,13 +355,18 @@ daddr_t blkno;
                bp->b_flags |= B_CACHE;
                return(bp);
        }
                bp->b_flags |= B_CACHE;
                return(bp);
        }

-       VOID spl6();
+       if (major(dev) >= nblkdev)
+               panic("blkdev");
+       dp = bdevsw[major(dev)].d_tab;
+       if (dp == NULL)
+               panic("devtab");
+       (void) spl6();

        if (bfreelist.av_forw == &bfreelist) {
                bfreelist.b_flags |= B_WANTED;
                sleep((caddr_t)&bfreelist, PRIBIO+1);
                goto loop;
        }
        if (bfreelist.av_forw == &bfreelist) {
                bfreelist.b_flags |= B_WANTED;
                sleep((caddr_t)&bfreelist, PRIBIO+1);
                goto loop;
        }

-       spl0();
+       (void) spl0();

        bp = bfreelist.av_forw;
        notavail(bp);
        if (bp->b_flags & B_DELWRI) {
        bp = bfreelist.av_forw;
        notavail(bp);
        if (bp->b_flags & B_DELWRI) {


@@ -333,6 +374,29 @@ daddr_t blkno;
                bwrite(bp);
                goto loop;
        }
                bwrite(bp);
                goto loop;
        }

+       if (bp->b_dev == NODEV)
+               goto done;
+       /* INLINE EXPANSION OF bunhash(bp) */
+#ifdef EPAWNJ
+       trace(TR_BRELSE, bp->b_dev, dbtofsb(bp->b_blkno));
+#endif
+       (void) spl6();
+       i = BUFHASH(dbtofsb(bp->b_blkno));
+       x = bp - buf;
+       if (bufhash[i] == x) {
+               bufhash[i] = bp->b_hlink;
+       } else {
+               for (ep = &buf[bufhash[i]]; ep != &buf[-1];
+                   ep = &buf[ep->b_hlink])
+                       if (ep->b_hlink == x) {
+                               ep->b_hlink = bp->b_hlink;
+                               goto done;
+                       }
+               panic("getblk");
+       }
+done:
+       (void) spl0();
+       /* END INLINE EXPANSION */

        bp->b_flags = B_BUSY;
        bp->b_back->b_forw = bp->b_forw;
        bp->b_forw->b_back = bp->b_back;
        bp->b_flags = B_BUSY;
        bp->b_back->b_forw = bp->b_forw;
        bp->b_forw->b_back = bp->b_back;


@@ -342,6 +406,9 @@ daddr_t blkno;
        dp->b_forw = bp;
        bp->b_dev = dev;
        bp->b_blkno = dblkno;
        dp->b_forw = bp;
        bp->b_dev = dev;
        bp->b_blkno = dblkno;

+       i = BUFHASH(blkno);
+       bp->b_hlink = bufhash[i];
+       bufhash[i] = bp - buf;

        return(bp);
 }
 
        return(bp);
 }
 


@@ -352,16 +419,15 @@ daddr_t blkno;
 struct buf *
 geteblk()
 {
 struct buf *
 geteblk()
 {

-       register struct buf *bp;
-       register struct buf *dp;
+       register struct buf *bp, *dp;

 
 loop:
 
 loop:

-       VOID spl6();
+       (void) spl6();

        while (bfreelist.av_forw == &bfreelist) {
                bfreelist.b_flags |= B_WANTED;
                sleep((caddr_t)&bfreelist, PRIBIO+1);
        }
        while (bfreelist.av_forw == &bfreelist) {
                bfreelist.b_flags |= B_WANTED;
                sleep((caddr_t)&bfreelist, PRIBIO+1);
        }

-       VOID spl0();
+       (void) spl0();

        dp = &bfreelist;
        bp = bfreelist.av_forw;
        notavail(bp);
        dp = &bfreelist;
        bp = bfreelist.av_forw;
        notavail(bp);


@@ -370,6 +436,12 @@ loop:
                bwrite(bp);
                goto loop;
        }
                bwrite(bp);
                goto loop;
        }

+       if (bp->b_dev != NODEV) {
+#ifdef EPAWNJ
+               trace(TR_BRELSE, bp->b_dev, dbtofsb(bp->b_blkno));
+#endif
+               bunhash(bp);
+       }

        bp->b_flags = B_BUSY;
        bp->b_back->b_forw = bp->b_forw;
        bp->b_forw->b_back = bp->b_back;
        bp->b_flags = B_BUSY;
        bp->b_back->b_forw = bp->b_forw;
        bp->b_forw->b_back = bp->b_back;


@@ -378,9 +450,36 @@ loop:
        dp->b_forw->b_back = bp;
        dp->b_forw = bp;
        bp->b_dev = (dev_t)NODEV;
        dp->b_forw->b_back = bp;
        dp->b_forw = bp;
        bp->b_dev = (dev_t)NODEV;

+       bp->b_hlink = -1;

        return(bp);
 }
 
        return(bp);
 }
 

+bunhash(bp)
+       register struct buf *bp;
+{
+       register struct buf *ep;
+       register int i, x, s;
+
+       if (bp->b_dev == NODEV)
+               return;
+       s = spl6();
+       i = BUFHASH(dbtofsb(bp->b_blkno));
+       x = bp - buf;
+       if (bufhash[i] == x) {
+               bufhash[i] = bp->b_hlink;
+               goto ret;
+       }
+       for (ep = &buf[bufhash[i]]; ep != &buf[-1];
+           ep = &buf[ep->b_hlink])
+               if (ep->b_hlink == x) {
+                       ep->b_hlink = bp->b_hlink;
+                       goto ret;
+               }
+       panic("bunhash");
+ret:
+       splx(s);
+}
+

 /*
  * Wait for I/O completion on the buffer; return errors
  * to the user.
 /*
  * Wait for I/O completion on the buffer; return errors
  * to the user.


@@ -389,10 +488,10 @@ iowait(bp)
 register struct buf *bp;
 {
 
 register struct buf *bp;
 {
 

-       VOID spl6();
+       (void) spl6();

        while ((bp->b_flags&B_DONE)==0)
                sleep((caddr_t)bp, PRIBIO);
        while ((bp->b_flags&B_DONE)==0)
                sleep((caddr_t)bp, PRIBIO);

-       VOID spl0();
+       (void) spl0();

        geterror(bp);
 }
 
        geterror(bp);
 }
 


@@ -427,6 +526,8 @@ register struct buf *bp;
 {
        register int s;
 
 {
        register int s;
 

+       if (bp->b_flags & B_DONE)
+               panic("dup iodone");

        bp->b_flags |= B_DONE;
        if (bp->b_flags & B_DIRTY) {
                if (bp->b_flags & B_ERROR)
        bp->b_flags |= B_DONE;
        if (bp->b_flags & B_DIRTY) {
                if (bp->b_flags & B_ERROR)


@@ -440,6 +541,7 @@ register struct buf *bp;
                if (bswlist.b_flags & B_WANTED)
                        wakeup((caddr_t)&proc[2]);
                splx(s);
                if (bswlist.b_flags & B_WANTED)
                        wakeup((caddr_t)&proc[2]);
                splx(s);

+               return;

        }
        if (bp->b_flags&B_ASYNC)
                brelse(bp);
        }
        if (bp->b_flags&B_ASYNC)
                brelse(bp);


@@ -491,14 +593,14 @@ swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent)
        int p2dp;
        register struct pte *dpte, *vpte;
 
        int p2dp;
        register struct pte *dpte, *vpte;
 

-       VOID spl6();
+       (void) spl6();

        while (bswlist.av_forw == NULL) {
                bswlist.b_flags |= B_WANTED;
                sleep((caddr_t)&bswlist, PSWP+1);
        }
        bp = bswlist.av_forw;
        bswlist.av_forw = bp->av_forw;
        while (bswlist.av_forw == NULL) {
                bswlist.b_flags |= B_WANTED;
                sleep((caddr_t)&bswlist, PSWP+1);
        }
        bp = bswlist.av_forw;
        bswlist.av_forw = bp->av_forw;

-       VOID spl0();
+       (void) spl0();

 
        bp->b_flags = B_BUSY | B_PHYS | rdflg | flag;
        if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0)
 
        bp->b_flags = B_BUSY | B_PHYS | rdflg | flag;
        if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0)


@@ -524,20 +626,20 @@ swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent)
                bp->b_bcount = c;
                bp->b_blkno = dblkno;
                bp->b_dev = dev;
                bp->b_bcount = c;
                bp->b_blkno = dblkno;
                bp->b_dev = dev;

-               if (dev == swapdev)
-                       bp->b_blkno += swplo;
+               if (flag & B_DIRTY) {
+                       swpf[bp - swbuf] = pfcent;
+                       swsize[bp - swbuf] = nbytes;
+               }

                (*bdevsw[major(dev)].d_strategy)(bp);
                if (flag & B_DIRTY) {
                        if (c < nbytes)
                                panic("big push");
                (*bdevsw[major(dev)].d_strategy)(bp);
                if (flag & B_DIRTY) {
                        if (c < nbytes)
                                panic("big push");

-                       swsize[bp - swbuf] = nbytes;
-                       swpf[bp - swbuf] = pfcent;

                        return;
                }
                        return;
                }

-               VOID spl6();
+               (void) spl6();

                while((bp->b_flags&B_DONE)==0)
                        sleep((caddr_t)bp, PSWP);
                while((bp->b_flags&B_DONE)==0)
                        sleep((caddr_t)bp, PSWP);

-               VOID spl0();
+               (void) spl0();

                bp->b_un.b_addr += c;
                bp->b_flags &= ~B_DONE;
                if (bp->b_flags & B_ERROR) {
                bp->b_un.b_addr += c;
                bp->b_flags &= ~B_DONE;
                if (bp->b_flags & B_ERROR) {


@@ -548,7 +650,7 @@ swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent)
                nbytes -= c;
                dblkno += btoc(c);
        }
                nbytes -= c;
                dblkno += btoc(c);
        }

-       VOID spl6();
+       (void) spl6();

        bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY);
        bp->av_forw = bswlist.av_forw;
        bswlist.av_forw = bp;
        bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS|B_PAGET|B_UAREA|B_DIRTY);
        bp->av_forw = bswlist.av_forw;
        bswlist.av_forw = bp;


@@ -557,7 +659,7 @@ swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent)
                wakeup((caddr_t)&bswlist);
                wakeup((caddr_t)&proc[2]);
        }
                wakeup((caddr_t)&bswlist);
                wakeup((caddr_t)&proc[2]);
        }

-       VOID spl0();
+       (void) spl0();

 }
 
 /*
 }
 
 /*


@@ -581,7 +683,7 @@ swkill(p, rout)
         * done by user) after killing it so noone will try
         * to swap it out.
         */
         * done by user) after killing it so noone will try
         * to swap it out.
         */

-       psignal(p, SIGKIL);
+       psignal(p, SIGKILL);

        p->p_flag |= SULOCK;
 }
 
        p->p_flag |= SULOCK;
 }
 


@@ -597,7 +699,7 @@ dev_t dev;
        register struct buf *bp;
 
 loop:
        register struct buf *bp;
 
 loop:

-       VOID spl6();
+       (void) spl6();

        for (bp = bfreelist.av_forw; bp != &bfreelist; bp = bp->av_forw) {
                if (bp->b_flags&B_DELWRI && (dev == NODEV||dev==bp->b_dev)) {
                        bp->b_flags |= B_ASYNC;
        for (bp = bfreelist.av_forw; bp != &bfreelist; bp = bp->av_forw) {
                if (bp->b_flags&B_DELWRI && (dev == NODEV||dev==bp->b_dev)) {
                        bp->b_flags |= B_ASYNC;


@@ -606,7 +708,7 @@ loop:
                        goto loop;
                }
        }
                        goto loop;
                }
        }

-       VOID spl0();
+       (void) spl0();

 }
 
 /*
 }
 
 /*


@@ -635,7 +737,7 @@ unsigned (*mincnt)();
                u.u_error = EFAULT;
                return;
        }
                u.u_error = EFAULT;
                return;
        }

-       VOID spl6();
+       (void) spl6();

        while (bp->b_flags&B_BUSY) {
                bp->b_flags |= B_WANTED;
                sleep((caddr_t)bp, PRIBIO+1);
        while (bp->b_flags&B_BUSY) {
                bp->b_flags |= B_WANTED;
                sleep((caddr_t)bp, PRIBIO+1);


@@ -653,14 +755,14 @@ unsigned (*mincnt)();
                u.u_procp->p_flag |= SPHYSIO;
                vslock(a = bp->b_un.b_addr, c);
                (*strat)(bp);
                u.u_procp->p_flag |= SPHYSIO;
                vslock(a = bp->b_un.b_addr, c);
                (*strat)(bp);

-               VOID spl6();
+               (void) spl6();

                while ((bp->b_flags&B_DONE) == 0)
                        sleep((caddr_t)bp, PRIBIO);
                vsunlock(a, c, rw);
                u.u_procp->p_flag &= ~SPHYSIO;
                if (bp->b_flags&B_WANTED)
                        wakeup((caddr_t)bp);
                while ((bp->b_flags&B_DONE) == 0)
                        sleep((caddr_t)bp, PRIBIO);
                vsunlock(a, c, rw);
                u.u_procp->p_flag &= ~SPHYSIO;
                if (bp->b_flags&B_WANTED)
                        wakeup((caddr_t)bp);

-               VOID spl0();
+               (void) spl0();

                bp->b_un.b_addr += c;
                u.u_count -= c;
                u.u_offset += c;
                bp->b_un.b_addr += c;
                u.u_count -= c;
                u.u_offset += c;


@@ -694,3 +796,26 @@ register struct buf *bp;
                if ((u.u_error = bp->b_error)==0)
                        u.u_error = EIO;
 }
                if ((u.u_error = bp->b_error)==0)
                        u.u_error = EIO;
 }

+
+/*
+ * Invalidate in core blocks belonging to closed or umounted filesystem
+ *
+ * This is not nicely done at all - the buffer ought to be removed from the
+ * hash chains & have its dev/blkno fields clobbered, but unfortunately we
+ * can't do that here, as it is quite possible that the block is still
+ * being used for i/o. Eventually, all disc drivers should be forced to
+ * have a close routine, which ought ensure that the queue is empty, then
+ * properly flush the queues. Until that happy day, this suffices for
+ * correctness.                                                ... kre
+ */
+binval(dev)
+dev_t dev;
+{
+       register struct buf *bp, *dp;
+
+       dp = bdevsw[major(dev)].d_tab;
+
+       for (bp = dp->b_forw; bp != dp; bp = bp->b_forw)
+               if (bp->b_dev == dev)
+                       bp->b_flags |= B_INVAL;
+}