have to save v_mountf before vput'ing the vnode

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

diff --git a/usr/src/sys/kern/vfs_bio.c b/usr/src/sys/kern/vfs_bio.c
index 0c785ee..a702845 100644 (file)
--- a/usr/src/sys/kern/vfs_bio.c
+++ b/usr/src/sys/kern/vfs_bio.c
@@ -1,162 +1,148 @@
-/*     vfs_bio.c       3.11    %G%     */
-
-#include "../h/param.h"
-#include "../h/systm.h"
-#include "../h/dir.h"
-#include "../h/user.h"
-#include "../h/buf.h"
-#include "../h/conf.h"
-#include "../h/proc.h"
-#include "../h/seg.h"
-#include "../h/pte.h"
-#include "../h/vm.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.
+ * Copyright (c) 1982, 1986, 1989 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms are permitted
+ * provided that the above copyright notice and this paragraph are
+ * duplicated in all such forms and that any documentation,
+ * advertising materials, and other materials related to such
+ * distribution and use acknowledge that the software was developed
+ * by the University of California, Berkeley.  The name of the
+ * University may not be used to endorse or promote products derived
+ * from this software without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ *     @(#)vfs_bio.c   7.17 (Berkeley) %G%

  */
  */

-bhinit()
-{
-       register int i;
-
-       for (i = 0; i < BUFHSZ; i++)
-               bufhash[i] = -1;
-}

 
 

-/* #define     DISKMON 1 */
-
-#ifdef DISKMON
-struct {
-       int     nbuf;
-       long    nread;
-       long    nreada;
-       long    ncache;
-       long    nwrite;
-       long    bufcount[NBUF];
-} io_info;
-#endif
-
-/*
- * Swap IO headers -
- * They contain the necessary information for the swap I/O.
- * At any given time, a swap header can be in three
- * different lists. When free it is in the free list, 
- * when allocated and the I/O queued, it is on the swap 
- * device list, and finally, if the operation was a dirty 
- * page push, when the I/O completes, it is inserted 
- * in a list of cleaned pages to be processed by the pageout daemon.
- */
-struct buf swbuf[NSWBUF];
-short  swsize[NSWBUF];         /* CAN WE JUST USE B_BCOUNT? */
-int    swpf[NSWBUF];
-
-
-#ifdef FASTVAX
-#define        notavail(bp) \
-{ \
-       int s = spl6(); \
-       (bp)->av_back->av_forw = (bp)->av_forw; \
-       (bp)->av_forw->av_back = (bp)->av_back; \
-       (bp)->b_flags |= B_BUSY; \
-       splx(s); \
-}
-#endif
+#include "param.h"
+#include "user.h"
+#include "buf.h"
+#include "vnode.h"
+#include "mount.h"
+#include "trace.h"
+#include "ucred.h"

 
 /*
  * Read in (if necessary) the block and return a buffer pointer.
  */
 
 /*
  * Read in (if necessary) the block and return a buffer pointer.
  */

-struct buf *
-bread(dev, blkno)
-dev_t dev;
-daddr_t blkno;
+bread(vp, blkno, size, cred, bpp)
+       struct vnode *vp;
+       daddr_t blkno;
+       int size;
+       struct ucred *cred;
+       struct buf **bpp;
+#ifdef SECSIZE
+       long secsize;
+#endif SECSIZE

 {
        register struct buf *bp;
 
 {
        register struct buf *bp;
 

-       bp = getblk(dev, blkno);
-       if (bp->b_flags&B_DONE) {
-#ifdef DISKMON
-               io_info.ncache++;
-#endif
-               return(bp);
+       if (size == 0)
+               panic("bread: size 0");
+#ifdef SECSIZE
+       bp = getblk(dev, blkno, size, secsize);
+#else SECSIZE
+       *bpp = bp = getblk(vp, blkno, size);
+#endif SECSIZE
+       if (bp->b_flags&(B_DONE|B_DELWRI)) {
+               trace(TR_BREADHIT, pack(vp->v_mount->m_fsid[0], size), blkno);
+               return (0);

        }
        bp->b_flags |= B_READ;
        }
        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);
+       if (bp->b_bcount > bp->b_bufsize)
+               panic("bread");
+       if (bp->b_rcred == NOCRED && cred != NOCRED) {
+               crhold(cred);
+               bp->b_rcred = cred;
+       }
+       VOP_STRATEGY(bp);
+       trace(TR_BREADMISS, pack(vp->v_mount->m_fsid[0], size), blkno);
+       u.u_ru.ru_inblock++;            /* pay for read */
+       return (biowait(bp));

 }
 
 /*
  * Read in the block, like bread, but also start I/O on the
  * read-ahead block (which is not allocated to the caller)
  */
 }
 
 /*
  * 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;
+breada(vp, blkno, size, rablkno, rabsize, cred, bpp)
+       struct vnode *vp;
+       daddr_t blkno; int size;
+#ifdef SECSIZE
+       long secsize;
+#endif SECSIZE
+       daddr_t rablkno; int rabsize;
+       struct ucred *cred;
+       struct buf **bpp;

 {
        register struct buf *bp, *rabp;
 
        bp = NULL;
 {
        register struct buf *bp, *rabp;
 
        bp = NULL;

-       if (!incore(dev, blkno)) {
-               bp = getblk(dev, blkno);
-               if ((bp->b_flags&B_DONE) == 0) {
+       /*
+        * If the block isn't in core, then allocate
+        * a buffer and initiate i/o (getblk checks
+        * for a cache hit).
+        */
+       if (!incore(vp, blkno)) {
+               *bpp = bp = getblk(vp, blkno, size);
+#endif SECSIZE
+               if ((bp->b_flags&(B_DONE|B_DELWRI)) == 0) {

                        bp->b_flags |= B_READ;
                        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 (bp->b_bcount > bp->b_bufsize)
+                               panic("breada");
+                       if (bp->b_rcred == NOCRED && cred != NOCRED) {
+                               crhold(cred);
+                               bp->b_rcred = cred;
+                       }
+                       VOP_STRATEGY(bp);
+                       trace(TR_BREADMISS, pack(vp->v_mount->m_fsid[0], size),
+                           blkno);
+                       u.u_ru.ru_inblock++;            /* pay for read */
+               } else
+                       trace(TR_BREADHIT, pack(vp->v_mount->m_fsid[0], size),
+                           blkno);

        }
        }

-       if (rablkno && !incore(dev, rablkno)) {
-               rabp = getblk(dev, rablkno);
-               if (rabp->b_flags & B_DONE)
+
+       /*
+        * If there's a read-ahead block, start i/o
+        * on it also (as above).
+        */
+       if (rablkno && !incore(vp, rablkno)) {
+               rabp = getblk(vp, rablkno, rabsize);
+#endif SECSIZE
+               if (rabp->b_flags & (B_DONE|B_DELWRI)) {

                        brelse(rabp);
                        brelse(rabp);

-               else {
+                       trace(TR_BREADHITRA,
+                           pack(vp->v_mount->m_fsid[0], rabsize), rablkno);
+               } else {

                        rabp->b_flags |= B_READ|B_ASYNC;
                        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 (rabp->b_bcount > rabp->b_bufsize)
+                               panic("breadrabp");
+                       if (rabp->b_rcred == NOCRED && cred != NOCRED) {
+                               crhold(cred);
+                               rabp->b_rcred = cred;
+                       }
+                       VOP_STRATEGY(rabp);
+                       trace(TR_BREADMISSRA,
+                           pack(vp->v_mount->m_fsid[0], rabsize), rablkno);
+                       u.u_ru.ru_inblock++;            /* pay in advance */

                }
        }
                }
        }

-       if(bp == NULL)
-               return(bread(dev, blkno));
-       iowait(bp);
-       return(bp);
+
+       /*
+        * If block was in core, let bread get it.
+        * If block wasn't in core, then the read was started
+        * above, and just wait for it.
+        */
+       if (bp == NULL)
+#ifdef SECSIZE
+               return (bread(dev, blkno, size, secsize));
+#else SECSIZE
+               return (bread(vp, blkno, size, cred, bpp));
+       return (biowait(bp));

 }
 
 /*
 }
 
 /*


@@ -164,26 +150,34 @@ daddr_t blkno, rablkno;
  * Then release the buffer.
  */
 bwrite(bp)
  * Then release the buffer.
  */
 bwrite(bp)

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

 {
 {

-       register flag;
+       register int flag;
+       int error;

 
        flag = bp->b_flags;
 
        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
+       bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI);

        if ((flag&B_DELWRI) == 0)
        if ((flag&B_DELWRI) == 0)

-               u.u_vm.vm_oublk++;              /* noone paid yet */
-       (*bdevsw[major(bp->b_dev)].d_strategy)(bp);
+               u.u_ru.ru_oublock++;            /* noone paid yet */
+       trace(TR_BWRITE,
+           pack(bp->b_vp->v_mount->m_fsid[0], bp->b_bcount), bp->b_lblkno);
+       if (bp->b_bcount > bp->b_bufsize)
+               panic("bwrite");
+       VOP_STRATEGY(bp);
+
+       /*
+        * If the write was synchronous, then await i/o completion.
+        * If the write was "delayed", then we put the buffer on
+        * the q of blocks awaiting i/o completion status.
+        */

        if ((flag&B_ASYNC) == 0) {
        if ((flag&B_ASYNC) == 0) {

-               iowait(bp);
+               error = biowait(bp);

                brelse(bp);
                brelse(bp);

-       } else if (flag & B_DELWRI)
+       } else if (flag & B_DELWRI) {

                bp->b_flags |= B_AGE;
                bp->b_flags |= B_AGE;

-       else
-               geterror(bp);
+               error = 0;
+       }
+       return (error);

 }
 
 /*
 }
 
 /*


@@ -195,16 +189,17 @@ register struct buf *bp;
  * in the same order as requested.
  */
 bdwrite(bp)
  * in the same order as requested.
  */
 bdwrite(bp)

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

 {
 {

-       register struct buf *dp;

 
        if ((bp->b_flags&B_DELWRI) == 0)
 
        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)
+               u.u_ru.ru_oublock++;            /* noone paid yet */
+       /*
+        * If this is a tape drive, the write must be initiated.
+        */
+       if (bdevsw[major(bp->b_dev)].d_flags & B_TAPE)

                bawrite(bp);
                bawrite(bp);

-       else {
+       } else {

                bp->b_flags |= B_DELWRI | B_DONE;
                brelse(bp);
        }
                bp->b_flags |= B_DELWRI | B_DONE;
                brelse(bp);
        }


@@ -214,47 +209,72 @@ register struct buf *bp;
  * Release the buffer, start I/O on it, but don't wait for completion.
  */
 bawrite(bp)
  * Release the buffer, start I/O on it, but don't wait for completion.
  */
 bawrite(bp)

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

 {
 
        bp->b_flags |= B_ASYNC;
 {
 
        bp->b_flags |= B_ASYNC;

-       bwrite(bp);
+       (void) bwrite(bp);

 }
 
 /*
 }
 
 /*

- * release the buffer, with no I/O implied.
+ * Release the buffer, with no I/O implied.

  */
 brelse(bp)
  */
 brelse(bp)

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

 {
 {

-       register struct buf **backp;
+       register struct buf *flist;

        register s;
 
        register s;
 

+       trace(TR_BRELSE,
+           pack(bp->b_vp->v_mount->m_fsid[0], bp->b_bufsize), bp->b_lblkno);
+       /*
+        * If a process is waiting for the buffer, or
+        * is waiting for a free buffer, awaken it.
+        */

        if (bp->b_flags&B_WANTED)
                wakeup((caddr_t)bp);
        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 (bfreelist[0].b_flags&B_WANTED) {
+               bfreelist[0].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 */
+       /*
+        * Retry I/O for locked buffers rather than invalidating them.
+        */
+       if ((bp->b_flags & B_ERROR) && (bp->b_flags & B_LOCKED))
+               bp->b_flags &= ~B_ERROR;
+
+       /*
+        * Disassociate buffers that are no longer valid.
+        */
+       if (bp->b_flags & (B_NOCACHE|B_ERROR))
+               bp->b_flags |= B_INVAL;
+       if ((bp->b_bufsize <= 0) || (bp->b_flags & (B_ERROR|B_INVAL))) {
+               if (bp->b_vp)
+                       brelvp(bp);
+               bp->b_flags &= ~B_DELWRI;

        }
        }

-       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;
+       /*
+        * Stick the buffer back on a free list.
+        */
+       s = splbio();
+       if (bp->b_bufsize <= 0) {
+               /* block has no buffer ... put at front of unused buffer list */
+               flist = &bfreelist[BQ_EMPTY];
+               binsheadfree(bp, flist);
+       } else if (bp->b_flags & (B_ERROR|B_INVAL)) {
+               /* block has no info ... put at front of most free list */
+               flist = &bfreelist[BQ_AGE];
+               binsheadfree(bp, flist);

        } else {
        } else {

-               backp = &bfreelist.av_back;
-               (*backp)->av_forw = bp;
-               bp->av_back = *backp;
-               *backp = bp;
-               bp->av_forw = &bfreelist;
+               if (bp->b_flags & B_LOCKED)
+                       flist = &bfreelist[BQ_LOCKED];
+               else if (bp->b_flags & B_AGE)
+                       flist = &bfreelist[BQ_AGE];
+               else
+                       flist = &bfreelist[BQ_LRU];
+               binstailfree(bp, flist);

        }
        }

-       bp->b_flags &= ~(B_WANTED|B_BUSY|B_ASYNC|B_AGE);
+       bp->b_flags &= ~(B_WANTED|B_BUSY|B_ASYNC|B_AGE|B_NOCACHE);

        splx(s);
 }
 
        splx(s);
 }
 


@@ -262,28 +282,39 @@ register struct buf *bp;
  * See if the block is associated with some buffer
  * (mainly to avoid getting hung up on a wait in breada)
  */
  * See if the block is associated with some buffer
  * (mainly to avoid getting hung up on a wait in breada)
  */

-incore(dev, blkno)
-dev_t dev;
-daddr_t blkno;
+incore(vp, blkno)
+       struct vnode *vp;
+       daddr_t blkno;

 {
        register struct buf *bp;
 {
        register struct buf *bp;

-       register int dblkno = fsbtodb(blkno);
+       register struct buf *dp;

 
 

-       for (bp = &buf[bufhash[BUFHASH(blkno)]]; bp != &buf[-1];
-           bp = &buf[bp->b_hlink])
-               if (bp->b_blkno == dblkno && bp->b_dev == dev)
+       dp = BUFHASH(vp, blkno);
+       for (bp = dp->b_forw; bp != dp; bp = bp->b_forw)
+               if (bp->b_lblkno == blkno && bp->b_vp == vp &&
+                   (bp->b_flags & B_INVAL) == 0)

                        return (1);
        return (0);
 }
 
                        return (1);
        return (0);
 }
 

-struct buf *
-baddr(dev, blkno)
-dev_t dev;
-daddr_t blkno;
+/*
+ * Return a block if it is in memory.
+ */
+baddr(vp, blkno, size, cred, bpp)
+       struct vnode *vp;
+       daddr_t blkno;
+       int size;
+       struct ucred *cred;
+       struct buf **bpp;
+#ifdef SECSIZE
+       long secsize;
+#endif SECSIZE

 {
 
 {
 

-       if (incore(dev, blkno))
-               return (bread(dev, blkno));
+       if (incore(vp, blkno))
+               return (bread(vp, blkno, size, cred, bpp));
+       *bpp = 0;
+#endif SECSIZE

        return (0);
 }
 
        return (0);
 }
 


@@ -291,93 +322,85 @@ daddr_t blkno;
  * Assign a buffer for the given block.  If the appropriate
  * block is already associated, return it; otherwise search
  * for the oldest non-busy buffer and reassign it.
  * Assign a buffer for the given block.  If the appropriate
  * block is already associated, return it; otherwise search
  * for the oldest non-busy buffer and reassign it.

+ *
+ * We use splx here because this routine may be called
+ * on the interrupt stack during a dump, and we don't
+ * want to lower the ipl back to 0.

  */
 struct buf *
  */
 struct buf *

-getblk(dev, blkno)
-dev_t dev;
-daddr_t blkno;
+#ifdef SECSIZE
+getblk(dev, blkno, size, secsize)
+#else SECSIZE
+getblk(vp, blkno, size)
+       register struct vnode *vp;
+       daddr_t blkno;
+       int size;
+#ifdef SECSIZE
+       long secsize;
+#endif SECSIZE

 {
 {

-       register struct buf *bp, *dp, *ep;
-       register int i, x;
-       register int dblkno = fsbtodb(blkno);
-
-    loop:
-       (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)
+       register struct buf *bp, *dp;
+       int s;
+
+       if (size > MAXBSIZE)
+               panic("getblk: size too big");
+       /*
+        * To prevent overflow of 32-bit ints when converting block
+        * numbers to byte offsets, blknos > 2^32 / DEV_BSIZE are set
+        * to the maximum number that can be converted to a byte offset
+        * without overflow. This is historic code; what bug it fixed,
+        * or whether it is still a reasonable thing to do is open to
+        * dispute. mkm 9/85
+        *
+        * Make it a panic to see if it ever really happens. mkm 11/89
+        */
+       if ((unsigned)blkno >= 1 << (sizeof(int)*NBBY-DEV_BSHIFT)) {
+               panic("getblk: blkno too big");
+               blkno = 1 << ((sizeof(int)*NBBY-DEV_BSHIFT) + 1);
+       }
+       /*
+        * Search the cache for the block.  If we hit, but
+        * the buffer is in use for i/o, then we wait until
+        * the i/o has completed.
+        */
+       dp = BUFHASH(vp, blkno);
+loop:
+       for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) {
+               if (bp->b_lblkno != blkno || bp->b_vp != vp ||
+                   bp->b_flags&B_INVAL)

                        continue;
                        continue;

-               (void) spl6();
+               s = splbio();

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

+                       splx(s);

                        goto loop;
                }
                        goto loop;
                }

-               (void) spl0();
-#ifdef DISKMON
-               i = 0;
-               dp = bp->av_forw;
-               while (dp != &bfreelist) {
-                       i++;
-                       dp = dp->av_forw;
-               }
-               if (i<NBUF)
-                       io_info.bufcount[i]++;
-#endif
+               splx(s);

                notavail(bp);
                notavail(bp);

+               if (bp->b_bcount != size) {
+                       printf("getblk: stray size");
+                       bp->b_flags |= B_INVAL;
+                       bwrite(bp);
+                       goto loop;
+               }

                bp->b_flags |= B_CACHE;
                bp->b_flags |= B_CACHE;

-               return(bp);
-       }
-       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;
+               return (bp);

        }
        }

-       spl0();
-       bp = bfreelist.av_forw;
-       notavail(bp);
-       if (bp->b_flags & B_DELWRI) {
-               bp->b_flags |= B_ASYNC;
-               bwrite(bp);
-               goto loop;
-       }
-       if (bp->b_dev == NODEV)
-               goto done;
-       /* INLINE EXPANSION OF bunhash(bp) */
-       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:
-       /* 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_forw = dp->b_forw;
-       bp->b_back = dp;
-       dp->b_forw->b_back = bp;
-       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);
+       bp = getnewbuf();
+       bfree(bp);
+       bremhash(bp);
+       bgetvp(vp, bp);
+       bp->b_lblkno = blkno;
+#ifdef SECSIZE
+       bp->b_blksize = secsize;
+#endif SECSIZE
+       bp->b_blkno = blkno;
+       bp->b_error = 0;
+       bp->b_resid = 0;
+       binshash(bp, dp);
+       brealloc(bp, size);
+       return (bp);

 }
 
 /*
 }
 
 /*


@@ -385,123 +408,135 @@ done:
  * not assigned to any particular device
  */
 struct buf *
  * not assigned to any particular device
  */
 struct buf *

-geteblk()
+geteblk(size)
+       int size;

 {
 {

-       register struct buf *bp, *dp;
-
-loop:
-       (void) spl6();
-       while (bfreelist.av_forw == &bfreelist) {
-               bfreelist.b_flags |= B_WANTED;
-               sleep((caddr_t)&bfreelist, PRIBIO+1);
-       }
-       (void) spl0();
-       dp = &bfreelist;
-       bp = bfreelist.av_forw;
-       notavail(bp);
-       if (bp->b_flags & B_DELWRI) {
-               bp->b_flags |= B_ASYNC;
-               bwrite(bp);
-               goto loop;
-       }
-       if (bp->b_dev != NODEV)
-               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_forw = dp->b_forw;
-       bp->b_back = dp;
-       dp->b_forw->b_back = bp;
-       dp->b_forw = bp;
-       bp->b_dev = (dev_t)NODEV;
-       bp->b_hlink = -1;
-       return(bp);
+       register struct buf *bp, *flist;
+
+       if (size > MAXBSIZE)
+               panic("geteblk: size too big");
+       bp = getnewbuf();
+       bp->b_flags |= B_INVAL;
+       bfree(bp);
+       bremhash(bp);
+       flist = &bfreelist[BQ_AGE];
+#ifdef SECSIZE
+       bp->b_blksize = DEV_BSIZE;
+#endif SECSIZE
+       bp->b_error = 0;
+       bp->b_resid = 0;
+       binshash(bp, flist);
+       brealloc(bp, size);
+       return (bp);

 }
 
 }
 

-bunhash(bp)
+/*
+ * Allocate space associated with a buffer.
+ */
+brealloc(bp, size)

        register struct buf *bp;
        register struct buf *bp;

+       int size;

 {
 {

+       daddr_t start, last;

        register struct buf *ep;
        register struct buf *ep;

-       register int i, x;
+       struct buf *dp;
+       int s;

 
 

-       if (bp->b_dev == NODEV)
-               return;
-       i = BUFHASH(dbtofsb(bp->b_blkno));
-       x = bp - buf;
-       if (bufhash[i] == x) {
-               bufhash[i] = bp->b_hlink;
+       if (size == bp->b_bcount)

                return;
                return;

-       }
-       for (ep = &buf[bufhash[i]]; ep != &buf[-1];
-           ep = &buf[ep->b_hlink])
-               if (ep->b_hlink == x) {
-                       ep->b_hlink = bp->b_hlink;
-                       return;
-               }
-       panic("bunhash");
+       allocbuf(bp, size);

 }
 
 /*
 }
 
 /*

- * Wait for I/O completion on the buffer; return errors
- * to the user.
+ * Find a buffer which is available for use.
+ * Select something from a free list.
+ * Preference is to AGE list, then LRU list.

  */
  */

-iowait(bp)
-register struct buf *bp;
+struct buf *
+getnewbuf()

 {
 {

+       register struct buf *bp, *dp;
+       register struct ucred *cred;
+       int s;

 
 

-       (void) spl6();
-       while ((bp->b_flags&B_DONE)==0)
-               sleep((caddr_t)bp, PRIBIO);
-       (void) spl0();
-       geterror(bp);
+loop:
+       s = splbio();
+       for (dp = &bfreelist[BQ_AGE]; dp > bfreelist; dp--)
+               if (dp->av_forw != dp)
+                       break;
+       if (dp == bfreelist) {          /* no free blocks */
+               dp->b_flags |= B_WANTED;
+               sleep((caddr_t)dp, PRIBIO+1);
+               splx(s);
+               goto loop;
+       }
+       splx(s);
+       bp = dp->av_forw;
+       notavail(bp);
+       if (bp->b_flags & B_DELWRI) {
+               (void) bawrite(bp);
+               goto loop;
+       }
+       trace(TR_BRELSE,
+           pack(bp->b_vp->v_mount->m_fsid[0], bp->b_bufsize), bp->b_lblkno);
+       if (bp->b_vp)
+               brelvp(bp);
+       if (bp->b_rcred != NOCRED) {
+               cred = bp->b_rcred;
+               bp->b_rcred = NOCRED;
+               crfree(cred);
+       }
+       if (bp->b_wcred != NOCRED) {
+               cred = bp->b_wcred;
+               bp->b_wcred = NOCRED;
+               crfree(cred);
+       }
+       bp->b_flags = B_BUSY;
+       return (bp);

 }
 
 }
 

-#ifndef FASTVAX

 /*
 /*

- * Unlink a buffer from the available list and mark it busy.
- * (internal interface)
+ * Wait for I/O completion on the buffer; return errors
+ * to the user.

  */
  */

-notavail(bp)
-register struct buf *bp;
+biowait(bp)
+       register struct buf *bp;

 {
 {

-       register s;
+       int s;

 
 

-       s = spl6();
-       bp->av_back->av_forw = bp->av_forw;
-       bp->av_forw->av_back = bp->av_back;
-       bp->b_flags |= B_BUSY;
+       s = splbio();
+       while ((bp->b_flags & B_DONE) == 0)
+               sleep((caddr_t)bp, PRIBIO);

        splx(s);
        splx(s);

+       /*
+        * Pick up the device's error number and pass it to the user;
+        * if there is an error but the number is 0 set a generalized code.
+        */
+       if ((bp->b_flags & B_ERROR) == 0)
+               return (0);
+       if (bp->b_error)
+               return (bp->b_error);
+       return (EIO);

 }
 }

-#endif

 
 /*
 
 /*

- * Mark I/O complete on a buffer. If the header
- * indicates a dirty page push completion, the
- * header is inserted into the ``cleaned'' list
- * to be processed by the pageout daemon. Otherwise
- * release it if I/O is asynchronous, and wake 
- * up anyone waiting for it.
+ * Mark I/O complete on a buffer.
+ * If someone should be called, e.g. the pageout
+ * daemon, do so.  Otherwise, wake up anyone
+ * waiting for it.

  */
  */

-iodone(bp)
-register struct buf *bp;
+biodone(bp)
+       register struct buf *bp;

 {
 {

-       register int s;

 
        if (bp->b_flags & B_DONE)
 
        if (bp->b_flags & B_DONE)

-               panic("dup iodone");
+               panic("dup biodone");

        bp->b_flags |= B_DONE;
        bp->b_flags |= B_DONE;

-       if (bp->b_flags & B_DIRTY) {
-               if (bp->b_flags & B_ERROR)
-                       panic("IO err in push");
-               s = spl6();
-               cnt.v_pgout++;
-               bp->av_forw = bclnlist;
-               bp->b_bcount = swsize[bp - swbuf];
-               bp->b_pfcent = swpf[bp - swbuf];
-               bclnlist = bp;
-               if (bswlist.b_flags & B_WANTED)
-                       wakeup((caddr_t)&proc[2]);
-               splx(s);
+       if ((bp->b_flags & B_READ) == 0)
+               bp->b_dirtyoff = bp->b_dirtyend = 0;
+       if (bp->b_flags & B_CALL) {
+               bp->b_flags &= ~B_CALL;
+               (*bp->b_iodone)(bp);

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


@@ -513,247 +548,287 @@ register struct buf *bp;
 }
 
 /*
 }
 
 /*

- * Zero the core associated with a buffer.
+ * Ensure that no part of a specified block is in an incore buffer.
+#ifdef SECSIZE
+ * "size" is given in device blocks (the units of b_lblkno).
+#endif SECSIZE
+#ifdef SECSIZE
+ * "size" is given in device blocks (the units of b_blkno).
+#endif SECSIZE

  */
  */

-clrbuf(bp)
-struct buf *bp;
+blkflush(vp, blkno, size)
+       struct vnode *vp;
+       daddr_t blkno;
+#ifdef SECSIZE
+       int size;
+#else SECSIZE
+       long size;
+#endif SECSIZE

 {
 {

-       register *p;
-       register c;
-
-       p = bp->b_un.b_words;
-       c = BSIZE/sizeof(int);
-       do
-               *p++ = 0;
-       while (--c);
-       bp->b_resid = 0;
+       register struct buf *ep;
+       struct buf *dp;
+       daddr_t curblk, nextblk, ecurblk, lastblk;
+       int s, error, allerrors = 0;
+
+       /*
+        * Iterate through each possible hash chain.
+        */
+       lastblk = blkno + btodb(size) - 1;
+       for (curblk = blkno; curblk <= lastblk; curblk = nextblk) {
+#if RND & (RND-1)
+               nextblk = ((curblk / RND) + 1) * RND;
+#else
+               nextblk = ((curblk & ~(RND-1)) + RND);
+#endif
+               ecurblk = nextblk > lastblk ? lastblk : nextblk - 1;
+               dp = BUFHASH(vp, curblk);
+loop:
+               for (ep = dp->b_forw; ep != dp; ep = ep->b_forw) {
+                       if (ep->b_vp != vp || (ep->b_flags & B_INVAL))
+                               continue;
+                       /* look for overlap */
+                       if (ep->b_bcount == 0 || ep->b_lblkno > ecurblk ||
+                           ep->b_lblkno + btodb(ep->b_bcount) <= curblk)
+                               continue;
+                       s = splbio();
+                       if (ep->b_flags&B_BUSY) {
+                               ep->b_flags |= B_WANTED;
+                               sleep((caddr_t)ep, PRIBIO+1);
+                               splx(s);
+                               goto loop;
+                       }
+                       if (ep->b_flags & B_DELWRI) {
+                               splx(s);
+                               notavail(ep);
+                               if (error = bwrite(ep))
+                                       allerrors = error;
+                               goto loop;
+                       }
+                       splx(s);
+               }
+       }
+       return (allerrors);

 }
 
 /*
 }
 
 /*

- * swap I/O -
- *
- * If the flag indicates a dirty page push initiated
- * by the pageout daemon, we map the page into the i th
- * virtual page of process 2 (the daemon itself) where i is
- * the index of the swap header that has been allocated.
- * We simply initialize the header and queue the I/O but
- * do not wait for completion. When the I/O completes,
- * iodone() will link the header to a list of cleaned
- * pages to be processed by the pageout daemon.
+ * Make sure all write-behind blocks associated
+ * with mount point are flushed out (from sync).

  */
  */

-swap(p, dblkno, addr, nbytes, rdflg, flag, dev, pfcent)
-       struct proc *p;
-       swblk_t dblkno;
-       caddr_t addr;
-       int flag, nbytes;
-       dev_t dev;
-       unsigned pfcent;
+mntflushbuf(mountp, flags)
+       struct mount *mountp;
+       int flags;
+{
+       register struct vnode *vp;
+       struct vnode *nvp;
+
+loop:
+       for (vp = mountp->m_mounth; vp; vp = nvp) {
+               nvp = vp->v_mountf;
+               if (vget(vp))
+                       goto loop;
+               vflushbuf(vp, flags);
+               vput(vp);
+       }
+}
+
+/*
+ * Flush all dirty buffers associated with a vnode.
+ */
+vflushbuf(vp, flags)
+       register struct vnode *vp;
+       int flags;

 {
        register struct buf *bp;
 {
        register struct buf *bp;

-       register int c;
-       int p2dp;
-       register struct pte *dpte, *vpte;
-
-       (void) spl6();
-       while (bswlist.av_forw == NULL) {
-               bswlist.b_flags |= B_WANTED;
-               sleep((caddr_t)&bswlist, PSWP+1);
+       struct buf *nbp;
+       int s;
+
+loop:
+       s = splbio();
+       for (bp = vp->v_blockh; bp; bp = nbp) {
+               nbp = bp->b_blockf;
+               if ((bp->b_flags & B_BUSY))
+                       continue;
+               if ((bp->b_flags & B_DELWRI) == 0)
+                       continue;
+               splx(s);
+               notavail(bp);
+               (void) bawrite(bp);
+               goto loop;

        }
        }

-       bp = bswlist.av_forw;
-       bswlist.av_forw = bp->av_forw;
-       (void) spl0();
-
-       bp->b_flags = B_BUSY | B_PHYS | rdflg | flag;
-       if ((bp->b_flags & (B_DIRTY|B_PGIN)) == 0)
-               if (rdflg == B_READ)
-                       sum.v_pswpin += btoc(nbytes);
-               else
-                       sum.v_pswpout += btoc(nbytes);
-       bp->b_proc = p;
-       if (flag & B_DIRTY) {
-               p2dp = ((bp - swbuf) * CLSIZE) * KLMAX;
-               dpte = dptopte(&proc[2], p2dp);
-               vpte = vtopte(p, btop(addr));
-               for (c = 0; c < nbytes; c += NBPG) {
-                       if (vpte->pg_pfnum == 0 || vpte->pg_fod)
-                               panic("swap bad pte");
-                       *dpte++ = *vpte++;
-               }
-               bp->b_un.b_addr = (caddr_t)ctob(p2dp);
-       } else
-               bp->b_un.b_addr = addr;
-       while (nbytes > 0) {
-               c = imin(ctob(120), nbytes);
-               bp->b_bcount = c;
-               bp->b_blkno = dblkno;
-               bp->b_dev = dev;
-               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");
-                       return;
+       splx(s);
+       if ((flags & B_SYNC) == 0)
+               return;
+wloop:
+       s = splbio();
+       for (bp = vp->v_blockh; bp; bp = nbp) {
+               nbp = bp->b_blockf;
+               if (bp->b_flags & B_BUSY) {
+                       bp->b_flags |= B_WANTED;
+                       sleep((caddr_t)bp, PRIBIO+1);
+                       splx(s);
+                       goto wloop;

                }
                }

-               (void) spl6();
-               while((bp->b_flags&B_DONE)==0)
-                       sleep((caddr_t)bp, PSWP);
-               (void) spl0();
-               bp->b_un.b_addr += c;
-               bp->b_flags &= ~B_DONE;
-               if (bp->b_flags & B_ERROR) {
-                       if ((flag & (B_UAREA|B_PAGET)) || rdflg == B_WRITE)
-                               panic("hard IO err in swap");
-                       swkill(p, (char *)0);
+               if ((bp->b_flags & B_DELWRI)) {
+                       splx(s);
+                       goto loop;

                }
                }

-               nbytes -= c;
-               dblkno += btoc(c);
-       }
-       (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;
-       if (bswlist.b_flags & B_WANTED) {
-               bswlist.b_flags &= ~B_WANTED;
-               wakeup((caddr_t)&bswlist);
-               wakeup((caddr_t)&proc[2]);

        }
        }

-       (void) spl0();
+       splx(s);

 }
 
 /*
 }
 
 /*

- * If rout == 0 then killed on swap error, else
- * rout is the name of the routine where we ran out of
- * swap space.
+ * Invalidate in core blocks belonging to closed or umounted filesystem
+ *
+ * Go through the list of vnodes associated with the file system;
+ * for each vnode invalidate any buffers that it holds. Normally
+ * this routine is preceeded by a bflush call, so that on a quiescent
+ * filesystem there will be no dirty buffers when we are done. Binval
+ * returns the count of dirty buffers when it is finished.

  */
  */

-swkill(p, rout)
-       struct proc *p;
-       char *rout;
+mntinvalbuf(mountp)
+       struct mount *mountp;

 {
 {

+       register struct vnode *vp;
+       struct vnode *nvp;
+       int dirty = 0;

 
 

-       printf("%d: ", p->p_pid);
-       if (rout)
-               printf("out of swap space in %s\n", rout);
-       else
-               printf("killed on swap error\n");
-       /*
-        * To be sure no looping (e.g. in vmsched trying to
-        * swap out) mark process locked in core (as though
-        * done by user) after killing it so noone will try
-        * to swap it out.
-        */
-       psignal(p, SIGKILL);
-       p->p_flag |= SULOCK;
+loop:
+       for (vp = mountp->m_mounth; vp; vp = nvp) {
+               nvp = vp->v_mountf;
+               if (vget(vp))
+                       goto loop;
+               dirty += vinvalbuf(vp, 1);
+               vput(vp);
+       }
+       return (dirty);

 }
 
 /*
 }
 
 /*

- * make sure all write-behind blocks
- * on dev (or NODEV for all)
- * are flushed out.
- * (from umount and update)
+ * Flush out and invalidate all buffers associated with a vnode.
+ * Called with the underlying object locked.

  */
  */

-bflush(dev)
-dev_t dev;
+vinvalbuf(vp, save)
+       register struct vnode *vp;
+       int save;

 {
        register struct buf *bp;
 {
        register struct buf *bp;

+       struct buf *nbp;
+       int s, dirty = 0;

 
 loop:
 
 loop:

-       (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;
-                       notavail(bp);
-                       bwrite(bp);
+       for (bp = vp->v_blockh; bp; bp = nbp) {
+               nbp = bp->b_blockf;
+               s = splbio();
+               if (bp->b_flags & B_BUSY) {
+                       bp->b_flags |= B_WANTED;
+                       sleep((caddr_t)bp, PRIBIO+1);
+                       splx(s);

                        goto loop;
                }
                        goto loop;
                }

+               splx(s);
+               notavail(bp);
+               if (save) {
+                       if (bp->b_flags & B_DELWRI) {
+                               dirty++;
+                               (void) bwrite(bp);
+                               goto loop;
+                       }
+               }
+               bp->b_flags |= B_INVAL;
+               brelse(bp);

        }
        }

-       (void) spl0();
+       if (vp->v_blockh != 0)
+               panic("vinvalbuf: flush failed");
+       return (dirty);

 }
 
 /*
 }
 
 /*

- * Raw I/O. The arguments are
- *     The strategy routine for the device
- *     A buffer, which will always be a special buffer
- *       header owned exclusively by the device for this purpose
- *     The device number
- *     Read/write flag
- * Essentially all the work is computing physical addresses and
- * validating them.
- * If the user has the proper access privilidges, the process is
- * marked 'delayed unlock' and the pages involved in the I/O are
- * faulted and locked. After the completion of the I/O, the above pages
- * are unlocked.
+ * Associate a buffer with a vnode.

  */
  */

-physio(strat, bp, dev, rw, mincnt)
-int (*strat)(); 
-register struct buf *bp;
-unsigned (*mincnt)();
+bgetvp(vp, bp)
+       register struct vnode *vp;
+       register struct buf *bp;

 {
 {

-       register int c;
-       char *a;

 
 

-       if (useracc(u.u_base,u.u_count,rw==B_READ?B_WRITE:B_READ) == NULL) {
-               u.u_error = EFAULT;
-               return;
-       }
-       (void) spl6();
-       while (bp->b_flags&B_BUSY) {
-               bp->b_flags |= B_WANTED;
-               sleep((caddr_t)bp, PRIBIO+1);
-       }
-       bp->b_error = 0;
-       bp->b_proc = u.u_procp;
-       bp->b_un.b_addr = u.u_base;
-       while (u.u_count != 0 && bp->b_error==0) {
-               bp->b_flags = B_BUSY | B_PHYS | rw;
-               bp->b_dev = dev;
-               bp->b_blkno = u.u_offset >> PGSHIFT;
-               bp->b_bcount = u.u_count;
-               (*mincnt)(bp);
-               c = bp->b_bcount;
-               u.u_procp->p_flag |= SPHYSIO;
-               vslock(a = bp->b_un.b_addr, c);
-               (*strat)(bp);
-               (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);
-               (void) spl0();
-               bp->b_un.b_addr += c;
-               u.u_count -= c;
-               u.u_offset += c;
+       if (bp->b_vp)
+               panic("bgetvp: not free");
+       VREF(vp);
+       bp->b_vp = vp;
+       if (vp->v_type == VBLK || vp->v_type == VCHR)
+               bp->b_dev = vp->v_rdev;
+       else
+               bp->b_dev = NODEV;
+       /*
+        * Insert onto list for new vnode.
+        */
+       if (vp->v_blockh) {
+               bp->b_blockf = vp->v_blockh;
+               bp->b_blockb = &vp->v_blockh;
+               vp->v_blockh->b_blockb = &bp->b_blockf;
+               vp->v_blockh = bp;
+       } else {
+               vp->v_blockh = bp;
+               bp->b_blockb = &vp->v_blockh;
+               bp->b_blockf = NULL;

        }
        }

-       bp->b_flags &= ~(B_BUSY|B_WANTED|B_PHYS);
-       u.u_count = bp->b_resid;
-       geterror(bp);

 }
 
 }
 

-/*ARGSUSED*/
-unsigned
-minphys(bp)
-struct buf *bp;
+/*
+ * Disassociate a buffer from a vnode.
+ */
+brelvp(bp)
+       register struct buf *bp;

 {
 {

+       struct buf *bq;
+       struct vnode *vp;

 
 

-       if (bp->b_bcount > 60 * 1024)
-               bp->b_bcount = 60 * 1024;
+       if (bp->b_vp == (struct vnode *) 0)
+               panic("brelvp: NULL");
+       /*
+        * Delete from old vnode list, if on one.
+        */
+       if (bp->b_blockb) {
+               if (bq = bp->b_blockf)
+                       bq->b_blockb = bp->b_blockb;
+               *bp->b_blockb = bq;
+               bp->b_blockf = NULL;
+               bp->b_blockb = NULL;
+       }
+       vp = bp->b_vp;
+       bp->b_vp = (struct vnode *) 0;
+       vrele(vp);

 }
 
 /*
 }
 
 /*

- * Pick up the device's error number and pass it to the user;
- * if there is an error but the number is 0 set a generalized
- * code.  Actually the latter is always true because devices
- * don't yet return specific errors.
+ * Reassign a buffer from one vnode to another.
+ * Used to assign file specific control information
+ * (indirect blocks) to the vnode to which they belong.

  */
  */

-geterror(bp)
-register struct buf *bp;
+reassignbuf(bp, newvp)
+       register struct buf *bp;
+       register struct vnode *newvp;

 {
 {

+       register struct buf *bq;

 
 

-       if (bp->b_flags&B_ERROR)
-               if ((u.u_error = bp->b_error)==0)
-                       u.u_error = EIO;
+       /*
+        * Delete from old vnode list, if on one.
+        */
+       if (bp->b_blockb) {
+               if (bq = bp->b_blockf)
+                       bq->b_blockb = bp->b_blockb;
+               *bp->b_blockb = bq;
+       }
+       /*
+        * Insert onto list for new vnode.
+        */
+       if (newvp->v_blockh) {
+               bp->b_blockf = newvp->v_blockh;
+               bp->b_blockb = &newvp->v_blockh;
+               newvp->v_blockh->b_blockb = &bp->b_blockf;
+               newvp->v_blockh = bp;
+       } else {
+               newvp->v_blockh = bp;
+               bp->b_blockb = &newvp->v_blockh;
+               bp->b_blockf = NULL;
+       }

 }
 }