BSD 4_4_Lite1 release

[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 4f66c4e..ec5c962 100644 (file)
--- a/usr/src/sys/kern/vfs_bio.c
+++ b/usr/src/sys/kern/vfs_bio.c
@@ -1,639 +1,339 @@
 /*-
 /*-

- * Copyright (c) 1982, 1986, 1989 The Regents of the University of California.
- * All rights reserved.
+ * Copyright (c) 1982, 1986, 1989, 1993
+ *     The Regents of the University of California.  All rights reserved.
+ * (c) UNIX System Laboratories, Inc.
+ * All or some portions of this file are derived from material licensed
+ * to the University of California by American Telephone and Telegraph
+ * Co. or Unix System Laboratories, Inc. and are reproduced herein with
+ * the permission of UNIX System Laboratories, Inc.

  *
  *

- * This module is believed to contain source code proprietary to AT&T.
- * Use and redistribution is subject to the Berkeley Software License
- * Agreement and your Software Agreement with AT&T (Western Electric).
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *     This product includes software developed by the University of
+ *     California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.

  *
  *

- *     @(#)vfs_bio.c   7.50 (Berkeley) %G%
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *     from: @(#)vfs_bio.c     8.6 (Berkeley) 1/11/94

  */
 
 #include <sys/param.h>
  */
 
 #include <sys/param.h>

+#include <sys/systm.h>

 #include <sys/proc.h>
 #include <sys/buf.h>
 #include <sys/vnode.h>
 #include <sys/proc.h>
 #include <sys/buf.h>
 #include <sys/vnode.h>

-#include <sys/specdev.h>

 #include <sys/mount.h>
 #include <sys/trace.h>
 #include <sys/mount.h>
 #include <sys/trace.h>

+#include <sys/malloc.h>

 #include <sys/resourcevar.h>
 
 #include <sys/resourcevar.h>
 

+/*
+ * Definitions for the buffer hash lists.
+ */
+#define        BUFHASH(dvp, lbn)       \
+       (&bufhashtbl[((int)(dvp) / sizeof(*(dvp)) + (int)(lbn)) & bufhash])
+LIST_HEAD(bufhashhdr, buf) *bufhashtbl, invalhash;
+u_long bufhash;
+
+/*
+ * Insq/Remq for the buffer hash lists.
+ */
+#define        binshash(bp, dp)        LIST_INSERT_HEAD(dp, bp, b_hash)
+#define        bremhash(bp)            LIST_REMOVE(bp, b_hash)
+
+/*
+ * Definitions for the buffer free lists.
+ */
+#define        BQUEUES         4               /* number of free buffer queues */
+
+#define        BQ_LOCKED       0               /* super-blocks &c */
+#define        BQ_LRU          1               /* lru, useful buffers */
+#define        BQ_AGE          2               /* rubbish */
+#define        BQ_EMPTY        3               /* buffer headers with no memory */
+
+TAILQ_HEAD(bqueues, buf) bufqueues[BQUEUES];
+int needbuffer;
+
+/*
+ * Insq/Remq for the buffer free lists.
+ */
+#define        binsheadfree(bp, dp)    TAILQ_INSERT_HEAD(dp, bp, b_freelist)
+#define        binstailfree(bp, dp)    TAILQ_INSERT_TAIL(dp, bp, b_freelist)
+
+void
+bremfree(bp)
+       struct buf *bp;
+{
+       struct bqueues *dp = NULL;
+
+       /*
+        * We only calculate the head of the freelist when removing
+        * the last element of the list as that is the only time that
+        * it is needed (e.g. to reset the tail pointer).
+        *
+        * NB: This makes an assumption about how tailq's are implemented.
+        */
+       if (bp->b_freelist.tqe_next == NULL) {
+               for (dp = bufqueues; dp < &bufqueues[BQUEUES]; dp++)
+                       if (dp->tqh_last == &bp->b_freelist.tqe_next)
+                               break;
+               if (dp == &bufqueues[BQUEUES])
+                       panic("bremfree: lost tail");
+       }
+       TAILQ_REMOVE(dp, bp, b_freelist);
+}
+

 /*
  * Initialize buffers and hash links for buffers.
  */
 void
 bufinit()
 {
 /*
  * Initialize buffers and hash links for buffers.
  */
 void
 bufinit()
 {

+       register struct buf *bp;
+       struct bqueues *dp;

        register int i;
        register int i;

-       register struct buf *bp, *dp;
-       register struct bufhd *hp;

        int base, residual;
 
        int base, residual;
 

-       for (hp = bufhash, i = 0; i < BUFHSZ; i++, hp++)
-               hp->b_forw = hp->b_back = (struct buf *)hp;
-
-       for (dp = bfreelist; dp < &bfreelist[BQUEUES]; dp++) {
-               dp->b_forw = dp->b_back = dp->av_forw = dp->av_back = dp;
-               dp->b_flags = B_HEAD;
-       }
+       for (dp = bufqueues; dp < &bufqueues[BQUEUES]; dp++)
+               TAILQ_INIT(dp);
+       bufhashtbl = hashinit(nbuf, M_CACHE, &bufhash);

        base = bufpages / nbuf;
        residual = bufpages % nbuf;
        for (i = 0; i < nbuf; i++) {
                bp = &buf[i];
        base = bufpages / nbuf;
        residual = bufpages % nbuf;
        for (i = 0; i < nbuf; i++) {
                bp = &buf[i];

+               bzero((char *)bp, sizeof *bp);

                bp->b_dev = NODEV;
                bp->b_dev = NODEV;

-               bp->b_bcount = 0;

                bp->b_rcred = NOCRED;
                bp->b_wcred = NOCRED;
                bp->b_rcred = NOCRED;
                bp->b_wcred = NOCRED;

-               bp->b_dirtyoff = 0;
-               bp->b_dirtyend = 0;
-               bp->b_validoff = 0;
-               bp->b_validend = 0;
-               bp->b_un.b_addr = buffers + i * MAXBSIZE;
+               bp->b_vnbufs.le_next = NOLIST;
+               bp->b_data = buffers + i * MAXBSIZE;

                if (i < residual)
                        bp->b_bufsize = (base + 1) * CLBYTES;
                else
                        bp->b_bufsize = base * CLBYTES;
                if (i < residual)
                        bp->b_bufsize = (base + 1) * CLBYTES;
                else
                        bp->b_bufsize = base * CLBYTES;

-               binshash(bp, &bfreelist[BQ_AGE]);

                bp->b_flags = B_INVAL;
                bp->b_flags = B_INVAL;

-               dp = bp->b_bufsize ? &bfreelist[BQ_AGE] : &bfreelist[BQ_EMPTY];
+               dp = bp->b_bufsize ? &bufqueues[BQ_AGE] : &bufqueues[BQ_EMPTY];

                binsheadfree(bp, dp);
                binsheadfree(bp, dp);

+               binshash(bp, &invalhash);

        }
 }
 
        }
 }
 

-/*
- * Find the block in the buffer pool.
- * If the buffer is not present, allocate a new buffer and load
- * its contents according to the filesystem fill routine.
- */
-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
+bread(a1, a2, a3, a4, a5)
+       struct vnode *a1;
+       daddr_t a2;
+       int a3;
+       struct ucred *a4;
+       struct buf **a5;

 {
 {

-       struct proc *p = curproc;               /* XXX */
-       register struct buf *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, size), blkno);
-               return (0);
-       }
-       bp->b_flags |= B_READ;
-       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, size), blkno);
-       p->p_stats->p_ru.ru_inblock++;          /* pay for read */
-       return (biowait(bp));
-}
-
-/*
- * Operates like bread, but also starts I/O on the N specified
- * read-ahead blocks.
- */
-breadn(vp, blkno, size, rablkno, rabsize, num, cred, bpp)
-       struct vnode *vp;
-       daddr_t blkno; int size;
-#ifdef SECSIZE
-       long secsize;
-#endif SECSIZE
-       daddr_t rablkno[]; int rabsize[];
-       int num;
-       struct ucred *cred;
-       struct buf **bpp;
-{
-       struct proc *p = curproc;               /* XXX */
-       register struct buf *bp, *rabp;
-       register int i;

 
 

-       bp = NULL;

        /*
        /*

-        * If the block is not memory resident,
-        * allocate a buffer and start I/O.
+        * Body deleted.

         */
         */

-       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;
-                       if (bp->b_bcount > bp->b_bufsize)
-                               panic("breadn");
-                       if (bp->b_rcred == NOCRED && cred != NOCRED) {
-                               crhold(cred);
-                               bp->b_rcred = cred;
-                       }
-                       VOP_STRATEGY(bp);
-                       trace(TR_BREADMISS, pack(vp, size), blkno);
-                       p->p_stats->p_ru.ru_inblock++;  /* pay for read */
-               } else {
-                       trace(TR_BREADHIT, pack(vp, size), blkno);
-               }
-       }
+       return (EIO);
+}

 
 

-       /*
-        * If there's read-ahead block(s), start I/O
-        * on them also (as above).
-        */
-       for (i = 0; i < num; i++) {
-               if (incore(vp, rablkno[i]))
-                       continue;
-               rabp = getblk(vp, rablkno[i], rabsize[i]);
-#endif SECSIZE
-               if (rabp->b_flags & (B_DONE | B_DELWRI)) {
-                       brelse(rabp);
-                       trace(TR_BREADHITRA, pack(vp, rabsize[i]), rablkno[i]);
-               } else {
-                       rabp->b_flags |= B_ASYNC | B_READ;
-                       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, rabsize[i]), rablkno[i]);
-                       p->p_stats->p_ru.ru_inblock++;  /* pay in advance */
-               }
-       }
+breadn(a1, a2, a3, a4, a5, a6, a7, a8)
+       struct vnode *a1;
+       daddr_t a2; int a3;
+       daddr_t a4[]; int a5[];
+       int a6;
+       struct ucred *a7;
+       struct buf **a8;
+{

 
        /*
 
        /*

-        * If block was memory resident, let bread get it.
-        * If block was not memory resident, the read was
-        * started above, so just wait for the read to complete.
+        * Body deleted.

         */
         */

-       if (bp == NULL)
-#ifdef SECSIZE
-               return (bread(dev, blkno, size, secsize));
-#else SECSIZE
-               return (bread(vp, blkno, size, cred, bpp));
-       return (biowait(bp));
+       return (EIO);

 }
 
 }
 

-/*
- * Synchronous write.
- * Release buffer on completion.
- */
-bwrite(bp)
-       register struct buf *bp;
+bwrite(a1)
+       struct buf *a1;

 {
 {

-       struct proc *p = curproc;               /* XXX */
-       register int flag;
-       int s, error = 0;
-
-       flag = bp->b_flags;
-       bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI);
-       if (flag & B_ASYNC) {
-               if ((flag & B_DELWRI) == 0)
-                       p->p_stats->p_ru.ru_oublock++;  /* no one paid yet */
-               else
-                       reassignbuf(bp, bp->b_vp);
-       }
-       trace(TR_BWRITE, pack(bp->b_vp, bp->b_bcount), bp->b_lblkno);
-       if (bp->b_bcount > bp->b_bufsize)
-               panic("bwrite");
-       s = splbio();
-       bp->b_vp->v_numoutput++;
-       splx(s);
-       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 queue of blocks awaiting I/O completion status.
+        * Body deleted.

         */
         */

-       if ((flag & B_ASYNC) == 0) {
-               error = biowait(bp);
-               if ((flag&B_DELWRI) == 0)
-                       p->p_stats->p_ru.ru_oublock++;  /* no one paid yet */
-               else
-                       reassignbuf(bp, bp->b_vp);
-               brelse(bp);
-       } else if (flag & B_DELWRI) {
-               s = splbio();
-               bp->b_flags |= B_AGE;
-               splx(s);
-       }
-       return (error);
+       return (EIO);

 }
 
 int
 vn_bwrite(ap)
        struct vop_bwrite_args *ap;
 {
 }
 
 int
 vn_bwrite(ap)
        struct vop_bwrite_args *ap;
 {

-       return bwrite (ap->a_bp);
+       return (bwrite(ap->a_bp));

 }
 
 }
 

-
-/*
- * Delayed write.
- *
- * The buffer is marked dirty, but is not queued for I/O.
- * This routine should be used when the buffer is expected
- * to be modified again soon, typically a small write that
- * partially fills a buffer.
- *
- * NB: magnetic tapes cannot be delayed; they must be
- * written in the order that the writes are requested.
- */
-bdwrite(bp)
-       register struct buf *bp;
+bdwrite(a1)
+       struct buf *a1;

 {
 {

-       struct proc *p = curproc;               /* XXX */

 
 

-       if ((bp->b_flags & B_DELWRI) == 0) {
-               bp->b_flags |= B_DELWRI;
-               reassignbuf(bp, bp->b_vp);
-               p->p_stats->p_ru.ru_oublock++;          /* no one paid yet */
-       }

        /*
        /*

-        * If this is a tape drive, the write must be initiated.
+        * Body deleted.

         */
         */

-       if (bdevsw[major(bp->b_dev)].d_flags & B_TAPE)
-               bawrite(bp);
-       } else {
-               bp->b_flags |= (B_DONE | B_DELWRI);
-               brelse(bp);
-       }
+       return;

 }
 
 }
 

-/*
- * Asynchronous write.
- * Start I/O on a buffer, but do not wait for it to complete.
- * The buffer is released when the I/O completes.
- */
-bawrite(bp)
-       register struct buf *bp;
+bawrite(a1)
+       struct buf *a1;

 {
 
        /*
 {
 
        /*

-        * Setting the ASYNC flag causes bwrite to return
-        * after starting the I/O.
+        * Body deleted.

         */
         */

-       bp->b_flags |= B_ASYNC;
-       (void) bwrite(bp);
+       return;

 }
 
 }
 

-/*
- * Release a buffer.
- * Even if the buffer is dirty, no I/O is started.
- */
-brelse(bp)
-       register struct buf *bp;
+brelse(a1)
+       struct buf *a1;

 {
 {

-       register struct buf *flist;
-       int s;

 
 

-       trace(TR_BRELSE, pack(bp->b_vp, 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 (bfreelist[0].b_flags & B_WANTED) {
-               bfreelist[0].b_flags &= ~B_WANTED;
-               wakeup((caddr_t)bfreelist);
-       }

        /*
        /*

-        * Retry I/O for locked buffers rather than invalidating them.
+        * Body deleted.

         */
         */

-       s = splbio();
-       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;
-       }
-       /*
-        * Stick the buffer back on a free list.
-        */
-       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 {
-               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 | B_NOCACHE);
-       splx(s);
+       return;

 }
 
 }
 

-/*
- * Check to see if a block is currently memory resident.
- */
-incore(vp, blkno)
-       struct vnode *vp;
-       daddr_t blkno;
+struct buf *
+incore(a1, a2)
+       struct vnode *a1;
+       daddr_t a2;

 {
 {

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

 
 

-       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);
+       /*
+        * Body deleted.
+        */

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

-/*
- * Check to see if a block is currently memory resident.
- * If it is resident, return it. If it is not resident,
- * allocate a new buffer and assign it to the block.
- */

 struct buf *
 struct buf *

-#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
+getblk(a1, a2, a3, a4, a5)
+       struct vnode *a1;
+       daddr_t a2;
+       int a3, a4, a5;

 {
 {

-       register struct buf *bp, *dp;
-       int s;

 
 

-       if (size > MAXBSIZE)
-               panic("getblk: size too big");

        /*
        /*

-        * Search the cache for the block. If the buffer is found,
-        * but it is currently locked, the we must wait for it to
-        * become available.
+        * Body deleted.

         */
         */

-       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;
-               s = splbio();
-               if (bp->b_flags & B_BUSY) {
-                       bp->b_flags |= B_WANTED;
-                       sleep((caddr_t)bp, PRIBIO + 1);
-                       splx(s);
-                       goto loop;
-               }
-               bremfree(bp);
-               bp->b_flags |= B_BUSY;
-               splx(s);
-               if (bp->b_bcount != size) {
-                       printf("getblk: stray size");
-                       bp->b_flags |= B_INVAL;
-                       bwrite(bp);
-                       goto loop;
-               }
-               bp->b_flags |= B_CACHE;
-               return (bp);
-       }
-       bp = getnewbuf();
-       bremhash(bp);
-       bgetvp(vp, bp);
-       bp->b_bcount = 0;
-       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);
-       allocbuf(bp, size);
-       return (bp);
+       return ((struct buf *)0);

 }
 
 }
 

-/*
- * Allocate a buffer.
- * The caller will assign it to a block.
- */

 struct buf *
 struct buf *

-geteblk(size)
-       int size;
+geteblk(a1)
+       int a1;

 {
 {

-       register struct buf *bp, *flist;
-
-       if (size > MAXBSIZE)
-               panic("geteblk: size too big");
-       bp = getnewbuf();
-       bp->b_flags |= B_INVAL;
-       bremhash(bp);
-       flist = &bfreelist[BQ_AGE];
-       bp->b_bcount = 0;
-#ifdef SECSIZE
-       bp->b_blksize = DEV_BSIZE;
-#endif SECSIZE
-       bp->b_error = 0;
-       bp->b_resid = 0;
-       binshash(bp, flist);
-       allocbuf(bp, size);
-       return (bp);
+
+       /*
+        * Body deleted.
+        */
+       return ((struct buf *)0);

 }
 
 }
 

-/*
- * Expand or contract the actual memory allocated to a buffer.
- * If no memory is available, release buffer and take error exit.
- */
-allocbuf(tp, size)
-       register struct buf *tp;
-       int size;
+allocbuf(a1, a2)
+       struct buf *a1;
+       int a2;

 {
 {

-       register struct buf *bp, *ep;
-       int sizealloc, take, s;

 
 

-       sizealloc = roundup(size, CLBYTES);

        /*
        /*

-        * Buffer size does not change
+        * Body deleted.

         */
         */

-       if (sizealloc == tp->b_bufsize)
-               goto out;
+       return (0);
+}
+
+struct buf *
+getnewbuf(a1, a2)
+       int a1, a2;
+{
+

        /*
        /*

-        * Buffer size is shrinking.
-        * Place excess space in a buffer header taken from the
-        * BQ_EMPTY buffer list and placed on the "most free" list.
-        * If no extra buffer headers are available, leave the
-        * extra space in the present buffer.
+        * Body deleted.

         */
         */

-       if (sizealloc < tp->b_bufsize) {
-               ep = bfreelist[BQ_EMPTY].av_forw;
-               if (ep == &bfreelist[BQ_EMPTY])
-                       goto out;
-               s = splbio();
-               bremfree(ep);
-               ep->b_flags |= B_BUSY;
-               splx(s);
-               pagemove(tp->b_un.b_addr + sizealloc, ep->b_un.b_addr,
-                   (int)tp->b_bufsize - sizealloc);
-               ep->b_bufsize = tp->b_bufsize - sizealloc;
-               tp->b_bufsize = sizealloc;
-               ep->b_flags |= B_INVAL;
-               ep->b_bcount = 0;
-               brelse(ep);
-               goto out;
-       }
+       return ((struct buf *)0);
+}
+
+biowait(a1)
+       struct buf *a1;
+{
+

        /*
        /*

-        * More buffer space is needed. Get it out of buffers on
-        * the "most free" list, placing the empty headers on the
-        * BQ_EMPTY buffer header list.
+        * Body deleted.

         */
         */

-       while (tp->b_bufsize < sizealloc) {
-               take = sizealloc - tp->b_bufsize;
-               bp = getnewbuf();
-               if (take >= bp->b_bufsize)
-                       take = bp->b_bufsize;
-               pagemove(&bp->b_un.b_addr[bp->b_bufsize - take],
-                   &tp->b_un.b_addr[tp->b_bufsize], take);
-               tp->b_bufsize += take;
-               bp->b_bufsize = bp->b_bufsize - take;
-               if (bp->b_bcount > bp->b_bufsize)
-                       bp->b_bcount = bp->b_bufsize;
-               if (bp->b_bufsize <= 0) {
-                       bremhash(bp);
-                       binshash(bp, &bfreelist[BQ_EMPTY]);
-                       bp->b_dev = NODEV;
-                       bp->b_error = 0;
-                       bp->b_flags |= B_INVAL;
-               }
-               brelse(bp);
-       }
-out:
-       tp->b_bcount = size;
-       return (1);
+       return (EIO);

 }
 
 }
 

-/*
- * Find a buffer which is available for use.
- * Select something from a free list.
- * Preference is to AGE list, then LRU list.
- */
-struct buf *
-getnewbuf()
+void
+biodone(a1)
+       struct buf *a1;

 {
 {

-       register struct buf *bp, *dp;
-       register struct ucred *cred;
-       int s;
-
-#ifdef LFS
-       lfs_flush();
-#endif
-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;
-       }
-       bp = dp->av_forw;
-       bremfree(bp);
-       bp->b_flags |= B_BUSY;
-       splx(s);
-       if (bp->b_flags & B_DELWRI) {
-               (void) bawrite(bp);
-               goto loop;
-       }
-       trace(TR_BRELSE, pack(bp->b_vp, 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;
-       bp->b_dirtyoff = bp->b_dirtyend = 0;
-       bp->b_validoff = bp->b_validend = 0;
-       return (bp);
+
+       /*
+        * Body deleted.
+        */
+       return;

 }
 
 }
 

-/*
- * Wait for I/O to complete.
- *
- * Extract and return any errors associated with the I/O.
- * If the error flag is set, but no specific error is
- * given, return EIO.
- */
-biowait(bp)
-       register struct buf *bp;
+int
+count_lock_queue()

 {
 {

-       int s;
-
-       s = splbio();
-       while ((bp->b_flags & B_DONE) == 0)
-               sleep((caddr_t)bp, PRIBIO);
-       splx(s);
-       if ((bp->b_flags & B_ERROR) == 0)
-               return (0);
-       if (bp->b_error)
-               return (bp->b_error);
-       return (EIO);
+
+       /*
+        * Body deleted.
+        */
+       return (0);

 }
 
 }
 

+#ifdef DIAGNOSTIC

 /*
 /*

- * Mark I/O complete on a buffer.
- *
- * If a callback has been requested, e.g. the pageout
- * daemon, do so. Otherwise, awaken waiting processes.
+ * Print out statistics on the current allocation of the buffer pool.
+ * Can be enabled to print out on every ``sync'' by setting "syncprt"
+ * in vfs_syscalls.c using sysctl.

  */
 void
  */
 void

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

 {
 {

-
-       if (bp->b_flags & B_DONE)
-               panic("dup biodone");
-       bp->b_flags |= B_DONE;
-       if ((bp->b_flags & B_READ) == 0)
-               vwakeup(bp);
-       if (bp->b_flags & B_CALL) {
-               bp->b_flags &= ~B_CALL;
-               (*bp->b_iodone)(bp);
-               return;
-       }
-       if (bp->b_flags & B_ASYNC)
-               brelse(bp);
-       else {
-               bp->b_flags &= ~B_WANTED;
-               wakeup((caddr_t)bp);
+       int s, i, j, count;
+       register struct buf *bp;
+       register struct bqueues *dp;
+       int counts[MAXBSIZE/CLBYTES+1];
+       static char *bname[BQUEUES] = { "LOCKED", "LRU", "AGE", "EMPTY" };
+
+       for (dp = bufqueues, i = 0; dp < &bufqueues[BQUEUES]; dp++, i++) {
+               count = 0;
+               for (j = 0; j <= MAXBSIZE/CLBYTES; j++)
+                       counts[j] = 0;
+               s = splbio();
+               for (bp = dp->tqh_first; bp; bp = bp->b_freelist.tqe_next) {
+                       counts[bp->b_bufsize/CLBYTES]++;
+                       count++;
+               }
+               splx(s);
+               printf("%s: total-%d", bname[i], count);
+               for (j = 0; j <= MAXBSIZE/CLBYTES; j++)
+                       if (counts[j] != 0)
+                               printf(", %d-%d", j * CLBYTES, counts[j]);
+               printf("\n");

        }
 }
        }
 }

+#endif /* DIAGNOSTIC */