convert VOP_UNLOCK and vrele into vput's; add proc parameter to union_dircache

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

diff --git a/usr/src/sys/kern/vfs_cluster.c b/usr/src/sys/kern/vfs_cluster.c
index 7a83a48..e6b6b9a 100644 (file)
--- a/usr/src/sys/kern/vfs_cluster.c
+++ b/usr/src/sys/kern/vfs_cluster.c
@@ -1,761 +1,742 @@
-/*
- * Copyright (c) 1982, 1986, 1989 Regents of the University of California.
- * All rights reserved.
+/*-
+ * Copyright (c) 1993
+ *     The 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.
+ * %sccs.include.redist.c%

  *
  *

- *     @(#)vfs_cluster.c       7.8 (Berkeley) %G%
+ *     @(#)vfs_cluster.c       8.10 (Berkeley) %G%

  */
 
  */
 

-#include "param.h"
-#include "user.h"
-#include "buf.h"
-#include "vnode.h"
-#include "trace.h"
+#include <sys/param.h>
+#include <sys/proc.h>
+#include <sys/buf.h>
+#include <sys/vnode.h>
+#include <sys/mount.h>
+#include <sys/trace.h>
+#include <sys/malloc.h>
+#include <sys/resourcevar.h>
+#include <libkern/libkern.h>
+#include <ufs/ufs/quota.h>
+#include <ufs/ufs/inode.h>

 
 /*
 
 /*

- * Read in (if necessary) the block and return a buffer pointer.
+ * Local declarations

  */
  */

-bread(vp, blkno, size, bpp)
-       struct vnode *vp;
-       daddr_t blkno;
-       int size;
-       struct buf **bpp;
-#ifdef SECSIZE
-       long secsize;
-#endif SECSIZE
-{
-       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->v_mount->m_fsid[0], size), blkno);
-               return (0);
-       }
-       bp->b_flags |= B_READ;
-       if (bp->b_bcount > bp->b_bufsize)
-               panic("bread");
-       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));
-}
+struct buf *cluster_newbuf __P((struct vnode *, struct buf *, long, daddr_t,
+           daddr_t, long, int));
+struct buf *cluster_rbuild __P((struct vnode *, u_quad_t, struct buf *,
+           daddr_t, daddr_t, long, int, long));
+void       cluster_wbuild __P((struct vnode *, struct buf *, long,
+           daddr_t, int, daddr_t));
+struct cluster_save *cluster_collectbufs __P((struct vnode *, struct buf *));
+
+#ifdef DIAGNOSTIC
+/*
+ * Set to 1 if reads of block zero should cause readahead to be done.
+ * Set to 0 treats a read of block zero as a non-sequential read.
+ *
+ * Setting to one assumes that most reads of block zero of files are due to
+ * sequential passes over the files (e.g. cat, sum) where additional blocks
+ * will soon be needed.  Setting to zero assumes that the majority are
+ * surgical strikes to get particular info (e.g. size, file) where readahead
+ * blocks will not be used and, in fact, push out other potentially useful
+ * blocks from the cache.  The former seems intuitive, but some quick tests
+ * showed that the latter performed better from a system-wide point of view.
+ */
+int    doclusterraz = 0;
+#define ISSEQREAD(vp, blk) \
+       (((blk) != 0 || doclusterraz) && \
+        ((blk) == (vp)->v_lastr + 1 || (blk) == (vp)->v_lastr))
+#else
+#define ISSEQREAD(vp, blk) \
+       ((blk) != 0 && ((blk) == (vp)->v_lastr + 1 || (blk) == (vp)->v_lastr))
+#endif

 
 /*
 
 /*

- * Read in the block, like bread, but also start I/O on the
- * read-ahead block (which is not allocated to the caller)
+ * This replaces bread.  If this is a bread at the beginning of a file and
+ * lastr is 0, we assume this is the first read and we'll read up to two
+ * blocks if they are sequential.  After that, we'll do regular read ahead
+ * in clustered chunks.
+ *
+ * There are 4 or 5 cases depending on how you count:
+ *     Desired block is in the cache:
+ *         1 Not sequential access (0 I/Os).
+ *         2 Access is sequential, do read-ahead (1 ASYNC).
+ *     Desired block is not in cache:
+ *         3 Not sequential access (1 SYNC).
+ *         4 Sequential access, next block is contiguous (1 SYNC).
+ *         5 Sequential access, next block is not contiguous (1 SYNC, 1 ASYNC)
+ *
+ * There are potentially two buffers that require I/O.
+ *     bp is the block requested.
+ *     rbp is the read-ahead block.
+ *     If either is NULL, then you don't have to do the I/O.

  */
  */

-breada(vp, blkno, size, rablkno, rabsize, bpp)
+cluster_read(vp, filesize, lblkno, size, cred, bpp)

        struct vnode *vp;
        struct vnode *vp;

-       daddr_t blkno; int size;
-#ifdef SECSIZE
-       long secsize;
-#endif SECSIZE
-       daddr_t rablkno; int rabsize;
+       u_quad_t filesize;
+       daddr_t lblkno;
+       long size;
+       struct ucred *cred;

        struct buf **bpp;
 {
        struct buf **bpp;
 {

-       register struct buf *bp, *rabp;
+       struct buf *bp, *rbp;
+       daddr_t blkno, ioblkno;
+       long flags;
+       int error, num_ra, alreadyincore;

 
 

-       bp = NULL;
-       /*
-        * 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;
-                       if (bp->b_bcount > bp->b_bufsize)
-                               panic("breada");
-                       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);
-       }
+#ifdef DIAGNOSTIC
+       if (size == 0)
+               panic("cluster_read: size = 0");
+#endif

 
 

+       error = 0;
+       flags = B_READ;
+       *bpp = bp = getblk(vp, lblkno, size, 0, 0);
+       if (bp->b_flags & B_CACHE) {
+               /*
+                * Desired block is in cache; do any readahead ASYNC.
+                * Case 1, 2.
+                */
+               trace(TR_BREADHIT, pack(vp, size), lblkno);
+               flags |= B_ASYNC;
+               ioblkno = lblkno + (vp->v_ralen ? vp->v_ralen : 1);
+               alreadyincore = incore(vp, ioblkno) != NULL;
+               bp = NULL;
+       } else {
+               /* Block wasn't in cache, case 3, 4, 5. */
+               trace(TR_BREADMISS, pack(vp, size), lblkno);
+               bp->b_flags |= B_READ;
+               ioblkno = lblkno;
+               alreadyincore = 0;
+               curproc->p_stats->p_ru.ru_inblock++;            /* XXX */
+       }

        /*
        /*

-        * If there's a read-ahead block, start i/o
-        * on it also (as above).
+        * XXX
+        * Replace 1 with a window size based on some permutation of
+        * maxcontig and rot_delay.  This will let you figure out how
+        * many blocks you should read-ahead (case 2, 4, 5).
+        *
+        * If the access isn't sequential, reset the window to 1.
+        * Note that a read to the same block is considered sequential.
+        * This catches the case where the file is being read sequentially,
+        * but at smaller than the filesystem block size.

         */
         */

-       if (rablkno && !incore(vp, rablkno)) {
-               rabp = getblk(vp, rablkno, rabsize);
-#endif SECSIZE
-               if (rabp->b_flags & (B_DONE|B_DELWRI)) {
-                       brelse(rabp);
-                       trace(TR_BREADHITRA,
-                           pack(vp->v_mount->m_fsid[0], rabsize), blkno);
+       rbp = NULL;
+       if (!ISSEQREAD(vp, lblkno)) {
+               vp->v_ralen = 0;
+               vp->v_maxra = lblkno;
+       } else if ((ioblkno + 1) * size <= filesize && !alreadyincore &&
+           !(error = VOP_BMAP(vp, ioblkno, NULL, &blkno, &num_ra)) &&
+           blkno != -1) {
+               /*
+                * Reading sequentially, and the next block is not in the
+                * cache.  We are going to try reading ahead.
+                */
+               if (num_ra) {
+                       /*
+                        * If our desired readahead block had been read
+                        * in a previous readahead but is no longer in
+                        * core, then we may be reading ahead too far
+                        * or are not using our readahead very rapidly.
+                        * In this case we scale back the window.
+                        */
+                       if (!alreadyincore && ioblkno <= vp->v_maxra)
+                               vp->v_ralen = max(vp->v_ralen >> 1, 1);
+                       /*
+                        * There are more sequential blocks than our current
+                        * window allows, scale up.  Ideally we want to get
+                        * in sync with the filesystem maxcontig value.
+                        */
+                       else if (num_ra > vp->v_ralen && lblkno != vp->v_lastr)
+                               vp->v_ralen = vp->v_ralen ?
+                                       min(num_ra, vp->v_ralen << 1) : 1;
+
+                       if (num_ra > vp->v_ralen)
+                               num_ra = vp->v_ralen;
+               }
+
+               if (num_ra)                             /* case 2, 4 */
+                       rbp = cluster_rbuild(vp, filesize,
+                           bp, ioblkno, blkno, size, num_ra, flags);
+               else if (ioblkno == lblkno) {
+                       bp->b_blkno = blkno;
+                       /* Case 5: check how many blocks to read ahead */
+                       ++ioblkno;
+                       if ((ioblkno + 1) * size > filesize ||
+                           incore(vp, ioblkno) || (error = VOP_BMAP(vp,
+                            ioblkno, NULL, &blkno, &num_ra)) || blkno == -1)
+                               goto skip_readahead;
+                       /*
+                        * Adjust readahead as above.
+                        * Don't check alreadyincore, we know it is 0 from
+                        * the previous conditional.
+                        */
+                       if (num_ra) {
+                               if (ioblkno <= vp->v_maxra)
+                                       vp->v_ralen = max(vp->v_ralen >> 1, 1);
+                               else if (num_ra > vp->v_ralen &&
+                                        lblkno != vp->v_lastr)
+                                       vp->v_ralen = vp->v_ralen ?
+                                               min(num_ra,vp->v_ralen<<1) : 1;
+                               if (num_ra > vp->v_ralen)
+                                       num_ra = vp->v_ralen;
+                       }
+                       flags |= B_ASYNC;
+                       if (num_ra)
+                               rbp = cluster_rbuild(vp, filesize,
+                                   NULL, ioblkno, blkno, size, num_ra, flags);
+                       else {
+                               rbp = getblk(vp, ioblkno, size, 0, 0);
+                               rbp->b_flags |= flags;
+                               rbp->b_blkno = blkno;
+                       }

                } else {
                } else {

-                       rabp->b_flags |= B_READ|B_ASYNC;
-                       if (rabp->b_bcount > rabp->b_bufsize)
-                               panic("breadrabp");
-                       VOP_STRATEGY(rabp);
+                       /* case 2; read ahead single block */
+                       rbp = getblk(vp, ioblkno, size, 0, 0);
+                       rbp->b_flags |= flags;
+                       rbp->b_blkno = blkno;
+               }
+
+               if (rbp == bp)                  /* case 4 */
+                       rbp = NULL;
+               else if (rbp) {                 /* case 2, 5 */

                        trace(TR_BREADMISSRA,
                        trace(TR_BREADMISSRA,

-                           pack(vp->v_mount->m_fsid[0], rabsize), rablock);
-                       u.u_ru.ru_inblock++;            /* pay in advance */
+                           pack(vp, (num_ra + 1) * size), ioblkno);
+                       curproc->p_stats->p_ru.ru_inblock++;    /* XXX */

                }
        }
 
                }
        }
 

+       /* XXX Kirk, do we need to make sure the bp has creds? */
+skip_readahead:
+       if (bp)
+               if (bp->b_flags & (B_DONE | B_DELWRI))
+                       panic("cluster_read: DONE bp");
+               else 
+                       error = VOP_STRATEGY(bp);
+
+       if (rbp)
+               if (error || rbp->b_flags & (B_DONE | B_DELWRI)) {
+                       rbp->b_flags &= ~(B_ASYNC | B_READ);
+                       brelse(rbp);
+               } else
+                       (void) VOP_STRATEGY(rbp);
+

        /*
        /*

-        * 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.
+        * Recalculate our maximum readahead

         */
         */

-       if (bp == NULL)
-#ifdef SECSIZE
-               return (bread(dev, blkno, size, secsize));
-#else SECSIZE
-               return (bread(vp, blkno, size, bpp));
-       return (biowait(bp));
+       if (rbp == NULL)
+               rbp = bp;
+       if (rbp)
+               vp->v_maxra = rbp->b_lblkno + (rbp->b_bufsize / size) - 1;
+
+       if (bp)
+               return(biowait(bp));
+       return(error);

 }
 
 /*
 }
 
 /*

- * Write the buffer, waiting for completion.
- * Then release the buffer.
+ * If blocks are contiguous on disk, use this to provide clustered
+ * read ahead.  We will read as many blocks as possible sequentially
+ * and then parcel them up into logical blocks in the buffer hash table.

  */
  */

-bwrite(bp)
-       register struct buf *bp;
+struct buf *
+cluster_rbuild(vp, filesize, bp, lbn, blkno, size, run, flags)
+       struct vnode *vp;
+       u_quad_t filesize;
+       struct buf *bp;
+       daddr_t lbn;
+       daddr_t blkno;
+       long size;
+       int run;
+       long flags;

 {
 {

-       register int flag;
-       int error;
-
-       flag = bp->b_flags;
-       bp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI);
-       if ((flag&B_DELWRI) == 0)
-               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_blkno);
-       if (bp->b_bcount > bp->b_bufsize)
-               panic("bwrite");
-       VOP_STRATEGY(bp);
+       struct cluster_save *b_save;
+       struct buf *tbp;
+       daddr_t bn;
+       int i, inc;
+
+#ifdef DIAGNOSTIC
+       if (size != vp->v_mount->mnt_stat.f_iosize)
+               panic("cluster_rbuild: size %d != filesize %d\n",
+                       size, vp->v_mount->mnt_stat.f_iosize);
+#endif
+       if (size * (lbn + run + 1) > filesize)
+               --run;
+       if (run == 0) {
+               if (!bp) {
+                       bp = getblk(vp, lbn, size, 0, 0);
+                       bp->b_blkno = blkno;
+                       bp->b_flags |= flags;
+               }
+               return(bp);
+       }
+
+       bp = cluster_newbuf(vp, bp, flags, blkno, lbn, size, run + 1);
+       if (bp->b_flags & (B_DONE | B_DELWRI))
+               return (bp);

 
 

+       b_save = malloc(sizeof(struct buf *) * run + sizeof(struct cluster_save),
+           M_SEGMENT, M_WAITOK);
+       b_save->bs_bufsize = b_save->bs_bcount = size;
+       b_save->bs_nchildren = 0;
+       b_save->bs_children = (struct buf **)(b_save + 1);
+       b_save->bs_saveaddr = bp->b_saveaddr;
+       bp->b_saveaddr = (caddr_t) b_save;
+
+       inc = btodb(size);
+       for (bn = blkno + inc, i = 1; i <= run; ++i, bn += inc) {
+               /*
+                * A component of the cluster is already in core,
+                * terminate the cluster early.
+                */
+               if (incore(vp, lbn + i))
+                       break;
+               tbp = getblk(vp, lbn + i, 0, 0, 0);
+               /*
+                * getblk may return some memory in the buffer if there were
+                * no empty buffers to shed it to.  If there is currently
+                * memory in the buffer, we move it down size bytes to make
+                * room for the valid pages that cluster_callback will insert.
+                * We do this now so we don't have to do it at interrupt time
+                * in the callback routine.
+                */
+               if (tbp->b_bufsize != 0) {
+                       caddr_t bdata = (char *)tbp->b_data;
+
+                       /*
+                        * No room in the buffer to add another page,
+                        * terminate the cluster early.
+                        */
+                       if (tbp->b_bufsize + size > MAXBSIZE) {
+#ifdef DIAGNOSTIC
+                               if (tbp->b_bufsize != MAXBSIZE)
+                                       panic("cluster_rbuild: too much memory");
+#endif
+                               brelse(tbp);
+                               break;
+                       }
+                       if (tbp->b_bufsize > size) {
+                               /*
+                                * XXX if the source and destination regions
+                                * overlap we have to copy backward to avoid
+                                * clobbering any valid pages (i.e. pagemove
+                                * implementations typically can't handle
+                                * overlap).
+                                */
+                               bdata += tbp->b_bufsize;
+                               while (bdata > (char *)tbp->b_data) {
+                                       bdata -= CLBYTES;
+                                       pagemove(bdata, bdata + size, CLBYTES);
+                               }
+                       } else 
+                               pagemove(bdata, bdata + size, tbp->b_bufsize);
+               }
+               tbp->b_blkno = bn;
+               {
+                       daddr_t temp;
+                       VOP_BMAP(tbp->b_vp, tbp->b_lblkno, NULL, &temp, NULL);
+                       if (temp != bn) {
+                               printf("Block: %d Assigned address: %x Bmap address: %x\n",
+                                           tbp->b_lblkno, tbp->b_blkno, temp);
+                               panic("cluster_rbuild: wrong disk address");
+                       }
+               }
+               tbp->b_flags |= flags | B_READ | B_ASYNC;
+               ++b_save->bs_nchildren;
+               b_save->bs_children[i - 1] = tbp;
+       }

        /*
        /*

-        * 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.
+        * The cluster may have been terminated early, adjust the cluster
+        * buffer size accordingly.  If no cluster could be formed,
+        * deallocate the cluster save info.

         */
         */

-       if ((flag&B_ASYNC) == 0) {
-               error = biowait(bp);
-               brelse(bp);
-       } else if (flag & B_DELWRI) {
-               bp->b_flags |= B_AGE;
-               error = 0;
+       if (i <= run) {
+               if (i == 1) {
+                       bp->b_saveaddr = b_save->bs_saveaddr;
+                       bp->b_flags &= ~B_CALL;
+                       bp->b_iodone = NULL;
+                       free(b_save, M_SEGMENT);
+               }
+               allocbuf(bp, size * i);

        }
        }

-       return (error);
+       return(bp);

 }
 
 /*
 }
 
 /*

- * Release the buffer, marking it so that if it is grabbed
- * for another purpose it will be written out before being
- * given up (e.g. when writing a partial block where it is
- * assumed that another write for the same block will soon follow).
- * This can't be done for magtape, since writes must be done
- * in the same order as requested.
+ * Either get a new buffer or grow the existing one.

  */
  */

-bdwrite(bp)
-       register struct buf *bp;
+struct buf *
+cluster_newbuf(vp, bp, flags, blkno, lblkno, size, run)
+       struct vnode *vp;
+       struct buf *bp;
+       long flags;
+       daddr_t blkno;
+       daddr_t lblkno;
+       long size;
+       int run;

 {
 {

-
-       if ((bp->b_flags&B_DELWRI) == 0)
-               u.u_ru.ru_oublock++;            /* noone paid yet */
-#ifdef notdef
-       /*
-        * This does not work for buffers associated with
-        * vnodes that are remote - they have no dev.
-        * Besides, we don't use bio with tapes, so rather
-        * than develop a fix, we just ifdef this out for now.
-        */
-       if (bdevsw[major(bp->b_dev)].d_flags & B_TAPE)
-               bawrite(bp);
-       else {
-               bp->b_flags |= B_DELWRI | B_DONE;
-               brelse(bp);
+       if (!bp) {
+               bp = getblk(vp, lblkno, size, 0, 0);
+               if (bp->b_flags & (B_DONE | B_DELWRI)) {
+                       bp->b_blkno = blkno;
+                       return(bp);
+               }

        }
        }

-#endif
-       bp->b_flags |= B_DELWRI | B_DONE;
-       brelse(bp);
+       allocbuf(bp, run * size);
+       bp->b_blkno = blkno;
+       bp->b_iodone = cluster_callback;
+       bp->b_flags |= flags | B_CALL;
+       return(bp);

 }
 
 /*
 }
 
 /*

- * Release the buffer, start I/O on it, but don't wait for completion.
+ * Cleanup after a clustered read or write.
+ * This is complicated by the fact that any of the buffers might have
+ * extra memory (if there were no empty buffer headers at allocbuf time)
+ * that we will need to shift around.

  */
  */

-bawrite(bp)
-       register struct buf *bp;
+void
+cluster_callback(bp)
+       struct buf *bp;

 {
 {

+       struct cluster_save *b_save;
+       struct buf **bpp, *tbp;
+       long bsize;
+       caddr_t cp;
+       int error = 0;

 
 

-       bp->b_flags |= B_ASYNC;
-       (void) bwrite(bp);
-}
+       /*
+        * Must propogate errors to all the components.
+        */
+       if (bp->b_flags & B_ERROR)
+               error = bp->b_error;

 
 

-/*
- * Release the buffer, with no I/O implied.
- */
-brelse(bp)
-       register struct buf *bp;
-{
-       register struct buf *flist;
-       register s;
+       daddr_t daddr;
+       b_save = (struct cluster_save *)(bp->b_saveaddr);
+       bp->b_saveaddr = b_save->bs_saveaddr;

 
 

-       trace(TR_BRELSE,
-           pack(bp->b_vp->v_mount->m_fsid[0], bp->b_bufsize), bp->b_blkno);
+       bsize = b_save->bs_bufsize;
+       cp = (char *)bp->b_data + bsize;

        /*
        /*

-        * If someone's waiting for the buffer, or
-        * is waiting for a buffer wake 'em up.
+        * Move memory from the large cluster buffer into the component
+        * buffers and mark IO as done on these.

         */
         */

-       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);
-       }
-       if (bp->b_flags & B_NOCACHE) {
-               bp->b_flags |= B_INVAL;
+       for (bpp = b_save->bs_children; b_save->bs_nchildren--; ++bpp) {
+               tbp = *bpp;
+               pagemove(cp, tbp->b_data, bsize);
+               tbp->b_bufsize += bsize;
+               tbp->b_bcount = bsize;
+               if (error) {
+                       tbp->b_flags |= B_ERROR;
+                       tbp->b_error = error;
+               }
+               biodone(tbp);
+               bp->b_bufsize -= bsize;
+               cp += bsize;

        }
        }

-       if (bp->b_flags&B_ERROR)
-               if (bp->b_flags & B_LOCKED)
-                       bp->b_flags &= ~B_ERROR;        /* try again later */
-               else
-                       brelvp(bp);                     /* no assoc */
-

        /*
        /*

-        * Stick the buffer back on a free list.
+        * If there was excess memory in the cluster buffer,
+        * slide it up adjacent to the remaining valid data.

         */
         */

-       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 {
-               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);
+       if (bp->b_bufsize != bsize) {
+               if (bp->b_bufsize < bsize)
+                       panic("cluster_callback: too little memory");
+               pagemove(cp, (char *)bp->b_data + bsize, bp->b_bufsize - bsize);
+       }
+       bp->b_bcount = bsize;
+       bp->b_iodone = NULL;
+       free(b_save, M_SEGMENT);
+       if (bp->b_flags & B_ASYNC)
+               brelse(bp);
+       else {
+               bp->b_flags &= ~B_WANTED;
+               wakeup((caddr_t)bp);

        }
        }

-       bp->b_flags &= ~(B_WANTED|B_BUSY|B_ASYNC|B_AGE|B_NOCACHE);
-       splx(s);
-}
-
-/*
- * See if the block is associated with some buffer
- * (mainly to avoid getting hung up on a wait in breada)
- */
-incore(vp, blkno)
-       struct vnode *vp;
-       daddr_t blkno;
-{
-       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_blkno == blkno && bp->b_vp == vp &&
-                   (bp->b_flags & B_INVAL) == 0)
-                       return (1);
-       return (0);
-}
-
-baddr(vp, blkno, size, bpp)
-       struct vnode *vp;
-       daddr_t blkno;
-       int size;
-       struct buf **bpp;
-#ifdef SECSIZE
-       long secsize;
-#endif SECSIZE
-{
-
-       if (incore(vp, blkno))
-               return (bread(vp, blkno, size, bpp));
-       *bpp = 0;
-#endif SECSIZE
-       return (0);

 }
 
 /*
 }
 
 /*

- * 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.
- *
- * If we find the buffer, but it is dirty (marked DELWRI) and
- * its size is changing, we must write it out first. When the
- * buffer is shrinking, the write is done by brealloc to avoid
- * losing the unwritten data. When the buffer is growing, the
- * write is done by getblk, so that bread will not read stale
- * disk data over the modified data in the buffer.
+ * Do clustered write for FFS.

  *
  *

- * 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.
+ * Three cases:
+ *     1. Write is not sequential (write asynchronously)
+ *     Write is sequential:
+ *     2.      beginning of cluster - begin cluster
+ *     3.      middle of a cluster - add to cluster
+ *     4.      end of a cluster - asynchronously write cluster

  */
  */

-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
+void
+cluster_write(bp, filesize)
+        struct buf *bp;
+       u_quad_t filesize;

 {
 {

-       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
-        */
-       if ((unsigned)blkno >= 1 << (sizeof(int)*NBBY-DEV_BSHIFT))
-               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_blkno != 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;
-               }
-               splx(s);
-               notavail(bp);
-               if (bp->b_bcount != size) {
-                       if (bp->b_bcount < size && (bp->b_flags&B_DELWRI)) {
-                               bp->b_flags &= ~B_ASYNC;
-                               (void) bwrite(bp);
-                               goto loop;
+        struct vnode *vp;
+        daddr_t lbn;
+        int maxclen, cursize;
+
+        vp = bp->b_vp;
+        lbn = bp->b_lblkno;
+
+       /* Initialize vnode to beginning of file. */
+       if (lbn == 0)
+               vp->v_lasta = vp->v_clen = vp->v_cstart = vp->v_lastw = 0;
+
+        if (vp->v_clen == 0 || lbn != vp->v_lastw + 1 ||
+           (bp->b_blkno != vp->v_lasta + btodb(bp->b_bcount))) {
+               maxclen = MAXBSIZE / vp->v_mount->mnt_stat.f_iosize - 1;
+               if (vp->v_clen != 0) {
+                       /*
+                        * Next block is not sequential.
+                        *
+                        * If we are not writing at end of file, the process
+                        * seeked to another point in the file since its
+                        * last write, or we have reached our maximum
+                        * cluster size, then push the previous cluster.
+                        * Otherwise try reallocating to make it sequential.
+                        */
+                       cursize = vp->v_lastw - vp->v_cstart + 1;
+                       if ((lbn + 1) * bp->b_bcount != filesize ||
+                           lbn != vp->v_lastw + 1 || vp->v_clen <= cursize) {
+                               cluster_wbuild(vp, NULL, bp->b_bcount,
+                                   vp->v_cstart, cursize, lbn);
+                       } else {
+                               struct buf **bpp, **endbp;
+                               struct cluster_save *buflist;
+
+                               buflist = cluster_collectbufs(vp, bp);
+                               endbp = &buflist->bs_children
+                                   [buflist->bs_nchildren - 1];
+                               if (VOP_REALLOCBLKS(vp, buflist)) {
+                                       /*
+                                        * Failed, push the previous cluster.
+                                        */
+                                       for (bpp = buflist->bs_children;
+                                            bpp < endbp; bpp++)
+                                               brelse(*bpp);
+                                       free(buflist, M_SEGMENT);
+                                       cluster_wbuild(vp, NULL, bp->b_bcount,
+                                           vp->v_cstart, cursize, lbn);
+                               } else {
+                                       /*
+                                        * Succeeded, keep building cluster.
+                                        */
+                                       for (bpp = buflist->bs_children;
+                                            bpp <= endbp; bpp++)
+                                               bdwrite(*bpp);
+                                       free(buflist, M_SEGMENT);
+                                       vp->v_lastw = lbn;
+                                       vp->v_lasta = bp->b_blkno;
+                                       return;
+                               }

                        }
                        }

-                       if (brealloc(bp, size) == 0)
-                               goto loop;

                }
                }

-               if (bp->b_bcount != size && brealloc(bp, size) == 0)
-                       goto loop;
-               bp->b_flags |= B_CACHE;
-               return (bp);
-       }
-       bp = getnewbuf();
-       bfree(bp);
-       bremhash(bp);
-       if (bp->b_vp)
-               brelvp(bp);
-       VREF(vp);
-       bp->b_vp = vp;
-       bp->b_dev = vp->v_rdev;
-#ifdef SECSIZE
-       bp->b_blksize = secsize;
-#endif SECSIZE
-       bp->b_blkno = blkno;
-       bp->b_error = 0;
-       bp->b_resid = 0;
-       binshash(bp, dp);
-       if (brealloc(bp, size) == 0)
-               goto loop;
-       return (bp);
+               /*
+                * Consider beginning a cluster.
+                * If at end of file, make cluster as large as possible,
+                * otherwise find size of existing cluster.
+                */
+               if ((lbn + 1) * bp->b_bcount != filesize &&
+                   (VOP_BMAP(vp, lbn, NULL, &bp->b_blkno, &maxclen) ||
+                    bp->b_blkno == -1)) {
+                       bawrite(bp);
+                       vp->v_clen = 0;
+                       vp->v_lasta = bp->b_blkno;
+                       vp->v_cstart = lbn + 1;
+                       vp->v_lastw = lbn;
+                       return;
+               }
+                vp->v_clen = maxclen;
+                if (maxclen == 0) {            /* I/O not contiguous */
+                       vp->v_cstart = lbn + 1;
+                        bawrite(bp);
+                } else {                       /* Wait for rest of cluster */
+                       vp->v_cstart = lbn;
+                        bdwrite(bp);
+               }
+       } else if (lbn == vp->v_cstart + vp->v_clen) {
+               /*
+                * At end of cluster, write it out.
+                */
+               cluster_wbuild(vp, bp, bp->b_bcount, vp->v_cstart,
+                   vp->v_clen + 1, lbn);
+               vp->v_clen = 0;
+               vp->v_cstart = lbn + 1;
+       } else
+               /*
+                * In the middle of a cluster, so just delay the
+                * I/O for now.
+                */
+               bdwrite(bp);
+       vp->v_lastw = lbn;
+       vp->v_lasta = bp->b_blkno;

 }
 
 }
 

-/*
- * get an empty block,
- * not assigned to any particular device
- */
-struct buf *
-geteblk(size)
-       int size;
-{
-       register struct buf *bp, *flist;
-
-       if (size > MAXBSIZE)
-               panic("geteblk: size too big");
-loop:
-       bp = getnewbuf();
-       bp->b_flags |= B_INVAL;
-       bfree(bp);
-       bremhash(bp);
-       flist = &bfreelist[BQ_AGE];
-       brelvp(bp);
-#ifdef SECSIZE
-       bp->b_blksize = DEV_BSIZE;
-#endif SECSIZE
-       bp->b_error = 0;
-       bp->b_resid = 0;
-       binshash(bp, flist);
-       if (brealloc(bp, size) == 0)
-               goto loop;
-       return (bp);
-}

 
 /*
 
 /*

- * Allocate space associated with a buffer.
- * If can't get space, buffer is released
+ * This is an awful lot like cluster_rbuild...wish they could be combined.
+ * The last lbn argument is the current block on which I/O is being
+ * performed.  Check to see that it doesn't fall in the middle of
+ * the current block (if last_bp == NULL).

  */
  */

-brealloc(bp, size)
-       register struct buf *bp;
-       int size;
+void
+cluster_wbuild(vp, last_bp, size, start_lbn, len, lbn)
+       struct vnode *vp;
+       struct buf *last_bp;
+       long size;
+       daddr_t start_lbn;
+       int len;
+       daddr_t lbn;

 {
 {

-       daddr_t start, last;
-       register struct buf *ep;
-       struct buf *dp;
-       int s;
+       struct cluster_save *b_save;
+       struct buf *bp, *tbp;
+       caddr_t cp;
+       int i, s;
+
+#ifdef DIAGNOSTIC
+       if (size != vp->v_mount->mnt_stat.f_iosize)
+               panic("cluster_wbuild: size %d != filesize %d\n",
+                       size, vp->v_mount->mnt_stat.f_iosize);
+#endif
+redo:
+       while ((!incore(vp, start_lbn) || start_lbn == lbn) && len) {
+               ++start_lbn;
+               --len;
+       }

 
 

-       /*
-        * First need to make sure that all overlapping previous I/O
-        * is dispatched with.
-        */
-       if (size == bp->b_bcount)
-               return (1);
-       if (size < bp->b_bcount) { 
-               if (bp->b_flags & B_DELWRI) {
-                       (void) bwrite(bp);
-                       return (0);
+       /* Get more memory for current buffer */
+       if (len <= 1) {
+               if (last_bp) {
+                       bawrite(last_bp);
+               } else if (len) {
+                       bp = getblk(vp, start_lbn, size, 0, 0);
+                       bawrite(bp);

                }
                }

-               if (bp->b_flags & B_LOCKED)
-                       panic("brealloc");
-               return (allocbuf(bp, size));
+               return;
+       }
+
+       bp = getblk(vp, start_lbn, size, 0, 0);
+       if (!(bp->b_flags & B_DELWRI)) {
+               ++start_lbn;
+               --len;
+               brelse(bp);
+               goto redo;

        }
        }

-       bp->b_flags &= ~B_DONE;
-       if (bp->b_vp == (struct vnode *)0)
-               return (allocbuf(bp, size));

 
 

-       trace(TR_BREALLOC,
-           pack(bp->b_vp->v_mount->m_fsid[0], size), bp->b_blkno);

        /*
        /*

-        * Search cache for any buffers that overlap the one that we
-        * are trying to allocate. Overlapping buffers must be marked
-        * invalid, after being written out if they are dirty. (indicated
-        * by B_DELWRI) A disk block must be mapped by at most one buffer
-        * at any point in time. Care must be taken to avoid deadlocking
-        * when two buffer are trying to get the same set of disk blocks.
+        * Extra memory in the buffer, punt on this buffer.
+        * XXX we could handle this in most cases, but we would have to
+        * push the extra memory down to after our max possible cluster
+        * size and then potentially pull it back up if the cluster was
+        * terminated prematurely--too much hassle.

         */
         */

-       start = bp->b_blkno;
-#ifdef SECSIZE
-       last = start + size/bp->b_blksize - 1;
-#else SECSIZE
-       last = start + btodb(size) - 1;
-#endif SECSIZE
-       dp = BUFHASH(bp->b_vp, bp->b_blkno);
-loop:
-       for (ep = dp->b_forw; ep != dp; ep = ep->b_forw) {
-               if (ep == bp || ep->b_vp != bp->b_vp ||
-                   (ep->b_flags & B_INVAL))
-                       continue;
-               /* look for overlap */
-               if (ep->b_bcount == 0 || ep->b_blkno > last ||
-#ifdef SECSIZE
-                   ep->b_blkno + ep->b_bcount/ep->b_blksize <= start)
-#else SECSIZE
-                   ep->b_blkno + btodb(ep->b_bcount) <= start)
-#endif SECSIZE
-                       continue;
-               s = splbio();
-               if (ep->b_flags&B_BUSY) {
-                       ep->b_flags |= B_WANTED;
-                       sleep((caddr_t)ep, PRIBIO+1);
-                       splx(s);
-                       goto loop;
-               }
-               splx(s);
-               notavail(ep);
-               if (ep->b_flags & B_DELWRI) {
-                       (void) bwrite(ep);
-                       goto loop;
-               }
-               ep->b_flags |= B_INVAL;
-               brelse(ep);
+       if (bp->b_bcount != bp->b_bufsize) {
+               ++start_lbn;
+               --len;
+               bawrite(bp);
+               goto redo;

        }
        }

-       return (allocbuf(bp, size));
-}

 
 

-/*
- * 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()
-{
-       register struct buf *bp, *dp;
-       int s;
-
-loop:
-       s = splbio();
-       for (dp = &bfreelist[BQ_AGE]; dp > bfreelist; dp--)
-               if (dp->av_forw != dp)
+       --len;
+       b_save = malloc(sizeof(struct buf *) * len + sizeof(struct cluster_save),
+           M_SEGMENT, M_WAITOK);
+       b_save->bs_bcount = bp->b_bcount;
+       b_save->bs_bufsize = bp->b_bufsize;
+       b_save->bs_nchildren = 0;
+       b_save->bs_children = (struct buf **)(b_save + 1);
+       b_save->bs_saveaddr = bp->b_saveaddr;
+       bp->b_saveaddr = (caddr_t) b_save;
+
+       bp->b_flags |= B_CALL;
+       bp->b_iodone = cluster_callback;
+       cp = (char *)bp->b_data + size;
+       for (++start_lbn, i = 0; i < len; ++i, ++start_lbn) {
+               /*
+                * Block is not in core or the non-sequential block
+                * ending our cluster was part of the cluster (in which
+                * case we don't want to write it twice).
+                */
+               if (!incore(vp, start_lbn) ||
+                   last_bp == NULL && start_lbn == lbn)

                        break;
                        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_blkno);
-       brelvp(bp);
-       bp->b_flags = B_BUSY;
-       return (bp);
-}

 
 

-/*
- * Wait for I/O completion on the buffer; return errors
- * to the user.
- */
-biowait(bp)
-       register struct buf *bp;
-{
-       int s;
+               /*
+                * Get the desired block buffer (unless it is the final
+                * sequential block whose buffer was passed in explictly
+                * as last_bp).
+                */
+               if (last_bp == NULL || start_lbn != lbn) {
+                       tbp = getblk(vp, start_lbn, size, 0, 0);
+                       if (!(tbp->b_flags & B_DELWRI)) {
+                               brelse(tbp);
+                               break;
+                       }
+               } else
+                       tbp = last_bp;

 
 

-       s = splbio();
-       while ((bp->b_flags&B_DONE)==0)
-               sleep((caddr_t)bp, PRIBIO);
-       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);
-}
+               ++b_save->bs_nchildren;

 
 

-/*
- * 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.
- */
-biodone(bp)
-       register struct buf *bp;
-{
+               /* Move memory from children to parent */
+               if (tbp->b_blkno != (bp->b_blkno + btodb(bp->b_bufsize))) {
+                       printf("Clustered Block: %d addr %x bufsize: %d\n",
+                           bp->b_lblkno, bp->b_blkno, bp->b_bufsize);
+                       printf("Child Block: %d addr: %x\n", tbp->b_lblkno,
+                           tbp->b_blkno);
+                       panic("Clustered write to wrong blocks");
+               }

 
 

-       if (bp->b_flags & B_DONE)
-               panic("dup biodone");
-       bp->b_flags |= B_DONE;
-       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);
-       }
-}
+               pagemove(tbp->b_data, cp, size);
+               bp->b_bcount += size;
+               bp->b_bufsize += size;

 
 

-/*
- * 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_blkno).
-#endif SECSIZE
-#ifdef SECSIZE
- * "size" is given in device blocks (the units of b_blkno).
-#endif SECSIZE
- */
-blkflush(vp, blkno, size)
-       struct vnode *vp;
-       daddr_t blkno;
-#ifdef SECSIZE
-       int size;
-#else SECSIZE
-       long size;
-#endif SECSIZE
-{
-       register struct buf *ep;
-       struct buf *dp;
-       daddr_t start, last;
-       int s, error, allerrors = 0;
-
-       start = blkno;
-#ifdef SECSIZE
-       last = start + size - 1;
-#else SECSIZE
-       last = start + btodb(size) - 1;
-#endif SECSIZE
-       dp = BUFHASH(vp, blkno);
-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_blkno > last ||
-#ifdef SECSIZE
-                   ep->b_blkno + ep->b_bcount / ep->b_blksize <= start)
-#else SECSIZE
-                   ep->b_blkno + btodb(ep->b_bcount) <= start)
-#endif SECSIZE
-                       continue;
+               tbp->b_bufsize -= size;
+               tbp->b_flags &= ~(B_READ | B_DONE | B_ERROR | B_DELWRI);
+               tbp->b_flags |= (B_ASYNC | B_AGE);

                s = splbio();
                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;
-               }
+               reassignbuf(tbp, tbp->b_vp);            /* put on clean list */
+               ++tbp->b_vp->v_numoutput;

                splx(s);
                splx(s);

-       }
-       return (allerrors);
-}
+               b_save->bs_children[i] = tbp;

 
 

-/*
- * Make sure all write-behind blocks associated
- * with vp are flushed out (from sync).
- */
-bflush(dev)
-       dev_t dev;
-{
-       register struct buf *bp;
-       register struct buf *flist;
-       int s;
-
-loop:
-       s = splbio();
-       for (flist = bfreelist; flist < &bfreelist[BQ_EMPTY]; flist++)
-       for (bp = flist->av_forw; bp != flist; bp = bp->av_forw) {
-               if ((bp->b_flags & B_DELWRI) == 0)
-                       continue;
-               if (dev == NODEV || dev == bp->b_dev) {
-                       notavail(bp);
-                       (void) bawrite(bp);
-                       splx(s);
-                       goto loop;
-               }
+               cp += size;

        }
        }

-       splx(s);
-}

 
 

-#ifdef unused
-/*
- * Invalidate blocks associated with vp which are on the freelist.
- * Make sure all write-behind blocks associated with vp are flushed out.
- */
-binvalfree(vp)
-       struct vnode *vp;
-{
-       register struct buf *bp;
-       register struct buf *flist;
-       int s;
-
-loop:
-       s = splbio();
-       for (flist = bfreelist; flist < &bfreelist[BQ_EMPTY]; flist++)
-       for (bp = flist->av_forw; bp != flist; bp = bp->av_forw) {
-               if (vp == (struct vnode *) 0 || vp == bp->b_vp) {
-                       if (bp->b_flags & B_DELWRI) {
-                               notavail(bp);
-                               (void) splx(s);
-                               (void) bawrite(bp);
-                       } else {
-                               bp->b_flags |= B_INVAL;
-                               brelvp(bp);
-                               (void) splx(s);
-                       }
-                       goto loop;
-               }
+       if (i == 0) {
+               /* None to cluster */
+               bp->b_saveaddr = b_save->bs_saveaddr;
+               bp->b_flags &= ~B_CALL;
+               bp->b_iodone = NULL;
+               free(b_save, M_SEGMENT);
+       }
+       bawrite(bp);
+       if (i < len) {
+               len -= i + 1;
+               start_lbn += 1;
+               goto redo;

        }
        }

-       (void) splx(s);

 }
 }

-#endif /* unused */

 
 /*
 
 /*

- * Invalidate in core blocks belonging to closed or umounted filesystem
- *
- * We walk through the buffer pool and invalidate any buffers for the
- * indicated device. 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. We return the count of dirty buffers when
- * we are finished.
+ * Collect together all the buffers in a cluster.
+ * Plus add one additional buffer.

  */
  */

-binval(dev)
-       dev_t dev;
-{
-       register struct buf *bp;
-       register struct bufhd *hp;
-       int dirty = 0;
-#define dp ((struct buf *)hp)
-
-       for (hp = bufhash; hp < &bufhash[BUFHSZ]; hp++) {
-               for (bp = dp->b_forw; bp != dp; bp = bp->b_forw) {
-                       if (bp->b_dev != dev || (bp->b_flags & B_INVAL))
-                               continue;
-                       notavail(bp);
-                       if (bp->b_flags & B_DELWRI) {
-                               (void) bawrite(bp);
-                               dirty++;
-                               continue;
-                       }
-                       bp->b_flags |= B_INVAL;
-                       brelvp(bp);
-                       brelse(bp);
-               }
-       }
-       return (dirty);
-}
-
-brelvp(bp)
-       struct buf *bp;
-{
+struct cluster_save *
+cluster_collectbufs(vp, last_bp)

        struct vnode *vp;
        struct vnode *vp;

-
-       if (bp->b_vp == (struct vnode *) 0)
-               return;
-       vp = bp->b_vp;
-       bp->b_vp = (struct vnode *) 0;
-       vrele(vp);
+       struct buf *last_bp;
+{
+       struct cluster_save *buflist;
+       daddr_t lbn;
+       int i, len;
+
+       len = vp->v_lastw - vp->v_cstart + 1;
+       buflist = malloc(sizeof(struct buf *) * (len + 1) + sizeof(*buflist),
+           M_SEGMENT, M_WAITOK);
+       buflist->bs_nchildren = 0;
+       buflist->bs_children = (struct buf **)(buflist + 1);
+       for (lbn = vp->v_cstart, i = 0; i < len; lbn++, i++)
+                   (void)bread(vp, lbn, last_bp->b_bcount, NOCRED,
+                       &buflist->bs_children[i]);
+       buflist->bs_children[i] = last_bp;
+       buflist->bs_nchildren = i + 1;
+       return (buflist);

 }
 }