diff --git a/sys/kern/vfs_cluster.c b/sys/kern/vfs_cluster.c
index 9c8b143429b4..3a26e170c8c7 100644
--- a/sys/kern/vfs_cluster.c
+++ b/sys/kern/vfs_cluster.c
@@ -33,7 +33,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)vfs_cluster.c	8.7 (Berkeley) 2/13/94
- * $Id: vfs_cluster.c,v 1.43 1997/03/07 14:40:54 dyson Exp $
+ * $Id: vfs_cluster.c,v 1.44 1997/04/01 11:48:30 bde Exp $
  */
 
 #include <sys/param.h>
@@ -468,6 +468,7 @@ cluster_callback(bp)
 			tbp->b_flags |= B_ERROR;
 			tbp->b_error = error;
 		}
+		tbp->b_dirtyoff = tbp->b_dirtyend = 0;
 		biodone(tbp);
 	}
 	relpbuf(bp);
diff --git a/sys/nfs/nfs_bio.c b/sys/nfs/nfs_bio.c
index b5912b585724..a63fd78390e6 100644
--- a/sys/nfs/nfs_bio.c
+++ b/sys/nfs/nfs_bio.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)nfs_bio.c	8.9 (Berkeley) 3/30/95
- * $Id: nfs_bio.c,v 1.33 1997/03/09 10:21:26 bde Exp $
+ * $Id: nfs_bio.c,v 1.34 1997/04/03 07:52:00 dfr Exp $
  */
 
 
@@ -962,9 +962,12 @@ nfs_doio(bp, cr, p)
 		    iomode = NFSV3WRITE_FILESYNC;
 		bp->b_flags |= B_WRITEINPROG;
 		error = nfs_writerpc(vp, uiop, cr, &iomode, &must_commit);
-		if (!error && iomode == NFSV3WRITE_UNSTABLE)
-		    bp->b_flags |= B_NEEDCOMMIT | B_CLUSTEROK;
-		else
+		if (!error && iomode == NFSV3WRITE_UNSTABLE) {
+		    bp->b_flags |= B_NEEDCOMMIT;
+		    if (bp->b_dirtyoff == 0
+			&& bp->b_dirtyend == bp->b_bufsize)
+			bp->b_flags |= B_CLUSTEROK;
+		} else
 		    bp->b_flags &= ~B_NEEDCOMMIT;
 		bp->b_flags &= ~B_WRITEINPROG;
 
diff --git a/sys/nfsclient/nfs_bio.c b/sys/nfsclient/nfs_bio.c
index b5912b585724..a63fd78390e6 100644
--- a/sys/nfsclient/nfs_bio.c
+++ b/sys/nfsclient/nfs_bio.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)nfs_bio.c	8.9 (Berkeley) 3/30/95
- * $Id: nfs_bio.c,v 1.33 1997/03/09 10:21:26 bde Exp $
+ * $Id: nfs_bio.c,v 1.34 1997/04/03 07:52:00 dfr Exp $
  */
 
 
@@ -962,9 +962,12 @@ nfs_doio(bp, cr, p)
 		    iomode = NFSV3WRITE_FILESYNC;
 		bp->b_flags |= B_WRITEINPROG;
 		error = nfs_writerpc(vp, uiop, cr, &iomode, &must_commit);
-		if (!error && iomode == NFSV3WRITE_UNSTABLE)
-		    bp->b_flags |= B_NEEDCOMMIT | B_CLUSTEROK;
-		else
+		if (!error && iomode == NFSV3WRITE_UNSTABLE) {
+		    bp->b_flags |= B_NEEDCOMMIT;
+		    if (bp->b_dirtyoff == 0
+			&& bp->b_dirtyend == bp->b_bufsize)
+			bp->b_flags |= B_CLUSTEROK;
+		} else
 		    bp->b_flags &= ~B_NEEDCOMMIT;
 		bp->b_flags &= ~B_WRITEINPROG;