From owner-svn-src-stable-9@FreeBSD.ORG  Wed Apr  3 15:38:45 2013
Return-Path: <owner-svn-src-stable-9@FreeBSD.ORG>
Delivered-To: svn-src-stable-9@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by hub.freebsd.org (Postfix) with ESMTP id 297972E3;
 Wed,  3 Apr 2013 15:38:45 +0000 (UTC) (envelope-from kib@FreeBSD.org)
Received: from svn.freebsd.org (svn.freebsd.org
 [IPv6:2001:1900:2254:2068::e6a:0])
 by mx1.freebsd.org (Postfix) with ESMTP id 1A1BAA8D;
 Wed,  3 Apr 2013 15:38:45 +0000 (UTC)
Received: from svn.freebsd.org ([127.0.1.70])
 by svn.freebsd.org (8.14.6/8.14.6) with ESMTP id r33FciOS078905;
 Wed, 3 Apr 2013 15:38:44 GMT (envelope-from kib@svn.freebsd.org)
Received: (from kib@localhost)
 by svn.freebsd.org (8.14.6/8.14.5/Submit) id r33FciW4078904;
 Wed, 3 Apr 2013 15:38:44 GMT (envelope-from kib@svn.freebsd.org)
Message-Id: <201304031538.r33FciW4078904@svn.freebsd.org>
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Wed, 3 Apr 2013 15:38:44 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org
Subject: svn commit: r249054 - stable/9/sys/kern
X-SVN-Group: stable-9
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
X-BeenThere: svn-src-stable-9@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: SVN commit messages for only the 9-stable src tree
 <svn-src-stable-9.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/svn-src-stable-9>, 
 <mailto:svn-src-stable-9-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-stable-9>
List-Post: <mailto:svn-src-stable-9@freebsd.org>
List-Help: <mailto:svn-src-stable-9-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/svn-src-stable-9>, 
 <mailto:svn-src-stable-9-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 03 Apr 2013 15:38:45 -0000

Author: kib
Date: Wed Apr  3 15:38:44 2013
New Revision: 249054
URL: http://svnweb.freebsd.org/changeset/base/249054

Log:
  MFC r248563:
  Increment the write ref counter for the buffer object before calling
  bundirty().

Modified:
  stable/9/sys/kern/vfs_bio.c
Directory Properties:
  stable/9/sys/   (props changed)

Modified: stable/9/sys/kern/vfs_bio.c
==============================================================================
--- stable/9/sys/kern/vfs_bio.c	Wed Apr  3 15:34:25 2013	(r249053)
+++ stable/9/sys/kern/vfs_bio.c	Wed Apr  3 15:38:44 2013	(r249054)
@@ -936,7 +936,13 @@ bufwrite(struct buf *bp)
 	else
 		vp_md = 0;
 
-	/* Mark the buffer clean */
+	/*
+	 * Mark the buffer clean.  Increment the bufobj write count
+	 * before bundirty() call, to prevent other thread from seeing
+	 * empty dirty list and zero counter for writes in progress,
+	 * falsely indicating that the bufobj is clean.
+	 */
+	bufobj_wref(bp->b_bufobj);
 	bundirty(bp);
 
 	bp->b_flags &= ~B_DONE;
@@ -944,7 +950,6 @@ bufwrite(struct buf *bp)
 	bp->b_flags |= B_CACHE;
 	bp->b_iocmd = BIO_WRITE;
 
-	bufobj_wref(bp->b_bufobj);
 	vfs_busy_pages(bp, 1);
 
 	/*