From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: Re: xfstests 073 regression Date: Mon, 1 Aug 2011 13:24:14 +0800 Message-ID: <20110801052414.GA21021@localhost> References: <20110728164105.GA18258@infradead.org> <20110729142121.GA21149@localhost> <20110730134422.GA1884@infradead.org> <20110731151014.GA23106@localhost> <20110731234749.GQ5404@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linus Torvalds , Christoph Hellwig , Jan Kara , Andrew Morton , "linux-fsdevel@vger.kernel.org" , LKML To: Dave Chinner Return-path: Received: from mga01.intel.com ([192.55.52.88]:10438 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752668Ab1HAFYR (ORCPT ); Mon, 1 Aug 2011 01:24:17 -0400 Content-Disposition: inline In-Reply-To: <20110731234749.GQ5404@dastard> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Mon, Aug 01, 2011 at 07:47:49AM +0800, Dave Chinner wrote: > On Sun, Jul 31, 2011 at 11:10:14PM +0800, Wu Fengguang wrote: > > On Sat, Jul 30, 2011 at 09:44:22PM +0800, Christoph Hellwig wrote: > > > This patch fixes the hang for me. > > > > Thanks. It'd be better to get the _simple and tested_ fix into 3.1-rc1. > > (if anyone find major problems with the fix, please speak up) > > Yes, I already have, a couple of hours before you sent this: > > http://www.spinics.net/lists/linux-fsdevel/msg47357.html Err I found it in my spam folder.. and added you to the white list :) > We haven't found the root cause of the problem, and writeback cannot > hold off grab_super_passive() because writeback only holds read > locks on s_umount, just like grab_super_passive. So if > grab_super_passive is failing, there is some other, not yet > unidentified actor causing this problem.... Yeah sorry, I totally overlooked the read lock. Since Linus has pointed out the possibility of read-write-read deadlock, I'll jump to your more recent email for the root cause. Thanks, Fengguang