From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ted Ts'o Subject: Re: [PATCH] ext4: fix freeze deadlock under IO Date: Sun, 1 Aug 2010 17:41:32 -0400 Message-ID: <20100801214132.GA27573@thunk.org> References: <4C1A2839.5010407@cfl.rr.com> <20100617142731.GA10071@redhat.com> <4C1A4A74.9070105@cfl.rr.com> <20100617162747.GA21336@redhat.com> <4C1ACBF1.3050603@cfl.rr.com> <4C1BC125.4090902@sandeen.net> <4C1BC6D0.2030203@sandeen.net> <4C1BC7AD.1060900@sandeen.net> <4C226277.4060505@sandeen.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Phillip Susi , Mike Snitzer , device-mapper development , linux-fsdevel@vger.kernel.org, Eric Sandeen , ext4 development , Dave Chinner To: Eric Sandeen Return-path: Content-Disposition: inline In-Reply-To: <4C226277.4060505@sandeen.net> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Wed, Jun 23, 2010 at 02:37:27PM -0500, Eric Sandeen wrote: > Commit 6b0310fbf087ad6 caused a regression resulting in deadlocks > when freezing a filesystem which had active IO; the vfs_check_frozen > level (SB_FREEZE_WRITE) did not let the freeze-related IO syncing > through. Duh. > > Changing the test to FREEZE_TRANS should let the normal freeze > syncing get through the fs, but still block any transactions from > starting once the fs is completely frozen. > > I tested this by running fsstress in the background while periodically > snapshotting the fs and running fsck on the result. I ran into > occasional deadlocks, but different ones. I think this is a > fine fix for the problem at hand, and the other deadlocky things > will need more investigation. > > Reported-by: Phillip Susi > Signed-off-by: Eric Sandeen Applied to the ext4 patch queue. Sorry for missing this earier. - Ted