From: Theodore Ts'o Subject: Re: [PATCH 2/2] ext4: implement cgroup writeback support Date: Wed, 23 Sep 2015 13:02:38 -0400 Message-ID: <20150923170238.GG3318@thunk.org> References: <1434495193-31182-1-git-send-email-tj@kernel.org> <1434495193-31182-3-git-send-email-tj@kernel.org> <20150722035620.GD2944@thunk.org> <1443012552.19983.209.camel@gmail.com> <1443016253.19983.230.camel@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Tejun Heo , axboe@kernel.dk, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, lizefan@huawei.com, cgroups@vger.kernel.org, hannes@cmpxchg.org, kernel-team@fb.com, adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org To: Artem Bityutskiy Return-path: Content-Disposition: inline In-Reply-To: <1443016253.19983.230.camel@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Wed, Sep 23, 2015 at 04:50:53PM +0300, Artem Bityutskiy wrote: > On Wed, 2015-09-23 at 15:49 +0300, Artem Bityutskiy wrote: > > On Tue, 2015-07-21 at 23:56 -0400, Theodore Ts'o wrote: > > > > v2: Updated for MS_CGROUPWB -> SB_I_CGROUPWB. > > > > > > > > Signed-off-by: Tejun Heo > > > > Cc: "Theodore Ts'o" > > > > Cc: Andreas Dilger > > > > Cc: linux-ext4@vger.kernel.org > > > > > > Thanks, applied. > > > > Hi, this patch introduces a regression - a major one, I'd say. > > > > Symptoms: copy a bunch of file, run sync, then run 'reboot', and > > after > > you boot up the copied files are corrupted. So basically the user > > -visible symptom is that 'sync' does not work. > > Just FYI, this is the issue I briefly reported last Fri: > > https://lkml.org/lkml/2015/9/18/640 Also note this performance regression reported by Dexuan Cui https://lkml.org/lkml/2015/9/23/333 I didn't notice these problems since I my userspace doesn't enable the writeback cgroup. (In fact I don't know how to do it using Debian Jessie.) Tejun, can you please take a look at this and give me a recommendation? I'm willing to wait a day or two while we try to fix the problem, but past that point I'd like to have a fix or revert this commit before Linus releases the next -rc release. - Ted