From: Theodore Ts'o Subject: Re: [PATCH 2/2] ext4: implement cgroup writeback support Date: Wed, 23 Sep 2015 16:48:46 -0400 Message-ID: <20150923204846.GI3318@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> <20150923172535.GC25218@ret.masoncoding.com> <20150923175337.GD25218@ret.masoncoding.com> <20150923182432.GH3318@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Chris Mason , linux-ext4@vger.kernel.org, Johannes Weiner , axboe@kernel.dk, Tejun Heo , linux-fsdevel@vger.kernel.org, lizefan@huawei.com, cgroups@vger.kernel.org, adilger.kernel@dilger.ca, kernel-team@fb.com, "linux-kernel@vger.kernel.org" To: Artem Bityutskiy Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Wed, Sep 23, 2015 at 10:47:16PM +0300, Artem Bityutskiy wrote: > And, by the way, I forgot this detail - I cut AC power off at the > end, then put it back on after a 20 seconds delay. I mean, this is a > clean reboot, but with power cut at the end. Is this reproducible without the power cut? And what model SSD are you using, and are you sure that it has Power Loss Protection (many SSD vendors use power loss protection as the price discrimination feature between consumer-grade SSD and enterprise-grade SSD's that cost $$$). If this problem wasn't showing up with 4.2, and is only failing with 4.3-rcX, then it might not be a hardware issue --- but it's also possible that there was a timing issue which was hiding a hardware problem. So for the purposes of debugging, removing the power cut from the set of variables is a useful thing to do. - Ted