From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752222AbbIXINt (ORCPT ); Thu, 24 Sep 2015 04:13:49 -0400 Received: from mga01.intel.com ([192.55.52.88]:13331 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751478AbbIXINn (ORCPT ); Thu, 24 Sep 2015 04:13:43 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.17,580,1437462000"; d="scan'208";a="775932642" Message-ID: <1443082418.19983.238.camel@gmail.com> Subject: Re: [PATCH 2/2] ext4: implement cgroup writeback support From: Artem Bityutskiy Reply-To: dedekind1@gmail.com To: "Theodore Ts'o" 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" Date: Thu, 24 Sep 2015 11:13:38 +0300 In-Reply-To: <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> <20150923204846.GI3318@thunk.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.16.5 (3.16.5-1.fc22) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2015-09-23 at 16:48 -0400, Theodore Ts'o wrote: > 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, you are right that the problem may be anywhere, but since Tejun's patch fixes it, I decided to not spend time on testing without AC power cuts. But I checked and on of my boxes uses an HDD, and it shows the same problem, which makes the theory of imperfect SSD firmware being involved less likely. Thanks, Artem.