From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: [Lsf-pc] [LSF/MM TOPIC] Working towards better power fail testing Date: Wed, 10 Dec 2014 12:27:59 +0100 Message-ID: <20141210112759.GC25671@quack.suse.cz> References: <5486221D.6000006@fb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org To: Josef Bacik Return-path: Received: from cantor2.suse.de ([195.135.220.15]:39164 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751817AbaLJL2F (ORCPT ); Wed, 10 Dec 2014 06:28:05 -0500 Content-Disposition: inline In-Reply-To: <5486221D.6000006@fb.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Mon 08-12-14 17:11:41, Josef Bacik wrote: > Hello, > > We have been doing pretty well at populating xfstests with loads of > tests to catch regressions and validate we're all working properly. > One thing that has been lacking is a good way to verify file system > integrity after a power fail. This is a core part of what file > systems are supposed to provide but it is probably the least tested > aspect. We have dm-flakey tests in xfstests to test fsync > correctness, but these tests do not catch the random horrible things > that can go wrong. We are still finding horrible scary things that > go wrong in Btrfs because it is simply hard to reproduce and test > for. > > I have been working on an idea to do this better, some may have seen > my dm-power-fail attempt, and I've got a new incarnation of the idea > thanks to discussions with Zach Brown. Obviously there will be a > lot changing in this area in the time between now and March but it > would be good to have everybody in the room talking about what they > would need to build a good and deterministic test to make sure we're > always giving a consistent file system and to make sure our fsync() > handling is working properly. Thanks, I agree we are lacking in testing this aspect. Just I don't see too much material for discussion there, unless we have something more tangible - when we have some implementation, we can talk about pros and cons of it, what still needs doing etc. Honza -- Jan Kara SUSE Labs, CR