From: Pavel Machek Subject: Re: [Bug 14354] Re: ext4 increased intolerance to unclean shutdown? Date: Sun, 25 Oct 2009 07:22:02 +0100 Message-ID: <20091025062202.GB1391@ucw.cz> References: <20091016091558.GA10184@mit.edu> <4AD8C679.3030300@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Theodore Tso , Parag Warudkar , LKML , linux-ext4@vger.kernel.org, bugzilla-daemon@bugzilla.kernel.org To: Ric Wheeler Return-path: Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:40175 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753682AbZJYTEM (ORCPT ); Sun, 25 Oct 2009 15:04:12 -0400 Content-Disposition: inline In-Reply-To: <4AD8C679.3030300@redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Hi! >>> So I have been experimenting with various root file systems on my >>> laptop running latest git. This laptop some times has problems waking >>> up from sleep and that results in it needing a hard reset and >>> subsequently unclean file system. >>> >> A number of people have reported this, and there is some discussion >> and some suggestions that I've made here: >> >> http://bugzilla.kernel.org/show_bug.cgi?id=14354 >> >> It's been very frustrating because I have not been able to replicate >> it myself; I've been very much looking for someone who is (a) willing >> to work with me on this, and perhaps willing to risk running fsck >> frequently, perhaps after every single unclean shutdown, and (b) who >> can reliably reproduce this problem. On my system, which is a T400 >> running 9.04 with the latest git kernels, I've not been able to >> reproduce it, despite many efforts to try to reproduce it. (i.e., >> suspend the machine and then pull the battery and power; pulling the >> battery and power, "echo c> /proc/sysrq-trigger", etc., while >> doing "make -j4" when the system is being uncleanly shutdown) >> > > I wonder if we might have better luck if we tested using an external > (e-sata or USB connected) S-ATA drive. > > Instead of pulling the drive's data connection, most of these have an > external power source that could be turned off so the drive firmware > won't have a chance to flush the volatile write cache. Note that some > drives automatically write back the cache if they have power and see a > bus disconnect, so hot unplugging just the e-sata or usb cable does not > do the trick. > > Given the number of cheap external drives, this should be easy to test > at home.... Do they support barriers? (Anyway, you may want to use some kind of VM for testing. That should make the testing cycle shorter, easier to reprorduce *and* more repeatable.) Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html