Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756689Ab0HaJze (ORCPT ); Tue, 31 Aug 2010 05:55:34 -0400 Received: from daytona.panasas.com ([67.152.220.89]:53449 "EHLO daytona.int.panasas.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751183Ab0HaJzc (ORCPT ); Tue, 31 Aug 2010 05:55:32 -0400 Message-ID: <4C7CD18B.2060608@panasas.com> Date: Tue, 31 Aug 2010 12:55:23 +0300 From: Boaz Harrosh User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-2.fc12 Thunderbird/3.0.4 MIME-Version: 1.0 To: Jan Kara CC: Vladislav Bolkhovitin , Jeff Moyer , Tejun Heo , Christoph Hellwig , jaxboe@fusionio.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-scsi@vger.kernel.org, linux-ide@vger.kernel.org, linux-raid@vger.kernel.org, James.Bottomley@suse.de, tytso@mit.edu, chris.mason@oracle.com, swhiteho@redhat.com, konishi.ryusuke@lab.ntt.co.jp, dm-devel@redhat.com, rwheeler@redhat.com, hare@suse.de, neilb@suse.de, rusty@rustcorp.com.au, mst@redhat.com, jeremy@goop.org, snitzer@redhat.com, k-ueda@ct.jp.nec.com, Christoph Hellwig Subject: Re: [PATCH 26/30] ext4: do not send discards as barriers References: <1282751267-3530-27-git-send-email-tj@kernel.org> <20100825155842.GA3229@lst.de> <20100825160032.GC3229@lst.de> <4C753D75.2010305@kernel.org> <20100825200223.GE2738@quack.suse.cz> <4C76250B.6060800@kernel.org> <20100827173147.GA12374@quack.suse.cz> <20100830202034.GB12226@quack.quadriga.com> <4C7C170D.9090409@vlnb.net> <20100830210205.GD12226@quack.quadriga.com> In-Reply-To: <20100830210205.GD12226@quack.quadriga.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 31 Aug 2010 09:55:31.0417 (UTC) FILETIME=[A5FB0C90:01CB48F2] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1814 Lines: 44 On 08/31/2010 12:02 AM, Jan Kara wrote: > On Tue 31-08-10 00:39:41, Vladislav Bolkhovitin wrote: >> Jan Kara, on 08/31/2010 12:20 AM wrote: >>> On Mon 30-08-10 15:56:43, Jeff Moyer wrote: >>>> Jan Kara writes: >>>> >>>>> An update: I've set up an ext4 barrier testing in KVM - run fsstress, >>>>> kill KVM at some random moment and check that the filesystem is consistent >>>>> (kvm is run in cache=writeback mode to simulate disk cache). About 70 runs >>>> >>>> But doesn't your "disk cache" survive the "power cycle" of your guest? >>> Yes, you're right. Thinking about it now the test setup was wrong because >>> it didn't refuse writes to the VM's data partition after the moment I >>> killed KVM. Thanks for catching this. I will probably have to use the fault >>> injection on the host to disallow writing the device at a certain moment. >>> Or does somebody have a better option? >> >> Have you considered to setup a second box as an iSCSI target (e.g. >> with iSCSI-SCST)? With it killing the connectivity is just a matter >> of a single iptables command + a lot more options. Still same problem no? the data is still cached on the backing store device how do you trash the cached data? > Hmm, this might be an interesting option. Will try that. Thanks for > suggestion. > > Honza with stgt it's very simple as well. It's a user mode application. All on the same machine: - run stgt application - login + mount a filesystem - run test - kill -9 stgt mid flight But how to throw away the data on the backing store cache? Boaz -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/