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[209.132.180.67]) by mx.google.com with ESMTP id t18-v6si4091121plo.191.2018.08.03.13.09.55; Fri, 03 Aug 2018 13:10:09 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732197AbeHCWGG (ORCPT + 99 others); Fri, 3 Aug 2018 18:06:06 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:53218 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728477AbeHCWGG (ORCPT ); Fri, 3 Aug 2018 18:06:06 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 0D726401EF0B; Fri, 3 Aug 2018 20:08:19 +0000 (UTC) Received: from agk-dp.fab.redhat.com (agk-dp.fab.redhat.com [10.33.15.10]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6E6D72026D65; Fri, 3 Aug 2018 20:08:18 +0000 (UTC) Received: from agk by agk-dp.fab.redhat.com with local (Exim 4.69) (envelope-from ) id 1flgMz-0008Hx-97; Fri, 03 Aug 2018 21:08:17 +0100 Date: Fri, 3 Aug 2018 21:08:17 +0100 From: Alasdair G Kergon To: "Theodore Y. Ts'o" , Mike Snitzer , Linus Torvalds , Jens Axboe , Sagi Grimberg , Linux Kernel Mailing List , linux-block , dm-devel@redhat.com, Ilya Dryomov , wgh@torlan.ru, Zdenek Kabelac Subject: Re: [dm-devel] LVM snapshot broke between 4.14 and 4.16 Message-ID: <20180803200817.GB31444@agk-dp.fab.redhat.com> Mail-Followup-To: "Theodore Y. Ts'o" , Mike Snitzer , Linus Torvalds , Jens Axboe , Sagi Grimberg , Linux Kernel Mailing List , linux-block , dm-devel@redhat.com, Ilya Dryomov , wgh@torlan.ru, Zdenek Kabelac References: <93bff248-6897-4867-841b-2dace11597de@torlan.ru> <1ec0a220-d5b0-1c27-e63b-c4d3f4ce9d77@torlan.ru> <20180803133102.GA3092@redhat.com> <20180803152034.GD32066@thunk.org> <20180803195636.GA31444@agk-dp.fab.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180803195636.GA31444@agk-dp.fab.redhat.com> Organization: Red Hat UK Ltd. Registered in England and Wales, number 03798903. Registered Office: Peninsular House, 30-36 Monument Street, 4th Floor, London, England, EC3R 8NB. User-Agent: Mutt/1.5.18 (2008-05-17) X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Fri, 03 Aug 2018 20:08:19 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Fri, 03 Aug 2018 20:08:19 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'agk@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 03, 2018 at 08:56:36PM +0100, Alasdair G Kergon wrote: > Anything passing in version 4.37.0 or earlier (which is the version in If taking this approach, it might be better to use the current version i.e. where we add the kernel-side fix. IOW anything compiling against a uapi header taken from a kernel up to now will see the old behaviour, but anything newer (after we next increment the kernel dm version) will be required to change its userspace code if it has this problem in it. The problematic versions of lvm2 ship with versions up to and including 4.36.0 in this field so should be caught either way. Alasdair