From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C25AC28CF6 for ; Fri, 3 Aug 2018 13:31:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3B1922175D for ; Fri, 3 Aug 2018 13:31:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3B1922175D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732222AbeHCP11 (ORCPT ); Fri, 3 Aug 2018 11:27:27 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:41924 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1729630AbeHCP10 (ORCPT ); Fri, 3 Aug 2018 11:27:26 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 30C6140216F9; Fri, 3 Aug 2018 13:31:04 +0000 (UTC) Received: from localhost (unknown [10.18.25.149]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A07E620389E0; Fri, 3 Aug 2018 13:31:03 +0000 (UTC) Date: Fri, 3 Aug 2018 09:31:03 -0400 From: Mike Snitzer To: Linus Torvalds Cc: wgh@torlan.ru, Ilya Dryomov , Jens Axboe , linux-block , Linux Kernel Mailing List , Sagi Grimberg , dm-devel@redhat.com Subject: Re: LVM snapshot broke between 4.14 and 4.16 Message-ID: <20180803133102.GA3092@redhat.com> References: <226835ba-2197-b850-6e5b-8ba14f7fd016@torlan.ru> <93bff248-6897-4867-841b-2dace11597de@torlan.ru> <1ec0a220-d5b0-1c27-e63b-c4d3f4ce9d77@torlan.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Fri, 03 Aug 2018 13:31:04 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.5]); Fri, 03 Aug 2018 13:31:04 +0000 (UTC) for IP:'10.11.54.6' DOMAIN:'int-mx06.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'msnitzer@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 02 2018 at 5:52pm -0400, Linus Torvalds wrote: > On Thu, Aug 2, 2018 at 2:39 PM WGH wrote: > > > > I've just found one public report of this bug, though: > > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=900442 > > Yeah, it does sound like we should fix this issue. Debian is notorious for having a stale and/or custom lvm2. Generally speaking, it is recommended that lvm2 not be older than the kernel (but the opposite is fine). Given the narrow scope of users impacted (read-only snapshot creation is very niche, certainly not the default): I don't think it is worth making fiddly changes in dm-snapshot to warn the user and override the permissions for the cow device. Mike