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=-2.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 9B78AC3A59E for ; Sat, 24 Aug 2019 09:14:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6830920874 for ; Sat, 24 Aug 2019 09:14:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=web.de header.i=@web.de header.b="Nkr5IQAg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725906AbfHXJO2 (ORCPT ); Sat, 24 Aug 2019 05:14:28 -0400 Received: from mout.web.de ([212.227.15.4]:54935 "EHLO mout.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725798AbfHXJO2 (ORCPT ); Sat, 24 Aug 2019 05:14:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=web.de; s=dbaedf251592; t=1566638061; bh=4KdQ/v44B8Xvqa/bRTo/XlV3ScghQqfMmHlvkTOh+o8=; h=X-UI-Sender-Class:Subject:To:References:From:Date:In-Reply-To; b=Nkr5IQAg0bJEsDGTJlWviIj36d+dLxrO9fTrnotBG9skcD9cZlTiVAd0NYAHxDTpr d3i0MfI+ablhuKgguab6sXc1lggYlw5vpON9kRN/n57xTqI6f/UEBoHBBpSWuCwTy/ BCZNczlykTlQTDN30owSk4H7ytajj4jmTxoW47ws= X-UI-Sender-Class: c548c8c5-30a9-4db5-a2e7-cb6cb037b8f9 Received: from [172.16.2.20] ([81.27.118.244]) by smtp.web.de (mrweb002 [213.165.67.108]) with ESMTPSA (Nemesis) id 0MBkWd-1huXIQ09bD-00AkTJ; Sat, 24 Aug 2019 11:14:21 +0200 Subject: Re: [PATCH 0/5] block: loop: add file format subsystem and QCOW2 file format driver To: Bart Van Assche , development@manuel-bentele.de, linux-block@vger.kernel.org References: <20190823225619.15530-1-development@manuel-bentele.de> From: Manuel Bentele Message-ID: <4cc02259-24c0-0858-5439-5b1b0649d4f2@web.de> Date: Sat, 24 Aug 2019 11:14:20 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable Content-Language: de-DE X-Provags-ID: V03:K1:K5vlIrE0xsjfL+NSrINMBErA93mepHMs6U20ukuJK7+LBpQv2wK wDT5IW9c8ppyep+PpGCt9Q5wRal0881RseVaiPkx56brACWnS6Q/AI/WVKt3lb1vzJ6EFEL kKrQQzO7Gfe/qZ3aAO9MD9/8VEnamP6e5yWxqchZb1TvP/JAC9TJ/ZC2ePtlOyWqzim2VEK JyMGfAiBQRhw7NvXoK19A== X-UI-Out-Filterresults: notjunk:1;V03:K0:DedP4JSl3go=:e0o3t17IIh3t9AY05J6OCG gKT7Ae/1F6qyaIPQTbP3GjpCEdGW26e1kjQ5CB+kkhT1R6vE6PGslPptSarYMGFvs1lp98+JG ODmu/x0hP7UDWlsuWxXg21FjAS27YdUayx9/4HA/fDKyz4zoAyds8EVUCzI3TjrMb0K+uavai AtDVnEbETYuCHgLv+5QfjddZW2bw/NOkcRPuHhxaLfPDSOwX8X2eNQbQb8M+XZqsgYsIzcddl FZrtCi6/eRT5wCNsRMaOJOGFJ0r2y+zJYvqFUX90wmn/DtedbDuLPlr1QH6tmkWSHjlq1zb80 vxgN72bEFsV+y/jstxeljx7ptAzDxUj6ZVWDkHqfohoux8Ql6VnoaG54c3g9NK5K1pDgBwTwS Kj0SB4OTuv+LPNXeV/1qCRhaRgOjxehqzrlXu2kAgVimJyhyJIRVLFzfdEuU/omnfzTakJMxj nfWZrprf2pTtEpoxQqWul8JamY2OzMCXHeCXJ7rQAyhQAV+pETfK6NwcV0YMnAqi14HDvYfdI 2x+FSDAo+IlK1Snm2UcmndjBSsatM4T7tX4anQQYCboEUZ+CVJBDtRrSNr1Km7DYfwV11sR2c swxeD+71UiYaLPXaqeh0ZXL0H6s+UdQJc6/ThoQRg6XfOLfvv4gCwRzdRz0Wkj0oJPIbTW/gY Cd11z6MK91B3mdOkkKRRhOqcQ7FkarFnjuL6WzxZ6F3LGIDpXfHFGhfJPmnsHgEclobaSJx1U LUB3BRgaMGoShCQs41WB/a4WL5ljQij3fIQV+Gl0j1RVOozd6C7lfJ6u+EqHUAyLIB5QvP4bb 7ULqUTZZvfbm3ASOSfl8s3Gm19EdhnOauA/1/meSaGw7bQikgn2vZ1wG44pxNsvL4HzJH3FIZ Ll6CgH5QPhlOtUXQhhG1f4jFdY5uhPtjKKWP+GLTm5liX5JV4k3oYSnbYSjFvPeFOhOKKj8S3 YOLl5AjH3MGD1ZodLqeNw+sqgjhgCYNiIYTYcorh0TK+LubLrQxhfuPeg6HkCmmWuekoEj+1L A8KB1qXzB8K+2PmGniOZL5Qmh7ZiZgEgyUiuNrugWYpcO4OrUDciZUKeD/emvBw1K9HwpQgil wkCXYnvsc1X5kghR+AuTmGjUGOEC2taP9HW56RPCgKdnxrQwYEUiylIH3WAiBSMJ/fra8AmH7 ZtUyk= Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi Bart Thanks for your quick reply. On 8/24/19 5:37 AM, Bart Van Assche wrote: > On 8/23/19 3:56 PM, development@manuel-bentele.de wrote: >> During the discussion, it turned out that the implementation as device >> mapper target is not applicable. The device mapper stacks different >> functionality such as compression or encryption on multiple block devic= e >> layers whereas an implementation for the QCOW2 container format provide= s >> these functionalities on one block device layer. > > Hi Manuel, > > Is there a more detailed discussion available of this subject? No, the only discussion is the referenced one [1]. But there was a similar discussion in the master's thesis of Francesc Zacarias Ribot [2]. Unfortunately, I found no attempt on the mailing list that proposes his solution. > Are you familiar with the dm-crypt driver? I don't know the specific implementation details, but I use this driver personally and I like it. Do you want to propose that only the storage aspect of the QCOW2 container format should be used and all other functionality inside the container should be provided by available device mapper targets? > [...] Regards, Manuel [1] https://www.spinics.net/lists/linux-block/msg39538.html [2] Francesc Zacarias Ribot: QLOOP Linux driver to mount QCOW2 virtual disks; June 23, 2010; https://upcommons.upc.edu/bitstream/handle/2099.1/9619/65757.pdf