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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 BBB72C47404 for ; Fri, 11 Oct 2019 11:12:02 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 90D41206CD for ; Fri, 11 Oct 2019 11:12:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 90D41206CD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48510 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIsq1-0003Q0-JH for qemu-devel@archiver.kernel.org; Fri, 11 Oct 2019 07:12:01 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42192) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIsp7-0002rf-9g for qemu-devel@nongnu.org; Fri, 11 Oct 2019 07:11:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iIsp5-0004t3-01 for qemu-devel@nongnu.org; Fri, 11 Oct 2019 07:11:04 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56620) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iIsp4-0004sh-Qm for qemu-devel@nongnu.org; Fri, 11 Oct 2019 07:11:02 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 065B73065603; Fri, 11 Oct 2019 11:11:02 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.36.118.123]) by smtp.corp.redhat.com (Postfix) with ESMTPS id AB074196B2; Fri, 11 Oct 2019 11:11:01 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 2B22E1138619; Fri, 11 Oct 2019 13:10:54 +0200 (CEST) From: Markus Armbruster To: Kevin Wolf Subject: Re: [PATCH v2 2/2] qapi: Allow introspecting fix for savevm's cooperation with blockdev References: <992ea9ca130b4fb6dbf82726aa3b1d8040c16944.1568989362.git.pkrempa@redhat.com> <87r23w2rbp.fsf@dusky.pond.sub.org> <87a7ajuzpw.fsf@dusky.pond.sub.org> <20191010150733.GE7616@localhost.localdomain> <87r23jlsql.fsf@dusky.pond.sub.org> <20191011090036.GA5158@localhost.localdomain> Date: Fri, 11 Oct 2019 13:10:54 +0200 In-Reply-To: <20191011090036.GA5158@localhost.localdomain> (Kevin Wolf's message of "Fri, 11 Oct 2019 11:00:36 +0200") Message-ID: <8736fzfsg1.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.47]); Fri, 11 Oct 2019 11:11:02 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Krempa , qemu-devel@nongnu.org, Michael Roth Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Kevin Wolf writes: > Am 11.10.2019 um 08:08 hat Markus Armbruster geschrieben: >> Kevin Wolf writes: >> >> > Am 02.10.2019 um 13:57 hat Markus Armbruster geschrieben: [...] >> >> So the problem is certain (common & sane) -blockdev use makes savevm >> >> create additional, unwanted snapshots. >> > >> > Actually, the most common protocol driver is file-posix, which doesn't >> > support snapshots, so usually the result was that savevm just fails >> > because it can't snapshot something that it (incorrectly) thinks it >> > should snapshot. >> >> v3's commit message: >> >> qapi: Allow introspecting fix for savevm's cooperation with blockdev >> >> 'savevm' was buggy as it considered all monitor-owned block device nodes >> for snapshot. With introduction of -blockdev the common usage made all >> nodes including protocol and backing file nodes monitor-owned and thus >> considered for snapshot. >> >> This is a problem since the 'file' protocol nodes can't have internal >> snapshots and it does not make sense to take snapshot of nodes >> representing backing files. >> >> This was fixed by commit 05f4aced658a02b02 clients need to be able to >> detect whether this fix is present. > > Something is missing in this sentence. I think you lost the "but" from > the original message. I fixed this in v4 by inserting a period. I wasn't aware we had lost a "but". >> Since savevm does not have an QMP alternative, add the feature for the >> 'human-monitor-command' backdoor which is used to call this command in >> modern use. >> >> Signed-off-by: Peter Krempa >> >> Kevin, is this explanation sufficiently correct & complete? > > Looks good to me otherwise. Thanks!