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=-14.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 5D273C43461 for ; Wed, 16 Sep 2020 08:31:38 +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 DE10F206DC for ; Wed, 16 Sep 2020 08:31:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="KN0b2RKB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DE10F206DC 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]:36714 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kISqm-00073Y-TE for qemu-devel@archiver.kernel.org; Wed, 16 Sep 2020 04:31:36 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59640) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kISnM-0002ZN-Cj for qemu-devel@nongnu.org; Wed, 16 Sep 2020 04:28:04 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:47454) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kISnJ-0005mK-C8 for qemu-devel@nongnu.org; Wed, 16 Sep 2020 04:28:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600244880; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=PIBbeaRry87iGA44wiTGBGij/hG+R7FSrF5Sa9Ju59Y=; b=KN0b2RKB3huCZQehtFGE3zs+XunApDa2lOGX+FBplb0SP78ElfA3swEWRZBzZuJDs70M4S MQ21k5CVhd8dq38t4czCF3hRve/PHjeDqLwf2GoxRC9sRXCm8Nf5L2NrK4WW5ZKu6Vh1HL N6MjO3JcdUvwjUctG6M18Qz/Qw9yc8A= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-480-GeUF0TFtOaqJ6oF6SmYLBw-1; Wed, 16 Sep 2020 04:27:58 -0400 X-MC-Unique: GeUF0TFtOaqJ6oF6SmYLBw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7588E8064B1; Wed, 16 Sep 2020 08:27:57 +0000 (UTC) Received: from redhat.com (ovpn-113-248.ams2.redhat.com [10.36.113.248]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A63A27839F; Wed, 16 Sep 2020 08:27:54 +0000 (UTC) Date: Wed, 16 Sep 2020 09:27:51 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Subject: Re: [PATCH v4 9/9] migration: introduce snapshot-{save, load, delete} QMP commands Message-ID: <20200916082751.GC1535709@redhat.com> References: <20200915113523.2520317-1-berrange@redhat.com> <20200915113523.2520317-10-berrange@redhat.com> <87tuvyt9sf.fsf@dusky.pond.sub.org> MIME-Version: 1.0 In-Reply-To: <87tuvyt9sf.fsf@dusky.pond.sub.org> User-Agent: Mutt/1.14.6 (2020-07-11) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Disposition: inline Received-SPF: pass client-ip=63.128.21.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/16 02:35:56 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -50 X-Spam_score: -5.1 X-Spam_bar: ----- X-Spam_report: (-5.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.999, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Kevin Wolf , Peter Krempa , "Denis V. Lunev" , qemu-block@nongnu.org, Juan Quintela , qemu-devel@nongnu.org, "Dr. David Alan Gilbert" , Pavel Dovgalyuk , Paolo Bonzini , Max Reitz , John Snow Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Sep 16, 2020 at 10:17:52AM +0200, Markus Armbruster wrote: > Daniel P. Berrangé writes: > > > savevm, loadvm and delvm are some of the few HMP commands that have never > > been converted to use QMP. The reasons for the lack of conversion are > > that they blocked execution of the event thread, and the semantics > > around choice of disks were ill-defined. > > > > Despite this downside, however, libvirt and applications using libvirt > > have used these commands for as long as QMP has existed, via the > > "human-monitor-command" passthrough command. IOW, while it is clearly > > desirable to be able to fix the problems, they are not a blocker to > > all real world usage. > > > > Meanwhile there is a need for other features which involve adding new > > parameters to the commands. This is possible with HMP passthrough, but > > it provides no reliable way for apps to introspect features, so using > > QAPI modelling is highly desirable. > > > > This patch thus introduces new snapshot-{load,save,delete} commands to > > QMP that are intended to replace the old HMP counterparts. The new > > commands are given different names, because they will be using the new > > QEMU job framework and thus will have diverging behaviour from the HMP > > originals. It would thus be misleading to keep the same name. > > > > While this design uses the generic job framework, the current impl is > > still blocking. The intention that the blocking problem is fixed later. > > None the less applications using these new commands should assume that > > they are asynchronous and thus wait for the job status change event to > > indicate completion. > > > > In addition to using the job framework, the new commands require the > > caller to be explicit about all the block device nodes used in the > > snapshot operations, with no built-in default heuristics in use. > > > > Signed-off-by: Daniel P. Berrangé > [...] > > diff --git a/qapi/job.json b/qapi/job.json > > index 280c2f76f1..b2cbb4fead 100644 > > --- a/qapi/job.json > > +++ b/qapi/job.json > > @@ -22,10 +22,17 @@ > > # > > # @amend: image options amend job type, see "x-blockdev-amend" (since 5.1) > > # > > +# @snapshot-load: snapshot load job type, see "snapshot-load" (since 5.2) > > +# > > +# @snapshot-save: snapshot save job type, see "snapshot-save" (since 5.2) > > +# > > +# @snapshot-delete: snapshot delete job type, see "snapshot-delete" (since 5.2) > > +# > > # Since: 1.7 > > ## > > { 'enum': 'JobType', > > - 'data': ['commit', 'stream', 'mirror', 'backup', 'create', 'amend'] } > > + 'data': ['commit', 'stream', 'mirror', 'backup', 'create', 'amend', > > + 'snapshot-load', 'snapshot-save', 'snapshot-delete'] } > > > > ## > > # @JobStatus: > > diff --git a/qapi/migration.json b/qapi/migration.json > > index 675f70bb67..b584c0be31 100644 > > --- a/qapi/migration.json > > +++ b/qapi/migration.json > > @@ -1720,3 +1720,123 @@ > > ## > > { 'event': 'UNPLUG_PRIMARY', > > 'data': { 'device-id': 'str' } } > > + > > +## > > +# @snapshot-save: > > +# > > +# Save a VM snapshot > > +# > > +# @job-id: identifier for the newly created job > > +# @tag: name of the snapshot to create > > +# @devices: list of block device node names to save a snapshot to > > Looks like you dropped the idea to also accept drive IDs. Is that for > good, or would you like to add it later? I'm still kind of on the fence, but if general opinion is that we should accept drive IDs, I'll add it. I wonder what the other blockdev-* APIs accept - some consistency between APIs is desirable. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|