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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 65741C433E0 for ; Wed, 20 Jan 2021 18:58:59 +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 BC488233EB for ; Wed, 20 Jan 2021 18:58:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BC488233EB 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]:36642 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l2Igz-0005nW-I2 for qemu-devel@archiver.kernel.org; Wed, 20 Jan 2021 13:58:57 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:40802) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l2IgH-0005A6-RQ for qemu-devel@nongnu.org; Wed, 20 Jan 2021 13:58:13 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:43645) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1l2IgE-0005BS-My for qemu-devel@nongnu.org; Wed, 20 Jan 2021 13:58:12 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1611169089; h=from:from: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=OZ0AgHvlI40a6eLzhK6w3j+Yu4+OXhi+1PpwkIw99tw=; b=Dyk//NCNOMsl1+MoihS1Rp9PcPZeGUccMBygynfDggkaALoFUkLEQRAPMvBhUM+hjuXYPV eaYY8SlhYKAJ8tb8BiySonvX3wl+juGij3xw/MODqMpukYrjbanc+bc9728mxeimNVAKEn ONsLXNPSlVB81rXYZpOSYaoRCZ6WMW8= 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-10-X-FhDpcKPM24_8vI663FlQ-1; Wed, 20 Jan 2021 13:58:07 -0500 X-MC-Unique: X-FhDpcKPM24_8vI663FlQ-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 430BA107ACE3; Wed, 20 Jan 2021 18:58:06 +0000 (UTC) Received: from [10.3.113.116] (ovpn-113-116.phx2.redhat.com [10.3.113.116]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3D62819CB1; Wed, 20 Jan 2021 18:58:05 +0000 (UTC) To: =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= , qemu-devel@nongnu.org References: <20210120104411.3084801-1-berrange@redhat.com> <20210120104411.3084801-12-berrange@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Subject: Re: [PATCH v9 11/11] migration: introduce snapshot-{save, load, delete} QMP commands Message-ID: <5226cddb-3b3f-6cb6-c1c9-d943e495df72@redhat.com> Date: Wed, 20 Jan 2021 12:58:04 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20210120104411.3084801-12-berrange@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=eblake@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -23 X-Spam_score: -2.4 X-Spam_bar: -- X-Spam_report: (-2.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.167, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.094, RCVD_IN_DNSWL_NONE=-0.0001, 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: , Cc: Kevin Wolf , qemu-block@nongnu.org, Juan Quintela , Markus Armbruster , Max Reitz , Pavel Dovgalyuk , Paolo Bonzini , John Snow , "Dr. David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 1/20/21 4:44 AM, Daniel P. Berrangé wrote: > 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. > > Note that the existing "query-named-block-nodes" can be used to query > what snapshots currently exist for block nodes. > > Acked-by: Markus Armbruster > Signed-off-by: Daniel P. Berrangé > --- > +++ b/migration/savevm.c > @@ -2968,7 +2968,7 @@ bool load_snapshot(const char *name, const char *vmstate, > if (ret == 0) { > error_setg(errp, "Snapshot '%s' does not exist in one or more devices", > name); > - return -1; > + return false; This hunk belongs in 6/11. > +++ 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) s/5.2/6.0/g > +++ b/qapi/migration.json > @@ -1843,3 +1843,124 @@ > # Since: 5.2 > ## > { 'command': 'query-dirty-rate', 'returns': 'DirtyRateInfo' } > + > +## > +# @snapshot-save: > +# > +# Save a VM snapshot > +# > +# @job-id: identifier for the newly created job > +# @tag: name of the snapshot to create > +# @vmstate: block device node name to save vmstate to > +# @devices: list of block device node names to save a snapshot to > +# > +# Applications should not assume that the snapshot save is complete > +# when this command returns. The job commands / events must be used > +# to determine completion and to fetch details of any errors that arise. > +# > +# Note that execution of the guest CPUs may be stopped during the > +# time it takes to save the snapshot. A future version of QEMU > +# may ensure CPUs are executing continuously. > +# > +# It is strongly recommended that @devices contain all writable > +# block device nodes if a consistent snapshot is required. > +# > +# If @tag already exists, an error will be reported > +# > +# Returns: nothing > +# > +# Example: > +# > +# -> { "execute": "snapshot-save", > +# "data": { > +# "job-id": "snapsave0", > +# "tag": "my-snap", > +# "vmstate": "disk0", > +# "devices": ["disk0", "disk1"] > +# } > +# } > +# <- { "return": { } } > +# > +# Since: 6.0 The example would be wise to further show waiting for the job completion event. > +## > +{ 'command': 'snapshot-save', > + 'data': { 'job-id': 'str', > + 'tag': 'str', > + 'vmstate': 'str', > + 'devices': ['str'] } } > + > +## > +# @snapshot-load: > +# > +# Load a VM snapshot > +# > +# @job-id: identifier for the newly created job > +# @tag: name of the snapshot to load. > +# @vmstate: block device node name to load vmstate from > +# @devices: list of block device node names to load a snapshot from > +# > +# Applications should not assume that the snapshot load is complete > +# when this command returns. The job commands / events must be used > +# to determine completion and to fetch details of any errors that arise. > +# > +# Note that execution of the guest CPUs will be stopped during the > +# time it takes to load the snapshot. > +# > +# It is strongly recommended that @devices contain all writable > +# block device nodes that can have changed since the original > +# @snapshot-save command execution. > +# > +# Returns: nothing > +# > +# Example: > +# > +# -> { "execute": "snapshot-load", > +# "data": { > +# "job-id": "snapload0", > +# "tag": "my-snap", > +# "vmstate": "disk0", > +# "devices": ["disk0", "disk1"] > +# } > +# } > +# <- { "return": { } } > +# Here as well. > +# Since: 6.0 > +## > +{ 'command': 'snapshot-load', > + 'data': { 'job-id': 'str', > + 'tag': 'str', > + 'vmstate': 'str', > + 'devices': ['str'] } } > + > +## > +# @snapshot-delete: > +# > +# Delete a VM snapshot > +# > +# @job-id: identifier for the newly created job > +# @tag: name of the snapshot to delete. > +# @devices: list of block device node names to delete a snapshot from > +# > +# Applications should not assume that the snapshot save is complete > +# when this command returns. The job commands / events must be used > +# to determine completion and to fetch details of any errors that arise. > +# > +# Returns: nothing > +# > +# Example: > +# > +# -> { "execute": "snapshot-delete", > +# "data": { > +# "job-id": "snapdelete0", > +# "tag": "my-snap", > +# "devices": ["disk0", "disk1"] > +# } > +# } > +# <- { "return": { } } > +# > +# Since: 6.0 > +## > +{ 'command': 'snapshot-delete', > + 'data': { 'job-id': 'str', > + 'tag': 'str', > + 'devices': ['str'] } } > diff --git a/slirp b/slirp > index 8f43a99191..ce94eba204 160000 > --- a/slirp > +++ b/slirp > @@ -1 +1 @@ > -Subproject commit 8f43a99191afb47ca3f3c6972f6306209f367ece > +Subproject commit ce94eba2042d52a0ba3d9e252ebce86715e94275 Oops. This shouldn't be here. > diff --git a/tests/qemu-iotests/310 b/tests/qemu-iotests/310 > new file mode 100755 > index 0000000000..41cec9ea8d > --- /dev/null > +++ b/tests/qemu-iotests/310 > @@ -0,0 +1,385 @@ > +#!/usr/bin/env bash > +# > +# Test which nodes are involved in internal snapshots > +# > +# Copyright (C) 2020 Red Hat, Inc. Worth also mentioning 2021? > + # Next events vary depending on job type and > + # whether it succeeds or not. > + for evname in $@ > + do > + _wait_event $QEMU_HANDLE $evname TAB damage throughout this file. > +echo > +echo "===== Snapshot dual qcow2 image =====" > +echo > + > +# We can snapshot multiple qcow2 disks at the same time extra space > +++ b/tests/qemu-iotests/group > @@ -318,4 +318,5 @@ > 307 rw quick export > 308 rw > 309 rw auto quick > +310 rw quick > 312 rw quick Vladimir's work to get rid of the 'group' file will be a trivial merge conflict, if it lands first. Nearly there! -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org