From patchwork Thu Jan 30 17:12:39 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 13954759 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id B03A0C0218F for ; Thu, 30 Jan 2025 17:16:14 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tdY6b-0000kC-Op; Thu, 30 Jan 2025 12:13:30 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tdY6Q-0000fw-CR for qemu-devel@nongnu.org; Thu, 30 Jan 2025 12:13:19 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tdY6O-0003Dd-2P for qemu-devel@nongnu.org; Thu, 30 Jan 2025 12:13:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1738257195; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XQhdlUIorhc+WfYLeEcO868bG+6tcHgkeJ1XmARqtxw=; b=C2Lt9eRWC0wyiQ3fsFxHhAprXit6cT3zcGsT1hw6DBMvWyR2ak2YqJYl/UGira4mvmkL0A iJX+xOf5HSGmpzU7aFmI5rQkCLfCIaZPp/tdwiMhe8GXmxEShn7ekzjLWk00hVWKM5csc+ o7ON0cnn+mhHQZ5+6jgxdvo3E16EUmU= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-187-qNgbe4o7MOqzLwAtCeboVw-1; Thu, 30 Jan 2025 12:13:13 -0500 X-MC-Unique: qNgbe4o7MOqzLwAtCeboVw-1 X-Mimecast-MFC-AGG-ID: qNgbe4o7MOqzLwAtCeboVw Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id F331E180035F; Thu, 30 Jan 2025 17:13:12 +0000 (UTC) Received: from merkur.redhat.com (unknown [10.39.193.13]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 7B81A30001BE; Thu, 30 Jan 2025 17:13:10 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Cc: kwolf@redhat.com, hreitz@redhat.com, stefanha@redhat.com, pkrempa@redhat.com, peterx@redhat.com, farosas@suse.de, qemu-devel@nongnu.org Subject: [PATCH v2 08/15] block: Add blockdev-set-active QMP command Date: Thu, 30 Jan 2025 18:12:39 +0100 Message-ID: <20250130171240.286878-9-kwolf@redhat.com> In-Reply-To: <20250130171240.286878-1-kwolf@redhat.com> References: <20250130171240.286878-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.3, 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, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org The system emulator tries to automatically activate and inactivate block nodes at the right point during migration. However, there are still cases where it's necessary that the user can do this manually. Images are only activated on the destination VM of a migration when the VM is actually resumed. If the VM was paused, this doesn't happen automatically. The user may want to perform some operation on a block device (e.g. taking a snapshot or starting a block job) without also resuming the VM yet. This is an example where a manual command is necessary. Another example is VM migration when the image files are opened by an external qemu-storage-daemon instance on each side. In this case, the process that needs to hand over the images isn't even part of the migration and can't know when the migration completes. Management tools need a way to explicitly inactivate images on the source and activate them on the destination. This adds a new blockdev-set-active QMP command that lets the user change the status of individual nodes (this is necessary in qemu-storage-daemon because it could be serving multiple VMs and only one of them migrates at a time). For convenience, operating on all devices (like QEMU does automatically during migration) is offered as an option, too, and can be used in the context of single VM. Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake --- qapi/block-core.json | 32 ++++++++++++++++++++++++++++++ include/block/block-global-state.h | 3 +++ block.c | 21 ++++++++++++++++++++ blockdev.c | 32 ++++++++++++++++++++++++++++++ 4 files changed, 88 insertions(+) diff --git a/qapi/block-core.json b/qapi/block-core.json index 6029e54889..2ffb2efbc7 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -4945,6 +4945,38 @@ { 'command': 'blockdev-del', 'data': { 'node-name': 'str' }, 'allow-preconfig': true } +## +# @blockdev-set-active: +# +# Activate or inactive a block device. Use this to manage the handover of block +# devices on migration with qemu-storage-daemon. +# +# Activating a node automatically activates all of its child nodes first. +# Inactivating a node automatically inactivates any of its child nodes that are +# not in use by a still active node. +# +# @node-name: Name of the graph node to activate or inactivate. By default, all +# nodes are affected by the operation. +# +# @active: true if the nodes should be active when the command returns success, +# false if they should be inactive. +# +# Since: 10.0 +# +# .. qmp-example:: +# +# -> { "execute": "blockdev-set-active", +# "arguments": { +# "node-name": "node0", +# "active": false +# } +# } +# <- { "return": {} } +## +{ 'command': 'blockdev-set-active', + 'data': { '*node-name': 'str', 'active': 'bool' }, + 'allow-preconfig': true } + ## # @BlockdevCreateOptionsFile: # diff --git a/include/block/block-global-state.h b/include/block/block-global-state.h index bd7cecd1cf..22ec21117d 100644 --- a/include/block/block-global-state.h +++ b/include/block/block-global-state.h @@ -181,6 +181,9 @@ bdrv_activate(BlockDriverState *bs, Error **errp); int coroutine_fn no_co_wrapper_bdrv_rdlock bdrv_co_activate(BlockDriverState *bs, Error **errp); +int no_coroutine_fn +bdrv_inactivate(BlockDriverState *bs, Error **errp); + void bdrv_activate_all(Error **errp); int bdrv_inactivate_all(void); diff --git a/block.c b/block.c index 95bde42dda..61e131e71f 100644 --- a/block.c +++ b/block.c @@ -7048,6 +7048,27 @@ bdrv_inactivate_recurse(BlockDriverState *bs, bool top_level) return 0; } +int bdrv_inactivate(BlockDriverState *bs, Error **errp) +{ + int ret; + + GLOBAL_STATE_CODE(); + GRAPH_RDLOCK_GUARD_MAINLOOP(); + + if (bdrv_has_bds_parent(bs, true)) { + error_setg(errp, "Node has active parent node"); + return -EPERM; + } + + ret = bdrv_inactivate_recurse(bs, true); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to inactivate node"); + return ret; + } + + return 0; +} + int bdrv_inactivate_all(void) { BlockDriverState *bs = NULL; diff --git a/blockdev.c b/blockdev.c index eb2517f1dd..7e0d433712 100644 --- a/blockdev.c +++ b/blockdev.c @@ -3471,6 +3471,38 @@ void qmp_blockdev_del(const char *node_name, Error **errp) bdrv_unref(bs); } +void qmp_blockdev_set_active(const char *node_name, bool active, Error **errp) +{ + int ret; + + GLOBAL_STATE_CODE(); + GRAPH_RDLOCK_GUARD_MAINLOOP(); + + if (!node_name) { + if (active) { + bdrv_activate_all(errp); + } else { + ret = bdrv_inactivate_all(); + if (ret < 0) { + error_setg_errno(errp, -ret, "Failed to inactivate all nodes"); + } + } + } else { + BlockDriverState *bs = bdrv_find_node(node_name); + if (!bs) { + error_setg(errp, "Failed to find node with node-name='%s'", + node_name); + return; + } + + if (active) { + bdrv_activate(bs, errp); + } else { + bdrv_inactivate(bs, errp); + } + } +} + static BdrvChild * GRAPH_RDLOCK bdrv_find_child(BlockDriverState *parent_bs, const char *child_name) {