From patchwork Wed Sep 15 17:53:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 12497107 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=-13.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 86ECBC433F5 for ; Wed, 15 Sep 2021 18:11:33 +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 1662260041 for ; Wed, 15 Sep 2021 18:11:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1662260041 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:37070 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mQZNc-00068D-8b for qemu-devel@archiver.kernel.org; Wed, 15 Sep 2021 14:11:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51968) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mQZ6f-0006UE-Mu for qemu-devel@nongnu.org; Wed, 15 Sep 2021 13:54:01 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:22260) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mQZ6e-0006tA-3h for qemu-devel@nongnu.org; Wed, 15 Sep 2021 13:54:01 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1631728439; 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=JJLyditKkv+WSfGTBJalfCfVjtKWxjAtVBFYv2pOuv0=; b=I36BH/XY8GrFHzKz27WoJ1vgONMtWED+/fqFVNxvVQdhI+KN+IazEEr7KEGbUapZSvSAFk mr7u6kZmhhxuaqvS93GMCWCRl+6FKG9nUzAHhQZaJgzcKu7oOQeHj6PDdO/c5QJ8LnXs6b Q3auXBcwaV6PUtophvZMLOVCKAHWhhI= 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-393-axuihbpCOn6TQjxSnznaKg-1; Wed, 15 Sep 2021 13:53:58 -0400 X-MC-Unique: axuihbpCOn6TQjxSnznaKg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EB2021966320; Wed, 15 Sep 2021 17:53:56 +0000 (UTC) Received: from localhost (unknown [10.39.192.101]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9498F7771A; Wed, 15 Sep 2021 17:53:56 +0000 (UTC) From: Hanna Reitz To: qemu-block@nongnu.org Subject: [PULL 17/32] block: bdrv_inactivate_recurse(): check for permissions and fix crash Date: Wed, 15 Sep 2021 19:53:03 +0200 Message-Id: <20210915175318.853225-18-hreitz@redhat.com> In-Reply-To: <20210915175318.853225-1-hreitz@redhat.com> References: <20210915175318.853225-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=hreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=216.205.24.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.39, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-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: , Cc: Kevin Wolf , Peter Maydell , Hanna Reitz , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Vladimir Sementsov-Ogievskiy We must not inactivate child when parent has write permissions on it. Calling .bdrv_inactivate() doesn't help: actually only qcow2 has this handler and it is used to flush caches, not for permission manipulations. So, let's simply check cumulative parent permissions before inactivating the node. This commit fixes a crash when we do migration during backup: prior to the commit nothing prevents all nodes inactivation at migration finish and following backup write to the target crashes on assertion "assert(!(bs->open_flags & BDRV_O_INACTIVE));" in bdrv_co_write_req_prepare(). After the commit, we rely on the fact that copy-before-write filter keeps write permission on target node to be able to write to it. So inactivation fails and migration fails as expected. Corresponding test now passes, so, enable it. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Hanna Reitz Message-Id: <20210911120027.8063-3-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz --- block.c | 8 ++++++++ tests/qemu-iotests/tests/migrate-during-backup | 2 +- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/block.c b/block.c index 00982edf45..5ce08a79fd 100644 --- a/block.c +++ b/block.c @@ -6326,6 +6326,7 @@ static int bdrv_inactivate_recurse(BlockDriverState *bs) { BdrvChild *child, *parent; int ret; + uint64_t cumulative_perms, cumulative_shared_perms; if (!bs->drv) { return -ENOMEDIUM; @@ -6356,6 +6357,13 @@ static int bdrv_inactivate_recurse(BlockDriverState *bs) } } + bdrv_get_cumulative_perm(bs, &cumulative_perms, + &cumulative_shared_perms); + if (cumulative_perms & (BLK_PERM_WRITE | BLK_PERM_WRITE_UNCHANGED)) { + /* Our inactive parents still need write access. Inactivation failed. */ + return -EPERM; + } + bs->open_flags |= BDRV_O_INACTIVE; /* diff --git a/tests/qemu-iotests/tests/migrate-during-backup b/tests/qemu-iotests/tests/migrate-during-backup index 1046904c5a..34103229ee 100755 --- a/tests/qemu-iotests/tests/migrate-during-backup +++ b/tests/qemu-iotests/tests/migrate-during-backup @@ -1,5 +1,5 @@ #!/usr/bin/env python3 -# group: migration disabled +# group: migration # # Copyright (c) 2021 Virtuozzo International GmbH #