From patchwork Wed Sep 1 15:15:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hanna Czenczek X-Patchwork-Id: 12469629 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=-13.6 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 8EA83C432BE for ; Wed, 1 Sep 2021 15:35:16 +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 42C9260231 for ; Wed, 1 Sep 2021 15:35:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 42C9260231 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]:33616 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mLSGh-0006Oj-EM for qemu-devel@archiver.kernel.org; Wed, 01 Sep 2021 11:35:15 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49894) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mLRzZ-0005a0-AD for qemu-devel@nongnu.org; Wed, 01 Sep 2021 11:17:38 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:22673) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mLRzX-0003v2-Rw for qemu-devel@nongnu.org; Wed, 01 Sep 2021 11:17:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1630509451; 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=mKztRHW663aUlIh2EJJMrzrttdTTCRai5eK7RpunmXE=; b=Ejy3i26wizJIDzsgg7rlyjf4Ofi5ue1Ghie5XBMEruoYfK9+K5L4f7APuZSVtrtGQFsZoT jk8g8Q3GSgZHtGfhDND0VLDfLYY1aIt6ly6K5ZleNc7f7ITaOXMKpEW89NoA+jHNxxK+Bi f30j9EXElMDVwegw0zBYIk9W937EREs= 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-5-eO8qske2NWuOsRbGTEwpQw-1; Wed, 01 Sep 2021 11:17:28 -0400 X-MC-Unique: eO8qske2NWuOsRbGTEwpQw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id EFC81801B3D; Wed, 1 Sep 2021 15:17:26 +0000 (UTC) Received: from localhost (unknown [10.39.193.250]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 9472D6788D; Wed, 1 Sep 2021 15:17:26 +0000 (UTC) From: Hanna Reitz To: qemu-block@nongnu.org Subject: [PULL 30/56] block/copy-before-write: relax permission requirements when no parents Date: Wed, 1 Sep 2021 17:15:53 +0200 Message-Id: <20210901151619.689075-31-hreitz@redhat.com> In-Reply-To: <20210901151619.689075-1-hreitz@redhat.com> References: <20210901151619.689075-1-hreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 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=170.10.129.124; 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=-0.392, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, 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 are going to publish copy-before-write filter. So, user should be able to create it with blockdev-add first, specifying both filtered and target children. And then do blockdev-reopen, to actually insert the filter where needed. Currently, filter unshares write permission unconditionally on source node. It's good, but it will not allow to do blockdev-add. So, let's relax restrictions when filter doesn't have any parent. Test output is modified, as now permission conflict happens only when job creates a blk parent for filter node. Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Max Reitz Message-Id: <20210824083856.17408-11-vsementsov@virtuozzo.com> Signed-off-by: Hanna Reitz --- block/copy-before-write.c | 8 +++++--- tests/qemu-iotests/283.out | 2 +- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/block/copy-before-write.c b/block/copy-before-write.c index a7996d54db..2a51cc64e4 100644 --- a/block/copy-before-write.c +++ b/block/copy-before-write.c @@ -142,10 +142,12 @@ static void cbw_child_perm(BlockDriverState *bs, BdrvChild *c, bdrv_default_perms(bs, c, role, reopen_queue, perm, shared, nperm, nshared); - if (perm & BLK_PERM_WRITE) { - *nperm = *nperm | BLK_PERM_CONSISTENT_READ; + if (!QLIST_EMPTY(&bs->parents)) { + if (perm & BLK_PERM_WRITE) { + *nperm = *nperm | BLK_PERM_CONSISTENT_READ; + } + *nshared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); } - *nshared &= ~(BLK_PERM_WRITE | BLK_PERM_RESIZE); } } diff --git a/tests/qemu-iotests/283.out b/tests/qemu-iotests/283.out index f2b7219632..5bb75952ef 100644 --- a/tests/qemu-iotests/283.out +++ b/tests/qemu-iotests/283.out @@ -5,7 +5,7 @@ {"execute": "blockdev-add", "arguments": {"driver": "blkdebug", "image": "base", "node-name": "other", "take-child-perms": ["write"]}} {"return": {}} {"execute": "blockdev-backup", "arguments": {"device": "source", "sync": "full", "target": "target"}} -{"error": {"class": "GenericError", "desc": "Cannot append copy-before-write filter: Permission conflict on node 'base': permissions 'write' are both required by node 'other' (uses node 'base' as 'image' child) and unshared by node 'source' (uses node 'base' as 'image' child)."}} +{"error": {"class": "GenericError", "desc": "Permission conflict on node 'base': permissions 'write' are both required by node 'other' (uses node 'base' as 'image' child) and unshared by node 'source' (uses node 'base' as 'image' child)."}} === copy-before-write filter should be gone after job-finalize ===