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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MSGID_FROM_MTA_HEADER,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 8A3BEC47094 for ; Thu, 10 Jun 2021 12:07:31 +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 E7807613CA for ; Thu, 10 Jun 2021 12:07:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E7807613CA Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=virtuozzo.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:46402 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lrJT7-0005Mo-Sv for qemu-devel@archiver.kernel.org; Thu, 10 Jun 2021 08:07:29 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:39592) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lrJRu-0002BQ-Ij; Thu, 10 Jun 2021 08:06:15 -0400 Received: from mail-eopbgr80090.outbound.protection.outlook.com ([40.107.8.90]:15424 helo=EUR04-VI1-obe.outbound.protection.outlook.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lrJRs-0004Nw-RD; Thu, 10 Jun 2021 08:06:14 -0400 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=FpgtGQMOilFvtYLnZ24nzozd5CHtxBjHctmPgAXCyqLJyGpQcvzISx+OQu0yKj1dNJPHhlRDIPzsACvVxwtiAHpC2K+BJ7Aavsz3eat1PkDMckfs6SmJBe/0FAIaFZ9ucGbCvehw+GQ76aYR6KUwPkQc1Ogio3zXNVT5gbqa4LJwv6Y5tjPqtdrfqhFxcvPsR60LbmaeUhfiXFOZ48u2gmXrj2yISATVdRNYOHMbvxHvNIVsJT0QrowJLMi6Jk2xcnI9tds2Go+YWaZISR4nTj0lxGrxHo8xGufYFVfiwS5B83tdVGlr3s9AwBMD2zqo4sc/RuRFIVWQadv0vsyDJA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=+K6v85Em6NlHRpNUMJVT92lfLPbH5vPdbKcny2F2KZc=; b=obkI6C8tNFOqh1c9BCVOnkGRd9Yh1RMGMROCuozd4y0kDNiQCD/BJVhfh5CEg3oLQTmM2rTM0giA5sudilpoKyPM54nTK9N2JCD6Zzwoqh6zGCvx6wo5nIAYb/I5biYQ6WvmKJ0ksDmZmtsgn7w4gd6Pbt4JwkJhhFp0tKZ6YWtEN0mdfnZ6LrgEPZVSixaRH1CEB609ey589NR6EeEvyup9e3x2v0CtTgQJIxANdhVjZ7zNsZ9jf74tOhaSXcD9vFqtRCZEh6TPc1mLikrjiO1ipVW7SQJrK+YVQTQA8d8I3rmi2dqbFssHxlktzGdUVOBeAk0H8RQL56nwaaDvrA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=virtuozzo.com; dmarc=pass action=none header.from=virtuozzo.com; dkim=pass header.d=virtuozzo.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=virtuozzo.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=+K6v85Em6NlHRpNUMJVT92lfLPbH5vPdbKcny2F2KZc=; b=sCS6nrriSf+wpicz8iyHeXnJF/glKOTkOCnTHuiMEs8cXBGvFR4MvJ8jWg3U/MYzjjbqUpJyVMgAijTx5g7AsEdhaf9NDed2ijGcr6aWhQyfvoP6xHVtqp6Fh26DxjYQvWg/8649vGoIYIHDzu90QJFVpRebHNbeITtlGPRv0Ks= Authentication-Results: nongnu.org; dkim=none (message not signed) header.d=none;nongnu.org; dmarc=none action=none header.from=virtuozzo.com; Received: from AM7PR08MB5494.eurprd08.prod.outlook.com (2603:10a6:20b:dc::15) by AM6PR08MB4277.eurprd08.prod.outlook.com (2603:10a6:20b:bd::20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4219.20; Thu, 10 Jun 2021 12:05:58 +0000 Received: from AM7PR08MB5494.eurprd08.prod.outlook.com ([fe80::f928:f4f2:77c0:74b4]) by AM7PR08MB5494.eurprd08.prod.outlook.com ([fe80::f928:f4f2:77c0:74b4%9]) with mapi id 15.20.4195.030; Thu, 10 Jun 2021 12:05:58 +0000 From: Vladimir Sementsov-Ogievskiy To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, mreitz@redhat.com, kwolf@redhat.com, berto@igalia.com, vsementsov@virtuozzo.com Subject: [PATCH v6 5/9] block: bdrv_reopen_parse_backing(): simplify handling implicit filters Date: Thu, 10 Jun 2021 15:05:33 +0300 Message-Id: <20210610120537.196183-6-vsementsov@virtuozzo.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210610120537.196183-1-vsementsov@virtuozzo.com> References: <20210610120537.196183-1-vsementsov@virtuozzo.com> Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [185.215.60.215] X-ClientProxiedBy: HE1PR0802CA0005.eurprd08.prod.outlook.com (2603:10a6:3:bd::15) To AM7PR08MB5494.eurprd08.prod.outlook.com (2603:10a6:20b:dc::15) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from localhost.localdomain (185.215.60.215) by HE1PR0802CA0005.eurprd08.prod.outlook.com (2603:10a6:3:bd::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4219.20 via Frontend Transport; Thu, 10 Jun 2021 12:05:57 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 931ff29c-9b34-44c0-94c1-08d92c081b38 X-MS-TrafficTypeDiagnostic: AM6PR08MB4277: X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:243; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255; CTRY:; LANG:en; SCL:1; SRV:; IPV:NLI; SFV:NSPM; H:AM7PR08MB5494.eurprd08.prod.outlook.com; PTR:; CAT:NONE; SFS:(4636009)(39840400004)(346002)(366004)(376002)(396003)(136003)(956004)(6486002)(2616005)(6916009)(6666004)(186003)(478600001)(2906002)(5660300002)(38100700002)(36756003)(107886003)(8936002)(26005)(16526019)(6512007)(38350700002)(86362001)(1076003)(6506007)(66556008)(66476007)(66946007)(316002)(8676002)(52116002)(4326008)(83380400001)(69590400013); DIR:OUT; SFP:1102; X-MS-Exchange-AntiSpam-MessageData: =?us-ascii?Q?o9Oz2k2Ue9qfdOm7ThWZrd7iq2iDlN+dxqLnldDsQ03j3sQ98R3DZtp/ypWv?= =?us-ascii?Q?EI6BC2lxpCWuSptEBz41fWBPs8sDhVoR7456Knh8dmVeCvR/M8ec/QVTkiOA?= =?us-ascii?Q?3hec115t3XbdS39fWMJ+SSlYjeKnHpHto44Dq6TSdukmk8VJRxG7bfMHlkMM?= =?us-ascii?Q?Pexe2ZSMahSEnC97Yp3+ObqPH1yYD8IUIbtGeAv7qL4q1oUAZKoNgeTF8Nyt?= =?us-ascii?Q?is57M3NKm9t7GcuU6r+0ikMzLpxs3znM1VgS/0WWJsKKSm0pJjYWVDKok3m9?= =?us-ascii?Q?dL2ac3muoZ6oXyhnwbjPcHIoU8KH8ifY1EX9+wdBgTJjySx2BIW85UhuxItW?= =?us-ascii?Q?gHhLUj4SK45XWRC75VqLHBNspwNQFQfHeL2dsLVKOC7o0oINY7NmT1a3dGtq?= =?us-ascii?Q?4BNdaAp+Wr3vodFh2/33m+w3YAccV6rcryy/K7LZTXMiDy0zQsLZwt+dOYcF?= =?us-ascii?Q?l2dzhEAb32aux1pUvqjKuETDvv7uH/yexyEiUi1rRpi+qjfcJZbM9WDmudnB?= =?us-ascii?Q?NiaVooDzTaTo27mlByHvM/NlCgRQyCoOVdIM6tfskQyGyYEaDpW569XjvhFI?= =?us-ascii?Q?VHvcSwtT0/NW70454RvLxL7E5MlEbzNIFvE+9VuNQleByuxiRH3UbNuj2nWu?= =?us-ascii?Q?YX1RzHczm4IrugCyPG7GQCcyq6+MHs89GaAABSX2o0HWva0aLfty5V6aoD4b?= =?us-ascii?Q?WF/xdAA3QCU/rdneg8gXWnJO67i1ru4cNv+M9LEhTQF7HUZ70cKECKYxd6iF?= =?us-ascii?Q?mlz4VXAcIunbxoMsHsX+1vBF08HuOx6yrtQTnCRmtjA/BkkitFQZYbYSWnlM?= =?us-ascii?Q?9f/veSf3gRDQd4uVxRE5DkD6SV6Z87F5swBiLOVNi7PljtSEcZ/O3sFkQ6N7?= =?us-ascii?Q?aYSsBxEK+bu4YS1KqBHQb54gao2Mc9LnKAfA/bCvzfogMyufc6yT25L5j41t?= =?us-ascii?Q?WpCglWpLoj9pDF0yFC64Amos8XznLno3tOEnwLzMo+xHLz6PQA7LgTRrhNSX?= =?us-ascii?Q?62bpiEHeWK64YPz5Y9OXmtXD/D67qVP5FwJ/Ex1Iio4h98rBHQdrq01az0Yq?= =?us-ascii?Q?aSXDAo07d4Cs13jhX7aJE9T4NCmqDDTrX7NJHpWgyp788C1BCQSDl6QGpvDb?= =?us-ascii?Q?jy/CCaSs+kxeybnOm2uN9IH8SIxqitrDFJLN+4L2qkG8fJ+fVA0E4RIlb22R?= =?us-ascii?Q?F75ebTZPycxDq/lK+YeusHrC8grdO5dW/pd4qRg/mJP5PRIwp3p8oZvNrpzK?= =?us-ascii?Q?qIsXds5HbayPISVzIhZFBDG2it4hPA7gOBwE3VKv5sRTcxXWeYsphG3+Ms2w?= =?us-ascii?Q?Nu0PrSHlQc6UvyBabok+cMLJ?= X-OriginatorOrg: virtuozzo.com X-MS-Exchange-CrossTenant-Network-Message-Id: 931ff29c-9b34-44c0-94c1-08d92c081b38 X-MS-Exchange-CrossTenant-AuthSource: AM7PR08MB5494.eurprd08.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 10 Jun 2021 12:05:57.8983 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 0bc7f26d-0264-416e-a6fc-8352af79c58f X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: F7UWZIGFloEkz1Ag1GFUsAxJ9rbf1onxMoiZEnYP33+v8AKREoP6qBcj+9n8CJXk/WkJG0WqBwHOCndcCcZyvWc7KkzEcegXJ//sQ3RCC4A= X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM6PR08MB4277 Received-SPF: pass client-ip=40.107.8.90; envelope-from=vsementsov@virtuozzo.com; helo=EUR04-VI1-obe.outbound.protection.outlook.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MSGID_FROM_MTA_HEADER=0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_PASS=-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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The logic around finding overlay here is not obvious. Actually it does two simple things: 1. If new bs is already in backing chain, split from parent bs by several implicit filters we are done, do nothing. 2. Otherwise, don't try to replace implicit filter. Let's rewrite this in more obvious way. Signed-off-by: Vladimir Sementsov-Ogievskiy --- block.c | 53 ++++++++++++++++------------------------------------- 1 file changed, 16 insertions(+), 37 deletions(-) diff --git a/block.c b/block.c index d86e26299e..1717e5cb98 100644 --- a/block.c +++ b/block.c @@ -4237,7 +4237,7 @@ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state, Error **errp) { BlockDriverState *bs = reopen_state->bs; - BlockDriverState *overlay_bs, *below_bs, *new_backing_bs; + BlockDriverState *new_backing_bs; QObject *value; const char *str; @@ -4266,6 +4266,18 @@ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state, g_assert_not_reached(); } + if (bs->backing) { + if (bdrv_skip_implicit_filters(bs->backing->bs) == new_backing_bs) { + return 0; + } + + if (bs->backing->bs->implicit) { + error_setg(errp, "Cannot change backing link if '%s' has " + "an implicit backing file", bs->node_name); + return -EPERM; + } + } + /* * Ensure that @bs can really handle backing files, because we are * about to give it one (or swap the existing one) @@ -4283,42 +4295,9 @@ static int bdrv_reopen_parse_backing(BDRVReopenState *reopen_state, return -EINVAL; } - /* - * Find the "actual" backing file by skipping all links that point - * to an implicit node, if any (e.g. a commit filter node). - * We cannot use any of the bdrv_skip_*() functions here because - * those return the first explicit node, while we are looking for - * its overlay here. - */ - overlay_bs = bs; - for (below_bs = bdrv_filter_or_cow_bs(overlay_bs); - below_bs && below_bs->implicit; - below_bs = bdrv_filter_or_cow_bs(overlay_bs)) - { - overlay_bs = below_bs; - } - - /* If we want to replace the backing file we need some extra checks */ - if (new_backing_bs != bdrv_filter_or_cow_bs(overlay_bs)) { - int ret; - - /* Check for implicit nodes between bs and its backing file */ - if (bs != overlay_bs) { - error_setg(errp, "Cannot change backing link if '%s' has " - "an implicit backing file", bs->node_name); - return -EPERM; - } - - reopen_state->replace_backing_bs = true; - reopen_state->old_backing_bs = bs->backing ? bs->backing->bs : NULL; - ret = bdrv_set_backing_noperm(bs, new_backing_bs, set_backings_tran, - errp); - if (ret < 0) { - return ret; - } - } - - return 0; + reopen_state->replace_backing_bs = true; + reopen_state->old_backing_bs = bs->backing ? bs->backing->bs : NULL; + return bdrv_set_backing_noperm(bs, new_backing_bs, set_backings_tran, errp); } /* -- 2.29.2