From patchwork Fri Feb 19 15:33:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 12095651 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 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 3A843C433DB for ; Fri, 19 Feb 2021 15:36:27 +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 BD13964D73 for ; Fri, 19 Feb 2021 15:36:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BD13964D73 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]:41890 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lD7pR-0003xn-Mc for qemu-devel@archiver.kernel.org; Fri, 19 Feb 2021 10:36:25 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:45236) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lD7nW-0000jy-HU for qemu-devel@nongnu.org; Fri, 19 Feb 2021 10:34:28 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:39431) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lD7nQ-0006AB-J6 for qemu-devel@nongnu.org; Fri, 19 Feb 2021 10:34:24 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1613748859; 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=jWrH+Pder/mK6sQSG6o0NdAqsT2RDmV3RSZzGujPIgQ=; b=N0TD9uOe+Q7xVGiZDbAln6ZVPmifTw/YTSHrMuugAKk904ICCc16vJwG7/9Dnr3mWAHE86 gcrLM6Hn4N5u3Eh7Zf2445v5rdgMxnVe3NdYjcUxpZRvQc072J41OgnNqfdfK/EuT3KPh9 DZT0RpzTbuzxNQ7p6dvlOU67g7uLL7o= 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-198-99xXD8DLOJu5v18wsYRaCA-1; Fri, 19 Feb 2021 10:33:55 -0500 X-MC-Unique: 99xXD8DLOJu5v18wsYRaCA-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 D867510082F6; Fri, 19 Feb 2021 15:33:54 +0000 (UTC) Received: from localhost (ovpn-112-191.ams2.redhat.com [10.36.112.191]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7C5E26A035; Fri, 19 Feb 2021 15:33:54 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PATCH 2/3] backup-top: Refuse I/O in inactive state Date: Fri, 19 Feb 2021 16:33:47 +0100 Message-Id: <20210219153348.41861-3-mreitz@redhat.com> In-Reply-To: <20210219153348.41861-1-mreitz@redhat.com> References: <20210219153348.41861-1-mreitz@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=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=63.128.21.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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 , Vladimir Sementsov-Ogievskiy , John Snow , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" When the backup-top node transitions from active to inactive in bdrv_backup_top_drop(), the BlockCopyState is freed and the filtered child is removed, so the node effectively becomes unusable. However, noone told its I/O functions this, so they will happily continue accessing bs->backing and s->bcs. Prevent that by aborting early when s->active is false. (After the preceding patch, the node should be gone after bdrv_backup_top_drop(), so this should largely be a theoretical problem. But still, better to be safe than sorry, and also I think it just makes sense to check s->active in the I/O functions.) Signed-off-by: Max Reitz --- block/backup-top.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/block/backup-top.c b/block/backup-top.c index d1253e1aa6..589e8b651d 100644 --- a/block/backup-top.c +++ b/block/backup-top.c @@ -45,6 +45,12 @@ static coroutine_fn int backup_top_co_preadv( BlockDriverState *bs, uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags) { + BDRVBackupTopState *s = bs->opaque; + + if (!s->active) { + return -EIO; + } + return bdrv_co_preadv(bs->backing, offset, bytes, qiov, flags); } @@ -54,6 +60,10 @@ static coroutine_fn int backup_top_cbw(BlockDriverState *bs, uint64_t offset, BDRVBackupTopState *s = bs->opaque; uint64_t off, end; + if (!s->active) { + return -EIO; + } + if (flags & BDRV_REQ_WRITE_UNCHANGED) { return 0; }