From patchwork Thu Nov 23 02:08:17 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 10072243 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id C3EE060595 for ; Thu, 23 Nov 2017 02:10:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B5B4D29D2C for ; Thu, 23 Nov 2017 02:10:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AA9E529EEC; Thu, 23 Nov 2017 02:10:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 5881C29D2C for ; Thu, 23 Nov 2017 02:10:42 +0000 (UTC) Received: from localhost ([::1]:42108 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eHgyP-0004os-Fw for patchwork-qemu-devel@patchwork.kernel.org; Wed, 22 Nov 2017 21:10:41 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33443) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eHgwm-0004fb-H2 for qemu-devel@nongnu.org; Wed, 22 Nov 2017 21:09:01 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eHgwl-0001Fq-KV for qemu-devel@nongnu.org; Wed, 22 Nov 2017 21:09:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39058) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eHgwh-0001D5-31; Wed, 22 Nov 2017 21:08:55 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 39E2B5D5EB; Thu, 23 Nov 2017 02:08:54 +0000 (UTC) Received: from localhost (ovpn-204-18.brq.redhat.com [10.40.204.18]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 727A061982; Thu, 23 Nov 2017 02:08:49 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Thu, 23 Nov 2017 03:08:17 +0100 Message-Id: <20171123020832.8165-3-mreitz@redhat.com> In-Reply-To: <20171123020832.8165-1-mreitz@redhat.com> References: <20171123020832.8165-1-mreitz@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Thu, 23 Nov 2017 02:08:54 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 02/17] qcow2: No persistent dirty bitmaps for compat=0.10 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Fam Zheng , John Snow , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Persistent dirty bitmaps require a properly functioning autoclear_features field, or we cannot track when an unsupporting program might overwrite them. Therefore, we cannot support them for compat=0.10 images. Signed-off-by: Max Reitz Reviewed-by: Eric Blake --- block/qcow2-bitmap.c | 10 ++++++++++ block/qcow2.c | 14 +++++++++++--- 2 files changed, 21 insertions(+), 3 deletions(-) diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index f45e46cfbd..efa10c6663 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -1449,6 +1449,16 @@ bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs, bool found; Qcow2BitmapList *bm_list; + if (s->qcow_version < 3) { + /* Without autoclear_features, we would always have to assume + * that a program without persistent dirty bitmap support has + * accessed this qcow2 file when opening it, and would thus + * have to drop all dirty bitmaps (defeating their purpose). + */ + error_setg(errp, "Cannot store dirty bitmaps in qcow2 v2 files"); + goto fail; + } + if (check_constraints_on_bitmap(bs, name, granularity, errp) != 0) { goto fail; } diff --git a/block/qcow2.c b/block/qcow2.c index 1914a940e5..cabf93e43c 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -302,9 +302,17 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset, } if (!(s->autoclear_features & QCOW2_AUTOCLEAR_BITMAPS)) { - warn_report("a program lacking bitmap support " - "modified this file, so all bitmaps are now " - "considered inconsistent"); + if (s->qcow_version < 3) { + /* Let's be a bit more specific */ + warn_report("This qcow2 v2 image contains bitmaps, but " + "they may have been modified by a program " + "without persistent bitmap support; so now " + "they must all be considered inconsistent"); + } else { + warn_report("a program lacking bitmap support " + "modified this file, so all bitmaps are now " + "considered inconsistent"); + } error_printf("Some clusters may be leaked, " "run 'qemu-img check -r' on the image " "file to fix.");