From patchwork Wed Feb 27 17:22:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 10832113 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 237D01390 for ; Wed, 27 Feb 2019 17:30:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 064C22E989 for ; Wed, 27 Feb 2019 17:30:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 02F0B2E99B; Wed, 27 Feb 2019 17:30:54 +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=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 96E632E96B for ; Wed, 27 Feb 2019 17:30:54 +0000 (UTC) Received: from localhost ([127.0.0.1]:48032 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gz32i-0000gV-HO for patchwork-qemu-devel@patchwork.kernel.org; Wed, 27 Feb 2019 12:30:52 -0500 Received: from eggs.gnu.org ([209.51.188.92]:51473) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gz2wT-0003f1-6n for qemu-devel@nongnu.org; Wed, 27 Feb 2019 12:24:25 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gz2wE-0003ZT-Gv for qemu-devel@nongnu.org; Wed, 27 Feb 2019 12:24:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37522) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gz2wB-00030Z-Fu; Wed, 27 Feb 2019 12:24:07 -0500 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 mx1.redhat.com (Postfix) with ESMTPS id 84F4D316BCCD; Wed, 27 Feb 2019 17:23:23 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-117-19.ams2.redhat.com [10.36.117.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id DD5DE61469; Wed, 27 Feb 2019 17:23:20 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Date: Wed, 27 Feb 2019 18:22:42 +0100 Message-Id: <20190227172256.30368-7-kwolf@redhat.com> In-Reply-To: <20190227172256.30368-1-kwolf@redhat.com> References: <20190227172256.30368-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Wed, 27 Feb 2019 17:23:23 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 06/20] qcow2: Prepare qcow2_get_cluster_type() for external data file 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: kwolf@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Signed-off-by: Kevin Wolf --- block/qcow2.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/block/qcow2.h b/block/qcow2.h index 7a34bd0c53..8fe2d55005 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -521,7 +521,15 @@ static inline QCow2ClusterType qcow2_get_cluster_type(BlockDriverState *bs, } return QCOW2_CLUSTER_ZERO_PLAIN; } else if (!(l2_entry & L2E_OFFSET_MASK)) { - return QCOW2_CLUSTER_UNALLOCATED; + /* Offset 0 generally means unallocated, but it is ambiguous with + * external data files because 0 is a valid offset there. However, all + * clusters in external data files always have refcount 1, so we can + * rely on QCOW_OFLAG_COPIED to disambiguate. */ + if (has_data_file(bs) && (l2_entry & QCOW_OFLAG_COPIED)) { + return QCOW2_CLUSTER_NORMAL; + } else { + return QCOW2_CLUSTER_UNALLOCATED; + } } else { return QCOW2_CLUSTER_NORMAL; }