From nobody Sun Oct 5 21:16:22 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1505761232005346.1582906583676; Mon, 18 Sep 2017 12:00:32 -0700 (PDT) Received: from localhost ([::1]:38354 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1du1HT-0003PE-45 for importer@patchew.org; Mon, 18 Sep 2017 15:00:31 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44068) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1du1Fe-0001yT-JJ for qemu-devel@nongnu.org; Mon, 18 Sep 2017 14:58:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1du1Fd-0006K5-La for qemu-devel@nongnu.org; Mon, 18 Sep 2017 14:58:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42374) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1du1Fb-0006Ha-G5; Mon, 18 Sep 2017 14:58:35 -0400 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 7A0DF356DA; Mon, 18 Sep 2017 18:58:34 +0000 (UTC) Received: from red.redhat.com (ovpn-124-97.rdu2.redhat.com [10.10.124.97]) by smtp.corp.redhat.com (Postfix) with ESMTP id 466935C1A3; Mon, 18 Sep 2017 18:58:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 7A0DF356DA Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx06.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=eblake@redhat.com From: Eric Blake To: qemu-devel@nongnu.org Date: Mon, 18 Sep 2017 13:58:02 -0500 Message-Id: <20170918185819.5984-4-eblake@redhat.com> In-Reply-To: <20170918185819.5984-1-eblake@redhat.com> References: <20170918185819.5984-1-eblake@redhat.com> 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 [10.5.110.30]); Mon, 18 Sep 2017 18:58:34 +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 v8 03/20] qcow2: Ensure bitmap serialization is aligned 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, vsementsov@virtuozzo.com, jsnow@redhat.com, qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" When subdividing a bitmap serialization, the code in hbitmap.c enforces that start/count parameters are aligned (except that count can end early at end-of-bitmap). We exposed this required alignment through bdrv_dirty_bitmap_serialization_align(), but forgot to actually check that we comply with it. Fortunately, qcow2 is never dividing bitmap serialization smaller than one cluster (which is a minimum of 512 bytes); so we are always compliant with the serialization alignment (which insists that we partition at least 64 bits per chunk) because we are doing at least 4k bits per chunk. Still, it's safer to add an assertion (for the unlikely case that we'd ever support a cluster smaller than 512 bytes, or if the hbitmap implementation changes what it considers to be aligned), rather than leaving bdrv_dirty_bitmap_serialization_align() without a caller. Signed-off-by: Eric Blake Reviewed-by: John Snow --- v5: no change v4: new patch --- block/qcow2-bitmap.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index e8d3bdbd6e..b3ee4c794a 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -274,10 +274,13 @@ static int free_bitmap_clusters(BlockDriverState *bs,= Qcow2BitmapTable *tb) static uint64_t sectors_covered_by_bitmap_cluster(const BDRVQcow2State *s, const BdrvDirtyBitmap *b= itmap) { - uint32_t sector_granularity =3D + uint64_t sector_granularity =3D bdrv_dirty_bitmap_granularity(bitmap) >> BDRV_SECTOR_BITS; + uint64_t sbc =3D sector_granularity * (s->cluster_size << 3); - return (uint64_t)sector_granularity * (s->cluster_size << 3); + assert(QEMU_IS_ALIGNED(sbc, + bdrv_dirty_bitmap_serialization_align(bitmap))); + return sbc; } /* load_bitmap_data --=20 2.13.5