From nobody Wed Apr 16 03:21:50 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; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 15312375237601023.3822070765713; Tue, 10 Jul 2018 08:45:23 -0700 (PDT) Received: from localhost ([::1]:48450 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fcupO-0006jM-Jo for importer@patchew.org; Tue, 10 Jul 2018 11:45:22 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44183) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fcunT-00051F-LQ for qemu-devel@nongnu.org; Tue, 10 Jul 2018 11:43:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fcunS-0001aD-K5 for qemu-devel@nongnu.org; Tue, 10 Jul 2018 11:43:23 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:47614 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fcunP-0001YB-Sq; Tue, 10 Jul 2018 11:43:19 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 70C9E8151D46; Tue, 10 Jul 2018 15:43:19 +0000 (UTC) Received: from localhost.localdomain.com (ovpn-116-156.ams2.redhat.com [10.36.116.156]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9EC082026D6B; Tue, 10 Jul 2018 15:43:18 +0000 (UTC) From: Kevin Wolf To: qemu-block@nongnu.org Date: Tue, 10 Jul 2018 17:42:43 +0200 Message-Id: <20180710154304.18304-4-kwolf@redhat.com> In-Reply-To: <20180710154304.18304-1-kwolf@redhat.com> References: <20180710154304.18304-1-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Tue, 10 Jul 2018 15:43:19 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.8]); Tue, 10 Jul 2018 15:43:19 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'kwolf@redhat.com' RCPT:'' X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 66.187.233.73 Subject: [Qemu-devel] [PULL 03/24] block: Fix copy-on-read crash with partial final cluster 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, peter.maydell@linaro.org, qemu-devel@nongnu.org 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" If the virtual disk size isn't aligned to full clusters, bdrv_co_do_copy_on_readv() may get pnum =3D=3D 0 before having the full cluster completed, which will let it run into an assertion failure: qemu-io: block/io.c:1203: bdrv_co_do_copy_on_readv: Assertion `skip_bytes <= pnum' failed. Check for EOF, assert that we read at least as much as the read request originally wanted to have (which is true at EOF because otherwise bdrv_check_byte_request() would already have returned an error) and return success early even though we couldn't copy the full cluster. Signed-off-by: Kevin Wolf --- block/io.c | 6 ++++++ tests/qemu-iotests/197 | 9 +++++++++ tests/qemu-iotests/197.out | 8 ++++++++ 3 files changed, 23 insertions(+) diff --git a/block/io.c b/block/io.c index 038449f81f..4c0831149c 100644 --- a/block/io.c +++ b/block/io.c @@ -1200,6 +1200,12 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(Bdr= vChild *child, pnum =3D MIN(cluster_bytes, max_transfer); } =20 + /* Stop at EOF if the image ends in the middle of the cluster */ + if (ret =3D=3D 0 && pnum =3D=3D 0) { + assert(progress >=3D bytes); + break; + } + assert(skip_bytes < pnum); =20 if (ret <=3D 0) { diff --git a/tests/qemu-iotests/197 b/tests/qemu-iotests/197 index 3ae4975eec..0369aa5cff 100755 --- a/tests/qemu-iotests/197 +++ b/tests/qemu-iotests/197 @@ -109,6 +109,15 @@ $QEMU_IO -f qcow2 -c map "$TEST_WRAP" _check_test_img $QEMU_IMG compare -f $IMGFMT -F qcow2 "$TEST_IMG" "$TEST_WRAP" =20 +echo +echo '=3D=3D=3D Partial final cluster =3D=3D=3D' +echo + +_make_test_img 1024 +$QEMU_IO -f $IMGFMT -C -c 'read 0 1024' "$TEST_IMG" | _filter_qemu_io +$QEMU_IO -f $IMGFMT -c map "$TEST_IMG" +_check_test_img + # success, all done echo '*** done' status=3D0 diff --git a/tests/qemu-iotests/197.out b/tests/qemu-iotests/197.out index 52b4137d7b..8febda5dea 100644 --- a/tests/qemu-iotests/197.out +++ b/tests/qemu-iotests/197.out @@ -23,4 +23,12 @@ can't open device TEST_DIR/t.wrap.qcow2: Can't use copy-= on-read on read-only dev 1023.938 MiB (0x3fff0000) bytes not allocated at offset 3 GiB (0xc0010000) No errors were found on the image. Images are identical. + +=3D=3D=3D Partial final cluster =3D=3D=3D + +Formatting 'TEST_DIR/t.IMGFMT', fmt=3DIMGFMT size=3D1024 +read 1024/1024 bytes at offset 0 +1 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +1 KiB (0x400) bytes allocated at offset 0 bytes (0x0) +No errors were found on the image. *** done --=20 2.13.6