From patchwork Tue May 14 21:42:29 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 1099752 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 453WQZ1D0vz9sDn for ; Wed, 15 May 2019 07:43:34 +1000 (AEST) Received: from localhost ([127.0.0.1]:55033 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hQfCu-0008Qu-3x for incoming@patchwork.ozlabs.org; Tue, 14 May 2019 17:43:32 -0400 Received: from eggs.gnu.org ([209.51.188.92]:49304) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hQfC6-0008Ix-6R for qemu-devel@nongnu.org; Tue, 14 May 2019 17:42:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hQfC4-0006qC-UO for qemu-devel@nongnu.org; Tue, 14 May 2019 17:42:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34428) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hQfC1-0006f7-0i; Tue, 14 May 2019 17:42:37 -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 EE42036955; Tue, 14 May 2019 21:42:35 +0000 (UTC) Received: from localhost (unknown [10.40.205.236]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7F2795C236; Tue, 14 May 2019 21:42:35 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Tue, 14 May 2019 23:42:29 +0200 Message-Id: <20190514214230.22601-2-mreitz@redhat.com> In-Reply-To: <20190514214230.22601-1-mreitz@redhat.com> References: <20190514214230.22601-1-mreitz@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 [10.5.110.30]); Tue, 14 May 2019 21:42:36 +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 1/2] block/file-posix: Unaligned O_DIRECT block-status 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 , qemu-stable@nongnu.org, qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" Currently, qemu crashes whenever someone queries the block status of an unaligned image tail of an O_DIRECT image: $ echo > foo $ qemu-img map --image-opts driver=file,filename=foo,cache.direct=on Offset Length Mapped to File qemu-img: block/io.c:2093: bdrv_co_block_status: Assertion `*pnum && QEMU_IS_ALIGNED(*pnum, align) && align > offset - aligned_offset' failed. This is because bdrv_co_block_status() checks that the result returned by the driver's implementation is aligned to the request_alignment, but file-posix can fail to do so, which is actually mentioned in a comment there: "[...] possibly including a partial sector at EOF". Fix this by rounding up those partial sectors. There are two possible alternative fixes: (1) We could refuse to open unaligned image files with O_DIRECT altogether. That sounds reasonable until you realize that qcow2 does necessarily not fill up its metadata clusters, and that nobody runs qemu-img create with O_DIRECT. Therefore, unpreallocated qcow2 files usually have an unaligned image tail. (2) bdrv_co_block_status() could ignore unaligned tails. It actually throws away everything past the EOF already, so that sounds reasonable. Unfortunately, the block layer knows file lengths only with a granularity of BDRV_SECTOR_SIZE, so bdrv_co_block_status() usually would have to guess whether its file length information is inexact or whether the driver is broken. Fixing what raw_co_block_status() returns is the safest thing to do. There seems to be no other block driver that sets request_alignment and does not make sure that it always returns aligned values. Cc: qemu-stable@nongnu.org Signed-off-by: Max Reitz Reviewed-by: Eric Blake --- block/file-posix.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/block/file-posix.c b/block/file-posix.c index e09e15bbf8..f489a5420c 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -2488,6 +2488,9 @@ static int coroutine_fn raw_co_block_status(BlockDriverState *bs, off_t data = 0, hole = 0; int ret; + assert(QEMU_IS_ALIGNED(offset, bs->bl.request_alignment) && + QEMU_IS_ALIGNED(bytes, bs->bl.request_alignment)); + ret = fd_open(bs); if (ret < 0) { return ret; @@ -2513,6 +2516,20 @@ static int coroutine_fn raw_co_block_status(BlockDriverState *bs, /* On a data extent, compute bytes to the end of the extent, * possibly including a partial sector at EOF. */ *pnum = MIN(bytes, hole - offset); + + /* + * We are not allowed to return partial sectors, though, so + * round up if necessary. + */ + if (!QEMU_IS_ALIGNED(*pnum, bs->bl.request_alignment)) { + int64_t file_length = raw_getlength(bs); + if (file_length > 0) { + /* Ignore errors, this is just a safeguard */ + assert(hole == file_length); + } + *pnum = ROUND_UP(*pnum, bs->bl.request_alignment); + } + ret = BDRV_BLOCK_DATA; } else { /* On a hole, compute bytes to the beginning of the next extent. */ From patchwork Tue May 14 21:42:30 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 1099753 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 453WSV3cl3z9sDn for ; Wed, 15 May 2019 07:45:14 +1000 (AEST) Received: from localhost ([127.0.0.1]:55072 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hQfEW-0001Lx-IR for incoming@patchwork.ozlabs.org; Tue, 14 May 2019 17:45:12 -0400 Received: from eggs.gnu.org ([209.51.188.92]:49356) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hQfCC-0008NC-0x for qemu-devel@nongnu.org; Tue, 14 May 2019 17:42:49 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hQfC9-00075S-Sr for qemu-devel@nongnu.org; Tue, 14 May 2019 17:42:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46254) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hQfC3-0006kg-8R; Tue, 14 May 2019 17:42:39 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5BDE43082129; Tue, 14 May 2019 21:42:38 +0000 (UTC) Received: from localhost (unknown [10.40.205.236]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E3CF05D6A6; Tue, 14 May 2019 21:42:37 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Tue, 14 May 2019 23:42:30 +0200 Message-Id: <20190514214230.22601-3-mreitz@redhat.com> In-Reply-To: <20190514214230.22601-1-mreitz@redhat.com> References: <20190514214230.22601-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Tue, 14 May 2019 21:42:38 +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 2/2] iotests: Test unaligned raw images with O_DIRECT 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 , qemu-stable@nongnu.org, qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" We already have 221 for accesses through the page cache, but it is better to create a new file for O_DIRECT instead of integrating those test cases into 221. This way, we can make use of _supported_cache_modes (and _default_cache_mode) so the test is automatically skipped on filesystems that do not support O_DIRECT. As part of the split, add _supported_cache_modes to 221. With that, it no longer fails when run with -c none or -c directsync. Signed-off-by: Max Reitz Reviewed-by: Eric Blake --- tests/qemu-iotests/221 | 4 ++ tests/qemu-iotests/253 | 84 ++++++++++++++++++++++++++++++++++++++ tests/qemu-iotests/253.out | 14 +++++++ tests/qemu-iotests/group | 1 + 4 files changed, 103 insertions(+) create mode 100755 tests/qemu-iotests/253 create mode 100644 tests/qemu-iotests/253.out diff --git a/tests/qemu-iotests/221 b/tests/qemu-iotests/221 index 25dd47bcfe..0e9096fec7 100755 --- a/tests/qemu-iotests/221 +++ b/tests/qemu-iotests/221 @@ -1,6 +1,7 @@ #!/usr/bin/env bash # # Test qemu-img vs. unaligned images +# (See also 253, which is the O_DIRECT version) # # Copyright (C) 2018-2019 Red Hat, Inc. # @@ -37,6 +38,9 @@ _supported_fmt raw _supported_proto file _supported_os Linux +_default_cache_mode writeback +_supported_cache_modes writeback writethrough unsafe + echo echo "=== Check mapping of unaligned raw image ===" echo diff --git a/tests/qemu-iotests/253 b/tests/qemu-iotests/253 new file mode 100755 index 0000000000..d88d5afa45 --- /dev/null +++ b/tests/qemu-iotests/253 @@ -0,0 +1,84 @@ +#!/usr/bin/env bash +# +# Test qemu-img vs. unaligned images; O_DIRECT version +# (Originates from 221) +# +# Copyright (C) 2019 Red Hat, Inc. +# +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 2 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . +# + +seq="$(basename $0)" +echo "QA output created by $seq" + +status=1 # failure is the default! + +_cleanup() +{ + _cleanup_test_img +} +trap "_cleanup; exit \$status" 0 1 2 3 15 + +# get standard environment, filters and checks +. ./common.rc +. ./common.filter + +_supported_fmt raw +_supported_proto file +_supported_os Linux + +_default_cache_mode none +_supported_cache_modes none directsync + +echo +echo "=== Check mapping of unaligned raw image ===" +echo + +# We do not know how large a physical sector is, but it is certainly +# going to be a factor of 1 MB +size=$((1 * 1024 * 1024 - 1)) + +# qemu-img create rounds size up to BDRV_SECTOR_SIZE +_make_test_img $size +$QEMU_IMG map --output=json --image-opts \ + "driver=$IMGFMT,file.driver=file,file.filename=$TEST_IMG,cache.direct=on" \ + | _filter_qemu_img_map + +# so we resize it and check again +truncate --size=$size "$TEST_IMG" +$QEMU_IMG map --output=json --image-opts \ + "driver=$IMGFMT,file.driver=file,file.filename=$TEST_IMG,cache.direct=on" \ + | _filter_qemu_img_map + +# qemu-io with O_DIRECT always writes whole physical sectors. Again, +# we do not know how large a physical sector is, so we just start +# writing from a 64 kB boundary, which should always be aligned. +offset=$((1 * 1024 * 1024 - 64 * 1024)) +$QEMU_IO -c "w $offset $((size - offset))" "$TEST_IMG" | _filter_qemu_io +$QEMU_IMG map --output=json --image-opts \ + "driver=$IMGFMT,file.driver=file,file.filename=$TEST_IMG,cache.direct=on" \ + | _filter_qemu_img_map + +# Resize it and check again -- contrary to 221, we may not get partial +# sectors here, so there should be only two areas (one zero, one +# data). +truncate --size=$size "$TEST_IMG" +$QEMU_IMG map --output=json --image-opts \ + "driver=$IMGFMT,file.driver=file,file.filename=$TEST_IMG,cache.direct=on" \ + | _filter_qemu_img_map + +# success, all done +echo '*** done' +rm -f $seq.full +status=0 diff --git a/tests/qemu-iotests/253.out b/tests/qemu-iotests/253.out new file mode 100644 index 0000000000..607c0baa0b --- /dev/null +++ b/tests/qemu-iotests/253.out @@ -0,0 +1,14 @@ +QA output created by 253 + +=== Check mapping of unaligned raw image === + +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048575 +[{ "start": 0, "length": 1048576, "depth": 0, "zero": true, "data": false, "offset": OFFSET}] +[{ "start": 0, "length": 1048576, "depth": 0, "zero": true, "data": false, "offset": OFFSET}] +wrote 65535/65535 bytes at offset 983040 +63.999 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +[{ "start": 0, "length": 983040, "depth": 0, "zero": true, "data": false, "offset": OFFSET}, +{ "start": 983040, "length": 65536, "depth": 0, "zero": false, "data": true, "offset": OFFSET}] +[{ "start": 0, "length": 983040, "depth": 0, "zero": true, "data": false, "offset": OFFSET}, +{ "start": 983040, "length": 65536, "depth": 0, "zero": false, "data": true, "offset": OFFSET}] +*** done diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group index 00e474ab0a..52b7c16e15 100644 --- a/tests/qemu-iotests/group +++ b/tests/qemu-iotests/group @@ -250,3 +250,4 @@ 248 rw auto quick 249 rw auto quick 252 rw auto backing quick +253 rw auto quick