From patchwork Wed Mar 10 15:59:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 12128301 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4E26CC433DB for ; Wed, 10 Mar 2021 16:10:18 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DC0F764F4C for ; Wed, 10 Mar 2021 16:10:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DC0F764F4C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42466 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lK1Pc-0004b4-KN for qemu-devel@archiver.kernel.org; Wed, 10 Mar 2021 11:10:16 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:34224) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lK1F6-0003PP-SK for qemu-devel@nongnu.org; Wed, 10 Mar 2021 10:59:24 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:38639) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lK1F4-00027U-62 for qemu-devel@nongnu.org; Wed, 10 Mar 2021 10:59:24 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615391961; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ptiI8wlesc93LTtOvL0SEzMeXIKn4dDtcj6oF1KiQS4=; b=Ld2WakUomr40j0ahJBzOe2zIiSsai3hjc1nF0DXTAxZ9dH8h1h+q/IwmfwRtqi1AvhHLh1 Sqz3NKQlX82G0IkfZh099RH5Z5DoH+nECX6rloCgd6E8vCzXB5X252hwWJJAW+5g/RxfkG +67aiE0vRXvefs+KGA97A+O/WFv1TNA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-409-WLCVOUf6N7GQmDseO1-2ww-1; Wed, 10 Mar 2021 10:59:19 -0500 X-MC-Unique: WLCVOUf6N7GQmDseO1-2ww-1 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 mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2489B1005D4E; Wed, 10 Mar 2021 15:59:18 +0000 (UTC) Received: from localhost (ovpn-115-159.ams2.redhat.com [10.36.115.159]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 8A63F5B6BF; Wed, 10 Mar 2021 15:59:17 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PATCH 4/4] iotests/108: Test new refcount rebuild algorithm Date: Wed, 10 Mar 2021 16:59:06 +0100 Message-Id: <20210310155906.147478-5-mreitz@redhat.com> In-Reply-To: <20210310155906.147478-1-mreitz@redhat.com> References: <20210310155906.147478-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mreitz@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=216.205.24.124; envelope-from=mreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -29 X-Spam_score: -3.0 X-Spam_bar: --- X-Spam_report: (-3.0 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.243, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" One clear problem with how qcow2's refcount structure rebuild algorithm used to be before "qcow2: Improve refcount structure rebuilding" was that it is prone to failure for qcow2 images on block devices: There is generally unused space after the actual image, and if that exceeds what one refblock covers, the old algorithm would invariably write the reftable past the block device's end, which cannot work. The new algorithm does not have this problem. Test it with three tests: (1) Create an image with more empty space at the end than what one refblock covers, see whether rebuilding the refcount structures results in a change in the image file length. (It should not.) (2) Leave precisely enough space somewhere at the beginning of the image for the new reftable (and the refblock for that place), see whether the new algorithm puts the reftable there. (It should.) (3) Test the original problem: Create (something like) a block device with a fixed size, then create a qcow2 image in there, write some data, and then have qemu-img check rebuild the refcount structures. Before HEAD^, the reftable would have been written past the image file end, i.e. outside of what the block device provides, which cannot work. HEAD^ should have fixed that. ("Something like a block device" means a loop device if we can use one ("sudo -n losetup" works), or a FUSE block export with growable=false otherwise.) Signed-off-by: Max Reitz --- tests/qemu-iotests/108 | 259 +++++++++++++++++++++++++++++++++++++ tests/qemu-iotests/108.out | 80 ++++++++++++ 2 files changed, 339 insertions(+) diff --git a/tests/qemu-iotests/108 b/tests/qemu-iotests/108 index 8eaef0b8bf..7b1aa08781 100755 --- a/tests/qemu-iotests/108 +++ b/tests/qemu-iotests/108 @@ -37,6 +37,7 @@ trap "_cleanup; exit \$status" 0 1 2 3 15 # get standard environment, filters and checks . ./common.rc . ./common.filter +. ./common.qemu # This tests qcow2-specific low-level functionality _supported_fmt qcow2 @@ -47,6 +48,22 @@ _supported_os Linux # files _unsupported_imgopts 'refcount_bits=\([^1]\|.\([^6]\|$\)\)' data_file +# This test either needs sudo -n losetup or FUSE exports to work +if sudo -n losetup &>/dev/null; then + loopdev=true +else + loopdev=false + + # QSD --export fuse will either yield "Parameter 'id' is missing" + # or "Invalid parameter 'fuse'", depending on whether there is + # FUSE support or not. + error=$($QSD --export fuse 2>&1) + if [[ $error = *"Invalid parameter 'fuse'" ]]; then + _notrun 'Passwordless sudo for losetup or FUSE support required, but' \ + 'neither is available' + fi +fi + echo echo '=== Repairing an image without any refcount table ===' echo @@ -138,6 +155,248 @@ _make_test_img 64M poke_file "$TEST_IMG" $((0x10008)) "\xff\xff\xff\xff\xff\xff\x00\x00" _check_test_img -r all +echo +echo '=== Check rebuilt reftable location ===' + +# In an earlier version of the refcount rebuild algorithm, the +# reftable was generally placed at the image end (unless something was +# allocated in the area covered by the refblock right before the image +# file end, then we would try to place the reftable in that refblock). +# This was later changed so the reftable would be placed in the +# earliest possible location. Test this. + +echo +echo '--- Does the image size increase? ---' +echo + +# First test: Just create some image, write some data to it, and +# resize it so there is free space at the end of the image (enough +# that it spans at least one full refblock, which for cluster_size=512 +# images, spans 128k). With the old algorithm, the reftable would +# have then been placed at the end of the image file, but with the new +# one, it will be put in that free space. +# We want to check whether the size of the image file increases due to +# rebuilding the refcount structures (it should not). + +_make_test_img -o 'cluster_size=512' 1M +# Write something +$QEMU_IO -c 'write 0 64k' "$TEST_IMG" | _filter_qemu_io + +# Add free space +file_len=$(stat -c '%s' "$TEST_IMG") +truncate -s $((file_len + 256 * 1024)) "$TEST_IMG" + +# Corrupt the image by saying the image header were not allocated +rt_offset=$(peek_file_be "$TEST_IMG" 48 8) +rb_offset=$(peek_file_be "$TEST_IMG" $rt_offset 8) +poke_file "$TEST_IMG" $rb_offset "\x00\x00" + +# Check whether rebuilding the refcount structures increases the image +# file size +file_len=$(stat -c '%s' "$TEST_IMG") +echo +# The only leaks there can be are the old refcount structures that are +# leaked during rebuilding, no need to clutter the output with them +_check_test_img -r all | grep -v '^Repairing cluster.*refcount=1 reference=0' +echo +post_repair_file_len=$(stat -c '%s' "$TEST_IMG") + +if [[ $file_len -eq $post_repair_file_len ]]; then + echo 'OK: Image size did not change' +else + echo 'ERROR: Image size differs' \ + "($file_len before, $post_repair_file_len after)" +fi + +echo +echo '--- Will the reftable occupy a hole specifically left for it? ---' +echo + +# Note: With cluster_size=512, every refblock covers 128k. +# The reftable covers 8M per reftable cluster. + +# Create an image that requires two reftable clusters (just because +# this is more interesting than a single-clustered reftable). +_make_test_img -o 'cluster_size=512' 9M +$QEMU_IO -c 'write 0 8M' "$TEST_IMG" | _filter_qemu_io + +# Writing 8M will have resized the reftable. Unfortunately, doing so +# will leave holes in the file, so we need to fill them up so we can +# be sure the whole file is allocated. Do that by writing +# consecutively smaller chunks starting from 8 MB, until the file +# length increases even with a chunk size of 512. Then we must have +# filled all holes. +ofs=$((8 * 1024 * 1024)) +block_len=$((16 * 1024)) +while [[ $block_len -ge 512 ]]; do + file_len=$(stat -c '%s' "$TEST_IMG") + while [[ $(stat -c '%s' "$TEST_IMG") -eq $file_len ]]; do + # Do not include this in the reference output, it does not + # really matter which qemu-io calls we do here exactly + $QEMU_IO -c "write $ofs $block_len" "$TEST_IMG" >/dev/null + ofs=$((ofs + block_len)) + done + block_len=$((block_len / 2)) +done + +# Fill up to 9M (do not include this in the reference output either, +# $ofs is random for all we know) +$QEMU_IO -c "write $ofs $((9 * 1024 * 1024 - ofs))" "$TEST_IMG" >/dev/null + +# Make space as follows: +# - For the first refblock: Right at the beginning of the image (this +# refblock is placed in the first place possible), +# - For the reftable somewhere soon afterwards, still near the +# beginning of the image (i.e. covered by the first refblock); the +# reftable too is placed in the first place possible, but only after +# all refblocks have been placed) +# No space is needed for the other refblocks, because no refblock is +# put before the space it covers. In this test case, we do not mind +# if they are placed at the image file's end. + +# Before we make that space, we have to find out the host offset of +# the area that belonged to the two data clusters at guest offset 4k, +# because we expect the reftable to be placed there, and we will have +# to verify that it is. + +l1_offset=$(peek_file_be "$TEST_IMG" 40 8) +l2_offset=$(peek_file_be "$TEST_IMG" $l1_offset 8) +l2_offset=$((l2_offset & 0x00fffffffffffe00)) +data_4k_offset=$(peek_file_be "$TEST_IMG" \ + $((l2_offset + 4096 / 512 * 8)) 8) +data_4k_offset=$((data_4k_offset & 0x00fffffffffffe00)) + +$QEMU_IO -c "discard 0 512" -c "discard 4k 1k" "$TEST_IMG" | _filter_qemu_io + +# Corrupt the image by saying the image header were not allocated +rt_offset=$(peek_file_be "$TEST_IMG" 48 8) +rb_offset=$(peek_file_be "$TEST_IMG" $rt_offset 8) +poke_file "$TEST_IMG" $rb_offset "\x00\x00" + +echo +# The only leaks there can be are the old refcount structures that are +# leaked during rebuilding, no need to clutter the output with them +_check_test_img -r all | grep -v '^Repairing cluster.*refcount=1 reference=0' +echo + +# Check whether the reftable was put where we expected +rt_offset=$(peek_file_be "$TEST_IMG" 48 8) +if [[ $rt_offset -eq $data_4k_offset ]]; then + echo 'OK: Reftable is where we expect it' +else + echo "ERROR: Reftable is at $rt_offset, but was expected at $data_4k_offset" +fi + +echo +echo '--- Rebuilding refcount structures on block devices ---' +echo + +# A block device cannot really grow, at least not during qemu-img +# check. As mentioned in the above cases, rebuilding the refcount +# structure may lead to new refcount structures being written after +# the end of the image, and in the past that happened even if there +# was more than sufficient space in the image. Such post-EOF writes +# will not work on block devices, so test that the new algorithm +# avoids it. + +# If we have passwordless sudo and losetup, we can use those to create +# a block device. Otherwise, we can resort to qemu's FUSE export to +# create a file that isn't growable, which effectively tests the same +# thing. + +_cleanup_test_img +truncate -s $((64 * 1024 * 1024)) "$TEST_IMG" + +if $loopdev; then + export_mp=$(sudo -n losetup --show -f "$TEST_IMG") + export_mp_driver=host_device + sudo -n chmod go+rw "$export_mp" +else + # Create non-growable FUSE export that is a bit like an empty + # block device + export_mp="$TEST_DIR/fuse-export" + export_mp_driver=file + touch "$export_mp" + + qsd=y _launch_qemu \ + --blockdev file,node-name=export-node,filename="$TEST_IMG" \ + --export fuse,id=fuse-export,node-name=export-node,mountpoint="$export_mp",writable=on,growable=off + fuse_export_handle=$QEMU_HANDLE + + # Must not appear in the reference output (to stay equal to the + # losetup branch). + _send_qemu_cmd \ + $fuse_export_handle \ + '{ "execute": "qmp_capabilities" }' \ + 'return' \ + >/dev/null +fi + +# Now create a qcow2 image on the device -- unfortunately, qemu-img +# create force-creates the file, so we have to resort to the +# blockdev-create job. +qsd=y _launch_qemu \ + --blockdev $export_mp_driver,node-name=file,filename="$export_mp" + +_send_qemu_cmd \ + $QEMU_HANDLE \ + '{ "execute": "qmp_capabilities" }' \ + 'return' + +# Small cluster size again, so the image needs multiple refblocks +_send_qemu_cmd \ + $QEMU_HANDLE \ + '{ "execute": "blockdev-create", + "arguments": { + "job-id": "create", + "options": { + "driver": "qcow2", + "file": "file", + "size": '$((64 * 1024 * 1024))', + "cluster-size": 512 + } } }' \ + '"concluded"' + +_send_qemu_cmd \ + $QEMU_HANDLE \ + '{ "execute": "job-dismiss", "arguments": { "id": "create" } }' \ + 'return' + +_send_qemu_cmd \ + $QEMU_HANDLE \ + '{ "execute": "quit" }' \ + 'return' + +wait=y _cleanup_single_qemu $QEMU_HANDLE +echo + +# Write some data +$QEMU_IO -c 'write 0 64k' "$export_mp" | _filter_qemu_io + +# Corrupt the image by saying the image header were not allocated +rt_offset=$(peek_file_be "$export_mp" 48 8) +rb_offset=$(peek_file_be "$export_mp" $rt_offset 8) +poke_file "$export_mp" $rb_offset "\x00\x00" + +echo +TEST_IMG="$export_mp" _check_test_img -r all \ + | grep -v '^Repairing cluster.*refcount=1 reference=0' + +if $loopdev; then + sudo -n losetup -d "$export_mp" +else + # Again, must not appear in the reference output (to stay equal to + # the losetup branch). + _send_qemu_cmd \ + $fuse_export_handle \ + '{ "execute": "quit" }' \ + 'return' \ + >/dev/null + + wait=y _cleanup_single_qemu $fuse_export_handle >/dev/null + rm -f "$export_mp" +fi + # success, all done echo '*** done' rm -f $seq.full diff --git a/tests/qemu-iotests/108.out b/tests/qemu-iotests/108.out index 75bab8dc84..a4c571df1a 100644 --- a/tests/qemu-iotests/108.out +++ b/tests/qemu-iotests/108.out @@ -105,6 +105,86 @@ The following inconsistencies were found and repaired: 0 leaked clusters 1 corruptions +Double checking the fixed image now... +No errors were found on the image. + +=== Check rebuilt reftable location === + +--- Does the image size increase? --- + +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 +wrote 65536/65536 bytes at offset 0 +64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) + +ERROR cluster 0 refcount=0 reference=1 +Rebuilding refcount structure +The following inconsistencies were found and repaired: + + 0 leaked clusters + 1 corruptions + +Double checking the fixed image now... +No errors were found on the image. + +OK: Image size did not change + +--- Will the reftable occupy a hole specifically left for it? --- + +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=9437184 +wrote 8388608/8388608 bytes at offset 0 +8 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +discard 512/512 bytes at offset 0 +512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) +discard 1024/1024 bytes at offset 4096 +1 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) + +ERROR cluster 0 refcount=0 reference=1 +Rebuilding refcount structure +The following inconsistencies were found and repaired: + + 0 leaked clusters + 1 corruptions + +Double checking the fixed image now... +No errors were found on the image. + +OK: Reftable is where we expect it + +--- Rebuilding refcount structures on block devices --- + +{ "execute": "qmp_capabilities" } +{"return": {}} +{ "execute": "blockdev-create", + "arguments": { + "job-id": "create", + "options": { + "driver": "IMGFMT", + "file": "file", + "size": 67108864, + "cluster-size": 512 + } } } +{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "created", "id": "create"}} +{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "running", "id": "create"}} +{"return": {}} +{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "waiting", "id": "create"}} +{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "pending", "id": "create"}} +{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "concluded", "id": "create"}} +{ "execute": "job-dismiss", "arguments": { "id": "create" } } +{"timestamp": {"seconds": TIMESTAMP, "microseconds": TIMESTAMP}, "event": "JOB_STATUS_CHANGE", "data": {"status": "null", "id": "create"}} +{"return": {}} +{ "execute": "quit" } +{"return": {}} + +wrote 65536/65536 bytes at offset 0 +64 KiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) + +ERROR cluster 0 refcount=0 reference=1 +Rebuilding refcount structure +The following inconsistencies were found and repaired: + + 0 leaked clusters + 1 corruptions + Double checking the fixed image now... No errors were found on the image. *** done