iotests: Add test for the regression fixed in c8bf9a9169

Signed-off-by: Alberto Garcia <berto@igalia.com>
Suggested-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 tests/qemu-iotests/313     | 103 +++++++++++++++++++++++++++++++++++++
 tests/qemu-iotests/313.out |  29 +++++++++++
 tests/qemu-iotests/group   |   1 +
 3 files changed, 133 insertions(+)
 create mode 100755 tests/qemu-iotests/313
 create mode 100644 tests/qemu-iotests/313.out

On Wed, 2020-11-25 at 19:55 +0100, Alberto Garcia wrote:
> Signed-off-by: Alberto Garcia <berto@igalia.com>
> Suggested-by: Maxim Levitsky <mlevitsk@redhat.com>
> ---
>  tests/qemu-iotests/313     | 103 +++++++++++++++++++++++++++++++++++++
>  tests/qemu-iotests/313.out |  29 +++++++++++
>  tests/qemu-iotests/group   |   1 +
>  3 files changed, 133 insertions(+)
>  create mode 100755 tests/qemu-iotests/313
>  create mode 100644 tests/qemu-iotests/313.out
> 
> diff --git a/tests/qemu-iotests/313 b/tests/qemu-iotests/313
> new file mode 100755
> index 0000000000..0a5202ad49
> --- /dev/null
> +++ b/tests/qemu-iotests/313
> @@ -0,0 +1,103 @@
> +#!/usr/bin/env bash
> +#
> +# Test for the regression fixed in commit c8bf9a9169
> +#
> +# Copyright (C) 2020 Igalia, S.L.
> +# Author: Alberto Garcia <berto@igalia.com>
> +# Based on a test case by Maxim Levitsky <mlevitsk@redhat.com>
> +#
> +# 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 <http://www.gnu.org/licenses/>;.
> +#
> +
> +# creator
> +owner=berto@igalia.com
> +
> +seq=`basename $0`
> +echo "QA output created by $seq"
> +
> +status=1    # failure is the default!
> +
> +_cleanup()
> +{
> +    _cleanup_test_img
> +}
> +trap "_cleanup; exit \$status" 0 1 2 3 15
> +
> +# get standard environment, filters and checks
> +. ./common.rc
> +. ./common.filter
> +
> +_supported_fmt qcow2
> +_supported_proto file
> +_supported_os Linux
> +_unsupported_imgopts cluster_size refcount_bits extended_l2 compat=0.10 data_file
> +
> +# The cluster size must be at least the granularity of the mirror job (4KB)
> +# Note that larger cluster sizes will produce very large images (several GBs)
> +cluster_size=4096
> +refcount_bits=64 # Make it equal to the L2 entry size for convenience
> +options="cluster_size=${cluster_size},refcount_bits=${refcount_bits}"
> +
> +# Number of refcount entries per refcount blocks
> +ref_entries=$(( ${cluster_size} * 8 / ${refcount_bits} ))
> +
> +# Number of data clusters needed to fill a refcount block
> +# Equals ${ref_entries} minus two (one L2 table and one refcount block)
> +data_clusters_per_refblock=$(( ${ref_entries} - 2 ))
> +
> +# Number of entries in the refcount cache
> +ref_blocks=4
> +
> +# Write enough data clusters to fill the refcount cache and allocate
> +# one more refcount block.
> +# Subtract 3 clusters from the total: qcow2 header, refcount table, L1 table
> +total_data_clusters=$(( ${data_clusters_per_refblock} * ${ref_blocks} + 1 - 3 ))
> +
> +# Total size to write in bytes
> +total_size=$(( ${total_data_clusters} * ${cluster_size} ))
> +
> +echo
> +echo '### Create the image'
> +echo
> +TEST_IMG_FILE=$TEST_IMG.base _make_test_img -o $options $total_size | _filter_img_create_size
> +
> +echo
> +echo '### Write data to allocate more refcount blocks than the cache can hold'
> +echo
> +$QEMU_IO -c "write -P 1 0 $total_size" $TEST_IMG.base | _filter_qemu_io
> +
> +echo
> +echo '### Create an overlay'
> +echo
> +_make_test_img -F $IMGFMT -b $TEST_IMG.base -o $options | _filter_img_create_size
> +
> +echo
> +echo '### Fill the overlay with zeroes'
> +echo
> +$QEMU_IO -c "write -z 0 $total_size" $TEST_IMG | _filter_qemu_io
> +
> +echo
> +echo '### Commit changes to the base image'
> +echo
> +$QEMU_IMG commit $TEST_IMG
> +
> +echo
> +echo '### Check the base image'
> +echo
> +$QEMU_IMG check $TEST_IMG.base
> +
> +# success, all done
> +echo "*** done"
> +rm -f $seq.full
> +status=0
> diff --git a/tests/qemu-iotests/313.out b/tests/qemu-iotests/313.out
> new file mode 100644
> index 0000000000..adb9f7bd95
> --- /dev/null
> +++ b/tests/qemu-iotests/313.out
> @@ -0,0 +1,29 @@
> +QA output created by 313
> +
> +### Create the image
> +
> +Formatting 'TEST_DIR/t.IMGFMT.base', fmt=IMGFMT size=SIZE
> +
> +### Write data to allocate more refcount blocks than the cache can hold
> +
> +wrote 8347648/8347648 bytes at offset 0
> +7.961 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +
> +### Create an overlay
> +
> +Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=SIZE backing_file=TEST_DIR/t.IMGFMT.base backing_fmt=IMGFMT
> +
> +### Fill the overlay with zeroes
> +
> +wrote 8347648/8347648 bytes at offset 0
> +7.961 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +
> +### Commit changes to the base image
> +
> +Image committed.
> +
> +### Check the base image
> +
> +No errors were found on the image.
> +Image end offset: 8396800
> +*** done
> diff --git a/tests/qemu-iotests/group b/tests/qemu-iotests/group
> index 2960dff728..df339f1720 100644
> --- a/tests/qemu-iotests/group
> +++ b/tests/qemu-iotests/group
> @@ -316,3 +316,4 @@
>  305 rw quick
>  307 rw quick export
>  309 rw auto quick
> +313 rw auto quick


Tested this and it reproduces the bug just fine.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

Best regards,
	Maxim Levitsky