tests/qemu-iotests/154

#!/bin/bash
#
# qcow2 specific bdrv_pwrite_zeroes tests with backing files (complements 034)
#
# Copyright (C) 2016-2017 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 <http://www.gnu.org/licenses/>.
#

# creator
owner=kwolf@redhat.com

seq=`basename $0`
echo "QA output created by $seq"

here=`pwd`
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

CLUSTER_SIZE=4k
size=$((128 * 1024 * 1024))

# This test requires zero clusters, added in v3 images
_unsupported_imgopts compat=0.10

echo
echo == backing file contains zeros ==

CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
_make_test_img -b "$TEST_IMG.base"

# Make sure that the whole cluster is allocated even for partial write_zeroes
# when the backing file contains zeros

# X = non-zero data sector in backing file
# - = sector unallocated in whole backing chain
# 0 = sector touched by write_zeroes request

# 1. Tail unaligned:    00 00 -- --
# 2. Head unaligned:    -- -- 00 00
# 3. Both unaligned:    -- 00 00 --
# 4. Both, 2 clusters:  -- -- -- 00 | 00 -- -- --

$QEMU_IO -c "write -z 0 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write -z 10k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write -z 17k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write -z 27k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

echo
echo == backing file contains non-zero data before write_zeroes ==

CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
_make_test_img -b "$TEST_IMG.base"

# Single cluster; non-zero data at the cluster start
# ... | XX -- 00 -- | ...
$QEMU_IO -c "write -P 0x11 32k 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 34k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 32k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 33k 3k" "$TEST_IMG" | _filter_qemu_io

# Single cluster; non-zero data exists, but not at the cluster start
# ... | -- XX 00 -- | ...
$QEMU_IO -c "write -P 0x11 65k 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 66k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 65k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 64k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 66k 2k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

echo
echo == backing file contains non-zero data after write_zeroes ==

CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
_make_test_img -b "$TEST_IMG.base"

# Single cluster; non-zero data directly after request
# ... | -- 00 XX -- | ...
$QEMU_IO -c "write -P 0x11 34k 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 33k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 32k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 34k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 35k 1k" "$TEST_IMG" | _filter_qemu_io

# Single cluster; non-zero data exists, but not directly after request
# ... | -- 00 -- XX | ...
$QEMU_IO -c "write -P 0x11 43k 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 41k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 43k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 40k 3k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

echo
echo == write_zeroes covers non-zero data ==

CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
_make_test_img -b "$TEST_IMG.base"

# non-zero data at front of request
# Backing file: -- XX -- --
# Active layer: -- 00 00 --

$QEMU_IO -c "write -P 0x11 5k 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 5k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 4k 4k" "$TEST_IMG" | _filter_qemu_io

# non-zero data at end of request
# Backing file: -- -- XX --
# Active layer: -- 00 00 --

$QEMU_IO -c "write -P 0x11 14k 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 13k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 12k 4k" "$TEST_IMG" | _filter_qemu_io

# non-zero data matches size of request
# Backing file: -- XX XX --
# Active layer: -- 00 00 --

$QEMU_IO -c "write -P 0x11 21k 2k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 21k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 20k 4k" "$TEST_IMG" | _filter_qemu_io

# non-zero data smaller than request
# Backing file: -- -X X- --
# Active layer: -- 00 00 --

$QEMU_IO -c "write -P 0x11 30208 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 29k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 28k 4k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

echo
echo == spanning two clusters, non-zero before request ==

CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
_make_test_img -b "$TEST_IMG.base"

# Two clusters; non-zero data before request:
# 1. At cluster start:          32k: XX -- -- 00 | 00 -- -- --
# 2. Between unallocated space: 48k: -- XX -- 00 | 00 -- -- --
# 3. Directly before request:   64k: -- -- XX 00 | 00 -- -- --

$QEMU_IO -c "write -P 0x11 32k 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 35k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 32k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 33k 7k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IO -c "write -P 0x11 49k 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 51k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 48k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 49k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 50k 6k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IO -c "write -P 0x11 66k 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 67k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 64k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 66k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 67k 5k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

echo
echo == spanning two clusters, non-zero after request ==

CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
_make_test_img -b "$TEST_IMG.base"

# Two clusters; non-zero data after request:
# 1. Directly after request:    32k: -- -- -- 00 | 00 XX -- --
# 2. Between unallocated space: 48k: -- -- -- 00 | 00 -- XX --
# 3. At cluster end:            64k: -- -- -- 00 | 00 -- -- XX

$QEMU_IO -c "write -P 0x11 37k 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 35k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 32k 5k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 37k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 38k 2k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IO -c "write -P 0x11 54k 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 51k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 48k 6k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 54k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 55k 1k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IO -c "write -P 0x11 71k 1k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 67k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 64k 7k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 71k 1k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

echo
echo == spanning two clusters, partially overwriting backing file ==

CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
_make_test_img -b "$TEST_IMG.base"

# Backing file: -- -- XX XX | XX XX -- --
# Active layer: -- -- XX 00 | 00 XX -- --

$QEMU_IO -c "write -P 0x11 2k 4k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 3k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 0k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 2k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 3k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 5k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 6k 2k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

echo
echo == spanning multiple clusters, non-zero in first cluster ==

CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
_make_test_img -b "$TEST_IMG.base"

# Backing file: 64k: XX XX -- -- | -- -- -- -- | -- -- -- --
# Active layer: 64k: XX XX 00 00 | 00 00 00 00 | 00 -- -- --

$QEMU_IO -c "write -P 0x11 64k 2k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 66k 7k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 64k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 66k 10k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

echo
echo == spanning multiple clusters, non-zero in intermediate cluster ==

CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
_make_test_img -b "$TEST_IMG.base"

# Backing file: 64k: -- -- -- -- | -- XX XX -- | -- -- -- --
# Active layer: 64k: -- -- 00 00 | 00 00 00 00 | 00 -- -- --

$QEMU_IO -c "write -P 0x11 69k 2k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 66k 7k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 64k 12k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

echo
echo == spanning multiple clusters, non-zero in final cluster ==

CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
_make_test_img -b "$TEST_IMG.base"

# Backing file: 64k: -- -- -- -- | -- -- -- -- | -- -- XX XX
# Active layer: 64k: -- -- 00 00 | 00 00 00 00 | 00 -- XX XX

$QEMU_IO -c "write -P 0x11 74k 2k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 66k 7k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 64k 10k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 74k 2k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

echo
echo == spanning multiple clusters, partially overwriting backing file ==

CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $size
_make_test_img -b "$TEST_IMG.base"

# Backing file: 64k: -- XX XX XX | XX XX XX XX | XX XX XX --
# Active layer: 64k: -- XX 00 00 | 00 00 00 00 | 00 XX XX --

$QEMU_IO -c "write -P 0x11 65k 10k" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z 66k 7k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 64k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 65k 1k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 66k 7k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0x11 73k 2k" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 75k 1k" "$TEST_IMG" | _filter_qemu_io

$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

echo
echo == unaligned image tail cluster, no allocation needed ==

# With no backing file, write to all or part of unallocated partial cluster
# will mark the cluster as zero, but does not allocate.
# Re-create the image each time to get back to unallocated clusters.

# Write at the front: sector-wise, the request is: 128m... | 00 -- -- --
_make_test_img $((size + 2048))
$QEMU_IO -c "write -z $size 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# Write at the back: sector-wise, the request is: 128m... | -- -- -- 00
_make_test_img $((size + 2048))
$QEMU_IO -c "write -z $((size + 1536)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# Write at middle: sector-wise, the request is: 128m... | -- 00 00 --
_make_test_img $((size + 2048))
$QEMU_IO -c "write -z $((size + 512)) 1024" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# Write entire cluster: sector-wise, the request is: 128m... | 00 00 00 00
_make_test_img $((size + 2048))
$QEMU_IO -c "write -z $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# Repeat with backing file holding unallocated cluster.
# TODO: Note that this forces an allocation, because we aren't yet able to
# quickly detect that reads beyond EOF of the backing file are always zero
CLUSTER_SIZE=2048 TEST_IMG="$TEST_IMG.base" _make_test_img $((size + 1024))

# Write at the front: sector-wise, the request is:
# backing: 128m... | -- --
# active:  128m... | 00 -- -- --
_make_test_img -b "$TEST_IMG.base" $((size + 2048))
$QEMU_IO -c "write -z $size 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# Write at the back: sector-wise, the request is:
# backing: 128m... | -- --
# active:  128m... | -- -- -- 00
_make_test_img -b "$TEST_IMG.base" $((size + 2048))
$QEMU_IO -c "write -z $((size + 1536)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# Write at middle: sector-wise, the request is:
# backing: 128m... | -- --
# active:  128m... | -- 00 00 --
_make_test_img -b "$TEST_IMG.base" $((size + 2048))
$QEMU_IO -c "write -z $((size + 512)) 1024" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# Write entire cluster: sector-wise, the request is:
# backing: 128m... | -- --
# active:  128m... | 00 00 00 00
_make_test_img -b "$TEST_IMG.base" $((size + 2048))
$QEMU_IO -c "write -z $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# Repeat with backing file holding zero'd cluster
# TODO: Note that this forces an allocation, because we aren't yet able to
# quickly detect that reads beyond EOF of the backing file are always zero
$QEMU_IO -c "write -z $size 512" "$TEST_IMG.base" | _filter_qemu_io

# Write at the front: sector-wise, the request is:
# backing: 128m... | 00 00
# active:  128m... | 00 -- -- --
_make_test_img -b "$TEST_IMG.base" $((size + 2048))
$QEMU_IO -c "write -z $size 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# Write at the back: sector-wise, the request is:
# backing: 128m... | 00 00
# active:  128m... | -- -- -- 00
_make_test_img -b "$TEST_IMG.base" $((size + 2048))
$QEMU_IO -c "write -z $((size + 1536)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# Write at middle: sector-wise, the request is:
# backing: 128m... | 00 00
# active:  128m... | -- 00 00 --
_make_test_img -b "$TEST_IMG.base" $((size + 2048))
$QEMU_IO -c "write -z $((size + 512)) 1024" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# Write entire cluster: sector-wise, the request is:
# backing: 128m... | 00 00
# active:  128m... | 00 00 00 00
_make_test_img -b "$TEST_IMG.base" $((size + 2048))
$QEMU_IO -c "write -z $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 2048" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# A preallocated cluster maintains its allocation, whether it stays as
# data due to a partial write:
# Convert 128m... | XX XX => ... | XX 00
_make_test_img $((size + 1024))
$QEMU_IO -c "write -P 1 $((size)) 1024" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write -z $((size + 512)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 1 $((size)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 $((size + 512)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 1024" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# or because it is the entire cluster and can use the zero flag:
# Convert 128m... | XX XX => ... | 00 00
$QEMU_IO -c "write -z $((size)) 1024" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "alloc $size 1024" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 $size 1024" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

echo
echo == unaligned image tail cluster, allocation required ==

# Write beyond backing file must COW
# Backing file: 128m... | XX --
# Active layer: 128m... | -- -- 00 --
CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $((size + 1024))
_make_test_img -b "$TEST_IMG.base" $((size + 2048))
$QEMU_IO -c "write -P 1 $((size)) 512" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z $((size + 1024)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 1 $((size)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 $((size + 512)) 1536" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# Writes at boundaries of (partial) cluster must not lose mid-cluster data
# Backing file: 128m: ... | -- XX
# Active layer: 128m: ... | 00 -- -- 00
CLUSTER_SIZE=512 TEST_IMG="$TEST_IMG.base" _make_test_img $((size + 1024))
_make_test_img -b "$TEST_IMG.base" $((size + 2048))
$QEMU_IO -c "write -P 1 $((size + 512)) 512" "$TEST_IMG.base" | _filter_qemu_io
$QEMU_IO -c "write -z $((size)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 $((size)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 1 $((size + 512)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 $((size + 1024)) 1024" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "write -z $((size + 1536)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 $((size)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 1 $((size + 512)) 512" "$TEST_IMG" | _filter_qemu_io
$QEMU_IO -c "read -P 0 $((size + 1024)) 1024" "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG map --output=json "$TEST_IMG" | _filter_qemu_img_map

# success, all done
echo "*** done"
rm -f $seq.full
status=0