qemu/tests/qemu-iotests/197

#!/usr/bin/env bash
# group: rw quick
#
# Test case for copy-on-read into qcow2
#
# Copyright (C) 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=eblake@redhat.com

seq="$(basename $0)"
echo "QA output created by $seq"

status=1 # failure is the default!

# get standard environment, filters and checks
. ./common.rc
. ./common.filter

TEST_WRAP="$TEST_DIR/t.wrap.qcow2"
BLKDBG_CONF="$TEST_DIR/blkdebug.conf"

# Sanity check: our use of blkdebug fails if $TEST_DIR contains spaces
# or other problems
case "$TEST_DIR" in
    *[^-_a-zA-Z0-9/]*)
        _notrun "Suspicious TEST_DIR='$TEST_DIR', cowardly refusing to run" ;;
esac

_cleanup()
{
    _cleanup_test_img
    _rm_test_img "$TEST_WRAP"
    rm -f "$BLKDBG_CONF"
}
trap "_cleanup; exit \$status" 0 1 2 3 15

# Test is supported for any backing file; but we force qcow2 for our wrapper.
_supported_fmt generic
_supported_proto generic
# LUKS support may be possible, but it complicates things.
_unsupported_fmt luks
_unsupported_imgopts "subformat=streamOptimized"

echo
echo '=== Copy-on-read ==='
echo

# Prep the images
# VPC rounds image sizes to a specific geometry, force a specific size.
if [ "$IMGFMT" = "vpc" ]; then
    IMGOPTS=$(_optstr_add "$IMGOPTS" "force_size")
fi
_make_test_img 4G
$QEMU_IO -c "write -P 55 3G 1k" "$TEST_IMG" | _filter_qemu_io
IMGPROTO=file IMGFMT=qcow2 TEST_IMG_FILE="$TEST_WRAP" \
    _make_test_img --no-opts -F "$IMGFMT" -b "$TEST_IMG" | _filter_img_create
$QEMU_IO -f qcow2 -c "write -z -u 1M 64k" "$TEST_WRAP" | _filter_qemu_io

# Ensure that a read of two clusters, but where one is already allocated,
# does not re-write the allocated cluster
cat > "$BLKDBG_CONF" <<EOF
[inject-error]
event = "cor_write"
sector = "2048"
EOF
$QEMU_IO -c "open -C \
 -o driver=blkdebug,config=$BLKDBG_CONF,image.driver=qcow2 $TEST_WRAP" \
 -c "read -P 0 1M 128k" | _filter_qemu_io

# Read the areas we want copied. A zero-length read should still be a
# no-op.  The next read is under 2G, but aligned so that rounding to
# clusters copies more than 2G of zeroes. The final read will pick up
# the non-zero data in the same cluster.  Since a 2G read may exhaust
# memory on some machines (particularly 32-bit), we skip the test if
# that fails due to memory pressure.
$QEMU_IO -f qcow2 -C -c "read 0 0" "$TEST_WRAP" | _filter_qemu_io
output=$($QEMU_IO -f qcow2 -C -c "read -P 0 1k $((2*1024*1024*1024 - 512))" \
        "$TEST_WRAP" 2>&1 | _filter_qemu_io)
case $output in
    *allocate*)
        _notrun "Insufficient memory to run test" ;;
    *) printf '%s\n' "$output" ;;
esac
$QEMU_IO -f qcow2 -C -c "read -P 0 $((3*1024*1024*1024 + 1024)) 1k" \
    "$TEST_WRAP" | _filter_qemu_io

# Copy-on-read is incompatible with read-only
$QEMU_IO -f qcow2 -C -r "$TEST_WRAP" 2>&1 | _filter_testdir

# Break the backing chain, and show that images are identical, and that
# we properly copied over explicit zeros.
$QEMU_IMG rebase -u -b "" -f qcow2 "$TEST_WRAP"
$QEMU_IO -f qcow2 -c map "$TEST_WRAP"
_check_test_img
$QEMU_IMG compare -f $IMGFMT -F qcow2 "$TEST_IMG" "$TEST_WRAP"

echo
echo '=== Partial final cluster ==='
echo

# Force compat=1.1, because writing zeroes on a v2 image without a
# backing file would just result in an unallocated cluster
# (Also, note that this is really a pure qcow2 test.)
IMGPROTO=file IMGFMT=qcow2 TEST_IMG_FILE="$TEST_WRAP" \
    _make_test_img --no-opts -o compat=1.1 1024
$QEMU_IO -f qcow2 -C -c 'read 0 1024' "$TEST_WRAP" | _filter_qemu_io
$QEMU_IO -f qcow2 -c map "$TEST_WRAP"
_check_test_img

echo
echo '=== Copy-on-read with subclusters ==='
echo

# Create base and top images 64K (1 cluster) each.  Make subclusters enabled
# for the top image
_make_test_img 64K
IMGPROTO=file IMGFMT=qcow2 TEST_IMG_FILE="$TEST_WRAP" \
    _make_test_img --no-opts -o extended_l2=true -F "$IMGFMT" -b "$TEST_IMG" \
    64K | _filter_img_create

$QEMU_IO -c "write -P 0xaa 0 64k" "$TEST_IMG" | _filter_qemu_io

# Allocate individual subclusters in the top image, and not the whole cluster
$QEMU_IO -f qcow2 -c "write -P 0xbb 28K 2K" -c "write -P 0xcc 34K 2K" "$TEST_WRAP" \
    | _filter_qemu_io

# Only 2 subclusters should be allocated in the top image at this point
$QEMU_IO -f qcow2 -c map "$TEST_WRAP"

# Actual copy-on-read operation
$QEMU_IO -f qcow2 -C -c "read -P 0xaa 30K 4K" "$TEST_WRAP" | _filter_qemu_io

# And here we should have 4 subclusters allocated right in the middle of the
# top image. Make sure the whole cluster remains unallocated
$QEMU_IO -f qcow2 -c map "$TEST_WRAP"

_check_test_img

# success, all done
echo '*** done'
status=0