qemu/tests/qemu-iotests/112

#!/usr/bin/env bash
# group: rw
#
# Test cases for different refcount_bits values
#
# Copyright (C) 2015 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=hreitz@redhat.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

# This tests qcow2-specific low-level functionality
_supported_fmt qcow2
_supported_proto file fuse
# This test will set refcount_bits on its own which would conflict with the
# manual setting; compat will be overridden as well;
# and external data files do not work well with our refcount testing
# also, compression type is not supported with compat=0.10 used in test
_unsupported_imgopts refcount_bits 'compat=0.10' data_file compression_type

print_refcount_bits()
{
    $QEMU_IMG info "$TEST_IMG" | sed -n '/refcount bits:/ s/^ *//p'
}

echo
echo '=== refcount_bits limits ==='
echo

# Must be positive (non-zero)
_make_test_img -o "refcount_bits=0" 64M
# Must be positive (non-negative)
_make_test_img -o "refcount_bits=-1" 64M
# May not exceed 64
_make_test_img -o "refcount_bits=128" 64M
# Must be a power of two
_make_test_img -o "refcount_bits=42" 64M

# 1 is the minimum
_make_test_img -o "refcount_bits=1" 64M
print_refcount_bits

# 64 is the maximum
_make_test_img -o "refcount_bits=64" 64M
print_refcount_bits

# 16 is the default
_make_test_img 64M
print_refcount_bits

echo
echo '=== refcount_bits and compat=0.10 ==='
echo

# Should work
_make_test_img -o "compat=0.10,refcount_bits=16" 64M
print_refcount_bits

# Should not work
_make_test_img -o "compat=0.10,refcount_bits=1" 64M
_make_test_img -o "compat=0.10,refcount_bits=64" 64M


echo
echo '=== Snapshot limit on refcount_bits=1 ==='
echo

_make_test_img -o "refcount_bits=1" 64M
print_refcount_bits

$QEMU_IO -c 'write 0 512' "$TEST_IMG" | _filter_qemu_io

# Should fail for now; in the future, this might be supported by automatically
# copying all clusters with overflowing refcount
$QEMU_IMG snapshot -c foo "$TEST_IMG"

# The new L1 table could/should be leaked
_check_test_img

echo
echo '=== Snapshot limit on refcount_bits=2 ==='
echo

_make_test_img -o "refcount_bits=2" 64M
print_refcount_bits

$QEMU_IO -c 'write 0 512' "$TEST_IMG" | _filter_qemu_io

# Should succeed
$QEMU_IMG snapshot -c foo "$TEST_IMG"
$QEMU_IMG snapshot -c bar "$TEST_IMG"
# Should fail (4th reference)
$QEMU_IMG snapshot -c baz "$TEST_IMG"

# The new L1 table could/should be leaked
_check_test_img

echo
echo '=== Compressed clusters with refcount_bits=1 ==='
echo

_make_test_img -o "refcount_bits=1" 64M
print_refcount_bits

# Both should fit into a single host cluster; instead of failing to increase the
# refcount of that cluster, qemu should just allocate a new cluster and make
# this operation succeed
$QEMU_IO -c 'write -P 0 -c  0  64k' \
         -c 'write -P 1 -c 64k 64k' \
         "$TEST_IMG" | _filter_qemu_io

_check_test_img

echo
echo '=== MSb set in 64 bit refcount ==='
echo

_make_test_img -o "refcount_bits=64" 64M
print_refcount_bits

$QEMU_IO -c 'write 0 512' "$TEST_IMG" | _filter_qemu_io

# Set the MSb in the refblock entry of the data cluster
poke_file "$TEST_IMG" $((0x20028)) "\x80\x00\x00\x00\x00\x00\x00\x00"

# Clear OFLAG_COPIED in the L2 entry of the data cluster
poke_file "$TEST_IMG" $((0x40000)) "\x00\x00\x00\x00\x00\x05\x00\x00"

# Try to write to that cluster (should work, even though the MSb is set)
$QEMU_IO -c 'write 0 512' "$TEST_IMG" | _filter_qemu_io

echo
echo '=== Snapshot on maximum 64 bit refcount value ==='
echo

_make_test_img -o "refcount_bits=64" 64M
print_refcount_bits

$QEMU_IO -c 'write 0 512' "$TEST_IMG" | _filter_qemu_io

# Set the refblock entry to the maximum value possible
poke_file "$TEST_IMG" $((0x20028)) "\xff\xff\xff\xff\xff\xff\xff\xff"

# Clear OFLAG_COPIED in the L2 entry of the data cluster
poke_file "$TEST_IMG" $((0x40000)) "\x00\x00\x00\x00\x00\x05\x00\x00"

# Try a snapshot (should correctly identify the overflow; may work in the future
# by falling back to COW)
$QEMU_IMG snapshot -c foo "$TEST_IMG"

# The new L1 table could/should be leaked; and obviously the data cluster is
# leaked (refcount=UINT64_MAX reference=1)
_check_test_img

echo
echo '=== Amend from refcount_bits=16 to refcount_bits=1 ==='
echo

_make_test_img 64M
print_refcount_bits

$QEMU_IO -c 'write 16M 32M' "$TEST_IMG" | _filter_qemu_io
$QEMU_IMG amend -o refcount_bits=1 "$TEST_IMG"
_check_test_img
print_refcount_bits

echo
echo '=== Amend from refcount_bits=1 to refcount_bits=64 ==='
echo

$QEMU_IMG amend -o refcount_bits=64 "$TEST_IMG"
_check_test_img
print_refcount_bits

echo
echo '=== Amend to compat=0.10 ==='
echo

# Should not work because refcount_bits needs to be 16 for compat=0.10
$QEMU_IMG amend -o compat=0.10 "$TEST_IMG"
print_refcount_bits
# Should work
$QEMU_IMG amend -o compat=0.10,refcount_bits=16 "$TEST_IMG"
_check_test_img
print_refcount_bits

# Get back to compat=1.1 and refcount_bits=16
$QEMU_IMG amend -o compat=1.1 "$TEST_IMG"
print_refcount_bits
# Should not work
$QEMU_IMG amend -o refcount_bits=32,compat=0.10 "$TEST_IMG"
print_refcount_bits

echo
echo '=== Amend with snapshot ==='
echo

$QEMU_IMG snapshot -c foo "$TEST_IMG"
# Just to have different refcounts across the image
$QEMU_IO -c 'write 0 16M' "$TEST_IMG" | _filter_qemu_io

# Should not work (may work in the future by first decreasing all refcounts so
# they fit into the target range by copying them)
$QEMU_IMG amend -o refcount_bits=1 "$TEST_IMG"
_check_test_img
print_refcount_bits

# Should work
$QEMU_IMG amend -o refcount_bits=2 "$TEST_IMG"
_check_test_img
print_refcount_bits

echo
echo '=== Testing too many references for check ==='
echo

_make_test_img -o "refcount_bits=1" 64M
print_refcount_bits

# This cluster should be created at 0x50000
$QEMU_IO -c 'write 0 64k' "$TEST_IMG" | _filter_qemu_io
# Now make the second L2 entry (the L2 table should be at 0x40000) point to that
# cluster, so we have two references
poke_file "$TEST_IMG" $((0x40008)) "\x80\x00\x00\x00\x00\x05\x00\x00"

# This should say "please use amend"
_check_test_img -r all

# So we do that
$QEMU_IMG amend -o refcount_bits=2 "$TEST_IMG"
print_refcount_bits

# And try again
_check_test_img -r all

echo
echo '=== Multiple walks necessary during amend ==='
echo

_make_test_img -o "refcount_bits=1,cluster_size=512" 64k

# Cluster 0 is the image header, clusters 1 to 4 are used by the L1 table, a
# single L2 table, the reftable and a single refblock. This creates 58 data
# clusters (actually, the L2 table is created here, too), so in total there are
# then 63 used clusters in the image. With a refcount width of 64, one refblock
# describes 64 clusters (512 bytes / 64 bits/entry = 64 entries), so this will
# make the first refblock in the amended image have exactly one free entry.
$QEMU_IO -c "write 0 $((58 * 512))" "$TEST_IMG" | _filter_qemu_io

# Now change the refcount width; since the first new refblock will have exactly
# one free entry, that entry will be used to store its own reference. No other
# refblocks are needed, so then the new reftable will be allocated; since the
# first new refblock is completely filled up, this will require a new refblock
# which is why the refcount width changing function will need to run through
# everything one more time until the allocations are stable.
# Having more walks than usual should be visible as regressing progress (from
# 66.67 % (2/3 walks) to 50.00 % (2/4 walks)).
$QEMU_IMG amend -o refcount_bits=64 -p "$TEST_IMG" | tr '\r' '\n' \
                                                   | grep -A 1 '66.67'
print_refcount_bits

_check_test_img


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