qemu/tests/qemu-iotests/060

#!/usr/bin/env bash
#
# Test case for image corruption (overlapping data structures) in qcow2
#
# Copyright (C) 2013 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=mreitz@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

# Sometimes the error line might be dumped before/after an event
# randomly.  Mask it out for specific test that may trigger this
# uncertainty for current test for now.
_filter_io_error()
{
    sed '/Input\/output error/d'
}

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

# This tests qcow2-specific low-level functionality
_supported_fmt qcow2
_supported_proto file
_supported_os Linux
# These tests only work for compat=1.1 images without an external
# data file with refcount_bits=16
_unsupported_imgopts 'compat=0.10' data_file \
    'refcount_bits=\([^1]\|.\([^6]\|$\)\)'

# The repair process will create a large file - so check for availability first
_require_large_file 64G

rt_offset=65536  # 0x10000 (XXX: just an assumption)
rb_offset=131072 # 0x20000 (XXX: just an assumption)
l1_offset=196608 # 0x30000 (XXX: just an assumption)
l2_offset=262144 # 0x40000 (XXX: just an assumption)
l2_offset_after_snapshot=524288 # 0x80000 (XXX: just an assumption)

OPEN_RW="open -o overlap-check=all $TEST_IMG"
# Overlap checks are done before write operations only, therefore opening an
# image read-only makes the overlap-check option irrelevant
OPEN_RO="open -r $TEST_IMG"

echo
echo "=== Testing L2 reference into L1 ==="
echo
_make_test_img 64M
# Link first L1 entry (first L2 table) onto itself
# (Note the MSb in the L1 entry is set, ensuring the refcount is one - else any
# later write will result in a COW operation, effectively ruining this attempt
# on image corruption)
poke_file "$TEST_IMG" "$l1_offset" "\x80\x00\x00\x00\x00\x03\x00\x00"
_check_test_img

# The corrupt bit should not be set anyway
$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features

# Try to write something, thereby forcing the corrupt bit to be set
$QEMU_IO -c "$OPEN_RW" -c "write -P 0x2a 0 512" | _filter_qemu_io

# The corrupt bit must now be set
$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features

# This information should be available through qemu-img info
_img_info --format-specific

# Try to open the image R/W (which should fail)
$QEMU_IO -c "$OPEN_RW" -c "read 0 512" 2>&1 | _filter_qemu_io \
                                            | _filter_testdir \
                                            | _filter_imgfmt

# Try to open it RO (which should succeed)
$QEMU_IO -c "$OPEN_RO" -c "read 0 512" | _filter_qemu_io

# We could now try to fix the image, but this would probably fail (how should an
# L2 table linked onto the L1 table be fixed?)

echo
echo "=== Testing cluster data reference into refcount block ==="
echo
_make_test_img 64M
# Allocate L2 table
truncate -s "$(($l2_offset+65536))" "$TEST_IMG"
poke_file "$TEST_IMG" "$l1_offset" "\x80\x00\x00\x00\x00\x04\x00\x00"
# Mark cluster as used
poke_file "$TEST_IMG" "$(($rb_offset+8))" "\x00\x01"
# Redirect new data cluster onto refcount block
poke_file "$TEST_IMG" "$l2_offset" "\x80\x00\x00\x00\x00\x02\x00\x00"
_check_test_img
$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
$QEMU_IO -c "$OPEN_RW" -c "write -P 0x2a 0 512" | _filter_qemu_io
$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features

# Try to fix it
_check_test_img -r all

# The corrupt bit should be cleared
$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features

# Look if it's really really fixed
$QEMU_IO -c "$OPEN_RW" -c "write -P 0x2a 0 512" | _filter_qemu_io
$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features

echo
echo "=== Testing cluster data reference into inactive L2 table ==="
echo
_make_test_img 64M
$QEMU_IO -c "$OPEN_RW" -c "write -P 1 0 512" | _filter_qemu_io
$QEMU_IMG snapshot -c foo "$TEST_IMG"
$QEMU_IO -c "$OPEN_RW" -c "write -P 2 0 512" | _filter_qemu_io
# The inactive L2 table remains at its old offset
poke_file "$TEST_IMG" "$l2_offset_after_snapshot" \
                      "\x80\x00\x00\x00\x00\x04\x00\x00"
_check_test_img
$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
$QEMU_IO -c "$OPEN_RW" -c "write -P 3 0 512" | _filter_qemu_io
$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
_check_test_img -r all
$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
$QEMU_IO -c "$OPEN_RW" -c "write -P 4 0 512" | _filter_qemu_io
$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features

# Check data
$QEMU_IO -c "$OPEN_RO" -c "read -P 4 0 512" | _filter_qemu_io
$QEMU_IMG snapshot -a foo "$TEST_IMG"
_check_test_img
$QEMU_IO -c "$OPEN_RO" -c "read -P 1 0 512" | _filter_qemu_io

echo
echo "=== Testing overlap while COW is in flight ==="
echo
BACKING_IMG=$TEST_IMG.base
TEST_IMG=$BACKING_IMG _make_test_img 1G

$QEMU_IO -c 'write 0k 64k' "$BACKING_IMG" | _filter_qemu_io

# compat=0.10 is required in order to make the following discard actually
# unallocate the sector rather than make it a zero sector - we want COW, after
# all.
_make_test_img -o 'compat=0.10' -b "$BACKING_IMG" 1G
# Write two clusters, the second one enforces creation of an L2 table after
# the first data cluster.
$QEMU_IO -c 'write 0k 64k' -c 'write 512M 64k' "$TEST_IMG" | _filter_qemu_io
# Discard the first cluster. This cluster will soon enough be reallocated and
# used for COW.
$QEMU_IO -c 'discard 0k 64k' "$TEST_IMG" | _filter_qemu_io
# Now, corrupt the image by marking the second L2 table cluster as free.
poke_file "$TEST_IMG" '131084' "\x00\x00" # 0x2000c
# Start a write operation requiring COW on the image stopping it right before
# doing the read; then, trigger the corruption prevention by writing anything to
# any unallocated cluster, leading to an attempt to overwrite the second L2
# table. Finally, resume the COW write and see it fail (but not crash).
echo "open -o file.driver=blkdebug $TEST_IMG
break cow_read 0
aio_write 0k 1k
wait_break 0
write 64k 64k
resume 0" | $QEMU_IO | _filter_qemu_io

echo
echo "=== Testing unallocated image header ==="
echo
_make_test_img 64M
# Create L1/L2
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io
poke_file "$TEST_IMG" "$rb_offset" "\x00\x00"
$QEMU_IO -c "write 64k 64k" "$TEST_IMG" | _filter_qemu_io

echo
echo "=== Testing unaligned L1 entry ==="
echo
_make_test_img 64M
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io
# This will be masked with ~(512 - 1) = ~0x1ff, so whether the lower 9 bits are
# aligned or not does not matter
poke_file "$TEST_IMG" "$l1_offset" "\x80\x00\x00\x00\x00\x04\x2a\x00"
$QEMU_IO -c "read 0 64k" "$TEST_IMG" | _filter_qemu_io

# Test how well zero cluster expansion can cope with this
_make_test_img 64M
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io
poke_file "$TEST_IMG" "$l1_offset" "\x80\x00\x00\x00\x00\x04\x2a\x00"
$QEMU_IMG amend -o compat=0.10 "$TEST_IMG"

echo
echo "=== Testing unaligned L2 entry ==="
echo
_make_test_img 64M
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io
poke_file "$TEST_IMG" "$l2_offset" "\x80\x00\x00\x00\x00\x05\x2a\x00"
$QEMU_IO -c "read 0 64k" "$TEST_IMG" | _filter_qemu_io

echo
echo "=== Testing unaligned pre-allocated zero cluster ==="
echo
_make_test_img 64M
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io
poke_file "$TEST_IMG" "$l2_offset" "\x80\x00\x00\x00\x00\x05\x2a\x01"
# zero cluster expansion
$QEMU_IMG amend -o compat=0.10 "$TEST_IMG"

echo
echo "=== Testing unaligned reftable entry ==="
echo
_make_test_img 64M
poke_file "$TEST_IMG" "$rt_offset" "\x00\x00\x00\x00\x00\x02\x2a\x00"
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io

echo
echo "=== Testing non-fatal corruption on freeing ==="
echo
_make_test_img 64M
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io
poke_file "$TEST_IMG" "$l2_offset" "\x80\x00\x00\x00\x00\x05\x2a\x00"
$QEMU_IO -c "discard 0 64k" "$TEST_IMG" | _filter_qemu_io

echo
echo "=== Testing read-only corruption report ==="
echo
_make_test_img 64M
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io
poke_file "$TEST_IMG" "$l2_offset" "\x80\x00\x00\x00\x00\x05\x2a\x00"
# Should only emit a single error message
$QEMU_IO -c "$OPEN_RO" -c "read 0 64k" -c "read 0 64k" | _filter_qemu_io

echo
echo "=== Testing non-fatal and then fatal corruption report ==="
echo
_make_test_img 64M
$QEMU_IO -c "write 0 128k" "$TEST_IMG" | _filter_qemu_io
poke_file "$TEST_IMG" "$l2_offset"        "\x80\x00\x00\x00\x00\x05\x2a\x00"
poke_file "$TEST_IMG" "$(($l2_offset+8))" "\x80\x00\x00\x00\x00\x06\x2a\x00"
# Should emit two error messages
$QEMU_IO -c "discard 0 64k" -c "read 64k 64k" "$TEST_IMG" | _filter_qemu_io

echo
echo "=== Testing empty refcount table ==="
echo
_make_test_img 64M
poke_file "$TEST_IMG" "$rt_offset"        "\x00\x00\x00\x00\x00\x00\x00\x00"
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io
# Repair the image
_check_test_img -r all

echo
echo "=== Testing empty refcount table with valid L1 and L2 tables ==="
echo
_make_test_img 64M
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io
poke_file "$TEST_IMG" "$rt_offset"        "\x00\x00\x00\x00\x00\x00\x00\x00"
# Since the first data cluster is already allocated this triggers an
# allocation with an explicit offset (using qcow2_alloc_clusters_at())
# causing a refcount block to be allocated at offset 0
$QEMU_IO -c "write 0 128k" "$TEST_IMG" | _filter_qemu_io
# Repair the image
_check_test_img -r all

echo
echo "=== Testing empty refcount block ==="
echo
_make_test_img 64M
poke_file "$TEST_IMG" "$rb_offset"        "\x00\x00\x00\x00\x00\x00\x00\x00"
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io
# Repair the image
_check_test_img -r all

echo
echo "=== Testing empty refcount block with compressed write ==="
echo
_make_test_img 64M
$QEMU_IO -c "write 64k 64k" "$TEST_IMG" | _filter_qemu_io
poke_file "$TEST_IMG" "$rb_offset"        "\x00\x00\x00\x00\x00\x00\x00\x00"
# The previous write already allocated an L2 table, so now this new
# write will try to allocate a compressed data cluster at offset 0.
$QEMU_IO -c "write -c 0k 64k" "$TEST_IMG" | _filter_qemu_io
# Repair the image
_check_test_img -r all

echo
echo "=== Testing zero refcount table size ==="
echo
_make_test_img 64M
poke_file "$TEST_IMG" "56"                "\x00\x00\x00\x00"
$QEMU_IO -c "write 0 64k" "$TEST_IMG" 2>&1 | _filter_testdir | _filter_imgfmt
# Repair the image
_check_test_img -r all

echo
echo "=== Testing incorrect refcount table offset ==="
echo
_make_test_img 64M
poke_file "$TEST_IMG" "48"                "\x00\x00\x00\x00\x00\x00\x00\x00"
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io

echo
echo "=== Testing dirty corrupt image ==="
echo

_make_test_img 64M

# Let the refblock appear unaligned
poke_file "$TEST_IMG" "$rt_offset"        "\x00\x00\x00\x00\xff\xff\x2a\x00"
# Mark the image dirty, thus forcing an automatic check when opening it
poke_file "$TEST_IMG" 72 "\x00\x00\x00\x00\x00\x00\x00\x01"
# Open the image (qemu should refuse to do so)
$QEMU_IO -c close "$TEST_IMG" 2>&1 | _filter_testdir | _filter_imgfmt

echo '--- Repairing ---'

# The actual repair should have happened (because of the dirty bit),
# but some cleanup may have failed (like freeing the old reftable)
# because the image was already marked corrupt by that point
_check_test_img -r all

echo
echo "=== Writing to an unaligned preallocated zero cluster ==="
echo

_make_test_img 64M

# Allocate the L2 table
$QEMU_IO -c "write 0 64k" -c "discard 0 64k" "$TEST_IMG" | _filter_qemu_io
# Pretend there is a preallocated zero cluster somewhere inside the
# image header
poke_file "$TEST_IMG" "$l2_offset" "\x80\x00\x00\x00\x00\x00\x2a\x01"
# Let's write to it!
$QEMU_IO -c "write 0 64k" "$TEST_IMG" | _filter_qemu_io

echo '--- Repairing ---'
_check_test_img -r all

echo
echo '=== Discarding with an unaligned refblock ==='
echo

_make_test_img 64M

$QEMU_IO -c "write 0 128k" "$TEST_IMG" | _filter_qemu_io
# Make our refblock unaligned
poke_file "$TEST_IMG" "$(($rt_offset))" "\x00\x00\x00\x00\x00\x00\x2a\x00"
# Now try to discard something that will be submitted as two requests
# (main part + tail)
$QEMU_IO -c "discard 0 65537" "$TEST_IMG"

echo '--- Repairing ---'
# Fails the first repair because the corruption prevents the check
# function from double-checking
# (Using -q for the first invocation, because otherwise the
#  double-check error message appears above the summary for some
#  reason -- so let's just hide the summary)
_check_test_img -q -r all
_check_test_img -r all

echo
echo "=== Discarding an out-of-bounds refblock ==="
echo

_make_test_img 64M

# Pretend there's a refblock really up high
poke_file "$TEST_IMG" "$(($rt_offset+8))" "\x00\xff\xff\xff\x00\x00\x00\x00"
# Let's try to shrink the qcow2 image so that the block driver tries
# to discard that refblock (and see what happens!)
$QEMU_IMG resize --shrink "$TEST_IMG" 32M

echo '--- Checking and retrying ---'
# Image should not be resized
_img_info | grep 'virtual size'
# But it should pass this check, because the "partial" resize has
# already overwritten refblocks past the end
_check_test_img -r all
# So let's try again
$QEMU_IMG resize --shrink "$TEST_IMG" 32M
_img_info | grep 'virtual size'

echo
echo "=== Discarding a non-covered in-bounds refblock ==="
echo

_make_test_img -o 'refcount_bits=1' 64M

# Pretend there's a refblock somewhere where there is no refblock to
# cover it (but the covering refblock has a valid index in the
# reftable)
# Every refblock covers 65536 * 8 * 65536 = 32 GB, so we have to point
# to 0x10_0000_0000 (64G) to point to the third refblock
poke_file "$TEST_IMG" "$(($rt_offset+8))" "\x00\x00\x00\x10\x00\x00\x00\x00"
$QEMU_IMG resize --shrink "$TEST_IMG" 32M

echo '--- Checking and retrying ---'
# Image should not be resized
_img_info | grep 'virtual size'
# But it should pass this check, because the "partial" resize has
# already overwritten refblocks past the end
_check_test_img -r all
# So let's try again
$QEMU_IMG resize --shrink "$TEST_IMG" 32M
_img_info | grep 'virtual size'

echo
echo "=== Discarding a refblock covered by an unaligned refblock ==="
echo

_make_test_img -o 'refcount_bits=1' 64M

# Same as above
poke_file "$TEST_IMG" "$(($rt_offset+8))" "\x00\x00\x00\x10\x00\x00\x00\x00"
# But now we actually "create" an unaligned third refblock
poke_file "$TEST_IMG" "$(($rt_offset+16))" "\x00\x00\x00\x00\x00\x00\x02\x00"
$QEMU_IMG resize --shrink "$TEST_IMG" 32M

echo '--- Repairing ---'
# Fails the first repair because the corruption prevents the check
# function from double-checking
# (Using -q for the first invocation, because otherwise the
#  double-check error message appears above the summary for some
#  reason -- so let's just hide the summary)
_check_test_img -q -r all
_check_test_img -r all

echo
echo "=== Testing the QEMU shutdown with a corrupted image ==="
echo
_make_test_img 64M
poke_file "$TEST_IMG" "$rt_offset"        "\x00\x00\x00\x00\x00\x00\x00\x00"
echo "{'execute': 'qmp_capabilities'}
      {'execute': 'human-monitor-command',
       'arguments': {'command-line': 'qemu-io drive \"write 0 512\"'}}
      {'execute': 'quit'}" \
    | $QEMU -qmp stdio -nographic -nodefaults \
            -drive if=none,node-name=drive,file="$TEST_IMG",driver=qcow2 \
    | _filter_qmp | _filter_qemu_io

echo
echo "=== Testing incoming inactive corrupted image ==="
echo

_make_test_img 64M
# Create an unaligned L1 entry, so qemu will signal a corruption when
# reading from the covered area
poke_file "$TEST_IMG" "$l1_offset" "\x00\x00\x00\x00\x2a\x2a\x2a\x2a"

# Inactive images are effectively read-only images, so this should be a
# non-fatal corruption (which does not modify the image)
echo "{'execute': 'qmp_capabilities'}
      {'execute': 'human-monitor-command',
       'arguments': {'command-line': 'qemu-io drive \"read 0 512\"'}}
      {'execute': 'quit'}" \
    | $QEMU -qmp stdio -nographic -nodefaults \
            -blockdev "{'node-name': 'drive',
                        'driver': 'qcow2',
                        'file': {
                            'driver': 'file',
                            'filename': '$TEST_IMG'
                        }}" \
            -incoming exec:'cat /dev/null' \
            2>&1 \
    | _filter_qmp | _filter_qemu_io | _filter_io_error

echo
# Image should not have been marked corrupt
_img_info --format-specific | grep 'corrupt:'

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