tests/qemu-iotests/214

   1 #!/usr/bin/env bash
   2 #
   3 # Test qcow2 image compression
   4 #
   5 # Copyright (C) 2018 Igalia, S.L.
   6 # Author: Alberto Garcia <berto@igalia.com>
   7 #
   8 # This program is free software; you can redistribute it and/or modify
   9 # it under the terms of the GNU General Public License as published by
  10 # the Free Software Foundation; either version 2 of the License, or
  11 # (at your option) any later version.
  12 #
  13 # This program is distributed in the hope that it will be useful,
  14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 # GNU General Public License for more details.
  17 #
  18 # You should have received a copy of the GNU General Public License
  19 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 #
  21
  22 seq=$(basename "$0")
  23 echo "QA output created by $seq"
  24
  25 status=1        # failure is the default!
  26
  27 _cleanup()
  28 {
  29     _cleanup_test_img
  30 }
  31 trap "_cleanup; exit \$status" 0 1 2 3 15
  32
  33 # get standard environment, filters and checks
  34 . ./common.rc
  35 . ./common.filter
  36
  37 _supported_fmt qcow2
  38 _supported_proto file
  39 _supported_os Linux
  40
  41 # Repairing the corrupted image requires qemu-img check to store a
  42 # refcount up to 3, which requires at least two refcount bits.
  43 _unsupported_imgopts 'refcount_bits=1[^0-9]'
  44
  45
  46 echo
  47 echo "=== Corrupted size field in compressed cluster descriptor ==="
  48 echo
  49 # Create an empty image and fill half of it with compressed data.
  50 # The L2 entries of the two compressed clusters are located at
  51 # 0x800000 and 0x800008, their original values are 0x4008000000a00000
  52 # and 0x4008000000a00802 (5 sectors for compressed data each).
  53 _make_test_img 8M -o cluster_size=2M
  54 $QEMU_IO -c "write -c -P 0x11 0 2M" -c "write -c -P 0x11 2M 2M" "$TEST_IMG" \
  55          2>&1 | _filter_qemu_io | _filter_testdir
  56
  57 # Reduce size of compressed data to 4 sectors: this corrupts the image.
  58 poke_file "$TEST_IMG" $((0x800000)) "\x40\x06"
  59 $QEMU_IO -c "read  -P 0x11 0 4M" "$TEST_IMG" 2>&1 | _filter_qemu_io | _filter_testdir
  60
  61 # 'qemu-img check' however doesn't see anything wrong because it
  62 # doesn't try to decompress the data and the refcounts are consistent.
  63 # TODO: update qemu-img so this can be detected.
  64 _check_test_img
  65
  66 # Increase size of compressed data to the maximum (8192 sectors).
  67 # This makes QEMU read more data (8192 sectors instead of 5, host
  68 # addresses [0xa00000, 0xdfffff]), but the decompression algorithm
  69 # stops once we have enough to restore the uncompressed cluster, so
  70 # the rest of the data is ignored.
  71 poke_file "$TEST_IMG" $((0x800000)) "\x7f\xfe"
  72 # Do it also for the second compressed cluster (L2 entry at 0x800008).
  73 # In this case the compressed data would span 3 host clusters
  74 # (host addresses: [0xa00802, 0xe00801])
  75 poke_file "$TEST_IMG" $((0x800008)) "\x7f\xfe"
  76
  77 # Here the image is too small so we're asking QEMU to read beyond the
  78 # end of the image.
  79 $QEMU_IO -c "read  -P 0x11  0 4M" "$TEST_IMG" 2>&1 | _filter_qemu_io | _filter_testdir
  80 # But if we grow the image we won't be reading beyond its end anymore.
  81 $QEMU_IO -c "write -P 0x22 4M 4M" "$TEST_IMG" 2>&1 | _filter_qemu_io | _filter_testdir
  82 $QEMU_IO -c "read  -P 0x11  0 4M" "$TEST_IMG" 2>&1 | _filter_qemu_io | _filter_testdir
  83
  84 # The refcount data is however wrong because due to the increased size
  85 # of the compressed data it now reaches the following host clusters.
  86 # This can be repaired by qemu-img check by increasing the refcount of
  87 # those clusters.
  88 # TODO: update qemu-img to correct the compressed cluster size instead.
  89 _check_test_img -r all
  90 $QEMU_IO -c "read  -P 0x11  0 4M" "$TEST_IMG" 2>&1 | _filter_qemu_io | _filter_testdir
  91 $QEMU_IO -c "read  -P 0x22 4M 4M" "$TEST_IMG" 2>&1 | _filter_qemu_io | _filter_testdir
  92
  93 # success, all done
  94 echo '*** done'
  95 rm -f $seq.full
  96 status=0