iotests: Add test for data_off check

Write a pattern to the first cluster. Corrupt the data_off field and check
if the field was repaired on image opening and the pattern has not changed.

Signed-off-by: Alexander Ivanov <alexander.ivanov@virtuozzo.com>
Reviewed-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Denis V. Lunev <den@openvz.org>

tests/qemu-iotests/tests/parallels-checks

@@ -44,6 +44,7 @@ _supported_os Linux
 SIZE=$((4 * 1024 * 1024))
 IMGFMT=parallels
 CLUSTER_SIZE_OFFSET=28
+DATA_OFF_OFFSET=48
 BAT_OFFSET=64
 
 _make_test_img $SIZE
@@ -124,6 +125,20 @@ printf "content: 0x%02x\n" `peek_file_le $TEST_IMG $(($CLUSTER_SIZE)) 1`
 echo "== check second cluster on host =="
 printf "content: 0x%02x\n" `peek_file_le $TEST_IMG $(($CLUSTER_SIZE)) 1`
 
+# Clear image
+_make_test_img $SIZE
+
+echo "== TEST DATA_OFF CHECK =="
+
+echo "== write pattern to first cluster =="
+{ $QEMU_IO -c "write -P 0x55 0 $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
+echo "== spoil data_off field =="
+poke_file "$TEST_IMG" "$DATA_OFF_OFFSET" "\xff\xff\xff\xff"
+
+echo "== check first cluster =="
+{ $QEMU_IO -c "read -P 0x55 0 $CLUSTER_SIZE" "$TEST_IMG"; } 2>&1 | _filter_qemu_io | _filter_testdir
+
 # success, all done
 echo "*** done"
 rm -f $seq.full

tests/qemu-iotests/tests/parallels-checks.out

@@ -62,4 +62,14 @@ read 1048576/1048576 bytes at offset 1048576
 content: 0x11
 == check second cluster on host ==
 content: 0x11
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=4194304
+== TEST DATA_OFF CHECK ==
+== write pattern to first cluster ==
+wrote 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+== spoil data_off field ==
+== check first cluster ==
+Repairing data_off field has incorrect value
+read 1048576/1048576 bytes at offset 0
+1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
 *** done