iotests/270: Don't store data-file with json: prefix in image

We want to disable filename parsing for data files because it's too easy
to abuse in malicious image files. Make the test ready for the change by
passing the data file explicitly in command line options.

Cc: [email protected]
Signed-off-by: Kevin Wolf <[email protected]>
Reviewed-by: Eric Blake <[email protected]>
Reviewed-by: Stefan Hajnoczi <[email protected]>
Reviewed-by: Hanna Czenczek <[email protected]>
(cherry picked from commit 7e11106)
Signed-off-by: Michael Tokarev <[email protected]>

Author: kevmw

tests/qemu-iotests/270

@@ -60,8 +60,16 @@ _make_test_img -o cluster_size=2M,data_file="$TEST_IMG.orig" \
 # "write" 2G of data without using any space.
 # (qemu-img create does not like it, though, because null-co does not
 # support image creation.)
-$QEMU_IMG amend -o data_file="json:{'driver':'null-co',,'size':'4294967296'}" \
-    "$TEST_IMG"
+test_img_with_null_data="json:{
+    'driver': '$IMGFMT',
+    'file': {
+        'filename': '$TEST_IMG'
+    },
+    'data-file': {
+        'driver': 'null-co',
+        'size':'4294967296'
+    }
+}"
 
 # This gives us a range of:
 #   2^31 - 512 + 768 - 1 = 2^31 + 255 > 2^31
@@ -74,7 +82,7 @@ $QEMU_IMG amend -o data_file="json:{'driver':'null-co',,'size':'4294967296'}" \
 # on L2 boundaries, we need large L2 tables; hence the cluster size of
 # 2 MB.  (Anything from 256 kB should work, though, because then one L2
 # table covers 8 GB.)
-$QEMU_IO -c "write 768 $((2 ** 31 - 512))" "$TEST_IMG" | _filter_qemu_io
+$QEMU_IO -c "write 768 $((2 ** 31 - 512))" "$test_img_with_null_data" | _filter_qemu_io
 
 _check_test_img