Re: [Qemu-devel] [Qemu-block] [PATCH] vmdk: Set vmdk parent backing_format to vmdk

[Thomas Huth <thuth@redhat.com>]

On 27/03/2019 10.28, Sam Eiderman wrote:
> Thanks,
> 
> Also please notice that the mentioned commit in the commit message has it’s commit id changed to b69864e.
> 
> Sam
> 
>> On 27 Mar 2019, at 2:35, Eric Blake <eblake@redhat.com> wrote:
>>
>> On 3/26/19 2:58 PM, Sam Eiderman wrote:
>>> Commit fb2105b ("vmdk: Support version=3 in VMDK descriptor files") fixed
>>> the probe function to correctly guess vmdk descriptors with version=3.
>>
>> All patches need to cc qemu-devel in addition to their maintainers (I've
>> added that now).
>>
>>>
>>> This solves the issue where vmdk snapshot with parent vmdk descriptor
>>> containing "version=3" would be treated as raw instead vmdk.
>>>
>>> In the future case where a new vmdk version is introduced, we will again
>>> experience this issue, even if the user will provide "-f vmdk" it will
>>> only apply to the tip image and not to the underlying "misprobed" parent
>>> image.
>>>
>>> The code in vmdk.c already assumes that the backing file of vmdk must be
>>> vmdk (see vmdk_is_cid_valid which returns 0 if backing file is not
>>> vmdk).
>>>
>>> So let's make it official by supplying the backing_format as vmdk.
>>>
>>> Reviewed-by: Mark Kanda <mark.kanda@oracle.com>
>>> Reviewed-By: Liran Alon <liran.alon@oracle.com>
>>> Reviewed-by: Arbel Moshe <arbel.moshe@oracle.com>
>>> Signed-off-by: Shmuel Eiderman <shmuel.eiderman@oracle.com>
>>> ---
>>> block/vmdk.c | 2 ++
>>> 1 file changed, 2 insertions(+)
>>>
>>> diff --git a/block/vmdk.c b/block/vmdk.c
>>> index 8dec6ef767..de8cb859f8 100644
>>> --- a/block/vmdk.c
>>> +++ b/block/vmdk.c
>>> @@ -397,6 +397,8 @@ static int vmdk_parent_open(BlockDriverState *bs)
>>>         pstrcpy(bs->auto_backing_file, end_name - p_name + 1, p_name);
>>>         pstrcpy(bs->backing_file, sizeof(bs->backing_file),
>>>                 bs->auto_backing_file);
>>> +        pstrcpy(bs->backing_format, sizeof(bs->backing_format),
>>> +                "vmdk");
>>>     }

 Hi,

this patch broke the vmdk qemu-iotests:

$ cd tests/qemu-iotests/ ; ./check -vmdk 110 126 ; cd ../..
[...]
110 0s ... - output mismatch (see 110.out.bad)
--- /home/thuth/devel/qemu/tests/qemu-iotests/110.out	2019-05-02
11:27:41.000000000 +0200
+++ /home/thuth/tmp/qemu-build/tests/qemu-iotests/110.out.bad	2019-05-02
11:27:54.000000000 +0200
@@ -8,6 +8,7 @@
 file format: IMGFMT
 virtual size: 64M (67108864 bytes)
 backing file: t.IMGFMT.base (actual path: TEST_DIR/t.IMGFMT.base)
+backing file format: IMGFMT

 === Non-reconstructable filename ===

@@ -15,6 +16,7 @@
 file format: IMGFMT
 virtual size: 64M (67108864 bytes)
 backing file: t.IMGFMT.base (actual path: TEST_DIR/t.IMGFMT.base)
+backing file format: IMGFMT

 === Backing name is always relative to the backed image ===

@@ -26,4 +28,5 @@
 file format: IMGFMT
 virtual size: 64M (67108864 bytes)
 backing file: t.IMGFMT.base (cannot determine actual path)
+backing file format: IMGFMT
 *** done
126 0s ... - output mismatch (see 126.out.bad)
--- /home/thuth/devel/qemu/tests/qemu-iotests/126.out	2019-05-02
11:27:41.000000000 +0200
+++ /home/thuth/tmp/qemu-build/tests/qemu-iotests/126.out.bad	2019-05-02
11:27:55.000000000 +0200
@@ -13,6 +13,7 @@
 file format: IMGFMT
 virtual size: 64M (67108864 bytes)
 backing file: ./image:base.IMGFMT (actual path:
TEST_DIR/./image:base.IMGFMT)
+backing file format: IMGFMT

 Formatting 'base.IMGFMT', fmt=IMGFMT size=67108864
 Formatting 'file:image:top.IMGFMT', fmt=IMGFMT size=67108864
backing_file=base.IMGFMT
@@ -20,4 +21,5 @@
 file format: IMGFMT
 virtual size: 64M (67108864 bytes)
 backing file: base.IMGFMT (actual path: ./base.IMGFMT)
+backing file format: IMGFMT
 *** done
Failures: 110 126
Failed 2 of 2 tests

Could you please send a patch to fix this?

 Thanks,
  Thomas