Re: [Qemu-devel] [PATCH v2 2/4] block/qapi: always report full_backing_filename

[John Snow]

On 12/14/2015 11:36 AM, Max Reitz wrote:
> On 12.12.2015 02:25, John Snow wrote:
>> Always report full_backing_filename, even if it's the same as
>> backing_filename. In the next patch, full_backing_filename may be
>> omitted if it cannot be generated instead of allowing e.g. drive_query
>> to abort if it runs into this scenario.
>>
>> The presence or absence of the "full" field becomes useful information.
>>
>> Signed-off-by: John Snow <address@hidden>
>> ---
>>  block/qapi.c               | 7 ++++---
>>  tests/qemu-iotests/043.out | 2 ++
>>  2 files changed, 6 insertions(+), 3 deletions(-)
>>
>> diff --git a/block/qapi.c b/block/qapi.c
>> index 01569da..0e6b333 100644
>> --- a/block/qapi.c
>> +++ b/block/qapi.c
>> @@ -251,9 +251,10 @@ void bdrv_query_image_info(BlockDriverState *bs,
>>              return;
>>          }
>>  
>> -        if (strcmp(backing_filename, backing_filename2) != 0) {
>> -            info->full_backing_filename =
>> -                        g_strdup(backing_filename2);
>> +        /* Always report the full_backing_filename if present, even if it's 
>> the
>> +         * same as backing_filename. That they are same is useful info. */
>> +        if (backing_filename2) {
> 
> Is there a reason for this non-NULL check? Because it always is non-NULL
> right now.
> 
> Max
> 

No, I was just being convenient with re-ordering patches. It can be NULL
by the end of the set. I'll clean it if there's other work to do.

>> +            info->full_backing_filename = g_strdup(backing_filename2);
>>              info->has_full_backing_filename = true;
>>          }
>>  
>> diff --git a/tests/qemu-iotests/043.out b/tests/qemu-iotests/043.out
>> index 33f8cc3..b37d2a3 100644
>> --- a/tests/qemu-iotests/043.out
>> +++ b/tests/qemu-iotests/043.out
>> @@ -44,6 +44,7 @@ cluster_size: 65536
>>          "filename": "TEST_DIR/t.IMGFMT",
>>          "cluster-size": 65536,
>>          "format": "IMGFMT",
>> +        "full-backing-filename": "TEST_DIR/t.IMGFMT.2.base",
>>          "backing-filename": "TEST_DIR/t.IMGFMT.2.base",
>>          "dirty-flag": false
>>      },
>> @@ -52,6 +53,7 @@ cluster_size: 65536
>>          "filename": "TEST_DIR/t.IMGFMT.2.base",
>>          "cluster-size": 65536,
>>          "format": "IMGFMT",
>> +        "full-backing-filename": "TEST_DIR/t.IMGFMT.1.base",
>>          "backing-filename": "TEST_DIR/t.IMGFMT.1.base",
>>          "dirty-flag": false
>>      },
>>
> 
> 

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—js