Re: [Qemu-devel] [PATCH V11 07/17] block: add image info query function bdrv_query_image_info()

[Wenchao Xia]

于 2013-4-10 23:28, Markus Armbruster 写道:
> Wenchao Xia <address@hidden> writes:
> 
>>    This patch adds function bdrv_query_image_info(), which will
>> retrieve image info in qmp object format. The implementation is
>> based on the code moved from qemu-img.c, but uses block layer
>> function to get snapshot info.
>>
>> Signed-off-by: Wenchao Xia <address@hidden>
>> ---
>>   block/qapi.c         |   41 ++++++++++++++++++++++++++++++++++-------
>>   include/block/qapi.h |    6 +++---
>>   qemu-img.c           |    8 ++------
>>   3 files changed, 39 insertions(+), 16 deletions(-)
>>
>> diff --git a/block/qapi.c b/block/qapi.c
>> index 19d4d93..176a479 100644
>> --- a/block/qapi.c
>> +++ b/block/qapi.c
>> @@ -122,18 +122,22 @@ int bdrv_query_snapshot_info_list(BlockDriverState *bs,
>>       return 0;
>>   }
>>   
>> -void bdrv_collect_image_info(BlockDriverState *bs,
>> -                             ImageInfo *info,
>> -                             const char *filename)
>> +/* return 0 on success, and @p_info will be set only on success. */
>> +int bdrv_query_image_info(BlockDriverState *bs,
>> +                          ImageInfo **p_info,
>> +                          Error **errp)
>>   {
>>       uint64_t total_sectors;
>> -    char backing_filename[1024];
>> +    const char *backing_filename;
>>       char backing_filename2[1024];
>>       BlockDriverInfo bdi;
>> +    int ret;
>> +    Error *err = NULL;
>> +    ImageInfo *info = g_new0(ImageInfo, 1);
>>   
>>       bdrv_get_geometry(bs, &total_sectors);
>>   
>> -    info->filename        = g_strdup(filename);
>> +    info->filename        = g_strdup(bs->filename);
>>       info->format          = g_strdup(bdrv_get_format_name(bs));
>>       info->virtual_size    = total_sectors * 512;
>>       info->actual_size     = bdrv_get_allocated_file_size(bs);
>> @@ -150,8 +154,8 @@ void bdrv_collect_image_info(BlockDriverState *bs,
>>           info->dirty_flag = bdi.is_dirty;
>>           info->has_dirty_flag = true;
>>       }
>> -    bdrv_get_backing_filename(bs, backing_filename, 
>> sizeof(backing_filename));
>> -    if (backing_filename[0] != '\0') {
>> +    backing_filename = bs->backing_file;
>> +    if (backing_filename && backing_filename[0] != '\0') {
> 
> backing_filename can't possibly be null here, because bs->backing_file
> is an array.
> 
  OK, will remove it.

>>           info->backing_filename = g_strdup(backing_filename);
>>           info->has_backing_filename = true;
>>           bdrv_get_full_backing_filename(bs, backing_filename2,
>> @@ -168,4 +172,27 @@ void bdrv_collect_image_info(BlockDriverState *bs,
>>               info->has_backing_filename_format = true;
>>           }
>>       }
>> +
>> +    ret = bdrv_query_snapshot_info_list(bs, &info->snapshots, false, &err);
>> +    switch (ret) {
>> +    case 0:
>> +        if (info->snapshots) {
>> +            info->has_snapshots = true;
>> +        }
>> +        break;
>> +    /* recoverable error */
>> +    case -ENOMEDIUM:
>> +        error_free(err);
>> +        break;
>> +    case -ENOTSUP:
>> +        error_free(err);
>> +        break;
> 
> Suggest
> 
>         case -ENOMEDIUM:
>         case -ENOTSUP:
>             /* no snapshots on this device */
>             error_free(err);
>             break;
> 
> for clarity.
> 
  OK.

>> +    default:
>> +        error_propagate(errp, err);
>> +        qapi_free_ImageInfo(info);
>> +        return ret;
>> +    }
>> +
>> +    *p_info = info;
>> +    return 0;
>>   }
>> diff --git a/include/block/qapi.h b/include/block/qapi.h
>> index fe66053..2c62fdf 100644
>> --- a/include/block/qapi.h
>> +++ b/include/block/qapi.h
>> @@ -32,7 +32,7 @@ int bdrv_query_snapshot_info_list(BlockDriverState *bs,
>>                                     SnapshotInfoList **p_list,
>>                                     bool vm_snapshot,
>>                                     Error **errp);
>> -void bdrv_collect_image_info(BlockDriverState *bs,
>> -                             ImageInfo *info,
>> -                             const char *filename);
>> +int bdrv_query_image_info(BlockDriverState *bs,
>> +                          ImageInfo **p_info,
>> +                          Error **errp);
>>   #endif
>> diff --git a/qemu-img.c b/qemu-img.c
>> index 261c277..1dd0a60 100644
>> --- a/qemu-img.c
>> +++ b/qemu-img.c
>> @@ -1733,12 +1733,8 @@ static ImageInfoList *collect_image_info_list(const 
>> char *filename,
>>               goto err;
>>           }
>>   
>> -        info = g_new0(ImageInfo, 1);
>> -        bdrv_collect_image_info(bs, info, filename);
>> -        if (!bdrv_query_snapshot_info_list(bs, &info->snapshots,
>> -                                           false, NULL) &&
>> -            info->snapshots) {
>> -            info->has_snapshots = true;
>> +        if (bdrv_query_image_info(bs, &info, NULL)) {
>> +            goto err;
>>           }
>>   
>>           elem = g_new0(ImageInfoList, 1);
> 


-- 
Best Regards

Wenchao Xia