Re: [Qemu-devel] [PATCH v2 3/5] qemu-img: avoid excessive BlockFragInfo line length

[Kevin Wolf]

Am 06.02.2013 14:35, schrieb Eric Blake:
> On 02/06/2013 04:30 AM, Kevin Wolf wrote:
> 
>>>  
>>> -    if (result.bfi.total_clusters != 0 && result.bfi.allocated_clusters != 
>>> 0) {
>>> -        printf("%" PRId64 "/%" PRId64 "= %0.2f%% allocated, %0.2f%% 
>>> fragmented\n",
>>> -        result.bfi.allocated_clusters, result.bfi.total_clusters,
>>> -        result.bfi.allocated_clusters * 100.0 / result.bfi.total_clusters,
>>> -        result.bfi.fragmented_clusters * 100.0 / 
>>> result.bfi.allocated_clusters);
>>> +    if (bfi->total_clusters != 0 && bfi->allocated_clusters != 0) {
>>> +        printf("%" PRId64 "/%" PRId64 "= %0.2f%% allocated, "
>>
>> Can you add a space before the '=' while touching this?
> 
> Perhaps he can, but as this is user-visible output, and we don't yet
> have a way to force JSON output to get at the same information,
> arbitrarily changing the output format may break some existing user that
> is scraping the output.  It would be nice if we had access to this
> output information in a more stable format.

Are you aware of any existing user that makes use of this information?

We're going to add JSON output soon (possibly even before this series
goes in) and scraping the output was never considered right for
'qemu-img check'. Also, so far this information only exists for QED
images, which makes it rather unlikely to be relied on. I think
modifying it is okay (if it wasn't, we would even have to think twice
about adding new fields).

Kevin