Re: [Qemu-devel] [PATCH 14/20] qcow2: Factor out count_cow_clusters

[Stefan Hajnoczi]

On Fri, Apr 20, 2012 at 9:24 AM, Kevin Wolf <address@hidden> wrote:
> Am 19.04.2012 23:18, schrieb Marcelo Tosatti:
>> On Thu, Apr 19, 2012 at 05:14:20PM -0300, Marcelo Tosatti wrote:
>>>> There is one intended change in functionality in this patch, which is
>>>> that it allocates new clusters even when it could satisfy the first part
>>>> of the request with already allocated clusters. In order to check if
>>>> there is a problem with this scenario, the following patch should revert
>>>> to the old behaviour:
>>>>
>>>> --- a/block/qcow2-cluster.c
>>>> +++ b/block/qcow2-cluster.c
>>>> @@ -847,7 +847,7 @@ again:
>>>>          keep_clusters = count_contiguous_clusters(nb_clusters,
>>>> s->cluster_size,
>>>>                                                    &l2_table[l2_index],
>>>> 0, 0);
>>>>          assert(keep_clusters <= nb_clusters);
>>>> -        nb_clusters -= keep_clusters;
>>>> +        nb_clusters = 0;
>>>>      } else {
>>>>          /* For the moment, overwrite compressed clusters one by one */
>>>>          if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
>>>>
>>>> The rest is meant to be a functionally equivalent rewrite of the old
>>>> code that was required in order to allow this change.
>>>
>>> Testing.
>>
>> Corruption gone with patch above.
>
> Okay, so something must be wrong only with the new code paths, which
> makes things a bit easier. I'll have another closer look. Stefan, can
> you re-review 250196f1 as well?

I'm taking a look.

Stefan