Re: [Qemu-devel] [PATCH v3 2/2] qapi: Change BlockDirtyInfo to list

[Fam Zheng <famcool@gmail.com>]

On Wed, Nov 13, 2013 at 10:19 PM, Kevin Wolf <kwolf@redhat.com> wrote:
> Am 13.11.2013 um 11:29 hat Fam Zheng geschrieben:
>> We have multiple dirty bitmaps in BDS now, switch QAPI to allow query
>> it (BlockInfo.dirty_bitmaps), and also drop old BlockInfo.dirty.
>>
>> Signed-off-by: Fam Zheng <famz@redhat.com>
>
>> diff --git a/qapi-schema.json b/qapi-schema.json
>> index 81a375b..931d710 100644
>> --- a/qapi-schema.json
>> +++ b/qapi-schema.json
>> @@ -948,8 +948,8 @@
>>  # @tray_open: #optional True if the device has a tray and it is open
>>  #             (only present if removable is true)
>>  #
>> -# @dirty: #optional dirty bitmap information (only present if the dirty
>> -#         bitmap is enabled)
>> +# @dirty-bitmaps: #optional dirty bitmaps information (only present if the
>> +#                 driver has one or more dirty bitmaps)
>>  #
>>  # @io-status: #optional @BlockDeviceIoStatus. Only present if the device
>>  #             supports it and the VM is configured to stop on errors
>> @@ -963,7 +963,7 @@
>>    'data': {'device': 'str', 'type': 'str', 'removable': 'bool',
>>             'locked': 'bool', '*inserted': 'BlockDeviceInfo',
>>             '*tray_open': 'bool', '*io-status': 'BlockDeviceIoStatus',
>> -           '*dirty': 'BlockDirtyInfo' } }
>> +           '*dirty-bitmaps': ['BlockDirtyInfo'] } }
>>
>>  ##
>>  # @query-block:
>
> I believe this is of limited use; if you ever have more than one dirty
> bitmap, we're lacking information to associate it with the job it
> belongs to. One option would be to extend BlockDirtyInfo to indicate
> this, but another might be to actually extend other commands like
> query-block-jobs to return information on the dirty bitmap associated
> with a specific job.
>
> I've applied it to block-next anyway, we still have some time to
> reconsider for 1.8.
>

Another case for this may be user enabled external dirty bitmap, which
could be standalone from any block job. E.g. when we introduce a QMP
command like:

block-new-dirty-bitmap device=foo file=bar.bitmap

This could be some code in block.c, could be a block job (really
necessary?), or a block filter. I'm not sure...

Fam