Re: [Qemu-block] [PATCH v3] block: maintain persistent disabled bitmaps

[Max Reitz]

On 2018-02-02 17:18, Eric Blake wrote:
> On 02/02/2018 10:07 AM, Vladimir Sementsov-Ogievskiy wrote:
>> To maintain load/store disabled bitmap there is new approach:
>>
>>  - deprecate @autoload flag of block-dirty-bitmap-add, make it ignored
>>  - store enabled bitmaps as "auto" to qcow2
>>  - store disabled bitmaps without "auto" flag to qcow2
>>  - on qcow2 open load "auto" bitmaps as enabled and others
>>    as disabled (except in_use bitmaps)
>>
>> Also, adjust iotests 165 and 176 appropriately.
>>
>> Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
>> ---
> 
>> +++ b/qemu-doc.texi
>> @@ -2749,6 +2749,13 @@ used and it will be removed with no replacement.
>>  The ``convert -s snapshot_id_or_name'' argument is obsoleted
>>  by the ``convert -l snapshot_param'' argument instead.
>>  
>> address@hidden QEMU Machine Protocol (QMP) commands
>> +
>> address@hidden block-dirty-bitmap-add "autoload" parameter (since 2.12.0)
>> +
>> +"autoload" parameter is now ignored. All bitmaps are automatically loaded
>> +from qcow2 image.
> 
> Won't later patches be adding the ability to enable/disable bitmaps,
> which then affects whether they are autoloaded?  So we don't forget to
> revisit this text in that patch, a better wording might be:
> 
> The "autoload" parameter is ignored; all enabled persistent dirty
> bitmaps are automatically loaded from a qcow2 image, regardless of the
> initial setting requested in this parameter.
> 
> 
>> @@ -667,19 +662,6 @@ bool bdrv_has_readonly_bitmaps(BlockDriverState *bs)
>>  }
>>  
>>  /* Called with BQL taken. */
>> -void bdrv_dirty_bitmap_set_autoload(BdrvDirtyBitmap *bitmap, bool autoload)
>> -{
>> -    qemu_mutex_lock(bitmap->mutex);
>> -    bitmap->autoload = autoload;
>> -    qemu_mutex_unlock(bitmap->mutex);
>> -}
>> -
>> -bool bdrv_dirty_bitmap_get_autoload(const BdrvDirtyBitmap *bitmap)
>> -{
>> -    return bitmap->autoload;
>> -}
> 
> Will later patches be reintroducing these functions for learning which
> bitmaps are enabled/disabled?  But I'm okay with deleting them in this
> patch, even if that is more churn.

You mean bdrv_enable_dirty_bitmap(), bdrv_disable_dirty_bitmap(), and
bdrv_dirty_bitmap_enabled()? ;-)

Max

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