Re: [Qemu-block] [Qemu-devel] [PATCH v9 03/13] block/dirty-bitmap: add _locked version of bdrv_reclaim_dirty_bitmap

[Paolo Bonzini]

On 22/01/2018 13:14, Vladimir Sementsov-Ogievskiy wrote:
>> so, accessing the bitmap needs mutex lock?
>>
>> Then what do you mean under accessing the bitmap? Any touch of
>> BdrvDirtyBitmap fields? Then "reading the list" will require bitmap
>> mutex too.
>> Or accessing the bitmap is accessing any field except
>> BdrvDirtyBitmap.list? Then in (2), what do you mean? For example
>> query-block will go through
>> the list, but it touches other fields too, so it should lock mutex.

The bitmap mutex is internal to block/dirty-bitmap.c.

> and one more question:
> 
> What about qmp transactions? Should we lock mutex during the whole
> transaction?

Transactions hold the BQL, but you don't need to lock the bitmap mutex.

Paolo