Re: [Qemu-devel] [PATCH for-2.12 0/4] qmp dirty bitmap API

[John Snow]

On 11/13/2017 11:20 AM, Vladimir Sementsov-Ogievskiy wrote:
> Hi all.
> 
> There are three qmp commands, needed to implement external backup API.
> 
> Using these three commands, client may do all needed bitmap management by
> hand:
> 
> on backup start we need to do a transaction:
>  {disable old bitmap, create new bitmap}
> 
> on backup success:
>  drop old bitmap
> 
> on backup fail:
>  enable old bitmap
>  merge new bitmap to old bitmap
>  drop new bitmap
> 

Can you give me an example of how you expect these commands to be used,
and why they're required?

I'm a little weary about how error-prone these commands might be and the
potential for incorrect usage seems... high. Why do we require them?