Re: [Qemu-devel] [PATCH 1/5] RFC: Efficient VM backup for qemu (v1)

[Dietmar Maurer]

> >> Filters would be implemented as BlockDrivers, i.e. you could
> >> implement
> >> .bdrv_co_write() in a filter to intercept all writes to an image.
> >
> > I am quite unsure if that make things easier.
> 
> At least it would make for a much cleaner design compared to putting code
> for every feature you can think of into bdrv_co_do_readv/writev().

So if you want to add a filter, you simply modify bs->drv to point to the 
filter?