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

[Paolo Bonzini]

Il 26/11/2012 06:51, Dietmar Maurer ha scritto:
>> Which raises the question of how to distinguish whether it's a new request to
>> bs that must go through the filters or whether it actually comes from the 
>> last
>> filter in the chain. As you can see, we don't have a well thought out plan 
>> yet,
>> just rough ideas (otherwise it would probably be implemented already).
> 
> The question is if I should modify my backup patch (regarding block filters)?

The only solution I came up with is to add before/after hooks in the
block job.  I agree with the criticism, but I think it's general enough
and at the same time easy enough to implement.

> IMHO, the current implementation is quite simple and easy to maintain.

No, "if (bs->backup_info)" simply doesn't belong in bdrv_co_writev.

Paolo