Re: [Qemu-devel] [PATCH v2 05/12] mirror: perform COW if the cluster size is bigger than the granularity

[Paolo Bonzini]

Il 18/01/2013 17:22, Paolo Bonzini ha scritto:
>> > If it does, we mark the whole cluster dirty now, but in the cow_bitmap
>> > it's still marked at present on the target. When restarting the job,
>> > wouldn't it copy only the start of the cluster next time and corrupt the
>> > rest of it?
> Yes, very good catch.

Actually, it works.  Because the whole destination cluster is marked
dirty, all of it is ultimately copied correctly.  The special handling
of COW is required for all others sources of dirty data, where the dirty
bitmap can include a subset of a destination cluster, but not in this case.

I'll include the testcase, and test the patch I attached to my previous
message.

Paolo