Hi,
On Tue, Apr 9, 2013 at 8:16 PM, Dmitry Monakhov <dmonakhov@xxxxxxxxxx> wrote:
>
> you should not block bio/requests handling, but simply deffer original
> bio. Some things like that:
>
> OUR_MAIN_ENTERING_POINT {
> if (bio->bi_rw == WRITE) {
> if (cow_required(bio))
> cow_bio = create_cow_copy(bio)
> submit_bio(cow_bio);
> }
> /* Cow is not required */
> submit_bio(bio);
> }
> This approach gives us reasonable performance ~3 times slower than disk
> throughput.
> For a reference implementation you may look at driver/dm/dm-snap or to
> Acronis snapapi module (AFAIR it is opensource)
> }
Thanks. That is what I was looking for. Got the ref code from snapapi
module which is opensource.
Its not something that is specific to any filesystem.
Regards.
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