[Drbd-dev] FLUSH/FUA documentation & code discrepancy

Tejun Heo tj at kernel.org
Wed Sep 12 20:58:24 CEST 2012


Hello,

On Tue, Sep 11, 2012 at 10:25:01AM +0200, Lars Ellenberg wrote:
> Or do we have a better place to document write ordering requirements?
> 
> "To enforce write-after-write dependencies, you *have* to drain the
> queue (do we have a generic interface available for that?),
> or at least wait for the completion of all the requests you
> (potentially) depend upon, before even submitting the dependent request.
> 
> Additionally, to avoid integrity issues due to volatile caches,
> you need to use FLUSH/FUA as appropriate."

I think it would be best to note the lack of any ordering guarantee in
the comment of bio_submit()?  Any one interested in submitting a
patch?

Thanks.

-- 
tejun


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