Re: bug in md write barrier support?

[Alan Cox]

On Iau, 2004-09-09 at 09:29, Jens Axboe wrote:
> > why does this seem broken? semantics of "cache flush guarantees that all
> > io submitted prior to it hits the spindle" are quite sane imo; no
> > guarantee of later submitted IO.. compare the unix "sync" command; same
> > level of semantics.
> 
> Depends on your angle, I think it breaks the principle of least
> surprise.

As far as I can ascertain raid controllers in general follow this set of
semantics. Its less of an issue for many of them with battery backup
obviously.

It also makes a lot of sense at the hardware level for performance
especially when dealing with raid.

Alan

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