Re: [PATCH] ide write barrier support

From: Jens Axboe
Date: Fri Oct 17 2003 - 13:07:01 EST


On Fri, Oct 17 2003, Manfred Spraul wrote:
> Jens wrote:
>
> >The problem is that as far as I can see the best way to make fsync
> >really work is to make the last write a barrier write. That
> >automagically gets everything right for you - when the last block goes
> >to disk, you know the previous ones have already. And when the last
> >block completes, you know the whole lot is on platter.
> >
> Are you sure?
> What prevents the io scheduler from writing the last block before other
> blocks?

Very sure, the io scheduler will never put the barrier write before
previously comitted writes. So yes, it will work as described.

Jens

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