Re: True fsync() in Linux (on IDE)

From: Chris Mason
Date: Fri Mar 19 2004 - 08:51:21 EST


On Fri, 2004-03-19 at 03:05, Hans Reiser wrote:
> Chris Mason wrote:
>
> >On Thu, 2004-03-18 at 16:09, Peter Zaitsev wrote:
> >
> >
> >>On Thu, 2004-03-18 at 13:02, Chris Mason wrote:
> >>
> >>
> >>
> >>>>In the former case cache is surely not flushed.
> >>>>
> >>>>
> >>>>
> >>>Hmmm, is it reiser? For both 2.4 reiserfs and ext3, the flush happens
> >>>when you commit. ext3 always commits on fsync and reiser only commits
> >>>when you've changed metadata.
> >>>
> >>>
> >>Oh. Yes. This is Reiser, I did not think it is FS issue.
> >>I'll know to stay away from ReiserFS now.
> >>
> >>
> >
> >For reiserfs data=ordered should be enough to trigger the needed
> >commits. If not, data=journal. Note that neither fs does barriers for
> >O_SYNC, so we're just not perfect in 2.4.
> >
> >-chris
> >
> You are not listening to Peter. As I understand it from what Peter says
> and your words, your implementation is wrong, and makes fsync
> meaningless. If so, then you need to fix it. fsync should not be
> meaningless even for metadata only journaling. This is a serious bug
> that needs immediate correction, if Peter and I understand it correctly
> from your words.

I am listening to Peter, Jens and I have spent a significant amount of
time on this code. We can go back and spend many more hours testing and
debugging the 2.4 changes, or we can go forward with a very nice
solution in 2.6.

I'm planning on going forward with 2.6

-chris


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