Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 4 Sep 2003 12:12:55 -0700 | From | Mike Fedyk <> | Subject | Re: precise characterization of ext3 atomicity |
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On Thu, Sep 04, 2003 at 10:37:10PM +0400, Hans Reiser wrote: > Mike Fedyk wrote: > > >On Thu, Sep 04, 2003 at 08:25:18PM +0400, Hans Reiser wrote: > > > > > >>In data=journal and data=ordered modes ext3 also guarantees that the > >>metadata will be committed atomically with the data they point to. > >>However ext3 does not provide user data atomicity guarantees beyond the > >>scope of a single filesystem disk block (usually 4 kilobytes). If a > >>single write() spans two disk blocks it is possible that a crash partway > >>through the write will result in only one of those blocks appearing in > >>the file after recovery. > >> > >> > > > >And how does reiser4 do this without changing the userspace apps? > > > We don't. We just make the hovercraft, we don't force you to go over > the water.....
So by default with no user space modifications, reiser4 will be atomic for each write() call, and ext3 will if it aligns withing a single page.
Is that correct?
Then you can go on to specify that you can have larger transactions if you make some changes to the userspace apps. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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