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Message-ID: <gqr50k$4aq$1@ger.gmane.org>
Date: Mon, 30 Mar 2009 15:02:44 -0400
From: Bill Davidsen <davidsen@....com>
To: linux-kernel@...r.kernel.org
Subject: Re: Linux 2.6.29
Andreas T.Auer wrote:
> On 30.03.2009 02:39 Theodore Tso wrote:
>> All I can do is apologize to all other filesystem developers profusely
>> for ext3's data=ordered semantics; at this point, I very much regret
>> that we made data=ordered the default for ext3. But the application
>> writers vastly outnumber us, and realistically we're not going to be
>> able to easily roll back eight years of application writers being
>> trained that fsync() is not necessary, and actually is detrimental for
>> ext3.
> And still I don't know any reason, why it makes sense to write the
> metadata to non-existing data immediately instead of delaying that, too.
>
Here I have the same question, I don't expect or demand that anything be done in
a particular order unless I force it so, and I expect there to be some corner
case where the data is written and the metadata doesn't reflect that in the
event of a failure, but I can't see that it ever a good idea to have the
metadata reflect the future and describe what things will look like if
everything goes as planned. I have had enough of that BS from financial planners
and politicians, metadata shouldn't try to predict the future just to save a ms
here or there. It's also necessary to have the metadata match reality after
fsync(), of course, or even the well behaved applications mentioned in this
thread haven't a hope of staying consistent.
Feel free to clarify why clairvoyant metadata is ever a good thing...
--
Bill Davidsen <davidsen@....com>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
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