From: Jan Kara <jack@suse.cz>
To: linux-ext4@vger.kernel.org
Cc: Bruce Guenter <bruce@untroubled.org>
Subject: Re: ext4 df regression introduced by commit 9d0be50
Date: Thu, 20 May 2010 18:11:21 +0200 [thread overview]
Message-ID: <20100520161121.GB28963@atrey.karlin.mff.cuni.cz> (raw)
In-Reply-To: <20100510180531.GA13538@untroubled.org>
Hi,
> I think I have found a regression introduced by commit 9d0be50 "ext4:
> Calculate metadata requirements more accurately".
Thanks for report!
> I am using ext4 on a NFSv4 server running unpatched kernel 2.6.33.3.
> The client is currently running unpatch 2.6.33.3, although I also saw
> the problem with the client running 2.6.32.10.
>
> The output from 'df' on the client varies wildly in the presence of
> certain writes. I have not pinned down an exact write pattern that
> causes it, but I do have an application that causes it fairly reliably.
> When the bug happens, I see swings like this:
>
> Sun May 9 23:04:58 2010 blocks=961173888 available=28183168
> Sun May 9 23:04:59 2010 blocks=961173888 available=12823424
> Sun May 9 23:05:00 2010 blocks=961173888 available=28183040
>
> (produced by a script that checks statvfs output every second; units are
> kB, df output is effectively identical)
Hmm, I'm not seeing anything obviously wrong with that patch but
apparently the number of blocks reserved for delayed allocation is
miscomputed by a lot...
Is your ext4 filesystem create from scratch or converted from ext3? Is
your application using lots of different files or rather a couple of small
ones? Anyways a reproducing program would be the best in this case...
Honza
--
Jan Kara <jack@suse.cz>
SuSE CR Labs
next prev parent reply other threads:[~2010-05-20 16:11 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-10 18:05 ext4 df regression introduced by commit 9d0be50 Bruce Guenter
2010-05-20 16:11 ` Jan Kara [this message]
2010-05-20 16:32 ` Bruce Guenter
2010-05-20 20:59 ` Bruce Guenter
2010-05-20 23:32 ` tytso
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