From: Dave Chinner <david@fromorbit.com>
To: Leo Davis <leo1783@yahoo.com>
Cc: xfs@oss.sgi.com
Subject: Re: fs corruption
Date: Tue, 12 Apr 2011 21:05:32 +1000 [thread overview]
Message-ID: <20110412110532.GB31057@dastard> (raw)
In-Reply-To: <38287.10078.qm@web112901.mail.gq1.yahoo.com>
On Tue, Apr 12, 2011 at 03:51:20AM -0700, Leo Davis wrote:
> You have a corrupted free space btree.
>
> Err... apologies for my ignorance, but what is a free space btree?
A tree that indexes the free space in the filesystem. Every time you
write a file or remove a file you are allocating or freeing space,
and these tree keep track of that free space.
If you want to know - at a high level - how XFS is structured (good
for understanding what a free space tree is), read this paper:
http://oss.sgi.com/projects/xfs/papers/xfs_usenix/index.html
It's from 1996, but still correct on all the major structural
details.
> I had serial trace from raid controller which i just checked and
> it logged some 'Loose cabling', but this was months back..... not
> sure whether that can be the cause of this.. strange if that is
> the case since it's been a long time
it's possible that it took a couple of months to trip over a random
metadata corruption. I've seen that before in directory trees and
inode clusters where corruption is not detected until next time they
are read from disk....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2011-04-12 11:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-12 9:33 fs corruption stress_buster
2011-04-12 9:49 ` Dave Chinner
2011-04-12 10:51 ` Leo Davis
2011-04-12 11:05 ` Dave Chinner [this message]
2011-04-12 11:37 ` Emmanuel Florac
-- strict thread matches above, loose matches on Subject: below --
2011-04-25 5:47 Leo Davis
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