linux-ext4 - RE: 2nd Attempt

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Date:	Fri, 3 May 2013 14:31:41 +0100
From:	"Stephen Elliott" <techweb@...world.com>
To:	"'Theodore Ts'o'" <tytso@....edu>
Cc:	"'Andreas Dilger'" <adilger@...ger.ca>,
	<linux-ext4@...r.kernel.org>
Subject: RE: 2nd Attempt - FSCK Errors

Well... Funny enough, the device which I ran debugfs on was the other
ReadyNAS device, not the one with the issue anyway. I wanted to test it
first.

I suspect the underlying architecture supporting RAID in these devices
screws with the debugfs interface.

I just find it bizarre that I get the same message regarding multiply
assigned blocks in 0 files on every FSCK as in it never gets resolved.
But... No issues with file access or no bad logs etc. I do have a case open
with Netgear support, since this is basically an appliance.

-----Original Message-----
From: Theodore Ts'o [mailto:tytso@....edu] 
Sent: 03 May 2013 14:14
To: Stephen Elliott
Cc: 'Andreas Dilger'; linux-ext4@...r.kernel.org
Subject: Re: 2nd Attempt - FSCK Errors

What you've shown us makes me suspicious about whether the hardware device
is sane or not.  In the previous e2fsck run, it set i_size to a non-zero
value.  Yet when debugfs tries to read the same inode, it's now seeing all
zero's.

So that implies the disk (or software raid device; you haven't been clear
what the underlying storage is for this file system) is not returning the
same information for a particular block as was previously written.

If the underlying block device is not stable, there really is nothing for
e2fsck to do.  You might want to check /var/log/messages for any error
messages relating to the underlying storage device(s).  If you're seeing I/O
errors in the log files, that would be another hint.

At this point, my recommendation to you is to find a separate disk (or RAID
array if necessary) which is as big as the underlying disk, and do an image
copy (via dd or ddrescue) to a known-good storage device, and then retry the
e2fsck on this copy of the file system.

Regards,

						- Ted

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