Hi Christoph,
    Many thanks for the quick response and the patch.  It was a big 
help.  I was able to repair our 60TB FS in about 30 hours. I have a 
couple of questions;

(1) The steps in the progress report seem a little strange.  See the 
attachment. Is this expected?

(2) This may be a little out of band but I have heard second hand 
reports from another sysadmin that the xfs tools which come with SLC5 
(our current Linux distro) should not be relied upon and that SLC6 
should be used.  Our 60TB FS is significantly fragmented (~40%) and I 
would very much like to run xfs_fsr on it.  Given that I have built the 
latest xfsprogs, is there any reason I should be afraid of running 
xfs_fsr, on the FS which comes with SLC5?  Unfortunately I don't have 
~60TB spare storage space elsewhere to backup the FS before defragging.  
What would you advise?

Many thanks
Tom.

Christoph Hellwig wrote:

Hi Tom,

On Wed, Feb 01, 2012 at 01:36:12PM +0000, Tom Crane wrote:
  

quoted

Dear XFS Support,
   I am attempting to use xfs_repair to fix a damaged FS but always
get a segfault if and only if -o ag_stride is specified. I have
tried ag_stride=2,8,16 & 32.  The FS is approx 60T. I can't find
reports of this particular problem on the mailing list archive.
Further details are;

xfs_repair version 3.1.7, recently downloaded via git repository.
uname -a
Linux store3 2.6.18-274.17.1.el5 #1 SMP Wed Jan 11 11:10:32 CET 2012
x86_64 x86_64 x86_64 GNU/Linux
    

Thanks for the detailed bug report.

Can you please try the attached patch?