XFS appears to cause strange hang with md raid1 on reboot

[Ben Myers]

Hey Tom,

On Mon, Jan 28, 2013 at 06:28:18PM -0500, Tom wrote:
> I have been using XFS for many years, starting on IRIX and then on RedHat
> 7.2, and now on CentOS/RHEL and Ubuntu.  Last time I posted to this
> mailing list was 12 years ago.  :-)  I've been a happy customer!

I'm glad to hear it!  ;)

> Much more detail is available here (CentOS bug id 0006217) including steps
> to reproduce the problem.  Also testing with and without md raid.
> http://bugs.centos.org/view.php?id=6217
> 
> The one thing I haven't provided is a traceback.  I can provide that if it
> would be helpful.

I took a brief look at your report.  I think a traceback would be helpful.  

echo t > /proc/sysrq-trigger should do the trick.  You're in the middle of
unmount so you might need to go serial console to capture the output.  Your
report metions freeze/thaw.  This is an area where we've had deadlocks in the
past, so I wouldn't be surprised if that is what you're hitting.  We'll have to
see.

Thanks,
	Ben