Created attachment 454927 [details]
gfs2_hangalyzer output showing lost locks

Description of problem:
Customer reported GFS2 IO freeze.  Running gfs2_hangalyzer reports pid waiting for glock but no holder found.

Version-Release number of selected component (if applicable):
RHEL 5.5.z

How reproducible:
Customer generally ran in to this problem once a week.

Steps to Reproduce:
Details are not known yet exactly how to make it happen.  It seems to have to do with active/active mail server workload.

Actual results:
All IO on a specific GFS2 file system would eventually stop (or at least appear to stop).

Expected results:
IO doesn't stop.

Additional info:
Will attach gfs2_hangalyzer output with missing locks.  Gave customer 2.6.18-209.el5.x86_64.rpm test kernel and this appears to have fixed the lost locks part of this.