mounts sometimes take forever

["Christian, Chip" <chip.christian@storageapps.com>]

Has anyone seen "mount -f xfs /dev/blah /blah" take an extremely long time , possibly an eternity, to complete?  

We're running 2.4.3-SGI_XFS_1.0.1 #1 SMP, i686, RedHat Linux 7.1 on a pair of servers, in an HA fashion.  

When node #1 notes that node #2 isn't responding, he mounts all of node #2's filesystems.  What we have seen happen exactly twice now (out of many, many more successful mounts) is that a mount of one of the filesystems takes a long time, long enough that the user gave up and rebooted.  In one instance, the mount command ate 25 minutes of cpu in 30 minutes before we aborted.  mount was in state RN.

Is there anything anyone can think of I might try to diagnose this if it happens again?  strace and ltrace are useless; we're sitting inside mount().  Anything else I can use to see what's going on?

Could it be a timing thing, where node #2 is coming down and is in the process of umounting the filesystem while node #1 starts to mount the same filesystem?  

Thanks for any and all assistance.

	-Chip