[linux-lvm] "inactive Original" / "device-mapper: reload ioctl failed: Invalid argument"

[Marlier, Ian]

Hi there --

I've googled around and found other folks reporting this problem, but
haven't seen a solution.  I'm wondering if I'm missing something, or if
it's still an open issue...

I've got LVM2 set up, and am using snapshots.  After a reboot, the
master partition is listed with status "inactive Original", and the
snapshots as "inactive Snapshot".

/dev/mapper/volgrp-master exists, as does
/dev/mapper/volgrp-master-real.

Attempting to do anything with the master partition results in this
message:
"device-mapper: reload ioctl failed: Invalid argument"

Anyone know
1) What the problem might be?
2) What further diagnostics might be useful to figure out what the
problem is?
3) How to fix this?

Machine/version info:
devxen0:~ # uname -a
Linux devxen0 2.6.16.13-4-xen #1 SMP Wed May 3 04:53:23 UTC 2006 x86_64
x86_64 x86_64 GNU/Linux
devxen0:~ # lvm version
  LVM version:     2.02.02 (2006-02-07)
  Library version: 1.02.03 (2006-02-08)
  Driver version:  4.5.0
devxen0:~ # dmsetup version
Library version:   1.02.03 (2006-02-08)
Driver version:    4.5.0
devxen0:~ # lvscan
  inactive Original '/dev/xenmachines/master' [12.00 GB] inherit
  ACTIVE            '/dev/xenmachines/master-swap' [1.00 GB] inherit
  ACTIVE            '/dev/xenmachines/5-8-0-km-swap' [1.00 GB] inherit
  ACTIVE            '/dev/xenmachines/UberTix-swap' [1.00 GB] inherit
  ACTIVE            '/dev/xenmachines/FrancisTest-swap' [1.00 GB]
inherit
  inactive Snapshot '/dev/xenmachines/5-8-0-km' [10.00 GB] inherit
  inactive Snapshot '/dev/xenmachines/UberTix' [10.00 GB] inherit
  inactive Snapshot '/dev/xenmachines/FrancisTest' [10.00 GB] inherit
devxen0:~ #

Thanks!

- Ian