This patch changes our open specifically for clustering software. We must
allow root to access any volume or device with a LUN ID. We also modified
our revalidate function for this reason.
If a logical is reserved, we must register it with the OS with size=0. Then
the backup system can call BLKRRPART after breaking the reservation to
set the device to the correct size.
We also must register a controller with no logical volumes for the online
utilities to function. This is the way we've done it since the 2.2 kernel.
Which doesn't neccesarily make it right, but we have legacy apps to consider.

Signed off by: Mike Miller <mike.miller@hp.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>