Windows: Readonly Volume Versioning for Windows Cache Manager

Windows: Readonly Volume Versioning for Windows Cache Manager

When the HKLM\SYSTEM\CurrentControlSet\Services\TransarcAFSDaemon\Parameters
"ReadOnlyVolumeVersioning" DWORD registry value is non-zero, the volserver
will be queried for each .readonly volume to obtain the lastUpdateTime.
The lastUpdateTime will be used as a volume version identifier for each
cm_scache_t object stored in the volume.  With a known volume version,
whenever a current status is obtained for any object within the .readonly volume,
all the cached objects within that volume that have the same volume version
can share the resulting callback registration.

LICENSE MIT

Reviewed-on: http://gerrit.openafs.org/579
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Jeffrey Altman <jaltman@openafs.org>