Allow snapdiff backups of NetApp CIFS volumes containing widelinks

TSM uses NetUseEnum() to determine if a NetApp CIFS share is connected before attempting a snapdiff backup. When run on a NetApp CIFS volume with widelinks, it results in the following error:

ANS2831E: Incremental by snapshot difference cannot be performed on 'volume-name' as it is not a NetApp NFS or CIFS volume.

This is because "...The NetUseEnum function does not support Distributed File System (DFS) shares. To enumerate shares using a different network provider (WebDAV or a DFS share, for example), use the WNetOpenEnum, WNetEnumResource, and WNetCloseEnum functions."

NetUseEnum function
http://msdn.microsoft.com/en-us/library/windows/desktop/aa370647(v=vs.85).aspx

Additional details on widelinks can be found at
https://library.netapp.com/ecmdocs/ECMM1277928/html/filesag/multi8.htm

Below is an example 'net use' of a NetApp CIFS share with widelinks enabled:

-
New connections will be remembered.


Status Local Remote Network

-------------------------------------------------------------------------------
\\server\share_with_widelinks
Microsoft Windows Network
The command completed successfully.
-

Notice that the status column is empty - this is because 'net use' uses the NetUseEnum() function to check connectivity.

When widelinks are enabled on a NetApp CIFS share, it behaves as a DFS root to clients. This means any connections to it will not be found when calling NetUseEnum(). According to Microsoft's own documentation, the fix is to "use the WNetOpenEnum, WNetEnumResource, and WNetCloseEnum functions."

WNetOpenEnum
http://msdn.microsoft.com/en-us/library/windows/desktop/aa385478(v=vs.85).aspx

WNetEnumResource
http://msdn.microsoft.com/en-us/library/windows/desktop/aa385449(v=vs.85).aspx

WNetCloseEnum
http://msdn.microsoft.com/en-us/library/windows/desktop/aa385431(v=vs.85).aspx

Enumerating Network Resources
http://msdn.microsoft.com/en-us/library/windows/desktop/aa385341(v=vs.85).aspx

Can an option be added to TSM to have the Windows client use the WNet* functions instead of NetUseEnum? This would allow snapdiff backups to work on a CIFS NetApp volume that has widelinks enabled. This option could be exclusive to snapdiff backups (e.g., -snapdiff -widelinks).