ms-nfs41 mount: Where does Unix_User+0 and Unix_Group+0 come from?

[Martin Wege]

Hello,

We are working to deploy the ms-nfs41-nfs-filesystem on our Windows
machines, and encounter some issues with Cygwin (latest stable).

For example, if we go to the ms-nfs41-nfs-filesystem (not the NFS
version 3 client from Windows!!!) with cd X: ; cd tmp/data9/, and do a
ls -l we get 'Unix_User+0' and 'Unix_Group+0' for user and group
names.
The question is: Where do these names come from - Windows,
ms-nfs41-nfs-filesystem or Cygwin?
getent passwd and getent group do not list this on Cygwin.
NFS version 4 server "lordbatman" has user mlw=uid(3620) and group mlw=gid(3620)

Steps to reproduce:
1. Download and install cygwin.
2. Download http://www.citi.umich.edu/projects/nfsv4/windows/120612/
and install it.
3. Start NFS version 4 client daemon:
ms-nfs41-client-x64/nfsd_debug.exe -d 3 --noldap --gid 3620 --uid 3620
4. Mount NFS version 4 directory:
ms-nfs41-client-x64/ms-nfs41-client-x64/nfs_mount.exe -p -o sec=sys X
'lordbatman.bias.dfn.de:/export/home/mlw'

Expectation:
Cygwin ls -l should list file user/group as mlw/mlw

Actual results:
Cygwin ls -l lists file user/group as Unix_User+0/Unix_Group+0

How do we fix this?

Thanks,
Martin