Hello everyone,
this is not a question, it's a solution. I had to search tons of old mailing lists till I accidentally stumbled across the solution for this problem and I want to spare other's the effort.
The problem is the following:
When Samba shares a folder that is mounted using NFS (v4 in my case), then Windows Clients are unable to write to the file unless the setgid bit is set. Windows clients can create and delete the file, but not write to an already opened file. Linux clients to not appear to be afflicted by the problem.
To fix this, I first tried to force all clients to set the setgid bit using force create mode = 02000 in the config file. Again, this only worked for linux clients. Windows clients ignored the directive somehow.
The problem is rooted in the way samba and nfs file locking conflicts. To make it work, the strict locking feature of samba needs to be turned of. Appending the following to my smb.conf's general section fixed the problem:
Code:
...
lock directory = /var/lock/samba
locking = yes
strict locking = no
...
Hope this helps someone.
Cheers.