When a samba server shares NFS4 mount directory, window clients cannot copy file. ERROR: 0x80070021

The error reported by windows client is like this ERROR: 0x80070021 The process cannot access the file because another process has locked a portion of the file.

I google it and hit samba bug report 8481 . Which is very similar to this problem. Another link also mentions a similar issue.

But, instead of NFSv3, my NFS backend is using NFSv4, provided by OpenSolaris ZFS file system.

I try to mount -t nfs4 -o nolock fileserver:/export/home /home, but it says no such option "nolock". nolock is only valid for NFSv3, not NFSv4.

1. fileserver: an OpenSolaris file server.
2. Linux server: Debian Lenny. Running samba service and mount /home to fileserver:/export/home
3. Windows client: it can browse the directories shared by the linux server, but cannot copy any files.

From what I found googling, this is a problem caused on NFS level, to fix it edit /etc/samba/smb.cfg and in the [global] section add the option:

strict locking = no