samba - Aug 2010 - Shared file (.xls) not giving "File In Use" message

Hi all,

   I'm in the process of migrating an old aging NT4 server shares to
a samba server (compiled from source, version 3.5.4 on an Ubuntu 10.04
server). The vast majority of permissions, acls and behaviour 'issues'
I've managed to overcome with various settings on the shares - I think
Samba does an awesome job of a file server replacement.

   However on the testing phase I've come across an issue which is
considered a "show stopper". On the old NT file server if a 2nd
person attempts to open a file already being edited elsewhere that
user gets a "File In Use" dialogue which the users in the office use
extensively. However when I try the same operation on the new shiny
Samba server the 2nd file opens with no warning but in read only mode
(which is not deemed an exceptable 'replacement' to the old behaviour).

   Is this intended default behaviour or have I missed a compile/config
option?  I've tried fiddling about with setting oplocks, level 2 oplocks
and a few other settings and always see the same behaviour. Google-Fu
seems to show up the opposite to the issue ("File In Use" dialogues
when there is no 'lock' in place).

I have it as part of the NT4 domain with security = DOMAIN, and I
can set permissions and so on the unix side no problem (the files
are presently owned by DOMAIN\Administrator and Default Group
DOMAIN\Domain Users. So all seems fine.


The share in question has:

[Public]
        comment = Public Share
        path = /home/shares/Public
        read only = No
        create mask = 0770
        directory mask = 0770
        map acl inherit = Yes

smbclient shows:

Samba version 3.5.4
PID     Username      Group         Machine                        
-------------------------------------------------------------------
14252     davids        domain users  davids       (10.1.129.211)
14259     dravtest      domain users  dougpc       (10.2.1.227)

Service      pid     machine       Connected at
-------------------------------------------------------
Public       14252   davids        Fri Aug 27 12:43:54 2010
Public       14259   dougpc        Fri Aug 27 12:57:57 2010

Locked files:
Pid          Uid        DenyMode   Access      R/W        Oplock          
SharePath   Name   Time
--------------------------------------------------------------------------------------------------
14259        15003      DENY_NONE  0x100081    RDONLY     NONE            
/home/shares/Public   .   Fri Aug 27 12:57:57 2010
14252        15000      DENY_NONE  0x100081    RDONLY     NONE            
/home/shares/Public   .   Fri Aug 27 12:43:54 2010

Any thoughts on this?

Sorry if I ask the sort of question that's been asked before, but
google/ the last 5 months of this mailing list and the docs all have
shown up nothing!

Regards

D.