[Samba] Question about Posix Locking and Windows XP/SP3 clients

[John_DeBella at notes.teradyne.com]

Hi,
                                                                            
 We have SAMBA 3.0.33 running on RedHat 5. We are sharing home directories  
 to users via Samba using the [homes] share. The home directories reside on 
 a Netapp filer, (actually multiple), and are accessed by the Samba server  
 over NFS. When  users try to open a Microsoft Excel file from a Windows XP 
 SP3 client, it is always opening as read-only because it thinks the file   
 is locked.  We have done some research on this as well as have discussed   
 this with RedHat and found that this is a result of "posix locking" which  
 is set to "yes" by default.                                                
                                                                            
 We have confirmed that turning it off does make the problem go away,       
 however, would like to know if this is safe to do in this                  
 configuration/scenario. I've come across some references on this but       
 nothing definitive to whether this would be ok or if this would be asking  
 for trouble. Given that the Samba server access and other potential access 
 to the files on the Netapp would be over NFS would the filer take care of  
 this sanely?                                                               
                                                                            
 Thanks for any information.                                                
                                                                            
 -John