[Samba] linux-to-linux samba weird problem

[Jeremy Allison]

On Wed, Feb 27, 2013 at 04:00:23PM -0500, Neal Murphy wrote:
> I've a weird problem with Samba. I'm using Samba to share a filesystem between 
> two linux systems because I believe I need byte range locking to prevent 
> multiple processes on different computers from reading/writing the same ISAM 
> records.
> 
> I have a Debian wheezy file server running Samba; no domain controller, just a 
> simple, single share. I have a debian wheezy KVM mounting a share via CIFS, 
> forcing UID and GID; UID/GID are the same on the two systems. I use a 
> credentials file with non-root user and password. I disabled oplocks and 
> client caching. The shared dir has ug+rw for all files, and has ug+x for all 
> dirs; the same non-root user and group owns all files and dirs. I've even gone 
> so far as to add ug+s on all dirs, to no avail. General access seems to be OK. 
> But there's a failure in one specific instance.
> 
> On the KVM, I'm running unibasic (business basic). I wrote a program to test 
> record locking when reading indexed ISAM files. Running it on two KVMs, I 
> verified that record locking does work; the lock passed between the two 
> programs very nicely. But I encountered a problem when creating indexed ISAM 
> files.
> 
> When a UB program builds an indexed ISAM DB, it creates both a data file and 
> an index file on the file server. The problem is that it *always* fails when a 
> non-root user runs unibasic (it can't create the index structure within the 
> index file). But it succeeds when running the program as root. Oddly, if I 
> leave ug+s off the dirs on the server, root:root will own one of the files in 
> the pair (regardless of forceuid/forcegid on the client mount).

How exactly does it fail ? This will help determine the problem.