samba - Jul 2008 - Rename to open file doesn't work, why?

Hello,

this may be a question a thousand times answered but I did not find 
it ...

On a local linux filesystem like ext2/3 one can rename a file to an 
existing, already open file. 

But this doesn't  work on a cifs-mounted samba-share - or do I miss 
something in the samba configuration. Attached ist a small 
test-program that does essentially the same as kmail does when it 
creates a mail-index file (and crashes ...)

Here you can see the versions (from the clients /proc/fs/cifs/):

Display Internal CIFS Data Structures for Debugging
---------------------------------------------------
CIFS Version 1.52
Active VFS Requests: 0
Servers:
1) Name: 192.168.32.12 ?Domain: KMUX Mounts: 1 OS: Unix
? ? ? ? NOS: Samba 3.0.24 ? ? ? Capability: 0x80f3fd
? ? ? ? SMB session status: 1 ? TCP status: 1
? ? ? ? Local Users To Server: 1 SecMode: 0x3 Req On Wire: 0
MIDs:

Shares:
1) \\192.168.32.12\hugo.tester Uses: 1 Type: NTFS DevInfo: 0x0 
Attributes: 0x2b
PathComponentMax: 255 Status: 1 type: 0

TIA
-- 
Wilhelm

Wilhelm Meier wrote:
> <snip>
> On a local linux filesystem like ext2/3 one can rename a file to an 
> existing, already open file. 
>
> But this doesn't  work on a cifs-mounted samba-share
> <snip>
>   
The reason this works with ext2 is that as long as you hold an open file 
descriptor a deleted file is still accessible (rename is essentially a 
delete and then a move).

While it might be theoretically possible for this to work unix to unix, 
Windows doesn't deal with deleted files the same way (it prevents you 
from deleting files as long as they are open), and so it's quite 
possible that SMB/CIFS doesn't understand the concept of having a 
deleted file open.


*Michael Heydon - IT Administrator *
michaelh@jaswin.com.au <mailto:michaelh@jaswin.com.au>