Additional Unix (Linux/POSIX) Extensions to CIFS

George K Colley gcolley at
Thu Sep 18 15:44:02 GMT 2008

I would prefer to used a method blessed by Microsoft and documented.  
When I was up there we talked about having a vendor specific ioctl  
calls. The idea was Microsoft could control the registration but the  
vendors would control API used.

So what I would love to see is a way for the client to ask the server  
what  its native back end file system. So then the client could decide  
to use the default SMB2 NTFS API calls or the ones advertised by the  
server. So a server running on Linux, FreeBSD, or Apple could  
advertise these  APIs. So instead of sending NTFS API across the  
network, it could send whatevery APIs the server understand.

This doesn't change the protocol just the file system pass through  
apis. So the servers only need to support NTFS and their Native APIs  
and the client can decide which it would prefer to use.

Just my two cents worth,

On Sep 16, 2008, at 6:49 AM, Steve French wrote:

> On Tue, Sep 16, 2008 at 7:36 AM, simo <idra at> wrote:
>> On Tue, 2008-09-16 at 08:10 +0200, Volker Lendecke wrote:
>>> On Mon, Sep 15, 2008 at 04:51:50PM -0500, Steve French wrote:
>>>> Has anyone given more thought to what additional "Unix Extensions"
>>>> (extensions for better POSIX compat. and additional features for  
>>>> Linux
>> and
>>>> various Unix and Unix-like clients) are needed to the CIFS  
>>>> protocol?
>>> On a completely different topic: How are the unix extensions
>>> applied to SMB2?
> We have the same options as before, some combination of new  
> commands, new
> dialect and new info levels.   The obvious approach though would be  
> simply
> to map the Unix File Info levels to SMB2_QUERY_INFO and SMB2_SET_INFO.
> With SMB2 there is no SetPathInfo, and we don't need the hardlink  
> unix level
> (and probably don't need the symlink infolevel either). The  
> UnixQFSInfo
> could also be done via  SMB2_QUERY_INFO setting flag  
> and using the existing UnixQFSInfo level.   This should be fairly  
> easy to
> implement.
>> At SambaXP I asked Microsoft if they left space for unix extensions.
>> They said they haven't thought about that, but they were open to  
>> discuss
>> (and maybe even implement in Windows) unix extensions for SMB2.
> Yes - I had heard the same kind of answer from them.
> -- 
> Thanks,
> Steve

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