features in samba 3.alpha (VFS)

[David Lee]

On Sun, 2 Dec 2001, Tim Potter wrote:

> On Sun, Dec 02, 2001 at 12:15:26AM +0100, Rainer Link wrote:
> 
> > Ariel Mella wrote:
> > > what is the state and features of VFS in samba?
> > 
> > VFS works quite well for me. But I still can use only one VFS module per
> > share, even if I specify
> > two modules, the last one will be "active". Hum, I thought this would be
> > possible within Samba 3.0, but I haven't digged into it yet. Tim?
> 
> We didn't progress past the argument stage of stackable vfs modules.  (-:
> I think the consensus was that it was too hard to figure out the 
> semantics of how it would work.

That's a pity.  I seem to recall discussion recently about a possible
virus-scan VFS layer.  And I also recall reading somewhere (sorry, forget
where) that the "quotas" code would be an ideal candidate for VFS.

So already there are two potential VFS layers that could both be useful
within the same share. 

Semantics?  Might a useful starting-point be the model used by PAM
(Pluggable Authentication Modules) with its "requisite, required,
optional, sufficient" configuration options etc.  (Sure, we may well find
reasons why that is insufficient, but it may at least get our thinking
started...) 

As for reporting errors to the user, I am working on a proposal, and have
done some demonstration code, for a general messaging-service "Popup"
function in smbd, that could be used by several things including, but not
limited to, individual VFS modules and the VFS strucutre.  (Other
demonstrated uses include allowing UNIX "write(1)", "wall(1)" and
"shutdown(1m)" to work seamlessly onto our samba clients.) 

So I'd like to encourage those members of the Samba team who are thinking
about VFS to consider whether we can, somehow, support multiple VFS layers
per share.

-- 

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