[PATCH] Cascaded VFS for HEAD [v0.1]

Alexander Bokovoy a.bokovoy at sam-solutions.net
Fri Apr 12 10:03:02 GMT 2002

On Fri, Apr 12, 2002 at 05:47:26PM +0100, David Lee wrote:
> > Modules are specified in smb.conf using following syntax:
> > 
> > 	vfs object = module1 module2 ... modulen
> > 
> > Modules are loaded from left to right, making 'modulen' the topmost of
> > stack and module1 at bottom, just above standard Samba POSIX VFS module
> > which is built in.
> Can you clarify about order please?
> If I'm configuring a Samba server for our users, I envisage a data path
> starting at their PC/client and ending at the filesystem on the Samba/UNIX
> (or similar) machine.
> So I would naturally envisage that the data would arrive from the
> PC/client at module_1, then battle its way through the remaining modules
> towards module_n and (if all modules have succeeded) be passed into the
> UNIX servers filesystem.  In other words, I would expect the datapath from
> PC/client to samba/filesystem to traverse "vfs object = ..." in the same
> order that we humans read that line.
> But you seem to suggest the reverse: that the data path goes backwards
> along that line as we read it (PC/client data arrives first at module_n). 
> Have I mis-understood? 
Yes, modulen receives data first and module1 receives it last in queue.

> Perhaps a distinction is needed between "loaded" and "data processed"?
> It may be (I don't know) that VFS, as an internal detail, needs to load
> the modules in the reverse order to that which the PC-to-server datapath
> flows.
There are no internal constraints to keep processing right-to-left,
it can be easily changed to left-to-right way. 

What others think?

/ Alexander Bokovoy
Software architect and analyst             // SaM-Solutions Ltd.
When you're in command, command.
		-- Admiral Nimitz

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