[PATCH 0/5] Dynamic Pseudo Root

[Trond Myklebust]

On Mon, 2008-02-18 at 19:38 +0100, Gabriel Barazer wrote:

> Maybe I'm completely wrong here, but how about having a v4rootfs 
> pseudo-filesystem ? This fs could have autogenerated directories built 
> with the export list and a fixed fsid to not break handles. Sure you 
> would have to put the export list into the kernel but only in this 
> filesystem code, not in the NFS mount code. This way you don't bloat the 
> current code, and gain the advantages of having a pseudofilesystem. 
> There is IMHO a real problem of having an external pseudoroot fs in 
> Linux for NFSv4 and the tmpfs/bind/using-a-real-fs-for-pseudoroot tricks 
> are more workarounds than real solutions. The cleaner way would be to 
> let the pseudofs handle that.

Why would this be any better than just using the real fs? Currently the
real information about who is allowed to see what is carried by the
_export list_, not the filesystem. By pushing information about
visibility into the filesystem, you are restricting the export list
topologies that can be supported.

For instance, currently with NFSv3, I can have rules like

/foo/bar	client1
/foo/bar/baz	client1, client2

How can you encode this topology if you want the pseudo-fs to be a
separate filesystem? You'd have to have 2 different namespaces, one for
client1, and one for client2.

Trond