Re: Linux-2.1.129.. not quite 2.2 yet, I hope.

Peter Benie (pjb1008@cam.ac.uk)
Thu, 26 Nov 1998 18:20:49 +0000


David Woodhouse writes ("Re: Linux-2.1.129.. not quite 2.2 yet, I hope. "):
>
> smurf@noris.de said:
> > Suppose that you have a server which has disks mounted on /archive, /
> > archive/.2, and /archive/.3 and so on. Mounting /archive will let the
> > client access /archive/.2 when the server uses the unfs daemon, but
> > with knfsd I _must_ mount /archive/.2 separately, on every client.
>
> With unfsd, you can get filehandle conflicts because NFS assumes that all
> inodes are on the same device - so the same inode # on different devices can
> get the same filehandle.

Allocating unique filehandles is easy to do correctly. The problem
is that when a client looks at the file attributes for over NFS, it
gets back a fsid (device) and a fileid (inode). There is no technical
reason why the client, if it knew to expect multiple devices, couldn't
map the fsid to a set of devices, rather than to a single device.
The minor difficulty is that you need to modify every NFS client that
has ever been written. The change to knfsd is trivial by comparison!

Peter

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