Subject: Re: New hash algorithm - FNV - for use in the kernel
To: David Laight <>
From: Bill Studenmund <>
List: tech-kern
Date: 11/28/2001 12:21:16
On Wed, 28 Nov 2001, Jonathan Stone wrote:

> In message <010e01c177f6$72840780$0100a8c0@snowdrop>"David Laight" writes
> [snip nfs basics]
> >For NFS V1 (I think it's V1) the NFS spec defines the length of the
> >file handle, the number of ways the above information can be stashed
> >in the available space is limited...
> V2. (V1 hardly ever saw the light of day; the Suns i used went from
> "nd" to nfsv2).
> Point is, someone suggested, in essence, grab *just* the "inode
> number" (or moral equivalent) out of the NFS file-handle, and hash
> that".  But RFC1094 says that file handles are opaque, 32-bit
> quantities. But there are several distinct NFS V2 implementations.
> Those different implementations put their "inode" data in different
> locations within the opaque 32-byte field.
> And there is *no reliable way* for NFS clients to ascertain which
> particular NFS implementation an NFS server is using, or whereabouts
> the server stashes the "inode number".

Plus there's the fact that file systems are moving to having 64-bit inode
numbers, so there is no good 32-bit quantity to grab. :-)

Take care,