[nfsv4] [FedFS] XDR encoding of path "/"

James Lentini <jlentini@netapp.com> Wed, 13 October 2010 14:16 UTC

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Date: Wed, 13 Oct 2010 10:17:08 -0400 (EDT)
From: James Lentini <jlentini@netapp.com>
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Subject: [nfsv4] [FedFS] XDR encoding of path "/"
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At the BAT, Chuck Lever and I discussed what the pathname4 encoding of 
"/" should be.

In addition to being used by the fs_locations and fs_locations_info 
attributes, the pathname4 format is used by the fedfsNfsPath LDAP 
attribute (see Section 4.2.1.14 of 
draft-ietf-nfsv4-federated-fs-protocol-09), and the FedFsPathName XDR 
type (see draft-ietf-nfsv4-federated-fs-admin-07).

I'm aware of two different approaches to encoding "/".

One interpretation is to encode an array with zero compnent4 values. 
This encoding is a single 32-bit field containing a 0. The Linux NFS 
server and the SNSDB tools use this format.

Another interpretation is to encode an array with one zero-length 
component4 value. The encoding of this is a 32-bit field containing a 
1 followed by a 32-bit field containing a 0.

The Linux NFS client appears to accept both of these encodings for 
"/".

Are there any implementations using a different encoding than the ones 
above?

I'm thinking it would make sense to record these different formats or 
recommend the use of a specific format in one (or both) of the FedFS 
specifications.

-james