Subject: RE: [nfsv4] Question On the' Access' and 'Supported' bitmasks in the NFSV4 Access Operation

From: "Noveck, Dave" <[email-masked]>
Date: Thu, 29 Jan 2004 11:49:54 -0800

So let's talk about this in terms of the sets R, S, and A, denoted the requested set in the argument, the supported bit mask in the result and the access bit mask in the result, respectively.
 
Let's use <:= to approximate an is-a-subset-of sign (not necessarily proper)
 
The spec says (sec 14.3.1 DESCRIPTION para 2):
 
Note that the supported field will contain only as many values as were originally sent in the arguments.
 
So S <:= R
 
The spec does not make an analogous remark about the access field, but it does indicate (in the last paragraph of that section) that any bit that is on A that is not on in S, must be ignored by the client and is thus basically noise.
 
So if it isn't the case that A <:= S <:= R, then set A' to the intersection of A and S, and then A' becomes the only part of A that the client may validly look at, and it must be the case that A' <:= S <:= R.

-----Original Message-----
From: Kaukab Uddin [mailto:[email-masked]]
Sent: Thursday, January 29, 2004 2:11 PM
To: [email-masked]
Cc: Michael Bull
Subject: [nfsv4] Question On the' Access' and 'Supported' bitmasks in the NFSV4 Access Operation

Just trying to validate our understanding on these two bitmasks:

1) We interpret the 'access' bitmask to reflect all supported rights for that
user with respect to the file; irrespective of what has been requested.

2) We interpret the 'supported' bitmask to reflect rights that have been requested
and can be supported by the server for that user.

Is our interpretation correct?

Regards;
Kaukab