Re: [nfsv4] Directory delegations, take 2

Nicolas Williams <Nicolas.Williams@Sun.COM> Thu, 23 October 2003 22:57 UTC

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From: Nicolas Williams <Nicolas.Williams@Sun.COM>
To: "Noveck, Dave" <Dave.Noveck@netapp.com>
Cc: Ted Anderson <TedAnderson@mindspring.com>, nfsv4@ietf.org, David.Robinson@Sun.COM
Subject: Re: [nfsv4] Directory delegations, take 2
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X-Original-Date: Thu, 23 Oct 2003 15:52:01 -0700
Date: Thu, 23 Oct 2003 15:52:01 -0700

As I see it, async directory notification delegations are merely a
performance improvement and has the effect of reducing the degree of
inconsistency of directory caches across multiple clients - whereas
synchronous directory notification delegations extend to the network one
more bit of traditional POSIX (and others) local filesystem semantics.

The two are different beasts that happen to share much of the
on-the-wire protocol.

So, the design of the notifications themselves could probably be
separated from the async vs. sync discussion.

The concern I'd expressed relates to the failure modes of synchronous
directory notification delegations.  But I think now that this is
manageable - Dave's post is convincing in this regard.

So, what are all the bits of POSIX filesystem semantics that NFSv4 is
missing but really ought to have?  (Here's one: O_APPEND  :/)

Cheers,

Nico
-- 

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