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SubjectRe: NFS Client patch
On Mon, 9 Jul 2001, Trond Myklebust wrote:
> The NFSv2 spec says no such thing. It simply says that you set the
> cookie to zero when you want to start at the beginning of the
> directory. This is only needed when we want to reread the directory
> into the page cache.

Ok, perhaps I mis-spoke slightly. What the spec does state is that the
cookie is opaque. This has generally been interpreted to mean that you
should not trust it to be stable after a change to that directory.

> Your patch will automatically lead to duplicate entries in readdir()
> on most if not all servers whenever the attributes on the inode have
> been refreshed (whether or not the cache has been invalidated). That's
> a bug...

If I were to do a create during a readdir() operation which inserted
itself in the directory before the place it left off, that entry would be
left out of the listing. That is also a bug, wouldn't you think?

I'd also like to point out that every other operating system which I have
tested this with has resulted in the correct behavior (NetBSD, FreeBSD,
Digital Unix, ...)

As for the refresh vs. invalidate problem, I would be happy to add
another time stamp to the in-core nfs inode exclusively for directory
invalidation.

Craig

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