Re: NFS Client patch

Trond Myklebust (trond.myklebust@fys.uio.no)
Fri, 20 Jul 2001 10:50:57 +0200


>>>>> " " == Hans Reiser <reiser@namesys.com> writes:

> The current code does rely on hidden knowledge of the filesytem
> on the server, and refuses to operate with any FS that does not
> describe a position in a directory as an offset or hash that
> fits into 32 or 64 bits.

I'm not saying that ReiserFS is wrong to question the correctness of
this. I'm just saying that NFSv2 and v3 are fixed protocols, and that
it's too late to do anything about them. I read Chris mail as a
suggestion of creating yet another NQNFS, and this would IMHO be a
mistake. Better to concentrate on NFSv4 which is meant to be
extendible.

> But be calm, I am not planning on fixing this myself anytime in
> the next year, we have an ugly and hideous hack deployed in
> ReiserFS that works, for now I am just saying the folks who
> designed NFS did a bad job and resolutely continue doing a bad
> job, and if someone wanted to fix it, they could fix cookies to
> use filenames instead of byte offsets for those filesytems able
> to better use filenames than byte offsets to describe a
> position within a directory, and for those clients and servers
> who are both smart enough to understand filenames instead of
> cookies (able to understand the cookie monster protocol).

This is something which I believe you raised in the NFSv4 group, and
which could indeed be a candidate for an NFSv4 extension. After all,
this is in essence a recognition of the method most NFS clients
implement for recovering from an EBADCOOKIE error. Why was the idea
dropped?

(Note: As I said, under Linux we're currently hampered when
considering the above alternatives by the fact that glibc requires the
ability to lseek() on directories. This is a bug that they could
easily fix, and it affects not only your suggestion, but also all the
other suggestions in which one implements non-permanent cookies)

Cheers,
Trond
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/