NFS Locking violates protocol spec (incompatible with FreeBSD)

NFS Locking violates protocol spec (incompatible with FreeBSD)

[Kris Kennaway]

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Hello,

In http://lxr.linux.no/source/include/linux/lockd/xdr.h?v=2.6.0-test7
can be found the following comment:

35 /*
36  *      NLM cookies. Technically they can be 1K, Nobody uses over 8 bytes
37  *      however.
38  */
39  
40 struct nlm_cookie
41 {
42         unsigned char data[8];
43         unsigned int len;
44 };

Unfortunately, this is incorrect: FreeBSD 5.x's rpc.lockd uses a 16
byte cookie, and therefore FreeBSD 5.x NFS clients cannot interoperate
with Linux when NFS locking is enabled.

  http://www.freebsd.org/cgi/query-pr.cgi?pr=kern/56461

contains more details about this problem, including a workaround for
FreeBSD to limit the cookie size to 8 bytes.  Obviously, it would be
better for this bug to be fixed in Linux, since Linux is
non-conformant to the protocol.

Kris



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Re: NFS Locking violates protocol spec (incompatible with FreeBSD)

[Trond Myklebust]

>>>>> " " == Kris Kennaway <kris@freebsd.org> writes:


     > contains more details about this problem, including a
     > workaround for FreeBSD to limit the cookie size to 8 bytes.
     > Obviously, it would be better for this bug to be fixed in
     > Linux, since Linux is non-conformant to the protocol.

Yes. I saw a mail with a justification for why you want to be able to
wait on > 2^64 outstanding lock requests to a single lockd server, and
was highly amused.
I'm still hoping the person who decided that he needed 1024 byte
long cookies will own up some day. OTOH, he might still be busy
testing his locking code for cookie wraparound...


Anyhow, a patch exists (written by Greg Banks), and can be found as

 http://www.fys.uio.no/~trondmy/src/Linux-2.4.x/2.4.23-pre9/linux-2.4.23-01-fix_osx.dif


No. It does not extend the cookie size to 1k...

Cheers,
  Trond

Re: NFS Locking violates protocol spec (incompatible with FreeBSD)

[Kris Kennaway]

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On Thu, Nov 06, 2003 at 11:46:48PM -0500, Trond Myklebust wrote:
> >>>>> " " == Kris Kennaway <kris@freebsd.org> writes:
> 
> 
>      > contains more details about this problem, including a
>      > workaround for FreeBSD to limit the cookie size to 8 bytes.
>      > Obviously, it would be better for this bug to be fixed in
>      > Linux, since Linux is non-conformant to the protocol.
> 
> Yes. I saw a mail with a justification for why you want to be able to
> wait on > 2^64 outstanding lock requests to a single lockd server, and
> was highly amused.
> I'm still hoping the person who decided that he needed 1024 byte
> long cookies will own up some day. OTOH, he might still be busy
> testing his locking code for cookie wraparound...
> 
> 
> Anyhow, a patch exists (written by Greg Banks), and can be found as
> 
>  http://www.fys.uio.no/~trondmy/src/Linux-2.4.x/2.4.23-pre9/linux-2.4.23-01-fix_osx.dif
> 
> 
> No. It does not extend the cookie size to 1k...

Thanks..obviously we'd like a fix to be committed to Linux so that it
interoperates out of the box with FreeBSD.  What are the chances of
this?

Kris

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Re: NFS Locking violates protocol spec (incompatible with FreeBSD)

[Trond Myklebust]

>>>>> " " == Kris Kennaway <kris@obsecurity.org> writes:

     > Thanks..obviously we'd like a fix to be committed to Linux so
     > that it interoperates out of the box with FreeBSD.  What are
     > the chances of this?

For the moment I'm still waiting for confirmation that this patch does
actually fix the problem on both FreeBSD and OSX/Panther. Once that is
done, it's up to Marcelo to tell me when he wants it into 2.4.x. He
has already announce that he only wants critical bugfixes in 2.4.23,
though, so I would guess that we will have to wait for 2.4.24.

As for 2.6.x, I expect we will have to wait until the code freeze
lifts. When it does, I already have a backlog of lockd bugfixes to
port forward from 2.4.x, so it will make sense to merge it together
with that.

Then we just have to wait for the distributions to catch up ;-)

Cheers,
  Trond

Re: NFS Locking violates protocol spec (incompatible with FreeBSD)

[Kris Kennaway]

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On Fri, Nov 07, 2003 at 01:13:10AM -0500, Trond Myklebust wrote:
> >>>>> " " == Kris Kennaway <kris@obsecurity.org> writes:
> 
>      > Thanks..obviously we'd like a fix to be committed to Linux so
>      > that it interoperates out of the box with FreeBSD.  What are
>      > the chances of this?
> 
> For the moment I'm still waiting for confirmation that this patch does
> actually fix the problem on both FreeBSD and OSX/Panther. Once that is
> done, it's up to Marcelo to tell me when he wants it into 2.4.x. He
> has already announce that he only wants critical bugfixes in 2.4.23,
> though, so I would guess that we will have to wait for 2.4.24.
> 
> As for 2.6.x, I expect we will have to wait until the code freeze
> lifts. When it does, I already have a backlog of lockd bugfixes to
> port forward from 2.4.x, so it will make sense to merge it together
> with that.
> 
> Then we just have to wait for the distributions to catch up ;-)

Thanks.  Unfortunately the Linux server I experience this problem with
is not something I can play with, but I've CC'ed two people who
experience this problem with FreeBSD: perhaps they can test the patch
(http://www.fys.uio.no/~trondmy/src/Linux-2.4.x/2.4.23-pre9/linux-2.4.23-01-fix_osx.dif)

Kris

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