Andrew Gabriel wrote:
> In article ,
> "Gary R. Schmidt" writes:
>> Dave Uhring wrote:
>>> On Sun, 11 May 2008 16:39:15 +0000, Andrew Gabriel wrote:
>>>
>>>> Solaris will fall back to NFSv3 and NFSv2 if NFSv4 isn't supported.
>>>> If the server does have NFSv4 enabled but it's not working right, then
>>>> there's no fallback -- that's not what the fallback is intended for.
>>> OK, perhaps the Linux NFS server is the real problem then. I thought that
>>> I had disabled NFSv4 on that server but
>>>
>>> [root@newton /proc/17856]# cat status
>>> Name: nfsd4
>>>
>>> I never did trust Linux NFS very much but that machine is my print server
>>> also and the printer requires HPLIP, which will not build on Solaris.
>>>
>> The Linux NFSv4 server does *not* fall back to NFSv3 when it is not set
>> up to do authentication and all the trimmings of NFSv4. I can't
>> remember the exact sequence, but it basically sends back a failure
>> status rather than a "try again".
>
> That's correct behaviour -- NFS servers have no way to fall back.
> It's the clients which fall back, but this is to cope with systems
> which haven't implemented NFSv4 (or NFSv3), not for working around
> buggy implementations. A client has a not unreasonable expecation
> that if a server offers NFSv4, it's a working implementation.
>
Yes, bad explanation by me, I'll try again...

The Linux NFSv4 server, when receiving a mount request from *any* NFSv4
client before it has had its authentication configured returns to the
client "no such share," or something to that effect which the client
sees as "don't try again, it won't work," instead of sending "I don't
like you" or "I don't understand you," which would allow the client to
try again at NFSv3 (or v2) and succeed.

Amusingly enough, the authentication failure *is* flagged as such within
the server, but on the way up it gets changed to a terminal value!!!

IIRC, we (I work for another computer company of three letters that
starts with 'S') have "fixed" this in our enhanced NFS server, but I
can't recall if we have pushed the changes up-stream yet, or if they
have been accepted... No, I take that back, I think we *hacked* in some
changes and sniffed the data stream to prove what was going on and then
put the bug on the "to be fixed" list, which is, ahem, rather long. IOW
- don't hold your breath waiting for it to be fixed!

Cheers,
Gary B-)

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