[nfsv4] Is "skip by 1" allowed for the NFSv4.0 seqid?

[Rick Macklem]

Here is the response on nfsv4 at ietf.org. I think the Redhat client
is broken from reading this. It will be interesting to see if anyone
working on the Linux client responds.

rick

----- Original Message -----
> > Is "skip by 1" allowed for NFv4.0 seqid?
> 
> No it isn't. As you indicated RFC7530, which obsoletes RFC3530,, indicates
> you are'
> only allowed to increment by one, with the exception of the wraparound case.
> 
> > I'll admit the wording in RFC-3530 isn't ideal,
> 
> I think the text "(r == L+2)" is intended to be read as "(e.g. r == L+2)" but
> the existing text
> is unclear.
> 
> > but I've never heard of this interpretation before .
> 
> Me either.
> 
> > Is an NFSv4.0 server supposed to accept both 0 and 1 as the
> correct next sequence # after UINT32_MAX?
> 
> I would say it isn't.  RFC7530 says "If th e sequence value received is any
> other
> value, it is rejected with the return of error NFS4ERR_BAD_SEQID"  In this
> case
> the correct value is 1.  On the other hand, this isn't a "MUST".  If there
> are clients out
> out there that don't do seqid wraparound correctly, it is seems like a
> reasonable
> accommodation for a server to accept the incorrect value zero in this case.,
> 
> 
> 
> 
> 
> 
> On Wed, Jul 1, 2015 at 9:22 PM, Rick Macklem < rmacklem at uoguelph.ca > wrote:
> 
> 
> Hi,
> 
> If you look here (on page #6) it seems to indicate that
> incrementing the seqid by 2 is allowed by the RFC.
> (I'll admit the wording in RFC-3530 isn't ideal, but I've
> never heard of this interpretation before.)
> https://dl.dropboxusercontent.com/u/51939288/nfs4-bad-seq.pdf
> 
> RFC-7530 seems clear that it should only be incremented by 1.
> However, I do notice that a wraparound of the seqid is supposed
> to skip 0 and go to 1. I don't see any mention of this in RFC-3530.
> --> Is an NFSv4.0 server supposed to accept both 0 and 1 as the
> correct next sequence # after UINT32_MAX?
> 
> Thanks for any help clarifying this, rick
> 
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