Re: [nfsv4] [Technical Errata Reported] RFC8166 (6528)

[David Noveck <[e-mail]>]

I believe this should be verified, but of course, having submitted it, I
would think that.  We need to hear from others who have looked at
rpc-over-rdma versioning issues and particularly from the authors of
rfc8166.

On Mon, Apr 12, 2021, 12:40 PM RFC Errata System <[e-mail]>
wrote:

> The following errata report has been submitted for RFC8166,
> "Remote Direct Memory Access Transport for Remote Procedure Call Version
> 1".
>
> --------------------------------------
> You may review the report below and at:
> https://www.rfc-editor.org/errata/eid6528
>
> --------------------------------------
> Type: Technical
> Reported by: David Noveck <[e-mail]>
>
> Section: 4.2.4
>
> Original Text
> -------------
> A Requester MUST NOT send an RPC-over-RDMA header with the RDMA_ERROR
> procedure.  A Responder MUST silently discard RDMA_ERROR procedures
>
> Corrected Text
> --------------
> An RDMA_ERROR header cannot be sent without an assurance that, the
> receiver
> has posted a receive operation which its sending will satisfy.  In most
> cases,
> this means that a Requester (i.e. one sending RPC Calls) MUST NOT send an
> RPC-over-RDMA header with the RDMA_ERROR procedure.  Similarly, a
> Responder
> (i.e. one sending RPC Replies) MUST silently discard RDMA_ERROR procedures.
>
> However, in the case of providing an RDMA_ERROR headers containing an
> error
> code of ERR_VERS, such a schema is not realizable, since there is no way
> for
> a receiver who does not support a particular version, to determine whether
> an RPC Call or Reply is being sent, leaving the receiver uncertain as to
> whether
> it is being Addressed as a Requester or a Responder, leaving it unable to
> participate in version negotiation.  In the case of version errors, the
> implementation is to rely on the assumption that  forward direction
> requests
> are being done and reserve direction requests only done once the version is
> properly negotiated.   As a result, such messages MUST NOT be sent by the
> client and MUST be silently discarded by servers.
>
> Notes
> -----
> Even if one feels that this is not an appropriate correction, the existing
> text must be fixed somehow.   In assuming that the terms Requester and
> Responder can be used this way in this context is likely to result in some
> implementers concluding that version errors can never be sent while other
> might be unabble to coonclude that given the effort expended in the spec to
> make such errors be interpretable by anf rpc-over-rdma version.
>
> Instructions:
> -------------
> This erratum is currently posted as "Reported". If necessary, please
> use "Reply All" to discuss whether it should be verified or
> rejected. When a decision is reached, the verifying party
> can log in to change the status and edit the report, if necessary.
>
> --------------------------------------
> RFC8166 (draft-ietf-nfsv4-rfc5666bis-11)
> --------------------------------------
> Title               : Remote Direct Memory Access Transport for Remote
> Procedure Call Version 1
> Publication Date    : June 2017
> Author(s)           : C. Lever, Ed., W. Simpson, T. Talpey
> Category            : PROPOSED STANDARD
> Source              : Network File System Version 4
> Area                : Transport
> Stream              : IETF
> Verifying Party     : IESG
>