[nfsv4] AD review : draft-ietf-nfsv4-layoutwcc-02

[Zaheduzzaman Sarker <[e-mail]>]

Hi,



I have now reviewed the draft-ietf-nfsv4-layoutwcc and I think this
document need to improve the writing. Hence please respond to the comments
and resolve them.



I have done this review as If I don't really understand NFSv4 and NFSv3
(which might be anyway true) and tried to reflect on things that was
unclear in the description.



I hope this review helps and feel free to take the opportunity to educate
me.



//Zahed







My section by section comments are below -

====================================



# Abstract

    s/This document presents a refinement to RFC8435 to allow the client to
update the metadata server to changes on the data server/ This document
updates RFC8435 to allow the client to update the metadata server to
changes on the data server.



    This makes it clear that the current specification will update RFC 8435.



    However, to me it is still not super clear if we are updating RFC 8435
or extending RFC 7862. What is the rationale here for the update tag?



# Section 1



    My initial assumption was that we have a useful feature with WCC for
NFv3 that we would like to allow for NFv4 with LAYOUT-WCC. However, the
more I read Section 1 and Section 2, I am getting more confused as the
description of NFSv4 and NFv3 is very intertwined. Either my assumption is
wrong or the text should be improved, either case I think the following
would help.

        - let’s assume the reader will read this as a starting document (I
think this will be true for the most of the reviewers in the process)
hence, let's describe the scenario better for them and not assume they
understand and know the difference between NFv4 and NFSv3 by heart. Hence,
providing right reference is the right tools here. Also make sure we write

            - the version of NFS the metadata server is running or does it
even matter

            - short description of the WCC and reference the RFC for the
details

        - Lets keep all the NFv3 related details in the Introduction
section. This means describe some of the basic concepts those are described
in different sub-sections of section 2 in Section 1, and focus on NFSv4
specifics in section 2 and 3. This means already in introduction we write
the relation of NFSv3 GETATTR to NFv4 GETATRR and who sends them , etc. as
a base to understand the extension are doing in the rest of the sections.

        - Make sure we are specific about the extension we are doing in
this specification - are we writing this specification only for NFSv4
client or the client's NFV version does not matter? If the client learns
gid and uid from via NFSv3 how that is done and why that is important here.
This pops up if I read the following sentence -



                       "In this document, we introduce a new operation
called LAYOUT_WCC which allows the client to periodically report the
attributes of the data files to the metadata server."





# Section 2.1



    Please provide the reference to the data types of the structs



# Section 2.3



    It not clear if the extension is for NFSv4 only or it can also replace
WCC for NFSv3.



    Why are first 3 paragraph relevant at all? what is the relation of this
description to the extension?



    Overall, sometimes it is not clear in the text on who does what. I
think we can do a better job of stating what is client's responsibility and
what is metadata server's. This might be get cleared automatically when we
have a better split between the section 1 and section 2



# Section 2.4.1



    - Please provide reference to mtime, atime and all the attribute
mentioned (size, space_used, change, time_access, time_metadata, and
time_modify.).

    - it says -



            Whenever it sends an NFS4ERR_ACCESS error via LAYOUTRETURN or
LAYOUTERROR - it could have already gotten the NFSv3 uid and gid values
back in the WCC of the WRITE, READ, or COMMIT operation which got the error.



        I am a bit confused here, just reading the text here, are you
saying the client had got some attributes via NFSv3 but when error occurs
it uses NFv4 LAYOUT-WCC to report?



# Section 2.5



    We should be very clear that we are not defining any new ERROR for
LAYOUT_WCC if that is the case and reference to where the errors are
defined. Otherwise, we need to explain each and every errors here in this
document, that would be cumbersome or repeating.



# Section 5 IANA considerations :



    Please provide more details on which IANA registry to be
updated/amended for the new entries.