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Re: [Nbd] [PATCHv5] docs/proto.md: Clarify SHOULD / MUST / MAY etc



On 04/06/2016 04:37 PM, Alex Bligh wrote:
> These are changes which possibly have semantic effect
> 
> * Clarify that SHOULD / MUST / MAY etc. when in capitals have an
>   RFC 2119 meaning using the wording within that RFC.
> 
> * Fix some lowercase use of these words which actually were
>   meant to be uppercase.
> 
> * Fix some lowercase 'should' which clearly meant 'MUST'; where
>   it's not obvious, I've made them 'SHOULD' or left them as is.
> 
> * Fix wording on transmission flags to be clearer.
> 
> Signed-off-by: Alex Bligh <alex@...872...>
> ---
>  doc/proto.md | 102 +++++++++++++++++++++++++++++++++++------------------------
>  1 file changed, 60 insertions(+), 42 deletions(-)
> @@ -752,20 +770,19 @@ Therefore these commands share common documentation.
>        server has multiple alternate names for a single export, or a
>        default export was specified.
>  
> -    The server MUST NOT fail an NDB_OPT_GO sent with the same parameters
> -    as a previous NBD_OPT_INFO which returned successfully (i.e. with
> +    The server MUST NOT fail an `NDB_OPT_GO` sent with the same parameters
> +    as a previous `NBD_OPT_INFO` which returned successfully (i.e. with
>      `NBD_REP_SERVER`) unless in the intervening time the client has
>      negotiated other options. The server MUST return the same transmission
> -    flags with NDB_OPT_GO as a previous NDB_OPT_INFO unless in the
> +    flags with `NDB_OPT_GO` as a previous `NDB_OPT_INFO` unless in the
>      intervening time the client has negotiated other options.

I failed to notice this earlier, but a server MAY send different
transmission flags if NBD_OPT_INFO(name1) is immediately followed by
NBD_OPT_GO(name2), with no intervening client options (because some of
the transmission flags, like read-only, are determined by the choice of
export name). The first sentence gets this right ("with the same
parameters"), the second does not (missing that phrase).

>      The values of the transmission flags MAY differ from what was sent
>      earlier in response to an earlier `NBD_OPT_INFO` (if any), and/or
>      the server MAY fail the request, based on other options that were
>      negotiated in the meantime.

And if we reword the second sentence, the third sentence may also need a
tweak.

However, it may be worth fixing that as a followup patch, and letting
this one through.

Everything else is looking good from my perspective.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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