On 03/28/2016 04:43 AM, Denis V. Lunev wrote:
> From: Pavel Borzenkov <pborzenkov@virtuozzo.com>
> 
> Add separate "Command flags" section to make it clear which flags are
> currently defined by the protocol.
> 
> Signed-off-by: Pavel Borzenkov <pborzenkov@virtuozzo.com>
> Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
> Signed-off-by: Denis V. Lunev <den@openvz.org>
> CC: Wouter Verhelst <w@uter.be>
> CC: Eric Blake <eblake@redhat.com>
> CC: Alex Bligh <alex@alex.org.uk>
> ---
>  doc/proto.md | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/doc/proto.md b/doc/proto.md
> index 036d6d9..662f741 100644
> --- a/doc/proto.md
> +++ b/doc/proto.md
> @@ -485,6 +485,16 @@ The following request types exist:
>      Currently one such message is known: `NBD_CMD_CACHE`, with type set to
>      5, implemented by xnbd.
>  
> +#### Command flags
> +
> +This field of 16 bits is sent by the client with every request and provides
> +additional information to the server to execute the command. Refer to
> +aforementioned "Request types" section for information about the flags

Maybe:

s/aforementioned "Request types" section/the "Request types" section above/

> +supported by particular commands.
> +
> +- bit 0, `NBD_CMD_FLAG_FUA`; should be set to 1 if the client requires
> +  "Force Unit Access" mode of operation

Trailing dot?  Should you also mention which command(s) it is valid
with? (NBD_CMD_WRITE for now, until other extension commands are added)
 It might also be worth mentioning that the flag should not be sent
unless export flags included NBD_FLAG_SEND_FUA.

> +
>  #### Error values
>  
>  The error values are used for the error field in the reply message.
> 

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