[Qemu-devel] [PATCH 3/3] NBD proto: add "Command flags" section

["Denis V. Lunev" <den@openvz.org>]

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
+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
+
 #### Error values
 
 The error values are used for the error field in the reply message.
-- 
2.1.4