From f2d7195ca0a794b5822f991b5cba78032ccf0f7c Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust@primarydata.com>
Date: Sat, 25 Jun 2016 19:19:28 -0400
Subject: [PATCH] NFS: Fix another OPEN_DOWNGRADE bug

commit e547f2628327fec6afd2e03b46f113f614cca05b upstream.

Olga Kornievskaia reports that the following test fails to trigger
an OPEN_DOWNGRADE on the wire, and only triggers the final CLOSE.

	fd0 = open(foo, RDRW)   -- should be open on the wire for "both"
	fd1 = open(foo, RDONLY)  -- should be open on the wire for "read"
	close(fd0) -- should trigger an open_downgrade
	read(fd1)
	close(fd1)

The issue is that we're missing a check for whether or not the current
state transitioned from an O_RDWR state as opposed to having transitioned
from a combination of O_RDONLY and O_WRONLY.

Reported-by: Olga Kornievskaia <aglo@umich.edu>
Fixes: cd9288ffaea4 ("NFSv4: Fix another bug in the close/open_downgrade code")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
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