[3.13.y.z extended stable] Patch "NFSv4: Fix another bug in the close/open_downgrade code" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    NFSv4: Fix another bug in the close/open_downgrade code

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.9.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 48a0832c0fa21eccc5009cdc04b6dac3c80954dc Mon Sep 17 00:00:00 2001
From: Trond Myklebust <trond.myklebust at primarydata.com>
Date: Thu, 18 Sep 2014 11:51:32 -0400
Subject: NFSv4: Fix another bug in the close/open_downgrade code

commit cd9288ffaea4359d5cfe2b8d264911506aed26a4 upstream.

James Drew reports another bug whereby the NFS client is now sending
an OPEN_DOWNGRADE in a situation where it should really have sent a
CLOSE: the client is opening the file for O_RDWR, but then trying to
do a downgrade to O_RDONLY, which is not allowed by the NFSv4 spec.

Reported-by: James Drews <drews at engr.wisc.edu>
Link: http://lkml.kernel.org/r/541AD7E5.8020409@engr.wisc.edu
Fixes: aee7af356e15 (NFSv4: Fix problems with close in the presence...)
Signed-off-by: Trond Myklebust <trond.myklebust at primarydata.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 fs/nfs/nfs4proc.c | 30 +++++++++++++++---------------
 1 file changed, 15 insertions(+), 15 deletions(-)

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 663ab1d..b6ed520 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2557,23 +2557,23 @@ static void nfs4_close_prepare(struct rpc_task *task, void *data)
 	is_rdwr = test_bit(NFS_O_RDWR_STATE, &state->flags);
 	is_rdonly = test_bit(NFS_O_RDONLY_STATE, &state->flags);
 	is_wronly = test_bit(NFS_O_WRONLY_STATE, &state->flags);
-	/* Calculate the current open share mode */
-	calldata->arg.fmode = 0;
-	if (is_rdonly || is_rdwr)
-		calldata->arg.fmode |= FMODE_READ;
-	if (is_wronly || is_rdwr)
-		calldata->arg.fmode |= FMODE_WRITE;
 	/* Calculate the change in open mode */
+	calldata->arg.fmode = 0;
 	if (state->n_rdwr == 0) {
-		if (state->n_rdonly == 0) {
-			call_close |= is_rdonly || is_rdwr;
-			calldata->arg.fmode &= ~FMODE_READ;
-		}
-		if (state->n_wronly == 0) {
-			call_close |= is_wronly || is_rdwr;
-			calldata->arg.fmode &= ~FMODE_WRITE;
-		}
-	}
+		if (state->n_rdonly == 0)
+			call_close |= is_rdonly;
+		else if (is_rdonly)
+			calldata->arg.fmode |= FMODE_READ;
+		if (state->n_wronly == 0)
+			call_close |= is_wronly;
+		else if (is_wronly)
+			calldata->arg.fmode |= FMODE_WRITE;
+	} else if (is_rdwr)
+		calldata->arg.fmode |= FMODE_READ|FMODE_WRITE;
+
+	if (calldata->arg.fmode == 0)
+		call_close |= is_rdwr;
+
 	if (!nfs4_valid_open_stateid(state))
 		call_close = 0;
 	spin_unlock(&state->owner->so_lock);
--
1.9.1