[ 3.5.yuz extended stable ] Patch "libceph: recheck con state after allocating incoming" has been added to staging queue

[Herton Ronaldo Krzesinski]

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

    libceph: recheck con state after allocating incoming

to the linux-3.5.y-queue branch of the 3.5.yuz extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

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

For more information about the 3.5.yuz tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Herton

------

>From e11b559c45fb0e9b107a7d4fb5705f3f6c190d64 Mon Sep 17 00:00:00 2001
From: Sage Weil <sage at inktank.com>
Date: Mon, 30 Jul 2012 18:19:45 -0700
Subject: [PATCH 68/78] libceph: recheck con state after allocating incoming
 message

commit 6139919133377652992a5fe134e22abce3e9c25e upstream.

We drop the lock when calling the ->alloc_msg() con op, which means
we need to (a) not clobber con->in_msg without the mutex held, and (b)
we need to verify that we are still in the OPEN state when we retake
it to avoid causing any mayhem.  If the state does change, -EAGAIN
will get us back to con_work() and loop.

Signed-off-by: Sage Weil <sage at inktank.com>
Reviewed-by: Alex Elder <elder at inktank.com>
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 net/ceph/messenger.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 13b549b..b6655b1 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -2735,9 +2735,16 @@ static int ceph_con_in_msg_alloc(struct ceph_connection *con, int *skip)
 	BUG_ON(con->in_msg != NULL);

 	if (con->ops->alloc_msg) {
+		struct ceph_msg *msg;
+
 		mutex_unlock(&con->mutex);
-		con->in_msg = con->ops->alloc_msg(con, hdr, skip);
+		msg = con->ops->alloc_msg(con, hdr, skip);
 		mutex_lock(&con->mutex);
+		if (con->state != CON_STATE_OPEN) {
+			ceph_msg_put(msg);
+			return -EAGAIN;
+		}
+		con->in_msg = msg;
 		if (con->in_msg) {
 			con->in_msg->con = con->ops->get(con);
 			BUG_ON(con->in_msg->con == NULL);
--
1.7.9.5