[ 3.8.y.z extended stable ] Patch "drbd: fix for deadlock when using automatic split-brain-recovery" has been added to staging queue

[Kamal Mostafa]

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

    drbd: fix for deadlock when using automatic split-brain-recovery

to the linux-3.8.y-queue branch of the 3.8.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-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.2.

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

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 938c15f67c9e4abdddcf3b6798ec9f7379f9b2b6 Mon Sep 17 00:00:00 2001
From: Philipp Reisner <philipp.reisner at linbit.com>
Date: Wed, 27 Mar 2013 14:08:47 +0100
Subject: drbd: fix for deadlock when using automatic split-brain-recovery

commit 7c689e63a847316c1b2500f86891b0a574ce7e69 upstream.

With an automatic after split-brain recovery policy of
"after-sb-1pri call-pri-lost-after-sb",
when trying to drbd_set_role() to R_SECONDARY,
we run into a deadlock.

This was first recognized and supposedly fixed by
2009-06-10 "Fixed a deadlock when using automatic split brain recovery when both nodes are"
replacing drbd_set_role() with drbd_change_state() in that code-path,
but the first hunk of that patch forgets to remove the drbd_set_role().

We apparently only ever tested the "two primaries" case.

Signed-off-by: Philipp Reisner <philipp.reisner at linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg at linbit.com>
Signed-off-by: Jens Axboe <axboe at kernel.dk>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/block/drbd/drbd_receiver.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 6e27dde..2f5fffd 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2661,7 +2661,6 @@ static int drbd_asb_recover_1p(struct drbd_conf *mdev) __must_hold(local)
 		if (hg == -1 && mdev->state.role == R_PRIMARY) {
 			enum drbd_state_rv rv2;

-			drbd_set_role(mdev, R_SECONDARY, 0);
 			 /* drbd_change_state() does not sleep while in SS_IN_TRANSIENT_STATE,
 			  * we might be here in C_WF_REPORT_PARAMS which is transient.
 			  * we do not need to wait for the after state change work either. */
--
1.8.1.2