[ 43/50] drbd: fix for deadlock when using automatic split-brain-recovery

From: Greg Kroah-Hartman
Date: Fri May 17 2013 - 17:49:54 EST

3.4-stable review patch. If anyone has any objections, please let me know.


From: Philipp Reisner <philipp.reisner@xxxxxxxxxx>

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@xxxxxxxxxx>
Signed-off-by: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Jonghwan Choi <jhbird.choi@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/block/drbd/drbd_receiver.c | 1 -
1 file changed, 1 deletion(-)

--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -2225,7 +2225,6 @@ static int drbd_asb_recover_1p(struct dr
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. */

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