drbd: fix race when forcefully disconnecting

If a forced disconnect hits a restarting receiver right after it passed
its final "if (C_DISCONNECTING)" test in drbdd_init(), but before it was
actually restarted by drbd_thread_setup, we could be left with a
connection stuck in C_DISCONNECTING, never reaching C_STANDALONE,
which would be necessary to take it down or reconfigure it.

Move the last cleanup into w_after_conn_state_ch(), and do an additional
state change request in conn_try_disconnect(), just in case.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 1 insertions, 13 deletions

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 9c8bcce0e684..956cdda93430 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -4213,20 +4213,8 @@ static void drbd_disconnect(struct drbd_tconn *tconn)
 
         spin_unlock_irq(&tconn->req_lock);
 
-        if (oc == C_DISCONNECTING) {
-                struct net_conf *old_conf;
-
-                mutex_lock(&tconn->net_conf_update);
-                old_conf = tconn->net_conf;
-                rcu_assign_pointer(tconn->net_conf, NULL);
-                conn_free_crypto(tconn);
-                mutex_unlock(&tconn->net_conf_update);
-
-                synchronize_rcu();
-                kfree(old_conf);
-
+        if (oc == C_DISCONNECTING)
                 conn_request_state(tconn, NS(conn, C_STANDALONE), CS_VERBOSE | CS_HARD);
-        }
 }
 
 static int drbd_disconnected(int vnr, void *p, void *data)