drbd: Bugfix for the connection behavior

If we get into the C_BROKEN_PIPE cstate once, the state engine set the
thi->t_state of the receiver thread to restarting.  But with the while loop
in drbdd_init() a new connection gets established. After the call into
drbdd() returns immediately since the thi->t_state is not RUNNING.  The
restart of drbd_init() then resets thi->t_state to RUNNING.

I.e. after entering C_BROKEN_PIPE once, the next successful established
connection gets wasted.

The two parts of the fix:
  * Do not cause the thread to restart if we detect the issue
    with the sockets while we are in C_WF_CONNECTION.

  * Make sure that all actions that would have set us to C_BROKEN_PIPE
    happen before the state change to C_WF_REPORT_PARAMS.

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

2 files changed, 6 insertions, 6 deletions

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 56569a803331..8658dac2853a 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1318,7 +1318,7 @@ __drbd_set_state(struct drbd_conf *mdev, union drbd_state ns,
                 drbd_thread_stop_nowait(&mdev->receiver);
 
         /* Upon network failure, we need to restart the receiver. */
-        if (os.conn > C_TEAR_DOWN &&
+        if (os.conn > C_WF_CONNECTION &&
             ns.conn <= C_TEAR_DOWN && ns.conn >= C_TIMEOUT)
                 drbd_thread_restart_nowait(&mdev->receiver);
 
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index bb92671d1f16..aa6c52c80e2e 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -888,17 +888,12 @@ retry:
                 }
         }
 
-        if (drbd_request_state(mdev, NS(conn, C_WF_REPORT_PARAMS)) < SS_SUCCESS)
-                return 0;
-
         sock->sk->sk_sndtimeo = mdev->net_conf->timeout*HZ/10;
         sock->sk->sk_rcvtimeo = MAX_SCHEDULE_TIMEOUT;
 
         atomic_set(&mdev->packet_seq, 0);
         mdev->peer_seq = 0;
 
-        drbd_thread_start(&mdev->asender);
-
         if (drbd_send_protocol(mdev) == -1)
                 return -1;
         drbd_send_sync_param(mdev, &mdev->sync_conf);
@@ -907,6 +902,11 @@ retry:
         drbd_send_state(mdev);
         clear_bit(USE_DEGR_WFC_T, &mdev->flags);
         clear_bit(RESIZE_PENDING, &mdev->flags);
+
+        if (drbd_request_state(mdev, NS(conn, C_WF_REPORT_PARAMS)) < SS_SUCCESS)
+                return 0;
+
+        drbd_thread_start(&mdev->asender);
         mod_timer(&mdev->request_timer, jiffies + HZ); /* just start it here. */
 
         return 1;