drbd: Fix a potential issue with the DISCARD_CONCURRENT flag

The DISCARD_CONCURRENT flag should be set on one node and cleared on the
other node.
As the code was before it was theoretical possible that a node accepts the
meta socket, but has to close it later on, and keeps the DISCARD_CONCURRENT
flag.
Correct this by moving the clear_bit(DISCARD_CONCURRENT) where the packet
gets sent.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/drbd/drbd_receiver.c

@@ -763,8 +763,6 @@ static int drbd_connect(struct drbd_conf *mdev)
 	if (drbd_request_state(mdev, NS(conn, C_WF_CONNECTION)) < SS_SUCCESS)
 		return -2;
 
-	clear_bit(DISCARD_CONCURRENT, &mdev->flags);
-
 	sock  = NULL;
 	msock = NULL;
 
@@ -784,6 +782,7 @@ static int drbd_connect(struct drbd_conf *mdev)
 				sock = s;
 				s = NULL;
 			} else if (!msock) {
+				clear_bit(DISCARD_CONCURRENT, &mdev->flags);
 				drbd_send_fp(mdev, s, P_HAND_SHAKE_M);
 				msock = s;
 				s = NULL;