drbd: Fixed removal of volumes/devices from connected resources

When removing a volume/device we need to switch the connection
status of the peer back into WFReportParams.

  Before this fix it was left in Connected state. That means that
  the peer device continued to inform us about state changes, etc...
  But we deleted that minor -> protocol error.

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

drivers/block/drbd/drbd_nl.c

@@ -3061,6 +3061,8 @@ static enum drbd_ret_code adm_delete_minor(struct drbd_conf *mdev)
 	     * we may want to delete a minor from a live replication group.
 	     */
 	    mdev->state.role == R_SECONDARY) {
+		_drbd_request_state(mdev, NS(conn, C_WF_REPORT_PARAMS),
+				    CS_VERBOSE + CS_WAIT_COMPLETE);
 		idr_remove(&mdev->tconn->volumes, mdev->vnr);
 		idr_remove(&minors, mdev_to_minor(mdev));
 		del_gendisk(mdev->vdisk);

drivers/block/drbd/drbd_receiver.c

@@ -3628,6 +3628,7 @@ static union drbd_state convert_state(union drbd_state ps)
 	union drbd_state ms;
 
 	static enum drbd_conns c_tab[] = {
+		[C_WF_REPORT_PARAMS] = C_WF_REPORT_PARAMS,
 		[C_CONNECTED] = C_CONNECTED,
 
 		[C_STARTING_SYNC_S] = C_STARTING_SYNC_T,

drivers/block/drbd/drbd_state.c

@@ -201,7 +201,8 @@ static int cl_wide_st_chg(struct drbd_conf *mdev,
 		  (os.conn != C_STARTING_SYNC_S && ns.conn == C_STARTING_SYNC_S) ||
 		  (os.disk != D_DISKLESS && ns.disk == D_DISKLESS))) ||
 		(os.conn >= C_CONNECTED && ns.conn == C_DISCONNECTING) ||
-		(os.conn == C_CONNECTED && ns.conn == C_VERIFY_S);
+		(os.conn == C_CONNECTED && ns.conn == C_VERIFY_S) ||
+		(os.conn == C_CONNECTED && ns.conn == C_WF_REPORT_PARAMS);
 }
 
 static union drbd_state
@@ -1202,7 +1203,8 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
 	}
 
 	/* Do not change the order of the if above and the two below... */
-	if (os.pdsk == D_DISKLESS && ns.pdsk > D_DISKLESS) {      /* attach on the peer */
+	if (os.pdsk == D_DISKLESS &&
+	    ns.pdsk > D_DISKLESS && ns.pdsk != D_UNKNOWN) {      /* attach on the peer */
 		drbd_send_uuids(mdev);
 		drbd_send_state(mdev);
 	}