drbd: When proxy's buffer drained off go into regular resync mode

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

drivers/block/drbd/drbd_int.h

@@ -973,7 +973,8 @@ struct drbd_conf {
 	struct drbd_work  resync_work,
 			  unplug_work,
 			  go_diskless,
-			  md_sync_work;
+			  md_sync_work,
+			  start_resync_work;
 	struct timer_list resync_timer;
 	struct timer_list md_sync_timer;
 #ifdef DRBD_DEBUG_MD_SYNC
@@ -1546,6 +1547,7 @@ extern int w_prev_work_done(struct drbd_conf *, struct drbd_work *, int);
 extern int w_e_reissue(struct drbd_conf *, struct drbd_work *, int);
 extern int w_restart_disk_io(struct drbd_conf *, struct drbd_work *, int);
 extern int w_send_oos(struct drbd_conf *, struct drbd_work *, int);
+extern int w_start_resync(struct drbd_conf *, struct drbd_work *, int);
 
 extern void resync_timer_fn(unsigned long data);
 

drivers/block/drbd/drbd_main.c

@@ -2846,6 +2846,7 @@ void drbd_init_set_defaults(struct drbd_conf *mdev)
 	INIT_LIST_HEAD(&mdev->unplug_work.list);
 	INIT_LIST_HEAD(&mdev->go_diskless.list);
 	INIT_LIST_HEAD(&mdev->md_sync_work.list);
+	INIT_LIST_HEAD(&mdev->start_resync_work.list);
 	INIT_LIST_HEAD(&mdev->bm_io_work.w.list);
 
 	mdev->resync_work.cb  = w_resync_inactive;

drivers/block/drbd/drbd_receiver.c

@@ -3279,6 +3279,7 @@ static int receive_sync_uuid(struct drbd_conf *mdev, enum drbd_packets cmd, unsi
 
 	wait_event(mdev->misc_wait,
 		   mdev->state.conn == C_WF_SYNC_UUID ||
+		   mdev->state.conn == C_BEHIND ||
 		   mdev->state.conn < C_CONNECTED ||
 		   mdev->state.disk < D_NEGOTIATING);
 
@@ -4338,6 +4339,14 @@ static int got_BarrierAck(struct drbd_conf *mdev, struct p_header80 *h)
 
 	tl_release(mdev, p->barrier, be32_to_cpu(p->set_size));
 
+	if (mdev->state.conn == C_AHEAD &&
+	    atomic_read(&mdev->ap_in_flight) == 0 &&
+	    list_empty(&mdev->start_resync_work.list)) {
+		    struct drbd_work *w = &mdev->start_resync_work;
+		    w->cb = w_start_resync;
+		    drbd_queue_work_front(&mdev->data.work, w);
+	}
+
 	return TRUE;
 }
 

drivers/block/drbd/drbd_worker.c

@@ -742,6 +742,14 @@ static int w_make_ov_request(struct drbd_conf *mdev, struct drbd_work *w, int ca
 	return 1;
 }
 
+
+int w_start_resync(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+	drbd_start_resync(mdev, C_SYNC_SOURCE);
+
+	return 1;
+}
+
 int w_ov_finished(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
 {
 	kfree(w);
@@ -1472,7 +1480,7 @@ void drbd_start_resync(struct drbd_conf *mdev, enum drbd_conns side)
 	union drbd_state ns;
 	int r;
 
-	if (mdev->state.conn >= C_SYNC_SOURCE) {
+	if (mdev->state.conn >= C_SYNC_SOURCE && mdev->state.conn < C_AHEAD) {
 		dev_err(DEV, "Resync already running!\n");
 		return;
 	}