drbd: A fixes to the new resync speed code

* Mention P_DELAY_PROBE in the packet naming array
* Do not corrupt the mdev->data.work list in case the timer goes
  off before delay_probe_work got handled by the worker
* Do not mod_timer() twice for a single delay_probe pair
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_int.h

@@ -268,6 +268,7 @@ static inline const char *cmdname(enum drbd_packets cmd)
 		[P_CSUM_RS_REQUEST]     = "CsumRSRequest",
 		[P_RS_IS_IN_SYNC]	= "CsumRSIsInSync",
 		[P_COMPRESSED_BITMAP]   = "CBitmap",
+		[P_DELAY_PROBE]         = "DelayProbe",
 		[P_MAX_CMD]	        = NULL,
 	};
 

drivers/block/drbd/drbd_main.c

@@ -2207,9 +2207,6 @@ static int drbd_send_delay_probe(struct drbd_conf *mdev, struct drbd_socket *ds)
 	}
 	mutex_unlock(&ds->mutex);
 
-	mdev->dp_volume_last = mdev->send_cnt;
-	mod_timer(&mdev->delay_probe_timer, jiffies + mdev->sync_conf.dp_interval * HZ / 10);
-
 	return ok;
 }
 
@@ -2221,6 +2218,9 @@ static int drbd_send_delay_probes(struct drbd_conf *mdev)
 	ok = drbd_send_delay_probe(mdev, &mdev->meta);
 	ok = ok && drbd_send_delay_probe(mdev, &mdev->data);
 
+	mdev->dp_volume_last = mdev->send_cnt;
+	mod_timer(&mdev->delay_probe_timer, jiffies + mdev->sync_conf.dp_interval * HZ / 10);
+
 	return ok;
 }
 
@@ -2374,7 +2374,8 @@ static void delay_probe_timer_fn(unsigned long data)
 {
 	struct drbd_conf *mdev = (struct drbd_conf *) data;
 
-	drbd_queue_work(&mdev->data.work, &mdev->delay_probe_work);
+	if (list_empty(&mdev->delay_probe_work.list))
+		drbd_queue_work(&mdev->data.work, &mdev->delay_probe_work);
 }
 
 /* Used to send write requests