3 files changed, 39 insertions, 6 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index c194348a46ed..e9654c8d5b62 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -943,7 +943,8 @@ struct drbd_conf {
 	struct drbd_work  resync_work,
 			  unplug_work,
 			  md_sync_work,
-			  delay_probe_work;
+			  delay_probe_work,
+			  uuid_work;
 	struct timer_list resync_timer;
 	struct timer_list md_sync_timer;
 	struct timer_list delay_probe_timer;
@@ -1068,6 +1069,7 @@ struct drbd_conf {
 	struct timeval dps_time; /* delay-probes-start-time */
 	unsigned int dp_volume_last;  /* send_cnt of last delay probe */
 	int c_sync_rate; /* current resync rate after delay_probe magic */
+	atomic_t new_c_uuid;
 };
 
 static inline struct drbd_conf *minor_to_mdev(unsigned int minor)
@@ -2217,6 +2219,8 @@ static inline int __inc_ap_bio_cond(struct drbd_conf *mdev)
 		return 0;
 	if (test_bit(BITMAP_IO, &mdev->flags))
 		return 0;
+	if (atomic_read(&mdev->new_c_uuid))
+		return 0;
 	return 1;
 }
 
@@ -2237,6 +2241,9 @@ static inline void inc_ap_bio(struct drbd_conf *mdev, int count)
 	 * to avoid races with the reconnect code,
 	 * we need to atomic_inc within the spinlock. */
 
+	if (atomic_read(&mdev->new_c_uuid) && atomic_add_unless(&mdev->new_c_uuid, -1, 1))
+		drbd_queue_work_front(&mdev->data.work, &mdev->uuid_work);
+
 	spin_lock_irq(&mdev->req_lock);
 	while (!__inc_ap_bio_cond(mdev)) {
 		prepare_to_wait(&mdev->misc_wait, &wait, TASK_UNINTERRUPTIBLE);
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index d0fabace1452..c144509011b8 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -1217,17 +1217,16 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
 		mdev->p_uuid = NULL;
 		if (get_ldev(mdev)) {
 			if ((ns.role == R_PRIMARY || ns.peer == R_PRIMARY) &&
-			    mdev->ldev->md.uuid[UI_BITMAP] == 0 && ns.disk >= D_UP_TO_DATE) {
-				drbd_uuid_new_current(mdev);
-				drbd_send_uuids(mdev);
-			}
+			    mdev->ldev->md.uuid[UI_BITMAP] == 0 && ns.disk >= D_UP_TO_DATE)
+				atomic_set(&mdev->new_c_uuid, 2);
 			put_ldev(mdev);
 		}
 	}
 
 	if (ns.pdsk < D_INCONSISTENT && get_ldev(mdev)) {
+		/* Diskless peer becomes primary or got connected do diskless, primary peer. */
 		if (ns.peer == R_PRIMARY && mdev->ldev->md.uuid[UI_BITMAP] == 0)
-			drbd_uuid_new_current(mdev);
+			atomic_set(&mdev->new_c_uuid, 2);
 
 		/* D_DISKLESS Peer becomes secondary */
 		if (os.peer == R_PRIMARY && ns.peer == R_SECONDARY)
@@ -1351,6 +1350,19 @@ static void after_state_ch(struct drbd_conf *mdev, union drbd_state os,
 	drbd_md_sync(mdev);
 }
 
+static int w_new_current_uuid(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
+{
+	if (get_ldev(mdev)) {
+		drbd_uuid_new_current(mdev);
+		drbd_send_uuids(mdev);
+		drbd_md_sync(mdev);
+		put_ldev(mdev);
+	}
+	atomic_dec(&mdev->new_c_uuid);
+	wake_up(&mdev->misc_wait);
+
+	return 1;
+}
 
 static int drbd_thread_setup(void *arg)
 {
@@ -2691,6 +2703,7 @@ void drbd_init_set_defaults(struct drbd_conf *mdev)
 	atomic_set(&mdev->net_cnt, 0);
 	atomic_set(&mdev->packet_seq, 0);
 	atomic_set(&mdev->pp_in_use, 0);
+	atomic_set(&mdev->new_c_uuid, 0);
 
 	mutex_init(&mdev->md_io_mutex);
 	mutex_init(&mdev->data.mutex);
@@ -2721,12 +2734,14 @@ void drbd_init_set_defaults(struct drbd_conf *mdev)
 	INIT_LIST_HEAD(&mdev->bm_io_work.w.list);
 	INIT_LIST_HEAD(&mdev->delay_probes);
 	INIT_LIST_HEAD(&mdev->delay_probe_work.list);
+	INIT_LIST_HEAD(&mdev->uuid_work.list);
 
 	mdev->resync_work.cb  = w_resync_inactive;
 	mdev->unplug_work.cb  = w_send_write_hint;
 	mdev->md_sync_work.cb = w_md_sync;
 	mdev->bm_io_work.w.cb = w_bitmap_io;
 	mdev->delay_probe_work.cb = w_delay_probes;
+	mdev->uuid_work.cb = w_new_current_uuid;
 	init_timer(&mdev->resync_timer);
 	init_timer(&mdev->md_sync_timer);
 	init_timer(&mdev->delay_probe_timer);
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index a04ec01ab3ce..461d9872d4d3 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -1150,6 +1150,17 @@ int drbd_submit_ee(struct drbd_conf *mdev, struct drbd_epoch_entry *e,
 	unsigned n_bios = 0;
 	unsigned nr_pages = (ds + PAGE_SIZE -1) >> PAGE_SHIFT;
 
+	if (atomic_read(&mdev->new_c_uuid)) {
+		if (atomic_add_unless(&mdev->new_c_uuid, -1, 1)) {
+			drbd_uuid_new_current(mdev);
+			drbd_md_sync(mdev);
+
+			atomic_dec(&mdev->new_c_uuid);
+			wake_up(&mdev->misc_wait);
+		}
+		wait_event(mdev->misc_wait, !atomic_read(&mdev->new_c_uuid));
+	}
+
 	/* In most cases, we will only need one bio.  But in case the lower
 	 * level restrictions happen to be different at this offset on this
 	 * side than those of the sending peer, we may need to submit the