endpoint_cnt store updates should not create an object

endpoint_cnt object is created during network create and destroyed when
network is deleted. But the updateToStore function creates an object
when it is not present in the store. endpoint_cnt is a mutable object
and is updated during endpoint create and delete events. If endpoint
create or delete happens after the network is deleted, it can
incorrectly create an endpoint_cnt object in the store and that can
cause problems when the same network is created again later.

The fix is to not create the endpoint_cnt object when endpoint_cnt is
incremented or decremented

Signed-off-by: Madhu Venugopal <madhu@docker.com>

libnetwork/endpoint_cnt.go

@@ -138,6 +138,15 @@ func (ec *endpointCnt) setCnt(cnt uint64) error {
 }
 
 func (ec *endpointCnt) atomicIncDecEpCnt(inc bool) error {
+	store := ec.n.getController().getStore(ec.DataScope())
+	if store == nil {
+		return fmt.Errorf("store not found for scope %s", ec.DataScope())
+	}
+
+	tmp := &endpointCnt{n: ec.n}
+	if err := store.GetObject(datastore.Key(ec.Key()...), tmp); err != nil {
+		return err
+	}
 retry:
 	ec.Lock()
 	if inc {
@@ -149,11 +158,6 @@ retry:
 	}
 	ec.Unlock()
 
-	store := ec.n.getController().getStore(ec.DataScope())
-	if store == nil {
-		return fmt.Errorf("store not found for scope %s", ec.DataScope())
-	}
-
 	if err := ec.n.getController().updateToStore(ec); err != nil {
 		if err == datastore.ErrKeyModified {
 			if err := store.GetObject(datastore.Key(ec.Key()...), ec); err != nil {

libnetwork/store.go

@@ -256,6 +256,7 @@ retry:
 			if err := cs.GetObject(datastore.Key(kvObject.Key()...), kvObject); err != nil {
 				return fmt.Errorf("could not update the kvobject to latest when trying to delete: %v", err)
 			}
+			logrus.Errorf("Error (%v) deleting object %v, retrying....", err, kvObject.Key())
 			goto retry
 		}
 		return err