Net operations already hold locks to containers

Fix a deadlock caused by re-entrant locks on container objects.

Signed-off-by: Fabio Kung <fabio.kung@gmail.com>

daemon/container_operations.go

@@ -45,16 +45,6 @@ func (daemon *Daemon) getDNSSearchSettings(container *container.Container) []str
 	return nil
 }
 
-// checkpointAndSave grabs a container lock to safely call container.CheckpointTo
-func (daemon *Daemon) checkpointAndSave(container *container.Container) error {
-	container.Lock()
-	defer container.Unlock()
-	if err := container.CheckpointTo(daemon.containersReplica); err != nil {
-		return fmt.Errorf("Error saving container state: %v", err)
-	}
-	return nil
-}
-
 func (daemon *Daemon) buildSandboxOptions(container *container.Container) ([]libnetwork.SandboxOption, error) {
 	var (
 		sboxOptions []libnetwork.SandboxOption
@@ -1017,7 +1007,7 @@ func (daemon *Daemon) ConnectToNetwork(container *container.Container, idOrName
 		}
 	}
 
-	return daemon.checkpointAndSave(container)
+	return container.CheckpointTo(daemon.containersReplica)
 }
 
 // DisconnectFromNetwork disconnects container from network n.
@@ -1053,7 +1043,7 @@ func (daemon *Daemon) DisconnectFromNetwork(container *container.Container, netw
 		return err
 	}
 
-	if err := daemon.checkpointAndSave(container); err != nil {
+	if err := container.CheckpointTo(daemon.containersReplica); err != nil {
 		return err
 	}
 

daemon/daemon.go

@@ -1233,3 +1233,13 @@ func CreateDaemonRoot(config *config.Config) error {
 	}
 	return setupDaemonRoot(config, realRoot, idMappings.RootPair())
 }
+
+// checkpointAndSave grabs a container lock to safely call container.CheckpointTo
+func (daemon *Daemon) checkpointAndSave(container *container.Container) error {
+	container.Lock()
+	defer container.Unlock()
+	if err := container.CheckpointTo(daemon.containersReplica); err != nil {
+		return fmt.Errorf("Error saving container state: %v", err)
+	}
+	return nil
+}