@@ -43,7 +43,7 @@ import (

 const InitProcessName = "init"

 type container struct {

-	sync.Mutex

+	mu sync.Mutex

 	bundleDir string

 	ctr       containerd.Container

@@ -52,6 +52,54 @@ type container struct {

 	oomKilled bool

 }

+func (c *container) setTask(t containerd.Task) {

+	c.mu.Lock()

+	c.task = t

+	c.mu.Unlock()

+}

+

+func (c *container) getTask() containerd.Task {

+	c.mu.Lock()

+	t := c.task

+	c.mu.Unlock()

+	return t

+}

+

+func (c *container) addProcess(id string, p containerd.Process) {

+	c.mu.Lock()

+	if c.execs == nil {

+		c.execs = make(map[string]containerd.Process)

+	}

+	c.execs[id] = p

+	c.mu.Unlock()

+}

+

+func (c *container) deleteProcess(id string) {

+	c.mu.Lock()

+	delete(c.execs, id)

+	c.mu.Unlock()

+}

+

+func (c *container) getProcess(id string) containerd.Process {

+	c.mu.Lock()

+	p := c.execs[id]

+	c.mu.Unlock()

+	return p

+}

+

+func (c *container) setOOMKilled(killed bool) {

+	c.mu.Lock()

+	c.oomKilled = killed

+	c.mu.Unlock()

+}

+

+func (c *container) getOOMKilled() bool {

+	c.mu.Lock()

+	killed := c.oomKilled

+	c.mu.Unlock()

+	return killed

+}

+

 type client struct {

 	sync.RWMutex // protects containers map

@@ -161,10 +209,10 @@ func (c *client) Create(ctx context.Context, id string, ociSpec *specs.Spec, run

 // Start create and start a task for the specified containerd id

 func (c *client) Start(ctx context.Context, id, checkpointDir string, withStdin bool, attachStdio StdioCallback) (int, error) {

 	ctr := c.getContainer(id)

-	switch {

-	case ctr == nil:

+	if ctr == nil {

 		return -1, errors.WithStack(newNotFoundError("no such container"))

-	case ctr.task != nil:

+	}

+	if t := ctr.getTask(); t != nil {

 		return -1, errors.WithStack(newConflictError("container already started"))

 	}

@@ -228,9 +276,7 @@ func (c *client) Start(ctx context.Context, id, checkpointDir string, withStdin

 		return -1, err

 	}

-	c.Lock()

-	c.containers[id].task = t

-	c.Unlock()

+	ctr.setTask(t)

 	// Signal c.createIO that it can call CloseIO

 	close(stdinCloseSync)

@@ -240,9 +286,7 @@ func (c *client) Start(ctx context.Context, id, checkpointDir string, withStdin

 			c.logger.WithError(err).WithField("container", id).

 				Error("failed to delete task after fail start")

 		}

-		c.Lock()

-		c.containers[id].task = nil

-		c.Unlock()

+		ctr.setTask(nil)

 		return -1, err

 	}

@@ -251,12 +295,15 @@ func (c *client) Start(ctx context.Context, id, checkpointDir string, withStdin

 func (c *client) Exec(ctx context.Context, containerID, processID string, spec *specs.Process, withStdin bool, attachStdio StdioCallback) (int, error) {

 	ctr := c.getContainer(containerID)

-	switch {

-	case ctr == nil:

+	if ctr == nil {

 		return -1, errors.WithStack(newNotFoundError("no such container"))

-	case ctr.task == nil:

+	}

+	t := ctr.getTask()

+	if t == nil {

 		return -1, errors.WithStack(newInvalidParameterError("container is not running"))

-	case ctr.execs != nil && ctr.execs[processID] != nil:

+	}

+

+	if p := ctr.getProcess(processID); p != nil {

 		return -1, errors.WithStack(newConflictError("id already in use"))

 	}

@@ -279,7 +326,7 @@ func (c *client) Exec(ctx context.Context, containerID, processID string, spec *

 		}

 	}()

-	p, err = ctr.task.Exec(ctx, processID, spec, func(id string) (cio.IO, error) {

+	p, err = t.Exec(ctx, processID, spec, func(id string) (cio.IO, error) {

 		rio, err = c.createIO(fifos, containerID, processID, stdinCloseSync, attachStdio)

 		return rio, err

 	})

@@ -292,21 +339,14 @@ func (c *client) Exec(ctx context.Context, containerID, processID string, spec *

 		return -1, err

 	}

-	ctr.Lock()

-	if ctr.execs == nil {

-		ctr.execs = make(map[string]containerd.Process)

-	}

-	ctr.execs[processID] = p

-	ctr.Unlock()

+	ctr.addProcess(processID, p)

 	// Signal c.createIO that it can call CloseIO

 	close(stdinCloseSync)

 	if err = p.Start(ctx); err != nil {

 		p.Delete(context.Background())

-		ctr.Lock()

-		delete(ctr.execs, processID)

-		ctr.Unlock()

+		ctr.deleteProcess(processID)

 		return -1, err

 	}

@@ -432,12 +472,9 @@ func (c *client) DeleteTask(ctx context.Context, containerID string) (uint32, ti

 		return 255, time.Now(), nil

 	}

-	c.Lock()

-	if ctr, ok := c.containers[containerID]; ok {

-		ctr.task = nil

+	if ctr := c.getContainer(containerID); ctr != nil {

+		ctr.setTask(nil)

 	}

-	c.Unlock()

-

 	return status.ExitCode(), status.ExitTime(), nil

 }

@@ -471,7 +508,12 @@ func (c *client) Status(ctx context.Context, containerID string) (Status, error)

 		return StatusUnknown, errors.WithStack(newNotFoundError("no such container"))

 	}

-	s, err := ctr.task.Status(ctx)

+	t := ctr.getTask()

+	if t == nil {

+		return StatusUnknown, errors.WithStack(newNotFoundError("no such task"))

+	}

+

+	s, err := t.Status(ctx)

 	if err != nil {

 		return StatusUnknown, err

 	}

@@ -547,26 +589,22 @@ func (c *client) removeContainer(id string) {

 func (c *client) getProcess(containerID, processID string) (containerd.Process, error) {

 	ctr := c.getContainer(containerID)

-	switch {

-	case ctr == nil:

+	if ctr == nil {

 		return nil, errors.WithStack(newNotFoundError("no such container"))

-	case ctr.task == nil:

+	}

+

+	t := ctr.getTask()

+	if t == nil {

 		return nil, errors.WithStack(newNotFoundError("container is not running"))

-	case processID == InitProcessName:

-		return ctr.task, nil

-	default:

-		ctr.Lock()

-		defer ctr.Unlock()

-		if ctr.execs == nil {

-			return nil, errors.WithStack(newNotFoundError("no execs"))

-		}

+	}

+	if processID == InitProcessName {

+		return t, nil

 	}

-	p := ctr.execs[processID]

+	p := ctr.getProcess(processID)

 	if p == nil {

 		return nil, errors.WithStack(newNotFoundError("no such exec"))

 	}

-

 	return p, nil

 }

@@ -624,12 +662,7 @@ func (c *client) processEvent(ctr *container, et EventType, ei EventInfo) {

 		}

 		if et == EventExit && ei.ProcessID != ei.ContainerID {

-			var p containerd.Process

-			ctr.Lock()

-			if ctr.execs != nil {

-				p = ctr.execs[ei.ProcessID]

-			}

-			ctr.Unlock()

+			p := ctr.getProcess(ei.ProcessID)

 			if p == nil {

 				c.logger.WithError(errors.New("no such process")).

 					WithFields(logrus.Fields{

@@ -645,9 +678,8 @@ func (c *client) processEvent(ctr *container, et EventType, ei EventInfo) {

 					"process":   ei.ProcessID,

 				}).Warn("failed to delete process")

 			}

-			c.Lock()

-			delete(ctr.execs, ei.ProcessID)

-			c.Unlock()

+			ctr.deleteProcess(ei.ProcessID)

+

 			ctr := c.getContainer(ei.ContainerID)

 			if ctr == nil {

 				c.logger.WithFields(logrus.Fields{

@@ -784,10 +816,10 @@ func (c *client) processEventStream(ctx context.Context) {

 		}

 		if oomKilled {

-			ctr.oomKilled = true

+			ctr.setOOMKilled(true)

 			oomKilled = false

 		}

-		ei.OOMKilled = ctr.oomKilled

+		ei.OOMKilled = ctr.getOOMKilled()

 		c.processEvent(ctr, et, ei)

 	}