Minor fixes to shim panic log & create task functions

cmd/containerd-shim-runhcs-v1/delete.go

@@ -40,6 +40,15 @@ The delete command will be executed in the container's bundle as its cwd.
 			return errors.New("bundle is required")
 		}
 
+		// hcsshim shim writes panic logs in the bundle directory in a file named "panic.log"
+		// log those messages (if any) on stderr so that it shows up in containerd's log.
+		// This should be done as the first thing so that we don't miss any panic logs even if
+		// something goes wrong during delete op.
+		logs, err := ioutil.ReadFile(filepath.Join(bundleFlag, "panic.log"))
+		if err == nil && len(logs) > 0 {
+			logrus.WithField("log", string(logs)).Error("found shim panic logs during delete")
+		}
+
 		// Attempt to find the hcssystem for this bundle and terminate it.
 		if sys, _ := hcs.OpenComputeSystem(ctx, idFlag); sys != nil {
 			defer sys.Close()
@@ -82,13 +91,6 @@ The delete command will be executed in the container's bundle as its cwd.
 			}
 		}
 
-		// hcsshim shim writes panic logs in the bundle directory in a file named "panic.log"
-		// log those messages (if any) on stderr so that it shows up in containerd's log.
-		logs, err := ioutil.ReadFile(filepath.Join(bundleFlag, "panic.log"))
-		if err == nil && len(logs) > 0 {
-			logrus.WithField("log", string(logs)).Error("found shim panic logs during delete")
-		}
-
 		// Remove the bundle on disk
 		if err := os.RemoveAll(bundleFlag); err != nil && !os.IsNotExist(err) {
 			return err

cmd/containerd-shim-runhcs-v1/pod.go

@@ -232,10 +232,6 @@ type pod struct {
 	// It MUST be treated as read only in the lifetime of the pod.
 	host *uvm.UtilityVM
 
-	// wcl is the workload create mutex. All calls to CreateTask must hold this
-	// lock while the ID reservation takes place. Once the ID is held it is safe
-	// to release the lock to allow concurrent creates.
-	wcl           sync.Mutex
 	workloadTasks sync.Map
 }
 
@@ -262,17 +258,10 @@ func (p *pod) CreateTask(ctx context.Context, req *task.CreateTaskRequest, s *sp
 		return nil, errors.Wrapf(errdefs.ErrFailedPrecondition, "task with id: '%s' cannot be created in pod: '%s' which is not running", req.ID, p.id)
 	}
 
-	p.wcl.Lock()
-	_, loaded := p.workloadTasks.LoadOrStore(req.ID, nil)
-	if loaded {
+	_, ok := p.workloadTasks.Load(req.ID)
+	if ok {
 		return nil, errors.Wrapf(errdefs.ErrAlreadyExists, "task with id: '%s' already exists id pod: '%s'", req.ID, p.id)
 	}
-	p.wcl.Unlock()
-	defer func() {
-		if err != nil {
-			p.workloadTasks.Delete(req.ID)
-		}
-	}()
 
 	ct, sid, err := oci.GetSandboxTypeAndID(s.Annotations)
 	if err != nil {