Correctly report errors on unmounting SHM

When we fail to remove a container's SHM, that's an error, and we
need to report it as such. This may be part of our lingering
storage woes.

Also, remove MNT_DETACH. It may be another cause of the storage
removal failures.

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

libpod/boltdb_state.go

@@ -1403,11 +1403,10 @@ func (s *BoltState) AddVolume(volume *Volume) error {
 	// Volume state is allowed to not exist
 	var volStateJSON []byte
 	if volume.state != nil {
-		stateJSON, err := json.Marshal(volume.state)
+		volStateJSON, err = json.Marshal(volume.state)
 		if err != nil {
 			return errors.Wrapf(err, "error marshalling volume %s state to JSON", volume.Name())
 		}
-		volStateJSON = stateJSON
 	}
 
 	db, err := s.getDBCon()

libpod/container_internal.go

@@ -1253,10 +1253,10 @@ func (c *Container) mountStorage() (_ string, Err error) {
 					return
 				}
 				vol.lock.Lock()
-				defer vol.lock.Unlock()
 				if err := vol.unmount(false); err != nil {
 					logrus.Errorf("Error unmounting volume %s after error mounting container %s: %v", vol.Name(), c.ID(), err)
 				}
+				vol.lock.Unlock()
 			}()
 		}
 	}
@@ -1281,14 +1281,19 @@ func (c *Container) cleanupStorage() error {
 		return nil
 	}
 
+	var cleanupErr error
+
 	for _, containerMount := range c.config.Mounts {
 		if err := c.unmountSHM(containerMount); err != nil {
-			return err
+			if cleanupErr != nil {
+				logrus.Errorf("Error unmounting container %s: %v", c.ID(), cleanupErr)
+			}
+			cleanupErr = err
 		}
 	}
 
 	if c.config.Rootfs != "" {
-		return nil
+		return cleanupErr
 	}
 
 	if err := c.unmount(false); err != nil {
@@ -1298,14 +1303,14 @@ func (c *Container) cleanupStorage() error {
 		// state
 		if errors.Cause(err) == storage.ErrNotAContainer || errors.Cause(err) == storage.ErrContainerUnknown {
 			logrus.Errorf("Storage for container %s has been removed", c.ID())
-			return nil
+		} else {
+			if cleanupErr != nil {
+				logrus.Errorf("Error cleaning up container %s storage: %v", c.ID(), cleanupErr)
+			}
+			cleanupErr = err
 		}
-
-		return err
 	}
 
-	var cleanupErr error
-
 	// Request an unmount of all named volumes
 	for _, v := range c.config.NamedVolumes {
 		vol, err := c.runtime.state.Volume(v.Name)

libpod/container_internal_linux.go

@@ -49,12 +49,12 @@ func (c *Container) mountSHM(shmOptions string) error {
 }
 
 func (c *Container) unmountSHM(mount string) error {
-	if err := unix.Unmount(mount, unix.MNT_DETACH); err != nil {
+	if err := unix.Unmount(mount, 0); err != nil {
 		if err != syscall.EINVAL {
-			logrus.Warnf("container %s failed to unmount %s : %v", c.ID(), mount, err)
-		} else {
-			logrus.Debugf("container %s failed to unmount %s : %v", c.ID(), mount, err)
+			return errors.Wrapf(err, "error unmounting container %s SHM mount %s", c.ID(), mount)
 		}
+		// If it's just an EINVAL, debug logs only
+		logrus.Debugf("container %s failed to unmount %s : %v", c.ID(), mount, err)
 	}
 	return nil
 }

libpod/define/config.go

@@ -18,3 +18,7 @@ type InfoData struct {
 	Type string
 	Data map[string]interface{}
 }
+
+// VolumeDriverLocal is the "local" volume driver. It is managed by libpod
+// itself.
+const VolumeDriverLocal = "local"

libpod/runtime_volume_linux.go

@@ -44,11 +44,11 @@ func (r *Runtime) newVolume(ctx context.Context, options ...VolumeCreateOption)
 		volume.config.Name = stringid.GenerateNonCryptoID()
 	}
 	if volume.config.Driver == "" {
-		volume.config.Driver = "local"
+		volume.config.Driver = define.VolumeDriverLocal
 	}
 	volume.config.CreatedTime = time.Now()
 
-	if volume.config.Driver == "local" {
+	if volume.config.Driver == define.VolumeDriverLocal {
 		logrus.Debugf("Validating options for local driver")
 		// Validate options
 		for key := range volume.config.Options {

libpod/volume_internal.go

@@ -26,7 +26,7 @@ func (v *Volume) teardownStorage() error {
 // Volumes with options set, or a filesystem type, or a device to mount need to
 // be mounted and unmounted.
 func (v *Volume) needsMount() bool {
-	return len(v.config.Options) > 0 && v.config.Driver == "local"
+	return len(v.config.Options) > 0 && v.config.Driver == define.VolumeDriverLocal
 }
 
 // update() updates the volume state from the DB.

libpod/volume_internal_linux.go

@@ -67,7 +67,7 @@ func (v *Volume) mount() error {
 
 	errPipe, err := mountCmd.StderrPipe()
 	if err != nil {
-		return errors.Wrapf(err, "getting stderr pipe")
+		return errors.Wrapf(err, "error getting stderr pipe for mount")
 	}
 	if err := mountCmd.Start(); err != nil {
 		out, err2 := ioutil.ReadAll(errPipe)

pkg/varlinkapi/volumes.go

@@ -67,8 +67,7 @@ func (i *LibpodAPI) GetVolumes(call iopodman.VarlinkCall, args []string, all boo
 			Labels:     v.Labels(),
 			MountPoint: v.MountPoint(),
 			Name:       v.Name(),
-			// TODO change types here to be correct
-			//Options:    v.Options(),
+			Options:    v.Options(),
 		}
 		volumes = append(volumes, newVol)
 	}