agent: update resources list with the right device major-minor number

Host device's major-minor numbers are mapped to guest major-minor numbers,
for example in the host the major-minor number for /dev/loop0p1 is 259:1,
when it's attached to the VM now the major-minor number is 8:0, this
conversion must be reflected in devices and resources lists, the first list
is used to mount the device in the container and the second one is to update
the devices cgroup.

fixes kata-containers#351

Signed-off-by: Julio Montes <julio.montes@intel.com>

device.go

@@ -216,16 +216,33 @@ func updateSpecDeviceList(device pb.Device, spec *pb.Spec) error {
 	// Update the spec
 	for idx, d := range spec.Linux.Devices {
 		if d.Path == device.ContainerPath {
+			hostMajor := spec.Linux.Devices[idx].Major
+			hostMinor := spec.Linux.Devices[idx].Minor
 			agentLog.WithFields(logrus.Fields{
 				"device-path":        device.VmPath,
-				"host-device-major":  spec.Linux.Devices[idx].Major,
-				"host-device-minor":  spec.Linux.Devices[idx].Minor,
+				"host-device-major":  hostMajor,
+				"host-device-minor":  hostMinor,
 				"guest-device-major": major,
 				"guest-device-minor": minor,
 			}).Info("updating block device major/minor into the spec")
+
 			spec.Linux.Devices[idx].Major = major
 			spec.Linux.Devices[idx].Minor = minor
 
+			// there is no resource to update
+			if spec.Linux == nil || spec.Linux.Resources == nil {
+				return nil
+			}
+
+			// Resources must be updated since they are used to identify the
+			// device in the devices cgroup.
+			for idxRsrc, dRsrc := range spec.Linux.Resources.Devices {
+				if dRsrc.Major == hostMajor && dRsrc.Minor == hostMinor {
+					spec.Linux.Resources.Devices[idxRsrc].Major = major
+					spec.Linux.Resources.Devices[idxRsrc].Minor = minor
+				}
+			}
+
 			return nil
 		}
 	}

device_test.go

@@ -373,3 +373,73 @@ func TestAddDevice(t *testing.T) {
 		}
 	}
 }
+
+func TestUpdateSpecDeviceList(t *testing.T) {
+	assert := assert.New(t)
+
+	var err error
+	spec := &pb.Spec{}
+	device := pb.Device{}
+	major := int64(7)
+	minor := int64(2)
+
+	//ContainerPath empty
+	err = updateSpecDeviceList(device, spec)
+	assert.Error(err)
+
+	device.ContainerPath = "/dev/null"
+
+	//Linux is nil
+	err = updateSpecDeviceList(device, spec)
+	assert.Error(err)
+
+	spec.Linux = &pb.Linux{}
+
+	/// Linux.Devices empty
+	err = updateSpecDeviceList(device, spec)
+	assert.Error(err)
+
+	spec.Linux.Devices = []pb.LinuxDevice{
+		{
+			Path:  "/dev/null2",
+			Major: major,
+			Minor: minor,
+		},
+	}
+
+	// VmPath empty
+	err = updateSpecDeviceList(device, spec)
+	assert.Error(err)
+
+	device.VmPath = "/dev/null"
+
+	// guest and host path are not the same
+	err = updateSpecDeviceList(device, spec)
+	assert.Error(err)
+
+	spec.Linux.Devices[0].Path = device.ContainerPath
+
+	// spec.Linux.Resources is nil
+	err = updateSpecDeviceList(device, spec)
+	assert.NoError(err)
+
+	// update both devices and cgroup lists
+	spec.Linux.Devices = []pb.LinuxDevice{
+		{
+			Path:  device.ContainerPath,
+			Major: major,
+			Minor: minor,
+		},
+	}
+	spec.Linux.Resources = &pb.LinuxResources{
+		Devices: []pb.LinuxDeviceCgroup{
+			{
+				Major: major,
+				Minor: minor,
+			},
+		},
+	}
+
+	err = updateSpecDeviceList(device, spec)
+	assert.NoError(err)
+}