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, these
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 #351

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

device.go

@@ -216,16 +216,28 @@ 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
 
+			// Resources MUST BE updated since they are used to identify the
+			// device in the devices cgrup
+			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
 		}
 	}