add iscsi volume plugin

Signed-off-by: Huamin Chen <hchen@redhat.com>

pkg/util/mount/mount.go

@@ -76,3 +76,31 @@ func GetMountRefs(mounter Interface, mountPath string) ([]string, error) {
 	}
 	return refs, nil
 }
+
+// GetDeviceNameFromMount: given a mnt point, find the device from /proc/mounts
+// returns the device name, reference count, and error code
+func GetDeviceNameFromMount(mounter Interface, mountPath string) (string, int, error) {
+	mps, err := mounter.List()
+	if err != nil {
+		return "", 0, err
+	}
+
+	// Find the device name.
+	// FIXME if multiple devices mounted on the same mount path, only the first one is returned
+	device := ""
+	for i := range mps {
+		if mps[i].Path == mountPath {
+			device = mps[i].Device
+			break
+		}
+	}
+
+	// Find all references to the device.
+	refCount := 0
+	for i := range mps {
+		if mps[i].Device == device {
+			refCount++
+		}
+	}
+	return device, refCount, nil
+}

pkg/util/mount/mount_linux_test.go

@@ -151,3 +151,32 @@ func setEquivalent(set1, set2 []string) bool {
 	}
 	return true
 }
+
+func TestGetDeviceNameFromMount(t *testing.T) {
+	fm := &FakeMounter{
+		MountPoints: []MountPoint{
+			{Device: "/dev/disk/by-path/prefix-lun-1",
+				Path: "/mnt/111"},
+			{Device: "/dev/disk/by-path/prefix-lun-1",
+				Path: "/mnt/222"},
+		},
+	}
+
+	tests := []struct {
+		mountPath      string
+		expectedDevice string
+		expectedRefs   int
+	}{
+		{
+			"/mnt/222",
+			"/dev/disk/by-path/prefix-lun-1",
+			2,
+		},
+	}
+
+	for i, test := range tests {
+		if device, refs, err := GetDeviceNameFromMount(fm, test.mountPath); err != nil || test.expectedRefs != refs || test.expectedDevice != device {
+			t.Errorf("%d. GetDeviceNameFromMount(%s) = (%s, %d), %v; expected (%s,%d), nil", i, test.mountPath, device, refs, err, test.expectedDevice, test.expectedRefs)
+		}
+	}
+}