volume/fc: fix FibreChannel volume plugin matching wrong disks

Before:
  findDisk()
    fcPathExp := "^(pci-.*-fc|fc)-0x" + wwn + "-lun-" + lun
After:
  findDisk()
    fcPathExp := "^(pci-.*-fc|fc)-0x" + wwn + "-lun-" + lun + "$"

fc path may have the same wwns but different luns.for example:
pci-0000:41:00.0-fc-0x500a0981891b8dc5-lun-1
pci-0000:41:00.0-fc-0x500a0981891b8dc5-lun-12

Function findDisk() may mismatch the fc path, return the wrong device and wrong associated devicemapper parent.
This may cause a disater that pods attach wrong disks. Accutally it happended in my testing environment before.

pkg/volume/fc/fc_util.go

@@ -62,7 +62,7 @@ func (handler *osIOHandler) WriteFile(filename string, data []byte, perm os.File
 
 // given a wwn and lun, find the device and associated devicemapper parent
 func findDisk(wwn, lun string, io ioHandler, deviceUtil volumeutil.DeviceUtil) (string, string) {
-	fcPathExp := "^(pci-.*-fc|fc)-0x" + wwn + "-lun-" + lun
+	fcPathExp := "^(pci-.*-fc|fc)-0x" + wwn + "-lun-" + lun + "$"
 	r := regexp.MustCompile(fcPathExp)
 	devPath := byPath
 	if dirs, err := io.ReadDir(devPath); err == nil {
@@ -71,7 +71,7 @@ func findDisk(wwn, lun string, io ioHandler, deviceUtil volumeutil.DeviceUtil) (
 			if r.MatchString(name) {
 				if disk, err1 := io.EvalSymlinks(devPath + name); err1 == nil {
 					dm := deviceUtil.FindMultipathDeviceForDevice(disk)
-					klog.Infof("fc: find disk: %v, dm: %v", disk, dm)
+					klog.Infof("fc: find disk: %v, dm: %v, fc path: %v", disk, dm, name)
 					return disk, dm
 				}
 			}

pkg/volume/fc/fc_util_test.go

@@ -66,7 +66,16 @@ func (handler *fakeIOHandler) ReadDir(dirname string) ([]os.FileInfo, error) {
 		f3 := &fakeFileInfo{
 			name: "abc-0000:41:00.0-fc-0x5005076810213404-lun-0",
 		}
-		return []os.FileInfo{f1, f2, f3}, nil
+		f4 := &fakeFileInfo{
+			name: "pci-0000:41:00.0-fc-0x500a0981891b8dc5-lun-12",
+		}
+		f5 := &fakeFileInfo{
+			name: "pci-0000:41:00.0-fc-0x500a0981891b8dc5-lun-1",
+		}
+		f6 := &fakeFileInfo{
+			name: "fc-0x5005076810213b32-lun-25",
+		}
+		return []os.FileInfo{f4, f5, f6, f1, f2, f3}, nil
 	case "/sys/block/":
 		f := &fakeFileInfo{
 			name: "dm-1",
@@ -86,7 +95,21 @@ func (handler *fakeIOHandler) Lstat(name string) (os.FileInfo, error) {
 }
 
 func (handler *fakeIOHandler) EvalSymlinks(path string) (string, error) {
-	return "/dev/sda", nil
+	switch path {
+	case "/dev/disk/by-path/pci-0000:41:00.0-fc-0x500a0981891b8dc5-lun-0":
+		return "/dev/sda", nil
+	case "/dev/disk/by-path/pci-0000:41:00.0-fc-0x500a0981891b8dc5-lun-1":
+		return "/dev/sdb", nil
+	case "/dev/disk/by-path/fc-0x5005076810213b32-lun-2":
+		return "/dev/sdc", nil
+	case "/dev/disk/by-path/pci-0000:41:00.0-fc-0x500a0981891b8dc5-lun-12":
+		return "/dev/sdl", nil
+	case "/dev/disk/by-path/fc-0x5005076810213b32-lun-25":
+		return "/dev/sdx", nil
+	case "/dev/disk/by-id/scsi-3600508b400105e210000900000490000":
+		return "/dev/sdd", nil
+	}
+	return "", nil
 }
 
 func (handler *fakeIOHandler) WriteFile(filename string, data []byte, perm os.FileMode) error {
@@ -98,17 +121,26 @@ func TestSearchDisk(t *testing.T) {
 		name        string
 		wwns        []string
 		lun         string
+		disk        string
 		expectError bool
 	}{
 		{
-			name: "PCI disk",
+			name: "PCI disk 0",
 			wwns: []string{"500a0981891b8dc5"},
 			lun:  "0",
+			disk: "/dev/sda",
+		},
+		{
+			name: "PCI disk 1",
+			wwns: []string{"500a0981891b8dc5"},
+			lun:  "1",
+			disk: "/dev/sdb",
 		},
 		{
 			name: "Non PCI disk",
 			wwns: []string{"5005076810213b32"},
 			lun:  "2",
+			disk: "/dev/sdc",
 		},
 		{
 			name:        "Invalid Storage Controller",
@@ -145,6 +177,9 @@ func TestSearchDisk(t *testing.T) {
 			if devicePath == "" && !test.expectError {
 				t.Errorf("no fc disk found")
 			}
+			if devicePath != test.disk {
+				t.Errorf("matching wrong disk, expected: %s, actual: %s", test.disk, devicePath)
+			}
 		})
 	}
 }