Trim out suffix added to backing file path of loopback device

When a block device, say /dev/sdc, is unexpectedly disconnected from a node,
the corresponding backing file path found at /sys/block/loop*/backing_file gets
a "(deleted)" suffix. This patch trims that suffix out, allowing the Kubelet to
unmount the volume correctly.

pkg/volume/util/volumepathhandler/volume_path_handler_linux.go

@@ -139,7 +139,7 @@ func getLoopDeviceFromSysfs(path string) (string, error) {
 		}
 
 		// Return the first match.
-		backingFilePath := strings.TrimSpace(string(data))
+		backingFilePath := cleanBackingFilePath(string(data))
 		if backingFilePath == path || backingFilePath == realPath {
 			return fmt.Sprintf("/dev/%s", filepath.Base(device)), nil
 		}
@@ -148,6 +148,14 @@ func getLoopDeviceFromSysfs(path string) (string, error) {
 	return "", errors.New(ErrDeviceNotFound)
 }
 
+// cleanPath remove any trailing substrings that are not part of the backing file path.
+func cleanBackingFilePath(path string) string {
+	// If the block device was deleted, the path will contain a "(deleted)" suffix
+	path = strings.TrimSpace(path)
+	path = strings.TrimSuffix(path, "(deleted)")
+	return strings.TrimSpace(path)
+}
+
 // FindGlobalMapPathUUIDFromPod finds {pod uuid} bind mount under globalMapPath
 // corresponding to map path symlink, and then return global map path with pod uuid.
 // (See pkg/volume/volume.go for details on a global map path and a pod device map path.)

pkg/volume/util/volumepathhandler/volume_path_handler_linux_test.go

@@ -0,0 +1,65 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package volumepathhandler
+
+import (
+	"fmt"
+	"testing"
+)
+
+func pathWithSuffix(suffix string) string {
+	return fmt.Sprintf("%s%s", "/var/lib/kubelet/plugins/kubernetes.io/csi/volumeDevices/pvc-1d205234-06cd-4fe4-a7ea-0e8f3e2faf5f/dev/e196ebd3-2ab1-4185-bed4-b997ba38d1dc", suffix)
+}
+
+func TestCleanBackingFilePath(t *testing.T) {
+	const defaultPath = "/var/lib/kubelet/plugins/kubernetes.io/csi/volumeDevices/pvc-1d205234-06cd-4fe4-a7ea-0e8f3e2faf5f/dev/e196ebd3-2ab1-4185-bed4-b997ba38d1dc"
+	testCases := []struct {
+		name          string
+		input         string
+		expectedOuput string
+	}{
+		{
+			name:          "regular path",
+			input:         defaultPath,
+			expectedOuput: defaultPath,
+		},
+		{
+			name:          "path is suffixed with whitespaces",
+			input:         fmt.Sprintf("%s\r\t\n ", defaultPath),
+			expectedOuput: defaultPath,
+		},
+		{
+			name:          "path is suffixed with \"(deleted)\"",
+			input:         pathWithSuffix("(deleted)"),
+			expectedOuput: defaultPath,
+		},
+		{
+			name:          "path is suffixed with \"(deleted)\" and whitespaces",
+			input:         pathWithSuffix(" (deleted)\t"),
+			expectedOuput: defaultPath,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			output := cleanBackingFilePath(tc.input)
+			if output != tc.expectedOuput {
+				t.Fatalf("expected %q, got %q", tc.expectedOuput, output)
+			}
+		})
+	}
+}