You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: secret.go
    path of file: ./repos/kubernetes/pkg/volume/secret
    
    the code of the file until where you have to start completion: /*
Copyright 2015 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 secret

import (
	"fmt"

	"k8s.io/klog/v2"
	"k8s.io/mount-utils"
	utilstrings "k8s.io/utils/strings"

	v1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/types"
	"k8s.io/kubernetes/pkg/volume"
	volumeutil "k8s.io/kubernetes/pkg/volume/util"
)

// ProbeVolumePlugins is the entry point for plugin detection in a package.
func Pr
    
func (b *secretVolumeMounter) SetUpAt(dir string, mounterArgs volume.MounterArgs) error {
	klog.V(3).Infof("Setting up volume %v for pod %v at %v", b.volName, b.pod.UID, dir)

	// Wrap EmptyDir, let it do the setup.
	wrapped, err := b.plugin.host.NewWrapperMounter(b.volName, wrappedVolumeSpec(), &b.pod, *b.opts)
	if err != nil {
		return err
	}

	optional := b.source.Optional != nil && *b.source.Optional
	secret, err := b.getSecret(b.pod.Namespace, b.source.SecretName)
	if err != nil {
		if !(errors.IsNotFound(err) && optional) {
			klog.Errorf("Couldn't get secret %v/%v: %v", b.pod.Namespace, b.source.SecretName, err)
			return err
		}
		secret = &v1.Secret{
			ObjectMeta: metav1.ObjectMeta{
				Namespace: b.pod.Namespace,
				Name:      b.source.SecretName,
			},
		}
	}

	totalBytes := totalSecretBytes(secret)
	klog.V(3).Infof("Received secret %v/%v containing (%v) pieces of data, %v total bytes",
		b.pod.Namespace,
		b.source.SecretName,
		len(secret.Data),
		totalBytes)

	payload, err := MakePayload(b.source.Items, secret, b.source.DefaultMode, optional)
	if err != nil {
		return err
	}

	setupSuccess := false
	if err := wrapped.SetUpAt(dir, mounterArgs); err != nil {
		return err
	}
	if err := volumeutil.MakeNestedMountpoints(b.volName, dir, b.pod); err != nil {
		return err
	}

	defer func() {
		// Clean up directories if setup fails
		if !setupSuccess {
			unmounter, unmountCreateErr := b.plugin.NewUnmounter(b.volName, b.podUID)
			if unmountCreateErr != nil {
				klog.Errorf("error cleaning up mount %s after failure. Create unmounter failed with %v", b.volName, unmountCreateErr)
				return
			}
			tearDownErr := unmounter.TearDown()
			if tearDownErr != nil {
				klog.Errorf("error tearing down volume %s with : %v", b.volName, tearDownErr)
			}
		}
	}()

	writerContext := fmt.Sprintf("pod %v/%v volume %v", b.pod.Namespace, b.pod.Name, b.volName)
	writer, err := volumeutil.NewAtomicWriter(dir, writerContext)
	if err != nil {
		klog.Errorf("Error creating atomic writer: %v", err)
		return err
	}

	setPerms := func(_ string) error {
		// This may be the first time writing and new files get created outside the timestamp subdirectory:
		// change the permissions on the whole volume and not only in the timestamp directory.
		return volume.SetVolumeOwnership(b, dir, mounterArgs.FsGroup, nil /*fsGroupChangePolicy*/, volumeutil.FSGroupCompleteHook(b.plugin, nil))
	}
	err = writer.Write(payload, setPerms)
	if err != nil {
		klog.Errorf("Error writing payload to dir: %v", err)
		return err
	}

	setupSuccess = true
	return nil
}