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: zfs.go
    path of file: ./repos/moby/daemon/graphdriver/zfs
    
    the code of the file until where you have to start completion: //go:build linux || freebsd

package zfs // import "github.com/docker/docker/daemon/graphdriver/zfs"

import (
	"context"
	"fmt"
	"os"
	"os/exec"
	"path"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/containerd/log"
	"github.com/docker/docker/daemon/graphdriver"
	"github.com/docker/docker/pkg/idtools"
	"github.com/docker/docker/pkg/parsers"
	zfs "github.com/mistifyio/go-zfs/v3"
	"github.com/moby/locker"
	"github.com/moby/sys/mount"
	"github.com/moby/sys/mountinfo"
	"github.com/opencontainers/selinux/go-selinux/label"
	"github.com/pkg/errors"
	"golang.org/x/sys/unix"
)

type zfsOptions struct {
	fsName    string
	mountPath string
}

func in
    
func Init(base string, opt []string, idMap idtools.IdentityMapping) (graphdriver.Driver, error) {
	var err error

	logger := log.G(context.TODO()).WithField("storage-driver", "zfs")

	if _, err := exec.LookPath("zfs"); err != nil {
		logger.Debugf("zfs command is not available: %v", err)
		return nil, graphdriver.ErrPrerequisites
	}

	file, err := os.OpenFile("/dev/zfs", os.O_RDWR, 0o600)
	if err != nil {
		logger.Debugf("cannot open /dev/zfs: %v", err)
		return nil, graphdriver.ErrPrerequisites
	}
	defer file.Close()

	options, err := parseOptions(opt)
	if err != nil {
		return nil, err
	}
	options.mountPath = base

	rootdir := path.Dir(base)

	if options.fsName == "" {
		err = checkRootdirFs(rootdir)
		if err != nil {
			return nil, err
		}
	}

	if options.fsName == "" {
		options.fsName, err = lookupZfsDataset(rootdir)
		if err != nil {
			return nil, err
		}
	}

	zfs.SetLogger(new(Logger))

	filesystems, err := zfs.Filesystems(options.fsName)
	if err != nil {
		return nil, fmt.Errorf("Cannot find root filesystem %s: %v", options.fsName, err)
	}

	filesystemsCache := make(map[string]bool, len(filesystems))
	var rootDataset *zfs.Dataset
	for _, fs := range filesystems {
		if fs.Name == options.fsName {
			rootDataset = fs
		}
		filesystemsCache[fs.Name] = true
	}

	if rootDataset == nil {
		return nil, fmt.Errorf("BUG: zfs get all -t filesystem -rHp '%s' should contain '%s'", options.fsName, options.fsName)
	}

	dirID := idtools.Identity{
		UID: idtools.CurrentIdentity().UID,
		GID: idMap.RootPair().GID,
	}
	if err := idtools.MkdirAllAndChown(base, 0o710, dirID); err != nil {
		return nil, fmt.Errorf("Failed to create '%s': %v", base, err)
	}

	d := &Driver{
		dataset:          rootDataset,
		options:          options,
		filesystemsCache: filesystemsCache,
		idMap:            idMap,
		ctr:              graphdriver.NewRefCounter(graphdriver.NewDefaultChecker()),
		locker:           locker.New(),
	}
	return graphdriver.NewNaiveDiffDriver(d, idMap), nil
}