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: preparelayer.go
    path of file: ./repos/kubernetes/vendor/github.com/Microsoft/hcsshim/internal/wclayer
    
    the code of the file until where you have to start completion: package wclayer

import (
	"context"
	"strings"
	"sync"

	"github.com/Microsoft/hcsshim/internal/hcserror"
	"github.com/Microsoft/hcsshim/internal/oc"
	"go.opencensus.io/trace"
)

var prepareLayerLock sync.Mutex

// PrepareLayer finds a mounted read-write layer matching path and enables the
// the filesystem filter for use on that layer.  This requires the paths to all
// parent layers, and is necessary in order to view or interact with the layer
// as an actual filesystem (reading and
    
func PrepareLayer(ctx context.Context, path string, parentLayerPaths []string) (err error) {
	title := "hcsshim::PrepareLayer"
	ctx, span := trace.StartSpan(ctx, title)
	defer span.End()
	defer func() { oc.SetSpanStatus(span, err) }()
	span.AddAttributes(
		trace.StringAttribute("path", path),
		trace.StringAttribute("parentLayerPaths", strings.Join(parentLayerPaths, ", ")))

	// Generate layer descriptors
	layers, err := layerPathsToDescriptors(ctx, parentLayerPaths)
	if err != nil {
		return err
	}

	// This lock is a temporary workaround for a Windows bug. Only allowing one
	// call to prepareLayer at a time vastly reduces the chance of a timeout.
	prepareLayerLock.Lock()
	defer prepareLayerLock.Unlock()
	err = prepareLayer(&stdDriverInfo, path, layers)
	if err != nil {
		return hcserror.New(err, title+" - failed", "")
	}
	return nil
}