const (
	xfs  = "XFS"
	ext4 = "EXT4"
)

// WalkDir will traverse a directory and return all entries found.
// On success a sorted meta cache stream will be returned.
// Metadata has data stripped, if any.
// The function tries to quit as fast as the context is canceled to avoid further drive IO
func (s *xlStorage) WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writer) (err error) {

	if err := d.calcError(); err != nil {
		return err
	}
	return d.disk.DeleteVol(ctx, volume, forceDelete)
}

func (d *naughtyDisk) WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writer) error {
	if err := d.calcError(); err != nil {
		return err
	}
	return d.disk.WalkDir(ctx, opts, wr)
}

func (d *naughtyDisk) ListDir(ctx context.Context, origvolume, volume, dirPath string, count int) (entries []string, err error) {

	StatVol(ctx context.Context, volume string) (vol VolInfo, err error)
	DeleteVol(ctx context.Context, volume string, forceDelete bool) (err error)

	// WalkDir will walk a directory on disk and return a metacache stream on wr.
	WalkDir(ctx context.Context, opts WalkDirOptions, wr io.Writer) error

	// Metadata operations

		readers[i] = newMetacacheReader(r)
		d := disks[i]

		// Send request to each disk.
		go func() {
			var werr error
			if d == nil {
				werr = errDiskNotFound
			} else {
				werr = d.WalkDir(ctx, WalkDirOptions{
					Limit:          opts.perDiskLimit,
					Bucket:         opts.bucket,
					BaseDir:        opts.path,
					Recursive:      opts.recursive,
					ReportNotFound: opts.reportNotFound,