// from older format, for older format we will rewrite them as
		// newer using PutObject() - this is an optimization to save space
		if dstOpts.Versioned && srcOpts.VersionID != dstOpts.VersionID && !srcInfo.Legacy {
			// CopyObject optimization where we don't create an entire copy
			// of the content, instead we add a reference.
			srcInfo.versionOnly = true

					encodeDirObject(entry.name),
					ObjectOptions{
						DeletePrefix:       true, // use prefix delete to delete all versions at once.
						DeletePrefixObject: true, // use prefix delete on exact object (this is an optimization to avoid fan-out calls)
						NoAuditLog:         true,
					},
				)
				stopFn(err)
				auditLogRebalance(ctx, "Rebalance:DeleteObject", bucket, entry.name, "", err)
				if err != nil {

		reader = etag.Wrap(s2c, actualReader)
		size = -1   // Since compressed size is un-predictable.
		md5hex = "" // Do not try to verify the content.
		sha256hex = ""
	}

	var forceMD5 []byte
	// Optimization: If SSE-KMS and SSE-C did not request Content-Md5. Use uuid as etag. Optionally enable this also
	// for server that is started with `--no-compat`.

		reader = etag.Wrap(s2c, actualReader)
		size = -1   // Since compressed size is un-predictable.
		md5hex = "" // Do not try to verify the content.
		sha256hex = ""
	}

	var forceMD5 []byte
	// Optimization: If SSE-KMS and SSE-C did not request Content-Md5. Use uuid as etag. Optionally enable this also
	// for server that is started with `--no-compat`.

	_, err := objAPI.DeleteObject(ctx, minioMetaBucket, configFile, ObjectOptions{
		DeletePrefix:       true,
		DeletePrefixObject: true, // use prefix delete on exact object (this is an optimization to avoid fan-out calls)
	})
	if err != nil && isErrObjectNotFound(err) {
		return errConfigNotFound
	}
	return err
}

	// Limit the number of returned objects if > 0.
	Limit int

	// DiskID contains the disk ID of the disk.
	// Leave empty to not check disk ID.
	DiskID string
}

// supported FS for Nlink optimization in readdir.
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.

	// Distributed lock owner (constant per running instance).
	erasureLockOwner string

	// List of endpoints provided on the command line.
	endpoints PoolEndpoints

	// String version of all the endpoints, an optimization
	// to avoid url.String() conversion taking CPU on
	// large disk setups.
	endpointStrings []string

	// Total number of sets and the number of disks per set.
	setCount, setDriveCount int

	// The following code is basically called in for.
	// In order to avoid the performance problems caused by repeated compilation of regular expressions,
	// it only needs to be done once outside, so optimization is done here.
	if idx != -1 && regEnLetterAndMidline.MatchString(str[0:idx]) {
		name = str[0:idx]
	} else {
		name = rel.Schema.namer.RelationshipFKName(*rel)
	}

	constraint := Constraint{

	opts.VersionSuspended = globalBucketVersioningSys.PrefixSuspended(obj.Bucket, obj.Name)

	if lcEvent.Action.DeleteAll() {
		opts.DeletePrefix = true
		// use prefix delete on exact object (this is an optimization to avoid fan-out calls)
		opts.DeletePrefixObject = true
	}
	var (
		dobj ObjectInfo
		err  error
	)
	defer func() {
		if err != nil {
			return
		}

	// TODO(rsc): require failure
	args := p.gccCmd()

	// Optimization options can confuse the error messages; remove them.
	nargs := make([]string, 0, len(args)+len(extraArgs))
	for _, arg := range args {
		if !strings.HasPrefix(arg, "-O") {
			nargs = append(nargs, arg)
		}
	}

	// Force -O0 optimization and append extra arguments, but keep the
	// trailing "-" at the end.