return l.do(f)
	}
	return nil
}

func (l *Init) do(f func() error) error {
	l.m.Lock()
	defer l.m.Unlock()
	if atomic.LoadUint32(&l.done) == 0 {
		if err := f(); err != nil {
			return err
		}
		// Mark as done only when f() is successful
		atomic.StoreUint32(&l.done, 1)
	}
	return nil
}

// DoWithContext is similar to Do except that it accepts a context as an argument to be passed.

	r := z.rebalMeta
	poolStats := r.PoolStats[poolIdx]
	if poolStats.Info.Status == rebalCompleted {
		return true
	}

	pfi := float64(poolStats.InitFreeSpace+poolStats.Bytes) / float64(poolStats.InitCapacity)
	// Mark pool rebalance as done if within 5% from PercentFreeGoal.
	if diff := math.Abs(pfi - r.PercentFreeGoal); diff <= 0.05 {
		r.PoolStats[poolIdx].Info.Status = rebalCompleted
		r.PoolStats[poolIdx].Info.EndTime = time.Now()

// errFileNotFound - cannot find requested file version.
var errFileVersionNotFound = StorageErr("file version not found")

// errTooManyOpenFiles - too many open files.
var errTooManyOpenFiles = StorageErr("too many open files, please increase 'ulimit -n'")

// errFileNameTooLong - given file name is too long than supported length.
var errFileNameTooLong = StorageErr("file name too long")

		},
	}
	createUsageTestFiles(t, base, bucket, files)
	err = os.RemoveAll(filepath.Join(base, bucket, "dir1/dira/dirasub/dcfile"))
	if err != nil {
		t.Fatal(err)
	}
	// Changed dir must be picked up in this many cycles.
	for i := 0; i < dataUsageUpdateDirCycles; i++ {
		got, err = scanDataFolder(context.Background(), nil, base, got, getSize, 0, weSleep)
		got.Info.NextCycle++
		if err != nil {
			t.Fatal(err)
		}
	}

	serverPools.FilterMaxUsed(100 - (100 * diskReserveFraction))
	total := serverPools.TotalAvailable()
	if total == 0 {
		return -1
	}
	// choose when we reach this many
	choose := rand.Uint64() % total
	atTotal := uint64(0)
	for _, pool := range serverPools {
		atTotal += pool.Available
		if atTotal > choose && pool.Available > 0 {
			return pool.Index
		}
	}

}

// StorageFull storage ran out of space.
type StorageFull struct{}

func (e StorageFull) Error() string {
	return "Storage reached its minimum free drive threshold."
}

// SlowDown  too many file descriptors open or backend busy .
type SlowDown struct{}

func (e SlowDown) Error() string {
	return "Please reduce your request rate"
}

// RQErrType reason for read quorum error.
type RQErrType int

}

// Tests validate the order of result of ListBuckets.
func testListBucketsOrder(obj ObjectLayer, instanceType string, t TestErrHandler) {
	// if implementation contains a map, order of map keys will vary.
	// this ensures they return in the same order each time.
	// add one and test exists.
	err := obj.MakeBucket(context.Background(), "bucket1", MakeBucketOptions{})
	if err != nil {

						VersionID: goi.VersionID,
					}
				}
				return goi, ObjectNotFound{
					Bucket: bucket,
					Object: object,
				}
			}
		}
	}

	//  Determine whether to mark object deleted for replication
	markDelete := goi.VersionID != ""

	// Default deleteMarker to true if object is under versioning
	deleteMarker := opts.Versioned

	if opts.VersionID != "" {

		"Content-Disposition",
		"Last-Modified",
		"Content-Language",
		"Cache-Control",
		"Retry-After",
		"X-Amz-Bucket-Region",
		"Expires",
		"X-Amz*",
		"X-Amz*",
		"*",
	}
	expectedMap.Set("Vary", "Origin")

	req, _ := http.NewRequest(http.MethodOptions, s.endPoint, nil)
	req.Header.Set("Origin", "http://foobar.com")
	res, err := s.client.Do(req)
	if err != nil {
		c.Fatal(err)
	}

	OptimizeEnv = "MINIO_STORAGE_CLASS_OPTIMIZE"
	// Inline block indicates the size of the shard
	// that is considered for inlining, remember this
	// shard value is the value per drive shard it
	// will vary based on the parity that is configured
	// for the STANDARD storage_class.
	// inlining means data and metadata are written
	// together in a single file i.e xl.meta
	InlineBlockEnv = "MINIO_STORAGE_CLASS_INLINE_BLOCK"