return nil
		}
		return err
	}
	if len(data) == 0 {
		// Seems to be empty create a new poolMeta object.
		return nil
	}
	if len(data) <= 4 {
		return fmt.Errorf("poolMeta: no data")
	}
	// Read header
	switch binary.LittleEndian.Uint16(data[0:2]) {
	case poolMetaFormat:
	default:
		return fmt.Errorf("poolMeta: unknown format: %d", binary.LittleEndian.Uint16(data[0:2]))
	}

	} else {
		c.iamUsersMap[key] = u
	}
	c.updatedAt = time.Now()
	return nil
}

// IAMStorageAPI defines an interface for the IAM persistence layer
type IAMStorageAPI interface {
	// The role of the read-write lock is to prevent go routines from
	// concurrently reading and writing the IAM storage. The (r)lock()
	// functions return the iamCache. The cache can be safely written to
	// only when returned by `lock()`.

}

type latencyStat struct {
	lastmin lastMinuteLatency
	curr    time.Duration
	avg     time.Duration
	peak    time.Duration
	N       int64
}

func (l *latencyStat) update(d time.Duration) {
	l.lastmin.add(d)
	l.N++
	if d > l.peak {
		l.peak = d
	}
	l.curr = l.lastmin.getTotal().avg()
	l.avg = time.Duration((int64(l.avg)*(l.N-1) + int64(l.curr)) / l.N)
}

	case ObjectAccessedGetRetention:
		return "s3:ObjectAccessed:GetRetention"
	case ObjectAccessedGetLegalHold:
		return "s3:ObjectAccessed:GetLegalHold"
	case ObjectAccessedHead:
		return "s3:ObjectAccessed:Head"
	case ObjectAccessedAttributes:
		return "s3:ObjectAccessed:Attributes"
	case ObjectCreatedAll:
		return "s3:ObjectCreated:*"
	case ObjectCreatedCompleteMultipartUpload:

	c.Assert(response.StatusCode, http.StatusNoContent)
}

// TestNonExistentBucket - Asserts response for HEAD on non-existent bucket.
func (s *TestSuiteCommon) TestNonExistentBucket(c *check) {
	// generate a random bucket name.
	bucketName := getRandomBucketName()
	// create request to HEAD on the bucket.
	// HEAD on an bucket helps validate the existence of the bucket.

	return MetricDescription{
		Namespace: nodeMetricNamespace,
		Subsystem: ioSubsystem,
		Name:      readBytes,
		Help:      "Total bytes read by the process from the underlying storage system, /proc/[pid]/io read_bytes",
		Type:      counterMetric,
	}
}

func getMinioProcessIOWriteCachedBytesMD() MetricDescription {
	return MetricDescription{
		Namespace: nodeMetricNamespace,

		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}

	api.getObjectAttributesHandler(ctx, objectAPI, bucket, object, w, r)
}

// HeadObjectHandler - HEAD Object
// -----------
// The HEAD operation retrieves metadata from an object without returning the object itself.
func (api objectAPIHandlers) HeadObjectHandler(w http.ResponseWriter, r *http.Request) {
	ctx := newContext(r, w, "HeadObject")

		DefaultKeyID: stat.DefaultKey,
		Endpoints:    make(map[string]madmin.ItemState, len(stat.Endpoints)),
	}
	for _, endpoint := range stat.Endpoints {
		status.Endpoints[endpoint] = madmin.ItemOnline // TODO(aead): Implement an online check for mTLS
	}

	resp, err := json.Marshal(status)
	if err != nil {
		writeCustomErrorResponseJSON(ctx, w, errorCodes.ToAPIErr(ErrInternalError), err.Error(), r.URL)
		return
	}

		panic(fmt.Errorf(format, args...))
	}
	if p.lineNum == p.errorLine {
		// Only one error per line.
		return
	}
	p.errorLine = p.lineNum
	if p.lex != nil {
		// Put file and line information on head of message.
		format = "%s:%d: " + format + "\n"
		args = append([]interface{}{p.lex.File(), p.lineNum}, args...)
	}
	fmt.Fprintf(p.errorWriter, format, args...)
	p.errorCount++
	if p.errorCount > 10 && !*flags.AllErrors {

	derrs := make([]error, len(poolIndices))
	dobjects := make([]ObjectInfo, len(poolIndices))

	// Delete concurrently in all server pools that reported no error or read quorum error
	// where the read quorum issue is from metadata inconsistency.
	var wg sync.WaitGroup
	for idx, pe := range poolIndices {
		if v, ok := pe.Err.(InsufficientReadQuorum); ok && v.Type != RQInconsistentMeta {