Fix missing GetObjectNInfo Closure (#11243)

Review for missing Close of returned value from `GetObjectNInfo`.

This was often obscured by the stuff that auto-unlocks when reaching EOF.

cmd/bucket-lifecycle.go

@@ -341,13 +341,13 @@ func transitionObject(ctx context.Context, objectAPI ObjectLayer, objInfo Object
 	}
 	oi := gr.ObjInfo
 	if oi.TransitionStatus == lifecycle.TransitionComplete {
-		gr.Close() // make sure to avoid leaks.
+		gr.Close()
 		return nil
 	}
 
 	putOpts := putTransitionOpts(oi)
 	if _, err = tgt.PutObject(ctx, arn.Bucket, oi.Name, gr, oi.Size, "", "", putOpts); err != nil {
-		gr.Close() // make sure to avoid leaks.
+		gr.Close()
 		return err
 	}
 	gr.Close()

cmd/bucket-replication.go

@@ -471,6 +471,8 @@ func replicateObject(ctx context.Context, objInfo ObjectInfo, objectAPI ObjectLa
 		for k, v := range putOpts.Header() {
 			headerSize += len(k) + len(v)
 		}
+
+		// r takes over closing gr.
 		r := bandwidth.NewMonitoredReader(ctx, globalBucketMonitor, objInfo.Bucket, objInfo.Name, gr, headerSize, b, target.BandwidthLimit)
 		_, err = tgt.PutObject(ctx, dest.Bucket, object, r, size, "", "", putOpts)
 		if err != nil {

cmd/data-usage-cache.go

@@ -478,6 +478,7 @@ func (d *dataUsageCache) load(ctx context.Context, store objectIO, name string)
 		*d = dataUsageCache{}
 		return nil
 	}
+	defer r.Close()
 	if err := d.deserialize(r); err != nil {
 		*d = dataUsageCache{}
 		logger.LogOnceIf(ctx, err, err.Error())

pkg/bucket/bandwidth/reader.go

@@ -28,7 +28,7 @@ type MonitoredReader struct {
 	bucket            string             // Token to track bucket
 	bucketMeasurement *bucketMeasurement // bucket measurement object
 	object            string             // Token to track object
-	reader            io.Reader          // Reader to wrap
+	reader            io.ReadCloser      // Reader to wrap
 	lastStop          time.Time          // Last timestamp for a measurement
 	headerSize        int                // Size of the header not captured by reader
 	throttle          *throttle          // throttle the rate at which replication occur
@@ -36,8 +36,9 @@ type MonitoredReader struct {
 	closed            bool               // Reader is closed
 }
 
-// NewMonitoredReader returns a io.ReadCloser that reports bandwidth details
+// NewMonitoredReader returns a io.ReadCloser that reports bandwidth details.
-func NewMonitoredReader(ctx context.Context, monitor *Monitor, bucket string, object string, reader io.Reader, headerSize int, bandwidthBytesPerSecond int64, clusterBandwidth int64) *MonitoredReader {
+// The supplied reader will be closed.
+func NewMonitoredReader(ctx context.Context, monitor *Monitor, bucket string, object string, reader io.ReadCloser, headerSize int, bandwidthBytesPerSecond int64, clusterBandwidth int64) *MonitoredReader {
 	timeNow := time.Now()
 	b := monitor.track(bucket, object, timeNow)
 	return &MonitoredReader{
@@ -77,10 +78,9 @@ func (m *MonitoredReader) Read(p []byte) (n int, err error) {
 
 // Close stops tracking the io
 func (m *MonitoredReader) Close() error {
-	rc, ok := m.reader.(io.ReadCloser)
+	if m.closed {
-	m.closed = true
-	if ok {
-		return rc.Close()
-	}
 		return nil
 	}
+	m.closed = true
+	return m.reader.Close()
+}