fix: improper ticker usage in goroutines (#11468)

- lock maintenance loop was incorrectly sleeping
  as well as using ticker badly, leading to
  extra expiration routines getting triggered
  that could flood the network.

- multipart upload cleanup should be based on
  timer instead of ticker, to ensure that long
  running jobs don't get triggered twice.

- make sure to get right lockers for object name

cmd/fs-v1-multipart.go

@@ -849,14 +849,17 @@ func (fs *FSObjects) AbortMultipartUpload(ctx context.Context, bucket, object, u
 // on all buckets for every `cleanupInterval`, this function is
 // blocking and should be run in a go-routine.
 func (fs *FSObjects) cleanupStaleUploads(ctx context.Context, cleanupInterval, expiry time.Duration) {
-	ticker := time.NewTicker(cleanupInterval)
-	defer ticker.Stop()
+	timer := time.NewTimer(cleanupInterval)
+	defer timer.Stop()
 
 	for {
 		select {
 		case <-ctx.Done():
 			return
-		case <-ticker.C:
+		case <-timer.C:
+			// Reset for the next interval
+			timer.Reset(cleanupInterval)
+
 			now := time.Now()
 			entries, err := readDir(pathJoin(fs.fsPath, minioMetaMultipartBucket))
 			if err != nil {