// and check if that disk
					// appears in outDatedDisks.
					tamperedIndex = index
					filePath := pathJoin(erasureDisks[index].String(), bucket, object, fi.DataDir, "part.1")
					f, err := os.OpenFile(filePath, os.O_WRONLY|os.O_SYNC, 0)
					if err != nil {
						t.Fatalf("Failed to open %s: %s\n", filePath, err)
					}
					f.WriteString("oops") // Will cause bitrot error
					f.Close()
					break
				}