HDFS-7552. Change FsVolumeList toString() to fix TestDataNodeVolumeFailureToleration (Liang Xie via Colin P. McCabe)

(cherry picked from commit a4876c130f1627e59ef055e586640d1933fc49af)

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -364,6 +364,9 @@ Release 2.7.0 - UNRELEASED
     HDFS-7431. log message for InvalidMagicNumberException may be incorrect.
     (Yi Liu via cnauroth)
 
+    HDFS-7552. Change FsVolumeList toString() to fix
+    TestDataNodeVolumeFailureToleration (Liang Xie via Colin P. McCabe)
+
 Release 2.6.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsVolumeList.java

@@ -213,7 +213,7 @@ class FsVolumeList {
 
   @Override
   public String toString() {
-    return volumes.toString();
+    return Arrays.toString(volumes.get());
   }
 
   /**