diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 50192ae63b9..2cf9509791f 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -899,6 +899,9 @@ Release 2.8.0 - UNRELEASED
     HADOOP-12089. StorageException complaining " no lease ID" when updating
     FolderLastModifiedTime in WASB. (Duo Xu via cnauroth)
 
+    HADOOP-12154. FileSystem#getUsed() returns the file length only from root '/'
+    (J.Andreina via vinayakumarb)
+
 Release 2.7.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java
index 1d7bc875cc3..c98074ae6d0 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystem.java
@@ -2085,9 +2085,9 @@ public abstract class FileSystem extends Configured implements Closeable {
   /** Return the total size of all files in the filesystem.*/
   public long getUsed() throws IOException{
     long used = 0;
-    FileStatus[] files = listStatus(new Path("/"));
-    for(FileStatus file:files){
-      used += file.getLen();
+    RemoteIterator<LocatedFileStatus> files = listFiles(new Path("/"), true);
+    while (files.hasNext()) {
+      used += files.next().getLen();
     }
     return used;
   }
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSShell.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSShell.java
index 2df31c42e29..13861241a61 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSShell.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSShell.java
@@ -913,6 +913,32 @@ public class TestDFSShell {
       cluster.shutdown();
     }
   }
+
+  @Test(timeout = 30000)
+  public void testTotalSizeOfAllFiles() throws Exception {
+    Configuration conf = new HdfsConfiguration();
+    MiniDFSCluster cluster = null;
+    try {
+      cluster = new MiniDFSCluster.Builder(conf).numDataNodes(1).build();
+      FileSystem fs = cluster.getFileSystem();
+      // create file under root
+      FSDataOutputStream File1 = fs.create(new Path("/File1"));
+      File1.write("hi".getBytes());
+      File1.close();
+      // create file under sub-folder
+      FSDataOutputStream File2 = fs.create(new Path("/Folder1/File2"));
+      File2.write("hi".getBytes());
+      File2.close();
+      // getUsed() should return total length of all the files in Filesystem
+      assertEquals(4, fs.getUsed());
+    } finally {
+      if (cluster != null) {
+        cluster.shutdown();
+        cluster = null;
+      }
+    }
+  }
+
   private static void runCount(String path, long dirs, long files, FsShell shell
     ) throws IOException {
     ByteArrayOutputStream bytes = new ByteArrayOutputStream();