HDFS-12748. NameNode memory leak when accessing webhdfs GETHOMEDIRECTORY. Contributed by Weiwei Yang.

(cherry picked from commit 6c8cfd135eea15e3dfd76dd33af24a9a8c38fd8d)
(cherry picked from commit 3f112e7347fa7b75eab3a417c9d6520ca8b3053e)

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSUtilClient.java

@@ -682,4 +682,25 @@ public class DFSUtilClient {
     iioe.initCause(e);
     return iioe;
   }
+
+  /**
+   * Returns current user home directory under a home directory prefix.
+   * The home directory prefix can be defined by
+   * {@link HdfsClientConfigKeys#DFS_USER_HOME_DIR_PREFIX_KEY}.
+   * User info is obtained from given {@link UserGroupInformation}.
+   * @param conf configuration
+   * @param ugi {@link UserGroupInformation} of current user.
+   * @return the home directory of current user.
+   */
+  public static Path getHomeDirectory(Configuration conf,
+      UserGroupInformation ugi) {
+    String userHomePrefix = HdfsClientConfigKeys
+        .DFS_USER_HOME_DIR_PREFIX_DEFAULT;
+    if (conf != null) {
+      userHomePrefix = conf.get(
+          HdfsClientConfigKeys.DFS_USER_HOME_DIR_PREFIX_KEY,
+          HdfsClientConfigKeys.DFS_USER_HOME_DIR_PREFIX_DEFAULT);
+    }
+    return new Path(userHomePrefix + "/" + ugi.getShortUserName());
+  }
 }

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java

@@ -119,8 +119,6 @@ public class DistributedFileSystem extends FileSystem
     implements KeyProviderTokenIssuer {
   private Path workingDir;
   private URI uri;
-  private String homeDirPrefix =
-      HdfsClientConfigKeys.DFS_USER_HOME_DIR_PREFIX_DEFAULT;
 
   DFSClient dfs;
   private boolean verifyChecksum = true;
@@ -157,9 +155,6 @@ public class DistributedFileSystem extends FileSystem
     if (host == null) {
       throw new IOException("Incomplete HDFS URI, no host: "+ uri);
     }
-    homeDirPrefix = conf.get(
-        HdfsClientConfigKeys.DFS_USER_HOME_DIR_PREFIX_KEY,
-        HdfsClientConfigKeys.DFS_USER_HOME_DIR_PREFIX_DEFAULT);
 
     this.dfs = new DFSClient(uri, conf, statistics);
     this.uri = URI.create(uri.getScheme()+"://"+uri.getAuthority());
@@ -202,8 +197,7 @@ public class DistributedFileSystem extends FileSystem
 
   @Override
   public Path getHomeDirectory() {
-    return makeQualified(new Path(homeDirPrefix + "/"
-        + dfs.ugi.getShortUserName()));
+    return makeQualified(DFSUtilClient.getHomeDirectory(getConf(), dfs.ugi));
   }
 
   /**

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/web/resources/NamenodeWebHdfsMethods.java

@@ -70,6 +70,7 @@ import org.apache.hadoop.fs.permission.AclStatus;
 import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSUtil;
+import org.apache.hadoop.hdfs.DFSUtilClient;
 import org.apache.hadoop.hdfs.XAttrHelper;
 import org.apache.hadoop.hdfs.protocol.BlockStoragePolicy;
 import org.apache.hadoop.hdfs.protocol.ClientProtocol;
@@ -1093,9 +1094,8 @@ public class NamenodeWebHdfsMethods {
       return Response.ok(js).type(MediaType.APPLICATION_JSON).build();
     }
     case GETHOMEDIRECTORY: {
-      final String js = JsonUtil.toJsonString("Path",
-          FileSystem.get(conf != null ? conf : new Configuration())
-              .getHomeDirectory().toUri().getPath());
+      String userHome = DFSUtilClient.getHomeDirectory(conf, ugi).toString();
+      final String js = JsonUtil.toJsonString("Path", userHome);
       return Response.ok(js).type(MediaType.APPLICATION_JSON).build();
     }
     case GETACLSTATUS: {