HADOOP-12077. Provide a multi-URI replication Inode for ViewFs. Contributed by Gera Shegalov

(cherry picked from commit 6d3d01d7ad)

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/viewfs/ConfigUtil.java

@@ -68,6 +68,32 @@ public class ConfigUtil {
         src, target);   
   }
   
+  /**
+   *
+   * @param conf
+   * @param mountTableName
+   * @param src
+   * @param settings
+   * @param targets
+   */
+  public static void addLinkNfly(Configuration conf, String mountTableName,
+      String src, String settings, final URI ... targets) {
+
+    settings = settings == null
+        ? "minReplication=2,repairOnRead=true"
+        : settings;
+
+    conf.set(getConfigViewFsPrefix(mountTableName) + "." +
+            Constants.CONFIG_VIEWFS_LINK_NFLY + "." + settings + "." + src,
+        StringUtils.uriToString(targets));
+  }
+
+  public static void addLinkNfly(final Configuration conf, final String src,
+      final URI ... targets) {
+    addLinkNfly(conf, Constants.CONFIG_VIEWFS_DEFAULT_MOUNT_TABLE, src, null,
+        targets);
+  }
+
   /**
    * Add config variable for homedir for default mount table
    * @param conf - add to this conf