Fixed the race condition in testViewFsMultipleExportPoint

Author: yakunw2

hadoop-hdfs-project/hadoop-hdfs-nfs/src/main/java/org/apache/hadoop/hdfs/nfs/nfs3/DFSClientCache.java

@@ -170,15 +170,19 @@ private void prepareAddressMap() throws IOException {
       // if a unique nnid, add it to the map
       if (value == null) {
         LOG.info("Added export: {} FileSystem URI: {} with namenodeId: {}",
-            exportPath, exportPath, namenodeId);
+            exportPath, exportURI, namenodeId);
         namenodeUriMap.put(namenodeId, exportURI);
-      } else {
-        // if the nnid already exists, it better be the for the same namenode
+      } else if (!value.equals(exportURI)) {
+        // Only throw exception if different URIs have the same namenode ID
         String msg = String.format("FS:%s, Namenode ID collision for path:%s "
                 + "nnid:%s uri being added:%s existing uri:%s", fs.getScheme(),
             exportPath, namenodeId, exportURI, value);
         LOG.error(msg);
         throw new FileSystemException(msg);
+      } else {
+        // Same URI with same namenode ID - this is expected and safe to ignore
+        LOG.debug("Export path {} resolves to same URI {} as existing entry, skipping",
+            exportPath, exportURI);
       }
     }
   }

hadoop-hdfs-project/hadoop-hdfs-nfs/src/main/java/org/apache/hadoop/hdfs/nfs/nfs3/Nfs3Utils.java

@@ -21,6 +21,7 @@
 import java.net.InetSocketAddress;
 import java.net.URI;
 import java.nio.file.FileSystemException;
+import java.util.Objects;
 
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.Channel;
@@ -242,7 +243,7 @@ public static int getNamenodeId(Configuration conf) {
   public static int getNamenodeId(Configuration conf, URI namenodeURI) {
     InetSocketAddress address =
         DFSUtilClient.getNNAddressCheckLogical(conf, namenodeURI);
-    return address.hashCode();
+    return Objects.hash(namenodeURI.toString(), address.toString());
   }
 
   public static URI getResolvedURI(FileSystem fs, String exportPath)