HDFS-14722. RBF: GetMountPointStatus should return mountTable information when getFileInfoAll throw IOException. Contributed by xuzq.

Author: ayushtkn

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterClientProtocol.java

@@ -1913,6 +1913,10 @@ private HdfsFileStatus getMountPointStatus(
         MountTableResolver mountTable = (MountTableResolver) subclusterResolver;
         MountTable entry = mountTable.getMountPoint(mName);
         if (entry != null) {
+          permission = entry.getMode();
+          owner = entry.getOwnerName();
+          group = entry.getGroupName();
+
           RemoteMethod method = new RemoteMethod("getFileInfo",
               new Class<?>[] {String.class}, new RemoteParam());
           HdfsFileStatus fInfo = getFileInfoAll(
@@ -1922,10 +1926,6 @@ private HdfsFileStatus getMountPointStatus(
             owner = fInfo.getOwner();
             group = fInfo.getGroup();
             childrenNum = fInfo.getChildrenNum();
-          } else {
-            permission = entry.getMode();
-            owner = entry.getOwnerName();
-            group = entry.getGroupName();
           }
         }
       } catch (IOException e) {

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterMountTable.java

@@ -24,6 +24,7 @@
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.net.URISyntaxException;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -53,6 +54,7 @@
 import org.apache.hadoop.hdfs.server.federation.store.protocol.RemoveMountTableEntryRequest;
 import org.apache.hadoop.hdfs.server.federation.store.records.MountTable;
 import org.apache.hadoop.security.AccessControlException;
+import org.apache.hadoop.security.UserGroupInformation;
 import org.apache.hadoop.test.LambdaTestUtils;
 import org.apache.hadoop.util.Time;
 import org.junit.After;
@@ -254,6 +256,61 @@ public void testListFilesTime() throws Exception {
     }
   }
 
+  /**
+   * Verify that the file/dir status with IOException in getMountPointStatus.
+   */
+  @Test
+  public void testGetMountPointStatusWithIOException()
+      throws IOException, InterruptedException {
+    try {
+      // Add mount table entry.
+      MountTable addEntry = MountTable.newInstance("/testA",
+          Collections.singletonMap("ns0", "/testA"));
+      assertTrue(addMountTable(addEntry));
+      addEntry = MountTable.newInstance("/testA/testB",
+          Collections.singletonMap("ns0", "/testA/testB"));
+      assertTrue(addMountTable(addEntry));
+      addEntry = MountTable.newInstance("/testB",
+          Collections.singletonMap("ns0", "/test1/testB"));
+      addEntry.setOwnerName("userB");
+      addEntry.setGroupName("groupB");
+      assertTrue(addMountTable(addEntry));
+
+      assertTrue(nnFs0.mkdirs(new Path("/test1")));
+      nnFs0.setPermission(new Path("/test1"),
+          FsPermission.createImmutable((short) 0700));
+
+      // Use mock user to getListing through router.
+      UserGroupInformation user = UserGroupInformation.createUserForTesting(
+          "mock_user", new String[] {"mock_group"});
+      LambdaTestUtils.doAs(user, () -> getListing("/testA"));
+    } finally {
+      nnFs0.delete(new Path("/test1"), true);
+    }
+  }
+
+  /**
+   * GetListing of testPath through router.
+   */
+  private void getListing(String testPath)
+      throws IOException, URISyntaxException {
+    ClientProtocol clientProtocol1 =
+        routerContext.getClient().getNamenode();
+    DirectoryListing listing = clientProtocol1.getListing(testPath,
+        HdfsFileStatus.EMPTY_NAME, false);
+
+    assertEquals(1, listing.getPartialListing().length);
+    HdfsFileStatus fileStatus = listing.getPartialListing()[0];
+    String currentOwner = fileStatus.getOwner();
+    String currentGroup = fileStatus.getGroup();
+    String currentFileName =
+        fileStatus.getFullPath(new Path("/")).getName();
+
+    assertEquals("testB", currentFileName);
+    assertEquals("userB", currentOwner);
+    assertEquals("groupB", currentGroup);
+  }
+
   /**
    * Verify permission for a mount point when the actual destination is not
    * present. It returns the permissions of the mount point.