HDFS-16351. add path exception information in FSNamesystem

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -8610,7 +8610,7 @@ void checkAccess(String src, FsAction mode) throws IOException {
         src = iip.getPath();
         INode inode = iip.getLastINode();
         if (inode == null) {
-          throw new FileNotFoundException("Path not found");
+          throw new FileNotFoundException("Path not found: " + src);
         }
         if (isPermissionEnabled) {
           dir.checkPathAccess(pc, iip, mode);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSPermission.java

@@ -30,6 +30,7 @@
 import java.util.Map;
 import java.util.Random;
 
+import org.apache.hadoop.test.GenericTestUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.apache.hadoop.conf.Configuration;
@@ -260,6 +261,33 @@ private void createAndCheckPermission(OpType op, Path name, short umask,
     checkPermission(name, expectedPermission, delete);
   }
 
+  @Test
+  public void testFSNamesystemCheckAccess() throws Exception {
+    Path testValidDir = new Path("/test1");
+    Path testValidFile = new Path("/test1/file1");
+    Path testInvalidPath = new Path("/test2");
+    fs = FileSystem.get(conf);
+
+    fs.mkdirs(testValidDir);
+    fs.create(testValidFile);
+
+    fs.access(testValidDir, FsAction.READ);
+    fs.access(testValidFile, FsAction.READ);
+
+    assertTrue(fs.exists(testValidDir));
+    assertTrue(fs.exists(testValidFile));
+
+    try {
+      fs.access(testInvalidPath, FsAction.READ);
+      fail("Failed to get expected FileNotFoundException");
+    } catch (FileNotFoundException e) {
+      GenericTestUtils.assertExceptionContains(
+              "Path not found: " + testInvalidPath, e);
+    } finally {
+      fs.delete(testValidDir, true);
+    }
+  }
+
   /* Check if the permission of a file/directory is the same as the
    * expected permission; If the delete flag is true, delete the
    * file/directory afterwards.
@@ -289,7 +317,7 @@ public void testImmutableFsPermission() throws IOException {
     fs.setPermission(new Path("/"),
         FsPermission.createImmutable((short)0777));
   }
-  
+
   @Test(timeout=30000)
   public void testTrashPermission() throws Exception {
     //  /BSS                  user1:group2 777

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestFSNamesystem.java

@@ -26,6 +26,7 @@
 import static org.junit.Assert.*;
 
 import java.io.File;
+import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.net.InetAddress;
 import java.net.URI;
@@ -34,6 +35,7 @@
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.FileUtil;
+import org.apache.hadoop.fs.permission.FsAction;
 import org.apache.hadoop.ha.HAServiceProtocol;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.DFSTestUtil;
@@ -46,6 +48,7 @@
 import org.apache.hadoop.hdfs.server.namenode.snapshot.Snapshot;
 import org.apache.hadoop.hdfs.server.namenode.top.TopAuditLogger;
 import org.apache.hadoop.hdfs.server.protocol.NamespaceInfo;
+import org.apache.hadoop.test.GenericTestUtils;
 import org.apache.hadoop.test.Whitebox;
 import org.junit.After;
 import org.junit.Test;
@@ -120,6 +123,23 @@ public void testStartupSafemode() throws IOException {
       + "isInSafeMode still returned false",  fsn.isInSafeMode());
   }
 
+  @Test
+  public void testCheckAccess() throws IOException {
+    Configuration conf = new Configuration();
+    FSImage fsImage = Mockito.mock(FSImage.class);
+    FSEditLog fsEditLog = Mockito.mock(FSEditLog.class);
+    Mockito.when(fsImage.getEditLog()).thenReturn(fsEditLog);
+    String src = "/test1";
+    FSNamesystem fsn = new FSNamesystem(conf, fsImage);
+    try {
+      fsn.checkAccess(src, FsAction.READ);
+      fail("Failed to get expected FileNotFoundException");
+    } catch (FileNotFoundException e) {
+      GenericTestUtils.assertExceptionContains(
+              "Path not found: " + src, e);
+    }
+  }
+
   @Test
   public void testReplQueuesActiveAfterStartupSafemode() throws IOException, InterruptedException{
     Configuration conf = new Configuration();