HDFS-16351. Add path exception information in FSNamesystem (#3713). Contributed by guophilipse.

Reviewed-by: Viraj Jasani <vjasani@apache.org>
Signed-off-by: Ayush Saxena <ayushsaxena@apache.org>

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

@@ -8612,7 +8612,7 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
         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

@@ -44,6 +44,7 @@ import org.apache.hadoop.fs.permission.FsPermission;
 import org.apache.hadoop.fs.permission.FsAction;
 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;
 import org.junit.Before;
@@ -260,6 +261,17 @@ public class TestDFSPermission {
     checkPermission(name, expectedPermission, delete);
   }
 
+  @Test
+  public void testFSNamesystemCheckAccess() throws Exception{
+    Path testInvalidPath = new Path("/test2");
+    fs = FileSystem.get(conf);
+
+    LambdaTestUtils.intercept(
+        FileNotFoundException.class,
+        "Path not found: " + testInvalidPath,
+        () -> fs.access(testInvalidPath, FsAction.READ));
+  }
+
   /* 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.