HADOOP-12056. Use DirectoryStream in DiskChecker#checkDirs to detect errors when listing a directory. Contributed by Zhihai Xu.

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -637,6 +637,9 @@ Release 2.8.0 - UNRELEASED
     HADOOP-12059. S3Credentials should support use of CredentialProvider.
     (Sean Busbey via wang)
 
+    HADOOP-12056. Use DirectoryStream in DiskChecker#checkDirs to detect
+    errors when listing a directory. (Zhihai Xu via wang)
+
   OPTIMIZATIONS
 
     HADOOP-11785. Reduce the number of listStatus operation in distcp

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/DiskChecker.java

@@ -20,6 +20,9 @@ package org.apache.hadoop.util;
 
 import java.io.File;
 import java.io.IOException;
+import java.nio.file.DirectoryStream;
+import java.nio.file.DirectoryIteratorException;
+import java.nio.file.Files;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
@@ -86,11 +89,24 @@ public class DiskChecker {
    */
   public static void checkDirs(File dir) throws DiskErrorException {
     checkDir(dir);
-    for (File child : dir.listFiles()) {
+    IOException ex = null;
+    try (DirectoryStream<java.nio.file.Path> stream =
+        Files.newDirectoryStream(dir.toPath())) {
+      for (java.nio.file.Path entry: stream) {
+        File child = entry.toFile();
         if (child.isDirectory()) {
           checkDirs(child);
         }
       }
+    } catch (DirectoryIteratorException de) {
+      ex = de.getCause();
+    } catch (IOException ie) {
+      ex = ie;
+    }
+    if (ex != null) {
+      throw new DiskErrorException("I/O error when open a directory: "
+          + dir.toString(), ex);
+    }
   }
 
   /**

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/util/TestDiskChecker.java

@@ -32,6 +32,7 @@ import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.LocalFileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.test.GenericTestUtils;
 import org.apache.hadoop.util.DiskChecker.DiskErrorException;
 import org.apache.hadoop.util.Shell;
 
@@ -180,4 +181,25 @@ public class TestDiskChecker {
     System.out.println("checkDir success: " + success);
 
   }
+
+  @Test (timeout = 30000)
+  public void testCheckDirsIOException() throws Throwable {
+    Path path = new Path("target", TestDiskChecker.class.getSimpleName());
+    File localDir = new File(path.toUri().getRawPath());
+    localDir.mkdir();
+    File localFile = new File(localDir, "test");
+    localFile.createNewFile();
+    File spyLocalDir = spy(localDir);
+    doReturn(localFile.toPath()).when(spyLocalDir).toPath();
+    try {
+      DiskChecker.checkDirs(spyLocalDir);
+      fail("Expected exception for I/O error");
+    } catch (DiskErrorException e) {
+      GenericTestUtils.assertExceptionContains("I/O error", e);
+      assertTrue(e.getCause() instanceof IOException);
+    } finally {
+      localFile.delete();
+      localDir.delete();
+    }
+  }
 }