HDFS-13315. Add a test for the issue reported in HDFS-11481 which is fixed by HDFS-10997. Contributed by Yongjun Zhang.

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/snapshot/SnapshotDiff.java

@@ -106,6 +106,7 @@ public class SnapshotDiff extends Configured implements Tool {
     } catch (IOException e) {
       String[] content = e.getLocalizedMessage().split("\n");
       System.err.println("snapshotDiff: " + content[0]);
+      e.printStackTrace(System.err);
       return 1;
     }
     return 0;

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

@@ -121,6 +121,9 @@ import org.apache.hadoop.hdfs.protocol.ECBlockGroupStats;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicyInfo;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicyState;
 import org.apache.hadoop.hdfs.protocol.ReplicatedBlockStats;
+import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport;
+import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffReportEntry;
+import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffType;
 import org.apache.hadoop.hdfs.protocol.SystemErasureCodingPolicies;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
 import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
@@ -2354,4 +2357,38 @@ public class DFSTestUtil {
     }
     return closedFiles;
   }
+
+  /**
+   * Check the correctness of the snapshotDiff report.
+   * Make sure all items in the passed entries are in the snapshotDiff
+   * report.
+   */
+  public static void verifySnapshotDiffReport(DistributedFileSystem fs,
+      Path dir, String from, String to,
+      DiffReportEntry... entries) throws IOException {
+    SnapshotDiffReport report = fs.getSnapshotDiffReport(dir, from, to);
+    // reverse the order of from and to
+    SnapshotDiffReport inverseReport = fs
+        .getSnapshotDiffReport(dir, to, from);
+    LOG.info(report.toString());
+    LOG.info(inverseReport.toString() + "\n");
+
+    assertEquals(entries.length, report.getDiffList().size());
+    assertEquals(entries.length, inverseReport.getDiffList().size());
+
+    for (DiffReportEntry entry : entries) {
+      if (entry.getType() == DiffType.MODIFY) {
+        assertTrue(report.getDiffList().contains(entry));
+        assertTrue(inverseReport.getDiffList().contains(entry));
+      } else if (entry.getType() == DiffType.DELETE) {
+        assertTrue(report.getDiffList().contains(entry));
+        assertTrue(inverseReport.getDiffList().contains(
+            new DiffReportEntry(DiffType.CREATE, entry.getSourcePath())));
+      } else if (entry.getType() == DiffType.CREATE) {
+        assertTrue(report.getDiffList().contains(entry));
+        assertTrue(inverseReport.getDiffList().contains(
+            new DiffReportEntry(DiffType.DELETE, entry.getSourcePath())));
+      }
+    }
+  }
 }

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

@@ -75,6 +75,8 @@ import org.apache.hadoop.hdfs.protocol.EncryptionZone;
 import org.apache.hadoop.hdfs.protocol.HdfsFileStatus;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
 import org.apache.hadoop.hdfs.protocol.HdfsConstants.SafeModeAction;
+import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffReportEntry;
+import org.apache.hadoop.hdfs.protocol.SnapshotDiffReport.DiffType;
 import org.apache.hadoop.hdfs.server.namenode.EncryptionFaultInjector;
 import org.apache.hadoop.hdfs.server.namenode.EncryptionZoneManager;
 import org.apache.hadoop.hdfs.server.namenode.FSImageTestUtil;
@@ -148,6 +150,7 @@ import javax.xml.parsers.SAXParser;
 import javax.xml.parsers.SAXParserFactory;
 
 public class TestEncryptionZones {
+  static final Logger LOG = Logger.getLogger(TestEncryptionZones.class);
 
   protected Configuration conf;
   private FileSystemTestHelper fsHelper;
@@ -1495,6 +1498,44 @@ public class TestEncryptionZones {
         contents, DFSTestUtil.readFile(fs, snapshottedZoneFile));
   }
 
+  /**
+   * Check the correctness of the diff reports.
+   */
+  private void verifyDiffReport(Path dir, String from, String to,
+      DiffReportEntry... entries) throws IOException {
+    DFSTestUtil.verifySnapshotDiffReport(fs, dir, from, to, entries);
+  }
+
+  /**
+   * Test correctness of snapshotDiff for encryption zone.
+   * snapshtoDiff should work when the path parameter is prefixed with
+   * /.reserved/raw for path that's both snapshottable and encryption zone.
+   */
+  @Test
+  public void testSnapshotDiffOnEncryptionZones() throws Exception {
+    final String TEST_KEY2 = "testkey2";
+    DFSTestUtil.createKey(TEST_KEY2, cluster, conf);
+
+    final int len = 8196;
+    final Path zone = new Path("/zone");
+    final Path rawZone = new Path("/.reserved/raw/zone");
+    final Path zoneFile = new Path(zone, "zoneFile");
+    fsWrapper.mkdir(zone, FsPermission.getDirDefault(), true);
+    dfsAdmin.allowSnapshot(zone);
+    dfsAdmin.createEncryptionZone(zone, TEST_KEY, NO_TRASH);
+    DFSTestUtil.createFile(fs, zoneFile, len, (short) 1, 0xFEED);
+    fs.createSnapshot(zone, "snap1");
+    fsWrapper.delete(zoneFile, true);
+    fs.createSnapshot(zone, "snap2");
+    verifyDiffReport(zone, "snap1", "snap2",
+        new DiffReportEntry(DiffType.MODIFY, DFSUtil.string2Bytes("")),
+        new DiffReportEntry(DiffType.DELETE, DFSUtil.string2Bytes("zoneFile")));
+
+    verifyDiffReport(rawZone, "snap1", "snap2",
+        new DiffReportEntry(DiffType.MODIFY, DFSUtil.string2Bytes("")),
+        new DiffReportEntry(DiffType.DELETE, DFSUtil.string2Bytes("zoneFile")));
+  }
+
   /**
    * Verify symlinks can be created in encryption zones and that
    * they function properly when the target is in the same

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

@@ -194,30 +194,7 @@ public class TestSnapshotDiffReport {
    */
   private void verifyDiffReport(Path dir, String from, String to,
       DiffReportEntry... entries) throws IOException {
-    SnapshotDiffReport report = hdfs.getSnapshotDiffReport(dir, from, to);
+    DFSTestUtil.verifySnapshotDiffReport(hdfs, dir, from, to, entries);
-    // reverse the order of from and to
-    SnapshotDiffReport inverseReport = hdfs
-        .getSnapshotDiffReport(dir, to, from);
-    LOG.info(report.toString());
-    LOG.info(inverseReport.toString() + "\n");
-
-    assertEquals(entries.length, report.getDiffList().size());
-    assertEquals(entries.length, inverseReport.getDiffList().size());
-
-    for (DiffReportEntry entry : entries) {
-      if (entry.getType() == DiffType.MODIFY) {
-        assertTrue(report.getDiffList().contains(entry));
-        assertTrue(inverseReport.getDiffList().contains(entry));
-      } else if (entry.getType() == DiffType.DELETE) {
-        assertTrue(report.getDiffList().contains(entry));
-        assertTrue(inverseReport.getDiffList().contains(
-            new DiffReportEntry(DiffType.CREATE, entry.getSourcePath())));
-      } else if (entry.getType() == DiffType.CREATE) {
-        assertTrue(report.getDiffList().contains(entry));
-        assertTrue(inverseReport.getDiffList().contains(
-            new DiffReportEntry(DiffType.DELETE, entry.getSourcePath())));
-      }
-    }
   }
 
   /**