From b040eb91c7d2625aa0864a7392830d83670fb51e Mon Sep 17 00:00:00 2001
From: Siyao Meng <50227127+smengcl@users.noreply.github.com>
Date: Mon, 12 Aug 2019 17:26:20 -0700
Subject: [PATCH] HDFS-14148. HDFS OIV ReverseXML SnapshotSection parser throws
 exception when there are more than one snapshottable directory (#1274)
 Contributed by Siyao Meng.

(cherry picked from commit c92b49876a078ce7fb4e2a852e315de5b6410082)
(cherry picked from commit c5f433b11fe7409cb59d86e410bc2f7135cde7ca)
---
 .../offlineImageViewer/OfflineImageReconstructor.java  |  8 +++++---
 .../offlineImageViewer/TestOfflineImageViewer.java     | 10 ++++++++++
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/OfflineImageReconstructor.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/OfflineImageReconstructor.java
index 7d0a4924f13..65abc6f41cb 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/OfflineImageReconstructor.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/OfflineImageReconstructor.java
@@ -1353,9 +1353,11 @@ class OfflineImageReconstructor {
         if (sd == null) {
           break;
         }
-        Long dir = sd.removeChildLong(SNAPSHOT_SECTION_DIR);
-        sd.verifyNoRemainingKeys("<dir>");
-        bld.addSnapshottableDir(dir);
+        Long dir;
+        while ((dir = sd.removeChildLong(SNAPSHOT_SECTION_DIR)) != null) {
+          // Add all snapshottable directories, one by one
+          bld.addSnapshottableDir(dir);
+        }
       }
       header.verifyNoRemainingKeys("SnapshotSection");
       bld.build().writeDelimitedTo(out);
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/TestOfflineImageViewer.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/TestOfflineImageViewer.java
index 2fdba752416..8a3e3d0990b 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/TestOfflineImageViewer.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/offlineImageViewer/TestOfflineImageViewer.java
@@ -251,6 +251,16 @@ public class TestOfflineImageViewer {
       hdfs.truncate(file1, 1);
       writtenFiles.put(file1.toString(), hdfs.getFileStatus(file1));
 
+      // HDFS-14148: Create a second snapshot-enabled directory. This can cause
+      // TestOfflineImageViewer#testReverseXmlRoundTrip to fail before the patch
+      final Path snapshotDir2 = new Path("/snapshotDir2");
+      hdfs.mkdirs(snapshotDir2);
+      // Simply enable snapshot on it, no need to create one
+      hdfs.allowSnapshot(snapshotDir2);
+      dirCount++;
+      writtenFiles.put(snapshotDir2.toString(),
+          hdfs.getFileStatus(snapshotDir2));
+
       // Set XAttrs so the fsimage contains XAttr ops
       final Path xattr = new Path("/xattr");
       hdfs.mkdirs(xattr);