HDFS-5474. Merge change r1541685 from trunk.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1541709 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -166,6 +166,9 @@ Release 2.3.0 - UNRELEASED
     HDFS-5425. Renaming underconstruction file with snapshots can make NN failure on 
     restart. (jing9 and Vinay)
 
+    HDFS-5474. Deletesnapshot can make Namenode in safemode on NN restarts. 
+    (Sathish via jing9)
+
     HDFS-5075. httpfs-config.sh calls out incorrect env script name
     (Timothy St. Clair via stevel)
 

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

@@ -6919,6 +6919,7 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       return; // Return previous response
     }
     boolean success = false;
+    BlocksMapUpdateInfo collectedBlocks = new BlocksMapUpdateInfo();
     writeLock();
     try {
       checkOperation(OperationCategory.WRITE);
@@ -6927,7 +6928,6 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
         checkOwner(pc, snapshotRoot);
       }
 
-      BlocksMapUpdateInfo collectedBlocks = new BlocksMapUpdateInfo();
       List<INode> removedINodes = new ChunkedArrayList<INode>();
       dir.writeLock();
       try {
@@ -6938,8 +6938,6 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
         dir.writeUnlock();
       }
       removedINodes.clear();
-      this.removeBlocks(collectedBlocks);
-      collectedBlocks.clear();
       getEditLog().logDeleteSnapshot(snapshotRoot, snapshotName,
           cacheEntry != null);
       success = true;
@@ -6948,7 +6946,10 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
       RetryCache.setState(cacheEntry, success);
     }
     getEditLog().logSync();
-    
+
+    removeBlocks(collectedBlocks);
+    collectedBlocks.clear();
+
     if (auditLog.isInfoEnabled() && isExternalInvocation()) {
       String rootPath = Snapshot.getSnapshotPath(snapshotRoot, snapshotName);
       logAuditEvent(true, "deleteSnapshot", rootPath, null, null);