HDFS-7503. Namenode restart after large deletions can cause slow processReport (Arpit Agarwal)

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

@@ -593,6 +593,9 @@ Release 2.6.1 - UNRELEASED
     HDFS-7489. Incorrect locking in FsVolumeList#checkDirs can hang datanodes
     (Noah Lorang via Colin P. McCabe)
 
+    HDFS-7503. Namenode restart after large deletions can cause slow
+    processReport. (Arpit Agarwal)
+
 Release 2.6.0 - 2014-11-18
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java

@@ -1785,6 +1785,8 @@ public class BlockManager {
     final long startTime = Time.now(); //after acquiring write lock
     final long endTime;
     DatanodeDescriptor node;
+    Collection<Block> invalidatedBlocks = null;
+
     try {
       node = datanodeManager.getDatanode(nodeID);
       if (node == null || !node.isAlive) {
@@ -1813,7 +1815,7 @@ public class BlockManager {
         // ordinary block reports.  This shortens restart times.
         processFirstBlockReport(storageInfo, newReport);
       } else {
-        processReport(storageInfo, newReport);
+        invalidatedBlocks = processReport(storageInfo, newReport);
       }
       
       // Now that we have an up-to-date block report, we know that any
@@ -1832,6 +1834,14 @@ public class BlockManager {
       namesystem.writeUnlock();
     }
 
+    if (invalidatedBlocks != null) {
+      for (Block b : invalidatedBlocks) {
+        blockLog.info("BLOCK* processReport: " + b + " on " + node
+                          + " size " + b.getNumBytes()
+                          + " does not belong to any file");
+      }
+    }
+
     // Log the block report processing stats from Namenode perspective
     final NameNodeMetrics metrics = NameNode.getNameNodeMetrics();
     if (metrics != null) {
@@ -1875,8 +1885,9 @@ public class BlockManager {
     }
   }
   
-  private void processReport(final DatanodeStorageInfo storageInfo,
-                             final BlockListAsLongs report) throws IOException {
+  private Collection<Block> processReport(
+      final DatanodeStorageInfo storageInfo,
+      final BlockListAsLongs report) throws IOException {
     // Normal case:
     // Modify the (block-->datanode) map, according to the difference
     // between the old and new block report.
@@ -1907,14 +1918,13 @@ public class BlockManager {
           + " of " + numBlocksLogged + " reported.");
     }
     for (Block b : toInvalidate) {
-      blockLog.info("BLOCK* processReport: "
-          + b + " on " + node + " size " + b.getNumBytes()
-          + " does not belong to any file");
       addToInvalidates(b, node);
     }
     for (BlockToMarkCorrupt b : toCorrupt) {
       markBlockAsCorrupt(b, storageInfo, node);
     }
+
+    return toInvalidate;
   }
 
   /**