HDFS-6945. BlockManager should remove a block from excessReplicateMap and decrement ExcessBlocks metric when the block is removed. (aajisaka)

(cherry picked from commit 18a91fe4df)

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

@@ -83,6 +83,9 @@ Release 2.8.0 - UNRELEASED
     HDFS-7997. The first non-existing xattr should also throw IOException.
     (zhouyingchao via yliu)
 
+    HDFS-6945. BlockManager should remove a block from excessReplicateMap and
+    decrement ExcessBlocks metric when the block is removed. (aajisaka)
+
 Release 2.7.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES

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

@@ -3354,8 +3354,7 @@ public void removeBlock(Block block) {
     // file already removes them from the block map below.
     block.setNumBytes(BlockCommand.NO_ACK);
     addToInvalidates(block);
-    corruptReplicas.removeFromCorruptReplicasMap(block);
-    blocksMap.removeBlock(block);
+    removeBlockFromMap(block);
     // Remove the block from pendingReplications and neededReplications
     pendingReplications.remove(block);
     neededReplications.remove(block, UnderReplicatedBlocks.LEVEL);
@@ -3531,11 +3530,30 @@ public int numCorruptReplicas(Block block) {
   }
 
   public void removeBlockFromMap(Block block) {
+    removeFromExcessReplicateMap(block);
     blocksMap.removeBlock(block);
     // If block is removed from blocksMap remove it from corruptReplicasMap
     corruptReplicas.removeFromCorruptReplicasMap(block);
   }
 
+  /**
+   * If a block is removed from blocksMap, remove it from excessReplicateMap.
+   */
+  private void removeFromExcessReplicateMap(Block block) {
+    for (DatanodeStorageInfo info : blocksMap.getStorages(block)) {
+      String uuid = info.getDatanodeDescriptor().getDatanodeUuid();
+      LightWeightLinkedSet<Block> excessReplicas = excessReplicateMap.get(uuid);
+      if (excessReplicas != null) {
+        if (excessReplicas.remove(block)) {
+          excessBlocksCount.decrementAndGet();
+          if (excessReplicas.isEmpty()) {
+            excessReplicateMap.remove(uuid);
+          }
+        }
+      }
+    }
+  }
+
   public int getCapacity() {
     return blocksMap.getCapacity();
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/metrics/TestNameNodeMetrics.java

@@ -273,12 +273,17 @@ public void testCorruptBlock() throws Exception {
   public void testExcessBlocks() throws Exception {
     Path file = getTestPath("testExcessBlocks");
     createFile(file, 100, (short)2);
-    long totalBlocks = 1;
     NameNodeAdapter.setReplication(namesystem, file.toString(), (short)1);
     updateMetrics();
     MetricsRecordBuilder rb = getMetrics(NS_METRICS);
-    assertGauge("ExcessBlocks", totalBlocks, rb);
+    assertGauge("ExcessBlocks", 1L, rb);
+
+    // verify ExcessBlocks metric is decremented and
+    // excessReplicateMap is cleared after deleting a file
     fs.delete(file, true);
+    rb = getMetrics(NS_METRICS);
+    assertGauge("ExcessBlocks", 0L, rb);
+    assertTrue(bm.excessReplicateMap.isEmpty());
   }
   
   /** Test to ensure metrics reflects missing blocks */