HDFS-8133. Improve readability of deleted block check (Daryn Sharp via Colin P. McCabe)

(cherry picked from commit 997408eaaceef20b053ee7344468e28cb9a1379b)

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

@@ -134,6 +134,9 @@ Release 2.8.0 - UNRELEASED
 
     HDFS-8169. Move LocatedBlocks and related classes to hdfs-client. (wheat9)
 
+    HDFS-8133. Improve readability of deleted block check (Daryn Sharp via
+    Colin P. McCabe)
+
   OPTIMIZATIONS
 
     HDFS-8026. Trace FSOutputSummer#writeChecksumChunks rather than

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

@@ -89,6 +89,10 @@ public class BlockInfoContiguous extends Block
     this.bc = bc;
   }
 
+  public boolean isDeleted() {
+    return (bc == null);
+  }
+
   public DatanodeDescriptor getDatanode(int index) {
     DatanodeStorageInfo storage = getStorageInfo(index);
     return storage == null ? null : storage.getDatanodeDescriptor();

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

@@ -1165,13 +1165,14 @@ public class BlockManager {
       DatanodeStorageInfo storageInfo,
       DatanodeDescriptor node) throws IOException {
 
-    BlockCollection bc = b.corrupted.getBlockCollection();
-    if (bc == null) {
+    if (b.corrupted.isDeleted()) {
       blockLog.info("BLOCK markBlockAsCorrupt: {} cannot be marked as" +
           " corrupt as it does not belong to any file", b);
       addToInvalidates(b.corrupted, node);
       return;
     } 
+    short expectedReplicas =
+        b.corrupted.getBlockCollection().getBlockReplication();
 
     // Add replica to the data-node if it is not already there
     if (storageInfo != null) {
@@ -1183,13 +1184,13 @@ public class BlockManager {
         b.reasonCode);
 
     NumberReplicas numberOfReplicas = countNodes(b.stored);
-    boolean hasEnoughLiveReplicas = numberOfReplicas.liveReplicas() >= bc
-        .getBlockReplication();
+    boolean hasEnoughLiveReplicas = numberOfReplicas.liveReplicas() >=
+        expectedReplicas;
     boolean minReplicationSatisfied =
         numberOfReplicas.liveReplicas() >= minReplication;
     boolean hasMoreCorruptReplicas = minReplicationSatisfied &&
         (numberOfReplicas.liveReplicas() + numberOfReplicas.corruptReplicas()) >
-        bc.getBlockReplication();
+        expectedReplicas;
     boolean corruptedDuringWrite = minReplicationSatisfied &&
         (b.stored.getGenerationStamp() > b.corrupted.getGenerationStamp());
     // case 1: have enough number of live replicas
@@ -2512,7 +2513,7 @@ public class BlockManager {
     } else {
       storedBlock = block;
     }
-    if (storedBlock == null || storedBlock.getBlockCollection() == null) {
+    if (storedBlock == null || storedBlock.isDeleted()) {
       // If this block does not belong to anyfile, then we are done.
       blockLog.info("BLOCK* addStoredBlock: {} on {} size {} but it does not" +
           " belong to any file", block, node, block.getNumBytes());
@@ -2797,8 +2798,7 @@ public class BlockManager {
    * what happened with it.
    */
   private MisReplicationResult processMisReplicatedBlock(BlockInfoContiguous block) {
-    BlockCollection bc = block.getBlockCollection();
-    if (bc == null) {
+    if (block.isDeleted()) {
       // block does not belong to any file
       addToInvalidates(block);
       return MisReplicationResult.INVALID;
@@ -2809,7 +2809,8 @@ public class BlockManager {
       return MisReplicationResult.UNDER_CONSTRUCTION;
     }
     // calculate current replication
-    short expectedReplication = bc.getBlockReplication();
+    short expectedReplication =
+        block.getBlockCollection().getBlockReplication();
     NumberReplicas num = countNodes(block);
     int numCurrentReplica = num.liveReplicas();
     // add to under-replicated queue if need to be

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

@@ -193,7 +193,7 @@ class BlocksMap {
     boolean removed = node.removeBlock(info);
 
     if (info.getDatanode(0) == null     // no datanodes left
-              && info.getBlockCollection() == null) {  // does not belong to a file
+              && info.isDeleted()) {  // does not belong to a file
       blocks.remove(b);  // remove block from the map
     }
     return removed;

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

@@ -4260,13 +4260,12 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
       // this method to add a CloseOp to the edit log for an already deleted
       // file (See HDFS-6825).
       //
-      BlockCollection blockCollection = storedBlock.getBlockCollection();
-      if (blockCollection == null) {
+      if (storedBlock.isDeleted()) {
         throw new IOException("The blockCollection of " + storedBlock
             + " is null, likely because the file owning this block was"
             + " deleted and the block removal is delayed");
       }
-      INodeFile iFile = ((INode)blockCollection).asFile();
+      INodeFile iFile = ((INode)storedBlock.getBlockCollection()).asFile();
       if (isFileDeleted(iFile)) {
         throw new FileNotFoundException("File not found: "
             + iFile.getFullPathName() + ", likely due to delayed block"

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/blockmanagement/TestBlockInfo.java

@@ -34,6 +34,7 @@ import org.apache.hadoop.hdfs.server.common.GenerationStamp;
 import org.apache.hadoop.hdfs.server.protocol.DatanodeStorage;
 import org.junit.Assert;
 import org.junit.Test;
+import org.mockito.Mockito;
 
 /**
  * This class provides tests for BlockInfo class, which is used in BlocksMap.
@@ -46,6 +47,15 @@ public class TestBlockInfo {
   private static final Log LOG = LogFactory
       .getLog("org.apache.hadoop.hdfs.TestBlockInfo");
 
+  @Test
+  public void testIsDeleted() {
+    BlockInfoContiguous blockInfo = new BlockInfoContiguous((short) 3);
+    BlockCollection bc = Mockito.mock(BlockCollection.class);
+    blockInfo.setBlockCollection(bc);
+    Assert.assertFalse(blockInfo.isDeleted());
+    blockInfo.setBlockCollection(null);
+    Assert.assertTrue(blockInfo.isDeleted());
+  }
 
   @Test
   public void testAddStorage() throws Exception {