From 9d891f08c28d1acdd0c1527efb784972f739ad1b Mon Sep 17 00:00:00 2001
From: S O'Donnell <sodonnell@cloudera.com>
Date: Thu, 18 Jun 2020 12:26:22 +0100
Subject: [PATCH] HDFS-15406. Improve the speed of Datanode Block Scan.
 Contributed by hemanthboyina

(cherry picked from commit 123777823edc98553fcef61f1913ab6e4cd5aa9a)
---
 .../hdfs/server/datanode/fsdataset/impl/FsVolumeImpl.java     | 4 +++-
 .../apache/hadoop/hdfs/server/datanode/DataNodeTestUtils.java | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsVolumeImpl.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsVolumeImpl.java
index 5a8229aee14..8810bfc2ac0 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsVolumeImpl.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsVolumeImpl.java
@@ -133,6 +133,7 @@ public class FsVolumeImpl implements FsVolumeSpi {
   protected volatile long configuredCapacity;
   private final FileIoProvider fileIoProvider;
   private final DataNodeVolumeMetrics metrics;
+  private URI baseURI;
 
   /**
    * Per-volume worker pool that processes new blocks to cache.
@@ -175,6 +176,7 @@ public class FsVolumeImpl implements FsVolumeSpi {
       File parent = currentDir.getParentFile();
       cacheExecutor = initializeCacheExecutor(parent);
       this.metrics = DataNodeVolumeMetrics.create(conf, parent.getPath());
+      this.baseURI = new File(currentDir.getParent()).toURI();
     } else {
       cacheExecutor = null;
       this.metrics = null;
@@ -500,7 +502,7 @@ public class FsVolumeImpl implements FsVolumeSpi {
 
   @Override
   public URI getBaseURI() {
-    return new File(currentDir.getParent()).toURI();
+    return baseURI;
   }
 
   @Override
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/DataNodeTestUtils.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/DataNodeTestUtils.java
index bb78cbce304..6201624b798 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/DataNodeTestUtils.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/DataNodeTestUtils.java
@@ -239,7 +239,7 @@ public class DataNodeTestUtils {
     try (FsDatasetSpi.FsVolumeReferences volumes = dn.getFSDataset()
         .getFsVolumeReferences()) {
       for (FsVolumeSpi vol : volumes) {
-        if (vol.getBaseURI().equals(basePath.toURI())) {
+        if (new File(vol.getBaseURI()).equals(basePath)) {
           return (FsVolumeImpl) vol;
         }
       }