From 9b1e532c0b78c18f281b3433ebd96e6e440d54a5 Mon Sep 17 00:00:00 2001
From: "Doroszlai, Attila" <adoroszlai@apache.org>
Date: Mon, 24 Mar 2025 10:04:40 +0100
Subject: [PATCH 1/5] move storageType to StorageVolume

---
 .../container/common/volume/StorageVolume.java    | 10 +++++-----
 .../ozone/container/common/volume/VolumeInfo.java | 15 ---------------
 2 files changed, 5 insertions(+), 20 deletions(-)

diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java
index 6056bd9b37d3..0f10eeb5c035 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java
@@ -118,6 +118,7 @@ public enum VolumeState {
   private final ConfigurationSource conf;
   private final DatanodeConfiguration dnConf;
 
+  private final StorageType storageType;
   private final File storageDir;
   private String workingDirName;
   private File tmpDir;
@@ -139,12 +140,12 @@ public enum VolumeState {
   private int healthCheckFileSize;
 
   protected StorageVolume(Builder<?> b) throws IOException {
+    storageType = b.storageType;
     if (!b.failedVolume) {
       StorageLocation location = StorageLocation.parse(b.volumeRootStr);
       storageDir = new File(location.getUri().getPath(), b.storageDirStr);
       this.volumeInfo = Optional.of(
               new VolumeInfo.Builder(b.volumeRootStr, b.conf)
-          .storageType(b.storageType)
           .usageCheckFactory(b.usageCheckFactory)
           .build());
       this.volumeSet = b.volumeSet;
@@ -375,7 +376,7 @@ public abstract static class Builder<T extends Builder<T>> {
     private final String volumeRootStr;
     private String storageDirStr;
     private ConfigurationSource conf;
-    private StorageType storageType;
+    private StorageType storageType = StorageType.DEFAULT;
     private SpaceUsageCheckFactory usageCheckFactory;
     private VolumeSet volumeSet;
     private boolean failedVolume = false;
@@ -395,7 +396,7 @@ public T conf(ConfigurationSource config) {
     }
 
     public T storageType(StorageType st) {
-      this.storageType = st;
+      this.storageType = Objects.requireNonNull(st, "storageType == null");
       return this.getThis();
     }
 
@@ -491,8 +492,7 @@ public VolumeSet getVolumeSet() {
   }
 
   public StorageType getStorageType() {
-    return volumeInfo.map(VolumeInfo::getStorageType)
-            .orElse(StorageType.DEFAULT);
+    return storageType;
   }
 
   public String getStorageID() {
diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfo.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfo.java
index a25676bf5c73..d0363915297c 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfo.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfo.java
@@ -20,7 +20,6 @@
 import com.google.common.annotations.VisibleForTesting;
 import java.io.File;
 import java.io.IOException;
-import org.apache.hadoop.fs.StorageType;
 import org.apache.hadoop.hdds.conf.ConfigurationSource;
 import org.apache.hadoop.hdds.fs.SpaceUsageCheckFactory;
 import org.apache.hadoop.hdds.fs.SpaceUsageCheckParams;
@@ -90,7 +89,6 @@ public final class VolumeInfo {
   private static final Logger LOG = LoggerFactory.getLogger(VolumeInfo.class);
 
   private final String rootDir;
-  private final StorageType storageType;
 
   // Space usage calculator
   private final VolumeUsage usage;
@@ -102,18 +100,12 @@ public static class Builder {
     private final ConfigurationSource conf;
     private final String rootDir;
     private SpaceUsageCheckFactory usageCheckFactory;
-    private StorageType storageType;
 
     public Builder(String root, ConfigurationSource config) {
       this.rootDir = root;
       this.conf = config;
     }
 
-    public Builder storageType(StorageType st) {
-      this.storageType = st;
-      return this;
-    }
-
     public Builder usageCheckFactory(SpaceUsageCheckFactory factory) {
       this.usageCheckFactory = factory;
       return this;
@@ -136,9 +128,6 @@ private VolumeInfo(Builder b) throws IOException {
       throw new IOException("Unable to create the volume root dir at " + root);
     }
 
-    this.storageType = (b.storageType != null ?
-        b.storageType : StorageType.DEFAULT);
-
     SpaceUsageCheckFactory usageCheckFactory = b.usageCheckFactory;
     if (usageCheckFactory == null) {
       usageCheckFactory = SpaceUsageCheckFactory.create(b.conf);
@@ -173,10 +162,6 @@ public String getRootDir() {
     return this.rootDir;
   }
 
-  public StorageType getStorageType() {
-    return this.storageType;
-  }
-
   /**
    * Only for testing. Do not use otherwise.
    */

From 503d985867b60c34ce2909b7c8eb1f66a63ad7c8 Mon Sep 17 00:00:00 2001
From: "Doroszlai, Attila" <adoroszlai@apache.org>
Date: Mon, 24 Mar 2025 10:09:37 +0100
Subject: [PATCH 2/5] move String rootDir to StorageVolume

---
 .../ozone/container/common/volume/MutableVolumeSet.java  | 5 ++---
 .../ozone/container/common/volume/StorageVolume.java     | 6 ++++--
 .../hadoop/ozone/container/common/volume/VolumeInfo.java | 9 +--------
 3 files changed, 7 insertions(+), 13 deletions(-)

diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/MutableVolumeSet.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/MutableVolumeSet.java
index f65d89e4cfe8..76379fa93f87 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/MutableVolumeSet.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/MutableVolumeSet.java
@@ -470,11 +470,10 @@ public StorageLocationReport[] getStorageReport() {
         long capacity = 0;
         long committed = 0;
         long spare = 0;
-        String rootDir = "";
+        String rootDir = volume.getVolumeRootDir();
         failed = true;
         if (volumeInfo.isPresent()) {
           try {
-            rootDir = volumeInfo.get().getRootDir();
             SpaceUsageSource usage = volumeInfo.get().getCurrentUsage();
             scmUsed = usage.getUsedSpace();
             remaining = usage.getAvailable();
@@ -485,7 +484,7 @@ public StorageLocationReport[] getStorageReport() {
             failed = false;
           } catch (UncheckedIOException ex) {
             LOG.warn("Failed to get scmUsed and remaining for container " +
-                    "storage location {}", volumeInfo.get().getRootDir(), ex);
+                    "storage location {}", rootDir, ex);
             // reset scmUsed and remaining if df/du failed.
             scmUsed = 0;
             remaining = 0;
diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java
index 0f10eeb5c035..65810138eba8 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java
@@ -119,6 +119,7 @@ public enum VolumeState {
   private final DatanodeConfiguration dnConf;
 
   private final StorageType storageType;
+  private final String volumeRoot;
   private final File storageDir;
   private String workingDirName;
   private File tmpDir;
@@ -141,8 +142,9 @@ public enum VolumeState {
 
   protected StorageVolume(Builder<?> b) throws IOException {
     storageType = b.storageType;
+    volumeRoot = b.volumeRootStr;
     if (!b.failedVolume) {
-      StorageLocation location = StorageLocation.parse(b.volumeRootStr);
+      StorageLocation location = StorageLocation.parse(volumeRoot);
       storageDir = new File(location.getUri().getPath(), b.storageDirStr);
       this.volumeInfo = Optional.of(
               new VolumeInfo.Builder(b.volumeRootStr, b.conf)
@@ -444,7 +446,7 @@ public StorageType getStorageType() {
   }
 
   public String getVolumeRootDir() {
-    return volumeInfo.map(VolumeInfo::getRootDir).orElse(null);
+    return volumeRoot;
   }
 
   public SpaceUsageSource getCurrentUsage() {
diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfo.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfo.java
index d0363915297c..e0c01f38d0c6 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfo.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfo.java
@@ -88,8 +88,6 @@ public final class VolumeInfo {
 
   private static final Logger LOG = LoggerFactory.getLogger(VolumeInfo.class);
 
-  private final String rootDir;
-
   // Space usage calculator
   private final VolumeUsage usage;
 
@@ -118,8 +116,7 @@ public VolumeInfo build() throws IOException {
 
   private VolumeInfo(Builder b) throws IOException {
 
-    this.rootDir = b.rootDir;
-    File root = new File(this.rootDir);
+    File root = new File(b.rootDir);
 
     boolean succeeded = root.isDirectory() || root.mkdirs();
 
@@ -158,10 +155,6 @@ void shutdownUsageThread() {
     usage.shutdown();
   }
 
-  public String getRootDir() {
-    return this.rootDir;
-  }
-
   /**
    * Only for testing. Do not use otherwise.
    */

From 0350a99a5b9012bb4c26be0628d396addbba7428 Mon Sep 17 00:00:00 2001
From: "Doroszlai, Attila" <adoroszlai@apache.org>
Date: Mon, 24 Mar 2025 10:30:39 +0100
Subject: [PATCH 3/5] remove VolumeInfo

---
 .../container/common/volume/DbVolume.java     |   2 +-
 .../container/common/volume/HddsVolume.java   |   2 +-
 .../common/volume/MutableVolumeSet.java       |   4 +-
 .../common/volume/StorageVolume.java          |  49 +++--
 .../container/common/volume/VolumeInfo.java   | 169 ------------------
 .../container/common/volume/VolumeUsage.java  |  59 +++++-
 .../volume/TestReservedVolumeSpace.java       |  14 +-
 .../common/volume/TestVolumeSet.java          |   4 +-
 .../hadoop/ozone/UniformDatanodesFactory.java |   2 +-
 9 files changed, 103 insertions(+), 202 deletions(-)
 delete mode 100644 hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfo.java

diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/DbVolume.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/DbVolume.java
index f7a99b9b1ee9..0f188e53b137 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/DbVolume.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/DbVolume.java
@@ -55,7 +55,7 @@ protected DbVolume(Builder b) throws IOException {
     super(b);
 
     this.hddsDbStorePathMap = new HashMap<>();
-    if (!b.getFailedVolume() && getVolumeInfo().isPresent()) {
+    if (!b.getFailedVolume()) {
       LOG.info("Creating DbVolume: {} of storage type: {}, {}",
               getStorageDir(), b.getStorageType(),
               getCurrentUsage());
diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/HddsVolume.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/HddsVolume.java
index 5513363d2a60..d355908e5e91 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/HddsVolume.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/HddsVolume.java
@@ -119,7 +119,7 @@ public HddsVolume build() throws IOException {
   private HddsVolume(Builder b) throws IOException {
     super(b);
 
-    if (!b.getFailedVolume() && getVolumeInfo().isPresent()) {
+    if (!b.getFailedVolume()) {
       this.setState(VolumeState.NOT_INITIALIZED);
       ConfigurationSource conf = getConf();
       int[] intervals = conf.getInts(OZONE_DATANODE_IO_METRICS_PERCENTILES_INTERVALS_SECONDS_KEY);
diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/MutableVolumeSet.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/MutableVolumeSet.java
index 76379fa93f87..29cc05fcee70 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/MutableVolumeSet.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/MutableVolumeSet.java
@@ -277,7 +277,7 @@ public void checkVolumeAsync(StorageVolume volume) {
   }
 
   public void refreshAllVolumeUsage() {
-    volumeMap.forEach((k, v) -> v.refreshVolumeInfo());
+    volumeMap.forEach((k, v) -> v.refreshVolumeUsage());
   }
 
   /**
@@ -464,7 +464,7 @@ public StorageLocationReport[] getStorageReport() {
       StorageVolume volume;
       for (Map.Entry<String, StorageVolume> entry : volumeMap.entrySet()) {
         volume = entry.getValue();
-        Optional<VolumeInfo> volumeInfo = volume.getVolumeInfo();
+        Optional<VolumeUsage> volumeInfo = volume.getVolumeInfo();
         long scmUsed = 0;
         long remaining = 0;
         long capacity = 0;
diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java
index 65810138eba8..28c062e43252 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java
@@ -37,6 +37,7 @@
 import org.apache.hadoop.fs.StorageType;
 import org.apache.hadoop.hdds.conf.ConfigurationSource;
 import org.apache.hadoop.hdds.fs.SpaceUsageCheckFactory;
+import org.apache.hadoop.hdds.fs.SpaceUsageCheckParams;
 import org.apache.hadoop.hdds.fs.SpaceUsageSource;
 import org.apache.hadoop.hdfs.server.datanode.StorageLocation;
 import org.apache.hadoop.hdfs.server.datanode.checker.Checkable;
@@ -125,7 +126,7 @@ public enum VolumeState {
   private File tmpDir;
   private File diskCheckDir;
 
-  private final Optional<VolumeInfo> volumeInfo;
+  private final Optional<VolumeUsage> volumeUsage;
 
   private final VolumeSet volumeSet;
 
@@ -146,10 +147,8 @@ protected StorageVolume(Builder<?> b) throws IOException {
     if (!b.failedVolume) {
       StorageLocation location = StorageLocation.parse(volumeRoot);
       storageDir = new File(location.getUri().getPath(), b.storageDirStr);
-      this.volumeInfo = Optional.of(
-              new VolumeInfo.Builder(b.volumeRootStr, b.conf)
-          .usageCheckFactory(b.usageCheckFactory)
-          .build());
+      SpaceUsageCheckParams checkParams = getSpaceUsageCheckParams(b);
+      volumeUsage = Optional.of(new VolumeUsage(checkParams, b.conf));
       this.volumeSet = b.volumeSet;
       this.state = VolumeState.NOT_INITIALIZED;
       this.clusterID = b.clusterID;
@@ -164,7 +163,7 @@ protected StorageVolume(Builder<?> b) throws IOException {
       this.healthCheckFileSize = dnConf.getVolumeHealthCheckFileSize();
     } else {
       storageDir = new File(b.volumeRootStr);
-      this.volumeInfo = Optional.empty();
+      volumeUsage = Optional.empty();
       this.volumeSet = null;
       this.storageID = UUID.randomUUID().toString();
       this.state = VolumeState.FAILED;
@@ -449,8 +448,9 @@ public String getVolumeRootDir() {
     return volumeRoot;
   }
 
+  /** Get current usage of the volume. */
   public SpaceUsageSource getCurrentUsage() {
-    return volumeInfo.map(VolumeInfo::getCurrentUsage)
+    return volumeUsage.map(VolumeUsage::getCurrentUsage)
         .orElse(SpaceUsageSource.UNKNOWN);
   }
 
@@ -471,21 +471,22 @@ public File getDiskCheckDir() {
     return this.diskCheckDir;
   }
 
-  public void refreshVolumeInfo() {
-    volumeInfo.ifPresent(VolumeInfo::refreshNow);
+  public void refreshVolumeUsage() {
+    volumeUsage.ifPresent(VolumeUsage::refreshNow);
   }
 
-  public Optional<VolumeInfo> getVolumeInfo() {
-    return this.volumeInfo;
+  /** @see #getCurrentUsage() */
+  public Optional<VolumeUsage> getVolumeInfo() {
+    return volumeUsage;
   }
 
   public void incrementUsedSpace(long usedSpace) {
-    volumeInfo.ifPresent(volInfo -> volInfo
+    volumeUsage.ifPresent(usage -> usage
             .incrementUsedSpace(usedSpace));
   }
 
   public void decrementUsedSpace(long reclaimedSpace) {
-    volumeInfo.ifPresent(volInfo -> volInfo
+    volumeUsage.ifPresent(usage -> usage
             .decrementUsedSpace(reclaimedSpace));
   }
 
@@ -539,12 +540,12 @@ public DatanodeConfiguration getDatanodeConfig() {
 
   public void failVolume() {
     setState(VolumeState.FAILED);
-    volumeInfo.ifPresent(VolumeInfo::shutdownUsageThread);
+    volumeUsage.ifPresent(VolumeUsage::shutdown);
   }
 
   public void shutdown() {
     setState(VolumeState.NON_EXISTENT);
-    volumeInfo.ifPresent(VolumeInfo::shutdownUsageThread);
+    volumeUsage.ifPresent(VolumeUsage::shutdown);
     cleanTmpDiskCheckDir();
   }
 
@@ -681,4 +682,22 @@ public boolean equals(Object other) {
   public String toString() {
     return getStorageDir().toString();
   }
+
+  private static SpaceUsageCheckParams getSpaceUsageCheckParams(Builder b) throws IOException {
+    File root = new File(b.volumeRootStr);
+
+    boolean succeeded = root.isDirectory() || root.mkdirs();
+
+    if (!succeeded) {
+      LOG.error("Unable to create the volume root dir at : {}", root);
+      throw new IOException("Unable to create the volume root dir at " + root);
+    }
+
+    SpaceUsageCheckFactory usageCheckFactory = b.usageCheckFactory;
+    if (usageCheckFactory == null) {
+      usageCheckFactory = SpaceUsageCheckFactory.create(b.conf);
+    }
+
+    return usageCheckFactory.paramsFor(root);
+  }
 }
diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfo.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfo.java
deleted file mode 100644
index e0c01f38d0c6..000000000000
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfo.java
+++ /dev/null
@@ -1,169 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.hadoop.ozone.container.common.volume;
-
-import com.google.common.annotations.VisibleForTesting;
-import java.io.File;
-import java.io.IOException;
-import org.apache.hadoop.hdds.conf.ConfigurationSource;
-import org.apache.hadoop.hdds.fs.SpaceUsageCheckFactory;
-import org.apache.hadoop.hdds.fs.SpaceUsageCheckParams;
-import org.apache.hadoop.hdds.fs.SpaceUsageSource;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-/**
- * Stores information about a disk/volume.
- *
- * Since we have a reserved space for each volume for other usage,
- * let's clarify the space values a bit here:
- * - used: hdds actual usage.
- * - avail: remaining space for hdds usage.
- * - reserved: total space for other usage.
- * - capacity: total space for hdds usage.
- * - other: space used by other service consuming the same volume.
- * - fsAvail: reported remaining space from local fs.
- * - fsUsed: reported total used space from local fs.
- * - fsCapacity: reported total capacity from local fs.
- * - minVolumeFreeSpace (mvfs) : determines the free space for closing
-     containers.This is like adding a few reserved bytes to reserved space.
-     Dn's will send close container action to SCM at this limit, and it is
-     configurable.
-
- *
- * <pre>
- * {@code
- * |----used----|   (avail)   |++mvfs++|++++reserved+++++++|
- * |<-     capacity                  ->|
- *              |     fsAvail      |-------other-----------|
- * |<-                   fsCapacity                      ->|
- * }</pre>
- * <pre>
- * What we could directly get from local fs:
- *     fsCapacity, fsAvail, (fsUsed = fsCapacity - fsAvail)
- * We could get from config:
- *     reserved
- * Get from cmd line:
- *     used: from cmd 'du' (by default)
- * Get from calculation:
- *     capacity = fsCapacity - reserved
- *     other = fsUsed - used
- *
- * The avail is the result we want from calculation.
- * So, it could be:
- * A) avail = capacity - used
- * B) avail = fsAvail - Max(reserved - other, 0);
- *
- * To be Conservative, we could get min
- *     avail = Max(Min(A, B), 0);
- *
- * If we have a dedicated disk for hdds and are not using the reserved space,
- * then we should use DedicatedDiskSpaceUsage for
- * `hdds.datanode.du.factory.classname`,
- * Then it is much simpler, since we don't care about other usage:
- * {@code
- *  |----used----|             (avail)/fsAvail              |
- *  |<-              capacity/fsCapacity                  ->|
- * }
- *
- *  We have avail == fsAvail.
- *  </pre>
- */
-public final class VolumeInfo {
-
-  private static final Logger LOG = LoggerFactory.getLogger(VolumeInfo.class);
-
-  // Space usage calculator
-  private final VolumeUsage usage;
-
-  /**
-   * Builder for VolumeInfo.
-   */
-  public static class Builder {
-    private final ConfigurationSource conf;
-    private final String rootDir;
-    private SpaceUsageCheckFactory usageCheckFactory;
-
-    public Builder(String root, ConfigurationSource config) {
-      this.rootDir = root;
-      this.conf = config;
-    }
-
-    public Builder usageCheckFactory(SpaceUsageCheckFactory factory) {
-      this.usageCheckFactory = factory;
-      return this;
-    }
-
-    public VolumeInfo build() throws IOException {
-      return new VolumeInfo(this);
-    }
-  }
-
-  private VolumeInfo(Builder b) throws IOException {
-
-    File root = new File(b.rootDir);
-
-    boolean succeeded = root.isDirectory() || root.mkdirs();
-
-    if (!succeeded) {
-      LOG.error("Unable to create the volume root dir at : {}", root);
-      throw new IOException("Unable to create the volume root dir at " + root);
-    }
-
-    SpaceUsageCheckFactory usageCheckFactory = b.usageCheckFactory;
-    if (usageCheckFactory == null) {
-      usageCheckFactory = SpaceUsageCheckFactory.create(b.conf);
-    }
-    SpaceUsageCheckParams checkParams =
-        usageCheckFactory.paramsFor(root);
-
-    usage = new VolumeUsage(checkParams, b.conf);
-  }
-
-  public SpaceUsageSource getCurrentUsage() {
-    return usage.getCurrentUsage();
-  }
-
-  public void incrementUsedSpace(long usedSpace) {
-    usage.incrementUsedSpace(usedSpace);
-  }
-
-  public void decrementUsedSpace(long reclaimedSpace) {
-    usage.decrementUsedSpace(reclaimedSpace);
-  }
-
-  public void refreshNow() {
-    usage.refreshNow();
-  }
-
-  void shutdownUsageThread() {
-    usage.shutdown();
-  }
-
-  /**
-   * Only for testing. Do not use otherwise.
-   */
-  @VisibleForTesting
-  public VolumeUsage getUsageForTesting() {
-    return usage;
-  }
-
-  public long getReservedInBytes() {
-    return usage.getReservedBytes();
-  }
-}
diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeUsage.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeUsage.java
index 6c4f7bf35cbe..0fcab327a4d7 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeUsage.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeUsage.java
@@ -36,8 +36,61 @@
 import org.slf4j.LoggerFactory;
 
 /**
- * Class that wraps the space df of the Datanode Volumes used by SCM
- * containers.
+ * Stores information about a disk/volume.
+ *
+ * Since we have a reserved space for each volume for other usage,
+ * let's clarify the space values a bit here:
+ * - used: hdds actual usage.
+ * - avail: remaining space for hdds usage.
+ * - reserved: total space for other usage.
+ * - capacity: total space for hdds usage.
+ * - other: space used by other service consuming the same volume.
+ * - fsAvail: reported remaining space from local fs.
+ * - fsUsed: reported total used space from local fs.
+ * - fsCapacity: reported total capacity from local fs.
+ * - minVolumeFreeSpace (mvfs) : determines the free space for closing
+     containers.This is like adding a few reserved bytes to reserved space.
+     Dn's will send close container action to SCM at this limit, and it is
+     configurable.
+
+ *
+ * <pre>
+ * {@code
+ * |----used----|   (avail)   |++mvfs++|++++reserved+++++++|
+ * |<-     capacity                  ->|
+ *              |     fsAvail      |-------other-----------|
+ * |<-                   fsCapacity                      ->|
+ * }</pre>
+ * <pre>
+ * What we could directly get from local fs:
+ *     fsCapacity, fsAvail, (fsUsed = fsCapacity - fsAvail)
+ * We could get from config:
+ *     reserved
+ * Get from cmd line:
+ *     used: from cmd 'du' (by default)
+ * Get from calculation:
+ *     capacity = fsCapacity - reserved
+ *     other = fsUsed - used
+ *
+ * The avail is the result we want from calculation.
+ * So, it could be:
+ * A) avail = capacity - used
+ * B) avail = fsAvail - Max(reserved - other, 0);
+ *
+ * To be Conservative, we could get min
+ *     avail = Max(Min(A, B), 0);
+ *
+ * If we have a dedicated disk for hdds and are not using the reserved space,
+ * then we should use DedicatedDiskSpaceUsage for
+ * `hdds.datanode.du.factory.classname`,
+ * Then it is much simpler, since we don't care about other usage:
+ * {@code
+ *  |----used----|             (avail)/fsAvail              |
+ *  |<-              capacity/fsCapacity                  ->|
+ * }
+ *
+ *  We have avail == fsAvail.
+ *  </pre>
  */
 public class VolumeUsage {
 
@@ -120,7 +173,7 @@ public void refreshNow() {
     source.refreshNow();
   }
 
-  public long getReservedBytes() {
+  public long getReservedInBytes() {
     return reservedInBytes;
   }
 
diff --git a/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestReservedVolumeSpace.java b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestReservedVolumeSpace.java
index bcc123520e02..b8690a784ef3 100644
--- a/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestReservedVolumeSpace.java
+++ b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestReservedVolumeSpace.java
@@ -69,11 +69,11 @@ public void testDefaultConfig() throws Exception {
     // Gets the total capacity reported by Ozone, which may be limited to less than the volume's real capacity by the
     // DU reserved configurations.
     long volumeCapacity = hddsVolume.getCurrentUsage().getCapacity();
-    VolumeUsage usage = hddsVolume.getVolumeInfo().get().getUsageForTesting();
+    VolumeUsage usage = hddsVolume.getVolumeInfo().get();
 
     // Gets the actual total capacity without accounting for DU reserved space configurations.
     long totalCapacity = usage.realUsage().getCapacity();
-    long reservedCapacity = usage.getReservedBytes();
+    long reservedCapacity = usage.getReservedInBytes();
 
     assertEquals(getExpectedDefaultReserved(hddsVolume), reservedCapacity);
     assertEquals(totalCapacity - reservedCapacity, volumeCapacity);
@@ -93,11 +93,11 @@ public void testVolumeCapacityAfterReserve() throws Exception {
         HDDS_DATANODE_DIR_DU_RESERVED_PERCENT_DEFAULT);
 
     long volumeCapacity = hddsVolume.getCurrentUsage().getCapacity();
-    VolumeUsage usage = hddsVolume.getVolumeInfo().get().getUsageForTesting();
+    VolumeUsage usage = hddsVolume.getVolumeInfo().get();
 
     //Gets the actual total capacity
     long totalCapacity = usage.realUsage().getCapacity();
-    long reservedCapacity = usage.getReservedBytes();
+    long reservedCapacity = usage.getReservedInBytes();
     long reservedCalculated = (long) Math.ceil(totalCapacity * percentage);
 
     assertEquals(reservedCalculated, reservedCapacity);
@@ -131,8 +131,8 @@ public void testFallbackToPercentConfig() throws Exception {
         temp.toString() + ":500B");
     HddsVolume hddsVolume = volumeBuilder.conf(conf).build();
 
-    VolumeUsage usage = hddsVolume.getVolumeInfo().get().getUsageForTesting();
-    long reservedFromVolume = usage.getReservedBytes();
+    VolumeUsage usage = hddsVolume.getVolumeInfo().get();
+    long reservedFromVolume = usage.getReservedInBytes();
     assertNotEquals(0, reservedFromVolume);
 
     long totalCapacity = usage.realUsage().getCapacity();
@@ -212,7 +212,7 @@ public void testMinFreeSpaceCalculator() throws Exception {
 
 
   private long getExpectedDefaultReserved(HddsVolume volume) {
-    long totalCapacity = volume.getVolumeInfo().get().getUsageForTesting().realUsage().getCapacity();
+    long totalCapacity = volume.getVolumeInfo().get().realUsage().getCapacity();
     return (long) Math.ceil(totalCapacity * HDDS_DATANODE_DIR_DU_RESERVED_PERCENT_DEFAULT);
   }
 }
diff --git a/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestVolumeSet.java b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestVolumeSet.java
index d3fc67d053e7..521a9335b825 100644
--- a/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestVolumeSet.java
+++ b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestVolumeSet.java
@@ -23,7 +23,6 @@
 import static org.assertj.core.api.Assumptions.assumeThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertFalse;
-import static org.junit.jupiter.api.Assertions.assertNotNull;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import java.io.File;
@@ -213,8 +212,7 @@ public void testShutdown() throws Exception {
 
     // Verify that volume usage can be queried during shutdown.
     for (StorageVolume volume : volumesList) {
-      assertNotNull(volume.getVolumeInfo().get()
-              .getUsageForTesting());
+      assertThat(volume.getVolumeInfo()).isPresent();
       volume.getCurrentUsage();
     }
   }
diff --git a/hadoop-ozone/mini-cluster/src/main/java/org/apache/hadoop/ozone/UniformDatanodesFactory.java b/hadoop-ozone/mini-cluster/src/main/java/org/apache/hadoop/ozone/UniformDatanodesFactory.java
index 1029860375dd..328e8a9692c7 100644
--- a/hadoop-ozone/mini-cluster/src/main/java/org/apache/hadoop/ozone/UniformDatanodesFactory.java
+++ b/hadoop-ozone/mini-cluster/src/main/java/org/apache/hadoop/ozone/UniformDatanodesFactory.java
@@ -159,7 +159,7 @@ public Builder setNumDataVolumes(int n) {
      * for each volume in each datanode.
      * @param reservedSpace String that contains the numeric size value and ends with a
      *   {@link org.apache.hadoop.hdds.conf.StorageUnit} suffix. For example, "50GB".
-     * @see org.apache.hadoop.ozone.container.common.volume.VolumeInfo
+     * @see org.apache.hadoop.ozone.container.common.volume.VolumeUsage
      */
     public Builder setReservedSpace(String reservedSpace) {
       this.reservedSpace = reservedSpace;

From 35fe5381b1cc036b62a393388c06c78264d64ac4 Mon Sep 17 00:00:00 2001
From: "Doroszlai, Attila" <adoroszlai@apache.org>
Date: Mon, 24 Mar 2025 10:58:38 +0100
Subject: [PATCH 4/5] rename getVolumeInfo

---
 .../common/volume/MutableVolumeSet.java          |  6 +++---
 .../container/common/volume/StorageVolume.java   |  2 +-
 .../common/volume/VolumeInfoMetrics.java         |  6 +++---
 .../common/impl/TestHddsDispatcher.java          |  4 ++--
 .../common/volume/TestReservedVolumeSpace.java   | 16 ++++++++--------
 .../container/common/volume/TestVolumeSet.java   |  2 +-
 .../hadoop/ozone/TestMiniOzoneCluster.java       |  2 +-
 7 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/MutableVolumeSet.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/MutableVolumeSet.java
index 29cc05fcee70..2b41c4872de2 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/MutableVolumeSet.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/MutableVolumeSet.java
@@ -464,7 +464,7 @@ public StorageLocationReport[] getStorageReport() {
       StorageVolume volume;
       for (Map.Entry<String, StorageVolume> entry : volumeMap.entrySet()) {
         volume = entry.getValue();
-        Optional<VolumeUsage> volumeInfo = volume.getVolumeInfo();
+        Optional<VolumeUsage> volumeUsage = volume.getVolumeUsage();
         long scmUsed = 0;
         long remaining = 0;
         long capacity = 0;
@@ -472,9 +472,9 @@ public StorageLocationReport[] getStorageReport() {
         long spare = 0;
         String rootDir = volume.getVolumeRootDir();
         failed = true;
-        if (volumeInfo.isPresent()) {
+        if (volumeUsage.isPresent()) {
           try {
-            SpaceUsageSource usage = volumeInfo.get().getCurrentUsage();
+            SpaceUsageSource usage = volumeUsage.get().getCurrentUsage();
             scmUsed = usage.getUsedSpace();
             remaining = usage.getAvailable();
             capacity = usage.getCapacity();
diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java
index 28c062e43252..318fa0ab9df0 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/StorageVolume.java
@@ -476,7 +476,7 @@ public void refreshVolumeUsage() {
   }
 
   /** @see #getCurrentUsage() */
-  public Optional<VolumeUsage> getVolumeInfo() {
+  public Optional<VolumeUsage> getVolumeUsage() {
     return volumeUsage;
   }
 
diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfoMetrics.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfoMetrics.java
index 7a9b465a68e9..c864f416cdb4 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfoMetrics.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/VolumeInfoMetrics.java
@@ -131,9 +131,9 @@ public long getContainers() {
   public void getMetrics(MetricsCollector collector, boolean all) {
     MetricsRecordBuilder builder = collector.addRecord(metricsSourceName);
     registry.snapshot(builder, all);
-    volume.getVolumeInfo().ifPresent(volumeInfo -> {
-      SpaceUsageSource usage = volumeInfo.getCurrentUsage();
-      long reserved = volumeInfo.getReservedInBytes();
+    volume.getVolumeUsage().ifPresent(volumeUsage -> {
+      SpaceUsageSource usage = volumeUsage.getCurrentUsage();
+      long reserved = volumeUsage.getReservedInBytes();
       builder
           .addGauge(CAPACITY, usage.getCapacity())
           .addGauge(AVAILABLE, usage.getAvailable())
diff --git a/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/impl/TestHddsDispatcher.java b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/impl/TestHddsDispatcher.java
index 1243b5d46b0b..152789751157 100644
--- a/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/impl/TestHddsDispatcher.java
+++ b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/impl/TestHddsDispatcher.java
@@ -289,8 +289,8 @@ public void testContainerCloseActionWhenVolumeFull(
       HddsDispatcher hddsDispatcher = new HddsDispatcher(
           conf, containerSet, volumeSet, handlers, context, metrics, null);
       hddsDispatcher.setClusterId(scmId.toString());
-      containerData.getVolume().getVolumeInfo()
-          .ifPresent(volumeInfo -> volumeInfo.incrementUsedSpace(50));
+      containerData.getVolume().getVolumeUsage()
+          .ifPresent(usage -> usage.incrementUsedSpace(50));
       usedSpace.addAndGet(50);
       ContainerCommandResponseProto response = hddsDispatcher
           .dispatch(getWriteChunkRequest(dd.getUuidString(), 1L, 1L), null);
diff --git a/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestReservedVolumeSpace.java b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestReservedVolumeSpace.java
index b8690a784ef3..55fc68f4f56b 100644
--- a/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestReservedVolumeSpace.java
+++ b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestReservedVolumeSpace.java
@@ -69,7 +69,7 @@ public void testDefaultConfig() throws Exception {
     // Gets the total capacity reported by Ozone, which may be limited to less than the volume's real capacity by the
     // DU reserved configurations.
     long volumeCapacity = hddsVolume.getCurrentUsage().getCapacity();
-    VolumeUsage usage = hddsVolume.getVolumeInfo().get();
+    VolumeUsage usage = hddsVolume.getVolumeUsage().get();
 
     // Gets the actual total capacity without accounting for DU reserved space configurations.
     long totalCapacity = usage.realUsage().getCapacity();
@@ -93,7 +93,7 @@ public void testVolumeCapacityAfterReserve() throws Exception {
         HDDS_DATANODE_DIR_DU_RESERVED_PERCENT_DEFAULT);
 
     long volumeCapacity = hddsVolume.getCurrentUsage().getCapacity();
-    VolumeUsage usage = hddsVolume.getVolumeInfo().get();
+    VolumeUsage usage = hddsVolume.getVolumeUsage().get();
 
     //Gets the actual total capacity
     long totalCapacity = usage.realUsage().getCapacity();
@@ -117,7 +117,7 @@ public void testReservedWhenBothConfigSet() throws Exception {
         folder.toString() + ":500B");
     HddsVolume hddsVolume = volumeBuilder.conf(conf).build();
 
-    long reservedFromVolume = hddsVolume.getVolumeInfo().get()
+    long reservedFromVolume = hddsVolume.getVolumeUsage().get()
             .getReservedInBytes();
     assertEquals(500, reservedFromVolume);
   }
@@ -131,7 +131,7 @@ public void testFallbackToPercentConfig() throws Exception {
         temp.toString() + ":500B");
     HddsVolume hddsVolume = volumeBuilder.conf(conf).build();
 
-    VolumeUsage usage = hddsVolume.getVolumeInfo().get();
+    VolumeUsage usage = hddsVolume.getVolumeUsage().get();
     long reservedFromVolume = usage.getReservedInBytes();
     assertNotEquals(0, reservedFromVolume);
 
@@ -151,7 +151,7 @@ public void testInvalidConfig() throws Exception {
         folder.toString() + ":500C");
     HddsVolume hddsVolume1 = volumeBuilder.conf(conf1).build();
 
-    long reservedFromVolume1 = hddsVolume1.getVolumeInfo().get()
+    long reservedFromVolume1 = hddsVolume1.getVolumeUsage().get()
             .getReservedInBytes();
     assertEquals(getExpectedDefaultReserved(hddsVolume1), reservedFromVolume1);
 
@@ -161,7 +161,7 @@ public void testInvalidConfig() throws Exception {
     conf2.set(HDDS_DATANODE_DIR_DU_RESERVED_PERCENT, "20");
     HddsVolume hddsVolume2 = volumeBuilder.conf(conf2).build();
 
-    long reservedFromVolume2 = hddsVolume2.getVolumeInfo().get()
+    long reservedFromVolume2 = hddsVolume2.getVolumeUsage().get()
             .getReservedInBytes();
     assertEquals(getExpectedDefaultReserved(hddsVolume2), reservedFromVolume2);
   }
@@ -188,7 +188,7 @@ public void testPathsCanonicalized() throws Exception {
     conf.set(ScmConfigKeys.HDDS_DATANODE_DIR_DU_RESERVED, symlink + ":500B");
     HddsVolume hddsVolume = volumeBuilder.conf(conf).build();
 
-    long reservedFromVolume = hddsVolume.getVolumeInfo().get().getReservedInBytes();
+    long reservedFromVolume = hddsVolume.getVolumeUsage().get().getReservedInBytes();
     assertEquals(500, reservedFromVolume);
   }
 
@@ -212,7 +212,7 @@ public void testMinFreeSpaceCalculator() throws Exception {
 
 
   private long getExpectedDefaultReserved(HddsVolume volume) {
-    long totalCapacity = volume.getVolumeInfo().get().realUsage().getCapacity();
+    long totalCapacity = volume.getVolumeUsage().get().realUsage().getCapacity();
     return (long) Math.ceil(totalCapacity * HDDS_DATANODE_DIR_DU_RESERVED_PERCENT_DEFAULT);
   }
 }
diff --git a/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestVolumeSet.java b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestVolumeSet.java
index 521a9335b825..2f27b5363f4b 100644
--- a/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestVolumeSet.java
+++ b/hadoop-hdds/container-service/src/test/java/org/apache/hadoop/ozone/container/common/volume/TestVolumeSet.java
@@ -212,7 +212,7 @@ public void testShutdown() throws Exception {
 
     // Verify that volume usage can be queried during shutdown.
     for (StorageVolume volume : volumesList) {
-      assertThat(volume.getVolumeInfo()).isPresent();
+      assertThat(volume.getVolumeUsage()).isPresent();
       volume.getCurrentUsage();
     }
   }
diff --git a/hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/TestMiniOzoneCluster.java b/hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/TestMiniOzoneCluster.java
index 1ab32f738458..6e26a3ae7ac6 100644
--- a/hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/TestMiniOzoneCluster.java
+++ b/hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/TestMiniOzoneCluster.java
@@ -279,7 +279,7 @@ public void testMultipleDataDirs() throws Exception {
 
     volumeList.forEach(storageVolume -> assertEquals(
             (long) StorageSize.parse(reservedSpace).getValue(),
-            storageVolume.getVolumeInfo().get().getReservedInBytes()));
+            storageVolume.getVolumeUsage().get().getReservedInBytes()));
   }
 
 }

From 872eb18e4be61e2a7f809473b5513f17fa4ccaa2 Mon Sep 17 00:00:00 2001
From: "Doroszlai, Attila" <adoroszlai@apache.org>
Date: Mon, 24 Mar 2025 11:46:23 +0100
Subject: [PATCH 5/5] fix javadoc

---
 .../apache/hadoop/ozone/container/common/volume/HddsVolume.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/HddsVolume.java b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/HddsVolume.java
index d355908e5e91..b88961e04ae4 100644
--- a/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/HddsVolume.java
+++ b/hadoop-hdds/container-service/src/main/java/org/apache/hadoop/ozone/container/common/volume/HddsVolume.java
@@ -49,7 +49,7 @@
 /**
  * HddsVolume represents volume in a datanode. {@link MutableVolumeSet}
  * maintains a list of HddsVolumes, one for each volume in the Datanode.
- * {@link VolumeInfo} in encompassed by this class.
+ * {@link VolumeUsage} in encompassed by this class.
  * <p>
  * The disk layout per volume is as follows:
  * <p>../hdds/VERSION