From f3d1af870512c96006aee43de4a99f3475a215f5 Mon Sep 17 00:00:00 2001
From: maobaolong <307499405@qq.com>
Date: Mon, 24 Jul 2023 12:38:37 +0800
Subject: [PATCH] Support getFileBlockLocation in LocalCacheFileSystem

### What changes are proposed in this pull request?

Delegate `getFileBlockLocation` to external file system in `LocalCacheFileSystem`.

### Why are the changes needed?

Otherwise, `LocalCacheFileSystem` inherits the default behavior of `org.apache.hadoop.fs.FileSystem` which returns `localhost` only.

### Does this PR introduce any user facing changes?

No.

			pr-link: Alluxio/alluxio#17672
			change-id: cid-eb545dbd8ed42001d074fecfb9c8d6b118a559c1
---
 .../alluxio/hadoop/LocalCacheFileSystem.java  | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/core/client/hdfs/src/main/java/alluxio/hadoop/LocalCacheFileSystem.java b/core/client/hdfs/src/main/java/alluxio/hadoop/LocalCacheFileSystem.java
index 88e6002a5ffa..5b0c74fd6fe7 100644
--- a/core/client/hdfs/src/main/java/alluxio/hadoop/LocalCacheFileSystem.java
+++ b/core/client/hdfs/src/main/java/alluxio/hadoop/LocalCacheFileSystem.java
@@ -27,6 +27,7 @@
 import alluxio.wire.FileInfo;
 
 import com.google.common.base.Preconditions;
+import org.apache.hadoop.fs.BlockLocation;
 import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileStatus;
@@ -213,4 +214,22 @@ public boolean mkdirs(Path f, FsPermission permission) throws IOException {
   public FileStatus getFileStatus(Path f) throws IOException {
     return mExternalFileSystem.getFileStatus(f);
   }
+
+  @Override
+  public BlockLocation[] getFileBlockLocations(FileStatus file, long start,
+      long len) throws IOException {
+    // Applications use the block information here to schedule/distribute the tasks.
+    // Return the UFS locations directly instead of the local cache location,
+    // so the application can schedule the tasks accordingly
+    return mExternalFileSystem.getFileBlockLocations(file, start, len);
+  }
+
+  @Override
+  public BlockLocation[] getFileBlockLocations(Path p, long start, long len)
+      throws IOException {
+    // Applications use the block information here to schedule/distribute the tasks.
+    // Return the UFS locations directly instead of the local cache location,
+    // so the application can schedule the tasks accordingly
+    return mExternalFileSystem.getFileBlockLocations(p, start, len);
+  }
 }