HDDS-14161. getBlockLocations returns null for zero-byte files (#9491)

Author: stuxuhai

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/fs/ozone/AbstractOzoneFileSystemTest.java

@@ -2143,6 +2143,15 @@ public void testOzoneManagerListLocatedStatusAndListStatus() throws IOException
     assertFalse(fileStatuses[0] instanceof LocatedFileStatus);
   }
 
+  @Test
+  public void testOzoneManagerListLocatedStatusForZeroByteFile() throws IOException {
+    String directory = RandomStringUtils.secure().nextAlphanumeric(5);
+    String filePath = RandomStringUtils.secure().nextAlphanumeric(5);
+    Path path = createPath("/" + directory + "/" + filePath);
+
+    OzoneFileSystemTests.listLocatedStatusForZeroByteFile(fs, path);
+  }
+
   @Test
   void testOzoneManagerFileSystemInterface() throws IOException {
     String dirPath = RandomStringUtils.secure().nextAlphanumeric(5);

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/fs/ozone/AbstractRootedOzoneFileSystemTest.java

@@ -404,6 +404,19 @@ void testDeleteCreatesFakeParentDir() throws Exception {
     assertTrue(fs.delete(grandparent, true));
   }
 
+  @Test
+  void testListLocatedStatusForZeroByteFile() throws Exception {
+    Path parent = new Path(bucketPath, "testListLocatedStatusForZeroByteFile");
+    Path path = new Path(parent, "key1");
+
+    try {
+      OzoneFileSystemTests.listLocatedStatusForZeroByteFile(fs, path);
+    } finally {
+      // Cleanup
+      fs.delete(parent, true);
+    }
+  }
+
   @Test
   void testListStatus() throws Exception {
     Path parent = new Path(bucketPath, "testListStatus");

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/fs/ozone/OzoneFileSystemTests.java

@@ -24,14 +24,18 @@
 import static org.apache.hadoop.ozone.OzoneConsts.OZONE_URI_SCHEME;
 import static org.assertj.core.api.Assertions.assertThat;
 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 java.io.IOException;
 import java.net.URI;
 import java.util.Objects;
 import java.util.Set;
 import java.util.TreeSet;
+import org.apache.hadoop.fs.BlockLocation;
 import org.apache.hadoop.fs.FileStatus;
 import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.LocatedFileStatus;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.RemoteIterator;
 import org.apache.hadoop.fs.contract.ContractTestUtils;
@@ -125,4 +129,37 @@ static void createKeyWithECReplicationConfiguration(OzoneConfiguration inputConf
       ContractTestUtils.touch(fileSystem, keyPath);
     }
   }
+
+  public static void listLocatedStatusForZeroByteFile(FileSystem fs, Path path) throws IOException {
+    // create empty file
+    ContractTestUtils.touch(fs, path);
+
+    RemoteIterator<LocatedFileStatus> listLocatedStatus = fs.listLocatedStatus(path);
+    int count = 0;
+
+    while (listLocatedStatus.hasNext()) {
+      LocatedFileStatus locatedFileStatus = listLocatedStatus.next();
+      assertEquals(0, locatedFileStatus.getLen());
+      BlockLocation[] blockLocations = locatedFileStatus.getBlockLocations();
+      assertNotNull(blockLocations);
+      assertEquals(0, blockLocations.length);
+
+      count++;
+    }
+    assertEquals(1, count);
+
+    count = 0;
+    RemoteIterator<FileStatus> listStatus = fs.listStatusIterator(path);
+    while (listStatus.hasNext()) {
+      FileStatus fileStatus = listStatus.next();
+      assertEquals(0, fileStatus.getLen());
+      assertFalse(fileStatus instanceof LocatedFileStatus);
+      count++;
+    }
+    assertEquals(1, count);
+
+    FileStatus[] fileStatuses = fs.listStatus(path.getParent());
+    assertEquals(1, fileStatuses.length);
+    assertFalse(fileStatuses[0] instanceof LocatedFileStatus);
+  }
 }

hadoop-ozone/ozonefs-common/src/main/java/org/apache/hadoop/fs/ozone/BasicOzoneFileSystem.java

@@ -954,7 +954,8 @@ public RemoteIterator<LocatedFileStatus> listLocatedStatus(Path f)
       throws IOException {
     incrementCounter(Statistic.INVOCATION_LIST_LOCATED_STATUS);
     return new OzoneFileStatusIterator<>(f,
-        (stat) -> stat instanceof LocatedFileStatus ? (LocatedFileStatus) stat : new LocatedFileStatus(stat, null),
+        (stat) -> stat instanceof LocatedFileStatus ? (LocatedFileStatus) stat :
+            new LocatedFileStatus(stat, stat.isFile() ? new BlockLocation[0] : null),
         false);
   }
 

hadoop-ozone/ozonefs-common/src/main/java/org/apache/hadoop/fs/ozone/BasicRootedOzoneFileSystem.java

@@ -1184,7 +1184,8 @@ public RemoteIterator<LocatedFileStatus> listLocatedStatus(Path f)
       throws IOException {
     incrementCounter(Statistic.INVOCATION_LIST_LOCATED_STATUS);
     return new OzoneFileStatusIterator<>(f,
-        (stat) -> stat instanceof LocatedFileStatus ? (LocatedFileStatus) stat : new LocatedFileStatus(stat, null),
+        (stat) -> stat instanceof LocatedFileStatus ? (LocatedFileStatus) stat :
+            new LocatedFileStatus(stat, stat.isFile() ? new BlockLocation[0] : null),
         false);
   }