HADOOP-14072. AliyunOSS: Failed to read from stream when seek beyond the download size. Contributed by Genmao Yu

hadoop-tools/hadoop-aliyun/src/main/java/org/apache/hadoop/fs/aliyun/oss/AliyunOSSInputStream.java

@@ -224,8 +224,10 @@ public class AliyunOSSInputStream extends FSInputStream {
     if (position == pos) {
       return;
     } else if (pos > position && pos < position + partRemaining) {
-      AliyunOSSUtils.skipFully(wrappedStream, pos - position);
+      long len = pos - position;
+      AliyunOSSUtils.skipFully(wrappedStream, len);
       position = pos;
+      partRemaining -= len;
     } else {
       reopen(pos);
     }

hadoop-tools/hadoop-aliyun/src/test/java/org/apache/hadoop/fs/aliyun/oss/contract/TestAliyunOSSContractSeek.java

@@ -19,8 +19,15 @@
 package org.apache.hadoop.fs.aliyun.oss.contract;
 
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FSDataInputStream;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.fs.contract.AbstractContractSeekTest;
 import org.apache.hadoop.fs.contract.AbstractFSContract;
+import org.junit.Test;
+
+import static org.apache.hadoop.fs.contract.ContractTestUtils.createFile;
+import static org.apache.hadoop.fs.contract.ContractTestUtils.dataset;
 
 /**
  * Aliyun OSS contract seeking tests.
@@ -31,4 +38,23 @@ public class TestAliyunOSSContractSeek extends AbstractContractSeekTest {
   protected AbstractFSContract createContract(Configuration conf) {
     return new AliyunOSSContract(conf);
   }
+
+  @Test
+  public void testSeekBeyondDownloadSize() throws Throwable {
+    describe("seek and read beyond download size.");
+
+    Path byteFile = path("byte_file.txt");
+    // 'fs.oss.multipart.download.size' = 100 * 1024
+    byte[] block = dataset(100 * 1024 + 10, 0, 255);
+    FileSystem fs = getFileSystem();
+    createFile(fs, byteFile, true, block);
+
+    FSDataInputStream instream = getFileSystem().open(byteFile);
+    instream.seek(100 * 1024 - 1);
+    assertEquals(100 * 1024 - 1, instream.getPos());
+    assertEquals(144, instream.read());
+    instream.seek(100 * 1024 + 1);
+    assertEquals(100 * 1024 + 1, instream.getPos());
+    assertEquals(146, instream.read());
+  }
 }