HDFS-17455. Modify patch based on comments

hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java

@@ -520,15 +520,20 @@ private LocatedBlock fetchBlockAt(long offset, long length, boolean useCache)
         // Update the LastLocatedBlock, if offset is for last block.
         if (offset >= locatedBlocks.getFileLength()) {
           setLocatedBlocksFields(newBlocks, getLastBlockLength(newBlocks));
+          // Here locatedBlocks has been updated, need to check offset again.
+          // If offset to the portion of the last block, will return the last block,
+          // otherwise the block containing the specified offset needs to be searched again.
+          if (offset >= locatedBlocks.getFileLength()) {
+            return locatedBlocks.getLastLocatedBlock();
+          } else {
+            targetBlockIdx = locatedBlocks.findBlock(offset);
+            assert targetBlockIdx >= 0 && targetBlockIdx < locatedBlocks.locatedBlockCount();
+          }
         } else {
           locatedBlocks.insertRange(targetBlockIdx,
               newBlocks.getLocatedBlocks());
         }
       }
-      if (targetBlockIdx >= locatedBlocks.locatedBlockCount()) {
-        DFSClient.LOG.debug("Could not find target position " + offset);
-        throw new EOFException("Could not find target position " + offset);
-      }
       return locatedBlocks.get(targetBlockIdx);
     }
   }

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSInputStream.java

@@ -305,8 +305,6 @@ public void testReadWithoutPreferredCachingReplica() throws IOException {
   public void testCreateBlockReaderWhenInvalidBlockTokenException() throws
       IOException, InterruptedException, TimeoutException {
     GenericTestUtils.setLogLevel(DFSClient.LOG, Level.DEBUG);
-    GenericTestUtils.LogCapturer logs =
-        GenericTestUtils.LogCapturer.captureLogs(DFSClient.LOG);
     Configuration conf = new Configuration();
     DFSClientFaultInjector oldFaultInjector = DFSClientFaultInjector.get();
     try (MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).numDataNodes(3).build()) {
@@ -363,9 +361,6 @@ public Void answer(InvocationOnMock invocation) throws Throwable {
         int read = in.read(buf, 0, bufLen);
         assertEquals(1024, read);
       }
-
-      assertTrue(logs.getOutput().contains("Could not find target position 1"));
-      logs.clearOutput();
     } finally {
       DFSClientFaultInjector.set(oldFaultInjector);
     }