HADOOP-19387: Fix LocalDirAllocator::getLocalPathForWrite unable to recover when the thread is interrupted

Author: nirro01

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/LocalDirAllocator.java

@@ -346,9 +346,9 @@ private Context confChanged(Configuration conf)
         }
         ctx.localDirs = dirs.toArray(new Path[dirs.size()]);
         ctx.dirDF = dfList.toArray(new DF[dirs.size()]);
-        ctx.savedLocalDirs = newLocalDirs;
 
         if (dirs.size() > 0) {
+          ctx.savedLocalDirs = newLocalDirs;
           // randomize the first disk picked in the round-robin selection
           ctx.dirNumLastAccessed.set(dirIndexRandomizer.nextInt(dirs.size()));
         }

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestLocalDirAllocator.java

@@ -567,5 +567,23 @@ public void testDirectoryRecovery() throws Throwable {
     // and expect to get a new file back
     dirAllocator.getLocalPathForWrite("file2", -1, conf);
   }
+
+  /**
+   * Test for HADOOP-19387 LocalDirAllocator cannot recover after thread interruption.
+   */
+  @Test(timeout = 30000)
+  public void testInterruptionRecovery() throws Throwable {
+
+    String dir0 = buildBufferDir(ROOT, 7);
+    conf.set(CONTEXT, dir0);
+    try {
+      Thread.currentThread().interrupt();
+      assertThrows(DiskErrorException.class, () -> dirAllocator.getLocalPathForWrite("file2", 1, conf));
+    } finally {
+      Thread.interrupted();
+    }
+    // expect to get a file with no exceptions
+    dirAllocator.getLocalPathForWrite("file2", 1, conf);
+  }
 }