HADOOP-19052.Hadoop use Shell command to get the count of the hard link which takes a lot of time

Author: liangyu-1

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

@@ -209,6 +209,15 @@ public static void createHardLinkMult(File parentDir, String[] fileBaseNames,
                  parentDir.toPath().resolve(name));
     }
   }
+  @VisibleForTesting
+  static boolean supportsHardLink(File f) {
+    try {
+      FileStore store = Files.getFileStore(f.toPath());
+      return store.supportsFileAttributeView(FileAttributeView);
+    } catch (IOException e) {
+      return false;
+    }
+  }
 
    /**
    * Retrieves the number of links to the specified file.
@@ -226,7 +235,7 @@ public static int getLinkCount(File fileName) throws IOException {
       throw new FileNotFoundException(fileName + " not found.");
     }
 
-    if (Files.getFileStore(fileName.toPath()).supportsFileAttributeView(FileAttributeView)) {
+    if (supportsHardLink(fileName)) {
       return (int) Files.getAttribute(fileName.toPath(), FileAttribute);
     }
 

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

@@ -207,14 +207,7 @@ private String fetchFileContents(File file)
     return new String(result);
   }
 
-  private boolean supportsHardLink(File f) {
-    try {
-      FileStore store = Files.getFileStore(f.toPath());
-      return store.supportsFileAttributeView("unix");
-    } catch (IOException e) {
-      return false;
-    }
-  }
+
 
   /**
    * Sanity check the simplest case of HardLink.getLinkCount()