lib/oe: copyhardlinktree - detect mount points

index 1310e38..f1905c3 100644
@@ -90,7 +90,7 @@ def copyhardlinktree(src, dst):
     if os.path.isdir(src) and not len(os.listdir(src)):
         return
 
-    if (os.stat(src).st_dev ==  os.stat(dst).st_dev):
+    if (getmount(src) ==  getmount(dst)):
         # Need to copy directories only with tar first since cp will error if tw
         # writers try and create a directory at the same time
         cmd = 'cd %s; find . -type d -print | tar -cf - -C %s -p --files-from -

@@ -259,3 +259,12 @@ def realpath(file, root, use_physdir = True, loop_cnt = 100,
         raise
 
     return file
+
+def getmount(path):
+    """ Returns the mount point of the path, using realpath """
+    path = realpath(path)
+    while path != os.path.sep:
+        if os.path.ismount(path):
+            return path
+        path = os.path.abspath(os.path.join(path, os.pardir))
+    return path