diff --git a/include/linux/fs.h b/include/linux/fs.h
index 661c7c5..853a02f 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -623,6 +623,9 @@
 	I_MUTEX_QUOTA
 };
 
+extern void inode_double_lock(struct inode *inode1, struct inode *inode2);
+extern void inode_double_unlock(struct inode *inode1, struct inode *inode2);
+
 /*
  * NOTE: in a 32bit arch with a preemptable kernel and
  * an UP compile the i_size_read/write must be atomic