Ocfs2/move_extents: move/defrag extents within a certain range.

the basic logic of moving extents for a file is pretty like punching-hole
sequence, walk the extents within the range as user specified, calculating
an appropriate len to defrag/move, then let ocfs2_defrag/move_extent() to
do the actual moving.

This func ends up setting 'OCFS2_MOVE_EXT_FL_COMPLETE' to userpace if operation
gets done successfully.

Signed-off-by: Tristan Ye <tristan.ye@oracle.com>
diff --git a/fs/ocfs2/move_extents.h b/fs/ocfs2/move_extents.h
index 27570f7..4e143e8 100644
--- a/fs/ocfs2/move_extents.h
+++ b/fs/ocfs2/move_extents.h
@@ -17,4 +17,6 @@
 #ifndef OCFS2_MOVE_EXTENTS_H
 #define OCFS2_MOVE_EXTENTS_H
 
+int ocfs2_ioctl_move_extents(struct file *filp,  void __user *argp);
+
 #endif /* OCFS2_MOVE_EXTENTS_H */