diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst
index 099d45ac8d8f703121a2c95e8e0b7cf048c6ecac..535021c46260799ff214c04c014a5903dc3cdfb4 100644
--- a/Documentation/filesystems/f2fs.rst
+++ b/Documentation/filesystems/f2fs.rst
@@ -258,6 +258,8 @@ compress_extension=%s  Support adding specified extension, so that f2fs can enab
                        on compression extension list and enable compression on
                        these file by default rather than to enable it via ioctl.
                        For other files, we can still enable compression via ioctl.
+                       Note that, there is one reserved special extension '*', it
+                       can be set to enable compression for all files.
 ====================== ============================================================
 
 Debugfs Entries