diff --git a/Documentation/filesystems/9p.rst b/Documentation/filesystems/9p.rst
index f054d1c45e86..671fef39a802 100644
--- a/Documentation/filesystems/9p.rst
+++ b/Documentation/filesystems/9p.rst
@@ -158,6 +158,16 @@ Options
 		/sys/fs/9p/caches. (applies only to cache=fscache)
   ============= ===============================================================
 
+Behavior
+========
+
+This section aims at describing 9p 'quirks' that can be different
+from a local filesystem behaviors.
+
+ - Setting O_NONBLOCK on a file will make client reads return as early
+   as the server returns some data instead of trying to fill the read
+   buffer with the requested amount of bytes or end of file is reached.
+
 Resources
 =========