diff -up util-linux-2.23.2/sys-utils/mount.8.kzak util-linux-2.23.2/sys-utils/mount.8
--- util-linux-2.23.2/sys-utils/mount.8.kzak	2015-06-24 10:44:54.888929869 +0200
+++ util-linux-2.23.2/sys-utils/mount.8	2015-06-24 10:48:10.022436703 +0200
@@ -865,9 +865,10 @@ Some of these options are only useful wh
 .I /etc/fstab
 file.
 
-Some of these options could be enabled or disabled by default
-in the system kernel. To check the current setting see the options
-in /proc/mounts.
+Some of these  options  could be enabled or disabled by default in the system
+kernel.  To check the current setting see the options in /proc/mounts.  Note
+that filesystems also have per-filesystem specific default mount options (see
+for example tune2fs -l output for extN filesystems).
 
 The following options apply to any filesystem that is being
 mounted (but not every filesystem actually honors them - e.g., the
@@ -973,6 +974,9 @@ For more details, see
 .B defaults
 Use default options:
 .BR rw ", " suid ", " dev ", " exec ", " auto ", " nouser ", and " async.
+
+Note that the real set of the all default mount options depends on kernel
+and filesystem type. See the begin of this section for more details.
 .TP
 .B dev
 Interpret character or block special devices on the filesystem.