man: mention /proc/self/mountinfo in systemd.mount(5)

[elogind.git] / man / systemd.mount.xml

diff --git a/man/systemd.mount.xml b/man/systemd.mount.xml
index 219ef6531e2e7f87b650d1c22ee8959c113bc2ef..f319cf7ce9d36f8921f23e724ced28efc9437764 100644 (file)
--- a/man/systemd.mount.xml
+++ b/man/systemd.mount.xml
@@ -75,7 +75,14 @@
                 binary is executed in, and in
                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
                 which define the way the processes are
-                terminated.</para>
+                terminated. Note that the User= and Group= options are
+                not particularly useful for mount units specifying a
+                <literal>Type=</literal> option or using configuration
+                not specified in <filename>/etc/fstab</filename>;
+                <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+                will refuse options that aren't listed in
+                <filename>/etc/fstab</filename> if it is not run as
+                UID 0.</para>
 
                 <para>Mount units must be named after the mount point
                 directories they control. Example: the mount point
@@ -95,10 +102,21 @@
                 in the file system hierarchy, a dependency between both
                 units is created automatically.</para>
 
-                <para>Mount points created at runtime independent on
-                unit files or <filename>/etc/fstab</filename> will be
+                <para>Mount points created at runtime (independently of
+                unit files or <filename>/etc/fstab</filename>) will be
                 monitored by systemd and appear like any other mount
-                unit in systemd.</para>
+                unit in systemd.
+                See <filename>/proc/self/mountinfo</filename> description
+                in <citerefentry><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+                </para>
+
+                <para>Some file systems have special semantics as API
+                file systems for kernel-to-userspace and
+                userspace-to-userpace interfaces. Some of them may not
+                be changed via mount units, and cannot be disabled.
+                For a longer discussion see <ulink
+                url="http://www.freedesktop.org/wiki/Software/systemd/APIFileSystems">API
+                File Systems</ulink>.</para>
         </refsect1>
 
         <refsect1>
@@ -138,8 +156,16 @@
                 <literal>h</literal>, <literal>ms</literal>.</para>
 
                 <para>If a mount point is configured in both
-                <filename>/etc/fstab</filename> and a unit file, the
-                configuration in the latter takes precedence.</para>
+                <filename>/etc/fstab</filename> and a unit file that
+                is stored below <filename>/usr</filename> the former
+                will take precedence. If the unit file is stored below
+                <filename>/etc</filename> it will take
+                precedence. This means: native unit files take
+                precedence over traditional configuration files, but
+                this is superseded by the rule that configuration in
+                <filename>/etc</filename> will always take precedence
+                over configuration in
+                <filename>/usr</filename>.</para>
         </refsect1>
 
         <refsect1>
@@ -274,8 +300,10 @@
                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
-                          <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+                          <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
                   </para>
         </refsect1>