man: document automatic dependencies

For all units ensure there's an "Automatic Dependencies" section in the
man page, and explain which dependencies are automatically added in all
cases, and which ones are added on top if DefaultDependencies=yes is
set.

This is also done for systemd.exec(5), systemd.resource-control(5) and
systemd.unit(5) as these pages describe common behaviour of various unit
types.

1 files changed, 17 insertions, 3 deletions

diff --git a/man/systemd.automount.xml b/man/systemd.automount.xml
index 26a0f291dd..1b0ae832da 100644
--- a/man/systemd.automount.xml
+++ b/man/systemd.automount.xml
@@ -85,10 +85,24 @@
 
     <para>Automount units may be used to implement on-demand mounting
     as well as parallelized mounting of file systems.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>If an automount unit is beneath another mount unit in the
+    file system hierarchy, both a requirement and an ordering
+    dependency between both units are created automatically.</para>
+
+    <para>An implicit <varname>Before=</varname> dependency is created
+    between an automount unit and the mount unit it activates.</para>
+
+    <para>Automount units acquire automatic <varname>Before=</varname>
+    and <varname>Conflicts=</varname> on
+    <filename>umount.target</filename> in order to be stopped during
+    shutdown, unless <varname>DefaultDependencies=no</varname> is
+    set.</para>
 
-    <para>If an automount point is beneath another mount point in the
-    file system hierarchy, a dependency between both units is created
-    automatically.</para>
   </refsect1>
 
   <refsect1>