man: document that link-ed files must be on /

Fixes #8307.

diff --git a/man/systemctl.xml b/man/systemctl.xml
index c311548f4b02bf68ab9f043ebd0f2229b212cac6..1588ca719da17c9819020f2db8a85b8ffa99eadb 100644 (file)
--- a/man/systemctl.xml
+++ b/man/systemctl.xml
@@ -1120,7 +1120,10 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
             automatically searched for unit files with appropriate names), or absolute paths to unit files (in which
             case these files are read directly). If a specified unit file is located outside of the usual unit file
             directories, an additional symlink is created, linking it into the unit configuration path, thus ensuring
             automatically searched for unit files with appropriate names), or absolute paths to unit files (in which
             case these files are read directly). If a specified unit file is located outside of the usual unit file
             directories, an additional symlink is created, linking it into the unit configuration path, thus ensuring

-            it is found when requested by commands such as <command>start</command>.</para>
+            it is found when requested by commands such as <command>start</command>. The file system where the linked
+            unit files are located must be accessible when systemd is started (e.g. anything underneath
+            <filename>/home</filename> or <filename>/var</filename> is not allowed, unless those directories are
+            located on the root file system).</para>

 
             <para>This command will print the file system operations executed. This output may be suppressed by passing
             <option>--quiet</option>.
 
             <para>This command will print the file system operations executed. This output may be suppressed by passing
             <option>--quiet</option>.


@@ -1350,7 +1353,10 @@ Jan 12 10:46:45 example.com bluetoothd[8900]: gatt-time-server: Input/output err
             <para>Link a unit file that is not in the unit file search paths into the unit file search path. This
             command expects an absolute path to a unit file. The effect of this may be undone with
             <command>disable</command>. The effect of this command is that a unit file is made available for commands
             <para>Link a unit file that is not in the unit file search paths into the unit file search path. This
             command expects an absolute path to a unit file. The effect of this may be undone with
             <command>disable</command>. The effect of this command is that a unit file is made available for commands

-            such as <command>start</command>, even though it is not installed directly in the unit search path.</para>
+            such as <command>start</command>, even though it is not installed directly in the unit search path. The
+            file system where the linked unit files are located must be accessible when systemd is started
+            (e.g. anything underneath <filename>/home</filename> or <filename>/var</filename> is not allowed, unless
+            those directories are located on the root file system).</para>

           </listitem>
         </varlistentry>
 
           </listitem>
         </varlistentry>