chiark / gitweb /
bus: send status message from proxyd to systemd about client we are working for
[elogind.git] / man / systemd-halt.service.xml
index 812281e60d5e0cb2e006b70bfe13b680fecc1c7e..0737d058d1533085426d97644b7d1bfb07bf08bc 100644 (file)
                 <filename>kexec.target</filename> to execute the
                 respective actions.</para>
 
-                <para>When these services are run they ensure that PID
+                <para>When these services are run, they ensure that PID
                 1 is replaced by the
                 <filename>/usr/lib/systemd/systemd-shutdown</filename>
                 tool which is then responsible for the actual
-                shutdown. Before shutting down this binary will try to
+                shutdown. Before shutting down, this binary will try to
                 unmount all remaining file systems, disable all
                 remaining swap devices, detach all remaining storage
                 devices and kill all remaining processes.</para>
 
+                <para>It is necessary to have this code in a separate binary
+                because otherwise rebooting after an upgrade might be broken —
+                the running PID 1 could still depend on libraries which are not
+                available any more, thus keeping the filesystem busy, which
+                then cannot be re-mounted read-only.</para>
+
                 <para>Immediately before executing the actual system
                 halt/poweroff/reboot/kexec
                 <filename>systemd-shutdown</filename> will run all