Added instructions to unmount $LFS/proc and $LFS before rebooting

git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@580 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

chapter08/reboot.xml

@@ -3,11 +3,35 @@
 
 <para>
 Now that all software has been installed, bootscripts have been created, 
-it's time to reboot the computer. Run a command like
-<userinput>/sbin/shutdown -r now</userinput> or
-<userinput>/sbin/reboot</userinput> to reboot your system and at the
-LILO: prompt make sure that you tell it to boot
-<emphasis>lfs</emphasis>.
+it's time to reboot the computer. Before we reboot let's exit the
+chroot'ed environment first and unmount the LFS partition by running:
+</para>
+
+<blockquote><literallayout>
+	<userinput>logout</userinput>
+	<userinput>umount $LFS/proc &amp;&amp;</userinput>
+	<userinput>umount $LFS</userinput>
+</blockquote></literallayout>
+
+<para>
+If your LFS system consists of more than the one partition we have been
+assuming for simplicity's sake, unmount those before you try to unmount
+$LFS (ie: you can't unmount $LFS while you have something mounted on
+$LFS/usr for example).
+</para>
+
+<para>
+And you can reboot your system by running something like:
+</para>
+
+<blockquote><literallayout>
+	<userinput>/sbin/shutdown -r now</userinput>
+</literallayout></blockquote>
+
+<para>
+At the LILO: prompt make sure that you tell it to boot 
+<emphasis>lfs</emphasis> and not the default entry which will boot your
+host system again.
 </para>
 
 <para>