<filename>initrd-fs.target</filename>,
<filename>initrd-root-device.target</filename>,
<filename>initrd-root-fs.target</filename>,
+ <filename>initrd-usr-fs.target</filename>,
<filename>kbrequest.target</filename>,
<filename>kexec.target</filename>,
<filename>local-fs-pre.target</filename>,
<term><filename>initrd-fs.target</filename></term>
<listitem>
<para><citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- automatically adds dependencies of type
- <varname>Before=</varname> to
- <filename>sysroot-usr.mount</filename> and all mount points
- found in <filename>/etc/fstab</filename> that have
- <option>x-initrd.mount</option> and not have
- <option>noauto</option> mount options set.</para>
+ automatically adds dependencies of type <varname>Before=</varname> to
+ <filename>sysroot-usr.mount</filename> and all mount points found in
+ <filename>/etc/fstab</filename> that have the <option>x-initrd.mount</option> mount option set
+ and do not have the <option>noauto</option> mount option set. It is also indirectly ordered after
+ <filename>sysroot.mount</filename>. Thus, once this target is reached the
+ <filename>/sysroot/</filename> hierarchy is fully set up, in preparation for the transition to
+ the host OS.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><filename>initrd-root-fs.target</filename></term>
<listitem>
<para><citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- automatically adds dependencies of type
- <varname>Before=</varname> to the
- <filename>sysroot.mount</filename> unit, which is generated
- from the kernel command line.
- </para>
+ automatically adds dependencies of type <varname>Before=</varname> to the
+ <filename>sysroot.mount</filename> unit, which is generated from the kernel command line's
+ <varname>root=</varname> setting (or equivalent).</para>
+ </listitem>
+ </varlistentry>
+ <varlistentry>
+ <term><filename>initrd-usr-fs.target</filename></term>
+ <listitem>
+ <para><citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ automatically adds dependencies of type <varname>Before=</varname> to the
+ <filename>sysusr-usr.mount</filename> unit, which is generated from the kernel command line's
+ <varname>usr=</varname> switch. Services may order themselves after this target unit in order to
+ run once the <filename>/sysusr/</filename> hierarchy becomes available, on systems that come up
+ initially without a root file system, but with an initialized <filename>/usr/</filename> and need
+ to access that before setting up the root file system to ultimately switch to. On systems where
+ <varname>usr=</varname> is not used this target is ordered afer
+ <filename>sysroot.mount</filename> and thus mostly equivalent to
+ <filename>initrd-root-fs.target</filename>. In effect on any system once this target is reached
+ the file system backing <filename>/usr/</filename> is mounted, though possibly at two different
+ locations, either below the <filename>/sysusr/</filename> or the <filename>/sysroot/</filename>
+ hierarchies.</para>
</listitem>
</varlistentry>
<varlistentry>