"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
+ SPDX-License-Identifier: LGPL-2.1+
+
This file is part of systemd.
Copyright 2010 Lennart Poettering
for kernel-to-userspace and userspace-to-userspace interfaces. Some
of them may not be changed via mount units, and cannot be
disabled. For a longer discussion see <ulink
- url="http://www.freedesktop.org/wiki/Software/systemd/APIFileSystems">API
+ url="https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems">API
File Systems</ulink>.</para>
</refsect1>
<refsect1>
- <title>Automatic Dependencies</title>
-
- <para>If a mount unit is beneath another mount unit in the file
- system hierarchy, both a requirement dependency and an ordering
- dependency between both units are created automatically.</para>
-
- <para>Block device backed file systems automatically gain
- <varname>BindsTo=</varname> and <varname>After=</varname> type
- dependencies on the device unit encapsulating the block
- device (see below).</para>
-
- <para>If traditional file system quota is enabled for a mount
- unit, automatic <varname>Wants=</varname> and
- <varname>Before=</varname> dependencies on
- <filename>systemd-quotacheck.service</filename> and
- <filename>quotaon.service</filename> are added.</para>
-
- <para>For mount units with <varname>DefaultDependencies=yes</varname> in the <literal>[Unit]</literal> section (the
- default) a couple additional dependencies are added. Mount units referring to local file systems automatically gain
- an <varname>After=</varname> dependency on <filename>local-fs-pre.target</filename>. Network mount units
- automatically acquire <varname>After=</varname> dependencies on <filename>remote-fs-pre.target</filename>,
- <filename>network.target</filename> and <filename>network-online.target</filename>. Towards the latter a
- <varname>Wants=</varname> unit is added as well. Mount units referring to local and network file systems are
+ <title>Implicit Dependencies</title>
+
+ <para>The following dependencies are implicitly added:</para>
+
+ <itemizedlist>
+ <listitem><para>If a mount unit is beneath another mount unit in the file
+ system hierarchy, both a requirement dependency and an ordering
+ dependency between both units are created automatically.</para></listitem>
+
+ <listitem><para>Block device backed file systems automatically gain
+ <varname>BindsTo=</varname> and <varname>After=</varname> type
+ dependencies on the device unit encapsulating the block
+ device (see below).</para></listitem>
+
+ <listitem><para>If traditional file system quota is enabled for a mount
+ unit, automatic <varname>Wants=</varname> and
+ <varname>Before=</varname> dependencies on
+ <filename>systemd-quotacheck.service</filename> and
+ <filename>quotaon.service</filename> are added.</para></listitem>
+
+ <listitem><para>Additional implicit dependencies may be added as result of
+ execution and resource control parameters as documented in
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ and
+ <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+ </para></listitem>
+ </itemizedlist>
+ </refsect1>
+
+ <refsect1>
+ <title>Default Dependencies</title>
+
+ <para>The following dependencies are added unless <varname>DefaultDependencies=no</varname> is set:</para>
+
+ <itemizedlist>
+ <listitem><para>All mount units acquire automatic <varname>Before=</varname> and <varname>Conflicts=</varname> on
+ <filename>umount.target</filename> in order to be stopped during shutdown.</para></listitem>
+
+ <listitem><para>Mount units referring to local file systems automatically gain
+ an <varname>After=</varname> dependency on <filename>local-fs-pre.target</filename>.</para></listitem>
+
+ <listitem><para>Network mount units
+ automatically acquire <varname>After=</varname> dependencies on <filename>remote-fs-pre.target</filename>,
+ <filename>network.target</filename> and <filename>network-online.target</filename>. Towards the latter a
+ <varname>Wants=</varname> unit is added as well.</para></listitem>
+ </itemizedlist>
+
+ <para>Mount units referring to local and network file systems are
distinguished by their file system type specification. In some cases this is not sufficient (for example network
block device based mounts, such as iSCSI), in which case <option>_netdev</option> may be added to the mount option
- string of the unit, which forces systemd to consider the mount unit a network mount. Mount units (regardless if
- local or network) also acquire automatic <varname>Before=</varname> and <varname>Conflicts=</varname> on
- <filename>umount.target</filename> in order to be stopped during shutdown.</para>
-
- <para>Additional implicit dependencies may be added as result of
- execution and resource control parameters as documented in
- <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- and
- <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+ string of the unit, which forces systemd to consider the mount unit a network mount.</para>
</refsect1>
<refsect1>
<para>The NFS mount option <option>bg</option> for NFS background mounts
as documented in <citerefentry project='man-pages'><refentrytitle>nfs</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- is not supported in <filename>/etc/fstab</filename> entries. The systemd mount option <option>nofail</option>
- provides similar functionality and should be used instead.</para>
+ is detected by <command>systemd-fstab-generator</command> and the options
+ are transformed so that systemd fulfills the job-control implications of
+ that option. Specifically <command>systemd-fstab-generator</command> acts
+ as though <literal>x-systemd.mount-timout=infinity,retry=10000</literal> was
+ prepended to the option list, and <literal>fg,nofail</literal> was appended.
+ Depending on specific requirements, it may be appropriate to provide some of
+ these options explicitly, or to make use of the
+ <literal>x-systemd.automount</literal> option described below instead
+ of using <literal>bg</literal>.</para>
<para>When reading <filename>/etc/fstab</filename> a few special
mount options are understood by systemd which influence how
for details.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>x-systemd.before=</option></term>
+ <term><option>x-systemd.after=</option></term>
+
+ <listitem><para>Configures a <varname>Before=</varname>
+ dependency or <varname>After=</varname> between the created
+ mount unit and another systemd unit, such as a mount unit.
+ The argument should be a unit name or an absolute path
+ to a mount point. This option may be specified more than once.
+ This option is particularly useful for mount point declarations
+ with <option>nofail</option> option that are mounted
+ asynchronously but need to be mounted before or after some unit
+ start, for example, before <filename>local-fs.target</filename>
+ unit.
+ See <varname>Before=</varname> and <varname>After=</varname> in
+ <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details.</para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><option>x-systemd.requires-mounts-for=</option></term>
<listitem><para>The block device backed file system will be upgraded
to <varname>BindsTo=</varname> dependency. This option is only useful
when mounting file systems manually with
- <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+ <citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
as the default dependency in this case is <varname>Requires=</varname>.
This option is already implied by entries in <filename>/etc/fstab</filename>
or by mount units.
details.</para>
</listitem>
</varlistentry>
+
+ <varlistentry>
+ <term><option>_netdev</option></term>
+
+ <listitem><para>Normally the file system type is used to determine if a
+ mount is a "network mount", i.e. if it should only be started after the
+ network is available. Using this option overrides this detection and
+ specifies that the mount requires network.</para>
+
+ <para>Network mount units are ordered between <filename>remote-fs-pre.target</filename>
+ and <filename>remote-fs.target</filename>, instead of
+ <filename>local-fs-pre.target</filename> and <filename>local-fs.target</filename>.
+ They also pull in <filename>network-online.target</filename> and are ordered after
+ it and <filename>network.target</filename>.</para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><option>noauto</option></term>
<term><option>auto</option></term>
- <listitem><para>With <option>noauto</option>, this mount will
- not be added as a dependency for
- <filename>local-fs.target</filename> or
- <filename>remote-fs.target</filename>. This means that it will
- not be mounted automatically during boot, unless it is pulled
- in by some other unit. The <option>auto</option> option has the
- opposite meaning and is the default.</para>
+ <listitem><para>With <option>noauto</option>, the mount unit will not be added as a dependency for
+ <filename>local-fs.target</filename> or <filename>remote-fs.target</filename>. This means that it will not be
+ mounted automatically during boot, unless it is pulled in by some other unit. The <option>auto</option> option
+ has the opposite meaning and is the default. Note that the <option>noauto</option> option has an effect on the
+ mount unit itself only — if <option>x-systemd.automount</option> is used (see above), then the matching
+ automount unit will still be pulled in by these targets.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>Where=</varname></term>
- <listitem><para>Takes an absolute path of a directory of the
- mount point. If the mount point does not exist at the time of
+ <listitem><para>Takes an absolute path of a directory for the
+ mount point; in particular, the destination cannot be a symbolic
+ link. If the mount point does not exist at the time of
mounting, it is created. This string must be reflected in the
unit filename. (See above.) This option is
mandatory.</para></listitem>
projects / thirdparty / systemd.git / blobdiff