man/systemd-mount.xml - main - niceSOFT/systemd

man/systemd-mount.xml
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Mike Yuan
mount-tool: never bind to device on explicit x-systemd.device-bound=no
03 мар 2025, 12:45
03 мар 2025, 12:45bb12d57
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->

<refentry id="systemd-mount"
          xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>systemd-mount</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd-mount</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd-mount</refname>
    <refname>systemd-umount</refname>
    <refpurpose>Establish and destroy transient mount or auto-mount points</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>systemd-mount</command>
      <arg choice="opt" rep="repeat"><replaceable>OPTIONS</replaceable></arg>
      <arg choice="plain"><replaceable>WHAT</replaceable></arg>
      <arg choice="opt"><replaceable>WHERE</replaceable></arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-mount</command>
      <arg choice="opt" rep="repeat"><replaceable>OPTIONS</replaceable></arg>
      <arg choice="plain"><option>--tmpfs</option></arg>
      <arg choice="opt"><replaceable>NAME</replaceable></arg>
      <arg choice="plain"><replaceable>WHERE</replaceable></arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-mount</command>
      <arg choice="opt" rep="repeat"><replaceable>OPTIONS</replaceable></arg>
      <arg choice="plain"><option>--list</option></arg>
    </cmdsynopsis>
    <cmdsynopsis>
      <command>systemd-mount</command>
      <arg choice="opt" rep="repeat"><replaceable>OPTIONS</replaceable></arg>
      <arg choice="plain"><option>--umount</option></arg>
      <arg choice="plain" rep="repeat"><replaceable>WHAT|WHERE</replaceable></arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><command>systemd-mount</command> may be used to create and start a transient <filename>.mount</filename> or
    <filename>.automount</filename> unit of the file system <replaceable>WHAT</replaceable> on the mount point
    <replaceable>WHERE</replaceable>.</para>

    <para>In many ways, <command>systemd-mount</command> is similar to the lower-level
    <citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry>
    command, however instead of executing the mount operation directly and immediately,
    <command>systemd-mount</command> schedules it through the service manager job queue, so that it may pull
    in further dependencies (such as parent mounts, or a file system checker to execute a priori), and may
    make use of the auto-mounting logic.</para>

    <para>The command takes either one or two arguments. If only one argument is specified it should refer to
    a block device or regular file containing a file system (e.g. <literal>/dev/sdb1</literal> or
    <literal>/path/to/disk.img</literal>). The block device or image file is then probed for a file system
    label and other metadata, and is mounted to a directory below <filename>/run/media/system/</filename>
    whose name is generated from the file system label. In this mode the block device or image file must
    exist at the time of invocation of the command, so that it may be probed. If the device is found to be a
    removable block device (e.g. a USB stick), an automount point is created instead of a regular mount point
    (i.e. the <option>--automount=</option> option is implied, see below). If the option
    <option>--tmpfs</option> is specified, then the argument is interpreted as the path where the new
    temporary file system shall be mounted.</para>

    <para>If two arguments are specified, the first indicates the mount source (the
    <replaceable>WHAT</replaceable>) and the second indicates the path to mount it on (the
    <replaceable>WHERE</replaceable>). In this mode no probing of the source is attempted, and a backing
    device node does not have to exist. However, if this mode is combined with <option>--discover</option>,
    device node probing for additional metadata is enabled, and – much like in the single-argument case
    discussed above – the specified device has to exist at the time of invocation of the command.</para>

    <para>Use the <option>--list</option> command to show a terse table of all local, known block devices with file
    systems that may be mounted with this command.</para>

    <para><command>systemd-umount</command> can be used to unmount a mount or automount point. It is the same
    as <command>systemd-mount</command> <option>--umount</option>.</para>
  </refsect1>

  <refsect1>
    <title>Options</title>

    <para>The following options are understood:</para>

    <variablelist>

      <varlistentry>
        <term><option>--no-block</option></term>

        <listitem>
          <para>Do not synchronously wait for the requested operation to finish. If this is not specified, the job will
          be verified, enqueued and <command>systemd-mount</command> will wait until the mount or automount unit's
          start-up is completed. By passing this argument, it is only verified and enqueued.</para>

          <xi:include href="version-info.xml" xpointer="v232"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-l</option></term>
        <term><option>--full</option></term>

        <listitem>
          <para>Do not ellipsize the output when <option>--list</option> is specified.</para>

        <xi:include href="version-info.xml" xpointer="v245"/>
        </listitem>
      </varlistentry>

      <xi:include href="standard-options.xml" xpointer="no-pager"/>
      <xi:include href="standard-options.xml" xpointer="no-legend" />
      <xi:include href="standard-options.xml" xpointer="no-ask-password"/>
      <xi:include href="standard-options.xml" xpointer="json"/>

      <varlistentry>
        <term><option>--quiet</option></term>
        <term><option>-q</option></term>

        <listitem><para>Suppresses additional informational output while running.</para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--discover</option></term>

        <listitem><para>Enable probing of the mount source. This switch is implied if a single argument is specified on
        the command line. If passed, additional metadata is read from the device to enhance the unit to create. For
        example, a descriptive string for the transient units is generated from the file system label and device
        model. Moreover, if a removable block device (e.g. USB stick) is detected an automount unit instead of a regular
        mount unit is created, with a short idle timeout, in order to ensure the file-system is placed in a clean
        state quickly after each access.</para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--type=</option></term>
        <term><option>-t</option></term>

        <listitem><para>Specifies the file system type to mount (e.g. <literal>vfat</literal> or
        <literal>ext4</literal>). If omitted or set to <literal>auto</literal>, the file system type is
        determined automatically.</para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--options=</option></term>
        <term><option>-o</option></term>

        <listitem><para>Additional mount options for the mount point.</para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--owner=<replaceable>USER</replaceable></option></term>

        <listitem><para>Let the specified user <replaceable>USER</replaceable> own the mounted file system.
        This is done by appending <option>uid=</option> and <option>gid=</option> options to the list
        of mount options. Only certain file systems support this option.</para>

        <xi:include href="version-info.xml" xpointer="v237"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--fsck=</option></term>

        <listitem><para>Takes a boolean argument, defaults to on. Controls whether to run a file system check
        immediately before the mount operation. In the automount case (see <option>--automount=</option> below) the
        check will be run the moment the first access to the device is made, which might slightly delay the
        access.</para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--description=</option></term>

        <listitem><para>Provide a description for the mount or automount unit. See <varname>Description=</varname> in
        <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
        </para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--property=</option></term>
        <term><option>-p</option></term>

        <listitem><para>Sets a unit property for the mount unit that is created. This takes an assignment in the same
        format as <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
        <command>set-property</command> command.</para>

        <xi:include href="version-info.xml" xpointer="v232"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--automount=</option></term>

        <listitem><para>Takes a boolean argument. Controls whether to create an automount point or a regular mount
        point. If true an automount point is created that is backed by the actual file system at the time of first
        access. If false a plain mount point is created that is backed by the actual file system immediately. Automount
        points have the benefit that the file system stays unmounted and hence in clean state until it is first
        accessed. In automount mode the <option>--timeout-idle-sec=</option> switch (see below) may be used to ensure
        the mount point is unmounted automatically after the last access and an idle period passed.</para>

        <para>If this switch is not specified, it defaults to false. If not specified and <option>--discover</option> is
        used (or only a single argument passed, which implies <option>--discover</option>, see above), and the file
        system block device is detected to be removable, it is set to true, in order to increase the chance that the
        file system is in a fully clean state if the device is unplugged abruptly.</para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-A</option></term>

        <listitem><para>Equivalent to <option>--automount=yes</option>.</para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--timeout-idle-sec=</option></term>

        <listitem><para>Takes a time value that controls the idle timeout in automount mode. If set to
        <literal>infinity</literal> (the default) no automatic unmounts are done. Otherwise, the file system backing the
        automount point is detached after the last access and the idle timeout passed. See
        <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details on
        the time syntax supported. This option has no effect if only a regular mount is established, and automounting
        is not used.</para>

        <para>Note that if <option>--discover</option> is used (or only a single argument passed, which implies
        <option>--discover</option>, see above), and the file system block device is detected to be removable,
        <option>--timeout-idle-sec=1s</option> is implied.</para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--automount-property=</option></term>

        <listitem><para>Similar to <option>--property=</option>, but applies additional properties to the automount
        unit created, instead of the mount unit.</para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--bind-device</option></term>

        <listitem><para>Controls whether the generated mount/automount unit shall be bound to the backing device's
        lifetime. This setting is especially useful in automount mode. If set, the units will be stopped automatically
        when the backing device vanishes. By default, the automount unit stays around, and subsequent accesses
        will block until backing device is replugged. This option has no effect in case of non-device mounts,
        such as network or virtual file system mounts.</para>

        <para>If <option>--discover</option> is used (or only a single argument passed, which implies
        <option>--discover</option>, see above), and the file system block device is detected to be removable,
        this option is implied.</para>

        <para>Note that mount units by default gain a <varname>Requires=</varname> dependency on
        the backing device. This behavior can be controlled via <option>x-systemd.device-bound=</option>
        mount option, see <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
        for details. In particular, <option>x-systemd.device-bound=no</option> takes precedence over this option,
        which suppresses device dependencies both in the generated mount units and what's implied by service manager.
        </para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--list</option></term>

        <listitem><para>Instead of establishing a mount or automount point, print a terse list of block devices
        containing file systems that may be mounted with <literal>systemd-mount</literal>, along with useful metadata
        such as labels, etc.</para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-u</option></term>
        <term><option>--umount</option></term>

        <listitem><para>Stop the mount and automount units corresponding to the specified mount points
        <replaceable>WHERE</replaceable> or the devices <replaceable>WHAT</replaceable>.
        <command>systemd-mount</command> with this option or <command>systemd-umount</command> can take multiple arguments
        which can be mount points, devices, <filename>/etc/fstab</filename> style node names, or backing files
        corresponding to loop devices, like
        <command>systemd-mount --umount /path/to/umount /dev/sda1 UUID=xxxxxx-xxxx LABEL=xxxxx /path/to/disk.img</command>.
        Note that when <option>-H</option> or <option>-M</option> is specified, only absolute paths to mount points are
        supported.</para>

        <xi:include href="version-info.xml" xpointer="v233"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-G</option></term>
        <term><option>--collect</option></term>

        <listitem><para>Unload the transient unit after it completed, even if it failed. Normally, without this option,
        all mount units that mount and failed are kept in memory until the user explicitly resets their failure state with
        <command>systemctl reset-failed</command> or an equivalent command. On the other hand, units that stopped
        successfully are unloaded immediately. If this option is turned on the "garbage collection" of units is more
        aggressive, and unloads units regardless of whether they exited successfully or failed. This option is a shortcut for
        <command>--property=CollectMode=inactive-or-failed</command>, see the explanation for
        <varname>CollectMode=</varname> in
        <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for further
        information.</para>

        <xi:include href="version-info.xml" xpointer="v236"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-T</option></term>
        <term><option>--tmpfs</option></term>

        <listitem>
          <para>Create and mount a new <constant>tmpfs</constant> file system on
          <replaceable>WHERE</replaceable>, with an optional <replaceable>NAME</replaceable> that defaults to
          <literal>tmpfs</literal>.</para>

          <para>The file system is mounted with the top-level directory mode determined by the
          <citerefentry><refentrytitle>umask</refentrytitle><manvolnum>2</manvolnum></citerefentry> setting
          of the caller, i.e. <constant>rwxrwxrwx</constant> masked by the umask of the caller. This matches
          what
          <citerefentry project='man-pages'><refentrytitle>mkdir</refentrytitle><manvolnum>1</manvolnum></citerefentry>
          does, but is different from the kernel default of <literal>rwxrwxrwxt</literal>, i.e. a
          world-writable directory with the sticky bit set.</para>

        <xi:include href="version-info.xml" xpointer="v255"/>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--canonicalize=</option></term>

        <listitem>
          <para>Controls whether the specified path shall be canonicalized on the client side before
          requesting the operation or not. Takes a boolean parameter, defaults to true. Note that for
          non-local operation (i.e. when <option>--machine=</option> or --<option>--host=</option> are used)
          canonicalization is implicitly turned off.</para>

          <para>Canonicalization of path entails resolving of symlinks, <literal>..</literal> path elements
          and <varname>LABEL=</varname>/<varname>UUID=</varname> style device node expansion. If
          canonicalization is disabled and the path contains a symlink element, <literal>..</literal>, or a
          <varname>LABEL=</varname>/<varname>UUID=</varname>/… expansion the operation will fail.</para>

          <xi:include href="version-info.xml" xpointer="v258"/>
        </listitem>
      </varlistentry>

      <xi:include href="user-system-options.xml" xpointer="user" />
      <xi:include href="user-system-options.xml" xpointer="system" />
      <xi:include href="user-system-options.xml" xpointer="host" />
      <xi:include href="user-system-options.xml" xpointer="machine" />

      <xi:include href="standard-options.xml" xpointer="help" />
      <xi:include href="standard-options.xml" xpointer="version" />
    </variablelist>

  </refsect1>

  <refsect1>
    <title>Exit status</title>

    <para>On success, 0 is returned, a non-zero failure
    code otherwise.</para>
  </refsect1>

  <refsect1>
    <title>The udev Database</title>

    <para>If <option>--discover</option> is used, <command>systemd-mount</command> honors a couple of additional udev
    properties of block devices:</para>

    <variablelist class='udev-directives'>
      <varlistentry>
        <term><varname>SYSTEMD_MOUNT_OPTIONS=</varname></term>

        <listitem><para>The mount options to use, if <option>--options=</option> is not used.</para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>SYSTEMD_MOUNT_WHERE=</varname></term>

        <listitem><para>The file system path to place the mount point at, instead of the automatically generated
        one.</para>

        <xi:include href="version-info.xml" xpointer="v232"/></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Example</title>

    <para>Use a udev rule like the following to automatically mount all USB storage plugged in:</para>

    <programlisting>ACTION=="add", SUBSYSTEMS=="usb", SUBSYSTEM=="block", ENV{ID_FS_USAGE}=="filesystem", \
        RUN{program}+="/usr/bin/systemd-mount --no-block --automount=yes --collect $devnode"</programlisting>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para><simplelist type="inline">
      <member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
      <member><citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd-run</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
    </simplelist></para>
  </refsect1>

</refentry>