mirror of
https://github.com/systemd/systemd.git
synced 2026-06-30 19:57:29 +00:00
9825195c25
Second StorageProvider implementation, exposing regular files and directories from a backing filesystem. In system mode the backing directory is /var/lib/storage/, in user mode $XDG_STATE_HOME/storage/; entries with a .volume suffix are exposed, with the inode type determining whether the volume is reported as reg, dir or (via symlinked/bind-mounted device node) blk. Unlike the block provider, this one supports creating volumes on-demand from a small set of built-in templates: sparse-file, allocated-file, directory and subvolume.
200 lines
8.6 KiB
XML
200 lines
8.6 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
|
|
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd">
|
|
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
|
|
|
|
<refentry id="systemd-storage-fs_.service"
|
|
xmlns:xi="http://www.w3.org/2001/XInclude">
|
|
|
|
<refentryinfo>
|
|
<title>systemd-storage-fs@.service</title>
|
|
<productname>systemd</productname>
|
|
</refentryinfo>
|
|
|
|
<refmeta>
|
|
<refentrytitle>systemd-storage-fs@.service</refentrytitle>
|
|
<manvolnum>8</manvolnum>
|
|
</refmeta>
|
|
|
|
<refnamediv>
|
|
<refname>systemd-storage-fs@.service</refname>
|
|
<refname>systemd-storage-fs.socket</refname>
|
|
<refname>systemd-storage-fs</refname>
|
|
<refpurpose>Storage provider exposing regular files and directories as storage volumes</refpurpose>
|
|
</refnamediv>
|
|
|
|
<refsynopsisdiv>
|
|
<para><filename>systemd-storage-fs@.service</filename></para>
|
|
<para><filename>systemd-storage-fs.socket</filename></para>
|
|
</refsynopsisdiv>
|
|
|
|
<refsect1>
|
|
<title>Description</title>
|
|
|
|
<para><filename>systemd-storage-fs@.service</filename> is a service that implements the
|
|
<constant>io.systemd.StorageProvider</constant> <ulink url="https://varlink.org/">Varlink</ulink>
|
|
interface, exposing regular files and directories in <filename>/var/lib/storage/*.volume</filename> (if
|
|
used in system mode) or <filename>$XDG_STATE_HOME/storage</filename> (when used in user mode) as storage
|
|
volumes. Acquired volumes are returned to the caller as file descriptors. Unlike
|
|
<citerefentry><refentrytitle>systemd-storage-block@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
|
this implementation also supports creating new volumes on demand from a small set of built-in
|
|
templates.</para>
|
|
|
|
<para>The service is socket-activated via <filename>systemd-storage-fs.socket</filename>. In system mode
|
|
it listens on the AF_UNIX socket <filename>/run/systemd/io.systemd.StorageProvider/fs</filename>, in user
|
|
mode on <filename>$XDG_RUNTIME_DIR/systemd/io.systemd.StorageProvider/fs</filename>. See
|
|
<citerefentry><refentrytitle>storagectl</refentrytitle><manvolnum>1</manvolnum></citerefentry> for an
|
|
enumeration tool.</para>
|
|
|
|
<para>See also
|
|
<citerefentry><refentrytitle>systemd-storage-block@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
for a complementary implementation that exposes local block devices as storage volumes.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Volumes</title>
|
|
|
|
<para>Volumes are stored below the storage directory:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem><para><filename>/var/lib/storage/</filename> when run in system mode.</para></listitem>
|
|
|
|
<listitem><para><filename>$XDG_STATE_HOME/storage/</filename> (typically
|
|
<filename>~/.local/state/storage/</filename>) when run in user mode.</para></listitem>
|
|
</itemizedlist>
|
|
|
|
<para>Each volume on disk is stored as a directory entry with a <filename>.volume</filename> suffix in
|
|
the storage directory. Entries which are regular files are exposed as volumes of type
|
|
<constant>reg</constant>; entries which are directories are exposed as volumes of type
|
|
<constant>dir</constant>. Moreover, block device nodes may be symlinked (or bind mounted) into the
|
|
directory, which are then exposed as volumes of type <constant>blk</constant>.</para>
|
|
|
|
<para>For directory volumes, the root of the file system passed to clients is placed in a subdirectory
|
|
<filename>root/</filename> of the <filename><replaceable>NAME</replaceable>.volume</filename> directory. The former (and all inodes
|
|
below it) must be owned by the foreign UID range, the latter by the host's root.</para>
|
|
|
|
<para>When acquiring a volume, symlinks are followed.</para>
|
|
|
|
<para>An administrator is permitted to freely manipulate the volume hierarchy directly as long as the
|
|
rules described above are followed. In particular, it's permitted to copy, mount or symlink arbitrary
|
|
external resources (regardless if directory, regular file or block) into the volume directory, so that
|
|
they are exposed as additional volumes.</para>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Templates</title>
|
|
|
|
<para>The provider supports creating new volumes automatically when they are acquired. The caller may
|
|
select a <emphasis>template</emphasis> that determines configuration details of the volume to create. The
|
|
following built-in templates are available:</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><constant>sparse-file</constant></term>
|
|
|
|
<listitem><para>Creates a volume backed by a sparsely populated regular file. This is the default
|
|
template when creating a regular file volume. (Volume type is <literal>reg</literal>.)</para>
|
|
|
|
<xi:include href="version-info.xml" xpointer="v261"/></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><constant>allocated-file</constant></term>
|
|
|
|
<listitem><para>Creates a volume backed by a fully allocated regular file. (Volume type is
|
|
<literal>reg</literal>.)</para>
|
|
|
|
<xi:include href="version-info.xml" xpointer="v261"/></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><constant>directory</constant></term>
|
|
|
|
<listitem><para>Creates a volume backed by a regular directory. (Volume type is
|
|
<literal>dir</literal>.)</para>
|
|
|
|
<xi:include href="version-info.xml" xpointer="v261"/></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><constant>subvolume</constant></term>
|
|
|
|
<listitem><para>Creates a btrfs subvolume as backing inode (falling back to a regular directory if
|
|
the storage directory is not on btrfs). This is the default template when creating a directory
|
|
volume. (Volume type is <literal>dir</literal>.)</para>
|
|
|
|
<xi:include href="version-info.xml" xpointer="v261"/></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Options</title>
|
|
|
|
<para>The following command-line options are understood:</para>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><option>--system</option></term>
|
|
|
|
<listitem><para>Operate in system mode. Volumes are stored below
|
|
<filename>/var/lib/storage/</filename>. This is the default when invoked from
|
|
<filename>systemd-storage-fs@.service</filename> in the system manager.</para>
|
|
|
|
<xi:include href="version-info.xml" xpointer="v261"/></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><option>--user</option></term>
|
|
|
|
<listitem><para>Operate in user mode. Volumes are stored below
|
|
<filename>$XDG_STATE_HOME/storage/</filename>. This is the default when invoked from
|
|
<filename>systemd-storage-fs@.service</filename> in the user manager.</para>
|
|
|
|
<xi:include href="version-info.xml" xpointer="v261"/></listitem>
|
|
</varlistentry>
|
|
|
|
<xi:include href="standard-options.xml" xpointer="help" />
|
|
<xi:include href="standard-options.xml" xpointer="version" />
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>Files</title>
|
|
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><filename>/var/lib/storage/</filename></term>
|
|
<term><filename>$XDG_STATE_HOME/storage/</filename></term>
|
|
|
|
<listitem><para>The storage directory used to back the system mode and user mode service
|
|
instances respectively. Each volume is stored as an entry with a
|
|
<filename>.volume</filename> suffix below this directory.</para>
|
|
|
|
<xi:include href="version-info.xml" xpointer="v261"/></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><filename>/run/systemd/io.systemd.StorageProvider/fs</filename></term>
|
|
<term><filename>$XDG_RUNTIME_DIR/systemd/io.systemd.StorageProvider/fs</filename></term>
|
|
|
|
<listitem><para>AF_UNIX sockets the service listens on, in system and user mode
|
|
respectively. These are the canonical locations for the <literal>fs</literal> storage
|
|
provider, and are enumerated by <command>storagectl providers</command>.</para>
|
|
|
|
<xi:include href="version-info.xml" xpointer="v261"/></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
<para><simplelist type="inline">
|
|
<member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
|
|
<member><citerefentry><refentrytitle>storagectl</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
|
|
<member><citerefentry><refentrytitle>systemd-storage-block@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry></member>
|
|
</simplelist></para>
|
|
</refsect1>
|
|
|
|
</refentry>
|