Merge pull request #1854 from poettering/unit-deps

Dependency engine improvements

14 files changed, 312 insertions, 67 deletions

diff --git a/man/systemd.automount.xml b/man/systemd.automount.xml
index 26a0f291dd..1b0ae832da 100644
--- a/man/systemd.automount.xml
+++ b/man/systemd.automount.xml
@@ -85,10 +85,24 @@
 
     <para>Automount units may be used to implement on-demand mounting
     as well as parallelized mounting of file systems.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>If an automount unit is beneath another mount unit in the
+    file system hierarchy, both a requirement and an ordering
+    dependency between both units are created automatically.</para>
+
+    <para>An implicit <varname>Before=</varname> dependency is created
+    between an automount unit and the mount unit it activates.</para>
+
+    <para>Automount units acquire automatic <varname>Before=</varname>
+    and <varname>Conflicts=</varname> on
+    <filename>umount.target</filename> in order to be stopped during
+    shutdown, unless <varname>DefaultDependencies=no</varname> is
+    set.</para>
 
-    <para>If an automount point is beneath another mount point in the
-    file system hierarchy, a dependency between both units is created
-    automatically.</para>
   </refsect1>
 
   <refsect1>
diff --git a/man/systemd.device.xml b/man/systemd.device.xml
index ac6deafb18..effed098dd 100644
--- a/man/systemd.device.xml
+++ b/man/systemd.device.xml
@@ -83,7 +83,18 @@
     the escaping logic used to convert a file system path to a unit
     name see
     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+  </refsect1>
 
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Many unit types automatically acquire dependencies on device
+    units of devices they require. For example,
+    <filename>.socket</filename> unit acquire dependencies on the
+    device units of the network interface specified in
+    <varname>BindToDevice=</varname>. Similar, swap and mount units
+    acquire dependencies on the units encapsulating their backing
+    block devices.</para>
   </refsect1>
 
   <refsect1>
diff --git a/man/systemd.exec.xml b/man/systemd.exec.xml
index 5bb97bd98e..6dda6c5e69 100644
--- a/man/systemd.exec.xml
+++ b/man/systemd.exec.xml
@@ -77,6 +77,31 @@
   </refsect1>
 
   <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>A few execution parameters result in additional, automatic
+    dependencies to be added.</para>
+
+    <para>Units with <varname>WorkingDirectory=</varname> or
+    <varname>RootDirectory=</varname> set automatically gain
+    dependencies of type <varname>Requires=</varname> and
+    <varname>After=</varname> on all mount units required to access
+    the specified paths. This is equivalent to having them listed
+    explicitly in <varname>RequiresMountsFor=</varname>.</para>
+
+    <para>Similar, units with <varname>PrivateTmp=</varname> enabled
+    automatically get mount unit dependencies for all mounts
+    required to access <filename>/tmp</filename> and
+    <filename>/var/tmp</filename>.</para>
+
+    <para>Units whose output standard output or error output is
+    connected to any other sink but <option>null</option>,
+    <option>tty</option> and <option>socket</option> automatically
+    acquire dependencies of type <varname>After=</varname> on
+    <filename>journald.socket</filename>.</para>
+  </refsect1>
+
+  <refsect1>
     <title>Options</title>
 
     <variablelist class='unit-directives'>
@@ -93,7 +118,9 @@
         and the respective user's home directory if run as user. If
         the setting is prefixed with the <literal>-</literal>
         character, a missing working directory is not considered
-        fatal.</para></listitem>
+        fatal. Note that setting this parameter might result in
+        additional dependencies to be added to the unit (see
+        above).</para></listitem>
       </varlistentry>
 
       <varlistentry>
@@ -104,7 +131,9 @@
         project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
         system call. If this is used, it must be ensured that the
         process binary and all its auxiliary files are available in
-        the <function>chroot()</function> jail.</para></listitem>
+        the <function>chroot()</function> jail. Note that setting this
+        parameter might result in additional dependencies to be added
+        to the unit (see above).</para></listitem>
       </varlistentry>
 
       <varlistentry>
@@ -378,6 +407,7 @@
         <para>This setting defaults to
         <option>null</option>.</para></listitem>
       </varlistentry>
+
       <varlistentry>
         <term><varname>StandardOutput=</varname></term>
         <listitem><para>Controls where file descriptor 1 (STDOUT) of
@@ -443,8 +473,11 @@
         <para>This setting defaults to the value set with
         <option>DefaultStandardOutput=</option> in
         <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-        which defaults to <option>journal</option>.</para></listitem>
+        which defaults to <option>journal</option>. Note that setting
+        this parameter might result in additional dependencies to be
+        added to the unit (see above).</para></listitem>
       </varlistentry>
+
       <varlistentry>
         <term><varname>StandardError=</varname></term>
         <listitem><para>Controls where file descriptor 2 (STDERR) of
@@ -455,8 +488,11 @@
         standard error. This setting defaults to the value set with
         <option>DefaultStandardError=</option> in
         <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-        which defaults to <option>inherit</option>.</para></listitem>
+        which defaults to <option>inherit</option>. Note that setting
+        this parameter might result in additional dependencies to be
+        added to the unit (see above).</para></listitem>
       </varlistentry>
+
       <varlistentry>
         <term><varname>TTYPath=</varname></term>
         <listitem><para>Sets the terminal device node to use if
diff --git a/man/systemd.mount.xml b/man/systemd.mount.xml
index dd6b7a51a8..67e96dc157 100644
--- a/man/systemd.mount.xml
+++ b/man/systemd.mount.xml
@@ -94,10 +94,6 @@
     unit, to allow on-demand or parallelized mounting. See
     <citerefentry><refentrytitle>systemd.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 
-    <para>If a mount point is beneath another mount point in the file
-    system hierarchy, a dependency between both units is created
-    automatically.</para>
-
     <para>Mount points created at runtime (independently of unit files
     or <filename>/etc/fstab</filename>) will be monitored by systemd
     and appear like any other mount unit in systemd. See
@@ -114,6 +110,52 @@
   </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> (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 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>
+  </refsect1>
+
+  <refsect1>
     <title><filename>fstab</filename></title>
 
     <para>Mount units may either be configured via unit files, or via
@@ -130,7 +172,7 @@
     <para>When reading <filename>/etc/fstab</filename> a few special
     mount options are understood by systemd which influence how
     dependencies are created for mount points. systemd will create a
-    dependency of type <option>Wants</option> or
+    dependency of type <varname>Wants=</varname> or
     <option>Requires</option> (see option <option>nofail</option>
     below), from either <filename>local-fs.target</filename> or
     <filename>remote-fs.target</filename>, depending whether the file
diff --git a/man/systemd.path.xml b/man/systemd.path.xml
index d02bc92ae6..1bd65ce86d 100644
--- a/man/systemd.path.xml
+++ b/man/systemd.path.xml
@@ -79,13 +79,24 @@
     limitations as inotify, and for example cannot be used to monitor
     files or directories changed by other machines on remote NFS file
     systems.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>If a path unit is beneath another mount unit in the file
+    system hierarchy, both a requirement and an ordering dependency
+    between both units are created automatically.</para>
 
-    <para>If a path unit is beneath another mount point in the file
-    system hierarchy, a dependency between both units is created
-    automatically.</para>
+    <para>An implicit <varname>Before=</varname> dependency is added
+    between a path unit and the unit it is supposed to activate.</para>
 
     <para>Unless <varname>DefaultDependencies=false</varname> is used,
     path units will implicitly have dependencies of type
+    <varname>Before=</varname> on <filename>paths.target</filename>,
+    dependencies of type <varname>After=</varname> and
+    <varname>Requires=</varname> on
+    <filename>sysinit.target</filename>, and have dependencies of type
     <varname>Conflicts=</varname> and <varname>Before=</varname> on
     <filename>shutdown.target</filename>. These ensure that path units
     are terminated cleanly prior to system shutdown. Only path units
diff --git a/man/systemd.resource-control.xml b/man/systemd.resource-control.xml
index 164adb938a..0497f60546 100644
--- a/man/systemd.resource-control.xml
+++ b/man/systemd.resource-control.xml
@@ -90,6 +90,15 @@
   </refsect1>
 
   <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Units with the <varname>Slice=</varname> setting set get
+    automatic <varname>Requires=</varname> and
+    <varname>After=</varname> dependencies on the specified slice
+    unit.</para>
+  </refsect1>
+
+  <refsect1>
     <title>Options</title>
 
     <para>Units of the types listed above can have settings
diff --git a/man/systemd.scope.xml b/man/systemd.scope.xml
index fd65a851e2..f69b2ef635 100644
--- a/man/systemd.scope.xml
+++ b/man/systemd.scope.xml
@@ -72,6 +72,10 @@
     url="http://www.freedesktop.org/wiki/Software/systemd/ControlGroupInterface/">New
     Control Group Interfaces</ulink> for an introduction on how to make
     use of scope units from programs.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
 
     <para>Unless <varname>DefaultDependencies=false</varname>
     is used, scope units will implicitly have dependencies of
@@ -82,6 +86,11 @@
     shutdown. Only scope units involved with early boot or
     late system shutdown should disable this option.
     </para>
+
+    <para>Additional implicit dependencies may be added as result of
+    resource control parameters as documented in
+    <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+
   </refsect1>
 
   <refsect1>
diff --git a/man/systemd.service.xml b/man/systemd.service.xml
index 4e5098f0e1..c6ed75d158 100644
--- a/man/systemd.service.xml
+++ b/man/systemd.service.xml
@@ -1,4 +1,4 @@
-<?xml version='1.0'?> <!--*-nxml-*-->
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
 
@@ -77,18 +77,6 @@
     which configure resource control settings for the processes of the
     service.</para>
 
-    <para>Unless <varname>DefaultDependencies=</varname> is set to
-    <option>false</option>, service units will implicitly have
-    dependencies of type <varname>Requires=</varname> and
-    <varname>After=</varname> on <filename>basic.target</filename> as
-    well as dependencies of type <varname>Conflicts=</varname> and
-    <varname>Before=</varname> on
-    <filename>shutdown.target</filename>. These ensure that normal
-    service units pull in basic system initialization, and are
-    terminated cleanly prior to system shutdown. Only services
-    involved with early boot or late system shutdown should disable
-    this option.</para>
-
     <para>If a service is requested under a certain name but no unit
     configuration file is found, systemd looks for a SysV init script
     by the same name (with the <filename>.service</filename> suffix
@@ -97,8 +85,39 @@
     compatibility is quite comprehensive but not 100%. For details
     about the incompatibilities, see the <ulink
     url="http://www.freedesktop.org/wiki/Software/systemd/Incompatibilities">Incompatibilities
-    with SysV</ulink> document.
-    </para>
+    with SysV</ulink> document.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Services with <varname>Type=dbus</varname> set automatically
+    acquire dependencies of type <varname>Requires=</varname> and
+    <varname>After=</varname> on
+    <filename>dbus.socket</filename>.</para>
+
+    <para>Socket activated service are automatically ordered after
+    their activated <filename>.socket</filename> units via an
+    automatic <varname>After=</varname> dependency.</para>
+
+    <para>Unless <varname>DefaultDependencies=</varname> is set to
+    <option>false</option>, service units will implicitly have
+    dependencies of type <varname>Requires=</varname> and
+    <varname>After=</varname> on <filename>sysinit.target</filename>,
+    a dependency of type <varname>After=</varname> on
+    <filename>basic.target</filename> as well as dependencies of
+    type <varname>Conflicts=</varname> and <varname>Before=</varname>
+    on <filename>shutdown.target</filename>. These ensure that normal
+    service units pull in basic system initialization, and are
+    terminated cleanly prior to system shutdown. Only services
+    involved with early boot or late system shutdown should disable
+    this option.</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>
   </refsect1>
 
   <refsect1>
diff --git a/man/systemd.slice.xml b/man/systemd.slice.xml
index 87c2a3bce3..5c87bf0260 100644
--- a/man/systemd.slice.xml
+++ b/man/systemd.slice.xml
@@ -97,6 +97,14 @@
     url="http://www.freedesktop.org/wiki/Software/systemd/ControlGroupInterface/">New
     Control Group Interfaces</ulink> for an introduction on how to make
     use of slice units from programs.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Slice units automatically gain dependencies of type
+    <varname>After=</varname> and <varname>Requires=</varname> on
+    their immediate parent slice unit.</para>
 
     <para>Unless <varname>DefaultDependencies=false</varname>
     is used, slice units will implicitly have dependencies of
diff --git a/man/systemd.socket.xml b/man/systemd.socket.xml
index 410886f841..beac053bf0 100644
--- a/man/systemd.socket.xml
+++ b/man/systemd.socket.xml
@@ -134,6 +134,40 @@
   </refsect1>
 
   <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Socket units automatically gain a <varname>Before=</varname>
+    dependency on the service units they activate.</para>
+
+    <para>Socket units referring to file system paths (such as AF_UNIX
+    sockets or FIFOs) implicitly gain <varname>Requires=</varname> and
+    <varname>After=</varname> dependencies on all mount units
+    necessary to access those paths.</para>
+
+    <para>Socket units using the <varname>BindToDevice=</varname>
+    setting automatically gain a <varname>BindsTo=</varname> and
+    <varname>After=</varname> dependency on the device unit
+    encapsulating the specified network interface.</para>
+
+    <para>If <varname>DefaultDependencies=yes</varname> is set (the
+    default), socket units automatically gain a
+    <varname>Before=</varname> dependency on
+    <filename>sockets.target</filename>. They also gain a pair of
+    <varname>After=</varname> and <varname>Requires=</varname>
+    dependency on <filename>sysinit.target</filename>, and a pair of
+    <varname>Before=</varname> and <varname>Conflicts=</varname>
+    dependencies on <filename>shutdown.target</filename>. These
+    dependencies ensure that the socket unit is started before normal
+    services at boot, and is stopped on 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>
+  </refsect1>
+
+  <refsect1>
     <title>Options</title>
 
     <para>Socket files must include a [Socket] section, which carries
@@ -309,12 +343,14 @@
         <listitem><para>Specifies a network interface name to bind
         this socket to. If set, traffic will only be accepted from the
         specified network interfaces. This controls the
-        SO_BINDTODEVICE socket option (see
-        <citerefentry project='man-pages'><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+        SO_BINDTODEVICE socket option (see <citerefentry
+        project='man-pages'><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
         for details). If this option is used, an automatic dependency
         from this socket unit on the network interface device unit
         (<citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>
-        is created.</para></listitem>
+        is created. Note that setting this parameter might result in
+        additional dependencies to be added to the unit (see
+        above).</para></listitem>
       </varlistentry>
 
       <varlistentry>
@@ -719,7 +755,9 @@
         with <varname>Accept=no</varname>. It defaults to the service
         that bears the same name as the socket (with the suffix
         replaced). In most cases, it should not be necessary to use
-        this option.</para></listitem>
+        this option. Note that setting this parameter might result in
+        additional dependencies to be added to the unit (see
+        above).</para></listitem>
       </varlistentry>
 
       <varlistentry>
diff --git a/man/systemd.swap.xml b/man/systemd.swap.xml
index bc9ef826e1..c600405c87 100644
--- a/man/systemd.swap.xml
+++ b/man/systemd.swap.xml
@@ -68,14 +68,15 @@
 
     <para>Additional options are listed in
     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-    which define the execution environment the
-    <citerefentry project='man-pages'><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry>
-    binary is executed in, and in
+    which define the execution environment the <citerefentry
+    project='man-pages'><refentrytitle>swapon</refentrytitle><manvolnum>8</manvolnum></citerefentry>
+    binary is executed in, in
     <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-    which define the way the processes are terminated, and in
+    which define the way the these processes are
+    terminated, and in
     <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-    which configure resource control settings for the processes of the
-    service.</para>
+    which configure resource control settings for these processes of the
+    unit.</para>
 
     <para>Swap units must be named after the devices
     or files they control. Example: the swap device
@@ -84,15 +85,28 @@
     the escaping logic used to convert a file system path to a unit
     name, see
     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
 
-    <para>All swap units automatically get the appropriate
-    dependencies on the devices or on the mount points of the files
+    <para>All swap units automatically get the
+    <varname>BindsTo=</varname> and <varname>After=</varname>
+    dependencies on the device units or the mount units of the files
     they are activated from.</para>
 
     <para>Swap units with <varname>DefaultDependencies=</varname>
-    enabled implicitly acquire a conflicting dependency to
+    enabled implicitly acquire a <varname>Conflicts=</varname> and an
+    <varname>After=</varname> dependency on
     <filename>umount.target</filename> so that they are deactivated at
-    shutdown.</para>
+    shutdown, unless <varname>DefaultDependencies=no</varname> is
+    specified.</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>
   </refsect1>
 
   <refsect1>
diff --git a/man/systemd.target.xml b/man/systemd.target.xml
index e790e9b77a..54a5f5035c 100644
--- a/man/systemd.target.xml
+++ b/man/systemd.target.xml
@@ -77,15 +77,20 @@
     See
     <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
     for details).</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
 
     <para>Unless <varname>DefaultDependencies=</varname> is set to
-    <option>false</option>, target units will implicitly complement
-    all configured dependencies of type <varname>Wants=</varname>,
+    <option>no</option>, target units will implicitly complement all
+    configured dependencies of type <varname>Wants=</varname>,
     <varname>Requires=</varname>,
     <varname>RequiresOverridable=</varname> with dependencies of type
-    <varname>After=</varname> if the units in question also have
-    <varname>DefaultDependencies=true</varname>.
-    </para>
+    <varname>After=</varname>, unless an ordering dependency of any
+    kind between the target and the respective other unit is already
+    in place. Note that this behaviour is disabled if either unit has
+    <varname>DefaultDependencies=no</varname>.</para>
   </refsect1>
 
   <refsect1>
diff --git a/man/systemd.timer.xml b/man/systemd.timer.xml
index c98258a0d7..8cf6c4683b 100644
--- a/man/systemd.timer.xml
+++ b/man/systemd.timer.xml
@@ -1,4 +1,4 @@
-<?xml version='1.0'?> <!--*-nxml-*-->
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
 
@@ -73,19 +73,29 @@
     <filename>foo.timer</filename> activates a matching service
     <filename>foo.service</filename>. The unit to activate may be
     controlled by <varname>Unit=</varname> (see below).</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Timer units automatically gain a <varname>Before=</varname>
+    dependency on the service they are supposed to activate.</para>
 
     <para>Unless <varname>DefaultDependencies=</varname> is set to
     <option>false</option>, all timer units will implicitly have
-    dependencies of type <varname>Conflicts=</varname> and
-    <varname>Before=</varname> on <filename>shutdown.target</filename>
-    to ensure that they are stopped cleanly prior to system shutdown.
-    Timer units with at least one <varname>OnCalendar=</varname>
-    directive will have an additional <varname>After=</varname>
-    dependency on <filename>timer-sync.target</filename> to avoid
-    being started before the system clock has been correctly set. Only
-    timer units involved with early boot or late system shutdown
-    should disable the <varname>DefaultDependencies=</varname>
-    option.</para>
+    dependencies of type <varname>Requires=</varname> and
+    <varname>After=</varname> on <filename>sysinit.target</filename>,
+    a dependency of type <varname>Before=</varname> on
+    <filename>timers.target</filename>, as well as
+    <varname>Conflicts=</varname> and <varname>Before=</varname> on
+    <filename>shutdown.target</filename> to ensure that they are
+    stopped cleanly prior to system shutdown.  Timer units with at
+    least one <varname>OnCalendar=</varname> directive will have an
+    additional <varname>After=</varname> dependency on
+    <filename>timer-sync.target</filename> to avoid being started
+    before the system clock has been correctly set. Only timer units
+    involved with early boot or late system shutdown should disable
+    the <varname>DefaultDependencies=</varname> option.</para>
   </refsect1>
 
   <refsect1>
diff --git a/man/systemd.unit.xml b/man/systemd.unit.xml
index caba7ea69d..b4044f43ef 100644
--- a/man/systemd.unit.xml
+++ b/man/systemd.unit.xml
@@ -1,4 +1,4 @@
-<?xml version='1.0'?> <!--*-nxml-*-->
+<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
 <!ENTITY % entities SYSTEM "custom-entities.ent" >
@@ -195,12 +195,6 @@
          consider it mostly obsolete, and want people to
          use .d/ drop-ins instead. -->
 
-    <para>Note that while systemd offers a flexible dependency system
-    between units it is recommended to use this functionality only
-    sparingly and instead rely on techniques such as bus-based or
-    socket-based activation which make dependencies implicit,
-    resulting in a both simpler and more flexible system.</para>
-
     <para>Some unit names reflect paths existing in the file system
     namespace. Example: a device unit
     <filename>dev-sda.device</filename> refers to a device with the
@@ -254,6 +248,31 @@
   </refsect1>
 
   <refsect1>
+    <title>Automatic Dependencies</title>
+
+    <para>Note that while systemd offers a flexible dependency system
+    between units it is recommended to use this functionality only
+    sparingly and instead rely on techniques such as bus-based or
+    socket-based activation which make dependencies implicit,
+    resulting in a both simpler and more flexible system.</para>
+
+    <para>A number of unit dependencies are automatically established,
+    depending on unit configuration. On top of that, for units with
+    <varname>DefaultDependencies=yes</varname> (the default) a couple
+    of additional dependencies are added. The precise effect of
+    <varname>DefaultDependencies=yes</varname> depends on the unit
+    type (see below).</para>
+
+    <para>If <varname>DefaultDependencies=yes</varname> is set, units
+    that are referenced by other units of type
+    <filename>.target</filename> via a <varname>Wants=</varname> or
+    <varname>Requires=</varname> dependency might automatically gain
+    an <varname>Before=</varname> dependency too. See
+    <citerefentry><refentrytitle>systemd.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+    for details.</para>
+  </refsect1>
+
+  <refsect1>
     <title>Unit File Load Path</title>
 
     <para>Unit files are loaded from a set of paths determined during