units: introduce remote-fs-setup.target to pull in dependencies from remote mounts

This introduces remote-fs-setup.target independently of
remote-fs-pre.target. The former is only for pulling things in, the
latter only for ordering.

The new semantics:

remote-fs-setup.target: is pulled in automatically by all remote mounts.
Shall be used to pull in other units that want to run when at least one
remote mount is set up. Is not ordered against the actual mount units,
in order to allow activation of its dependencies even 'a posteriori',
i.e. when a mount is established outside of systemd and is only picked
up by it.

remote-fs-pre.target: needs to be pulled in automatically by the
implementing service, is otherwise not part of the initial transaction.
This is ordered before all remote mount units.

A service that wants to be pulled in and run before all remote mounts
should hence have:

a) WantedBy=remote-fs-setup.target -- so that it is pulled in

b) Wants=remote-fs-pre.target + Before=remote-fs-pre.target -- so that
   it is ordered before the mount point, normally.

diff --git a/man/systemd.special.xml b/man/systemd.special.xml
index 8a7242662d7ac6c94958e2266803f05464849b18..18974477ea66b3e1e1085baee533cc2855194e20 100644 (file)
--- a/man/systemd.special.xml
+++ b/man/systemd.special.xml
@@ -79,6 +79,7 @@
                 <filename>reboot.target</filename>,
                 <filename>remote-fs.target</filename>,
                 <filename>remote-fs-pre.target</filename>,
+                <filename>remote-fs-setup.target</filename>,
                 <filename>rescue.target</filename>,
                 <filename>initrd-root-fs.target</filename>,
                 <filename>rpcbind.target</filename>,
@@ -565,11 +566,52 @@
                                 <listitem>
                                         <para>This target unit is
                                         automatically ordered before
-                                        all remote mount points marked
-                                        with <option>auto</option>
+                                        all remote mount point units
                                         (see above). It can be used to
-                                        execute certain units before
-                                        all remote mounts.</para>
+                                        run certain units before the
+                                        remote mounts are
+                                        established. Note that this
+                                        unit is generally not part of
+                                        the initial transaction,
+                                        unless the unit that wants to
+                                        be ordered before all remote
+                                        mounts pulls it in via a
+                                        <varname>Wants=</varname> type
+                                        dependency. If the unit wants
+                                        to be pulled in by the first
+                                        remote mount showing up it
+                                        should use
+                                        <filename>remote-fs-setup.target</filename>
+                                        (see below).</para>
+
+                                        <para>Again, this target unit
+                                        is <emphasis>not</emphasis>
+                                        suitable for pulling in other
+                                        units, it is only useful for
+                                        ordering.</para>
+                                </listitem>
+                        </varlistentry>
+                        <varlistentry>
+                                <term><filename>remote-fs-setup.target</filename></term>
+                                <listitem>
+                                        <para>This target unit is
+                                        automatically pulled in (by a
+                                        <varname>Wants=</varname> type
+                                        dependency) by all remote
+                                        mount points. It can be used
+                                        to run certain units when at
+                                        least one remote file system
+                                        is to be mounted. Note that
+                                        this target is not ordered
+                                        against the remote mounts, use
+                                        <filename>remote-fs-pre.target</filename>
+                                        for that.</para>
+
+                                        <para>Again, this target unit
+                                        is <emphasis>not</emphasis>
+                                        suitable for ordering, it is
+                                        only useful for pulling in
+                                        other units.</para>
                                 </listitem>
                         </varlistentry>
                         <varlistentry>

diff --git a/src/core/mount.c b/src/core/mount.c
index 0adf04e9bf4aaac25c5f256e42a01c9a336f0632..c4074ebd2e6cc04ce416d70bbf1588eee73c7756 100644 (file)
--- a/src/core/mount.c
+++ b/src/core/mount.c
@@ -441,7 +441,7 @@ static int mount_add_quota_links(Mount *m) {
 static int mount_add_default_dependencies(Mount *m) {
         int r;
         MountParameters *p;
-        const char *after;
+        const char *after, *setup;
 
         assert(m);
 
@@ -456,15 +456,24 @@ static int mount_add_default_dependencies(Mount *m) {
         if (path_equal(m->where, "/"))
                 return 0;
 
-        if (mount_is_network(p))
+        if (mount_is_network(p)) {
                 after = SPECIAL_REMOTE_FS_PRE_TARGET;
-        else
+                setup = SPECIAL_REMOTE_FS_SETUP_TARGET;
+        } else {
                 after = SPECIAL_LOCAL_FS_PRE_TARGET;
+                setup = NULL;
+        }
 
-        r = unit_add_two_dependencies_by_name(UNIT(m), UNIT_WANTS, UNIT_AFTER, after, NULL, true);
+        r = unit_add_dependency_by_name(UNIT(m), UNIT_AFTER, after, NULL, true);
         if (r < 0)
                 return r;
 
+        if (setup) {
+                r = unit_add_dependency_by_name(UNIT(m), UNIT_WANTS, setup, NULL, true);
+                if (r < 0)
+                        return r;
+        }
+
         r = unit_add_two_dependencies_by_name(UNIT(m), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_UMOUNT_TARGET, NULL, true);
         if (r < 0)
                 return r;

diff --git a/src/core/special.h b/src/core/special.h
index ad873a9c31f2d98b68ab9c3104c04fb4fd6d9a32..dae7446d73d7b42468099630617a219086790403 100644 (file)
--- a/src/core/special.h
+++ b/src/core/special.h
@@ -54,6 +54,7 @@
 #define SPECIAL_INITRD_ROOT_FS_TARGET "initrd-root-fs.target"
 #define SPECIAL_REMOTE_FS_TARGET "remote-fs.target"       /* LSB's $remote_fs */
 #define SPECIAL_REMOTE_FS_PRE_TARGET "remote-fs-pre.target"
+#define SPECIAL_REMOTE_FS_SETUP_TARGET "remote-fs-setup.target"
 #define SPECIAL_SWAP_TARGET "swap.target"
 #define SPECIAL_BASIC_TARGET "basic.target"
 

diff --git a/src/fstab-generator/fstab-generator.c b/src/fstab-generator/fstab-generator.c
index 9754f3a69a76c9ebd7b511775635189e50ae7d83..2f157c83481fba28742440b2bfaf16233fd5fc54 100644 (file)
--- a/src/fstab-generator/fstab-generator.c
+++ b/src/fstab-generator/fstab-generator.c
@@ -205,9 +205,20 @@ static bool mount_is_rootfs(struct mntent *me) {
         return hasmntopt(me, "x-initrd.rootfs");
 }
 
-static int add_mount(const char *what, const char *where, const char *type, const char *opts,
-                     int passno, bool noauto, bool nofail, bool automount, bool isbind,
-                     const char *pre, const char *post, const char *source) {
+static int add_mount(
+                const char *what,
+                const char *where,
+                const char *type,
+                const char *opts,
+                int passno,
+                bool noauto,
+                bool nofail,
+                bool automount,
+                bool isbind,
+                const char *pre,
+                const char *post,
+                const char *setup,
+                const char *source) {
         char _cleanup_free_
                 *name = NULL, *unit = NULL, *lnk = NULL, *device = NULL,
                 *automount_name = NULL, *automount_unit = NULL;
@@ -259,10 +270,14 @@ static int add_mount(const char *what, const char *where, const char *type, cons
         if (!path_equal(where, "/")) {
                 if (pre)
                         fprintf(f,
-                                "After=%s\n"
-                                "Wants=%s\n",
-                                pre,
+                                "After=%s\n",
                                 pre);
+
+                if (setup)
+                        fprintf(f,
+                                "Wants=%s\n",
+                                setup);
+
                 fprintf(f,
                         "Conflicts=" SPECIAL_UMOUNT_TARGET "\n"
                         "Before=" SPECIAL_UMOUNT_TARGET "\n");
@@ -430,7 +445,7 @@ static int parse_fstab(const char *prefix, bool initrd) {
                         k = add_swap(what, me);
                 else {
                         bool noauto, nofail, automount, isbind;
-                        const char *pre, *post;
+                        const char *pre, *post, *setup;
 
                         noauto = !!hasmntopt(me, "noauto");
                         nofail = !!hasmntopt(me, "nofail");
@@ -442,20 +457,24 @@ static int parse_fstab(const char *prefix, bool initrd) {
                         if (initrd) {
                                 post = SPECIAL_INITRD_FS_TARGET;
                                 pre = NULL;
+                                setup = NULL;
                         } else if (mount_is_rootfs(me)) {
                                 post = SPECIAL_INITRD_ROOT_FS_TARGET;
                                 pre = NULL;
+                                setup = NULL;
                         } else if (mount_is_network(me)) {
                                 post = SPECIAL_REMOTE_FS_TARGET;
                                 pre = SPECIAL_REMOTE_FS_PRE_TARGET;
+                                setup = SPECIAL_REMOTE_FS_SETUP_TARGET;
                         } else {
                                 post = SPECIAL_LOCAL_FS_TARGET;
                                 pre = SPECIAL_LOCAL_FS_PRE_TARGET;
+                                setup = NULL;
                         }
 
                         k = add_mount(what, where, me->mnt_type, me->mnt_opts,
-                                     me->mnt_passno, noauto, nofail, automount,
-                                     isbind, pre, post, fstab_path);
+                                      me->mnt_passno, noauto, nofail, automount,
+                                      isbind, pre, post, setup, fstab_path);
                 }
 
                 if (k < 0)
@@ -539,7 +558,7 @@ static int parse_new_root_from_proc_cmdline(void) {
 
         log_debug("Found entry what=%s where=/sysroot type=%s", what, type);
         r = add_mount(what, "/sysroot", type, opts, 0, false, false, false,
-                      false, NULL, SPECIAL_INITRD_ROOT_FS_TARGET, "/proc/cmdline");
+                      false, NULL, SPECIAL_INITRD_ROOT_FS_TARGET, NULL, "/proc/cmdline");
 
         return (r < 0) ? r : 0;
 }

diff --git a/units/local-fs.target b/units/local-fs.target
index dd92b17b6abcd13c5f13aa4b08fecc8ea6dea41c..ee02e4e98861c21fec163ba9b9dbc9eec80172bf 100644 (file)
--- a/units/local-fs.target
+++ b/units/local-fs.target
@@ -8,5 +8,6 @@
 [Unit]
 Description=Local File Systems
 Documentation=man:systemd.special(7)
+After=local-fs-pre.target
 OnFailure=emergency.target
 OnFailureIsolate=yes

diff --git a/units/remote-fs-setup.target b/units/remote-fs-setup.target
new file mode 100644 (file)
index 0000000..8043717
--- /dev/null
+++ b/units/remote-fs-setup.target
@@ -0,0 +1,11 @@
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+[Unit]
+Description=Remote File System Setup
+Documentation=man:systemd.special(7)
+DefaultDependencies=no

diff --git a/units/remote-fs.target b/units/remote-fs.target
index 9e68878ad8d2c1a949acf8b8a4b214da8bc57877..e867b8d997964839d9ec6aca5e73d0c6319507fd 100644 (file)
--- a/units/remote-fs.target
+++ b/units/remote-fs.target
@@ -8,6 +8,7 @@
 [Unit]
 Description=Remote File Systems
 Documentation=man:systemd.special(7)
+After=remote-fs-pre.target remote-fs-setup.target
 
 [Install]
 WantedBy=multi-user.target