Implemented x-systemd.{required,wanted}-by= options

Teaches systemd-fstab-generator these two unit options,
creating appropriate dependencies on the generated .mount
units.  When used, they override any other automatically
generated dependencies, such as local-fs.target, and are
NOT suppressed by noauto.  The new options are ignored for
/, in the same way that noauto is ignored.

Fixes: #14380
Signed-off-by: Antonio Russo <antonio.e.russo@gmail.com>

diff --git a/man/systemd.mount.xml b/man/systemd.mount.xml
index 6ee9d47db20ea052d20ad8724c1dd1f742727db1..d775d74053fdf14180a05453f3d8381ce8e6c7b8 100644 (file)
--- a/man/systemd.mount.xml
+++ b/man/systemd.mount.xml
@@ -226,6 +226,21 @@
         for details.</para></listitem>
       </varlistentry>
 
+      <varlistentry>
+        <term><option>x-systemd.wanted-by=</option></term>
+        <term><option>x-systemd.required-by=</option></term>
+
+        <listitem><para>In the created mount unit, configures a
+        <varname>WantedBy=</varname> or <varname>RequiredBy=</varname>
+        dependency on another unit.  This option may be
+        specified more than once. If this is specified, the normal
+        automatic dependencies on the created mount unit, e.g.,
+        <filename>local-fs.target</filename>, are not automatically
+        created. See <varname>WantedBy=</varname> and <varname>RequiredBy=</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>
 

diff --git a/src/fstab-generator/fstab-generator.c b/src/fstab-generator/fstab-generator.c
index 6fd6fbdf1ccdf542b8cf6ae6b7ac3a16d36ff723..e0f1076326f2d7d3b1a926dac13a502cb91bceaa 100644 (file)
--- a/src/fstab-generator/fstab-generator.c
+++ b/src/fstab-generator/fstab-generator.c
@@ -306,6 +306,7 @@ static int add_mount(
                 *automount_name = NULL,
                 *filtered = NULL,
                 *where_escaped = NULL;
+        _cleanup_strv_free_ char **wanted_by = NULL, **required_by = NULL;
         _cleanup_fclose_ FILE *f = NULL;
         int r;
 
@@ -327,6 +328,14 @@ static int add_mount(
             mount_point_ignore(where))
                 return 0;
 
+        r = fstab_extract_values(opts, "x-systemd.wanted-by", &wanted_by);
+        if (r < 0)
+                return r;
+
+        r = fstab_extract_values(opts, "x-systemd.required-by", &required_by);
+        if (r < 0)
+                return r;
+
         if (path_equal(where, "/")) {
                 if (flags & NOAUTO)
                         log_warning("Ignoring \"noauto\" for root device");
@@ -334,7 +343,13 @@ static int add_mount(
                         log_warning("Ignoring \"nofail\" for root device");
                 if (flags & AUTOMOUNT)
                         log_warning("Ignoring automount option for root device");
+                if (!strv_isempty(wanted_by))
+                        log_warning("Ignoring \"x-systemd.wanted-by=\" for root device");
+                if (!strv_isempty(required_by))
+                        log_warning("Ignoring \"x-systemd.required-by=\" for root device");
 
+                required_by = strv_free(required_by);
+                wanted_by = strv_free(wanted_by);
                 SET_FLAG(flags, NOAUTO | NOFAIL | AUTOMOUNT, false);
         }
 
@@ -451,14 +466,28 @@ static int add_mount(
                         return r;
         }
 
-        if (!(flags & NOAUTO) && !(flags & AUTOMOUNT)) {
-                r = generator_add_symlink(dest, post,
-                                          (flags & NOFAIL) ? "wants" : "requires", name);
-                if (r < 0)
-                        return r;
-        }
-
-        if (flags & AUTOMOUNT) {
+        if (!FLAGS_SET(flags, AUTOMOUNT)) {
+                if (!FLAGS_SET(flags, NOAUTO) && strv_isempty(wanted_by) && strv_isempty(required_by)) {
+                        r = generator_add_symlink(dest, post,
+                                                  (flags & NOFAIL) ? "wants" : "requires", name);
+                        if (r < 0)
+                                return r;
+                } else {
+                        char **s;
+
+                        STRV_FOREACH(s, wanted_by) {
+                                r = generator_add_symlink(dest, *s, "wants", name);
+                                if (r < 0)
+                                        return r;
+                        }
+
+                        STRV_FOREACH(s, required_by) {
+                                r = generator_add_symlink(dest, *s, "requires", name);
+                                if (r < 0)
+                                        return r;
+                        }
+                }
+        } else {
                 r = unit_name_from_path(where, ".automount", &automount_name);
                 if (r < 0)
                         return log_error_errno(r, "Failed to generate unit name: %m");