core: add a "Requires=" dependency between units and the slices they are located in

We place the processes we fork off in the cgroup anyway, and we probably
shouldn't be able to get that far if we couldn't set up the slice due to
resource problems or unmet conditions. Hence upgrade the dependency
between units and the slices they are located in from Wants= to
Requires=.

diff --git a/src/core/unit.c b/src/core/unit.c
index 3a6313e4a28afc270a6bce4a47e92128ef6bef68..30d4e00c9419e11e05d5f926bc046c83897e2ce7 100644 (file)
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -1129,12 +1129,12 @@ static int unit_add_slice_dependencies(Unit *u) {
                 return 0;
 
         if (UNIT_ISSET(u->slice))
-                return unit_add_two_dependencies(u, UNIT_AFTER, UNIT_WANTS, UNIT_DEREF(u->slice), true);
+                return unit_add_two_dependencies(u, UNIT_AFTER, UNIT_REQUIRES, UNIT_DEREF(u->slice), true);
 
-        if (streq(u->id, SPECIAL_ROOT_SLICE))
+        if (unit_has_name(u, SPECIAL_ROOT_SLICE))
                 return 0;
 
-        return unit_add_two_dependencies_by_name(u, UNIT_AFTER, UNIT_WANTS, SPECIAL_ROOT_SLICE, NULL, true);
+        return unit_add_two_dependencies_by_name(u, UNIT_AFTER, UNIT_REQUIRES, SPECIAL_ROOT_SLICE, NULL, true);
 }
 
 static int unit_add_mount_dependencies(Unit *u) {