marsadm: fix race between fetch and primary --force

userspace/marsadm

@@ -3941,6 +3941,13 @@ sub primary_phase0 {
   lprint "all preconditions OK for resource '$res'\n";
 }
 
+# only for primary --force: wait until fetch has actually stopped
+sub primary_phase0a {
+  my ($cmd, $res) = @_;
+  return unless $force;
+  wait_cond($cmd, $res, "is-fetch-off");
+}
+
 # only for systemd: wait that primary device is no longer open
 sub primary_phase0b {
   my ($cmd, $res) = @_;
@@ -6762,6 +6769,8 @@ my %cmd_table =
        \&primary_phase0,
        "check preconditions",
        "FORK",
+       \&primary_phase0a,
+       "conditionally wait for fetch off",
        \&primary_phase0b,
        "wait for systemd",
        \&primary_phase1,