diff --git a/userspace/marsadm b/userspace/marsadm
index 5cc6164e..a0469e36 100755
--- a/userspace/marsadm
+++ b/userspace/marsadm
@@ -581,46 +581,49 @@ sub _get_prev_pos {
 }
 
 sub _get_common_ancestor {
-  # TODO: recursive formulation, improve efficiency
-  my ($basedir, $pos1, $host1, $dep1, $pos2, $host2, $dep2) = @_;
-  my ($p1, $nr1, $from1, $len1) = _parse_pos($pos1, 0);
-  my ($p2, $nr2, $from2, $len2) = _parse_pos($pos2, 0);
-  if ($p1 eq $p2) {
-    # usually no split brain here (only if both path depths are non-zero)
-    my $split = ($dep1 && $dep2);
-    if (!$split) { # additionally check the corresponding version links
-      my $path1 = sprintf("$basedir/version-%09d-$from1", $nr1);
-      my $path2 = sprintf("$basedir/version-%09d-$from2", $nr2);
-      if (my $vers1 = get_link($path1) and my $vers2 = get_link($path2)) {
-	$split = 1 if $vers1 ne $vers2;
+  for (;;) {
+    my ($basedir, $pos1, $host1, $dep1, $pos2, $host2, $dep2) = @_;
+    my ($p1, $nr1, $from1, $len1) = _parse_pos($pos1, 0);
+    my ($p2, $nr2, $from2, $len2) = _parse_pos($pos2, 0);
+    if ($p1 eq $p2) {
+      # usually no split brain here (only if both path depths are non-zero)
+      my $split = ($dep1 && $dep2);
+      if (!$split) { # additionally check the corresponding version links
+	my $path1 = sprintf("$basedir/version-%09d-$from1", $nr1);
+	my $path2 = sprintf("$basedir/version-%09d-$from2", $nr2);
+	if (my $vers1 = get_link($path1) and my $vers2 = get_link($path2)) {
+	  $split = 1 if $vers1 ne $vers2;
+	}
       }
+      return ($p1, $split);
+    } elsif ($nr1 > $nr2) {
+      # just flip arguments
+      @_ = ($basedir, $pos2, $host2, $dep2, $pos1, $host1, $dep1);
+      next;
+    } elsif ($nr1 < $nr2) {
+      # recursively advance path depth
+      my $vers2 = _get_prev_pos($basedir, $nr2, $host2);
+      return ("", -1) if !$vers2;
+      @_ = ($basedir, $pos1, $host1, $dep1, $vers2, $host2, $dep2 + 1);
+      next;
+    } elsif ($from1 ne $from2) {
+      # split brain is sure now, but continue computing the common split point
+      my $vers1 = _get_prev_pos($basedir, $nr1, $host1);
+      return ("", 1) if !$vers1;
+      my $vers2 = _get_prev_pos($basedir, $nr2, $host2);
+      return ("", 1) if !$vers2;
+      my ($res, $split) = _get_common_ancestor($basedir, $vers1, $host1, $dep1 + 1, $vers2, $host2, $dep2 + 1);
+      return ($res, 1);
+    } elsif ($len1 < $len2) {
+      # there may be no split brain (just incomplete replay) depending on path depth
+      return ($p1, $dep1);
+    } elsif ($len2 < $len1) {
+      # dto symmetric
+      return ($p2, $dep2);
     }
-    return ($p1, $split);
-  } elsif ($nr1 > $nr2) {
-    # just flip arguments
-    return _get_common_ancestor($basedir, $pos2, $host2, $dep2, $pos1, $host1, $dep1);
-  } elsif ($nr1 < $nr2) {
-    # recursively advance path depth
-    my $vers2 = _get_prev_pos($basedir, $nr2, $host2);
-    return ("", -1) if !$vers2;
-    return _get_common_ancestor($basedir, $pos1, $host1, $dep1, $vers2, $host2, $dep2 + 1);
-  } elsif ($from1 ne $from2) {
-    # split brain is sure now, but continue computing the common split point
-    my $vers1 = _get_prev_pos($basedir, $nr1, $host1);
-    return ("", 1) if !$vers1;
-    my $vers2 = _get_prev_pos($basedir, $nr2, $host2);
-    return ("", 1) if !$vers2;
-    my ($res, $split) = _get_common_ancestor($basedir, $vers1, $host1, $dep1 + 1, $vers2, $host2, $dep2 + 1);
-    return ($res, 1);
-  } elsif ($len1 < $len2) {
-    # there may be no split brain (just incomplete replay) depending on path depth
-    return ($p1, $dep1);
-  } elsif ($len2 < $len1) {
-    # dto symmetric
-    return ($p2, $dep2);
+    lwarn "error in algorithm: $p1, $nr1, $from1, $len1 : $p2, $nr2, $from2, $len2\n";
+    return ("", -1);
   }
-  lwarn "error in algorithm: $p1, $nr1, $from1, $len1 : $p2, $nr2, $from2, $len2\n";
-  return ("", -1);
 }
 
 sub get_common_ancestor {