diff --git a/src/lib/Hydra/Controller/Admin.pm b/src/lib/Hydra/Controller/Admin.pm
index f2a34459..a73762dc 100644
--- a/src/lib/Hydra/Controller/Admin.pm
+++ b/src/lib/Hydra/Controller/Admin.pm
@@ -34,12 +34,12 @@ sub machines : Chained('admin') PathPart('machines') Args(0) {
 
 sub clear_queue_non_current : Chained('admin') PathPart('clear-queue-non-current') Args(0) {
     my ($self, $c) = @_;
-    my $time = time();
-    $c->model('DB::Builds')->search(
+    my $builds = $c->model('DB::Builds')->search(
         { finished => 0, busy => 0
         , id => { -not_in => \ "select build from JobsetEvalMembers where eval in (select max(id) from JobsetEvals where hasNewBuilds = 1 group by project, jobset)" }
-        }, {})
-        ->update({ finished => 1, buildstatus => 4, starttime => $time, stoptime => $time });
+        });
+    my $n = cancelBuilds($c->model('DB')->schema, $builds);
+    $c->flash->{successMsg} = "$n builds have been cancelled.";
     $c->res->redirect($c->request->referer // "/admin");
 }
 
diff --git a/src/lib/Hydra/Controller/Build.pm b/src/lib/Hydra/Controller/Build.pm
index f0524aa4..7d62ebba 100644
--- a/src/lib/Hydra/Controller/Build.pm
+++ b/src/lib/Hydra/Controller/Build.pm
@@ -60,7 +60,6 @@ sub build_GET {
     $c->stash->{template} = 'build.tt';
     $c->stash->{available} = all { isValidPath($_->path) } $build->buildoutputs->all;
     $c->stash->{drvAvailable} = isValidPath $build->drvpath;
-    $c->stash->{flashMsg} = $c->flash->{buildMsg};
 
     if (!$build->finished && $build->busy) {
         $c->stash->{logtext} = read_file($build->logfile, err_mode => 'quiet') // "";
@@ -448,7 +447,7 @@ sub restart : Chained('buildChain') PathPart Args(0) {
 
     restartBuild($c->model('DB')->schema, $build);
 
-    $c->flash->{buildMsg} = "Build has been restarted.";
+    $c->flash->{successMsg} = "Build has been restarted.";
 
     $c->res->redirect($c->uri_for($self->action_for("build"), $c->req->captures));
 }
@@ -456,30 +455,11 @@ sub restart : Chained('buildChain') PathPart Args(0) {
 
 sub cancel : Chained('buildChain') PathPart Args(0) {
     my ($self, $c) = @_;
-
     my $build = $c->stash->{build};
-
     requireProjectOwner($c, $build->project);
-
-    txn_do($c->model('DB')->schema, sub {
-        error($c, "This build cannot be cancelled.")
-            if $build->finished || $build->busy;
-
-        # !!! Actually, it would be nice to be able to cancel busy
-        # builds as well, but we would have to send a signal or
-        # something to the build process.
-
-        my $time = time();
-        $build->update(
-            { finished => 1, busy => 0
-            , iscachedbuild => 0, buildstatus => 4 # = cancelled
-            , starttime => $time
-            , stoptime => $time
-            });
-    });
-
-    $c->flash->{buildMsg} = "Build has been cancelled.";
-
+    my $n = cancelBuilds($c->model('DB')->schema, $c->model('DB::Builds')->search({ id => $build->id }));
+    error($c, "This build cannot be cancelled.") if $n != 1;
+    $c->flash->{successMsg} = "Build has been cancelled.";
     $c->res->redirect($c->uri_for($self->action_for("build"), $c->req->captures));
 }
 
@@ -500,7 +480,7 @@ sub keep : Chained('buildChain') PathPart Args(1) {
         $build->update({keep => $keep});
     });
 
-    $c->flash->{buildMsg} =
+    $c->flash->{successMsg} =
         $keep ? "Build will be kept." : "Build will not be kept.";
 
     $c->res->redirect($c->uri_for($self->action_for("build"), $c->req->captures));
@@ -530,7 +510,7 @@ sub add_to_release : Chained('buildChain') PathPart('add-to-release') Args(0) {
 
     $release->releasemembers->create({build => $build->id, description => $build->description});
 
-    $c->flash->{buildMsg} = "Build added to project <tt>$releaseName</tt>.";
+    $c->flash->{successMsg} = "Build added to project <tt>$releaseName</tt>.";
 
     $c->res->redirect($c->uri_for($self->action_for("build"), $c->req->captures));
 }
@@ -607,7 +587,7 @@ sub clone_submit : Chained('buildChain') PathPart('clone/submit') Args(0) {
 
     error($c, "This build has already been performed.") unless $newBuild;
 
-    $c->flash->{buildMsg} = "Build " . $newBuild->id . " added to the queue.";
+    $c->flash->{successMsg} = "Build " . $newBuild->id . " added to the queue.";
 
     $c->res->redirect($c->uri_for($c->controller('Root')->action_for('queue')));
 }
diff --git a/src/lib/Hydra/Controller/JobsetEval.pm b/src/lib/Hydra/Controller/JobsetEval.pm
index 9fa99dd8..b3291166 100644
--- a/src/lib/Hydra/Controller/JobsetEval.pm
+++ b/src/lib/Hydra/Controller/JobsetEval.pm
@@ -152,6 +152,15 @@ sub release : Chained('eval') PathPart('release') Args(0) {
 }
 
 
+sub cancel : Chained('eval') PathPart('cancel') Args(0) {
+    my ($self, $c) = @_;
+    requireProjectOwner($c, $c->stash->{eval}->project);
+    my $n = cancelBuilds($c->model('DB')->schema, $c->stash->{eval}->builds);
+    $c->flash->{successMsg} = "$n builds have been cancelled.";
+    $c->res->redirect($c->uri_for($c->controller('JobsetEval')->action_for('view'), $c->req->captures));
+}
+
+
 # Hydra::Base::Controller::NixChannel needs this.
 sub nix : Chained('eval') PathPart('channel') CaptureArgs(0) {
     my ($self, $c) = @_;
diff --git a/src/lib/Hydra/Helper/Nix.pm b/src/lib/Hydra/Helper/Nix.pm
index d12c569c..f5d62c7a 100644
--- a/src/lib/Hydra/Helper/Nix.pm
+++ b/src/lib/Hydra/Helper/Nix.pm
@@ -21,7 +21,8 @@ our @EXPORT = qw(
     getEvals getMachines
     pathIsInsidePrefix
     captureStdoutStderr run grab
-    getTotalShares);
+    getTotalShares
+    cancelBuilds);
 
 
 sub getHydraHome {
@@ -43,11 +44,12 @@ sub getHydraConfig {
 # doesn't work.
 sub txn_do {
     my ($db, $coderef) = @_;
+    my $res;
     while (1) {
         eval {
-            $db->txn_do($coderef);
+            $res = $db->txn_do($coderef);
         };
-        last if !$@;
+        return $res if !$@;
         die $@ unless $@ =~ "database is locked";
     }
 }
@@ -542,4 +544,21 @@ sub getTotalShares {
 }
 
 
+sub cancelBuilds($$) {
+    my ($db, $builds) = @_;
+    return txn_do($db, sub {
+        $builds = $builds->search({ finished => 0, busy => 0 });
+        my $n = $builds->count;
+        my $time = time();
+        $builds->update(
+            { finished => 1,
+            , iscachedbuild => 0, buildstatus => 4 # = cancelled
+            , starttime => $time
+            , stoptime => $time
+            });
+        return $n;
+    });
+}
+
+
 1;
diff --git a/src/root/jobset-eval.tt b/src/root/jobset-eval.tt
index e6d579ef..81044b0a 100644
--- a/src/root/jobset-eval.tt
+++ b/src/root/jobset-eval.tt
@@ -42,6 +42,7 @@ c.uri_for(c.controller('JobsetEval').action_for('view'),
       </a>
       <ul class="dropdown-menu">
         <li><a href="[% c.uri_for(c.controller('JobsetEval').action_for('release'), [eval.id]) %]">Create a release from this evaluation</a></li>
+        <li><a href="[% c.uri_for(c.controller('JobsetEval').action_for('cancel'), [eval.id]) %]">Cancel all scheduled builds</a></li>
       </ul>
     </li>
   [% END %]
diff --git a/src/root/topbar.tt b/src/root/topbar.tt
index af539ffa..f3a8a89d 100644
--- a/src/root/topbar.tt
+++ b/src/root/topbar.tt
@@ -91,7 +91,7 @@
         class = "" %]
       [% INCLUDE menuItem
         uri = c.uri_for(c.controller('Admin').action_for('clear_queue_non_current'))
-        title = "Clear all non-running old builds from queue"
+        title = "Clear scheduled non-current builds from queue"
         confirmmsg = "Are you sure you want to clear the queue?"
         class = "" %]
       [% INCLUDE menuItem