diff --git a/lib/vasync.js b/lib/vasync.js
index 00bfdbc..fe6f501 100644
--- a/lib/vasync.js
+++ b/lib/vasync.js
@@ -434,6 +434,7 @@ function Barrier(args)
 		this.recent = [];
 	}
 
+	this.aborted = {};
 	this.pending = {};
 	this.scheduled = false;
 }
@@ -444,14 +445,22 @@ Barrier.prototype.start = function (name)
 {
 	mod_assert.ok(!this.pending.hasOwnProperty(name),
 	    'operation "' + name + '" is already pending');
+
+	if (this.aborted.hasOwnProperty(name))
+		delete this.aborted[name];
+
 	this.pending[name] = Date.now();
 };
 
 Barrier.prototype.done = function (name)
 {
-	mod_assert.ok(this.pending.hasOwnProperty(name),
+	mod_assert.ok(this.pending.hasOwnProperty(name) ||
+	    this.aborted.hasOwnProperty(name),
 	    'operation "' + name + '" is not pending');
 
+	if (this.aborted.hasOwnProperty(name))
+		return;
+
 	if (this.recent) {
 		this.recent.push({
 		    'name': name,
@@ -494,3 +503,20 @@ Barrier.prototype.done = function (name)
 			self.emit('drain');
 	});
 };
+
+Barrier.prototype.abort = function (err)
+{
+	var self = this;
+
+	var now = Date.now();
+	Object.keys(this.pending).forEach(function (name) {
+		self.aborted[name] = now;
+	});
+	this.pending = {};
+	this.scheduled = true;
+
+	setImmediate(function () {
+		self.scheduled = false;
+		self.emit('drain', err);
+	});
+};