diff --git a/lib/EioHandle.php b/lib/EioHandle.php
index 0918ac0..e0bb233 100644
--- a/lib/EioHandle.php
+++ b/lib/EioHandle.php
@@ -10,16 +10,36 @@ use Amp\Success;
 use function Amp\call;
 
 class EioHandle implements Handle {
+    /** @var \Amp\File\Internal\EioPoll */
     private $poll;
+
+    /** @var resource eio file handle. */
     private $fh;
+
+    /** @var string */
     private $path;
+
+    /** @var string */
     private $mode;
+
+    /** @var int */
     private $size;
+
+    /** @var int */
     private $position;
+
+    /** @var \SplQueue */
     private $queue;
+
+    /** @var bool */
     private $isActive = false;
+
+    /** @var bool */
     private $writable = true;
 
+    /** @var \Amp\Promise|null */
+    private $closing;
+
     public function __construct(Internal\EioPoll $poll, $fh, string $path, string $mode, int $size) {
         $this->poll = $poll;
         $this->fh = $fh;
@@ -169,8 +189,12 @@ class EioHandle implements Handle {
      * {@inheritdoc}
      */
     public function close(): Promise {
+        if ($this->closing) {
+            return $this->closing;
+        }
+
         $deferred = new Deferred;
-        $this->poll->listen($deferred->promise());
+        $this->poll->listen($this->closing = $deferred->promise());
 
         \eio_close($this->fh, \EIO_PRI_DEFAULT, [$this, "onClose"], $deferred);
 
diff --git a/lib/Internal/FileTask.php b/lib/Internal/FileTask.php
index cb9f7a3..4e585e5 100644
--- a/lib/Internal/FileTask.php
+++ b/lib/Internal/FileTask.php
@@ -112,7 +112,7 @@ class FileTask extends BlockingDriver implements Task {
                 case "fclose":
                     $file->close();
                     $environment->delete($this->id);
-                    return true;
+                    return;
 
                 default:
                     throw new \Error('Invalid operation');
diff --git a/lib/ParallelHandle.php b/lib/ParallelHandle.php
index 64a06a9..82d3b98 100644
--- a/lib/ParallelHandle.php
+++ b/lib/ParallelHandle.php
@@ -40,6 +40,9 @@ class ParallelHandle implements Handle {
     /** @var bool */
     private $writable = true;
 
+    /** @var \Amp\Promise|null */
+    private $closing;
+
     /**
      * @param \Amp\Parallel\Worker\Worker $worker
      * @param int $id
@@ -73,20 +76,20 @@ class ParallelHandle implements Handle {
      * {@inheritdoc}
      */
     public function close(): Promise {
-        if (!$this->writable) {
-            return new Success;
+        if ($this->closing) {
+            return $this->closing;
         }
 
         $this->writable = false;
 
         if ($this->worker->isRunning()) {
-            $promise = $this->worker->enqueue(new Internal\FileTask('fclose', [], $this->id));
+            $this->closing = $this->worker->enqueue(new Internal\FileTask('fclose', [], $this->id));
             $this->id = null;
-            return $promise;
+        } else {
+            $this->closing = new Success;
         }
 
-        // FIXME: Should that really return new Success instead of an exception?
-        return new Success;
+        return $this->closing;
     }
 
     /**
diff --git a/lib/UvHandle.php b/lib/UvHandle.php
index ffbf23d..14bae6c 100644
--- a/lib/UvHandle.php
+++ b/lib/UvHandle.php
@@ -12,18 +12,39 @@ use Amp\Success;
 use function Amp\call;
 
 class UvHandle implements Handle {
+    /** @var UvPoll */
     private $poll;
-    private $driver;
-    private $fh;
-    private $path;
-    private $mode;
-    private $size;
+
+    /** @var \UVLoop */
     private $loop;
+
+    /** @var resource */
+    private $fh;
+
+    /** @var string */
+    private $path;
+
+    /** @var string */
+    private $mode;
+
+    /** @var int */
+    private $size;
+
+    /** @var int */
     private $position;
+
+    /** @var \SplQueue */
     private $queue;
+
+    /** @var bool */
     private $isActive = false;
+
+    /** @var bool */
     private $writable = true;
 
+    /** @var \Amp\Promise|null */
+    private $closing;
+
     /**
      * @param \Amp\Loop\UvDriver $driver
      * @param UvPoll $poll Poll for keeping the loop active.
@@ -33,7 +54,6 @@ class UvHandle implements Handle {
      * @param int $size
      */
     public function __construct(Loop\UvDriver $driver, UvPoll $poll, $fh, string $path, string $mode, int $size) {
-        $this->driver = $driver;
         $this->poll = $poll;
         $this->fh = $fh;
         $this->path = $path;
@@ -219,8 +239,12 @@ class UvHandle implements Handle {
      * {@inheritdoc}
      */
     public function close(): Promise {
+        if ($this->closing) {
+            return $this->closing;
+        }
+
         $deferred = new Deferred;
-        $this->poll->listen($deferred->promise());
+        $this->poll->listen($this->closing = $deferred->promise());
 
         \uv_fs_close($this->loop, $this->fh, function ($fh) use ($deferred) {
             // FIXME: Check for errors