diff --git a/nova/endpoint/cloud.py b/nova/endpoint/cloud.py
index 5c30d6002863..882ce5784a5f 100644
--- a/nova/endpoint/cloud.py
+++ b/nova/endpoint/cloud.py
@@ -320,7 +320,11 @@ class CloudController(object):
 def attach_volume(self, context, volume_id, instance_id, device, **kwargs):
 volume = self._get_volume(context, volume_id)
 if volume['status'] == "attached":
- raise exception.Error("Volume is already attached")
+ raise exception.ApiError("Volume is already attached")
+ # TODO(vish): looping through all volumes is slow. We should probably maintain an index
+ for vol in self.volumes:
+ if vol['instance_id'] == instance_id and vol['mountpoint'] == device:
+ raise exception.ApiError("Volume %s is already attachted to %s" % (vol.volume_id, vol['mountpoint']))
 volume.start_attach(instance_id, device)
 instance = self._get_instance(context, instance_id)
 compute_node = instance['node_name']
</div><div class="naked_ctrl">
<form action="/index.cgi/larger-text" method="get" name="gate">
<p><a href="http://altstyle.alfasado.net">AltStyle</a> によって変換されたページ <a href="https://opendev.org/openstack/nova/commit/9ebd49fa098c8e5fc21244b1bc6254b39d38752f.diff">(-&gt;オリジナル)</a>
/ <label>アドレス: <input type="text" name="naked_post_url" value="https://opendev.org/openstack/nova/commit/9ebd49fa098c8e5fc21244b1bc6254b39d38752f.diff" size="22" /></label> <label>モード: <select name="naked_post_mode">
<option value="default">デフォルト</option>
<option value="speech">音声ブラウザ</option>
<option value="ruby">ルビ付き</option>
<option value="contrast">配色反転</option>
<option value="larger-text" selected="selected">文字拡大</option>
<option value="mobile">モバイル</option>
</select>
<input type="submit" value="表示" />
</p>
</form>
</div>