From a4305884e529705f5edd98a7f0c13cdd1d472cbc Mon Sep 17 00:00:00 2001
From: Gerald McBrearty <gfm@us.ibm.com>
Date: Fri, 14 Apr 2017 10:10:23 -0500
Subject: [PATCH] attach_volume first check for existing attachment

Attach_volume has logic to check for an existing
attachment and return that attachment. Moved this
logic before checking to see if the status of the
volume is 'is-use'.

If a first call to attach fails with a time out,
cinderclient will retry the operation therefore
attach_volume needs to return the already existing
attachment if it exists for this instance.

Updated testcase.

Change-Id: I86d7f01b6aca376f9d8cf9de6cdfecd436726a0e
Closes-bug: 1681543
---
 cinder/tests/unit/volume/test_connection.py |  6 ++++++
 cinder/volume/manager.py                    | 10 +++++-----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/cinder/tests/unit/volume/test_connection.py b/cinder/tests/unit/volume/test_connection.py
index 7465f1bb4..f6ca70289 100644
--- a/cinder/tests/unit/volume/test_connection.py
+++ b/cinder/tests/unit/volume/test_connection.py
@@ -220,6 +220,12 @@ class VolumeAttachDetachTestCase(base.BaseVolumeTestCase):
                                                instance_uuid, None,
                                                mountpoint, 'ro',
                                                volume=volume_passed)
+        attachment2 = self.volume.attach_volume(self.user_context,
+                                                volume_id,
+                                                instance_uuid, None,
+                                                mountpoint, 'ro',
+                                                volume=volume_passed)
+        self.assertEqual(attachment.id, attachment2.id)
         vol = objects.Volume.get_by_id(self.context, volume_id)
         self.assertEqual("in-use", vol.status)
         self.assertEqual(fields.VolumeAttachStatus.ATTACHED,
diff --git a/cinder/volume/manager.py b/cinder/volume/manager.py
index a856c44e3..67dcc268d 100644
--- a/cinder/volume/manager.py
+++ b/cinder/volume/manager.py
@@ -1005,11 +1005,6 @@ class VolumeManager(manager.CleanableManager,
                 raise exception.InvalidVolume(
                     reason=_("being attached by different mode"))
 
-        if (volume.status == 'in-use' and not volume.multiattach
-           and not volume.migration_status):
-            raise exception.InvalidVolume(
-                reason=_("volume is already attached"))
-
         host_name_sanitized = utils.sanitize_hostname(
             host_name) if host_name else None
         if instance_uuid:
@@ -1028,6 +1023,11 @@ class VolumeManager(manager.CleanableManager,
                     volume.save()
                     return attachment
 
+        if (volume.status == 'in-use' and not volume.multiattach
+           and not volume.migration_status):
+            raise exception.InvalidVolume(
+                reason=_("volume is already attached"))
+
         self._notify_about_volume_usage(context, volume,
                                         "attach.start")