Add 'detaching' to volume status

Fixes bug #1004382

When attach a volume , the volume status is "available -> attaching ->
in-use", But when detaching a volume , the volume status is "in-use ->
available". So We need 'detaching' volume status, it make the change of
state of the volume more clearly.

Change-Id: I544220c206899307294d50e26679f5351fdc0cd7

nova/compute/api.py

@@ -1842,6 +1842,7 @@ def _detach_volume(self, context, instance, volume_id):
 
         volume = self.volume_api.get(context, volume_id)
         self.volume_api.check_detach(context, volume)
+        self.volume_api.begin_detaching(context, volume)
 
         self.compute_rpcapi.detach_volume(context, instance=instance,
                 volume_id=volume_id)

nova/compute/manager.py

@@ -1970,9 +1970,17 @@ def _detach_volume(self, context, instance, bdm):
         #             but added for completeness in case we ever do.
         if connection_info and 'serial' not in connection_info:
             connection_info['serial'] = volume_id
-        self.driver.detach_volume(connection_info,
-                                  instance['name'],
-                                  mp)
+        try:
+            self.driver.detach_volume(connection_info,
+                                      instance['name'],
+                                      mp)
+        except Exception:  # pylint: disable=W0702
+            with excutils.save_and_reraise_exception():
+                msg = _("Faild to detach volume %(volume_id)s from %(mp)s")
+                LOG.exception(msg % locals(), context=context,
+                              instance=instance)
+                volume = self.volume_api.get(context, volume_id)
+                self.volume_api.roll_detaching(context, volume)
 
     @exception.wrap_exception(notifier=notifier, publisher_id=publisher_id())
     @reverts_task_state

nova/tests/fake_volume.py

@@ -258,3 +258,13 @@ def unreserve_volume(self, context, volume):
         LOG.info('unreserving volume %s', volume['id'])
         volume = self.get(context, volume['id'])
         volume['status'] = 'available'
+
+    def begin_detaching(self, context, volume):
+        LOG.info('beging detaching volume %s', volume['id'])
+        volume = self.get(context, volume['id'])
+        volume['status'] = 'detaching'
+
+    def roll_detaching(self, context, volume):
+        LOG.info('roll detaching volume %s', volume['id'])
+        volume = self.get(context, volume['id'])
+        volume['status'] = 'in-use'

nova/tests/policy.json

@@ -137,6 +137,8 @@
     "volume:detach": [],
     "volume:reserve_volume": [],
     "volume:unreserve_volume": [],
+    "volume:begin_detaching": [],
+    "volume:roll_detaching": [],
     "volume:check_attach": [],
     "volume:check_detach": [],
     "volume:initialize_connection": [],

nova/tests/test_volume.py

@@ -490,6 +490,17 @@ def fake_rollback(context, reservations):
                           'name',
                           'description')
 
+    def test_begin_roll_detaching_volume(self):
+        """Test begin_detaching and roll_detaching functions."""
+        volume = self._create_volume()
+        volume_api = nova.volume.api.API()
+        volume_api.begin_detaching(self.context, volume)
+        volume = db.volume_get(self.context, volume['id'])
+        self.assertEqual(volume['status'], "detaching")
+        volume_api.roll_detaching(self.context, volume)
+        volume = db.volume_get(self.context, volume['id'])
+        self.assertEqual(volume['status'], "in-use")
+
 
 class DriverTestCase(test.TestCase):
     """Base Test class for Drivers."""

nova/volume/api.py

@@ -303,6 +303,17 @@ def unreserve_volume(self, context, volume):
                                   volume['id'],
                                   {"status": "available"})
 
+    @wrap_check_policy
+    def begin_detaching(self, context, volume):
+        self.db.volume_update(context, volume['id'], {"status": "detaching"})
+
+    @wrap_check_policy
+    def roll_detaching(self, context, volume):
+        if volume['status'] == "detaching":
+            self.db.volume_update(context,
+                                  volume['id'],
+                                  {"status": "in-use"})
+
     @wrap_check_policy
     def attach(self, context, volume, instance_uuid, mountpoint):
         host = volume['host']

nova/volume/cinder.py

@@ -165,6 +165,12 @@ def reserve_volume(self, context, volume):
     def unreserve_volume(self, context, volume):
         cinderclient(context).volumes.unreserve(volume['id'])
 
+    def begin_detaching(self, context, volume):
+        cinderclient(context).volumes.begin_detaching(volume['id'])
+
+    def roll_detaching(self, context, volume):
+        cinderclient(context).volumes.roll_detaching(volume['id'])
+
     def attach(self, context, volume, instance_uuid, mountpoint):
         cinderclient(context).volumes.attach(volume['id'],
                                              instance_uuid,