Remove check_attach

This patch finishes to remove the 'check_attach' call from Nova
completely. As Cinder already performs the required checks as part
of the 'reserve_volume' (os-reserve) call it is unnecessary to check the
statemachine in Nova also and it can lead to race conditions.

The missing 'reserve_volume' call is added to the BFV flow. In case of
build failure the volume will be locked in 'attaching' state until the
instance in ERROR state is cleaned up.

We also check AZ for each volume attach operation which we haven't
done for unshelve. A release note is added to enable 'cross_az_attach'
in case the user does not care about AZ.

The compute service version had to be bumped as the old computes still
perform 'check_attach', which will fail when the API reserves the
volume and the volume state moves to 'attaching'. If the computes
are not new enough the old check will be called as opposed to
'reserve_volume'.

Closes-Bug: #1581230
Change-Id: I3a3caa4c566ecc132aa2699f8c7e5987bbcc863a

1 files changed, 9 insertions, 12 deletions

diff --git a/nova/virt/block_device.py b/nova/virt/block_device.py
index 1da9d09912..d8c07aea98 100644
--- a/nova/virt/block_device.py
+++ b/nova/virt/block_device.py
@@ -244,10 +244,10 @@ class DriverVolumeBlockDevice(DriverBlockDevice):
 
     @update_db
     def attach(self, context, instance, volume_api, virt_driver,
-               do_check_attach=True, do_driver_attach=False, **kwargs):
+               do_driver_attach=False, **kwargs):
         volume = volume_api.get(context, self.volume_id)
-        if do_check_attach:
-            volume_api.check_attach(context, volume, instance=instance)
+        volume_api.check_availability_zone(context, volume,
+                                           instance=instance)
 
         volume_id = volume['id']
         context = context.elevated()
@@ -367,7 +367,7 @@ class DriverSnapshotBlockDevice(DriverVolumeBlockDevice):
     _proxy_as_attr = set(['volume_size', 'volume_id', 'snapshot_id'])
 
     def attach(self, context, instance, volume_api,
-               virt_driver, wait_func=None, do_check_attach=True):
+               virt_driver, wait_func=None):
 
         if not self.volume_id:
             av_zone = _get_volume_create_az_value(instance)
@@ -382,8 +382,7 @@ class DriverSnapshotBlockDevice(DriverVolumeBlockDevice):
 
         # Call the volume attach now
         super(DriverSnapshotBlockDevice, self).attach(
-            context, instance, volume_api, virt_driver,
-            do_check_attach=do_check_attach)
+            context, instance, volume_api, virt_driver)
 
 
 class DriverImageBlockDevice(DriverVolumeBlockDevice):
@@ -392,7 +391,7 @@ class DriverImageBlockDevice(DriverVolumeBlockDevice):
     _proxy_as_attr = set(['volume_size', 'volume_id', 'image_id'])
 
     def attach(self, context, instance, volume_api,
-               virt_driver, wait_func=None, do_check_attach=True):
+               virt_driver, wait_func=None):
         if not self.volume_id:
             av_zone = _get_volume_create_az_value(instance)
             vol = volume_api.create(context, self.volume_size,
@@ -404,8 +403,7 @@ class DriverImageBlockDevice(DriverVolumeBlockDevice):
             self.volume_id = vol['id']
 
         super(DriverImageBlockDevice, self).attach(
-            context, instance, volume_api, virt_driver,
-            do_check_attach=do_check_attach)
+            context, instance, volume_api, virt_driver)
 
 
 class DriverBlankBlockDevice(DriverVolumeBlockDevice):
@@ -414,7 +412,7 @@ class DriverBlankBlockDevice(DriverVolumeBlockDevice):
     _proxy_as_attr = set(['volume_size', 'volume_id', 'image_id'])
 
     def attach(self, context, instance, volume_api,
-               virt_driver, wait_func=None, do_check_attach=True):
+               virt_driver, wait_func=None):
         if not self.volume_id:
             vol_name = instance.uuid + '-blank-vol'
             av_zone = _get_volume_create_az_value(instance)
@@ -426,8 +424,7 @@ class DriverBlankBlockDevice(DriverVolumeBlockDevice):
             self.volume_id = vol['id']
 
         super(DriverBlankBlockDevice, self).attach(
-            context, instance, volume_api, virt_driver,
-            do_check_attach=do_check_attach)
+            context, instance, volume_api, virt_driver)
 
 
 def _convert_block_devices(device_type, block_device_mapping):