Handle quota exceed exception

This patch solves two problems:

1. Code duplication about handling quota exceed exceptions.

2. When extending a volume, if OverQuota is caught, Cinder
raised VolumeSizeExceedsAvailableQuota with data from
quota gigabytes. This is not correct, as it may exceed
gigabytes of volume type.

This patch is to transfer quota data from gigabytes or
[volume_type_name]gigabytes to VolumeSizeExceedsAvailableQuota.

3. Raise new exception if overs are not expected.

Change-Id: I811ce51a4aefe8a99f0f5197ab071212322c584d
Closes-bug: 1546890

cinder/tests/unit/test_quota_utils.py

@@ -165,3 +165,80 @@ class QuotaUtilsTest(test.TestCase):
         self.assertRaises(exception.CinderException,
                           quota_utils.validate_setup_for_nested_quota_use,
                           self.context, [], None)
+
+    def _process_reserve_over_quota(self, overs, usages, quotas,
+                                    expected_ex,
+                                    resource='volumes'):
+        ctxt = context.get_admin_context()
+        ctxt.project_id = 'fake'
+        size = 1
+        kwargs = {'overs': overs,
+                  'usages': usages,
+                  'quotas': quotas}
+        exc = exception.OverQuota(**kwargs)
+
+        self.assertRaises(expected_ex,
+                          quota_utils.process_reserve_over_quota,
+                          ctxt, exc,
+                          resource=resource,
+                          size=size)
+
+    def test_volume_size_exceed_quota(self):
+        overs = ['gigabytes']
+        usages = {'gigabytes': {'reserved': 1, 'in_use': 9}}
+        quotas = {'gigabytes': 10, 'snapshots': 10}
+        self._process_reserve_over_quota(
+            overs, usages, quotas,
+            exception.VolumeSizeExceedsAvailableQuota)
+
+    def test_snapshot_limit_exceed_quota(self):
+        overs = ['snapshots']
+        usages = {'snapshots': {'reserved': 1, 'in_use': 9}}
+        quotas = {'gigabytes': 10, 'snapshots': 10}
+        self._process_reserve_over_quota(
+            overs, usages, quotas,
+            exception.SnapshotLimitExceeded,
+            resource='snapshots')
+
+    def test_backup_gigabytes_exceed_quota(self):
+        overs = ['backup_gigabytes']
+        usages = {'backup_gigabytes': {'reserved': 1, 'in_use': 9}}
+        quotas = {'backup_gigabytes': 10}
+        self._process_reserve_over_quota(
+            overs, usages, quotas,
+            exception.VolumeBackupSizeExceedsAvailableQuota,
+            resource='backups')
+
+    def test_backup_limit_quota(self):
+        overs = ['backups']
+        usages = {'backups': {'reserved': 1, 'in_use': 9}}
+        quotas = {'backups': 9}
+        self._process_reserve_over_quota(
+            overs, usages, quotas,
+            exception.BackupLimitExceeded,
+            resource='backups')
+
+    def test_volumes_limit_quota(self):
+        overs = ['volumes']
+        usages = {'volumes': {'reserved': 1, 'in_use': 9}}
+        quotas = {'volumes': 9}
+        self._process_reserve_over_quota(
+            overs, usages, quotas,
+            exception.VolumeLimitExceeded)
+
+    def test_unknown_quota(self):
+        overs = ['unknown']
+        usages = {'volumes': {'reserved': 1, 'in_use': 9}}
+        quotas = {'volumes': 9}
+        self._process_reserve_over_quota(
+            overs, usages, quotas,
+            exception.UnexpectedOverQuota)
+
+    def test_unknown_quota2(self):
+        overs = ['volumes']
+        usages = {'volumes': {'reserved': 1, 'in_use': 9}}
+        quotas = {'volumes': 9}
+        self._process_reserve_over_quota(
+            overs, usages, quotas,
+            exception.UnexpectedOverQuota,
+            resource='snapshots')