Implement volume quota support in Cinder

parital fix for bug 1023311
  * To use needs cinderclient https://review.openstack.org/#/c/11509/
  * Updates quota classes with changes in Nova
  * Adds needed quota related DB tables
  * Updates test_quota to reflect changes in Nova
  * Adds absolute limits and empty rate limit functions
  * Updates test/integration/test_volume to make it work w/ above changes

Change-Id: I221c7a9dc51a2bb9bf7228c056f63ba9546cf5f9

cinder/db/sqlalchemy/models.py

@@ -241,8 +241,43 @@ class QuotaClass(BASE, CinderBase):
     hard_limit = Column(Integer, nullable=True)
 
 
+class QuotaUsage(BASE, CinderBase):
+    """Represents the current usage for a given resource."""
+
+    __tablename__ = 'quota_usages'
+    id = Column(Integer, primary_key=True)
+
+    project_id = Column(String(255), index=True)
+    resource = Column(String(255))
+
+    in_use = Column(Integer)
+    reserved = Column(Integer)
+
+    @property
+    def total(self):
+        return self.in_use + self.reserved
+
+    until_refresh = Column(Integer, nullable=True)
+
+
+class Reservation(BASE, CinderBase):
+    """Represents a resource reservation for quotas."""
+
+    __tablename__ = 'reservations'
+    id = Column(Integer, primary_key=True)
+    uuid = Column(String(36), nullable=False)
+
+    usage_id = Column(Integer, ForeignKey('quota_usages.id'), nullable=False)
+
+    project_id = Column(String(255), index=True)
+    resource = Column(String(255))
+
+    delta = Column(Integer)
+    expire = Column(DateTime, nullable=False)
+
+
 class Snapshot(BASE, CinderBase):
-    """Represents a block storage device that can be attached to a vm."""
+    """Represents a block storage device that can be attached to a VM."""
     __tablename__ = 'snapshots'
     id = Column(String(36), primary_key=True)