[Dell EMC Unity] Support create share smaller than 3 GB

The minimum file system on Unity is 3 GB. This patch changes
driver to create 3 GB underlying file system for shares
smaller than 3 GB.

DocImpact
Change-Id: Ida6ad9ad7e752c25b53390f0fee327c594e03f9f
Closes-Bug: 1648316

manila/share/drivers/dell_emc/plugins/unity/client.py

@@ -18,6 +18,7 @@ import six
 
 from oslo_log import log
 from oslo_utils import importutils
+from oslo_utils import units
 
 storops = importutils.try_import('storops')
 if storops:
@@ -30,6 +31,9 @@ from manila.i18n import _, _LI, _LE
 
 LOG = log.getLogger(__name__)
 
+# Minimun file system size in Unity
+MIN_FS_SIZE_IN_GB = 3
+
 
 class UnityClient(object):
     def __init__(self, host, username, password):
@@ -69,16 +73,16 @@ class UnityClient(object):
         except storops_ex.UnityNfsShareNameExistedError:
             return self.get_share(share_name, 'NFS')
 
-    @staticmethod
-    def create_nfs_filesystem_and_share(
-            pool, nas_server, share_name, size):
+    def create_nfs_filesystem_and_share(self, pool, nas_server,
+                                        share_name, size_gb):
         """Create filesystem and share from pool/NAS server.
 
         :param pool: pool for file system creation
         :param nas_server: nas server for file system creation
         :param share_name: file system and share name
-        :param size: file system size
+        :param size_gb: file system size
         """
+        size = self.get_valid_fs_size_in_byte(size_gb)
         pool.create_nfs_share(
             nas_server, share_name, size)
 
@@ -98,8 +102,9 @@ class UnityClient(object):
     def delete_share(share):
         share.delete()
 
-    def create_filesystem(self, pool, nas_server, share_name, size, proto):
+    def create_filesystem(self, pool, nas_server, share_name, size_gb, proto):
         try:
+            size = self.get_valid_fs_size_in_byte(size_gb)
             return pool.create_filesystem(nas_server,
                                           share_name,
                                           size,
@@ -272,3 +277,20 @@ class UnityClient(object):
                 link_up_ports.append(port)
 
         return link_up_ports
+
+    @staticmethod
+    def get_valid_fs_size_in_byte(size_gb):
+        if size_gb < MIN_FS_SIZE_IN_GB:
+            LOG.debug('Using %(min_size)s GB file system for shares less than '
+                      '%(min_size)s GB.', {'min_size': MIN_FS_SIZE_IN_GB})
+            size_gb = MIN_FS_SIZE_IN_GB
+        return size_gb * units.Gi
+
+    def extend_filesystem(self, fs, new_size_gb):
+        size = self.get_valid_fs_size_in_byte(new_size_gb)
+        try:
+            fs.extend(size)
+        except storops_ex.UnityNothingToModifyError:
+            LOG.debug('The size of the file system %(id)s is %(size)s '
+                      'bytes.', {'id': fs.get_id(), 'size': size})
+        return size

manila/share/drivers/dell_emc/plugins/unity/connection.py

@@ -17,7 +17,6 @@
 from oslo_log import log
 from oslo_utils import excutils
 from oslo_utils import importutils
-from oslo_utils import units
 
 storops = importutils.try_import('storops')
 if storops:
@@ -98,7 +97,7 @@ class UnityStorageConnection(driver.StorageConnection):
     def create_share(self, context, share, share_server=None):
         """Create a share and export it based on protocol used."""
         share_name = share['id']
-        size = share['size'] * units.Gi
+        size = share['size']
 
         # Check share's protocol.
         # Throw an exception immediately if it is an invalid protocol.
@@ -205,7 +204,8 @@ class UnityStorageConnection(driver.StorageConnection):
                                               share['share_proto'])
 
         if not self._is_share_from_snapshot(backend_share):
-            backend_share.filesystem.extend(new_size * units.Gi)
+            self.client.extend_filesystem(backend_share.filesystem,
+                                          new_size)
         else:
             share_id = share['id']
             reason = _LE("Driver does not support extending a "

manila/tests/share/drivers/dell_emc/plugins/unity/fake_exceptions.py

@@ -64,3 +64,7 @@ class UnityNfsAlreadyEnabledError(UnityException):
 
 class UnityHostNotFoundException(UnityException):
     pass
+
+
+class UnityNothingToModifyError(UnityException):
+    pass

manila/tests/share/drivers/dell_emc/plugins/unity/mocked_unity.yaml

@@ -972,3 +972,11 @@ test_get_storage_processor:
   unity:
     _methods:
       get_sp: *sp_a
+
+test_extend_filesystem:
+  fs:
+    _methods:
+      get_id: 'svc_12'
+      extend:
+        _raise:
+          UnityNothingToModifyError:

manila/tests/share/drivers/dell_emc/plugins/unity/test_client.py

@@ -13,11 +13,15 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import ddt
+from oslo_utils import units
+
 from manila import exception
 from manila import test
 from manila.tests.share.drivers.dell_emc.plugins.unity import res_mock
 
 
+@ddt.ddt
 class TestClient(test.TestCase):
     @res_mock.mock_client_input
     @res_mock.patch_client
@@ -166,3 +170,20 @@ class TestClient(test.TestCase):
         sp = client.get_storage_processor(sp_id='SPA')
 
         self.assertEqual('SPA', sp.name)
+
+    @ddt.data((1, 3), (2, 3), (3, 3), (4, 4), (10, 10))
+    @ddt.unpack
+    @res_mock.patch_client
+    def test_get_valid_fs_size(self, client, share_size_gb, fs_size_gb):
+        size = client.get_valid_fs_size_in_byte(share_size_gb)
+
+        self.assertEqual(fs_size_gb * units.Gi, size)
+
+    @res_mock.mock_client_input
+    @res_mock.patch_client
+    def test_extend_filesystem(self, client, mocked_input):
+        fs = mocked_input['fs']
+
+        size = client.extend_filesystem(fs, 5)
+
+        self.assertEqual(5 * units.Gi, size)

releasenotes/notes/unity-drvier-support-1gb-share-48f032dff8a6a789.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - Shares under 3 GB cannot be created on the Dell EMC Unity back end. If users
+    create shares smaller than 3 GB, they will be allocated a 3 GB file system on
+    the Unity system.