From f47be72adc41e731502463e0f43102f84ef9903d Mon Sep 17 00:00:00 2001
From: tony-saad <tony.saad@dell.com>
Date: Wed, 14 Dec 2022 17:53:09 -0800
Subject: [PATCH] Dell PowerStore: Volume caching exception support

Fixed volume caching in PowerStore driver. Volume caching stops working
after 32nd volume created from the same image due to snapshot limit per
volume in PowerStore. The driver needs to throw exception
SnapshotLimitReached to invalidate cache and start over with new volume
snapshots.

Closes-Bug: #1962824
Change-Id: I8b46d443a75bf98260394552f77c6807e405dce7
---
 .../test_volume_create_from_source.py         | 24 +++++++++++++++++++
 .../drivers/dell_emc/powerstore/client.py     |  6 +++++
 .../notes/bug-1962824-ff0cac0d35021f84.yaml   |  9 +++++++
 3 files changed, 39 insertions(+)
 create mode 100644 releasenotes/notes/bug-1962824-ff0cac0d35021f84.yaml

diff --git a/cinder/tests/unit/volume/drivers/dell_emc/powerstore/test_volume_create_from_source.py b/cinder/tests/unit/volume/drivers/dell_emc/powerstore/test_volume_create_from_source.py
index 48fa7d8c6bf..4e2920b94d5 100644
--- a/cinder/tests/unit/volume/drivers/dell_emc/powerstore/test_volume_create_from_source.py
+++ b/cinder/tests/unit/volume/drivers/dell_emc/powerstore/test_volume_create_from_source.py
@@ -19,6 +19,7 @@ from cinder import exception
 from cinder.tests.unit import fake_snapshot
 from cinder.tests.unit import fake_volume
 from cinder.tests.unit.volume.drivers.dell_emc import powerstore
+from cinder.volume.drivers.dell_emc.powerstore import client
 
 
 class TestVolumeCreateFromSource(powerstore.TestPowerStoreDriver):
@@ -114,3 +115,26 @@ class TestVolumeCreateFromSource(powerstore.TestPowerStoreDriver):
             self.source_volume
         )
         self.assertIn("Failed to extend PowerStore volume", error.msg)
+
+    @mock.patch("requests.request")
+    def test_create_snapshot_limit_reached(self, mock_create_snap_limit):
+        snapshot_limit_reached_response = {
+            'errorCode': 0,
+            'message': 'messages',
+            'messages': [
+                {
+                    'code': client.TOO_MANY_SNAPS_ERROR,
+                }
+            ]
+        }
+        mock_create_snap_limit.return_value = powerstore.MockResponse(
+            snapshot_limit_reached_response, rc=400)
+        error = self.assertRaises(
+            exception.SnapshotLimitReached,
+            self.driver.adapter.create_volume_from_source,
+            self.volume,
+            self.source_volume
+        )
+        self.assertIn(
+            "Exceeded the configured limit of 32 snapshots per volume.",
+            error.msg)
diff --git a/cinder/volume/drivers/dell_emc/powerstore/client.py b/cinder/volume/drivers/dell_emc/powerstore/client.py
index dba9a1ac378..a98df5bca94 100644
--- a/cinder/volume/drivers/dell_emc/powerstore/client.py
+++ b/cinder/volume/drivers/dell_emc/powerstore/client.py
@@ -31,6 +31,8 @@ from cinder.volume.drivers.dell_emc.powerstore import utils
 LOG = logging.getLogger(__name__)
 VOLUME_NOT_MAPPED_ERROR = "0xE0A08001000F"
 SESSION_ALREADY_FAILED_OVER_ERROR = "0xE0201005000C"
+TOO_MANY_SNAPS_ERROR = "0xE0A040010003"
+MAX_SNAPS_IN_VTREE = 32
 
 
 class PowerStoreClient(object):
@@ -271,6 +273,10 @@ class PowerStoreClient(object):
                       "entity": entity,
                       "entity_id": entity_id, })
             LOG.error(msg)
+            if ("messages" in response and
+                    response["messages"][0]["code"] == TOO_MANY_SNAPS_ERROR):
+                raise exception.SnapshotLimitReached(
+                    set_limit=MAX_SNAPS_IN_VTREE)
             raise exception.VolumeBackendAPIException(data=msg)
         return response["id"]
 
diff --git a/releasenotes/notes/bug-1962824-ff0cac0d35021f84.yaml b/releasenotes/notes/bug-1962824-ff0cac0d35021f84.yaml
new file mode 100644
index 00000000000..bb9323775e8
--- /dev/null
+++ b/releasenotes/notes/bug-1962824-ff0cac0d35021f84.yaml
@@ -0,0 +1,9 @@
+---
+fixes:
+  - |
+    PowerStore driver `bug #1962824
+    <https://bugs.launchpad.net/cinder/+bug/1962824>`_: Fixed Cinder
+    volume caching mechanism for the driver. Now the driver
+    correctly raises ``exception.SnapshotLimitReached`` when maximum
+    snapshots are created for a given volume and the volume cache is
+    invalidated to allow a new row of fast volume clones.