chore(cinder-understack): add functions to track SVM for a pool

We need to be able to track the SVM with a pool. Unfortunately flexvols
which are 1:1 with pool names for a backend are unique in a SVM but they
can be repeated between SVMs. So we must prefix the pool name with our
SVM name and then strip it off when we need just the pool name.

Author: nidzrai

python/cinder-understack/cinder_understack/dynamic_netapp_driver.py

@@ -1,5 +1,7 @@
 """NetApp NVMe driver with dynamic multi-SVM support."""
 
+from contextlib import contextmanager
+
 from cinder import context
 from cinder import exception
 from cinder import interface
@@ -853,6 +855,11 @@ def create_volume(self, volume):
             ) from e
 
 
+# We use a + because of the special meaning of # in
+# cinder/volume/volume_utils.py extract_host()
+_SVM_NAME_DELIM = "+"
+
+
 class NetAppMinimalLibrary(NetAppNVMeStorageLibrary):
     """Minimal overriding library.
 
@@ -949,6 +956,32 @@ def check_for_setup_error(self):
         """Check for setup errors."""
         self.library.check_for_setup_error()
 
+    def _svmify_pool(self, pool: dict, svm_name: str, **kwargs) -> dict:
+        """Applies SVM info to a pool so we can target it and track it."""
+        # We need to prefix our pool_name, which is 1:1 with the FlexVol
+        # name on the SVM, with the SVM name. This is because the name of
+        # a FlexVol is unique within 1 SVM. Two different SVMs can have
+        # the same FlexVol however so we need to prefix it. We avoid
+        # using # as our separator because it has special meaning to
+        # cinder. See the cinder/volume/volume_utils.py extract_host()
+        # function for details.
+        pool_name = pool["pool_name"]
+        pool["pool_name"] = f"{svm_name}{_SVM_NAME_DELIM}{pool_name}"
+        pool["netapp_vserver"] = svm_name
+        pool.update(kwargs)
+        return pool
+
+    @contextmanager
+    def _fix_volume_pool_name(self, svm_name: str, volume):
+        """Strips out the SVM name from the volume host and restores."""
+        original_host = volume.get("host")
+        if not original_host:
+            yield original_host
+        else:
+            volume["host"] = original_host.replace(f"{svm_name}{_SVM_NAME_DELIM}", "")
+            yield volume
+            volume["host"] = original_host
+
     def create_volume(self, volume):
         """Create a volume."""
         return self.library.create_volume(volume)