free the cluster cluster context if no longer used by any bdev

Signed-off-by: Alexander Indenbaum <[email protected]>

control/grpc.py

@@ -233,12 +233,30 @@ def _put_cluster(self, name: str) -> None:
             if name in self.clusters[anagrp]:
                 self.clusters[anagrp][name] -= 1
                 assert self.clusters[anagrp][name] >= 0
+                # free the cluster cluster context if no longer used by any bdev
+                if self.clusters[anagrp][name] == 0:
+                    ret = rpc_bdev.bdev_rbd_unregister_cluster(
+                        self.spdk_rpc_client,
+                        name = name
+                    )
+                    self.logger.info(f"Free cluster {name=} {ret=}")
+                    assert ret
+                    self.clusters[anagrp].pop(name)
                 return
         assert False # we should find the cluster in our state
 
+    def _alloc_cluster_name(self, anagrp: int) -> str:
+        """Allocates a new cluster name for ana group"""
+        x = 0
+        while True:
+            name = f"cluster_context_{anagrp}_{x}"
+            if name not in self.clusters[anagrp]:
+                return name
+            x += 1
+
     def _alloc_cluster(self, anagrp: int) -> str:
         """Allocates a new Rados cluster context"""
-        name = f"cluster_context_{anagrp}_{len(self.clusters[anagrp])}"
+        name = self._alloc_cluster_name(anagrp)
         nonce = rpc_bdev.bdev_rbd_register_cluster(
             self.spdk_rpc_client,
             name = name,