Addressed the comments received on upstream PR for refactoring the fix for NFS Cancel maintenance (#131)

### Description

This PR addresses the comments received on upstream PR
apache#13897 to refactor the code
written for fixing the Cancel Maintenance where the Pool wasn't getting
mounted back in case of NFS.

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### Types of changes

- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [ ] New feature (non-breaking change which adds functionality)
- [X] Bug fix (non-breaking change which fixes an issue)
- [ ] Enhancement (improves an existing feature and functionality)
- [ ] Cleanup (Code refactoring and cleanup, that may add test cases)
- [ ] Build/CI
- [ ] Test (unit or integration test code)

### Feature/Enhancement Scale or Bug Severity

#### Feature/Enhancement Scale

- [ ] Major
- [ ] Minor

#### Bug Severity

- [ ] BLOCKER
- [ ] Critical
- [X] Major
- [ ] Minor
- [ ] Trivial

### Screenshots (if appropriate):
<img width="1045" height="339" alt="Screenshot 2026-10-22 at 8 08 49 PM"
src="https://github.com/user-attachments/assets/438b7f0e-8b45-4b39-a425-3fb4bd4451ab"
/>
<img width="1298" height="183" alt="Screenshot 2026-10-22 at 8 10 22 PM"
src="https://github.com/user-attachments/assets/58507563-828d-4ff2-b50c-0decd4674578"
/>
<img width="1049" height="358" alt="Screenshot 2026-10-22 at 8 11 18 PM"
src="https://github.com/user-attachments/assets/0ad746fd-137a-4e76-92c8-8bddf3d28692"
/>
<img width="1302" height="216" alt="Screenshot 2026-10-22 at 8 12 02 PM"
src="https://github.com/user-attachments/assets/c0efeadf-a2b6-4328-adb3-928f6bfee618"
/>
<img width="1048" height="360" alt="Screenshot 2026-10-22 at 8 13 28 PM"
src="https://github.com/user-attachments/assets/f6eae7fb-08fc-4d29-94b6-678371f0054c"
/>
<img width="1301" height="314" alt="Screenshot 2026-10-22 at 8 12 51 PM"
src="https://github.com/user-attachments/assets/0eeba7e2-2e98-4e9c-b463-5606f1838776"
/>

### How Has This Been Tested?
- Created `Primary1` storage pool of `NetworkFileSystem` type using
`DefaultPrimary` storage plugin.
- Created `testPool` storage pool of `NetworkFileSystem` type using
`NetApp ONTAP` storage plugin.
- Enter Maintenance on both the pools.
- Cancel Maintenance on both the pools.
- At each stage, both `mount | grep nfs` and libvirtd's `virst pool-list
--all` should reflect the pools appropriately.
- Before Enter Maintenance, both the commands should have mount and pool
listed respectively.
   - On Enter Maintenance, neither should be listed.
   - On Cancel Maintenance, both should be listed again.

Author: sandeeplocharla

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/KVMHAMonitor.java

@@ -50,6 +50,12 @@ public void addStoragePool(HAStoragePool pool) {
         }
     }
 
+    public void unregisterStoragePool(String uuid) {
+        synchronized (haStoragePools) {
+            haStoragePools.remove(uuid);
+        }
+    }
+
     public void removeStoragePool(String uuid) {
         synchronized (haStoragePools) {
             HAStoragePool pool = haStoragePools.get(uuid);

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/KVMStoragePoolManager.java

@@ -457,11 +457,12 @@ public synchronized boolean deleteStoragePool(StoragePoolType type, String uuid)
 
     public boolean deleteStoragePool(StoragePoolType type, String uuid, Map<String, String> details) {
         StorageAdaptor adaptor = getStorageAdaptor(type);
-        // For NetworkFilesystem, libvirt will take care of unmounting the nfs mount. If nfs mount has been removed before libvirt's pool
-        // delete, libvirt will throw an error.
-        boolean deleteStatus = adaptor.deleteStoragePool(uuid, details);
+        boolean deleteStatus;
         if (type == StoragePoolType.NetworkFilesystem) {
-            _haMonitor.removeStoragePool(uuid);
+            _haMonitor.unregisterStoragePool(uuid);
+            deleteStatus = adaptor.deleteStoragePool(uuid);
+        } else {
+            deleteStatus = adaptor.deleteStoragePool(uuid, details);
         }
         synchronized (_storagePools) {
             _storagePools.remove(uuid);

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/LibvirtStorageAdaptor.java

@@ -891,11 +891,6 @@ private boolean destroyStoragePoolHandleException(Connect conn, String uuid)
         return false;
     }
 
-    @Override
-    public boolean deleteStoragePool(String uuid, Map<String, String> details) {
-        return deleteStoragePool(uuid);
-    }
-
     @Override
     public boolean deleteStoragePool(String uuid) {
         logger.info("Attempting to remove storage pool " + uuid + " from libvirt");

server/src/main/java/com/cloud/storage/StorageManagerImpl.java

@@ -1276,7 +1276,7 @@ public PrimaryDataStoreInfo updateStoragePool(UpdateStoragePoolCmd cmd) throws I
         if (capacityBytes != null) {
             if (capacityBytes != pool.getCapacityBytes()) {
                 updatedCapacityBytes = capacityBytes;
-                 details.put(PrimaryDataStoreLifeCycle.CAPACITY_BYTES, String.valueOf(updatedCapacityBytes));
+                details.put(PrimaryDataStoreLifeCycle.CAPACITY_BYTES, String.valueOf(updatedCapacityBytes));
                 changes = true;
             }
         }
@@ -1286,7 +1286,7 @@ public PrimaryDataStoreInfo updateStoragePool(UpdateStoragePoolCmd cmd) throws I
         if (capacityIops != null) {
             if (!capacityIops.equals(pool.getCapacityIops())) {
                 updatedCapacityIops = capacityIops;
-                 details.put(PrimaryDataStoreLifeCycle.CAPACITY_IOPS, String.valueOf(updatedCapacityIops));
+                details.put(PrimaryDataStoreLifeCycle.CAPACITY_IOPS, String.valueOf(updatedCapacityIops));
                 changes = true;
             }
         }