refactor(linstor): add GC volume deletion helper

This adds the `mark_volume_for_deletion` function on the LINSTOR volume
manager to have a common implementation for marking a volume for later
deletion by the GC.

This also adds a constant that holds the volume UUID prefix that gets
added to such volumes to avoid duplicating this prefix in multiple
places.

Signed-off-by: Alexandre Sollier <alexandre.sollier@vates.tech>

Author: Kuruyia

drivers/LinstorSR.py

@@ -27,6 +27,7 @@
     from linstorvolumemanager import LinstorVolumeManagerError
     from linstorvolumemanager import DATABASE_VOLUME_NAME
     from linstorvolumemanager import PERSISTENT_PREFIX
+    from linstorvolumemanager import DELETED_PREFIX
 
     LINSTOR_AVAILABLE = True
 except ImportError:
@@ -1114,7 +1115,7 @@ def _load_vdis_ex(self):
                 if not introduce:
                     continue
 
-                if vdi_uuid.startswith('DELETED_'):
+                if vdi_uuid.startswith(DELETED_PREFIX):
                     continue
 
                 volume_metadata = volumes_metadata.get(vdi_uuid)
@@ -1479,9 +1480,7 @@ def _undo_clone(self, volume_names, vdi_uuid, base_uuid, snap_uuid):
                 # volume info remains... The problem is we can't rename
                 # properly the base VDI below this line, so we must change the
                 # UUID of this bad VDI before.
-                self._linstor.update_volume_uuid(
-                    vdi_uuid, 'DELETED_' + vdi_uuid, force=True
-                )
+                self._linstor.mark_volume_for_deletion(vdi_uuid, force=True)
 
         # Rename!
         self._linstor.update_volume_uuid(base_uuid, vdi_uuid)

drivers/cleanup.py

@@ -61,6 +61,7 @@
     from linstorvolumemanager import get_controller_uri
     from linstorvolumemanager import LinstorVolumeManager, LinstorVolumeManagerError, LinstorVolumeOpeners
     from linstorvolumemanager import PERSISTENT_PREFIX as LINSTOR_PERSISTENT_PREFIX
+    from linstorvolumemanager import DELETED_PREFIX as LINSTOR_DELETED_PREFIX
 
     LINSTOR_AVAILABLE = True
 except ImportError:
@@ -2916,7 +2917,7 @@ def _doCoalesceLeaf(self, vdi: VDI, coalesce_on_remote: bool):
             vdi._coalesceCowImageOnHost(host_ref, vdi) # vdi is the leaf for the online coalesce
             util.fistpoint.activate("LVHDRT_coaleaf_after_coalesce", self.uuid)
             vdi.pause(failfast=True)
-            # We make a pause here after the online coalesce but before the rename so we can refresh the chain for tapdisk. 
+            # We make a pause here after the online coalesce but before the rename so we can refresh the chain for tapdisk.
             # It's also needed to be paused for the rename on slaves with LVMSR.
             # We let the caller `_liveLeafCoalesce` do the unpause with the call to `vdi.ensureUnpaused()`
         else:
@@ -3744,7 +3745,7 @@ def handle_fail(vdi_uuid, e):
                 if not volume_info.name and not list(volume_metadata.items()):
                     continue  # Ignore it, probably deleted.
 
-                if vdi_uuid.startswith('DELETED_'):
+                if vdi_uuid.startswith(LINSTOR_DELETED_PREFIX):
                     # Assume it's really a RAW volume of a failed snap without COW header/footer.
                     # We must remove this VDI now without adding it in the VDI list.
                     # Otherwise `Relinking` calls and other actions can be launched on it.

drivers/linstorvolumemanager.py

@@ -37,6 +37,9 @@
 # Persistent prefix to add to RAW persistent volumes.
 PERSISTENT_PREFIX = 'xcp-persistent-'
 
+# Prefix added to the UUID of a LINSTOR volume that will be deleted by the GC.
+DELETED_PREFIX = 'DELETED_'
+
 # Contains the data of the "/var/lib/linstor" directory.
 DATABASE_VOLUME_NAME = PERSISTENT_PREFIX + 'database'
 DATABASE_SIZE = 1 << 30  # 1GB.
@@ -1143,6 +1146,20 @@ def update_volume_uuid(self, volume_uuid, new_volume_uuid, force=False):
             )
         )
 
+    def mark_volume_for_deletion(self, volume_uuid, force=False):
+        """
+        Add a prefix to the volume UUID to mark it for deletion by the GC.
+        :param str volume_uuid: The volume to mark.
+        :param bool force: Whether to force-update the volume UUID. See the
+        documentation of `update_volume_uuid` for more details.
+        """
+        if volume_uuid.startswith(DELETED_PREFIX):
+            return
+
+        self.update_volume_uuid(
+            volume_uuid, DELETED_PREFIX + volume_uuid, force=force
+        )
+
     def update_volume_name(self, volume_uuid, volume_name):
         """
         Change the volume name of a volume.
@@ -2599,10 +2616,7 @@ def _build_volumes(self, repair):
                 # This prefix is mandatory if it exists a snap transaction to
                 # rollback because the original VDI UUID can try to be renamed
                 # with the UUID we are trying to delete...
-                if not volume_uuid.startswith('DELETED_'):
-                    self.update_volume_uuid(
-                        volume_uuid, 'DELETED_' + volume_uuid, force=True
-                    )
+                self.mark_volume_for_deletion(volume_uuid, force=True)
 
         for dest_uuid, src_uuid in updating_uuid_volumes.items():
             dest_namespace = self._build_volume_namespace(dest_uuid)