Basic working FileSR vdi_revert

Signed-off-by: Antoine Bartuccio <antoine.bartuccio@vates.tech>

Author: klmp200

drivers/FileSR.py

@@ -777,25 +777,27 @@ def revert(self, sr_uuid, src_uuid, dest_uuid):
         if not dest._checkpath(dest.path):
             raise xs_errors.XenError(f"Could not find {dest.path}")
 
-        def get_child_of(start: FileVDI, parent_uuid: str) -> Optional[str]:
-            util.SMlog(f"Looking for common parent: {parent_uuid}")
-            current = start.uuid
-            while current is not None:
-                path, _ = start._get_path_and_type(current)
-                util.SMlog(f"Testing path {path}")
-                if not path:
-                    return None
+        def get_child_of(sr: FileSR, uuid: str, exclude: Optional[List[str]] = None) -> Optional[str]:
+            if not exclude:
+                exclude = []
 
-                parent = start.cowutil.getParent(path, FileVDI.extractUuid)
-                util.SMlog(f"Testing {parent} == {parent_uuid}")
-                if parent == parent_uuid:
-                    util.SMlog(f"Found {current} with next parent {parent}")
-                    return current
-                current = parent
+            excluded = set(exclude)
+            sr._loadvdis()
 
-            return None
+            children = []
+
+            for vdi in sr.vdis.values():
+                if vdi.uuid == uuid:
+                    continue
+                if vdi.parent == uuid and vdi.uuid not in excluded:
+                    children.append(vdi.uuid)
+
+            if len(children) != 1:
+                return None
+
+            return children[0]
 
-        common_parent_uuid = get_child_of(dest, self.parent)
+        common_parent_uuid = self.parent if self.parent == dest.parent else get_child_of(self.sr, self.parent, [self.uuid])
         if not common_parent_uuid:
             raise xs_errors.XenError(f"{self.uuid} and {dest.uuid} aren't on the same snapshot tree")
 
@@ -884,7 +886,7 @@ def update_vdi_from_file(vdi: FileVDI, path: str):
 
             dest._db_update()
 
-        return dest.get_params()
+        return
 
 
             # except util.CommandException as inst: