mgr/smb: add threading lock for SqliteStore

Fixes: https://tracker.ceph.com/issues/69886
Signed-off-by: Pedro Gonzalez Gomez <[email protected]>

Author: Pegonzal

src/pybind/mgr/smb/sqlite_store.py

@@ -21,6 +21,7 @@
 import copy
 import json
 import logging
+import threading
 
 from .config_store import ObjectCachingEntry
 from .proto import (
@@ -257,6 +258,7 @@ def __init__(self, backend: DBAcessor, tables: Iterable[Table]) -> None:
         self._tables: Dict[str, Table] = {t.namespace: t for t in tables}
         self._prepared = False
         self._cursor: Optional[Cursor] = None
+        self._db_lock = threading.Lock()
 
     def _prepare_tables(self) -> None:
         """Automatic/internal table preparation."""
@@ -281,7 +283,7 @@ def _table(self, key: Union[str, EntryKey]) -> Table:
     @contextlib.contextmanager
     def transaction(self) -> Iterator[None]:
         """Explicitly start a DB transaction."""
-        with self._db():
+        with self._db_lock, self._db():
             assert self._cursor
             self._cursor.execute('BEGIN;')
             yield None