[Fix] Fix race condition in maps loading by unlocking backend on switch

diff --git a/src/libserver/maps/map.c b/src/libserver/maps/map.c
index 51390f24bce533c557e432ac8b4b8e251e588ea6..52c3a4af61c262ee9f63a17318937ebda48c3992 100644 (file)
--- a/src/libserver/maps/map.c
+++ b/src/libserver/maps/map.c
@@ -295,6 +295,23 @@ rspamd_map_cache_cb(struct ev_loop *loop, ev_timer *w, int revents)
        }
 }
 
+/*
+ * Unlocks the current backend if locked before switching to another backend
+ */
+static void
+rspamd_map_unlock_current_backend(struct map_periodic_cbdata *cbd)
+{
+       struct rspamd_map_backend *bk;
+       struct rspamd_map *map = cbd->map;
+
+       if (cbd->locked && cbd->cur_backend < cbd->map->backends->len) {
+               bk = g_ptr_array_index(cbd->map->backends, cbd->cur_backend);
+               g_atomic_int_set(&bk->shared->locked, 0);
+               cbd->locked = FALSE;
+               msg_debug_map("unlocked current backend %s before switching", bk->uri);
+       }
+}
+
 static inline time_t
 rspamd_http_map_process_next_check(time_t now, time_t expires, time_t map_check_interval)
 {
@@ -335,6 +352,8 @@ http_map_finish(struct rspamd_http_connection *conn,
                if (cbd->check) {
                        msg_info_map("need to reread map from %s", cbd->bk->uri);
                        cbd->periodic->need_modify = TRUE;
+                       /* Unlock current backend before resetting */
+                       rspamd_map_unlock_current_backend(cbd->periodic);
                        /* Reset the whole chain */
                        cbd->periodic->cur_backend = 0;
                        /* Reset cache, old cached data will be cleaned on timeout */
@@ -526,6 +545,8 @@ http_map_finish(struct rspamd_http_connection *conn,
 
                MAP_RELEASE(cbd->shmem_data, "shmem_data");
 
+               /* Unlock current backend before switching to next */
+               rspamd_map_unlock_current_backend(cbd->periodic);
                cbd->periodic->cur_backend++;
                munmap(in, dlen);
                rspamd_map_process_periodic(cbd->periodic);
@@ -583,6 +604,8 @@ http_map_finish(struct rspamd_http_connection *conn,
                }
 
                rspamd_map_update_http_cached_file(map, bk, cbd->data);
+               /* Unlock current backend before switching to next */
+               rspamd_map_unlock_current_backend(cbd->periodic);
                cbd->periodic->cur_backend++;
                rspamd_map_process_periodic(cbd->periodic);
        }
@@ -2044,7 +2067,17 @@ rspamd_map_process_periodic(struct map_periodic_cbdata *cbd)
 
        /* For each backend we need to check for modifications */
        if (cbd->cur_backend >= cbd->map->backends->len) {
-               /* Last backend */
+               /* Last backend - unlock current backend if needed */
+               if (cbd->locked) {
+                       /* Unlock the last processed backend */
+                       struct rspamd_map_backend *last_bk;
+                       if (cbd->cur_backend > 0 && cbd->cur_backend - 1 < cbd->map->backends->len) {
+                               last_bk = g_ptr_array_index(cbd->map->backends, cbd->cur_backend - 1);
+                               g_atomic_int_set(&last_bk->shared->locked, 0);
+                               cbd->locked = FALSE;
+                               msg_debug_map("unlocked last backend %s", last_bk->uri);
+                       }
+               }
                msg_debug_map("finished map: %d of %d", cbd->cur_backend,
                                          cbd->map->backends->len);
                MAP_RELEASE(cbd, "periodic");
@@ -2067,7 +2100,7 @@ rspamd_map_process_periodic(struct map_periodic_cbdata *cbd)
                        return;
                }
                else {
-                       msg_debug_map("locked map %s", map->name);
+                       msg_debug_map("locked map %s (backend: %s)", map->name, bk->uri);
                        cbd->locked = TRUE;
                }
        }