@@ -437,6 +437,9 @@ void throttle_group_register_bs(BlockDriverState *bs, const char *groupname)
* list, destroying the timers and setting the throttle_state pointer
* to NULL.
*
+ * The BlockDriverState must not have pending throttled requests, so
+ * the caller has to drain them first.
+ *
* The group will be destroyed if it's empty after this operation.
*
* @bs: the BlockDriverState to remove
@@ -446,6 +449,10 @@ void throttle_group_unregister_bs(BlockDriverState *bs)
ThrottleGroup *tg = container_of(bs->throttle_state, ThrottleGroup, ts);
int i;
+ assert(bs->pending_reqs[0] == 0 && bs->pending_reqs[1] == 0);
+ assert(qemu_co_queue_empty(&bs->throttled_reqs[0]));
+ assert(qemu_co_queue_empty(&bs->throttled_reqs[1]));
+
qemu_mutex_lock(&tg->lock);
for (i = 0; i < 2; i++) {
if (tg->tokens[i] == bs) {