bcachefs: Add assertions for unexpected transaction restarts

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/btree_iter.h

@@ -427,13 +427,17 @@ __bch2_btree_iter_peek_and_restart(struct btree_trans *trans,
 
 #define lockrestart_do(_trans, _do)					\
 ({									\
+	u32 _restart_count;						\
 	int _ret;							\
 									\
 	do {								\
-		bch2_trans_begin(_trans);				\
+		_restart_count = bch2_trans_begin(_trans);		\
 		_ret = (_do);						\
 	} while (bch2_err_matches(_ret, BCH_ERR_transaction_restart));	\
 									\
+	if (!_ret)							\
+		bch2_trans_verify_not_restarted(_trans, _restart_count);\
+									\
 	_ret;								\
 })
 
@@ -474,7 +478,7 @@ __bch2_btree_iter_peek_and_restart(struct btree_trans *trans,
 			     (_start), (_flags));			\
 									\
 	while (1) {							\
-		bch2_trans_begin(_trans);				\
+		u32 _restart_count = bch2_trans_begin(_trans);		\
 		(_k) = bch2_btree_iter_peek_type(&(_iter), (_flags));	\
 		if (!(_k).k) {						\
 			_ret = 0;					\
@@ -486,6 +490,7 @@ __bch2_btree_iter_peek_and_restart(struct btree_trans *trans,
 			continue;					\
 		if (_ret)						\
 			break;						\
+		bch2_trans_verify_not_restarted(_trans, _restart_count);\
 		if (!bch2_btree_iter_advance(&(_iter)))			\
 			break;						\
 	}								\
@@ -503,7 +508,7 @@ __bch2_btree_iter_peek_and_restart(struct btree_trans *trans,
 			     (_start), (_flags));			\
 									\
 	while (1) {							\
-		bch2_trans_begin(_trans);				\
+		u32 _restart_count = bch2_trans_begin(_trans);		\
 		(_k) = bch2_btree_iter_peek_prev_type(&(_iter), (_flags));\
 		if (!(_k).k) {						\
 			_ret = 0;					\
@@ -515,6 +520,7 @@ __bch2_btree_iter_peek_and_restart(struct btree_trans *trans,
 			continue;					\
 		if (_ret)						\
 			break;						\
+		bch2_trans_verify_not_restarted(_trans, _restart_count);\
 		if (!bch2_btree_iter_rewind(&(_iter)))			\
 			break;						\
 	}								\

fs/bcachefs/btree_update_interior.c

@@ -969,6 +969,7 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
 	unsigned update_level = level;
 	int journal_flags = flags & JOURNAL_WATERMARK_MASK;
 	int ret = 0;
+	u32 restart_count = trans->restart_count;
 
 	BUG_ON(!path->should_be_locked);
 
@@ -1094,6 +1095,7 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
 	if (ret)
 		goto err;
 
+	bch2_trans_verify_not_restarted(trans, restart_count);
 	return as;
 err:
 	bch2_btree_update_free(as);