bcachefs: btree_trans_too_many_iters() is now a transaction restart

All transaction restarts need a tracepoint - this is essential for
debugging
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_iter.h

@@ -4,6 +4,7 @@
 
 #include "bset.h"
 #include "btree_types.h"
+#include "trace.h"
 
 static inline void __btree_path_get(struct btree_path *path, bool intent)
 {
@@ -384,8 +385,12 @@ static inline struct bkey_s_c bch2_btree_iter_peek_upto_type(struct btree_iter *
 
 static inline int btree_trans_too_many_iters(struct btree_trans *trans)
 {
-	return hweight64(trans->paths_allocated) > BTREE_ITER_MAX / 2
-		? -EINTR : 0;
+	if (hweight64(trans->paths_allocated) > BTREE_ITER_MAX / 2) {
+		trace_trans_restart_too_many_iters(trans->fn, _THIS_IP_);
+		return btree_trans_restart(trans);
+	}
+
+	return 0;
 }
 
 static inline struct bkey_s_c

fs/bcachefs/trace.h

@@ -755,6 +755,12 @@ DEFINE_EVENT(transaction_event,	trans_restart_key_cache_raced,
 	TP_ARGS(trans_fn, caller_ip)
 );
 
+DEFINE_EVENT(transaction_event,	trans_restart_too_many_iters,
+	TP_PROTO(const char *trans_fn,
+		 unsigned long caller_ip),
+	TP_ARGS(trans_fn, caller_ip)
+);
+
 DECLARE_EVENT_CLASS(transaction_restart_iter,
 	TP_PROTO(const char *trans_fn,
 		 unsigned long caller_ip,