bcachefs: Bump limit in btree_trans_too_many_iters()

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_iter.h

@@ -642,7 +642,7 @@ int __bch2_btree_trans_too_many_iters(struct btree_trans *);
 
 static inline int btree_trans_too_many_iters(struct btree_trans *trans)
 {
-	if (bitmap_weight(trans->paths_allocated, trans->nr_paths) > BTREE_ITER_INITIAL - 8)
+	if (bitmap_weight(trans->paths_allocated, trans->nr_paths) > BTREE_ITER_NORMAL_LIMIT - 8)
 		return __bch2_btree_trans_too_many_iters(trans);
 
 	return 0;

fs/bcachefs/btree_types.h

@@ -364,7 +364,21 @@ struct btree_insert_entry {
 	unsigned long		ip_allocated;
 };
 
+/* Number of btree paths we preallocate, usually enough */
 #define BTREE_ITER_INITIAL		64
+/*
+ * Lmiit for btree_trans_too_many_iters(); this is enough that almost all code
+ * paths should run inside this limit, and if they don't it usually indicates a
+ * bug (leaking/duplicated btree paths).
+ *
+ * exception: some fsck paths
+ *
+ * bugs with excessive path usage seem to have possibly been eliminated now, so
+ * we might consider eliminating this (and btree_trans_too_many_iter()) at some
+ * point.
+ */
+#define BTREE_ITER_NORMAL_LIMIT		256
+/* never exceed limit */
 #define BTREE_ITER_MAX			(1U << 10)
 
 struct btree_trans_commit_hook;