bcachefs: Fix livelock calling bch2_mark_bkey_replicas()

The bug was that we were trying to find a replicas entry that wasn't
sorted - but, we can also simplify the code by not using
bch2_mark_bkey_replicas and instead ensuring the list of replicas
entries exists directly.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_update_leaf.c

@@ -707,11 +707,9 @@ int bch2_trans_commit_error(struct btree_trans *trans,
 	case BTREE_INSERT_NEED_MARK_REPLICAS:
 		bch2_trans_unlock(trans);
 
-		trans_for_each_update(trans, i) {
-			ret = bch2_mark_bkey_replicas(c, bkey_i_to_s_c(i->k));
-			if (ret)
-				return ret;
-		}
+		ret = bch2_replicas_delta_list_mark(c, trans->fs_usage_deltas);
+		if (ret)
+			return ret;
 
 		if (bch2_trans_relock(trans))
 			return 0;

fs/bcachefs/buckets.c

@@ -565,6 +565,7 @@ static inline void update_replicas_list(struct btree_trans *trans,
 	n->delta = sectors;
 	memcpy((void *) n + offsetof(struct replicas_delta, r),
 	       r, replicas_entry_bytes(r));
+	bch2_replicas_entry_sort(&n->r);
 	d->used += b;
 }
 
@@ -615,6 +616,18 @@ int bch2_replicas_delta_list_apply(struct bch_fs *c,
 	return -1;
 }
 
+int bch2_replicas_delta_list_mark(struct bch_fs *c,
+				  struct replicas_delta_list *r)
+{
+	struct replicas_delta *d = r->d;
+	struct replicas_delta *top = (void *) r->d + r->used;
+	int ret = 0;
+
+	for (d = r->d; !ret && d != top; d = replicas_delta_next(d))
+		ret = bch2_mark_replicas(c, &d->r);
+	return ret;
+}
+
 #define do_mark_fn(fn, c, pos, flags, ...)				\
 ({									\
 	int gc, ret = 0;						\

fs/bcachefs/buckets.h

@@ -253,6 +253,8 @@ int bch2_mark_update(struct btree_trans *, struct btree_iter *,
 int bch2_replicas_delta_list_apply(struct bch_fs *,
 				   struct bch_fs_usage *,
 				   struct replicas_delta_list *);
+int bch2_replicas_delta_list_mark(struct bch_fs *,
+				  struct replicas_delta_list *);
 int bch2_trans_mark_key(struct btree_trans *, struct bkey_s_c, struct bkey_s_c,
 			unsigned, s64, unsigned);
 int bch2_trans_mark_update(struct btree_trans *, struct btree_iter *iter,