bcachefs: bch2_btree_bit_mod()

Provide a non-write buffer version of bch2_btree_bit_mod_buffered(), for
the subvolume children btree.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_update.c

@@ -785,6 +785,27 @@ int bch2_btree_delete_range(struct bch_fs *c, enum btree_id id,
 	return ret;
 }
 
+int bch2_btree_bit_mod(struct btree_trans *trans, enum btree_id btree,
+		       struct bpos pos, bool set)
+{
+	struct bkey_i *k = bch2_trans_kmalloc(trans, sizeof(*k));
+	int ret = PTR_ERR_OR_ZERO(k);
+	if (ret)
+		return ret;
+
+	bkey_init(&k->k);
+	k->k.type = set ? KEY_TYPE_set : KEY_TYPE_deleted;
+	k->k.p = pos;
+
+	struct btree_iter iter;
+	bch2_trans_iter_init(trans, &iter, btree, pos, BTREE_ITER_INTENT);
+
+	ret   = bch2_btree_iter_traverse(&iter) ?:
+		bch2_trans_update(trans, &iter, k, 0);
+	bch2_trans_iter_exit(trans, &iter);
+	return ret;
+}
+
 int bch2_btree_bit_mod_buffered(struct btree_trans *trans, enum btree_id btree,
 				struct bpos pos, bool set)
 {

fs/bcachefs/btree_update.h

@@ -62,6 +62,7 @@ int bch2_btree_delete_range_trans(struct btree_trans *, enum btree_id,
 int bch2_btree_delete_range(struct bch_fs *, enum btree_id,
 			    struct bpos, struct bpos, unsigned, u64 *);
 
+int bch2_btree_bit_mod(struct btree_trans *, enum btree_id, struct bpos, bool);
 int bch2_btree_bit_mod_buffered(struct btree_trans *, enum btree_id, struct bpos, bool);
 
 static inline int bch2_btree_delete_at_buffered(struct btree_trans *trans,