bcachefs: bch2_btree_delete_extent_at()

New helper, for deleting extents.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/alloc_background.c

@@ -706,7 +706,6 @@ static int bch2_check_discard_freespace_key(struct btree_trans *trans,
 	struct bch_alloc_v4 a;
 	u64 genbits;
 	struct bpos pos;
-	struct bkey_i *update;
 	enum bch_data_type state = iter->btree_id == BTREE_ID_need_discard
 		? BCH_DATA_need_discard
 		: BCH_DATA_free;
@@ -756,21 +755,8 @@ static int bch2_check_discard_freespace_key(struct btree_trans *trans,
 	printbuf_exit(&buf);
 	return ret;
 delete:
-	if (iter->btree_id == BTREE_ID_freespace) {
-		/* should probably add a helper for deleting extents */
-		update = bch2_trans_kmalloc(trans, sizeof(*update));
-		ret = PTR_ERR_OR_ZERO(update);
-		if (ret)
-			goto err;
-
-		bkey_init(&update->k);
-		update->k.p = iter->pos;
-		bch2_key_resize(&update->k, 1);
-
-		ret = bch2_trans_update(trans, iter, update, 0);
-	} else {
-		ret = bch2_btree_delete_at(trans, iter, 0);
-	}
+	ret = bch2_btree_delete_extent_at(trans, iter,
+			iter->btree_id == BTREE_ID_freespace ? 1 : 0, 0);
 	goto out;
 }
 

fs/bcachefs/btree_update.h

@@ -51,6 +51,8 @@ enum btree_insert_flags {
 #define BCH_HASH_SET_MUST_CREATE	(1 << __BCH_HASH_SET_MUST_CREATE)
 #define BCH_HASH_SET_MUST_REPLACE	(1 << __BCH_HASH_SET_MUST_REPLACE)
 
+int bch2_btree_delete_extent_at(struct btree_trans *, struct btree_iter *,
+				unsigned, unsigned);
 int bch2_btree_delete_at(struct btree_trans *, struct btree_iter *, unsigned);
 
 int __bch2_btree_insert(struct btree_trans *, enum btree_id, struct bkey_i *);

fs/bcachefs/btree_update_leaf.c

@@ -1697,8 +1697,8 @@ int bch2_btree_insert(struct bch_fs *c, enum btree_id id,
 			     __bch2_btree_insert(&trans, id, k));
 }
 
-int bch2_btree_delete_at(struct btree_trans *trans,
-			 struct btree_iter *iter, unsigned update_flags)
+int bch2_btree_delete_extent_at(struct btree_trans *trans, struct btree_iter *iter,
+				unsigned len, unsigned update_flags)
 {
 	struct bkey_i *k;
 
@@ -1708,9 +1708,16 @@ int bch2_btree_delete_at(struct btree_trans *trans,
 
 	bkey_init(&k->k);
 	k->k.p = iter->pos;
+	bch2_key_resize(&k->k, len);
 	return bch2_trans_update(trans, iter, k, update_flags);
 }
 
+int bch2_btree_delete_at(struct btree_trans *trans,
+			 struct btree_iter *iter, unsigned update_flags)
+{
+	return bch2_btree_delete_extent_at(trans, iter, 0, update_flags);
+}
+
 int bch2_btree_delete_range_trans(struct btree_trans *trans, enum btree_id id,
 				  struct bpos start, struct bpos end,
 				  unsigned update_flags,