bcachefs: bch2_trans_update() is now __must_check

With snapshots, bch2_trans_update() has to check if we need a whitout,
which can cause a transaction restart, so this is important now.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/btree_update.h

@@ -73,8 +73,8 @@ int bch2_btree_node_update_key(struct btree_trans *, struct btree_iter *,
 int bch2_btree_node_update_key_get_iter(struct btree_trans *,
 				struct btree *, struct bkey_i *, bool);
 
-int bch2_trans_update(struct btree_trans *, struct btree_iter *,
-		      struct bkey_i *, enum btree_update_flags);
+int __must_check bch2_trans_update(struct btree_trans *, struct btree_iter *,
+				   struct bkey_i *, enum btree_update_flags);
 void bch2_trans_commit_hook(struct btree_trans *,
 			    struct btree_trans_commit_hook *);
 int __bch2_trans_commit(struct btree_trans *);

fs/bcachefs/btree_update_leaf.c

@@ -1312,8 +1312,8 @@ static int need_whiteout_for_snapshot(struct btree_trans *trans,
 	return ret;
 }
 
-int bch2_trans_update(struct btree_trans *trans, struct btree_iter *iter,
-		      struct bkey_i *k, enum btree_update_flags flags)
+int __must_check bch2_trans_update(struct btree_trans *trans, struct btree_iter *iter,
+				   struct bkey_i *k, enum btree_update_flags flags)
 {
 	struct btree_insert_entry *i, n;
 

fs/bcachefs/buckets.c

@@ -1549,7 +1549,9 @@ static int bch2_trans_mark_pointer(struct btree_trans *trans,
 		goto out;
 
 	bch2_alloc_pack(c, a, u);
-	bch2_trans_update(trans, &iter, &a->k, 0);
+	ret = bch2_trans_update(trans, &iter, &a->k, 0);
+	if (ret)
+		goto out;
 out:
 	bch2_trans_iter_exit(trans, &iter);
 	return ret;
@@ -1600,7 +1602,9 @@ static int bch2_trans_mark_stripe_ptr(struct btree_trans *trans,
 	stripe_blockcount_set(&s->v, p.ec.block,
 		stripe_blockcount_get(&s->v, p.ec.block) +
 		sectors);
-	bch2_trans_update(trans, &iter, &s->k_i, 0);
+	ret = bch2_trans_update(trans, &iter, &s->k_i, 0);
+	if (ret)
+		goto err;
 
 	bch2_bkey_to_replicas(&r.e, bkey_i_to_s_c(&s->k_i));
 	r.e.data_type = data_type;
@@ -1738,7 +1742,9 @@ static int bch2_trans_mark_stripe_bucket(struct btree_trans *trans,
 		u.data_type = !deleting ? data_type : 0;
 
 	bch2_alloc_pack(c, a, u);
-	bch2_trans_update(trans, &iter, &a->k, 0);
+	ret = bch2_trans_update(trans, &iter, &a->k, 0);
+	if (ret)
+		goto err;
 err:
 	bch2_trans_iter_exit(trans, &iter);
 	return ret;
@@ -2017,7 +2023,9 @@ static int __bch2_trans_mark_metadata_bucket(struct btree_trans *trans,
 	u.dirty_sectors	= sectors;
 
 	bch2_alloc_pack(c, a, u);
-	bch2_trans_update(trans, &iter, &a->k, 0);
+	ret = bch2_trans_update(trans, &iter, &a->k, 0);
+	if (ret)
+		goto out;
 out:
 	bch2_trans_iter_exit(trans, &iter);
 	return ret;

fs/bcachefs/dirent.c

@@ -367,7 +367,9 @@ int bch2_dirent_rename(struct btree_trans *trans,
 		}
 	}
 
-	bch2_trans_update(trans, &dst_iter, &new_dst->k_i, 0);
+	ret = bch2_trans_update(trans, &dst_iter, &new_dst->k_i, 0);
+	if (ret)
+		goto out;
 out_set_src:
 
 	/*
@@ -384,7 +386,9 @@ int bch2_dirent_rename(struct btree_trans *trans,
 		src_update_flags |= BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE;
 	}
 
-	bch2_trans_update(trans, &src_iter, &new_src->k_i, src_update_flags);
+	ret = bch2_trans_update(trans, &src_iter, &new_src->k_i, src_update_flags);
+	if (ret)
+		goto out;
 
 	if (mode == BCH_RENAME_EXCHANGE)
 		*src_offset = new_src->k.p.offset;

fs/bcachefs/subvolume.c

@@ -488,7 +488,7 @@ static int bch2_snapshot_node_create(struct btree_trans *trans, u32 parent,
 		n = bch2_trans_kmalloc(trans, sizeof(*n));
 		ret = PTR_ERR_OR_ZERO(n);
 		if (ret)
-			return ret;
+			goto err;
 
 		bkey_snapshot_init(&n->k_i);
 		n->k.p		= iter.pos;
@@ -498,11 +498,10 @@ static int bch2_snapshot_node_create(struct btree_trans *trans, u32 parent,
 		n->v.pad	= 0;
 		SET_BCH_SNAPSHOT_SUBVOL(&n->v, true);
 
-		bch2_trans_update(trans, &iter, &n->k_i, 0);
-
-		ret = bch2_mark_snapshot(trans, bkey_s_c_null, bkey_i_to_s_c(&n->k_i), 0);
+		ret   = bch2_trans_update(trans, &iter, &n->k_i, 0) ?:
+			bch2_mark_snapshot(trans, bkey_s_c_null, bkey_i_to_s_c(&n->k_i), 0);
 		if (ret)
-			break;
+			goto err;
 
 		new_snapids[i]	= iter.pos.offset;
 	}
@@ -536,7 +535,9 @@ static int bch2_snapshot_node_create(struct btree_trans *trans, u32 parent,
 		n->v.children[0] = cpu_to_le32(new_snapids[0]);
 		n->v.children[1] = cpu_to_le32(new_snapids[1]);
 		SET_BCH_SNAPSHOT_SUBVOL(&n->v, false);
-		bch2_trans_update(trans, &iter, &n->k_i, 0);
+		ret = bch2_trans_update(trans, &iter, &n->k_i, 0);
+		if (ret)
+			goto err;
 	}
 err:
 	bch2_trans_iter_exit(trans, &iter);
@@ -1049,7 +1050,9 @@ int bch2_subvolume_create(struct btree_trans *trans, u64 inode,
 
 	if (src_subvolid) {
 		src_subvol->v.snapshot = cpu_to_le32(new_nodes[1]);
-		bch2_trans_update(trans, &src_iter, &src_subvol->k_i, 0);
+		ret = bch2_trans_update(trans, &src_iter, &src_subvol->k_i, 0);
+		if (ret)
+			goto err;
 	}
 
 	new_subvol = bch2_trans_kmalloc(trans, sizeof(*new_subvol));
@@ -1064,7 +1067,9 @@ int bch2_subvolume_create(struct btree_trans *trans, u64 inode,
 	SET_BCH_SUBVOLUME_RO(&new_subvol->v, ro);
 	SET_BCH_SUBVOLUME_SNAP(&new_subvol->v, src_subvolid != 0);
 	new_subvol->k.p		= dst_iter.pos;
-	bch2_trans_update(trans, &dst_iter, &new_subvol->k_i, 0);
+	ret = bch2_trans_update(trans, &dst_iter, &new_subvol->k_i, 0);
+	if (ret)
+		goto err;
 
 	*new_subvolid	= new_subvol->k.p.offset;
 	*new_snapshotid	= new_nodes[0];

fs/bcachefs/tests.c

@@ -584,10 +584,10 @@ static int rand_mixed_trans(struct btree_trans *trans,
 	if (!(i & 3) && k.k) {
 		bkey_cookie_init(&cookie->k_i);
 		cookie->k.p = iter->pos;
-		bch2_trans_update(trans, iter, &cookie->k_i, 0);
+		ret = bch2_trans_update(trans, iter, &cookie->k_i, 0);
 	}
 
-	return 0;
+	return ret;
 }
 
 static int rand_mixed(struct bch_fs *c, u64 nr)