bcachefs: btree_node_(rewrite|update_key) cleanup

Factor out get_iter_to_node() and use it for
btree_node_rewrite_get_iter(), to be used for fixing btree node write
error behaviour.

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

3 files changed, 61 insertions, 55 deletions

diff --git a/fs/bcachefs/btree_update_interior.c b/fs/bcachefs/btree_update_interior.c
index e4e7c804625e..05aa9e32adf4 100644
--- a/fs/bcachefs/btree_update_interior.c
+++ b/fs/bcachefs/btree_update_interior.c
@@ -2126,6 +2126,31 @@ err_free_update:
 	goto out;
 }
 
+static int get_iter_to_node(struct btree_trans *trans, struct btree_iter *iter,
+			    struct btree *b)
+{
+	bch2_trans_node_iter_init(trans, iter, b->c.btree_id, b->key.k.p,
+				  BTREE_MAX_DEPTH, b->c.level,
+				  BTREE_ITER_intent);
+	int ret = bch2_btree_iter_traverse(iter);
+	if (ret)
+		goto err;
+
+	/* has node been freed? */
+	if (btree_iter_path(trans, iter)->l[b->c.level].b != b) {
+		/* node has been freed: */
+		BUG_ON(!btree_node_dying(b));
+		ret = -BCH_ERR_btree_node_dying;
+		goto err;
+	}
+
+	BUG_ON(!btree_node_hashed(b));
+	return 0;
+err:
+	bch2_trans_iter_exit(trans, iter);
+	return ret;
+}
+
 int bch2_btree_node_rewrite(struct btree_trans *trans,
 			    struct btree_iter *iter,
 			    struct btree *b,
@@ -2191,66 +2216,58 @@ err:
 	goto out;
 }
 
-struct async_btree_rewrite {
-	struct bch_fs		*c;
-	struct work_struct	work;
-	struct list_head	list;
-	enum btree_id		btree_id;
-	unsigned		level;
-	struct bkey_buf		key;
-};
-
-static int async_btree_node_rewrite_trans(struct btree_trans *trans,
-					  struct async_btree_rewrite *a)
+static int bch2_btree_node_rewrite_key(struct btree_trans *trans,
+				       enum btree_id btree, unsigned level,
+				       struct bkey_i *k, unsigned flags)
 {
 	struct btree_iter iter;
 	bch2_trans_node_iter_init(trans, &iter,
-				  a->btree_id, a->key.k->k.p,
-				  BTREE_MAX_DEPTH, a->level, 0);
+				  btree, k->k.p,
+				  BTREE_MAX_DEPTH, level, 0);
 	struct btree *b = bch2_btree_iter_peek_node(&iter);
 	int ret = PTR_ERR_OR_ZERO(b);
 	if (ret)
 		goto out;
 
-	bool found = b && btree_ptr_hash_val(&b->key) == btree_ptr_hash_val(a->key.k);
+	bool found = b && btree_ptr_hash_val(&b->key) == btree_ptr_hash_val(k);
 	ret = found
-		? bch2_btree_node_rewrite(trans, &iter, b, 0)
+		? bch2_btree_node_rewrite(trans, &iter, b, flags)
 		: -ENOENT;
+out:
+	bch2_trans_iter_exit(trans, &iter);
+	return ret;
+}
 
-#if 0
-	/* Tracepoint... */
-	if (!ret || ret == -ENOENT) {
-		struct bch_fs *c = trans->c;
-		struct printbuf buf = PRINTBUF;
+int bch2_btree_node_rewrite_key_get_iter(struct btree_trans *trans,
+					 struct btree *b, unsigned flags)
+{
+	struct btree_iter iter;
+	int ret = get_iter_to_node(trans, &iter, b);
+	if (ret)
+		return ret == -BCH_ERR_btree_node_dying ? 0 : ret;
 
-		if (!ret) {
-			prt_printf(&buf, "rewrite node:\n  ");
-			bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(a->key.k));
-		} else {
-			prt_printf(&buf, "node to rewrite not found:\n  want: ");
-			bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(a->key.k));
-			prt_printf(&buf, "\n  got:  ");
-			if (b)
-				bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
-			else
-				prt_str(&buf, "(null)");
-		}
-		bch_info(c, "%s", buf.buf);
-		printbuf_exit(&buf);
-	}
-#endif
-out:
+	ret = bch2_btree_node_rewrite(trans, &iter, b, flags);
 	bch2_trans_iter_exit(trans, &iter);
 	return ret;
 }
 
+struct async_btree_rewrite {
+	struct bch_fs		*c;
+	struct work_struct	work;
+	struct list_head	list;
+	enum btree_id		btree_id;
+	unsigned		level;
+	struct bkey_buf		key;
+};
+
 static void async_btree_node_rewrite_work(struct work_struct *work)
 {
 	struct async_btree_rewrite *a =
 		container_of(work, struct async_btree_rewrite, work);
 	struct bch_fs *c = a->c;
 
-	int ret = bch2_trans_do(c, async_btree_node_rewrite_trans(trans, a));
+	int ret = bch2_trans_do(c, bch2_btree_node_rewrite_key(trans,
+						a->btree_id, a->level, a->key.k, 0));
 	if (ret != -ENOENT)
 		bch_err_fn_ratelimited(c, ret);
 
@@ -2494,30 +2511,15 @@ int bch2_btree_node_update_key_get_iter(struct btree_trans *trans,
 					unsigned commit_flags, bool skip_triggers)
 {
 	struct btree_iter iter;
-	int ret;
-
-	bch2_trans_node_iter_init(trans, &iter, b->c.btree_id, b->key.k.p,
-				  BTREE_MAX_DEPTH, b->c.level,
-				  BTREE_ITER_intent);
-	ret = bch2_btree_iter_traverse(&iter);
+	int ret = get_iter_to_node(trans, &iter, b);
 	if (ret)
-		goto out;
-
-	/* has node been freed? */
-	if (btree_iter_path(trans, &iter)->l[b->c.level].b != b) {
-		/* node has been freed: */
-		BUG_ON(!btree_node_dying(b));
-		goto out;
-	}
-
-	BUG_ON(!btree_node_hashed(b));
+		return ret == -BCH_ERR_btree_node_dying ? 0 : ret;
 
 	bch2_bkey_drop_ptrs(bkey_i_to_s(new_key), ptr,
 			    !bch2_bkey_has_device(bkey_i_to_s(&b->key), ptr->dev));
 
 	ret = bch2_btree_node_update_key(trans, &iter, b, new_key,
 					 commit_flags, skip_triggers);
-out:
 	bch2_trans_iter_exit(trans, &iter);
 	return ret;
 }
diff --git a/fs/bcachefs/btree_update_interior.h b/fs/bcachefs/btree_update_interior.h
index 26d646e1275c..9261a9a341fb 100644
--- a/fs/bcachefs/btree_update_interior.h
+++ b/fs/bcachefs/btree_update_interior.h
@@ -169,6 +169,9 @@ static inline int bch2_foreground_maybe_merge(struct btree_trans *trans,
 
 int bch2_btree_node_rewrite(struct btree_trans *, struct btree_iter *,
 			    struct btree *, unsigned);
+int bch2_btree_node_rewrite_key_get_iter(struct btree_trans *,
+					 struct btree *, unsigned);
+
 void bch2_btree_node_rewrite_async(struct bch_fs *, struct btree *);
 int bch2_btree_node_update_key(struct btree_trans *, struct btree_iter *,
 			       struct btree *, struct bkey_i *,
diff --git a/fs/bcachefs/errcode.h b/fs/bcachefs/errcode.h
index 4590cd0c7c90..712877036612 100644
--- a/fs/bcachefs/errcode.h
+++ b/fs/bcachefs/errcode.h
@@ -119,6 +119,7 @@
 	x(ENOENT,			ENOENT_dev_idx_not_found)		\
 	x(ENOENT,			ENOENT_inode_no_backpointer)		\
 	x(ENOENT,			ENOENT_no_snapshot_tree_subvol)		\
+	x(ENOENT,			btree_node_dying)			\
 	x(ENOTEMPTY,			ENOTEMPTY_dir_not_empty)		\
 	x(ENOTEMPTY,			ENOTEMPTY_subvol_not_empty)		\
 	x(EEXIST,			EEXIST_str_hash_set)			\