btrfs: use label to deduplicate error path at btrfs_force_cow_block()

Commit Message

Filipe Manana June 17, 2024, 11:24 a.m. UTC

From: Filipe Manana <[e-mail]>

At btrfs_force_cow_block() we have several error paths that need to
unlock the "cow" extent buffer, drop the reference on it and then return
an error. This is a bit verbose so add a label where we perform these
tasks and make the error paths jump to that label.

Signed-off-by: Filipe Manana <[e-mail]>
---
 fs/btrfs/ctree.c | 33 ++++++++++++---------------------
 1 file changed, 12 insertions(+), 21 deletions(-)

Comments

David Sterba June 17, 2024, 2 p.m. UTC | #1

On Mon, Jun 17, 2024 at 12:24:03PM +0100, [e-mail] wrote:
> From: Filipe Manana <[e-mail]>
> 
> At btrfs_force_cow_block() we have several error paths that need to
> unlock the "cow" extent buffer, drop the reference on it and then return
> an error. This is a bit verbose so add a label where we perform these
> tasks and make the error paths jump to that label.
> 
> Signed-off-by: Filipe Manana <[e-mail]>

Reviewed-by: David Sterba <[e-mail]>

Patch

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index a155dbc0bffa..763b9a1da428 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -588,19 +588,15 @@  int btrfs_force_cow_block(struct btrfs_trans_handle *trans,
 
 	ret = update_ref_for_cow(trans, root, buf, cow, &last_ref);
 	if (ret) {
-		btrfs_tree_unlock(cow);
-		free_extent_buffer(cow);
 		btrfs_abort_transaction(trans, ret);
-		return ret;
+		goto error_unlock_cow;
 	}
 
 	if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
 		ret = btrfs_reloc_cow_block(trans, root, buf, cow);
 		if (ret) {
-			btrfs_tree_unlock(cow);
-			free_extent_buffer(cow);
 			btrfs_abort_transaction(trans, ret);
-			return ret;
+			goto error_unlock_cow;
 		}
 	}
 
@@ -612,10 +608,8 @@  int btrfs_force_cow_block(struct btrfs_trans_handle *trans,
 
 		ret = btrfs_tree_mod_log_insert_root(root->node, cow, true);
 		if (ret < 0) {
-			btrfs_tree_unlock(cow);
-			free_extent_buffer(cow);
 			btrfs_abort_transaction(trans, ret);
-			return ret;
+			goto error_unlock_cow;
 		}
 		atomic_inc(&cow->refs);
 		rcu_assign_pointer(root->node, cow);
@@ -625,20 +619,16 @@  int btrfs_force_cow_block(struct btrfs_trans_handle *trans,
 		free_extent_buffer(buf);
 		add_root_to_dirty_list(root);
 		if (ret < 0) {
-			btrfs_tree_unlock(cow);
-			free_extent_buffer(cow);
 			btrfs_abort_transaction(trans, ret);
-			return ret;
+			goto error_unlock_cow;
 		}
 	} else {
 		WARN_ON(trans->transid != btrfs_header_generation(parent));
 		ret = btrfs_tree_mod_log_insert_key(parent, parent_slot,
 						    BTRFS_MOD_LOG_KEY_REPLACE);
 		if (ret) {
-			btrfs_tree_unlock(cow);
-			free_extent_buffer(cow);
 			btrfs_abort_transaction(trans, ret);
-			return ret;
+			goto error_unlock_cow;
 		}
 		btrfs_set_node_blockptr(parent, parent_slot,
 					cow->start);
@@ -648,19 +638,15 @@  int btrfs_force_cow_block(struct btrfs_trans_handle *trans,
 		if (last_ref) {
 			ret = btrfs_tree_mod_log_free_eb(buf);
 			if (ret) {
-				btrfs_tree_unlock(cow);
-				free_extent_buffer(cow);
 				btrfs_abort_transaction(trans, ret);
-				return ret;
+				goto error_unlock_cow;
 			}
 		}
 		ret = btrfs_free_tree_block(trans, btrfs_root_id(root), buf,
 					    parent_start, last_ref);
 		if (ret < 0) {
-			btrfs_tree_unlock(cow);
-			free_extent_buffer(cow);
 			btrfs_abort_transaction(trans, ret);
-			return ret;
+			goto error_unlock_cow;
 		}
 	}
 	if (unlock_orig)
@@ -669,6 +655,11 @@  int btrfs_force_cow_block(struct btrfs_trans_handle *trans,
 	btrfs_mark_buffer_dirty(trans, cow);
 	*cow_ret = cow;
 	return 0;
+
+error_unlock_cow:
+	btrfs_tree_unlock(cow);
+	free_extent_buffer(cow);
+	return ret;
 }
 
 static inline int should_cow_block(struct btrfs_trans_handle *trans,