btrfs: rename werr and err to ret in __btrfs_wait_marked_extents()

Rename the function's local return variables err and werr to ret.
Also, align the variable declarations with the other declarations in
the function for better function space alignment.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/transaction.c

@@ -1171,12 +1171,11 @@ int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
 static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
 				       struct extent_io_tree *dirty_pages)
 {
-	int err = 0;
-	int werr = 0;
 	struct address_space *mapping = fs_info->btree_inode->i_mapping;
 	struct extent_state *cached_state = NULL;
 	u64 start = 0;
 	u64 end;
+	int ret = 0;
 
 	while (find_first_extent_bit(dirty_pages, start, &start, &end,
 				     EXTENT_NEED_WAIT, &cached_state)) {
@@ -1188,24 +1187,20 @@ static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
 		 * concurrently - we do it only at transaction commit time when
 		 * it's safe to do it (through extent_io_tree_release()).
 		 */
-		err = clear_extent_bit(dirty_pages, start, end,
+		ret = clear_extent_bit(dirty_pages, start, end,
 				       EXTENT_NEED_WAIT, &cached_state);
-		if (err == -ENOMEM)
-			err = 0;
-		if (!err)
-			err = filemap_fdatawait_range(mapping, start, end);
-		if (err)
-			werr = err;
+		if (ret == -ENOMEM)
+			ret = 0;
+		if (!ret)
+			ret = filemap_fdatawait_range(mapping, start, end);
 		free_extent_state(cached_state);
-		if (werr)
+		if (ret)
 			break;
 		cached_state = NULL;
 		cond_resched();
 		start = end + 1;
 	}
-	if (err)
-		werr = err;
-	return werr;
+	return ret;
 }
 
 static int btrfs_wait_extents(struct btrfs_fs_info *fs_info,