Re: [PATCH 10/20] ext4: get rid of ppath in ext4_ext_create_new_leaf()

[Baokun Li]

On 2024/7/25 18:46, Jan Kara wrote:
> On Wed 10-07-24 12:06:44, libaokun@xxxxxxxxxxxxxxx wrote:
> > From: Baokun Li <libaokun1@xxxxxxxxxx>
> >
> > The use of path and ppath is now very confusing, so to make the code more
> > readable, pass path between functions uniformly, and get rid of ppath.
> >
> > To get rid of the ppath in ext4_ext_create_new_leaf(), the following is
> > done here:
> >
> >   * Free the extents path when an error is encountered.
> >   * Its caller needs to update ppath if it uses ppath.
> >
> > No functional changes.
> >
> > Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
> Just one nit below. Otherwise feel free to add:
>
> Reviewed-by: Jan Kara <jack@xxxxxxx>
>
> > @@ -1424,28 +1423,24 @@ static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
> >   		 * entry: create all needed subtree and add new leaf */
> >   		err = ext4_ext_split(handle, inode, mb_flags, path, newext, i);
> >   		if (err)
> > -			goto out;
> > +			goto errout;
> >   
> >   		/* refill path */
> >   		path = ext4_find_extent(inode,
> >   				    (ext4_lblk_t)le32_to_cpu(newext->ee_block),
> >   				    path, gb_flags);
> > -		if (IS_ERR(path))
> > -			err = PTR_ERR(path);
> So I'd rather have here:
> 		return path;
>
> That way it's obvious we will not confuse some code below with error stored
> in 'path' and we can also save one indentation level by removing 'else'
> below (probably do reindenting in a separate patch).
>
> 								Honza
Yes, that looks clearer! I'll add 'return path' in the next version, and
add a cleanup patch after this one to save indentation.

Thanks,
Baokun
> >   	} else {
> >   		/* tree is full, time to grow in depth */
> >   		err = ext4_ext_grow_indepth(handle, inode, mb_flags);
> >   		if (err)
> > -			goto out;
> > +			goto errout;
> >   
> >   		/* refill path */
> >   		path = ext4_find_extent(inode,
> >   				   (ext4_lblk_t)le32_to_cpu(newext->ee_block),
> >   				    path, gb_flags);
> > -		if (IS_ERR(path)) {
> > -			err = PTR_ERR(path);
> > -			goto out;
> > -		}
> > +		if (IS_ERR(path))
> > +			return path;
> >   
> >   		/*
> >   		 * only first (depth 0 -> 1) produces free space;
> > @@ -1457,9 +1452,11 @@ static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
> >   			goto repeat;
> >   		}
> >   	}
> > -out:
> > -	*ppath = IS_ERR(path) ? NULL : path;
> > -	return err;
> > +	return path;
> > +
> > +errout:
> > +	ext4_free_ext_path(path);
> > +	return ERR_PTR(err);
> >   }
> >   
> >   /*
> > @@ -2112,10 +2109,14 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
> >   	 */
> >   	if (gb_flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
> >   		mb_flags |= EXT4_MB_USE_RESERVED;
> > -	err = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
> > -				       ppath, newext);
> > -	if (err)
> > +	path = ext4_ext_create_new_leaf(handle, inode, mb_flags, gb_flags,
> > +					path, newext);
> > +	if (IS_ERR(path)) {
> > +		*ppath = NULL;
> > +		err = PTR_ERR(path);
> >   		goto cleanup;
> > +	}
> > +	*ppath = path;
> >   	depth = ext_depth(inode);
> >   	eh = path[depth].p_hdr;
> >   
> > --
> > 2.39.2
--
With Best Regards,
Baokun Li