linux-ext4 - Re: [PATCH] ext4: Convert ext4_da_do_write

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Date: Thu, 4 Jan 2024 17:41:45 +0100
From: Jan Kara <jack@...e.cz>
To: "Matthew Wilcox (Oracle)" <willy@...radead.org>
Cc: Theodore Ts'o <tytso@....edu>,
	Andreas Dilger <adilger.kernel@...ger.ca>,
	linux-ext4@...r.kernel.org
Subject: Re: [PATCH] ext4: Convert ext4_da_do_write_end() to take a folio

On Thu 14-12-23 05:30:35, Matthew Wilcox (Oracle) wrote:
> There's nothing page-specific happening in ext4_da_do_write_end();
> it's merely used for its refcount & lock, both of which are folio
> properties.  Saves four calls to compound_head().
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza

> ---
>  fs/ext4/inode.c | 19 ++++++++++---------
>  1 file changed, 10 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 83ee4e0f46f4..216ad9bcca45 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -2947,7 +2947,7 @@ static int ext4_da_should_update_i_disksize(struct folio *folio,
>  
>  static int ext4_da_do_write_end(struct address_space *mapping,
>  			loff_t pos, unsigned len, unsigned copied,
> -			struct page *page)
> +			struct folio *folio)
>  {
>  	struct inode *inode = mapping->host;
>  	loff_t old_size = inode->i_size;
> @@ -2958,12 +2958,13 @@ static int ext4_da_do_write_end(struct address_space *mapping,
>  	 * block_write_end() will mark the inode as dirty with I_DIRTY_PAGES
>  	 * flag, which all that's needed to trigger page writeback.
>  	 */
> -	copied = block_write_end(NULL, mapping, pos, len, copied, page, NULL);
> +	copied = block_write_end(NULL, mapping, pos, len, copied,
> +			&folio->page, NULL);
>  	new_i_size = pos + copied;
>  
>  	/*
> -	 * It's important to update i_size while still holding page lock,
> -	 * because page writeout could otherwise come in and zero beyond
> +	 * It's important to update i_size while still holding folio lock,
> +	 * because folio writeout could otherwise come in and zero beyond
>  	 * i_size.
>  	 *
>  	 * Since we are holding inode lock, we are sure i_disksize <=
> @@ -2981,14 +2982,14 @@ static int ext4_da_do_write_end(struct address_space *mapping,
>  
>  		i_size_write(inode, new_i_size);
>  		end = (new_i_size - 1) & (PAGE_SIZE - 1);
> -		if (copied && ext4_da_should_update_i_disksize(page_folio(page), end)) {
> +		if (copied && ext4_da_should_update_i_disksize(folio, end)) {
>  			ext4_update_i_disksize(inode, new_i_size);
>  			disksize_changed = true;
>  		}
>  	}
>  
> -	unlock_page(page);
> -	put_page(page);
> +	folio_unlock(folio);
> +	folio_put(folio);
>  
>  	if (old_size < pos)
>  		pagecache_isize_extended(inode, old_size, pos);
> @@ -3027,10 +3028,10 @@ static int ext4_da_write_end(struct file *file,
>  		return ext4_write_inline_data_end(inode, pos, len, copied,
>  						  folio);
>  
> -	if (unlikely(copied < len) && !PageUptodate(page))
> +	if (unlikely(copied < len) && !folio_test_uptodate(folio))
>  		copied = 0;
>  
> -	return ext4_da_do_write_end(mapping, pos, len, copied, &folio->page);
> +	return ext4_da_do_write_end(mapping, pos, len, copied, folio);
>  }
>  
>  /*
> -- 
> 2.42.0
> 
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR