linux-kernel - Re: [PATCH 02/17] writeback: also update wbc->nr_to

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Message-ID: <20231219173635.hrfs7snikfhcldre@quack3>
Date: Tue, 19 Dec 2023 18:36:35 +0100
From: Jan Kara <jack@...e.cz>
To: Christoph Hellwig <hch@....de>
Cc: linux-mm@...ck.org, "Matthew Wilcox (Oracle)" <willy@...radead.org>,
	Jan Kara <jack@...e.com>, David Howells <dhowells@...hat.com>,
	Brian Foster <bfoster@...hat.com>, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 02/17] writeback: also update wbc->nr_to_write on
 writeback failure

On Mon 18-12-23 16:35:38, Christoph Hellwig wrote:
> When exiting write_cache_pages early due to a non-integrity write
> failure, wbc->nr_to_write currently doesn't account for the folio
> we just failed to write.  This doesn't matter because the callers
> always ingore the value on a failure, but moving the update to
> common code will allow to simply the code, so do it.
			    ^^^ simplify

> Signed-off-by: Christoph Hellwig <hch@....de>

Otherwise the patch looks good. Feel free to add:

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

								Honza

> ---
>  mm/page-writeback.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index b13ea243edb6b2..8e312d73475646 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -2473,6 +2473,7 @@ int write_cache_pages(struct address_space *mapping,
>  			trace_wbc_writepage(wbc, inode_to_bdi(mapping->host));
>  			error = writepage(folio, wbc, data);
>  			nr = folio_nr_pages(folio);
> +			wbc->nr_to_write -= nr;
>  			if (unlikely(error)) {
>  				/*
>  				 * Handle errors according to the type of
> @@ -2506,7 +2507,6 @@ int write_cache_pages(struct address_space *mapping,
>  			 * we tagged for writeback prior to entering this loop.
>  			 */
>  			done_index = folio->index + nr;
> -			wbc->nr_to_write -= nr;
>  			if (wbc->nr_to_write <= 0 &&
>  			    wbc->sync_mode == WB_SYNC_NONE) {
>  				done = 1;
> -- 
> 2.39.2
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR