linux-kernel - Re: [PATCH 1/9] iomap: Fix misplaced page flushing

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Message-ID: <20200825204753.GF6096@magnolia>
Date:   Tue, 25 Aug 2020 13:47:53 -0700
From:   "Darrick J. Wong" <darrick.wong@...cle.com>
To:     "Matthew Wilcox (Oracle)" <willy@...radead.org>
Cc:     linux-xfs@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-nvdimm@...ts.01.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/9] iomap: Fix misplaced page flushing

On Mon, Aug 24, 2020 at 03:55:02PM +0100, Matthew Wilcox (Oracle) wrote:
> If iomap_unshare_actor() unshares to an inline iomap, the page was
> not being flushed.  block_write_end() and __iomap_write_end() already
> contain flushes, so adding it to iomap_write_end_inline() seems like
> the best place.  That means we can remove it from iomap_write_actor().
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>

Seems reasonable to me...
Reviewed-by: Darrick J. Wong <darrick.wong@...cle.com>

--D

> ---
>  fs/iomap/buffered-io.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index bcfc288dba3f..cffd575e57b6 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -715,6 +715,7 @@ iomap_write_end_inline(struct inode *inode, struct page *page,
>  {
>  	void *addr;
>  
> +	flush_dcache_page(page);
>  	WARN_ON_ONCE(!PageUptodate(page));
>  	BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data));
>  
> @@ -811,8 +812,6 @@ iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
>  
>  		copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes);
>  
> -		flush_dcache_page(page);
> -
>  		status = iomap_write_end(inode, pos, bytes, copied, page, iomap,
>  				srcmap);
>  		if (unlikely(status < 0))
> -- 
> 2.28.0
>