linux-kernel - Re: [PATCH v3 5/9] iomap: drop the write failure handles when unsharing and zeroing

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Date: Tue, 19 Mar 2024 14:03:42 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: Zhang Yi <yi.zhang@...weicloud.com>
Cc: linux-xfs@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org, hch@...radead.org, brauner@...nel.org,
	david@...morbit.com, tytso@....edu, jack@...e.cz,
	yi.zhang@...wei.com, chengzhihao1@...wei.com, yukuai3@...wei.com
Subject: Re: [PATCH v3 5/9] iomap: drop the write failure handles when
 unsharing and zeroing

On Tue, Mar 19, 2024 at 09:10:58AM +0800, Zhang Yi wrote:
> From: Zhang Yi <yi.zhang@...wei.com>
> 
> Unsharing and zeroing can only happen within EOF, so there is never a
> need to perform posteof pagecache truncation if write begin fails, also
> partial write could never theoretically happened from iomap_write_end(),
> so remove both of them.
> 
> Signed-off-by: Zhang Yi <yi.zhang@...wei.com>
> Reviewed-by: Christoph Hellwig <hch@....de>

Makes sense,
Reviewed-by: Darrick J. Wong <djwong@...nel.org>

--D

> ---
>  fs/iomap/buffered-io.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 093c4515b22a..7e32a204650b 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -786,7 +786,6 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos,
>  
>  out_unlock:
>  	__iomap_put_folio(iter, pos, 0, folio);
> -	iomap_write_failed(iter->inode, pos, len);
>  
>  	return status;
>  }
> @@ -863,8 +862,6 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
>  
>  	if (old_size < pos)
>  		pagecache_isize_extended(iter->inode, old_size, pos);
> -	if (ret < len)
> -		iomap_write_failed(iter->inode, pos + ret, len - ret);
>  	return ret;
>  }
>  
> @@ -912,8 +909,10 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
>  		}
>  
>  		status = iomap_write_begin(iter, pos, bytes, &folio);
> -		if (unlikely(status))
> +		if (unlikely(status)) {
> +			iomap_write_failed(iter->inode, pos, bytes);
>  			break;
> +		}
>  		if (iter->iomap.flags & IOMAP_F_STALE)
>  			break;
>  
> @@ -927,6 +926,9 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
>  		copied = copy_folio_from_iter_atomic(folio, offset, bytes, i);
>  		status = iomap_write_end(iter, pos, bytes, copied, folio);
>  
> +		if (status < bytes)
> +			iomap_write_failed(iter->inode, pos + status,
> +					   bytes - status);
>  		if (unlikely(copied != status))
>  			iov_iter_revert(i, copied - status);
>  
> -- 
> 2.39.2
> 
>