Re: [PATCH v2 4/4] ext4: Do not fallback to buffered-io for DIO atomic write

[John Garry <john.g.garry@oracle.com>]

On 27/10/2024 18:17, Ritesh Harjani (IBM) wrote:
> iomap can return -ENOTBLK if pagecache invalidation fails.
> Let's make sure if -ENOTBLK is ever returned for atomic
> writes than we fail the write request (-EIO) instead of
> fallback to buffered-io.
> 
> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>

I am not sure if you plan on dropping this patch...

> ---
>   fs/ext4/file.c | 12 +++++++++++-
>   1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index 8116bd78910b..22d31b4fdff3 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -576,8 +576,18 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
>   		iomap_ops = &ext4_iomap_overwrite_ops;
>   	ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
>   			   dio_flags, NULL, 0);
> -	if (ret == -ENOTBLK)
> +	if (ret == -ENOTBLK) {
>   		ret = 0;
> +		/*
> +		 * iomap can return -ENOTBLK if pagecache invalidation fails.
> +		 * Let's make sure if -ENOTBLK is ever returned for atomic
> +		 * writes than we fail the write request instead of fallback
> +		 * to buffered-io.
> +		 */
> +		if (iocb->ki_flags & IOCB_ATOMIC)
> +			ret = -EIO;
> +	}
> +
>   	if (extend) {
>   		/*
>   		 * We always perform extending DIO write synchronously so by
> --
> 2.46.0
>