Re: [PATCH v3 2/4] ext4: Check for atomic writes support in write iter

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Oct 30, 2024 at 09:27:39PM +0530, Ritesh Harjani (IBM) wrote:
> Let's validate the given constraints for atomic write request.
> Otherwise it will fail with -EINVAL. Currently atomic write is only
> supported on DIO, so for buffered-io it will return -EOPNOTSUPP.
> 
> Reviewed-by: John Garry <john.g.garry@oracle.com>
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>

Looks decent,
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D

> ---
>  fs/ext4/file.c | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
> 
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index f14aed14b9cf..a7b9b9751a3f 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -692,6 +692,20 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
>  	if (IS_DAX(inode))
>  		return ext4_dax_write_iter(iocb, from);
>  #endif
> +
> +	if (iocb->ki_flags & IOCB_ATOMIC) {
> +		size_t len = iov_iter_count(from);
> +		int ret;
> +
> +		if (len < EXT4_SB(inode->i_sb)->s_awu_min ||
> +		    len > EXT4_SB(inode->i_sb)->s_awu_max)
> +			return -EINVAL;
> +
> +		ret = generic_atomic_write_valid(iocb, from);
> +		if (ret)
> +			return ret;
> +	}
> +
>  	if (iocb->ki_flags & IOCB_DIRECT)
>  		return ext4_dio_write_iter(iocb, from);
>  	else
> -- 
> 2.46.0
> 
>