Re: [PATCH] ext4: set awu_max_opt to awu_max

[Ritesh Harjani (IBM) <ritesh.list@gmail.com>]

Pankaj Raghav <p.raghav@samsung.com> writes:

> commit 5d894321c49e ("fs: add atomic write unit max opt to statx")
> added atomic write max optimal to statx. As XFS can support large atomic
> writes through SW, max_opt exposes the value that will be HW accelerated
> atomics.
>
> As ext4 does not support SW atomics, set awu_max_opt to awu_max.
>

As per the man page the awu_max_opt=0 means:

    A value of zero indicates that stx_atomic_write_unit_max is the
    optimised limit.

[1]: https://man7.org/linux/man-pages/man2/statx.2.html

But the value of 0 isn't wrong either. Jan, added that it might be more
clear to report awu_max there instead of 0. So, if are going to do it -
let's add this info to the commit msg. So it doesn't look like we were
trying to fix anything here ;)

btw note that bdev_statx() still reports 0 for awu_max_opt.

With that please feel free to add:

Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>

> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com>
> ---
>  fs/ext4/inode.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 26f0f9714f03..93056c971e74 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -6304,7 +6304,8 @@ int ext4_getattr(struct mnt_idmap *idmap, const struct path *path,
>  			awu_max = sbi->s_awu_max;
>  		}
>  
> -		generic_fill_statx_atomic_writes(stat, awu_min, awu_max, 0);
> +		generic_fill_statx_atomic_writes(stat, awu_min, awu_max,
> +						 awu_max);
>  	}
>  
>  	flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
>
> base-commit: d5ba62a0b130441bcabca59c2fd2d59e65360234
> -- 
> 2.51.2