Re: [PATCH v3 01/13] btrfs: add sysfs interface for supported sectorsize

[Anand Jain <anandsuveer@gmail.com>]

On 25/03/2021 15:14, Qu Wenruo wrote:
> Add extra sysfs interface features/supported_ro_sectorsize and
> features/supported_rw_sectorsize to indicate subpage support.
> 
> Currently for supported_rw_sectorsize all architectures only have their
> PAGE_SIZE listed.
> 
> While for supported_ro_sectorsize, for systems with 64K page size, 4K
> sectorsize is also supported.
> 

  Change-log does match with the changes below.

> This new sysfs interface would help mkfs.btrfs to do more accurate
> warning.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
>   fs/btrfs/sysfs.c | 15 +++++++++++++++
>   1 file changed, 15 insertions(+)
> 
> diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
> index 6eb1c50fa98c..2f9c2639707c 100644
> --- a/fs/btrfs/sysfs.c
> +++ b/fs/btrfs/sysfs.c
> @@ -360,11 +360,26 @@ static ssize_t supported_rescue_options_show(struct kobject *kobj,
>   BTRFS_ATTR(static_feature, supported_rescue_options,
>   	   supported_rescue_options_show);
>   
> +static ssize_t supported_sectorsizes_show(struct kobject *kobj,
> +					  struct kobj_attribute *a,
> +					  char *buf)
> +{
> +	ssize_t ret = 0;
> +
> +	/* Only support sectorsize == PAGE_SIZE yet */
> +	ret += scnprintf(buf + ret, PAGE_SIZE - ret, "%lu\n",
> +			 PAGE_SIZE);
> +	return ret;
> +}

   ret can be removed completely here.

Thanks, Anand


> +BTRFS_ATTR(static_feature, supported_sectorsizes,
> +	   supported_sectorsizes_show);
> +
>   static struct attribute *btrfs_supported_static_feature_attrs[] = {
>   	BTRFS_ATTR_PTR(static_feature, rmdir_subvol),
>   	BTRFS_ATTR_PTR(static_feature, supported_checksums),
>   	BTRFS_ATTR_PTR(static_feature, send_stream_version),
>   	BTRFS_ATTR_PTR(static_feature, supported_rescue_options),
> +	BTRFS_ATTR_PTR(static_feature, supported_sectorsizes),
>   	NULL
>   };
>   
>