Re: [f2fs-dev] [PATCH] f2fs: ensure minimum trim granularity accounts for all devices

[Chao Yu via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net>]

On 10/24/25 22:37, Yongpeng Yang wrote:
> From: Yongpeng Yang <yangyongpeng@xiaomi.com>
> 
> When F2FS uses multiple block devices, each device may have a
> different discard granularity. The minimum trim granularity must be
> at least the maximum discard granularity of all devices, excluding
> zoned devices. Use max_t instead of the max() macro to compute the
> maximum value.
> 
> Signed-off-by: Yongpeng Yang <yangyongpeng@xiaomi.com>
> ---
>  fs/f2fs/f2fs.h | 12 ++++++++++++
>  fs/f2fs/file.c | 12 ++++++------
>  2 files changed, 18 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 32fb2e7338b7..064bdbf463f7 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -4762,6 +4762,18 @@ static inline bool f2fs_hw_support_discard(struct f2fs_sb_info *sbi)
>  	return false;
>  }
>  
> +static inline unsigned int f2fs_hw_discard_granularity(struct f2fs_sb_info *sbi)
> +{
> +	int i = 1;
> +	unsigned int discard_granularity = bdev_discard_granularity(sbi->sb->s_bdev);

Yongpeng,

The patch makes sense to me.

One extra question, if a zoned device contains both conventional zones and
sequential zones, what discard granularity will it exposes?

Thanks,

> +
> +	if (f2fs_is_multi_device(sbi))
> +		for (; i < sbi->s_ndevs && !bdev_is_zoned(FDEV(i).bdev); i++)
> +			discard_granularity = max_t(unsigned int, discard_granularity,
> +						bdev_discard_granularity(FDEV(i).bdev));
> +	return discard_granularity;
> +}
> +
>  static inline bool f2fs_realtime_discard_enable(struct f2fs_sb_info *sbi)
>  {
>  	return (test_opt(sbi, DISCARD) && f2fs_hw_support_discard(sbi)) ||
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index 6d42e2d28861..ced0f78532c9 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -2588,14 +2588,14 @@ static int f2fs_keep_noreuse_range(struct inode *inode,
>  static int f2fs_ioc_fitrim(struct file *filp, unsigned long arg)
>  {
>  	struct inode *inode = file_inode(filp);
> -	struct super_block *sb = inode->i_sb;
> +	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>  	struct fstrim_range range;
>  	int ret;
>  
>  	if (!capable(CAP_SYS_ADMIN))
>  		return -EPERM;
>  
> -	if (!f2fs_hw_support_discard(F2FS_SB(sb)))
> +	if (!f2fs_hw_support_discard(sbi))
>  		return -EOPNOTSUPP;
>  
>  	if (copy_from_user(&range, (struct fstrim_range __user *)arg,
> @@ -2606,9 +2606,9 @@ static int f2fs_ioc_fitrim(struct file *filp, unsigned long arg)
>  	if (ret)
>  		return ret;
>  
> -	range.minlen = max((unsigned int)range.minlen,
> -			   bdev_discard_granularity(sb->s_bdev));
> -	ret = f2fs_trim_fs(F2FS_SB(sb), &range);
> +	range.minlen = max_t(unsigned int, range.minlen,
> +			f2fs_hw_discard_granularity(sbi));
> +	ret = f2fs_trim_fs(sbi, &range);
>  	mnt_drop_write_file(filp);
>  	if (ret < 0)
>  		return ret;
> @@ -2616,7 +2616,7 @@ static int f2fs_ioc_fitrim(struct file *filp, unsigned long arg)
>  	if (copy_to_user((struct fstrim_range __user *)arg, &range,
>  				sizeof(range)))
>  		return -EFAULT;
> -	f2fs_update_time(F2FS_I_SB(inode), REQ_TIME);
> +	f2fs_update_time(sbi, REQ_TIME);
>  	return 0;
>  }
>  



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