Re: [f2fs-dev] [PATCH] f2fs: subtract current_reserved_blocks from total

[Chao Yu <chao@kernel.org>]

On 3/5/25 03:20, Daeho Jeong wrote:
> From: Daeho Jeong <daehojeong@google.com>
> 
> current_reserved_blocks is not allowed to utilize. For some zoned
> storage devices, vendors will provide extra space which was used for
> device level GC than specs and we will use this space for filesystem
> level GC. This extra space should not be shown to users, otherwise,
> users will see not standardized size number like 530GB, not 512GB.

Hi Daeho,

However, if there are other users e.g. oem or vendor want to use
reserved_blocks and current_reserved_blocks sysfs interface to
reserve space, then, total size will be less than 512GB?

What do you think of adding a new variable to indicate reserved
space for zoned storage case only?

Thanks,

> 
> Signed-off-by: Daeho Jeong <daehojeong@google.com>
> ---
>  fs/f2fs/super.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
> index 19b67828ae32..c346dcc2518a 100644
> --- a/fs/f2fs/super.c
> +++ b/fs/f2fs/super.c
> @@ -1833,10 +1833,9 @@ static int f2fs_statfs(struct dentry *dentry, struct kstatfs *buf)
>  	buf->f_type = F2FS_SUPER_MAGIC;
>  	buf->f_bsize = sbi->blocksize;
>  
> -	buf->f_blocks = total_count - start_count;
> -
>  	spin_lock(&sbi->stat_lock);
>  
> +	buf->f_blocks = total_count - start_count - sbi->current_reserved_blocks;
>  	user_block_count = sbi->user_block_count;
>  	total_valid_node_count = valid_node_count(sbi);
>  	avail_node_count = sbi->total_node_count - F2FS_RESERVED_NODE_NUM;