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

[Jaegeuk Kim <jaegeuk@kernel.org>]

On 03/05, Chao Yu wrote:
> 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?

Or, adding a sysfs entry like "carve_out" to determine this?

> 
> 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;
>