RE: [PATCH v9 02/13] exfat: add super block operations

[Namjae Jeon]

> Looks good, modulo a few nitpicks below:
> 
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Thanks!
> 
> On Thu, Jan 02, 2020 at 04:20:25PM +0800, Namjae Jeon wrote:
> > +static int exfat_statfs(struct dentry *dentry, struct kstatfs *buf) {
> > +	struct super_block *sb = dentry->d_sb;
> > +	struct exfat_sb_info *sbi = EXFAT_SB(sb);
> > +	unsigned long long id = huge_encode_dev(sb->s_bdev->bd_dev);
> 
> > +	if (sbi->used_clusters == ~0u) {
> 
> Various other places use UINT_MAX here instead.  Maybe it makes sense to
> add a EXFAT_CLUSTERS_UNTRACKED or similar define and use that in all
> places?
Okay.
> 
> > +	if ((new_flag == VOL_DIRTY) && (!buffer_dirty(sbi->pbr_bh)))
> 
> No need for both sets of inner braces.
Yep.
> 
> > +static bool is_exfat(struct pbr *pbr) {
> > +	int i = MUST_BE_ZERO_LEN;
> > +
> > +	do {
> > +		if (pbr->bpb.f64.res_zero[i - 1])
> > +			break;
> > +	} while (--i);
> > +	return i ? false : true;
> > +}
> 
> I find the MUST_BE_ZERO_LEN a little weird here.  Maybe that should be
> something like PBP64_RESERVED_LEN?
Okay.

> 
> Also I think this could be simplified by just using memchr_inv in the
> caller
> 
> 	if (memchr_inv(pbr->bpb.f64.res_zero, 0,
> 			sizeof(pbr->bpb.f64.res_zero)))
> 		ret = -EINVAL;
> 		goto free_bh;
> 	}
Okay.
> 
> > +	/* set maximum file size for exFAT */
> > +	sb->s_maxbytes = 0x7fffffffffffffffLL;
> 
> That this is setting the max size is pretty obvious.  Maybe the comment
> should be updated to mention how this max file size is calculated?
I will add the comment.

Thanks for your review!