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From:   "Sungjong Seo" <sj1557.seo@samsung.com>
To:     "'Tetsuhiro Kohada'" <kohada.t2@gmail.com>
Cc:     <kohada.tetsuhiro@dc.mitsubishielectric.co.jp>,
        <mori.takahiro@ab.mitsubishielectric.co.jp>,
        <motai.hirotaka@aj.mitsubishielectric.co.jp>,
        "'Namjae Jeon'" <namjae.jeon@samsung.com>,
        <linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>
In-Reply-To: <0f9d3d3e-075f-511d-12e5-21346bca081e@gmail.com>
Subject: RE: [PATCH] exfat: remove 'rwoffset' in exfat_inode_info
Date:   Fri, 25 Sep 2020 09:56:43 +0900
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> On 2020/09/12 14:01, Sungjong Seo wrote:
> >> Remove 'rwoffset' in exfat_inode_info and replace it with the
> >> parameter(cpos) of exfat_readdir.
> >> Since rwoffset of  is referenced only by exfat_readdir, it is not
> >> necessary a exfat_inode_info's member.
> >>
> >> Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
> >> ---
> >>   fs/exfat/dir.c      | 16 ++++++----------
> >>   fs/exfat/exfat_fs.h |  2 --
> >>   fs/exfat/file.c     |  2 --
> >>   fs/exfat/inode.c    |  3 ---
> >>   fs/exfat/super.c    |  1 -
> >>   5 files changed, 6 insertions(+), 18 deletions(-)
> >>
> >> diff --git a/fs/exfat/dir.c b/fs/exfat/dir.c index
> >> a9b13ae3f325..fa5bb72aa295 100644
> >> --- a/fs/exfat/dir.c
> >> +++ b/fs/exfat/dir.c
> > [snip]
> >> sector @@ -262,13 +260,11 @@ static int exfat_iterate(struct file
> >> *filp, struct dir_context *ctx)
> >>   		goto end_of_dir;
> >>   	}
> >>
> >> -	cpos = EXFAT_DEN_TO_B(ei->rwoffset);
> >> -
> >>   	if (!nb->lfn[0])
> >>   		goto end_of_dir;
> >>
> >>   	i_pos = ((loff_t)ei->start_clu << 32) |
> >> -		((ei->rwoffset - 1) & 0xffffffff);
> >> +		(EXFAT_B_TO_DEN(cpos-1) & 0xffffffff);
> >
> > Need to fix the above line to be:
> > (EXFAT_B_TO_DEN(cpos)-1)) & 0xffffffff);
> 
> 
> Here, we simply converted so that the calculation results would be the
> same.
> But after reading it carefully again, I noticed.
>   - Why use the previous entry?
>   - Why does cpos point to stream dir-entry in entry-set?
> 
> For the former, there is no need to "++dentry" in exfat_readdir().
> For the latter, I think cpos should point to the next to current entry-set.
> 
> I'll make V2 considering these.
> How do you think?

The latter looks better.
> 
> BR
> ---
> Tetsuhiro Kohada <kohada.t2@gmail.com>