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From:   "Sungjong Seo" <sj1557.seo@samsung.com>
To:     "'Namjae Jeon'" <linkinjeon@kernel.org>,
        "'Chung-Chiang Cheng'" <cccheng@synology.com>
Cc:     <linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <shepjeng@gmail.com>, <sj1557.seo@samsung.com>
In-Reply-To: <CAKYAXd_1ys-xQ9HusgqSr5GHaP6R2pK4JswfZzoqZ=wTnwSiOw@mail.gmail.com>
Subject: RE: [PATCH] exfat: use local UTC offset when EXFAT_TZ_VALID isn't
 set
Date:   Fri, 1 Oct 2021 22:19:07 +0900
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References: <20210909065543.164329-1-cccheng@synology.com>
        <CGME20210910010035epcas1p496dd515369b9f2481ccd1c0de5904bbd@epcas1p4.samsung.com>
        <CAKYAXd_1ys-xQ9HusgqSr5GHaP6R2pK4JswfZzoqZ=wTnwSiOw@mail.gmail.com>
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Hello, Namjae,

I found an important difference between the code we first wrote and the cod=
e that has changed since our initial patch review. This difference seems to=
 cause compatibility issues when reading saved timestamps without timezone.=
 (In our initial patch review, there were concerns about possible compatibi=
lity issues.)
I think the code that reads timestamps without timezone should go back to t=
he concept we wrote in the first place like reported patch.
It could be an answer of another timestamp issue.

Could you please let me know what you think?

Thanks.
> -----Original Message-----
> From: Namjae Jeon =5Bmailto:linkinjeon=40kernel.org=5D
> Sent: Friday, September 10, 2021 10:01 AM
> To: Chung-Chiang Cheng <cccheng=40synology.com>
> Cc: sj1557.seo=40samsung.com; linux-fsdevel=40vger.kernel.org; linux-
> kernel=40vger.kernel.org; shepjeng=40gmail.com
> Subject: Re: =5BPATCH=5D exfat: use local UTC offset when EXFAT_TZ_VALID =
isn't
> set
>=20
> 2021-09-09 15:55 GMT+09:00, Chung-Chiang Cheng <cccheng=40synology.com>:
> > EXFAT_TZ_VALID is corresponding to OffsetValid field in exfat
> > specification =5B1=5D. If this bit isn't set, timestamps should be trea=
ted
> > as having the same UTC offset as the current local time.
> >
> > This patch uses the existing mount option 'time_offset' as fat does.
> > If time_offset isn't set, local UTC offset in sys_tz will be used as
> > the default value.
> >
> > Link: =5B1=5D
> > https://protect2.fireeye.com/v1/url?k=3Dcba4edf5-943fd4c8-cba566ba-0cc4=
7
> > a31309a-e70aa065be678729&q=3D1&e=3D225feff2-841f-404c-9a2e-c12064b232d0=
&u=3D
> > https%3A%2F%2Fdocs.microsoft.com%2Fen-us%2Fwindows%2Fwin32%2Ffileio%2F
> > exfat-specification%2374102-offsetvalid-field
> > Signed-off-by: Chung-Chiang Cheng <cccheng=40synology.com>
> Please read this discussion:
>  https://patchwork.kernel.org/project/linux-
> fsdevel/patch/20200115082447.19520-10-namjae.jeon=40samsung.com/
>=20
> Thanks=21