From: "Arnd Bergmann" <arnd@arndb.de>
To: "Bibo Mao" <maobibo@loongson.cn>,
"Huacai Chen" <chenhuacai@loongson.cn>,
"Huacai Chen" <chenhuacai@kernel.org>
Cc: loongarch@lists.linux.dev,
Linux-Arch <linux-arch@vger.kernel.org>,
"Xuefeng Li" <lixuefeng@loongson.cn>, guoren <guoren@kernel.org>,
"WANG Xuerui" <kernel@xen0n.name>,
"Jiaxun Yang" <jiaxun.yang@flygoat.com>,
linux-kernel@vger.kernel.org, loongson-kernel@lists.loongnix.cn,
stable@vger.kernel.org
Subject: Re: [PATCH] LoongArch: Define __ARCH_WANT_NEW_STAT in unistd.h
Date: Wed, 15 May 2024 14:25:28 +0000 [thread overview]
Message-ID: <ebf493ee-1e8b-426d-bcf4-d8e17d10844a@app.fastmail.com> (raw)
In-Reply-To: <3937d6b1-119b-195e-8b9b-314a0bfbeaeb@loongson.cn>
On Wed, May 15, 2024, at 09:30, maobibo wrote:
> On 2024/5/11 下午8:17, Arnd Bergmann wrote:
>> On Sat, May 11, 2024, at 12:01, Huacai Chen wrote:
>>
>> Importantly, we can't just add fstatat64() on riscv32 because
>> there is no time64 version for it other than statx(), and I don't
>> want the architectures to diverge more than necessary.
> yes, I agree. Normally there is newfstatat() on 64-bit architectures but
> fstatat64() on 32-bit ones.
>
> I do not understand why fstatat64() can be added for riscv32 still.
> 32bit timestamp seems works well for the present, it is valid until
> (0x1UL << 32) / 365 / 24 / 3600 + 1970 == 2106 year. Year 2106 should
> be enough for 32bit system.
There is a very small number of interfaces for which we ended up
not using a 64-bit time_t replacement, but those are only for
relative times, not epoch based offsets. The main problems
here are:
- time_t is defined to be a signed value in posix, and we need
to handle file timestamps before 1970 in stat(), so changing
this one to be unsigned is not an option.
- A lot of products have already shipped that will have to
be supported past 2038 on existing 32-bit hardware. We
cannot regress on architectures that have already been
fixed to support this.
- file timestamps can also be set into the future, so applications
relying on this are broken before 2038.
Arnd
next prev parent reply other threads:[~2024-05-15 14:25 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-11 10:01 [PATCH] LoongArch: Define __ARCH_WANT_NEW_STAT in unistd.h Huacai Chen
2024-05-11 12:17 ` Arnd Bergmann
2024-05-11 14:28 ` Huacai Chen
2024-05-11 15:38 ` Arnd Bergmann
2024-05-12 3:11 ` Huacai Chen
2024-05-12 7:52 ` Arnd Bergmann
2024-05-15 9:30 ` maobibo
2024-05-15 14:25 ` Arnd Bergmann [this message]
2024-05-16 2:52 ` maobibo
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