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Message-ID: <fff201b0d21a8ba775eb1d201e083ba96f8ff6f1.camel@codethink.co.uk>
Subject: Re: [Y2038] [PATCH 12/16] hostfs: pass 64-bit timestamps to/from
 user space
From:   Ben Hutchings <ben.hutchings@codethink.co.uk>
To:     Arnd Bergmann <arnd@arndb.de>, y2038@lists.linaro.org,
        Jeff Dike <jdike@addtoit.com>,
        Richard Weinberger <richard@nod.at>,
        Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc:     Colin Ian King <colin.king@canonical.com>,
        linux-um@lists.infradead.org, linux-kernel@vger.kernel.org,
        Al Viro <viro@zeniv.linux.org.uk>
Date:   Wed, 20 Nov 2019 20:30:22 +0000
In-Reply-To: <20191108213257.3097633-13-arnd@arndb.de>
References: <20191108213257.3097633-1-arnd@arndb.de>
         <20191108213257.3097633-13-arnd@arndb.de>
Organization: Codethink Ltd.
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On Fri, 2019-11-08 at 22:32 +0100, Arnd Bergmann wrote:
> The use of 'struct timespec' is deprecated in the kernel, so we
> want to avoid the conversions from/to the proper timespec64
> structure.
> 
> On the user space side, we have a 'struct timespec' that is defined
> by the C library and that will be incompatible with the kernel's
> view on 32-bit architectures once they move to a 64-bit time_t,
> breaking the shared binary layout of hostfs_iattr and hostfs_stat.
> 
> This changes the two structures to use a new hostfs_timespec structure
> with fixed 64-bit seconds/nanoseconds for passing the timestamps
> between hostfs_kern.c and hostfs_user.c. With a new enough user
> space side, this will allow timestamps beyond year 2038.
[...]

The "user-space" side has a structure assignment in set_attr():

	if (attrs->ia_valid & (HOSTFS_ATTR_ATIME | HOSTFS_ATTR_MTIME)) {
		err = stat_file(file, &st, fd);
		attrs->ia_atime = st.atime;
		attrs->ia_mtime = st.mtime;
		if (err != 0)
			return err;
	}

which will also need to be updated for this type change.

Ben.

-- 
Ben Hutchings, Software Developer                         Codethink Ltd
https://www.codethink.co.uk/                 Dale House, 35 Dale Street
                                     Manchester, M1 2HF, United Kingdom