From: Arnd Bergmann <arnd@arndb.de>
To: Viacheslav Dubeyko <slava@dubeyko.com>
Cc: "y2038 Mailman List" <y2038@lists.linaro.org>,
"Linux FS-devel Mailing List" <linux-fsdevel@vger.kernel.org>,
"Ernesto A. Fernández" <ernesto.mnd.fernandez@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>
Subject: Re: [Y2038] [PATCH 13/16] hfs/hfsplus: use 64-bit inode timestamps
Date: Wed, 13 Nov 2019 09:06:57 +0100 [thread overview]
Message-ID: <CAK8P3a1Bvdb4Xn1Aqfnxnn24HPb6FXxAAVwq8ypO31AqoR1hBw@mail.gmail.com> (raw)
In-Reply-To: <2520E708-4636-4CA8-B953-0F46F8E7454A@dubeyko.com>
On Wed, Nov 13, 2019 at 7:00 AM Viacheslav Dubeyko <slava@dubeyko.com> wrote:
> > On Nov 9, 2019, at 12:32 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> > * There are two time systems. Both are based on seconds since
> > * a particular time/date.
> > - * Unix: unsigned lil-endian since 00:00 GMT, Jan. 1, 1970
> > + * Unix: signed little-endian since 00:00 GMT, Jan. 1, 1970
> > * mac: unsigned big-endian since 00:00 GMT, Jan. 1, 1904
> > *
> > + * HFS implementations are highly inconsistent, this one matches the
> > + * traditional behavior of 64-bit Linux, giving the most useful
> > + * time range between 1970 and 2106, by treating any on-disk timestamp
> > + * under 2082844800U (Jan 1 1970) as a time between 2040 and 2106.
> > */
> > -#define __hfs_u_to_mtime(sec) cpu_to_be32(sec + 2082844800U - sys_tz.tz_minuteswest * 60)
> > -#define __hfs_m_to_utime(sec) (be32_to_cpu(sec) - 2082844800U + sys_tz.tz_minuteswest * 60)
>
> I believe it makes sense to introduce some constant instead of hardcoded value (2082844800U and 60).
> It will be easier to understand the code without necessity to take a look into the comments.
> What do you think?
Every other user of sys_tz.tz_minuteswest uses a plain '60', I think that one
is easy enough to understand from context. Naming the other constant
is a good idea, I've now folded the change below into my patch.
Thanks for the review!
Arnd
8<-----
diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h
index 26733051ee50..f71c384064c8 100644
--- a/fs/hfs/hfs_fs.h
+++ b/fs/hfs/hfs_fs.h
@@ -247,22 +247,24 @@ extern void hfs_mark_mdb_dirty(struct super_block *sb);
*
* HFS implementations are highly inconsistent, this one matches the
* traditional behavior of 64-bit Linux, giving the most useful
* time range between 1970 and 2106, by treating any on-disk timestamp
- * under 2082844800U (Jan 1 1970) as a time between 2040 and 2106.
+ * under HFS_UTC_OFFSET (Jan 1 1970) as a time between 2040 and 2106.
*/
+#define HFS_UTC_OFFSET 2082844800U
+
static inline time64_t __hfs_m_to_utime(__be32 mt)
{
- time64_t ut = (u32)(be32_to_cpu(mt) - 2082844800U);
+ time64_t ut = (u32)(be32_to_cpu(mt) - HFS_UTC_OFFSET);
return ut + sys_tz.tz_minuteswest * 60;
}
static inline __be32 __hfs_u_to_mtime(time64_t ut)
{
ut -= sys_tz.tz_minuteswest * 60;
- return cpu_to_be32(lower_32_bits(ut) + 2082844800U);
+ return cpu_to_be32(lower_32_bits(ut) + HFS_UTC_OFFSET);
}
#define HFS_I(inode) (container_of(inode, struct hfs_inode_info, vfs_inode))
#define HFS_SB(sb) ((struct hfs_sb_info *)(sb)->s_fs_info)
diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index 22d0a22c41a3..3b03fff68543 100644
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -538,20 +538,22 @@ int hfsplus_read_wrapper(struct super_block *sb);
*
* HFS+ implementations are highly inconsistent, this one matches the
* traditional behavior of 64-bit Linux, giving the most useful
* time range between 1970 and 2106, by treating any on-disk timestamp
- * under 2082844800U (Jan 1 1970) as a time between 2040 and 2106.
+ * under HFSPLUS_UTC_OFFSET (Jan 1 1970) as a time between 2040 and 2106.
*/
+#define HFSPLUS_UTC_OFFSET 2082844800U
+
static inline time64_t __hfsp_mt2ut(__be32 mt)
{
- time64_t ut = (u32)(be32_to_cpu(mt) - 2082844800U);
+ time64_t ut = (u32)(be32_to_cpu(mt) - HFSPLUS_UTC_OFFSET);
return ut;
}
static inline __be32 __hfsp_ut2mt(time64_t ut)
{
- return cpu_to_be32(lower_32_bits(ut) + 2082844800U);
+ return cpu_to_be32(lower_32_bits(ut) + HFSPLUS_UTC_OFFSET);
}
/* compatibility */
#define hfsp_mt2ut(t) (struct timespec64){ .tv_sec = __hfsp_mt2ut(t) }
next prev parent reply other threads:[~2019-11-13 8:07 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-08 21:32 [PATCH 00/16] drivers: y2038 updates Arnd Bergmann
2019-11-08 21:32 ` [PATCH 01/16] staging: exfat: use prandom_u32() for i_generation Arnd Bergmann
2019-11-08 21:53 ` Valdis Klētnieks
2019-11-08 21:32 ` [PATCH 02/16] fat: " Arnd Bergmann
2019-11-08 21:32 ` [PATCH 03/16] net: sock: use __kernel_old_timespec instead of timespec Arnd Bergmann
2019-11-09 19:09 ` Deepa Dinamani
2019-11-08 21:32 ` [PATCH 04/16] dlm: use SO_SNDTIMEO_NEW instead of SO_SNDTIMEO_OLD Arnd Bergmann
2019-11-09 19:14 ` Deepa Dinamani
2019-11-08 21:32 ` [PATCH 05/16] xtensa: ISS: avoid struct timeval Arnd Bergmann
2019-11-08 21:38 ` Max Filippov
2019-11-08 21:32 ` [PATCH 06/16] um: ubd: use 64-bit time_t where possible Arnd Bergmann
2019-11-08 21:32 ` [PATCH 07/16] acct: stop using get_seconds() Arnd Bergmann
2019-11-08 21:32 ` [PATCH 08/16] tsacct: add 64-bit btime field Arnd Bergmann
2019-11-08 21:32 ` [PATCH 09/16] netfilter: nft_meta: use 64-bit time arithmetic Arnd Bergmann
2019-11-09 11:20 ` Phil Sutter
2019-11-15 22:44 ` Pablo Neira Ayuso
2019-11-08 21:32 ` [PATCH 10/16] packet: clarify timestamp overflow Arnd Bergmann
2019-11-08 21:32 ` [PATCH 11/16] quota: avoid time_t in v1_disk_dqblk definition Arnd Bergmann
2019-11-08 21:32 ` [PATCH 12/16] hostfs: pass 64-bit timestamps to/from user space Arnd Bergmann
2019-11-20 20:30 ` [Y2038] " Ben Hutchings
2019-11-20 20:35 ` Ben Hutchings
2019-11-08 21:32 ` [PATCH 13/16] hfs/hfsplus: use 64-bit inode timestamps Arnd Bergmann
2019-11-13 3:53 ` Ernesto A. Fernández
2019-11-13 5:59 ` Viacheslav Dubeyko
2019-11-13 8:06 ` Arnd Bergmann [this message]
2019-11-13 17:03 ` [Y2038] " Viacheslav Dubeyko
2019-11-08 21:32 ` [PATCH 14/16] drm/msm: avoid using 'timespec' Arnd Bergmann
2019-11-12 16:55 ` Jordan Crouse
2019-11-08 21:32 ` [PATCH 15/16] drm/etnaviv: use ktime_t for timeouts Arnd Bergmann
2019-11-08 23:03 ` Lucas Stach
2019-11-09 12:12 ` Arnd Bergmann
2019-11-11 9:55 ` Lucas Stach
2019-11-11 16:24 ` Arnd Bergmann
2019-11-08 21:32 ` [PATCH 16/16] firewire: ohci: stop using get_seconds() for BUS_TIME Arnd Bergmann
2019-11-13 20:04 ` Stefan Richter
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