Messages in this thread Patch in this message | | | From | Arnd Bergmann <> | Date | Wed, 13 Nov 2019 09:06:57 +0100 | Subject | Re: [Y2038] [PATCH 13/16] hfs/hfsplus: use 64-bit inode timestamps |
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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) }
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