> On Nov 9, 2019, at 12:32 AM, Arnd Bergmann <arnd@xxxxxxxx> wrote: > > The interpretation of on-disk timestamps in HFS and HFS+ differs > between 32-bit and 64-bit kernels at the moment. Use 64-bit timestamps > consistently so apply the current 64-bit behavior everyhere. > > According to the official documentation for HFS+ [1], inode timestamps > are supposed to cover the time range from 1904 to 2040 as originally > used in classic MacOS. > > The traditional Linux usage is to convert the timestamps into an unsigned > 32-bit number based on the Unix epoch and from there to a time_t. On > 32-bit systems, that wraps the time from 2038 to 1902, so the last > two years of the valid time range become garbled. On 64-bit systems, > all times before 1970 get turned into timestamps between 2038 and 2106, > which is more convenient but also different from the documented behavior. > > Looking at the Darwin sources [2], it seems that MacOS is inconsistent in > yet another way: all timestamps are wrapped around to a 32-bit unsigned > number when written to the disk, but when read back, all numeric values > lower than 2082844800U are assumed to be invalid, so we cannot represent > the times before 1970 or the times after 2040. > > While all implementations seem to agree on the interpretation of values > between 1970 and 2038, they often differ on the exact range they support > when reading back values outside of the common range: > > MacOS (traditional): 1904-2040 > Apple Documentation: 1904-2040 > MacOS X source comments: 1970-2040 > MacOS X source code: 1970-2038 > 32-bit Linux: 1902-2038 > 64-bit Linux: 1970-2106 > hfsfuse: 1970-2040 > hfsutils (32 bit, old libc) 1902-2038 > hfsutils (32 bit, new libc) 1970-2106 > hfsutils (64 bit) 1904-2040 > hfsplus-utils 1904-2040 > hfsexplorer 1904-2040 > 7-zip 1904-2040 > > Out of the above, the range from 1970 to 2106 seems to be the most useful, > as it allows using HFS and HFS+ beyond year 2038, and this matches the > behavior that most users would see today on Linux, as few people run > 32-bit kernels any more. > > Link: [1] https://developer.apple.com/library/archive/technotes/tn/tn1150.html > Link: [2] https://opensource.apple.com/source/hfs/hfs-407.30.1/core/MacOSStubs.c.auto.html > Link: https://lore.kernel.org/lkml/20180711224625.airwna6gzyatoowe@eaf/ > Cc: Viacheslav Dubeyko <slava@xxxxxxxxxxx> > Suggested-by: "Ernesto A. Fernández" <ernesto.mnd.fernandez@xxxxxxxxx> > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx> > --- > v3: revert back to 1970-2106 time range > fix bugs found in review > merge both patches into one > drop cc:stable tag > v2: treat pre-1970 dates as invalid following MacOS X behavior, > reword and expand changelog text > --- > fs/hfs/hfs_fs.h | 26 ++++++++++++++++++++------ > fs/hfs/inode.c | 4 ++-- > fs/hfsplus/hfsplus_fs.h | 26 +++++++++++++++++++++----- > fs/hfsplus/inode.c | 12 ++++++------ > 4 files changed, 49 insertions(+), 19 deletions(-) > > diff --git a/fs/hfs/hfs_fs.h b/fs/hfs/hfs_fs.h > index 6d0783e2e276..26733051ee50 100644 > --- a/fs/hfs/hfs_fs.h > +++ b/fs/hfs/hfs_fs.h > @@ -242,19 +242,33 @@ extern void hfs_mark_mdb_dirty(struct super_block *sb); > /* > * 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? > +static inline time64_t __hfs_m_to_utime(__be32 mt) > +{ > + time64_t ut = (u32)(be32_to_cpu(mt) - 2082844800U); Ditto. > + > + 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); Ditto. > +} > #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) > > -#define hfs_m_to_utime(time) (struct timespec){ .tv_sec = __hfs_m_to_utime(time) } > -#define hfs_u_to_mtime(time) __hfs_u_to_mtime((time).tv_sec) > -#define hfs_mtime() __hfs_u_to_mtime(get_seconds()) > +#define hfs_m_to_utime(time) (struct timespec64){ .tv_sec = __hfs_m_to_utime(time) } > +#define hfs_u_to_mtime(time) __hfs_u_to_mtime((time).tv_sec) > +#define hfs_mtime() __hfs_u_to_mtime(ktime_get_real_seconds()) > > static inline const char *hfs_mdb_name(struct super_block *sb) > { > diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c > index da243c84e93b..2f224b98ee94 100644 > --- a/fs/hfs/inode.c > +++ b/fs/hfs/inode.c > @@ -351,7 +351,7 @@ static int hfs_read_inode(struct inode *inode, void *data) > inode->i_mode &= ~hsb->s_file_umask; > inode->i_mode |= S_IFREG; > inode->i_ctime = inode->i_atime = inode->i_mtime = > - timespec_to_timespec64(hfs_m_to_utime(rec->file.MdDat)); > + hfs_m_to_utime(rec->file.MdDat); > inode->i_op = &hfs_file_inode_operations; > inode->i_fop = &hfs_file_operations; > inode->i_mapping->a_ops = &hfs_aops; > @@ -362,7 +362,7 @@ static int hfs_read_inode(struct inode *inode, void *data) > HFS_I(inode)->fs_blocks = 0; > inode->i_mode = S_IFDIR | (S_IRWXUGO & ~hsb->s_dir_umask); > inode->i_ctime = inode->i_atime = inode->i_mtime = > - timespec_to_timespec64(hfs_m_to_utime(rec->dir.MdDat)); > + hfs_m_to_utime(rec->dir.MdDat); > inode->i_op = &hfs_dir_inode_operations; > inode->i_fop = &hfs_dir_operations; > break; > diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h > index b8471bf05def..22d0a22c41a3 100644 > --- a/fs/hfsplus/hfsplus_fs.h > +++ b/fs/hfsplus/hfsplus_fs.h > @@ -533,13 +533,29 @@ int hfsplus_submit_bio(struct super_block *sb, sector_t sector, void *buf, > void **data, int op, int op_flags); > int hfsplus_read_wrapper(struct super_block *sb); > > -/* time macros */ > -#define __hfsp_mt2ut(t) (be32_to_cpu(t) - 2082844800U) > -#define __hfsp_ut2mt(t) (cpu_to_be32(t + 2082844800U)) Ditto. > +/* > + * time helpers: convert between 1904-base and 1970-base timestamps > + * > + * 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. > + */ > +static inline time64_t __hfsp_mt2ut(__be32 mt) > +{ > + time64_t ut = (u32)(be32_to_cpu(mt) - 2082844800U); Ditto. > + > + return ut; > +} > + > +static inline __be32 __hfsp_ut2mt(time64_t ut) > +{ > + return cpu_to_be32(lower_32_bits(ut) + 2082844800U); Ditto. > +} > > /* compatibility */ > -#define hfsp_mt2ut(t) (struct timespec){ .tv_sec = __hfsp_mt2ut(t) } > +#define hfsp_mt2ut(t) (struct timespec64){ .tv_sec = __hfsp_mt2ut(t) } > #define hfsp_ut2mt(t) __hfsp_ut2mt((t).tv_sec) > -#define hfsp_now2mt() __hfsp_ut2mt(get_seconds()) > +#define hfsp_now2mt() __hfsp_ut2mt(ktime_get_real_seconds()) > > #endif > diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c > index d131c8ea7eb6..94bd83b36644 100644 > --- a/fs/hfsplus/inode.c > +++ b/fs/hfsplus/inode.c > @@ -504,9 +504,9 @@ int hfsplus_cat_read_inode(struct inode *inode, struct hfs_find_data *fd) > hfsplus_get_perms(inode, &folder->permissions, 1); > set_nlink(inode, 1); > inode->i_size = 2 + be32_to_cpu(folder->valence); > - inode->i_atime = timespec_to_timespec64(hfsp_mt2ut(folder->access_date)); > - inode->i_mtime = timespec_to_timespec64(hfsp_mt2ut(folder->content_mod_date)); > - inode->i_ctime = timespec_to_timespec64(hfsp_mt2ut(folder->attribute_mod_date)); > + inode->i_atime = hfsp_mt2ut(folder->access_date); > + inode->i_mtime = hfsp_mt2ut(folder->content_mod_date); > + inode->i_ctime = hfsp_mt2ut(folder->attribute_mod_date); > HFSPLUS_I(inode)->create_date = folder->create_date; > HFSPLUS_I(inode)->fs_blocks = 0; > if (folder->flags & cpu_to_be16(HFSPLUS_HAS_FOLDER_COUNT)) { > @@ -542,9 +542,9 @@ int hfsplus_cat_read_inode(struct inode *inode, struct hfs_find_data *fd) > init_special_inode(inode, inode->i_mode, > be32_to_cpu(file->permissions.dev)); > } > - inode->i_atime = timespec_to_timespec64(hfsp_mt2ut(file->access_date)); > - inode->i_mtime = timespec_to_timespec64(hfsp_mt2ut(file->content_mod_date)); > - inode->i_ctime = timespec_to_timespec64(hfsp_mt2ut(file->attribute_mod_date)); > + inode->i_atime = hfsp_mt2ut(file->access_date); > + inode->i_mtime = hfsp_mt2ut(file->content_mod_date); > + inode->i_ctime = hfsp_mt2ut(file->attribute_mod_date); > HFSPLUS_I(inode)->create_date = file->create_date; > } else { > pr_err("bad catalog entry used to create inode\n"); > — > 2.20.0 > The patch looks pretty clean and good. Thanks, Viacheslav Dubeyko.
