> EXFAT_TZ_VALID bit in {create,modify,access}_tz is corresponding to
> OffsetValid field in exfat specification [1]. When this bit isn't set,
> timestamps should be treated as having the same UTC offset as the current
> local time.
>
> Currently, there is an option 'time_offset' for users to specify the UTC
> offset for this issue. This patch introduces a new mount option 'sys_tz'
> to use system timezone as time offset.
>
> Link: [1] https://protect2.fireeye.com/v1/url?k=6c606ee0-0d1d8463-
> 6c61e5af-74fe48600158-7870d6304b957d98&q=1&e=3704e121-39fa-4c75-a3c8-
> a4e968c00dbf&u=https%3A%2F%2Fdocs.microsoft.com%2Fen-
> us%2Fwindows%2Fwin32%2Ffileio%2Fexfat-specification%2374102-offsetvalid-
> field
>
> Signed-off-by: Chung-Chiang Cheng <cccheng@xxxxxxxxxxxx>
Looks good!
Acked-by: Sungjong Seo <sj1557.seo@xxxxxxxxxxx>
> ---
> fs/exfat/exfat_fs.h | 1 +
> fs/exfat/misc.c | 10 ++++++++--
> fs/exfat/super.c | 9 ++++++++-
> 3 files changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h index
> c6800b880920..82e507413291 100644
> --- a/fs/exfat/exfat_fs.h
> +++ b/fs/exfat/exfat_fs.h
> @@ -203,6 +203,7 @@ struct exfat_mount_options {
> /* on error: continue, panic, remount-ro */
> enum exfat_error_mode errors;
> unsigned utf8:1, /* Use of UTF-8 character set */
> + sys_tz:1, /* Use local timezone */
> discard:1, /* Issue discard requests on deletions */
> keep_last_dots:1; /* Keep trailing periods in paths */
> int time_offset; /* Offset of timestamps from UTC (in minutes) */
> diff --git a/fs/exfat/misc.c b/fs/exfat/misc.c index
> d5bd8e6d9741..9380e0188b55 100644
> --- a/fs/exfat/misc.c
> +++ b/fs/exfat/misc.c
> @@ -74,6 +74,13 @@ static void exfat_adjust_tz(struct timespec64 *ts, u8
> tz_off)
> ts->tv_sec += TIMEZONE_SEC(0x80 - tz_off); }
>
> +static inline int exfat_tz_offset(struct exfat_sb_info *sbi) {
> + if (sbi->options.sys_tz)
> + return -sys_tz.tz_minuteswest;
> + return sbi->options.time_offset;
> +}
> +
> /* Convert a EXFAT time/date pair to a UNIX date (seconds since 1 1 70).
> */ void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64
> *ts,
> u8 tz, __le16 time, __le16 date, u8 time_cs) @@ -96,8 +103,7
> @@ void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64
> *ts,
> /* Adjust timezone to UTC0. */
> exfat_adjust_tz(ts, tz & ~EXFAT_TZ_VALID);
> else
> - /* Convert from local time to UTC using time_offset. */
> - ts->tv_sec -= sbi->options.time_offset * SECS_PER_MIN;
> + ts->tv_sec -= exfat_tz_offset(sbi) * SECS_PER_MIN;
> }
>
> /* Convert linear UNIX date to a EXFAT time/date pair. */ diff --git
> a/fs/exfat/super.c b/fs/exfat/super.c index 8ca21e7917d1..3e0f67b2103e
> 100644
> --- a/fs/exfat/super.c
> +++ b/fs/exfat/super.c
> @@ -170,7 +170,9 @@ static int exfat_show_options(struct seq_file *m,
> struct dentry *root)
> seq_puts(m, ",discard");
> if (opts->keep_last_dots)
> seq_puts(m, ",keep_last_dots");
> - if (opts->time_offset)
> + if (opts->sys_tz)
> + seq_puts(m, ",sys_tz");
> + else if (opts->time_offset)
> seq_printf(m, ",time_offset=%d", opts->time_offset);
> return 0;
> }
> @@ -214,6 +216,7 @@ enum {
> Opt_errors,
> Opt_discard,
> Opt_keep_last_dots,
> + Opt_sys_tz,
> Opt_time_offset,
>
> /* Deprecated options */
> @@ -241,6 +244,7 @@ static const struct fs_parameter_spec
> exfat_parameters[] = {
> fsparam_enum("errors", Opt_errors,
> exfat_param_enums),
> fsparam_flag("discard", Opt_discard),
> fsparam_flag("keep_last_dots", Opt_keep_last_dots),
> + fsparam_flag("sys_tz", Opt_sys_tz),
> fsparam_s32("time_offset", Opt_time_offset),
> __fsparam(NULL, "utf8", Opt_utf8,
> fs_param_deprecated,
> NULL),
> @@ -298,6 +302,9 @@ static int exfat_parse_param(struct fs_context *fc,
> struct fs_parameter *param)
> case Opt_keep_last_dots:
> opts->keep_last_dots = 1;
> break;
> + case Opt_sys_tz:
> + opts->sys_tz = 1;
> + break;
> case Opt_time_offset:
> /*
> * Make the limit 24 just in case someone invents something
> --
> 2.34.1
