exfat: introduce mount option 'sys_tz'
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://docs.microsoft.com/en-us/windows/win32/fileio/exfat-specification#74102-offsetvalid-field
Signed-off-by: Chung-Chiang Cheng <cccheng@synology.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
diff --git a/misc.c b/misc.c
index 47c3682..c03a586 100644
--- a/misc.c
+++ b/misc.c
@@ -84,6 +84,13 @@
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). */
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 19, 0)
void exfat_get_entry_time(struct exfat_sb_info *sbi, struct timespec64 *ts,
@@ -111,8 +118,7 @@
/* 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. */