From 9b002894b4c252169abc26720452bf3746114b20 Mon Sep 17 00:00:00 2001 From: Chung-Chiang Cheng Date: Wed, 6 Apr 2022 17:55:52 +0800 Subject: [PATCH] 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 Acked-by: Sungjong Seo Signed-off-by: Namjae Jeon --- 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 c6800b8..82e5074 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 d5bd8e6..9380e01 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 8ca21e7..3e0f67b 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 -- 2.7.4