3 files changed, 28 insertions, 9 deletions

diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index 623f36f0423..12701a56775 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -29,6 +29,7 @@ struct fat_mount_options {
         unsigned short fs_fmask;
         unsigned short fs_dmask;
         unsigned short codepage;   /* Codepage for shortname conversions */
+        int time_offset;           /* Offset of timestamps from UTC (in minutes) */
         char *iocharset;           /* Charset used for filename input/display */
         unsigned short shortname;  /* flags for shortname display/create rule */
         unsigned char name_check;  /* r = relaxed, n = normal, s = strict */
@@ -45,7 +46,7 @@ struct fat_mount_options {
                  flush:1,          /* write things quickly */
                  nocase:1,         /* Does this need case conversion? 0=need case conversion*/
                  usefree:1,        /* Use free_clusters for FAT32 */
-                 tz_utc:1,         /* Filesystem timestamps are in UTC */
+                 tz_set:1,         /* Filesystem timestamps' offset set */
                  rodir:1,          /* allow ATTR_RO for directory */
                  discard:1,        /* Issue discard requests on deletions */
                  nfs:1;            /* Do extra work needed for NFS export */
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 7b186a5d51b..59ac83be2d5 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -778,8 +778,12 @@ static int fat_show_options(struct seq_file *m, struct dentry *root)
         }
         if (opts->flush)
                 seq_puts(m, ",flush");
-        if (opts->tz_utc)
-                seq_puts(m, ",tz=UTC");
+        if (opts->tz_set) {
+                if (opts->time_offset)
+                        seq_printf(m, ",time_offset=%d", opts->time_offset);
+                else
+                        seq_puts(m, ",tz=UTC");
+        }
         if (opts->errors == FAT_ERRORS_CONT)
                 seq_puts(m, ",errors=continue");
         else if (opts->errors == FAT_ERRORS_PANIC)
@@ -801,7 +805,8 @@ enum {
         Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
         Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
         Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
-        Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_err,
+        Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
+        Opt_err,
 };
 
 static const match_table_t fat_tokens = {
@@ -826,6 +831,7 @@ static const match_table_t fat_tokens = {
         {Opt_immutable, "sys_immutable"},
         {Opt_flush, "flush"},
         {Opt_tz_utc, "tz=UTC"},
+        {Opt_time_offset, "time_offset=%d"},
         {Opt_err_cont, "errors=continue"},
         {Opt_err_panic, "errors=panic"},
         {Opt_err_ro, "errors=remount-ro"},
@@ -910,7 +916,7 @@ static int parse_options(struct super_block *sb, char *options, int is_vfat,
         opts->utf8 = opts->unicode_xlate = 0;
         opts->numtail = 1;
         opts->usefree = opts->nocase = 0;
-        opts->tz_utc = 0;
+        opts->tz_set = 0;
         opts->nfs = 0;
         opts->errors = FAT_ERRORS_RO;
         *debug = 0;
@@ -1006,8 +1012,17 @@ static int parse_options(struct super_block *sb, char *options, int is_vfat,
                 case Opt_flush:
                         opts->flush = 1;
                         break;
+                case Opt_time_offset:
+                        if (match_int(&args[0], &option))
+                                return 0;
+                        if (option < -12 * 60 || option > 12 * 60)
+                                return 0;
+                        opts->tz_set = 1;
+                        opts->time_offset = option;
+                        break;
                 case Opt_tz_utc:
-                        opts->tz_utc = 1;
+                        opts->tz_set = 1;
+                        opts->time_offset = 0;
                         break;
                 case Opt_err_cont:
                         opts->errors = FAT_ERRORS_CONT;
diff --git a/fs/fat/misc.c b/fs/fat/misc.c
index 6d93360ca0c..5eb600dc43a 100644
--- a/fs/fat/misc.c
+++ b/fs/fat/misc.c
@@ -212,8 +212,10 @@ void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
                    + days_in_year[month] + day
                    + DAYS_DELTA) * SECS_PER_DAY;
 
-        if (!sbi->options.tz_utc)
+        if (!sbi->options.tz_set)
                 second += sys_tz.tz_minuteswest * SECS_PER_MIN;
+        else
+                second -= sbi->options.time_offset * SECS_PER_MIN;
 
         if (time_cs) {
                 ts->tv_sec = second + (time_cs / 100);
@@ -229,8 +231,9 @@ void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
                        __le16 *time, __le16 *date, u8 *time_cs)
 {
         struct tm tm;
-        time_to_tm(ts->tv_sec, sbi->options.tz_utc ? 0 :
-                   -sys_tz.tz_minuteswest * 60, &tm);
+        time_to_tm(ts->tv_sec,
+                   (sbi->options.tz_set ? sbi->options.time_offset :
+                   -sys_tz.tz_minuteswest) * SECS_PER_MIN, &tm);
 
         /*  FAT can only support year between 1980 to 2107 */
         if (tm.tm_year < 1980 - 1900) {