[PATCH] fat: Allow time_offset to be upto 13 hours

[Jan Kara <jack@suse.cz>]

Currently we limit values of time_offset mount option to be between -12
and 12 hours. However e.g. zone GMT+12 can have a DST correction on top
which makes the total time difference 13 hours. Update the checks in
mount option parsing to allow offset of upto 13 hours.

Reported-by: Volker Kuhlmann <list0570@paradise.net.nz>
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/fat/inode.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 509411dd3698..2041031ab1c8 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -1146,7 +1146,11 @@ static int parse_options(struct super_block *sb, char *options, int is_vfat,
 		case Opt_time_offset:
 			if (match_int(&args[0], &option))
 				return -EINVAL;
-			if (option < -12 * 60 || option > 12 * 60)
+			/*
+			 * Allow for GMT+-12 zones to have DST like
+			 * corrections
+			 */
+			if (option < -13 * 60 || option > 13 * 60)
 				return -EINVAL;
 			opts->tz_set = 1;
 			opts->time_offset = option;
-- 
2.1.4