[PATCHv2] devpts: fix to set default values of mount options

[Wei Yongjun <yjwei@cn.fujitsu.com>]

If devpts is mounted with no option specified, the default
values of mount options will no be set. This happend in my
Fedora11Beta box.

  $ mkdir /dev/pts2

  $ mount -t devpts devpts /dev/pts2
  $ cat /proc/mounts
  devpts /dev/pts2 devpts rw,relatime,mode=000,ptmxmode=000 0 0

  # umount /dev/pts2
  $ mount -t devpts -o gid=0 devpts /dev/pts2
  $ cat /proc/mounts
  devpts /dev/pts2 devpts rw,relatime,gid=0,mode=600,ptmxmode=000 0 0

This patch fixed this problem.

Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
---
 fs/devpts/inode.c |   12 +++++++-----
 1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 21165cf..13392b5 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -105,6 +105,9 @@ static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts)
 	if (op == PARSE_MOUNT)
 		opts->newinstance = 0;
 
+	if (!data)
+		return 0;
+
 	while ((p = strsep(&data, ",")) != NULL) {
 		substring_t args[MAX_OPT_ARGS];
 		int token;
@@ -356,11 +359,10 @@ static int devpts_get_sb(struct file_system_type *fs_type,
 	struct super_block *s;
 
 	memset(&opts, 0, sizeof(opts));
-	if (data) {
-		error = parse_mount_options(data, PARSE_MOUNT, &opts);
-		if (error)
-			return error;
-	}
+
+	error = parse_mount_options(data, PARSE_MOUNT, &opts);
+	if (error)
+		return error;
 
 	if (opts.newinstance)
 		s = sget(fs_type, NULL, set_anon_super, NULL);
-- 
1.5.3.8