1 files changed, 14 insertions, 9 deletions

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 63a4a59e4148..c68edb969441 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -90,6 +90,15 @@ static inline struct super_block *pts_sb_from_inode(struct inode *inode)
 #define PARSE_MOUNT     0
 #define PARSE_REMOUNT   1
 
+/*
+ * parse_mount_options():
+ *      Set @opts to mount options specified in @data. If an option is not
+ *      specified in @data, set it to its default value. The exception is
+ *      'newinstance' option which can only be set/cleared on a mount (i.e.
+ *      cannot be changed during remount).
+ *
+ * Note: @data may be NULL (in which case all options are set to default).
+ */
 static int parse_mount_options(char *data, int op, struct pts_mount_opts *opts)
 {
         char *p;
@@ -355,12 +364,9 @@ static int devpts_get_sb(struct file_system_type *fs_type,
         struct pts_mount_opts opts;
         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);
@@ -389,11 +395,10 @@ static int devpts_get_sb(struct file_system_type *fs_type,
         return 0;
 
 out_dput:
-        dput(s->s_root);
+        dput(s->s_root); /* undo dget() in simple_set_mnt() */
 
 out_undo_sget:
-        up_write(&s->s_umount);
-        deactivate_super(s);
+        deactivate_locked_super(s);
         return error;
 }