exofs_mount(): fix leaks on failure exits

... and don't abuse mount_nodev(), while we are at it.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Reviewed-by: David Howells <dhowells@redhat.com>

fs/exofs/super.c

@@ -705,21 +705,18 @@ static int exofs_read_lookup_dev_table(struct exofs_sb_info *sbi,
 /*
  * Read the superblock from the OSD and fill in the fields
  */
-static int exofs_fill_super(struct super_block *sb, void *data, int silent)
+static int exofs_fill_super(struct super_block *sb,
+				struct exofs_mountopt *opts,
+				struct exofs_sb_info *sbi,
+				int silent)
 {
 	struct inode *root;
-	struct exofs_mountopt *opts = data;
-	struct exofs_sb_info *sbi;	/*extended info                  */
 	struct osd_dev *od;		/* Master device                 */
 	struct exofs_fscb fscb;		/*on-disk superblock info        */
 	struct ore_comp comp;
 	unsigned table_count;
 	int ret;
 
-	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
-	if (!sbi)
-		return -ENOMEM;
-
 	/* use mount options to fill superblock */
 	if (opts->is_osdname) {
 		struct osd_dev_info odi = {.systemid_len = 0};
@@ -863,7 +860,9 @@ static struct dentry *exofs_mount(struct file_system_type *type,
 			  int flags, const char *dev_name,
 			  void *data)
 {
+	struct super_block *s;
 	struct exofs_mountopt opts;
+	struct exofs_sb_info *sbi;
 	int ret;
 
 	ret = parse_options(data, &opts);
@@ -872,9 +871,31 @@ static struct dentry *exofs_mount(struct file_system_type *type,
 		return ERR_PTR(ret);
 	}
 
+	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+	if (!sbi) {
+		kfree(opts.dev_name);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	s = sget(type, NULL, set_anon_super, flags, NULL);
+
+	if (IS_ERR(s)) {
+		kfree(opts.dev_name);
+		kfree(sbi);
+		return ERR_CAST(s);
+	}
+
 	if (!opts.dev_name)
 		opts.dev_name = dev_name;
-	return mount_nodev(type, flags, &opts, exofs_fill_super);
+
+
+	ret = exofs_fill_super(s, &opts, sbi, flags & SB_SILENT ? 1 : 0);
+	if (ret) {
+		deactivate_locked_super(s);
+		return ERR_PTR(ret);
+	}
+	s->s_flags |= SB_ACTIVE;
+	return dget(s->s_root);
 }
 
 /*