f2fs: remove debufs dir if debugfs_create_file() failed

When debugfs_create_file() failed in f2fs_create_root_stats(),
debugfs_root should be remove.
Signed-off-by: Younger Liu <liuyiyang@hisense.com>
Cc: Younger Liu <younger.liucn@gmail.com>
Cc: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

fs/f2fs/debug.c

@@ -340,14 +340,32 @@ void f2fs_destroy_stats(struct f2fs_sb_info *sbi)
 
 void __init f2fs_create_root_stats(void)
 {
+	struct dentry *file;
+
 	debugfs_root = debugfs_create_dir("f2fs", NULL);
-	if (debugfs_root)
-		debugfs_create_file("status", S_IRUGO, debugfs_root,
-					 NULL, &stat_fops);
+	if (!debugfs_root)
+		goto bail;
+
+	file = debugfs_create_file("status", S_IRUGO, debugfs_root,
+			NULL, &stat_fops);
+	if (!file)
+		goto free_debugfs_dir;
+
+	return;
+
+free_debugfs_dir:
+	debugfs_remove(debugfs_root);
+
+bail:
+	debugfs_root = NULL;
+	return;
 }
 
 void f2fs_destroy_root_stats(void)
 {
+	if (!debugfs_root)
+		return;
+
 	debugfs_remove_recursive(debugfs_root);
 	debugfs_root = NULL;
 }