f2fs: add quota_ino feature infra

This patch adds quota_ino feature infra to be used for quota files.

Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index 50a8ee5..ce34007 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -36,6 +36,9 @@
 #define F2FS_NODE_INO(sbi)	((sbi)->node_ino_num)
 #define F2FS_META_INO(sbi)	((sbi)->meta_ino_num)
 
+#define F2FS_QUOTA_INO		3
+#define F2FS_MAX_QUOTAS		3
+
 #define F2FS_IO_SIZE(sbi)	(1 << (sbi)->write_io_size_bits) /* Blocks */
 #define F2FS_IO_SIZE_KB(sbi)	(1 << ((sbi)->write_io_size_bits + 2)) /* KB */
 #define F2FS_IO_SIZE_BYTES(sbi)	(1 << ((sbi)->write_io_size_bits + 12)) /* B */
@@ -108,7 +111,8 @@ struct f2fs_super_block {
 	__u8 encryption_level;		/* versioning level for encryption */
 	__u8 encrypt_pw_salt[16];	/* Salt used for string2key algorithm */
 	struct f2fs_device devs[MAX_DEVICES];	/* device list */
-	__u8 reserved[327];		/* valid reserved region */
+	__le32 qf_ino[F2FS_MAX_QUOTAS];	/* quota inode numbers */
+	__u8 reserved[315];		/* valid reserved region */
 } __packed;
 
 /*