--- 1a34c1c84604528cc8ba49e3e8dcbca65a356cc9
+++ 73490d9ecc3716f55f1518c57b9ff40a4188e7ef
@@ -1931,6 +1931,11 @@ extern __le16 ext4_group_desc_csum(struc
 				   struct ext4_group_desc *gdp);
 extern int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 group,
 				       struct ext4_group_desc *gdp);
+/* for debugging, sangwoo2.lee */
+extern void print_bh(struct super_block *sb, struct buffer_head *bh, int start, int len);
+extern void print_block_data(struct super_block *sb, sector_t blocknr, unsigned char *data_to_dump, int start, int len);
+/* for debugging */
+
 
 static inline ext4_fsblk_t ext4_blocks_count(struct ext4_super_block *es)
 {