nilfs2: clarify byte offset in super block format

This inserts comments indicating hexadecimal offset in declaration of
nilfs_super_block structure so that people can know offset of its
fields without counting from the head.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

include/linux/nilfs2_fs.h

@@ -160,7 +160,7 @@ struct nilfs_super_root {
  * struct nilfs_super_block - structure of super block on disk
  */
 struct nilfs_super_block {
-	__le32	s_rev_level;		/* Revision level */
+/*00*/	__le32	s_rev_level;		/* Revision level */
 	__le16	s_minor_rev_level;	/* minor revision level */
 	__le16	s_magic;		/* Magic signature */
 
@@ -169,47 +169,47 @@ struct nilfs_super_block {
 					   is excluded. */
 	__le16  s_flags;		/* flags */
 	__le32  s_crc_seed;		/* Seed value of CRC calculation */
-	__le32	s_sum;			/* Check sum of super block */
+/*10*/	__le32	s_sum;			/* Check sum of super block */
 
 	__le32	s_log_block_size;	/* Block size represented as follows
 					   blocksize =
 					       1 << (s_log_block_size + 10) */
 	__le64  s_nsegments;		/* Number of segments in filesystem */
-	__le64  s_dev_size;		/* block device size in bytes */
+/*20*/	__le64  s_dev_size;		/* block device size in bytes */
 	__le64	s_first_data_block;	/* 1st seg disk block number */
-	__le32  s_blocks_per_segment;   /* number of blocks per full segment */
+/*30*/	__le32  s_blocks_per_segment;   /* number of blocks per full segment */
 	__le32	s_r_segments_percentage; /* Reserved segments percentage */
 
 	__le64  s_last_cno;		/* Last checkpoint number */
-	__le64  s_last_pseg;		/* disk block addr pseg written last */
+/*40*/	__le64  s_last_pseg;		/* disk block addr pseg written last */
 	__le64  s_last_seq;             /* seq. number of seg written last */
-	__le64	s_free_blocks_count;	/* Free blocks count */
+/*50*/	__le64	s_free_blocks_count;	/* Free blocks count */
 
 	__le64	s_ctime;		/* Creation time (execution time of
 					   newfs) */
-	__le64	s_mtime;		/* Mount time */
+/*60*/	__le64	s_mtime;		/* Mount time */
 	__le64	s_wtime;		/* Write time */
-	__le16	s_mnt_count;		/* Mount count */
+/*70*/	__le16	s_mnt_count;		/* Mount count */
 	__le16	s_max_mnt_count;	/* Maximal mount count */
 	__le16	s_state;		/* File system state */
 	__le16	s_errors;		/* Behaviour when detecting errors */
 	__le64	s_lastcheck;		/* time of last check */
 
-	__le32	s_checkinterval;	/* max. time between checks */
+/*80*/	__le32	s_checkinterval;	/* max. time between checks */
 	__le32	s_creator_os;		/* OS */
 	__le16	s_def_resuid;		/* Default uid for reserved blocks */
 	__le16	s_def_resgid;		/* Default gid for reserved blocks */
 	__le32	s_first_ino;		/* First non-reserved inode */
 
-	__le16  s_inode_size;		/* Size of an inode */
+/*90*/	__le16  s_inode_size;		/* Size of an inode */
 	__le16  s_dat_entry_size;       /* Size of a dat entry */
 	__le16  s_checkpoint_size;      /* Size of a checkpoint */
 	__le16	s_segment_usage_size;	/* Size of a segment usage */
 
-	__u8	s_uuid[16];		/* 128-bit uuid for volume */
-	char	s_volume_name[80];	/* volume name */
+/*98*/	__u8	s_uuid[16];		/* 128-bit uuid for volume */
+/*A8*/	char	s_volume_name[80];	/* volume name */
 
-	__le32  s_c_interval;           /* Commit interval of segment */
+/*F8*/	__le32  s_c_interval;           /* Commit interval of segment */
 	__le32  s_c_block_max;          /* Threshold of data amount for
 					   the segment construction */
 	__u32	s_reserved[192];	/* padding to the end of the block */