text: #ifndef _SYSV_FS_SB
  #define _SYSV_FS_SB
  
  /*
   * SystemV/V7/Coherent super-block data in memory
   * The SystemV/V7/Coherent superblock contains dynamic data (it gets modified
   * while the system is running). This is in contrast to the Minix and Berkeley
   * filesystems (where the superblock is never modified). This affects the
   * sync() operation: we must keep the superblock in a disk buffer and use this
   * one as our "working copy".
   */
  
  struct sysv_sb_info {
  	int	       s_type;		/* file system type: FSTYPE_{XENIX|SYSV|COH} */
  	char	       s_bytesex;	/* bytesex (le/be/pdp) */
  	char	       s_truncate;	/* if 1: names > SYSV_NAMELEN chars are truncated */
  					/* if 0: they are disallowed (ENAMETOOLONG) */
  	nlink_t        s_link_max;	/* max number of hard links to a file */
  	unsigned int   s_inodes_per_block;	/* number of inodes per block */
  	unsigned int   s_inodes_per_block_1;	/* inodes_per_block - 1 */
  	unsigned int   s_inodes_per_block_bits;	/* log2(inodes_per_block) */
  	unsigned int   s_ind_per_block;		/* number of indirections per block */
  	unsigned int   s_ind_per_block_bits;	/* log2(ind_per_block) */
  	unsigned int   s_ind_per_block_2;	/* ind_per_block ^ 2 */
  	unsigned int   s_toobig_block;		/* 10 + ipb + ipb^2 + ipb^3 */
  	unsigned int   s_block_base;	/* physical block number of block 0 */
  	unsigned short s_fic_size;	/* free inode cache size, NICINOD */
  	unsigned short s_flc_size;	/* free block list chunk size, NICFREE */
  	/* The superblock is kept in one or two disk buffers: */
  	struct buffer_head *s_bh1;
  	struct buffer_head *s_bh2;
  	/* These are pointers into the disk buffer, to compensate for
  	   different superblock layout. */
  	char *         s_sbd1;		/* entire superblock data, for part 1 */
  	char *         s_sbd2;		/* entire superblock data, for part 2 */
  	u16            *s_sb_fic_count;	/* pointer to s_sbd->s_ninode */
          u16            *s_sb_fic_inodes; /* pointer to s_sbd->s_inode */
  	u16            *s_sb_total_free_inodes; /* pointer to s_sbd->s_tinode */
  	u16            *s_bcache_count;	/* pointer to s_sbd->s_nfree */
  	u32	       *s_bcache;	/* pointer to s_sbd->s_free */
  	u32            *s_free_blocks;	/* pointer to s_sbd->s_tfree */
  	u32            *s_sb_time;	/* pointer to s_sbd->s_time */
  	u32            *s_sb_state;	/* pointer to s_sbd->s_state, only FSTYPE_SYSV */
  	/* We keep those superblock entities that don't change here;
  	   this saves us an indirection and perhaps a conversion. */
  	u32            s_firstinodezone; /* index of first inode zone */
  	u32            s_firstdatazone;	/* same as s_sbd->s_isize */
  	u32            s_ninodes;	/* total number of inodes */
  	u32            s_ndatazones;	/* total number of data zones */
  	u32            s_nzones;	/* same as s_sbd->s_fsize */
  	u16	       s_namelen;       /* max length of dir entry */
  };
  /* The field s_toobig_block is currently unused. */
  
  /* sv_ == u.sysv_sb.s_ */
  #define sv_type					u.sysv_sb.s_type
  #define sv_bytesex				u.sysv_sb.s_bytesex
  #define sv_truncate				u.sysv_sb.s_truncate
  #define sv_link_max				u.sysv_sb.s_link_max
  #define sv_inodes_per_block			u.sysv_sb.s_inodes_per_block
  #define sv_inodes_per_block_1			u.sysv_sb.s_inodes_per_block_1
  #define sv_inodes_per_block_bits		u.sysv_sb.s_inodes_per_block_bits
  #define sv_ind_per_block			u.sysv_sb.s_ind_per_block
  #define sv_ind_per_block_bits			u.sysv_sb.s_ind_per_block_bits
  #define sv_ind_per_block_2			u.sysv_sb.s_ind_per_block_2
  #define sv_toobig_block				u.sysv_sb.s_toobig_block
  #define sv_block_base				u.sysv_sb.s_block_base
  #define sv_fic_size				u.sysv_sb.s_fic_size
  #define sv_flc_size				u.sysv_sb.s_flc_size
  #define sv_bh1					u.sysv_sb.s_bh1
  #define sv_bh2					u.sysv_sb.s_bh2
  #define sv_sbd1					u.sysv_sb.s_sbd1
  #define sv_sbd2					u.sysv_sb.s_sbd2
  #define sv_sb_fic_count				u.sysv_sb.s_sb_fic_count
  #define sv_sb_fic_inodes			u.sysv_sb.s_sb_fic_inodes
  #define sv_sb_total_free_inodes			u.sysv_sb.s_sb_total_free_inodes
  #define sv_bcache_count				u.sysv_sb.s_bcache_count
  #define sv_bcache				u.sysv_sb.s_bcache
  #define sv_free_blocks				u.sysv_sb.s_free_blocks
  #define sv_sb_time				u.sysv_sb.s_sb_time
  #define sv_sb_state				u.sysv_sb.s_sb_state
  #define sv_firstinodezone			u.sysv_sb.s_firstinodezone
  #define sv_firstdatazone			u.sysv_sb.s_firstdatazone
  #define sv_ninodes				u.sysv_sb.s_ninodes
  #define sv_ndatazones				u.sysv_sb.s_ndatazones
  #define sv_nzones				u.sysv_sb.s_nzones
  #define sv_namelen                              u.sysv_sb.s_namelen
  
  #endif
  