#ifndef _LINUX_SYSV_FS_H
  #define _LINUX_SYSV_FS_H
  
  #define __packed2__	__attribute__((packed, aligned(2)))
  
  
  #ifndef __KERNEL__
  typedef u16 __fs16;
  typedef u32 __fs16;
  #endif
  
  /* inode numbers are 16 bit */
  typedef __fs16 sysv_ino_t;
  
  /* Block numbers are 24 bit, sometimes stored in 32 bit.
     On Coherent FS, they are always stored in PDP-11 manner: the least
     significant 16 bits come last. */
  typedef __fs32 sysv_zone_t;
  
  /* 0 is non-existent */
  #define SYSV_BADBL_INO	1	/* inode of bad blocks file */
  #define SYSV_ROOT_INO	2	/* inode of root directory */
  
  
  /* Xenix super-block data on disk */
  #define XENIX_NICINOD	100	/* number of inode cache entries */
  #define XENIX_NICFREE	100	/* number of free block list chunk entries */
  struct xenix_super_block {
  	__fs16		s_isize; /* index of first data zone */
  	__fs32		s_fsize __packed2__; /* total number of zones of this fs */
  	/* the start of the free block list: */
  	__fs16		s_nfree;	/* number of free blocks in s_free, <= XENIX_NICFREE */
  	sysv_zone_t	s_free[XENIX_NICFREE]; /* first free block list chunk */
  	/* the cache of free inodes: */
  	__fs16		s_ninode; /* number of free inodes in s_inode, <= XENIX_NICINOD */
  	sysv_ino_t	s_inode[XENIX_NICINOD]; /* some free inodes */
  	/* locks, not used by Linux: */
  	char		s_flock;	/* lock during free block list manipulation */
  	char		s_ilock;	/* lock during inode cache manipulation */
  	char		s_fmod;		/* super-block modified flag */
  	char		s_ronly;	/* flag whether fs is mounted read-only */
  	__fs32		s_time __packed2__; /* time of last super block update */
  	__fs32		s_tfree __packed2__; /* total number of free zones */
  	__fs16		s_tinode;	/* total number of free inodes */
  	__fs16		s_dinfo[4];	/* device information ?? */
  	char		s_fname[6];	/* file system volume name */
  	char		s_fpack[6];	/* file system pack name */
  	char		s_clean;	/* set to 0x46 when filesystem is properly unmounted */
  	char		s_fill[371];
  	s32		s_magic;	/* version of file system */
  	__fs32		s_type;		/* type of file system: 1 for 512 byte blocks
  								2 for 1024 byte blocks
  								3 for 2048 byte blocks */
  								
  };
  
  /*
   * SystemV FS comes in two variants:
   * sysv2: System V Release 2 (e.g. Microport), structure elements aligned(2).
   * sysv4: System V Release 4 (e.g. Consensys), structure elements aligned(4).
   */
  #define SYSV_NICINOD	100	/* number of inode cache entries */
  #define SYSV_NICFREE	50	/* number of free block list chunk entries */
  
  /* SystemV4 super-block data on disk */
  struct sysv4_super_block {
  	__fs16	s_isize;	/* index of first data zone */
  	u16	s_pad0;
  	__fs32	s_fsize;	/* total number of zones of this fs */
  	/* the start of the free block list: */
  	__fs16	s_nfree;	/* number of free blocks in s_free, <= SYSV_NICFREE */
  	u16	s_pad1;
  	sysv_zone_t	s_free[SYSV_NICFREE]; /* first free block list chunk */
  	/* the cache of free inodes: */
  	__fs16	s_ninode;	/* number of free inodes in s_inode, <= SYSV_NICINOD */
  	u16	s_pad2;
  	sysv_ino_t     s_inode[SYSV_NICINOD]; /* some free inodes */
  	/* locks, not used by Linux: */
  	char	s_flock;	/* lock during free block list manipulation */
  	char	s_ilock;	/* lock during inode cache manipulation */
  	char	s_fmod;		/* super-block modified flag */
  	char	s_ronly;	/* flag whether fs is mounted read-only */
  	__fs32	s_time;		/* time of last super block update */
  	__fs16	s_dinfo[4];	/* device information ?? */
  	__fs32	s_tfree;	/* total number of free zones */
  	__fs16	s_tinode;	/* total number of free inodes */
  	u16	s_pad3;
  	char	s_fname[6];	/* file system volume name */
  	char	s_fpack[6];	/* file system pack name */
  	s32	s_fill[12];
  	__fs32	s_state;	/* file system state: 0x7c269d38-s_time means clean */
  	s32	s_magic;	/* version of file system */
  	__fs32	s_type;		/* type of file system: 1 for 512 byte blocks
  								2 for 1024 byte blocks */
  };
  
  /* SystemV2 super-block data on disk */
  struct sysv2_super_block {
  	__fs16	s_isize; 		/* index of first data zone */
  	__fs32	s_fsize __packed2__;	/* total number of zones of this fs */
  	/* the start of the free block list: */
  	__fs16	s_nfree;		/* number of free blocks in s_free, <= SYSV_NICFREE */
  	sysv_zone_t s_free[SYSV_NICFREE];	/* first free block list chunk */
  	/* the cache of free inodes: */
  	__fs16	s_ninode;		/* number of free inodes in s_inode, <= SYSV_NICINOD */
  	sysv_ino_t     s_inode[SYSV_NICINOD]; /* some free inodes */
  	/* locks, not used by Linux: */
  	char	s_flock;		/* lock during free block list manipulation */
  	char	s_ilock;		/* lock during inode cache manipulation */
  	char	s_fmod;			/* super-block modified flag */
  	char	s_ronly;		/* flag whether fs is mounted read-only */
  	__fs32	s_time __packed2__;	/* time of last super block update */
  	__fs16	s_dinfo[4];		/* device information ?? */
  	__fs32	s_tfree __packed2__;	/* total number of free zones */
  	__fs16	s_tinode;		/* total number of free inodes */
  	char	s_fname[6];		/* file system volume name */
  	char	s_fpack[6];		/* file system pack name */
  	s32	s_fill[14];
  	__fs32	s_state;		/* file system state: 0xcb096f43 means clean */
  	s32	s_magic;		/* version of file system */
  	__fs32	s_type;			/* type of file system: 1 for 512 byte blocks
  								2 for 1024 byte blocks */
  };
  
  /* V7 super-block data on disk */
  #define V7_NICINOD     100     /* number of inode cache entries */
  #define V7_NICFREE     50      /* number of free block list chunk entries */
  struct v7_super_block {
  	__fs16 s_isize;        /* index of first data zone */
  	__fs32 s_fsize __packed2__; /* total number of zones of this fs */
  	/* the start of the free block list: */
  	__fs16 s_nfree;        /* number of free blocks in s_free, <= V7_NICFREE */
  	sysv_zone_t s_free[V7_NICFREE]; /* first free block list chunk */
  	/* the cache of free inodes: */
  	__fs16 s_ninode;       /* number of free inodes in s_inode, <= V7_NICINOD */
  	sysv_ino_t      s_inode[V7_NICINOD]; /* some free inodes */
  	/* locks, not used by Linux or V7: */
  	char    s_flock;        /* lock during free block list manipulation */
  	char    s_ilock;        /* lock during inode cache manipulation */
  	char    s_fmod;         /* super-block modified flag */
  	char    s_ronly;        /* flag whether fs is mounted read-only */
  	__fs32  s_time __packed2__; /* time of last super block update */
  	/* the following fields are not maintained by V7: */
  	__fs32  s_tfree __packed2__; /* total number of free zones */
  	__fs16  s_tinode;       /* total number of free inodes */
  	__fs16  s_m;            /* interleave factor */
  	__fs16  s_n;            /* interleave factor */
  	char    s_fname[6];     /* file system name */
  	char    s_fpack[6];     /* file system pack name */
  };
  /* Constants to aid sanity checking */
  /* This is not a hard limit, nor enforced by v7 kernel. It's actually just
   * the limit used by Seventh Edition's ls, though is high enough to assume
   * that no reasonable file system would have that much entries in root
   * directory. Thus, if we see anything higher, we just probably got the
   * endiannes wrong. */
  #define V7_NFILES	1024
  /* The disk addresses are three-byte (despite direct block addresses being
   * aligned word-wise in inode). If the most significant byte is non-zero,
   * something is most likely wrong (not a filesystem, bad bytesex). */
  #define V7_MAXSIZE	0x00ffffff
  
  /* Coherent super-block data on disk */
  #define COH_NICINOD	100	/* number of inode cache entries */
  #define COH_NICFREE	64	/* number of free block list chunk entries */
  struct coh_super_block {
  	__fs16		s_isize;	/* index of first data zone */
  	__fs32		s_fsize __packed2__; /* total number of zones of this fs */
  	/* the start of the free block list: */
  	__fs16 s_nfree;	/* number of free blocks in s_free, <= COH_NICFREE */
  	sysv_zone_t	s_free[COH_NICFREE] __packed2__; /* first free block list chunk */
  	/* the cache of free inodes: */
  	__fs16		s_ninode;	/* number of free inodes in s_inode, <= COH_NICINOD */
  	sysv_ino_t	s_inode[COH_NICINOD]; /* some free inodes */
  	/* locks, not used by Linux: */
  	char		s_flock;	/* lock during free block list manipulation */
  	char		s_ilock;	/* lock during inode cache manipulation */
  	char		s_fmod;		/* super-block modified flag */
  	char		s_ronly;	/* flag whether fs is mounted read-only */
  	__fs32		s_time __packed2__; /* time of last super block update */
  	__fs32		s_tfree __packed2__; /* total number of free zones */
  	__fs16		s_tinode;	/* total number of free inodes */
  	__fs16		s_interleave_m;	/* interleave factor */
  	__fs16		s_interleave_n;
  	char		s_fname[6];	/* file system volume name */
  	char		s_fpack[6];	/* file system pack name */
  	__fs32		s_unique;	/* zero, not used */
  };
  
  /* SystemV/Coherent inode data on disk */
  struct sysv_inode {
  	__fs16 i_mode;
  	__fs16 i_nlink;
  	__fs16 i_uid;
  	__fs16 i_gid;
  	__fs32 i_size;
  	u8  i_data[3*(10+1+1+1)];
  	u8  i_gen;
  	__fs32 i_atime;	/* time of last access */
  	__fs32 i_mtime;	/* time of last modification */
  	__fs32 i_ctime;	/* time of creation */
  };
  
  /* SystemV/Coherent directory entry on disk */
  #define SYSV_NAMELEN	14	/* max size of name in struct sysv_dir_entry */
  struct sysv_dir_entry {
  	sysv_ino_t inode;
  	char name[SYSV_NAMELEN]; /* up to 14 characters, the rest are zeroes */
  };
  
  #define SYSV_DIRSIZE	sizeof(struct sysv_dir_entry)	/* size of every directory entry */
  
  #endif /* _LINUX_SYSV_FS_H */