/* * minimal definitions of 4BSD `fast file system' format * just enough to read a disk volume */ #define SBLOCK 8192 /* byte offset to (first) super-block */ #define SBSIZE 8192 /* size of super-block */ /* * contents of super-block */ struct fs { struct fs *fs_link; /* linked list of file systems */ struct fs *fs_rlink; /* used for incore super blocks */ long fs_sblkno; /* addr of super-block in filesys */ long fs_cblkno; /* offset of cyl-block in filesys */ long fs_iblkno; /* offset of inode-blocks in filesys */ long fs_dblkno; /* offset of first data after cg */ long fs_cgoffset; /* cylinder group offset in cylinder */ long fs_cgmask; /* used to calc mod fs_ntrak */ long fs_time; /* last time written */ long fs_size; /* number of blocks in fs */ long fs_dsize; /* number of data blocks in fs */ long fs_ncg; /* number of cylinder groups */ long fs_bsize; /* size of basic blocks in fs */ long fs_fsize; /* size of frag blocks in fs */ long fs_frag; /* number of frags in a block in fs */ /* these are configuration parameters */ long fs_minfree; /* minimum percentage of free blocks */ long fs_rotdelay; /* num of ms for optimal next block */ long fs_rps; /* disk revolutions per second */ /* these fields can be computed from the others */ long fs_bmask; /* ``blkoff'' calc of blk offsets */ long fs_fmask; /* ``fragoff'' calc of frag offsets */ long fs_bshift; /* ``lblkno'' calc of logical blkno */ long fs_fshift; /* ``numfrags'' calc number of frags */ /* these are configuration parameters */ long fs_maxcontig; /* max number of contiguous blks */ long fs_maxbpg; /* max number of blks per cyl group */ /* these fields can be computed from the others */ long fs_fragshift; /* block to frag shift */ long fs_fsbtodb; /* fsbtodb and dbtofsb shift constant */ long fs_sbsize; /* actual size of super block */ long fs_csmask; /* csum block offset */ long fs_csshift; /* csum block number */ long fs_nindir; /* value of NINDIR */ long fs_inopb; /* value of INOPB */ long fs_nspf; /* value of NSPF */ long fs_optim; /* optimization preference, see below */ long fs_sparecon[5]; /* reserved for future constants */ /* sizes determined by number of cylinder groups and their sizes */ long fs_csaddr; /* blk addr of cyl grp summary area */ long fs_cssize; /* size of cyl grp summary area */ long fs_cgsize; /* cylinder group size */ /* these fields should be derived from the hardware */ long fs_ntrak; /* tracks per cylinder */ long fs_nsect; /* sectors per track */ long fs_spc; /* sectors per cylinder */ /* this comes from the disk driver partitioning */ long fs_ncyl; /* cylinders in file system */ /* these fields can be computed from the others */ long fs_cpg; /* cylinders per group */ long fs_ipg; /* inodes per group */ long fs_fpg; /* blocks per group * fs_frag */ #if NOTDEF /* what follows isn't interesting */ /* this data must be re-computed after crashes */ struct csum fs_cstotal; /* cylinder summary information */ /* these fields are cleared at mount time */ char fs_fmod; /* super block modified flag */ char fs_clean; /* file system is clean flag */ char fs_ronly; /* mounted read-only flag */ char fs_flags; /* currently unused flag */ char fs_fsmnt[MAXMNTLEN]; /* name mounted on */ /* these fields retain the current block allocation info */ long fs_cgrotor; /* last cg searched */ struct csum *fs_csp[MAXCSBUFS];/* list of fs_cs info buffers */ long fs_cpc; /* cyl per cycle in postbl */ short fs_postbl[MAXCPG][NRPOS];/* head of blocks for each rotation */ long fs_magic; /* magic number */ u_char fs_rotbl[1]; /* list of blocks for each rotation */ /* actually longer */ #endif }; #define INOSIZE 128 /* length of inode on disk */ #define NDADDR 12 #define NIADDR 3 /* * inode on disk */ struct icommon { short i_mode; /* 0: mode and type of file */ short i_nlink; /* 2: number of links to file */ short i_uid; /* 4: owner's user id */ short i_gid; /* 6: owner's group id */ long i_size; /* 8: number of bytes in file */ long i_hisize; /* 12: high part of 64-byte size */ long i_atime; /* 16: time last accessed */ long i_atspare; long i_mtime; /* 24: time last modified */ long i_mtspare; long i_ctime; /* 32: last time inode changed */ long i_ctspare; long i_db[NDADDR]; /* 40: disk block addresses */ long i_ib[NIADDR]; /* 88: indirect blocks */ long i_flags; /* 100: status, currently unused */ long i_blocks; /* 104: blocks actually held */ long i_spare[5]; /* 108: reserved, currently unused */ }; #define ROOTINO 2 /* * directory format */ #define MAXNAMLEN 255 struct direct { long d_ino; /* inode number of entry */ unsigned short d_reclen; /* length of this record */ unsigned short d_namlen; /* length of string in d_name */ char d_name[MAXNAMLEN + 1]; /* name must be no longer than this */ }; #define DIRSIZ(dp) \ ((sizeof (struct direct) - (MAXNAMLEN+1)) + (((dp)->d_namlen+1 + 3) &~ 3))