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Diffstat (limited to 'src/libdiskfs/ffs.h')
| -rw-r--r-- | src/libdiskfs/ffs.h | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/src/libdiskfs/ffs.h b/src/libdiskfs/ffs.h new file mode 100644 index 00000000..479ff65f --- /dev/null +++ b/src/libdiskfs/ffs.h @@ -0,0 +1,281 @@ +/* + * An FFS file system is a sequence of cylinder groups. + * + * Each cylinder group is laid out as follows: + * + * fs superblock (Fsblk) + * cylinder group block (Cgblk) + * inodes + * data + * + * The location of the fs superblock in the first cylinder + * group is known. The rest of the info about cylinder group + * layout can be derived from the super block. + */ + +#define daddr_t u32int +#define time_t u32int + +typedef struct Cgblk Cgblk; +typedef struct Cylgrp Cylgrp; +typedef struct Cylsum Cylsum; +typedef struct Ffs Ffs; +typedef struct Fsblk Fsblk; +typedef struct Inode Inode; +typedef struct Dirent Dirent; + +enum +{ + BYTESPERSEC = 512, + + /* constants for Fsblk */ + FSMAXMNTLEN = 512, + FSNOCSPTRS = 128 / sizeof(void*) - 3, + FSMAXSNAP = 20, + FSMAGIC = 0x011954, + FSCHECKSUM = 0x7c269d38, + + /* Fsblk.inodefmt */ + FS42INODEFMT = -1, + FS44INODEFMT = 2, + + /* offset and size of first boot block */ + BBOFF = 0, + BBSIZE = 8192, + + /* offset and size of first super block */ + SBOFF = BBOFF+BBSIZE, + SBSIZE = 8192, + + /* minimum block size */ + MINBSIZE = 4096, + + /* maximum fragments per block */ + MAXFRAG = 8, + + /* constants for Cgblk */ + CGMAGIC = 0x090255, + + /* inode-related */ + ROOTINODE = 2, + WHITEOUT = 1, + + NDADDR = 12, + NIADDR = 3, + + /* permissions in Inode.mode */ + IEXEC = 00100, + IWRITE = 0200, + IREAD = 0400, + ISVTX = 01000, + ISGID = 02000, + ISUID = 04000, + + /* type in Inode.mode */ + IFMT = 0170000, + IFIFO = 0010000, + IFCHR = 0020000, + IFDIR = 0040000, + IFBLK = 0060000, + IFREG = 0100000, + IFLNK = 0120000, + IFSOCK = 0140000, + IFWHT = 0160000, + + /* type in Dirent.type */ + DTUNKNOWN = 0, + DTFIFO = 1, + DTCHR = 2, + DTDIR = 4, + DTBLK = 6, + DTREG = 8, + DTLNK = 10, + DTSOCK = 12, + DTWHT = 14, +}; + +struct Cylsum +{ + u32int ndir; + u32int nbfree; + u32int nifree; + u32int nffree; +}; + +struct Fsblk +{ + u32int unused0; + u32int unused1; + daddr_t sfragno; /* fragment address of super block in file system */ + daddr_t cfragno; /* fragment address if cylinder block in file system */ + daddr_t ifragno; /* fragment offset of inode blocks in file system */ + daddr_t dfragno; /* fragment offset of data blocks in cg */ + u32int cgoffset; /* block (maybe fragment?) offset of Cgblk in cylinder */ + u32int cgmask; + time_t time; + u32int nfrag; /* number of blocks in fs * fragsperblock */ + u32int ndfrag; + u32int ncg; /* number of cylinder groups in fs */ + u32int blocksize; /* block size in fs */ + u32int fragsize; /* frag size in fs */ + u32int fragsperblock; /* fragments per block: blocksize / fragsize */ + u32int minfree; /* ignored by us */ + u32int rotdelay; /* ... */ + u32int rps; + u32int bmask; + u32int fmask; + u32int bshift; + u32int fshift; + u32int maxcontig; + u32int maxbpg; + u32int fragshift; + u32int fsbtodbshift; + u32int sbsize; /* size of super block */ + u32int unused2; /* more stuff we don't use ... */ + u32int unused3; + u32int nindir; + u32int inosperblock; /* inodes per block */ + u32int nspf; + u32int optim; + u32int npsect; + u32int interleave; + u32int trackskew; + u32int id[2]; + daddr_t csaddr; /* blk addr of cyl grp summary area */ + u32int cssize; /* size of cyl grp summary area */ + u32int cgsize; /* cylinder group size */ + u32int trackspercyl; /* tracks per cylinder */ + u32int secspertrack; /* sectors per track */ + u32int secspercyl; /* sectors per cylinder */ + u32int ncyl; /* cylinders in fs */ + u32int cylspergroup; /* cylinders per group */ + u32int inospergroup; /* inodes per group */ + u32int fragspergroup; /* data blocks per group * fragperblock */ + Cylsum cstotal; /* more unused... */ + u8int fmod; + u8int clean; + u8int ronly; + u8int flags; + char fsmnt[FSMAXMNTLEN]; + u32int cgrotor; + void* ocsp[FSNOCSPTRS]; + u8int* contigdirs; + Cylsum* csp; + u32int* maxcluster; + u32int cpc; + u16int opostbl[16][8]; + u32int snapinum[FSMAXSNAP]; + u32int avgfilesize; + u32int avgfpdir; + u32int sparecon[26]; + u32int pendingblocks; + u32int pendinginodes; + u32int contigsumsize; + u32int maxsymlinklen; + u32int inodefmt; /* format of on-disk inodes */ + u64int maxfilesize; /* maximum representable file size */ + u64int qbmask; + u64int qfmask; + u32int state; + u32int postblformat; + u32int nrpos; + u32int postbloff; + u32int rotbloff; + u32int magic; /* FS_MAGIC */ +}; + +/* + * Cylinder group block for a file system. + */ +struct Cgblk +{ + u32int unused0; + u32int magic; /* CGMAGIC */ + u32int time; /* time last written */ + u32int num; /* we are cg #cgnum */ + u16int ncyl; /* number of cylinders in gp */ + u16int nino; /* number of inodes */ + u32int nfrag; /* number of fragments */ + Cylsum csum; + u32int rotor; + u32int frotor; + u32int irotor; + u32int frsum[MAXFRAG]; /* counts of available frags */ + u32int btotoff; + u32int boff; + u32int imapoff; /* offset to used inode map */ + u32int fmapoff; /* offset to free fragment map */ + u32int nextfrag; /* next free fragment */ + u32int csumoff; + u32int clusteroff; + u32int ncluster; + u32int sparecon[13]; +}; + +struct Cylgrp +{ + /* these are block numbers not fragment numbers */ + u32int bno; /* disk block address of start of cg */ + u32int ibno; /* disk block address of first inode */ + u32int dbno; /* disk block address of first data */ + u32int cgblkno; +}; + +/* + * this is the on-disk structure + */ +struct Inode +{ + u16int mode; + u16int nlink; + u32int unused; + u64int size; + u32int atime; + u32int atimensec; + u32int mtime; + u32int mtimensec; + u32int ctime; + u32int ctimensec; + /* rdev is db[0] */ + u32int db[NDADDR]; + u32int ib[NIADDR]; + u32int flags; + u32int nblock; + u32int gen; + u32int uid; + u32int gid; + u32int spare[2]; +}; + +struct Dirent +{ + u32int ino; + u16int reclen; + u8int type; + u8int namlen; + char name[1]; +}; + +/* + * main file system structure + */ +struct Ffs +{ + int blocksize; + int nblock; + int fragsize; + int fragsperblock; + int inosperblock; + int blockspergroup; + int fragspergroup; + int inospergroup; + + u32int nfrag; + u32int ndfrag; + + int ncg; + Cylgrp *cg; + + Disk *disk; +}; + |