ref: fb53d7e68bcb2108fb304c81dccb1d7ff50ffa1f
dir: /dat.h/
typedef signed char s8;
typedef signed short s16;
typedef signed int s32;
typedef signed long long s64;
typedef unsigned char u8;
typedef unsigned short u16;
typedef unsigned int u32;
typedef unsigned long long u64;
typedef struct Config Config;
typedef struct Data Data;
typedef struct Metadata Metadata;
typedef struct Metadataunit Metadataunit;
typedef struct Dentryhdr Dentryhdr;
typedef struct Dentry Dentry;
typedef struct Datahdr Datahdr;
typedef struct Indirect Indirect;
typedef struct Super Super;
typedef struct Tlock Tlock;
typedef struct User User;
typedef struct Aux Aux;
enum
{
KiB = 1024ULL, /* Kibibytes */
MiB = KiB*KiB, /* Mibibytes */
GiB = KiB*MiB, /* Gibibytes */
TiB = KiB*GiB, /* Tibibytes */
Ngroups = 32, /* maximum number of groups an user can belong to */
None = 0, /* user ID for "none" */
Noworld = 9999, /* conventional id for "noworld" group */
Userlen = 32,
Nsec = 1000ULL*1000*1000,
Usec = 1000ULL*1000,
Msec = 1000ULL,
Nbkp = 1,
Nrefresh = 3*Nsec,
};
/*
* fundamental constants and types of the implementation
* changing any of these changes the layout on disk
* The very first block (index = 0) has the magic written at offset 256.
*
* Trying to keep the Qpath the same as the directory entry block number
* for the system files to help me identify numbers easily.
*
* derived constants
* Nindperblock number of block pointers in a block
*/
enum {
Blocksize = 512ULL, /* minimum data unit size */
Metadataunits = 2,
Metadatablocksize = Metadataunits*Blocksize, /* Keep the original and a copy together */
Maxdatablockunits = 2048,
Nindperblock= (Blocksize-3*sizeof(u64))/sizeof(u64),/* number of pointers per block */
Nu64perblock= (Blocksize/sizeof(u64)), /* number of u64's in a block */
Dpathidx = (Blocksize/sizeof(u64) -1), /* index of path in the last data block, last u64 */
Namelen = 127, /* maximum length of a file name, calculated manually */
Ndblock = 32, /* number of direct blocks in a Dentry */
Niblock = 5, /* maximum depth of indirect blocks, can increase it to 8 without issues */
/* global block numbers. The bkp contents locations are calculated by ream() */
Bdmagic = 0, /* block number of first block. Bmagic conflicts with bio.h */
Bdconfig= 2, /* block number of /adm/config dentry and contents */
Bdsuper = 4, /* block number of /adm/super dentry and contents */
Bdadm = 6, /* block number of /adm directory */
Bdusers = 8, /* block number of /adm/users/ dentry */
/* contents of blocks below change on use */
Bdbkp = 10, /* block number of /adm/bkp directory */
Bdusersinuse = 12, /* block number of /adm/users/inuse dentry and contents */
Bdfrees = 14, /* block number of /adm/frees dentry, text file of free extents */
/* no user writes allowed on blocks below Bdctl */
Bdctl = 16, /* block number of /adm/ctl dentry, empty contents, virtual file */
Bdusersstaging = 18,/* block number of /adm/users/staging dentry */
Bdroot = 20, /* block number of root directory */
Nbused = Bdroot+2, /* blocks used up by default */
/* number of blocks used by the above and the backup blocks */
Nminblocks = Nbused+(Metadataunits*Nbkp*3),
/* Qpnone is the Tag.path of free blocks/extents(Tfree),
and zero'ed out dentry blocks */
Qpnone = 0,
Qpconfig = Bdconfig, /* /adm/config block Tag.qpath */
Qpsuper = Bdsuper, /* /adm/super block Tag.qpath */
Qpadm = Bdadm, /* /adm */
Qpusers = Bdusers, /* /adm/users block Tag.qpath */
Qpbkp = Bdbkp, /* /adm/bkp block Tag.qpath */
Qpusersinuse = Bdusersinuse, /* /adm/users/inuse block Tag.qpath */
Qpfrees = Bdfrees, /* /adm/frees block Tag.qpath */
Qpctl = Bdctl, /* /adm/ctl */
Qpusersstaging = Bdusersstaging,/* /adm/users/staging block Tag.qpath */
Qproot = Bdroot, /* /, so fscreate() can disallow any create's below */
/* system qpaths */
Qpmagic = 1, /* magic block Tag.qpath */
Qpconfig0 = 3, /* /adm/bkp/config.0 block Tag.qpath */
Qpsuper0 = 5, /* /adm/bkp/super.0 block Tag.qpath */
Qproot0 = 21, /* /adm/bkp/root.0 block Tag.qpath */
Nqidgen = 64,
/* check qpath for overflows - TODO, should be 2^64 */
Maxqpath = 72057594037927936ULL, /* 2^56 */
Nthdirty = 9, /* dirty byte is the 9th byte in the Tag */
};
#pragma pack on
/* DONT TOUCH, this is the disk structure */
/* no access time */
struct Dentryhdr
{
u8 tag;
u8 verd;
s16 uid;
s16 gid;
s16 muid; /* 8 */
u64 size; /* 0 for directories. For files, size in bytes of the content - 16 */
u64 pdblkno; /* block number of the parent directory entry. Will be 0 for root. - 24 */
u64 pqpath; /* parent qid.path - 32 */
u64 mtime; /* modified time in nano seconds from epoch - 40 */
u64 qpath; /* unique identifier Qid.path 48 */
u32 version; /* Qid.version 52 */
u32 mode; /* same bits as defined in /sys/include/libc.h:/Dir\.mode/ - 56 */
u8 namelen; /* store name as a counted string 57 */
s8 name[Namelen]; /* Namelen = 127 - 184*/
};
struct Datahdr
{
u8 tag;
u8 unused; /* for alignment and future use */
u16 len;
u64 dblkno; /* block number of the directory entry */
};
#pragma pack off
enum {
/* size of identifiers used in a Tdata block */
Ddataidssize = sizeof(Datahdr) +sizeof(u64 /* trailing path */),
/* max possible size of data that can be stuffed into a Dentry */
Ddatasize = Blocksize -sizeof(Dentryhdr) -sizeof(u64 /* trailing path */),
Maxdatablocksize = Maxdatablockunits*Blocksize -Ddataidssize,
};
#pragma pack on
/* DONT TOUCH, these are all disk structures */
struct Super
{
u64 qidgen; /* generator for unique ids. starts from 1024. */
/* TODO make fsok a time stamp in nano seconds */
u64 fsok; /* fsck status, using 64 bits to keep it all aligned */
};
struct Dentry
{
Dentryhdr;
union
{
struct
{
u64 dblocks[Ndblock]; /* direct blocks. */
/* List of Tdata block numbers for files and
Tdentry block numbers for directories */
u64 iblocks[Niblock]; /* indirect blocks */
};
Super;
/* when size <= Dentrysize-184-sizeof(Tag), store the data here itself */
s8 buf[Ddatasize];
};
u64 path; /* same as qid.path */
};
struct Indirect
{
u8 tagi; /* the suffix i to avoid union complaining about ambiguous fields */
u8 veri;
u8 pad[6]; /* unused, to align to a multiple of 8 */
u64 dblkno; /* block number of the directory entry */
u64 bufa[Nindperblock];
u64 path; /* same as qid.path */
};
struct Metadataunit
{
union
{
Indirect;
Dentry;
};
};
struct Metadata
{
union
{
Indirect i[2];
Dentry d[2];
};
};
struct Data /* used to unmarshall the disk contents */
{
Datahdr;
u8 buf[1]; /* upto Maxdatablocksize, followed by u64 qid.path */
/* u64 path; same as qid.path at the end of the data content - check consistency */
};
#pragma pack off
/*
* array of qids that are locked
*/
struct Tlock
{
u64 time;
u64 qpath;
u64 dblkno;
Tlock *prev, *next;
};
struct Aux
{
u64 dblkno; /* dentry absolute block number */
u16 uid;
u8 tlocked; /* for exclusive use files, flag to indicate lock */
u64 dri; /* directory index while reading a directory */
/* u64 lastreadahead; TODO */
};
/*
every user is also a group with one user.
*/
struct User
{
s16 id; /* user id */
s16 lid; /* id of the leader of group */
char name[Userlen]; /* user name */
s16 *members;/* list of member id's belonging to this group */
int nmembers;/* number of members in this group */
int nalloc; /* allocated space members */
User *prev, *next; /* linked list sorted by id */
};
/* storing this in ascii to the Bdconfig block */
struct Bkp
{
u64 srcbno; /* source of the backup */
u64 dest[Nbkp]; /* destinations written to */
};
struct Config
{
u64 size; /* size from dirfstat */
u64 nblocks; /* size in blocks */
struct Bkp config;
struct Bkp super;
struct Bkp root;
char service[Namelen];
};
enum
{
Nworks = 1024, /* make this a parameter? */
Nworkers = 8 /* 32 */, /* make this a parameter? */
Nlru = 32,
Nuserserrmsg = 64,
};
/*
* error codes generated from the file server
*/
enum
{
Eaccess = 1,
Ealloc,
Eauth,
Eauthmsg,
Ebadname,
Ebadspc,
Ebadu,
Ebroken,
Echar,
Econvert,
Ecount,
Edir1,
Edir2,
Edirty,
Edot,
Eempty,
Eentry,
Eexist,
Efid,
Efidinuse,
Efull,
Einval,
Elocked,
Emode,
Ename,
Enomem,
Enotd,
Enotdir,
Enotg,
Enotl,
Enotm,
Enotu,
Enotw,
Eoffset,
Eopen,
Eperm,
Ephase,
Eqid,
Eqidmode,
Eronly,
Ersc,
Eshutdown,
Esystem,
Etoolong,
Einvusers,
Enousers,
Ewalk,
MAXERR
};
/*
* tags on block
*/
/* DONT TOUCH, this is in disk structures */
/* the first 512 bytes holds the magic.
Not bothering with a tag for 1 Unit. Use Tdentry for that.
*/
/* also, the order from Tdata to Tmaxind is exploited in indirck() & isdirty() */
enum
{
Tblank = 0,
Tfree = 0, /* free block */
Tnone = 0,
Tdata, /* actual file contents */
Tdentry, /* directory entry, size = Dentrysize */
/* Tdata & indirect blocks are last, to allow for greater depth */
Tind0, /* contains a list of Tdata block numbers for files
and Tdentry block numbers for directories.*/
Tind1, /* contains a list of Tind0 block numbers */
Tind2, /* contains a list of Tind1 block numbers */
Tind3, /* contains a list of Tind1 block numbers */
Tind4, /* contains a list of Tind1 block numbers */
/* gap for more indirect block depth in future.
It can be put upto Tind7 without needing any code changes */
Maxtind, /* should be Tind0+Niblock */
MAXTAG = Maxtind,
Tmaxind = Maxtind - 1,
};
/*
* flags to getbuf
*/
enum
{
Breadonly = 1,/* read the block, cannot write to it */
Bwritable = 0,
Bfreshalloc = 1,/* newly allocated block, no contents on the disk */
Bused = 0,/* has contents on the disk */
};
#define SECOND(n) (n)
#define MINUTE(n) (n*SECOND(60))
#define HOUR(n) (n*MINUTE(60))
#define DAY(n) (n*HOUR(24))
#define TLOCK MINUTE(5)
extern char* errstring[MAXERR];
extern char service[Namelen];
extern char *tagnames[];
extern char *devfile; /* device file path */
extern int devfd ; /* device fd */
extern int writeallow;
extern int wstatallow;
extern int allownone;
extern u8 readonly;
extern u8 shuttingdown;
extern u8 noauth;
/* used by panic() */
extern char *procname;
extern Config config;
extern char userserrmsg[Nuserserrmsg];
Config *parseconfig(s8 *cfg, Config *c);