ref: f0563cbdbce1777d5672fee507acac7ab0d6dbc0
dir: /dat.h/
typedef struct Blk Blk;
typedef struct Gefs Gefs;
typedef struct Fmsg Fmsg;
typedef struct Fid Fid;
typedef struct Msg Msg;
typedef struct Key Key;
typedef struct Val Val;
typedef struct Kvp Kvp;
typedef struct Bptr Bptr;
typedef struct Path Path;
typedef struct Scan Scan;
typedef struct Dent Dent;
typedef struct Scanp Scanp;
typedef struct Arena Arena;
typedef struct Arange Arange;
typedef struct Bucket Bucket;
typedef struct Chan Chan;
enum {
KiB = 1024ULL,
MiB = 1024ULL*KiB,
GiB = 1024ULL*MiB,
TiB = 1024ULL*GiB,
Lgblk = 9,
Blksz = (1ULL<<Lgblk),
Nrefbuf = 1024, /* number of ref incs before syncing */
Nfidtab = 1024, /* number of fit hash entries */
Ndtab = 1024, /* number of dir tab entries */
Max9p = 16*KiB, /* biggest message size we're willing to negotiate */
Nsec = 1000*1000*1000, /* nanoseconds to the second */
Maxname = 256, /* maximum size of a name element */
Maxent = 9+Maxname+1, /* maximum size of ent key, with terminator */
/*
* Kpmax must be no more than 1/4 of pivspc, or
* there is no way to get a valid split of a
* maximally filled tree.
*/
Loghdsz = 8, /* log hash */
Keymax = 32, /* key data limit */
Inlmax = 128, /* inline data limit */
Ptrsz = 18, /* off, hash, fill */
Kvmax = Keymax + Inlmax, /* Key and value */
Kpmax = Keymax + Ptrsz, /* Key and pointer */
Hdrsz = 10,
Blkspc = Blksz - Hdrsz,
Bufspc = Blkspc / 2,
Pivspc = Blkspc - Bufspc,
Logspc = Blkspc - Loghdsz,
Leafspc = Blkspc,
Msgmax = 1 + (Kvmax > Kpmax ? Kvmax : Kpmax)
};
enum {
/*
* dent: pqid[8] qid[8] -- a directory entry key.
* ptr: off[8] hash[8] -- a key for an Dir block.
* dir: fixed statbuf header, user ids
*/
Kref, /* off[8] => ptr[16]: pointer to refcount page */
Kdat, /* qid[8] off[8] => ptr[16]: pointer to data page */
Kent, /* pqid[8] name[n] => dir[n]: serialized Dir */
Ksnap, /* name[n] => dent[16] ptr[16]: snapshot root */
Ksuper, /* qid[8] => pqid[8]: parent dir */
};
enum {
Bdirty = 1 << 0,
Bqueued = 1 << 1,
Bfinal = 1 << 2,
Bcache = 1 << 3,
};
#define Efs "i will not buy this fs, it is scratched"
#define Efid "bad fid"
#define Edscan "invalid dir scan offset"
#define Eexist "does not exist"
#define Ebotch "protocol botch"
#define Emode "unknown mode"
#define Efull "file system full"
#define Eauth "authentication failed"
#define Elength "name too long"
#define Eperm "permission denied"
#define Einuse "resource in use"
#define Ebadf "invalid file"
#define Emem "out of memory"
#define Ename "invalid file name"
#define Enomem "out of memory"
/*
* All metadata blocks share a common header:
*
* type[2]
*
* The None type is reserved for file data blocks
* and refcount blocks.
*
* The superblock has this layout:
* version[8] always "gefs0001"
* flags[4] status flags:
* dirty=1<<0,
* blksz[4] block size in bytes
* bufsz[4] portion of leaf nodes
* allocated to buffers,
* in bytes
* hdrsz[4] size of tree node header,
* in bytes.
* height[4] tree height of root node
* rootb[8] address of root in last
* snapshot.
* rooth[8] hash of root node
* narena[4] number of arenas in tree
* arenasz[8] maximum size of arenas;
* they may be smaller.
* gen[8] The flush generation
*
* The arena zone blocks have this layout, and
* are overwritten in place:
*
* log[8] The head of the alloc log
* logh[8] The hash of the alloc log
*
* The log blocks have this layout, and are one of
* two types of blocks that get overwritten in place:
*
* hash[8] The hash of the previous log block
*
* The remainder of the block is filled with log
* entries. Each log entry has at least 8 bytes
* of entry. Some are longer. The opcode is or'ed
* into the low order bits of the first vlong.
* These ops take the following form:
*
* Alloc, Free:
* off[8] len[8]
* Alloc1, Free1:
* off[8]
* Ref:
* off[8]
* Flush:
* gen[8]
*
* Pivots have the following layout:
*
* nval[2]
* valsz[2]
* nbuf[2]
* bufsz[2]
*
* Leaves have the following layout:
*
* nval[2]
* valsz[2]
* _pad[4]sure,
*
* Within these nodes, pointers have the following
* layout:
*
* off[8] hash[8] fill[2]
*/
enum {
Tnone,
Traw,
Tsuper,
Tarena,
Tlog,
Tpivot,
Tleaf,
};
enum {
Vinl, /* Inline value */
Vref, /* Block pointer */
};
enum {
GBraw = 1<<0,
GBwrite = 1<<1,
};
enum {
Oinsert,
Odelete,
Owstat,
/* wstat flags */
Owsize = 1<<4,
Owname = 1<<5,
Owmode = 1<<6,
Owmtime = 1<<7,
};
/*
* Operations for the allocation log.
*/
enum {
/* 1-wide entries */
LgAlloc1, /* alloc a block */
LgFree1, /* alloc a block */
LgRef, /* ref a block */
LgUnref, /* free a block */
LgFlush, /* flush log, bump gen */
LgChain, /* point to next log block */
LgEnd, /* last entry in log */
/* 2-wide entries */
Lg2w = 1<<5,
LgAlloc = LgAlloc1|Lg2w, /* alloc a range */
LgFree = LgFree1|Lg2w, /* free a range */
};
struct Arange {
Avl;
vlong off;
vlong len;
};
struct Bucket {
Lock;
Blk *b;
};
struct Fmsg {
Fcall;
int fd; /* the fd to repsond on */
QLock *wrlk; /* write lock on fd */
int sz; /* the size of the message buf */
uchar buf[];
};
/*
* Overall state of the file sytem.
* Shadows the superblock contents.
*/
struct Gefs {
int blksz;
int bufsz;
int pivsz;
int hdrsz;
QLock snaplk;
Blk* super;
Chan *wrchan;
Chan *rdchan;
int fd;
long broken;
Lock rootlk;
/* protected by rootlk */
vlong rootb;
vlong rooth;
int height;
Lock genlk;
vlong gen;
Lock qidlk;
vlong nextqid;
Arena *arenas;
int narena;
long nextarena;
vlong arenasz;
Lock fidtablk;
Fid *fidtab[Nfidtab];
Lock dtablk;
Dent *dtab[Ndtab];
Lock lrulk;
/* protected by lrulk */
Bucket *cache;
Blk *chead;
Blk *ctail;
int ccount;
int cmax;
};
struct Arena {
Lock;
Avltree *free;
Avltree *partial;
vlong log; /* log head */
vlong logh; /* log head hash */
Blk *logtl; /* tail block open for writing */
Blk *b; /* arena block */
Blk **q; /* write queue */
vlong nq;
};
struct Key{
char *k;
int nk;
};
struct Val {
int type;
union {
/* block pointer */
struct {
uvlong bp;
uvlong bh;
ushort fill;
};
/* inline values */
struct {
short nv;
char *v;
};
};
};
struct Kvp {
Key;
Val;
};
struct Msg {
char op;
Kvp;
};
struct Dent {
RWLock;
Key;
Dent *next;
long ref;
Qid qid;
vlong length;
vlong rootb;
char buf[Maxent];
};
struct Fid {
Lock;
Fid *next;
/*
* if opened with OEXEC, we want to use a snapshot,
* instead of the most recent root, to prevent
* paging in the wrong executable.
*/
vlong rootb;
vlong rooth;
int height;
u32int fid;
vlong qpath;
int mode;
int iounit;
Scan *scan; /* in progres scan */
Dent *dent; /* (pqid, name) ref, modified on rename */
};
struct Path {
/* Flowing down for flush */
Blk *b; /* insertion */
int idx; /* insert at */
int lo; /* key range */
int hi; /* key range */
int sz; /* size of range */
/* Flowing up from flush */
Blk *l; /* left of split */
Blk *r; /* right of split */
Blk *n; /* shadowed node */
/*
* If we merged or rotated, at least
* one of these nodes is not nil,
* and midx points at the left of
* the two nodes.
*/
Blk *nl; /* merged/rotated left */
Blk *nr; /* merged/rotated right */
int midx; /* merged index */
char split; /* did we split? */
char merge; /* did we merge? */
};
struct Scanp {
int bi;
int vi;
Blk *b;
};
struct Scan {
vlong offset; /* last read offset */
vlong rootb;
vlong rooth;
int height;
int done;
Kvp kv;
Key pfx;
char kvbuf[Kvmax];
char pfxbuf[Keymax];
Scanp *path;
};
struct Blk {
RWLock;
/* cache entry */
Blk *cnext;
Blk *cprev;
Blk *hnext;
short flag;
/* serialized to disk in header */
short type; /* @0, for all */
short nval; /* @2, for Leaf, Pivot: data[0:2] */
short valsz; /* @4, for Leaf, Pivot: data[2:4] */
short nbuf; /* @6, for Pivot */
short bufsz; /* @8, for Pivot */
vlong logsz; /* for allocation log */
vlong lognxt; /* for allocation log */
vlong off; /* -1 for unallocated */
long ref; /* TODO: move out */
char *data;
char buf[Blksz];
};
struct Chan {
int size; /* size of queue */
long count; /* how many in queue (semaphore) */
long avail; /* how many available to send (semaphore) */
Lock rl, wl; /* circular pointers */
void **rp;
void **wp;
void* args[]; /* list of saved pointers, [->size] */
};