#include "all.h" enum{	MAXWREN = 7,}; static char WMAGIC[] =	"kfs wren device\n";static char MMAGIC[] =	"kfs multi-wren device %4d/%4d\n"; typedef struct Wren	Wren; struct Wren{	QLock;	Device	dev;	ulong	nblocks;	int	fd;}; static char	*wmagic = WMAGIC;static Wren	*wrens;static int	maxwren;char		*wrenfile;int		nwren;int		badmagic; static Wren *wren(Device dev){	int i; 	for(i = 0; i < maxwren; i++)		if(devcmp(dev, wrens[i].dev) == 0)			return &wrens[i];	panic("can't find wren for %D", dev);	return 0;} /* * find out the length of a file * given the mesg version of a stat buffer * we call this because convM2D is different * for the file system than in the os */uvlongstatlen(char *ap){	uchar *p;	ulong ll, hl; 	p = (uchar*)ap;	p += 3*NAMELEN+5*4;	ll = p[0] | (p[1]<<8) | (p[2]<<16) | (p[3]<<24);	hl = p[4] | (p[5]<<8) | (p[6]<<16) | (p[7]<<24);	return ll | ((uvlong) hl << 32);} static voidwrenpartinit(Device dev, int k){	char buf[MAXBUFSIZE], d[DIRREC];	char file[128], magic[64];	Wren *w;	int fd, i, nmagic; 	if(wrens == 0)		wrens = ialloc(MAXWREN * sizeof *wrens);	w = &wrens[maxwren];	if(nwren > 0)		sprint(file, "%s%d", wrenfile, k);	else		strcpy(file, wrenfile);	fd = open(file, ORDWR);	if(fd < 0)		panic("can't open %s", file);	if(fstat(fd, d) < 0)		panic("can't stat %s\n", file);	seek(fd, 0, 0);	i = read(fd, buf, sizeof buf);	if(i < sizeof buf)		panic("can't read %s", file);	badmagic = 0;	RBUFSIZE = 1024;	sprint(magic, wmagic, k, nwren);	nmagic = strlen(magic);	if(strncmp(buf+256, magic, nmagic) == 0){		RBUFSIZE = atol(buf+256+nmagic);		if(RBUFSIZE % 512){			fprint(2, "kfs: bad buffersize(%d): assuming 1k blocks\n", RBUFSIZE);			RBUFSIZE = 1024;		}	}else		badmagic = 1;	w->dev = dev;	w->nblocks = statlen(d)/RBUFSIZE;	if(k > 0)		w->nblocks -= 1;	/* don't count magic */	w->fd = fd;	maxwren++;} voidwreninit(Device dev){	int i; 	if(nwren > 0)		wmagic = MMAGIC;	i = 0;	do{		wrenpartinit(dev, i);	}while(++i < nwren);} static voidwrenpartream(Device dev, int k){	Wren *w;	char buf[MAXBUFSIZE], magic[64];	int fd, i; 	if(RBUFSIZE % 512)		panic("kfs: bad buffersize(%d): restart a multiple of 512\n", RBUFSIZE);	print("kfs: reaming the file system using %d byte blocks\n", RBUFSIZE);	w = wren(dev)+k;	fd = w->fd;	memset(buf, 0, sizeof buf);	sprint(magic, wmagic, k, nwren);	sprint(buf+256, "%s%d\n", magic, RBUFSIZE);	qlock(w);	i = seek(fd, 0, 0) < 0 || write(fd, buf, RBUFSIZE) != RBUFSIZE;	qunlock(w);	if(i < 0)		panic("can't ream disk");} voidwrenream(Device dev){	int i; 	i = 0;	do{		wrenpartream(dev, i);	}while(++i < nwren);} static intwrentag(char *p, int tag, long qpath){	Tag *t; 	t = (Tag*)(p+BUFSIZE);	return t->tag != tag || (qpath&~QPDIR) != t->path;} intwrencheck(Device dev){	char buf[MAXBUFSIZE]; 	if(badmagic)		return 1;	if(RBUFSIZE > sizeof buf)		panic("bufsize too big");	if(wrenread(dev, wrensuper(dev), buf) || wrentag(buf, Tsuper, QPSUPER)	|| wrenread(dev, wrenroot(dev), buf) || wrentag(buf, Tdir, QPROOT))		return 1;	if(((Dentry *)buf)[0].mode & DALLOC)		return 0;	return 1;} longwrensize(Device dev){	Wren *w;	int i, nb; 	w = wren(dev);	nb = 0;	i = 0;	do{		nb += w[i].nblocks;	}while(++i < nwren);	return nb;} longwrensuper(Device dev){	USED(dev);	return 1;} longwrenroot(Device dev){	USED(dev);	return 2;} intwrenread(Device dev, long addr, void *b){	Wren *w;	int fd, i; 	w = wren(dev);	for(i=0; i<nwren; i++){		if(addr < w->nblocks)			break;		addr -= w->nblocks;		++w;	}	if(i > 0)		addr++;	fd = w->fd;	qlock(w);	i = seek(fd, (vlong)addr*RBUFSIZE, 0) == -1 || read(fd, b, RBUFSIZE) != RBUFSIZE;	qunlock(w);	return i;} intwrenwrite(Device dev, long addr, void *b){	Wren *w;	int fd, i; 	w = wren(dev);	for(i=0; i<nwren; i++){		if(addr < w->nblocks)			break;		addr -= w->nblocks;		++w;	}	if(i > 0)		addr++;	fd = w->fd;	qlock(w);	i = seek(fd, (vlong)addr*RBUFSIZE, 0) == -1 || write(fd, b, RBUFSIZE) != RBUFSIZE;	qunlock(w);	return i;}