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#include "all.h"
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enum{
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	MAXWREN = 7,
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};
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#define WMAGIC	"kfs wren device\n"
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typedef struct Wren	Wren;
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struct Wren{
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	QLock;
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	Device	dev;
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	uvlong	size;
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	int	fd;
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};
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static Wren	*wrens;
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static int	maxwren;
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char		*wrenfile;
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int		nwren;
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int		badmagic;
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static Wren *
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wren(Device dev)
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{
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	int i;
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	for(i = 0; i < maxwren; i++)
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		if(devcmp(dev, wrens[i].dev) == 0)
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			return &wrens[i];
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	panic("can't find wren for %D", dev);
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	return 0;
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}
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void
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wreninit(Device dev)
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{
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	char buf[MAXBUFSIZE];
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	Wren *w;
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	Dir *d;
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	int fd, i;
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	if(wrens == 0)
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		wrens = ialloc(MAXWREN * sizeof *wrens);
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	w = &wrens[maxwren];
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	fd = open(wrenfile, ORDWR);
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	if(fd < 0)
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		panic("can't open %s", wrenfile);
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	if((d = dirfstat(fd)) == nil)
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		panic("can't stat %s\n", wrenfile);
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	seek(fd, 0, 0);
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	i = read(fd, buf, sizeof buf);
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	if(i < sizeof buf)
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		panic("can't read %s", wrenfile);
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	badmagic = 0;
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	RBUFSIZE = 1024;
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	if(strncmp(buf+256, WMAGIC, strlen(WMAGIC)) == 0){
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		RBUFSIZE = atol(buf+256+strlen(WMAGIC));
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		if(RBUFSIZE % 512){
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			fprint(2, "kfs: bad buffersize(%d): assuming 1k blocks\n", RBUFSIZE);
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			RBUFSIZE = 1024;
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		}
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	}else
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		badmagic = 1;
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	w->dev = dev;
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	w->size = d->length;
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	free(d);
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	w->fd = fd;
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	maxwren++;
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}
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void
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wrenream(Device dev)
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{
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	Wren *w;
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	char buf[MAXBUFSIZE];
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	int fd, i;
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	if(RBUFSIZE % 512)
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		panic("kfs: bad buffersize(%d): restart a multiple of 512\n", RBUFSIZE);
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	if(RBUFSIZE > sizeof(buf))
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		panic("kfs: bad buffersize(%d): must be at most %d\n", RBUFSIZE, sizeof(buf));
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	print("kfs: reaming the file system using %d byte blocks\n", RBUFSIZE);
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	w = wren(dev);
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	fd = w->fd;
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	memset(buf, 0, sizeof buf);
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	sprint(buf+256, "%s%d\n", WMAGIC, RBUFSIZE);
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	qlock(w);
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	i = seek(fd, 0, 0) < 0 || write(fd, buf, RBUFSIZE) != RBUFSIZE;
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	qunlock(w);
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	if(i < 0)
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		panic("can't ream disk");
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}
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97 
int
98 
wrentag(char *p, int tag, long qpath)
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{
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	Tag *t;
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	t = (Tag*)(p+BUFSIZE);
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	return t->tag != tag || (qpath&~QPDIR) != t->path;
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}
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106 
int
107 
wrencheck(Device dev)
108 
{
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	char buf[MAXBUFSIZE];
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	if(badmagic)
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		return 1;
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	if(RBUFSIZE > sizeof(buf))
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		panic("kfs: bad buffersize(%d): must be at most %d\n", RBUFSIZE, sizeof(buf));
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	if(wrenread(dev, wrensuper(dev), buf) || wrentag(buf, Tsuper, QPSUPER)
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	|| wrenread(dev, wrenroot(dev), buf) || wrentag(buf, Tdir, QPROOT))
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		return 1;
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	if(((Dentry *)buf)[0].mode & DALLOC)
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		return 0;
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	return 1;
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}
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124 
long
125 
wrensize(Device dev)
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{
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	return wren(dev)->size / RBUFSIZE;
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}
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130 
long
131 
wrensuper(Device dev)
132 
{
133 
	USED(dev);
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	return 1;
135 
}
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137 
long
138 
wrenroot(Device dev)
139 
{
140 
	USED(dev);
141 
	return 2;
142 
}
143 
 
144 
int
145 
wrenread(Device dev, long addr, void *b)
146 
{
147 
	Wren *w;
148 
	int fd, i;
149 
 
150 
	w = wren(dev);
151 
	fd = w->fd;
152 
	qlock(w);
153 
	i = seek(fd, (vlong)addr*RBUFSIZE, 0) == -1 || read(fd, b, RBUFSIZE) != RBUFSIZE;
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	qunlock(w);
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	if(i)
156 
		print("wrenread failed: %r\n");
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	return i;
158 
}
159 
 
160 
int
161 
wrenwrite(Device dev, long addr, void *b)
162 
{
163 
	Wren *w;
164 
	int fd, i;
165 
 
166 
	w = wren(dev);
167 
	fd = w->fd;
168 
	qlock(w);
169 
	i = seek(fd, (vlong)addr*RBUFSIZE, 0) == -1 || write(fd, b, RBUFSIZE) != RBUFSIZE;
170 
	qunlock(w);
171 
	if(i)
172 
		print("wrenwrite failed: %r\n");
173 
	return i;
174 
}