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#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
*/
uvlong
statlen(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 void
wrenpartinit(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++;
}
void
wreninit(Device dev)
{
int i;
if(nwren > 0)
wmagic = MMAGIC;
i = 0;
do{
wrenpartinit(dev, i);
}while(++i < nwren);
}
static void
wrenpartream(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");
}
void
wrenream(Device dev)
{
int i;
i = 0;
do{
wrenpartream(dev, i);
}while(++i < nwren);
}
static int
wrentag(char *p, int tag, long qpath)
{
Tag *t;
t = (Tag*)(p+BUFSIZE);
return t->tag != tag || (qpath&~QPDIR) != t->path;
}
int
wrencheck(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;
}
long
wrensize(Device dev)
{
Wren *w;
int i, nb;
w = wren(dev);
nb = 0;
i = 0;
do{
nb += w[i].nblocks;
}while(++i < nwren);
return nb;
}
long
wrensuper(Device dev)
{
USED(dev);
return 1;
}
long
wrenroot(Device dev)
{
USED(dev);
return 2;
}
int
wrenread(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;
}
int
wrenwrite(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;
}
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