ref: c07ad86666257eb54db8723b330d289b13036d44
dir: /utils/ftl/ftl.c/
/*
* basic Flash Translation Layer driver
* see for instance the Intel technical paper
* ``Understanding the Flash Translation Layer (FTL) Specification''
* Order number 297816-001 (online at www.intel.com)
*
* a public driver by David Hinds, dhinds@allegro.stanford.edu
* further helps with some details.
*
* this driver uses the common simplification of never storing
* the VBM on the medium (a waste of precious flash!) but
* rather building it on the fly as the block maps are read.
*
* Plan 9 driver (c) 1997 by C H Forsyth (forsyth@caldo.demon.co.uk)
* This driver may be used or adapted by anyone for any non-commercial purpose.
*
* adapted for Inferno 1998 by C H Forsyth, Vita Nuova Limited, York, England (charles@vitanuova.com)
*
* C H Forsyth and Vita Nuova Limited expressly allow Lucent Technologies
* to use this driver freely for any Inferno-related purposes whatever,
* including commercial applications.
*
* TO DO:
* check error handling details for get/put flash
* bad block handling
* reserved space in formatted size
* possibly block size as parameter
* fetch parameters from header on init
*
* Adapted to a ftl formatter for Inferno 2000 by J R Firth, Vita Nuova Limited
* usage : ftl flashsize secsize inputfile outputfile
* outputfile will then be a ftl image of inputfile
* nb assumes the base address is zero
*
*/
#include <lib9.h>
ulong flashsize, secsize;
char *flashm;
int trace = 0;
#ifndef offsetof
#define offsetof(T,X) ((ulong)&(((T*)0)->X))
#endif
typedef struct Ftl Ftl;
typedef struct Merase Merase;
typedef struct Terase Terase;
enum {
Eshift = 18, /* 2^18=256k; log2(eraseunit) */
Flashseg = 1<<Eshift,
Bshift = 9, /* 2^9=512 */
Bsize = 1<<Bshift,
BAMoffset = 0x100,
Nolimit = ~0,
USABLEPCT = 95, /* release only this % to client */
FTLDEBUG = 0
};
/* erase unit header (defined by FTL specification) */
struct Merase {
uchar linktuple[5];
uchar orgtuple[10];
uchar nxfer;
uchar nerase[4];
uchar id[2];
uchar bshift;
uchar eshift;
uchar pstart[2];
uchar nunits[2];
uchar psize[4];
uchar vbmbase[4];
uchar nvbm[2];
uchar flags;
uchar code;
uchar serial[4];
uchar altoffset[4];
uchar bamoffset[4];
uchar rsv2[12];
};
#define ERASEHDRLEN 64
enum {
/* special unit IDs */
XferID = 0xffff,
XferBusy = 0x7fff,
/* special BAM addresses */
Bfree = 0xffffffff,
Bwriting = 0xfffffffe,
Bdeleted = 0,
/* block types */
TypeShift = 7,
BlockType = (1<<TypeShift)-1,
ControlBlock = 0x30,
DataBlock = 0x40,
ReplacePage = 0x60,
BadBlock = 0x70,
};
#define BTYPE(b) ((b) & BlockType)
#define BADDR(b) ((b) & ~BlockType)
#define BNO(va) (((ulong)(va))>>Bshift)
#define MKBAM(b,t) (((b)<<Bshift)|(t))
struct Terase {
int x;
int id;
ulong offset;
ulong bamoffset;
ulong nbam;
ulong* bam;
ulong bamx;
ulong nfree;
ulong nused;
ulong ndead;
ulong nbad;
ulong nerase;
};
struct Ftl {
ulong base; /* base of flash region */
ulong size; /* size of flash region */
ulong segsize; /* size of flash segment (erase unit) */
int eshift; /* log2(erase-unit-size) */
int bshift; /* log2(bsize) */
int bsize;
int nunit; /* number of segments (erase units) */
Terase** unit;
int lastx; /* index in unit of last allocation */
int xfer; /* index in unit of current transfer unit (-1 if none) */
ulong nfree; /* total free space in blocks */
ulong nblock; /* total space in blocks */
ulong rwlimit; /* user-visible block limit (`formatted size') */
ulong* vbm; /* virtual block map */
ulong fstart; /* address of first block of data in a segment */
int trace; /* (debugging) trace of read/write actions */
int detach; /* free Ftl on last close */
/* scavenging variables */
int needspace;
int hasproc;
};
enum {
/* Ftl.detach */
Detached = 1, /* detach on close */
Deferred /* scavenger must free it */
};
/* little endian */
#define GET2(p) (((p)[1]<<8)|(p)[0])
#define GET4(p) (((((((p)[3]<<8)|(p)[2])<<8)|(p)[1])<<8)|(p)[0])
#define PUT2(p,v) (((p)[1]=(v)>>8),((p)[0]=(v)))
#define PUT4(p,v) (((p)[3]=(v)>>24),((p)[2]=(v)>>16),((p)[1]=(v)>>8),((p)[0]=(v)))
static Ftl *ftls;
static ulong allocblk(Ftl*);
static void eraseflash(Ftl*, ulong);
static void erasefree(Terase*);
static void eraseinit(Ftl*, ulong, int, int);
static Terase* eraseload(Ftl*, int, ulong);
static void ftlfree(Ftl*);
static void getflash(Ftl*, void*, ulong, long);
static int mapblk(Ftl*, ulong, Terase**, ulong*);
static Ftl* mkftl(char*, ulong, ulong, int, char*);
static void putbam(Ftl*, Terase*, int, ulong);
static void putflash(Ftl*, ulong, void*, long);
static int scavenge(Ftl*);
static void
ftlstat(int sz)
{
print("0x%lux:0x%ux:0x%lux\n", ftls->rwlimit*Bsize, sz, flashsize);
print("%lud:%d:%lud in 512b blocks\n", ftls->rwlimit, sz>>Bshift, flashsize>>Bshift);
}
static long
ftlread(void *buf, long n, ulong offset)
{
Ftl *ftl;
Terase *e;
int nb;
uchar *a;
ulong pb;
if(n <= 0 || n%Bsize || offset%Bsize) {
fprint(2, "bad read\n");
exits("1");
}
ftl = ftls;
nb = n/Bsize;
offset /= Bsize;
if(offset >= ftl->rwlimit)
return 0;
if(offset+nb > ftl->rwlimit)
nb = ftl->rwlimit - offset;
a = buf;
for(n = 0; n < nb; n++){
if(mapblk(ftl, offset+n, &e, &pb))
getflash(ftl, a, e->offset + pb*Bsize, Bsize);
else
memset(a, 0, Bsize);
a += Bsize;
}
return a-(uchar*)buf;
/* not reached */
}
static long
ftlwrite(void *buf, long n, ulong offset)
{
int ns, nb;
uchar *a;
Terase *e, *oe;
ulong ob, v;
Ftl *ftl;
if(n <= 0)
return 0;
ftl = ftls;
if(n <= 0 || n%Bsize || offset%Bsize) {
fprint(2, "bad write\n");
exits("1");
}
nb = n/Bsize;
offset /= Bsize;
if(offset >= ftl->rwlimit)
return 0;
if(offset+nb > ftl->rwlimit)
nb = ftl->rwlimit - offset;
a = buf;
for(n = 0; n < nb; n++){
ns = 0;
while((v = allocblk(ftl)) == 0)
if(!scavenge(ftl) || ++ns > 3){
print("ftl: flash memory full\n");
}
if(!mapblk(ftl, offset+n, &oe, &ob))
oe = nil;
e = ftl->unit[v>>16];
v &= 0xffff;
putflash(ftl, e->offset + v*Bsize, a, Bsize);
putbam(ftl, e, v, MKBAM(offset+n, DataBlock));
/* both old and new block references exist in this window (can't be closed?) */
ftl->vbm[offset+n] = (e->x<<16) | v;
if(oe != nil){
putbam(ftl, oe, ob, Bdeleted);
oe->ndead++;
}
a += Bsize;
}
return a-(uchar*)buf;
/* not reached */
}
static Ftl *
mkftl(char *fname, ulong base, ulong size, int eshift, char *op)
{
int i, j, nov, segblocks;
ulong limit;
Terase *e;
Ftl *ftl;
ftl = malloc(sizeof(*ftl));
if(ftl == nil) {
fprint(2, "out of memory\n");
exits("1");
}
ftl->lastx = 0;
ftl->detach = 0;
ftl->needspace = 0;
ftl->hasproc = 0;
ftl->trace = 0;
limit = flashsize;
if(size == Nolimit)
size = limit-base;
if(base >= limit || size > limit || base+size > limit || eshift < 8 || (1<<eshift) > size) {
fprint(2, "bad flash space parameters");
exits("1");
}
if(FTLDEBUG || ftl->trace || trace)
print("%s flash %s #%lux:#%lux limit #%lux\n", op, fname, base, size, limit);
ftl->base = base;
ftl->size = size;
ftl->bshift = Bshift;
ftl->bsize = Bsize;
ftl->eshift = eshift;
ftl->segsize = 1<<eshift;
ftl->nunit = size>>eshift;
nov = ((ftl->segsize/Bsize)*4 + BAMoffset + Bsize - 1)/Bsize; /* number of overhead blocks per segment (header, and BAM itself) */
ftl->fstart = nov;
segblocks = ftl->segsize/Bsize - nov;
ftl->nblock = ftl->nunit*segblocks;
if(ftl->nblock >= 0x10000)
ftl->nblock = 0x10000;
ftl->vbm = malloc(ftl->nblock*sizeof(*ftl->vbm));
ftl->unit = malloc(ftl->nunit*sizeof(*ftl->unit));
if(ftl->vbm == nil || ftl->unit == nil) {
fprint(2, "out of mem");
exits("1");
}
for(i=0; i<ftl->nblock; i++)
ftl->vbm[i] = 0;
if(strcmp(op, "format") == 0){
for(i=0; i<ftl->nunit-1; i++)
eraseinit(ftl, i*ftl->segsize, i, 1);
eraseinit(ftl, i*ftl->segsize, XferID, 1);
}
ftl->xfer = -1;
for(i=0; i<ftl->nunit; i++){
e = eraseload(ftl, i, i*ftl->segsize);
if(e == nil){
print("ftl: logical segment %d: bad format\n", i);
continue;
}
if(e->id == XferBusy){
e->nerase++;
eraseinit(ftl, e->offset, XferID, e->nerase);
e->id = XferID;
}
for(j=0; j<ftl->nunit; j++)
if(ftl->unit[j] != nil && ftl->unit[j]->id == e->id){
print("ftl: duplicate erase unit #%x\n", e->id);
erasefree(e);
e = nil;
break;
}
if(e){
ftl->unit[e->x] = e;
if(e->id == XferID)
ftl->xfer = e->x;
if (FTLDEBUG || ftl->trace || trace)
print("ftl: unit %d:#%x used %lud free %lud dead %lud bad %lud nerase %lud\n",
e->x, e->id, e->nused, e->nfree, e->ndead, e->nbad, e->nerase);
}
}
if(ftl->xfer < 0 && ftl->nunit <= 0 || ftl->xfer >= 0 && ftl->nunit <= 1) {
fprint(2, "no valid flash data units");
exits("1");
}
if(ftl->xfer < 0)
print("ftl: no transfer unit: device is WORM\n");
else
ftl->nblock -= segblocks; /* discount transfer segment */
if(ftl->nblock >= 1000)
ftl->rwlimit = ftl->nblock-100; /* TO DO: variable reserve */
else
ftl->rwlimit = ftl->nblock*USABLEPCT/100;
return ftl;
}
static void
ftlfree(Ftl *ftl)
{
if(ftl != nil){
free(ftl->unit);
free(ftl->vbm);
free(ftl);
}
}
/*
* this simple greedy algorithm weighted by nerase does seem to lead
* to even wear of erase units (cf. the eNVy file system)
*/
static Terase *
bestcopy(Ftl *ftl)
{
Terase *e, *be;
int i;
be = nil;
for(i=0; i<ftl->nunit; i++)
if((e = ftl->unit[i]) != nil && e->id != XferID && e->id != XferBusy && e->ndead+e->nbad &&
(be == nil || e->nerase <= be->nerase && e->ndead >= be->ndead))
be = e;
return be;
}
static int
copyunit(Ftl *ftl, Terase *from, Terase *to)
{
int i, nb;
uchar id[2];
ulong *bam;
uchar *buf;
ulong v, bno;
if(FTLDEBUG || ftl->trace || trace)
print("ftl: copying %d (#%lux) to #%lux\n", from->id, from->offset, to->offset);
to->nbam = 0;
free(to->bam);
to->bam = nil;
buf = malloc(Bsize);
if(buf == nil)
return 0;
PUT2(id, XferBusy);
putflash(ftl, to->offset+offsetof(Merase,id[0]), id, 2);
/* make new BAM */
nb = from->nbam*sizeof(*to->bam);
bam = malloc(nb);
if(bam == nil) {
fprint(2, "nomem\n");
exits("1");
}
memmove(bam, from->bam, nb);
to->nused = 0;
to->nbad = 0;
to->nfree = 0;
to->ndead = 0;
for(i = 0; i < from->nbam; i++)
switch(bam[i]){
case Bwriting:
case Bdeleted:
case Bfree:
bam[i] = Bfree;
to->nfree++;
break;
default:
switch(bam[i]&BlockType){
default:
case BadBlock: /* it isn't necessarily bad in this unit */
to->nfree++;
bam[i] = Bfree;
break;
case DataBlock:
case ReplacePage:
v = bam[i];
bno = BNO(v & ~BlockType);
if(i < ftl->fstart || bno >= ftl->nblock){
print("ftl: unit %d:#%x bad bam[%d]=#%lux\n", from->x, from->id, i, v);
to->nfree++;
bam[i] = Bfree;
break;
}
getflash(ftl, buf, from->offset+i*Bsize, Bsize);
putflash(ftl, to->offset+i*Bsize, buf, Bsize);
to->nused++;
break;
case ControlBlock:
to->nused++;
break;
}
}
for(i=0; i<from->nbam; i++){
uchar *p = (uchar*)&bam[i];
v = bam[i];
if(v != Bfree && ftl->trace > 1)
print("to[%d]=#%lux\n", i, v);
PUT4(p, v);
}
putflash(ftl, to->bamoffset, bam, nb); /* BUG: PUT4 */
for(i=0; i<from->nbam; i++){
uchar *p = (uchar*)&bam[i];
v = bam[i];
PUT4(p, v);
}
to->id = from->id;
PUT2(id, to->id);
putflash(ftl, to->offset+offsetof(Merase,id[0]), id, 2);
to->nbam = from->nbam;
to->bam = bam;
ftl->nfree += to->nfree - from->nfree;
free(buf);
return 1;
}
static int
mustscavenge(void *a)
{
return ((Ftl*)a)->needspace || ((Ftl*)a)->detach == Deferred;
}
static int
donescavenge(void *a)
{
return ((Ftl*)a)->needspace == 0;
}
static void
scavengeproc(void *arg)
{
Ftl *ftl;
int i;
Terase *e, *ne;
ftl = arg;
if(mustscavenge(ftl)){
if(ftl->detach == Deferred){
ftlfree(ftl);
fprint(2, "scavenge out of memory\n");
exits("1");
}
if(FTLDEBUG || ftl->trace || trace)
print("ftl: scavenge %ld\n", ftl->nfree);
e = bestcopy(ftl);
if(e == nil || ftl->xfer < 0 || (ne = ftl->unit[ftl->xfer]) == nil || ne->id != XferID || e == ne)
goto Fail;
if(copyunit(ftl, e, ne)){
i = ne->x; ne->x = e->x; e->x = i;
ftl->unit[ne->x] = ne;
ftl->unit[e->x] = e;
ftl->xfer = e->x;
e->id = XferID;
e->nbam = 0;
free(e->bam);
e->bam = nil;
e->bamx = 0;
e->nerase++;
eraseinit(ftl, e->offset, XferID, e->nerase);
}
Fail:
if(FTLDEBUG || ftl->trace || trace)
print("ftl: end scavenge %ld\n", ftl->nfree);
ftl->needspace = 0;
}
}
static int
scavenge(Ftl *ftl)
{
if(ftl->xfer < 0 || bestcopy(ftl) == nil)
return 0; /* you worm! */
if(!ftl->hasproc){
ftl->hasproc = 1;
}
ftl->needspace = 1;
scavengeproc(ftls);
return ftl->nfree;
}
static void
putbam(Ftl *ftl, Terase *e, int n, ulong entry)
{
uchar b[4];
e->bam[n] = entry;
PUT4(b, entry);
putflash(ftl, e->bamoffset + n*4, b, 4);
}
static ulong
allocblk(Ftl *ftl)
{
Terase *e;
int i, j;
i = ftl->lastx;
do{
e = ftl->unit[i];
if(e != nil && e->id != XferID && e->nfree){
ftl->lastx = i;
for(j=e->bamx; j<e->nbam; j++)
if(e->bam[j] == Bfree){
putbam(ftl, e, j, Bwriting);
ftl->nfree--;
e->nfree--;
e->bamx = j+1;
return (e->x<<16) | j;
}
e->nfree = 0;
print("ftl: unit %d:#%x nfree %ld but not free in BAM\n", e->x, e->id, e->nfree);
}
if(++i >= ftl->nunit)
i = 0;
}while(i != ftl->lastx);
return 0;
}
static int
mapblk(Ftl *ftl, ulong bno, Terase **ep, ulong *bp)
{
ulong v;
int x;
if(bno < ftl->nblock){
v = ftl->vbm[bno];
if(v == 0 || v == ~0)
return 0;
x = v>>16;
if(x >= ftl->nunit || x == ftl->xfer || ftl->unit[x] == nil){
print("ftl: corrupt format: bad block mapping %lud -> unit #%x\n", bno, x);
return 0;
}
*ep = ftl->unit[x];
*bp = v & 0xFFFF;
return 1;
}
return 0;
}
static void
eraseinit(Ftl *ftl, ulong offset, int id, int nerase)
{
union {
Merase m;
uchar block[ERASEHDRLEN];
} *m;
uchar *bam, *p;
int i, nov;
nov = ((ftl->segsize/Bsize)*4 + BAMoffset + Bsize - 1)/Bsize; /* number of overhead blocks (header, and BAM itself) */
if(nov*Bsize >= ftl->segsize) {
fprint(2, "ftl -- too small for files");
exits("1");
}
eraseflash(ftl, offset);
m = malloc(sizeof(*m));
if(m == nil) {
fprint(2, "nomem\n");
exits("1");
}
memset(m, 0xFF, sizeof(*m));
m->m.linktuple[0] = 0x13;
m->m.linktuple[1] = 0x3;
memmove(m->m.linktuple+2, "CIS", 3);
m->m.orgtuple[0] = 0x46;
m->m.orgtuple[1] = 0x57;
m->m.orgtuple[2] = 0x00;
memmove(m->m.orgtuple+3, "FTL100", 7);
m->m.nxfer = 1;
PUT4(m->m.nerase, nerase);
PUT2(m->m.id, id);
m->m.bshift = ftl->bshift;
m->m.eshift = ftl->eshift;
PUT2(m->m.pstart, 0);
PUT2(m->m.nunits, ftl->nunit);
PUT4(m->m.psize, ftl->size - nov*Bsize);
PUT4(m->m.vbmbase, 0xffffffff); /* we always calculate the VBM */
PUT2(m->m.nvbm, 0);
m->m.flags = 0;
m->m.code = 0xFF;
memmove(m->m.serial, "Inf1", 4);
PUT4(m->m.altoffset, 0);
PUT4(m->m.bamoffset, BAMoffset);
putflash(ftl, offset, m, ERASEHDRLEN);
free(m);
if(id == XferID)
return;
nov *= 4; /* now bytes of BAM */
bam = malloc(nov);
if(bam == nil) {
fprint(2, "nomem");
exits("1");
}
for(i=0; i<nov; i += 4){
p = bam+i;
PUT4(p, ControlBlock); /* reserve them */
}
putflash(ftl, offset+BAMoffset, bam, nov);
free(bam);
}
static Terase *
eraseload(Ftl *ftl, int x, ulong offset)
{
union {
Merase m;
uchar block[ERASEHDRLEN];
} *m;
Terase *e;
uchar *p;
int i, nbam;
ulong bno, v;
m = malloc(sizeof(*m));
if(m == nil) {
fprint(2, "nomem");
exits("1");
}
getflash(ftl, m, offset, ERASEHDRLEN);
if(memcmp(m->m.orgtuple+3, "FTL100", 7) != 0 ||
memcmp(m->m.serial, "Inf1", 4) != 0){
free(m);
return nil;
}
e = malloc(sizeof(*e));
if(e == nil){
free(m);
fprint(2, "nomem");
exits("1");
}
e->x = x;
e->id = GET2(m->m.id);
e->offset = offset;
e->bamoffset = GET4(m->m.bamoffset);
e->nerase = GET4(m->m.nerase);
e->bamx = 0;
e->nfree = 0;
e->nused = 0;
e->ndead = 0;
e->nbad = 0;
free(m);
if(e->bamoffset != BAMoffset){
free(e);
return nil;
}
e->bamoffset += offset;
if(e->id == XferID || e->id == XferBusy){
e->bam = nil;
e->nbam = 0;
return e;
}
nbam = ftl->segsize/Bsize;
e->bam = malloc(nbam*sizeof(*e->bam));
e->nbam = nbam;
getflash(ftl, e->bam, e->bamoffset, nbam*4);
/* scan BAM to build VBM */
e->bamx = 0;
for(i=0; i<nbam; i++){
p = (uchar*)&e->bam[i];
e->bam[i] = v = GET4(p);
if(v == Bwriting || v == Bdeleted)
e->ndead++;
else if(v == Bfree){
if(e->bamx == 0)
e->bamx = i;
e->nfree++;
ftl->nfree++;
}else{
switch(v & BlockType){
case ControlBlock:
break;
case DataBlock:
/* add to VBM */
if(v & (1<<31))
break; /* negative => VBM page, ignored */
bno = BNO(v & ~BlockType);
if(i < ftl->fstart || bno >= ftl->nblock){
print("ftl: unit %d:#%x bad bam[%d]=#%lux\n", e->x, e->id, i, v);
e->nbad++;
break;
}
ftl->vbm[bno] = (e->x<<16) | i;
e->nused++;
break;
case ReplacePage:
/* replacement VBM page; ignored */
break;
default:
print("ftl: unit %d:#%x bad bam[%d]=%lux\n", e->x, e->id, i, v);
case BadBlock:
e->nbad++;
break;
}
}
}
return e;
}
static void
erasefree(Terase *e)
{
free(e->bam);
free(e);
}
static void
eraseflash(Ftl *ftl, ulong offset)
{
offset += ftl->base;
if(FTLDEBUG || ftl->trace || trace)
print("ftl: erase seg @#%lux\n", offset);
memset(flashm+offset, 0xff, secsize);
}
static void
putflash(Ftl *ftl, ulong offset, void *buf, long n)
{
offset += ftl->base;
if(ftl->trace || trace)
print("ftl: write(#%lux, %ld)\n", offset, n);
memcpy(flashm+offset, buf, n);
}
static void
getflash(Ftl *ftl, void *buf, ulong offset, long n)
{
offset += ftl->base;
if(ftl->trace || trace)
print("ftl: read(#%lux, %ld)\n", offset, n);
memcpy(buf, flashm+offset, n);
}
#define BUFSIZE 8192
void
main(int argc, char **argv)
{
int k, r, sz, offset = 0;
char *buf, *buf1;
int fd1, fd2;
if (argc != 5) {
fprint(2, "usage: %s flashsize secsize kfsfile flashfile\n", argv[0]);
exits("1");
}
flashsize = strtol(argv[1], nil, 0);
secsize = strtol(argv[2], nil , 0);
fd1 = open(argv[3], OREAD);
fd2 = create(argv[4], OWRITE, 0644);
if (fd1 < 0 || fd2 < 0) {
fprint(2, "bad io files\n");
exits("1");
}
if(secsize == 0 || secsize > flashsize || secsize&(secsize-1) || 0&(secsize-1) || flashsize == 0 || flashsize != Nolimit && flashsize&(secsize-1)) {
fprint(2, "bad sizes\n");
exits("1");
}
for(k=0; k<32 && (1<<k) != secsize; k++)
;
flashm = malloc(flashsize);
buf = malloc(BUFSIZE);
if (flashm == nil) {
fprint(2, "no mem for flash\n");
exits("1");
}
ftls = mkftl("FLASH", 0, Nolimit, k, "format");
for (;;) {
r = read(fd1, buf, BUFSIZE);
if (r <= 0)
break;
if (ftlwrite(buf, r, offset) != r) {
fprint(2, "ftlwrite failed - input file too big\n");
exits("1");
}
offset += r;
}
write(fd2, flashm, flashsize);
close(fd1);
close(fd2);
ftlstat(offset);
/* ftls = mkftl("FLASH", 0, Nolimit, k, "init"); */
sz = offset;
offset = 0;
buf1 = malloc(BUFSIZE);
fd1 = open(argv[3], OREAD);
for (;;) {
r = read(fd1, buf1, BUFSIZE);
if (r <= 0)
break;
if (ftlread(buf, r, offset) != r) {
fprint(2, "ftlread failed\n");
exits("1");
}
if (memcmp(buf, buf1, r) != 0) {
fprint(2, "bad read\n");
exits("1");
}
offset += r;
}
close(fd1);
if (offset != sz) {
fprint(2, "bad final offset\n");
exits("1");
}
exits("0");
}