Blame | Last modification | View Log | RSS feed
/*
* File system devices.
* Follows device config in Ken's file server.
* Builds mirrors, concatenations, interleavings, and partitions
* of devices out of other (inner) devices.
* It is ok if inner devices are provided by this driver.
*
* Built files are grouped on different directories
* (called trees, and used to represent disks).
* The "#k/fs" tree is always available and never goes away.
* Configuration changes happen only while no I/O is in progress.
*
* Default sector size is one byte unless changed by the "disk" ctl.
*/
#include "u.h"
#include "../port/lib.h"
#include "mem.h"
#include "dat.h"
#include "fns.h"
#include "io.h"
#include "ureg.h"
#include "../port/error.h"
enum
{
Fnone,
Fmirror, /* mirror of others */
Fcat, /* catenation of others */
Finter, /* interleaving of others */
Fpart, /* part of other */
Fclear, /* start over */
Fdel, /* delete a configure device */
Fdisk, /* set default tree and sector sz*/
Sectorsz = 1,
Blksize = 8*1024, /* for Finter only */
Incr = 5, /* Increments for the dev array */
/*
* All qids are decorated with the tree number.
* #k/fs is tree number 0, is automatically added and
* its first qid is for the ctl file. It never goes away.
*/
Qtop = 0, /* #k */
Qdir, /* directory (#k/fs) */
Qctl, /* ctl, only for #k/fs/ctl */
Qfirst, /* first qid assigned for device */
Iswrite = 0,
Isread,
Optional = 0,
Mustexist,
/* tunable parameters */
Maxconf = 4*1024, /* max length for config */
Ndevs = 32, /* max. inner devs per command */
Ntrees = 128, /* max. number of trees */
Maxretries = 3, /* max. retries of i/o errors */
Retrypause = 5000, /* ms. to pause between retries */
};
typedef struct Inner Inner;
typedef struct Fsdev Fsdev;
typedef struct Tree Tree;
struct Inner
{
char *iname; /* inner device name */
vlong isize; /* size of inner device */
Chan *idev; /* inner device */
};
struct Fsdev
{
Ref; /* one per Chan doing I/O */
int gone; /* true if removed */
int vers; /* qid version for this device */
int type; /* Fnone, Fmirror, ... */
char *name; /* name for this fsdev */
Tree* tree; /* where the device is kept */
vlong size; /* min(inner[X].isize) */
vlong start; /* start address (for Fpart) */
uint ndevs; /* number of inner devices */
int perm; /* minimum of inner device perms */
Inner *inner[Ndevs]; /* inner devices */
};
struct Tree
{
char *name; /* name for #k/<name> */
Fsdev **devs; /* devices in dir. */
uint ndevs; /* number of devices */
uint nadevs; /* number of allocated devices in devs */
};
#define dprint if(debug)print
extern Dev fsdevtab; /* forward */
static RWlock lck; /* r: use devices; w: change config */
static Tree fstree; /* The main "fs" tree. Never goes away */
static Tree *trees[Ntrees]; /* internal representation of config */
static int ntrees; /* max number of trees */
static int qidvers;
static char *disk; /* default tree name used */
static char *source; /* default inner device used */
static int sectorsz = Sectorsz; /* default sector size */
static char confstr[Maxconf]; /* textual configuration */
static int debug;
static char cfgstr[] = "fsdev:\n";
static Qid tqid = {Qtop, 0, QTDIR};
static Qid cqid = {Qctl, 0, 0};
static char* tnames[] = {
[Fmirror] "mirror",
[Fcat] "cat",
[Finter] "inter",
[Fpart] "part",
};
static Cmdtab configs[] = {
Fmirror,"mirror", 0,
Fcat, "cat", 0,
Finter, "inter", 0,
Fpart, "part", 0,
Fclear, "clear", 1,
Fdel, "del", 2,
Fdisk, "disk", 0,
};
static char Egone[] = "device is gone"; /* file has been removed */
static char*
seprintdev(char *s, char *e, Fsdev *mp)
{
int i;
if(mp == nil)
return seprint(s, e, "<null Fsdev>");
if(mp->type < 0 || mp->type >= nelem(tnames) || tnames[mp->type] == nil)
return seprint(s, e, "bad device type %d\n", mp->type);
s = strecpy(s, e, tnames[mp->type]);
if(mp->tree != &fstree)
s = seprint(s, e, " %s/%s", mp->tree->name, mp->name);
else
s = seprint(s, e, " %s", mp->name);
for(i = 0; i < mp->ndevs; i++)
s = seprint(s, e, " %s", mp->inner[i]->iname);
switch(mp->type){
case Fmirror:
case Fcat:
case Finter:
s = strecpy(s, e, "\n");
break;
case Fpart:
s = seprint(s, e, " %ulld %ulld\n", mp->start, mp->size);
break;
default:
panic("#k: seprintdev bug");
}
return s;
}
static vlong
mkpath(int tree, int devno)
{
return (tree&0xFFFF)<<16 | devno&0xFFFF;
}
static int
path2treeno(int q)
{
return q>>16 & 0xFFFF;
}
static int
path2devno(int q)
{
return q & 0xFFFF;
}
static Tree*
gettree(int i, int mustexist)
{
dprint("gettree %d\n", i);
if(i < 0)
panic("#k: bug: bad tree index %d in gettree", i);
if(i >= ntrees || trees[i] == nil)
if(mustexist)
error(Enonexist);
else
return nil;
return trees[i];
}
static Fsdev*
getdev(Tree *t, int i, int mustexist)
{
dprint("getdev %d\n", i);
if(i < 0)
panic("#k: bug: bad dev index %d in getdev", i);
if(i >= t->nadevs || t->devs[i] == nil)
if(mustexist)
error(Enonexist);
else
return nil;
return t->devs[i];
}
static Fsdev*
path2dev(int q)
{
Tree *t;
dprint("path2dev %ux\n", q);
t = gettree(path2treeno(q), Mustexist);
return getdev(t, path2devno(q) - Qfirst, Mustexist);
}
static Tree*
treealloc(char *name)
{
int i;
Tree *t;
dprint("treealloc %s\n", name);
for(i = 0; i < nelem(trees); i++)
if(trees[i] == nil)
break;
if(i == nelem(trees))
return nil;
t = trees[i] = mallocz(sizeof(Tree), 1);
if(t == nil)
return nil;
if(i == ntrees)
ntrees++;
kstrdup(&t->name, name);
return t;
}
static Tree*
lookuptree(char *name)
{
int i;
dprint("lookuptree %s\n", name);
for(i = 0; i < ntrees; i++)
if(trees[i] != nil && strcmp(trees[i]->name, name) == 0)
return trees[i];
return nil;
}
static Fsdev*
devalloc(Tree *t, char *name)
{
int i, ndevs;
Fsdev *mp, **devs;
dprint("devalloc %s %s\n", t->name, name);
mp = mallocz(sizeof(Fsdev), 1);
if(mp == nil)
return nil;
for(i = 0; i < t->nadevs; i++)
if(t->devs[i] == nil)
break;
if(i >= t->nadevs){
if(t->nadevs % Incr == 0){
ndevs = t->nadevs + Incr;
devs = realloc(t->devs, ndevs * sizeof(Fsdev*));
if(devs == nil){
free(mp);
return nil;
}
t->devs = devs;
}
t->devs[t->nadevs] = nil;
t->nadevs++;
}
kstrdup(&mp->name, name);
mp->vers = ++qidvers;
mp->tree = t;
t->devs[i] = mp;
t->ndevs++;
return mp;
}
static void
deltree(Tree *t)
{
int i;
dprint("deltree %s\n", t->name);
for(i = 0; i < ntrees; i++)
if(trees[i] == t){
if(i > 0){ /* "fs" never goes away */
free(t->name);
free(t->devs);
free(t);
trees[i] = nil;
}
return;
}
panic("#k: deltree: bug: tree not found");
}
/*
* A device is gone and we know that all its users are gone.
* A tree is gone when all its devices are gone ("fs" is never gone).
* Must close devices outside locks, so we could nest our own devices.
*/
static void
mdeldev(Fsdev *mp)
{
int i;
Inner *in;
Tree *t;
dprint("deldev %s gone %d ref %uld\n", mp->name, mp->gone, mp->ref);
mp->gone = 1;
mp->vers = ++qidvers;
wlock(&lck);
t = mp->tree;
for(i = 0; i < t->nadevs; i++)
if(t->devs[i] == mp){
t->devs[i] = nil;
t->ndevs--;
if(t->ndevs == 0)
deltree(t);
break;
}
wunlock(&lck);
free(mp->name);
for(i = 0; i < mp->ndevs; i++){
in = mp->inner[i];
if(in->idev != nil)
cclose(in->idev);
free(in->iname);
free(in);
}
if(debug)
memset(mp, 9, sizeof *mp); /* poison */
free(mp);
}
/*
* Delete one or all devices in one or all trees.
*/
static void
mdelctl(char *tname, char *dname)
{
int i, alldevs, alltrees, some;
Fsdev *mp;
Tree *t;
dprint("delctl %s\n", dname);
alldevs = strcmp(dname, "*") == 0;
alltrees = strcmp(tname, "*") == 0;
some = 0;
Again:
wlock(&lck);
for(i = 0; i < ntrees; i++){
t = trees[i];
if(t == nil)
continue;
if(alltrees == 0 && strcmp(t->name, tname) != 0)
continue;
for(i = 0; i < t->nadevs; i++){
mp = t->devs[i];
if(t->devs[i] == nil)
continue;
if(alldevs == 0 && strcmp(mp->name, dname) != 0)
continue;
/*
* Careful: must close outside locks and that
* may change the file tree we are looking at.
*/
some++;
mp->gone = 1;
if(mp->ref == 0){
incref(mp); /* keep it there */
wunlock(&lck);
mdeldev(mp);
goto Again; /* tree can change */
}
}
}
wunlock(&lck);
if(some == 0 && alltrees == 0)
error(Enonexist);
}
static void
setdsize(Fsdev* mp, vlong *ilen)
{
int i;
vlong inlen;
Inner *in;
dprint("setdsize %s\n", mp->name);
for (i = 0; i < mp->ndevs; i++){
in = mp->inner[i];
in->isize = ilen[i];
inlen = in->isize;
switch(mp->type){
case Finter:
/* truncate to multiple of Blksize */
inlen &= ~(Blksize-1);
in->isize = inlen;
/* fall through */
case Fmirror:
/* use size of smallest inner device */
if (mp->size == 0 || mp->size > inlen)
mp->size = inlen;
break;
case Fcat:
mp->size += inlen;
break;
case Fpart:
if(mp->start > inlen)
error("partition starts after device end");
if(inlen < mp->start + mp->size){
print("#k: %s: partition truncated from "
"%lld to %lld bytes\n", mp->name,
mp->size, inlen - mp->start);
mp->size = inlen - mp->start;
}
break;
}
}
if(mp->type == Finter)
mp->size *= mp->ndevs;
}
static void
validdevname(Tree *t, char *dname)
{
int i;
for(i = 0; i < t->nadevs; i++)
if(t->devs[i] != nil && strcmp(t->devs[i]->name, dname) == 0)
error(Eexist);
}
static void
parseconfig(char *a, long n, Cmdbuf **cbp, Cmdtab **ctp)
{
Cmdbuf *cb;
Cmdtab *ct;
*cbp = cb = parsecmd(a, n);
*ctp = ct = lookupcmd(cb, configs, nelem(configs));
cb->f++; /* skip command */
cb->nf--;
switch(ct->index){
case Fmirror:
case Fcat:
case Finter:
if(cb->nf < 2)
error("too few arguments for ctl");
if(cb->nf - 1 > Ndevs)
error("too many devices in ctl");
break;
case Fdisk:
if(cb->nf < 1 || cb->nf > 3)
error("ctl usage: disk name [sz dev]");
break;
case Fpart:
if(cb->nf != 4 && (cb->nf != 3 || source == nil))
error("ctl usage: part new [file] off len");
break;
}
}
static void
parsename(char *name, char *disk, char **tree, char **dev)
{
char *slash;
slash = strchr(name, '/');
if(slash == nil){
if(disk != nil)
*tree = disk;
else
*tree = "fs";
*dev = name;
}else{
*tree = name;
*slash++ = 0;
*dev = slash;
}
validname(*tree, 0);
validname(*dev, 0);
}
static int
getattrs(Chan *c, vlong *lenp, int *permp)
{
uchar buf[128]; /* old DIRLEN plus a little should be plenty */
Dir d;
long l;
*lenp = 0;
*permp = 0;
l = devtab[c->type]->stat(c, buf, sizeof buf);
if (l >= 0 && convM2D(buf, l, &d, nil) > 0) {
*lenp = d.length;
*permp = d.mode & 0777;
}
return l;
}
/*
* Process a single line of configuration,
* often of the form "cmd newname idev0 idev1".
* locking is tricky, because we need a write lock to
* add/remove devices yet adding/removing them may lead
* to calls to this driver that require a read lock (when
* inner devices are also provided by us).
*/
static void
mconfig(char* a, long n)
{
int i;
int *iperm;
vlong size, start;
vlong *ilen;
char *tname, *dname, *fakef[4];
Chan **idev;
Cmdbuf *cb;
Cmdtab *ct;
Fsdev *mp;
Inner *inprv;
Tree *t;
/* ignore comments & empty lines */
if (*a == '\0' || *a == '#' || *a == '\n')
return;
dprint("mconfig\n");
size = 0;
start = 0;
mp = nil;
cb = nil;
idev = nil;
ilen = nil;
iperm = nil;
if(waserror()){
free(cb);
nexterror();
}
parseconfig(a, n, &cb, &ct);
switch (ct->index) {
case Fdisk:
kstrdup(&disk, cb->f[0]);
if(cb->nf >= 2)
sectorsz = strtoul(cb->f[1], 0, 0);
else
sectorsz = Sectorsz;
if(cb->nf == 3)
kstrdup(&source, cb->f[2]);
else{
free(source);
source = nil;
}
poperror();
free(cb);
return;
case Fclear:
poperror();
free(cb);
mdelctl("*", "*"); /* del everything */
return;
case Fpart:
if(cb->nf == 3){
/*
* got a request in the format of sd(3),
* pretend we got one in our format.
* later we change end to be len.
*/
fakef[0] = cb->f[0];
fakef[1] = source;
fakef[2] = cb->f[1];
fakef[3] = cb->f[2];
cb->f = fakef;
cb->nf = 4;
}
start = strtoll(cb->f[2], nil, 10);
size = strtoll(cb->f[3], nil, 10);
if(cb->f == fakef)
size -= start; /* it was end */
cb->nf -= 2;
break;
}
parsename(cb->f[0], disk, &tname, &dname);
for(i = 1; i < cb->nf; i++)
validname(cb->f[i], 1);
if(ct->index == Fdel){
mdelctl(tname, dname);
poperror();
free(cb);
return;
}
/*
* Open all inner devices while we have only a read lock.
*/
poperror();
rlock(&lck);
if(waserror()){
runlock(&lck);
Fail:
for(i = 1; i < cb->nf; i++)
if(idev != nil && idev[i-1] != nil)
cclose(idev[i]);
if(mp != nil)
mdeldev(mp);
free(idev);
free(ilen);
free(iperm);
free(cb);
nexterror();
}
/* record names, lengths and perms of all named files */
idev = smalloc(sizeof(Chan*) * Ndevs);
ilen = smalloc(sizeof(vlong) * Ndevs);
iperm = smalloc(sizeof(int) * Ndevs);
for(i = 1; i < cb->nf; i++){
idev[i-1] = namec(cb->f[i], Aopen, ORDWR, 0);
getattrs(idev[i-1], &ilen[i-1], &iperm[i-1]);
}
poperror();
runlock(&lck);
/*
* Get a write lock and add the device if we can.
*/
wlock(&lck);
if(waserror()){
wunlock(&lck);
goto Fail;
}
t = lookuptree(tname);
if(t != nil)
validdevname(t, dname);
else
t = treealloc(tname);
if(t == nil)
error("no more trees");
mp = devalloc(t, dname);
if(mp == nil){
if(t->ndevs == 0) /* it was created for us */
deltree(t); /* but we will not mdeldev() */
error(Enomem);
}
/* construct mp from iname, idev and iperm arrays */
mp->type = ct->index;
if(mp->type == Fpart){
mp->start = start * sectorsz;
mp->size = size * sectorsz;
}
mp->perm = 0666;
for(i = 1; i < cb->nf; i++){
inprv = mp->inner[i-1] = mallocz(sizeof(Inner), 1);
if(inprv == nil)
error(Enomem);
mp->ndevs++;
kstrdup(&inprv->iname, cb->f[i]);
inprv->idev = idev[i-1];
idev[i-1] = nil;
/* use the most restrictive of the inner permissions */
mp->perm &= iperm[i-1];
}
setdsize(mp, ilen);
poperror();
wunlock(&lck);
free(idev);
free(ilen);
free(iperm);
free(cb);
}
static void
rdconf(void)
{
int mustrd;
char *c, *e, *p, *s;
Chan *cc;
static int configed;
/* only read config file once */
if (configed)
return;
configed = 1;
dprint("rdconf\n");
/* add the std "fs" tree */
trees[0] = &fstree;
ntrees++;
fstree.name = "fs";
/* identify the config file */
s = getconf("fsconfig");
if (s == nil){
mustrd = 0;
s = "/dev/sdC0/fscfg";
} else
mustrd = 1;
/* read it */
cc = nil;
c = nil;
if (waserror()){
if (cc != nil)
cclose(cc);
if (c)
free(c);
if (!mustrd)
return;
nexterror();
}
cc = namec(s, Aopen, OREAD, 0);
devtab[cc->type]->read(cc, confstr, sizeof confstr, 0);
cclose(cc);
cc = nil;
/* validate, copy and erase config; mconfig will repopulate confstr */
if (strncmp(confstr, cfgstr, sizeof cfgstr - 1) != 0)
error("bad #k config, first line must be: 'fsdev:\\n'");
kstrdup(&c, confstr + sizeof cfgstr - 1);
memset(confstr, 0, sizeof confstr);
/* process config copy one line at a time */
for (p = c; p != nil && *p != '\0'; p = e){
e = strchr(p, '\n');
if (e == nil)
e = p + strlen(p);
else
e++;
mconfig(p, e - p);
}
USED(cc); /* until now, can be used in waserror clause */
poperror();
}
static int
mgen(Chan *c, char*, Dirtab*, int, int i, Dir *dp)
{
int treeno;
Fsdev *mp;
Qid qid;
Tree *t;
dprint("mgen %#ullx %d\n", c->qid.path, i);
qid.type = QTDIR;
qid.vers = 0;
if(c->qid.path == Qtop){
if(i == DEVDOTDOT){
devdir(c, tqid, "#k", 0, eve, DMDIR|0775, dp);
return 1;
}
t = gettree(i, Optional);
if(t == nil){
dprint("no\n");
return -1;
}
qid.path = mkpath(i, Qdir);
devdir(c, qid, t->name, 0, eve, DMDIR|0775, dp);
return 1;
}
treeno = path2treeno(c->qid.path);
t = gettree(treeno, Optional);
if(t == nil){
dprint("no\n");
return -1;
}
if((c->qid.type & QTDIR) != 0){
if(i == DEVDOTDOT){
devdir(c, tqid, "#k", 0, eve, DMDIR|0775, dp);
return 1;
}
if(treeno == 0){
/* take care of #k/fs/ctl */
if(i == 0){
devdir(c, cqid, "ctl", 0, eve, 0664, dp);
return 1;
}
i--;
}
mp = getdev(t, i, Optional);
if(mp == nil){
dprint("no\n");
return -1;
}
qid.type = QTFILE;
qid.vers = mp->vers;
qid.path = mkpath(treeno, Qfirst+i);
devdir(c, qid, mp->name, mp->size, eve, mp->perm, dp);
return 1;
}
if(i == DEVDOTDOT){
qid.path = mkpath(treeno, Qdir);
devdir(c, qid, t->name, 0, eve, DMDIR|0775, dp);
return 1;
}
dprint("no\n");
return -1;
}
static Chan*
mattach(char *spec)
{
dprint("mattach\n");
return devattach(fsdevtab.dc, spec);
}
static Walkqid*
mwalk(Chan *c, Chan *nc, char **name, int nname)
{
Walkqid *wq;
rdconf();
dprint("mwalk %llux\n", c->qid.path);
rlock(&lck);
if(waserror()){
runlock(&lck);
nexterror();
}
wq = devwalk(c, nc, name, nname, 0, 0, mgen);
poperror();
runlock(&lck);
return wq;
}
static int
mstat(Chan *c, uchar *db, int n)
{
int p;
Dir d;
Fsdev *mp;
Qid q;
Tree *t;
dprint("mstat %llux\n", c->qid.path);
rlock(&lck);
if(waserror()){
runlock(&lck);
nexterror();
}
p = c->qid.path;
memset(&d, 0, sizeof d);
switch(p){
case Qtop:
devdir(c, tqid, "#k", 0, eve, DMDIR|0775, &d);
break;
case Qctl:
devdir(c, cqid, "ctl", 0, eve, 0664, &d);
break;
default:
t = gettree(path2treeno(p), Mustexist);
if(c->qid.type & QTDIR)
devdir(c, c->qid, t->name, 0, eve, DMDIR|0775, &d);
else{
mp = getdev(t, path2devno(p) - Qfirst, Mustexist);
q = c->qid;
q.vers = mp->vers;
devdir(c, q, mp->name, mp->size, eve, mp->perm, &d);
}
}
n = convD2M(&d, db, n);
if (n == 0)
error(Ebadarg);
poperror();
runlock(&lck);
return n;
}
static Chan*
mopen(Chan *c, int omode)
{
int q;
Fsdev *mp;
dprint("mopen %llux\n", c->qid.path);
if((c->qid.type & QTDIR) && omode != OREAD)
error(Eperm);
if(c->qid.path != Qctl && (c->qid.type&QTDIR) == 0){
rlock(&lck);
if(waserror()){
runlock(&lck);
nexterror();
}
q = c->qid.path;
mp = path2dev(q);
if(mp->gone)
error(Egone);
devpermcheck(eve, mp->perm, omode);
incref(mp);
poperror();
runlock(&lck);
}
/*
* Our mgen does not return the info for the qid
* but only for its children. Don't use devopen here.
*/
c->offset = 0;
c->mode = openmode(omode & ~OTRUNC);
c->flag |= COPEN;
return c;
}
static void
mclose(Chan *c)
{
int mustdel, q;
Fsdev *mp;
dprint("mclose %llux\n", c->qid.path);
if(c->qid.type & QTDIR || !(c->flag & COPEN))
return;
rlock(&lck);
if(waserror()){
runlock(&lck);
nexterror();
}
mustdel = 0;
mp = nil;
q = c->qid.path;
if(q == Qctl){
free(disk);
disk = nil; /* restore defaults */
free(source);
source = nil;
sectorsz = Sectorsz;
}else{
mp = path2dev(q);
if(mp->gone != 0 && mp->ref == 1)
mustdel = 1;
else
decref(mp);
}
poperror();
runlock(&lck);
if(mustdel)
mdeldev(mp);
}
static long
io(Fsdev *mp, Inner *in, int isread, void *a, long l, vlong off)
{
long wl;
Chan *mc;
mc = in->idev;
if(mc == nil)
error(Egone);
if (waserror()) {
print("#k: %s: byte %,lld count %ld (of #k/%s): %s error: %s\n",
in->iname, off, l, mp->name, (isread? "read": "write"),
(up && up->errstr? up->errstr: ""));
nexterror();
}
if (isread)
wl = devtab[mc->type]->read(mc, a, l, off);
else
wl = devtab[mc->type]->write(mc, a, l, off);
poperror();
return wl;
}
/* NB: a transfer could span multiple inner devices */
static long
catio(Fsdev *mp, int isread, void *a, long n, vlong off)
{
int i;
long l, res;
Inner *in;
if(debug)
print("catio %d %p %ld %lld\n", isread, a, n, off);
res = n;
for (i = 0; n > 0 && i < mp->ndevs; i++){
in = mp->inner[i];
if (off >= in->isize){
off -= in->isize;
continue; /* not there yet */
}
if (off + n > in->isize)
l = in->isize - off;
else
l = n;
if(debug)
print("\tdev %d %p %ld %lld\n", i, a, l, off);
if (io(mp, in, isread, a, l, off) != l)
error(Eio);
a = (char*)a + l;
off = 0;
n -= l;
}
if(debug)
print("\tres %ld\n", res - n);
return res - n;
}
static long
interio(Fsdev *mp, int isread, void *a, long n, vlong off)
{
int i;
long boff, res, l, wl, wsz;
vlong woff, blk, mblk;
blk = off / Blksize;
boff = off % Blksize;
wsz = Blksize - boff;
res = n;
while(n > 0){
mblk = blk / mp->ndevs;
i = blk % mp->ndevs;
woff = mblk*Blksize + boff;
if (n > wsz)
l = wsz;
else
l = n;
wl = io(mp, mp->inner[i], isread, a, l, woff);
if (wl != l)
error(Eio);
blk++;
boff = 0;
wsz = Blksize;
a = (char*)a + l;
n -= l;
}
return res;
}
static char*
seprintconf(char *s, char *e)
{
int i, j;
Tree *t;
*s = 0;
for(i = 0; i < ntrees; i++){
t = trees[i];
if(t != nil)
for(j = 0; j < t->nadevs; j++)
if(t->devs[j] != nil)
s = seprintdev(s, e, t->devs[j]);
}
return s;
}
static long
mread(Chan *c, void *a, long n, vlong off)
{
int i, retry;
long l, res;
Fsdev *mp;
Tree *t;
dprint("mread %llux\n", c->qid.path);
rlock(&lck);
if(waserror()){
runlock(&lck);
nexterror();
}
res = -1;
if(c->qid.type & QTDIR){
res = devdirread(c, a, n, 0, 0, mgen);
goto Done;
}
if(c->qid.path == Qctl){
seprintconf(confstr, confstr + sizeof(confstr));
res = readstr((long)off, a, n, confstr);
goto Done;
}
t = gettree(path2treeno(c->qid.path), Mustexist);
mp = getdev(t, path2devno(c->qid.path) - Qfirst, Mustexist);
if(off >= mp->size){
res = 0;
goto Done;
}
if(off + n > mp->size)
n = mp->size - off;
if(n == 0){
res = 0;
goto Done;
}
switch(mp->type){
case Fcat:
res = catio(mp, Isread, a, n, off);
break;
case Finter:
res = interio(mp, Isread, a, n, off);
break;
case Fpart:
res = io(mp, mp->inner[0], Isread, a, n, mp->start + off);
break;
case Fmirror:
retry = 0;
do {
if (retry > 0) {
print("#k/%s: retry %d read for byte %,lld "
"count %ld: %s\n", mp->name, retry, off,
n, (up && up->errstr? up->errstr: ""));
/*
* pause before retrying in case it's due to
* a transient bus or controller problem.
*/
tsleep(&up->sleep, return0, 0, Retrypause);
}
for (i = 0; i < mp->ndevs; i++){
if (waserror())
continue;
l = io(mp, mp->inner[i], Isread, a, n, off);
poperror();
if (l >= 0){
res = l;
break; /* read a good copy */
}
}
} while (i == mp->ndevs && ++retry <= Maxretries);
if (retry > Maxretries) {
/* no mirror had a good copy of the block */
print("#k/%s: byte %,lld count %ld: CAN'T READ "
"from mirror: %s\n", mp->name, off, n,
(up && up->errstr? up->errstr: ""));
error(Eio);
} else if (retry > 0)
print("#k/%s: byte %,lld count %ld: retry read OK "
"from mirror: %s\n", mp->name, off, n,
(up && up->errstr? up->errstr: ""));
break;
}
Done:
poperror();
runlock(&lck);
return res;
}
static long
mwrite(Chan *c, void *a, long n, vlong off)
{
int i, allbad, anybad, retry;
long l, res;
Fsdev *mp;
Tree *t;
dprint("mwrite %llux\n", c->qid.path);
if (c->qid.type & QTDIR)
error(Eisdir);
if (c->qid.path == Qctl){
mconfig(a, n);
return n;
}
rlock(&lck);
if(waserror()){
runlock(&lck);
nexterror();
}
t = gettree(path2treeno(c->qid.path), Mustexist);
mp = getdev(t, path2devno(c->qid.path) - Qfirst, Mustexist);
if(off >= mp->size){
res = 0;
goto Done;
}
if(off + n > mp->size)
n = mp->size - off;
if(n == 0){
res = 0;
goto Done;
}
res = n;
switch(mp->type){
case Fcat:
res = catio(mp, Iswrite, a, n, off);
break;
case Finter:
res = interio(mp, Iswrite, a, n, off);
break;
case Fpart:
res = io(mp, mp->inner[0], Iswrite, a, n, mp->start + off);
if (res != n)
error(Eio);
break;
case Fmirror:
retry = 0;
do {
if (retry > 0) {
print("#k/%s: retry %d write for byte %,lld "
"count %ld: %s\n", mp->name, retry, off,
n, (up && up->errstr? up->errstr: ""));
/*
* pause before retrying in case it's due to
* a transient bus or controller problem.
*/
tsleep(&up->sleep, return0, 0, Retrypause);
}
allbad = 1;
anybad = 0;
for (i = mp->ndevs - 1; i >= 0; i--){
if (waserror()) {
anybad = 1;
continue;
}
l = io(mp, mp->inner[i], Iswrite, a, n, off);
poperror();
if (l == n)
allbad = 0; /* wrote a good copy */
else
anybad = 1;
}
} while (anybad && ++retry <= Maxretries);
if (allbad) {
/* no mirror took a good copy of the block */
print("#k/%s: byte %,lld count %ld: CAN'T WRITE "
"to mirror: %s\n", mp->name, off, n,
(up && up->errstr? up->errstr: ""));
error(Eio);
} else if (retry > 0)
print("#k/%s: byte %,lld count %ld: retry wrote OK "
"to mirror: %s\n", mp->name, off, n,
(up && up->errstr? up->errstr: ""));
break;
}
Done:
poperror();
runlock(&lck);
return res;
}
Dev fsdevtab = {
'k',
"fs",
devreset,
devinit,
devshutdown,
mattach,
mwalk,
mstat,
mopen,
devcreate,
mclose,
mread,
devbread,
mwrite,
devbwrite,
devremove,
devwstat,
devpower,
devconfig,
};