upas/fs: getting rid of the fine-grain locking...

now that locking works, its time to get rid of it.
given that the only concurrency is between the periodic reader
process and the filesystem code, just make sure the filesystem
rpc handlers do not run concurrenty while syncing is in progress
with a single qlock.
This commit is contained in:
cinap_lenrek 2017-03-15 19:30:33 +01:00
parent c8d9390070
commit efddf48500
3 changed files with 22 additions and 127 deletions

View file

@ -147,7 +147,6 @@ struct Mcache {
typedef struct Mailbox Mailbox;
struct Mailbox {
QLock;
int refs;
Mailbox *next;
int id;
@ -355,7 +354,6 @@ extern ulong msgallocd;
extern ulong msgfreed;
extern Mailbox *mbl;
extern Message *root;
extern QLock mbllock;
extern Refs *rtab;
#define dprint(...) if(debug) fprint(2, __VA_ARGS__); else {}

View file

@ -109,7 +109,6 @@ enum
Hsize= 1999,
};
char *mntpt;
char user[Elemlen];
int Dflag;
@ -121,7 +120,6 @@ int debug;
int plumbing = 1;
ulong cachetarg = Maxcache;
Mailbox *mbl;
QLock mbllock;
static int messagesize = 8*1024 + IOHDRSZ;
static int mfd[2];
@ -133,6 +131,7 @@ static Hash *htab[Hsize];
static Fcall rhdr;
static Fcall thdr;
static Fid *fids;
static QLock synclock;
void
sanemsg(Message *m)
@ -778,17 +777,13 @@ doclone(Fid *f, int nfid)
nf->busy = 1;
nf->open = 0;
nf->mb = f->mb;
if(nf->mb){
qlock(nf->mb);
if(nf->mb)
mboxincref(nf->mb);
}
if(nf->m = f->m)
msgincref(gettopmsg(nf->mb, nf->m));
if(nf->mtop = f->mtop)
msgincref(nf->mtop);
nf->qid = f->qid;
if(nf->mb)
qunlock(nf->mb);
return nf;
}
@ -816,10 +811,6 @@ dowalk(Fid *f, char *name)
t = FILE(f->qid.path);
rv = Enotexist;
qlock(&mbllock);
if(f->mb)
qlock(f->mb);
/* this must catch everything except . and .. */
retry:
t1 = FILE(f->qid.path);
@ -833,12 +824,8 @@ retry:
if(h != nil){
if(f->m)
msgdecref(f->mb, gettopmsg(f->mb, f->m));
if(f->mb && f->mb != h->mb){
qunlock(f->mb);
if(f->mb && f->mb != h->mb)
mboxdecref(f->mb);
}
if(h->mb && h->mb != f->mb)
qlock(h->mb);
f->mb = h->mb;
f->m = h->m;
if(f->m)
@ -864,10 +851,6 @@ retry:
goto retry;
}
if(f->mb)
qunlock(f->mb);
qunlock(&mbllock);
if(rv == nil)
return rv;
@ -890,12 +873,9 @@ retry:
f->qid.vers = 0;
mb = f->mb;
f->mb = nil;
qlock(&mbllock);
mboxdecref(mb);
qunlock(&mbllock);
break;
case Qdir:
qlock(f->mb);
if(Topmsg(f->mb, f->m)){
f->qid.path = PATH(f->mb->id, Qmbox);
f->qid.type = QTDIR;
@ -909,7 +889,6 @@ retry:
f->qid.path = PATH(f->m->id, Qdir);
f->qid.type = QTDIR;
}
qunlock(f->mb);
break;
}
rv = nil;
@ -975,12 +954,10 @@ ropen(Fid *f)
/* make sure we've decoded */
if(file == Qbody){
qlock(f->mb);
cachebody(f->mb, f->m);
decode(f->m);
convert(f->m);
putcache(f->mb, f->m);
qunlock(f->mb);
}
rhdr.iounit = 0;
@ -1003,24 +980,20 @@ readtopdir(Fid*, uchar *buf, long off, int cnt, int blen)
long pos;
Mailbox *mb;
qlock(&mbllock);
n = 0;
pos = 0;
mkstat(&d, nil, nil, Qctl);
m = convD2M(&d, &buf[n], blen);
if(off <= pos){
if(m <= BIT16SZ || m > cnt)
goto out;
return n;
n += m;
cnt -= m;
}
pos += m;
for(mb = mbl; mb != nil; mb = mb->next){
qlock(mb);
mkstat(&d, mb, nil, Qmbox);
qunlock(mb);
m = convD2M(&d, &buf[n], blen - n);
if(off <= pos){
if(m <= BIT16SZ || m > cnt)
@ -1030,8 +1003,6 @@ readtopdir(Fid*, uchar *buf, long off, int cnt, int blen)
}
pos += m;
}
out:
qlock(&mbllock);
return n;
}
@ -1043,7 +1014,6 @@ readmboxdir(Fid *f, uchar *buf, long off, int cnt, int blen)
long pos;
Message *msg;
qlock(f->mb);
if(off == 0)
syncmbox(f->mb, 1);
@ -1054,7 +1024,7 @@ readmboxdir(Fid *f, uchar *buf, long off, int cnt, int blen)
if(off == 0){
if(m <= BIT16SZ || m > cnt){
f->fptr = nil;
goto out;
return n;
}
n += m;
cnt -= m;
@ -1091,8 +1061,6 @@ readmboxdir(Fid *f, uchar *buf, long off, int cnt, int blen)
f->foff = pos;
f->fptr = msg;
f->fvers = f->mb->vers;
out:
qunlock(f->mb);
return n;
}
@ -1104,7 +1072,6 @@ readmsgdir(Fid *f, uchar *buf, long off, int cnt, int blen)
long pos;
Message *msg;
qlock(f->mb);
n = 0;
pos = 0;
for(i = 0; i < Qmax; i++){
@ -1112,7 +1079,7 @@ readmsgdir(Fid *f, uchar *buf, long off, int cnt, int blen)
m = convD2M(&d, &buf[n], blen - n);
if(off <= pos){
if(m <= BIT16SZ || m > cnt)
goto out;
return n;
n += m;
cnt -= m;
}
@ -1129,8 +1096,6 @@ readmsgdir(Fid *f, uchar *buf, long off, int cnt, int blen)
}
pos += m;
}
out:
qunlock(f->mb);
return n;
}
@ -1171,7 +1136,6 @@ rread(Fid *f)
return nil;
}
qlock(f->mb);
switch(t){
case Qctl:
rhdr.count = 0;
@ -1214,7 +1178,6 @@ rread(Fid *f)
}
break;
}
qunlock(f->mb);
return nil;
}
@ -1335,10 +1298,7 @@ rwrite(Fid *f)
argc = tokenize(thdr.data, argv, nelem(argvbuf));
if(argc == 0)
return Ebadctl;
qlock(f->mb);
err = f->mb->ctl(f->mb, argc, argv);
qunlock(f->mb);
return err;
return f->mb->ctl(f->mb, argc, argv);
}
break;
case Qflags:
@ -1347,11 +1307,8 @@ rwrite(Fid *f)
*/
if(!f->mb || !f->m)
break;
qlock(f->mb);
m = gettopmsg(f->mb, f->m);
err = modflags(f->mb, m, thdr.data);
qunlock(f->mb);
return err;
return modflags(f->mb, m, thdr.data);
}
return Eperm;
}
@ -1366,8 +1323,6 @@ rclunk(Fid *f)
f->fid = -1;
f->open = 0;
mb = f->mb;
if(mb)
qlock(mb);
if(f->mtop)
msgdecref(mb, f->mtop);
if(f->m)
@ -1375,10 +1330,7 @@ rclunk(Fid *f)
f->m = f->mtop = nil;
if(mb){
f->mb = nil;
qunlock(mb);
qlock(&mbllock);
mboxdecref(mb);
qunlock(&mbllock);
}
f->busy = 0;
return 0;
@ -1388,11 +1340,9 @@ char *
rremove(Fid *f)
{
if(f->m != nil){
qlock(f->mb);
if(!f->m->deleted)
mailplumb(f->mb, f->m, 1);
f->m->deleted = Deleted;
qunlock(f->mb);
}
return rclunk(f);
}
@ -1402,15 +1352,11 @@ rstat(Fid *f)
{
Dir d;
if(f->mb)
qlock(f->mb);
if(FILE(f->qid.path) == Qmbox)
syncmbox(f->mb, 1);
mkstat(&d, f->mb, f->m, FILE(f->qid.path));
rhdr.nstat = convD2M(&d, mbuf, messagesize - IOHDRSZ);
rhdr.stat = mbuf;
if(f->mb)
qunlock(f->mb);
return 0;
}
@ -1473,6 +1419,7 @@ io(void)
if(Dflag)
fprint(2, "%s:<-%F\n", argv0, &thdr);
qlock(&synclock);
rhdr.data = (char*)mdata + messagesize;
if(!fcalls[thdr.type])
err = "bad fcall type";
@ -1486,6 +1433,8 @@ io(void)
rhdr.fid = thdr.fid;
}
rhdr.tag = thdr.tag;
qunlock(&synclock);
if(Dflag)
fprint(2, "%s:->%F\n", argv0, &rhdr);
n = convS2M(&rhdr, mdata, messagesize);
@ -1506,11 +1455,9 @@ reader(void)
setname(readerargv);
sleep(15*1000);
for(;;){
qlock(&synclock);
t = time(0);
qlock(&mbllock);
for(mb = mbl; mb != nil; mb = mb->next){
if(!canqlock(mb))
continue;
if(mb->waketime != 0 && t >= mb->waketime){
mb->waketime = 0;
break;
@ -1526,16 +1473,16 @@ reader(void)
free(d);
}
}
qunlock(mb);
}
qunlock(&mbllock);
if(mb != nil) {
syncmbox(mb, 1);
qunlock(mb);
} else
qunlock(&synclock);
} else {
qunlock(&synclock);
sleep(15*1000);
}
}
}
int
newid(void)
@ -1662,8 +1609,6 @@ readheader(Message *m, char *buf, int off, int cnt)
return to - buf;
}
QLock hashlock;
uint
hash(ulong ppath, char *name)
{
@ -1684,14 +1629,10 @@ hlook(ulong ppath, char *name)
int h;
Hash *hp;
qlock(&hashlock);
h = hash(ppath, name);
for(hp = htab[h]; hp != nil; hp = hp->next)
if(ppath == hp->ppath && strcmp(name, hp->name) == 0){
qunlock(&hashlock);
if(ppath == hp->ppath && strcmp(name, hp->name) == 0)
return hp;
}
qunlock(&hashlock);
return nil;
}
@ -1701,7 +1642,6 @@ henter(ulong ppath, char *name, Qid qid, Message *m, Mailbox *mb)
int h;
Hash *hp, **l;
qlock(&hashlock);
h = hash(ppath, name);
for(l = &htab[h]; *l != nil; l = &(*l)->next){
hp = *l;
@ -1709,18 +1649,15 @@ henter(ulong ppath, char *name, Qid qid, Message *m, Mailbox *mb)
hp->m = m;
hp->mb = mb;
hp->qid = qid;
qunlock(&hashlock);
return;
}
}
*l = hp = emalloc(sizeof(*hp));
hp->m = m;
hp->mb = mb;
hp->qid = qid;
hp->name = name;
hp->ppath = ppath;
qunlock(&hashlock);
}
void
@ -1729,7 +1666,6 @@ hfree(ulong ppath, char *name)
int h;
Hash *hp, **l;
qlock(&hashlock);
h = hash(ppath, name);
for(l = &htab[h]; *l != nil; l = &(*l)->next){
hp = *l;
@ -1740,7 +1676,6 @@ hfree(ulong ppath, char *name)
break;
}
}
qunlock(&hashlock);
}
void

View file

@ -65,7 +65,6 @@ syncmbox(Mailbox *mb, int doplumb)
int n, d, y, a;
Message *m, *next;
assert(!canqlock(mb));
a = mb->root->subname;
if(rdidxfile(mb, doplumb) == -2)
wridxfile(mb);
@ -146,9 +145,6 @@ mboxrename(char *a, char *b, int flags)
henter(PATH(0, Qtop), mb->name,
(Qid){PATH(mb->id, Qmbox), mb->vers, QTDIR}, nil, mb);
done:
if(mb == nil)
return err;
qunlock(mb);
return err;
}
@ -206,7 +202,6 @@ newmbox(char *path, char *name, int flags, Mailbox **r)
}
/* make sure name isn't taken */
qlock(&mbllock);
for(l = &mbl; *l != nil; l = &(*l)->next)
if(strcmp((*l)->name, mb->name) == 0){
if(strcmp(path, (*l)->path) == 0)
@ -216,7 +211,6 @@ newmbox(char *path, char *name, int flags, Mailbox **r)
if(mb->close)
mb->close(mb);
free(mb);
qunlock(&mbllock);
return rv;
}
@ -229,9 +223,7 @@ newmbox(char *path, char *name, int flags, Mailbox **r)
mb->mtree = avlcreate(mtreecmp);
*l = mb;
qunlock(&mbllock);
qlock(mb);
henter(PATH(0, Qtop), mb->name,
(Qid){PATH(mb->id, Qmbox), mb->vers, QTDIR}, nil, mb);
if(mb->ctl)
@ -240,8 +232,6 @@ newmbox(char *path, char *name, int flags, Mailbox **r)
rv = syncmbox(mb, 0);
if(r)
*r = mb;
else
qunlock(mb);
return rv;
}
@ -252,7 +242,6 @@ freembox(char *name)
{
Mailbox **l, *mb;
qlock(&mbllock);
for(l=&mbl; *l != nil; l=&(*l)->next)
if(strcmp(name, (*l)->name) == 0){
mb = *l;
@ -261,7 +250,6 @@ freembox(char *name)
break;
}
hfree(PATH(0, Qtop), name);
qunlock(&mbllock);
}
void
@ -270,14 +258,9 @@ syncallmboxes(void)
char *err;
Mailbox *m;
qlock(&mbllock);
for(m = mbl; m != nil; m = m->next){
qlock(m);
for(m = mbl; m != nil; m = m->next)
if(err = syncmbox(m, 1))
eprint("syncmbox: %s\n", err);
qunlock(m);
}
qunlock(&mbllock);
}
@ -288,7 +271,6 @@ removembox(char *name, int flags)
Mailbox **l, *mb;
found = 0;
qlock(&mbllock);
for(l=&mbl; *l != nil; l=&(*l)->next)
if(strcmp(name, (*l)->path) == 0){
mb = *l;
@ -300,7 +282,6 @@ removembox(char *name, int flags)
break;
}
hfree(PATH(0, Qtop), name);
qunlock(&mbllock);
if(found == 0)
return "maibox not found";
@ -1065,13 +1046,9 @@ delmessages(int ac, char **av)
Mailbox *mb;
Message *m;
qlock(&mbllock);
for(mb = mbl; mb != nil; mb = mb->next)
if(strcmp(av[0], mb->name) == 0){
qlock(mb);
if(strcmp(av[0], mb->name) == 0)
break;
}
qunlock(&mbllock);
if(mb == nil)
return "no such mailbox";
@ -1089,7 +1066,6 @@ delmessages(int ac, char **av)
}
if(needwrite)
syncmbox(mb, 1);
qunlock(mb);
return 0;
}
@ -1103,13 +1079,9 @@ flagmessages(int argc, char **argv)
if(argc%2)
return "bad flags";
qlock(&mbllock);
for(mb = mbl; mb; mb = mb->next)
if(strcmp(*argv, mb->name) == 0){
qlock(mb);
if(strcmp(*argv, mb->name) == 0)
break;
}
qunlock(&mbllock);
if(mb == nil)
return "no such mailbox";
needwrite = 0;
@ -1124,13 +1096,9 @@ flagmessages(int argc, char **argv)
}
if(needwrite)
syncmbox(mb, 1);
qunlock(mb);
return rerr;
}
/*
* the following are called with the mailbox qlocked
*/
void
msgincref(Message *m)
{
@ -1140,7 +1108,6 @@ msgincref(Message *m)
void
msgdecref(Mailbox *mb, Message *m)
{
assert(!canqlock(mb));
assert(m->refs > 0);
m->refs--;
if(m->refs == 0){
@ -1151,9 +1118,6 @@ msgdecref(Mailbox *mb, Message *m)
}
}
/*
* the following are called with mbllock'd
*/
void
mboxincref(Mailbox *mb)
{
@ -1177,7 +1141,6 @@ mbrmidx(char *path, int flags)
void
mboxdecref(Mailbox *mb)
{
qlock(mb);
assert(mb->refs > 0);
mb->refs--;
if(mb->refs == 0){
@ -1193,8 +1156,7 @@ mboxdecref(Mailbox *mb)
free(mb->mtree);
free(mb->d);
free(mb);
} else
qunlock(mb);
}
}