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.

diff --git a/sys/src/cmd/upas/fs/dat.h b/sys/src/cmd/upas/fs/dat.h
index 0220f09dc8c793165a6463d0d1d8b8f4ec2e3cca..f955fd23cd237a7ab20f0a529548c6202a3c6277 100644 (file)
--- a/sys/src/cmd/upas/fs/dat.h
+++ b/sys/src/cmd/upas/fs/dat.h
@@ -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 {}

diff --git a/sys/src/cmd/upas/fs/fs.c b/sys/src/cmd/upas/fs/fs.c
index 880d8501fd4a5a450569fde96527c171d63284d7..d6c9b1380b100d6e1fc8abb14367bed00078c6e1 100644 (file)
--- a/sys/src/cmd/upas/fs/fs.c
+++ b/sys/src/cmd/upas/fs/fs.c
@@ -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;
@@ -1526,14 +1473,14 @@ reader(void)
                                        free(d);
                                }
                        }
-                       qunlock(mb);
                }
-               qunlock(&mbllock);
-               if(mb != nil){
+               if(mb != nil) {
                        syncmbox(mb, 1);
-                       qunlock(mb);
-               } else
+                       qunlock(&synclock);
+               } else {
+                       qunlock(&synclock);
                        sleep(15*1000);
+               }
        }
 }
 
@@ -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

diff --git a/sys/src/cmd/upas/fs/mbox.c b/sys/src/cmd/upas/fs/mbox.c
index 22a8fedc70696a214aa934c99b4786d4f29e3629..7d05ad73182f9d8f3df323ee365dd1555e5c3a96 100644 (file)
--- a/sys/src/cmd/upas/fs/mbox.c
+++ b/sys/src/cmd/upas/fs/mbox.c
@@ -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);
+       }
 }