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rio: enforce flush reply ordering for all xfids

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flushing isnt optional for concurrently handled requests.
we need to ensure that Rflush is replied *after* the
origianl request.

so we assign the flushtag for *every* xfid in xfidctl(),
and filsysrespond() checks if the xfid was flushed
*after* replying and wakes up the flushing xfid.
This commit is contained in:
cinap_lenrek 2013-11-01 21:21:24 +01:00
parent 413977c19b
commit f37ee95fbc
2 changed files with 9 additions and 11 deletions
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2
sys/src/cmd/rio/fsys.c
View file

@ -270,6 +270,8 @@ filsysrespond(Filsys *fs, Xfid *x, Fcall *t, char *err)
free(x->buf);
x->buf = nil;
x->flushtag = -1;
if(x->flushing)
recv(x->flushc, nil); /* wakeup flushing xfid */
return x;
}

18
sys/src/cmd/rio/xfid.c
View file

@ -80,6 +80,8 @@ xfidallocthread(void*)
fprint(2, "%p decref %ld\n", x, x->ref);
error("decref");
}
if(x->flushing)
error("flushing in free");
if(x->flushtag != -1)
error("flushtag in free");
x->free = xfidfree;
@ -110,6 +112,7 @@ xfidctl(void *arg)
threadsetname(buf);
for(;;){
f = recvp(x->c);
x->flushtag = x->tag;
(*f)(x);
if(decref(x) == 0)
sendp(cxfidfree, x);
@ -127,12 +130,13 @@ xfidflush(Xfid *x)
incref(xf); /* to hold data structures up at tail of synchronization */
if(xf->ref == 1)
error("ref 1 in flush");
/* take over flushtag so follow up flushes wait for us */
x->flushtag = x->oldtag;
xf->flushtag = -1;
break;
}
/* take over flushtag so follow up flushes wait for us */
x->flushtag = x->oldtag;
/*
* wakeup filsysflush() in the filsysproc so the next
* flush can come in.
@ -257,7 +261,7 @@ xfidopen(Xfid *x)
w->ctlopen = TRUE;
break;
case Qkbdin:
if(w != wkeyboard){
if(w != wkeyboard){
filsysrespond(x->fs, x, &t, Eperm);
return;
}
@ -417,7 +421,6 @@ xfidwrite(Xfid *x)
memmove(x->f->rpart, x->data+nb, cnt-nb);
x->f->nrpart = cnt-nb;
}
x->flushtag = x->tag;
alts[CWdata].c = w->conswrite;
alts[CWdata].v = &cwm;
@ -658,8 +661,6 @@ xfidread(Xfid *x)
cnt = x->count;
switch(qid){
case Qcons:
x->flushtag = x->tag;
alts[CRdata].c = w->consread;
alts[CRdata].v = &crm;
alts[CRdata].op = CHANRCV;
@ -725,8 +726,6 @@ xfidread(Xfid *x)
break;
case Qmouse:
x->flushtag = x->tag;
alts[MRdata].c = w->mouseread;
alts[MRdata].v = &mrm;
alts[MRdata].op = CHANRCV;
@ -778,8 +777,6 @@ xfidread(Xfid *x)
break;
case Qkbd:
x->flushtag = x->tag;
alts[MRdata].c = w->kbdread;
alts[MRdata].v = &krm;
alts[MRdata].op = CHANRCV;
@ -919,7 +916,6 @@ xfidread(Xfid *x)
filsysrespond(x->fs, x, &fc, Etooshort);
break;
}
x->flushtag = x->tag;
alts[WCRdata].c = w->wctlread;
alts[WCRdata].v = &cwrm;