diff --git a/sys/src/9/port/cache.c b/sys/src/9/port/cache.c
index 306228731..37a4d6813 100644
--- a/sys/src/9/port/cache.c
+++ b/sys/src/9/port/cache.c
@@ -187,7 +187,7 @@ ccache(Chan *c)
 	return nil;
 }
 
-void
+int
 copen(Chan *c)
 {
 	Mntcache *m, *f, **l;
@@ -195,19 +195,20 @@ copen(Chan *c)
 	/* directories aren't cacheable */
 	if(c->qid.type&QTDIR){
 		c->mcp = nil;
-		return;
+		return 0;
 	}
 
 	lock(&cache);
-	m = clookup(c, 1);
-	if(m == nil)
-		m = cache.head;
-	else if(m->qid.vers == c->qid.vers) {
+	m = clookup(c, 0);
+	if(m != nil){
 		ctail(m);
 		unlock(&cache);
 		c->mcp = m;
-		return;
+		return 1;
 	}
+	m = clookup(c, 1);
+	if(m == nil)
+		m = cache.head;
 	ctail(m);
 
 	l = &cache.hash[m->qid.path%NHASH];
@@ -234,7 +235,7 @@ copen(Chan *c)
 			unlock(&cache);
 			cacheunlock(m);
 			c->mcp = f;
-			return;
+			return 1;
 		}
 	}
 
@@ -251,10 +252,9 @@ copen(Chan *c)
 	m->rah.vers = m->qid.vers;
 	mntrahinit(&m->rah);
 	cnodata(m);
-
 	cacheunlock(m);
-
 	c->mcp = m;
+	return 0;
 }
 
 enum {
@@ -482,6 +482,31 @@ cwrite(Chan* c, uchar *buf, int len, vlong off)
 	cachedata(m, buf, len, off);
 }
 
+void
+ctrunc(Chan *c)
+{
+	Mntcache *m;
+
+	if(c->qid.type&QTDIR)
+		return;
+
+	if((c->flag&COPEN) == 0){
+		lock(&cache);
+		c->mcp = clookup(c, 0);
+		unlock(&cache);
+	}
+
+	m = ccache(c);
+	if(m == nil)
+		return;
+	mntrahinit(&m->rah);
+	cnodata(m);
+	cacheunlock(m);
+
+	if((c->flag&COPEN) == 0)
+		c->mcp = nil;
+}
+
 void
 cclunk(Chan *c)
 {
diff --git a/sys/src/9/port/devmnt.c b/sys/src/9/port/devmnt.c
index 095381d57..fc5ccbf1e 100644
--- a/sys/src/9/port/devmnt.c
+++ b/sys/src/9/port/devmnt.c
@@ -521,8 +521,11 @@ mntopencreate(int type, Chan *c, char *name, int omode, ulong perm)
 	poperror();
 	mntfree(r);
 
-	if(c->flag & CCACHE)
-		copen(c);
+	if(c->flag & CCACHE){
+		if(copen(c))
+		if(type == Tcreate || (omode&OTRUNC) != 0)
+			ctrunc(c);
+	}
 
 	return c;
 }
@@ -620,6 +623,11 @@ mntwstat(Chan *c, uchar *dp, int n)
 	mountrpc(m, r);
 	poperror();
 	mntfree(r);
+
+	if(c->flag & CCACHE)
+	if(GBIT64(&dp[STATFIXLEN-4*BIT16SZ-BIT64SZ]) != ~0ULL)
+		ctrunc(c);
+
 	return n;
 }
 
diff --git a/sys/src/9/port/portfns.h b/sys/src/9/port/portfns.h
index 7c7eec461..5564ce0c8 100644
--- a/sys/src/9/port/portfns.h
+++ b/sys/src/9/port/portfns.h
@@ -41,13 +41,14 @@ void		confinit(void);
 int		consactive(void);
 void		(*consdebug)(void);
 void		cpushutdown(void);
-void		copen(Chan*);
+int		copen(Chan*);
 void		cclunk(Chan*);
 Block*		concatblock(Block*);
 Block*		copyblock(Block*, int);
 void		copypage(Page*, Page*);
 void		countpagerefs(ulong*, int);
 int		cread(Chan*, uchar*, int, vlong);
+void		ctrunc(Chan*);
 void		cunmount(Chan*, Chan*);
 void		cupdate(Chan*, uchar*, int, vlong);
 void		cwrite(Chan*, uchar*, int, vlong);