upas/fs: don't enter mailbox into hashtree when it is being freed

syncmbox() used to enter the mailbox into the hash tree to
update the qid.vers. this is wrong when we are doing the final
sync before freeing the mailbox as the hash reference has already
been removed by freemailbox().

also avoid adding hash entries for mails for the about to be
freed mailbox in cachehash().

2 files changed, 9 insertions, 5 deletions

diff --git a/sys/src/cmd/upas/fs/cache.c b/sys/src/cmd/upas/fs/cache.c
index 6620670fa..ab9b0d252 100644
--- a/sys/src/cmd/upas/fs/cache.c
+++ b/sys/src/cmd/upas/fs/cache.c
@@ -216,6 +216,9 @@ top:
 void
 cachehash(Mailbox *mb, Message *m)
 {
+	assert(mb->refs >= 0);
+	if(mb->refs == 0)
+		return;
 	if(m->whole == m->whole->whole)
 		henter(PATH(mb->id, Qmbox), m->name,
 			(Qid){PATH(m->id, Qdir), 0, QTDIR}, m, mb);
diff --git a/sys/src/cmd/upas/fs/mbox.c b/sys/src/cmd/upas/fs/mbox.c
index a77996fd4..87e03d65f 100644
--- a/sys/src/cmd/upas/fs/mbox.c
+++ b/sys/src/cmd/upas/fs/mbox.c
@@ -115,14 +115,15 @@ syncmbox(Mailbox *mb, int doplumb)
 	a = mb->root->subname - a;
 	assert(a >= 0);
 	if(n + d + y + a){
+		Hash *h;
+
 		iprint("deleted: %d; new %d; stale %d\n", d, n, y);
 		logmsg(nil, "deleted: %d; new %d; stale %d", d, n, y);
 		wridxfile(mb);
-	}
-	if(n + d + y + a){
+
 		mb->vers++;
-		henter(PATH(0, Qtop), mb->name,
-			(Qid){PATH(mb->id, Qmbox), mb->vers, QTDIR}, nil, mb);
+		if(mb->refs > 0 && (h = hlook(PATH(0, Qtop), mb->name)) != nil && h->mb == mb)
+			h->qid.vers = mb->vers;
 	}
 
 	mb->syncing = 0;
@@ -166,8 +167,8 @@ mboxrename(char *a, char *b, int flags)
 	strcat(f1, ".imp");
 	rename(f0, f1, 0);
 
-	snprint(mb->path, sizeof mb->path, "%s", b);
 	hfree(PATH(0, Qtop), mb->name);
+	snprint(mb->path, sizeof mb->path, "%s", b);
 	p0 = strrchr(mb->path, '/') + 1;
 	if(p0 == (char*)1)
 		p0 = mb->path;