rio: properly handle follow up flushes (fixes unexpected reply tag)

when multiple flushes are send, they need to be replied
in order. we ensure this by having the flush xfid taking
over the flushtag (synchronized with a new fs->csyncflush
channel) so the next flush will flush the previous flush.

1 files changed, 14 insertions, 8 deletions

diff --git a/sys/src/cmd/rio/fsys.c b/sys/src/cmd/rio/fsys.c
index f4fea7723..5e680ea85 100644
--- a/sys/src/cmd/rio/fsys.c
+++ b/sys/src/cmd/rio/fsys.c
@@ -18,10 +18,6 @@ char	Eoffset[] = "illegal offset";
 
 int	messagesize = 8192+IOHDRSZ;	/* good start */
 
-enum{
-	DEBUG = 0
-};
-
 Dirtab dirtab[]=
 {
 	{ ".",			QTDIR,	Qdir,			0500|DMDIR },
@@ -142,6 +138,9 @@ filsysinit(Channel *cxfidalloc)
 		close(fd);
 	}
 	fs->user = estrdup(buf);
+	fs->csyncflush = chancreate(sizeof(int), 0);
+	if(fs->csyncflush == nil)
+		error("chancreate syncflush");
 	fs->cxfidalloc = cxfidalloc;
 	pid = getpid();
 
@@ -210,7 +209,7 @@ filsysproc(void *arg)
 		x->buf = buf;
 		if(convM2S(buf, n, x) != n)
 			error("convert error in convM2S");
-		if(DEBUG)
+		if(debug)
 			fprint(2, "rio:<-%F\n", &x->Fcall);
 		if(fcall[x->type] == nil)
 			x = filsysrespond(fs, x, &t, Ebadfcall);
@@ -266,7 +265,7 @@ filsysrespond(Filsys *fs, Xfid *x, Fcall *t, char *err)
 		error("convert error in convS2M");
 	if(write(fs->sfd, x->buf, n) != n)
 		error("write error in respond");
-	if(DEBUG)
+	if(debug)
 		fprint(2, "rio:->%F\n", t);
 	free(x->buf);
 	x->buf = nil;
@@ -307,14 +306,21 @@ filsysauth(Filsys *fs, Xfid *x, Fid*)
 {
 	Fcall t;
 
-		return filsysrespond(fs, x, &t, "rio: authentication not required");
+	return filsysrespond(fs, x, &t, "rio: authentication not required");
 }
 
 static
 Xfid*
-filsysflush(Filsys*, Xfid *x, Fid*)
+filsysflush(Filsys *fs, Xfid *x, Fid*)
 {
 	sendp(x->c, xfidflush);
+
+	/*
+	 * flushes need to be replied in order. xfidflush() will
+	 * awaken us when the flush has been queued.
+	 */
+	recv(fs->csyncflush, nil);
+
 	return nil;
 }