9p: Make sure we are able to clunk the cached fid on umount

dcache prune happen on umount. So we cannot mark the client
satus disconnect. That will prevent a 9p call to the server
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

fs/9p/v9fs.c

@@ -342,6 +342,19 @@ void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 	p9_client_disconnect(v9ses->clnt);
 }
 
+/**
+ * v9fs_session_begin_cancel - Begin terminate of a session
+ * @v9ses: session to terminate
+ *
+ * After this call we don't allow any request other than clunk.
+ */
+
+void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses)
+{
+	P9_DPRINTK(P9_DEBUG_ERROR, "begin cancel session %p\n", v9ses);
+	p9_client_begin_disconnect(v9ses->clnt);
+}
+
 extern int v9fs_error_init(void);
 
 static struct kobject *v9fs_kobj;

fs/9p/v9fs.h

@@ -108,6 +108,7 @@ struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,
 									char *);
 void v9fs_session_close(struct v9fs_session_info *v9ses);
 void v9fs_session_cancel(struct v9fs_session_info *v9ses);
+void v9fs_session_begin_cancel(struct v9fs_session_info *v9ses);
 
 #define V9FS_MAGIC 0x01021997
 

fs/9p/vfs_super.c

@@ -193,6 +193,7 @@ static void v9fs_kill_super(struct super_block *s)
 
 	kill_anon_super(s);
 
+	v9fs_session_cancel(v9ses);
 	v9fs_session_close(v9ses);
 	kfree(v9ses);
 	s->s_fs_info = NULL;
@@ -205,7 +206,7 @@ v9fs_umount_begin(struct super_block *sb)
 	struct v9fs_session_info *v9ses;
 
 	v9ses = sb->s_fs_info;
-	v9fs_session_cancel(v9ses);
+	v9fs_session_begin_cancel(v9ses);
 }
 
 static const struct super_operations v9fs_super_ops = {

include/net/9p/client.h

@@ -54,6 +54,7 @@ enum p9_proto_versions{
 
 enum p9_trans_status {
 	Connected,
+	BeginDisconnect,
 	Disconnected,
 	Hung,
 };
@@ -198,6 +199,7 @@ int p9_client_version(struct p9_client *);
 struct p9_client *p9_client_create(const char *dev_name, char *options);
 void p9_client_destroy(struct p9_client *clnt);
 void p9_client_disconnect(struct p9_client *clnt);
+void p9_client_begin_disconnect(struct p9_client *clnt);
 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 					char *uname, u32 n_uname, char *aname);
 struct p9_fid *p9_client_auth(struct p9_client *clnt, char *uname,

net/9p/client.c

@@ -533,7 +533,12 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
 
 	P9_DPRINTK(P9_DEBUG_MUX, "client %p op %d\n", c, type);
 
-	if (c->status != Connected)
+	/* we allow for any status other than disconnected */
+	if (c->status == Disconnected)
+		return ERR_PTR(-EIO);
+
+	/* if status is begin_disconnected we allow only clunk request */
+	if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
 		return ERR_PTR(-EIO);
 
 	if (signal_pending(current)) {
@@ -799,8 +804,10 @@ void p9_client_destroy(struct p9_client *clnt)
 
 	v9fs_put_trans(clnt->trans_mod);
 
-	list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist)
+	list_for_each_entry_safe(fid, fidptr, &clnt->fidlist, flist) {
+		printk(KERN_INFO "Found fid %d not clunked\n", fid->fid);
 		p9_fid_destroy(fid);
+	}
 
 	if (clnt->fidpool)
 		p9_idpool_destroy(clnt->fidpool);
@@ -818,6 +825,13 @@ void p9_client_disconnect(struct p9_client *clnt)
 }
 EXPORT_SYMBOL(p9_client_disconnect);
 
+void p9_client_begin_disconnect(struct p9_client *clnt)
+{
+	P9_DPRINTK(P9_DEBUG_9P, "clnt %p\n", clnt);
+	clnt->status = BeginDisconnect;
+}
+EXPORT_SYMBOL(p9_client_begin_disconnect);
+
 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 	char *uname, u32 n_uname, char *aname)
 {