diff --git a/fs/afs/cmservice.c b/fs/afs/cmservice.c
index b378cd780ed5..fc5eb0f89304 100644
--- a/fs/afs/cmservice.c
+++ b/fs/afs/cmservice.c
@@ -169,7 +169,7 @@ static int afs_record_cm_probe(struct afs_call *call, struct afs_server *server)
 
 	spin_lock(&server->probe_lock);
 
-	if (!test_bit(AFS_SERVER_FL_HAVE_EPOCH, &server->flags)) {
+	if (!test_and_set_bit(AFS_SERVER_FL_HAVE_EPOCH, &server->flags)) {
 		server->cm_epoch = call->epoch;
 		server->probe.cm_epoch = call->epoch;
 		goto out;