nfsd: move reply cache initialization into nfsd startup

There's no need to start the reply cache before nfsd is up and running,
and doing so means that we register a shrinker for every net namespace
instead of just the ones where nfsd is running.

Move it to the per-net nfsd startup instead.
Reported-by: Dai Ngo <dai.ngo@oracle.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfsctl.c

@@ -1458,16 +1458,11 @@ static __net_init int nfsd_init_net(struct net *net)
 	nn->nfsd_versions = NULL;
 	nn->nfsd4_minorversions = NULL;
 	nfsd4_init_leases_net(nn);
-	retval = nfsd_reply_cache_init(nn);
-	if (retval)
-		goto out_cache_error;
 	get_random_bytes(&nn->siphash_key, sizeof(nn->siphash_key));
 	seqlock_init(&nn->writeverf_lock);
 
 	return 0;
 
-out_cache_error:
-	nfsd_idmap_shutdown(net);
 out_idmap_error:
 	nfsd_export_shutdown(net);
 out_export_error:
@@ -1476,9 +1471,6 @@ static __net_init int nfsd_init_net(struct net *net)
 
 static __net_exit void nfsd_exit_net(struct net *net)
 {
-	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
-
-	nfsd_reply_cache_shutdown(nn);
 	nfsd_idmap_shutdown(net);
 	nfsd_export_shutdown(net);
 	nfsd_netns_free_versions(net_generic(net, nfsd_net_id));

fs/nfsd/nfssvc.c

@@ -427,16 +427,23 @@ static int nfsd_startup_net(struct net *net, const struct cred *cred)
 	ret = nfsd_file_cache_start_net(net);
 	if (ret)
 		goto out_lockd;
-	ret = nfs4_state_start_net(net);
+
+	ret = nfsd_reply_cache_init(nn);
 	if (ret)
 		goto out_filecache;
 
+	ret = nfs4_state_start_net(net);
+	if (ret)
+		goto out_reply_cache;
+
 #ifdef CONFIG_NFSD_V4_2_INTER_SSC
 	nfsd4_ssc_init_umount_work(nn);
 #endif
 	nn->nfsd_net_up = true;
 	return 0;
 
+out_reply_cache:
+	nfsd_reply_cache_shutdown(nn);
 out_filecache:
 	nfsd_file_cache_shutdown_net(net);
 out_lockd:
@@ -454,6 +461,7 @@ static void nfsd_shutdown_net(struct net *net)
 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
 
 	nfs4_state_shutdown_net(net);
+	nfsd_reply_cache_shutdown(nn);
 	nfsd_file_cache_shutdown_net(net);
 	if (nn->lockd_up) {
 		lockd_down(net);