NFS: callback per-net usage counting introduced

This patch also introduces refcount-aware nfs_callback_down_net() wrapper for
svc_shutdown_net().

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index baafa0f..6dfdc83 100644 (file)
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -260,10 +260,25 @@ static int nfs_callback_start_svc(int minorversion, struct rpc_xprt *xprt,
        return 0;
 }
 
+static void nfs_callback_down_net(u32 minorversion, struct svc_serv *serv, struct net *net)
+{
+       struct nfs_net *nn = net_generic(net, nfs_net_id);
+
+       if (--nn->cb_users[minorversion])
+               return;
+
+       dprintk("NFS: destroy per-net callback data; net=%p\n", net);
+       svc_shutdown_net(serv, net);
+}
+
 static int nfs_callback_up_net(int minorversion, struct svc_serv *serv, struct net *net)
 {
+       struct nfs_net *nn = net_generic(net, nfs_net_id);
        int ret;
 
+       if (nn->cb_users[minorversion]++)
+               return 0;
+
        dprintk("NFS: create per-net callback data; net=%p\n", net);
 
        ret = svc_bind(serv, net);
@@ -378,7 +393,7 @@ err_create:
        return ret;
 
 err_start:
-       svc_shutdown_net(serv, net);
+       nfs_callback_down_net(minorversion, serv, net);
        dprintk("NFS: Couldn't create server thread; err = %d\n", ret);
        goto err_net;
 }
@@ -391,10 +406,10 @@ void nfs_callback_down(int minorversion, struct net *net)
        struct nfs_callback_data *cb_info = &nfs_callback_info[minorversion];
 
        mutex_lock(&nfs_callback_mutex);
+       nfs_callback_down_net(minorversion, cb_info->serv, net);
        cb_info->users--;
        if (cb_info->users == 0 && cb_info->task != NULL) {
                kthread_stop(cb_info->task);
-               svc_shutdown_net(cb_info->serv, net);
                svc_exit_thread(cb_info->rqst);
                cb_info->serv = NULL;
                cb_info->rqst = NULL;

diff --git a/fs/nfs/netns.h b/fs/nfs/netns.h
index 137238b..b9c7f9b 100644 (file)
--- a/fs/nfs/netns.h
+++ b/fs/nfs/netns.h
@@ -24,6 +24,7 @@ struct nfs_net {
        struct idr cb_ident_idr; /* Protected by nfs_client_lock */
        unsigned short nfs_callback_tcpport;
        unsigned short nfs_callback_tcpport6;
+       int cb_users[NFS4_MAX_MINOR_VERSION + 1];
 #endif
        spinlock_t nfs_client_lock;
        struct timespec boot_time;