Merge tag 'nfs-for-3.7-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS bugfixes from Trond Myklebust:

 - Fix the NFSv2/v3 kernel statd protocol, which broke due to net
   namespace related changes.

 - Fix a number of races in the SUNRPC TCP disconnect/reconnect code.

* tag 'nfs-for-3.7-3' of git://git.linux-nfs.org/projects/trondmy/linux-nfs:
  LOCKD: Clear ln->nsm_clnt only when ln->nsm_users is zero
  LOCKD: fix races in nsm_client_get
  SUNRPC: Get rid of the xs_error_report socket callback
  SUNRPC: Prevent races in xs_abort_connection()
  Revert "SUNRPC: Ensure we close the socket on EPIPE errors too..."
  SUNRPC: Clear the connect flag when socket state is TCP_CLOSE_WAIT

1 files changed, 32 insertions, 25 deletions

diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
index e4fb3ba5a58a..3d7e09bcc0e9 100644
--- a/fs/lockd/mon.c
+++ b/fs/lockd/mon.c
@@ -85,29 +85,38 @@ static struct rpc_clnt *nsm_create(struct net *net)
         return rpc_create(&args);
 }
 
+static struct rpc_clnt *nsm_client_set(struct lockd_net *ln,
+                struct rpc_clnt *clnt)
+{
+        spin_lock(&ln->nsm_clnt_lock);
+        if (ln->nsm_users == 0) {
+                if (clnt == NULL)
+                        goto out;
+                ln->nsm_clnt = clnt;
+        }
+        clnt = ln->nsm_clnt;
+        ln->nsm_users++;
+out:
+        spin_unlock(&ln->nsm_clnt_lock);
+        return clnt;
+}
+
 static struct rpc_clnt *nsm_client_get(struct net *net)
 {
-        static DEFINE_MUTEX(nsm_create_mutex);
-        struct rpc_clnt *clnt;
+        struct rpc_clnt *clnt, *new;
         struct lockd_net *ln = net_generic(net, lockd_net_id);
 
-        spin_lock(&ln->nsm_clnt_lock);
-        if (ln->nsm_users) {
-                ln->nsm_users++;
-                clnt = ln->nsm_clnt;
-                spin_unlock(&ln->nsm_clnt_lock);
+        clnt = nsm_client_set(ln, NULL);
+        if (clnt != NULL)
                 goto out;
-        }
-        spin_unlock(&ln->nsm_clnt_lock);
 
-        mutex_lock(&nsm_create_mutex);
-        clnt = nsm_create(net);
-        if (!IS_ERR(clnt)) {
-                ln->nsm_clnt = clnt;
-                smp_wmb();
-                ln->nsm_users = 1;
-        }
-        mutex_unlock(&nsm_create_mutex);
+        clnt = new = nsm_create(net);
+        if (IS_ERR(clnt))
+                goto out;
+
+        clnt = nsm_client_set(ln, new);
+        if (clnt != new)
+                rpc_shutdown_client(new);
 out:
         return clnt;
 }
@@ -115,18 +124,16 @@ out:
 static void nsm_client_put(struct net *net)
 {
         struct lockd_net *ln = net_generic(net, lockd_net_id);
-        struct rpc_clnt *clnt = ln->nsm_clnt;
-        int shutdown = 0;
+        struct rpc_clnt *clnt = NULL;
 
         spin_lock(&ln->nsm_clnt_lock);
-        if (ln->nsm_users) {
-                if (--ln->nsm_users)
-                        ln->nsm_clnt = NULL;
-                shutdown = !ln->nsm_users;
+        ln->nsm_users--;
+        if (ln->nsm_users == 0) {
+                clnt = ln->nsm_clnt;
+                ln->nsm_clnt = NULL;
         }
         spin_unlock(&ln->nsm_clnt_lock);
-
-        if (shutdown)
+        if (clnt != NULL)
                 rpc_shutdown_client(clnt);
 }