1 files changed, 18 insertions, 33 deletions

diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c
index 4ec952f9f47d..510d0a16cfe9 100644
--- a/fs/nfs/localio.c
+++ b/fs/nfs/localio.c
@@ -171,7 +171,7 @@ static bool nfs_server_uuid_is_local(struct nfs_client *clp)
  * - called after alloc_client and init_client (so cl_rpcclient exists)
  * - this function is idempotent, it can be called for old or new clients
  */
-void nfs_local_probe(struct nfs_client *clp)
+static void nfs_local_probe(struct nfs_client *clp)
 {
 	/* Disallow localio if disabled via sysfs or AUTH_SYS isn't used */
 	if (!localio_enabled ||
@@ -191,14 +191,16 @@ void nfs_local_probe(struct nfs_client *clp)
 		nfs_localio_enable_client(clp);
 	nfs_uuid_end(&clp->cl_uuid);
 }
-EXPORT_SYMBOL_GPL(nfs_local_probe);
 
 void nfs_local_probe_async_work(struct work_struct *work)
 {
 	struct nfs_client *clp =
 		container_of(work, struct nfs_client, cl_local_probe_work);
 
+	if (!refcount_inc_not_zero(&clp->cl_count))
+		return;
 	nfs_local_probe(clp);
+	nfs_put_client(clp);
 }
 
 void nfs_local_probe_async(struct nfs_client *clp)
@@ -207,14 +209,16 @@ void nfs_local_probe_async(struct nfs_client *clp)
 }
 EXPORT_SYMBOL_GPL(nfs_local_probe_async);
 
-static inline struct nfsd_file *nfs_local_file_get(struct nfsd_file *nf)
+static inline void nfs_local_file_put(struct nfsd_file *localio)
 {
-	return nfs_to->nfsd_file_get(nf);
-}
+	/* nfs_to_nfsd_file_put_local() expects an __rcu pointer
+	 * but we have a __kernel pointer.  It is always safe
+	 * to cast a __kernel pointer to an __rcu pointer
+	 * because the cast only weakens what is known about the pointer.
+	 */
+	struct nfsd_file __rcu *nf = (struct nfsd_file __rcu*) localio;
 
-static inline void nfs_local_file_put(struct nfsd_file *nf)
-{
-	nfs_to->nfsd_file_put(nf);
+	nfs_to_nfsd_file_put_local(&nf);
 }
 
 /*
@@ -226,12 +230,13 @@ static inline void nfs_local_file_put(struct nfsd_file *nf)
 static struct nfsd_file *
 __nfs_local_open_fh(struct nfs_client *clp, const struct cred *cred,
 		    struct nfs_fh *fh, struct nfs_file_localio *nfl,
+		    struct nfsd_file __rcu **pnf,
 		    const fmode_t mode)
 {
 	struct nfsd_file *localio;
 
 	localio = nfs_open_local_fh(&clp->cl_uuid, clp->cl_rpcclient,
-				    cred, fh, nfl, mode);
+				    cred, fh, nfl, pnf, mode);
 	if (IS_ERR(localio)) {
 		int status = PTR_ERR(localio);
 		trace_nfs_local_open_fh(fh, mode, status);
@@ -258,7 +263,7 @@ nfs_local_open_fh(struct nfs_client *clp, const struct cred *cred,
 		  struct nfs_fh *fh, struct nfs_file_localio *nfl,
 		  const fmode_t mode)
 {
-	struct nfsd_file *nf, *new, __rcu **pnf;
+	struct nfsd_file *nf, __rcu **pnf;
 
 	if (!nfs_server_is_local(clp))
 		return NULL;
@@ -270,29 +275,9 @@ nfs_local_open_fh(struct nfs_client *clp, const struct cred *cred,
 	else
 		pnf = &nfl->ro_file;
 
-	new = NULL;
-	rcu_read_lock();
-	nf = rcu_dereference(*pnf);
-	if (!nf) {
-		rcu_read_unlock();
-		new = __nfs_local_open_fh(clp, cred, fh, nfl, mode);
-		if (IS_ERR(new))
-			return NULL;
-		rcu_read_lock();
-		/* try to swap in the pointer */
-		spin_lock(&clp->cl_uuid.lock);
-		nf = rcu_dereference_protected(*pnf, 1);
-		if (!nf) {
-			nf = new;
-			new = NULL;
-			rcu_assign_pointer(*pnf, nf);
-		}
-		spin_unlock(&clp->cl_uuid.lock);
-	}
-	nf = nfs_local_file_get(nf);
-	rcu_read_unlock();
-	if (new)
-		nfs_to_nfsd_file_put_local(new);
+	nf = __nfs_local_open_fh(clp, cred, fh, nfl, pnf, mode);
+	if (IS_ERR(nf))
+		return NULL;
 	return nf;
 }
 EXPORT_SYMBOL_GPL(nfs_local_open_fh);