1 files changed, 32 insertions, 47 deletions

diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c
index 5c21caeae075..97abf62f109d 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 ||
@@ -180,10 +180,8 @@ void nfs_local_probe(struct nfs_client *clp)
 		return;
 	}
 
-	if (nfs_client_is_local(clp)) {
-		/* If already enabled, disable and re-enable */
-		nfs_localio_disable_client(clp);
-	}
+	if (nfs_client_is_local(clp))
+		return;
 
 	if (!nfs_uuid_begin(&clp->cl_uuid))
 		return;
@@ -191,14 +189,16 @@ 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 +207,16 @@ 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 +228,13 @@ 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);
@@ -239,7 +242,8 @@ __nfs_local_open_fh(struct nfs_client *clp, const struct cred *cred,
 		case -ENOMEM:
 		case -ENXIO:
 		case -ENOENT:
-			/* Revalidate localio, will disable if unsupported */
+			/* Revalidate localio */
+			nfs_localio_disable_client(clp);
 			nfs_local_probe(clp);
 		}
 	}
@@ -258,7 +262,7 @@ 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 +274,9 @@ 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;
-		/* 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);
-		rcu_read_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);
@@ -468,12 +452,13 @@ static void nfs_local_call_read(struct work_struct *work)
 	nfs_local_iter_init(&iter, iocb, READ);
 
 	status = filp->f_op->read_iter(&iocb->kiocb, &iter);
+
+	revert_creds(save_cred);
+
 	if (status != -EIOCBQUEUED) {
 		nfs_local_read_done(iocb, status);
 		nfs_local_pgio_release(iocb);
 	}
-
-	revert_creds(save_cred);
 }
 
 static int
@@ -515,14 +500,13 @@ nfs_copy_boot_verifier(struct nfs_write_verifier *verifier, struct inode *inode)
 {
 	struct nfs_client *clp = NFS_SERVER(inode)->nfs_client;
 	u32 *verf = (u32 *)verifier->data;
-	int seq = 0;
+	unsigned int seq;
 
 	do {
-		read_seqbegin_or_lock(&clp->cl_boot_lock, &seq);
+		seq = read_seqbegin(&clp->cl_boot_lock);
 		verf[0] = (u32)clp->cl_nfssvc_boot.tv_sec;
 		verf[1] = (u32)clp->cl_nfssvc_boot.tv_nsec;
-	} while (need_seqretry(&clp->cl_boot_lock, seq));
-	done_seqretry(&clp->cl_boot_lock, seq);
+	} while (read_seqretry(&clp->cl_boot_lock, seq));
 }
 
 static void
@@ -664,14 +648,15 @@ static void nfs_local_call_write(struct work_struct *work)
 	file_start_write(filp);
 	status = filp->f_op->write_iter(&iocb->kiocb, &iter);
 	file_end_write(filp);
+
+	revert_creds(save_cred);
+	current->flags = old_flags;
+
 	if (status != -EIOCBQUEUED) {
 		nfs_local_write_done(iocb, status);
 		nfs_local_vfs_getattr(iocb);
 		nfs_local_pgio_release(iocb);
 	}
-
-	revert_creds(save_cred);
-	current->flags = old_flags;
 }
 
 static int