NFSv4: State recovery cleanup

 Use wait_on_bit() when waiting for state recovery to complete.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4_fs.h

@@ -38,7 +38,7 @@ struct idmap;
  ((err) != NFSERR_NOFILEHANDLE))
 
 enum nfs4_client_state {
-	NFS4CLNT_OK  = 0,
+	NFS4CLNT_STATE_RECOVER  = 0,
 };
 
 /*
@@ -76,7 +76,6 @@ struct nfs4_client {
 	struct work_struct	cl_renewd;
 	struct work_struct	cl_recoverd;
 
-	wait_queue_head_t	cl_waitq;
 	struct rpc_wait_queue	cl_rpcwaitq;
 
 	/* used for the setclientid verifier */

fs/nfs/nfs4proc.c

@@ -2736,7 +2736,7 @@ nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server)
 		case -NFS4ERR_EXPIRED:
 			rpc_sleep_on(&clp->cl_rpcwaitq, task, NULL, NULL);
 			nfs4_schedule_state_recovery(clp);
-			if (test_bit(NFS4CLNT_OK, &clp->cl_state))
+			if (test_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) == 0)
 				rpc_wake_up_task(task);
 			task->tk_status = 0;
 			return -EAGAIN;
@@ -2753,25 +2753,25 @@ nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server)
 	return 0;
 }
 
+static int nfs4_wait_bit_interruptible(void *word)
+{
+	if (signal_pending(current))
+		return -ERESTARTSYS;
+	schedule();
+	return 0;
+}
+
 static int nfs4_wait_clnt_recover(struct rpc_clnt *clnt, struct nfs4_client *clp)
 {
-	DEFINE_WAIT(wait);
 	sigset_t oldset;
-	int interruptible, res = 0;
+	int res;
 
 	might_sleep();
 
 	rpc_clnt_sigmask(clnt, &oldset);
-	interruptible = TASK_UNINTERRUPTIBLE;
-	if (clnt->cl_intr)
-		interruptible = TASK_INTERRUPTIBLE;
-	prepare_to_wait(&clp->cl_waitq, &wait, interruptible);
-	nfs4_schedule_state_recovery(clp);
-	if (clnt->cl_intr && signalled())
-		res = -ERESTARTSYS;
-	else if (!test_bit(NFS4CLNT_OK, &clp->cl_state))
-		schedule();
-	finish_wait(&clp->cl_waitq, &wait);
+	res = wait_on_bit(&clp->cl_state, NFS4CLNT_STATE_RECOVER,
+			nfs4_wait_bit_interruptible,
+			TASK_INTERRUPTIBLE);
 	rpc_clnt_sigunmask(clnt, &oldset);
 	return res;
 }
@@ -2814,6 +2814,7 @@ int nfs4_handle_exception(const struct nfs_server *server, int errorcode, struct
 		case -NFS4ERR_STALE_CLIENTID:
 		case -NFS4ERR_STALE_STATEID:
 		case -NFS4ERR_EXPIRED:
+			nfs4_schedule_state_recovery(clp);
 			ret = nfs4_wait_clnt_recover(server->client, clp);
 			if (ret == 0)
 				exception->retry = 1;

fs/nfs/nfs4state.c

@@ -106,11 +106,10 @@ nfs4_alloc_client(struct in_addr *addr)
 	INIT_WORK(&clp->cl_recoverd, nfs4_recover_state, clp);
 	INIT_WORK(&clp->cl_renewd, nfs4_renew_state, clp);
 	INIT_LIST_HEAD(&clp->cl_superblocks);
-	init_waitqueue_head(&clp->cl_waitq);
 	rpc_init_wait_queue(&clp->cl_rpcwaitq, "NFS4 client");
 	clp->cl_rpcclient = ERR_PTR(-EINVAL);
 	clp->cl_boot_time = CURRENT_TIME;
-	clp->cl_state = 1 << NFS4CLNT_OK;
+	clp->cl_state = 0;
 	return clp;
 }
 
@@ -193,7 +192,6 @@ nfs4_put_client(struct nfs4_client *clp)
 	list_del(&clp->cl_servers);
 	spin_unlock(&state_spinlock);
 	BUG_ON(!list_empty(&clp->cl_superblocks));
-	wake_up_all(&clp->cl_waitq);
 	rpc_wake_up(&clp->cl_rpcwaitq);
 	nfs4_kill_renewd(clp);
 	nfs4_free_client(clp);
@@ -741,6 +739,15 @@ struct reclaimer_args {
 	struct completion complete;
 };
 
+static inline void nfs4_clear_recover_bit(struct nfs4_client *clp)
+{
+	smp_mb__before_clear_bit();
+	clear_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state);
+	smp_mb__after_clear_bit();
+	wake_up_bit(&clp->cl_state, NFS4CLNT_STATE_RECOVER);
+	rpc_wake_up(&clp->cl_rpcwaitq);
+}
+
 /*
  * State recovery routine
  */
@@ -760,9 +767,7 @@ nfs4_recover_state(void *data)
 	wait_for_completion(&args.complete);
 	return;
 out_failed_clear:
-	set_bit(NFS4CLNT_OK, &clp->cl_state);
-	wake_up_all(&clp->cl_waitq);
-	rpc_wake_up(&clp->cl_rpcwaitq);
+	nfs4_clear_recover_bit(clp);
 }
 
 /*
@@ -773,7 +778,7 @@ nfs4_schedule_state_recovery(struct nfs4_client *clp)
 {
 	if (!clp)
 		return;
-	if (test_and_clear_bit(NFS4CLNT_OK, &clp->cl_state))
+	if (test_and_set_bit(NFS4CLNT_STATE_RECOVER, &clp->cl_state) == 0)
 		schedule_work(&clp->cl_recoverd);
 }
 
@@ -943,13 +948,11 @@ static int reclaimer(void *ptr)
 	}
 	nfs_delegation_reap_unclaimed(clp);
 out:
-	set_bit(NFS4CLNT_OK, &clp->cl_state);
 	up_write(&clp->cl_sem);
 	unlock_kernel();
-	wake_up_all(&clp->cl_waitq);
-	rpc_wake_up(&clp->cl_rpcwaitq);
 	if (status == -NFS4ERR_CB_PATH_DOWN)
 		nfs_handle_cb_pathdown(clp);
+	nfs4_clear_recover_bit(clp);
 	nfs4_put_client(clp);
 	return 0;
 out_error: