NFSv4.1: Ensure state manager thread dies on last umount

commit 47c2199b upstream.

Currently, the state manager may continue to try recovering state forever
even after the last filesystem to reference that nfs_client has umounted.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

fs/nfs/nfs4state.c

@@ -1228,7 +1228,7 @@ static void nfs4_state_manager(struct nfs_client *clp)
 	int status = 0;
 
 	/* Ensure exclusive access to NFSv4 state */
-	for(;;) {
+	do {
 		if (test_and_clear_bit(NFS4CLNT_LEASE_EXPIRED, &clp->cl_state)) {
 			/* We're going to have to re-establish a clientid */
 			status = nfs4_reclaim_lease(clp);
@@ -1304,7 +1304,7 @@ static void nfs4_state_manager(struct nfs_client *clp)
 			break;
 		if (test_and_set_bit(NFS4CLNT_MANAGER_RUNNING, &clp->cl_state) != 0)
 			break;
-	}
+	} while (atomic_read(&clp->cl_count) > 1);
 	return;
 out_error:
 	printk(KERN_WARNING "Error: state manager failed on NFSv4 server %s"