NFSv4.1 return the LAYOUT for each file with failed DS connection I/O

First mark the deviceid invalid to prevent any future use. Then fence all
files involved in I/O to a DS with a connection error by sending a
LAYOUTRETURN.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4filelayout.c

@@ -205,9 +205,8 @@ static int filelayout_async_handle_error(struct rpc_task *task,
 	case -EPIPE:
 		dprintk("%s DS connection error %d\n", __func__,
 			task->tk_status);
-		if (!filelayout_test_devid_invalid(devid))
-			_pnfs_return_layout(inode);
 		filelayout_mark_devid_invalid(devid);
+		_pnfs_return_layout(inode);
 		rpc_wake_up(&tbl->slot_tbl_waitq);
 		nfs4_ds_disconnect(clp);
 		/* fall through */