pNFS/flexfiles: Check the result of nfs4_pnfs_ds_connect

The check in nfs4_ff_layout_prepare_ds() seems to be missing.
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Fixes: a33e4b03 ("pNFS: return status from nfs4_pnfs_ds_connect")
Cc: Weston Andros Adamson <dros@primarydata.com>
Cc: stable@vger.kernel.org # v4.11

fs/nfs/flexfilelayout/flexfilelayoutdev.c

@@ -421,7 +421,7 @@ nfs4_ff_layout_prepare_ds(struct pnfs_layout_segment *lseg, u32 ds_idx,
 			     mirror->mirror_ds->ds_versions[0].minor_version);
 
 	/* connect success, check rsize/wsize limit */
-	if (ds->ds_clp) {
+	if (!status) {
 		max_payload =
 			nfs_block_size(rpc_max_payload(ds->ds_clp->cl_rpcclient),
 				       NULL);