nfs: allow to specify cred in nfs_initiate_pgio

so that flexfile layout client can pass in DS credential instead of
using user cred, which will be done in the next patch.

Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>
diff --git a/fs/nfs/filelayout/filelayout.c b/fs/nfs/filelayout/filelayout.c
index e5a3c5b..bfa8547 100644
--- a/fs/nfs/filelayout/filelayout.c
+++ b/fs/nfs/filelayout/filelayout.c
@@ -501,8 +501,9 @@
 	hdr->mds_offset = offset;
 
 	/* Perform an asynchronous read to ds */
-	nfs_initiate_pgio(ds_clnt, hdr, NFS_PROTO(hdr->inode),
-			    &filelayout_read_call_ops, 0, RPC_TASK_SOFTCONN);
+	nfs_initiate_pgio(ds_clnt, hdr, hdr->cred,
+			  NFS_PROTO(hdr->inode), &filelayout_read_call_ops,
+			  0, RPC_TASK_SOFTCONN);
 	return PNFS_ATTEMPTED;
 }
 
@@ -542,9 +543,9 @@
 	hdr->args.offset = filelayout_get_dserver_offset(lseg, offset);
 
 	/* Perform an asynchronous write */
-	nfs_initiate_pgio(ds_clnt, hdr, NFS_PROTO(hdr->inode),
-				    &filelayout_write_call_ops, sync,
-				    RPC_TASK_SOFTCONN);
+	nfs_initiate_pgio(ds_clnt, hdr, hdr->cred,
+			  NFS_PROTO(hdr->inode), &filelayout_write_call_ops,
+			  sync, RPC_TASK_SOFTCONN);
 	return PNFS_ATTEMPTED;
 }