nfs41: pass iomode through layoutreturn args

So that it is possible to return a specific iomode layouts.
Signed-off-by: Peng Tao <tao.peng@primarydata.com>
Signed-off-by: Tom Haynes <Thomas.Haynes@primarydata.com>

fs/nfs/nfs4xdr.c

@@ -2012,7 +2012,7 @@ encode_layoutreturn(struct xdr_stream *xdr,
 	p = reserve_space(xdr, 16);
 	*p++ = cpu_to_be32(0);		/* reclaim. always 0 for now */
 	*p++ = cpu_to_be32(args->layout_type);
-	*p++ = cpu_to_be32(IOMODE_ANY);
+	*p++ = cpu_to_be32(args->iomode);
 	*p = cpu_to_be32(RETURN_FILE);
 	p = reserve_space(xdr, 16);
 	p = xdr_encode_hyper(p, 0);

fs/nfs/pnfs.c

@@ -914,6 +914,7 @@ _pnfs_return_layout(struct inode *ino)
 	lrp->args.stateid = stateid;
 	lrp->args.layout_type = NFS_SERVER(ino)->pnfs_curr_ld->id;
 	lrp->args.inode = ino;
+	lrp->args.iomode = IOMODE_ANY;
 	lrp->args.layout = lo;
 	lrp->clp = NFS_SERVER(ino)->nfs_client;
 	lrp->cred = lo->plh_lc_cred;

include/linux/nfs_xdr.h

@@ -293,6 +293,7 @@ struct nfs4_layoutreturn_args {
 	struct nfs4_sequence_args seq_args;
 	struct pnfs_layout_hdr *layout;
 	struct inode *inode;
+	enum pnfs_iomode iomode;
 	nfs4_stateid stateid;
 	__u32   layout_type;
 };