NFSv4.1: filelayout read

Attempt a pNFS file layout read by setting up the nfs_read_data struct and
calling nfs_initiate_read with the data server rpc client and the
filelayout rpc call ops.

Error handling is implemented in a subsequent patch.

Signed-off-by: Andy Adamson <andros@citi.umich.edu>
Signed-off-by: Dean Hildebrand <dhildeb@us.ibm.com>
Signed-off-by: Fred Isaman <iisaman@citi.umich.edu>
Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Mingyang Guo <guomingyang@nrchpc.ac.cn>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Tested-by: Guo Mingyang <guomingyang@nrchpc.ac.cn>
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 4127a1c0..f4d0fcf 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -157,7 +157,7 @@
 	nfs_release_request(req);
 }
 
-static int nfs_initiate_read(struct nfs_read_data *data, struct rpc_clnt *clnt,
+int nfs_initiate_read(struct nfs_read_data *data, struct rpc_clnt *clnt,
 		      const struct rpc_call_ops *call_ops)
 {
 	struct inode *inode = data->inode;
@@ -195,6 +195,7 @@
 	rpc_put_task(task);
 	return 0;
 }
+EXPORT_SYMBOL_GPL(nfs_initiate_read);
 
 /*
  * Set up the NFS read request struct