NFS: Create an write_pageio_init() function

pNFS needs to select a write function based on the layout driver
currently in use, so I let each NFS version decide how to best handle
initializing writes.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/pnfs.h b/fs/nfs/pnfs.h
index 80ee891..592beb0 100644
--- a/fs/nfs/pnfs.h
+++ b/fs/nfs/pnfs.h
@@ -180,7 +180,7 @@
 
 void pnfs_pageio_init_read(struct nfs_pageio_descriptor *, struct inode *,
 			   const struct nfs_pgio_completion_ops *);
-bool pnfs_pageio_init_write(struct nfs_pageio_descriptor *, struct inode *,
+void pnfs_pageio_init_write(struct nfs_pageio_descriptor *, struct inode *,
 			    int, const struct nfs_pgio_completion_ops *);
 
 void set_pnfs_layoutdriver(struct nfs_server *, const struct nfs_fh *, u32);
@@ -444,10 +444,10 @@
 	nfs_pageio_init_read(pgio, inode, compl_ops);
 }
 
-static inline bool pnfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *inode, int ioflags,
+static inline void pnfs_pageio_init_write(struct nfs_pageio_descriptor *pgio, struct inode *inode, int ioflags,
 					  const struct nfs_pgio_completion_ops *compl_ops)
 {
-	return false;
+	nfs_pageio_init_write(pgio, inode, ioflags, compl_ops);
 }
 
 static inline int