NFS: Create custom NFS v4 write_inode() function

This gives pnfs a chance to do a layout commit inside the v4 code.

Signed-off-by: Bryan Schumaker <bjschuma@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index c11fb00..f312860 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1671,9 +1671,14 @@
 
 int nfs_write_inode(struct inode *inode, struct writeback_control *wbc)
 {
-	int ret;
+	return nfs_commit_unstable_pages(inode, wbc);
+}
 
-	ret = nfs_commit_unstable_pages(inode, wbc);
+#ifdef CONFIG_NFS_V4
+int nfs4_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	int ret = nfs_write_inode(inode, wbc);
+
 	if (ret >= 0 && test_bit(NFS_INO_LAYOUTCOMMIT, &NFS_I(inode)->flags)) {
 		int status;
 		bool sync = true;
@@ -1687,6 +1692,7 @@
 	}
 	return ret;
 }
+#endif
 
 /*
  * flush the inode to disk.