NFS: Clean up NFS writeback flush code

The only user of nfs_sync_mapping_range() is nfs_getattr(), which uses it
to flush out the entire inode without sending a commit. We therefore
replace nfs_sync_mapping_range with a more appropriate helper.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 32bd5d3..15eec27 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -426,8 +426,8 @@
  * return value!)
  */
 extern long nfs_sync_mapping_wait(struct address_space *, struct writeback_control *, int);
-extern int nfs_sync_mapping_range(struct address_space *, loff_t, loff_t, int);
 extern int nfs_wb_all(struct inode *inode);
+extern int nfs_wb_nocommit(struct inode *inode);
 extern int nfs_wb_page(struct inode *inode, struct page* page);
 extern int nfs_wb_page_priority(struct inode *inode, struct page* page, int how);
 extern int nfs_wb_page_cancel(struct inode *inode, struct page* page);