Unionfs: support RT (real-time)

Signed-off-by: Paul Hewlett <paul@gccs.co.za>
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
diff --git a/fs/unionfs/super.c b/fs/unionfs/super.c
index beaa71a..ae5e409 100644
--- a/fs/unionfs/super.c
+++ b/fs/unionfs/super.c
@@ -82,7 +82,7 @@ static void unionfs_delete_inode(struct inode *inode)
 	spin_unlock(&inode->i_lock);
 #endif
 
-	if (inode->i_data.nrpages)
+       if (mapping_nrpages(&inode->i_data))
 		truncate_inode_pages(&inode->i_data, 0);
 
 	clear_inode(inode);