NFS: nfs_inode_return_delegation() should always flush dirty data

The assumption is that if you are in a situation where you need to
return the delegation, then you should probably stop caching the
data anyway.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/delegation.h b/fs/nfs/delegation.h
index cd6a7a8..72709c4 100644
--- a/fs/nfs/delegation.h
+++ b/fs/nfs/delegation.h
@@ -66,6 +66,7 @@
 
 static inline int nfs_inode_return_delegation(struct inode *inode)
 {
+	nfs_wb_all(inode);
 	return 0;
 }
 #endif