Return-Path: Received: from mail-out2.uio.no ([129.240.10.58]:37504 "EHLO mail-out2.uio.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758796Ab0KRP1r (ORCPT ); Thu, 18 Nov 2010 10:27:47 -0500 Subject: Re: Question about nfs_page_async_flush assertion From: Trond Myklebust To: Peng Tao Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Date: Thu, 18 Nov 2010 10:27:43 -0500 Message-ID: <1290094063.3187.41.camel@heimdal.trondhjem.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Thu, 2010-11-18 at 18:53 +0800, Peng Tao wrote: > Hi, all, > > nfs_writepages calls into > write_cache_pages()->nfs_writepages_callback()->nfs_do_writepage()->nfs_page_async_flush(), > where it asserts BUG_ON(test_bit(PG_CLEAN, &req->wb_flags)). > My question is: how do we guarantee the request has PG_CLEAN flag set? We don't. We guarantee that the request has PG_CLEAN cleared, and that is done when we dirty the page (see nfs_try_to_update_request()). Cheers Trond