From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sukadev Bhattiprolu Subject: Re: Pagewriteback clarification Date: Wed, 28 Sep 2005 16:57:37 -0700 Message-ID: <20050928235736.GA26480@us.ibm.com> References: <20050928015738.GA12461@us.ibm.com> <17210.24512.240624.67693@gargle.gargle.HOWL> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org Return-path: Received: from e33.co.us.ibm.com ([32.97.110.151]:31879 "EHLO e33.co.us.ibm.com") by vger.kernel.org with ESMTP id S1751255AbVI1Xyx (ORCPT ); Wed, 28 Sep 2005 19:54:53 -0400 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e33.co.us.ibm.com (8.12.11/8.12.11) with ESMTP id j8SNrTvs032119 for ; Wed, 28 Sep 2005 19:53:29 -0400 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay04.boulder.ibm.com (8.12.10/NCO/VERS6.7) with ESMTP id j8SNtUct546728 for ; Wed, 28 Sep 2005 17:55:30 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11/8.13.3) with ESMTP id j8SNsqau014928 for ; Wed, 28 Sep 2005 17:54:52 -0600 To: Nikita Danilov Content-Disposition: inline In-Reply-To: <17210.24512.240624.67693@gargle.gargle.HOWL> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Thanks for your response. Yes I was referring to filesystems/Locking. | | No, callers of ->writepage() should assure that | | - page is locked, and | | - writeback bit is clear on that page. | | Which means that no IO is going on against this page. When | Documentation/filesystems/Locking talks about "currently-in-progress | I/O" it means any IO going to or fro the device, and "blocking against | in-progress I/O" means blocking due to device queue congestion. So is that referring to I/Os to/from the device from say pages other than the one in ->writepage(). I was guessing that the test_set_buffer_locked() in __block_write_full_page() is testing if I/O is in progress for a buffer belonging to this page. Is that not the case ?