From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 19 Apr 2002 00:38:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 19 Apr 2002 00:38:17 -0400 Received: from holomorphy.com ([66.224.33.161]:22944 "EHLO holomorphy") by vger.kernel.org with ESMTP id ; Fri, 19 Apr 2002 00:38:16 -0400 Date: Thu, 18 Apr 2002 21:37:29 -0700 From: William Lee Irwin III To: linux-kernel@vger.kernel.org Cc: viro@math.psu.edu Subject: Re: [RFC] 2.4 truncate locking Message-ID: <20020419043729.GZ21206@holomorphy.com> Mail-Followup-To: William Lee Irwin III , linux-kernel@vger.kernel.org, viro@math.psu.edu In-Reply-To: <20020417150912.GI23767@holomorphy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Description: brief message Content-Disposition: inline User-Agent: Mutt/1.3.25i Organization: The Domain of Holomorphy Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 17, 2002 at 08:09:12AM -0700, William Lee Irwin III wrote: > I did some research on how truncate_inode_pages()'s locking works. > Please feel free to clarify and/or correct my notes on the subject, > which I'd like to turn into a docpatch soon. > > (9) exclusion from simultaneous manipulation of page->mapping > pagemap_lru_lock This is incorrect. It appears to be a combination of PG_locked and pagecache_lock, where both are required for writing, and only one of the two for reading. Cheers, Bill