From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Paris Subject: Re: [PATCH 0/4] IMA: making i_readcount a first class inode citizen Date: Thu, 28 Oct 2010 18:45:07 -0400 Message-ID: <1288305907.3017.1.camel@localhost.localdomain> References: <1288303325-9628-1-git-send-email-zohar@linux.vnet.ibm.com> <20101028222404.GG2715@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Dave Chinner , Mimi Zohar , linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, hch@infradead.org, warthog9@kernel.org, jmorris@namei.org, kyle@mcmartin.ca, hpa@zytor.com, akpm@linux-foundation.org, mingo@elte.hu, viro@zeniv.linux.org.uk, Matthew Wilcox To: Linus Torvalds Return-path: Received: from mx1.redhat.com ([209.132.183.28]:37074 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753305Ab0J1WqO (ORCPT ); Thu, 28 Oct 2010 18:46:14 -0400 In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Thu, 2010-10-28 at 15:29 -0700, Linus Torvalds wrote: > On Thu, Oct 28, 2010 at 3:24 PM, Dave Chinner wrote: > > > > Why the wrapper functions and locking? Why not an atomic variable like > > i_writecount? > > Indeed. With moving this more into the VFS, let's just make sure it > looks like i_writecount as much as possible. My thought was that the IMA read/write checks should happen AFTER the i_writecount and i_readcount counters were updated. Thus even if we raced with another task we can rest assured that the other task would catch the situation we missed.... -Eric