From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [RFC Aufs2 #2 21/28] aufs sysfs entries Date: Mon, 16 Mar 2009 20:37:47 -0700 Message-ID: <20090317033747.GA17037@kroah.com> References: <1237188040-11404-1-git-send-email-hooanon05@yahoo.co.jp> <1237188040-11404-22-git-send-email-hooanon05@yahoo.co.jp> <20090316180538.GA7069@kroah.com> <7200.1237260402@jrobl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org To: hooanon05@yahoo.co.jp Return-path: Received: from kroah.org ([198.145.64.141]:34995 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751214AbZCQDjN (ORCPT ); Mon, 16 Mar 2009 23:39:13 -0400 Content-Disposition: inline In-Reply-To: <7200.1237260402@jrobl> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, Mar 17, 2009 at 12:26:42PM +0900, hooanon05@yahoo.co.jp wrote: > > Thank you very much for reviewing. > > Greg KH: > > > +/* todo: file size may exceed PAGE_SIZE */ > > > +ssize_t sysaufs_si_show(struct kobject *kobj, struct attribute *attr, > > > + char *buf) > > > > NO IT CAN NOT!!!! > > > > You are using sysfs wrong if you even think you are getting close to > > PAGE_SIZE. > > The main reason I left a comment about PAGE_SIZE is that some of aufs > entry under sysfs contain the file path. Which should be MAX_PATH, right? Is that ever bigger than PAGE_SIZE? > And I don't think it is a good idea to create a symlink since the path > may be changed as a result of users operation. > I left it as "todo" because such long path is rare. > > If you have an idea to show users any file path which may be changed > dynamically, please let me know. At the beginning I have tried procfs, > but I was told that newer module should use sysfs instead of procfs. If > sysfs doesn't suit a path, what should I use? Debugfs? What specifically are you trying to show here? > > Please, use debugfs for this. sysfs is a "one value per file" type > > filesystem. You should never be using the seqfile interface for a sysfs > > file, that's a sure sign something is wrong in your design. > > > > I think I'll stop reading now :( > > I will change some entries which doesn't contain a file path (or make > them not to have have) and post again. So please don't stop reading. Please document your sysfs entries, and I'll be glad to review it again. thanks, greg k-h