From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755578AbYICOet (ORCPT ); Wed, 3 Sep 2008 10:34:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752479AbYICOem (ORCPT ); Wed, 3 Sep 2008 10:34:42 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:50048 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752010AbYICOel (ORCPT ); Wed, 3 Sep 2008 10:34:41 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Tejun Heo Cc: Miklos Szeredi , serue@us.ibm.com, greg@kroah.com, fuse-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org References: <1219945263-21074-1-git-send-email-tj@kernel.org> <1219945263-21074-6-git-send-email-tj@kernel.org> <20080828175116.GB18461@kroah.com> <48B6E79E.6020702@kernel.org> <48B6E801.9080102@kernel.org> <48B6EBBD.6050406@kernel.org> <48B6EF98.4070008@kernel.org> <48B6FFB6.7000104@kernel.org> <48B75C94.7030604@kernel.org> <48B7AF60.8040709@kernel.org> <48B7BB4C.4060907@kernel.org> <48BBD9F5.8060906@kernel.org> Date: Wed, 03 Sep 2008 07:32:22 -0700 In-Reply-To: <48BBD9F5.8060906@kernel.org> (Tejun Heo's message of "Mon, 01 Sep 2008 14:03:01 +0200") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-XM-SPF: eid=;;;mid=;;;hst=mx04.mta.xmission.com;;;ip=24.130.11.59;;;frm=ebiederm@xmission.com;;;spf=neutral X-SA-Exim-Connect-IP: 24.130.11.59 X-SA-Exim-Rcpt-To: too long (recipient list exceeded maximum allowed size of 128 bytes) X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-DCC: XMission; sa03 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Tejun Heo X-Spam-Relay-Country: X-Spam-Report: * -1.8 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -0.7 BAYES_20 BODY: Bayesian spam probability is 5 to 20% * [score: 0.0962] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa03 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 XM_SPF_Neutral SPF-Neutral Subject: Re: [PATCH 5/7] FUSE: implement ioctl support X-SA-Exim-Version: 4.2.1 (built Thu, 07 Dec 2006 04:40:56 +0000) X-SA-Exim-Scanned: Yes (on mx04.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tejun Heo writes: > Hello, > > Miklos Szeredi wrote: >>> So why not just only support well defined ioctls and serialize them >>> in the kernel and allow the receiving process to deserialize them? >> >> I'd like the idea of limiting to well behaved ioctls, but Tejun >> doesn't... > > I'm not dead against it. I'm just a bit more inclined to my > implementation (naturally), which means if you're dead against the > current implementation, supporting only the proper ones definitely is > an option, but comparing the pros and cons, I'm not quite convinced > yet. I really think that if an ioctl is passing through the kernel we should know how to parse and understand it's options. Otherwise we won't have the option of doing backwards compatibility when something changes, like we can with the 32->64bit ioctls. That seems to imply that you need a stub in the kernel to handle really weird ioctls. The upside is that because you know what the inputs and outputs are and where the inputs and output are you can support that ioctl well into the future, and you can do it with an unprivileged file system server. Eric