From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id 1CDD26B0069 for ; Mon, 7 Nov 2011 09:28:00 -0500 (EST) Received: by ywa17 with SMTP id 17so6955115ywa.14 for ; Mon, 07 Nov 2011 06:27:57 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20111107135823.3a7cdc53@lxorguk.ukuu.org.uk> References: <1320614101.3226.5.camel@offbook> <20111107112952.GB25130@tango.0pointer.de> <1320675607.2330.0.camel@offworld> <20111107135823.3a7cdc53@lxorguk.ukuu.org.uk> From: Kay Sievers Date: Mon, 7 Nov 2011 15:27:36 +0100 Message-ID: Subject: Re: [RFC PATCH] tmpfs: support user quotas Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Alan Cox Cc: Davidlohr Bueso , Lennart Poettering , Christoph Hellwig , Hugh Dickins , Andrew Morton , lkml , linux-mm@kvack.org On Mon, Nov 7, 2011 at 14:58, Alan Cox wrote: >> Right, rlimit approach guarantees a simple way of dealing with users >> across all tmpfs instances. > > Which is almost certainly not what you want to happen. Think about direct > rendering. > > For simple stuff tmpfs already supports size/nr_blocks/nr_inodes mount > options so you can mount private resource constrained tmpfs objects > already without kernel changes. No rlimit hacks needed - and rlimit is > the wrong API anyway. What part of the message did you read? This is about _per_user_ limits, not global limits! Any untrusted user can fill /dev/shm today and DOS many services that way on any machine out there. Same for /tmp when it's a tmpfs, or /run/user. This is an absolutely unacceptable state and needs fixing. I don't care about which interface it is, if someting else fits better, let's discuss that, but it has surely absolutely noting to do with size/nr_blocks/nr_inodes. Kay -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org