Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946801AbXBJAXd (ORCPT ); Fri, 9 Feb 2007 19:23:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1946803AbXBJAXd (ORCPT ); Fri, 9 Feb 2007 19:23:33 -0500 Received: from wr-out-0506.google.com ([64.233.184.229]:45944 "EHLO wr-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946801AbXBJAXc (ORCPT ); Fri, 9 Feb 2007 19:23:32 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=nmho1zhHSjQv40eJFqtz6CWD+Xk2kadR7UIgXHamdanw2qtfcZ1PkyM7hv5D7nf5y39b7ECS9GmDYrLlqAc8DjL7gy64TQ9g7iVtX28bxKBJvUF86fcDAR48m9njV3UpF5ubgVA8JgznSIpEXTiYSDoDnB41UJvoKCM4qmb3ebw= Message-ID: Date: Fri, 9 Feb 2007 19:23:31 -0500 From: "Russ Cox" To: "Andrew Morton" Subject: Re: [PATCH] fix quadratic behavior of shrink_dcache_parent() Cc: "Miklos Szeredi" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20070209160055.bbd20c9f.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20070209160055.bbd20c9f.akpm@linux-foundation.org> X-Google-Sender-Auth: 8d365207a51bc89d Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 879 Lines: 24 > "The file system mounted on /tmp/z in the example contains 2^50 > directories". heh. > > I do wonder how realistic this problem is in real life. That's a fair concern, although I was trying this as part of evaluating how much someone could hose a system if we let them mount arbitrary FUSE servers. And the answer is: they could make it completely unusable, requiring reboot. I ran a later test that printed how deep it got into the file tree and it was only a few hundred thousand if I recall correctly. A determined attacker might even manage to do this in a normal file system. But sure, it's not a common case. ;-) Russ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/