From: Pavel Machek Subject: Re: [patch 1/1] Drop CAP_SYS_RAWIO requirement for FIBMAP Date: Mon, 29 Oct 2007 19:08:13 +0000 Message-ID: <20071029190813.GB7742@ucw.cz> References: <20071025230758.945535769@crlf.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel , Linux Kernel To: Mike Waychison Return-path: Received: from gprs189-60.eurotel.cz ([160.218.189.60]:4264 "EHLO spitz.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754573AbXKAOcz (ORCPT ); Thu, 1 Nov 2007 10:32:55 -0400 Content-Disposition: inline In-Reply-To: <20071025230758.945535769@crlf.corp.google.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Hi! > Remove the need for having CAP_SYS_RAWIO when doing a FIBMAP call on an open file descriptor. > > It would be nice to allow users to have permission to see where their data is landing on disk, and there really isn't a good reason to keep them from getting at this information. I believe it is to prevent users from intentionally creating extremely fragmented files... You can read 60MB in a second, but fragmented 60MB file could take 10msec * 60MB/4KB = 150 seconds. That's factor 150 slowdown... ...but I agree that SYS_RAWIO may be wrong capability to cover this. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html