From: tytso@mit.edu Subject: Re: [incomplete PATCH] ext4: avoid overflow in fiemap Date: Sat, 6 Mar 2010 22:38:18 -0500 Message-ID: <20100307033818.GA6241@thunk.org> References: <1267553925-6308-1-git-send-email-tytso@mit.edu> <1267553925-6308-12-git-send-email-tytso@mit.edu> <4B8E1410.1010107@rs.jp.nec.com> <20100303175217.GA3530@thunk.org> <4B8F47C6.9060408@rs.jp.nec.com> <1267739098.4204.12.camel@michlmayr> <1267741715.13886.4.camel@michlmayr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Akira Fujita , Ext4 Developers List To: Leonard Michlmayr Return-path: Received: from thunk.org ([69.25.196.29]:57126 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753501Ab0CGDiY (ORCPT ); Sat, 6 Mar 2010 22:38:24 -0500 Content-Disposition: inline In-Reply-To: <1267741715.13886.4.camel@michlmayr> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Mar 04, 2010 at 11:28:35PM +0100, Leonard Michlmayr wrote: > A __u32 cannot hold the maximum number of blocks in a file. This may > lead to an overflow if a fiemap request has length = s_maxbytes. > > I still get a segfault, I have to go through it again. This is just for > your information. I will work on it tomorrow. Check and see if it's still a problem with what I ultimately ended up pushing to Linus. Yes, the way I chose to fix things means that we'll never do more than 2**32-1 blocks at a time with fiemap, but in practice there's a limit to the number of extents that can be returned in a single fiemap call anyway, so in practice this shouldn't be a problem. - Ted