From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH] Ext4: remove a useless check for the function ext4_data_block_valid Date: Sun, 27 Jan 2013 07:38:31 -0500 Message-ID: <20130127123831.GC23996@thunk.org> References: <51045F77.5000106@gmail.com> <20130126153826.GB5887@thunk.org> <5105CA65.7020504@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: Wang Shilong Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:45692 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751247Ab3A0Mid (ORCPT ); Sun, 27 Jan 2013 07:38:33 -0500 Content-Disposition: inline In-Reply-To: <5105CA65.7020504@gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sun, Jan 27, 2013 at 04:46:29PM -0800, Wang Shilong wrote: > > Actually, it can be true --- if start_blk + count (which are both > > unsigned integers) overflows.... > Yeah,you are right.... > I am sorry,I miss the overflow condition... We added it because we saw a crash that was a caused by an overflow, if memory serves correctly. Or maybe it was a mysterious data or file system corruption that was incredibly painful to find. Fun trivia fact: the European Space Agency had the Ariane 5 rocket explode on its maiden flight due to a integer overflow bug. - Ted