Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751375AbWHRX5G (ORCPT ); Fri, 18 Aug 2006 19:57:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751592AbWHRX5G (ORCPT ); Fri, 18 Aug 2006 19:57:06 -0400 Received: from mx1.redhat.com ([66.187.233.31]:39641 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S1751375AbWHRX5F (ORCPT ); Fri, 18 Aug 2006 19:57:05 -0400 Message-ID: <44E653CA.1060502@redhat.com> Date: Fri, 18 Aug 2006 18:56:58 -0500 From: Eric Sandeen User-Agent: Thunderbird 1.5.0.5 (Macintosh/20060719) MIME-Version: 1.0 To: Eric Sandeen , Mingming Cao , sho@tnes.nec.co.jp, ext2-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [Ext2-devel] [PATCH] fix ext3 mounts at 16T References: <20060818181516sho@rifu.tnes.nec.co.jp> <44E5F9F0.6030805@us.ibm.com> <44E5FB5D.60403@redhat.com> <20060818231855.GW6634@schatzie.adilger.int> In-Reply-To: <20060818231855.GW6634@schatzie.adilger.int> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1711 Lines: 37 Andreas Dilger wrote: > On Aug 18, 2006 12:39 -0500, Eric Sandeen wrote: >> @@ -168,7 +168,7 @@ goal_in_my_reservation(struct ext3_reser >> ext3_fsblk_t group_first_block, group_last_block; >> >> group_first_block = ext3_group_first_block_no(sb, group); >> - group_last_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1; >> + group_last_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1); >> >> if ((rsv->_rsv_start > group_last_block) || >> (rsv->_rsv_end < group_first_block)) >> @@ -897,7 +897,7 @@ static int alloc_new_reservation(struct >> spinlock_t *rsv_lock = &EXT3_SB(sb)->s_rsv_window_lock; >> >> group_first_block = ext3_group_first_block_no(sb, group); >> - group_end_block = group_first_block + EXT3_BLOCKS_PER_GROUP(sb) - 1; >> + group_end_block = group_first_block + (EXT3_BLOCKS_PER_GROUP(sb) - 1); >> >> if (grp_goal < 0) >> start_block = group_first_block; > > I don't see how these can make a difference? Surely, if the intermediate > sum overflows it will then underflow when "- 1" is done? Not that I mind, > per-se, just curious why you think this fixes anything. Well, you're right, if it overflows then it will underflow again. And I've not observed any actual failures, and I don't expect to. But personally I guess I'd rather avoid the whole overflow in the first place... maybe I'm being silly. :) If you think it's unnecessary code churn then we can not make this change... -Eric - 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/