From: Eric Sandeen Subject: Re: [PATCH] Fix EXT4_FEATURE_RO_COMPAT_HUGE_FILE check Date: Tue, 24 Aug 2010 11:41:11 -0500 Message-ID: <4C73F627.2000809@redhat.com> References: <4c7325f6.02558f0a.5a24.ffffc694@mx.google.com> <426FFD16-98B3-4427-BDA5-C80CE184781C@dilger.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Justin Maggard , linux-ext4@vger.kernel.org To: Andreas Dilger Return-path: Received: from mx1.redhat.com ([209.132.183.28]:6260 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754343Ab0HXQlQ (ORCPT ); Tue, 24 Aug 2010 12:41:16 -0400 In-Reply-To: <426FFD16-98B3-4427-BDA5-C80CE184781C@dilger.ca> Sender: linux-ext4-owner@vger.kernel.org List-ID: Andreas Dilger wrote: > This isn't the first time that we've had problems like this, and it > won't be the last time unless there is a better API for checking > these flags. *nod* > I've long thought about having something like: Same thing crossed my mind; seems like a very good idea. > #define EXT4_CHECK_COMPAT(sb, flag) ((super)->s_feature_compat & \ > EXT4_FEATURE_COMPAT_ ## flag) > #define EXT4_CHECK_RO_COMPAT(sb, flag) ((super)->s_feature_ro_compat & \ > EXT4_FEATURE_RO_COMPAT_ ## flag) > #define EXT4_CHECK_INCOMPAT(sb, flag) ((super)->s_feature_incompat & \ > EXT4_FEATURE_INCOMPAT_ ## flag) > #define EXT4_SET_COMPAT(sb, flag) do { (super)->s_feature_compat |= \ > EXT4_FEATURE_COMPAT_ ## flag; } while(0) > #define EXT4_SET_RO_COMPAT(sb, flag) do { (super)->s_feature_ro_compat |= \ > EXT4_FEATURE_RO_COMPAT_ ##flag;} while(0) > #define EXT4_SET_INCOMPAT(sb, flag) do { (super)->s_feature_incompat |= \ > EXT4_FEATURE_INCOMPAT_ ## flag;} while(0) > > This will produce a compile error if the flag name and the macro name > don't match. Unfortunately, for e2fsprogs we will need 3 sets of such > macros because the feature flags are named EXT2_*, EXT3_*, and > EXT4_*, depending on when they were added. For the kernel code that > wouldn't be needed. Time to name them consistently in e2fsprogs, then, I think? -Eric > Cheers, Andreas