From: Valerie Aurora Subject: Re: [PATCH 15/41] whiteout: ext2 whiteout support Date: Mon, 26 Oct 2009 22:14:26 -0400 Message-ID: <20091027021426.GA14574@shell> References: <1256152779-10054-8-git-send-email-vaurora@redhat.com> <1256152779-10054-9-git-send-email-vaurora@redhat.com> <1256152779-10054-10-git-send-email-vaurora@redhat.com> <1256152779-10054-11-git-send-email-vaurora@redhat.com> <1256152779-10054-12-git-send-email-vaurora@redhat.com> <1256152779-10054-13-git-send-email-vaurora@redhat.com> <1256152779-10054-14-git-send-email-vaurora@redhat.com> <1256152779-10054-15-git-send-email-vaurora@redhat.com> <1256152779-10054-16-git-send-email-vaurora@redhat.com> <1983FB3A-C88F-4EF4-A2E1-8B18DF97F0AB@sun.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Blunck , Alexander Viro , Christoph Hellwig , Andy Whitcroft , Scott James Remnant , Sandu Popa Marius , Jan Rekorajski , "J. R. Okajima" , Arnd Bergmann , Vladimir Dronnikov , Felix Fietkau , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Theodore Tso , linux-ext4@vger.kernel.org To: Andreas Dilger Return-path: Received: from mx1.redhat.com ([209.132.183.28]:51316 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752889AbZJ0CPA (ORCPT ); Mon, 26 Oct 2009 22:15:00 -0400 Content-Disposition: inline In-Reply-To: <1983FB3A-C88F-4EF4-A2E1-8B18DF97F0AB@sun.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Oct 21, 2009 at 03:17:38PM -0600, Andreas Dilger wrote: > On 2009-10-21, at 13:19, Valerie Aurora wrote: > >This patch adds whiteout support to EXT2. A whiteout is an empty > >directory > >entry (inode == 0) with the file type set to EXT2_FT_WHT. Therefore it > >allocates space in directories. Due to being implemented as a > >filetype it is > >necessary to have the EXT2_FEATURE_INCOMPAT_FILETYPE flag set. > > > >diff --git a/include/linux/ext2_fs.h b/include/linux/ext2_fs.h > >index 121720d..bd10826 100644 > >--- a/include/linux/ext2_fs.h > >+++ b/include/linux/ext2_fs.h > >@@ -189,6 +189,7 @@ struct ext2_group_desc > >+#define EXT2_OPAQUE_FL 0x00040000 > > Please check in the upstream e2fsprogs ext2_fs.h before defining new > flag > values for ext2/3/4. In this case, 0x40000 conflicts with > EXT4_HUGE_FILE_FL, > which is of course bad. > > > >@@ -503,10 +504,12 @@ struct ext2_super_block { > >#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010 > >+#define EXT2_FEATURE_INCOMPAT_WHITEOUT 0x0020 > > This one doesn't conflict, probably due to luck, because 0x0040-0x0200 > are > already in use for other features. I'm not sure if 0x0020 was > reserved for > some other use, or just skipped to avoid potential conflicts. Thanks for reviewing! I'll fix that in the next rev. -VAL