From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH 05/35 v3] libext2fs: add EXT4_INLINE_DATA_FL flag for inode Date: Mon, 16 Jul 2012 11:01:44 -0400 Message-ID: <20120716150144.GA3670@thunk.org> References: <1341150538-32047-1-git-send-email-wenqing.lz@taobao.com> <1341150538-32047-6-git-send-email-wenqing.lz@taobao.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org, Zheng Liu To: Zheng Liu Return-path: Received: from li9-11.members.linode.com ([67.18.176.11]:39304 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752617Ab2GPPBr (ORCPT ); Mon, 16 Jul 2012 11:01:47 -0400 Content-Disposition: inline In-Reply-To: <1341150538-32047-6-git-send-email-wenqing.lz@taobao.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sun, Jul 01, 2012 at 09:48:28PM +0800, Zheng Liu wrote: > From: Zheng Liu > > Add EXT4_INLINE_DATA_FL flag. > > /* EXT4_EOFBLOCKS_FL 0x00400000 was here */ > +#define EXT4_INLINE_DATA_FL 0x00800000 /* Inode has inline data */ Hi, Unfortunately, we have a codepoint collision. The BTRFS folks have already exposed FS_NOCOW_FL as 0x00800000; this is in mainline in the kernel, and in fact that latest version of e2fsprogs understands this since lsattr and chattr are used by multiple file systems (even though it was originally intended only for ext2/3/4). I'd like to move this to: #define EXT4_INLINE_DATA_FL 0x10000000 /* Inode has inline data */ However, if you already have this in production internally inside Taobao, this could potentially could be a problem for you. (We've had to handle this before inside Google, when we used a different code point for EOFBLOCKS_FL than what ended up being used in mainline; it can be dealt with, but it's certainly annoying...) Is this going to potentially be a problem for you? Regards, - Ted