From: Nathan Scott Subject: Re: [RFC][PATCH] Secure Deletion and Trash-Bin Support for Ext4 Date: Thu, 07 Dec 2006 09:16:31 +1100 Message-ID: <1165443391.1281.135.camel@edge> References: <20061204235042.GS33919298@melbourne.sgi.com> <20061206091100.GA33919298@melbourne.sgi.com> Reply-To: nscott@aconex.com Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Nikolai Joukov , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, xfs@oss.sgi.com Return-path: Received: from mail.app.aconex.com ([203.89.192.138]:36763 "EHLO mail.aconex.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S968688AbWLGDz7 (ORCPT ); Wed, 6 Dec 2006 22:55:59 -0500 To: David Chinner In-Reply-To: <20061206091100.GA33919298@melbourne.sgi.com> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Wed, 2006-12-06 at 20:11 +1100, David Chinner wrote: > ... > If all we need to add to XFS is support for those flags, then XFS > support would be trivial to add. > > Oh, damn. I take that back. We're almost out of flag space in the on > disk inode - these two flags would use the last 2 flag bits so this > may require an on disk inode format change in XFS. This will be > a little more complex than I first thought, ... It should be OK - you can do it without an inode version revision if you take a second 16 bits for "di_flags2" from here... xfs_dinode_core { ... __uint8_t di_pad[8]; /* unused, zeroed space */ Its guaranteed zeroed initially (i.e. all flags unset) and the XFS get/set flags APIs are 32 bits, so you should be OK there. Also, it may also be possible to reclaim di_onlink at some point (maybe now, since 16 bits would be good here) if mkfs.xfs is changed to always create v2 inodes (dynamic conversion ATM IIRC)... not 100% sure though, needs more code analysis. cheers. -- Nathan