From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH v1 5/10] ext4: Add DX_HASH_SIPHASH24 support Date: Tue, 23 Sep 2014 21:47:44 -0400 Message-ID: <20140924014744.GJ17784@thunk.org> References: <0765A511-D5E2-4F00-8F2F-F5A8E76C0B03@dilger.ca> <20140923204527.20932.qmail@ns.horizon.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: adilger@dilger.ca, linux-ext4@vger.kernel.org To: George Spelvin Return-path: Received: from imap.thunk.org ([74.207.234.97]:44650 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752857AbaIXBru (ORCPT ); Tue, 23 Sep 2014 21:47:50 -0400 Content-Disposition: inline In-Reply-To: <20140923204527.20932.qmail@ns.horizon.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Sep 23, 2014 at 04:45:27PM -0400, George Spelvin wrote: > > Er... I'll let Ted tell me if I screwed up, but I went through > the code quite carefully figuring out what value to use, and > DX_HASH_LEGACY_UNSIGNED is *not* an on-disk encoding. You're right, but it would probably be safer to have a hole in the on-disk numbering. That's because changing the numbering of EXT2_HASH_*_UNSIGNED will change the ABI of ext2fs_dirhash(). While we don't officially support a mismatch between the version of e2fsck and libext2fs, and it's unlikely that other programs would be trying to use ext2fs_dirhash. Still, it would probably simpler to not try to assign DX_HASH_SIPHASH24 to be 6, and to leave better comments about how the hash values are used. Cheers, - Ted