From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mgwkm02.jp.fujitsu.com ([202.219.69.169]:62852 "EHLO mgwkm02.jp.fujitsu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751395AbeCWIOW (ORCPT ); Fri, 23 Mar 2018 04:14:22 -0400 Received: from g01jpfmpwkw03.exch.g01.fujitsu.local (g01jpfmpwkw03.exch.g01.fujitsu.local [10.0.193.57]) by kw-mxq.gw.nic.fujitsu.com (Postfix) with ESMTP id 1BE04AC0142 for ; Fri, 23 Mar 2018 17:14:16 +0900 (JST) Subject: Re: [PATCH] btrfs-progs: mkfs: add uuid and otime to ROOT_ITEM of FS_TREE To: , linux-btrfs References: <7ca269db-a724-5938-f4d8-b85e893fd558@jp.fujitsu.com> <20180321174838.GW6955@twin.jikos.cz> From: Misono Tomohiro Message-ID: Date: Fri, 23 Mar 2018 17:14:10 +0900 MIME-Version: 1.0 In-Reply-To: <20180321174838.GW6955@twin.jikos.cz> Content-Type: text/plain; charset="utf-8" Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 2018/03/22 2:48, David Sterba wrote: > On Mon, Mar 19, 2018 at 05:16:42PM +0900, Misono, Tomohiro wrote: >> Currently, the top-level subvolume lacks the UUID. As a result, both >> non-snapshot subvolume and snapshot of top-level subvolume do not have >> Parent UUID and cannot be distinguisued. Therefore "fi show" of >> top-level lists all the subvolumes which lacks the UUID in >> "Snapshot(s)" filed. Also, it lacks the otime information. >> >> Fix this by adding the UUID and otime at the mkfs time. As a >> consequence, snapshots of top-level subvolume now have a Parent UUID and >> UUID tree will create an entry for top-level subvolume at mount time. >> This should not cause the problem for current kernel, but user program >> which relies on the empty Parent UUID may be affected by this change. >> >> Signed-off-by: Tomohiro Misono > > So this adds uuid, ctime and otime to FS_TEEE but also to UUID_TREE and > DATA_RELOC_TREE. This is harmelss, but would be nice to mention in the > changelog, I'll apply the patch add that. Thanks. UUID is cleared at create_tree(), so I think you mean otime and ctime. However, other tree's ROOT_ITEM does not hold o/ctime and I'd like to clear o/ctime for UUID/DATA_RELOC_TREE too. So, I will send v2 patch and could you please use that instead of this? Regards, Tomohiro Misono