From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 117DFC2B9F4 for ; Mon, 14 Jun 2021 22:50:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C9AA560D07 for ; Mon, 14 Jun 2021 22:50:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229760AbhFNWwq (ORCPT ); Mon, 14 Jun 2021 18:52:46 -0400 Received: from smtp-out1.suse.de ([195.135.220.28]:33764 "EHLO smtp-out1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229696AbhFNWwp (ORCPT ); Mon, 14 Jun 2021 18:52:45 -0400 Received: from imap.suse.de (imap-alt.suse-dmz.suse.de [192.168.254.47]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 6933721995; Mon, 14 Jun 2021 22:50:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1623711041; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=P4pTDeSF2y4uLXwHKaS8PMp4jCROv1FiN344ELVXeEk=; b=cujRGvD9RQW+gvPxcHckqEMU2SzYReDRQ5bnpcbC4FJmptM8Ni3RCeqIF92IxLrlvNpT9r wpplwaeZibHWg9BUx4fCSDQVaSTTV5sbct6MsnGyjcU9RVhrtUx6widgoGtAWzDo5y2Xjd 8TWBtYKPiGhUMjT7njvz3GyNMhiZdvw= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1623711041; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=P4pTDeSF2y4uLXwHKaS8PMp4jCROv1FiN344ELVXeEk=; b=kxIep/0dO0ojfGWdAeow9CuJTYda7GMWw9lvFQrkHyEckRFwv1hzE6gN35rxmTg3hn0VPW v0ecqIlz1Wx4uHAg== Received: from imap3-int (imap-alt.suse-dmz.suse.de [192.168.254.47]) by imap.suse.de (Postfix) with ESMTP id 249C3118DD; Mon, 14 Jun 2021 22:50:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1623711041; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=P4pTDeSF2y4uLXwHKaS8PMp4jCROv1FiN344ELVXeEk=; b=cujRGvD9RQW+gvPxcHckqEMU2SzYReDRQ5bnpcbC4FJmptM8Ni3RCeqIF92IxLrlvNpT9r wpplwaeZibHWg9BUx4fCSDQVaSTTV5sbct6MsnGyjcU9RVhrtUx6widgoGtAWzDo5y2Xjd 8TWBtYKPiGhUMjT7njvz3GyNMhiZdvw= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1623711041; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=P4pTDeSF2y4uLXwHKaS8PMp4jCROv1FiN344ELVXeEk=; b=kxIep/0dO0ojfGWdAeow9CuJTYda7GMWw9lvFQrkHyEckRFwv1hzE6gN35rxmTg3hn0VPW v0ecqIlz1Wx4uHAg== Received: from director2.suse.de ([192.168.254.72]) by imap3-int with ESMTPSA id OtxhMT7dx2DGbwAALh3uQQ (envelope-from ); Mon, 14 Jun 2021 22:50:38 +0000 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 From: "NeilBrown" To: "Wang Yugui" Cc: linux-nfs@vger.kernel.org Subject: Re: any idea about auto export multiple btrfs snapshots? In-reply-to: <20210613115313.BC59.409509F4@e16-tech.com> References: <20210613115313.BC59.409509F4@e16-tech.com> Date: Tue, 15 Jun 2021 08:50:35 +1000 Message-id: <162371103543.23575.13662722966178222587@noble.neil.brown.name> Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Sun, 13 Jun 2021, Wang Yugui wrote: > Hi, >=20 > Any idea about auto export multiple btrfs snapshots? >=20 > One related patch is yet not merged to nfs-utils 2.5.3. > From: "NeilBrown" > Subject: [PATCH/RFC v2 nfs-utils] Fix NFSv4 export of tmpfs filesystems. >=20 > In this patch, an UUID is auto generated when a tmpfs have no UUID. >=20 > for btrfs, multiple subvolume snapshot have the same filesystem UUID. > Could we generate an UUID for btrfs subvol with 'filesystem UUID' + 'subvol= ID'? You really need to ask this question of btrfs developers. 'mountd' already has a special-case exception for btrfs, to prefer the uuid provided by statfs64() rather than the uuid extracted from the block device. It would be quite easy to add another exception. But it would only be reasonable to do that if the btrfs team told us how that wanted us to generate a UUID for a given mount point, and promised that would always provide a unique stable result. This is completely separate from the tmpfs patch you identified. NeilBrown >=20 > Best Regards > Wang Yugui (wangyugui@e16-tech.com) > 2021/06/13 >=20 >=20 >=20