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[2620:137:e000::1:20]) by mx.google.com with ESMTP id l20-20020a056a0016d400b005739d652ab4si12473095pfc.286.2022.11.28.03.58.46; Mon, 28 Nov 2022 03:59:06 -0800 (PST) Received-SPF: pass (google.com: domain of linux-nfs-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=k20201202 header.b=E18jd0Hf; spf=pass (google.com: domain of linux-nfs-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-nfs-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231298AbiK1Ltw (ORCPT + 99 others); Mon, 28 Nov 2022 06:49:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56274 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231261AbiK1Ltr (ORCPT ); Mon, 28 Nov 2022 06:49:47 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8715A17E26; Mon, 28 Nov 2022 03:49:41 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 3385BB80D63; Mon, 28 Nov 2022 11:49:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ABD20C433C1; Mon, 28 Nov 2022 11:49:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669636178; bh=nUD6wWWFNxtPNb8m2y9VRRA9H42MmowlBVJDxx/RGsE=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=E18jd0HflNEVZ2ajShDHJJIkNA7E1IMhsfwD6zt+nnk/NTjZ2PMgO045Q58aVDBG1 uALGlHvnNiBnfY2x6LcAwG8ge6e8nRo1MwLr5AVv9XbYuSyeylEiXRnfeb8nY60w5P ONLqwxmOpb/ykHrj+Xv7KSbSrFkvNvLSNOC1oK/bqRF6I3iGE41jkrXS5L2Y6PWfEE N1hVuh9fPwygFYJgT/RnquEf0vlW3MluQpzLXeSfrcGFwLitmKf+EYhti3I/xrrZ7Y ZnVhWk9heRFqfpVir+FWvoRUcn7LaMxvx+DPgmBBzee8LLmvTeX1hE4kZtsjVGj+60 b5jwKV6k8w+kQ== Message-ID: <8ca382fa391a08313ba8dc5ce115e1832e32aebb.camel@kernel.org> Subject: Re: [PATCH 2/3] fs: namei: Allow follow_down() to uncover auto mounts From: Jeff Layton To: Richard Weinberger Cc: linux-nfs , linux-kernel , linux-fsdevel , chuck lever , anna , trond myklebust , Al Viro , raven , chris chilvers , david young , luis turcitu , david Date: Mon, 28 Nov 2022 06:49:36 -0500 In-Reply-To: <1045320558.283423.1669584585412.JavaMail.zimbra@nod.at> References: <20221117191151.14262-1-richard@nod.at> <20221117191151.14262-3-richard@nod.at> <1805608101.252119.1668719538854.JavaMail.zimbra@nod.at> <29d007755c6066552ac2a1b5bc498ce1ce28ab3b.camel@kernel.org> <1045320558.283423.1669584585412.JavaMail.zimbra@nod.at> Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.46.1 (3.46.1-1.fc37) MIME-Version: 1.0 X-Spam-Status: No, score=-7.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Sun, 2022-11-27 at 22:29 +0100, Richard Weinberger wrote: > ----- Urspr=FCngliche Mail ----- > > Von: "Jeff Layton" > > > So, in nfsd_cross_mnt() the follow_down() helper should use LOOKUP_AU= TOMOUNT > > > only > > > if exp->ex_flags & NFSEXP_CROSSMOUNT is true? > > > Sounds sane, thanks for the pointer. > > >=20 > >=20 > > Yeah, I think so. I do wonder if we ought to make any provision for > > "nohide" exports, but since you have to enumerate those explicitly, it > > shouldn't be a huge problem for someone to just ensure that they're > > mounted beforehand. >=20 > TBH, I didn't invest much into the nohide feature wrt. NFS re-exporting. > What problem do you have in mind? >=20 nohide is sort of complimentary to crossmnt. You can achieve the same effect as crossmnt by adding explicit exports for all the children and marking them "nohide". The point here is that you have to explicitly create exports for the child mounts in that case, and if you're doing that then it's not a burden for the admin to make sure they're mounted before exporting. So, I don't think we need to worry about nohide here after all. > I wonder also what NFS client folks think about my changes before I send > the next revision (with Jeff's comments addressed). --=20 Jeff Layton