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 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 9B427C433DB for ; Wed, 13 Jan 2021 14:43:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 55DC023136 for ; Wed, 13 Jan 2021 14:43:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726562AbhAMOnx (ORCPT ); Wed, 13 Jan 2021 09:43:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726471AbhAMOnx (ORCPT ); Wed, 13 Jan 2021 09:43:53 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5CABBC061575 for ; Wed, 13 Jan 2021 06:43:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=QNQINrc3aJBiPkPR6UycPtLSU1crJ5VdH0uN0ZQMfrw=; b=nLab75VE97AGOnf+SQxAzU2e2i 9ZIqox38UiMXnonNSwP7QoDmIF9h4gyfIR89CwNzCfB3Iovz+oCCcjmZUeCgHbeaiRF2W0i0OMu3r sNPgFcqGxIt1sh/8yD1bQjqlFB5kGIP89vuIiSDRtl0e3SO0201bI37XgDOWjS8yfyzduYjxITnl6 OKaJNWF4oeA/3DV5idGc4C0Nm0Unf4LtvVpdqixG2AaHq1j3xaaCqozkcwJLGnZbqPQhThsjDyqWR BtuAGIgG/xTER26ZOslE1FmVoKalCvC4rQTIOsqoKb/nJd16wFRK54d2gY0KZPg7EAG4SVQyCQ/rK 4TJIOGqQ==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1kzhJy-006N2k-5f; Wed, 13 Jan 2021 14:40:35 +0000 Date: Wed, 13 Jan 2021 14:40:26 +0000 From: "hch@infradead.org" To: Trond Myklebust Cc: "bfields@fieldses.org" , "hch@infradead.org" , "wangzhibei1999@gmail.com" , "security@kernel.org" , "w@1wt.eu" , "greg@kroah.com" , "linux-nfs@vger.kernel.org" , "pgoetz@math.utexas.edu" , "chuck.lever@oracle.com" Subject: Re: nfsd vurlerability submit Message-ID: <20210113144026.GA1517953@infradead.org> References: <20210108154230.GB950@1wt.eu> <20210111193655.GC2600@fieldses.org> <20210112153208.GF9248@fieldses.org> <8296b696a7fa5591ad3fbb05bfcf6bdf6175cc38.camel@hammerspace.com> <42fcbc42-f1b3-5d99-c507-e1b579f5a37a@math.utexas.edu> <20210112180326.GI9248@fieldses.org> <20210113081238.GA1428651@infradead.org> <0da3d3f1fee1a70eab3f78212f9282b03e21fc4d.camel@hammerspace.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <0da3d3f1fee1a70eab3f78212f9282b03e21fc4d.camel@hammerspace.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On Wed, Jan 13, 2021 at 02:34:45PM +0000, Trond Myklebust wrote: > On Wed, 2021-01-13 at 08:12 +0000, Christoph Hellwig wrote: > > FYI, if people really want to use some sort of subtree exports, for > > XFS > > (and probably ext4) we encode the project id into the file handle and > > use the hierarchical project ID inheritance that we already use for > > project quotas. > > You'd basically need something along the lines of a NetApp qtree. > > i.e. a persisted tag that can label all the files and directories in a > subtree, and that is used to enforce a set of rules that are generally > normally associated with filesystems. So no renames from objects inside > the subtree to directories that lie outside it. No hard links that > cross the subtree boundary. That is the XFS project ID, which ext4 has also picked up a few years ago.