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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 1BF79C4338F for ; Fri, 6 Aug 2021 08:26:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F3F47606A5 for ; Fri, 6 Aug 2021 08:26:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244468AbhHFI0g (ORCPT ); Fri, 6 Aug 2021 04:26:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244794AbhHFIZ4 (ORCPT ); Fri, 6 Aug 2021 04:25:56 -0400 Received: from mail-ua1-x92b.google.com (mail-ua1-x92b.google.com [IPv6:2607:f8b0:4864:20::92b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 14BD0C06179C for ; Fri, 6 Aug 2021 01:18:31 -0700 (PDT) Received: by mail-ua1-x92b.google.com with SMTP id t26so3269129uao.12 for ; Fri, 06 Aug 2021 01:18:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=szeredi.hu; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=oRINHIhGfpdECjbAWjxe8NCFfhDC/n86ssJULKDPhmA=; b=OvVgEpKzEDMU8cgihSAEKuEjP5IfZ8rbtWlFLdngFqtrTL5fK1CX0NS4xQj++RKSVB yVez7hdiedBIpuLGnZoKY5PPD4mryOnVQh31czsX1KY5p84kn/zeyXojCmSM2Dkqw1jz xAZyFZz7o/659lHhsG5JSIw1m3Pz+HLGSd6kw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=oRINHIhGfpdECjbAWjxe8NCFfhDC/n86ssJULKDPhmA=; b=eF8voRRmRIIGN4BLMIx/8bGhlaHD+KlaKVG5AqUKK+FiHTWaGew5I5kcqclLFKfsKh 6hoz/h3QZd6O8kRwaajl8awqXSjii59heFKlnKDeaSTre8PbFEY4YbfEUUWKPy/jKuNu 7pQIUFugnR2W93NJYg2P/k++RUoLC0mWWsK/K6OC4PoAyfZS6nCzEyZvUHNQzZ0bvoFN MggmwO9C1vY3G6vkuEYiWxPLq0A3OCOJsRuxVYsICRFX7BjVveBFPO4HONHKnDM/9VQG eDSdHD7t+bCPnGwkDJLg7f+nbU85W1IWjWUdmH5PG+uxwaG8uK5oOpd3Mf+lw0RQ5gOy 1eYA== X-Gm-Message-State: AOAM533qAgdMsEOtZu0PbYG+GADPNHHXscBtcEq5bdWmYtlh+POl3O+s oPPgef9HYSGKIEBNJ47EEaoRV8azxavcPHyF3woFFg== X-Google-Smtp-Source: ABdhPJwNHoJAQK2vyoS6CI4mikJ6sKLtxvgwY+3QqhxnrCcHZcmZAhSUiHUKQcB0A6vLxde6qR99BdAABMh7bTKc0/A= X-Received: by 2002:ab0:36af:: with SMTP id v15mr7156096uat.8.1628237910214; Fri, 06 Aug 2021 01:18:30 -0700 (PDT) MIME-Version: 1.0 References: <162742539595.32498.13687924366155737575.stgit@noble.brown> <162742546554.32498.9309110546560807513.stgit@noble.brown> <162751852209.21659.13294658501847453542@noble.neil.brown.name> In-Reply-To: From: Miklos Szeredi Date: Fri, 6 Aug 2021 10:18:19 +0200 Message-ID: Subject: Re: [PATCH 07/11] exportfs: Allow filehandle lookup to cross internal mount points. To: Amir Goldstein Cc: NeilBrown , Christoph Hellwig , Josef Bacik , "J. Bruce Fields" , Chuck Lever , Chris Mason , David Sterba , Alexander Viro , linux-fsdevel , Linux NFS Mailing List , Linux Btrfs Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Fri, 6 Aug 2021 at 10:08, Amir Goldstein wrote: > > On Fri, Aug 6, 2021 at 10:52 AM Miklos Szeredi wrote: > > > > On Thu, 29 Jul 2021 at 07:27, Amir Goldstein wrote: > > > > > Given that today, subvolume mounts (or any mounts) on the lower layer > > > are not followed by overlayfs, I don't really see the difference > > > if mounts are created manually or automatically. > > > Miklos? > > > > Never tried overlay on btrfs. Subvolumes AFAIK do not use submounts > > currently, they are a sort of hack where the st_dev changes when > > crossing the subvolume boundary, but there's no sign of them in > > /proc/mounts (there's no d_automount in btrfs). > > That's what Niel's patch 11/11 is proposing to add and that's the reason > he was asking if this is going to break overlayfs over btrfs. > > My question was, regardless of btrfs, can ovl_lookup() treat automount > dentries gracefully as empty dirs or just read them as is, instead of > returning EREMOTE on lookup? > > The rationale is that we use a private mount and we are not following > across mounts from layers anyway, so what do we care about > auto or manual mounts? I guess that depends on the use cases. If no one cares (as is the case apparently), the simplest is to leave it the way it is. Thanks, Miklos