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=-2.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,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 DD51FC432BE for ; Fri, 27 Aug 2021 23:46:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B7CD360EB5 for ; Fri, 27 Aug 2021 23:46:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232474AbhH0XrG (ORCPT ); Fri, 27 Aug 2021 19:47:06 -0400 Received: from mta-202a.oxsus-vadesecure.net ([51.81.232.240]:39863 "EHLO mta-202a.oxsus-vadesecure.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232354AbhH0XrF (ORCPT ); Fri, 27 Aug 2021 19:47:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; bh=0i9aQdbDO8ks0bCK/A+r6narC3jZD9keCdHdRe Pli1A=; c=relaxed/relaxed; d=earthlink.net; h=from:reply-to:subject: date:to:cc:resent-date:resent-from:resent-to:resent-cc:in-reply-to: references:list-id:list-help:list-unsubscribe:list-subscribe:list-post: list-owner:list-archive; q=dns/txt; s=dk12062016; t=1630107972; x=1630712772; b=MifO8Bf8bQhb95kT7K/ZLzBeV7+yR8NHJyKD80IEqwtYjECnSC5B9If dWH+L6NDF9YS9YQuVYPPHVVICgcnnRo4W0glMGhCbHKS5jMzxhE0AI1eqI8avb5DH8dTlPj mz/c9DqL3XOa4F6AcEulNyVwN1SDtNVby8eNT3yeNGLVQrDS3jN6sOoG/RX5PV8DO0hn0z9 s3U6VfQeNb9LLyG3Ij/fH1Wf1Nc/zHkkuu312I6vvIn50GMXHN5GgwLTpV+A6VPdiBpQx6y pGzklmIjWVe0LK+uPLw8uFiF/bbLLCJ7zCJy0YGasxWyrAuMvmBaYKWnxZUAovsqeuW11ur 7XQ== Received: from FRANKSTHINKPAD ([76.105.143.216]) by smtp.oxsus-vadesecure.net ESMTP oxsus2nmtao02p with ngmta id 967ea5f6-169f4e9080a5b3d6; Fri, 27 Aug 2021 23:46:12 +0000 From: "Frank Filz" To: "'NeilBrown'" Cc: "'J. Bruce Fields'" , "'Chuck Lever'" , , "'Josef Bacik'" References: <162995209561.7591.4202079352301963089@noble.neil.brown.name>, <162995778427.7591.11743795294299207756@noble.neil.brown.name>, <20210826201916.GB10730@fieldses.org>, <163001583884.7591.13328510041463261313@noble.neil.brown.name>, <002901d79b53$41ddba40$c5992ec0$@mindspring.com> <163010502766.7591.10398654528737145909@noble.neil.brown.name> In-Reply-To: <163010502766.7591.10398654528737145909@noble.neil.brown.name> Subject: RE: [PATCH v2] BTRFS/NFSD: provide more unique inode number for btrfs export Date: Fri, 27 Aug 2021 16:46:12 -0700 Message-ID: <005801d79b9d$b8437b80$28ca7280$@mindspring.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Mailer: Microsoft Outlook 15.0 Content-Language: en-us Thread-Index: AQIrHUOuRItKwhPpv5iuHWFXVceYzwFdY2wGAcm0L1ICXkcdJQIF8dZtApre6XOqj8wKwA== Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org > On Sat, 28 Aug 2021, Frank Filz wrote: > > > > Changing the fsid for sub-volumes is Ganesha's solution (before = adding > > that, we couldn't even export the sub-volumes at all). >=20 > What does Ganesha use for the mounted-on-fileid? There doesn't seem to = be an > "obvious" answer so I wonder what was chosen. We only make mounted_on_fileid different from fileid on our export = boundaries, and even then, it's not a terribly correct thing for = FSAL_VFS (our module for interfacing with kernel filesystems) since user = space to my knowledge has no way to get any information on an inode that = serves as a mount point. What clients actually do anything with mounted_on_fileid, and what sorts = of things do they do with it? I know the AIX client was interested in it = (from having worked on security negotiation back in 2006), but I have = never been able to test Ganesha with an AIX client. For normal Linux = client operations, what Ganesha does seems to work OK. > > > > Mangling the fileid is definitely the best solution if there will be = lots of sub- > volumes. For a few sub-volumes changing fsid does create additional = mount > points on the client with some issues, but does guarantee there will = be no fileid > collision. > > > > My gut feel is your solution is the best one and Ganesha may need to = switch to > that solution. >=20 > Thanks for the encouragement. Changing the fsid does seem easier is = many > ways, but I don't really like the consequences or implications. Yea, there really isn't a good solution here. Probably really client applications need to do something different to = detect infinite loops and not care so much about unique fileids. Frank