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 Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 22A62D2ECF7 for ; Tue, 20 Jan 2026 10:32:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.sourceforge.net; s=beta; h=Content-Transfer-Encoding:Content-Type:Cc: Reply-To:From:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:Subject:In-Reply-To:MIME-Version:References: Message-ID:To:Date:Sender:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=lyGcK5Nboult4PmogzijZzl6qddsVO4EBTWh8HSt25w=; b=KJsAVoAhx+x5PufLcJ6CFBWCa6 d6F9IchHWvVCqUTndYbtPK5kpfSfxT04JGg/rU7CsdgwaKHXf+AuuduoZFqrpyxlFnV1LhbvXBasO SDe4PkS6l80BTbTasEJ10JFfCSxnmHEG+QHeWdmFYY8jQrHlDnk6ZMrL9NZfa+tqc76g=; Received: from [127.0.0.1] (helo=sfs-ml-4.v29.lw.sourceforge.com) by sfs-ml-4.v29.lw.sourceforge.com with esmtp (Exim 4.95) (envelope-from ) id 1vi92A-0001wr-5D; Tue, 20 Jan 2026 10:32:26 +0000 Received: from [172.30.29.66] (helo=mx.sourceforge.net) by sfs-ml-4.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1vi928-0001wa-2L; Tue, 20 Jan 2026 10:32:24 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; 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:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=GIPzDp4//6enUE/aZW6TaDiQzaEzpTggtDW+VnkFMJ8=; b=c3h2f5jIk3CuDKtbtUIuu+d9hf e5SUtD60YVb8pMYdglKK0EkkyAXOxM8YYkZOuxkENFlKil85ej7c+upY6xB+byRFrBxm40oxcqK4k ZcxB81Ccs7f21B1RalAH/2iJDiCcAQBXdoyHxyUuj5KduwGQ9NdAeECZPK3xhfE46Los=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; 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:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=GIPzDp4//6enUE/aZW6TaDiQzaEzpTggtDW+VnkFMJ8=; b=E8BKnrwHw/Vpx1AZjmOuijGDut YHBplhHAT2Xgck4MdF5cFSliRP7WpMf6W4fX6zZjft/fX73ZZt5XNYzkMkN17aiHl8t+VrqZx9n4j RSJ73Qr02GQwIgzJyZry2yh5k3AX7jArgyKWFbUvuHk0XhunJ+opd7eaow6NaBuL8q2s=; Received: from tor.source.kernel.org ([172.105.4.254]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.95) id 1vi927-0003jy-Bo; Tue, 20 Jan 2026 10:32:24 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 4E44E60018; Tue, 20 Jan 2026 10:32:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2A27C16AAE; Tue, 20 Jan 2026 10:31:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768905132; bh=TXpuEn3+iHgMswY7v2yl+yBnFlWexn06CYVhrLra0ps=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=sYn1JLyPJPiGC80xsPWNxbtykfUUs946DA7esf6l3JMX38rt0GRoNF1cRYsres/wk PEJViML67kDs58KnQ01Y/RlO5bKq7d0ZXMcSQ/mkeXLjjLZV/fDEUuF8X1z67vGwDl S4BDLlAOBnwFrMcS0CNaziW6IFGszNB0/JTGCLvnEXaABq+5D8szxy7iodrNzItOUv lpWjW+neeYAI9cglsT/f5525FKsTcWuHVc8VwgMC9LA2j5BhSVKDtyEXhQPSbOCGl2 KQoI5KR3jG9uCQrTTBeQZHZsxSZCqULdPd8KRVm4QkItj+8BOixBLgQenBp1VoSz3y OcHgGkgocKzkA== Date: Tue, 20 Jan 2026 11:31:54 +0100 To: NeilBrown Message-ID: <20260120-hacken-revision-88209121ac2c@brauner> References: <20260115-exportfs-nfsd-v1-0-8e80160e3c0c@kernel.org> <9c99197dde2eafa55a1b55dce2f0d4d02c77340a.camel@kernel.org> <176877859306.16766.15009835437490907207@noble.neil.brown.name> <176880736225.16766.4203157325432990313@noble.neil.brown.name> <20260119-kanufahren-meerjungfrau-775048806544@brauner> <176885553525.16766.291581709413217562@noble.neil.brown.name> <20260120-entmilitarisieren-wanken-afd04b910897@brauner> <176890211061.16766.16354247063052030403@noble.neil.brown.name> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <176890211061.16766.16354247063052030403@noble.neil.brown.name> X-Headers-End: 1vi927-0003jy-Bo Subject: Re: [f2fs-dev] [PATCH 00/29] fs: require filesystems to explicitly opt-in to nfsd export support X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Christian Brauner via Linux-f2fs-devel Reply-To: Christian Brauner Cc: Martin Brandenburg , jfs-discussion@lists.sourceforge.net, Jan Kara , Paulo Alcantara , Alex Markuze , Sandeep Dhavale , linux-btrfs@vger.kernel.org, Carlos Maiolino , Amir Goldstein , linux-unionfs@vger.kernel.org, Konstantin Komarov , Chris Mason , Andreas Dilger , Chunhai Guo , Ronnie Sahlberg , linux-mtd@lists.infradead.org, Mike Marshall , linux-xfs@vger.kernel.org, linux-nilfs@vger.kernel.org, Yue Hu , Miklos Szeredi , Richard Weinberger , Mark Fasheh , Hugh Dickins , Dai Ngo , Ryusuke Konishi , Christoph Hellwig , Viacheslav Dubeyko , Gao Xiang , linux-ext4@vger.kernel.org, Salah Triki , linux-mm@kvack.org, devel@lists.orangefs.org, Shyam Prasad N , Olga Kornievskaia , linux-cifs@vger.kernel.org, Dave Kleikamp , Tom Talpey , ocfs2-devel@lists.linux.dev, Bharath SM , David Sterba , Alexander Viro , Baolin Wang , Jeffle Xu , Jaegeuk Kim , ceph-devel@vger.kernel.org, Ilya Dryomov , OGAWA Hirofumi , Andreas Gruenbacher , gfs2@lists.linux.dev, linux-nfs@vger.kernel.org, Theodore Ts'o , Luis de Bethencourt , Joseph Qi , linux-erofs@lists.ozlabs.org, Jeff Layton , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, Steve French , Chuck Lever , Hongbo Li , Anna Schumaker , Jan Kara , linux-fsdevel@vger.kernel.org, Phillip Lougher , Andrew Morton , ntfs3@lists.linux.dev, David Woodhouse , Trond Myklebust , Joel Becker Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On Tue, Jan 20, 2026 at 08:41:50PM +1100, NeilBrown wrote: > On Tue, 20 Jan 2026, Christian Brauner wrote: > > On Tue, Jan 20, 2026 at 07:45:35AM +1100, NeilBrown wrote: > > > On Mon, 19 Jan 2026, Christian Brauner wrote: > > > > On Mon, Jan 19, 2026 at 06:22:42PM +1100, NeilBrown wrote: > > > > > On Mon, 19 Jan 2026, Christoph Hellwig wrote: > > > > > > On Mon, Jan 19, 2026 at 10:23:13AM +1100, NeilBrown wrote: > > > > > > > > This was Chuck's suggested name. His point was that STABLE means that > > > > > > > > the FH's don't change during the lifetime of the file. > > > > > > > > > > > > > > > > I don't much care about the flag name, so if everyone likes PERSISTENT > > > > > > > > better I'll roll with that. > > > > > > > > > > > > > > I don't like PERSISTENT. > > > > > > > I'd rather call a spade a spade. > > > > > > > > > > > > > > EXPORT_OP_SUPPORTS_NFS_EXPORT > > > > > > > or > > > > > > > EXPORT_OP_NOT_NFS_COMPATIBLE > > > > > > > > > > > > > > The issue here is NFS export and indirection doesn't bring any benefits. > > > > > > > > > > > > No, it absolutely is not. And the whole concept of calling something > > > > > > after the initial or main use is a recipe for a mess. > > > > > > > > > > We are calling it for it's only use. If there was ever another use, we > > > > > could change the name if that made sense. It is not a public name, it > > > > > is easy to change. > > > > > > > > > > > > > > > > > Pick a name that conveys what the flag is about, and document those > > > > > > semantics well. This flag is about the fact that for a given file, > > > > > > as long as that file exists in the file system the handle is stable. > > > > > > Both stable and persistent are suitable for that, nfs is everything > > > > > > but. > > > > > > > > > > My understanding is that kernfs would not get the flag. > > > > > kernfs filehandles do not change as long as the file exist. > > > > > But this is not sufficient for the files to be usefully exported. > > > > > > > > > > I suspect kernfs does re-use filehandles relatively soon after the > > > > > file/object has been destroyed. Maybe that is the real problem here: > > > > > filehandle reuse, not filehandle stability. > > > > > > > > > > Jeff: could you please give details (and preserve them in future cover > > > > > letters) of which filesystems are known to have problems and what > > > > > exactly those problems are? > > > > > > > > > > > > > > > > > Remember nfs also support volatile file handles, and other applications > > > > > > might rely on this (I know of quite a few user space applications that > > > > > > do, but they are kinda hardwired to xfs anyway). > > > > > > > > > > The NFS protocol supports volatile file handles. knfsd does not. > > > > > So maybe > > > > > EXPORT_OP_NOT_NFSD_COMPATIBLE > > > > > might be better. or EXPORT_OP_NOT_LINUX_NFSD_COMPATIBLE. > > > > > (I prefer opt-out rather than opt-in because nfsd export was the > > > > > original purpose of export_operations, but it isn't something > > > > > I would fight for) > > > > > > > > I prefer one of the variants you proposed here but I don't particularly > > > > care. It's not a hill worth dying on. So if Christoph insists on the > > > > other name then I say let's just go with it. > > > > > > > > > > This sounds like you are recommending that we give in to bullying. > > > I would rather the decision be made based on the facts of the case, not > > > the opinions that are stated most bluntly. > > > > > > I actually think that what Christoph wants is actually quite different > > > from what Jeff wants, and maybe two flags are needed. But I don't yet > > > have a clear understanding of what Christoph wants, so I cannot be sure. > > > > I've tried to indirectly ask whether you would be willing to compromise > > here or whether you want to insist on your alternative name. Apparently > > that didn't come through. > > This would be the "not a hill worthy dying on" part of your statement. > I think I see that implication now. > But no, I don't think compromise is relevant. I think the problem > statement as originally given by Jeff is misleading, and people have > been misled to an incorrect name. > > > > > I'm unclear what your goal is in suggesting that I recommend "we" give > > into bullying. All it achieved was to further derail this thread. > > > > The "We" is the same as the "us" in "let's just go with it". > > > > I also think it's not very helpful at v6 of the discussion to start > > figuring out what the actual key rift between Jeff's and Christoph's > > position is. If you've figured it out and gotten an agreement and this > > is already in, send a follow-up series. > > v6? v2 was posted today. But maybe you are referring the some other > precursors. > > The introductory statement in v2 is > > This patchset adds a flag that indicates whether the filesystem supports > stable filehandles (i.e. that they don't change over the life of the > file). It then makes any filesystem that doesn't set that flag > ineligible for nfsd export. > > Nobody else questioned the validity of that. I do. > No evidence was given that there are *any* filesystems that don't > support stable filehandles. The only filesystem mentioned is cgroups > and it DOES provide stable filehandles. Oh yes we did. And this is a merry-go-round. It is very much fine for a filesystems to support file handles without wanting to support exporting via NFS. That is especially true for in-kernel pseudo filesystems. As I've said before multiple times I want a way to allow filesystems such as pidfs and nsfs to use file handles without supporting export. Whatever that fscking flag is called at this point I fundamentally don't care. And we are reliving the same arguments over and over. I will _hard NAK_ anything that starts mandating that export of filesystems must be allowed simply because their file handles fit export criteria. I do not care whether pidfs or nsfs file handles fit the bill. They will not be exported. _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel