From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8488B330B2E; Thu, 15 Jan 2026 08:33:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768466014; cv=none; b=OaGmKuIAjiVDhBoB/6KdUISjBgoA44eWGG4YJyZ85MsznRlZ7DOCvO44CuWn9Gqv9srYoTvvdBZ1zZ54JB0uBtMG7qAciwt73DAL3dXFhu7AaQXNo86ykAYuu+OQvrtbe4ZNHEZQESrwjT4ae+2mMSIOLtz9vQs7MPeZ2qTWw0U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768466014; c=relaxed/simple; bh=oLbUH2DPO45fSX51Lz273E+gwrE4TYXAmwzWRgKxagE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=oE4DcCVvskeMkzzPMqouUqsG7F50mRMZRdYSp0FgQ+S/9+6gHE89h+oIs2lWuRLh/fSeIgfPIdu+t1NTPU0ci++IdZQVkyadHTC9LsxrJWblCv0jC1vvNFPtQpehQYnNwxW50c1b4+HsVnvGihsC8593hZljqm9xv2pFM1KEvvw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=c+60rQr7; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="c+60rQr7" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=ggIby7ZJJhhdPb6y5rH3a2GAOEpyxb4btFDkRofMARo=; b=c+60rQr76h1PsKAd5LgZT9hsxs aNKhr+6hZylxOZstJG/1DgKDn3jLBV6CLqh93j+WnurQG7htCVWPbVvx6tOOUVmORqsU2McpPOkHx u9JemdngkpC4GOWQM49sG2cFmQXbWsrsABlaLCyNQvNPEl+M5kVweygSwI21MwVsu9pML78e/uHxP vmIIVXx4fyMCNx3hPFAoWaY/UvrDQx3Aoog9gQ+mt7L4rBcvXKQQLFteJUrzRcG5+ThbjMMlIeFyn n6rc9wHtWg+gNCftYd7qw5Q1lztuERemrK6iJ3CvqvoWgP9e6ucBOBNhWhZlZCMCcpDFLJa8qwA8J WF22tmyA==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vgImu-0000000C08y-0V2p; Thu, 15 Jan 2026 08:33:04 +0000 Date: Thu, 15 Jan 2026 00:33:04 -0800 From: Christoph Hellwig To: Christian Brauner Cc: Christoph Hellwig , Amir Goldstein , Jeff Layton , Chuck Lever , Jan Kara , Luis de Bethencourt , Salah Triki , Nicolas Pitre , Anders Larsen , Alexander Viro , David Sterba , Chris Mason , Gao Xiang , Chao Yu , Yue Hu , Jeffle Xu , Sandeep Dhavale , Hongbo Li , Chunhai Guo , Jan Kara , Theodore Ts'o , Andreas Dilger , Jaegeuk Kim , OGAWA Hirofumi , David Woodhouse , Richard Weinberger , Dave Kleikamp , Ryusuke Konishi , Viacheslav Dubeyko , Konstantin Komarov , Mark Fasheh , Joel Becker , Joseph Qi , Mike Marshall , Martin Brandenburg , Miklos Szeredi , Phillip Lougher , Carlos Maiolino , Hugh Dickins , Baolin Wang , Andrew Morton , Namjae Jeon , Sungjong Seo , Yuezhang Mo , Alexander Aring , Andreas Gruenbacher , Jonathan Corbet , "Matthew Wilcox (Oracle)" , Eric Van Hensbergen , Latchesar Ionkov , Dominique Martinet , Christian Schoenebeck , Xiubo Li , Ilya Dryomov , Trond Myklebust , Anna Schumaker , Steve French , Paulo Alcantara , Ronnie Sahlberg , Shyam Prasad N , Tom Talpey , Bharath SM , Hans de Goede , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-mtd@lists.infradead.org, jfs-discussion@lists.sourceforge.net, linux-nilfs@vger.kernel.org, ntfs3@lists.linux.dev, ocfs2-devel@lists.linux.dev, devel@lists.orangefs.org, linux-unionfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, gfs2@lists.linux.dev, linux-doc@vger.kernel.org, v9fs@lists.linux.dev, ceph-devel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org Subject: Re: [PATCH 00/24] vfs: require filesystems to explicitly opt-in to lease support Message-ID: References: <20260113-mondlicht-raven-82fc4eb70e9d@brauner> <20260114-klarstellen-blamieren-0b7d40182800@brauner> <20260115-inspektion-kochbuch-505d8f94829e@brauner> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260115-inspektion-kochbuch-505d8f94829e@brauner> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Jan 15, 2026 at 09:14:06AM +0100, Christian Brauner wrote: > On Wed, Jan 14, 2026 at 10:42:48PM -0800, Christoph Hellwig wrote: > > On Wed, Jan 14, 2026 at 04:20:13PM +0100, Christian Brauner wrote: > > > > You're still think of it the wrong way. If we do have file systems > > > > that break the original exportfs semantics we need to fix that, and > > > > something like a "stable handles" flag will work well for that. But > > > > a totally arbitrary "is exportable" flag is total nonsense. > > > > > > File handles can legitimately be conceptualized independently of > > > exporting a filesystem. If we wanted to tear those concepts apart > > > implementation wise we could. > > > > > > It is complete nonsense to expect the kernel to support exporting any > > > arbitrary internal filesystem or to not support file handles at all. > > > > You are going even further down the path of entirely missing the point > > (or the two points by now). > > You're arguing for the sake of arguing imho. You're getting exactly what > we're all saying as evidenced by the last paragraph in your mail: it is > entirely what this whole thing is about. I can't even parse what you mean. And no, I hate these stupid arguments, and I have much better things to do than dragging this on. > > If a file systems meets all technical requirements of being nfsd > > exportable and the users asks for it, it is not our job to make an > > arbitrary policy decision to say no. > > This is an entirely irrelevant point because we're talking about > cgroupfs, nsfs, and pidfs. And they don't meet this criteria. cgroupfs > is a _local resource management filesystem_ why would we ever want to > support exporting it over the network. It allows to break the local > delegation model as I've explained. cgroupfs shows _local processes_. So > a server will see completely nonsensical PID identifiers listed in > cgroup files and it can fsck around with processes in a remote system. None of that is a technical argument. The lack of stable file handles would be one, and I think we came to the conclusion yesterday that this is the case.