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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B9062C9EC94 for ; Mon, 12 Jan 2026 14:50:33 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2A0826B008A; Mon, 12 Jan 2026 09:50:33 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 26ACD6B008C; Mon, 12 Jan 2026 09:50:33 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1431C6B0092; Mon, 12 Jan 2026 09:50:33 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id F16006B008A for ; Mon, 12 Jan 2026 09:50:32 -0500 (EST) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 9D037160419 for ; Mon, 12 Jan 2026 14:50:32 +0000 (UTC) X-FDA: 84323597904.03.9216EBE Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf06.hostedemail.com (Postfix) with ESMTP id B9CC2180002 for ; Mon, 12 Jan 2026 14:50:30 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=UpMEz5TH; spf=pass (imf06.hostedemail.com: domain of jlayton@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=jlayton@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1768229430; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=cheSnBLxN544y0UKkw10KpgjiO68XnZpyeYuNQCu1SI=; b=CaY3CddikUGUbrE7L0QN8XN8HHlI/gPpuulg1+h9X7RL5DEgqszzLDB9L5ocFOLd72qnDX i8dAKXM/935rXKFZWp+IKnbMq8gngEmFvuv7sQE5X+Ek689JoGHJ5vkUg888p6evAEtWSi n+4noj50OgjsLDp56cRD8iJfwuKvNsg= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=UpMEz5TH; spf=pass (imf06.hostedemail.com: domain of jlayton@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=jlayton@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1768229430; a=rsa-sha256; cv=none; b=Z+547ktRtqDZ0NYka3cksZm4EEbOBt/FiZH+Lg4v8TbHDFN7dv6XHMzY4bkOTLI4oxykzV h5LK0mKJMZbxpMm9CKNa6ZGQNWJu5Y/MQPqSfN023QHxLOxyo+Kkg0ldzYxYqo/DaPn0g2 L3vqq4ipz/M6fmlrTRDBwWa5ImexcKs= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 631B7441BF; Mon, 12 Jan 2026 14:50:29 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E8AEC16AAE; Mon, 12 Jan 2026 14:50:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768229429; bh=cheSnBLxN544y0UKkw10KpgjiO68XnZpyeYuNQCu1SI=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=UpMEz5THVo05QbZ/pAisnu0HRhesOIjE2rYftbA7FBhGQj5tCikdbZP3s9Z/gB+1y k8fYirWnboJmtXtByE43Gev4eWZMrnZp2xsCYHsMHZKKPwK6nyAzNy2SlEd6q6RdQX E9BsB3Zeg8leNoOsSqkZw9UMTUfEJ1CwpbuRjO/ZsHVZdkTGXi72eLukzZew16H4By 2V8I14GVLtY2HkAvnbTAdK8f8SFRaA/5FSsShCjCBoX+/4KLO8Va98nCZCU0IF7NSt 5mEIqfFpYxDWcq+lTy0EQTI0buuA/J9QluBW76YeWrm5Yt8NF684D6eD5hHIR3dAHu cDKQUbKLqjwJw== Message-ID: Subject: Re: [PATCH 00/24] vfs: require filesystems to explicitly opt-in to lease support From: Jeff Layton To: Chuck Lever , Amir Goldstein , Christian Brauner Cc: Jan Kara , Luis de Bethencourt , Salah Triki , Nicolas Pitre , Christoph Hellwig , 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 Date: Mon, 12 Jan 2026 09:50:20 -0500 In-Reply-To: References: <20260108-setlease-6-20-v1-0-ea4dec9b67fa@kernel.org> <8af369636c32b868f83669c49aea708ca3b894ac.camel@kernel.org> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV YrOOI5VGLHge0awt7bhMCTM9KAfPc+xL/ZxAMVWd3NCk5SamL2cE99UWgtvNOIYU8m6EjTLhsj8sn VluJH0/RcxEeFbnSaswVChNSGa7mXJrTR22lRL6ZPjdMgS2Km90haWPRc8Wolcz07Y2se0xpGVLEQ cDEsvv5IMmeMe1/qLZ6NaVkNuL3WOXvxaVT9USW1+/SGipO2IpKJjeDZfehlB/kpfF24+RrK+seQf CBYyUE8QJpvTZyfUHNYldXlrjO6n5MdOempLqWpfOmcGkwnyNRBR46g/jf8KnPRwXs509yAqDB6sE LZH+yWr9LQZEwARAQABtCVKZWZmIExheXRvbiA8amxheXRvbkBwb29jaGllcmVkcy5uZXQ+iQI7BB MBAgAlAhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAUCTpXWPAIZAQAKCRAADmhBGVaCFc65D/4 gBLNMHopQYgG/9RIM3kgFCCQV0pLv0hcg1cjr+bPI5f1PzJoOVi9s0wBDHwp8+vtHgYhM54yt43uI 7Htij0RHFL5eFqoVT4TSfAg2qlvNemJEOY0e4daljjmZM7UtmpGs9NN0r9r50W82eb5Kw5bc/r0km R/arUS2st+ecRsCnwAOj6HiURwIgfDMHGPtSkoPpu3DDp/cjcYUg3HaOJuTjtGHFH963B+f+hyQ2B rQZBBE76ErgTDJ2Db9Ey0kw7VEZ4I2nnVUY9B5dE2pJFVO5HJBMp30fUGKvwaKqYCU2iAKxdmJXRI ONb7dSde8LqZahuunPDMZyMA5+mkQl7kpIpR6kVDIiqmxzRuPeiMP7O2FCUlS2DnJnRVrHmCljLkZ Wf7ZUA22wJpepBligemtSRSbqCyZ3B48zJ8g5B8xLEntPo/NknSJaYRvfEQqGxgk5kkNWMIMDkfQO lDSXZvoxqU9wFH/9jTv1/6p8dHeGM0BsbBLMqQaqnWiVt5mG92E1zkOW69LnoozE6Le+12DsNW7Rj iR5K+27MObjXEYIW7FIvNN/TQ6U1EOsdxwB8o//Yfc3p2QqPr5uS93SDDan5ehH59BnHpguTc27Xi QQZ9EGiieCUx6Zh2ze3X2UW9YNzE15uKwkkuEIj60NvQRmEDfweYfOfPVOueC+iFifbQgSmVmZiBM YXl0b24gPGpsYXl0b25AcmVkaGF0LmNvbT6JAjgEEwECACIFAk6V0q0CGwMGCwkIBwMCBhUIAgkKC wQWAgMBAh4BAheAAAoJEAAOaEEZVoIViKUQALpvsacTMWWOd7SlPFzIYy2/fjvKlfB/Xs4YdNcf9q LqF+lk2RBUHdR/dGwZpvw/OLmnZ8TryDo2zXVJNWEEUFNc7wQpl3i78r6UU/GUY/RQmOgPhs3epQC 3PMJj4xFx+VuVcf/MXgDDdBUHaCTT793hyBeDbQuciARDJAW24Q1RCmjcwWIV/pgrlFa4lAXsmhoa c8UPc82Ijrs6ivlTweFf16VBc4nSLX5FB3ls7S5noRhm5/Zsd4PGPgIHgCZcPgkAnU1S/A/rSqf3F LpU+CbVBDvlVAnOq9gfNF+QiTlOHdZVIe4gEYAU3CUjbleywQqV02BKxPVM0C5/oVjMVx3bri75n1 TkBYGmqAXy9usCkHIsG5CBHmphv9MHmqMZQVsxvCzfnI5IO1+7MoloeeW/lxuyd0pU88dZsV/riHw 87i2GJUJtVlMl5IGBNFpqoNUoqmvRfEMeXhy/kUX4Xc03I1coZIgmwLmCSXwx9MaCPFzV/dOOrju2 xjO+2sYyB5BNtxRqUEyXglpujFZqJxxau7E0eXoYgoY9gtFGsspzFkVNntamVXEWVVgzJJr/EWW0y +jNd54MfPRqH+eCGuqlnNLktSAVz1MvVRY1dxUltSlDZT7P2bUoMorIPu8p7ZCg9dyX1+9T6Muc5d Hxf/BBP/ir+3e8JTFQBFOiLNdFtB9KZWZmIExheXRvbiA8amxheXRvbkBzYW1iYS5vcmc+iQI4BBM BAgAiBQJOldK9AhsDBgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRAADmhBGVaCFWgWD/0ZRi4h N9FK2BdQs9RwNnFZUr7JidAWfCrs37XrA/56olQl3ojn0fQtrP4DbTmCuh0SfMijB24psy1GnkPep naQ6VRf7Dxg/Y8muZELSOtsv2CKt3/02J1BBitrkkqmHyni5fLLYYg6fub0T/8Kwo1qGPdu1hx2BQ RERYtQ/S5d/T0cACdlzi6w8rs5f09hU9Tu4qV1JLKmBTgUWKN969HPRkxiojLQziHVyM/weR5Reu6 FZVNuVBGqBD+sfk/c98VJHjsQhYJijcsmgMb1NohAzwrBKcSGKOWJToGEO/1RkIN8tqGnYNp2G+aR 685D0chgTl1WzPRM6mFG1+n2b2RR95DxumKVpwBwdLPoCkI24JkeDJ7lXSe3uFWISstFGt0HL8Eew P8RuGC8s5h7Ct91HMNQTbjgA+Vi1foWUVXpEintAKgoywaIDlJfTZIl6Ew8ETN/7DLy8bXYgq0Xzh aKg3CnOUuGQV5/nl4OAX/3jocT5Cz/OtAiNYj5mLPeL5z2ZszjoCAH6caqsF2oLyAnLqRgDgR+wTQ T6gMhr2IRsl+cp8gPHBwQ4uZMb+X00c/Amm9VfviT+BI7B66cnC7Zv6Gvmtu2rEjWDGWPqUgccB7h dMKnKDthkA227/82tYoFiFMb/NwtgGrn5n2vwJyKN6SEoygGrNt0SI84y6hEVbQlSmVmZiBMYXl0b 24gPGpsYXl0b25AcHJpbWFyeWRhdGEuY29tPokCOQQTAQIAIwUCU4xmKQIbAwcLCQgHAwIBBhUIAg kKCwQWAgMBAh4BAheAAAoJEAAOaEEZVoIV1H0P/j4OUTwFd7BBbpoSp695qb6HqCzWMuExsp8nZjr uymMaeZbGr3OWMNEXRI1FWNHMtcMHWLP/RaDqCJil28proO+PQ/yPhsr2QqJcW4nr91tBrv/MqItu AXLYlsgXqp4BxLP67bzRJ1Bd2x0bWXurpEXY//VBOLnODqThGEcL7jouwjmnRh9FTKZfBDpFRaEfD FOXIfAkMKBa/c9TQwRpx2DPsl3eFWVCNuNGKeGsirLqCxUg5kWTxEorROppz9oU4HPicL6rRH22Ce 6nOAON2vHvhkUuO3GbffhrcsPD4DaYup4ic+DxWm+DaSSRJ+e1yJvwi6NmQ9P9UAuLG93S2MdNNbo sZ9P8k2mTOVKMc+GooI9Ve/vH8unwitwo7ORMVXhJeU6Q0X7zf3SjwDq2lBhn1DSuTsn2DbsNTiDv qrAaCvbsTsw+SZRwF85eG67eAwouYk+dnKmp1q57LDKMyzysij2oDKbcBlwB/TeX16p8+LxECv51a sjS9TInnipssssUDrHIvoTTXWcz7Y5wIngxDFwT8rPY3EggzLGfK5Zx2Q5S/N0FfmADmKknG/D8qG IcJE574D956tiUDKN4I+/g125ORR1v7bP+OIaayAvq17RP+qcAqkxc0x8iCYVCYDouDyNvWPGRhbL UO7mlBpjW9jK9e2fvZY9iw3QzIPGKtClKZWZmIExheXRvbiA8amVmZi5sYXl0b25AcHJpbWFyeWRh dGEuY29tPokCOQQTAQIAIwUCU4xmUAIbAwcLCQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJEAAOa EEZVoIVzJoQALFCS6n/FHQS+hIzHIb56JbokhK0AFqoLVzLKzrnaeXhE5isWcVg0eoV2oTScIwUSU apy94if69tnUo4Q7YNt8/6yFM6hwZAxFjOXR0ciGE3Q+Z1zi49Ox51yjGMQGxlakV9ep4sV/d5a50 M+LFTmYSAFp6HY23JN9PkjVJC4PUv5DYRbOZ6Y1+TfXKBAewMVqtwT1Y+LPlfmI8dbbbuUX/kKZ5d dhV2736fgyfpslvJKYl0YifUOVy4D1G/oSycyHkJG78OvX4JKcf2kKzVvg7/Rnv+AueCfFQ6nGwPn 0P91I7TEOC4XfZ6a1K3uTp4fPPs1Wn75X7K8lzJP/p8lme40uqwAyBjk+IA5VGd+CVRiyJTpGZwA0 jwSYLyXboX+Dqm9pSYzmC9+/AE7lIgpWj+3iNisp1SWtHc4pdtQ5EU2SEz8yKvDbD0lNDbv4ljI7e flPsvN6vOrxz24mCliEco5DwhpaaSnzWnbAPXhQDWb/lUgs/JNk8dtwmvWnqCwRqElMLVisAbJmC0 BhZ/Ab4sph3EaiZfdXKhiQqSGdK4La3OTJOJYZphPdGgnkvDV9Pl1QZ0ijXQrVIy3zd6VCNaKYq7B AKidn5g/2Q8oio9Tf4XfdZ9dtwcB+bwDJFgvvDYaZ5bI3ln4V3EyW5i2NfXazz/GA/I/ZtbsigCFc 8ftCBKZWZmIExheXRvbiA8amxheXRvbkBrZXJuZWwub3JnPokCOAQTAQIAIgUCWe8u6AIbAwYLCQg HAwIGFQgCCQoLBBYCAwECHgECF4AACgkQAA5oQRlWghUuCg/+Lb/xGxZD2Q1oJVAE37uW308UpVSD 2tAMJUvFTdDbfe3zKlPDTuVsyNsALBGclPLagJ5ZTP+Vp2irAN9uwBuacBOTtmOdz4ZN2tdvNgozz uxp4CHBDVzAslUi2idy+xpsp47DWPxYFIRP3M8QG/aNW052LaPc0cedYxp8+9eiVUNpxF4SiU4i9J DfX/sn9XcfoVZIxMpCRE750zvJvcCUz9HojsrMQ1NFc7MFT1z3MOW2/RlzPcog7xvR5ENPH19ojRD CHqumUHRry+RF0lH00clzX/W8OrQJZtoBPXv9ahka/Vp7kEulcBJr1cH5Wz/WprhsIM7U9pse1f1g Yy9YbXtWctUz8uvDR7shsQxAhX3qO7DilMtuGo1v97I/Kx4gXQ52syh/w6EBny71CZrOgD6kJwPVV AaM1LRC28muq91WCFhs/nzHozpbzcheyGtMUI2Ao4K6mnY+3zIuXPygZMFr9KXE6fF7HzKxKuZMJO aEZCiDOq0anx6FmOzs5E6Jqdpo/mtI8beK+BE7Va6ni7YrQlnT0i3vaTVMTiCThbqsB20VrbMjlhp f8lfK1XVNbRq/R7GZ9zHESlsa35ha60yd/j3pu5hT2xyy8krV8vGhHvnJ1XRMJBAB/UYb6FyC7S+m QZIQXVeAA+smfTT0tDrisj1U5x6ZB9b3nBg65kc= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.2 (3.58.2-1.fc43) MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: B9CC2180002 X-Stat-Signature: gxqozzgfm7qy1szku44gagjah15dm6p6 X-HE-Tag: 1768229430-953791 X-HE-Meta: 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 gydHNdu1 VRgQLN9PZFDr4XGMhkd5IaS/ecBa1D5vh9x9wQPPxm5e57w80onkK409J0IDMq5jgo7bDdtlfnVwC+g5B9gE6Pauc8/bsPCvNvj/mzBaJJl3JaHZSNVWme67xKPj7cKr36ej+5Fkbp0PyqOWuK6kaOmIgr9Av64vBUFxwvXKxc+RaR5taCFB885wj8+pBDvGejgif8BqWagUtD7tcSWr0fDweaM6th2m+U4v7/cqVrMrkg6YrOz6WJtY3N1AfaMlPp/tkbRb6q6Ky0i/RWt+a4C2UO/hVSWLLJsuFSIsxqrF6DUbAwjsKRnX3Fg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, 2026-01-12 at 09:31 -0500, Chuck Lever wrote: > On 1/12/26 8:34 AM, Jeff Layton wrote: > > On Fri, 2026-01-09 at 19:52 +0100, Amir Goldstein wrote: > > > On Thu, Jan 8, 2026 at 7:57=E2=80=AFPM Jeff Layton wrote: > > > >=20 > > > > On Thu, 2026-01-08 at 18:40 +0100, Jan Kara wrote: > > > > > On Thu 08-01-26 12:12:55, Jeff Layton wrote: > > > > > > Yesterday, I sent patches to fix how directory delegation suppo= rt is > > > > > > handled on filesystems where the should be disabled [1]. That s= et is > > > > > > appropriate for v6.19. For v7.0, I want to make lease support b= e more > > > > > > opt-in, rather than opt-out: > > > > > >=20 > > > > > > For historical reasons, when ->setlease() file_operation is set= to NULL, > > > > > > the default is to use the kernel-internal lease implementation.= This > > > > > > means that if you want to disable them, you need to explicitly = set the > > > > > > ->setlease() file_operation to simple_nosetlease() or the equiv= alent. > > > > > >=20 > > > > > > This has caused a number of problems over the years as some fil= esystems > > > > > > have inadvertantly allowed leases to be acquired simply by havi= ng left > > > > > > it set to NULL. It would be better if filesystems had to opt-in= to lease > > > > > > support, particularly with the advent of directory delegations. > > > > > >=20 > > > > > > This series has sets the ->setlease() operation in a pile of ex= isting > > > > > > local filesystems to generic_setlease() and then changes > > > > > > kernel_setlease() to return -EINVAL when the setlease() operati= on is not > > > > > > set. > > > > > >=20 > > > > > > With this change, new filesystems will need to explicitly set t= he > > > > > > ->setlease() operations in order to provide lease and delegatio= n > > > > > > support. > > > > > >=20 > > > > > > I mainly focused on filesystems that are NFS exportable, since = NFS and > > > > > > SMB are the main users of file leases, and they tend to end up = exporting > > > > > > the same filesystem types. Let me know if I've missed any. > > > > >=20 > > > > > So, what about kernfs and fuse? They seem to be exportable and do= n't have > > > > > .setlease set... > > > > >=20 > > > >=20 > > > > Yes, FUSE needs this too. I'll add a patch for that. > > > >=20 > > > > As far as kernfs goes: AIUI, that's basically what sysfs and resctr= l > > > > are built on. Do we really expect people to set leases there? > > > >=20 > > > > I guess it's technically a regression since you could set them on t= hose > > > > sorts of files earlier, but people don't usually export kernfs base= d > > > > filesystems via NFS or SMB, and that seems like something that coul= d be > > > > used to make mischief. > > > >=20 > > > > AFAICT, kernfs_export_ops is mostly to support open_by_handle_at().= See > > > > commit aa8188253474 ("kernfs: add exportfs operations"). > > > >=20 > > > > One idea: we could add a wrapper around generic_setlease() for > > > > filesystems like this that will do a WARN_ONCE() and then call > > > > generic_setlease(). That would keep leases working on them but we m= ight > > > > get some reports that would tell us who's setting leases on these f= iles > > > > and why. > > >=20 > > > IMO, you are being too cautious, but whatever. > > >=20 > > > It is not accurate that kernfs filesystems are NFS exportable in gene= ral. > > > Only cgroupfs has KERNFS_ROOT_SUPPORT_EXPORTOP. > > >=20 > > > If any application is using leases on cgroup files, it must be some > > > very advanced runtime (i.e. systemd), so we should know about the > > > regression sooner rather than later. > > >=20 > >=20 > > I think so too. For now, I think I'll not bother with the WARN_ONCE(). > > Let's just leave kernfs out of the set until someone presents a real > > use-case. > >=20 > > > There are also the recently added nsfs and pidfs export_operations. > > >=20 > > > I have a recollection about wanting to be explicit about not allowing > > > those to be exportable to NFS (nsfs specifically), but I can't see wh= ere > > > and if that restriction was done. > > >=20 > > > Christian? Do you remember? > > >=20 > >=20 > > (cc'ing Chuck) > >=20 > > FWIW, you can currently export and mount /sys/fs/cgroup via NFS. The > > directory doesn't show up when you try to get to it via NFSv4, but you > > can mount it using v3 and READDIR works. The files are all empty when > > you try to read them. I didn't try to do any writes. > >=20 > > Should we add a mechanism to prevent exporting these sorts of > > filesystems? > >=20 > > Even better would be to make nfsd exporting explicitly opt-in. What if > > we were to add a EXPORT_OP_NFSD flag that explicitly allows filesystems > > to opt-in to NFS exporting, and check for that in __fh_verify()? We'd > > have to add it to a bunch of existing filesystems, but that's fairly > > simple to do with an LLM. >=20 > What's the active harm in exporting /sys/fs/cgroup ? It has to be done > explicitly via /etc/exports, so this is under the NFS server admin's > control. Is it an attack surface? >=20 Potentially? I don't see any active harm with exporting cgroupfs. It doesn't work right via nfsd, but it's not crashing the box or anything. At one time, those were only defined by filesystems that wanted to allow NFS export. Now we've grown them on filesystems that just want to provide filehandles for open_by_handle_at() and the like. nfsd doesn't care though: if the fs has export operations, it'll happily use them. Having an explicit "I want to allow nfsd" flag see ms like it might save us some headaches in the future when other filesystems add export ops for this sort of filehandle use. --=20 Jeff Layton