From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A9F8D3D649F; Tue, 20 Jan 2026 14:12:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768918352; cv=none; b=Ox+SMhnrG1vzGANfC5j6jLGHvCe3NEdvm5emiwNBWNnweOEqN5dGH6W9Zy1c8IMDYhqR9FqtVSa7+LWV8egkMc4uCmu9YjZ1UNcmtqRkfwlVP60tXr/+QWfkP69do1LdfYheyBXRA0ZKYtTJCqGQtSyg3WuzrK1oQ0zC6YntW/M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768918352; c=relaxed/simple; bh=L3E8HhvX87nmou45QKTRtBfQlfrNc6JUH9rmuLWAoZs=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=HuydjLXf4XpCOtO7kKWKze00c1SWp7s5pZV2Rkn1WHNrolLSSjuTsAmjlV8G52Qe5GwK1OfKSAKVqFNln2Mhled7OePJevqj1w7pXXR4pEGAKoaGtMYwJ9sj1Q88xuKMMix5nV8hKnOxGTKGTJGEg0a1QK8aq7acKjdIT3Il5TY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fs1qjXLd; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fs1qjXLd" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8828BC19423; Tue, 20 Jan 2026 14:12:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768918352; bh=L3E8HhvX87nmou45QKTRtBfQlfrNc6JUH9rmuLWAoZs=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=fs1qjXLdXmYtCaveOISFME6KjBkKjb93SreqPvM/VXpZtTME7TbUDB7pUY5qsJkw5 6fuwZGlF1NrNjUlEizRekYSqjMOnShYqpAOqWfJeliIvBrtsjTVxHaNyG+pZCZQ4e2 PlodS/y5xq+O9DKI2i6VKaSJh8YCqvmmXitGD1ToLYIRPwjB1OGytE3TKa6A7LbuzD +5fhNRH0iB3jJX4TstKRcDUCIflQg2FmOVfqdnQaKtnh7Pj2nNfi+rahiAmH5n7j6Y Wc5bt8uWgo78VkXwAi0MoR7eV4eRdIq8Ss/wjOXSmrZlF1nZmPlWL1481755bZUcy3 ytNjAkJhyTlvA== Message-ID: <707f08e114bf603caf7de020bb630d5477e86bca.camel@kernel.org> Subject: Re: [PATCH v2 01/31] Documentation: document EXPORT_OP_NOLOCKS From: Jeff Layton To: Christoph Hellwig Cc: Christian Brauner , Alexander Viro , Chuck Lever , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , Amir Goldstein , Hugh Dickins , Baolin Wang , Andrew Morton , Theodore Ts'o , Andreas Dilger , Jan Kara , Gao Xiang , Chao Yu , Yue Hu , Jeffle Xu , Sandeep Dhavale , Hongbo Li , Chunhai Guo , Carlos Maiolino , Ilya Dryomov , Alex Markuze , Viacheslav Dubeyko , Chris Mason , David Sterba , Luis de Bethencourt , Salah Triki , Phillip Lougher , Steve French , Paulo Alcantara , Ronnie Sahlberg , Shyam Prasad N , Bharath SM , Miklos Szeredi , Mike Marshall , Martin Brandenburg , Mark Fasheh , Joel Becker , Joseph Qi , Konstantin Komarov , Ryusuke Konishi , Trond Myklebust , Anna Schumaker , Dave Kleikamp , David Woodhouse , Richard Weinberger , Jan Kara , Andreas Gruenbacher , OGAWA Hirofumi , Jaegeuk Kim , Jonathan Corbet , David Laight , Dave Chinner , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-ext4@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-xfs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-cifs@vger.kernel.org, samba-technical@lists.samba.org, linux-unionfs@vger.kernel.org, devel@lists.orangefs.org, ocfs2-devel@lists.linux.dev, ntfs3@lists.linux.dev, linux-nilfs@vger.kernel.org, jfs-discussion@lists.sourceforge.net, linux-mtd@lists.infradead.org, gfs2@lists.linux.dev, linux-f2fs-devel@lists.sourceforge.net, linux-doc@vger.kernel.org Date: Tue, 20 Jan 2026 09:12:24 -0500 In-Reply-To: <9b64bed72e43d0bf24e9b1e3bc770c4a87082762.camel@kernel.org> References: <20260119-exportfs-nfsd-v2-0-d93368f903bd@kernel.org> 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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) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2026-01-20 at 08:20 -0500, Jeff Layton wrote: > On Mon, 2026-01-19 at 23:44 -0800, Christoph Hellwig wrote: > > On Mon, Jan 19, 2026 at 11:26:18AM -0500, Jeff Layton wrote: > > > + EXPORT_OP_NOLOCKS - Disable file locking on this filesystem. Some > > > + filesystems cannot properly support file locking as implemented = by > > > + nfsd. A case in point is reexport of NFS itself, which can't be = done > > > + safely without coordinating the grace period handling. Other clu= stered > > > + and networked filesystems can be problematic here as well. > >=20 > > I'm not sure this is very useful. It really needs to document what > > locking semantics nfs expects, because otherwise no reader will know > > if they set this or not. >=20 > Fair point. I'll see if I can draft something better. Suggestions > welcome. How about this? + EXPORT_OP_NOLOCKS - Disable file locking on this filesystem. Filesystems + that want to support locking over NFS must support POSIX file locking + semantics and must handle lock recovery requests from clients after a + reboot. Most local disk, RAM, or pseudo-filesystems use the generic PO= SIX + locking support in the kernel and naturally provide this capability. N= etwork + or clustered filesystems usually need special handling to do this prop= erly. --=20 Jeff Layton