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 53BB9D3EE92 for ; Thu, 22 Jan 2026 17:04:39 +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=ydekLp5YFEdJwrmLfOh/e4f3jgVZ57WMSK4m8EaXxU4=; b=DZ3iWsOkzTd1odOqDwL2xZsibP frMHTN8y3YieJm/hjb2G9/cRBEk5fuUXkxZdKxI+YHTaGXILqzseCywCaXXH6tnt3Y1vYeC0hUBmu 56x/UevwST0yxqeKiwtNyusfdZ7iyspmwaivlkpU1xecWekkG/caE64FhlzML/xPWzCo=; Received: from [127.0.0.1] (helo=sfs-ml-3.v29.lw.sourceforge.com) by sfs-ml-3.v29.lw.sourceforge.com with esmtp (Exim 4.95) (envelope-from ) id 1viy6n-0004RI-Fo; Thu, 22 Jan 2026 17:04:37 +0000 Received: from [172.30.29.66] (helo=mx.sourceforge.net) by sfs-ml-3.v29.lw.sourceforge.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1viy6l-0004R2-LE; Thu, 22 Jan 2026 17:04:35 +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=qs+XaS+FGKy5XGjHxsh2yZR3UAuTtojhMQnjtTVwQfA=; b=DQJpdVxcLrPN39oG3XjU67yA+G QiPmlJLZtYrmvsabCRcomxkgyxXhoWmzR5T9KckaCMfidihlh1xwFnrFusLwXUxD0QGhYd0IvJRDi +SDD+6ijzm9hAxr/HdHZwNOo0p8KnVbRc5Hn+cgYrmgguOK6MVwzZP5mfCGC425gTd6w=; 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=qs+XaS+FGKy5XGjHxsh2yZR3UAuTtojhMQnjtTVwQfA=; b=h1q9CMJ2tihlWsCDfQAryEZXlW stGrFrnIi7ciusukVFBG8Gf9AtL3dhh2iCfcRmrrVYkchafxBzjZ/Sej/xFAjgPkOtP4pXL6WZfRv pZj7Yd/Mr37NhOoZ5/yRgYooRlWPs15hvlbVjoetZx718N9BhvWhq5nGZ2xe3q69Mn7k=; Received: from sea.source.kernel.org ([172.234.252.31]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLS1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.95) id 1viy6l-0003zh-3q; Thu, 22 Jan 2026 17:04:35 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 528AE4099B; Thu, 22 Jan 2026 17:04:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 156DAC116C6; Thu, 22 Jan 2026 17:04:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1769101464; bh=xwFz5Oidq8APQpCp7THEtDpXn9O+NGssd7GC7NPkIXE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ueyMX6ohlT+V7E4FTnwyr+bckr2XgM0otlsgh+U8+RB7dufNou2jXtRF8/4HiLX1h aiyHG+xAbRXlOpSKYNl+YW1B6es8lJGWyDpCT3G89X8Bn++QSMPHsovt5BRyWj7Z84 MiFPflUjkr2UeHtVIt004pQ2LHYESJ6jR9ib6bF3tKB5BvchCfBJcHtl2H7eGV6Hj+ XeQh59i2mPbJ0Z07CURTocG8MzgcrhLB0YpqMQ2BX+Q2rUwcSwiRIRCTHIiyBghAen fRki137MnL3p5j+2P7Cc4giyKdLsB0k8xoBASjwbPFk1rE23p0Kg5qRxi8CJQxSLFn VC/vMBqCcUNNQ== Date: Thu, 22 Jan 2026 09:04:23 -0800 To: Jeff Layton Message-ID: <20260122170423.GU5945@frogsfrogsfrogs> References: <176885553525.16766.291581709413217562@noble.neil.brown.name> <176890126683.16766.5241619788613840985@noble.neil.brown.name> <176899164457.16766.16099772451425825775@noble.neil.brown.name> <364d2fd98af52a2e2c32ca286decbdc1fe1c80d3.camel@kernel.org> <3210d04fa2c0b1f4312d10506cac30586cb49a3c.camel@kernel.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Headers-End: 1viy6l-0003zh-3q 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: "Darrick J. Wong via Linux-f2fs-devel" Reply-To: "Darrick J. Wong" 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 , NeilBrown , 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 , linux-nfs@vger.kernel.org, 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, Christian Brauner , Theodore Ts'o , Luis de Bethencourt , Joseph Qi , linux-erofs@lists.ozlabs.org, 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 Thu, Jan 22, 2026 at 07:12:36AM -0500, Jeff Layton wrote: > On Wed, 2026-01-21 at 22:37 -0800, Christoph Hellwig wrote: > > On Wed, Jan 21, 2026 at 10:18:00AM -0500, Jeff Layton wrote: > > > > fat seems to be an exception as far as the 'real' file systems go. > > > > And it did sound to me like some of the synthetic ones had similar > > > > issues. > > > > > > > > > > Not sure what we can do about FAT without changing the filehandle > > > format in some fashion. The export ops just use > > > generic_encode_ino32_fh, and FAT doesn't have stable inode numbers. > > > The "nostale" ops seem sane enough but it looks like they only work > > > with the fs in r/o mode. > > > > Yeah. I guess we need to ignore this because of > > > > Yep. This is a case where the handles are not PERSISTENT but I don't > think we can get away with making FAT unexportable. We're probably > stuck with it. > > > > > I think Amirs patch would take care of that. Although userland nfs > > > > servers or other storage applications using the handle syscalls would > > > > still see them. Then again fixing the problem that some handles > > > > did not fulfill the long standing (but not documented well enough) > > > > semantics probably is a good fix on it's own. > > > > > > Agreed. We should try to ensure uniqueness and persistence in all > > > filehandles both for nfsd and userland applications. > > > > Sounds good to me. > > > Unfortunately, there are already exceptions. Apparently pidfs and > cgroupfs handles (at least) can't be extended because of userspace > expectations: > > https://lore.kernel.org/linux-nfs/20260120-irrelevant-zeilen-b3c40a8e6c30@brauner/ systemd cracking file handles?? Yeesh, I thought userspace was supposed to treat a file handle as an opaque N-byte blob and nothing more, and only certain "special" tools (e.g. xfsprogs on XFS) could do more than that. --D > My personal take is that we should try to make handle uniqueness a goal > for most existing filesystems, but we're going to have some that can't > achieve that. For them we probably want to be able to flag them so they > can be id'ed by userland. > > So, we will need an export_operations flag of some sort > (EXPORT_OP_UNIQUE_HANDLES?). At that point, we'll have to decide > whether to deny nfsd export based on that flag: > > We could deny export of any fs that doesn't set the flag, but NFSv4 > actually allows the server to advertise that it can't guarantee handle > uniqueness. There isn't much guidance for the client on how to handle > that though and the attribute seems to have the scope of the entire NFS > server. > > -- > Jeff Layton > _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel