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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=haSfZvoEvPhBBZDnUW3y3BhJEQ36mgFSvpNiOqhvJvI=; b=N18Lfx2l0cTzfa3HEHbSStwRPv iyXHar7+IL8UusFL6sjIudxhuirPKAhJMeBNA+7JTaSgRPwHzsN72C9/ED13gd4R3bzZoK6cN15el 2OOL3ox9rvwKCy+jqAl20MM1KOQeI06m0Nqc7qZlyinWokSDH6OADy7uwk70GRUXw1dKPRbjqr1Mx G0x+S1U8gEmAS0uHHMxQqMK+KDGwlJXyI4/nRqaD3y/MPBEQbIe1RJKnMGnpCsJCrYQkezP6l13YD Bk/y5So46wc2umpZT0PCIQ7tT9Ms4VQ/Y3zVPPZ8bLDLhE9SURfv9f85/RpFqttM9TA+n04nUeD09 UJSC4XRw==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vi6VB-00000003NIK-3jXc; Tue, 20 Jan 2026 07:50:15 +0000 Date: Mon, 19 Jan 2026 23:50:13 -0800 From: Christoph Hellwig To: Jeff Layton 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 , Christoph Hellwig , 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 Subject: Re: [PATCH v2 02/31] exportfs: add new EXPORT_OP_STABLE_HANDLES flag Message-ID: References: <20260119-exportfs-nfsd-v2-0-d93368f903bd@kernel.org> <20260119-exportfs-nfsd-v2-2-d93368f903bd@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; 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See http://www.infradead.org/rpr.html X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 333FEC0006 X-Rspam-User: X-Stat-Signature: 1zt9yqs8m13qxdzm58xeoypgfs188epa X-HE-Tag: 1768895434-202126 X-HE-Meta: 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 HqZKSisL 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 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, Jan 19, 2026 at 11:26:19AM -0500, Jeff Layton wrote: > + EXPORT_OP_STABLE_HANDLES - This filesystem provides filehandles that are > + stable across the lifetime of a file. This is a hard requirement for export > + via nfsd. Any filesystem that is eligible to be exported via nfsd must > + indicate this guarantee by setting this flag. Most disk-based filesystems > + can do this naturally. Pseudofilesystems that are for local reporting and > + control (e.g. kernfs, pidfs, nsfs) usually can't support this. Suggested rewording, taking some of the ideas from Dave Chinners earlier comments into account: EXPORT_OP_STABLE_HANDLES - This filesystem provides filehandles that are stable across the lifetime of a file. A file in this context is an instantiated inode reachable by one or more file names, or still open after the last name has been unlinked. Reuses of the same on-disk inode structure are considered new files and must provide different file handles from the previous incarnation. Most file systems designed to store user data naturally provide this capability. Pseudofilesystems that are for local reporting and control (e.g. kernfs, pidfs, nsfs) usually can't support this. This flags is a hard requirement for export via nfsd. Any filesystem that is eligible to be exported via nfsd must indicate this guarantee by setting this flag.