linux-ext4 - Re: [PATCH 01/29] exportfs: add new EXPORT_OP_STABLE

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <6bajjyslarqrjr2brzyy6bgrmqrdxyhc42q7pfmz42d4y4kjtn@fod6fi4uf6qv>
Date: Fri, 16 Jan 2026 11:45:55 +0100
From: Jan Kara <jack@...e.cz>
To: Jeff Layton <jlayton@...nel.org>
Cc: Christian Brauner <brauner@...nel.org>, 
	Alexander Viro <viro@...iv.linux.org.uk>, Chuck Lever <chuck.lever@...cle.com>, 
	NeilBrown <neil@...wn.name>, Olga Kornievskaia <okorniev@...hat.com>, 
	Dai Ngo <Dai.Ngo@...cle.com>, Tom Talpey <tom@...pey.com>, Amir Goldstein <amir73il@...il.com>, 
	Hugh Dickins <hughd@...gle.com>, Baolin Wang <baolin.wang@...ux.alibaba.com>, 
	Andrew Morton <akpm@...ux-foundation.org>, Theodore Ts'o <tytso@....edu>, 
	Andreas Dilger <adilger.kernel@...ger.ca>, Jan Kara <jack@...e.com>, Gao Xiang <xiang@...nel.org>, 
	Chao Yu <chao@...nel.org>, Yue Hu <zbestahu@...il.com>, 
	Jeffle Xu <jefflexu@...ux.alibaba.com>, Sandeep Dhavale <dhavale@...gle.com>, 
	Hongbo Li <lihongbo22@...wei.com>, Chunhai Guo <guochunhai@...o.com>, 
	Carlos Maiolino <cem@...nel.org>, Ilya Dryomov <idryomov@...il.com>, 
	Alex Markuze <amarkuze@...hat.com>, Viacheslav Dubeyko <slava@...eyko.com>, Chris Mason <clm@...com>, 
	David Sterba <dsterba@...e.com>, Luis de Bethencourt <luisbg@...nel.org>, 
	Salah Triki <salah.triki@...il.com>, Phillip Lougher <phillip@...ashfs.org.uk>, 
	Steve French <sfrench@...ba.org>, Paulo Alcantara <pc@...guebit.org>, 
	Ronnie Sahlberg <ronniesahlberg@...il.com>, Shyam Prasad N <sprasad@...rosoft.com>, 
	Bharath SM <bharathsm@...rosoft.com>, Miklos Szeredi <miklos@...redi.hu>, 
	Mike Marshall <hubcap@...ibond.com>, Martin Brandenburg <martin@...ibond.com>, 
	Mark Fasheh <mark@...heh.com>, Joel Becker <jlbec@...lplan.org>, 
	Joseph Qi <joseph.qi@...ux.alibaba.com>, Konstantin Komarov <almaz.alexandrovich@...agon-software.com>, 
	Ryusuke Konishi <konishi.ryusuke@...il.com>, Trond Myklebust <trondmy@...nel.org>, 
	Anna Schumaker <anna@...nel.org>, Dave Kleikamp <shaggy@...nel.org>, 
	David Woodhouse <dwmw2@...radead.org>, Richard Weinberger <richard@....at>, Jan Kara <jack@...e.cz>, 
	Andreas Gruenbacher <agruenba@...hat.com>, OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>, 
	Jaegeuk Kim <jaegeuk@...nel.org>, Christoph Hellwig <hch@...radead.org>, linux-nfs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org, linux-mm@...ck.org, 
	linux-ext4@...r.kernel.org, linux-erofs@...ts.ozlabs.org, linux-xfs@...r.kernel.org, 
	ceph-devel@...r.kernel.org, linux-btrfs@...r.kernel.org, linux-cifs@...r.kernel.org, 
	samba-technical@...ts.samba.org, linux-unionfs@...r.kernel.org, devel@...ts.orangefs.org, 
	ocfs2-devel@...ts.linux.dev, ntfs3@...ts.linux.dev, linux-nilfs@...r.kernel.org, 
	jfs-discussion@...ts.sourceforge.net, linux-mtd@...ts.infradead.org, gfs2@...ts.linux.dev, 
	linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [PATCH 01/29] exportfs: add new EXPORT_OP_STABLE_HANDLES flag

On Thu 15-01-26 12:47:32, Jeff Layton wrote:
> At one time, nfsd could take the presence of struct export_operations to
> be an indicator that a filesystem was exportable via NFS. Since then, a
> lot of filesystems have grown export operations in order to provide
> filehandle support. Some of those (e.g. kernfs, pidfs, and nsfs) are not
> suitable for export via NFS since they lack filehandles that are
> stable across reboot.
> 
> Add a new EXPORT_OP_STABLE_HANDLES flag that indicates that the
> filesystem supports perisistent filehandles, a requirement for nfs
> export. While in there, switch to the BIT() macro for defining these
> flags.
> 
> For now, the flag is not checked anywhere. That will come later after
> we've added it to the existing filesystems that need to remain
> exportable.
> 
> Signed-off-by: Jeff Layton <jlayton@...nel.org>

...

> -#define EXPORT_OP_FLUSH_ON_CLOSE	(0x20) /* fs flushes file data on close */
> -#define EXPORT_OP_NOLOCKS		(0x40) /* no file locking support */
> +#define EXPORT_OP_FLUSH_ON_CLOSE	BIT(5) /* fs flushes file data on close */
> +#define EXPORT_OP_NOLOCKS		BIT(6) /* no file locking support */
> +#define EXPORT_OP_STABLE_HANDLES	BIT(7) /* required for nfsd export */

The comment "required for nfsd export" doesn't quite match the name. I'd
change the comment to something like "file handles are stable across
reboot". Otherwise feel free to add:

Reviewed-by: Jan Kara <jack@...e.cz>

								Honza
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR