From: Christoph Hellwig <hch@infradead.org>
To: Jan Kara <jack@suse.cz>
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Subject: Re: [f2fs-dev] [PATCH v2 02/31] exportfs: add new EXPORT_OP_STABLE_HANDLES flag
Date: Wed, 21 Jan 2026 01:17:14 -0800 [thread overview]
Message-ID: <aXCZmmBRSJR3ftHn@infradead.org> (raw)
In-Reply-To: <56fr33ju43h6zzp6jrzrkyfag6r3jz6wpnk45oe5byy6fqyvti@d43hgikfuk7t>
On Tue, Jan 20, 2026 at 09:40:07AM +0100, Jan Kara wrote:
> (with explanations before I couldn't quite see the difference between shmem
> and kernfs). I'd note that fat or shmem (which are both exportable)
> satisfy this only with reasonably high probability as they use
> get_random_u32() for initializing their i_generation but I guess it's as
> good as it gets for them.
For tmpfs random generations are as good as it gets, in fact that's what
XFS starts with when allocating new inode clusters (which could have
previous been used for for inodes as well).
fat on the other hand looks broken, as it also set a new generation when
reading inodes from disk. So I don't think fat should be nfs exportable,
even if the export ops predate other uses.
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next prev parent reply other threads:[~2026-01-21 9:18 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-19 16:26 [f2fs-dev] [PATCH v2 00/31] fs: require filesystems to explicitly opt-in to nfsd export support Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 01/31] Documentation: document EXPORT_OP_NOLOCKS Jeff Layton via Linux-f2fs-devel
2026-01-20 7:44 ` Christoph Hellwig
2026-01-20 13:20 ` Jeff Layton via Linux-f2fs-devel
2026-01-20 14:12 ` Jeff Layton via Linux-f2fs-devel
2026-01-20 14:35 ` Jeff Layton via Linux-f2fs-devel
2026-01-21 9:17 ` Christoph Hellwig
2026-01-21 9:58 ` NeilBrown
2026-01-21 12:29 ` Jeff Layton via Linux-f2fs-devel
2026-01-21 22:47 ` NeilBrown
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 02/31] exportfs: add new EXPORT_OP_STABLE_HANDLES flag Jeff Layton via Linux-f2fs-devel
2026-01-19 16:41 ` Amir Goldstein
2026-01-20 7:50 ` Christoph Hellwig
2026-01-20 8:40 ` Jan Kara
2026-01-21 9:17 ` Christoph Hellwig [this message]
2026-01-20 13:21 ` Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 03/31] tmpfs: add EXPORT_OP_STABLE_HANDLES flag to export operations Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 04/31] ext4: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 05/31] ext2: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 06/31] erofs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 07/31] efs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 08/31] xfs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 09/31] ceph: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 10/31] btrfs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 11/31] befs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 12/31] ufs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 13/31] udf: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 14/31] affs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 15/31] squashfs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 16/31] smb/client: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 17/31] ovl: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:42 ` Amir Goldstein
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 18/31] orangefs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 19/31] ocfs2: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 20/31] ntfs3: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 21/31] nilfs2: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 22/31] nfs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 23/31] jfs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 24/31] jffs2: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 25/31] isofs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 26/31] gfs2: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 27/31] fuse: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:43 ` Amir Goldstein
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 28/31] fat: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 29/31] f2fs: " Jeff Layton via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 30/31] nfsd: only allow filesystems that set EXPORT_OP_STABLE_HANDLES Jeff Layton via Linux-f2fs-devel
2026-01-19 16:51 ` Chuck Lever via Linux-f2fs-devel
2026-01-19 16:26 ` [f2fs-dev] [PATCH v2 31/31] nfsd: convert dprintks in check_export() to tracepoints Jeff Layton via Linux-f2fs-devel
2026-01-19 16:47 ` Chuck Lever via Linux-f2fs-devel
2026-01-20 13:42 ` Jeff Layton via Linux-f2fs-devel
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