Re: [PATCH 16/29] ovl: add EXPORT_OP_STABLE_HANDLES flag to export operations

Amir Goldstein
2026-01-15T18:22:09Z

On Thu, Jan 15, 2026 at 6:49 PM Jeff Layton <jlayton@kernel.org> wrote:
>
> Add the EXPORT_OP_STABLE_HANDLES flag to overlayfs export operations to indicate
> that this filesystem can be exported via NFS.
>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
> fs/overlayfs/export.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
> index 83f80fdb156749e65a4ea0ab708cbff338dacdad..17c92a228120e1803135cc2b4fe4180f5e343f88 100644
> --- a/fs/overlayfs/export.c
> +++ b/fs/overlayfs/export.c
> @@ -865,9 +865,11 @@ const struct export_operations ovl_export_operations = {
> .fh_to_parent = ovl_fh_to_parent,
> .get_name = ovl_get_name,
> .get_parent = ovl_get_parent,
> + .flags = EXPORT_OP_STABLE_HANDLES,
> };
>
> /* encode_fh() encodes non-decodable file handles with nfs_export=off */
> const struct export_operations ovl_export_fid_operations = {
> .encode_fh = ovl_encode_fh,
> + .flags = EXPORT_OP_STABLE_HANDLES,
> };
>

Actually, see comment above:
/* encode_fh() encodes non-decodable file handles with nfs_export=off */

That's the variant of export_ops when overlayfs cannot be nfs exported
because its encoded file handles can change after copyup+reboot.

Thanks,
Amir.