Re: [PATCH] ovl: fix wrong detection of 32bit inode numbers

On Tue, 24 Mar 2026 at 16:22, Amir Goldstein <[email protected]> wrote:
>
> The implicit FILEID_INO32_GEN encoder was changed to be explicit,
> so we need to fix the detection.
>
> When mounting overlayfs with upperdir and lowerdir on different ext4
> filesystems, the expected kmsg log is:
>
>   overlayfs: "xino" feature enabled using 32 upper inode bits.
>
> But instead, since the regressing commit, the kmsg log was:
>
>   overlayfs: "xino" feature enabled using 2 upper inode bits.
>
> Fixes: e21fc2038c1b9 ("exportfs: make ->encode_fh() a mandatory method for NFS export")
> Cc: [email protected] # v6.7+
> Signed-off-by: Amir Goldstein <[email protected]>
> ---
>
> Miklos,
>
> I have queued up this fix.
> The regression has no serious impact on most users, because xino
> works pretty well either way.
>
> A nested overlayfs, where the lower overlayfs is nonsamefs ext4
> would have less xino overflows, but this is a very corner case.

LGTM, thanks.

Miklos