Re: Vanishing GPT/UFS labels

Warner Losh <[email protected]> writes:

> On Thu, May 21, 2026 at 6:46 AM Stéphane Rochoy <[email protected]> wrote:
>  …
>  When I mount using the underlying device, /dev/${md}p2, both
>  /dev/gpt/bar and /dev/ufs/bar vanish. And when I umount (using the mount
>  point) both are back.
>
>  When I mount using the UFS label, /dev/ufs/bar, only /dev/gpt/bar
>  vanish. And when I umount the GPT label don't come back.
>
>  GEOM don't seems to agree with itself: `gpart show -l $md` do confirm both
>  partitions kept their GPT label but `glabel status` don't:
>
>      $ gpart show -l $md
>      =>    40  204720  md0  GPT  (100M)
>            40   20480    1  foo  (10M)
>         20520  184240    2  bar  (90M)
>      $ glabel status | grep -e foo -e bar
>           gpt/foo     N/A  md0p1
>           ufs/bar     N/A  md0p2
>
>  I would be happy to hunt what looks like bugs to me but I need some
>  insight first: what is the rationale behind the idea to remove a device
>  on mount and, possibly, restore it on umount?
>
> This sounds like the intentional behavior of geom to withdraw the
> devices when aliases are mounted.

So what I observe when mounting/umounting via the underlying device
(/dev/${md}p2) is the expected behavior.

But there's some problems when mounting/umounting via the UFS label
(/dev/ufs/bar):
- on mount, /dev/ufs/bar should vanish too
- and on umount /dev/gpt/bar should come back.

Regards,

Stéphane