Re: ZFS property inheritance broken for `readonly`?

On Fri, May 03, 2024 at 05:39:26PM -0400, Garrett Wollman wrote:
> I've noticed recently (not sure when this started, maybe on the 12->13
> transition, which would be the same as the old ZFS to OpenZFS
> transition for us) that inheritance for the `readonly` property is
> broken.
> 
> Here is an example:
> 
> [root@nfs-prod-11 /home/wollman]# zfs set readonly=on export/cl
> [root@nfs-prod-11 /home/wollman]# zfs get readonly export/cl/u
> NAME         PROPERTY  VALUE   SOURCE
> export/cl/u  readonly  off     temporary
> 
> The child filesystem `export/cl/u` should have inherited the readonly
> setting from `export/cl` but instead it (and all other children) have
> overridden it, and I have to manually `zfs inherit readonly` on all of
> the children to get the proper behavior.  This is quite surprising,
> and the first time it happened I was sure that something had gone
> wrong.

I find myself wondering if ZFS was unable to downgrade the mount and
this is a transient state, but the fact that inherit works suggests
otherwise.  I suppose it could be a missing case in the spl layer.

-- Brooks