svn commit: r233048 - head/etc/defaults

[Martin Matuska]

On 19. 3. 2012 9:42, Alexander Leidinger wrote:
>>> The only disclosed information I know of is whether the zfs module is
>>> loaded on your system.
>>> Other alternative I was thinking of would be using a new ruleset (e.g.
>>> devfsrules_jail_zfs=5).
>>> The disadvantage here is that users that already have defined a ruleset
>>> with this number should be informed somehow.
>
> Well... we always have this issue. If the rulsets in defaults changes,
> the user has to change his own rulesets. I have a lot of rules on my
> system and there was at least one occasion where I had to handle a
> change because of this. I don't remember if there was an entry in
> UPDATING or not, but I don't think we should make a decission about it
> based upon if an user has to renumber his rulesets or not. As the
> rulesets do not need to be continous, we may want to add an advise to
> the man-page(s) to start at a specifc value for the ruleset-numbers
> and reserve everything below for the system. I didn't do this myself,
> and I have a lot of rulesets, for me this falls within 'nice to have
> but easy to handle'.
>
>> Btw. jail has access to sysctl(8) and this discloses a *LOT* of
>> information, including if ZFS is loaded or not (existence of vfs.zfs)
>> and all its settings and statistics, hardware devices, geom devices,
>> network card counters and many more. Compared to this is /dev/zfs really
>> a minor issue :-)
>
> I agree.
>
>> Until we limit the output of sysctl() we don't hide this information
>> just by hiding /dev/zfs.
>
> What about not imported pools. Can I see them in jails or are they
> hidden (I don't have one around to test ATM)? 
Until you delegate a zfs dataset to a jail, the jail does not see any
pools or datasets.

If you delegate a dataset to a jail, the jail sees information about the
delegated dataset, the dataset's pool, the parent datasets of this
delegated dataset (=the path from pool up to the delegated dataset) and
the descendant datasets, if any.

We might want to continue this discussion outside of the svn-src mailing
lists.

-- 
Martin Matuska
FreeBSD committer
http://blog.vx.sk