Re: noatime on ufs2

Am 2024-01-30 01:21, schrieb Warner Losh:

> On Mon, Jan 29, 2024 at 2:31 PM Olivier Certner <olce@freebsd.org> 
> wrote:

>>> It also seems undesirable to add a sysctl to control a value that the
>>> kernel doesn't use.
>> 
>> The kernel has to use it to guarantee some uniform behavior 
>> irrespective of the mount being performed through mount(8) or by a 
>> direct call to nmount(2).  I think this consistency is important.  
>> Perhaps all auto-mounters and mount helpers always run mount(8) and 
>> never deal with nmount(2), I would have to check (I seem to remember 
>> that, a long time ago, when nmount(2) was introduced as an enhancement 
>> over mount(2), the stance was that applications should use mount(8) 
>> and not nmount(2) directly).  Even if there were no obvious callers of 
>> nmount(2), I would be a bit uncomfortable with this discrepancy in 
>> behavior.
> 
> I disagree. I think Mike's suggestion was better and dealt with POLA 
> and POLA breaking in a sane way. If the default is applied universally 
> in user space, then we need not change the kernel at all. We lose all 
> the chicken and egg problems and the non-linearness of the sysctl idea.

I would like to add that a sysctl is some kind of a hidden setting, 
whereas /etc/fstab + /etc/defaults/fstab is a "right in the face" way of 
setting filesystem / mount related stuff.

[...]

> It could also be generalized so that the FSTYPE could have different 
> settings for different types of filesystem (maybe unique flags that 
> some file systems don't understand).

+1

nosuid for tmpfs comes into my mind here...

> One could also put it in /etc/defaults/fstab too and not break POLA 
> since that's the pattern we use elsewhere.

+1

> Anyway, I've said my piece. I agree with Mike that there's consensus 
> for this from the installer, and after that consensus falls away. 
> Mike's idea is one that I can get behind since it elegantly solves the 
> general problem.

+1

Bye,
Alexander.

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