Re: More duplicate code, vnode locking question

[Elad Efrat <elad%NetBSD.org@localhost>]

On Thu, Apr 23, 2009 at 12:42 AM, Antti Kantee <pooka%cs.hut.fi@localhost> 
wrote:

>>   - How does locking devvp violate the locking order of vnodes? (note
>>     that I'm not suggesting it doesn't)
>
> I wrote that in the previous email.  You always lock from root down.
> If you don't know the relationship of two vnodes, you cannot lock
> them both at the same time.  In this case you are already holding the
> mountpoint lock.
>
> Like I also wrote, the mount path locking is special because of recursive
> locks (which combined with namei already is a deadlock waiting to
> happen!).  No point in fussing around if you can't fix anything.
>
>>   - How do we weigh what is a more severe bug? :)
>
> i decide ;)

:)

For now I'll just focus on my original goal then, and it looks like
requiring that devvp is locked for genfs_can_mount() is okay, so I'll
just do that.

Thanks,

-e.