Re: Removal of GEOM_BSD, GEOM_MBR, GEOM_PC98 and GEOM_SUNLABEL

On Saturday 04 April 2009 12:09:55 pm Marcel Moolenaar wrote:
> 
> On Apr 4, 2009, at 8:16 AM, Tai-hwa Liang wrote:
> 
> >  I have to use ad0s7 after moving to GEOM_PART_{BSD,EBR,MBR};  
> > otherwise,
> > booting with with /dev/ad0s7a looks like:
> 
> > Can't stat /dev/ad0s7a: No such file or directory
> 
> It just hit me (doh!). The problem is that /dev/ad0s7 is a
> compatibility symlink, which exists outside of the GEOM
> graph. That is, it's a symlink that geom_dev creates and
> it provides an alternate name to the same "entry point".
> 
> In your case another GEOM (gpart for the BSD scheme) is
> stacked onto the gpart GEOM for the EBR scheme) -- with
> possibly other GEOMs in between. The provider for the 'a'
> partition is named based on the underlying consumer, which
> is based on the true name of the GEOM: "ad0s3+00103bf1a".
> 
> There's no alias for the device node that corresponds to
> this GEOM and based on some alias that was created by some
> other geom_dev. This is simply not possible to without
> messing things up pretty easily.
> 
> In short: the solution of using a compatibility symlink is
> flawed at best and useless in the worst case.
> 
> There's no software fix for it. I think we're left with a
> simple choice:
> 1) have EBR create the "old" names and tell the user to
>     reboot every time they make a change in FreeBSD and when
>     booting into FreeBSD after the EBR changed, boot into
>     single user mode to change /etc/fstab and *then* go into
>     multi-user mode, or
> 2) stick with the new names and tell the user to make this
>     one-time adjustment during upgrades and that's it.
> 
> If we choose 2, we can argue whether to keep the symlinks
> or not. I'm sure there's a small group of people for which
> it works, but I fear the majority of people still have
> problems.

I think it is less painful for folks upgrading from 7 to just use the old 
names.  It is also a lot easier on the eyes.  I'm also not sure people are 
going to be changing their partition layout once it is done so having the 
names 'change' would not seem to be something that would happen very often at 
all in practice.

-- 
John Baldwin