Re: [PATCH] driver core: remove CONFIG_SYSFS_DEPRECATED

[Greg KH <gregkh@suse.de>]

On Wed, Jul 14, 2010 at 05:40:27PM -0700, Eric W. Biederman wrote:
> Andrew Morton <akpm@linux-foundation.org> writes:
> 
> > On Fri, 9 Jul 2010 11:54:50 -0700
> > Greg Kroah-Hartman <gregkh@suse.de> wrote:
> >
> >> This is no longer needed by any userspace tools, so it's safe to
> >> remove.
> >
> > Makes my FC6 test box not boot - can't find /dev/root.  Then when I go
> > back to plain old mainline (2.6.35-rc5) and run `make oldconfig', the
> > .config change sticks:
> >
> > @@ -106,8 +106,7 @@
> >  CONFIG_LOG_BUF_SHIFT=17
> >  CONFIG_HAVE_UNSTABLE_SCHED_CLOCK=y
> >  # CONFIG_CGROUPS is not set
> > -CONFIG_SYSFS_DEPRECATED=y
> > -CONFIG_SYSFS_DEPRECATED_V2=y
> > +# CONFIG_SYSFS_DEPRECATED_V2 is not set
> >  CONFIG_RELAY=y
> >  CONFIG_NAMESPACES=y
> >  # CONFIG_UTS_NS is not set
> >
> > and the box still won't boot.
> 
> The reason FC6 doesn't boot is there is a userspace tool
> I believe in the initrd that cares about symlinks when it should
> not.

Anyone happen to know which tool it is?  I remember we had had issues
with FC3 around this area, but I thought we resolved them, so it's
supprising to me that FC6 has issues.

> What is more interesting is that currently there is a bug in
> 2.6.35-rc5 where rmmod <netdriver> modprobe <netdriver> will in fact
> fail.  There was an inadvertent regression and no one has noticed or
> complained.  I spotted it by code review just a little bit ago and I
> haven't had a chance to write and test the fix yet.
> 
> If the code is going to start bitrotting and no one is going to
> notice or care simply removing the code instead of subjecting users
> to weird unexpected breakage seems like a responsible thing to do.

Yeah, that's what prompted this removal.  After the s390 guys said that
they were all good to go, I figured no one else would have problems with
it :)

If it turns out there still are issues with older userspaces like FC6
that we can't resolve, I have no problem dropping this patch and then we
will have to fix up the regression.

thanks,

greg k-h