[PATCH 1/8] kernfs: Add API to generate relative kernfs path

Serge E. Hallyn serge.hallyn at ubuntu.com
Mon Nov 30 18:37:58 UTC 2015


On Mon, Nov 30, 2015 at 10:11:47AM -0500, Tejun Heo wrote:
> Hello,
> 
> On Thu, Nov 26, 2015 at 11:25:11PM -0600, Serge E. Hallyn wrote:
> > > > +	/* Short-circuit the easy case - kn_to is the root node. */
> > > > +	if ((kn_from == kn_to) || (!kn_from && !kn_to->parent)) {
> > > > +		*p = '/';
> > > > +		*(p + 1) = '\0';
> > > 
> > > Hmm... so if kn_from == kn_to, the output is "/"?
> > 
> > Yes, that's what seems to make the most sense for cgroup namespaces.  I
> > could see a case for '.' being used instead in general, but for cgroup
> > namespaces I think we'd have to convert those back to '/'.  Otherwise
> > we'll fail in being able to run legacy software, which would get
> > confused.
> 
> Yeah, I agree but the name is kinda misleading tho.  The output isn't
> really a relative path but rather absolute path against the specified
> root.  Maybe updating the function and parameter names would be
> helpful?
> 
> Thanks.

Ok - updating the comment is simple enough.  Though the name/params
kernfs_path_from_node_locked(from, to) still seem to make sense.  Would
you prefer something like kernfs_absolute_path_from node_locked()?  I
hesitate to call 'from' 'root' since kernfs_root is a thing and this
is not that.



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