[LTP] [PATCH v4, 2/2] cgroup/cgroup_regression_test: Fix umount failure

[Petr Vorel <pvorel@suse.cz>]

Hi,

FYI this discussion is on v4, there is already v5 (marking it changes requested
in patchwork) and obviously v6 will be needed. Leo, I suppose you'll implement
everything mentioned here in v6.

> Hi!
> > I had a first look at this patches and was curious, what the reasoning 
> > behind the "/" is.
+1 I should have ask myself as well :).

> > The comment you suggest is wrong. The / was introduced to prevent 
> > unmounting some other mountpoint,
> > where the device was cgroup.
> > Imho the approach of adding a / to the end was wrong and intransparent. 
> > I would rather use "./cgroup" or "$PWD/cgroup".

> Passing full path to the cgroup directory sound much safer to me
> especially when the directory name is just 'cgroup', try it yourself:

> device=cgroup/; grep "${device%/}" /proc/mounts

> On my machine this yields 10 lines and 21 matches.

> > If possible, I'd actually change tst_umount, to always unmount the 
> > mountpoint and not the device, i.e. if the given path is not an absolute 
> > path, make it absolute (e.g. by prepending $PWD").
> > This way the check if the mountpoint exist wouldn't be the fuzzy thing 
> > it is right now.
+1

> Strongly agree here.

> I would go even one step further and change the library so that it
> rejects anything that does not start with '/'.
+1

Kind regards,
Petr