Re: [util-linux PATCH] umount: never 'stat' the path when "-c" is given.

[Karel Zak <kzak@redhat.com>]

On Wed, Jun 07, 2017 at 11:44:51AM +0200, Karel Zak wrote:
> On Mon, Jun 05, 2017 at 12:32:58PM +1000, NeilBrown wrote:
> > diff --git a/libmount/src/context_umount.c b/libmount/src/context_umount.c
> > index e663a703cca0..693891def0e1 100644
> > --- a/libmount/src/context_umount.c
> > +++ b/libmount/src/context_umount.c
> > @@ -77,6 +77,7 @@ int mnt_context_find_umount_fs(struct libmnt_context *cxt,
> >  	 * it's usable only for canonicalized stuff (e.g. kernel mountinfo).
> >  	 */
> >  	if (!mnt_context_mtab_writable(cxt) && *tgt == '/' &&
> > +	    !mnt_context_is_nocanonicalize(cxt) &&
> >  	    !mnt_context_is_force(cxt) && !mnt_context_is_lazy(cxt))
> >  		rc = mnt_context_get_mtab_for_target(cxt, &mtab, tgt);
> 
> I've changed the code to be the mount table filter also usable for
> --no-canonicalize. It seems better to avoid mnt_resolve_path() than
> avoid all the filter.

Hmm... the filter seems like bad optimization for umount, because it
triggers path canonicalization. I did some another changes and umount
should be less aggressive with work with paths now.

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com