Re: [PATCH 2/2] locks: set fl_owner for leases back to current->files

[Jeff Layton <jlayton@poochiereds.net>]

On Tue, 10 Jun 2014 16:53:43 -0400
"J. Bruce Fields" <bfields@fieldses.org> wrote:

> On Tue, Jun 10, 2014 at 04:14:36PM -0400, Jeff Layton wrote:
> > This fixes a regression due to commit 130d1f956ab3. I had mistakenly
> > thought that the fl_owner wasn't used in the lease code, but I missed
> > the place in __break_lease that does use it.
> > 
> > The i_have_this_lease check in generic_add_lease uses it. While I'm not
> > sure that check is terribly helpful [1], reset it back to using
> > current->files in order to ensure that there's no behavior change here.
> > 
> > [1]: leases are owned by the file description. It's possible that this
> >      is a threaded program, and the lease breaker and the task that
> >      would handle the signal are different, even if they have the same
> >      file table. So, there is the potential for false positives with
> >      this check.
> 
> ACK to restoring the old behavior, but meanwhile I'm pretty confused by
> the old behavior.
> 

Same here. Until we can untangle the history, it's probably best to not
change anything. I suspect that it might be best to just get rid of
that check, but it predates git so it might take some digging to
understand the original rationale.

> > Fixes:
> 
> Did you mean to have a 130d1f956ab3 there?
> 

Yes, thanks. Fixed in my tree...

> --b.
> 
> > Signed-off-by: Jeff Layton <jlayton@primarydata.com>
> > ---
> >  fs/locks.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/fs/locks.c b/fs/locks.c
> > index da57c9b7e844..717fbc404e6b 100644
> > --- a/fs/locks.c
> > +++ b/fs/locks.c
> > @@ -431,7 +431,7 @@ static int lease_init(struct file *filp, long type, struct file_lock *fl)
> >  	if (assign_type(fl, type) != 0)
> >  		return -EINVAL;
> >  
> > -	fl->fl_owner = (fl_owner_t)filp;
> > +	fl->fl_owner = (fl_owner_t)current->files;
> >  	fl->fl_pid = current->tgid;
> >  
> >  	fl->fl_file = filp;
> > -- 
> > 1.9.3
> > 


-- 
Jeff Layton <jlayton@poochiereds.net>