Re: [PATCH 2/2] vfs: dedupe should return EPERM if permission is not granted

[Mark Fasheh <mfasheh@suse.de>]

On Fri, May 11, 2018 at 05:06:34PM -0700, Darrick J. Wong wrote:
> On Fri, May 11, 2018 at 12:26:51PM -0700, Mark Fasheh wrote:
> > Right now we return EINVAL if a process does not have permission to dedupe a
> > file. This was an oversight on my part. EPERM gives a true description of
> > the nature of our error, and EINVAL is already used for the case that the
> > filesystem does not support dedupe.
> > 
> > Signed-off-by: Mark Fasheh <mfasheh@suse.de>
> > ---
> >  fs/read_write.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/fs/read_write.c b/fs/read_write.c
> > index 77986a2e2a3b..8edef43a182c 100644
> > --- a/fs/read_write.c
> > +++ b/fs/read_write.c
> > @@ -2038,7 +2038,7 @@ int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
> >  			info->status = -EINVAL;
> >  		} else if (!(is_admin || (dst_file->f_mode & FMODE_WRITE) ||
> >  			     uid_eq(current_fsuid(), dst->i_uid))) {
> > -			info->status = -EINVAL;
> > +			info->status = -EPERM;
> 
> Hmm, are we allowed to change this aspect of the kabi after the fact?
> 
> Granted, we're only trading one error code for another, but will the
> existing users of this care?  xfs_io won't and I assume duperemove won't
> either, but what about bees? :)

Yeah if you see my initial e-mail I check bees and also rust-btrfs. I think
this is fine as we're simply expanding on an error code return. There's no
magic behavior expected with respect to these error codes either.
	--Mark