Re: [PATCH AUTOSEL 6.11 48/76] fuse: allow O_PATH fd for FUSE_DEV_IOC_BACKING_OPEN

[Sasha Levin]

On Mon, Oct 07, 2024 at 12:15:45PM +0200, Miklos Szeredi wrote:
> On Fri, 4 Oct 2024 at 20:19, Sasha Levin <sashal@xxxxxxxxxx> wrote:
> > From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
> >
> > [ Upstream commit efad7153bf93db8565128f7567aab1d23e221098 ]
> >
> > Only f_path is used from backing files registered with
> > FUSE_DEV_IOC_BACKING_OPEN, so it makes sense to allow O_PATH descriptors.
> >
> > O_PATH files have an empty f_op, so don't check read_iter/write_iter.
> >
> > Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
> > Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> > ---
> >  fs/fuse/passthrough.c | 7 ++-----
> >  1 file changed, 2 insertions(+), 5 deletions(-)
> >
> > diff --git a/fs/fuse/passthrough.c b/fs/fuse/passthrough.c
> > index 9666d13884ce5..62aee8289d110 100644
> > --- a/fs/fuse/passthrough.c
> > +++ b/fs/fuse/passthrough.c
> > @@ -228,16 +228,13 @@ int fuse_backing_open(struct fuse_conn *fc, struct fuse_backing_map *map)
> >         if (map->flags || map->padding)
> >                 goto out;
> >
> > -       file = fget(map->fd);
> > +       file = fget_raw(map->fd);
> >         res = -EBADF;
> >         if (!file)
> >                 goto out;
> >
> > -       res = -EOPNOTSUPP;
> > -       if (!file->f_op->read_iter || !file->f_op->write_iter)
> > -               goto out_fput;
> > -
> >         backing_sb = file_inode(file)->i_sb;
> > +       pr_info("%s: %x:%pD %i\n", __func__, backing_sb->s_dev, file, backing_sb->s_stack_depth);
>
> That's a stray debug line that wasn't in there when I posted the patch
> for review[1], but somehow made it into the pull...
>
> Since this isn't a bug fix, it would be easiest to just drop the patch
> from the stable queues.
>
> But I'm okay with just dropping this stray line from the backport, or
> waiting for an upstream fix which does that.

I'll just drop it, thanks!

--
Thanks,
Sasha