Re: [PATCH] libmount: provide tree fd even when a mount helper is used

[Karel Zak <kzak@redhat.com>]

On Thu, May 30, 2024 at 08:00:34PM +0200, Linus Heckemann wrote:
> Previously, the X-mount.subdir option would fail (mount exited with
> code 0, but the target was not mounted) when a helper was used.

Do you have any examples that can easily reproduce it?

> In addition to fixing X-mount.subdir, this allows dropping the
> fallback behaviour previously implemented specifically by the
> set_vfsflags and set_propagation hooks.
> 
> I realise this patch is not acceptable as is, since I just exported
> the previously private open_mount_tree symbol from hook_mount.c

Perhaps it is unnecessary to only keep the API file descriptors in
hook_mount.c. It is a generic feature and we may see more use
cases where it would make sense to use it in other places.

I can imagine having the file descriptors in the libmnt_context
structure and initializing them through functions in context.c (which
would involve renaming open_mount_tree() to something more
appropriate). It could potentially be a public library function so
that libmount applications can also utilize it.

I will think about it :-)

    Karel

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