Re: [PATCH 0/4] Add the ability to query mount options in statmount

[Jeff Layton <jlayton@kernel.org>]

On Mon, 2024-06-24 at 15:40 -0400, Josef Bacik wrote:
> Hello,
> 
> Currently if you want to get mount options for a mount and you're
> using
> statmount(), you still have to open /proc/mounts to parse the mount
> options.
> statmount() does have the ability to store an arbitrary string
> however,
> additionally the way we do that is with a seq_file, which is also how
> we use
> ->show_options for the individual file systems.
> 
> Extent statmount() to have a flag for fetching the mount options of a
> mount.
> This allows users to not have to parse /proc mount for anything
> related to a
> mount.  I've extended the existing statmount() test to validate this
> feature
> works as expected.  As you can tell from the ridiculous amount of
> silly string
> parsing, this is a huge win for users and climate change as we will
> no longer
> have to waste several cycles parsing strings anymore.
> 
> This is based on my branch that extends listmount/statmount to walk
> into foreign
> namespaces.  Below are links to that posting, that branch, and this
> branch to
> make it easier to review.
> 
> https://lore.kernel.org/linux-fsdevel/cover.1719243756.git.josef@toxicpanda.com/
> https://github.com/josefbacik/linux/tree/listmount.combined
> https://github.com/josefbacik/linux/tree/statmount-opts
> 
> Thanks,
> 
> Josef
> 
> Josef Bacik (4):
>   fs: rename show_mnt_opts -> show_vfsmnt_opts
>   fs: add a helper to show all the options for a mount
>   fs: export mount options via statmount()
>   sefltests: extend the statmount test for mount options
> 
>  fs/internal.h                                 |   5 +
>  fs/namespace.c                                |   7 +
>  fs/proc_namespace.c                           |  29 ++--
>  include/uapi/linux/mount.h                    |   3 +-
>  .../filesystems/statmount/statmount_test.c    | 131
> +++++++++++++++++-
>  5 files changed, 164 insertions(+), 11 deletions(-)
> 

Nice work. I especially like that there is a selftest now.

Reviewed-by: Jeff Layton <jlayton@kernel.org>