Re: [PATCH v3 3/3] fs: store real path instead of fake path in backing file f_path

[Miklos Szeredi <miklos@xxxxxxxxxx>]

On Mon, 9 Oct 2023 at 17:37, Amir Goldstein <amir73il@xxxxxxxxx> wrote:

>  static inline void put_file_access(struct file *file)
> diff --git a/fs/open.c b/fs/open.c
> index fe63e236da22..02dc608d40d8 100644
> --- a/fs/open.c
> +++ b/fs/open.c
> @@ -881,7 +881,7 @@ static inline int file_get_write_access(struct file *f)
>         if (unlikely(error))
>                 goto cleanup_inode;
>         if (unlikely(f->f_mode & FMODE_BACKING)) {
> -               error = mnt_get_write_access(backing_file_real_path(f)->mnt);
> +               error = mnt_get_write_access(backing_file_user_path(f)->mnt);
>                 if (unlikely(error))
>                         goto cleanup_mnt;
>         }

Do we really need write access on the overlay mount?

If so, should the order of getting write access not be the other way
round (overlay first, backing second)?

Thanks,
Miklos