On Tue, Sep 10, 2019 at 10:35:09PM +0000, Yonghong Song wrote:
>
> Carlos,
>
> Discussed with Eric today for what is the best way to get
> the device number for a namespace. The following patch seems
> a reasonable start although Eric would like to see
> how the helper is used in order to decide whether the
> interface looks right.
>
> commit bb00fc36d5d263047a8bceb3e51e969d7fbce7db (HEAD -> fs2)
> Author: Yonghong Song <yhs@xxxxxx>
> Date: Mon Sep 9 21:50:51 2019 -0700
>
> nsfs: add an interface function ns_get_inum_dev()
>
> This patch added an interface function
> ns_get_inum_dev(). Given a ns_common structure,
> the function returns the inode and device
> numbers. The function will be used later
> by a newly added bpf helper.
>
> Signed-off-by: Yonghong Song <yhs@xxxxxx>
>
> diff --git a/fs/nsfs.c b/fs/nsfs.c
> index a0431642c6b5..a603c6fc3f54 100644
> --- a/fs/nsfs.c
> +++ b/fs/nsfs.c
> @@ -245,6 +245,14 @@ struct file *proc_ns_fget(int fd)
> return ERR_PTR(-EINVAL);
> }
>
> +/* Get the device number for the current task pidns.
> + */
> +void ns_get_inum_dev(struct ns_common *ns, u32 *inum, dev_t *dev)
> +{
> + *inum = ns->inum;
> + *dev = nsfs_mnt->mnt_sb->s_dev;
> +}
Umm... Where would it get the device number once we get (hell knows
what for) multiple nsfs instances? I still don't understand what
would that be about, TBH... Is it really per-userns? Or something
else entirely? Eric, could you give some context?
