From: Al Viro <viro@zeniv.linux.org.uk>
To: Yonghong Song <yhs@fb.com>
Cc: Carlos Antonio Neira Bustos <cneirabustos@gmail.com>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"ebiederm@xmission.com" <ebiederm@xmission.com>,
"brouer@redhat.com" <brouer@redhat.com>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>
Subject: Re: [PATCH bpf-next v10 2/4] bpf: new helper to obtain namespace data from current task New bpf helper bpf_get_current_pidns_info.
Date: Wed, 11 Sep 2019 00:15:06 +0100 [thread overview]
Message-ID: <20190910231506.GL1131@ZenIV.linux.org.uk> (raw)
In-Reply-To: <dadf3657-2648-14ef-35ee-e09efb2cdb3e@fb.com>
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@fb.com>
> 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@fb.com>
>
> 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?
next prev parent reply other threads:[~2019-09-10 23:15 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-06 15:09 [PATCH bpf-next v10 0/4] BPF: New helper to obtain namespace data from current task Carlos Neira
2019-09-06 15:09 ` [PATCH bpf-next v10 1/4] fs/namei.c: make available filename_lookup() for bpf helpers Carlos Neira
2019-09-06 15:09 ` [PATCH bpf-next v10 2/4] bpf: new helper to obtain namespace data from current task New bpf helper bpf_get_current_pidns_info Carlos Neira
2019-09-06 15:24 ` Al Viro
2019-09-06 15:46 ` Al Viro
2019-09-06 16:00 ` Al Viro
2019-09-06 23:21 ` Yonghong Song
2019-09-07 0:10 ` Al Viro
2019-09-07 6:34 ` Yonghong Song
2019-09-09 17:45 ` Carlos Antonio Neira Bustos
2019-09-10 22:35 ` Yonghong Song
2019-09-10 23:15 ` Al Viro [this message]
2019-09-11 8:16 ` Eric W. Biederman
2019-09-12 5:49 ` Yonghong Song
[not found] ` <CACiB22j9M2gmccnh7XqqFp8g7qKFuiOrSAVJiA2tQHLB0pmoSQ@mail.gmail.com>
2019-09-13 2:56 ` Yonghong Song
2019-09-13 11:58 ` Carlos Antonio Neira Bustos
2019-09-13 16:59 ` Eric W. Biederman
2019-09-13 17:28 ` Yonghong Song
2019-09-11 4:32 ` Carlos Antonio Neira Bustos
2019-09-11 8:17 ` Eric W. Biederman
2019-09-10 22:46 ` Yonghong Song
2019-09-11 4:33 ` Carlos Antonio Neira Bustos
2019-09-06 15:09 ` [PATCH bpf-next v10 3/4] tools: Added bpf_get_current_pidns_info helper Carlos Neira
2019-09-06 15:09 ` [PATCH bpf-next v10 4/4] tools/testing/selftests/bpf: Add self-tests for helper bpf_get_pidns_info Carlos Neira
2019-09-10 22:55 ` Yonghong Song
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