Re: [PATCH 0/5 RFC] Add an interface to discover relationships between namespaces

From	ebiederm@xmission.com (Eric W. Biederman)
Newsgroups	linux.kernel
Subject	Re: [PATCH 0/5 RFC] Add an interface to discover relationships between namespaces
Date	2016-07-24 07:30 +0200
Message-ID	<rYk9c-3Qv-17@gated-at.bofh.it> (permalink)
References	<rUTyx-4Je-5@gated-at.bofh.it> <rUWZs-6XY-11@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Andrey Vagin <avagin@openvz.org> writes:

> Hello,
>
> I forgot to add --cc-cover for git send-email, so everyone who is in
> Cc got only a cover letter. All messages were sent in mail lists.
>
> Sorry for inconvenience.

Mostly the code looked sensible.  But I had a couple of issues.
Resend this in September (when the merge window is closed and I am back
from vacation) and I will give this a thorough review and get this
merged.  Or possibly next week if Linus releases another -rc

> On Thu, Jul 14, 2016 at 11:20 AM, Andrey Vagin <avagin@openvz.org> wrote:
>> Each namespace has an owning user namespace and now there is not way
>> to discover these relationships.
>>
>> Pid and user namepaces are hierarchical. There is no way to discover
>> parent-child relationships too.
>>
>> Why we may want to know relationships between namespaces?
>>
>> One use would be visualization, in order to understand the running system.
>> Another would be to answer the question: what capability does process X have to
>> perform operations on a resource governed by namespace Y?
>>
>> One more use-case (which usually called abnormal) is checkpoint/restart.
>> In CRIU we age going to dump and restore nested namespaces.
>>
>> There [1] was a discussion about which interface to choose to determing
>> relationships between namespaces.
>>
>> Eric suggested to add two ioctl-s [2]:
>>> Grumble, Grumble.  I think this may actually a case for creating ioctls
>>> for these two cases.  Now that random nsfs file descriptors are bind
>>> mountable the original reason for using proc files is not as pressing.
>>>
>>> One ioctl for the user namespace that owns a file descriptor.
>>> One ioctl for the parent namespace of a namespace file descriptor.
>>
>> Here is an implementaions of these ioctl-s.
>>
>> [1] https://lkml.org/lkml/2016/7/6/158
>> [2] https://lkml.org/lkml/2016/7/9/101
>>
>> Cc: "Eric W. Biederman" <ebiederm@xmission.com>
>> Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
>> Cc: "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com>
>> Cc: "W. Trevor King" <wking@tremily.us>
>> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
>> Cc: Serge Hallyn <serge.hallyn@canonical.com>


Eric

Thread

[PATCH 0/5 RFC] Add an interface to discover relationships between namespaces Andrey Vagin <avagin@openvz.org> - 2016-07-14 20:30 +0200
  [PATCH 2/5] kernel: add a helper to get an owning user namespace for a namespace Andrey Vagin <avagin@openvz.org> - 2016-07-14 20:30 +0200
    Re: [PATCH 2/5] kernel: add a helper to get an owning user namespace  for a namespace "W. Trevor King" <wking@tremily.us> - 2016-07-14 21:10 +0200
  Re: [PATCH 0/5 RFC] Add an interface to discover relationships  between namespaces Andrey Vagin <avagin@openvz.org> - 2016-07-15 00:10 +0200
    [PATCH 5/5] tools/testing: add a test to check nsfs ioctl-s Andrey Vagin <avagin@openvz.org> - 2016-07-15 04:20 +0200
    [PATCH 4/5] nsfs: add ioctl to get a parent namespace Andrey Vagin <avagin@openvz.org> - 2016-07-15 04:20 +0200
      Re: [PATCH 4/5] nsfs: add ioctl to get a parent namespace ebiederm@xmission.com (Eric W. Biederman) - 2016-07-24 07:30 +0200
    [PATCH 3/5] nsfs: add ioctl to get an owning user namespace for ns file descriptor Andrey Vagin <avagin@openvz.org> - 2016-07-15 04:20 +0200
    [PATCH 2/5] kernel: add a helper to get an owning user namespace for a namespace Andrey Vagin <avagin@openvz.org> - 2016-07-15 04:20 +0200
      Re: [PATCH 2/5] kernel: add a helper to get an owning user namespace for a namespace ebiederm@xmission.com (Eric W. Biederman) - 2016-07-24 07:20 +0200
        Re: [PATCH 2/5] kernel: add a helper to get an owning user namespace for a namespace ebiederm@xmission.com (Eric W. Biederman) - 2016-07-24 16:50 +0200
          Re: [PATCH 2/5] kernel: add a helper to get an owning user namespace  for a namespace "W. Trevor King" <wking@tremily.us> - 2016-07-24 19:10 +0200
      Re: [PATCH 2/5] kernel: add a helper to get an owning user namespace  for a namespace "W. Trevor King" <wking@tremily.us> - 2016-07-24 19:00 +0200
    Re: [PATCH 1/5] namespaces: move user_ns into ns_common ebiederm@xmission.com (Eric W. Biederman) - 2016-07-24 07:20 +0200
    Re: [PATCH 0/5 RFC] Add an interface to discover relationships between namespaces ebiederm@xmission.com (Eric W. Biederman) - 2016-07-24 07:30 +0200
  Re: [PATCH 0/5 RFC] Add an interface to discover relationships  between namespaces "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2016-07-21 16:50 +0200
    Re: [PATCH 0/5 RFC] Add an interface to discover relationships  between namespaces Andrey Vagin <avagin@openvz.org> - 2016-07-22 20:30 +0200
      Re: [PATCH 0/5 RFC] Add an interface to discover relationships  between namespaces "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2016-07-25 13:50 +0200
        Re: [PATCH 0/5 RFC] Add an interface to discover relationships between namespaces ebiederm@xmission.com (Eric W. Biederman) - 2016-07-25 15:40 +0200
          Re: [PATCH 0/5 RFC] Add an interface to discover relationships  between namespaces "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2016-07-25 16:50 +0200
            Re: [PATCH 0/5 RFC] Add an interface to discover relationships  between namespaces "Serge E. Hallyn" <serge@hallyn.com> - 2016-07-25 17:00 +0200
              Re: [PATCH 0/5 RFC] Add an interface to discover relationships between namespaces ebiederm@xmission.com (Eric W. Biederman) - 2016-07-25 17:40 +0200
            Re: [PATCH 0/5 RFC] Add an interface to discover relationships between namespaces ebiederm@xmission.com (Eric W. Biederman) - 2016-07-25 17:20 +0200
  Re: [PATCH 0/5 RFC] Add an interface to discover relationships  between namespaces "W. Trevor King" <wking@tremily.us> - 2016-07-23 23:20 +0200
    Re: [PATCH 0/5 RFC] Add an interface to discover relationships  between namespaces James Bottomley <James.Bottomley@HansenPartnership.com> - 2016-07-23 23:40 +0200
      Re: [PATCH 0/5 RFC] Add an interface to discover relationships  between namespaces "W. Trevor King" <wking@tremily.us> - 2016-07-24 00:10 +0200
        Re: [PATCH 0/5 RFC] Add an interface to discover relationships between namespaces ebiederm@xmission.com (Eric W. Biederman) - 2016-07-24 00:20 +0200
          Re: [PATCH 0/5 RFC] Add an interface to discover relationships  between namespaces "W. Trevor King" <wking@tremily.us> - 2016-07-24 00:40 +0200
            Re: [PATCH 0/5 RFC] Add an interface to discover relationships between namespaces ebiederm@xmission.com (Eric W. Biederman) - 2016-07-24 07:10 +0200

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