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SubjectRe: [PATCH] 3.8: access permission filesystem
Date (Eric W. Biederman) writes:

> Olaf Dietsche <> writes:
>> I am in the process of catching up with the last two years or so.
>> Right now, I am at the changes involving user namespaces.
>> I have two possible implementations, both working equally well in a
>> shared environment. Since I am not familiar with namespaces in general
>> and user namespaces in particular, I would like you to look over the
>> patches and tell me, what you think.
>> Are the patches good so far? Are there are any things I missed and must
>> consider? Maybe, I am completely off track? Anything else?
>> I included both patches inline below. The patches are also available as
>> separate branches at github
>> I am leaning toward the second patch. Although it is a little bit longer
>> than the first one, it involves no user id conversions.
> Using kuid's and kgid's throughout as your second patch does is best.
> Conversion is only needed on normal filesystems because they have a
> backing store and reside on disk. As accessfs appears not to have
> backing store, storing things with kuid's and kgid's is the preferred
> method.
> Your first patch is buggy as it uses current_user_ns(). Something a
> filesystem in general should not care about.

I have seen similar uses in other filesystems like ext3, jfs or
debugfs. What would be the correct way to use make_kuid() or make_gid()?

> I don't see anything wrong with your second patch.

Thanks a lot for this fast response and your guidance. So, I will dump
the first and continue with the second patch.

> From what little I understand of accessfs, I expect you will want to
> play with and come up to speed on namespaces, as namespaces change
> the universe of objects you will be dealing with, in some subtle
> but interesting ways. At least assuming anyone in who uses accessfs
> is going to be using more than a single container.
> Eric

Regards, Olaf

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