From: Stanislav Kinsbursky <skinsbursky-bzQdu9zFT3WakBO8gow8eQ@public•gmane.org>
To: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public•gmane.org>
Cc: "Trond.Myklebust-HgOvQuBEEgTQT0dZR+AlfA@public•gmane.org"
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Subject: Re: [PATCH 01/11] SYSCTL: export root and set handling routines
Date: Mon, 19 Dec 2011 16:22:50 +0400 [thread overview]
Message-ID: <4EEF2C9A.8000403@parallels.com> (raw)
In-Reply-To: <m18vm8g951.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
19.12.2011 14:15, Eric W. Biederman пишет:
> Stanislav Kinsbursky<skinsbursky-bzQdu9zFT3WakBO8gow8eQ@public•gmane.org> writes:
>
>> 18.12.2011 02:25, Eric W. Biederman пишет:
>>> Stanislav Kinsbursky<skinsbursky-bzQdu9zFT3WakBO8gow8eQ@public•gmane.org> writes:
>>>
>>>> These routines are required for making SUNRPC sysctl's per network namespace
>>>> context.
>>>
>>> Why does sunrpc require it's own sysctl root? You should be able to use
>>> the generic per network namespace root and call it good.
>>>
>>> What makes register_net_sysctl_table and register_net_sysctl_ro_table
>>> unsuitable for sunrpc. I skimmed through your patches and I haven't
>>> seen anything obvious.
>>>
>>> Eric
>>>
>>
>> Hello, Eric. Sorry for the lack of information.
>> I was considering two ways how to make these sysctl per net ns:
>>
>> 1) Use register_net_sysctl_table and register_net_sysctl_ro_table as you
>> mentioned. This was easy and cheap, but also means, than all user-space
>> programs, tuning SUNRPC will be broken (since all sysctl currently located
>> in"/proc/sys/sunprc/").
>
> Nope. That is a misunderstanding. register_net_sysctl_table works for
> anything under /proc/sys.
>
>> 2) Export sysctl root creation routines and make per-net SUNRPC sysctl
>> root. This approach allows to make any part of sysctl tree per namespace context
>> and thus leave user-space stuff unchanged.
>>
>> BTW, NFS and LockD also have it's sysctls ("/proc/sys/fs/nfs/").
>> And also because of them I've decided, that it would be better to export SYSCTL
>> root creation routines instead of breaking compatibility for all NFS layers by
>> moving all sysctl under /proc/sys/net/ directory.
>>
>> Do you feel that it was a bad decision?
>
> I think it was a misinformed decision.
>
> I fully support not breaking userspace by moving where the sysctls files
> are. If something sounds like I am suggesting moving sysctl files there
> is a miscommunication somewhere.
>
> The concept of a sysctl root as I had envisioned it and essentially as it
> is implemented was a per namespace sysctl tree. Those sysctl trees are
> then unioned together when presented to user space. There should only
> be one root per namespace.
>
> In practice what this means is that register_net_sysctl_table should
> work for any sysctl file anywhere under /proc/sys. I think
> register_net_sysctl_table is the right solution for your problem. The
> only possible caveat I can think of is you might hit Al's performance
> optimizations and need to create a common empty directory first with
> register_sysctl_paths.
>
>
Sorry, but I forgot to mention one more important goal I would like to achieve:
I want to manage sysctl's variables in context of mount owner, but not viewer one.
IOW imagine, that we have one two network namespaces: "A" and "B". Both of them
have it's own net sysctl's root. And we have per-net sysctl "/proc/sys/var".
And for ns "A" variable was set to 0, and for "B" - to 1.
And B's "/proc/sys/var" is accessible from "A" namespace
("/chroot_path/proc/sys/var" for example).
With this configuration I want to read "1" from both namespaces:
owner "B" (/proc/sys/var) and "A" ("/chroot_path/proc/sys/var").
Looks like simple using of register_net_sysctl_table doesn't allow me this,
because current net ns is used. And to achieve this goal I need my own sysctl
set for SUNRPC like it was done for network namespaces.
> ....
> That said since I am in the process of rewriting things some of this
> may change a little bit, but hopefully not in ways that immediately
> effect the users of register_sysctl_table.
>
> Don't use register_net_sysctl_ro_table. I think what the implementors
> actually wanted was register_net_sysctl_table(&init_net, ...) and didn't
> know it.
>
> Don't put subdirectories in your sysctl tables. Use a ctl_path to
> specify the entire directory where the files should show up. Generally
> the code is easier to read in that form, and the code is simpler to deal
> with if we don't have to worry about directories.
>
> Don't play with the sysctl roots. It is my intention to completely kill
> them off and replace them by moving the per net sysctl tree under
> /proc/<pid>/sys/. Leaving behind symlinks in /proc/sys/net and I guess
> ultimately in /proc/sys/sunrpc/ and /proc/sys/fs/nfs... Which actually
> seems to better describe your mental model.
>
I'm afraid, that this approach this not allow me to achieve the goal, mentioned
above, because current->nsproxy->net_ns will be used during lookup.
Or maybe I misunderstanding here?
> Thank you for mentioning /proc/sys/fs/nfs. That is a case I hadn't
> thought about. In thinking about it I see some deficiencies in my
> rewrite that I need to correct before I push that code.
>
Was glad to be usefull.
> Eric
--
Best regards,
Stanislav Kinsbursky
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next prev parent reply other threads:[~2011-12-19 12:22 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-14 11:44 [PATCH 00/11] SUNRPC: make sysctl per network namespcase context Stanislav Kinsbursky
2011-12-14 11:44 ` [PATCH 01/11] SYSCTL: export root and set handling routines Stanislav Kinsbursky
[not found] ` <20111214104449.3991.61989.stgit-bi+AKbBUZKagILUCTcTcHdKyNwTtLsGr@public.gmane.org>
2011-12-17 22:25 ` Eric W. Biederman
[not found] ` <m1bor6rg39.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2011-12-19 8:56 ` Stanislav Kinsbursky
2011-12-19 10:15 ` Eric W. Biederman
[not found] ` <m18vm8g951.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2011-12-19 12:22 ` Stanislav Kinsbursky [this message]
[not found] ` <4EEF2C9A.8000403-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2011-12-19 16:37 ` Eric W. Biederman
[not found] ` <m1pqfkecw0.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2011-12-19 17:24 ` Stanislav Kinsbursky
[not found] ` <4EEF7364.8000407-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-01-03 3:49 ` Eric W. Biederman
[not found] ` <m1vcotigyb.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2012-01-10 10:38 ` Stanislav Kinsbursky
[not found] ` <4F0C150F.1020007-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-01-10 22:39 ` Eric W. Biederman
2012-01-11 9:47 ` Stanislav Kinsbursky
2012-01-11 17:21 ` Eric W. Biederman
[not found] ` <m1sjjm40k8.fsf-+imSwln9KH6u2/kzUuoCbdi2O/JbrIOy@public.gmane.org>
2012-01-11 18:02 ` Stanislav Kinsbursky
2012-01-11 19:36 ` Eric W. Biederman
2012-01-12 9:17 ` Stanislav Kinsbursky
2011-12-14 11:44 ` [PATCH 02/11] SUNRPC: use syctl path instead of dummy parent table Stanislav Kinsbursky
[not found] ` <20111214103602.3991.20990.stgit-bi+AKbBUZKagILUCTcTcHdKyNwTtLsGr@public.gmane.org>
2011-12-14 11:45 ` [PATCH 03/11] SUNRPC: sysctl root for debug table introduced Stanislav Kinsbursky
2011-12-14 11:45 ` [PATCH 09/11] SUNRPC: remove xs_tcp_fin_timeout variable Stanislav Kinsbursky
2011-12-14 11:45 ` [PATCH 04/11] SUNRPC: per-net sysctl's set introduced Stanislav Kinsbursky
2011-12-14 11:45 ` [PATCH 05/11] SUNRPC: register debug sysctl table per network namespace Stanislav Kinsbursky
2011-12-14 11:45 ` [PATCH 06/11] SUNRPC: register xs_tunables " Stanislav Kinsbursky
2011-12-14 11:45 ` [PATCH 07/11] SUNRPC: xs tunables per network namespace introduced Stanislav Kinsbursky
2011-12-14 11:45 ` [PATCH 08/11] SUNRPC: use per-net xs tunables instead of static ones Stanislav Kinsbursky
2011-12-14 11:46 ` [PATCH 10/11] SUNRPC: allow debug flags modifications only from init_net Stanislav Kinsbursky
2011-12-14 11:46 ` [PATCH 11/11] SUNRPC: sysctl table for rpc_debug introduced Stanislav Kinsbursky
2012-02-07 11:44 ` [PATCH 00/11] SUNRPC: make sysctl per network namespcase context Stanislav Kinsbursky
[not found] ` <4F310E8E.5040608-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-02-07 13:21 ` Myklebust, Trond
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