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Subject: Re: [RFC PATCH 0/7] SUNRPC: Create sysfs files for changing IP
From:   Chuck Lever <chuck.lever@oracle.com>
In-Reply-To: <CAFX2JfmYrCSYfCCGgQ0eghU3WSqk=T38wxkJ7Q42ORw-NFeFQg@mail.gmail.com>
Date:   Wed, 13 Jan 2021 14:48:36 -0500
Cc:     Bruce Fields <bfields@fieldses.org>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>
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References: <20210111214143.553479-1-Anna.Schumaker@Netapp.com>
 <CE510EA5-1E3F-4516-A948-10A0FF31C94F@oracle.com>
 <20210112165911.GH9248@fieldses.org>
 <CAFX2JfmYrCSYfCCGgQ0eghU3WSqk=T38wxkJ7Q42ORw-NFeFQg@mail.gmail.com>
To:     Anna Schumaker <schumaker.anna@gmail.com>
Precedence: bulk


> On Jan 13, 2021, at 2:23 PM, Anna Schumaker <schumaker.anna@gmail.com> =
wrote:
>=20
> On Tue, Jan 12, 2021 at 11:59 AM J. Bruce Fields =
<bfields@fieldses.org> wrote:
>>=20
>> On Tue, Jan 12, 2021 at 08:09:09AM -0500, Chuck Lever wrote:
>>> Hi Anna-
>>>=20
>>>> On Jan 11, 2021, at 4:41 PM, schumaker.anna@gmail.com wrote:
>>>>=20
>>>> From: Anna Schumaker <Anna.Schumaker@Netapp.com>
>>>>=20
>>>> It's possible for an NFS server to go down but come back up with a
>>>> different IP address. These patches provide a way for =
administrators to
>>>> handle this issue by providing a new IP address for xprt sockets to
>>>> connect to.
>>>>=20
>>>> This is a first draft of the code, so any thoughts or suggestions =
would
>>>> be greatly appreciated!
>>>=20
>>> One implementation question, one future question.
>>>=20
>>> Would /sys/kernel/net be a little better? or /sys/kernel/sunrpc ?
>=20
> Possibly! I was trying to match /sys/fs/nfs, but I can definitely
> change this if another location is better.

Ah... since this is a supplement to the mount() interface, maybe
placing this new API under /sys/fs/nfs/ might make some sense.


>>> Do you have a plan to integrate support for fs_locations to probe
>>> servers for alternate IP addresses? Would that be a userspace
>>> utility that would plug values into this new /sys API?
>=20
> Yeah, I would expect there to be a new utility to help with assigning
> new values. I haven't given any thought to using fs_locations yet, but
> it could probably work.

I could see a tool that performs an fs_locations from user space
and plugs that information into the kernel NFS client as needed.
Future work!


--
Chuck Lever