Re: [RFC PATCH 0/7] SUNRPC: Create sysfs files for changing IP

Chuck Lever
2021-01-19T16:07:29Z

> On Jan 14, 2021, at 3:29 PM, Olga Kornievskaia <aglo@umich.edu> wrote:
>
> On Wed, Jan 13, 2021 at 9:18 PM Chuck Lever <chuck.lever@oracle.com> wrote:
>>
>>
>>> On Jan 13, 2021, at 2:48 PM, Chuck Lever <chuck.lever@oracle.com> wrote:
>>>
>>>> On Jan 13, 2021, at 2:23 PM, Anna Schumaker <schumaker.anna@gmail.com> wrote:
>>>>
>>>> On Tue, Jan 12, 2021 at 11:59 AM J. Bruce Fields <bfields@fieldses.org> wrote:
>>>>>
>>>>> On Tue, Jan 12, 2021 at 08:09:09AM -0500, Chuck Lever wrote:
>>>>>> Hi Anna-
>>>>>>
>>>>>>> On Jan 11, 2021, at 4:41 PM, schumaker.anna@gmail.com wrote:
>>>>>>>
>>>>>>> From: Anna Schumaker <Anna.Schumaker@Netapp.com>
>>>>>>>
>>>>>>> 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.
>>>>>>>
>>>>>>> This is a first draft of the code, so any thoughts or suggestions would
>>>>>>> be greatly appreciated!
>>>>>>
>>>>>> One implementation question, one future question.
>>>>>>
>>>>>> Would /sys/kernel/net be a little better? or /sys/kernel/sunrpc ?
>>>>
>>>> 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.
>>
>> Or you could implement it with "-o remount,addr=new-address".
>
> A change of address is currently not allowed by the NFS because
> multiple mounts might be sharing a superblock and change of one
> mount's option would not be correct. The way things work from this new
> mechanism is system wide and all mounts are affected.

OK, well, if we're going with an API based on /sys that shows
underlying transport connections, is there a way to expose
whether the connection is established or closed? Maybe also
last traffic or last connect attempt?

Can it support RPC/RDMA connections too?

--
Chuck Lever