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Date:   Tue, 12 Jan 2021 11:59:11 -0500
To:     Chuck Lever <chuck.lever@oracle.com>
Cc:     Anna Schumaker <schumaker.anna@gmail.com>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        Anna Schumaker <Anna.Schumaker@Netapp.com>
Subject: Re: [RFC PATCH 0/7] SUNRPC: Create sysfs files for changing IP
Message-ID: <20210112165911.GH9248@fieldses.org>
References: <20210111214143.553479-1-Anna.Schumaker@Netapp.com>
 <CE510EA5-1E3F-4516-A948-10A0FF31C94F@oracle.com>
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From:   bfields@fieldses.org (J. Bruce Fields)
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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 ?
> 
> 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?

We already have dns resolution for fs_locations, right?  Why can't we
use that here?  Is it that the mount call doesn't give us a host name?
Or we don't trust dns to have the updated IP address for some reason?

--b.

> 
> 
> > Anna
> > 
> > 
> > Anna Schumaker (7):
> >  net: Add a /sys/net directory to sysfs
> >  sunrpc: Create a sunrpc directory under /sys/net/
> >  sunrpc: Create a net/ subdirectory in the sunrpc sysfs
> >  sunrpc: Create per-rpc_clnt sysfs kobjects
> >  sunrpc: Create a per-rpc_clnt file for managing the IP address
> >  sunrpc: Prepare xs_connect() for taking NULL tasks
> >  sunrpc: Connect to a new IP address provided by the user
> > 
> > include/linux/sunrpc/clnt.h |   1 +
> > include/net/sock.h          |   4 +
> > net/socket.c                |   8 ++
> > net/sunrpc/Makefile         |   2 +-
> > net/sunrpc/clnt.c           |   5 ++
> > net/sunrpc/sunrpc_syms.c    |   8 ++
> > net/sunrpc/sysfs.c          | 160 ++++++++++++++++++++++++++++++++++++
> > net/sunrpc/sysfs.h          |  22 +++++
> > net/sunrpc/xprtsock.c       |   3 +-
> > 9 files changed, 211 insertions(+), 2 deletions(-)
> > create mode 100644 net/sunrpc/sysfs.c
> > create mode 100644 net/sunrpc/sysfs.h
> > 
> > -- 
> > 2.29.2
> > 
> 
> --
> Chuck Lever
> 
>