[Devel] Re: [PATCH 4/5] NFS: remove RPC PipeFS mount point reference from blocklayout routines

[Peng Tao]

On Wed, Nov 30, 2011 at 1:19 AM, Trond Myklebust
<Trond.Myklebust at netapp.com> wrote:
> On Tue, 2011-11-29 at 11:42 -0500, J. Bruce Fields wrote:
>> On Tue, Nov 29, 2011 at 11:40:30AM -0500, Trond Myklebust wrote:
>> > I mean that I'm perfectly entitled to do
>> >
>> > 'modprobe -r blocklayoutdriver'
>> >
>> > and when I do that, then I expect blkmapd to close the rpc pipe and wait
>> > for a new one to be created just like rpc.idmapd and rpc.gssd do when I
>> > remove the nfs and sunrpc modules.
>>
>> The rpc pipefs mount doesn't hold a reference on the sunrpc module?
>
> I stand corrected: the mount does hold a reference to the sunrpc
> module.
> However nothing holds a reference to the blocklayoutdriver module, so
> the main point that the "blocklayout" pipe can disappear from underneath
> the blkmapd stands.
Thanks for the explanation and I agree it can cause problem if user
reload blocklayout module. I will look into a fix to blkmapd.

Best,
Tao