nlm_shutdown_hosts_net() cleanup
diff mbox

Message ID 1d1a25d8-a34b-5175-bb6a-9549041c11f4@virtuozzo.com
State New
Headers show

Commit Message

Vasily Averin Oct. 30, 2017, 1:47 p.m. UTC
nlm_complain_hosts() walk through nlm_server_hosts hlist that should be
protected by nlm_host_mutex.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
---
 fs/lockd/host.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Comments

J. Bruce Fields Oct. 30, 2017, 2:49 p.m. UTC | #1
On Mon, Oct 30, 2017 at 04:47:58PM +0300, Vasily Averin wrote:
> nlm_complain_hosts() walk through nlm_server_hosts hlist that should be
> protected by nlm_host_mutex.

I haven't looked at the NLM locking in ages.  Do we know who else might
actually be accessing this list concurrently?

--b.

> 
> Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
> ---
>  fs/lockd/host.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/lockd/host.c b/fs/lockd/host.c
> index d716c99..089c1d7 100644
> --- a/fs/lockd/host.c
> +++ b/fs/lockd/host.c
> @@ -617,9 +617,8 @@ nlm_shutdown_hosts_net(struct net *net)
>  
>  	/* Then, perform a garbage collection pass */
>  	nlm_gc_hosts(net);
> -	mutex_unlock(&nlm_host_mutex);
> -
>  	nlm_complain_hosts(net);
> +	mutex_unlock(&nlm_host_mutex);
>  }
>  
>  /*
> -- 
> 2.7.4
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Vasily Averin Oct. 30, 2017, 2:58 p.m. UTC | #2
On 2017-10-30 17:49, J. Bruce Fields wrote:
> On Mon, Oct 30, 2017 at 04:47:58PM +0300, Vasily Averin wrote:
>> nlm_complain_hosts() walk through nlm_server_hosts hlist that should be
>> protected by nlm_host_mutex.
> 
> I haven't looked at the NLM locking in ages.  Do we know who else might
> actually be accessing this list concurrently?

Thank you for the question, I'll investigate it.

>> Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
>> ---
>>  fs/lockd/host.c | 3 +--
>>  1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/fs/lockd/host.c b/fs/lockd/host.c
>> index d716c99..089c1d7 100644
>> --- a/fs/lockd/host.c
>> +++ b/fs/lockd/host.c
>> @@ -617,9 +617,8 @@ nlm_shutdown_hosts_net(struct net *net)
>>  
>>  	/* Then, perform a garbage collection pass */
>>  	nlm_gc_hosts(net);
>> -	mutex_unlock(&nlm_host_mutex);
>> -
>>  	nlm_complain_hosts(net);
>> +	mutex_unlock(&nlm_host_mutex);
>>  }
>>  
>>  /*
>> -- 
>> 2.7.4
> 
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Jeff Layton Oct. 30, 2017, 3:49 p.m. UTC | #3
On Mon, 2017-10-30 at 10:49 -0400, J. Bruce Fields wrote:
> On Mon, Oct 30, 2017 at 04:47:58PM +0300, Vasily Averin wrote:
> > nlm_complain_hosts() walk through nlm_server_hosts hlist that should be
> > protected by nlm_host_mutex.
> 
> I haven't looked at the NLM locking in ages.  Do we know who else might
> actually be accessing this list concurrently?
> 
> --b.
> 

Since this is a per-net-ns shutdown, I suppose you could have concurrent
 rpc.nfsd's shutting down different namespaces. Holding the mutex for
longer looks like a reasonable fix.

That said...I don't think lockd was ever properly namespace-ified. YMMV
here.

> > 
> > Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
> > ---
> >  fs/lockd/host.c | 3 +--
> >  1 file changed, 1 insertion(+), 2 deletions(-)
> > 
> > diff --git a/fs/lockd/host.c b/fs/lockd/host.c
> > index d716c99..089c1d7 100644
> > --- a/fs/lockd/host.c
> > +++ b/fs/lockd/host.c
> > @@ -617,9 +617,8 @@ nlm_shutdown_hosts_net(struct net *net)
> >  
> >  	/* Then, perform a garbage collection pass */
> >  	nlm_gc_hosts(net);
> > -	mutex_unlock(&nlm_host_mutex);
> > -
> >  	nlm_complain_hosts(net);
> > +	mutex_unlock(&nlm_host_mutex);
> >  }
> >  
> >  /*
> > -- 
> > 2.7.4
> 
> --
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You can add:

Reviewed-by: Jeff Layton <jlayton@redhat.com>
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Patch
diff mbox

diff --git a/fs/lockd/host.c b/fs/lockd/host.c
index d716c99..089c1d7 100644
--- a/fs/lockd/host.c
+++ b/fs/lockd/host.c
@@ -617,9 +617,8 @@  nlm_shutdown_hosts_net(struct net *net)
 
 	/* Then, perform a garbage collection pass */
 	nlm_gc_hosts(net);
-	mutex_unlock(&nlm_host_mutex);
-
 	nlm_complain_hosts(net);
+	mutex_unlock(&nlm_host_mutex);
 }
 
 /*