Re: [PATCH v2] Lockd: pass network namespace to creation and destruction routines

["J. Bruce Fields" <bfields@fieldses.org>]

On Thu, Mar 29, 2012 at 06:54:33PM +0400, Stanislav Kinsbursky wrote:
> v2: dereference of most probably already released nlm_host removed in
> nlmclnt_done() and reclaimer().

Did you want this in Trond's tree or mine?

--b.

> 
> These routines are called from locks reclaimer() kernel thread. This thread
> works in "init_net" network context and currently relays on persence on lockd
> thread and it's per-net resources. Thus lockd_up() and lockd_down() can't relay
> on current network context. So let's pass corrent one into them.
> 
> Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
> 
> Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
> 
> ---
>  fs/lockd/clntlock.c        |   13 ++++++++-----
>  fs/lockd/svc.c             |    7 +++----
>  fs/nfsd/nfssvc.c           |    6 +++---
>  include/linux/lockd/bind.h |    4 ++--
>  4 files changed, 16 insertions(+), 14 deletions(-)
> 
> diff --git a/fs/lockd/clntlock.c b/fs/lockd/clntlock.c
> index ba1dc2e..ca0a080 100644
> --- a/fs/lockd/clntlock.c
> +++ b/fs/lockd/clntlock.c
> @@ -56,7 +56,7 @@ struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init)
>  	u32 nlm_version = (nlm_init->nfs_version == 2) ? 1 : 4;
>  	int status;
>  
> -	status = lockd_up();
> +	status = lockd_up(nlm_init->net);
>  	if (status < 0)
>  		return ERR_PTR(status);
>  
> @@ -65,7 +65,7 @@ struct nlm_host *nlmclnt_init(const struct nlmclnt_initdata *nlm_init)
>  				   nlm_init->hostname, nlm_init->noresvport,
>  				   nlm_init->net);
>  	if (host == NULL) {
> -		lockd_down();
> +		lockd_down(nlm_init->net);
>  		return ERR_PTR(-ENOLCK);
>  	}
>  
> @@ -80,8 +80,10 @@ EXPORT_SYMBOL_GPL(nlmclnt_init);
>   */
>  void nlmclnt_done(struct nlm_host *host)
>  {
> +	struct net *net = host->net;
> +
>  	nlmclnt_release_host(host);
> -	lockd_down();
> +	lockd_down(net);
>  }
>  EXPORT_SYMBOL_GPL(nlmclnt_done);
>  
> @@ -220,11 +222,12 @@ reclaimer(void *ptr)
>  	struct nlm_wait	  *block;
>  	struct file_lock *fl, *next;
>  	u32 nsmstate;
> +	struct net *net = host->net;
>  
>  	allow_signal(SIGKILL);
>  
>  	down_write(&host->h_rwsem);
> -	lockd_up();	/* note: this cannot fail as lockd is already running */
> +	lockd_up(net);	/* note: this cannot fail as lockd is already running */
>  
>  	dprintk("lockd: reclaiming locks for host %s\n", host->h_name);
>  
> @@ -275,6 +278,6 @@ restart:
>  
>  	/* Release host handle after use */
>  	nlmclnt_release_host(host);
> -	lockd_down();
> +	lockd_down(net);
>  	return 0;
>  }
> diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
> index b34100e..ce4c80e 100644
> --- a/fs/lockd/svc.c
> +++ b/fs/lockd/svc.c
> @@ -295,11 +295,10 @@ static void lockd_down_net(struct net *net)
>  /*
>   * Bring up the lockd process if it's not already up.
>   */
> -int lockd_up(void)
> +int lockd_up(struct net *net)
>  {
>  	struct svc_serv *serv;
>  	int		error = 0;
> -	struct net *net = current->nsproxy->net_ns;
>  
>  	mutex_lock(&nlmsvc_mutex);
>  	/*
> @@ -377,12 +376,12 @@ EXPORT_SYMBOL_GPL(lockd_up);
>   * Decrement the user count and bring down lockd if we're the last.
>   */
>  void
> -lockd_down(void)
> +lockd_down(struct net *net)
>  {
>  	mutex_lock(&nlmsvc_mutex);
>  	if (nlmsvc_users) {
>  		if (--nlmsvc_users) {
> -			lockd_down_net(current->nsproxy->net_ns);
> +			lockd_down_net(net);
>  			goto out;
>  		}
>  	} else {
> diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
> index fce472f..0f3e35b 100644
> --- a/fs/nfsd/nfssvc.c
> +++ b/fs/nfsd/nfssvc.c
> @@ -220,7 +220,7 @@ static int nfsd_startup(unsigned short port, int nrservs)
>  	ret = nfsd_init_socks(port);
>  	if (ret)
>  		goto out_racache;
> -	ret = lockd_up();
> +	ret = lockd_up(&init_net);
>  	if (ret)
>  		goto out_racache;
>  	ret = nfs4_state_start();
> @@ -229,7 +229,7 @@ static int nfsd_startup(unsigned short port, int nrservs)
>  	nfsd_up = true;
>  	return 0;
>  out_lockd:
> -	lockd_down();
> +	lockd_down(&init_net);
>  out_racache:
>  	nfsd_racache_shutdown();
>  	return ret;
> @@ -246,7 +246,7 @@ static void nfsd_shutdown(void)
>  	if (!nfsd_up)
>  		return;
>  	nfs4_state_shutdown();
> -	lockd_down();
> +	lockd_down(&init_net);
>  	nfsd_racache_shutdown();
>  	nfsd_up = false;
>  }
> diff --git a/include/linux/lockd/bind.h b/include/linux/lockd/bind.h
> index 11a966e..4d24d64 100644
> --- a/include/linux/lockd/bind.h
> +++ b/include/linux/lockd/bind.h
> @@ -54,7 +54,7 @@ extern void	nlmclnt_done(struct nlm_host *host);
>  
>  extern int	nlmclnt_proc(struct nlm_host *host, int cmd,
>  					struct file_lock *fl);
> -extern int	lockd_up(void);
> -extern void	lockd_down(void);
> +extern int	lockd_up(struct net *net);
> +extern void	lockd_down(struct net *net);
>  
>  #endif /* LINUX_LOCKD_BIND_H */
>