From e3f70eadb7dddfb5a2bb9afff7abfc6ee17a29d0 Mon Sep 17 00:00:00 2001
From: Stanislav Kinsbursky <skinsbursky@parallels.com>
Date: Thu, 29 Mar 2012 18:54:33 +0400
Subject: [PATCH] Lockd: pass network namespace to creation and destruction
 routines

v2: dereference of most probably already released nlm_host removed in
nlmclnt_done() and reclaimer().

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: J. Bruce Fields <bfields@redhat.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 ba1dc2eebd1e..ca0a08001449 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 @@ reclaimer(void *ptr)
 
 	/* 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 f49b9afc4436..1ead0750cdbb 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);
 	/*
@@ -378,12 +377,12 @@ 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 28dfad39f0c5..78e521392df1 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 11a966e5f829..4d24d64578c4 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 */