[PATCH] Teach cifs about network namespaces.

[Rob Landley <rlandley-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>]

From: Rob Landley <rlandley-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>

Teach cifs about network namespaces, so mounting uses adresses and
routing visible from a container rather than from init context.

For a long drawn out test reproduction sequence, see:

  http://landley.livejournal.com/47024.html
  http://landley.livejournal.com/47205.html
  http://landley.livejournal.com/47476.html

Signed-off-by: Rob Landley <rlandley-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
---

 fs/cifs/cifsglob.h |   32 ++++++++++++++++++++++++++++++++
 fs/cifs/connect.c  |   22 +++++++++++++++++-----
 2 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 7136c0c..86f31bb 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -168,6 +168,9 @@ struct TCP_Server_Info {
 		struct sockaddr_in6 sockAddr6;
 	} addr;
 	struct sockaddr_storage srcaddr; /* locally bind to this IP */
+#ifdef CONFIG_NET_NS
+	struct net *net;
+#endif
 	wait_queue_head_t response_q;
 	wait_queue_head_t request_q; /* if more than maxmpx to srvr must block*/
 	struct list_head pending_mid_q;
@@ -227,6 +230,35 @@ struct TCP_Server_Info {
 };
 
 /*
+ * Macros to allow the TCP_Server_Info->net field and related code to drop out
+ * when CONFIG_NET_NS isn't set.
+ */
+
+static inline struct net *
+cifs_net_ns(struct TCP_Server_Info *srv)
+{
+#ifdef CONFIG_NET_NS
+	return srv->net;
+#else
+	return &init_net;
+#endif
+}
+
+static inline void
+cifs_set_net_ns(struct TCP_Server_Info *srv, struct net *net)
+{
+#ifdef CONFIG_NET_NS
+	srv->net = net;
+#endif
+}
+
+#ifdef CONFIG_NET_NS
+#define cifs_use_net_ns() (1)
+#else
+#define cifs_use_net_ns() (0)
+#endif
+
+/*
  * Session structure.  One of these for each uid session with a particular host
  */
 struct cifsSesInfo {
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index cc1a860..b4faef0 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1545,6 +1545,10 @@ cifs_find_tcp_session(struct sockaddr *addr, struct smb_vol *vol)
 
 	spin_lock(&cifs_tcp_ses_lock);
 	list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) {
+		if (cifs_use_net_ns()
+		    && cifs_net_ns(server) == current->nsproxy->net_ns)
+			continue;
+
 		if (!match_address(server, addr,
 				   (struct sockaddr *)&vol->srcaddr))
 			continue;
@@ -1572,6 +1576,9 @@ cifs_put_tcp_session(struct TCP_Server_Info *server)
 		return;
 	}
 
+	if (cifs_use_net_ns())
+		put_net(cifs_net_ns(server));
+
 	list_del_init(&server->tcp_ses_list);
 	spin_unlock(&cifs_tcp_ses_lock);
 
@@ -1677,6 +1684,9 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
 	       sizeof(tcp_ses->srcaddr));
 	++tcp_ses->srv_count;
 
+	if (cifs_use_net_ns())
+		cifs_set_net_ns(tcp_ses, get_net(current->nsproxy->net_ns));
+
 	if (addr.ss_family == AF_INET6) {
 		cFYI(1, "attempting ipv6 connect");
 		/* BB should we allow ipv6 on port 139? */
@@ -1720,6 +1730,9 @@ cifs_get_tcp_session(struct smb_vol *volume_info)
 out_err_crypto_release:
 	cifs_crypto_shash_release(tcp_ses);
 
+	if (cifs_use_net_ns())
+		put_net(cifs_net_ns(tcp_ses));
+
 out_err:
 	if (tcp_ses) {
 		if (!IS_ERR(tcp_ses->hostname))
@@ -2145,8 +2158,8 @@ ipv4_connect(struct TCP_Server_Info *server)
 	struct socket *socket = server->ssocket;
 
 	if (socket == NULL) {
-		rc = sock_create_kern(PF_INET, SOCK_STREAM,
-				      IPPROTO_TCP, &socket);
+		rc = __sock_create(cifs_net_ns(server), PF_INET,
+				   SOCK_STREAM, IPPROTO_TCP, &socket, 1);
 		if (rc < 0) {
 			cERROR(1, "Error %d creating socket", rc);
 			return rc;
@@ -2310,11 +2323,10 @@ ipv6_connect(struct TCP_Server_Info *server)
 	struct socket *socket = server->ssocket;
 
 	if (socket == NULL) {
-		rc = sock_create_kern(PF_INET6, SOCK_STREAM,
-				      IPPROTO_TCP, &socket);
+		rc = __sock_create(cifs_net_ns(server), PF_INET6,
+				   SOCK_STREAM, IPPROTO_TCP, &socket, 1);
 		if (rc < 0) {
 			cERROR(1, "Error %d creating ipv6 socket", rc);
-			socket = NULL;
 			return rc;
 		}