NFS: make nfs_client_list per net ns

This patch splits global list of NFS clients into per-net-ns array of lists.
This looks more strict and clearer.
BTW, this patch also makes "/proc/fs/nfsfs/servers" entry content depends on
/proc mount owner pid namespace. See below for details.

NOTE: few words about how was /proc/fs/nfsfs/ entries content show per network
namespace done. This is a little bit tricky and not the best is could be. But
it's cheap (proper fix for /proc conteinerization is a hard nut to crack).
The idea is simple: take proper network namespace from pid namespace
child reaper nsproxy of /proc/ mount creator.
This actually means, that if there are 2 containers with different net
namespace sharing pid namespace, then read of /proc/fs/nfsfs/ entries will
always return content, taken from net namespace of pid namespace creator task
(and thus second namespace set wil be unvisible).

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 27 insertions, 11 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index 98af1cb28ee3..058eb9bcfa9d 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -39,6 +39,8 @@
 #include <net/ipv6.h>
 #include <linux/nfs_xdr.h>
 #include <linux/sunrpc/bc_xprt.h>
+#include <linux/nsproxy.h>
+#include <linux/pid_namespace.h>
 
 #include <asm/system.h>
 
@@ -49,11 +51,11 @@
 #include "internal.h"
 #include "fscache.h"
 #include "pnfs.h"
+#include "netns.h"
 
 #define NFSDBG_FACILITY         NFSDBG_CLIENT
 
 DEFINE_SPINLOCK(nfs_client_lock);
-LIST_HEAD(nfs_client_list);
 static LIST_HEAD(nfs_volume_list);
 static DECLARE_WAIT_QUEUE_HEAD(nfs_client_active_wq);
 #ifdef CONFIG_NFS_V4
@@ -464,8 +466,9 @@ static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *dat
 {
         struct nfs_client *clp;
         const struct sockaddr *sap = data->addr;
+        struct nfs_net *nn = net_generic(data->net, nfs_net_id);
 
-        list_for_each_entry(clp, &nfs_client_list, cl_share_link) {
+        list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
                 const struct sockaddr *clap = (struct sockaddr *)&clp->cl_addr;
                 /* Don't match clients that failed to initialise properly */
                 if (clp->cl_cons_state < 0)
@@ -483,9 +486,6 @@ static struct nfs_client *nfs_match_client(const struct nfs_client_initdata *dat
                 /* Match the full socket address */
                 if (!nfs_sockaddr_cmp(sap, clap))
                         continue;
-                /* Match network namespace */
-                if (clp->net != data->net)
-                        continue;
 
                 atomic_inc(&clp->cl_count);
                 return clp;
@@ -506,6 +506,7 @@ nfs_get_client(const struct nfs_client_initdata *cl_init,
 {
         struct nfs_client *clp, *new = NULL;
         int error;
+        struct nfs_net *nn = net_generic(cl_init->net, nfs_net_id);
 
         dprintk("--> nfs_get_client(%s,v%u)\n",
                 cl_init->hostname ?: "", cl_init->rpc_ops->version);
@@ -531,7 +532,7 @@ nfs_get_client(const struct nfs_client_initdata *cl_init,
         /* install a new client and return with it unready */
 install_client:
         clp = new;
-        list_add(&clp->cl_share_link, &nfs_client_list);
+        list_add(&clp->cl_share_link, &nn->nfs_client_list);
         spin_unlock(&nfs_client_lock);
 
         error = cl_init->rpc_ops->init_client(clp, timeparms, ip_addr,
@@ -1227,9 +1228,10 @@ nfs4_find_client_sessionid(const struct sockaddr *addr,
                            struct nfs4_sessionid *sid)
 {
         struct nfs_client *clp;
+        struct nfs_net *nn = net_generic(&init_net, nfs_net_id);
 
         spin_lock(&nfs_client_lock);
-        list_for_each_entry(clp, &nfs_client_list, cl_share_link) {
+        list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
                 if (nfs4_cb_match_client(addr, clp, 1) == false)
                         continue;
 
@@ -1757,6 +1759,13 @@ out_free_server:
         return ERR_PTR(error);
 }
 
+void nfs_clients_init(struct net *net)
+{
+        struct nfs_net *nn = net_generic(net, nfs_net_id);
+
+        INIT_LIST_HEAD(&nn->nfs_client_list);
+}
+
 #ifdef CONFIG_PROC_FS
 static struct proc_dir_entry *proc_fs_nfs;
 
@@ -1810,13 +1819,15 @@ static int nfs_server_list_open(struct inode *inode, struct file *file)
 {
         struct seq_file *m;
         int ret;
+        struct pid_namespace *pid_ns = file->f_dentry->d_sb->s_fs_info;
+        struct net *net = pid_ns->child_reaper->nsproxy->net_ns;
 
         ret = seq_open(file, &nfs_server_list_ops);
         if (ret < 0)
                 return ret;
 
         m = file->private_data;
-        m->private = PDE(inode)->data;
+        m->private = net;
 
         return 0;
 }
@@ -1826,9 +1837,11 @@ static int nfs_server_list_open(struct inode *inode, struct file *file)
  */
 static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
 {
+        struct nfs_net *nn = net_generic(m->private, nfs_net_id);
+
         /* lock the list against modification */
         spin_lock(&nfs_client_lock);
-        return seq_list_start_head(&nfs_client_list, *_pos);
+        return seq_list_start_head(&nn->nfs_client_list, *_pos);
 }
 
 /*
@@ -1836,7 +1849,9 @@ static void *nfs_server_list_start(struct seq_file *m, loff_t *_pos)
  */
 static void *nfs_server_list_next(struct seq_file *p, void *v, loff_t *pos)
 {
-        return seq_list_next(v, &nfs_client_list, pos);
+        struct nfs_net *nn = net_generic(p->private, nfs_net_id);
+
+        return seq_list_next(v, &nn->nfs_client_list, pos);
 }
 
 /*
@@ -1853,9 +1868,10 @@ static void nfs_server_list_stop(struct seq_file *p, void *v)
 static int nfs_server_list_show(struct seq_file *m, void *v)
 {
         struct nfs_client *clp;
+        struct nfs_net *nn = net_generic(m->private, nfs_net_id);
 
         /* display header on line 1 */
-        if (v == &nfs_client_list) {
+        if (v == &nn->nfs_client_list) {
                 seq_puts(m, "NV SERVER   PORT USE HOSTNAME\n");
                 return 0;
         }