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, 2 insertions, 3 deletions

diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index 83f7d42d5c76..2f78f0ce2664 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -532,13 +532,12 @@ static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,
                             void *ptr)
 {
         struct super_block *sb = ptr;
+        struct nfs_net *nn = net_generic(sb->s_fs_info, nfs_net_id);
         struct nfs_client *clp;
         int error = 0;
 
         spin_lock(&nfs_client_lock);
-        list_for_each_entry(clp, &nfs_client_list, cl_share_link) {
-                if (clp->net != sb->s_fs_info)
-                        continue;
+        list_for_each_entry(clp, &nn->nfs_client_list, cl_share_link) {
                 if (clp->rpc_ops != &nfs_v4_clientops)
                         continue;
                 error = __rpc_pipefs_event(clp, event, sb);