net: add symlinks to ref_tracker_dir for netns

After assigning the inode number to the namespace, use it to create a
unique name for each netns refcount tracker with the ns.inum and
net_cookie values in it, and register a symlink to the debugfs file for
it.

init_net is registered before the ref_tracker dir is created, so add a
late_initcall() to register its files and symlinks.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20250618-reftrack-dbgfs-v15-8-24fc37ead144@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
index aa1e34181ed6f353921a23411fa227b612db661a..45de05d8f0877a4e717bdad4ed776ae27f98944a 100644 (file)
--- a/net/core/net_namespace.c
+++ b/net/core/net_namespace.c
@@ -791,12 +791,40 @@ struct net *get_net_ns_by_pid(pid_t pid)
 }
 EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
 
+#ifdef CONFIG_NET_NS_REFCNT_TRACKER
+static void net_ns_net_debugfs(struct net *net)
+{
+       ref_tracker_dir_symlink(&net->refcnt_tracker, "netns-%llx-%u-refcnt",
+                               net->net_cookie, net->ns.inum);
+       ref_tracker_dir_symlink(&net->notrefcnt_tracker, "netns-%llx-%u-notrefcnt",
+                               net->net_cookie, net->ns.inum);
+}
+
+static int __init init_net_debugfs(void)
+{
+       ref_tracker_dir_debugfs(&init_net.refcnt_tracker);
+       ref_tracker_dir_debugfs(&init_net.notrefcnt_tracker);
+       net_ns_net_debugfs(&init_net);
+       return 0;
+}
+late_initcall(init_net_debugfs);
+#else
+static void net_ns_net_debugfs(struct net *net)
+{
+}
+#endif
+
 static __net_init int net_ns_net_init(struct net *net)
 {
+       int ret;
+
 #ifdef CONFIG_NET_NS
        net->ns.ops = &netns_operations;
 #endif
-       return ns_alloc_inum(&net->ns);
+       ret = ns_alloc_inum(&net->ns);
+       if (!ret)
+               net_ns_net_debugfs(net);
+       return ret;
 }
 
 static __net_exit void net_ns_net_exit(struct net *net)