nfsd: add some comments to the nfsd4 object definitions

Add some comments that describe what each of these objects is, and how
they related to one another.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index 3831ef6..ea6749a 100644
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h
@@ -34,6 +34,14 @@
 struct cld_net;
 struct nfsd4_client_tracking_ops;
 
+/*
+ * Represents a nfsd "container". With respect to nfsv4 state tracking, the
+ * fields of interest are the *_id_hashtbls and the *_name_tree. These track
+ * the nfs4_client objects by either short or long form clientid.
+ *
+ * Each nfsd_net runs a nfs4_laundromat workqueue job when necessary to clean
+ * up expired clients and delegations within the container.
+ */
 struct nfsd_net {
 	struct cld_net *cld_net;