NFS implement v4.0 callback_ident

Use the small id to pointer translator service to provide a unique callback
identifier per SETCLIENTID call used to identify the v4.0 callback service
associated with the clientid.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/client.c

@@ -56,6 +56,30 @@ static DEFINE_SPINLOCK(nfs_client_lock);
 static LIST_HEAD(nfs_client_list);
 static LIST_HEAD(nfs_volume_list);
 static DECLARE_WAIT_QUEUE_HEAD(nfs_client_active_wq);
+#ifdef CONFIG_NFS_V4
+static DEFINE_IDR(cb_ident_idr); /* Protected by nfs_client_lock */
+
+/*
+ * Get a unique NFSv4.0 callback identifier which will be used
+ * by the V4.0 callback service to lookup the nfs_client struct
+ */
+static int nfs_get_cb_ident_idr(struct nfs_client *clp, int minorversion)
+{
+	int ret = 0;
+
+	if (clp->rpc_ops->version != 4 || minorversion != 0)
+		return ret;
+retry:
+	if (!idr_pre_get(&cb_ident_idr, GFP_KERNEL))
+		return -ENOMEM;
+	spin_lock(&nfs_client_lock);
+	ret = idr_get_new(&cb_ident_idr, clp, &clp->cl_cb_ident);
+	spin_unlock(&nfs_client_lock);
+	if (ret == -EAGAIN)
+		goto retry;
+	return ret;
+}
+#endif /* CONFIG_NFS_V4 */
 
 /*
  * RPC cruft for NFS
@@ -144,6 +168,10 @@ static struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_
 	clp->cl_proto = cl_init->proto;
 
 #ifdef CONFIG_NFS_V4
+	err = nfs_get_cb_ident_idr(clp, cl_init->minorversion);
+	if (err)
+		goto error_cleanup;
+
 	INIT_LIST_HEAD(&clp->cl_delegations);
 	spin_lock_init(&clp->cl_lock);
 	INIT_DELAYED_WORK(&clp->cl_renewd, nfs4_renew_state);
@@ -202,10 +230,32 @@ static void nfs4_shutdown_client(struct nfs_client *clp)
 
 	rpc_destroy_wait_queue(&clp->cl_rpcwaitq);
 }
+
+/* idr_remove_all is not needed as all id's are removed by nfs_put_client */
+void nfs_cleanup_cb_ident_idr(void)
+{
+	idr_destroy(&cb_ident_idr);
+}
+
+/* nfs_client_lock held */
+static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
+{
+	if (clp->cl_cb_ident)
+		idr_remove(&cb_ident_idr, clp->cl_cb_ident);
+}
+
 #else
 static void nfs4_shutdown_client(struct nfs_client *clp)
 {
 }
+
+void nfs_cleanup_cb_ident_idr(void)
+{
+}
+
+static void nfs_cb_idr_remove_locked(struct nfs_client *clp)
+{
+}
 #endif /* CONFIG_NFS_V4 */
 
 /*
@@ -244,6 +294,7 @@ void nfs_put_client(struct nfs_client *clp)
 
 	if (atomic_dec_and_lock(&clp->cl_count, &nfs_client_lock)) {
 		list_del(&clp->cl_share_link);
+		nfs_cb_idr_remove_locked(clp);
 		spin_unlock(&nfs_client_lock);
 
 		BUG_ON(!list_empty(&clp->cl_superblocks));

fs/nfs/inode.c

@@ -1612,6 +1612,7 @@ static void __exit exit_nfs_fs(void)
 #ifdef CONFIG_PROC_FS
 	rpc_proc_unregister("nfs");
 #endif
+	nfs_cleanup_cb_ident_idr();
 	unregister_nfs_fs();
 	nfs_fs_proc_exit();
 	nfsiod_stop();

fs/nfs/internal.h

@@ -128,6 +128,7 @@ extern void nfs_umount(const struct nfs_mount_request *info);
 /* client.c */
 extern struct rpc_program nfs_program;
 
+extern void nfs_cleanup_cb_ident_idr(void);
 extern void nfs_put_client(struct nfs_client *);
 extern struct nfs_client *nfs_find_client(const struct sockaddr *, u32);
 extern struct nfs_client *nfs_find_client_next(struct nfs_client *);

fs/nfs/nfs4proc.c

@@ -3484,6 +3484,7 @@ int nfs4_proc_setclientid(struct nfs_client *clp, u32 program,
 	struct nfs4_setclientid setclientid = {
 		.sc_verifier = &sc_verifier,
 		.sc_prog = program,
+		.sc_cb_ident = clp->cl_cb_ident,
 	};
 	struct rpc_message msg = {
 		.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_SETCLIENTID],

include/linux/nfs_fs_sb.h

@@ -71,6 +71,7 @@ struct nfs_client {
 	 */
 	char			cl_ipaddr[48];
 	unsigned char		cl_id_uniquifier;
+	u32			cl_cb_ident;	/* v4.0 callback identifier */
 	const struct nfs4_minor_version_ops *cl_mvops;
 #endif /* CONFIG_NFS_V4 */