nfs41: Allow NFSv4 and NFSv4.1 callback services to coexist

Tracks the nfs_callback_info for both versions, enabling the callback
service for v4 and v4.1 to run concurrently and be stopped independently
of each other.

Signed-off-by: Ricardo Labiaga <ricardo.labiaga@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index df2b40d..ac6575c 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -181,7 +181,7 @@
 {
 #ifdef CONFIG_NFS_V4
 	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
-		nfs_callback_down();
+		nfs_callback_down(clp->cl_minorversion);
 #endif /* CONFIG_NFS_V4 */
 }