NFS: Introduce a vector of migration recovery ops

The differences between minor version 0 and minor version 1
migration will be abstracted by the addition of a set of migration
recovery ops.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 259f8be..2aacd13 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -7881,6 +7881,14 @@
 };
 #endif
 
+static const struct nfs4_mig_recovery_ops nfs40_mig_recovery_ops = {
+};
+
+#if defined(CONFIG_NFS_V4_1)
+static const struct nfs4_mig_recovery_ops nfs41_mig_recovery_ops = {
+};
+#endif	/* CONFIG_NFS_V4_1 */
+
 static const struct nfs4_minor_version_ops nfs_v4_0_minor_ops = {
 	.minor_version = 0,
 	.init_caps = NFS_CAP_READDIRPLUS
@@ -7896,6 +7904,7 @@
 	.reboot_recovery_ops = &nfs40_reboot_recovery_ops,
 	.nograce_recovery_ops = &nfs40_nograce_recovery_ops,
 	.state_renewal_ops = &nfs40_state_renewal_ops,
+	.mig_recovery_ops = &nfs40_mig_recovery_ops,
 };
 
 #if defined(CONFIG_NFS_V4_1)
@@ -7916,6 +7925,7 @@
 	.reboot_recovery_ops = &nfs41_reboot_recovery_ops,
 	.nograce_recovery_ops = &nfs41_nograce_recovery_ops,
 	.state_renewal_ops = &nfs41_state_renewal_ops,
+	.mig_recovery_ops = &nfs41_mig_recovery_ops,
 };
 #endif