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>

fs/nfs/nfs4_fs.h

@@ -50,6 +50,7 @@ struct nfs4_minor_version_ops {
  const struct nfs4_state_recovery_ops *reboot_recovery_ops;
  const struct nfs4_state_recovery_ops *nograce_recovery_ops;
  const struct nfs4_state_maintenance_ops *state_renewal_ops;
+ const struct nfs4_mig_recovery_ops *mig_recovery_ops;
 };
 
 #define NFS_SEQID_CONFIRMED 1
@@ -203,6 +204,9 @@ struct nfs4_state_maintenance_ops {
  int (*renew_lease)(struct nfs_client *, struct rpc_cred *);
 };
 
+struct nfs4_mig_recovery_ops {
+};
+
 extern const struct dentry_operations nfs4_dentry_operations;
 
 /* dir.c */

fs/nfs/nfs4proc.c

@@ -7881,6 +7881,14 @@ static const struct nfs4_state_maintenance_ops nfs41_state_renewal_ops = {
 };
 #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 @@ static const struct nfs4_minor_version_ops nfs_v4_0_minor_ops = {
  .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 @@ static const struct nfs4_minor_version_ops nfs_v4_1_minor_ops = {
  .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