replication: Introduce new APIs to do replication operation

This commit introduces six replication interfaces(for block, network etc).
Firstly we can use replication_(new/remove) to create/destroy replication
instances, then in migration we can use replication_(start/stop/do_checkpoint
/get_error)_all to handle all replication operations. More detail please
refer to replication.h

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
Signed-off-by: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
Signed-off-by: Wang WeiWei <wangww.fnst@cn.fujitsu.com>
Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Message-id: 1469602913-20979-9-git-send-email-xiecl.fnst@cn.fujitsu.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 174 insertions, 0 deletions

diff --git a/replication.h b/replication.h
new file mode 100644
index 0000000000..ece6ca6133
--- /dev/null
+++ b/replication.h
@@ -0,0 +1,174 @@
+/*
+ * Replication filter
+ *
+ * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
+ * Copyright (c) 2016 Intel Corporation
+ * Copyright (c) 2016 FUJITSU LIMITED
+ *
+ * Author:
+ *   Changlong Xie <xiecl.fnst@cn.fujitsu.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef REPLICATION_H
+#define REPLICATION_H
+
+#include "qemu/queue.h"
+
+typedef struct ReplicationOps ReplicationOps;
+typedef struct ReplicationState ReplicationState;
+
+/**
+ * SECTION:replication.h
+ * @title:Base Replication System
+ * @short_description: interfaces for handling replication
+ *
+ * The Replication Model provides a framework for handling Replication
+ *
+ * <example>
+ *   <title>How to use replication interfaces</title>
+ *   <programlisting>
+ * #include "replication.h"
+ *
+ * typedef struct BDRVReplicationState {
+ *     ReplicationState *rs;
+ * } BDRVReplicationState;
+ *
+ * static void replication_start(ReplicationState *rs, ReplicationMode mode,
+ *                               Error **errp);
+ * static void replication_do_checkpoint(ReplicationState *rs, Error **errp);
+ * static void replication_get_error(ReplicationState *rs, Error **errp);
+ * static void replication_stop(ReplicationState *rs, bool failover,
+ *                              Error **errp);
+ *
+ * static ReplicationOps replication_ops = {
+ *     .start = replication_start,
+ *     .checkpoint = replication_do_checkpoint,
+ *     .get_error = replication_get_error,
+ *     .stop = replication_stop,
+ * }
+ *
+ * static int replication_open(BlockDriverState *bs, QDict *options,
+ *                             int flags, Error **errp)
+ * {
+ *     BDRVReplicationState *s = bs->opaque;
+ *     s->rs = replication_new(bs, &replication_ops);
+ *     return 0;
+ * }
+ *
+ * static void replication_close(BlockDriverState *bs)
+ * {
+ *     BDRVReplicationState *s = bs->opaque;
+ *     replication_remove(s->rs);
+ * }
+ *
+ * BlockDriver bdrv_replication = {
+ *     .format_name                = "replication",
+ *     .protocol_name              = "replication",
+ *     .instance_size              = sizeof(BDRVReplicationState),
+ *
+ *     .bdrv_open                  = replication_open,
+ *     .bdrv_close                 = replication_close,
+ * };
+ *
+ * static void bdrv_replication_init(void)
+ * {
+ *     bdrv_register(&bdrv_replication);
+ * }
+ *
+ * block_init(bdrv_replication_init);
+ *   </programlisting>
+ * </example>
+ *
+ * We create an example about how to use replication interfaces in above.
+ * Then in migration, we can use replication_(start/stop/do_checkpoint/
+ * get_error)_all to handle all replication operations.
+ */
+
+/**
+ * ReplicationState:
+ * @opaque: opaque pointer value passed to this ReplicationState
+ * @ops: replication operation of this ReplicationState
+ * @node: node that we will insert into @replication_states QLIST
+ */
+struct ReplicationState {
+    void *opaque;
+    ReplicationOps *ops;
+    QLIST_ENTRY(ReplicationState) node;
+};
+
+/**
+ * ReplicationOps:
+ * @start: callback to start replication
+ * @stop: callback to stop replication
+ * @checkpoint: callback to do checkpoint
+ * @get_error: callback to check if error occurred during replication
+ */
+struct ReplicationOps {
+    void (*start)(ReplicationState *rs, ReplicationMode mode, Error **errp);
+    void (*stop)(ReplicationState *rs, bool failover, Error **errp);
+    void (*checkpoint)(ReplicationState *rs, Error **errp);
+    void (*get_error)(ReplicationState *rs, Error **errp);
+};
+
+/**
+ * replication_new:
+ * @opaque: opaque pointer value passed to ReplicationState
+ * @ops: replication operation of the new relevant ReplicationState
+ *
+ * Called to create a new ReplicationState instance, and then insert it
+ * into @replication_states QLIST
+ *
+ * Returns: the new ReplicationState instance
+ */
+ReplicationState *replication_new(void *opaque, ReplicationOps *ops);
+
+/**
+ * replication_remove:
+ * @rs: the ReplicationState instance to remove
+ *
+ * Called to remove a ReplicationState instance, and then delete it from
+ * @replication_states QLIST
+ */
+void replication_remove(ReplicationState *rs);
+
+/**
+ * replication_start_all:
+ * @mode: replication mode that could be "primary" or "secondary"
+ * @errp: returns an error if this function fails
+ *
+ * Start replication, called in migration/checkpoint thread
+ *
+ * Note: the caller of the function MUST make sure vm stopped
+ */
+void replication_start_all(ReplicationMode mode, Error **errp);
+
+/**
+ * replication_do_checkpoint_all:
+ * @errp: returns an error if this function fails
+ *
+ * This interface is called after all VM state is transferred to Secondary QEMU
+ */
+void replication_do_checkpoint_all(Error **errp);
+
+/**
+ * replication_get_error_all:
+ * @errp: returns an error if this function fails
+ *
+ * This interface is called to check if error occurred during replication
+ */
+void replication_get_error_all(Error **errp);
+
+/**
+ * replication_stop_all:
+ * @failover: boolean value that indicates if we need do failover or not
+ * @errp: returns an error if this function fails
+ *
+ * It is called on failover. The vm should be stopped before calling it, if you
+ * use this API to shutdown the guest, or other things except failover
+ */
+void replication_stop_all(bool failover, Error **errp);
+
+#endif /* REPLICATION_H */