rbd/rpc: Add a rpc call to get the info of the clusters.

Purpose: Let the users know the current available registered Rados
cluster and the related info.

Change-Id: I115c129ae6e4b0372579aad168fd88f8be136357
Signed-off-by: Ziye Yang <ziye.yang@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/7990
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

CHANGELOG.md

@@ -30,6 +30,9 @@ device.
 Revised `bdev_rbd_create` parameter, it allows to use an optional parameter --cluster-name
 to create a rbd bdev with  an already registered Rados Cluster Object.
 
+New RPC `bdev_rbd_get_clusters_info` was added, it allows to get the info of the registered
+Rados Cluster names.
+
 ## v21.04:
 
 ### accel

doc/jsonrpc.md

@@ -3405,6 +3405,45 @@ Example response:
 }
 ~~
 
+## bdev_rbd_get_clusters_info {#rpc_bdev_rbd_get_clusters_info}
+
+This method is available only if SPDK was build with Ceph RBD support.
+
+### Result
+
+Returns the cluster info of the Rados Cluster name if provided. Otherwise, it
+returns the cluster info of every registered Raods Cluster name.
+
+### Parameters
+
+Name                    | Optional | Type        | Description
+----------------------- | -------- | ----------- | -------------------------
+name                    | Optional | string      | Rados cluster object name
+
+### Example
+
+Example request:
+
+~~
+{
+  "params": {
+    "name": "rbd_cluster"
+  },
+  "jsonrpc": "2.0",
+  "method": "bdev_rbd_get_clusters_info",
+  "id": 1
+}
+~~
+
+Example response:
+
+~~
+{
+  "jsonrpc": "2.0",
+  "cluster_name": "rbd_cluster"
+}
+~~
+
 ## bdev_rbd_create {#rpc_bdev_rbd_create}
 
 Create @ref bdev_config_rbd bdev

module/bdev/rbd/bdev_rbd.c

@@ -790,6 +790,76 @@ bdev_rbd_write_config_json(struct spdk_bdev *bdev, struct spdk_json_write_ctx *w
 	spdk_json_write_object_end(w);
 }
 
+static void
+dump_single_cluster_entry(struct bdev_rbd_cluster *entry, struct spdk_json_write_ctx *w)
+{
+	assert(entry != NULL);
+
+	spdk_json_write_object_begin(w);
+	spdk_json_write_named_string(w, "cluster_name", entry->name);
+
+	if (entry->user_id) {
+		spdk_json_write_named_string(w, "user_id", entry->user_id);
+	}
+
+	if (entry->config_param) {
+		char **config_entry = entry->config_param;
+
+		spdk_json_write_named_object_begin(w, "config_param");
+		while (*config_entry) {
+			spdk_json_write_named_string(w, config_entry[0], config_entry[1]);
+			config_entry += 2;
+		}
+		spdk_json_write_object_end(w);
+	} else if (entry->config_file) {
+		spdk_json_write_named_string(w, "config_file", entry->config_file);
+	}
+
+	spdk_json_write_object_end(w);
+}
+
+int
+bdev_rbd_get_clusters_info(struct spdk_jsonrpc_request *request, const char *name)
+{
+	struct bdev_rbd_cluster *entry;
+	struct spdk_json_write_ctx *w;
+
+	pthread_mutex_lock(&g_map_bdev_rbd_cluster_mutex);
+
+	if (STAILQ_EMPTY(&g_map_bdev_rbd_cluster)) {
+		pthread_mutex_unlock(&g_map_bdev_rbd_cluster_mutex);
+		return -ENOENT;
+	}
+
+	/* If cluster name is provided */
+	if (name) {
+		STAILQ_FOREACH(entry, &g_map_bdev_rbd_cluster, link) {
+			if (strcmp(name, entry->name) == 0) {
+				w = spdk_jsonrpc_begin_result(request);
+				dump_single_cluster_entry(entry, w);
+				spdk_jsonrpc_end_result(request, w);
+
+				pthread_mutex_unlock(&g_map_bdev_rbd_cluster_mutex);
+				return 0;
+			}
+		}
+
+		pthread_mutex_unlock(&g_map_bdev_rbd_cluster_mutex);
+		return -ENOENT;
+	}
+
+	w = spdk_jsonrpc_begin_result(request);
+	spdk_json_write_array_begin(w);
+	STAILQ_FOREACH(entry, &g_map_bdev_rbd_cluster, link) {
+		dump_single_cluster_entry(entry, w);
+	}
+	spdk_json_write_array_end(w);
+	spdk_jsonrpc_end_result(request, w);
+	pthread_mutex_unlock(&g_map_bdev_rbd_cluster_mutex);
+
+	return 0;
+}
+
 static const struct spdk_bdev_fn_table rbd_fn_table = {
 	.destruct		= bdev_rbd_destruct,
 	.submit_request		= bdev_rbd_submit_request,

module/bdev/rbd/bdev_rbd.h

@@ -37,6 +37,7 @@
 #include "spdk/stdinc.h"
 
 #include "spdk/bdev.h"
+#include "spdk/rpc.h"
 
 struct cluster_register_info {
 	char *name;
@@ -86,4 +87,13 @@ int bdev_rbd_register_cluster(struct cluster_register_info *info);
  */
 int bdev_rbd_unregister_cluster(const char *name);
 
+/**
+ * Show the cluster info of a given name. If given name is empty,
+ * the info of every registered cluster name will be showed.
+ *
+ * \param request the json request.
+ * \param name the name of the cluster.
+ */
+int bdev_rbd_get_clusters_info(struct spdk_jsonrpc_request *request, const char *name);
+
 #endif /* SPDK_BDEV_RBD_H */

module/bdev/rbd/bdev_rbd_rpc.c

@@ -32,7 +32,6 @@
  */
 
 #include "bdev_rbd.h"
-#include "spdk/rpc.h"
 #include "spdk/util.h"
 #include "spdk/string.h"
 #include "spdk/log.h"
@@ -336,3 +335,43 @@ cleanup:
 	free_rpc_bdev_cluster_unregister(&req);
 }
 SPDK_RPC_REGISTER("bdev_rbd_unregister_cluster", rpc_bdev_rbd_unregister_cluster, SPDK_RPC_RUNTIME)
+
+struct rpc_bdev_rbd_get_cluster_info {
+	char *name;
+};
+
+static void
+free_rpc_bdev_rbd_get_cluster_info(struct rpc_bdev_rbd_get_cluster_info *req)
+{
+	free(req->name);
+}
+
+static const struct spdk_json_object_decoder rpc_bdev_rbd_get_cluster_info_decoders[] = {
+	{"name", offsetof(struct rpc_bdev_rbd_get_cluster_info, name), spdk_json_decode_string, true},
+};
+
+static void
+rpc_bdev_rbd_get_clusters_info(struct spdk_jsonrpc_request *request,
+			       const struct spdk_json_val *params)
+{
+	struct rpc_bdev_rbd_get_cluster_info req = {NULL};
+	int rc;
+
+	if (params && spdk_json_decode_object(params, rpc_bdev_rbd_get_cluster_info_decoders,
+					      SPDK_COUNTOF(rpc_bdev_rbd_get_cluster_info_decoders),
+					      &req)) {
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR,
+						 "spdk_json_decode_object failed");
+		goto cleanup;
+	}
+
+	rc = bdev_rbd_get_clusters_info(request, req.name);
+	if (rc) {
+		spdk_jsonrpc_send_error_response(request, rc, spdk_strerror(-rc));
+		goto cleanup;
+	}
+
+cleanup:
+	free_rpc_bdev_rbd_get_cluster_info(&req);
+}
+SPDK_RPC_REGISTER("bdev_rbd_get_clusters_info", rpc_bdev_rbd_get_clusters_info, SPDK_RPC_RUNTIME)

scripts/rpc.py

@@ -661,6 +661,14 @@ if __name__ == "__main__":
     p.add_argument('name', help='Name of the Rados Cluster only known to rbd bdev')
     p.set_defaults(func=bdev_rbd_unregister_cluster)
 
+    def bdev_rbd_get_clusters_info(args):
+        print_json(rpc.bdev.bdev_rbd_get_clusters_info(args.client, name=args.name))
+
+    p = subparsers.add_parser('bdev_rbd_get_clusters_info',
+                              help='Display registered Rados Cluster names and related info')
+    p.add_argument('-b', '--name', help="Name of the registered Rados Cluster Name. Example: Cluster1", required=False)
+    p.set_defaults(func=bdev_rbd_get_clusters_info)
+
     def bdev_rbd_create(args):
         config = None
         if args.config:

scripts/rpc/bdev.py

@@ -693,6 +693,21 @@ def bdev_rbd_unregister_cluster(client, name):
     return client.call('bdev_rbd_unregister_cluster', params)
 
 
+def bdev_rbd_get_clusters_info(client, name):
+    """Get the cluster(s) info
+
+    Args:
+        name: name of Rados cluster object to query (optional; if omitted, query all clusters)
+
+    Returns:
+        List of registered Rados cluster information objects.
+    """
+    params = {}
+    if name:
+        params['name'] = name
+    return client.call('bdev_rbd_get_clusters_info', params)
+
+
 @deprecated_alias('construct_rbd_bdev')
 def bdev_rbd_create(client, pool_name, rbd_name, block_size, name=None, user=None, config=None, cluster_name=None):
     """Create a Ceph RBD block device.

test/iscsi_tgt/rbd/rbd.sh

@@ -32,6 +32,7 @@ timing_exit start_iscsi_tgt
 $rpc_py iscsi_create_portal_group $PORTAL_TAG $TARGET_IP:$ISCSI_PORT
 $rpc_py iscsi_create_initiator_group $INITIATOR_TAG $INITIATOR_NAME $NETMASK
 rbd_cluster_name="$($rpc_py bdev_rbd_register_cluster iscsi_rbd_cluster)"
+$rpc_py bdev_rbd_get_clusters_info -b $rbd_cluster_name
 rbd_bdev="$($rpc_py bdev_rbd_create $RBD_POOL $RBD_NAME 4096 -c $rbd_cluster_name)"
 $rpc_py bdev_get_bdevs