bdev: introduce 'get_bdevs_config' RPC call

Write information needed to recreate each bdev.

Change-Id: I3d2b24fd4aaa8b98ec558d864cc28b55a899452f
Signed-off-by: Pawel Wodkowski <pawelx.wodkowski@intel.com>
Reviewed-on: https://review.gerrithub.io/401217
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

include/spdk/bdev.h

@@ -43,6 +43,7 @@
 
 #include "spdk/scsi_spec.h"
 #include "spdk/nvme_spec.h"
+#include "spdk/json.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -147,6 +148,15 @@ void spdk_bdev_finish(spdk_bdev_fini_cb cb_fn, void *cb_arg);
  */
 void spdk_bdev_config_text(FILE *fp);
 
+/**
+ * Get the full configuration options for the registered block device modules and created bdevs.
+ *
+ * \param w The pointer to a JSON write context where the configuration will be written.
+ * \return result of \c spdk_bdev_dump_bdev_config_json() or negative error code:
+ * -EINVAL if w == NULL
+ */
+int spdk_bdev_config_json(struct spdk_json_write_ctx *w);
+
 /**
  * Get block device by the block device name.
  *
@@ -230,7 +240,7 @@ struct spdk_bdev *spdk_bdev_desc_get_bdev(struct spdk_bdev_desc *desc);
 bool spdk_bdev_io_type_supported(struct spdk_bdev *bdev, enum spdk_bdev_io_type io_type);
 
 /**
- * Output driver-specific configuration to a JSON stream.
+ * Output driver-specific information to a JSON stream.
  *
  * The JSON write context will be initialized with an open object, so the bdev
  * driver should write a name(based on the driver name) followed by a JSON value
@@ -242,6 +252,24 @@ bool spdk_bdev_io_type_supported(struct spdk_bdev *bdev, enum spdk_bdev_io_type
  */
 int spdk_bdev_dump_info_json(struct spdk_bdev *bdev, struct spdk_json_write_ctx *w);
 
+/**
+ * Output bdev-specific configuration to a JSON stream.
+ *
+ * If supported, the object with following keys will be written:
+ * method - name of the constructor method
+ * params - parameters necessary to recreate this \c bdev
+ *
+ * If \c bdev does not support writing JSON configuration then object will be written
+ * with only one key - the name of this bdev.
+ *
+ * \param w JSON write context. It will store the driver-specific configuration context.
+ * \param bdev block device to query configuration.
+ * \return 0 on success, negated errno on failure.
+ *  -EINVAL - bdev == NULL or w == NULL
+ *  -ENOSYS - this block device doesn't support dumping configuration.
+ */
+int spdk_bdev_write_config_json(struct spdk_bdev *bdev, struct spdk_json_write_ctx *w);
+
 /**
  * Get block device name.
  *

include/spdk_internal/bdev.h

@@ -100,6 +100,14 @@ struct spdk_bdev_module {
 	 */
 	void (*config_text)(FILE *fp);
 
+	/**
+	 * Function called to return a text string representing the
+	 * module's configuration options for inclusion in a configuration file.
+	 *
+	 * \return 0 on success or Bdev specific negative error code.
+	 */
+	int (*config_json)(struct spdk_json_write_ctx *w);
+
 	/** Name for the modules being defined. */
 	const char *name;
 
@@ -172,6 +180,15 @@ struct spdk_bdev_fn_table {
 	 */
 	int (*dump_info_json)(void *ctx, struct spdk_json_write_ctx *w);
 
+	/**
+	 * Output bdev-specific configuration to a JSON stream. Optional - may be NULL.
+	 *
+	 * The JSON write context will be initialized with an open object, so the bdev
+	 * driver should write all data necessary to recreate this bdev by invoking
+	 * constructor method. No other data should be written.
+	 */
+	void (*write_config_json)(struct spdk_bdev *bdev, struct spdk_json_write_ctx *w);
+
 	/** Get spin-time per I/O channel in microseconds.
 	 *  Optional - may be NULL.
 	 */

lib/bdev/bdev.c

@@ -426,6 +426,32 @@ spdk_bdev_config_text(FILE *fp)
 	}
 }
 
+int
+spdk_bdev_config_json(struct spdk_json_write_ctx *w)
+{
+	struct spdk_bdev_module *bdev_module;
+	struct spdk_bdev *bdev;
+
+	if (!w) {
+		return -EINVAL;
+	}
+
+	spdk_json_write_array_begin(w);
+
+	TAILQ_FOREACH(bdev_module, &g_bdev_mgr.bdev_modules, tailq) {
+		if (bdev_module->config_json) {
+			bdev_module->config_json(w);
+		}
+	}
+
+	TAILQ_FOREACH(bdev, &g_bdev_mgr.bdevs, link) {
+		spdk_bdev_write_config_json(bdev, w);
+	}
+
+	spdk_json_write_array_end(w);
+	return 0;
+}
+
 static int
 spdk_bdev_mgmt_channel_create(void *io_device, void *ctx_buf)
 {
@@ -952,6 +978,24 @@ spdk_bdev_dump_info_json(struct spdk_bdev *bdev, struct spdk_json_write_ctx *w)
 	return 0;
 }
 
+int
+spdk_bdev_write_config_json(struct spdk_bdev *bdev, struct spdk_json_write_ctx *w)
+{
+	if (bdev == NULL || w == NULL) {
+		return -EINVAL;
+	}
+
+	if (bdev->fn_table->write_config_json) {
+		bdev->fn_table->write_config_json(bdev, w);
+	} else {
+		spdk_json_write_object_begin(w);
+		spdk_json_write_named_string(w, "name", bdev->name);
+		spdk_json_write_object_end(w);
+	}
+
+	return 0;
+}
+
 static void
 spdk_bdev_qos_get_max_ios_per_timeslice(struct spdk_bdev *bdev)
 {

lib/bdev/rpc/bdev_rpc.c

@@ -177,6 +177,67 @@ invalid:
 }
 SPDK_RPC_REGISTER("get_bdevs", spdk_rpc_get_bdevs)
 
+struct rpc_get_bdevs_config {
+	char *name;
+};
+
+static void
+free_rpc_get_bdevs_config(struct rpc_get_bdevs_config *r)
+{
+	free(r->name);
+}
+
+static const struct spdk_json_object_decoder rpc_dump_bdevs_config_decoders[] = {
+	{"name", offsetof(struct rpc_get_bdevs_config, name), spdk_json_decode_string},
+};
+
+static void
+spdk_rpc_get_bdevs_config(struct spdk_jsonrpc_request *request,
+			  const struct spdk_json_val *params)
+{
+	struct rpc_get_bdevs_config req = {};
+	struct spdk_json_write_ctx *w;
+	struct spdk_bdev *bdev = NULL;
+
+	if (params && spdk_json_decode_object(params, rpc_dump_bdevs_config_decoders,
+					      SPDK_COUNTOF(rpc_dump_bdevs_config_decoders),
+					      &req)) {
+		SPDK_ERRLOG("spdk_json_decode_object failed\n");
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS, "Invalid parameters");
+		return;
+	}
+
+	if (req.name) {
+		bdev = spdk_bdev_get_by_name(req.name);
+		if (bdev == NULL) {
+			SPDK_ERRLOG("bdev '%s' does not exist\n", req.name);
+			spdk_jsonrpc_send_error_response_fmt(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,
+							     "Bdev '%s' not exist", req.name);
+			free_rpc_get_bdevs_config(&req);
+			return;
+		}
+	}
+
+	free_rpc_get_bdevs_config(&req);
+	w = spdk_jsonrpc_begin_result(request);
+	if (w == NULL) {
+		return;
+	}
+
+	spdk_json_write_array_begin(w);
+	if (bdev != NULL) {
+		spdk_bdev_write_config_json(bdev, w);
+	} else {
+		for (bdev = spdk_bdev_first(); bdev != NULL; bdev = spdk_bdev_next(bdev)) {
+			spdk_bdev_write_config_json(bdev, w);
+		}
+	}
+
+	spdk_json_write_array_end(w);
+
+	spdk_jsonrpc_end_result(request, w);
+}
+SPDK_RPC_REGISTER("get_bdevs_config", spdk_rpc_get_bdevs_config)
 
 struct rpc_delete_bdev {
 	char *name;

lib/event/subsystems/bdev/bdev.c

@@ -69,6 +69,7 @@ static struct spdk_subsystem g_spdk_subsystem_bdev = {
 	.init = spdk_bdev_subsystem_initialize,
 	.fini = spdk_bdev_subsystem_finish,
 	.config = spdk_bdev_config_text,
+	.write_config_json = spdk_bdev_config_json,
 };
 
 SPDK_SUBSYSTEM_REGISTER(g_spdk_subsystem_bdev);

scripts/rpc.py

@@ -105,6 +105,11 @@ if __name__ == "__main__":
     p.add_argument('-b', '--name', help="Name of the Blockdev. Example: Nvme0n1", required=False)
     p.set_defaults(func=rpc.bdev.get_bdevs)
 
+    p = subparsers.add_parser(
+        'get_bdevs_config', help='Display current (live) blockdev configuration list or required blockdev')
+    p.add_argument('-b', '--name', help="Name of the Blockdev. Example: Nvme0n1", required=False)
+    p.set_defaults(func=rpc.bdev.get_bdevs_config)
+
     p = subparsers.add_parser('delete_bdev', help='Delete a blockdev')
     p.add_argument(
         'bdev_name', help='Blockdev name to be deleted. Example: Malloc0.')

scripts/rpc/bdev.py

@@ -80,6 +80,13 @@ def get_bdevs(args):
     print_dict(args.client.call('get_bdevs', params))
 
 
+def get_bdevs_config(args):
+    params = {}
+    if args.name:
+        params['name'] = args.name
+    print_dict(args.client.call('get_bdevs_config', params))
+
+
 def delete_bdev(args):
     params = {'name': args.bdev_name}
     args.client.call('delete_bdev', params)

test/unit/lib/bdev/bdev.c/bdev_ut.c

@@ -34,6 +34,7 @@
 #include "spdk_cunit.h"
 
 #include "lib/test_env.c"
+#include "unit/lib/json_mock.c"
 
 /* HACK: disable VTune integration so the unit test doesn't need VTune headers and libs to build */
 #undef SPDK_CONFIG_VTUNE

test/unit/lib/bdev/mt/bdev.c/bdev_ut.c

@@ -34,6 +34,7 @@
 #include "spdk_cunit.h"
 
 #include "lib/test_env.c"
+#include "unit/lib/json_mock.c"
 #include "lib/ut_multithread.c"
 
 /* HACK: disable VTune integration so the unit test doesn't need VTune headers and libs to build */

test/unit/lib/bdev/part.c/part_ut.c

@@ -34,6 +34,7 @@
 #include "spdk_cunit.h"
 
 #include "lib/test_env.c"
+#include "unit/lib/json_mock.c"
 
 /* HACK: disable VTune integration so the unit test doesn't need VTune headers and libs to build */
 #undef SPDK_CONFIG_VTUNE

test/unit/lib/bdev/pmem/bdev_pmem_ut.c

@@ -34,6 +34,7 @@
 #include "spdk_cunit.h"
 
 #include "lib/test_env.c"
+#include "unit/lib/json_mock.c"
 
 #include "bdev/pmem/bdev_pmem.c"
 
@@ -96,11 +97,6 @@ _pmem_send_msg(spdk_thread_fn fn, void *ctx, void *thread_ctx)
 	fn(ctx);
 }
 
-DEFINE_STUB(spdk_json_write_object_begin, int, (struct spdk_json_write_ctx *w), 0);
-DEFINE_STUB(spdk_json_write_object_end, int, (struct spdk_json_write_ctx *w), 0);
-DEFINE_STUB(spdk_json_write_string, int, (struct spdk_json_write_ctx *w, const char *val), 0);
-DEFINE_STUB(spdk_json_write_name, int, (struct spdk_json_write_ctx *w, const char *name), 0);
-
 static PMEMblkpool *
 find_pmemblk_pool(const char *path)
 {