lvol: display details of single lvol store RPC

New optional argument added to get_lvol_stores RPC.
If lvol store name or uuid is provided, details
for this single lvol store is displayed.

It follows similar logic as in get_bdevs or get_nbd_disks.

Change-Id: I11e71d98f3cde869addf5cedeb4f33e5cebf53ea
Signed-off-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Reviewed-on: https://review.gerrithub.io/395126
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Maciej Szwed <maciej.szwed@intel.com>
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

lib/bdev/lvol/vbdev_lvol.c

@@ -44,7 +44,7 @@ SPDK_DECLARE_BDEV_MODULE(lvol);
 static TAILQ_HEAD(, lvol_store_bdev) g_spdk_lvol_pairs = TAILQ_HEAD_INITIALIZER(
 			g_spdk_lvol_pairs);
 
-static struct lvol_store_bdev *
+struct lvol_store_bdev *
 vbdev_get_lvs_bdev_by_lvs(struct spdk_lvol_store *lvs_orig)
 {
 	struct spdk_lvol_store *lvs = NULL;

lib/bdev/lvol/vbdev_lvol.h

@@ -71,4 +71,11 @@ struct spdk_lvol_store *vbdev_get_lvol_store_by_uuid(const char *uuid_str);
  */
 struct spdk_lvol_store *vbdev_get_lvol_store_by_name(const char *name);
 
+/**
+ * \brief Search for handle to lvol_store_bdev
+ * \param lvs handle to lvolstore
+ * \return Handle to lvol_store_bdev or NULL if not found.
+ */
+struct lvol_store_bdev *vbdev_get_lvs_bdev_by_lvs(struct spdk_lvol_store *lvs);
+
 #endif /* SPDK_VBDEV_LVOL_H */

lib/bdev/lvol/vbdev_lvol_rpc.c

@@ -422,32 +422,30 @@ invalid:
 /* Logical volume resize feature is disabled, as it is currently work in progress
 SPDK_RPC_REGISTER("resize_lvol_bdev", spdk_rpc_resize_lvol_bdev) */
 
+struct rpc_get_lvol_stores {
+	char *uuid;
+	char *lvs_name;
+};
+
 static void
-spdk_rpc_get_lvol_stores(struct spdk_jsonrpc_request *request,
-			 const struct spdk_json_val *params)
+free_rpc_get_lvol_stores(struct rpc_get_lvol_stores *req)
+{
+	free(req->uuid);
+	free(req->lvs_name);
+}
+
+static const struct spdk_json_object_decoder rpc_get_lvol_stores_decoders[] = {
+	{"uuid", offsetof(struct rpc_get_lvol_stores, uuid), spdk_json_decode_string, true},
+	{"lvs_name", offsetof(struct rpc_get_lvol_stores, lvs_name), spdk_json_decode_string, true},
+};
+
+static void
+spdk_rpc_dump_lvol_store_info(struct spdk_json_write_ctx *w, struct lvol_store_bdev *lvs_bdev)
 {
-	struct spdk_json_write_ctx *w;
-	struct lvol_store_bdev *lvs_bdev;
 	struct spdk_blob_store *bs;
 	uint64_t cluster_size, block_size;
 	char uuid[UUID_STRING_LEN];
 
-	if (params != NULL) {
-		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,
-						 "get_lvol_stores requires no parameters");
-		return;
-	}
-
-	w = spdk_jsonrpc_begin_result(request);
-	if (w == NULL) {
-		return;
-	}
-
-	spdk_json_write_array_begin(w);
-
-	for (lvs_bdev = vbdev_lvol_store_first(); lvs_bdev != NULL;
-	     lvs_bdev = vbdev_lvol_store_next(lvs_bdev)) {
-
 	bs = lvs_bdev->lvs->blobstore;
 	cluster_size = spdk_bs_get_cluster_size(bs);
 	/* Block size of lvols is always size of blob store page */
@@ -479,9 +477,65 @@ spdk_rpc_get_lvol_stores(struct spdk_jsonrpc_request *request,
 
 	spdk_json_write_object_end(w);
 }
+
+static void
+spdk_rpc_get_lvol_stores(struct spdk_jsonrpc_request *request,
+			 const struct spdk_json_val *params)
+{
+	struct rpc_get_lvol_stores req = {};
+	struct spdk_json_write_ctx *w;
+	struct lvol_store_bdev *lvs_bdev = NULL;
+	struct spdk_lvol_store *lvs = NULL;
+	int rc;
+
+	if (params != NULL) {
+		if (spdk_json_decode_object(params, rpc_get_lvol_stores_decoders,
+					    SPDK_COUNTOF(rpc_get_lvol_stores_decoders),
+					    &req)) {
+			SPDK_INFOLOG(SPDK_LOG_LVOL_RPC, "spdk_json_decode_object failed\n");
+			rc = -EINVAL;
+			goto invalid;
+		}
+
+		rc = vbdev_get_lvol_store_by_uuid_xor_name(req.uuid, req.lvs_name, &lvs);
+		if (rc != 0) {
+			goto invalid;
+		}
+
+		lvs_bdev = vbdev_get_lvs_bdev_by_lvs(lvs);
+		if (lvs_bdev == NULL) {
+			rc = -ENODEV;
+			goto invalid;
+		}
+	}
+
+	w = spdk_jsonrpc_begin_result(request);
+	if (w == NULL) {
+		return;
+	}
+
+	spdk_json_write_array_begin(w);
+
+	if (lvs_bdev != NULL) {
+		spdk_rpc_dump_lvol_store_info(w, lvs_bdev);
+	} else {
+		for (lvs_bdev = vbdev_lvol_store_first(); lvs_bdev != NULL;
+		     lvs_bdev = vbdev_lvol_store_next(lvs_bdev)) {
+			spdk_rpc_dump_lvol_store_info(w, lvs_bdev);
+		}
+	}
 	spdk_json_write_array_end(w);
 
 	spdk_jsonrpc_end_result(request, w);
+
+	free_rpc_get_lvol_stores(&req);
+
+	return;
+
+invalid:
+	spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,
+					 spdk_strerror(-rc));
+	free_rpc_get_lvol_stores(&req);
 }
 
 SPDK_RPC_REGISTER("get_lvol_stores", spdk_rpc_get_lvol_stores)

scripts/rpc.py

@@ -275,6 +275,8 @@ if __name__ == "__main__":
     p.set_defaults(func=rpc.lvol.destroy_lvol_store)
 
     p = subparsers.add_parser('get_lvol_stores', help='Display current logical volume store list')
+    p.add_argument('-u', '--uuid', help='lvol store UUID', required=False)
+    p.add_argument('-l', '--lvs_name', help='lvol store name', required=False)
     p.set_defaults(func=rpc.lvol.get_lvol_stores)
 
     # nbd

scripts/rpc/lvol.py

@@ -46,4 +46,11 @@ def destroy_lvol_store(args):
 
 
 def get_lvol_stores(args):
-    print_dict(args.client.call('get_lvol_stores'))
+    params = {}
+    if (args.uuid and args.lvs_name):
+        print("You can only specify either uuid or name of lvolstore")
+    if args.uuid:
+        params['uuid'] = args.uuid
+    if args.lvs_name:
+        params['lvs_name'] = args.lvs_name
+    print_dict(args.client.call('get_lvol_stores', params))