bdev/null: allow user to override UUID

Change-Id: I2fe5eb46d5e5b67451b472b82cde69e3606c6235
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/403222
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>

lib/bdev/null/bdev_null.c

@@ -127,7 +127,8 @@ static const struct spdk_bdev_fn_table null_fn_table = {
 };
 
 struct spdk_bdev *
-create_null_bdev(const char *name, uint64_t num_blocks, uint32_t block_size)
+create_null_bdev(const char *name, const struct spdk_uuid *uuid,
+		 uint64_t num_blocks, uint32_t block_size)
 {
 	struct null_bdev *bdev;
 	int rc;
@@ -158,7 +159,11 @@ create_null_bdev(const char *name, uint64_t num_blocks, uint32_t block_size)
 	bdev->bdev.write_cache = 0;
 	bdev->bdev.blocklen = block_size;
 	bdev->bdev.blockcnt = num_blocks;
-	spdk_uuid_generate(&bdev->bdev.uuid);
+	if (uuid) {
+		bdev->bdev.uuid = *uuid;
+	} else {
+		spdk_uuid_generate(&bdev->bdev.uuid);
+	}
 
 	bdev->bdev.ctxt = bdev;
 	bdev->bdev.fn_table = &null_fn_table;
@@ -281,7 +286,7 @@ bdev_null_initialize(void)
 
 		num_blocks = size_in_mb * (1024 * 1024) / block_size;
 
-		bdev = create_null_bdev(name, num_blocks, block_size);
+		bdev = create_null_bdev(name, NULL, num_blocks, block_size);
 		if (bdev == NULL) {
 			SPDK_ERRLOG("Could not create null bdev\n");
 			rc = EINVAL;

lib/bdev/null/bdev_null.h

@@ -37,7 +37,9 @@
 #include "spdk/stdinc.h"
 
 struct spdk_bdev;
+struct spdk_uuid;
 
-struct spdk_bdev *create_null_bdev(const char *name, uint64_t num_blocks, uint32_t block_size);
+struct spdk_bdev *create_null_bdev(const char *name, const struct spdk_uuid *uuid,
+				   uint64_t num_blocks, uint32_t block_size);
 
 #endif /* SPDK_BDEV_NULL_H */

lib/bdev/null/bdev_null_rpc.c

@@ -41,12 +41,14 @@
 
 struct rpc_construct_null {
 	char *name;
+	char *uuid;
 	uint32_t num_blocks;
 	uint32_t block_size;
 };
 
 static const struct spdk_json_object_decoder rpc_construct_null_decoders[] = {
 	{"name", offsetof(struct rpc_construct_null, name), spdk_json_decode_string},
+	{"uuid", offsetof(struct rpc_construct_null, uuid), spdk_json_decode_string, true},
 	{"num_blocks", offsetof(struct rpc_construct_null, num_blocks), spdk_json_decode_uint32},
 	{"block_size", offsetof(struct rpc_construct_null, block_size), spdk_json_decode_uint32},
 };
@@ -57,6 +59,8 @@ spdk_rpc_construct_null_bdev(struct spdk_jsonrpc_request *request,
 {
 	struct rpc_construct_null req = {};
 	struct spdk_json_write_ctx *w;
+	struct spdk_uuid *uuid = NULL;
+	struct spdk_uuid decoded_uuid;
 	struct spdk_bdev *bdev;
 
 	if (spdk_json_decode_object(params, rpc_construct_null_decoders,
@@ -66,7 +70,14 @@ spdk_rpc_construct_null_bdev(struct spdk_jsonrpc_request *request,
 		goto invalid;
 	}
 
-	bdev = create_null_bdev(req.name, req.num_blocks, req.block_size);
+	if (req.uuid) {
+		if (spdk_uuid_parse(&decoded_uuid, req.uuid)) {
+			goto invalid;
+		}
+		uuid = &decoded_uuid;
+	}
+
+	bdev = create_null_bdev(req.name, uuid, req.num_blocks, req.block_size);
 	if (bdev == NULL) {
 		goto invalid;
 	}

scripts/rpc.py

@@ -41,6 +41,7 @@ if __name__ == "__main__":
     p = subparsers.add_parser('construct_null_bdev',
                               help='Add a bdev with null backend')
     p.add_argument('name', help='Block device name')
+    p.add_argument('-u', '--uuid', help='UUID of the bdev')
     p.add_argument(
         'total_size', help='Size of null bdev in MB (int > 0)', type=int)
     p.add_argument('block_size', help='Block size for this bdev', type=int)

scripts/rpc/bdev.py

@@ -16,6 +16,8 @@ def construct_null_bdev(args):
     num_blocks = (args.total_size * 1024 * 1024) / args.block_size
     params = {'name': args.name, 'num_blocks': num_blocks,
               'block_size': args.block_size}
+    if args.uuid:
+        params['uuid'] = args.uuid
     print_array(args.client.call(
         'construct_null_bdev', params))