bdev/compress: replace RPC parm name with pm_path

We decided to name compress bdevs with COMP_ and then the name of
the underlying bdev so the RPC parm name was stale.  Previously
hardcoded the path to PM for early dev so replaced name with pm_path.

Note that a sample create looks like this now:

rpc.py construct_compress_bdev -b NVMe0n1 -p ~/pm_files -d compress_isal

And that devs need to pay attention for the pathname they provide, its
easy to leave orphaned pm files around and they can get big.

Change-Id: Ifb5245c922461bbecec4bef266bdeb25e8b87f31
Signed-off-by: paul luse <paul.e.luse@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/452235
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>

lib/bdev/compress/vbdev_compress.c

@@ -60,8 +60,6 @@
 
 #define COMP_BDEV_NAME "compress"
 
-/* TODO: need to get this from RPC on create or reduce metadata on load */
-#define TEST_MD_PATH "/tmp"
 #define DEV_CHUNK_SZ (16 * 1024)
 #define DEV_LBA_SZ 512
 #define DEV_BACKING_IO_SZ (4 * 1024)
@@ -991,7 +989,7 @@ _prepare_for_load_init(struct spdk_bdev *bdev)
 
 /* Call reducelib to initialize a new volume */
 static void
-vbdev_init_reduce(struct spdk_bdev *bdev, const char *vbdev_name, const char *comp_pmd)
+vbdev_init_reduce(struct spdk_bdev *bdev, const char *pm_path, const char *comp_pmd)
 {
 	struct vbdev_compress *meta_ctx;
 	int rc;
@@ -1015,7 +1013,7 @@ vbdev_init_reduce(struct spdk_bdev *bdev, const char *vbdev_name, const char *co
 	 * in load.
 	 */
 	spdk_reduce_vol_init(&meta_ctx->params, &meta_ctx->backing_dev,
-			     TEST_MD_PATH,
+			     pm_path,
 			     vbdev_reduce_init_cb,
 			     meta_ctx);
 }
@@ -1110,7 +1108,7 @@ comp_bdev_ch_destroy_cb(void *io_device, void *ctx_buf)
 
 /* RPC entry point for compression vbdev creation. */
 int
-create_compress_bdev(const char *bdev_name, const char *vbdev_name, const char *comp_pmd)
+create_compress_bdev(const char *bdev_name, const char *pm_path, const char *comp_pmd)
 {
 	struct spdk_bdev *bdev;
 
@@ -1119,7 +1117,7 @@ create_compress_bdev(const char *bdev_name, const char *vbdev_name, const char *
 		return -ENODEV;
 	}
 
-	vbdev_init_reduce(bdev, vbdev_name, comp_pmd);
+	vbdev_init_reduce(bdev, pm_path, comp_pmd);
 	return 0;
 }
 

lib/bdev/compress/vbdev_compress.h

@@ -44,11 +44,11 @@ typedef void (*spdk_delete_compress_complete)(void *cb_arg, int bdeverrno);
  * Create new compression bdev.
  *
  * \param bdev_name Bdev on which compression bdev will be created.
- * \param vbdev_name Compression bdev name.
+ * \param pm_path Path to persistent memory.
  * \param comp_pmd Compression PMD name.
  * \return 0 on success, other on failure.
  */
-int create_compress_bdev(const char *bdev_name, const char *vbdev_name, const char *comp_pmd);
+int create_compress_bdev(const char *bdev_name, const char *pm_path, const char *comp_pmd);
 
 /**
  * Delete compress bdev.

lib/bdev/compress/vbdev_compress_rpc.c

@@ -40,7 +40,7 @@
 /* Structure to hold the parameters for this RPC method. */
 struct rpc_construct_compress {
 	char *base_bdev_name;
-	char *name;
+	char *pm_path;
 	char *comp_pmd;
 };
 
@@ -49,14 +49,14 @@ static void
 free_rpc_construct_compress(struct rpc_construct_compress *r)
 {
 	free(r->base_bdev_name);
-	free(r->name);
+	free(r->pm_path);
 	free(r->comp_pmd);
 }
 
 /* Structure to decode the input parameters for this RPC method. */
 static const struct spdk_json_object_decoder rpc_construct_compress_decoders[] = {
 	{"base_bdev_name", offsetof(struct rpc_construct_compress, base_bdev_name), spdk_json_decode_string},
-	{"name", offsetof(struct rpc_construct_compress, name), spdk_json_decode_string},
+	{"pm_path", offsetof(struct rpc_construct_compress, pm_path), spdk_json_decode_string},
 	{"comp_pmd", offsetof(struct rpc_construct_compress, comp_pmd), spdk_json_decode_string},
 };
 
@@ -69,6 +69,7 @@ spdk_rpc_construct_compress_bdev(struct spdk_jsonrpc_request *request,
 {
 	struct rpc_construct_compress req = {NULL};
 	struct spdk_json_write_ctx *w;
+	char *name;
 	int rc;
 
 	if (spdk_json_decode_object(params, rpc_construct_compress_decoders,
@@ -78,7 +79,7 @@ spdk_rpc_construct_compress_bdev(struct spdk_jsonrpc_request *request,
 		goto invalid;
 	}
 
-	rc = create_compress_bdev(req.base_bdev_name, req.name, req.comp_pmd);
+	rc = create_compress_bdev(req.base_bdev_name, req.pm_path, req.comp_pmd);
 	if (rc != 0) {
 		goto invalid;
 	}
@@ -89,9 +90,11 @@ spdk_rpc_construct_compress_bdev(struct spdk_jsonrpc_request *request,
 		return;
 	}
 
-	spdk_json_write_string(w, req.name);
+	name = spdk_sprintf_alloc("COMP_%s", req.base_bdev_name);
+	spdk_json_write_string(w, name);
 	spdk_jsonrpc_end_result(request, w);
 	free_rpc_construct_compress(&req);
+	free(name);
 	return;
 
 invalid:

scripts/rpc.py

@@ -134,12 +134,12 @@ if __name__ == "__main__":
     def construct_compress_bdev(args):
         print(rpc.bdev.construct_compress_bdev(args.client,
                                                base_bdev_name=args.base_bdev_name,
-                                               name=args.name,
+                                               pm_path=args.pm_path,
                                                comp_pmd=args.comp_pmd))
     p = subparsers.add_parser('construct_compress_bdev',
                               help='Add a compress vbdev')
     p.add_argument('-b', '--base_bdev_name', help="Name of the base bdev")
-    p.add_argument('-c', '--name', help="Name of the compress vbdev")
+    p.add_argument('-p', '--pm_path', help="Path to persistent memory")
     p.add_argument('-d', '--comp_pmd', help="Name of the compression device driver")
     p.set_defaults(func=construct_compress_bdev)
 

scripts/rpc/bdev.py

@@ -15,18 +15,18 @@ def set_bdev_options(client, bdev_io_pool_size=None, bdev_io_cache_size=None):
     return client.call('set_bdev_options', params)
 
 
-def construct_compress_bdev(client, base_bdev_name, name, comp_pmd):
+def construct_compress_bdev(client, base_bdev_name, pm_path, comp_pmd):
     """Construct a compress virtual block device.
 
     Args:
         base_bdev_name: name of the underlying base bdev
-        name: name for the compress vbdev
+        pm_path: path to persistent memory
         comp_pmd: name of of the DPDK compression driver to use
 
     Returns:
         Name of created virtual block device.
     """
-    params = {'base_bdev_name': base_bdev_name, 'name': name, 'comp_pmd': comp_pmd}
+    params = {'base_bdev_name': base_bdev_name, 'pm_path': pm_path, 'comp_pmd': comp_pmd}
 
     return client.call('construct_compress_bdev', params)