Commit 3a6ff827 authored by Xiaodong Liu's avatar Xiaodong Liu Committed by Daniel Verkamp
Browse files

nbd: fix hidden danger caused by stop rpc 



If occasionally there is unflushed data in kernel,
nbd disconnect ioctl will not return, until these
data are flushed. spdk_nbd_disk should process these
data in flushing.
But at present, spdk_nbd_disk is running on a some
reactor with rpc. It is a hidden danger of deadlock.

Change-Id: I2850105dff78f09f0e1b3c0a570dbbf7efdb469e
Signed-off-by: default avatarXiaodong Liu <xiaodong.liu@intel.com>
Reviewed-on: https://review.gerrithub.io/391707


Tested-by: default avatarSPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: default avatarJim Harris <james.r.harris@intel.com>
Reviewed-by: default avatarDaniel Verkamp <daniel.verkamp@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-by: default avatarChangpeng Liu <changpeng.liu@intel.com>
parent 6d982645

lib/nbd/nbd_rpc.c

+75 −15
Original line number Diff line number Diff line
@@ -31,6 +31,8 @@ 
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */



#include "spdk/string.h"

#include "spdk/env.h"

#include "spdk/rpc.h"

#include "spdk/util.h"
@@ -118,47 +120,105 @@ static const struct spdk_json_object_decoder rpc_stop_nbd_disk_decoders[] = { 
	{"nbd_device", offsetof(struct rpc_stop_nbd_disk, nbd_device), spdk_json_decode_string},

};



struct nbd_disconnect_arg {

	struct spdk_jsonrpc_request *request;

	struct spdk_nbd_disk *nbd;

};



static void *

nbd_disconnect_thread(void *arg)

{

	struct nbd_disconnect_arg *thd_arg = arg;

	struct spdk_json_write_ctx *w;



	spdk_unaffinitize_thread();



	nbd_disconnect(thd_arg->nbd);



	w = spdk_jsonrpc_begin_result(thd_arg->request);

	if (w == NULL) {

		goto out;

	}



	spdk_json_write_bool(w, true);

	spdk_jsonrpc_end_result(thd_arg->request, w);



out:

	free(thd_arg);

	pthread_exit(NULL);

}



static void

spdk_rpc_stop_nbd_disk(struct spdk_jsonrpc_request *request,

		       const struct spdk_json_val *params)

{

	struct rpc_stop_nbd_disk req = {};

	struct spdk_json_write_ctx *w;

	struct spdk_nbd_disk *nbd;

	pthread_t tid;

	struct nbd_disconnect_arg *thd_arg = NULL;

	char buf[64];

	int rc;



	if (spdk_json_decode_object(params, rpc_stop_nbd_disk_decoders,

				    SPDK_COUNTOF(rpc_stop_nbd_disk_decoders),

				    &req)) {

		SPDK_ERRLOG("spdk_json_decode_object failed\n");

		goto invalid;

		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,

						 "Invalid parameters");

		goto out;

	}



	if (req.nbd_device == NULL) {

		goto invalid;

		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,

						 "Invalid parameters");

		goto out;

	}



	/* make sure nbd_device is registered */

	nbd = spdk_nbd_disk_find_by_nbd_path(req.nbd_device);

	if (!nbd) {

		goto invalid;

		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,

						 "Invalid parameters");

		goto out;

	}



	nbd_disconnect(nbd);

	/*

	 * thd_arg should be freed by created thread

	 * if thread is created successfully.

	 */

	thd_arg = malloc(sizeof(*thd_arg));

	if (!thd_arg) {

		spdk_strerror_r(-ENOMEM, buf, sizeof(buf));

		SPDK_ERRLOG("could not allocate nbd disconnect thread arg: %s\n", buf);

		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR, buf);

		goto out;

	}



	free_rpc_stop_nbd_disk(&req);

	thd_arg->request = request;

	thd_arg->nbd = nbd;



	w = spdk_jsonrpc_begin_result(request);

	if (w == NULL) {

		return;

	/*

	 * NBD ioctl of disconnect will block until data are flushed.

	 * Create separate thread to execute it.

	 */

	rc = pthread_create(&tid, NULL, nbd_disconnect_thread, (void *)thd_arg);

	if (rc != 0) {

		spdk_strerror_r(rc, buf, sizeof(buf));

		SPDK_ERRLOG("could not create nbd disconnect thread: %s\n", buf);

		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR, buf);

		free(thd_arg);

		goto out;

	}



	spdk_json_write_bool(w, true);

	spdk_jsonrpc_end_result(request, w);

	return;

	rc = pthread_detach(tid);

	if (rc != 0) {

		spdk_strerror_r(rc, buf, sizeof(buf));

		SPDK_ERRLOG("could not detach nbd disconnect thread: %s\n", buf);

		goto out;

	}



invalid:

out:

	free_rpc_stop_nbd_disk(&req);

	spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS, "Invalid parameters");

}



SPDK_RPC_REGISTER("stop_nbd_disk", spdk_rpc_stop_nbd_disk)