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Commit 9969ebc5 authored by Alex Elder's avatar Alex Elder Committed by Sage Weil
Browse files

rbd: implement watch/unwatch with new code 



Implement a new function to set up or tear down a watch event
for an mapped rbd image header using the new request code.

Create a new object request type "nodata" to handle this.  And
define rbd_osd_trivial_callback() which simply marks a request done.

Signed-off-by: default avatarAlex Elder <elder@inktank.com>
Reviewed-by: default avatarJosh Durgin <josh.durgin@inktank.com>
parent 86ea43bf

drivers/block/rbd.c

+86 −3
Original line number Diff line number Diff line
@@ -170,7 +170,9 @@ typedef void (*rbd_img_callback_t)(struct rbd_img_request *); 
struct rbd_obj_request;

typedef void (*rbd_obj_callback_t)(struct rbd_obj_request *);



enum obj_request_type { OBJ_REQUEST_BIO, OBJ_REQUEST_PAGES };

enum obj_request_type {

	OBJ_REQUEST_NODATA, OBJ_REQUEST_BIO, OBJ_REQUEST_PAGES

};



struct rbd_obj_request {

	const char		*object_name;
@@ -1083,6 +1085,7 @@ static inline void rbd_img_obj_request_del(struct rbd_img_request *img_request, 
static bool obj_request_type_valid(enum obj_request_type type)

{

	switch (type) {

	case OBJ_REQUEST_NODATA:

	case OBJ_REQUEST_BIO:

	case OBJ_REQUEST_PAGES:

		return true;
@@ -1306,6 +1309,12 @@ static int rbd_obj_request_wait(struct rbd_obj_request *obj_request) 
	return wait_for_completion_interruptible(&obj_request->completion);

}



static void rbd_osd_trivial_callback(struct rbd_obj_request *obj_request,

				struct ceph_osd_op *op)

{

	atomic_set(&obj_request->done, 1);

}



static void rbd_obj_request_complete(struct rbd_obj_request *obj_request)

{

	if (obj_request->callback)
@@ -1500,6 +1509,9 @@ static void rbd_osd_req_callback(struct ceph_osd_request *osd_req, 
	case CEPH_OSD_OP_WRITE:

		rbd_osd_write_callback(obj_request, op);

		break;

	case CEPH_OSD_OP_WATCH:

		rbd_osd_trivial_callback(obj_request, op);

		break;

	default:

		rbd_warn(NULL, "%s: unsupported op %hu\n",

			obj_request->object_name, (unsigned short) opcode);
@@ -1543,6 +1555,8 @@ static struct ceph_osd_request *rbd_osd_req_create( 


	rbd_assert(obj_request_type_valid(obj_request->type));

	switch (obj_request->type) {

	case OBJ_REQUEST_NODATA:

		break;		/* Nothing to do */

	case OBJ_REQUEST_BIO:

		rbd_assert(obj_request->bio_list != NULL);

		osd_req->r_bio = obj_request->bio_list;
@@ -1635,6 +1649,8 @@ static void rbd_obj_request_destroy(struct kref *kref) 


	rbd_assert(obj_request_type_valid(obj_request->type));

	switch (obj_request->type) {

	case OBJ_REQUEST_NODATA:

		break;		/* Nothing to do */

	case OBJ_REQUEST_BIO:

		if (obj_request->bio_list)

			bio_chain_put(obj_request->bio_list);
@@ -1862,6 +1878,72 @@ static int rbd_img_request_submit(struct rbd_img_request *img_request) 
	return 0;

}



/*

 * Request sync osd watch/unwatch.  The value of "start" determines

 * whether a watch request is being initiated or torn down.

 */

static int rbd_dev_header_watch_sync(struct rbd_device *rbd_dev, int start)

{

	struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;

	struct rbd_obj_request *obj_request;

	struct ceph_osd_req_op *op;

	int ret;



	rbd_assert(start ^ !!rbd_dev->watch_event);

	rbd_assert(start ^ !!rbd_dev->watch_request);



	if (start) {

		ret = ceph_osdc_create_event(osdc, rbd_watch_cb, 0, rbd_dev,

						&rbd_dev->watch_event);

		if (ret < 0)

			return ret;

	}



	ret = -ENOMEM;

	obj_request = rbd_obj_request_create(rbd_dev->header_name, 0, 0,

							OBJ_REQUEST_NODATA);

	if (!obj_request)

		goto out_cancel;



	op = rbd_osd_req_op_create(CEPH_OSD_OP_WATCH,

				rbd_dev->watch_event->cookie,

				rbd_dev->header.obj_version, start);

	if (!op)

		goto out_cancel;

	obj_request->osd_req = rbd_osd_req_create(rbd_dev, true,

							obj_request, op);

	rbd_osd_req_op_destroy(op);

	if (!obj_request->osd_req)

		goto out_cancel;



	if (start) {

		rbd_dev->watch_request = obj_request->osd_req;

		ceph_osdc_set_request_linger(osdc, rbd_dev->watch_request);

	}

	ret = rbd_obj_request_submit(osdc, obj_request);

	if (ret)

		goto out_cancel;

	ret = rbd_obj_request_wait(obj_request);

	if (ret)

		goto out_cancel;



	ret = obj_request->result;

	if (ret)

		goto out_cancel;



	if (start)

		goto done;	/* Done if setting up the watch request */

out_cancel:

	/* Cancel the event if we're tearing down, or on error */

	ceph_osdc_cancel_event(rbd_dev->watch_event);

	rbd_dev->watch_event = NULL;

done:

	if (obj_request)

		rbd_obj_request_put(obj_request);



	return ret;

}



static void rbd_request_fn(struct request_queue *q)

{

	struct rbd_device *rbd_dev = q->queuedata;
@@ -3879,7 +3961,8 @@ static int rbd_dev_probe_finish(struct rbd_device *rbd_dev) 
	if (ret)

		goto err_out_bus;



	ret = rbd_req_sync_watch(rbd_dev, 1);

	(void) rbd_req_sync_watch;	/* avoid a warning */

	ret = rbd_dev_header_watch_sync(rbd_dev, 1);

	if (ret)

		goto err_out_bus;
@@ -4042,7 +4125,7 @@ static void rbd_dev_release(struct device *dev) 
						    rbd_dev->watch_request);

	}

	if (rbd_dev->watch_event)

		rbd_req_sync_watch(rbd_dev, 0);

		rbd_dev_header_watch_sync(rbd_dev, 0);



	/* clean up and free blkdev */

	rbd_free_disk(rbd_dev);