Commit f38cb9d9 authored by Ilya Dryomov's avatar Ilya Dryomov
Browse files

rbd: make get_lock_owner_info() return a single locker or NULL 



Make the "num_lockers can be only 0 or 1" assumption explicit and
simplify the API by getting rid of output parameters in preparation
for calling get_lock_owner_info() twice before blocklisting.

Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
Reviewed-by: default avatarDongsheng Yang <dongsheng.yang@easystack.cn>
parent 50164507

drivers/block/rbd.c

+51 −33
Original line number Diff line number Diff line
@@ -3849,10 +3849,17 @@ static void wake_lock_waiters(struct rbd_device *rbd_dev, int result) 
	list_splice_tail_init(&rbd_dev->acquiring_list, &rbd_dev->running_list);

}



static int get_lock_owner_info(struct rbd_device *rbd_dev,

			       struct ceph_locker **lockers, u32 *num_lockers)

static void free_locker(struct ceph_locker *locker)

{

	if (locker)

		ceph_free_lockers(locker, 1);

}



static struct ceph_locker *get_lock_owner_info(struct rbd_device *rbd_dev)

{

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

	struct ceph_locker *lockers;

	u32 num_lockers;

	u8 lock_type;

	char *lock_tag;

	int ret;
@@ -3861,39 +3868,45 @@ static int get_lock_owner_info(struct rbd_device *rbd_dev, 


	ret = ceph_cls_lock_info(osdc, &rbd_dev->header_oid,

				 &rbd_dev->header_oloc, RBD_LOCK_NAME,

				 &lock_type, &lock_tag, lockers, num_lockers);

	if (ret)

		return ret;

				 &lock_type, &lock_tag, &lockers, &num_lockers);

	if (ret) {

		rbd_warn(rbd_dev, "failed to retrieve lockers: %d", ret);

		return ERR_PTR(ret);

	}



	if (*num_lockers == 0) {

	if (num_lockers == 0) {

		dout("%s rbd_dev %p no lockers detected\n", __func__, rbd_dev);

		lockers = NULL;

		goto out;

	}



	if (strcmp(lock_tag, RBD_LOCK_TAG)) {

		rbd_warn(rbd_dev, "locked by external mechanism, tag %s",

			 lock_tag);

		ret = -EBUSY;

		goto out;

		goto err_busy;

	}



	if (lock_type == CEPH_CLS_LOCK_SHARED) {

		rbd_warn(rbd_dev, "shared lock type detected");

		ret = -EBUSY;

		goto out;

		goto err_busy;

	}



	if (strncmp((*lockers)[0].id.cookie, RBD_LOCK_COOKIE_PREFIX,

	WARN_ON(num_lockers != 1);

	if (strncmp(lockers[0].id.cookie, RBD_LOCK_COOKIE_PREFIX,

		    strlen(RBD_LOCK_COOKIE_PREFIX))) {

		rbd_warn(rbd_dev, "locked by external mechanism, cookie %s",

			 (*lockers)[0].id.cookie);

		ret = -EBUSY;

		goto out;

			 lockers[0].id.cookie);

		goto err_busy;

	}



out:

	kfree(lock_tag);

	return ret;

	return lockers;



err_busy:

	kfree(lock_tag);

	ceph_free_lockers(lockers, num_lockers);

	return ERR_PTR(-EBUSY);

}



static int find_watcher(struct rbd_device *rbd_dev,
@@ -3947,51 +3960,56 @@ static int find_watcher(struct rbd_device *rbd_dev, 
static int rbd_try_lock(struct rbd_device *rbd_dev)

{

	struct ceph_client *client = rbd_dev->rbd_client->client;

	struct ceph_locker *lockers;

	u32 num_lockers;

	struct ceph_locker *locker;

	int ret;



	for (;;) {

		locker = NULL;



		ret = rbd_lock(rbd_dev);

		if (ret != -EBUSY)

			return ret;

			goto out;



		/* determine if the current lock holder is still alive */

		ret = get_lock_owner_info(rbd_dev, &lockers, &num_lockers);

		if (ret)

			return ret;



		if (num_lockers == 0)

		locker = get_lock_owner_info(rbd_dev);

		if (IS_ERR(locker)) {

			ret = PTR_ERR(locker);

			locker = NULL;

			goto out;

		}

		if (!locker)

			goto again;



		ret = find_watcher(rbd_dev, lockers);

		ret = find_watcher(rbd_dev, locker);

		if (ret)

			goto out; /* request lock or error */



		rbd_warn(rbd_dev, "breaking header lock owned by %s%llu",

			 ENTITY_NAME(lockers[0].id.name));

			 ENTITY_NAME(locker->id.name));



		ret = ceph_monc_blocklist_add(&client->monc,

					      &lockers[0].info.addr);

					      &locker->info.addr);

		if (ret) {

			rbd_warn(rbd_dev, "blocklist of %s%llu failed: %d",

				 ENTITY_NAME(lockers[0].id.name), ret);

			rbd_warn(rbd_dev, "failed to blocklist %s%llu: %d",

				 ENTITY_NAME(locker->id.name), ret);

			goto out;

		}



		ret = ceph_cls_break_lock(&client->osdc, &rbd_dev->header_oid,

					  &rbd_dev->header_oloc, RBD_LOCK_NAME,

					  lockers[0].id.cookie,

					  &lockers[0].id.name);

		if (ret && ret != -ENOENT)

					  locker->id.cookie, &locker->id.name);

		if (ret && ret != -ENOENT) {

			rbd_warn(rbd_dev, "failed to break header lock: %d",

				 ret);

			goto out;

		}



again:

		ceph_free_lockers(lockers, num_lockers);

		free_locker(locker);

	}



out:

	ceph_free_lockers(lockers, num_lockers);

	free_locker(locker);

	return ret;

}