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Commit e124a82f authored by Alex Elder's avatar Alex Elder
Browse files

rbd: protect the rbd_dev_list with a spinlock 



The rbd_dev_list is just a simple list of all the current
rbd_devices.  Using the ctl_mutex as a concurrency guard is
overkill.  Instead, use a spinlock for that specific purpose.

This also reduces the window that the ctl_mutex needs to be held in
rbd_add().

Signed-off-by: default avatarAlex Elder <elder@dreamhost.com>
Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent 1ddbe94e

drivers/block/rbd.c

+22 −11
Original line number Original line Diff line number Diff line
@@ -174,11 +174,13 @@ static struct bus_type rbd_bus_type = { 
	.name		= "rbd",

	.name		= "rbd",

};

};





static DEFINE_SPINLOCK(node_lock);      /* protects client get/put */



static DEFINE_MUTEX(ctl_mutex);	  /* Serialize open/close/setup/teardown */

static DEFINE_MUTEX(ctl_mutex);	  /* Serialize open/close/setup/teardown */



static LIST_HEAD(rbd_dev_list);    /* devices */

static LIST_HEAD(rbd_dev_list);    /* devices */

static DEFINE_SPINLOCK(rbd_dev_list_lock);



static LIST_HEAD(rbd_client_list);      /* clients */

static LIST_HEAD(rbd_client_list);      /* clients */

static DEFINE_SPINLOCK(node_lock);      /* protects client get/put */





static int __rbd_init_snaps_header(struct rbd_device *rbd_dev);

static int __rbd_init_snaps_header(struct rbd_device *rbd_dev);

static void rbd_dev_release(struct device *dev);

static void rbd_dev_release(struct device *dev);
@@ -2209,12 +2211,12 @@ static ssize_t rbd_add(struct bus_type *bus, 
	init_rwsem(&rbd_dev->header.snap_rwsem);

	init_rwsem(&rbd_dev->header.snap_rwsem);





	/* generate unique id: one more than highest used so far */

	/* generate unique id: one more than highest used so far */

	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);



	rbd_dev->id = rbd_id_get();

	rbd_dev->id = rbd_id_get();





	/* add to global list */

	/* add to global list */

	spin_lock(&rbd_dev_list_lock);

	list_add_tail(&rbd_dev->node, &rbd_dev_list);

	list_add_tail(&rbd_dev->node, &rbd_dev_list);

	spin_unlock(&rbd_dev_list_lock);





	/* parse add command */

	/* parse add command */

	if (sscanf(buf, "%" __stringify(RBD_MAX_OPT_LEN) "s "

	if (sscanf(buf, "%" __stringify(RBD_MAX_OPT_LEN) "s "
@@ -2238,12 +2240,14 @@ static ssize_t rbd_add(struct bus_type *bus, 




	/* initialize rest of new object */

	/* initialize rest of new object */

	snprintf(rbd_dev->name, DEV_NAME_LEN, DRV_NAME "%d", rbd_dev->id);

	snprintf(rbd_dev->name, DEV_NAME_LEN, DRV_NAME "%d", rbd_dev->id);



	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);

	rc = rbd_get_client(rbd_dev, mon_dev_name, options);

	rc = rbd_get_client(rbd_dev, mon_dev_name, options);

	mutex_unlock(&ctl_mutex);



	if (rc < 0)

	if (rc < 0)

		goto err_out_slot;

		goto err_out_slot;





	mutex_unlock(&ctl_mutex);



	/* pick the pool */

	/* pick the pool */

	osdc = &rbd_dev->rbd_client->client->osdc;

	osdc = &rbd_dev->rbd_client->client->osdc;

	rc = ceph_pg_poolid_by_name(osdc->osdmap, rbd_dev->pool_name);

	rc = ceph_pg_poolid_by_name(osdc->osdmap, rbd_dev->pool_name);
@@ -2275,9 +2279,9 @@ static ssize_t rbd_add(struct bus_type *bus, 
	return count;

	return count;





err_out_bus:

err_out_bus:

	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);

	spin_lock(&rbd_dev_list_lock);

	list_del_init(&rbd_dev->node);

	list_del_init(&rbd_dev->node);

	mutex_unlock(&ctl_mutex);

	spin_unlock(&rbd_dev_list_lock);

	rbd_id_put(target_id);

	rbd_id_put(target_id);





	/* this will also clean up rest of rbd_dev stuff */

	/* this will also clean up rest of rbd_dev stuff */
@@ -2291,10 +2295,10 @@ static ssize_t rbd_add(struct bus_type *bus, 
	unregister_blkdev(rbd_dev->major, rbd_dev->name);

	unregister_blkdev(rbd_dev->major, rbd_dev->name);

err_out_client:

err_out_client:

	rbd_put_client(rbd_dev);

	rbd_put_client(rbd_dev);

	mutex_lock_nested(&ctl_mutex, SINGLE_DEPTH_NESTING);

err_out_slot:

err_out_slot:

	spin_lock(&rbd_dev_list_lock);

	list_del_init(&rbd_dev->node);

	list_del_init(&rbd_dev->node);

	mutex_unlock(&ctl_mutex);

	spin_unlock(&rbd_dev_list_lock);

	rbd_id_put(target_id);

	rbd_id_put(target_id);





	kfree(rbd_dev);

	kfree(rbd_dev);
@@ -2313,11 +2317,15 @@ static struct rbd_device *__rbd_get_dev(unsigned long id) 
	struct list_head *tmp;

	struct list_head *tmp;

	struct rbd_device *rbd_dev;

	struct rbd_device *rbd_dev;





	spin_lock(&rbd_dev_list_lock);

	list_for_each(tmp, &rbd_dev_list) {

	list_for_each(tmp, &rbd_dev_list) {

		rbd_dev = list_entry(tmp, struct rbd_device, node);

		rbd_dev = list_entry(tmp, struct rbd_device, node);

		if (rbd_dev->id == id)

		if (rbd_dev->id == id) {

			spin_unlock(&rbd_dev_list_lock);

			return rbd_dev;

			return rbd_dev;

		}

		}

	}

	spin_unlock(&rbd_dev_list_lock);

	return NULL;

	return NULL;

}

}
@@ -2372,7 +2380,10 @@ static ssize_t rbd_remove(struct bus_type *bus, 
		goto done;

		goto done;

	}

	}





	spin_lock(&rbd_dev_list_lock);

	list_del_init(&rbd_dev->node);

	list_del_init(&rbd_dev->node);

	spin_unlock(&rbd_dev_list_lock);



	rbd_id_put(target_id);

	rbd_id_put(target_id);





	__rbd_remove_all_snaps(rbd_dev);

	__rbd_remove_all_snaps(rbd_dev);