Commit 5396fdac authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Christoph Hellwig
Browse files

nvme: fix refcounting imbalance when all paths are down 



When the last path to a ns_head drops the current code
removes the ns_head from the subsystem list, but will only
delete the disk itself if the last reference to the ns_head
drops. This is causing an refcounting imbalance eg when
applications have a reference to the disk, as then they'll
never get notified that the disk is in fact dead.
This patch moves the call 'del_gendisk' into nvme_mpath_check_last_path(),
ensuring that the disk can be properly removed and applications get the
appropriate notifications.

Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarKeith Busch <kbusch@kernel.org>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 7764656b

drivers/nvme/host/core.c

+11 −3
Original line number Diff line number Diff line
@@ -3807,6 +3807,8 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid, 


static void nvme_ns_remove(struct nvme_ns *ns)

{

	bool last_path = false;



	if (test_and_set_bit(NVME_NS_REMOVING, &ns->flags))

		return;
@@ -3815,8 +3817,6 @@ static void nvme_ns_remove(struct nvme_ns *ns) 


	mutex_lock(&ns->ctrl->subsys->lock);

	list_del_rcu(&ns->siblings);

	if (list_empty(&ns->head->list))

		list_del_init(&ns->head->entry);

	mutex_unlock(&ns->ctrl->subsys->lock);



	synchronize_rcu(); /* guarantee not available in head->list */
@@ -3836,7 +3836,15 @@ static void nvme_ns_remove(struct nvme_ns *ns) 
	list_del_init(&ns->list);

	up_write(&ns->ctrl->namespaces_rwsem);



	nvme_mpath_check_last_path(ns);

	/* Synchronize with nvme_init_ns_head() */

	mutex_lock(&ns->head->subsys->lock);

	if (list_empty(&ns->head->list)) {

		list_del_init(&ns->head->entry);

		last_path = true;

	}

	mutex_unlock(&ns->head->subsys->lock);

	if (last_path)

		nvme_mpath_shutdown_disk(ns->head);

	nvme_put_ns(ns);

}

drivers/nvme/host/multipath.c

+8 −1
Original line number Diff line number Diff line
@@ -760,14 +760,21 @@ void nvme_mpath_add_disk(struct nvme_ns *ns, struct nvme_id_ns *id) 
#endif

}



void nvme_mpath_remove_disk(struct nvme_ns_head *head)

void nvme_mpath_shutdown_disk(struct nvme_ns_head *head)

{

	if (!head->disk)

		return;

	kblockd_schedule_work(&head->requeue_work);

	if (head->disk->flags & GENHD_FL_UP) {

		nvme_cdev_del(&head->cdev, &head->cdev_device);

		del_gendisk(head->disk);

	}

}



void nvme_mpath_remove_disk(struct nvme_ns_head *head)

{

	if (!head->disk)

		return;

	blk_set_queue_dying(head->disk->queue);

	/* make sure all pending bios are cleaned up */

	kblockd_schedule_work(&head->requeue_work);

drivers/nvme/host/nvme.h

+2 −9
Original line number Diff line number Diff line
@@ -716,14 +716,7 @@ void nvme_mpath_uninit(struct nvme_ctrl *ctrl); 
void nvme_mpath_stop(struct nvme_ctrl *ctrl);

bool nvme_mpath_clear_current_path(struct nvme_ns *ns);

void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl);



static inline void nvme_mpath_check_last_path(struct nvme_ns *ns)

{

	struct nvme_ns_head *head = ns->head;



	if (head->disk && list_empty(&head->list))

		kblockd_schedule_work(&head->requeue_work);

}

void nvme_mpath_shutdown_disk(struct nvme_ns_head *head);



static inline void nvme_trace_bio_complete(struct request *req)

{
@@ -772,7 +765,7 @@ static inline bool nvme_mpath_clear_current_path(struct nvme_ns *ns) 
static inline void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl)

{

}

static inline void nvme_mpath_check_last_path(struct nvme_ns *ns)

static inline void nvme_mpath_shutdown_disk(struct nvme_ns_head *head)

{

}

static inline void nvme_trace_bio_complete(struct request *req)