From 5396fdac56d87d04e75e5068c0c92d33625f51e7 Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Fri, 16 Jul 2021 13:30:35 +0200 Subject: 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: Hannes Reinecke Reviewed-by: Keith Busch Signed-off-by: Christoph Hellwig --- drivers/nvme/host/core.c | 14 +++++++++++--- drivers/nvme/host/multipath.c | 9 ++++++++- drivers/nvme/host/nvme.h | 11 ++--------- 3 files changed, 21 insertions(+), 13 deletions(-) (limited to 'drivers/nvme') diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 11779be42186..17c05a4595f0 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -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); } diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index 0ea5298469c3..3f32c5e86bfc 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -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); diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 18ef8dd03a90..5cd1fa3b8464 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -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) -- cgit v1.2.3-59-g8ed1b