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nvme-multipath: defer partition scanning

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[ Upstream commit 1f021341eef41e77a633186e9be5223de2ce5d48 ]

We need to suppress the partition scan from occuring within the
controller's scan_work context. If a path error occurs here, the IO will
wait until a path becomes available or all paths are torn down, but that
action also occurs within scan_work, so it would deadlock. Defer the
partion scan to a different context that does not block scan_work.

Reported-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Keith Busch 2024-10-15 07:30:17 -07:00 committed by Greg Kroah-Hartman
parent f17c880a47
commit 60de2e03f9
2 changed files with 34 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
drivers/nvme/host/multipath.c
View File

@ -463,6 +463,20 @@ static int nvme_add_ns_head_cdev(struct nvme_ns_head *head)
return ret; return ret;
} }
static void nvme_partition_scan_work(struct work_struct *work)
{
struct nvme_ns_head *head =
container_of(work, struct nvme_ns_head, partition_scan_work);
if (WARN_ON_ONCE(!test_and_clear_bit(GD_SUPPRESS_PART_SCAN,
&head->disk->state)))
return;
mutex_lock(&head->disk->open_mutex);
bdev_disk_changed(head->disk, false);
mutex_unlock(&head->disk->open_mutex);
}
static void nvme_requeue_work(struct work_struct *work) static void nvme_requeue_work(struct work_struct *work)
{ {
struct nvme_ns_head *head = struct nvme_ns_head *head =
@ -489,6 +503,7 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
bio_list_init(&head->requeue_list); bio_list_init(&head->requeue_list);
spin_lock_init(&head->requeue_lock); spin_lock_init(&head->requeue_lock);
INIT_WORK(&head->requeue_work, nvme_requeue_work); INIT_WORK(&head->requeue_work, nvme_requeue_work);
INIT_WORK(&head->partition_scan_work, nvme_partition_scan_work);
/* /*
* Add a multipath node if the subsystems supports multiple controllers. * Add a multipath node if the subsystems supports multiple controllers.
@ -504,6 +519,16 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
return -ENOMEM; return -ENOMEM;
head->disk->fops = &nvme_ns_head_ops; head->disk->fops = &nvme_ns_head_ops;
head->disk->private_data = head; head->disk->private_data = head;
/*
* We need to suppress the partition scan from occuring within the
* controller's scan_work context. If a path error occurs here, the IO
* will wait until a path becomes available or all paths are torn down,
* but that action also occurs within scan_work, so it would deadlock.
* Defer the partion scan to a different context that does not block
* scan_work.
*/
set_bit(GD_SUPPRESS_PART_SCAN, &head->disk->state);
sprintf(head->disk->disk_name, "nvme%dn%d", sprintf(head->disk->disk_name, "nvme%dn%d",
ctrl->subsys->instance, head->instance); ctrl->subsys->instance, head->instance);
@ -552,6 +577,7 @@ static void nvme_mpath_set_live(struct nvme_ns *ns)
return; return;
} }
nvme_add_ns_head_cdev(head); nvme_add_ns_head_cdev(head);
kblockd_schedule_work(&head->partition_scan_work);
} }
mutex_lock(&head->lock); mutex_lock(&head->lock);
@ -851,6 +877,12 @@ void nvme_mpath_shutdown_disk(struct nvme_ns_head *head)
kblockd_schedule_work(&head->requeue_work); kblockd_schedule_work(&head->requeue_work);
if (test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) { if (test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
nvme_cdev_del(&head->cdev, &head->cdev_device); nvme_cdev_del(&head->cdev, &head->cdev_device);
/*
* requeue I/O after NVME_NSHEAD_DISK_LIVE has been cleared
* to allow multipath to fail all I/O.
*/
synchronize_srcu(&head->srcu);
kblockd_schedule_work(&head->requeue_work);
del_gendisk(head->disk); del_gendisk(head->disk);
} }
} }
@ -862,6 +894,7 @@ void nvme_mpath_remove_disk(struct nvme_ns_head *head)
/* make sure all pending bios are cleaned up */ /* make sure all pending bios are cleaned up */
kblockd_schedule_work(&head->requeue_work); kblockd_schedule_work(&head->requeue_work);
flush_work(&head->requeue_work); flush_work(&head->requeue_work);
flush_work(&head->partition_scan_work);
put_disk(head->disk); put_disk(head->disk);
} }

1
drivers/nvme/host/nvme.h
View File

@ -460,6 +460,7 @@ struct nvme_ns_head {
struct bio_list requeue_list; struct bio_list requeue_list;
spinlock_t requeue_lock; spinlock_t requeue_lock;
struct work_struct requeue_work; struct work_struct requeue_work;
struct work_struct partition_scan_work;
struct mutex lock; struct mutex lock;
unsigned long flags; unsigned long flags;
#define NVME_NSHEAD_DISK_LIVE 0 #define NVME_NSHEAD_DISK_LIVE 0