From: Sagi Grimberg sagi@grimberg.me
stable inclusion from linux-4.19.149 commit 03dfb191acea76e6f92379abdbb5335139b28ffa
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[ Upstream commit 3b4b19721ec652ad2c4fe51dfbe5124212b5f581 ]
Revert fab7772bfbcf ("nvme-multipath: revalidate nvme_ns_head gendisk in nvme_validate_ns")
When adding a new namespace to the head disk (via nvme_mpath_set_live) we will see partition scan which triggers I/O on the mpath device node. This process will usually be triggered from the scan_work which holds the scan_lock. If I/O blocks (if we got ana change currently have only available paths but none are accessible) this can deadlock on the head disk bd_mutex as both partition scan I/O takes it, and head disk revalidation takes it to check for resize (also triggered from scan_work on a different path). See trace [1].
The mpath disk revalidation was originally added to detect online disk size change, but this is no longer needed since commit cb224c3af4df ("nvme: Convert to use set_capacity_revalidate_and_notify") which already updates resize info without unnecessarily revalidating the disk (the mpath disk doesn't even implement .revalidate_disk fop).
[1]:
Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/nvme/host/core.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 9c0836106460..801c5b082782 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -1591,7 +1591,6 @@ static void __nvme_revalidate_disk(struct gendisk *disk, struct nvme_id_ns *id) if (ns->head->disk) { nvme_update_disk_info(ns->head->disk, ns, id); blk_queue_stack_limits(ns->head->disk->queue, ns->queue); - revalidate_disk(ns->head->disk); } #endif }