From: Hannes Reinecke hare@suse.de
[ Upstream commit 2b81a5f015199f3d585ce710190a9e87714d3c1e ]
When reading the partition table on initial scan hits an I/O error the I/O will hang with the scan_mutex held:
[<0>] do_read_cache_page+0x49b/0x790 [<0>] read_part_sector+0x39/0xe0 [<0>] read_lba+0xf9/0x1d0 [<0>] efi_partition+0xf1/0x7f0 [<0>] bdev_disk_changed+0x1ee/0x550 [<0>] blkdev_get_whole+0x81/0x90 [<0>] blkdev_get_by_dev+0x128/0x2e0 [<0>] device_add_disk+0x377/0x3c0 [<0>] nvme_mpath_set_live+0x130/0x1b0 [nvme_core] [<0>] nvme_mpath_add_disk+0x150/0x160 [nvme_core] [<0>] nvme_alloc_ns+0x417/0x950 [nvme_core] [<0>] nvme_validate_or_alloc_ns+0xe9/0x1e0 [nvme_core] [<0>] nvme_scan_work+0x168/0x310 [nvme_core] [<0>] process_one_work+0x231/0x420
and trying to delete the controller will deadlock as it tries to grab the scan mutex:
[<0>] nvme_mpath_clear_ctrl_paths+0x25/0x80 [nvme_core] [<0>] nvme_remove_namespaces+0x31/0xf0 [nvme_core] [<0>] nvme_do_delete_ctrl+0x4b/0x80 [nvme_core]
As we're now properly ordering the namespace list there is no need to hold the scan_mutex in nvme_mpath_clear_ctrl_paths() anymore. And we always need to kick the requeue list as the path will be marked as unusable and I/O will be requeued _without_ a current path.
Signed-off-by: Hannes Reinecke hare@suse.de Reviewed-by: Keith Busch kbusch@kernel.org Reviewed-by: Sagi Grimberg sagi@grimberg.me Signed-off-by: Christoph Hellwig hch@lst.de Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/nvme/host/multipath.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index abc9bdfd48bde..a189155d2c60c 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -138,13 +138,12 @@ void nvme_mpath_clear_ctrl_paths(struct nvme_ctrl *ctrl) { struct nvme_ns *ns;
- mutex_lock(&ctrl->scan_lock); down_read(&ctrl->namespaces_rwsem); - list_for_each_entry(ns, &ctrl->namespaces, list) - if (nvme_mpath_clear_current_path(ns)) - kblockd_schedule_work(&ns->head->requeue_work); + list_for_each_entry(ns, &ctrl->namespaces, list) { + nvme_mpath_clear_current_path(ns); + kblockd_schedule_work(&ns->head->requeue_work); + } up_read(&ctrl->namespaces_rwsem); - mutex_unlock(&ctrl->scan_lock); }
static bool nvme_path_is_disabled(struct nvme_ns *ns)