This is a note to let you know that I've just added the patch titled
nvme-multipath: avoid hang on inaccessible namespaces
to the 6.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nvme-multipath-avoid-hang-on-inaccessible-namespaces.patch
and it can be found in the queue-6.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9545c8c79758941a82be8afa1b4d1416b477ed24
Author: Hannes Reinecke <hare@xxxxxxxxxx>
Date: Sat Sep 14 14:01:23 2024 +0200
nvme-multipath: avoid hang on inaccessible namespaces
[ Upstream commit 3b97f5a05cfc55e7729ff3769f63eef64e2178bb ]
During repetitive namespace remapping operations on the target the
namespace might have changed between the time the initial scan
was performed, and partition scan was invoked by device_add_disk()
in nvme_mpath_set_live(). We then end up with a stuck scanning process:
[<0>] folio_wait_bit_common+0x12a/0x310
[<0>] filemap_read_folio+0x97/0xd0
[<0>] do_read_cache_folio+0x108/0x390
[<0>] read_part_sector+0x31/0xa0
[<0>] read_lba+0xc5/0x160
[<0>] efi_partition+0xd9/0x8f0
[<0>] bdev_disk_changed+0x23d/0x6d0
[<0>] blkdev_get_whole+0x78/0xc0
[<0>] bdev_open+0x2c6/0x3b0
[<0>] bdev_file_open_by_dev+0xcb/0x120
[<0>] disk_scan_partitions+0x5d/0x100
[<0>] device_add_disk+0x402/0x420
[<0>] nvme_mpath_set_live+0x4f/0x1f0 [nvme_core]
[<0>] nvme_mpath_add_disk+0x107/0x120 [nvme_core]
[<0>] nvme_alloc_ns+0xac6/0xe60 [nvme_core]
[<0>] nvme_scan_ns+0x2dd/0x3e0 [nvme_core]
[<0>] nvme_scan_work+0x1a3/0x490 [nvme_core]
This happens when we have several paths, some of which are inaccessible,
and the active paths are removed first. Then nvme_find_path() will requeue
I/O in the ns_head (as paths are present), but the requeue list is never
triggered as all remaining paths are inactive.
This patch checks for NVME_NSHEAD_DISK_LIVE in nvme_available_path(),
and requeue I/O after NVME_NSHEAD_DISK_LIVE has been cleared once
the last path has been removed to properly terminate pending I/O.
Signed-off-by: Hannes Reinecke <hare@xxxxxxxxxx>
Reviewed-by: Sagi Grimberg <sagi@xxxxxxxxxxx>
Signed-off-by: Keith Busch <kbusch@xxxxxxxxxx>
Stable-dep-of: 5dd18f09ce73 ("nvme/multipath: Fix RCU list traversal to use SRCU primitive")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index a43982aaa40d7..6b2decd998de5 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -421,6 +421,9 @@ static bool nvme_available_path(struct nvme_ns_head *head)
{
struct nvme_ns *ns;
+ if (!test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags))
+ return NULL;
+
list_for_each_entry_rcu(ns, &head->list, siblings) {
if (test_bit(NVME_CTRL_FAILFAST_EXPIRED, &ns->ctrl->flags))
continue;
@@ -995,8 +998,7 @@ void nvme_mpath_shutdown_disk(struct nvme_ns_head *head)
{
if (!head->disk)
return;
- kblockd_schedule_work(&head->requeue_work);
- if (test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
+ if (test_and_clear_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) {
nvme_cdev_del(&head->cdev, &head->cdev_device);
/*
* requeue I/O after NVME_NSHEAD_DISK_LIVE has been cleared
@@ -1006,6 +1008,12 @@ void nvme_mpath_shutdown_disk(struct nvme_ns_head *head)
kblockd_schedule_work(&head->requeue_work);
del_gendisk(head->disk);
}
+ /*
+ * 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);
}
void nvme_mpath_remove_disk(struct nvme_ns_head *head)
