* [PATCHv3] nvme: allow to re-attach namespaces after all paths are down
@ 2021-05-11 7:59 Hannes Reinecke
2021-05-11 16:26 ` Christoph Hellwig
0 siblings, 1 reply; 3+ messages in thread
From: Hannes Reinecke @ 2021-05-11 7:59 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: Sagi Grimberg, Keith Busch, linux-nvme, Hannes Reinecke
We should only remove the ns head from the list of heads per
subsystem if the reference count drops to zero. Removing it
at the start of nvme_ns_remove() will prevent us from reattaching
the namespace to the correct ns head once a path becomes available
again.
Changes to v2:
- Drop memcpy() statement
Changes to v1:
- Always check NSIDs after reattach
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
drivers/nvme/host/core.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 522c9b229f80..6a5386267c10 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -546,6 +546,9 @@ static void nvme_free_ns_head(struct kref *ref)
struct nvme_ns_head *head =
container_of(ref, struct nvme_ns_head, ref);
+ mutex_lock(&head->subsys->lock);
+ list_del_init(&head->entry);
+ mutex_unlock(&head->subsys->lock);
nvme_mpath_remove_disk(head);
ida_simple_remove(&head->subsys->ns_ida, head->instance);
cleanup_srcu_struct(&head->srcu);
@@ -3605,15 +3608,23 @@ static int nvme_init_ns_head(struct nvme_ns *ns, unsigned nsid,
head->shared = is_shared;
} else {
ret = -EINVAL;
+ /*
+ * If multipath is enabled we might hit an ns head with no
+ * paths, but that doesn't indicate it's a shared namespace.
+ */
+ if (nvme_ns_head_multipath(head) &&
+ list_empty(&head->list))
+ goto check_ids;
if (!is_shared || !head->shared) {
dev_err(ctrl->device,
"Duplicate unshared namespace %d\n", nsid);
goto out_put_ns_head;
}
+check_ids:
if (!nvme_ns_ids_equal(&head->ids, ids)) {
dev_err(ctrl->device,
"IDs don't match for shared namespace %d\n",
- nsid);
+ nsid);
goto out_put_ns_head;
}
}
@@ -3764,8 +3775,6 @@ 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 */
--
2.29.2
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^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCHv3] nvme: allow to re-attach namespaces after all paths are down
2021-05-11 7:59 [PATCHv3] nvme: allow to re-attach namespaces after all paths are down Hannes Reinecke
@ 2021-05-11 16:26 ` Christoph Hellwig
2021-05-12 5:28 ` Hannes Reinecke
0 siblings, 1 reply; 3+ messages in thread
From: Christoph Hellwig @ 2021-05-11 16:26 UTC (permalink / raw)
To: Hannes Reinecke; +Cc: Christoph Hellwig, Sagi Grimberg, Keith Busch, linux-nvme
> } else {
> ret = -EINVAL;
> + /*
> + * If multipath is enabled we might hit an ns head with no
> + * paths, but that doesn't indicate it's a shared namespace.
> + */
> + if (nvme_ns_head_multipath(head) &&
> + list_empty(&head->list))
> + goto check_ids;
> if (!is_shared || !head->shared) {
> dev_err(ctrl->device,
> "Duplicate unshared namespace %d\n", nsid);
> goto out_put_ns_head;
> }
> +check_ids:
I think this should simply be:
if (!list_empty(&head->list) && (!is_shared || !head->shared)) {
dev_err(ctrl->device,
"Duplicate unshared namespace %d\n", nsid);
goto out_put_ns_head;
}
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCHv3] nvme: allow to re-attach namespaces after all paths are down
2021-05-11 16:26 ` Christoph Hellwig
@ 2021-05-12 5:28 ` Hannes Reinecke
0 siblings, 0 replies; 3+ messages in thread
From: Hannes Reinecke @ 2021-05-12 5:28 UTC (permalink / raw)
To: Christoph Hellwig; +Cc: Sagi Grimberg, Keith Busch, linux-nvme
On 5/11/21 6:26 PM, Christoph Hellwig wrote:
>> } else {
>> ret = -EINVAL;
>> + /*
>> + * If multipath is enabled we might hit an ns head with no
>> + * paths, but that doesn't indicate it's a shared namespace.
>> + */
>> + if (nvme_ns_head_multipath(head) &&
>> + list_empty(&head->list))
>> + goto check_ids;
>> if (!is_shared || !head->shared) {
>> dev_err(ctrl->device,
>> "Duplicate unshared namespace %d\n", nsid);
>> goto out_put_ns_head;
>> }
>> +check_ids:
>
> I think this should simply be:
>
> if (!list_empty(&head->list) && (!is_shared || !head->shared)) {
> dev_err(ctrl->device,
> "Duplicate unshared namespace %d\n", nsid);
> goto out_put_ns_head;
> }
>
I wasn't sure if this isn't just for multipathing; other setups can't
queue I/O, so we'll be hitting this scenario only in the unlikely case
that the device is removed _and re-attached_ without any I/O pending.
Hence the check.
But sure, I can modify it.
Cheers,
Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@suse.de +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer
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^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-05-12 5:29 UTC | newest]
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2021-05-11 7:59 [PATCHv3] nvme: allow to re-attach namespaces after all paths are down Hannes Reinecke
2021-05-11 16:26 ` Christoph Hellwig
2021-05-12 5:28 ` Hannes Reinecke
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