[PATCH] nvme-multipath: clear NVME_NS_SYSFS_ATTR_LINK when disk is not added

[PATCH] nvme-multipath: clear NVME_NS_SYSFS_ATTR_LINK when disk is not added

[Hannes Reinecke]

If the namespace disk is not added we need to clear NVME_NS_SYSFS_ATTR_LINK,
otherwise the link will never be created upon rescan.

Fixes: 4dbd2b2ebe4c ("nvme-multipath: Add visibility for round-robin io-policy")

Signed-off-by: Hannes Reinecke <hare@kernel.org>
Cc: Nilay Shroff <nilay@linux.ibm.com>
---
 drivers/nvme/host/multipath.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 05eccd96d34a..5c28f0dc6fad 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -1069,8 +1069,10 @@ void nvme_mpath_add_sysfs_link(struct nvme_ns_head *head)
 		 * Ensure that ns path disk node is already added otherwise we
 		 * may get invalid kobj name for target
 		 */
-		if (!test_bit(GD_ADDED, &ns->disk->state))
+		if (!test_bit(GD_ADDED, &ns->disk->state)) {
+			clear_bit(NVME_NS_SYSFS_ATTR_LINK, &ns->flags);
 			continue;
+		}
 
 		target = disk_to_dev(ns->disk);
 		/*
-- 
2.35.3

Re: [PATCH] nvme-multipath: clear NVME_NS_SYSFS_ATTR_LINK when disk is not added

[Sagi Grimberg]

On 14/04/2025 15:25, Hannes Reinecke wrote:
> If the namespace disk is not added we need to clear NVME_NS_SYSFS_ATTR_LINK,
> otherwise the link will never be created upon rescan.
>
> Fixes: 4dbd2b2ebe4c ("nvme-multipath: Add visibility for round-robin io-policy")
>
> Signed-off-by: Hannes Reinecke <hare@kernel.org>
> Cc: Nilay Shroff <nilay@linux.ibm.com>
> ---
>   drivers/nvme/host/multipath.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index 05eccd96d34a..5c28f0dc6fad 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -1069,8 +1069,10 @@ void nvme_mpath_add_sysfs_link(struct nvme_ns_head *head)
>   		 * Ensure that ns path disk node is already added otherwise we
>   		 * may get invalid kobj name for target
>   		 */
> -		if (!test_bit(GD_ADDED, &ns->disk->state))
> +		if (!test_bit(GD_ADDED, &ns->disk->state)) {
> +			clear_bit(NVME_NS_SYSFS_ATTR_LINK, &ns->flags);
>   			continue;
> +		}
>   
>   		target = disk_to_dev(ns->disk);
>   		/*

Why not change the ordering of GD_ADDED and NVME_NS_SYSFS_ATTR_LINK checks?

Re: [PATCH] nvme-multipath: clear NVME_NS_SYSFS_ATTR_LINK when disk is not added

[Nilay Shroff]

On 4/15/25 2:02 AM, Sagi Grimberg wrote:
> 
> 
> On 14/04/2025 15:25, Hannes Reinecke wrote:
>> If the namespace disk is not added we need to clear NVME_NS_SYSFS_ATTR_LINK,
>> otherwise the link will never be created upon rescan.
>>
>> Fixes: 4dbd2b2ebe4c ("nvme-multipath: Add visibility for round-robin io-policy")
>>
>> Signed-off-by: Hannes Reinecke <hare@kernel.org>
>> Cc: Nilay Shroff <nilay@linux.ibm.com>
>> ---
>>   drivers/nvme/host/multipath.c | 4 +++-
>>   1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
>> index 05eccd96d34a..5c28f0dc6fad 100644
>> --- a/drivers/nvme/host/multipath.c
>> +++ b/drivers/nvme/host/multipath.c
>> @@ -1069,8 +1069,10 @@ void nvme_mpath_add_sysfs_link(struct nvme_ns_head *head)
>>            * Ensure that ns path disk node is already added otherwise we
>>            * may get invalid kobj name for target
>>            */
>> -        if (!test_bit(GD_ADDED, &ns->disk->state))
>> +        if (!test_bit(GD_ADDED, &ns->disk->state)) {
>> +            clear_bit(NVME_NS_SYSFS_ATTR_LINK, &ns->flags);
>>               continue;
>> +        }
>>             target = disk_to_dev(ns->disk);
>>           /*
> 
> Why not change the ordering of GD_ADDED and NVME_NS_SYSFS_ATTR_LINK checks?

This is exactly same issue I also encountered last week while unit testing 
changes while adding support for this feature in libnvme. Then I fixed it 
locally and queued it up for upstream. But anyways, I'm glad that you already
fixed it and send the fix upstream :) 

However my changes were exactly same as Sagi suggested. I just changed the 
order of setting NVME_NS_SYSFS_ATTR_LINK and GD_ADDED. So I also recommend
we may just switch the order and fix it.

Thanks,
--Nilay