[PATCH 2/2] nvme: delete disk when last path is gone

[Keith Busch]

On Thu, Feb 25, 2021 at 12:05:34PM +0100, Hannes Reinecke wrote:
> The multipath code currently deletes the disk only after all references
> to it are dropped rather than when the last path to that disk is lost.
> This differs from the behaviour in the non-multipathed case where the
> disk is deleted once the controller is removed.
> This has been reported to cause problems with some use cases like MD RAID.
> 
> This patch implements an alternative behaviour of deleting the disk when
> the last path is gone, ie the same behaviour as non-multipathed nvme
> devices. The alternative behaviour can be enabled with the new sysfs
> attribute 'no_path_detach'.

This looks ok to me. I have heard from a few people that they expected
it to work this way with the option enabled, but I suppose we do need to
retain the old behavior as default.

Reviewed-by: Keith Busch <kbusch at kernel.org>