On 11/9/20 9:53 AM, Christoph Hellwig wrote:
On Mon, Nov 09, 2020 at 08:53:58AM +0100, Hannes Reinecke wrote:
index 376096bfc54a83..4e86c9aafd88a7 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2053,7 +2053,7 @@ static void nvme_update_disk_info(struct gendisk *disk,
capacity = 0;
[ .. ]
Originally nvme multipath would update/change the size of the multipath
device according to the underlying path devices.
With this patch the size of the multipath device will _not_ change if there
is a change on the underlying devices.
Yes, it will. Take a close look at nvme_update_disk_info and how it is
called.
Okay, then: What would be the correct way of handling a size update for
NVMe multipath?
Assuming we're getting an AEN for each path signalling the size change
(or a controller reset leading to a size change).
So if we're updating the size of the multipath device together with the
path device at the first AEN/reset we'll end up with the other paths
having a different size than the multipath device (and the path we've
just been updating).
- Do we care, or cross fingers and hope for the best?
- Shouldn't we detect the case where we won't get a size update for the
other paths, or, indeed, we have a genuine device size mismatch due to a
misconfiguration on the target?
IE shouldn't we have a flag 'size update pending' for the other paths,,
to take them out ouf use temporarily until the other AENs/resets have
been processed?
Cheers,
Hannes
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Dr. Hannes Reinecke Kernel Storage Architect
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