On Tue, May 18, 2021 at 9:52 AM Prasanna Kalever [off-list ref] wrote:

quoted

BTW, loop has similar issue, and patch of 'block: add a sequence number to disks'
is added for addressing this issue, what do you think of that generic
approach wrt. this nbd's issue? such as used the exposed sysfs sequence number
for addressing this issue?

https://lore.kernel.org/linux-block/YH81n34d2G3C4Re+@gardel-login/#r (local)

If I understand the changes and the background of the fix correctly, I
think with that fix author is trying to monotonically increase the seq
number and add it to the disk on every single device map/attach and
expose it through the sysfs, which will help the userspace processes
further to correlate events for particular and specific devices that
reuse the same loop device.

Yes, but nothing prevents to use diskseq in nbd, and increase it on reconfigure.
That would allow to detect if the device has been reconfigured.

Regards,
-- 
per aspera ad upstream