[PATCH 0/1] RFC: implement reopen for nbd driver

[Maxim Levitsky]

Hi,
It looks like nbd driver doesn't have support
for reopen, which doesn't allow to commit qcow2 snapshots
which have nbd export as a base file.
This is because the base is opened read-only, and only
when commit job starts it reopens the base read-write.

Now after talking with Eric Blake, I understood that
nbd doesn't have the ability to tell the server to open read/only
and then change this on the fly, thus even when opening
an export as read-only the server will still allow writes.

This means that an empty .bdrv_reopen_prepare
(well except checking that export is not read-only) is supposed
to be enough.

Sending this as RFC, since I am not sure that this is the correct
solution.

Best regards,
        Maxim Levitsky

Maxim Levitsky (1):
  nbd: add empty .bdrv_reopen_prepare

 block/nbd.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

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2.17.2