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(+)
--
2.17.2
