drbd: Allow attaching of a newly created device to any backing device

A newly created device was never exposed before, i.e. has a
exposed_data_uuid of 0. Then it is valid to attach to any current_uuid
of a backing device (of course also to a newly created one (4))

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index f4d3aff89aa18343db0ab00bcc8aeddcd536a21f..1b35c45c92b75d7f01fd3fcda7a861ae099b4c7e 100644 (file)
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -1662,7 +1662,7 @@ int drbd_adm_attach(struct sk_buff *skb, struct genl_info *info)
        }
 
        if (device->state.conn < C_CONNECTED &&
-           device->state.role == R_PRIMARY &&
+           device->state.role == R_PRIMARY && device->ed_uuid &&
            (device->ed_uuid & ~((u64)1)) != (nbc->md.uuid[UI_CURRENT] & ~((u64)1))) {
                drbd_err(device, "Can only attach to data with current UUID=%016llX\n",
                    (unsigned long long)device->ed_uuid);