nbd: update size when connected

I messed up changing the size of an NBD device while it was connected by
not actually updating the device or doing the uevent.  Fix this by
updating everything if we're connected and we change the size.

cc: stable@vger.kernel.org
Fixes: 639812a1 ("nbd: don't set the device size until we're connected")
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

drivers/block/nbd.c

@@ -246,6 +246,8 @@ static void nbd_size_set(struct nbd_device *nbd, loff_t blocksize,
 	struct nbd_config *config = nbd->config;
 	config->blksize = blocksize;
 	config->bytesize = blocksize * nr_blocks;
+	if (nbd->task_recv != NULL)
+		nbd_size_update(nbd);
 }
 
 static void nbd_complete_rq(struct request *req)