drbd: attach on connected diskless peer must not shrink a consistent device

If we would reject a new handshake, if the peer had attached first,
and then connected, we should force disconnect if the peer first connects,
and only then attaches.

Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 0a9f3c65f70adc46bcd3cfc5ca42829a8a7c80d5..85e3d846a23aec5dac62808caa8dde16b6157211 100644 (file)
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -4014,12 +4014,13 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
                if (device->state.conn == C_WF_REPORT_PARAMS)
                        p_usize = min_not_zero(my_usize, p_usize);
 
-               /* Never shrink a device with usable data during connect.
-                  But allow online shrinking if we are connected. */
+               /* Never shrink a device with usable data during connect,
+                * or "attach" on the peer.
+                * But allow online shrinking if we are connected. */
                new_size = drbd_new_dev_size(device, device->ldev, p_usize, 0);
                if (new_size < cur_size &&
                    device->state.disk >= D_OUTDATED &&
-                   device->state.conn < C_CONNECTED) {
+                   (device->state.conn < C_CONNECTED || device->state.pdsk == D_DISKLESS)) {
                        drbd_err(device, "The peer's disk size is too small! (%llu < %llu sectors)\n",
                                        (unsigned long long)new_size, (unsigned long long)cur_size);
                        conn_request_state(peer_device->connection, NS(conn, C_DISCONNECTING), CS_HARD);
@@ -4047,8 +4048,8 @@ static int receive_sizes(struct drbd_connection *connection, struct packet_info
                        synchronize_rcu();
                        kfree(old_disk_conf);
 
-                       drbd_info(device, "Peer sets u_size to %lu sectors\n",
-                                (unsigned long)my_usize);
+                       drbd_info(device, "Peer sets u_size to %lu sectors (old: %lu)\n",
+                                (unsigned long)p_usize, (unsigned long)my_usize);
                }
 
                put_ldev(device);