drbd: Improve compatibility with drbd's older than 8.3.7
Regression introduced with 8.3.11 commit:
drbd: Take a more conservative approach when deciding max_bio_size
Never ever tell an older drbd, that we support more than 32KiB
in a single data request (packet).
Never believe an older drbd, that is supports more than 32KiB
in a single data request (packet)
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 8e83a40..a15135b 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2112,6 +2112,10 @@
max_bio_size = DRBD_MAX_BIO_SIZE; /* ... multiple BIOs per peer_request */
}
+ /* Never allow old drbd (up to 8.3.7) to see more than 32KiB */
+ if (mdev->agreed_pro_version <= 94)
+ max_bio_size = min_t(int, max_bio_size, DRBD_MAX_SIZE_H80_PACKET);
+
p.d_size = cpu_to_be64(d_size);
p.u_size = cpu_to_be64(u_size);
p.c_size = cpu_to_be64(trigger_reply ? 0 : drbd_get_capacity(mdev->this_bdev));