drbd: protocol compatibility for maximum packet sizes
Two missing corner cases to the "maximum packet size" handshake.
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_nl.c b/drivers/block/drbd/drbd_nl.c
index 9ee4456..9ae33a5 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -861,6 +861,7 @@
struct inode *inode, *inode2;
struct lru_cache *resync_lru = NULL;
union drbd_state ns, os;
+ unsigned int max_seg_s;
int rv;
int cp_discovered = 0;
int logical_block_size;
@@ -1133,9 +1134,20 @@
mdev->read_cnt = 0;
mdev->writ_cnt = 0;
- drbd_setup_queue_param(mdev, mdev->state.conn == C_CONNECTED &&
- mdev->agreed_pro_version < 95 ?
- DRBD_MAX_SIZE_H80_PACKET : DRBD_MAX_SEGMENT_SIZE);
+ max_seg_s = DRBD_MAX_SEGMENT_SIZE;
+ if (mdev->state.conn == C_CONNECTED) {
+ /* We are Primary, Connected, and now attach a new local
+ * backing store. We must not increase the user visible maximum
+ * bio size on this device to something the peer may not be
+ * able to handle. */
+ if (mdev->agreed_pro_version < 94)
+ max_seg_s = queue_max_segment_size(mdev->rq_queue);
+ else if (mdev->agreed_pro_version == 94)
+ max_seg_s = DRBD_MAX_SIZE_H80_PACKET;
+ /* else: drbd 8.3.9 and later, stay with default */
+ }
+
+ drbd_setup_queue_param(mdev, max_seg_s);
/* If I am currently not R_PRIMARY,
* but meta data primary indicator is set,
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 6b69b2f..9da32ac 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -3088,6 +3088,8 @@
if (mdev->agreed_pro_version < 94)
max_seg_s = be32_to_cpu(p->max_segment_size);
+ else if (mdev->agreed_pro_version == 94)
+ max_seg_s = DRBD_MAX_SIZE_H80_PACKET;
else /* drbd 8.3.8 onwards */
max_seg_s = DRBD_MAX_SEGMENT_SIZE;