drbd: Introduce protocol version 100 headers
The 8 byte header finally becomes too small. With the protocol 100 header we
have 16 bit for the volume number, proper 32 bit for the data length, and
32 bit for further extensions in the future.
Previous versions of drbd are using version 80 headers for all packets
short enough for protocol 80. They support both header versions in
worker context, but only version 80 headers in asynchronous context.
For backwards compatibility, continue to use version 80 headers for
short packets before protocol version 100.
From protocol version 100 on, use the same header version for all
packets.
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_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 7e0ab22..311b9545 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -983,8 +983,18 @@
{
unsigned int header_size = drbd_header_size(tconn);
- if (header_size == sizeof(struct p_header95) &&
- *(__be16 *)header == cpu_to_be16(DRBD_MAGIC_BIG)) {
+ if (header_size == sizeof(struct p_header100) &&
+ *(__be32 *)header == cpu_to_be32(DRBD_MAGIC_100)) {
+ struct p_header100 *h = header;
+ if (h->pad != 0) {
+ conn_err(tconn, "Header padding is not zero\n");
+ return -EINVAL;
+ }
+ pi->vnr = be16_to_cpu(h->volume);
+ pi->cmd = be16_to_cpu(h->command);
+ pi->size = be32_to_cpu(h->length);
+ } else if (header_size == sizeof(struct p_header95) &&
+ *(__be16 *)header == cpu_to_be16(DRBD_MAGIC_BIG)) {
struct p_header95 *h = header;
pi->cmd = be16_to_cpu(h->command);