The wire protocol is no longer a property that is negotiated
between the two peers. It is now expressed with two bits
(DP_SEND_WRITE_ACK and DP_SEND_RECEIVE_ACK) in each data
packet. Therefore the primary node is free to change the
wire protocol at any time without disconnect/reconnect.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
With this commit the locking for all accesses to IDRs is complete:
* Non sleeping read accesses are protected by RCU
* sleeping read accesses are protocted by a read lock on drbd_cfg_rwsem
* accesses that add anything are protected by a write lock
* accesses that remove an object are protoected by a write lock
and a call to synchronize_rcu() after it is removed from the IDR
and before the object is actually free()ed.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Since have now header 100, that has space for 16 bit volume numbers,
the high byte of the length in header 95 is no longer reserved for
8 bit volume numbers.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
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>
Prepare the introduction of the protocol 100 headers. The actual protocol
header is removed for the packet declarations. I.e. allow us to use the
packets with different headers.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Centralize sock->mutex locking and unlocking in [drbd|conn]_prepare_command()
and [drbd|conn]_send_comman().
Therefore all *_send_* functions are touched to use these primitives instead
of drbd_get_data_sock()/drbd_put_data_sock() and former helper functions.
That change makes the *_send_* functions more standardized.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Packets of type P_HAND_SHAKE define which protocol versions and features
a node supports. For clarity, call those packets P_CONNECTION_FEATURES
instead.
(This does not determine the features that a specific drbd device
supports, such as drbd protocol A, B, C.)
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
The first packets exchanged when a connection is established are
referred to as P_HAND_SHAKE_S and P_HAND_SHAKE_M in the code, followed
by P_HAND_SHAKE packets. To avoid confusion between these two unrelated
things, call the initial packets P_INITIAL_DATA and P_INITIAL_META.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
There is no need to send protocol 80 headers to peers that understand
protocol 95 headers. Make sure that we don't send protocol 95 headers
until we have agreed upon a protocol version with our peer, though.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This helps to ensure that we don't miss one of them when changing their
return value semantics.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
