This patch renames DEFAULT_BUFFER_SIZE to DLM_MAX_SOCKET_BUFSIZE and LOWCOMMS_MAX_TX_BUFFER_LEN to DLM_MAX_APP_BUFSIZE as they are proper names to define what's behind those values. The DLM_MAX_SOCKET_BUFSIZE defines the maximum size of buffer which can be handled on socket layer, the DLM_MAX_APP_BUFSIZE defines the maximum size of buffer which can be handled by the DLM application layer. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
Currently the dlm protocol values are that TCP is 0 and everything else is SCTP. This makes it difficult to introduce possible other transport layers. The only one user space tool dlm_controld, which I am aware of, handles the protocol value 1 for SCTP. We change it now to handle SCTP as 1, this will break user space API but it will fix it so we can add possible other transport layers. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
This patch checks if possible allowing new connections is allowed before queueing the listen socket to accept new connections. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
The proper way to allocate ordered workqueues is to use alloc_ordered_workqueue() function. The current way implies an ordered workqueue which is also required by dlm. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
This patch fixes the error path handling in lowcomms_start(). We need to cleanup some static allocated data structure and cleanup possible workqueue if these have started. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
This patch will clean a dirty page buffer if a reconnect occurs. If a page buffer was half transmitted we cannot start inside the middle of a dlm message if a node connects again. I observed invalid length receptions errors and was guessing that this behaviour occurs, after this patch I never saw an invalid message length again. This patch might drops more messages for dlm version 3.1 but 3.1 can't deal with half messages as well, for 3.2 it might trigger more re-transmissions but will not leave dlm in a broken state. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
This patch introduce to make a tcp lowcomms connection reliable even if reconnects occurs. This is done by an application layer re-transmission handling and sequence numbers in dlm protocols. There are three new dlm commands: DLM_OPTS: This will encapsulate an existing dlm message (and rcom message if they don't have an own application side re-transmission handling). As optional handling additional tlv's (type length fields) can be appended. This can be for example a sequence number field. However because in DLM_OPTS the lockspace field is unused and a sequence number is a mandatory field it isn't made as a tlv and we put the sequence number inside the lockspace id. The possibility to add optional options are still there for future purposes. DLM_ACK: Just a dlm header to acknowledge the receive of a DLM_OPTS message to it's sender. DLM_FIN: This provides a 4 way handshake for connection termination inclusive support for half-closed connections. It's provided on application layer because SCTP doesn't support half-closed sockets, the shutdown() call can interrupted by e.g. TCP resets itself and a hard logic to implement it because the othercon paradigm in lowcomms. The 4-way termination handshake also solve problems to synchronize peer EOF arrival and that the cluster manager removes the peer in the node membership handling of DLM. In some cases messages can be still transmitted in this time and we need to wait for the node membership event. To provide a reliable connection the node will retransmit all unacknowledges message to it's peer on reconnect. The receiver will then filtering out the next received message and drop all messages which are duplicates. As RCOM_STATUS and RCOM_NAMES messages are the first messages which are exchanged and they have they own re-transmission handling, there exists logic that these messages must be first. If these messages arrives we store the dlm version field. This handling is on DLM 3.1 and after this patch 3.2 the same. A backwards compatibility handling has been added which seems to work on tests without tcpkill, however it's not recommended to use DLM 3.1 and 3.2 at the same time, because DLM 3.2 tries to fix long term bugs in the DLM protocol. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
This patch moves out some lowcomms hash functionality into lowcomms header to provide them to other layers like midcomms as well. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
This patch introduces a retransmit functionality for a lowcomms message handle. It's just allocates a new buffer and transmit it again, no special handling about prioritize it because keeping bytestream in order. To avoid another connection look some refactor was done to make a new buffer allocation with a preexisting connection pointer. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
This patch makes the void pointer handle for lowcomms functionality per message and not per page allocation entry. A refcount handling for the handle was added to keep the message alive until the user doesn't need it anymore. There exists now a per message callback which will be called when allocating a new buffer. This callback will be guaranteed to be called according the order of the sending buffer, which can be used that the caller increments a sequence number for the dlm message handle. For transition process we cast the dlm_mhandle to dlm_msg and vice versa until the midcomms layer will implement a specific dlm_mhandle structure. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>