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OpenCloudOS-Kernel/fs/dlm/midcomms.h

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 193 Based on 1 normalized pattern(s): this copyrighted material is made available to anyone wishing to use modify copy or redistribute it subject to the terms and conditions of the gnu general public license v 2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 45 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Richard Fontana <rfontana@redhat.com> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Steve Winslow <swinslow@gmail.com> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190528170027.342746075@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-29 00:57:20 +08:00
/* SPDX-License-Identifier: GPL-2.0-only */
[DLM] The core of the DLM for GFS2/CLVM This is the core of the distributed lock manager which is required to use GFS2 as a cluster filesystem. It is also used by CLVM and can be used as a standalone lock manager independantly of either of these two projects. It implements VAX-style locking modes. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steve Whitehouse <swhiteho@redhat.com>
2006-01-18 17:30:29 +08:00
/******************************************************************************
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
** Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved.
**
**
*******************************************************************************
******************************************************************************/
#ifndef __MIDCOMMS_DOT_H__
#define __MIDCOMMS_DOT_H__
fs: dlm: rework receive handling This patch reworks the current receive handling of dlm. As I tried to change the send handling to fix reorder issues I took a look into the receive handling and simplified it, it works as the following: Each connection has a preallocated receive buffer with a minimum length of 4096. On receive, the upper layer protocol will process all dlm message until there is not enough data anymore. If there exists "leftover" data at the end of the receive buffer because the dlm message wasn't fully received it will be copied to the begin of the preallocated receive buffer. Next receive more data will be appended to the previous "leftover" data and processing will begin again. This will remove a lot of code of the current mechanism. Inside the processing functionality we will ensure with a memmove() that the dlm message should be memory aligned. To have a dlm message always started at the beginning of the buffer will reduce some amount of memmove() calls because src and dest pointers are the same. The cluster attribute "buffer_size" becomes a new meaning, it's now the size of application layer receive buffer size. If this is changed during runtime the receive buffer will be reallocated. It's important that the receive buffer size has at minimum the size of the maximum possible dlm message size otherwise the received message cannot be placed inside the receive buffer size. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
2020-09-24 22:31:26 +08:00
int dlm_process_incoming_buffer(int nodeid, unsigned char *buf, int buflen);
fs: dlm: add more midcomms hooks This patch prepares hooks to redirect to the midcomms layer which will be used by the midcomms re-transmit handling. There exists the new concept of stateless buffers allocation and commits. This can be used to bypass the midcomms re-transmit handling. It is used by RCOM_STATUS and RCOM_NAMES messages, because they have their own ping-like re-transmit handling. As well these two messages will be used to determine the DLM version per node, because these two messages are per observation the first messages which are exchanged. Cluster manager events for node membership are added to add support for half-closed connections in cases that the peer connection get to an end of file but DLM still holds membership of the node. In this time DLM can still trigger new message which we should allow. After the cluster manager node removal event occurs it safe to close the connection. Signed-off-by: Alexander Aring <aahringo@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
2021-05-22 03:08:41 +08:00
struct dlm_mhandle *dlm_midcomms_get_mhandle(int nodeid, int len,
gfp_t allocation, char **ppc);
void dlm_midcomms_commit_mhandle(struct dlm_mhandle *mh);
int dlm_midcomms_close(int nodeid);
int dlm_midcomms_start(void);
void dlm_midcomms_shutdown(void);
void dlm_midcomms_add_member(int nodeid);
void dlm_midcomms_remove_member(int nodeid);
fs: dlm: add reliable connection if reconnect 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>
2021-05-22 03:08:46 +08:00
void dlm_midcomms_unack_msg_resend(int nodeid);
[DLM] The core of the DLM for GFS2/CLVM This is the core of the distributed lock manager which is required to use GFS2 as a cluster filesystem. It is also used by CLVM and can be used as a standalone lock manager independantly of either of these two projects. It implements VAX-style locking modes. Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steve Whitehouse <swhiteho@redhat.com>
2006-01-18 17:30:29 +08:00
#endif /* __MIDCOMMS_DOT_H__ */