freebsd-dev/sys/cam/ctl/ctl_ha.h
Alexander Motin 7ac58230ea Reimplement CTL High Availability.
CTL HA functionality was originally implemented by Copan many years ago,
but large part of the sources was never published.  This change includes
clean room implementation of the missing code and fixes for many bugs.

This code supports dual-node HA with ALUA in four modes:
 - Active/Unavailable without interlink between nodes;
 - Active/Standby with second node handling only basic LUN discovery and
reservation, synchronizing with the first node through the interlink;
 - Active/Active with both nodes processing commands and accessing the
backing storage, synchronizing with the first node through the interlink;
 - Active/Active with second node working as proxy, transfering all
commands to the first node for execution through the interlink.

Unlike original Copan's implementation, depending on specific hardware,
this code uses simple custom TCP-based protocol for interlink.  It has
no authentication, so it should never be enabled on public interfaces.

The code may still need some polishing, but generally it is functional.

Relnotes:	yes
Sponsored by:	iXsystems, Inc.
2015-09-10 12:40:31 +00:00

140 lines
4.3 KiB
C

/*-
* Copyright (c) 2003-2009 Silicon Graphics International Corp.
* Copyright (c) 2011 Spectra Logic Corporation
* Copyright (c) 2015 Alexander Motin <mav@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*
* $Id: //depot/users/kenm/FreeBSD-test2/sys/cam/ctl/ctl_ha.h#1 $
* $FreeBSD$
*/
#ifndef _CTL_HA_H_
#define _CTL_HA_H_
/*
* CTL High Availability Modes:
*
* CTL_HA_MODE_ACT_STBY: Commands are serialized to the master side.
* No media access commands on slave side (Standby).
* CTL_HA_MODE_SER_ONLY: Commands are serialized to the master side.
* Media can be accessed on both sides.
* CTL_HA_MODE_XFER: Commands and data are forwarded to the
* master side for execution.
*/
typedef enum {
CTL_HA_MODE_ACT_STBY,
CTL_HA_MODE_SER_ONLY,
CTL_HA_MODE_XFER
} ctl_ha_mode;
/*
* Communication channel IDs for various system components. This is to
* make sure one CTL instance talks with another, one ZFS instance talks
* with another, etc.
*/
typedef enum {
CTL_HA_CHAN_CTL,
CTL_HA_CHAN_DATA,
CTL_HA_CHAN_MAX
} ctl_ha_channel;
/*
* HA communication event notification. These are events generated by the
* HA communication subsystem.
*
* CTL_HA_EVT_MSG_RECV: Message received by the other node.
* CTL_HA_EVT_LINK_CHANGE: Communication channel status changed.
*/
typedef enum {
CTL_HA_EVT_NONE,
CTL_HA_EVT_MSG_RECV,
CTL_HA_EVT_LINK_CHANGE,
CTL_HA_EVT_MAX
} ctl_ha_event;
typedef enum {
CTL_HA_STATUS_WAIT,
CTL_HA_STATUS_SUCCESS,
CTL_HA_STATUS_ERROR,
CTL_HA_STATUS_INVALID,
CTL_HA_STATUS_DISCONNECT,
CTL_HA_STATUS_BUSY,
CTL_HA_STATUS_MAX
} ctl_ha_status;
typedef enum {
CTL_HA_DT_CMD_READ,
CTL_HA_DT_CMD_WRITE,
} ctl_ha_dt_cmd;
struct ctl_ha_dt_req;
typedef void (*ctl_ha_dt_cb)(struct ctl_ha_dt_req *);
struct ctl_ha_dt_req {
ctl_ha_dt_cmd command;
void *context;
ctl_ha_dt_cb callback;
int ret;
uint32_t size;
uint8_t *local;
uint8_t *remote;
TAILQ_ENTRY(ctl_ha_dt_req) links;
};
struct ctl_softc;
ctl_ha_status ctl_ha_msg_init(struct ctl_softc *softc);
ctl_ha_status ctl_ha_msg_shutdown(struct ctl_softc *softc);
typedef void (*ctl_evt_handler)(ctl_ha_channel channel, ctl_ha_event event,
int param);
void ctl_ha_register_evthandler(ctl_ha_channel channel,
ctl_evt_handler handler);
ctl_ha_status ctl_ha_msg_register(ctl_ha_channel channel,
ctl_evt_handler handler);
ctl_ha_status ctl_ha_msg_recv(ctl_ha_channel channel, void *addr,
size_t len, int wait);
ctl_ha_status ctl_ha_msg_send(ctl_ha_channel channel, const void *addr,
size_t len, int wait);
ctl_ha_status ctl_ha_msg_send2(ctl_ha_channel channel, const void *addr,
size_t len, const void *addr2, size_t len2, int wait);
ctl_ha_status ctl_ha_msg_deregister(ctl_ha_channel channel);
struct ctl_ha_dt_req * ctl_dt_req_alloc(void);
void ctl_dt_req_free(struct ctl_ha_dt_req *req);
ctl_ha_status ctl_dt_single(struct ctl_ha_dt_req *req);
typedef enum {
CTL_HA_LINK_OFFLINE = 0x00,
CTL_HA_LINK_UNKNOWN = 0x01,
CTL_HA_LINK_ONLINE = 0x02
} ctl_ha_link_state;
#endif /* _CTL_HA_H_ */