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freebsd-nq/sys/cam/ctl/ctl_ha.h
Kenneth D. Merry 130f4520cb Add the CAM Target Layer (CTL). 
CTL is a disk and processor device emulation subsystem originally written
for Copan Systems under Linux starting in 2003.  It has been shipping in
Copan (now SGI) products since 2005.

It was ported to FreeBSD in 2008, and thanks to an agreement between SGI
(who acquired Copan's assets in 2010) and Spectra Logic in 2010, CTL is
available under a BSD-style license.  The intent behind the agreement was
that Spectra would work to get CTL into the FreeBSD tree.

Some CTL features:

 - Disk and processor device emulation.
 - Tagged queueing
 - SCSI task attribute support (ordered, head of queue, simple tags)
 - SCSI implicit command ordering support.  (e.g. if a read follows a mode
   select, the read will be blocked until the mode select completes.)
 - Full task management support (abort, LUN reset, target reset, etc.)
 - Support for multiple ports
 - Support for multiple simultaneous initiators
 - Support for multiple simultaneous backing stores
 - Persistent reservation support
 - Mode sense/select support
 - Error injection support
 - High Availability support (1)
 - All I/O handled in-kernel, no userland context switch overhead.

(1) HA Support is just an API stub, and needs much more to be fully
    functional.

ctl.c:			The core of CTL.  Command handlers and processing,
			character driver, and HA support are here.

ctl.h:			Basic function declarations and data structures.

ctl_backend.c,
ctl_backend.h:		The basic CTL backend API.

ctl_backend_block.c,
ctl_backend_block.h:	The block and file backend.  This allows for using
			a disk or a file as the backing store for a LUN.
			Multiple threads are started to do I/O to the
			backing device, primarily because the VFS API
			requires that to get any concurrency.

ctl_backend_ramdisk.c:	A "fake" ramdisk backend.  It only allocates a
			small amount of memory to act as a source and sink
			for reads and writes from an initiator.  Therefore
			it cannot be used for any real data, but it can be
			used to test for throughput.  It can also be used
			to test initiators' support for extremely large LUNs.

ctl_cmd_table.c:	This is a table with all 256 possible SCSI opcodes,
			and command handler functions defined for supported
			opcodes.

ctl_debug.h:		Debugging support.

ctl_error.c,
ctl_error.h:		CTL-specific wrappers around the CAM sense building
			functions.

ctl_frontend.c,
ctl_frontend.h:		These files define the basic CTL frontend port API.

ctl_frontend_cam_sim.c:	This is a CTL frontend port that is also a CAM SIM.
			This frontend allows for using CTL without any
			target-capable hardware.  So any LUNs you create in
			CTL are visible in CAM via this port.

ctl_frontend_internal.c,
ctl_frontend_internal.h:
			This is a frontend port written for Copan to do
			some system-specific tasks that required sending
			commands into CTL from inside the kernel.  This
			isn't entirely relevant to FreeBSD in general,
			but can perhaps be repurposed.

ctl_ha.h:		This is a stubbed-out High Availability API.  Much
			more is needed for full HA support.  See the
			comments in the header and the description of what
			is needed in the README.ctl.txt file for more
			details.

ctl_io.h:		This defines most of the core CTL I/O structures.
			union ctl_io is conceptually very similar to CAM's
			union ccb.

ctl_ioctl.h:		This defines all ioctls available through the CTL
			character device, and the data structures needed
			for those ioctls.

ctl_mem_pool.c,
ctl_mem_pool.h:		Generic memory pool implementation used by the
			internal frontend.

ctl_private.h:		Private data structres (e.g. CTL softc) and
			function prototypes.  This also includes the SCSI
			vendor and product names used by CTL.

ctl_scsi_all.c,
ctl_scsi_all.h:		CTL wrappers around CAM sense printing functions.

ctl_ser_table.c:	Command serialization table.  This defines what
			happens when one type of command is followed by
			another type of command.

ctl_util.c,
ctl_util.h:		CTL utility functions, primarily designed to be
			used from userland.  See ctladm for the primary
			consumer of these functions.  These include CDB
			building functions.

scsi_ctl.c:		CAM target peripheral driver and CTL frontend port.
			This is the path into CTL for commands from
			target-capable hardware/SIMs.

README.ctl.txt:		CTL code features, roadmap, to-do list.

usr.sbin/Makefile:	Add ctladm.

ctladm/Makefile,
ctladm/ctladm.8,
ctladm/ctladm.c,
ctladm/ctladm.h,
ctladm/util.c:		ctladm(8) is the CTL management utility.
			It fills a role similar to camcontrol(8).
			It allow configuring LUNs, issuing commands,
			injecting errors and various other control
			functions.

usr.bin/Makefile:	Add ctlstat.

ctlstat/Makefile
ctlstat/ctlstat.8,
ctlstat/ctlstat.c:	ctlstat(8) fills a role similar to iostat(8).
			It reports I/O statistics for CTL.

sys/conf/files:		Add CTL files.

sys/conf/NOTES:		Add device ctl.

sys/cam/scsi_all.h:	To conform to more recent specs, the inquiry CDB
			length field is now 2 bytes long.

			Add several mode page definitions for CTL.

sys/cam/scsi_all.c:	Handle the new 2 byte inquiry length.

sys/dev/ciss/ciss.c,
sys/dev/ata/atapi-cam.c,
sys/cam/scsi/scsi_targ_bh.c,
scsi_target/scsi_cmds.c,
mlxcontrol/interface.c:	Update for 2 byte inquiry length field.

scsi_da.h:		Add versions of the format and rigid disk pages
			that are in a more reasonable format for CTL.

amd64/conf/GENERIC,
i386/conf/GENERIC,
ia64/conf/GENERIC,
sparc64/conf/GENERIC:	Add device ctl.

i386/conf/PAE:		The CTL frontend SIM at least does not compile
			cleanly on PAE.

Sponsored by:	Copan Systems, SGI and Spectra Logic
MFC after:	1 month
2012-01-12 00:34:33 +00:00

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/*-
* Copyright (c) 2003-2009 Silicon Graphics International Corp.
* Copyright (c) 2011 Spectra Logic Corporation
* 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_SER_ONLY: Commands are serialized to the other side. Write
* mirroring and read re-direction are assumed to
* happen in the back end.
* CTL_HA_MODE_XFER: Commands are serialized and data is transferred
* for write mirroring and read re-direction.
*/
typedef enum {
CTL_HA_MODE_SER_ONLY,
CTL_HA_MODE_XFER
} ctl_ha_mode;
/*
* This is a stubbed out High Availability interface. It assumes two nodes
* staying in sync.
*
* The reason this interface is here, and stubbed out, is that CTL was
* originally written with support for Copan's (now SGI) high availability
* framework. That framework was not released by SGI, and would not have
* been generally applicable to FreeBSD anyway.
*
* The idea here is to show the kind of API that would need to be in place
* in a HA framework to work with CTL's HA hooks. This API is very close
* to the Copan/SGI API, so that the code using it could stay in place
* as-is.
*
* So, in summary, this is a shell without real substance, and much more
* work would be needed to actually make HA work. The implementation
* inside CTL will also need to change to fit the eventual implementation.
* The additional pieces we would need are:
*
* - HA "Supervisor" framework that can startup the components of the
* system, and initiate failover (i.e. active/active to single mode)
* and failback (single to active/active mode) state transitions.
* This framework would be able to recognize when an event happens
* that requires it to initiate state transitions in the components it
* manages.
*
* - HA communication framework. This framework should have the following
* features:
* - Separate channels for separate system components. The CTL
* instance on one node should communicate with the CTL instance
* on another node.
* - Short message passing. These messages would be fixed length, so
* they could be preallocated and easily passed between the nodes.
* i.e. conceptually like an ethernet packet.
* - DMA/large buffer capability. This would require some negotiation
* with the other node to define the destination. It could
* allow for "push" (i.e. initiated by the requesting node) DMA or
* "pull" (i.e. initiated by the target controller) DMA or both.
* - Communication channel status change notification.
* - HA capability in other portions of the storage stack. Having two CTL
* instances communicate is just one part of an overall HA solution.
* State needs to be synchronized at multiple levels of the system in
* order for failover to actually work. For instance, if CTL is using a
* file on a ZFS filesystem as its backing store, the ZFS array state
* should be synchronized with the other node, so that the other node
* can immediately take over if the node that is primary for a particular
* array fails.
*/
/*
* 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_NONE,
CTL_HA_CHAN_CTL,
CTL_HA_CHAN_ZFS,
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_MSG_SENT: Message sent to the other node.
* CTL_HA_EVT_DISCONNECT: Communication channel disconnected.
* CTL_HA_EVT_DMA_SENT: DMA successfully sent to other node (push).
* CTL_HA_EVT_DMA_RECEIVED: DMA successfully received by other node (pull).
*/
typedef enum {
CTL_HA_EVT_NONE,
CTL_HA_EVT_MSG_RECV,
CTL_HA_EVT_MSG_SENT,
CTL_HA_EVT_DISCONNECT,
CTL_HA_EVT_DMA_SENT,
CTL_HA_EVT_DMA_RECEIVED,
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_DATA_CTL,
CTL_HA_DATA_ZFS,
CTL_HA_DATA_MAX
} ctl_ha_dtid;
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;
ctl_ha_dtid id;
int ret;
uint32_t size;
uint8_t *local;
uint8_t *remote;
};
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);
static inline ctl_ha_status
ctl_ha_msg_create(ctl_ha_channel channel, ctl_evt_handler handler)
{
return (CTL_HA_STATUS_SUCCESS);
}
/*
* Receive a message of the specified size.
*/
static inline ctl_ha_status
ctl_ha_msg_recv(ctl_ha_channel channel, void *buffer, unsigned int size,
int wait)
{
return (CTL_HA_STATUS_SUCCESS);
}
/*
* Send a message of the specified size.
*/
static inline ctl_ha_status
ctl_ha_msg_send(ctl_ha_channel channel, void *buffer, unsigned int size,
int wait)
{
return (CTL_HA_STATUS_SUCCESS);
}
/*
* Allocate a data transfer request structure.
*/
static inline struct ctl_ha_dt_req *
ctl_dt_req_alloc(void)
{
return (NULL);
}
/*
* Free a data transfer request structure.
*/
static inline void
ctl_dt_req_free(struct ctl_ha_dt_req *req)
{
return;
}
/*
* Issue a DMA request for a single buffer.
*/
static inline ctl_ha_status
ctl_dt_single(struct ctl_ha_dt_req *req)
{
return (CTL_HA_STATUS_WAIT);
}
/*
* SINGLE: One node
* HA: Two nodes (Active/Active implied)
* SLAVE/MASTER: The component can set these flags to indicate which side
* is in control. It has no effect on the HA framework.
*/
typedef enum {
CTL_HA_STATE_UNKNOWN = 0x00,
CTL_HA_STATE_SINGLE = 0x01,
CTL_HA_STATE_HA = 0x02,
CTL_HA_STATE_MASK = 0x0F,
CTL_HA_STATE_SLAVE = 0x10,
CTL_HA_STATE_MASTER = 0x20
} ctl_ha_state;
typedef enum {
CTL_HA_COMP_STATUS_OK,
CTL_HA_COMP_STATUS_FAILED,
CTL_HA_COMP_STATUS_ERROR
} ctl_ha_comp_status;
struct ctl_ha_component;
typedef ctl_ha_comp_status (*ctl_hacmp_init_t)(struct ctl_ha_component *);
typedef ctl_ha_comp_status (*ctl_hacmp_start_t)(struct ctl_ha_component *,
ctl_ha_state);
struct ctl_ha_component {
char *name;
ctl_ha_state state;
ctl_ha_comp_status status;
ctl_hacmp_init_t init;
ctl_hacmp_start_t start;
ctl_hacmp_init_t quiesce;
};
#define CTL_HA_STATE_IS_SINGLE(state) ((state & CTL_HA_STATE_MASK) == \
CTL_HA_STATE_SINGLE)
#define CTL_HA_STATE_IS_HA(state) ((state & CTL_HA_STATE_MASK) == \
CTL_HA_STATE_HA)
#endif /* _CTL_HA_H_ */
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