/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* stackglue.h
*
* Glue to the underlying cluster stack.
*
* Copyright (C) 2007 Oracle. All rights reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation, version 2.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#ifndef STACKGLUE_H
#define STACKGLUE_H
#include <linux/types.h>
#include <linux/list.h>
#include <linux/dlmconstants.h>
#include "dlm/dlmapi.h"
#include <linux/dlm.h>
/*
* dlmconstants.h does not have a LOCAL flag. We hope to remove it
* some day, but right now we need it. Let's fake it. This value is larger
* than any flag in dlmconstants.h.
*/
#define DLM_LKF_LOCAL 0x00100000
/*
* This shadows DLM_LOCKSPACE_LEN in fs/dlm/dlm_internal.h. That probably
* wants to be in a public header.
*/
#define GROUP_NAME_MAX 64
/*
* ocfs2_protocol_version changes when ocfs2 does something different in
* its inter-node behavior. See dlmglue.c for more information.
*/
struct ocfs2_protocol_version {
u8 pv_major;
u8 pv_minor;
};
/*
* The ocfs2_locking_protocol defines the handlers called on ocfs2's behalf.
*/
struct ocfs2_locking_protocol {
struct ocfs2_protocol_version lp_max_version;
void (*lp_lock_ast)(void *astarg);
void (*lp_blocking_ast)(void *astarg, int level);
void (*lp_unlock_ast)(void *astarg, int error);
};
/*
* The dlm_lockstatus struct includes lvb space, but the dlm_lksb struct only
* has a pointer to separately allocated lvb space. This struct exists only to
* include in the lksb union to make space for a combined dlm_lksb and lvb.
*/
struct fsdlm_lksb_plus_lvb {
struct dlm_lksb lksb;
char lvb[DLM_LVB_LEN];
};
/*
* A union of all lock status structures. We define it here so that the
* size of the union is known. Lock status structures are embedded in
* ocfs2 inodes.
*/
union ocfs2_dlm_lksb {
struct dlm_lockstatus lksb_o2dlm;
struct dlm_lksb lksb_fsdlm;
struct fsdlm_lksb_plus_lvb padding;
};
/*
* A cluster connection. Mostly opaque to ocfs2, the connection holds
* state for the underlying stack. ocfs2 does use cc_version to determine
* locking compatibility.
*/
struct ocfs2_cluster_connection {
char cc_name[GROUP_NAME_MAX];
int cc_namelen;
struct ocfs2_protocol_version cc_version;
void (*cc_recovery_handler)(int node_num, void *recovery_data);
void *cc_recovery_data;
void *cc_lockspace;
void *cc_private;
};
/*
* Each cluster stack implements the stack operations structure. Not used
* in the ocfs2 code, the stackglue code translates generic cluster calls
* into stack operations.
*/
struct ocfs2_stack_operations {
/*
* The fs code calls ocfs2_cluster_connect() to attach a new
* filesystem to the cluster stack. The ->connect() op is passed
* an ocfs2_cluster_connection with the name and recovery field
* filled in.
*
* The stack must set up any notification mechanisms and create
* the filesystem lockspace in the DLM. The lockspace should be
* stored on cc_lockspace. Any other information can be stored on
* cc_private.
*
* ->connect() must not return until it is guaranteed that
*
* - Node down notifications for the filesystem will be recieved
* and passed to conn->cc_recovery_handler().
* - Locking requests for the filesystem will be processed.
*/
int (*connect)(struct ocfs2_cluster_connection *conn);
/*
* The fs code calls ocfs2_cluster_disconnect() when a filesystem
* no longer needs cluster services. All DLM locks have been
* dropped, and recovery notification is being ignored by the
* fs code. The stack must disengage from the DLM and discontinue
* recovery notification.
*
* Once ->disconnect() has returned, the connection structure will
* be freed. Thus, a stack must not return from ->disconnect()
* until it will no longer reference the conn pointer.
*
* Once this call returns, the stack glue will be dropping this
* connection's reference on the module.
*/
int (*disconnect)(struct ocfs2_cluster_connection *conn);
/*
* ->this_node() returns the cluster's unique identifier for the
* local node.
*/
int (*this_node)(unsigned int *node);
/*
* Call the underlying dlm lock function. The ->dlm_lock()
* callback should convert the flags and mode as appropriate.
*
* ast and bast functions are not part of the call because the
* stack will likely want to wrap ast and bast calls before passing
* them to stack->sp_proto.
*/
int (*dlm_lock)(struct ocfs2_cluster_connection *conn,
int mode,
union ocfs2_dlm_lksb *lksb,
u32 flags,
void *name,
unsigned int namelen,
void *astarg);
/*
* Call the underlying dlm unlock function. The ->dlm_unlock()
* function should convert the flags as appropriate.
*
* The unlock ast is not passed, as the stack will want to wrap
* it before calling stack->sp_proto->lp_unlock_ast().
*/
int (*dlm_unlock)(struct ocfs2_cluster_connection *conn,
union ocfs2_dlm_lksb *lksb,
u32 flags,
void *astarg);
/*
* Return the status of the current lock status block. The fs
* code should never dereference the union. The ->lock_status()
* callback pulls out the stack-specific lksb, converts the status
* to a proper errno, and returns it.
*/
int (*lock_status)(union ocfs2_dlm_lksb *lksb);
/*
* Pull the lvb pointer off of the stack-specific lksb.
*/
void *(*lock_lvb)(union ocfs2_dlm_lksb *lksb);
/*
* This is an optoinal debugging hook. If provided, the
* stack can dump debugging information about this lock.
*/
void (*dump_lksb)(union ocfs2_dlm_lksb *lksb);
};
/*
* Each stack plugin must describe itself by registering a
* ocfs2_stack_plugin structure. This is only seen by stackglue and the
* stack driver.
*/
struct ocfs2_stack_plugin {
char *sp_name;
struct ocfs2_stack_operations *sp_ops;
struct module *sp_owner;
/* These are managed by the stackglue code. */
struct list_head sp_list;
unsigned int sp_count;
struct ocfs2_locking_protocol *sp_proto;
};
/* Used by the filesystem */
int ocfs2_cluster_connect(const char *stack_name,
const char *group,
int grouplen,
void (*recovery_handler)(int node_num,
void *recovery_data),
void *recovery_data,
struct ocfs2_cluster_connection **conn);
int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
int hangup_pending);
void ocfs2_cluster_hangup(const char *group, int grouplen);
int ocfs2_cluster_this_node(unsigned int *node);
struct ocfs2_lock_res;
int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
int mode,
union ocfs2_dlm_lksb *lksb,
u32 flags,
void *name,
unsigned int namelen,
struct ocfs2_lock_res *astarg);
int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
union ocfs2_dlm_lksb *lksb,
u32 flags,
struct ocfs2_lock_res *astarg);
int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb);
void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb);
void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb);
void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto);
/* Used by stack plugins */
int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin);
void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin);
#endif /* STACKGLUE_H */
