[linux-2.6-block.git] / fs / ocfs2 / stackglue.h

/* -*- 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>

/* Needed for plock-related prototypes */
struct file;
struct file_lock;

/*
 * 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 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;
};

/*
 * 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)(union ocfs2_dlm_lksb *lksb);
	void (*lp_blocking_ast)(union ocfs2_dlm_lksb *lksb, int level);
	void (*lp_unlock_ast)(union ocfs2_dlm_lksb *lksb, int error);
};


/*
 * 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.  There is no astarg.  The lksb will
	 * be passed back to the ast and bast functions.  The caller can
	 * use this to find their object.
	 */
	int (*dlm_lock)(struct ocfs2_cluster_connection *conn,
			int mode,
			union ocfs2_dlm_lksb *lksb,
			u32 flags,
			void *name,
			unsigned int namelen);

	/*
	 * 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().  There is
	 * no astarg.  The lksb will be passed back to the unlock ast
	 * function.  The caller can use this to find their object.
	 */
	int (*dlm_unlock)(struct ocfs2_cluster_connection *conn,
			  union ocfs2_dlm_lksb *lksb,
			  u32 flags);

	/*
	 * 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);

	/*
	 * Return non-zero if the LVB is valid.
	 */
	int (*lvb_valid)(union ocfs2_dlm_lksb *lksb);

	/*
	 * Pull the lvb pointer off of the stack-specific lksb.
	 */
	void *(*lock_lvb)(union ocfs2_dlm_lksb *lksb);

	/*
	 * Cluster-aware posix locks
	 *
	 * This is NULL for stacks which do not support posix locks.
	 */
	int (*plock)(struct ocfs2_cluster_connection *conn,
		     u64 ino,
		     struct file *file,
		     int cmd,
		     struct file_lock *fl);

	/*
	 * 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);
int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
		     union ocfs2_dlm_lksb *lksb,
		     u32 flags);

int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb);
int ocfs2_dlm_lvb_valid(union ocfs2_dlm_lksb *lksb);
void *ocfs2_dlm_lvb(union ocfs2_dlm_lksb *lksb);
void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb);

int ocfs2_stack_supports_plocks(void);
int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
		struct file *file, int cmd, struct file_lock *fl);

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 */
Commit	Line	Data
24ef1815 JB	1	/* -- mode: c; c-basic-offset: 8; --
	2	* vim: noexpandtab sw=8 ts=8 sts=0:
	3	*
	4	* stackglue.h
	5	*
	6	* Glue to the underlying cluster stack.
	7	*
	8	* Copyright (C) 2007 Oracle. All rights reserved.
	9	*
	10	* This program is free software; you can redistribute it and/or
	11	* modify it under the terms of the GNU General Public
	12	* License as published by the Free Software Foundation, version 2.
	13	*
	14	* This program is distributed in the hope that it will be useful,
	15	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	17	* General Public License for more details.
	18	*/
	19
	20
	21	#ifndef STACKGLUE_H
	22	#define STACKGLUE_H
	23
bd3e7610 JB	24	#include <linux/types.h>
	25	#include <linux/list.h>
	26	#include <linux/dlmconstants.h>
	27
e3dad42b	28	#include "dlm/dlmapi.h"
cf4d8d75	29	#include <linux/dlm.h>
e3dad42b	30
53da4939 MF	31	/* Needed for plock-related prototypes */
	32	struct file;
	33	struct file_lock;
	34
bd3e7610 JB	35	/*
	36	* dlmconstants.h does not have a LOCAL flag. We hope to remove it
	37	* some day, but right now we need it. Let's fake it. This value is larger
	38	* than any flag in dlmconstants.h.
	39	*/
	40	#define DLM_LKF_LOCAL 0x00100000
	41
4670c46d JB	42	/*
	43	* This shadows DLM_LOCKSPACE_LEN in fs/dlm/dlm_internal.h. That probably
	44	* wants to be in a public header.
	45	*/
	46	#define GROUP_NAME_MAX 64
	47
	48
e3dad42b JB	49	/*
	50	* ocfs2_protocol_version changes when ocfs2 does something different in
	51	* its inter-node behavior. See dlmglue.c for more information.
	52	*/
4670c46d JB	53	struct ocfs2_protocol_version {
	54	u8 pv_major;
	55	u8 pv_minor;
	56	};
	57
cf4d8d75 DT	58	/*
	59	* The dlm_lockstatus struct includes lvb space, but the dlm_lksb struct only
	60	* has a pointer to separately allocated lvb space. This struct exists only to
	61	* include in the lksb union to make space for a combined dlm_lksb and lvb.
	62	*/
	63	struct fsdlm_lksb_plus_lvb {
	64	struct dlm_lksb lksb;
	65	char lvb[DLM_LVB_LEN];
	66	};
	67
e3dad42b JB	68	/*
	69	* A union of all lock status structures. We define it here so that the
	70	* size of the union is known. Lock status structures are embedded in
	71	* ocfs2 inodes.
	72	*/
8f2c9c1b JB	73	union ocfs2_dlm_lksb {
8f2c9c1b JB	74	struct dlm_lockstatus lksb_o2dlm;
cf4d8d75 DT	75	struct dlm_lksb lksb_fsdlm;
cf4d8d75 DT	76	struct fsdlm_lksb_plus_lvb padding;
8f2c9c1b JB	77	};
8f2c9c1b JB	78
a796d286 JB	79	/*
	80	* The ocfs2_locking_protocol defines the handlers called on ocfs2's behalf.
	81	*/
	82	struct ocfs2_locking_protocol {
	83	struct ocfs2_protocol_version lp_max_version;
	84	void (lp_lock_ast)(union ocfs2_dlm_lksb lksb);
	85	void (lp_blocking_ast)(union ocfs2_dlm_lksb lksb, int level);
	86	void (lp_unlock_ast)(union ocfs2_dlm_lksb lksb, int error);
	87	};
	88
	89
e3dad42b JB	90	/*
	91	* A cluster connection. Mostly opaque to ocfs2, the connection holds
	92	* state for the underlying stack. ocfs2 does use cc_version to determine
	93	* locking compatibility.
	94	*/
4670c46d JB	95	struct ocfs2_cluster_connection {
	96	char cc_name[GROUP_NAME_MAX];
	97	int cc_namelen;
	98	struct ocfs2_protocol_version cc_version;
	99	void (cc_recovery_handler)(int node_num, void recovery_data);
	100	void *cc_recovery_data;
	101	void *cc_lockspace;
	102	void *cc_private;
	103	};
	104
e3dad42b JB	105	/*
	106	* Each cluster stack implements the stack operations structure. Not used
	107	* in the ocfs2 code, the stackglue code translates generic cluster calls
	108	* into stack operations.
	109	*/
	110	struct ocfs2_stack_operations {
	111	/*
	112	* The fs code calls ocfs2_cluster_connect() to attach a new
	113	* filesystem to the cluster stack. The ->connect() op is passed
	114	* an ocfs2_cluster_connection with the name and recovery field
	115	* filled in.
	116	*
	117	* The stack must set up any notification mechanisms and create
	118	* the filesystem lockspace in the DLM. The lockspace should be
	119	* stored on cc_lockspace. Any other information can be stored on
	120	* cc_private.
	121	*
	122	* ->connect() must not return until it is guaranteed that
	123	*
	124	* - Node down notifications for the filesystem will be recieved
	125	* and passed to conn->cc_recovery_handler().
	126	* - Locking requests for the filesystem will be processed.
	127	*/
	128	int (connect)(struct ocfs2_cluster_connection conn);
	129
	130	/*
	131	* The fs code calls ocfs2_cluster_disconnect() when a filesystem
	132	* no longer needs cluster services. All DLM locks have been
	133	* dropped, and recovery notification is being ignored by the
	134	* fs code. The stack must disengage from the DLM and discontinue
	135	* recovery notification.
	136	*
	137	* Once ->disconnect() has returned, the connection structure will
	138	* be freed. Thus, a stack must not return from ->disconnect()
	139	* until it will no longer reference the conn pointer.
286eaa95	140	*
2c39450b JB	141	* Once this call returns, the stack glue will be dropping this
2c39450b JB	142	* connection's reference on the module.
e3dad42b	143	*/
2c39450b	144	int (disconnect)(struct ocfs2_cluster_connection conn);
e3dad42b JB	145
	146	/*
	147	* ->this_node() returns the cluster's unique identifier for the
	148	* local node.
	149	*/
	150	int (this_node)(unsigned int node);
	151
	152	/*
	153	* Call the underlying dlm lock function. The ->dlm_lock()
	154	* callback should convert the flags and mode as appropriate.
	155	*
	156	* ast and bast functions are not part of the call because the
	157	* stack will likely want to wrap ast and bast calls before passing
a796d286 JB	158	* them to stack->sp_proto. There is no astarg. The lksb will
	159	* be passed back to the ast and bast functions. The caller can
	160	* use this to find their object.
e3dad42b JB	161	*/
	162	int (dlm_lock)(struct ocfs2_cluster_connection conn,
	163	int mode,
	164	union ocfs2_dlm_lksb *lksb,
	165	u32 flags,
	166	void *name,
a796d286	167	unsigned int namelen);
e3dad42b JB	168
	169	/*
	170	* Call the underlying dlm unlock function. The ->dlm_unlock()
	171	* function should convert the flags as appropriate.
	172	*
	173	* The unlock ast is not passed, as the stack will want to wrap
a796d286 JB	174	* it before calling stack->sp_proto->lp_unlock_ast(). There is
	175	* no astarg. The lksb will be passed back to the unlock ast
	176	* function. The caller can use this to find their object.
e3dad42b JB	177	*/
	178	int (dlm_unlock)(struct ocfs2_cluster_connection conn,
	179	union ocfs2_dlm_lksb *lksb,
a796d286	180	u32 flags);
e3dad42b JB	181
	182	/*
	183	* Return the status of the current lock status block. The fs
	184	* code should never dereference the union. The ->lock_status()
	185	* callback pulls out the stack-specific lksb, converts the status
	186	* to a proper errno, and returns it.
	187	*/
	188	int (lock_status)(union ocfs2_dlm_lksb lksb);
	189
1c520dfb JB	190	/*
	191	* Return non-zero if the LVB is valid.
	192	*/
	193	int (lvb_valid)(union ocfs2_dlm_lksb lksb);
	194
e3dad42b JB	195	/*
	196	* Pull the lvb pointer off of the stack-specific lksb.
	197	*/
	198	void (lock_lvb)(union ocfs2_dlm_lksb *lksb);
	199
53da4939 MF	200	/*
	201	* Cluster-aware posix locks
	202	*
	203	* This is NULL for stacks which do not support posix locks.
	204	*/
	205	int (plock)(struct ocfs2_cluster_connection conn,
	206	u64 ino,
	207	struct file *file,
	208	int cmd,
	209	struct file_lock *fl);
	210
e3dad42b JB	211	/*
	212	* This is an optoinal debugging hook. If provided, the
	213	* stack can dump debugging information about this lock.
	214	*/
	215	void (dump_lksb)(union ocfs2_dlm_lksb lksb);
	216	};
	217
286eaa95 JB	218	/*
	219	* Each stack plugin must describe itself by registering a
	220	* ocfs2_stack_plugin structure. This is only seen by stackglue and the
	221	* stack driver.
	222	*/
	223	struct ocfs2_stack_plugin {
	224	char *sp_name;
	225	struct ocfs2_stack_operations *sp_ops;
	226	struct module *sp_owner;
	227
	228	/* These are managed by the stackglue code. */
	229	struct list_head sp_list;
	230	unsigned int sp_count;
	231	struct ocfs2_locking_protocol *sp_proto;
	232	};
	233
	234
	235	/* Used by the filesystem */
9c6c877c JB	236	int ocfs2_cluster_connect(const char *stack_name,
9c6c877c JB	237	const char *group,
4670c46d JB	238	int grouplen,
	239	void (*recovery_handler)(int node_num,
	240	void *recovery_data),
	241	void *recovery_data,
	242	struct ocfs2_cluster_connection **conn);
286eaa95 JB	243	int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
286eaa95 JB	244	int hangup_pending);
6953b4c0	245	void ocfs2_cluster_hangup(const char *group, int grouplen);
19fdb624	246	int ocfs2_cluster_this_node(unsigned int *node);
4670c46d	247
cf4d8d75	248	struct ocfs2_lock_res;
4670c46d	249	int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
24ef1815	250	int mode,
8f2c9c1b	251	union ocfs2_dlm_lksb *lksb,
24ef1815 JB	252	u32 flags,
24ef1815 JB	253	void *name,
a796d286	254	unsigned int namelen);
4670c46d	255	int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
8f2c9c1b	256	union ocfs2_dlm_lksb *lksb,
a796d286	257	u32 flags);
24ef1815	258
8f2c9c1b	259	int ocfs2_dlm_lock_status(union ocfs2_dlm_lksb *lksb);
1c520dfb	260	int ocfs2_dlm_lvb_valid(union ocfs2_dlm_lksb *lksb);
8f2c9c1b	261	void ocfs2_dlm_lvb(union ocfs2_dlm_lksb lksb);
cf0acdcd	262	void ocfs2_dlm_dump_lksb(union ocfs2_dlm_lksb *lksb);
8f2c9c1b	263
53da4939 MF	264	int ocfs2_stack_supports_plocks(void);
	265	int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
	266	struct file file, int cmd, struct file_lock fl);
	267
63e0c48a	268	void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto);
24ef1815	269
286eaa95 JB	270
	271	/* Used by stack plugins */
	272	int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin);
	273	void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin);
3878f110	274
24ef1815	275	#endif /* STACKGLUE_H */