[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.
 */
struct ocfs2_cluster_connection;
struct ocfs2_dlm_lksb {
	 union {
		 struct dlm_lockstatus lksb_o2dlm;
		 struct dlm_lksb lksb_fsdlm;
		 struct fsdlm_lksb_plus_lvb padding;
	 };
	 struct ocfs2_cluster_connection *lksb_conn;
};

/*
 * 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)(struct ocfs2_dlm_lksb *lksb);
	void (*lp_blocking_ast)(struct ocfs2_dlm_lksb *lksb, int level);
	void (*lp_unlock_ast)(struct 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,
			struct 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,
			  struct 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)(struct ocfs2_dlm_lksb *lksb);

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

	/*
	 * Pull the lvb pointer off of the stack-specific lksb.
	 */
	void *(*lock_lvb)(struct 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)(struct 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,
		   struct ocfs2_dlm_lksb *lksb,
		   u32 flags,
		   void *name,
		   unsigned int namelen);
int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
		     struct ocfs2_dlm_lksb *lksb,
		     u32 flags);

int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb);
int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb);
void *ocfs2_dlm_lvb(struct ocfs2_dlm_lksb *lksb);
void ocfs2_dlm_dump_lksb(struct 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	*/
c0e41338 JB	73	struct ocfs2_cluster_connection;
	74	struct ocfs2_dlm_lksb {
	75	union {
	76	struct dlm_lockstatus lksb_o2dlm;
	77	struct dlm_lksb lksb_fsdlm;
	78	struct fsdlm_lksb_plus_lvb padding;
	79	};
	80	struct ocfs2_cluster_connection *lksb_conn;
8f2c9c1b JB	81	};
8f2c9c1b JB	82
a796d286 JB	83	/*
	84	* The ocfs2_locking_protocol defines the handlers called on ocfs2's behalf.
	85	*/
	86	struct ocfs2_locking_protocol {
	87	struct ocfs2_protocol_version lp_max_version;
c0e41338 JB	88	void (lp_lock_ast)(struct ocfs2_dlm_lksb lksb);
	89	void (lp_blocking_ast)(struct ocfs2_dlm_lksb lksb, int level);
	90	void (lp_unlock_ast)(struct ocfs2_dlm_lksb lksb, int error);
a796d286 JB	91	};
	92
	93
e3dad42b JB	94	/*
	95	* A cluster connection. Mostly opaque to ocfs2, the connection holds
	96	* state for the underlying stack. ocfs2 does use cc_version to determine
	97	* locking compatibility.
	98	*/
4670c46d JB	99	struct ocfs2_cluster_connection {
	100	char cc_name[GROUP_NAME_MAX];
	101	int cc_namelen;
	102	struct ocfs2_protocol_version cc_version;
	103	void (cc_recovery_handler)(int node_num, void recovery_data);
	104	void *cc_recovery_data;
	105	void *cc_lockspace;
	106	void *cc_private;
	107	};
	108
e3dad42b JB	109	/*
	110	* Each cluster stack implements the stack operations structure. Not used
	111	* in the ocfs2 code, the stackglue code translates generic cluster calls
	112	* into stack operations.
	113	*/
	114	struct ocfs2_stack_operations {
	115	/*
	116	* The fs code calls ocfs2_cluster_connect() to attach a new
	117	* filesystem to the cluster stack. The ->connect() op is passed
	118	* an ocfs2_cluster_connection with the name and recovery field
	119	* filled in.
	120	*
	121	* The stack must set up any notification mechanisms and create
	122	* the filesystem lockspace in the DLM. The lockspace should be
	123	* stored on cc_lockspace. Any other information can be stored on
	124	* cc_private.
	125	*
	126	* ->connect() must not return until it is guaranteed that
	127	*
	128	* - Node down notifications for the filesystem will be recieved
	129	* and passed to conn->cc_recovery_handler().
	130	* - Locking requests for the filesystem will be processed.
	131	*/
	132	int (connect)(struct ocfs2_cluster_connection conn);
	133
	134	/*
	135	* The fs code calls ocfs2_cluster_disconnect() when a filesystem
	136	* no longer needs cluster services. All DLM locks have been
	137	* dropped, and recovery notification is being ignored by the
	138	* fs code. The stack must disengage from the DLM and discontinue
	139	* recovery notification.
	140	*
	141	* Once ->disconnect() has returned, the connection structure will
	142	* be freed. Thus, a stack must not return from ->disconnect()
	143	* until it will no longer reference the conn pointer.
286eaa95	144	*
2c39450b JB	145	* Once this call returns, the stack glue will be dropping this
2c39450b JB	146	* connection's reference on the module.
e3dad42b	147	*/
2c39450b	148	int (disconnect)(struct ocfs2_cluster_connection conn);
e3dad42b JB	149
	150	/*
	151	* ->this_node() returns the cluster's unique identifier for the
	152	* local node.
	153	*/
	154	int (this_node)(unsigned int node);
	155
	156	/*
	157	* Call the underlying dlm lock function. The ->dlm_lock()
	158	* callback should convert the flags and mode as appropriate.
	159	*
	160	* ast and bast functions are not part of the call because the
	161	* stack will likely want to wrap ast and bast calls before passing
a796d286 JB	162	* them to stack->sp_proto. There is no astarg. The lksb will
	163	* be passed back to the ast and bast functions. The caller can
	164	* use this to find their object.
e3dad42b JB	165	*/
	166	int (dlm_lock)(struct ocfs2_cluster_connection conn,
	167	int mode,
c0e41338	168	struct ocfs2_dlm_lksb *lksb,
e3dad42b JB	169	u32 flags,
e3dad42b JB	170	void *name,
a796d286	171	unsigned int namelen);
e3dad42b JB	172
	173	/*
	174	* Call the underlying dlm unlock function. The ->dlm_unlock()
	175	* function should convert the flags as appropriate.
	176	*
	177	* The unlock ast is not passed, as the stack will want to wrap
a796d286 JB	178	* it before calling stack->sp_proto->lp_unlock_ast(). There is
	179	* no astarg. The lksb will be passed back to the unlock ast
	180	* function. The caller can use this to find their object.
e3dad42b JB	181	*/
e3dad42b JB	182	int (dlm_unlock)(struct ocfs2_cluster_connection conn,
c0e41338	183	struct ocfs2_dlm_lksb *lksb,
a796d286	184	u32 flags);
e3dad42b JB	185
	186	/*
	187	* Return the status of the current lock status block. The fs
	188	* code should never dereference the union. The ->lock_status()
	189	* callback pulls out the stack-specific lksb, converts the status
	190	* to a proper errno, and returns it.
	191	*/
c0e41338	192	int (lock_status)(struct ocfs2_dlm_lksb lksb);
e3dad42b	193
1c520dfb JB	194	/*
	195	* Return non-zero if the LVB is valid.
	196	*/
c0e41338	197	int (lvb_valid)(struct ocfs2_dlm_lksb lksb);
1c520dfb	198
e3dad42b JB	199	/*
	200	* Pull the lvb pointer off of the stack-specific lksb.
	201	*/
c0e41338	202	void (lock_lvb)(struct ocfs2_dlm_lksb *lksb);
e3dad42b	203
53da4939 MF	204	/*
	205	* Cluster-aware posix locks
	206	*
	207	* This is NULL for stacks which do not support posix locks.
	208	*/
	209	int (plock)(struct ocfs2_cluster_connection conn,
	210	u64 ino,
	211	struct file *file,
	212	int cmd,
	213	struct file_lock *fl);
	214
e3dad42b JB	215	/*
	216	* This is an optoinal debugging hook. If provided, the
	217	* stack can dump debugging information about this lock.
	218	*/
c0e41338	219	void (dump_lksb)(struct ocfs2_dlm_lksb lksb);
e3dad42b JB	220	};
e3dad42b JB	221
286eaa95 JB	222	/*
	223	* Each stack plugin must describe itself by registering a
	224	* ocfs2_stack_plugin structure. This is only seen by stackglue and the
	225	* stack driver.
	226	*/
	227	struct ocfs2_stack_plugin {
	228	char *sp_name;
	229	struct ocfs2_stack_operations *sp_ops;
	230	struct module *sp_owner;
	231
	232	/* These are managed by the stackglue code. */
	233	struct list_head sp_list;
	234	unsigned int sp_count;
	235	struct ocfs2_locking_protocol *sp_proto;
	236	};
	237
	238
	239	/* Used by the filesystem */
9c6c877c JB	240	int ocfs2_cluster_connect(const char *stack_name,
9c6c877c JB	241	const char *group,
4670c46d JB	242	int grouplen,
	243	void (*recovery_handler)(int node_num,
	244	void *recovery_data),
	245	void *recovery_data,
	246	struct ocfs2_cluster_connection **conn);
286eaa95 JB	247	int ocfs2_cluster_disconnect(struct ocfs2_cluster_connection *conn,
286eaa95 JB	248	int hangup_pending);
6953b4c0	249	void ocfs2_cluster_hangup(const char *group, int grouplen);
19fdb624	250	int ocfs2_cluster_this_node(unsigned int *node);
4670c46d	251
cf4d8d75	252	struct ocfs2_lock_res;
4670c46d	253	int ocfs2_dlm_lock(struct ocfs2_cluster_connection *conn,
24ef1815	254	int mode,
c0e41338	255	struct ocfs2_dlm_lksb *lksb,
24ef1815 JB	256	u32 flags,
24ef1815 JB	257	void *name,
a796d286	258	unsigned int namelen);
4670c46d	259	int ocfs2_dlm_unlock(struct ocfs2_cluster_connection *conn,
c0e41338	260	struct ocfs2_dlm_lksb *lksb,
a796d286	261	u32 flags);
24ef1815	262
c0e41338 JB	263	int ocfs2_dlm_lock_status(struct ocfs2_dlm_lksb *lksb);
	264	int ocfs2_dlm_lvb_valid(struct ocfs2_dlm_lksb *lksb);
	265	void ocfs2_dlm_lvb(struct ocfs2_dlm_lksb lksb);
	266	void ocfs2_dlm_dump_lksb(struct ocfs2_dlm_lksb *lksb);
8f2c9c1b	267
53da4939 MF	268	int ocfs2_stack_supports_plocks(void);
	269	int ocfs2_plock(struct ocfs2_cluster_connection *conn, u64 ino,
	270	struct file file, int cmd, struct file_lock fl);
	271
63e0c48a	272	void ocfs2_stack_glue_set_locking_protocol(struct ocfs2_locking_protocol *proto);
24ef1815	273
286eaa95 JB	274
	275	/* Used by stack plugins */
	276	int ocfs2_stack_glue_register(struct ocfs2_stack_plugin *plugin);
	277	void ocfs2_stack_glue_unregister(struct ocfs2_stack_plugin *plugin);
3878f110	278
24ef1815	279	#endif /* STACKGLUE_H */