/*
   * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.

   * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.

   *
   * This copyrighted material is made available to anyone wishing to use,
   * modify, copy, or redistribute it subject to the terms and conditions

   * of the GNU General Public License version 2.

   */
  
  #ifndef __LM_INTERFACE_DOT_H__
  #define __LM_INTERFACE_DOT_H__

  typedef void (*lm_callback_t) (void *ptr, unsigned int type, void *data);

  
  /*
   * lm_mount() flags
   *
   * LM_MFLAG_SPECTATOR
   * GFS is asking to join the filesystem's lockspace, but it doesn't want to
   * modify the filesystem.  The lock module shouldn't assign a journal to the FS
   * mount.  It shouldn't send recovery callbacks to the FS mount.  If the node
   * dies or withdraws, all locks can be wiped immediately.
   */
  
  #define LM_MFLAG_SPECTATOR	0x00000001
  
  /*
   * lm_lockstruct flags
   *
   * LM_LSFLAG_LOCAL
   * The lock_nolock module returns LM_LSFLAG_LOCAL to GFS, indicating that GFS
   * can make single-node optimizations.
   */
  
  #define LM_LSFLAG_LOCAL		0x00000001
  
  /*
   * lm_lockname types
   */
  
  #define LM_TYPE_RESERVED	0x00
  #define LM_TYPE_NONDISK		0x01
  #define LM_TYPE_INODE		0x02
  #define LM_TYPE_RGRP		0x03
  #define LM_TYPE_META		0x04
  #define LM_TYPE_IOPEN		0x05
  #define LM_TYPE_FLOCK		0x06
  #define LM_TYPE_PLOCK		0x07
  #define LM_TYPE_QUOTA		0x08
  #define LM_TYPE_JOURNAL		0x09
  
  /*
   * lm_lock() states
   *
   * SHARED is compatible with SHARED, not with DEFERRED or EX.
   * DEFERRED is compatible with DEFERRED, not with SHARED or EX.
   */
  
  #define LM_ST_UNLOCKED		0
  #define LM_ST_EXCLUSIVE		1
  #define LM_ST_DEFERRED		2
  #define LM_ST_SHARED		3
  
  /*
   * lm_lock() flags
   *
   * LM_FLAG_TRY
   * Don't wait to acquire the lock if it can't be granted immediately.
   *
   * LM_FLAG_TRY_1CB
   * Send one blocking callback if TRY is set and the lock is not granted.
   *
   * LM_FLAG_NOEXP
   * GFS sets this flag on lock requests it makes while doing journal recovery.
   * These special requests should not be blocked due to the recovery like
   * ordinary locks would be.
   *
   * LM_FLAG_ANY
   * A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
   * also be granted in SHARED.  The preferred state is whichever is compatible
   * with other granted locks, or the specified state if no other locks exist.
   *
   * LM_FLAG_PRIORITY
   * Override fairness considerations.  Suppose a lock is held in a shared state
   * and there is a pending request for the deferred state.  A shared lock
   * request with the priority flag would be allowed to bypass the deferred
   * request and directly join the other shared lock.  A shared lock request
   * without the priority flag might be forced to wait until the deferred
   * requested had acquired and released the lock.
   */
  
  #define LM_FLAG_TRY		0x00000001
  #define LM_FLAG_TRY_1CB		0x00000002
  #define LM_FLAG_NOEXP		0x00000004
  #define LM_FLAG_ANY		0x00000008
  #define LM_FLAG_PRIORITY	0x00000010
  
  /*
   * lm_lock() and lm_async_cb return flags
   *
   * LM_OUT_ST_MASK
   * Masks the lower two bits of lock state in the returned value.
   *
   * LM_OUT_CACHEABLE
   * The lock hasn't been released so GFS can continue to cache data for it.
   *
   * LM_OUT_CANCELED
   * The lock request was canceled.
   *
   * LM_OUT_ASYNC
   * The result of the request will be returned in an LM_CB_ASYNC callback.
   */
  
  #define LM_OUT_ST_MASK		0x00000003
  #define LM_OUT_CACHEABLE	0x00000004
  #define LM_OUT_CANCELED		0x00000008
  #define LM_OUT_ASYNC		0x00000080
  #define LM_OUT_ERROR		0x00000100
  
  /*
   * lm_callback_t types
   *
   * LM_CB_NEED_E LM_CB_NEED_D LM_CB_NEED_S
   * Blocking callback, a remote node is requesting the given lock in
   * EXCLUSIVE, DEFERRED, or SHARED.
   *
   * LM_CB_NEED_RECOVERY
   * The given journal needs to be recovered.
   *
   * LM_CB_DROPLOCKS
   * Reduce the number of cached locks.
   *
   * LM_CB_ASYNC
   * The given lock has been granted.
   */
  
  #define LM_CB_NEED_E		257
  #define LM_CB_NEED_D		258
  #define LM_CB_NEED_S		259
  #define LM_CB_NEED_RECOVERY	260
  #define LM_CB_DROPLOCKS		261
  #define LM_CB_ASYNC		262
  
  /*
   * lm_recovery_done() messages
   */
  
  #define LM_RD_GAVEUP		308
  #define LM_RD_SUCCESS		309
  
  
  struct lm_lockname {

  	u64 ln_number;

  	unsigned int ln_type;
  };
  
  #define lm_name_equal(name1, name2) \
  	(((name1)->ln_number == (name2)->ln_number) && \
  	 ((name1)->ln_type == (name2)->ln_type)) \
  
  struct lm_async_cb {
  	struct lm_lockname lc_name;
  	int lc_ret;
  };
  
  struct lm_lockstruct;
  
  struct lm_lockops {

  	const char *lm_proto_name;

  
  	/*
  	 * Mount/Unmount
  	 */
  
  	int (*lm_mount) (char *table_name, char *host_data,

  			 lm_callback_t cb, void *cb_data,

  			 unsigned int min_lvb_size, int flags,
  			 struct lm_lockstruct *lockstruct,
  			 struct kobject *fskobj);

  	void (*lm_others_may_mount) (void *lockspace);

  	void (*lm_unmount) (void *lockspace);

  	void (*lm_withdraw) (void *lockspace);

  
  	/*
  	 * Lock oriented operations
  	 */

  	int (*lm_get_lock) (void *lockspace, struct lm_lockname *name, void **lockp);

  	void (*lm_put_lock) (void *lock);

  	unsigned int (*lm_lock) (void *lock, unsigned int cur_state,

  				 unsigned int req_state, unsigned int flags);

  	unsigned int (*lm_unlock) (void *lock, unsigned int cur_state);

  	void (*lm_cancel) (void *lock);

  	int (*lm_hold_lvb) (void *lock, char **lvbp);
  	void (*lm_unhold_lvb) (void *lock, char *lvb);

  
  	/*
  	 * Posix Lock oriented operations
  	 */

  	int (*lm_plock_get) (void *lockspace, struct lm_lockname *name,

  			     struct file *file, struct file_lock *fl);

  	int (*lm_plock) (void *lockspace, struct lm_lockname *name,

  			 struct file *file, int cmd, struct file_lock *fl);

  	int (*lm_punlock) (void *lockspace, struct lm_lockname *name,

  			   struct file *file, struct file_lock *fl);
  
  	/*
  	 * Client oriented operations
  	 */

  	void (*lm_recovery_done) (void *lockspace, unsigned int jid,

  				  unsigned int message);
  
  	struct module *lm_owner;
  };
  
  /*
   * lm_mount() return values
   *
   * ls_jid - the journal ID this node should use
   * ls_first - this node is the first to mount the file system
   * ls_lvb_size - size in bytes of lock value blocks
   * ls_lockspace - lock module's context for this file system
   * ls_ops - lock module's functions
   * ls_flags - lock module features
   */
  
  struct lm_lockstruct {
  	unsigned int ls_jid;
  	unsigned int ls_first;
  	unsigned int ls_lvb_size;

  	void *ls_lockspace;
  	const struct lm_lockops *ls_ops;

  	int ls_flags;
  };

  /*
   * Lock module bottom interface.  A lock module makes itself available to GFS
   * with these functions.

   */

  int gfs2_register_lockproto(const struct lm_lockops *proto);
  void gfs2_unregister_lockproto(const struct lm_lockops *proto);

  
  /*
   * Lock module top interface.  GFS calls these functions when mounting or
   * unmounting a file system.
   */
  
  int gfs2_mount_lockproto(char *proto_name, char *table_name, char *host_data,

  			 lm_callback_t cb, void *cb_data,

  			 unsigned int min_lvb_size, int flags,
  			 struct lm_lockstruct *lockstruct,
  			 struct kobject *fskobj);
  
  void gfs2_unmount_lockproto(struct lm_lockstruct *lockstruct);
  
  void gfs2_withdraw_lockproto(struct lm_lockstruct *lockstruct);
  
  #endif /* __LM_INTERFACE_DOT_H__ */