linux/fs/gfs2/glock.h

/*
 * 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 __GLOCK_DOT_H__
#define __GLOCK_DOT_H__

#include <linux/sched.h>
#include "incore.h"

/* Flags for lock requests; used in gfs2_holder gh_flag field.
   From lm_interface.h:
#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 */

#define GL_ASYNC		0x00000040
#define GL_EXACT		0x00000080
#define GL_SKIP			0x00000100
#define GL_ATIME		0x00000200
#define GL_NOCACHE		0x00000400
#define GL_FLOCK		0x00000800
#define GL_NOCANCEL		0x00001000

#define GLR_TRYFAILED		13
#define GLR_CANCELED		14

static inline int gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
{
	struct gfs2_holder *gh;
	int locked = 0;
	struct pid *pid;

	/* Look in glock's list of holders for one with current task as owner */
	spin_lock(&gl->gl_spin);
	pid = task_pid(current);
	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
		if (gh->gh_owner_pid == pid) {
			locked = 1;
			break;
		}
	}
	spin_unlock(&gl->gl_spin);

	return locked;
}

static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
{
	return gl->gl_state == LM_ST_EXCLUSIVE;
}

static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
{
	return gl->gl_state == LM_ST_DEFERRED;
}

static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
{
	return gl->gl_state == LM_ST_SHARED;
}

static inline int gfs2_glock_is_blocking(struct gfs2_glock *gl)
{
	int ret;
	spin_lock(&gl->gl_spin);
	ret = test_bit(GLF_DEMOTE, &gl->gl_flags) || !list_empty(&gl->gl_waiters3);
	spin_unlock(&gl->gl_spin);
	return ret;
}

int gfs2_glock_get(struct gfs2_sbd *sdp,
		   u64 number, const struct gfs2_glock_operations *glops,
		   int create, struct gfs2_glock **glp);
int gfs2_glock_put(struct gfs2_glock *gl);
void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
		      struct gfs2_holder *gh);
void gfs2_holder_reinit(unsigned int state, unsigned flags,
			struct gfs2_holder *gh);
void gfs2_holder_uninit(struct gfs2_holder *gh);
int gfs2_glock_nq(struct gfs2_holder *gh);
int gfs2_glock_poll(struct gfs2_holder *gh);
int gfs2_glock_wait(struct gfs2_holder *gh);
void gfs2_glock_dq(struct gfs2_holder *gh);
void gfs2_glock_dq_wait(struct gfs2_holder *gh);

void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
int gfs2_glock_nq_num(struct gfs2_sbd *sdp,
		      u64 number, const struct gfs2_glock_operations *glops,
		      unsigned int state, int flags, struct gfs2_holder *gh);

int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs);

/**
 * gfs2_glock_nq_init - intialize a holder and enqueue it on a glock
 * @gl: the glock
 * @state: the state we're requesting
 * @flags: the modifier flags
 * @gh: the holder structure
 *
 * Returns: 0, GLR_*, or errno
 */

static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
				     unsigned int state, int flags,
				     struct gfs2_holder *gh)
{
	int error;

	gfs2_holder_init(gl, state, flags, gh);

	error = gfs2_glock_nq(gh);
	if (error)
		gfs2_holder_uninit(gh);

	return error;
}

/*  Lock Value Block functions  */

int gfs2_lvb_hold(struct gfs2_glock *gl);
void gfs2_lvb_unhold(struct gfs2_glock *gl);

void gfs2_glock_cb(void *cb_data, unsigned int type, void *data);

void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl);
void gfs2_reclaim_glock(struct gfs2_sbd *sdp);
void gfs2_gl_hash_clear(struct gfs2_sbd *sdp, int wait);

int __init gfs2_glock_init(void);
void gfs2_glock_exit(void);

int gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
int gfs2_register_debugfs(void);
void gfs2_unregister_debugfs(void);

#endif /* __GLOCK_DOT_H__ */