glock.h

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/*
 * 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 <linux/parser.h>
#include "incore.h"

/* Options for hostdata parser */

enum {
    Opt_jid,
    Opt_id,
    Opt_first,
    Opt_nodir,
    Opt_err,
};

/*
 * 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
#define GL_ASYNC        0x00000040
#define GL_EXACT        0x00000080
#define GL_SKIP         0x00000100
#define GL_NOCACHE      0x00000400
  
/*
 * lm_async_cb return flags
 *
 * LM_OUT_ST_MASK
 * Masks the lower two bits of lock state in the returned value.
 *
 * LM_OUT_CANCELED
 * The lock request was canceled.
 *
 */

#define LM_OUT_ST_MASK      0x00000003
#define LM_OUT_CANCELED     0x00000008
#define LM_OUT_ERROR        0x00000004

/*
 * lm_recovery_done() messages
 */

#define LM_RD_GAVEUP        308
#define LM_RD_SUCCESS       309

#define GLR_TRYFAILED       13

#define GL_GLOCK_MAX_HOLD        (long)(HZ / 5)
#define GL_GLOCK_DFT_HOLD        (long)(HZ / 5)
#define GL_GLOCK_MIN_HOLD        (long)(10)
#define GL_GLOCK_HOLD_INCR       (long)(HZ / 20)
#define GL_GLOCK_HOLD_DECR       (long)(HZ / 40)

struct lm_lockops {
    const char *lm_proto_name;
    int (*lm_mount) (struct gfs2_sbd *sdp, const char *table);
    void (*lm_first_done) (struct gfs2_sbd *sdp);
    void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid,
                    unsigned int result);
    void (*lm_unmount) (struct gfs2_sbd *sdp);
    void (*lm_withdraw) (struct gfs2_sbd *sdp);
    void (*lm_put_lock) (struct gfs2_glock *gl);
    int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,
            unsigned int flags);
    void (*lm_cancel) (struct gfs2_glock *gl);
    const match_table_t *lm_tokens;
};

extern struct workqueue_struct *gfs2_delete_workqueue;
static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
{
    struct gfs2_holder *gh;
    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 (!test_bit(HIF_HOLDER, &gh->gh_iflags))
            break;
        if (gh->gh_owner_pid == pid)
            goto out;
    }
    gh = NULL;
out:
    spin_unlock(&gl->gl_spin);

    return gh;
}

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 struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl)
{
    if (gl->gl_ops->go_flags & GLOF_ASPACE)
        return (struct address_space *)(gl + 1);
    return NULL;
}

int gfs2_glock_get(struct gfs2_sbd *sdp,
           u64 number, const struct gfs2_glock_operations *glops,
           int create, struct gfs2_glock **glp);
void gfs2_glock_hold(struct gfs2_glock *gl);
void gfs2_glock_put_nolock(struct gfs2_glock *gl);
void 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);

__printf(2, 3)
void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);

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;
}

extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
extern void gfs2_glock_free(struct gfs2_glock *gl);

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

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

extern const struct lm_lockops gfs2_dlm_ops;

#endif /* __GLOCK_DOT_H__ */