linux/fs/gfs2/glock.h
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   1/*
   2 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3 * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
   4 *
   5 * This copyrighted material is made available to anyone wishing to use,
   6 * modify, copy, or redistribute it subject to the terms and conditions
   7 * of the GNU General Public License version 2.
   8 */
   9
  10#ifndef __GLOCK_DOT_H__
  11#define __GLOCK_DOT_H__
  12
  13#include <linux/sched.h>
  14#include <linux/parser.h>
  15#include "incore.h"
  16
  17/* Options for hostdata parser */
  18
  19enum {
  20        Opt_jid,
  21        Opt_id,
  22        Opt_first,
  23        Opt_nodir,
  24        Opt_err,
  25};
  26
  27/*
  28 * lm_lockname types
  29 */
  30
  31#define LM_TYPE_RESERVED        0x00
  32#define LM_TYPE_NONDISK         0x01
  33#define LM_TYPE_INODE           0x02
  34#define LM_TYPE_RGRP            0x03
  35#define LM_TYPE_META            0x04
  36#define LM_TYPE_IOPEN           0x05
  37#define LM_TYPE_FLOCK           0x06
  38#define LM_TYPE_PLOCK           0x07
  39#define LM_TYPE_QUOTA           0x08
  40#define LM_TYPE_JOURNAL         0x09
  41
  42/*
  43 * lm_lock() states
  44 *
  45 * SHARED is compatible with SHARED, not with DEFERRED or EX.
  46 * DEFERRED is compatible with DEFERRED, not with SHARED or EX.
  47 */
  48
  49#define LM_ST_UNLOCKED          0
  50#define LM_ST_EXCLUSIVE         1
  51#define LM_ST_DEFERRED          2
  52#define LM_ST_SHARED            3
  53
  54/*
  55 * lm_lock() flags
  56 *
  57 * LM_FLAG_TRY
  58 * Don't wait to acquire the lock if it can't be granted immediately.
  59 *
  60 * LM_FLAG_TRY_1CB
  61 * Send one blocking callback if TRY is set and the lock is not granted.
  62 *
  63 * LM_FLAG_NOEXP
  64 * GFS sets this flag on lock requests it makes while doing journal recovery.
  65 * These special requests should not be blocked due to the recovery like
  66 * ordinary locks would be.
  67 *
  68 * LM_FLAG_ANY
  69 * A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
  70 * also be granted in SHARED.  The preferred state is whichever is compatible
  71 * with other granted locks, or the specified state if no other locks exist.
  72 *
  73 * LM_FLAG_PRIORITY
  74 * Override fairness considerations.  Suppose a lock is held in a shared state
  75 * and there is a pending request for the deferred state.  A shared lock
  76 * request with the priority flag would be allowed to bypass the deferred
  77 * request and directly join the other shared lock.  A shared lock request
  78 * without the priority flag might be forced to wait until the deferred
  79 * requested had acquired and released the lock.
  80 */
  81
  82#define LM_FLAG_TRY             0x00000001
  83#define LM_FLAG_TRY_1CB         0x00000002
  84#define LM_FLAG_NOEXP           0x00000004
  85#define LM_FLAG_ANY             0x00000008
  86#define LM_FLAG_PRIORITY        0x00000010
  87#define GL_ASYNC                0x00000040
  88#define GL_EXACT                0x00000080
  89#define GL_SKIP                 0x00000100
  90#define GL_NOCACHE              0x00000400
  91  
  92/*
  93 * lm_async_cb return flags
  94 *
  95 * LM_OUT_ST_MASK
  96 * Masks the lower two bits of lock state in the returned value.
  97 *
  98 * LM_OUT_CANCELED
  99 * The lock request was canceled.
 100 *
 101 */
 102
 103#define LM_OUT_ST_MASK          0x00000003
 104#define LM_OUT_CANCELED         0x00000008
 105#define LM_OUT_ERROR            0x00000004
 106
 107/*
 108 * lm_recovery_done() messages
 109 */
 110
 111#define LM_RD_GAVEUP            308
 112#define LM_RD_SUCCESS           309
 113
 114#define GLR_TRYFAILED           13
 115
 116#define GL_GLOCK_MAX_HOLD        (long)(HZ / 5)
 117#define GL_GLOCK_DFT_HOLD        (long)(HZ / 5)
 118#define GL_GLOCK_MIN_HOLD        (long)(10)
 119#define GL_GLOCK_HOLD_INCR       (long)(HZ / 20)
 120#define GL_GLOCK_HOLD_DECR       (long)(HZ / 40)
 121
 122struct lm_lockops {
 123        const char *lm_proto_name;
 124        int (*lm_mount) (struct gfs2_sbd *sdp, const char *table);
 125        void (*lm_first_done) (struct gfs2_sbd *sdp);
 126        void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid,
 127                                    unsigned int result);
 128        void (*lm_unmount) (struct gfs2_sbd *sdp);
 129        void (*lm_withdraw) (struct gfs2_sbd *sdp);
 130        void (*lm_put_lock) (struct gfs2_glock *gl);
 131        int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,
 132                        unsigned int flags);
 133        void (*lm_cancel) (struct gfs2_glock *gl);
 134        const match_table_t *lm_tokens;
 135};
 136
 137extern struct workqueue_struct *gfs2_delete_workqueue;
 138static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
 139{
 140        struct gfs2_holder *gh;
 141        struct pid *pid;
 142
 143        /* Look in glock's list of holders for one with current task as owner */
 144        spin_lock(&gl->gl_spin);
 145        pid = task_pid(current);
 146        list_for_each_entry(gh, &gl->gl_holders, gh_list) {
 147                if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
 148                        break;
 149                if (gh->gh_owner_pid == pid)
 150                        goto out;
 151        }
 152        gh = NULL;
 153out:
 154        spin_unlock(&gl->gl_spin);
 155
 156        return gh;
 157}
 158
 159static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
 160{
 161        return gl->gl_state == LM_ST_EXCLUSIVE;
 162}
 163
 164static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
 165{
 166        return gl->gl_state == LM_ST_DEFERRED;
 167}
 168
 169static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
 170{
 171        return gl->gl_state == LM_ST_SHARED;
 172}
 173
 174static inline struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl)
 175{
 176        if (gl->gl_ops->go_flags & GLOF_ASPACE)
 177                return (struct address_space *)(gl + 1);
 178        return NULL;
 179}
 180
 181int gfs2_glock_get(struct gfs2_sbd *sdp,
 182                   u64 number, const struct gfs2_glock_operations *glops,
 183                   int create, struct gfs2_glock **glp);
 184void gfs2_glock_hold(struct gfs2_glock *gl);
 185void gfs2_glock_put_nolock(struct gfs2_glock *gl);
 186void gfs2_glock_put(struct gfs2_glock *gl);
 187void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
 188                      struct gfs2_holder *gh);
 189void gfs2_holder_reinit(unsigned int state, unsigned flags,
 190                        struct gfs2_holder *gh);
 191void gfs2_holder_uninit(struct gfs2_holder *gh);
 192int gfs2_glock_nq(struct gfs2_holder *gh);
 193int gfs2_glock_poll(struct gfs2_holder *gh);
 194int gfs2_glock_wait(struct gfs2_holder *gh);
 195void gfs2_glock_dq(struct gfs2_holder *gh);
 196void gfs2_glock_dq_wait(struct gfs2_holder *gh);
 197
 198void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
 199int gfs2_glock_nq_num(struct gfs2_sbd *sdp,
 200                      u64 number, const struct gfs2_glock_operations *glops,
 201                      unsigned int state, int flags, struct gfs2_holder *gh);
 202
 203int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 204void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 205void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs);
 206
 207__printf(2, 3)
 208void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
 209
 210/**
 211 * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
 212 * @gl: the glock
 213 * @state: the state we're requesting
 214 * @flags: the modifier flags
 215 * @gh: the holder structure
 216 *
 217 * Returns: 0, GLR_*, or errno
 218 */
 219
 220static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
 221                                     unsigned int state, int flags,
 222                                     struct gfs2_holder *gh)
 223{
 224        int error;
 225
 226        gfs2_holder_init(gl, state, flags, gh);
 227
 228        error = gfs2_glock_nq(gh);
 229        if (error)
 230                gfs2_holder_uninit(gh);
 231
 232        return error;
 233}
 234
 235extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
 236extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
 237extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
 238extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
 239extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
 240extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
 241extern void gfs2_glock_free(struct gfs2_glock *gl);
 242
 243extern int __init gfs2_glock_init(void);
 244extern void gfs2_glock_exit(void);
 245
 246extern int gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
 247extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
 248extern int gfs2_register_debugfs(void);
 249extern void gfs2_unregister_debugfs(void);
 250
 251extern const struct lm_lockops gfs2_dlm_ops;
 252
 253#endif /* __GLOCK_DOT_H__ */
 254
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