LXR linux/fs/gfs2/glock.h

   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#include "util.h"
  17
  18/* Options for hostdata parser */
  19
  20enum {
  21        Opt_jid,
  22        Opt_id,
  23        Opt_first,
  24        Opt_nodir,
  25        Opt_err,
  26};
  27
  28/*
  29 * lm_lockname types
  30 */
  31
  32#define LM_TYPE_RESERVED        0x00
  33#define LM_TYPE_NONDISK         0x01
  34#define LM_TYPE_INODE           0x02
  35#define LM_TYPE_RGRP            0x03
  36#define LM_TYPE_META            0x04
  37#define LM_TYPE_IOPEN           0x05
  38#define LM_TYPE_FLOCK           0x06
  39#define LM_TYPE_PLOCK           0x07
  40#define LM_TYPE_QUOTA           0x08
  41#define LM_TYPE_JOURNAL         0x09
  42
  43/*
  44 * lm_lock() states
  45 *
  46 * SHARED is compatible with SHARED, not with DEFERRED or EX.
  47 * DEFERRED is compatible with DEFERRED, not with SHARED or EX.
  48 */
  49
  50#define LM_ST_UNLOCKED          0
  51#define LM_ST_EXCLUSIVE         1
  52#define LM_ST_DEFERRED          2
  53#define LM_ST_SHARED            3
  54
  55/*
  56 * lm_lock() flags
  57 *
  58 * LM_FLAG_TRY
  59 * Don't wait to acquire the lock if it can't be granted immediately.
  60 *
  61 * LM_FLAG_TRY_1CB
  62 * Send one blocking callback if TRY is set and the lock is not granted.
  63 *
  64 * LM_FLAG_NOEXP
  65 * GFS sets this flag on lock requests it makes while doing journal recovery.
  66 * These special requests should not be blocked due to the recovery like
  67 * ordinary locks would be.
  68 *
  69 * LM_FLAG_ANY
  70 * A SHARED request may also be granted in DEFERRED, or a DEFERRED request may
  71 * also be granted in SHARED.  The preferred state is whichever is compatible
  72 * with other granted locks, or the specified state if no other locks exist.
  73 *
  74 * LM_FLAG_PRIORITY
  75 * Override fairness considerations.  Suppose a lock is held in a shared state
  76 * and there is a pending request for the deferred state.  A shared lock
  77 * request with the priority flag would be allowed to bypass the deferred
  78 * request and directly join the other shared lock.  A shared lock request
  79 * without the priority flag might be forced to wait until the deferred
  80 * requested had acquired and released the lock.
  81 */
  82
  83#define LM_FLAG_TRY             0x0001
  84#define LM_FLAG_TRY_1CB         0x0002
  85#define LM_FLAG_NOEXP           0x0004
  86#define LM_FLAG_ANY             0x0008
  87#define LM_FLAG_PRIORITY        0x0010
  88#define GL_ASYNC                0x0040
  89#define GL_EXACT                0x0080
  90#define GL_SKIP                 0x0100
  91#define GL_NOCACHE              0x0400
  92  
  93/*
  94 * lm_async_cb return flags
  95 *
  96 * LM_OUT_ST_MASK
  97 * Masks the lower two bits of lock state in the returned value.
  98 *
  99 * LM_OUT_CANCELED
 100 * The lock request was canceled.
 101 *
 102 */
 103
 104#define LM_OUT_ST_MASK          0x00000003
 105#define LM_OUT_CANCELED         0x00000008
 106#define LM_OUT_ERROR            0x00000004
 107
 108/*
 109 * lm_recovery_done() messages
 110 */
 111
 112#define LM_RD_GAVEUP            308
 113#define LM_RD_SUCCESS           309
 114
 115#define GLR_TRYFAILED           13
 116
 117#define GL_GLOCK_MAX_HOLD        (long)(HZ / 5)
 118#define GL_GLOCK_DFT_HOLD        (long)(HZ / 5)
 119#define GL_GLOCK_MIN_HOLD        (long)(10)
 120#define GL_GLOCK_HOLD_INCR       (long)(HZ / 20)
 121#define GL_GLOCK_HOLD_DECR       (long)(HZ / 40)
 122
 123struct lm_lockops {
 124        const char *lm_proto_name;
 125        int (*lm_mount) (struct gfs2_sbd *sdp, const char *table);
 126        void (*lm_first_done) (struct gfs2_sbd *sdp);
 127        void (*lm_recovery_result) (struct gfs2_sbd *sdp, unsigned int jid,
 128                                    unsigned int result);
 129        void (*lm_unmount) (struct gfs2_sbd *sdp);
 130        void (*lm_withdraw) (struct gfs2_sbd *sdp);
 131        void (*lm_put_lock) (struct gfs2_glock *gl);
 132        int (*lm_lock) (struct gfs2_glock *gl, unsigned int req_state,
 133                        unsigned int flags);
 134        void (*lm_cancel) (struct gfs2_glock *gl);
 135        const match_table_t *lm_tokens;
 136};
 137
 138extern struct workqueue_struct *gfs2_delete_workqueue;
 139static inline struct gfs2_holder *gfs2_glock_is_locked_by_me(struct gfs2_glock *gl)
 140{
 141        struct gfs2_holder *gh;
 142        struct pid *pid;
 143
 144        /* Look in glock's list of holders for one with current task as owner */
 145        spin_lock(&gl->gl_lockref.lock);
 146        pid = task_pid(current);
 147        list_for_each_entry(gh, &gl->gl_holders, gh_list) {
 148                if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
 149                        break;
 150                if (gh->gh_owner_pid == pid)
 151                        goto out;
 152        }
 153        gh = NULL;
 154out:
 155        spin_unlock(&gl->gl_lockref.lock);
 156
 157        return gh;
 158}
 159
 160static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
 161{
 162        return gl->gl_state == LM_ST_EXCLUSIVE;
 163}
 164
 165static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
 166{
 167        return gl->gl_state == LM_ST_DEFERRED;
 168}
 169
 170static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
 171{
 172        return gl->gl_state == LM_ST_SHARED;
 173}
 174
 175static inline struct address_space *gfs2_glock2aspace(struct gfs2_glock *gl)
 176{
 177        if (gl->gl_ops->go_flags & GLOF_ASPACE)
 178                return (struct address_space *)(gl + 1);
 179        return NULL;
 180}
 181
 182extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 183                          const struct gfs2_glock_operations *glops,
 184                          int create, struct gfs2_glock **glp);
 185extern void gfs2_glock_hold(struct gfs2_glock *gl);
 186extern void gfs2_glock_put(struct gfs2_glock *gl);
 187extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
 188extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
 189                             u16 flags, struct gfs2_holder *gh);
 190extern void gfs2_holder_reinit(unsigned int state, u16 flags,
 191                               struct gfs2_holder *gh);
 192extern void gfs2_holder_uninit(struct gfs2_holder *gh);
 193extern int gfs2_glock_nq(struct gfs2_holder *gh);
 194extern int gfs2_glock_poll(struct gfs2_holder *gh);
 195extern int gfs2_glock_wait(struct gfs2_holder *gh);
 196extern int gfs2_glock_async_wait(unsigned int num_gh, struct gfs2_holder *ghs);
 197extern void gfs2_glock_dq(struct gfs2_holder *gh);
 198extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
 199extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
 200extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
 201                             const struct gfs2_glock_operations *glops,
 202                             unsigned int state, u16 flags,
 203                             struct gfs2_holder *gh);
 204extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 205extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 206extern void gfs2_dump_glock(struct seq_file *seq, struct gfs2_glock *gl,
 207                            bool fsid);
 208#define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) {              \
 209                        gfs2_dump_glock(NULL, gl, true);        \
 210                        BUG(); } } while(0)
 211extern __printf(2, 3)
 212void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
 213
 214/**
 215 * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
 216 * @gl: the glock
 217 * @state: the state we're requesting
 218 * @flags: the modifier flags
 219 * @gh: the holder structure
 220 *
 221 * Returns: 0, GLR_*, or errno
 222 */
 223
 224static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
 225                                     unsigned int state, u16 flags,
 226                                     struct gfs2_holder *gh)
 227{
 228        int error;
 229
 230        gfs2_holder_init(gl, state, flags, gh);
 231
 232        error = gfs2_glock_nq(gh);
 233        if (error)
 234                gfs2_holder_uninit(gh);
 235
 236        return error;
 237}
 238
 239extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
 240extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
 241extern bool gfs2_queue_delete_work(struct gfs2_glock *gl, unsigned long delay);
 242extern void gfs2_cancel_delete_work(struct gfs2_glock *gl);
 243extern bool gfs2_delete_work_queued(const struct gfs2_glock *gl);
 244extern void gfs2_flush_delete_work(struct gfs2_sbd *sdp);
 245extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
 246extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
 247extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
 248extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
 249extern void gfs2_glock_free(struct gfs2_glock *gl);
 250
 251extern int __init gfs2_glock_init(void);
 252extern void gfs2_glock_exit(void);
 253
 254extern int gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
 255extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
 256extern int gfs2_register_debugfs(void);
 257extern void gfs2_unregister_debugfs(void);
 258
 259extern const struct lm_lockops gfs2_dlm_ops;
 260
 261static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
 262{
 263        gh->gh_gl = NULL;
 264}
 265
 266static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
 267{
 268        return gh->gh_gl;
 269}
 270
 271static inline bool gfs2_holder_queued(struct gfs2_holder *gh)
 272{
 273        return !list_empty(&gh->gh_list);
 274}
 275
 276/**
 277 * glock_set_object - set the gl_object field of a glock
 278 * @gl: the glock
 279 * @object: the object
 280 */
 281static inline void glock_set_object(struct gfs2_glock *gl, void *object)
 282{
 283        spin_lock(&gl->gl_lockref.lock);
 284        if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL))
 285                gfs2_dump_glock(NULL, gl, true);
 286        gl->gl_object = object;
 287        spin_unlock(&gl->gl_lockref.lock);
 288}
 289
 290/**
 291 * glock_clear_object - clear the gl_object field of a glock
 292 * @gl: the glock
 293 * @object: the object
 294 *
 295 * I'd love to similarly add this:
 296 *      else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object))
 297 *              gfs2_dump_glock(NULL, gl, true);
 298 * Unfortunately, that's not possible because as soon as gfs2_delete_inode
 299 * frees the block in the rgrp, another process can reassign it for an I_NEW
 300 * inode in gfs2_create_inode because that calls new_inode, not gfs2_iget.
 301 * That means gfs2_delete_inode may subsequently try to call this function
 302 * for a glock that's already pointing to a brand new inode. If we clear the
 303 * new inode's gl_object, we'll introduce metadata corruption. Function
 304 * gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also
 305 * tries to clear gl_object, so it's more than just gfs2_delete_inode.
 306 *
 307 */
 308static inline void glock_clear_object(struct gfs2_glock *gl, void *object)
 309{
 310        spin_lock(&gl->gl_lockref.lock);
 311        if (gl->gl_object == object)
 312                gl->gl_object = NULL;
 313        spin_unlock(&gl->gl_lockref.lock);
 314}
 315
 316extern void gfs2_inode_remember_delete(struct gfs2_glock *gl, u64 generation);
 317extern bool gfs2_inode_already_deleted(struct gfs2_glock *gl, u64 generation);
 318
 319#endif /* __GLOCK_DOT_H__ */
 320