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
  17 /* Options for hostdata parser */
  18
  19 enum {
  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             0x0001
  83 #define LM_FLAG_TRY_1CB         0x0002
  84 #define LM_FLAG_NOEXP           0x0004
  85 #define LM_FLAG_ANY             0x0008
  86 #define LM_FLAG_PRIORITY        0x0010
  87 #define GL_ASYNC                0x0040
  88 #define GL_EXACT                0x0080
  89 #define GL_SKIP                 0x0100
  90 #define GL_NOCACHE              0x0400
  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
 122 struct 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
 137 extern struct workqueue_struct *gfs2_delete_workqueue;
 138 static 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_lockref.lock);
 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;
 153 out:
 154         spin_unlock(&gl->gl_lockref.lock);
 155
 156         return gh;
 157 }
 158
 159 static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
 160 {
 161         return gl->gl_state == LM_ST_EXCLUSIVE;
 162 }
 163
 164 static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
 165 {
 166         return gl->gl_state == LM_ST_DEFERRED;
 167 }
 168
 169 static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
 170 {
 171         return gl->gl_state == LM_ST_SHARED;
 172 }
 173
 174 static 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
 181 extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 182                           const struct gfs2_glock_operations *glops,
 183                           int create, struct gfs2_glock **glp);
 184 extern void gfs2_glock_put(struct gfs2_glock *gl);
 185 extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
 186                              u16 flags, struct gfs2_holder *gh);
 187 extern void gfs2_holder_reinit(unsigned int state, u16 flags,
 188                                struct gfs2_holder *gh);
 189 extern void gfs2_holder_uninit(struct gfs2_holder *gh);
 190 extern int gfs2_glock_nq(struct gfs2_holder *gh);
 191 extern int gfs2_glock_poll(struct gfs2_holder *gh);
 192 extern int gfs2_glock_wait(struct gfs2_holder *gh);
 193 extern void gfs2_glock_dq(struct gfs2_holder *gh);
 194 extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
 195 extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
 196 extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
 197                              const struct gfs2_glock_operations *glops,
 198                              unsigned int state, u16 flags,
 199                              struct gfs2_holder *gh);
 200 extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 201 extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 202 extern void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl);
 203 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { gfs2_dump_glock(NULL, gl); BUG(); } } while(0)
 204 extern __printf(2, 3)
 205 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...);
 206
 207 /**
 208  * gfs2_glock_nq_init - initialize a holder and enqueue it on a glock
 209  * @gl: the glock
 210  * @state: the state we're requesting
 211  * @flags: the modifier flags
 212  * @gh: the holder structure
 213  *
 214  * Returns: 0, GLR_*, or errno
 215  */
 216
 217 static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
 218                                      unsigned int state, u16 flags,
 219                                      struct gfs2_holder *gh)
 220 {
 221         int error;
 222
 223         gfs2_holder_init(gl, state, flags, gh);
 224
 225         error = gfs2_glock_nq(gh);
 226         if (error)
 227                 gfs2_holder_uninit(gh);
 228
 229         return error;
 230 }
 231
 232 extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
 233 extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
 234 extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
 235 extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
 236 extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
 237 extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
 238 extern void gfs2_glock_free(struct gfs2_glock *gl);
 239
 240 extern int __init gfs2_glock_init(void);
 241 extern void gfs2_glock_exit(void);
 242
 243 extern int gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
 244 extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
 245 extern int gfs2_register_debugfs(void);
 246 extern void gfs2_unregister_debugfs(void);
 247
 248 extern const struct lm_lockops gfs2_dlm_ops;
 249
 250 static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
 251 {
 252         gh->gh_gl = NULL;
 253 }
 254
 255 static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
 256 {
 257         return gh->gh_gl;
 258 }
 259
 260 static inline void glock_set_object(struct gfs2_glock *gl, void *object)
 261 {
 262         spin_lock(&gl->gl_lockref.lock);
 263         gl->gl_object = object;
 264         spin_unlock(&gl->gl_lockref.lock);
 265 }
 266
 267 #endif /* __GLOCK_DOT_H__ */