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
  20 enum {
  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
 123 struct 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
 138 extern struct workqueue_struct *gfs2_delete_workqueue;
 139 static 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;
 154 out:
 155         spin_unlock(&gl->gl_lockref.lock);
 156
 157         return gh;
 158 }
 159
 160 static inline int gfs2_glock_is_held_excl(struct gfs2_glock *gl)
 161 {
 162         return gl->gl_state == LM_ST_EXCLUSIVE;
 163 }
 164
 165 static inline int gfs2_glock_is_held_dfrd(struct gfs2_glock *gl)
 166 {
 167         return gl->gl_state == LM_ST_DEFERRED;
 168 }
 169
 170 static inline int gfs2_glock_is_held_shrd(struct gfs2_glock *gl)
 171 {
 172         return gl->gl_state == LM_ST_SHARED;
 173 }
 174
 175 static 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
 182 extern int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 183                           const struct gfs2_glock_operations *glops,
 184                           int create, struct gfs2_glock **glp);
 185 extern void gfs2_glock_hold(struct gfs2_glock *gl);
 186 extern void gfs2_glock_put(struct gfs2_glock *gl);
 187 extern void gfs2_glock_queue_put(struct gfs2_glock *gl);
 188 extern void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state,
 189                              u16 flags, struct gfs2_holder *gh);
 190 extern void gfs2_holder_reinit(unsigned int state, u16 flags,
 191                                struct gfs2_holder *gh);
 192 extern void gfs2_holder_uninit(struct gfs2_holder *gh);
 193 extern int gfs2_glock_nq(struct gfs2_holder *gh);
 194 extern int gfs2_glock_poll(struct gfs2_holder *gh);
 195 extern int gfs2_glock_wait(struct gfs2_holder *gh);
 196 extern void gfs2_glock_dq(struct gfs2_holder *gh);
 197 extern void gfs2_glock_dq_wait(struct gfs2_holder *gh);
 198 extern void gfs2_glock_dq_uninit(struct gfs2_holder *gh);
 199 extern int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
 200                              const struct gfs2_glock_operations *glops,
 201                              unsigned int state, u16 flags,
 202                              struct gfs2_holder *gh);
 203 extern int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 204 extern void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs);
 205 extern void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl);
 206 #define GLOCK_BUG_ON(gl,x) do { if (unlikely(x)) { gfs2_dump_glock(NULL, gl); BUG(); } } while(0)
 207 extern __printf(2, 3)
 208 void 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
 220 static inline int gfs2_glock_nq_init(struct gfs2_glock *gl,
 221                                      unsigned int state, u16 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
 235 extern void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state);
 236 extern void gfs2_glock_complete(struct gfs2_glock *gl, int ret);
 237 extern void gfs2_gl_hash_clear(struct gfs2_sbd *sdp);
 238 extern void gfs2_glock_finish_truncate(struct gfs2_inode *ip);
 239 extern void gfs2_glock_thaw(struct gfs2_sbd *sdp);
 240 extern void gfs2_glock_add_to_lru(struct gfs2_glock *gl);
 241 extern void gfs2_glock_free(struct gfs2_glock *gl);
 242
 243 extern int __init gfs2_glock_init(void);
 244 extern void gfs2_glock_exit(void);
 245
 246 extern int gfs2_create_debugfs_file(struct gfs2_sbd *sdp);
 247 extern void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp);
 248 extern int gfs2_register_debugfs(void);
 249 extern void gfs2_unregister_debugfs(void);
 250
 251 extern const struct lm_lockops gfs2_dlm_ops;
 252
 253 static inline void gfs2_holder_mark_uninitialized(struct gfs2_holder *gh)
 254 {
 255         gh->gh_gl = NULL;
 256 }
 257
 258 static inline bool gfs2_holder_initialized(struct gfs2_holder *gh)
 259 {
 260         return gh->gh_gl;
 261 }
 262
 263 /**
 264  * glock_set_object - set the gl_object field of a glock
 265  * @gl: the glock
 266  * @object: the object
 267  */
 268 static inline void glock_set_object(struct gfs2_glock *gl, void *object)
 269 {
 270         spin_lock(&gl->gl_lockref.lock);
 271         if (gfs2_assert_warn(gl->gl_name.ln_sbd, gl->gl_object == NULL))
 272                 gfs2_dump_glock(NULL, gl);
 273         gl->gl_object = object;
 274         spin_unlock(&gl->gl_lockref.lock);
 275 }
 276
 277 /**
 278  * glock_clear_object - clear the gl_object field of a glock
 279  * @gl: the glock
 280  * @object: the object
 281  *
 282  * I'd love to similarly add this:
 283  *      else if (gfs2_assert_warn(gl->gl_sbd, gl->gl_object == object))
 284  *              gfs2_dump_glock(NULL, gl);
 285  * Unfortunately, that's not possible because as soon as gfs2_delete_inode
 286  * frees the block in the rgrp, another process can reassign it for an I_NEW
 287  * inode in gfs2_create_inode because that calls new_inode, not gfs2_iget.
 288  * That means gfs2_delete_inode may subsequently try to call this function
 289  * for a glock that's already pointing to a brand new inode. If we clear the
 290  * new inode's gl_object, we'll introduce metadata corruption. Function
 291  * gfs2_delete_inode calls clear_inode which calls gfs2_clear_inode which also
 292  * tries to clear gl_object, so it's more than just gfs2_delete_inode.
 293  *
 294  */
 295 static inline void glock_clear_object(struct gfs2_glock *gl, void *object)
 296 {
 297         spin_lock(&gl->gl_lockref.lock);
 298         if (gl->gl_object == object)
 299                 gl->gl_object = NULL;
 300         spin_unlock(&gl->gl_lockref.lock);
 301 }
 302
 303 #endif /* __GLOCK_DOT_H__ */