fs/gfs2/glock.c

   1 /*
   2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
   3  * Copyright (C) 2004-2008 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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include <linux/sched.h>
  13 #include <linux/slab.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/buffer_head.h>
  16 #include <linux/delay.h>
  17 #include <linux/sort.h>
  18 #include <linux/jhash.h>
  19 #include <linux/kallsyms.h>
  20 #include <linux/gfs2_ondisk.h>
  21 #include <linux/list.h>
  22 #include <linux/wait.h>
  23 #include <linux/module.h>
  24 #include <asm/uaccess.h>
  25 #include <linux/seq_file.h>
  26 #include <linux/debugfs.h>
  27 #include <linux/kthread.h>
  28 #include <linux/freezer.h>
  29 #include <linux/workqueue.h>
  30 #include <linux/jiffies.h>
  31 #include <linux/rcupdate.h>
  32 #include <linux/rculist_bl.h>
  33 #include <linux/bit_spinlock.h>
  34 #include <linux/percpu.h>
  35 #include <linux/list_sort.h>
  36 #include <linux/lockref.h>
  37 #include <linux/rhashtable.h>
  38
  39 #include "gfs2.h"
  40 #include "incore.h"
  41 #include "glock.h"
  42 #include "glops.h"
  43 #include "inode.h"
  44 #include "lops.h"
  45 #include "meta_io.h"
  46 #include "quota.h"
  47 #include "super.h"
  48 #include "util.h"
  49 #include "bmap.h"
  50 #define CREATE_TRACE_POINTS
  51 #include "trace_gfs2.h"
  52
  53 struct gfs2_glock_iter {
  54         struct gfs2_sbd *sdp;           /* incore superblock           */
  55         struct rhashtable_iter hti;     /* rhashtable iterator         */
  56         struct gfs2_glock *gl;          /* current glock struct        */
  57         loff_t last_pos;                /* last position               */
  58 };
  59
  60 typedef void (*glock_examiner) (struct gfs2_glock * gl);
  61
  62 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
  63
  64 static struct dentry *gfs2_root;
  65 static struct workqueue_struct *glock_workqueue;
  66 struct workqueue_struct *gfs2_delete_workqueue;
  67 static LIST_HEAD(lru_list);
  68 static atomic_t lru_count = ATOMIC_INIT(0);
  69 static DEFINE_SPINLOCK(lru_lock);
  70
  71 #define GFS2_GL_HASH_SHIFT      15
  72 #define GFS2_GL_HASH_SIZE       (1 << GFS2_GL_HASH_SHIFT)
  73
  74 static struct rhashtable_params ht_parms = {
  75         .nelem_hint = GFS2_GL_HASH_SIZE * 3 / 4,
  76         .key_len = sizeof(struct lm_lockname),
  77         .key_offset = offsetof(struct gfs2_glock, gl_name),
  78         .head_offset = offsetof(struct gfs2_glock, gl_node),
  79 };
  80
  81 static struct rhashtable gl_hash_table;
  82
  83 static void gfs2_glock_dealloc(struct rcu_head *rcu)
  84 {
  85         struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
  86
  87         if (gl->gl_ops->go_flags & GLOF_ASPACE) {
  88                 kmem_cache_free(gfs2_glock_aspace_cachep, gl);
  89         } else {
  90                 kfree(gl->gl_lksb.sb_lvbptr);
  91                 kmem_cache_free(gfs2_glock_cachep, gl);
  92         }
  93 }
  94
  95 void gfs2_glock_free(struct gfs2_glock *gl)
  96 {
  97         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
  98
  99         call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
 100         if (atomic_dec_and_test(&sdp->sd_glock_disposal))
 101                 wake_up(&sdp->sd_glock_wait);
 102 }
 103
 104 /**
 105  * gfs2_glock_hold() - increment reference count on glock
 106  * @gl: The glock to hold
 107  *
 108  */
 109
 110 static void gfs2_glock_hold(struct gfs2_glock *gl)
 111 {
 112         GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
 113         lockref_get(&gl->gl_lockref);
 114 }
 115
 116 /**
 117  * demote_ok - Check to see if it's ok to unlock a glock
 118  * @gl: the glock
 119  *
 120  * Returns: 1 if it's ok
 121  */
 122
 123 static int demote_ok(const struct gfs2_glock *gl)
 124 {
 125         const struct gfs2_glock_operations *glops = gl->gl_ops;
 126
 127         if (gl->gl_state == LM_ST_UNLOCKED)
 128                 return 0;
 129         if (!list_empty(&gl->gl_holders))
 130                 return 0;
 131         if (glops->go_demote_ok)
 132                 return glops->go_demote_ok(gl);
 133         return 1;
 134 }
 135
 136
 137 void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
 138 {
 139         spin_lock(&lru_lock);
 140
 141         if (!list_empty(&gl->gl_lru))
 142                 list_del_init(&gl->gl_lru);
 143         else
 144                 atomic_inc(&lru_count);
 145
 146         list_add_tail(&gl->gl_lru, &lru_list);
 147         set_bit(GLF_LRU, &gl->gl_flags);
 148         spin_unlock(&lru_lock);
 149 }
 150
 151 static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
 152 {
 153         spin_lock(&lru_lock);
 154         if (!list_empty(&gl->gl_lru)) {
 155                 list_del_init(&gl->gl_lru);
 156                 atomic_dec(&lru_count);
 157                 clear_bit(GLF_LRU, &gl->gl_flags);
 158         }
 159         spin_unlock(&lru_lock);
 160 }
 161
 162 /**
 163  * gfs2_glock_put() - Decrement reference count on glock
 164  * @gl: The glock to put
 165  *
 166  */
 167
 168 void gfs2_glock_put(struct gfs2_glock *gl)
 169 {
 170         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 171         struct address_space *mapping = gfs2_glock2aspace(gl);
 172
 173         if (lockref_put_or_lock(&gl->gl_lockref))
 174                 return;
 175
 176         lockref_mark_dead(&gl->gl_lockref);
 177
 178         gfs2_glock_remove_from_lru(gl);
 179         spin_unlock(&gl->gl_lockref.lock);
 180         rhashtable_remove_fast(&gl_hash_table, &gl->gl_node, ht_parms);
 181         GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
 182         GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
 183         trace_gfs2_glock_put(gl);
 184         sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
 185 }
 186
 187 /**
 188  * may_grant - check if its ok to grant a new lock
 189  * @gl: The glock
 190  * @gh: The lock request which we wish to grant
 191  *
 192  * Returns: true if its ok to grant the lock
 193  */
 194
 195 static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
 196 {
 197         const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
 198         if ((gh->gh_state == LM_ST_EXCLUSIVE ||
 199              gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
 200                 return 0;
 201         if (gl->gl_state == gh->gh_state)
 202                 return 1;
 203         if (gh->gh_flags & GL_EXACT)
 204                 return 0;
 205         if (gl->gl_state == LM_ST_EXCLUSIVE) {
 206                 if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
 207                         return 1;
 208                 if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
 209                         return 1;
 210         }
 211         if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
 212                 return 1;
 213         return 0;
 214 }
 215
 216 static void gfs2_holder_wake(struct gfs2_holder *gh)
 217 {
 218         clear_bit(HIF_WAIT, &gh->gh_iflags);
 219         smp_mb__after_atomic();
 220         wake_up_bit(&gh->gh_iflags, HIF_WAIT);
 221 }
 222
 223 /**
 224  * do_error - Something unexpected has happened during a lock request
 225  *
 226  */
 227
 228 static inline void do_error(struct gfs2_glock *gl, const int ret)
 229 {
 230         struct gfs2_holder *gh, *tmp;
 231
 232         list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
 233                 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
 234                         continue;
 235                 if (ret & LM_OUT_ERROR)
 236                         gh->gh_error = -EIO;
 237                 else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
 238                         gh->gh_error = GLR_TRYFAILED;
 239                 else
 240                         continue;
 241                 list_del_init(&gh->gh_list);
 242                 trace_gfs2_glock_queue(gh, 0);
 243                 gfs2_holder_wake(gh);
 244         }
 245 }
 246
 247 /**
 248  * do_promote - promote as many requests as possible on the current queue
 249  * @gl: The glock
 250  *
 251  * Returns: 1 if there is a blocked holder at the head of the list, or 2
 252  *          if a type specific operation is underway.
 253  */
 254
 255 static int do_promote(struct gfs2_glock *gl)
 256 __releases(&gl->gl_lockref.lock)
 257 __acquires(&gl->gl_lockref.lock)
 258 {
 259         const struct gfs2_glock_operations *glops = gl->gl_ops;
 260         struct gfs2_holder *gh, *tmp;
 261         int ret;
 262
 263 restart:
 264         list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
 265                 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
 266                         continue;
 267                 if (may_grant(gl, gh)) {
 268                         if (gh->gh_list.prev == &gl->gl_holders &&
 269                             glops->go_lock) {
 270                                 spin_unlock(&gl->gl_lockref.lock);
 271                                 /* FIXME: eliminate this eventually */
 272                                 ret = glops->go_lock(gh);
 273                                 spin_lock(&gl->gl_lockref.lock);
 274                                 if (ret) {
 275                                         if (ret == 1)
 276                                                 return 2;
 277                                         gh->gh_error = ret;
 278                                         list_del_init(&gh->gh_list);
 279                                         trace_gfs2_glock_queue(gh, 0);
 280                                         gfs2_holder_wake(gh);
 281                                         goto restart;
 282                                 }
 283                                 set_bit(HIF_HOLDER, &gh->gh_iflags);
 284                                 trace_gfs2_promote(gh, 1);
 285                                 gfs2_holder_wake(gh);
 286                                 goto restart;
 287                         }
 288                         set_bit(HIF_HOLDER, &gh->gh_iflags);
 289                         trace_gfs2_promote(gh, 0);
 290                         gfs2_holder_wake(gh);
 291                         continue;
 292                 }
 293                 if (gh->gh_list.prev == &gl->gl_holders)
 294                         return 1;
 295                 do_error(gl, 0);
 296                 break;
 297         }
 298         return 0;
 299 }
 300
 301 /**
 302  * find_first_waiter - find the first gh that's waiting for the glock
 303  * @gl: the glock
 304  */
 305
 306 static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
 307 {
 308         struct gfs2_holder *gh;
 309
 310         list_for_each_entry(gh, &gl->gl_holders, gh_list) {
 311                 if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
 312                         return gh;
 313         }
 314         return NULL;
 315 }
 316
 317 /**
 318  * state_change - record that the glock is now in a different state
 319  * @gl: the glock
 320  * @new_state the new state
 321  *
 322  */
 323
 324 static void state_change(struct gfs2_glock *gl, unsigned int new_state)
 325 {
 326         int held1, held2;
 327
 328         held1 = (gl->gl_state != LM_ST_UNLOCKED);
 329         held2 = (new_state != LM_ST_UNLOCKED);
 330
 331         if (held1 != held2) {
 332                 GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
 333                 if (held2)
 334                         gl->gl_lockref.count++;
 335                 else
 336                         gl->gl_lockref.count--;
 337         }
 338         if (held1 && held2 && list_empty(&gl->gl_holders))
 339                 clear_bit(GLF_QUEUED, &gl->gl_flags);
 340
 341         if (new_state != gl->gl_target)
 342                 /* shorten our minimum hold time */
 343                 gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
 344                                        GL_GLOCK_MIN_HOLD);
 345         gl->gl_state = new_state;
 346         gl->gl_tchange = jiffies;
 347 }
 348
 349 static void gfs2_demote_wake(struct gfs2_glock *gl)
 350 {
 351         gl->gl_demote_state = LM_ST_EXCLUSIVE;
 352         clear_bit(GLF_DEMOTE, &gl->gl_flags);
 353         smp_mb__after_atomic();
 354         wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
 355 }
 356
 357 /**
 358  * finish_xmote - The DLM has replied to one of our lock requests
 359  * @gl: The glock
 360  * @ret: The status from the DLM
 361  *
 362  */
 363
 364 static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
 365 {
 366         const struct gfs2_glock_operations *glops = gl->gl_ops;
 367         struct gfs2_holder *gh;
 368         unsigned state = ret & LM_OUT_ST_MASK;
 369         int rv;
 370
 371         spin_lock(&gl->gl_lockref.lock);
 372         trace_gfs2_glock_state_change(gl, state);
 373         state_change(gl, state);
 374         gh = find_first_waiter(gl);
 375
 376         /* Demote to UN request arrived during demote to SH or DF */
 377         if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
 378             state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
 379                 gl->gl_target = LM_ST_UNLOCKED;
 380
 381         /* Check for state != intended state */
 382         if (unlikely(state != gl->gl_target)) {
 383                 if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
 384                         /* move to back of queue and try next entry */
 385                         if (ret & LM_OUT_CANCELED) {
 386                                 if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
 387                                         list_move_tail(&gh->gh_list, &gl->gl_holders);
 388                                 gh = find_first_waiter(gl);
 389                                 gl->gl_target = gh->gh_state;
 390                                 goto retry;
 391                         }
 392                         /* Some error or failed "try lock" - report it */
 393                         if ((ret & LM_OUT_ERROR) ||
 394                             (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
 395                                 gl->gl_target = gl->gl_state;
 396                                 do_error(gl, ret);
 397                                 goto out;
 398                         }
 399                 }
 400                 switch(state) {
 401                 /* Unlocked due to conversion deadlock, try again */
 402                 case LM_ST_UNLOCKED:
 403 retry:
 404                         do_xmote(gl, gh, gl->gl_target);
 405                         break;
 406                 /* Conversion fails, unlock and try again */
 407                 case LM_ST_SHARED:
 408                 case LM_ST_DEFERRED:
 409                         do_xmote(gl, gh, LM_ST_UNLOCKED);
 410                         break;
 411                 default: /* Everything else */
 412                         pr_err("wanted %u got %u\n", gl->gl_target, state);
 413                         GLOCK_BUG_ON(gl, 1);
 414                 }
 415                 spin_unlock(&gl->gl_lockref.lock);
 416                 return;
 417         }
 418
 419         /* Fast path - we got what we asked for */
 420         if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
 421                 gfs2_demote_wake(gl);
 422         if (state != LM_ST_UNLOCKED) {
 423                 if (glops->go_xmote_bh) {
 424                         spin_unlock(&gl->gl_lockref.lock);
 425                         rv = glops->go_xmote_bh(gl, gh);
 426                         spin_lock(&gl->gl_lockref.lock);
 427                         if (rv) {
 428                                 do_error(gl, rv);
 429                                 goto out;
 430                         }
 431                 }
 432                 rv = do_promote(gl);
 433                 if (rv == 2)
 434                         goto out_locked;
 435         }
 436 out:
 437         clear_bit(GLF_LOCK, &gl->gl_flags);
 438 out_locked:
 439         spin_unlock(&gl->gl_lockref.lock);
 440 }
 441
 442 /**
 443  * do_xmote - Calls the DLM to change the state of a lock
 444  * @gl: The lock state
 445  * @gh: The holder (only for promotes)
 446  * @target: The target lock state
 447  *
 448  */
 449
 450 static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
 451 __releases(&gl->gl_lockref.lock)
 452 __acquires(&gl->gl_lockref.lock)
 453 {
 454         const struct gfs2_glock_operations *glops = gl->gl_ops;
 455         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 456         unsigned int lck_flags = gh ? gh->gh_flags : 0;
 457         int ret;
 458
 459         lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
 460                       LM_FLAG_PRIORITY);
 461         GLOCK_BUG_ON(gl, gl->gl_state == target);
 462         GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
 463         if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
 464             glops->go_inval) {
 465                 set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
 466                 do_error(gl, 0); /* Fail queued try locks */
 467         }
 468         gl->gl_req = target;
 469         set_bit(GLF_BLOCKING, &gl->gl_flags);
 470         if ((gl->gl_req == LM_ST_UNLOCKED) ||
 471             (gl->gl_state == LM_ST_EXCLUSIVE) ||
 472             (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
 473                 clear_bit(GLF_BLOCKING, &gl->gl_flags);
 474         spin_unlock(&gl->gl_lockref.lock);
 475         if (glops->go_sync)
 476                 glops->go_sync(gl);
 477         if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
 478                 glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
 479         clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
 480
 481         gfs2_glock_hold(gl);
 482         if (sdp->sd_lockstruct.ls_ops->lm_lock) {
 483                 /* lock_dlm */
 484                 ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
 485                 if (ret) {
 486                         pr_err("lm_lock ret %d\n", ret);
 487                         GLOCK_BUG_ON(gl, 1);
 488                 }
 489         } else { /* lock_nolock */
 490                 finish_xmote(gl, target);
 491                 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
 492                         gfs2_glock_put(gl);
 493         }
 494
 495         spin_lock(&gl->gl_lockref.lock);
 496 }
 497
 498 /**
 499  * find_first_holder - find the first "holder" gh
 500  * @gl: the glock
 501  */
 502
 503 static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
 504 {
 505         struct gfs2_holder *gh;
 506
 507         if (!list_empty(&gl->gl_holders)) {
 508                 gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
 509                 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
 510                         return gh;
 511         }
 512         return NULL;
 513 }
 514
 515 /**
 516  * run_queue - do all outstanding tasks related to a glock
 517  * @gl: The glock in question
 518  * @nonblock: True if we must not block in run_queue
 519  *
 520  */
 521
 522 static void run_queue(struct gfs2_glock *gl, const int nonblock)
 523 __releases(&gl->gl_lockref.lock)
 524 __acquires(&gl->gl_lockref.lock)
 525 {
 526         struct gfs2_holder *gh = NULL;
 527         int ret;
 528
 529         if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
 530                 return;
 531
 532         GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
 533
 534         if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
 535             gl->gl_demote_state != gl->gl_state) {
 536                 if (find_first_holder(gl))
 537                         goto out_unlock;
 538                 if (nonblock)
 539                         goto out_sched;
 540                 set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
 541                 GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
 542                 gl->gl_target = gl->gl_demote_state;
 543         } else {
 544                 if (test_bit(GLF_DEMOTE, &gl->gl_flags))
 545                         gfs2_demote_wake(gl);
 546                 ret = do_promote(gl);
 547                 if (ret == 0)
 548                         goto out_unlock;
 549                 if (ret == 2)
 550                         goto out;
 551                 gh = find_first_waiter(gl);
 552                 gl->gl_target = gh->gh_state;
 553                 if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
 554                         do_error(gl, 0); /* Fail queued try locks */
 555         }
 556         do_xmote(gl, gh, gl->gl_target);
 557 out:
 558         return;
 559
 560 out_sched:
 561         clear_bit(GLF_LOCK, &gl->gl_flags);
 562         smp_mb__after_atomic();
 563         gl->gl_lockref.count++;
 564         if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
 565                 gl->gl_lockref.count--;
 566         return;
 567
 568 out_unlock:
 569         clear_bit(GLF_LOCK, &gl->gl_flags);
 570         smp_mb__after_atomic();
 571         return;
 572 }
 573
 574 static void delete_work_func(struct work_struct *work)
 575 {
 576         struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
 577         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 578         struct gfs2_inode *ip;
 579         struct inode *inode;
 580         u64 no_addr = gl->gl_name.ln_number;
 581
 582         ip = gl->gl_object;
 583         /* Note: Unsafe to dereference ip as we don't hold right refs/locks */
 584
 585         if (ip)
 586                 inode = gfs2_ilookup(sdp->sd_vfs, no_addr, 1);
 587         else
 588                 inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
 589         if (inode && !IS_ERR(inode)) {
 590                 d_prune_aliases(inode);
 591                 iput(inode);
 592         }
 593         gfs2_glock_put(gl);
 594 }
 595
 596 static void glock_work_func(struct work_struct *work)
 597 {
 598         unsigned long delay = 0;
 599         struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
 600         int drop_ref = 0;
 601
 602         if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
 603                 finish_xmote(gl, gl->gl_reply);
 604                 drop_ref = 1;
 605         }
 606         spin_lock(&gl->gl_lockref.lock);
 607         if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
 608             gl->gl_state != LM_ST_UNLOCKED &&
 609             gl->gl_demote_state != LM_ST_EXCLUSIVE) {
 610                 unsigned long holdtime, now = jiffies;
 611
 612                 holdtime = gl->gl_tchange + gl->gl_hold_time;
 613                 if (time_before(now, holdtime))
 614                         delay = holdtime - now;
 615
 616                 if (!delay) {
 617                         clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
 618                         set_bit(GLF_DEMOTE, &gl->gl_flags);
 619                 }
 620         }
 621         run_queue(gl, 0);
 622         spin_unlock(&gl->gl_lockref.lock);
 623         if (!delay)
 624                 gfs2_glock_put(gl);
 625         else {
 626                 if (gl->gl_name.ln_type != LM_TYPE_INODE)
 627                         delay = 0;
 628                 if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
 629                         gfs2_glock_put(gl);
 630         }
 631         if (drop_ref)
 632                 gfs2_glock_put(gl);
 633 }
 634
 635 /**
 636  * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
 637  * @sdp: The GFS2 superblock
 638  * @number: the lock number
 639  * @glops: The glock_operations to use
 640  * @create: If 0, don't create the glock if it doesn't exist
 641  * @glp: the glock is returned here
 642  *
 643  * This does not lock a glock, just finds/creates structures for one.
 644  *
 645  * Returns: errno
 646  */
 647
 648 int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 649                    const struct gfs2_glock_operations *glops, int create,
 650                    struct gfs2_glock **glp)
 651 {
 652         struct super_block *s = sdp->sd_vfs;
 653         struct lm_lockname name = { .ln_number = number,
 654                                     .ln_type = glops->go_type,
 655                                     .ln_sbd = sdp };
 656         struct gfs2_glock *gl, *tmp = NULL;
 657         struct address_space *mapping;
 658         struct kmem_cache *cachep;
 659         int ret, tries = 0;
 660
 661         rcu_read_lock();
 662         gl = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
 663         if (gl && !lockref_get_not_dead(&gl->gl_lockref))
 664                 gl = NULL;
 665         rcu_read_unlock();
 666
 667         *glp = gl;
 668         if (gl)
 669                 return 0;
 670         if (!create)
 671                 return -ENOENT;
 672
 673         if (glops->go_flags & GLOF_ASPACE)
 674                 cachep = gfs2_glock_aspace_cachep;
 675         else
 676                 cachep = gfs2_glock_cachep;
 677         gl = kmem_cache_alloc(cachep, GFP_NOFS);
 678         if (!gl)
 679                 return -ENOMEM;
 680
 681         memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
 682
 683         if (glops->go_flags & GLOF_LVB) {
 684                 gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_NOFS);
 685                 if (!gl->gl_lksb.sb_lvbptr) {
 686                         kmem_cache_free(cachep, gl);
 687                         return -ENOMEM;
 688                 }
 689         }
 690
 691         atomic_inc(&sdp->sd_glock_disposal);
 692         gl->gl_node.next = NULL;
 693         gl->gl_flags = 0;
 694         gl->gl_name = name;
 695         gl->gl_lockref.count = 1;
 696         gl->gl_state = LM_ST_UNLOCKED;
 697         gl->gl_target = LM_ST_UNLOCKED;
 698         gl->gl_demote_state = LM_ST_EXCLUSIVE;
 699         gl->gl_ops = glops;
 700         gl->gl_dstamp = ktime_set(0, 0);
 701         preempt_disable();
 702         /* We use the global stats to estimate the initial per-glock stats */
 703         gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
 704         preempt_enable();
 705         gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
 706         gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
 707         gl->gl_tchange = jiffies;
 708         gl->gl_object = NULL;
 709         gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
 710         INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
 711         INIT_WORK(&gl->gl_delete, delete_work_func);
 712
 713         mapping = gfs2_glock2aspace(gl);
 714         if (mapping) {
 715                 mapping->a_ops = &gfs2_meta_aops;
 716                 mapping->host = s->s_bdev->bd_inode;
 717                 mapping->flags = 0;
 718                 mapping_set_gfp_mask(mapping, GFP_NOFS);
 719                 mapping->private_data = NULL;
 720                 mapping->writeback_index = 0;
 721         }
 722
 723 again:
 724         ret = rhashtable_lookup_insert_fast(&gl_hash_table, &gl->gl_node,
 725                                             ht_parms);
 726         if (ret == 0) {
 727                 *glp = gl;
 728                 return 0;
 729         }
 730
 731         if (ret == -EEXIST) {
 732                 ret = 0;
 733                 rcu_read_lock();
 734                 tmp = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
 735                 if (tmp == NULL || !lockref_get_not_dead(&tmp->gl_lockref)) {
 736                         if (++tries < 100) {
 737                                 rcu_read_unlock();
 738                                 cond_resched();
 739                                 goto again;
 740                         }
 741                         tmp = NULL;
 742                         ret = -ENOMEM;
 743                 }
 744                 rcu_read_unlock();
 745         } else {
 746                 WARN_ON_ONCE(ret);
 747         }
 748         kfree(gl->gl_lksb.sb_lvbptr);
 749         kmem_cache_free(cachep, gl);
 750         atomic_dec(&sdp->sd_glock_disposal);
 751         *glp = tmp;
 752
 753         return ret;
 754 }
 755
 756 /**
 757  * gfs2_holder_init - initialize a struct gfs2_holder in the default way
 758  * @gl: the glock
 759  * @state: the state we're requesting
 760  * @flags: the modifier flags
 761  * @gh: the holder structure
 762  *
 763  */
 764
 765 void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
 766                       struct gfs2_holder *gh)
 767 {
 768         INIT_LIST_HEAD(&gh->gh_list);
 769         gh->gh_gl = gl;
 770         gh->gh_ip = _RET_IP_;
 771         gh->gh_owner_pid = get_pid(task_pid(current));
 772         gh->gh_state = state;
 773         gh->gh_flags = flags;
 774         gh->gh_error = 0;
 775         gh->gh_iflags = 0;
 776         gfs2_glock_hold(gl);
 777 }
 778
 779 /**
 780  * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
 781  * @state: the state we're requesting
 782  * @flags: the modifier flags
 783  * @gh: the holder structure
 784  *
 785  * Don't mess with the glock.
 786  *
 787  */
 788
 789 void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
 790 {
 791         gh->gh_state = state;
 792         gh->gh_flags = flags;
 793         gh->gh_iflags = 0;
 794         gh->gh_ip = _RET_IP_;
 795         put_pid(gh->gh_owner_pid);
 796         gh->gh_owner_pid = get_pid(task_pid(current));
 797 }
 798
 799 /**
 800  * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
 801  * @gh: the holder structure
 802  *
 803  */
 804
 805 void gfs2_holder_uninit(struct gfs2_holder *gh)
 806 {
 807         put_pid(gh->gh_owner_pid);
 808         gfs2_glock_put(gh->gh_gl);
 809         gh->gh_gl = NULL;
 810         gh->gh_ip = 0;
 811 }
 812
 813 /**
 814  * gfs2_glock_wait - wait on a glock acquisition
 815  * @gh: the glock holder
 816  *
 817  * Returns: 0 on success
 818  */
 819
 820 int gfs2_glock_wait(struct gfs2_holder *gh)
 821 {
 822         unsigned long time1 = jiffies;
 823
 824         might_sleep();
 825         wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
 826         if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
 827                 /* Lengthen the minimum hold time. */
 828                 gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
 829                                               GL_GLOCK_HOLD_INCR,
 830                                               GL_GLOCK_MAX_HOLD);
 831         return gh->gh_error;
 832 }
 833
 834 /**
 835  * handle_callback - process a demote request
 836  * @gl: the glock
 837  * @state: the state the caller wants us to change to
 838  *
 839  * There are only two requests that we are going to see in actual
 840  * practise: LM_ST_SHARED and LM_ST_UNLOCKED
 841  */
 842
 843 static void handle_callback(struct gfs2_glock *gl, unsigned int state,
 844                             unsigned long delay, bool remote)
 845 {
 846         int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
 847
 848         set_bit(bit, &gl->gl_flags);
 849         if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
 850                 gl->gl_demote_state = state;
 851                 gl->gl_demote_time = jiffies;
 852         } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
 853                         gl->gl_demote_state != state) {
 854                 gl->gl_demote_state = LM_ST_UNLOCKED;
 855         }
 856         if (gl->gl_ops->go_callback)
 857                 gl->gl_ops->go_callback(gl, remote);
 858         trace_gfs2_demote_rq(gl, remote);
 859 }
 860
 861 void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
 862 {
 863         struct va_format vaf;
 864         va_list args;
 865
 866         va_start(args, fmt);
 867
 868         if (seq) {
 869                 seq_vprintf(seq, fmt, args);
 870         } else {
 871                 vaf.fmt = fmt;
 872                 vaf.va = &args;
 873
 874                 pr_err("%pV", &vaf);
 875         }
 876
 877         va_end(args);
 878 }
 879
 880 /**
 881  * add_to_queue - Add a holder to the wait queue (but look for recursion)
 882  * @gh: the holder structure to add
 883  *
 884  * Eventually we should move the recursive locking trap to a
 885  * debugging option or something like that. This is the fast
 886  * path and needs to have the minimum number of distractions.
 887  *
 888  */
 889
 890 static inline void add_to_queue(struct gfs2_holder *gh)
 891 __releases(&gl->gl_lockref.lock)
 892 __acquires(&gl->gl_lockref.lock)
 893 {
 894         struct gfs2_glock *gl = gh->gh_gl;
 895         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 896         struct list_head *insert_pt = NULL;
 897         struct gfs2_holder *gh2;
 898         int try_futile = 0;
 899
 900         BUG_ON(gh->gh_owner_pid == NULL);
 901         if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
 902                 BUG();
 903
 904         if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
 905                 if (test_bit(GLF_LOCK, &gl->gl_flags))
 906                         try_futile = !may_grant(gl, gh);
 907                 if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
 908                         goto fail;
 909         }
 910
 911         list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
 912                 if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
 913                     (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
 914                         goto trap_recursive;
 915                 if (try_futile &&
 916                     !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
 917 fail:
 918                         gh->gh_error = GLR_TRYFAILED;
 919                         gfs2_holder_wake(gh);
 920                         return;
 921                 }
 922                 if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
 923                         continue;
 924                 if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
 925                         insert_pt = &gh2->gh_list;
 926         }
 927         set_bit(GLF_QUEUED, &gl->gl_flags);
 928         trace_gfs2_glock_queue(gh, 1);
 929         gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
 930         gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
 931         if (likely(insert_pt == NULL)) {
 932                 list_add_tail(&gh->gh_list, &gl->gl_holders);
 933                 if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
 934                         goto do_cancel;
 935                 return;
 936         }
 937         list_add_tail(&gh->gh_list, insert_pt);
 938 do_cancel:
 939         gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
 940         if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
 941                 spin_unlock(&gl->gl_lockref.lock);
 942                 if (sdp->sd_lockstruct.ls_ops->lm_cancel)
 943                         sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
 944                 spin_lock(&gl->gl_lockref.lock);
 945         }
 946         return;
 947
 948 trap_recursive:
 949         pr_err("original: %pSR\n", (void *)gh2->gh_ip);
 950         pr_err("pid: %d\n", pid_nr(gh2->gh_owner_pid));
 951         pr_err("lock type: %d req lock state : %d\n",
 952                gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
 953         pr_err("new: %pSR\n", (void *)gh->gh_ip);
 954         pr_err("pid: %d\n", pid_nr(gh->gh_owner_pid));
 955         pr_err("lock type: %d req lock state : %d\n",
 956                gh->gh_gl->gl_name.ln_type, gh->gh_state);
 957         gfs2_dump_glock(NULL, gl);
 958         BUG();
 959 }
 960
 961 /**
 962  * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
 963  * @gh: the holder structure
 964  *
 965  * if (gh->gh_flags & GL_ASYNC), this never returns an error
 966  *
 967  * Returns: 0, GLR_TRYFAILED, or errno on failure
 968  */
 969
 970 int gfs2_glock_nq(struct gfs2_holder *gh)
 971 {
 972         struct gfs2_glock *gl = gh->gh_gl;
 973         struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 974         int error = 0;
 975
 976         if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 977                 return -EIO;
 978
 979         if (test_bit(GLF_LRU, &gl->gl_flags))
 980                 gfs2_glock_remove_from_lru(gl);
 981
 982         spin_lock(&gl->gl_lockref.lock);
 983         add_to_queue(gh);
 984         if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) &&
 985                      test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))) {
 986                 set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
 987                 gl->gl_lockref.count++;
 988                 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
 989                         gl->gl_lockref.count--;
 990         }
 991         run_queue(gl, 1);
 992         spin_unlock(&gl->gl_lockref.lock);
 993
 994         if (!(gh->gh_flags & GL_ASYNC))
 995                 error = gfs2_glock_wait(gh);
 996
 997         return error;
 998 }
 999
1000 /**
1001  * gfs2_glock_poll - poll to see if an async request has been completed
1002  * @gh: the holder
1003  *
1004  * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1005  */
1006
1007 int gfs2_glock_poll(struct gfs2_holder *gh)
1008 {
1009         return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1010 }
1011
1012 /**
1013  * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1014  * @gh: the glock holder
1015  *
1016  */
1017
1018 void gfs2_glock_dq(struct gfs2_holder *gh)
1019 {
1020         struct gfs2_glock *gl = gh->gh_gl;
1021         const struct gfs2_glock_operations *glops = gl->gl_ops;
1022         unsigned delay = 0;
1023         int fast_path = 0;
1024
1025         spin_lock(&gl->gl_lockref.lock);
1026         if (gh->gh_flags & GL_NOCACHE)
1027                 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1028
1029         list_del_init(&gh->gh_list);
1030         if (find_first_holder(gl) == NULL) {
1031                 if (glops->go_unlock) {
1032                         GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1033                         spin_unlock(&gl->gl_lockref.lock);
1034                         glops->go_unlock(gh);
1035                         spin_lock(&gl->gl_lockref.lock);
1036                         clear_bit(GLF_LOCK, &gl->gl_flags);
1037                 }
1038                 if (list_empty(&gl->gl_holders) &&
1039                     !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1040                     !test_bit(GLF_DEMOTE, &gl->gl_flags))
1041                         fast_path = 1;
1042         }
1043         if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl) &&
1044             (glops->go_flags & GLOF_LRU))
1045                 gfs2_glock_add_to_lru(gl);
1046
1047         trace_gfs2_glock_queue(gh, 0);
1048         spin_unlock(&gl->gl_lockref.lock);
1049         if (likely(fast_path))
1050                 return;
1051
1052         gfs2_glock_hold(gl);
1053         if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1054             !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1055             gl->gl_name.ln_type == LM_TYPE_INODE)
1056                 delay = gl->gl_hold_time;
1057         if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1058                 gfs2_glock_put(gl);
1059 }
1060
1061 void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1062 {
1063         struct gfs2_glock *gl = gh->gh_gl;
1064         gfs2_glock_dq(gh);
1065         might_sleep();
1066         wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE);
1067 }
1068
1069 /**
1070  * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1071  * @gh: the holder structure
1072  *
1073  */
1074
1075 void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1076 {
1077         gfs2_glock_dq(gh);
1078         gfs2_holder_uninit(gh);
1079 }
1080
1081 /**
1082  * gfs2_glock_nq_num - acquire a glock based on lock number
1083  * @sdp: the filesystem
1084  * @number: the lock number
1085  * @glops: the glock operations for the type of glock
1086  * @state: the state to acquire the glock in
1087  * @flags: modifier flags for the acquisition
1088  * @gh: the struct gfs2_holder
1089  *
1090  * Returns: errno
1091  */
1092
1093 int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1094                       const struct gfs2_glock_operations *glops,
1095                       unsigned int state, int flags, struct gfs2_holder *gh)
1096 {
1097         struct gfs2_glock *gl;
1098         int error;
1099
1100         error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1101         if (!error) {
1102                 error = gfs2_glock_nq_init(gl, state, flags, gh);
1103                 gfs2_glock_put(gl);
1104         }
1105
1106         return error;
1107 }
1108
1109 /**
1110  * glock_compare - Compare two struct gfs2_glock structures for sorting
1111  * @arg_a: the first structure
1112  * @arg_b: the second structure
1113  *
1114  */
1115
1116 static int glock_compare(const void *arg_a, const void *arg_b)
1117 {
1118         const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1119         const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1120         const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1121         const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1122
1123         if (a->ln_number > b->ln_number)
1124                 return 1;
1125         if (a->ln_number < b->ln_number)
1126                 return -1;
1127         BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1128         return 0;
1129 }
1130
1131 /**
1132  * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1133  * @num_gh: the number of structures
1134  * @ghs: an array of struct gfs2_holder structures
1135  *
1136  * Returns: 0 on success (all glocks acquired),
1137  *          errno on failure (no glocks acquired)
1138  */
1139
1140 static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1141                      struct gfs2_holder **p)
1142 {
1143         unsigned int x;
1144         int error = 0;
1145
1146         for (x = 0; x < num_gh; x++)
1147                 p[x] = &ghs[x];
1148
1149         sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1150
1151         for (x = 0; x < num_gh; x++) {
1152                 p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1153
1154                 error = gfs2_glock_nq(p[x]);
1155                 if (error) {
1156                         while (x--)
1157                                 gfs2_glock_dq(p[x]);
1158                         break;
1159                 }
1160         }
1161
1162         return error;
1163 }
1164
1165 /**
1166  * gfs2_glock_nq_m - acquire multiple glocks
1167  * @num_gh: the number of structures
1168  * @ghs: an array of struct gfs2_holder structures
1169  *
1170  *
1171  * Returns: 0 on success (all glocks acquired),
1172  *          errno on failure (no glocks acquired)
1173  */
1174
1175 int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1176 {
1177         struct gfs2_holder *tmp[4];
1178         struct gfs2_holder **pph = tmp;
1179         int error = 0;
1180
1181         switch(num_gh) {
1182         case 0:
1183                 return 0;
1184         case 1:
1185                 ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1186                 return gfs2_glock_nq(ghs);
1187         default:
1188                 if (num_gh <= 4)
1189                         break;
1190                 pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
1191                 if (!pph)
1192                         return -ENOMEM;
1193         }
1194
1195         error = nq_m_sync(num_gh, ghs, pph);
1196
1197         if (pph != tmp)
1198                 kfree(pph);
1199
1200         return error;
1201 }
1202
1203 /**
1204  * gfs2_glock_dq_m - release multiple glocks
1205  * @num_gh: the number of structures
1206  * @ghs: an array of struct gfs2_holder structures
1207  *
1208  */
1209
1210 void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1211 {
1212         while (num_gh--)
1213                 gfs2_glock_dq(&ghs[num_gh]);
1214 }
1215
1216 void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1217 {
1218         unsigned long delay = 0;
1219         unsigned long holdtime;
1220         unsigned long now = jiffies;
1221
1222         gfs2_glock_hold(gl);
1223         holdtime = gl->gl_tchange + gl->gl_hold_time;
1224         if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1225             gl->gl_name.ln_type == LM_TYPE_INODE) {
1226                 if (time_before(now, holdtime))
1227                         delay = holdtime - now;
1228                 if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1229                         delay = gl->gl_hold_time;
1230         }
1231
1232         spin_lock(&gl->gl_lockref.lock);
1233         handle_callback(gl, state, delay, true);
1234         spin_unlock(&gl->gl_lockref.lock);
1235         if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1236                 gfs2_glock_put(gl);
1237 }
1238
1239 /**
1240  * gfs2_should_freeze - Figure out if glock should be frozen
1241  * @gl: The glock in question
1242  *
1243  * Glocks are not frozen if (a) the result of the dlm operation is
1244  * an error, (b) the locking operation was an unlock operation or
1245  * (c) if there is a "noexp" flagged request anywhere in the queue
1246  *
1247  * Returns: 1 if freezing should occur, 0 otherwise
1248  */
1249
1250 static int gfs2_should_freeze(const struct gfs2_glock *gl)
1251 {
1252         const struct gfs2_holder *gh;
1253
1254         if (gl->gl_reply & ~LM_OUT_ST_MASK)
1255                 return 0;
1256         if (gl->gl_target == LM_ST_UNLOCKED)
1257                 return 0;
1258
1259         list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1260                 if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1261                         continue;
1262                 if (LM_FLAG_NOEXP & gh->gh_flags)
1263                         return 0;
1264         }
1265
1266         return 1;
1267 }
1268
1269 /**
1270  * gfs2_glock_complete - Callback used by locking
1271  * @gl: Pointer to the glock
1272  * @ret: The return value from the dlm
1273  *
1274  * The gl_reply field is under the gl_lockref.lock lock so that it is ok
1275  * to use a bitfield shared with other glock state fields.
1276  */
1277
1278 void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1279 {
1280         struct lm_lockstruct *ls = &gl->gl_name.ln_sbd->sd_lockstruct;
1281
1282         spin_lock(&gl->gl_lockref.lock);
1283         gl->gl_reply = ret;
1284
1285         if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1286                 if (gfs2_should_freeze(gl)) {
1287                         set_bit(GLF_FROZEN, &gl->gl_flags);
1288                         spin_unlock(&gl->gl_lockref.lock);
1289                         return;
1290                 }
1291         }
1292
1293         gl->gl_lockref.count++;
1294         set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1295         spin_unlock(&gl->gl_lockref.lock);
1296
1297         if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1298                 gfs2_glock_put(gl);
1299 }
1300
1301 static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
1302 {
1303         struct gfs2_glock *gla, *glb;
1304
1305         gla = list_entry(a, struct gfs2_glock, gl_lru);
1306         glb = list_entry(b, struct gfs2_glock, gl_lru);
1307
1308         if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1309                 return 1;
1310         if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1311                 return -1;
1312
1313         return 0;
1314 }
1315
1316 /**
1317  * gfs2_dispose_glock_lru - Demote a list of glocks
1318  * @list: The list to dispose of
1319  *
1320  * Disposing of glocks may involve disk accesses, so that here we sort
1321  * the glocks by number (i.e. disk location of the inodes) so that if
1322  * there are any such accesses, they'll be sent in order (mostly).
1323  *
1324  * Must be called under the lru_lock, but may drop and retake this
1325  * lock. While the lru_lock is dropped, entries may vanish from the
1326  * list, but no new entries will appear on the list (since it is
1327  * private)
1328  */
1329
1330 static void gfs2_dispose_glock_lru(struct list_head *list)
1331 __releases(&lru_lock)
1332 __acquires(&lru_lock)
1333 {
1334         struct gfs2_glock *gl;
1335
1336         list_sort(NULL, list, glock_cmp);
1337
1338         while(!list_empty(list)) {
1339                 gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1340                 list_del_init(&gl->gl_lru);
1341                 if (!spin_trylock(&gl->gl_lockref.lock)) {
1342 add_back_to_lru:
1343                         list_add(&gl->gl_lru, &lru_list);
1344                         atomic_inc(&lru_count);
1345                         continue;
1346                 }
1347                 if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1348                         spin_unlock(&gl->gl_lockref.lock);
1349                         goto add_back_to_lru;
1350                 }
1351                 clear_bit(GLF_LRU, &gl->gl_flags);
1352                 gl->gl_lockref.count++;
1353                 if (demote_ok(gl))
1354                         handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1355                 WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1356                 if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1357                         gl->gl_lockref.count--;
1358                 spin_unlock(&gl->gl_lockref.lock);
1359                 cond_resched_lock(&lru_lock);
1360         }
1361 }
1362
1363 /**
1364  * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1365  * @nr: The number of entries to scan
1366  *
1367  * This function selects the entries on the LRU which are able to
1368  * be demoted, and then kicks off the process by calling
1369  * gfs2_dispose_glock_lru() above.
1370  */
1371
1372 static long gfs2_scan_glock_lru(int nr)
1373 {
1374         struct gfs2_glock *gl;
1375         LIST_HEAD(skipped);
1376         LIST_HEAD(dispose);
1377         long freed = 0;
1378
1379         spin_lock(&lru_lock);
1380         while ((nr-- >= 0) && !list_empty(&lru_list)) {
1381                 gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1382
1383                 /* Test for being demotable */
1384                 if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
1385                         list_move(&gl->gl_lru, &dispose);
1386                         atomic_dec(&lru_count);
1387                         freed++;
1388                         continue;
1389                 }
1390
1391                 list_move(&gl->gl_lru, &skipped);
1392         }
1393         list_splice(&skipped, &lru_list);
1394         if (!list_empty(&dispose))
1395                 gfs2_dispose_glock_lru(&dispose);
1396         spin_unlock(&lru_lock);
1397
1398         return freed;
1399 }
1400
1401 static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
1402                                             struct shrink_control *sc)
1403 {
1404         if (!(sc->gfp_mask & __GFP_FS))
1405                 return SHRINK_STOP;
1406         return gfs2_scan_glock_lru(sc->nr_to_scan);
1407 }
1408
1409 static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
1410                                              struct shrink_control *sc)
1411 {
1412         return vfs_pressure_ratio(atomic_read(&lru_count));
1413 }
1414
1415 static struct shrinker glock_shrinker = {
1416         .seeks = DEFAULT_SEEKS,
1417         .count_objects = gfs2_glock_shrink_count,
1418         .scan_objects = gfs2_glock_shrink_scan,
1419 };
1420
1421 /**
1422  * examine_bucket - Call a function for glock in a hash bucket
1423  * @examiner: the function
1424  * @sdp: the filesystem
1425  * @bucket: the bucket
1426  *
1427  */
1428
1429 static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1430 {
1431         struct gfs2_glock *gl;
1432         struct rhash_head *pos, *next;
1433         const struct bucket_table *tbl;
1434         int i;
1435
1436         rcu_read_lock();
1437         tbl = rht_dereference_rcu(gl_hash_table.tbl, &gl_hash_table);
1438         for (i = 0; i < tbl->size; i++) {
1439                 rht_for_each_entry_safe(gl, pos, next, tbl, i, gl_node) {
1440                         if ((gl->gl_name.ln_sbd == sdp) &&
1441                             lockref_get_not_dead(&gl->gl_lockref))
1442                                 examiner(gl);
1443                 }
1444         }
1445         rcu_read_unlock();
1446         cond_resched();
1447 }
1448
1449 /**
1450  * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1451  * @gl: The glock to thaw
1452  *
1453  */
1454
1455 static void thaw_glock(struct gfs2_glock *gl)
1456 {
1457         if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1458                 goto out;
1459         set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1460         if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) {
1461 out:
1462                 gfs2_glock_put(gl);
1463         }
1464 }
1465
1466 /**
1467  * clear_glock - look at a glock and see if we can free it from glock cache
1468  * @gl: the glock to look at
1469  *
1470  */
1471
1472 static void clear_glock(struct gfs2_glock *gl)
1473 {
1474         gfs2_glock_remove_from_lru(gl);
1475
1476         spin_lock(&gl->gl_lockref.lock);
1477         if (gl->gl_state != LM_ST_UNLOCKED)
1478                 handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1479         spin_unlock(&gl->gl_lockref.lock);
1480         if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1481                 gfs2_glock_put(gl);
1482 }
1483
1484 /**
1485  * gfs2_glock_thaw - Thaw any frozen glocks
1486  * @sdp: The super block
1487  *
1488  */
1489
1490 void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1491 {
1492         glock_hash_walk(thaw_glock, sdp);
1493 }
1494
1495 static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1496 {
1497         spin_lock(&gl->gl_lockref.lock);
1498         gfs2_dump_glock(seq, gl);
1499         spin_unlock(&gl->gl_lockref.lock);
1500 }
1501
1502 static void dump_glock_func(struct gfs2_glock *gl)
1503 {
1504         dump_glock(NULL, gl);
1505 }
1506
1507 /**
1508  * gfs2_gl_hash_clear - Empty out the glock hash table
1509  * @sdp: the filesystem
1510  * @wait: wait until it's all gone
1511  *
1512  * Called when unmounting the filesystem.
1513  */
1514
1515 void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1516 {
1517         set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1518         flush_workqueue(glock_workqueue);
1519         glock_hash_walk(clear_glock, sdp);
1520         flush_workqueue(glock_workqueue);
1521         wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0);
1522         glock_hash_walk(dump_glock_func, sdp);
1523 }
1524
1525 void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1526 {
1527         struct gfs2_glock *gl = ip->i_gl;
1528         int ret;
1529
1530         ret = gfs2_truncatei_resume(ip);
1531         gfs2_assert_withdraw(gl->gl_name.ln_sbd, ret == 0);
1532
1533         spin_lock(&gl->gl_lockref.lock);
1534         clear_bit(GLF_LOCK, &gl->gl_flags);
1535         run_queue(gl, 1);
1536         spin_unlock(&gl->gl_lockref.lock);
1537 }
1538
1539 static const char *state2str(unsigned state)
1540 {
1541         switch(state) {
1542         case LM_ST_UNLOCKED:
1543                 return "UN";
1544         case LM_ST_SHARED:
1545                 return "SH";
1546         case LM_ST_DEFERRED:
1547                 return "DF";
1548         case LM_ST_EXCLUSIVE:
1549                 return "EX";
1550         }
1551         return "??";
1552 }
1553
1554 static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags)
1555 {
1556         char *p = buf;
1557         if (flags & LM_FLAG_TRY)
1558                 *p++ = 't';
1559         if (flags & LM_FLAG_TRY_1CB)
1560                 *p++ = 'T';
1561         if (flags & LM_FLAG_NOEXP)
1562                 *p++ = 'e';
1563         if (flags & LM_FLAG_ANY)
1564                 *p++ = 'A';
1565         if (flags & LM_FLAG_PRIORITY)
1566                 *p++ = 'p';
1567         if (flags & GL_ASYNC)
1568                 *p++ = 'a';
1569         if (flags & GL_EXACT)
1570                 *p++ = 'E';
1571         if (flags & GL_NOCACHE)
1572                 *p++ = 'c';
1573         if (test_bit(HIF_HOLDER, &iflags))
1574                 *p++ = 'H';
1575         if (test_bit(HIF_WAIT, &iflags))
1576                 *p++ = 'W';
1577         if (test_bit(HIF_FIRST, &iflags))
1578                 *p++ = 'F';
1579         *p = 0;
1580         return buf;
1581 }
1582
1583 /**
1584  * dump_holder - print information about a glock holder
1585  * @seq: the seq_file struct
1586  * @gh: the glock holder
1587  *
1588  */
1589
1590 static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1591 {
1592         struct task_struct *gh_owner = NULL;
1593         char flags_buf[32];
1594
1595         rcu_read_lock();
1596         if (gh->gh_owner_pid)
1597                 gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1598         gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1599                        state2str(gh->gh_state),
1600                        hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1601                        gh->gh_error,
1602                        gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1603                        gh_owner ? gh_owner->comm : "(ended)",
1604                        (void *)gh->gh_ip);
1605         rcu_read_unlock();
1606 }
1607
1608 static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1609 {
1610         const unsigned long *gflags = &gl->gl_flags;
1611         char *p = buf;
1612
1613         if (test_bit(GLF_LOCK, gflags))
1614                 *p++ = 'l';
1615         if (test_bit(GLF_DEMOTE, gflags))
1616                 *p++ = 'D';
1617         if (test_bit(GLF_PENDING_DEMOTE, gflags))
1618                 *p++ = 'd';
1619         if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1620                 *p++ = 'p';
1621         if (test_bit(GLF_DIRTY, gflags))
1622                 *p++ = 'y';
1623         if (test_bit(GLF_LFLUSH, gflags))
1624                 *p++ = 'f';
1625         if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1626                 *p++ = 'i';
1627         if (test_bit(GLF_REPLY_PENDING, gflags))
1628                 *p++ = 'r';
1629         if (test_bit(GLF_INITIAL, gflags))
1630                 *p++ = 'I';
1631         if (test_bit(GLF_FROZEN, gflags))
1632                 *p++ = 'F';
1633         if (test_bit(GLF_QUEUED, gflags))
1634                 *p++ = 'q';
1635         if (test_bit(GLF_LRU, gflags))
1636                 *p++ = 'L';
1637         if (gl->gl_object)
1638                 *p++ = 'o';
1639         if (test_bit(GLF_BLOCKING, gflags))
1640                 *p++ = 'b';
1641         *p = 0;
1642         return buf;
1643 }
1644
1645 /**
1646  * gfs2_dump_glock - print information about a glock
1647  * @seq: The seq_file struct
1648  * @gl: the glock
1649  *
1650  * The file format is as follows:
1651  * One line per object, capital letters are used to indicate objects
1652  * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1653  * other objects are indented by a single space and follow the glock to
1654  * which they are related. Fields are indicated by lower case letters
1655  * followed by a colon and the field value, except for strings which are in
1656  * [] so that its possible to see if they are composed of spaces for
1657  * example. The field's are n = number (id of the object), f = flags,
1658  * t = type, s = state, r = refcount, e = error, p = pid.
1659  *
1660  */
1661
1662 void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1663 {
1664         const struct gfs2_glock_operations *glops = gl->gl_ops;
1665         unsigned long long dtime;
1666         const struct gfs2_holder *gh;
1667         char gflags_buf[32];
1668
1669         dtime = jiffies - gl->gl_demote_time;
1670         dtime *= 1000000/HZ; /* demote time in uSec */
1671         if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1672                 dtime = 0;
1673         gfs2_print_dbg(seq, "G:  s:%s n:%u/%llx f:%s t:%s d:%s/%llu a:%d v:%d r:%d m:%ld\n",
1674                   state2str(gl->gl_state),
1675                   gl->gl_name.ln_type,
1676                   (unsigned long long)gl->gl_name.ln_number,
1677                   gflags2str(gflags_buf, gl),
1678                   state2str(gl->gl_target),
1679                   state2str(gl->gl_demote_state), dtime,
1680                   atomic_read(&gl->gl_ail_count),
1681                   atomic_read(&gl->gl_revokes),
1682                   (int)gl->gl_lockref.count, gl->gl_hold_time);
1683
1684         list_for_each_entry(gh, &gl->gl_holders, gh_list)
1685                 dump_holder(seq, gh);
1686
1687         if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1688                 glops->go_dump(seq, gl);
1689 }
1690
1691 static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1692 {
1693         struct gfs2_glock *gl = iter_ptr;
1694
1695         seq_printf(seq, "G: n:%u/%llx rtt:%llu/%llu rttb:%llu/%llu irt:%llu/%llu dcnt: %llu qcnt: %llu\n",
1696                    gl->gl_name.ln_type,
1697                    (unsigned long long)gl->gl_name.ln_number,
1698                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1699                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1700                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1701                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1702                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1703                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1704                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1705                    (unsigned long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1706         return 0;
1707 }
1708
1709 static const char *gfs2_gltype[] = {
1710         "type",
1711         "reserved",
1712         "nondisk",
1713         "inode",
1714         "rgrp",
1715         "meta",
1716         "iopen",
1717         "flock",
1718         "plock",
1719         "quota",
1720         "journal",
1721 };
1722
1723 static const char *gfs2_stype[] = {
1724         [GFS2_LKS_SRTT]         = "srtt",
1725         [GFS2_LKS_SRTTVAR]      = "srttvar",
1726         [GFS2_LKS_SRTTB]        = "srttb",
1727         [GFS2_LKS_SRTTVARB]     = "srttvarb",
1728         [GFS2_LKS_SIRT]         = "sirt",
1729         [GFS2_LKS_SIRTVAR]      = "sirtvar",
1730         [GFS2_LKS_DCOUNT]       = "dlm",
1731         [GFS2_LKS_QCOUNT]       = "queue",
1732 };
1733
1734 #define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1735
1736 static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1737 {
1738         struct gfs2_sbd *sdp = seq->private;
1739         loff_t pos = *(loff_t *)iter_ptr;
1740         unsigned index = pos >> 3;
1741         unsigned subindex = pos & 0x07;
1742         int i;
1743
1744         if (index == 0 && subindex != 0)
1745                 return 0;
1746
1747         seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1748                    (index == 0) ? "cpu": gfs2_stype[subindex]);
1749
1750         for_each_possible_cpu(i) {
1751                 const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1752
1753                 if (index == 0)
1754                         seq_printf(seq, " %15u", i);
1755                 else
1756                         seq_printf(seq, " %15llu", (unsigned long long)lkstats->
1757                                    lkstats[index - 1].stats[subindex]);
1758         }
1759         seq_putc(seq, '\n');
1760         return 0;
1761 }
1762
1763 int __init gfs2_glock_init(void)
1764 {
1765         int ret;
1766
1767         ret = rhashtable_init(&gl_hash_table, &ht_parms);
1768         if (ret < 0)
1769                 return ret;
1770
1771         glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1772                                           WQ_HIGHPRI | WQ_FREEZABLE, 0);
1773         if (!glock_workqueue) {
1774                 rhashtable_destroy(&gl_hash_table);
1775                 return -ENOMEM;
1776         }
1777         gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1778                                                 WQ_MEM_RECLAIM | WQ_FREEZABLE,
1779                                                 0);
1780         if (!gfs2_delete_workqueue) {
1781                 destroy_workqueue(glock_workqueue);
1782                 rhashtable_destroy(&gl_hash_table);
1783                 return -ENOMEM;
1784         }
1785
1786         register_shrinker(&glock_shrinker);
1787
1788         return 0;
1789 }
1790
1791 void gfs2_glock_exit(void)
1792 {
1793         unregister_shrinker(&glock_shrinker);
1794         rhashtable_destroy(&gl_hash_table);
1795         destroy_workqueue(glock_workqueue);
1796         destroy_workqueue(gfs2_delete_workqueue);
1797 }
1798
1799 static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1800 {
1801         do {
1802                 gi->gl = rhashtable_walk_next(&gi->hti);
1803                 if (IS_ERR(gi->gl)) {
1804                         if (PTR_ERR(gi->gl) == -EAGAIN)
1805                                 continue;
1806                         gi->gl = NULL;
1807                 }
1808         /* Skip entries for other sb and dead entries */
1809         } while ((gi->gl) && ((gi->sdp != gi->gl->gl_name.ln_sbd) ||
1810                               __lockref_is_dead(&gi->gl->gl_lockref)));
1811 }
1812
1813 static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1814 {
1815         struct gfs2_glock_iter *gi = seq->private;
1816         loff_t n = *pos;
1817         int ret;
1818
1819         if (gi->last_pos <= *pos)
1820                 n = (*pos - gi->last_pos);
1821
1822         ret = rhashtable_walk_start(&gi->hti);
1823         if (ret)
1824                 return NULL;
1825
1826         do {
1827                 gfs2_glock_iter_next(gi);
1828         } while (gi->gl && n--);
1829
1830         gi->last_pos = *pos;
1831         return gi->gl;
1832 }
1833
1834 static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1835                                  loff_t *pos)
1836 {
1837         struct gfs2_glock_iter *gi = seq->private;
1838
1839         (*pos)++;
1840         gi->last_pos = *pos;
1841         gfs2_glock_iter_next(gi);
1842         return gi->gl;
1843 }
1844
1845 static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1846 {
1847         struct gfs2_glock_iter *gi = seq->private;
1848
1849         gi->gl = NULL;
1850         rhashtable_walk_stop(&gi->hti);
1851 }
1852
1853 static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1854 {
1855         dump_glock(seq, iter_ptr);
1856         return 0;
1857 }
1858
1859 static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
1860 {
1861         preempt_disable();
1862         if (*pos >= GFS2_NR_SBSTATS)
1863                 return NULL;
1864         return pos;
1865 }
1866
1867 static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
1868                                    loff_t *pos)
1869 {
1870         (*pos)++;
1871         if (*pos >= GFS2_NR_SBSTATS)
1872                 return NULL;
1873         return pos;
1874 }
1875
1876 static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
1877 {
1878         preempt_enable();
1879 }
1880
1881 static const struct seq_operations gfs2_glock_seq_ops = {
1882         .start = gfs2_glock_seq_start,
1883         .next  = gfs2_glock_seq_next,
1884         .stop  = gfs2_glock_seq_stop,
1885         .show  = gfs2_glock_seq_show,
1886 };
1887
1888 static const struct seq_operations gfs2_glstats_seq_ops = {
1889         .start = gfs2_glock_seq_start,
1890         .next  = gfs2_glock_seq_next,
1891         .stop  = gfs2_glock_seq_stop,
1892         .show  = gfs2_glstats_seq_show,
1893 };
1894
1895 static const struct seq_operations gfs2_sbstats_seq_ops = {
1896         .start = gfs2_sbstats_seq_start,
1897         .next  = gfs2_sbstats_seq_next,
1898         .stop  = gfs2_sbstats_seq_stop,
1899         .show  = gfs2_sbstats_seq_show,
1900 };
1901
1902 #define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
1903
1904 static int gfs2_glocks_open(struct inode *inode, struct file *file)
1905 {
1906         int ret = seq_open_private(file, &gfs2_glock_seq_ops,
1907                                    sizeof(struct gfs2_glock_iter));
1908         if (ret == 0) {
1909                 struct seq_file *seq = file->private_data;
1910                 struct gfs2_glock_iter *gi = seq->private;
1911
1912                 gi->sdp = inode->i_private;
1913                 gi->last_pos = 0;
1914                 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
1915                 if (seq->buf)
1916                         seq->size = GFS2_SEQ_GOODSIZE;
1917                 gi->gl = NULL;
1918                 ret = rhashtable_walk_init(&gl_hash_table, &gi->hti);
1919         }
1920         return ret;
1921 }
1922
1923 static int gfs2_glocks_release(struct inode *inode, struct file *file)
1924 {
1925         struct seq_file *seq = file->private_data;
1926         struct gfs2_glock_iter *gi = seq->private;
1927
1928         gi->gl = NULL;
1929         rhashtable_walk_exit(&gi->hti);
1930         return seq_release_private(inode, file);
1931 }
1932
1933 static int gfs2_glstats_open(struct inode *inode, struct file *file)
1934 {
1935         int ret = seq_open_private(file, &gfs2_glstats_seq_ops,
1936                                    sizeof(struct gfs2_glock_iter));
1937         if (ret == 0) {
1938                 struct seq_file *seq = file->private_data;
1939                 struct gfs2_glock_iter *gi = seq->private;
1940                 gi->sdp = inode->i_private;
1941                 gi->last_pos = 0;
1942                 seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
1943                 if (seq->buf)
1944                         seq->size = GFS2_SEQ_GOODSIZE;
1945                 gi->gl = NULL;
1946                 ret = rhashtable_walk_init(&gl_hash_table, &gi->hti);
1947         }
1948         return ret;
1949 }
1950
1951 static int gfs2_sbstats_open(struct inode *inode, struct file *file)
1952 {
1953         int ret = seq_open(file, &gfs2_sbstats_seq_ops);
1954         if (ret == 0) {
1955                 struct seq_file *seq = file->private_data;
1956                 seq->private = inode->i_private;  /* sdp */
1957         }
1958         return ret;
1959 }
1960
1961 static const struct file_operations gfs2_glocks_fops = {
1962         .owner   = THIS_MODULE,
1963         .open    = gfs2_glocks_open,
1964         .read    = seq_read,
1965         .llseek  = seq_lseek,
1966         .release = gfs2_glocks_release,
1967 };
1968
1969 static const struct file_operations gfs2_glstats_fops = {
1970         .owner   = THIS_MODULE,
1971         .open    = gfs2_glstats_open,
1972         .read    = seq_read,
1973         .llseek  = seq_lseek,
1974         .release = gfs2_glocks_release,
1975 };
1976
1977 static const struct file_operations gfs2_sbstats_fops = {
1978         .owner   = THIS_MODULE,
1979         .open    = gfs2_sbstats_open,
1980         .read    = seq_read,
1981         .llseek  = seq_lseek,
1982         .release = seq_release,
1983 };
1984
1985 int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
1986 {
1987         struct dentry *dent;
1988
1989         dent = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
1990         if (IS_ERR_OR_NULL(dent))
1991                 goto fail;
1992         sdp->debugfs_dir = dent;
1993
1994         dent = debugfs_create_file("glocks",
1995                                    S_IFREG | S_IRUGO,
1996                                    sdp->debugfs_dir, sdp,
1997                                    &gfs2_glocks_fops);
1998         if (IS_ERR_OR_NULL(dent))
1999                 goto fail;
2000         sdp->debugfs_dentry_glocks = dent;
2001
2002         dent = debugfs_create_file("glstats",
2003                                    S_IFREG | S_IRUGO,
2004                                    sdp->debugfs_dir, sdp,
2005                                    &gfs2_glstats_fops);
2006         if (IS_ERR_OR_NULL(dent))
2007                 goto fail;
2008         sdp->debugfs_dentry_glstats = dent;
2009
2010         dent = debugfs_create_file("sbstats",
2011                                    S_IFREG | S_IRUGO,
2012                                    sdp->debugfs_dir, sdp,
2013                                    &gfs2_sbstats_fops);
2014         if (IS_ERR_OR_NULL(dent))
2015                 goto fail;
2016         sdp->debugfs_dentry_sbstats = dent;
2017
2018         return 0;
2019 fail:
2020         gfs2_delete_debugfs_file(sdp);
2021         return dent ? PTR_ERR(dent) : -ENOMEM;
2022 }
2023
2024 void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2025 {
2026         if (sdp->debugfs_dir) {
2027                 if (sdp->debugfs_dentry_glocks) {
2028                         debugfs_remove(sdp->debugfs_dentry_glocks);
2029                         sdp->debugfs_dentry_glocks = NULL;
2030                 }
2031                 if (sdp->debugfs_dentry_glstats) {
2032                         debugfs_remove(sdp->debugfs_dentry_glstats);
2033                         sdp->debugfs_dentry_glstats = NULL;
2034                 }
2035                 if (sdp->debugfs_dentry_sbstats) {
2036                         debugfs_remove(sdp->debugfs_dentry_sbstats);
2037                         sdp->debugfs_dentry_sbstats = NULL;
2038                 }
2039                 debugfs_remove(sdp->debugfs_dir);
2040                 sdp->debugfs_dir = NULL;
2041         }
2042 }
2043
2044 int gfs2_register_debugfs(void)
2045 {
2046         gfs2_root = debugfs_create_dir("gfs2", NULL);
2047         if (IS_ERR(gfs2_root))
2048                 return PTR_ERR(gfs2_root);
2049         return gfs2_root ? 0 : -ENOMEM;
2050 }
2051
2052 void gfs2_unregister_debugfs(void)
2053 {
2054         debugfs_remove(gfs2_root);
2055         gfs2_root = NULL;
2056 }