linux/fs/gfs2/glock.c
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   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/hash.h>
  19#include <linux/jhash.h>
  20#include <linux/kallsyms.h>
  21#include <linux/gfs2_ondisk.h>
  22#include <linux/list.h>
  23#include <linux/wait.h>
  24#include <linux/module.h>
  25#include <linux/uaccess.h>
  26#include <linux/seq_file.h>
  27#include <linux/debugfs.h>
  28#include <linux/kthread.h>
  29#include <linux/freezer.h>
  30#include <linux/workqueue.h>
  31#include <linux/jiffies.h>
  32#include <linux/rcupdate.h>
  33#include <linux/rculist_bl.h>
  34#include <linux/bit_spinlock.h>
  35#include <linux/percpu.h>
  36#include <linux/list_sort.h>
  37#include <linux/lockref.h>
  38#include <linux/rhashtable.h>
  39
  40#include "gfs2.h"
  41#include "incore.h"
  42#include "glock.h"
  43#include "glops.h"
  44#include "inode.h"
  45#include "lops.h"
  46#include "meta_io.h"
  47#include "quota.h"
  48#include "super.h"
  49#include "util.h"
  50#include "bmap.h"
  51#define CREATE_TRACE_POINTS
  52#include "trace_gfs2.h"
  53
  54struct gfs2_glock_iter {
  55        struct gfs2_sbd *sdp;           /* incore superblock           */
  56        struct rhashtable_iter hti;     /* rhashtable iterator         */
  57        struct gfs2_glock *gl;          /* current glock struct        */
  58        loff_t last_pos;                /* last position               */
  59};
  60
  61typedef void (*glock_examiner) (struct gfs2_glock * gl);
  62
  63static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
  64
  65static struct dentry *gfs2_root;
  66static struct workqueue_struct *glock_workqueue;
  67struct workqueue_struct *gfs2_delete_workqueue;
  68static LIST_HEAD(lru_list);
  69static atomic_t lru_count = ATOMIC_INIT(0);
  70static DEFINE_SPINLOCK(lru_lock);
  71
  72#define GFS2_GL_HASH_SHIFT      15
  73#define GFS2_GL_HASH_SIZE       BIT(GFS2_GL_HASH_SHIFT)
  74
  75static const struct rhashtable_params ht_parms = {
  76        .nelem_hint = GFS2_GL_HASH_SIZE * 3 / 4,
  77        .key_len = offsetofend(struct lm_lockname, ln_type),
  78        .key_offset = offsetof(struct gfs2_glock, gl_name),
  79        .head_offset = offsetof(struct gfs2_glock, gl_node),
  80};
  81
  82static struct rhashtable gl_hash_table;
  83
  84#define GLOCK_WAIT_TABLE_BITS 12
  85#define GLOCK_WAIT_TABLE_SIZE (1 << GLOCK_WAIT_TABLE_BITS)
  86static wait_queue_head_t glock_wait_table[GLOCK_WAIT_TABLE_SIZE] __cacheline_aligned;
  87
  88struct wait_glock_queue {
  89        struct lm_lockname *name;
  90        wait_queue_entry_t wait;
  91};
  92
  93static int glock_wake_function(wait_queue_entry_t *wait, unsigned int mode,
  94                               int sync, void *key)
  95{
  96        struct wait_glock_queue *wait_glock =
  97                container_of(wait, struct wait_glock_queue, wait);
  98        struct lm_lockname *wait_name = wait_glock->name;
  99        struct lm_lockname *wake_name = key;
 100
 101        if (wake_name->ln_sbd != wait_name->ln_sbd ||
 102            wake_name->ln_number != wait_name->ln_number ||
 103            wake_name->ln_type != wait_name->ln_type)
 104                return 0;
 105        return autoremove_wake_function(wait, mode, sync, key);
 106}
 107
 108static wait_queue_head_t *glock_waitqueue(struct lm_lockname *name)
 109{
 110        u32 hash = jhash2((u32 *)name, sizeof(*name) / 4, 0);
 111
 112        return glock_wait_table + hash_32(hash, GLOCK_WAIT_TABLE_BITS);
 113}
 114
 115/**
 116 * wake_up_glock  -  Wake up waiters on a glock
 117 * @gl: the glock
 118 */
 119static void wake_up_glock(struct gfs2_glock *gl)
 120{
 121        wait_queue_head_t *wq = glock_waitqueue(&gl->gl_name);
 122
 123        if (waitqueue_active(wq))
 124                __wake_up(wq, TASK_NORMAL, 1, &gl->gl_name);
 125}
 126
 127static void gfs2_glock_dealloc(struct rcu_head *rcu)
 128{
 129        struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
 130
 131        if (gl->gl_ops->go_flags & GLOF_ASPACE) {
 132                kmem_cache_free(gfs2_glock_aspace_cachep, gl);
 133        } else {
 134                kfree(gl->gl_lksb.sb_lvbptr);
 135                kmem_cache_free(gfs2_glock_cachep, gl);
 136        }
 137}
 138
 139void gfs2_glock_free(struct gfs2_glock *gl)
 140{
 141        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 142
 143        rhashtable_remove_fast(&gl_hash_table, &gl->gl_node, ht_parms);
 144        smp_mb();
 145        wake_up_glock(gl);
 146        call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
 147        if (atomic_dec_and_test(&sdp->sd_glock_disposal))
 148                wake_up(&sdp->sd_glock_wait);
 149}
 150
 151/**
 152 * gfs2_glock_hold() - increment reference count on glock
 153 * @gl: The glock to hold
 154 *
 155 */
 156
 157void gfs2_glock_hold(struct gfs2_glock *gl)
 158{
 159        GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
 160        lockref_get(&gl->gl_lockref);
 161}
 162
 163/**
 164 * demote_ok - Check to see if it's ok to unlock a glock
 165 * @gl: the glock
 166 *
 167 * Returns: 1 if it's ok
 168 */
 169
 170static int demote_ok(const struct gfs2_glock *gl)
 171{
 172        const struct gfs2_glock_operations *glops = gl->gl_ops;
 173
 174        if (gl->gl_state == LM_ST_UNLOCKED)
 175                return 0;
 176        if (!list_empty(&gl->gl_holders))
 177                return 0;
 178        if (glops->go_demote_ok)
 179                return glops->go_demote_ok(gl);
 180        return 1;
 181}
 182
 183
 184void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
 185{
 186        spin_lock(&lru_lock);
 187
 188        if (!list_empty(&gl->gl_lru))
 189                list_del_init(&gl->gl_lru);
 190        else
 191                atomic_inc(&lru_count);
 192
 193        list_add_tail(&gl->gl_lru, &lru_list);
 194        set_bit(GLF_LRU, &gl->gl_flags);
 195        spin_unlock(&lru_lock);
 196}
 197
 198static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
 199{
 200        if (!(gl->gl_ops->go_flags & GLOF_LRU))
 201                return;
 202
 203        spin_lock(&lru_lock);
 204        if (!list_empty(&gl->gl_lru)) {
 205                list_del_init(&gl->gl_lru);
 206                atomic_dec(&lru_count);
 207                clear_bit(GLF_LRU, &gl->gl_flags);
 208        }
 209        spin_unlock(&lru_lock);
 210}
 211
 212/*
 213 * Enqueue the glock on the work queue.  Passes one glock reference on to the
 214 * work queue.
 215 */
 216static void __gfs2_glock_queue_work(struct gfs2_glock *gl, unsigned long delay) {
 217        if (!queue_delayed_work(glock_workqueue, &gl->gl_work, delay)) {
 218                /*
 219                 * We are holding the lockref spinlock, and the work was still
 220                 * queued above.  The queued work (glock_work_func) takes that
 221                 * spinlock before dropping its glock reference(s), so it
 222                 * cannot have dropped them in the meantime.
 223                 */
 224                GLOCK_BUG_ON(gl, gl->gl_lockref.count < 2);
 225                gl->gl_lockref.count--;
 226        }
 227}
 228
 229static void gfs2_glock_queue_work(struct gfs2_glock *gl, unsigned long delay) {
 230        spin_lock(&gl->gl_lockref.lock);
 231        __gfs2_glock_queue_work(gl, delay);
 232        spin_unlock(&gl->gl_lockref.lock);
 233}
 234
 235static void __gfs2_glock_put(struct gfs2_glock *gl)
 236{
 237        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 238        struct address_space *mapping = gfs2_glock2aspace(gl);
 239
 240        lockref_mark_dead(&gl->gl_lockref);
 241
 242        gfs2_glock_remove_from_lru(gl);
 243        spin_unlock(&gl->gl_lockref.lock);
 244        GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
 245        GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
 246        trace_gfs2_glock_put(gl);
 247        sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
 248}
 249
 250/*
 251 * Cause the glock to be put in work queue context.
 252 */
 253void gfs2_glock_queue_put(struct gfs2_glock *gl)
 254{
 255        gfs2_glock_queue_work(gl, 0);
 256}
 257
 258/**
 259 * gfs2_glock_put() - Decrement reference count on glock
 260 * @gl: The glock to put
 261 *
 262 */
 263
 264void gfs2_glock_put(struct gfs2_glock *gl)
 265{
 266        if (lockref_put_or_lock(&gl->gl_lockref))
 267                return;
 268
 269        __gfs2_glock_put(gl);
 270}
 271
 272/**
 273 * may_grant - check if its ok to grant a new lock
 274 * @gl: The glock
 275 * @gh: The lock request which we wish to grant
 276 *
 277 * Returns: true if its ok to grant the lock
 278 */
 279
 280static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
 281{
 282        const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
 283        if ((gh->gh_state == LM_ST_EXCLUSIVE ||
 284             gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
 285                return 0;
 286        if (gl->gl_state == gh->gh_state)
 287                return 1;
 288        if (gh->gh_flags & GL_EXACT)
 289                return 0;
 290        if (gl->gl_state == LM_ST_EXCLUSIVE) {
 291                if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
 292                        return 1;
 293                if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
 294                        return 1;
 295        }
 296        if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
 297                return 1;
 298        return 0;
 299}
 300
 301static void gfs2_holder_wake(struct gfs2_holder *gh)
 302{
 303        clear_bit(HIF_WAIT, &gh->gh_iflags);
 304        smp_mb__after_atomic();
 305        wake_up_bit(&gh->gh_iflags, HIF_WAIT);
 306}
 307
 308/**
 309 * do_error - Something unexpected has happened during a lock request
 310 *
 311 */
 312
 313static void do_error(struct gfs2_glock *gl, const int ret)
 314{
 315        struct gfs2_holder *gh, *tmp;
 316
 317        list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
 318                if (test_bit(HIF_HOLDER, &gh->gh_iflags))
 319                        continue;
 320                if (ret & LM_OUT_ERROR)
 321                        gh->gh_error = -EIO;
 322                else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
 323                        gh->gh_error = GLR_TRYFAILED;
 324                else
 325                        continue;
 326                list_del_init(&gh->gh_list);
 327                trace_gfs2_glock_queue(gh, 0);
 328                gfs2_holder_wake(gh);
 329        }
 330}
 331
 332/**
 333 * do_promote - promote as many requests as possible on the current queue
 334 * @gl: The glock
 335 * 
 336 * Returns: 1 if there is a blocked holder at the head of the list, or 2
 337 *          if a type specific operation is underway.
 338 */
 339
 340static int do_promote(struct gfs2_glock *gl)
 341__releases(&gl->gl_lockref.lock)
 342__acquires(&gl->gl_lockref.lock)
 343{
 344        const struct gfs2_glock_operations *glops = gl->gl_ops;
 345        struct gfs2_holder *gh, *tmp;
 346        int ret;
 347
 348restart:
 349        list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
 350                if (test_bit(HIF_HOLDER, &gh->gh_iflags))
 351                        continue;
 352                if (may_grant(gl, gh)) {
 353                        if (gh->gh_list.prev == &gl->gl_holders &&
 354                            glops->go_lock) {
 355                                spin_unlock(&gl->gl_lockref.lock);
 356                                /* FIXME: eliminate this eventually */
 357                                ret = glops->go_lock(gh);
 358                                spin_lock(&gl->gl_lockref.lock);
 359                                if (ret) {
 360                                        if (ret == 1)
 361                                                return 2;
 362                                        gh->gh_error = ret;
 363                                        list_del_init(&gh->gh_list);
 364                                        trace_gfs2_glock_queue(gh, 0);
 365                                        gfs2_holder_wake(gh);
 366                                        goto restart;
 367                                }
 368                                set_bit(HIF_HOLDER, &gh->gh_iflags);
 369                                trace_gfs2_promote(gh, 1);
 370                                gfs2_holder_wake(gh);
 371                                goto restart;
 372                        }
 373                        set_bit(HIF_HOLDER, &gh->gh_iflags);
 374                        trace_gfs2_promote(gh, 0);
 375                        gfs2_holder_wake(gh);
 376                        continue;
 377                }
 378                if (gh->gh_list.prev == &gl->gl_holders)
 379                        return 1;
 380                do_error(gl, 0);
 381                break;
 382        }
 383        return 0;
 384}
 385
 386/**
 387 * find_first_waiter - find the first gh that's waiting for the glock
 388 * @gl: the glock
 389 */
 390
 391static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
 392{
 393        struct gfs2_holder *gh;
 394
 395        list_for_each_entry(gh, &gl->gl_holders, gh_list) {
 396                if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
 397                        return gh;
 398        }
 399        return NULL;
 400}
 401
 402/**
 403 * state_change - record that the glock is now in a different state
 404 * @gl: the glock
 405 * @new_state the new state
 406 *
 407 */
 408
 409static void state_change(struct gfs2_glock *gl, unsigned int new_state)
 410{
 411        int held1, held2;
 412
 413        held1 = (gl->gl_state != LM_ST_UNLOCKED);
 414        held2 = (new_state != LM_ST_UNLOCKED);
 415
 416        if (held1 != held2) {
 417                GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
 418                if (held2)
 419                        gl->gl_lockref.count++;
 420                else
 421                        gl->gl_lockref.count--;
 422        }
 423        if (held1 && held2 && list_empty(&gl->gl_holders))
 424                clear_bit(GLF_QUEUED, &gl->gl_flags);
 425
 426        if (new_state != gl->gl_target)
 427                /* shorten our minimum hold time */
 428                gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
 429                                       GL_GLOCK_MIN_HOLD);
 430        gl->gl_state = new_state;
 431        gl->gl_tchange = jiffies;
 432}
 433
 434static void gfs2_demote_wake(struct gfs2_glock *gl)
 435{
 436        gl->gl_demote_state = LM_ST_EXCLUSIVE;
 437        clear_bit(GLF_DEMOTE, &gl->gl_flags);
 438        smp_mb__after_atomic();
 439        wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
 440}
 441
 442/**
 443 * finish_xmote - The DLM has replied to one of our lock requests
 444 * @gl: The glock
 445 * @ret: The status from the DLM
 446 *
 447 */
 448
 449static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
 450{
 451        const struct gfs2_glock_operations *glops = gl->gl_ops;
 452        struct gfs2_holder *gh;
 453        unsigned state = ret & LM_OUT_ST_MASK;
 454        int rv;
 455
 456        spin_lock(&gl->gl_lockref.lock);
 457        trace_gfs2_glock_state_change(gl, state);
 458        state_change(gl, state);
 459        gh = find_first_waiter(gl);
 460
 461        /* Demote to UN request arrived during demote to SH or DF */
 462        if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
 463            state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
 464                gl->gl_target = LM_ST_UNLOCKED;
 465
 466        /* Check for state != intended state */
 467        if (unlikely(state != gl->gl_target)) {
 468                if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
 469                        /* move to back of queue and try next entry */
 470                        if (ret & LM_OUT_CANCELED) {
 471                                if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
 472                                        list_move_tail(&gh->gh_list, &gl->gl_holders);
 473                                gh = find_first_waiter(gl);
 474                                gl->gl_target = gh->gh_state;
 475                                goto retry;
 476                        }
 477                        /* Some error or failed "try lock" - report it */
 478                        if ((ret & LM_OUT_ERROR) ||
 479                            (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
 480                                gl->gl_target = gl->gl_state;
 481                                do_error(gl, ret);
 482                                goto out;
 483                        }
 484                }
 485                switch(state) {
 486                /* Unlocked due to conversion deadlock, try again */
 487                case LM_ST_UNLOCKED:
 488retry:
 489                        do_xmote(gl, gh, gl->gl_target);
 490                        break;
 491                /* Conversion fails, unlock and try again */
 492                case LM_ST_SHARED:
 493                case LM_ST_DEFERRED:
 494                        do_xmote(gl, gh, LM_ST_UNLOCKED);
 495                        break;
 496                default: /* Everything else */
 497                        pr_err("wanted %u got %u\n", gl->gl_target, state);
 498                        GLOCK_BUG_ON(gl, 1);
 499                }
 500                spin_unlock(&gl->gl_lockref.lock);
 501                return;
 502        }
 503
 504        /* Fast path - we got what we asked for */
 505        if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
 506                gfs2_demote_wake(gl);
 507        if (state != LM_ST_UNLOCKED) {
 508                if (glops->go_xmote_bh) {
 509                        spin_unlock(&gl->gl_lockref.lock);
 510                        rv = glops->go_xmote_bh(gl, gh);
 511                        spin_lock(&gl->gl_lockref.lock);
 512                        if (rv) {
 513                                do_error(gl, rv);
 514                                goto out;
 515                        }
 516                }
 517                rv = do_promote(gl);
 518                if (rv == 2)
 519                        goto out_locked;
 520        }
 521out:
 522        clear_bit(GLF_LOCK, &gl->gl_flags);
 523out_locked:
 524        spin_unlock(&gl->gl_lockref.lock);
 525}
 526
 527/**
 528 * do_xmote - Calls the DLM to change the state of a lock
 529 * @gl: The lock state
 530 * @gh: The holder (only for promotes)
 531 * @target: The target lock state
 532 *
 533 */
 534
 535static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
 536__releases(&gl->gl_lockref.lock)
 537__acquires(&gl->gl_lockref.lock)
 538{
 539        const struct gfs2_glock_operations *glops = gl->gl_ops;
 540        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 541        unsigned int lck_flags = (unsigned int)(gh ? gh->gh_flags : 0);
 542        int ret;
 543
 544        if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)) &&
 545            target != LM_ST_UNLOCKED)
 546                return;
 547        lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
 548                      LM_FLAG_PRIORITY);
 549        GLOCK_BUG_ON(gl, gl->gl_state == target);
 550        GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
 551        if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
 552            glops->go_inval) {
 553                set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
 554                do_error(gl, 0); /* Fail queued try locks */
 555        }
 556        gl->gl_req = target;
 557        set_bit(GLF_BLOCKING, &gl->gl_flags);
 558        if ((gl->gl_req == LM_ST_UNLOCKED) ||
 559            (gl->gl_state == LM_ST_EXCLUSIVE) ||
 560            (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
 561                clear_bit(GLF_BLOCKING, &gl->gl_flags);
 562        spin_unlock(&gl->gl_lockref.lock);
 563        if (glops->go_sync)
 564                glops->go_sync(gl);
 565        if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
 566                glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
 567        clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
 568
 569        gfs2_glock_hold(gl);
 570        if (sdp->sd_lockstruct.ls_ops->lm_lock) {
 571                /* lock_dlm */
 572                ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
 573                if (ret == -EINVAL && gl->gl_target == LM_ST_UNLOCKED &&
 574                    target == LM_ST_UNLOCKED &&
 575                    test_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags)) {
 576                        finish_xmote(gl, target);
 577                        gfs2_glock_queue_work(gl, 0);
 578                }
 579                else if (ret) {
 580                        pr_err("lm_lock ret %d\n", ret);
 581                        GLOCK_BUG_ON(gl, !test_bit(SDF_SHUTDOWN,
 582                                                   &sdp->sd_flags));
 583                }
 584        } else { /* lock_nolock */
 585                finish_xmote(gl, target);
 586                gfs2_glock_queue_work(gl, 0);
 587        }
 588
 589        spin_lock(&gl->gl_lockref.lock);
 590}
 591
 592/**
 593 * find_first_holder - find the first "holder" gh
 594 * @gl: the glock
 595 */
 596
 597static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
 598{
 599        struct gfs2_holder *gh;
 600
 601        if (!list_empty(&gl->gl_holders)) {
 602                gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
 603                if (test_bit(HIF_HOLDER, &gh->gh_iflags))
 604                        return gh;
 605        }
 606        return NULL;
 607}
 608
 609/**
 610 * run_queue - do all outstanding tasks related to a glock
 611 * @gl: The glock in question
 612 * @nonblock: True if we must not block in run_queue
 613 *
 614 */
 615
 616static void run_queue(struct gfs2_glock *gl, const int nonblock)
 617__releases(&gl->gl_lockref.lock)
 618__acquires(&gl->gl_lockref.lock)
 619{
 620        struct gfs2_holder *gh = NULL;
 621        int ret;
 622
 623        if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
 624                return;
 625
 626        GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
 627
 628        if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
 629            gl->gl_demote_state != gl->gl_state) {
 630                if (find_first_holder(gl))
 631                        goto out_unlock;
 632                if (nonblock)
 633                        goto out_sched;
 634                set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
 635                GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
 636                gl->gl_target = gl->gl_demote_state;
 637        } else {
 638                if (test_bit(GLF_DEMOTE, &gl->gl_flags))
 639                        gfs2_demote_wake(gl);
 640                ret = do_promote(gl);
 641                if (ret == 0)
 642                        goto out_unlock;
 643                if (ret == 2)
 644                        goto out;
 645                gh = find_first_waiter(gl);
 646                gl->gl_target = gh->gh_state;
 647                if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
 648                        do_error(gl, 0); /* Fail queued try locks */
 649        }
 650        do_xmote(gl, gh, gl->gl_target);
 651out:
 652        return;
 653
 654out_sched:
 655        clear_bit(GLF_LOCK, &gl->gl_flags);
 656        smp_mb__after_atomic();
 657        gl->gl_lockref.count++;
 658        __gfs2_glock_queue_work(gl, 0);
 659        return;
 660
 661out_unlock:
 662        clear_bit(GLF_LOCK, &gl->gl_flags);
 663        smp_mb__after_atomic();
 664        return;
 665}
 666
 667static void delete_work_func(struct work_struct *work)
 668{
 669        struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
 670        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 671        struct inode *inode;
 672        u64 no_addr = gl->gl_name.ln_number;
 673
 674        /* If someone's using this glock to create a new dinode, the block must
 675           have been freed by another node, then re-used, in which case our
 676           iopen callback is too late after the fact. Ignore it. */
 677        if (test_bit(GLF_INODE_CREATING, &gl->gl_flags))
 678                goto out;
 679
 680        inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
 681        if (inode && !IS_ERR(inode)) {
 682                d_prune_aliases(inode);
 683                iput(inode);
 684        }
 685out:
 686        gfs2_glock_put(gl);
 687}
 688
 689static void glock_work_func(struct work_struct *work)
 690{
 691        unsigned long delay = 0;
 692        struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
 693        unsigned int drop_refs = 1;
 694
 695        if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
 696                finish_xmote(gl, gl->gl_reply);
 697                drop_refs++;
 698        }
 699        spin_lock(&gl->gl_lockref.lock);
 700        if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
 701            gl->gl_state != LM_ST_UNLOCKED &&
 702            gl->gl_demote_state != LM_ST_EXCLUSIVE) {
 703                unsigned long holdtime, now = jiffies;
 704
 705                holdtime = gl->gl_tchange + gl->gl_hold_time;
 706                if (time_before(now, holdtime))
 707                        delay = holdtime - now;
 708
 709                if (!delay) {
 710                        clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
 711                        set_bit(GLF_DEMOTE, &gl->gl_flags);
 712                }
 713        }
 714        run_queue(gl, 0);
 715        if (delay) {
 716                /* Keep one glock reference for the work we requeue. */
 717                drop_refs--;
 718                if (gl->gl_name.ln_type != LM_TYPE_INODE)
 719                        delay = 0;
 720                __gfs2_glock_queue_work(gl, delay);
 721        }
 722
 723        /*
 724         * Drop the remaining glock references manually here. (Mind that
 725         * __gfs2_glock_queue_work depends on the lockref spinlock begin held
 726         * here as well.)
 727         */
 728        gl->gl_lockref.count -= drop_refs;
 729        if (!gl->gl_lockref.count) {
 730                __gfs2_glock_put(gl);
 731                return;
 732        }
 733        spin_unlock(&gl->gl_lockref.lock);
 734}
 735
 736static struct gfs2_glock *find_insert_glock(struct lm_lockname *name,
 737                                            struct gfs2_glock *new)
 738{
 739        struct wait_glock_queue wait;
 740        wait_queue_head_t *wq = glock_waitqueue(name);
 741        struct gfs2_glock *gl;
 742
 743        wait.name = name;
 744        init_wait(&wait.wait);
 745        wait.wait.func = glock_wake_function;
 746
 747again:
 748        prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
 749        rcu_read_lock();
 750        if (new) {
 751                gl = rhashtable_lookup_get_insert_fast(&gl_hash_table,
 752                        &new->gl_node, ht_parms);
 753                if (IS_ERR(gl))
 754                        goto out;
 755        } else {
 756                gl = rhashtable_lookup_fast(&gl_hash_table,
 757                        name, ht_parms);
 758        }
 759        if (gl && !lockref_get_not_dead(&gl->gl_lockref)) {
 760                rcu_read_unlock();
 761                schedule();
 762                goto again;
 763        }
 764out:
 765        rcu_read_unlock();
 766        finish_wait(wq, &wait.wait);
 767        return gl;
 768}
 769
 770/**
 771 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
 772 * @sdp: The GFS2 superblock
 773 * @number: the lock number
 774 * @glops: The glock_operations to use
 775 * @create: If 0, don't create the glock if it doesn't exist
 776 * @glp: the glock is returned here
 777 *
 778 * This does not lock a glock, just finds/creates structures for one.
 779 *
 780 * Returns: errno
 781 */
 782
 783int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
 784                   const struct gfs2_glock_operations *glops, int create,
 785                   struct gfs2_glock **glp)
 786{
 787        struct super_block *s = sdp->sd_vfs;
 788        struct lm_lockname name = { .ln_number = number,
 789                                    .ln_type = glops->go_type,
 790                                    .ln_sbd = sdp };
 791        struct gfs2_glock *gl, *tmp;
 792        struct address_space *mapping;
 793        struct kmem_cache *cachep;
 794        int ret = 0;
 795
 796        gl = find_insert_glock(&name, NULL);
 797        if (gl) {
 798                *glp = gl;
 799                return 0;
 800        }
 801        if (!create)
 802                return -ENOENT;
 803
 804        if (glops->go_flags & GLOF_ASPACE)
 805                cachep = gfs2_glock_aspace_cachep;
 806        else
 807                cachep = gfs2_glock_cachep;
 808        gl = kmem_cache_alloc(cachep, GFP_NOFS);
 809        if (!gl)
 810                return -ENOMEM;
 811
 812        memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
 813
 814        if (glops->go_flags & GLOF_LVB) {
 815                gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_NOFS);
 816                if (!gl->gl_lksb.sb_lvbptr) {
 817                        kmem_cache_free(cachep, gl);
 818                        return -ENOMEM;
 819                }
 820        }
 821
 822        atomic_inc(&sdp->sd_glock_disposal);
 823        gl->gl_node.next = NULL;
 824        gl->gl_flags = 0;
 825        gl->gl_name = name;
 826        gl->gl_lockref.count = 1;
 827        gl->gl_state = LM_ST_UNLOCKED;
 828        gl->gl_target = LM_ST_UNLOCKED;
 829        gl->gl_demote_state = LM_ST_EXCLUSIVE;
 830        gl->gl_ops = glops;
 831        gl->gl_dstamp = 0;
 832        preempt_disable();
 833        /* We use the global stats to estimate the initial per-glock stats */
 834        gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
 835        preempt_enable();
 836        gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
 837        gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
 838        gl->gl_tchange = jiffies;
 839        gl->gl_object = NULL;
 840        gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
 841        INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
 842        INIT_WORK(&gl->gl_delete, delete_work_func);
 843
 844        mapping = gfs2_glock2aspace(gl);
 845        if (mapping) {
 846                mapping->a_ops = &gfs2_meta_aops;
 847                mapping->host = s->s_bdev->bd_inode;
 848                mapping->flags = 0;
 849                mapping_set_gfp_mask(mapping, GFP_NOFS);
 850                mapping->private_data = NULL;
 851                mapping->writeback_index = 0;
 852        }
 853
 854        tmp = find_insert_glock(&name, gl);
 855        if (!tmp) {
 856                *glp = gl;
 857                goto out;
 858        }
 859        if (IS_ERR(tmp)) {
 860                ret = PTR_ERR(tmp);
 861                goto out_free;
 862        }
 863        *glp = tmp;
 864
 865out_free:
 866        kfree(gl->gl_lksb.sb_lvbptr);
 867        kmem_cache_free(cachep, gl);
 868        atomic_dec(&sdp->sd_glock_disposal);
 869
 870out:
 871        return ret;
 872}
 873
 874/**
 875 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
 876 * @gl: the glock
 877 * @state: the state we're requesting
 878 * @flags: the modifier flags
 879 * @gh: the holder structure
 880 *
 881 */
 882
 883void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, u16 flags,
 884                      struct gfs2_holder *gh)
 885{
 886        INIT_LIST_HEAD(&gh->gh_list);
 887        gh->gh_gl = gl;
 888        gh->gh_ip = _RET_IP_;
 889        gh->gh_owner_pid = get_pid(task_pid(current));
 890        gh->gh_state = state;
 891        gh->gh_flags = flags;
 892        gh->gh_error = 0;
 893        gh->gh_iflags = 0;
 894        gfs2_glock_hold(gl);
 895}
 896
 897/**
 898 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
 899 * @state: the state we're requesting
 900 * @flags: the modifier flags
 901 * @gh: the holder structure
 902 *
 903 * Don't mess with the glock.
 904 *
 905 */
 906
 907void gfs2_holder_reinit(unsigned int state, u16 flags, struct gfs2_holder *gh)
 908{
 909        gh->gh_state = state;
 910        gh->gh_flags = flags;
 911        gh->gh_iflags = 0;
 912        gh->gh_ip = _RET_IP_;
 913        put_pid(gh->gh_owner_pid);
 914        gh->gh_owner_pid = get_pid(task_pid(current));
 915}
 916
 917/**
 918 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
 919 * @gh: the holder structure
 920 *
 921 */
 922
 923void gfs2_holder_uninit(struct gfs2_holder *gh)
 924{
 925        put_pid(gh->gh_owner_pid);
 926        gfs2_glock_put(gh->gh_gl);
 927        gfs2_holder_mark_uninitialized(gh);
 928        gh->gh_ip = 0;
 929}
 930
 931/**
 932 * gfs2_glock_wait - wait on a glock acquisition
 933 * @gh: the glock holder
 934 *
 935 * Returns: 0 on success
 936 */
 937
 938int gfs2_glock_wait(struct gfs2_holder *gh)
 939{
 940        unsigned long time1 = jiffies;
 941
 942        might_sleep();
 943        wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
 944        if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
 945                /* Lengthen the minimum hold time. */
 946                gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
 947                                              GL_GLOCK_HOLD_INCR,
 948                                              GL_GLOCK_MAX_HOLD);
 949        return gh->gh_error;
 950}
 951
 952/**
 953 * handle_callback - process a demote request
 954 * @gl: the glock
 955 * @state: the state the caller wants us to change to
 956 *
 957 * There are only two requests that we are going to see in actual
 958 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
 959 */
 960
 961static void handle_callback(struct gfs2_glock *gl, unsigned int state,
 962                            unsigned long delay, bool remote)
 963{
 964        int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
 965
 966        set_bit(bit, &gl->gl_flags);
 967        if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
 968                gl->gl_demote_state = state;
 969                gl->gl_demote_time = jiffies;
 970        } else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
 971                        gl->gl_demote_state != state) {
 972                gl->gl_demote_state = LM_ST_UNLOCKED;
 973        }
 974        if (gl->gl_ops->go_callback)
 975                gl->gl_ops->go_callback(gl, remote);
 976        trace_gfs2_demote_rq(gl, remote);
 977}
 978
 979void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
 980{
 981        struct va_format vaf;
 982        va_list args;
 983
 984        va_start(args, fmt);
 985
 986        if (seq) {
 987                seq_vprintf(seq, fmt, args);
 988        } else {
 989                vaf.fmt = fmt;
 990                vaf.va = &args;
 991
 992                pr_err("%pV", &vaf);
 993        }
 994
 995        va_end(args);
 996}
 997
 998/**
 999 * add_to_queue - Add a holder to the wait queue (but look for recursion)
1000 * @gh: the holder structure to add
1001 *
1002 * Eventually we should move the recursive locking trap to a
1003 * debugging option or something like that. This is the fast
1004 * path and needs to have the minimum number of distractions.
1005 * 
1006 */
1007
1008static inline void add_to_queue(struct gfs2_holder *gh)
1009__releases(&gl->gl_lockref.lock)
1010__acquires(&gl->gl_lockref.lock)
1011{
1012        struct gfs2_glock *gl = gh->gh_gl;
1013        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1014        struct list_head *insert_pt = NULL;
1015        struct gfs2_holder *gh2;
1016        int try_futile = 0;
1017
1018        BUG_ON(gh->gh_owner_pid == NULL);
1019        if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
1020                BUG();
1021
1022        if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
1023                if (test_bit(GLF_LOCK, &gl->gl_flags))
1024                        try_futile = !may_grant(gl, gh);
1025                if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
1026                        goto fail;
1027        }
1028
1029        list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
1030                if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
1031                    (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
1032                        goto trap_recursive;
1033                if (try_futile &&
1034                    !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
1035fail:
1036                        gh->gh_error = GLR_TRYFAILED;
1037                        gfs2_holder_wake(gh);
1038                        return;
1039                }
1040                if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
1041                        continue;
1042                if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
1043                        insert_pt = &gh2->gh_list;
1044        }
1045        set_bit(GLF_QUEUED, &gl->gl_flags);
1046        trace_gfs2_glock_queue(gh, 1);
1047        gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
1048        gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
1049        if (likely(insert_pt == NULL)) {
1050                list_add_tail(&gh->gh_list, &gl->gl_holders);
1051                if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
1052                        goto do_cancel;
1053                return;
1054        }
1055        list_add_tail(&gh->gh_list, insert_pt);
1056do_cancel:
1057        gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
1058        if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
1059                spin_unlock(&gl->gl_lockref.lock);
1060                if (sdp->sd_lockstruct.ls_ops->lm_cancel)
1061                        sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
1062                spin_lock(&gl->gl_lockref.lock);
1063        }
1064        return;
1065
1066trap_recursive:
1067        pr_err("original: %pSR\n", (void *)gh2->gh_ip);
1068        pr_err("pid: %d\n", pid_nr(gh2->gh_owner_pid));
1069        pr_err("lock type: %d req lock state : %d\n",
1070               gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
1071        pr_err("new: %pSR\n", (void *)gh->gh_ip);
1072        pr_err("pid: %d\n", pid_nr(gh->gh_owner_pid));
1073        pr_err("lock type: %d req lock state : %d\n",
1074               gh->gh_gl->gl_name.ln_type, gh->gh_state);
1075        gfs2_dump_glock(NULL, gl);
1076        BUG();
1077}
1078
1079/**
1080 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
1081 * @gh: the holder structure
1082 *
1083 * if (gh->gh_flags & GL_ASYNC), this never returns an error
1084 *
1085 * Returns: 0, GLR_TRYFAILED, or errno on failure
1086 */
1087
1088int gfs2_glock_nq(struct gfs2_holder *gh)
1089{
1090        struct gfs2_glock *gl = gh->gh_gl;
1091        struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
1092        int error = 0;
1093
1094        if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
1095                return -EIO;
1096
1097        if (test_bit(GLF_LRU, &gl->gl_flags))
1098                gfs2_glock_remove_from_lru(gl);
1099
1100        spin_lock(&gl->gl_lockref.lock);
1101        add_to_queue(gh);
1102        if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) &&
1103                     test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))) {
1104                set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1105                gl->gl_lockref.count++;
1106                __gfs2_glock_queue_work(gl, 0);
1107        }
1108        run_queue(gl, 1);
1109        spin_unlock(&gl->gl_lockref.lock);
1110
1111        if (!(gh->gh_flags & GL_ASYNC))
1112                error = gfs2_glock_wait(gh);
1113
1114        return error;
1115}
1116
1117/**
1118 * gfs2_glock_poll - poll to see if an async request has been completed
1119 * @gh: the holder
1120 *
1121 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1122 */
1123
1124int gfs2_glock_poll(struct gfs2_holder *gh)
1125{
1126        return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1127}
1128
1129/**
1130 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1131 * @gh: the glock holder
1132 *
1133 */
1134
1135void gfs2_glock_dq(struct gfs2_holder *gh)
1136{
1137        struct gfs2_glock *gl = gh->gh_gl;
1138        const struct gfs2_glock_operations *glops = gl->gl_ops;
1139        unsigned delay = 0;
1140        int fast_path = 0;
1141
1142        spin_lock(&gl->gl_lockref.lock);
1143        if (gh->gh_flags & GL_NOCACHE)
1144                handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1145
1146        list_del_init(&gh->gh_list);
1147        clear_bit(HIF_HOLDER, &gh->gh_iflags);
1148        if (find_first_holder(gl) == NULL) {
1149                if (glops->go_unlock) {
1150                        GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1151                        spin_unlock(&gl->gl_lockref.lock);
1152                        glops->go_unlock(gh);
1153                        spin_lock(&gl->gl_lockref.lock);
1154                        clear_bit(GLF_LOCK, &gl->gl_flags);
1155                }
1156                if (list_empty(&gl->gl_holders) &&
1157                    !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1158                    !test_bit(GLF_DEMOTE, &gl->gl_flags))
1159                        fast_path = 1;
1160        }
1161        if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl) &&
1162            (glops->go_flags & GLOF_LRU))
1163                gfs2_glock_add_to_lru(gl);
1164
1165        trace_gfs2_glock_queue(gh, 0);
1166        if (unlikely(!fast_path)) {
1167                gl->gl_lockref.count++;
1168                if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1169                    !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1170                    gl->gl_name.ln_type == LM_TYPE_INODE)
1171                        delay = gl->gl_hold_time;
1172                __gfs2_glock_queue_work(gl, delay);
1173        }
1174        spin_unlock(&gl->gl_lockref.lock);
1175}
1176
1177void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1178{
1179        struct gfs2_glock *gl = gh->gh_gl;
1180        gfs2_glock_dq(gh);
1181        might_sleep();
1182        wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE);
1183}
1184
1185/**
1186 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1187 * @gh: the holder structure
1188 *
1189 */
1190
1191void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1192{
1193        gfs2_glock_dq(gh);
1194        gfs2_holder_uninit(gh);
1195}
1196
1197/**
1198 * gfs2_glock_nq_num - acquire a glock based on lock number
1199 * @sdp: the filesystem
1200 * @number: the lock number
1201 * @glops: the glock operations for the type of glock
1202 * @state: the state to acquire the glock in
1203 * @flags: modifier flags for the acquisition
1204 * @gh: the struct gfs2_holder
1205 *
1206 * Returns: errno
1207 */
1208
1209int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1210                      const struct gfs2_glock_operations *glops,
1211                      unsigned int state, u16 flags, struct gfs2_holder *gh)
1212{
1213        struct gfs2_glock *gl;
1214        int error;
1215
1216        error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1217        if (!error) {
1218                error = gfs2_glock_nq_init(gl, state, flags, gh);
1219                gfs2_glock_put(gl);
1220        }
1221
1222        return error;
1223}
1224
1225/**
1226 * glock_compare - Compare two struct gfs2_glock structures for sorting
1227 * @arg_a: the first structure
1228 * @arg_b: the second structure
1229 *
1230 */
1231
1232static int glock_compare(const void *arg_a, const void *arg_b)
1233{
1234        const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1235        const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1236        const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1237        const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1238
1239        if (a->ln_number > b->ln_number)
1240                return 1;
1241        if (a->ln_number < b->ln_number)
1242                return -1;
1243        BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1244        return 0;
1245}
1246
1247/**
1248 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1249 * @num_gh: the number of structures
1250 * @ghs: an array of struct gfs2_holder structures
1251 *
1252 * Returns: 0 on success (all glocks acquired),
1253 *          errno on failure (no glocks acquired)
1254 */
1255
1256static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1257                     struct gfs2_holder **p)
1258{
1259        unsigned int x;
1260        int error = 0;
1261
1262        for (x = 0; x < num_gh; x++)
1263                p[x] = &ghs[x];
1264
1265        sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1266
1267        for (x = 0; x < num_gh; x++) {
1268                p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1269
1270                error = gfs2_glock_nq(p[x]);
1271                if (error) {
1272                        while (x--)
1273                                gfs2_glock_dq(p[x]);
1274                        break;
1275                }
1276        }
1277
1278        return error;
1279}
1280
1281/**
1282 * gfs2_glock_nq_m - acquire multiple glocks
1283 * @num_gh: the number of structures
1284 * @ghs: an array of struct gfs2_holder structures
1285 *
1286 *
1287 * Returns: 0 on success (all glocks acquired),
1288 *          errno on failure (no glocks acquired)
1289 */
1290
1291int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1292{
1293        struct gfs2_holder *tmp[4];
1294        struct gfs2_holder **pph = tmp;
1295        int error = 0;
1296
1297        switch(num_gh) {
1298        case 0:
1299                return 0;
1300        case 1:
1301                ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1302                return gfs2_glock_nq(ghs);
1303        default:
1304                if (num_gh <= 4)
1305                        break;
1306                pph = kmalloc_array(num_gh, sizeof(struct gfs2_holder *),
1307                                    GFP_NOFS);
1308                if (!pph)
1309                        return -ENOMEM;
1310        }
1311
1312        error = nq_m_sync(num_gh, ghs, pph);
1313
1314        if (pph != tmp)
1315                kfree(pph);
1316
1317        return error;
1318}
1319
1320/**
1321 * gfs2_glock_dq_m - release multiple glocks
1322 * @num_gh: the number of structures
1323 * @ghs: an array of struct gfs2_holder structures
1324 *
1325 */
1326
1327void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1328{
1329        while (num_gh--)
1330                gfs2_glock_dq(&ghs[num_gh]);
1331}
1332
1333void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1334{
1335        unsigned long delay = 0;
1336        unsigned long holdtime;
1337        unsigned long now = jiffies;
1338
1339        gfs2_glock_hold(gl);
1340        holdtime = gl->gl_tchange + gl->gl_hold_time;
1341        if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1342            gl->gl_name.ln_type == LM_TYPE_INODE) {
1343                if (time_before(now, holdtime))
1344                        delay = holdtime - now;
1345                if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1346                        delay = gl->gl_hold_time;
1347        }
1348
1349        spin_lock(&gl->gl_lockref.lock);
1350        handle_callback(gl, state, delay, true);
1351        __gfs2_glock_queue_work(gl, delay);
1352        spin_unlock(&gl->gl_lockref.lock);
1353}
1354
1355/**
1356 * gfs2_should_freeze - Figure out if glock should be frozen
1357 * @gl: The glock in question
1358 *
1359 * Glocks are not frozen if (a) the result of the dlm operation is
1360 * an error, (b) the locking operation was an unlock operation or
1361 * (c) if there is a "noexp" flagged request anywhere in the queue
1362 *
1363 * Returns: 1 if freezing should occur, 0 otherwise
1364 */
1365
1366static int gfs2_should_freeze(const struct gfs2_glock *gl)
1367{
1368        const struct gfs2_holder *gh;
1369
1370        if (gl->gl_reply & ~LM_OUT_ST_MASK)
1371                return 0;
1372        if (gl->gl_target == LM_ST_UNLOCKED)
1373                return 0;
1374
1375        list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1376                if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1377                        continue;
1378                if (LM_FLAG_NOEXP & gh->gh_flags)
1379                        return 0;
1380        }
1381
1382        return 1;
1383}
1384
1385/**
1386 * gfs2_glock_complete - Callback used by locking
1387 * @gl: Pointer to the glock
1388 * @ret: The return value from the dlm
1389 *
1390 * The gl_reply field is under the gl_lockref.lock lock so that it is ok
1391 * to use a bitfield shared with other glock state fields.
1392 */
1393
1394void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1395{
1396        struct lm_lockstruct *ls = &gl->gl_name.ln_sbd->sd_lockstruct;
1397
1398        spin_lock(&gl->gl_lockref.lock);
1399        gl->gl_reply = ret;
1400
1401        if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1402                if (gfs2_should_freeze(gl)) {
1403                        set_bit(GLF_FROZEN, &gl->gl_flags);
1404                        spin_unlock(&gl->gl_lockref.lock);
1405                        return;
1406                }
1407        }
1408
1409        gl->gl_lockref.count++;
1410        set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1411        __gfs2_glock_queue_work(gl, 0);
1412        spin_unlock(&gl->gl_lockref.lock);
1413}
1414
1415static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
1416{
1417        struct gfs2_glock *gla, *glb;
1418
1419        gla = list_entry(a, struct gfs2_glock, gl_lru);
1420        glb = list_entry(b, struct gfs2_glock, gl_lru);
1421
1422        if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1423                return 1;
1424        if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1425                return -1;
1426
1427        return 0;
1428}
1429
1430/**
1431 * gfs2_dispose_glock_lru - Demote a list of glocks
1432 * @list: The list to dispose of
1433 *
1434 * Disposing of glocks may involve disk accesses, so that here we sort
1435 * the glocks by number (i.e. disk location of the inodes) so that if
1436 * there are any such accesses, they'll be sent in order (mostly).
1437 *
1438 * Must be called under the lru_lock, but may drop and retake this
1439 * lock. While the lru_lock is dropped, entries may vanish from the
1440 * list, but no new entries will appear on the list (since it is
1441 * private)
1442 */
1443
1444static void gfs2_dispose_glock_lru(struct list_head *list)
1445__releases(&lru_lock)
1446__acquires(&lru_lock)
1447{
1448        struct gfs2_glock *gl;
1449
1450        list_sort(NULL, list, glock_cmp);
1451
1452        while(!list_empty(list)) {
1453                gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1454                list_del_init(&gl->gl_lru);
1455                if (!spin_trylock(&gl->gl_lockref.lock)) {
1456add_back_to_lru:
1457                        list_add(&gl->gl_lru, &lru_list);
1458                        atomic_inc(&lru_count);
1459                        continue;
1460                }
1461                if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1462                        spin_unlock(&gl->gl_lockref.lock);
1463                        goto add_back_to_lru;
1464                }
1465                clear_bit(GLF_LRU, &gl->gl_flags);
1466                gl->gl_lockref.count++;
1467                if (demote_ok(gl))
1468                        handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1469                WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1470                __gfs2_glock_queue_work(gl, 0);
1471                spin_unlock(&gl->gl_lockref.lock);
1472                cond_resched_lock(&lru_lock);
1473        }
1474}
1475
1476/**
1477 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1478 * @nr: The number of entries to scan
1479 *
1480 * This function selects the entries on the LRU which are able to
1481 * be demoted, and then kicks off the process by calling
1482 * gfs2_dispose_glock_lru() above.
1483 */
1484
1485static long gfs2_scan_glock_lru(int nr)
1486{
1487        struct gfs2_glock *gl;
1488        LIST_HEAD(skipped);
1489        LIST_HEAD(dispose);
1490        long freed = 0;
1491
1492        spin_lock(&lru_lock);
1493        while ((nr-- >= 0) && !list_empty(&lru_list)) {
1494                gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1495
1496                /* Test for being demotable */
1497                if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
1498                        list_move(&gl->gl_lru, &dispose);
1499                        atomic_dec(&lru_count);
1500                        freed++;
1501                        continue;
1502                }
1503
1504                list_move(&gl->gl_lru, &skipped);
1505        }
1506        list_splice(&skipped, &lru_list);
1507        if (!list_empty(&dispose))
1508                gfs2_dispose_glock_lru(&dispose);
1509        spin_unlock(&lru_lock);
1510
1511        return freed;
1512}
1513
1514static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
1515                                            struct shrink_control *sc)
1516{
1517        if (!(sc->gfp_mask & __GFP_FS))
1518                return SHRINK_STOP;
1519        return gfs2_scan_glock_lru(sc->nr_to_scan);
1520}
1521
1522static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
1523                                             struct shrink_control *sc)
1524{
1525        return vfs_pressure_ratio(atomic_read(&lru_count));
1526}
1527
1528static struct shrinker glock_shrinker = {
1529        .seeks = DEFAULT_SEEKS,
1530        .count_objects = gfs2_glock_shrink_count,
1531        .scan_objects = gfs2_glock_shrink_scan,
1532};
1533
1534/**
1535 * examine_bucket - Call a function for glock in a hash bucket
1536 * @examiner: the function
1537 * @sdp: the filesystem
1538 * @bucket: the bucket
1539 *
1540 * Note that the function can be called multiple times on the same
1541 * object.  So the user must ensure that the function can cope with
1542 * that.
1543 */
1544
1545static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1546{
1547        struct gfs2_glock *gl;
1548        struct rhashtable_iter iter;
1549
1550        rhashtable_walk_enter(&gl_hash_table, &iter);
1551
1552        do {
1553                rhashtable_walk_start(&iter);
1554
1555                while ((gl = rhashtable_walk_next(&iter)) && !IS_ERR(gl))
1556                        if (gl->gl_name.ln_sbd == sdp &&
1557                            lockref_get_not_dead(&gl->gl_lockref))
1558                                examiner(gl);
1559
1560                rhashtable_walk_stop(&iter);
1561        } while (cond_resched(), gl == ERR_PTR(-EAGAIN));
1562
1563        rhashtable_walk_exit(&iter);
1564}
1565
1566/**
1567 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1568 * @gl: The glock to thaw
1569 *
1570 */
1571
1572static void thaw_glock(struct gfs2_glock *gl)
1573{
1574        if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags)) {
1575                gfs2_glock_put(gl);
1576                return;
1577        }
1578        set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1579        gfs2_glock_queue_work(gl, 0);
1580}
1581
1582/**
1583 * clear_glock - look at a glock and see if we can free it from glock cache
1584 * @gl: the glock to look at
1585 *
1586 */
1587
1588static void clear_glock(struct gfs2_glock *gl)
1589{
1590        gfs2_glock_remove_from_lru(gl);
1591
1592        spin_lock(&gl->gl_lockref.lock);
1593        if (gl->gl_state != LM_ST_UNLOCKED)
1594                handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1595        __gfs2_glock_queue_work(gl, 0);
1596        spin_unlock(&gl->gl_lockref.lock);
1597}
1598
1599/**
1600 * gfs2_glock_thaw - Thaw any frozen glocks
1601 * @sdp: The super block
1602 *
1603 */
1604
1605void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1606{
1607        glock_hash_walk(thaw_glock, sdp);
1608}
1609
1610static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1611{
1612        spin_lock(&gl->gl_lockref.lock);
1613        gfs2_dump_glock(seq, gl);
1614        spin_unlock(&gl->gl_lockref.lock);
1615}
1616
1617static void dump_glock_func(struct gfs2_glock *gl)
1618{
1619        dump_glock(NULL, gl);
1620}
1621
1622/**
1623 * gfs2_gl_hash_clear - Empty out the glock hash table
1624 * @sdp: the filesystem
1625 * @wait: wait until it's all gone
1626 *
1627 * Called when unmounting the filesystem.
1628 */
1629
1630void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1631{
1632        set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1633        flush_workqueue(glock_workqueue);
1634        glock_hash_walk(clear_glock, sdp);
1635        flush_workqueue(glock_workqueue);
1636        wait_event_timeout(sdp->sd_glock_wait,
1637                           atomic_read(&sdp->sd_glock_disposal) == 0,
1638                           HZ * 600);
1639        glock_hash_walk(dump_glock_func, sdp);
1640}
1641
1642void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1643{
1644        struct gfs2_glock *gl = ip->i_gl;
1645        int ret;
1646
1647        ret = gfs2_truncatei_resume(ip);
1648        gfs2_assert_withdraw(gl->gl_name.ln_sbd, ret == 0);
1649
1650        spin_lock(&gl->gl_lockref.lock);
1651        clear_bit(GLF_LOCK, &gl->gl_flags);
1652        run_queue(gl, 1);
1653        spin_unlock(&gl->gl_lockref.lock);
1654}
1655
1656static const char *state2str(unsigned state)
1657{
1658        switch(state) {
1659        case LM_ST_UNLOCKED:
1660                return "UN";
1661        case LM_ST_SHARED:
1662                return "SH";
1663        case LM_ST_DEFERRED:
1664                return "DF";
1665        case LM_ST_EXCLUSIVE:
1666                return "EX";
1667        }
1668        return "??";
1669}
1670
1671static const char *hflags2str(char *buf, u16 flags, unsigned long iflags)
1672{
1673        char *p = buf;
1674        if (flags & LM_FLAG_TRY)
1675                *p++ = 't';
1676        if (flags & LM_FLAG_TRY_1CB)
1677                *p++ = 'T';
1678        if (flags & LM_FLAG_NOEXP)
1679                *p++ = 'e';
1680        if (flags & LM_FLAG_ANY)
1681                *p++ = 'A';
1682        if (flags & LM_FLAG_PRIORITY)
1683                *p++ = 'p';
1684        if (flags & GL_ASYNC)
1685                *p++ = 'a';
1686        if (flags & GL_EXACT)
1687                *p++ = 'E';
1688        if (flags & GL_NOCACHE)
1689                *p++ = 'c';
1690        if (test_bit(HIF_HOLDER, &iflags))
1691                *p++ = 'H';
1692        if (test_bit(HIF_WAIT, &iflags))
1693                *p++ = 'W';
1694        if (test_bit(HIF_FIRST, &iflags))
1695                *p++ = 'F';
1696        *p = 0;
1697        return buf;
1698}
1699
1700/**
1701 * dump_holder - print information about a glock holder
1702 * @seq: the seq_file struct
1703 * @gh: the glock holder
1704 *
1705 */
1706
1707static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
1708{
1709        struct task_struct *gh_owner = NULL;
1710        char flags_buf[32];
1711
1712        rcu_read_lock();
1713        if (gh->gh_owner_pid)
1714                gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1715        gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1716                       state2str(gh->gh_state),
1717                       hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1718                       gh->gh_error,
1719                       gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1720                       gh_owner ? gh_owner->comm : "(ended)",
1721                       (void *)gh->gh_ip);
1722        rcu_read_unlock();
1723}
1724
1725static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1726{
1727        const unsigned long *gflags = &gl->gl_flags;
1728        char *p = buf;
1729
1730        if (test_bit(GLF_LOCK, gflags))
1731                *p++ = 'l';
1732        if (test_bit(GLF_DEMOTE, gflags))
1733                *p++ = 'D';
1734        if (test_bit(GLF_PENDING_DEMOTE, gflags))
1735                *p++ = 'd';
1736        if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1737                *p++ = 'p';
1738        if (test_bit(GLF_DIRTY, gflags))
1739                *p++ = 'y';
1740        if (test_bit(GLF_LFLUSH, gflags))
1741                *p++ = 'f';
1742        if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1743                *p++ = 'i';
1744        if (test_bit(GLF_REPLY_PENDING, gflags))
1745                *p++ = 'r';
1746        if (test_bit(GLF_INITIAL, gflags))
1747                *p++ = 'I';
1748        if (test_bit(GLF_FROZEN, gflags))
1749                *p++ = 'F';
1750        if (test_bit(GLF_QUEUED, gflags))
1751                *p++ = 'q';
1752        if (test_bit(GLF_LRU, gflags))
1753                *p++ = 'L';
1754        if (gl->gl_object)
1755                *p++ = 'o';
1756        if (test_bit(GLF_BLOCKING, gflags))
1757                *p++ = 'b';
1758        *p = 0;
1759        return buf;
1760}
1761
1762/**
1763 * gfs2_dump_glock - print information about a glock
1764 * @seq: The seq_file struct
1765 * @gl: the glock
1766 *
1767 * The file format is as follows:
1768 * One line per object, capital letters are used to indicate objects
1769 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1770 * other objects are indented by a single space and follow the glock to
1771 * which they are related. Fields are indicated by lower case letters
1772 * followed by a colon and the field value, except for strings which are in
1773 * [] so that its possible to see if they are composed of spaces for
1774 * example. The field's are n = number (id of the object), f = flags,
1775 * t = type, s = state, r = refcount, e = error, p = pid.
1776 *
1777 */
1778
1779void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1780{
1781        const struct gfs2_glock_operations *glops = gl->gl_ops;
1782        unsigned long long dtime;
1783        const struct gfs2_holder *gh;
1784        char gflags_buf[32];
1785
1786        dtime = jiffies - gl->gl_demote_time;
1787        dtime *= 1000000/HZ; /* demote time in uSec */
1788        if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1789                dtime = 0;
1790        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",
1791                  state2str(gl->gl_state),
1792                  gl->gl_name.ln_type,
1793                  (unsigned long long)gl->gl_name.ln_number,
1794                  gflags2str(gflags_buf, gl),
1795                  state2str(gl->gl_target),
1796                  state2str(gl->gl_demote_state), dtime,
1797                  atomic_read(&gl->gl_ail_count),
1798                  atomic_read(&gl->gl_revokes),
1799                  (int)gl->gl_lockref.count, gl->gl_hold_time);
1800
1801        list_for_each_entry(gh, &gl->gl_holders, gh_list)
1802                dump_holder(seq, gh);
1803
1804        if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1805                glops->go_dump(seq, gl);
1806}
1807
1808static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1809{
1810        struct gfs2_glock *gl = iter_ptr;
1811
1812        seq_printf(seq, "G: n:%u/%llx rtt:%llu/%llu rttb:%llu/%llu irt:%llu/%llu dcnt: %llu qcnt: %llu\n",
1813                   gl->gl_name.ln_type,
1814                   (unsigned long long)gl->gl_name.ln_number,
1815                   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1816                   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1817                   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1818                   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1819                   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1820                   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1821                   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1822                   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1823        return 0;
1824}
1825
1826static const char *gfs2_gltype[] = {
1827        "type",
1828        "reserved",
1829        "nondisk",
1830        "inode",
1831        "rgrp",
1832        "meta",
1833        "iopen",
1834        "flock",
1835        "plock",
1836        "quota",
1837        "journal",
1838};
1839
1840static const char *gfs2_stype[] = {
1841        [GFS2_LKS_SRTT]         = "srtt",
1842        [GFS2_LKS_SRTTVAR]      = "srttvar",
1843        [GFS2_LKS_SRTTB]        = "srttb",
1844        [GFS2_LKS_SRTTVARB]     = "srttvarb",
1845        [GFS2_LKS_SIRT]         = "sirt",
1846        [GFS2_LKS_SIRTVAR]      = "sirtvar",
1847        [GFS2_LKS_DCOUNT]       = "dlm",
1848        [GFS2_LKS_QCOUNT]       = "queue",
1849};
1850
1851#define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1852
1853static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1854{
1855        struct gfs2_sbd *sdp = seq->private;
1856        loff_t pos = *(loff_t *)iter_ptr;
1857        unsigned index = pos >> 3;
1858        unsigned subindex = pos & 0x07;
1859        int i;
1860
1861        if (index == 0 && subindex != 0)
1862                return 0;
1863
1864        seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1865                   (index == 0) ? "cpu": gfs2_stype[subindex]);
1866
1867        for_each_possible_cpu(i) {
1868                const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1869
1870                if (index == 0)
1871                        seq_printf(seq, " %15u", i);
1872                else
1873                        seq_printf(seq, " %15llu", (unsigned long long)lkstats->
1874                                   lkstats[index - 1].stats[subindex]);
1875        }
1876        seq_putc(seq, '\n');
1877        return 0;
1878}
1879
1880int __init gfs2_glock_init(void)
1881{
1882        int i, ret;
1883
1884        ret = rhashtable_init(&gl_hash_table, &ht_parms);
1885        if (ret < 0)
1886                return ret;
1887
1888        glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1889                                          WQ_HIGHPRI | WQ_FREEZABLE, 0);
1890        if (!glock_workqueue) {
1891                rhashtable_destroy(&gl_hash_table);
1892                return -ENOMEM;
1893        }
1894        gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1895                                                WQ_MEM_RECLAIM | WQ_FREEZABLE,
1896                                                0);
1897        if (!gfs2_delete_workqueue) {
1898                destroy_workqueue(glock_workqueue);
1899                rhashtable_destroy(&gl_hash_table);
1900                return -ENOMEM;
1901        }
1902
1903        ret = register_shrinker(&glock_shrinker);
1904        if (ret) {
1905                destroy_workqueue(gfs2_delete_workqueue);
1906                destroy_workqueue(glock_workqueue);
1907                rhashtable_destroy(&gl_hash_table);
1908                return ret;
1909        }
1910
1911        for (i = 0; i < GLOCK_WAIT_TABLE_SIZE; i++)
1912                init_waitqueue_head(glock_wait_table + i);
1913
1914        return 0;
1915}
1916
1917void gfs2_glock_exit(void)
1918{
1919        unregister_shrinker(&glock_shrinker);
1920        rhashtable_destroy(&gl_hash_table);
1921        destroy_workqueue(glock_workqueue);
1922        destroy_workqueue(gfs2_delete_workqueue);
1923}
1924
1925static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi, loff_t n)
1926{
1927        struct gfs2_glock *gl = gi->gl;
1928
1929        if (gl) {
1930                if (n == 0)
1931                        return;
1932                if (!lockref_put_not_zero(&gl->gl_lockref))
1933                        gfs2_glock_queue_put(gl);
1934        }
1935        for (;;) {
1936                gl = rhashtable_walk_next(&gi->hti);
1937                if (IS_ERR_OR_NULL(gl)) {
1938                        if (gl == ERR_PTR(-EAGAIN)) {
1939                                n = 1;
1940                                continue;
1941                        }
1942                        gl = NULL;
1943                        break;
1944                }
1945                if (gl->gl_name.ln_sbd != gi->sdp)
1946                        continue;
1947                if (n <= 1) {
1948                        if (!lockref_get_not_dead(&gl->gl_lockref))
1949                                continue;
1950                        break;
1951                } else {
1952                        if (__lockref_is_dead(&gl->gl_lockref))
1953                                continue;
1954                        n--;
1955                }
1956        }
1957        gi->gl = gl;
1958}
1959
1960static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1961        __acquires(RCU)
1962{
1963        struct gfs2_glock_iter *gi = seq->private;
1964        loff_t n;
1965
1966        /*
1967         * We can either stay where we are, skip to the next hash table
1968         * entry, or start from the beginning.
1969         */
1970        if (*pos < gi->last_pos) {
1971                rhashtable_walk_exit(&gi->hti);
1972                rhashtable_walk_enter(&gl_hash_table, &gi->hti);
1973                n = *pos + 1;
1974        } else {
1975                n = *pos - gi->last_pos;
1976        }
1977
1978        rhashtable_walk_start(&gi->hti);
1979
1980        gfs2_glock_iter_next(gi, n);
1981        gi->last_pos = *pos;
1982        return gi->gl;
1983}
1984
1985static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1986                                 loff_t *pos)
1987{
1988        struct gfs2_glock_iter *gi = seq->private;
1989
1990        (*pos)++;
1991        gi->last_pos = *pos;
1992        gfs2_glock_iter_next(gi, 1);
1993        return gi->gl;
1994}
1995
1996static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1997        __releases(RCU)
1998{
1999        struct gfs2_glock_iter *gi = seq->private;
2000
2001        rhashtable_walk_stop(&gi->hti);
2002}
2003
2004static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
2005{
2006        dump_glock(seq, iter_ptr);
2007        return 0;
2008}
2009
2010static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
2011{
2012        preempt_disable();
2013        if (*pos >= GFS2_NR_SBSTATS)
2014                return NULL;
2015        return pos;
2016}
2017
2018static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
2019                                   loff_t *pos)
2020{
2021        (*pos)++;
2022        if (*pos >= GFS2_NR_SBSTATS)
2023                return NULL;
2024        return pos;
2025}
2026
2027static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
2028{
2029        preempt_enable();
2030}
2031
2032static const struct seq_operations gfs2_glock_seq_ops = {
2033        .start = gfs2_glock_seq_start,
2034        .next  = gfs2_glock_seq_next,
2035        .stop  = gfs2_glock_seq_stop,
2036        .show  = gfs2_glock_seq_show,
2037};
2038
2039static const struct seq_operations gfs2_glstats_seq_ops = {
2040        .start = gfs2_glock_seq_start,
2041        .next  = gfs2_glock_seq_next,
2042        .stop  = gfs2_glock_seq_stop,
2043        .show  = gfs2_glstats_seq_show,
2044};
2045
2046static const struct seq_operations gfs2_sbstats_seq_ops = {
2047        .start = gfs2_sbstats_seq_start,
2048        .next  = gfs2_sbstats_seq_next,
2049        .stop  = gfs2_sbstats_seq_stop,
2050        .show  = gfs2_sbstats_seq_show,
2051};
2052
2053#define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
2054
2055static int __gfs2_glocks_open(struct inode *inode, struct file *file,
2056                              const struct seq_operations *ops)
2057{
2058        int ret = seq_open_private(file, ops, sizeof(struct gfs2_glock_iter));
2059        if (ret == 0) {
2060                struct seq_file *seq = file->private_data;
2061                struct gfs2_glock_iter *gi = seq->private;
2062
2063                gi->sdp = inode->i_private;
2064                seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2065                if (seq->buf)
2066                        seq->size = GFS2_SEQ_GOODSIZE;
2067                /*
2068                 * Initially, we are "before" the first hash table entry; the
2069                 * first call to rhashtable_walk_next gets us the first entry.
2070                 */
2071                gi->last_pos = -1;
2072                gi->gl = NULL;
2073                rhashtable_walk_enter(&gl_hash_table, &gi->hti);
2074        }
2075        return ret;
2076}
2077
2078static int gfs2_glocks_open(struct inode *inode, struct file *file)
2079{
2080        return __gfs2_glocks_open(inode, file, &gfs2_glock_seq_ops);
2081}
2082
2083static int gfs2_glocks_release(struct inode *inode, struct file *file)
2084{
2085        struct seq_file *seq = file->private_data;
2086        struct gfs2_glock_iter *gi = seq->private;
2087
2088        if (gi->gl)
2089                gfs2_glock_put(gi->gl);
2090        rhashtable_walk_exit(&gi->hti);
2091        return seq_release_private(inode, file);
2092}
2093
2094static int gfs2_glstats_open(struct inode *inode, struct file *file)
2095{
2096        return __gfs2_glocks_open(inode, file, &gfs2_glstats_seq_ops);
2097}
2098
2099static int gfs2_sbstats_open(struct inode *inode, struct file *file)
2100{
2101        int ret = seq_open(file, &gfs2_sbstats_seq_ops);
2102        if (ret == 0) {
2103                struct seq_file *seq = file->private_data;
2104                seq->private = inode->i_private;  /* sdp */
2105        }
2106        return ret;
2107}
2108
2109static const struct file_operations gfs2_glocks_fops = {
2110        .owner   = THIS_MODULE,
2111        .open    = gfs2_glocks_open,
2112        .read    = seq_read,
2113        .llseek  = seq_lseek,
2114        .release = gfs2_glocks_release,
2115};
2116
2117static const struct file_operations gfs2_glstats_fops = {
2118        .owner   = THIS_MODULE,
2119        .open    = gfs2_glstats_open,
2120        .read    = seq_read,
2121        .llseek  = seq_lseek,
2122        .release = gfs2_glocks_release,
2123};
2124
2125static const struct file_operations gfs2_sbstats_fops = {
2126        .owner   = THIS_MODULE,
2127        .open    = gfs2_sbstats_open,
2128        .read    = seq_read,
2129        .llseek  = seq_lseek,
2130        .release = seq_release,
2131};
2132
2133int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
2134{
2135        struct dentry *dent;
2136
2137        dent = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
2138        if (IS_ERR_OR_NULL(dent))
2139                goto fail;
2140        sdp->debugfs_dir = dent;
2141
2142        dent = debugfs_create_file("glocks",
2143                                   S_IFREG | S_IRUGO,
2144                                   sdp->debugfs_dir, sdp,
2145                                   &gfs2_glocks_fops);
2146        if (IS_ERR_OR_NULL(dent))
2147                goto fail;
2148        sdp->debugfs_dentry_glocks = dent;
2149
2150        dent = debugfs_create_file("glstats",
2151                                   S_IFREG | S_IRUGO,
2152                                   sdp->debugfs_dir, sdp,
2153                                   &gfs2_glstats_fops);
2154        if (IS_ERR_OR_NULL(dent))
2155                goto fail;
2156        sdp->debugfs_dentry_glstats = dent;
2157
2158        dent = debugfs_create_file("sbstats",
2159                                   S_IFREG | S_IRUGO,
2160                                   sdp->debugfs_dir, sdp,
2161                                   &gfs2_sbstats_fops);
2162        if (IS_ERR_OR_NULL(dent))
2163                goto fail;
2164        sdp->debugfs_dentry_sbstats = dent;
2165
2166        return 0;
2167fail:
2168        gfs2_delete_debugfs_file(sdp);
2169        return dent ? PTR_ERR(dent) : -ENOMEM;
2170}
2171
2172void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2173{
2174        if (sdp->debugfs_dir) {
2175                if (sdp->debugfs_dentry_glocks) {
2176                        debugfs_remove(sdp->debugfs_dentry_glocks);
2177                        sdp->debugfs_dentry_glocks = NULL;
2178                }
2179                if (sdp->debugfs_dentry_glstats) {
2180                        debugfs_remove(sdp->debugfs_dentry_glstats);
2181                        sdp->debugfs_dentry_glstats = NULL;
2182                }
2183                if (sdp->debugfs_dentry_sbstats) {
2184                        debugfs_remove(sdp->debugfs_dentry_sbstats);
2185                        sdp->debugfs_dentry_sbstats = NULL;
2186                }
2187                debugfs_remove(sdp->debugfs_dir);
2188                sdp->debugfs_dir = NULL;
2189        }
2190}
2191
2192int gfs2_register_debugfs(void)
2193{
2194        gfs2_root = debugfs_create_dir("gfs2", NULL);
2195        if (IS_ERR(gfs2_root))
2196                return PTR_ERR(gfs2_root);
2197        return gfs2_root ? 0 : -ENOMEM;
2198}
2199
2200void gfs2_unregister_debugfs(void)
2201{
2202        debugfs_remove(gfs2_root);
2203        gfs2_root = NULL;
2204}
2205