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
  53struct 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
  60typedef void (*glock_examiner) (struct gfs2_glock * gl);
  61
  62static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
 
 
 
  63
  64static struct dentry *gfs2_root;
  65static struct workqueue_struct *glock_workqueue;
  66struct workqueue_struct *gfs2_delete_workqueue;
  67static LIST_HEAD(lru_list);
  68static atomic_t lru_count = ATOMIC_INIT(0);
  69static DEFINE_SPINLOCK(lru_lock);
  70
  71#define GFS2_GL_HASH_SHIFT      15
  72#define GFS2_GL_HASH_SIZE       (1 << GFS2_GL_HASH_SHIFT)
  73
  74static 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
  81static struct rhashtable gl_hash_table;
  82
  83void gfs2_glock_free(struct gfs2_glock *gl)
 
 
 
 
 
 
 
 
 
 
  84{
  85	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  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	if (atomic_dec_and_test(&sdp->sd_glock_disposal))
  94		wake_up(&sdp->sd_glock_wait);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  95}
  96
  97/**
  98 * gfs2_glock_hold() - increment reference count on glock
  99 * @gl: The glock to hold
 100 *
 101 */
 102
 103static void gfs2_glock_hold(struct gfs2_glock *gl)
 104{
 105	GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
 106	lockref_get(&gl->gl_lockref);
 
 107}
 108
 109/**
 110 * demote_ok - Check to see if it's ok to unlock a glock
 111 * @gl: the glock
 112 *
 113 * Returns: 1 if it's ok
 114 */
 115
 116static int demote_ok(const struct gfs2_glock *gl)
 117{
 118	const struct gfs2_glock_operations *glops = gl->gl_ops;
 119
 120	if (gl->gl_state == LM_ST_UNLOCKED)
 121		return 0;
 122	if (!list_empty(&gl->gl_holders))
 123		return 0;
 124	if (glops->go_demote_ok)
 125		return glops->go_demote_ok(gl);
 126	return 1;
 127}
 128
 129
 130void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
 131{
 
 
 
 132	spin_lock(&lru_lock);
 133
 134	if (!list_empty(&gl->gl_lru))
 135		list_del_init(&gl->gl_lru);
 136	else
 
 137		atomic_inc(&lru_count);
 
 138
 139	list_add_tail(&gl->gl_lru, &lru_list);
 140	set_bit(GLF_LRU, &gl->gl_flags);
 141	spin_unlock(&lru_lock);
 142}
 143
 144static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
 145{
 
 
 
 146	spin_lock(&lru_lock);
 147	if (!list_empty(&gl->gl_lru)) {
 148		list_del_init(&gl->gl_lru);
 149		atomic_dec(&lru_count);
 150		clear_bit(GLF_LRU, &gl->gl_flags);
 151	}
 152	spin_unlock(&lru_lock);
 153}
 154
 155/**
 156 * gfs2_glock_put() - Decrement reference count on glock
 157 * @gl: The glock to put
 158 *
 159 */
 
 
 
 
 
 
 
 
 
 
 
 
 160
 161void gfs2_glock_put(struct gfs2_glock *gl)
 
 
 
 
 
 
 162{
 163	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 164	struct address_space *mapping = gfs2_glock2aspace(gl);
 165
 166	if (lockref_put_or_lock(&gl->gl_lockref))
 167		return;
 168
 169	lockref_mark_dead(&gl->gl_lockref);
 170
 171	gfs2_glock_remove_from_lru(gl);
 172	spin_unlock(&gl->gl_lockref.lock);
 173	rhashtable_remove_fast(&gl_hash_table, &gl->gl_node, ht_parms);
 174	GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
 175	GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
 
 
 
 
 176	trace_gfs2_glock_put(gl);
 177	sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
 178}
 179
 
 
 
 
 
 
 
 
 180/**
 181 * may_grant - check if its ok to grant a new lock
 182 * @gl: The glock
 183 * @gh: The lock request which we wish to grant
 184 *
 185 * Returns: true if its ok to grant the lock
 186 */
 187
 188static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
 189{
 190	const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
 191	if ((gh->gh_state == LM_ST_EXCLUSIVE ||
 192	     gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
 193		return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 194	if (gl->gl_state == gh->gh_state)
 195		return 1;
 196	if (gh->gh_flags & GL_EXACT)
 197		return 0;
 198	if (gl->gl_state == LM_ST_EXCLUSIVE) {
 199		if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
 200			return 1;
 201		if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
 202			return 1;
 203	}
 204	if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
 205		return 1;
 206	return 0;
 207}
 208
 209static void gfs2_holder_wake(struct gfs2_holder *gh)
 210{
 211	clear_bit(HIF_WAIT, &gh->gh_iflags);
 212	smp_mb__after_atomic();
 213	wake_up_bit(&gh->gh_iflags, HIF_WAIT);
 
 
 
 
 
 214}
 215
 216/**
 217 * do_error - Something unexpected has happened during a lock request
 218 *
 
 219 */
 220
 221static inline void do_error(struct gfs2_glock *gl, const int ret)
 222{
 223	struct gfs2_holder *gh, *tmp;
 224
 225	list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
 226		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
 227			continue;
 228		if (ret & LM_OUT_ERROR)
 229			gh->gh_error = -EIO;
 230		else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
 231			gh->gh_error = GLR_TRYFAILED;
 232		else
 233			continue;
 234		list_del_init(&gh->gh_list);
 235		trace_gfs2_glock_queue(gh, 0);
 236		gfs2_holder_wake(gh);
 237	}
 238}
 239
 240/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 241 * do_promote - promote as many requests as possible on the current queue
 242 * @gl: The glock
 243 * 
 244 * Returns: 1 if there is a blocked holder at the head of the list, or 2
 245 *          if a type specific operation is underway.
 246 */
 247
 248static int do_promote(struct gfs2_glock *gl)
 249__releases(&gl->gl_lockref.lock)
 250__acquires(&gl->gl_lockref.lock)
 251{
 252	const struct gfs2_glock_operations *glops = gl->gl_ops;
 253	struct gfs2_holder *gh, *tmp;
 254	int ret;
 255
 256restart:
 257	list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
 258		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
 259			continue;
 260		if (may_grant(gl, gh)) {
 261			if (gh->gh_list.prev == &gl->gl_holders &&
 262			    glops->go_lock) {
 263				spin_unlock(&gl->gl_lockref.lock);
 264				/* FIXME: eliminate this eventually */
 265				ret = glops->go_lock(gh);
 266				spin_lock(&gl->gl_lockref.lock);
 267				if (ret) {
 268					if (ret == 1)
 269						return 2;
 270					gh->gh_error = ret;
 271					list_del_init(&gh->gh_list);
 272					trace_gfs2_glock_queue(gh, 0);
 273					gfs2_holder_wake(gh);
 274					goto restart;
 275				}
 276				set_bit(HIF_HOLDER, &gh->gh_iflags);
 277				trace_gfs2_promote(gh, 1);
 278				gfs2_holder_wake(gh);
 279				goto restart;
 280			}
 281			set_bit(HIF_HOLDER, &gh->gh_iflags);
 282			trace_gfs2_promote(gh, 0);
 283			gfs2_holder_wake(gh);
 284			continue;
 285		}
 286		if (gh->gh_list.prev == &gl->gl_holders)
 287			return 1;
 288		do_error(gl, 0);
 289		break;
 
 290	}
 291	return 0;
 292}
 293
 294/**
 295 * find_first_waiter - find the first gh that's waiting for the glock
 296 * @gl: the glock
 297 */
 298
 299static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
 300{
 301	struct gfs2_holder *gh;
 302
 303	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
 304		if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
 305			return gh;
 306	}
 307	return NULL;
 308}
 309
 310/**
 311 * state_change - record that the glock is now in a different state
 312 * @gl: the glock
 313 * @new_state the new state
 314 *
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 315 */
 316
 317static void state_change(struct gfs2_glock *gl, unsigned int new_state)
 318{
 319	int held1, held2;
 320
 321	held1 = (gl->gl_state != LM_ST_UNLOCKED);
 322	held2 = (new_state != LM_ST_UNLOCKED);
 323
 324	if (held1 != held2) {
 325		GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
 326		if (held2)
 327			gl->gl_lockref.count++;
 328		else
 329			gl->gl_lockref.count--;
 330	}
 331	if (held1 && held2 && list_empty(&gl->gl_holders))
 332		clear_bit(GLF_QUEUED, &gl->gl_flags);
 333
 334	if (new_state != gl->gl_target)
 335		/* shorten our minimum hold time */
 336		gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
 337				       GL_GLOCK_MIN_HOLD);
 338	gl->gl_state = new_state;
 339	gl->gl_tchange = jiffies;
 340}
 341
 
 
 
 
 
 
 
 
 
 342static void gfs2_demote_wake(struct gfs2_glock *gl)
 343{
 344	gl->gl_demote_state = LM_ST_EXCLUSIVE;
 345	clear_bit(GLF_DEMOTE, &gl->gl_flags);
 346	smp_mb__after_atomic();
 347	wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
 348}
 349
 350/**
 351 * finish_xmote - The DLM has replied to one of our lock requests
 352 * @gl: The glock
 353 * @ret: The status from the DLM
 354 *
 355 */
 356
 357static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
 358{
 359	const struct gfs2_glock_operations *glops = gl->gl_ops;
 360	struct gfs2_holder *gh;
 361	unsigned state = ret & LM_OUT_ST_MASK;
 362	int rv;
 363
 364	spin_lock(&gl->gl_lockref.lock);
 365	trace_gfs2_glock_state_change(gl, state);
 366	state_change(gl, state);
 367	gh = find_first_waiter(gl);
 368
 369	/* Demote to UN request arrived during demote to SH or DF */
 370	if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
 371	    state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
 372		gl->gl_target = LM_ST_UNLOCKED;
 373
 374	/* Check for state != intended state */
 375	if (unlikely(state != gl->gl_target)) {
 
 
 376		if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
 377			/* move to back of queue and try next entry */
 378			if (ret & LM_OUT_CANCELED) {
 379				if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
 380					list_move_tail(&gh->gh_list, &gl->gl_holders);
 381				gh = find_first_waiter(gl);
 382				gl->gl_target = gh->gh_state;
 
 
 383				goto retry;
 384			}
 385			/* Some error or failed "try lock" - report it */
 386			if ((ret & LM_OUT_ERROR) ||
 387			    (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
 388				gl->gl_target = gl->gl_state;
 389				do_error(gl, ret);
 390				goto out;
 391			}
 392		}
 393		switch(state) {
 394		/* Unlocked due to conversion deadlock, try again */
 395		case LM_ST_UNLOCKED:
 396retry:
 397			do_xmote(gl, gh, gl->gl_target);
 398			break;
 399		/* Conversion fails, unlock and try again */
 400		case LM_ST_SHARED:
 401		case LM_ST_DEFERRED:
 402			do_xmote(gl, gh, LM_ST_UNLOCKED);
 403			break;
 404		default: /* Everything else */
 405			pr_err("wanted %u got %u\n", gl->gl_target, state);
 
 406			GLOCK_BUG_ON(gl, 1);
 407		}
 408		spin_unlock(&gl->gl_lockref.lock);
 409		return;
 410	}
 411
 412	/* Fast path - we got what we asked for */
 413	if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
 414		gfs2_demote_wake(gl);
 415	if (state != LM_ST_UNLOCKED) {
 416		if (glops->go_xmote_bh) {
 
 
 417			spin_unlock(&gl->gl_lockref.lock);
 418			rv = glops->go_xmote_bh(gl, gh);
 419			spin_lock(&gl->gl_lockref.lock);
 420			if (rv) {
 421				do_error(gl, rv);
 422				goto out;
 423			}
 424		}
 425		rv = do_promote(gl);
 426		if (rv == 2)
 427			goto out_locked;
 428	}
 429out:
 430	clear_bit(GLF_LOCK, &gl->gl_flags);
 431out_locked:
 432	spin_unlock(&gl->gl_lockref.lock);
 
 
 
 
 
 
 
 
 433}
 434
 435/**
 436 * do_xmote - Calls the DLM to change the state of a lock
 437 * @gl: The lock state
 438 * @gh: The holder (only for promotes)
 439 * @target: The target lock state
 440 *
 441 */
 442
 443static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
 
 444__releases(&gl->gl_lockref.lock)
 445__acquires(&gl->gl_lockref.lock)
 446{
 447	const struct gfs2_glock_operations *glops = gl->gl_ops;
 448	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 
 449	unsigned int lck_flags = (unsigned int)(gh ? gh->gh_flags : 0);
 450	int ret;
 451
 452	lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
 453		      LM_FLAG_PRIORITY);
 
 
 
 454	GLOCK_BUG_ON(gl, gl->gl_state == target);
 455	GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
 456	if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
 457	    glops->go_inval) {
 458		set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
 
 
 
 
 
 
 
 459		do_error(gl, 0); /* Fail queued try locks */
 460	}
 461	gl->gl_req = target;
 462	set_bit(GLF_BLOCKING, &gl->gl_flags);
 463	if ((gl->gl_req == LM_ST_UNLOCKED) ||
 464	    (gl->gl_state == LM_ST_EXCLUSIVE) ||
 465	    (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
 466		clear_bit(GLF_BLOCKING, &gl->gl_flags);
 467	spin_unlock(&gl->gl_lockref.lock);
 468	if (glops->go_sync)
 469		glops->go_sync(gl);
 470	if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
 471		glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
 472	clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
 473
 474	gfs2_glock_hold(gl);
 475	if (sdp->sd_lockstruct.ls_ops->lm_lock)	{
 476		/* lock_dlm */
 477		ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
 
 
 
 478		if (ret) {
 479			pr_err("lm_lock ret %d\n", ret);
 480			GLOCK_BUG_ON(gl, 1);
 
 
 
 
 481		}
 482	} else { /* lock_nolock */
 483		finish_xmote(gl, target);
 484		if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
 485			gfs2_glock_put(gl);
 486	}
 487
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 488	spin_lock(&gl->gl_lockref.lock);
 489}
 490
 491/**
 492 * find_first_holder - find the first "holder" gh
 493 * @gl: the glock
 494 */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 495
 496static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
 497{
 498	struct gfs2_holder *gh;
 
 499
 500	if (!list_empty(&gl->gl_holders)) {
 501		gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
 502		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
 503			return gh;
 
 
 
 
 
 
 
 
 
 
 504	}
 505	return NULL;
 
 
 
 506}
 507
 508/**
 509 * run_queue - do all outstanding tasks related to a glock
 510 * @gl: The glock in question
 511 * @nonblock: True if we must not block in run_queue
 512 *
 513 */
 514
 515static void run_queue(struct gfs2_glock *gl, const int nonblock)
 516__releases(&gl->gl_lockref.lock)
 517__acquires(&gl->gl_lockref.lock)
 518{
 519	struct gfs2_holder *gh = NULL;
 520	int ret;
 521
 522	if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
 523		return;
 524
 525	GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));
 526
 527	if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
 528	    gl->gl_demote_state != gl->gl_state) {
 529		if (find_first_holder(gl))
 530			goto out_unlock;
 531		if (nonblock)
 532			goto out_sched;
 533		set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
 534		GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
 535		gl->gl_target = gl->gl_demote_state;
 536	} else {
 537		if (test_bit(GLF_DEMOTE, &gl->gl_flags))
 538			gfs2_demote_wake(gl);
 539		ret = do_promote(gl);
 540		if (ret == 0)
 541			goto out_unlock;
 542		if (ret == 2)
 543			goto out;
 544		gh = find_first_waiter(gl);
 545		gl->gl_target = gh->gh_state;
 546		if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
 547			do_error(gl, 0); /* Fail queued try locks */
 548	}
 549	do_xmote(gl, gh, gl->gl_target);
 550out:
 551	return;
 552
 553out_sched:
 554	clear_bit(GLF_LOCK, &gl->gl_flags);
 555	smp_mb__after_atomic();
 556	gl->gl_lockref.count++;
 557	if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
 558		gl->gl_lockref.count--;
 559	return;
 560
 561out_unlock:
 562	clear_bit(GLF_LOCK, &gl->gl_flags);
 563	smp_mb__after_atomic();
 564	return;
 565}
 566
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 567static void delete_work_func(struct work_struct *work)
 568{
 569	struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
 
 570	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 571	struct gfs2_inode *ip;
 572	struct inode *inode;
 573	u64 no_addr = gl->gl_name.ln_number;
 574
 575	/* If someone's using this glock to create a new dinode, the block must
 576	   have been freed by another node, then re-used, in which case our
 577	   iopen callback is too late after the fact. Ignore it. */
 578	if (test_bit(GLF_INODE_CREATING, &gl->gl_flags))
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 579		goto out;
 
 580
 581	ip = gl->gl_object;
 582	/* Note: Unsafe to dereference ip as we don't hold right refs/locks */
 583
 584	if (ip)
 585		inode = gfs2_ilookup(sdp->sd_vfs, no_addr);
 586	else
 587		inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
 588	if (inode && !IS_ERR(inode)) {
 589		d_prune_aliases(inode);
 590		iput(inode);
 
 
 591	}
 
 592out:
 593	gfs2_glock_put(gl);
 594}
 595
 596static 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
 648int 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	gl = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
 662	if (gl && !lockref_get_not_dead(&gl->gl_lockref))
 663		gl = NULL;
 664
 665	*glp = gl;
 666	if (gl)
 
 667		return 0;
 
 668	if (!create)
 669		return -ENOENT;
 670
 671	if (glops->go_flags & GLOF_ASPACE)
 672		cachep = gfs2_glock_aspace_cachep;
 673	else
 674		cachep = gfs2_glock_cachep;
 675	gl = kmem_cache_alloc(cachep, GFP_NOFS);
 676	if (!gl)
 677		return -ENOMEM;
 678
 
 
 
 679	memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));
 
 680
 681	if (glops->go_flags & GLOF_LVB) {
 682		gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_NOFS);
 683		if (!gl->gl_lksb.sb_lvbptr) {
 684			kmem_cache_free(cachep, gl);
 685			return -ENOMEM;
 686		}
 687	}
 688
 689	atomic_inc(&sdp->sd_glock_disposal);
 690	gl->gl_node.next = NULL;
 691	gl->gl_flags = 0;
 692	gl->gl_name = name;
 
 693	gl->gl_lockref.count = 1;
 694	gl->gl_state = LM_ST_UNLOCKED;
 695	gl->gl_target = LM_ST_UNLOCKED;
 696	gl->gl_demote_state = LM_ST_EXCLUSIVE;
 697	gl->gl_ops = glops;
 698	gl->gl_dstamp = ktime_set(0, 0);
 699	preempt_disable();
 700	/* We use the global stats to estimate the initial per-glock stats */
 701	gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
 702	preempt_enable();
 703	gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
 704	gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
 705	gl->gl_tchange = jiffies;
 706	gl->gl_object = NULL;
 707	gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
 708	INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
 709	INIT_WORK(&gl->gl_delete, delete_work_func);
 
 710
 711	mapping = gfs2_glock2aspace(gl);
 712	if (mapping) {
 713                mapping->a_ops = &gfs2_meta_aops;
 714		mapping->host = s->s_bdev->bd_inode;
 715		mapping->flags = 0;
 716		mapping_set_gfp_mask(mapping, GFP_NOFS);
 717		mapping->private_data = NULL;
 718		mapping->writeback_index = 0;
 719	}
 720
 721again:
 722	ret = rhashtable_lookup_insert_fast(&gl_hash_table, &gl->gl_node,
 723					    ht_parms);
 724	if (ret == 0) {
 725		*glp = gl;
 726		return 0;
 727	}
 728
 729	if (ret == -EEXIST) {
 730		ret = 0;
 731		tmp = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
 732		if (tmp == NULL || !lockref_get_not_dead(&tmp->gl_lockref)) {
 733			if (++tries < 100) {
 734				cond_resched();
 735				goto again;
 736			}
 737			tmp = NULL;
 738			ret = -ENOMEM;
 739		}
 740	} else {
 741		WARN_ON_ONCE(ret);
 742	}
 743	kfree(gl->gl_lksb.sb_lvbptr);
 744	kmem_cache_free(cachep, gl);
 745	atomic_dec(&sdp->sd_glock_disposal);
 746	*glp = tmp;
 747
 
 
 
 
 
 
 748	return ret;
 749}
 750
 751/**
 752 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
 753 * @gl: the glock
 754 * @state: the state we're requesting
 755 * @flags: the modifier flags
 756 * @gh: the holder structure
 757 *
 758 */
 759
 760void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, u16 flags,
 761		      struct gfs2_holder *gh)
 762{
 763	INIT_LIST_HEAD(&gh->gh_list);
 764	gh->gh_gl = gl;
 765	gh->gh_ip = _RET_IP_;
 766	gh->gh_owner_pid = get_pid(task_pid(current));
 767	gh->gh_state = state;
 768	gh->gh_flags = flags;
 769	gh->gh_error = 0;
 770	gh->gh_iflags = 0;
 771	gfs2_glock_hold(gl);
 772}
 773
 774/**
 775 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
 776 * @state: the state we're requesting
 777 * @flags: the modifier flags
 778 * @gh: the holder structure
 779 *
 780 * Don't mess with the glock.
 781 *
 782 */
 783
 784void gfs2_holder_reinit(unsigned int state, u16 flags, struct gfs2_holder *gh)
 785{
 786	gh->gh_state = state;
 787	gh->gh_flags = flags;
 788	gh->gh_iflags = 0;
 789	gh->gh_ip = _RET_IP_;
 790	put_pid(gh->gh_owner_pid);
 791	gh->gh_owner_pid = get_pid(task_pid(current));
 792}
 793
 794/**
 795 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
 796 * @gh: the holder structure
 797 *
 798 */
 799
 800void gfs2_holder_uninit(struct gfs2_holder *gh)
 801{
 802	put_pid(gh->gh_owner_pid);
 803	gfs2_glock_put(gh->gh_gl);
 804	gh->gh_gl = NULL;
 805	gh->gh_ip = 0;
 806}
 807
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 808/**
 809 * gfs2_glock_wait - wait on a glock acquisition
 810 * @gh: the glock holder
 811 *
 812 * Returns: 0 on success
 813 */
 814
 815int gfs2_glock_wait(struct gfs2_holder *gh)
 816{
 817	unsigned long time1 = jiffies;
 818
 819	might_sleep();
 820	wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE);
 821	if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
 822		/* Lengthen the minimum hold time. */
 823		gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
 824					      GL_GLOCK_HOLD_INCR,
 825					      GL_GLOCK_MAX_HOLD);
 826	return gh->gh_error;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 827}
 828
 829/**
 830 * handle_callback - process a demote request
 831 * @gl: the glock
 832 * @state: the state the caller wants us to change to
 
 
 833 *
 834 * There are only two requests that we are going to see in actual
 835 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
 836 */
 837
 838static void handle_callback(struct gfs2_glock *gl, unsigned int state,
 839			    unsigned long delay, bool remote)
 840{
 841	int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
 842
 843	set_bit(bit, &gl->gl_flags);
 
 844	if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
 845		gl->gl_demote_state = state;
 846		gl->gl_demote_time = jiffies;
 847	} else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
 848			gl->gl_demote_state != state) {
 849		gl->gl_demote_state = LM_ST_UNLOCKED;
 850	}
 851	if (gl->gl_ops->go_callback)
 852		gl->gl_ops->go_callback(gl, remote);
 853	trace_gfs2_demote_rq(gl, remote);
 854}
 855
 856void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
 857{
 858	struct va_format vaf;
 859	va_list args;
 860
 861	va_start(args, fmt);
 862
 863	if (seq) {
 864		seq_vprintf(seq, fmt, args);
 865	} else {
 866		vaf.fmt = fmt;
 867		vaf.va = &args;
 868
 869		pr_err("%pV", &vaf);
 870	}
 871
 872	va_end(args);
 873}
 874
 
 
 
 
 
 
 
 
 
 875/**
 876 * add_to_queue - Add a holder to the wait queue (but look for recursion)
 877 * @gh: the holder structure to add
 878 *
 879 * Eventually we should move the recursive locking trap to a
 880 * debugging option or something like that. This is the fast
 881 * path and needs to have the minimum number of distractions.
 882 * 
 883 */
 884
 885static inline void add_to_queue(struct gfs2_holder *gh)
 886__releases(&gl->gl_lockref.lock)
 887__acquires(&gl->gl_lockref.lock)
 888{
 889	struct gfs2_glock *gl = gh->gh_gl;
 890	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 891	struct list_head *insert_pt = NULL;
 892	struct gfs2_holder *gh2;
 893	int try_futile = 0;
 894
 895	BUG_ON(gh->gh_owner_pid == NULL);
 896	if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
 897		BUG();
 898
 899	if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
 900		if (test_bit(GLF_LOCK, &gl->gl_flags))
 901			try_futile = !may_grant(gl, gh);
 
 
 
 
 902		if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
 903			goto fail;
 904	}
 905
 906	list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
 907		if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
 908		    (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
 909			goto trap_recursive;
 
 
 
 
 
 
 910		if (try_futile &&
 911		    !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
 912fail:
 913			gh->gh_error = GLR_TRYFAILED;
 914			gfs2_holder_wake(gh);
 915			return;
 916		}
 917		if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
 918			continue;
 919		if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
 920			insert_pt = &gh2->gh_list;
 921	}
 922	set_bit(GLF_QUEUED, &gl->gl_flags);
 923	trace_gfs2_glock_queue(gh, 1);
 924	gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
 925	gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
 926	if (likely(insert_pt == NULL)) {
 927		list_add_tail(&gh->gh_list, &gl->gl_holders);
 928		if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
 929			goto do_cancel;
 930		return;
 931	}
 932	list_add_tail(&gh->gh_list, insert_pt);
 933do_cancel:
 934	gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
 935	if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
 936		spin_unlock(&gl->gl_lockref.lock);
 937		if (sdp->sd_lockstruct.ls_ops->lm_cancel)
 938			sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
 939		spin_lock(&gl->gl_lockref.lock);
 940	}
 941	return;
 942
 943trap_recursive:
 944	pr_err("original: %pSR\n", (void *)gh2->gh_ip);
 945	pr_err("pid: %d\n", pid_nr(gh2->gh_owner_pid));
 946	pr_err("lock type: %d req lock state : %d\n",
 947	       gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
 948	pr_err("new: %pSR\n", (void *)gh->gh_ip);
 949	pr_err("pid: %d\n", pid_nr(gh->gh_owner_pid));
 950	pr_err("lock type: %d req lock state : %d\n",
 951	       gh->gh_gl->gl_name.ln_type, gh->gh_state);
 952	gfs2_dump_glock(NULL, gl);
 953	BUG();
 954}
 955
 956/**
 957 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
 958 * @gh: the holder structure
 959 *
 960 * if (gh->gh_flags & GL_ASYNC), this never returns an error
 961 *
 962 * Returns: 0, GLR_TRYFAILED, or errno on failure
 963 */
 964
 965int gfs2_glock_nq(struct gfs2_holder *gh)
 966{
 967	struct gfs2_glock *gl = gh->gh_gl;
 968	struct gfs2_sbd *sdp = gl->gl_name.ln_sbd;
 969	int error = 0;
 970
 971	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
 972		return -EIO;
 973
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 974	if (test_bit(GLF_LRU, &gl->gl_flags))
 975		gfs2_glock_remove_from_lru(gl);
 976
 
 977	spin_lock(&gl->gl_lockref.lock);
 978	add_to_queue(gh);
 979	if (unlikely((LM_FLAG_NOEXP & gh->gh_flags) &&
 980		     test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))) {
 981		set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
 982		gl->gl_lockref.count++;
 983		if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
 984			gl->gl_lockref.count--;
 985	}
 986	run_queue(gl, 1);
 987	spin_unlock(&gl->gl_lockref.lock);
 988
 
 989	if (!(gh->gh_flags & GL_ASYNC))
 990		error = gfs2_glock_wait(gh);
 991
 992	return error;
 993}
 994
 995/**
 996 * gfs2_glock_poll - poll to see if an async request has been completed
 997 * @gh: the holder
 998 *
 999 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
1000 */
1001
1002int gfs2_glock_poll(struct gfs2_holder *gh)
1003{
1004	return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
1005}
1006
1007/**
1008 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
1009 * @gh: the glock holder
1010 *
1011 */
1012
1013void gfs2_glock_dq(struct gfs2_holder *gh)
1014{
1015	struct gfs2_glock *gl = gh->gh_gl;
1016	const struct gfs2_glock_operations *glops = gl->gl_ops;
1017	unsigned delay = 0;
1018	int fast_path = 0;
1019
1020	spin_lock(&gl->gl_lockref.lock);
 
 
 
 
1021	if (gh->gh_flags & GL_NOCACHE)
1022		handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1023
1024	list_del_init(&gh->gh_list);
1025	clear_bit(HIF_HOLDER, &gh->gh_iflags);
1026	if (find_first_holder(gl) == NULL) {
1027		if (glops->go_unlock) {
1028			GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1029			spin_unlock(&gl->gl_lockref.lock);
1030			glops->go_unlock(gh);
1031			spin_lock(&gl->gl_lockref.lock);
1032			clear_bit(GLF_LOCK, &gl->gl_flags);
1033		}
1034		if (list_empty(&gl->gl_holders) &&
1035		    !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1036		    !test_bit(GLF_DEMOTE, &gl->gl_flags))
1037			fast_path = 1;
1038	}
1039	if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl) &&
1040	    (glops->go_flags & GLOF_LRU))
1041		gfs2_glock_add_to_lru(gl);
1042
1043	trace_gfs2_glock_queue(gh, 0);
1044	spin_unlock(&gl->gl_lockref.lock);
1045	if (likely(fast_path))
1046		return;
 
 
 
 
 
1047
1048	gfs2_glock_hold(gl);
1049	if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1050	    !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
1051	    gl->gl_name.ln_type == LM_TYPE_INODE)
1052		delay = gl->gl_hold_time;
1053	if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1054		gfs2_glock_put(gl);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1055}
1056
1057void gfs2_glock_dq_wait(struct gfs2_holder *gh)
1058{
1059	struct gfs2_glock *gl = gh->gh_gl;
1060	gfs2_glock_dq(gh);
1061	might_sleep();
1062	wait_on_bit(&gl->gl_flags, GLF_DEMOTE, TASK_UNINTERRUPTIBLE);
1063}
1064
1065/**
1066 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
1067 * @gh: the holder structure
1068 *
1069 */
1070
1071void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
1072{
1073	gfs2_glock_dq(gh);
1074	gfs2_holder_uninit(gh);
1075}
1076
1077/**
1078 * gfs2_glock_nq_num - acquire a glock based on lock number
1079 * @sdp: the filesystem
1080 * @number: the lock number
1081 * @glops: the glock operations for the type of glock
1082 * @state: the state to acquire the glock in
1083 * @flags: modifier flags for the acquisition
1084 * @gh: the struct gfs2_holder
1085 *
1086 * Returns: errno
1087 */
1088
1089int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1090		      const struct gfs2_glock_operations *glops,
1091		      unsigned int state, u16 flags, struct gfs2_holder *gh)
1092{
1093	struct gfs2_glock *gl;
1094	int error;
1095
1096	error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
1097	if (!error) {
1098		error = gfs2_glock_nq_init(gl, state, flags, gh);
1099		gfs2_glock_put(gl);
1100	}
1101
1102	return error;
1103}
1104
1105/**
1106 * glock_compare - Compare two struct gfs2_glock structures for sorting
1107 * @arg_a: the first structure
1108 * @arg_b: the second structure
1109 *
1110 */
1111
1112static int glock_compare(const void *arg_a, const void *arg_b)
1113{
1114	const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
1115	const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
1116	const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
1117	const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
1118
1119	if (a->ln_number > b->ln_number)
1120		return 1;
1121	if (a->ln_number < b->ln_number)
1122		return -1;
1123	BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1124	return 0;
1125}
1126
1127/**
1128 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
1129 * @num_gh: the number of structures
1130 * @ghs: an array of struct gfs2_holder structures
 
1131 *
1132 * Returns: 0 on success (all glocks acquired),
1133 *          errno on failure (no glocks acquired)
1134 */
1135
1136static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
1137		     struct gfs2_holder **p)
1138{
1139	unsigned int x;
1140	int error = 0;
1141
1142	for (x = 0; x < num_gh; x++)
1143		p[x] = &ghs[x];
1144
1145	sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);
1146
1147	for (x = 0; x < num_gh; x++) {
1148		p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1149
1150		error = gfs2_glock_nq(p[x]);
1151		if (error) {
1152			while (x--)
1153				gfs2_glock_dq(p[x]);
1154			break;
1155		}
1156	}
1157
1158	return error;
1159}
1160
1161/**
1162 * gfs2_glock_nq_m - acquire multiple glocks
1163 * @num_gh: the number of structures
1164 * @ghs: an array of struct gfs2_holder structures
1165 *
1166 *
1167 * Returns: 0 on success (all glocks acquired),
1168 *          errno on failure (no glocks acquired)
1169 */
1170
1171int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1172{
1173	struct gfs2_holder *tmp[4];
1174	struct gfs2_holder **pph = tmp;
1175	int error = 0;
1176
1177	switch(num_gh) {
1178	case 0:
1179		return 0;
1180	case 1:
1181		ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
1182		return gfs2_glock_nq(ghs);
1183	default:
1184		if (num_gh <= 4)
1185			break;
1186		pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
 
1187		if (!pph)
1188			return -ENOMEM;
1189	}
1190
1191	error = nq_m_sync(num_gh, ghs, pph);
1192
1193	if (pph != tmp)
1194		kfree(pph);
1195
1196	return error;
1197}
1198
1199/**
1200 * gfs2_glock_dq_m - release multiple glocks
1201 * @num_gh: the number of structures
1202 * @ghs: an array of struct gfs2_holder structures
1203 *
1204 */
1205
1206void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
1207{
1208	while (num_gh--)
1209		gfs2_glock_dq(&ghs[num_gh]);
1210}
1211
1212void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1213{
1214	unsigned long delay = 0;
1215	unsigned long holdtime;
1216	unsigned long now = jiffies;
1217
1218	gfs2_glock_hold(gl);
 
1219	holdtime = gl->gl_tchange + gl->gl_hold_time;
1220	if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
1221	    gl->gl_name.ln_type == LM_TYPE_INODE) {
1222		if (time_before(now, holdtime))
1223			delay = holdtime - now;
1224		if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1225			delay = gl->gl_hold_time;
1226	}
1227
1228	spin_lock(&gl->gl_lockref.lock);
1229	handle_callback(gl, state, delay, true);
 
1230	spin_unlock(&gl->gl_lockref.lock);
1231	if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
1232		gfs2_glock_put(gl);
1233}
1234
1235/**
1236 * gfs2_should_freeze - Figure out if glock should be frozen
1237 * @gl: The glock in question
1238 *
1239 * Glocks are not frozen if (a) the result of the dlm operation is
1240 * an error, (b) the locking operation was an unlock operation or
1241 * (c) if there is a "noexp" flagged request anywhere in the queue
1242 *
1243 * Returns: 1 if freezing should occur, 0 otherwise
1244 */
1245
1246static int gfs2_should_freeze(const struct gfs2_glock *gl)
1247{
1248	const struct gfs2_holder *gh;
1249
1250	if (gl->gl_reply & ~LM_OUT_ST_MASK)
1251		return 0;
1252	if (gl->gl_target == LM_ST_UNLOCKED)
1253		return 0;
1254
1255	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1256		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
1257			continue;
1258		if (LM_FLAG_NOEXP & gh->gh_flags)
1259			return 0;
1260	}
1261
1262	return 1;
1263}
1264
1265/**
1266 * gfs2_glock_complete - Callback used by locking
1267 * @gl: Pointer to the glock
1268 * @ret: The return value from the dlm
1269 *
1270 * The gl_reply field is under the gl_lockref.lock lock so that it is ok
1271 * to use a bitfield shared with other glock state fields.
1272 */
1273
1274void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
1275{
1276	struct lm_lockstruct *ls = &gl->gl_name.ln_sbd->sd_lockstruct;
1277
1278	spin_lock(&gl->gl_lockref.lock);
1279	gl->gl_reply = ret;
1280
1281	if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1282		if (gfs2_should_freeze(gl)) {
1283			set_bit(GLF_FROZEN, &gl->gl_flags);
1284			spin_unlock(&gl->gl_lockref.lock);
1285			return;
1286		}
1287	}
1288
1289	gl->gl_lockref.count++;
1290	set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
 
1291	spin_unlock(&gl->gl_lockref.lock);
1292
1293	if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1294		gfs2_glock_put(gl);
1295}
1296
1297static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
 
1298{
1299	struct gfs2_glock *gla, *glb;
1300
1301	gla = list_entry(a, struct gfs2_glock, gl_lru);
1302	glb = list_entry(b, struct gfs2_glock, gl_lru);
1303
1304	if (gla->gl_name.ln_number > glb->gl_name.ln_number)
1305		return 1;
1306	if (gla->gl_name.ln_number < glb->gl_name.ln_number)
1307		return -1;
1308
1309	return 0;
1310}
1311
1312/**
1313 * gfs2_dispose_glock_lru - Demote a list of glocks
1314 * @list: The list to dispose of
1315 *
1316 * Disposing of glocks may involve disk accesses, so that here we sort
1317 * the glocks by number (i.e. disk location of the inodes) so that if
1318 * there are any such accesses, they'll be sent in order (mostly).
1319 *
1320 * Must be called under the lru_lock, but may drop and retake this
1321 * lock. While the lru_lock is dropped, entries may vanish from the
1322 * list, but no new entries will appear on the list (since it is
1323 * private)
1324 */
1325
1326static void gfs2_dispose_glock_lru(struct list_head *list)
1327__releases(&lru_lock)
1328__acquires(&lru_lock)
1329{
1330	struct gfs2_glock *gl;
1331
1332	list_sort(NULL, list, glock_cmp);
1333
1334	while(!list_empty(list)) {
1335		gl = list_entry(list->next, struct gfs2_glock, gl_lru);
1336		list_del_init(&gl->gl_lru);
 
1337		if (!spin_trylock(&gl->gl_lockref.lock)) {
1338add_back_to_lru:
1339			list_add(&gl->gl_lru, &lru_list);
 
1340			atomic_inc(&lru_count);
1341			continue;
1342		}
1343		if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1344			spin_unlock(&gl->gl_lockref.lock);
1345			goto add_back_to_lru;
1346		}
1347		clear_bit(GLF_LRU, &gl->gl_flags);
1348		gl->gl_lockref.count++;
1349		if (demote_ok(gl))
1350			handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1351		WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
1352		if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1353			gl->gl_lockref.count--;
1354		spin_unlock(&gl->gl_lockref.lock);
1355		cond_resched_lock(&lru_lock);
1356	}
1357}
1358
1359/**
1360 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
1361 * @nr: The number of entries to scan
1362 *
1363 * This function selects the entries on the LRU which are able to
1364 * be demoted, and then kicks off the process by calling
1365 * gfs2_dispose_glock_lru() above.
1366 */
1367
1368static long gfs2_scan_glock_lru(int nr)
1369{
1370	struct gfs2_glock *gl;
1371	LIST_HEAD(skipped);
1372	LIST_HEAD(dispose);
1373	long freed = 0;
1374
1375	spin_lock(&lru_lock);
1376	while ((nr-- >= 0) && !list_empty(&lru_list)) {
1377		gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);
1378
1379		/* Test for being demotable */
1380		if (!test_bit(GLF_LOCK, &gl->gl_flags)) {
1381			list_move(&gl->gl_lru, &dispose);
1382			atomic_dec(&lru_count);
1383			freed++;
1384			continue;
 
 
 
 
 
 
1385		}
1386
1387		list_move(&gl->gl_lru, &skipped);
1388	}
1389	list_splice(&skipped, &lru_list);
1390	if (!list_empty(&dispose))
1391		gfs2_dispose_glock_lru(&dispose);
1392	spin_unlock(&lru_lock);
1393
1394	return freed;
1395}
1396
1397static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
1398					    struct shrink_control *sc)
1399{
1400	if (!(sc->gfp_mask & __GFP_FS))
1401		return SHRINK_STOP;
1402	return gfs2_scan_glock_lru(sc->nr_to_scan);
1403}
1404
1405static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
1406					     struct shrink_control *sc)
1407{
1408	return vfs_pressure_ratio(atomic_read(&lru_count));
1409}
1410
1411static struct shrinker glock_shrinker = {
1412	.seeks = DEFAULT_SEEKS,
1413	.count_objects = gfs2_glock_shrink_count,
1414	.scan_objects = gfs2_glock_shrink_scan,
1415};
1416
1417/**
1418 * examine_bucket - Call a function for glock in a hash bucket
1419 * @examiner: the function
1420 * @sdp: the filesystem
1421 * @bucket: the bucket
1422 *
 
 
 
1423 */
1424
1425static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
1426{
1427	struct gfs2_glock *gl;
1428	struct rhash_head *pos;
1429	const struct bucket_table *tbl;
1430	int i;
1431
1432	rcu_read_lock();
1433	tbl = rht_dereference_rcu(gl_hash_table.tbl, &gl_hash_table);
1434	for (i = 0; i < tbl->size; i++) {
1435		rht_for_each_entry_rcu(gl, pos, tbl, i, gl_node) {
1436			if ((gl->gl_name.ln_sbd == sdp) &&
1437			    lockref_get_not_dead(&gl->gl_lockref))
 
1438				examiner(gl);
1439		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1440	}
1441	rcu_read_unlock();
1442	cond_resched();
 
 
 
 
1443}
1444
1445/**
1446 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
1447 * @gl: The glock to thaw
1448 *
1449 */
1450
1451static void thaw_glock(struct gfs2_glock *gl)
1452{
1453	if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1454		goto out;
 
 
 
 
1455	set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1456	if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) {
1457out:
1458		gfs2_glock_put(gl);
1459	}
1460}
1461
1462/**
1463 * clear_glock - look at a glock and see if we can free it from glock cache
1464 * @gl: the glock to look at
1465 *
1466 */
1467
1468static void clear_glock(struct gfs2_glock *gl)
1469{
1470	gfs2_glock_remove_from_lru(gl);
1471
1472	spin_lock(&gl->gl_lockref.lock);
1473	if (gl->gl_state != LM_ST_UNLOCKED)
1474		handle_callback(gl, LM_ST_UNLOCKED, 0, false);
 
 
 
 
1475	spin_unlock(&gl->gl_lockref.lock);
1476	if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
1477		gfs2_glock_put(gl);
1478}
1479
1480/**
1481 * gfs2_glock_thaw - Thaw any frozen glocks
1482 * @sdp: The super block
1483 *
1484 */
1485
1486void gfs2_glock_thaw(struct gfs2_sbd *sdp)
1487{
1488	glock_hash_walk(thaw_glock, sdp);
1489}
1490
1491static void dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
1492{
1493	spin_lock(&gl->gl_lockref.lock);
1494	gfs2_dump_glock(seq, gl);
1495	spin_unlock(&gl->gl_lockref.lock);
1496}
1497
1498static void dump_glock_func(struct gfs2_glock *gl)
1499{
1500	dump_glock(NULL, gl);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1501}
1502
1503/**
1504 * gfs2_gl_hash_clear - Empty out the glock hash table
1505 * @sdp: the filesystem
1506 * @wait: wait until it's all gone
1507 *
1508 * Called when unmounting the filesystem.
1509 */
1510
1511void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
1512{
1513	set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1514	flush_workqueue(glock_workqueue);
1515	glock_hash_walk(clear_glock, sdp);
1516	flush_workqueue(glock_workqueue);
1517	wait_event_timeout(sdp->sd_glock_wait,
1518			   atomic_read(&sdp->sd_glock_disposal) == 0,
1519			   HZ * 600);
 
 
1520	glock_hash_walk(dump_glock_func, sdp);
1521}
1522
1523void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
1524{
1525	struct gfs2_glock *gl = ip->i_gl;
1526	int ret;
1527
1528	ret = gfs2_truncatei_resume(ip);
1529	gfs2_assert_withdraw(gl->gl_name.ln_sbd, ret == 0);
1530
1531	spin_lock(&gl->gl_lockref.lock);
1532	clear_bit(GLF_LOCK, &gl->gl_flags);
1533	run_queue(gl, 1);
1534	spin_unlock(&gl->gl_lockref.lock);
1535}
1536
1537static const char *state2str(unsigned state)
1538{
1539	switch(state) {
1540	case LM_ST_UNLOCKED:
1541		return "UN";
1542	case LM_ST_SHARED:
1543		return "SH";
1544	case LM_ST_DEFERRED:
1545		return "DF";
1546	case LM_ST_EXCLUSIVE:
1547		return "EX";
1548	}
1549	return "??";
1550}
1551
1552static const char *hflags2str(char *buf, u16 flags, unsigned long iflags)
1553{
1554	char *p = buf;
1555	if (flags & LM_FLAG_TRY)
1556		*p++ = 't';
1557	if (flags & LM_FLAG_TRY_1CB)
1558		*p++ = 'T';
1559	if (flags & LM_FLAG_NOEXP)
1560		*p++ = 'e';
1561	if (flags & LM_FLAG_ANY)
1562		*p++ = 'A';
1563	if (flags & LM_FLAG_PRIORITY)
1564		*p++ = 'p';
1565	if (flags & GL_ASYNC)
1566		*p++ = 'a';
1567	if (flags & GL_EXACT)
1568		*p++ = 'E';
1569	if (flags & GL_NOCACHE)
1570		*p++ = 'c';
1571	if (test_bit(HIF_HOLDER, &iflags))
1572		*p++ = 'H';
1573	if (test_bit(HIF_WAIT, &iflags))
1574		*p++ = 'W';
1575	if (test_bit(HIF_FIRST, &iflags))
1576		*p++ = 'F';
1577	*p = 0;
1578	return buf;
1579}
1580
1581/**
1582 * dump_holder - print information about a glock holder
1583 * @seq: the seq_file struct
1584 * @gh: the glock holder
 
1585 *
1586 */
1587
1588static void dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
 
1589{
1590	struct task_struct *gh_owner = NULL;
 
1591	char flags_buf[32];
1592
1593	rcu_read_lock();
1594	if (gh->gh_owner_pid)
 
 
 
 
1595		gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1596	gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
1597		       state2str(gh->gh_state),
 
 
 
1598		       hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
1599		       gh->gh_error,
1600		       gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
1601		       gh_owner ? gh_owner->comm : "(ended)",
1602		       (void *)gh->gh_ip);
1603	rcu_read_unlock();
1604}
1605
1606static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1607{
1608	const unsigned long *gflags = &gl->gl_flags;
1609	char *p = buf;
1610
1611	if (test_bit(GLF_LOCK, gflags))
1612		*p++ = 'l';
1613	if (test_bit(GLF_DEMOTE, gflags))
1614		*p++ = 'D';
1615	if (test_bit(GLF_PENDING_DEMOTE, gflags))
1616		*p++ = 'd';
1617	if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
1618		*p++ = 'p';
1619	if (test_bit(GLF_DIRTY, gflags))
1620		*p++ = 'y';
1621	if (test_bit(GLF_LFLUSH, gflags))
1622		*p++ = 'f';
1623	if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
1624		*p++ = 'i';
1625	if (test_bit(GLF_REPLY_PENDING, gflags))
1626		*p++ = 'r';
1627	if (test_bit(GLF_INITIAL, gflags))
1628		*p++ = 'I';
1629	if (test_bit(GLF_FROZEN, gflags))
1630		*p++ = 'F';
1631	if (test_bit(GLF_QUEUED, gflags))
1632		*p++ = 'q';
1633	if (test_bit(GLF_LRU, gflags))
1634		*p++ = 'L';
1635	if (gl->gl_object)
1636		*p++ = 'o';
1637	if (test_bit(GLF_BLOCKING, gflags))
1638		*p++ = 'b';
 
 
 
 
 
 
 
 
 
 
1639	*p = 0;
1640	return buf;
1641}
1642
1643/**
1644 * gfs2_dump_glock - print information about a glock
1645 * @seq: The seq_file struct
1646 * @gl: the glock
 
1647 *
1648 * The file format is as follows:
1649 * One line per object, capital letters are used to indicate objects
1650 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
1651 * other objects are indented by a single space and follow the glock to
1652 * which they are related. Fields are indicated by lower case letters
1653 * followed by a colon and the field value, except for strings which are in
1654 * [] so that its possible to see if they are composed of spaces for
1655 * example. The field's are n = number (id of the object), f = flags,
1656 * t = type, s = state, r = refcount, e = error, p = pid.
1657 *
1658 */
1659
1660void gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
1661{
1662	const struct gfs2_glock_operations *glops = gl->gl_ops;
1663	unsigned long long dtime;
1664	const struct gfs2_holder *gh;
1665	char gflags_buf[32];
 
 
 
 
 
 
1666
 
 
 
 
 
1667	dtime = jiffies - gl->gl_demote_time;
1668	dtime *= 1000000/HZ; /* demote time in uSec */
1669	if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
1670		dtime = 0;
1671	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",
1672		  state2str(gl->gl_state),
1673		  gl->gl_name.ln_type,
1674		  (unsigned long long)gl->gl_name.ln_number,
1675		  gflags2str(gflags_buf, gl),
1676		  state2str(gl->gl_target),
1677		  state2str(gl->gl_demote_state), dtime,
1678		  atomic_read(&gl->gl_ail_count),
1679		  atomic_read(&gl->gl_revokes),
1680		  (int)gl->gl_lockref.count, gl->gl_hold_time);
 
1681
1682	list_for_each_entry(gh, &gl->gl_holders, gh_list)
1683		dump_holder(seq, gh);
1684
1685	if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
1686		glops->go_dump(seq, gl);
1687}
1688
1689static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
1690{
1691	struct gfs2_glock *gl = iter_ptr;
1692
1693	seq_printf(seq, "G: n:%u/%llx rtt:%llu/%llu rttb:%llu/%llu irt:%llu/%llu dcnt: %llu qcnt: %llu\n",
1694		   gl->gl_name.ln_type,
1695		   (unsigned long long)gl->gl_name.ln_number,
1696		   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
1697		   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
1698		   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
1699		   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
1700		   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
1701		   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
1702		   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
1703		   (unsigned long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
1704	return 0;
1705}
1706
1707static const char *gfs2_gltype[] = {
1708	"type",
1709	"reserved",
1710	"nondisk",
1711	"inode",
1712	"rgrp",
1713	"meta",
1714	"iopen",
1715	"flock",
1716	"plock",
1717	"quota",
1718	"journal",
1719};
1720
1721static const char *gfs2_stype[] = {
1722	[GFS2_LKS_SRTT]		= "srtt",
1723	[GFS2_LKS_SRTTVAR]	= "srttvar",
1724	[GFS2_LKS_SRTTB]	= "srttb",
1725	[GFS2_LKS_SRTTVARB]	= "srttvarb",
1726	[GFS2_LKS_SIRT]		= "sirt",
1727	[GFS2_LKS_SIRTVAR]	= "sirtvar",
1728	[GFS2_LKS_DCOUNT]	= "dlm",
1729	[GFS2_LKS_QCOUNT]	= "queue",
1730};
1731
1732#define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))
1733
1734static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
1735{
1736	struct gfs2_sbd *sdp = seq->private;
1737	loff_t pos = *(loff_t *)iter_ptr;
1738	unsigned index = pos >> 3;
1739	unsigned subindex = pos & 0x07;
1740	int i;
1741
1742	if (index == 0 && subindex != 0)
1743		return 0;
1744
1745	seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
1746		   (index == 0) ? "cpu": gfs2_stype[subindex]);
1747
1748	for_each_possible_cpu(i) {
1749                const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
1750
1751		if (index == 0)
1752			seq_printf(seq, " %15u", i);
1753		else
1754			seq_printf(seq, " %15llu", (unsigned long long)lkstats->
1755				   lkstats[index - 1].stats[subindex]);
1756	}
1757	seq_putc(seq, '\n');
1758	return 0;
1759}
1760
1761int __init gfs2_glock_init(void)
1762{
1763	int ret;
1764
1765	ret = rhashtable_init(&gl_hash_table, &ht_parms);
1766	if (ret < 0)
1767		return ret;
1768
1769	glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1770					  WQ_HIGHPRI | WQ_FREEZABLE, 0);
1771	if (!glock_workqueue) {
1772		rhashtable_destroy(&gl_hash_table);
1773		return -ENOMEM;
1774	}
1775	gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1776						WQ_MEM_RECLAIM | WQ_FREEZABLE,
1777						0);
1778	if (!gfs2_delete_workqueue) {
1779		destroy_workqueue(glock_workqueue);
1780		rhashtable_destroy(&gl_hash_table);
1781		return -ENOMEM;
1782	}
1783
1784	register_shrinker(&glock_shrinker);
 
 
 
 
 
 
1785
1786	return 0;
1787}
1788
1789void gfs2_glock_exit(void)
1790{
1791	unregister_shrinker(&glock_shrinker);
1792	rhashtable_destroy(&gl_hash_table);
1793	destroy_workqueue(glock_workqueue);
1794	destroy_workqueue(gfs2_delete_workqueue);
1795}
1796
1797static void gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1798{
1799	do {
1800		gi->gl = rhashtable_walk_next(&gi->hti);
1801		if (IS_ERR(gi->gl)) {
1802			if (PTR_ERR(gi->gl) == -EAGAIN)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1803				continue;
1804			gi->gl = NULL;
1805		}
1806	/* Skip entries for other sb and dead entries */
1807	} while ((gi->gl) && ((gi->sdp != gi->gl->gl_name.ln_sbd) ||
1808			      __lockref_is_dead(&gi->gl->gl_lockref)));
1809}
1810
1811static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
 
1812{
1813	struct gfs2_glock_iter *gi = seq->private;
1814	loff_t n = *pos;
1815	int ret;
1816
1817	if (gi->last_pos <= *pos)
1818		n = (*pos - gi->last_pos);
1819
1820	ret = rhashtable_walk_start(&gi->hti);
1821	if (ret)
1822		return NULL;
 
 
 
 
 
1823
1824	do {
1825		gfs2_glock_iter_next(gi);
1826	} while (gi->gl && n--);
1827
 
1828	gi->last_pos = *pos;
1829	return gi->gl;
1830}
1831
1832static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1833				 loff_t *pos)
1834{
1835	struct gfs2_glock_iter *gi = seq->private;
1836
1837	(*pos)++;
1838	gi->last_pos = *pos;
1839	gfs2_glock_iter_next(gi);
1840	return gi->gl;
1841}
1842
1843static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
 
1844{
1845	struct gfs2_glock_iter *gi = seq->private;
1846
1847	gi->gl = NULL;
1848	rhashtable_walk_stop(&gi->hti);
1849}
1850
1851static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1852{
1853	dump_glock(seq, iter_ptr);
1854	return 0;
1855}
1856
1857static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
1858{
1859	preempt_disable();
1860	if (*pos >= GFS2_NR_SBSTATS)
1861		return NULL;
1862	return pos;
1863}
1864
1865static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
1866				   loff_t *pos)
1867{
1868	(*pos)++;
1869	if (*pos >= GFS2_NR_SBSTATS)
1870		return NULL;
1871	return pos;
1872}
1873
1874static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
1875{
1876	preempt_enable();
1877}
1878
1879static const struct seq_operations gfs2_glock_seq_ops = {
1880	.start = gfs2_glock_seq_start,
1881	.next  = gfs2_glock_seq_next,
1882	.stop  = gfs2_glock_seq_stop,
1883	.show  = gfs2_glock_seq_show,
1884};
1885
1886static const struct seq_operations gfs2_glstats_seq_ops = {
1887	.start = gfs2_glock_seq_start,
1888	.next  = gfs2_glock_seq_next,
1889	.stop  = gfs2_glock_seq_stop,
1890	.show  = gfs2_glstats_seq_show,
1891};
1892
1893static const struct seq_operations gfs2_sbstats_seq_ops = {
1894	.start = gfs2_sbstats_seq_start,
1895	.next  = gfs2_sbstats_seq_next,
1896	.stop  = gfs2_sbstats_seq_stop,
1897	.show  = gfs2_sbstats_seq_show,
1898};
1899
1900#define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)
1901
1902static int gfs2_glocks_open(struct inode *inode, struct file *file)
 
1903{
1904	int ret = seq_open_private(file, &gfs2_glock_seq_ops,
1905				   sizeof(struct gfs2_glock_iter));
1906	if (ret == 0) {
1907		struct seq_file *seq = file->private_data;
1908		struct gfs2_glock_iter *gi = seq->private;
1909
1910		gi->sdp = inode->i_private;
1911		gi->last_pos = 0;
1912		seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
1913		if (seq->buf)
1914			seq->size = GFS2_SEQ_GOODSIZE;
 
 
 
 
 
1915		gi->gl = NULL;
1916		ret = rhashtable_walk_init(&gl_hash_table, &gi->hti);
1917	}
1918	return ret;
1919}
1920
 
 
 
 
 
1921static int gfs2_glocks_release(struct inode *inode, struct file *file)
1922{
1923	struct seq_file *seq = file->private_data;
1924	struct gfs2_glock_iter *gi = seq->private;
1925
1926	gi->gl = NULL;
 
1927	rhashtable_walk_exit(&gi->hti);
1928	return seq_release_private(inode, file);
1929}
1930
1931static int gfs2_glstats_open(struct inode *inode, struct file *file)
1932{
1933	int ret = seq_open_private(file, &gfs2_glstats_seq_ops,
1934				   sizeof(struct gfs2_glock_iter));
1935	if (ret == 0) {
1936		struct seq_file *seq = file->private_data;
1937		struct gfs2_glock_iter *gi = seq->private;
1938		gi->sdp = inode->i_private;
1939		gi->last_pos = 0;
1940		seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
1941		if (seq->buf)
1942			seq->size = GFS2_SEQ_GOODSIZE;
1943		gi->gl = NULL;
1944		ret = rhashtable_walk_init(&gl_hash_table, &gi->hti);
1945	}
1946	return ret;
1947}
1948
1949static int gfs2_sbstats_open(struct inode *inode, struct file *file)
1950{
1951	int ret = seq_open(file, &gfs2_sbstats_seq_ops);
1952	if (ret == 0) {
1953		struct seq_file *seq = file->private_data;
1954		seq->private = inode->i_private;  /* sdp */
1955	}
1956	return ret;
1957}
1958
1959static const struct file_operations gfs2_glocks_fops = {
1960	.owner   = THIS_MODULE,
1961	.open    = gfs2_glocks_open,
1962	.read    = seq_read,
1963	.llseek  = seq_lseek,
1964	.release = gfs2_glocks_release,
1965};
1966
1967static const struct file_operations gfs2_glstats_fops = {
1968	.owner   = THIS_MODULE,
1969	.open    = gfs2_glstats_open,
1970	.read    = seq_read,
1971	.llseek  = seq_lseek,
1972	.release = gfs2_glocks_release,
1973};
1974
1975static const struct file_operations gfs2_sbstats_fops = {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1976	.owner   = THIS_MODULE,
1977	.open	 = gfs2_sbstats_open,
1978	.read    = seq_read,
1979	.llseek  = seq_lseek,
1980	.release = seq_release,
1981};
1982
1983int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
 
 
1984{
1985	struct dentry *dent;
1986
1987	dent = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
1988	if (IS_ERR_OR_NULL(dent))
1989		goto fail;
1990	sdp->debugfs_dir = dent;
1991
1992	dent = debugfs_create_file("glocks",
1993				   S_IFREG | S_IRUGO,
1994				   sdp->debugfs_dir, sdp,
1995				   &gfs2_glocks_fops);
1996	if (IS_ERR_OR_NULL(dent))
1997		goto fail;
1998	sdp->debugfs_dentry_glocks = dent;
1999
2000	dent = debugfs_create_file("glstats",
2001				   S_IFREG | S_IRUGO,
2002				   sdp->debugfs_dir, sdp,
2003				   &gfs2_glstats_fops);
2004	if (IS_ERR_OR_NULL(dent))
2005		goto fail;
2006	sdp->debugfs_dentry_glstats = dent;
2007
2008	dent = debugfs_create_file("sbstats",
2009				   S_IFREG | S_IRUGO,
2010				   sdp->debugfs_dir, sdp,
2011				   &gfs2_sbstats_fops);
2012	if (IS_ERR_OR_NULL(dent))
2013		goto fail;
2014	sdp->debugfs_dentry_sbstats = dent;
2015
2016	return 0;
2017fail:
2018	gfs2_delete_debugfs_file(sdp);
2019	return dent ? PTR_ERR(dent) : -ENOMEM;
 
 
 
 
2020}
2021
2022void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
2023{
2024	if (sdp->debugfs_dir) {
2025		if (sdp->debugfs_dentry_glocks) {
2026			debugfs_remove(sdp->debugfs_dentry_glocks);
2027			sdp->debugfs_dentry_glocks = NULL;
2028		}
2029		if (sdp->debugfs_dentry_glstats) {
2030			debugfs_remove(sdp->debugfs_dentry_glstats);
2031			sdp->debugfs_dentry_glstats = NULL;
2032		}
2033		if (sdp->debugfs_dentry_sbstats) {
2034			debugfs_remove(sdp->debugfs_dentry_sbstats);
2035			sdp->debugfs_dentry_sbstats = NULL;
2036		}
2037		debugfs_remove(sdp->debugfs_dir);
2038		sdp->debugfs_dir = NULL;
2039	}
2040}
2041
2042int gfs2_register_debugfs(void)
2043{
2044	gfs2_root = debugfs_create_dir("gfs2", NULL);
2045	if (IS_ERR(gfs2_root))
2046		return PTR_ERR(gfs2_root);
2047	return gfs2_root ? 0 : -ENOMEM;
2048}
2049
2050void gfs2_unregister_debugfs(void)
2051{
2052	debugfs_remove(gfs2_root);
2053	gfs2_root = NULL;
2054}