glock.c 52.2 KB
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/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
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 * Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
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 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
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 * of the GNU General Public License version 2.
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 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/buffer_head.h>
#include <linux/delay.h>
#include <linux/sort.h>
#include <linux/jhash.h>
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#include <linux/kallsyms.h>
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#include <linux/gfs2_ondisk.h>
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#include <linux/list.h>
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#include <linux/wait.h>
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#include <linux/module.h>
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#include <asm/uaccess.h>
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#include <linux/seq_file.h>
#include <linux/debugfs.h>
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#include <linux/kthread.h>
#include <linux/freezer.h>
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#include <linux/workqueue.h>
#include <linux/jiffies.h>
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#include <linux/rcupdate.h>
#include <linux/rculist_bl.h>
#include <linux/bit_spinlock.h>
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#include <linux/percpu.h>
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#include <linux/list_sort.h>
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#include <linux/lockref.h>
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#include "gfs2.h"
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#include "incore.h"
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#include "glock.h"
#include "glops.h"
#include "inode.h"
#include "lops.h"
#include "meta_io.h"
#include "quota.h"
#include "super.h"
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#include "util.h"
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#include "bmap.h"
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#define CREATE_TRACE_POINTS
#include "trace_gfs2.h"
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struct gfs2_glock_iter {
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	int hash;			/* hash bucket index           */
	unsigned nhash;			/* Index within current bucket */
	struct gfs2_sbd *sdp;		/* incore superblock           */
	struct gfs2_glock *gl;		/* current glock struct        */
	loff_t last_pos;		/* last position               */
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};

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typedef void (*glock_examiner) (struct gfs2_glock * gl);

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static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target);
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static struct dentry *gfs2_root;
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static struct workqueue_struct *glock_workqueue;
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struct workqueue_struct *gfs2_delete_workqueue;
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static LIST_HEAD(lru_list);
static atomic_t lru_count = ATOMIC_INIT(0);
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static DEFINE_SPINLOCK(lru_lock);
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#define GFS2_GL_HASH_SHIFT      15
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#define GFS2_GL_HASH_SIZE       (1 << GFS2_GL_HASH_SHIFT)
#define GFS2_GL_HASH_MASK       (GFS2_GL_HASH_SIZE - 1)

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static struct hlist_bl_head gl_hash_table[GFS2_GL_HASH_SIZE];
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static struct dentry *gfs2_root;
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/**
 * gl_hash() - Turn glock number into hash bucket number
 * @lock: The glock number
 *
 * Returns: The number of the corresponding hash bucket
 */

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static unsigned int gl_hash(const struct gfs2_sbd *sdp,
			    const struct lm_lockname *name)
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{
	unsigned int h;

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	h = jhash(&name->ln_number, sizeof(u64), 0);
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	h = jhash(&name->ln_type, sizeof(unsigned int), h);
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	h = jhash(&sdp, sizeof(struct gfs2_sbd *), h);
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	h &= GFS2_GL_HASH_MASK;

	return h;
}

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static inline void spin_lock_bucket(unsigned int hash)
{
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	hlist_bl_lock(&gl_hash_table[hash]);
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}
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static inline void spin_unlock_bucket(unsigned int hash)
{
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	hlist_bl_unlock(&gl_hash_table[hash]);
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}
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static void gfs2_glock_dealloc(struct rcu_head *rcu)
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{
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	struct gfs2_glock *gl = container_of(rcu, struct gfs2_glock, gl_rcu);
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	if (gl->gl_ops->go_flags & GLOF_ASPACE) {
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		kmem_cache_free(gfs2_glock_aspace_cachep, gl);
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	} else {
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		kfree(gl->gl_lksb.sb_lvbptr);
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		kmem_cache_free(gfs2_glock_cachep, gl);
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	}
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}

void gfs2_glock_free(struct gfs2_glock *gl)
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{
	struct gfs2_sbd *sdp = gl->gl_sbd;

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	call_rcu(&gl->gl_rcu, gfs2_glock_dealloc);
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	if (atomic_dec_and_test(&sdp->sd_glock_disposal))
		wake_up(&sdp->sd_glock_wait);
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}

/**
 * gfs2_glock_hold() - increment reference count on glock
 * @gl: The glock to hold
 *
 */

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static void gfs2_glock_hold(struct gfs2_glock *gl)
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{
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	GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
	lockref_get(&gl->gl_lockref);
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}

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/**
 * demote_ok - Check to see if it's ok to unlock a glock
 * @gl: the glock
 *
 * Returns: 1 if it's ok
 */

static int demote_ok(const struct gfs2_glock *gl)
{
	const struct gfs2_glock_operations *glops = gl->gl_ops;

	if (gl->gl_state == LM_ST_UNLOCKED)
		return 0;
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	if (!list_empty(&gl->gl_holders))
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		return 0;
	if (glops->go_demote_ok)
		return glops->go_demote_ok(gl);
	return 1;
}

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void gfs2_glock_add_to_lru(struct gfs2_glock *gl)
{
	spin_lock(&lru_lock);

	if (!list_empty(&gl->gl_lru))
		list_del_init(&gl->gl_lru);
	else
		atomic_inc(&lru_count);

	list_add_tail(&gl->gl_lru, &lru_list);
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	set_bit(GLF_LRU, &gl->gl_flags);
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	spin_unlock(&lru_lock);
}

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static void __gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
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{
	if (!list_empty(&gl->gl_lru)) {
		list_del_init(&gl->gl_lru);
		atomic_dec(&lru_count);
		clear_bit(GLF_LRU, &gl->gl_flags);
	}
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}

static void gfs2_glock_remove_from_lru(struct gfs2_glock *gl)
{
	spin_lock(&lru_lock);
	__gfs2_glock_remove_from_lru(gl);
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	spin_unlock(&lru_lock);
}

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/**
 * gfs2_glock_put() - Decrement reference count on glock
 * @gl: The glock to put
 *
 */

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void gfs2_glock_put(struct gfs2_glock *gl)
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{
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	struct gfs2_sbd *sdp = gl->gl_sbd;
	struct address_space *mapping = gfs2_glock2aspace(gl);
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	if (lockref_put_or_lock(&gl->gl_lockref))
		return;

	lockref_mark_dead(&gl->gl_lockref);

	spin_lock(&lru_lock);
	__gfs2_glock_remove_from_lru(gl);
	spin_unlock(&lru_lock);
	spin_unlock(&gl->gl_lockref.lock);
	spin_lock_bucket(gl->gl_hash);
	hlist_bl_del_rcu(&gl->gl_list);
	spin_unlock_bucket(gl->gl_hash);
	GLOCK_BUG_ON(gl, !list_empty(&gl->gl_holders));
	GLOCK_BUG_ON(gl, mapping && mapping->nrpages);
	trace_gfs2_glock_put(gl);
	sdp->sd_lockstruct.ls_ops->lm_put_lock(gl);
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}

/**
 * search_bucket() - Find struct gfs2_glock by lock number
 * @bucket: the bucket to search
 * @name: The lock name
 *
 * Returns: NULL, or the struct gfs2_glock with the requested number
 */

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static struct gfs2_glock *search_bucket(unsigned int hash,
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					const struct gfs2_sbd *sdp,
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					const struct lm_lockname *name)
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{
	struct gfs2_glock *gl;
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	struct hlist_bl_node *h;
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	hlist_bl_for_each_entry_rcu(gl, h, &gl_hash_table[hash], gl_list) {
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		if (!lm_name_equal(&gl->gl_name, name))
			continue;
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		if (gl->gl_sbd != sdp)
			continue;
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		if (lockref_get_not_dead(&gl->gl_lockref))
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			return gl;
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	}

	return NULL;
}

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/**
 * may_grant - check if its ok to grant a new lock
 * @gl: The glock
 * @gh: The lock request which we wish to grant
 *
 * Returns: true if its ok to grant the lock
 */

static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh)
{
	const struct gfs2_holder *gh_head = list_entry(gl->gl_holders.next, const struct gfs2_holder, gh_list);
	if ((gh->gh_state == LM_ST_EXCLUSIVE ||
	     gh_head->gh_state == LM_ST_EXCLUSIVE) && gh != gh_head)
		return 0;
	if (gl->gl_state == gh->gh_state)
		return 1;
	if (gh->gh_flags & GL_EXACT)
		return 0;
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	if (gl->gl_state == LM_ST_EXCLUSIVE) {
		if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED)
			return 1;
		if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED)
			return 1;
	}
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	if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY))
		return 1;
	return 0;
}

static void gfs2_holder_wake(struct gfs2_holder *gh)
{
	clear_bit(HIF_WAIT, &gh->gh_iflags);
	smp_mb__after_clear_bit();
	wake_up_bit(&gh->gh_iflags, HIF_WAIT);
}

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/**
 * do_error - Something unexpected has happened during a lock request
 *
 */

static inline void do_error(struct gfs2_glock *gl, const int ret)
{
	struct gfs2_holder *gh, *tmp;

	list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
			continue;
		if (ret & LM_OUT_ERROR)
			gh->gh_error = -EIO;
		else if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
			gh->gh_error = GLR_TRYFAILED;
		else
			continue;
		list_del_init(&gh->gh_list);
		trace_gfs2_glock_queue(gh, 0);
		gfs2_holder_wake(gh);
	}
}

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/**
 * do_promote - promote as many requests as possible on the current queue
 * @gl: The glock
 * 
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 * Returns: 1 if there is a blocked holder at the head of the list, or 2
 *          if a type specific operation is underway.
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 */

static int do_promote(struct gfs2_glock *gl)
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__releases(&gl->gl_spin)
__acquires(&gl->gl_spin)
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{
	const struct gfs2_glock_operations *glops = gl->gl_ops;
	struct gfs2_holder *gh, *tmp;
	int ret;

restart:
	list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) {
		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
			continue;
		if (may_grant(gl, gh)) {
			if (gh->gh_list.prev == &gl->gl_holders &&
			    glops->go_lock) {
				spin_unlock(&gl->gl_spin);
				/* FIXME: eliminate this eventually */
				ret = glops->go_lock(gh);
				spin_lock(&gl->gl_spin);
				if (ret) {
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					if (ret == 1)
						return 2;
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					gh->gh_error = ret;
					list_del_init(&gh->gh_list);
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					trace_gfs2_glock_queue(gh, 0);
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					gfs2_holder_wake(gh);
					goto restart;
				}
				set_bit(HIF_HOLDER, &gh->gh_iflags);
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				trace_gfs2_promote(gh, 1);
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				gfs2_holder_wake(gh);
				goto restart;
			}
			set_bit(HIF_HOLDER, &gh->gh_iflags);
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			trace_gfs2_promote(gh, 0);
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			gfs2_holder_wake(gh);
			continue;
		}
		if (gh->gh_list.prev == &gl->gl_holders)
			return 1;
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		do_error(gl, 0);
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		break;
	}
	return 0;
}

/**
 * find_first_waiter - find the first gh that's waiting for the glock
 * @gl: the glock
 */

static inline struct gfs2_holder *find_first_waiter(const struct gfs2_glock *gl)
{
	struct gfs2_holder *gh;

	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
		if (!test_bit(HIF_HOLDER, &gh->gh_iflags))
			return gh;
	}
	return NULL;
}

/**
 * state_change - record that the glock is now in a different state
 * @gl: the glock
 * @new_state the new state
 *
 */

static void state_change(struct gfs2_glock *gl, unsigned int new_state)
{
	int held1, held2;

	held1 = (gl->gl_state != LM_ST_UNLOCKED);
	held2 = (new_state != LM_ST_UNLOCKED);

	if (held1 != held2) {
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		GLOCK_BUG_ON(gl, __lockref_is_dead(&gl->gl_lockref));
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		if (held2)
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			gl->gl_lockref.count++;
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		else
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			gl->gl_lockref.count--;
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	}
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	if (held1 && held2 && list_empty(&gl->gl_holders))
		clear_bit(GLF_QUEUED, &gl->gl_flags);
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	if (new_state != gl->gl_target)
		/* shorten our minimum hold time */
		gl->gl_hold_time = max(gl->gl_hold_time - GL_GLOCK_HOLD_DECR,
				       GL_GLOCK_MIN_HOLD);
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	gl->gl_state = new_state;
	gl->gl_tchange = jiffies;
}

static void gfs2_demote_wake(struct gfs2_glock *gl)
{
	gl->gl_demote_state = LM_ST_EXCLUSIVE;
	clear_bit(GLF_DEMOTE, &gl->gl_flags);
	smp_mb__after_clear_bit();
	wake_up_bit(&gl->gl_flags, GLF_DEMOTE);
}

/**
 * finish_xmote - The DLM has replied to one of our lock requests
 * @gl: The glock
 * @ret: The status from the DLM
 *
 */

static void finish_xmote(struct gfs2_glock *gl, unsigned int ret)
{
	const struct gfs2_glock_operations *glops = gl->gl_ops;
	struct gfs2_holder *gh;
	unsigned state = ret & LM_OUT_ST_MASK;
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	int rv;
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	spin_lock(&gl->gl_spin);
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	trace_gfs2_glock_state_change(gl, state);
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	state_change(gl, state);
	gh = find_first_waiter(gl);

	/* Demote to UN request arrived during demote to SH or DF */
	if (test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags) &&
	    state != LM_ST_UNLOCKED && gl->gl_demote_state == LM_ST_UNLOCKED)
		gl->gl_target = LM_ST_UNLOCKED;

	/* Check for state != intended state */
	if (unlikely(state != gl->gl_target)) {
		if (gh && !test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags)) {
			/* move to back of queue and try next entry */
			if (ret & LM_OUT_CANCELED) {
				if ((gh->gh_flags & LM_FLAG_PRIORITY) == 0)
					list_move_tail(&gh->gh_list, &gl->gl_holders);
				gh = find_first_waiter(gl);
				gl->gl_target = gh->gh_state;
				goto retry;
			}
			/* Some error or failed "try lock" - report it */
			if ((ret & LM_OUT_ERROR) ||
			    (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
				gl->gl_target = gl->gl_state;
				do_error(gl, ret);
				goto out;
			}
		}
		switch(state) {
		/* Unlocked due to conversion deadlock, try again */
		case LM_ST_UNLOCKED:
retry:
			do_xmote(gl, gh, gl->gl_target);
			break;
		/* Conversion fails, unlock and try again */
		case LM_ST_SHARED:
		case LM_ST_DEFERRED:
			do_xmote(gl, gh, LM_ST_UNLOCKED);
			break;
		default: /* Everything else */
			printk(KERN_ERR "GFS2: wanted %u got %u\n", gl->gl_target, state);
			GLOCK_BUG_ON(gl, 1);
		}
		spin_unlock(&gl->gl_spin);
		return;
	}

	/* Fast path - we got what we asked for */
	if (test_and_clear_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags))
		gfs2_demote_wake(gl);
	if (state != LM_ST_UNLOCKED) {
		if (glops->go_xmote_bh) {
			spin_unlock(&gl->gl_spin);
			rv = glops->go_xmote_bh(gl, gh);
			spin_lock(&gl->gl_spin);
			if (rv) {
				do_error(gl, rv);
				goto out;
			}
		}
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		rv = do_promote(gl);
		if (rv == 2)
			goto out_locked;
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	}
out:
	clear_bit(GLF_LOCK, &gl->gl_flags);
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out_locked:
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	spin_unlock(&gl->gl_spin);
}

/**
 * do_xmote - Calls the DLM to change the state of a lock
 * @gl: The lock state
 * @gh: The holder (only for promotes)
 * @target: The target lock state
 *
 */

static void do_xmote(struct gfs2_glock *gl, struct gfs2_holder *gh, unsigned int target)
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__releases(&gl->gl_spin)
__acquires(&gl->gl_spin)
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{
	const struct gfs2_glock_operations *glops = gl->gl_ops;
	struct gfs2_sbd *sdp = gl->gl_sbd;
	unsigned int lck_flags = gh ? gh->gh_flags : 0;
	int ret;

	lck_flags &= (LM_FLAG_TRY | LM_FLAG_TRY_1CB | LM_FLAG_NOEXP |
		      LM_FLAG_PRIORITY);
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	GLOCK_BUG_ON(gl, gl->gl_state == target);
	GLOCK_BUG_ON(gl, gl->gl_state == gl->gl_target);
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	if ((target == LM_ST_UNLOCKED || target == LM_ST_DEFERRED) &&
	    glops->go_inval) {
		set_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);
		do_error(gl, 0); /* Fail queued try locks */
	}
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	gl->gl_req = target;
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	set_bit(GLF_BLOCKING, &gl->gl_flags);
	if ((gl->gl_req == LM_ST_UNLOCKED) ||
	    (gl->gl_state == LM_ST_EXCLUSIVE) ||
	    (lck_flags & (LM_FLAG_TRY|LM_FLAG_TRY_1CB)))
		clear_bit(GLF_BLOCKING, &gl->gl_flags);
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	spin_unlock(&gl->gl_spin);
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	if (glops->go_sync)
		glops->go_sync(gl);
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	if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
		glops->go_inval(gl, target == LM_ST_DEFERRED ? 0 : DIO_METADATA);
	clear_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags);

	gfs2_glock_hold(gl);
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	if (sdp->sd_lockstruct.ls_ops->lm_lock)	{
		/* lock_dlm */
		ret = sdp->sd_lockstruct.ls_ops->lm_lock(gl, target, lck_flags);
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		if (ret) {
			printk(KERN_ERR "GFS2: lm_lock ret %d\n", ret);
			GLOCK_BUG_ON(gl, 1);
		}
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	} else { /* lock_nolock */
		finish_xmote(gl, target);
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		if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
			gfs2_glock_put(gl);
	}
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	spin_lock(&gl->gl_spin);
}

/**
 * find_first_holder - find the first "holder" gh
 * @gl: the glock
 */

static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl)
{
	struct gfs2_holder *gh;

	if (!list_empty(&gl->gl_holders)) {
		gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
			return gh;
	}
	return NULL;
}

/**
 * run_queue - do all outstanding tasks related to a glock
 * @gl: The glock in question
 * @nonblock: True if we must not block in run_queue
 *
 */

static void run_queue(struct gfs2_glock *gl, const int nonblock)
582 583
__releases(&gl->gl_spin)
__acquires(&gl->gl_spin)
584 585
{
	struct gfs2_holder *gh = NULL;
586
	int ret;
587 588 589 590 591 592 593 594 595

	if (test_and_set_bit(GLF_LOCK, &gl->gl_flags))
		return;

	GLOCK_BUG_ON(gl, test_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags));

	if (test_bit(GLF_DEMOTE, &gl->gl_flags) &&
	    gl->gl_demote_state != gl->gl_state) {
		if (find_first_holder(gl))
596
			goto out_unlock;
597 598 599
		if (nonblock)
			goto out_sched;
		set_bit(GLF_DEMOTE_IN_PROGRESS, &gl->gl_flags);
600
		GLOCK_BUG_ON(gl, gl->gl_demote_state == LM_ST_EXCLUSIVE);
601 602 603 604
		gl->gl_target = gl->gl_demote_state;
	} else {
		if (test_bit(GLF_DEMOTE, &gl->gl_flags))
			gfs2_demote_wake(gl);
605 606
		ret = do_promote(gl);
		if (ret == 0)
607
			goto out_unlock;
608
		if (ret == 2)
609
			goto out;
610 611 612 613 614 615
		gh = find_first_waiter(gl);
		gl->gl_target = gh->gh_state;
		if (!(gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)))
			do_error(gl, 0); /* Fail queued try locks */
	}
	do_xmote(gl, gh, gl->gl_target);
616
out:
617 618 619
	return;

out_sched:
620 621
	clear_bit(GLF_LOCK, &gl->gl_flags);
	smp_mb__after_clear_bit();
S
Steven Whitehouse 已提交
622
	gl->gl_lockref.count++;
623
	if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
S
Steven Whitehouse 已提交
624
		gl->gl_lockref.count--;
625 626
	return;

627
out_unlock:
628
	clear_bit(GLF_LOCK, &gl->gl_flags);
629 630
	smp_mb__after_clear_bit();
	return;
631 632
}

633 634 635 636
static void delete_work_func(struct work_struct *work)
{
	struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_delete);
	struct gfs2_sbd *sdp = gl->gl_sbd;
637
	struct gfs2_inode *ip;
638
	struct inode *inode;
639 640 641 642
	u64 no_addr = gl->gl_name.ln_number;

	ip = gl->gl_object;
	/* Note: Unsafe to dereference ip as we don't hold right refs/locks */
643 644

	if (ip)
645
		inode = gfs2_ilookup(sdp->sd_vfs, no_addr, 1);
646 647 648 649 650
	else
		inode = gfs2_lookup_by_inum(sdp, no_addr, NULL, GFS2_BLKST_UNLINKED);
	if (inode && !IS_ERR(inode)) {
		d_prune_aliases(inode);
		iput(inode);
651 652 653 654
	}
	gfs2_glock_put(gl);
}

655 656
static void glock_work_func(struct work_struct *work)
{
657
	unsigned long delay = 0;
658
	struct gfs2_glock *gl = container_of(work, struct gfs2_glock, gl_work.work);
659
	int drop_ref = 0;
660

661
	if (test_and_clear_bit(GLF_REPLY_PENDING, &gl->gl_flags)) {
662
		finish_xmote(gl, gl->gl_reply);
663 664
		drop_ref = 1;
	}
665
	spin_lock(&gl->gl_spin);
666
	if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
667 668
	    gl->gl_state != LM_ST_UNLOCKED &&
	    gl->gl_demote_state != LM_ST_EXCLUSIVE) {
669
		unsigned long holdtime, now = jiffies;
670

671
		holdtime = gl->gl_tchange + gl->gl_hold_time;
672 673
		if (time_before(now, holdtime))
			delay = holdtime - now;
674 675 676 677 678

		if (!delay) {
			clear_bit(GLF_PENDING_DEMOTE, &gl->gl_flags);
			set_bit(GLF_DEMOTE, &gl->gl_flags);
		}
679 680
	}
	run_queue(gl, 0);
681
	spin_unlock(&gl->gl_spin);
682
	if (!delay)
683
		gfs2_glock_put(gl);
684 685 686 687 688 689
	else {
		if (gl->gl_name.ln_type != LM_TYPE_INODE)
			delay = 0;
		if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
			gfs2_glock_put(gl);
	}
690 691
	if (drop_ref)
		gfs2_glock_put(gl);
692 693
}

D
David Teigland 已提交
694 695 696 697 698 699 700 701 702 703 704 705 706
/**
 * gfs2_glock_get() - Get a glock, or create one if one doesn't exist
 * @sdp: The GFS2 superblock
 * @number: the lock number
 * @glops: The glock_operations to use
 * @create: If 0, don't create the glock if it doesn't exist
 * @glp: the glock is returned here
 *
 * This does not lock a glock, just finds/creates structures for one.
 *
 * Returns: errno
 */

707
int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
708
		   const struct gfs2_glock_operations *glops, int create,
D
David Teigland 已提交
709 710
		   struct gfs2_glock **glp)
{
711
	struct super_block *s = sdp->sd_vfs;
712
	struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
D
David Teigland 已提交
713
	struct gfs2_glock *gl, *tmp;
714
	unsigned int hash = gl_hash(sdp, &name);
715
	struct address_space *mapping;
716
	struct kmem_cache *cachep;
D
David Teigland 已提交
717

718
	rcu_read_lock();
719
	gl = search_bucket(hash, sdp, &name);
720
	rcu_read_unlock();
D
David Teigland 已提交
721

722 723
	*glp = gl;
	if (gl)
D
David Teigland 已提交
724
		return 0;
725 726
	if (!create)
		return -ENOENT;
D
David Teigland 已提交
727

728
	if (glops->go_flags & GLOF_ASPACE)
729
		cachep = gfs2_glock_aspace_cachep;
730
	else
731 732
		cachep = gfs2_glock_cachep;
	gl = kmem_cache_alloc(cachep, GFP_KERNEL);
D
David Teigland 已提交
733 734 735
	if (!gl)
		return -ENOMEM;

736 737 738
	memset(&gl->gl_lksb, 0, sizeof(struct dlm_lksb));

	if (glops->go_flags & GLOF_LVB) {
739 740
		gl->gl_lksb.sb_lvbptr = kzalloc(GFS2_MIN_LVB_SIZE, GFP_KERNEL);
		if (!gl->gl_lksb.sb_lvbptr) {
741 742 743 744 745
			kmem_cache_free(cachep, gl);
			return -ENOMEM;
		}
	}

746
	atomic_inc(&sdp->sd_glock_disposal);
747
	gl->gl_sbd = sdp;
748
	gl->gl_flags = 0;
D
David Teigland 已提交
749
	gl->gl_name = name;
S
Steven Whitehouse 已提交
750
	gl->gl_lockref.count = 1;
D
David Teigland 已提交
751
	gl->gl_state = LM_ST_UNLOCKED;
752
	gl->gl_target = LM_ST_UNLOCKED;
753
	gl->gl_demote_state = LM_ST_EXCLUSIVE;
754
	gl->gl_hash = hash;
D
David Teigland 已提交
755
	gl->gl_ops = glops;
756 757 758 759 760 761 762
	gl->gl_dstamp = ktime_set(0, 0);
	preempt_disable();
	/* We use the global stats to estimate the initial per-glock stats */
	gl->gl_stats = this_cpu_ptr(sdp->sd_lkstats)->lkstats[glops->go_type];
	preempt_enable();
	gl->gl_stats.stats[GFS2_LKS_DCOUNT] = 0;
	gl->gl_stats.stats[GFS2_LKS_QCOUNT] = 0;
763
	gl->gl_tchange = jiffies;
764
	gl->gl_object = NULL;
765
	gl->gl_hold_time = GL_GLOCK_DFT_HOLD;
766
	INIT_DELAYED_WORK(&gl->gl_work, glock_work_func);
767
	INIT_WORK(&gl->gl_delete, delete_work_func);
D
David Teigland 已提交
768

769 770 771 772 773 774
	mapping = gfs2_glock2aspace(gl);
	if (mapping) {
                mapping->a_ops = &gfs2_meta_aops;
		mapping->host = s->s_bdev->bd_inode;
		mapping->flags = 0;
		mapping_set_gfp_mask(mapping, GFP_NOFS);
775
		mapping->private_data = NULL;
776 777
		mapping->backing_dev_info = s->s_bdi;
		mapping->writeback_index = 0;
D
David Teigland 已提交
778 779
	}

780
	spin_lock_bucket(hash);
781
	tmp = search_bucket(hash, sdp, &name);
D
David Teigland 已提交
782
	if (tmp) {
783
		spin_unlock_bucket(hash);
784
		kfree(gl->gl_lksb.sb_lvbptr);
785
		kmem_cache_free(cachep, gl);
786
		atomic_dec(&sdp->sd_glock_disposal);
D
David Teigland 已提交
787 788
		gl = tmp;
	} else {
789 790
		hlist_bl_add_head_rcu(&gl->gl_list, &gl_hash_table[hash]);
		spin_unlock_bucket(hash);
D
David Teigland 已提交
791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806
	}

	*glp = gl;

	return 0;
}

/**
 * gfs2_holder_init - initialize a struct gfs2_holder in the default way
 * @gl: the glock
 * @state: the state we're requesting
 * @flags: the modifier flags
 * @gh: the holder structure
 *
 */

807
void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
D
David Teigland 已提交
808 809 810 811
		      struct gfs2_holder *gh)
{
	INIT_LIST_HEAD(&gh->gh_list);
	gh->gh_gl = gl;
S
Steven Whitehouse 已提交
812
	gh->gh_ip = (unsigned long)__builtin_return_address(0);
813
	gh->gh_owner_pid = get_pid(task_pid(current));
D
David Teigland 已提交
814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830
	gh->gh_state = state;
	gh->gh_flags = flags;
	gh->gh_error = 0;
	gh->gh_iflags = 0;
	gfs2_glock_hold(gl);
}

/**
 * gfs2_holder_reinit - reinitialize a struct gfs2_holder so we can requeue it
 * @state: the state we're requesting
 * @flags: the modifier flags
 * @gh: the holder structure
 *
 * Don't mess with the glock.
 *
 */

831
void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
D
David Teigland 已提交
832 833
{
	gh->gh_state = state;
834
	gh->gh_flags = flags;
835
	gh->gh_iflags = 0;
S
Steven Whitehouse 已提交
836
	gh->gh_ip = (unsigned long)__builtin_return_address(0);
B
Bob Peterson 已提交
837 838 839
	if (gh->gh_owner_pid)
		put_pid(gh->gh_owner_pid);
	gh->gh_owner_pid = get_pid(task_pid(current));
D
David Teigland 已提交
840 841 842 843 844 845 846 847 848 849
}

/**
 * gfs2_holder_uninit - uninitialize a holder structure (drop glock reference)
 * @gh: the holder structure
 *
 */

void gfs2_holder_uninit(struct gfs2_holder *gh)
{
850
	put_pid(gh->gh_owner_pid);
D
David Teigland 已提交
851 852
	gfs2_glock_put(gh->gh_gl);
	gh->gh_gl = NULL;
S
Steven Whitehouse 已提交
853
	gh->gh_ip = 0;
D
David Teigland 已提交
854 855
}

856 857 858 859 860 861 862 863 864 865
/**
 * gfs2_glock_holder_wait
 * @word: unused
 *
 * This function and gfs2_glock_demote_wait both show up in the WCHAN
 * field. Thus I've separated these otherwise identical functions in
 * order to be more informative to the user.
 */

static int gfs2_glock_holder_wait(void *word)
866 867 868 869 870
{
        schedule();
        return 0;
}

871 872 873 874 875 876
static int gfs2_glock_demote_wait(void *word)
{
	schedule();
	return 0;
}

877 878 879 880 881 882 883 884
/**
 * gfs2_glock_wait - wait on a glock acquisition
 * @gh: the glock holder
 *
 * Returns: 0 on success
 */

int gfs2_glock_wait(struct gfs2_holder *gh)
885
{
886 887
	unsigned long time1 = jiffies;

888
	might_sleep();
889
	wait_on_bit(&gh->gh_iflags, HIF_WAIT, gfs2_glock_holder_wait, TASK_UNINTERRUPTIBLE);
890 891 892 893 894
	if (time_after(jiffies, time1 + HZ)) /* have we waited > a second? */
		/* Lengthen the minimum hold time. */
		gh->gh_gl->gl_hold_time = min(gh->gh_gl->gl_hold_time +
					      GL_GLOCK_HOLD_INCR,
					      GL_GLOCK_MAX_HOLD);
895
	return gh->gh_error;
896 897
}

D
David Teigland 已提交
898
/**
899 900 901
 * handle_callback - process a demote request
 * @gl: the glock
 * @state: the state the caller wants us to change to
D
David Teigland 已提交
902
 *
903 904
 * There are only two requests that we are going to see in actual
 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
D
David Teigland 已提交
905 906
 */

907
static void handle_callback(struct gfs2_glock *gl, unsigned int state,
908
			    unsigned long delay, bool remote)
D
David Teigland 已提交
909
{
910
	int bit = delay ? GLF_PENDING_DEMOTE : GLF_DEMOTE;
D
David Teigland 已提交
911

912 913 914 915 916 917 918
	set_bit(bit, &gl->gl_flags);
	if (gl->gl_demote_state == LM_ST_EXCLUSIVE) {
		gl->gl_demote_state = state;
		gl->gl_demote_time = jiffies;
	} else if (gl->gl_demote_state != LM_ST_UNLOCKED &&
			gl->gl_demote_state != state) {
		gl->gl_demote_state = LM_ST_UNLOCKED;
D
David Teigland 已提交
919
	}
920
	if (gl->gl_ops->go_callback)
921
		gl->gl_ops->go_callback(gl, remote);
922
	trace_gfs2_demote_rq(gl, remote);
D
David Teigland 已提交
923 924
}

925
void gfs2_print_dbg(struct seq_file *seq, const char *fmt, ...)
926
{
927
	struct va_format vaf;
928 929 930
	va_list args;

	va_start(args, fmt);
931

932
	if (seq) {
933
		seq_vprintf(seq, fmt, args);
934
	} else {
935 936 937 938
		vaf.fmt = fmt;
		vaf.va = &args;

		printk(KERN_ERR " %pV", &vaf);
939
	}
940

941 942 943
	va_end(args);
}

D
David Teigland 已提交
944 945 946 947
/**
 * add_to_queue - Add a holder to the wait queue (but look for recursion)
 * @gh: the holder structure to add
 *
948 949 950 951
 * Eventually we should move the recursive locking trap to a
 * debugging option or something like that. This is the fast
 * path and needs to have the minimum number of distractions.
 * 
D
David Teigland 已提交
952 953
 */

954
static inline void add_to_queue(struct gfs2_holder *gh)
955 956
__releases(&gl->gl_spin)
__acquires(&gl->gl_spin)
D
David Teigland 已提交
957 958
{
	struct gfs2_glock *gl = gh->gh_gl;
959 960 961
	struct gfs2_sbd *sdp = gl->gl_sbd;
	struct list_head *insert_pt = NULL;
	struct gfs2_holder *gh2;
962
	int try_futile = 0;
D
David Teigland 已提交
963

964
	BUG_ON(gh->gh_owner_pid == NULL);
965 966
	if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
		BUG();
967

968 969
	if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
		if (test_bit(GLF_LOCK, &gl->gl_flags))
970
			try_futile = !may_grant(gl, gh);
971 972 973 974 975 976 977 978
		if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags))
			goto fail;
	}

	list_for_each_entry(gh2, &gl->gl_holders, gh_list) {
		if (unlikely(gh2->gh_owner_pid == gh->gh_owner_pid &&
		    (gh->gh_gl->gl_ops->go_type != LM_TYPE_FLOCK)))
			goto trap_recursive;
979 980
		if (try_futile &&
		    !(gh2->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))) {
981 982 983 984
fail:
			gh->gh_error = GLR_TRYFAILED;
			gfs2_holder_wake(gh);
			return;
985
		}
986 987 988 989 990
		if (test_bit(HIF_HOLDER, &gh2->gh_iflags))
			continue;
		if (unlikely((gh->gh_flags & LM_FLAG_PRIORITY) && !insert_pt))
			insert_pt = &gh2->gh_list;
	}
991
	set_bit(GLF_QUEUED, &gl->gl_flags);
992
	trace_gfs2_glock_queue(gh, 1);
993 994
	gfs2_glstats_inc(gl, GFS2_LKS_QCOUNT);
	gfs2_sbstats_inc(gl, GFS2_LKS_QCOUNT);
995 996 997 998 999 1000 1001 1002 1003 1004 1005
	if (likely(insert_pt == NULL)) {
		list_add_tail(&gh->gh_list, &gl->gl_holders);
		if (unlikely(gh->gh_flags & LM_FLAG_PRIORITY))
			goto do_cancel;
		return;
	}
	list_add_tail(&gh->gh_list, insert_pt);
do_cancel:
	gh = list_entry(gl->gl_holders.next, struct gfs2_holder, gh_list);
	if (!(gh->gh_flags & LM_FLAG_PRIORITY)) {
		spin_unlock(&gl->gl_spin);
S
Steven Whitehouse 已提交
1006
		if (sdp->sd_lockstruct.ls_ops->lm_cancel)
1007
			sdp->sd_lockstruct.ls_ops->lm_cancel(gl);
1008
		spin_lock(&gl->gl_spin);
D
David Teigland 已提交
1009
	}
1010
	return;
D
David Teigland 已提交
1011

1012
trap_recursive:
J
Joe Perches 已提交
1013
	printk(KERN_ERR "original: %pSR\n", (void *)gh2->gh_ip);
1014 1015 1016
	printk(KERN_ERR "pid: %d\n", pid_nr(gh2->gh_owner_pid));
	printk(KERN_ERR "lock type: %d req lock state : %d\n",
	       gh2->gh_gl->gl_name.ln_type, gh2->gh_state);
J
Joe Perches 已提交
1017
	printk(KERN_ERR "new: %pSR\n", (void *)gh->gh_ip);
1018 1019 1020
	printk(KERN_ERR "pid: %d\n", pid_nr(gh->gh_owner_pid));
	printk(KERN_ERR "lock type: %d req lock state : %d\n",
	       gh->gh_gl->gl_name.ln_type, gh->gh_state);
1021
	gfs2_dump_glock(NULL, gl);
1022
	BUG();
D
David Teigland 已提交
1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039
}

/**
 * gfs2_glock_nq - enqueue a struct gfs2_holder onto a glock (acquire a glock)
 * @gh: the holder structure
 *
 * if (gh->gh_flags & GL_ASYNC), this never returns an error
 *
 * Returns: 0, GLR_TRYFAILED, or errno on failure
 */

int gfs2_glock_nq(struct gfs2_holder *gh)
{
	struct gfs2_glock *gl = gh->gh_gl;
	struct gfs2_sbd *sdp = gl->gl_sbd;
	int error = 0;

1040
	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags)))
D
David Teigland 已提交
1041 1042
		return -EIO;

1043 1044 1045
	if (test_bit(GLF_LRU, &gl->gl_flags))
		gfs2_glock_remove_from_lru(gl);

D
David Teigland 已提交
1046 1047
	spin_lock(&gl->gl_spin);
	add_to_queue(gh);
1048 1049 1050
	if ((LM_FLAG_NOEXP & gh->gh_flags) &&
	    test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
		set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1051
	run_queue(gl, 1);
D
David Teigland 已提交
1052 1053
	spin_unlock(&gl->gl_spin);

1054 1055
	if (!(gh->gh_flags & GL_ASYNC))
		error = gfs2_glock_wait(gh);
D
David Teigland 已提交
1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068

	return error;
}

/**
 * gfs2_glock_poll - poll to see if an async request has been completed
 * @gh: the holder
 *
 * Returns: 1 if the request is ready to be gfs2_glock_wait()ed on
 */

int gfs2_glock_poll(struct gfs2_holder *gh)
{
1069
	return test_bit(HIF_WAIT, &gh->gh_iflags) ? 0 : 1;
D
David Teigland 已提交
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080
}

/**
 * gfs2_glock_dq - dequeue a struct gfs2_holder from a glock (release a glock)
 * @gh: the glock holder
 *
 */

void gfs2_glock_dq(struct gfs2_holder *gh)
{
	struct gfs2_glock *gl = gh->gh_gl;
1081
	const struct gfs2_glock_operations *glops = gl->gl_ops;
1082
	unsigned delay = 0;
1083
	int fast_path = 0;
D
David Teigland 已提交
1084

1085
	spin_lock(&gl->gl_spin);
D
David Teigland 已提交
1086
	if (gh->gh_flags & GL_NOCACHE)
1087
		handle_callback(gl, LM_ST_UNLOCKED, 0, false);
D
David Teigland 已提交
1088 1089

	list_del_init(&gh->gh_list);
1090
	if (find_first_holder(gl) == NULL) {
1091
		if (glops->go_unlock) {
1092
			GLOCK_BUG_ON(gl, test_and_set_bit(GLF_LOCK, &gl->gl_flags));
1093
			spin_unlock(&gl->gl_spin);
D
David Teigland 已提交
1094
			glops->go_unlock(gh);
1095
			spin_lock(&gl->gl_spin);
1096
			clear_bit(GLF_LOCK, &gl->gl_flags);
1097
		}
1098 1099 1100 1101
		if (list_empty(&gl->gl_holders) &&
		    !test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
		    !test_bit(GLF_DEMOTE, &gl->gl_flags))
			fast_path = 1;
D
David Teigland 已提交
1102
	}
1103 1104 1105
	if (!test_bit(GLF_LFLUSH, &gl->gl_flags) && demote_ok(gl))
		gfs2_glock_add_to_lru(gl);

S
Steven Whitehouse 已提交
1106
	trace_gfs2_glock_queue(gh, 0);
D
David Teigland 已提交
1107
	spin_unlock(&gl->gl_spin);
1108 1109
	if (likely(fast_path))
		return;
1110 1111 1112

	gfs2_glock_hold(gl);
	if (test_bit(GLF_PENDING_DEMOTE, &gl->gl_flags) &&
1113 1114 1115
	    !test_bit(GLF_DEMOTE, &gl->gl_flags) &&
	    gl->gl_name.ln_type == LM_TYPE_INODE)
		delay = gl->gl_hold_time;
1116 1117
	if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
		gfs2_glock_put(gl);
D
David Teigland 已提交
1118 1119
}

A
Abhijith Das 已提交
1120 1121 1122 1123
void gfs2_glock_dq_wait(struct gfs2_holder *gh)
{
	struct gfs2_glock *gl = gh->gh_gl;
	gfs2_glock_dq(gh);
1124 1125
	might_sleep();
	wait_on_bit(&gl->gl_flags, GLF_DEMOTE, gfs2_glock_demote_wait, TASK_UNINTERRUPTIBLE);
A
Abhijith Das 已提交
1126 1127
}

D
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1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145
/**
 * gfs2_glock_dq_uninit - dequeue a holder from a glock and initialize it
 * @gh: the holder structure
 *
 */

void gfs2_glock_dq_uninit(struct gfs2_holder *gh)
{
	gfs2_glock_dq(gh);
	gfs2_holder_uninit(gh);
}

/**
 * gfs2_glock_nq_num - acquire a glock based on lock number
 * @sdp: the filesystem
 * @number: the lock number
 * @glops: the glock operations for the type of glock
 * @state: the state to acquire the glock in
L
Lucas De Marchi 已提交
1146
 * @flags: modifier flags for the acquisition
D
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1147 1148 1149 1150 1151
 * @gh: the struct gfs2_holder
 *
 * Returns: errno
 */

1152
int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1153 1154
		      const struct gfs2_glock_operations *glops,
		      unsigned int state, int flags, struct gfs2_holder *gh)
D
David Teigland 已提交
1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176
{
	struct gfs2_glock *gl;
	int error;

	error = gfs2_glock_get(sdp, number, glops, CREATE, &gl);
	if (!error) {
		error = gfs2_glock_nq_init(gl, state, flags, gh);
		gfs2_glock_put(gl);
	}

	return error;
}

/**
 * glock_compare - Compare two struct gfs2_glock structures for sorting
 * @arg_a: the first structure
 * @arg_b: the second structure
 *
 */

static int glock_compare(const void *arg_a, const void *arg_b)
{
1177 1178 1179 1180
	const struct gfs2_holder *gh_a = *(const struct gfs2_holder **)arg_a;
	const struct gfs2_holder *gh_b = *(const struct gfs2_holder **)arg_b;
	const struct lm_lockname *a = &gh_a->gh_gl->gl_name;
	const struct lm_lockname *b = &gh_b->gh_gl->gl_name;
D
David Teigland 已提交
1181 1182

	if (a->ln_number > b->ln_number)
1183 1184 1185
		return 1;
	if (a->ln_number < b->ln_number)
		return -1;
1186
	BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1187
	return 0;
D
David Teigland 已提交
1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235
}

/**
 * nq_m_sync - synchonously acquire more than one glock in deadlock free order
 * @num_gh: the number of structures
 * @ghs: an array of struct gfs2_holder structures
 *
 * Returns: 0 on success (all glocks acquired),
 *          errno on failure (no glocks acquired)
 */

static int nq_m_sync(unsigned int num_gh, struct gfs2_holder *ghs,
		     struct gfs2_holder **p)
{
	unsigned int x;
	int error = 0;

	for (x = 0; x < num_gh; x++)
		p[x] = &ghs[x];

	sort(p, num_gh, sizeof(struct gfs2_holder *), glock_compare, NULL);

	for (x = 0; x < num_gh; x++) {
		p[x]->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);

		error = gfs2_glock_nq(p[x]);
		if (error) {
			while (x--)
				gfs2_glock_dq(p[x]);
			break;
		}
	}

	return error;
}

/**
 * gfs2_glock_nq_m - acquire multiple glocks
 * @num_gh: the number of structures
 * @ghs: an array of struct gfs2_holder structures
 *
 *
 * Returns: 0 on success (all glocks acquired),
 *          errno on failure (no glocks acquired)
 */

int gfs2_glock_nq_m(unsigned int num_gh, struct gfs2_holder *ghs)
{
1236 1237
	struct gfs2_holder *tmp[4];
	struct gfs2_holder **pph = tmp;
D
David Teigland 已提交
1238 1239
	int error = 0;

1240 1241
	switch(num_gh) {
	case 0:
D
David Teigland 已提交
1242
		return 0;
1243
	case 1:
D
David Teigland 已提交
1244 1245
		ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
		return gfs2_glock_nq(ghs);
1246 1247
	default:
		if (num_gh <= 4)
D
David Teigland 已提交
1248
			break;
1249 1250 1251
		pph = kmalloc(num_gh * sizeof(struct gfs2_holder *), GFP_NOFS);
		if (!pph)
			return -ENOMEM;
D
David Teigland 已提交
1252 1253
	}

1254
	error = nq_m_sync(num_gh, ghs, pph);
D
David Teigland 已提交
1255

1256 1257
	if (pph != tmp)
		kfree(pph);
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1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270

	return error;
}

/**
 * gfs2_glock_dq_m - release multiple glocks
 * @num_gh: the number of structures
 * @ghs: an array of struct gfs2_holder structures
 *
 */

void gfs2_glock_dq_m(unsigned int num_gh, struct gfs2_holder *ghs)
{
1271 1272
	while (num_gh--)
		gfs2_glock_dq(&ghs[num_gh]);
D
David Teigland 已提交
1273 1274
}

1275
void gfs2_glock_cb(struct gfs2_glock *gl, unsigned int state)
1276
{
1277 1278 1279
	unsigned long delay = 0;
	unsigned long holdtime;
	unsigned long now = jiffies;
D
David Teigland 已提交
1280

1281
	gfs2_glock_hold(gl);
1282 1283 1284
	holdtime = gl->gl_tchange + gl->gl_hold_time;
	if (test_bit(GLF_QUEUED, &gl->gl_flags) &&
	    gl->gl_name.ln_type == LM_TYPE_INODE) {
1285 1286 1287
		if (time_before(now, holdtime))
			delay = holdtime - now;
		if (test_bit(GLF_REPLY_PENDING, &gl->gl_flags))
1288
			delay = gl->gl_hold_time;
1289
	}
D
David Teigland 已提交
1290

1291
	spin_lock(&gl->gl_spin);
1292
	handle_callback(gl, state, delay, true);
1293
	spin_unlock(&gl->gl_spin);
1294 1295
	if (queue_delayed_work(glock_workqueue, &gl->gl_work, delay) == 0)
		gfs2_glock_put(gl);
D
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1296 1297
}

1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327
/**
 * gfs2_should_freeze - Figure out if glock should be frozen
 * @gl: The glock in question
 *
 * Glocks are not frozen if (a) the result of the dlm operation is
 * an error, (b) the locking operation was an unlock operation or
 * (c) if there is a "noexp" flagged request anywhere in the queue
 *
 * Returns: 1 if freezing should occur, 0 otherwise
 */

static int gfs2_should_freeze(const struct gfs2_glock *gl)
{
	const struct gfs2_holder *gh;

	if (gl->gl_reply & ~LM_OUT_ST_MASK)
		return 0;
	if (gl->gl_target == LM_ST_UNLOCKED)
		return 0;

	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
		if (test_bit(HIF_HOLDER, &gh->gh_iflags))
			continue;
		if (LM_FLAG_NOEXP & gh->gh_flags)
			return 0;
	}

	return 1;
}

D
David Teigland 已提交
1328
/**
1329 1330 1331
 * gfs2_glock_complete - Callback used by locking
 * @gl: Pointer to the glock
 * @ret: The return value from the dlm
D
David Teigland 已提交
1332
 *
1333 1334
 * The gl_reply field is under the gl_spin lock so that it is ok
 * to use a bitfield shared with other glock state fields.
D
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1335 1336
 */

1337
void gfs2_glock_complete(struct gfs2_glock *gl, int ret)
D
David Teigland 已提交
1338
{
1339
	struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
1340

1341
	spin_lock(&gl->gl_spin);
1342
	gl->gl_reply = ret;
1343

1344
	if (unlikely(test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags))) {
1345
		if (gfs2_should_freeze(gl)) {
1346
			set_bit(GLF_FROZEN, &gl->gl_flags);
1347
			spin_unlock(&gl->gl_spin);
D
David Teigland 已提交
1348
			return;
1349
		}
D
David Teigland 已提交
1350
	}
1351

S
Steven Whitehouse 已提交
1352
	gl->gl_lockref.count++;
1353
	set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
S
Steven Whitehouse 已提交
1354 1355
	spin_unlock(&gl->gl_spin);

1356 1357
	if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
		gfs2_glock_put(gl);
D
David Teigland 已提交
1358 1359
}

1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399
static int glock_cmp(void *priv, struct list_head *a, struct list_head *b)
{
	struct gfs2_glock *gla, *glb;

	gla = list_entry(a, struct gfs2_glock, gl_lru);
	glb = list_entry(b, struct gfs2_glock, gl_lru);

	if (gla->gl_name.ln_number > glb->gl_name.ln_number)
		return 1;
	if (gla->gl_name.ln_number < glb->gl_name.ln_number)
		return -1;

	return 0;
}

/**
 * gfs2_dispose_glock_lru - Demote a list of glocks
 * @list: The list to dispose of
 *
 * Disposing of glocks may involve disk accesses, so that here we sort
 * the glocks by number (i.e. disk location of the inodes) so that if
 * there are any such accesses, they'll be sent in order (mostly).
 *
 * Must be called under the lru_lock, but may drop and retake this
 * lock. While the lru_lock is dropped, entries may vanish from the
 * list, but no new entries will appear on the list (since it is
 * private)
 */

static void gfs2_dispose_glock_lru(struct list_head *list)
__releases(&lru_lock)
__acquires(&lru_lock)
{
	struct gfs2_glock *gl;

	list_sort(NULL, list, glock_cmp);

	while(!list_empty(list)) {
		gl = list_entry(list->next, struct gfs2_glock, gl_lru);
		list_del_init(&gl->gl_lru);
S
Steven Whitehouse 已提交
1400 1401 1402 1403 1404
		if (!spin_trylock(&gl->gl_spin)) {
			list_add(&gl->gl_lru, &lru_list);
			atomic_inc(&lru_count);
			continue;
		}
1405 1406
		clear_bit(GLF_LRU, &gl->gl_flags);
		spin_unlock(&lru_lock);
S
Steven Whitehouse 已提交
1407
		gl->gl_lockref.count++;
1408
		if (demote_ok(gl))
1409
			handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1410 1411
		WARN_ON(!test_and_clear_bit(GLF_LOCK, &gl->gl_flags));
		if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
S
Steven Whitehouse 已提交
1412
			gl->gl_lockref.count--;
1413 1414 1415 1416 1417
		spin_unlock(&gl->gl_spin);
		spin_lock(&lru_lock);
	}
}

1418 1419 1420 1421
/**
 * gfs2_scan_glock_lru - Scan the LRU looking for locks to demote
 * @nr: The number of entries to scan
 *
1422 1423 1424
 * This function selects the entries on the LRU which are able to
 * be demoted, and then kicks off the process by calling
 * gfs2_dispose_glock_lru() above.
1425
 */
D
David Teigland 已提交
1426

1427
static long gfs2_scan_glock_lru(int nr)
D
David Teigland 已提交
1428 1429
{
	struct gfs2_glock *gl;
1430
	LIST_HEAD(skipped);
1431
	LIST_HEAD(dispose);
1432
	long freed = 0;
D
David Teigland 已提交
1433

1434
	spin_lock(&lru_lock);
1435
	while ((nr-- >= 0) && !list_empty(&lru_list)) {
1436 1437 1438 1439
		gl = list_entry(lru_list.next, struct gfs2_glock, gl_lru);

		/* Test for being demotable */
		if (!test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
1440 1441
			list_move(&gl->gl_lru, &dispose);
			atomic_dec(&lru_count);
1442
			freed++;
S
Steven Whitehouse 已提交
1443
			continue;
1444
		}
1445 1446

		list_move(&gl->gl_lru, &skipped);
D
David Teigland 已提交
1447
	}
1448
	list_splice(&skipped, &lru_list);
1449 1450
	if (!list_empty(&dispose))
		gfs2_dispose_glock_lru(&dispose);
1451
	spin_unlock(&lru_lock);
1452 1453

	return freed;
1454 1455
}

1456 1457
static unsigned long gfs2_glock_shrink_scan(struct shrinker *shrink,
					    struct shrink_control *sc)
1458
{
1459 1460 1461 1462
	if (!(sc->gfp_mask & __GFP_FS))
		return SHRINK_STOP;
	return gfs2_scan_glock_lru(sc->nr_to_scan);
}
1463

1464 1465 1466
static unsigned long gfs2_glock_shrink_count(struct shrinker *shrink,
					     struct shrink_control *sc)
{
1467
	return vfs_pressure_ratio(atomic_read(&lru_count));
D
David Teigland 已提交
1468 1469
}

1470 1471
static struct shrinker glock_shrinker = {
	.seeks = DEFAULT_SEEKS,
1472 1473
	.count_objects = gfs2_glock_shrink_count,
	.scan_objects = gfs2_glock_shrink_scan,
1474 1475
};

D
David Teigland 已提交
1476 1477 1478 1479 1480 1481 1482 1483
/**
 * examine_bucket - Call a function for glock in a hash bucket
 * @examiner: the function
 * @sdp: the filesystem
 * @bucket: the bucket
 *
 */

1484
static void examine_bucket(glock_examiner examiner, const struct gfs2_sbd *sdp,
1485
			  unsigned int hash)
D
David Teigland 已提交
1486
{
1487 1488 1489
	struct gfs2_glock *gl;
	struct hlist_bl_head *head = &gl_hash_table[hash];
	struct hlist_bl_node *pos;
D
David Teigland 已提交
1490

1491 1492
	rcu_read_lock();
	hlist_bl_for_each_entry_rcu(gl, pos, head, gl_list) {
S
Steven Whitehouse 已提交
1493
		if ((gl->gl_sbd == sdp) && lockref_get_not_dead(&gl->gl_lockref))
1494
			examiner(gl);
D
David Teigland 已提交
1495
	}
1496
	rcu_read_unlock();
1497
	cond_resched();
1498 1499 1500 1501 1502 1503 1504 1505
}

static void glock_hash_walk(glock_examiner examiner, const struct gfs2_sbd *sdp)
{
	unsigned x;

	for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
		examine_bucket(examiner, sdp, x);
D
David Teigland 已提交
1506 1507
}

1508 1509 1510 1511 1512 1513 1514 1515 1516 1517

/**
 * thaw_glock - thaw out a glock which has an unprocessed reply waiting
 * @gl: The glock to thaw
 *
 */

static void thaw_glock(struct gfs2_glock *gl)
{
	if (!test_and_clear_bit(GLF_FROZEN, &gl->gl_flags))
1518
		goto out;
1519
	set_bit(GLF_REPLY_PENDING, &gl->gl_flags);
1520 1521
	if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0) {
out:
1522
		gfs2_glock_put(gl);
1523
	}
1524 1525
}

D
David Teigland 已提交
1526 1527 1528 1529 1530 1531 1532 1533
/**
 * clear_glock - look at a glock and see if we can free it from glock cache
 * @gl: the glock to look at
 *
 */

static void clear_glock(struct gfs2_glock *gl)
{
1534
	gfs2_glock_remove_from_lru(gl);
D
David Teigland 已提交
1535

1536
	spin_lock(&gl->gl_spin);
1537
	if (gl->gl_state != LM_ST_UNLOCKED)
1538
		handle_callback(gl, LM_ST_UNLOCKED, 0, false);
1539 1540 1541
	spin_unlock(&gl->gl_spin);
	if (queue_delayed_work(glock_workqueue, &gl->gl_work, 0) == 0)
		gfs2_glock_put(gl);
D
David Teigland 已提交
1542 1543
}

1544 1545 1546 1547 1548 1549 1550 1551
/**
 * gfs2_glock_thaw - Thaw any frozen glocks
 * @sdp: The super block
 *
 */

void gfs2_glock_thaw(struct gfs2_sbd *sdp)
{
1552 1553
	glock_hash_walk(thaw_glock, sdp);
}
1554

1555 1556 1557 1558
static int dump_glock(struct seq_file *seq, struct gfs2_glock *gl)
{
	int ret;
	spin_lock(&gl->gl_spin);
1559
	ret = gfs2_dump_glock(seq, gl);
1560 1561 1562 1563 1564 1565 1566
	spin_unlock(&gl->gl_spin);
	return ret;
}

static void dump_glock_func(struct gfs2_glock *gl)
{
	dump_glock(NULL, gl);
1567 1568
}

D
David Teigland 已提交
1569 1570 1571 1572 1573
/**
 * gfs2_gl_hash_clear - Empty out the glock hash table
 * @sdp: the filesystem
 * @wait: wait until it's all gone
 *
1574
 * Called when unmounting the filesystem.
D
David Teigland 已提交
1575 1576
 */

1577
void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
D
David Teigland 已提交
1578
{
1579
	set_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags);
1580
	flush_workqueue(glock_workqueue);
1581
	glock_hash_walk(clear_glock, sdp);
1582 1583
	flush_workqueue(glock_workqueue);
	wait_event(sdp->sd_glock_wait, atomic_read(&sdp->sd_glock_disposal) == 0);
1584
	glock_hash_walk(dump_glock_func, sdp);
D
David Teigland 已提交
1585 1586
}

1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600
void gfs2_glock_finish_truncate(struct gfs2_inode *ip)
{
	struct gfs2_glock *gl = ip->i_gl;
	int ret;

	ret = gfs2_truncatei_resume(ip);
	gfs2_assert_withdraw(gl->gl_sbd, ret == 0);

	spin_lock(&gl->gl_spin);
	clear_bit(GLF_LOCK, &gl->gl_flags);
	run_queue(gl, 1);
	spin_unlock(&gl->gl_spin);
}

1601
static const char *state2str(unsigned state)
1602
{
1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625
	switch(state) {
	case LM_ST_UNLOCKED:
		return "UN";
	case LM_ST_SHARED:
		return "SH";
	case LM_ST_DEFERRED:
		return "DF";
	case LM_ST_EXCLUSIVE:
		return "EX";
	}
	return "??";
}

static const char *hflags2str(char *buf, unsigned flags, unsigned long iflags)
{
	char *p = buf;
	if (flags & LM_FLAG_TRY)
		*p++ = 't';
	if (flags & LM_FLAG_TRY_1CB)
		*p++ = 'T';
	if (flags & LM_FLAG_NOEXP)
		*p++ = 'e';
	if (flags & LM_FLAG_ANY)
1626
		*p++ = 'A';
1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642
	if (flags & LM_FLAG_PRIORITY)
		*p++ = 'p';
	if (flags & GL_ASYNC)
		*p++ = 'a';
	if (flags & GL_EXACT)
		*p++ = 'E';
	if (flags & GL_NOCACHE)
		*p++ = 'c';
	if (test_bit(HIF_HOLDER, &iflags))
		*p++ = 'H';
	if (test_bit(HIF_WAIT, &iflags))
		*p++ = 'W';
	if (test_bit(HIF_FIRST, &iflags))
		*p++ = 'F';
	*p = 0;
	return buf;
1643 1644
}

D
David Teigland 已提交
1645 1646
/**
 * dump_holder - print information about a glock holder
1647
 * @seq: the seq_file struct
D
David Teigland 已提交
1648 1649 1650 1651 1652
 * @gh: the glock holder
 *
 * Returns: 0 on success, -ENOBUFS when we run out of space
 */

1653
static int dump_holder(struct seq_file *seq, const struct gfs2_holder *gh)
D
David Teigland 已提交
1654
{
1655 1656
	struct task_struct *gh_owner = NULL;
	char flags_buf[32];
D
David Teigland 已提交
1657

1658
	if (gh->gh_owner_pid)
1659
		gh_owner = pid_task(gh->gh_owner_pid, PIDTYPE_PID);
1660 1661 1662 1663 1664 1665 1666
	gfs2_print_dbg(seq, " H: s:%s f:%s e:%d p:%ld [%s] %pS\n",
		       state2str(gh->gh_state),
		       hflags2str(flags_buf, gh->gh_flags, gh->gh_iflags),
		       gh->gh_error,
		       gh->gh_owner_pid ? (long)pid_nr(gh->gh_owner_pid) : -1,
		       gh_owner ? gh_owner->comm : "(ended)",
		       (void *)gh->gh_ip);
1667
	return 0;
D
David Teigland 已提交
1668 1669
}

1670
static const char *gflags2str(char *buf, const struct gfs2_glock *gl)
1671
{
1672
	const unsigned long *gflags = &gl->gl_flags;
1673
	char *p = buf;
1674

1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690
	if (test_bit(GLF_LOCK, gflags))
		*p++ = 'l';
	if (test_bit(GLF_DEMOTE, gflags))
		*p++ = 'D';
	if (test_bit(GLF_PENDING_DEMOTE, gflags))
		*p++ = 'd';
	if (test_bit(GLF_DEMOTE_IN_PROGRESS, gflags))
		*p++ = 'p';
	if (test_bit(GLF_DIRTY, gflags))
		*p++ = 'y';
	if (test_bit(GLF_LFLUSH, gflags))
		*p++ = 'f';
	if (test_bit(GLF_INVALIDATE_IN_PROGRESS, gflags))
		*p++ = 'i';
	if (test_bit(GLF_REPLY_PENDING, gflags))
		*p++ = 'r';
1691
	if (test_bit(GLF_INITIAL, gflags))
1692
		*p++ = 'I';
1693 1694
	if (test_bit(GLF_FROZEN, gflags))
		*p++ = 'F';
1695 1696
	if (test_bit(GLF_QUEUED, gflags))
		*p++ = 'q';
1697 1698 1699 1700
	if (test_bit(GLF_LRU, gflags))
		*p++ = 'L';
	if (gl->gl_object)
		*p++ = 'o';
1701 1702
	if (test_bit(GLF_BLOCKING, gflags))
		*p++ = 'b';
1703 1704
	*p = 0;
	return buf;
D
David Teigland 已提交
1705 1706 1707
}

/**
1708
 * gfs2_dump_glock - print information about a glock
1709
 * @seq: The seq_file struct
D
David Teigland 已提交
1710
 * @gl: the glock
1711 1712 1713 1714 1715 1716 1717 1718 1719 1720
 *
 * The file format is as follows:
 * One line per object, capital letters are used to indicate objects
 * G = glock, I = Inode, R = rgrp, H = holder. Glocks are not indented,
 * other objects are indented by a single space and follow the glock to
 * which they are related. Fields are indicated by lower case letters
 * followed by a colon and the field value, except for strings which are in
 * [] so that its possible to see if they are composed of spaces for
 * example. The field's are n = number (id of the object), f = flags,
 * t = type, s = state, r = refcount, e = error, p = pid.
D
David Teigland 已提交
1721 1722 1723 1724
 *
 * Returns: 0 on success, -ENOBUFS when we run out of space
 */

1725
int gfs2_dump_glock(struct seq_file *seq, const struct gfs2_glock *gl)
D
David Teigland 已提交
1726
{
1727 1728 1729 1730 1731
	const struct gfs2_glock_operations *glops = gl->gl_ops;
	unsigned long long dtime;
	const struct gfs2_holder *gh;
	char gflags_buf[32];
	int error = 0;
D
David Teigland 已提交
1732

1733 1734 1735 1736
	dtime = jiffies - gl->gl_demote_time;
	dtime *= 1000000/HZ; /* demote time in uSec */
	if (!test_bit(GLF_DEMOTE, &gl->gl_flags))
		dtime = 0;
1737
	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",
1738 1739 1740
		  state2str(gl->gl_state),
		  gl->gl_name.ln_type,
		  (unsigned long long)gl->gl_name.ln_number,
1741
		  gflags2str(gflags_buf, gl),
1742 1743 1744
		  state2str(gl->gl_target),
		  state2str(gl->gl_demote_state), dtime,
		  atomic_read(&gl->gl_ail_count),
1745
		  atomic_read(&gl->gl_revokes),
S
Steven Whitehouse 已提交
1746
		  (int)gl->gl_lockref.count, gl->gl_hold_time);
D
David Teigland 已提交
1747 1748

	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1749
		error = dump_holder(seq, gh);
D
David Teigland 已提交
1750 1751 1752
		if (error)
			goto out;
	}
1753 1754
	if (gl->gl_state != LM_ST_UNLOCKED && glops->go_dump)
		error = glops->go_dump(seq, gl);
1755
out:
D
David Teigland 已提交
1756 1757 1758
	return error;
}

1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814
static int gfs2_glstats_seq_show(struct seq_file *seq, void *iter_ptr)
{
	struct gfs2_glock *gl = iter_ptr;

	seq_printf(seq, "G: n:%u/%llx rtt:%lld/%lld rttb:%lld/%lld irt:%lld/%lld dcnt: %lld qcnt: %lld\n",
		   gl->gl_name.ln_type,
		   (unsigned long long)gl->gl_name.ln_number,
		   (long long)gl->gl_stats.stats[GFS2_LKS_SRTT],
		   (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVAR],
		   (long long)gl->gl_stats.stats[GFS2_LKS_SRTTB],
		   (long long)gl->gl_stats.stats[GFS2_LKS_SRTTVARB],
		   (long long)gl->gl_stats.stats[GFS2_LKS_SIRT],
		   (long long)gl->gl_stats.stats[GFS2_LKS_SIRTVAR],
		   (long long)gl->gl_stats.stats[GFS2_LKS_DCOUNT],
		   (long long)gl->gl_stats.stats[GFS2_LKS_QCOUNT]);
	return 0;
}

static const char *gfs2_gltype[] = {
	"type",
	"reserved",
	"nondisk",
	"inode",
	"rgrp",
	"meta",
	"iopen",
	"flock",
	"plock",
	"quota",
	"journal",
};

static const char *gfs2_stype[] = {
	[GFS2_LKS_SRTT]		= "srtt",
	[GFS2_LKS_SRTTVAR]	= "srttvar",
	[GFS2_LKS_SRTTB]	= "srttb",
	[GFS2_LKS_SRTTVARB]	= "srttvarb",
	[GFS2_LKS_SIRT]		= "sirt",
	[GFS2_LKS_SIRTVAR]	= "sirtvar",
	[GFS2_LKS_DCOUNT]	= "dlm",
	[GFS2_LKS_QCOUNT]	= "queue",
};

#define GFS2_NR_SBSTATS (ARRAY_SIZE(gfs2_gltype) * ARRAY_SIZE(gfs2_stype))

static int gfs2_sbstats_seq_show(struct seq_file *seq, void *iter_ptr)
{
	struct gfs2_glock_iter *gi = seq->private;
	struct gfs2_sbd *sdp = gi->sdp;
	unsigned index = gi->hash >> 3;
	unsigned subindex = gi->hash & 0x07;
	s64 value;
	int i;

	if (index == 0 && subindex != 0)
		return 0;
1815

1816 1817
	seq_printf(seq, "%-10s %8s:", gfs2_gltype[index],
		   (index == 0) ? "cpu": gfs2_stype[subindex]);
D
David Teigland 已提交
1818

1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830
	for_each_possible_cpu(i) {
                const struct gfs2_pcpu_lkstats *lkstats = per_cpu_ptr(sdp->sd_lkstats, i);
		if (index == 0) {
			value = i;
		} else {
			value = lkstats->lkstats[index - 1].stats[subindex];
		}
		seq_printf(seq, " %15lld", (long long)value);
	}
	seq_putc(seq, '\n');
	return 0;
}
1831

1832 1833 1834 1835
int __init gfs2_glock_init(void)
{
	unsigned i;
	for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
1836
		INIT_HLIST_BL_HEAD(&gl_hash_table[i]);
1837
	}
1838

1839
	glock_workqueue = alloc_workqueue("glock_workqueue", WQ_MEM_RECLAIM |
1840
					  WQ_HIGHPRI | WQ_FREEZABLE, 0);
1841 1842
	if (!glock_workqueue)
		return -ENOMEM;
1843
	gfs2_delete_workqueue = alloc_workqueue("delete_workqueue",
1844
						WQ_MEM_RECLAIM | WQ_FREEZABLE,
1845
						0);
1846
	if (!gfs2_delete_workqueue) {
1847
		destroy_workqueue(glock_workqueue);
1848
		return -ENOMEM;
1849
	}
1850 1851

	register_shrinker(&glock_shrinker);
1852

1853 1854 1855
	return 0;
}

1856 1857
void gfs2_glock_exit(void)
{
1858
	unregister_shrinker(&glock_shrinker);
1859
	destroy_workqueue(glock_workqueue);
1860
	destroy_workqueue(gfs2_delete_workqueue);
1861 1862
}

1863 1864 1865 1866 1867 1868 1869 1870
static inline struct gfs2_glock *glock_hash_chain(unsigned hash)
{
	return hlist_bl_entry(hlist_bl_first_rcu(&gl_hash_table[hash]),
			      struct gfs2_glock, gl_list);
}

static inline struct gfs2_glock *glock_hash_next(struct gfs2_glock *gl)
{
1871
	return hlist_bl_entry(rcu_dereference(gl->gl_list.next),
1872 1873 1874
			      struct gfs2_glock, gl_list);
}

1875
static int gfs2_glock_iter_next(struct gfs2_glock_iter *gi)
1876
{
1877 1878
	struct gfs2_glock *gl;

1879 1880 1881 1882
	do {
		gl = gi->gl;
		if (gl) {
			gi->gl = glock_hash_next(gl);
1883
			gi->nhash++;
1884
		} else {
1885 1886 1887 1888
			if (gi->hash >= GFS2_GL_HASH_SIZE) {
				rcu_read_unlock();
				return 1;
			}
1889
			gi->gl = glock_hash_chain(gi->hash);
1890
			gi->nhash = 0;
1891 1892 1893 1894 1895 1896 1897 1898
		}
		while (gi->gl == NULL) {
			gi->hash++;
			if (gi->hash >= GFS2_GL_HASH_SIZE) {
				rcu_read_unlock();
				return 1;
			}
			gi->gl = glock_hash_chain(gi->hash);
1899
			gi->nhash = 0;
1900 1901
		}
	/* Skip entries for other sb and dead entries */
S
Steven Whitehouse 已提交
1902
	} while (gi->sdp != gi->gl->gl_sbd || __lockref_is_dead(&gl->gl_lockref));
1903

1904 1905 1906
	return 0;
}

1907
static void *gfs2_glock_seq_start(struct seq_file *seq, loff_t *pos)
1908
{
1909
	struct gfs2_glock_iter *gi = seq->private;
1910 1911
	loff_t n = *pos;

1912 1913 1914 1915 1916 1917
	if (gi->last_pos <= *pos)
		n = gi->nhash + (*pos - gi->last_pos);
	else
		gi->hash = 0;

	gi->nhash = 0;
1918
	rcu_read_lock();
1919

1920
	do {
1921
		if (gfs2_glock_iter_next(gi))
1922
			return NULL;
1923
	} while (n--);
1924

1925
	gi->last_pos = *pos;
1926
	return gi->gl;
1927 1928
}

1929
static void *gfs2_glock_seq_next(struct seq_file *seq, void *iter_ptr,
1930 1931
				 loff_t *pos)
{
1932
	struct gfs2_glock_iter *gi = seq->private;
1933 1934

	(*pos)++;
1935
	gi->last_pos = *pos;
1936
	if (gfs2_glock_iter_next(gi))
1937 1938
		return NULL;

1939
	return gi->gl;
1940 1941
}

1942
static void gfs2_glock_seq_stop(struct seq_file *seq, void *iter_ptr)
1943
{
1944
	struct gfs2_glock_iter *gi = seq->private;
1945 1946 1947 1948

	if (gi->gl)
		rcu_read_unlock();
	gi->gl = NULL;
1949 1950
}

1951
static int gfs2_glock_seq_show(struct seq_file *seq, void *iter_ptr)
1952
{
1953
	return dump_glock(seq, iter_ptr);
1954 1955
}

1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984
static void *gfs2_sbstats_seq_start(struct seq_file *seq, loff_t *pos)
{
	struct gfs2_glock_iter *gi = seq->private;

	gi->hash = *pos;
	if (*pos >= GFS2_NR_SBSTATS)
		return NULL;
	preempt_disable();
	return SEQ_START_TOKEN;
}

static void *gfs2_sbstats_seq_next(struct seq_file *seq, void *iter_ptr,
				   loff_t *pos)
{
	struct gfs2_glock_iter *gi = seq->private;
	(*pos)++;
	gi->hash++;
	if (gi->hash >= GFS2_NR_SBSTATS) {
		preempt_enable();
		return NULL;
	}
	return SEQ_START_TOKEN;
}

static void gfs2_sbstats_seq_stop(struct seq_file *seq, void *iter_ptr)
{
	preempt_enable();
}

1985
static const struct seq_operations gfs2_glock_seq_ops = {
1986 1987 1988 1989 1990 1991
	.start = gfs2_glock_seq_start,
	.next  = gfs2_glock_seq_next,
	.stop  = gfs2_glock_seq_stop,
	.show  = gfs2_glock_seq_show,
};

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005
static const struct seq_operations gfs2_glstats_seq_ops = {
	.start = gfs2_glock_seq_start,
	.next  = gfs2_glock_seq_next,
	.stop  = gfs2_glock_seq_stop,
	.show  = gfs2_glstats_seq_show,
};

static const struct seq_operations gfs2_sbstats_seq_ops = {
	.start = gfs2_sbstats_seq_start,
	.next  = gfs2_sbstats_seq_next,
	.stop  = gfs2_sbstats_seq_stop,
	.show  = gfs2_sbstats_seq_show,
};

2006 2007
#define GFS2_SEQ_GOODSIZE min(PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER, 65536UL)

2008
static int gfs2_glocks_open(struct inode *inode, struct file *file)
2009
{
2010 2011 2012 2013 2014 2015
	int ret = seq_open_private(file, &gfs2_glock_seq_ops,
				   sizeof(struct gfs2_glock_iter));
	if (ret == 0) {
		struct seq_file *seq = file->private_data;
		struct gfs2_glock_iter *gi = seq->private;
		gi->sdp = inode->i_private;
2016
		seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2017
		if (seq->buf)
2018
			seq->size = GFS2_SEQ_GOODSIZE;
2019 2020
	}
	return ret;
2021 2022
}

2023 2024 2025 2026 2027 2028 2029 2030
static int gfs2_glstats_open(struct inode *inode, struct file *file)
{
	int ret = seq_open_private(file, &gfs2_glstats_seq_ops,
				   sizeof(struct gfs2_glock_iter));
	if (ret == 0) {
		struct seq_file *seq = file->private_data;
		struct gfs2_glock_iter *gi = seq->private;
		gi->sdp = inode->i_private;
2031
		seq->buf = kmalloc(GFS2_SEQ_GOODSIZE, GFP_KERNEL | __GFP_NOWARN);
2032
		if (seq->buf)
2033
			seq->size = GFS2_SEQ_GOODSIZE;
2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058
	}
	return ret;
}

static int gfs2_sbstats_open(struct inode *inode, struct file *file)
{
	int ret = seq_open_private(file, &gfs2_sbstats_seq_ops,
				   sizeof(struct gfs2_glock_iter));
	if (ret == 0) {
		struct seq_file *seq = file->private_data;
		struct gfs2_glock_iter *gi = seq->private;
		gi->sdp = inode->i_private;
	}
	return ret;
}

static const struct file_operations gfs2_glocks_fops = {
	.owner   = THIS_MODULE,
	.open    = gfs2_glocks_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release_private,
};

static const struct file_operations gfs2_glstats_fops = {
2059
	.owner   = THIS_MODULE,
2060 2061 2062 2063 2064 2065 2066 2067 2068
	.open    = gfs2_glstats_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release_private,
};

static const struct file_operations gfs2_sbstats_fops = {
	.owner   = THIS_MODULE,
	.open	 = gfs2_sbstats_open,
2069 2070
	.read    = seq_read,
	.llseek  = seq_lseek,
2071
	.release = seq_release_private,
2072 2073 2074 2075
};

int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
{
R
Robert Peterson 已提交
2076 2077 2078 2079 2080 2081
	sdp->debugfs_dir = debugfs_create_dir(sdp->sd_table_name, gfs2_root);
	if (!sdp->debugfs_dir)
		return -ENOMEM;
	sdp->debugfs_dentry_glocks = debugfs_create_file("glocks",
							 S_IFREG | S_IRUGO,
							 sdp->debugfs_dir, sdp,
2082
							 &gfs2_glocks_fops);
R
Robert Peterson 已提交
2083
	if (!sdp->debugfs_dentry_glocks)
2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098
		goto fail;

	sdp->debugfs_dentry_glstats = debugfs_create_file("glstats",
							S_IFREG | S_IRUGO,
							sdp->debugfs_dir, sdp,
							&gfs2_glstats_fops);
	if (!sdp->debugfs_dentry_glstats)
		goto fail;

	sdp->debugfs_dentry_sbstats = debugfs_create_file("sbstats",
							S_IFREG | S_IRUGO,
							sdp->debugfs_dir, sdp,
							&gfs2_sbstats_fops);
	if (!sdp->debugfs_dentry_sbstats)
		goto fail;
2099 2100

	return 0;
2101 2102 2103
fail:
	gfs2_delete_debugfs_file(sdp);
	return -ENOMEM;
2104 2105 2106 2107
}

void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
{
2108
	if (sdp->debugfs_dir) {
R
Robert Peterson 已提交
2109 2110 2111 2112
		if (sdp->debugfs_dentry_glocks) {
			debugfs_remove(sdp->debugfs_dentry_glocks);
			sdp->debugfs_dentry_glocks = NULL;
		}
2113 2114 2115 2116 2117 2118 2119 2120
		if (sdp->debugfs_dentry_glstats) {
			debugfs_remove(sdp->debugfs_dentry_glstats);
			sdp->debugfs_dentry_glstats = NULL;
		}
		if (sdp->debugfs_dentry_sbstats) {
			debugfs_remove(sdp->debugfs_dentry_sbstats);
			sdp->debugfs_dentry_sbstats = NULL;
		}
R
Robert Peterson 已提交
2121 2122 2123
		debugfs_remove(sdp->debugfs_dir);
		sdp->debugfs_dir = NULL;
	}
2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134
}

int gfs2_register_debugfs(void)
{
	gfs2_root = debugfs_create_dir("gfs2", NULL);
	return gfs2_root ? 0 : -ENOMEM;
}

void gfs2_unregister_debugfs(void)
{
	debugfs_remove(gfs2_root);
R
Robert Peterson 已提交
2135
	gfs2_root = NULL;
2136
}