glock.c 47.0 KB
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/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
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 * Copyright (C) 2004-2006 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/completion.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/lm_interface.h>
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#include <linux/wait.h>
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#include <linux/module.h>
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#include <linux/rwsem.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 "gfs2.h"
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#include "incore.h"
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#include "glock.h"
#include "glops.h"
#include "inode.h"
#include "lm.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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struct gfs2_gl_hash_bucket {
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        struct hlist_head hb_list;
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};

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struct glock_iter {
	int hash;                     /* hash bucket index         */
	struct gfs2_sbd *sdp;         /* incore superblock         */
	struct gfs2_glock *gl;        /* current glock struct      */
	struct hlist_head *hb_list;   /* current hash bucket ptr   */
	struct seq_file *seq;         /* sequence file for debugfs */
	char string[512];             /* scratch space             */
};

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

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static int gfs2_dump_lockstate(struct gfs2_sbd *sdp);
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static void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh);
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static void gfs2_glock_drop_th(struct gfs2_glock *gl);
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static DECLARE_RWSEM(gfs2_umount_flush_sem);
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static struct dentry *gfs2_root;
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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 gfs2_gl_hash_bucket gl_hash_table[GFS2_GL_HASH_SIZE];
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/*
 * Despite what you might think, the numbers below are not arbitrary :-)
 * They are taken from the ipv4 routing hash code, which is well tested
 * and thus should be nearly optimal. Later on we might tweek the numbers
 * but for now this should be fine.
 *
 * The reason for putting the locks in a separate array from the list heads
 * is that we can have fewer locks than list heads and save memory. We use
 * the same hash function for both, but with a different hash mask.
 */
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) || \
	defined(CONFIG_PROVE_LOCKING)

#ifdef CONFIG_LOCKDEP
# define GL_HASH_LOCK_SZ        256
#else
# if NR_CPUS >= 32
#  define GL_HASH_LOCK_SZ       4096
# elif NR_CPUS >= 16
#  define GL_HASH_LOCK_SZ       2048
# elif NR_CPUS >= 8
#  define GL_HASH_LOCK_SZ       1024
# elif NR_CPUS >= 4
#  define GL_HASH_LOCK_SZ       512
# else
#  define GL_HASH_LOCK_SZ       256
# endif
#endif

/* We never want more locks than chains */
#if GFS2_GL_HASH_SIZE < GL_HASH_LOCK_SZ
# undef GL_HASH_LOCK_SZ
# define GL_HASH_LOCK_SZ GFS2_GL_HASH_SIZE
#endif

static rwlock_t gl_hash_locks[GL_HASH_LOCK_SZ];

static inline rwlock_t *gl_lock_addr(unsigned int x)
{
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	return &gl_hash_locks[x & (GL_HASH_LOCK_SZ-1)];
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}
#else /* not SMP, so no spinlocks required */
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static inline rwlock_t *gl_lock_addr(unsigned int x)
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{
	return NULL;
}
#endif
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/**
 * relaxed_state_ok - is a requested lock compatible with the current lock mode?
 * @actual: the current state of the lock
 * @requested: the lock state that was requested by the caller
 * @flags: the modifier flags passed in by the caller
 *
 * Returns: 1 if the locks are compatible, 0 otherwise
 */

static inline int relaxed_state_ok(unsigned int actual, unsigned requested,
				   int flags)
{
	if (actual == requested)
		return 1;

	if (flags & GL_EXACT)
		return 0;

	if (actual == LM_ST_EXCLUSIVE && requested == LM_ST_SHARED)
		return 1;

	if (actual != LM_ST_UNLOCKED && (flags & LM_FLAG_ANY))
		return 1;

	return 0;
}

/**
 * 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;
}

/**
 * glock_free() - Perform a few checks and then release struct gfs2_glock
 * @gl: The glock to release
 *
 * Also calls lock module to release its internal structure for this glock.
 *
 */

static void glock_free(struct gfs2_glock *gl)
{
	struct gfs2_sbd *sdp = gl->gl_sbd;
	struct inode *aspace = gl->gl_aspace;

	gfs2_lm_put_lock(sdp, gl->gl_lock);

	if (aspace)
		gfs2_aspace_put(aspace);

	kmem_cache_free(gfs2_glock_cachep, gl);
}

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

void gfs2_glock_hold(struct gfs2_glock *gl)
{
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	atomic_inc(&gl->gl_ref);
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}

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

int gfs2_glock_put(struct gfs2_glock *gl)
{
	int rv = 0;
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	struct gfs2_sbd *sdp = gl->gl_sbd;
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	write_lock(gl_lock_addr(gl->gl_hash));
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	if (atomic_dec_and_test(&gl->gl_ref)) {
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		hlist_del(&gl->gl_list);
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		write_unlock(gl_lock_addr(gl->gl_hash));
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		BUG_ON(spin_is_locked(&gl->gl_spin));
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		gfs2_assert(sdp, gl->gl_state == LM_ST_UNLOCKED);
		gfs2_assert(sdp, list_empty(&gl->gl_reclaim));
		gfs2_assert(sdp, list_empty(&gl->gl_holders));
		gfs2_assert(sdp, list_empty(&gl->gl_waiters1));
		gfs2_assert(sdp, list_empty(&gl->gl_waiters3));
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		glock_free(gl);
		rv = 1;
		goto out;
	}
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	write_unlock(gl_lock_addr(gl->gl_hash));
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out:
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	return rv;
}

/**
 * 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_node *h;
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	hlist_for_each_entry(gl, h, &gl_hash_table[hash].hb_list, 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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		atomic_inc(&gl->gl_ref);
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		return gl;
	}

	return NULL;
}

/**
 * gfs2_glock_find() - Find glock by lock number
 * @sdp: The GFS2 superblock
 * @name: The lock name
 *
 * Returns: NULL, or the struct gfs2_glock with the requested number
 */

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static struct gfs2_glock *gfs2_glock_find(const struct gfs2_sbd *sdp,
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					  const struct lm_lockname *name)
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{
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	unsigned int hash = gl_hash(sdp, name);
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	struct gfs2_glock *gl;

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	read_lock(gl_lock_addr(hash));
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	gl = search_bucket(hash, sdp, name);
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	read_unlock(gl_lock_addr(hash));
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	return gl;
}

/**
 * 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
 */

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int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
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		   const struct gfs2_glock_operations *glops, int create,
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		   struct gfs2_glock **glp)
{
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	struct lm_lockname name = { .ln_number = number, .ln_type = glops->go_type };
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	struct gfs2_glock *gl, *tmp;
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	unsigned int hash = gl_hash(sdp, &name);
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	int error;

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	read_lock(gl_lock_addr(hash));
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	gl = search_bucket(hash, sdp, &name);
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	read_unlock(gl_lock_addr(hash));
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	if (gl || !create) {
		*glp = gl;
		return 0;
	}

	gl = kmem_cache_alloc(gfs2_glock_cachep, GFP_KERNEL);
	if (!gl)
		return -ENOMEM;

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	gl->gl_flags = 0;
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	gl->gl_name = name;
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	atomic_set(&gl->gl_ref, 1);
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	gl->gl_state = LM_ST_UNLOCKED;
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	gl->gl_hash = hash;
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	gl->gl_owner = NULL;
	gl->gl_ip = 0;
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	gl->gl_ops = glops;
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	gl->gl_req_gh = NULL;
	gl->gl_req_bh = NULL;
	gl->gl_vn = 0;
	gl->gl_stamp = jiffies;
	gl->gl_object = NULL;
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	gl->gl_sbd = sdp;
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	gl->gl_aspace = NULL;
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	lops_init_le(&gl->gl_le, &gfs2_glock_lops);

	/* If this glock protects actual on-disk data or metadata blocks,
	   create a VFS inode to manage the pages/buffers holding them. */
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	if (glops == &gfs2_inode_glops || glops == &gfs2_rgrp_glops) {
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		gl->gl_aspace = gfs2_aspace_get(sdp);
		if (!gl->gl_aspace) {
			error = -ENOMEM;
			goto fail;
		}
	}

	error = gfs2_lm_get_lock(sdp, &name, &gl->gl_lock);
	if (error)
		goto fail_aspace;

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	write_lock(gl_lock_addr(hash));
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	tmp = search_bucket(hash, sdp, &name);
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	if (tmp) {
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		write_unlock(gl_lock_addr(hash));
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		glock_free(gl);
		gl = tmp;
	} else {
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		hlist_add_head(&gl->gl_list, &gl_hash_table[hash].hb_list);
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		write_unlock(gl_lock_addr(hash));
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	}

	*glp = gl;

	return 0;

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fail_aspace:
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	if (gl->gl_aspace)
		gfs2_aspace_put(gl->gl_aspace);
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fail:
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	kmem_cache_free(gfs2_glock_cachep, gl);
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	return error;
}

/**
 * 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
 *
 */

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void gfs2_holder_init(struct gfs2_glock *gl, unsigned int state, unsigned flags,
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		      struct gfs2_holder *gh)
{
	INIT_LIST_HEAD(&gh->gh_list);
	gh->gh_gl = gl;
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	gh->gh_ip = (unsigned long)__builtin_return_address(0);
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	gh->gh_owner = current;
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	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.
 *
 */

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void gfs2_holder_reinit(unsigned int state, unsigned flags, struct gfs2_holder *gh)
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{
	gh->gh_state = state;
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	gh->gh_flags = flags;
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	gh->gh_iflags = 0;
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	gh->gh_ip = (unsigned long)__builtin_return_address(0);
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}

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

void gfs2_holder_uninit(struct gfs2_holder *gh)
{
	gfs2_glock_put(gh->gh_gl);
	gh->gh_gl = NULL;
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	gh->gh_ip = 0;
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}

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

static int holder_wait(void *word)
{
        schedule();
        return 0;
}

static void wait_on_holder(struct gfs2_holder *gh)
{
	might_sleep();
	wait_on_bit(&gh->gh_iflags, HIF_WAIT, holder_wait, TASK_UNINTERRUPTIBLE);
}

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/**
 * rq_mutex - process a mutex request in the queue
 * @gh: the glock holder
 *
 * Returns: 1 if the queue is blocked
 */

static int rq_mutex(struct gfs2_holder *gh)
{
	struct gfs2_glock *gl = gh->gh_gl;

	list_del_init(&gh->gh_list);
	/*  gh->gh_error never examined.  */
	set_bit(GLF_LOCK, &gl->gl_flags);
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	clear_bit(HIF_WAIT, &gh->gh_iflags);
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	smp_mb();
	wake_up_bit(&gh->gh_iflags, HIF_WAIT);
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	return 1;
}

/**
 * rq_promote - process a promote request in the queue
 * @gh: the glock holder
 *
 * Acquire a new inter-node lock, or change a lock state to more restrictive.
 *
 * Returns: 1 if the queue is blocked
 */

static int rq_promote(struct gfs2_holder *gh)
{
	struct gfs2_glock *gl = gh->gh_gl;
	struct gfs2_sbd *sdp = gl->gl_sbd;

	if (!relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
		if (list_empty(&gl->gl_holders)) {
			gl->gl_req_gh = gh;
			set_bit(GLF_LOCK, &gl->gl_flags);
			spin_unlock(&gl->gl_spin);

			if (atomic_read(&sdp->sd_reclaim_count) >
			    gfs2_tune_get(sdp, gt_reclaim_limit) &&
			    !(gh->gh_flags & LM_FLAG_PRIORITY)) {
				gfs2_reclaim_glock(sdp);
				gfs2_reclaim_glock(sdp);
			}

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			gfs2_glock_xmote_th(gh->gh_gl, gh);
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			spin_lock(&gl->gl_spin);
		}
		return 1;
	}

	if (list_empty(&gl->gl_holders)) {
		set_bit(HIF_FIRST, &gh->gh_iflags);
		set_bit(GLF_LOCK, &gl->gl_flags);
	} else {
		struct gfs2_holder *next_gh;
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		if (gh->gh_state == LM_ST_EXCLUSIVE)
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			return 1;
		next_gh = list_entry(gl->gl_holders.next, struct gfs2_holder,
				     gh_list);
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		if (next_gh->gh_state == LM_ST_EXCLUSIVE)
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			 return 1;
	}

	list_move_tail(&gh->gh_list, &gl->gl_holders);
	gh->gh_error = 0;
	set_bit(HIF_HOLDER, &gh->gh_iflags);

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	gfs2_holder_wake(gh);
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	return 0;
}

/**
 * rq_demote - process a demote request in the queue
 * @gh: the glock holder
 *
 * Returns: 1 if the queue is blocked
 */

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static int rq_demote(struct gfs2_glock *gl)
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{
	if (!list_empty(&gl->gl_holders))
		return 1;

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	if (gl->gl_state == gl->gl_demote_state ||
	    gl->gl_state == LM_ST_UNLOCKED) {
		clear_bit(GLF_DEMOTE, &gl->gl_flags);
		return 0;
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	}
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	set_bit(GLF_LOCK, &gl->gl_flags);
	spin_unlock(&gl->gl_spin);
	if (gl->gl_demote_state == LM_ST_UNLOCKED ||
	    gl->gl_state != LM_ST_EXCLUSIVE)
		gfs2_glock_drop_th(gl);
	else
		gfs2_glock_xmote_th(gl, NULL);
	spin_lock(&gl->gl_spin);
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	return 0;
}

/**
 * run_queue - process holder structures on a glock
 * @gl: the glock
 *
 */
static void run_queue(struct gfs2_glock *gl)
{
	struct gfs2_holder *gh;
	int blocked = 1;

	for (;;) {
		if (test_bit(GLF_LOCK, &gl->gl_flags))
			break;

		if (!list_empty(&gl->gl_waiters1)) {
			gh = list_entry(gl->gl_waiters1.next,
					struct gfs2_holder, gh_list);

			if (test_bit(HIF_MUTEX, &gh->gh_iflags))
				blocked = rq_mutex(gh);
			else
				gfs2_assert_warn(gl->gl_sbd, 0);

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		} else if (test_bit(GLF_DEMOTE, &gl->gl_flags)) {
			blocked = rq_demote(gl);
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		} else if (!list_empty(&gl->gl_waiters3)) {
			gh = list_entry(gl->gl_waiters3.next,
					struct gfs2_holder, gh_list);

			if (test_bit(HIF_PROMOTE, &gh->gh_iflags))
				blocked = rq_promote(gh);
			else
				gfs2_assert_warn(gl->gl_sbd, 0);

		} else
			break;

		if (blocked)
			break;
	}
}

/**
 * gfs2_glmutex_lock - acquire a local lock on a glock
 * @gl: the glock
 *
 * Gives caller exclusive access to manipulate a glock structure.
 */

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static void gfs2_glmutex_lock(struct gfs2_glock *gl)
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{
	struct gfs2_holder gh;

	gfs2_holder_init(gl, 0, 0, &gh);
	set_bit(HIF_MUTEX, &gh.gh_iflags);
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	if (test_and_set_bit(HIF_WAIT, &gh.gh_iflags))
		BUG();
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	spin_lock(&gl->gl_spin);
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	if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
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		list_add_tail(&gh.gh_list, &gl->gl_waiters1);
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	} else {
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		gl->gl_owner = current;
		gl->gl_ip = (unsigned long)__builtin_return_address(0);
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		clear_bit(HIF_WAIT, &gh.gh_iflags);
		smp_mb();
		wake_up_bit(&gh.gh_iflags, HIF_WAIT);
609
	}
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610 611
	spin_unlock(&gl->gl_spin);

612
	wait_on_holder(&gh);
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613 614 615 616 617 618 619 620 621 622
	gfs2_holder_uninit(&gh);
}

/**
 * gfs2_glmutex_trylock - try to acquire a local lock on a glock
 * @gl: the glock
 *
 * Returns: 1 if the glock is acquired
 */

623
static int gfs2_glmutex_trylock(struct gfs2_glock *gl)
D
David Teigland 已提交
624 625 626 627
{
	int acquired = 1;

	spin_lock(&gl->gl_spin);
628
	if (test_and_set_bit(GLF_LOCK, &gl->gl_flags)) {
D
David Teigland 已提交
629
		acquired = 0;
630
	} else {
631 632 633
		gl->gl_owner = current;
		gl->gl_ip = (unsigned long)__builtin_return_address(0);
	}
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634 635 636 637 638 639 640 641 642 643 644
	spin_unlock(&gl->gl_spin);

	return acquired;
}

/**
 * gfs2_glmutex_unlock - release a local lock on a glock
 * @gl: the glock
 *
 */

645
static void gfs2_glmutex_unlock(struct gfs2_glock *gl)
D
David Teigland 已提交
646 647 648
{
	spin_lock(&gl->gl_spin);
	clear_bit(GLF_LOCK, &gl->gl_flags);
649 650
	gl->gl_owner = NULL;
	gl->gl_ip = 0;
D
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651
	run_queue(gl);
652
	BUG_ON(!spin_is_locked(&gl->gl_spin));
D
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653 654 655 656
	spin_unlock(&gl->gl_spin);
}

/**
657
 * handle_callback - process a demote request
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 * @gl: the glock
 * @state: the state the caller wants us to change to
 *
661 662
 * There are only two requests that we are going to see in actual
 * practise: LM_ST_SHARED and LM_ST_UNLOCKED
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 */

static void handle_callback(struct gfs2_glock *gl, unsigned int state)
{
	spin_lock(&gl->gl_spin);
668 669 670 671 672
	if (test_and_set_bit(GLF_DEMOTE, &gl->gl_flags) == 0) {
		gl->gl_demote_state = state;
		gl->gl_demote_time = jiffies;
	} else if (gl->gl_demote_state != LM_ST_UNLOCKED) {
		gl->gl_demote_state = state;
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	}
	spin_unlock(&gl->gl_spin);
}

/**
 * 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) {
692
		if (held2)
D
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			gfs2_glock_hold(gl);
694
		else
D
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			gfs2_glock_put(gl);
	}

	gl->gl_state = new_state;
}

/**
 * xmote_bh - Called after the lock module is done acquiring a lock
 * @gl: The glock in question
 * @ret: the int returned from the lock module
 *
 */

static void xmote_bh(struct gfs2_glock *gl, unsigned int ret)
{
	struct gfs2_sbd *sdp = gl->gl_sbd;
711
	const struct gfs2_glock_operations *glops = gl->gl_ops;
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	struct gfs2_holder *gh = gl->gl_req_gh;
	int prev_state = gl->gl_state;
	int op_done = 1;

	gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
717
	gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
D
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	gfs2_assert_warn(sdp, !(ret & LM_OUT_ASYNC));

	state_change(gl, ret & LM_OUT_ST_MASK);

	if (prev_state != LM_ST_UNLOCKED && !(ret & LM_OUT_CACHEABLE)) {
		if (glops->go_inval)
724
			glops->go_inval(gl, DIO_METADATA);
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	} else if (gl->gl_state == LM_ST_DEFERRED) {
		/* We might not want to do this here.
		   Look at moving to the inode glops. */
		if (glops->go_inval)
729
			glops->go_inval(gl, 0);
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730 731 732 733
	}

	/*  Deal with each possible exit condition  */

734
	if (!gh) {
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		gl->gl_stamp = jiffies;
736 737 738 739 740
		if (ret & LM_OUT_CANCELED)
			op_done = 0;
		else
			clear_bit(GLF_DEMOTE, &gl->gl_flags);
	} else {
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		spin_lock(&gl->gl_spin);
		list_del_init(&gh->gh_list);
		gh->gh_error = -EIO;
744 745 746 747 748 749 750
		if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) 
			goto out;
		gh->gh_error = GLR_CANCELED;
		if (ret & LM_OUT_CANCELED) 
			goto out;
		if (relaxed_state_ok(gl->gl_state, gh->gh_state, gh->gh_flags)) {
			list_add_tail(&gh->gh_list, &gl->gl_holders);
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			gh->gh_error = 0;
752 753 754 755
			set_bit(HIF_HOLDER, &gh->gh_iflags);
			set_bit(HIF_FIRST, &gh->gh_iflags);
			op_done = 0;
			goto out;
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		}
		gh->gh_error = GLR_TRYFAILED;
758 759 760
		if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB))
			goto out;
		gh->gh_error = -EINVAL;
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		if (gfs2_assert_withdraw(sdp, 0) == -1)
			fs_err(sdp, "ret = 0x%.8X\n", ret);
763 764
out:
		spin_unlock(&gl->gl_spin);
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	}

	if (glops->go_xmote_bh)
		glops->go_xmote_bh(gl);

	if (op_done) {
		spin_lock(&gl->gl_spin);
		gl->gl_req_gh = NULL;
		gl->gl_req_bh = NULL;
		clear_bit(GLF_LOCK, &gl->gl_flags);
		run_queue(gl);
		spin_unlock(&gl->gl_spin);
	}

	gfs2_glock_put(gl);

781
	if (gh)
782
		gfs2_holder_wake(gh);
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}

/**
 * gfs2_glock_xmote_th - Call into the lock module to acquire or change a glock
 * @gl: The glock in question
 * @state: the requested state
 * @flags: modifier flags to the lock call
 *
 */

793
void gfs2_glock_xmote_th(struct gfs2_glock *gl, struct gfs2_holder *gh)
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{
	struct gfs2_sbd *sdp = gl->gl_sbd;
796 797
	int flags = gh ? gh->gh_flags : 0;
	unsigned state = gh ? gh->gh_state : gl->gl_demote_state;
798
	const struct gfs2_glock_operations *glops = gl->gl_ops;
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	int lck_flags = flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB |
				 LM_FLAG_NOEXP | LM_FLAG_ANY |
				 LM_FLAG_PRIORITY);
	unsigned int lck_ret;

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	if (glops->go_xmote_th)
		glops->go_xmote_th(gl);

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807
	gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
808
	gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
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809 810 811 812 813 814
	gfs2_assert_warn(sdp, state != LM_ST_UNLOCKED);
	gfs2_assert_warn(sdp, state != gl->gl_state);

	gfs2_glock_hold(gl);
	gl->gl_req_bh = xmote_bh;

815
	lck_ret = gfs2_lm_lock(sdp, gl->gl_lock, gl->gl_state, state, lck_flags);
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816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838

	if (gfs2_assert_withdraw(sdp, !(lck_ret & LM_OUT_ERROR)))
		return;

	if (lck_ret & LM_OUT_ASYNC)
		gfs2_assert_warn(sdp, lck_ret == LM_OUT_ASYNC);
	else
		xmote_bh(gl, lck_ret);
}

/**
 * drop_bh - Called after a lock module unlock completes
 * @gl: the glock
 * @ret: the return status
 *
 * Doesn't wake up the process waiting on the struct gfs2_holder (if any)
 * Doesn't drop the reference on the glock the top half took out
 *
 */

static void drop_bh(struct gfs2_glock *gl, unsigned int ret)
{
	struct gfs2_sbd *sdp = gl->gl_sbd;
839
	const struct gfs2_glock_operations *glops = gl->gl_ops;
D
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	struct gfs2_holder *gh = gl->gl_req_gh;

	gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
843
	gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
D
David Teigland 已提交
844 845 846
	gfs2_assert_warn(sdp, !ret);

	state_change(gl, LM_ST_UNLOCKED);
847
	clear_bit(GLF_DEMOTE, &gl->gl_flags);
D
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848 849

	if (glops->go_inval)
850
		glops->go_inval(gl, DIO_METADATA);
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851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867

	if (gh) {
		spin_lock(&gl->gl_spin);
		list_del_init(&gh->gh_list);
		gh->gh_error = 0;
		spin_unlock(&gl->gl_spin);
	}

	spin_lock(&gl->gl_spin);
	gl->gl_req_gh = NULL;
	gl->gl_req_bh = NULL;
	clear_bit(GLF_LOCK, &gl->gl_flags);
	run_queue(gl);
	spin_unlock(&gl->gl_spin);

	gfs2_glock_put(gl);

868
	if (gh)
869
		gfs2_holder_wake(gh);
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870 871 872 873 874 875 876 877
}

/**
 * gfs2_glock_drop_th - call into the lock module to unlock a lock
 * @gl: the glock
 *
 */

S
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878
static void gfs2_glock_drop_th(struct gfs2_glock *gl)
D
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879 880
{
	struct gfs2_sbd *sdp = gl->gl_sbd;
881
	const struct gfs2_glock_operations *glops = gl->gl_ops;
D
David Teigland 已提交
882 883
	unsigned int ret;

S
Steven Whitehouse 已提交
884 885 886
	if (glops->go_drop_th)
		glops->go_drop_th(gl);

D
David Teigland 已提交
887
	gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));
888
	gfs2_assert_warn(sdp, list_empty(&gl->gl_holders));
D
David Teigland 已提交
889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920
	gfs2_assert_warn(sdp, gl->gl_state != LM_ST_UNLOCKED);

	gfs2_glock_hold(gl);
	gl->gl_req_bh = drop_bh;

	ret = gfs2_lm_unlock(sdp, gl->gl_lock, gl->gl_state);

	if (gfs2_assert_withdraw(sdp, !(ret & LM_OUT_ERROR)))
		return;

	if (!ret)
		drop_bh(gl, ret);
	else
		gfs2_assert_warn(sdp, ret == LM_OUT_ASYNC);
}

/**
 * do_cancels - cancel requests for locks stuck waiting on an expire flag
 * @gh: the LM_FLAG_PRIORITY holder waiting to acquire the lock
 *
 * Don't cancel GL_NOCANCEL requests.
 */

static void do_cancels(struct gfs2_holder *gh)
{
	struct gfs2_glock *gl = gh->gh_gl;

	spin_lock(&gl->gl_spin);

	while (gl->gl_req_gh != gh &&
	       !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
	       !list_empty(&gh->gh_list)) {
S
Steven Whitehouse 已提交
921 922
		if (gl->gl_req_bh && !(gl->gl_req_gh &&
				     (gl->gl_req_gh->gh_flags & GL_NOCANCEL))) {
D
David Teigland 已提交
923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947
			spin_unlock(&gl->gl_spin);
			gfs2_lm_cancel(gl->gl_sbd, gl->gl_lock);
			msleep(100);
			spin_lock(&gl->gl_spin);
		} else {
			spin_unlock(&gl->gl_spin);
			msleep(100);
			spin_lock(&gl->gl_spin);
		}
	}

	spin_unlock(&gl->gl_spin);
}

/**
 * glock_wait_internal - wait on a glock acquisition
 * @gh: the glock holder
 *
 * Returns: 0 on success
 */

static int glock_wait_internal(struct gfs2_holder *gh)
{
	struct gfs2_glock *gl = gh->gh_gl;
	struct gfs2_sbd *sdp = gl->gl_sbd;
948
	const struct gfs2_glock_operations *glops = gl->gl_ops;
D
David Teigland 已提交
949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969

	if (test_bit(HIF_ABORTED, &gh->gh_iflags))
		return -EIO;

	if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) {
		spin_lock(&gl->gl_spin);
		if (gl->gl_req_gh != gh &&
		    !test_bit(HIF_HOLDER, &gh->gh_iflags) &&
		    !list_empty(&gh->gh_list)) {
			list_del_init(&gh->gh_list);
			gh->gh_error = GLR_TRYFAILED;
			run_queue(gl);
			spin_unlock(&gl->gl_spin);
			return gh->gh_error;
		}
		spin_unlock(&gl->gl_spin);
	}

	if (gh->gh_flags & LM_FLAG_PRIORITY)
		do_cancels(gh);

970
	wait_on_holder(gh);
D
David Teigland 已提交
971 972 973 974
	if (gh->gh_error)
		return gh->gh_error;

	gfs2_assert_withdraw(sdp, test_bit(HIF_HOLDER, &gh->gh_iflags));
975
	gfs2_assert_withdraw(sdp, relaxed_state_ok(gl->gl_state, gh->gh_state,
D
David Teigland 已提交
976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013
						   gh->gh_flags));

	if (test_bit(HIF_FIRST, &gh->gh_iflags)) {
		gfs2_assert_warn(sdp, test_bit(GLF_LOCK, &gl->gl_flags));

		if (glops->go_lock) {
			gh->gh_error = glops->go_lock(gh);
			if (gh->gh_error) {
				spin_lock(&gl->gl_spin);
				list_del_init(&gh->gh_list);
				spin_unlock(&gl->gl_spin);
			}
		}

		spin_lock(&gl->gl_spin);
		gl->gl_req_gh = NULL;
		gl->gl_req_bh = NULL;
		clear_bit(GLF_LOCK, &gl->gl_flags);
		run_queue(gl);
		spin_unlock(&gl->gl_spin);
	}

	return gh->gh_error;
}

static inline struct gfs2_holder *
find_holder_by_owner(struct list_head *head, struct task_struct *owner)
{
	struct gfs2_holder *gh;

	list_for_each_entry(gh, head, gh_list) {
		if (gh->gh_owner == owner)
			return gh;
	}

	return NULL;
}

1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027
static void print_dbg(struct glock_iter *gi, const char *fmt, ...)
{
	va_list args;

	va_start(args, fmt);
	if (gi) {
		vsprintf(gi->string, fmt, args);
		seq_printf(gi->seq, gi->string);
	}
	else
		vprintk(fmt, args);
	va_end(args);
}

D
David Teigland 已提交
1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038
/**
 * add_to_queue - Add a holder to the wait queue (but look for recursion)
 * @gh: the holder structure to add
 *
 */

static void add_to_queue(struct gfs2_holder *gh)
{
	struct gfs2_glock *gl = gh->gh_gl;
	struct gfs2_holder *existing;

1039
	BUG_ON(!gh->gh_owner);
1040 1041
	if (test_and_set_bit(HIF_WAIT, &gh->gh_iflags))
		BUG();
1042

D
David Teigland 已提交
1043 1044
	existing = find_holder_by_owner(&gl->gl_holders, gh->gh_owner);
	if (existing) {
1045
		print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
1046
		printk(KERN_INFO "pid : %d\n", existing->gh_owner->pid);
1047
		printk(KERN_INFO "lock type : %d lock state : %d\n",
1048
				existing->gh_gl->gl_name.ln_type, existing->gh_gl->gl_state);
1049
		print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
1050
		printk(KERN_INFO "pid : %d\n", gh->gh_owner->pid);
1051
		printk(KERN_INFO "lock type : %d lock state : %d\n",
1052
				gl->gl_name.ln_type, gl->gl_state);
1053
		BUG();
D
David Teigland 已提交
1054 1055 1056 1057
	}

	existing = find_holder_by_owner(&gl->gl_waiters3, gh->gh_owner);
	if (existing) {
1058 1059 1060
		print_symbol(KERN_WARNING "original: %s\n", existing->gh_ip);
		print_symbol(KERN_WARNING "new: %s\n", gh->gh_ip);
		BUG();
D
David Teigland 已提交
1061 1062 1063 1064 1065
	}

	if (gh->gh_flags & LM_FLAG_PRIORITY)
		list_add(&gh->gh_list, &gl->gl_waiters3);
	else
1066
		list_add_tail(&gh->gh_list, &gl->gl_waiters3);
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David Teigland 已提交
1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083
}

/**
 * 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;

1084
restart:
D
David Teigland 已提交
1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099
	if (unlikely(test_bit(SDF_SHUTDOWN, &sdp->sd_flags))) {
		set_bit(HIF_ABORTED, &gh->gh_iflags);
		return -EIO;
	}

	set_bit(HIF_PROMOTE, &gh->gh_iflags);

	spin_lock(&gl->gl_spin);
	add_to_queue(gh);
	run_queue(gl);
	spin_unlock(&gl->gl_spin);

	if (!(gh->gh_flags & GL_ASYNC)) {
		error = glock_wait_internal(gh);
		if (error == GLR_CANCELED) {
1100
			msleep(100);
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David Teigland 已提交
1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126
			goto restart;
		}
	}

	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)
{
	struct gfs2_glock *gl = gh->gh_gl;
	int ready = 0;

	spin_lock(&gl->gl_spin);

	if (test_bit(HIF_HOLDER, &gh->gh_iflags))
		ready = 1;
	else if (list_empty(&gh->gh_list)) {
		if (gh->gh_error == GLR_CANCELED) {
			spin_unlock(&gl->gl_spin);
1127
			msleep(100);
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David Teigland 已提交
1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152
			if (gfs2_glock_nq(gh))
				return 1;
			return 0;
		} else
			ready = 1;
	}

	spin_unlock(&gl->gl_spin);

	return ready;
}

/**
 * gfs2_glock_wait - wait for a lock acquisition that ended in a GLR_ASYNC
 * @gh: the holder structure
 *
 * Returns: 0, GLR_TRYFAILED, or errno on failure
 */

int gfs2_glock_wait(struct gfs2_holder *gh)
{
	int error;

	error = glock_wait_internal(gh);
	if (error == GLR_CANCELED) {
1153
		msleep(100);
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1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169
		gh->gh_flags &= ~GL_ASYNC;
		error = gfs2_glock_nq(gh);
	}

	return error;
}

/**
 * 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;
1170
	const struct gfs2_glock_operations *glops = gl->gl_ops;
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	if (gh->gh_flags & GL_NOCACHE)
		handle_callback(gl, LM_ST_UNLOCKED);

	gfs2_glmutex_lock(gl);

	spin_lock(&gl->gl_spin);
	list_del_init(&gh->gh_list);

	if (list_empty(&gl->gl_holders)) {
		spin_unlock(&gl->gl_spin);

		if (glops->go_unlock)
			glops->go_unlock(gh);

		spin_lock(&gl->gl_spin);
1187
		gl->gl_stamp = jiffies;
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	}

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

/**
 * 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
 * @flags: modifier flags for the aquisition
 * @gh: the struct gfs2_holder
 *
 * Returns: errno
 */

1219
int gfs2_glock_nq_num(struct gfs2_sbd *sdp, u64 number,
1220 1221
		      const struct gfs2_glock_operations *glops,
		      unsigned int state, int flags, struct gfs2_holder *gh)
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{
	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)
{
1244 1245 1246 1247
	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;
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	if (a->ln_number > b->ln_number)
1250 1251 1252
		return 1;
	if (a->ln_number < b->ln_number)
		return -1;
1253
	BUG_ON(gh_a->gh_gl->gl_ops->go_type == gh_b->gh_gl->gl_ops->go_type);
1254
	return 0;
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}

/**
 * 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
 *
 * Figure out how big an impact this function has.  Either:
 * 1) Replace this code with code that calls gfs2_glock_prefetch()
 * 2) Forget async stuff and just call nq_m_sync()
 * 3) Leave it like it is
 *
 * 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)
{
	int *e;
	unsigned int x;
	int borked = 0, serious = 0;
	int error = 0;

	if (!num_gh)
		return 0;

	if (num_gh == 1) {
		ghs->gh_flags &= ~(LM_FLAG_TRY | GL_ASYNC);
		return gfs2_glock_nq(ghs);
	}

	e = kcalloc(num_gh, sizeof(struct gfs2_holder *), GFP_KERNEL);
	if (!e)
		return -ENOMEM;

	for (x = 0; x < num_gh; x++) {
		ghs[x].gh_flags |= LM_FLAG_TRY | GL_ASYNC;
		error = gfs2_glock_nq(&ghs[x]);
		if (error) {
			borked = 1;
			serious = error;
			num_gh = x;
			break;
		}
	}

	for (x = 0; x < num_gh; x++) {
		error = e[x] = glock_wait_internal(&ghs[x]);
		if (error) {
			borked = 1;
			if (error != GLR_TRYFAILED && error != GLR_CANCELED)
				serious = error;
		}
	}

	if (!borked) {
		kfree(e);
		return 0;
	}

	for (x = 0; x < num_gh; x++)
		if (!e[x])
			gfs2_glock_dq(&ghs[x]);

	if (serious)
		error = serious;
	else {
		for (x = 0; x < num_gh; x++)
			gfs2_holder_reinit(ghs[x].gh_state, ghs[x].gh_flags,
					  &ghs[x]);
		error = nq_m_sync(num_gh, ghs, (struct gfs2_holder **)e);
	}

	kfree(e);

	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)
{
	unsigned int x;

	for (x = 0; x < num_gh; x++)
		gfs2_glock_dq(&ghs[x]);
}

/**
 * gfs2_glock_dq_uninit_m - release multiple glocks
 * @num_gh: the number of structures
 * @ghs: an array of struct gfs2_holder structures
 *
 */

void gfs2_glock_dq_uninit_m(unsigned int num_gh, struct gfs2_holder *ghs)
{
	unsigned int x;

	for (x = 0; x < num_gh; x++)
		gfs2_glock_dq_uninit(&ghs[x]);
}

/**
 * gfs2_lvb_hold - attach a LVB from a glock
 * @gl: The glock in question
 *
 */

int gfs2_lvb_hold(struct gfs2_glock *gl)
{
	int error;

	gfs2_glmutex_lock(gl);

	if (!atomic_read(&gl->gl_lvb_count)) {
		error = gfs2_lm_hold_lvb(gl->gl_sbd, gl->gl_lock, &gl->gl_lvb);
		if (error) {
			gfs2_glmutex_unlock(gl);
			return error;
		}
		gfs2_glock_hold(gl);
	}
	atomic_inc(&gl->gl_lvb_count);

	gfs2_glmutex_unlock(gl);

	return 0;
}

/**
 * gfs2_lvb_unhold - detach a LVB from a glock
 * @gl: The glock in question
 *
 */

void gfs2_lvb_unhold(struct gfs2_glock *gl)
{
	gfs2_glock_hold(gl);
	gfs2_glmutex_lock(gl);

	gfs2_assert(gl->gl_sbd, atomic_read(&gl->gl_lvb_count) > 0);
	if (atomic_dec_and_test(&gl->gl_lvb_count)) {
		gfs2_lm_unhold_lvb(gl->gl_sbd, gl->gl_lock, gl->gl_lvb);
		gl->gl_lvb = NULL;
		gfs2_glock_put(gl);
	}

	gfs2_glmutex_unlock(gl);
	gfs2_glock_put(gl);
}

static void blocking_cb(struct gfs2_sbd *sdp, struct lm_lockname *name,
			unsigned int state)
{
	struct gfs2_glock *gl;

	gl = gfs2_glock_find(sdp, name);
	if (!gl)
		return;

	handle_callback(gl, state);

	spin_lock(&gl->gl_spin);
	run_queue(gl);
	spin_unlock(&gl->gl_spin);

	gfs2_glock_put(gl);
}

/**
 * gfs2_glock_cb - Callback used by locking module
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 * @sdp: Pointer to the superblock
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 * @type: Type of callback
 * @data: Type dependent data pointer
 *
 * Called by the locking module when it wants to tell us something.
 * Either we need to drop a lock, one of our ASYNC requests completed, or
 * a journal from another client needs to be recovered.
 */

1475
void gfs2_glock_cb(void *cb_data, unsigned int type, void *data)
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{
1477
	struct gfs2_sbd *sdp = cb_data;
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	switch (type) {
	case LM_CB_NEED_E:
1481
		blocking_cb(sdp, data, LM_ST_UNLOCKED);
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		return;

	case LM_CB_NEED_D:
1485
		blocking_cb(sdp, data, LM_ST_DEFERRED);
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		return;

	case LM_CB_NEED_S:
1489
		blocking_cb(sdp, data, LM_ST_SHARED);
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		return;

	case LM_CB_ASYNC: {
1493
		struct lm_async_cb *async = data;
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		struct gfs2_glock *gl;

1496
		down_read(&gfs2_umount_flush_sem);
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		gl = gfs2_glock_find(sdp, &async->lc_name);
		if (gfs2_assert_warn(sdp, gl))
			return;
		if (!gfs2_assert_warn(sdp, gl->gl_req_bh))
			gl->gl_req_bh(gl, async->lc_ret);
		gfs2_glock_put(gl);
1503
		up_read(&gfs2_umount_flush_sem);
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		return;
	}

	case LM_CB_NEED_RECOVERY:
		gfs2_jdesc_make_dirty(sdp, *(unsigned int *)data);
		if (sdp->sd_recoverd_process)
			wake_up_process(sdp->sd_recoverd_process);
		return;

	case LM_CB_DROPLOCKS:
		gfs2_gl_hash_clear(sdp, NO_WAIT);
		gfs2_quota_scan(sdp);
		return;

	default:
		gfs2_assert_warn(sdp, 0);
		return;
	}
}

/**
 * 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(struct gfs2_glock *gl)
{
1533
	const struct gfs2_glock_operations *glops = gl->gl_ops;
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	int demote = 1;

	if (test_bit(GLF_STICKY, &gl->gl_flags))
		demote = 0;
	else if (glops->go_demote_ok)
		demote = glops->go_demote_ok(gl);

	return demote;
}

/**
 * gfs2_glock_schedule_for_reclaim - Add a glock to the reclaim list
 * @gl: the glock
 *
 */

void gfs2_glock_schedule_for_reclaim(struct gfs2_glock *gl)
{
	struct gfs2_sbd *sdp = gl->gl_sbd;

	spin_lock(&sdp->sd_reclaim_lock);
	if (list_empty(&gl->gl_reclaim)) {
		gfs2_glock_hold(gl);
		list_add(&gl->gl_reclaim, &sdp->sd_reclaim_list);
		atomic_inc(&sdp->sd_reclaim_count);
	}
	spin_unlock(&sdp->sd_reclaim_lock);

	wake_up(&sdp->sd_reclaim_wq);
}

/**
 * gfs2_reclaim_glock - process the next glock on the filesystem's reclaim list
 * @sdp: the filesystem
 *
 * Called from gfs2_glockd() glock reclaim daemon, or when promoting a
 * different glock and we notice that there are a lot of glocks in the
 * reclaim list.
 *
 */

void gfs2_reclaim_glock(struct gfs2_sbd *sdp)
{
	struct gfs2_glock *gl;

	spin_lock(&sdp->sd_reclaim_lock);
	if (list_empty(&sdp->sd_reclaim_list)) {
		spin_unlock(&sdp->sd_reclaim_lock);
		return;
	}
	gl = list_entry(sdp->sd_reclaim_list.next,
			struct gfs2_glock, gl_reclaim);
	list_del_init(&gl->gl_reclaim);
	spin_unlock(&sdp->sd_reclaim_lock);

	atomic_dec(&sdp->sd_reclaim_count);
	atomic_inc(&sdp->sd_reclaimed);

	if (gfs2_glmutex_trylock(gl)) {
1593
		if (list_empty(&gl->gl_holders) &&
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		    gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl))
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			handle_callback(gl, LM_ST_UNLOCKED);
		gfs2_glmutex_unlock(gl);
	}

	gfs2_glock_put(gl);
}

/**
 * examine_bucket - Call a function for glock in a hash bucket
 * @examiner: the function
 * @sdp: the filesystem
 * @bucket: the bucket
 *
 * Returns: 1 if the bucket has entries
 */

static int examine_bucket(glock_examiner examiner, struct gfs2_sbd *sdp,
1612
			  unsigned int hash)
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{
1614 1615
	struct gfs2_glock *gl, *prev = NULL;
	int has_entries = 0;
1616
	struct hlist_head *head = &gl_hash_table[hash].hb_list;
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1618
	read_lock(gl_lock_addr(hash));
1619 1620
	/* Can't use hlist_for_each_entry - don't want prefetch here */
	if (hlist_empty(head))
1621
		goto out;
1622 1623
	gl = list_entry(head->first, struct gfs2_glock, gl_list);
	while(1) {
1624
		if (gl->gl_sbd == sdp) {
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			gfs2_glock_hold(gl);
1626 1627 1628 1629 1630
			read_unlock(gl_lock_addr(hash));
			if (prev)
				gfs2_glock_put(prev);
			prev = gl;
			examiner(gl);
1631
			has_entries = 1;
1632
			read_lock(gl_lock_addr(hash));
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		}
1634 1635
		if (gl->gl_list.next == NULL)
			break;
1636
		gl = list_entry(gl->gl_list.next, struct gfs2_glock, gl_list);
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	}
1638 1639 1640 1641 1642
out:
	read_unlock(gl_lock_addr(hash));
	if (prev)
		gfs2_glock_put(prev);
	return has_entries;
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}

/**
 * scan_glock - look at a glock and see if we can reclaim it
 * @gl: the glock to look at
 *
 */

static void scan_glock(struct gfs2_glock *gl)
{
1653
	if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object)
1654
		return;
1655

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	if (gfs2_glmutex_trylock(gl)) {
1657
		if (list_empty(&gl->gl_holders) &&
1658
		    gl->gl_state != LM_ST_UNLOCKED && demote_ok(gl))
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			goto out_schedule;
		gfs2_glmutex_unlock(gl);
	}
	return;

1664
out_schedule:
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	gfs2_glmutex_unlock(gl);
	gfs2_glock_schedule_for_reclaim(gl);
}

/**
 * gfs2_scand_internal - Look for glocks and inodes to toss from memory
 * @sdp: the filesystem
 *
 */

void gfs2_scand_internal(struct gfs2_sbd *sdp)
{
	unsigned int x;

1679
	for (x = 0; x < GFS2_GL_HASH_SIZE; x++)
1680
		examine_bucket(scan_glock, sdp, x);
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}

/**
 * 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)
{
	struct gfs2_sbd *sdp = gl->gl_sbd;
	int released;

	spin_lock(&sdp->sd_reclaim_lock);
	if (!list_empty(&gl->gl_reclaim)) {
		list_del_init(&gl->gl_reclaim);
		atomic_dec(&sdp->sd_reclaim_count);
1698
		spin_unlock(&sdp->sd_reclaim_lock);
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		released = gfs2_glock_put(gl);
		gfs2_assert(sdp, !released);
1701 1702
	} else {
		spin_unlock(&sdp->sd_reclaim_lock);
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	}

	if (gfs2_glmutex_trylock(gl)) {
1706
		if (list_empty(&gl->gl_holders) &&
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		    gl->gl_state != LM_ST_UNLOCKED)
			handle_callback(gl, LM_ST_UNLOCKED);
		gfs2_glmutex_unlock(gl);
	}
}

/**
 * gfs2_gl_hash_clear - Empty out the glock hash table
 * @sdp: the filesystem
 * @wait: wait until it's all gone
 *
 * Called when unmounting the filesystem, or when inter-node lock manager
 * requests DROPLOCKS because it is running out of capacity.
 */

void gfs2_gl_hash_clear(struct gfs2_sbd *sdp, int wait)
{
	unsigned long t;
	unsigned int x;
	int cont;

	t = jiffies;

	for (;;) {
		cont = 0;
1732
		for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {
1733
			if (examine_bucket(clear_glock, sdp, x))
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				cont = 1;
1735
		}
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		if (!wait || !cont)
			break;

		if (time_after_eq(jiffies,
				  t + gfs2_tune_get(sdp, gt_stall_secs) * HZ)) {
			fs_warn(sdp, "Unmount seems to be stalled. "
				     "Dumping lock state...\n");
			gfs2_dump_lockstate(sdp);
			t = jiffies;
		}

1748
		down_write(&gfs2_umount_flush_sem);
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1749
		invalidate_inodes(sdp->sd_vfs);
1750
		up_write(&gfs2_umount_flush_sem);
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1751
		msleep(10);
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	}
}

/*
 *  Diagnostic routines to help debug distributed deadlock
 */

/**
 * dump_holder - print information about a glock holder
 * @str: a string naming the type of holder
 * @gh: the glock holder
 *
 * Returns: 0 on success, -ENOBUFS when we run out of space
 */

1767 1768
static int dump_holder(struct glock_iter *gi, char *str,
		       struct gfs2_holder *gh)
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{
	unsigned int x;

1772 1773
	print_dbg(gi, "  %s\n", str);
	print_dbg(gi, "    owner = %ld\n",
D
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		   (gh->gh_owner) ? (long)gh->gh_owner->pid : -1);
1775 1776
	print_dbg(gi, "    gh_state = %u\n", gh->gh_state);
	print_dbg(gi, "    gh_flags =");
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1777 1778
	for (x = 0; x < 32; x++)
		if (gh->gh_flags & (1 << x))
1779 1780 1781 1782
			print_dbg(gi, " %u", x);
	print_dbg(gi, " \n");
	print_dbg(gi, "    error = %d\n", gh->gh_error);
	print_dbg(gi, "    gh_iflags =");
D
David Teigland 已提交
1783 1784
	for (x = 0; x < 32; x++)
		if (test_bit(x, &gh->gh_iflags))
1785 1786 1787 1788 1789 1790
			print_dbg(gi, " %u", x);
	print_dbg(gi, " \n");
	if (gi)
		print_dbg(gi, "    initialized at: 0x%x\n", gh->gh_ip);
	else
		print_symbol(KERN_INFO "    initialized at: %s\n", gh->gh_ip);
D
David Teigland 已提交
1791

1792
	return 0;
D
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1793 1794 1795 1796 1797 1798 1799 1800 1801
}

/**
 * dump_inode - print information about an inode
 * @ip: the inode
 *
 * Returns: 0 on success, -ENOBUFS when we run out of space
 */

1802
static int dump_inode(struct glock_iter *gi, struct gfs2_inode *ip)
D
David Teigland 已提交
1803 1804 1805
{
	unsigned int x;

1806 1807 1808 1809 1810
	print_dbg(gi, "  Inode:\n");
	print_dbg(gi, "    num = %llu/%llu\n",
		    ip->i_num.no_formal_ino, ip->i_num.no_addr);
	print_dbg(gi, "    type = %u\n", IF2DT(ip->i_inode.i_mode));
	print_dbg(gi, "    i_flags =");
D
David Teigland 已提交
1811 1812
	for (x = 0; x < 32; x++)
		if (test_bit(x, &ip->i_flags))
1813 1814 1815
			print_dbg(gi, " %u", x);
	print_dbg(gi, " \n");
	return 0;
D
David Teigland 已提交
1816 1817 1818 1819 1820 1821 1822 1823 1824 1825
}

/**
 * dump_glock - print information about a glock
 * @gl: the glock
 * @count: where we are in the buffer
 *
 * Returns: 0 on success, -ENOBUFS when we run out of space
 */

1826
static int dump_glock(struct glock_iter *gi, struct gfs2_glock *gl)
D
David Teigland 已提交
1827 1828 1829 1830 1831 1832 1833
{
	struct gfs2_holder *gh;
	unsigned int x;
	int error = -ENOBUFS;

	spin_lock(&gl->gl_spin);

1834 1835 1836
	print_dbg(gi, "Glock 0x%p (%u, %llu)\n", gl, gl->gl_name.ln_type,
		   (unsigned long long)gl->gl_name.ln_number);
	print_dbg(gi, "  gl_flags =");
1837
	for (x = 0; x < 32; x++) {
D
David Teigland 已提交
1838
		if (test_bit(x, &gl->gl_flags))
1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850
			print_dbg(gi, " %u", x);
	}
	print_dbg(gi, " \n");
	print_dbg(gi, "  gl_ref = %d\n", atomic_read(&gl->gl_ref));
	print_dbg(gi, "  gl_state = %u\n", gl->gl_state);
	print_dbg(gi, "  gl_owner = %s\n", gl->gl_owner->comm);
	print_dbg(gi, "  gl_ip = %lu\n", gl->gl_ip);
	print_dbg(gi, "  req_gh = %s\n", (gl->gl_req_gh) ? "yes" : "no");
	print_dbg(gi, "  req_bh = %s\n", (gl->gl_req_bh) ? "yes" : "no");
	print_dbg(gi, "  lvb_count = %d\n", atomic_read(&gl->gl_lvb_count));
	print_dbg(gi, "  object = %s\n", (gl->gl_object) ? "yes" : "no");
	print_dbg(gi, "  le = %s\n",
D
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1851
		   (list_empty(&gl->gl_le.le_list)) ? "no" : "yes");
1852 1853
	print_dbg(gi, "  reclaim = %s\n",
		   (list_empty(&gl->gl_reclaim)) ? "no" : "yes");
D
David Teigland 已提交
1854
	if (gl->gl_aspace)
1855 1856
		print_dbg(gi, "  aspace = 0x%p nrpages = %lu\n", gl->gl_aspace,
			   gl->gl_aspace->i_mapping->nrpages);
D
David Teigland 已提交
1857
	else
1858 1859
		print_dbg(gi, "  aspace = no\n");
	print_dbg(gi, "  ail = %d\n", atomic_read(&gl->gl_ail_count));
D
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1860
	if (gl->gl_req_gh) {
1861
		error = dump_holder(gi, "Request", gl->gl_req_gh);
D
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1862 1863 1864 1865
		if (error)
			goto out;
	}
	list_for_each_entry(gh, &gl->gl_holders, gh_list) {
1866
		error = dump_holder(gi, "Holder", gh);
D
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1867 1868 1869 1870
		if (error)
			goto out;
	}
	list_for_each_entry(gh, &gl->gl_waiters1, gh_list) {
1871
		error = dump_holder(gi, "Waiter1", gh);
D
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1872 1873 1874 1875
		if (error)
			goto out;
	}
	list_for_each_entry(gh, &gl->gl_waiters3, gh_list) {
1876
		error = dump_holder(gi, "Waiter3", gh);
D
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1877 1878 1879
		if (error)
			goto out;
	}
1880 1881 1882
	if (test_bit(GLF_DEMOTE, &gl->gl_flags)) {
		print_dbg(gi, "  Demotion req to state %u (%llu uS ago)\n",
			  gl->gl_demote_state,
1883
			  (u64)(jiffies - gl->gl_demote_time)*(1000000/HZ));
1884
	}
1885
	if (gl->gl_ops == &gfs2_inode_glops && gl->gl_object) {
D
David Teigland 已提交
1886
		if (!test_bit(GLF_LOCK, &gl->gl_flags) &&
1887 1888
			list_empty(&gl->gl_holders)) {
			error = dump_inode(gi, gl->gl_object);
D
David Teigland 已提交
1889 1890 1891 1892
			if (error)
				goto out;
		} else {
			error = -ENOBUFS;
1893
			print_dbg(gi, "  Inode: busy\n");
D
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1894 1895 1896 1897 1898
		}
	}

	error = 0;

1899
out:
D
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1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912
	spin_unlock(&gl->gl_spin);
	return error;
}

/**
 * gfs2_dump_lockstate - print out the current lockstate
 * @sdp: the filesystem
 * @ub: the buffer to copy the information into
 *
 * If @ub is NULL, dump the lockstate to the console.
 *
 */

1913
static int gfs2_dump_lockstate(struct gfs2_sbd *sdp)
D
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1914 1915
{
	struct gfs2_glock *gl;
1916
	struct hlist_node *h;
D
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1917 1918 1919 1920 1921
	unsigned int x;
	int error = 0;

	for (x = 0; x < GFS2_GL_HASH_SIZE; x++) {

1922
		read_lock(gl_lock_addr(x));
D
David Teigland 已提交
1923

1924
		hlist_for_each_entry(gl, h, &gl_hash_table[x].hb_list, gl_list) {
1925 1926
			if (gl->gl_sbd != sdp)
				continue;
D
David Teigland 已提交
1927

1928
			error = dump_glock(NULL, gl);
D
David Teigland 已提交
1929 1930 1931 1932
			if (error)
				break;
		}

1933
		read_unlock(gl_lock_addr(x));
D
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1934 1935 1936 1937 1938 1939 1940 1941 1942

		if (error)
			break;
	}


	return error;
}

1943 1944 1945 1946
int __init gfs2_glock_init(void)
{
	unsigned i;
	for(i = 0; i < GFS2_GL_HASH_SIZE; i++) {
1947
		INIT_HLIST_HEAD(&gl_hash_table[i].hb_list);
1948
	}
1949 1950 1951 1952 1953
#ifdef GL_HASH_LOCK_SZ
	for(i = 0; i < GL_HASH_LOCK_SZ; i++) {
		rwlock_init(&gl_hash_locks[i]);
	}
#endif
1954 1955 1956
	return 0;
}

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 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 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 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110
static int gfs2_glock_iter_next(struct glock_iter *gi)
{
	while (1) {
		if (!gi->hb_list) {  /* If we don't have a hash bucket yet */
			gi->hb_list = &gl_hash_table[gi->hash].hb_list;
			if (hlist_empty(gi->hb_list)) {
				gi->hash++;
				gi->hb_list = NULL;
				if (gi->hash >= GFS2_GL_HASH_SIZE)
					return 1;
				else
					continue;
			}
			if (!hlist_empty(gi->hb_list)) {
				gi->gl = list_entry(gi->hb_list->first,
						    struct gfs2_glock,
						    gl_list);
			}
		} else {
			if (gi->gl->gl_list.next == NULL) {
				gi->hash++;
				gi->hb_list = NULL;
				continue;
			}
			gi->gl = list_entry(gi->gl->gl_list.next,
					    struct gfs2_glock, gl_list);
		}
		if (gi->gl)
			break;
	}
	return 0;
}

static void gfs2_glock_iter_free(struct glock_iter *gi)
{
	kfree(gi);
}

static struct glock_iter *gfs2_glock_iter_init(struct gfs2_sbd *sdp)
{
	struct glock_iter *gi;

	gi = kmalloc(sizeof (*gi), GFP_KERNEL);
	if (!gi)
		return NULL;

	gi->sdp = sdp;
	gi->hash = 0;
	gi->gl = NULL;
	gi->hb_list = NULL;
	gi->seq = NULL;
	memset(gi->string, 0, sizeof(gi->string));

	if (gfs2_glock_iter_next(gi)) {
		gfs2_glock_iter_free(gi);
		return NULL;
	}

	return gi;
}

static void *gfs2_glock_seq_start(struct seq_file *file, loff_t *pos)
{
	struct glock_iter *gi;
	loff_t n = *pos;

	gi = gfs2_glock_iter_init(file->private);
	if (!gi)
		return NULL;

	while (n--) {
		if (gfs2_glock_iter_next(gi)) {
			gfs2_glock_iter_free(gi);
			return NULL;
		}
	}

	return gi;
}

static void *gfs2_glock_seq_next(struct seq_file *file, void *iter_ptr,
				 loff_t *pos)
{
	struct glock_iter *gi = iter_ptr;

	(*pos)++;

	if (gfs2_glock_iter_next(gi)) {
		gfs2_glock_iter_free(gi);
		return NULL;
	}

	return gi;
}

static void gfs2_glock_seq_stop(struct seq_file *file, void *iter_ptr)
{
	/* nothing for now */
}

static int gfs2_glock_seq_show(struct seq_file *file, void *iter_ptr)
{
	struct glock_iter *gi = iter_ptr;

	gi->seq = file;
	dump_glock(gi, gi->gl);

	return 0;
}

static struct seq_operations gfs2_glock_seq_ops = {
	.start = gfs2_glock_seq_start,
	.next  = gfs2_glock_seq_next,
	.stop  = gfs2_glock_seq_stop,
	.show  = gfs2_glock_seq_show,
};

static int gfs2_debugfs_open(struct inode *inode, struct file *file)
{
	struct seq_file *seq;
	int ret;

	ret = seq_open(file, &gfs2_glock_seq_ops);
	if (ret)
		return ret;

	seq = file->private_data;
	seq->private = inode->i_private;

	return 0;
}

static const struct file_operations gfs2_debug_fops = {
	.owner   = THIS_MODULE,
	.open    = gfs2_debugfs_open,
	.read    = seq_read,
	.llseek  = seq_lseek,
	.release = seq_release
};

int gfs2_create_debugfs_file(struct gfs2_sbd *sdp)
{
	sdp->debugfs_dentry = debugfs_create_file(sdp->sd_table_name,
						  S_IFREG | S_IRUGO,
						  gfs2_root, sdp,
						  &gfs2_debug_fops);
	if (!sdp->debugfs_dentry)
		return -ENOMEM;

	return 0;
}

void gfs2_delete_debugfs_file(struct gfs2_sbd *sdp)
{
2111
	if (sdp && sdp->debugfs_dentry)
2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124
		debugfs_remove(sdp->debugfs_dentry);
}

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);
}