dlmmaster.c 95.5 KB
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/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * dlmmod.c
 *
 * standalone DLM module
 *
 * Copyright (C) 2004 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 *
 */


#include <linux/module.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/random.h>
#include <linux/blkdev.h>
#include <linux/socket.h>
#include <linux/inet.h>
#include <linux/spinlock.h>
#include <linux/delay.h>


#include "cluster/heartbeat.h"
#include "cluster/nodemanager.h"
#include "cluster/tcp.h"

#include "dlmapi.h"
#include "dlmcommon.h"
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#include "dlmdomain.h"
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#include "dlmdebug.h"
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#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
#include "cluster/masklog.h"

static void dlm_mle_node_down(struct dlm_ctxt *dlm,
			      struct dlm_master_list_entry *mle,
			      struct o2nm_node *node,
			      int idx);
static void dlm_mle_node_up(struct dlm_ctxt *dlm,
			    struct dlm_master_list_entry *mle,
			    struct o2nm_node *node,
			    int idx);

static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
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static int dlm_do_assert_master(struct dlm_ctxt *dlm,
				struct dlm_lock_resource *res,
				void *nodemap, u32 flags);
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static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data);
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static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
				struct dlm_master_list_entry *mle,
				const char *name,
				unsigned int namelen)
{
	if (dlm != mle->dlm)
		return 0;

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	if (namelen != mle->mnamelen ||
	    memcmp(name, mle->mname, namelen) != 0)
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		return 0;

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	return 1;
}

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static struct kmem_cache *dlm_lockres_cache;
static struct kmem_cache *dlm_lockname_cache;
static struct kmem_cache *dlm_mle_cache;
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static void dlm_mle_release(struct kref *kref);
static void dlm_init_mle(struct dlm_master_list_entry *mle,
			enum dlm_mle_type type,
			struct dlm_ctxt *dlm,
			struct dlm_lock_resource *res,
			const char *name,
			unsigned int namelen);
static void dlm_put_mle(struct dlm_master_list_entry *mle);
static void __dlm_put_mle(struct dlm_master_list_entry *mle);
static int dlm_find_mle(struct dlm_ctxt *dlm,
			struct dlm_master_list_entry **mle,
			char *name, unsigned int namelen);

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static int dlm_do_master_request(struct dlm_lock_resource *res,
				 struct dlm_master_list_entry *mle, int to);
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static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
				     struct dlm_lock_resource *res,
				     struct dlm_master_list_entry *mle,
				     int *blocked);
static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
				    struct dlm_lock_resource *res,
				    struct dlm_master_list_entry *mle,
				    int blocked);
static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
				 struct dlm_lock_resource *res,
				 struct dlm_master_list_entry *mle,
				 struct dlm_master_list_entry **oldmle,
				 const char *name, unsigned int namelen,
				 u8 new_master, u8 master);

static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
				    struct dlm_lock_resource *res);
static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
				      struct dlm_lock_resource *res);
static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
				       struct dlm_lock_resource *res,
				       u8 target);
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static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
				       struct dlm_lock_resource *res);
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int dlm_is_host_down(int errno)
{
	switch (errno) {
		case -EBADF:
		case -ECONNREFUSED:
		case -ENOTCONN:
		case -ECONNRESET:
		case -EPIPE:
		case -EHOSTDOWN:
		case -EHOSTUNREACH:
		case -ETIMEDOUT:
		case -ECONNABORTED:
		case -ENETDOWN:
		case -ENETUNREACH:
		case -ENETRESET:
		case -ESHUTDOWN:
		case -ENOPROTOOPT:
		case -EINVAL:   /* if returned from our tcp code,
				   this means there is no socket */
			return 1;
	}
	return 0;
}


/*
 * MASTER LIST FUNCTIONS
 */


/*
 * regarding master list entries and heartbeat callbacks:
 *
 * in order to avoid sleeping and allocation that occurs in
 * heartbeat, master list entries are simply attached to the
 * dlm's established heartbeat callbacks.  the mle is attached
 * when it is created, and since the dlm->spinlock is held at
 * that time, any heartbeat event will be properly discovered
 * by the mle.  the mle needs to be detached from the
 * dlm->mle_hb_events list as soon as heartbeat events are no
 * longer useful to the mle, and before the mle is freed.
 *
 * as a general rule, heartbeat events are no longer needed by
 * the mle once an "answer" regarding the lock master has been
 * received.
 */
static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm,
					      struct dlm_master_list_entry *mle)
{
	assert_spin_locked(&dlm->spinlock);

	list_add_tail(&mle->hb_events, &dlm->mle_hb_events);
}


static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
					      struct dlm_master_list_entry *mle)
{
	if (!list_empty(&mle->hb_events))
		list_del_init(&mle->hb_events);
}


static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
					    struct dlm_master_list_entry *mle)
{
	spin_lock(&dlm->spinlock);
	__dlm_mle_detach_hb_events(dlm, mle);
	spin_unlock(&dlm->spinlock);
}

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static void dlm_get_mle_inuse(struct dlm_master_list_entry *mle)
{
	struct dlm_ctxt *dlm;
	dlm = mle->dlm;

	assert_spin_locked(&dlm->spinlock);
	assert_spin_locked(&dlm->master_lock);
	mle->inuse++;
	kref_get(&mle->mle_refs);
}

static void dlm_put_mle_inuse(struct dlm_master_list_entry *mle)
{
	struct dlm_ctxt *dlm;
	dlm = mle->dlm;

	spin_lock(&dlm->spinlock);
	spin_lock(&dlm->master_lock);
	mle->inuse--;
	__dlm_put_mle(mle);
	spin_unlock(&dlm->master_lock);
	spin_unlock(&dlm->spinlock);

}

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/* remove from list and free */
static void __dlm_put_mle(struct dlm_master_list_entry *mle)
{
	struct dlm_ctxt *dlm;
	dlm = mle->dlm;

	assert_spin_locked(&dlm->spinlock);
	assert_spin_locked(&dlm->master_lock);
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	if (!atomic_read(&mle->mle_refs.refcount)) {
		/* this may or may not crash, but who cares.
		 * it's a BUG. */
		mlog(ML_ERROR, "bad mle: %p\n", mle);
		dlm_print_one_mle(mle);
		BUG();
	} else
		kref_put(&mle->mle_refs, dlm_mle_release);
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}


/* must not have any spinlocks coming in */
static void dlm_put_mle(struct dlm_master_list_entry *mle)
{
	struct dlm_ctxt *dlm;
	dlm = mle->dlm;

	spin_lock(&dlm->spinlock);
	spin_lock(&dlm->master_lock);
	__dlm_put_mle(mle);
	spin_unlock(&dlm->master_lock);
	spin_unlock(&dlm->spinlock);
}

static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
{
	kref_get(&mle->mle_refs);
}

static void dlm_init_mle(struct dlm_master_list_entry *mle,
			enum dlm_mle_type type,
			struct dlm_ctxt *dlm,
			struct dlm_lock_resource *res,
			const char *name,
			unsigned int namelen)
{
	assert_spin_locked(&dlm->spinlock);

	mle->dlm = dlm;
	mle->type = type;
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	INIT_HLIST_NODE(&mle->master_hash_node);
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	INIT_LIST_HEAD(&mle->hb_events);
	memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
	spin_lock_init(&mle->spinlock);
	init_waitqueue_head(&mle->wq);
	atomic_set(&mle->woken, 0);
	kref_init(&mle->mle_refs);
	memset(mle->response_map, 0, sizeof(mle->response_map));
	mle->master = O2NM_MAX_NODES;
	mle->new_master = O2NM_MAX_NODES;
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	mle->inuse = 0;
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	BUG_ON(mle->type != DLM_MLE_BLOCK &&
	       mle->type != DLM_MLE_MASTER &&
	       mle->type != DLM_MLE_MIGRATION);

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	if (mle->type == DLM_MLE_MASTER) {
		BUG_ON(!res);
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		mle->mleres = res;
		memcpy(mle->mname, res->lockname.name, res->lockname.len);
		mle->mnamelen = res->lockname.len;
		mle->mnamehash = res->lockname.hash;
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	} else {
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		BUG_ON(!name);
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		mle->mleres = NULL;
		memcpy(mle->mname, name, namelen);
		mle->mnamelen = namelen;
		mle->mnamehash = dlm_lockid_hash(name, namelen);
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	}

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	atomic_inc(&dlm->mle_tot_count[mle->type]);
	atomic_inc(&dlm->mle_cur_count[mle->type]);

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	/* copy off the node_map and register hb callbacks on our copy */
	memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map));
	memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map));
	clear_bit(dlm->node_num, mle->vote_map);
	clear_bit(dlm->node_num, mle->node_map);

	/* attach the mle to the domain node up/down events */
	__dlm_mle_attach_hb_events(dlm, mle);
}

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void __dlm_unlink_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
{
	assert_spin_locked(&dlm->spinlock);
	assert_spin_locked(&dlm->master_lock);

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	if (!hlist_unhashed(&mle->master_hash_node))
		hlist_del_init(&mle->master_hash_node);
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}

void __dlm_insert_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
{
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	struct hlist_head *bucket;

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	assert_spin_locked(&dlm->master_lock);

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	bucket = dlm_master_hash(dlm, mle->mnamehash);
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	hlist_add_head(&mle->master_hash_node, bucket);
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}
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/* returns 1 if found, 0 if not */
static int dlm_find_mle(struct dlm_ctxt *dlm,
			struct dlm_master_list_entry **mle,
			char *name, unsigned int namelen)
{
	struct dlm_master_list_entry *tmpmle;
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	struct hlist_head *bucket;
	unsigned int hash;
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	assert_spin_locked(&dlm->master_lock);

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	hash = dlm_lockid_hash(name, namelen);
	bucket = dlm_master_hash(dlm, hash);
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	hlist_for_each_entry(tmpmle, bucket, master_hash_node) {
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		if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
			continue;
		dlm_get_mle(tmpmle);
		*mle = tmpmle;
		return 1;
	}
	return 0;
}

void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
{
	struct dlm_master_list_entry *mle;

	assert_spin_locked(&dlm->spinlock);
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	list_for_each_entry(mle, &dlm->mle_hb_events, hb_events) {
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		if (node_up)
			dlm_mle_node_up(dlm, mle, NULL, idx);
		else
			dlm_mle_node_down(dlm, mle, NULL, idx);
	}
}

static void dlm_mle_node_down(struct dlm_ctxt *dlm,
			      struct dlm_master_list_entry *mle,
			      struct o2nm_node *node, int idx)
{
	spin_lock(&mle->spinlock);

	if (!test_bit(idx, mle->node_map))
		mlog(0, "node %u already removed from nodemap!\n", idx);
	else
		clear_bit(idx, mle->node_map);

	spin_unlock(&mle->spinlock);
}

static void dlm_mle_node_up(struct dlm_ctxt *dlm,
			    struct dlm_master_list_entry *mle,
			    struct o2nm_node *node, int idx)
{
	spin_lock(&mle->spinlock);

	if (test_bit(idx, mle->node_map))
		mlog(0, "node %u already in node map!\n", idx);
	else
		set_bit(idx, mle->node_map);

	spin_unlock(&mle->spinlock);
}


int dlm_init_mle_cache(void)
{
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	dlm_mle_cache = kmem_cache_create("o2dlm_mle",
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					  sizeof(struct dlm_master_list_entry),
					  0, SLAB_HWCACHE_ALIGN,
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					  NULL);
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	if (dlm_mle_cache == NULL)
		return -ENOMEM;
	return 0;
}

void dlm_destroy_mle_cache(void)
{
	if (dlm_mle_cache)
		kmem_cache_destroy(dlm_mle_cache);
}

static void dlm_mle_release(struct kref *kref)
{
	struct dlm_master_list_entry *mle;
	struct dlm_ctxt *dlm;

	mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
	dlm = mle->dlm;

	assert_spin_locked(&dlm->spinlock);
	assert_spin_locked(&dlm->master_lock);

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	mlog(0, "Releasing mle for %.*s, type %d\n", mle->mnamelen, mle->mname,
	     mle->type);
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	/* remove from list if not already */
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	__dlm_unlink_mle(dlm, mle);
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	/* detach the mle from the domain node up/down events */
	__dlm_mle_detach_hb_events(dlm, mle);

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	atomic_dec(&dlm->mle_cur_count[mle->type]);

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	/* NOTE: kfree under spinlock here.
	 * if this is bad, we can move this to a freelist. */
	kmem_cache_free(dlm_mle_cache, mle);
}


/*
 * LOCK RESOURCE FUNCTIONS
 */

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int dlm_init_master_caches(void)
{
	dlm_lockres_cache = kmem_cache_create("o2dlm_lockres",
					      sizeof(struct dlm_lock_resource),
					      0, SLAB_HWCACHE_ALIGN, NULL);
	if (!dlm_lockres_cache)
		goto bail;

	dlm_lockname_cache = kmem_cache_create("o2dlm_lockname",
					       DLM_LOCKID_NAME_MAX, 0,
					       SLAB_HWCACHE_ALIGN, NULL);
	if (!dlm_lockname_cache)
		goto bail;

	return 0;
bail:
	dlm_destroy_master_caches();
	return -ENOMEM;
}

void dlm_destroy_master_caches(void)
{
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	if (dlm_lockname_cache) {
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		kmem_cache_destroy(dlm_lockname_cache);
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		dlm_lockname_cache = NULL;
	}
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	if (dlm_lockres_cache) {
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		kmem_cache_destroy(dlm_lockres_cache);
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		dlm_lockres_cache = NULL;
	}
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}

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static void dlm_lockres_release(struct kref *kref)
{
	struct dlm_lock_resource *res;
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	struct dlm_ctxt *dlm;
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	res = container_of(kref, struct dlm_lock_resource, refs);
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	dlm = res->dlm;
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	/* This should not happen -- all lockres' have a name
	 * associated with them at init time. */
	BUG_ON(!res->lockname.name);

	mlog(0, "destroying lockres %.*s\n", res->lockname.len,
	     res->lockname.name);

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	spin_lock(&dlm->track_lock);
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	if (!list_empty(&res->tracking))
		list_del_init(&res->tracking);
	else {
		mlog(ML_ERROR, "Resource %.*s not on the Tracking list\n",
		     res->lockname.len, res->lockname.name);
		dlm_print_one_lock_resource(res);
	}
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	spin_unlock(&dlm->track_lock);

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	atomic_dec(&dlm->res_cur_count);

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	if (!hlist_unhashed(&res->hash_node) ||
	    !list_empty(&res->granted) ||
	    !list_empty(&res->converting) ||
	    !list_empty(&res->blocked) ||
	    !list_empty(&res->dirty) ||
	    !list_empty(&res->recovering) ||
	    !list_empty(&res->purge)) {
		mlog(ML_ERROR,
		     "Going to BUG for resource %.*s."
		     "  We're on a list! [%c%c%c%c%c%c%c]\n",
		     res->lockname.len, res->lockname.name,
		     !hlist_unhashed(&res->hash_node) ? 'H' : ' ',
		     !list_empty(&res->granted) ? 'G' : ' ',
		     !list_empty(&res->converting) ? 'C' : ' ',
		     !list_empty(&res->blocked) ? 'B' : ' ',
		     !list_empty(&res->dirty) ? 'D' : ' ',
		     !list_empty(&res->recovering) ? 'R' : ' ',
		     !list_empty(&res->purge) ? 'P' : ' ');

		dlm_print_one_lock_resource(res);
	}

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	/* By the time we're ready to blow this guy away, we shouldn't
	 * be on any lists. */
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	BUG_ON(!hlist_unhashed(&res->hash_node));
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	BUG_ON(!list_empty(&res->granted));
	BUG_ON(!list_empty(&res->converting));
	BUG_ON(!list_empty(&res->blocked));
	BUG_ON(!list_empty(&res->dirty));
	BUG_ON(!list_empty(&res->recovering));
	BUG_ON(!list_empty(&res->purge));

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	kmem_cache_free(dlm_lockname_cache, (void *)res->lockname.name);
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	kmem_cache_free(dlm_lockres_cache, res);
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}

void dlm_lockres_put(struct dlm_lock_resource *res)
{
	kref_put(&res->refs, dlm_lockres_release);
}

static void dlm_init_lockres(struct dlm_ctxt *dlm,
			     struct dlm_lock_resource *res,
			     const char *name, unsigned int namelen)
{
	char *qname;

	/* If we memset here, we lose our reference to the kmalloc'd
	 * res->lockname.name, so be sure to init every field
	 * correctly! */

	qname = (char *) res->lockname.name;
	memcpy(qname, name, namelen);

	res->lockname.len = namelen;
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	res->lockname.hash = dlm_lockid_hash(name, namelen);
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	init_waitqueue_head(&res->wq);
	spin_lock_init(&res->spinlock);
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	INIT_HLIST_NODE(&res->hash_node);
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	INIT_LIST_HEAD(&res->granted);
	INIT_LIST_HEAD(&res->converting);
	INIT_LIST_HEAD(&res->blocked);
	INIT_LIST_HEAD(&res->dirty);
	INIT_LIST_HEAD(&res->recovering);
	INIT_LIST_HEAD(&res->purge);
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	INIT_LIST_HEAD(&res->tracking);
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	atomic_set(&res->asts_reserved, 0);
	res->migration_pending = 0;
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	res->inflight_locks = 0;
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	res->inflight_assert_workers = 0;
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	res->dlm = dlm;

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	kref_init(&res->refs);

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	atomic_inc(&dlm->res_tot_count);
	atomic_inc(&dlm->res_cur_count);

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	/* just for consistency */
	spin_lock(&res->spinlock);
	dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
	spin_unlock(&res->spinlock);

	res->state = DLM_LOCK_RES_IN_PROGRESS;

	res->last_used = 0;

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	spin_lock(&dlm->spinlock);
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	list_add_tail(&res->tracking, &dlm->tracking_list);
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	spin_unlock(&dlm->spinlock);
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	memset(res->lvb, 0, DLM_LVB_LEN);
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	memset(res->refmap, 0, sizeof(res->refmap));
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}

struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
				   const char *name,
				   unsigned int namelen)
{
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	struct dlm_lock_resource *res = NULL;
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	res = kmem_cache_zalloc(dlm_lockres_cache, GFP_NOFS);
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	if (!res)
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		goto error;
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	res->lockname.name = kmem_cache_zalloc(dlm_lockname_cache, GFP_NOFS);
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	if (!res->lockname.name)
		goto error;
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	dlm_init_lockres(dlm, res, name, namelen);
	return res;
626 627 628 629 630

error:
	if (res)
		kmem_cache_free(dlm_lockres_cache, res);
	return NULL;
631 632
}

633 634
void dlm_lockres_set_refmap_bit(struct dlm_ctxt *dlm,
				struct dlm_lock_resource *res, int bit)
635
{
636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654
	assert_spin_locked(&res->spinlock);

	mlog(0, "res %.*s, set node %u, %ps()\n", res->lockname.len,
	     res->lockname.name, bit, __builtin_return_address(0));

	set_bit(bit, res->refmap);
}

void dlm_lockres_clear_refmap_bit(struct dlm_ctxt *dlm,
				  struct dlm_lock_resource *res, int bit)
{
	assert_spin_locked(&res->spinlock);

	mlog(0, "res %.*s, clr node %u, %ps()\n", res->lockname.len,
	     res->lockname.name, bit, __builtin_return_address(0));

	clear_bit(bit, res->refmap);
}

655
static void __dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
656 657
				   struct dlm_lock_resource *res)
{
658
	res->inflight_locks++;
659

660 661 662
	mlog(0, "%s: res %.*s, inflight++: now %u, %ps()\n", dlm->name,
	     res->lockname.len, res->lockname.name, res->inflight_locks,
	     __builtin_return_address(0));
663 664
}

665 666 667 668 669 670 671
void dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
				   struct dlm_lock_resource *res)
{
	assert_spin_locked(&res->spinlock);
	__dlm_lockres_grab_inflight_ref(dlm, res);
}

672 673
void dlm_lockres_drop_inflight_ref(struct dlm_ctxt *dlm,
				   struct dlm_lock_resource *res)
674 675 676 677
{
	assert_spin_locked(&res->spinlock);

	BUG_ON(res->inflight_locks == 0);
678

679
	res->inflight_locks--;
680

681 682 683 684
	mlog(0, "%s: res %.*s, inflight--: now %u, %ps()\n", dlm->name,
	     res->lockname.len, res->lockname.name, res->inflight_locks,
	     __builtin_return_address(0));

685 686 687
	wake_up(&res->wq);
}

688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724
void __dlm_lockres_grab_inflight_worker(struct dlm_ctxt *dlm,
		struct dlm_lock_resource *res)
{
	assert_spin_locked(&res->spinlock);
	res->inflight_assert_workers++;
	mlog(0, "%s:%.*s: inflight assert worker++: now %u\n",
			dlm->name, res->lockname.len, res->lockname.name,
			res->inflight_assert_workers);
}

static void dlm_lockres_grab_inflight_worker(struct dlm_ctxt *dlm,
		struct dlm_lock_resource *res)
{
	spin_lock(&res->spinlock);
	__dlm_lockres_grab_inflight_worker(dlm, res);
	spin_unlock(&res->spinlock);
}

static void __dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm,
		struct dlm_lock_resource *res)
{
	assert_spin_locked(&res->spinlock);
	BUG_ON(res->inflight_assert_workers == 0);
	res->inflight_assert_workers--;
	mlog(0, "%s:%.*s: inflight assert worker--: now %u\n",
			dlm->name, res->lockname.len, res->lockname.name,
			res->inflight_assert_workers);
}

static void dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm,
		struct dlm_lock_resource *res)
{
	spin_lock(&res->spinlock);
	__dlm_lockres_drop_inflight_worker(dlm, res);
	spin_unlock(&res->spinlock);
}

725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742
/*
 * lookup a lock resource by name.
 * may already exist in the hashtable.
 * lockid is null terminated
 *
 * if not, allocate enough for the lockres and for
 * the temporary structure used in doing the mastering.
 *
 * also, do a lookup in the dlm->master_list to see
 * if another node has begun mastering the same lock.
 * if so, there should be a block entry in there
 * for this name, and we should *not* attempt to master
 * the lock here.   need to wait around for that node
 * to assert_master (or die).
 *
 */
struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
					  const char *lockid,
743
					  int namelen,
744 745 746 747 748 749 750 751
					  int flags)
{
	struct dlm_lock_resource *tmpres=NULL, *res=NULL;
	struct dlm_master_list_entry *mle = NULL;
	struct dlm_master_list_entry *alloc_mle = NULL;
	int blocked = 0;
	int ret, nodenum;
	struct dlm_node_iter iter;
752
	unsigned int hash;
753
	int tries = 0;
K
Kurt Hackel 已提交
754
	int bit, wait_on_recovery = 0;
755 756 757

	BUG_ON(!lockid);

758
	hash = dlm_lockid_hash(lockid, namelen);
759 760 761 762 763

	mlog(0, "get lockres %s (len %d)\n", lockid, namelen);

lookup:
	spin_lock(&dlm->spinlock);
764
	tmpres = __dlm_lookup_lockres_full(dlm, lockid, namelen, hash);
765
	if (tmpres) {
766
		spin_unlock(&dlm->spinlock);
767
		spin_lock(&tmpres->spinlock);
768
		/* Wait on the thread that is mastering the resource */
769 770 771
		if (tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
			__dlm_wait_on_lockres(tmpres);
			BUG_ON(tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN);
772 773 774 775
			spin_unlock(&tmpres->spinlock);
			dlm_lockres_put(tmpres);
			tmpres = NULL;
			goto lookup;
776 777
		}

778 779 780 781 782
		/* Wait on the resource purge to complete before continuing */
		if (tmpres->state & DLM_LOCK_RES_DROPPING_REF) {
			BUG_ON(tmpres->owner == dlm->node_num);
			__dlm_wait_on_lockres_flags(tmpres,
						    DLM_LOCK_RES_DROPPING_REF);
783 784 785 786 787 788
			spin_unlock(&tmpres->spinlock);
			dlm_lockres_put(tmpres);
			tmpres = NULL;
			goto lookup;
		}

789 790 791 792
		/* Grab inflight ref to pin the resource */
		dlm_lockres_grab_inflight_ref(dlm, tmpres);

		spin_unlock(&tmpres->spinlock);
793 794 795 796 797 798 799 800 801 802
		if (res)
			dlm_lockres_put(res);
		res = tmpres;
		goto leave;
	}

	if (!res) {
		spin_unlock(&dlm->spinlock);
		mlog(0, "allocating a new resource\n");
		/* nothing found and we need to allocate one. */
803
		alloc_mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819
		if (!alloc_mle)
			goto leave;
		res = dlm_new_lockres(dlm, lockid, namelen);
		if (!res)
			goto leave;
		goto lookup;
	}

	mlog(0, "no lockres found, allocated our own: %p\n", res);

	if (flags & LKM_LOCAL) {
		/* caller knows it's safe to assume it's not mastered elsewhere
		 * DONE!  return right away */
		spin_lock(&res->spinlock);
		dlm_change_lockres_owner(dlm, res, dlm->node_num);
		__dlm_insert_lockres(dlm, res);
820
		dlm_lockres_grab_inflight_ref(dlm, res);
821 822 823 824 825 826 827 828 829 830 831 832
		spin_unlock(&res->spinlock);
		spin_unlock(&dlm->spinlock);
		/* lockres still marked IN_PROGRESS */
		goto wake_waiters;
	}

	/* check master list to see if another node has started mastering it */
	spin_lock(&dlm->master_lock);

	/* if we found a block, wait for lock to be mastered by another node */
	blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
	if (blocked) {
833
		int mig;
834 835 836
		if (mle->type == DLM_MLE_MASTER) {
			mlog(ML_ERROR, "master entry for nonexistent lock!\n");
			BUG();
837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853
		}
		mig = (mle->type == DLM_MLE_MIGRATION);
		/* if there is a migration in progress, let the migration
		 * finish before continuing.  we can wait for the absence
		 * of the MIGRATION mle: either the migrate finished or
		 * one of the nodes died and the mle was cleaned up.
		 * if there is a BLOCK here, but it already has a master
		 * set, we are too late.  the master does not have a ref
		 * for us in the refmap.  detach the mle and drop it.
		 * either way, go back to the top and start over. */
		if (mig || mle->master != O2NM_MAX_NODES) {
			BUG_ON(mig && mle->master == dlm->node_num);
			/* we arrived too late.  the master does not
			 * have a ref for us. retry. */
			mlog(0, "%s:%.*s: late on %s\n",
			     dlm->name, namelen, lockid,
			     mig ?  "MIGRATION" : "BLOCK");
854 855 856 857
			spin_unlock(&dlm->master_lock);
			spin_unlock(&dlm->spinlock);

			/* master is known, detach */
858 859
			if (!mig)
				dlm_mle_detach_hb_events(dlm, mle);
860 861
			dlm_put_mle(mle);
			mle = NULL;
L
Lucas De Marchi 已提交
862
			/* this is lame, but we can't wait on either
863 864 865 866
			 * the mle or lockres waitqueue here */
			if (mig)
				msleep(100);
			goto lookup;
867 868 869 870 871 872 873 874
		}
	} else {
		/* go ahead and try to master lock on this node */
		mle = alloc_mle;
		/* make sure this does not get freed below */
		alloc_mle = NULL;
		dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
		set_bit(dlm->node_num, mle->maybe_map);
875
		__dlm_insert_mle(dlm, mle);
K
Kurt Hackel 已提交
876 877

		/* still holding the dlm spinlock, check the recovery map
878
		 * to see if there are any nodes that still need to be
K
Kurt Hackel 已提交
879 880 881 882
		 * considered.  these will not appear in the mle nodemap
		 * but they might own this lockres.  wait on them. */
		bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
		if (bit < O2NM_MAX_NODES) {
883 884
			mlog(0, "%s: res %.*s, At least one node (%d) "
			     "to recover before lock mastery can begin\n",
K
Kurt Hackel 已提交
885 886 887
			     dlm->name, namelen, (char *)lockid, bit);
			wait_on_recovery = 1;
		}
888 889 890 891 892 893 894 895 896
	}

	/* at this point there is either a DLM_MLE_BLOCK or a
	 * DLM_MLE_MASTER on the master list, so it's safe to add the
	 * lockres to the hashtable.  anyone who finds the lock will
	 * still have to wait on the IN_PROGRESS. */

	/* finally add the lockres to its hash bucket */
	__dlm_insert_lockres(dlm, res);
897

898 899
	/* since this lockres is new it doesn't not require the spinlock */
	__dlm_lockres_grab_inflight_ref(dlm, res);
900

901 902 903 904
	/* get an extra ref on the mle in case this is a BLOCK
	 * if so, the creator of the BLOCK may try to put the last
	 * ref at this time in the assert master handler, so we
	 * need an extra one to keep from a bad ptr deref. */
K
Kurt Hackel 已提交
905
	dlm_get_mle_inuse(mle);
906 907 908
	spin_unlock(&dlm->master_lock);
	spin_unlock(&dlm->spinlock);

909
redo_request:
K
Kurt Hackel 已提交
910 911 912 913 914
	while (wait_on_recovery) {
		/* any cluster changes that occurred after dropping the
		 * dlm spinlock would be detectable be a change on the mle,
		 * so we only need to clear out the recovery map once. */
		if (dlm_is_recovery_lock(lockid, namelen)) {
915 916
			mlog(0, "%s: Recovery map is not empty, but must "
			     "master $RECOVERY lock now\n", dlm->name);
K
Kurt Hackel 已提交
917 918 919 920 921 922 923 924
			if (!dlm_pre_master_reco_lockres(dlm, res))
				wait_on_recovery = 0;
			else {
				mlog(0, "%s: waiting 500ms for heartbeat state "
				    "change\n", dlm->name);
				msleep(500);
			}
			continue;
925
		}
K
Kurt Hackel 已提交
926 927

		dlm_kick_recovery_thread(dlm);
928
		msleep(1000);
K
Kurt Hackel 已提交
929 930 931 932 933
		dlm_wait_for_recovery(dlm);

		spin_lock(&dlm->spinlock);
		bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
		if (bit < O2NM_MAX_NODES) {
934 935
			mlog(0, "%s: res %.*s, At least one node (%d) "
			     "to recover before lock mastery can begin\n",
K
Kurt Hackel 已提交
936 937 938 939 940
			     dlm->name, namelen, (char *)lockid, bit);
			wait_on_recovery = 1;
		} else
			wait_on_recovery = 0;
		spin_unlock(&dlm->spinlock);
941 942 943

		if (wait_on_recovery)
			dlm_wait_for_node_recovery(dlm, bit, 10000);
K
Kurt Hackel 已提交
944 945
	}

946 947 948 949 950 951 952
	/* must wait for lock to be mastered elsewhere */
	if (blocked)
		goto wait;

	ret = -EINVAL;
	dlm_node_iter_init(mle->vote_map, &iter);
	while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
953
		ret = dlm_do_master_request(res, mle, nodenum);
954 955 956 957
		if (ret < 0)
			mlog_errno(ret);
		if (mle->master != O2NM_MAX_NODES) {
			/* found a master ! */
958 959 960 961 962 963
			if (mle->master <= nodenum)
				break;
			/* if our master request has not reached the master
			 * yet, keep going until it does.  this is how the
			 * master will know that asserts are needed back to
			 * the lower nodes. */
964 965
			mlog(0, "%s: res %.*s, Requests only up to %u but "
			     "master is %u, keep going\n", dlm->name, namelen,
966
			     lockid, nodenum, mle->master);
967 968 969 970 971 972 973
		}
	}

wait:
	/* keep going until the response map includes all nodes */
	ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
	if (ret < 0) {
974
		wait_on_recovery = 1;
975 976
		mlog(0, "%s: res %.*s, Node map changed, redo the master "
		     "request now, blocked=%d\n", dlm->name, res->lockname.len,
977 978
		     res->lockname.name, blocked);
		if (++tries > 20) {
979 980
			mlog(ML_ERROR, "%s: res %.*s, Spinning on "
			     "dlm_wait_for_lock_mastery, blocked = %d\n",
981
			     dlm->name, res->lockname.len,
982 983
			     res->lockname.name, blocked);
			dlm_print_one_lock_resource(res);
984
			dlm_print_one_mle(mle);
985 986 987 988 989
			tries = 0;
		}
		goto redo_request;
	}

990 991
	mlog(0, "%s: res %.*s, Mastered by %u\n", dlm->name, res->lockname.len,
	     res->lockname.name, res->owner);
992 993 994 995 996 997 998
	/* make sure we never continue without this */
	BUG_ON(res->owner == O2NM_MAX_NODES);

	/* master is known, detach if not already detached */
	dlm_mle_detach_hb_events(dlm, mle);
	dlm_put_mle(mle);
	/* put the extra ref */
K
Kurt Hackel 已提交
999
	dlm_put_mle_inuse(mle);
1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034

wake_waiters:
	spin_lock(&res->spinlock);
	res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
	spin_unlock(&res->spinlock);
	wake_up(&res->wq);

leave:
	/* need to free the unused mle */
	if (alloc_mle)
		kmem_cache_free(dlm_mle_cache, alloc_mle);

	return res;
}


#define DLM_MASTERY_TIMEOUT_MS   5000

static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
				     struct dlm_lock_resource *res,
				     struct dlm_master_list_entry *mle,
				     int *blocked)
{
	u8 m;
	int ret, bit;
	int map_changed, voting_done;
	int assert, sleep;

recheck:
	ret = 0;
	assert = 0;

	/* check if another node has already become the owner */
	spin_lock(&res->spinlock);
	if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1035 1036
		mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
		     res->lockname.len, res->lockname.name, res->owner);
1037
		spin_unlock(&res->spinlock);
1038 1039
		/* this will cause the master to re-assert across
		 * the whole cluster, freeing up mles */
1040
		if (res->owner != dlm->node_num) {
1041
			ret = dlm_do_master_request(res, mle, res->owner);
1042 1043 1044 1045 1046 1047
			if (ret < 0) {
				/* give recovery a chance to run */
				mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
				msleep(500);
				goto recheck;
			}
1048 1049
		}
		ret = 0;
1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068
		goto leave;
	}
	spin_unlock(&res->spinlock);

	spin_lock(&mle->spinlock);
	m = mle->master;
	map_changed = (memcmp(mle->vote_map, mle->node_map,
			      sizeof(mle->vote_map)) != 0);
	voting_done = (memcmp(mle->vote_map, mle->response_map,
			     sizeof(mle->vote_map)) == 0);

	/* restart if we hit any errors */
	if (map_changed) {
		int b;
		mlog(0, "%s: %.*s: node map changed, restarting\n",
		     dlm->name, res->lockname.len, res->lockname.name);
		ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
		b = (mle->type == DLM_MLE_BLOCK);
		if ((*blocked && !b) || (!*blocked && b)) {
1069
			mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082
			     dlm->name, res->lockname.len, res->lockname.name,
			     *blocked, b);
			*blocked = b;
		}
		spin_unlock(&mle->spinlock);
		if (ret < 0) {
			mlog_errno(ret);
			goto leave;
		}
		mlog(0, "%s:%.*s: restart lock mastery succeeded, "
		     "rechecking now\n", dlm->name, res->lockname.len,
		     res->lockname.name);
		goto recheck;
K
Kurt Hackel 已提交
1083 1084 1085 1086 1087 1088
	} else {
		if (!voting_done) {
			mlog(0, "map not changed and voting not done "
			     "for %s:%.*s\n", dlm->name, res->lockname.len,
			     res->lockname.name);
		}
1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104
	}

	if (m != O2NM_MAX_NODES) {
		/* another node has done an assert!
		 * all done! */
		sleep = 0;
	} else {
		sleep = 1;
		/* have all nodes responded? */
		if (voting_done && !*blocked) {
			bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
			if (dlm->node_num <= bit) {
				/* my node number is lowest.
			 	 * now tell other nodes that I am
				 * mastering this. */
				mle->master = dlm->node_num;
1105 1106
				/* ref was grabbed in get_lock_resource
				 * will be dropped in dlmlock_master */
1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131
				assert = 1;
				sleep = 0;
			}
			/* if voting is done, but we have not received
			 * an assert master yet, we must sleep */
		}
	}

	spin_unlock(&mle->spinlock);

	/* sleep if we haven't finished voting yet */
	if (sleep) {
		unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);

		/*
		if (atomic_read(&mle->mle_refs.refcount) < 2)
			mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle,
			atomic_read(&mle->mle_refs.refcount),
			res->lockname.len, res->lockname.name);
		*/
		atomic_set(&mle->woken, 0);
		(void)wait_event_timeout(mle->wq,
					 (atomic_read(&mle->woken) == 1),
					 timeo);
		if (res->owner == O2NM_MAX_NODES) {
1132 1133
			mlog(0, "%s:%.*s: waiting again\n", dlm->name,
			     res->lockname.len, res->lockname.name);
1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145
			goto recheck;
		}
		mlog(0, "done waiting, master is %u\n", res->owner);
		ret = 0;
		goto leave;
	}

	ret = 0;   /* done */
	if (assert) {
		m = dlm->node_num;
		mlog(0, "about to master %.*s here, this=%u\n",
		     res->lockname.len, res->lockname.name, m);
1146
		ret = dlm_do_assert_master(dlm, res, mle->vote_map, 0);
1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161
		if (ret) {
			/* This is a failure in the network path,
			 * not in the response to the assert_master
			 * (any nonzero response is a BUG on this node).
			 * Most likely a socket just got disconnected
			 * due to node death. */
			mlog_errno(ret);
		}
		/* no longer need to restart lock mastery.
		 * all living nodes have been contacted. */
		ret = 0;
	}

	/* set the lockres owner */
	spin_lock(&res->spinlock);
1162 1163
	/* mastery reference obtained either during
	 * assert_master_handler or in get_lock_resource */
1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 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 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248
	dlm_change_lockres_owner(dlm, res, m);
	spin_unlock(&res->spinlock);

leave:
	return ret;
}

struct dlm_bitmap_diff_iter
{
	int curnode;
	unsigned long *orig_bm;
	unsigned long *cur_bm;
	unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
};

enum dlm_node_state_change
{
	NODE_DOWN = -1,
	NODE_NO_CHANGE = 0,
	NODE_UP
};

static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
				      unsigned long *orig_bm,
				      unsigned long *cur_bm)
{
	unsigned long p1, p2;
	int i;

	iter->curnode = -1;
	iter->orig_bm = orig_bm;
	iter->cur_bm = cur_bm;

	for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
       		p1 = *(iter->orig_bm + i);
	       	p2 = *(iter->cur_bm + i);
		iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
	}
}

static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
				     enum dlm_node_state_change *state)
{
	int bit;

	if (iter->curnode >= O2NM_MAX_NODES)
		return -ENOENT;

	bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
			    iter->curnode+1);
	if (bit >= O2NM_MAX_NODES) {
		iter->curnode = O2NM_MAX_NODES;
		return -ENOENT;
	}

	/* if it was there in the original then this node died */
	if (test_bit(bit, iter->orig_bm))
		*state = NODE_DOWN;
	else
		*state = NODE_UP;

	iter->curnode = bit;
	return bit;
}


static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
				    struct dlm_lock_resource *res,
				    struct dlm_master_list_entry *mle,
				    int blocked)
{
	struct dlm_bitmap_diff_iter bdi;
	enum dlm_node_state_change sc;
	int node;
	int ret = 0;

	mlog(0, "something happened such that the "
	     "master process may need to be restarted!\n");

	assert_spin_locked(&mle->spinlock);

	dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
	node = dlm_bitmap_diff_iter_next(&bdi, &sc);
	while (node >= 0) {
		if (sc == NODE_UP) {
K
Kurt Hackel 已提交
1249 1250 1251 1252
			/* a node came up.  clear any old vote from
			 * the response map and set it in the vote map
			 * then restart the mastery. */
			mlog(ML_NOTICE, "node %d up while restarting\n", node);
1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266

			/* redo the master request, but only for the new node */
			mlog(0, "sending request to new node\n");
			clear_bit(node, mle->response_map);
			set_bit(node, mle->vote_map);
		} else {
			mlog(ML_ERROR, "node down! %d\n", node);
			if (blocked) {
				int lowest = find_next_bit(mle->maybe_map,
						       O2NM_MAX_NODES, 0);

				/* act like it was never there */
				clear_bit(node, mle->maybe_map);

1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296
			       	if (node == lowest) {
					mlog(0, "expected master %u died"
					    " while this node was blocked "
					    "waiting on it!\n", node);
					lowest = find_next_bit(mle->maybe_map,
						       	O2NM_MAX_NODES,
						       	lowest+1);
					if (lowest < O2NM_MAX_NODES) {
						mlog(0, "%s:%.*s:still "
						     "blocked. waiting on %u "
						     "now\n", dlm->name,
						     res->lockname.len,
						     res->lockname.name,
						     lowest);
					} else {
						/* mle is an MLE_BLOCK, but
						 * there is now nothing left to
						 * block on.  we need to return
						 * all the way back out and try
						 * again with an MLE_MASTER.
						 * dlm_do_local_recovery_cleanup
						 * has already run, so the mle
						 * refcount is ok */
						mlog(0, "%s:%.*s: no "
						     "longer blocking. try to "
						     "master this here\n",
						     dlm->name,
						     res->lockname.len,
						     res->lockname.name);
						mle->type = DLM_MLE_MASTER;
1297
						mle->mleres = res;
1298
					}
1299 1300 1301
				}
			}

1302 1303 1304 1305 1306 1307 1308 1309 1310 1311
			/* now blank out everything, as if we had never
			 * contacted anyone */
			memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
			memset(mle->response_map, 0, sizeof(mle->response_map));
			/* reset the vote_map to the current node_map */
			memcpy(mle->vote_map, mle->node_map,
			       sizeof(mle->node_map));
			/* put myself into the maybe map */
			if (mle->type != DLM_MLE_BLOCK)
				set_bit(dlm->node_num, mle->maybe_map);
1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329
		}
		ret = -EAGAIN;
		node = dlm_bitmap_diff_iter_next(&bdi, &sc);
	}
	return ret;
}


/*
 * DLM_MASTER_REQUEST_MSG
 *
 * returns: 0 on success,
 *          -errno on a network error
 *
 * on error, the caller should assume the target node is "dead"
 *
 */

1330 1331
static int dlm_do_master_request(struct dlm_lock_resource *res,
				 struct dlm_master_list_entry *mle, int to)
1332 1333 1334 1335 1336 1337 1338 1339 1340 1341
{
	struct dlm_ctxt *dlm = mle->dlm;
	struct dlm_master_request request;
	int ret, response=0, resend;

	memset(&request, 0, sizeof(request));
	request.node_idx = dlm->node_num;

	BUG_ON(mle->type == DLM_MLE_MIGRATION);

1342 1343
	request.namelen = (u8)mle->mnamelen;
	memcpy(request.name, mle->mname, request.namelen);
1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380

again:
	ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
				 sizeof(request), to, &response);
	if (ret < 0)  {
		if (ret == -ESRCH) {
			/* should never happen */
			mlog(ML_ERROR, "TCP stack not ready!\n");
			BUG();
		} else if (ret == -EINVAL) {
			mlog(ML_ERROR, "bad args passed to o2net!\n");
			BUG();
		} else if (ret == -ENOMEM) {
			mlog(ML_ERROR, "out of memory while trying to send "
			     "network message!  retrying\n");
			/* this is totally crude */
			msleep(50);
			goto again;
		} else if (!dlm_is_host_down(ret)) {
			/* not a network error. bad. */
			mlog_errno(ret);
			mlog(ML_ERROR, "unhandled error!");
			BUG();
		}
		/* all other errors should be network errors,
		 * and likely indicate node death */
		mlog(ML_ERROR, "link to %d went down!\n", to);
		goto out;
	}

	ret = 0;
	resend = 0;
	spin_lock(&mle->spinlock);
	switch (response) {
		case DLM_MASTER_RESP_YES:
			set_bit(to, mle->response_map);
			mlog(0, "node %u is the master, response=YES\n", to);
1381 1382 1383
			mlog(0, "%s:%.*s: master node %u now knows I have a "
			     "reference\n", dlm->name, res->lockname.len,
			     res->lockname.name, to);
1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423
			mle->master = to;
			break;
		case DLM_MASTER_RESP_NO:
			mlog(0, "node %u not master, response=NO\n", to);
			set_bit(to, mle->response_map);
			break;
		case DLM_MASTER_RESP_MAYBE:
			mlog(0, "node %u not master, response=MAYBE\n", to);
			set_bit(to, mle->response_map);
			set_bit(to, mle->maybe_map);
			break;
		case DLM_MASTER_RESP_ERROR:
			mlog(0, "node %u hit an error, resending\n", to);
			resend = 1;
			response = 0;
			break;
		default:
			mlog(ML_ERROR, "bad response! %u\n", response);
			BUG();
	}
	spin_unlock(&mle->spinlock);
	if (resend) {
		/* this is also totally crude */
		msleep(50);
		goto again;
	}

out:
	return ret;
}

/*
 * locks that can be taken here:
 * dlm->spinlock
 * res->spinlock
 * mle->spinlock
 * dlm->master_list
 *
 * if possible, TRIM THIS DOWN!!!
 */
1424 1425
int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data,
			       void **ret_data)
1426 1427 1428
{
	u8 response = DLM_MASTER_RESP_MAYBE;
	struct dlm_ctxt *dlm = data;
1429
	struct dlm_lock_resource *res = NULL;
1430 1431 1432
	struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
	struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
	char *name;
1433
	unsigned int namelen, hash;
1434 1435
	int found, ret;
	int set_maybe;
1436
	int dispatch_assert = 0;
1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447

	if (!dlm_grab(dlm))
		return DLM_MASTER_RESP_NO;

	if (!dlm_domain_fully_joined(dlm)) {
		response = DLM_MASTER_RESP_NO;
		goto send_response;
	}

	name = request->name;
	namelen = request->namelen;
1448
	hash = dlm_lockid_hash(name, namelen);
1449 1450 1451 1452 1453 1454 1455 1456

	if (namelen > DLM_LOCKID_NAME_MAX) {
		response = DLM_IVBUFLEN;
		goto send_response;
	}

way_up_top:
	spin_lock(&dlm->spinlock);
1457
	res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1458 1459 1460 1461 1462
	if (res) {
		spin_unlock(&dlm->spinlock);

		/* take care of the easy cases up front */
		spin_lock(&res->spinlock);
1463 1464
		if (res->state & (DLM_LOCK_RES_RECOVERING|
				  DLM_LOCK_RES_MIGRATING)) {
1465 1466
			spin_unlock(&res->spinlock);
			mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1467
			     "being recovered/migrated\n");
1468 1469 1470 1471 1472 1473 1474
			response = DLM_MASTER_RESP_ERROR;
			if (mle)
				kmem_cache_free(dlm_mle_cache, mle);
			goto send_response;
		}

		if (res->owner == dlm->node_num) {
1475
			dlm_lockres_set_refmap_bit(dlm, res, request->node_idx);
1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486
			spin_unlock(&res->spinlock);
			response = DLM_MASTER_RESP_YES;
			if (mle)
				kmem_cache_free(dlm_mle_cache, mle);

			/* this node is the owner.
			 * there is some extra work that needs to
			 * happen now.  the requesting node has
			 * caused all nodes up to this one to
			 * create mles.  this node now needs to
			 * go back and clean those up. */
1487
			dispatch_assert = 1;
1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533
			goto send_response;
		} else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
			spin_unlock(&res->spinlock);
			// mlog(0, "node %u is the master\n", res->owner);
			response = DLM_MASTER_RESP_NO;
			if (mle)
				kmem_cache_free(dlm_mle_cache, mle);
			goto send_response;
		}

		/* ok, there is no owner.  either this node is
		 * being blocked, or it is actively trying to
		 * master this lock. */
		if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
			mlog(ML_ERROR, "lock with no owner should be "
			     "in-progress!\n");
			BUG();
		}

		// mlog(0, "lockres is in progress...\n");
		spin_lock(&dlm->master_lock);
		found = dlm_find_mle(dlm, &tmpmle, name, namelen);
		if (!found) {
			mlog(ML_ERROR, "no mle found for this lock!\n");
			BUG();
		}
		set_maybe = 1;
		spin_lock(&tmpmle->spinlock);
		if (tmpmle->type == DLM_MLE_BLOCK) {
			// mlog(0, "this node is waiting for "
			// "lockres to be mastered\n");
			response = DLM_MASTER_RESP_NO;
		} else if (tmpmle->type == DLM_MLE_MIGRATION) {
			mlog(0, "node %u is master, but trying to migrate to "
			     "node %u.\n", tmpmle->master, tmpmle->new_master);
			if (tmpmle->master == dlm->node_num) {
				mlog(ML_ERROR, "no owner on lockres, but this "
				     "node is trying to migrate it to %u?!\n",
				     tmpmle->new_master);
				BUG();
			} else {
				/* the real master can respond on its own */
				response = DLM_MASTER_RESP_NO;
			}
		} else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
			set_maybe = 0;
1534
			if (tmpmle->master == dlm->node_num) {
1535
				response = DLM_MASTER_RESP_YES;
1536 1537 1538 1539
				/* this node will be the owner.
				 * go back and clean the mles on any
				 * other nodes */
				dispatch_assert = 1;
1540 1541
				dlm_lockres_set_refmap_bit(dlm, res,
							   request->node_idx);
1542
			} else
1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577
				response = DLM_MASTER_RESP_NO;
		} else {
			// mlog(0, "this node is attempting to "
			// "master lockres\n");
			response = DLM_MASTER_RESP_MAYBE;
		}
		if (set_maybe)
			set_bit(request->node_idx, tmpmle->maybe_map);
		spin_unlock(&tmpmle->spinlock);

		spin_unlock(&dlm->master_lock);
		spin_unlock(&res->spinlock);

		/* keep the mle attached to heartbeat events */
		dlm_put_mle(tmpmle);
		if (mle)
			kmem_cache_free(dlm_mle_cache, mle);
		goto send_response;
	}

	/*
	 * lockres doesn't exist on this node
	 * if there is an MLE_BLOCK, return NO
	 * if there is an MLE_MASTER, return MAYBE
	 * otherwise, add an MLE_BLOCK, return NO
	 */
	spin_lock(&dlm->master_lock);
	found = dlm_find_mle(dlm, &tmpmle, name, namelen);
	if (!found) {
		/* this lockid has never been seen on this node yet */
		// mlog(0, "no mle found\n");
		if (!mle) {
			spin_unlock(&dlm->master_lock);
			spin_unlock(&dlm->spinlock);

1578
			mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
1579 1580
			if (!mle) {
				response = DLM_MASTER_RESP_ERROR;
1581
				mlog_errno(-ENOMEM);
1582 1583 1584 1585 1586 1587 1588
				goto send_response;
			}
			goto way_up_top;
		}

		// mlog(0, "this is second time thru, already allocated, "
		// "add the block.\n");
1589
		dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen);
1590
		set_bit(request->node_idx, mle->maybe_map);
1591
		__dlm_insert_mle(dlm, mle);
1592 1593 1594 1595 1596
		response = DLM_MASTER_RESP_NO;
	} else {
		// mlog(0, "mle was found\n");
		set_maybe = 1;
		spin_lock(&tmpmle->spinlock);
1597 1598 1599 1600
		if (tmpmle->master == dlm->node_num) {
			mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
			BUG();
		}
1601 1602 1603 1604 1605 1606 1607
		if (tmpmle->type == DLM_MLE_BLOCK)
			response = DLM_MASTER_RESP_NO;
		else if (tmpmle->type == DLM_MLE_MIGRATION) {
			mlog(0, "migration mle was found (%u->%u)\n",
			     tmpmle->master, tmpmle->new_master);
			/* real master can respond on its own */
			response = DLM_MASTER_RESP_NO;
1608 1609
		} else
			response = DLM_MASTER_RESP_MAYBE;
1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621
		if (set_maybe)
			set_bit(request->node_idx, tmpmle->maybe_map);
		spin_unlock(&tmpmle->spinlock);
	}
	spin_unlock(&dlm->master_lock);
	spin_unlock(&dlm->spinlock);

	if (found) {
		/* keep the mle attached to heartbeat events */
		dlm_put_mle(tmpmle);
	}
send_response:
1622 1623 1624 1625 1626 1627
	/*
	 * __dlm_lookup_lockres() grabbed a reference to this lockres.
	 * The reference is released by dlm_assert_master_worker() under
	 * the call to dlm_dispatch_assert_master().  If
	 * dlm_assert_master_worker() isn't called, we drop it here.
	 */
1628 1629 1630 1631 1632 1633 1634 1635 1636
	if (dispatch_assert) {
		if (response != DLM_MASTER_RESP_YES)
			mlog(ML_ERROR, "invalid response %d\n", response);
		if (!res) {
			mlog(ML_ERROR, "bad lockres while trying to assert!\n");
			BUG();
		}
		mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
			     dlm->node_num, res->lockname.len, res->lockname.name);
1637
		ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1638 1639 1640 1641
						 DLM_ASSERT_MASTER_MLE_CLEANUP);
		if (ret < 0) {
			mlog(ML_ERROR, "failed to dispatch assert master work\n");
			response = DLM_MASTER_RESP_ERROR;
1642
			dlm_lockres_put(res);
1643 1644
		} else
			dlm_lockres_grab_inflight_worker(dlm, res);
1645 1646 1647
	} else {
		if (res)
			dlm_lockres_put(res);
1648 1649
	}

1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663
	dlm_put(dlm);
	return response;
}

/*
 * DLM_ASSERT_MASTER_MSG
 */


/*
 * NOTE: this can be used for debugging
 * can periodically run all locks owned by this node
 * and re-assert across the cluster...
 */
1664 1665 1666
static int dlm_do_assert_master(struct dlm_ctxt *dlm,
				struct dlm_lock_resource *res,
				void *nodemap, u32 flags)
1667 1668 1669 1670 1671
{
	struct dlm_assert_master assert;
	int to, tmpret;
	struct dlm_node_iter iter;
	int ret = 0;
1672
	int reassert;
1673 1674
	const char *lockname = res->lockname.name;
	unsigned int namelen = res->lockname.len;
1675 1676

	BUG_ON(namelen > O2NM_MAX_NAME_LEN);
1677 1678 1679 1680 1681

	spin_lock(&res->spinlock);
	res->state |= DLM_LOCK_RES_SETREF_INPROG;
	spin_unlock(&res->spinlock);

1682 1683
again:
	reassert = 0;
1684 1685 1686 1687 1688

	/* note that if this nodemap is empty, it returns 0 */
	dlm_node_iter_init(nodemap, &iter);
	while ((to = dlm_node_iter_next(&iter)) >= 0) {
		int r = 0;
1689 1690
		struct dlm_master_list_entry *mle = NULL;

1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701
		mlog(0, "sending assert master to %d (%.*s)\n", to,
		     namelen, lockname);
		memset(&assert, 0, sizeof(assert));
		assert.node_idx = dlm->node_num;
		assert.namelen = namelen;
		memcpy(assert.name, lockname, namelen);
		assert.flags = cpu_to_be32(flags);

		tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
					    &assert, sizeof(assert), to, &r);
		if (tmpret < 0) {
1702 1703 1704
			mlog(ML_ERROR, "Error %d when sending message %u (key "
			     "0x%x) to node %u\n", tmpret,
			     DLM_ASSERT_MASTER_MSG, dlm->key, to);
1705
			if (!dlm_is_host_down(tmpret)) {
1706
				mlog(ML_ERROR, "unhandled error=%d!\n", tmpret);
1707 1708 1709
				BUG();
			}
			/* a node died.  finish out the rest of the nodes. */
1710
			mlog(0, "link to %d went down!\n", to);
1711 1712
			/* any nonzero status return will do */
			ret = tmpret;
1713
			r = 0;
1714 1715 1716 1717
		} else if (r < 0) {
			/* ok, something horribly messed.  kill thyself. */
			mlog(ML_ERROR,"during assert master of %.*s to %u, "
			     "got %d.\n", namelen, lockname, to, r);
1718 1719 1720 1721 1722 1723 1724 1725 1726
			spin_lock(&dlm->spinlock);
			spin_lock(&dlm->master_lock);
			if (dlm_find_mle(dlm, &mle, (char *)lockname,
					 namelen)) {
				dlm_print_one_mle(mle);
				__dlm_put_mle(mle);
			}
			spin_unlock(&dlm->master_lock);
			spin_unlock(&dlm->spinlock);
1727
			BUG();
1728 1729 1730 1731 1732 1733 1734 1735 1736 1737
		}

		if (r & DLM_ASSERT_RESPONSE_REASSERT &&
		    !(r & DLM_ASSERT_RESPONSE_MASTERY_REF)) {
				mlog(ML_ERROR, "%.*s: very strange, "
				     "master MLE but no lockres on %u\n",
				     namelen, lockname, to);
		}

		if (r & DLM_ASSERT_RESPONSE_REASSERT) {
1738
			mlog(0, "%.*s: node %u create mles on other "
1739
			     "nodes and requests a re-assert\n",
1740 1741
			     namelen, lockname, to);
			reassert = 1;
1742
		}
1743 1744 1745 1746 1747
		if (r & DLM_ASSERT_RESPONSE_MASTERY_REF) {
			mlog(0, "%.*s: node %u has a reference to this "
			     "lockres, set the bit in the refmap\n",
			     namelen, lockname, to);
			spin_lock(&res->spinlock);
1748
			dlm_lockres_set_refmap_bit(dlm, res, to);
1749 1750
			spin_unlock(&res->spinlock);
		}
1751 1752
	}

1753 1754 1755
	if (reassert)
		goto again;

1756 1757 1758 1759 1760
	spin_lock(&res->spinlock);
	res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
	spin_unlock(&res->spinlock);
	wake_up(&res->wq);

1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772
	return ret;
}

/*
 * locks that can be taken here:
 * dlm->spinlock
 * res->spinlock
 * mle->spinlock
 * dlm->master_list
 *
 * if possible, TRIM THIS DOWN!!!
 */
1773 1774
int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data,
			      void **ret_data)
1775 1776 1777 1778 1779 1780
{
	struct dlm_ctxt *dlm = data;
	struct dlm_master_list_entry *mle = NULL;
	struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
	struct dlm_lock_resource *res = NULL;
	char *name;
1781
	unsigned int namelen, hash;
1782
	u32 flags;
1783
	int master_request = 0, have_lockres_ref = 0;
1784
	int ret = 0;
1785 1786 1787 1788 1789 1790

	if (!dlm_grab(dlm))
		return 0;

	name = assert->name;
	namelen = assert->namelen;
1791
	hash = dlm_lockid_hash(name, namelen);
1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815
	flags = be32_to_cpu(assert->flags);

	if (namelen > DLM_LOCKID_NAME_MAX) {
		mlog(ML_ERROR, "Invalid name length!");
		goto done;
	}

	spin_lock(&dlm->spinlock);

	if (flags)
		mlog(0, "assert_master with flags: %u\n", flags);

	/* find the MLE */
	spin_lock(&dlm->master_lock);
	if (!dlm_find_mle(dlm, &mle, name, namelen)) {
		/* not an error, could be master just re-asserting */
		mlog(0, "just got an assert_master from %u, but no "
		     "MLE for it! (%.*s)\n", assert->node_idx,
		     namelen, name);
	} else {
		int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
		if (bit >= O2NM_MAX_NODES) {
			/* not necessarily an error, though less likely.
			 * could be master just re-asserting. */
K
Kurt Hackel 已提交
1816
			mlog(0, "no bits set in the maybe_map, but %u "
1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827
			     "is asserting! (%.*s)\n", assert->node_idx,
			     namelen, name);
		} else if (bit != assert->node_idx) {
			if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
				mlog(0, "master %u was found, %u should "
				     "back off\n", assert->node_idx, bit);
			} else {
				/* with the fix for bug 569, a higher node
				 * number winning the mastery will respond
				 * YES to mastery requests, but this node
				 * had no way of knowing.  let it pass. */
K
Kurt Hackel 已提交
1828
				mlog(0, "%u is the lowest node, "
1829 1830 1831 1832 1833 1834
				     "%u is asserting. (%.*s)  %u must "
				     "have begun after %u won.\n", bit,
				     assert->node_idx, namelen, name, bit,
				     assert->node_idx);
			}
		}
1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849
		if (mle->type == DLM_MLE_MIGRATION) {
			if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
				mlog(0, "%s:%.*s: got cleanup assert"
				     " from %u for migration\n",
				     dlm->name, namelen, name,
				     assert->node_idx);
			} else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
				mlog(0, "%s:%.*s: got unrelated assert"
				     " from %u for migration, ignoring\n",
				     dlm->name, namelen, name,
				     assert->node_idx);
				__dlm_put_mle(mle);
				spin_unlock(&dlm->master_lock);
				spin_unlock(&dlm->spinlock);
				goto done;
1850
			}
1851
		}
1852 1853 1854 1855 1856
	}
	spin_unlock(&dlm->master_lock);

	/* ok everything checks out with the MLE
	 * now check to see if there is a lockres */
1857
	res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1858 1859 1860 1861 1862 1863 1864 1865
	if (res) {
		spin_lock(&res->spinlock);
		if (res->state & DLM_LOCK_RES_RECOVERING)  {
			mlog(ML_ERROR, "%u asserting but %.*s is "
			     "RECOVERING!\n", assert->node_idx, namelen, name);
			goto kill;
		}
		if (!mle) {
1866 1867
			if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
			    res->owner != assert->node_idx) {
1868 1869 1870 1871 1872 1873
				mlog(ML_ERROR, "DIE! Mastery assert from %u, "
				     "but current owner is %u! (%.*s)\n",
				     assert->node_idx, res->owner, namelen,
				     name);
				__dlm_print_one_lock_resource(res);
				BUG();
1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916
			}
		} else if (mle->type != DLM_MLE_MIGRATION) {
			if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
				/* owner is just re-asserting */
				if (res->owner == assert->node_idx) {
					mlog(0, "owner %u re-asserting on "
					     "lock %.*s\n", assert->node_idx,
					     namelen, name);
					goto ok;
				}
				mlog(ML_ERROR, "got assert_master from "
				     "node %u, but %u is the owner! "
				     "(%.*s)\n", assert->node_idx,
				     res->owner, namelen, name);
				goto kill;
			}
			if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
				mlog(ML_ERROR, "got assert from %u, but lock "
				     "with no owner should be "
				     "in-progress! (%.*s)\n",
				     assert->node_idx,
				     namelen, name);
				goto kill;
			}
		} else /* mle->type == DLM_MLE_MIGRATION */ {
			/* should only be getting an assert from new master */
			if (assert->node_idx != mle->new_master) {
				mlog(ML_ERROR, "got assert from %u, but "
				     "new master is %u, and old master "
				     "was %u (%.*s)\n",
				     assert->node_idx, mle->new_master,
				     mle->master, namelen, name);
				goto kill;
			}

		}
ok:
		spin_unlock(&res->spinlock);
	}

	// mlog(0, "woo!  got an assert_master from node %u!\n",
	// 	     assert->node_idx);
	if (mle) {
1917 1918
		int extra_ref = 0;
		int nn = -1;
K
Kurt Hackel 已提交
1919
		int rr, err = 0;
1920

1921
		spin_lock(&mle->spinlock);
1922 1923 1924 1925 1926 1927
		if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
			extra_ref = 1;
		else {
			/* MASTER mle: if any bits set in the response map
			 * then the calling node needs to re-assert to clear
			 * up nodes that this node contacted */
1928
			while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1929
						    nn+1)) < O2NM_MAX_NODES) {
J
Junxiao Bi 已提交
1930
				if (nn != dlm->node_num && nn != assert->node_idx) {
1931
					master_request = 1;
J
Junxiao Bi 已提交
1932 1933
					break;
				}
1934 1935
			}
		}
1936 1937 1938 1939 1940
		mle->master = assert->node_idx;
		atomic_set(&mle->woken, 1);
		wake_up(&mle->wq);
		spin_unlock(&mle->spinlock);

K
Kurt Hackel 已提交
1941
		if (res) {
1942
			int wake = 0;
1943
			spin_lock(&res->spinlock);
K
Kurt Hackel 已提交
1944 1945 1946 1947 1948 1949
			if (mle->type == DLM_MLE_MIGRATION) {
				mlog(0, "finishing off migration of lockres %.*s, "
			     		"from %u to %u\n",
			       		res->lockname.len, res->lockname.name,
			       		dlm->node_num, mle->new_master);
				res->state &= ~DLM_LOCK_RES_MIGRATING;
1950
				wake = 1;
K
Kurt Hackel 已提交
1951 1952 1953 1954 1955
				dlm_change_lockres_owner(dlm, res, mle->new_master);
				BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
			} else {
				dlm_change_lockres_owner(dlm, res, mle->master);
			}
1956
			spin_unlock(&res->spinlock);
1957
			have_lockres_ref = 1;
1958 1959
			if (wake)
				wake_up(&res->wq);
1960
		}
K
Kurt Hackel 已提交
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

		/* master is known, detach if not already detached.
		 * ensures that only one assert_master call will happen
		 * on this mle. */
		spin_lock(&dlm->master_lock);

		rr = atomic_read(&mle->mle_refs.refcount);
		if (mle->inuse > 0) {
			if (extra_ref && rr < 3)
				err = 1;
			else if (!extra_ref && rr < 2)
				err = 1;
		} else {
			if (extra_ref && rr < 2)
				err = 1;
			else if (!extra_ref && rr < 1)
				err = 1;
		}
		if (err) {
			mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
			     "that will mess up this node, refs=%d, extra=%d, "
			     "inuse=%d\n", dlm->name, namelen, name,
			     assert->node_idx, rr, extra_ref, mle->inuse);
			dlm_print_one_mle(mle);
		}
1986
		__dlm_unlink_mle(dlm, mle);
K
Kurt Hackel 已提交
1987 1988
		__dlm_mle_detach_hb_events(dlm, mle);
		__dlm_put_mle(mle);
1989 1990 1991 1992 1993
		if (extra_ref) {
			/* the assert master message now balances the extra
		 	 * ref given by the master / migration request message.
		 	 * if this is the last put, it will be removed
		 	 * from the list. */
K
Kurt Hackel 已提交
1994 1995 1996 1997 1998 1999 2000 2001
			__dlm_put_mle(mle);
		}
		spin_unlock(&dlm->master_lock);
	} else if (res) {
		if (res->owner != assert->node_idx) {
			mlog(0, "assert_master from %u, but current "
			     "owner is %u (%.*s), no mle\n", assert->node_idx,
			     res->owner, namelen, name);
2002 2003
		}
	}
2004
	spin_unlock(&dlm->spinlock);
2005 2006

done:
2007
	ret = 0;
2008 2009 2010 2011 2012 2013
	if (res) {
		spin_lock(&res->spinlock);
		res->state |= DLM_LOCK_RES_SETREF_INPROG;
		spin_unlock(&res->spinlock);
		*ret_data = (void *)res;
	}
2014
	dlm_put(dlm);
2015 2016
	if (master_request) {
		mlog(0, "need to tell master to reassert\n");
2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029
		/* positive. negative would shoot down the node. */
		ret |= DLM_ASSERT_RESPONSE_REASSERT;
		if (!have_lockres_ref) {
			mlog(ML_ERROR, "strange, got assert from %u, MASTER "
			     "mle present here for %s:%.*s, but no lockres!\n",
			     assert->node_idx, dlm->name, namelen, name);
		}
	}
	if (have_lockres_ref) {
		/* let the master know we have a reference to the lockres */
		ret |= DLM_ASSERT_RESPONSE_MASTERY_REF;
		mlog(0, "%s:%.*s: got assert from %u, need a ref\n",
		     dlm->name, namelen, name, assert->node_idx);
2030 2031
	}
	return ret;
2032 2033 2034

kill:
	/* kill the caller! */
2035 2036 2037
	mlog(ML_ERROR, "Bad message received from another node.  Dumping state "
	     "and killing the other node now!  This node is OK and can continue.\n");
	__dlm_print_one_lock_resource(res);
2038
	spin_unlock(&res->spinlock);
2039 2040 2041 2042
	spin_lock(&dlm->master_lock);
	if (mle)
		__dlm_put_mle(mle);
	spin_unlock(&dlm->master_lock);
2043
	spin_unlock(&dlm->spinlock);
2044
	*ret_data = (void *)res;
2045 2046 2047 2048
	dlm_put(dlm);
	return -EINVAL;
}

2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062
void dlm_assert_master_post_handler(int status, void *data, void *ret_data)
{
	struct dlm_lock_resource *res = (struct dlm_lock_resource *)ret_data;

	if (ret_data) {
		spin_lock(&res->spinlock);
		res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
		spin_unlock(&res->spinlock);
		wake_up(&res->wq);
		dlm_lockres_put(res);
	}
	return;
}

2063 2064 2065 2066 2067
int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
			       struct dlm_lock_resource *res,
			       int ignore_higher, u8 request_from, u32 flags)
{
	struct dlm_work_item *item;
2068
	item = kzalloc(sizeof(*item), GFP_ATOMIC);
2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081
	if (!item)
		return -ENOMEM;


	/* queue up work for dlm_assert_master_worker */
	dlm_grab(dlm);  /* get an extra ref for the work item */
	dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
	item->u.am.lockres = res; /* already have a ref */
	/* can optionally ignore node numbers higher than this node */
	item->u.am.ignore_higher = ignore_higher;
	item->u.am.request_from = request_from;
	item->u.am.flags = flags;

2082 2083
	if (ignore_higher)
		mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
2084
		     res->lockname.name);
2085

2086 2087 2088 2089
	spin_lock(&dlm->work_lock);
	list_add_tail(&item->list, &dlm->work_list);
	spin_unlock(&dlm->work_lock);

2090
	queue_work(dlm->dlm_worker, &dlm->dispatched_work);
2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130
	return 0;
}

static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
{
	struct dlm_ctxt *dlm = data;
	int ret = 0;
	struct dlm_lock_resource *res;
	unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
	int ignore_higher;
	int bit;
	u8 request_from;
	u32 flags;

	dlm = item->dlm;
	res = item->u.am.lockres;
	ignore_higher = item->u.am.ignore_higher;
	request_from = item->u.am.request_from;
	flags = item->u.am.flags;

	spin_lock(&dlm->spinlock);
	memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
	spin_unlock(&dlm->spinlock);

	clear_bit(dlm->node_num, nodemap);
	if (ignore_higher) {
		/* if is this just to clear up mles for nodes below
		 * this node, do not send the message to the original
		 * caller or any node number higher than this */
		clear_bit(request_from, nodemap);
		bit = dlm->node_num;
		while (1) {
			bit = find_next_bit(nodemap, O2NM_MAX_NODES,
					    bit+1);
		       	if (bit >= O2NM_MAX_NODES)
				break;
			clear_bit(bit, nodemap);
		}
	}

2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147
	/*
	 * If we're migrating this lock to someone else, we are no
	 * longer allowed to assert out own mastery.  OTOH, we need to
	 * prevent migration from starting while we're still asserting
	 * our dominance.  The reserved ast delays migration.
	 */
	spin_lock(&res->spinlock);
	if (res->state & DLM_LOCK_RES_MIGRATING) {
		mlog(0, "Someone asked us to assert mastery, but we're "
		     "in the middle of migration.  Skipping assert, "
		     "the new master will handle that.\n");
		spin_unlock(&res->spinlock);
		goto put;
	} else
		__dlm_lockres_reserve_ast(res);
	spin_unlock(&res->spinlock);

2148 2149 2150 2151
	/* this call now finishes out the nodemap
	 * even if one or more nodes die */
	mlog(0, "worker about to master %.*s here, this=%u\n",
		     res->lockname.len, res->lockname.name, dlm->node_num);
2152
	ret = dlm_do_assert_master(dlm, res, nodemap, flags);
2153 2154
	if (ret < 0) {
		/* no need to restart, we are done */
2155 2156
		if (!dlm_is_host_down(ret))
			mlog_errno(ret);
2157 2158
	}

2159 2160 2161 2162
	/* Ok, we've asserted ourselves.  Let's let migration start. */
	dlm_lockres_release_ast(dlm, res);

put:
2163 2164
	dlm_lockres_drop_inflight_worker(dlm, res);

2165 2166 2167 2168 2169
	dlm_lockres_put(res);

	mlog(0, "finished with dlm_assert_master_worker\n");
}

K
Kurt Hackel 已提交
2170 2171 2172 2173 2174 2175 2176
/* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
 * We cannot wait for node recovery to complete to begin mastering this
 * lockres because this lockres is used to kick off recovery! ;-)
 * So, do a pre-check on all living nodes to see if any of those nodes
 * think that $RECOVERY is currently mastered by a dead node.  If so,
 * we wait a short time to allow that node to get notified by its own
 * heartbeat stack, then check again.  All $RECOVERY lock resources
2177
 * mastered by dead nodes are purged when the hearbeat callback is
K
Kurt Hackel 已提交
2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202
 * fired, so we can know for sure that it is safe to continue once
 * the node returns a live node or no node.  */
static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
				       struct dlm_lock_resource *res)
{
	struct dlm_node_iter iter;
	int nodenum;
	int ret = 0;
	u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;

	spin_lock(&dlm->spinlock);
	dlm_node_iter_init(dlm->domain_map, &iter);
	spin_unlock(&dlm->spinlock);

	while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
		/* do not send to self */
		if (nodenum == dlm->node_num)
			continue;
		ret = dlm_do_master_requery(dlm, res, nodenum, &master);
		if (ret < 0) {
			mlog_errno(ret);
			if (!dlm_is_host_down(ret))
				BUG();
			/* host is down, so answer for that node would be
			 * DLM_LOCK_RES_OWNER_UNKNOWN.  continue. */
2203
			ret = 0;
K
Kurt Hackel 已提交
2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217
		}

		if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
			/* check to see if this master is in the recovery map */
			spin_lock(&dlm->spinlock);
			if (test_bit(master, dlm->recovery_map)) {
				mlog(ML_NOTICE, "%s: node %u has not seen "
				     "node %u go down yet, and thinks the "
				     "dead node is mastering the recovery "
				     "lock.  must wait.\n", dlm->name,
				     nodenum, master);
				ret = -EAGAIN;
			}
			spin_unlock(&dlm->spinlock);
2218
			mlog(0, "%s: reco lock master is %u\n", dlm->name,
K
Kurt Hackel 已提交
2219 2220 2221 2222 2223 2224 2225
			     master);
			break;
		}
	}
	return ret;
}

2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248
/*
 * DLM_DEREF_LOCKRES_MSG
 */

int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
{
	struct dlm_deref_lockres deref;
	int ret = 0, r;
	const char *lockname;
	unsigned int namelen;

	lockname = res->lockname.name;
	namelen = res->lockname.len;
	BUG_ON(namelen > O2NM_MAX_NAME_LEN);

	memset(&deref, 0, sizeof(deref));
	deref.node_idx = dlm->node_num;
	deref.namelen = namelen;
	memcpy(deref.name, lockname, namelen);

	ret = o2net_send_message(DLM_DEREF_LOCKRES_MSG, dlm->key,
				 &deref, sizeof(deref), res->owner, &r);
	if (ret < 0)
2249 2250
		mlog(ML_ERROR, "%s: res %.*s, error %d send DEREF to node %u\n",
		     dlm->name, namelen, lockname, ret, res->owner);
2251 2252
	else if (r < 0) {
		/* BAD.  other node says I did not have a ref. */
2253 2254
		mlog(ML_ERROR, "%s: res %.*s, DEREF to node %u got %d\n",
		     dlm->name, namelen, lockname, res->owner, r);
2255 2256 2257 2258 2259 2260
		dlm_print_one_lock_resource(res);
		BUG();
	}
	return ret;
}

2261 2262
int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
			      void **ret_data)
2263 2264 2265 2266 2267 2268 2269 2270 2271
{
	struct dlm_ctxt *dlm = data;
	struct dlm_deref_lockres *deref = (struct dlm_deref_lockres *)msg->buf;
	struct dlm_lock_resource *res = NULL;
	char *name;
	unsigned int namelen;
	int ret = -EINVAL;
	u8 node;
	unsigned int hash;
2272 2273 2274
	struct dlm_work_item *item;
	int cleared = 0;
	int dispatch = 0;
2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304

	if (!dlm_grab(dlm))
		return 0;

	name = deref->name;
	namelen = deref->namelen;
	node = deref->node_idx;

	if (namelen > DLM_LOCKID_NAME_MAX) {
		mlog(ML_ERROR, "Invalid name length!");
		goto done;
	}
	if (deref->node_idx >= O2NM_MAX_NODES) {
		mlog(ML_ERROR, "Invalid node number: %u\n", node);
		goto done;
	}

	hash = dlm_lockid_hash(name, namelen);

	spin_lock(&dlm->spinlock);
	res = __dlm_lookup_lockres_full(dlm, name, namelen, hash);
	if (!res) {
		spin_unlock(&dlm->spinlock);
		mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
		     dlm->name, namelen, name);
		goto done;
	}
	spin_unlock(&dlm->spinlock);

	spin_lock(&res->spinlock);
2305 2306 2307 2308 2309
	if (res->state & DLM_LOCK_RES_SETREF_INPROG)
		dispatch = 1;
	else {
		BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
		if (test_bit(node, res->refmap)) {
2310
			dlm_lockres_clear_refmap_bit(dlm, res, node);
2311 2312
			cleared = 1;
		}
2313 2314 2315
	}
	spin_unlock(&res->spinlock);

2316 2317 2318 2319 2320 2321 2322
	if (!dispatch) {
		if (cleared)
			dlm_lockres_calc_usage(dlm, res);
		else {
			mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
		     	"but it is already dropped!\n", dlm->name,
		     	res->lockname.len, res->lockname.name, node);
2323
			dlm_print_one_lock_resource(res);
2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346
		}
		ret = 0;
		goto done;
	}

	item = kzalloc(sizeof(*item), GFP_NOFS);
	if (!item) {
		ret = -ENOMEM;
		mlog_errno(ret);
		goto done;
	}

	dlm_init_work_item(dlm, item, dlm_deref_lockres_worker, NULL);
	item->u.dl.deref_res = res;
	item->u.dl.deref_node = node;

	spin_lock(&dlm->work_lock);
	list_add_tail(&item->list, &dlm->work_list);
	spin_unlock(&dlm->work_lock);

	queue_work(dlm->dlm_worker, &dlm->dispatched_work);
	return 0;

2347 2348 2349 2350
done:
	if (res)
		dlm_lockres_put(res);
	dlm_put(dlm);
2351

2352 2353 2354
	return ret;
}

2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369
static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data)
{
	struct dlm_ctxt *dlm;
	struct dlm_lock_resource *res;
	u8 node;
	u8 cleared = 0;

	dlm = item->dlm;
	res = item->u.dl.deref_res;
	node = item->u.dl.deref_node;

	spin_lock(&res->spinlock);
	BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
	if (test_bit(node, res->refmap)) {
		__dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);
2370
		dlm_lockres_clear_refmap_bit(dlm, res, node);
2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382
		cleared = 1;
	}
	spin_unlock(&res->spinlock);

	if (cleared) {
		mlog(0, "%s:%.*s node %u ref dropped in dispatch\n",
		     dlm->name, res->lockname.len, res->lockname.name, node);
		dlm_lockres_calc_usage(dlm, res);
	} else {
		mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
		     "but it is already dropped!\n", dlm->name,
		     res->lockname.len, res->lockname.name, node);
2383
		dlm_print_one_lock_resource(res);
2384 2385 2386 2387 2388
	}

	dlm_lockres_put(res);
}

2389 2390 2391 2392 2393 2394
/*
 * A migrateable resource is one that is :
 * 1. locally mastered, and,
 * 2. zero local locks, and,
 * 3. one or more non-local locks, or, one or more references
 * Returns 1 if yes, 0 if not.
2395 2396
 */
static int dlm_is_lockres_migrateable(struct dlm_ctxt *dlm,
2397
				      struct dlm_lock_resource *res)
2398
{
2399 2400
	enum dlm_lockres_list idx;
	int nonlocal = 0, node_ref;
2401
	struct list_head *queue;
2402
	struct dlm_lock *lock;
2403
	u64 cookie;
2404 2405 2406

	assert_spin_locked(&res->spinlock);

2407 2408 2409 2410
	/* delay migration when the lockres is in MIGRATING state */
	if (res->state & DLM_LOCK_RES_MIGRATING)
		return 0;

2411 2412 2413 2414
	/* delay migration when the lockres is in RECOCERING state */
	if (res->state & DLM_LOCK_RES_RECOVERING)
		return 0;

2415 2416
	if (res->owner != dlm->node_num)
		return 0;
2417

2418 2419
        for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
		queue = dlm_list_idx_to_ptr(res, idx);
2420
		list_for_each_entry(lock, queue, list) {
2421 2422 2423
			if (lock->ml.node != dlm->node_num) {
				nonlocal++;
				continue;
2424
			}
2425 2426 2427 2428 2429 2430 2431 2432
			cookie = be64_to_cpu(lock->ml.cookie);
			mlog(0, "%s: Not migrateable res %.*s, lock %u:%llu on "
			     "%s list\n", dlm->name, res->lockname.len,
			     res->lockname.name,
			     dlm_get_lock_cookie_node(cookie),
			     dlm_get_lock_cookie_seq(cookie),
			     dlm_list_in_text(idx));
			return 0;
2433 2434 2435
		}
	}

2436 2437 2438 2439 2440
	if (!nonlocal) {
		node_ref = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
		if (node_ref >= O2NM_MAX_NODES)
			return 0;
	}
2441

2442 2443
	mlog(0, "%s: res %.*s, Migrateable\n", dlm->name, res->lockname.len,
	     res->lockname.name);
2444

2445
	return 1;
2446
}
2447 2448 2449 2450 2451 2452

/*
 * DLM_MIGRATE_LOCKRES
 */


2453
static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
2454
			       struct dlm_lock_resource *res, u8 target)
2455 2456 2457 2458
{
	struct dlm_master_list_entry *mle = NULL;
	struct dlm_master_list_entry *oldmle = NULL;
 	struct dlm_migratable_lockres *mres = NULL;
2459
	int ret = 0;
2460 2461 2462
	const char *name;
	unsigned int namelen;
	int mle_added = 0;
2463
	int wake = 0;
2464 2465 2466 2467

	if (!dlm_grab(dlm))
		return -EINVAL;

2468 2469
	BUG_ON(target == O2NM_MAX_NODES);

2470 2471 2472
	name = res->lockname.name;
	namelen = res->lockname.len;

2473 2474
	mlog(0, "%s: Migrating %.*s to node %u\n", dlm->name, namelen, name,
	     target);
2475

2476
	/* preallocate up front. if this fails, abort */
2477
	ret = -ENOMEM;
2478
	mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS);
2479 2480 2481 2482 2483
	if (!mres) {
		mlog_errno(ret);
		goto leave;
	}

2484
	mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
2485 2486 2487 2488 2489 2490 2491 2492 2493 2494
	if (!mle) {
		mlog_errno(ret);
		goto leave;
	}
	ret = 0;

	/*
	 * clear any existing master requests and
	 * add the migration mle to the list
	 */
2495
	spin_lock(&dlm->spinlock);
2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517
	spin_lock(&dlm->master_lock);
	ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
				    namelen, target, dlm->node_num);
	spin_unlock(&dlm->master_lock);
	spin_unlock(&dlm->spinlock);

	if (ret == -EEXIST) {
		mlog(0, "another process is already migrating it\n");
		goto fail;
	}
	mle_added = 1;

	/*
	 * set the MIGRATING flag and flush asts
	 * if we fail after this we need to re-dirty the lockres
	 */
	if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
		mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
		     "the target went down.\n", res->lockname.len,
		     res->lockname.name, target);
		spin_lock(&res->spinlock);
		res->state &= ~DLM_LOCK_RES_MIGRATING;
2518
		wake = 1;
2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535
		spin_unlock(&res->spinlock);
		ret = -EINVAL;
	}

fail:
	if (oldmle) {
		/* master is known, detach if not already detached */
		dlm_mle_detach_hb_events(dlm, oldmle);
		dlm_put_mle(oldmle);
	}

	if (ret < 0) {
		if (mle_added) {
			dlm_mle_detach_hb_events(dlm, mle);
			dlm_put_mle(mle);
		} else if (mle) {
			kmem_cache_free(dlm_mle_cache, mle);
2536
			mle = NULL;
2537 2538 2539 2540 2541 2542 2543 2544 2545 2546
		}
		goto leave;
	}

	/*
	 * at this point, we have a migration target, an mle
	 * in the master list, and the MIGRATING flag set on
	 * the lockres
	 */

2547 2548 2549
	/* now that remote nodes are spinning on the MIGRATING flag,
	 * ensure that all assert_master work is flushed. */
	flush_workqueue(dlm->dlm_worker);
2550 2551 2552 2553 2554 2555 2556 2557

	/* get an extra reference on the mle.
	 * otherwise the assert_master from the new
	 * master will destroy this.
	 * also, make sure that all callers of dlm_get_mle
	 * take both dlm->spinlock and dlm->master_lock */
	spin_lock(&dlm->spinlock);
	spin_lock(&dlm->master_lock);
K
Kurt Hackel 已提交
2558
	dlm_get_mle_inuse(mle);
2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574
	spin_unlock(&dlm->master_lock);
	spin_unlock(&dlm->spinlock);

	/* notify new node and send all lock state */
	/* call send_one_lockres with migration flag.
	 * this serves as notice to the target node that a
	 * migration is starting. */
	ret = dlm_send_one_lockres(dlm, res, mres, target,
				   DLM_MRES_MIGRATION);

	if (ret < 0) {
		mlog(0, "migration to node %u failed with %d\n",
		     target, ret);
		/* migration failed, detach and clean up mle */
		dlm_mle_detach_hb_events(dlm, mle);
		dlm_put_mle(mle);
K
Kurt Hackel 已提交
2575 2576 2577
		dlm_put_mle_inuse(mle);
		spin_lock(&res->spinlock);
		res->state &= ~DLM_LOCK_RES_MIGRATING;
2578
		wake = 1;
K
Kurt Hackel 已提交
2579
		spin_unlock(&res->spinlock);
2580 2581 2582
		if (dlm_is_host_down(ret))
			dlm_wait_for_node_death(dlm, target,
						DLM_NODE_DEATH_WAIT_MAX);
2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593
		goto leave;
	}

	/* at this point, the target sends a message to all nodes,
	 * (using dlm_do_migrate_request).  this node is skipped since
	 * we had to put an mle in the list to begin the process.  this
	 * node now waits for target to do an assert master.  this node
	 * will be the last one notified, ensuring that the migration
	 * is complete everywhere.  if the target dies while this is
	 * going on, some nodes could potentially see the target as the
	 * master, so it is important that my recovery finds the migration
2594
	 * mle and sets the master to UNKNOWN. */
2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607


	/* wait for new node to assert master */
	while (1) {
		ret = wait_event_interruptible_timeout(mle->wq,
					(atomic_read(&mle->woken) == 1),
					msecs_to_jiffies(5000));

		if (ret >= 0) {
		       	if (atomic_read(&mle->woken) == 1 ||
			    res->owner == target)
				break;

2608 2609
			mlog(0, "%s:%.*s: timed out during migration\n",
			     dlm->name, res->lockname.len, res->lockname.name);
2610
			/* avoid hang during shutdown when migrating lockres
K
Kurt Hackel 已提交
2611 2612
			 * to a node which also goes down */
			if (dlm_is_node_dead(dlm, target)) {
K
Kurt Hackel 已提交
2613 2614
				mlog(0, "%s:%.*s: expected migration "
				     "target %u is no longer up, restarting\n",
K
Kurt Hackel 已提交
2615 2616
				     dlm->name, res->lockname.len,
				     res->lockname.name, target);
2617 2618 2619 2620 2621 2622 2623
				ret = -EINVAL;
				/* migration failed, detach and clean up mle */
				dlm_mle_detach_hb_events(dlm, mle);
				dlm_put_mle(mle);
				dlm_put_mle_inuse(mle);
				spin_lock(&res->spinlock);
				res->state &= ~DLM_LOCK_RES_MIGRATING;
2624
				wake = 1;
2625 2626
				spin_unlock(&res->spinlock);
				goto leave;
K
Kurt Hackel 已提交
2627
			}
2628 2629 2630
		} else
			mlog(0, "%s:%.*s: caught signal during migration\n",
			     dlm->name, res->lockname.len, res->lockname.name);
2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642
	}

	/* all done, set the owner, clear the flag */
	spin_lock(&res->spinlock);
	dlm_set_lockres_owner(dlm, res, target);
	res->state &= ~DLM_LOCK_RES_MIGRATING;
	dlm_remove_nonlocal_locks(dlm, res);
	spin_unlock(&res->spinlock);
	wake_up(&res->wq);

	/* master is known, detach if not already detached */
	dlm_mle_detach_hb_events(dlm, mle);
K
Kurt Hackel 已提交
2643
	dlm_put_mle_inuse(mle);
2644 2645 2646 2647 2648 2649 2650 2651 2652
	ret = 0;

	dlm_lockres_calc_usage(dlm, res);

leave:
	/* re-dirty the lockres if we failed */
	if (ret < 0)
		dlm_kick_thread(dlm, res);

2653 2654 2655 2656 2657
	/* wake up waiters if the MIGRATING flag got set
	 * but migration failed */
	if (wake)
		wake_up(&res->wq);

2658 2659 2660 2661 2662
	if (mres)
		free_page((unsigned long)mres);

	dlm_put(dlm);

2663 2664
	mlog(0, "%s: Migrating %.*s to %u, returns %d\n", dlm->name, namelen,
	     name, target, ret);
2665 2666 2667
	return ret;
}

2668 2669
#define DLM_MIGRATION_RETRY_MS  100

2670 2671
/*
 * Should be called only after beginning the domain leave process.
2672 2673 2674 2675 2676 2677
 * There should not be any remaining locks on nonlocal lock resources,
 * and there should be no local locks left on locally mastered resources.
 *
 * Called with the dlm spinlock held, may drop it to do migration, but
 * will re-acquire before exit.
 *
2678 2679
 * Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped
 */
2680 2681
int dlm_empty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
{
2682
	int ret;
2683
	int lock_dropped = 0;
2684
	u8 target = O2NM_MAX_NODES;
2685

2686
	assert_spin_locked(&dlm->spinlock);
2687

2688
	spin_lock(&res->spinlock);
2689 2690
	if (dlm_is_lockres_migrateable(dlm, res))
		target = dlm_pick_migration_target(dlm, res);
2691
	spin_unlock(&res->spinlock);
2692 2693

	if (target == O2NM_MAX_NODES)
2694
		goto leave;
2695 2696 2697 2698

	/* Wheee! Migrate lockres here! Will sleep so drop spinlock. */
	spin_unlock(&dlm->spinlock);
	lock_dropped = 1;
2699 2700 2701 2702 2703
	ret = dlm_migrate_lockres(dlm, res, target);
	if (ret)
		mlog(0, "%s: res %.*s, Migrate to node %u failed with %d\n",
		     dlm->name, res->lockname.len, res->lockname.name,
		     target, ret);
2704 2705 2706 2707 2708
	spin_lock(&dlm->spinlock);
leave:
	return lock_dropped;
}

2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728
int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
{
	int ret;
	spin_lock(&dlm->ast_lock);
	spin_lock(&lock->spinlock);
	ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
	spin_unlock(&lock->spinlock);
	spin_unlock(&dlm->ast_lock);
	return ret;
}

static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
				     struct dlm_lock_resource *res,
				     u8 mig_target)
{
	int can_proceed;
	spin_lock(&res->spinlock);
	can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
	spin_unlock(&res->spinlock);

2729
	/* target has died, so make the caller break out of the
2730 2731 2732 2733 2734 2735 2736 2737
	 * wait_event, but caller must recheck the domain_map */
	spin_lock(&dlm->spinlock);
	if (!test_bit(mig_target, dlm->domain_map))
		can_proceed = 1;
	spin_unlock(&dlm->spinlock);
	return can_proceed;
}

2738 2739
static int dlm_lockres_is_dirty(struct dlm_ctxt *dlm,
				struct dlm_lock_resource *res)
2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767
{
	int ret;
	spin_lock(&res->spinlock);
	ret = !!(res->state & DLM_LOCK_RES_DIRTY);
	spin_unlock(&res->spinlock);
	return ret;
}


static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
				       struct dlm_lock_resource *res,
				       u8 target)
{
	int ret = 0;

	mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
	       res->lockname.len, res->lockname.name, dlm->node_num,
	       target);
	/* need to set MIGRATING flag on lockres.  this is done by
	 * ensuring that all asts have been flushed for this lockres. */
	spin_lock(&res->spinlock);
	BUG_ON(res->migration_pending);
	res->migration_pending = 1;
	/* strategy is to reserve an extra ast then release
	 * it below, letting the release do all of the work */
	__dlm_lockres_reserve_ast(res);
	spin_unlock(&res->spinlock);

2768
	/* now flush all the pending asts */
2769
	dlm_kick_thread(dlm, res);
2770 2771 2772 2773 2774 2775 2776
	/* before waiting on DIRTY, block processes which may
	 * try to dirty the lockres before MIGRATING is set */
	spin_lock(&res->spinlock);
	BUG_ON(res->state & DLM_LOCK_RES_BLOCK_DIRTY);
	res->state |= DLM_LOCK_RES_BLOCK_DIRTY;
	spin_unlock(&res->spinlock);
	/* now wait on any pending asts and the DIRTY state */
2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802
	wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
	dlm_lockres_release_ast(dlm, res);

	mlog(0, "about to wait on migration_wq, dirty=%s\n",
	       res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
	/* if the extra ref we just put was the final one, this
	 * will pass thru immediately.  otherwise, we need to wait
	 * for the last ast to finish. */
again:
	ret = wait_event_interruptible_timeout(dlm->migration_wq,
		   dlm_migration_can_proceed(dlm, res, target),
		   msecs_to_jiffies(1000));
	if (ret < 0) {
		mlog(0, "woken again: migrating? %s, dead? %s\n",
		       res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
		       test_bit(target, dlm->domain_map) ? "no":"yes");
	} else {
		mlog(0, "all is well: migrating? %s, dead? %s\n",
		       res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
		       test_bit(target, dlm->domain_map) ? "no":"yes");
	}
	if (!dlm_migration_can_proceed(dlm, res, target)) {
		mlog(0, "trying again...\n");
		goto again;
	}

2803
	ret = 0;
2804 2805 2806 2807 2808 2809 2810 2811 2812
	/* did the target go down or die? */
	spin_lock(&dlm->spinlock);
	if (!test_bit(target, dlm->domain_map)) {
		mlog(ML_ERROR, "aha. migration target %u just went down\n",
		     target);
		ret = -EHOSTDOWN;
	}
	spin_unlock(&dlm->spinlock);

2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824
	/*
	 * if target is down, we need to clear DLM_LOCK_RES_BLOCK_DIRTY for
	 * another try; otherwise, we are sure the MIGRATING state is there,
	 * drop the unneded state which blocked threads trying to DIRTY
	 */
	spin_lock(&res->spinlock);
	BUG_ON(!(res->state & DLM_LOCK_RES_BLOCK_DIRTY));
	res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY;
	if (!ret)
		BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING));
	spin_unlock(&res->spinlock);

2825 2826 2827
	/*
	 * at this point:
	 *
2828
	 *   o the DLM_LOCK_RES_MIGRATING flag is set if target not down
2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842
	 *   o there are no pending asts on this lockres
	 *   o all processes trying to reserve an ast on this
	 *     lockres must wait for the MIGRATING flag to clear
	 */
	return ret;
}

/* last step in the migration process.
 * original master calls this to free all of the dlm_lock
 * structures that used to be for other nodes. */
static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
				      struct dlm_lock_resource *res)
{
	struct list_head *queue = &res->granted;
2843
	int i, bit;
2844
	struct dlm_lock *lock, *next;
2845 2846 2847 2848 2849 2850

	assert_spin_locked(&res->spinlock);

	BUG_ON(res->owner == dlm->node_num);

	for (i=0; i<3; i++) {
2851
		list_for_each_entry_safe(lock, next, queue, list) {
2852 2853 2854 2855 2856 2857 2858 2859
			if (lock->ml.node != dlm->node_num) {
				mlog(0, "putting lock for node %u\n",
				     lock->ml.node);
				/* be extra careful */
				BUG_ON(!list_empty(&lock->ast_list));
				BUG_ON(!list_empty(&lock->bast_list));
				BUG_ON(lock->ast_pending);
				BUG_ON(lock->bast_pending);
2860 2861
				dlm_lockres_clear_refmap_bit(dlm, res,
							     lock->ml.node);
2862 2863
				list_del_init(&lock->list);
				dlm_lock_put(lock);
2864 2865 2866
				/* In a normal unlock, we would have added a
				 * DLM_UNLOCK_FREE_LOCK action. Force it. */
				dlm_lock_put(lock);
2867 2868 2869 2870
			}
		}
		queue++;
	}
2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881
	bit = 0;
	while (1) {
		bit = find_next_bit(res->refmap, O2NM_MAX_NODES, bit);
		if (bit >= O2NM_MAX_NODES)
			break;
		/* do not clear the local node reference, if there is a
		 * process holding this, let it drop the ref itself */
		if (bit != dlm->node_num) {
			mlog(0, "%s:%.*s: node %u had a ref to this "
			     "migrating lockres, clearing\n", dlm->name,
			     res->lockname.len, res->lockname.name, bit);
2882
			dlm_lockres_clear_refmap_bit(dlm, res, bit);
2883 2884 2885
		}
		bit++;
	}
2886 2887
}

2888 2889 2890 2891 2892
/*
 * Pick a node to migrate the lock resource to. This function selects a
 * potential target based first on the locks and then on refmap. It skips
 * nodes that are in the process of exiting the domain.
 */
2893 2894 2895
static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
				    struct dlm_lock_resource *res)
{
2896
	enum dlm_lockres_list idx;
2897 2898
	struct list_head *queue = &res->granted;
	struct dlm_lock *lock;
2899 2900
	int noderef;
	u8 nodenum = O2NM_MAX_NODES;
2901 2902

	assert_spin_locked(&dlm->spinlock);
2903
	assert_spin_locked(&res->spinlock);
2904

2905 2906 2907
	/* Go through all the locks */
	for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
		queue = dlm_list_idx_to_ptr(res, idx);
2908
		list_for_each_entry(lock, queue, list) {
2909 2910 2911 2912 2913 2914
			if (lock->ml.node == dlm->node_num)
				continue;
			if (test_bit(lock->ml.node, dlm->exit_domain_map))
				continue;
			nodenum = lock->ml.node;
			goto bail;
2915 2916
		}
	}
2917

2918 2919
	/* Go thru the refmap */
	noderef = -1;
2920
	while (1) {
2921 2922 2923
		noderef = find_next_bit(res->refmap, O2NM_MAX_NODES,
					noderef + 1);
		if (noderef >= O2NM_MAX_NODES)
2924
			break;
2925 2926 2927 2928 2929 2930
		if (noderef == dlm->node_num)
			continue;
		if (test_bit(noderef, dlm->exit_domain_map))
			continue;
		nodenum = noderef;
		goto bail;
2931 2932
	}

2933 2934
bail:
	return nodenum;
2935 2936 2937 2938 2939 2940 2941 2942 2943 2944
}

/* this is called by the new master once all lockres
 * data has been received */
static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
				  struct dlm_lock_resource *res,
				  u8 master, u8 new_master,
				  struct dlm_node_iter *iter)
{
	struct dlm_migrate_request migrate;
2945
	int ret, skip, status = 0;
2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961
	int nodenum;

	memset(&migrate, 0, sizeof(migrate));
	migrate.namelen = res->lockname.len;
	memcpy(migrate.name, res->lockname.name, migrate.namelen);
	migrate.new_master = new_master;
	migrate.master = master;

	ret = 0;

	/* send message to all nodes, except the master and myself */
	while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
		if (nodenum == master ||
		    nodenum == new_master)
			continue;

2962 2963 2964 2965 2966 2967 2968 2969 2970
		/* We could race exit domain. If exited, skip. */
		spin_lock(&dlm->spinlock);
		skip = (!test_bit(nodenum, dlm->domain_map));
		spin_unlock(&dlm->spinlock);
		if (skip) {
			clear_bit(nodenum, iter->node_map);
			continue;
		}

2971 2972 2973
		ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
					 &migrate, sizeof(migrate), nodenum,
					 &status);
2974
		if (ret < 0) {
2975 2976 2977
			mlog(ML_ERROR, "%s: res %.*s, Error %d send "
			     "MIGRATE_REQUEST to node %u\n", dlm->name,
			     migrate.namelen, migrate.name, ret, nodenum);
2978 2979 2980 2981 2982 2983 2984
			if (!dlm_is_host_down(ret)) {
				mlog(ML_ERROR, "unhandled error=%d!\n", ret);
				BUG();
			}
			clear_bit(nodenum, iter->node_map);
			ret = 0;
		} else if (status < 0) {
2985 2986 2987
			mlog(0, "migrate request (node %u) returned %d!\n",
			     nodenum, status);
			ret = status;
2988 2989 2990 2991 2992 2993 2994 2995
		} else if (status == DLM_MIGRATE_RESPONSE_MASTERY_REF) {
			/* during the migration request we short-circuited
			 * the mastery of the lockres.  make sure we have
			 * a mastery ref for nodenum */
			mlog(0, "%s:%.*s: need ref for node %u\n",
			     dlm->name, res->lockname.len, res->lockname.name,
			     nodenum);
			spin_lock(&res->spinlock);
2996
			dlm_lockres_set_refmap_bit(dlm, res, nodenum);
2997
			spin_unlock(&res->spinlock);
2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015
		}
	}

	if (ret < 0)
		mlog_errno(ret);

	mlog(0, "returning ret=%d\n", ret);
	return ret;
}


/* if there is an existing mle for this lockres, we now know who the master is.
 * (the one who sent us *this* message) we can clear it up right away.
 * since the process that put the mle on the list still has a reference to it,
 * we can unhash it now, set the master and wake the process.  as a result,
 * we will have no mle in the list to start with.  now we can add an mle for
 * the migration and this should be the only one found for those scanning the
 * list.  */
3016 3017
int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data,
				void **ret_data)
3018 3019 3020 3021 3022 3023
{
	struct dlm_ctxt *dlm = data;
	struct dlm_lock_resource *res = NULL;
	struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
	struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
	const char *name;
3024
	unsigned int namelen, hash;
3025 3026 3027 3028 3029 3030 3031
	int ret = 0;

	if (!dlm_grab(dlm))
		return -EINVAL;

	name = migrate->name;
	namelen = migrate->namelen;
3032
	hash = dlm_lockid_hash(name, namelen);
3033 3034

	/* preallocate.. if this fails, abort */
3035
	mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
3036 3037 3038 3039 3040 3041 3042 3043

	if (!mle) {
		ret = -ENOMEM;
		goto leave;
	}

	/* check for pre-existing lock */
	spin_lock(&dlm->spinlock);
3044
	res = __dlm_lookup_lockres(dlm, name, namelen, hash);
3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061
	if (res) {
		spin_lock(&res->spinlock);
		if (res->state & DLM_LOCK_RES_RECOVERING) {
			/* if all is working ok, this can only mean that we got
		 	* a migrate request from a node that we now see as
		 	* dead.  what can we do here?  drop it to the floor? */
			spin_unlock(&res->spinlock);
			mlog(ML_ERROR, "Got a migrate request, but the "
			     "lockres is marked as recovering!");
			kmem_cache_free(dlm_mle_cache, mle);
			ret = -EINVAL; /* need a better solution */
			goto unlock;
		}
		res->state |= DLM_LOCK_RES_MIGRATING;
		spin_unlock(&res->spinlock);
	}

W
Wengang Wang 已提交
3062
	spin_lock(&dlm->master_lock);
3063 3064 3065 3066 3067 3068 3069
	/* ignore status.  only nonzero status would BUG. */
	ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
				    name, namelen,
				    migrate->new_master,
				    migrate->master);

	spin_unlock(&dlm->master_lock);
W
Wengang Wang 已提交
3070
unlock:
3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135
	spin_unlock(&dlm->spinlock);

	if (oldmle) {
		/* master is known, detach if not already detached */
		dlm_mle_detach_hb_events(dlm, oldmle);
		dlm_put_mle(oldmle);
	}

	if (res)
		dlm_lockres_put(res);
leave:
	dlm_put(dlm);
	return ret;
}

/* must be holding dlm->spinlock and dlm->master_lock
 * when adding a migration mle, we can clear any other mles
 * in the master list because we know with certainty that
 * the master is "master".  so we remove any old mle from
 * the list after setting it's master field, and then add
 * the new migration mle.  this way we can hold with the rule
 * of having only one mle for a given lock name at all times. */
static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
				 struct dlm_lock_resource *res,
				 struct dlm_master_list_entry *mle,
				 struct dlm_master_list_entry **oldmle,
				 const char *name, unsigned int namelen,
				 u8 new_master, u8 master)
{
	int found;
	int ret = 0;

	*oldmle = NULL;

	assert_spin_locked(&dlm->spinlock);
	assert_spin_locked(&dlm->master_lock);

	/* caller is responsible for any ref taken here on oldmle */
	found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
	if (found) {
		struct dlm_master_list_entry *tmp = *oldmle;
		spin_lock(&tmp->spinlock);
		if (tmp->type == DLM_MLE_MIGRATION) {
			if (master == dlm->node_num) {
				/* ah another process raced me to it */
				mlog(0, "tried to migrate %.*s, but some "
				     "process beat me to it\n",
				     namelen, name);
				ret = -EEXIST;
			} else {
				/* bad.  2 NODES are trying to migrate! */
				mlog(ML_ERROR, "migration error  mle: "
				     "master=%u new_master=%u // request: "
				     "master=%u new_master=%u // "
				     "lockres=%.*s\n",
				     tmp->master, tmp->new_master,
				     master, new_master,
				     namelen, name);
				BUG();
			}
		} else {
			/* this is essentially what assert_master does */
			tmp->master = master;
			atomic_set(&tmp->woken, 1);
			wake_up(&tmp->wq);
3136 3137
			/* remove it so that only one mle will be found */
			__dlm_unlink_mle(dlm, tmp);
3138
			__dlm_mle_detach_hb_events(dlm, tmp);
3139 3140 3141 3142 3143 3144 3145 3146 3147
			if (tmp->type == DLM_MLE_MASTER) {
				ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
				mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
						"telling master to get ref "
						"for cleared out mle during "
						"migration\n", dlm->name,
						namelen, name, master,
						new_master);
			}
3148 3149 3150 3151 3152 3153 3154
		}
		spin_unlock(&tmp->spinlock);
	}

	/* now add a migration mle to the tail of the list */
	dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
	mle->new_master = new_master;
3155 3156
	/* the new master will be sending an assert master for this.
	 * at that point we will get the refmap reference */
3157 3158 3159
	mle->master = master;
	/* do this for consistency with other mle types */
	set_bit(new_master, mle->maybe_map);
3160
	__dlm_insert_mle(dlm, mle);
3161 3162 3163 3164

	return ret;
}

3165 3166 3167 3168 3169 3170 3171 3172 3173
/*
 * Sets the owner of the lockres, associated to the mle, to UNKNOWN
 */
static struct dlm_lock_resource *dlm_reset_mleres_owner(struct dlm_ctxt *dlm,
					struct dlm_master_list_entry *mle)
{
	struct dlm_lock_resource *res;

	/* Find the lockres associated to the mle and set its owner to UNK */
3174 3175
	res = __dlm_lookup_lockres(dlm, mle->mname, mle->mnamelen,
				   mle->mnamehash);
3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238
	if (res) {
		spin_unlock(&dlm->master_lock);

		/* move lockres onto recovery list */
		spin_lock(&res->spinlock);
		dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
		dlm_move_lockres_to_recovery_list(dlm, res);
		spin_unlock(&res->spinlock);
		dlm_lockres_put(res);

		/* about to get rid of mle, detach from heartbeat */
		__dlm_mle_detach_hb_events(dlm, mle);

		/* dump the mle */
		spin_lock(&dlm->master_lock);
		__dlm_put_mle(mle);
		spin_unlock(&dlm->master_lock);
	}

	return res;
}

static void dlm_clean_migration_mle(struct dlm_ctxt *dlm,
				    struct dlm_master_list_entry *mle)
{
	__dlm_mle_detach_hb_events(dlm, mle);

	spin_lock(&mle->spinlock);
	__dlm_unlink_mle(dlm, mle);
	atomic_set(&mle->woken, 1);
	spin_unlock(&mle->spinlock);

	wake_up(&mle->wq);
}

static void dlm_clean_block_mle(struct dlm_ctxt *dlm,
				struct dlm_master_list_entry *mle, u8 dead_node)
{
	int bit;

	BUG_ON(mle->type != DLM_MLE_BLOCK);

	spin_lock(&mle->spinlock);
	bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
	if (bit != dead_node) {
		mlog(0, "mle found, but dead node %u would not have been "
		     "master\n", dead_node);
		spin_unlock(&mle->spinlock);
	} else {
		/* Must drop the refcount by one since the assert_master will
		 * never arrive. This may result in the mle being unlinked and
		 * freed, but there may still be a process waiting in the
		 * dlmlock path which is fine. */
		mlog(0, "node %u was expected master\n", dead_node);
		atomic_set(&mle->woken, 1);
		spin_unlock(&mle->spinlock);
		wake_up(&mle->wq);

		/* Do not need events any longer, so detach from heartbeat */
		__dlm_mle_detach_hb_events(dlm, mle);
		__dlm_put_mle(mle);
	}
}
3239 3240 3241

void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
{
3242
	struct dlm_master_list_entry *mle;
3243
	struct dlm_lock_resource *res;
3244
	struct hlist_head *bucket;
3245
	struct hlist_node *tmp;
3246
	unsigned int i;
3247

T
Tao Ma 已提交
3248
	mlog(0, "dlm=%s, dead node=%u\n", dlm->name, dead_node);
3249 3250 3251 3252 3253
top:
	assert_spin_locked(&dlm->spinlock);

	/* clean the master list */
	spin_lock(&dlm->master_lock);
3254 3255
	for (i = 0; i < DLM_HASH_BUCKETS; i++) {
		bucket = dlm_master_hash(dlm, i);
3256
		hlist_for_each_entry_safe(mle, tmp, bucket, master_hash_node) {
3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273
			BUG_ON(mle->type != DLM_MLE_BLOCK &&
			       mle->type != DLM_MLE_MASTER &&
			       mle->type != DLM_MLE_MIGRATION);

			/* MASTER mles are initiated locally. The waiting
			 * process will notice the node map change shortly.
			 * Let that happen as normal. */
			if (mle->type == DLM_MLE_MASTER)
				continue;

			/* BLOCK mles are initiated by other nodes. Need to
			 * clean up if the dead node would have been the
			 * master. */
			if (mle->type == DLM_MLE_BLOCK) {
				dlm_clean_block_mle(dlm, mle, dead_node);
				continue;
			}
3274

3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309
			/* Everything else is a MIGRATION mle */

			/* The rule for MIGRATION mles is that the master
			 * becomes UNKNOWN if *either* the original or the new
			 * master dies. All UNKNOWN lockres' are sent to
			 * whichever node becomes the recovery master. The new
			 * master is responsible for determining if there is
			 * still a master for this lockres, or if he needs to
			 * take over mastery. Either way, this node should
			 * expect another message to resolve this. */

			if (mle->master != dead_node &&
			    mle->new_master != dead_node)
				continue;

			/* If we have reached this point, this mle needs to be
			 * removed from the list and freed. */
			dlm_clean_migration_mle(dlm, mle);

			mlog(0, "%s: node %u died during migration from "
			     "%u to %u!\n", dlm->name, dead_node, mle->master,
			     mle->new_master);

			/* If we find a lockres associated with the mle, we've
			 * hit this rare case that messes up our lock ordering.
			 * If so, we need to drop the master lock so that we can
			 * take the lockres lock, meaning that we will have to
			 * restart from the head of list. */
			res = dlm_reset_mleres_owner(dlm, mle);
			if (res)
				/* restart */
				goto top;

			/* This may be the last reference */
			__dlm_put_mle(mle);
3310
		}
3311
	}
3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326
	spin_unlock(&dlm->master_lock);
}

int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
			 u8 old_master)
{
	struct dlm_node_iter iter;
	int ret = 0;

	spin_lock(&dlm->spinlock);
	dlm_node_iter_init(dlm->domain_map, &iter);
	clear_bit(old_master, iter.node_map);
	clear_bit(dlm->node_num, iter.node_map);
	spin_unlock(&dlm->spinlock);

3327 3328 3329 3330
	/* ownership of the lockres is changing.  account for the
	 * mastery reference here since old_master will briefly have
	 * a reference after the migration completes */
	spin_lock(&res->spinlock);
3331
	dlm_lockres_set_refmap_bit(dlm, res, old_master);
3332 3333
	spin_unlock(&res->spinlock);

3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345
	mlog(0, "now time to do a migrate request to other nodes\n");
	ret = dlm_do_migrate_request(dlm, res, old_master,
				     dlm->node_num, &iter);
	if (ret < 0) {
		mlog_errno(ret);
		goto leave;
	}

	mlog(0, "doing assert master of %.*s to all except the original node\n",
	     res->lockname.len, res->lockname.name);
	/* this call now finishes out the nodemap
	 * even if one or more nodes die */
3346
	ret = dlm_do_assert_master(dlm, res, iter.node_map,
3347 3348 3349 3350 3351 3352 3353 3354 3355 3356 3357
				   DLM_ASSERT_MASTER_FINISH_MIGRATION);
	if (ret < 0) {
		/* no longer need to retry.  all living nodes contacted. */
		mlog_errno(ret);
		ret = 0;
	}

	memset(iter.node_map, 0, sizeof(iter.node_map));
	set_bit(old_master, iter.node_map);
	mlog(0, "doing assert master of %.*s back to %u\n",
	     res->lockname.len, res->lockname.name, old_master);
3358
	ret = dlm_do_assert_master(dlm, res, iter.node_map,
3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430
				   DLM_ASSERT_MASTER_FINISH_MIGRATION);
	if (ret < 0) {
		mlog(0, "assert master to original master failed "
		     "with %d.\n", ret);
		/* the only nonzero status here would be because of
		 * a dead original node.  we're done. */
		ret = 0;
	}

	/* all done, set the owner, clear the flag */
	spin_lock(&res->spinlock);
	dlm_set_lockres_owner(dlm, res, dlm->node_num);
	res->state &= ~DLM_LOCK_RES_MIGRATING;
	spin_unlock(&res->spinlock);
	/* re-dirty it on the new master */
	dlm_kick_thread(dlm, res);
	wake_up(&res->wq);
leave:
	return ret;
}

/*
 * LOCKRES AST REFCOUNT
 * this is integral to migration
 */

/* for future intent to call an ast, reserve one ahead of time.
 * this should be called only after waiting on the lockres
 * with dlm_wait_on_lockres, and while still holding the
 * spinlock after the call. */
void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
{
	assert_spin_locked(&res->spinlock);
	if (res->state & DLM_LOCK_RES_MIGRATING) {
		__dlm_print_one_lock_resource(res);
	}
	BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);

	atomic_inc(&res->asts_reserved);
}

/*
 * used to drop the reserved ast, either because it went unused,
 * or because the ast/bast was actually called.
 *
 * also, if there is a pending migration on this lockres,
 * and this was the last pending ast on the lockres,
 * atomically set the MIGRATING flag before we drop the lock.
 * this is how we ensure that migration can proceed with no
 * asts in progress.  note that it is ok if the state of the
 * queues is such that a lock should be granted in the future
 * or that a bast should be fired, because the new master will
 * shuffle the lists on this lockres as soon as it is migrated.
 */
void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
			     struct dlm_lock_resource *res)
{
	if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
		return;

	if (!res->migration_pending) {
		spin_unlock(&res->spinlock);
		return;
	}

	BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
	res->migration_pending = 0;
	res->state |= DLM_LOCK_RES_MIGRATING;
	spin_unlock(&res->spinlock);
	wake_up(&res->wq);
	wake_up(&dlm->migration_wq);
}
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void dlm_force_free_mles(struct dlm_ctxt *dlm)
{
	int i;
	struct hlist_head *bucket;
	struct dlm_master_list_entry *mle;
3437
	struct hlist_node *tmp;
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	/*
	 * We notified all other nodes that we are exiting the domain and
	 * marked the dlm state to DLM_CTXT_LEAVING. If any mles are still
	 * around we force free them and wake any processes that are waiting
	 * on the mles
	 */
	spin_lock(&dlm->spinlock);
	spin_lock(&dlm->master_lock);

	BUG_ON(dlm->dlm_state != DLM_CTXT_LEAVING);
	BUG_ON((find_next_bit(dlm->domain_map, O2NM_MAX_NODES, 0) < O2NM_MAX_NODES));

	for (i = 0; i < DLM_HASH_BUCKETS; i++) {
		bucket = dlm_master_hash(dlm, i);
3453
		hlist_for_each_entry_safe(mle, tmp, bucket, master_hash_node) {
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			if (mle->type != DLM_MLE_BLOCK) {
				mlog(ML_ERROR, "bad mle: %p\n", mle);
				dlm_print_one_mle(mle);
			}
			atomic_set(&mle->woken, 1);
			wake_up(&mle->wq);

			__dlm_unlink_mle(dlm, mle);
			__dlm_mle_detach_hb_events(dlm, mle);
			__dlm_put_mle(mle);
		}
	}
	spin_unlock(&dlm->master_lock);
	spin_unlock(&dlm->spinlock);
}