/* -*- mode: c; c-basic-offset: 8; -*-
   * vim: noexpandtab sw=8 ts=8 sts=0:
   *
   * dlmthread.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/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/timer.h>
  #include <linux/kthread.h>

  #include <linux/delay.h>

  
  
  #include "cluster/heartbeat.h"
  #include "cluster/nodemanager.h"
  #include "cluster/tcp.h"
  
  #include "dlmapi.h"
  #include "dlmcommon.h"
  #include "dlmdomain.h"
  
  #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_THREAD)
  #include "cluster/masklog.h"

  static int dlm_thread(void *data);

  static void dlm_flush_asts(struct dlm_ctxt *dlm);
  
  #define dlm_lock_is_remote(dlm, lock)     ((lock)->ml.node != (dlm)->node_num)
  
  /* will exit holding res->spinlock, but may drop in function */
  /* waits until flags are cleared on res->state */
  void __dlm_wait_on_lockres_flags(struct dlm_lock_resource *res, int flags)
  {
  	DECLARE_WAITQUEUE(wait, current);
  
  	assert_spin_locked(&res->spinlock);
  
  	add_wait_queue(&res->wq, &wait);
  repeat:
  	set_current_state(TASK_UNINTERRUPTIBLE);
  	if (res->state & flags) {
  		spin_unlock(&res->spinlock);
  		schedule();
  		spin_lock(&res->spinlock);
  		goto repeat;
  	}
  	remove_wait_queue(&res->wq, &wait);

  	__set_current_state(TASK_RUNNING);

  }

  int __dlm_lockres_has_locks(struct dlm_lock_resource *res)

  {
  	if (list_empty(&res->granted) &&
  	    list_empty(&res->converting) &&

  	    list_empty(&res->blocked))
  		return 0;
  	return 1;
  }
  
  /* "unused": the lockres has no locks, is not on the dirty list,
   * has no inflight locks (in the gap between mastery and acquiring
   * the first lock), and has no bits in its refmap.
   * truly ready to be freed. */
  int __dlm_lockres_unused(struct dlm_lock_resource *res)
  {

  	int bit;

  	assert_spin_locked(&res->spinlock);

  	if (__dlm_lockres_has_locks(res))
  		return 0;

  	/* Locks are in the process of being created */
  	if (res->inflight_locks)
  		return 0;

  	if (!list_empty(&res->dirty) || res->state & DLM_LOCK_RES_DIRTY)
  		return 0;
  
  	if (res->state & DLM_LOCK_RES_RECOVERING)
  		return 0;

  	/* Another node has this resource with this node as the master */

  	bit = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
  	if (bit < O2NM_MAX_NODES)
  		return 0;

  	return 1;

  }
  
  
  /* Call whenever you may have added or deleted something from one of
   * the lockres queue's. This will figure out whether it belongs on the
   * unused list or not and does the appropriate thing. */
  void __dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
  			      struct dlm_lock_resource *res)
  {

  	assert_spin_locked(&dlm->spinlock);
  	assert_spin_locked(&res->spinlock);
  
  	if (__dlm_lockres_unused(res)){
  		if (list_empty(&res->purge)) {

  			mlog(0, "%s: Adding res %.*s to purge list
  ",
  			     dlm->name, res->lockname.len, res->lockname.name);

  
  			res->last_used = jiffies;

  			dlm_lockres_get(res);

  			list_add_tail(&res->purge, &dlm->purge_list);
  			dlm->purge_count++;
  		}
  	} else if (!list_empty(&res->purge)) {

  		mlog(0, "%s: Removing res %.*s from purge list
  ",
  		     dlm->name, res->lockname.len, res->lockname.name);

  
  		list_del_init(&res->purge);

  		dlm_lockres_put(res);

  		dlm->purge_count--;
  	}
  }
  
  void dlm_lockres_calc_usage(struct dlm_ctxt *dlm,
  			    struct dlm_lock_resource *res)
  {

  	spin_lock(&dlm->spinlock);
  	spin_lock(&res->spinlock);
  
  	__dlm_lockres_calc_usage(dlm, res);
  
  	spin_unlock(&res->spinlock);
  	spin_unlock(&dlm->spinlock);
  }

  static void dlm_purge_lockres(struct dlm_ctxt *dlm,

  			     struct dlm_lock_resource *res)

  {
  	int master;

  	int ret = 0;

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

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

  	mlog(0, "%s: Purging res %.*s, master %d
  ", dlm->name,
  	     res->lockname.len, res->lockname.name, master);

  
  	if (!master) {

  		res->state |= DLM_LOCK_RES_DROPPING_REF;

  		/* drop spinlock...  retake below */

  		spin_unlock(&res->spinlock);

  		spin_unlock(&dlm->spinlock);

  		spin_lock(&res->spinlock);
  		/* This ensures that clear refmap is sent after the set */

  		__dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);

  		spin_unlock(&res->spinlock);

  		/* clear our bit from the master's refmap, ignore errors */
  		ret = dlm_drop_lockres_ref(dlm, res);
  		if (ret < 0) {

  			if (!dlm_is_host_down(ret))
  				BUG();
  		}

  		spin_lock(&dlm->spinlock);

  		spin_lock(&res->spinlock);

  	}

  	if (!list_empty(&res->purge)) {

  		mlog(0, "%s: Removing res %.*s from purgelist, master %d
  ",
  		     dlm->name, res->lockname.len, res->lockname.name, master);

  		list_del_init(&res->purge);
  		dlm_lockres_put(res);

  		dlm->purge_count--;

  	}
  
  	if (!__dlm_lockres_unused(res)) {

  		mlog(ML_ERROR, "%s: res %.*s in use after deref
  ",

  		     dlm->name, res->lockname.len, res->lockname.name);
  		__dlm_print_one_lock_resource(res);
  		BUG();
  	}

  	__dlm_unhash_lockres(dlm, res);

  	/* lockres is not in the hash now.  drop the flag and wake up
  	 * any processes waiting in dlm_get_lock_resource. */
  	if (!master) {

  		res->state &= ~DLM_LOCK_RES_DROPPING_REF;
  		spin_unlock(&res->spinlock);
  		wake_up(&res->wq);

  	} else
  		spin_unlock(&res->spinlock);

  }

  static void dlm_run_purge_list(struct dlm_ctxt *dlm,
  			       int purge_now)
  {
  	unsigned int run_max, unused;
  	unsigned long purge_jiffies;
  	struct dlm_lock_resource *lockres;
  
  	spin_lock(&dlm->spinlock);
  	run_max = dlm->purge_count;
  
  	while(run_max && !list_empty(&dlm->purge_list)) {
  		run_max--;
  
  		lockres = list_entry(dlm->purge_list.next,
  				     struct dlm_lock_resource, purge);

  		spin_lock(&lockres->spinlock);

  
  		purge_jiffies = lockres->last_used +
  			msecs_to_jiffies(DLM_PURGE_INTERVAL_MS);
  
  		/* Make sure that we want to be processing this guy at
  		 * this time. */
  		if (!purge_now && time_after(purge_jiffies, jiffies)) {
  			/* Since resources are added to the purge list
  			 * in tail order, we can stop at the first
  			 * unpurgable resource -- anyone added after
  			 * him will have a greater last_used value */

  			spin_unlock(&lockres->spinlock);

  			break;
  		}

  		/* Status of the lockres *might* change so double
  		 * check. If the lockres is unused, holding the dlm
  		 * spinlock will prevent people from getting and more
  		 * refs on it. */
  		unused = __dlm_lockres_unused(lockres);
  		if (!unused ||
  		    (lockres->state & DLM_LOCK_RES_MIGRATING)) {

  			mlog(0, "%s: res %.*s is in use or being remastered, "
  			     "used %d, state %d
  ", dlm->name,
  			     lockres->lockname.len, lockres->lockname.name,
  			     !unused, lockres->state);

  			list_move_tail(&dlm->purge_list, &lockres->purge);
  			spin_unlock(&lockres->spinlock);
  			continue;
  		}

  		dlm_lockres_get(lockres);

  		dlm_purge_lockres(dlm, lockres);

  		dlm_lockres_put(lockres);

  
  		/* Avoid adding any scheduling latencies */
  		cond_resched_lock(&dlm->spinlock);
  	}
  
  	spin_unlock(&dlm->spinlock);
  }
  
  static void dlm_shuffle_lists(struct dlm_ctxt *dlm,
  			      struct dlm_lock_resource *res)
  {
  	struct dlm_lock *lock, *target;
  	struct list_head *iter;
  	struct list_head *head;
  	int can_grant = 1;

  	/*
  	 * Because this function is called with the lockres

  	 * spinlock, and because we know that it is not migrating/
  	 * recovering/in-progress, it is fine to reserve asts and

  	 * basts right before queueing them all throughout
  	 */

  	assert_spin_locked(&dlm->ast_lock);

  	assert_spin_locked(&res->spinlock);
  	BUG_ON((res->state & (DLM_LOCK_RES_MIGRATING|
  			      DLM_LOCK_RES_RECOVERING|
  			      DLM_LOCK_RES_IN_PROGRESS)));
  
  converting:
  	if (list_empty(&res->converting))
  		goto blocked;

  	mlog(0, "%s: res %.*s has locks on the convert queue
  ", dlm->name,
  	     res->lockname.len, res->lockname.name);

  
  	target = list_entry(res->converting.next, struct dlm_lock, list);
  	if (target->ml.convert_type == LKM_IVMODE) {

  		mlog(ML_ERROR, "%s: res %.*s converting lock to invalid mode
  ",
  		     dlm->name, res->lockname.len, res->lockname.name);

  		BUG();
  	}
  	head = &res->granted;
  	list_for_each(iter, head) {
  		lock = list_entry(iter, struct dlm_lock, list);
  		if (lock==target)
  			continue;
  		if (!dlm_lock_compatible(lock->ml.type,
  					 target->ml.convert_type)) {
  			can_grant = 0;
  			/* queue the BAST if not already */
  			if (lock->ml.highest_blocked == LKM_IVMODE) {
  				__dlm_lockres_reserve_ast(res);

  				__dlm_queue_bast(dlm, lock);

  			}
  			/* update the highest_blocked if needed */
  			if (lock->ml.highest_blocked < target->ml.convert_type)
  				lock->ml.highest_blocked =
  					target->ml.convert_type;
  		}
  	}
  	head = &res->converting;
  	list_for_each(iter, head) {
  		lock = list_entry(iter, struct dlm_lock, list);
  		if (lock==target)
  			continue;
  		if (!dlm_lock_compatible(lock->ml.type,
  					 target->ml.convert_type)) {
  			can_grant = 0;
  			if (lock->ml.highest_blocked == LKM_IVMODE) {
  				__dlm_lockres_reserve_ast(res);

  				__dlm_queue_bast(dlm, lock);

  			}
  			if (lock->ml.highest_blocked < target->ml.convert_type)
  				lock->ml.highest_blocked =
  					target->ml.convert_type;
  		}
  	}
  
  	/* we can convert the lock */
  	if (can_grant) {
  		spin_lock(&target->spinlock);
  		BUG_ON(target->ml.highest_blocked != LKM_IVMODE);

  		mlog(0, "%s: res %.*s, AST for Converting lock %u:%llu, type "
  		     "%d => %d, node %u
  ", dlm->name, res->lockname.len,
  		     res->lockname.name,
  		     dlm_get_lock_cookie_node(be64_to_cpu(target->ml.cookie)),
  		     dlm_get_lock_cookie_seq(be64_to_cpu(target->ml.cookie)),
  		     target->ml.type,

  		     target->ml.convert_type, target->ml.node);
  
  		target->ml.type = target->ml.convert_type;
  		target->ml.convert_type = LKM_IVMODE;

  		list_move_tail(&target->list, &res->granted);

  
  		BUG_ON(!target->lksb);
  		target->lksb->status = DLM_NORMAL;
  
  		spin_unlock(&target->spinlock);
  
  		__dlm_lockres_reserve_ast(res);

  		__dlm_queue_ast(dlm, target);

  		/* go back and check for more */
  		goto converting;
  	}
  
  blocked:
  	if (list_empty(&res->blocked))
  		goto leave;
  	target = list_entry(res->blocked.next, struct dlm_lock, list);
  
  	head = &res->granted;
  	list_for_each(iter, head) {
  		lock = list_entry(iter, struct dlm_lock, list);
  		if (lock==target)
  			continue;
  		if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) {
  			can_grant = 0;
  			if (lock->ml.highest_blocked == LKM_IVMODE) {
  				__dlm_lockres_reserve_ast(res);

  				__dlm_queue_bast(dlm, lock);

  			}
  			if (lock->ml.highest_blocked < target->ml.type)
  				lock->ml.highest_blocked = target->ml.type;
  		}
  	}
  
  	head = &res->converting;
  	list_for_each(iter, head) {
  		lock = list_entry(iter, struct dlm_lock, list);
  		if (lock==target)
  			continue;
  		if (!dlm_lock_compatible(lock->ml.type, target->ml.type)) {
  			can_grant = 0;
  			if (lock->ml.highest_blocked == LKM_IVMODE) {
  				__dlm_lockres_reserve_ast(res);

  				__dlm_queue_bast(dlm, lock);

  			}
  			if (lock->ml.highest_blocked < target->ml.type)
  				lock->ml.highest_blocked = target->ml.type;
  		}
  	}
  
  	/* we can grant the blocked lock (only
  	 * possible if converting list empty) */
  	if (can_grant) {
  		spin_lock(&target->spinlock);
  		BUG_ON(target->ml.highest_blocked != LKM_IVMODE);

  		mlog(0, "%s: res %.*s, AST for Blocked lock %u:%llu, type %d, "
  		     "node %u
  ", dlm->name, res->lockname.len,
  		     res->lockname.name,
  		     dlm_get_lock_cookie_node(be64_to_cpu(target->ml.cookie)),
  		     dlm_get_lock_cookie_seq(be64_to_cpu(target->ml.cookie)),

  		     target->ml.type, target->ml.node);

  		/* target->ml.type is already correct */

  		list_move_tail(&target->list, &res->granted);

  
  		BUG_ON(!target->lksb);
  		target->lksb->status = DLM_NORMAL;
  
  		spin_unlock(&target->spinlock);
  
  		__dlm_lockres_reserve_ast(res);

  		__dlm_queue_ast(dlm, target);

  		/* go back and check for more */
  		goto converting;
  	}
  
  leave:
  	return;
  }
  
  /* must have NO locks when calling this with res !=NULL * */
  void dlm_kick_thread(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
  {

  	if (res) {
  		spin_lock(&dlm->spinlock);
  		spin_lock(&res->spinlock);
  		__dlm_dirty_lockres(dlm, res);
  		spin_unlock(&res->spinlock);
  		spin_unlock(&dlm->spinlock);
  	}
  	wake_up(&dlm->dlm_thread_wq);
  }
  
  void __dlm_dirty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
  {

  	assert_spin_locked(&dlm->spinlock);
  	assert_spin_locked(&res->spinlock);
  
  	/* don't shuffle secondary queues */

  	if ((res->owner == dlm->node_num)) {
  		if (res->state & (DLM_LOCK_RES_MIGRATING |
  				  DLM_LOCK_RES_BLOCK_DIRTY))
  		    return;
  
  		if (list_empty(&res->dirty)) {
  			/* ref for dirty_list */
  			dlm_lockres_get(res);
  			list_add_tail(&res->dirty, &dlm->dirty_list);
  			res->state |= DLM_LOCK_RES_DIRTY;
  		}

  	}

  
  	mlog(0, "%s: res %.*s
  ", dlm->name, res->lockname.len,
  	     res->lockname.name);

  }
  
  
  /* Launch the NM thread for the mounted volume */
  int dlm_launch_thread(struct dlm_ctxt *dlm)
  {

  	mlog(0, "Starting dlm_thread...
  ");

  
  	dlm->dlm_thread_task = kthread_run(dlm_thread, dlm, "dlm_thread");
  	if (IS_ERR(dlm->dlm_thread_task)) {
  		mlog_errno(PTR_ERR(dlm->dlm_thread_task));
  		dlm->dlm_thread_task = NULL;
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  void dlm_complete_thread(struct dlm_ctxt *dlm)
  {
  	if (dlm->dlm_thread_task) {

  		mlog(ML_KTHREAD, "Waiting for dlm thread to exit
  ");

  		kthread_stop(dlm->dlm_thread_task);
  		dlm->dlm_thread_task = NULL;
  	}
  }
  
  static int dlm_dirty_list_empty(struct dlm_ctxt *dlm)
  {
  	int empty;
  
  	spin_lock(&dlm->spinlock);
  	empty = list_empty(&dlm->dirty_list);
  	spin_unlock(&dlm->spinlock);
  
  	return empty;
  }
  
  static void dlm_flush_asts(struct dlm_ctxt *dlm)
  {
  	int ret;
  	struct dlm_lock *lock;
  	struct dlm_lock_resource *res;
  	u8 hi;
  
  	spin_lock(&dlm->ast_lock);
  	while (!list_empty(&dlm->pending_asts)) {
  		lock = list_entry(dlm->pending_asts.next,
  				  struct dlm_lock, ast_list);
  		/* get an extra ref on lock */
  		dlm_lock_get(lock);
  		res = lock->lockres;

  		mlog(0, "%s: res %.*s, Flush AST for lock %u:%llu, type %d, "
  		     "node %u
  ", dlm->name, res->lockname.len,
  		     res->lockname.name,
  		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
  		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
  		     lock->ml.type, lock->ml.node);

  
  		BUG_ON(!lock->ast_pending);
  
  		/* remove from list (including ref) */
  		list_del_init(&lock->ast_list);
  		dlm_lock_put(lock);
  		spin_unlock(&dlm->ast_lock);
  
  		if (lock->ml.node != dlm->node_num) {
  			ret = dlm_do_remote_ast(dlm, res, lock);
  			if (ret < 0)
  				mlog_errno(ret);
  		} else
  			dlm_do_local_ast(dlm, res, lock);
  
  		spin_lock(&dlm->ast_lock);
  
  		/* possible that another ast was queued while
  		 * we were delivering the last one */
  		if (!list_empty(&lock->ast_list)) {

  			mlog(0, "%s: res %.*s, AST queued while flushing last "
  			     "one
  ", dlm->name, res->lockname.len,
  			     res->lockname.name);

  		} else
  			lock->ast_pending = 0;
  
  		/* drop the extra ref.
  		 * this may drop it completely. */
  		dlm_lock_put(lock);
  		dlm_lockres_release_ast(dlm, res);
  	}
  
  	while (!list_empty(&dlm->pending_basts)) {
  		lock = list_entry(dlm->pending_basts.next,
  				  struct dlm_lock, bast_list);
  		/* get an extra ref on lock */
  		dlm_lock_get(lock);
  		res = lock->lockres;
  
  		BUG_ON(!lock->bast_pending);
  
  		/* get the highest blocked lock, and reset */
  		spin_lock(&lock->spinlock);
  		BUG_ON(lock->ml.highest_blocked <= LKM_IVMODE);
  		hi = lock->ml.highest_blocked;
  		lock->ml.highest_blocked = LKM_IVMODE;
  		spin_unlock(&lock->spinlock);
  
  		/* remove from list (including ref) */
  		list_del_init(&lock->bast_list);
  		dlm_lock_put(lock);
  		spin_unlock(&dlm->ast_lock);

  		mlog(0, "%s: res %.*s, Flush BAST for lock %u:%llu, "
  		     "blocked %d, node %u
  ",
  		     dlm->name, res->lockname.len, res->lockname.name,
  		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
  		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
  		     hi, lock->ml.node);

  
  		if (lock->ml.node != dlm->node_num) {
  			ret = dlm_send_proxy_bast(dlm, res, lock, hi);
  			if (ret < 0)
  				mlog_errno(ret);
  		} else
  			dlm_do_local_bast(dlm, res, lock, hi);
  
  		spin_lock(&dlm->ast_lock);
  
  		/* possible that another bast was queued while
  		 * we were delivering the last one */
  		if (!list_empty(&lock->bast_list)) {

  			mlog(0, "%s: res %.*s, BAST queued while flushing last "
  			     "one
  ", dlm->name, res->lockname.len,
  			     res->lockname.name);

  		} else
  			lock->bast_pending = 0;
  
  		/* drop the extra ref.
  		 * this may drop it completely. */
  		dlm_lock_put(lock);
  		dlm_lockres_release_ast(dlm, res);
  	}
  	wake_up(&dlm->ast_wq);
  	spin_unlock(&dlm->ast_lock);
  }
  
  
  #define DLM_THREAD_TIMEOUT_MS (4 * 1000)
  #define DLM_THREAD_MAX_DIRTY  100
  #define DLM_THREAD_MAX_ASTS   10
  
  static int dlm_thread(void *data)
  {
  	struct dlm_lock_resource *res;
  	struct dlm_ctxt *dlm = data;
  	unsigned long timeout = msecs_to_jiffies(DLM_THREAD_TIMEOUT_MS);
  
  	mlog(0, "dlm thread running for %s...
  ", dlm->name);
  
  	while (!kthread_should_stop()) {
  		int n = DLM_THREAD_MAX_DIRTY;
  
  		/* dlm_shutting_down is very point-in-time, but that
  		 * doesn't matter as we'll just loop back around if we
  		 * get false on the leading edge of a state
  		 * transition. */
  		dlm_run_purge_list(dlm, dlm_shutting_down(dlm));
  
  		/* We really don't want to hold dlm->spinlock while
  		 * calling dlm_shuffle_lists on each lockres that
  		 * needs to have its queues adjusted and AST/BASTs
  		 * run.  So let's pull each entry off the dirty_list
  		 * and drop dlm->spinlock ASAP.  Once off the list,
  		 * res->spinlock needs to be taken again to protect
  		 * the queues while calling dlm_shuffle_lists.  */
  		spin_lock(&dlm->spinlock);
  		while (!list_empty(&dlm->dirty_list)) {
  			int delay = 0;
  			res = list_entry(dlm->dirty_list.next,
  					 struct dlm_lock_resource, dirty);
  
  			/* peel a lockres off, remove it from the list,
  			 * unset the dirty flag and drop the dlm lock */
  			BUG_ON(!res);
  			dlm_lockres_get(res);
  
  			spin_lock(&res->spinlock);

  			/* We clear the DLM_LOCK_RES_DIRTY state once we shuffle lists below */

  			list_del_init(&res->dirty);
  			spin_unlock(&res->spinlock);
  			spin_unlock(&dlm->spinlock);

  			/* Drop dirty_list ref */
  			dlm_lockres_put(res);

  
  		 	/* lockres can be re-dirtied/re-added to the
  			 * dirty_list in this gap, but that is ok */

  			spin_lock(&dlm->ast_lock);

  			spin_lock(&res->spinlock);
  			if (res->owner != dlm->node_num) {
  				__dlm_print_one_lock_resource(res);

  				mlog(ML_ERROR, "%s: inprog %d, mig %d, reco %d,"
  				     " dirty %d
  ", dlm->name,
  				     !!(res->state & DLM_LOCK_RES_IN_PROGRESS),
  				     !!(res->state & DLM_LOCK_RES_MIGRATING),
  				     !!(res->state & DLM_LOCK_RES_RECOVERING),
  				     !!(res->state & DLM_LOCK_RES_DIRTY));

  			}
  			BUG_ON(res->owner != dlm->node_num);
  
  			/* it is now ok to move lockreses in these states
  			 * to the dirty list, assuming that they will only be
  			 * dirty for a short while. */

  			BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);

  			if (res->state & (DLM_LOCK_RES_IN_PROGRESS |

  					  DLM_LOCK_RES_RECOVERING)) {
  				/* move it to the tail and keep going */

  				res->state &= ~DLM_LOCK_RES_DIRTY;

  				spin_unlock(&res->spinlock);

  				spin_unlock(&dlm->ast_lock);

  				mlog(0, "%s: res %.*s, inprogress, delay list "
  				     "shuffle, state %d
  ", dlm->name,

  				     res->lockname.len, res->lockname.name,
  				     res->state);
  				delay = 1;
  				goto in_progress;
  			}
  
  			/* at this point the lockres is not migrating/
  			 * recovering/in-progress.  we have the lockres
  			 * spinlock and do NOT have the dlm lock.
  			 * safe to reserve/queue asts and run the lists. */

  			/* called while holding lockres lock */
  			dlm_shuffle_lists(dlm, res);

  			res->state &= ~DLM_LOCK_RES_DIRTY;

  			spin_unlock(&res->spinlock);

  			spin_unlock(&dlm->ast_lock);

  
  			dlm_lockres_calc_usage(dlm, res);
  
  in_progress:
  
  			spin_lock(&dlm->spinlock);
  			/* if the lock was in-progress, stick
  			 * it on the back of the list */
  			if (delay) {
  				spin_lock(&res->spinlock);

  				__dlm_dirty_lockres(dlm, res);

  				spin_unlock(&res->spinlock);
  			}
  			dlm_lockres_put(res);
  
  			/* unlikely, but we may need to give time to
  			 * other tasks */
  			if (!--n) {

  				mlog(0, "%s: Throttling dlm thread
  ",
  				     dlm->name);

  				break;
  			}
  		}
  
  		spin_unlock(&dlm->spinlock);
  		dlm_flush_asts(dlm);
  
  		/* yield and continue right away if there is more work to do */
  		if (!n) {

  			cond_resched();

  			continue;
  		}
  
  		wait_event_interruptible_timeout(dlm->dlm_thread_wq,
  						 !dlm_dirty_list_empty(dlm) ||
  						 kthread_should_stop(),
  						 timeout);
  	}
  
  	mlog(0, "quitting DLM thread
  ");
  	return 0;
  }