linux/fs/ocfs2/dlm/dlmthread.c
Wengang Wang a524812b7e ocfs2/dlm: avoid incorrect bit set in refmap on recovery master
In the following situation, there remains an incorrect bit in refmap on the
recovery master. Finally the recovery master will fail at purging the lockres
due to the incorrect bit in refmap.

1) node A has no interest on lockres A any longer, so it is purging it.
2) the owner of lockres A is node B, so node A is sending de-ref message
to node B.
3) at this time, node B crashed. node C becomes the recovery master. it recovers
lockres A(because the master is the dead node B).
4) node A migrated lockres A to node C with a refbit there.
5) node A failed to send de-ref message to node B because it crashed. The failure
is ignored. no other action is done for lockres A any more.

For mormal, re-send the deref message to it to recovery master can fix it. Well,
ignoring the failure of deref to the original master and not recovering the lockres
to recovery master has the same effect. And the later is simpler.

Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Acked-by: Srinivas Eeda <srinivas.eeda@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Joel Becker <joel.becker@oracle.com>
2010-08-07 10:49:41 -07:00

758 lines
20 KiB
C

/* -*- 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;
if (__dlm_lockres_has_locks(res))
return 0;
if (!list_empty(&res->dirty) || res->state & DLM_LOCK_RES_DIRTY)
return 0;
if (res->state & DLM_LOCK_RES_RECOVERING)
return 0;
bit = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
if (bit < O2NM_MAX_NODES)
return 0;
/*
* since the bit for dlm->node_num is not set, inflight_locks better
* be zero
*/
BUG_ON(res->inflight_locks != 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)
{
mlog_entry("%.*s\n", res->lockname.len, res->lockname.name);
assert_spin_locked(&dlm->spinlock);
assert_spin_locked(&res->spinlock);
if (__dlm_lockres_unused(res)){
if (list_empty(&res->purge)) {
mlog(0, "putting lockres %.*s:%p onto purge list\n",
res->lockname.len, res->lockname.name, res);
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, "removing lockres %.*s:%p from purge list, owner=%u\n",
res->lockname.len, res->lockname.name, res, res->owner);
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)
{
mlog_entry("%.*s\n", res->lockname.len, res->lockname.name);
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, "purging lockres %.*s, master = %d\n", 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) {
mlog_errno(ret);
if (!dlm_is_host_down(ret))
BUG();
}
mlog(0, "%s:%.*s: dlm_deref_lockres returned %d\n",
dlm->name, res->lockname.len, res->lockname.name, ret);
spin_lock(&dlm->spinlock);
spin_lock(&res->spinlock);
}
if (!list_empty(&res->purge)) {
mlog(0, "removing lockres %.*s:%p from purgelist, "
"master = %d\n", res->lockname.len, res->lockname.name,
res, master);
list_del_init(&res->purge);
dlm_lockres_put(res);
dlm->purge_count--;
}
if (!__dlm_lockres_unused(res)) {
mlog(ML_ERROR, "found lockres %s:%.*s: in use after deref\n",
dlm->name, res->lockname.len, res->lockname.name);
__dlm_print_one_lock_resource(res);
BUG();
}
__dlm_unhash_lockres(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, "lockres %s:%.*s: is in use or "
"being remastered, used %d, state %d\n",
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;
//mlog(0, "res->lockname.len=%d\n", res->lockname.len);
//mlog(0, "res->lockname.name=%p\n", res->lockname.name);
//mlog(0, "shuffle res %.*s\n", res->lockname.len,
// res->lockname.name);
/* 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, "res %.*s has locks on a convert queue\n", 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: converting a lock with no "
"convert_type!\n", 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, "calling ast for converting lock: %.*s, have: %d, "
"granting: %d, node: %u\n", res->lockname.len,
res->lockname.name, 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, "calling ast for blocked lock: %.*s, granting: %d, "
"node: %u\n", res->lockname.len, res->lockname.name,
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)
{
mlog_entry("dlm=%p, res=%p\n", dlm, 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)
{
mlog_entry("dlm=%p, res=%p\n", dlm, 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;
}
}
}
/* Launch the NM thread for the mounted volume */
int dlm_launch_thread(struct dlm_ctxt *dlm)
{
mlog(0, "starting dlm thread...\n");
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\n");
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, "delivering an ast for this lockres\n");
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, "aha another ast got queued while "
"we were finishing the last one. will "
"keep the ast_pending flag set.\n");
} 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, "delivering a bast for this lockres "
"(blocked = %d\n", hi);
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, "aha another bast got queued while "
"we were finishing the last one. will "
"keep the bast_pending flag set.\n");
} 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...\n", 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, "inprog:%s, mig:%s, reco:%s, dirty:%s\n",
res->state & DLM_LOCK_RES_IN_PROGRESS ? "yes" : "no",
res->state & DLM_LOCK_RES_MIGRATING ? "yes" : "no",
res->state & DLM_LOCK_RES_RECOVERING ? "yes" : "no",
res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
}
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, "delaying list shuffling for in-"
"progress lockres %.*s, state=%d\n",
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. */
mlog(0, "calling dlm_shuffle_lists with dlm=%s, "
"res=%.*s\n", dlm->name,
res->lockname.len, res->lockname.name);
/* 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, "throttling dlm_thread\n");
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\n");
return 0;
}