/* -*- 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/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/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)
{
if (!__dlm_lockres_has_locks(res) &&
(list_empty(&res->dirty) && !(res->state & DLM_LOCK_RES_DIRTY))) {
/* try not to scan the bitmap unless the first two
* conditions are already true */
int bit = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
if (bit >= O2NM_MAX_NODES) {
/* since the bit for dlm->node_num is not
* set, inflight_locks better be zero */
BUG_ON(res->inflight_locks != 0);
return 1;
}
}
return 0;
}
/* 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 int dlm_purge_lockres(struct dlm_ctxt *dlm,
struct dlm_lock_resource *res)
{
int master;
int ret = 0;
spin_lock(&res->spinlock);
if (!__dlm_lockres_unused(res)) {
mlog(0, "%s:%.*s: tried to purge but not unused\n",
dlm->name, res->lockname.len, res->lockname.name);
__dlm_print_one_lock_resource(res);
spin_unlock(&res->spinlock);
BUG();
}
if (res->state & DLM_LOCK_RES_MIGRATING) {
mlog(0, "%s:%.*s: Delay dropref as this lockres is "
"being remastered\n", dlm->name, res->lockname.len,
res->lockname.name);
/* Re-add the lockres to the end of the purge list */
if (!list_empty(&res->purge)) {
list_del_init(&res->purge);
list_add_tail(&res->purge, &dlm->purge_list);
}
spin_unlock(&res->spinlock);
return 0;
}
master = (res->owner == dlm->node_num);
if (!master)
res->state |= DLM_LOCK_RES_DROPPING_REF;
spin_unlock(&res->spinlock);
mlog(0, "purging lockres %.*s, master = %d\n", res->lockname.len,
res->lockname.name, master);
if (!master) {
/* drop spinlock... retake below */
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);
spin_unlock(&res->spinlock);
dlm_lockres_put(res);
dlm->purge_count--;
} else
spin_unlock(&res->spinlock);
__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) {
spin_lock(&res->spinlock);
res->state &= ~DLM_LOCK_RES_DROPPING_REF;
spin_unlock(&res->spinlock);
wake_up(&res->wq);
}
return 0;
}
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);
/* 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 -- there's no need to keep the lockres
* spinlock. */
spin_lock(&lockres->spinlock);
unused = __dlm_lockres_unused(lockres);
spin_unlock(&lockres->spinlock);
if (!unused)
continue;
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 */
break;
}
dlm_lockres_get(lockres);
/* This may drop and reacquire the dlm spinlock if it
* has to do migration. */
if (dlm_purge_lockres(dlm, lockres))
BUG();
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(&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(&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);
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);
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;
}
