linux-stable/fs/dlm/recoverd.c
Guoqing Jiang 9e1b0211c5 dlm: recheck kthread_should_stop() before schedule()
Call schedule() here could make the thread miss wake
up from kthread_stop(), so it is better to recheck
kthread_should_stop() before call schedule(), a symptom
happened when I run indefinite test (which mostly created
clustered raid1, assemble it in other nodes, then stop
them) of clustered raid.

$ ps aux|grep md|grep D
root      4211  0.0  0.0  19760  2220 ?        Ds   02:58   0:00 mdadm -Ssq
$ cat /proc/4211/stack
kthread_stop+0x4d/0x150
dlm_recoverd_stop+0x15/0x20 [dlm]
dlm_release_lockspace+0x2ab/0x460 [dlm]
leave+0xbf/0x150 [md_cluster]
md_cluster_stop+0x18/0x30 [md_mod]
bitmap_free+0x12e/0x140 [md_mod]
bitmap_destroy+0x7f/0x90 [md_mod]
__md_stop+0x21/0xa0 [md_mod]
do_md_stop+0x15f/0x5c0 [md_mod]
md_ioctl+0xa65/0x18a0 [md_mod]
blkdev_ioctl+0x49e/0x8d0
block_ioctl+0x41/0x50
do_vfs_ioctl+0x96/0x5b0
SyS_ioctl+0x79/0x90
entry_SYSCALL_64_fastpath+0x1e/0xad

This maybe not resolve the issue completely since the
KTHREAD_SHOULD_STOP flag could be set between "break"
and "schedule", but at least the chance for the symptom
happen could be reduce a lot (The indefinite test runs
more than 20 hours without problem and it happens easily
without the change).

Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: David Teigland <teigland@redhat.com>
2017-09-25 12:48:10 -05:00

354 lines
8.2 KiB
C

/******************************************************************************
*******************************************************************************
**
** Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
** Copyright (C) 2004-2011 Red Hat, Inc. All rights reserved.
**
** This copyrighted material is made available to anyone wishing to use,
** modify, copy, or redistribute it subject to the terms and conditions
** of the GNU General Public License v.2.
**
*******************************************************************************
******************************************************************************/
#include "dlm_internal.h"
#include "lockspace.h"
#include "member.h"
#include "dir.h"
#include "ast.h"
#include "recover.h"
#include "lowcomms.h"
#include "lock.h"
#include "requestqueue.h"
#include "recoverd.h"
/* If the start for which we're re-enabling locking (seq) has been superseded
by a newer stop (ls_recover_seq), we need to leave locking disabled.
We suspend dlm_recv threads here to avoid the race where dlm_recv a) sees
locking stopped and b) adds a message to the requestqueue, but dlm_recoverd
enables locking and clears the requestqueue between a and b. */
static int enable_locking(struct dlm_ls *ls, uint64_t seq)
{
int error = -EINTR;
down_write(&ls->ls_recv_active);
spin_lock(&ls->ls_recover_lock);
if (ls->ls_recover_seq == seq) {
set_bit(LSFL_RUNNING, &ls->ls_flags);
/* unblocks processes waiting to enter the dlm */
up_write(&ls->ls_in_recovery);
clear_bit(LSFL_RECOVER_LOCK, &ls->ls_flags);
error = 0;
}
spin_unlock(&ls->ls_recover_lock);
up_write(&ls->ls_recv_active);
return error;
}
static int ls_recover(struct dlm_ls *ls, struct dlm_recover *rv)
{
unsigned long start;
int error, neg = 0;
log_rinfo(ls, "dlm_recover %llu", (unsigned long long)rv->seq);
mutex_lock(&ls->ls_recoverd_active);
dlm_callback_suspend(ls);
dlm_clear_toss(ls);
/*
* This list of root rsb's will be the basis of most of the recovery
* routines.
*/
dlm_create_root_list(ls);
/*
* Add or remove nodes from the lockspace's ls_nodes list.
*/
error = dlm_recover_members(ls, rv, &neg);
if (error) {
log_rinfo(ls, "dlm_recover_members error %d", error);
goto fail;
}
dlm_recover_dir_nodeid(ls);
ls->ls_recover_dir_sent_res = 0;
ls->ls_recover_dir_sent_msg = 0;
ls->ls_recover_locks_in = 0;
dlm_set_recover_status(ls, DLM_RS_NODES);
error = dlm_recover_members_wait(ls);
if (error) {
log_rinfo(ls, "dlm_recover_members_wait error %d", error);
goto fail;
}
start = jiffies;
/*
* Rebuild our own share of the directory by collecting from all other
* nodes their master rsb names that hash to us.
*/
error = dlm_recover_directory(ls);
if (error) {
log_rinfo(ls, "dlm_recover_directory error %d", error);
goto fail;
}
dlm_set_recover_status(ls, DLM_RS_DIR);
error = dlm_recover_directory_wait(ls);
if (error) {
log_rinfo(ls, "dlm_recover_directory_wait error %d", error);
goto fail;
}
log_rinfo(ls, "dlm_recover_directory %u out %u messages",
ls->ls_recover_dir_sent_res, ls->ls_recover_dir_sent_msg);
/*
* We may have outstanding operations that are waiting for a reply from
* a failed node. Mark these to be resent after recovery. Unlock and
* cancel ops can just be completed.
*/
dlm_recover_waiters_pre(ls);
error = dlm_recovery_stopped(ls);
if (error)
goto fail;
if (neg || dlm_no_directory(ls)) {
/*
* Clear lkb's for departed nodes.
*/
dlm_recover_purge(ls);
/*
* Get new master nodeid's for rsb's that were mastered on
* departed nodes.
*/
error = dlm_recover_masters(ls);
if (error) {
log_rinfo(ls, "dlm_recover_masters error %d", error);
goto fail;
}
/*
* Send our locks on remastered rsb's to the new masters.
*/
error = dlm_recover_locks(ls);
if (error) {
log_rinfo(ls, "dlm_recover_locks error %d", error);
goto fail;
}
dlm_set_recover_status(ls, DLM_RS_LOCKS);
error = dlm_recover_locks_wait(ls);
if (error) {
log_rinfo(ls, "dlm_recover_locks_wait error %d", error);
goto fail;
}
log_rinfo(ls, "dlm_recover_locks %u in",
ls->ls_recover_locks_in);
/*
* Finalize state in master rsb's now that all locks can be
* checked. This includes conversion resolution and lvb
* settings.
*/
dlm_recover_rsbs(ls);
} else {
/*
* Other lockspace members may be going through the "neg" steps
* while also adding us to the lockspace, in which case they'll
* be doing the recover_locks (RS_LOCKS) barrier.
*/
dlm_set_recover_status(ls, DLM_RS_LOCKS);
error = dlm_recover_locks_wait(ls);
if (error) {
log_rinfo(ls, "dlm_recover_locks_wait error %d", error);
goto fail;
}
}
dlm_release_root_list(ls);
/*
* Purge directory-related requests that are saved in requestqueue.
* All dir requests from before recovery are invalid now due to the dir
* rebuild and will be resent by the requesting nodes.
*/
dlm_purge_requestqueue(ls);
dlm_set_recover_status(ls, DLM_RS_DONE);
error = dlm_recover_done_wait(ls);
if (error) {
log_rinfo(ls, "dlm_recover_done_wait error %d", error);
goto fail;
}
dlm_clear_members_gone(ls);
dlm_adjust_timeouts(ls);
dlm_callback_resume(ls);
error = enable_locking(ls, rv->seq);
if (error) {
log_rinfo(ls, "enable_locking error %d", error);
goto fail;
}
error = dlm_process_requestqueue(ls);
if (error) {
log_rinfo(ls, "dlm_process_requestqueue error %d", error);
goto fail;
}
error = dlm_recover_waiters_post(ls);
if (error) {
log_rinfo(ls, "dlm_recover_waiters_post error %d", error);
goto fail;
}
dlm_recover_grant(ls);
log_rinfo(ls, "dlm_recover %llu generation %u done: %u ms",
(unsigned long long)rv->seq, ls->ls_generation,
jiffies_to_msecs(jiffies - start));
mutex_unlock(&ls->ls_recoverd_active);
dlm_lsop_recover_done(ls);
return 0;
fail:
dlm_release_root_list(ls);
log_rinfo(ls, "dlm_recover %llu error %d",
(unsigned long long)rv->seq, error);
mutex_unlock(&ls->ls_recoverd_active);
return error;
}
/* The dlm_ls_start() that created the rv we take here may already have been
stopped via dlm_ls_stop(); in that case we need to leave the RECOVERY_STOP
flag set. */
static void do_ls_recovery(struct dlm_ls *ls)
{
struct dlm_recover *rv = NULL;
spin_lock(&ls->ls_recover_lock);
rv = ls->ls_recover_args;
ls->ls_recover_args = NULL;
if (rv && ls->ls_recover_seq == rv->seq)
clear_bit(LSFL_RECOVER_STOP, &ls->ls_flags);
spin_unlock(&ls->ls_recover_lock);
if (rv) {
ls_recover(ls, rv);
kfree(rv->nodes);
kfree(rv);
}
}
static int dlm_recoverd(void *arg)
{
struct dlm_ls *ls;
ls = dlm_find_lockspace_local(arg);
if (!ls) {
log_print("dlm_recoverd: no lockspace %p", arg);
return -1;
}
down_write(&ls->ls_in_recovery);
set_bit(LSFL_RECOVER_LOCK, &ls->ls_flags);
wake_up(&ls->ls_recover_lock_wait);
while (1) {
/*
* We call kthread_should_stop() after set_current_state().
* This is because it works correctly if kthread_stop() is
* called just before set_current_state().
*/
set_current_state(TASK_INTERRUPTIBLE);
if (kthread_should_stop()) {
set_current_state(TASK_RUNNING);
break;
}
if (!test_bit(LSFL_RECOVER_WORK, &ls->ls_flags) &&
!test_bit(LSFL_RECOVER_DOWN, &ls->ls_flags)) {
if (kthread_should_stop())
break;
schedule();
}
set_current_state(TASK_RUNNING);
if (test_and_clear_bit(LSFL_RECOVER_DOWN, &ls->ls_flags)) {
down_write(&ls->ls_in_recovery);
set_bit(LSFL_RECOVER_LOCK, &ls->ls_flags);
wake_up(&ls->ls_recover_lock_wait);
}
if (test_and_clear_bit(LSFL_RECOVER_WORK, &ls->ls_flags))
do_ls_recovery(ls);
}
if (test_bit(LSFL_RECOVER_LOCK, &ls->ls_flags))
up_write(&ls->ls_in_recovery);
dlm_put_lockspace(ls);
return 0;
}
int dlm_recoverd_start(struct dlm_ls *ls)
{
struct task_struct *p;
int error = 0;
p = kthread_run(dlm_recoverd, ls, "dlm_recoverd");
if (IS_ERR(p))
error = PTR_ERR(p);
else
ls->ls_recoverd_task = p;
return error;
}
void dlm_recoverd_stop(struct dlm_ls *ls)
{
kthread_stop(ls->ls_recoverd_task);
}
void dlm_recoverd_suspend(struct dlm_ls *ls)
{
wake_up(&ls->ls_wait_general);
mutex_lock(&ls->ls_recoverd_active);
}
void dlm_recoverd_resume(struct dlm_ls *ls)
{
mutex_unlock(&ls->ls_recoverd_active);
}