remarkable-linux/fs/ocfs2/cluster/heartbeat.h
Joseph Qi 70e82a12db ocfs2: fix deadlock between o2hb thread and o2net_wq
The following case may lead to o2net_wq and o2hb thread deadlock on
o2hb_callback_sem.
Currently there are 2 nodes say N1, N2 in the cluster. And N2 down, at
the same time, N3 tries to join the cluster. So N1 will handle node
down (N2) and join (N3) simultaneously.
    o2hb                               o2net_wq
    ->o2hb_do_disk_heartbeat
    ->o2hb_check_slot
    ->o2hb_run_event_list
    ->o2hb_fire_callbacks
    ->down_write(&o2hb_callback_sem)
    ->o2net_hb_node_down_cb
    ->flush_workqueue(o2net_wq)
                                       ->o2net_process_message
                                       ->dlm_query_join_handler
                                       ->o2hb_check_node_heartbeating
                                       ->o2hb_fill_node_map
                                       ->down_read(&o2hb_callback_sem)

No need to take o2hb_callback_sem in dlm_query_join_handler,
o2hb_live_lock is enough to protect live node map.

Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
Cc: xMark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: jiangyiwen <jiangyiwen@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-09 22:25:47 -04:00

91 lines
2.7 KiB
C

/* -*- mode: c; c-basic-offset: 8; -*-
* vim: noexpandtab sw=8 ts=8 sts=0:
*
* heartbeat.h
*
* Function prototypes
*
* 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.
*
*/
#ifndef O2CLUSTER_HEARTBEAT_H
#define O2CLUSTER_HEARTBEAT_H
#include "ocfs2_heartbeat.h"
#define O2HB_REGION_TIMEOUT_MS 2000
#define O2HB_MAX_REGION_NAME_LEN 32
/* number of changes to be seen as live */
#define O2HB_LIVE_THRESHOLD 2
/* number of equal samples to be seen as dead */
extern unsigned int o2hb_dead_threshold;
#define O2HB_DEFAULT_DEAD_THRESHOLD 31
/* Otherwise MAX_WRITE_TIMEOUT will be zero... */
#define O2HB_MIN_DEAD_THRESHOLD 2
#define O2HB_MAX_WRITE_TIMEOUT_MS (O2HB_REGION_TIMEOUT_MS * (o2hb_dead_threshold - 1))
#define O2HB_CB_MAGIC 0x51d1e4ec
/* callback stuff */
enum o2hb_callback_type {
O2HB_NODE_DOWN_CB = 0,
O2HB_NODE_UP_CB,
O2HB_NUM_CB
};
struct o2nm_node;
typedef void (o2hb_cb_func)(struct o2nm_node *, int, void *);
struct o2hb_callback_func {
u32 hc_magic;
struct list_head hc_item;
o2hb_cb_func *hc_func;
void *hc_data;
int hc_priority;
enum o2hb_callback_type hc_type;
};
struct config_group *o2hb_alloc_hb_set(void);
void o2hb_free_hb_set(struct config_group *group);
void o2hb_setup_callback(struct o2hb_callback_func *hc,
enum o2hb_callback_type type,
o2hb_cb_func *func,
void *data,
int priority);
int o2hb_register_callback(const char *region_uuid,
struct o2hb_callback_func *hc);
void o2hb_unregister_callback(const char *region_uuid,
struct o2hb_callback_func *hc);
void o2hb_fill_node_map(unsigned long *map,
unsigned bytes);
void o2hb_exit(void);
int o2hb_init(void);
int o2hb_check_node_heartbeating(u8 node_num);
int o2hb_check_node_heartbeating_no_sem(u8 node_num);
int o2hb_check_node_heartbeating_from_callback(u8 node_num);
int o2hb_check_local_node_heartbeating(void);
void o2hb_stop_all_regions(void);
int o2hb_get_all_regions(char *region_uuids, u8 numregions);
int o2hb_global_heartbeat_active(void);
#endif /* O2CLUSTER_HEARTBEAT_H */