1	// SPDX-License-Identifier: GPL-2.0-or-later
2	/*
3	* Copyright (C) 2004, 2005 Oracle. All rights reserved.
4	*/
5
6	#include <linux/kernel.h>
7	#include <linux/sched.h>
8	#include <linux/jiffies.h>
9	#include <linux/module.h>
10	#include <linux/fs.h>
11	#include <linux/bio.h>
12	#include <linux/blkdev.h>
13	#include <linux/delay.h>
14	#include <linux/file.h>
15	#include <linux/kthread.h>
16	#include <linux/configfs.h>
17	#include <linux/random.h>
18	#include <linux/crc32.h>
19	#include <linux/time.h>
20	#include <linux/debugfs.h>
21	#include <linux/slab.h>
22	#include <linux/bitmap.h>
23	#include <linux/ktime.h>
24	#include "heartbeat.h"
25	#include "tcp.h"
26	#include "nodemanager.h"
27	#include "quorum.h"
28
29	#include "masklog.h"
30
31
32	/*
33	* The first heartbeat pass had one global thread that would serialize all hb
34	* callback calls. This global serializing sem should only be removed once
35	* we've made sure that all callees can deal with being called concurrently
36	* from multiple hb region threads.
37	*/
38	static DECLARE_RWSEM(o2hb_callback_sem);
39
40	/*
41	* multiple hb threads are watching multiple regions. A node is live
42	* whenever any of the threads sees activity from the node in its region.
43	*/
44	static DEFINE_SPINLOCK(o2hb_live_lock);
45	static struct list_head o2hb_live_slots[O2NM_MAX_NODES];
46	static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
47	static LIST_HEAD(o2hb_node_events);
48	static DECLARE_WAIT_QUEUE_HEAD(o2hb_steady_queue);
49
50	/*
51	* In global heartbeat, we maintain a series of region bitmaps.
52	* - o2hb_region_bitmap allows us to limit the region number to max region.
53	* - o2hb_live_region_bitmap tracks live regions (seen steady iterations).
54	* - o2hb_quorum_region_bitmap tracks live regions that have seen all nodes
55	* heartbeat on it.
56	* - o2hb_failed_region_bitmap tracks the regions that have seen io timeouts.
57	*/
58	static unsigned long o2hb_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
59	static unsigned long o2hb_live_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
60	static unsigned long o2hb_quorum_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
61	static unsigned long o2hb_failed_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
62
63	#define O2HB_DB_TYPE_LIVENODES 0
64	#define O2HB_DB_TYPE_LIVEREGIONS 1
65	#define O2HB_DB_TYPE_QUORUMREGIONS 2
66	#define O2HB_DB_TYPE_FAILEDREGIONS 3
67	#define O2HB_DB_TYPE_REGION_LIVENODES 4
68	#define O2HB_DB_TYPE_REGION_NUMBER 5
69	#define O2HB_DB_TYPE_REGION_ELAPSED_TIME 6
70	#define O2HB_DB_TYPE_REGION_PINNED 7
71	struct o2hb_debug_buf {
72	int db_type;
73	int db_size;
74	int db_len;
75	void *db_data;
76	};
77
78	static struct o2hb_debug_buf *o2hb_db_livenodes;
79	static struct o2hb_debug_buf *o2hb_db_liveregions;
80	static struct o2hb_debug_buf *o2hb_db_quorumregions;
81	static struct o2hb_debug_buf *o2hb_db_failedregions;
82
83	#define O2HB_DEBUG_DIR "o2hb"
84	#define O2HB_DEBUG_LIVENODES "livenodes"
85	#define O2HB_DEBUG_LIVEREGIONS "live_regions"
86	#define O2HB_DEBUG_QUORUMREGIONS "quorum_regions"
87	#define O2HB_DEBUG_FAILEDREGIONS "failed_regions"
88	#define O2HB_DEBUG_REGION_NUMBER "num"
89	#define O2HB_DEBUG_REGION_ELAPSED_TIME "elapsed_time_in_ms"
90	#define O2HB_DEBUG_REGION_PINNED "pinned"
91
92	static struct dentry *o2hb_debug_dir;
93
94	static LIST_HEAD(o2hb_all_regions);
95
96	static struct o2hb_callback {
97	struct list_head list;
98	} o2hb_callbacks[O2HB_NUM_CB];
99
100	static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type);
101
102	enum o2hb_heartbeat_modes {
103	O2HB_HEARTBEAT_LOCAL = 0,
104	O2HB_HEARTBEAT_GLOBAL,
105	O2HB_HEARTBEAT_NUM_MODES,
106	};
107
108	static const char *o2hb_heartbeat_mode_desc[O2HB_HEARTBEAT_NUM_MODES] = {
109	"local", /* O2HB_HEARTBEAT_LOCAL */
110	"global", /* O2HB_HEARTBEAT_GLOBAL */
111	};
112
113	unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
114	static unsigned int o2hb_heartbeat_mode = O2HB_HEARTBEAT_LOCAL;
115
116	/*
117	* o2hb_dependent_users tracks the number of registered callbacks that depend
118	* on heartbeat. o2net and o2dlm are two entities that register this callback.
119	* However only o2dlm depends on the heartbeat. It does not want the heartbeat
120	* to stop while a dlm domain is still active.
121	*/
122	static unsigned int o2hb_dependent_users;
123
124	/*
125	* In global heartbeat mode, all regions are pinned if there are one or more
126	* dependent users and the quorum region count is <= O2HB_PIN_CUT_OFF. All
127	* regions are unpinned if the region count exceeds the cut off or the number
128	* of dependent users falls to zero.
129	*/
130	#define O2HB_PIN_CUT_OFF 3
131
132	/*
133	* In local heartbeat mode, we assume the dlm domain name to be the same as
134	* region uuid. This is true for domains created for the file system but not
135	* necessarily true for userdlm domains. This is a known limitation.
136	*
137	* In global heartbeat mode, we pin/unpin all o2hb regions. This solution
138	* works for both file system and userdlm domains.
139	*/
140	static int o2hb_region_pin(const char *region_uuid);
141	static void o2hb_region_unpin(const char *region_uuid);
142
143	/* Only sets a new threshold if there are no active regions.
144	*
145	* No locking or otherwise interesting code is required for reading
146	* o2hb_dead_threshold as it can't change once regions are active and
147	* it's not interesting to anyone until then anyway. */
148	static void o2hb_dead_threshold_set(unsigned int threshold)
149	{
150	if (threshold > O2HB_MIN_DEAD_THRESHOLD) {
151	spin_lock(lock: &o2hb_live_lock);
152	if (list_empty(head: &o2hb_all_regions))
153	o2hb_dead_threshold = threshold;
154	spin_unlock(lock: &o2hb_live_lock);
155	}
156	}
157
158	static int o2hb_global_heartbeat_mode_set(unsigned int hb_mode)
159	{
160	int ret = -1;
161
162	if (hb_mode < O2HB_HEARTBEAT_NUM_MODES) {
163	spin_lock(lock: &o2hb_live_lock);
164	if (list_empty(head: &o2hb_all_regions)) {
165	o2hb_heartbeat_mode = hb_mode;
166	ret = 0;
167	}
168	spin_unlock(lock: &o2hb_live_lock);
169	}
170
171	return ret;
172	}
173
174	struct o2hb_node_event {
175	struct list_head hn_item;
176	enum o2hb_callback_type hn_event_type;
177	struct o2nm_node *hn_node;
178	int hn_node_num;
179	};
180
181	struct o2hb_disk_slot {
182	struct o2hb_disk_heartbeat_block *ds_raw_block;
183	u8 ds_node_num;
184	u64 ds_last_time;
185	u64 ds_last_generation;
186	u16 ds_equal_samples;
187	u16 ds_changed_samples;
188	struct list_head ds_live_item;
189	};
190
191	/* each thread owns a region.. when we're asked to tear down the region
192	* we ask the thread to stop, who cleans up the region */
193	struct o2hb_region {
194	struct config_item hr_item;
195
196	struct list_head hr_all_item;
197	unsigned hr_unclean_stop:1,
198	hr_aborted_start:1,
199	hr_item_pinned:1,
200	hr_item_dropped:1,
201	hr_node_deleted:1;
202
203	/* protected by the hr_callback_sem */
204	struct task_struct *hr_task;
205
206	unsigned int hr_blocks;
207	unsigned long long hr_start_block;
208
209	unsigned int hr_block_bits;
210	unsigned int hr_block_bytes;
211
212	unsigned int hr_slots_per_page;
213	unsigned int hr_num_pages;
214
215	struct page **hr_slot_data;
216	struct file *hr_bdev_file;
217	struct o2hb_disk_slot *hr_slots;
218
219	/* live node map of this region */
220	unsigned long hr_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
221	unsigned int hr_region_num;
222
223	struct dentry *hr_debug_dir;
224	struct o2hb_debug_buf *hr_db_livenodes;
225	struct o2hb_debug_buf *hr_db_regnum;
226	struct o2hb_debug_buf *hr_db_elapsed_time;
227	struct o2hb_debug_buf *hr_db_pinned;
228
229	/* let the person setting up hb wait for it to return until it
230	* has reached a 'steady' state. This will be fixed when we have
231	* a more complete api that doesn't lead to this sort of fragility. */
232	atomic_t hr_steady_iterations;
233
234	/* terminate o2hb thread if it does not reach steady state
235	* (hr_steady_iterations == 0) within hr_unsteady_iterations */
236	atomic_t hr_unsteady_iterations;
237
238	unsigned int hr_timeout_ms;
239
240	/* randomized as the region goes up and down so that a node
241	* recognizes a node going up and down in one iteration */
242	u64 hr_generation;
243
244	struct delayed_work hr_write_timeout_work;
245	unsigned long hr_last_timeout_start;
246
247	/* negotiate timer, used to negotiate extending hb timeout. */
248	struct delayed_work hr_nego_timeout_work;
249	unsigned long hr_nego_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
250
251	/* Used during o2hb_check_slot to hold a copy of the block
252	* being checked because we temporarily have to zero out the
253	* crc field. */
254	struct o2hb_disk_heartbeat_block *hr_tmp_block;
255
256	/* Message key for negotiate timeout message. */
257	unsigned int hr_key;
258	struct list_head hr_handler_list;
259
260	/* last hb status, 0 for success, other value for error. */
261	int hr_last_hb_status;
262	};
263
264	static inline struct block_device *reg_bdev(struct o2hb_region *reg)
265	{
266	return reg->hr_bdev_file ? file_bdev(bdev_file: reg->hr_bdev_file) : NULL;
267	}
268
269	struct o2hb_bio_wait_ctxt {
270	atomic_t wc_num_reqs;
271	struct completion wc_io_complete;
272	int wc_error;
273	};
274
275	#define O2HB_NEGO_TIMEOUT_MS (O2HB_MAX_WRITE_TIMEOUT_MS/2)
276
277	enum {
278	O2HB_NEGO_TIMEOUT_MSG = 1,
279	O2HB_NEGO_APPROVE_MSG = 2,
280	};
281
282	struct o2hb_nego_msg {
283	u8 node_num;
284	};
285
286	static void o2hb_write_timeout(struct work_struct *work)
287	{
288	int failed, quorum;
289	struct o2hb_region *reg =
290	container_of(work, struct o2hb_region,
291	hr_write_timeout_work.work);
292
293	mlog(ML_ERROR, "Heartbeat write timeout to device %pg after %u "
294	"milliseconds\n", reg_bdev(reg),
295	jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
296
297	if (o2hb_global_heartbeat_active()) {
298	spin_lock(lock: &o2hb_live_lock);
299	if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
300	set_bit(nr: reg->hr_region_num, addr: o2hb_failed_region_bitmap);
301	failed = bitmap_weight(src: o2hb_failed_region_bitmap,
302	O2NM_MAX_REGIONS);
303	quorum = bitmap_weight(src: o2hb_quorum_region_bitmap,
304	O2NM_MAX_REGIONS);
305	spin_unlock(lock: &o2hb_live_lock);
306
307	mlog(ML_HEARTBEAT, "Number of regions %d, failed regions %d\n",
308	quorum, failed);
309
310	/*
311	* Fence if the number of failed regions >= half the number
312	* of quorum regions
313	*/
314	if ((failed << 1) < quorum)
315	return;
316	}
317
318	o2quo_disk_timeout();
319	}
320
321	static void o2hb_arm_timeout(struct o2hb_region *reg)
322	{
323	/* Arm writeout only after thread reaches steady state */
324	if (atomic_read(v: &reg->hr_steady_iterations) != 0)
325	return;
326
327	mlog(ML_HEARTBEAT, "Queue write timeout for %u ms\n",
328	O2HB_MAX_WRITE_TIMEOUT_MS);
329
330	if (o2hb_global_heartbeat_active()) {
331	spin_lock(lock: &o2hb_live_lock);
332	clear_bit(nr: reg->hr_region_num, addr: o2hb_failed_region_bitmap);
333	spin_unlock(lock: &o2hb_live_lock);
334	}
335	cancel_delayed_work(dwork: &reg->hr_write_timeout_work);
336	schedule_delayed_work(dwork: &reg->hr_write_timeout_work,
337	delay: msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
338
339	cancel_delayed_work(dwork: &reg->hr_nego_timeout_work);
340	/* negotiate timeout must be less than write timeout. */
341	schedule_delayed_work(dwork: &reg->hr_nego_timeout_work,
342	delay: msecs_to_jiffies(O2HB_NEGO_TIMEOUT_MS));
343	bitmap_zero(dst: reg->hr_nego_node_bitmap, O2NM_MAX_NODES);
344	}
345
346	static void o2hb_disarm_timeout(struct o2hb_region *reg)
347	{
348	cancel_delayed_work_sync(dwork: &reg->hr_write_timeout_work);
349	cancel_delayed_work_sync(dwork: &reg->hr_nego_timeout_work);
350	}
351
352	static int o2hb_send_nego_msg(int key, int type, u8 target)
353	{
354	struct o2hb_nego_msg msg;
355	int status, ret;
356
357	msg.node_num = o2nm_this_node();
358	again:
359	ret = o2net_send_message(msg_type: type, key, data: &msg, len: sizeof(msg),
360	target_node: target, status: &status);
361
362	if (ret == -EAGAIN || ret == -ENOMEM) {
363	msleep(msecs: 100);
364	goto again;
365	}
366
367	return ret;
368	}
369
370	static void o2hb_nego_timeout(struct work_struct *work)
371	{
372	unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
373	int master_node, i, ret;
374	struct o2hb_region *reg;
375
376	reg = container_of(work, struct o2hb_region, hr_nego_timeout_work.work);
377	/* don't negotiate timeout if last hb failed since it is very
378	* possible io failed. Should let write timeout fence self.
379	*/
380	if (reg->hr_last_hb_status)
381	return;
382
383	o2hb_fill_node_map(map: live_node_bitmap, O2NM_MAX_NODES);
384	/* lowest node as master node to make negotiate decision. */
385	master_node = find_first_bit(addr: live_node_bitmap, O2NM_MAX_NODES);
386
387	if (master_node == o2nm_this_node()) {
388	if (!test_bit(master_node, reg->hr_nego_node_bitmap)) {
389	printk(KERN_NOTICE "o2hb: node %d hb write hung for %ds on region %s (%pg).\n",
390	o2nm_this_node(), O2HB_NEGO_TIMEOUT_MS/1000,
391	config_item_name(&reg->hr_item), reg_bdev(reg));
392	set_bit(nr: master_node, addr: reg->hr_nego_node_bitmap);
393	}
394	if (!bitmap_equal(src1: reg->hr_nego_node_bitmap, src2: live_node_bitmap,
395	O2NM_MAX_NODES)) {
396	/* check negotiate bitmap every second to do timeout
397	* approve decision.
398	*/
399	schedule_delayed_work(dwork: &reg->hr_nego_timeout_work,
400	delay: msecs_to_jiffies(m: 1000));
401
402	return;
403	}
404
405	printk(KERN_NOTICE "o2hb: all nodes hb write hung, maybe region %s (%pg) is down.\n",
406	config_item_name(&reg->hr_item),
407	reg_bdev(reg));
408	/* approve negotiate timeout request. */
409	o2hb_arm_timeout(reg);
410
411	i = -1;
412	while ((i = find_next_bit(addr: live_node_bitmap,
413	O2NM_MAX_NODES, offset: i + 1)) < O2NM_MAX_NODES) {
414	if (i == master_node)
415	continue;
416
417	mlog(ML_HEARTBEAT, "send NEGO_APPROVE msg to node %d\n", i);
418	ret = o2hb_send_nego_msg(key: reg->hr_key,
419	type: O2HB_NEGO_APPROVE_MSG, target: i);
420	if (ret)
421	mlog(ML_ERROR, "send NEGO_APPROVE msg to node %d fail %d\n",
422	i, ret);
423	}
424	} else {
425	/* negotiate timeout with master node. */
426	printk(KERN_NOTICE "o2hb: node %d hb write hung for %ds on region %s (%pg), negotiate timeout with node %d.\n",
427	o2nm_this_node(), O2HB_NEGO_TIMEOUT_MS/1000, config_item_name(&reg->hr_item),
428	reg_bdev(reg), master_node);
429	ret = o2hb_send_nego_msg(key: reg->hr_key, type: O2HB_NEGO_TIMEOUT_MSG,
430	target: master_node);
431	if (ret)
432	mlog(ML_ERROR, "send NEGO_TIMEOUT msg to node %d fail %d\n",
433	master_node, ret);
434	}
435	}
436
437	static int o2hb_nego_timeout_handler(struct o2net_msg *msg, u32 len, void *data,
438	void **ret_data)
439	{
440	struct o2hb_region *reg = data;
441	struct o2hb_nego_msg *nego_msg;
442
443	nego_msg = (struct o2hb_nego_msg *)msg->buf;
444	printk(KERN_NOTICE "o2hb: receive negotiate timeout message from node %d on region %s (%pg).\n",
445	nego_msg->node_num, config_item_name(&reg->hr_item),
446	reg_bdev(reg));
447	if (nego_msg->node_num < O2NM_MAX_NODES)
448	set_bit(nr: nego_msg->node_num, addr: reg->hr_nego_node_bitmap);
449	else
450	mlog(ML_ERROR, "got nego timeout message from bad node.\n");
451
452	return 0;
453	}
454
455	static int o2hb_nego_approve_handler(struct o2net_msg *msg, u32 len, void *data,
456	void **ret_data)
457	{
458	struct o2hb_region *reg = data;
459
460	printk(KERN_NOTICE "o2hb: negotiate timeout approved by master node on region %s (%pg).\n",
461	config_item_name(&reg->hr_item), reg_bdev(reg));
462	o2hb_arm_timeout(reg);
463	return 0;
464	}
465
466	static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
467	{
468	atomic_set(v: &wc->wc_num_reqs, i: 1);
469	init_completion(x: &wc->wc_io_complete);
470	wc->wc_error = 0;
471	}
472
473	/* Used in error paths too */
474	static inline void o2hb_bio_wait_dec(struct o2hb_bio_wait_ctxt *wc,
475	unsigned int num)
476	{
477	/* sadly atomic_sub_and_test() isn't available on all platforms. The
478	* good news is that the fast path only completes one at a time */
479	while(num--) {
480	if (atomic_dec_and_test(v: &wc->wc_num_reqs)) {
481	BUG_ON(num > 0);
482	complete(&wc->wc_io_complete);
483	}
484	}
485	}
486
487	static void o2hb_wait_on_io(struct o2hb_bio_wait_ctxt *wc)
488	{
489	o2hb_bio_wait_dec(wc, num: 1);
490	wait_for_completion(&wc->wc_io_complete);
491	}
492
493	static void o2hb_bio_end_io(struct bio *bio)
494	{
495	struct o2hb_bio_wait_ctxt *wc = bio->bi_private;
496
497	if (bio->bi_status) {
498	mlog(ML_ERROR, "IO Error %d\n", bio->bi_status);
499	wc->wc_error = blk_status_to_errno(status: bio->bi_status);
500	}
501
502	o2hb_bio_wait_dec(wc, num: 1);
503	bio_put(bio);
504	}
505
506	/* Setup a Bio to cover I/O against num_slots slots starting at
507	* start_slot. */
508	static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
509	struct o2hb_bio_wait_ctxt *wc,
510	unsigned int *current_slot,
511	unsigned int max_slots, blk_opf_t opf)
512	{
513	int len, current_page;
514	unsigned int vec_len, vec_start;
515	unsigned int bits = reg->hr_block_bits;
516	unsigned int spp = reg->hr_slots_per_page;
517	unsigned int cs = *current_slot;
518	struct bio *bio;
519	struct page *page;
520
521	/* Testing has shown this allocation to take long enough under
522	* GFP_KERNEL that the local node can get fenced. It would be
523	* nicest if we could pre-allocate these bios and avoid this
524	* all together. */
525	bio = bio_alloc(bdev: reg_bdev(reg), nr_vecs: 16, opf, GFP_ATOMIC);
526	if (!bio) {
527	mlog(ML_ERROR, "Could not alloc slots BIO!\n");
528	bio = ERR_PTR(error: -ENOMEM);
529	goto bail;
530	}
531
532	/* Must put everything in 512 byte sectors for the bio... */
533	bio->bi_iter.bi_sector = (reg->hr_start_block + cs) << (bits - 9);
534	bio->bi_private = wc;
535	bio->bi_end_io = o2hb_bio_end_io;
536
537	vec_start = (cs << bits) % PAGE_SIZE;
538	while(cs < max_slots) {
539	current_page = cs / spp;
540	page = reg->hr_slot_data[current_page];
541
542	vec_len = min(PAGE_SIZE - vec_start,
543	(max_slots-cs) * (PAGE_SIZE/spp) );
544
545	mlog(ML_HB_BIO, "page %d, vec_len = %u, vec_start = %u\n",
546	current_page, vec_len, vec_start);
547
548	len = bio_add_page(bio, page, len: vec_len, off: vec_start);
549	if (len != vec_len) break;
550
551	cs += vec_len / (PAGE_SIZE/spp);
552	vec_start = 0;
553	}
554
555	bail:
556	*current_slot = cs;
557	return bio;
558	}
559
560	static int o2hb_read_slots(struct o2hb_region *reg,
561	unsigned int begin_slot,
562	unsigned int max_slots)
563	{
564	unsigned int current_slot = begin_slot;
565	int status;
566	struct o2hb_bio_wait_ctxt wc;
567	struct bio *bio;
568
569	o2hb_bio_wait_init(wc: &wc);
570
571	while(current_slot < max_slots) {
572	bio = o2hb_setup_one_bio(reg, wc: &wc, current_slot: &current_slot, max_slots,
573	opf: REQ_OP_READ);
574	if (IS_ERR(ptr: bio)) {
575	status = PTR_ERR(ptr: bio);
576	mlog_errno(status);
577	goto bail_and_wait;
578	}
579
580	atomic_inc(v: &wc.wc_num_reqs);
581	submit_bio(bio);
582	}
583
584	status = 0;
585
586	bail_and_wait:
587	o2hb_wait_on_io(wc: &wc);
588	if (wc.wc_error && !status)
589	status = wc.wc_error;
590
591	return status;
592	}
593
594	static int o2hb_issue_node_write(struct o2hb_region *reg,
595	struct o2hb_bio_wait_ctxt *write_wc)
596	{
597	int status;
598	unsigned int slot;
599	struct bio *bio;
600
601	o2hb_bio_wait_init(wc: write_wc);
602
603	slot = o2nm_this_node();
604
605	bio = o2hb_setup_one_bio(reg, wc: write_wc, current_slot: &slot, max_slots: slot+1,
606	opf: REQ_OP_WRITE | REQ_SYNC);
607	if (IS_ERR(ptr: bio)) {
608	status = PTR_ERR(ptr: bio);
609	mlog_errno(status);
610	goto bail;
611	}
612
613	atomic_inc(v: &write_wc->wc_num_reqs);
614	submit_bio(bio);
615
616	status = 0;
617	bail:
618	return status;
619	}
620
621	static u32 o2hb_compute_block_crc_le(struct o2hb_region *reg,
622	struct o2hb_disk_heartbeat_block *hb_block)
623	{
624	__le32 old_cksum;
625	u32 ret;
626
627	/* We want to compute the block crc with a 0 value in the
628	* hb_cksum field. Save it off here and replace after the
629	* crc. */
630	old_cksum = hb_block->hb_cksum;
631	hb_block->hb_cksum = 0;
632
633	ret = crc32_le(crc: 0, p: (unsigned char *) hb_block, len: reg->hr_block_bytes);
634
635	hb_block->hb_cksum = old_cksum;
636
637	return ret;
638	}
639
640	static void o2hb_dump_slot(struct o2hb_disk_heartbeat_block *hb_block)
641	{
642	mlog(ML_ERROR, "Dump slot information: seq = 0x%llx, node = %u, "
643	"cksum = 0x%x, generation 0x%llx\n",
644	(long long)le64_to_cpu(hb_block->hb_seq),
645	hb_block->hb_node, le32_to_cpu(hb_block->hb_cksum),
646	(long long)le64_to_cpu(hb_block->hb_generation));
647	}
648
649	static int o2hb_verify_crc(struct o2hb_region *reg,
650	struct o2hb_disk_heartbeat_block *hb_block)
651	{
652	u32 read, computed;
653
654	read = le32_to_cpu(hb_block->hb_cksum);
655	computed = o2hb_compute_block_crc_le(reg, hb_block);
656
657	return read == computed;
658	}
659
660	/*
661	* Compare the slot data with what we wrote in the last iteration.
662	* If the match fails, print an appropriate error message. This is to
663	* detect errors like... another node hearting on the same slot,
664	* flaky device that is losing writes, etc.
665	* Returns 1 if check succeeds, 0 otherwise.
666	*/
667	static int o2hb_check_own_slot(struct o2hb_region *reg)
668	{
669	struct o2hb_disk_slot *slot;
670	struct o2hb_disk_heartbeat_block *hb_block;
671	char *errstr;
672
673	slot = &reg->hr_slots[o2nm_this_node()];
674	/* Don't check on our 1st timestamp */
675	if (!slot->ds_last_time)
676	return 0;
677
678	hb_block = slot->ds_raw_block;
679	if (le64_to_cpu(hb_block->hb_seq) == slot->ds_last_time &&
680	le64_to_cpu(hb_block->hb_generation) == slot->ds_last_generation &&
681	hb_block->hb_node == slot->ds_node_num)
682	return 1;
683
684	#define ERRSTR1 "Another node is heartbeating on device"
685	#define ERRSTR2 "Heartbeat generation mismatch on device"
686	#define ERRSTR3 "Heartbeat sequence mismatch on device"
687
688	if (hb_block->hb_node != slot->ds_node_num)
689	errstr = ERRSTR1;
690	else if (le64_to_cpu(hb_block->hb_generation) !=
691	slot->ds_last_generation)
692	errstr = ERRSTR2;
693	else
694	errstr = ERRSTR3;
695
696	mlog(ML_ERROR, "%s (%pg): expected(%u:0x%llx, 0x%llx), "
697	"ondisk(%u:0x%llx, 0x%llx)\n", errstr, reg_bdev(reg),
698	slot->ds_node_num, (unsigned long long)slot->ds_last_generation,
699	(unsigned long long)slot->ds_last_time, hb_block->hb_node,
700	(unsigned long long)le64_to_cpu(hb_block->hb_generation),
701	(unsigned long long)le64_to_cpu(hb_block->hb_seq));
702
703	return 0;
704	}
705
706	static inline void o2hb_prepare_block(struct o2hb_region *reg,
707	u64 generation)
708	{
709	int node_num;
710	u64 cputime;
711	struct o2hb_disk_slot *slot;
712	struct o2hb_disk_heartbeat_block *hb_block;
713
714	node_num = o2nm_this_node();
715	slot = &reg->hr_slots[node_num];
716
717	hb_block = (struct o2hb_disk_heartbeat_block *)slot->ds_raw_block;
718	memset(hb_block, 0, reg->hr_block_bytes);
719	/* TODO: time stuff */
720	cputime = ktime_get_real_seconds();
721	if (!cputime)
722	cputime = 1;
723
724	hb_block->hb_seq = cpu_to_le64(cputime);
725	hb_block->hb_node = node_num;
726	hb_block->hb_generation = cpu_to_le64(generation);
727	hb_block->hb_dead_ms = cpu_to_le32(o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS);
728
729	/* This step must always happen last! */
730	hb_block->hb_cksum = cpu_to_le32(o2hb_compute_block_crc_le(reg,
731	hb_block));
732
733	mlog(ML_HB_BIO, "our node generation = 0x%llx, cksum = 0x%x\n",
734	(long long)generation,
735	le32_to_cpu(hb_block->hb_cksum));
736	}
737
738	static void o2hb_fire_callbacks(struct o2hb_callback *hbcall,
739	struct o2nm_node *node,
740	int idx)
741	{
742	struct o2hb_callback_func *f;
743
744	list_for_each_entry(f, &hbcall->list, hc_item) {
745	mlog(ML_HEARTBEAT, "calling funcs %p\n", f);
746	(f->hc_func)(node, idx, f->hc_data);
747	}
748	}
749
750	/* Will run the list in order until we process the passed event */
751	static void o2hb_run_event_list(struct o2hb_node_event *queued_event)
752	{
753	struct o2hb_callback *hbcall;
754	struct o2hb_node_event *event;
755
756	/* Holding callback sem assures we don't alter the callback
757	* lists when doing this, and serializes ourselves with other
758	* processes wanting callbacks. */
759	down_write(sem: &o2hb_callback_sem);
760
761	spin_lock(lock: &o2hb_live_lock);
762	while (!list_empty(head: &o2hb_node_events)
763	&& !list_empty(head: &queued_event->hn_item)) {
764	event = list_entry(o2hb_node_events.next,
765	struct o2hb_node_event,
766	hn_item);
767	list_del_init(entry: &event->hn_item);
768	spin_unlock(lock: &o2hb_live_lock);
769
770	mlog(ML_HEARTBEAT, "Node %s event for %d\n",
771	event->hn_event_type == O2HB_NODE_UP_CB ? "UP" : "DOWN",
772	event->hn_node_num);
773
774	hbcall = hbcall_from_type(type: event->hn_event_type);
775
776	/* We should *never* have gotten on to the list with a
777	* bad type... This isn't something that we should try
778	* to recover from. */
779	BUG_ON(IS_ERR(hbcall));
780
781	o2hb_fire_callbacks(hbcall, node: event->hn_node, idx: event->hn_node_num);
782
783	spin_lock(lock: &o2hb_live_lock);
784	}
785	spin_unlock(lock: &o2hb_live_lock);
786
787	up_write(sem: &o2hb_callback_sem);
788	}
789
790	static void o2hb_queue_node_event(struct o2hb_node_event *event,
791	enum o2hb_callback_type type,
792	struct o2nm_node *node,
793	int node_num)
794	{
795	assert_spin_locked(&o2hb_live_lock);
796
797	BUG_ON((!node) && (type != O2HB_NODE_DOWN_CB));
798
799	event->hn_event_type = type;
800	event->hn_node = node;
801	event->hn_node_num = node_num;
802
803	mlog(ML_HEARTBEAT, "Queue node %s event for node %d\n",
804	type == O2HB_NODE_UP_CB ? "UP" : "DOWN", node_num);
805
806	list_add_tail(new: &event->hn_item, head: &o2hb_node_events);
807	}
808
809	static void o2hb_shutdown_slot(struct o2hb_disk_slot *slot)
810	{
811	struct o2hb_node_event event =
812	{ .hn_item = LIST_HEAD_INIT(event.hn_item), };
813	struct o2nm_node *node;
814	int queued = 0;
815
816	node = o2nm_get_node_by_num(node_num: slot->ds_node_num);
817	if (!node)
818	return;
819
820	spin_lock(lock: &o2hb_live_lock);
821	if (!list_empty(head: &slot->ds_live_item)) {
822	mlog(ML_HEARTBEAT, "Shutdown, node %d leaves region\n",
823	slot->ds_node_num);
824
825	list_del_init(entry: &slot->ds_live_item);
826
827	if (list_empty(head: &o2hb_live_slots[slot->ds_node_num])) {
828	clear_bit(nr: slot->ds_node_num, addr: o2hb_live_node_bitmap);
829
830	o2hb_queue_node_event(event: &event, type: O2HB_NODE_DOWN_CB, node,
831	node_num: slot->ds_node_num);
832	queued = 1;
833	}
834	}
835	spin_unlock(lock: &o2hb_live_lock);
836
837	if (queued)
838	o2hb_run_event_list(queued_event: &event);
839
840	o2nm_node_put(node);
841	}
842
843	static void o2hb_set_quorum_device(struct o2hb_region *reg)
844	{
845	if (!o2hb_global_heartbeat_active())
846	return;
847
848	/* Prevent race with o2hb_heartbeat_group_drop_item() */
849	if (kthread_should_stop())
850	return;
851
852	/* Tag region as quorum only after thread reaches steady state */
853	if (atomic_read(v: &reg->hr_steady_iterations) != 0)
854	return;
855
856	spin_lock(lock: &o2hb_live_lock);
857
858	if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
859	goto unlock;
860
861	/*
862	* A region can be added to the quorum only when it sees all
863	* live nodes heartbeat on it. In other words, the region has been
864	* added to all nodes.
865	*/
866	if (!bitmap_equal(src1: reg->hr_live_node_bitmap, src2: o2hb_live_node_bitmap,
867	O2NM_MAX_NODES))
868	goto unlock;
869
870	printk(KERN_NOTICE "o2hb: Region %s (%pg) is now a quorum device\n",
871	config_item_name(&reg->hr_item), reg_bdev(reg));
872
873	set_bit(nr: reg->hr_region_num, addr: o2hb_quorum_region_bitmap);
874
875	/*
876	* If global heartbeat active, unpin all regions if the
877	* region count > CUT_OFF
878	*/
879	if (bitmap_weight(src: o2hb_quorum_region_bitmap,
880	O2NM_MAX_REGIONS) > O2HB_PIN_CUT_OFF)
881	o2hb_region_unpin(NULL);
882	unlock:
883	spin_unlock(lock: &o2hb_live_lock);
884	}
885
886	static int o2hb_check_slot(struct o2hb_region *reg,
887	struct o2hb_disk_slot *slot)
888	{
889	int changed = 0, gen_changed = 0;
890	struct o2hb_node_event event =
891	{ .hn_item = LIST_HEAD_INIT(event.hn_item), };
892	struct o2nm_node *node;
893	struct o2hb_disk_heartbeat_block *hb_block = reg->hr_tmp_block;
894	u64 cputime;
895	unsigned int dead_ms = o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS;
896	unsigned int slot_dead_ms;
897	int tmp;
898	int queued = 0;
899
900	memcpy(hb_block, slot->ds_raw_block, reg->hr_block_bytes);
901
902	/*
903	* If a node is no longer configured but is still in the livemap, we
904	* may need to clear that bit from the livemap.
905	*/
906	node = o2nm_get_node_by_num(node_num: slot->ds_node_num);
907	if (!node) {
908	spin_lock(lock: &o2hb_live_lock);
909	tmp = test_bit(slot->ds_node_num, o2hb_live_node_bitmap);
910	spin_unlock(lock: &o2hb_live_lock);
911	if (!tmp)
912	return 0;
913	}
914
915	if (!o2hb_verify_crc(reg, hb_block)) {
916	/* all paths from here will drop o2hb_live_lock for
917	* us. */
918	spin_lock(lock: &o2hb_live_lock);
919
920	/* Don't print an error on the console in this case -
921	* a freshly formatted heartbeat area will not have a
922	* crc set on it. */
923	if (list_empty(head: &slot->ds_live_item))
924	goto out;
925
926	/* The node is live but pushed out a bad crc. We
927	* consider it a transient miss but don't populate any
928	* other values as they may be junk. */
929	mlog(ML_ERROR, "Node %d has written a bad crc to %pg\n",
930	slot->ds_node_num, reg_bdev(reg));
931	o2hb_dump_slot(hb_block);
932
933	slot->ds_equal_samples++;
934	goto fire_callbacks;
935	}
936
937	/* we don't care if these wrap.. the state transitions below
938	* clear at the right places */
939	cputime = le64_to_cpu(hb_block->hb_seq);
940	if (slot->ds_last_time != cputime)
941	slot->ds_changed_samples++;
942	else
943	slot->ds_equal_samples++;
944	slot->ds_last_time = cputime;
945
946	/* The node changed heartbeat generations. We assume this to
947	* mean it dropped off but came back before we timed out. We
948	* want to consider it down for the time being but don't want
949	* to lose any changed_samples state we might build up to
950	* considering it live again. */
951	if (slot->ds_last_generation != le64_to_cpu(hb_block->hb_generation)) {
952	gen_changed = 1;
953	slot->ds_equal_samples = 0;
954	mlog(ML_HEARTBEAT, "Node %d changed generation (0x%llx "
955	"to 0x%llx)\n", slot->ds_node_num,
956	(long long)slot->ds_last_generation,
957	(long long)le64_to_cpu(hb_block->hb_generation));
958	}
959
960	slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
961
962	mlog(ML_HEARTBEAT, "Slot %d gen 0x%llx cksum 0x%x "
963	"seq %llu last %llu changed %u equal %u\n",
964	slot->ds_node_num, (long long)slot->ds_last_generation,
965	le32_to_cpu(hb_block->hb_cksum),
966	(unsigned long long)le64_to_cpu(hb_block->hb_seq),
967	(unsigned long long)slot->ds_last_time, slot->ds_changed_samples,
968	slot->ds_equal_samples);
969
970	spin_lock(lock: &o2hb_live_lock);
971
972	fire_callbacks:
973	/* dead nodes only come to life after some number of
974	* changes at any time during their dead time */
975	if (list_empty(head: &slot->ds_live_item) &&
976	slot->ds_changed_samples >= O2HB_LIVE_THRESHOLD) {
977	mlog(ML_HEARTBEAT, "Node %d (id 0x%llx) joined my region\n",
978	slot->ds_node_num, (long long)slot->ds_last_generation);
979
980	set_bit(nr: slot->ds_node_num, addr: reg->hr_live_node_bitmap);
981
982	/* first on the list generates a callback */
983	if (list_empty(head: &o2hb_live_slots[slot->ds_node_num])) {
984	mlog(ML_HEARTBEAT, "o2hb: Add node %d to live nodes "
985	"bitmap\n", slot->ds_node_num);
986	set_bit(nr: slot->ds_node_num, addr: o2hb_live_node_bitmap);
987
988	o2hb_queue_node_event(event: &event, type: O2HB_NODE_UP_CB, node,
989	node_num: slot->ds_node_num);
990
991	changed = 1;
992	queued = 1;
993	}
994
995	list_add_tail(new: &slot->ds_live_item,
996	head: &o2hb_live_slots[slot->ds_node_num]);
997
998	slot->ds_equal_samples = 0;
999
1000	/* We want to be sure that all nodes agree on the
1001	* number of milliseconds before a node will be
1002	* considered dead. The self-fencing timeout is
1003	* computed from this value, and a discrepancy might
1004	* result in heartbeat calling a node dead when it
1005	* hasn't self-fenced yet. */
1006	slot_dead_ms = le32_to_cpu(hb_block->hb_dead_ms);
1007	if (slot_dead_ms && slot_dead_ms != dead_ms) {
1008	/* TODO: Perhaps we can fail the region here. */
1009	mlog(ML_ERROR, "Node %d on device %pg has a dead count "
1010	"of %u ms, but our count is %u ms.\n"
1011	"Please double check your configuration values "
1012	"for 'O2CB_HEARTBEAT_THRESHOLD'\n",
1013	slot->ds_node_num, reg_bdev(reg),
1014	slot_dead_ms, dead_ms);
1015	}
1016	goto out;
1017	}
1018
1019	/* if the list is dead, we're done.. */
1020	if (list_empty(head: &slot->ds_live_item))
1021	goto out;
1022
1023	/* live nodes only go dead after enough consequtive missed
1024	* samples.. reset the missed counter whenever we see
1025	* activity */
1026	if (slot->ds_equal_samples >= o2hb_dead_threshold || gen_changed) {
1027	mlog(ML_HEARTBEAT, "Node %d left my region\n",
1028	slot->ds_node_num);
1029
1030	clear_bit(nr: slot->ds_node_num, addr: reg->hr_live_node_bitmap);
1031
1032	/* last off the live_slot generates a callback */
1033	list_del_init(entry: &slot->ds_live_item);
1034	if (list_empty(head: &o2hb_live_slots[slot->ds_node_num])) {
1035	mlog(ML_HEARTBEAT, "o2hb: Remove node %d from live "
1036	"nodes bitmap\n", slot->ds_node_num);
1037	clear_bit(nr: slot->ds_node_num, addr: o2hb_live_node_bitmap);
1038
1039	/* node can be null */
1040	o2hb_queue_node_event(event: &event, type: O2HB_NODE_DOWN_CB,
1041	node, node_num: slot->ds_node_num);
1042
1043	changed = 1;
1044	queued = 1;
1045	}
1046
1047	/* We don't clear this because the node is still
1048	* actually writing new blocks. */
1049	if (!gen_changed)
1050	slot->ds_changed_samples = 0;
1051	goto out;
1052	}
1053	if (slot->ds_changed_samples) {
1054	slot->ds_changed_samples = 0;
1055	slot->ds_equal_samples = 0;
1056	}
1057	out:
1058	spin_unlock(lock: &o2hb_live_lock);
1059
1060	if (queued)
1061	o2hb_run_event_list(queued_event: &event);
1062
1063	if (node)
1064	o2nm_node_put(node);
1065	return changed;
1066	}
1067
1068	static int o2hb_highest_node(unsigned long *nodes, int numbits)
1069	{
1070	return find_last_bit(addr: nodes, size: numbits);
1071	}
1072
1073	static int o2hb_lowest_node(unsigned long *nodes, int numbits)
1074	{
1075	return find_first_bit(addr: nodes, size: numbits);
1076	}
1077
1078	static int o2hb_do_disk_heartbeat(struct o2hb_region *reg)
1079	{
1080	int i, ret, highest_node, lowest_node;
1081	int membership_change = 0, own_slot_ok = 0;
1082	unsigned long configured_nodes[BITS_TO_LONGS(O2NM_MAX_NODES)];
1083	unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
1084	struct o2hb_bio_wait_ctxt write_wc;
1085
1086	ret = o2nm_configured_node_map(map: configured_nodes,
1087	bytes: sizeof(configured_nodes));
1088	if (ret) {
1089	mlog_errno(ret);
1090	goto bail;
1091	}
1092
1093	/*
1094	* If a node is not configured but is in the livemap, we still need
1095	* to read the slot so as to be able to remove it from the livemap.
1096	*/
1097	o2hb_fill_node_map(map: live_node_bitmap, O2NM_MAX_NODES);
1098	i = -1;
1099	while ((i = find_next_bit(addr: live_node_bitmap,
1100	O2NM_MAX_NODES, offset: i + 1)) < O2NM_MAX_NODES) {
1101	set_bit(nr: i, addr: configured_nodes);
1102	}
1103
1104	highest_node = o2hb_highest_node(nodes: configured_nodes, O2NM_MAX_NODES);
1105	lowest_node = o2hb_lowest_node(nodes: configured_nodes, O2NM_MAX_NODES);
1106	if (highest_node >= O2NM_MAX_NODES || lowest_node >= O2NM_MAX_NODES) {
1107	mlog(ML_NOTICE, "o2hb: No configured nodes found!\n");
1108	ret = -EINVAL;
1109	goto bail;
1110	}
1111
1112	/* No sense in reading the slots of nodes that don't exist
1113	* yet. Of course, if the node definitions have holes in them
1114	* then we're reading an empty slot anyway... Consider this
1115	* best-effort. */
1116	ret = o2hb_read_slots(reg, begin_slot: lowest_node, max_slots: highest_node + 1);
1117	if (ret < 0) {
1118	mlog_errno(ret);
1119	goto bail;
1120	}
1121
1122	/* With an up to date view of the slots, we can check that no
1123	* other node has been improperly configured to heartbeat in
1124	* our slot. */
1125	own_slot_ok = o2hb_check_own_slot(reg);
1126
1127	/* fill in the proper info for our next heartbeat */
1128	o2hb_prepare_block(reg, generation: reg->hr_generation);
1129
1130	ret = o2hb_issue_node_write(reg, write_wc: &write_wc);
1131	if (ret < 0) {
1132	mlog_errno(ret);
1133	goto bail;
1134	}
1135
1136	i = -1;
1137	while((i = find_next_bit(addr: configured_nodes,
1138	O2NM_MAX_NODES, offset: i + 1)) < O2NM_MAX_NODES) {
1139	membership_change |= o2hb_check_slot(reg, slot: &reg->hr_slots[i]);
1140	}
1141
1142	/*
1143	* We have to be sure we've advertised ourselves on disk
1144	* before we can go to steady state. This ensures that
1145	* people we find in our steady state have seen us.
1146	*/
1147	o2hb_wait_on_io(wc: &write_wc);
1148	if (write_wc.wc_error) {
1149	/* Do not re-arm the write timeout on I/O error - we
1150	* can't be sure that the new block ever made it to
1151	* disk */
1152	mlog(ML_ERROR, "Write error %d on device \"%pg\"\n",
1153	write_wc.wc_error, reg_bdev(reg));
1154	ret = write_wc.wc_error;
1155	goto bail;
1156	}
1157
1158	/* Skip disarming the timeout if own slot has stale/bad data */
1159	if (own_slot_ok) {
1160	o2hb_set_quorum_device(reg);
1161	o2hb_arm_timeout(reg);
1162	reg->hr_last_timeout_start = jiffies;
1163	}
1164
1165	bail:
1166	/* let the person who launched us know when things are steady */
1167	if (atomic_read(v: &reg->hr_steady_iterations) != 0) {
1168	if (!ret && own_slot_ok && !membership_change) {
1169	if (atomic_dec_and_test(v: &reg->hr_steady_iterations))
1170	wake_up(&o2hb_steady_queue);
1171	}
1172	}
1173
1174	if (atomic_read(v: &reg->hr_steady_iterations) != 0) {
1175	if (atomic_dec_and_test(v: &reg->hr_unsteady_iterations)) {
1176	printk(KERN_NOTICE "o2hb: Unable to stabilize "
1177	"heartbeat on region %s (%pg)\n",
1178	config_item_name(&reg->hr_item),
1179	reg_bdev(reg));
1180	atomic_set(v: &reg->hr_steady_iterations, i: 0);
1181	reg->hr_aborted_start = 1;
1182	wake_up(&o2hb_steady_queue);
1183	ret = -EIO;
1184	}
1185	}
1186
1187	return ret;
1188	}
1189
1190	/*
1191	* we ride the region ref that the region dir holds. before the region
1192	* dir is removed and drops it ref it will wait to tear down this
1193	* thread.
1194	*/
1195	static int o2hb_thread(void *data)
1196	{
1197	int i, ret;
1198	struct o2hb_region *reg = data;
1199	struct o2hb_bio_wait_ctxt write_wc;
1200	ktime_t before_hb, after_hb;
1201	unsigned int elapsed_msec;
1202
1203	mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n");
1204
1205	set_user_nice(current, MIN_NICE);
1206
1207	/* Pin node */
1208	ret = o2nm_depend_this_node();
1209	if (ret) {
1210	mlog(ML_ERROR, "Node has been deleted, ret = %d\n", ret);
1211	reg->hr_node_deleted = 1;
1212	wake_up(&o2hb_steady_queue);
1213	return 0;
1214	}
1215
1216	while (!kthread_should_stop() &&
1217	!reg->hr_unclean_stop && !reg->hr_aborted_start) {
1218	/* We track the time spent inside
1219	* o2hb_do_disk_heartbeat so that we avoid more than
1220	* hr_timeout_ms between disk writes. On busy systems
1221	* this should result in a heartbeat which is less
1222	* likely to time itself out. */
1223	before_hb = ktime_get_real();
1224
1225	ret = o2hb_do_disk_heartbeat(reg);
1226	reg->hr_last_hb_status = ret;
1227
1228	after_hb = ktime_get_real();
1229
1230	elapsed_msec = (unsigned int)
1231	ktime_ms_delta(later: after_hb, earlier: before_hb);
1232
1233	mlog(ML_HEARTBEAT,
1234	"start = %lld, end = %lld, msec = %u, ret = %d\n",
1235	before_hb, after_hb, elapsed_msec, ret);
1236
1237	if (!kthread_should_stop() &&
1238	elapsed_msec < reg->hr_timeout_ms) {
1239	/* the kthread api has blocked signals for us so no
1240	* need to record the return value. */
1241	msleep_interruptible(msecs: reg->hr_timeout_ms - elapsed_msec);
1242	}
1243	}
1244
1245	o2hb_disarm_timeout(reg);
1246
1247	/* unclean stop is only used in very bad situation */
1248	for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
1249	o2hb_shutdown_slot(slot: &reg->hr_slots[i]);
1250
1251	/* Explicit down notification - avoid forcing the other nodes
1252	* to timeout on this region when we could just as easily
1253	* write a clear generation - thus indicating to them that
1254	* this node has left this region.
1255	*/
1256	if (!reg->hr_unclean_stop && !reg->hr_aborted_start) {
1257	o2hb_prepare_block(reg, generation: 0);
1258	ret = o2hb_issue_node_write(reg, write_wc: &write_wc);
1259	if (ret == 0)
1260	o2hb_wait_on_io(wc: &write_wc);
1261	else
1262	mlog_errno(ret);
1263	}
1264
1265	/* Unpin node */
1266	o2nm_undepend_this_node();
1267
1268	mlog(ML_HEARTBEAT|ML_KTHREAD, "o2hb thread exiting\n");
1269
1270	return 0;
1271	}
1272
1273	#ifdef CONFIG_DEBUG_FS
1274	static int o2hb_debug_open(struct inode *inode, struct file *file)
1275	{
1276	struct o2hb_debug_buf *db = inode->i_private;
1277	struct o2hb_region *reg;
1278	unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1279	unsigned long lts;
1280	char *buf = NULL;
1281	int i = -1;
1282	int out = 0;
1283
1284	/* max_nodes should be the largest bitmap we pass here */
1285	BUG_ON(sizeof(map) < db->db_size);
1286
1287	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1288	if (!buf)
1289	goto bail;
1290
1291	switch (db->db_type) {
1292	case O2HB_DB_TYPE_LIVENODES:
1293	case O2HB_DB_TYPE_LIVEREGIONS:
1294	case O2HB_DB_TYPE_QUORUMREGIONS:
1295	case O2HB_DB_TYPE_FAILEDREGIONS:
1296	spin_lock(lock: &o2hb_live_lock);
1297	memcpy(map, db->db_data, db->db_size);
1298	spin_unlock(lock: &o2hb_live_lock);
1299	break;
1300
1301	case O2HB_DB_TYPE_REGION_LIVENODES:
1302	spin_lock(lock: &o2hb_live_lock);
1303	reg = (struct o2hb_region *)db->db_data;
1304	memcpy(map, reg->hr_live_node_bitmap, db->db_size);
1305	spin_unlock(lock: &o2hb_live_lock);
1306	break;
1307
1308	case O2HB_DB_TYPE_REGION_NUMBER:
1309	reg = (struct o2hb_region *)db->db_data;
1310	out += scnprintf(buf: buf + out, PAGE_SIZE - out, fmt: "%d\n",
1311	reg->hr_region_num);
1312	goto done;
1313
1314	case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
1315	reg = (struct o2hb_region *)db->db_data;
1316	lts = reg->hr_last_timeout_start;
1317	/* If 0, it has never been set before */
1318	if (lts)
1319	lts = jiffies_to_msecs(j: jiffies - lts);
1320	out += scnprintf(buf: buf + out, PAGE_SIZE - out, fmt: "%lu\n", lts);
1321	goto done;
1322
1323	case O2HB_DB_TYPE_REGION_PINNED:
1324	reg = (struct o2hb_region *)db->db_data;
1325	out += scnprintf(buf: buf + out, PAGE_SIZE - out, fmt: "%u\n",
1326	!!reg->hr_item_pinned);
1327	goto done;
1328
1329	default:
1330	goto done;
1331	}
1332
1333	while ((i = find_next_bit(addr: map, size: db->db_len, offset: i + 1)) < db->db_len)
1334	out += scnprintf(buf: buf + out, PAGE_SIZE - out, fmt: "%d ", i);
1335	out += scnprintf(buf: buf + out, PAGE_SIZE - out, fmt: "\n");
1336
1337	done:
1338	i_size_write(inode, i_size: out);
1339
1340	file->private_data = buf;
1341
1342	return 0;
1343	bail:
1344	return -ENOMEM;
1345	}
1346
1347	static int o2hb_debug_release(struct inode *inode, struct file *file)
1348	{
1349	kfree(objp: file->private_data);
1350	return 0;
1351	}
1352
1353	static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1354	size_t nbytes, loff_t *ppos)
1355	{
1356	return simple_read_from_buffer(to: buf, count: nbytes, ppos, from: file->private_data,
1357	available: i_size_read(inode: file->f_mapping->host));
1358	}
1359	#else
1360	static int o2hb_debug_open(struct inode *inode, struct file *file)
1361	{
1362	return 0;
1363	}
1364	static int o2hb_debug_release(struct inode *inode, struct file *file)
1365	{
1366	return 0;
1367	}
1368	static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1369	size_t nbytes, loff_t *ppos)
1370	{
1371	return 0;
1372	}
1373	#endif /* CONFIG_DEBUG_FS */
1374
1375	static const struct file_operations o2hb_debug_fops = {
1376	.open = o2hb_debug_open,
1377	.release = o2hb_debug_release,
1378	.read = o2hb_debug_read,
1379	.llseek = generic_file_llseek,
1380	};
1381
1382	void o2hb_exit(void)
1383	{
1384	debugfs_remove_recursive(dentry: o2hb_debug_dir);
1385	kfree(objp: o2hb_db_livenodes);
1386	kfree(objp: o2hb_db_liveregions);
1387	kfree(objp: o2hb_db_quorumregions);
1388	kfree(objp: o2hb_db_failedregions);
1389	}
1390
1391	static void o2hb_debug_create(const char *name, struct dentry *dir,
1392	struct o2hb_debug_buf **db, int db_len, int type,
1393	int size, int len, void *data)
1394	{
1395	*db = kmalloc(size: db_len, GFP_KERNEL);
1396	if (!*db)
1397	return;
1398
1399	(*db)->db_type = type;
1400	(*db)->db_size = size;
1401	(*db)->db_len = len;
1402	(*db)->db_data = data;
1403
1404	debugfs_create_file(name, S_IFREG|S_IRUSR, parent: dir, data: *db, fops: &o2hb_debug_fops);
1405	}
1406
1407	static void o2hb_debug_init(void)
1408	{
1409	o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
1410
1411	o2hb_debug_create(O2HB_DEBUG_LIVENODES, dir: o2hb_debug_dir,
1412	db: &o2hb_db_livenodes, db_len: sizeof(*o2hb_db_livenodes),
1413	O2HB_DB_TYPE_LIVENODES, size: sizeof(o2hb_live_node_bitmap),
1414	O2NM_MAX_NODES, data: o2hb_live_node_bitmap);
1415
1416	o2hb_debug_create(O2HB_DEBUG_LIVEREGIONS, dir: o2hb_debug_dir,
1417	db: &o2hb_db_liveregions, db_len: sizeof(*o2hb_db_liveregions),
1418	O2HB_DB_TYPE_LIVEREGIONS,
1419	size: sizeof(o2hb_live_region_bitmap), O2NM_MAX_REGIONS,
1420	data: o2hb_live_region_bitmap);
1421
1422	o2hb_debug_create(O2HB_DEBUG_QUORUMREGIONS, dir: o2hb_debug_dir,
1423	db: &o2hb_db_quorumregions,
1424	db_len: sizeof(*o2hb_db_quorumregions),
1425	O2HB_DB_TYPE_QUORUMREGIONS,
1426	size: sizeof(o2hb_quorum_region_bitmap), O2NM_MAX_REGIONS,
1427	data: o2hb_quorum_region_bitmap);
1428
1429	o2hb_debug_create(O2HB_DEBUG_FAILEDREGIONS, dir: o2hb_debug_dir,
1430	db: &o2hb_db_failedregions,
1431	db_len: sizeof(*o2hb_db_failedregions),
1432	O2HB_DB_TYPE_FAILEDREGIONS,
1433	size: sizeof(o2hb_failed_region_bitmap), O2NM_MAX_REGIONS,
1434	data: o2hb_failed_region_bitmap);
1435	}
1436
1437	void o2hb_init(void)
1438	{
1439	int i;
1440
1441	for (i = 0; i < ARRAY_SIZE(o2hb_callbacks); i++)
1442	INIT_LIST_HEAD(list: &o2hb_callbacks[i].list);
1443
1444	for (i = 0; i < ARRAY_SIZE(o2hb_live_slots); i++)
1445	INIT_LIST_HEAD(list: &o2hb_live_slots[i]);
1446
1447	bitmap_zero(dst: o2hb_live_node_bitmap, O2NM_MAX_NODES);
1448	bitmap_zero(dst: o2hb_region_bitmap, O2NM_MAX_REGIONS);
1449	bitmap_zero(dst: o2hb_live_region_bitmap, O2NM_MAX_REGIONS);
1450	bitmap_zero(dst: o2hb_quorum_region_bitmap, O2NM_MAX_REGIONS);
1451	bitmap_zero(dst: o2hb_failed_region_bitmap, O2NM_MAX_REGIONS);
1452
1453	o2hb_dependent_users = 0;
1454
1455	o2hb_debug_init();
1456	}
1457
1458	/* if we're already in a callback then we're already serialized by the sem */
1459	static void o2hb_fill_node_map_from_callback(unsigned long *map,
1460	unsigned int bits)
1461	{
1462	bitmap_copy(dst: map, src: o2hb_live_node_bitmap, nbits: bits);
1463	}
1464
1465	/*
1466	* get a map of all nodes that are heartbeating in any regions
1467	*/
1468	void o2hb_fill_node_map(unsigned long *map, unsigned int bits)
1469	{
1470	/* callers want to serialize this map and callbacks so that they
1471	* can trust that they don't miss nodes coming to the party */
1472	down_read(sem: &o2hb_callback_sem);
1473	spin_lock(lock: &o2hb_live_lock);
1474	o2hb_fill_node_map_from_callback(map, bits);
1475	spin_unlock(lock: &o2hb_live_lock);
1476	up_read(sem: &o2hb_callback_sem);
1477	}
1478	EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
1479
1480	/*
1481	* heartbeat configfs bits. The heartbeat set is a default set under
1482	* the cluster set in nodemanager.c.
1483	*/
1484
1485	static struct o2hb_region *to_o2hb_region(struct config_item *item)
1486	{
1487	return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
1488	}
1489
1490	/* drop_item only drops its ref after killing the thread, nothing should
1491	* be using the region anymore. this has to clean up any state that
1492	* attributes might have built up. */
1493	static void o2hb_region_release(struct config_item *item)
1494	{
1495	int i;
1496	struct page *page;
1497	struct o2hb_region *reg = to_o2hb_region(item);
1498
1499	mlog(ML_HEARTBEAT, "hb region release (%pg)\n", reg_bdev(reg));
1500
1501	kfree(objp: reg->hr_tmp_block);
1502
1503	if (reg->hr_slot_data) {
1504	for (i = 0; i < reg->hr_num_pages; i++) {
1505	page = reg->hr_slot_data[i];
1506	if (page)
1507	__free_page(page);
1508	}
1509	kfree(objp: reg->hr_slot_data);
1510	}
1511
1512	if (reg->hr_bdev_file)
1513	fput(reg->hr_bdev_file);
1514
1515	kfree(objp: reg->hr_slots);
1516
1517	debugfs_remove_recursive(dentry: reg->hr_debug_dir);
1518	kfree(objp: reg->hr_db_livenodes);
1519	kfree(objp: reg->hr_db_regnum);
1520	kfree(objp: reg->hr_db_elapsed_time);
1521	kfree(objp: reg->hr_db_pinned);
1522
1523	spin_lock(lock: &o2hb_live_lock);
1524	list_del(entry: &reg->hr_all_item);
1525	spin_unlock(lock: &o2hb_live_lock);
1526
1527	o2net_unregister_handler_list(list: &reg->hr_handler_list);
1528	kfree(objp: reg);
1529	}
1530
1531	static int o2hb_read_block_input(struct o2hb_region *reg,
1532	const char *page,
1533	unsigned long *ret_bytes,
1534	unsigned int *ret_bits)
1535	{
1536	unsigned long bytes;
1537	char *p = (char *)page;
1538
1539	bytes = simple_strtoul(p, &p, 0);
1540	if (!p || (*p && (*p != '\n')))
1541	return -EINVAL;
1542
1543	/* Heartbeat and fs min / max block sizes are the same. */
1544	if (bytes > 4096 || bytes < 512)
1545	return -ERANGE;
1546	if (hweight16(bytes) != 1)
1547	return -EINVAL;
1548
1549	if (ret_bytes)
1550	*ret_bytes = bytes;
1551	if (ret_bits)
1552	*ret_bits = ffs(bytes) - 1;
1553
1554	return 0;
1555	}
1556
1557	static ssize_t o2hb_region_block_bytes_show(struct config_item *item,
1558	char *page)
1559	{
1560	return sprintf(buf: page, fmt: "%u\n", to_o2hb_region(item)->hr_block_bytes);
1561	}
1562
1563	static ssize_t o2hb_region_block_bytes_store(struct config_item *item,
1564	const char *page,
1565	size_t count)
1566	{
1567	struct o2hb_region *reg = to_o2hb_region(item);
1568	int status;
1569	unsigned long block_bytes;
1570	unsigned int block_bits;
1571
1572	if (reg->hr_bdev_file)
1573	return -EINVAL;
1574
1575	status = o2hb_read_block_input(reg, page, ret_bytes: &block_bytes,
1576	ret_bits: &block_bits);
1577	if (status)
1578	return status;
1579
1580	reg->hr_block_bytes = (unsigned int)block_bytes;
1581	reg->hr_block_bits = block_bits;
1582
1583	return count;
1584	}
1585
1586	static ssize_t o2hb_region_start_block_show(struct config_item *item,
1587	char *page)
1588	{
1589	return sprintf(buf: page, fmt: "%llu\n", to_o2hb_region(item)->hr_start_block);
1590	}
1591
1592	static ssize_t o2hb_region_start_block_store(struct config_item *item,
1593	const char *page,
1594	size_t count)
1595	{
1596	struct o2hb_region *reg = to_o2hb_region(item);
1597	unsigned long long tmp;
1598	char *p = (char *)page;
1599	ssize_t ret;
1600
1601	if (reg->hr_bdev_file)
1602	return -EINVAL;
1603
1604	ret = kstrtoull(s: p, base: 0, res: &tmp);
1605	if (ret)
1606	return -EINVAL;
1607
1608	reg->hr_start_block = tmp;
1609
1610	return count;
1611	}
1612
1613	static ssize_t o2hb_region_blocks_show(struct config_item *item, char *page)
1614	{
1615	return sprintf(buf: page, fmt: "%d\n", to_o2hb_region(item)->hr_blocks);
1616	}
1617
1618	static ssize_t o2hb_region_blocks_store(struct config_item *item,
1619	const char *page,
1620	size_t count)
1621	{
1622	struct o2hb_region *reg = to_o2hb_region(item);
1623	unsigned long tmp;
1624	char *p = (char *)page;
1625
1626	if (reg->hr_bdev_file)
1627	return -EINVAL;
1628
1629	tmp = simple_strtoul(p, &p, 0);
1630	if (!p || (*p && (*p != '\n')))
1631	return -EINVAL;
1632
1633	if (tmp > O2NM_MAX_NODES || tmp == 0)
1634	return -ERANGE;
1635
1636	reg->hr_blocks = (unsigned int)tmp;
1637
1638	return count;
1639	}
1640
1641	static ssize_t o2hb_region_dev_show(struct config_item *item, char *page)
1642	{
1643	unsigned int ret = 0;
1644
1645	if (to_o2hb_region(item)->hr_bdev_file)
1646	ret = sprintf(buf: page, fmt: "%pg\n", reg_bdev(reg: to_o2hb_region(item)));
1647
1648	return ret;
1649	}
1650
1651	static void o2hb_init_region_params(struct o2hb_region *reg)
1652	{
1653	reg->hr_slots_per_page = PAGE_SIZE >> reg->hr_block_bits;
1654	reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
1655
1656	mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
1657	reg->hr_start_block, reg->hr_blocks);
1658	mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
1659	reg->hr_block_bytes, reg->hr_block_bits);
1660	mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
1661	mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
1662	}
1663
1664	static int o2hb_map_slot_data(struct o2hb_region *reg)
1665	{
1666	int i, j;
1667	unsigned int last_slot;
1668	unsigned int spp = reg->hr_slots_per_page;
1669	struct page *page;
1670	char *raw;
1671	struct o2hb_disk_slot *slot;
1672
1673	reg->hr_tmp_block = kmalloc(size: reg->hr_block_bytes, GFP_KERNEL);
1674	if (reg->hr_tmp_block == NULL)
1675	return -ENOMEM;
1676
1677	reg->hr_slots = kcalloc(n: reg->hr_blocks,
1678	size: sizeof(struct o2hb_disk_slot), GFP_KERNEL);
1679	if (reg->hr_slots == NULL)
1680	return -ENOMEM;
1681
1682	for(i = 0; i < reg->hr_blocks; i++) {
1683	slot = &reg->hr_slots[i];
1684	slot->ds_node_num = i;
1685	INIT_LIST_HEAD(list: &slot->ds_live_item);
1686	slot->ds_raw_block = NULL;
1687	}
1688
1689	reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
1690	mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
1691	"at %u blocks per page\n",
1692	reg->hr_num_pages, reg->hr_blocks, spp);
1693
1694	reg->hr_slot_data = kcalloc(n: reg->hr_num_pages, size: sizeof(struct page *),
1695	GFP_KERNEL);
1696	if (!reg->hr_slot_data)
1697	return -ENOMEM;
1698
1699	for(i = 0; i < reg->hr_num_pages; i++) {
1700	page = alloc_page(GFP_KERNEL);
1701	if (!page)
1702	return -ENOMEM;
1703
1704	reg->hr_slot_data[i] = page;
1705
1706	last_slot = i * spp;
1707	raw = page_address(page);
1708	for (j = 0;
1709	(j < spp) && ((j + last_slot) < reg->hr_blocks);
1710	j++) {
1711	BUG_ON((j + last_slot) >= reg->hr_blocks);
1712
1713	slot = &reg->hr_slots[j + last_slot];
1714	slot->ds_raw_block =
1715	(struct o2hb_disk_heartbeat_block *) raw;
1716
1717	raw += reg->hr_block_bytes;
1718	}
1719	}
1720
1721	return 0;
1722	}
1723
1724	/* Read in all the slots available and populate the tracking
1725	* structures so that we can start with a baseline idea of what's
1726	* there. */
1727	static int o2hb_populate_slot_data(struct o2hb_region *reg)
1728	{
1729	int ret, i;
1730	struct o2hb_disk_slot *slot;
1731	struct o2hb_disk_heartbeat_block *hb_block;
1732
1733	ret = o2hb_read_slots(reg, begin_slot: 0, max_slots: reg->hr_blocks);
1734	if (ret)
1735	goto out;
1736
1737	/* We only want to get an idea of the values initially in each
1738	* slot, so we do no verification - o2hb_check_slot will
1739	* actually determine if each configured slot is valid and
1740	* whether any values have changed. */
1741	for(i = 0; i < reg->hr_blocks; i++) {
1742	slot = &reg->hr_slots[i];
1743	hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
1744
1745	/* Only fill the values that o2hb_check_slot uses to
1746	* determine changing slots */
1747	slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
1748	slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
1749	}
1750
1751	out:
1752	return ret;
1753	}
1754
1755	/*
1756	* this is acting as commit; we set up all of hr_bdev_file and hr_task or
1757	* nothing
1758	*/
1759	static ssize_t o2hb_region_dev_store(struct config_item *item,
1760	const char *page,
1761	size_t count)
1762	{
1763	struct o2hb_region *reg = to_o2hb_region(item);
1764	struct task_struct *hb_task;
1765	long fd;
1766	int sectsize;
1767	char *p = (char *)page;
1768	struct fd f;
1769	ssize_t ret = -EINVAL;
1770	int live_threshold;
1771
1772	if (reg->hr_bdev_file)
1773	goto out;
1774
1775	/* We can't heartbeat without having had our node number
1776	* configured yet. */
1777	if (o2nm_this_node() == O2NM_MAX_NODES)
1778	goto out;
1779
1780	fd = simple_strtol(p, &p, 0);
1781	if (!p || (*p && (*p != '\n')))
1782	goto out;
1783
1784	if (fd < 0 || fd >= INT_MAX)
1785	goto out;
1786
1787	f = fdget(fd);
1788	if (f.file == NULL)
1789	goto out;
1790
1791	if (reg->hr_blocks == 0 || reg->hr_start_block == 0 ||
1792	reg->hr_block_bytes == 0)
1793	goto out2;
1794
1795	if (!S_ISBLK(f.file->f_mapping->host->i_mode))
1796	goto out2;
1797
1798	reg->hr_bdev_file = bdev_file_open_by_dev(dev: f.file->f_mapping->host->i_rdev,
1799	BLK_OPEN_WRITE | BLK_OPEN_READ, NULL, NULL);
1800	if (IS_ERR(ptr: reg->hr_bdev_file)) {
1801	ret = PTR_ERR(ptr: reg->hr_bdev_file);
1802	reg->hr_bdev_file = NULL;
1803	goto out2;
1804	}
1805
1806	sectsize = bdev_logical_block_size(bdev: reg_bdev(reg));
1807	if (sectsize != reg->hr_block_bytes) {
1808	mlog(ML_ERROR,
1809	"blocksize %u incorrect for device, expected %d",
1810	reg->hr_block_bytes, sectsize);
1811	ret = -EINVAL;
1812	goto out3;
1813	}
1814
1815	o2hb_init_region_params(reg);
1816
1817	/* Generation of zero is invalid */
1818	do {
1819	get_random_bytes(buf: &reg->hr_generation,
1820	len: sizeof(reg->hr_generation));
1821	} while (reg->hr_generation == 0);
1822
1823	ret = o2hb_map_slot_data(reg);
1824	if (ret) {
1825	mlog_errno(ret);
1826	goto out3;
1827	}
1828
1829	ret = o2hb_populate_slot_data(reg);
1830	if (ret) {
1831	mlog_errno(ret);
1832	goto out3;
1833	}
1834
1835	INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
1836	INIT_DELAYED_WORK(&reg->hr_nego_timeout_work, o2hb_nego_timeout);
1837
1838	/*
1839	* A node is considered live after it has beat LIVE_THRESHOLD
1840	* times. We're not steady until we've given them a chance
1841	* _after_ our first read.
1842	* The default threshold is bare minimum so as to limit the delay
1843	* during mounts. For global heartbeat, the threshold doubled for the
1844	* first region.
1845	*/
1846	live_threshold = O2HB_LIVE_THRESHOLD;
1847	if (o2hb_global_heartbeat_active()) {
1848	spin_lock(lock: &o2hb_live_lock);
1849	if (bitmap_weight(src: o2hb_region_bitmap, O2NM_MAX_REGIONS) == 1)
1850	live_threshold <<= 1;
1851	spin_unlock(lock: &o2hb_live_lock);
1852	}
1853	++live_threshold;
1854	atomic_set(v: &reg->hr_steady_iterations, i: live_threshold);
1855	/* unsteady_iterations is triple the steady_iterations */
1856	atomic_set(v: &reg->hr_unsteady_iterations, i: (live_threshold * 3));
1857
1858	hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
1859	reg->hr_item.ci_name);
1860	if (IS_ERR(ptr: hb_task)) {
1861	ret = PTR_ERR(ptr: hb_task);
1862	mlog_errno(ret);
1863	goto out3;
1864	}
1865
1866	spin_lock(lock: &o2hb_live_lock);
1867	reg->hr_task = hb_task;
1868	spin_unlock(lock: &o2hb_live_lock);
1869
1870	ret = wait_event_interruptible(o2hb_steady_queue,
1871	atomic_read(&reg->hr_steady_iterations) == 0 ||
1872	reg->hr_node_deleted);
1873	if (ret) {
1874	atomic_set(v: &reg->hr_steady_iterations, i: 0);
1875	reg->hr_aborted_start = 1;
1876	}
1877
1878	if (reg->hr_aborted_start) {
1879	ret = -EIO;
1880	goto out3;
1881	}
1882
1883	if (reg->hr_node_deleted) {
1884	ret = -EINVAL;
1885	goto out3;
1886	}
1887
1888	/* Ok, we were woken. Make sure it wasn't by drop_item() */
1889	spin_lock(lock: &o2hb_live_lock);
1890	hb_task = reg->hr_task;
1891	if (o2hb_global_heartbeat_active())
1892	set_bit(nr: reg->hr_region_num, addr: o2hb_live_region_bitmap);
1893	spin_unlock(lock: &o2hb_live_lock);
1894
1895	if (hb_task)
1896	ret = count;
1897	else
1898	ret = -EIO;
1899
1900	if (hb_task && o2hb_global_heartbeat_active())
1901	printk(KERN_NOTICE "o2hb: Heartbeat started on region %s (%pg)\n",
1902	config_item_name(&reg->hr_item), reg_bdev(reg));
1903
1904	out3:
1905	if (ret < 0) {
1906	fput(reg->hr_bdev_file);
1907	reg->hr_bdev_file = NULL;
1908	}
1909	out2:
1910	fdput(fd: f);
1911	out:
1912	return ret;
1913	}
1914
1915	static ssize_t o2hb_region_pid_show(struct config_item *item, char *page)
1916	{
1917	struct o2hb_region *reg = to_o2hb_region(item);
1918	pid_t pid = 0;
1919
1920	spin_lock(lock: &o2hb_live_lock);
1921	if (reg->hr_task)
1922	pid = task_pid_nr(tsk: reg->hr_task);
1923	spin_unlock(lock: &o2hb_live_lock);
1924
1925	if (!pid)
1926	return 0;
1927
1928	return sprintf(buf: page, fmt: "%u\n", pid);
1929	}
1930
1931	CONFIGFS_ATTR(o2hb_region_, block_bytes);
1932	CONFIGFS_ATTR(o2hb_region_, start_block);
1933	CONFIGFS_ATTR(o2hb_region_, blocks);
1934	CONFIGFS_ATTR(o2hb_region_, dev);
1935	CONFIGFS_ATTR_RO(o2hb_region_, pid);
1936
1937	static struct configfs_attribute *o2hb_region_attrs[] = {
1938	&o2hb_region_attr_block_bytes,
1939	&o2hb_region_attr_start_block,
1940	&o2hb_region_attr_blocks,
1941	&o2hb_region_attr_dev,
1942	&o2hb_region_attr_pid,
1943	NULL,
1944	};
1945
1946	static struct configfs_item_operations o2hb_region_item_ops = {
1947	.release = o2hb_region_release,
1948	};
1949
1950	static const struct config_item_type o2hb_region_type = {
1951	.ct_item_ops = &o2hb_region_item_ops,
1952	.ct_attrs = o2hb_region_attrs,
1953	.ct_owner = THIS_MODULE,
1954	};
1955
1956	/* heartbeat set */
1957
1958	struct o2hb_heartbeat_group {
1959	struct config_group hs_group;
1960	/* some stuff? */
1961	};
1962
1963	static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
1964	{
1965	return group ?
1966	container_of(group, struct o2hb_heartbeat_group, hs_group)
1967	: NULL;
1968	}
1969
1970	static void o2hb_debug_region_init(struct o2hb_region *reg,
1971	struct dentry *parent)
1972	{
1973	struct dentry *dir;
1974
1975	dir = debugfs_create_dir(name: config_item_name(item: &reg->hr_item), parent);
1976	reg->hr_debug_dir = dir;
1977
1978	o2hb_debug_create(O2HB_DEBUG_LIVENODES, dir, db: &(reg->hr_db_livenodes),
1979	db_len: sizeof(*(reg->hr_db_livenodes)),
1980	O2HB_DB_TYPE_REGION_LIVENODES,
1981	size: sizeof(reg->hr_live_node_bitmap), O2NM_MAX_NODES,
1982	data: reg);
1983
1984	o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER, dir, db: &(reg->hr_db_regnum),
1985	db_len: sizeof(*(reg->hr_db_regnum)),
1986	O2HB_DB_TYPE_REGION_NUMBER, size: 0, O2NM_MAX_NODES, data: reg);
1987
1988	o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME, dir,
1989	db: &(reg->hr_db_elapsed_time),
1990	db_len: sizeof(*(reg->hr_db_elapsed_time)),
1991	O2HB_DB_TYPE_REGION_ELAPSED_TIME, size: 0, len: 0, data: reg);
1992
1993	o2hb_debug_create(O2HB_DEBUG_REGION_PINNED, dir, db: &(reg->hr_db_pinned),
1994	db_len: sizeof(*(reg->hr_db_pinned)),
1995	O2HB_DB_TYPE_REGION_PINNED, size: 0, len: 0, data: reg);
1996
1997	}
1998
1999	static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
2000	const char *name)
2001	{
2002	struct o2hb_region *reg = NULL;
2003	int ret;
2004
2005	reg = kzalloc(size: sizeof(struct o2hb_region), GFP_KERNEL);
2006	if (reg == NULL)
2007	return ERR_PTR(error: -ENOMEM);
2008
2009	if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
2010	ret = -ENAMETOOLONG;
2011	goto free;
2012	}
2013
2014	spin_lock(lock: &o2hb_live_lock);
2015	reg->hr_region_num = 0;
2016	if (o2hb_global_heartbeat_active()) {
2017	reg->hr_region_num = find_first_zero_bit(addr: o2hb_region_bitmap,
2018	O2NM_MAX_REGIONS);
2019	if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
2020	spin_unlock(lock: &o2hb_live_lock);
2021	ret = -EFBIG;
2022	goto free;
2023	}
2024	set_bit(nr: reg->hr_region_num, addr: o2hb_region_bitmap);
2025	}
2026	list_add_tail(new: &reg->hr_all_item, head: &o2hb_all_regions);
2027	spin_unlock(lock: &o2hb_live_lock);
2028
2029	config_item_init_type_name(item: &reg->hr_item, name, type: &o2hb_region_type);
2030
2031	/* this is the same way to generate msg key as dlm, for local heartbeat,
2032	* name is also the same, so make initial crc value different to avoid
2033	* message key conflict.
2034	*/
2035	reg->hr_key = crc32_le(crc: reg->hr_region_num + O2NM_MAX_REGIONS,
2036	p: name, strlen(name));
2037	INIT_LIST_HEAD(list: &reg->hr_handler_list);
2038	ret = o2net_register_handler(msg_type: O2HB_NEGO_TIMEOUT_MSG, key: reg->hr_key,
2039	max_len: sizeof(struct o2hb_nego_msg),
2040	func: o2hb_nego_timeout_handler,
2041	data: reg, NULL, unreg_list: &reg->hr_handler_list);
2042	if (ret)
2043	goto remove_item;
2044
2045	ret = o2net_register_handler(msg_type: O2HB_NEGO_APPROVE_MSG, key: reg->hr_key,
2046	max_len: sizeof(struct o2hb_nego_msg),
2047	func: o2hb_nego_approve_handler,
2048	data: reg, NULL, unreg_list: &reg->hr_handler_list);
2049	if (ret)
2050	goto unregister_handler;
2051
2052	o2hb_debug_region_init(reg, parent: o2hb_debug_dir);
2053
2054	return &reg->hr_item;
2055
2056	unregister_handler:
2057	o2net_unregister_handler_list(list: &reg->hr_handler_list);
2058	remove_item:
2059	spin_lock(lock: &o2hb_live_lock);
2060	list_del(entry: &reg->hr_all_item);
2061	if (o2hb_global_heartbeat_active())
2062	clear_bit(nr: reg->hr_region_num, addr: o2hb_region_bitmap);
2063	spin_unlock(lock: &o2hb_live_lock);
2064	free:
2065	kfree(objp: reg);
2066	return ERR_PTR(error: ret);
2067	}
2068
2069	static void o2hb_heartbeat_group_drop_item(struct config_group *group,
2070	struct config_item *item)
2071	{
2072	struct task_struct *hb_task;
2073	struct o2hb_region *reg = to_o2hb_region(item);
2074	int quorum_region = 0;
2075
2076	/* stop the thread when the user removes the region dir */
2077	spin_lock(lock: &o2hb_live_lock);
2078	hb_task = reg->hr_task;
2079	reg->hr_task = NULL;
2080	reg->hr_item_dropped = 1;
2081	spin_unlock(lock: &o2hb_live_lock);
2082
2083	if (hb_task)
2084	kthread_stop(k: hb_task);
2085
2086	if (o2hb_global_heartbeat_active()) {
2087	spin_lock(lock: &o2hb_live_lock);
2088	clear_bit(nr: reg->hr_region_num, addr: o2hb_region_bitmap);
2089	clear_bit(nr: reg->hr_region_num, addr: o2hb_live_region_bitmap);
2090	if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
2091	quorum_region = 1;
2092	clear_bit(nr: reg->hr_region_num, addr: o2hb_quorum_region_bitmap);
2093	spin_unlock(lock: &o2hb_live_lock);
2094	printk(KERN_NOTICE "o2hb: Heartbeat %s on region %s (%pg)\n",
2095	((atomic_read(&reg->hr_steady_iterations) == 0) ?
2096	"stopped" : "start aborted"), config_item_name(item),
2097	reg_bdev(reg));
2098	}
2099
2100	/*
2101	* If we're racing a dev_write(), we need to wake them. They will
2102	* check reg->hr_task
2103	*/
2104	if (atomic_read(v: &reg->hr_steady_iterations) != 0) {
2105	reg->hr_aborted_start = 1;
2106	atomic_set(v: &reg->hr_steady_iterations, i: 0);
2107	wake_up(&o2hb_steady_queue);
2108	}
2109
2110	config_item_put(item);
2111
2112	if (!o2hb_global_heartbeat_active() || !quorum_region)
2113	return;
2114
2115	/*
2116	* If global heartbeat active and there are dependent users,
2117	* pin all regions if quorum region count <= CUT_OFF
2118	*/
2119	spin_lock(lock: &o2hb_live_lock);
2120
2121	if (!o2hb_dependent_users)
2122	goto unlock;
2123
2124	if (bitmap_weight(src: o2hb_quorum_region_bitmap,
2125	O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2126	o2hb_region_pin(NULL);
2127
2128	unlock:
2129	spin_unlock(lock: &o2hb_live_lock);
2130	}
2131
2132	static ssize_t o2hb_heartbeat_group_dead_threshold_show(struct config_item *item,
2133	char *page)
2134	{
2135	return sprintf(buf: page, fmt: "%u\n", o2hb_dead_threshold);
2136	}
2137
2138	static ssize_t o2hb_heartbeat_group_dead_threshold_store(struct config_item *item,
2139	const char *page, size_t count)
2140	{
2141	unsigned long tmp;
2142	char *p = (char *)page;
2143
2144	tmp = simple_strtoul(p, &p, 10);
2145	if (!p || (*p && (*p != '\n')))
2146	return -EINVAL;
2147
2148	/* this will validate ranges for us. */
2149	o2hb_dead_threshold_set(threshold: (unsigned int) tmp);
2150
2151	return count;
2152	}
2153
2154	static ssize_t o2hb_heartbeat_group_mode_show(struct config_item *item,
2155	char *page)
2156	{
2157	return sprintf(buf: page, fmt: "%s\n",
2158	o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
2159	}
2160
2161	static ssize_t o2hb_heartbeat_group_mode_store(struct config_item *item,
2162	const char *page, size_t count)
2163	{
2164	unsigned int i;
2165	int ret;
2166	size_t len;
2167
2168	len = (page[count - 1] == '\n') ? count - 1 : count;
2169	if (!len)
2170	return -EINVAL;
2171
2172	for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
2173	if (strncasecmp(s1: page, s2: o2hb_heartbeat_mode_desc[i], n: len))
2174	continue;
2175
2176	ret = o2hb_global_heartbeat_mode_set(hb_mode: i);
2177	if (!ret)
2178	printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
2179	o2hb_heartbeat_mode_desc[i]);
2180	return count;
2181	}
2182
2183	return -EINVAL;
2184
2185	}
2186
2187	CONFIGFS_ATTR(o2hb_heartbeat_group_, dead_threshold);
2188	CONFIGFS_ATTR(o2hb_heartbeat_group_, mode);
2189
2190	static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
2191	&o2hb_heartbeat_group_attr_dead_threshold,
2192	&o2hb_heartbeat_group_attr_mode,
2193	NULL,
2194	};
2195
2196	static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
2197	.make_item = o2hb_heartbeat_group_make_item,
2198	.drop_item = o2hb_heartbeat_group_drop_item,
2199	};
2200
2201	static const struct config_item_type o2hb_heartbeat_group_type = {
2202	.ct_group_ops = &o2hb_heartbeat_group_group_ops,
2203	.ct_attrs = o2hb_heartbeat_group_attrs,
2204	.ct_owner = THIS_MODULE,
2205	};
2206
2207	/* this is just here to avoid touching group in heartbeat.h which the
2208	* entire damn world #includes */
2209	struct config_group *o2hb_alloc_hb_set(void)
2210	{
2211	struct o2hb_heartbeat_group *hs = NULL;
2212	struct config_group *ret = NULL;
2213
2214	hs = kzalloc(size: sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
2215	if (hs == NULL)
2216	goto out;
2217
2218	config_group_init_type_name(group: &hs->hs_group, name: "heartbeat",
2219	type: &o2hb_heartbeat_group_type);
2220
2221	ret = &hs->hs_group;
2222	out:
2223	if (ret == NULL)
2224	kfree(objp: hs);
2225	return ret;
2226	}
2227
2228	void o2hb_free_hb_set(struct config_group *group)
2229	{
2230	struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
2231	kfree(objp: hs);
2232	}
2233
2234	/* hb callback registration and issuing */
2235
2236	static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
2237	{
2238	if (type == O2HB_NUM_CB)
2239	return ERR_PTR(error: -EINVAL);
2240
2241	return &o2hb_callbacks[type];
2242	}
2243
2244	void o2hb_setup_callback(struct o2hb_callback_func *hc,
2245	enum o2hb_callback_type type,
2246	o2hb_cb_func *func,
2247	void *data,
2248	int priority)
2249	{
2250	INIT_LIST_HEAD(list: &hc->hc_item);
2251	hc->hc_func = func;
2252	hc->hc_data = data;
2253	hc->hc_priority = priority;
2254	hc->hc_type = type;
2255	hc->hc_magic = O2HB_CB_MAGIC;
2256	}
2257	EXPORT_SYMBOL_GPL(o2hb_setup_callback);
2258
2259	/*
2260	* In local heartbeat mode, region_uuid passed matches the dlm domain name.
2261	* In global heartbeat mode, region_uuid passed is NULL.
2262	*
2263	* In local, we only pin the matching region. In global we pin all the active
2264	* regions.
2265	*/
2266	static int o2hb_region_pin(const char *region_uuid)
2267	{
2268	int ret = 0, found = 0;
2269	struct o2hb_region *reg;
2270	char *uuid;
2271
2272	assert_spin_locked(&o2hb_live_lock);
2273
2274	list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2275	if (reg->hr_item_dropped)
2276	continue;
2277
2278	uuid = config_item_name(item: &reg->hr_item);
2279
2280	/* local heartbeat */
2281	if (region_uuid) {
2282	if (strcmp(region_uuid, uuid))
2283	continue;
2284	found = 1;
2285	}
2286
2287	if (reg->hr_item_pinned || reg->hr_item_dropped)
2288	goto skip_pin;
2289
2290	/* Ignore ENOENT only for local hb (userdlm domain) */
2291	ret = o2nm_depend_item(item: &reg->hr_item);
2292	if (!ret) {
2293	mlog(ML_CLUSTER, "Pin region %s\n", uuid);
2294	reg->hr_item_pinned = 1;
2295	} else {
2296	if (ret == -ENOENT && found)
2297	ret = 0;
2298	else {
2299	mlog(ML_ERROR, "Pin region %s fails with %d\n",
2300	uuid, ret);
2301	break;
2302	}
2303	}
2304	skip_pin:
2305	if (found)
2306	break;
2307	}
2308
2309	return ret;
2310	}
2311
2312	/*
2313	* In local heartbeat mode, region_uuid passed matches the dlm domain name.
2314	* In global heartbeat mode, region_uuid passed is NULL.
2315	*
2316	* In local, we only unpin the matching region. In global we unpin all the
2317	* active regions.
2318	*/
2319	static void o2hb_region_unpin(const char *region_uuid)
2320	{
2321	struct o2hb_region *reg;
2322	char *uuid;
2323	int found = 0;
2324
2325	assert_spin_locked(&o2hb_live_lock);
2326
2327	list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2328	if (reg->hr_item_dropped)
2329	continue;
2330
2331	uuid = config_item_name(item: &reg->hr_item);
2332	if (region_uuid) {
2333	if (strcmp(region_uuid, uuid))
2334	continue;
2335	found = 1;
2336	}
2337
2338	if (reg->hr_item_pinned) {
2339	mlog(ML_CLUSTER, "Unpin region %s\n", uuid);
2340	o2nm_undepend_item(item: &reg->hr_item);
2341	reg->hr_item_pinned = 0;
2342	}
2343	if (found)
2344	break;
2345	}
2346	}
2347
2348	static int o2hb_region_inc_user(const char *region_uuid)
2349	{
2350	int ret = 0;
2351
2352	spin_lock(lock: &o2hb_live_lock);
2353
2354	/* local heartbeat */
2355	if (!o2hb_global_heartbeat_active()) {
2356	ret = o2hb_region_pin(region_uuid);
2357	goto unlock;
2358	}
2359
2360	/*
2361	* if global heartbeat active and this is the first dependent user,
2362	* pin all regions if quorum region count <= CUT_OFF
2363	*/
2364	o2hb_dependent_users++;
2365	if (o2hb_dependent_users > 1)
2366	goto unlock;
2367
2368	if (bitmap_weight(src: o2hb_quorum_region_bitmap,
2369	O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2370	ret = o2hb_region_pin(NULL);
2371
2372	unlock:
2373	spin_unlock(lock: &o2hb_live_lock);
2374	return ret;
2375	}
2376
2377	static void o2hb_region_dec_user(const char *region_uuid)
2378	{
2379	spin_lock(lock: &o2hb_live_lock);
2380
2381	/* local heartbeat */
2382	if (!o2hb_global_heartbeat_active()) {
2383	o2hb_region_unpin(region_uuid);
2384	goto unlock;
2385	}
2386
2387	/*
2388	* if global heartbeat active and there are no dependent users,
2389	* unpin all quorum regions
2390	*/
2391	o2hb_dependent_users--;
2392	if (!o2hb_dependent_users)
2393	o2hb_region_unpin(NULL);
2394
2395	unlock:
2396	spin_unlock(lock: &o2hb_live_lock);
2397	}
2398
2399	int o2hb_register_callback(const char *region_uuid,
2400	struct o2hb_callback_func *hc)
2401	{
2402	struct o2hb_callback_func *f;
2403	struct o2hb_callback *hbcall;
2404	int ret;
2405
2406	BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2407	BUG_ON(!list_empty(&hc->hc_item));
2408
2409	hbcall = hbcall_from_type(type: hc->hc_type);
2410	if (IS_ERR(ptr: hbcall)) {
2411	ret = PTR_ERR(ptr: hbcall);
2412	goto out;
2413	}
2414
2415	if (region_uuid) {
2416	ret = o2hb_region_inc_user(region_uuid);
2417	if (ret) {
2418	mlog_errno(ret);
2419	goto out;
2420	}
2421	}
2422
2423	down_write(sem: &o2hb_callback_sem);
2424
2425	list_for_each_entry(f, &hbcall->list, hc_item) {
2426	if (hc->hc_priority < f->hc_priority) {
2427	list_add_tail(new: &hc->hc_item, head: &f->hc_item);
2428	break;
2429	}
2430	}
2431	if (list_empty(head: &hc->hc_item))
2432	list_add_tail(new: &hc->hc_item, head: &hbcall->list);
2433
2434	up_write(sem: &o2hb_callback_sem);
2435	ret = 0;
2436	out:
2437	mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
2438	ret, __builtin_return_address(0), hc);
2439	return ret;
2440	}
2441	EXPORT_SYMBOL_GPL(o2hb_register_callback);
2442
2443	void o2hb_unregister_callback(const char *region_uuid,
2444	struct o2hb_callback_func *hc)
2445	{
2446	BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2447
2448	mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
2449	__builtin_return_address(0), hc);
2450
2451	/* XXX Can this happen _with_ a region reference? */
2452	if (list_empty(head: &hc->hc_item))
2453	return;
2454
2455	if (region_uuid)
2456	o2hb_region_dec_user(region_uuid);
2457
2458	down_write(sem: &o2hb_callback_sem);
2459
2460	list_del_init(entry: &hc->hc_item);
2461
2462	up_write(sem: &o2hb_callback_sem);
2463	}
2464	EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
2465
2466	int o2hb_check_node_heartbeating_no_sem(u8 node_num)
2467	{
2468	unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2469
2470	spin_lock(lock: &o2hb_live_lock);
2471	o2hb_fill_node_map_from_callback(map: testing_map, O2NM_MAX_NODES);
2472	spin_unlock(lock: &o2hb_live_lock);
2473	if (!test_bit(node_num, testing_map)) {
2474	mlog(ML_HEARTBEAT,
2475	"node (%u) does not have heartbeating enabled.\n",
2476	node_num);
2477	return 0;
2478	}
2479
2480	return 1;
2481	}
2482	EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_no_sem);
2483
2484	int o2hb_check_node_heartbeating_from_callback(u8 node_num)
2485	{
2486	unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2487
2488	o2hb_fill_node_map_from_callback(map: testing_map, O2NM_MAX_NODES);
2489	if (!test_bit(node_num, testing_map)) {
2490	mlog(ML_HEARTBEAT,
2491	"node (%u) does not have heartbeating enabled.\n",
2492	node_num);
2493	return 0;
2494	}
2495
2496	return 1;
2497	}
2498	EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_from_callback);
2499
2500	/*
2501	* this is just a hack until we get the plumbing which flips file systems
2502	* read only and drops the hb ref instead of killing the node dead.
2503	*/
2504	void o2hb_stop_all_regions(void)
2505	{
2506	struct o2hb_region *reg;
2507
2508	mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");
2509
2510	spin_lock(lock: &o2hb_live_lock);
2511
2512	list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
2513	reg->hr_unclean_stop = 1;
2514
2515	spin_unlock(lock: &o2hb_live_lock);
2516	}
2517	EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
2518
2519	int o2hb_get_all_regions(char *region_uuids, u8 max_regions)
2520	{
2521	struct o2hb_region *reg;
2522	int numregs = 0;
2523	char *p;
2524
2525	spin_lock(lock: &o2hb_live_lock);
2526
2527	p = region_uuids;
2528	list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2529	if (reg->hr_item_dropped)
2530	continue;
2531
2532	mlog(0, "Region: %s\n", config_item_name(&reg->hr_item));
2533	if (numregs < max_regions) {
2534	memcpy(p, config_item_name(&reg->hr_item),
2535	O2HB_MAX_REGION_NAME_LEN);
2536	p += O2HB_MAX_REGION_NAME_LEN;
2537	}
2538	numregs++;
2539	}
2540
2541	spin_unlock(lock: &o2hb_live_lock);
2542
2543	return numregs;
2544	}
2545	EXPORT_SYMBOL_GPL(o2hb_get_all_regions);
2546
2547	int o2hb_global_heartbeat_active(void)
2548	{
2549	return (o2hb_heartbeat_mode == O2HB_HEARTBEAT_GLOBAL);
2550	}
2551	EXPORT_SYMBOL(o2hb_global_heartbeat_active);
2552