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