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TOMOYO Linux Cross Reference
Linux/fs/ocfs2/cluster/heartbeat.c

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  1 /* -*- mode: c; c-basic-offset: 8; -*-
  2  * vim: noexpandtab sw=8 ts=8 sts=0:
  3  *
  4  * Copyright (C) 2004, 2005 Oracle.  All rights reserved.
  5  *
  6  * This program is free software; you can redistribute it and/or
  7  * modify it under the terms of the GNU General Public
  8  * License as published by the Free Software Foundation; either
  9  * version 2 of the License, or (at your option) any later version.
 10  *
 11  * This program is distributed in the hope that it will be useful,
 12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 14  * General Public License for more details.
 15  *
 16  * You should have received a copy of the GNU General Public
 17  * License along with this program; if not, write to the
 18  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 19  * Boston, MA 021110-1307, USA.
 20  */
 21 
 22 #include <linux/kernel.h>
 23 #include <linux/sched.h>
 24 #include <linux/jiffies.h>
 25 #include <linux/module.h>
 26 #include <linux/fs.h>
 27 #include <linux/bio.h>
 28 #include <linux/blkdev.h>
 29 #include <linux/delay.h>
 30 #include <linux/file.h>
 31 #include <linux/kthread.h>
 32 #include <linux/configfs.h>
 33 #include <linux/random.h>
 34 #include <linux/crc32.h>
 35 #include <linux/time.h>
 36 #include <linux/debugfs.h>
 37 #include <linux/slab.h>
 38 #include <linux/bitmap.h>
 39 
 40 #include "heartbeat.h"
 41 #include "tcp.h"
 42 #include "nodemanager.h"
 43 #include "quorum.h"
 44 
 45 #include "masklog.h"
 46 
 47 
 48 /*
 49  * The first heartbeat pass had one global thread that would serialize all hb
 50  * callback calls.  This global serializing sem should only be removed once
 51  * we've made sure that all callees can deal with being called concurrently
 52  * from multiple hb region threads.
 53  */
 54 static DECLARE_RWSEM(o2hb_callback_sem);
 55 
 56 /*
 57  * multiple hb threads are watching multiple regions.  A node is live
 58  * whenever any of the threads sees activity from the node in its region.
 59  */
 60 static DEFINE_SPINLOCK(o2hb_live_lock);
 61 static struct list_head o2hb_live_slots[O2NM_MAX_NODES];
 62 static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 63 static LIST_HEAD(o2hb_node_events);
 64 static DECLARE_WAIT_QUEUE_HEAD(o2hb_steady_queue);
 65 
 66 /*
 67  * In global heartbeat, we maintain a series of region bitmaps.
 68  *      - o2hb_region_bitmap allows us to limit the region number to max region.
 69  *      - o2hb_live_region_bitmap tracks live regions (seen steady iterations).
 70  *      - o2hb_quorum_region_bitmap tracks live regions that have seen all nodes
 71  *              heartbeat on it.
 72  *      - o2hb_failed_region_bitmap tracks the regions that have seen io timeouts.
 73  */
 74 static unsigned long o2hb_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
 75 static unsigned long o2hb_live_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
 76 static unsigned long o2hb_quorum_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
 77 static unsigned long o2hb_failed_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
 78 
 79 #define O2HB_DB_TYPE_LIVENODES          0
 80 #define O2HB_DB_TYPE_LIVEREGIONS        1
 81 #define O2HB_DB_TYPE_QUORUMREGIONS      2
 82 #define O2HB_DB_TYPE_FAILEDREGIONS      3
 83 #define O2HB_DB_TYPE_REGION_LIVENODES   4
 84 #define O2HB_DB_TYPE_REGION_NUMBER      5
 85 #define O2HB_DB_TYPE_REGION_ELAPSED_TIME        6
 86 #define O2HB_DB_TYPE_REGION_PINNED      7
 87 struct o2hb_debug_buf {
 88         int db_type;
 89         int db_size;
 90         int db_len;
 91         void *db_data;
 92 };
 93 
 94 static struct o2hb_debug_buf *o2hb_db_livenodes;
 95 static struct o2hb_debug_buf *o2hb_db_liveregions;
 96 static struct o2hb_debug_buf *o2hb_db_quorumregions;
 97 static struct o2hb_debug_buf *o2hb_db_failedregions;
 98 
 99 #define O2HB_DEBUG_DIR                  "o2hb"
100 #define O2HB_DEBUG_LIVENODES            "livenodes"
101 #define O2HB_DEBUG_LIVEREGIONS          "live_regions"
102 #define O2HB_DEBUG_QUORUMREGIONS        "quorum_regions"
103 #define O2HB_DEBUG_FAILEDREGIONS        "failed_regions"
104 #define O2HB_DEBUG_REGION_NUMBER        "num"
105 #define O2HB_DEBUG_REGION_ELAPSED_TIME  "elapsed_time_in_ms"
106 #define O2HB_DEBUG_REGION_PINNED        "pinned"
107 
108 static struct dentry *o2hb_debug_dir;
109 static struct dentry *o2hb_debug_livenodes;
110 static struct dentry *o2hb_debug_liveregions;
111 static struct dentry *o2hb_debug_quorumregions;
112 static struct dentry *o2hb_debug_failedregions;
113 
114 static LIST_HEAD(o2hb_all_regions);
115 
116 static struct o2hb_callback {
117         struct list_head list;
118 } o2hb_callbacks[O2HB_NUM_CB];
119 
120 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type);
121 
122 #define O2HB_DEFAULT_BLOCK_BITS       9
123 
124 enum o2hb_heartbeat_modes {
125         O2HB_HEARTBEAT_LOCAL            = 0,
126         O2HB_HEARTBEAT_GLOBAL,
127         O2HB_HEARTBEAT_NUM_MODES,
128 };
129 
130 char *o2hb_heartbeat_mode_desc[O2HB_HEARTBEAT_NUM_MODES] = {
131                 "local",        /* O2HB_HEARTBEAT_LOCAL */
132                 "global",       /* O2HB_HEARTBEAT_GLOBAL */
133 };
134 
135 unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
136 unsigned int o2hb_heartbeat_mode = O2HB_HEARTBEAT_LOCAL;
137 
138 /*
139  * o2hb_dependent_users tracks the number of registered callbacks that depend
140  * on heartbeat. o2net and o2dlm are two entities that register this callback.
141  * However only o2dlm depends on the heartbeat. It does not want the heartbeat
142  * to stop while a dlm domain is still active.
143  */
144 unsigned int o2hb_dependent_users;
145 
146 /*
147  * In global heartbeat mode, all regions are pinned if there are one or more
148  * dependent users and the quorum region count is <= O2HB_PIN_CUT_OFF. All
149  * regions are unpinned if the region count exceeds the cut off or the number
150  * of dependent users falls to zero.
151  */
152 #define O2HB_PIN_CUT_OFF                3
153 
154 /*
155  * In local heartbeat mode, we assume the dlm domain name to be the same as
156  * region uuid. This is true for domains created for the file system but not
157  * necessarily true for userdlm domains. This is a known limitation.
158  *
159  * In global heartbeat mode, we pin/unpin all o2hb regions. This solution
160  * works for both file system and userdlm domains.
161  */
162 static int o2hb_region_pin(const char *region_uuid);
163 static void o2hb_region_unpin(const char *region_uuid);
164 
165 /* Only sets a new threshold if there are no active regions.
166  *
167  * No locking or otherwise interesting code is required for reading
168  * o2hb_dead_threshold as it can't change once regions are active and
169  * it's not interesting to anyone until then anyway. */
170 static void o2hb_dead_threshold_set(unsigned int threshold)
171 {
172         if (threshold > O2HB_MIN_DEAD_THRESHOLD) {
173                 spin_lock(&o2hb_live_lock);
174                 if (list_empty(&o2hb_all_regions))
175                         o2hb_dead_threshold = threshold;
176                 spin_unlock(&o2hb_live_lock);
177         }
178 }
179 
180 static int o2hb_global_heartbeat_mode_set(unsigned int hb_mode)
181 {
182         int ret = -1;
183 
184         if (hb_mode < O2HB_HEARTBEAT_NUM_MODES) {
185                 spin_lock(&o2hb_live_lock);
186                 if (list_empty(&o2hb_all_regions)) {
187                         o2hb_heartbeat_mode = hb_mode;
188                         ret = 0;
189                 }
190                 spin_unlock(&o2hb_live_lock);
191         }
192 
193         return ret;
194 }
195 
196 struct o2hb_node_event {
197         struct list_head        hn_item;
198         enum o2hb_callback_type hn_event_type;
199         struct o2nm_node        *hn_node;
200         int                     hn_node_num;
201 };
202 
203 struct o2hb_disk_slot {
204         struct o2hb_disk_heartbeat_block *ds_raw_block;
205         u8                      ds_node_num;
206         u64                     ds_last_time;
207         u64                     ds_last_generation;
208         u16                     ds_equal_samples;
209         u16                     ds_changed_samples;
210         struct list_head        ds_live_item;
211 };
212 
213 /* each thread owns a region.. when we're asked to tear down the region
214  * we ask the thread to stop, who cleans up the region */
215 struct o2hb_region {
216         struct config_item      hr_item;
217 
218         struct list_head        hr_all_item;
219         unsigned                hr_unclean_stop:1,
220                                 hr_aborted_start:1,
221                                 hr_item_pinned:1,
222                                 hr_item_dropped:1;
223 
224         /* protected by the hr_callback_sem */
225         struct task_struct      *hr_task;
226 
227         unsigned int            hr_blocks;
228         unsigned long long      hr_start_block;
229 
230         unsigned int            hr_block_bits;
231         unsigned int            hr_block_bytes;
232 
233         unsigned int            hr_slots_per_page;
234         unsigned int            hr_num_pages;
235 
236         struct page             **hr_slot_data;
237         struct block_device     *hr_bdev;
238         struct o2hb_disk_slot   *hr_slots;
239 
240         /* live node map of this region */
241         unsigned long           hr_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
242         unsigned int            hr_region_num;
243 
244         struct dentry           *hr_debug_dir;
245         struct dentry           *hr_debug_livenodes;
246         struct dentry           *hr_debug_regnum;
247         struct dentry           *hr_debug_elapsed_time;
248         struct dentry           *hr_debug_pinned;
249         struct o2hb_debug_buf   *hr_db_livenodes;
250         struct o2hb_debug_buf   *hr_db_regnum;
251         struct o2hb_debug_buf   *hr_db_elapsed_time;
252         struct o2hb_debug_buf   *hr_db_pinned;
253 
254         /* let the person setting up hb wait for it to return until it
255          * has reached a 'steady' state.  This will be fixed when we have
256          * a more complete api that doesn't lead to this sort of fragility. */
257         atomic_t                hr_steady_iterations;
258 
259         /* terminate o2hb thread if it does not reach steady state
260          * (hr_steady_iterations == 0) within hr_unsteady_iterations */
261         atomic_t                hr_unsteady_iterations;
262 
263         char                    hr_dev_name[BDEVNAME_SIZE];
264 
265         unsigned int            hr_timeout_ms;
266 
267         /* randomized as the region goes up and down so that a node
268          * recognizes a node going up and down in one iteration */
269         u64                     hr_generation;
270 
271         struct delayed_work     hr_write_timeout_work;
272         unsigned long           hr_last_timeout_start;
273 
274         /* Used during o2hb_check_slot to hold a copy of the block
275          * being checked because we temporarily have to zero out the
276          * crc field. */
277         struct o2hb_disk_heartbeat_block *hr_tmp_block;
278 };
279 
280 struct o2hb_bio_wait_ctxt {
281         atomic_t          wc_num_reqs;
282         struct completion wc_io_complete;
283         int               wc_error;
284 };
285 
286 static void o2hb_write_timeout(struct work_struct *work)
287 {
288         int failed, quorum;
289         unsigned long flags;
290         struct o2hb_region *reg =
291                 container_of(work, struct o2hb_region,
292                              hr_write_timeout_work.work);
293 
294         mlog(ML_ERROR, "Heartbeat write timeout to device %s after %u "
295              "milliseconds\n", reg->hr_dev_name,
296              jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
297 
298         if (o2hb_global_heartbeat_active()) {
299                 spin_lock_irqsave(&o2hb_live_lock, flags);
300                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
301                         set_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
302                 failed = bitmap_weight(o2hb_failed_region_bitmap,
303                                         O2NM_MAX_REGIONS);
304                 quorum = bitmap_weight(o2hb_quorum_region_bitmap,
305                                         O2NM_MAX_REGIONS);
306                 spin_unlock_irqrestore(&o2hb_live_lock, flags);
307 
308                 mlog(ML_HEARTBEAT, "Number of regions %d, failed regions %d\n",
309                      quorum, failed);
310 
311                 /*
312                  * Fence if the number of failed regions >= half the number
313                  * of  quorum regions
314                  */
315                 if ((failed << 1) < quorum)
316                         return;
317         }
318 
319         o2quo_disk_timeout();
320 }
321 
322 static void o2hb_arm_write_timeout(struct o2hb_region *reg)
323 {
324         /* Arm writeout only after thread reaches steady state */
325         if (atomic_read(&reg->hr_steady_iterations) != 0)
326                 return;
327 
328         mlog(ML_HEARTBEAT, "Queue write timeout for %u ms\n",
329              O2HB_MAX_WRITE_TIMEOUT_MS);
330 
331         if (o2hb_global_heartbeat_active()) {
332                 spin_lock(&o2hb_live_lock);
333                 clear_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
334                 spin_unlock(&o2hb_live_lock);
335         }
336         cancel_delayed_work(&reg->hr_write_timeout_work);
337         reg->hr_last_timeout_start = jiffies;
338         schedule_delayed_work(&reg->hr_write_timeout_work,
339                               msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
340 }
341 
342 static void o2hb_disarm_write_timeout(struct o2hb_region *reg)
343 {
344         cancel_delayed_work_sync(&reg->hr_write_timeout_work);
345 }
346 
347 static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
348 {
349         atomic_set(&wc->wc_num_reqs, 1);
350         init_completion(&wc->wc_io_complete);
351         wc->wc_error = 0;
352 }
353 
354 /* Used in error paths too */
355 static inline void o2hb_bio_wait_dec(struct o2hb_bio_wait_ctxt *wc,
356                                      unsigned int num)
357 {
358         /* sadly atomic_sub_and_test() isn't available on all platforms.  The
359          * good news is that the fast path only completes one at a time */
360         while(num--) {
361                 if (atomic_dec_and_test(&wc->wc_num_reqs)) {
362                         BUG_ON(num > 0);
363                         complete(&wc->wc_io_complete);
364                 }
365         }
366 }
367 
368 static void o2hb_wait_on_io(struct o2hb_region *reg,
369                             struct o2hb_bio_wait_ctxt *wc)
370 {
371         o2hb_bio_wait_dec(wc, 1);
372         wait_for_completion(&wc->wc_io_complete);
373 }
374 
375 static void o2hb_bio_end_io(struct bio *bio,
376                            int error)
377 {
378         struct o2hb_bio_wait_ctxt *wc = bio->bi_private;
379 
380         if (error) {
381                 mlog(ML_ERROR, "IO Error %d\n", error);
382                 wc->wc_error = error;
383         }
384 
385         o2hb_bio_wait_dec(wc, 1);
386         bio_put(bio);
387 }
388 
389 /* Setup a Bio to cover I/O against num_slots slots starting at
390  * start_slot. */
391 static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
392                                       struct o2hb_bio_wait_ctxt *wc,
393                                       unsigned int *current_slot,
394                                       unsigned int max_slots)
395 {
396         int len, current_page;
397         unsigned int vec_len, vec_start;
398         unsigned int bits = reg->hr_block_bits;
399         unsigned int spp = reg->hr_slots_per_page;
400         unsigned int cs = *current_slot;
401         struct bio *bio;
402         struct page *page;
403 
404         /* Testing has shown this allocation to take long enough under
405          * GFP_KERNEL that the local node can get fenced. It would be
406          * nicest if we could pre-allocate these bios and avoid this
407          * all together. */
408         bio = bio_alloc(GFP_ATOMIC, 16);
409         if (!bio) {
410                 mlog(ML_ERROR, "Could not alloc slots BIO!\n");
411                 bio = ERR_PTR(-ENOMEM);
412                 goto bail;
413         }
414 
415         /* Must put everything in 512 byte sectors for the bio... */
416         bio->bi_iter.bi_sector = (reg->hr_start_block + cs) << (bits - 9);
417         bio->bi_bdev = reg->hr_bdev;
418         bio->bi_private = wc;
419         bio->bi_end_io = o2hb_bio_end_io;
420 
421         vec_start = (cs << bits) % PAGE_CACHE_SIZE;
422         while(cs < max_slots) {
423                 current_page = cs / spp;
424                 page = reg->hr_slot_data[current_page];
425 
426                 vec_len = min(PAGE_CACHE_SIZE - vec_start,
427                               (max_slots-cs) * (PAGE_CACHE_SIZE/spp) );
428 
429                 mlog(ML_HB_BIO, "page %d, vec_len = %u, vec_start = %u\n",
430                      current_page, vec_len, vec_start);
431 
432                 len = bio_add_page(bio, page, vec_len, vec_start);
433                 if (len != vec_len) break;
434 
435                 cs += vec_len / (PAGE_CACHE_SIZE/spp);
436                 vec_start = 0;
437         }
438 
439 bail:
440         *current_slot = cs;
441         return bio;
442 }
443 
444 static int o2hb_read_slots(struct o2hb_region *reg,
445                            unsigned int max_slots)
446 {
447         unsigned int current_slot=0;
448         int status;
449         struct o2hb_bio_wait_ctxt wc;
450         struct bio *bio;
451 
452         o2hb_bio_wait_init(&wc);
453 
454         while(current_slot < max_slots) {
455                 bio = o2hb_setup_one_bio(reg, &wc, &current_slot, max_slots);
456                 if (IS_ERR(bio)) {
457                         status = PTR_ERR(bio);
458                         mlog_errno(status);
459                         goto bail_and_wait;
460                 }
461 
462                 atomic_inc(&wc.wc_num_reqs);
463                 submit_bio(READ, bio);
464         }
465 
466         status = 0;
467 
468 bail_and_wait:
469         o2hb_wait_on_io(reg, &wc);
470         if (wc.wc_error && !status)
471                 status = wc.wc_error;
472 
473         return status;
474 }
475 
476 static int o2hb_issue_node_write(struct o2hb_region *reg,
477                                  struct o2hb_bio_wait_ctxt *write_wc)
478 {
479         int status;
480         unsigned int slot;
481         struct bio *bio;
482 
483         o2hb_bio_wait_init(write_wc);
484 
485         slot = o2nm_this_node();
486 
487         bio = o2hb_setup_one_bio(reg, write_wc, &slot, slot+1);
488         if (IS_ERR(bio)) {
489                 status = PTR_ERR(bio);
490                 mlog_errno(status);
491                 goto bail;
492         }
493 
494         atomic_inc(&write_wc->wc_num_reqs);
495         submit_bio(WRITE_SYNC, bio);
496 
497         status = 0;
498 bail:
499         return status;
500 }
501 
502 static u32 o2hb_compute_block_crc_le(struct o2hb_region *reg,
503                                      struct o2hb_disk_heartbeat_block *hb_block)
504 {
505         __le32 old_cksum;
506         u32 ret;
507 
508         /* We want to compute the block crc with a 0 value in the
509          * hb_cksum field. Save it off here and replace after the
510          * crc. */
511         old_cksum = hb_block->hb_cksum;
512         hb_block->hb_cksum = 0;
513 
514         ret = crc32_le(0, (unsigned char *) hb_block, reg->hr_block_bytes);
515 
516         hb_block->hb_cksum = old_cksum;
517 
518         return ret;
519 }
520 
521 static void o2hb_dump_slot(struct o2hb_disk_heartbeat_block *hb_block)
522 {
523         mlog(ML_ERROR, "Dump slot information: seq = 0x%llx, node = %u, "
524              "cksum = 0x%x, generation 0x%llx\n",
525              (long long)le64_to_cpu(hb_block->hb_seq),
526              hb_block->hb_node, le32_to_cpu(hb_block->hb_cksum),
527              (long long)le64_to_cpu(hb_block->hb_generation));
528 }
529 
530 static int o2hb_verify_crc(struct o2hb_region *reg,
531                            struct o2hb_disk_heartbeat_block *hb_block)
532 {
533         u32 read, computed;
534 
535         read = le32_to_cpu(hb_block->hb_cksum);
536         computed = o2hb_compute_block_crc_le(reg, hb_block);
537 
538         return read == computed;
539 }
540 
541 /*
542  * Compare the slot data with what we wrote in the last iteration.
543  * If the match fails, print an appropriate error message. This is to
544  * detect errors like... another node hearting on the same slot,
545  * flaky device that is losing writes, etc.
546  * Returns 1 if check succeeds, 0 otherwise.
547  */
548 static int o2hb_check_own_slot(struct o2hb_region *reg)
549 {
550         struct o2hb_disk_slot *slot;
551         struct o2hb_disk_heartbeat_block *hb_block;
552         char *errstr;
553 
554         slot = &reg->hr_slots[o2nm_this_node()];
555         /* Don't check on our 1st timestamp */
556         if (!slot->ds_last_time)
557                 return 0;
558 
559         hb_block = slot->ds_raw_block;
560         if (le64_to_cpu(hb_block->hb_seq) == slot->ds_last_time &&
561             le64_to_cpu(hb_block->hb_generation) == slot->ds_last_generation &&
562             hb_block->hb_node == slot->ds_node_num)
563                 return 1;
564 
565 #define ERRSTR1         "Another node is heartbeating on device"
566 #define ERRSTR2         "Heartbeat generation mismatch on device"
567 #define ERRSTR3         "Heartbeat sequence mismatch on device"
568 
569         if (hb_block->hb_node != slot->ds_node_num)
570                 errstr = ERRSTR1;
571         else if (le64_to_cpu(hb_block->hb_generation) !=
572                  slot->ds_last_generation)
573                 errstr = ERRSTR2;
574         else
575                 errstr = ERRSTR3;
576 
577         mlog(ML_ERROR, "%s (%s): expected(%u:0x%llx, 0x%llx), "
578              "ondisk(%u:0x%llx, 0x%llx)\n", errstr, reg->hr_dev_name,
579              slot->ds_node_num, (unsigned long long)slot->ds_last_generation,
580              (unsigned long long)slot->ds_last_time, hb_block->hb_node,
581              (unsigned long long)le64_to_cpu(hb_block->hb_generation),
582              (unsigned long long)le64_to_cpu(hb_block->hb_seq));
583 
584         return 0;
585 }
586 
587 static inline void o2hb_prepare_block(struct o2hb_region *reg,
588                                       u64 generation)
589 {
590         int node_num;
591         u64 cputime;
592         struct o2hb_disk_slot *slot;
593         struct o2hb_disk_heartbeat_block *hb_block;
594 
595         node_num = o2nm_this_node();
596         slot = &reg->hr_slots[node_num];
597 
598         hb_block = (struct o2hb_disk_heartbeat_block *)slot->ds_raw_block;
599         memset(hb_block, 0, reg->hr_block_bytes);
600         /* TODO: time stuff */
601         cputime = CURRENT_TIME.tv_sec;
602         if (!cputime)
603                 cputime = 1;
604 
605         hb_block->hb_seq = cpu_to_le64(cputime);
606         hb_block->hb_node = node_num;
607         hb_block->hb_generation = cpu_to_le64(generation);
608         hb_block->hb_dead_ms = cpu_to_le32(o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS);
609 
610         /* This step must always happen last! */
611         hb_block->hb_cksum = cpu_to_le32(o2hb_compute_block_crc_le(reg,
612                                                                    hb_block));
613 
614         mlog(ML_HB_BIO, "our node generation = 0x%llx, cksum = 0x%x\n",
615              (long long)generation,
616              le32_to_cpu(hb_block->hb_cksum));
617 }
618 
619 static void o2hb_fire_callbacks(struct o2hb_callback *hbcall,
620                                 struct o2nm_node *node,
621                                 int idx)
622 {
623         struct o2hb_callback_func *f;
624 
625         list_for_each_entry(f, &hbcall->list, hc_item) {
626                 mlog(ML_HEARTBEAT, "calling funcs %p\n", f);
627                 (f->hc_func)(node, idx, f->hc_data);
628         }
629 }
630 
631 /* Will run the list in order until we process the passed event */
632 static void o2hb_run_event_list(struct o2hb_node_event *queued_event)
633 {
634         struct o2hb_callback *hbcall;
635         struct o2hb_node_event *event;
636 
637         /* Holding callback sem assures we don't alter the callback
638          * lists when doing this, and serializes ourselves with other
639          * processes wanting callbacks. */
640         down_write(&o2hb_callback_sem);
641 
642         spin_lock(&o2hb_live_lock);
643         while (!list_empty(&o2hb_node_events)
644                && !list_empty(&queued_event->hn_item)) {
645                 event = list_entry(o2hb_node_events.next,
646                                    struct o2hb_node_event,
647                                    hn_item);
648                 list_del_init(&event->hn_item);
649                 spin_unlock(&o2hb_live_lock);
650 
651                 mlog(ML_HEARTBEAT, "Node %s event for %d\n",
652                      event->hn_event_type == O2HB_NODE_UP_CB ? "UP" : "DOWN",
653                      event->hn_node_num);
654 
655                 hbcall = hbcall_from_type(event->hn_event_type);
656 
657                 /* We should *never* have gotten on to the list with a
658                  * bad type... This isn't something that we should try
659                  * to recover from. */
660                 BUG_ON(IS_ERR(hbcall));
661 
662                 o2hb_fire_callbacks(hbcall, event->hn_node, event->hn_node_num);
663 
664                 spin_lock(&o2hb_live_lock);
665         }
666         spin_unlock(&o2hb_live_lock);
667 
668         up_write(&o2hb_callback_sem);
669 }
670 
671 static void o2hb_queue_node_event(struct o2hb_node_event *event,
672                                   enum o2hb_callback_type type,
673                                   struct o2nm_node *node,
674                                   int node_num)
675 {
676         assert_spin_locked(&o2hb_live_lock);
677 
678         BUG_ON((!node) && (type != O2HB_NODE_DOWN_CB));
679 
680         event->hn_event_type = type;
681         event->hn_node = node;
682         event->hn_node_num = node_num;
683 
684         mlog(ML_HEARTBEAT, "Queue node %s event for node %d\n",
685              type == O2HB_NODE_UP_CB ? "UP" : "DOWN", node_num);
686 
687         list_add_tail(&event->hn_item, &o2hb_node_events);
688 }
689 
690 static void o2hb_shutdown_slot(struct o2hb_disk_slot *slot)
691 {
692         struct o2hb_node_event event =
693                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
694         struct o2nm_node *node;
695         int queued = 0;
696 
697         node = o2nm_get_node_by_num(slot->ds_node_num);
698         if (!node)
699                 return;
700 
701         spin_lock(&o2hb_live_lock);
702         if (!list_empty(&slot->ds_live_item)) {
703                 mlog(ML_HEARTBEAT, "Shutdown, node %d leaves region\n",
704                      slot->ds_node_num);
705 
706                 list_del_init(&slot->ds_live_item);
707 
708                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
709                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
710 
711                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB, node,
712                                               slot->ds_node_num);
713                         queued = 1;
714                 }
715         }
716         spin_unlock(&o2hb_live_lock);
717 
718         if (queued)
719                 o2hb_run_event_list(&event);
720 
721         o2nm_node_put(node);
722 }
723 
724 static void o2hb_set_quorum_device(struct o2hb_region *reg)
725 {
726         if (!o2hb_global_heartbeat_active())
727                 return;
728 
729         /* Prevent race with o2hb_heartbeat_group_drop_item() */
730         if (kthread_should_stop())
731                 return;
732 
733         /* Tag region as quorum only after thread reaches steady state */
734         if (atomic_read(&reg->hr_steady_iterations) != 0)
735                 return;
736 
737         spin_lock(&o2hb_live_lock);
738 
739         if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
740                 goto unlock;
741 
742         /*
743          * A region can be added to the quorum only when it sees all
744          * live nodes heartbeat on it. In other words, the region has been
745          * added to all nodes.
746          */
747         if (memcmp(reg->hr_live_node_bitmap, o2hb_live_node_bitmap,
748                    sizeof(o2hb_live_node_bitmap)))
749                 goto unlock;
750 
751         printk(KERN_NOTICE "o2hb: Region %s (%s) is now a quorum device\n",
752                config_item_name(&reg->hr_item), reg->hr_dev_name);
753 
754         set_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
755 
756         /*
757          * If global heartbeat active, unpin all regions if the
758          * region count > CUT_OFF
759          */
760         if (bitmap_weight(o2hb_quorum_region_bitmap,
761                            O2NM_MAX_REGIONS) > O2HB_PIN_CUT_OFF)
762                 o2hb_region_unpin(NULL);
763 unlock:
764         spin_unlock(&o2hb_live_lock);
765 }
766 
767 static int o2hb_check_slot(struct o2hb_region *reg,
768                            struct o2hb_disk_slot *slot)
769 {
770         int changed = 0, gen_changed = 0;
771         struct o2hb_node_event event =
772                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
773         struct o2nm_node *node;
774         struct o2hb_disk_heartbeat_block *hb_block = reg->hr_tmp_block;
775         u64 cputime;
776         unsigned int dead_ms = o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS;
777         unsigned int slot_dead_ms;
778         int tmp;
779         int queued = 0;
780 
781         memcpy(hb_block, slot->ds_raw_block, reg->hr_block_bytes);
782 
783         /*
784          * If a node is no longer configured but is still in the livemap, we
785          * may need to clear that bit from the livemap.
786          */
787         node = o2nm_get_node_by_num(slot->ds_node_num);
788         if (!node) {
789                 spin_lock(&o2hb_live_lock);
790                 tmp = test_bit(slot->ds_node_num, o2hb_live_node_bitmap);
791                 spin_unlock(&o2hb_live_lock);
792                 if (!tmp)
793                         return 0;
794         }
795 
796         if (!o2hb_verify_crc(reg, hb_block)) {
797                 /* all paths from here will drop o2hb_live_lock for
798                  * us. */
799                 spin_lock(&o2hb_live_lock);
800 
801                 /* Don't print an error on the console in this case -
802                  * a freshly formatted heartbeat area will not have a
803                  * crc set on it. */
804                 if (list_empty(&slot->ds_live_item))
805                         goto out;
806 
807                 /* The node is live but pushed out a bad crc. We
808                  * consider it a transient miss but don't populate any
809                  * other values as they may be junk. */
810                 mlog(ML_ERROR, "Node %d has written a bad crc to %s\n",
811                      slot->ds_node_num, reg->hr_dev_name);
812                 o2hb_dump_slot(hb_block);
813 
814                 slot->ds_equal_samples++;
815                 goto fire_callbacks;
816         }
817 
818         /* we don't care if these wrap.. the state transitions below
819          * clear at the right places */
820         cputime = le64_to_cpu(hb_block->hb_seq);
821         if (slot->ds_last_time != cputime)
822                 slot->ds_changed_samples++;
823         else
824                 slot->ds_equal_samples++;
825         slot->ds_last_time = cputime;
826 
827         /* The node changed heartbeat generations. We assume this to
828          * mean it dropped off but came back before we timed out. We
829          * want to consider it down for the time being but don't want
830          * to lose any changed_samples state we might build up to
831          * considering it live again. */
832         if (slot->ds_last_generation != le64_to_cpu(hb_block->hb_generation)) {
833                 gen_changed = 1;
834                 slot->ds_equal_samples = 0;
835                 mlog(ML_HEARTBEAT, "Node %d changed generation (0x%llx "
836                      "to 0x%llx)\n", slot->ds_node_num,
837                      (long long)slot->ds_last_generation,
838                      (long long)le64_to_cpu(hb_block->hb_generation));
839         }
840 
841         slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
842 
843         mlog(ML_HEARTBEAT, "Slot %d gen 0x%llx cksum 0x%x "
844              "seq %llu last %llu changed %u equal %u\n",
845              slot->ds_node_num, (long long)slot->ds_last_generation,
846              le32_to_cpu(hb_block->hb_cksum),
847              (unsigned long long)le64_to_cpu(hb_block->hb_seq),
848              (unsigned long long)slot->ds_last_time, slot->ds_changed_samples,
849              slot->ds_equal_samples);
850 
851         spin_lock(&o2hb_live_lock);
852 
853 fire_callbacks:
854         /* dead nodes only come to life after some number of
855          * changes at any time during their dead time */
856         if (list_empty(&slot->ds_live_item) &&
857             slot->ds_changed_samples >= O2HB_LIVE_THRESHOLD) {
858                 mlog(ML_HEARTBEAT, "Node %d (id 0x%llx) joined my region\n",
859                      slot->ds_node_num, (long long)slot->ds_last_generation);
860 
861                 set_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
862 
863                 /* first on the list generates a callback */
864                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
865                         mlog(ML_HEARTBEAT, "o2hb: Add node %d to live nodes "
866                              "bitmap\n", slot->ds_node_num);
867                         set_bit(slot->ds_node_num, o2hb_live_node_bitmap);
868 
869                         o2hb_queue_node_event(&event, O2HB_NODE_UP_CB, node,
870                                               slot->ds_node_num);
871 
872                         changed = 1;
873                         queued = 1;
874                 }
875 
876                 list_add_tail(&slot->ds_live_item,
877                               &o2hb_live_slots[slot->ds_node_num]);
878 
879                 slot->ds_equal_samples = 0;
880 
881                 /* We want to be sure that all nodes agree on the
882                  * number of milliseconds before a node will be
883                  * considered dead. The self-fencing timeout is
884                  * computed from this value, and a discrepancy might
885                  * result in heartbeat calling a node dead when it
886                  * hasn't self-fenced yet. */
887                 slot_dead_ms = le32_to_cpu(hb_block->hb_dead_ms);
888                 if (slot_dead_ms && slot_dead_ms != dead_ms) {
889                         /* TODO: Perhaps we can fail the region here. */
890                         mlog(ML_ERROR, "Node %d on device %s has a dead count "
891                              "of %u ms, but our count is %u ms.\n"
892                              "Please double check your configuration values "
893                              "for 'O2CB_HEARTBEAT_THRESHOLD'\n",
894                              slot->ds_node_num, reg->hr_dev_name, slot_dead_ms,
895                              dead_ms);
896                 }
897                 goto out;
898         }
899 
900         /* if the list is dead, we're done.. */
901         if (list_empty(&slot->ds_live_item))
902                 goto out;
903 
904         /* live nodes only go dead after enough consequtive missed
905          * samples..  reset the missed counter whenever we see
906          * activity */
907         if (slot->ds_equal_samples >= o2hb_dead_threshold || gen_changed) {
908                 mlog(ML_HEARTBEAT, "Node %d left my region\n",
909                      slot->ds_node_num);
910 
911                 clear_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
912 
913                 /* last off the live_slot generates a callback */
914                 list_del_init(&slot->ds_live_item);
915                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
916                         mlog(ML_HEARTBEAT, "o2hb: Remove node %d from live "
917                              "nodes bitmap\n", slot->ds_node_num);
918                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
919 
920                         /* node can be null */
921                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB,
922                                               node, slot->ds_node_num);
923 
924                         changed = 1;
925                         queued = 1;
926                 }
927 
928                 /* We don't clear this because the node is still
929                  * actually writing new blocks. */
930                 if (!gen_changed)
931                         slot->ds_changed_samples = 0;
932                 goto out;
933         }
934         if (slot->ds_changed_samples) {
935                 slot->ds_changed_samples = 0;
936                 slot->ds_equal_samples = 0;
937         }
938 out:
939         spin_unlock(&o2hb_live_lock);
940 
941         if (queued)
942                 o2hb_run_event_list(&event);
943 
944         if (node)
945                 o2nm_node_put(node);
946         return changed;
947 }
948 
949 static int o2hb_highest_node(unsigned long *nodes, int numbits)
950 {
951         return find_last_bit(nodes, numbits);
952 }
953 
954 static int o2hb_do_disk_heartbeat(struct o2hb_region *reg)
955 {
956         int i, ret, highest_node;
957         int membership_change = 0, own_slot_ok = 0;
958         unsigned long configured_nodes[BITS_TO_LONGS(O2NM_MAX_NODES)];
959         unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
960         struct o2hb_bio_wait_ctxt write_wc;
961 
962         ret = o2nm_configured_node_map(configured_nodes,
963                                        sizeof(configured_nodes));
964         if (ret) {
965                 mlog_errno(ret);
966                 goto bail;
967         }
968 
969         /*
970          * If a node is not configured but is in the livemap, we still need
971          * to read the slot so as to be able to remove it from the livemap.
972          */
973         o2hb_fill_node_map(live_node_bitmap, sizeof(live_node_bitmap));
974         i = -1;
975         while ((i = find_next_bit(live_node_bitmap,
976                                   O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
977                 set_bit(i, configured_nodes);
978         }
979 
980         highest_node = o2hb_highest_node(configured_nodes, O2NM_MAX_NODES);
981         if (highest_node >= O2NM_MAX_NODES) {
982                 mlog(ML_NOTICE, "o2hb: No configured nodes found!\n");
983                 ret = -EINVAL;
984                 goto bail;
985         }
986 
987         /* No sense in reading the slots of nodes that don't exist
988          * yet. Of course, if the node definitions have holes in them
989          * then we're reading an empty slot anyway... Consider this
990          * best-effort. */
991         ret = o2hb_read_slots(reg, highest_node + 1);
992         if (ret < 0) {
993                 mlog_errno(ret);
994                 goto bail;
995         }
996 
997         /* With an up to date view of the slots, we can check that no
998          * other node has been improperly configured to heartbeat in
999          * our slot. */
1000         own_slot_ok = o2hb_check_own_slot(reg);
1001 
1002         /* fill in the proper info for our next heartbeat */
1003         o2hb_prepare_block(reg, reg->hr_generation);
1004 
1005         ret = o2hb_issue_node_write(reg, &write_wc);
1006         if (ret < 0) {
1007                 mlog_errno(ret);
1008                 goto bail;
1009         }
1010 
1011         i = -1;
1012         while((i = find_next_bit(configured_nodes,
1013                                  O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
1014                 membership_change |= o2hb_check_slot(reg, &reg->hr_slots[i]);
1015         }
1016 
1017         /*
1018          * We have to be sure we've advertised ourselves on disk
1019          * before we can go to steady state.  This ensures that
1020          * people we find in our steady state have seen us.
1021          */
1022         o2hb_wait_on_io(reg, &write_wc);
1023         if (write_wc.wc_error) {
1024                 /* Do not re-arm the write timeout on I/O error - we
1025                  * can't be sure that the new block ever made it to
1026                  * disk */
1027                 mlog(ML_ERROR, "Write error %d on device \"%s\"\n",
1028                      write_wc.wc_error, reg->hr_dev_name);
1029                 ret = write_wc.wc_error;
1030                 goto bail;
1031         }
1032 
1033         /* Skip disarming the timeout if own slot has stale/bad data */
1034         if (own_slot_ok) {
1035                 o2hb_set_quorum_device(reg);
1036                 o2hb_arm_write_timeout(reg);
1037         }
1038 
1039 bail:
1040         /* let the person who launched us know when things are steady */
1041         if (atomic_read(&reg->hr_steady_iterations) != 0) {
1042                 if (!ret && own_slot_ok && !membership_change) {
1043                         if (atomic_dec_and_test(&reg->hr_steady_iterations))
1044                                 wake_up(&o2hb_steady_queue);
1045                 }
1046         }
1047 
1048         if (atomic_read(&reg->hr_steady_iterations) != 0) {
1049                 if (atomic_dec_and_test(&reg->hr_unsteady_iterations)) {
1050                         printk(KERN_NOTICE "o2hb: Unable to stabilize "
1051                                "heartbeart on region %s (%s)\n",
1052                                config_item_name(&reg->hr_item),
1053                                reg->hr_dev_name);
1054                         atomic_set(&reg->hr_steady_iterations, 0);
1055                         reg->hr_aborted_start = 1;
1056                         wake_up(&o2hb_steady_queue);
1057                         ret = -EIO;
1058                 }
1059         }
1060 
1061         return ret;
1062 }
1063 
1064 /* Subtract b from a, storing the result in a. a *must* have a larger
1065  * value than b. */
1066 static void o2hb_tv_subtract(struct timeval *a,
1067                              struct timeval *b)
1068 {
1069         /* just return 0 when a is after b */
1070         if (a->tv_sec < b->tv_sec ||
1071             (a->tv_sec == b->tv_sec && a->tv_usec < b->tv_usec)) {
1072                 a->tv_sec = 0;
1073                 a->tv_usec = 0;
1074                 return;
1075         }
1076 
1077         a->tv_sec -= b->tv_sec;
1078         a->tv_usec -= b->tv_usec;
1079         while ( a->tv_usec < 0 ) {
1080                 a->tv_sec--;
1081                 a->tv_usec += 1000000;
1082         }
1083 }
1084 
1085 static unsigned int o2hb_elapsed_msecs(struct timeval *start,
1086                                        struct timeval *end)
1087 {
1088         struct timeval res = *end;
1089 
1090         o2hb_tv_subtract(&res, start);
1091 
1092         return res.tv_sec * 1000 + res.tv_usec / 1000;
1093 }
1094 
1095 /*
1096  * we ride the region ref that the region dir holds.  before the region
1097  * dir is removed and drops it ref it will wait to tear down this
1098  * thread.
1099  */
1100 static int o2hb_thread(void *data)
1101 {
1102         int i, ret;
1103         struct o2hb_region *reg = data;
1104         struct o2hb_bio_wait_ctxt write_wc;
1105         struct timeval before_hb, after_hb;
1106         unsigned int elapsed_msec;
1107 
1108         mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n");
1109 
1110         set_user_nice(current, MIN_NICE);
1111 
1112         /* Pin node */
1113         o2nm_depend_this_node();
1114 
1115         while (!kthread_should_stop() &&
1116                !reg->hr_unclean_stop && !reg->hr_aborted_start) {
1117                 /* We track the time spent inside
1118                  * o2hb_do_disk_heartbeat so that we avoid more than
1119                  * hr_timeout_ms between disk writes. On busy systems
1120                  * this should result in a heartbeat which is less
1121                  * likely to time itself out. */
1122                 do_gettimeofday(&before_hb);
1123 
1124                 ret = o2hb_do_disk_heartbeat(reg);
1125 
1126                 do_gettimeofday(&after_hb);
1127                 elapsed_msec = o2hb_elapsed_msecs(&before_hb, &after_hb);
1128 
1129                 mlog(ML_HEARTBEAT,
1130                      "start = %lu.%lu, end = %lu.%lu, msec = %u, ret = %d\n",
1131                      before_hb.tv_sec, (unsigned long) before_hb.tv_usec,
1132                      after_hb.tv_sec, (unsigned long) after_hb.tv_usec,
1133                      elapsed_msec, ret);
1134 
1135                 if (!kthread_should_stop() &&
1136                     elapsed_msec < reg->hr_timeout_ms) {
1137                         /* the kthread api has blocked signals for us so no
1138                          * need to record the return value. */
1139                         msleep_interruptible(reg->hr_timeout_ms - elapsed_msec);
1140                 }
1141         }
1142 
1143         o2hb_disarm_write_timeout(reg);
1144 
1145         /* unclean stop is only used in very bad situation */
1146         for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
1147                 o2hb_shutdown_slot(&reg->hr_slots[i]);
1148 
1149         /* Explicit down notification - avoid forcing the other nodes
1150          * to timeout on this region when we could just as easily
1151          * write a clear generation - thus indicating to them that
1152          * this node has left this region.
1153          */
1154         if (!reg->hr_unclean_stop && !reg->hr_aborted_start) {
1155                 o2hb_prepare_block(reg, 0);
1156                 ret = o2hb_issue_node_write(reg, &write_wc);
1157                 if (ret == 0)
1158                         o2hb_wait_on_io(reg, &write_wc);
1159                 else
1160                         mlog_errno(ret);
1161         }
1162 
1163         /* Unpin node */
1164         o2nm_undepend_this_node();
1165 
1166         mlog(ML_HEARTBEAT|ML_KTHREAD, "o2hb thread exiting\n");
1167 
1168         return 0;
1169 }
1170 
1171 #ifdef CONFIG_DEBUG_FS
1172 static int o2hb_debug_open(struct inode *inode, struct file *file)
1173 {
1174         struct o2hb_debug_buf *db = inode->i_private;
1175         struct o2hb_region *reg;
1176         unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1177         unsigned long lts;
1178         char *buf = NULL;
1179         int i = -1;
1180         int out = 0;
1181 
1182         /* max_nodes should be the largest bitmap we pass here */
1183         BUG_ON(sizeof(map) < db->db_size);
1184 
1185         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1186         if (!buf)
1187                 goto bail;
1188 
1189         switch (db->db_type) {
1190         case O2HB_DB_TYPE_LIVENODES:
1191         case O2HB_DB_TYPE_LIVEREGIONS:
1192         case O2HB_DB_TYPE_QUORUMREGIONS:
1193         case O2HB_DB_TYPE_FAILEDREGIONS:
1194                 spin_lock(&o2hb_live_lock);
1195                 memcpy(map, db->db_data, db->db_size);
1196                 spin_unlock(&o2hb_live_lock);
1197                 break;
1198 
1199         case O2HB_DB_TYPE_REGION_LIVENODES:
1200                 spin_lock(&o2hb_live_lock);
1201                 reg = (struct o2hb_region *)db->db_data;
1202                 memcpy(map, reg->hr_live_node_bitmap, db->db_size);
1203                 spin_unlock(&o2hb_live_lock);
1204                 break;
1205 
1206         case O2HB_DB_TYPE_REGION_NUMBER:
1207                 reg = (struct o2hb_region *)db->db_data;
1208                 out += snprintf(buf + out, PAGE_SIZE - out, "%d\n",
1209                                 reg->hr_region_num);
1210                 goto done;
1211 
1212         case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
1213                 reg = (struct o2hb_region *)db->db_data;
1214                 lts = reg->hr_last_timeout_start;
1215                 /* If 0, it has never been set before */
1216                 if (lts)
1217                         lts = jiffies_to_msecs(jiffies - lts);
1218                 out += snprintf(buf + out, PAGE_SIZE - out, "%lu\n", lts);
1219                 goto done;
1220 
1221         case O2HB_DB_TYPE_REGION_PINNED:
1222                 reg = (struct o2hb_region *)db->db_data;
1223                 out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
1224                                 !!reg->hr_item_pinned);
1225                 goto done;
1226 
1227         default:
1228                 goto done;
1229         }
1230 
1231         while ((i = find_next_bit(map, db->db_len, i + 1)) < db->db_len)
1232                 out += snprintf(buf + out, PAGE_SIZE - out, "%d ", i);
1233         out += snprintf(buf + out, PAGE_SIZE - out, "\n");
1234 
1235 done:
1236         i_size_write(inode, out);
1237 
1238         file->private_data = buf;
1239 
1240         return 0;
1241 bail:
1242         return -ENOMEM;
1243 }
1244 
1245 static int o2hb_debug_release(struct inode *inode, struct file *file)
1246 {
1247         kfree(file->private_data);
1248         return 0;
1249 }
1250 
1251 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1252                                  size_t nbytes, loff_t *ppos)
1253 {
1254         return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
1255                                        i_size_read(file->f_mapping->host));
1256 }
1257 #else
1258 static int o2hb_debug_open(struct inode *inode, struct file *file)
1259 {
1260         return 0;
1261 }
1262 static int o2hb_debug_release(struct inode *inode, struct file *file)
1263 {
1264         return 0;
1265 }
1266 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1267                                size_t nbytes, loff_t *ppos)
1268 {
1269         return 0;
1270 }
1271 #endif  /* CONFIG_DEBUG_FS */
1272 
1273 static const struct file_operations o2hb_debug_fops = {
1274         .open =         o2hb_debug_open,
1275         .release =      o2hb_debug_release,
1276         .read =         o2hb_debug_read,
1277         .llseek =       generic_file_llseek,
1278 };
1279 
1280 void o2hb_exit(void)
1281 {
1282         kfree(o2hb_db_livenodes);
1283         kfree(o2hb_db_liveregions);
1284         kfree(o2hb_db_quorumregions);
1285         kfree(o2hb_db_failedregions);
1286         debugfs_remove(o2hb_debug_failedregions);
1287         debugfs_remove(o2hb_debug_quorumregions);
1288         debugfs_remove(o2hb_debug_liveregions);
1289         debugfs_remove(o2hb_debug_livenodes);
1290         debugfs_remove(o2hb_debug_dir);
1291 }
1292 
1293 static struct dentry *o2hb_debug_create(const char *name, struct dentry *dir,
1294                                         struct o2hb_debug_buf **db, int db_len,
1295                                         int type, int size, int len, void *data)
1296 {
1297         *db = kmalloc(db_len, GFP_KERNEL);
1298         if (!*db)
1299                 return NULL;
1300 
1301         (*db)->db_type = type;
1302         (*db)->db_size = size;
1303         (*db)->db_len = len;
1304         (*db)->db_data = data;
1305 
1306         return debugfs_create_file(name, S_IFREG|S_IRUSR, dir, *db,
1307                                    &o2hb_debug_fops);
1308 }
1309 
1310 static int o2hb_debug_init(void)
1311 {
1312         int ret = -ENOMEM;
1313 
1314         o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
1315         if (!o2hb_debug_dir) {
1316                 mlog_errno(ret);
1317                 goto bail;
1318         }
1319 
1320         o2hb_debug_livenodes = o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1321                                                  o2hb_debug_dir,
1322                                                  &o2hb_db_livenodes,
1323                                                  sizeof(*o2hb_db_livenodes),
1324                                                  O2HB_DB_TYPE_LIVENODES,
1325                                                  sizeof(o2hb_live_node_bitmap),
1326                                                  O2NM_MAX_NODES,
1327                                                  o2hb_live_node_bitmap);
1328         if (!o2hb_debug_livenodes) {
1329                 mlog_errno(ret);
1330                 goto bail;
1331         }
1332 
1333         o2hb_debug_liveregions = o2hb_debug_create(O2HB_DEBUG_LIVEREGIONS,
1334                                                    o2hb_debug_dir,
1335                                                    &o2hb_db_liveregions,
1336                                                    sizeof(*o2hb_db_liveregions),
1337                                                    O2HB_DB_TYPE_LIVEREGIONS,
1338                                                    sizeof(o2hb_live_region_bitmap),
1339                                                    O2NM_MAX_REGIONS,
1340                                                    o2hb_live_region_bitmap);
1341         if (!o2hb_debug_liveregions) {
1342                 mlog_errno(ret);
1343                 goto bail;
1344         }
1345 
1346         o2hb_debug_quorumregions =
1347                         o2hb_debug_create(O2HB_DEBUG_QUORUMREGIONS,
1348                                           o2hb_debug_dir,
1349                                           &o2hb_db_quorumregions,
1350                                           sizeof(*o2hb_db_quorumregions),
1351                                           O2HB_DB_TYPE_QUORUMREGIONS,
1352                                           sizeof(o2hb_quorum_region_bitmap),
1353                                           O2NM_MAX_REGIONS,
1354                                           o2hb_quorum_region_bitmap);
1355         if (!o2hb_debug_quorumregions) {
1356                 mlog_errno(ret);
1357                 goto bail;
1358         }
1359 
1360         o2hb_debug_failedregions =
1361                         o2hb_debug_create(O2HB_DEBUG_FAILEDREGIONS,
1362                                           o2hb_debug_dir,
1363                                           &o2hb_db_failedregions,
1364                                           sizeof(*o2hb_db_failedregions),
1365                                           O2HB_DB_TYPE_FAILEDREGIONS,
1366                                           sizeof(o2hb_failed_region_bitmap),
1367                                           O2NM_MAX_REGIONS,
1368                                           o2hb_failed_region_bitmap);
1369         if (!o2hb_debug_failedregions) {
1370                 mlog_errno(ret);
1371                 goto bail;
1372         }
1373 
1374         ret = 0;
1375 bail:
1376         if (ret)
1377                 o2hb_exit();
1378 
1379         return ret;
1380 }
1381 
1382 int o2hb_init(void)
1383 {
1384         int i;
1385 
1386         for (i = 0; i < ARRAY_SIZE(o2hb_callbacks); i++)
1387                 INIT_LIST_HEAD(&o2hb_callbacks[i].list);
1388 
1389         for (i = 0; i < ARRAY_SIZE(o2hb_live_slots); i++)
1390                 INIT_LIST_HEAD(&o2hb_live_slots[i]);
1391 
1392         INIT_LIST_HEAD(&o2hb_node_events);
1393 
1394         memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
1395         memset(o2hb_region_bitmap, 0, sizeof(o2hb_region_bitmap));
1396         memset(o2hb_live_region_bitmap, 0, sizeof(o2hb_live_region_bitmap));
1397         memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
1398         memset(o2hb_failed_region_bitmap, 0, sizeof(o2hb_failed_region_bitmap));
1399 
1400         o2hb_dependent_users = 0;
1401 
1402         return o2hb_debug_init();
1403 }
1404 
1405 /* if we're already in a callback then we're already serialized by the sem */
1406 static void o2hb_fill_node_map_from_callback(unsigned long *map,
1407                                              unsigned bytes)
1408 {
1409         BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1410 
1411         memcpy(map, &o2hb_live_node_bitmap, bytes);
1412 }
1413 
1414 /*
1415  * get a map of all nodes that are heartbeating in any regions
1416  */
1417 void o2hb_fill_node_map(unsigned long *map, unsigned bytes)
1418 {
1419         /* callers want to serialize this map and callbacks so that they
1420          * can trust that they don't miss nodes coming to the party */
1421         down_read(&o2hb_callback_sem);
1422         spin_lock(&o2hb_live_lock);
1423         o2hb_fill_node_map_from_callback(map, bytes);
1424         spin_unlock(&o2hb_live_lock);
1425         up_read(&o2hb_callback_sem);
1426 }
1427 EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
1428 
1429 /*
1430  * heartbeat configfs bits.  The heartbeat set is a default set under
1431  * the cluster set in nodemanager.c.
1432  */
1433 
1434 static struct o2hb_region *to_o2hb_region(struct config_item *item)
1435 {
1436         return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
1437 }
1438 
1439 /* drop_item only drops its ref after killing the thread, nothing should
1440  * be using the region anymore.  this has to clean up any state that
1441  * attributes might have built up. */
1442 static void o2hb_region_release(struct config_item *item)
1443 {
1444         int i;
1445         struct page *page;
1446         struct o2hb_region *reg = to_o2hb_region(item);
1447 
1448         mlog(ML_HEARTBEAT, "hb region release (%s)\n", reg->hr_dev_name);
1449 
1450         kfree(reg->hr_tmp_block);
1451 
1452         if (reg->hr_slot_data) {
1453                 for (i = 0; i < reg->hr_num_pages; i++) {
1454                         page = reg->hr_slot_data[i];
1455                         if (page)
1456                                 __free_page(page);
1457                 }
1458                 kfree(reg->hr_slot_data);
1459         }
1460 
1461         if (reg->hr_bdev)
1462                 blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1463 
1464         kfree(reg->hr_slots);
1465 
1466         kfree(reg->hr_db_regnum);
1467         kfree(reg->hr_db_livenodes);
1468         debugfs_remove(reg->hr_debug_livenodes);
1469         debugfs_remove(reg->hr_debug_regnum);
1470         debugfs_remove(reg->hr_debug_elapsed_time);
1471         debugfs_remove(reg->hr_debug_pinned);
1472         debugfs_remove(reg->hr_debug_dir);
1473 
1474         spin_lock(&o2hb_live_lock);
1475         list_del(&reg->hr_all_item);
1476         spin_unlock(&o2hb_live_lock);
1477 
1478         kfree(reg);
1479 }
1480 
1481 static int o2hb_read_block_input(struct o2hb_region *reg,
1482                                  const char *page,
1483                                  size_t count,
1484                                  unsigned long *ret_bytes,
1485                                  unsigned int *ret_bits)
1486 {
1487         unsigned long bytes;
1488         char *p = (char *)page;
1489 
1490         bytes = simple_strtoul(p, &p, 0);
1491         if (!p || (*p && (*p != '\n')))
1492                 return -EINVAL;
1493 
1494         /* Heartbeat and fs min / max block sizes are the same. */
1495         if (bytes > 4096 || bytes < 512)
1496                 return -ERANGE;
1497         if (hweight16(bytes) != 1)
1498                 return -EINVAL;
1499 
1500         if (ret_bytes)
1501                 *ret_bytes = bytes;
1502         if (ret_bits)
1503                 *ret_bits = ffs(bytes) - 1;
1504 
1505         return 0;
1506 }
1507 
1508 static ssize_t o2hb_region_block_bytes_read(struct o2hb_region *reg,
1509                                             char *page)
1510 {
1511         return sprintf(page, "%u\n", reg->hr_block_bytes);
1512 }
1513 
1514 static ssize_t o2hb_region_block_bytes_write(struct o2hb_region *reg,
1515                                              const char *page,
1516                                              size_t count)
1517 {
1518         int status;
1519         unsigned long block_bytes;
1520         unsigned int block_bits;
1521 
1522         if (reg->hr_bdev)
1523                 return -EINVAL;
1524 
1525         status = o2hb_read_block_input(reg, page, count,
1526                                        &block_bytes, &block_bits);
1527         if (status)
1528                 return status;
1529 
1530         reg->hr_block_bytes = (unsigned int)block_bytes;
1531         reg->hr_block_bits = block_bits;
1532 
1533         return count;
1534 }
1535 
1536 static ssize_t o2hb_region_start_block_read(struct o2hb_region *reg,
1537                                             char *page)
1538 {
1539         return sprintf(page, "%llu\n", reg->hr_start_block);
1540 }
1541 
1542 static ssize_t o2hb_region_start_block_write(struct o2hb_region *reg,
1543                                              const char *page,
1544                                              size_t count)
1545 {
1546         unsigned long long tmp;
1547         char *p = (char *)page;
1548 
1549         if (reg->hr_bdev)
1550                 return -EINVAL;
1551 
1552         tmp = simple_strtoull(p, &p, 0);
1553         if (!p || (*p && (*p != '\n')))
1554                 return -EINVAL;
1555 
1556         reg->hr_start_block = tmp;
1557 
1558         return count;
1559 }
1560 
1561 static ssize_t o2hb_region_blocks_read(struct o2hb_region *reg,
1562                                        char *page)
1563 {
1564         return sprintf(page, "%d\n", reg->hr_blocks);
1565 }
1566 
1567 static ssize_t o2hb_region_blocks_write(struct o2hb_region *reg,
1568                                         const char *page,
1569                                         size_t count)
1570 {
1571         unsigned long tmp;
1572         char *p = (char *)page;
1573 
1574         if (reg->hr_bdev)
1575                 return -EINVAL;
1576 
1577         tmp = simple_strtoul(p, &p, 0);
1578         if (!p || (*p && (*p != '\n')))
1579                 return -EINVAL;
1580 
1581         if (tmp > O2NM_MAX_NODES || tmp == 0)
1582                 return -ERANGE;
1583 
1584         reg->hr_blocks = (unsigned int)tmp;
1585 
1586         return count;
1587 }
1588 
1589 static ssize_t o2hb_region_dev_read(struct o2hb_region *reg,
1590                                     char *page)
1591 {
1592         unsigned int ret = 0;
1593 
1594         if (reg->hr_bdev)
1595                 ret = sprintf(page, "%s\n", reg->hr_dev_name);
1596 
1597         return ret;
1598 }
1599 
1600 static void o2hb_init_region_params(struct o2hb_region *reg)
1601 {
1602         reg->hr_slots_per_page = PAGE_CACHE_SIZE >> reg->hr_block_bits;
1603         reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
1604 
1605         mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
1606              reg->hr_start_block, reg->hr_blocks);
1607         mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
1608              reg->hr_block_bytes, reg->hr_block_bits);
1609         mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
1610         mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
1611 }
1612 
1613 static int o2hb_map_slot_data(struct o2hb_region *reg)
1614 {
1615         int i, j;
1616         unsigned int last_slot;
1617         unsigned int spp = reg->hr_slots_per_page;
1618         struct page *page;
1619         char *raw;
1620         struct o2hb_disk_slot *slot;
1621 
1622         reg->hr_tmp_block = kmalloc(reg->hr_block_bytes, GFP_KERNEL);
1623         if (reg->hr_tmp_block == NULL) {
1624                 mlog_errno(-ENOMEM);
1625                 return -ENOMEM;
1626         }
1627 
1628         reg->hr_slots = kcalloc(reg->hr_blocks,
1629                                 sizeof(struct o2hb_disk_slot), GFP_KERNEL);
1630         if (reg->hr_slots == NULL) {
1631                 mlog_errno(-ENOMEM);
1632                 return -ENOMEM;
1633         }
1634 
1635         for(i = 0; i < reg->hr_blocks; i++) {
1636                 slot = &reg->hr_slots[i];
1637                 slot->ds_node_num = i;
1638                 INIT_LIST_HEAD(&slot->ds_live_item);
1639                 slot->ds_raw_block = NULL;
1640         }
1641 
1642         reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
1643         mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
1644                            "at %u blocks per page\n",
1645              reg->hr_num_pages, reg->hr_blocks, spp);
1646 
1647         reg->hr_slot_data = kcalloc(reg->hr_num_pages, sizeof(struct page *),
1648                                     GFP_KERNEL);
1649         if (!reg->hr_slot_data) {
1650                 mlog_errno(-ENOMEM);
1651                 return -ENOMEM;
1652         }
1653 
1654         for(i = 0; i < reg->hr_num_pages; i++) {
1655                 page = alloc_page(GFP_KERNEL);
1656                 if (!page) {
1657                         mlog_errno(-ENOMEM);
1658                         return -ENOMEM;
1659                 }
1660 
1661                 reg->hr_slot_data[i] = page;
1662 
1663                 last_slot = i * spp;
1664                 raw = page_address(page);
1665                 for (j = 0;
1666                      (j < spp) && ((j + last_slot) < reg->hr_blocks);
1667                      j++) {
1668                         BUG_ON((j + last_slot) >= reg->hr_blocks);
1669 
1670                         slot = &reg->hr_slots[j + last_slot];
1671                         slot->ds_raw_block =
1672                                 (struct o2hb_disk_heartbeat_block *) raw;
1673 
1674                         raw += reg->hr_block_bytes;
1675                 }
1676         }
1677 
1678         return 0;
1679 }
1680 
1681 /* Read in all the slots available and populate the tracking
1682  * structures so that we can start with a baseline idea of what's
1683  * there. */
1684 static int o2hb_populate_slot_data(struct o2hb_region *reg)
1685 {
1686         int ret, i;
1687         struct o2hb_disk_slot *slot;
1688         struct o2hb_disk_heartbeat_block *hb_block;
1689 
1690         ret = o2hb_read_slots(reg, reg->hr_blocks);
1691         if (ret) {
1692                 mlog_errno(ret);
1693                 goto out;
1694         }
1695 
1696         /* We only want to get an idea of the values initially in each
1697          * slot, so we do no verification - o2hb_check_slot will
1698          * actually determine if each configured slot is valid and
1699          * whether any values have changed. */
1700         for(i = 0; i < reg->hr_blocks; i++) {
1701                 slot = &reg->hr_slots[i];
1702                 hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
1703 
1704                 /* Only fill the values that o2hb_check_slot uses to
1705                  * determine changing slots */
1706                 slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
1707                 slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
1708         }
1709 
1710 out:
1711         return ret;
1712 }
1713 
1714 /* this is acting as commit; we set up all of hr_bdev and hr_task or nothing */
1715 static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
1716                                      const char *page,
1717                                      size_t count)
1718 {
1719         struct task_struct *hb_task;
1720         long fd;
1721         int sectsize;
1722         char *p = (char *)page;
1723         struct fd f;
1724         struct inode *inode;
1725         ssize_t ret = -EINVAL;
1726         int live_threshold;
1727 
1728         if (reg->hr_bdev)
1729                 goto out;
1730 
1731         /* We can't heartbeat without having had our node number
1732          * configured yet. */
1733         if (o2nm_this_node() == O2NM_MAX_NODES)
1734                 goto out;
1735 
1736         fd = simple_strtol(p, &p, 0);
1737         if (!p || (*p && (*p != '\n')))
1738                 goto out;
1739 
1740         if (fd < 0 || fd >= INT_MAX)
1741                 goto out;
1742 
1743         f = fdget(fd);
1744         if (f.file == NULL)
1745                 goto out;
1746 
1747         if (reg->hr_blocks == 0 || reg->hr_start_block == 0 ||
1748             reg->hr_block_bytes == 0)
1749                 goto out2;
1750 
1751         inode = igrab(f.file->f_mapping->host);
1752         if (inode == NULL)
1753                 goto out2;
1754 
1755         if (!S_ISBLK(inode->i_mode))
1756                 goto out3;
1757 
1758         reg->hr_bdev = I_BDEV(f.file->f_mapping->host);
1759         ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ, NULL);
1760         if (ret) {
1761                 reg->hr_bdev = NULL;
1762                 goto out3;
1763         }
1764         inode = NULL;
1765 
1766         bdevname(reg->hr_bdev, reg->hr_dev_name);
1767 
1768         sectsize = bdev_logical_block_size(reg->hr_bdev);
1769         if (sectsize != reg->hr_block_bytes) {
1770                 mlog(ML_ERROR,
1771                      "blocksize %u incorrect for device, expected %d",
1772                      reg->hr_block_bytes, sectsize);
1773                 ret = -EINVAL;
1774                 goto out3;
1775         }
1776 
1777         o2hb_init_region_params(reg);
1778 
1779         /* Generation of zero is invalid */
1780         do {
1781                 get_random_bytes(&reg->hr_generation,
1782                                  sizeof(reg->hr_generation));
1783         } while (reg->hr_generation == 0);
1784 
1785         ret = o2hb_map_slot_data(reg);
1786         if (ret) {
1787                 mlog_errno(ret);
1788                 goto out3;
1789         }
1790 
1791         ret = o2hb_populate_slot_data(reg);
1792         if (ret) {
1793                 mlog_errno(ret);
1794                 goto out3;
1795         }
1796 
1797         INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
1798 
1799         /*
1800          * A node is considered live after it has beat LIVE_THRESHOLD
1801          * times.  We're not steady until we've given them a chance
1802          * _after_ our first read.
1803          * The default threshold is bare minimum so as to limit the delay
1804          * during mounts. For global heartbeat, the threshold doubled for the
1805          * first region.
1806          */
1807         live_threshold = O2HB_LIVE_THRESHOLD;
1808         if (o2hb_global_heartbeat_active()) {
1809                 spin_lock(&o2hb_live_lock);
1810                 if (bitmap_weight(o2hb_region_bitmap, O2NM_MAX_REGIONS) == 1)
1811                         live_threshold <<= 1;
1812                 spin_unlock(&o2hb_live_lock);
1813         }
1814         ++live_threshold;
1815         atomic_set(&reg->hr_steady_iterations, live_threshold);
1816         /* unsteady_iterations is double the steady_iterations */
1817         atomic_set(&reg->hr_unsteady_iterations, (live_threshold << 1));
1818 
1819         hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
1820                               reg->hr_item.ci_name);
1821         if (IS_ERR(hb_task)) {
1822                 ret = PTR_ERR(hb_task);
1823                 mlog_errno(ret);
1824                 goto out3;
1825         }
1826 
1827         spin_lock(&o2hb_live_lock);
1828         reg->hr_task = hb_task;
1829         spin_unlock(&o2hb_live_lock);
1830 
1831         ret = wait_event_interruptible(o2hb_steady_queue,
1832                                 atomic_read(&reg->hr_steady_iterations) == 0);
1833         if (ret) {
1834                 atomic_set(&reg->hr_steady_iterations, 0);
1835                 reg->hr_aborted_start = 1;
1836         }
1837 
1838         if (reg->hr_aborted_start) {
1839                 ret = -EIO;
1840                 goto out3;
1841         }
1842 
1843         /* Ok, we were woken.  Make sure it wasn't by drop_item() */
1844         spin_lock(&o2hb_live_lock);
1845         hb_task = reg->hr_task;
1846         if (o2hb_global_heartbeat_active())
1847                 set_bit(reg->hr_region_num, o2hb_live_region_bitmap);
1848         spin_unlock(&o2hb_live_lock);
1849 
1850         if (hb_task)
1851                 ret = count;
1852         else
1853                 ret = -EIO;
1854 
1855         if (hb_task && o2hb_global_heartbeat_active())
1856                 printk(KERN_NOTICE "o2hb: Heartbeat started on region %s (%s)\n",
1857                        config_item_name(&reg->hr_item), reg->hr_dev_name);
1858 
1859 out3:
1860         iput(inode);
1861 out2:
1862         fdput(f);
1863 out:
1864         if (ret < 0) {
1865                 if (reg->hr_bdev) {
1866                         blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1867                         reg->hr_bdev = NULL;
1868                 }
1869         }
1870         return ret;
1871 }
1872 
1873 static ssize_t o2hb_region_pid_read(struct o2hb_region *reg,
1874                                       char *page)
1875 {
1876         pid_t pid = 0;
1877 
1878         spin_lock(&o2hb_live_lock);
1879         if (reg->hr_task)
1880                 pid = task_pid_nr(reg->hr_task);
1881         spin_unlock(&o2hb_live_lock);
1882 
1883         if (!pid)
1884                 return 0;
1885 
1886         return sprintf(page, "%u\n", pid);
1887 }
1888 
1889 struct o2hb_region_attribute {
1890         struct configfs_attribute attr;
1891         ssize_t (*show)(struct o2hb_region *, char *);
1892         ssize_t (*store)(struct o2hb_region *, const char *, size_t);
1893 };
1894 
1895 static struct o2hb_region_attribute o2hb_region_attr_block_bytes = {
1896         .attr   = { .ca_owner = THIS_MODULE,
1897                     .ca_name = "block_bytes",
1898                     .ca_mode = S_IRUGO | S_IWUSR },
1899         .show   = o2hb_region_block_bytes_read,
1900         .store  = o2hb_region_block_bytes_write,
1901 };
1902 
1903 static struct o2hb_region_attribute o2hb_region_attr_start_block = {
1904         .attr   = { .ca_owner = THIS_MODULE,
1905                     .ca_name = "start_block",
1906                     .ca_mode = S_IRUGO | S_IWUSR },
1907         .show   = o2hb_region_start_block_read,
1908         .store  = o2hb_region_start_block_write,
1909 };
1910 
1911 static struct o2hb_region_attribute o2hb_region_attr_blocks = {
1912         .attr   = { .ca_owner = THIS_MODULE,
1913                     .ca_name = "blocks",
1914                     .ca_mode = S_IRUGO | S_IWUSR },
1915         .show   = o2hb_region_blocks_read,
1916         .store  = o2hb_region_blocks_write,
1917 };
1918 
1919 static struct o2hb_region_attribute o2hb_region_attr_dev = {
1920         .attr   = { .ca_owner = THIS_MODULE,
1921                     .ca_name = "dev",
1922                     .ca_mode = S_IRUGO | S_IWUSR },
1923         .show   = o2hb_region_dev_read,
1924         .store  = o2hb_region_dev_write,
1925 };
1926 
1927 static struct o2hb_region_attribute o2hb_region_attr_pid = {
1928        .attr   = { .ca_owner = THIS_MODULE,
1929                    .ca_name = "pid",
1930                    .ca_mode = S_IRUGO | S_IRUSR },
1931        .show   = o2hb_region_pid_read,
1932 };
1933 
1934 static struct configfs_attribute *o2hb_region_attrs[] = {
1935         &o2hb_region_attr_block_bytes.attr,
1936         &o2hb_region_attr_start_block.attr,
1937         &o2hb_region_attr_blocks.attr,
1938         &o2hb_region_attr_dev.attr,
1939         &o2hb_region_attr_pid.attr,
1940         NULL,
1941 };
1942 
1943 static ssize_t o2hb_region_show(struct config_item *item,
1944                                 struct configfs_attribute *attr,
1945                                 char *page)
1946 {
1947         struct o2hb_region *reg = to_o2hb_region(item);
1948         struct o2hb_region_attribute *o2hb_region_attr =
1949                 container_of(attr, struct o2hb_region_attribute, attr);
1950         ssize_t ret = 0;
1951 
1952         if (o2hb_region_attr->show)
1953                 ret = o2hb_region_attr->show(reg, page);
1954         return ret;
1955 }
1956 
1957 static ssize_t o2hb_region_store(struct config_item *item,
1958                                  struct configfs_attribute *attr,
1959                                  const char *page, size_t count)
1960 {
1961         struct o2hb_region *reg = to_o2hb_region(item);
1962         struct o2hb_region_attribute *o2hb_region_attr =
1963                 container_of(attr, struct o2hb_region_attribute, attr);
1964         ssize_t ret = -EINVAL;
1965 
1966         if (o2hb_region_attr->store)
1967                 ret = o2hb_region_attr->store(reg, page, count);
1968         return ret;
1969 }
1970 
1971 static struct configfs_item_operations o2hb_region_item_ops = {
1972         .release                = o2hb_region_release,
1973         .show_attribute         = o2hb_region_show,
1974         .store_attribute        = o2hb_region_store,
1975 };
1976 
1977 static struct config_item_type o2hb_region_type = {
1978         .ct_item_ops    = &o2hb_region_item_ops,
1979         .ct_attrs       = o2hb_region_attrs,
1980         .ct_owner       = THIS_MODULE,
1981 };
1982 
1983 /* heartbeat set */
1984 
1985 struct o2hb_heartbeat_group {
1986         struct config_group hs_group;
1987         /* some stuff? */
1988 };
1989 
1990 static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
1991 {
1992         return group ?
1993                 container_of(group, struct o2hb_heartbeat_group, hs_group)
1994                 : NULL;
1995 }
1996 
1997 static int o2hb_debug_region_init(struct o2hb_region *reg, struct dentry *dir)
1998 {
1999         int ret = -ENOMEM;
2000 
2001         reg->hr_debug_dir =
2002                 debugfs_create_dir(config_item_name(&reg->hr_item), dir);
2003         if (!reg->hr_debug_dir) {
2004                 mlog_errno(ret);
2005                 goto bail;
2006         }
2007 
2008         reg->hr_debug_livenodes =
2009                         o2hb_debug_create(O2HB_DEBUG_LIVENODES,
2010                                           reg->hr_debug_dir,
2011                                           &(reg->hr_db_livenodes),
2012                                           sizeof(*(reg->hr_db_livenodes)),
2013                                           O2HB_DB_TYPE_REGION_LIVENODES,
2014                                           sizeof(reg->hr_live_node_bitmap),
2015                                           O2NM_MAX_NODES, reg);
2016         if (!reg->hr_debug_livenodes) {
2017                 mlog_errno(ret);
2018                 goto bail;
2019         }
2020 
2021         reg->hr_debug_regnum =
2022                         o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER,
2023                                           reg->hr_debug_dir,
2024                                           &(reg->hr_db_regnum),
2025                                           sizeof(*(reg->hr_db_regnum)),
2026                                           O2HB_DB_TYPE_REGION_NUMBER,
2027                                           0, O2NM_MAX_NODES, reg);
2028         if (!reg->hr_debug_regnum) {
2029                 mlog_errno(ret);
2030                 goto bail;
2031         }
2032 
2033         reg->hr_debug_elapsed_time =
2034                         o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME,
2035                                           reg->hr_debug_dir,
2036                                           &(reg->hr_db_elapsed_time),
2037                                           sizeof(*(reg->hr_db_elapsed_time)),
2038                                           O2HB_DB_TYPE_REGION_ELAPSED_TIME,
2039                                           0, 0, reg);
2040         if (!reg->hr_debug_elapsed_time) {
2041                 mlog_errno(ret);
2042                 goto bail;
2043         }
2044 
2045         reg->hr_debug_pinned =
2046                         o2hb_debug_create(O2HB_DEBUG_REGION_PINNED,
2047                                           reg->hr_debug_dir,
2048                                           &(reg->hr_db_pinned),
2049                                           sizeof(*(reg->hr_db_pinned)),
2050                                           O2HB_DB_TYPE_REGION_PINNED,
2051                                           0, 0, reg);
2052         if (!reg->hr_debug_pinned) {
2053                 mlog_errno(ret);
2054                 goto bail;
2055         }
2056 
2057         ret = 0;
2058 bail:
2059         return ret;
2060 }
2061 
2062 static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
2063                                                           const char *name)
2064 {
2065         struct o2hb_region *reg = NULL;
2066         int ret;
2067 
2068         reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
2069         if (reg == NULL)
2070                 return ERR_PTR(-ENOMEM);
2071 
2072         if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
2073                 ret = -ENAMETOOLONG;
2074                 goto free;
2075         }
2076 
2077         spin_lock(&o2hb_live_lock);
2078         reg->hr_region_num = 0;
2079         if (o2hb_global_heartbeat_active()) {
2080                 reg->hr_region_num = find_first_zero_bit(o2hb_region_bitmap,
2081                                                          O2NM_MAX_REGIONS);
2082                 if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
2083                         spin_unlock(&o2hb_live_lock);
2084                         ret = -EFBIG;
2085                         goto free;
2086                 }
2087                 set_bit(reg->hr_region_num, o2hb_region_bitmap);
2088         }
2089         list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
2090         spin_unlock(&o2hb_live_lock);
2091 
2092         config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
2093 
2094         ret = o2hb_debug_region_init(reg, o2hb_debug_dir);
2095         if (ret) {
2096                 config_item_put(&reg->hr_item);
2097                 goto free;
2098         }
2099 
2100         return &reg->hr_item;
2101 free:
2102         kfree(reg);
2103         return ERR_PTR(ret);
2104 }
2105 
2106 static void o2hb_heartbeat_group_drop_item(struct config_group *group,
2107                                            struct config_item *item)
2108 {
2109         struct task_struct *hb_task;
2110         struct o2hb_region *reg = to_o2hb_region(item);
2111         int quorum_region = 0;
2112 
2113         /* stop the thread when the user removes the region dir */
2114         spin_lock(&o2hb_live_lock);
2115         hb_task = reg->hr_task;
2116         reg->hr_task = NULL;
2117         reg->hr_item_dropped = 1;
2118         spin_unlock(&o2hb_live_lock);
2119 
2120         if (hb_task)
2121                 kthread_stop(hb_task);
2122 
2123         if (o2hb_global_heartbeat_active()) {
2124                 spin_lock(&o2hb_live_lock);
2125                 clear_bit(reg->hr_region_num, o2hb_region_bitmap);
2126                 clear_bit(reg->hr_region_num, o2hb_live_region_bitmap);
2127                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
2128                         quorum_region = 1;
2129                 clear_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
2130                 spin_unlock(&o2hb_live_lock);
2131                 printk(KERN_NOTICE "o2hb: Heartbeat %s on region %s (%s)\n",
2132                        ((atomic_read(&reg->hr_steady_iterations) == 0) ?
2133                         "stopped" : "start aborted"), config_item_name(item),
2134                        reg->hr_dev_name);
2135         }
2136 
2137         /*
2138          * If we're racing a dev_write(), we need to wake them.  They will
2139          * check reg->hr_task
2140          */
2141         if (atomic_read(&reg->hr_steady_iterations) != 0) {
2142                 reg->hr_aborted_start = 1;
2143                 atomic_set(&reg->hr_steady_iterations, 0);
2144                 wake_up(&o2hb_steady_queue);
2145         }
2146 
2147         config_item_put(item);
2148 
2149         if (!o2hb_global_heartbeat_active() || !quorum_region)
2150                 return;
2151 
2152         /*
2153          * If global heartbeat active and there are dependent users,
2154          * pin all regions if quorum region count <= CUT_OFF
2155          */
2156         spin_lock(&o2hb_live_lock);
2157 
2158         if (!o2hb_dependent_users)
2159                 goto unlock;
2160 
2161         if (bitmap_weight(o2hb_quorum_region_bitmap,
2162                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2163                 o2hb_region_pin(NULL);
2164 
2165 unlock:
2166         spin_unlock(&o2hb_live_lock);
2167 }
2168 
2169 struct o2hb_heartbeat_group_attribute {
2170         struct configfs_attribute attr;
2171         ssize_t (*show)(struct o2hb_heartbeat_group *, char *);
2172         ssize_t (*store)(struct o2hb_heartbeat_group *, const char *, size_t);
2173 };
2174 
2175 static ssize_t o2hb_heartbeat_group_show(struct config_item *item,
2176                                          struct configfs_attribute *attr,
2177                                          char *page)
2178 {
2179         struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
2180         struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
2181                 container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
2182         ssize_t ret = 0;
2183 
2184         if (o2hb_heartbeat_group_attr->show)
2185                 ret = o2hb_heartbeat_group_attr->show(reg, page);
2186         return ret;
2187 }
2188 
2189 static ssize_t o2hb_heartbeat_group_store(struct config_item *item,
2190                                           struct configfs_attribute *attr,
2191                                           const char *page, size_t count)
2192 {
2193         struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
2194         struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
2195                 container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
2196         ssize_t ret = -EINVAL;
2197 
2198         if (o2hb_heartbeat_group_attr->store)
2199                 ret = o2hb_heartbeat_group_attr->store(reg, page, count);
2200         return ret;
2201 }
2202 
2203 static ssize_t o2hb_heartbeat_group_threshold_show(struct o2hb_heartbeat_group *group,
2204                                                      char *page)
2205 {
2206         return sprintf(page, "%u\n", o2hb_dead_threshold);
2207 }
2208 
2209 static ssize_t o2hb_heartbeat_group_threshold_store(struct o2hb_heartbeat_group *group,
2210                                                     const char *page,
2211                                                     size_t count)
2212 {
2213         unsigned long tmp;
2214         char *p = (char *)page;
2215 
2216         tmp = simple_strtoul(p, &p, 10);
2217         if (!p || (*p && (*p != '\n')))
2218                 return -EINVAL;
2219 
2220         /* this will validate ranges for us. */
2221         o2hb_dead_threshold_set((unsigned int) tmp);
2222 
2223         return count;
2224 }
2225 
2226 static
2227 ssize_t o2hb_heartbeat_group_mode_show(struct o2hb_heartbeat_group *group,
2228                                        char *page)
2229 {
2230         return sprintf(page, "%s\n",
2231                        o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
2232 }
2233 
2234 static
2235 ssize_t o2hb_heartbeat_group_mode_store(struct o2hb_heartbeat_group *group,
2236                                         const char *page, size_t count)
2237 {
2238         unsigned int i;
2239         int ret;
2240         size_t len;
2241 
2242         len = (page[count - 1] == '\n') ? count - 1 : count;
2243         if (!len)
2244                 return -EINVAL;
2245 
2246         for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
2247                 if (strncasecmp(page, o2hb_heartbeat_mode_desc[i], len))
2248                         continue;
2249 
2250                 ret = o2hb_global_heartbeat_mode_set(i);
2251                 if (!ret)
2252                         printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
2253                                o2hb_heartbeat_mode_desc[i]);
2254                 return count;
2255         }
2256 
2257         return -EINVAL;
2258 
2259 }
2260 
2261 static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_threshold = {
2262         .attr   = { .ca_owner = THIS_MODULE,
2263                     .ca_name = "dead_threshold",
2264                     .ca_mode = S_IRUGO | S_IWUSR },
2265         .show   = o2hb_heartbeat_group_threshold_show,
2266         .store  = o2hb_heartbeat_group_threshold_store,
2267 };
2268 
2269 static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_mode = {
2270         .attr   = { .ca_owner = THIS_MODULE,
2271                 .ca_name = "mode",
2272                 .ca_mode = S_IRUGO | S_IWUSR },
2273         .show   = o2hb_heartbeat_group_mode_show,
2274         .store  = o2hb_heartbeat_group_mode_store,
2275 };
2276 
2277 static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
2278         &o2hb_heartbeat_group_attr_threshold.attr,
2279         &o2hb_heartbeat_group_attr_mode.attr,
2280         NULL,
2281 };
2282 
2283 static struct configfs_item_operations o2hb_heartbeat_group_item_ops = {
2284         .show_attribute         = o2hb_heartbeat_group_show,
2285         .store_attribute        = o2hb_heartbeat_group_store,
2286 };
2287 
2288 static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
2289         .make_item      = o2hb_heartbeat_group_make_item,
2290         .drop_item      = o2hb_heartbeat_group_drop_item,
2291 };
2292 
2293 static struct config_item_type o2hb_heartbeat_group_type = {
2294         .ct_group_ops   = &o2hb_heartbeat_group_group_ops,
2295         .ct_item_ops    = &o2hb_heartbeat_group_item_ops,
2296         .ct_attrs       = o2hb_heartbeat_group_attrs,
2297         .ct_owner       = THIS_MODULE,
2298 };
2299 
2300 /* this is just here to avoid touching group in heartbeat.h which the
2301  * entire damn world #includes */
2302 struct config_group *o2hb_alloc_hb_set(void)
2303 {
2304         struct o2hb_heartbeat_group *hs = NULL;
2305         struct config_group *ret = NULL;
2306 
2307         hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
2308         if (hs == NULL)
2309                 goto out;
2310 
2311         config_group_init_type_name(&hs->hs_group, "heartbeat",
2312                                     &o2hb_heartbeat_group_type);
2313 
2314         ret = &hs->hs_group;
2315 out:
2316         if (ret == NULL)
2317                 kfree(hs);
2318         return ret;
2319 }
2320 
2321 void o2hb_free_hb_set(struct config_group *group)
2322 {
2323         struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
2324         kfree(hs);
2325 }
2326 
2327 /* hb callback registration and issuing */
2328 
2329 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
2330 {
2331         if (type == O2HB_NUM_CB)
2332                 return ERR_PTR(-EINVAL);
2333 
2334         return &o2hb_callbacks[type];
2335 }
2336 
2337 void o2hb_setup_callback(struct o2hb_callback_func *hc,
2338                          enum o2hb_callback_type type,
2339                          o2hb_cb_func *func,
2340                          void *data,
2341                          int priority)
2342 {
2343         INIT_LIST_HEAD(&hc->hc_item);
2344         hc->hc_func = func;
2345         hc->hc_data = data;
2346         hc->hc_priority = priority;
2347         hc->hc_type = type;
2348         hc->hc_magic = O2HB_CB_MAGIC;
2349 }
2350 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
2351 
2352 /*
2353  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2354  * In global heartbeat mode, region_uuid passed is NULL.
2355  *
2356  * In local, we only pin the matching region. In global we pin all the active
2357  * regions.
2358  */
2359 static int o2hb_region_pin(const char *region_uuid)
2360 {
2361         int ret = 0, found = 0;
2362         struct o2hb_region *reg;
2363         char *uuid;
2364 
2365         assert_spin_locked(&o2hb_live_lock);
2366 
2367         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2368                 if (reg->hr_item_dropped)
2369                         continue;
2370 
2371                 uuid = config_item_name(&reg->hr_item);
2372 
2373                 /* local heartbeat */
2374                 if (region_uuid) {
2375                         if (strcmp(region_uuid, uuid))
2376                                 continue;
2377                         found = 1;
2378                 }
2379 
2380                 if (reg->hr_item_pinned || reg->hr_item_dropped)
2381                         goto skip_pin;
2382 
2383                 /* Ignore ENOENT only for local hb (userdlm domain) */
2384                 ret = o2nm_depend_item(&reg->hr_item);
2385                 if (!ret) {
2386                         mlog(ML_CLUSTER, "Pin region %s\n", uuid);
2387                         reg->hr_item_pinned = 1;
2388                 } else {
2389                         if (ret == -ENOENT && found)
2390                                 ret = 0;
2391                         else {
2392                                 mlog(ML_ERROR, "Pin region %s fails with %d\n",
2393                                      uuid, ret);
2394                                 break;
2395                         }
2396                 }
2397 skip_pin:
2398                 if (found)
2399                         break;
2400         }
2401 
2402         return ret;
2403 }
2404 
2405 /*
2406  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2407  * In global heartbeat mode, region_uuid passed is NULL.
2408  *
2409  * In local, we only unpin the matching region. In global we unpin all the
2410  * active regions.
2411  */
2412 static void o2hb_region_unpin(const char *region_uuid)
2413 {
2414         struct o2hb_region *reg;
2415         char *uuid;
2416         int found = 0;
2417 
2418         assert_spin_locked(&o2hb_live_lock);
2419 
2420         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2421                 if (reg->hr_item_dropped)
2422                         continue;
2423 
2424                 uuid = config_item_name(&reg->hr_item);
2425                 if (region_uuid) {
2426                         if (strcmp(region_uuid, uuid))
2427                                 continue;
2428                         found = 1;
2429                 }
2430 
2431                 if (reg->hr_item_pinned) {
2432                         mlog(ML_CLUSTER, "Unpin region %s\n", uuid);
2433                         o2nm_undepend_item(&reg->hr_item);
2434                         reg->hr_item_pinned = 0;
2435                 }
2436                 if (found)
2437                         break;
2438         }
2439 }
2440 
2441 static int o2hb_region_inc_user(const char *region_uuid)
2442 {
2443         int ret = 0;
2444 
2445         spin_lock(&o2hb_live_lock);
2446 
2447         /* local heartbeat */
2448         if (!o2hb_global_heartbeat_active()) {
2449             ret = o2hb_region_pin(region_uuid);
2450             goto unlock;
2451         }
2452 
2453         /*
2454          * if global heartbeat active and this is the first dependent user,
2455          * pin all regions if quorum region count <= CUT_OFF
2456          */
2457         o2hb_dependent_users++;
2458         if (o2hb_dependent_users > 1)
2459                 goto unlock;
2460 
2461         if (bitmap_weight(o2hb_quorum_region_bitmap,
2462                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2463                 ret = o2hb_region_pin(NULL);
2464 
2465 unlock:
2466         spin_unlock(&o2hb_live_lock);
2467         return ret;
2468 }
2469 
2470 void o2hb_region_dec_user(const char *region_uuid)
2471 {
2472         spin_lock(&o2hb_live_lock);
2473 
2474         /* local heartbeat */
2475         if (!o2hb_global_heartbeat_active()) {
2476             o2hb_region_unpin(region_uuid);
2477             goto unlock;
2478         }
2479 
2480         /*
2481          * if global heartbeat active and there are no dependent users,
2482          * unpin all quorum regions
2483          */
2484         o2hb_dependent_users--;
2485         if (!o2hb_dependent_users)
2486                 o2hb_region_unpin(NULL);
2487 
2488 unlock:
2489         spin_unlock(&o2hb_live_lock);
2490 }
2491 
2492 int o2hb_register_callback(const char *region_uuid,
2493                            struct o2hb_callback_func *hc)
2494 {
2495         struct o2hb_callback_func *f;
2496         struct o2hb_callback *hbcall;
2497         int ret;
2498 
2499         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2500         BUG_ON(!list_empty(&hc->hc_item));
2501 
2502         hbcall = hbcall_from_type(hc->hc_type);
2503         if (IS_ERR(hbcall)) {
2504                 ret = PTR_ERR(hbcall);
2505                 goto out;
2506         }
2507 
2508         if (region_uuid) {
2509                 ret = o2hb_region_inc_user(region_uuid);
2510                 if (ret) {
2511                         mlog_errno(ret);
2512                         goto out;
2513                 }
2514         }
2515 
2516         down_write(&o2hb_callback_sem);
2517 
2518         list_for_each_entry(f, &hbcall->list, hc_item) {
2519                 if (hc->hc_priority < f->hc_priority) {
2520                         list_add_tail(&hc->hc_item, &f->hc_item);
2521                         break;
2522                 }
2523         }
2524         if (list_empty(&hc->hc_item))
2525                 list_add_tail(&hc->hc_item, &hbcall->list);
2526 
2527         up_write(&o2hb_callback_sem);
2528         ret = 0;
2529 out:
2530         mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
2531              ret, __builtin_return_address(0), hc);
2532         return ret;
2533 }
2534 EXPORT_SYMBOL_GPL(o2hb_register_callback);
2535 
2536 void o2hb_unregister_callback(const char *region_uuid,
2537                               struct o2hb_callback_func *hc)
2538 {
2539         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2540 
2541         mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
2542              __builtin_return_address(0), hc);
2543 
2544         /* XXX Can this happen _with_ a region reference? */
2545         if (list_empty(&hc->hc_item))
2546                 return;
2547 
2548         if (region_uuid)
2549                 o2hb_region_dec_user(region_uuid);
2550 
2551         down_write(&o2hb_callback_sem);
2552 
2553         list_del_init(&hc->hc_item);
2554 
2555         up_write(&o2hb_callback_sem);
2556 }
2557 EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
2558 
2559 int o2hb_check_node_heartbeating(u8 node_num)
2560 {
2561         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2562 
2563         o2hb_fill_node_map(testing_map, sizeof(testing_map));
2564         if (!test_bit(node_num, testing_map)) {
2565                 mlog(ML_HEARTBEAT,
2566                      "node (%u) does not have heartbeating enabled.\n",
2567                      node_num);
2568                 return 0;
2569         }
2570 
2571         return 1;
2572 }
2573 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating);
2574 
2575 int o2hb_check_node_heartbeating_no_sem(u8 node_num)
2576 {
2577         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2578         unsigned long flags;
2579 
2580         spin_lock_irqsave(&o2hb_live_lock, flags);
2581         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2582         spin_unlock_irqrestore(&o2hb_live_lock, flags);
2583         if (!test_bit(node_num, testing_map)) {
2584                 mlog(ML_HEARTBEAT,
2585                      "node (%u) does not have heartbeating enabled.\n",
2586                      node_num);
2587                 return 0;
2588         }
2589 
2590         return 1;
2591 }
2592 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_no_sem);
2593 
2594 int o2hb_check_node_heartbeating_from_callback(u8 node_num)
2595 {
2596         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2597 
2598         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2599         if (!test_bit(node_num, testing_map)) {
2600                 mlog(ML_HEARTBEAT,
2601                      "node (%u) does not have heartbeating enabled.\n",
2602                      node_num);
2603                 return 0;
2604         }
2605 
2606         return 1;
2607 }
2608 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_from_callback);
2609 
2610 /* Makes sure our local node is configured with a node number, and is
2611  * heartbeating. */
2612 int o2hb_check_local_node_heartbeating(void)
2613 {
2614         u8 node_num;
2615 
2616         /* if this node was set then we have networking */
2617         node_num = o2nm_this_node();
2618         if (node_num == O2NM_MAX_NODES) {
2619                 mlog(ML_HEARTBEAT, "this node has not been configured.\n");
2620                 return 0;
2621         }
2622 
2623         return o2hb_check_node_heartbeating(node_num);
2624 }
2625 EXPORT_SYMBOL_GPL(o2hb_check_local_node_heartbeating);
2626 
2627 /*
2628  * this is just a hack until we get the plumbing which flips file systems
2629  * read only and drops the hb ref instead of killing the node dead.
2630  */
2631 void o2hb_stop_all_regions(void)
2632 {
2633         struct o2hb_region *reg;
2634 
2635         mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");
2636 
2637         spin_lock(&o2hb_live_lock);
2638 
2639         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
2640                 reg->hr_unclean_stop = 1;
2641 
2642         spin_unlock(&o2hb_live_lock);
2643 }
2644 EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
2645 
2646 int o2hb_get_all_regions(char *region_uuids, u8 max_regions)
2647 {
2648         struct o2hb_region *reg;
2649         int numregs = 0;
2650         char *p;
2651 
2652         spin_lock(&o2hb_live_lock);
2653 
2654         p = region_uuids;
2655         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2656                 if (reg->hr_item_dropped)
2657                         continue;
2658 
2659                 mlog(0, "Region: %s\n", config_item_name(&reg->hr_item));
2660                 if (numregs < max_regions) {
2661                         memcpy(p, config_item_name(&reg->hr_item),
2662                                O2HB_MAX_REGION_NAME_LEN);
2663                         p += O2HB_MAX_REGION_NAME_LEN;
2664                 }
2665                 numregs++;
2666         }
2667 
2668         spin_unlock(&o2hb_live_lock);
2669 
2670         return numregs;
2671 }
2672 EXPORT_SYMBOL_GPL(o2hb_get_all_regions);
2673 
2674 int o2hb_global_heartbeat_active(void)
2675 {
2676         return (o2hb_heartbeat_mode == O2HB_HEARTBEAT_GLOBAL);
2677 }
2678 EXPORT_SYMBOL(o2hb_global_heartbeat_active);
2679 

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