fs/ocfs2/cluster/heartbeat.c

   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 #include <linux/ktime.h>
  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                                 hr_node_deleted:1;
 224
 225         /* protected by the hr_callback_sem */
 226         struct task_struct      *hr_task;
 227
 228         unsigned int            hr_blocks;
 229         unsigned long long      hr_start_block;
 230
 231         unsigned int            hr_block_bits;
 232         unsigned int            hr_block_bytes;
 233
 234         unsigned int            hr_slots_per_page;
 235         unsigned int            hr_num_pages;
 236
 237         struct page             **hr_slot_data;
 238         struct block_device     *hr_bdev;
 239         struct o2hb_disk_slot   *hr_slots;
 240
 241         /* live node map of this region */
 242         unsigned long           hr_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 243         unsigned int            hr_region_num;
 244
 245         struct dentry           *hr_debug_dir;
 246         struct dentry           *hr_debug_livenodes;
 247         struct dentry           *hr_debug_regnum;
 248         struct dentry           *hr_debug_elapsed_time;
 249         struct dentry           *hr_debug_pinned;
 250         struct o2hb_debug_buf   *hr_db_livenodes;
 251         struct o2hb_debug_buf   *hr_db_regnum;
 252         struct o2hb_debug_buf   *hr_db_elapsed_time;
 253         struct o2hb_debug_buf   *hr_db_pinned;
 254
 255         /* let the person setting up hb wait for it to return until it
 256          * has reached a 'steady' state.  This will be fixed when we have
 257          * a more complete api that doesn't lead to this sort of fragility. */
 258         atomic_t                hr_steady_iterations;
 259
 260         /* terminate o2hb thread if it does not reach steady state
 261          * (hr_steady_iterations == 0) within hr_unsteady_iterations */
 262         atomic_t                hr_unsteady_iterations;
 263
 264         char                    hr_dev_name[BDEVNAME_SIZE];
 265
 266         unsigned int            hr_timeout_ms;
 267
 268         /* randomized as the region goes up and down so that a node
 269          * recognizes a node going up and down in one iteration */
 270         u64                     hr_generation;
 271
 272         struct delayed_work     hr_write_timeout_work;
 273         unsigned long           hr_last_timeout_start;
 274
 275         /* Used during o2hb_check_slot to hold a copy of the block
 276          * being checked because we temporarily have to zero out the
 277          * crc field. */
 278         struct o2hb_disk_heartbeat_block *hr_tmp_block;
 279 };
 280
 281 struct o2hb_bio_wait_ctxt {
 282         atomic_t          wc_num_reqs;
 283         struct completion wc_io_complete;
 284         int               wc_error;
 285 };
 286
 287 static void o2hb_write_timeout(struct work_struct *work)
 288 {
 289         int failed, quorum;
 290         unsigned long flags;
 291         struct o2hb_region *reg =
 292                 container_of(work, struct o2hb_region,
 293                              hr_write_timeout_work.work);
 294
 295         mlog(ML_ERROR, "Heartbeat write timeout to device %s after %u "
 296              "milliseconds\n", reg->hr_dev_name,
 297              jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
 298
 299         if (o2hb_global_heartbeat_active()) {
 300                 spin_lock_irqsave(&o2hb_live_lock, flags);
 301                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 302                         set_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 303                 failed = bitmap_weight(o2hb_failed_region_bitmap,
 304                                         O2NM_MAX_REGIONS);
 305                 quorum = bitmap_weight(o2hb_quorum_region_bitmap,
 306                                         O2NM_MAX_REGIONS);
 307                 spin_unlock_irqrestore(&o2hb_live_lock, flags);
 308
 309                 mlog(ML_HEARTBEAT, "Number of regions %d, failed regions %d\n",
 310                      quorum, failed);
 311
 312                 /*
 313                  * Fence if the number of failed regions >= half the number
 314                  * of  quorum regions
 315                  */
 316                 if ((failed << 1) < quorum)
 317                         return;
 318         }
 319
 320         o2quo_disk_timeout();
 321 }
 322
 323 static void o2hb_arm_write_timeout(struct o2hb_region *reg)
 324 {
 325         /* Arm writeout only after thread reaches steady state */
 326         if (atomic_read(&reg->hr_steady_iterations) != 0)
 327                 return;
 328
 329         mlog(ML_HEARTBEAT, "Queue write timeout for %u ms\n",
 330              O2HB_MAX_WRITE_TIMEOUT_MS);
 331
 332         if (o2hb_global_heartbeat_active()) {
 333                 spin_lock(&o2hb_live_lock);
 334                 clear_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 335                 spin_unlock(&o2hb_live_lock);
 336         }
 337         cancel_delayed_work(&reg->hr_write_timeout_work);
 338         reg->hr_last_timeout_start = jiffies;
 339         schedule_delayed_work(&reg->hr_write_timeout_work,
 340                               msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
 341 }
 342
 343 static void o2hb_disarm_write_timeout(struct o2hb_region *reg)
 344 {
 345         cancel_delayed_work_sync(&reg->hr_write_timeout_work);
 346 }
 347
 348 static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
 349 {
 350         atomic_set(&wc->wc_num_reqs, 1);
 351         init_completion(&wc->wc_io_complete);
 352         wc->wc_error = 0;
 353 }
 354
 355 /* Used in error paths too */
 356 static inline void o2hb_bio_wait_dec(struct o2hb_bio_wait_ctxt *wc,
 357                                      unsigned int num)
 358 {
 359         /* sadly atomic_sub_and_test() isn't available on all platforms.  The
 360          * good news is that the fast path only completes one at a time */
 361         while(num--) {
 362                 if (atomic_dec_and_test(&wc->wc_num_reqs)) {
 363                         BUG_ON(num > 0);
 364                         complete(&wc->wc_io_complete);
 365                 }
 366         }
 367 }
 368
 369 static void o2hb_wait_on_io(struct o2hb_region *reg,
 370                             struct o2hb_bio_wait_ctxt *wc)
 371 {
 372         o2hb_bio_wait_dec(wc, 1);
 373         wait_for_completion(&wc->wc_io_complete);
 374 }
 375
 376 static void o2hb_bio_end_io(struct bio *bio)
 377 {
 378         struct o2hb_bio_wait_ctxt *wc = bio->bi_private;
 379
 380         if (bio->bi_error) {
 381                 mlog(ML_ERROR, "IO Error %d\n", bio->bi_error);
 382                 wc->wc_error = bio->bi_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 /*
1065  * we ride the region ref that the region dir holds.  before the region
1066  * dir is removed and drops it ref it will wait to tear down this
1067  * thread.
1068  */
1069 static int o2hb_thread(void *data)
1070 {
1071         int i, ret;
1072         struct o2hb_region *reg = data;
1073         struct o2hb_bio_wait_ctxt write_wc;
1074         ktime_t before_hb, after_hb;
1075         unsigned int elapsed_msec;
1076
1077         mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n");
1078
1079         set_user_nice(current, MIN_NICE);
1080
1081         /* Pin node */
1082         ret = o2nm_depend_this_node();
1083         if (ret) {
1084                 mlog(ML_ERROR, "Node has been deleted, ret = %d\n", ret);
1085                 reg->hr_node_deleted = 1;
1086                 wake_up(&o2hb_steady_queue);
1087                 return 0;
1088         }
1089
1090         while (!kthread_should_stop() &&
1091                !reg->hr_unclean_stop && !reg->hr_aborted_start) {
1092                 /* We track the time spent inside
1093                  * o2hb_do_disk_heartbeat so that we avoid more than
1094                  * hr_timeout_ms between disk writes. On busy systems
1095                  * this should result in a heartbeat which is less
1096                  * likely to time itself out. */
1097                 before_hb = ktime_get_real();
1098
1099                 ret = o2hb_do_disk_heartbeat(reg);
1100
1101                 after_hb = ktime_get_real();
1102
1103                 elapsed_msec = (unsigned int)
1104                                 ktime_ms_delta(after_hb, before_hb);
1105
1106                 mlog(ML_HEARTBEAT,
1107                      "start = %lld, end = %lld, msec = %u, ret = %d\n",
1108                      before_hb.tv64, after_hb.tv64, elapsed_msec, ret);
1109
1110                 if (!kthread_should_stop() &&
1111                     elapsed_msec < reg->hr_timeout_ms) {
1112                         /* the kthread api has blocked signals for us so no
1113                          * need to record the return value. */
1114                         msleep_interruptible(reg->hr_timeout_ms - elapsed_msec);
1115                 }
1116         }
1117
1118         o2hb_disarm_write_timeout(reg);
1119
1120         /* unclean stop is only used in very bad situation */
1121         for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
1122                 o2hb_shutdown_slot(&reg->hr_slots[i]);
1123
1124         /* Explicit down notification - avoid forcing the other nodes
1125          * to timeout on this region when we could just as easily
1126          * write a clear generation - thus indicating to them that
1127          * this node has left this region.
1128          */
1129         if (!reg->hr_unclean_stop && !reg->hr_aborted_start) {
1130                 o2hb_prepare_block(reg, 0);
1131                 ret = o2hb_issue_node_write(reg, &write_wc);
1132                 if (ret == 0)
1133                         o2hb_wait_on_io(reg, &write_wc);
1134                 else
1135                         mlog_errno(ret);
1136         }
1137
1138         /* Unpin node */
1139         o2nm_undepend_this_node();
1140
1141         mlog(ML_HEARTBEAT|ML_KTHREAD, "o2hb thread exiting\n");
1142
1143         return 0;
1144 }
1145
1146 #ifdef CONFIG_DEBUG_FS
1147 static int o2hb_debug_open(struct inode *inode, struct file *file)
1148 {
1149         struct o2hb_debug_buf *db = inode->i_private;
1150         struct o2hb_region *reg;
1151         unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1152         unsigned long lts;
1153         char *buf = NULL;
1154         int i = -1;
1155         int out = 0;
1156
1157         /* max_nodes should be the largest bitmap we pass here */
1158         BUG_ON(sizeof(map) < db->db_size);
1159
1160         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1161         if (!buf)
1162                 goto bail;
1163
1164         switch (db->db_type) {
1165         case O2HB_DB_TYPE_LIVENODES:
1166         case O2HB_DB_TYPE_LIVEREGIONS:
1167         case O2HB_DB_TYPE_QUORUMREGIONS:
1168         case O2HB_DB_TYPE_FAILEDREGIONS:
1169                 spin_lock(&o2hb_live_lock);
1170                 memcpy(map, db->db_data, db->db_size);
1171                 spin_unlock(&o2hb_live_lock);
1172                 break;
1173
1174         case O2HB_DB_TYPE_REGION_LIVENODES:
1175                 spin_lock(&o2hb_live_lock);
1176                 reg = (struct o2hb_region *)db->db_data;
1177                 memcpy(map, reg->hr_live_node_bitmap, db->db_size);
1178                 spin_unlock(&o2hb_live_lock);
1179                 break;
1180
1181         case O2HB_DB_TYPE_REGION_NUMBER:
1182                 reg = (struct o2hb_region *)db->db_data;
1183                 out += snprintf(buf + out, PAGE_SIZE - out, "%d\n",
1184                                 reg->hr_region_num);
1185                 goto done;
1186
1187         case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
1188                 reg = (struct o2hb_region *)db->db_data;
1189                 lts = reg->hr_last_timeout_start;
1190                 /* If 0, it has never been set before */
1191                 if (lts)
1192                         lts = jiffies_to_msecs(jiffies - lts);
1193                 out += snprintf(buf + out, PAGE_SIZE - out, "%lu\n", lts);
1194                 goto done;
1195
1196         case O2HB_DB_TYPE_REGION_PINNED:
1197                 reg = (struct o2hb_region *)db->db_data;
1198                 out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
1199                                 !!reg->hr_item_pinned);
1200                 goto done;
1201
1202         default:
1203                 goto done;
1204         }
1205
1206         while ((i = find_next_bit(map, db->db_len, i + 1)) < db->db_len)
1207                 out += snprintf(buf + out, PAGE_SIZE - out, "%d ", i);
1208         out += snprintf(buf + out, PAGE_SIZE - out, "\n");
1209
1210 done:
1211         i_size_write(inode, out);
1212
1213         file->private_data = buf;
1214
1215         return 0;
1216 bail:
1217         return -ENOMEM;
1218 }
1219
1220 static int o2hb_debug_release(struct inode *inode, struct file *file)
1221 {
1222         kfree(file->private_data);
1223         return 0;
1224 }
1225
1226 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1227                                  size_t nbytes, loff_t *ppos)
1228 {
1229         return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
1230                                        i_size_read(file->f_mapping->host));
1231 }
1232 #else
1233 static int o2hb_debug_open(struct inode *inode, struct file *file)
1234 {
1235         return 0;
1236 }
1237 static int o2hb_debug_release(struct inode *inode, struct file *file)
1238 {
1239         return 0;
1240 }
1241 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1242                                size_t nbytes, loff_t *ppos)
1243 {
1244         return 0;
1245 }
1246 #endif  /* CONFIG_DEBUG_FS */
1247
1248 static const struct file_operations o2hb_debug_fops = {
1249         .open =         o2hb_debug_open,
1250         .release =      o2hb_debug_release,
1251         .read =         o2hb_debug_read,
1252         .llseek =       generic_file_llseek,
1253 };
1254
1255 void o2hb_exit(void)
1256 {
1257         kfree(o2hb_db_livenodes);
1258         kfree(o2hb_db_liveregions);
1259         kfree(o2hb_db_quorumregions);
1260         kfree(o2hb_db_failedregions);
1261         debugfs_remove(o2hb_debug_failedregions);
1262         debugfs_remove(o2hb_debug_quorumregions);
1263         debugfs_remove(o2hb_debug_liveregions);
1264         debugfs_remove(o2hb_debug_livenodes);
1265         debugfs_remove(o2hb_debug_dir);
1266 }
1267
1268 static struct dentry *o2hb_debug_create(const char *name, struct dentry *dir,
1269                                         struct o2hb_debug_buf **db, int db_len,
1270                                         int type, int size, int len, void *data)
1271 {
1272         *db = kmalloc(db_len, GFP_KERNEL);
1273         if (!*db)
1274                 return NULL;
1275
1276         (*db)->db_type = type;
1277         (*db)->db_size = size;
1278         (*db)->db_len = len;
1279         (*db)->db_data = data;
1280
1281         return debugfs_create_file(name, S_IFREG|S_IRUSR, dir, *db,
1282                                    &o2hb_debug_fops);
1283 }
1284
1285 static int o2hb_debug_init(void)
1286 {
1287         int ret = -ENOMEM;
1288
1289         o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
1290         if (!o2hb_debug_dir) {
1291                 mlog_errno(ret);
1292                 goto bail;
1293         }
1294
1295         o2hb_debug_livenodes = o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1296                                                  o2hb_debug_dir,
1297                                                  &o2hb_db_livenodes,
1298                                                  sizeof(*o2hb_db_livenodes),
1299                                                  O2HB_DB_TYPE_LIVENODES,
1300                                                  sizeof(o2hb_live_node_bitmap),
1301                                                  O2NM_MAX_NODES,
1302                                                  o2hb_live_node_bitmap);
1303         if (!o2hb_debug_livenodes) {
1304                 mlog_errno(ret);
1305                 goto bail;
1306         }
1307
1308         o2hb_debug_liveregions = o2hb_debug_create(O2HB_DEBUG_LIVEREGIONS,
1309                                                    o2hb_debug_dir,
1310                                                    &o2hb_db_liveregions,
1311                                                    sizeof(*o2hb_db_liveregions),
1312                                                    O2HB_DB_TYPE_LIVEREGIONS,
1313                                                    sizeof(o2hb_live_region_bitmap),
1314                                                    O2NM_MAX_REGIONS,
1315                                                    o2hb_live_region_bitmap);
1316         if (!o2hb_debug_liveregions) {
1317                 mlog_errno(ret);
1318                 goto bail;
1319         }
1320
1321         o2hb_debug_quorumregions =
1322                         o2hb_debug_create(O2HB_DEBUG_QUORUMREGIONS,
1323                                           o2hb_debug_dir,
1324                                           &o2hb_db_quorumregions,
1325                                           sizeof(*o2hb_db_quorumregions),
1326                                           O2HB_DB_TYPE_QUORUMREGIONS,
1327                                           sizeof(o2hb_quorum_region_bitmap),
1328                                           O2NM_MAX_REGIONS,
1329                                           o2hb_quorum_region_bitmap);
1330         if (!o2hb_debug_quorumregions) {
1331                 mlog_errno(ret);
1332                 goto bail;
1333         }
1334
1335         o2hb_debug_failedregions =
1336                         o2hb_debug_create(O2HB_DEBUG_FAILEDREGIONS,
1337                                           o2hb_debug_dir,
1338                                           &o2hb_db_failedregions,
1339                                           sizeof(*o2hb_db_failedregions),
1340                                           O2HB_DB_TYPE_FAILEDREGIONS,
1341                                           sizeof(o2hb_failed_region_bitmap),
1342                                           O2NM_MAX_REGIONS,
1343                                           o2hb_failed_region_bitmap);
1344         if (!o2hb_debug_failedregions) {
1345                 mlog_errno(ret);
1346                 goto bail;
1347         }
1348
1349         ret = 0;
1350 bail:
1351         if (ret)
1352                 o2hb_exit();
1353
1354         return ret;
1355 }
1356
1357 int o2hb_init(void)
1358 {
1359         int i;
1360
1361         for (i = 0; i < ARRAY_SIZE(o2hb_callbacks); i++)
1362                 INIT_LIST_HEAD(&o2hb_callbacks[i].list);
1363
1364         for (i = 0; i < ARRAY_SIZE(o2hb_live_slots); i++)
1365                 INIT_LIST_HEAD(&o2hb_live_slots[i]);
1366
1367         INIT_LIST_HEAD(&o2hb_node_events);
1368
1369         memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
1370         memset(o2hb_region_bitmap, 0, sizeof(o2hb_region_bitmap));
1371         memset(o2hb_live_region_bitmap, 0, sizeof(o2hb_live_region_bitmap));
1372         memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
1373         memset(o2hb_failed_region_bitmap, 0, sizeof(o2hb_failed_region_bitmap));
1374
1375         o2hb_dependent_users = 0;
1376
1377         return o2hb_debug_init();
1378 }
1379
1380 /* if we're already in a callback then we're already serialized by the sem */
1381 static void o2hb_fill_node_map_from_callback(unsigned long *map,
1382                                              unsigned bytes)
1383 {
1384         BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1385
1386         memcpy(map, &o2hb_live_node_bitmap, bytes);
1387 }
1388
1389 /*
1390  * get a map of all nodes that are heartbeating in any regions
1391  */
1392 void o2hb_fill_node_map(unsigned long *map, unsigned bytes)
1393 {
1394         /* callers want to serialize this map and callbacks so that they
1395          * can trust that they don't miss nodes coming to the party */
1396         down_read(&o2hb_callback_sem);
1397         spin_lock(&o2hb_live_lock);
1398         o2hb_fill_node_map_from_callback(map, bytes);
1399         spin_unlock(&o2hb_live_lock);
1400         up_read(&o2hb_callback_sem);
1401 }
1402 EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
1403
1404 /*
1405  * heartbeat configfs bits.  The heartbeat set is a default set under
1406  * the cluster set in nodemanager.c.
1407  */
1408
1409 static struct o2hb_region *to_o2hb_region(struct config_item *item)
1410 {
1411         return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
1412 }
1413
1414 /* drop_item only drops its ref after killing the thread, nothing should
1415  * be using the region anymore.  this has to clean up any state that
1416  * attributes might have built up. */
1417 static void o2hb_region_release(struct config_item *item)
1418 {
1419         int i;
1420         struct page *page;
1421         struct o2hb_region *reg = to_o2hb_region(item);
1422
1423         mlog(ML_HEARTBEAT, "hb region release (%s)\n", reg->hr_dev_name);
1424
1425         kfree(reg->hr_tmp_block);
1426
1427         if (reg->hr_slot_data) {
1428                 for (i = 0; i < reg->hr_num_pages; i++) {
1429                         page = reg->hr_slot_data[i];
1430                         if (page)
1431                                 __free_page(page);
1432                 }
1433                 kfree(reg->hr_slot_data);
1434         }
1435
1436         if (reg->hr_bdev)
1437                 blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1438
1439         kfree(reg->hr_slots);
1440
1441         kfree(reg->hr_db_regnum);
1442         kfree(reg->hr_db_livenodes);
1443         debugfs_remove(reg->hr_debug_livenodes);
1444         debugfs_remove(reg->hr_debug_regnum);
1445         debugfs_remove(reg->hr_debug_elapsed_time);
1446         debugfs_remove(reg->hr_debug_pinned);
1447         debugfs_remove(reg->hr_debug_dir);
1448
1449         spin_lock(&o2hb_live_lock);
1450         list_del(&reg->hr_all_item);
1451         spin_unlock(&o2hb_live_lock);
1452
1453         kfree(reg);
1454 }
1455
1456 static int o2hb_read_block_input(struct o2hb_region *reg,
1457                                  const char *page,
1458                                  size_t count,
1459                                  unsigned long *ret_bytes,
1460                                  unsigned int *ret_bits)
1461 {
1462         unsigned long bytes;
1463         char *p = (char *)page;
1464
1465         bytes = simple_strtoul(p, &p, 0);
1466         if (!p || (*p && (*p != '\n')))
1467                 return -EINVAL;
1468
1469         /* Heartbeat and fs min / max block sizes are the same. */
1470         if (bytes > 4096 || bytes < 512)
1471                 return -ERANGE;
1472         if (hweight16(bytes) != 1)
1473                 return -EINVAL;
1474
1475         if (ret_bytes)
1476                 *ret_bytes = bytes;
1477         if (ret_bits)
1478                 *ret_bits = ffs(bytes) - 1;
1479
1480         return 0;
1481 }
1482
1483 static ssize_t o2hb_region_block_bytes_show(struct config_item *item,
1484                                             char *page)
1485 {
1486         return sprintf(page, "%u\n", to_o2hb_region(item)->hr_block_bytes);
1487 }
1488
1489 static ssize_t o2hb_region_block_bytes_store(struct config_item *item,
1490                                              const char *page,
1491                                              size_t count)
1492 {
1493         struct o2hb_region *reg = to_o2hb_region(item);
1494         int status;
1495         unsigned long block_bytes;
1496         unsigned int block_bits;
1497
1498         if (reg->hr_bdev)
1499                 return -EINVAL;
1500
1501         status = o2hb_read_block_input(reg, page, count,
1502                                        &block_bytes, &block_bits);
1503         if (status)
1504                 return status;
1505
1506         reg->hr_block_bytes = (unsigned int)block_bytes;
1507         reg->hr_block_bits = block_bits;
1508
1509         return count;
1510 }
1511
1512 static ssize_t o2hb_region_start_block_show(struct config_item *item,
1513                                             char *page)
1514 {
1515         return sprintf(page, "%llu\n", to_o2hb_region(item)->hr_start_block);
1516 }
1517
1518 static ssize_t o2hb_region_start_block_store(struct config_item *item,
1519                                              const char *page,
1520                                              size_t count)
1521 {
1522         struct o2hb_region *reg = to_o2hb_region(item);
1523         unsigned long long tmp;
1524         char *p = (char *)page;
1525
1526         if (reg->hr_bdev)
1527                 return -EINVAL;
1528
1529         tmp = simple_strtoull(p, &p, 0);
1530         if (!p || (*p && (*p != '\n')))
1531                 return -EINVAL;
1532
1533         reg->hr_start_block = tmp;
1534
1535         return count;
1536 }
1537
1538 static ssize_t o2hb_region_blocks_show(struct config_item *item, char *page)
1539 {
1540         return sprintf(page, "%d\n", to_o2hb_region(item)->hr_blocks);
1541 }
1542
1543 static ssize_t o2hb_region_blocks_store(struct config_item *item,
1544                                         const char *page,
1545                                         size_t count)
1546 {
1547         struct o2hb_region *reg = to_o2hb_region(item);
1548         unsigned long tmp;
1549         char *p = (char *)page;
1550
1551         if (reg->hr_bdev)
1552                 return -EINVAL;
1553
1554         tmp = simple_strtoul(p, &p, 0);
1555         if (!p || (*p && (*p != '\n')))
1556                 return -EINVAL;
1557
1558         if (tmp > O2NM_MAX_NODES || tmp == 0)
1559                 return -ERANGE;
1560
1561         reg->hr_blocks = (unsigned int)tmp;
1562
1563         return count;
1564 }
1565
1566 static ssize_t o2hb_region_dev_show(struct config_item *item, char *page)
1567 {
1568         unsigned int ret = 0;
1569
1570         if (to_o2hb_region(item)->hr_bdev)
1571                 ret = sprintf(page, "%s\n", to_o2hb_region(item)->hr_dev_name);
1572
1573         return ret;
1574 }
1575
1576 static void o2hb_init_region_params(struct o2hb_region *reg)
1577 {
1578         reg->hr_slots_per_page = PAGE_CACHE_SIZE >> reg->hr_block_bits;
1579         reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
1580
1581         mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
1582              reg->hr_start_block, reg->hr_blocks);
1583         mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
1584              reg->hr_block_bytes, reg->hr_block_bits);
1585         mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
1586         mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
1587 }
1588
1589 static int o2hb_map_slot_data(struct o2hb_region *reg)
1590 {
1591         int i, j;
1592         unsigned int last_slot;
1593         unsigned int spp = reg->hr_slots_per_page;
1594         struct page *page;
1595         char *raw;
1596         struct o2hb_disk_slot *slot;
1597
1598         reg->hr_tmp_block = kmalloc(reg->hr_block_bytes, GFP_KERNEL);
1599         if (reg->hr_tmp_block == NULL)
1600                 return -ENOMEM;
1601
1602         reg->hr_slots = kcalloc(reg->hr_blocks,
1603                                 sizeof(struct o2hb_disk_slot), GFP_KERNEL);
1604         if (reg->hr_slots == NULL)
1605                 return -ENOMEM;
1606
1607         for(i = 0; i < reg->hr_blocks; i++) {
1608                 slot = &reg->hr_slots[i];
1609                 slot->ds_node_num = i;
1610                 INIT_LIST_HEAD(&slot->ds_live_item);
1611                 slot->ds_raw_block = NULL;
1612         }
1613
1614         reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
1615         mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
1616                            "at %u blocks per page\n",
1617              reg->hr_num_pages, reg->hr_blocks, spp);
1618
1619         reg->hr_slot_data = kcalloc(reg->hr_num_pages, sizeof(struct page *),
1620                                     GFP_KERNEL);
1621         if (!reg->hr_slot_data)
1622                 return -ENOMEM;
1623
1624         for(i = 0; i < reg->hr_num_pages; i++) {
1625                 page = alloc_page(GFP_KERNEL);
1626                 if (!page)
1627                         return -ENOMEM;
1628
1629                 reg->hr_slot_data[i] = page;
1630
1631                 last_slot = i * spp;
1632                 raw = page_address(page);
1633                 for (j = 0;
1634                      (j < spp) && ((j + last_slot) < reg->hr_blocks);
1635                      j++) {
1636                         BUG_ON((j + last_slot) >= reg->hr_blocks);
1637
1638                         slot = &reg->hr_slots[j + last_slot];
1639                         slot->ds_raw_block =
1640                                 (struct o2hb_disk_heartbeat_block *) raw;
1641
1642                         raw += reg->hr_block_bytes;
1643                 }
1644         }
1645
1646         return 0;
1647 }
1648
1649 /* Read in all the slots available and populate the tracking
1650  * structures so that we can start with a baseline idea of what's
1651  * there. */
1652 static int o2hb_populate_slot_data(struct o2hb_region *reg)
1653 {
1654         int ret, i;
1655         struct o2hb_disk_slot *slot;
1656         struct o2hb_disk_heartbeat_block *hb_block;
1657
1658         ret = o2hb_read_slots(reg, reg->hr_blocks);
1659         if (ret)
1660                 goto out;
1661
1662         /* We only want to get an idea of the values initially in each
1663          * slot, so we do no verification - o2hb_check_slot will
1664          * actually determine if each configured slot is valid and
1665          * whether any values have changed. */
1666         for(i = 0; i < reg->hr_blocks; i++) {
1667                 slot = &reg->hr_slots[i];
1668                 hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
1669
1670                 /* Only fill the values that o2hb_check_slot uses to
1671                  * determine changing slots */
1672                 slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
1673                 slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
1674         }
1675
1676 out:
1677         return ret;
1678 }
1679
1680 /* this is acting as commit; we set up all of hr_bdev and hr_task or nothing */
1681 static ssize_t o2hb_region_dev_store(struct config_item *item,
1682                                      const char *page,
1683                                      size_t count)
1684 {
1685         struct o2hb_region *reg = to_o2hb_region(item);
1686         struct task_struct *hb_task;
1687         long fd;
1688         int sectsize;
1689         char *p = (char *)page;
1690         struct fd f;
1691         struct inode *inode;
1692         ssize_t ret = -EINVAL;
1693         int live_threshold;
1694
1695         if (reg->hr_bdev)
1696                 goto out;
1697
1698         /* We can't heartbeat without having had our node number
1699          * configured yet. */
1700         if (o2nm_this_node() == O2NM_MAX_NODES)
1701                 goto out;
1702
1703         fd = simple_strtol(p, &p, 0);
1704         if (!p || (*p && (*p != '\n')))
1705                 goto out;
1706
1707         if (fd < 0 || fd >= INT_MAX)
1708                 goto out;
1709
1710         f = fdget(fd);
1711         if (f.file == NULL)
1712                 goto out;
1713
1714         if (reg->hr_blocks == 0 || reg->hr_start_block == 0 ||
1715             reg->hr_block_bytes == 0)
1716                 goto out2;
1717
1718         inode = igrab(f.file->f_mapping->host);
1719         if (inode == NULL)
1720                 goto out2;
1721
1722         if (!S_ISBLK(inode->i_mode))
1723                 goto out3;
1724
1725         reg->hr_bdev = I_BDEV(f.file->f_mapping->host);
1726         ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ, NULL);
1727         if (ret) {
1728                 reg->hr_bdev = NULL;
1729                 goto out3;
1730         }
1731         inode = NULL;
1732
1733         bdevname(reg->hr_bdev, reg->hr_dev_name);
1734
1735         sectsize = bdev_logical_block_size(reg->hr_bdev);
1736         if (sectsize != reg->hr_block_bytes) {
1737                 mlog(ML_ERROR,
1738                      "blocksize %u incorrect for device, expected %d",
1739                      reg->hr_block_bytes, sectsize);
1740                 ret = -EINVAL;
1741                 goto out3;
1742         }
1743
1744         o2hb_init_region_params(reg);
1745
1746         /* Generation of zero is invalid */
1747         do {
1748                 get_random_bytes(&reg->hr_generation,
1749                                  sizeof(reg->hr_generation));
1750         } while (reg->hr_generation == 0);
1751
1752         ret = o2hb_map_slot_data(reg);
1753         if (ret) {
1754                 mlog_errno(ret);
1755                 goto out3;
1756         }
1757
1758         ret = o2hb_populate_slot_data(reg);
1759         if (ret) {
1760                 mlog_errno(ret);
1761                 goto out3;
1762         }
1763
1764         INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
1765
1766         /*
1767          * A node is considered live after it has beat LIVE_THRESHOLD
1768          * times.  We're not steady until we've given them a chance
1769          * _after_ our first read.
1770          * The default threshold is bare minimum so as to limit the delay
1771          * during mounts. For global heartbeat, the threshold doubled for the
1772          * first region.
1773          */
1774         live_threshold = O2HB_LIVE_THRESHOLD;
1775         if (o2hb_global_heartbeat_active()) {
1776                 spin_lock(&o2hb_live_lock);
1777                 if (bitmap_weight(o2hb_region_bitmap, O2NM_MAX_REGIONS) == 1)
1778                         live_threshold <<= 1;
1779                 spin_unlock(&o2hb_live_lock);
1780         }
1781         ++live_threshold;
1782         atomic_set(&reg->hr_steady_iterations, live_threshold);
1783         /* unsteady_iterations is double the steady_iterations */
1784         atomic_set(&reg->hr_unsteady_iterations, (live_threshold << 1));
1785
1786         hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
1787                               reg->hr_item.ci_name);
1788         if (IS_ERR(hb_task)) {
1789                 ret = PTR_ERR(hb_task);
1790                 mlog_errno(ret);
1791                 goto out3;
1792         }
1793
1794         spin_lock(&o2hb_live_lock);
1795         reg->hr_task = hb_task;
1796         spin_unlock(&o2hb_live_lock);
1797
1798         ret = wait_event_interruptible(o2hb_steady_queue,
1799                                 atomic_read(&reg->hr_steady_iterations) == 0 ||
1800                                 reg->hr_node_deleted);
1801         if (ret) {
1802                 atomic_set(&reg->hr_steady_iterations, 0);
1803                 reg->hr_aborted_start = 1;
1804         }
1805
1806         if (reg->hr_aborted_start) {
1807                 ret = -EIO;
1808                 goto out3;
1809         }
1810
1811         if (reg->hr_node_deleted) {
1812                 ret = -EINVAL;
1813                 goto out3;
1814         }
1815
1816         /* Ok, we were woken.  Make sure it wasn't by drop_item() */
1817         spin_lock(&o2hb_live_lock);
1818         hb_task = reg->hr_task;
1819         if (o2hb_global_heartbeat_active())
1820                 set_bit(reg->hr_region_num, o2hb_live_region_bitmap);
1821         spin_unlock(&o2hb_live_lock);
1822
1823         if (hb_task)
1824                 ret = count;
1825         else
1826                 ret = -EIO;
1827
1828         if (hb_task && o2hb_global_heartbeat_active())
1829                 printk(KERN_NOTICE "o2hb: Heartbeat started on region %s (%s)\n",
1830                        config_item_name(&reg->hr_item), reg->hr_dev_name);
1831
1832 out3:
1833         iput(inode);
1834 out2:
1835         fdput(f);
1836 out:
1837         if (ret < 0) {
1838                 if (reg->hr_bdev) {
1839                         blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1840                         reg->hr_bdev = NULL;
1841                 }
1842         }
1843         return ret;
1844 }
1845
1846 static ssize_t o2hb_region_pid_show(struct config_item *item, char *page)
1847 {
1848         struct o2hb_region *reg = to_o2hb_region(item);
1849         pid_t pid = 0;
1850
1851         spin_lock(&o2hb_live_lock);
1852         if (reg->hr_task)
1853                 pid = task_pid_nr(reg->hr_task);
1854         spin_unlock(&o2hb_live_lock);
1855
1856         if (!pid)
1857                 return 0;
1858
1859         return sprintf(page, "%u\n", pid);
1860 }
1861
1862 CONFIGFS_ATTR(o2hb_region_, block_bytes);
1863 CONFIGFS_ATTR(o2hb_region_, start_block);
1864 CONFIGFS_ATTR(o2hb_region_, blocks);
1865 CONFIGFS_ATTR(o2hb_region_, dev);
1866 CONFIGFS_ATTR_RO(o2hb_region_, pid);
1867
1868 static struct configfs_attribute *o2hb_region_attrs[] = {
1869         &o2hb_region_attr_block_bytes,
1870         &o2hb_region_attr_start_block,
1871         &o2hb_region_attr_blocks,
1872         &o2hb_region_attr_dev,
1873         &o2hb_region_attr_pid,
1874         NULL,
1875 };
1876
1877 static struct configfs_item_operations o2hb_region_item_ops = {
1878         .release                = o2hb_region_release,
1879 };
1880
1881 static struct config_item_type o2hb_region_type = {
1882         .ct_item_ops    = &o2hb_region_item_ops,
1883         .ct_attrs       = o2hb_region_attrs,
1884         .ct_owner       = THIS_MODULE,
1885 };
1886
1887 /* heartbeat set */
1888
1889 struct o2hb_heartbeat_group {
1890         struct config_group hs_group;
1891         /* some stuff? */
1892 };
1893
1894 static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
1895 {
1896         return group ?
1897                 container_of(group, struct o2hb_heartbeat_group, hs_group)
1898                 : NULL;
1899 }
1900
1901 static int o2hb_debug_region_init(struct o2hb_region *reg, struct dentry *dir)
1902 {
1903         int ret = -ENOMEM;
1904
1905         reg->hr_debug_dir =
1906                 debugfs_create_dir(config_item_name(&reg->hr_item), dir);
1907         if (!reg->hr_debug_dir) {
1908                 mlog_errno(ret);
1909                 goto bail;
1910         }
1911
1912         reg->hr_debug_livenodes =
1913                         o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1914                                           reg->hr_debug_dir,
1915                                           &(reg->hr_db_livenodes),
1916                                           sizeof(*(reg->hr_db_livenodes)),
1917                                           O2HB_DB_TYPE_REGION_LIVENODES,
1918                                           sizeof(reg->hr_live_node_bitmap),
1919                                           O2NM_MAX_NODES, reg);
1920         if (!reg->hr_debug_livenodes) {
1921                 mlog_errno(ret);
1922                 goto bail;
1923         }
1924
1925         reg->hr_debug_regnum =
1926                         o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER,
1927                                           reg->hr_debug_dir,
1928                                           &(reg->hr_db_regnum),
1929                                           sizeof(*(reg->hr_db_regnum)),
1930                                           O2HB_DB_TYPE_REGION_NUMBER,
1931                                           0, O2NM_MAX_NODES, reg);
1932         if (!reg->hr_debug_regnum) {
1933                 mlog_errno(ret);
1934                 goto bail;
1935         }
1936
1937         reg->hr_debug_elapsed_time =
1938                         o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME,
1939                                           reg->hr_debug_dir,
1940                                           &(reg->hr_db_elapsed_time),
1941                                           sizeof(*(reg->hr_db_elapsed_time)),
1942                                           O2HB_DB_TYPE_REGION_ELAPSED_TIME,
1943                                           0, 0, reg);
1944         if (!reg->hr_debug_elapsed_time) {
1945                 mlog_errno(ret);
1946                 goto bail;
1947         }
1948
1949         reg->hr_debug_pinned =
1950                         o2hb_debug_create(O2HB_DEBUG_REGION_PINNED,
1951                                           reg->hr_debug_dir,
1952                                           &(reg->hr_db_pinned),
1953                                           sizeof(*(reg->hr_db_pinned)),
1954                                           O2HB_DB_TYPE_REGION_PINNED,
1955                                           0, 0, reg);
1956         if (!reg->hr_debug_pinned) {
1957                 mlog_errno(ret);
1958                 goto bail;
1959         }
1960
1961         ret = 0;
1962 bail:
1963         return ret;
1964 }
1965
1966 static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
1967                                                           const char *name)
1968 {
1969         struct o2hb_region *reg = NULL;
1970         int ret;
1971
1972         reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
1973         if (reg == NULL)
1974                 return ERR_PTR(-ENOMEM);
1975
1976         if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
1977                 ret = -ENAMETOOLONG;
1978                 goto free;
1979         }
1980
1981         spin_lock(&o2hb_live_lock);
1982         reg->hr_region_num = 0;
1983         if (o2hb_global_heartbeat_active()) {
1984                 reg->hr_region_num = find_first_zero_bit(o2hb_region_bitmap,
1985                                                          O2NM_MAX_REGIONS);
1986                 if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
1987                         spin_unlock(&o2hb_live_lock);
1988                         ret = -EFBIG;
1989                         goto free;
1990                 }
1991                 set_bit(reg->hr_region_num, o2hb_region_bitmap);
1992         }
1993         list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
1994         spin_unlock(&o2hb_live_lock);
1995
1996         config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
1997
1998         ret = o2hb_debug_region_init(reg, o2hb_debug_dir);
1999         if (ret) {
2000                 config_item_put(&reg->hr_item);
2001                 goto free;
2002         }
2003
2004         return &reg->hr_item;
2005 free:
2006         kfree(reg);
2007         return ERR_PTR(ret);
2008 }
2009
2010 static void o2hb_heartbeat_group_drop_item(struct config_group *group,
2011                                            struct config_item *item)
2012 {
2013         struct task_struct *hb_task;
2014         struct o2hb_region *reg = to_o2hb_region(item);
2015         int quorum_region = 0;
2016
2017         /* stop the thread when the user removes the region dir */
2018         spin_lock(&o2hb_live_lock);
2019         hb_task = reg->hr_task;
2020         reg->hr_task = NULL;
2021         reg->hr_item_dropped = 1;
2022         spin_unlock(&o2hb_live_lock);
2023
2024         if (hb_task)
2025                 kthread_stop(hb_task);
2026
2027         if (o2hb_global_heartbeat_active()) {
2028                 spin_lock(&o2hb_live_lock);
2029                 clear_bit(reg->hr_region_num, o2hb_region_bitmap);
2030                 clear_bit(reg->hr_region_num, o2hb_live_region_bitmap);
2031                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
2032                         quorum_region = 1;
2033                 clear_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
2034                 spin_unlock(&o2hb_live_lock);
2035                 printk(KERN_NOTICE "o2hb: Heartbeat %s on region %s (%s)\n",
2036                        ((atomic_read(&reg->hr_steady_iterations) == 0) ?
2037                         "stopped" : "start aborted"), config_item_name(item),
2038                        reg->hr_dev_name);
2039         }
2040
2041         /*
2042          * If we're racing a dev_write(), we need to wake them.  They will
2043          * check reg->hr_task
2044          */
2045         if (atomic_read(&reg->hr_steady_iterations) != 0) {
2046                 reg->hr_aborted_start = 1;
2047                 atomic_set(&reg->hr_steady_iterations, 0);
2048                 wake_up(&o2hb_steady_queue);
2049         }
2050
2051         config_item_put(item);
2052
2053         if (!o2hb_global_heartbeat_active() || !quorum_region)
2054                 return;
2055
2056         /*
2057          * If global heartbeat active and there are dependent users,
2058          * pin all regions if quorum region count <= CUT_OFF
2059          */
2060         spin_lock(&o2hb_live_lock);
2061
2062         if (!o2hb_dependent_users)
2063                 goto unlock;
2064
2065         if (bitmap_weight(o2hb_quorum_region_bitmap,
2066                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2067                 o2hb_region_pin(NULL);
2068
2069 unlock:
2070         spin_unlock(&o2hb_live_lock);
2071 }
2072
2073 static ssize_t o2hb_heartbeat_group_threshold_show(struct config_item *item,
2074                 char *page)
2075 {
2076         return sprintf(page, "%u\n", o2hb_dead_threshold);
2077 }
2078
2079 static ssize_t o2hb_heartbeat_group_threshold_store(struct config_item *item,
2080                 const char *page, size_t count)
2081 {
2082         unsigned long tmp;
2083         char *p = (char *)page;
2084
2085         tmp = simple_strtoul(p, &p, 10);
2086         if (!p || (*p && (*p != '\n')))
2087                 return -EINVAL;
2088
2089         /* this will validate ranges for us. */
2090         o2hb_dead_threshold_set((unsigned int) tmp);
2091
2092         return count;
2093 }
2094
2095 static ssize_t o2hb_heartbeat_group_mode_show(struct config_item *item,
2096                 char *page)
2097 {
2098         return sprintf(page, "%s\n",
2099                        o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
2100 }
2101
2102 static ssize_t o2hb_heartbeat_group_mode_store(struct config_item *item,
2103                 const char *page, size_t count)
2104 {
2105         unsigned int i;
2106         int ret;
2107         size_t len;
2108
2109         len = (page[count - 1] == '\n') ? count - 1 : count;
2110         if (!len)
2111                 return -EINVAL;
2112
2113         for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
2114                 if (strncasecmp(page, o2hb_heartbeat_mode_desc[i], len))
2115                         continue;
2116
2117                 ret = o2hb_global_heartbeat_mode_set(i);
2118                 if (!ret)
2119                         printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
2120                                o2hb_heartbeat_mode_desc[i]);
2121                 return count;
2122         }
2123
2124         return -EINVAL;
2125
2126 }
2127
2128 CONFIGFS_ATTR(o2hb_heartbeat_group_, threshold);
2129 CONFIGFS_ATTR(o2hb_heartbeat_group_, mode);
2130
2131 static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
2132         &o2hb_heartbeat_group_attr_threshold,
2133         &o2hb_heartbeat_group_attr_mode,
2134         NULL,
2135 };
2136
2137 static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
2138         .make_item      = o2hb_heartbeat_group_make_item,
2139         .drop_item      = o2hb_heartbeat_group_drop_item,
2140 };
2141
2142 static struct config_item_type o2hb_heartbeat_group_type = {
2143         .ct_group_ops   = &o2hb_heartbeat_group_group_ops,
2144         .ct_attrs       = o2hb_heartbeat_group_attrs,
2145         .ct_owner       = THIS_MODULE,
2146 };
2147
2148 /* this is just here to avoid touching group in heartbeat.h which the
2149  * entire damn world #includes */
2150 struct config_group *o2hb_alloc_hb_set(void)
2151 {
2152         struct o2hb_heartbeat_group *hs = NULL;
2153         struct config_group *ret = NULL;
2154
2155         hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
2156         if (hs == NULL)
2157                 goto out;
2158
2159         config_group_init_type_name(&hs->hs_group, "heartbeat",
2160                                     &o2hb_heartbeat_group_type);
2161
2162         ret = &hs->hs_group;
2163 out:
2164         if (ret == NULL)
2165                 kfree(hs);
2166         return ret;
2167 }
2168
2169 void o2hb_free_hb_set(struct config_group *group)
2170 {
2171         struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
2172         kfree(hs);
2173 }
2174
2175 /* hb callback registration and issuing */
2176
2177 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
2178 {
2179         if (type == O2HB_NUM_CB)
2180                 return ERR_PTR(-EINVAL);
2181
2182         return &o2hb_callbacks[type];
2183 }
2184
2185 void o2hb_setup_callback(struct o2hb_callback_func *hc,
2186                          enum o2hb_callback_type type,
2187                          o2hb_cb_func *func,
2188                          void *data,
2189                          int priority)
2190 {
2191         INIT_LIST_HEAD(&hc->hc_item);
2192         hc->hc_func = func;
2193         hc->hc_data = data;
2194         hc->hc_priority = priority;
2195         hc->hc_type = type;
2196         hc->hc_magic = O2HB_CB_MAGIC;
2197 }
2198 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
2199
2200 /*
2201  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2202  * In global heartbeat mode, region_uuid passed is NULL.
2203  *
2204  * In local, we only pin the matching region. In global we pin all the active
2205  * regions.
2206  */
2207 static int o2hb_region_pin(const char *region_uuid)
2208 {
2209         int ret = 0, found = 0;
2210         struct o2hb_region *reg;
2211         char *uuid;
2212
2213         assert_spin_locked(&o2hb_live_lock);
2214
2215         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2216                 if (reg->hr_item_dropped)
2217                         continue;
2218
2219                 uuid = config_item_name(&reg->hr_item);
2220
2221                 /* local heartbeat */
2222                 if (region_uuid) {
2223                         if (strcmp(region_uuid, uuid))
2224                                 continue;
2225                         found = 1;
2226                 }
2227
2228                 if (reg->hr_item_pinned || reg->hr_item_dropped)
2229                         goto skip_pin;
2230
2231                 /* Ignore ENOENT only for local hb (userdlm domain) */
2232                 ret = o2nm_depend_item(&reg->hr_item);
2233                 if (!ret) {
2234                         mlog(ML_CLUSTER, "Pin region %s\n", uuid);
2235                         reg->hr_item_pinned = 1;
2236                 } else {
2237                         if (ret == -ENOENT && found)
2238                                 ret = 0;
2239                         else {
2240                                 mlog(ML_ERROR, "Pin region %s fails with %d\n",
2241                                      uuid, ret);
2242                                 break;
2243                         }
2244                 }
2245 skip_pin:
2246                 if (found)
2247                         break;
2248         }
2249
2250         return ret;
2251 }
2252
2253 /*
2254  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2255  * In global heartbeat mode, region_uuid passed is NULL.
2256  *
2257  * In local, we only unpin the matching region. In global we unpin all the
2258  * active regions.
2259  */
2260 static void o2hb_region_unpin(const char *region_uuid)
2261 {
2262         struct o2hb_region *reg;
2263         char *uuid;
2264         int found = 0;
2265
2266         assert_spin_locked(&o2hb_live_lock);
2267
2268         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2269                 if (reg->hr_item_dropped)
2270                         continue;
2271
2272                 uuid = config_item_name(&reg->hr_item);
2273                 if (region_uuid) {
2274                         if (strcmp(region_uuid, uuid))
2275                                 continue;
2276                         found = 1;
2277                 }
2278
2279                 if (reg->hr_item_pinned) {
2280                         mlog(ML_CLUSTER, "Unpin region %s\n", uuid);
2281                         o2nm_undepend_item(&reg->hr_item);
2282                         reg->hr_item_pinned = 0;
2283                 }
2284                 if (found)
2285                         break;
2286         }
2287 }
2288
2289 static int o2hb_region_inc_user(const char *region_uuid)
2290 {
2291         int ret = 0;
2292
2293         spin_lock(&o2hb_live_lock);
2294
2295         /* local heartbeat */
2296         if (!o2hb_global_heartbeat_active()) {
2297             ret = o2hb_region_pin(region_uuid);
2298             goto unlock;
2299         }
2300
2301         /*
2302          * if global heartbeat active and this is the first dependent user,
2303          * pin all regions if quorum region count <= CUT_OFF
2304          */
2305         o2hb_dependent_users++;
2306         if (o2hb_dependent_users > 1)
2307                 goto unlock;
2308
2309         if (bitmap_weight(o2hb_quorum_region_bitmap,
2310                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2311                 ret = o2hb_region_pin(NULL);
2312
2313 unlock:
2314         spin_unlock(&o2hb_live_lock);
2315         return ret;
2316 }
2317
2318 void o2hb_region_dec_user(const char *region_uuid)
2319 {
2320         spin_lock(&o2hb_live_lock);
2321
2322         /* local heartbeat */
2323         if (!o2hb_global_heartbeat_active()) {
2324             o2hb_region_unpin(region_uuid);
2325             goto unlock;
2326         }
2327
2328         /*
2329          * if global heartbeat active and there are no dependent users,
2330          * unpin all quorum regions
2331          */
2332         o2hb_dependent_users--;
2333         if (!o2hb_dependent_users)
2334                 o2hb_region_unpin(NULL);
2335
2336 unlock:
2337         spin_unlock(&o2hb_live_lock);
2338 }
2339
2340 int o2hb_register_callback(const char *region_uuid,
2341                            struct o2hb_callback_func *hc)
2342 {
2343         struct o2hb_callback_func *f;
2344         struct o2hb_callback *hbcall;
2345         int ret;
2346
2347         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2348         BUG_ON(!list_empty(&hc->hc_item));
2349
2350         hbcall = hbcall_from_type(hc->hc_type);
2351         if (IS_ERR(hbcall)) {
2352                 ret = PTR_ERR(hbcall);
2353                 goto out;
2354         }
2355
2356         if (region_uuid) {
2357                 ret = o2hb_region_inc_user(region_uuid);
2358                 if (ret) {
2359                         mlog_errno(ret);
2360                         goto out;
2361                 }
2362         }
2363
2364         down_write(&o2hb_callback_sem);
2365
2366         list_for_each_entry(f, &hbcall->list, hc_item) {
2367                 if (hc->hc_priority < f->hc_priority) {
2368                         list_add_tail(&hc->hc_item, &f->hc_item);
2369                         break;
2370                 }
2371         }
2372         if (list_empty(&hc->hc_item))
2373                 list_add_tail(&hc->hc_item, &hbcall->list);
2374
2375         up_write(&o2hb_callback_sem);
2376         ret = 0;
2377 out:
2378         mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
2379              ret, __builtin_return_address(0), hc);
2380         return ret;
2381 }
2382 EXPORT_SYMBOL_GPL(o2hb_register_callback);
2383
2384 void o2hb_unregister_callback(const char *region_uuid,
2385                               struct o2hb_callback_func *hc)
2386 {
2387         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2388
2389         mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
2390              __builtin_return_address(0), hc);
2391
2392         /* XXX Can this happen _with_ a region reference? */
2393         if (list_empty(&hc->hc_item))
2394                 return;
2395
2396         if (region_uuid)
2397                 o2hb_region_dec_user(region_uuid);
2398
2399         down_write(&o2hb_callback_sem);
2400
2401         list_del_init(&hc->hc_item);
2402
2403         up_write(&o2hb_callback_sem);
2404 }
2405 EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
2406
2407 int o2hb_check_node_heartbeating(u8 node_num)
2408 {
2409         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2410
2411         o2hb_fill_node_map(testing_map, sizeof(testing_map));
2412         if (!test_bit(node_num, testing_map)) {
2413                 mlog(ML_HEARTBEAT,
2414                      "node (%u) does not have heartbeating enabled.\n",
2415                      node_num);
2416                 return 0;
2417         }
2418
2419         return 1;
2420 }
2421 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating);
2422
2423 int o2hb_check_node_heartbeating_no_sem(u8 node_num)
2424 {
2425         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2426         unsigned long flags;
2427
2428         spin_lock_irqsave(&o2hb_live_lock, flags);
2429         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2430         spin_unlock_irqrestore(&o2hb_live_lock, flags);
2431         if (!test_bit(node_num, testing_map)) {
2432                 mlog(ML_HEARTBEAT,
2433                      "node (%u) does not have heartbeating enabled.\n",
2434                      node_num);
2435                 return 0;
2436         }
2437
2438         return 1;
2439 }
2440 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_no_sem);
2441
2442 int o2hb_check_node_heartbeating_from_callback(u8 node_num)
2443 {
2444         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2445
2446         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2447         if (!test_bit(node_num, testing_map)) {
2448                 mlog(ML_HEARTBEAT,
2449                      "node (%u) does not have heartbeating enabled.\n",
2450                      node_num);
2451                 return 0;
2452         }
2453
2454         return 1;
2455 }
2456 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_from_callback);
2457
2458 /* Makes sure our local node is configured with a node number, and is
2459  * heartbeating. */
2460 int o2hb_check_local_node_heartbeating(void)
2461 {
2462         u8 node_num;
2463
2464         /* if this node was set then we have networking */
2465         node_num = o2nm_this_node();
2466         if (node_num == O2NM_MAX_NODES) {
2467                 mlog(ML_HEARTBEAT, "this node has not been configured.\n");
2468                 return 0;
2469         }
2470
2471         return o2hb_check_node_heartbeating(node_num);
2472 }
2473 EXPORT_SYMBOL_GPL(o2hb_check_local_node_heartbeating);
2474
2475 /*
2476  * this is just a hack until we get the plumbing which flips file systems
2477  * read only and drops the hb ref instead of killing the node dead.
2478  */
2479 void o2hb_stop_all_regions(void)
2480 {
2481         struct o2hb_region *reg;
2482
2483         mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");
2484
2485         spin_lock(&o2hb_live_lock);
2486
2487         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
2488                 reg->hr_unclean_stop = 1;
2489
2490         spin_unlock(&o2hb_live_lock);
2491 }
2492 EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
2493
2494 int o2hb_get_all_regions(char *region_uuids, u8 max_regions)
2495 {
2496         struct o2hb_region *reg;
2497         int numregs = 0;
2498         char *p;
2499
2500         spin_lock(&o2hb_live_lock);
2501
2502         p = region_uuids;
2503         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2504                 if (reg->hr_item_dropped)
2505                         continue;
2506
2507                 mlog(0, "Region: %s\n", config_item_name(&reg->hr_item));
2508                 if (numregs < max_regions) {
2509                         memcpy(p, config_item_name(&reg->hr_item),
2510                                O2HB_MAX_REGION_NAME_LEN);
2511                         p += O2HB_MAX_REGION_NAME_LEN;
2512                 }
2513                 numregs++;
2514         }
2515
2516         spin_unlock(&o2hb_live_lock);
2517
2518         return numregs;
2519 }
2520 EXPORT_SYMBOL_GPL(o2hb_get_all_regions);
2521
2522 int o2hb_global_heartbeat_active(void)
2523 {
2524         return (o2hb_heartbeat_mode == O2HB_HEARTBEAT_GLOBAL);
2525 }
2526 EXPORT_SYMBOL(o2hb_global_heartbeat_active);