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         struct o2hb_region *reg =
 291                 container_of(work, struct o2hb_region,
 292                              hr_write_timeout_work.work);
 293
 294         mlog(ML_ERROR, "Heartbeat write timeout to device %s after %u "
 295              "milliseconds\n", reg->hr_dev_name,
 296              jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
 297
 298         if (o2hb_global_heartbeat_active()) {
 299                 spin_lock(&o2hb_live_lock);
 300                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 301                         set_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 302                 failed = bitmap_weight(o2hb_failed_region_bitmap,
 303                                         O2NM_MAX_REGIONS);
 304                 quorum = bitmap_weight(o2hb_quorum_region_bitmap,
 305                                         O2NM_MAX_REGIONS);
 306                 spin_unlock(&o2hb_live_lock);
 307
 308                 mlog(ML_HEARTBEAT, "Number of regions %d, failed regions %d\n",
 309                      quorum, failed);
 310
 311                 /*
 312                  * Fence if the number of failed regions >= half the number
 313                  * of  quorum regions
 314                  */
 315                 if ((failed << 1) < quorum)
 316                         return;
 317         }
 318
 319         o2quo_disk_timeout();
 320 }
 321
 322 static void o2hb_arm_write_timeout(struct o2hb_region *reg)
 323 {
 324         /* Arm writeout only after thread reaches steady state */
 325         if (atomic_read(&reg->hr_steady_iterations) != 0)
 326                 return;
 327
 328         mlog(ML_HEARTBEAT, "Queue write timeout for %u ms\n",
 329              O2HB_MAX_WRITE_TIMEOUT_MS);
 330
 331         if (o2hb_global_heartbeat_active()) {
 332                 spin_lock(&o2hb_live_lock);
 333                 clear_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 334                 spin_unlock(&o2hb_live_lock);
 335         }
 336         cancel_delayed_work(&reg->hr_write_timeout_work);
 337         reg->hr_last_timeout_start = jiffies;
 338         schedule_delayed_work(&reg->hr_write_timeout_work,
 339                               msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
 340 }
 341
 342 static void o2hb_disarm_write_timeout(struct o2hb_region *reg)
 343 {
 344         cancel_delayed_work_sync(&reg->hr_write_timeout_work);
 345 }
 346
 347 static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
 348 {
 349         atomic_set(&wc->wc_num_reqs, 1);
 350         init_completion(&wc->wc_io_complete);
 351         wc->wc_error = 0;
 352 }
 353
 354 /* Used in error paths too */
 355 static inline void o2hb_bio_wait_dec(struct o2hb_bio_wait_ctxt *wc,
 356                                      unsigned int num)
 357 {
 358         /* sadly atomic_sub_and_test() isn't available on all platforms.  The
 359          * good news is that the fast path only completes one at a time */
 360         while(num--) {
 361                 if (atomic_dec_and_test(&wc->wc_num_reqs)) {
 362                         BUG_ON(num > 0);
 363                         complete(&wc->wc_io_complete);
 364                 }
 365         }
 366 }
 367
 368 static void o2hb_wait_on_io(struct o2hb_region *reg,
 369                             struct o2hb_bio_wait_ctxt *wc)
 370 {
 371         o2hb_bio_wait_dec(wc, 1);
 372         wait_for_completion(&wc->wc_io_complete);
 373 }
 374
 375 static void o2hb_bio_end_io(struct bio *bio)
 376 {
 377         struct o2hb_bio_wait_ctxt *wc = bio->bi_private;
 378
 379         if (bio->bi_error) {
 380                 mlog(ML_ERROR, "IO Error %d\n", bio->bi_error);
 381                 wc->wc_error = bio->bi_error;
 382         }
 383
 384         o2hb_bio_wait_dec(wc, 1);
 385         bio_put(bio);
 386 }
 387
 388 /* Setup a Bio to cover I/O against num_slots slots starting at
 389  * start_slot. */
 390 static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
 391                                       struct o2hb_bio_wait_ctxt *wc,
 392                                       unsigned int *current_slot,
 393                                       unsigned int max_slots)
 394 {
 395         int len, current_page;
 396         unsigned int vec_len, vec_start;
 397         unsigned int bits = reg->hr_block_bits;
 398         unsigned int spp = reg->hr_slots_per_page;
 399         unsigned int cs = *current_slot;
 400         struct bio *bio;
 401         struct page *page;
 402
 403         /* Testing has shown this allocation to take long enough under
 404          * GFP_KERNEL that the local node can get fenced. It would be
 405          * nicest if we could pre-allocate these bios and avoid this
 406          * all together. */
 407         bio = bio_alloc(GFP_ATOMIC, 16);
 408         if (!bio) {
 409                 mlog(ML_ERROR, "Could not alloc slots BIO!\n");
 410                 bio = ERR_PTR(-ENOMEM);
 411                 goto bail;
 412         }
 413
 414         /* Must put everything in 512 byte sectors for the bio... */
 415         bio->bi_iter.bi_sector = (reg->hr_start_block + cs) << (bits - 9);
 416         bio->bi_bdev = reg->hr_bdev;
 417         bio->bi_private = wc;
 418         bio->bi_end_io = o2hb_bio_end_io;
 419
 420         vec_start = (cs << bits) % PAGE_SIZE;
 421         while(cs < max_slots) {
 422                 current_page = cs / spp;
 423                 page = reg->hr_slot_data[current_page];
 424
 425                 vec_len = min(PAGE_SIZE - vec_start,
 426                               (max_slots-cs) * (PAGE_SIZE/spp) );
 427
 428                 mlog(ML_HB_BIO, "page %d, vec_len = %u, vec_start = %u\n",
 429                      current_page, vec_len, vec_start);
 430
 431                 len = bio_add_page(bio, page, vec_len, vec_start);
 432                 if (len != vec_len) break;
 433
 434                 cs += vec_len / (PAGE_SIZE/spp);
 435                 vec_start = 0;
 436         }
 437
 438 bail:
 439         *current_slot = cs;
 440         return bio;
 441 }
 442
 443 static int o2hb_read_slots(struct o2hb_region *reg,
 444                            unsigned int max_slots)
 445 {
 446         unsigned int current_slot=0;
 447         int status;
 448         struct o2hb_bio_wait_ctxt wc;
 449         struct bio *bio;
 450
 451         o2hb_bio_wait_init(&wc);
 452
 453         while(current_slot < max_slots) {
 454                 bio = o2hb_setup_one_bio(reg, &wc, &current_slot, max_slots);
 455                 if (IS_ERR(bio)) {
 456                         status = PTR_ERR(bio);
 457                         mlog_errno(status);
 458                         goto bail_and_wait;
 459                 }
 460
 461                 atomic_inc(&wc.wc_num_reqs);
 462                 submit_bio(READ, bio);
 463         }
 464
 465         status = 0;
 466
 467 bail_and_wait:
 468         o2hb_wait_on_io(reg, &wc);
 469         if (wc.wc_error && !status)
 470                 status = wc.wc_error;
 471
 472         return status;
 473 }
 474
 475 static int o2hb_issue_node_write(struct o2hb_region *reg,
 476                                  struct o2hb_bio_wait_ctxt *write_wc)
 477 {
 478         int status;
 479         unsigned int slot;
 480         struct bio *bio;
 481
 482         o2hb_bio_wait_init(write_wc);
 483
 484         slot = o2nm_this_node();
 485
 486         bio = o2hb_setup_one_bio(reg, write_wc, &slot, slot+1);
 487         if (IS_ERR(bio)) {
 488                 status = PTR_ERR(bio);
 489                 mlog_errno(status);
 490                 goto bail;
 491         }
 492
 493         atomic_inc(&write_wc->wc_num_reqs);
 494         submit_bio(WRITE_SYNC, bio);
 495
 496         status = 0;
 497 bail:
 498         return status;
 499 }
 500
 501 static u32 o2hb_compute_block_crc_le(struct o2hb_region *reg,
 502                                      struct o2hb_disk_heartbeat_block *hb_block)
 503 {
 504         __le32 old_cksum;
 505         u32 ret;
 506
 507         /* We want to compute the block crc with a 0 value in the
 508          * hb_cksum field. Save it off here and replace after the
 509          * crc. */
 510         old_cksum = hb_block->hb_cksum;
 511         hb_block->hb_cksum = 0;
 512
 513         ret = crc32_le(0, (unsigned char *) hb_block, reg->hr_block_bytes);
 514
 515         hb_block->hb_cksum = old_cksum;
 516
 517         return ret;
 518 }
 519
 520 static void o2hb_dump_slot(struct o2hb_disk_heartbeat_block *hb_block)
 521 {
 522         mlog(ML_ERROR, "Dump slot information: seq = 0x%llx, node = %u, "
 523              "cksum = 0x%x, generation 0x%llx\n",
 524              (long long)le64_to_cpu(hb_block->hb_seq),
 525              hb_block->hb_node, le32_to_cpu(hb_block->hb_cksum),
 526              (long long)le64_to_cpu(hb_block->hb_generation));
 527 }
 528
 529 static int o2hb_verify_crc(struct o2hb_region *reg,
 530                            struct o2hb_disk_heartbeat_block *hb_block)
 531 {
 532         u32 read, computed;
 533
 534         read = le32_to_cpu(hb_block->hb_cksum);
 535         computed = o2hb_compute_block_crc_le(reg, hb_block);
 536
 537         return read == computed;
 538 }
 539
 540 /*
 541  * Compare the slot data with what we wrote in the last iteration.
 542  * If the match fails, print an appropriate error message. This is to
 543  * detect errors like... another node hearting on the same slot,
 544  * flaky device that is losing writes, etc.
 545  * Returns 1 if check succeeds, 0 otherwise.
 546  */
 547 static int o2hb_check_own_slot(struct o2hb_region *reg)
 548 {
 549         struct o2hb_disk_slot *slot;
 550         struct o2hb_disk_heartbeat_block *hb_block;
 551         char *errstr;
 552
 553         slot = &reg->hr_slots[o2nm_this_node()];
 554         /* Don't check on our 1st timestamp */
 555         if (!slot->ds_last_time)
 556                 return 0;
 557
 558         hb_block = slot->ds_raw_block;
 559         if (le64_to_cpu(hb_block->hb_seq) == slot->ds_last_time &&
 560             le64_to_cpu(hb_block->hb_generation) == slot->ds_last_generation &&
 561             hb_block->hb_node == slot->ds_node_num)
 562                 return 1;
 563
 564 #define ERRSTR1         "Another node is heartbeating on device"
 565 #define ERRSTR2         "Heartbeat generation mismatch on device"
 566 #define ERRSTR3         "Heartbeat sequence mismatch on device"
 567
 568         if (hb_block->hb_node != slot->ds_node_num)
 569                 errstr = ERRSTR1;
 570         else if (le64_to_cpu(hb_block->hb_generation) !=
 571                  slot->ds_last_generation)
 572                 errstr = ERRSTR2;
 573         else
 574                 errstr = ERRSTR3;
 575
 576         mlog(ML_ERROR, "%s (%s): expected(%u:0x%llx, 0x%llx), "
 577              "ondisk(%u:0x%llx, 0x%llx)\n", errstr, reg->hr_dev_name,
 578              slot->ds_node_num, (unsigned long long)slot->ds_last_generation,
 579              (unsigned long long)slot->ds_last_time, hb_block->hb_node,
 580              (unsigned long long)le64_to_cpu(hb_block->hb_generation),
 581              (unsigned long long)le64_to_cpu(hb_block->hb_seq));
 582
 583         return 0;
 584 }
 585
 586 static inline void o2hb_prepare_block(struct o2hb_region *reg,
 587                                       u64 generation)
 588 {
 589         int node_num;
 590         u64 cputime;
 591         struct o2hb_disk_slot *slot;
 592         struct o2hb_disk_heartbeat_block *hb_block;
 593
 594         node_num = o2nm_this_node();
 595         slot = &reg->hr_slots[node_num];
 596
 597         hb_block = (struct o2hb_disk_heartbeat_block *)slot->ds_raw_block;
 598         memset(hb_block, 0, reg->hr_block_bytes);
 599         /* TODO: time stuff */
 600         cputime = CURRENT_TIME.tv_sec;
 601         if (!cputime)
 602                 cputime = 1;
 603
 604         hb_block->hb_seq = cpu_to_le64(cputime);
 605         hb_block->hb_node = node_num;
 606         hb_block->hb_generation = cpu_to_le64(generation);
 607         hb_block->hb_dead_ms = cpu_to_le32(o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS);
 608
 609         /* This step must always happen last! */
 610         hb_block->hb_cksum = cpu_to_le32(o2hb_compute_block_crc_le(reg,
 611                                                                    hb_block));
 612
 613         mlog(ML_HB_BIO, "our node generation = 0x%llx, cksum = 0x%x\n",
 614              (long long)generation,
 615              le32_to_cpu(hb_block->hb_cksum));
 616 }
 617
 618 static void o2hb_fire_callbacks(struct o2hb_callback *hbcall,
 619                                 struct o2nm_node *node,
 620                                 int idx)
 621 {
 622         struct o2hb_callback_func *f;
 623
 624         list_for_each_entry(f, &hbcall->list, hc_item) {
 625                 mlog(ML_HEARTBEAT, "calling funcs %p\n", f);
 626                 (f->hc_func)(node, idx, f->hc_data);
 627         }
 628 }
 629
 630 /* Will run the list in order until we process the passed event */
 631 static void o2hb_run_event_list(struct o2hb_node_event *queued_event)
 632 {
 633         struct o2hb_callback *hbcall;
 634         struct o2hb_node_event *event;
 635
 636         /* Holding callback sem assures we don't alter the callback
 637          * lists when doing this, and serializes ourselves with other
 638          * processes wanting callbacks. */
 639         down_write(&o2hb_callback_sem);
 640
 641         spin_lock(&o2hb_live_lock);
 642         while (!list_empty(&o2hb_node_events)
 643                && !list_empty(&queued_event->hn_item)) {
 644                 event = list_entry(o2hb_node_events.next,
 645                                    struct o2hb_node_event,
 646                                    hn_item);
 647                 list_del_init(&event->hn_item);
 648                 spin_unlock(&o2hb_live_lock);
 649
 650                 mlog(ML_HEARTBEAT, "Node %s event for %d\n",
 651                      event->hn_event_type == O2HB_NODE_UP_CB ? "UP" : "DOWN",
 652                      event->hn_node_num);
 653
 654                 hbcall = hbcall_from_type(event->hn_event_type);
 655
 656                 /* We should *never* have gotten on to the list with a
 657                  * bad type... This isn't something that we should try
 658                  * to recover from. */
 659                 BUG_ON(IS_ERR(hbcall));
 660
 661                 o2hb_fire_callbacks(hbcall, event->hn_node, event->hn_node_num);
 662
 663                 spin_lock(&o2hb_live_lock);
 664         }
 665         spin_unlock(&o2hb_live_lock);
 666
 667         up_write(&o2hb_callback_sem);
 668 }
 669
 670 static void o2hb_queue_node_event(struct o2hb_node_event *event,
 671                                   enum o2hb_callback_type type,
 672                                   struct o2nm_node *node,
 673                                   int node_num)
 674 {
 675         assert_spin_locked(&o2hb_live_lock);
 676
 677         BUG_ON((!node) && (type != O2HB_NODE_DOWN_CB));
 678
 679         event->hn_event_type = type;
 680         event->hn_node = node;
 681         event->hn_node_num = node_num;
 682
 683         mlog(ML_HEARTBEAT, "Queue node %s event for node %d\n",
 684              type == O2HB_NODE_UP_CB ? "UP" : "DOWN", node_num);
 685
 686         list_add_tail(&event->hn_item, &o2hb_node_events);
 687 }
 688
 689 static void o2hb_shutdown_slot(struct o2hb_disk_slot *slot)
 690 {
 691         struct o2hb_node_event event =
 692                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 693         struct o2nm_node *node;
 694         int queued = 0;
 695
 696         node = o2nm_get_node_by_num(slot->ds_node_num);
 697         if (!node)
 698                 return;
 699
 700         spin_lock(&o2hb_live_lock);
 701         if (!list_empty(&slot->ds_live_item)) {
 702                 mlog(ML_HEARTBEAT, "Shutdown, node %d leaves region\n",
 703                      slot->ds_node_num);
 704
 705                 list_del_init(&slot->ds_live_item);
 706
 707                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 708                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 709
 710                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB, node,
 711                                               slot->ds_node_num);
 712                         queued = 1;
 713                 }
 714         }
 715         spin_unlock(&o2hb_live_lock);
 716
 717         if (queued)
 718                 o2hb_run_event_list(&event);
 719
 720         o2nm_node_put(node);
 721 }
 722
 723 static void o2hb_set_quorum_device(struct o2hb_region *reg)
 724 {
 725         if (!o2hb_global_heartbeat_active())
 726                 return;
 727
 728         /* Prevent race with o2hb_heartbeat_group_drop_item() */
 729         if (kthread_should_stop())
 730                 return;
 731
 732         /* Tag region as quorum only after thread reaches steady state */
 733         if (atomic_read(&reg->hr_steady_iterations) != 0)
 734                 return;
 735
 736         spin_lock(&o2hb_live_lock);
 737
 738         if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 739                 goto unlock;
 740
 741         /*
 742          * A region can be added to the quorum only when it sees all
 743          * live nodes heartbeat on it. In other words, the region has been
 744          * added to all nodes.
 745          */
 746         if (memcmp(reg->hr_live_node_bitmap, o2hb_live_node_bitmap,
 747                    sizeof(o2hb_live_node_bitmap)))
 748                 goto unlock;
 749
 750         printk(KERN_NOTICE "o2hb: Region %s (%s) is now a quorum device\n",
 751                config_item_name(&reg->hr_item), reg->hr_dev_name);
 752
 753         set_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
 754
 755         /*
 756          * If global heartbeat active, unpin all regions if the
 757          * region count > CUT_OFF
 758          */
 759         if (bitmap_weight(o2hb_quorum_region_bitmap,
 760                            O2NM_MAX_REGIONS) > O2HB_PIN_CUT_OFF)
 761                 o2hb_region_unpin(NULL);
 762 unlock:
 763         spin_unlock(&o2hb_live_lock);
 764 }
 765
 766 static int o2hb_check_slot(struct o2hb_region *reg,
 767                            struct o2hb_disk_slot *slot)
 768 {
 769         int changed = 0, gen_changed = 0;
 770         struct o2hb_node_event event =
 771                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 772         struct o2nm_node *node;
 773         struct o2hb_disk_heartbeat_block *hb_block = reg->hr_tmp_block;
 774         u64 cputime;
 775         unsigned int dead_ms = o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS;
 776         unsigned int slot_dead_ms;
 777         int tmp;
 778         int queued = 0;
 779
 780         memcpy(hb_block, slot->ds_raw_block, reg->hr_block_bytes);
 781
 782         /*
 783          * If a node is no longer configured but is still in the livemap, we
 784          * may need to clear that bit from the livemap.
 785          */
 786         node = o2nm_get_node_by_num(slot->ds_node_num);
 787         if (!node) {
 788                 spin_lock(&o2hb_live_lock);
 789                 tmp = test_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 790                 spin_unlock(&o2hb_live_lock);
 791                 if (!tmp)
 792                         return 0;
 793         }
 794
 795         if (!o2hb_verify_crc(reg, hb_block)) {
 796                 /* all paths from here will drop o2hb_live_lock for
 797                  * us. */
 798                 spin_lock(&o2hb_live_lock);
 799
 800                 /* Don't print an error on the console in this case -
 801                  * a freshly formatted heartbeat area will not have a
 802                  * crc set on it. */
 803                 if (list_empty(&slot->ds_live_item))
 804                         goto out;
 805
 806                 /* The node is live but pushed out a bad crc. We
 807                  * consider it a transient miss but don't populate any
 808                  * other values as they may be junk. */
 809                 mlog(ML_ERROR, "Node %d has written a bad crc to %s\n",
 810                      slot->ds_node_num, reg->hr_dev_name);
 811                 o2hb_dump_slot(hb_block);
 812
 813                 slot->ds_equal_samples++;
 814                 goto fire_callbacks;
 815         }
 816
 817         /* we don't care if these wrap.. the state transitions below
 818          * clear at the right places */
 819         cputime = le64_to_cpu(hb_block->hb_seq);
 820         if (slot->ds_last_time != cputime)
 821                 slot->ds_changed_samples++;
 822         else
 823                 slot->ds_equal_samples++;
 824         slot->ds_last_time = cputime;
 825
 826         /* The node changed heartbeat generations. We assume this to
 827          * mean it dropped off but came back before we timed out. We
 828          * want to consider it down for the time being but don't want
 829          * to lose any changed_samples state we might build up to
 830          * considering it live again. */
 831         if (slot->ds_last_generation != le64_to_cpu(hb_block->hb_generation)) {
 832                 gen_changed = 1;
 833                 slot->ds_equal_samples = 0;
 834                 mlog(ML_HEARTBEAT, "Node %d changed generation (0x%llx "
 835                      "to 0x%llx)\n", slot->ds_node_num,
 836                      (long long)slot->ds_last_generation,
 837                      (long long)le64_to_cpu(hb_block->hb_generation));
 838         }
 839
 840         slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
 841
 842         mlog(ML_HEARTBEAT, "Slot %d gen 0x%llx cksum 0x%x "
 843              "seq %llu last %llu changed %u equal %u\n",
 844              slot->ds_node_num, (long long)slot->ds_last_generation,
 845              le32_to_cpu(hb_block->hb_cksum),
 846              (unsigned long long)le64_to_cpu(hb_block->hb_seq),
 847              (unsigned long long)slot->ds_last_time, slot->ds_changed_samples,
 848              slot->ds_equal_samples);
 849
 850         spin_lock(&o2hb_live_lock);
 851
 852 fire_callbacks:
 853         /* dead nodes only come to life after some number of
 854          * changes at any time during their dead time */
 855         if (list_empty(&slot->ds_live_item) &&
 856             slot->ds_changed_samples >= O2HB_LIVE_THRESHOLD) {
 857                 mlog(ML_HEARTBEAT, "Node %d (id 0x%llx) joined my region\n",
 858                      slot->ds_node_num, (long long)slot->ds_last_generation);
 859
 860                 set_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 861
 862                 /* first on the list generates a callback */
 863                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 864                         mlog(ML_HEARTBEAT, "o2hb: Add node %d to live nodes "
 865                              "bitmap\n", slot->ds_node_num);
 866                         set_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 867
 868                         o2hb_queue_node_event(&event, O2HB_NODE_UP_CB, node,
 869                                               slot->ds_node_num);
 870
 871                         changed = 1;
 872                         queued = 1;
 873                 }
 874
 875                 list_add_tail(&slot->ds_live_item,
 876                               &o2hb_live_slots[slot->ds_node_num]);
 877
 878                 slot->ds_equal_samples = 0;
 879
 880                 /* We want to be sure that all nodes agree on the
 881                  * number of milliseconds before a node will be
 882                  * considered dead. The self-fencing timeout is
 883                  * computed from this value, and a discrepancy might
 884                  * result in heartbeat calling a node dead when it
 885                  * hasn't self-fenced yet. */
 886                 slot_dead_ms = le32_to_cpu(hb_block->hb_dead_ms);
 887                 if (slot_dead_ms && slot_dead_ms != dead_ms) {
 888                         /* TODO: Perhaps we can fail the region here. */
 889                         mlog(ML_ERROR, "Node %d on device %s has a dead count "
 890                              "of %u ms, but our count is %u ms.\n"
 891                              "Please double check your configuration values "
 892                              "for 'O2CB_HEARTBEAT_THRESHOLD'\n",
 893                              slot->ds_node_num, reg->hr_dev_name, slot_dead_ms,
 894                              dead_ms);
 895                 }
 896                 goto out;
 897         }
 898
 899         /* if the list is dead, we're done.. */
 900         if (list_empty(&slot->ds_live_item))
 901                 goto out;
 902
 903         /* live nodes only go dead after enough consequtive missed
 904          * samples..  reset the missed counter whenever we see
 905          * activity */
 906         if (slot->ds_equal_samples >= o2hb_dead_threshold || gen_changed) {
 907                 mlog(ML_HEARTBEAT, "Node %d left my region\n",
 908                      slot->ds_node_num);
 909
 910                 clear_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 911
 912                 /* last off the live_slot generates a callback */
 913                 list_del_init(&slot->ds_live_item);
 914                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 915                         mlog(ML_HEARTBEAT, "o2hb: Remove node %d from live "
 916                              "nodes bitmap\n", slot->ds_node_num);
 917                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 918
 919                         /* node can be null */
 920                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB,
 921                                               node, slot->ds_node_num);
 922
 923                         changed = 1;
 924                         queued = 1;
 925                 }
 926
 927                 /* We don't clear this because the node is still
 928                  * actually writing new blocks. */
 929                 if (!gen_changed)
 930                         slot->ds_changed_samples = 0;
 931                 goto out;
 932         }
 933         if (slot->ds_changed_samples) {
 934                 slot->ds_changed_samples = 0;
 935                 slot->ds_equal_samples = 0;
 936         }
 937 out:
 938         spin_unlock(&o2hb_live_lock);
 939
 940         if (queued)
 941                 o2hb_run_event_list(&event);
 942
 943         if (node)
 944                 o2nm_node_put(node);
 945         return changed;
 946 }
 947
 948 static int o2hb_highest_node(unsigned long *nodes, int numbits)
 949 {
 950         return find_last_bit(nodes, numbits);
 951 }
 952
 953 static int o2hb_do_disk_heartbeat(struct o2hb_region *reg)
 954 {
 955         int i, ret, highest_node;
 956         int membership_change = 0, own_slot_ok = 0;
 957         unsigned long configured_nodes[BITS_TO_LONGS(O2NM_MAX_NODES)];
 958         unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 959         struct o2hb_bio_wait_ctxt write_wc;
 960
 961         ret = o2nm_configured_node_map(configured_nodes,
 962                                        sizeof(configured_nodes));
 963         if (ret) {
 964                 mlog_errno(ret);
 965                 goto bail;
 966         }
 967
 968         /*
 969          * If a node is not configured but is in the livemap, we still need
 970          * to read the slot so as to be able to remove it from the livemap.
 971          */
 972         o2hb_fill_node_map(live_node_bitmap, sizeof(live_node_bitmap));
 973         i = -1;
 974         while ((i = find_next_bit(live_node_bitmap,
 975                                   O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
 976                 set_bit(i, configured_nodes);
 977         }
 978
 979         highest_node = o2hb_highest_node(configured_nodes, O2NM_MAX_NODES);
 980         if (highest_node >= O2NM_MAX_NODES) {
 981                 mlog(ML_NOTICE, "o2hb: No configured nodes found!\n");
 982                 ret = -EINVAL;
 983                 goto bail;
 984         }
 985
 986         /* No sense in reading the slots of nodes that don't exist
 987          * yet. Of course, if the node definitions have holes in them
 988          * then we're reading an empty slot anyway... Consider this
 989          * best-effort. */
 990         ret = o2hb_read_slots(reg, highest_node + 1);
 991         if (ret < 0) {
 992                 mlog_errno(ret);
 993                 goto bail;
 994         }
 995
 996         /* With an up to date view of the slots, we can check that no
 997          * other node has been improperly configured to heartbeat in
 998          * our slot. */
 999         own_slot_ok = o2hb_check_own_slot(reg);
1000
1001         /* fill in the proper info for our next heartbeat */
1002         o2hb_prepare_block(reg, reg->hr_generation);
1003
1004         ret = o2hb_issue_node_write(reg, &write_wc);
1005         if (ret < 0) {
1006                 mlog_errno(ret);
1007                 goto bail;
1008         }
1009
1010         i = -1;
1011         while((i = find_next_bit(configured_nodes,
1012                                  O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
1013                 membership_change |= o2hb_check_slot(reg, &reg->hr_slots[i]);
1014         }
1015
1016         /*
1017          * We have to be sure we've advertised ourselves on disk
1018          * before we can go to steady state.  This ensures that
1019          * people we find in our steady state have seen us.
1020          */
1021         o2hb_wait_on_io(reg, &write_wc);
1022         if (write_wc.wc_error) {
1023                 /* Do not re-arm the write timeout on I/O error - we
1024                  * can't be sure that the new block ever made it to
1025                  * disk */
1026                 mlog(ML_ERROR, "Write error %d on device \"%s\"\n",
1027                      write_wc.wc_error, reg->hr_dev_name);
1028                 ret = write_wc.wc_error;
1029                 goto bail;
1030         }
1031
1032         /* Skip disarming the timeout if own slot has stale/bad data */
1033         if (own_slot_ok) {
1034                 o2hb_set_quorum_device(reg);
1035                 o2hb_arm_write_timeout(reg);
1036         }
1037
1038 bail:
1039         /* let the person who launched us know when things are steady */
1040         if (atomic_read(&reg->hr_steady_iterations) != 0) {
1041                 if (!ret && own_slot_ok && !membership_change) {
1042                         if (atomic_dec_and_test(&reg->hr_steady_iterations))
1043                                 wake_up(&o2hb_steady_queue);
1044                 }
1045         }
1046
1047         if (atomic_read(&reg->hr_steady_iterations) != 0) {
1048                 if (atomic_dec_and_test(&reg->hr_unsteady_iterations)) {
1049                         printk(KERN_NOTICE "o2hb: Unable to stabilize "
1050                                "heartbeart on region %s (%s)\n",
1051                                config_item_name(&reg->hr_item),
1052                                reg->hr_dev_name);
1053                         atomic_set(&reg->hr_steady_iterations, 0);
1054                         reg->hr_aborted_start = 1;
1055                         wake_up(&o2hb_steady_queue);
1056                         ret = -EIO;
1057                 }
1058         }
1059
1060         return ret;
1061 }
1062
1063 /*
1064  * we ride the region ref that the region dir holds.  before the region
1065  * dir is removed and drops it ref it will wait to tear down this
1066  * thread.
1067  */
1068 static int o2hb_thread(void *data)
1069 {
1070         int i, ret;
1071         struct o2hb_region *reg = data;
1072         struct o2hb_bio_wait_ctxt write_wc;
1073         ktime_t before_hb, after_hb;
1074         unsigned int elapsed_msec;
1075
1076         mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n");
1077
1078         set_user_nice(current, MIN_NICE);
1079
1080         /* Pin node */
1081         ret = o2nm_depend_this_node();
1082         if (ret) {
1083                 mlog(ML_ERROR, "Node has been deleted, ret = %d\n", ret);
1084                 reg->hr_node_deleted = 1;
1085                 wake_up(&o2hb_steady_queue);
1086                 return 0;
1087         }
1088
1089         while (!kthread_should_stop() &&
1090                !reg->hr_unclean_stop && !reg->hr_aborted_start) {
1091                 /* We track the time spent inside
1092                  * o2hb_do_disk_heartbeat so that we avoid more than
1093                  * hr_timeout_ms between disk writes. On busy systems
1094                  * this should result in a heartbeat which is less
1095                  * likely to time itself out. */
1096                 before_hb = ktime_get_real();
1097
1098                 ret = o2hb_do_disk_heartbeat(reg);
1099
1100                 after_hb = ktime_get_real();
1101
1102                 elapsed_msec = (unsigned int)
1103                                 ktime_ms_delta(after_hb, before_hb);
1104
1105                 mlog(ML_HEARTBEAT,
1106                      "start = %lld, end = %lld, msec = %u, ret = %d\n",
1107                      before_hb.tv64, after_hb.tv64, elapsed_msec, ret);
1108
1109                 if (!kthread_should_stop() &&
1110                     elapsed_msec < reg->hr_timeout_ms) {
1111                         /* the kthread api has blocked signals for us so no
1112                          * need to record the return value. */
1113                         msleep_interruptible(reg->hr_timeout_ms - elapsed_msec);
1114                 }
1115         }
1116
1117         o2hb_disarm_write_timeout(reg);
1118
1119         /* unclean stop is only used in very bad situation */
1120         for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
1121                 o2hb_shutdown_slot(&reg->hr_slots[i]);
1122
1123         /* Explicit down notification - avoid forcing the other nodes
1124          * to timeout on this region when we could just as easily
1125          * write a clear generation - thus indicating to them that
1126          * this node has left this region.
1127          */
1128         if (!reg->hr_unclean_stop && !reg->hr_aborted_start) {
1129                 o2hb_prepare_block(reg, 0);
1130                 ret = o2hb_issue_node_write(reg, &write_wc);
1131                 if (ret == 0)
1132                         o2hb_wait_on_io(reg, &write_wc);
1133                 else
1134                         mlog_errno(ret);
1135         }
1136
1137         /* Unpin node */
1138         o2nm_undepend_this_node();
1139
1140         mlog(ML_HEARTBEAT|ML_KTHREAD, "o2hb thread exiting\n");
1141
1142         return 0;
1143 }
1144
1145 #ifdef CONFIG_DEBUG_FS
1146 static int o2hb_debug_open(struct inode *inode, struct file *file)
1147 {
1148         struct o2hb_debug_buf *db = inode->i_private;
1149         struct o2hb_region *reg;
1150         unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1151         unsigned long lts;
1152         char *buf = NULL;
1153         int i = -1;
1154         int out = 0;
1155
1156         /* max_nodes should be the largest bitmap we pass here */
1157         BUG_ON(sizeof(map) < db->db_size);
1158
1159         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1160         if (!buf)
1161                 goto bail;
1162
1163         switch (db->db_type) {
1164         case O2HB_DB_TYPE_LIVENODES:
1165         case O2HB_DB_TYPE_LIVEREGIONS:
1166         case O2HB_DB_TYPE_QUORUMREGIONS:
1167         case O2HB_DB_TYPE_FAILEDREGIONS:
1168                 spin_lock(&o2hb_live_lock);
1169                 memcpy(map, db->db_data, db->db_size);
1170                 spin_unlock(&o2hb_live_lock);
1171                 break;
1172
1173         case O2HB_DB_TYPE_REGION_LIVENODES:
1174                 spin_lock(&o2hb_live_lock);
1175                 reg = (struct o2hb_region *)db->db_data;
1176                 memcpy(map, reg->hr_live_node_bitmap, db->db_size);
1177                 spin_unlock(&o2hb_live_lock);
1178                 break;
1179
1180         case O2HB_DB_TYPE_REGION_NUMBER:
1181                 reg = (struct o2hb_region *)db->db_data;
1182                 out += snprintf(buf + out, PAGE_SIZE - out, "%d\n",
1183                                 reg->hr_region_num);
1184                 goto done;
1185
1186         case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
1187                 reg = (struct o2hb_region *)db->db_data;
1188                 lts = reg->hr_last_timeout_start;
1189                 /* If 0, it has never been set before */
1190                 if (lts)
1191                         lts = jiffies_to_msecs(jiffies - lts);
1192                 out += snprintf(buf + out, PAGE_SIZE - out, "%lu\n", lts);
1193                 goto done;
1194
1195         case O2HB_DB_TYPE_REGION_PINNED:
1196                 reg = (struct o2hb_region *)db->db_data;
1197                 out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
1198                                 !!reg->hr_item_pinned);
1199                 goto done;
1200
1201         default:
1202                 goto done;
1203         }
1204
1205         while ((i = find_next_bit(map, db->db_len, i + 1)) < db->db_len)
1206                 out += snprintf(buf + out, PAGE_SIZE - out, "%d ", i);
1207         out += snprintf(buf + out, PAGE_SIZE - out, "\n");
1208
1209 done:
1210         i_size_write(inode, out);
1211
1212         file->private_data = buf;
1213
1214         return 0;
1215 bail:
1216         return -ENOMEM;
1217 }
1218
1219 static int o2hb_debug_release(struct inode *inode, struct file *file)
1220 {
1221         kfree(file->private_data);
1222         return 0;
1223 }
1224
1225 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1226                                  size_t nbytes, loff_t *ppos)
1227 {
1228         return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
1229                                        i_size_read(file->f_mapping->host));
1230 }
1231 #else
1232 static int o2hb_debug_open(struct inode *inode, struct file *file)
1233 {
1234         return 0;
1235 }
1236 static int o2hb_debug_release(struct inode *inode, struct file *file)
1237 {
1238         return 0;
1239 }
1240 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1241                                size_t nbytes, loff_t *ppos)
1242 {
1243         return 0;
1244 }
1245 #endif  /* CONFIG_DEBUG_FS */
1246
1247 static const struct file_operations o2hb_debug_fops = {
1248         .open =         o2hb_debug_open,
1249         .release =      o2hb_debug_release,
1250         .read =         o2hb_debug_read,
1251         .llseek =       generic_file_llseek,
1252 };
1253
1254 void o2hb_exit(void)
1255 {
1256         debugfs_remove(o2hb_debug_failedregions);
1257         debugfs_remove(o2hb_debug_quorumregions);
1258         debugfs_remove(o2hb_debug_liveregions);
1259         debugfs_remove(o2hb_debug_livenodes);
1260         debugfs_remove(o2hb_debug_dir);
1261         kfree(o2hb_db_livenodes);
1262         kfree(o2hb_db_liveregions);
1263         kfree(o2hb_db_quorumregions);
1264         kfree(o2hb_db_failedregions);
1265 }
1266
1267 static struct dentry *o2hb_debug_create(const char *name, struct dentry *dir,
1268                                         struct o2hb_debug_buf **db, int db_len,
1269                                         int type, int size, int len, void *data)
1270 {
1271         *db = kmalloc(db_len, GFP_KERNEL);
1272         if (!*db)
1273                 return NULL;
1274
1275         (*db)->db_type = type;
1276         (*db)->db_size = size;
1277         (*db)->db_len = len;
1278         (*db)->db_data = data;
1279
1280         return debugfs_create_file(name, S_IFREG|S_IRUSR, dir, *db,
1281                                    &o2hb_debug_fops);
1282 }
1283
1284 static int o2hb_debug_init(void)
1285 {
1286         int ret = -ENOMEM;
1287
1288         o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
1289         if (!o2hb_debug_dir) {
1290                 mlog_errno(ret);
1291                 goto bail;
1292         }
1293
1294         o2hb_debug_livenodes = o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1295                                                  o2hb_debug_dir,
1296                                                  &o2hb_db_livenodes,
1297                                                  sizeof(*o2hb_db_livenodes),
1298                                                  O2HB_DB_TYPE_LIVENODES,
1299                                                  sizeof(o2hb_live_node_bitmap),
1300                                                  O2NM_MAX_NODES,
1301                                                  o2hb_live_node_bitmap);
1302         if (!o2hb_debug_livenodes) {
1303                 mlog_errno(ret);
1304                 goto bail;
1305         }
1306
1307         o2hb_debug_liveregions = o2hb_debug_create(O2HB_DEBUG_LIVEREGIONS,
1308                                                    o2hb_debug_dir,
1309                                                    &o2hb_db_liveregions,
1310                                                    sizeof(*o2hb_db_liveregions),
1311                                                    O2HB_DB_TYPE_LIVEREGIONS,
1312                                                    sizeof(o2hb_live_region_bitmap),
1313                                                    O2NM_MAX_REGIONS,
1314                                                    o2hb_live_region_bitmap);
1315         if (!o2hb_debug_liveregions) {
1316                 mlog_errno(ret);
1317                 goto bail;
1318         }
1319
1320         o2hb_debug_quorumregions =
1321                         o2hb_debug_create(O2HB_DEBUG_QUORUMREGIONS,
1322                                           o2hb_debug_dir,
1323                                           &o2hb_db_quorumregions,
1324                                           sizeof(*o2hb_db_quorumregions),
1325                                           O2HB_DB_TYPE_QUORUMREGIONS,
1326                                           sizeof(o2hb_quorum_region_bitmap),
1327                                           O2NM_MAX_REGIONS,
1328                                           o2hb_quorum_region_bitmap);
1329         if (!o2hb_debug_quorumregions) {
1330                 mlog_errno(ret);
1331                 goto bail;
1332         }
1333
1334         o2hb_debug_failedregions =
1335                         o2hb_debug_create(O2HB_DEBUG_FAILEDREGIONS,
1336                                           o2hb_debug_dir,
1337                                           &o2hb_db_failedregions,
1338                                           sizeof(*o2hb_db_failedregions),
1339                                           O2HB_DB_TYPE_FAILEDREGIONS,
1340                                           sizeof(o2hb_failed_region_bitmap),
1341                                           O2NM_MAX_REGIONS,
1342                                           o2hb_failed_region_bitmap);
1343         if (!o2hb_debug_failedregions) {
1344                 mlog_errno(ret);
1345                 goto bail;
1346         }
1347
1348         ret = 0;
1349 bail:
1350         if (ret)
1351                 o2hb_exit();
1352
1353         return ret;
1354 }
1355
1356 int o2hb_init(void)
1357 {
1358         int i;
1359
1360         for (i = 0; i < ARRAY_SIZE(o2hb_callbacks); i++)
1361                 INIT_LIST_HEAD(&o2hb_callbacks[i].list);
1362
1363         for (i = 0; i < ARRAY_SIZE(o2hb_live_slots); i++)
1364                 INIT_LIST_HEAD(&o2hb_live_slots[i]);
1365
1366         INIT_LIST_HEAD(&o2hb_node_events);
1367
1368         memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
1369         memset(o2hb_region_bitmap, 0, sizeof(o2hb_region_bitmap));
1370         memset(o2hb_live_region_bitmap, 0, sizeof(o2hb_live_region_bitmap));
1371         memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
1372         memset(o2hb_failed_region_bitmap, 0, sizeof(o2hb_failed_region_bitmap));
1373
1374         o2hb_dependent_users = 0;
1375
1376         return o2hb_debug_init();
1377 }
1378
1379 /* if we're already in a callback then we're already serialized by the sem */
1380 static void o2hb_fill_node_map_from_callback(unsigned long *map,
1381                                              unsigned bytes)
1382 {
1383         BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1384
1385         memcpy(map, &o2hb_live_node_bitmap, bytes);
1386 }
1387
1388 /*
1389  * get a map of all nodes that are heartbeating in any regions
1390  */
1391 void o2hb_fill_node_map(unsigned long *map, unsigned bytes)
1392 {
1393         /* callers want to serialize this map and callbacks so that they
1394          * can trust that they don't miss nodes coming to the party */
1395         down_read(&o2hb_callback_sem);
1396         spin_lock(&o2hb_live_lock);
1397         o2hb_fill_node_map_from_callback(map, bytes);
1398         spin_unlock(&o2hb_live_lock);
1399         up_read(&o2hb_callback_sem);
1400 }
1401 EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
1402
1403 /*
1404  * heartbeat configfs bits.  The heartbeat set is a default set under
1405  * the cluster set in nodemanager.c.
1406  */
1407
1408 static struct o2hb_region *to_o2hb_region(struct config_item *item)
1409 {
1410         return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
1411 }
1412
1413 /* drop_item only drops its ref after killing the thread, nothing should
1414  * be using the region anymore.  this has to clean up any state that
1415  * attributes might have built up. */
1416 static void o2hb_region_release(struct config_item *item)
1417 {
1418         int i;
1419         struct page *page;
1420         struct o2hb_region *reg = to_o2hb_region(item);
1421
1422         mlog(ML_HEARTBEAT, "hb region release (%s)\n", reg->hr_dev_name);
1423
1424         kfree(reg->hr_tmp_block);
1425
1426         if (reg->hr_slot_data) {
1427                 for (i = 0; i < reg->hr_num_pages; i++) {
1428                         page = reg->hr_slot_data[i];
1429                         if (page)
1430                                 __free_page(page);
1431                 }
1432                 kfree(reg->hr_slot_data);
1433         }
1434
1435         if (reg->hr_bdev)
1436                 blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1437
1438         kfree(reg->hr_slots);
1439
1440         debugfs_remove(reg->hr_debug_livenodes);
1441         debugfs_remove(reg->hr_debug_regnum);
1442         debugfs_remove(reg->hr_debug_elapsed_time);
1443         debugfs_remove(reg->hr_debug_pinned);
1444         debugfs_remove(reg->hr_debug_dir);
1445         kfree(reg->hr_db_livenodes);
1446         kfree(reg->hr_db_regnum);
1447         kfree(reg->hr_db_elapsed_time);
1448         kfree(reg->hr_db_pinned);
1449
1450         spin_lock(&o2hb_live_lock);
1451         list_del(&reg->hr_all_item);
1452         spin_unlock(&o2hb_live_lock);
1453
1454         kfree(reg);
1455 }
1456
1457 static int o2hb_read_block_input(struct o2hb_region *reg,
1458                                  const char *page,
1459                                  size_t count,
1460                                  unsigned long *ret_bytes,
1461                                  unsigned int *ret_bits)
1462 {
1463         unsigned long bytes;
1464         char *p = (char *)page;
1465
1466         bytes = simple_strtoul(p, &p, 0);
1467         if (!p || (*p && (*p != '\n')))
1468                 return -EINVAL;
1469
1470         /* Heartbeat and fs min / max block sizes are the same. */
1471         if (bytes > 4096 || bytes < 512)
1472                 return -ERANGE;
1473         if (hweight16(bytes) != 1)
1474                 return -EINVAL;
1475
1476         if (ret_bytes)
1477                 *ret_bytes = bytes;
1478         if (ret_bits)
1479                 *ret_bits = ffs(bytes) - 1;
1480
1481         return 0;
1482 }
1483
1484 static ssize_t o2hb_region_block_bytes_show(struct config_item *item,
1485                                             char *page)
1486 {
1487         return sprintf(page, "%u\n", to_o2hb_region(item)->hr_block_bytes);
1488 }
1489
1490 static ssize_t o2hb_region_block_bytes_store(struct config_item *item,
1491                                              const char *page,
1492                                              size_t count)
1493 {
1494         struct o2hb_region *reg = to_o2hb_region(item);
1495         int status;
1496         unsigned long block_bytes;
1497         unsigned int block_bits;
1498
1499         if (reg->hr_bdev)
1500                 return -EINVAL;
1501
1502         status = o2hb_read_block_input(reg, page, count,
1503                                        &block_bytes, &block_bits);
1504         if (status)
1505                 return status;
1506
1507         reg->hr_block_bytes = (unsigned int)block_bytes;
1508         reg->hr_block_bits = block_bits;
1509
1510         return count;
1511 }
1512
1513 static ssize_t o2hb_region_start_block_show(struct config_item *item,
1514                                             char *page)
1515 {
1516         return sprintf(page, "%llu\n", to_o2hb_region(item)->hr_start_block);
1517 }
1518
1519 static ssize_t o2hb_region_start_block_store(struct config_item *item,
1520                                              const char *page,
1521                                              size_t count)
1522 {
1523         struct o2hb_region *reg = to_o2hb_region(item);
1524         unsigned long long tmp;
1525         char *p = (char *)page;
1526
1527         if (reg->hr_bdev)
1528                 return -EINVAL;
1529
1530         tmp = simple_strtoull(p, &p, 0);
1531         if (!p || (*p && (*p != '\n')))
1532                 return -EINVAL;
1533
1534         reg->hr_start_block = tmp;
1535
1536         return count;
1537 }
1538
1539 static ssize_t o2hb_region_blocks_show(struct config_item *item, char *page)
1540 {
1541         return sprintf(page, "%d\n", to_o2hb_region(item)->hr_blocks);
1542 }
1543
1544 static ssize_t o2hb_region_blocks_store(struct config_item *item,
1545                                         const char *page,
1546                                         size_t count)
1547 {
1548         struct o2hb_region *reg = to_o2hb_region(item);
1549         unsigned long tmp;
1550         char *p = (char *)page;
1551
1552         if (reg->hr_bdev)
1553                 return -EINVAL;
1554
1555         tmp = simple_strtoul(p, &p, 0);
1556         if (!p || (*p && (*p != '\n')))
1557                 return -EINVAL;
1558
1559         if (tmp > O2NM_MAX_NODES || tmp == 0)
1560                 return -ERANGE;
1561
1562         reg->hr_blocks = (unsigned int)tmp;
1563
1564         return count;
1565 }
1566
1567 static ssize_t o2hb_region_dev_show(struct config_item *item, char *page)
1568 {
1569         unsigned int ret = 0;
1570
1571         if (to_o2hb_region(item)->hr_bdev)
1572                 ret = sprintf(page, "%s\n", to_o2hb_region(item)->hr_dev_name);
1573
1574         return ret;
1575 }
1576
1577 static void o2hb_init_region_params(struct o2hb_region *reg)
1578 {
1579         reg->hr_slots_per_page = PAGE_SIZE >> reg->hr_block_bits;
1580         reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
1581
1582         mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
1583              reg->hr_start_block, reg->hr_blocks);
1584         mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
1585              reg->hr_block_bytes, reg->hr_block_bits);
1586         mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
1587         mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
1588 }
1589
1590 static int o2hb_map_slot_data(struct o2hb_region *reg)
1591 {
1592         int i, j;
1593         unsigned int last_slot;
1594         unsigned int spp = reg->hr_slots_per_page;
1595         struct page *page;
1596         char *raw;
1597         struct o2hb_disk_slot *slot;
1598
1599         reg->hr_tmp_block = kmalloc(reg->hr_block_bytes, GFP_KERNEL);
1600         if (reg->hr_tmp_block == NULL)
1601                 return -ENOMEM;
1602
1603         reg->hr_slots = kcalloc(reg->hr_blocks,
1604                                 sizeof(struct o2hb_disk_slot), GFP_KERNEL);
1605         if (reg->hr_slots == NULL)
1606                 return -ENOMEM;
1607
1608         for(i = 0; i < reg->hr_blocks; i++) {
1609                 slot = &reg->hr_slots[i];
1610                 slot->ds_node_num = i;
1611                 INIT_LIST_HEAD(&slot->ds_live_item);
1612                 slot->ds_raw_block = NULL;
1613         }
1614
1615         reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
1616         mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
1617                            "at %u blocks per page\n",
1618              reg->hr_num_pages, reg->hr_blocks, spp);
1619
1620         reg->hr_slot_data = kcalloc(reg->hr_num_pages, sizeof(struct page *),
1621                                     GFP_KERNEL);
1622         if (!reg->hr_slot_data)
1623                 return -ENOMEM;
1624
1625         for(i = 0; i < reg->hr_num_pages; i++) {
1626                 page = alloc_page(GFP_KERNEL);
1627                 if (!page)
1628                         return -ENOMEM;
1629
1630                 reg->hr_slot_data[i] = page;
1631
1632                 last_slot = i * spp;
1633                 raw = page_address(page);
1634                 for (j = 0;
1635                      (j < spp) && ((j + last_slot) < reg->hr_blocks);
1636                      j++) {
1637                         BUG_ON((j + last_slot) >= reg->hr_blocks);
1638
1639                         slot = &reg->hr_slots[j + last_slot];
1640                         slot->ds_raw_block =
1641                                 (struct o2hb_disk_heartbeat_block *) raw;
1642
1643                         raw += reg->hr_block_bytes;
1644                 }
1645         }
1646
1647         return 0;
1648 }
1649
1650 /* Read in all the slots available and populate the tracking
1651  * structures so that we can start with a baseline idea of what's
1652  * there. */
1653 static int o2hb_populate_slot_data(struct o2hb_region *reg)
1654 {
1655         int ret, i;
1656         struct o2hb_disk_slot *slot;
1657         struct o2hb_disk_heartbeat_block *hb_block;
1658
1659         ret = o2hb_read_slots(reg, reg->hr_blocks);
1660         if (ret)
1661                 goto out;
1662
1663         /* We only want to get an idea of the values initially in each
1664          * slot, so we do no verification - o2hb_check_slot will
1665          * actually determine if each configured slot is valid and
1666          * whether any values have changed. */
1667         for(i = 0; i < reg->hr_blocks; i++) {
1668                 slot = &reg->hr_slots[i];
1669                 hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
1670
1671                 /* Only fill the values that o2hb_check_slot uses to
1672                  * determine changing slots */
1673                 slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
1674                 slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
1675         }
1676
1677 out:
1678         return ret;
1679 }
1680
1681 /* this is acting as commit; we set up all of hr_bdev and hr_task or nothing */
1682 static ssize_t o2hb_region_dev_store(struct config_item *item,
1683                                      const char *page,
1684                                      size_t count)
1685 {
1686         struct o2hb_region *reg = to_o2hb_region(item);
1687         struct task_struct *hb_task;
1688         long fd;
1689         int sectsize;
1690         char *p = (char *)page;
1691         struct fd f;
1692         struct inode *inode;
1693         ssize_t ret = -EINVAL;
1694         int live_threshold;
1695
1696         if (reg->hr_bdev)
1697                 goto out;
1698
1699         /* We can't heartbeat without having had our node number
1700          * configured yet. */
1701         if (o2nm_this_node() == O2NM_MAX_NODES)
1702                 goto out;
1703
1704         fd = simple_strtol(p, &p, 0);
1705         if (!p || (*p && (*p != '\n')))
1706                 goto out;
1707
1708         if (fd < 0 || fd >= INT_MAX)
1709                 goto out;
1710
1711         f = fdget(fd);
1712         if (f.file == NULL)
1713                 goto out;
1714
1715         if (reg->hr_blocks == 0 || reg->hr_start_block == 0 ||
1716             reg->hr_block_bytes == 0)
1717                 goto out2;
1718
1719         inode = igrab(f.file->f_mapping->host);
1720         if (inode == NULL)
1721                 goto out2;
1722
1723         if (!S_ISBLK(inode->i_mode))
1724                 goto out3;
1725
1726         reg->hr_bdev = I_BDEV(f.file->f_mapping->host);
1727         ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ, NULL);
1728         if (ret) {
1729                 reg->hr_bdev = NULL;
1730                 goto out3;
1731         }
1732         inode = NULL;
1733
1734         bdevname(reg->hr_bdev, reg->hr_dev_name);
1735
1736         sectsize = bdev_logical_block_size(reg->hr_bdev);
1737         if (sectsize != reg->hr_block_bytes) {
1738                 mlog(ML_ERROR,
1739                      "blocksize %u incorrect for device, expected %d",
1740                      reg->hr_block_bytes, sectsize);
1741                 ret = -EINVAL;
1742                 goto out3;
1743         }
1744
1745         o2hb_init_region_params(reg);
1746
1747         /* Generation of zero is invalid */
1748         do {
1749                 get_random_bytes(&reg->hr_generation,
1750                                  sizeof(reg->hr_generation));
1751         } while (reg->hr_generation == 0);
1752
1753         ret = o2hb_map_slot_data(reg);
1754         if (ret) {
1755                 mlog_errno(ret);
1756                 goto out3;
1757         }
1758
1759         ret = o2hb_populate_slot_data(reg);
1760         if (ret) {
1761                 mlog_errno(ret);
1762                 goto out3;
1763         }
1764
1765         INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
1766
1767         /*
1768          * A node is considered live after it has beat LIVE_THRESHOLD
1769          * times.  We're not steady until we've given them a chance
1770          * _after_ our first read.
1771          * The default threshold is bare minimum so as to limit the delay
1772          * during mounts. For global heartbeat, the threshold doubled for the
1773          * first region.
1774          */
1775         live_threshold = O2HB_LIVE_THRESHOLD;
1776         if (o2hb_global_heartbeat_active()) {
1777                 spin_lock(&o2hb_live_lock);
1778                 if (bitmap_weight(o2hb_region_bitmap, O2NM_MAX_REGIONS) == 1)
1779                         live_threshold <<= 1;
1780                 spin_unlock(&o2hb_live_lock);
1781         }
1782         ++live_threshold;
1783         atomic_set(&reg->hr_steady_iterations, live_threshold);
1784         /* unsteady_iterations is triple the steady_iterations */
1785         atomic_set(&reg->hr_unsteady_iterations, (live_threshold * 3));
1786
1787         hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
1788                               reg->hr_item.ci_name);
1789         if (IS_ERR(hb_task)) {
1790                 ret = PTR_ERR(hb_task);
1791                 mlog_errno(ret);
1792                 goto out3;
1793         }
1794
1795         spin_lock(&o2hb_live_lock);
1796         reg->hr_task = hb_task;
1797         spin_unlock(&o2hb_live_lock);
1798
1799         ret = wait_event_interruptible(o2hb_steady_queue,
1800                                 atomic_read(&reg->hr_steady_iterations) == 0 ||
1801                                 reg->hr_node_deleted);
1802         if (ret) {
1803                 atomic_set(&reg->hr_steady_iterations, 0);
1804                 reg->hr_aborted_start = 1;
1805         }
1806
1807         if (reg->hr_aborted_start) {
1808                 ret = -EIO;
1809                 goto out3;
1810         }
1811
1812         if (reg->hr_node_deleted) {
1813                 ret = -EINVAL;
1814                 goto out3;
1815         }
1816
1817         /* Ok, we were woken.  Make sure it wasn't by drop_item() */
1818         spin_lock(&o2hb_live_lock);
1819         hb_task = reg->hr_task;
1820         if (o2hb_global_heartbeat_active())
1821                 set_bit(reg->hr_region_num, o2hb_live_region_bitmap);
1822         spin_unlock(&o2hb_live_lock);
1823
1824         if (hb_task)
1825                 ret = count;
1826         else
1827                 ret = -EIO;
1828
1829         if (hb_task && o2hb_global_heartbeat_active())
1830                 printk(KERN_NOTICE "o2hb: Heartbeat started on region %s (%s)\n",
1831                        config_item_name(&reg->hr_item), reg->hr_dev_name);
1832
1833 out3:
1834         iput(inode);
1835 out2:
1836         fdput(f);
1837 out:
1838         if (ret < 0) {
1839                 if (reg->hr_bdev) {
1840                         blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1841                         reg->hr_bdev = NULL;
1842                 }
1843         }
1844         return ret;
1845 }
1846
1847 static ssize_t o2hb_region_pid_show(struct config_item *item, char *page)
1848 {
1849         struct o2hb_region *reg = to_o2hb_region(item);
1850         pid_t pid = 0;
1851
1852         spin_lock(&o2hb_live_lock);
1853         if (reg->hr_task)
1854                 pid = task_pid_nr(reg->hr_task);
1855         spin_unlock(&o2hb_live_lock);
1856
1857         if (!pid)
1858                 return 0;
1859
1860         return sprintf(page, "%u\n", pid);
1861 }
1862
1863 CONFIGFS_ATTR(o2hb_region_, block_bytes);
1864 CONFIGFS_ATTR(o2hb_region_, start_block);
1865 CONFIGFS_ATTR(o2hb_region_, blocks);
1866 CONFIGFS_ATTR(o2hb_region_, dev);
1867 CONFIGFS_ATTR_RO(o2hb_region_, pid);
1868
1869 static struct configfs_attribute *o2hb_region_attrs[] = {
1870         &o2hb_region_attr_block_bytes,
1871         &o2hb_region_attr_start_block,
1872         &o2hb_region_attr_blocks,
1873         &o2hb_region_attr_dev,
1874         &o2hb_region_attr_pid,
1875         NULL,
1876 };
1877
1878 static struct configfs_item_operations o2hb_region_item_ops = {
1879         .release                = o2hb_region_release,
1880 };
1881
1882 static struct config_item_type o2hb_region_type = {
1883         .ct_item_ops    = &o2hb_region_item_ops,
1884         .ct_attrs       = o2hb_region_attrs,
1885         .ct_owner       = THIS_MODULE,
1886 };
1887
1888 /* heartbeat set */
1889
1890 struct o2hb_heartbeat_group {
1891         struct config_group hs_group;
1892         /* some stuff? */
1893 };
1894
1895 static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
1896 {
1897         return group ?
1898                 container_of(group, struct o2hb_heartbeat_group, hs_group)
1899                 : NULL;
1900 }
1901
1902 static int o2hb_debug_region_init(struct o2hb_region *reg, struct dentry *dir)
1903 {
1904         int ret = -ENOMEM;
1905
1906         reg->hr_debug_dir =
1907                 debugfs_create_dir(config_item_name(&reg->hr_item), dir);
1908         if (!reg->hr_debug_dir) {
1909                 mlog_errno(ret);
1910                 goto bail;
1911         }
1912
1913         reg->hr_debug_livenodes =
1914                         o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1915                                           reg->hr_debug_dir,
1916                                           &(reg->hr_db_livenodes),
1917                                           sizeof(*(reg->hr_db_livenodes)),
1918                                           O2HB_DB_TYPE_REGION_LIVENODES,
1919                                           sizeof(reg->hr_live_node_bitmap),
1920                                           O2NM_MAX_NODES, reg);
1921         if (!reg->hr_debug_livenodes) {
1922                 mlog_errno(ret);
1923                 goto bail;
1924         }
1925
1926         reg->hr_debug_regnum =
1927                         o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER,
1928                                           reg->hr_debug_dir,
1929                                           &(reg->hr_db_regnum),
1930                                           sizeof(*(reg->hr_db_regnum)),
1931                                           O2HB_DB_TYPE_REGION_NUMBER,
1932                                           0, O2NM_MAX_NODES, reg);
1933         if (!reg->hr_debug_regnum) {
1934                 mlog_errno(ret);
1935                 goto bail;
1936         }
1937
1938         reg->hr_debug_elapsed_time =
1939                         o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME,
1940                                           reg->hr_debug_dir,
1941                                           &(reg->hr_db_elapsed_time),
1942                                           sizeof(*(reg->hr_db_elapsed_time)),
1943                                           O2HB_DB_TYPE_REGION_ELAPSED_TIME,
1944                                           0, 0, reg);
1945         if (!reg->hr_debug_elapsed_time) {
1946                 mlog_errno(ret);
1947                 goto bail;
1948         }
1949
1950         reg->hr_debug_pinned =
1951                         o2hb_debug_create(O2HB_DEBUG_REGION_PINNED,
1952                                           reg->hr_debug_dir,
1953                                           &(reg->hr_db_pinned),
1954                                           sizeof(*(reg->hr_db_pinned)),
1955                                           O2HB_DB_TYPE_REGION_PINNED,
1956                                           0, 0, reg);
1957         if (!reg->hr_debug_pinned) {
1958                 mlog_errno(ret);
1959                 goto bail;
1960         }
1961
1962         ret = 0;
1963 bail:
1964         return ret;
1965 }
1966
1967 static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
1968                                                           const char *name)
1969 {
1970         struct o2hb_region *reg = NULL;
1971         int ret;
1972
1973         reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
1974         if (reg == NULL)
1975                 return ERR_PTR(-ENOMEM);
1976
1977         if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
1978                 ret = -ENAMETOOLONG;
1979                 goto free;
1980         }
1981
1982         spin_lock(&o2hb_live_lock);
1983         reg->hr_region_num = 0;
1984         if (o2hb_global_heartbeat_active()) {
1985                 reg->hr_region_num = find_first_zero_bit(o2hb_region_bitmap,
1986                                                          O2NM_MAX_REGIONS);
1987                 if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
1988                         spin_unlock(&o2hb_live_lock);
1989                         ret = -EFBIG;
1990                         goto free;
1991                 }
1992                 set_bit(reg->hr_region_num, o2hb_region_bitmap);
1993         }
1994         list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
1995         spin_unlock(&o2hb_live_lock);
1996
1997         config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
1998
1999         ret = o2hb_debug_region_init(reg, o2hb_debug_dir);
2000         if (ret) {
2001                 config_item_put(&reg->hr_item);
2002                 goto free;
2003         }
2004
2005         return &reg->hr_item;
2006 free:
2007         kfree(reg);
2008         return ERR_PTR(ret);
2009 }
2010
2011 static void o2hb_heartbeat_group_drop_item(struct config_group *group,
2012                                            struct config_item *item)
2013 {
2014         struct task_struct *hb_task;
2015         struct o2hb_region *reg = to_o2hb_region(item);
2016         int quorum_region = 0;
2017
2018         /* stop the thread when the user removes the region dir */
2019         spin_lock(&o2hb_live_lock);
2020         hb_task = reg->hr_task;
2021         reg->hr_task = NULL;
2022         reg->hr_item_dropped = 1;
2023         spin_unlock(&o2hb_live_lock);
2024
2025         if (hb_task)
2026                 kthread_stop(hb_task);
2027
2028         if (o2hb_global_heartbeat_active()) {
2029                 spin_lock(&o2hb_live_lock);
2030                 clear_bit(reg->hr_region_num, o2hb_region_bitmap);
2031                 clear_bit(reg->hr_region_num, o2hb_live_region_bitmap);
2032                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
2033                         quorum_region = 1;
2034                 clear_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
2035                 spin_unlock(&o2hb_live_lock);
2036                 printk(KERN_NOTICE "o2hb: Heartbeat %s on region %s (%s)\n",
2037                        ((atomic_read(&reg->hr_steady_iterations) == 0) ?
2038                         "stopped" : "start aborted"), config_item_name(item),
2039                        reg->hr_dev_name);
2040         }
2041
2042         /*
2043          * If we're racing a dev_write(), we need to wake them.  They will
2044          * check reg->hr_task
2045          */
2046         if (atomic_read(&reg->hr_steady_iterations) != 0) {
2047                 reg->hr_aborted_start = 1;
2048                 atomic_set(&reg->hr_steady_iterations, 0);
2049                 wake_up(&o2hb_steady_queue);
2050         }
2051
2052         config_item_put(item);
2053
2054         if (!o2hb_global_heartbeat_active() || !quorum_region)
2055                 return;
2056
2057         /*
2058          * If global heartbeat active and there are dependent users,
2059          * pin all regions if quorum region count <= CUT_OFF
2060          */
2061         spin_lock(&o2hb_live_lock);
2062
2063         if (!o2hb_dependent_users)
2064                 goto unlock;
2065
2066         if (bitmap_weight(o2hb_quorum_region_bitmap,
2067                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2068                 o2hb_region_pin(NULL);
2069
2070 unlock:
2071         spin_unlock(&o2hb_live_lock);
2072 }
2073
2074 static ssize_t o2hb_heartbeat_group_threshold_show(struct config_item *item,
2075                 char *page)
2076 {
2077         return sprintf(page, "%u\n", o2hb_dead_threshold);
2078 }
2079
2080 static ssize_t o2hb_heartbeat_group_threshold_store(struct config_item *item,
2081                 const char *page, size_t count)
2082 {
2083         unsigned long tmp;
2084         char *p = (char *)page;
2085
2086         tmp = simple_strtoul(p, &p, 10);
2087         if (!p || (*p && (*p != '\n')))
2088                 return -EINVAL;
2089
2090         /* this will validate ranges for us. */
2091         o2hb_dead_threshold_set((unsigned int) tmp);
2092
2093         return count;
2094 }
2095
2096 static ssize_t o2hb_heartbeat_group_mode_show(struct config_item *item,
2097                 char *page)
2098 {
2099         return sprintf(page, "%s\n",
2100                        o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
2101 }
2102
2103 static ssize_t o2hb_heartbeat_group_mode_store(struct config_item *item,
2104                 const char *page, size_t count)
2105 {
2106         unsigned int i;
2107         int ret;
2108         size_t len;
2109
2110         len = (page[count - 1] == '\n') ? count - 1 : count;
2111         if (!len)
2112                 return -EINVAL;
2113
2114         for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
2115                 if (strncasecmp(page, o2hb_heartbeat_mode_desc[i], len))
2116                         continue;
2117
2118                 ret = o2hb_global_heartbeat_mode_set(i);
2119                 if (!ret)
2120                         printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
2121                                o2hb_heartbeat_mode_desc[i]);
2122                 return count;
2123         }
2124
2125         return -EINVAL;
2126
2127 }
2128
2129 CONFIGFS_ATTR(o2hb_heartbeat_group_, threshold);
2130 CONFIGFS_ATTR(o2hb_heartbeat_group_, mode);
2131
2132 static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
2133         &o2hb_heartbeat_group_attr_threshold,
2134         &o2hb_heartbeat_group_attr_mode,
2135         NULL,
2136 };
2137
2138 static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
2139         .make_item      = o2hb_heartbeat_group_make_item,
2140         .drop_item      = o2hb_heartbeat_group_drop_item,
2141 };
2142
2143 static struct config_item_type o2hb_heartbeat_group_type = {
2144         .ct_group_ops   = &o2hb_heartbeat_group_group_ops,
2145         .ct_attrs       = o2hb_heartbeat_group_attrs,
2146         .ct_owner       = THIS_MODULE,
2147 };
2148
2149 /* this is just here to avoid touching group in heartbeat.h which the
2150  * entire damn world #includes */
2151 struct config_group *o2hb_alloc_hb_set(void)
2152 {
2153         struct o2hb_heartbeat_group *hs = NULL;
2154         struct config_group *ret = NULL;
2155
2156         hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
2157         if (hs == NULL)
2158                 goto out;
2159
2160         config_group_init_type_name(&hs->hs_group, "heartbeat",
2161                                     &o2hb_heartbeat_group_type);
2162
2163         ret = &hs->hs_group;
2164 out:
2165         if (ret == NULL)
2166                 kfree(hs);
2167         return ret;
2168 }
2169
2170 void o2hb_free_hb_set(struct config_group *group)
2171 {
2172         struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
2173         kfree(hs);
2174 }
2175
2176 /* hb callback registration and issuing */
2177
2178 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
2179 {
2180         if (type == O2HB_NUM_CB)
2181                 return ERR_PTR(-EINVAL);
2182
2183         return &o2hb_callbacks[type];
2184 }
2185
2186 void o2hb_setup_callback(struct o2hb_callback_func *hc,
2187                          enum o2hb_callback_type type,
2188                          o2hb_cb_func *func,
2189                          void *data,
2190                          int priority)
2191 {
2192         INIT_LIST_HEAD(&hc->hc_item);
2193         hc->hc_func = func;
2194         hc->hc_data = data;
2195         hc->hc_priority = priority;
2196         hc->hc_type = type;
2197         hc->hc_magic = O2HB_CB_MAGIC;
2198 }
2199 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
2200
2201 /*
2202  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2203  * In global heartbeat mode, region_uuid passed is NULL.
2204  *
2205  * In local, we only pin the matching region. In global we pin all the active
2206  * regions.
2207  */
2208 static int o2hb_region_pin(const char *region_uuid)
2209 {
2210         int ret = 0, found = 0;
2211         struct o2hb_region *reg;
2212         char *uuid;
2213
2214         assert_spin_locked(&o2hb_live_lock);
2215
2216         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2217                 if (reg->hr_item_dropped)
2218                         continue;
2219
2220                 uuid = config_item_name(&reg->hr_item);
2221
2222                 /* local heartbeat */
2223                 if (region_uuid) {
2224                         if (strcmp(region_uuid, uuid))
2225                                 continue;
2226                         found = 1;
2227                 }
2228
2229                 if (reg->hr_item_pinned || reg->hr_item_dropped)
2230                         goto skip_pin;
2231
2232                 /* Ignore ENOENT only for local hb (userdlm domain) */
2233                 ret = o2nm_depend_item(&reg->hr_item);
2234                 if (!ret) {
2235                         mlog(ML_CLUSTER, "Pin region %s\n", uuid);
2236                         reg->hr_item_pinned = 1;
2237                 } else {
2238                         if (ret == -ENOENT && found)
2239                                 ret = 0;
2240                         else {
2241                                 mlog(ML_ERROR, "Pin region %s fails with %d\n",
2242                                      uuid, ret);
2243                                 break;
2244                         }
2245                 }
2246 skip_pin:
2247                 if (found)
2248                         break;
2249         }
2250
2251         return ret;
2252 }
2253
2254 /*
2255  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2256  * In global heartbeat mode, region_uuid passed is NULL.
2257  *
2258  * In local, we only unpin the matching region. In global we unpin all the
2259  * active regions.
2260  */
2261 static void o2hb_region_unpin(const char *region_uuid)
2262 {
2263         struct o2hb_region *reg;
2264         char *uuid;
2265         int found = 0;
2266
2267         assert_spin_locked(&o2hb_live_lock);
2268
2269         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2270                 if (reg->hr_item_dropped)
2271                         continue;
2272
2273                 uuid = config_item_name(&reg->hr_item);
2274                 if (region_uuid) {
2275                         if (strcmp(region_uuid, uuid))
2276                                 continue;
2277                         found = 1;
2278                 }
2279
2280                 if (reg->hr_item_pinned) {
2281                         mlog(ML_CLUSTER, "Unpin region %s\n", uuid);
2282                         o2nm_undepend_item(&reg->hr_item);
2283                         reg->hr_item_pinned = 0;
2284                 }
2285                 if (found)
2286                         break;
2287         }
2288 }
2289
2290 static int o2hb_region_inc_user(const char *region_uuid)
2291 {
2292         int ret = 0;
2293
2294         spin_lock(&o2hb_live_lock);
2295
2296         /* local heartbeat */
2297         if (!o2hb_global_heartbeat_active()) {
2298             ret = o2hb_region_pin(region_uuid);
2299             goto unlock;
2300         }
2301
2302         /*
2303          * if global heartbeat active and this is the first dependent user,
2304          * pin all regions if quorum region count <= CUT_OFF
2305          */
2306         o2hb_dependent_users++;
2307         if (o2hb_dependent_users > 1)
2308                 goto unlock;
2309
2310         if (bitmap_weight(o2hb_quorum_region_bitmap,
2311                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2312                 ret = o2hb_region_pin(NULL);
2313
2314 unlock:
2315         spin_unlock(&o2hb_live_lock);
2316         return ret;
2317 }
2318
2319 void o2hb_region_dec_user(const char *region_uuid)
2320 {
2321         spin_lock(&o2hb_live_lock);
2322
2323         /* local heartbeat */
2324         if (!o2hb_global_heartbeat_active()) {
2325             o2hb_region_unpin(region_uuid);
2326             goto unlock;
2327         }
2328
2329         /*
2330          * if global heartbeat active and there are no dependent users,
2331          * unpin all quorum regions
2332          */
2333         o2hb_dependent_users--;
2334         if (!o2hb_dependent_users)
2335                 o2hb_region_unpin(NULL);
2336
2337 unlock:
2338         spin_unlock(&o2hb_live_lock);
2339 }
2340
2341 int o2hb_register_callback(const char *region_uuid,
2342                            struct o2hb_callback_func *hc)
2343 {
2344         struct o2hb_callback_func *f;
2345         struct o2hb_callback *hbcall;
2346         int ret;
2347
2348         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2349         BUG_ON(!list_empty(&hc->hc_item));
2350
2351         hbcall = hbcall_from_type(hc->hc_type);
2352         if (IS_ERR(hbcall)) {
2353                 ret = PTR_ERR(hbcall);
2354                 goto out;
2355         }
2356
2357         if (region_uuid) {
2358                 ret = o2hb_region_inc_user(region_uuid);
2359                 if (ret) {
2360                         mlog_errno(ret);
2361                         goto out;
2362                 }
2363         }
2364
2365         down_write(&o2hb_callback_sem);
2366
2367         list_for_each_entry(f, &hbcall->list, hc_item) {
2368                 if (hc->hc_priority < f->hc_priority) {
2369                         list_add_tail(&hc->hc_item, &f->hc_item);
2370                         break;
2371                 }
2372         }
2373         if (list_empty(&hc->hc_item))
2374                 list_add_tail(&hc->hc_item, &hbcall->list);
2375
2376         up_write(&o2hb_callback_sem);
2377         ret = 0;
2378 out:
2379         mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
2380              ret, __builtin_return_address(0), hc);
2381         return ret;
2382 }
2383 EXPORT_SYMBOL_GPL(o2hb_register_callback);
2384
2385 void o2hb_unregister_callback(const char *region_uuid,
2386                               struct o2hb_callback_func *hc)
2387 {
2388         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2389
2390         mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
2391              __builtin_return_address(0), hc);
2392
2393         /* XXX Can this happen _with_ a region reference? */
2394         if (list_empty(&hc->hc_item))
2395                 return;
2396
2397         if (region_uuid)
2398                 o2hb_region_dec_user(region_uuid);
2399
2400         down_write(&o2hb_callback_sem);
2401
2402         list_del_init(&hc->hc_item);
2403
2404         up_write(&o2hb_callback_sem);
2405 }
2406 EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
2407
2408 int o2hb_check_node_heartbeating(u8 node_num)
2409 {
2410         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2411
2412         o2hb_fill_node_map(testing_map, sizeof(testing_map));
2413         if (!test_bit(node_num, testing_map)) {
2414                 mlog(ML_HEARTBEAT,
2415                      "node (%u) does not have heartbeating enabled.\n",
2416                      node_num);
2417                 return 0;
2418         }
2419
2420         return 1;
2421 }
2422 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating);
2423
2424 int o2hb_check_node_heartbeating_no_sem(u8 node_num)
2425 {
2426         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2427
2428         spin_lock(&o2hb_live_lock);
2429         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2430         spin_unlock(&o2hb_live_lock);
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);