linux/fs/ocfs2/cluster/heartbeat.c
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   1/* -*- mode: c; c-basic-offset: 8; -*-
   2 * vim: noexpandtab sw=8 ts=8 sts=0:
   3 *
   4 * Copyright (C) 2004, 2005 Oracle.  All rights reserved.
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public
   8 * License as published by the Free Software Foundation; either
   9 * version 2 of the License, or (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 * General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public
  17 * License along with this program; if not, write to the
  18 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19 * Boston, MA 021110-1307, USA.
  20 */
  21
  22#include <linux/kernel.h>
  23#include <linux/sched.h>
  24#include <linux/jiffies.h>
  25#include <linux/module.h>
  26#include <linux/fs.h>
  27#include <linux/bio.h>
  28#include <linux/blkdev.h>
  29#include <linux/delay.h>
  30#include <linux/file.h>
  31#include <linux/kthread.h>
  32#include <linux/configfs.h>
  33#include <linux/random.h>
  34#include <linux/crc32.h>
  35#include <linux/time.h>
  36#include <linux/debugfs.h>
  37#include <linux/slab.h>
  38
  39#include "heartbeat.h"
  40#include "tcp.h"
  41#include "nodemanager.h"
  42#include "quorum.h"
  43
  44#include "masklog.h"
  45
  46
  47/*
  48 * The first heartbeat pass had one global thread that would serialize all hb
  49 * callback calls.  This global serializing sem should only be removed once
  50 * we've made sure that all callees can deal with being called concurrently
  51 * from multiple hb region threads.
  52 */
  53static DECLARE_RWSEM(o2hb_callback_sem);
  54
  55/*
  56 * multiple hb threads are watching multiple regions.  A node is live
  57 * whenever any of the threads sees activity from the node in its region.
  58 */
  59static DEFINE_SPINLOCK(o2hb_live_lock);
  60static struct list_head o2hb_live_slots[O2NM_MAX_NODES];
  61static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
  62static LIST_HEAD(o2hb_node_events);
  63static DECLARE_WAIT_QUEUE_HEAD(o2hb_steady_queue);
  64
  65/*
  66 * In global heartbeat, we maintain a series of region bitmaps.
  67 *      - o2hb_region_bitmap allows us to limit the region number to max region.
  68 *      - o2hb_live_region_bitmap tracks live regions (seen steady iterations).
  69 *      - o2hb_quorum_region_bitmap tracks live regions that have seen all nodes
  70 *              heartbeat on it.
  71 *      - o2hb_failed_region_bitmap tracks the regions that have seen io timeouts.
  72 */
  73static unsigned long o2hb_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  74static unsigned long o2hb_live_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  75static unsigned long o2hb_quorum_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  76static unsigned long o2hb_failed_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  77
  78#define O2HB_DB_TYPE_LIVENODES          0
  79#define O2HB_DB_TYPE_LIVEREGIONS        1
  80#define O2HB_DB_TYPE_QUORUMREGIONS      2
  81#define O2HB_DB_TYPE_FAILEDREGIONS      3
  82#define O2HB_DB_TYPE_REGION_LIVENODES   4
  83#define O2HB_DB_TYPE_REGION_NUMBER      5
  84#define O2HB_DB_TYPE_REGION_ELAPSED_TIME        6
  85#define O2HB_DB_TYPE_REGION_PINNED      7
  86struct o2hb_debug_buf {
  87        int db_type;
  88        int db_size;
  89        int db_len;
  90        void *db_data;
  91};
  92
  93static struct o2hb_debug_buf *o2hb_db_livenodes;
  94static struct o2hb_debug_buf *o2hb_db_liveregions;
  95static struct o2hb_debug_buf *o2hb_db_quorumregions;
  96static struct o2hb_debug_buf *o2hb_db_failedregions;
  97
  98#define O2HB_DEBUG_DIR                  "o2hb"
  99#define O2HB_DEBUG_LIVENODES            "livenodes"
 100#define O2HB_DEBUG_LIVEREGIONS          "live_regions"
 101#define O2HB_DEBUG_QUORUMREGIONS        "quorum_regions"
 102#define O2HB_DEBUG_FAILEDREGIONS        "failed_regions"
 103#define O2HB_DEBUG_REGION_NUMBER        "num"
 104#define O2HB_DEBUG_REGION_ELAPSED_TIME  "elapsed_time_in_ms"
 105#define O2HB_DEBUG_REGION_PINNED        "pinned"
 106
 107static struct dentry *o2hb_debug_dir;
 108static struct dentry *o2hb_debug_livenodes;
 109static struct dentry *o2hb_debug_liveregions;
 110static struct dentry *o2hb_debug_quorumregions;
 111static struct dentry *o2hb_debug_failedregions;
 112
 113static LIST_HEAD(o2hb_all_regions);
 114
 115static struct o2hb_callback {
 116        struct list_head list;
 117} o2hb_callbacks[O2HB_NUM_CB];
 118
 119static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type);
 120
 121#define O2HB_DEFAULT_BLOCK_BITS       9
 122
 123enum o2hb_heartbeat_modes {
 124        O2HB_HEARTBEAT_LOCAL            = 0,
 125        O2HB_HEARTBEAT_GLOBAL,
 126        O2HB_HEARTBEAT_NUM_MODES,
 127};
 128
 129char *o2hb_heartbeat_mode_desc[O2HB_HEARTBEAT_NUM_MODES] = {
 130                "local",        /* O2HB_HEARTBEAT_LOCAL */
 131                "global",       /* O2HB_HEARTBEAT_GLOBAL */
 132};
 133
 134unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
 135unsigned int o2hb_heartbeat_mode = O2HB_HEARTBEAT_LOCAL;
 136
 137/*
 138 * o2hb_dependent_users tracks the number of registered callbacks that depend
 139 * on heartbeat. o2net and o2dlm are two entities that register this callback.
 140 * However only o2dlm depends on the heartbeat. It does not want the heartbeat
 141 * to stop while a dlm domain is still active.
 142 */
 143unsigned int o2hb_dependent_users;
 144
 145/*
 146 * In global heartbeat mode, all regions are pinned if there are one or more
 147 * dependent users and the quorum region count is <= O2HB_PIN_CUT_OFF. All
 148 * regions are unpinned if the region count exceeds the cut off or the number
 149 * of dependent users falls to zero.
 150 */
 151#define O2HB_PIN_CUT_OFF                3
 152
 153/*
 154 * In local heartbeat mode, we assume the dlm domain name to be the same as
 155 * region uuid. This is true for domains created for the file system but not
 156 * necessarily true for userdlm domains. This is a known limitation.
 157 *
 158 * In global heartbeat mode, we pin/unpin all o2hb regions. This solution
 159 * works for both file system and userdlm domains.
 160 */
 161static int o2hb_region_pin(const char *region_uuid);
 162static void o2hb_region_unpin(const char *region_uuid);
 163
 164/* Only sets a new threshold if there are no active regions.
 165 *
 166 * No locking or otherwise interesting code is required for reading
 167 * o2hb_dead_threshold as it can't change once regions are active and
 168 * it's not interesting to anyone until then anyway. */
 169static void o2hb_dead_threshold_set(unsigned int threshold)
 170{
 171        if (threshold > O2HB_MIN_DEAD_THRESHOLD) {
 172                spin_lock(&o2hb_live_lock);
 173                if (list_empty(&o2hb_all_regions))
 174                        o2hb_dead_threshold = threshold;
 175                spin_unlock(&o2hb_live_lock);
 176        }
 177}
 178
 179static int o2hb_global_hearbeat_mode_set(unsigned int hb_mode)
 180{
 181        int ret = -1;
 182
 183        if (hb_mode < O2HB_HEARTBEAT_NUM_MODES) {
 184                spin_lock(&o2hb_live_lock);
 185                if (list_empty(&o2hb_all_regions)) {
 186                        o2hb_heartbeat_mode = hb_mode;
 187                        ret = 0;
 188                }
 189                spin_unlock(&o2hb_live_lock);
 190        }
 191
 192        return ret;
 193}
 194
 195struct o2hb_node_event {
 196        struct list_head        hn_item;
 197        enum o2hb_callback_type hn_event_type;
 198        struct o2nm_node        *hn_node;
 199        int                     hn_node_num;
 200};
 201
 202struct o2hb_disk_slot {
 203        struct o2hb_disk_heartbeat_block *ds_raw_block;
 204        u8                      ds_node_num;
 205        u64                     ds_last_time;
 206        u64                     ds_last_generation;
 207        u16                     ds_equal_samples;
 208        u16                     ds_changed_samples;
 209        struct list_head        ds_live_item;
 210};
 211
 212/* each thread owns a region.. when we're asked to tear down the region
 213 * we ask the thread to stop, who cleans up the region */
 214struct o2hb_region {
 215        struct config_item      hr_item;
 216
 217        struct list_head        hr_all_item;
 218        unsigned                hr_unclean_stop:1,
 219                                hr_aborted_start:1,
 220                                hr_item_pinned:1,
 221                                hr_item_dropped:1;
 222
 223        /* protected by the hr_callback_sem */
 224        struct task_struct      *hr_task;
 225
 226        unsigned int            hr_blocks;
 227        unsigned long long      hr_start_block;
 228
 229        unsigned int            hr_block_bits;
 230        unsigned int            hr_block_bytes;
 231
 232        unsigned int            hr_slots_per_page;
 233        unsigned int            hr_num_pages;
 234
 235        struct page             **hr_slot_data;
 236        struct block_device     *hr_bdev;
 237        struct o2hb_disk_slot   *hr_slots;
 238
 239        /* live node map of this region */
 240        unsigned long           hr_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 241        unsigned int            hr_region_num;
 242
 243        struct dentry           *hr_debug_dir;
 244        struct dentry           *hr_debug_livenodes;
 245        struct dentry           *hr_debug_regnum;
 246        struct dentry           *hr_debug_elapsed_time;
 247        struct dentry           *hr_debug_pinned;
 248        struct o2hb_debug_buf   *hr_db_livenodes;
 249        struct o2hb_debug_buf   *hr_db_regnum;
 250        struct o2hb_debug_buf   *hr_db_elapsed_time;
 251        struct o2hb_debug_buf   *hr_db_pinned;
 252
 253        /* let the person setting up hb wait for it to return until it
 254         * has reached a 'steady' state.  This will be fixed when we have
 255         * a more complete api that doesn't lead to this sort of fragility. */
 256        atomic_t                hr_steady_iterations;
 257
 258        /* terminate o2hb thread if it does not reach steady state
 259         * (hr_steady_iterations == 0) within hr_unsteady_iterations */
 260        atomic_t                hr_unsteady_iterations;
 261
 262        char                    hr_dev_name[BDEVNAME_SIZE];
 263
 264        unsigned int            hr_timeout_ms;
 265
 266        /* randomized as the region goes up and down so that a node
 267         * recognizes a node going up and down in one iteration */
 268        u64                     hr_generation;
 269
 270        struct delayed_work     hr_write_timeout_work;
 271        unsigned long           hr_last_timeout_start;
 272
 273        /* Used during o2hb_check_slot to hold a copy of the block
 274         * being checked because we temporarily have to zero out the
 275         * crc field. */
 276        struct o2hb_disk_heartbeat_block *hr_tmp_block;
 277};
 278
 279struct o2hb_bio_wait_ctxt {
 280        atomic_t          wc_num_reqs;
 281        struct completion wc_io_complete;
 282        int               wc_error;
 283};
 284
 285static int o2hb_pop_count(void *map, int count)
 286{
 287        int i = -1, pop = 0;
 288
 289        while ((i = find_next_bit(map, count, i + 1)) < count)
 290                pop++;
 291        return pop;
 292}
 293
 294static void o2hb_write_timeout(struct work_struct *work)
 295{
 296        int failed, quorum;
 297        unsigned long flags;
 298        struct o2hb_region *reg =
 299                container_of(work, struct o2hb_region,
 300                             hr_write_timeout_work.work);
 301
 302        mlog(ML_ERROR, "Heartbeat write timeout to device %s after %u "
 303             "milliseconds\n", reg->hr_dev_name,
 304             jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
 305
 306        if (o2hb_global_heartbeat_active()) {
 307                spin_lock_irqsave(&o2hb_live_lock, flags);
 308                if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 309                        set_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 310                failed = o2hb_pop_count(&o2hb_failed_region_bitmap,
 311                                        O2NM_MAX_REGIONS);
 312                quorum = o2hb_pop_count(&o2hb_quorum_region_bitmap,
 313                                        O2NM_MAX_REGIONS);
 314                spin_unlock_irqrestore(&o2hb_live_lock, flags);
 315
 316                mlog(ML_HEARTBEAT, "Number of regions %d, failed regions %d\n",
 317                     quorum, failed);
 318
 319                /*
 320                 * Fence if the number of failed regions >= half the number
 321                 * of  quorum regions
 322                 */
 323                if ((failed << 1) < quorum)
 324                        return;
 325        }
 326
 327        o2quo_disk_timeout();
 328}
 329
 330static void o2hb_arm_write_timeout(struct o2hb_region *reg)
 331{
 332        /* Arm writeout only after thread reaches steady state */
 333        if (atomic_read(&reg->hr_steady_iterations) != 0)
 334                return;
 335
 336        mlog(ML_HEARTBEAT, "Queue write timeout for %u ms\n",
 337             O2HB_MAX_WRITE_TIMEOUT_MS);
 338
 339        if (o2hb_global_heartbeat_active()) {
 340                spin_lock(&o2hb_live_lock);
 341                clear_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 342                spin_unlock(&o2hb_live_lock);
 343        }
 344        cancel_delayed_work(&reg->hr_write_timeout_work);
 345        reg->hr_last_timeout_start = jiffies;
 346        schedule_delayed_work(&reg->hr_write_timeout_work,
 347                              msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
 348}
 349
 350static void o2hb_disarm_write_timeout(struct o2hb_region *reg)
 351{
 352        cancel_delayed_work_sync(&reg->hr_write_timeout_work);
 353}
 354
 355static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
 356{
 357        atomic_set(&wc->wc_num_reqs, 1);
 358        init_completion(&wc->wc_io_complete);
 359        wc->wc_error = 0;
 360}
 361
 362/* Used in error paths too */
 363static inline void o2hb_bio_wait_dec(struct o2hb_bio_wait_ctxt *wc,
 364                                     unsigned int num)
 365{
 366        /* sadly atomic_sub_and_test() isn't available on all platforms.  The
 367         * good news is that the fast path only completes one at a time */
 368        while(num--) {
 369                if (atomic_dec_and_test(&wc->wc_num_reqs)) {
 370                        BUG_ON(num > 0);
 371                        complete(&wc->wc_io_complete);
 372                }
 373        }
 374}
 375
 376static void o2hb_wait_on_io(struct o2hb_region *reg,
 377                            struct o2hb_bio_wait_ctxt *wc)
 378{
 379        o2hb_bio_wait_dec(wc, 1);
 380        wait_for_completion(&wc->wc_io_complete);
 381}
 382
 383static void o2hb_bio_end_io(struct bio *bio,
 384                           int error)
 385{
 386        struct o2hb_bio_wait_ctxt *wc = bio->bi_private;
 387
 388        if (error) {
 389                mlog(ML_ERROR, "IO Error %d\n", error);
 390                wc->wc_error = error;
 391        }
 392
 393        o2hb_bio_wait_dec(wc, 1);
 394        bio_put(bio);
 395}
 396
 397/* Setup a Bio to cover I/O against num_slots slots starting at
 398 * start_slot. */
 399static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
 400                                      struct o2hb_bio_wait_ctxt *wc,
 401                                      unsigned int *current_slot,
 402                                      unsigned int max_slots)
 403{
 404        int len, current_page;
 405        unsigned int vec_len, vec_start;
 406        unsigned int bits = reg->hr_block_bits;
 407        unsigned int spp = reg->hr_slots_per_page;
 408        unsigned int cs = *current_slot;
 409        struct bio *bio;
 410        struct page *page;
 411
 412        /* Testing has shown this allocation to take long enough under
 413         * GFP_KERNEL that the local node can get fenced. It would be
 414         * nicest if we could pre-allocate these bios and avoid this
 415         * all together. */
 416        bio = bio_alloc(GFP_ATOMIC, 16);
 417        if (!bio) {
 418                mlog(ML_ERROR, "Could not alloc slots BIO!\n");
 419                bio = ERR_PTR(-ENOMEM);
 420                goto bail;
 421        }
 422
 423        /* Must put everything in 512 byte sectors for the bio... */
 424        bio->bi_sector = (reg->hr_start_block + cs) << (bits - 9);
 425        bio->bi_bdev = reg->hr_bdev;
 426        bio->bi_private = wc;
 427        bio->bi_end_io = o2hb_bio_end_io;
 428
 429        vec_start = (cs << bits) % PAGE_CACHE_SIZE;
 430        while(cs < max_slots) {
 431                current_page = cs / spp;
 432                page = reg->hr_slot_data[current_page];
 433
 434                vec_len = min(PAGE_CACHE_SIZE - vec_start,
 435                              (max_slots-cs) * (PAGE_CACHE_SIZE/spp) );
 436
 437                mlog(ML_HB_BIO, "page %d, vec_len = %u, vec_start = %u\n",
 438                     current_page, vec_len, vec_start);
 439
 440                len = bio_add_page(bio, page, vec_len, vec_start);
 441                if (len != vec_len) break;
 442
 443                cs += vec_len / (PAGE_CACHE_SIZE/spp);
 444                vec_start = 0;
 445        }
 446
 447bail:
 448        *current_slot = cs;
 449        return bio;
 450}
 451
 452static int o2hb_read_slots(struct o2hb_region *reg,
 453                           unsigned int max_slots)
 454{
 455        unsigned int current_slot=0;
 456        int status;
 457        struct o2hb_bio_wait_ctxt wc;
 458        struct bio *bio;
 459
 460        o2hb_bio_wait_init(&wc);
 461
 462        while(current_slot < max_slots) {
 463                bio = o2hb_setup_one_bio(reg, &wc, &current_slot, max_slots);
 464                if (IS_ERR(bio)) {
 465                        status = PTR_ERR(bio);
 466                        mlog_errno(status);
 467                        goto bail_and_wait;
 468                }
 469
 470                atomic_inc(&wc.wc_num_reqs);
 471                submit_bio(READ, bio);
 472        }
 473
 474        status = 0;
 475
 476bail_and_wait:
 477        o2hb_wait_on_io(reg, &wc);
 478        if (wc.wc_error && !status)
 479                status = wc.wc_error;
 480
 481        return status;
 482}
 483
 484static int o2hb_issue_node_write(struct o2hb_region *reg,
 485                                 struct o2hb_bio_wait_ctxt *write_wc)
 486{
 487        int status;
 488        unsigned int slot;
 489        struct bio *bio;
 490
 491        o2hb_bio_wait_init(write_wc);
 492
 493        slot = o2nm_this_node();
 494
 495        bio = o2hb_setup_one_bio(reg, write_wc, &slot, slot+1);
 496        if (IS_ERR(bio)) {
 497                status = PTR_ERR(bio);
 498                mlog_errno(status);
 499                goto bail;
 500        }
 501
 502        atomic_inc(&write_wc->wc_num_reqs);
 503        submit_bio(WRITE, bio);
 504
 505        status = 0;
 506bail:
 507        return status;
 508}
 509
 510static u32 o2hb_compute_block_crc_le(struct o2hb_region *reg,
 511                                     struct o2hb_disk_heartbeat_block *hb_block)
 512{
 513        __le32 old_cksum;
 514        u32 ret;
 515
 516        /* We want to compute the block crc with a 0 value in the
 517         * hb_cksum field. Save it off here and replace after the
 518         * crc. */
 519        old_cksum = hb_block->hb_cksum;
 520        hb_block->hb_cksum = 0;
 521
 522        ret = crc32_le(0, (unsigned char *) hb_block, reg->hr_block_bytes);
 523
 524        hb_block->hb_cksum = old_cksum;
 525
 526        return ret;
 527}
 528
 529static void o2hb_dump_slot(struct o2hb_disk_heartbeat_block *hb_block)
 530{
 531        mlog(ML_ERROR, "Dump slot information: seq = 0x%llx, node = %u, "
 532             "cksum = 0x%x, generation 0x%llx\n",
 533             (long long)le64_to_cpu(hb_block->hb_seq),
 534             hb_block->hb_node, le32_to_cpu(hb_block->hb_cksum),
 535             (long long)le64_to_cpu(hb_block->hb_generation));
 536}
 537
 538static int o2hb_verify_crc(struct o2hb_region *reg,
 539                           struct o2hb_disk_heartbeat_block *hb_block)
 540{
 541        u32 read, computed;
 542
 543        read = le32_to_cpu(hb_block->hb_cksum);
 544        computed = o2hb_compute_block_crc_le(reg, hb_block);
 545
 546        return read == computed;
 547}
 548
 549/*
 550 * Compare the slot data with what we wrote in the last iteration.
 551 * If the match fails, print an appropriate error message. This is to
 552 * detect errors like... another node hearting on the same slot,
 553 * flaky device that is losing writes, etc.
 554 * Returns 1 if check succeeds, 0 otherwise.
 555 */
 556static int o2hb_check_own_slot(struct o2hb_region *reg)
 557{
 558        struct o2hb_disk_slot *slot;
 559        struct o2hb_disk_heartbeat_block *hb_block;
 560        char *errstr;
 561
 562        slot = &reg->hr_slots[o2nm_this_node()];
 563        /* Don't check on our 1st timestamp */
 564        if (!slot->ds_last_time)
 565                return 0;
 566
 567        hb_block = slot->ds_raw_block;
 568        if (le64_to_cpu(hb_block->hb_seq) == slot->ds_last_time &&
 569            le64_to_cpu(hb_block->hb_generation) == slot->ds_last_generation &&
 570            hb_block->hb_node == slot->ds_node_num)
 571                return 1;
 572
 573#define ERRSTR1         "Another node is heartbeating on device"
 574#define ERRSTR2         "Heartbeat generation mismatch on device"
 575#define ERRSTR3         "Heartbeat sequence mismatch on device"
 576
 577        if (hb_block->hb_node != slot->ds_node_num)
 578                errstr = ERRSTR1;
 579        else if (le64_to_cpu(hb_block->hb_generation) !=
 580                 slot->ds_last_generation)
 581                errstr = ERRSTR2;
 582        else
 583                errstr = ERRSTR3;
 584
 585        mlog(ML_ERROR, "%s (%s): expected(%u:0x%llx, 0x%llx), "
 586             "ondisk(%u:0x%llx, 0x%llx)\n", errstr, reg->hr_dev_name,
 587             slot->ds_node_num, (unsigned long long)slot->ds_last_generation,
 588             (unsigned long long)slot->ds_last_time, hb_block->hb_node,
 589             (unsigned long long)le64_to_cpu(hb_block->hb_generation),
 590             (unsigned long long)le64_to_cpu(hb_block->hb_seq));
 591
 592        return 0;
 593}
 594
 595static inline void o2hb_prepare_block(struct o2hb_region *reg,
 596                                      u64 generation)
 597{
 598        int node_num;
 599        u64 cputime;
 600        struct o2hb_disk_slot *slot;
 601        struct o2hb_disk_heartbeat_block *hb_block;
 602
 603        node_num = o2nm_this_node();
 604        slot = &reg->hr_slots[node_num];
 605
 606        hb_block = (struct o2hb_disk_heartbeat_block *)slot->ds_raw_block;
 607        memset(hb_block, 0, reg->hr_block_bytes);
 608        /* TODO: time stuff */
 609        cputime = CURRENT_TIME.tv_sec;
 610        if (!cputime)
 611                cputime = 1;
 612
 613        hb_block->hb_seq = cpu_to_le64(cputime);
 614        hb_block->hb_node = node_num;
 615        hb_block->hb_generation = cpu_to_le64(generation);
 616        hb_block->hb_dead_ms = cpu_to_le32(o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS);
 617
 618        /* This step must always happen last! */
 619        hb_block->hb_cksum = cpu_to_le32(o2hb_compute_block_crc_le(reg,
 620                                                                   hb_block));
 621
 622        mlog(ML_HB_BIO, "our node generation = 0x%llx, cksum = 0x%x\n",
 623             (long long)generation,
 624             le32_to_cpu(hb_block->hb_cksum));
 625}
 626
 627static void o2hb_fire_callbacks(struct o2hb_callback *hbcall,
 628                                struct o2nm_node *node,
 629                                int idx)
 630{
 631        struct list_head *iter;
 632        struct o2hb_callback_func *f;
 633
 634        list_for_each(iter, &hbcall->list) {
 635                f = list_entry(iter, struct o2hb_callback_func, hc_item);
 636                mlog(ML_HEARTBEAT, "calling funcs %p\n", f);
 637                (f->hc_func)(node, idx, f->hc_data);
 638        }
 639}
 640
 641/* Will run the list in order until we process the passed event */
 642static void o2hb_run_event_list(struct o2hb_node_event *queued_event)
 643{
 644        int empty;
 645        struct o2hb_callback *hbcall;
 646        struct o2hb_node_event *event;
 647
 648        spin_lock(&o2hb_live_lock);
 649        empty = list_empty(&queued_event->hn_item);
 650        spin_unlock(&o2hb_live_lock);
 651        if (empty)
 652                return;
 653
 654        /* Holding callback sem assures we don't alter the callback
 655         * lists when doing this, and serializes ourselves with other
 656         * processes wanting callbacks. */
 657        down_write(&o2hb_callback_sem);
 658
 659        spin_lock(&o2hb_live_lock);
 660        while (!list_empty(&o2hb_node_events)
 661               && !list_empty(&queued_event->hn_item)) {
 662                event = list_entry(o2hb_node_events.next,
 663                                   struct o2hb_node_event,
 664                                   hn_item);
 665                list_del_init(&event->hn_item);
 666                spin_unlock(&o2hb_live_lock);
 667
 668                mlog(ML_HEARTBEAT, "Node %s event for %d\n",
 669                     event->hn_event_type == O2HB_NODE_UP_CB ? "UP" : "DOWN",
 670                     event->hn_node_num);
 671
 672                hbcall = hbcall_from_type(event->hn_event_type);
 673
 674                /* We should *never* have gotten on to the list with a
 675                 * bad type... This isn't something that we should try
 676                 * to recover from. */
 677                BUG_ON(IS_ERR(hbcall));
 678
 679                o2hb_fire_callbacks(hbcall, event->hn_node, event->hn_node_num);
 680
 681                spin_lock(&o2hb_live_lock);
 682        }
 683        spin_unlock(&o2hb_live_lock);
 684
 685        up_write(&o2hb_callback_sem);
 686}
 687
 688static void o2hb_queue_node_event(struct o2hb_node_event *event,
 689                                  enum o2hb_callback_type type,
 690                                  struct o2nm_node *node,
 691                                  int node_num)
 692{
 693        assert_spin_locked(&o2hb_live_lock);
 694
 695        BUG_ON((!node) && (type != O2HB_NODE_DOWN_CB));
 696
 697        event->hn_event_type = type;
 698        event->hn_node = node;
 699        event->hn_node_num = node_num;
 700
 701        mlog(ML_HEARTBEAT, "Queue node %s event for node %d\n",
 702             type == O2HB_NODE_UP_CB ? "UP" : "DOWN", node_num);
 703
 704        list_add_tail(&event->hn_item, &o2hb_node_events);
 705}
 706
 707static void o2hb_shutdown_slot(struct o2hb_disk_slot *slot)
 708{
 709        struct o2hb_node_event event =
 710                { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 711        struct o2nm_node *node;
 712
 713        node = o2nm_get_node_by_num(slot->ds_node_num);
 714        if (!node)
 715                return;
 716
 717        spin_lock(&o2hb_live_lock);
 718        if (!list_empty(&slot->ds_live_item)) {
 719                mlog(ML_HEARTBEAT, "Shutdown, node %d leaves region\n",
 720                     slot->ds_node_num);
 721
 722                list_del_init(&slot->ds_live_item);
 723
 724                if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 725                        clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 726
 727                        o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB, node,
 728                                              slot->ds_node_num);
 729                }
 730        }
 731        spin_unlock(&o2hb_live_lock);
 732
 733        o2hb_run_event_list(&event);
 734
 735        o2nm_node_put(node);
 736}
 737
 738static void o2hb_set_quorum_device(struct o2hb_region *reg)
 739{
 740        if (!o2hb_global_heartbeat_active())
 741                return;
 742
 743        /* Prevent race with o2hb_heartbeat_group_drop_item() */
 744        if (kthread_should_stop())
 745                return;
 746
 747        /* Tag region as quorum only after thread reaches steady state */
 748        if (atomic_read(&reg->hr_steady_iterations) != 0)
 749                return;
 750
 751        spin_lock(&o2hb_live_lock);
 752
 753        if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 754                goto unlock;
 755
 756        /*
 757         * A region can be added to the quorum only when it sees all
 758         * live nodes heartbeat on it. In other words, the region has been
 759         * added to all nodes.
 760         */
 761        if (memcmp(reg->hr_live_node_bitmap, o2hb_live_node_bitmap,
 762                   sizeof(o2hb_live_node_bitmap)))
 763                goto unlock;
 764
 765        printk(KERN_NOTICE "o2hb: Region %s (%s) is now a quorum device\n",
 766               config_item_name(&reg->hr_item), reg->hr_dev_name);
 767
 768        set_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
 769
 770        /*
 771         * If global heartbeat active, unpin all regions if the
 772         * region count > CUT_OFF
 773         */
 774        if (o2hb_pop_count(&o2hb_quorum_region_bitmap,
 775                           O2NM_MAX_REGIONS) > O2HB_PIN_CUT_OFF)
 776                o2hb_region_unpin(NULL);
 777unlock:
 778        spin_unlock(&o2hb_live_lock);
 779}
 780
 781static int o2hb_check_slot(struct o2hb_region *reg,
 782                           struct o2hb_disk_slot *slot)
 783{
 784        int changed = 0, gen_changed = 0;
 785        struct o2hb_node_event event =
 786                { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 787        struct o2nm_node *node;
 788        struct o2hb_disk_heartbeat_block *hb_block = reg->hr_tmp_block;
 789        u64 cputime;
 790        unsigned int dead_ms = o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS;
 791        unsigned int slot_dead_ms;
 792        int tmp;
 793
 794        memcpy(hb_block, slot->ds_raw_block, reg->hr_block_bytes);
 795
 796        /*
 797         * If a node is no longer configured but is still in the livemap, we
 798         * may need to clear that bit from the livemap.
 799         */
 800        node = o2nm_get_node_by_num(slot->ds_node_num);
 801        if (!node) {
 802                spin_lock(&o2hb_live_lock);
 803                tmp = test_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 804                spin_unlock(&o2hb_live_lock);
 805                if (!tmp)
 806                        return 0;
 807        }
 808
 809        if (!o2hb_verify_crc(reg, hb_block)) {
 810                /* all paths from here will drop o2hb_live_lock for
 811                 * us. */
 812                spin_lock(&o2hb_live_lock);
 813
 814                /* Don't print an error on the console in this case -
 815                 * a freshly formatted heartbeat area will not have a
 816                 * crc set on it. */
 817                if (list_empty(&slot->ds_live_item))
 818                        goto out;
 819
 820                /* The node is live but pushed out a bad crc. We
 821                 * consider it a transient miss but don't populate any
 822                 * other values as they may be junk. */
 823                mlog(ML_ERROR, "Node %d has written a bad crc to %s\n",
 824                     slot->ds_node_num, reg->hr_dev_name);
 825                o2hb_dump_slot(hb_block);
 826
 827                slot->ds_equal_samples++;
 828                goto fire_callbacks;
 829        }
 830
 831        /* we don't care if these wrap.. the state transitions below
 832         * clear at the right places */
 833        cputime = le64_to_cpu(hb_block->hb_seq);
 834        if (slot->ds_last_time != cputime)
 835                slot->ds_changed_samples++;
 836        else
 837                slot->ds_equal_samples++;
 838        slot->ds_last_time = cputime;
 839
 840        /* The node changed heartbeat generations. We assume this to
 841         * mean it dropped off but came back before we timed out. We
 842         * want to consider it down for the time being but don't want
 843         * to lose any changed_samples state we might build up to
 844         * considering it live again. */
 845        if (slot->ds_last_generation != le64_to_cpu(hb_block->hb_generation)) {
 846                gen_changed = 1;
 847                slot->ds_equal_samples = 0;
 848                mlog(ML_HEARTBEAT, "Node %d changed generation (0x%llx "
 849                     "to 0x%llx)\n", slot->ds_node_num,
 850                     (long long)slot->ds_last_generation,
 851                     (long long)le64_to_cpu(hb_block->hb_generation));
 852        }
 853
 854        slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
 855
 856        mlog(ML_HEARTBEAT, "Slot %d gen 0x%llx cksum 0x%x "
 857             "seq %llu last %llu changed %u equal %u\n",
 858             slot->ds_node_num, (long long)slot->ds_last_generation,
 859             le32_to_cpu(hb_block->hb_cksum),
 860             (unsigned long long)le64_to_cpu(hb_block->hb_seq),
 861             (unsigned long long)slot->ds_last_time, slot->ds_changed_samples,
 862             slot->ds_equal_samples);
 863
 864        spin_lock(&o2hb_live_lock);
 865
 866fire_callbacks:
 867        /* dead nodes only come to life after some number of
 868         * changes at any time during their dead time */
 869        if (list_empty(&slot->ds_live_item) &&
 870            slot->ds_changed_samples >= O2HB_LIVE_THRESHOLD) {
 871                mlog(ML_HEARTBEAT, "Node %d (id 0x%llx) joined my region\n",
 872                     slot->ds_node_num, (long long)slot->ds_last_generation);
 873
 874                set_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 875
 876                /* first on the list generates a callback */
 877                if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 878                        mlog(ML_HEARTBEAT, "o2hb: Add node %d to live nodes "
 879                             "bitmap\n", slot->ds_node_num);
 880                        set_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 881
 882                        o2hb_queue_node_event(&event, O2HB_NODE_UP_CB, node,
 883                                              slot->ds_node_num);
 884
 885                        changed = 1;
 886                }
 887
 888                list_add_tail(&slot->ds_live_item,
 889                              &o2hb_live_slots[slot->ds_node_num]);
 890
 891                slot->ds_equal_samples = 0;
 892
 893                /* We want to be sure that all nodes agree on the
 894                 * number of milliseconds before a node will be
 895                 * considered dead. The self-fencing timeout is
 896                 * computed from this value, and a discrepancy might
 897                 * result in heartbeat calling a node dead when it
 898                 * hasn't self-fenced yet. */
 899                slot_dead_ms = le32_to_cpu(hb_block->hb_dead_ms);
 900                if (slot_dead_ms && slot_dead_ms != dead_ms) {
 901                        /* TODO: Perhaps we can fail the region here. */
 902                        mlog(ML_ERROR, "Node %d on device %s has a dead count "
 903                             "of %u ms, but our count is %u ms.\n"
 904                             "Please double check your configuration values "
 905                             "for 'O2CB_HEARTBEAT_THRESHOLD'\n",
 906                             slot->ds_node_num, reg->hr_dev_name, slot_dead_ms,
 907                             dead_ms);
 908                }
 909                goto out;
 910        }
 911
 912        /* if the list is dead, we're done.. */
 913        if (list_empty(&slot->ds_live_item))
 914                goto out;
 915
 916        /* live nodes only go dead after enough consequtive missed
 917         * samples..  reset the missed counter whenever we see
 918         * activity */
 919        if (slot->ds_equal_samples >= o2hb_dead_threshold || gen_changed) {
 920                mlog(ML_HEARTBEAT, "Node %d left my region\n",
 921                     slot->ds_node_num);
 922
 923                clear_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 924
 925                /* last off the live_slot generates a callback */
 926                list_del_init(&slot->ds_live_item);
 927                if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 928                        mlog(ML_HEARTBEAT, "o2hb: Remove node %d from live "
 929                             "nodes bitmap\n", slot->ds_node_num);
 930                        clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 931
 932                        /* node can be null */
 933                        o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB,
 934                                              node, slot->ds_node_num);
 935
 936                        changed = 1;
 937                }
 938
 939                /* We don't clear this because the node is still
 940                 * actually writing new blocks. */
 941                if (!gen_changed)
 942                        slot->ds_changed_samples = 0;
 943                goto out;
 944        }
 945        if (slot->ds_changed_samples) {
 946                slot->ds_changed_samples = 0;
 947                slot->ds_equal_samples = 0;
 948        }
 949out:
 950        spin_unlock(&o2hb_live_lock);
 951
 952        o2hb_run_event_list(&event);
 953
 954        if (node)
 955                o2nm_node_put(node);
 956        return changed;
 957}
 958
 959/* This could be faster if we just implmented a find_last_bit, but I
 960 * don't think the circumstances warrant it. */
 961static int o2hb_highest_node(unsigned long *nodes,
 962                             int numbits)
 963{
 964        int highest, node;
 965
 966        highest = numbits;
 967        node = -1;
 968        while ((node = find_next_bit(nodes, numbits, node + 1)) != -1) {
 969                if (node >= numbits)
 970                        break;
 971
 972                highest = node;
 973        }
 974
 975        return highest;
 976}
 977
 978static int o2hb_do_disk_heartbeat(struct o2hb_region *reg)
 979{
 980        int i, ret, highest_node;
 981        int membership_change = 0, own_slot_ok = 0;
 982        unsigned long configured_nodes[BITS_TO_LONGS(O2NM_MAX_NODES)];
 983        unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 984        struct o2hb_bio_wait_ctxt write_wc;
 985
 986        ret = o2nm_configured_node_map(configured_nodes,
 987                                       sizeof(configured_nodes));
 988        if (ret) {
 989                mlog_errno(ret);
 990                goto bail;
 991        }
 992
 993        /*
 994         * If a node is not configured but is in the livemap, we still need
 995         * to read the slot so as to be able to remove it from the livemap.
 996         */
 997        o2hb_fill_node_map(live_node_bitmap, sizeof(live_node_bitmap));
 998        i = -1;
 999        while ((i = find_next_bit(live_node_bitmap,
1000                                  O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
1001                set_bit(i, configured_nodes);
1002        }
1003
1004        highest_node = o2hb_highest_node(configured_nodes, O2NM_MAX_NODES);
1005        if (highest_node >= O2NM_MAX_NODES) {
1006                mlog(ML_NOTICE, "o2hb: No configured nodes found!\n");
1007                ret = -EINVAL;
1008                goto bail;
1009        }
1010
1011        /* No sense in reading the slots of nodes that don't exist
1012         * yet. Of course, if the node definitions have holes in them
1013         * then we're reading an empty slot anyway... Consider this
1014         * best-effort. */
1015        ret = o2hb_read_slots(reg, highest_node + 1);
1016        if (ret < 0) {
1017                mlog_errno(ret);
1018                goto bail;
1019        }
1020
1021        /* With an up to date view of the slots, we can check that no
1022         * other node has been improperly configured to heartbeat in
1023         * our slot. */
1024        own_slot_ok = o2hb_check_own_slot(reg);
1025
1026        /* fill in the proper info for our next heartbeat */
1027        o2hb_prepare_block(reg, reg->hr_generation);
1028
1029        ret = o2hb_issue_node_write(reg, &write_wc);
1030        if (ret < 0) {
1031                mlog_errno(ret);
1032                goto bail;
1033        }
1034
1035        i = -1;
1036        while((i = find_next_bit(configured_nodes,
1037                                 O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
1038                membership_change |= o2hb_check_slot(reg, &reg->hr_slots[i]);
1039        }
1040
1041        /*
1042         * We have to be sure we've advertised ourselves on disk
1043         * before we can go to steady state.  This ensures that
1044         * people we find in our steady state have seen us.
1045         */
1046        o2hb_wait_on_io(reg, &write_wc);
1047        if (write_wc.wc_error) {
1048                /* Do not re-arm the write timeout on I/O error - we
1049                 * can't be sure that the new block ever made it to
1050                 * disk */
1051                mlog(ML_ERROR, "Write error %d on device \"%s\"\n",
1052                     write_wc.wc_error, reg->hr_dev_name);
1053                ret = write_wc.wc_error;
1054                goto bail;
1055        }
1056
1057        /* Skip disarming the timeout if own slot has stale/bad data */
1058        if (own_slot_ok) {
1059                o2hb_set_quorum_device(reg);
1060                o2hb_arm_write_timeout(reg);
1061        }
1062
1063bail:
1064        /* let the person who launched us know when things are steady */
1065        if (atomic_read(&reg->hr_steady_iterations) != 0) {
1066                if (!ret && own_slot_ok && !membership_change) {
1067                        if (atomic_dec_and_test(&reg->hr_steady_iterations))
1068                                wake_up(&o2hb_steady_queue);
1069                }
1070        }
1071
1072        if (atomic_read(&reg->hr_steady_iterations) != 0) {
1073                if (atomic_dec_and_test(&reg->hr_unsteady_iterations)) {
1074                        printk(KERN_NOTICE "o2hb: Unable to stabilize "
1075                               "heartbeart on region %s (%s)\n",
1076                               config_item_name(&reg->hr_item),
1077                               reg->hr_dev_name);
1078                        atomic_set(&reg->hr_steady_iterations, 0);
1079                        reg->hr_aborted_start = 1;
1080                        wake_up(&o2hb_steady_queue);
1081                        ret = -EIO;
1082                }
1083        }
1084
1085        return ret;
1086}
1087
1088/* Subtract b from a, storing the result in a. a *must* have a larger
1089 * value than b. */
1090static void o2hb_tv_subtract(struct timeval *a,
1091                             struct timeval *b)
1092{
1093        /* just return 0 when a is after b */
1094        if (a->tv_sec < b->tv_sec ||
1095            (a->tv_sec == b->tv_sec && a->tv_usec < b->tv_usec)) {
1096                a->tv_sec = 0;
1097                a->tv_usec = 0;
1098                return;
1099        }
1100
1101        a->tv_sec -= b->tv_sec;
1102        a->tv_usec -= b->tv_usec;
1103        while ( a->tv_usec < 0 ) {
1104                a->tv_sec--;
1105                a->tv_usec += 1000000;
1106        }
1107}
1108
1109static unsigned int o2hb_elapsed_msecs(struct timeval *start,
1110                                       struct timeval *end)
1111{
1112        struct timeval res = *end;
1113
1114        o2hb_tv_subtract(&res, start);
1115
1116        return res.tv_sec * 1000 + res.tv_usec / 1000;
1117}
1118
1119/*
1120 * we ride the region ref that the region dir holds.  before the region
1121 * dir is removed and drops it ref it will wait to tear down this
1122 * thread.
1123 */
1124static int o2hb_thread(void *data)
1125{
1126        int i, ret;
1127        struct o2hb_region *reg = data;
1128        struct o2hb_bio_wait_ctxt write_wc;
1129        struct timeval before_hb, after_hb;
1130        unsigned int elapsed_msec;
1131
1132        mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n");
1133
1134        set_user_nice(current, -20);
1135
1136        /* Pin node */
1137        o2nm_depend_this_node();
1138
1139        while (!kthread_should_stop() &&
1140               !reg->hr_unclean_stop && !reg->hr_aborted_start) {
1141                /* We track the time spent inside
1142                 * o2hb_do_disk_heartbeat so that we avoid more than
1143                 * hr_timeout_ms between disk writes. On busy systems
1144                 * this should result in a heartbeat which is less
1145                 * likely to time itself out. */
1146                do_gettimeofday(&before_hb);
1147
1148                ret = o2hb_do_disk_heartbeat(reg);
1149
1150                do_gettimeofday(&after_hb);
1151                elapsed_msec = o2hb_elapsed_msecs(&before_hb, &after_hb);
1152
1153                mlog(ML_HEARTBEAT,
1154                     "start = %lu.%lu, end = %lu.%lu, msec = %u\n",
1155                     before_hb.tv_sec, (unsigned long) before_hb.tv_usec,
1156                     after_hb.tv_sec, (unsigned long) after_hb.tv_usec,
1157                     elapsed_msec);
1158
1159                if (!kthread_should_stop() &&
1160                    elapsed_msec < reg->hr_timeout_ms) {
1161                        /* the kthread api has blocked signals for us so no
1162                         * need to record the return value. */
1163                        msleep_interruptible(reg->hr_timeout_ms - elapsed_msec);
1164                }
1165        }
1166
1167        o2hb_disarm_write_timeout(reg);
1168
1169        /* unclean stop is only used in very bad situation */
1170        for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
1171                o2hb_shutdown_slot(&reg->hr_slots[i]);
1172
1173        /* Explicit down notification - avoid forcing the other nodes
1174         * to timeout on this region when we could just as easily
1175         * write a clear generation - thus indicating to them that
1176         * this node has left this region.
1177         */
1178        if (!reg->hr_unclean_stop && !reg->hr_aborted_start) {
1179                o2hb_prepare_block(reg, 0);
1180                ret = o2hb_issue_node_write(reg, &write_wc);
1181                if (ret == 0)
1182                        o2hb_wait_on_io(reg, &write_wc);
1183                else
1184                        mlog_errno(ret);
1185        }
1186
1187        /* Unpin node */
1188        o2nm_undepend_this_node();
1189
1190        mlog(ML_HEARTBEAT|ML_KTHREAD, "o2hb thread exiting\n");
1191
1192        return 0;
1193}
1194
1195#ifdef CONFIG_DEBUG_FS
1196static int o2hb_debug_open(struct inode *inode, struct file *file)
1197{
1198        struct o2hb_debug_buf *db = inode->i_private;
1199        struct o2hb_region *reg;
1200        unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1201        unsigned long lts;
1202        char *buf = NULL;
1203        int i = -1;
1204        int out = 0;
1205
1206        /* max_nodes should be the largest bitmap we pass here */
1207        BUG_ON(sizeof(map) < db->db_size);
1208
1209        buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1210        if (!buf)
1211                goto bail;
1212
1213        switch (db->db_type) {
1214        case O2HB_DB_TYPE_LIVENODES:
1215        case O2HB_DB_TYPE_LIVEREGIONS:
1216        case O2HB_DB_TYPE_QUORUMREGIONS:
1217        case O2HB_DB_TYPE_FAILEDREGIONS:
1218                spin_lock(&o2hb_live_lock);
1219                memcpy(map, db->db_data, db->db_size);
1220                spin_unlock(&o2hb_live_lock);
1221                break;
1222
1223        case O2HB_DB_TYPE_REGION_LIVENODES:
1224                spin_lock(&o2hb_live_lock);
1225                reg = (struct o2hb_region *)db->db_data;
1226                memcpy(map, reg->hr_live_node_bitmap, db->db_size);
1227                spin_unlock(&o2hb_live_lock);
1228                break;
1229
1230        case O2HB_DB_TYPE_REGION_NUMBER:
1231                reg = (struct o2hb_region *)db->db_data;
1232                out += snprintf(buf + out, PAGE_SIZE - out, "%d\n",
1233                                reg->hr_region_num);
1234                goto done;
1235
1236        case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
1237                reg = (struct o2hb_region *)db->db_data;
1238                lts = reg->hr_last_timeout_start;
1239                /* If 0, it has never been set before */
1240                if (lts)
1241                        lts = jiffies_to_msecs(jiffies - lts);
1242                out += snprintf(buf + out, PAGE_SIZE - out, "%lu\n", lts);
1243                goto done;
1244
1245        case O2HB_DB_TYPE_REGION_PINNED:
1246                reg = (struct o2hb_region *)db->db_data;
1247                out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
1248                                !!reg->hr_item_pinned);
1249                goto done;
1250
1251        default:
1252                goto done;
1253        }
1254
1255        while ((i = find_next_bit(map, db->db_len, i + 1)) < db->db_len)
1256                out += snprintf(buf + out, PAGE_SIZE - out, "%d ", i);
1257        out += snprintf(buf + out, PAGE_SIZE - out, "\n");
1258
1259done:
1260        i_size_write(inode, out);
1261
1262        file->private_data = buf;
1263
1264        return 0;
1265bail:
1266        return -ENOMEM;
1267}
1268
1269static int o2hb_debug_release(struct inode *inode, struct file *file)
1270{
1271        kfree(file->private_data);
1272        return 0;
1273}
1274
1275static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1276                                 size_t nbytes, loff_t *ppos)
1277{
1278        return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
1279                                       i_size_read(file->f_mapping->host));
1280}
1281#else
1282static int o2hb_debug_open(struct inode *inode, struct file *file)
1283{
1284        return 0;
1285}
1286static int o2hb_debug_release(struct inode *inode, struct file *file)
1287{
1288        return 0;
1289}
1290static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1291                               size_t nbytes, loff_t *ppos)
1292{
1293        return 0;
1294}
1295#endif  /* CONFIG_DEBUG_FS */
1296
1297static const struct file_operations o2hb_debug_fops = {
1298        .open =         o2hb_debug_open,
1299        .release =      o2hb_debug_release,
1300        .read =         o2hb_debug_read,
1301        .llseek =       generic_file_llseek,
1302};
1303
1304void o2hb_exit(void)
1305{
1306        kfree(o2hb_db_livenodes);
1307        kfree(o2hb_db_liveregions);
1308        kfree(o2hb_db_quorumregions);
1309        kfree(o2hb_db_failedregions);
1310        debugfs_remove(o2hb_debug_failedregions);
1311        debugfs_remove(o2hb_debug_quorumregions);
1312        debugfs_remove(o2hb_debug_liveregions);
1313        debugfs_remove(o2hb_debug_livenodes);
1314        debugfs_remove(o2hb_debug_dir);
1315}
1316
1317static struct dentry *o2hb_debug_create(const char *name, struct dentry *dir,
1318                                        struct o2hb_debug_buf **db, int db_len,
1319                                        int type, int size, int len, void *data)
1320{
1321        *db = kmalloc(db_len, GFP_KERNEL);
1322        if (!*db)
1323                return NULL;
1324
1325        (*db)->db_type = type;
1326        (*db)->db_size = size;
1327        (*db)->db_len = len;
1328        (*db)->db_data = data;
1329
1330        return debugfs_create_file(name, S_IFREG|S_IRUSR, dir, *db,
1331                                   &o2hb_debug_fops);
1332}
1333
1334static int o2hb_debug_init(void)
1335{
1336        int ret = -ENOMEM;
1337
1338        o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
1339        if (!o2hb_debug_dir) {
1340                mlog_errno(ret);
1341                goto bail;
1342        }
1343
1344        o2hb_debug_livenodes = o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1345                                                 o2hb_debug_dir,
1346                                                 &o2hb_db_livenodes,
1347                                                 sizeof(*o2hb_db_livenodes),
1348                                                 O2HB_DB_TYPE_LIVENODES,
1349                                                 sizeof(o2hb_live_node_bitmap),
1350                                                 O2NM_MAX_NODES,
1351                                                 o2hb_live_node_bitmap);
1352        if (!o2hb_debug_livenodes) {
1353                mlog_errno(ret);
1354                goto bail;
1355        }
1356
1357        o2hb_debug_liveregions = o2hb_debug_create(O2HB_DEBUG_LIVEREGIONS,
1358                                                   o2hb_debug_dir,
1359                                                   &o2hb_db_liveregions,
1360                                                   sizeof(*o2hb_db_liveregions),
1361                                                   O2HB_DB_TYPE_LIVEREGIONS,
1362                                                   sizeof(o2hb_live_region_bitmap),
1363                                                   O2NM_MAX_REGIONS,
1364                                                   o2hb_live_region_bitmap);
1365        if (!o2hb_debug_liveregions) {
1366                mlog_errno(ret);
1367                goto bail;
1368        }
1369
1370        o2hb_debug_quorumregions =
1371                        o2hb_debug_create(O2HB_DEBUG_QUORUMREGIONS,
1372                                          o2hb_debug_dir,
1373                                          &o2hb_db_quorumregions,
1374                                          sizeof(*o2hb_db_quorumregions),
1375                                          O2HB_DB_TYPE_QUORUMREGIONS,
1376                                          sizeof(o2hb_quorum_region_bitmap),
1377                                          O2NM_MAX_REGIONS,
1378                                          o2hb_quorum_region_bitmap);
1379        if (!o2hb_debug_quorumregions) {
1380                mlog_errno(ret);
1381                goto bail;
1382        }
1383
1384        o2hb_debug_failedregions =
1385                        o2hb_debug_create(O2HB_DEBUG_FAILEDREGIONS,
1386                                          o2hb_debug_dir,
1387                                          &o2hb_db_failedregions,
1388                                          sizeof(*o2hb_db_failedregions),
1389                                          O2HB_DB_TYPE_FAILEDREGIONS,
1390                                          sizeof(o2hb_failed_region_bitmap),
1391                                          O2NM_MAX_REGIONS,
1392                                          o2hb_failed_region_bitmap);
1393        if (!o2hb_debug_failedregions) {
1394                mlog_errno(ret);
1395                goto bail;
1396        }
1397
1398        ret = 0;
1399bail:
1400        if (ret)
1401                o2hb_exit();
1402
1403        return ret;
1404}
1405
1406int o2hb_init(void)
1407{
1408        int i;
1409
1410        for (i = 0; i < ARRAY_SIZE(o2hb_callbacks); i++)
1411                INIT_LIST_HEAD(&o2hb_callbacks[i].list);
1412
1413        for (i = 0; i < ARRAY_SIZE(o2hb_live_slots); i++)
1414                INIT_LIST_HEAD(&o2hb_live_slots[i]);
1415
1416        INIT_LIST_HEAD(&o2hb_node_events);
1417
1418        memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
1419        memset(o2hb_region_bitmap, 0, sizeof(o2hb_region_bitmap));
1420        memset(o2hb_live_region_bitmap, 0, sizeof(o2hb_live_region_bitmap));
1421        memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
1422        memset(o2hb_failed_region_bitmap, 0, sizeof(o2hb_failed_region_bitmap));
1423
1424        o2hb_dependent_users = 0;
1425
1426        return o2hb_debug_init();
1427}
1428
1429/* if we're already in a callback then we're already serialized by the sem */
1430static void o2hb_fill_node_map_from_callback(unsigned long *map,
1431                                             unsigned bytes)
1432{
1433        BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1434
1435        memcpy(map, &o2hb_live_node_bitmap, bytes);
1436}
1437
1438/*
1439 * get a map of all nodes that are heartbeating in any regions
1440 */
1441void o2hb_fill_node_map(unsigned long *map, unsigned bytes)
1442{
1443        /* callers want to serialize this map and callbacks so that they
1444         * can trust that they don't miss nodes coming to the party */
1445        down_read(&o2hb_callback_sem);
1446        spin_lock(&o2hb_live_lock);
1447        o2hb_fill_node_map_from_callback(map, bytes);
1448        spin_unlock(&o2hb_live_lock);
1449        up_read(&o2hb_callback_sem);
1450}
1451EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
1452
1453/*
1454 * heartbeat configfs bits.  The heartbeat set is a default set under
1455 * the cluster set in nodemanager.c.
1456 */
1457
1458static struct o2hb_region *to_o2hb_region(struct config_item *item)
1459{
1460        return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
1461}
1462
1463/* drop_item only drops its ref after killing the thread, nothing should
1464 * be using the region anymore.  this has to clean up any state that
1465 * attributes might have built up. */
1466static void o2hb_region_release(struct config_item *item)
1467{
1468        int i;
1469        struct page *page;
1470        struct o2hb_region *reg = to_o2hb_region(item);
1471
1472        mlog(ML_HEARTBEAT, "hb region release (%s)\n", reg->hr_dev_name);
1473
1474        if (reg->hr_tmp_block)
1475                kfree(reg->hr_tmp_block);
1476
1477        if (reg->hr_slot_data) {
1478                for (i = 0; i < reg->hr_num_pages; i++) {
1479                        page = reg->hr_slot_data[i];
1480                        if (page)
1481                                __free_page(page);
1482                }
1483                kfree(reg->hr_slot_data);
1484        }
1485
1486        if (reg->hr_bdev)
1487                blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1488
1489        if (reg->hr_slots)
1490                kfree(reg->hr_slots);
1491
1492        kfree(reg->hr_db_regnum);
1493        kfree(reg->hr_db_livenodes);
1494        debugfs_remove(reg->hr_debug_livenodes);
1495        debugfs_remove(reg->hr_debug_regnum);
1496        debugfs_remove(reg->hr_debug_elapsed_time);
1497        debugfs_remove(reg->hr_debug_pinned);
1498        debugfs_remove(reg->hr_debug_dir);
1499
1500        spin_lock(&o2hb_live_lock);
1501        list_del(&reg->hr_all_item);
1502        spin_unlock(&o2hb_live_lock);
1503
1504        kfree(reg);
1505}
1506
1507static int o2hb_read_block_input(struct o2hb_region *reg,
1508                                 const char *page,
1509                                 size_t count,
1510                                 unsigned long *ret_bytes,
1511                                 unsigned int *ret_bits)
1512{
1513        unsigned long bytes;
1514        char *p = (char *)page;
1515
1516        bytes = simple_strtoul(p, &p, 0);
1517        if (!p || (*p && (*p != '\n')))
1518                return -EINVAL;
1519
1520        /* Heartbeat and fs min / max block sizes are the same. */
1521        if (bytes > 4096 || bytes < 512)
1522                return -ERANGE;
1523        if (hweight16(bytes) != 1)
1524                return -EINVAL;
1525
1526        if (ret_bytes)
1527                *ret_bytes = bytes;
1528        if (ret_bits)
1529                *ret_bits = ffs(bytes) - 1;
1530
1531        return 0;
1532}
1533
1534static ssize_t o2hb_region_block_bytes_read(struct o2hb_region *reg,
1535                                            char *page)
1536{
1537        return sprintf(page, "%u\n", reg->hr_block_bytes);
1538}
1539
1540static ssize_t o2hb_region_block_bytes_write(struct o2hb_region *reg,
1541                                             const char *page,
1542                                             size_t count)
1543{
1544        int status;
1545        unsigned long block_bytes;
1546        unsigned int block_bits;
1547
1548        if (reg->hr_bdev)
1549                return -EINVAL;
1550
1551        status = o2hb_read_block_input(reg, page, count,
1552                                       &block_bytes, &block_bits);
1553        if (status)
1554                return status;
1555
1556        reg->hr_block_bytes = (unsigned int)block_bytes;
1557        reg->hr_block_bits = block_bits;
1558
1559        return count;
1560}
1561
1562static ssize_t o2hb_region_start_block_read(struct o2hb_region *reg,
1563                                            char *page)
1564{
1565        return sprintf(page, "%llu\n", reg->hr_start_block);
1566}
1567
1568static ssize_t o2hb_region_start_block_write(struct o2hb_region *reg,
1569                                             const char *page,
1570                                             size_t count)
1571{
1572        unsigned long long tmp;
1573        char *p = (char *)page;
1574
1575        if (reg->hr_bdev)
1576                return -EINVAL;
1577
1578        tmp = simple_strtoull(p, &p, 0);
1579        if (!p || (*p && (*p != '\n')))
1580                return -EINVAL;
1581
1582        reg->hr_start_block = tmp;
1583
1584        return count;
1585}
1586
1587static ssize_t o2hb_region_blocks_read(struct o2hb_region *reg,
1588                                       char *page)
1589{
1590        return sprintf(page, "%d\n", reg->hr_blocks);
1591}
1592
1593static ssize_t o2hb_region_blocks_write(struct o2hb_region *reg,
1594                                        const char *page,
1595                                        size_t count)
1596{
1597        unsigned long tmp;
1598        char *p = (char *)page;
1599
1600        if (reg->hr_bdev)
1601                return -EINVAL;
1602
1603        tmp = simple_strtoul(p, &p, 0);
1604        if (!p || (*p && (*p != '\n')))
1605                return -EINVAL;
1606
1607        if (tmp > O2NM_MAX_NODES || tmp == 0)
1608                return -ERANGE;
1609
1610        reg->hr_blocks = (unsigned int)tmp;
1611
1612        return count;
1613}
1614
1615static ssize_t o2hb_region_dev_read(struct o2hb_region *reg,
1616                                    char *page)
1617{
1618        unsigned int ret = 0;
1619
1620        if (reg->hr_bdev)
1621                ret = sprintf(page, "%s\n", reg->hr_dev_name);
1622
1623        return ret;
1624}
1625
1626static void o2hb_init_region_params(struct o2hb_region *reg)
1627{
1628        reg->hr_slots_per_page = PAGE_CACHE_SIZE >> reg->hr_block_bits;
1629        reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
1630
1631        mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
1632             reg->hr_start_block, reg->hr_blocks);
1633        mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
1634             reg->hr_block_bytes, reg->hr_block_bits);
1635        mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
1636        mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
1637}
1638
1639static int o2hb_map_slot_data(struct o2hb_region *reg)
1640{
1641        int i, j;
1642        unsigned int last_slot;
1643        unsigned int spp = reg->hr_slots_per_page;
1644        struct page *page;
1645        char *raw;
1646        struct o2hb_disk_slot *slot;
1647
1648        reg->hr_tmp_block = kmalloc(reg->hr_block_bytes, GFP_KERNEL);
1649        if (reg->hr_tmp_block == NULL) {
1650                mlog_errno(-ENOMEM);
1651                return -ENOMEM;
1652        }
1653
1654        reg->hr_slots = kcalloc(reg->hr_blocks,
1655                                sizeof(struct o2hb_disk_slot), GFP_KERNEL);
1656        if (reg->hr_slots == NULL) {
1657                mlog_errno(-ENOMEM);
1658                return -ENOMEM;
1659        }
1660
1661        for(i = 0; i < reg->hr_blocks; i++) {
1662                slot = &reg->hr_slots[i];
1663                slot->ds_node_num = i;
1664                INIT_LIST_HEAD(&slot->ds_live_item);
1665                slot->ds_raw_block = NULL;
1666        }
1667
1668        reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
1669        mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
1670                           "at %u blocks per page\n",
1671             reg->hr_num_pages, reg->hr_blocks, spp);
1672
1673        reg->hr_slot_data = kcalloc(reg->hr_num_pages, sizeof(struct page *),
1674                                    GFP_KERNEL);
1675        if (!reg->hr_slot_data) {
1676                mlog_errno(-ENOMEM);
1677                return -ENOMEM;
1678        }
1679
1680        for(i = 0; i < reg->hr_num_pages; i++) {
1681                page = alloc_page(GFP_KERNEL);
1682                if (!page) {
1683                        mlog_errno(-ENOMEM);
1684                        return -ENOMEM;
1685                }
1686
1687                reg->hr_slot_data[i] = page;
1688
1689                last_slot = i * spp;
1690                raw = page_address(page);
1691                for (j = 0;
1692                     (j < spp) && ((j + last_slot) < reg->hr_blocks);
1693                     j++) {
1694                        BUG_ON((j + last_slot) >= reg->hr_blocks);
1695
1696                        slot = &reg->hr_slots[j + last_slot];
1697                        slot->ds_raw_block =
1698                                (struct o2hb_disk_heartbeat_block *) raw;
1699
1700                        raw += reg->hr_block_bytes;
1701                }
1702        }
1703
1704        return 0;
1705}
1706
1707/* Read in all the slots available and populate the tracking
1708 * structures so that we can start with a baseline idea of what's
1709 * there. */
1710static int o2hb_populate_slot_data(struct o2hb_region *reg)
1711{
1712        int ret, i;
1713        struct o2hb_disk_slot *slot;
1714        struct o2hb_disk_heartbeat_block *hb_block;
1715
1716        ret = o2hb_read_slots(reg, reg->hr_blocks);
1717        if (ret) {
1718                mlog_errno(ret);
1719                goto out;
1720        }
1721
1722        /* We only want to get an idea of the values initially in each
1723         * slot, so we do no verification - o2hb_check_slot will
1724         * actually determine if each configured slot is valid and
1725         * whether any values have changed. */
1726        for(i = 0; i < reg->hr_blocks; i++) {
1727                slot = &reg->hr_slots[i];
1728                hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
1729
1730                /* Only fill the values that o2hb_check_slot uses to
1731                 * determine changing slots */
1732                slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
1733                slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
1734        }
1735
1736out:
1737        return ret;
1738}
1739
1740/* this is acting as commit; we set up all of hr_bdev and hr_task or nothing */
1741static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
1742                                     const char *page,
1743                                     size_t count)
1744{
1745        struct task_struct *hb_task;
1746        long fd;
1747        int sectsize;
1748        char *p = (char *)page;
1749        struct file *filp = NULL;
1750        struct inode *inode = NULL;
1751        ssize_t ret = -EINVAL;
1752        int live_threshold;
1753
1754        if (reg->hr_bdev)
1755                goto out;
1756
1757        /* We can't heartbeat without having had our node number
1758         * configured yet. */
1759        if (o2nm_this_node() == O2NM_MAX_NODES)
1760                goto out;
1761
1762        fd = simple_strtol(p, &p, 0);
1763        if (!p || (*p && (*p != '\n')))
1764                goto out;
1765
1766        if (fd < 0 || fd >= INT_MAX)
1767                goto out;
1768
1769        filp = fget(fd);
1770        if (filp == NULL)
1771                goto out;
1772
1773        if (reg->hr_blocks == 0 || reg->hr_start_block == 0 ||
1774            reg->hr_block_bytes == 0)
1775                goto out;
1776
1777        inode = igrab(filp->f_mapping->host);
1778        if (inode == NULL)
1779                goto out;
1780
1781        if (!S_ISBLK(inode->i_mode))
1782                goto out;
1783
1784        reg->hr_bdev = I_BDEV(filp->f_mapping->host);
1785        ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ, NULL);
1786        if (ret) {
1787                reg->hr_bdev = NULL;
1788                goto out;
1789        }
1790        inode = NULL;
1791
1792        bdevname(reg->hr_bdev, reg->hr_dev_name);
1793
1794        sectsize = bdev_logical_block_size(reg->hr_bdev);
1795        if (sectsize != reg->hr_block_bytes) {
1796                mlog(ML_ERROR,
1797                     "blocksize %u incorrect for device, expected %d",
1798                     reg->hr_block_bytes, sectsize);
1799                ret = -EINVAL;
1800                goto out;
1801        }
1802
1803        o2hb_init_region_params(reg);
1804
1805        /* Generation of zero is invalid */
1806        do {
1807                get_random_bytes(&reg->hr_generation,
1808                                 sizeof(reg->hr_generation));
1809        } while (reg->hr_generation == 0);
1810
1811        ret = o2hb_map_slot_data(reg);
1812        if (ret) {
1813                mlog_errno(ret);
1814                goto out;
1815        }
1816
1817        ret = o2hb_populate_slot_data(reg);
1818        if (ret) {
1819                mlog_errno(ret);
1820                goto out;
1821        }
1822
1823        INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
1824
1825        /*
1826         * A node is considered live after it has beat LIVE_THRESHOLD
1827         * times.  We're not steady until we've given them a chance
1828         * _after_ our first read.
1829         * The default threshold is bare minimum so as to limit the delay
1830         * during mounts. For global heartbeat, the threshold doubled for the
1831         * first region.
1832         */
1833        live_threshold = O2HB_LIVE_THRESHOLD;
1834        if (o2hb_global_heartbeat_active()) {
1835                spin_lock(&o2hb_live_lock);
1836                if (o2hb_pop_count(&o2hb_region_bitmap, O2NM_MAX_REGIONS) == 1)
1837                        live_threshold <<= 1;
1838                spin_unlock(&o2hb_live_lock);
1839        }
1840        ++live_threshold;
1841        atomic_set(&reg->hr_steady_iterations, live_threshold);
1842        /* unsteady_iterations is double the steady_iterations */
1843        atomic_set(&reg->hr_unsteady_iterations, (live_threshold << 1));
1844
1845        hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
1846                              reg->hr_item.ci_name);
1847        if (IS_ERR(hb_task)) {
1848                ret = PTR_ERR(hb_task);
1849                mlog_errno(ret);
1850                goto out;
1851        }
1852
1853        spin_lock(&o2hb_live_lock);
1854        reg->hr_task = hb_task;
1855        spin_unlock(&o2hb_live_lock);
1856
1857        ret = wait_event_interruptible(o2hb_steady_queue,
1858                                atomic_read(&reg->hr_steady_iterations) == 0);
1859        if (ret) {
1860                atomic_set(&reg->hr_steady_iterations, 0);
1861                reg->hr_aborted_start = 1;
1862        }
1863
1864        if (reg->hr_aborted_start) {
1865                ret = -EIO;
1866                goto out;
1867        }
1868
1869        /* Ok, we were woken.  Make sure it wasn't by drop_item() */
1870        spin_lock(&o2hb_live_lock);
1871        hb_task = reg->hr_task;
1872        if (o2hb_global_heartbeat_active())
1873                set_bit(reg->hr_region_num, o2hb_live_region_bitmap);
1874        spin_unlock(&o2hb_live_lock);
1875
1876        if (hb_task)
1877                ret = count;
1878        else
1879                ret = -EIO;
1880
1881        if (hb_task && o2hb_global_heartbeat_active())
1882                printk(KERN_NOTICE "o2hb: Heartbeat started on region %s (%s)\n",
1883                       config_item_name(&reg->hr_item), reg->hr_dev_name);
1884
1885out:
1886        if (filp)
1887                fput(filp);
1888        if (inode)
1889                iput(inode);
1890        if (ret < 0) {
1891                if (reg->hr_bdev) {
1892                        blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1893                        reg->hr_bdev = NULL;
1894                }
1895        }
1896        return ret;
1897}
1898
1899static ssize_t o2hb_region_pid_read(struct o2hb_region *reg,
1900                                      char *page)
1901{
1902        pid_t pid = 0;
1903
1904        spin_lock(&o2hb_live_lock);
1905        if (reg->hr_task)
1906                pid = task_pid_nr(reg->hr_task);
1907        spin_unlock(&o2hb_live_lock);
1908
1909        if (!pid)
1910                return 0;
1911
1912        return sprintf(page, "%u\n", pid);
1913}
1914
1915struct o2hb_region_attribute {
1916        struct configfs_attribute attr;
1917        ssize_t (*show)(struct o2hb_region *, char *);
1918        ssize_t (*store)(struct o2hb_region *, const char *, size_t);
1919};
1920
1921static struct o2hb_region_attribute o2hb_region_attr_block_bytes = {
1922        .attr   = { .ca_owner = THIS_MODULE,
1923                    .ca_name = "block_bytes",
1924                    .ca_mode = S_IRUGO | S_IWUSR },
1925        .show   = o2hb_region_block_bytes_read,
1926        .store  = o2hb_region_block_bytes_write,
1927};
1928
1929static struct o2hb_region_attribute o2hb_region_attr_start_block = {
1930        .attr   = { .ca_owner = THIS_MODULE,
1931                    .ca_name = "start_block",
1932                    .ca_mode = S_IRUGO | S_IWUSR },
1933        .show   = o2hb_region_start_block_read,
1934        .store  = o2hb_region_start_block_write,
1935};
1936
1937static struct o2hb_region_attribute o2hb_region_attr_blocks = {
1938        .attr   = { .ca_owner = THIS_MODULE,
1939                    .ca_name = "blocks",
1940                    .ca_mode = S_IRUGO | S_IWUSR },
1941        .show   = o2hb_region_blocks_read,
1942        .store  = o2hb_region_blocks_write,
1943};
1944
1945static struct o2hb_region_attribute o2hb_region_attr_dev = {
1946        .attr   = { .ca_owner = THIS_MODULE,
1947                    .ca_name = "dev",
1948                    .ca_mode = S_IRUGO | S_IWUSR },
1949        .show   = o2hb_region_dev_read,
1950        .store  = o2hb_region_dev_write,
1951};
1952
1953static struct o2hb_region_attribute o2hb_region_attr_pid = {
1954       .attr   = { .ca_owner = THIS_MODULE,
1955                   .ca_name = "pid",
1956                   .ca_mode = S_IRUGO | S_IRUSR },
1957       .show   = o2hb_region_pid_read,
1958};
1959
1960static struct configfs_attribute *o2hb_region_attrs[] = {
1961        &o2hb_region_attr_block_bytes.attr,
1962        &o2hb_region_attr_start_block.attr,
1963        &o2hb_region_attr_blocks.attr,
1964        &o2hb_region_attr_dev.attr,
1965        &o2hb_region_attr_pid.attr,
1966        NULL,
1967};
1968
1969static ssize_t o2hb_region_show(struct config_item *item,
1970                                struct configfs_attribute *attr,
1971                                char *page)
1972{
1973        struct o2hb_region *reg = to_o2hb_region(item);
1974        struct o2hb_region_attribute *o2hb_region_attr =
1975                container_of(attr, struct o2hb_region_attribute, attr);
1976        ssize_t ret = 0;
1977
1978        if (o2hb_region_attr->show)
1979                ret = o2hb_region_attr->show(reg, page);
1980        return ret;
1981}
1982
1983static ssize_t o2hb_region_store(struct config_item *item,
1984                                 struct configfs_attribute *attr,
1985                                 const char *page, size_t count)
1986{
1987        struct o2hb_region *reg = to_o2hb_region(item);
1988        struct o2hb_region_attribute *o2hb_region_attr =
1989                container_of(attr, struct o2hb_region_attribute, attr);
1990        ssize_t ret = -EINVAL;
1991
1992        if (o2hb_region_attr->store)
1993                ret = o2hb_region_attr->store(reg, page, count);
1994        return ret;
1995}
1996
1997static struct configfs_item_operations o2hb_region_item_ops = {
1998        .release                = o2hb_region_release,
1999        .show_attribute         = o2hb_region_show,
2000        .store_attribute        = o2hb_region_store,
2001};
2002
2003static struct config_item_type o2hb_region_type = {
2004        .ct_item_ops    = &o2hb_region_item_ops,
2005        .ct_attrs       = o2hb_region_attrs,
2006        .ct_owner       = THIS_MODULE,
2007};
2008
2009/* heartbeat set */
2010
2011struct o2hb_heartbeat_group {
2012        struct config_group hs_group;
2013        /* some stuff? */
2014};
2015
2016static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
2017{
2018        return group ?
2019                container_of(group, struct o2hb_heartbeat_group, hs_group)
2020                : NULL;
2021}
2022
2023static int o2hb_debug_region_init(struct o2hb_region *reg, struct dentry *dir)
2024{
2025        int ret = -ENOMEM;
2026
2027        reg->hr_debug_dir =
2028                debugfs_create_dir(config_item_name(&reg->hr_item), dir);
2029        if (!reg->hr_debug_dir) {
2030                mlog_errno(ret);
2031                goto bail;
2032        }
2033
2034        reg->hr_debug_livenodes =
2035                        o2hb_debug_create(O2HB_DEBUG_LIVENODES,
2036                                          reg->hr_debug_dir,
2037                                          &(reg->hr_db_livenodes),
2038                                          sizeof(*(reg->hr_db_livenodes)),
2039                                          O2HB_DB_TYPE_REGION_LIVENODES,
2040                                          sizeof(reg->hr_live_node_bitmap),
2041                                          O2NM_MAX_NODES, reg);
2042        if (!reg->hr_debug_livenodes) {
2043                mlog_errno(ret);
2044                goto bail;
2045        }
2046
2047        reg->hr_debug_regnum =
2048                        o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER,
2049                                          reg->hr_debug_dir,
2050                                          &(reg->hr_db_regnum),
2051                                          sizeof(*(reg->hr_db_regnum)),
2052                                          O2HB_DB_TYPE_REGION_NUMBER,
2053                                          0, O2NM_MAX_NODES, reg);
2054        if (!reg->hr_debug_regnum) {
2055                mlog_errno(ret);
2056                goto bail;
2057        }
2058
2059        reg->hr_debug_elapsed_time =
2060                        o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME,
2061                                          reg->hr_debug_dir,
2062                                          &(reg->hr_db_elapsed_time),
2063                                          sizeof(*(reg->hr_db_elapsed_time)),
2064                                          O2HB_DB_TYPE_REGION_ELAPSED_TIME,
2065                                          0, 0, reg);
2066        if (!reg->hr_debug_elapsed_time) {
2067                mlog_errno(ret);
2068                goto bail;
2069        }
2070
2071        reg->hr_debug_pinned =
2072                        o2hb_debug_create(O2HB_DEBUG_REGION_PINNED,
2073                                          reg->hr_debug_dir,
2074                                          &(reg->hr_db_pinned),
2075                                          sizeof(*(reg->hr_db_pinned)),
2076                                          O2HB_DB_TYPE_REGION_PINNED,
2077                                          0, 0, reg);
2078        if (!reg->hr_debug_pinned) {
2079                mlog_errno(ret);
2080                goto bail;
2081        }
2082
2083        ret = 0;
2084bail:
2085        return ret;
2086}
2087
2088static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
2089                                                          const char *name)
2090{
2091        struct o2hb_region *reg = NULL;
2092        int ret;
2093
2094        reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
2095        if (reg == NULL)
2096                return ERR_PTR(-ENOMEM);
2097
2098        if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
2099                ret = -ENAMETOOLONG;
2100                goto free;
2101        }
2102
2103        spin_lock(&o2hb_live_lock);
2104        reg->hr_region_num = 0;
2105        if (o2hb_global_heartbeat_active()) {
2106                reg->hr_region_num = find_first_zero_bit(o2hb_region_bitmap,
2107                                                         O2NM_MAX_REGIONS);
2108                if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
2109                        spin_unlock(&o2hb_live_lock);
2110                        ret = -EFBIG;
2111                        goto free;
2112                }
2113                set_bit(reg->hr_region_num, o2hb_region_bitmap);
2114        }
2115        list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
2116        spin_unlock(&o2hb_live_lock);
2117
2118        config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
2119
2120        ret = o2hb_debug_region_init(reg, o2hb_debug_dir);
2121        if (ret) {
2122                config_item_put(&reg->hr_item);
2123                goto free;
2124        }
2125
2126        return &reg->hr_item;
2127free:
2128        kfree(reg);
2129        return ERR_PTR(ret);
2130}
2131
2132static void o2hb_heartbeat_group_drop_item(struct config_group *group,
2133                                           struct config_item *item)
2134{
2135        struct task_struct *hb_task;
2136        struct o2hb_region *reg = to_o2hb_region(item);
2137        int quorum_region = 0;
2138
2139        /* stop the thread when the user removes the region dir */
2140        spin_lock(&o2hb_live_lock);
2141        hb_task = reg->hr_task;
2142        reg->hr_task = NULL;
2143        reg->hr_item_dropped = 1;
2144        spin_unlock(&o2hb_live_lock);
2145
2146        if (hb_task)
2147                kthread_stop(hb_task);
2148
2149        if (o2hb_global_heartbeat_active()) {
2150                spin_lock(&o2hb_live_lock);
2151                clear_bit(reg->hr_region_num, o2hb_region_bitmap);
2152                clear_bit(reg->hr_region_num, o2hb_live_region_bitmap);
2153                if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
2154                        quorum_region = 1;
2155                clear_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
2156                spin_unlock(&o2hb_live_lock);
2157                printk(KERN_NOTICE "o2hb: Heartbeat %s on region %s (%s)\n",
2158                       ((atomic_read(&reg->hr_steady_iterations) == 0) ?
2159                        "stopped" : "start aborted"), config_item_name(item),
2160                       reg->hr_dev_name);
2161        }
2162
2163        /*
2164         * If we're racing a dev_write(), we need to wake them.  They will
2165         * check reg->hr_task
2166         */
2167        if (atomic_read(&reg->hr_steady_iterations) != 0) {
2168                reg->hr_aborted_start = 1;
2169                atomic_set(&reg->hr_steady_iterations, 0);
2170                wake_up(&o2hb_steady_queue);
2171        }
2172
2173        config_item_put(item);
2174
2175        if (!o2hb_global_heartbeat_active() || !quorum_region)
2176                return;
2177
2178        /*
2179         * If global heartbeat active and there are dependent users,
2180         * pin all regions if quorum region count <= CUT_OFF
2181         */
2182        spin_lock(&o2hb_live_lock);
2183
2184        if (!o2hb_dependent_users)
2185                goto unlock;
2186
2187        if (o2hb_pop_count(&o2hb_quorum_region_bitmap,
2188                           O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2189                o2hb_region_pin(NULL);
2190
2191unlock:
2192        spin_unlock(&o2hb_live_lock);
2193}
2194
2195struct o2hb_heartbeat_group_attribute {
2196        struct configfs_attribute attr;
2197        ssize_t (*show)(struct o2hb_heartbeat_group *, char *);
2198        ssize_t (*store)(struct o2hb_heartbeat_group *, const char *, size_t);
2199};
2200
2201static ssize_t o2hb_heartbeat_group_show(struct config_item *item,
2202                                         struct configfs_attribute *attr,
2203                                         char *page)
2204{
2205        struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
2206        struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
2207                container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
2208        ssize_t ret = 0;
2209
2210        if (o2hb_heartbeat_group_attr->show)
2211                ret = o2hb_heartbeat_group_attr->show(reg, page);
2212        return ret;
2213}
2214
2215static ssize_t o2hb_heartbeat_group_store(struct config_item *item,
2216                                          struct configfs_attribute *attr,
2217                                          const char *page, size_t count)
2218{
2219        struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
2220        struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
2221                container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
2222        ssize_t ret = -EINVAL;
2223
2224        if (o2hb_heartbeat_group_attr->store)
2225                ret = o2hb_heartbeat_group_attr->store(reg, page, count);
2226        return ret;
2227}
2228
2229static ssize_t o2hb_heartbeat_group_threshold_show(struct o2hb_heartbeat_group *group,
2230                                                     char *page)
2231{
2232        return sprintf(page, "%u\n", o2hb_dead_threshold);
2233}
2234
2235static ssize_t o2hb_heartbeat_group_threshold_store(struct o2hb_heartbeat_group *group,
2236                                                    const char *page,
2237                                                    size_t count)
2238{
2239        unsigned long tmp;
2240        char *p = (char *)page;
2241
2242        tmp = simple_strtoul(p, &p, 10);
2243        if (!p || (*p && (*p != '\n')))
2244                return -EINVAL;
2245
2246        /* this will validate ranges for us. */
2247        o2hb_dead_threshold_set((unsigned int) tmp);
2248
2249        return count;
2250}
2251
2252static
2253ssize_t o2hb_heartbeat_group_mode_show(struct o2hb_heartbeat_group *group,
2254                                       char *page)
2255{
2256        return sprintf(page, "%s\n",
2257                       o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
2258}
2259
2260static
2261ssize_t o2hb_heartbeat_group_mode_store(struct o2hb_heartbeat_group *group,
2262                                        const char *page, size_t count)
2263{
2264        unsigned int i;
2265        int ret;
2266        size_t len;
2267
2268        len = (page[count - 1] == '\n') ? count - 1 : count;
2269        if (!len)
2270                return -EINVAL;
2271
2272        for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
2273                if (strnicmp(page, o2hb_heartbeat_mode_desc[i], len))
2274                        continue;
2275
2276                ret = o2hb_global_hearbeat_mode_set(i);
2277                if (!ret)
2278                        printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
2279                               o2hb_heartbeat_mode_desc[i]);
2280                return count;
2281        }
2282
2283        return -EINVAL;
2284
2285}
2286
2287static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_threshold = {
2288        .attr   = { .ca_owner = THIS_MODULE,
2289                    .ca_name = "dead_threshold",
2290                    .ca_mode = S_IRUGO | S_IWUSR },
2291        .show   = o2hb_heartbeat_group_threshold_show,
2292        .store  = o2hb_heartbeat_group_threshold_store,
2293};
2294
2295static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_mode = {
2296        .attr   = { .ca_owner = THIS_MODULE,
2297                .ca_name = "mode",
2298                .ca_mode = S_IRUGO | S_IWUSR },
2299        .show   = o2hb_heartbeat_group_mode_show,
2300        .store  = o2hb_heartbeat_group_mode_store,
2301};
2302
2303static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
2304        &o2hb_heartbeat_group_attr_threshold.attr,
2305        &o2hb_heartbeat_group_attr_mode.attr,
2306        NULL,
2307};
2308
2309static struct configfs_item_operations o2hb_hearbeat_group_item_ops = {
2310        .show_attribute         = o2hb_heartbeat_group_show,
2311        .store_attribute        = o2hb_heartbeat_group_store,
2312};
2313
2314static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
2315        .make_item      = o2hb_heartbeat_group_make_item,
2316        .drop_item      = o2hb_heartbeat_group_drop_item,
2317};
2318
2319static struct config_item_type o2hb_heartbeat_group_type = {
2320        .ct_group_ops   = &o2hb_heartbeat_group_group_ops,
2321        .ct_item_ops    = &o2hb_hearbeat_group_item_ops,
2322        .ct_attrs       = o2hb_heartbeat_group_attrs,
2323        .ct_owner       = THIS_MODULE,
2324};
2325
2326/* this is just here to avoid touching group in heartbeat.h which the
2327 * entire damn world #includes */
2328struct config_group *o2hb_alloc_hb_set(void)
2329{
2330        struct o2hb_heartbeat_group *hs = NULL;
2331        struct config_group *ret = NULL;
2332
2333        hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
2334        if (hs == NULL)
2335                goto out;
2336
2337        config_group_init_type_name(&hs->hs_group, "heartbeat",
2338                                    &o2hb_heartbeat_group_type);
2339
2340        ret = &hs->hs_group;
2341out:
2342        if (ret == NULL)
2343                kfree(hs);
2344        return ret;
2345}
2346
2347void o2hb_free_hb_set(struct config_group *group)
2348{
2349        struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
2350        kfree(hs);
2351}
2352
2353/* hb callback registration and issuing */
2354
2355static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
2356{
2357        if (type == O2HB_NUM_CB)
2358                return ERR_PTR(-EINVAL);
2359
2360        return &o2hb_callbacks[type];
2361}
2362
2363void o2hb_setup_callback(struct o2hb_callback_func *hc,
2364                         enum o2hb_callback_type type,
2365                         o2hb_cb_func *func,
2366                         void *data,
2367                         int priority)
2368{
2369        INIT_LIST_HEAD(&hc->hc_item);
2370        hc->hc_func = func;
2371        hc->hc_data = data;
2372        hc->hc_priority = priority;
2373        hc->hc_type = type;
2374        hc->hc_magic = O2HB_CB_MAGIC;
2375}
2376EXPORT_SYMBOL_GPL(o2hb_setup_callback);
2377
2378/*
2379 * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2380 * In global heartbeat mode, region_uuid passed is NULL.
2381 *
2382 * In local, we only pin the matching region. In global we pin all the active
2383 * regions.
2384 */
2385static int o2hb_region_pin(const char *region_uuid)
2386{
2387        int ret = 0, found = 0;
2388        struct o2hb_region *reg;
2389        char *uuid;
2390
2391        assert_spin_locked(&o2hb_live_lock);
2392
2393        list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2394                uuid = config_item_name(&reg->hr_item);
2395
2396                /* local heartbeat */
2397                if (region_uuid) {
2398                        if (strcmp(region_uuid, uuid))
2399                                continue;
2400                        found = 1;
2401                }
2402
2403                if (reg->hr_item_pinned || reg->hr_item_dropped)
2404                        goto skip_pin;
2405
2406                /* Ignore ENOENT only for local hb (userdlm domain) */
2407                ret = o2nm_depend_item(&reg->hr_item);
2408                if (!ret) {
2409                        mlog(ML_CLUSTER, "Pin region %s\n", uuid);
2410                        reg->hr_item_pinned = 1;
2411                } else {
2412                        if (ret == -ENOENT && found)
2413                                ret = 0;
2414                        else {
2415                                mlog(ML_ERROR, "Pin region %s fails with %d\n",
2416                                     uuid, ret);
2417                                break;
2418                        }
2419                }
2420skip_pin:
2421                if (found)
2422                        break;
2423        }
2424
2425        return ret;
2426}
2427
2428/*
2429 * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2430 * In global heartbeat mode, region_uuid passed is NULL.
2431 *
2432 * In local, we only unpin the matching region. In global we unpin all the
2433 * active regions.
2434 */
2435static void o2hb_region_unpin(const char *region_uuid)
2436{
2437        struct o2hb_region *reg;
2438        char *uuid;
2439        int found = 0;
2440
2441        assert_spin_locked(&o2hb_live_lock);
2442
2443        list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2444                uuid = config_item_name(&reg->hr_item);
2445                if (region_uuid) {
2446                        if (strcmp(region_uuid, uuid))
2447                                continue;
2448                        found = 1;
2449                }
2450
2451                if (reg->hr_item_pinned) {
2452                        mlog(ML_CLUSTER, "Unpin region %s\n", uuid);
2453                        o2nm_undepend_item(&reg->hr_item);
2454                        reg->hr_item_pinned = 0;
2455                }
2456                if (found)
2457                        break;
2458        }
2459}
2460
2461static int o2hb_region_inc_user(const char *region_uuid)
2462{
2463        int ret = 0;
2464
2465        spin_lock(&o2hb_live_lock);
2466
2467        /* local heartbeat */
2468        if (!o2hb_global_heartbeat_active()) {
2469            ret = o2hb_region_pin(region_uuid);
2470            goto unlock;
2471        }
2472
2473        /*
2474         * if global heartbeat active and this is the first dependent user,
2475         * pin all regions if quorum region count <= CUT_OFF
2476         */
2477        o2hb_dependent_users++;
2478        if (o2hb_dependent_users > 1)
2479                goto unlock;
2480
2481        if (o2hb_pop_count(&o2hb_quorum_region_bitmap,
2482                           O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2483                ret = o2hb_region_pin(NULL);
2484
2485unlock:
2486        spin_unlock(&o2hb_live_lock);
2487        return ret;
2488}
2489
2490void o2hb_region_dec_user(const char *region_uuid)
2491{
2492        spin_lock(&o2hb_live_lock);
2493
2494        /* local heartbeat */
2495        if (!o2hb_global_heartbeat_active()) {
2496            o2hb_region_unpin(region_uuid);
2497            goto unlock;
2498        }
2499
2500        /*
2501         * if global heartbeat active and there are no dependent users,
2502         * unpin all quorum regions
2503         */
2504        o2hb_dependent_users--;
2505        if (!o2hb_dependent_users)
2506                o2hb_region_unpin(NULL);
2507
2508unlock:
2509        spin_unlock(&o2hb_live_lock);
2510}
2511
2512int o2hb_register_callback(const char *region_uuid,
2513                           struct o2hb_callback_func *hc)
2514{
2515        struct o2hb_callback_func *tmp;
2516        struct list_head *iter;
2517        struct o2hb_callback *hbcall;
2518        int ret;
2519
2520        BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2521        BUG_ON(!list_empty(&hc->hc_item));
2522
2523        hbcall = hbcall_from_type(hc->hc_type);
2524        if (IS_ERR(hbcall)) {
2525                ret = PTR_ERR(hbcall);
2526                goto out;
2527        }
2528
2529        if (region_uuid) {
2530                ret = o2hb_region_inc_user(region_uuid);
2531                if (ret) {
2532                        mlog_errno(ret);
2533                        goto out;
2534                }
2535        }
2536
2537        down_write(&o2hb_callback_sem);
2538
2539        list_for_each(iter, &hbcall->list) {
2540                tmp = list_entry(iter, struct o2hb_callback_func, hc_item);
2541                if (hc->hc_priority < tmp->hc_priority) {
2542                        list_add_tail(&hc->hc_item, iter);
2543                        break;
2544                }
2545        }
2546        if (list_empty(&hc->hc_item))
2547                list_add_tail(&hc->hc_item, &hbcall->list);
2548
2549        up_write(&o2hb_callback_sem);
2550        ret = 0;
2551out:
2552        mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
2553             ret, __builtin_return_address(0), hc);
2554        return ret;
2555}
2556EXPORT_SYMBOL_GPL(o2hb_register_callback);
2557
2558void o2hb_unregister_callback(const char *region_uuid,
2559                              struct o2hb_callback_func *hc)
2560{
2561        BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2562
2563        mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
2564             __builtin_return_address(0), hc);
2565
2566        /* XXX Can this happen _with_ a region reference? */
2567        if (list_empty(&hc->hc_item))
2568                return;
2569
2570        if (region_uuid)
2571                o2hb_region_dec_user(region_uuid);
2572
2573        down_write(&o2hb_callback_sem);
2574
2575        list_del_init(&hc->hc_item);
2576
2577        up_write(&o2hb_callback_sem);
2578}
2579EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
2580
2581int o2hb_check_node_heartbeating(u8 node_num)
2582{
2583        unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2584
2585        o2hb_fill_node_map(testing_map, sizeof(testing_map));
2586        if (!test_bit(node_num, testing_map)) {
2587                mlog(ML_HEARTBEAT,
2588                     "node (%u) does not have heartbeating enabled.\n",
2589                     node_num);
2590                return 0;
2591        }
2592
2593        return 1;
2594}
2595EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating);
2596
2597int o2hb_check_node_heartbeating_from_callback(u8 node_num)
2598{
2599        unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2600
2601        o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2602        if (!test_bit(node_num, testing_map)) {
2603                mlog(ML_HEARTBEAT,
2604                     "node (%u) does not have heartbeating enabled.\n",
2605                     node_num);
2606                return 0;
2607        }
2608
2609        return 1;
2610}
2611EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_from_callback);
2612
2613/* Makes sure our local node is configured with a node number, and is
2614 * heartbeating. */
2615int o2hb_check_local_node_heartbeating(void)
2616{
2617        u8 node_num;
2618
2619        /* if this node was set then we have networking */
2620        node_num = o2nm_this_node();
2621        if (node_num == O2NM_MAX_NODES) {
2622                mlog(ML_HEARTBEAT, "this node has not been configured.\n");
2623                return 0;
2624        }
2625
2626        return o2hb_check_node_heartbeating(node_num);
2627}
2628EXPORT_SYMBOL_GPL(o2hb_check_local_node_heartbeating);
2629
2630/*
2631 * this is just a hack until we get the plumbing which flips file systems
2632 * read only and drops the hb ref instead of killing the node dead.
2633 */
2634void o2hb_stop_all_regions(void)
2635{
2636        struct o2hb_region *reg;
2637
2638        mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");
2639
2640        spin_lock(&o2hb_live_lock);
2641
2642        list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
2643                reg->hr_unclean_stop = 1;
2644
2645        spin_unlock(&o2hb_live_lock);
2646}
2647EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
2648
2649int o2hb_get_all_regions(char *region_uuids, u8 max_regions)
2650{
2651        struct o2hb_region *reg;
2652        int numregs = 0;
2653        char *p;
2654
2655        spin_lock(&o2hb_live_lock);
2656
2657        p = region_uuids;
2658        list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2659                mlog(0, "Region: %s\n", config_item_name(&reg->hr_item));
2660                if (numregs < max_regions) {
2661                        memcpy(p, config_item_name(&reg->hr_item),
2662                               O2HB_MAX_REGION_NAME_LEN);
2663                        p += O2HB_MAX_REGION_NAME_LEN;
2664                }
2665                numregs++;
2666        }
2667
2668        spin_unlock(&o2hb_live_lock);
2669
2670        return numregs;
2671}
2672EXPORT_SYMBOL_GPL(o2hb_get_all_regions);
2673
2674int o2hb_global_heartbeat_active(void)
2675{
2676        return (o2hb_heartbeat_mode == O2HB_HEARTBEAT_GLOBAL);
2677}
2678EXPORT_SYMBOL(o2hb_global_heartbeat_active);
2679