fs/ocfs2/cluster/heartbeat.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * Copyright (C) 2004, 2005 Oracle.  All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public
  17  * License along with this program; if not, write to the
  18  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19  * Boston, MA 021110-1307, USA.
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/sched.h>
  24 #include <linux/jiffies.h>
  25 #include <linux/module.h>
  26 #include <linux/fs.h>
  27 #include <linux/bio.h>
  28 #include <linux/blkdev.h>
  29 #include <linux/delay.h>
  30 #include <linux/file.h>
  31 #include <linux/kthread.h>
  32 #include <linux/configfs.h>
  33 #include <linux/random.h>
  34 #include <linux/crc32.h>
  35 #include <linux/time.h>
  36 #include <linux/debugfs.h>
  37 #include <linux/slab.h>
  38 #include <linux/bitmap.h>
  39 #include <linux/ktime.h>
  40 #include "heartbeat.h"
  41 #include "tcp.h"
  42 #include "nodemanager.h"
  43 #include "quorum.h"
  44
  45 #include "masklog.h"
  46
  47
  48 /*
  49  * The first heartbeat pass had one global thread that would serialize all hb
  50  * callback calls.  This global serializing sem should only be removed once
  51  * we've made sure that all callees can deal with being called concurrently
  52  * from multiple hb region threads.
  53  */
  54 static DECLARE_RWSEM(o2hb_callback_sem);
  55
  56 /*
  57  * multiple hb threads are watching multiple regions.  A node is live
  58  * whenever any of the threads sees activity from the node in its region.
  59  */
  60 static DEFINE_SPINLOCK(o2hb_live_lock);
  61 static struct list_head o2hb_live_slots[O2NM_MAX_NODES];
  62 static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
  63 static LIST_HEAD(o2hb_node_events);
  64 static DECLARE_WAIT_QUEUE_HEAD(o2hb_steady_queue);
  65
  66 /*
  67  * In global heartbeat, we maintain a series of region bitmaps.
  68  *      - o2hb_region_bitmap allows us to limit the region number to max region.
  69  *      - o2hb_live_region_bitmap tracks live regions (seen steady iterations).
  70  *      - o2hb_quorum_region_bitmap tracks live regions that have seen all nodes
  71  *              heartbeat on it.
  72  *      - o2hb_failed_region_bitmap tracks the regions that have seen io timeouts.
  73  */
  74 static unsigned long o2hb_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  75 static unsigned long o2hb_live_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  76 static unsigned long o2hb_quorum_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  77 static unsigned long o2hb_failed_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  78
  79 #define O2HB_DB_TYPE_LIVENODES          0
  80 #define O2HB_DB_TYPE_LIVEREGIONS        1
  81 #define O2HB_DB_TYPE_QUORUMREGIONS      2
  82 #define O2HB_DB_TYPE_FAILEDREGIONS      3
  83 #define O2HB_DB_TYPE_REGION_LIVENODES   4
  84 #define O2HB_DB_TYPE_REGION_NUMBER      5
  85 #define O2HB_DB_TYPE_REGION_ELAPSED_TIME        6
  86 #define O2HB_DB_TYPE_REGION_PINNED      7
  87 struct o2hb_debug_buf {
  88         int db_type;
  89         int db_size;
  90         int db_len;
  91         void *db_data;
  92 };
  93
  94 static struct o2hb_debug_buf *o2hb_db_livenodes;
  95 static struct o2hb_debug_buf *o2hb_db_liveregions;
  96 static struct o2hb_debug_buf *o2hb_db_quorumregions;
  97 static struct o2hb_debug_buf *o2hb_db_failedregions;
  98
  99 #define O2HB_DEBUG_DIR                  "o2hb"
 100 #define O2HB_DEBUG_LIVENODES            "livenodes"
 101 #define O2HB_DEBUG_LIVEREGIONS          "live_regions"
 102 #define O2HB_DEBUG_QUORUMREGIONS        "quorum_regions"
 103 #define O2HB_DEBUG_FAILEDREGIONS        "failed_regions"
 104 #define O2HB_DEBUG_REGION_NUMBER        "num"
 105 #define O2HB_DEBUG_REGION_ELAPSED_TIME  "elapsed_time_in_ms"
 106 #define O2HB_DEBUG_REGION_PINNED        "pinned"
 107
 108 static struct dentry *o2hb_debug_dir;
 109 static struct dentry *o2hb_debug_livenodes;
 110 static struct dentry *o2hb_debug_liveregions;
 111 static struct dentry *o2hb_debug_quorumregions;
 112 static struct dentry *o2hb_debug_failedregions;
 113
 114 static LIST_HEAD(o2hb_all_regions);
 115
 116 static struct o2hb_callback {
 117         struct list_head list;
 118 } o2hb_callbacks[O2HB_NUM_CB];
 119
 120 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type);
 121
 122 #define O2HB_DEFAULT_BLOCK_BITS       9
 123
 124 enum o2hb_heartbeat_modes {
 125         O2HB_HEARTBEAT_LOCAL            = 0,
 126         O2HB_HEARTBEAT_GLOBAL,
 127         O2HB_HEARTBEAT_NUM_MODES,
 128 };
 129
 130 char *o2hb_heartbeat_mode_desc[O2HB_HEARTBEAT_NUM_MODES] = {
 131                 "local",        /* O2HB_HEARTBEAT_LOCAL */
 132                 "global",       /* O2HB_HEARTBEAT_GLOBAL */
 133 };
 134
 135 unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
 136 unsigned int o2hb_heartbeat_mode = O2HB_HEARTBEAT_LOCAL;
 137
 138 /*
 139  * o2hb_dependent_users tracks the number of registered callbacks that depend
 140  * on heartbeat. o2net and o2dlm are two entities that register this callback.
 141  * However only o2dlm depends on the heartbeat. It does not want the heartbeat
 142  * to stop while a dlm domain is still active.
 143  */
 144 unsigned int o2hb_dependent_users;
 145
 146 /*
 147  * In global heartbeat mode, all regions are pinned if there are one or more
 148  * dependent users and the quorum region count is <= O2HB_PIN_CUT_OFF. All
 149  * regions are unpinned if the region count exceeds the cut off or the number
 150  * of dependent users falls to zero.
 151  */
 152 #define O2HB_PIN_CUT_OFF                3
 153
 154 /*
 155  * In local heartbeat mode, we assume the dlm domain name to be the same as
 156  * region uuid. This is true for domains created for the file system but not
 157  * necessarily true for userdlm domains. This is a known limitation.
 158  *
 159  * In global heartbeat mode, we pin/unpin all o2hb regions. This solution
 160  * works for both file system and userdlm domains.
 161  */
 162 static int o2hb_region_pin(const char *region_uuid);
 163 static void o2hb_region_unpin(const char *region_uuid);
 164
 165 /* Only sets a new threshold if there are no active regions.
 166  *
 167  * No locking or otherwise interesting code is required for reading
 168  * o2hb_dead_threshold as it can't change once regions are active and
 169  * it's not interesting to anyone until then anyway. */
 170 static void o2hb_dead_threshold_set(unsigned int threshold)
 171 {
 172         if (threshold > O2HB_MIN_DEAD_THRESHOLD) {
 173                 spin_lock(&o2hb_live_lock);
 174                 if (list_empty(&o2hb_all_regions))
 175                         o2hb_dead_threshold = threshold;
 176                 spin_unlock(&o2hb_live_lock);
 177         }
 178 }
 179
 180 static int o2hb_global_heartbeat_mode_set(unsigned int hb_mode)
 181 {
 182         int ret = -1;
 183
 184         if (hb_mode < O2HB_HEARTBEAT_NUM_MODES) {
 185                 spin_lock(&o2hb_live_lock);
 186                 if (list_empty(&o2hb_all_regions)) {
 187                         o2hb_heartbeat_mode = hb_mode;
 188                         ret = 0;
 189                 }
 190                 spin_unlock(&o2hb_live_lock);
 191         }
 192
 193         return ret;
 194 }
 195
 196 struct o2hb_node_event {
 197         struct list_head        hn_item;
 198         enum o2hb_callback_type hn_event_type;
 199         struct o2nm_node        *hn_node;
 200         int                     hn_node_num;
 201 };
 202
 203 struct o2hb_disk_slot {
 204         struct o2hb_disk_heartbeat_block *ds_raw_block;
 205         u8                      ds_node_num;
 206         u64                     ds_last_time;
 207         u64                     ds_last_generation;
 208         u16                     ds_equal_samples;
 209         u16                     ds_changed_samples;
 210         struct list_head        ds_live_item;
 211 };
 212
 213 /* each thread owns a region.. when we're asked to tear down the region
 214  * we ask the thread to stop, who cleans up the region */
 215 struct o2hb_region {
 216         struct config_item      hr_item;
 217
 218         struct list_head        hr_all_item;
 219         unsigned                hr_unclean_stop:1,
 220                                 hr_aborted_start:1,
 221                                 hr_item_pinned:1,
 222                                 hr_item_dropped:1;
 223
 224         /* protected by the hr_callback_sem */
 225         struct task_struct      *hr_task;
 226
 227         unsigned int            hr_blocks;
 228         unsigned long long      hr_start_block;
 229
 230         unsigned int            hr_block_bits;
 231         unsigned int            hr_block_bytes;
 232
 233         unsigned int            hr_slots_per_page;
 234         unsigned int            hr_num_pages;
 235
 236         struct page             **hr_slot_data;
 237         struct block_device     *hr_bdev;
 238         struct o2hb_disk_slot   *hr_slots;
 239
 240         /* live node map of this region */
 241         unsigned long           hr_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 242         unsigned int            hr_region_num;
 243
 244         struct dentry           *hr_debug_dir;
 245         struct dentry           *hr_debug_livenodes;
 246         struct dentry           *hr_debug_regnum;
 247         struct dentry           *hr_debug_elapsed_time;
 248         struct dentry           *hr_debug_pinned;
 249         struct o2hb_debug_buf   *hr_db_livenodes;
 250         struct o2hb_debug_buf   *hr_db_regnum;
 251         struct o2hb_debug_buf   *hr_db_elapsed_time;
 252         struct o2hb_debug_buf   *hr_db_pinned;
 253
 254         /* let the person setting up hb wait for it to return until it
 255          * has reached a 'steady' state.  This will be fixed when we have
 256          * a more complete api that doesn't lead to this sort of fragility. */
 257         atomic_t                hr_steady_iterations;
 258
 259         /* terminate o2hb thread if it does not reach steady state
 260          * (hr_steady_iterations == 0) within hr_unsteady_iterations */
 261         atomic_t                hr_unsteady_iterations;
 262
 263         char                    hr_dev_name[BDEVNAME_SIZE];
 264
 265         unsigned int            hr_timeout_ms;
 266
 267         /* randomized as the region goes up and down so that a node
 268          * recognizes a node going up and down in one iteration */
 269         u64                     hr_generation;
 270
 271         struct delayed_work     hr_write_timeout_work;
 272         unsigned long           hr_last_timeout_start;
 273
 274         /* Used during o2hb_check_slot to hold a copy of the block
 275          * being checked because we temporarily have to zero out the
 276          * crc field. */
 277         struct o2hb_disk_heartbeat_block *hr_tmp_block;
 278 };
 279
 280 struct o2hb_bio_wait_ctxt {
 281         atomic_t          wc_num_reqs;
 282         struct completion wc_io_complete;
 283         int               wc_error;
 284 };
 285
 286 static void o2hb_write_timeout(struct work_struct *work)
 287 {
 288         int failed, quorum;
 289         unsigned long flags;
 290         struct o2hb_region *reg =
 291                 container_of(work, struct o2hb_region,
 292                              hr_write_timeout_work.work);
 293
 294         mlog(ML_ERROR, "Heartbeat write timeout to device %s after %u "
 295              "milliseconds\n", reg->hr_dev_name,
 296              jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
 297
 298         if (o2hb_global_heartbeat_active()) {
 299                 spin_lock_irqsave(&o2hb_live_lock, flags);
 300                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 301                         set_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 302                 failed = bitmap_weight(o2hb_failed_region_bitmap,
 303                                         O2NM_MAX_REGIONS);
 304                 quorum = bitmap_weight(o2hb_quorum_region_bitmap,
 305                                         O2NM_MAX_REGIONS);
 306                 spin_unlock_irqrestore(&o2hb_live_lock, flags);
 307
 308                 mlog(ML_HEARTBEAT, "Number of regions %d, failed regions %d\n",
 309                      quorum, failed);
 310
 311                 /*
 312                  * Fence if the number of failed regions >= half the number
 313                  * of  quorum regions
 314                  */
 315                 if ((failed << 1) < quorum)
 316                         return;
 317         }
 318
 319         o2quo_disk_timeout();
 320 }
 321
 322 static void o2hb_arm_write_timeout(struct o2hb_region *reg)
 323 {
 324         /* Arm writeout only after thread reaches steady state */
 325         if (atomic_read(&reg->hr_steady_iterations) != 0)
 326                 return;
 327
 328         mlog(ML_HEARTBEAT, "Queue write timeout for %u ms\n",
 329              O2HB_MAX_WRITE_TIMEOUT_MS);
 330
 331         if (o2hb_global_heartbeat_active()) {
 332                 spin_lock(&o2hb_live_lock);
 333                 clear_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 334                 spin_unlock(&o2hb_live_lock);
 335         }
 336         cancel_delayed_work(&reg->hr_write_timeout_work);
 337         reg->hr_last_timeout_start = jiffies;
 338         schedule_delayed_work(&reg->hr_write_timeout_work,
 339                               msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
 340 }
 341
 342 static void o2hb_disarm_write_timeout(struct o2hb_region *reg)
 343 {
 344         cancel_delayed_work_sync(&reg->hr_write_timeout_work);
 345 }
 346
 347 static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
 348 {
 349         atomic_set(&wc->wc_num_reqs, 1);
 350         init_completion(&wc->wc_io_complete);
 351         wc->wc_error = 0;
 352 }
 353
 354 /* Used in error paths too */
 355 static inline void o2hb_bio_wait_dec(struct o2hb_bio_wait_ctxt *wc,
 356                                      unsigned int num)
 357 {
 358         /* sadly atomic_sub_and_test() isn't available on all platforms.  The
 359          * good news is that the fast path only completes one at a time */
 360         while(num--) {
 361                 if (atomic_dec_and_test(&wc->wc_num_reqs)) {
 362                         BUG_ON(num > 0);
 363                         complete(&wc->wc_io_complete);
 364                 }
 365         }
 366 }
 367
 368 static void o2hb_wait_on_io(struct o2hb_region *reg,
 369                             struct o2hb_bio_wait_ctxt *wc)
 370 {
 371         o2hb_bio_wait_dec(wc, 1);
 372         wait_for_completion(&wc->wc_io_complete);
 373 }
 374
 375 static void o2hb_bio_end_io(struct bio *bio)
 376 {
 377         struct o2hb_bio_wait_ctxt *wc = bio->bi_private;
 378
 379         if (bio->bi_error) {
 380                 mlog(ML_ERROR, "IO Error %d\n", bio->bi_error);
 381                 wc->wc_error = bio->bi_error;
 382         }
 383
 384         o2hb_bio_wait_dec(wc, 1);
 385         bio_put(bio);
 386 }
 387
 388 /* Setup a Bio to cover I/O against num_slots slots starting at
 389  * start_slot. */
 390 static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
 391                                       struct o2hb_bio_wait_ctxt *wc,
 392                                       unsigned int *current_slot,
 393                                       unsigned int max_slots)
 394 {
 395         int len, current_page;
 396         unsigned int vec_len, vec_start;
 397         unsigned int bits = reg->hr_block_bits;
 398         unsigned int spp = reg->hr_slots_per_page;
 399         unsigned int cs = *current_slot;
 400         struct bio *bio;
 401         struct page *page;
 402
 403         /* Testing has shown this allocation to take long enough under
 404          * GFP_KERNEL that the local node can get fenced. It would be
 405          * nicest if we could pre-allocate these bios and avoid this
 406          * all together. */
 407         bio = bio_alloc(GFP_ATOMIC, 16);
 408         if (!bio) {
 409                 mlog(ML_ERROR, "Could not alloc slots BIO!\n");
 410                 bio = ERR_PTR(-ENOMEM);
 411                 goto bail;
 412         }
 413
 414         /* Must put everything in 512 byte sectors for the bio... */
 415         bio->bi_iter.bi_sector = (reg->hr_start_block + cs) << (bits - 9);
 416         bio->bi_bdev = reg->hr_bdev;
 417         bio->bi_private = wc;
 418         bio->bi_end_io = o2hb_bio_end_io;
 419
 420         vec_start = (cs << bits) % PAGE_CACHE_SIZE;
 421         while(cs < max_slots) {
 422                 current_page = cs / spp;
 423                 page = reg->hr_slot_data[current_page];
 424
 425                 vec_len = min(PAGE_CACHE_SIZE - vec_start,
 426                               (max_slots-cs) * (PAGE_CACHE_SIZE/spp) );
 427
 428                 mlog(ML_HB_BIO, "page %d, vec_len = %u, vec_start = %u\n",
 429                      current_page, vec_len, vec_start);
 430
 431                 len = bio_add_page(bio, page, vec_len, vec_start);
 432                 if (len != vec_len) break;
 433
 434                 cs += vec_len / (PAGE_CACHE_SIZE/spp);
 435                 vec_start = 0;
 436         }
 437
 438 bail:
 439         *current_slot = cs;
 440         return bio;
 441 }
 442
 443 static int o2hb_read_slots(struct o2hb_region *reg,
 444                            unsigned int max_slots)
 445 {
 446         unsigned int current_slot=0;
 447         int status;
 448         struct o2hb_bio_wait_ctxt wc;
 449         struct bio *bio;
 450
 451         o2hb_bio_wait_init(&wc);
 452
 453         while(current_slot < max_slots) {
 454                 bio = o2hb_setup_one_bio(reg, &wc, &current_slot, max_slots);
 455                 if (IS_ERR(bio)) {
 456                         status = PTR_ERR(bio);
 457                         mlog_errno(status);
 458                         goto bail_and_wait;
 459                 }
 460
 461                 atomic_inc(&wc.wc_num_reqs);
 462                 submit_bio(READ, bio);
 463         }
 464
 465         status = 0;
 466
 467 bail_and_wait:
 468         o2hb_wait_on_io(reg, &wc);
 469         if (wc.wc_error && !status)
 470                 status = wc.wc_error;
 471
 472         return status;
 473 }
 474
 475 static int o2hb_issue_node_write(struct o2hb_region *reg,
 476                                  struct o2hb_bio_wait_ctxt *write_wc)
 477 {
 478         int status;
 479         unsigned int slot;
 480         struct bio *bio;
 481
 482         o2hb_bio_wait_init(write_wc);
 483
 484         slot = o2nm_this_node();
 485
 486         bio = o2hb_setup_one_bio(reg, write_wc, &slot, slot+1);
 487         if (IS_ERR(bio)) {
 488                 status = PTR_ERR(bio);
 489                 mlog_errno(status);
 490                 goto bail;
 491         }
 492
 493         atomic_inc(&write_wc->wc_num_reqs);
 494         submit_bio(WRITE_SYNC, bio);
 495
 496         status = 0;
 497 bail:
 498         return status;
 499 }
 500
 501 static u32 o2hb_compute_block_crc_le(struct o2hb_region *reg,
 502                                      struct o2hb_disk_heartbeat_block *hb_block)
 503 {
 504         __le32 old_cksum;
 505         u32 ret;
 506
 507         /* We want to compute the block crc with a 0 value in the
 508          * hb_cksum field. Save it off here and replace after the
 509          * crc. */
 510         old_cksum = hb_block->hb_cksum;
 511         hb_block->hb_cksum = 0;
 512
 513         ret = crc32_le(0, (unsigned char *) hb_block, reg->hr_block_bytes);
 514
 515         hb_block->hb_cksum = old_cksum;
 516
 517         return ret;
 518 }
 519
 520 static void o2hb_dump_slot(struct o2hb_disk_heartbeat_block *hb_block)
 521 {
 522         mlog(ML_ERROR, "Dump slot information: seq = 0x%llx, node = %u, "
 523              "cksum = 0x%x, generation 0x%llx\n",
 524              (long long)le64_to_cpu(hb_block->hb_seq),
 525              hb_block->hb_node, le32_to_cpu(hb_block->hb_cksum),
 526              (long long)le64_to_cpu(hb_block->hb_generation));
 527 }
 528
 529 static int o2hb_verify_crc(struct o2hb_region *reg,
 530                            struct o2hb_disk_heartbeat_block *hb_block)
 531 {
 532         u32 read, computed;
 533
 534         read = le32_to_cpu(hb_block->hb_cksum);
 535         computed = o2hb_compute_block_crc_le(reg, hb_block);
 536
 537         return read == computed;
 538 }
 539
 540 /*
 541  * Compare the slot data with what we wrote in the last iteration.
 542  * If the match fails, print an appropriate error message. This is to
 543  * detect errors like... another node hearting on the same slot,
 544  * flaky device that is losing writes, etc.
 545  * Returns 1 if check succeeds, 0 otherwise.
 546  */
 547 static int o2hb_check_own_slot(struct o2hb_region *reg)
 548 {
 549         struct o2hb_disk_slot *slot;
 550         struct o2hb_disk_heartbeat_block *hb_block;
 551         char *errstr;
 552
 553         slot = &reg->hr_slots[o2nm_this_node()];
 554         /* Don't check on our 1st timestamp */
 555         if (!slot->ds_last_time)
 556                 return 0;
 557
 558         hb_block = slot->ds_raw_block;
 559         if (le64_to_cpu(hb_block->hb_seq) == slot->ds_last_time &&
 560             le64_to_cpu(hb_block->hb_generation) == slot->ds_last_generation &&
 561             hb_block->hb_node == slot->ds_node_num)
 562                 return 1;
 563
 564 #define ERRSTR1         "Another node is heartbeating on device"
 565 #define ERRSTR2         "Heartbeat generation mismatch on device"
 566 #define ERRSTR3         "Heartbeat sequence mismatch on device"
 567
 568         if (hb_block->hb_node != slot->ds_node_num)
 569                 errstr = ERRSTR1;
 570         else if (le64_to_cpu(hb_block->hb_generation) !=
 571                  slot->ds_last_generation)
 572                 errstr = ERRSTR2;
 573         else
 574                 errstr = ERRSTR3;
 575
 576         mlog(ML_ERROR, "%s (%s): expected(%u:0x%llx, 0x%llx), "
 577              "ondisk(%u:0x%llx, 0x%llx)\n", errstr, reg->hr_dev_name,
 578              slot->ds_node_num, (unsigned long long)slot->ds_last_generation,
 579              (unsigned long long)slot->ds_last_time, hb_block->hb_node,
 580              (unsigned long long)le64_to_cpu(hb_block->hb_generation),
 581              (unsigned long long)le64_to_cpu(hb_block->hb_seq));
 582
 583         return 0;
 584 }
 585
 586 static inline void o2hb_prepare_block(struct o2hb_region *reg,
 587                                       u64 generation)
 588 {
 589         int node_num;
 590         u64 cputime;
 591         struct o2hb_disk_slot *slot;
 592         struct o2hb_disk_heartbeat_block *hb_block;
 593
 594         node_num = o2nm_this_node();
 595         slot = &reg->hr_slots[node_num];
 596
 597         hb_block = (struct o2hb_disk_heartbeat_block *)slot->ds_raw_block;
 598         memset(hb_block, 0, reg->hr_block_bytes);
 599         /* TODO: time stuff */
 600         cputime = CURRENT_TIME.tv_sec;
 601         if (!cputime)
 602                 cputime = 1;
 603
 604         hb_block->hb_seq = cpu_to_le64(cputime);
 605         hb_block->hb_node = node_num;
 606         hb_block->hb_generation = cpu_to_le64(generation);
 607         hb_block->hb_dead_ms = cpu_to_le32(o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS);
 608
 609         /* This step must always happen last! */
 610         hb_block->hb_cksum = cpu_to_le32(o2hb_compute_block_crc_le(reg,
 611                                                                    hb_block));
 612
 613         mlog(ML_HB_BIO, "our node generation = 0x%llx, cksum = 0x%x\n",
 614              (long long)generation,
 615              le32_to_cpu(hb_block->hb_cksum));
 616 }
 617
 618 static void o2hb_fire_callbacks(struct o2hb_callback *hbcall,
 619                                 struct o2nm_node *node,
 620                                 int idx)
 621 {
 622         struct o2hb_callback_func *f;
 623
 624         list_for_each_entry(f, &hbcall->list, hc_item) {
 625                 mlog(ML_HEARTBEAT, "calling funcs %p\n", f);
 626                 (f->hc_func)(node, idx, f->hc_data);
 627         }
 628 }
 629
 630 /* Will run the list in order until we process the passed event */
 631 static void o2hb_run_event_list(struct o2hb_node_event *queued_event)
 632 {
 633         struct o2hb_callback *hbcall;
 634         struct o2hb_node_event *event;
 635
 636         /* Holding callback sem assures we don't alter the callback
 637          * lists when doing this, and serializes ourselves with other
 638          * processes wanting callbacks. */
 639         down_write(&o2hb_callback_sem);
 640
 641         spin_lock(&o2hb_live_lock);
 642         while (!list_empty(&o2hb_node_events)
 643                && !list_empty(&queued_event->hn_item)) {
 644                 event = list_entry(o2hb_node_events.next,
 645                                    struct o2hb_node_event,
 646                                    hn_item);
 647                 list_del_init(&event->hn_item);
 648                 spin_unlock(&o2hb_live_lock);
 649
 650                 mlog(ML_HEARTBEAT, "Node %s event for %d\n",
 651                      event->hn_event_type == O2HB_NODE_UP_CB ? "UP" : "DOWN",
 652                      event->hn_node_num);
 653
 654                 hbcall = hbcall_from_type(event->hn_event_type);
 655
 656                 /* We should *never* have gotten on to the list with a
 657                  * bad type... This isn't something that we should try
 658                  * to recover from. */
 659                 BUG_ON(IS_ERR(hbcall));
 660
 661                 o2hb_fire_callbacks(hbcall, event->hn_node, event->hn_node_num);
 662
 663                 spin_lock(&o2hb_live_lock);
 664         }
 665         spin_unlock(&o2hb_live_lock);
 666
 667         up_write(&o2hb_callback_sem);
 668 }
 669
 670 static void o2hb_queue_node_event(struct o2hb_node_event *event,
 671                                   enum o2hb_callback_type type,
 672                                   struct o2nm_node *node,
 673                                   int node_num)
 674 {
 675         assert_spin_locked(&o2hb_live_lock);
 676
 677         BUG_ON((!node) && (type != O2HB_NODE_DOWN_CB));
 678
 679         event->hn_event_type = type;
 680         event->hn_node = node;
 681         event->hn_node_num = node_num;
 682
 683         mlog(ML_HEARTBEAT, "Queue node %s event for node %d\n",
 684              type == O2HB_NODE_UP_CB ? "UP" : "DOWN", node_num);
 685
 686         list_add_tail(&event->hn_item, &o2hb_node_events);
 687 }
 688
 689 static void o2hb_shutdown_slot(struct o2hb_disk_slot *slot)
 690 {
 691         struct o2hb_node_event event =
 692                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 693         struct o2nm_node *node;
 694         int queued = 0;
 695
 696         node = o2nm_get_node_by_num(slot->ds_node_num);
 697         if (!node)
 698                 return;
 699
 700         spin_lock(&o2hb_live_lock);
 701         if (!list_empty(&slot->ds_live_item)) {
 702                 mlog(ML_HEARTBEAT, "Shutdown, node %d leaves region\n",
 703                      slot->ds_node_num);
 704
 705                 list_del_init(&slot->ds_live_item);
 706
 707                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 708                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 709
 710                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB, node,
 711                                               slot->ds_node_num);
 712                         queued = 1;
 713                 }
 714         }
 715         spin_unlock(&o2hb_live_lock);
 716
 717         if (queued)
 718                 o2hb_run_event_list(&event);
 719
 720         o2nm_node_put(node);
 721 }
 722
 723 static void o2hb_set_quorum_device(struct o2hb_region *reg)
 724 {
 725         if (!o2hb_global_heartbeat_active())
 726                 return;
 727
 728         /* Prevent race with o2hb_heartbeat_group_drop_item() */
 729         if (kthread_should_stop())
 730                 return;
 731
 732         /* Tag region as quorum only after thread reaches steady state */
 733         if (atomic_read(&reg->hr_steady_iterations) != 0)
 734                 return;
 735
 736         spin_lock(&o2hb_live_lock);
 737
 738         if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 739                 goto unlock;
 740
 741         /*
 742          * A region can be added to the quorum only when it sees all
 743          * live nodes heartbeat on it. In other words, the region has been
 744          * added to all nodes.
 745          */
 746         if (memcmp(reg->hr_live_node_bitmap, o2hb_live_node_bitmap,
 747                    sizeof(o2hb_live_node_bitmap)))
 748                 goto unlock;
 749
 750         printk(KERN_NOTICE "o2hb: Region %s (%s) is now a quorum device\n",
 751                config_item_name(&reg->hr_item), reg->hr_dev_name);
 752
 753         set_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
 754
 755         /*
 756          * If global heartbeat active, unpin all regions if the
 757          * region count > CUT_OFF
 758          */
 759         if (bitmap_weight(o2hb_quorum_region_bitmap,
 760                            O2NM_MAX_REGIONS) > O2HB_PIN_CUT_OFF)
 761                 o2hb_region_unpin(NULL);
 762 unlock:
 763         spin_unlock(&o2hb_live_lock);
 764 }
 765
 766 static int o2hb_check_slot(struct o2hb_region *reg,
 767                            struct o2hb_disk_slot *slot)
 768 {
 769         int changed = 0, gen_changed = 0;
 770         struct o2hb_node_event event =
 771                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 772         struct o2nm_node *node;
 773         struct o2hb_disk_heartbeat_block *hb_block = reg->hr_tmp_block;
 774         u64 cputime;
 775         unsigned int dead_ms = o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS;
 776         unsigned int slot_dead_ms;
 777         int tmp;
 778         int queued = 0;
 779
 780         memcpy(hb_block, slot->ds_raw_block, reg->hr_block_bytes);
 781
 782         /*
 783          * If a node is no longer configured but is still in the livemap, we
 784          * may need to clear that bit from the livemap.
 785          */
 786         node = o2nm_get_node_by_num(slot->ds_node_num);
 787         if (!node) {
 788                 spin_lock(&o2hb_live_lock);
 789                 tmp = test_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 790                 spin_unlock(&o2hb_live_lock);
 791                 if (!tmp)
 792                         return 0;
 793         }
 794
 795         if (!o2hb_verify_crc(reg, hb_block)) {
 796                 /* all paths from here will drop o2hb_live_lock for
 797                  * us. */
 798                 spin_lock(&o2hb_live_lock);
 799
 800                 /* Don't print an error on the console in this case -
 801                  * a freshly formatted heartbeat area will not have a
 802                  * crc set on it. */
 803                 if (list_empty(&slot->ds_live_item))
 804                         goto out;
 805
 806                 /* The node is live but pushed out a bad crc. We
 807                  * consider it a transient miss but don't populate any
 808                  * other values as they may be junk. */
 809                 mlog(ML_ERROR, "Node %d has written a bad crc to %s\n",
 810                      slot->ds_node_num, reg->hr_dev_name);
 811                 o2hb_dump_slot(hb_block);
 812
 813                 slot->ds_equal_samples++;
 814                 goto fire_callbacks;
 815         }
 816
 817         /* we don't care if these wrap.. the state transitions below
 818          * clear at the right places */
 819         cputime = le64_to_cpu(hb_block->hb_seq);
 820         if (slot->ds_last_time != cputime)
 821                 slot->ds_changed_samples++;
 822         else
 823                 slot->ds_equal_samples++;
 824         slot->ds_last_time = cputime;
 825
 826         /* The node changed heartbeat generations. We assume this to
 827          * mean it dropped off but came back before we timed out. We
 828          * want to consider it down for the time being but don't want
 829          * to lose any changed_samples state we might build up to
 830          * considering it live again. */
 831         if (slot->ds_last_generation != le64_to_cpu(hb_block->hb_generation)) {
 832                 gen_changed = 1;
 833                 slot->ds_equal_samples = 0;
 834                 mlog(ML_HEARTBEAT, "Node %d changed generation (0x%llx "
 835                      "to 0x%llx)\n", slot->ds_node_num,
 836                      (long long)slot->ds_last_generation,
 837                      (long long)le64_to_cpu(hb_block->hb_generation));
 838         }
 839
 840         slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
 841
 842         mlog(ML_HEARTBEAT, "Slot %d gen 0x%llx cksum 0x%x "
 843              "seq %llu last %llu changed %u equal %u\n",
 844              slot->ds_node_num, (long long)slot->ds_last_generation,
 845              le32_to_cpu(hb_block->hb_cksum),
 846              (unsigned long long)le64_to_cpu(hb_block->hb_seq),
 847              (unsigned long long)slot->ds_last_time, slot->ds_changed_samples,
 848              slot->ds_equal_samples);
 849
 850         spin_lock(&o2hb_live_lock);
 851
 852 fire_callbacks:
 853         /* dead nodes only come to life after some number of
 854          * changes at any time during their dead time */
 855         if (list_empty(&slot->ds_live_item) &&
 856             slot->ds_changed_samples >= O2HB_LIVE_THRESHOLD) {
 857                 mlog(ML_HEARTBEAT, "Node %d (id 0x%llx) joined my region\n",
 858                      slot->ds_node_num, (long long)slot->ds_last_generation);
 859
 860                 set_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 861
 862                 /* first on the list generates a callback */
 863                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 864                         mlog(ML_HEARTBEAT, "o2hb: Add node %d to live nodes "
 865                              "bitmap\n", slot->ds_node_num);
 866                         set_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 867
 868                         o2hb_queue_node_event(&event, O2HB_NODE_UP_CB, node,
 869                                               slot->ds_node_num);
 870
 871                         changed = 1;
 872                         queued = 1;
 873                 }
 874
 875                 list_add_tail(&slot->ds_live_item,
 876                               &o2hb_live_slots[slot->ds_node_num]);
 877
 878                 slot->ds_equal_samples = 0;
 879
 880                 /* We want to be sure that all nodes agree on the
 881                  * number of milliseconds before a node will be
 882                  * considered dead. The self-fencing timeout is
 883                  * computed from this value, and a discrepancy might
 884                  * result in heartbeat calling a node dead when it
 885                  * hasn't self-fenced yet. */
 886                 slot_dead_ms = le32_to_cpu(hb_block->hb_dead_ms);
 887                 if (slot_dead_ms && slot_dead_ms != dead_ms) {
 888                         /* TODO: Perhaps we can fail the region here. */
 889                         mlog(ML_ERROR, "Node %d on device %s has a dead count "
 890                              "of %u ms, but our count is %u ms.\n"
 891                              "Please double check your configuration values "
 892                              "for 'O2CB_HEARTBEAT_THRESHOLD'\n",
 893                              slot->ds_node_num, reg->hr_dev_name, slot_dead_ms,
 894                              dead_ms);
 895                 }
 896                 goto out;
 897         }
 898
 899         /* if the list is dead, we're done.. */
 900         if (list_empty(&slot->ds_live_item))
 901                 goto out;
 902
 903         /* live nodes only go dead after enough consequtive missed
 904          * samples..  reset the missed counter whenever we see
 905          * activity */
 906         if (slot->ds_equal_samples >= o2hb_dead_threshold || gen_changed) {
 907                 mlog(ML_HEARTBEAT, "Node %d left my region\n",
 908                      slot->ds_node_num);
 909
 910                 clear_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 911
 912                 /* last off the live_slot generates a callback */
 913                 list_del_init(&slot->ds_live_item);
 914                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 915                         mlog(ML_HEARTBEAT, "o2hb: Remove node %d from live "
 916                              "nodes bitmap\n", slot->ds_node_num);
 917                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 918
 919                         /* node can be null */
 920                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB,
 921                                               node, slot->ds_node_num);
 922
 923                         changed = 1;
 924                         queued = 1;
 925                 }
 926
 927                 /* We don't clear this because the node is still
 928                  * actually writing new blocks. */
 929                 if (!gen_changed)
 930                         slot->ds_changed_samples = 0;
 931                 goto out;
 932         }
 933         if (slot->ds_changed_samples) {
 934                 slot->ds_changed_samples = 0;
 935                 slot->ds_equal_samples = 0;
 936         }
 937 out:
 938         spin_unlock(&o2hb_live_lock);
 939
 940         if (queued)
 941                 o2hb_run_event_list(&event);
 942
 943         if (node)
 944                 o2nm_node_put(node);
 945         return changed;
 946 }
 947
 948 static int o2hb_highest_node(unsigned long *nodes, int numbits)
 949 {
 950         return find_last_bit(nodes, numbits);
 951 }
 952
 953 static int o2hb_do_disk_heartbeat(struct o2hb_region *reg)
 954 {
 955         int i, ret, highest_node;
 956         int membership_change = 0, own_slot_ok = 0;
 957         unsigned long configured_nodes[BITS_TO_LONGS(O2NM_MAX_NODES)];
 958         unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 959         struct o2hb_bio_wait_ctxt write_wc;
 960
 961         ret = o2nm_configured_node_map(configured_nodes,
 962                                        sizeof(configured_nodes));
 963         if (ret) {
 964                 mlog_errno(ret);
 965                 goto bail;
 966         }
 967
 968         /*
 969          * If a node is not configured but is in the livemap, we still need
 970          * to read the slot so as to be able to remove it from the livemap.
 971          */
 972         o2hb_fill_node_map(live_node_bitmap, sizeof(live_node_bitmap));
 973         i = -1;
 974         while ((i = find_next_bit(live_node_bitmap,
 975                                   O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
 976                 set_bit(i, configured_nodes);
 977         }
 978
 979         highest_node = o2hb_highest_node(configured_nodes, O2NM_MAX_NODES);
 980         if (highest_node >= O2NM_MAX_NODES) {
 981                 mlog(ML_NOTICE, "o2hb: No configured nodes found!\n");
 982                 ret = -EINVAL;
 983                 goto bail;
 984         }
 985
 986         /* No sense in reading the slots of nodes that don't exist
 987          * yet. Of course, if the node definitions have holes in them
 988          * then we're reading an empty slot anyway... Consider this
 989          * best-effort. */
 990         ret = o2hb_read_slots(reg, highest_node + 1);
 991         if (ret < 0) {
 992                 mlog_errno(ret);
 993                 goto bail;
 994         }
 995
 996         /* With an up to date view of the slots, we can check that no
 997          * other node has been improperly configured to heartbeat in
 998          * our slot. */
 999         own_slot_ok = o2hb_check_own_slot(reg);
1000
1001         /* fill in the proper info for our next heartbeat */
1002         o2hb_prepare_block(reg, reg->hr_generation);
1003
1004         ret = o2hb_issue_node_write(reg, &write_wc);
1005         if (ret < 0) {
1006                 mlog_errno(ret);
1007                 goto bail;
1008         }
1009
1010         i = -1;
1011         while((i = find_next_bit(configured_nodes,
1012                                  O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
1013                 membership_change |= o2hb_check_slot(reg, &reg->hr_slots[i]);
1014         }
1015
1016         /*
1017          * We have to be sure we've advertised ourselves on disk
1018          * before we can go to steady state.  This ensures that
1019          * people we find in our steady state have seen us.
1020          */
1021         o2hb_wait_on_io(reg, &write_wc);
1022         if (write_wc.wc_error) {
1023                 /* Do not re-arm the write timeout on I/O error - we
1024                  * can't be sure that the new block ever made it to
1025                  * disk */
1026                 mlog(ML_ERROR, "Write error %d on device \"%s\"\n",
1027                      write_wc.wc_error, reg->hr_dev_name);
1028                 ret = write_wc.wc_error;
1029                 goto bail;
1030         }
1031
1032         /* Skip disarming the timeout if own slot has stale/bad data */
1033         if (own_slot_ok) {
1034                 o2hb_set_quorum_device(reg);
1035                 o2hb_arm_write_timeout(reg);
1036         }
1037
1038 bail:
1039         /* let the person who launched us know when things are steady */
1040         if (atomic_read(&reg->hr_steady_iterations) != 0) {
1041                 if (!ret && own_slot_ok && !membership_change) {
1042                         if (atomic_dec_and_test(&reg->hr_steady_iterations))
1043                                 wake_up(&o2hb_steady_queue);
1044                 }
1045         }
1046
1047         if (atomic_read(&reg->hr_steady_iterations) != 0) {
1048                 if (atomic_dec_and_test(&reg->hr_unsteady_iterations)) {
1049                         printk(KERN_NOTICE "o2hb: Unable to stabilize "
1050                                "heartbeart on region %s (%s)\n",
1051                                config_item_name(&reg->hr_item),
1052                                reg->hr_dev_name);
1053                         atomic_set(&reg->hr_steady_iterations, 0);
1054                         reg->hr_aborted_start = 1;
1055                         wake_up(&o2hb_steady_queue);
1056                         ret = -EIO;
1057                 }
1058         }
1059
1060         return ret;
1061 }
1062
1063 /*
1064  * we ride the region ref that the region dir holds.  before the region
1065  * dir is removed and drops it ref it will wait to tear down this
1066  * thread.
1067  */
1068 static int o2hb_thread(void *data)
1069 {
1070         int i, ret;
1071         struct o2hb_region *reg = data;
1072         struct o2hb_bio_wait_ctxt write_wc;
1073         ktime_t before_hb, after_hb;
1074         unsigned int elapsed_msec;
1075
1076         mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n");
1077
1078         set_user_nice(current, MIN_NICE);
1079
1080         /* Pin node */
1081         o2nm_depend_this_node();
1082
1083         while (!kthread_should_stop() &&
1084                !reg->hr_unclean_stop && !reg->hr_aborted_start) {
1085                 /* We track the time spent inside
1086                  * o2hb_do_disk_heartbeat so that we avoid more than
1087                  * hr_timeout_ms between disk writes. On busy systems
1088                  * this should result in a heartbeat which is less
1089                  * likely to time itself out. */
1090                 before_hb = ktime_get_real();
1091
1092                 ret = o2hb_do_disk_heartbeat(reg);
1093
1094                 after_hb = ktime_get_real();
1095
1096                 elapsed_msec = (unsigned int)
1097                                 ktime_ms_delta(after_hb, before_hb);
1098
1099                 mlog(ML_HEARTBEAT,
1100                      "start = %lld, end = %lld, msec = %u, ret = %d\n",
1101                      before_hb.tv64, after_hb.tv64, elapsed_msec, ret);
1102
1103                 if (!kthread_should_stop() &&
1104                     elapsed_msec < reg->hr_timeout_ms) {
1105                         /* the kthread api has blocked signals for us so no
1106                          * need to record the return value. */
1107                         msleep_interruptible(reg->hr_timeout_ms - elapsed_msec);
1108                 }
1109         }
1110
1111         o2hb_disarm_write_timeout(reg);
1112
1113         /* unclean stop is only used in very bad situation */
1114         for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
1115                 o2hb_shutdown_slot(&reg->hr_slots[i]);
1116
1117         /* Explicit down notification - avoid forcing the other nodes
1118          * to timeout on this region when we could just as easily
1119          * write a clear generation - thus indicating to them that
1120          * this node has left this region.
1121          */
1122         if (!reg->hr_unclean_stop && !reg->hr_aborted_start) {
1123                 o2hb_prepare_block(reg, 0);
1124                 ret = o2hb_issue_node_write(reg, &write_wc);
1125                 if (ret == 0)
1126                         o2hb_wait_on_io(reg, &write_wc);
1127                 else
1128                         mlog_errno(ret);
1129         }
1130
1131         /* Unpin node */
1132         o2nm_undepend_this_node();
1133
1134         mlog(ML_HEARTBEAT|ML_KTHREAD, "o2hb thread exiting\n");
1135
1136         return 0;
1137 }
1138
1139 #ifdef CONFIG_DEBUG_FS
1140 static int o2hb_debug_open(struct inode *inode, struct file *file)
1141 {
1142         struct o2hb_debug_buf *db = inode->i_private;
1143         struct o2hb_region *reg;
1144         unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1145         unsigned long lts;
1146         char *buf = NULL;
1147         int i = -1;
1148         int out = 0;
1149
1150         /* max_nodes should be the largest bitmap we pass here */
1151         BUG_ON(sizeof(map) < db->db_size);
1152
1153         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1154         if (!buf)
1155                 goto bail;
1156
1157         switch (db->db_type) {
1158         case O2HB_DB_TYPE_LIVENODES:
1159         case O2HB_DB_TYPE_LIVEREGIONS:
1160         case O2HB_DB_TYPE_QUORUMREGIONS:
1161         case O2HB_DB_TYPE_FAILEDREGIONS:
1162                 spin_lock(&o2hb_live_lock);
1163                 memcpy(map, db->db_data, db->db_size);
1164                 spin_unlock(&o2hb_live_lock);
1165                 break;
1166
1167         case O2HB_DB_TYPE_REGION_LIVENODES:
1168                 spin_lock(&o2hb_live_lock);
1169                 reg = (struct o2hb_region *)db->db_data;
1170                 memcpy(map, reg->hr_live_node_bitmap, db->db_size);
1171                 spin_unlock(&o2hb_live_lock);
1172                 break;
1173
1174         case O2HB_DB_TYPE_REGION_NUMBER:
1175                 reg = (struct o2hb_region *)db->db_data;
1176                 out += snprintf(buf + out, PAGE_SIZE - out, "%d\n",
1177                                 reg->hr_region_num);
1178                 goto done;
1179
1180         case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
1181                 reg = (struct o2hb_region *)db->db_data;
1182                 lts = reg->hr_last_timeout_start;
1183                 /* If 0, it has never been set before */
1184                 if (lts)
1185                         lts = jiffies_to_msecs(jiffies - lts);
1186                 out += snprintf(buf + out, PAGE_SIZE - out, "%lu\n", lts);
1187                 goto done;
1188
1189         case O2HB_DB_TYPE_REGION_PINNED:
1190                 reg = (struct o2hb_region *)db->db_data;
1191                 out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
1192                                 !!reg->hr_item_pinned);
1193                 goto done;
1194
1195         default:
1196                 goto done;
1197         }
1198
1199         while ((i = find_next_bit(map, db->db_len, i + 1)) < db->db_len)
1200                 out += snprintf(buf + out, PAGE_SIZE - out, "%d ", i);
1201         out += snprintf(buf + out, PAGE_SIZE - out, "\n");
1202
1203 done:
1204         i_size_write(inode, out);
1205
1206         file->private_data = buf;
1207
1208         return 0;
1209 bail:
1210         return -ENOMEM;
1211 }
1212
1213 static int o2hb_debug_release(struct inode *inode, struct file *file)
1214 {
1215         kfree(file->private_data);
1216         return 0;
1217 }
1218
1219 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1220                                  size_t nbytes, loff_t *ppos)
1221 {
1222         return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
1223                                        i_size_read(file->f_mapping->host));
1224 }
1225 #else
1226 static int o2hb_debug_open(struct inode *inode, struct file *file)
1227 {
1228         return 0;
1229 }
1230 static int o2hb_debug_release(struct inode *inode, struct file *file)
1231 {
1232         return 0;
1233 }
1234 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1235                                size_t nbytes, loff_t *ppos)
1236 {
1237         return 0;
1238 }
1239 #endif  /* CONFIG_DEBUG_FS */
1240
1241 static const struct file_operations o2hb_debug_fops = {
1242         .open =         o2hb_debug_open,
1243         .release =      o2hb_debug_release,
1244         .read =         o2hb_debug_read,
1245         .llseek =       generic_file_llseek,
1246 };
1247
1248 void o2hb_exit(void)
1249 {
1250         kfree(o2hb_db_livenodes);
1251         kfree(o2hb_db_liveregions);
1252         kfree(o2hb_db_quorumregions);
1253         kfree(o2hb_db_failedregions);
1254         debugfs_remove(o2hb_debug_failedregions);
1255         debugfs_remove(o2hb_debug_quorumregions);
1256         debugfs_remove(o2hb_debug_liveregions);
1257         debugfs_remove(o2hb_debug_livenodes);
1258         debugfs_remove(o2hb_debug_dir);
1259 }
1260
1261 static struct dentry *o2hb_debug_create(const char *name, struct dentry *dir,
1262                                         struct o2hb_debug_buf **db, int db_len,
1263                                         int type, int size, int len, void *data)
1264 {
1265         *db = kmalloc(db_len, GFP_KERNEL);
1266         if (!*db)
1267                 return NULL;
1268
1269         (*db)->db_type = type;
1270         (*db)->db_size = size;
1271         (*db)->db_len = len;
1272         (*db)->db_data = data;
1273
1274         return debugfs_create_file(name, S_IFREG|S_IRUSR, dir, *db,
1275                                    &o2hb_debug_fops);
1276 }
1277
1278 static int o2hb_debug_init(void)
1279 {
1280         int ret = -ENOMEM;
1281
1282         o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
1283         if (!o2hb_debug_dir) {
1284                 mlog_errno(ret);
1285                 goto bail;
1286         }
1287
1288         o2hb_debug_livenodes = o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1289                                                  o2hb_debug_dir,
1290                                                  &o2hb_db_livenodes,
1291                                                  sizeof(*o2hb_db_livenodes),
1292                                                  O2HB_DB_TYPE_LIVENODES,
1293                                                  sizeof(o2hb_live_node_bitmap),
1294                                                  O2NM_MAX_NODES,
1295                                                  o2hb_live_node_bitmap);
1296         if (!o2hb_debug_livenodes) {
1297                 mlog_errno(ret);
1298                 goto bail;
1299         }
1300
1301         o2hb_debug_liveregions = o2hb_debug_create(O2HB_DEBUG_LIVEREGIONS,
1302                                                    o2hb_debug_dir,
1303                                                    &o2hb_db_liveregions,
1304                                                    sizeof(*o2hb_db_liveregions),
1305                                                    O2HB_DB_TYPE_LIVEREGIONS,
1306                                                    sizeof(o2hb_live_region_bitmap),
1307                                                    O2NM_MAX_REGIONS,
1308                                                    o2hb_live_region_bitmap);
1309         if (!o2hb_debug_liveregions) {
1310                 mlog_errno(ret);
1311                 goto bail;
1312         }
1313
1314         o2hb_debug_quorumregions =
1315                         o2hb_debug_create(O2HB_DEBUG_QUORUMREGIONS,
1316                                           o2hb_debug_dir,
1317                                           &o2hb_db_quorumregions,
1318                                           sizeof(*o2hb_db_quorumregions),
1319                                           O2HB_DB_TYPE_QUORUMREGIONS,
1320                                           sizeof(o2hb_quorum_region_bitmap),
1321                                           O2NM_MAX_REGIONS,
1322                                           o2hb_quorum_region_bitmap);
1323         if (!o2hb_debug_quorumregions) {
1324                 mlog_errno(ret);
1325                 goto bail;
1326         }
1327
1328         o2hb_debug_failedregions =
1329                         o2hb_debug_create(O2HB_DEBUG_FAILEDREGIONS,
1330                                           o2hb_debug_dir,
1331                                           &o2hb_db_failedregions,
1332                                           sizeof(*o2hb_db_failedregions),
1333                                           O2HB_DB_TYPE_FAILEDREGIONS,
1334                                           sizeof(o2hb_failed_region_bitmap),
1335                                           O2NM_MAX_REGIONS,
1336                                           o2hb_failed_region_bitmap);
1337         if (!o2hb_debug_failedregions) {
1338                 mlog_errno(ret);
1339                 goto bail;
1340         }
1341
1342         ret = 0;
1343 bail:
1344         if (ret)
1345                 o2hb_exit();
1346
1347         return ret;
1348 }
1349
1350 int o2hb_init(void)
1351 {
1352         int i;
1353
1354         for (i = 0; i < ARRAY_SIZE(o2hb_callbacks); i++)
1355                 INIT_LIST_HEAD(&o2hb_callbacks[i].list);
1356
1357         for (i = 0; i < ARRAY_SIZE(o2hb_live_slots); i++)
1358                 INIT_LIST_HEAD(&o2hb_live_slots[i]);
1359
1360         INIT_LIST_HEAD(&o2hb_node_events);
1361
1362         memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
1363         memset(o2hb_region_bitmap, 0, sizeof(o2hb_region_bitmap));
1364         memset(o2hb_live_region_bitmap, 0, sizeof(o2hb_live_region_bitmap));
1365         memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
1366         memset(o2hb_failed_region_bitmap, 0, sizeof(o2hb_failed_region_bitmap));
1367
1368         o2hb_dependent_users = 0;
1369
1370         return o2hb_debug_init();
1371 }
1372
1373 /* if we're already in a callback then we're already serialized by the sem */
1374 static void o2hb_fill_node_map_from_callback(unsigned long *map,
1375                                              unsigned bytes)
1376 {
1377         BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1378
1379         memcpy(map, &o2hb_live_node_bitmap, bytes);
1380 }
1381
1382 /*
1383  * get a map of all nodes that are heartbeating in any regions
1384  */
1385 void o2hb_fill_node_map(unsigned long *map, unsigned bytes)
1386 {
1387         /* callers want to serialize this map and callbacks so that they
1388          * can trust that they don't miss nodes coming to the party */
1389         down_read(&o2hb_callback_sem);
1390         spin_lock(&o2hb_live_lock);
1391         o2hb_fill_node_map_from_callback(map, bytes);
1392         spin_unlock(&o2hb_live_lock);
1393         up_read(&o2hb_callback_sem);
1394 }
1395 EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
1396
1397 /*
1398  * heartbeat configfs bits.  The heartbeat set is a default set under
1399  * the cluster set in nodemanager.c.
1400  */
1401
1402 static struct o2hb_region *to_o2hb_region(struct config_item *item)
1403 {
1404         return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
1405 }
1406
1407 /* drop_item only drops its ref after killing the thread, nothing should
1408  * be using the region anymore.  this has to clean up any state that
1409  * attributes might have built up. */
1410 static void o2hb_region_release(struct config_item *item)
1411 {
1412         int i;
1413         struct page *page;
1414         struct o2hb_region *reg = to_o2hb_region(item);
1415
1416         mlog(ML_HEARTBEAT, "hb region release (%s)\n", reg->hr_dev_name);
1417
1418         kfree(reg->hr_tmp_block);
1419
1420         if (reg->hr_slot_data) {
1421                 for (i = 0; i < reg->hr_num_pages; i++) {
1422                         page = reg->hr_slot_data[i];
1423                         if (page)
1424                                 __free_page(page);
1425                 }
1426                 kfree(reg->hr_slot_data);
1427         }
1428
1429         if (reg->hr_bdev)
1430                 blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1431
1432         kfree(reg->hr_slots);
1433
1434         kfree(reg->hr_db_regnum);
1435         kfree(reg->hr_db_livenodes);
1436         debugfs_remove(reg->hr_debug_livenodes);
1437         debugfs_remove(reg->hr_debug_regnum);
1438         debugfs_remove(reg->hr_debug_elapsed_time);
1439         debugfs_remove(reg->hr_debug_pinned);
1440         debugfs_remove(reg->hr_debug_dir);
1441
1442         spin_lock(&o2hb_live_lock);
1443         list_del(&reg->hr_all_item);
1444         spin_unlock(&o2hb_live_lock);
1445
1446         kfree(reg);
1447 }
1448
1449 static int o2hb_read_block_input(struct o2hb_region *reg,
1450                                  const char *page,
1451                                  size_t count,
1452                                  unsigned long *ret_bytes,
1453                                  unsigned int *ret_bits)
1454 {
1455         unsigned long bytes;
1456         char *p = (char *)page;
1457
1458         bytes = simple_strtoul(p, &p, 0);
1459         if (!p || (*p && (*p != '\n')))
1460                 return -EINVAL;
1461
1462         /* Heartbeat and fs min / max block sizes are the same. */
1463         if (bytes > 4096 || bytes < 512)
1464                 return -ERANGE;
1465         if (hweight16(bytes) != 1)
1466                 return -EINVAL;
1467
1468         if (ret_bytes)
1469                 *ret_bytes = bytes;
1470         if (ret_bits)
1471                 *ret_bits = ffs(bytes) - 1;
1472
1473         return 0;
1474 }
1475
1476 static ssize_t o2hb_region_block_bytes_read(struct o2hb_region *reg,
1477                                             char *page)
1478 {
1479         return sprintf(page, "%u\n", reg->hr_block_bytes);
1480 }
1481
1482 static ssize_t o2hb_region_block_bytes_write(struct o2hb_region *reg,
1483                                              const char *page,
1484                                              size_t count)
1485 {
1486         int status;
1487         unsigned long block_bytes;
1488         unsigned int block_bits;
1489
1490         if (reg->hr_bdev)
1491                 return -EINVAL;
1492
1493         status = o2hb_read_block_input(reg, page, count,
1494                                        &block_bytes, &block_bits);
1495         if (status)
1496                 return status;
1497
1498         reg->hr_block_bytes = (unsigned int)block_bytes;
1499         reg->hr_block_bits = block_bits;
1500
1501         return count;
1502 }
1503
1504 static ssize_t o2hb_region_start_block_read(struct o2hb_region *reg,
1505                                             char *page)
1506 {
1507         return sprintf(page, "%llu\n", reg->hr_start_block);
1508 }
1509
1510 static ssize_t o2hb_region_start_block_write(struct o2hb_region *reg,
1511                                              const char *page,
1512                                              size_t count)
1513 {
1514         unsigned long long tmp;
1515         char *p = (char *)page;
1516
1517         if (reg->hr_bdev)
1518                 return -EINVAL;
1519
1520         tmp = simple_strtoull(p, &p, 0);
1521         if (!p || (*p && (*p != '\n')))
1522                 return -EINVAL;
1523
1524         reg->hr_start_block = tmp;
1525
1526         return count;
1527 }
1528
1529 static ssize_t o2hb_region_blocks_read(struct o2hb_region *reg,
1530                                        char *page)
1531 {
1532         return sprintf(page, "%d\n", reg->hr_blocks);
1533 }
1534
1535 static ssize_t o2hb_region_blocks_write(struct o2hb_region *reg,
1536                                         const char *page,
1537                                         size_t count)
1538 {
1539         unsigned long tmp;
1540         char *p = (char *)page;
1541
1542         if (reg->hr_bdev)
1543                 return -EINVAL;
1544
1545         tmp = simple_strtoul(p, &p, 0);
1546         if (!p || (*p && (*p != '\n')))
1547                 return -EINVAL;
1548
1549         if (tmp > O2NM_MAX_NODES || tmp == 0)
1550                 return -ERANGE;
1551
1552         reg->hr_blocks = (unsigned int)tmp;
1553
1554         return count;
1555 }
1556
1557 static ssize_t o2hb_region_dev_read(struct o2hb_region *reg,
1558                                     char *page)
1559 {
1560         unsigned int ret = 0;
1561
1562         if (reg->hr_bdev)
1563                 ret = sprintf(page, "%s\n", reg->hr_dev_name);
1564
1565         return ret;
1566 }
1567
1568 static void o2hb_init_region_params(struct o2hb_region *reg)
1569 {
1570         reg->hr_slots_per_page = PAGE_CACHE_SIZE >> reg->hr_block_bits;
1571         reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
1572
1573         mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
1574              reg->hr_start_block, reg->hr_blocks);
1575         mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
1576              reg->hr_block_bytes, reg->hr_block_bits);
1577         mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
1578         mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
1579 }
1580
1581 static int o2hb_map_slot_data(struct o2hb_region *reg)
1582 {
1583         int i, j;
1584         unsigned int last_slot;
1585         unsigned int spp = reg->hr_slots_per_page;
1586         struct page *page;
1587         char *raw;
1588         struct o2hb_disk_slot *slot;
1589
1590         reg->hr_tmp_block = kmalloc(reg->hr_block_bytes, GFP_KERNEL);
1591         if (reg->hr_tmp_block == NULL)
1592                 return -ENOMEM;
1593
1594         reg->hr_slots = kcalloc(reg->hr_blocks,
1595                                 sizeof(struct o2hb_disk_slot), GFP_KERNEL);
1596         if (reg->hr_slots == NULL)
1597                 return -ENOMEM;
1598
1599         for(i = 0; i < reg->hr_blocks; i++) {
1600                 slot = &reg->hr_slots[i];
1601                 slot->ds_node_num = i;
1602                 INIT_LIST_HEAD(&slot->ds_live_item);
1603                 slot->ds_raw_block = NULL;
1604         }
1605
1606         reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
1607         mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
1608                            "at %u blocks per page\n",
1609              reg->hr_num_pages, reg->hr_blocks, spp);
1610
1611         reg->hr_slot_data = kcalloc(reg->hr_num_pages, sizeof(struct page *),
1612                                     GFP_KERNEL);
1613         if (!reg->hr_slot_data)
1614                 return -ENOMEM;
1615
1616         for(i = 0; i < reg->hr_num_pages; i++) {
1617                 page = alloc_page(GFP_KERNEL);
1618                 if (!page)
1619                         return -ENOMEM;
1620
1621                 reg->hr_slot_data[i] = page;
1622
1623                 last_slot = i * spp;
1624                 raw = page_address(page);
1625                 for (j = 0;
1626                      (j < spp) && ((j + last_slot) < reg->hr_blocks);
1627                      j++) {
1628                         BUG_ON((j + last_slot) >= reg->hr_blocks);
1629
1630                         slot = &reg->hr_slots[j + last_slot];
1631                         slot->ds_raw_block =
1632                                 (struct o2hb_disk_heartbeat_block *) raw;
1633
1634                         raw += reg->hr_block_bytes;
1635                 }
1636         }
1637
1638         return 0;
1639 }
1640
1641 /* Read in all the slots available and populate the tracking
1642  * structures so that we can start with a baseline idea of what's
1643  * there. */
1644 static int o2hb_populate_slot_data(struct o2hb_region *reg)
1645 {
1646         int ret, i;
1647         struct o2hb_disk_slot *slot;
1648         struct o2hb_disk_heartbeat_block *hb_block;
1649
1650         ret = o2hb_read_slots(reg, reg->hr_blocks);
1651         if (ret)
1652                 goto out;
1653
1654         /* We only want to get an idea of the values initially in each
1655          * slot, so we do no verification - o2hb_check_slot will
1656          * actually determine if each configured slot is valid and
1657          * whether any values have changed. */
1658         for(i = 0; i < reg->hr_blocks; i++) {
1659                 slot = &reg->hr_slots[i];
1660                 hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
1661
1662                 /* Only fill the values that o2hb_check_slot uses to
1663                  * determine changing slots */
1664                 slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
1665                 slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
1666         }
1667
1668 out:
1669         return ret;
1670 }
1671
1672 /* this is acting as commit; we set up all of hr_bdev and hr_task or nothing */
1673 static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
1674                                      const char *page,
1675                                      size_t count)
1676 {
1677         struct task_struct *hb_task;
1678         long fd;
1679         int sectsize;
1680         char *p = (char *)page;
1681         struct fd f;
1682         struct inode *inode;
1683         ssize_t ret = -EINVAL;
1684         int live_threshold;
1685
1686         if (reg->hr_bdev)
1687                 goto out;
1688
1689         /* We can't heartbeat without having had our node number
1690          * configured yet. */
1691         if (o2nm_this_node() == O2NM_MAX_NODES)
1692                 goto out;
1693
1694         fd = simple_strtol(p, &p, 0);
1695         if (!p || (*p && (*p != '\n')))
1696                 goto out;
1697
1698         if (fd < 0 || fd >= INT_MAX)
1699                 goto out;
1700
1701         f = fdget(fd);
1702         if (f.file == NULL)
1703                 goto out;
1704
1705         if (reg->hr_blocks == 0 || reg->hr_start_block == 0 ||
1706             reg->hr_block_bytes == 0)
1707                 goto out2;
1708
1709         inode = igrab(f.file->f_mapping->host);
1710         if (inode == NULL)
1711                 goto out2;
1712
1713         if (!S_ISBLK(inode->i_mode))
1714                 goto out3;
1715
1716         reg->hr_bdev = I_BDEV(f.file->f_mapping->host);
1717         ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ, NULL);
1718         if (ret) {
1719                 reg->hr_bdev = NULL;
1720                 goto out3;
1721         }
1722         inode = NULL;
1723
1724         bdevname(reg->hr_bdev, reg->hr_dev_name);
1725
1726         sectsize = bdev_logical_block_size(reg->hr_bdev);
1727         if (sectsize != reg->hr_block_bytes) {
1728                 mlog(ML_ERROR,
1729                      "blocksize %u incorrect for device, expected %d",
1730                      reg->hr_block_bytes, sectsize);
1731                 ret = -EINVAL;
1732                 goto out3;
1733         }
1734
1735         o2hb_init_region_params(reg);
1736
1737         /* Generation of zero is invalid */
1738         do {
1739                 get_random_bytes(&reg->hr_generation,
1740                                  sizeof(reg->hr_generation));
1741         } while (reg->hr_generation == 0);
1742
1743         ret = o2hb_map_slot_data(reg);
1744         if (ret) {
1745                 mlog_errno(ret);
1746                 goto out3;
1747         }
1748
1749         ret = o2hb_populate_slot_data(reg);
1750         if (ret) {
1751                 mlog_errno(ret);
1752                 goto out3;
1753         }
1754
1755         INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
1756
1757         /*
1758          * A node is considered live after it has beat LIVE_THRESHOLD
1759          * times.  We're not steady until we've given them a chance
1760          * _after_ our first read.
1761          * The default threshold is bare minimum so as to limit the delay
1762          * during mounts. For global heartbeat, the threshold doubled for the
1763          * first region.
1764          */
1765         live_threshold = O2HB_LIVE_THRESHOLD;
1766         if (o2hb_global_heartbeat_active()) {
1767                 spin_lock(&o2hb_live_lock);
1768                 if (bitmap_weight(o2hb_region_bitmap, O2NM_MAX_REGIONS) == 1)
1769                         live_threshold <<= 1;
1770                 spin_unlock(&o2hb_live_lock);
1771         }
1772         ++live_threshold;
1773         atomic_set(&reg->hr_steady_iterations, live_threshold);
1774         /* unsteady_iterations is double the steady_iterations */
1775         atomic_set(&reg->hr_unsteady_iterations, (live_threshold << 1));
1776
1777         hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
1778                               reg->hr_item.ci_name);
1779         if (IS_ERR(hb_task)) {
1780                 ret = PTR_ERR(hb_task);
1781                 mlog_errno(ret);
1782                 goto out3;
1783         }
1784
1785         spin_lock(&o2hb_live_lock);
1786         reg->hr_task = hb_task;
1787         spin_unlock(&o2hb_live_lock);
1788
1789         ret = wait_event_interruptible(o2hb_steady_queue,
1790                                 atomic_read(&reg->hr_steady_iterations) == 0);
1791         if (ret) {
1792                 atomic_set(&reg->hr_steady_iterations, 0);
1793                 reg->hr_aborted_start = 1;
1794         }
1795
1796         if (reg->hr_aborted_start) {
1797                 ret = -EIO;
1798                 goto out3;
1799         }
1800
1801         /* Ok, we were woken.  Make sure it wasn't by drop_item() */
1802         spin_lock(&o2hb_live_lock);
1803         hb_task = reg->hr_task;
1804         if (o2hb_global_heartbeat_active())
1805                 set_bit(reg->hr_region_num, o2hb_live_region_bitmap);
1806         spin_unlock(&o2hb_live_lock);
1807
1808         if (hb_task)
1809                 ret = count;
1810         else
1811                 ret = -EIO;
1812
1813         if (hb_task && o2hb_global_heartbeat_active())
1814                 printk(KERN_NOTICE "o2hb: Heartbeat started on region %s (%s)\n",
1815                        config_item_name(&reg->hr_item), reg->hr_dev_name);
1816
1817 out3:
1818         iput(inode);
1819 out2:
1820         fdput(f);
1821 out:
1822         if (ret < 0) {
1823                 if (reg->hr_bdev) {
1824                         blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1825                         reg->hr_bdev = NULL;
1826                 }
1827         }
1828         return ret;
1829 }
1830
1831 static ssize_t o2hb_region_pid_read(struct o2hb_region *reg,
1832                                       char *page)
1833 {
1834         pid_t pid = 0;
1835
1836         spin_lock(&o2hb_live_lock);
1837         if (reg->hr_task)
1838                 pid = task_pid_nr(reg->hr_task);
1839         spin_unlock(&o2hb_live_lock);
1840
1841         if (!pid)
1842                 return 0;
1843
1844         return sprintf(page, "%u\n", pid);
1845 }
1846
1847 struct o2hb_region_attribute {
1848         struct configfs_attribute attr;
1849         ssize_t (*show)(struct o2hb_region *, char *);
1850         ssize_t (*store)(struct o2hb_region *, const char *, size_t);
1851 };
1852
1853 static struct o2hb_region_attribute o2hb_region_attr_block_bytes = {
1854         .attr   = { .ca_owner = THIS_MODULE,
1855                     .ca_name = "block_bytes",
1856                     .ca_mode = S_IRUGO | S_IWUSR },
1857         .show   = o2hb_region_block_bytes_read,
1858         .store  = o2hb_region_block_bytes_write,
1859 };
1860
1861 static struct o2hb_region_attribute o2hb_region_attr_start_block = {
1862         .attr   = { .ca_owner = THIS_MODULE,
1863                     .ca_name = "start_block",
1864                     .ca_mode = S_IRUGO | S_IWUSR },
1865         .show   = o2hb_region_start_block_read,
1866         .store  = o2hb_region_start_block_write,
1867 };
1868
1869 static struct o2hb_region_attribute o2hb_region_attr_blocks = {
1870         .attr   = { .ca_owner = THIS_MODULE,
1871                     .ca_name = "blocks",
1872                     .ca_mode = S_IRUGO | S_IWUSR },
1873         .show   = o2hb_region_blocks_read,
1874         .store  = o2hb_region_blocks_write,
1875 };
1876
1877 static struct o2hb_region_attribute o2hb_region_attr_dev = {
1878         .attr   = { .ca_owner = THIS_MODULE,
1879                     .ca_name = "dev",
1880                     .ca_mode = S_IRUGO | S_IWUSR },
1881         .show   = o2hb_region_dev_read,
1882         .store  = o2hb_region_dev_write,
1883 };
1884
1885 static struct o2hb_region_attribute o2hb_region_attr_pid = {
1886        .attr   = { .ca_owner = THIS_MODULE,
1887                    .ca_name = "pid",
1888                    .ca_mode = S_IRUGO | S_IRUSR },
1889        .show   = o2hb_region_pid_read,
1890 };
1891
1892 static struct configfs_attribute *o2hb_region_attrs[] = {
1893         &o2hb_region_attr_block_bytes.attr,
1894         &o2hb_region_attr_start_block.attr,
1895         &o2hb_region_attr_blocks.attr,
1896         &o2hb_region_attr_dev.attr,
1897         &o2hb_region_attr_pid.attr,
1898         NULL,
1899 };
1900
1901 static ssize_t o2hb_region_show(struct config_item *item,
1902                                 struct configfs_attribute *attr,
1903                                 char *page)
1904 {
1905         struct o2hb_region *reg = to_o2hb_region(item);
1906         struct o2hb_region_attribute *o2hb_region_attr =
1907                 container_of(attr, struct o2hb_region_attribute, attr);
1908         ssize_t ret = 0;
1909
1910         if (o2hb_region_attr->show)
1911                 ret = o2hb_region_attr->show(reg, page);
1912         return ret;
1913 }
1914
1915 static ssize_t o2hb_region_store(struct config_item *item,
1916                                  struct configfs_attribute *attr,
1917                                  const char *page, size_t count)
1918 {
1919         struct o2hb_region *reg = to_o2hb_region(item);
1920         struct o2hb_region_attribute *o2hb_region_attr =
1921                 container_of(attr, struct o2hb_region_attribute, attr);
1922         ssize_t ret = -EINVAL;
1923
1924         if (o2hb_region_attr->store)
1925                 ret = o2hb_region_attr->store(reg, page, count);
1926         return ret;
1927 }
1928
1929 static struct configfs_item_operations o2hb_region_item_ops = {
1930         .release                = o2hb_region_release,
1931         .show_attribute         = o2hb_region_show,
1932         .store_attribute        = o2hb_region_store,
1933 };
1934
1935 static struct config_item_type o2hb_region_type = {
1936         .ct_item_ops    = &o2hb_region_item_ops,
1937         .ct_attrs       = o2hb_region_attrs,
1938         .ct_owner       = THIS_MODULE,
1939 };
1940
1941 /* heartbeat set */
1942
1943 struct o2hb_heartbeat_group {
1944         struct config_group hs_group;
1945         /* some stuff? */
1946 };
1947
1948 static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
1949 {
1950         return group ?
1951                 container_of(group, struct o2hb_heartbeat_group, hs_group)
1952                 : NULL;
1953 }
1954
1955 static int o2hb_debug_region_init(struct o2hb_region *reg, struct dentry *dir)
1956 {
1957         int ret = -ENOMEM;
1958
1959         reg->hr_debug_dir =
1960                 debugfs_create_dir(config_item_name(&reg->hr_item), dir);
1961         if (!reg->hr_debug_dir) {
1962                 mlog_errno(ret);
1963                 goto bail;
1964         }
1965
1966         reg->hr_debug_livenodes =
1967                         o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1968                                           reg->hr_debug_dir,
1969                                           &(reg->hr_db_livenodes),
1970                                           sizeof(*(reg->hr_db_livenodes)),
1971                                           O2HB_DB_TYPE_REGION_LIVENODES,
1972                                           sizeof(reg->hr_live_node_bitmap),
1973                                           O2NM_MAX_NODES, reg);
1974         if (!reg->hr_debug_livenodes) {
1975                 mlog_errno(ret);
1976                 goto bail;
1977         }
1978
1979         reg->hr_debug_regnum =
1980                         o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER,
1981                                           reg->hr_debug_dir,
1982                                           &(reg->hr_db_regnum),
1983                                           sizeof(*(reg->hr_db_regnum)),
1984                                           O2HB_DB_TYPE_REGION_NUMBER,
1985                                           0, O2NM_MAX_NODES, reg);
1986         if (!reg->hr_debug_regnum) {
1987                 mlog_errno(ret);
1988                 goto bail;
1989         }
1990
1991         reg->hr_debug_elapsed_time =
1992                         o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME,
1993                                           reg->hr_debug_dir,
1994                                           &(reg->hr_db_elapsed_time),
1995                                           sizeof(*(reg->hr_db_elapsed_time)),
1996                                           O2HB_DB_TYPE_REGION_ELAPSED_TIME,
1997                                           0, 0, reg);
1998         if (!reg->hr_debug_elapsed_time) {
1999                 mlog_errno(ret);
2000                 goto bail;
2001         }
2002
2003         reg->hr_debug_pinned =
2004                         o2hb_debug_create(O2HB_DEBUG_REGION_PINNED,
2005                                           reg->hr_debug_dir,
2006                                           &(reg->hr_db_pinned),
2007                                           sizeof(*(reg->hr_db_pinned)),
2008                                           O2HB_DB_TYPE_REGION_PINNED,
2009                                           0, 0, reg);
2010         if (!reg->hr_debug_pinned) {
2011                 mlog_errno(ret);
2012                 goto bail;
2013         }
2014
2015         ret = 0;
2016 bail:
2017         return ret;
2018 }
2019
2020 static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
2021                                                           const char *name)
2022 {
2023         struct o2hb_region *reg = NULL;
2024         int ret;
2025
2026         reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
2027         if (reg == NULL)
2028                 return ERR_PTR(-ENOMEM);
2029
2030         if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
2031                 ret = -ENAMETOOLONG;
2032                 goto free;
2033         }
2034
2035         spin_lock(&o2hb_live_lock);
2036         reg->hr_region_num = 0;
2037         if (o2hb_global_heartbeat_active()) {
2038                 reg->hr_region_num = find_first_zero_bit(o2hb_region_bitmap,
2039                                                          O2NM_MAX_REGIONS);
2040                 if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
2041                         spin_unlock(&o2hb_live_lock);
2042                         ret = -EFBIG;
2043                         goto free;
2044                 }
2045                 set_bit(reg->hr_region_num, o2hb_region_bitmap);
2046         }
2047         list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
2048         spin_unlock(&o2hb_live_lock);
2049
2050         config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
2051
2052         ret = o2hb_debug_region_init(reg, o2hb_debug_dir);
2053         if (ret) {
2054                 config_item_put(&reg->hr_item);
2055                 goto free;
2056         }
2057
2058         return &reg->hr_item;
2059 free:
2060         kfree(reg);
2061         return ERR_PTR(ret);
2062 }
2063
2064 static void o2hb_heartbeat_group_drop_item(struct config_group *group,
2065                                            struct config_item *item)
2066 {
2067         struct task_struct *hb_task;
2068         struct o2hb_region *reg = to_o2hb_region(item);
2069         int quorum_region = 0;
2070
2071         /* stop the thread when the user removes the region dir */
2072         spin_lock(&o2hb_live_lock);
2073         hb_task = reg->hr_task;
2074         reg->hr_task = NULL;
2075         reg->hr_item_dropped = 1;
2076         spin_unlock(&o2hb_live_lock);
2077
2078         if (hb_task)
2079                 kthread_stop(hb_task);
2080
2081         if (o2hb_global_heartbeat_active()) {
2082                 spin_lock(&o2hb_live_lock);
2083                 clear_bit(reg->hr_region_num, o2hb_region_bitmap);
2084                 clear_bit(reg->hr_region_num, o2hb_live_region_bitmap);
2085                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
2086                         quorum_region = 1;
2087                 clear_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
2088                 spin_unlock(&o2hb_live_lock);
2089                 printk(KERN_NOTICE "o2hb: Heartbeat %s on region %s (%s)\n",
2090                        ((atomic_read(&reg->hr_steady_iterations) == 0) ?
2091                         "stopped" : "start aborted"), config_item_name(item),
2092                        reg->hr_dev_name);
2093         }
2094
2095         /*
2096          * If we're racing a dev_write(), we need to wake them.  They will
2097          * check reg->hr_task
2098          */
2099         if (atomic_read(&reg->hr_steady_iterations) != 0) {
2100                 reg->hr_aborted_start = 1;
2101                 atomic_set(&reg->hr_steady_iterations, 0);
2102                 wake_up(&o2hb_steady_queue);
2103         }
2104
2105         config_item_put(item);
2106
2107         if (!o2hb_global_heartbeat_active() || !quorum_region)
2108                 return;
2109
2110         /*
2111          * If global heartbeat active and there are dependent users,
2112          * pin all regions if quorum region count <= CUT_OFF
2113          */
2114         spin_lock(&o2hb_live_lock);
2115
2116         if (!o2hb_dependent_users)
2117                 goto unlock;
2118
2119         if (bitmap_weight(o2hb_quorum_region_bitmap,
2120                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2121                 o2hb_region_pin(NULL);
2122
2123 unlock:
2124         spin_unlock(&o2hb_live_lock);
2125 }
2126
2127 struct o2hb_heartbeat_group_attribute {
2128         struct configfs_attribute attr;
2129         ssize_t (*show)(struct o2hb_heartbeat_group *, char *);
2130         ssize_t (*store)(struct o2hb_heartbeat_group *, const char *, size_t);
2131 };
2132
2133 static ssize_t o2hb_heartbeat_group_show(struct config_item *item,
2134                                          struct configfs_attribute *attr,
2135                                          char *page)
2136 {
2137         struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
2138         struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
2139                 container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
2140         ssize_t ret = 0;
2141
2142         if (o2hb_heartbeat_group_attr->show)
2143                 ret = o2hb_heartbeat_group_attr->show(reg, page);
2144         return ret;
2145 }
2146
2147 static ssize_t o2hb_heartbeat_group_store(struct config_item *item,
2148                                           struct configfs_attribute *attr,
2149                                           const char *page, size_t count)
2150 {
2151         struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
2152         struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
2153                 container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
2154         ssize_t ret = -EINVAL;
2155
2156         if (o2hb_heartbeat_group_attr->store)
2157                 ret = o2hb_heartbeat_group_attr->store(reg, page, count);
2158         return ret;
2159 }
2160
2161 static ssize_t o2hb_heartbeat_group_threshold_show(struct o2hb_heartbeat_group *group,
2162                                                      char *page)
2163 {
2164         return sprintf(page, "%u\n", o2hb_dead_threshold);
2165 }
2166
2167 static ssize_t o2hb_heartbeat_group_threshold_store(struct o2hb_heartbeat_group *group,
2168                                                     const char *page,
2169                                                     size_t count)
2170 {
2171         unsigned long tmp;
2172         char *p = (char *)page;
2173
2174         tmp = simple_strtoul(p, &p, 10);
2175         if (!p || (*p && (*p != '\n')))
2176                 return -EINVAL;
2177
2178         /* this will validate ranges for us. */
2179         o2hb_dead_threshold_set((unsigned int) tmp);
2180
2181         return count;
2182 }
2183
2184 static
2185 ssize_t o2hb_heartbeat_group_mode_show(struct o2hb_heartbeat_group *group,
2186                                        char *page)
2187 {
2188         return sprintf(page, "%s\n",
2189                        o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
2190 }
2191
2192 static
2193 ssize_t o2hb_heartbeat_group_mode_store(struct o2hb_heartbeat_group *group,
2194                                         const char *page, size_t count)
2195 {
2196         unsigned int i;
2197         int ret;
2198         size_t len;
2199
2200         len = (page[count - 1] == '\n') ? count - 1 : count;
2201         if (!len)
2202                 return -EINVAL;
2203
2204         for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
2205                 if (strncasecmp(page, o2hb_heartbeat_mode_desc[i], len))
2206                         continue;
2207
2208                 ret = o2hb_global_heartbeat_mode_set(i);
2209                 if (!ret)
2210                         printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
2211                                o2hb_heartbeat_mode_desc[i]);
2212                 return count;
2213         }
2214
2215         return -EINVAL;
2216
2217 }
2218
2219 static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_threshold = {
2220         .attr   = { .ca_owner = THIS_MODULE,
2221                     .ca_name = "dead_threshold",
2222                     .ca_mode = S_IRUGO | S_IWUSR },
2223         .show   = o2hb_heartbeat_group_threshold_show,
2224         .store  = o2hb_heartbeat_group_threshold_store,
2225 };
2226
2227 static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_mode = {
2228         .attr   = { .ca_owner = THIS_MODULE,
2229                 .ca_name = "mode",
2230                 .ca_mode = S_IRUGO | S_IWUSR },
2231         .show   = o2hb_heartbeat_group_mode_show,
2232         .store  = o2hb_heartbeat_group_mode_store,
2233 };
2234
2235 static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
2236         &o2hb_heartbeat_group_attr_threshold.attr,
2237         &o2hb_heartbeat_group_attr_mode.attr,
2238         NULL,
2239 };
2240
2241 static struct configfs_item_operations o2hb_heartbeat_group_item_ops = {
2242         .show_attribute         = o2hb_heartbeat_group_show,
2243         .store_attribute        = o2hb_heartbeat_group_store,
2244 };
2245
2246 static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
2247         .make_item      = o2hb_heartbeat_group_make_item,
2248         .drop_item      = o2hb_heartbeat_group_drop_item,
2249 };
2250
2251 static struct config_item_type o2hb_heartbeat_group_type = {
2252         .ct_group_ops   = &o2hb_heartbeat_group_group_ops,
2253         .ct_item_ops    = &o2hb_heartbeat_group_item_ops,
2254         .ct_attrs       = o2hb_heartbeat_group_attrs,
2255         .ct_owner       = THIS_MODULE,
2256 };
2257
2258 /* this is just here to avoid touching group in heartbeat.h which the
2259  * entire damn world #includes */
2260 struct config_group *o2hb_alloc_hb_set(void)
2261 {
2262         struct o2hb_heartbeat_group *hs = NULL;
2263         struct config_group *ret = NULL;
2264
2265         hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
2266         if (hs == NULL)
2267                 goto out;
2268
2269         config_group_init_type_name(&hs->hs_group, "heartbeat",
2270                                     &o2hb_heartbeat_group_type);
2271
2272         ret = &hs->hs_group;
2273 out:
2274         if (ret == NULL)
2275                 kfree(hs);
2276         return ret;
2277 }
2278
2279 void o2hb_free_hb_set(struct config_group *group)
2280 {
2281         struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
2282         kfree(hs);
2283 }
2284
2285 /* hb callback registration and issuing */
2286
2287 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
2288 {
2289         if (type == O2HB_NUM_CB)
2290                 return ERR_PTR(-EINVAL);
2291
2292         return &o2hb_callbacks[type];
2293 }
2294
2295 void o2hb_setup_callback(struct o2hb_callback_func *hc,
2296                          enum o2hb_callback_type type,
2297                          o2hb_cb_func *func,
2298                          void *data,
2299                          int priority)
2300 {
2301         INIT_LIST_HEAD(&hc->hc_item);
2302         hc->hc_func = func;
2303         hc->hc_data = data;
2304         hc->hc_priority = priority;
2305         hc->hc_type = type;
2306         hc->hc_magic = O2HB_CB_MAGIC;
2307 }
2308 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
2309
2310 /*
2311  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2312  * In global heartbeat mode, region_uuid passed is NULL.
2313  *
2314  * In local, we only pin the matching region. In global we pin all the active
2315  * regions.
2316  */
2317 static int o2hb_region_pin(const char *region_uuid)
2318 {
2319         int ret = 0, found = 0;
2320         struct o2hb_region *reg;
2321         char *uuid;
2322
2323         assert_spin_locked(&o2hb_live_lock);
2324
2325         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2326                 if (reg->hr_item_dropped)
2327                         continue;
2328
2329                 uuid = config_item_name(&reg->hr_item);
2330
2331                 /* local heartbeat */
2332                 if (region_uuid) {
2333                         if (strcmp(region_uuid, uuid))
2334                                 continue;
2335                         found = 1;
2336                 }
2337
2338                 if (reg->hr_item_pinned || reg->hr_item_dropped)
2339                         goto skip_pin;
2340
2341                 /* Ignore ENOENT only for local hb (userdlm domain) */
2342                 ret = o2nm_depend_item(&reg->hr_item);
2343                 if (!ret) {
2344                         mlog(ML_CLUSTER, "Pin region %s\n", uuid);
2345                         reg->hr_item_pinned = 1;
2346                 } else {
2347                         if (ret == -ENOENT && found)
2348                                 ret = 0;
2349                         else {
2350                                 mlog(ML_ERROR, "Pin region %s fails with %d\n",
2351                                      uuid, ret);
2352                                 break;
2353                         }
2354                 }
2355 skip_pin:
2356                 if (found)
2357                         break;
2358         }
2359
2360         return ret;
2361 }
2362
2363 /*
2364  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2365  * In global heartbeat mode, region_uuid passed is NULL.
2366  *
2367  * In local, we only unpin the matching region. In global we unpin all the
2368  * active regions.
2369  */
2370 static void o2hb_region_unpin(const char *region_uuid)
2371 {
2372         struct o2hb_region *reg;
2373         char *uuid;
2374         int found = 0;
2375
2376         assert_spin_locked(&o2hb_live_lock);
2377
2378         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2379                 if (reg->hr_item_dropped)
2380                         continue;
2381
2382                 uuid = config_item_name(&reg->hr_item);
2383                 if (region_uuid) {
2384                         if (strcmp(region_uuid, uuid))
2385                                 continue;
2386                         found = 1;
2387                 }
2388
2389                 if (reg->hr_item_pinned) {
2390                         mlog(ML_CLUSTER, "Unpin region %s\n", uuid);
2391                         o2nm_undepend_item(&reg->hr_item);
2392                         reg->hr_item_pinned = 0;
2393                 }
2394                 if (found)
2395                         break;
2396         }
2397 }
2398
2399 static int o2hb_region_inc_user(const char *region_uuid)
2400 {
2401         int ret = 0;
2402
2403         spin_lock(&o2hb_live_lock);
2404
2405         /* local heartbeat */
2406         if (!o2hb_global_heartbeat_active()) {
2407             ret = o2hb_region_pin(region_uuid);
2408             goto unlock;
2409         }
2410
2411         /*
2412          * if global heartbeat active and this is the first dependent user,
2413          * pin all regions if quorum region count <= CUT_OFF
2414          */
2415         o2hb_dependent_users++;
2416         if (o2hb_dependent_users > 1)
2417                 goto unlock;
2418
2419         if (bitmap_weight(o2hb_quorum_region_bitmap,
2420                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2421                 ret = o2hb_region_pin(NULL);
2422
2423 unlock:
2424         spin_unlock(&o2hb_live_lock);
2425         return ret;
2426 }
2427
2428 void o2hb_region_dec_user(const char *region_uuid)
2429 {
2430         spin_lock(&o2hb_live_lock);
2431
2432         /* local heartbeat */
2433         if (!o2hb_global_heartbeat_active()) {
2434             o2hb_region_unpin(region_uuid);
2435             goto unlock;
2436         }
2437
2438         /*
2439          * if global heartbeat active and there are no dependent users,
2440          * unpin all quorum regions
2441          */
2442         o2hb_dependent_users--;
2443         if (!o2hb_dependent_users)
2444                 o2hb_region_unpin(NULL);
2445
2446 unlock:
2447         spin_unlock(&o2hb_live_lock);
2448 }
2449
2450 int o2hb_register_callback(const char *region_uuid,
2451                            struct o2hb_callback_func *hc)
2452 {
2453         struct o2hb_callback_func *f;
2454         struct o2hb_callback *hbcall;
2455         int ret;
2456
2457         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2458         BUG_ON(!list_empty(&hc->hc_item));
2459
2460         hbcall = hbcall_from_type(hc->hc_type);
2461         if (IS_ERR(hbcall)) {
2462                 ret = PTR_ERR(hbcall);
2463                 goto out;
2464         }
2465
2466         if (region_uuid) {
2467                 ret = o2hb_region_inc_user(region_uuid);
2468                 if (ret) {
2469                         mlog_errno(ret);
2470                         goto out;
2471                 }
2472         }
2473
2474         down_write(&o2hb_callback_sem);
2475
2476         list_for_each_entry(f, &hbcall->list, hc_item) {
2477                 if (hc->hc_priority < f->hc_priority) {
2478                         list_add_tail(&hc->hc_item, &f->hc_item);
2479                         break;
2480                 }
2481         }
2482         if (list_empty(&hc->hc_item))
2483                 list_add_tail(&hc->hc_item, &hbcall->list);
2484
2485         up_write(&o2hb_callback_sem);
2486         ret = 0;
2487 out:
2488         mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
2489              ret, __builtin_return_address(0), hc);
2490         return ret;
2491 }
2492 EXPORT_SYMBOL_GPL(o2hb_register_callback);
2493
2494 void o2hb_unregister_callback(const char *region_uuid,
2495                               struct o2hb_callback_func *hc)
2496 {
2497         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2498
2499         mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
2500              __builtin_return_address(0), hc);
2501
2502         /* XXX Can this happen _with_ a region reference? */
2503         if (list_empty(&hc->hc_item))
2504                 return;
2505
2506         if (region_uuid)
2507                 o2hb_region_dec_user(region_uuid);
2508
2509         down_write(&o2hb_callback_sem);
2510
2511         list_del_init(&hc->hc_item);
2512
2513         up_write(&o2hb_callback_sem);
2514 }
2515 EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
2516
2517 int o2hb_check_node_heartbeating(u8 node_num)
2518 {
2519         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2520
2521         o2hb_fill_node_map(testing_map, sizeof(testing_map));
2522         if (!test_bit(node_num, testing_map)) {
2523                 mlog(ML_HEARTBEAT,
2524                      "node (%u) does not have heartbeating enabled.\n",
2525                      node_num);
2526                 return 0;
2527         }
2528
2529         return 1;
2530 }
2531 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating);
2532
2533 int o2hb_check_node_heartbeating_no_sem(u8 node_num)
2534 {
2535         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2536         unsigned long flags;
2537
2538         spin_lock_irqsave(&o2hb_live_lock, flags);
2539         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2540         spin_unlock_irqrestore(&o2hb_live_lock, flags);
2541         if (!test_bit(node_num, testing_map)) {
2542                 mlog(ML_HEARTBEAT,
2543                      "node (%u) does not have heartbeating enabled.\n",
2544                      node_num);
2545                 return 0;
2546         }
2547
2548         return 1;
2549 }
2550 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_no_sem);
2551
2552 int o2hb_check_node_heartbeating_from_callback(u8 node_num)
2553 {
2554         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2555
2556         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2557         if (!test_bit(node_num, testing_map)) {
2558                 mlog(ML_HEARTBEAT,
2559                      "node (%u) does not have heartbeating enabled.\n",
2560                      node_num);
2561                 return 0;
2562         }
2563
2564         return 1;
2565 }
2566 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_from_callback);
2567
2568 /* Makes sure our local node is configured with a node number, and is
2569  * heartbeating. */
2570 int o2hb_check_local_node_heartbeating(void)
2571 {
2572         u8 node_num;
2573
2574         /* if this node was set then we have networking */
2575         node_num = o2nm_this_node();
2576         if (node_num == O2NM_MAX_NODES) {
2577                 mlog(ML_HEARTBEAT, "this node has not been configured.\n");
2578                 return 0;
2579         }
2580
2581         return o2hb_check_node_heartbeating(node_num);
2582 }
2583 EXPORT_SYMBOL_GPL(o2hb_check_local_node_heartbeating);
2584
2585 /*
2586  * this is just a hack until we get the plumbing which flips file systems
2587  * read only and drops the hb ref instead of killing the node dead.
2588  */
2589 void o2hb_stop_all_regions(void)
2590 {
2591         struct o2hb_region *reg;
2592
2593         mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");
2594
2595         spin_lock(&o2hb_live_lock);
2596
2597         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
2598                 reg->hr_unclean_stop = 1;
2599
2600         spin_unlock(&o2hb_live_lock);
2601 }
2602 EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
2603
2604 int o2hb_get_all_regions(char *region_uuids, u8 max_regions)
2605 {
2606         struct o2hb_region *reg;
2607         int numregs = 0;
2608         char *p;
2609
2610         spin_lock(&o2hb_live_lock);
2611
2612         p = region_uuids;
2613         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2614                 if (reg->hr_item_dropped)
2615                         continue;
2616
2617                 mlog(0, "Region: %s\n", config_item_name(&reg->hr_item));
2618                 if (numregs < max_regions) {
2619                         memcpy(p, config_item_name(&reg->hr_item),
2620                                O2HB_MAX_REGION_NAME_LEN);
2621                         p += O2HB_MAX_REGION_NAME_LEN;
2622                 }
2623                 numregs++;
2624         }
2625
2626         spin_unlock(&o2hb_live_lock);
2627
2628         return numregs;
2629 }
2630 EXPORT_SYMBOL_GPL(o2hb_get_all_regions);
2631
2632 int o2hb_global_heartbeat_active(void)
2633 {
2634         return (o2hb_heartbeat_mode == O2HB_HEARTBEAT_GLOBAL);
2635 }
2636 EXPORT_SYMBOL(o2hb_global_heartbeat_active);