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
  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 /* Subtract b from a, storing the result in a. a *must* have a larger
1064  * value than b. */
1065 static void o2hb_tv_subtract(struct timeval *a,
1066                              struct timeval *b)
1067 {
1068         /* just return 0 when a is after b */
1069         if (a->tv_sec < b->tv_sec ||
1070             (a->tv_sec == b->tv_sec && a->tv_usec < b->tv_usec)) {
1071                 a->tv_sec = 0;
1072                 a->tv_usec = 0;
1073                 return;
1074         }
1075
1076         a->tv_sec -= b->tv_sec;
1077         a->tv_usec -= b->tv_usec;
1078         while ( a->tv_usec < 0 ) {
1079                 a->tv_sec--;
1080                 a->tv_usec += 1000000;
1081         }
1082 }
1083
1084 static unsigned int o2hb_elapsed_msecs(struct timeval *start,
1085                                        struct timeval *end)
1086 {
1087         struct timeval res = *end;
1088
1089         o2hb_tv_subtract(&res, start);
1090
1091         return res.tv_sec * 1000 + res.tv_usec / 1000;
1092 }
1093
1094 /*
1095  * we ride the region ref that the region dir holds.  before the region
1096  * dir is removed and drops it ref it will wait to tear down this
1097  * thread.
1098  */
1099 static int o2hb_thread(void *data)
1100 {
1101         int i, ret;
1102         struct o2hb_region *reg = data;
1103         struct o2hb_bio_wait_ctxt write_wc;
1104         struct timeval before_hb, after_hb;
1105         unsigned int elapsed_msec;
1106
1107         mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n");
1108
1109         set_user_nice(current, MIN_NICE);
1110
1111         /* Pin node */
1112         o2nm_depend_this_node();
1113
1114         while (!kthread_should_stop() &&
1115                !reg->hr_unclean_stop && !reg->hr_aborted_start) {
1116                 /* We track the time spent inside
1117                  * o2hb_do_disk_heartbeat so that we avoid more than
1118                  * hr_timeout_ms between disk writes. On busy systems
1119                  * this should result in a heartbeat which is less
1120                  * likely to time itself out. */
1121                 do_gettimeofday(&before_hb);
1122
1123                 ret = o2hb_do_disk_heartbeat(reg);
1124
1125                 do_gettimeofday(&after_hb);
1126                 elapsed_msec = o2hb_elapsed_msecs(&before_hb, &after_hb);
1127
1128                 mlog(ML_HEARTBEAT,
1129                      "start = %lu.%lu, end = %lu.%lu, msec = %u, ret = %d\n",
1130                      before_hb.tv_sec, (unsigned long) before_hb.tv_usec,
1131                      after_hb.tv_sec, (unsigned long) after_hb.tv_usec,
1132                      elapsed_msec, ret);
1133
1134                 if (!kthread_should_stop() &&
1135                     elapsed_msec < reg->hr_timeout_ms) {
1136                         /* the kthread api has blocked signals for us so no
1137                          * need to record the return value. */
1138                         msleep_interruptible(reg->hr_timeout_ms - elapsed_msec);
1139                 }
1140         }
1141
1142         o2hb_disarm_write_timeout(reg);
1143
1144         /* unclean stop is only used in very bad situation */
1145         for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
1146                 o2hb_shutdown_slot(&reg->hr_slots[i]);
1147
1148         /* Explicit down notification - avoid forcing the other nodes
1149          * to timeout on this region when we could just as easily
1150          * write a clear generation - thus indicating to them that
1151          * this node has left this region.
1152          */
1153         if (!reg->hr_unclean_stop && !reg->hr_aborted_start) {
1154                 o2hb_prepare_block(reg, 0);
1155                 ret = o2hb_issue_node_write(reg, &write_wc);
1156                 if (ret == 0)
1157                         o2hb_wait_on_io(reg, &write_wc);
1158                 else
1159                         mlog_errno(ret);
1160         }
1161
1162         /* Unpin node */
1163         o2nm_undepend_this_node();
1164
1165         mlog(ML_HEARTBEAT|ML_KTHREAD, "o2hb thread exiting\n");
1166
1167         return 0;
1168 }
1169
1170 #ifdef CONFIG_DEBUG_FS
1171 static int o2hb_debug_open(struct inode *inode, struct file *file)
1172 {
1173         struct o2hb_debug_buf *db = inode->i_private;
1174         struct o2hb_region *reg;
1175         unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1176         unsigned long lts;
1177         char *buf = NULL;
1178         int i = -1;
1179         int out = 0;
1180
1181         /* max_nodes should be the largest bitmap we pass here */
1182         BUG_ON(sizeof(map) < db->db_size);
1183
1184         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1185         if (!buf)
1186                 goto bail;
1187
1188         switch (db->db_type) {
1189         case O2HB_DB_TYPE_LIVENODES:
1190         case O2HB_DB_TYPE_LIVEREGIONS:
1191         case O2HB_DB_TYPE_QUORUMREGIONS:
1192         case O2HB_DB_TYPE_FAILEDREGIONS:
1193                 spin_lock(&o2hb_live_lock);
1194                 memcpy(map, db->db_data, db->db_size);
1195                 spin_unlock(&o2hb_live_lock);
1196                 break;
1197
1198         case O2HB_DB_TYPE_REGION_LIVENODES:
1199                 spin_lock(&o2hb_live_lock);
1200                 reg = (struct o2hb_region *)db->db_data;
1201                 memcpy(map, reg->hr_live_node_bitmap, db->db_size);
1202                 spin_unlock(&o2hb_live_lock);
1203                 break;
1204
1205         case O2HB_DB_TYPE_REGION_NUMBER:
1206                 reg = (struct o2hb_region *)db->db_data;
1207                 out += snprintf(buf + out, PAGE_SIZE - out, "%d\n",
1208                                 reg->hr_region_num);
1209                 goto done;
1210
1211         case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
1212                 reg = (struct o2hb_region *)db->db_data;
1213                 lts = reg->hr_last_timeout_start;
1214                 /* If 0, it has never been set before */
1215                 if (lts)
1216                         lts = jiffies_to_msecs(jiffies - lts);
1217                 out += snprintf(buf + out, PAGE_SIZE - out, "%lu\n", lts);
1218                 goto done;
1219
1220         case O2HB_DB_TYPE_REGION_PINNED:
1221                 reg = (struct o2hb_region *)db->db_data;
1222                 out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
1223                                 !!reg->hr_item_pinned);
1224                 goto done;
1225
1226         default:
1227                 goto done;
1228         }
1229
1230         while ((i = find_next_bit(map, db->db_len, i + 1)) < db->db_len)
1231                 out += snprintf(buf + out, PAGE_SIZE - out, "%d ", i);
1232         out += snprintf(buf + out, PAGE_SIZE - out, "\n");
1233
1234 done:
1235         i_size_write(inode, out);
1236
1237         file->private_data = buf;
1238
1239         return 0;
1240 bail:
1241         return -ENOMEM;
1242 }
1243
1244 static int o2hb_debug_release(struct inode *inode, struct file *file)
1245 {
1246         kfree(file->private_data);
1247         return 0;
1248 }
1249
1250 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1251                                  size_t nbytes, loff_t *ppos)
1252 {
1253         return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
1254                                        i_size_read(file->f_mapping->host));
1255 }
1256 #else
1257 static int o2hb_debug_open(struct inode *inode, struct file *file)
1258 {
1259         return 0;
1260 }
1261 static int o2hb_debug_release(struct inode *inode, struct file *file)
1262 {
1263         return 0;
1264 }
1265 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1266                                size_t nbytes, loff_t *ppos)
1267 {
1268         return 0;
1269 }
1270 #endif  /* CONFIG_DEBUG_FS */
1271
1272 static const struct file_operations o2hb_debug_fops = {
1273         .open =         o2hb_debug_open,
1274         .release =      o2hb_debug_release,
1275         .read =         o2hb_debug_read,
1276         .llseek =       generic_file_llseek,
1277 };
1278
1279 void o2hb_exit(void)
1280 {
1281         kfree(o2hb_db_livenodes);
1282         kfree(o2hb_db_liveregions);
1283         kfree(o2hb_db_quorumregions);
1284         kfree(o2hb_db_failedregions);
1285         debugfs_remove(o2hb_debug_failedregions);
1286         debugfs_remove(o2hb_debug_quorumregions);
1287         debugfs_remove(o2hb_debug_liveregions);
1288         debugfs_remove(o2hb_debug_livenodes);
1289         debugfs_remove(o2hb_debug_dir);
1290 }
1291
1292 static struct dentry *o2hb_debug_create(const char *name, struct dentry *dir,
1293                                         struct o2hb_debug_buf **db, int db_len,
1294                                         int type, int size, int len, void *data)
1295 {
1296         *db = kmalloc(db_len, GFP_KERNEL);
1297         if (!*db)
1298                 return NULL;
1299
1300         (*db)->db_type = type;
1301         (*db)->db_size = size;
1302         (*db)->db_len = len;
1303         (*db)->db_data = data;
1304
1305         return debugfs_create_file(name, S_IFREG|S_IRUSR, dir, *db,
1306                                    &o2hb_debug_fops);
1307 }
1308
1309 static int o2hb_debug_init(void)
1310 {
1311         int ret = -ENOMEM;
1312
1313         o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
1314         if (!o2hb_debug_dir) {
1315                 mlog_errno(ret);
1316                 goto bail;
1317         }
1318
1319         o2hb_debug_livenodes = o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1320                                                  o2hb_debug_dir,
1321                                                  &o2hb_db_livenodes,
1322                                                  sizeof(*o2hb_db_livenodes),
1323                                                  O2HB_DB_TYPE_LIVENODES,
1324                                                  sizeof(o2hb_live_node_bitmap),
1325                                                  O2NM_MAX_NODES,
1326                                                  o2hb_live_node_bitmap);
1327         if (!o2hb_debug_livenodes) {
1328                 mlog_errno(ret);
1329                 goto bail;
1330         }
1331
1332         o2hb_debug_liveregions = o2hb_debug_create(O2HB_DEBUG_LIVEREGIONS,
1333                                                    o2hb_debug_dir,
1334                                                    &o2hb_db_liveregions,
1335                                                    sizeof(*o2hb_db_liveregions),
1336                                                    O2HB_DB_TYPE_LIVEREGIONS,
1337                                                    sizeof(o2hb_live_region_bitmap),
1338                                                    O2NM_MAX_REGIONS,
1339                                                    o2hb_live_region_bitmap);
1340         if (!o2hb_debug_liveregions) {
1341                 mlog_errno(ret);
1342                 goto bail;
1343         }
1344
1345         o2hb_debug_quorumregions =
1346                         o2hb_debug_create(O2HB_DEBUG_QUORUMREGIONS,
1347                                           o2hb_debug_dir,
1348                                           &o2hb_db_quorumregions,
1349                                           sizeof(*o2hb_db_quorumregions),
1350                                           O2HB_DB_TYPE_QUORUMREGIONS,
1351                                           sizeof(o2hb_quorum_region_bitmap),
1352                                           O2NM_MAX_REGIONS,
1353                                           o2hb_quorum_region_bitmap);
1354         if (!o2hb_debug_quorumregions) {
1355                 mlog_errno(ret);
1356                 goto bail;
1357         }
1358
1359         o2hb_debug_failedregions =
1360                         o2hb_debug_create(O2HB_DEBUG_FAILEDREGIONS,
1361                                           o2hb_debug_dir,
1362                                           &o2hb_db_failedregions,
1363                                           sizeof(*o2hb_db_failedregions),
1364                                           O2HB_DB_TYPE_FAILEDREGIONS,
1365                                           sizeof(o2hb_failed_region_bitmap),
1366                                           O2NM_MAX_REGIONS,
1367                                           o2hb_failed_region_bitmap);
1368         if (!o2hb_debug_failedregions) {
1369                 mlog_errno(ret);
1370                 goto bail;
1371         }
1372
1373         ret = 0;
1374 bail:
1375         if (ret)
1376                 o2hb_exit();
1377
1378         return ret;
1379 }
1380
1381 int o2hb_init(void)
1382 {
1383         int i;
1384
1385         for (i = 0; i < ARRAY_SIZE(o2hb_callbacks); i++)
1386                 INIT_LIST_HEAD(&o2hb_callbacks[i].list);
1387
1388         for (i = 0; i < ARRAY_SIZE(o2hb_live_slots); i++)
1389                 INIT_LIST_HEAD(&o2hb_live_slots[i]);
1390
1391         INIT_LIST_HEAD(&o2hb_node_events);
1392
1393         memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
1394         memset(o2hb_region_bitmap, 0, sizeof(o2hb_region_bitmap));
1395         memset(o2hb_live_region_bitmap, 0, sizeof(o2hb_live_region_bitmap));
1396         memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
1397         memset(o2hb_failed_region_bitmap, 0, sizeof(o2hb_failed_region_bitmap));
1398
1399         o2hb_dependent_users = 0;
1400
1401         return o2hb_debug_init();
1402 }
1403
1404 /* if we're already in a callback then we're already serialized by the sem */
1405 static void o2hb_fill_node_map_from_callback(unsigned long *map,
1406                                              unsigned bytes)
1407 {
1408         BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1409
1410         memcpy(map, &o2hb_live_node_bitmap, bytes);
1411 }
1412
1413 /*
1414  * get a map of all nodes that are heartbeating in any regions
1415  */
1416 void o2hb_fill_node_map(unsigned long *map, unsigned bytes)
1417 {
1418         /* callers want to serialize this map and callbacks so that they
1419          * can trust that they don't miss nodes coming to the party */
1420         down_read(&o2hb_callback_sem);
1421         spin_lock(&o2hb_live_lock);
1422         o2hb_fill_node_map_from_callback(map, bytes);
1423         spin_unlock(&o2hb_live_lock);
1424         up_read(&o2hb_callback_sem);
1425 }
1426 EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
1427
1428 /*
1429  * heartbeat configfs bits.  The heartbeat set is a default set under
1430  * the cluster set in nodemanager.c.
1431  */
1432
1433 static struct o2hb_region *to_o2hb_region(struct config_item *item)
1434 {
1435         return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
1436 }
1437
1438 /* drop_item only drops its ref after killing the thread, nothing should
1439  * be using the region anymore.  this has to clean up any state that
1440  * attributes might have built up. */
1441 static void o2hb_region_release(struct config_item *item)
1442 {
1443         int i;
1444         struct page *page;
1445         struct o2hb_region *reg = to_o2hb_region(item);
1446
1447         mlog(ML_HEARTBEAT, "hb region release (%s)\n", reg->hr_dev_name);
1448
1449         kfree(reg->hr_tmp_block);
1450
1451         if (reg->hr_slot_data) {
1452                 for (i = 0; i < reg->hr_num_pages; i++) {
1453                         page = reg->hr_slot_data[i];
1454                         if (page)
1455                                 __free_page(page);
1456                 }
1457                 kfree(reg->hr_slot_data);
1458         }
1459
1460         if (reg->hr_bdev)
1461                 blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1462
1463         kfree(reg->hr_slots);
1464
1465         kfree(reg->hr_db_regnum);
1466         kfree(reg->hr_db_livenodes);
1467         debugfs_remove(reg->hr_debug_livenodes);
1468         debugfs_remove(reg->hr_debug_regnum);
1469         debugfs_remove(reg->hr_debug_elapsed_time);
1470         debugfs_remove(reg->hr_debug_pinned);
1471         debugfs_remove(reg->hr_debug_dir);
1472
1473         spin_lock(&o2hb_live_lock);
1474         list_del(&reg->hr_all_item);
1475         spin_unlock(&o2hb_live_lock);
1476
1477         kfree(reg);
1478 }
1479
1480 static int o2hb_read_block_input(struct o2hb_region *reg,
1481                                  const char *page,
1482                                  size_t count,
1483                                  unsigned long *ret_bytes,
1484                                  unsigned int *ret_bits)
1485 {
1486         unsigned long bytes;
1487         char *p = (char *)page;
1488
1489         bytes = simple_strtoul(p, &p, 0);
1490         if (!p || (*p && (*p != '\n')))
1491                 return -EINVAL;
1492
1493         /* Heartbeat and fs min / max block sizes are the same. */
1494         if (bytes > 4096 || bytes < 512)
1495                 return -ERANGE;
1496         if (hweight16(bytes) != 1)
1497                 return -EINVAL;
1498
1499         if (ret_bytes)
1500                 *ret_bytes = bytes;
1501         if (ret_bits)
1502                 *ret_bits = ffs(bytes) - 1;
1503
1504         return 0;
1505 }
1506
1507 static ssize_t o2hb_region_block_bytes_read(struct o2hb_region *reg,
1508                                             char *page)
1509 {
1510         return sprintf(page, "%u\n", reg->hr_block_bytes);
1511 }
1512
1513 static ssize_t o2hb_region_block_bytes_write(struct o2hb_region *reg,
1514                                              const char *page,
1515                                              size_t count)
1516 {
1517         int status;
1518         unsigned long block_bytes;
1519         unsigned int block_bits;
1520
1521         if (reg->hr_bdev)
1522                 return -EINVAL;
1523
1524         status = o2hb_read_block_input(reg, page, count,
1525                                        &block_bytes, &block_bits);
1526         if (status)
1527                 return status;
1528
1529         reg->hr_block_bytes = (unsigned int)block_bytes;
1530         reg->hr_block_bits = block_bits;
1531
1532         return count;
1533 }
1534
1535 static ssize_t o2hb_region_start_block_read(struct o2hb_region *reg,
1536                                             char *page)
1537 {
1538         return sprintf(page, "%llu\n", reg->hr_start_block);
1539 }
1540
1541 static ssize_t o2hb_region_start_block_write(struct o2hb_region *reg,
1542                                              const char *page,
1543                                              size_t count)
1544 {
1545         unsigned long long tmp;
1546         char *p = (char *)page;
1547
1548         if (reg->hr_bdev)
1549                 return -EINVAL;
1550
1551         tmp = simple_strtoull(p, &p, 0);
1552         if (!p || (*p && (*p != '\n')))
1553                 return -EINVAL;
1554
1555         reg->hr_start_block = tmp;
1556
1557         return count;
1558 }
1559
1560 static ssize_t o2hb_region_blocks_read(struct o2hb_region *reg,
1561                                        char *page)
1562 {
1563         return sprintf(page, "%d\n", reg->hr_blocks);
1564 }
1565
1566 static ssize_t o2hb_region_blocks_write(struct o2hb_region *reg,
1567                                         const char *page,
1568                                         size_t count)
1569 {
1570         unsigned long tmp;
1571         char *p = (char *)page;
1572
1573         if (reg->hr_bdev)
1574                 return -EINVAL;
1575
1576         tmp = simple_strtoul(p, &p, 0);
1577         if (!p || (*p && (*p != '\n')))
1578                 return -EINVAL;
1579
1580         if (tmp > O2NM_MAX_NODES || tmp == 0)
1581                 return -ERANGE;
1582
1583         reg->hr_blocks = (unsigned int)tmp;
1584
1585         return count;
1586 }
1587
1588 static ssize_t o2hb_region_dev_read(struct o2hb_region *reg,
1589                                     char *page)
1590 {
1591         unsigned int ret = 0;
1592
1593         if (reg->hr_bdev)
1594                 ret = sprintf(page, "%s\n", reg->hr_dev_name);
1595
1596         return ret;
1597 }
1598
1599 static void o2hb_init_region_params(struct o2hb_region *reg)
1600 {
1601         reg->hr_slots_per_page = PAGE_CACHE_SIZE >> reg->hr_block_bits;
1602         reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
1603
1604         mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
1605              reg->hr_start_block, reg->hr_blocks);
1606         mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
1607              reg->hr_block_bytes, reg->hr_block_bits);
1608         mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
1609         mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
1610 }
1611
1612 static int o2hb_map_slot_data(struct o2hb_region *reg)
1613 {
1614         int i, j;
1615         unsigned int last_slot;
1616         unsigned int spp = reg->hr_slots_per_page;
1617         struct page *page;
1618         char *raw;
1619         struct o2hb_disk_slot *slot;
1620
1621         reg->hr_tmp_block = kmalloc(reg->hr_block_bytes, GFP_KERNEL);
1622         if (reg->hr_tmp_block == NULL)
1623                 return -ENOMEM;
1624
1625         reg->hr_slots = kcalloc(reg->hr_blocks,
1626                                 sizeof(struct o2hb_disk_slot), GFP_KERNEL);
1627         if (reg->hr_slots == NULL)
1628                 return -ENOMEM;
1629
1630         for(i = 0; i < reg->hr_blocks; i++) {
1631                 slot = &reg->hr_slots[i];
1632                 slot->ds_node_num = i;
1633                 INIT_LIST_HEAD(&slot->ds_live_item);
1634                 slot->ds_raw_block = NULL;
1635         }
1636
1637         reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
1638         mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
1639                            "at %u blocks per page\n",
1640              reg->hr_num_pages, reg->hr_blocks, spp);
1641
1642         reg->hr_slot_data = kcalloc(reg->hr_num_pages, sizeof(struct page *),
1643                                     GFP_KERNEL);
1644         if (!reg->hr_slot_data)
1645                 return -ENOMEM;
1646
1647         for(i = 0; i < reg->hr_num_pages; i++) {
1648                 page = alloc_page(GFP_KERNEL);
1649                 if (!page)
1650                         return -ENOMEM;
1651
1652                 reg->hr_slot_data[i] = page;
1653
1654                 last_slot = i * spp;
1655                 raw = page_address(page);
1656                 for (j = 0;
1657                      (j < spp) && ((j + last_slot) < reg->hr_blocks);
1658                      j++) {
1659                         BUG_ON((j + last_slot) >= reg->hr_blocks);
1660
1661                         slot = &reg->hr_slots[j + last_slot];
1662                         slot->ds_raw_block =
1663                                 (struct o2hb_disk_heartbeat_block *) raw;
1664
1665                         raw += reg->hr_block_bytes;
1666                 }
1667         }
1668
1669         return 0;
1670 }
1671
1672 /* Read in all the slots available and populate the tracking
1673  * structures so that we can start with a baseline idea of what's
1674  * there. */
1675 static int o2hb_populate_slot_data(struct o2hb_region *reg)
1676 {
1677         int ret, i;
1678         struct o2hb_disk_slot *slot;
1679         struct o2hb_disk_heartbeat_block *hb_block;
1680
1681         ret = o2hb_read_slots(reg, reg->hr_blocks);
1682         if (ret)
1683                 goto out;
1684
1685         /* We only want to get an idea of the values initially in each
1686          * slot, so we do no verification - o2hb_check_slot will
1687          * actually determine if each configured slot is valid and
1688          * whether any values have changed. */
1689         for(i = 0; i < reg->hr_blocks; i++) {
1690                 slot = &reg->hr_slots[i];
1691                 hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
1692
1693                 /* Only fill the values that o2hb_check_slot uses to
1694                  * determine changing slots */
1695                 slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
1696                 slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
1697         }
1698
1699 out:
1700         return ret;
1701 }
1702
1703 /* this is acting as commit; we set up all of hr_bdev and hr_task or nothing */
1704 static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
1705                                      const char *page,
1706                                      size_t count)
1707 {
1708         struct task_struct *hb_task;
1709         long fd;
1710         int sectsize;
1711         char *p = (char *)page;
1712         struct fd f;
1713         struct inode *inode;
1714         ssize_t ret = -EINVAL;
1715         int live_threshold;
1716
1717         if (reg->hr_bdev)
1718                 goto out;
1719
1720         /* We can't heartbeat without having had our node number
1721          * configured yet. */
1722         if (o2nm_this_node() == O2NM_MAX_NODES)
1723                 goto out;
1724
1725         fd = simple_strtol(p, &p, 0);
1726         if (!p || (*p && (*p != '\n')))
1727                 goto out;
1728
1729         if (fd < 0 || fd >= INT_MAX)
1730                 goto out;
1731
1732         f = fdget(fd);
1733         if (f.file == NULL)
1734                 goto out;
1735
1736         if (reg->hr_blocks == 0 || reg->hr_start_block == 0 ||
1737             reg->hr_block_bytes == 0)
1738                 goto out2;
1739
1740         inode = igrab(f.file->f_mapping->host);
1741         if (inode == NULL)
1742                 goto out2;
1743
1744         if (!S_ISBLK(inode->i_mode))
1745                 goto out3;
1746
1747         reg->hr_bdev = I_BDEV(f.file->f_mapping->host);
1748         ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ, NULL);
1749         if (ret) {
1750                 reg->hr_bdev = NULL;
1751                 goto out3;
1752         }
1753         inode = NULL;
1754
1755         bdevname(reg->hr_bdev, reg->hr_dev_name);
1756
1757         sectsize = bdev_logical_block_size(reg->hr_bdev);
1758         if (sectsize != reg->hr_block_bytes) {
1759                 mlog(ML_ERROR,
1760                      "blocksize %u incorrect for device, expected %d",
1761                      reg->hr_block_bytes, sectsize);
1762                 ret = -EINVAL;
1763                 goto out3;
1764         }
1765
1766         o2hb_init_region_params(reg);
1767
1768         /* Generation of zero is invalid */
1769         do {
1770                 get_random_bytes(&reg->hr_generation,
1771                                  sizeof(reg->hr_generation));
1772         } while (reg->hr_generation == 0);
1773
1774         ret = o2hb_map_slot_data(reg);
1775         if (ret) {
1776                 mlog_errno(ret);
1777                 goto out3;
1778         }
1779
1780         ret = o2hb_populate_slot_data(reg);
1781         if (ret) {
1782                 mlog_errno(ret);
1783                 goto out3;
1784         }
1785
1786         INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
1787
1788         /*
1789          * A node is considered live after it has beat LIVE_THRESHOLD
1790          * times.  We're not steady until we've given them a chance
1791          * _after_ our first read.
1792          * The default threshold is bare minimum so as to limit the delay
1793          * during mounts. For global heartbeat, the threshold doubled for the
1794          * first region.
1795          */
1796         live_threshold = O2HB_LIVE_THRESHOLD;
1797         if (o2hb_global_heartbeat_active()) {
1798                 spin_lock(&o2hb_live_lock);
1799                 if (bitmap_weight(o2hb_region_bitmap, O2NM_MAX_REGIONS) == 1)
1800                         live_threshold <<= 1;
1801                 spin_unlock(&o2hb_live_lock);
1802         }
1803         ++live_threshold;
1804         atomic_set(&reg->hr_steady_iterations, live_threshold);
1805         /* unsteady_iterations is double the steady_iterations */
1806         atomic_set(&reg->hr_unsteady_iterations, (live_threshold << 1));
1807
1808         hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
1809                               reg->hr_item.ci_name);
1810         if (IS_ERR(hb_task)) {
1811                 ret = PTR_ERR(hb_task);
1812                 mlog_errno(ret);
1813                 goto out3;
1814         }
1815
1816         spin_lock(&o2hb_live_lock);
1817         reg->hr_task = hb_task;
1818         spin_unlock(&o2hb_live_lock);
1819
1820         ret = wait_event_interruptible(o2hb_steady_queue,
1821                                 atomic_read(&reg->hr_steady_iterations) == 0);
1822         if (ret) {
1823                 atomic_set(&reg->hr_steady_iterations, 0);
1824                 reg->hr_aborted_start = 1;
1825         }
1826
1827         if (reg->hr_aborted_start) {
1828                 ret = -EIO;
1829                 goto out3;
1830         }
1831
1832         /* Ok, we were woken.  Make sure it wasn't by drop_item() */
1833         spin_lock(&o2hb_live_lock);
1834         hb_task = reg->hr_task;
1835         if (o2hb_global_heartbeat_active())
1836                 set_bit(reg->hr_region_num, o2hb_live_region_bitmap);
1837         spin_unlock(&o2hb_live_lock);
1838
1839         if (hb_task)
1840                 ret = count;
1841         else
1842                 ret = -EIO;
1843
1844         if (hb_task && o2hb_global_heartbeat_active())
1845                 printk(KERN_NOTICE "o2hb: Heartbeat started on region %s (%s)\n",
1846                        config_item_name(&reg->hr_item), reg->hr_dev_name);
1847
1848 out3:
1849         iput(inode);
1850 out2:
1851         fdput(f);
1852 out:
1853         if (ret < 0) {
1854                 if (reg->hr_bdev) {
1855                         blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1856                         reg->hr_bdev = NULL;
1857                 }
1858         }
1859         return ret;
1860 }
1861
1862 static ssize_t o2hb_region_pid_read(struct o2hb_region *reg,
1863                                       char *page)
1864 {
1865         pid_t pid = 0;
1866
1867         spin_lock(&o2hb_live_lock);
1868         if (reg->hr_task)
1869                 pid = task_pid_nr(reg->hr_task);
1870         spin_unlock(&o2hb_live_lock);
1871
1872         if (!pid)
1873                 return 0;
1874
1875         return sprintf(page, "%u\n", pid);
1876 }
1877
1878 struct o2hb_region_attribute {
1879         struct configfs_attribute attr;
1880         ssize_t (*show)(struct o2hb_region *, char *);
1881         ssize_t (*store)(struct o2hb_region *, const char *, size_t);
1882 };
1883
1884 static struct o2hb_region_attribute o2hb_region_attr_block_bytes = {
1885         .attr   = { .ca_owner = THIS_MODULE,
1886                     .ca_name = "block_bytes",
1887                     .ca_mode = S_IRUGO | S_IWUSR },
1888         .show   = o2hb_region_block_bytes_read,
1889         .store  = o2hb_region_block_bytes_write,
1890 };
1891
1892 static struct o2hb_region_attribute o2hb_region_attr_start_block = {
1893         .attr   = { .ca_owner = THIS_MODULE,
1894                     .ca_name = "start_block",
1895                     .ca_mode = S_IRUGO | S_IWUSR },
1896         .show   = o2hb_region_start_block_read,
1897         .store  = o2hb_region_start_block_write,
1898 };
1899
1900 static struct o2hb_region_attribute o2hb_region_attr_blocks = {
1901         .attr   = { .ca_owner = THIS_MODULE,
1902                     .ca_name = "blocks",
1903                     .ca_mode = S_IRUGO | S_IWUSR },
1904         .show   = o2hb_region_blocks_read,
1905         .store  = o2hb_region_blocks_write,
1906 };
1907
1908 static struct o2hb_region_attribute o2hb_region_attr_dev = {
1909         .attr   = { .ca_owner = THIS_MODULE,
1910                     .ca_name = "dev",
1911                     .ca_mode = S_IRUGO | S_IWUSR },
1912         .show   = o2hb_region_dev_read,
1913         .store  = o2hb_region_dev_write,
1914 };
1915
1916 static struct o2hb_region_attribute o2hb_region_attr_pid = {
1917        .attr   = { .ca_owner = THIS_MODULE,
1918                    .ca_name = "pid",
1919                    .ca_mode = S_IRUGO | S_IRUSR },
1920        .show   = o2hb_region_pid_read,
1921 };
1922
1923 static struct configfs_attribute *o2hb_region_attrs[] = {
1924         &o2hb_region_attr_block_bytes.attr,
1925         &o2hb_region_attr_start_block.attr,
1926         &o2hb_region_attr_blocks.attr,
1927         &o2hb_region_attr_dev.attr,
1928         &o2hb_region_attr_pid.attr,
1929         NULL,
1930 };
1931
1932 static ssize_t o2hb_region_show(struct config_item *item,
1933                                 struct configfs_attribute *attr,
1934                                 char *page)
1935 {
1936         struct o2hb_region *reg = to_o2hb_region(item);
1937         struct o2hb_region_attribute *o2hb_region_attr =
1938                 container_of(attr, struct o2hb_region_attribute, attr);
1939         ssize_t ret = 0;
1940
1941         if (o2hb_region_attr->show)
1942                 ret = o2hb_region_attr->show(reg, page);
1943         return ret;
1944 }
1945
1946 static ssize_t o2hb_region_store(struct config_item *item,
1947                                  struct configfs_attribute *attr,
1948                                  const char *page, size_t count)
1949 {
1950         struct o2hb_region *reg = to_o2hb_region(item);
1951         struct o2hb_region_attribute *o2hb_region_attr =
1952                 container_of(attr, struct o2hb_region_attribute, attr);
1953         ssize_t ret = -EINVAL;
1954
1955         if (o2hb_region_attr->store)
1956                 ret = o2hb_region_attr->store(reg, page, count);
1957         return ret;
1958 }
1959
1960 static struct configfs_item_operations o2hb_region_item_ops = {
1961         .release                = o2hb_region_release,
1962         .show_attribute         = o2hb_region_show,
1963         .store_attribute        = o2hb_region_store,
1964 };
1965
1966 static struct config_item_type o2hb_region_type = {
1967         .ct_item_ops    = &o2hb_region_item_ops,
1968         .ct_attrs       = o2hb_region_attrs,
1969         .ct_owner       = THIS_MODULE,
1970 };
1971
1972 /* heartbeat set */
1973
1974 struct o2hb_heartbeat_group {
1975         struct config_group hs_group;
1976         /* some stuff? */
1977 };
1978
1979 static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
1980 {
1981         return group ?
1982                 container_of(group, struct o2hb_heartbeat_group, hs_group)
1983                 : NULL;
1984 }
1985
1986 static int o2hb_debug_region_init(struct o2hb_region *reg, struct dentry *dir)
1987 {
1988         int ret = -ENOMEM;
1989
1990         reg->hr_debug_dir =
1991                 debugfs_create_dir(config_item_name(&reg->hr_item), dir);
1992         if (!reg->hr_debug_dir) {
1993                 mlog_errno(ret);
1994                 goto bail;
1995         }
1996
1997         reg->hr_debug_livenodes =
1998                         o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1999                                           reg->hr_debug_dir,
2000                                           &(reg->hr_db_livenodes),
2001                                           sizeof(*(reg->hr_db_livenodes)),
2002                                           O2HB_DB_TYPE_REGION_LIVENODES,
2003                                           sizeof(reg->hr_live_node_bitmap),
2004                                           O2NM_MAX_NODES, reg);
2005         if (!reg->hr_debug_livenodes) {
2006                 mlog_errno(ret);
2007                 goto bail;
2008         }
2009
2010         reg->hr_debug_regnum =
2011                         o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER,
2012                                           reg->hr_debug_dir,
2013                                           &(reg->hr_db_regnum),
2014                                           sizeof(*(reg->hr_db_regnum)),
2015                                           O2HB_DB_TYPE_REGION_NUMBER,
2016                                           0, O2NM_MAX_NODES, reg);
2017         if (!reg->hr_debug_regnum) {
2018                 mlog_errno(ret);
2019                 goto bail;
2020         }
2021
2022         reg->hr_debug_elapsed_time =
2023                         o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME,
2024                                           reg->hr_debug_dir,
2025                                           &(reg->hr_db_elapsed_time),
2026                                           sizeof(*(reg->hr_db_elapsed_time)),
2027                                           O2HB_DB_TYPE_REGION_ELAPSED_TIME,
2028                                           0, 0, reg);
2029         if (!reg->hr_debug_elapsed_time) {
2030                 mlog_errno(ret);
2031                 goto bail;
2032         }
2033
2034         reg->hr_debug_pinned =
2035                         o2hb_debug_create(O2HB_DEBUG_REGION_PINNED,
2036                                           reg->hr_debug_dir,
2037                                           &(reg->hr_db_pinned),
2038                                           sizeof(*(reg->hr_db_pinned)),
2039                                           O2HB_DB_TYPE_REGION_PINNED,
2040                                           0, 0, reg);
2041         if (!reg->hr_debug_pinned) {
2042                 mlog_errno(ret);
2043                 goto bail;
2044         }
2045
2046         ret = 0;
2047 bail:
2048         return ret;
2049 }
2050
2051 static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
2052                                                           const char *name)
2053 {
2054         struct o2hb_region *reg = NULL;
2055         int ret;
2056
2057         reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
2058         if (reg == NULL)
2059                 return ERR_PTR(-ENOMEM);
2060
2061         if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
2062                 ret = -ENAMETOOLONG;
2063                 goto free;
2064         }
2065
2066         spin_lock(&o2hb_live_lock);
2067         reg->hr_region_num = 0;
2068         if (o2hb_global_heartbeat_active()) {
2069                 reg->hr_region_num = find_first_zero_bit(o2hb_region_bitmap,
2070                                                          O2NM_MAX_REGIONS);
2071                 if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
2072                         spin_unlock(&o2hb_live_lock);
2073                         ret = -EFBIG;
2074                         goto free;
2075                 }
2076                 set_bit(reg->hr_region_num, o2hb_region_bitmap);
2077         }
2078         list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
2079         spin_unlock(&o2hb_live_lock);
2080
2081         config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
2082
2083         ret = o2hb_debug_region_init(reg, o2hb_debug_dir);
2084         if (ret) {
2085                 config_item_put(&reg->hr_item);
2086                 goto free;
2087         }
2088
2089         return &reg->hr_item;
2090 free:
2091         kfree(reg);
2092         return ERR_PTR(ret);
2093 }
2094
2095 static void o2hb_heartbeat_group_drop_item(struct config_group *group,
2096                                            struct config_item *item)
2097 {
2098         struct task_struct *hb_task;
2099         struct o2hb_region *reg = to_o2hb_region(item);
2100         int quorum_region = 0;
2101
2102         /* stop the thread when the user removes the region dir */
2103         spin_lock(&o2hb_live_lock);
2104         hb_task = reg->hr_task;
2105         reg->hr_task = NULL;
2106         reg->hr_item_dropped = 1;
2107         spin_unlock(&o2hb_live_lock);
2108
2109         if (hb_task)
2110                 kthread_stop(hb_task);
2111
2112         if (o2hb_global_heartbeat_active()) {
2113                 spin_lock(&o2hb_live_lock);
2114                 clear_bit(reg->hr_region_num, o2hb_region_bitmap);
2115                 clear_bit(reg->hr_region_num, o2hb_live_region_bitmap);
2116                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
2117                         quorum_region = 1;
2118                 clear_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
2119                 spin_unlock(&o2hb_live_lock);
2120                 printk(KERN_NOTICE "o2hb: Heartbeat %s on region %s (%s)\n",
2121                        ((atomic_read(&reg->hr_steady_iterations) == 0) ?
2122                         "stopped" : "start aborted"), config_item_name(item),
2123                        reg->hr_dev_name);
2124         }
2125
2126         /*
2127          * If we're racing a dev_write(), we need to wake them.  They will
2128          * check reg->hr_task
2129          */
2130         if (atomic_read(&reg->hr_steady_iterations) != 0) {
2131                 reg->hr_aborted_start = 1;
2132                 atomic_set(&reg->hr_steady_iterations, 0);
2133                 wake_up(&o2hb_steady_queue);
2134         }
2135
2136         config_item_put(item);
2137
2138         if (!o2hb_global_heartbeat_active() || !quorum_region)
2139                 return;
2140
2141         /*
2142          * If global heartbeat active and there are dependent users,
2143          * pin all regions if quorum region count <= CUT_OFF
2144          */
2145         spin_lock(&o2hb_live_lock);
2146
2147         if (!o2hb_dependent_users)
2148                 goto unlock;
2149
2150         if (bitmap_weight(o2hb_quorum_region_bitmap,
2151                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2152                 o2hb_region_pin(NULL);
2153
2154 unlock:
2155         spin_unlock(&o2hb_live_lock);
2156 }
2157
2158 struct o2hb_heartbeat_group_attribute {
2159         struct configfs_attribute attr;
2160         ssize_t (*show)(struct o2hb_heartbeat_group *, char *);
2161         ssize_t (*store)(struct o2hb_heartbeat_group *, const char *, size_t);
2162 };
2163
2164 static ssize_t o2hb_heartbeat_group_show(struct config_item *item,
2165                                          struct configfs_attribute *attr,
2166                                          char *page)
2167 {
2168         struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
2169         struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
2170                 container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
2171         ssize_t ret = 0;
2172
2173         if (o2hb_heartbeat_group_attr->show)
2174                 ret = o2hb_heartbeat_group_attr->show(reg, page);
2175         return ret;
2176 }
2177
2178 static ssize_t o2hb_heartbeat_group_store(struct config_item *item,
2179                                           struct configfs_attribute *attr,
2180                                           const char *page, size_t count)
2181 {
2182         struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
2183         struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
2184                 container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
2185         ssize_t ret = -EINVAL;
2186
2187         if (o2hb_heartbeat_group_attr->store)
2188                 ret = o2hb_heartbeat_group_attr->store(reg, page, count);
2189         return ret;
2190 }
2191
2192 static ssize_t o2hb_heartbeat_group_threshold_show(struct o2hb_heartbeat_group *group,
2193                                                      char *page)
2194 {
2195         return sprintf(page, "%u\n", o2hb_dead_threshold);
2196 }
2197
2198 static ssize_t o2hb_heartbeat_group_threshold_store(struct o2hb_heartbeat_group *group,
2199                                                     const char *page,
2200                                                     size_t count)
2201 {
2202         unsigned long tmp;
2203         char *p = (char *)page;
2204
2205         tmp = simple_strtoul(p, &p, 10);
2206         if (!p || (*p && (*p != '\n')))
2207                 return -EINVAL;
2208
2209         /* this will validate ranges for us. */
2210         o2hb_dead_threshold_set((unsigned int) tmp);
2211
2212         return count;
2213 }
2214
2215 static
2216 ssize_t o2hb_heartbeat_group_mode_show(struct o2hb_heartbeat_group *group,
2217                                        char *page)
2218 {
2219         return sprintf(page, "%s\n",
2220                        o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
2221 }
2222
2223 static
2224 ssize_t o2hb_heartbeat_group_mode_store(struct o2hb_heartbeat_group *group,
2225                                         const char *page, size_t count)
2226 {
2227         unsigned int i;
2228         int ret;
2229         size_t len;
2230
2231         len = (page[count - 1] == '\n') ? count - 1 : count;
2232         if (!len)
2233                 return -EINVAL;
2234
2235         for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
2236                 if (strncasecmp(page, o2hb_heartbeat_mode_desc[i], len))
2237                         continue;
2238
2239                 ret = o2hb_global_heartbeat_mode_set(i);
2240                 if (!ret)
2241                         printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
2242                                o2hb_heartbeat_mode_desc[i]);
2243                 return count;
2244         }
2245
2246         return -EINVAL;
2247
2248 }
2249
2250 static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_threshold = {
2251         .attr   = { .ca_owner = THIS_MODULE,
2252                     .ca_name = "dead_threshold",
2253                     .ca_mode = S_IRUGO | S_IWUSR },
2254         .show   = o2hb_heartbeat_group_threshold_show,
2255         .store  = o2hb_heartbeat_group_threshold_store,
2256 };
2257
2258 static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_mode = {
2259         .attr   = { .ca_owner = THIS_MODULE,
2260                 .ca_name = "mode",
2261                 .ca_mode = S_IRUGO | S_IWUSR },
2262         .show   = o2hb_heartbeat_group_mode_show,
2263         .store  = o2hb_heartbeat_group_mode_store,
2264 };
2265
2266 static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
2267         &o2hb_heartbeat_group_attr_threshold.attr,
2268         &o2hb_heartbeat_group_attr_mode.attr,
2269         NULL,
2270 };
2271
2272 static struct configfs_item_operations o2hb_heartbeat_group_item_ops = {
2273         .show_attribute         = o2hb_heartbeat_group_show,
2274         .store_attribute        = o2hb_heartbeat_group_store,
2275 };
2276
2277 static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
2278         .make_item      = o2hb_heartbeat_group_make_item,
2279         .drop_item      = o2hb_heartbeat_group_drop_item,
2280 };
2281
2282 static struct config_item_type o2hb_heartbeat_group_type = {
2283         .ct_group_ops   = &o2hb_heartbeat_group_group_ops,
2284         .ct_item_ops    = &o2hb_heartbeat_group_item_ops,
2285         .ct_attrs       = o2hb_heartbeat_group_attrs,
2286         .ct_owner       = THIS_MODULE,
2287 };
2288
2289 /* this is just here to avoid touching group in heartbeat.h which the
2290  * entire damn world #includes */
2291 struct config_group *o2hb_alloc_hb_set(void)
2292 {
2293         struct o2hb_heartbeat_group *hs = NULL;
2294         struct config_group *ret = NULL;
2295
2296         hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
2297         if (hs == NULL)
2298                 goto out;
2299
2300         config_group_init_type_name(&hs->hs_group, "heartbeat",
2301                                     &o2hb_heartbeat_group_type);
2302
2303         ret = &hs->hs_group;
2304 out:
2305         if (ret == NULL)
2306                 kfree(hs);
2307         return ret;
2308 }
2309
2310 void o2hb_free_hb_set(struct config_group *group)
2311 {
2312         struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
2313         kfree(hs);
2314 }
2315
2316 /* hb callback registration and issuing */
2317
2318 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
2319 {
2320         if (type == O2HB_NUM_CB)
2321                 return ERR_PTR(-EINVAL);
2322
2323         return &o2hb_callbacks[type];
2324 }
2325
2326 void o2hb_setup_callback(struct o2hb_callback_func *hc,
2327                          enum o2hb_callback_type type,
2328                          o2hb_cb_func *func,
2329                          void *data,
2330                          int priority)
2331 {
2332         INIT_LIST_HEAD(&hc->hc_item);
2333         hc->hc_func = func;
2334         hc->hc_data = data;
2335         hc->hc_priority = priority;
2336         hc->hc_type = type;
2337         hc->hc_magic = O2HB_CB_MAGIC;
2338 }
2339 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
2340
2341 /*
2342  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2343  * In global heartbeat mode, region_uuid passed is NULL.
2344  *
2345  * In local, we only pin the matching region. In global we pin all the active
2346  * regions.
2347  */
2348 static int o2hb_region_pin(const char *region_uuid)
2349 {
2350         int ret = 0, found = 0;
2351         struct o2hb_region *reg;
2352         char *uuid;
2353
2354         assert_spin_locked(&o2hb_live_lock);
2355
2356         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2357                 if (reg->hr_item_dropped)
2358                         continue;
2359
2360                 uuid = config_item_name(&reg->hr_item);
2361
2362                 /* local heartbeat */
2363                 if (region_uuid) {
2364                         if (strcmp(region_uuid, uuid))
2365                                 continue;
2366                         found = 1;
2367                 }
2368
2369                 if (reg->hr_item_pinned || reg->hr_item_dropped)
2370                         goto skip_pin;
2371
2372                 /* Ignore ENOENT only for local hb (userdlm domain) */
2373                 ret = o2nm_depend_item(&reg->hr_item);
2374                 if (!ret) {
2375                         mlog(ML_CLUSTER, "Pin region %s\n", uuid);
2376                         reg->hr_item_pinned = 1;
2377                 } else {
2378                         if (ret == -ENOENT && found)
2379                                 ret = 0;
2380                         else {
2381                                 mlog(ML_ERROR, "Pin region %s fails with %d\n",
2382                                      uuid, ret);
2383                                 break;
2384                         }
2385                 }
2386 skip_pin:
2387                 if (found)
2388                         break;
2389         }
2390
2391         return ret;
2392 }
2393
2394 /*
2395  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2396  * In global heartbeat mode, region_uuid passed is NULL.
2397  *
2398  * In local, we only unpin the matching region. In global we unpin all the
2399  * active regions.
2400  */
2401 static void o2hb_region_unpin(const char *region_uuid)
2402 {
2403         struct o2hb_region *reg;
2404         char *uuid;
2405         int found = 0;
2406
2407         assert_spin_locked(&o2hb_live_lock);
2408
2409         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2410                 if (reg->hr_item_dropped)
2411                         continue;
2412
2413                 uuid = config_item_name(&reg->hr_item);
2414                 if (region_uuid) {
2415                         if (strcmp(region_uuid, uuid))
2416                                 continue;
2417                         found = 1;
2418                 }
2419
2420                 if (reg->hr_item_pinned) {
2421                         mlog(ML_CLUSTER, "Unpin region %s\n", uuid);
2422                         o2nm_undepend_item(&reg->hr_item);
2423                         reg->hr_item_pinned = 0;
2424                 }
2425                 if (found)
2426                         break;
2427         }
2428 }
2429
2430 static int o2hb_region_inc_user(const char *region_uuid)
2431 {
2432         int ret = 0;
2433
2434         spin_lock(&o2hb_live_lock);
2435
2436         /* local heartbeat */
2437         if (!o2hb_global_heartbeat_active()) {
2438             ret = o2hb_region_pin(region_uuid);
2439             goto unlock;
2440         }
2441
2442         /*
2443          * if global heartbeat active and this is the first dependent user,
2444          * pin all regions if quorum region count <= CUT_OFF
2445          */
2446         o2hb_dependent_users++;
2447         if (o2hb_dependent_users > 1)
2448                 goto unlock;
2449
2450         if (bitmap_weight(o2hb_quorum_region_bitmap,
2451                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2452                 ret = o2hb_region_pin(NULL);
2453
2454 unlock:
2455         spin_unlock(&o2hb_live_lock);
2456         return ret;
2457 }
2458
2459 void o2hb_region_dec_user(const char *region_uuid)
2460 {
2461         spin_lock(&o2hb_live_lock);
2462
2463         /* local heartbeat */
2464         if (!o2hb_global_heartbeat_active()) {
2465             o2hb_region_unpin(region_uuid);
2466             goto unlock;
2467         }
2468
2469         /*
2470          * if global heartbeat active and there are no dependent users,
2471          * unpin all quorum regions
2472          */
2473         o2hb_dependent_users--;
2474         if (!o2hb_dependent_users)
2475                 o2hb_region_unpin(NULL);
2476
2477 unlock:
2478         spin_unlock(&o2hb_live_lock);
2479 }
2480
2481 int o2hb_register_callback(const char *region_uuid,
2482                            struct o2hb_callback_func *hc)
2483 {
2484         struct o2hb_callback_func *f;
2485         struct o2hb_callback *hbcall;
2486         int ret;
2487
2488         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2489         BUG_ON(!list_empty(&hc->hc_item));
2490
2491         hbcall = hbcall_from_type(hc->hc_type);
2492         if (IS_ERR(hbcall)) {
2493                 ret = PTR_ERR(hbcall);
2494                 goto out;
2495         }
2496
2497         if (region_uuid) {
2498                 ret = o2hb_region_inc_user(region_uuid);
2499                 if (ret) {
2500                         mlog_errno(ret);
2501                         goto out;
2502                 }
2503         }
2504
2505         down_write(&o2hb_callback_sem);
2506
2507         list_for_each_entry(f, &hbcall->list, hc_item) {
2508                 if (hc->hc_priority < f->hc_priority) {
2509                         list_add_tail(&hc->hc_item, &f->hc_item);
2510                         break;
2511                 }
2512         }
2513         if (list_empty(&hc->hc_item))
2514                 list_add_tail(&hc->hc_item, &hbcall->list);
2515
2516         up_write(&o2hb_callback_sem);
2517         ret = 0;
2518 out:
2519         mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
2520              ret, __builtin_return_address(0), hc);
2521         return ret;
2522 }
2523 EXPORT_SYMBOL_GPL(o2hb_register_callback);
2524
2525 void o2hb_unregister_callback(const char *region_uuid,
2526                               struct o2hb_callback_func *hc)
2527 {
2528         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2529
2530         mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
2531              __builtin_return_address(0), hc);
2532
2533         /* XXX Can this happen _with_ a region reference? */
2534         if (list_empty(&hc->hc_item))
2535                 return;
2536
2537         if (region_uuid)
2538                 o2hb_region_dec_user(region_uuid);
2539
2540         down_write(&o2hb_callback_sem);
2541
2542         list_del_init(&hc->hc_item);
2543
2544         up_write(&o2hb_callback_sem);
2545 }
2546 EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
2547
2548 int o2hb_check_node_heartbeating(u8 node_num)
2549 {
2550         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2551
2552         o2hb_fill_node_map(testing_map, sizeof(testing_map));
2553         if (!test_bit(node_num, testing_map)) {
2554                 mlog(ML_HEARTBEAT,
2555                      "node (%u) does not have heartbeating enabled.\n",
2556                      node_num);
2557                 return 0;
2558         }
2559
2560         return 1;
2561 }
2562 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating);
2563
2564 int o2hb_check_node_heartbeating_no_sem(u8 node_num)
2565 {
2566         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2567         unsigned long flags;
2568
2569         spin_lock_irqsave(&o2hb_live_lock, flags);
2570         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2571         spin_unlock_irqrestore(&o2hb_live_lock, flags);
2572         if (!test_bit(node_num, testing_map)) {
2573                 mlog(ML_HEARTBEAT,
2574                      "node (%u) does not have heartbeating enabled.\n",
2575                      node_num);
2576                 return 0;
2577         }
2578
2579         return 1;
2580 }
2581 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_no_sem);
2582
2583 int o2hb_check_node_heartbeating_from_callback(u8 node_num)
2584 {
2585         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2586
2587         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2588         if (!test_bit(node_num, testing_map)) {
2589                 mlog(ML_HEARTBEAT,
2590                      "node (%u) does not have heartbeating enabled.\n",
2591                      node_num);
2592                 return 0;
2593         }
2594
2595         return 1;
2596 }
2597 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_from_callback);
2598
2599 /* Makes sure our local node is configured with a node number, and is
2600  * heartbeating. */
2601 int o2hb_check_local_node_heartbeating(void)
2602 {
2603         u8 node_num;
2604
2605         /* if this node was set then we have networking */
2606         node_num = o2nm_this_node();
2607         if (node_num == O2NM_MAX_NODES) {
2608                 mlog(ML_HEARTBEAT, "this node has not been configured.\n");
2609                 return 0;
2610         }
2611
2612         return o2hb_check_node_heartbeating(node_num);
2613 }
2614 EXPORT_SYMBOL_GPL(o2hb_check_local_node_heartbeating);
2615
2616 /*
2617  * this is just a hack until we get the plumbing which flips file systems
2618  * read only and drops the hb ref instead of killing the node dead.
2619  */
2620 void o2hb_stop_all_regions(void)
2621 {
2622         struct o2hb_region *reg;
2623
2624         mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");
2625
2626         spin_lock(&o2hb_live_lock);
2627
2628         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
2629                 reg->hr_unclean_stop = 1;
2630
2631         spin_unlock(&o2hb_live_lock);
2632 }
2633 EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
2634
2635 int o2hb_get_all_regions(char *region_uuids, u8 max_regions)
2636 {
2637         struct o2hb_region *reg;
2638         int numregs = 0;
2639         char *p;
2640
2641         spin_lock(&o2hb_live_lock);
2642
2643         p = region_uuids;
2644         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2645                 if (reg->hr_item_dropped)
2646                         continue;
2647
2648                 mlog(0, "Region: %s\n", config_item_name(&reg->hr_item));
2649                 if (numregs < max_regions) {
2650                         memcpy(p, config_item_name(&reg->hr_item),
2651                                O2HB_MAX_REGION_NAME_LEN);
2652                         p += O2HB_MAX_REGION_NAME_LEN;
2653                 }
2654                 numregs++;
2655         }
2656
2657         spin_unlock(&o2hb_live_lock);
2658
2659         return numregs;
2660 }
2661 EXPORT_SYMBOL_GPL(o2hb_get_all_regions);
2662
2663 int o2hb_global_heartbeat_active(void)
2664 {
2665         return (o2hb_heartbeat_mode == O2HB_HEARTBEAT_GLOBAL);
2666 }
2667 EXPORT_SYMBOL(o2hb_global_heartbeat_active);