fs/ocfs2/cluster/heartbeat.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2004, 2005 Oracle.  All rights reserved.
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/sched.h>
   8 #include <linux/jiffies.h>
   9 #include <linux/module.h>
  10 #include <linux/fs.h>
  11 #include <linux/bio.h>
  12 #include <linux/blkdev.h>
  13 #include <linux/delay.h>
  14 #include <linux/file.h>
  15 #include <linux/kthread.h>
  16 #include <linux/configfs.h>
  17 #include <linux/random.h>
  18 #include <linux/crc32.h>
  19 #include <linux/time.h>
  20 #include <linux/debugfs.h>
  21 #include <linux/slab.h>
  22 #include <linux/bitmap.h>
  23 #include <linux/ktime.h>
  24 #include "heartbeat.h"
  25 #include "tcp.h"
  26 #include "nodemanager.h"
  27 #include "quorum.h"
  28
  29 #include "masklog.h"
  30
  31
  32 /*
  33  * The first heartbeat pass had one global thread that would serialize all hb
  34  * callback calls.  This global serializing sem should only be removed once
  35  * we've made sure that all callees can deal with being called concurrently
  36  * from multiple hb region threads.
  37  */
  38 static DECLARE_RWSEM(o2hb_callback_sem);
  39
  40 /*
  41  * multiple hb threads are watching multiple regions.  A node is live
  42  * whenever any of the threads sees activity from the node in its region.
  43  */
  44 static DEFINE_SPINLOCK(o2hb_live_lock);
  45 static struct list_head o2hb_live_slots[O2NM_MAX_NODES];
  46 static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
  47 static LIST_HEAD(o2hb_node_events);
  48 static DECLARE_WAIT_QUEUE_HEAD(o2hb_steady_queue);
  49
  50 /*
  51  * In global heartbeat, we maintain a series of region bitmaps.
  52  *      - o2hb_region_bitmap allows us to limit the region number to max region.
  53  *      - o2hb_live_region_bitmap tracks live regions (seen steady iterations).
  54  *      - o2hb_quorum_region_bitmap tracks live regions that have seen all nodes
  55  *              heartbeat on it.
  56  *      - o2hb_failed_region_bitmap tracks the regions that have seen io timeouts.
  57  */
  58 static unsigned long o2hb_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  59 static unsigned long o2hb_live_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  60 static unsigned long o2hb_quorum_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  61 static unsigned long o2hb_failed_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  62
  63 #define O2HB_DB_TYPE_LIVENODES          0
  64 #define O2HB_DB_TYPE_LIVEREGIONS        1
  65 #define O2HB_DB_TYPE_QUORUMREGIONS      2
  66 #define O2HB_DB_TYPE_FAILEDREGIONS      3
  67 #define O2HB_DB_TYPE_REGION_LIVENODES   4
  68 #define O2HB_DB_TYPE_REGION_NUMBER      5
  69 #define O2HB_DB_TYPE_REGION_ELAPSED_TIME        6
  70 #define O2HB_DB_TYPE_REGION_PINNED      7
  71 struct o2hb_debug_buf {
  72         int db_type;
  73         int db_size;
  74         int db_len;
  75         void *db_data;
  76 };
  77
  78 static struct o2hb_debug_buf *o2hb_db_livenodes;
  79 static struct o2hb_debug_buf *o2hb_db_liveregions;
  80 static struct o2hb_debug_buf *o2hb_db_quorumregions;
  81 static struct o2hb_debug_buf *o2hb_db_failedregions;
  82
  83 #define O2HB_DEBUG_DIR                  "o2hb"
  84 #define O2HB_DEBUG_LIVENODES            "livenodes"
  85 #define O2HB_DEBUG_LIVEREGIONS          "live_regions"
  86 #define O2HB_DEBUG_QUORUMREGIONS        "quorum_regions"
  87 #define O2HB_DEBUG_FAILEDREGIONS        "failed_regions"
  88 #define O2HB_DEBUG_REGION_NUMBER        "num"
  89 #define O2HB_DEBUG_REGION_ELAPSED_TIME  "elapsed_time_in_ms"
  90 #define O2HB_DEBUG_REGION_PINNED        "pinned"
  91
  92 static struct dentry *o2hb_debug_dir;
  93
  94 static LIST_HEAD(o2hb_all_regions);
  95
  96 static struct o2hb_callback {
  97         struct list_head list;
  98 } o2hb_callbacks[O2HB_NUM_CB];
  99
 100 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type);
 101
 102 enum o2hb_heartbeat_modes {
 103         O2HB_HEARTBEAT_LOCAL            = 0,
 104         O2HB_HEARTBEAT_GLOBAL,
 105         O2HB_HEARTBEAT_NUM_MODES,
 106 };
 107
 108 static const char *o2hb_heartbeat_mode_desc[O2HB_HEARTBEAT_NUM_MODES] = {
 109         "local",        /* O2HB_HEARTBEAT_LOCAL */
 110         "global",       /* O2HB_HEARTBEAT_GLOBAL */
 111 };
 112
 113 unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
 114 static unsigned int o2hb_heartbeat_mode = O2HB_HEARTBEAT_LOCAL;
 115
 116 /*
 117  * o2hb_dependent_users tracks the number of registered callbacks that depend
 118  * on heartbeat. o2net and o2dlm are two entities that register this callback.
 119  * However only o2dlm depends on the heartbeat. It does not want the heartbeat
 120  * to stop while a dlm domain is still active.
 121  */
 122 static unsigned int o2hb_dependent_users;
 123
 124 /*
 125  * In global heartbeat mode, all regions are pinned if there are one or more
 126  * dependent users and the quorum region count is <= O2HB_PIN_CUT_OFF. All
 127  * regions are unpinned if the region count exceeds the cut off or the number
 128  * of dependent users falls to zero.
 129  */
 130 #define O2HB_PIN_CUT_OFF                3
 131
 132 /*
 133  * In local heartbeat mode, we assume the dlm domain name to be the same as
 134  * region uuid. This is true for domains created for the file system but not
 135  * necessarily true for userdlm domains. This is a known limitation.
 136  *
 137  * In global heartbeat mode, we pin/unpin all o2hb regions. This solution
 138  * works for both file system and userdlm domains.
 139  */
 140 static int o2hb_region_pin(const char *region_uuid);
 141 static void o2hb_region_unpin(const char *region_uuid);
 142
 143 /* Only sets a new threshold if there are no active regions.
 144  *
 145  * No locking or otherwise interesting code is required for reading
 146  * o2hb_dead_threshold as it can't change once regions are active and
 147  * it's not interesting to anyone until then anyway. */
 148 static void o2hb_dead_threshold_set(unsigned int threshold)
 149 {
 150         if (threshold > O2HB_MIN_DEAD_THRESHOLD) {
 151                 spin_lock(&o2hb_live_lock);
 152                 if (list_empty(&o2hb_all_regions))
 153                         o2hb_dead_threshold = threshold;
 154                 spin_unlock(&o2hb_live_lock);
 155         }
 156 }
 157
 158 static int o2hb_global_heartbeat_mode_set(unsigned int hb_mode)
 159 {
 160         int ret = -1;
 161
 162         if (hb_mode < O2HB_HEARTBEAT_NUM_MODES) {
 163                 spin_lock(&o2hb_live_lock);
 164                 if (list_empty(&o2hb_all_regions)) {
 165                         o2hb_heartbeat_mode = hb_mode;
 166                         ret = 0;
 167                 }
 168                 spin_unlock(&o2hb_live_lock);
 169         }
 170
 171         return ret;
 172 }
 173
 174 struct o2hb_node_event {
 175         struct list_head        hn_item;
 176         enum o2hb_callback_type hn_event_type;
 177         struct o2nm_node        *hn_node;
 178         int                     hn_node_num;
 179 };
 180
 181 struct o2hb_disk_slot {
 182         struct o2hb_disk_heartbeat_block *ds_raw_block;
 183         u8                      ds_node_num;
 184         u64                     ds_last_time;
 185         u64                     ds_last_generation;
 186         u16                     ds_equal_samples;
 187         u16                     ds_changed_samples;
 188         struct list_head        ds_live_item;
 189 };
 190
 191 /* each thread owns a region.. when we're asked to tear down the region
 192  * we ask the thread to stop, who cleans up the region */
 193 struct o2hb_region {
 194         struct config_item      hr_item;
 195
 196         struct list_head        hr_all_item;
 197         unsigned                hr_unclean_stop:1,
 198                                 hr_aborted_start:1,
 199                                 hr_item_pinned:1,
 200                                 hr_item_dropped:1,
 201                                 hr_node_deleted:1;
 202
 203         /* protected by the hr_callback_sem */
 204         struct task_struct      *hr_task;
 205
 206         unsigned int            hr_blocks;
 207         unsigned long long      hr_start_block;
 208
 209         unsigned int            hr_block_bits;
 210         unsigned int            hr_block_bytes;
 211
 212         unsigned int            hr_slots_per_page;
 213         unsigned int            hr_num_pages;
 214
 215         struct page             **hr_slot_data;
 216         struct file             *hr_bdev_file;
 217         struct o2hb_disk_slot   *hr_slots;
 218
 219         /* live node map of this region */
 220         unsigned long           hr_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 221         unsigned int            hr_region_num;
 222
 223         struct dentry           *hr_debug_dir;
 224         struct o2hb_debug_buf   *hr_db_livenodes;
 225         struct o2hb_debug_buf   *hr_db_regnum;
 226         struct o2hb_debug_buf   *hr_db_elapsed_time;
 227         struct o2hb_debug_buf   *hr_db_pinned;
 228
 229         /* let the person setting up hb wait for it to return until it
 230          * has reached a 'steady' state.  This will be fixed when we have
 231          * a more complete api that doesn't lead to this sort of fragility. */
 232         atomic_t                hr_steady_iterations;
 233
 234         /* terminate o2hb thread if it does not reach steady state
 235          * (hr_steady_iterations == 0) within hr_unsteady_iterations */
 236         atomic_t                hr_unsteady_iterations;
 237
 238         unsigned int            hr_timeout_ms;
 239
 240         /* randomized as the region goes up and down so that a node
 241          * recognizes a node going up and down in one iteration */
 242         u64                     hr_generation;
 243
 244         struct delayed_work     hr_write_timeout_work;
 245         unsigned long           hr_last_timeout_start;
 246
 247         /* negotiate timer, used to negotiate extending hb timeout. */
 248         struct delayed_work     hr_nego_timeout_work;
 249         unsigned long           hr_nego_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 250
 251         /* Used during o2hb_check_slot to hold a copy of the block
 252          * being checked because we temporarily have to zero out the
 253          * crc field. */
 254         struct o2hb_disk_heartbeat_block *hr_tmp_block;
 255
 256         /* Message key for negotiate timeout message. */
 257         unsigned int            hr_key;
 258         struct list_head        hr_handler_list;
 259
 260         /* last hb status, 0 for success, other value for error. */
 261         int                     hr_last_hb_status;
 262 };
 263
 264 static inline struct block_device *reg_bdev(struct o2hb_region *reg)
 265 {
 266         return reg->hr_bdev_file ? file_bdev(reg->hr_bdev_file) : NULL;
 267 }
 268
 269 struct o2hb_bio_wait_ctxt {
 270         atomic_t          wc_num_reqs;
 271         struct completion wc_io_complete;
 272         int               wc_error;
 273 };
 274
 275 #define O2HB_NEGO_TIMEOUT_MS (O2HB_MAX_WRITE_TIMEOUT_MS/2)
 276
 277 enum {
 278         O2HB_NEGO_TIMEOUT_MSG = 1,
 279         O2HB_NEGO_APPROVE_MSG = 2,
 280 };
 281
 282 struct o2hb_nego_msg {
 283         u8 node_num;
 284 };
 285
 286 static void o2hb_write_timeout(struct work_struct *work)
 287 {
 288         int failed, quorum;
 289         struct o2hb_region *reg =
 290                 container_of(work, struct o2hb_region,
 291                              hr_write_timeout_work.work);
 292
 293         mlog(ML_ERROR, "Heartbeat write timeout to device %pg after %u "
 294              "milliseconds\n", reg_bdev(reg),
 295              jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
 296
 297         if (o2hb_global_heartbeat_active()) {
 298                 spin_lock(&o2hb_live_lock);
 299                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 300                         set_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 301                 failed = bitmap_weight(o2hb_failed_region_bitmap,
 302                                         O2NM_MAX_REGIONS);
 303                 quorum = bitmap_weight(o2hb_quorum_region_bitmap,
 304                                         O2NM_MAX_REGIONS);
 305                 spin_unlock(&o2hb_live_lock);
 306
 307                 mlog(ML_HEARTBEAT, "Number of regions %d, failed regions %d\n",
 308                      quorum, failed);
 309
 310                 /*
 311                  * Fence if the number of failed regions >= half the number
 312                  * of  quorum regions
 313                  */
 314                 if ((failed << 1) < quorum)
 315                         return;
 316         }
 317
 318         o2quo_disk_timeout();
 319 }
 320
 321 static void o2hb_arm_timeout(struct o2hb_region *reg)
 322 {
 323         /* Arm writeout only after thread reaches steady state */
 324         if (atomic_read(&reg->hr_steady_iterations) != 0)
 325                 return;
 326
 327         mlog(ML_HEARTBEAT, "Queue write timeout for %u ms\n",
 328              O2HB_MAX_WRITE_TIMEOUT_MS);
 329
 330         if (o2hb_global_heartbeat_active()) {
 331                 spin_lock(&o2hb_live_lock);
 332                 clear_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 333                 spin_unlock(&o2hb_live_lock);
 334         }
 335         cancel_delayed_work(&reg->hr_write_timeout_work);
 336         schedule_delayed_work(&reg->hr_write_timeout_work,
 337                               msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
 338
 339         cancel_delayed_work(&reg->hr_nego_timeout_work);
 340         /* negotiate timeout must be less than write timeout. */
 341         schedule_delayed_work(&reg->hr_nego_timeout_work,
 342                               msecs_to_jiffies(O2HB_NEGO_TIMEOUT_MS));
 343         bitmap_zero(reg->hr_nego_node_bitmap, O2NM_MAX_NODES);
 344 }
 345
 346 static void o2hb_disarm_timeout(struct o2hb_region *reg)
 347 {
 348         cancel_delayed_work_sync(&reg->hr_write_timeout_work);
 349         cancel_delayed_work_sync(&reg->hr_nego_timeout_work);
 350 }
 351
 352 static int o2hb_send_nego_msg(int key, int type, u8 target)
 353 {
 354         struct o2hb_nego_msg msg;
 355         int status, ret;
 356
 357         msg.node_num = o2nm_this_node();
 358 again:
 359         ret = o2net_send_message(type, key, &msg, sizeof(msg),
 360                         target, &status);
 361
 362         if (ret == -EAGAIN || ret == -ENOMEM) {
 363                 msleep(100);
 364                 goto again;
 365         }
 366
 367         return ret;
 368 }
 369
 370 static void o2hb_nego_timeout(struct work_struct *work)
 371 {
 372         unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 373         int master_node, i, ret;
 374         struct o2hb_region *reg;
 375
 376         reg = container_of(work, struct o2hb_region, hr_nego_timeout_work.work);
 377         /* don't negotiate timeout if last hb failed since it is very
 378          * possible io failed. Should let write timeout fence self.
 379          */
 380         if (reg->hr_last_hb_status)
 381                 return;
 382
 383         o2hb_fill_node_map(live_node_bitmap, O2NM_MAX_NODES);
 384         /* lowest node as master node to make negotiate decision. */
 385         master_node = find_first_bit(live_node_bitmap, O2NM_MAX_NODES);
 386
 387         if (master_node == o2nm_this_node()) {
 388                 if (!test_bit(master_node, reg->hr_nego_node_bitmap)) {
 389                         printk(KERN_NOTICE "o2hb: node %d hb write hung for %ds on region %s (%pg).\n",
 390                                 o2nm_this_node(), O2HB_NEGO_TIMEOUT_MS/1000,
 391                                 config_item_name(&reg->hr_item), reg_bdev(reg));
 392                         set_bit(master_node, reg->hr_nego_node_bitmap);
 393                 }
 394                 if (!bitmap_equal(reg->hr_nego_node_bitmap, live_node_bitmap,
 395                                   O2NM_MAX_NODES)) {
 396                         /* check negotiate bitmap every second to do timeout
 397                          * approve decision.
 398                          */
 399                         schedule_delayed_work(&reg->hr_nego_timeout_work,
 400                                 msecs_to_jiffies(1000));
 401
 402                         return;
 403                 }
 404
 405                 printk(KERN_NOTICE "o2hb: all nodes hb write hung, maybe region %s (%pg) is down.\n",
 406                         config_item_name(&reg->hr_item),
 407                         reg_bdev(reg));
 408                 /* approve negotiate timeout request. */
 409                 o2hb_arm_timeout(reg);
 410
 411                 i = -1;
 412                 while ((i = find_next_bit(live_node_bitmap,
 413                                 O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
 414                         if (i == master_node)
 415                                 continue;
 416
 417                         mlog(ML_HEARTBEAT, "send NEGO_APPROVE msg to node %d\n", i);
 418                         ret = o2hb_send_nego_msg(reg->hr_key,
 419                                         O2HB_NEGO_APPROVE_MSG, i);
 420                         if (ret)
 421                                 mlog(ML_ERROR, "send NEGO_APPROVE msg to node %d fail %d\n",
 422                                         i, ret);
 423                 }
 424         } else {
 425                 /* negotiate timeout with master node. */
 426                 printk(KERN_NOTICE "o2hb: node %d hb write hung for %ds on region %s (%pg), negotiate timeout with node %d.\n",
 427                         o2nm_this_node(), O2HB_NEGO_TIMEOUT_MS/1000, config_item_name(&reg->hr_item),
 428                         reg_bdev(reg), master_node);
 429                 ret = o2hb_send_nego_msg(reg->hr_key, O2HB_NEGO_TIMEOUT_MSG,
 430                                 master_node);
 431                 if (ret)
 432                         mlog(ML_ERROR, "send NEGO_TIMEOUT msg to node %d fail %d\n",
 433                                 master_node, ret);
 434         }
 435 }
 436
 437 static int o2hb_nego_timeout_handler(struct o2net_msg *msg, u32 len, void *data,
 438                                 void **ret_data)
 439 {
 440         struct o2hb_region *reg = data;
 441         struct o2hb_nego_msg *nego_msg;
 442
 443         nego_msg = (struct o2hb_nego_msg *)msg->buf;
 444         printk(KERN_NOTICE "o2hb: receive negotiate timeout message from node %d on region %s (%pg).\n",
 445                 nego_msg->node_num, config_item_name(&reg->hr_item),
 446                 reg_bdev(reg));
 447         if (nego_msg->node_num < O2NM_MAX_NODES)
 448                 set_bit(nego_msg->node_num, reg->hr_nego_node_bitmap);
 449         else
 450                 mlog(ML_ERROR, "got nego timeout message from bad node.\n");
 451
 452         return 0;
 453 }
 454
 455 static int o2hb_nego_approve_handler(struct o2net_msg *msg, u32 len, void *data,
 456                                 void **ret_data)
 457 {
 458         struct o2hb_region *reg = data;
 459
 460         printk(KERN_NOTICE "o2hb: negotiate timeout approved by master node on region %s (%pg).\n",
 461                 config_item_name(&reg->hr_item), reg_bdev(reg));
 462         o2hb_arm_timeout(reg);
 463         return 0;
 464 }
 465
 466 static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
 467 {
 468         atomic_set(&wc->wc_num_reqs, 1);
 469         init_completion(&wc->wc_io_complete);
 470         wc->wc_error = 0;
 471 }
 472
 473 /* Used in error paths too */
 474 static inline void o2hb_bio_wait_dec(struct o2hb_bio_wait_ctxt *wc,
 475                                      unsigned int num)
 476 {
 477         /* sadly atomic_sub_and_test() isn't available on all platforms.  The
 478          * good news is that the fast path only completes one at a time */
 479         while(num--) {
 480                 if (atomic_dec_and_test(&wc->wc_num_reqs)) {
 481                         BUG_ON(num > 0);
 482                         complete(&wc->wc_io_complete);
 483                 }
 484         }
 485 }
 486
 487 static void o2hb_wait_on_io(struct o2hb_bio_wait_ctxt *wc)
 488 {
 489         o2hb_bio_wait_dec(wc, 1);
 490         wait_for_completion(&wc->wc_io_complete);
 491 }
 492
 493 static void o2hb_bio_end_io(struct bio *bio)
 494 {
 495         struct o2hb_bio_wait_ctxt *wc = bio->bi_private;
 496
 497         if (bio->bi_status) {
 498                 mlog(ML_ERROR, "IO Error %d\n", bio->bi_status);
 499                 wc->wc_error = blk_status_to_errno(bio->bi_status);
 500         }
 501
 502         o2hb_bio_wait_dec(wc, 1);
 503         bio_put(bio);
 504 }
 505
 506 /* Setup a Bio to cover I/O against num_slots slots starting at
 507  * start_slot. */
 508 static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
 509                                       struct o2hb_bio_wait_ctxt *wc,
 510                                       unsigned int *current_slot,
 511                                       unsigned int max_slots, blk_opf_t opf)
 512 {
 513         int len, current_page;
 514         unsigned int vec_len, vec_start;
 515         unsigned int bits = reg->hr_block_bits;
 516         unsigned int spp = reg->hr_slots_per_page;
 517         unsigned int cs = *current_slot;
 518         struct bio *bio;
 519         struct page *page;
 520
 521         /* Testing has shown this allocation to take long enough under
 522          * GFP_KERNEL that the local node can get fenced. It would be
 523          * nicest if we could pre-allocate these bios and avoid this
 524          * all together. */
 525         bio = bio_alloc(reg_bdev(reg), 16, opf, GFP_ATOMIC);
 526         if (!bio) {
 527                 mlog(ML_ERROR, "Could not alloc slots BIO!\n");
 528                 bio = ERR_PTR(-ENOMEM);
 529                 goto bail;
 530         }
 531
 532         /* Must put everything in 512 byte sectors for the bio... */
 533         bio->bi_iter.bi_sector = (reg->hr_start_block + cs) << (bits - 9);
 534         bio->bi_private = wc;
 535         bio->bi_end_io = o2hb_bio_end_io;
 536
 537         vec_start = (cs << bits) % PAGE_SIZE;
 538         while(cs < max_slots) {
 539                 current_page = cs / spp;
 540                 page = reg->hr_slot_data[current_page];
 541
 542                 vec_len = min(PAGE_SIZE - vec_start,
 543                               (max_slots-cs) * (PAGE_SIZE/spp) );
 544
 545                 mlog(ML_HB_BIO, "page %d, vec_len = %u, vec_start = %u\n",
 546                      current_page, vec_len, vec_start);
 547
 548                 len = bio_add_page(bio, page, vec_len, vec_start);
 549                 if (len != vec_len) break;
 550
 551                 cs += vec_len / (PAGE_SIZE/spp);
 552                 vec_start = 0;
 553         }
 554
 555 bail:
 556         *current_slot = cs;
 557         return bio;
 558 }
 559
 560 static int o2hb_read_slots(struct o2hb_region *reg,
 561                            unsigned int begin_slot,
 562                            unsigned int max_slots)
 563 {
 564         unsigned int current_slot = begin_slot;
 565         int status;
 566         struct o2hb_bio_wait_ctxt wc;
 567         struct bio *bio;
 568
 569         o2hb_bio_wait_init(&wc);
 570
 571         while(current_slot < max_slots) {
 572                 bio = o2hb_setup_one_bio(reg, &wc, &current_slot, max_slots,
 573                                          REQ_OP_READ);
 574                 if (IS_ERR(bio)) {
 575                         status = PTR_ERR(bio);
 576                         mlog_errno(status);
 577                         goto bail_and_wait;
 578                 }
 579
 580                 atomic_inc(&wc.wc_num_reqs);
 581                 submit_bio(bio);
 582         }
 583
 584         status = 0;
 585
 586 bail_and_wait:
 587         o2hb_wait_on_io(&wc);
 588         if (wc.wc_error && !status)
 589                 status = wc.wc_error;
 590
 591         return status;
 592 }
 593
 594 static int o2hb_issue_node_write(struct o2hb_region *reg,
 595                                  struct o2hb_bio_wait_ctxt *write_wc)
 596 {
 597         int status;
 598         unsigned int slot;
 599         struct bio *bio;
 600
 601         o2hb_bio_wait_init(write_wc);
 602
 603         slot = o2nm_this_node();
 604
 605         bio = o2hb_setup_one_bio(reg, write_wc, &slot, slot+1,
 606                                  REQ_OP_WRITE | REQ_SYNC);
 607         if (IS_ERR(bio)) {
 608                 status = PTR_ERR(bio);
 609                 mlog_errno(status);
 610                 goto bail;
 611         }
 612
 613         atomic_inc(&write_wc->wc_num_reqs);
 614         submit_bio(bio);
 615
 616         status = 0;
 617 bail:
 618         return status;
 619 }
 620
 621 static u32 o2hb_compute_block_crc_le(struct o2hb_region *reg,
 622                                      struct o2hb_disk_heartbeat_block *hb_block)
 623 {
 624         __le32 old_cksum;
 625         u32 ret;
 626
 627         /* We want to compute the block crc with a 0 value in the
 628          * hb_cksum field. Save it off here and replace after the
 629          * crc. */
 630         old_cksum = hb_block->hb_cksum;
 631         hb_block->hb_cksum = 0;
 632
 633         ret = crc32_le(0, (unsigned char *) hb_block, reg->hr_block_bytes);
 634
 635         hb_block->hb_cksum = old_cksum;
 636
 637         return ret;
 638 }
 639
 640 static void o2hb_dump_slot(struct o2hb_disk_heartbeat_block *hb_block)
 641 {
 642         mlog(ML_ERROR, "Dump slot information: seq = 0x%llx, node = %u, "
 643              "cksum = 0x%x, generation 0x%llx\n",
 644              (long long)le64_to_cpu(hb_block->hb_seq),
 645              hb_block->hb_node, le32_to_cpu(hb_block->hb_cksum),
 646              (long long)le64_to_cpu(hb_block->hb_generation));
 647 }
 648
 649 static int o2hb_verify_crc(struct o2hb_region *reg,
 650                            struct o2hb_disk_heartbeat_block *hb_block)
 651 {
 652         u32 read, computed;
 653
 654         read = le32_to_cpu(hb_block->hb_cksum);
 655         computed = o2hb_compute_block_crc_le(reg, hb_block);
 656
 657         return read == computed;
 658 }
 659
 660 /*
 661  * Compare the slot data with what we wrote in the last iteration.
 662  * If the match fails, print an appropriate error message. This is to
 663  * detect errors like... another node hearting on the same slot,
 664  * flaky device that is losing writes, etc.
 665  * Returns 1 if check succeeds, 0 otherwise.
 666  */
 667 static int o2hb_check_own_slot(struct o2hb_region *reg)
 668 {
 669         struct o2hb_disk_slot *slot;
 670         struct o2hb_disk_heartbeat_block *hb_block;
 671         char *errstr;
 672
 673         slot = &reg->hr_slots[o2nm_this_node()];
 674         /* Don't check on our 1st timestamp */
 675         if (!slot->ds_last_time)
 676                 return 0;
 677
 678         hb_block = slot->ds_raw_block;
 679         if (le64_to_cpu(hb_block->hb_seq) == slot->ds_last_time &&
 680             le64_to_cpu(hb_block->hb_generation) == slot->ds_last_generation &&
 681             hb_block->hb_node == slot->ds_node_num)
 682                 return 1;
 683
 684 #define ERRSTR1         "Another node is heartbeating on device"
 685 #define ERRSTR2         "Heartbeat generation mismatch on device"
 686 #define ERRSTR3         "Heartbeat sequence mismatch on device"
 687
 688         if (hb_block->hb_node != slot->ds_node_num)
 689                 errstr = ERRSTR1;
 690         else if (le64_to_cpu(hb_block->hb_generation) !=
 691                  slot->ds_last_generation)
 692                 errstr = ERRSTR2;
 693         else
 694                 errstr = ERRSTR3;
 695
 696         mlog(ML_ERROR, "%s (%pg): expected(%u:0x%llx, 0x%llx), "
 697              "ondisk(%u:0x%llx, 0x%llx)\n", errstr, reg_bdev(reg),
 698              slot->ds_node_num, (unsigned long long)slot->ds_last_generation,
 699              (unsigned long long)slot->ds_last_time, hb_block->hb_node,
 700              (unsigned long long)le64_to_cpu(hb_block->hb_generation),
 701              (unsigned long long)le64_to_cpu(hb_block->hb_seq));
 702
 703         return 0;
 704 }
 705
 706 static inline void o2hb_prepare_block(struct o2hb_region *reg,
 707                                       u64 generation)
 708 {
 709         int node_num;
 710         u64 cputime;
 711         struct o2hb_disk_slot *slot;
 712         struct o2hb_disk_heartbeat_block *hb_block;
 713
 714         node_num = o2nm_this_node();
 715         slot = &reg->hr_slots[node_num];
 716
 717         hb_block = (struct o2hb_disk_heartbeat_block *)slot->ds_raw_block;
 718         memset(hb_block, 0, reg->hr_block_bytes);
 719         /* TODO: time stuff */
 720         cputime = ktime_get_real_seconds();
 721         if (!cputime)
 722                 cputime = 1;
 723
 724         hb_block->hb_seq = cpu_to_le64(cputime);
 725         hb_block->hb_node = node_num;
 726         hb_block->hb_generation = cpu_to_le64(generation);
 727         hb_block->hb_dead_ms = cpu_to_le32(o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS);
 728
 729         /* This step must always happen last! */
 730         hb_block->hb_cksum = cpu_to_le32(o2hb_compute_block_crc_le(reg,
 731                                                                    hb_block));
 732
 733         mlog(ML_HB_BIO, "our node generation = 0x%llx, cksum = 0x%x\n",
 734              (long long)generation,
 735              le32_to_cpu(hb_block->hb_cksum));
 736 }
 737
 738 static void o2hb_fire_callbacks(struct o2hb_callback *hbcall,
 739                                 struct o2nm_node *node,
 740                                 int idx)
 741 {
 742         struct o2hb_callback_func *f;
 743
 744         list_for_each_entry(f, &hbcall->list, hc_item) {
 745                 mlog(ML_HEARTBEAT, "calling funcs %p\n", f);
 746                 (f->hc_func)(node, idx, f->hc_data);
 747         }
 748 }
 749
 750 /* Will run the list in order until we process the passed event */
 751 static void o2hb_run_event_list(struct o2hb_node_event *queued_event)
 752 {
 753         struct o2hb_callback *hbcall;
 754         struct o2hb_node_event *event;
 755
 756         /* Holding callback sem assures we don't alter the callback
 757          * lists when doing this, and serializes ourselves with other
 758          * processes wanting callbacks. */
 759         down_write(&o2hb_callback_sem);
 760
 761         spin_lock(&o2hb_live_lock);
 762         while (!list_empty(&o2hb_node_events)
 763                && !list_empty(&queued_event->hn_item)) {
 764                 event = list_entry(o2hb_node_events.next,
 765                                    struct o2hb_node_event,
 766                                    hn_item);
 767                 list_del_init(&event->hn_item);
 768                 spin_unlock(&o2hb_live_lock);
 769
 770                 mlog(ML_HEARTBEAT, "Node %s event for %d\n",
 771                      event->hn_event_type == O2HB_NODE_UP_CB ? "UP" : "DOWN",
 772                      event->hn_node_num);
 773
 774                 hbcall = hbcall_from_type(event->hn_event_type);
 775
 776                 /* We should *never* have gotten on to the list with a
 777                  * bad type... This isn't something that we should try
 778                  * to recover from. */
 779                 BUG_ON(IS_ERR(hbcall));
 780
 781                 o2hb_fire_callbacks(hbcall, event->hn_node, event->hn_node_num);
 782
 783                 spin_lock(&o2hb_live_lock);
 784         }
 785         spin_unlock(&o2hb_live_lock);
 786
 787         up_write(&o2hb_callback_sem);
 788 }
 789
 790 static void o2hb_queue_node_event(struct o2hb_node_event *event,
 791                                   enum o2hb_callback_type type,
 792                                   struct o2nm_node *node,
 793                                   int node_num)
 794 {
 795         assert_spin_locked(&o2hb_live_lock);
 796
 797         BUG_ON((!node) && (type != O2HB_NODE_DOWN_CB));
 798
 799         event->hn_event_type = type;
 800         event->hn_node = node;
 801         event->hn_node_num = node_num;
 802
 803         mlog(ML_HEARTBEAT, "Queue node %s event for node %d\n",
 804              type == O2HB_NODE_UP_CB ? "UP" : "DOWN", node_num);
 805
 806         list_add_tail(&event->hn_item, &o2hb_node_events);
 807 }
 808
 809 static void o2hb_shutdown_slot(struct o2hb_disk_slot *slot)
 810 {
 811         struct o2hb_node_event event =
 812                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 813         struct o2nm_node *node;
 814         int queued = 0;
 815
 816         node = o2nm_get_node_by_num(slot->ds_node_num);
 817         if (!node)
 818                 return;
 819
 820         spin_lock(&o2hb_live_lock);
 821         if (!list_empty(&slot->ds_live_item)) {
 822                 mlog(ML_HEARTBEAT, "Shutdown, node %d leaves region\n",
 823                      slot->ds_node_num);
 824
 825                 list_del_init(&slot->ds_live_item);
 826
 827                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 828                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 829
 830                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB, node,
 831                                               slot->ds_node_num);
 832                         queued = 1;
 833                 }
 834         }
 835         spin_unlock(&o2hb_live_lock);
 836
 837         if (queued)
 838                 o2hb_run_event_list(&event);
 839
 840         o2nm_node_put(node);
 841 }
 842
 843 static void o2hb_set_quorum_device(struct o2hb_region *reg)
 844 {
 845         if (!o2hb_global_heartbeat_active())
 846                 return;
 847
 848         /* Prevent race with o2hb_heartbeat_group_drop_item() */
 849         if (kthread_should_stop())
 850                 return;
 851
 852         /* Tag region as quorum only after thread reaches steady state */
 853         if (atomic_read(&reg->hr_steady_iterations) != 0)
 854                 return;
 855
 856         spin_lock(&o2hb_live_lock);
 857
 858         if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 859                 goto unlock;
 860
 861         /*
 862          * A region can be added to the quorum only when it sees all
 863          * live nodes heartbeat on it. In other words, the region has been
 864          * added to all nodes.
 865          */
 866         if (!bitmap_equal(reg->hr_live_node_bitmap, o2hb_live_node_bitmap,
 867                           O2NM_MAX_NODES))
 868                 goto unlock;
 869
 870         printk(KERN_NOTICE "o2hb: Region %s (%pg) is now a quorum device\n",
 871                config_item_name(&reg->hr_item), reg_bdev(reg));
 872
 873         set_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
 874
 875         /*
 876          * If global heartbeat active, unpin all regions if the
 877          * region count > CUT_OFF
 878          */
 879         if (bitmap_weight(o2hb_quorum_region_bitmap,
 880                            O2NM_MAX_REGIONS) > O2HB_PIN_CUT_OFF)
 881                 o2hb_region_unpin(NULL);
 882 unlock:
 883         spin_unlock(&o2hb_live_lock);
 884 }
 885
 886 static int o2hb_check_slot(struct o2hb_region *reg,
 887                            struct o2hb_disk_slot *slot)
 888 {
 889         int changed = 0, gen_changed = 0;
 890         struct o2hb_node_event event =
 891                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 892         struct o2nm_node *node;
 893         struct o2hb_disk_heartbeat_block *hb_block = reg->hr_tmp_block;
 894         u64 cputime;
 895         unsigned int dead_ms = o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS;
 896         unsigned int slot_dead_ms;
 897         int tmp;
 898         int queued = 0;
 899
 900         memcpy(hb_block, slot->ds_raw_block, reg->hr_block_bytes);
 901
 902         /*
 903          * If a node is no longer configured but is still in the livemap, we
 904          * may need to clear that bit from the livemap.
 905          */
 906         node = o2nm_get_node_by_num(slot->ds_node_num);
 907         if (!node) {
 908                 spin_lock(&o2hb_live_lock);
 909                 tmp = test_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 910                 spin_unlock(&o2hb_live_lock);
 911                 if (!tmp)
 912                         return 0;
 913         }
 914
 915         if (!o2hb_verify_crc(reg, hb_block)) {
 916                 /* all paths from here will drop o2hb_live_lock for
 917                  * us. */
 918                 spin_lock(&o2hb_live_lock);
 919
 920                 /* Don't print an error on the console in this case -
 921                  * a freshly formatted heartbeat area will not have a
 922                  * crc set on it. */
 923                 if (list_empty(&slot->ds_live_item))
 924                         goto out;
 925
 926                 /* The node is live but pushed out a bad crc. We
 927                  * consider it a transient miss but don't populate any
 928                  * other values as they may be junk. */
 929                 mlog(ML_ERROR, "Node %d has written a bad crc to %pg\n",
 930                      slot->ds_node_num, reg_bdev(reg));
 931                 o2hb_dump_slot(hb_block);
 932
 933                 slot->ds_equal_samples++;
 934                 goto fire_callbacks;
 935         }
 936
 937         /* we don't care if these wrap.. the state transitions below
 938          * clear at the right places */
 939         cputime = le64_to_cpu(hb_block->hb_seq);
 940         if (slot->ds_last_time != cputime)
 941                 slot->ds_changed_samples++;
 942         else
 943                 slot->ds_equal_samples++;
 944         slot->ds_last_time = cputime;
 945
 946         /* The node changed heartbeat generations. We assume this to
 947          * mean it dropped off but came back before we timed out. We
 948          * want to consider it down for the time being but don't want
 949          * to lose any changed_samples state we might build up to
 950          * considering it live again. */
 951         if (slot->ds_last_generation != le64_to_cpu(hb_block->hb_generation)) {
 952                 gen_changed = 1;
 953                 slot->ds_equal_samples = 0;
 954                 mlog(ML_HEARTBEAT, "Node %d changed generation (0x%llx "
 955                      "to 0x%llx)\n", slot->ds_node_num,
 956                      (long long)slot->ds_last_generation,
 957                      (long long)le64_to_cpu(hb_block->hb_generation));
 958         }
 959
 960         slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
 961
 962         mlog(ML_HEARTBEAT, "Slot %d gen 0x%llx cksum 0x%x "
 963              "seq %llu last %llu changed %u equal %u\n",
 964              slot->ds_node_num, (long long)slot->ds_last_generation,
 965              le32_to_cpu(hb_block->hb_cksum),
 966              (unsigned long long)le64_to_cpu(hb_block->hb_seq),
 967              (unsigned long long)slot->ds_last_time, slot->ds_changed_samples,
 968              slot->ds_equal_samples);
 969
 970         spin_lock(&o2hb_live_lock);
 971
 972 fire_callbacks:
 973         /* dead nodes only come to life after some number of
 974          * changes at any time during their dead time */
 975         if (list_empty(&slot->ds_live_item) &&
 976             slot->ds_changed_samples >= O2HB_LIVE_THRESHOLD) {
 977                 mlog(ML_HEARTBEAT, "Node %d (id 0x%llx) joined my region\n",
 978                      slot->ds_node_num, (long long)slot->ds_last_generation);
 979
 980                 set_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 981
 982                 /* first on the list generates a callback */
 983                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 984                         mlog(ML_HEARTBEAT, "o2hb: Add node %d to live nodes "
 985                              "bitmap\n", slot->ds_node_num);
 986                         set_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 987
 988                         o2hb_queue_node_event(&event, O2HB_NODE_UP_CB, node,
 989                                               slot->ds_node_num);
 990
 991                         changed = 1;
 992                         queued = 1;
 993                 }
 994
 995                 list_add_tail(&slot->ds_live_item,
 996                               &o2hb_live_slots[slot->ds_node_num]);
 997
 998                 slot->ds_equal_samples = 0;
 999
1000                 /* We want to be sure that all nodes agree on the
1001                  * number of milliseconds before a node will be
1002                  * considered dead. The self-fencing timeout is
1003                  * computed from this value, and a discrepancy might
1004                  * result in heartbeat calling a node dead when it
1005                  * hasn't self-fenced yet. */
1006                 slot_dead_ms = le32_to_cpu(hb_block->hb_dead_ms);
1007                 if (slot_dead_ms && slot_dead_ms != dead_ms) {
1008                         /* TODO: Perhaps we can fail the region here. */
1009                         mlog(ML_ERROR, "Node %d on device %pg has a dead count "
1010                              "of %u ms, but our count is %u ms.\n"
1011                              "Please double check your configuration values "
1012                              "for 'O2CB_HEARTBEAT_THRESHOLD'\n",
1013                              slot->ds_node_num, reg_bdev(reg),
1014                              slot_dead_ms, dead_ms);
1015                 }
1016                 goto out;
1017         }
1018
1019         /* if the list is dead, we're done.. */
1020         if (list_empty(&slot->ds_live_item))
1021                 goto out;
1022
1023         /* live nodes only go dead after enough consequtive missed
1024          * samples..  reset the missed counter whenever we see
1025          * activity */
1026         if (slot->ds_equal_samples >= o2hb_dead_threshold || gen_changed) {
1027                 mlog(ML_HEARTBEAT, "Node %d left my region\n",
1028                      slot->ds_node_num);
1029
1030                 clear_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
1031
1032                 /* last off the live_slot generates a callback */
1033                 list_del_init(&slot->ds_live_item);
1034                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
1035                         mlog(ML_HEARTBEAT, "o2hb: Remove node %d from live "
1036                              "nodes bitmap\n", slot->ds_node_num);
1037                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
1038
1039                         /* node can be null */
1040                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB,
1041                                               node, slot->ds_node_num);
1042
1043                         changed = 1;
1044                         queued = 1;
1045                 }
1046
1047                 /* We don't clear this because the node is still
1048                  * actually writing new blocks. */
1049                 if (!gen_changed)
1050                         slot->ds_changed_samples = 0;
1051                 goto out;
1052         }
1053         if (slot->ds_changed_samples) {
1054                 slot->ds_changed_samples = 0;
1055                 slot->ds_equal_samples = 0;
1056         }
1057 out:
1058         spin_unlock(&o2hb_live_lock);
1059
1060         if (queued)
1061                 o2hb_run_event_list(&event);
1062
1063         if (node)
1064                 o2nm_node_put(node);
1065         return changed;
1066 }
1067
1068 static int o2hb_highest_node(unsigned long *nodes, int numbits)
1069 {
1070         return find_last_bit(nodes, numbits);
1071 }
1072
1073 static int o2hb_lowest_node(unsigned long *nodes, int numbits)
1074 {
1075         return find_first_bit(nodes, numbits);
1076 }
1077
1078 static int o2hb_do_disk_heartbeat(struct o2hb_region *reg)
1079 {
1080         int i, ret, highest_node, lowest_node;
1081         int membership_change = 0, own_slot_ok = 0;
1082         unsigned long configured_nodes[BITS_TO_LONGS(O2NM_MAX_NODES)];
1083         unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
1084         struct o2hb_bio_wait_ctxt write_wc;
1085
1086         ret = o2nm_configured_node_map(configured_nodes,
1087                                        sizeof(configured_nodes));
1088         if (ret) {
1089                 mlog_errno(ret);
1090                 goto bail;
1091         }
1092
1093         /*
1094          * If a node is not configured but is in the livemap, we still need
1095          * to read the slot so as to be able to remove it from the livemap.
1096          */
1097         o2hb_fill_node_map(live_node_bitmap, O2NM_MAX_NODES);
1098         i = -1;
1099         while ((i = find_next_bit(live_node_bitmap,
1100                                   O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
1101                 set_bit(i, configured_nodes);
1102         }
1103
1104         highest_node = o2hb_highest_node(configured_nodes, O2NM_MAX_NODES);
1105         lowest_node = o2hb_lowest_node(configured_nodes, O2NM_MAX_NODES);
1106         if (highest_node >= O2NM_MAX_NODES || lowest_node >= O2NM_MAX_NODES) {
1107                 mlog(ML_NOTICE, "o2hb: No configured nodes found!\n");
1108                 ret = -EINVAL;
1109                 goto bail;
1110         }
1111
1112         /* No sense in reading the slots of nodes that don't exist
1113          * yet. Of course, if the node definitions have holes in them
1114          * then we're reading an empty slot anyway... Consider this
1115          * best-effort. */
1116         ret = o2hb_read_slots(reg, lowest_node, highest_node + 1);
1117         if (ret < 0) {
1118                 mlog_errno(ret);
1119                 goto bail;
1120         }
1121
1122         /* With an up to date view of the slots, we can check that no
1123          * other node has been improperly configured to heartbeat in
1124          * our slot. */
1125         own_slot_ok = o2hb_check_own_slot(reg);
1126
1127         /* fill in the proper info for our next heartbeat */
1128         o2hb_prepare_block(reg, reg->hr_generation);
1129
1130         ret = o2hb_issue_node_write(reg, &write_wc);
1131         if (ret < 0) {
1132                 mlog_errno(ret);
1133                 goto bail;
1134         }
1135
1136         i = -1;
1137         while((i = find_next_bit(configured_nodes,
1138                                  O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
1139                 membership_change |= o2hb_check_slot(reg, &reg->hr_slots[i]);
1140         }
1141
1142         /*
1143          * We have to be sure we've advertised ourselves on disk
1144          * before we can go to steady state.  This ensures that
1145          * people we find in our steady state have seen us.
1146          */
1147         o2hb_wait_on_io(&write_wc);
1148         if (write_wc.wc_error) {
1149                 /* Do not re-arm the write timeout on I/O error - we
1150                  * can't be sure that the new block ever made it to
1151                  * disk */
1152                 mlog(ML_ERROR, "Write error %d on device \"%pg\"\n",
1153                      write_wc.wc_error, reg_bdev(reg));
1154                 ret = write_wc.wc_error;
1155                 goto bail;
1156         }
1157
1158         /* Skip disarming the timeout if own slot has stale/bad data */
1159         if (own_slot_ok) {
1160                 o2hb_set_quorum_device(reg);
1161                 o2hb_arm_timeout(reg);
1162                 reg->hr_last_timeout_start = jiffies;
1163         }
1164
1165 bail:
1166         /* let the person who launched us know when things are steady */
1167         if (atomic_read(&reg->hr_steady_iterations) != 0) {
1168                 if (!ret && own_slot_ok && !membership_change) {
1169                         if (atomic_dec_and_test(&reg->hr_steady_iterations))
1170                                 wake_up(&o2hb_steady_queue);
1171                 }
1172         }
1173
1174         if (atomic_read(&reg->hr_steady_iterations) != 0) {
1175                 if (atomic_dec_and_test(&reg->hr_unsteady_iterations)) {
1176                         printk(KERN_NOTICE "o2hb: Unable to stabilize "
1177                                "heartbeat on region %s (%pg)\n",
1178                                config_item_name(&reg->hr_item),
1179                                reg_bdev(reg));
1180                         atomic_set(&reg->hr_steady_iterations, 0);
1181                         reg->hr_aborted_start = 1;
1182                         wake_up(&o2hb_steady_queue);
1183                         ret = -EIO;
1184                 }
1185         }
1186
1187         return ret;
1188 }
1189
1190 /*
1191  * we ride the region ref that the region dir holds.  before the region
1192  * dir is removed and drops it ref it will wait to tear down this
1193  * thread.
1194  */
1195 static int o2hb_thread(void *data)
1196 {
1197         int i, ret;
1198         struct o2hb_region *reg = data;
1199         struct o2hb_bio_wait_ctxt write_wc;
1200         ktime_t before_hb, after_hb;
1201         unsigned int elapsed_msec;
1202
1203         mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n");
1204
1205         set_user_nice(current, MIN_NICE);
1206
1207         /* Pin node */
1208         ret = o2nm_depend_this_node();
1209         if (ret) {
1210                 mlog(ML_ERROR, "Node has been deleted, ret = %d\n", ret);
1211                 reg->hr_node_deleted = 1;
1212                 wake_up(&o2hb_steady_queue);
1213                 return 0;
1214         }
1215
1216         while (!kthread_should_stop() &&
1217                !reg->hr_unclean_stop && !reg->hr_aborted_start) {
1218                 /* We track the time spent inside
1219                  * o2hb_do_disk_heartbeat so that we avoid more than
1220                  * hr_timeout_ms between disk writes. On busy systems
1221                  * this should result in a heartbeat which is less
1222                  * likely to time itself out. */
1223                 before_hb = ktime_get_real();
1224
1225                 ret = o2hb_do_disk_heartbeat(reg);
1226                 reg->hr_last_hb_status = ret;
1227
1228                 after_hb = ktime_get_real();
1229
1230                 elapsed_msec = (unsigned int)
1231                                 ktime_ms_delta(after_hb, before_hb);
1232
1233                 mlog(ML_HEARTBEAT,
1234                      "start = %lld, end = %lld, msec = %u, ret = %d\n",
1235                      before_hb, after_hb, elapsed_msec, ret);
1236
1237                 if (!kthread_should_stop() &&
1238                     elapsed_msec < reg->hr_timeout_ms) {
1239                         /* the kthread api has blocked signals for us so no
1240                          * need to record the return value. */
1241                         msleep_interruptible(reg->hr_timeout_ms - elapsed_msec);
1242                 }
1243         }
1244
1245         o2hb_disarm_timeout(reg);
1246
1247         /* unclean stop is only used in very bad situation */
1248         for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
1249                 o2hb_shutdown_slot(&reg->hr_slots[i]);
1250
1251         /* Explicit down notification - avoid forcing the other nodes
1252          * to timeout on this region when we could just as easily
1253          * write a clear generation - thus indicating to them that
1254          * this node has left this region.
1255          */
1256         if (!reg->hr_unclean_stop && !reg->hr_aborted_start) {
1257                 o2hb_prepare_block(reg, 0);
1258                 ret = o2hb_issue_node_write(reg, &write_wc);
1259                 if (ret == 0)
1260                         o2hb_wait_on_io(&write_wc);
1261                 else
1262                         mlog_errno(ret);
1263         }
1264
1265         /* Unpin node */
1266         o2nm_undepend_this_node();
1267
1268         mlog(ML_HEARTBEAT|ML_KTHREAD, "o2hb thread exiting\n");
1269
1270         return 0;
1271 }
1272
1273 #ifdef CONFIG_DEBUG_FS
1274 static int o2hb_debug_open(struct inode *inode, struct file *file)
1275 {
1276         struct o2hb_debug_buf *db = inode->i_private;
1277         struct o2hb_region *reg;
1278         unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1279         unsigned long lts;
1280         char *buf = NULL;
1281         int i = -1;
1282         int out = 0;
1283
1284         /* max_nodes should be the largest bitmap we pass here */
1285         BUG_ON(sizeof(map) < db->db_size);
1286
1287         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1288         if (!buf)
1289                 goto bail;
1290
1291         switch (db->db_type) {
1292         case O2HB_DB_TYPE_LIVENODES:
1293         case O2HB_DB_TYPE_LIVEREGIONS:
1294         case O2HB_DB_TYPE_QUORUMREGIONS:
1295         case O2HB_DB_TYPE_FAILEDREGIONS:
1296                 spin_lock(&o2hb_live_lock);
1297                 memcpy(map, db->db_data, db->db_size);
1298                 spin_unlock(&o2hb_live_lock);
1299                 break;
1300
1301         case O2HB_DB_TYPE_REGION_LIVENODES:
1302                 spin_lock(&o2hb_live_lock);
1303                 reg = (struct o2hb_region *)db->db_data;
1304                 memcpy(map, reg->hr_live_node_bitmap, db->db_size);
1305                 spin_unlock(&o2hb_live_lock);
1306                 break;
1307
1308         case O2HB_DB_TYPE_REGION_NUMBER:
1309                 reg = (struct o2hb_region *)db->db_data;
1310                 out += scnprintf(buf + out, PAGE_SIZE - out, "%d\n",
1311                                 reg->hr_region_num);
1312                 goto done;
1313
1314         case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
1315                 reg = (struct o2hb_region *)db->db_data;
1316                 lts = reg->hr_last_timeout_start;
1317                 /* If 0, it has never been set before */
1318                 if (lts)
1319                         lts = jiffies_to_msecs(jiffies - lts);
1320                 out += scnprintf(buf + out, PAGE_SIZE - out, "%lu\n", lts);
1321                 goto done;
1322
1323         case O2HB_DB_TYPE_REGION_PINNED:
1324                 reg = (struct o2hb_region *)db->db_data;
1325                 out += scnprintf(buf + out, PAGE_SIZE - out, "%u\n",
1326                                 !!reg->hr_item_pinned);
1327                 goto done;
1328
1329         default:
1330                 goto done;
1331         }
1332
1333         while ((i = find_next_bit(map, db->db_len, i + 1)) < db->db_len)
1334                 out += scnprintf(buf + out, PAGE_SIZE - out, "%d ", i);
1335         out += scnprintf(buf + out, PAGE_SIZE - out, "\n");
1336
1337 done:
1338         i_size_write(inode, out);
1339
1340         file->private_data = buf;
1341
1342         return 0;
1343 bail:
1344         return -ENOMEM;
1345 }
1346
1347 static int o2hb_debug_release(struct inode *inode, struct file *file)
1348 {
1349         kfree(file->private_data);
1350         return 0;
1351 }
1352
1353 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1354                                  size_t nbytes, loff_t *ppos)
1355 {
1356         return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
1357                                        i_size_read(file->f_mapping->host));
1358 }
1359 #else
1360 static int o2hb_debug_open(struct inode *inode, struct file *file)
1361 {
1362         return 0;
1363 }
1364 static int o2hb_debug_release(struct inode *inode, struct file *file)
1365 {
1366         return 0;
1367 }
1368 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1369                                size_t nbytes, loff_t *ppos)
1370 {
1371         return 0;
1372 }
1373 #endif  /* CONFIG_DEBUG_FS */
1374
1375 static const struct file_operations o2hb_debug_fops = {
1376         .open =         o2hb_debug_open,
1377         .release =      o2hb_debug_release,
1378         .read =         o2hb_debug_read,
1379         .llseek =       generic_file_llseek,
1380 };
1381
1382 void o2hb_exit(void)
1383 {
1384         debugfs_remove_recursive(o2hb_debug_dir);
1385         kfree(o2hb_db_livenodes);
1386         kfree(o2hb_db_liveregions);
1387         kfree(o2hb_db_quorumregions);
1388         kfree(o2hb_db_failedregions);
1389 }
1390
1391 static void o2hb_debug_create(const char *name, struct dentry *dir,
1392                               struct o2hb_debug_buf **db, int db_len, int type,
1393                               int size, int len, void *data)
1394 {
1395         *db = kmalloc(db_len, GFP_KERNEL);
1396         if (!*db)
1397                 return;
1398
1399         (*db)->db_type = type;
1400         (*db)->db_size = size;
1401         (*db)->db_len = len;
1402         (*db)->db_data = data;
1403
1404         debugfs_create_file(name, S_IFREG|S_IRUSR, dir, *db, &o2hb_debug_fops);
1405 }
1406
1407 static void o2hb_debug_init(void)
1408 {
1409         o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
1410
1411         o2hb_debug_create(O2HB_DEBUG_LIVENODES, o2hb_debug_dir,
1412                           &o2hb_db_livenodes, sizeof(*o2hb_db_livenodes),
1413                           O2HB_DB_TYPE_LIVENODES, sizeof(o2hb_live_node_bitmap),
1414                           O2NM_MAX_NODES, o2hb_live_node_bitmap);
1415
1416         o2hb_debug_create(O2HB_DEBUG_LIVEREGIONS, o2hb_debug_dir,
1417                           &o2hb_db_liveregions, sizeof(*o2hb_db_liveregions),
1418                           O2HB_DB_TYPE_LIVEREGIONS,
1419                           sizeof(o2hb_live_region_bitmap), O2NM_MAX_REGIONS,
1420                           o2hb_live_region_bitmap);
1421
1422         o2hb_debug_create(O2HB_DEBUG_QUORUMREGIONS, o2hb_debug_dir,
1423                           &o2hb_db_quorumregions,
1424                           sizeof(*o2hb_db_quorumregions),
1425                           O2HB_DB_TYPE_QUORUMREGIONS,
1426                           sizeof(o2hb_quorum_region_bitmap), O2NM_MAX_REGIONS,
1427                           o2hb_quorum_region_bitmap);
1428
1429         o2hb_debug_create(O2HB_DEBUG_FAILEDREGIONS, o2hb_debug_dir,
1430                           &o2hb_db_failedregions,
1431                           sizeof(*o2hb_db_failedregions),
1432                           O2HB_DB_TYPE_FAILEDREGIONS,
1433                           sizeof(o2hb_failed_region_bitmap), O2NM_MAX_REGIONS,
1434                           o2hb_failed_region_bitmap);
1435 }
1436
1437 void o2hb_init(void)
1438 {
1439         int i;
1440
1441         for (i = 0; i < ARRAY_SIZE(o2hb_callbacks); i++)
1442                 INIT_LIST_HEAD(&o2hb_callbacks[i].list);
1443
1444         for (i = 0; i < ARRAY_SIZE(o2hb_live_slots); i++)
1445                 INIT_LIST_HEAD(&o2hb_live_slots[i]);
1446
1447         bitmap_zero(o2hb_live_node_bitmap, O2NM_MAX_NODES);
1448         bitmap_zero(o2hb_region_bitmap, O2NM_MAX_REGIONS);
1449         bitmap_zero(o2hb_live_region_bitmap, O2NM_MAX_REGIONS);
1450         bitmap_zero(o2hb_quorum_region_bitmap, O2NM_MAX_REGIONS);
1451         bitmap_zero(o2hb_failed_region_bitmap, O2NM_MAX_REGIONS);
1452
1453         o2hb_dependent_users = 0;
1454
1455         o2hb_debug_init();
1456 }
1457
1458 /* if we're already in a callback then we're already serialized by the sem */
1459 static void o2hb_fill_node_map_from_callback(unsigned long *map,
1460                                              unsigned int bits)
1461 {
1462         bitmap_copy(map, o2hb_live_node_bitmap, bits);
1463 }
1464
1465 /*
1466  * get a map of all nodes that are heartbeating in any regions
1467  */
1468 void o2hb_fill_node_map(unsigned long *map, unsigned int bits)
1469 {
1470         /* callers want to serialize this map and callbacks so that they
1471          * can trust that they don't miss nodes coming to the party */
1472         down_read(&o2hb_callback_sem);
1473         spin_lock(&o2hb_live_lock);
1474         o2hb_fill_node_map_from_callback(map, bits);
1475         spin_unlock(&o2hb_live_lock);
1476         up_read(&o2hb_callback_sem);
1477 }
1478 EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
1479
1480 /*
1481  * heartbeat configfs bits.  The heartbeat set is a default set under
1482  * the cluster set in nodemanager.c.
1483  */
1484
1485 static struct o2hb_region *to_o2hb_region(struct config_item *item)
1486 {
1487         return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
1488 }
1489
1490 /* drop_item only drops its ref after killing the thread, nothing should
1491  * be using the region anymore.  this has to clean up any state that
1492  * attributes might have built up. */
1493 static void o2hb_region_release(struct config_item *item)
1494 {
1495         int i;
1496         struct page *page;
1497         struct o2hb_region *reg = to_o2hb_region(item);
1498
1499         mlog(ML_HEARTBEAT, "hb region release (%pg)\n", reg_bdev(reg));
1500
1501         kfree(reg->hr_tmp_block);
1502
1503         if (reg->hr_slot_data) {
1504                 for (i = 0; i < reg->hr_num_pages; i++) {
1505                         page = reg->hr_slot_data[i];
1506                         if (page)
1507                                 __free_page(page);
1508                 }
1509                 kfree(reg->hr_slot_data);
1510         }
1511
1512         if (reg->hr_bdev_file)
1513                 fput(reg->hr_bdev_file);
1514
1515         kfree(reg->hr_slots);
1516
1517         debugfs_remove_recursive(reg->hr_debug_dir);
1518         kfree(reg->hr_db_livenodes);
1519         kfree(reg->hr_db_regnum);
1520         kfree(reg->hr_db_elapsed_time);
1521         kfree(reg->hr_db_pinned);
1522
1523         spin_lock(&o2hb_live_lock);
1524         list_del(&reg->hr_all_item);
1525         spin_unlock(&o2hb_live_lock);
1526
1527         o2net_unregister_handler_list(&reg->hr_handler_list);
1528         kfree(reg);
1529 }
1530
1531 static int o2hb_read_block_input(struct o2hb_region *reg,
1532                                  const char *page,
1533                                  unsigned long *ret_bytes,
1534                                  unsigned int *ret_bits)
1535 {
1536         unsigned long bytes;
1537         char *p = (char *)page;
1538
1539         bytes = simple_strtoul(p, &p, 0);
1540         if (!p || (*p && (*p != '\n')))
1541                 return -EINVAL;
1542
1543         /* Heartbeat and fs min / max block sizes are the same. */
1544         if (bytes > 4096 || bytes < 512)
1545                 return -ERANGE;
1546         if (hweight16(bytes) != 1)
1547                 return -EINVAL;
1548
1549         if (ret_bytes)
1550                 *ret_bytes = bytes;
1551         if (ret_bits)
1552                 *ret_bits = ffs(bytes) - 1;
1553
1554         return 0;
1555 }
1556
1557 static ssize_t o2hb_region_block_bytes_show(struct config_item *item,
1558                                             char *page)
1559 {
1560         return sprintf(page, "%u\n", to_o2hb_region(item)->hr_block_bytes);
1561 }
1562
1563 static ssize_t o2hb_region_block_bytes_store(struct config_item *item,
1564                                              const char *page,
1565                                              size_t count)
1566 {
1567         struct o2hb_region *reg = to_o2hb_region(item);
1568         int status;
1569         unsigned long block_bytes;
1570         unsigned int block_bits;
1571
1572         if (reg->hr_bdev_file)
1573                 return -EINVAL;
1574
1575         status = o2hb_read_block_input(reg, page, &block_bytes,
1576                                        &block_bits);
1577         if (status)
1578                 return status;
1579
1580         reg->hr_block_bytes = (unsigned int)block_bytes;
1581         reg->hr_block_bits = block_bits;
1582
1583         return count;
1584 }
1585
1586 static ssize_t o2hb_region_start_block_show(struct config_item *item,
1587                                             char *page)
1588 {
1589         return sprintf(page, "%llu\n", to_o2hb_region(item)->hr_start_block);
1590 }
1591
1592 static ssize_t o2hb_region_start_block_store(struct config_item *item,
1593                                              const char *page,
1594                                              size_t count)
1595 {
1596         struct o2hb_region *reg = to_o2hb_region(item);
1597         unsigned long long tmp;
1598         char *p = (char *)page;
1599         ssize_t ret;
1600
1601         if (reg->hr_bdev_file)
1602                 return -EINVAL;
1603
1604         ret = kstrtoull(p, 0, &tmp);
1605         if (ret)
1606                 return -EINVAL;
1607
1608         reg->hr_start_block = tmp;
1609
1610         return count;
1611 }
1612
1613 static ssize_t o2hb_region_blocks_show(struct config_item *item, char *page)
1614 {
1615         return sprintf(page, "%d\n", to_o2hb_region(item)->hr_blocks);
1616 }
1617
1618 static ssize_t o2hb_region_blocks_store(struct config_item *item,
1619                                         const char *page,
1620                                         size_t count)
1621 {
1622         struct o2hb_region *reg = to_o2hb_region(item);
1623         unsigned long tmp;
1624         char *p = (char *)page;
1625
1626         if (reg->hr_bdev_file)
1627                 return -EINVAL;
1628
1629         tmp = simple_strtoul(p, &p, 0);
1630         if (!p || (*p && (*p != '\n')))
1631                 return -EINVAL;
1632
1633         if (tmp > O2NM_MAX_NODES || tmp == 0)
1634                 return -ERANGE;
1635
1636         reg->hr_blocks = (unsigned int)tmp;
1637
1638         return count;
1639 }
1640
1641 static ssize_t o2hb_region_dev_show(struct config_item *item, char *page)
1642 {
1643         unsigned int ret = 0;
1644
1645         if (to_o2hb_region(item)->hr_bdev_file)
1646                 ret = sprintf(page, "%pg\n", reg_bdev(to_o2hb_region(item)));
1647
1648         return ret;
1649 }
1650
1651 static void o2hb_init_region_params(struct o2hb_region *reg)
1652 {
1653         reg->hr_slots_per_page = PAGE_SIZE >> reg->hr_block_bits;
1654         reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
1655
1656         mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
1657              reg->hr_start_block, reg->hr_blocks);
1658         mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
1659              reg->hr_block_bytes, reg->hr_block_bits);
1660         mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
1661         mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
1662 }
1663
1664 static int o2hb_map_slot_data(struct o2hb_region *reg)
1665 {
1666         int i, j;
1667         unsigned int last_slot;
1668         unsigned int spp = reg->hr_slots_per_page;
1669         struct page *page;
1670         char *raw;
1671         struct o2hb_disk_slot *slot;
1672
1673         reg->hr_tmp_block = kmalloc(reg->hr_block_bytes, GFP_KERNEL);
1674         if (reg->hr_tmp_block == NULL)
1675                 return -ENOMEM;
1676
1677         reg->hr_slots = kcalloc(reg->hr_blocks,
1678                                 sizeof(struct o2hb_disk_slot), GFP_KERNEL);
1679         if (reg->hr_slots == NULL)
1680                 return -ENOMEM;
1681
1682         for(i = 0; i < reg->hr_blocks; i++) {
1683                 slot = &reg->hr_slots[i];
1684                 slot->ds_node_num = i;
1685                 INIT_LIST_HEAD(&slot->ds_live_item);
1686                 slot->ds_raw_block = NULL;
1687         }
1688
1689         reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
1690         mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
1691                            "at %u blocks per page\n",
1692              reg->hr_num_pages, reg->hr_blocks, spp);
1693
1694         reg->hr_slot_data = kcalloc(reg->hr_num_pages, sizeof(struct page *),
1695                                     GFP_KERNEL);
1696         if (!reg->hr_slot_data)
1697                 return -ENOMEM;
1698
1699         for(i = 0; i < reg->hr_num_pages; i++) {
1700                 page = alloc_page(GFP_KERNEL);
1701                 if (!page)
1702                         return -ENOMEM;
1703
1704                 reg->hr_slot_data[i] = page;
1705
1706                 last_slot = i * spp;
1707                 raw = page_address(page);
1708                 for (j = 0;
1709                      (j < spp) && ((j + last_slot) < reg->hr_blocks);
1710                      j++) {
1711                         BUG_ON((j + last_slot) >= reg->hr_blocks);
1712
1713                         slot = &reg->hr_slots[j + last_slot];
1714                         slot->ds_raw_block =
1715                                 (struct o2hb_disk_heartbeat_block *) raw;
1716
1717                         raw += reg->hr_block_bytes;
1718                 }
1719         }
1720
1721         return 0;
1722 }
1723
1724 /* Read in all the slots available and populate the tracking
1725  * structures so that we can start with a baseline idea of what's
1726  * there. */
1727 static int o2hb_populate_slot_data(struct o2hb_region *reg)
1728 {
1729         int ret, i;
1730         struct o2hb_disk_slot *slot;
1731         struct o2hb_disk_heartbeat_block *hb_block;
1732
1733         ret = o2hb_read_slots(reg, 0, reg->hr_blocks);
1734         if (ret)
1735                 goto out;
1736
1737         /* We only want to get an idea of the values initially in each
1738          * slot, so we do no verification - o2hb_check_slot will
1739          * actually determine if each configured slot is valid and
1740          * whether any values have changed. */
1741         for(i = 0; i < reg->hr_blocks; i++) {
1742                 slot = &reg->hr_slots[i];
1743                 hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
1744
1745                 /* Only fill the values that o2hb_check_slot uses to
1746                  * determine changing slots */
1747                 slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
1748                 slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
1749         }
1750
1751 out:
1752         return ret;
1753 }
1754
1755 /*
1756  * this is acting as commit; we set up all of hr_bdev_file and hr_task or
1757  * nothing
1758  */
1759 static ssize_t o2hb_region_dev_store(struct config_item *item,
1760                                      const char *page,
1761                                      size_t count)
1762 {
1763         struct o2hb_region *reg = to_o2hb_region(item);
1764         struct task_struct *hb_task;
1765         long fd;
1766         int sectsize;
1767         char *p = (char *)page;
1768         struct fd f;
1769         ssize_t ret = -EINVAL;
1770         int live_threshold;
1771
1772         if (reg->hr_bdev_file)
1773                 goto out;
1774
1775         /* We can't heartbeat without having had our node number
1776          * configured yet. */
1777         if (o2nm_this_node() == O2NM_MAX_NODES)
1778                 goto out;
1779
1780         fd = simple_strtol(p, &p, 0);
1781         if (!p || (*p && (*p != '\n')))
1782                 goto out;
1783
1784         if (fd < 0 || fd >= INT_MAX)
1785                 goto out;
1786
1787         f = fdget(fd);
1788         if (f.file == NULL)
1789                 goto out;
1790
1791         if (reg->hr_blocks == 0 || reg->hr_start_block == 0 ||
1792             reg->hr_block_bytes == 0)
1793                 goto out2;
1794
1795         if (!S_ISBLK(f.file->f_mapping->host->i_mode))
1796                 goto out2;
1797
1798         reg->hr_bdev_file = bdev_file_open_by_dev(f.file->f_mapping->host->i_rdev,
1799                         BLK_OPEN_WRITE | BLK_OPEN_READ, NULL, NULL);
1800         if (IS_ERR(reg->hr_bdev_file)) {
1801                 ret = PTR_ERR(reg->hr_bdev_file);
1802                 reg->hr_bdev_file = NULL;
1803                 goto out2;
1804         }
1805
1806         sectsize = bdev_logical_block_size(reg_bdev(reg));
1807         if (sectsize != reg->hr_block_bytes) {
1808                 mlog(ML_ERROR,
1809                      "blocksize %u incorrect for device, expected %d",
1810                      reg->hr_block_bytes, sectsize);
1811                 ret = -EINVAL;
1812                 goto out3;
1813         }
1814
1815         o2hb_init_region_params(reg);
1816
1817         /* Generation of zero is invalid */
1818         do {
1819                 get_random_bytes(&reg->hr_generation,
1820                                  sizeof(reg->hr_generation));
1821         } while (reg->hr_generation == 0);
1822
1823         ret = o2hb_map_slot_data(reg);
1824         if (ret) {
1825                 mlog_errno(ret);
1826                 goto out3;
1827         }
1828
1829         ret = o2hb_populate_slot_data(reg);
1830         if (ret) {
1831                 mlog_errno(ret);
1832                 goto out3;
1833         }
1834
1835         INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
1836         INIT_DELAYED_WORK(&reg->hr_nego_timeout_work, o2hb_nego_timeout);
1837
1838         /*
1839          * A node is considered live after it has beat LIVE_THRESHOLD
1840          * times.  We're not steady until we've given them a chance
1841          * _after_ our first read.
1842          * The default threshold is bare minimum so as to limit the delay
1843          * during mounts. For global heartbeat, the threshold doubled for the
1844          * first region.
1845          */
1846         live_threshold = O2HB_LIVE_THRESHOLD;
1847         if (o2hb_global_heartbeat_active()) {
1848                 spin_lock(&o2hb_live_lock);
1849                 if (bitmap_weight(o2hb_region_bitmap, O2NM_MAX_REGIONS) == 1)
1850                         live_threshold <<= 1;
1851                 spin_unlock(&o2hb_live_lock);
1852         }
1853         ++live_threshold;
1854         atomic_set(&reg->hr_steady_iterations, live_threshold);
1855         /* unsteady_iterations is triple the steady_iterations */
1856         atomic_set(&reg->hr_unsteady_iterations, (live_threshold * 3));
1857
1858         hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
1859                               reg->hr_item.ci_name);
1860         if (IS_ERR(hb_task)) {
1861                 ret = PTR_ERR(hb_task);
1862                 mlog_errno(ret);
1863                 goto out3;
1864         }
1865
1866         spin_lock(&o2hb_live_lock);
1867         reg->hr_task = hb_task;
1868         spin_unlock(&o2hb_live_lock);
1869
1870         ret = wait_event_interruptible(o2hb_steady_queue,
1871                                 atomic_read(&reg->hr_steady_iterations) == 0 ||
1872                                 reg->hr_node_deleted);
1873         if (ret) {
1874                 atomic_set(&reg->hr_steady_iterations, 0);
1875                 reg->hr_aborted_start = 1;
1876         }
1877
1878         if (reg->hr_aborted_start) {
1879                 ret = -EIO;
1880                 goto out3;
1881         }
1882
1883         if (reg->hr_node_deleted) {
1884                 ret = -EINVAL;
1885                 goto out3;
1886         }
1887
1888         /* Ok, we were woken.  Make sure it wasn't by drop_item() */
1889         spin_lock(&o2hb_live_lock);
1890         hb_task = reg->hr_task;
1891         if (o2hb_global_heartbeat_active())
1892                 set_bit(reg->hr_region_num, o2hb_live_region_bitmap);
1893         spin_unlock(&o2hb_live_lock);
1894
1895         if (hb_task)
1896                 ret = count;
1897         else
1898                 ret = -EIO;
1899
1900         if (hb_task && o2hb_global_heartbeat_active())
1901                 printk(KERN_NOTICE "o2hb: Heartbeat started on region %s (%pg)\n",
1902                        config_item_name(&reg->hr_item), reg_bdev(reg));
1903
1904 out3:
1905         if (ret < 0) {
1906                 fput(reg->hr_bdev_file);
1907                 reg->hr_bdev_file = NULL;
1908         }
1909 out2:
1910         fdput(f);
1911 out:
1912         return ret;
1913 }
1914
1915 static ssize_t o2hb_region_pid_show(struct config_item *item, char *page)
1916 {
1917         struct o2hb_region *reg = to_o2hb_region(item);
1918         pid_t pid = 0;
1919
1920         spin_lock(&o2hb_live_lock);
1921         if (reg->hr_task)
1922                 pid = task_pid_nr(reg->hr_task);
1923         spin_unlock(&o2hb_live_lock);
1924
1925         if (!pid)
1926                 return 0;
1927
1928         return sprintf(page, "%u\n", pid);
1929 }
1930
1931 CONFIGFS_ATTR(o2hb_region_, block_bytes);
1932 CONFIGFS_ATTR(o2hb_region_, start_block);
1933 CONFIGFS_ATTR(o2hb_region_, blocks);
1934 CONFIGFS_ATTR(o2hb_region_, dev);
1935 CONFIGFS_ATTR_RO(o2hb_region_, pid);
1936
1937 static struct configfs_attribute *o2hb_region_attrs[] = {
1938         &o2hb_region_attr_block_bytes,
1939         &o2hb_region_attr_start_block,
1940         &o2hb_region_attr_blocks,
1941         &o2hb_region_attr_dev,
1942         &o2hb_region_attr_pid,
1943         NULL,
1944 };
1945
1946 static struct configfs_item_operations o2hb_region_item_ops = {
1947         .release                = o2hb_region_release,
1948 };
1949
1950 static const struct config_item_type o2hb_region_type = {
1951         .ct_item_ops    = &o2hb_region_item_ops,
1952         .ct_attrs       = o2hb_region_attrs,
1953         .ct_owner       = THIS_MODULE,
1954 };
1955
1956 /* heartbeat set */
1957
1958 struct o2hb_heartbeat_group {
1959         struct config_group hs_group;
1960         /* some stuff? */
1961 };
1962
1963 static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
1964 {
1965         return group ?
1966                 container_of(group, struct o2hb_heartbeat_group, hs_group)
1967                 : NULL;
1968 }
1969
1970 static void o2hb_debug_region_init(struct o2hb_region *reg,
1971                                    struct dentry *parent)
1972 {
1973         struct dentry *dir;
1974
1975         dir = debugfs_create_dir(config_item_name(&reg->hr_item), parent);
1976         reg->hr_debug_dir = dir;
1977
1978         o2hb_debug_create(O2HB_DEBUG_LIVENODES, dir, &(reg->hr_db_livenodes),
1979                           sizeof(*(reg->hr_db_livenodes)),
1980                           O2HB_DB_TYPE_REGION_LIVENODES,
1981                           sizeof(reg->hr_live_node_bitmap), O2NM_MAX_NODES,
1982                           reg);
1983
1984         o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER, dir, &(reg->hr_db_regnum),
1985                           sizeof(*(reg->hr_db_regnum)),
1986                           O2HB_DB_TYPE_REGION_NUMBER, 0, O2NM_MAX_NODES, reg);
1987
1988         o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME, dir,
1989                           &(reg->hr_db_elapsed_time),
1990                           sizeof(*(reg->hr_db_elapsed_time)),
1991                           O2HB_DB_TYPE_REGION_ELAPSED_TIME, 0, 0, reg);
1992
1993         o2hb_debug_create(O2HB_DEBUG_REGION_PINNED, dir, &(reg->hr_db_pinned),
1994                           sizeof(*(reg->hr_db_pinned)),
1995                           O2HB_DB_TYPE_REGION_PINNED, 0, 0, reg);
1996
1997 }
1998
1999 static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
2000                                                           const char *name)
2001 {
2002         struct o2hb_region *reg = NULL;
2003         int ret;
2004
2005         reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
2006         if (reg == NULL)
2007                 return ERR_PTR(-ENOMEM);
2008
2009         if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
2010                 ret = -ENAMETOOLONG;
2011                 goto free;
2012         }
2013
2014         spin_lock(&o2hb_live_lock);
2015         reg->hr_region_num = 0;
2016         if (o2hb_global_heartbeat_active()) {
2017                 reg->hr_region_num = find_first_zero_bit(o2hb_region_bitmap,
2018                                                          O2NM_MAX_REGIONS);
2019                 if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
2020                         spin_unlock(&o2hb_live_lock);
2021                         ret = -EFBIG;
2022                         goto free;
2023                 }
2024                 set_bit(reg->hr_region_num, o2hb_region_bitmap);
2025         }
2026         list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
2027         spin_unlock(&o2hb_live_lock);
2028
2029         config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
2030
2031         /* this is the same way to generate msg key as dlm, for local heartbeat,
2032          * name is also the same, so make initial crc value different to avoid
2033          * message key conflict.
2034          */
2035         reg->hr_key = crc32_le(reg->hr_region_num + O2NM_MAX_REGIONS,
2036                 name, strlen(name));
2037         INIT_LIST_HEAD(&reg->hr_handler_list);
2038         ret = o2net_register_handler(O2HB_NEGO_TIMEOUT_MSG, reg->hr_key,
2039                         sizeof(struct o2hb_nego_msg),
2040                         o2hb_nego_timeout_handler,
2041                         reg, NULL, &reg->hr_handler_list);
2042         if (ret)
2043                 goto remove_item;
2044
2045         ret = o2net_register_handler(O2HB_NEGO_APPROVE_MSG, reg->hr_key,
2046                         sizeof(struct o2hb_nego_msg),
2047                         o2hb_nego_approve_handler,
2048                         reg, NULL, &reg->hr_handler_list);
2049         if (ret)
2050                 goto unregister_handler;
2051
2052         o2hb_debug_region_init(reg, o2hb_debug_dir);
2053
2054         return &reg->hr_item;
2055
2056 unregister_handler:
2057         o2net_unregister_handler_list(&reg->hr_handler_list);
2058 remove_item:
2059         spin_lock(&o2hb_live_lock);
2060         list_del(&reg->hr_all_item);
2061         if (o2hb_global_heartbeat_active())
2062                 clear_bit(reg->hr_region_num, o2hb_region_bitmap);
2063         spin_unlock(&o2hb_live_lock);
2064 free:
2065         kfree(reg);
2066         return ERR_PTR(ret);
2067 }
2068
2069 static void o2hb_heartbeat_group_drop_item(struct config_group *group,
2070                                            struct config_item *item)
2071 {
2072         struct task_struct *hb_task;
2073         struct o2hb_region *reg = to_o2hb_region(item);
2074         int quorum_region = 0;
2075
2076         /* stop the thread when the user removes the region dir */
2077         spin_lock(&o2hb_live_lock);
2078         hb_task = reg->hr_task;
2079         reg->hr_task = NULL;
2080         reg->hr_item_dropped = 1;
2081         spin_unlock(&o2hb_live_lock);
2082
2083         if (hb_task)
2084                 kthread_stop(hb_task);
2085
2086         if (o2hb_global_heartbeat_active()) {
2087                 spin_lock(&o2hb_live_lock);
2088                 clear_bit(reg->hr_region_num, o2hb_region_bitmap);
2089                 clear_bit(reg->hr_region_num, o2hb_live_region_bitmap);
2090                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
2091                         quorum_region = 1;
2092                 clear_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
2093                 spin_unlock(&o2hb_live_lock);
2094                 printk(KERN_NOTICE "o2hb: Heartbeat %s on region %s (%pg)\n",
2095                        ((atomic_read(&reg->hr_steady_iterations) == 0) ?
2096                         "stopped" : "start aborted"), config_item_name(item),
2097                        reg_bdev(reg));
2098         }
2099
2100         /*
2101          * If we're racing a dev_write(), we need to wake them.  They will
2102          * check reg->hr_task
2103          */
2104         if (atomic_read(&reg->hr_steady_iterations) != 0) {
2105                 reg->hr_aborted_start = 1;
2106                 atomic_set(&reg->hr_steady_iterations, 0);
2107                 wake_up(&o2hb_steady_queue);
2108         }
2109
2110         config_item_put(item);
2111
2112         if (!o2hb_global_heartbeat_active() || !quorum_region)
2113                 return;
2114
2115         /*
2116          * If global heartbeat active and there are dependent users,
2117          * pin all regions if quorum region count <= CUT_OFF
2118          */
2119         spin_lock(&o2hb_live_lock);
2120
2121         if (!o2hb_dependent_users)
2122                 goto unlock;
2123
2124         if (bitmap_weight(o2hb_quorum_region_bitmap,
2125                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2126                 o2hb_region_pin(NULL);
2127
2128 unlock:
2129         spin_unlock(&o2hb_live_lock);
2130 }
2131
2132 static ssize_t o2hb_heartbeat_group_dead_threshold_show(struct config_item *item,
2133                 char *page)
2134 {
2135         return sprintf(page, "%u\n", o2hb_dead_threshold);
2136 }
2137
2138 static ssize_t o2hb_heartbeat_group_dead_threshold_store(struct config_item *item,
2139                 const char *page, size_t count)
2140 {
2141         unsigned long tmp;
2142         char *p = (char *)page;
2143
2144         tmp = simple_strtoul(p, &p, 10);
2145         if (!p || (*p && (*p != '\n')))
2146                 return -EINVAL;
2147
2148         /* this will validate ranges for us. */
2149         o2hb_dead_threshold_set((unsigned int) tmp);
2150
2151         return count;
2152 }
2153
2154 static ssize_t o2hb_heartbeat_group_mode_show(struct config_item *item,
2155                 char *page)
2156 {
2157         return sprintf(page, "%s\n",
2158                        o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
2159 }
2160
2161 static ssize_t o2hb_heartbeat_group_mode_store(struct config_item *item,
2162                 const char *page, size_t count)
2163 {
2164         unsigned int i;
2165         int ret;
2166         size_t len;
2167
2168         len = (page[count - 1] == '\n') ? count - 1 : count;
2169         if (!len)
2170                 return -EINVAL;
2171
2172         for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
2173                 if (strncasecmp(page, o2hb_heartbeat_mode_desc[i], len))
2174                         continue;
2175
2176                 ret = o2hb_global_heartbeat_mode_set(i);
2177                 if (!ret)
2178                         printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
2179                                o2hb_heartbeat_mode_desc[i]);
2180                 return count;
2181         }
2182
2183         return -EINVAL;
2184
2185 }
2186
2187 CONFIGFS_ATTR(o2hb_heartbeat_group_, dead_threshold);
2188 CONFIGFS_ATTR(o2hb_heartbeat_group_, mode);
2189
2190 static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
2191         &o2hb_heartbeat_group_attr_dead_threshold,
2192         &o2hb_heartbeat_group_attr_mode,
2193         NULL,
2194 };
2195
2196 static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
2197         .make_item      = o2hb_heartbeat_group_make_item,
2198         .drop_item      = o2hb_heartbeat_group_drop_item,
2199 };
2200
2201 static const struct config_item_type o2hb_heartbeat_group_type = {
2202         .ct_group_ops   = &o2hb_heartbeat_group_group_ops,
2203         .ct_attrs       = o2hb_heartbeat_group_attrs,
2204         .ct_owner       = THIS_MODULE,
2205 };
2206
2207 /* this is just here to avoid touching group in heartbeat.h which the
2208  * entire damn world #includes */
2209 struct config_group *o2hb_alloc_hb_set(void)
2210 {
2211         struct o2hb_heartbeat_group *hs = NULL;
2212         struct config_group *ret = NULL;
2213
2214         hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
2215         if (hs == NULL)
2216                 goto out;
2217
2218         config_group_init_type_name(&hs->hs_group, "heartbeat",
2219                                     &o2hb_heartbeat_group_type);
2220
2221         ret = &hs->hs_group;
2222 out:
2223         if (ret == NULL)
2224                 kfree(hs);
2225         return ret;
2226 }
2227
2228 void o2hb_free_hb_set(struct config_group *group)
2229 {
2230         struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
2231         kfree(hs);
2232 }
2233
2234 /* hb callback registration and issuing */
2235
2236 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
2237 {
2238         if (type == O2HB_NUM_CB)
2239                 return ERR_PTR(-EINVAL);
2240
2241         return &o2hb_callbacks[type];
2242 }
2243
2244 void o2hb_setup_callback(struct o2hb_callback_func *hc,
2245                          enum o2hb_callback_type type,
2246                          o2hb_cb_func *func,
2247                          void *data,
2248                          int priority)
2249 {
2250         INIT_LIST_HEAD(&hc->hc_item);
2251         hc->hc_func = func;
2252         hc->hc_data = data;
2253         hc->hc_priority = priority;
2254         hc->hc_type = type;
2255         hc->hc_magic = O2HB_CB_MAGIC;
2256 }
2257 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
2258
2259 /*
2260  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2261  * In global heartbeat mode, region_uuid passed is NULL.
2262  *
2263  * In local, we only pin the matching region. In global we pin all the active
2264  * regions.
2265  */
2266 static int o2hb_region_pin(const char *region_uuid)
2267 {
2268         int ret = 0, found = 0;
2269         struct o2hb_region *reg;
2270         char *uuid;
2271
2272         assert_spin_locked(&o2hb_live_lock);
2273
2274         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2275                 if (reg->hr_item_dropped)
2276                         continue;
2277
2278                 uuid = config_item_name(&reg->hr_item);
2279
2280                 /* local heartbeat */
2281                 if (region_uuid) {
2282                         if (strcmp(region_uuid, uuid))
2283                                 continue;
2284                         found = 1;
2285                 }
2286
2287                 if (reg->hr_item_pinned || reg->hr_item_dropped)
2288                         goto skip_pin;
2289
2290                 /* Ignore ENOENT only for local hb (userdlm domain) */
2291                 ret = o2nm_depend_item(&reg->hr_item);
2292                 if (!ret) {
2293                         mlog(ML_CLUSTER, "Pin region %s\n", uuid);
2294                         reg->hr_item_pinned = 1;
2295                 } else {
2296                         if (ret == -ENOENT && found)
2297                                 ret = 0;
2298                         else {
2299                                 mlog(ML_ERROR, "Pin region %s fails with %d\n",
2300                                      uuid, ret);
2301                                 break;
2302                         }
2303                 }
2304 skip_pin:
2305                 if (found)
2306                         break;
2307         }
2308
2309         return ret;
2310 }
2311
2312 /*
2313  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2314  * In global heartbeat mode, region_uuid passed is NULL.
2315  *
2316  * In local, we only unpin the matching region. In global we unpin all the
2317  * active regions.
2318  */
2319 static void o2hb_region_unpin(const char *region_uuid)
2320 {
2321         struct o2hb_region *reg;
2322         char *uuid;
2323         int found = 0;
2324
2325         assert_spin_locked(&o2hb_live_lock);
2326
2327         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2328                 if (reg->hr_item_dropped)
2329                         continue;
2330
2331                 uuid = config_item_name(&reg->hr_item);
2332                 if (region_uuid) {
2333                         if (strcmp(region_uuid, uuid))
2334                                 continue;
2335                         found = 1;
2336                 }
2337
2338                 if (reg->hr_item_pinned) {
2339                         mlog(ML_CLUSTER, "Unpin region %s\n", uuid);
2340                         o2nm_undepend_item(&reg->hr_item);
2341                         reg->hr_item_pinned = 0;
2342                 }
2343                 if (found)
2344                         break;
2345         }
2346 }
2347
2348 static int o2hb_region_inc_user(const char *region_uuid)
2349 {
2350         int ret = 0;
2351
2352         spin_lock(&o2hb_live_lock);
2353
2354         /* local heartbeat */
2355         if (!o2hb_global_heartbeat_active()) {
2356             ret = o2hb_region_pin(region_uuid);
2357             goto unlock;
2358         }
2359
2360         /*
2361          * if global heartbeat active and this is the first dependent user,
2362          * pin all regions if quorum region count <= CUT_OFF
2363          */
2364         o2hb_dependent_users++;
2365         if (o2hb_dependent_users > 1)
2366                 goto unlock;
2367
2368         if (bitmap_weight(o2hb_quorum_region_bitmap,
2369                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2370                 ret = o2hb_region_pin(NULL);
2371
2372 unlock:
2373         spin_unlock(&o2hb_live_lock);
2374         return ret;
2375 }
2376
2377 static void o2hb_region_dec_user(const char *region_uuid)
2378 {
2379         spin_lock(&o2hb_live_lock);
2380
2381         /* local heartbeat */
2382         if (!o2hb_global_heartbeat_active()) {
2383             o2hb_region_unpin(region_uuid);
2384             goto unlock;
2385         }
2386
2387         /*
2388          * if global heartbeat active and there are no dependent users,
2389          * unpin all quorum regions
2390          */
2391         o2hb_dependent_users--;
2392         if (!o2hb_dependent_users)
2393                 o2hb_region_unpin(NULL);
2394
2395 unlock:
2396         spin_unlock(&o2hb_live_lock);
2397 }
2398
2399 int o2hb_register_callback(const char *region_uuid,
2400                            struct o2hb_callback_func *hc)
2401 {
2402         struct o2hb_callback_func *f;
2403         struct o2hb_callback *hbcall;
2404         int ret;
2405
2406         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2407         BUG_ON(!list_empty(&hc->hc_item));
2408
2409         hbcall = hbcall_from_type(hc->hc_type);
2410         if (IS_ERR(hbcall)) {
2411                 ret = PTR_ERR(hbcall);
2412                 goto out;
2413         }
2414
2415         if (region_uuid) {
2416                 ret = o2hb_region_inc_user(region_uuid);
2417                 if (ret) {
2418                         mlog_errno(ret);
2419                         goto out;
2420                 }
2421         }
2422
2423         down_write(&o2hb_callback_sem);
2424
2425         list_for_each_entry(f, &hbcall->list, hc_item) {
2426                 if (hc->hc_priority < f->hc_priority) {
2427                         list_add_tail(&hc->hc_item, &f->hc_item);
2428                         break;
2429                 }
2430         }
2431         if (list_empty(&hc->hc_item))
2432                 list_add_tail(&hc->hc_item, &hbcall->list);
2433
2434         up_write(&o2hb_callback_sem);
2435         ret = 0;
2436 out:
2437         mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
2438              ret, __builtin_return_address(0), hc);
2439         return ret;
2440 }
2441 EXPORT_SYMBOL_GPL(o2hb_register_callback);
2442
2443 void o2hb_unregister_callback(const char *region_uuid,
2444                               struct o2hb_callback_func *hc)
2445 {
2446         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2447
2448         mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
2449              __builtin_return_address(0), hc);
2450
2451         /* XXX Can this happen _with_ a region reference? */
2452         if (list_empty(&hc->hc_item))
2453                 return;
2454
2455         if (region_uuid)
2456                 o2hb_region_dec_user(region_uuid);
2457
2458         down_write(&o2hb_callback_sem);
2459
2460         list_del_init(&hc->hc_item);
2461
2462         up_write(&o2hb_callback_sem);
2463 }
2464 EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
2465
2466 int o2hb_check_node_heartbeating_no_sem(u8 node_num)
2467 {
2468         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2469
2470         spin_lock(&o2hb_live_lock);
2471         o2hb_fill_node_map_from_callback(testing_map, O2NM_MAX_NODES);
2472         spin_unlock(&o2hb_live_lock);
2473         if (!test_bit(node_num, testing_map)) {
2474                 mlog(ML_HEARTBEAT,
2475                      "node (%u) does not have heartbeating enabled.\n",
2476                      node_num);
2477                 return 0;
2478         }
2479
2480         return 1;
2481 }
2482 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_no_sem);
2483
2484 int o2hb_check_node_heartbeating_from_callback(u8 node_num)
2485 {
2486         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2487
2488         o2hb_fill_node_map_from_callback(testing_map, O2NM_MAX_NODES);
2489         if (!test_bit(node_num, testing_map)) {
2490                 mlog(ML_HEARTBEAT,
2491                      "node (%u) does not have heartbeating enabled.\n",
2492                      node_num);
2493                 return 0;
2494         }
2495
2496         return 1;
2497 }
2498 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_from_callback);
2499
2500 /*
2501  * this is just a hack until we get the plumbing which flips file systems
2502  * read only and drops the hb ref instead of killing the node dead.
2503  */
2504 void o2hb_stop_all_regions(void)
2505 {
2506         struct o2hb_region *reg;
2507
2508         mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");
2509
2510         spin_lock(&o2hb_live_lock);
2511
2512         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
2513                 reg->hr_unclean_stop = 1;
2514
2515         spin_unlock(&o2hb_live_lock);
2516 }
2517 EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
2518
2519 int o2hb_get_all_regions(char *region_uuids, u8 max_regions)
2520 {
2521         struct o2hb_region *reg;
2522         int numregs = 0;
2523         char *p;
2524
2525         spin_lock(&o2hb_live_lock);
2526
2527         p = region_uuids;
2528         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2529                 if (reg->hr_item_dropped)
2530                         continue;
2531
2532                 mlog(0, "Region: %s\n", config_item_name(&reg->hr_item));
2533                 if (numregs < max_regions) {
2534                         memcpy(p, config_item_name(&reg->hr_item),
2535                                O2HB_MAX_REGION_NAME_LEN);
2536                         p += O2HB_MAX_REGION_NAME_LEN;
2537                 }
2538                 numregs++;
2539         }
2540
2541         spin_unlock(&o2hb_live_lock);
2542
2543         return numregs;
2544 }
2545 EXPORT_SYMBOL_GPL(o2hb_get_all_regions);
2546
2547 int o2hb_global_heartbeat_active(void)
2548 {
2549         return (o2hb_heartbeat_mode == O2HB_HEARTBEAT_GLOBAL);
2550 }
2551 EXPORT_SYMBOL(o2hb_global_heartbeat_active);