fs/ocfs2/cluster/heartbeat.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* -*- mode: c; c-basic-offset: 8; -*-
   3  * vim: noexpandtab sw=8 ts=8 sts=0:
   4  *
   5  * Copyright (C) 2004, 2005 Oracle.  All rights reserved.
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/sched.h>
  10 #include <linux/jiffies.h>
  11 #include <linux/module.h>
  12 #include <linux/fs.h>
  13 #include <linux/bio.h>
  14 #include <linux/blkdev.h>
  15 #include <linux/delay.h>
  16 #include <linux/file.h>
  17 #include <linux/kthread.h>
  18 #include <linux/configfs.h>
  19 #include <linux/random.h>
  20 #include <linux/crc32.h>
  21 #include <linux/time.h>
  22 #include <linux/debugfs.h>
  23 #include <linux/slab.h>
  24 #include <linux/bitmap.h>
  25 #include <linux/ktime.h>
  26 #include "heartbeat.h"
  27 #include "tcp.h"
  28 #include "nodemanager.h"
  29 #include "quorum.h"
  30
  31 #include "masklog.h"
  32
  33
  34 /*
  35  * The first heartbeat pass had one global thread that would serialize all hb
  36  * callback calls.  This global serializing sem should only be removed once
  37  * we've made sure that all callees can deal with being called concurrently
  38  * from multiple hb region threads.
  39  */
  40 static DECLARE_RWSEM(o2hb_callback_sem);
  41
  42 /*
  43  * multiple hb threads are watching multiple regions.  A node is live
  44  * whenever any of the threads sees activity from the node in its region.
  45  */
  46 static DEFINE_SPINLOCK(o2hb_live_lock);
  47 static struct list_head o2hb_live_slots[O2NM_MAX_NODES];
  48 static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
  49 static LIST_HEAD(o2hb_node_events);
  50 static DECLARE_WAIT_QUEUE_HEAD(o2hb_steady_queue);
  51
  52 /*
  53  * In global heartbeat, we maintain a series of region bitmaps.
  54  *      - o2hb_region_bitmap allows us to limit the region number to max region.
  55  *      - o2hb_live_region_bitmap tracks live regions (seen steady iterations).
  56  *      - o2hb_quorum_region_bitmap tracks live regions that have seen all nodes
  57  *              heartbeat on it.
  58  *      - o2hb_failed_region_bitmap tracks the regions that have seen io timeouts.
  59  */
  60 static unsigned long o2hb_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  61 static unsigned long o2hb_live_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  62 static unsigned long o2hb_quorum_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  63 static unsigned long o2hb_failed_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  64
  65 #define O2HB_DB_TYPE_LIVENODES          0
  66 #define O2HB_DB_TYPE_LIVEREGIONS        1
  67 #define O2HB_DB_TYPE_QUORUMREGIONS      2
  68 #define O2HB_DB_TYPE_FAILEDREGIONS      3
  69 #define O2HB_DB_TYPE_REGION_LIVENODES   4
  70 #define O2HB_DB_TYPE_REGION_NUMBER      5
  71 #define O2HB_DB_TYPE_REGION_ELAPSED_TIME        6
  72 #define O2HB_DB_TYPE_REGION_PINNED      7
  73 struct o2hb_debug_buf {
  74         int db_type;
  75         int db_size;
  76         int db_len;
  77         void *db_data;
  78 };
  79
  80 static struct o2hb_debug_buf *o2hb_db_livenodes;
  81 static struct o2hb_debug_buf *o2hb_db_liveregions;
  82 static struct o2hb_debug_buf *o2hb_db_quorumregions;
  83 static struct o2hb_debug_buf *o2hb_db_failedregions;
  84
  85 #define O2HB_DEBUG_DIR                  "o2hb"
  86 #define O2HB_DEBUG_LIVENODES            "livenodes"
  87 #define O2HB_DEBUG_LIVEREGIONS          "live_regions"
  88 #define O2HB_DEBUG_QUORUMREGIONS        "quorum_regions"
  89 #define O2HB_DEBUG_FAILEDREGIONS        "failed_regions"
  90 #define O2HB_DEBUG_REGION_NUMBER        "num"
  91 #define O2HB_DEBUG_REGION_ELAPSED_TIME  "elapsed_time_in_ms"
  92 #define O2HB_DEBUG_REGION_PINNED        "pinned"
  93
  94 static struct dentry *o2hb_debug_dir;
  95
  96 static LIST_HEAD(o2hb_all_regions);
  97
  98 static struct o2hb_callback {
  99         struct list_head list;
 100 } o2hb_callbacks[O2HB_NUM_CB];
 101
 102 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type);
 103
 104 enum o2hb_heartbeat_modes {
 105         O2HB_HEARTBEAT_LOCAL            = 0,
 106         O2HB_HEARTBEAT_GLOBAL,
 107         O2HB_HEARTBEAT_NUM_MODES,
 108 };
 109
 110 static const char *o2hb_heartbeat_mode_desc[O2HB_HEARTBEAT_NUM_MODES] = {
 111         "local",        /* O2HB_HEARTBEAT_LOCAL */
 112         "global",       /* O2HB_HEARTBEAT_GLOBAL */
 113 };
 114
 115 unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
 116 static unsigned int o2hb_heartbeat_mode = O2HB_HEARTBEAT_LOCAL;
 117
 118 /*
 119  * o2hb_dependent_users tracks the number of registered callbacks that depend
 120  * on heartbeat. o2net and o2dlm are two entities that register this callback.
 121  * However only o2dlm depends on the heartbeat. It does not want the heartbeat
 122  * to stop while a dlm domain is still active.
 123  */
 124 static unsigned int o2hb_dependent_users;
 125
 126 /*
 127  * In global heartbeat mode, all regions are pinned if there are one or more
 128  * dependent users and the quorum region count is <= O2HB_PIN_CUT_OFF. All
 129  * regions are unpinned if the region count exceeds the cut off or the number
 130  * of dependent users falls to zero.
 131  */
 132 #define O2HB_PIN_CUT_OFF                3
 133
 134 /*
 135  * In local heartbeat mode, we assume the dlm domain name to be the same as
 136  * region uuid. This is true for domains created for the file system but not
 137  * necessarily true for userdlm domains. This is a known limitation.
 138  *
 139  * In global heartbeat mode, we pin/unpin all o2hb regions. This solution
 140  * works for both file system and userdlm domains.
 141  */
 142 static int o2hb_region_pin(const char *region_uuid);
 143 static void o2hb_region_unpin(const char *region_uuid);
 144
 145 /* Only sets a new threshold if there are no active regions.
 146  *
 147  * No locking or otherwise interesting code is required for reading
 148  * o2hb_dead_threshold as it can't change once regions are active and
 149  * it's not interesting to anyone until then anyway. */
 150 static void o2hb_dead_threshold_set(unsigned int threshold)
 151 {
 152         if (threshold > O2HB_MIN_DEAD_THRESHOLD) {
 153                 spin_lock(&o2hb_live_lock);
 154                 if (list_empty(&o2hb_all_regions))
 155                         o2hb_dead_threshold = threshold;
 156                 spin_unlock(&o2hb_live_lock);
 157         }
 158 }
 159
 160 static int o2hb_global_heartbeat_mode_set(unsigned int hb_mode)
 161 {
 162         int ret = -1;
 163
 164         if (hb_mode < O2HB_HEARTBEAT_NUM_MODES) {
 165                 spin_lock(&o2hb_live_lock);
 166                 if (list_empty(&o2hb_all_regions)) {
 167                         o2hb_heartbeat_mode = hb_mode;
 168                         ret = 0;
 169                 }
 170                 spin_unlock(&o2hb_live_lock);
 171         }
 172
 173         return ret;
 174 }
 175
 176 struct o2hb_node_event {
 177         struct list_head        hn_item;
 178         enum o2hb_callback_type hn_event_type;
 179         struct o2nm_node        *hn_node;
 180         int                     hn_node_num;
 181 };
 182
 183 struct o2hb_disk_slot {
 184         struct o2hb_disk_heartbeat_block *ds_raw_block;
 185         u8                      ds_node_num;
 186         u64                     ds_last_time;
 187         u64                     ds_last_generation;
 188         u16                     ds_equal_samples;
 189         u16                     ds_changed_samples;
 190         struct list_head        ds_live_item;
 191 };
 192
 193 /* each thread owns a region.. when we're asked to tear down the region
 194  * we ask the thread to stop, who cleans up the region */
 195 struct o2hb_region {
 196         struct config_item      hr_item;
 197
 198         struct list_head        hr_all_item;
 199         unsigned                hr_unclean_stop:1,
 200                                 hr_aborted_start:1,
 201                                 hr_item_pinned:1,
 202                                 hr_item_dropped:1,
 203                                 hr_node_deleted:1;
 204
 205         /* protected by the hr_callback_sem */
 206         struct task_struct      *hr_task;
 207
 208         unsigned int            hr_blocks;
 209         unsigned long long      hr_start_block;
 210
 211         unsigned int            hr_block_bits;
 212         unsigned int            hr_block_bytes;
 213
 214         unsigned int            hr_slots_per_page;
 215         unsigned int            hr_num_pages;
 216
 217         struct page             **hr_slot_data;
 218         struct block_device     *hr_bdev;
 219         struct o2hb_disk_slot   *hr_slots;
 220
 221         /* live node map of this region */
 222         unsigned long           hr_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 223         unsigned int            hr_region_num;
 224
 225         struct dentry           *hr_debug_dir;
 226         struct o2hb_debug_buf   *hr_db_livenodes;
 227         struct o2hb_debug_buf   *hr_db_regnum;
 228         struct o2hb_debug_buf   *hr_db_elapsed_time;
 229         struct o2hb_debug_buf   *hr_db_pinned;
 230
 231         /* let the person setting up hb wait for it to return until it
 232          * has reached a 'steady' state.  This will be fixed when we have
 233          * a more complete api that doesn't lead to this sort of fragility. */
 234         atomic_t                hr_steady_iterations;
 235
 236         /* terminate o2hb thread if it does not reach steady state
 237          * (hr_steady_iterations == 0) within hr_unsteady_iterations */
 238         atomic_t                hr_unsteady_iterations;
 239
 240         char                    hr_dev_name[BDEVNAME_SIZE];
 241
 242         unsigned int            hr_timeout_ms;
 243
 244         /* randomized as the region goes up and down so that a node
 245          * recognizes a node going up and down in one iteration */
 246         u64                     hr_generation;
 247
 248         struct delayed_work     hr_write_timeout_work;
 249         unsigned long           hr_last_timeout_start;
 250
 251         /* negotiate timer, used to negotiate extending hb timeout. */
 252         struct delayed_work     hr_nego_timeout_work;
 253         unsigned long           hr_nego_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 254
 255         /* Used during o2hb_check_slot to hold a copy of the block
 256          * being checked because we temporarily have to zero out the
 257          * crc field. */
 258         struct o2hb_disk_heartbeat_block *hr_tmp_block;
 259
 260         /* Message key for negotiate timeout message. */
 261         unsigned int            hr_key;
 262         struct list_head        hr_handler_list;
 263
 264         /* last hb status, 0 for success, other value for error. */
 265         int                     hr_last_hb_status;
 266 };
 267
 268 struct o2hb_bio_wait_ctxt {
 269         atomic_t          wc_num_reqs;
 270         struct completion wc_io_complete;
 271         int               wc_error;
 272 };
 273
 274 #define O2HB_NEGO_TIMEOUT_MS (O2HB_MAX_WRITE_TIMEOUT_MS/2)
 275
 276 enum {
 277         O2HB_NEGO_TIMEOUT_MSG = 1,
 278         O2HB_NEGO_APPROVE_MSG = 2,
 279 };
 280
 281 struct o2hb_nego_msg {
 282         u8 node_num;
 283 };
 284
 285 static void o2hb_write_timeout(struct work_struct *work)
 286 {
 287         int failed, quorum;
 288         struct o2hb_region *reg =
 289                 container_of(work, struct o2hb_region,
 290                              hr_write_timeout_work.work);
 291
 292         mlog(ML_ERROR, "Heartbeat write timeout to device %s after %u "
 293              "milliseconds\n", reg->hr_dev_name,
 294              jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
 295
 296         if (o2hb_global_heartbeat_active()) {
 297                 spin_lock(&o2hb_live_lock);
 298                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 299                         set_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 300                 failed = bitmap_weight(o2hb_failed_region_bitmap,
 301                                         O2NM_MAX_REGIONS);
 302                 quorum = bitmap_weight(o2hb_quorum_region_bitmap,
 303                                         O2NM_MAX_REGIONS);
 304                 spin_unlock(&o2hb_live_lock);
 305
 306                 mlog(ML_HEARTBEAT, "Number of regions %d, failed regions %d\n",
 307                      quorum, failed);
 308
 309                 /*
 310                  * Fence if the number of failed regions >= half the number
 311                  * of  quorum regions
 312                  */
 313                 if ((failed << 1) < quorum)
 314                         return;
 315         }
 316
 317         o2quo_disk_timeout();
 318 }
 319
 320 static void o2hb_arm_timeout(struct o2hb_region *reg)
 321 {
 322         /* Arm writeout only after thread reaches steady state */
 323         if (atomic_read(&reg->hr_steady_iterations) != 0)
 324                 return;
 325
 326         mlog(ML_HEARTBEAT, "Queue write timeout for %u ms\n",
 327              O2HB_MAX_WRITE_TIMEOUT_MS);
 328
 329         if (o2hb_global_heartbeat_active()) {
 330                 spin_lock(&o2hb_live_lock);
 331                 clear_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 332                 spin_unlock(&o2hb_live_lock);
 333         }
 334         cancel_delayed_work(&reg->hr_write_timeout_work);
 335         schedule_delayed_work(&reg->hr_write_timeout_work,
 336                               msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
 337
 338         cancel_delayed_work(&reg->hr_nego_timeout_work);
 339         /* negotiate timeout must be less than write timeout. */
 340         schedule_delayed_work(&reg->hr_nego_timeout_work,
 341                               msecs_to_jiffies(O2HB_NEGO_TIMEOUT_MS));
 342         memset(reg->hr_nego_node_bitmap, 0, sizeof(reg->hr_nego_node_bitmap));
 343 }
 344
 345 static void o2hb_disarm_timeout(struct o2hb_region *reg)
 346 {
 347         cancel_delayed_work_sync(&reg->hr_write_timeout_work);
 348         cancel_delayed_work_sync(&reg->hr_nego_timeout_work);
 349 }
 350
 351 static int o2hb_send_nego_msg(int key, int type, u8 target)
 352 {
 353         struct o2hb_nego_msg msg;
 354         int status, ret;
 355
 356         msg.node_num = o2nm_this_node();
 357 again:
 358         ret = o2net_send_message(type, key, &msg, sizeof(msg),
 359                         target, &status);
 360
 361         if (ret == -EAGAIN || ret == -ENOMEM) {
 362                 msleep(100);
 363                 goto again;
 364         }
 365
 366         return ret;
 367 }
 368
 369 static void o2hb_nego_timeout(struct work_struct *work)
 370 {
 371         unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 372         int master_node, i, ret;
 373         struct o2hb_region *reg;
 374
 375         reg = container_of(work, struct o2hb_region, hr_nego_timeout_work.work);
 376         /* don't negotiate timeout if last hb failed since it is very
 377          * possible io failed. Should let write timeout fence self.
 378          */
 379         if (reg->hr_last_hb_status)
 380                 return;
 381
 382         o2hb_fill_node_map(live_node_bitmap, sizeof(live_node_bitmap));
 383         /* lowest node as master node to make negotiate decision. */
 384         master_node = find_next_bit(live_node_bitmap, O2NM_MAX_NODES, 0);
 385
 386         if (master_node == o2nm_this_node()) {
 387                 if (!test_bit(master_node, reg->hr_nego_node_bitmap)) {
 388                         printk(KERN_NOTICE "o2hb: node %d hb write hung for %ds on region %s (%s).\n",
 389                                 o2nm_this_node(), O2HB_NEGO_TIMEOUT_MS/1000,
 390                                 config_item_name(&reg->hr_item), reg->hr_dev_name);
 391                         set_bit(master_node, reg->hr_nego_node_bitmap);
 392                 }
 393                 if (memcmp(reg->hr_nego_node_bitmap, live_node_bitmap,
 394                                 sizeof(reg->hr_nego_node_bitmap))) {
 395                         /* check negotiate bitmap every second to do timeout
 396                          * approve decision.
 397                          */
 398                         schedule_delayed_work(&reg->hr_nego_timeout_work,
 399                                 msecs_to_jiffies(1000));
 400
 401                         return;
 402                 }
 403
 404                 printk(KERN_NOTICE "o2hb: all nodes hb write hung, maybe region %s (%s) is down.\n",
 405                         config_item_name(&reg->hr_item), reg->hr_dev_name);
 406                 /* approve negotiate timeout request. */
 407                 o2hb_arm_timeout(reg);
 408
 409                 i = -1;
 410                 while ((i = find_next_bit(live_node_bitmap,
 411                                 O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
 412                         if (i == master_node)
 413                                 continue;
 414
 415                         mlog(ML_HEARTBEAT, "send NEGO_APPROVE msg to node %d\n", i);
 416                         ret = o2hb_send_nego_msg(reg->hr_key,
 417                                         O2HB_NEGO_APPROVE_MSG, i);
 418                         if (ret)
 419                                 mlog(ML_ERROR, "send NEGO_APPROVE msg to node %d fail %d\n",
 420                                         i, ret);
 421                 }
 422         } else {
 423                 /* negotiate timeout with master node. */
 424                 printk(KERN_NOTICE "o2hb: node %d hb write hung for %ds on region %s (%s), negotiate timeout with node %d.\n",
 425                         o2nm_this_node(), O2HB_NEGO_TIMEOUT_MS/1000, config_item_name(&reg->hr_item),
 426                         reg->hr_dev_name, master_node);
 427                 ret = o2hb_send_nego_msg(reg->hr_key, O2HB_NEGO_TIMEOUT_MSG,
 428                                 master_node);
 429                 if (ret)
 430                         mlog(ML_ERROR, "send NEGO_TIMEOUT msg to node %d fail %d\n",
 431                                 master_node, ret);
 432         }
 433 }
 434
 435 static int o2hb_nego_timeout_handler(struct o2net_msg *msg, u32 len, void *data,
 436                                 void **ret_data)
 437 {
 438         struct o2hb_region *reg = data;
 439         struct o2hb_nego_msg *nego_msg;
 440
 441         nego_msg = (struct o2hb_nego_msg *)msg->buf;
 442         printk(KERN_NOTICE "o2hb: receive negotiate timeout message from node %d on region %s (%s).\n",
 443                 nego_msg->node_num, config_item_name(&reg->hr_item), reg->hr_dev_name);
 444         if (nego_msg->node_num < O2NM_MAX_NODES)
 445                 set_bit(nego_msg->node_num, reg->hr_nego_node_bitmap);
 446         else
 447                 mlog(ML_ERROR, "got nego timeout message from bad node.\n");
 448
 449         return 0;
 450 }
 451
 452 static int o2hb_nego_approve_handler(struct o2net_msg *msg, u32 len, void *data,
 453                                 void **ret_data)
 454 {
 455         struct o2hb_region *reg = data;
 456
 457         printk(KERN_NOTICE "o2hb: negotiate timeout approved by master node on region %s (%s).\n",
 458                 config_item_name(&reg->hr_item), reg->hr_dev_name);
 459         o2hb_arm_timeout(reg);
 460         return 0;
 461 }
 462
 463 static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
 464 {
 465         atomic_set(&wc->wc_num_reqs, 1);
 466         init_completion(&wc->wc_io_complete);
 467         wc->wc_error = 0;
 468 }
 469
 470 /* Used in error paths too */
 471 static inline void o2hb_bio_wait_dec(struct o2hb_bio_wait_ctxt *wc,
 472                                      unsigned int num)
 473 {
 474         /* sadly atomic_sub_and_test() isn't available on all platforms.  The
 475          * good news is that the fast path only completes one at a time */
 476         while(num--) {
 477                 if (atomic_dec_and_test(&wc->wc_num_reqs)) {
 478                         BUG_ON(num > 0);
 479                         complete(&wc->wc_io_complete);
 480                 }
 481         }
 482 }
 483
 484 static void o2hb_wait_on_io(struct o2hb_bio_wait_ctxt *wc)
 485 {
 486         o2hb_bio_wait_dec(wc, 1);
 487         wait_for_completion(&wc->wc_io_complete);
 488 }
 489
 490 static void o2hb_bio_end_io(struct bio *bio)
 491 {
 492         struct o2hb_bio_wait_ctxt *wc = bio->bi_private;
 493
 494         if (bio->bi_status) {
 495                 mlog(ML_ERROR, "IO Error %d\n", bio->bi_status);
 496                 wc->wc_error = blk_status_to_errno(bio->bi_status);
 497         }
 498
 499         o2hb_bio_wait_dec(wc, 1);
 500         bio_put(bio);
 501 }
 502
 503 /* Setup a Bio to cover I/O against num_slots slots starting at
 504  * start_slot. */
 505 static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
 506                                       struct o2hb_bio_wait_ctxt *wc,
 507                                       unsigned int *current_slot,
 508                                       unsigned int max_slots, int op,
 509                                       int op_flags)
 510 {
 511         int len, current_page;
 512         unsigned int vec_len, vec_start;
 513         unsigned int bits = reg->hr_block_bits;
 514         unsigned int spp = reg->hr_slots_per_page;
 515         unsigned int cs = *current_slot;
 516         struct bio *bio;
 517         struct page *page;
 518
 519         /* Testing has shown this allocation to take long enough under
 520          * GFP_KERNEL that the local node can get fenced. It would be
 521          * nicest if we could pre-allocate these bios and avoid this
 522          * all together. */
 523         bio = bio_alloc(GFP_ATOMIC, 16);
 524         if (!bio) {
 525                 mlog(ML_ERROR, "Could not alloc slots BIO!\n");
 526                 bio = ERR_PTR(-ENOMEM);
 527                 goto bail;
 528         }
 529
 530         /* Must put everything in 512 byte sectors for the bio... */
 531         bio->bi_iter.bi_sector = (reg->hr_start_block + cs) << (bits - 9);
 532         bio_set_dev(bio, reg->hr_bdev);
 533         bio->bi_private = wc;
 534         bio->bi_end_io = o2hb_bio_end_io;
 535         bio_set_op_attrs(bio, op, op_flags);
 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, 0);
 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, REQ_OP_WRITE,
 606                                  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 (%s): expected(%u:0x%llx, 0x%llx), "
 697              "ondisk(%u:0x%llx, 0x%llx)\n", errstr, reg->hr_dev_name,
 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 (memcmp(reg->hr_live_node_bitmap, o2hb_live_node_bitmap,
 867                    sizeof(o2hb_live_node_bitmap)))
 868                 goto unlock;
 869
 870         printk(KERN_NOTICE "o2hb: Region %s (%s) is now a quorum device\n",
 871                config_item_name(&reg->hr_item), reg->hr_dev_name);
 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 %s\n",
 930                      slot->ds_node_num, reg->hr_dev_name);
 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 %s 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->hr_dev_name, slot_dead_ms,
1014                              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, sizeof(live_node_bitmap));
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 \"%s\"\n",
1153                      write_wc.wc_error, reg->hr_dev_name);
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 (%s)\n",
1178                                config_item_name(&reg->hr_item),
1179                                reg->hr_dev_name);
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         INIT_LIST_HEAD(&o2hb_node_events);
1448
1449         memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
1450         memset(o2hb_region_bitmap, 0, sizeof(o2hb_region_bitmap));
1451         memset(o2hb_live_region_bitmap, 0, sizeof(o2hb_live_region_bitmap));
1452         memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
1453         memset(o2hb_failed_region_bitmap, 0, sizeof(o2hb_failed_region_bitmap));
1454
1455         o2hb_dependent_users = 0;
1456
1457         o2hb_debug_init();
1458 }
1459
1460 /* if we're already in a callback then we're already serialized by the sem */
1461 static void o2hb_fill_node_map_from_callback(unsigned long *map,
1462                                              unsigned bytes)
1463 {
1464         BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1465
1466         memcpy(map, &o2hb_live_node_bitmap, bytes);
1467 }
1468
1469 /*
1470  * get a map of all nodes that are heartbeating in any regions
1471  */
1472 void o2hb_fill_node_map(unsigned long *map, unsigned bytes)
1473 {
1474         /* callers want to serialize this map and callbacks so that they
1475          * can trust that they don't miss nodes coming to the party */
1476         down_read(&o2hb_callback_sem);
1477         spin_lock(&o2hb_live_lock);
1478         o2hb_fill_node_map_from_callback(map, bytes);
1479         spin_unlock(&o2hb_live_lock);
1480         up_read(&o2hb_callback_sem);
1481 }
1482 EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
1483
1484 /*
1485  * heartbeat configfs bits.  The heartbeat set is a default set under
1486  * the cluster set in nodemanager.c.
1487  */
1488
1489 static struct o2hb_region *to_o2hb_region(struct config_item *item)
1490 {
1491         return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
1492 }
1493
1494 /* drop_item only drops its ref after killing the thread, nothing should
1495  * be using the region anymore.  this has to clean up any state that
1496  * attributes might have built up. */
1497 static void o2hb_region_release(struct config_item *item)
1498 {
1499         int i;
1500         struct page *page;
1501         struct o2hb_region *reg = to_o2hb_region(item);
1502
1503         mlog(ML_HEARTBEAT, "hb region release (%s)\n", reg->hr_dev_name);
1504
1505         kfree(reg->hr_tmp_block);
1506
1507         if (reg->hr_slot_data) {
1508                 for (i = 0; i < reg->hr_num_pages; i++) {
1509                         page = reg->hr_slot_data[i];
1510                         if (page)
1511                                 __free_page(page);
1512                 }
1513                 kfree(reg->hr_slot_data);
1514         }
1515
1516         if (reg->hr_bdev)
1517                 blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1518
1519         kfree(reg->hr_slots);
1520
1521         debugfs_remove_recursive(reg->hr_debug_dir);
1522         kfree(reg->hr_db_livenodes);
1523         kfree(reg->hr_db_regnum);
1524         kfree(reg->hr_db_elapsed_time);
1525         kfree(reg->hr_db_pinned);
1526
1527         spin_lock(&o2hb_live_lock);
1528         list_del(&reg->hr_all_item);
1529         spin_unlock(&o2hb_live_lock);
1530
1531         o2net_unregister_handler_list(&reg->hr_handler_list);
1532         kfree(reg);
1533 }
1534
1535 static int o2hb_read_block_input(struct o2hb_region *reg,
1536                                  const char *page,
1537                                  unsigned long *ret_bytes,
1538                                  unsigned int *ret_bits)
1539 {
1540         unsigned long bytes;
1541         char *p = (char *)page;
1542
1543         bytes = simple_strtoul(p, &p, 0);
1544         if (!p || (*p && (*p != '\n')))
1545                 return -EINVAL;
1546
1547         /* Heartbeat and fs min / max block sizes are the same. */
1548         if (bytes > 4096 || bytes < 512)
1549                 return -ERANGE;
1550         if (hweight16(bytes) != 1)
1551                 return -EINVAL;
1552
1553         if (ret_bytes)
1554                 *ret_bytes = bytes;
1555         if (ret_bits)
1556                 *ret_bits = ffs(bytes) - 1;
1557
1558         return 0;
1559 }
1560
1561 static ssize_t o2hb_region_block_bytes_show(struct config_item *item,
1562                                             char *page)
1563 {
1564         return sprintf(page, "%u\n", to_o2hb_region(item)->hr_block_bytes);
1565 }
1566
1567 static ssize_t o2hb_region_block_bytes_store(struct config_item *item,
1568                                              const char *page,
1569                                              size_t count)
1570 {
1571         struct o2hb_region *reg = to_o2hb_region(item);
1572         int status;
1573         unsigned long block_bytes;
1574         unsigned int block_bits;
1575
1576         if (reg->hr_bdev)
1577                 return -EINVAL;
1578
1579         status = o2hb_read_block_input(reg, page, &block_bytes,
1580                                        &block_bits);
1581         if (status)
1582                 return status;
1583
1584         reg->hr_block_bytes = (unsigned int)block_bytes;
1585         reg->hr_block_bits = block_bits;
1586
1587         return count;
1588 }
1589
1590 static ssize_t o2hb_region_start_block_show(struct config_item *item,
1591                                             char *page)
1592 {
1593         return sprintf(page, "%llu\n", to_o2hb_region(item)->hr_start_block);
1594 }
1595
1596 static ssize_t o2hb_region_start_block_store(struct config_item *item,
1597                                              const char *page,
1598                                              size_t count)
1599 {
1600         struct o2hb_region *reg = to_o2hb_region(item);
1601         unsigned long long tmp;
1602         char *p = (char *)page;
1603
1604         if (reg->hr_bdev)
1605                 return -EINVAL;
1606
1607         tmp = simple_strtoull(p, &p, 0);
1608         if (!p || (*p && (*p != '\n')))
1609                 return -EINVAL;
1610
1611         reg->hr_start_block = tmp;
1612
1613         return count;
1614 }
1615
1616 static ssize_t o2hb_region_blocks_show(struct config_item *item, char *page)
1617 {
1618         return sprintf(page, "%d\n", to_o2hb_region(item)->hr_blocks);
1619 }
1620
1621 static ssize_t o2hb_region_blocks_store(struct config_item *item,
1622                                         const char *page,
1623                                         size_t count)
1624 {
1625         struct o2hb_region *reg = to_o2hb_region(item);
1626         unsigned long tmp;
1627         char *p = (char *)page;
1628
1629         if (reg->hr_bdev)
1630                 return -EINVAL;
1631
1632         tmp = simple_strtoul(p, &p, 0);
1633         if (!p || (*p && (*p != '\n')))
1634                 return -EINVAL;
1635
1636         if (tmp > O2NM_MAX_NODES || tmp == 0)
1637                 return -ERANGE;
1638
1639         reg->hr_blocks = (unsigned int)tmp;
1640
1641         return count;
1642 }
1643
1644 static ssize_t o2hb_region_dev_show(struct config_item *item, char *page)
1645 {
1646         unsigned int ret = 0;
1647
1648         if (to_o2hb_region(item)->hr_bdev)
1649                 ret = sprintf(page, "%s\n", to_o2hb_region(item)->hr_dev_name);
1650
1651         return ret;
1652 }
1653
1654 static void o2hb_init_region_params(struct o2hb_region *reg)
1655 {
1656         reg->hr_slots_per_page = PAGE_SIZE >> reg->hr_block_bits;
1657         reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
1658
1659         mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
1660              reg->hr_start_block, reg->hr_blocks);
1661         mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
1662              reg->hr_block_bytes, reg->hr_block_bits);
1663         mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
1664         mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
1665 }
1666
1667 static int o2hb_map_slot_data(struct o2hb_region *reg)
1668 {
1669         int i, j;
1670         unsigned int last_slot;
1671         unsigned int spp = reg->hr_slots_per_page;
1672         struct page *page;
1673         char *raw;
1674         struct o2hb_disk_slot *slot;
1675
1676         reg->hr_tmp_block = kmalloc(reg->hr_block_bytes, GFP_KERNEL);
1677         if (reg->hr_tmp_block == NULL)
1678                 return -ENOMEM;
1679
1680         reg->hr_slots = kcalloc(reg->hr_blocks,
1681                                 sizeof(struct o2hb_disk_slot), GFP_KERNEL);
1682         if (reg->hr_slots == NULL)
1683                 return -ENOMEM;
1684
1685         for(i = 0; i < reg->hr_blocks; i++) {
1686                 slot = &reg->hr_slots[i];
1687                 slot->ds_node_num = i;
1688                 INIT_LIST_HEAD(&slot->ds_live_item);
1689                 slot->ds_raw_block = NULL;
1690         }
1691
1692         reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
1693         mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
1694                            "at %u blocks per page\n",
1695              reg->hr_num_pages, reg->hr_blocks, spp);
1696
1697         reg->hr_slot_data = kcalloc(reg->hr_num_pages, sizeof(struct page *),
1698                                     GFP_KERNEL);
1699         if (!reg->hr_slot_data)
1700                 return -ENOMEM;
1701
1702         for(i = 0; i < reg->hr_num_pages; i++) {
1703                 page = alloc_page(GFP_KERNEL);
1704                 if (!page)
1705                         return -ENOMEM;
1706
1707                 reg->hr_slot_data[i] = page;
1708
1709                 last_slot = i * spp;
1710                 raw = page_address(page);
1711                 for (j = 0;
1712                      (j < spp) && ((j + last_slot) < reg->hr_blocks);
1713                      j++) {
1714                         BUG_ON((j + last_slot) >= reg->hr_blocks);
1715
1716                         slot = &reg->hr_slots[j + last_slot];
1717                         slot->ds_raw_block =
1718                                 (struct o2hb_disk_heartbeat_block *) raw;
1719
1720                         raw += reg->hr_block_bytes;
1721                 }
1722         }
1723
1724         return 0;
1725 }
1726
1727 /* Read in all the slots available and populate the tracking
1728  * structures so that we can start with a baseline idea of what's
1729  * there. */
1730 static int o2hb_populate_slot_data(struct o2hb_region *reg)
1731 {
1732         int ret, i;
1733         struct o2hb_disk_slot *slot;
1734         struct o2hb_disk_heartbeat_block *hb_block;
1735
1736         ret = o2hb_read_slots(reg, 0, reg->hr_blocks);
1737         if (ret)
1738                 goto out;
1739
1740         /* We only want to get an idea of the values initially in each
1741          * slot, so we do no verification - o2hb_check_slot will
1742          * actually determine if each configured slot is valid and
1743          * whether any values have changed. */
1744         for(i = 0; i < reg->hr_blocks; i++) {
1745                 slot = &reg->hr_slots[i];
1746                 hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
1747
1748                 /* Only fill the values that o2hb_check_slot uses to
1749                  * determine changing slots */
1750                 slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
1751                 slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
1752         }
1753
1754 out:
1755         return ret;
1756 }
1757
1758 /* this is acting as commit; we set up all of hr_bdev and hr_task or nothing */
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)
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 = blkdev_get_by_dev(f.file->f_mapping->host->i_rdev,
1799                                          FMODE_WRITE | FMODE_READ, NULL);
1800         if (IS_ERR(reg->hr_bdev)) {
1801                 ret = PTR_ERR(reg->hr_bdev);
1802                 reg->hr_bdev = NULL;
1803                 goto out2;
1804         }
1805
1806         bdevname(reg->hr_bdev, reg->hr_dev_name);
1807
1808         sectsize = bdev_logical_block_size(reg->hr_bdev);
1809         if (sectsize != reg->hr_block_bytes) {
1810                 mlog(ML_ERROR,
1811                      "blocksize %u incorrect for device, expected %d",
1812                      reg->hr_block_bytes, sectsize);
1813                 ret = -EINVAL;
1814                 goto out3;
1815         }
1816
1817         o2hb_init_region_params(reg);
1818
1819         /* Generation of zero is invalid */
1820         do {
1821                 get_random_bytes(&reg->hr_generation,
1822                                  sizeof(reg->hr_generation));
1823         } while (reg->hr_generation == 0);
1824
1825         ret = o2hb_map_slot_data(reg);
1826         if (ret) {
1827                 mlog_errno(ret);
1828                 goto out3;
1829         }
1830
1831         ret = o2hb_populate_slot_data(reg);
1832         if (ret) {
1833                 mlog_errno(ret);
1834                 goto out3;
1835         }
1836
1837         INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
1838         INIT_DELAYED_WORK(&reg->hr_nego_timeout_work, o2hb_nego_timeout);
1839
1840         /*
1841          * A node is considered live after it has beat LIVE_THRESHOLD
1842          * times.  We're not steady until we've given them a chance
1843          * _after_ our first read.
1844          * The default threshold is bare minimum so as to limit the delay
1845          * during mounts. For global heartbeat, the threshold doubled for the
1846          * first region.
1847          */
1848         live_threshold = O2HB_LIVE_THRESHOLD;
1849         if (o2hb_global_heartbeat_active()) {
1850                 spin_lock(&o2hb_live_lock);
1851                 if (bitmap_weight(o2hb_region_bitmap, O2NM_MAX_REGIONS) == 1)
1852                         live_threshold <<= 1;
1853                 spin_unlock(&o2hb_live_lock);
1854         }
1855         ++live_threshold;
1856         atomic_set(&reg->hr_steady_iterations, live_threshold);
1857         /* unsteady_iterations is triple the steady_iterations */
1858         atomic_set(&reg->hr_unsteady_iterations, (live_threshold * 3));
1859
1860         hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
1861                               reg->hr_item.ci_name);
1862         if (IS_ERR(hb_task)) {
1863                 ret = PTR_ERR(hb_task);
1864                 mlog_errno(ret);
1865                 goto out3;
1866         }
1867
1868         spin_lock(&o2hb_live_lock);
1869         reg->hr_task = hb_task;
1870         spin_unlock(&o2hb_live_lock);
1871
1872         ret = wait_event_interruptible(o2hb_steady_queue,
1873                                 atomic_read(&reg->hr_steady_iterations) == 0 ||
1874                                 reg->hr_node_deleted);
1875         if (ret) {
1876                 atomic_set(&reg->hr_steady_iterations, 0);
1877                 reg->hr_aborted_start = 1;
1878         }
1879
1880         if (reg->hr_aborted_start) {
1881                 ret = -EIO;
1882                 goto out3;
1883         }
1884
1885         if (reg->hr_node_deleted) {
1886                 ret = -EINVAL;
1887                 goto out3;
1888         }
1889
1890         /* Ok, we were woken.  Make sure it wasn't by drop_item() */
1891         spin_lock(&o2hb_live_lock);
1892         hb_task = reg->hr_task;
1893         if (o2hb_global_heartbeat_active())
1894                 set_bit(reg->hr_region_num, o2hb_live_region_bitmap);
1895         spin_unlock(&o2hb_live_lock);
1896
1897         if (hb_task)
1898                 ret = count;
1899         else
1900                 ret = -EIO;
1901
1902         if (hb_task && o2hb_global_heartbeat_active())
1903                 printk(KERN_NOTICE "o2hb: Heartbeat started on region %s (%s)\n",
1904                        config_item_name(&reg->hr_item), reg->hr_dev_name);
1905
1906 out3:
1907         if (ret < 0) {
1908                 blkdev_put(reg->hr_bdev, FMODE_READ | FMODE_WRITE);
1909                 reg->hr_bdev = NULL;
1910         }
1911 out2:
1912         fdput(f);
1913 out:
1914         return ret;
1915 }
1916
1917 static ssize_t o2hb_region_pid_show(struct config_item *item, char *page)
1918 {
1919         struct o2hb_region *reg = to_o2hb_region(item);
1920         pid_t pid = 0;
1921
1922         spin_lock(&o2hb_live_lock);
1923         if (reg->hr_task)
1924                 pid = task_pid_nr(reg->hr_task);
1925         spin_unlock(&o2hb_live_lock);
1926
1927         if (!pid)
1928                 return 0;
1929
1930         return sprintf(page, "%u\n", pid);
1931 }
1932
1933 CONFIGFS_ATTR(o2hb_region_, block_bytes);
1934 CONFIGFS_ATTR(o2hb_region_, start_block);
1935 CONFIGFS_ATTR(o2hb_region_, blocks);
1936 CONFIGFS_ATTR(o2hb_region_, dev);
1937 CONFIGFS_ATTR_RO(o2hb_region_, pid);
1938
1939 static struct configfs_attribute *o2hb_region_attrs[] = {
1940         &o2hb_region_attr_block_bytes,
1941         &o2hb_region_attr_start_block,
1942         &o2hb_region_attr_blocks,
1943         &o2hb_region_attr_dev,
1944         &o2hb_region_attr_pid,
1945         NULL,
1946 };
1947
1948 static struct configfs_item_operations o2hb_region_item_ops = {
1949         .release                = o2hb_region_release,
1950 };
1951
1952 static const struct config_item_type o2hb_region_type = {
1953         .ct_item_ops    = &o2hb_region_item_ops,
1954         .ct_attrs       = o2hb_region_attrs,
1955         .ct_owner       = THIS_MODULE,
1956 };
1957
1958 /* heartbeat set */
1959
1960 struct o2hb_heartbeat_group {
1961         struct config_group hs_group;
1962         /* some stuff? */
1963 };
1964
1965 static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
1966 {
1967         return group ?
1968                 container_of(group, struct o2hb_heartbeat_group, hs_group)
1969                 : NULL;
1970 }
1971
1972 static void o2hb_debug_region_init(struct o2hb_region *reg,
1973                                    struct dentry *parent)
1974 {
1975         struct dentry *dir;
1976
1977         dir = debugfs_create_dir(config_item_name(&reg->hr_item), parent);
1978         reg->hr_debug_dir = dir;
1979
1980         o2hb_debug_create(O2HB_DEBUG_LIVENODES, dir, &(reg->hr_db_livenodes),
1981                           sizeof(*(reg->hr_db_livenodes)),
1982                           O2HB_DB_TYPE_REGION_LIVENODES,
1983                           sizeof(reg->hr_live_node_bitmap), O2NM_MAX_NODES,
1984                           reg);
1985
1986         o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER, dir, &(reg->hr_db_regnum),
1987                           sizeof(*(reg->hr_db_regnum)),
1988                           O2HB_DB_TYPE_REGION_NUMBER, 0, O2NM_MAX_NODES, reg);
1989
1990         o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME, dir,
1991                           &(reg->hr_db_elapsed_time),
1992                           sizeof(*(reg->hr_db_elapsed_time)),
1993                           O2HB_DB_TYPE_REGION_ELAPSED_TIME, 0, 0, reg);
1994
1995         o2hb_debug_create(O2HB_DEBUG_REGION_PINNED, dir, &(reg->hr_db_pinned),
1996                           sizeof(*(reg->hr_db_pinned)),
1997                           O2HB_DB_TYPE_REGION_PINNED, 0, 0, reg);
1998
1999 }
2000
2001 static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
2002                                                           const char *name)
2003 {
2004         struct o2hb_region *reg = NULL;
2005         int ret;
2006
2007         reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
2008         if (reg == NULL)
2009                 return ERR_PTR(-ENOMEM);
2010
2011         if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
2012                 ret = -ENAMETOOLONG;
2013                 goto free;
2014         }
2015
2016         spin_lock(&o2hb_live_lock);
2017         reg->hr_region_num = 0;
2018         if (o2hb_global_heartbeat_active()) {
2019                 reg->hr_region_num = find_first_zero_bit(o2hb_region_bitmap,
2020                                                          O2NM_MAX_REGIONS);
2021                 if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
2022                         spin_unlock(&o2hb_live_lock);
2023                         ret = -EFBIG;
2024                         goto free;
2025                 }
2026                 set_bit(reg->hr_region_num, o2hb_region_bitmap);
2027         }
2028         list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
2029         spin_unlock(&o2hb_live_lock);
2030
2031         config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
2032
2033         /* this is the same way to generate msg key as dlm, for local heartbeat,
2034          * name is also the same, so make initial crc value different to avoid
2035          * message key conflict.
2036          */
2037         reg->hr_key = crc32_le(reg->hr_region_num + O2NM_MAX_REGIONS,
2038                 name, strlen(name));
2039         INIT_LIST_HEAD(&reg->hr_handler_list);
2040         ret = o2net_register_handler(O2HB_NEGO_TIMEOUT_MSG, reg->hr_key,
2041                         sizeof(struct o2hb_nego_msg),
2042                         o2hb_nego_timeout_handler,
2043                         reg, NULL, &reg->hr_handler_list);
2044         if (ret)
2045                 goto free;
2046
2047         ret = o2net_register_handler(O2HB_NEGO_APPROVE_MSG, reg->hr_key,
2048                         sizeof(struct o2hb_nego_msg),
2049                         o2hb_nego_approve_handler,
2050                         reg, NULL, &reg->hr_handler_list);
2051         if (ret)
2052                 goto unregister_handler;
2053
2054         o2hb_debug_region_init(reg, o2hb_debug_dir);
2055
2056         return &reg->hr_item;
2057
2058 unregister_handler:
2059         o2net_unregister_handler_list(&reg->hr_handler_list);
2060 free:
2061         kfree(reg);
2062         return ERR_PTR(ret);
2063 }
2064
2065 static void o2hb_heartbeat_group_drop_item(struct config_group *group,
2066                                            struct config_item *item)
2067 {
2068         struct task_struct *hb_task;
2069         struct o2hb_region *reg = to_o2hb_region(item);
2070         int quorum_region = 0;
2071
2072         /* stop the thread when the user removes the region dir */
2073         spin_lock(&o2hb_live_lock);
2074         hb_task = reg->hr_task;
2075         reg->hr_task = NULL;
2076         reg->hr_item_dropped = 1;
2077         spin_unlock(&o2hb_live_lock);
2078
2079         if (hb_task)
2080                 kthread_stop(hb_task);
2081
2082         if (o2hb_global_heartbeat_active()) {
2083                 spin_lock(&o2hb_live_lock);
2084                 clear_bit(reg->hr_region_num, o2hb_region_bitmap);
2085                 clear_bit(reg->hr_region_num, o2hb_live_region_bitmap);
2086                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
2087                         quorum_region = 1;
2088                 clear_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
2089                 spin_unlock(&o2hb_live_lock);
2090                 printk(KERN_NOTICE "o2hb: Heartbeat %s on region %s (%s)\n",
2091                        ((atomic_read(&reg->hr_steady_iterations) == 0) ?
2092                         "stopped" : "start aborted"), config_item_name(item),
2093                        reg->hr_dev_name);
2094         }
2095
2096         /*
2097          * If we're racing a dev_write(), we need to wake them.  They will
2098          * check reg->hr_task
2099          */
2100         if (atomic_read(&reg->hr_steady_iterations) != 0) {
2101                 reg->hr_aborted_start = 1;
2102                 atomic_set(&reg->hr_steady_iterations, 0);
2103                 wake_up(&o2hb_steady_queue);
2104         }
2105
2106         config_item_put(item);
2107
2108         if (!o2hb_global_heartbeat_active() || !quorum_region)
2109                 return;
2110
2111         /*
2112          * If global heartbeat active and there are dependent users,
2113          * pin all regions if quorum region count <= CUT_OFF
2114          */
2115         spin_lock(&o2hb_live_lock);
2116
2117         if (!o2hb_dependent_users)
2118                 goto unlock;
2119
2120         if (bitmap_weight(o2hb_quorum_region_bitmap,
2121                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2122                 o2hb_region_pin(NULL);
2123
2124 unlock:
2125         spin_unlock(&o2hb_live_lock);
2126 }
2127
2128 static ssize_t o2hb_heartbeat_group_dead_threshold_show(struct config_item *item,
2129                 char *page)
2130 {
2131         return sprintf(page, "%u\n", o2hb_dead_threshold);
2132 }
2133
2134 static ssize_t o2hb_heartbeat_group_dead_threshold_store(struct config_item *item,
2135                 const char *page, size_t count)
2136 {
2137         unsigned long tmp;
2138         char *p = (char *)page;
2139
2140         tmp = simple_strtoul(p, &p, 10);
2141         if (!p || (*p && (*p != '\n')))
2142                 return -EINVAL;
2143
2144         /* this will validate ranges for us. */
2145         o2hb_dead_threshold_set((unsigned int) tmp);
2146
2147         return count;
2148 }
2149
2150 static ssize_t o2hb_heartbeat_group_mode_show(struct config_item *item,
2151                 char *page)
2152 {
2153         return sprintf(page, "%s\n",
2154                        o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
2155 }
2156
2157 static ssize_t o2hb_heartbeat_group_mode_store(struct config_item *item,
2158                 const char *page, size_t count)
2159 {
2160         unsigned int i;
2161         int ret;
2162         size_t len;
2163
2164         len = (page[count - 1] == '\n') ? count - 1 : count;
2165         if (!len)
2166                 return -EINVAL;
2167
2168         for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
2169                 if (strncasecmp(page, o2hb_heartbeat_mode_desc[i], len))
2170                         continue;
2171
2172                 ret = o2hb_global_heartbeat_mode_set(i);
2173                 if (!ret)
2174                         printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
2175                                o2hb_heartbeat_mode_desc[i]);
2176                 return count;
2177         }
2178
2179         return -EINVAL;
2180
2181 }
2182
2183 CONFIGFS_ATTR(o2hb_heartbeat_group_, dead_threshold);
2184 CONFIGFS_ATTR(o2hb_heartbeat_group_, mode);
2185
2186 static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
2187         &o2hb_heartbeat_group_attr_dead_threshold,
2188         &o2hb_heartbeat_group_attr_mode,
2189         NULL,
2190 };
2191
2192 static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
2193         .make_item      = o2hb_heartbeat_group_make_item,
2194         .drop_item      = o2hb_heartbeat_group_drop_item,
2195 };
2196
2197 static const struct config_item_type o2hb_heartbeat_group_type = {
2198         .ct_group_ops   = &o2hb_heartbeat_group_group_ops,
2199         .ct_attrs       = o2hb_heartbeat_group_attrs,
2200         .ct_owner       = THIS_MODULE,
2201 };
2202
2203 /* this is just here to avoid touching group in heartbeat.h which the
2204  * entire damn world #includes */
2205 struct config_group *o2hb_alloc_hb_set(void)
2206 {
2207         struct o2hb_heartbeat_group *hs = NULL;
2208         struct config_group *ret = NULL;
2209
2210         hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
2211         if (hs == NULL)
2212                 goto out;
2213
2214         config_group_init_type_name(&hs->hs_group, "heartbeat",
2215                                     &o2hb_heartbeat_group_type);
2216
2217         ret = &hs->hs_group;
2218 out:
2219         if (ret == NULL)
2220                 kfree(hs);
2221         return ret;
2222 }
2223
2224 void o2hb_free_hb_set(struct config_group *group)
2225 {
2226         struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
2227         kfree(hs);
2228 }
2229
2230 /* hb callback registration and issuing */
2231
2232 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
2233 {
2234         if (type == O2HB_NUM_CB)
2235                 return ERR_PTR(-EINVAL);
2236
2237         return &o2hb_callbacks[type];
2238 }
2239
2240 void o2hb_setup_callback(struct o2hb_callback_func *hc,
2241                          enum o2hb_callback_type type,
2242                          o2hb_cb_func *func,
2243                          void *data,
2244                          int priority)
2245 {
2246         INIT_LIST_HEAD(&hc->hc_item);
2247         hc->hc_func = func;
2248         hc->hc_data = data;
2249         hc->hc_priority = priority;
2250         hc->hc_type = type;
2251         hc->hc_magic = O2HB_CB_MAGIC;
2252 }
2253 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
2254
2255 /*
2256  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2257  * In global heartbeat mode, region_uuid passed is NULL.
2258  *
2259  * In local, we only pin the matching region. In global we pin all the active
2260  * regions.
2261  */
2262 static int o2hb_region_pin(const char *region_uuid)
2263 {
2264         int ret = 0, found = 0;
2265         struct o2hb_region *reg;
2266         char *uuid;
2267
2268         assert_spin_locked(&o2hb_live_lock);
2269
2270         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2271                 if (reg->hr_item_dropped)
2272                         continue;
2273
2274                 uuid = config_item_name(&reg->hr_item);
2275
2276                 /* local heartbeat */
2277                 if (region_uuid) {
2278                         if (strcmp(region_uuid, uuid))
2279                                 continue;
2280                         found = 1;
2281                 }
2282
2283                 if (reg->hr_item_pinned || reg->hr_item_dropped)
2284                         goto skip_pin;
2285
2286                 /* Ignore ENOENT only for local hb (userdlm domain) */
2287                 ret = o2nm_depend_item(&reg->hr_item);
2288                 if (!ret) {
2289                         mlog(ML_CLUSTER, "Pin region %s\n", uuid);
2290                         reg->hr_item_pinned = 1;
2291                 } else {
2292                         if (ret == -ENOENT && found)
2293                                 ret = 0;
2294                         else {
2295                                 mlog(ML_ERROR, "Pin region %s fails with %d\n",
2296                                      uuid, ret);
2297                                 break;
2298                         }
2299                 }
2300 skip_pin:
2301                 if (found)
2302                         break;
2303         }
2304
2305         return ret;
2306 }
2307
2308 /*
2309  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2310  * In global heartbeat mode, region_uuid passed is NULL.
2311  *
2312  * In local, we only unpin the matching region. In global we unpin all the
2313  * active regions.
2314  */
2315 static void o2hb_region_unpin(const char *region_uuid)
2316 {
2317         struct o2hb_region *reg;
2318         char *uuid;
2319         int found = 0;
2320
2321         assert_spin_locked(&o2hb_live_lock);
2322
2323         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2324                 if (reg->hr_item_dropped)
2325                         continue;
2326
2327                 uuid = config_item_name(&reg->hr_item);
2328                 if (region_uuid) {
2329                         if (strcmp(region_uuid, uuid))
2330                                 continue;
2331                         found = 1;
2332                 }
2333
2334                 if (reg->hr_item_pinned) {
2335                         mlog(ML_CLUSTER, "Unpin region %s\n", uuid);
2336                         o2nm_undepend_item(&reg->hr_item);
2337                         reg->hr_item_pinned = 0;
2338                 }
2339                 if (found)
2340                         break;
2341         }
2342 }
2343
2344 static int o2hb_region_inc_user(const char *region_uuid)
2345 {
2346         int ret = 0;
2347
2348         spin_lock(&o2hb_live_lock);
2349
2350         /* local heartbeat */
2351         if (!o2hb_global_heartbeat_active()) {
2352             ret = o2hb_region_pin(region_uuid);
2353             goto unlock;
2354         }
2355
2356         /*
2357          * if global heartbeat active and this is the first dependent user,
2358          * pin all regions if quorum region count <= CUT_OFF
2359          */
2360         o2hb_dependent_users++;
2361         if (o2hb_dependent_users > 1)
2362                 goto unlock;
2363
2364         if (bitmap_weight(o2hb_quorum_region_bitmap,
2365                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2366                 ret = o2hb_region_pin(NULL);
2367
2368 unlock:
2369         spin_unlock(&o2hb_live_lock);
2370         return ret;
2371 }
2372
2373 static void o2hb_region_dec_user(const char *region_uuid)
2374 {
2375         spin_lock(&o2hb_live_lock);
2376
2377         /* local heartbeat */
2378         if (!o2hb_global_heartbeat_active()) {
2379             o2hb_region_unpin(region_uuid);
2380             goto unlock;
2381         }
2382
2383         /*
2384          * if global heartbeat active and there are no dependent users,
2385          * unpin all quorum regions
2386          */
2387         o2hb_dependent_users--;
2388         if (!o2hb_dependent_users)
2389                 o2hb_region_unpin(NULL);
2390
2391 unlock:
2392         spin_unlock(&o2hb_live_lock);
2393 }
2394
2395 int o2hb_register_callback(const char *region_uuid,
2396                            struct o2hb_callback_func *hc)
2397 {
2398         struct o2hb_callback_func *f;
2399         struct o2hb_callback *hbcall;
2400         int ret;
2401
2402         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2403         BUG_ON(!list_empty(&hc->hc_item));
2404
2405         hbcall = hbcall_from_type(hc->hc_type);
2406         if (IS_ERR(hbcall)) {
2407                 ret = PTR_ERR(hbcall);
2408                 goto out;
2409         }
2410
2411         if (region_uuid) {
2412                 ret = o2hb_region_inc_user(region_uuid);
2413                 if (ret) {
2414                         mlog_errno(ret);
2415                         goto out;
2416                 }
2417         }
2418
2419         down_write(&o2hb_callback_sem);
2420
2421         list_for_each_entry(f, &hbcall->list, hc_item) {
2422                 if (hc->hc_priority < f->hc_priority) {
2423                         list_add_tail(&hc->hc_item, &f->hc_item);
2424                         break;
2425                 }
2426         }
2427         if (list_empty(&hc->hc_item))
2428                 list_add_tail(&hc->hc_item, &hbcall->list);
2429
2430         up_write(&o2hb_callback_sem);
2431         ret = 0;
2432 out:
2433         mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
2434              ret, __builtin_return_address(0), hc);
2435         return ret;
2436 }
2437 EXPORT_SYMBOL_GPL(o2hb_register_callback);
2438
2439 void o2hb_unregister_callback(const char *region_uuid,
2440                               struct o2hb_callback_func *hc)
2441 {
2442         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2443
2444         mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
2445              __builtin_return_address(0), hc);
2446
2447         /* XXX Can this happen _with_ a region reference? */
2448         if (list_empty(&hc->hc_item))
2449                 return;
2450
2451         if (region_uuid)
2452                 o2hb_region_dec_user(region_uuid);
2453
2454         down_write(&o2hb_callback_sem);
2455
2456         list_del_init(&hc->hc_item);
2457
2458         up_write(&o2hb_callback_sem);
2459 }
2460 EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
2461
2462 int o2hb_check_node_heartbeating_no_sem(u8 node_num)
2463 {
2464         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2465
2466         spin_lock(&o2hb_live_lock);
2467         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2468         spin_unlock(&o2hb_live_lock);
2469         if (!test_bit(node_num, testing_map)) {
2470                 mlog(ML_HEARTBEAT,
2471                      "node (%u) does not have heartbeating enabled.\n",
2472                      node_num);
2473                 return 0;
2474         }
2475
2476         return 1;
2477 }
2478 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_no_sem);
2479
2480 int o2hb_check_node_heartbeating_from_callback(u8 node_num)
2481 {
2482         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2483
2484         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2485         if (!test_bit(node_num, testing_map)) {
2486                 mlog(ML_HEARTBEAT,
2487                      "node (%u) does not have heartbeating enabled.\n",
2488                      node_num);
2489                 return 0;
2490         }
2491
2492         return 1;
2493 }
2494 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_from_callback);
2495
2496 /*
2497  * this is just a hack until we get the plumbing which flips file systems
2498  * read only and drops the hb ref instead of killing the node dead.
2499  */
2500 void o2hb_stop_all_regions(void)
2501 {
2502         struct o2hb_region *reg;
2503
2504         mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");
2505
2506         spin_lock(&o2hb_live_lock);
2507
2508         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
2509                 reg->hr_unclean_stop = 1;
2510
2511         spin_unlock(&o2hb_live_lock);
2512 }
2513 EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
2514
2515 int o2hb_get_all_regions(char *region_uuids, u8 max_regions)
2516 {
2517         struct o2hb_region *reg;
2518         int numregs = 0;
2519         char *p;
2520
2521         spin_lock(&o2hb_live_lock);
2522
2523         p = region_uuids;
2524         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2525                 if (reg->hr_item_dropped)
2526                         continue;
2527
2528                 mlog(0, "Region: %s\n", config_item_name(&reg->hr_item));
2529                 if (numregs < max_regions) {
2530                         memcpy(p, config_item_name(&reg->hr_item),
2531                                O2HB_MAX_REGION_NAME_LEN);
2532                         p += O2HB_MAX_REGION_NAME_LEN;
2533                 }
2534                 numregs++;
2535         }
2536
2537         spin_unlock(&o2hb_live_lock);
2538
2539         return numregs;
2540 }
2541 EXPORT_SYMBOL_GPL(o2hb_get_all_regions);
2542
2543 int o2hb_global_heartbeat_active(void)
2544 {
2545         return (o2hb_heartbeat_mode == O2HB_HEARTBEAT_GLOBAL);
2546 }
2547 EXPORT_SYMBOL(o2hb_global_heartbeat_active);