fs/ocfs2/cluster/heartbeat.c

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