fs/ocfs2/cluster/heartbeat.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * Copyright (C) 2004, 2005 Oracle.  All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public
  17  * License along with this program; if not, write to the
  18  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19  * Boston, MA 021110-1307, USA.
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/sched.h>
  24 #include <linux/jiffies.h>
  25 #include <linux/module.h>
  26 #include <linux/fs.h>
  27 #include <linux/bio.h>
  28 #include <linux/blkdev.h>
  29 #include <linux/delay.h>
  30 #include <linux/file.h>
  31 #include <linux/kthread.h>
  32 #include <linux/configfs.h>
  33 #include <linux/random.h>
  34 #include <linux/crc32.h>
  35 #include <linux/time.h>
  36 #include <linux/debugfs.h>
  37 #include <linux/slab.h>
  38 #include <linux/bitmap.h>
  39 #include <linux/ktime.h>
  40 #include "heartbeat.h"
  41 #include "tcp.h"
  42 #include "nodemanager.h"
  43 #include "quorum.h"
  44
  45 #include "masklog.h"
  46
  47
  48 /*
  49  * The first heartbeat pass had one global thread that would serialize all hb
  50  * callback calls.  This global serializing sem should only be removed once
  51  * we've made sure that all callees can deal with being called concurrently
  52  * from multiple hb region threads.
  53  */
  54 static DECLARE_RWSEM(o2hb_callback_sem);
  55
  56 /*
  57  * multiple hb threads are watching multiple regions.  A node is live
  58  * whenever any of the threads sees activity from the node in its region.
  59  */
  60 static DEFINE_SPINLOCK(o2hb_live_lock);
  61 static struct list_head o2hb_live_slots[O2NM_MAX_NODES];
  62 static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
  63 static LIST_HEAD(o2hb_node_events);
  64 static DECLARE_WAIT_QUEUE_HEAD(o2hb_steady_queue);
  65
  66 /*
  67  * In global heartbeat, we maintain a series of region bitmaps.
  68  *      - o2hb_region_bitmap allows us to limit the region number to max region.
  69  *      - o2hb_live_region_bitmap tracks live regions (seen steady iterations).
  70  *      - o2hb_quorum_region_bitmap tracks live regions that have seen all nodes
  71  *              heartbeat on it.
  72  *      - o2hb_failed_region_bitmap tracks the regions that have seen io timeouts.
  73  */
  74 static unsigned long o2hb_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  75 static unsigned long o2hb_live_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  76 static unsigned long o2hb_quorum_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  77 static unsigned long o2hb_failed_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  78
  79 #define O2HB_DB_TYPE_LIVENODES          0
  80 #define O2HB_DB_TYPE_LIVEREGIONS        1
  81 #define O2HB_DB_TYPE_QUORUMREGIONS      2
  82 #define O2HB_DB_TYPE_FAILEDREGIONS      3
  83 #define O2HB_DB_TYPE_REGION_LIVENODES   4
  84 #define O2HB_DB_TYPE_REGION_NUMBER      5
  85 #define O2HB_DB_TYPE_REGION_ELAPSED_TIME        6
  86 #define O2HB_DB_TYPE_REGION_PINNED      7
  87 struct o2hb_debug_buf {
  88         int db_type;
  89         int db_size;
  90         int db_len;
  91         void *db_data;
  92 };
  93
  94 static struct o2hb_debug_buf *o2hb_db_livenodes;
  95 static struct o2hb_debug_buf *o2hb_db_liveregions;
  96 static struct o2hb_debug_buf *o2hb_db_quorumregions;
  97 static struct o2hb_debug_buf *o2hb_db_failedregions;
  98
  99 #define O2HB_DEBUG_DIR                  "o2hb"
 100 #define O2HB_DEBUG_LIVENODES            "livenodes"
 101 #define O2HB_DEBUG_LIVEREGIONS          "live_regions"
 102 #define O2HB_DEBUG_QUORUMREGIONS        "quorum_regions"
 103 #define O2HB_DEBUG_FAILEDREGIONS        "failed_regions"
 104 #define O2HB_DEBUG_REGION_NUMBER        "num"
 105 #define O2HB_DEBUG_REGION_ELAPSED_TIME  "elapsed_time_in_ms"
 106 #define O2HB_DEBUG_REGION_PINNED        "pinned"
 107
 108 static struct dentry *o2hb_debug_dir;
 109 static struct dentry *o2hb_debug_livenodes;
 110 static struct dentry *o2hb_debug_liveregions;
 111 static struct dentry *o2hb_debug_quorumregions;
 112 static struct dentry *o2hb_debug_failedregions;
 113
 114 static LIST_HEAD(o2hb_all_regions);
 115
 116 static struct o2hb_callback {
 117         struct list_head list;
 118 } o2hb_callbacks[O2HB_NUM_CB];
 119
 120 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type);
 121
 122 #define O2HB_DEFAULT_BLOCK_BITS       9
 123
 124 enum o2hb_heartbeat_modes {
 125         O2HB_HEARTBEAT_LOCAL            = 0,
 126         O2HB_HEARTBEAT_GLOBAL,
 127         O2HB_HEARTBEAT_NUM_MODES,
 128 };
 129
 130 char *o2hb_heartbeat_mode_desc[O2HB_HEARTBEAT_NUM_MODES] = {
 131                 "local",        /* O2HB_HEARTBEAT_LOCAL */
 132                 "global",       /* O2HB_HEARTBEAT_GLOBAL */
 133 };
 134
 135 unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
 136 unsigned int o2hb_heartbeat_mode = O2HB_HEARTBEAT_LOCAL;
 137
 138 /*
 139  * o2hb_dependent_users tracks the number of registered callbacks that depend
 140  * on heartbeat. o2net and o2dlm are two entities that register this callback.
 141  * However only o2dlm depends on the heartbeat. It does not want the heartbeat
 142  * to stop while a dlm domain is still active.
 143  */
 144 unsigned int o2hb_dependent_users;
 145
 146 /*
 147  * In global heartbeat mode, all regions are pinned if there are one or more
 148  * dependent users and the quorum region count is <= O2HB_PIN_CUT_OFF. All
 149  * regions are unpinned if the region count exceeds the cut off or the number
 150  * of dependent users falls to zero.
 151  */
 152 #define O2HB_PIN_CUT_OFF                3
 153
 154 /*
 155  * In local heartbeat mode, we assume the dlm domain name to be the same as
 156  * region uuid. This is true for domains created for the file system but not
 157  * necessarily true for userdlm domains. This is a known limitation.
 158  *
 159  * In global heartbeat mode, we pin/unpin all o2hb regions. This solution
 160  * works for both file system and userdlm domains.
 161  */
 162 static int o2hb_region_pin(const char *region_uuid);
 163 static void o2hb_region_unpin(const char *region_uuid);
 164
 165 /* Only sets a new threshold if there are no active regions.
 166  *
 167  * No locking or otherwise interesting code is required for reading
 168  * o2hb_dead_threshold as it can't change once regions are active and
 169  * it's not interesting to anyone until then anyway. */
 170 static void o2hb_dead_threshold_set(unsigned int threshold)
 171 {
 172         if (threshold > O2HB_MIN_DEAD_THRESHOLD) {
 173                 spin_lock(&o2hb_live_lock);
 174                 if (list_empty(&o2hb_all_regions))
 175                         o2hb_dead_threshold = threshold;
 176                 spin_unlock(&o2hb_live_lock);
 177         }
 178 }
 179
 180 static int o2hb_global_heartbeat_mode_set(unsigned int hb_mode)
 181 {
 182         int ret = -1;
 183
 184         if (hb_mode < O2HB_HEARTBEAT_NUM_MODES) {
 185                 spin_lock(&o2hb_live_lock);
 186                 if (list_empty(&o2hb_all_regions)) {
 187                         o2hb_heartbeat_mode = hb_mode;
 188                         ret = 0;
 189                 }
 190                 spin_unlock(&o2hb_live_lock);
 191         }
 192
 193         return ret;
 194 }
 195
 196 struct o2hb_node_event {
 197         struct list_head        hn_item;
 198         enum o2hb_callback_type hn_event_type;
 199         struct o2nm_node        *hn_node;
 200         int                     hn_node_num;
 201 };
 202
 203 struct o2hb_disk_slot {
 204         struct o2hb_disk_heartbeat_block *ds_raw_block;
 205         u8                      ds_node_num;
 206         u64                     ds_last_time;
 207         u64                     ds_last_generation;
 208         u16                     ds_equal_samples;
 209         u16                     ds_changed_samples;
 210         struct list_head        ds_live_item;
 211 };
 212
 213 /* each thread owns a region.. when we're asked to tear down the region
 214  * we ask the thread to stop, who cleans up the region */
 215 struct o2hb_region {
 216         struct config_item      hr_item;
 217
 218         struct list_head        hr_all_item;
 219         unsigned                hr_unclean_stop:1,
 220                                 hr_aborted_start:1,
 221                                 hr_item_pinned:1,
 222                                 hr_item_dropped:1,
 223                                 hr_node_deleted:1;
 224
 225         /* protected by the hr_callback_sem */
 226         struct task_struct      *hr_task;
 227
 228         unsigned int            hr_blocks;
 229         unsigned long long      hr_start_block;
 230
 231         unsigned int            hr_block_bits;
 232         unsigned int            hr_block_bytes;
 233
 234         unsigned int            hr_slots_per_page;
 235         unsigned int            hr_num_pages;
 236
 237         struct page             **hr_slot_data;
 238         struct block_device     *hr_bdev;
 239         struct o2hb_disk_slot   *hr_slots;
 240
 241         /* live node map of this region */
 242         unsigned long           hr_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 243         unsigned int            hr_region_num;
 244
 245         struct dentry           *hr_debug_dir;
 246         struct dentry           *hr_debug_livenodes;
 247         struct dentry           *hr_debug_regnum;
 248         struct dentry           *hr_debug_elapsed_time;
 249         struct dentry           *hr_debug_pinned;
 250         struct o2hb_debug_buf   *hr_db_livenodes;
 251         struct o2hb_debug_buf   *hr_db_regnum;
 252         struct o2hb_debug_buf   *hr_db_elapsed_time;
 253         struct o2hb_debug_buf   *hr_db_pinned;
 254
 255         /* let the person setting up hb wait for it to return until it
 256          * has reached a 'steady' state.  This will be fixed when we have
 257          * a more complete api that doesn't lead to this sort of fragility. */
 258         atomic_t                hr_steady_iterations;
 259
 260         /* terminate o2hb thread if it does not reach steady state
 261          * (hr_steady_iterations == 0) within hr_unsteady_iterations */
 262         atomic_t                hr_unsteady_iterations;
 263
 264         char                    hr_dev_name[BDEVNAME_SIZE];
 265
 266         unsigned int            hr_timeout_ms;
 267
 268         /* randomized as the region goes up and down so that a node
 269          * recognizes a node going up and down in one iteration */
 270         u64                     hr_generation;
 271
 272         struct delayed_work     hr_write_timeout_work;
 273         unsigned long           hr_last_timeout_start;
 274
 275         /* negotiate timer, used to negotiate extending hb timeout. */
 276         struct delayed_work     hr_nego_timeout_work;
 277         unsigned long           hr_nego_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 278
 279         /* Used during o2hb_check_slot to hold a copy of the block
 280          * being checked because we temporarily have to zero out the
 281          * crc field. */
 282         struct o2hb_disk_heartbeat_block *hr_tmp_block;
 283
 284         /* Message key for negotiate timeout message. */
 285         unsigned int            hr_key;
 286         struct list_head        hr_handler_list;
 287 };
 288
 289 struct o2hb_bio_wait_ctxt {
 290         atomic_t          wc_num_reqs;
 291         struct completion wc_io_complete;
 292         int               wc_error;
 293 };
 294
 295 enum {
 296         O2HB_NEGO_TIMEOUT_MSG = 1,
 297 };
 298
 299 struct o2hb_nego_msg {
 300         u8 node_num;
 301 };
 302
 303 static void o2hb_write_timeout(struct work_struct *work)
 304 {
 305         int failed, quorum;
 306         struct o2hb_region *reg =
 307                 container_of(work, struct o2hb_region,
 308                              hr_write_timeout_work.work);
 309
 310         mlog(ML_ERROR, "Heartbeat write timeout to device %s after %u "
 311              "milliseconds\n", reg->hr_dev_name,
 312              jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
 313
 314         if (o2hb_global_heartbeat_active()) {
 315                 spin_lock(&o2hb_live_lock);
 316                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 317                         set_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 318                 failed = bitmap_weight(o2hb_failed_region_bitmap,
 319                                         O2NM_MAX_REGIONS);
 320                 quorum = bitmap_weight(o2hb_quorum_region_bitmap,
 321                                         O2NM_MAX_REGIONS);
 322                 spin_unlock(&o2hb_live_lock);
 323
 324                 mlog(ML_HEARTBEAT, "Number of regions %d, failed regions %d\n",
 325                      quorum, failed);
 326
 327                 /*
 328                  * Fence if the number of failed regions >= half the number
 329                  * of  quorum regions
 330                  */
 331                 if ((failed << 1) < quorum)
 332                         return;
 333         }
 334
 335         o2quo_disk_timeout();
 336 }
 337
 338 static void o2hb_arm_timeout(struct o2hb_region *reg)
 339 {
 340         /* Arm writeout only after thread reaches steady state */
 341         if (atomic_read(&reg->hr_steady_iterations) != 0)
 342                 return;
 343
 344         mlog(ML_HEARTBEAT, "Queue write timeout for %u ms\n",
 345              O2HB_MAX_WRITE_TIMEOUT_MS);
 346
 347         if (o2hb_global_heartbeat_active()) {
 348                 spin_lock(&o2hb_live_lock);
 349                 clear_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 350                 spin_unlock(&o2hb_live_lock);
 351         }
 352         cancel_delayed_work(&reg->hr_write_timeout_work);
 353         reg->hr_last_timeout_start = jiffies;
 354         schedule_delayed_work(&reg->hr_write_timeout_work,
 355                               msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
 356
 357         cancel_delayed_work(&reg->hr_nego_timeout_work);
 358         /* negotiate timeout must be less than write timeout. */
 359         schedule_delayed_work(&reg->hr_nego_timeout_work,
 360                               msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS)/2);
 361         memset(reg->hr_nego_node_bitmap, 0, sizeof(reg->hr_nego_node_bitmap));
 362 }
 363
 364 static void o2hb_disarm_timeout(struct o2hb_region *reg)
 365 {
 366         cancel_delayed_work_sync(&reg->hr_write_timeout_work);
 367         cancel_delayed_work_sync(&reg->hr_nego_timeout_work);
 368 }
 369
 370 static int o2hb_send_nego_msg(int key, int type, u8 target)
 371 {
 372         struct o2hb_nego_msg msg;
 373         int status, ret;
 374
 375         msg.node_num = o2nm_this_node();
 376 again:
 377         ret = o2net_send_message(type, key, &msg, sizeof(msg),
 378                         target, &status);
 379
 380         if (ret == -EAGAIN || ret == -ENOMEM) {
 381                 msleep(100);
 382                 goto again;
 383         }
 384
 385         return ret;
 386 }
 387
 388 static void o2hb_nego_timeout(struct work_struct *work)
 389 {
 390         unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 391         int master_node;
 392         struct o2hb_region *reg;
 393
 394         reg = container_of(work, struct o2hb_region, hr_nego_timeout_work.work);
 395         o2hb_fill_node_map(live_node_bitmap, sizeof(live_node_bitmap));
 396         /* lowest node as master node to make negotiate decision. */
 397         master_node = find_next_bit(live_node_bitmap, O2NM_MAX_NODES, 0);
 398
 399         if (master_node == o2nm_this_node()) {
 400                 set_bit(master_node, reg->hr_nego_node_bitmap);
 401                 if (memcmp(reg->hr_nego_node_bitmap, live_node_bitmap,
 402                                 sizeof(reg->hr_nego_node_bitmap))) {
 403                         /* check negotiate bitmap every second to do timeout
 404                          * approve decision.
 405                          */
 406                         schedule_delayed_work(&reg->hr_nego_timeout_work,
 407                                 msecs_to_jiffies(1000));
 408
 409                         return;
 410                 }
 411
 412                 /* approve negotiate timeout request. */
 413         } else {
 414                 /* negotiate timeout with master node. */
 415                 o2hb_send_nego_msg(reg->hr_key, O2HB_NEGO_TIMEOUT_MSG,
 416                         master_node);
 417         }
 418 }
 419
 420 static int o2hb_nego_timeout_handler(struct o2net_msg *msg, u32 len, void *data,
 421                                 void **ret_data)
 422 {
 423         struct o2hb_region *reg = data;
 424         struct o2hb_nego_msg *nego_msg;
 425
 426         nego_msg = (struct o2hb_nego_msg *)msg->buf;
 427         if (nego_msg->node_num < O2NM_MAX_NODES)
 428                 set_bit(nego_msg->node_num, reg->hr_nego_node_bitmap);
 429         else
 430                 mlog(ML_ERROR, "got nego timeout message from bad node.\n");
 431
 432         return 0;
 433 }
 434
 435 static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
 436 {
 437         atomic_set(&wc->wc_num_reqs, 1);
 438         init_completion(&wc->wc_io_complete);
 439         wc->wc_error = 0;
 440 }
 441
 442 /* Used in error paths too */
 443 static inline void o2hb_bio_wait_dec(struct o2hb_bio_wait_ctxt *wc,
 444                                      unsigned int num)
 445 {
 446         /* sadly atomic_sub_and_test() isn't available on all platforms.  The
 447          * good news is that the fast path only completes one at a time */
 448         while(num--) {
 449                 if (atomic_dec_and_test(&wc->wc_num_reqs)) {
 450                         BUG_ON(num > 0);
 451                         complete(&wc->wc_io_complete);
 452                 }
 453         }
 454 }
 455
 456 static void o2hb_wait_on_io(struct o2hb_region *reg,
 457                             struct o2hb_bio_wait_ctxt *wc)
 458 {
 459         o2hb_bio_wait_dec(wc, 1);
 460         wait_for_completion(&wc->wc_io_complete);
 461 }
 462
 463 static void o2hb_bio_end_io(struct bio *bio)
 464 {
 465         struct o2hb_bio_wait_ctxt *wc = bio->bi_private;
 466
 467         if (bio->bi_error) {
 468                 mlog(ML_ERROR, "IO Error %d\n", bio->bi_error);
 469                 wc->wc_error = bio->bi_error;
 470         }
 471
 472         o2hb_bio_wait_dec(wc, 1);
 473         bio_put(bio);
 474 }
 475
 476 /* Setup a Bio to cover I/O against num_slots slots starting at
 477  * start_slot. */
 478 static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
 479                                       struct o2hb_bio_wait_ctxt *wc,
 480                                       unsigned int *current_slot,
 481                                       unsigned int max_slots)
 482 {
 483         int len, current_page;
 484         unsigned int vec_len, vec_start;
 485         unsigned int bits = reg->hr_block_bits;
 486         unsigned int spp = reg->hr_slots_per_page;
 487         unsigned int cs = *current_slot;
 488         struct bio *bio;
 489         struct page *page;
 490
 491         /* Testing has shown this allocation to take long enough under
 492          * GFP_KERNEL that the local node can get fenced. It would be
 493          * nicest if we could pre-allocate these bios and avoid this
 494          * all together. */
 495         bio = bio_alloc(GFP_ATOMIC, 16);
 496         if (!bio) {
 497                 mlog(ML_ERROR, "Could not alloc slots BIO!\n");
 498                 bio = ERR_PTR(-ENOMEM);
 499                 goto bail;
 500         }
 501
 502         /* Must put everything in 512 byte sectors for the bio... */
 503         bio->bi_iter.bi_sector = (reg->hr_start_block + cs) << (bits - 9);
 504         bio->bi_bdev = reg->hr_bdev;
 505         bio->bi_private = wc;
 506         bio->bi_end_io = o2hb_bio_end_io;
 507
 508         vec_start = (cs << bits) % PAGE_SIZE;
 509         while(cs < max_slots) {
 510                 current_page = cs / spp;
 511                 page = reg->hr_slot_data[current_page];
 512
 513                 vec_len = min(PAGE_SIZE - vec_start,
 514                               (max_slots-cs) * (PAGE_SIZE/spp) );
 515
 516                 mlog(ML_HB_BIO, "page %d, vec_len = %u, vec_start = %u\n",
 517                      current_page, vec_len, vec_start);
 518
 519                 len = bio_add_page(bio, page, vec_len, vec_start);
 520                 if (len != vec_len) break;
 521
 522                 cs += vec_len / (PAGE_SIZE/spp);
 523                 vec_start = 0;
 524         }
 525
 526 bail:
 527         *current_slot = cs;
 528         return bio;
 529 }
 530
 531 static int o2hb_read_slots(struct o2hb_region *reg,
 532                            unsigned int max_slots)
 533 {
 534         unsigned int current_slot=0;
 535         int status;
 536         struct o2hb_bio_wait_ctxt wc;
 537         struct bio *bio;
 538
 539         o2hb_bio_wait_init(&wc);
 540
 541         while(current_slot < max_slots) {
 542                 bio = o2hb_setup_one_bio(reg, &wc, &current_slot, max_slots);
 543                 if (IS_ERR(bio)) {
 544                         status = PTR_ERR(bio);
 545                         mlog_errno(status);
 546                         goto bail_and_wait;
 547                 }
 548
 549                 atomic_inc(&wc.wc_num_reqs);
 550                 submit_bio(READ, bio);
 551         }
 552
 553         status = 0;
 554
 555 bail_and_wait:
 556         o2hb_wait_on_io(reg, &wc);
 557         if (wc.wc_error && !status)
 558                 status = wc.wc_error;
 559
 560         return status;
 561 }
 562
 563 static int o2hb_issue_node_write(struct o2hb_region *reg,
 564                                  struct o2hb_bio_wait_ctxt *write_wc)
 565 {
 566         int status;
 567         unsigned int slot;
 568         struct bio *bio;
 569
 570         o2hb_bio_wait_init(write_wc);
 571
 572         slot = o2nm_this_node();
 573
 574         bio = o2hb_setup_one_bio(reg, write_wc, &slot, slot+1);
 575         if (IS_ERR(bio)) {
 576                 status = PTR_ERR(bio);
 577                 mlog_errno(status);
 578                 goto bail;
 579         }
 580
 581         atomic_inc(&write_wc->wc_num_reqs);
 582         submit_bio(WRITE_SYNC, bio);
 583
 584         status = 0;
 585 bail:
 586         return status;
 587 }
 588
 589 static u32 o2hb_compute_block_crc_le(struct o2hb_region *reg,
 590                                      struct o2hb_disk_heartbeat_block *hb_block)
 591 {
 592         __le32 old_cksum;
 593         u32 ret;
 594
 595         /* We want to compute the block crc with a 0 value in the
 596          * hb_cksum field. Save it off here and replace after the
 597          * crc. */
 598         old_cksum = hb_block->hb_cksum;
 599         hb_block->hb_cksum = 0;
 600
 601         ret = crc32_le(0, (unsigned char *) hb_block, reg->hr_block_bytes);
 602
 603         hb_block->hb_cksum = old_cksum;
 604
 605         return ret;
 606 }
 607
 608 static void o2hb_dump_slot(struct o2hb_disk_heartbeat_block *hb_block)
 609 {
 610         mlog(ML_ERROR, "Dump slot information: seq = 0x%llx, node = %u, "
 611              "cksum = 0x%x, generation 0x%llx\n",
 612              (long long)le64_to_cpu(hb_block->hb_seq),
 613              hb_block->hb_node, le32_to_cpu(hb_block->hb_cksum),
 614              (long long)le64_to_cpu(hb_block->hb_generation));
 615 }
 616
 617 static int o2hb_verify_crc(struct o2hb_region *reg,
 618                            struct o2hb_disk_heartbeat_block *hb_block)
 619 {
 620         u32 read, computed;
 621
 622         read = le32_to_cpu(hb_block->hb_cksum);
 623         computed = o2hb_compute_block_crc_le(reg, hb_block);
 624
 625         return read == computed;
 626 }
 627
 628 /*
 629  * Compare the slot data with what we wrote in the last iteration.
 630  * If the match fails, print an appropriate error message. This is to
 631  * detect errors like... another node hearting on the same slot,
 632  * flaky device that is losing writes, etc.
 633  * Returns 1 if check succeeds, 0 otherwise.
 634  */
 635 static int o2hb_check_own_slot(struct o2hb_region *reg)
 636 {
 637         struct o2hb_disk_slot *slot;
 638         struct o2hb_disk_heartbeat_block *hb_block;
 639         char *errstr;
 640
 641         slot = &reg->hr_slots[o2nm_this_node()];
 642         /* Don't check on our 1st timestamp */
 643         if (!slot->ds_last_time)
 644                 return 0;
 645
 646         hb_block = slot->ds_raw_block;
 647         if (le64_to_cpu(hb_block->hb_seq) == slot->ds_last_time &&
 648             le64_to_cpu(hb_block->hb_generation) == slot->ds_last_generation &&
 649             hb_block->hb_node == slot->ds_node_num)
 650                 return 1;
 651
 652 #define ERRSTR1         "Another node is heartbeating on device"
 653 #define ERRSTR2         "Heartbeat generation mismatch on device"
 654 #define ERRSTR3         "Heartbeat sequence mismatch on device"
 655
 656         if (hb_block->hb_node != slot->ds_node_num)
 657                 errstr = ERRSTR1;
 658         else if (le64_to_cpu(hb_block->hb_generation) !=
 659                  slot->ds_last_generation)
 660                 errstr = ERRSTR2;
 661         else
 662                 errstr = ERRSTR3;
 663
 664         mlog(ML_ERROR, "%s (%s): expected(%u:0x%llx, 0x%llx), "
 665              "ondisk(%u:0x%llx, 0x%llx)\n", errstr, reg->hr_dev_name,
 666              slot->ds_node_num, (unsigned long long)slot->ds_last_generation,
 667              (unsigned long long)slot->ds_last_time, hb_block->hb_node,
 668              (unsigned long long)le64_to_cpu(hb_block->hb_generation),
 669              (unsigned long long)le64_to_cpu(hb_block->hb_seq));
 670
 671         return 0;
 672 }
 673
 674 static inline void o2hb_prepare_block(struct o2hb_region *reg,
 675                                       u64 generation)
 676 {
 677         int node_num;
 678         u64 cputime;
 679         struct o2hb_disk_slot *slot;
 680         struct o2hb_disk_heartbeat_block *hb_block;
 681
 682         node_num = o2nm_this_node();
 683         slot = &reg->hr_slots[node_num];
 684
 685         hb_block = (struct o2hb_disk_heartbeat_block *)slot->ds_raw_block;
 686         memset(hb_block, 0, reg->hr_block_bytes);
 687         /* TODO: time stuff */
 688         cputime = CURRENT_TIME.tv_sec;
 689         if (!cputime)
 690                 cputime = 1;
 691
 692         hb_block->hb_seq = cpu_to_le64(cputime);
 693         hb_block->hb_node = node_num;
 694         hb_block->hb_generation = cpu_to_le64(generation);
 695         hb_block->hb_dead_ms = cpu_to_le32(o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS);
 696
 697         /* This step must always happen last! */
 698         hb_block->hb_cksum = cpu_to_le32(o2hb_compute_block_crc_le(reg,
 699                                                                    hb_block));
 700
 701         mlog(ML_HB_BIO, "our node generation = 0x%llx, cksum = 0x%x\n",
 702              (long long)generation,
 703              le32_to_cpu(hb_block->hb_cksum));
 704 }
 705
 706 static void o2hb_fire_callbacks(struct o2hb_callback *hbcall,
 707                                 struct o2nm_node *node,
 708                                 int idx)
 709 {
 710         struct o2hb_callback_func *f;
 711
 712         list_for_each_entry(f, &hbcall->list, hc_item) {
 713                 mlog(ML_HEARTBEAT, "calling funcs %p\n", f);
 714                 (f->hc_func)(node, idx, f->hc_data);
 715         }
 716 }
 717
 718 /* Will run the list in order until we process the passed event */
 719 static void o2hb_run_event_list(struct o2hb_node_event *queued_event)
 720 {
 721         struct o2hb_callback *hbcall;
 722         struct o2hb_node_event *event;
 723
 724         /* Holding callback sem assures we don't alter the callback
 725          * lists when doing this, and serializes ourselves with other
 726          * processes wanting callbacks. */
 727         down_write(&o2hb_callback_sem);
 728
 729         spin_lock(&o2hb_live_lock);
 730         while (!list_empty(&o2hb_node_events)
 731                && !list_empty(&queued_event->hn_item)) {
 732                 event = list_entry(o2hb_node_events.next,
 733                                    struct o2hb_node_event,
 734                                    hn_item);
 735                 list_del_init(&event->hn_item);
 736                 spin_unlock(&o2hb_live_lock);
 737
 738                 mlog(ML_HEARTBEAT, "Node %s event for %d\n",
 739                      event->hn_event_type == O2HB_NODE_UP_CB ? "UP" : "DOWN",
 740                      event->hn_node_num);
 741
 742                 hbcall = hbcall_from_type(event->hn_event_type);
 743
 744                 /* We should *never* have gotten on to the list with a
 745                  * bad type... This isn't something that we should try
 746                  * to recover from. */
 747                 BUG_ON(IS_ERR(hbcall));
 748
 749                 o2hb_fire_callbacks(hbcall, event->hn_node, event->hn_node_num);
 750
 751                 spin_lock(&o2hb_live_lock);
 752         }
 753         spin_unlock(&o2hb_live_lock);
 754
 755         up_write(&o2hb_callback_sem);
 756 }
 757
 758 static void o2hb_queue_node_event(struct o2hb_node_event *event,
 759                                   enum o2hb_callback_type type,
 760                                   struct o2nm_node *node,
 761                                   int node_num)
 762 {
 763         assert_spin_locked(&o2hb_live_lock);
 764
 765         BUG_ON((!node) && (type != O2HB_NODE_DOWN_CB));
 766
 767         event->hn_event_type = type;
 768         event->hn_node = node;
 769         event->hn_node_num = node_num;
 770
 771         mlog(ML_HEARTBEAT, "Queue node %s event for node %d\n",
 772              type == O2HB_NODE_UP_CB ? "UP" : "DOWN", node_num);
 773
 774         list_add_tail(&event->hn_item, &o2hb_node_events);
 775 }
 776
 777 static void o2hb_shutdown_slot(struct o2hb_disk_slot *slot)
 778 {
 779         struct o2hb_node_event event =
 780                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 781         struct o2nm_node *node;
 782         int queued = 0;
 783
 784         node = o2nm_get_node_by_num(slot->ds_node_num);
 785         if (!node)
 786                 return;
 787
 788         spin_lock(&o2hb_live_lock);
 789         if (!list_empty(&slot->ds_live_item)) {
 790                 mlog(ML_HEARTBEAT, "Shutdown, node %d leaves region\n",
 791                      slot->ds_node_num);
 792
 793                 list_del_init(&slot->ds_live_item);
 794
 795                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 796                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 797
 798                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB, node,
 799                                               slot->ds_node_num);
 800                         queued = 1;
 801                 }
 802         }
 803         spin_unlock(&o2hb_live_lock);
 804
 805         if (queued)
 806                 o2hb_run_event_list(&event);
 807
 808         o2nm_node_put(node);
 809 }
 810
 811 static void o2hb_set_quorum_device(struct o2hb_region *reg)
 812 {
 813         if (!o2hb_global_heartbeat_active())
 814                 return;
 815
 816         /* Prevent race with o2hb_heartbeat_group_drop_item() */
 817         if (kthread_should_stop())
 818                 return;
 819
 820         /* Tag region as quorum only after thread reaches steady state */
 821         if (atomic_read(&reg->hr_steady_iterations) != 0)
 822                 return;
 823
 824         spin_lock(&o2hb_live_lock);
 825
 826         if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 827                 goto unlock;
 828
 829         /*
 830          * A region can be added to the quorum only when it sees all
 831          * live nodes heartbeat on it. In other words, the region has been
 832          * added to all nodes.
 833          */
 834         if (memcmp(reg->hr_live_node_bitmap, o2hb_live_node_bitmap,
 835                    sizeof(o2hb_live_node_bitmap)))
 836                 goto unlock;
 837
 838         printk(KERN_NOTICE "o2hb: Region %s (%s) is now a quorum device\n",
 839                config_item_name(&reg->hr_item), reg->hr_dev_name);
 840
 841         set_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
 842
 843         /*
 844          * If global heartbeat active, unpin all regions if the
 845          * region count > CUT_OFF
 846          */
 847         if (bitmap_weight(o2hb_quorum_region_bitmap,
 848                            O2NM_MAX_REGIONS) > O2HB_PIN_CUT_OFF)
 849                 o2hb_region_unpin(NULL);
 850 unlock:
 851         spin_unlock(&o2hb_live_lock);
 852 }
 853
 854 static int o2hb_check_slot(struct o2hb_region *reg,
 855                            struct o2hb_disk_slot *slot)
 856 {
 857         int changed = 0, gen_changed = 0;
 858         struct o2hb_node_event event =
 859                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 860         struct o2nm_node *node;
 861         struct o2hb_disk_heartbeat_block *hb_block = reg->hr_tmp_block;
 862         u64 cputime;
 863         unsigned int dead_ms = o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS;
 864         unsigned int slot_dead_ms;
 865         int tmp;
 866         int queued = 0;
 867
 868         memcpy(hb_block, slot->ds_raw_block, reg->hr_block_bytes);
 869
 870         /*
 871          * If a node is no longer configured but is still in the livemap, we
 872          * may need to clear that bit from the livemap.
 873          */
 874         node = o2nm_get_node_by_num(slot->ds_node_num);
 875         if (!node) {
 876                 spin_lock(&o2hb_live_lock);
 877                 tmp = test_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 878                 spin_unlock(&o2hb_live_lock);
 879                 if (!tmp)
 880                         return 0;
 881         }
 882
 883         if (!o2hb_verify_crc(reg, hb_block)) {
 884                 /* all paths from here will drop o2hb_live_lock for
 885                  * us. */
 886                 spin_lock(&o2hb_live_lock);
 887
 888                 /* Don't print an error on the console in this case -
 889                  * a freshly formatted heartbeat area will not have a
 890                  * crc set on it. */
 891                 if (list_empty(&slot->ds_live_item))
 892                         goto out;
 893
 894                 /* The node is live but pushed out a bad crc. We
 895                  * consider it a transient miss but don't populate any
 896                  * other values as they may be junk. */
 897                 mlog(ML_ERROR, "Node %d has written a bad crc to %s\n",
 898                      slot->ds_node_num, reg->hr_dev_name);
 899                 o2hb_dump_slot(hb_block);
 900
 901                 slot->ds_equal_samples++;
 902                 goto fire_callbacks;
 903         }
 904
 905         /* we don't care if these wrap.. the state transitions below
 906          * clear at the right places */
 907         cputime = le64_to_cpu(hb_block->hb_seq);
 908         if (slot->ds_last_time != cputime)
 909                 slot->ds_changed_samples++;
 910         else
 911                 slot->ds_equal_samples++;
 912         slot->ds_last_time = cputime;
 913
 914         /* The node changed heartbeat generations. We assume this to
 915          * mean it dropped off but came back before we timed out. We
 916          * want to consider it down for the time being but don't want
 917          * to lose any changed_samples state we might build up to
 918          * considering it live again. */
 919         if (slot->ds_last_generation != le64_to_cpu(hb_block->hb_generation)) {
 920                 gen_changed = 1;
 921                 slot->ds_equal_samples = 0;
 922                 mlog(ML_HEARTBEAT, "Node %d changed generation (0x%llx "
 923                      "to 0x%llx)\n", slot->ds_node_num,
 924                      (long long)slot->ds_last_generation,
 925                      (long long)le64_to_cpu(hb_block->hb_generation));
 926         }
 927
 928         slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
 929
 930         mlog(ML_HEARTBEAT, "Slot %d gen 0x%llx cksum 0x%x "
 931              "seq %llu last %llu changed %u equal %u\n",
 932              slot->ds_node_num, (long long)slot->ds_last_generation,
 933              le32_to_cpu(hb_block->hb_cksum),
 934              (unsigned long long)le64_to_cpu(hb_block->hb_seq),
 935              (unsigned long long)slot->ds_last_time, slot->ds_changed_samples,
 936              slot->ds_equal_samples);
 937
 938         spin_lock(&o2hb_live_lock);
 939
 940 fire_callbacks:
 941         /* dead nodes only come to life after some number of
 942          * changes at any time during their dead time */
 943         if (list_empty(&slot->ds_live_item) &&
 944             slot->ds_changed_samples >= O2HB_LIVE_THRESHOLD) {
 945                 mlog(ML_HEARTBEAT, "Node %d (id 0x%llx) joined my region\n",
 946                      slot->ds_node_num, (long long)slot->ds_last_generation);
 947
 948                 set_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 949
 950                 /* first on the list generates a callback */
 951                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 952                         mlog(ML_HEARTBEAT, "o2hb: Add node %d to live nodes "
 953                              "bitmap\n", slot->ds_node_num);
 954                         set_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 955
 956                         o2hb_queue_node_event(&event, O2HB_NODE_UP_CB, node,
 957                                               slot->ds_node_num);
 958
 959                         changed = 1;
 960                         queued = 1;
 961                 }
 962
 963                 list_add_tail(&slot->ds_live_item,
 964                               &o2hb_live_slots[slot->ds_node_num]);
 965
 966                 slot->ds_equal_samples = 0;
 967
 968                 /* We want to be sure that all nodes agree on the
 969                  * number of milliseconds before a node will be
 970                  * considered dead. The self-fencing timeout is
 971                  * computed from this value, and a discrepancy might
 972                  * result in heartbeat calling a node dead when it
 973                  * hasn't self-fenced yet. */
 974                 slot_dead_ms = le32_to_cpu(hb_block->hb_dead_ms);
 975                 if (slot_dead_ms && slot_dead_ms != dead_ms) {
 976                         /* TODO: Perhaps we can fail the region here. */
 977                         mlog(ML_ERROR, "Node %d on device %s has a dead count "
 978                              "of %u ms, but our count is %u ms.\n"
 979                              "Please double check your configuration values "
 980                              "for 'O2CB_HEARTBEAT_THRESHOLD'\n",
 981                              slot->ds_node_num, reg->hr_dev_name, slot_dead_ms,
 982                              dead_ms);
 983                 }
 984                 goto out;
 985         }
 986
 987         /* if the list is dead, we're done.. */
 988         if (list_empty(&slot->ds_live_item))
 989                 goto out;
 990
 991         /* live nodes only go dead after enough consequtive missed
 992          * samples..  reset the missed counter whenever we see
 993          * activity */
 994         if (slot->ds_equal_samples >= o2hb_dead_threshold || gen_changed) {
 995                 mlog(ML_HEARTBEAT, "Node %d left my region\n",
 996                      slot->ds_node_num);
 997
 998                 clear_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 999
1000                 /* last off the live_slot generates a callback */
1001                 list_del_init(&slot->ds_live_item);
1002                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
1003                         mlog(ML_HEARTBEAT, "o2hb: Remove node %d from live "
1004                              "nodes bitmap\n", slot->ds_node_num);
1005                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
1006
1007                         /* node can be null */
1008                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB,
1009                                               node, slot->ds_node_num);
1010
1011                         changed = 1;
1012                         queued = 1;
1013                 }
1014
1015                 /* We don't clear this because the node is still
1016                  * actually writing new blocks. */
1017                 if (!gen_changed)
1018                         slot->ds_changed_samples = 0;
1019                 goto out;
1020         }
1021         if (slot->ds_changed_samples) {
1022                 slot->ds_changed_samples = 0;
1023                 slot->ds_equal_samples = 0;
1024         }
1025 out:
1026         spin_unlock(&o2hb_live_lock);
1027
1028         if (queued)
1029                 o2hb_run_event_list(&event);
1030
1031         if (node)
1032                 o2nm_node_put(node);
1033         return changed;
1034 }
1035
1036 static int o2hb_highest_node(unsigned long *nodes, int numbits)
1037 {
1038         return find_last_bit(nodes, numbits);
1039 }
1040
1041 static int o2hb_do_disk_heartbeat(struct o2hb_region *reg)
1042 {
1043         int i, ret, highest_node;
1044         int membership_change = 0, own_slot_ok = 0;
1045         unsigned long configured_nodes[BITS_TO_LONGS(O2NM_MAX_NODES)];
1046         unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
1047         struct o2hb_bio_wait_ctxt write_wc;
1048
1049         ret = o2nm_configured_node_map(configured_nodes,
1050                                        sizeof(configured_nodes));
1051         if (ret) {
1052                 mlog_errno(ret);
1053                 goto bail;
1054         }
1055
1056         /*
1057          * If a node is not configured but is in the livemap, we still need
1058          * to read the slot so as to be able to remove it from the livemap.
1059          */
1060         o2hb_fill_node_map(live_node_bitmap, sizeof(live_node_bitmap));
1061         i = -1;
1062         while ((i = find_next_bit(live_node_bitmap,
1063                                   O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
1064                 set_bit(i, configured_nodes);
1065         }
1066
1067         highest_node = o2hb_highest_node(configured_nodes, O2NM_MAX_NODES);
1068         if (highest_node >= O2NM_MAX_NODES) {
1069                 mlog(ML_NOTICE, "o2hb: No configured nodes found!\n");
1070                 ret = -EINVAL;
1071                 goto bail;
1072         }
1073
1074         /* No sense in reading the slots of nodes that don't exist
1075          * yet. Of course, if the node definitions have holes in them
1076          * then we're reading an empty slot anyway... Consider this
1077          * best-effort. */
1078         ret = o2hb_read_slots(reg, highest_node + 1);
1079         if (ret < 0) {
1080                 mlog_errno(ret);
1081                 goto bail;
1082         }
1083
1084         /* With an up to date view of the slots, we can check that no
1085          * other node has been improperly configured to heartbeat in
1086          * our slot. */
1087         own_slot_ok = o2hb_check_own_slot(reg);
1088
1089         /* fill in the proper info for our next heartbeat */
1090         o2hb_prepare_block(reg, reg->hr_generation);
1091
1092         ret = o2hb_issue_node_write(reg, &write_wc);
1093         if (ret < 0) {
1094                 mlog_errno(ret);
1095                 goto bail;
1096         }
1097
1098         i = -1;
1099         while((i = find_next_bit(configured_nodes,
1100                                  O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
1101                 membership_change |= o2hb_check_slot(reg, &reg->hr_slots[i]);
1102         }
1103
1104         /*
1105          * We have to be sure we've advertised ourselves on disk
1106          * before we can go to steady state.  This ensures that
1107          * people we find in our steady state have seen us.
1108          */
1109         o2hb_wait_on_io(reg, &write_wc);
1110         if (write_wc.wc_error) {
1111                 /* Do not re-arm the write timeout on I/O error - we
1112                  * can't be sure that the new block ever made it to
1113                  * disk */
1114                 mlog(ML_ERROR, "Write error %d on device \"%s\"\n",
1115                      write_wc.wc_error, reg->hr_dev_name);
1116                 ret = write_wc.wc_error;
1117                 goto bail;
1118         }
1119
1120         /* Skip disarming the timeout if own slot has stale/bad data */
1121         if (own_slot_ok) {
1122                 o2hb_set_quorum_device(reg);
1123                 o2hb_arm_timeout(reg);
1124         }
1125
1126 bail:
1127         /* let the person who launched us know when things are steady */
1128         if (atomic_read(&reg->hr_steady_iterations) != 0) {
1129                 if (!ret && own_slot_ok && !membership_change) {
1130                         if (atomic_dec_and_test(&reg->hr_steady_iterations))
1131                                 wake_up(&o2hb_steady_queue);
1132                 }
1133         }
1134
1135         if (atomic_read(&reg->hr_steady_iterations) != 0) {
1136                 if (atomic_dec_and_test(&reg->hr_unsteady_iterations)) {
1137                         printk(KERN_NOTICE "o2hb: Unable to stabilize "
1138                                "heartbeart on region %s (%s)\n",
1139                                config_item_name(&reg->hr_item),
1140                                reg->hr_dev_name);
1141                         atomic_set(&reg->hr_steady_iterations, 0);
1142                         reg->hr_aborted_start = 1;
1143                         wake_up(&o2hb_steady_queue);
1144                         ret = -EIO;
1145                 }
1146         }
1147
1148         return ret;
1149 }
1150
1151 /*
1152  * we ride the region ref that the region dir holds.  before the region
1153  * dir is removed and drops it ref it will wait to tear down this
1154  * thread.
1155  */
1156 static int o2hb_thread(void *data)
1157 {
1158         int i, ret;
1159         struct o2hb_region *reg = data;
1160         struct o2hb_bio_wait_ctxt write_wc;
1161         ktime_t before_hb, after_hb;
1162         unsigned int elapsed_msec;
1163
1164         mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n");
1165
1166         set_user_nice(current, MIN_NICE);
1167
1168         /* Pin node */
1169         ret = o2nm_depend_this_node();
1170         if (ret) {
1171                 mlog(ML_ERROR, "Node has been deleted, ret = %d\n", ret);
1172                 reg->hr_node_deleted = 1;
1173                 wake_up(&o2hb_steady_queue);
1174                 return 0;
1175         }
1176
1177         while (!kthread_should_stop() &&
1178                !reg->hr_unclean_stop && !reg->hr_aborted_start) {
1179                 /* We track the time spent inside
1180                  * o2hb_do_disk_heartbeat so that we avoid more than
1181                  * hr_timeout_ms between disk writes. On busy systems
1182                  * this should result in a heartbeat which is less
1183                  * likely to time itself out. */
1184                 before_hb = ktime_get_real();
1185
1186                 ret = o2hb_do_disk_heartbeat(reg);
1187
1188                 after_hb = ktime_get_real();
1189
1190                 elapsed_msec = (unsigned int)
1191                                 ktime_ms_delta(after_hb, before_hb);
1192
1193                 mlog(ML_HEARTBEAT,
1194                      "start = %lld, end = %lld, msec = %u, ret = %d\n",
1195                      before_hb.tv64, after_hb.tv64, elapsed_msec, ret);
1196
1197                 if (!kthread_should_stop() &&
1198                     elapsed_msec < reg->hr_timeout_ms) {
1199                         /* the kthread api has blocked signals for us so no
1200                          * need to record the return value. */
1201                         msleep_interruptible(reg->hr_timeout_ms - elapsed_msec);
1202                 }
1203         }
1204
1205         o2hb_disarm_timeout(reg);
1206
1207         /* unclean stop is only used in very bad situation */
1208         for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
1209                 o2hb_shutdown_slot(&reg->hr_slots[i]);
1210
1211         /* Explicit down notification - avoid forcing the other nodes
1212          * to timeout on this region when we could just as easily
1213          * write a clear generation - thus indicating to them that
1214          * this node has left this region.
1215          */
1216         if (!reg->hr_unclean_stop && !reg->hr_aborted_start) {
1217                 o2hb_prepare_block(reg, 0);
1218                 ret = o2hb_issue_node_write(reg, &write_wc);
1219                 if (ret == 0)
1220                         o2hb_wait_on_io(reg, &write_wc);
1221                 else
1222                         mlog_errno(ret);
1223         }
1224
1225         /* Unpin node */
1226         o2nm_undepend_this_node();
1227
1228         mlog(ML_HEARTBEAT|ML_KTHREAD, "o2hb thread exiting\n");
1229
1230         return 0;
1231 }
1232
1233 #ifdef CONFIG_DEBUG_FS
1234 static int o2hb_debug_open(struct inode *inode, struct file *file)
1235 {
1236         struct o2hb_debug_buf *db = inode->i_private;
1237         struct o2hb_region *reg;
1238         unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1239         unsigned long lts;
1240         char *buf = NULL;
1241         int i = -1;
1242         int out = 0;
1243
1244         /* max_nodes should be the largest bitmap we pass here */
1245         BUG_ON(sizeof(map) < db->db_size);
1246
1247         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1248         if (!buf)
1249                 goto bail;
1250
1251         switch (db->db_type) {
1252         case O2HB_DB_TYPE_LIVENODES:
1253         case O2HB_DB_TYPE_LIVEREGIONS:
1254         case O2HB_DB_TYPE_QUORUMREGIONS:
1255         case O2HB_DB_TYPE_FAILEDREGIONS:
1256                 spin_lock(&o2hb_live_lock);
1257                 memcpy(map, db->db_data, db->db_size);
1258                 spin_unlock(&o2hb_live_lock);
1259                 break;
1260
1261         case O2HB_DB_TYPE_REGION_LIVENODES:
1262                 spin_lock(&o2hb_live_lock);
1263                 reg = (struct o2hb_region *)db->db_data;
1264                 memcpy(map, reg->hr_live_node_bitmap, db->db_size);
1265                 spin_unlock(&o2hb_live_lock);
1266                 break;
1267
1268         case O2HB_DB_TYPE_REGION_NUMBER:
1269                 reg = (struct o2hb_region *)db->db_data;
1270                 out += snprintf(buf + out, PAGE_SIZE - out, "%d\n",
1271                                 reg->hr_region_num);
1272                 goto done;
1273
1274         case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
1275                 reg = (struct o2hb_region *)db->db_data;
1276                 lts = reg->hr_last_timeout_start;
1277                 /* If 0, it has never been set before */
1278                 if (lts)
1279                         lts = jiffies_to_msecs(jiffies - lts);
1280                 out += snprintf(buf + out, PAGE_SIZE - out, "%lu\n", lts);
1281                 goto done;
1282
1283         case O2HB_DB_TYPE_REGION_PINNED:
1284                 reg = (struct o2hb_region *)db->db_data;
1285                 out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
1286                                 !!reg->hr_item_pinned);
1287                 goto done;
1288
1289         default:
1290                 goto done;
1291         }
1292
1293         while ((i = find_next_bit(map, db->db_len, i + 1)) < db->db_len)
1294                 out += snprintf(buf + out, PAGE_SIZE - out, "%d ", i);
1295         out += snprintf(buf + out, PAGE_SIZE - out, "\n");
1296
1297 done:
1298         i_size_write(inode, out);
1299
1300         file->private_data = buf;
1301
1302         return 0;
1303 bail:
1304         return -ENOMEM;
1305 }
1306
1307 static int o2hb_debug_release(struct inode *inode, struct file *file)
1308 {
1309         kfree(file->private_data);
1310         return 0;
1311 }
1312
1313 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1314                                  size_t nbytes, loff_t *ppos)
1315 {
1316         return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
1317                                        i_size_read(file->f_mapping->host));
1318 }
1319 #else
1320 static int o2hb_debug_open(struct inode *inode, struct file *file)
1321 {
1322         return 0;
1323 }
1324 static int o2hb_debug_release(struct inode *inode, struct file *file)
1325 {
1326         return 0;
1327 }
1328 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1329                                size_t nbytes, loff_t *ppos)
1330 {
1331         return 0;
1332 }
1333 #endif  /* CONFIG_DEBUG_FS */
1334
1335 static const struct file_operations o2hb_debug_fops = {
1336         .open =         o2hb_debug_open,
1337         .release =      o2hb_debug_release,
1338         .read =         o2hb_debug_read,
1339         .llseek =       generic_file_llseek,
1340 };
1341
1342 void o2hb_exit(void)
1343 {
1344         debugfs_remove(o2hb_debug_failedregions);
1345         debugfs_remove(o2hb_debug_quorumregions);
1346         debugfs_remove(o2hb_debug_liveregions);
1347         debugfs_remove(o2hb_debug_livenodes);
1348         debugfs_remove(o2hb_debug_dir);
1349         kfree(o2hb_db_livenodes);
1350         kfree(o2hb_db_liveregions);
1351         kfree(o2hb_db_quorumregions);
1352         kfree(o2hb_db_failedregions);
1353 }
1354
1355 static struct dentry *o2hb_debug_create(const char *name, struct dentry *dir,
1356                                         struct o2hb_debug_buf **db, int db_len,
1357                                         int type, int size, int len, void *data)
1358 {
1359         *db = kmalloc(db_len, GFP_KERNEL);
1360         if (!*db)
1361                 return NULL;
1362
1363         (*db)->db_type = type;
1364         (*db)->db_size = size;
1365         (*db)->db_len = len;
1366         (*db)->db_data = data;
1367
1368         return debugfs_create_file(name, S_IFREG|S_IRUSR, dir, *db,
1369                                    &o2hb_debug_fops);
1370 }
1371
1372 static int o2hb_debug_init(void)
1373 {
1374         int ret = -ENOMEM;
1375
1376         o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
1377         if (!o2hb_debug_dir) {
1378                 mlog_errno(ret);
1379                 goto bail;
1380         }
1381
1382         o2hb_debug_livenodes = o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1383                                                  o2hb_debug_dir,
1384                                                  &o2hb_db_livenodes,
1385                                                  sizeof(*o2hb_db_livenodes),
1386                                                  O2HB_DB_TYPE_LIVENODES,
1387                                                  sizeof(o2hb_live_node_bitmap),
1388                                                  O2NM_MAX_NODES,
1389                                                  o2hb_live_node_bitmap);
1390         if (!o2hb_debug_livenodes) {
1391                 mlog_errno(ret);
1392                 goto bail;
1393         }
1394
1395         o2hb_debug_liveregions = o2hb_debug_create(O2HB_DEBUG_LIVEREGIONS,
1396                                                    o2hb_debug_dir,
1397                                                    &o2hb_db_liveregions,
1398                                                    sizeof(*o2hb_db_liveregions),
1399                                                    O2HB_DB_TYPE_LIVEREGIONS,
1400                                                    sizeof(o2hb_live_region_bitmap),
1401                                                    O2NM_MAX_REGIONS,
1402                                                    o2hb_live_region_bitmap);
1403         if (!o2hb_debug_liveregions) {
1404                 mlog_errno(ret);
1405                 goto bail;
1406         }
1407
1408         o2hb_debug_quorumregions =
1409                         o2hb_debug_create(O2HB_DEBUG_QUORUMREGIONS,
1410                                           o2hb_debug_dir,
1411                                           &o2hb_db_quorumregions,
1412                                           sizeof(*o2hb_db_quorumregions),
1413                                           O2HB_DB_TYPE_QUORUMREGIONS,
1414                                           sizeof(o2hb_quorum_region_bitmap),
1415                                           O2NM_MAX_REGIONS,
1416                                           o2hb_quorum_region_bitmap);
1417         if (!o2hb_debug_quorumregions) {
1418                 mlog_errno(ret);
1419                 goto bail;
1420         }
1421
1422         o2hb_debug_failedregions =
1423                         o2hb_debug_create(O2HB_DEBUG_FAILEDREGIONS,
1424                                           o2hb_debug_dir,
1425                                           &o2hb_db_failedregions,
1426                                           sizeof(*o2hb_db_failedregions),
1427                                           O2HB_DB_TYPE_FAILEDREGIONS,
1428                                           sizeof(o2hb_failed_region_bitmap),
1429                                           O2NM_MAX_REGIONS,
1430                                           o2hb_failed_region_bitmap);
1431         if (!o2hb_debug_failedregions) {
1432                 mlog_errno(ret);
1433                 goto bail;
1434         }
1435
1436         ret = 0;
1437 bail:
1438         if (ret)
1439                 o2hb_exit();
1440
1441         return ret;
1442 }
1443
1444 int o2hb_init(void)
1445 {
1446         int i;
1447
1448         for (i = 0; i < ARRAY_SIZE(o2hb_callbacks); i++)
1449                 INIT_LIST_HEAD(&o2hb_callbacks[i].list);
1450
1451         for (i = 0; i < ARRAY_SIZE(o2hb_live_slots); i++)
1452                 INIT_LIST_HEAD(&o2hb_live_slots[i]);
1453
1454         INIT_LIST_HEAD(&o2hb_node_events);
1455
1456         memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
1457         memset(o2hb_region_bitmap, 0, sizeof(o2hb_region_bitmap));
1458         memset(o2hb_live_region_bitmap, 0, sizeof(o2hb_live_region_bitmap));
1459         memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
1460         memset(o2hb_failed_region_bitmap, 0, sizeof(o2hb_failed_region_bitmap));
1461
1462         o2hb_dependent_users = 0;
1463
1464         return o2hb_debug_init();
1465 }
1466
1467 /* if we're already in a callback then we're already serialized by the sem */
1468 static void o2hb_fill_node_map_from_callback(unsigned long *map,
1469                                              unsigned bytes)
1470 {
1471         BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1472
1473         memcpy(map, &o2hb_live_node_bitmap, bytes);
1474 }
1475
1476 /*
1477  * get a map of all nodes that are heartbeating in any regions
1478  */
1479 void o2hb_fill_node_map(unsigned long *map, unsigned bytes)
1480 {
1481         /* callers want to serialize this map and callbacks so that they
1482          * can trust that they don't miss nodes coming to the party */
1483         down_read(&o2hb_callback_sem);
1484         spin_lock(&o2hb_live_lock);
1485         o2hb_fill_node_map_from_callback(map, bytes);
1486         spin_unlock(&o2hb_live_lock);
1487         up_read(&o2hb_callback_sem);
1488 }
1489 EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
1490
1491 /*
1492  * heartbeat configfs bits.  The heartbeat set is a default set under
1493  * the cluster set in nodemanager.c.
1494  */
1495
1496 static struct o2hb_region *to_o2hb_region(struct config_item *item)
1497 {
1498         return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
1499 }
1500
1501 /* drop_item only drops its ref after killing the thread, nothing should
1502  * be using the region anymore.  this has to clean up any state that
1503  * attributes might have built up. */
1504 static void o2hb_region_release(struct config_item *item)
1505 {
1506         int i;
1507         struct page *page;
1508         struct o2hb_region *reg = to_o2hb_region(item);
1509
1510         mlog(ML_HEARTBEAT, "hb region release (%s)\n", reg->hr_dev_name);
1511
1512         kfree(reg->hr_tmp_block);
1513
1514         if (reg->hr_slot_data) {
1515                 for (i = 0; i < reg->hr_num_pages; i++) {
1516                         page = reg->hr_slot_data[i];
1517                         if (page)
1518                                 __free_page(page);
1519                 }
1520                 kfree(reg->hr_slot_data);
1521         }
1522
1523         if (reg->hr_bdev)
1524                 blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1525
1526         kfree(reg->hr_slots);
1527
1528         debugfs_remove(reg->hr_debug_livenodes);
1529         debugfs_remove(reg->hr_debug_regnum);
1530         debugfs_remove(reg->hr_debug_elapsed_time);
1531         debugfs_remove(reg->hr_debug_pinned);
1532         debugfs_remove(reg->hr_debug_dir);
1533         kfree(reg->hr_db_livenodes);
1534         kfree(reg->hr_db_regnum);
1535         kfree(reg->hr_db_elapsed_time);
1536         kfree(reg->hr_db_pinned);
1537
1538         spin_lock(&o2hb_live_lock);
1539         list_del(&reg->hr_all_item);
1540         spin_unlock(&o2hb_live_lock);
1541
1542         o2net_unregister_handler_list(&reg->hr_handler_list);
1543         kfree(reg);
1544 }
1545
1546 static int o2hb_read_block_input(struct o2hb_region *reg,
1547                                  const char *page,
1548                                  unsigned long *ret_bytes,
1549                                  unsigned int *ret_bits)
1550 {
1551         unsigned long bytes;
1552         char *p = (char *)page;
1553
1554         bytes = simple_strtoul(p, &p, 0);
1555         if (!p || (*p && (*p != '\n')))
1556                 return -EINVAL;
1557
1558         /* Heartbeat and fs min / max block sizes are the same. */
1559         if (bytes > 4096 || bytes < 512)
1560                 return -ERANGE;
1561         if (hweight16(bytes) != 1)
1562                 return -EINVAL;
1563
1564         if (ret_bytes)
1565                 *ret_bytes = bytes;
1566         if (ret_bits)
1567                 *ret_bits = ffs(bytes) - 1;
1568
1569         return 0;
1570 }
1571
1572 static ssize_t o2hb_region_block_bytes_show(struct config_item *item,
1573                                             char *page)
1574 {
1575         return sprintf(page, "%u\n", to_o2hb_region(item)->hr_block_bytes);
1576 }
1577
1578 static ssize_t o2hb_region_block_bytes_store(struct config_item *item,
1579                                              const char *page,
1580                                              size_t count)
1581 {
1582         struct o2hb_region *reg = to_o2hb_region(item);
1583         int status;
1584         unsigned long block_bytes;
1585         unsigned int block_bits;
1586
1587         if (reg->hr_bdev)
1588                 return -EINVAL;
1589
1590         status = o2hb_read_block_input(reg, page, &block_bytes,
1591                                        &block_bits);
1592         if (status)
1593                 return status;
1594
1595         reg->hr_block_bytes = (unsigned int)block_bytes;
1596         reg->hr_block_bits = block_bits;
1597
1598         return count;
1599 }
1600
1601 static ssize_t o2hb_region_start_block_show(struct config_item *item,
1602                                             char *page)
1603 {
1604         return sprintf(page, "%llu\n", to_o2hb_region(item)->hr_start_block);
1605 }
1606
1607 static ssize_t o2hb_region_start_block_store(struct config_item *item,
1608                                              const char *page,
1609                                              size_t count)
1610 {
1611         struct o2hb_region *reg = to_o2hb_region(item);
1612         unsigned long long tmp;
1613         char *p = (char *)page;
1614
1615         if (reg->hr_bdev)
1616                 return -EINVAL;
1617
1618         tmp = simple_strtoull(p, &p, 0);
1619         if (!p || (*p && (*p != '\n')))
1620                 return -EINVAL;
1621
1622         reg->hr_start_block = tmp;
1623
1624         return count;
1625 }
1626
1627 static ssize_t o2hb_region_blocks_show(struct config_item *item, char *page)
1628 {
1629         return sprintf(page, "%d\n", to_o2hb_region(item)->hr_blocks);
1630 }
1631
1632 static ssize_t o2hb_region_blocks_store(struct config_item *item,
1633                                         const char *page,
1634                                         size_t count)
1635 {
1636         struct o2hb_region *reg = to_o2hb_region(item);
1637         unsigned long tmp;
1638         char *p = (char *)page;
1639
1640         if (reg->hr_bdev)
1641                 return -EINVAL;
1642
1643         tmp = simple_strtoul(p, &p, 0);
1644         if (!p || (*p && (*p != '\n')))
1645                 return -EINVAL;
1646
1647         if (tmp > O2NM_MAX_NODES || tmp == 0)
1648                 return -ERANGE;
1649
1650         reg->hr_blocks = (unsigned int)tmp;
1651
1652         return count;
1653 }
1654
1655 static ssize_t o2hb_region_dev_show(struct config_item *item, char *page)
1656 {
1657         unsigned int ret = 0;
1658
1659         if (to_o2hb_region(item)->hr_bdev)
1660                 ret = sprintf(page, "%s\n", to_o2hb_region(item)->hr_dev_name);
1661
1662         return ret;
1663 }
1664
1665 static void o2hb_init_region_params(struct o2hb_region *reg)
1666 {
1667         reg->hr_slots_per_page = PAGE_SIZE >> reg->hr_block_bits;
1668         reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
1669
1670         mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
1671              reg->hr_start_block, reg->hr_blocks);
1672         mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
1673              reg->hr_block_bytes, reg->hr_block_bits);
1674         mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
1675         mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
1676 }
1677
1678 static int o2hb_map_slot_data(struct o2hb_region *reg)
1679 {
1680         int i, j;
1681         unsigned int last_slot;
1682         unsigned int spp = reg->hr_slots_per_page;
1683         struct page *page;
1684         char *raw;
1685         struct o2hb_disk_slot *slot;
1686
1687         reg->hr_tmp_block = kmalloc(reg->hr_block_bytes, GFP_KERNEL);
1688         if (reg->hr_tmp_block == NULL)
1689                 return -ENOMEM;
1690
1691         reg->hr_slots = kcalloc(reg->hr_blocks,
1692                                 sizeof(struct o2hb_disk_slot), GFP_KERNEL);
1693         if (reg->hr_slots == NULL)
1694                 return -ENOMEM;
1695
1696         for(i = 0; i < reg->hr_blocks; i++) {
1697                 slot = &reg->hr_slots[i];
1698                 slot->ds_node_num = i;
1699                 INIT_LIST_HEAD(&slot->ds_live_item);
1700                 slot->ds_raw_block = NULL;
1701         }
1702
1703         reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
1704         mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
1705                            "at %u blocks per page\n",
1706              reg->hr_num_pages, reg->hr_blocks, spp);
1707
1708         reg->hr_slot_data = kcalloc(reg->hr_num_pages, sizeof(struct page *),
1709                                     GFP_KERNEL);
1710         if (!reg->hr_slot_data)
1711                 return -ENOMEM;
1712
1713         for(i = 0; i < reg->hr_num_pages; i++) {
1714                 page = alloc_page(GFP_KERNEL);
1715                 if (!page)
1716                         return -ENOMEM;
1717
1718                 reg->hr_slot_data[i] = page;
1719
1720                 last_slot = i * spp;
1721                 raw = page_address(page);
1722                 for (j = 0;
1723                      (j < spp) && ((j + last_slot) < reg->hr_blocks);
1724                      j++) {
1725                         BUG_ON((j + last_slot) >= reg->hr_blocks);
1726
1727                         slot = &reg->hr_slots[j + last_slot];
1728                         slot->ds_raw_block =
1729                                 (struct o2hb_disk_heartbeat_block *) raw;
1730
1731                         raw += reg->hr_block_bytes;
1732                 }
1733         }
1734
1735         return 0;
1736 }
1737
1738 /* Read in all the slots available and populate the tracking
1739  * structures so that we can start with a baseline idea of what's
1740  * there. */
1741 static int o2hb_populate_slot_data(struct o2hb_region *reg)
1742 {
1743         int ret, i;
1744         struct o2hb_disk_slot *slot;
1745         struct o2hb_disk_heartbeat_block *hb_block;
1746
1747         ret = o2hb_read_slots(reg, reg->hr_blocks);
1748         if (ret)
1749                 goto out;
1750
1751         /* We only want to get an idea of the values initially in each
1752          * slot, so we do no verification - o2hb_check_slot will
1753          * actually determine if each configured slot is valid and
1754          * whether any values have changed. */
1755         for(i = 0; i < reg->hr_blocks; i++) {
1756                 slot = &reg->hr_slots[i];
1757                 hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
1758
1759                 /* Only fill the values that o2hb_check_slot uses to
1760                  * determine changing slots */
1761                 slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
1762                 slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
1763         }
1764
1765 out:
1766         return ret;
1767 }
1768
1769 /* this is acting as commit; we set up all of hr_bdev and hr_task or nothing */
1770 static ssize_t o2hb_region_dev_store(struct config_item *item,
1771                                      const char *page,
1772                                      size_t count)
1773 {
1774         struct o2hb_region *reg = to_o2hb_region(item);
1775         struct task_struct *hb_task;
1776         long fd;
1777         int sectsize;
1778         char *p = (char *)page;
1779         struct fd f;
1780         struct inode *inode;
1781         ssize_t ret = -EINVAL;
1782         int live_threshold;
1783
1784         if (reg->hr_bdev)
1785                 goto out;
1786
1787         /* We can't heartbeat without having had our node number
1788          * configured yet. */
1789         if (o2nm_this_node() == O2NM_MAX_NODES)
1790                 goto out;
1791
1792         fd = simple_strtol(p, &p, 0);
1793         if (!p || (*p && (*p != '\n')))
1794                 goto out;
1795
1796         if (fd < 0 || fd >= INT_MAX)
1797                 goto out;
1798
1799         f = fdget(fd);
1800         if (f.file == NULL)
1801                 goto out;
1802
1803         if (reg->hr_blocks == 0 || reg->hr_start_block == 0 ||
1804             reg->hr_block_bytes == 0)
1805                 goto out2;
1806
1807         inode = igrab(f.file->f_mapping->host);
1808         if (inode == NULL)
1809                 goto out2;
1810
1811         if (!S_ISBLK(inode->i_mode))
1812                 goto out3;
1813
1814         reg->hr_bdev = I_BDEV(f.file->f_mapping->host);
1815         ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ, NULL);
1816         if (ret) {
1817                 reg->hr_bdev = NULL;
1818                 goto out3;
1819         }
1820         inode = NULL;
1821
1822         bdevname(reg->hr_bdev, reg->hr_dev_name);
1823
1824         sectsize = bdev_logical_block_size(reg->hr_bdev);
1825         if (sectsize != reg->hr_block_bytes) {
1826                 mlog(ML_ERROR,
1827                      "blocksize %u incorrect for device, expected %d",
1828                      reg->hr_block_bytes, sectsize);
1829                 ret = -EINVAL;
1830                 goto out3;
1831         }
1832
1833         o2hb_init_region_params(reg);
1834
1835         /* Generation of zero is invalid */
1836         do {
1837                 get_random_bytes(&reg->hr_generation,
1838                                  sizeof(reg->hr_generation));
1839         } while (reg->hr_generation == 0);
1840
1841         ret = o2hb_map_slot_data(reg);
1842         if (ret) {
1843                 mlog_errno(ret);
1844                 goto out3;
1845         }
1846
1847         ret = o2hb_populate_slot_data(reg);
1848         if (ret) {
1849                 mlog_errno(ret);
1850                 goto out3;
1851         }
1852
1853         INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
1854         INIT_DELAYED_WORK(&reg->hr_nego_timeout_work, o2hb_nego_timeout);
1855
1856         /*
1857          * A node is considered live after it has beat LIVE_THRESHOLD
1858          * times.  We're not steady until we've given them a chance
1859          * _after_ our first read.
1860          * The default threshold is bare minimum so as to limit the delay
1861          * during mounts. For global heartbeat, the threshold doubled for the
1862          * first region.
1863          */
1864         live_threshold = O2HB_LIVE_THRESHOLD;
1865         if (o2hb_global_heartbeat_active()) {
1866                 spin_lock(&o2hb_live_lock);
1867                 if (bitmap_weight(o2hb_region_bitmap, O2NM_MAX_REGIONS) == 1)
1868                         live_threshold <<= 1;
1869                 spin_unlock(&o2hb_live_lock);
1870         }
1871         ++live_threshold;
1872         atomic_set(&reg->hr_steady_iterations, live_threshold);
1873         /* unsteady_iterations is triple the steady_iterations */
1874         atomic_set(&reg->hr_unsteady_iterations, (live_threshold * 3));
1875
1876         hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
1877                               reg->hr_item.ci_name);
1878         if (IS_ERR(hb_task)) {
1879                 ret = PTR_ERR(hb_task);
1880                 mlog_errno(ret);
1881                 goto out3;
1882         }
1883
1884         spin_lock(&o2hb_live_lock);
1885         reg->hr_task = hb_task;
1886         spin_unlock(&o2hb_live_lock);
1887
1888         ret = wait_event_interruptible(o2hb_steady_queue,
1889                                 atomic_read(&reg->hr_steady_iterations) == 0 ||
1890                                 reg->hr_node_deleted);
1891         if (ret) {
1892                 atomic_set(&reg->hr_steady_iterations, 0);
1893                 reg->hr_aborted_start = 1;
1894         }
1895
1896         if (reg->hr_aborted_start) {
1897                 ret = -EIO;
1898                 goto out3;
1899         }
1900
1901         if (reg->hr_node_deleted) {
1902                 ret = -EINVAL;
1903                 goto out3;
1904         }
1905
1906         /* Ok, we were woken.  Make sure it wasn't by drop_item() */
1907         spin_lock(&o2hb_live_lock);
1908         hb_task = reg->hr_task;
1909         if (o2hb_global_heartbeat_active())
1910                 set_bit(reg->hr_region_num, o2hb_live_region_bitmap);
1911         spin_unlock(&o2hb_live_lock);
1912
1913         if (hb_task)
1914                 ret = count;
1915         else
1916                 ret = -EIO;
1917
1918         if (hb_task && o2hb_global_heartbeat_active())
1919                 printk(KERN_NOTICE "o2hb: Heartbeat started on region %s (%s)\n",
1920                        config_item_name(&reg->hr_item), reg->hr_dev_name);
1921
1922 out3:
1923         iput(inode);
1924 out2:
1925         fdput(f);
1926 out:
1927         if (ret < 0) {
1928                 if (reg->hr_bdev) {
1929                         blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1930                         reg->hr_bdev = NULL;
1931                 }
1932         }
1933         return ret;
1934 }
1935
1936 static ssize_t o2hb_region_pid_show(struct config_item *item, char *page)
1937 {
1938         struct o2hb_region *reg = to_o2hb_region(item);
1939         pid_t pid = 0;
1940
1941         spin_lock(&o2hb_live_lock);
1942         if (reg->hr_task)
1943                 pid = task_pid_nr(reg->hr_task);
1944         spin_unlock(&o2hb_live_lock);
1945
1946         if (!pid)
1947                 return 0;
1948
1949         return sprintf(page, "%u\n", pid);
1950 }
1951
1952 CONFIGFS_ATTR(o2hb_region_, block_bytes);
1953 CONFIGFS_ATTR(o2hb_region_, start_block);
1954 CONFIGFS_ATTR(o2hb_region_, blocks);
1955 CONFIGFS_ATTR(o2hb_region_, dev);
1956 CONFIGFS_ATTR_RO(o2hb_region_, pid);
1957
1958 static struct configfs_attribute *o2hb_region_attrs[] = {
1959         &o2hb_region_attr_block_bytes,
1960         &o2hb_region_attr_start_block,
1961         &o2hb_region_attr_blocks,
1962         &o2hb_region_attr_dev,
1963         &o2hb_region_attr_pid,
1964         NULL,
1965 };
1966
1967 static struct configfs_item_operations o2hb_region_item_ops = {
1968         .release                = o2hb_region_release,
1969 };
1970
1971 static struct config_item_type o2hb_region_type = {
1972         .ct_item_ops    = &o2hb_region_item_ops,
1973         .ct_attrs       = o2hb_region_attrs,
1974         .ct_owner       = THIS_MODULE,
1975 };
1976
1977 /* heartbeat set */
1978
1979 struct o2hb_heartbeat_group {
1980         struct config_group hs_group;
1981         /* some stuff? */
1982 };
1983
1984 static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
1985 {
1986         return group ?
1987                 container_of(group, struct o2hb_heartbeat_group, hs_group)
1988                 : NULL;
1989 }
1990
1991 static int o2hb_debug_region_init(struct o2hb_region *reg, struct dentry *dir)
1992 {
1993         int ret = -ENOMEM;
1994
1995         reg->hr_debug_dir =
1996                 debugfs_create_dir(config_item_name(&reg->hr_item), dir);
1997         if (!reg->hr_debug_dir) {
1998                 mlog_errno(ret);
1999                 goto bail;
2000         }
2001
2002         reg->hr_debug_livenodes =
2003                         o2hb_debug_create(O2HB_DEBUG_LIVENODES,
2004                                           reg->hr_debug_dir,
2005                                           &(reg->hr_db_livenodes),
2006                                           sizeof(*(reg->hr_db_livenodes)),
2007                                           O2HB_DB_TYPE_REGION_LIVENODES,
2008                                           sizeof(reg->hr_live_node_bitmap),
2009                                           O2NM_MAX_NODES, reg);
2010         if (!reg->hr_debug_livenodes) {
2011                 mlog_errno(ret);
2012                 goto bail;
2013         }
2014
2015         reg->hr_debug_regnum =
2016                         o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER,
2017                                           reg->hr_debug_dir,
2018                                           &(reg->hr_db_regnum),
2019                                           sizeof(*(reg->hr_db_regnum)),
2020                                           O2HB_DB_TYPE_REGION_NUMBER,
2021                                           0, O2NM_MAX_NODES, reg);
2022         if (!reg->hr_debug_regnum) {
2023                 mlog_errno(ret);
2024                 goto bail;
2025         }
2026
2027         reg->hr_debug_elapsed_time =
2028                         o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME,
2029                                           reg->hr_debug_dir,
2030                                           &(reg->hr_db_elapsed_time),
2031                                           sizeof(*(reg->hr_db_elapsed_time)),
2032                                           O2HB_DB_TYPE_REGION_ELAPSED_TIME,
2033                                           0, 0, reg);
2034         if (!reg->hr_debug_elapsed_time) {
2035                 mlog_errno(ret);
2036                 goto bail;
2037         }
2038
2039         reg->hr_debug_pinned =
2040                         o2hb_debug_create(O2HB_DEBUG_REGION_PINNED,
2041                                           reg->hr_debug_dir,
2042                                           &(reg->hr_db_pinned),
2043                                           sizeof(*(reg->hr_db_pinned)),
2044                                           O2HB_DB_TYPE_REGION_PINNED,
2045                                           0, 0, reg);
2046         if (!reg->hr_debug_pinned) {
2047                 mlog_errno(ret);
2048                 goto bail;
2049         }
2050
2051         ret = 0;
2052 bail:
2053         return ret;
2054 }
2055
2056 static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
2057                                                           const char *name)
2058 {
2059         struct o2hb_region *reg = NULL;
2060         int ret;
2061
2062         reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
2063         if (reg == NULL)
2064                 return ERR_PTR(-ENOMEM);
2065
2066         if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
2067                 ret = -ENAMETOOLONG;
2068                 goto free;
2069         }
2070
2071         spin_lock(&o2hb_live_lock);
2072         reg->hr_region_num = 0;
2073         if (o2hb_global_heartbeat_active()) {
2074                 reg->hr_region_num = find_first_zero_bit(o2hb_region_bitmap,
2075                                                          O2NM_MAX_REGIONS);
2076                 if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
2077                         spin_unlock(&o2hb_live_lock);
2078                         ret = -EFBIG;
2079                         goto free;
2080                 }
2081                 set_bit(reg->hr_region_num, o2hb_region_bitmap);
2082         }
2083         list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
2084         spin_unlock(&o2hb_live_lock);
2085
2086         config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
2087
2088         /* this is the same way to generate msg key as dlm, for local heartbeat,
2089          * name is also the same, so make initial crc value different to avoid
2090          * message key conflict.
2091          */
2092         reg->hr_key = crc32_le(reg->hr_region_num + O2NM_MAX_REGIONS,
2093                 name, strlen(name));
2094         INIT_LIST_HEAD(&reg->hr_handler_list);
2095         ret = o2net_register_handler(O2HB_NEGO_TIMEOUT_MSG, reg->hr_key,
2096                         sizeof(struct o2hb_nego_msg),
2097                         o2hb_nego_timeout_handler,
2098                         reg, NULL, &reg->hr_handler_list);
2099         if (ret)
2100                 goto free;
2101
2102         ret = o2hb_debug_region_init(reg, o2hb_debug_dir);
2103         if (ret) {
2104                 config_item_put(&reg->hr_item);
2105                 goto unregister_handler;
2106         }
2107
2108         return &reg->hr_item;
2109
2110 unregister_handler:
2111         o2net_unregister_handler_list(&reg->hr_handler_list);
2112 free:
2113         kfree(reg);
2114         return ERR_PTR(ret);
2115 }
2116
2117 static void o2hb_heartbeat_group_drop_item(struct config_group *group,
2118                                            struct config_item *item)
2119 {
2120         struct task_struct *hb_task;
2121         struct o2hb_region *reg = to_o2hb_region(item);
2122         int quorum_region = 0;
2123
2124         /* stop the thread when the user removes the region dir */
2125         spin_lock(&o2hb_live_lock);
2126         hb_task = reg->hr_task;
2127         reg->hr_task = NULL;
2128         reg->hr_item_dropped = 1;
2129         spin_unlock(&o2hb_live_lock);
2130
2131         if (hb_task)
2132                 kthread_stop(hb_task);
2133
2134         if (o2hb_global_heartbeat_active()) {
2135                 spin_lock(&o2hb_live_lock);
2136                 clear_bit(reg->hr_region_num, o2hb_region_bitmap);
2137                 clear_bit(reg->hr_region_num, o2hb_live_region_bitmap);
2138                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
2139                         quorum_region = 1;
2140                 clear_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
2141                 spin_unlock(&o2hb_live_lock);
2142                 printk(KERN_NOTICE "o2hb: Heartbeat %s on region %s (%s)\n",
2143                        ((atomic_read(&reg->hr_steady_iterations) == 0) ?
2144                         "stopped" : "start aborted"), config_item_name(item),
2145                        reg->hr_dev_name);
2146         }
2147
2148         /*
2149          * If we're racing a dev_write(), we need to wake them.  They will
2150          * check reg->hr_task
2151          */
2152         if (atomic_read(&reg->hr_steady_iterations) != 0) {
2153                 reg->hr_aborted_start = 1;
2154                 atomic_set(&reg->hr_steady_iterations, 0);
2155                 wake_up(&o2hb_steady_queue);
2156         }
2157
2158         config_item_put(item);
2159
2160         if (!o2hb_global_heartbeat_active() || !quorum_region)
2161                 return;
2162
2163         /*
2164          * If global heartbeat active and there are dependent users,
2165          * pin all regions if quorum region count <= CUT_OFF
2166          */
2167         spin_lock(&o2hb_live_lock);
2168
2169         if (!o2hb_dependent_users)
2170                 goto unlock;
2171
2172         if (bitmap_weight(o2hb_quorum_region_bitmap,
2173                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2174                 o2hb_region_pin(NULL);
2175
2176 unlock:
2177         spin_unlock(&o2hb_live_lock);
2178 }
2179
2180 static ssize_t o2hb_heartbeat_group_threshold_show(struct config_item *item,
2181                 char *page)
2182 {
2183         return sprintf(page, "%u\n", o2hb_dead_threshold);
2184 }
2185
2186 static ssize_t o2hb_heartbeat_group_threshold_store(struct config_item *item,
2187                 const char *page, size_t count)
2188 {
2189         unsigned long tmp;
2190         char *p = (char *)page;
2191
2192         tmp = simple_strtoul(p, &p, 10);
2193         if (!p || (*p && (*p != '\n')))
2194                 return -EINVAL;
2195
2196         /* this will validate ranges for us. */
2197         o2hb_dead_threshold_set((unsigned int) tmp);
2198
2199         return count;
2200 }
2201
2202 static ssize_t o2hb_heartbeat_group_mode_show(struct config_item *item,
2203                 char *page)
2204 {
2205         return sprintf(page, "%s\n",
2206                        o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
2207 }
2208
2209 static ssize_t o2hb_heartbeat_group_mode_store(struct config_item *item,
2210                 const char *page, size_t count)
2211 {
2212         unsigned int i;
2213         int ret;
2214         size_t len;
2215
2216         len = (page[count - 1] == '\n') ? count - 1 : count;
2217         if (!len)
2218                 return -EINVAL;
2219
2220         for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
2221                 if (strncasecmp(page, o2hb_heartbeat_mode_desc[i], len))
2222                         continue;
2223
2224                 ret = o2hb_global_heartbeat_mode_set(i);
2225                 if (!ret)
2226                         printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
2227                                o2hb_heartbeat_mode_desc[i]);
2228                 return count;
2229         }
2230
2231         return -EINVAL;
2232
2233 }
2234
2235 CONFIGFS_ATTR(o2hb_heartbeat_group_, threshold);
2236 CONFIGFS_ATTR(o2hb_heartbeat_group_, mode);
2237
2238 static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
2239         &o2hb_heartbeat_group_attr_threshold,
2240         &o2hb_heartbeat_group_attr_mode,
2241         NULL,
2242 };
2243
2244 static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
2245         .make_item      = o2hb_heartbeat_group_make_item,
2246         .drop_item      = o2hb_heartbeat_group_drop_item,
2247 };
2248
2249 static struct config_item_type o2hb_heartbeat_group_type = {
2250         .ct_group_ops   = &o2hb_heartbeat_group_group_ops,
2251         .ct_attrs       = o2hb_heartbeat_group_attrs,
2252         .ct_owner       = THIS_MODULE,
2253 };
2254
2255 /* this is just here to avoid touching group in heartbeat.h which the
2256  * entire damn world #includes */
2257 struct config_group *o2hb_alloc_hb_set(void)
2258 {
2259         struct o2hb_heartbeat_group *hs = NULL;
2260         struct config_group *ret = NULL;
2261
2262         hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
2263         if (hs == NULL)
2264                 goto out;
2265
2266         config_group_init_type_name(&hs->hs_group, "heartbeat",
2267                                     &o2hb_heartbeat_group_type);
2268
2269         ret = &hs->hs_group;
2270 out:
2271         if (ret == NULL)
2272                 kfree(hs);
2273         return ret;
2274 }
2275
2276 void o2hb_free_hb_set(struct config_group *group)
2277 {
2278         struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
2279         kfree(hs);
2280 }
2281
2282 /* hb callback registration and issuing */
2283
2284 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
2285 {
2286         if (type == O2HB_NUM_CB)
2287                 return ERR_PTR(-EINVAL);
2288
2289         return &o2hb_callbacks[type];
2290 }
2291
2292 void o2hb_setup_callback(struct o2hb_callback_func *hc,
2293                          enum o2hb_callback_type type,
2294                          o2hb_cb_func *func,
2295                          void *data,
2296                          int priority)
2297 {
2298         INIT_LIST_HEAD(&hc->hc_item);
2299         hc->hc_func = func;
2300         hc->hc_data = data;
2301         hc->hc_priority = priority;
2302         hc->hc_type = type;
2303         hc->hc_magic = O2HB_CB_MAGIC;
2304 }
2305 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
2306
2307 /*
2308  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2309  * In global heartbeat mode, region_uuid passed is NULL.
2310  *
2311  * In local, we only pin the matching region. In global we pin all the active
2312  * regions.
2313  */
2314 static int o2hb_region_pin(const char *region_uuid)
2315 {
2316         int ret = 0, found = 0;
2317         struct o2hb_region *reg;
2318         char *uuid;
2319
2320         assert_spin_locked(&o2hb_live_lock);
2321
2322         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2323                 if (reg->hr_item_dropped)
2324                         continue;
2325
2326                 uuid = config_item_name(&reg->hr_item);
2327
2328                 /* local heartbeat */
2329                 if (region_uuid) {
2330                         if (strcmp(region_uuid, uuid))
2331                                 continue;
2332                         found = 1;
2333                 }
2334
2335                 if (reg->hr_item_pinned || reg->hr_item_dropped)
2336                         goto skip_pin;
2337
2338                 /* Ignore ENOENT only for local hb (userdlm domain) */
2339                 ret = o2nm_depend_item(&reg->hr_item);
2340                 if (!ret) {
2341                         mlog(ML_CLUSTER, "Pin region %s\n", uuid);
2342                         reg->hr_item_pinned = 1;
2343                 } else {
2344                         if (ret == -ENOENT && found)
2345                                 ret = 0;
2346                         else {
2347                                 mlog(ML_ERROR, "Pin region %s fails with %d\n",
2348                                      uuid, ret);
2349                                 break;
2350                         }
2351                 }
2352 skip_pin:
2353                 if (found)
2354                         break;
2355         }
2356
2357         return ret;
2358 }
2359
2360 /*
2361  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2362  * In global heartbeat mode, region_uuid passed is NULL.
2363  *
2364  * In local, we only unpin the matching region. In global we unpin all the
2365  * active regions.
2366  */
2367 static void o2hb_region_unpin(const char *region_uuid)
2368 {
2369         struct o2hb_region *reg;
2370         char *uuid;
2371         int found = 0;
2372
2373         assert_spin_locked(&o2hb_live_lock);
2374
2375         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2376                 if (reg->hr_item_dropped)
2377                         continue;
2378
2379                 uuid = config_item_name(&reg->hr_item);
2380                 if (region_uuid) {
2381                         if (strcmp(region_uuid, uuid))
2382                                 continue;
2383                         found = 1;
2384                 }
2385
2386                 if (reg->hr_item_pinned) {
2387                         mlog(ML_CLUSTER, "Unpin region %s\n", uuid);
2388                         o2nm_undepend_item(&reg->hr_item);
2389                         reg->hr_item_pinned = 0;
2390                 }
2391                 if (found)
2392                         break;
2393         }
2394 }
2395
2396 static int o2hb_region_inc_user(const char *region_uuid)
2397 {
2398         int ret = 0;
2399
2400         spin_lock(&o2hb_live_lock);
2401
2402         /* local heartbeat */
2403         if (!o2hb_global_heartbeat_active()) {
2404             ret = o2hb_region_pin(region_uuid);
2405             goto unlock;
2406         }
2407
2408         /*
2409          * if global heartbeat active and this is the first dependent user,
2410          * pin all regions if quorum region count <= CUT_OFF
2411          */
2412         o2hb_dependent_users++;
2413         if (o2hb_dependent_users > 1)
2414                 goto unlock;
2415
2416         if (bitmap_weight(o2hb_quorum_region_bitmap,
2417                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2418                 ret = o2hb_region_pin(NULL);
2419
2420 unlock:
2421         spin_unlock(&o2hb_live_lock);
2422         return ret;
2423 }
2424
2425 void o2hb_region_dec_user(const char *region_uuid)
2426 {
2427         spin_lock(&o2hb_live_lock);
2428
2429         /* local heartbeat */
2430         if (!o2hb_global_heartbeat_active()) {
2431             o2hb_region_unpin(region_uuid);
2432             goto unlock;
2433         }
2434
2435         /*
2436          * if global heartbeat active and there are no dependent users,
2437          * unpin all quorum regions
2438          */
2439         o2hb_dependent_users--;
2440         if (!o2hb_dependent_users)
2441                 o2hb_region_unpin(NULL);
2442
2443 unlock:
2444         spin_unlock(&o2hb_live_lock);
2445 }
2446
2447 int o2hb_register_callback(const char *region_uuid,
2448                            struct o2hb_callback_func *hc)
2449 {
2450         struct o2hb_callback_func *f;
2451         struct o2hb_callback *hbcall;
2452         int ret;
2453
2454         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2455         BUG_ON(!list_empty(&hc->hc_item));
2456
2457         hbcall = hbcall_from_type(hc->hc_type);
2458         if (IS_ERR(hbcall)) {
2459                 ret = PTR_ERR(hbcall);
2460                 goto out;
2461         }
2462
2463         if (region_uuid) {
2464                 ret = o2hb_region_inc_user(region_uuid);
2465                 if (ret) {
2466                         mlog_errno(ret);
2467                         goto out;
2468                 }
2469         }
2470
2471         down_write(&o2hb_callback_sem);
2472
2473         list_for_each_entry(f, &hbcall->list, hc_item) {
2474                 if (hc->hc_priority < f->hc_priority) {
2475                         list_add_tail(&hc->hc_item, &f->hc_item);
2476                         break;
2477                 }
2478         }
2479         if (list_empty(&hc->hc_item))
2480                 list_add_tail(&hc->hc_item, &hbcall->list);
2481
2482         up_write(&o2hb_callback_sem);
2483         ret = 0;
2484 out:
2485         mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
2486              ret, __builtin_return_address(0), hc);
2487         return ret;
2488 }
2489 EXPORT_SYMBOL_GPL(o2hb_register_callback);
2490
2491 void o2hb_unregister_callback(const char *region_uuid,
2492                               struct o2hb_callback_func *hc)
2493 {
2494         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2495
2496         mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
2497              __builtin_return_address(0), hc);
2498
2499         /* XXX Can this happen _with_ a region reference? */
2500         if (list_empty(&hc->hc_item))
2501                 return;
2502
2503         if (region_uuid)
2504                 o2hb_region_dec_user(region_uuid);
2505
2506         down_write(&o2hb_callback_sem);
2507
2508         list_del_init(&hc->hc_item);
2509
2510         up_write(&o2hb_callback_sem);
2511 }
2512 EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
2513
2514 int o2hb_check_node_heartbeating(u8 node_num)
2515 {
2516         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2517
2518         o2hb_fill_node_map(testing_map, sizeof(testing_map));
2519         if (!test_bit(node_num, testing_map)) {
2520                 mlog(ML_HEARTBEAT,
2521                      "node (%u) does not have heartbeating enabled.\n",
2522                      node_num);
2523                 return 0;
2524         }
2525
2526         return 1;
2527 }
2528 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating);
2529
2530 int o2hb_check_node_heartbeating_no_sem(u8 node_num)
2531 {
2532         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2533
2534         spin_lock(&o2hb_live_lock);
2535         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2536         spin_unlock(&o2hb_live_lock);
2537         if (!test_bit(node_num, testing_map)) {
2538                 mlog(ML_HEARTBEAT,
2539                      "node (%u) does not have heartbeating enabled.\n",
2540                      node_num);
2541                 return 0;
2542         }
2543
2544         return 1;
2545 }
2546 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_no_sem);
2547
2548 int o2hb_check_node_heartbeating_from_callback(u8 node_num)
2549 {
2550         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2551
2552         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2553         if (!test_bit(node_num, testing_map)) {
2554                 mlog(ML_HEARTBEAT,
2555                      "node (%u) does not have heartbeating enabled.\n",
2556                      node_num);
2557                 return 0;
2558         }
2559
2560         return 1;
2561 }
2562 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_from_callback);
2563
2564 /* Makes sure our local node is configured with a node number, and is
2565  * heartbeating. */
2566 int o2hb_check_local_node_heartbeating(void)
2567 {
2568         u8 node_num;
2569
2570         /* if this node was set then we have networking */
2571         node_num = o2nm_this_node();
2572         if (node_num == O2NM_MAX_NODES) {
2573                 mlog(ML_HEARTBEAT, "this node has not been configured.\n");
2574                 return 0;
2575         }
2576
2577         return o2hb_check_node_heartbeating(node_num);
2578 }
2579 EXPORT_SYMBOL_GPL(o2hb_check_local_node_heartbeating);
2580
2581 /*
2582  * this is just a hack until we get the plumbing which flips file systems
2583  * read only and drops the hb ref instead of killing the node dead.
2584  */
2585 void o2hb_stop_all_regions(void)
2586 {
2587         struct o2hb_region *reg;
2588
2589         mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");
2590
2591         spin_lock(&o2hb_live_lock);
2592
2593         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
2594                 reg->hr_unclean_stop = 1;
2595
2596         spin_unlock(&o2hb_live_lock);
2597 }
2598 EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
2599
2600 int o2hb_get_all_regions(char *region_uuids, u8 max_regions)
2601 {
2602         struct o2hb_region *reg;
2603         int numregs = 0;
2604         char *p;
2605
2606         spin_lock(&o2hb_live_lock);
2607
2608         p = region_uuids;
2609         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2610                 if (reg->hr_item_dropped)
2611                         continue;
2612
2613                 mlog(0, "Region: %s\n", config_item_name(&reg->hr_item));
2614                 if (numregs < max_regions) {
2615                         memcpy(p, config_item_name(&reg->hr_item),
2616                                O2HB_MAX_REGION_NAME_LEN);
2617                         p += O2HB_MAX_REGION_NAME_LEN;
2618                 }
2619                 numregs++;
2620         }
2621
2622         spin_unlock(&o2hb_live_lock);
2623
2624         return numregs;
2625 }
2626 EXPORT_SYMBOL_GPL(o2hb_get_all_regions);
2627
2628 int o2hb_global_heartbeat_active(void)
2629 {
2630         return (o2hb_heartbeat_mode == O2HB_HEARTBEAT_GLOBAL);
2631 }
2632 EXPORT_SYMBOL(o2hb_global_heartbeat_active);