fs/ocfs2/cluster/heartbeat.c

   1 /* -*- mode: c; c-basic-offset: 8; -*-
   2  * vim: noexpandtab sw=8 ts=8 sts=0:
   3  *
   4  * Copyright (C) 2004, 2005 Oracle.  All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2 of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public
  17  * License along with this program; if not, write to the
  18  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19  * Boston, MA 021110-1307, USA.
  20  */
  21
  22 #include <linux/kernel.h>
  23 #include <linux/sched.h>
  24 #include <linux/jiffies.h>
  25 #include <linux/module.h>
  26 #include <linux/fs.h>
  27 #include <linux/bio.h>
  28 #include <linux/blkdev.h>
  29 #include <linux/delay.h>
  30 #include <linux/file.h>
  31 #include <linux/kthread.h>
  32 #include <linux/configfs.h>
  33 #include <linux/random.h>
  34 #include <linux/crc32.h>
  35 #include <linux/time.h>
  36 #include <linux/debugfs.h>
  37 #include <linux/slab.h>
  38 #include <linux/bitmap.h>
  39
  40 #include "heartbeat.h"
  41 #include "tcp.h"
  42 #include "nodemanager.h"
  43 #include "quorum.h"
  44
  45 #include "masklog.h"
  46
  47
  48 /*
  49  * The first heartbeat pass had one global thread that would serialize all hb
  50  * callback calls.  This global serializing sem should only be removed once
  51  * we've made sure that all callees can deal with being called concurrently
  52  * from multiple hb region threads.
  53  */
  54 static DECLARE_RWSEM(o2hb_callback_sem);
  55
  56 /*
  57  * multiple hb threads are watching multiple regions.  A node is live
  58  * whenever any of the threads sees activity from the node in its region.
  59  */
  60 static DEFINE_SPINLOCK(o2hb_live_lock);
  61 static struct list_head o2hb_live_slots[O2NM_MAX_NODES];
  62 static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
  63 static LIST_HEAD(o2hb_node_events);
  64 static DECLARE_WAIT_QUEUE_HEAD(o2hb_steady_queue);
  65
  66 /*
  67  * In global heartbeat, we maintain a series of region bitmaps.
  68  *      - o2hb_region_bitmap allows us to limit the region number to max region.
  69  *      - o2hb_live_region_bitmap tracks live regions (seen steady iterations).
  70  *      - o2hb_quorum_region_bitmap tracks live regions that have seen all nodes
  71  *              heartbeat on it.
  72  *      - o2hb_failed_region_bitmap tracks the regions that have seen io timeouts.
  73  */
  74 static unsigned long o2hb_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  75 static unsigned long o2hb_live_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  76 static unsigned long o2hb_quorum_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  77 static unsigned long o2hb_failed_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  78
  79 #define O2HB_DB_TYPE_LIVENODES          0
  80 #define O2HB_DB_TYPE_LIVEREGIONS        1
  81 #define O2HB_DB_TYPE_QUORUMREGIONS      2
  82 #define O2HB_DB_TYPE_FAILEDREGIONS      3
  83 #define O2HB_DB_TYPE_REGION_LIVENODES   4
  84 #define O2HB_DB_TYPE_REGION_NUMBER      5
  85 #define O2HB_DB_TYPE_REGION_ELAPSED_TIME        6
  86 #define O2HB_DB_TYPE_REGION_PINNED      7
  87 struct o2hb_debug_buf {
  88         int db_type;
  89         int db_size;
  90         int db_len;
  91         void *db_data;
  92 };
  93
  94 static struct o2hb_debug_buf *o2hb_db_livenodes;
  95 static struct o2hb_debug_buf *o2hb_db_liveregions;
  96 static struct o2hb_debug_buf *o2hb_db_quorumregions;
  97 static struct o2hb_debug_buf *o2hb_db_failedregions;
  98
  99 #define O2HB_DEBUG_DIR                  "o2hb"
 100 #define O2HB_DEBUG_LIVENODES            "livenodes"
 101 #define O2HB_DEBUG_LIVEREGIONS          "live_regions"
 102 #define O2HB_DEBUG_QUORUMREGIONS        "quorum_regions"
 103 #define O2HB_DEBUG_FAILEDREGIONS        "failed_regions"
 104 #define O2HB_DEBUG_REGION_NUMBER        "num"
 105 #define O2HB_DEBUG_REGION_ELAPSED_TIME  "elapsed_time_in_ms"
 106 #define O2HB_DEBUG_REGION_PINNED        "pinned"
 107
 108 static struct dentry *o2hb_debug_dir;
 109 static struct dentry *o2hb_debug_livenodes;
 110 static struct dentry *o2hb_debug_liveregions;
 111 static struct dentry *o2hb_debug_quorumregions;
 112 static struct dentry *o2hb_debug_failedregions;
 113
 114 static LIST_HEAD(o2hb_all_regions);
 115
 116 static struct o2hb_callback {
 117         struct list_head list;
 118 } o2hb_callbacks[O2HB_NUM_CB];
 119
 120 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type);
 121
 122 #define O2HB_DEFAULT_BLOCK_BITS       9
 123
 124 enum o2hb_heartbeat_modes {
 125         O2HB_HEARTBEAT_LOCAL            = 0,
 126         O2HB_HEARTBEAT_GLOBAL,
 127         O2HB_HEARTBEAT_NUM_MODES,
 128 };
 129
 130 char *o2hb_heartbeat_mode_desc[O2HB_HEARTBEAT_NUM_MODES] = {
 131                 "local",        /* O2HB_HEARTBEAT_LOCAL */
 132                 "global",       /* O2HB_HEARTBEAT_GLOBAL */
 133 };
 134
 135 unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
 136 unsigned int o2hb_heartbeat_mode = O2HB_HEARTBEAT_LOCAL;
 137
 138 /*
 139  * o2hb_dependent_users tracks the number of registered callbacks that depend
 140  * on heartbeat. o2net and o2dlm are two entities that register this callback.
 141  * However only o2dlm depends on the heartbeat. It does not want the heartbeat
 142  * to stop while a dlm domain is still active.
 143  */
 144 unsigned int o2hb_dependent_users;
 145
 146 /*
 147  * In global heartbeat mode, all regions are pinned if there are one or more
 148  * dependent users and the quorum region count is <= O2HB_PIN_CUT_OFF. All
 149  * regions are unpinned if the region count exceeds the cut off or the number
 150  * of dependent users falls to zero.
 151  */
 152 #define O2HB_PIN_CUT_OFF                3
 153
 154 /*
 155  * In local heartbeat mode, we assume the dlm domain name to be the same as
 156  * region uuid. This is true for domains created for the file system but not
 157  * necessarily true for userdlm domains. This is a known limitation.
 158  *
 159  * In global heartbeat mode, we pin/unpin all o2hb regions. This solution
 160  * works for both file system and userdlm domains.
 161  */
 162 static int o2hb_region_pin(const char *region_uuid);
 163 static void o2hb_region_unpin(const char *region_uuid);
 164
 165 /* Only sets a new threshold if there are no active regions.
 166  *
 167  * No locking or otherwise interesting code is required for reading
 168  * o2hb_dead_threshold as it can't change once regions are active and
 169  * it's not interesting to anyone until then anyway. */
 170 static void o2hb_dead_threshold_set(unsigned int threshold)
 171 {
 172         if (threshold > O2HB_MIN_DEAD_THRESHOLD) {
 173                 spin_lock(&o2hb_live_lock);
 174                 if (list_empty(&o2hb_all_regions))
 175                         o2hb_dead_threshold = threshold;
 176                 spin_unlock(&o2hb_live_lock);
 177         }
 178 }
 179
 180 static int o2hb_global_heartbeat_mode_set(unsigned int hb_mode)
 181 {
 182         int ret = -1;
 183
 184         if (hb_mode < O2HB_HEARTBEAT_NUM_MODES) {
 185                 spin_lock(&o2hb_live_lock);
 186                 if (list_empty(&o2hb_all_regions)) {
 187                         o2hb_heartbeat_mode = hb_mode;
 188                         ret = 0;
 189                 }
 190                 spin_unlock(&o2hb_live_lock);
 191         }
 192
 193         return ret;
 194 }
 195
 196 struct o2hb_node_event {
 197         struct list_head        hn_item;
 198         enum o2hb_callback_type hn_event_type;
 199         struct o2nm_node        *hn_node;
 200         int                     hn_node_num;
 201 };
 202
 203 struct o2hb_disk_slot {
 204         struct o2hb_disk_heartbeat_block *ds_raw_block;
 205         u8                      ds_node_num;
 206         u64                     ds_last_time;
 207         u64                     ds_last_generation;
 208         u16                     ds_equal_samples;
 209         u16                     ds_changed_samples;
 210         struct list_head        ds_live_item;
 211 };
 212
 213 /* each thread owns a region.. when we're asked to tear down the region
 214  * we ask the thread to stop, who cleans up the region */
 215 struct o2hb_region {
 216         struct config_item      hr_item;
 217
 218         struct list_head        hr_all_item;
 219         unsigned                hr_unclean_stop:1,
 220                                 hr_aborted_start:1,
 221                                 hr_item_pinned:1,
 222                                 hr_item_dropped:1;
 223
 224         /* protected by the hr_callback_sem */
 225         struct task_struct      *hr_task;
 226
 227         unsigned int            hr_blocks;
 228         unsigned long long      hr_start_block;
 229
 230         unsigned int            hr_block_bits;
 231         unsigned int            hr_block_bytes;
 232
 233         unsigned int            hr_slots_per_page;
 234         unsigned int            hr_num_pages;
 235
 236         struct page             **hr_slot_data;
 237         struct block_device     *hr_bdev;
 238         struct o2hb_disk_slot   *hr_slots;
 239
 240         /* live node map of this region */
 241         unsigned long           hr_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 242         unsigned int            hr_region_num;
 243
 244         struct dentry           *hr_debug_dir;
 245         struct dentry           *hr_debug_livenodes;
 246         struct dentry           *hr_debug_regnum;
 247         struct dentry           *hr_debug_elapsed_time;
 248         struct dentry           *hr_debug_pinned;
 249         struct o2hb_debug_buf   *hr_db_livenodes;
 250         struct o2hb_debug_buf   *hr_db_regnum;
 251         struct o2hb_debug_buf   *hr_db_elapsed_time;
 252         struct o2hb_debug_buf   *hr_db_pinned;
 253
 254         /* let the person setting up hb wait for it to return until it
 255          * has reached a 'steady' state.  This will be fixed when we have
 256          * a more complete api that doesn't lead to this sort of fragility. */
 257         atomic_t                hr_steady_iterations;
 258
 259         /* terminate o2hb thread if it does not reach steady state
 260          * (hr_steady_iterations == 0) within hr_unsteady_iterations */
 261         atomic_t                hr_unsteady_iterations;
 262
 263         char                    hr_dev_name[BDEVNAME_SIZE];
 264
 265         unsigned int            hr_timeout_ms;
 266
 267         /* randomized as the region goes up and down so that a node
 268          * recognizes a node going up and down in one iteration */
 269         u64                     hr_generation;
 270
 271         struct delayed_work     hr_write_timeout_work;
 272         unsigned long           hr_last_timeout_start;
 273
 274         /* Used during o2hb_check_slot to hold a copy of the block
 275          * being checked because we temporarily have to zero out the
 276          * crc field. */
 277         struct o2hb_disk_heartbeat_block *hr_tmp_block;
 278 };
 279
 280 struct o2hb_bio_wait_ctxt {
 281         atomic_t          wc_num_reqs;
 282         struct completion wc_io_complete;
 283         int               wc_error;
 284 };
 285
 286 static void o2hb_write_timeout(struct work_struct *work)
 287 {
 288         int failed, quorum;
 289         unsigned long flags;
 290         struct o2hb_region *reg =
 291                 container_of(work, struct o2hb_region,
 292                              hr_write_timeout_work.work);
 293
 294         mlog(ML_ERROR, "Heartbeat write timeout to device %s after %u "
 295              "milliseconds\n", reg->hr_dev_name,
 296              jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
 297
 298         if (o2hb_global_heartbeat_active()) {
 299                 spin_lock_irqsave(&o2hb_live_lock, flags);
 300                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 301                         set_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 302                 failed = bitmap_weight(o2hb_failed_region_bitmap,
 303                                         O2NM_MAX_REGIONS);
 304                 quorum = bitmap_weight(o2hb_quorum_region_bitmap,
 305                                         O2NM_MAX_REGIONS);
 306                 spin_unlock_irqrestore(&o2hb_live_lock, flags);
 307
 308                 mlog(ML_HEARTBEAT, "Number of regions %d, failed regions %d\n",
 309                      quorum, failed);
 310
 311                 /*
 312                  * Fence if the number of failed regions >= half the number
 313                  * of  quorum regions
 314                  */
 315                 if ((failed << 1) < quorum)
 316                         return;
 317         }
 318
 319         o2quo_disk_timeout();
 320 }
 321
 322 static void o2hb_arm_write_timeout(struct o2hb_region *reg)
 323 {
 324         /* Arm writeout only after thread reaches steady state */
 325         if (atomic_read(&reg->hr_steady_iterations) != 0)
 326                 return;
 327
 328         mlog(ML_HEARTBEAT, "Queue write timeout for %u ms\n",
 329              O2HB_MAX_WRITE_TIMEOUT_MS);
 330
 331         if (o2hb_global_heartbeat_active()) {
 332                 spin_lock(&o2hb_live_lock);
 333                 clear_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 334                 spin_unlock(&o2hb_live_lock);
 335         }
 336         cancel_delayed_work(&reg->hr_write_timeout_work);
 337         reg->hr_last_timeout_start = jiffies;
 338         schedule_delayed_work(&reg->hr_write_timeout_work,
 339                               msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
 340 }
 341
 342 static void o2hb_disarm_write_timeout(struct o2hb_region *reg)
 343 {
 344         cancel_delayed_work_sync(&reg->hr_write_timeout_work);
 345 }
 346
 347 static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
 348 {
 349         atomic_set(&wc->wc_num_reqs, 1);
 350         init_completion(&wc->wc_io_complete);
 351         wc->wc_error = 0;
 352 }
 353
 354 /* Used in error paths too */
 355 static inline void o2hb_bio_wait_dec(struct o2hb_bio_wait_ctxt *wc,
 356                                      unsigned int num)
 357 {
 358         /* sadly atomic_sub_and_test() isn't available on all platforms.  The
 359          * good news is that the fast path only completes one at a time */
 360         while(num--) {
 361                 if (atomic_dec_and_test(&wc->wc_num_reqs)) {
 362                         BUG_ON(num > 0);
 363                         complete(&wc->wc_io_complete);
 364                 }
 365         }
 366 }
 367
 368 static void o2hb_wait_on_io(struct o2hb_region *reg,
 369                             struct o2hb_bio_wait_ctxt *wc)
 370 {
 371         o2hb_bio_wait_dec(wc, 1);
 372         wait_for_completion(&wc->wc_io_complete);
 373 }
 374
 375 static void o2hb_bio_end_io(struct bio *bio,
 376                            int error)
 377 {
 378         struct o2hb_bio_wait_ctxt *wc = bio->bi_private;
 379
 380         if (error) {
 381                 mlog(ML_ERROR, "IO Error %d\n", error);
 382                 wc->wc_error = error;
 383         }
 384
 385         o2hb_bio_wait_dec(wc, 1);
 386         bio_put(bio);
 387 }
 388
 389 /* Setup a Bio to cover I/O against num_slots slots starting at
 390  * start_slot. */
 391 static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
 392                                       struct o2hb_bio_wait_ctxt *wc,
 393                                       unsigned int *current_slot,
 394                                       unsigned int max_slots)
 395 {
 396         int len, current_page;
 397         unsigned int vec_len, vec_start;
 398         unsigned int bits = reg->hr_block_bits;
 399         unsigned int spp = reg->hr_slots_per_page;
 400         unsigned int cs = *current_slot;
 401         struct bio *bio;
 402         struct page *page;
 403
 404         /* Testing has shown this allocation to take long enough under
 405          * GFP_KERNEL that the local node can get fenced. It would be
 406          * nicest if we could pre-allocate these bios and avoid this
 407          * all together. */
 408         bio = bio_alloc(GFP_ATOMIC, 16);
 409         if (!bio) {
 410                 mlog(ML_ERROR, "Could not alloc slots BIO!\n");
 411                 bio = ERR_PTR(-ENOMEM);
 412                 goto bail;
 413         }
 414
 415         /* Must put everything in 512 byte sectors for the bio... */
 416         bio->bi_sector = (reg->hr_start_block + cs) << (bits - 9);
 417         bio->bi_bdev = reg->hr_bdev;
 418         bio->bi_private = wc;
 419         bio->bi_end_io = o2hb_bio_end_io;
 420
 421         vec_start = (cs << bits) % PAGE_CACHE_SIZE;
 422         while(cs < max_slots) {
 423                 current_page = cs / spp;
 424                 page = reg->hr_slot_data[current_page];
 425
 426                 vec_len = min(PAGE_CACHE_SIZE - vec_start,
 427                               (max_slots-cs) * (PAGE_CACHE_SIZE/spp) );
 428
 429                 mlog(ML_HB_BIO, "page %d, vec_len = %u, vec_start = %u\n",
 430                      current_page, vec_len, vec_start);
 431
 432                 len = bio_add_page(bio, page, vec_len, vec_start);
 433                 if (len != vec_len) break;
 434
 435                 cs += vec_len / (PAGE_CACHE_SIZE/spp);
 436                 vec_start = 0;
 437         }
 438
 439 bail:
 440         *current_slot = cs;
 441         return bio;
 442 }
 443
 444 static int o2hb_read_slots(struct o2hb_region *reg,
 445                            unsigned int max_slots)
 446 {
 447         unsigned int current_slot=0;
 448         int status;
 449         struct o2hb_bio_wait_ctxt wc;
 450         struct bio *bio;
 451
 452         o2hb_bio_wait_init(&wc);
 453
 454         while(current_slot < max_slots) {
 455                 bio = o2hb_setup_one_bio(reg, &wc, &current_slot, max_slots);
 456                 if (IS_ERR(bio)) {
 457                         status = PTR_ERR(bio);
 458                         mlog_errno(status);
 459                         goto bail_and_wait;
 460                 }
 461
 462                 atomic_inc(&wc.wc_num_reqs);
 463                 submit_bio(READ, bio);
 464         }
 465
 466         status = 0;
 467
 468 bail_and_wait:
 469         o2hb_wait_on_io(reg, &wc);
 470         if (wc.wc_error && !status)
 471                 status = wc.wc_error;
 472
 473         return status;
 474 }
 475
 476 static int o2hb_issue_node_write(struct o2hb_region *reg,
 477                                  struct o2hb_bio_wait_ctxt *write_wc)
 478 {
 479         int status;
 480         unsigned int slot;
 481         struct bio *bio;
 482
 483         o2hb_bio_wait_init(write_wc);
 484
 485         slot = o2nm_this_node();
 486
 487         bio = o2hb_setup_one_bio(reg, write_wc, &slot, slot+1);
 488         if (IS_ERR(bio)) {
 489                 status = PTR_ERR(bio);
 490                 mlog_errno(status);
 491                 goto bail;
 492         }
 493
 494         atomic_inc(&write_wc->wc_num_reqs);
 495         submit_bio(WRITE_SYNC, bio);
 496
 497         status = 0;
 498 bail:
 499         return status;
 500 }
 501
 502 static u32 o2hb_compute_block_crc_le(struct o2hb_region *reg,
 503                                      struct o2hb_disk_heartbeat_block *hb_block)
 504 {
 505         __le32 old_cksum;
 506         u32 ret;
 507
 508         /* We want to compute the block crc with a 0 value in the
 509          * hb_cksum field. Save it off here and replace after the
 510          * crc. */
 511         old_cksum = hb_block->hb_cksum;
 512         hb_block->hb_cksum = 0;
 513
 514         ret = crc32_le(0, (unsigned char *) hb_block, reg->hr_block_bytes);
 515
 516         hb_block->hb_cksum = old_cksum;
 517
 518         return ret;
 519 }
 520
 521 static void o2hb_dump_slot(struct o2hb_disk_heartbeat_block *hb_block)
 522 {
 523         mlog(ML_ERROR, "Dump slot information: seq = 0x%llx, node = %u, "
 524              "cksum = 0x%x, generation 0x%llx\n",
 525              (long long)le64_to_cpu(hb_block->hb_seq),
 526              hb_block->hb_node, le32_to_cpu(hb_block->hb_cksum),
 527              (long long)le64_to_cpu(hb_block->hb_generation));
 528 }
 529
 530 static int o2hb_verify_crc(struct o2hb_region *reg,
 531                            struct o2hb_disk_heartbeat_block *hb_block)
 532 {
 533         u32 read, computed;
 534
 535         read = le32_to_cpu(hb_block->hb_cksum);
 536         computed = o2hb_compute_block_crc_le(reg, hb_block);
 537
 538         return read == computed;
 539 }
 540
 541 /*
 542  * Compare the slot data with what we wrote in the last iteration.
 543  * If the match fails, print an appropriate error message. This is to
 544  * detect errors like... another node hearting on the same slot,
 545  * flaky device that is losing writes, etc.
 546  * Returns 1 if check succeeds, 0 otherwise.
 547  */
 548 static int o2hb_check_own_slot(struct o2hb_region *reg)
 549 {
 550         struct o2hb_disk_slot *slot;
 551         struct o2hb_disk_heartbeat_block *hb_block;
 552         char *errstr;
 553
 554         slot = &reg->hr_slots[o2nm_this_node()];
 555         /* Don't check on our 1st timestamp */
 556         if (!slot->ds_last_time)
 557                 return 0;
 558
 559         hb_block = slot->ds_raw_block;
 560         if (le64_to_cpu(hb_block->hb_seq) == slot->ds_last_time &&
 561             le64_to_cpu(hb_block->hb_generation) == slot->ds_last_generation &&
 562             hb_block->hb_node == slot->ds_node_num)
 563                 return 1;
 564
 565 #define ERRSTR1         "Another node is heartbeating on device"
 566 #define ERRSTR2         "Heartbeat generation mismatch on device"
 567 #define ERRSTR3         "Heartbeat sequence mismatch on device"
 568
 569         if (hb_block->hb_node != slot->ds_node_num)
 570                 errstr = ERRSTR1;
 571         else if (le64_to_cpu(hb_block->hb_generation) !=
 572                  slot->ds_last_generation)
 573                 errstr = ERRSTR2;
 574         else
 575                 errstr = ERRSTR3;
 576
 577         mlog(ML_ERROR, "%s (%s): expected(%u:0x%llx, 0x%llx), "
 578              "ondisk(%u:0x%llx, 0x%llx)\n", errstr, reg->hr_dev_name,
 579              slot->ds_node_num, (unsigned long long)slot->ds_last_generation,
 580              (unsigned long long)slot->ds_last_time, hb_block->hb_node,
 581              (unsigned long long)le64_to_cpu(hb_block->hb_generation),
 582              (unsigned long long)le64_to_cpu(hb_block->hb_seq));
 583
 584         return 0;
 585 }
 586
 587 static inline void o2hb_prepare_block(struct o2hb_region *reg,
 588                                       u64 generation)
 589 {
 590         int node_num;
 591         u64 cputime;
 592         struct o2hb_disk_slot *slot;
 593         struct o2hb_disk_heartbeat_block *hb_block;
 594
 595         node_num = o2nm_this_node();
 596         slot = &reg->hr_slots[node_num];
 597
 598         hb_block = (struct o2hb_disk_heartbeat_block *)slot->ds_raw_block;
 599         memset(hb_block, 0, reg->hr_block_bytes);
 600         /* TODO: time stuff */
 601         cputime = CURRENT_TIME.tv_sec;
 602         if (!cputime)
 603                 cputime = 1;
 604
 605         hb_block->hb_seq = cpu_to_le64(cputime);
 606         hb_block->hb_node = node_num;
 607         hb_block->hb_generation = cpu_to_le64(generation);
 608         hb_block->hb_dead_ms = cpu_to_le32(o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS);
 609
 610         /* This step must always happen last! */
 611         hb_block->hb_cksum = cpu_to_le32(o2hb_compute_block_crc_le(reg,
 612                                                                    hb_block));
 613
 614         mlog(ML_HB_BIO, "our node generation = 0x%llx, cksum = 0x%x\n",
 615              (long long)generation,
 616              le32_to_cpu(hb_block->hb_cksum));
 617 }
 618
 619 static void o2hb_fire_callbacks(struct o2hb_callback *hbcall,
 620                                 struct o2nm_node *node,
 621                                 int idx)
 622 {
 623         struct o2hb_callback_func *f;
 624
 625         list_for_each_entry(f, &hbcall->list, hc_item) {
 626                 mlog(ML_HEARTBEAT, "calling funcs %p\n", f);
 627                 (f->hc_func)(node, idx, f->hc_data);
 628         }
 629 }
 630
 631 /* Will run the list in order until we process the passed event */
 632 static void o2hb_run_event_list(struct o2hb_node_event *queued_event)
 633 {
 634         struct o2hb_callback *hbcall;
 635         struct o2hb_node_event *event;
 636
 637         /* Holding callback sem assures we don't alter the callback
 638          * lists when doing this, and serializes ourselves with other
 639          * processes wanting callbacks. */
 640         down_write(&o2hb_callback_sem);
 641
 642         spin_lock(&o2hb_live_lock);
 643         while (!list_empty(&o2hb_node_events)
 644                && !list_empty(&queued_event->hn_item)) {
 645                 event = list_entry(o2hb_node_events.next,
 646                                    struct o2hb_node_event,
 647                                    hn_item);
 648                 list_del_init(&event->hn_item);
 649                 spin_unlock(&o2hb_live_lock);
 650
 651                 mlog(ML_HEARTBEAT, "Node %s event for %d\n",
 652                      event->hn_event_type == O2HB_NODE_UP_CB ? "UP" : "DOWN",
 653                      event->hn_node_num);
 654
 655                 hbcall = hbcall_from_type(event->hn_event_type);
 656
 657                 /* We should *never* have gotten on to the list with a
 658                  * bad type... This isn't something that we should try
 659                  * to recover from. */
 660                 BUG_ON(IS_ERR(hbcall));
 661
 662                 o2hb_fire_callbacks(hbcall, event->hn_node, event->hn_node_num);
 663
 664                 spin_lock(&o2hb_live_lock);
 665         }
 666         spin_unlock(&o2hb_live_lock);
 667
 668         up_write(&o2hb_callback_sem);
 669 }
 670
 671 static void o2hb_queue_node_event(struct o2hb_node_event *event,
 672                                   enum o2hb_callback_type type,
 673                                   struct o2nm_node *node,
 674                                   int node_num)
 675 {
 676         assert_spin_locked(&o2hb_live_lock);
 677
 678         BUG_ON((!node) && (type != O2HB_NODE_DOWN_CB));
 679
 680         event->hn_event_type = type;
 681         event->hn_node = node;
 682         event->hn_node_num = node_num;
 683
 684         mlog(ML_HEARTBEAT, "Queue node %s event for node %d\n",
 685              type == O2HB_NODE_UP_CB ? "UP" : "DOWN", node_num);
 686
 687         list_add_tail(&event->hn_item, &o2hb_node_events);
 688 }
 689
 690 static void o2hb_shutdown_slot(struct o2hb_disk_slot *slot)
 691 {
 692         struct o2hb_node_event event =
 693                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 694         struct o2nm_node *node;
 695         int queued = 0;
 696
 697         node = o2nm_get_node_by_num(slot->ds_node_num);
 698         if (!node)
 699                 return;
 700
 701         spin_lock(&o2hb_live_lock);
 702         if (!list_empty(&slot->ds_live_item)) {
 703                 mlog(ML_HEARTBEAT, "Shutdown, node %d leaves region\n",
 704                      slot->ds_node_num);
 705
 706                 list_del_init(&slot->ds_live_item);
 707
 708                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 709                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 710
 711                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB, node,
 712                                               slot->ds_node_num);
 713                         queued = 1;
 714                 }
 715         }
 716         spin_unlock(&o2hb_live_lock);
 717
 718         if (queued)
 719                 o2hb_run_event_list(&event);
 720
 721         o2nm_node_put(node);
 722 }
 723
 724 static void o2hb_set_quorum_device(struct o2hb_region *reg)
 725 {
 726         if (!o2hb_global_heartbeat_active())
 727                 return;
 728
 729         /* Prevent race with o2hb_heartbeat_group_drop_item() */
 730         if (kthread_should_stop())
 731                 return;
 732
 733         /* Tag region as quorum only after thread reaches steady state */
 734         if (atomic_read(&reg->hr_steady_iterations) != 0)
 735                 return;
 736
 737         spin_lock(&o2hb_live_lock);
 738
 739         if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 740                 goto unlock;
 741
 742         /*
 743          * A region can be added to the quorum only when it sees all
 744          * live nodes heartbeat on it. In other words, the region has been
 745          * added to all nodes.
 746          */
 747         if (memcmp(reg->hr_live_node_bitmap, o2hb_live_node_bitmap,
 748                    sizeof(o2hb_live_node_bitmap)))
 749                 goto unlock;
 750
 751         printk(KERN_NOTICE "o2hb: Region %s (%s) is now a quorum device\n",
 752                config_item_name(&reg->hr_item), reg->hr_dev_name);
 753
 754         set_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
 755
 756         /*
 757          * If global heartbeat active, unpin all regions if the
 758          * region count > CUT_OFF
 759          */
 760         if (bitmap_weight(o2hb_quorum_region_bitmap,
 761                            O2NM_MAX_REGIONS) > O2HB_PIN_CUT_OFF)
 762                 o2hb_region_unpin(NULL);
 763 unlock:
 764         spin_unlock(&o2hb_live_lock);
 765 }
 766
 767 static int o2hb_check_slot(struct o2hb_region *reg,
 768                            struct o2hb_disk_slot *slot)
 769 {
 770         int changed = 0, gen_changed = 0;
 771         struct o2hb_node_event event =
 772                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 773         struct o2nm_node *node;
 774         struct o2hb_disk_heartbeat_block *hb_block = reg->hr_tmp_block;
 775         u64 cputime;
 776         unsigned int dead_ms = o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS;
 777         unsigned int slot_dead_ms;
 778         int tmp;
 779         int queued = 0;
 780
 781         memcpy(hb_block, slot->ds_raw_block, reg->hr_block_bytes);
 782
 783         /*
 784          * If a node is no longer configured but is still in the livemap, we
 785          * may need to clear that bit from the livemap.
 786          */
 787         node = o2nm_get_node_by_num(slot->ds_node_num);
 788         if (!node) {
 789                 spin_lock(&o2hb_live_lock);
 790                 tmp = test_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 791                 spin_unlock(&o2hb_live_lock);
 792                 if (!tmp)
 793                         return 0;
 794         }
 795
 796         if (!o2hb_verify_crc(reg, hb_block)) {
 797                 /* all paths from here will drop o2hb_live_lock for
 798                  * us. */
 799                 spin_lock(&o2hb_live_lock);
 800
 801                 /* Don't print an error on the console in this case -
 802                  * a freshly formatted heartbeat area will not have a
 803                  * crc set on it. */
 804                 if (list_empty(&slot->ds_live_item))
 805                         goto out;
 806
 807                 /* The node is live but pushed out a bad crc. We
 808                  * consider it a transient miss but don't populate any
 809                  * other values as they may be junk. */
 810                 mlog(ML_ERROR, "Node %d has written a bad crc to %s\n",
 811                      slot->ds_node_num, reg->hr_dev_name);
 812                 o2hb_dump_slot(hb_block);
 813
 814                 slot->ds_equal_samples++;
 815                 goto fire_callbacks;
 816         }
 817
 818         /* we don't care if these wrap.. the state transitions below
 819          * clear at the right places */
 820         cputime = le64_to_cpu(hb_block->hb_seq);
 821         if (slot->ds_last_time != cputime)
 822                 slot->ds_changed_samples++;
 823         else
 824                 slot->ds_equal_samples++;
 825         slot->ds_last_time = cputime;
 826
 827         /* The node changed heartbeat generations. We assume this to
 828          * mean it dropped off but came back before we timed out. We
 829          * want to consider it down for the time being but don't want
 830          * to lose any changed_samples state we might build up to
 831          * considering it live again. */
 832         if (slot->ds_last_generation != le64_to_cpu(hb_block->hb_generation)) {
 833                 gen_changed = 1;
 834                 slot->ds_equal_samples = 0;
 835                 mlog(ML_HEARTBEAT, "Node %d changed generation (0x%llx "
 836                      "to 0x%llx)\n", slot->ds_node_num,
 837                      (long long)slot->ds_last_generation,
 838                      (long long)le64_to_cpu(hb_block->hb_generation));
 839         }
 840
 841         slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
 842
 843         mlog(ML_HEARTBEAT, "Slot %d gen 0x%llx cksum 0x%x "
 844              "seq %llu last %llu changed %u equal %u\n",
 845              slot->ds_node_num, (long long)slot->ds_last_generation,
 846              le32_to_cpu(hb_block->hb_cksum),
 847              (unsigned long long)le64_to_cpu(hb_block->hb_seq),
 848              (unsigned long long)slot->ds_last_time, slot->ds_changed_samples,
 849              slot->ds_equal_samples);
 850
 851         spin_lock(&o2hb_live_lock);
 852
 853 fire_callbacks:
 854         /* dead nodes only come to life after some number of
 855          * changes at any time during their dead time */
 856         if (list_empty(&slot->ds_live_item) &&
 857             slot->ds_changed_samples >= O2HB_LIVE_THRESHOLD) {
 858                 mlog(ML_HEARTBEAT, "Node %d (id 0x%llx) joined my region\n",
 859                      slot->ds_node_num, (long long)slot->ds_last_generation);
 860
 861                 set_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 862
 863                 /* first on the list generates a callback */
 864                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 865                         mlog(ML_HEARTBEAT, "o2hb: Add node %d to live nodes "
 866                              "bitmap\n", slot->ds_node_num);
 867                         set_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 868
 869                         o2hb_queue_node_event(&event, O2HB_NODE_UP_CB, node,
 870                                               slot->ds_node_num);
 871
 872                         changed = 1;
 873                         queued = 1;
 874                 }
 875
 876                 list_add_tail(&slot->ds_live_item,
 877                               &o2hb_live_slots[slot->ds_node_num]);
 878
 879                 slot->ds_equal_samples = 0;
 880
 881                 /* We want to be sure that all nodes agree on the
 882                  * number of milliseconds before a node will be
 883                  * considered dead. The self-fencing timeout is
 884                  * computed from this value, and a discrepancy might
 885                  * result in heartbeat calling a node dead when it
 886                  * hasn't self-fenced yet. */
 887                 slot_dead_ms = le32_to_cpu(hb_block->hb_dead_ms);
 888                 if (slot_dead_ms && slot_dead_ms != dead_ms) {
 889                         /* TODO: Perhaps we can fail the region here. */
 890                         mlog(ML_ERROR, "Node %d on device %s has a dead count "
 891                              "of %u ms, but our count is %u ms.\n"
 892                              "Please double check your configuration values "
 893                              "for 'O2CB_HEARTBEAT_THRESHOLD'\n",
 894                              slot->ds_node_num, reg->hr_dev_name, slot_dead_ms,
 895                              dead_ms);
 896                 }
 897                 goto out;
 898         }
 899
 900         /* if the list is dead, we're done.. */
 901         if (list_empty(&slot->ds_live_item))
 902                 goto out;
 903
 904         /* live nodes only go dead after enough consequtive missed
 905          * samples..  reset the missed counter whenever we see
 906          * activity */
 907         if (slot->ds_equal_samples >= o2hb_dead_threshold || gen_changed) {
 908                 mlog(ML_HEARTBEAT, "Node %d left my region\n",
 909                      slot->ds_node_num);
 910
 911                 clear_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 912
 913                 /* last off the live_slot generates a callback */
 914                 list_del_init(&slot->ds_live_item);
 915                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 916                         mlog(ML_HEARTBEAT, "o2hb: Remove node %d from live "
 917                              "nodes bitmap\n", slot->ds_node_num);
 918                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 919
 920                         /* node can be null */
 921                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB,
 922                                               node, slot->ds_node_num);
 923
 924                         changed = 1;
 925                         queued = 1;
 926                 }
 927
 928                 /* We don't clear this because the node is still
 929                  * actually writing new blocks. */
 930                 if (!gen_changed)
 931                         slot->ds_changed_samples = 0;
 932                 goto out;
 933         }
 934         if (slot->ds_changed_samples) {
 935                 slot->ds_changed_samples = 0;
 936                 slot->ds_equal_samples = 0;
 937         }
 938 out:
 939         spin_unlock(&o2hb_live_lock);
 940
 941         if (queued)
 942                 o2hb_run_event_list(&event);
 943
 944         if (node)
 945                 o2nm_node_put(node);
 946         return changed;
 947 }
 948
 949 /* This could be faster if we just implmented a find_last_bit, but I
 950  * don't think the circumstances warrant it. */
 951 static int o2hb_highest_node(unsigned long *nodes,
 952                              int numbits)
 953 {
 954         int highest, node;
 955
 956         highest = numbits;
 957         node = -1;
 958         while ((node = find_next_bit(nodes, numbits, node + 1)) != -1) {
 959                 if (node >= numbits)
 960                         break;
 961
 962                 highest = node;
 963         }
 964
 965         return highest;
 966 }
 967
 968 static int o2hb_do_disk_heartbeat(struct o2hb_region *reg)
 969 {
 970         int i, ret, highest_node;
 971         int membership_change = 0, own_slot_ok = 0;
 972         unsigned long configured_nodes[BITS_TO_LONGS(O2NM_MAX_NODES)];
 973         unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 974         struct o2hb_bio_wait_ctxt write_wc;
 975
 976         ret = o2nm_configured_node_map(configured_nodes,
 977                                        sizeof(configured_nodes));
 978         if (ret) {
 979                 mlog_errno(ret);
 980                 goto bail;
 981         }
 982
 983         /*
 984          * If a node is not configured but is in the livemap, we still need
 985          * to read the slot so as to be able to remove it from the livemap.
 986          */
 987         o2hb_fill_node_map(live_node_bitmap, sizeof(live_node_bitmap));
 988         i = -1;
 989         while ((i = find_next_bit(live_node_bitmap,
 990                                   O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
 991                 set_bit(i, configured_nodes);
 992         }
 993
 994         highest_node = o2hb_highest_node(configured_nodes, O2NM_MAX_NODES);
 995         if (highest_node >= O2NM_MAX_NODES) {
 996                 mlog(ML_NOTICE, "o2hb: No configured nodes found!\n");
 997                 ret = -EINVAL;
 998                 goto bail;
 999         }
1000
1001         /* No sense in reading the slots of nodes that don't exist
1002          * yet. Of course, if the node definitions have holes in them
1003          * then we're reading an empty slot anyway... Consider this
1004          * best-effort. */
1005         ret = o2hb_read_slots(reg, highest_node + 1);
1006         if (ret < 0) {
1007                 mlog_errno(ret);
1008                 goto bail;
1009         }
1010
1011         /* With an up to date view of the slots, we can check that no
1012          * other node has been improperly configured to heartbeat in
1013          * our slot. */
1014         own_slot_ok = o2hb_check_own_slot(reg);
1015
1016         /* fill in the proper info for our next heartbeat */
1017         o2hb_prepare_block(reg, reg->hr_generation);
1018
1019         ret = o2hb_issue_node_write(reg, &write_wc);
1020         if (ret < 0) {
1021                 mlog_errno(ret);
1022                 goto bail;
1023         }
1024
1025         i = -1;
1026         while((i = find_next_bit(configured_nodes,
1027                                  O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
1028                 membership_change |= o2hb_check_slot(reg, &reg->hr_slots[i]);
1029         }
1030
1031         /*
1032          * We have to be sure we've advertised ourselves on disk
1033          * before we can go to steady state.  This ensures that
1034          * people we find in our steady state have seen us.
1035          */
1036         o2hb_wait_on_io(reg, &write_wc);
1037         if (write_wc.wc_error) {
1038                 /* Do not re-arm the write timeout on I/O error - we
1039                  * can't be sure that the new block ever made it to
1040                  * disk */
1041                 mlog(ML_ERROR, "Write error %d on device \"%s\"\n",
1042                      write_wc.wc_error, reg->hr_dev_name);
1043                 ret = write_wc.wc_error;
1044                 goto bail;
1045         }
1046
1047         /* Skip disarming the timeout if own slot has stale/bad data */
1048         if (own_slot_ok) {
1049                 o2hb_set_quorum_device(reg);
1050                 o2hb_arm_write_timeout(reg);
1051         }
1052
1053 bail:
1054         /* let the person who launched us know when things are steady */
1055         if (atomic_read(&reg->hr_steady_iterations) != 0) {
1056                 if (!ret && own_slot_ok && !membership_change) {
1057                         if (atomic_dec_and_test(&reg->hr_steady_iterations))
1058                                 wake_up(&o2hb_steady_queue);
1059                 }
1060         }
1061
1062         if (atomic_read(&reg->hr_steady_iterations) != 0) {
1063                 if (atomic_dec_and_test(&reg->hr_unsteady_iterations)) {
1064                         printk(KERN_NOTICE "o2hb: Unable to stabilize "
1065                                "heartbeart on region %s (%s)\n",
1066                                config_item_name(&reg->hr_item),
1067                                reg->hr_dev_name);
1068                         atomic_set(&reg->hr_steady_iterations, 0);
1069                         reg->hr_aborted_start = 1;
1070                         wake_up(&o2hb_steady_queue);
1071                         ret = -EIO;
1072                 }
1073         }
1074
1075         return ret;
1076 }
1077
1078 /* Subtract b from a, storing the result in a. a *must* have a larger
1079  * value than b. */
1080 static void o2hb_tv_subtract(struct timeval *a,
1081                              struct timeval *b)
1082 {
1083         /* just return 0 when a is after b */
1084         if (a->tv_sec < b->tv_sec ||
1085             (a->tv_sec == b->tv_sec && a->tv_usec < b->tv_usec)) {
1086                 a->tv_sec = 0;
1087                 a->tv_usec = 0;
1088                 return;
1089         }
1090
1091         a->tv_sec -= b->tv_sec;
1092         a->tv_usec -= b->tv_usec;
1093         while ( a->tv_usec < 0 ) {
1094                 a->tv_sec--;
1095                 a->tv_usec += 1000000;
1096         }
1097 }
1098
1099 static unsigned int o2hb_elapsed_msecs(struct timeval *start,
1100                                        struct timeval *end)
1101 {
1102         struct timeval res = *end;
1103
1104         o2hb_tv_subtract(&res, start);
1105
1106         return res.tv_sec * 1000 + res.tv_usec / 1000;
1107 }
1108
1109 /*
1110  * we ride the region ref that the region dir holds.  before the region
1111  * dir is removed and drops it ref it will wait to tear down this
1112  * thread.
1113  */
1114 static int o2hb_thread(void *data)
1115 {
1116         int i, ret;
1117         struct o2hb_region *reg = data;
1118         struct o2hb_bio_wait_ctxt write_wc;
1119         struct timeval before_hb, after_hb;
1120         unsigned int elapsed_msec;
1121
1122         mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n");
1123
1124         set_user_nice(current, -20);
1125
1126         /* Pin node */
1127         o2nm_depend_this_node();
1128
1129         while (!kthread_should_stop() &&
1130                !reg->hr_unclean_stop && !reg->hr_aborted_start) {
1131                 /* We track the time spent inside
1132                  * o2hb_do_disk_heartbeat so that we avoid more than
1133                  * hr_timeout_ms between disk writes. On busy systems
1134                  * this should result in a heartbeat which is less
1135                  * likely to time itself out. */
1136                 do_gettimeofday(&before_hb);
1137
1138                 ret = o2hb_do_disk_heartbeat(reg);
1139
1140                 do_gettimeofday(&after_hb);
1141                 elapsed_msec = o2hb_elapsed_msecs(&before_hb, &after_hb);
1142
1143                 mlog(ML_HEARTBEAT,
1144                      "start = %lu.%lu, end = %lu.%lu, msec = %u\n",
1145                      before_hb.tv_sec, (unsigned long) before_hb.tv_usec,
1146                      after_hb.tv_sec, (unsigned long) after_hb.tv_usec,
1147                      elapsed_msec);
1148
1149                 if (!kthread_should_stop() &&
1150                     elapsed_msec < reg->hr_timeout_ms) {
1151                         /* the kthread api has blocked signals for us so no
1152                          * need to record the return value. */
1153                         msleep_interruptible(reg->hr_timeout_ms - elapsed_msec);
1154                 }
1155         }
1156
1157         o2hb_disarm_write_timeout(reg);
1158
1159         /* unclean stop is only used in very bad situation */
1160         for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
1161                 o2hb_shutdown_slot(&reg->hr_slots[i]);
1162
1163         /* Explicit down notification - avoid forcing the other nodes
1164          * to timeout on this region when we could just as easily
1165          * write a clear generation - thus indicating to them that
1166          * this node has left this region.
1167          */
1168         if (!reg->hr_unclean_stop && !reg->hr_aborted_start) {
1169                 o2hb_prepare_block(reg, 0);
1170                 ret = o2hb_issue_node_write(reg, &write_wc);
1171                 if (ret == 0)
1172                         o2hb_wait_on_io(reg, &write_wc);
1173                 else
1174                         mlog_errno(ret);
1175         }
1176
1177         /* Unpin node */
1178         o2nm_undepend_this_node();
1179
1180         mlog(ML_HEARTBEAT|ML_KTHREAD, "o2hb thread exiting\n");
1181
1182         return 0;
1183 }
1184
1185 #ifdef CONFIG_DEBUG_FS
1186 static int o2hb_debug_open(struct inode *inode, struct file *file)
1187 {
1188         struct o2hb_debug_buf *db = inode->i_private;
1189         struct o2hb_region *reg;
1190         unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1191         unsigned long lts;
1192         char *buf = NULL;
1193         int i = -1;
1194         int out = 0;
1195
1196         /* max_nodes should be the largest bitmap we pass here */
1197         BUG_ON(sizeof(map) < db->db_size);
1198
1199         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1200         if (!buf)
1201                 goto bail;
1202
1203         switch (db->db_type) {
1204         case O2HB_DB_TYPE_LIVENODES:
1205         case O2HB_DB_TYPE_LIVEREGIONS:
1206         case O2HB_DB_TYPE_QUORUMREGIONS:
1207         case O2HB_DB_TYPE_FAILEDREGIONS:
1208                 spin_lock(&o2hb_live_lock);
1209                 memcpy(map, db->db_data, db->db_size);
1210                 spin_unlock(&o2hb_live_lock);
1211                 break;
1212
1213         case O2HB_DB_TYPE_REGION_LIVENODES:
1214                 spin_lock(&o2hb_live_lock);
1215                 reg = (struct o2hb_region *)db->db_data;
1216                 memcpy(map, reg->hr_live_node_bitmap, db->db_size);
1217                 spin_unlock(&o2hb_live_lock);
1218                 break;
1219
1220         case O2HB_DB_TYPE_REGION_NUMBER:
1221                 reg = (struct o2hb_region *)db->db_data;
1222                 out += snprintf(buf + out, PAGE_SIZE - out, "%d\n",
1223                                 reg->hr_region_num);
1224                 goto done;
1225
1226         case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
1227                 reg = (struct o2hb_region *)db->db_data;
1228                 lts = reg->hr_last_timeout_start;
1229                 /* If 0, it has never been set before */
1230                 if (lts)
1231                         lts = jiffies_to_msecs(jiffies - lts);
1232                 out += snprintf(buf + out, PAGE_SIZE - out, "%lu\n", lts);
1233                 goto done;
1234
1235         case O2HB_DB_TYPE_REGION_PINNED:
1236                 reg = (struct o2hb_region *)db->db_data;
1237                 out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
1238                                 !!reg->hr_item_pinned);
1239                 goto done;
1240
1241         default:
1242                 goto done;
1243         }
1244
1245         while ((i = find_next_bit(map, db->db_len, i + 1)) < db->db_len)
1246                 out += snprintf(buf + out, PAGE_SIZE - out, "%d ", i);
1247         out += snprintf(buf + out, PAGE_SIZE - out, "\n");
1248
1249 done:
1250         i_size_write(inode, out);
1251
1252         file->private_data = buf;
1253
1254         return 0;
1255 bail:
1256         return -ENOMEM;
1257 }
1258
1259 static int o2hb_debug_release(struct inode *inode, struct file *file)
1260 {
1261         kfree(file->private_data);
1262         return 0;
1263 }
1264
1265 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1266                                  size_t nbytes, loff_t *ppos)
1267 {
1268         return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
1269                                        i_size_read(file->f_mapping->host));
1270 }
1271 #else
1272 static int o2hb_debug_open(struct inode *inode, struct file *file)
1273 {
1274         return 0;
1275 }
1276 static int o2hb_debug_release(struct inode *inode, struct file *file)
1277 {
1278         return 0;
1279 }
1280 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1281                                size_t nbytes, loff_t *ppos)
1282 {
1283         return 0;
1284 }
1285 #endif  /* CONFIG_DEBUG_FS */
1286
1287 static const struct file_operations o2hb_debug_fops = {
1288         .open =         o2hb_debug_open,
1289         .release =      o2hb_debug_release,
1290         .read =         o2hb_debug_read,
1291         .llseek =       generic_file_llseek,
1292 };
1293
1294 void o2hb_exit(void)
1295 {
1296         kfree(o2hb_db_livenodes);
1297         kfree(o2hb_db_liveregions);
1298         kfree(o2hb_db_quorumregions);
1299         kfree(o2hb_db_failedregions);
1300         debugfs_remove(o2hb_debug_failedregions);
1301         debugfs_remove(o2hb_debug_quorumregions);
1302         debugfs_remove(o2hb_debug_liveregions);
1303         debugfs_remove(o2hb_debug_livenodes);
1304         debugfs_remove(o2hb_debug_dir);
1305 }
1306
1307 static struct dentry *o2hb_debug_create(const char *name, struct dentry *dir,
1308                                         struct o2hb_debug_buf **db, int db_len,
1309                                         int type, int size, int len, void *data)
1310 {
1311         *db = kmalloc(db_len, GFP_KERNEL);
1312         if (!*db)
1313                 return NULL;
1314
1315         (*db)->db_type = type;
1316         (*db)->db_size = size;
1317         (*db)->db_len = len;
1318         (*db)->db_data = data;
1319
1320         return debugfs_create_file(name, S_IFREG|S_IRUSR, dir, *db,
1321                                    &o2hb_debug_fops);
1322 }
1323
1324 static int o2hb_debug_init(void)
1325 {
1326         int ret = -ENOMEM;
1327
1328         o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
1329         if (!o2hb_debug_dir) {
1330                 mlog_errno(ret);
1331                 goto bail;
1332         }
1333
1334         o2hb_debug_livenodes = o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1335                                                  o2hb_debug_dir,
1336                                                  &o2hb_db_livenodes,
1337                                                  sizeof(*o2hb_db_livenodes),
1338                                                  O2HB_DB_TYPE_LIVENODES,
1339                                                  sizeof(o2hb_live_node_bitmap),
1340                                                  O2NM_MAX_NODES,
1341                                                  o2hb_live_node_bitmap);
1342         if (!o2hb_debug_livenodes) {
1343                 mlog_errno(ret);
1344                 goto bail;
1345         }
1346
1347         o2hb_debug_liveregions = o2hb_debug_create(O2HB_DEBUG_LIVEREGIONS,
1348                                                    o2hb_debug_dir,
1349                                                    &o2hb_db_liveregions,
1350                                                    sizeof(*o2hb_db_liveregions),
1351                                                    O2HB_DB_TYPE_LIVEREGIONS,
1352                                                    sizeof(o2hb_live_region_bitmap),
1353                                                    O2NM_MAX_REGIONS,
1354                                                    o2hb_live_region_bitmap);
1355         if (!o2hb_debug_liveregions) {
1356                 mlog_errno(ret);
1357                 goto bail;
1358         }
1359
1360         o2hb_debug_quorumregions =
1361                         o2hb_debug_create(O2HB_DEBUG_QUORUMREGIONS,
1362                                           o2hb_debug_dir,
1363                                           &o2hb_db_quorumregions,
1364                                           sizeof(*o2hb_db_quorumregions),
1365                                           O2HB_DB_TYPE_QUORUMREGIONS,
1366                                           sizeof(o2hb_quorum_region_bitmap),
1367                                           O2NM_MAX_REGIONS,
1368                                           o2hb_quorum_region_bitmap);
1369         if (!o2hb_debug_quorumregions) {
1370                 mlog_errno(ret);
1371                 goto bail;
1372         }
1373
1374         o2hb_debug_failedregions =
1375                         o2hb_debug_create(O2HB_DEBUG_FAILEDREGIONS,
1376                                           o2hb_debug_dir,
1377                                           &o2hb_db_failedregions,
1378                                           sizeof(*o2hb_db_failedregions),
1379                                           O2HB_DB_TYPE_FAILEDREGIONS,
1380                                           sizeof(o2hb_failed_region_bitmap),
1381                                           O2NM_MAX_REGIONS,
1382                                           o2hb_failed_region_bitmap);
1383         if (!o2hb_debug_failedregions) {
1384                 mlog_errno(ret);
1385                 goto bail;
1386         }
1387
1388         ret = 0;
1389 bail:
1390         if (ret)
1391                 o2hb_exit();
1392
1393         return ret;
1394 }
1395
1396 int o2hb_init(void)
1397 {
1398         int i;
1399
1400         for (i = 0; i < ARRAY_SIZE(o2hb_callbacks); i++)
1401                 INIT_LIST_HEAD(&o2hb_callbacks[i].list);
1402
1403         for (i = 0; i < ARRAY_SIZE(o2hb_live_slots); i++)
1404                 INIT_LIST_HEAD(&o2hb_live_slots[i]);
1405
1406         INIT_LIST_HEAD(&o2hb_node_events);
1407
1408         memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
1409         memset(o2hb_region_bitmap, 0, sizeof(o2hb_region_bitmap));
1410         memset(o2hb_live_region_bitmap, 0, sizeof(o2hb_live_region_bitmap));
1411         memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
1412         memset(o2hb_failed_region_bitmap, 0, sizeof(o2hb_failed_region_bitmap));
1413
1414         o2hb_dependent_users = 0;
1415
1416         return o2hb_debug_init();
1417 }
1418
1419 /* if we're already in a callback then we're already serialized by the sem */
1420 static void o2hb_fill_node_map_from_callback(unsigned long *map,
1421                                              unsigned bytes)
1422 {
1423         BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1424
1425         memcpy(map, &o2hb_live_node_bitmap, bytes);
1426 }
1427
1428 /*
1429  * get a map of all nodes that are heartbeating in any regions
1430  */
1431 void o2hb_fill_node_map(unsigned long *map, unsigned bytes)
1432 {
1433         /* callers want to serialize this map and callbacks so that they
1434          * can trust that they don't miss nodes coming to the party */
1435         down_read(&o2hb_callback_sem);
1436         spin_lock(&o2hb_live_lock);
1437         o2hb_fill_node_map_from_callback(map, bytes);
1438         spin_unlock(&o2hb_live_lock);
1439         up_read(&o2hb_callback_sem);
1440 }
1441 EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
1442
1443 /*
1444  * heartbeat configfs bits.  The heartbeat set is a default set under
1445  * the cluster set in nodemanager.c.
1446  */
1447
1448 static struct o2hb_region *to_o2hb_region(struct config_item *item)
1449 {
1450         return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
1451 }
1452
1453 /* drop_item only drops its ref after killing the thread, nothing should
1454  * be using the region anymore.  this has to clean up any state that
1455  * attributes might have built up. */
1456 static void o2hb_region_release(struct config_item *item)
1457 {
1458         int i;
1459         struct page *page;
1460         struct o2hb_region *reg = to_o2hb_region(item);
1461
1462         mlog(ML_HEARTBEAT, "hb region release (%s)\n", reg->hr_dev_name);
1463
1464         kfree(reg->hr_tmp_block);
1465
1466         if (reg->hr_slot_data) {
1467                 for (i = 0; i < reg->hr_num_pages; i++) {
1468                         page = reg->hr_slot_data[i];
1469                         if (page)
1470                                 __free_page(page);
1471                 }
1472                 kfree(reg->hr_slot_data);
1473         }
1474
1475         if (reg->hr_bdev)
1476                 blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1477
1478         kfree(reg->hr_slots);
1479
1480         kfree(reg->hr_db_regnum);
1481         kfree(reg->hr_db_livenodes);
1482         debugfs_remove(reg->hr_debug_livenodes);
1483         debugfs_remove(reg->hr_debug_regnum);
1484         debugfs_remove(reg->hr_debug_elapsed_time);
1485         debugfs_remove(reg->hr_debug_pinned);
1486         debugfs_remove(reg->hr_debug_dir);
1487
1488         spin_lock(&o2hb_live_lock);
1489         list_del(&reg->hr_all_item);
1490         spin_unlock(&o2hb_live_lock);
1491
1492         kfree(reg);
1493 }
1494
1495 static int o2hb_read_block_input(struct o2hb_region *reg,
1496                                  const char *page,
1497                                  size_t count,
1498                                  unsigned long *ret_bytes,
1499                                  unsigned int *ret_bits)
1500 {
1501         unsigned long bytes;
1502         char *p = (char *)page;
1503
1504         bytes = simple_strtoul(p, &p, 0);
1505         if (!p || (*p && (*p != '\n')))
1506                 return -EINVAL;
1507
1508         /* Heartbeat and fs min / max block sizes are the same. */
1509         if (bytes > 4096 || bytes < 512)
1510                 return -ERANGE;
1511         if (hweight16(bytes) != 1)
1512                 return -EINVAL;
1513
1514         if (ret_bytes)
1515                 *ret_bytes = bytes;
1516         if (ret_bits)
1517                 *ret_bits = ffs(bytes) - 1;
1518
1519         return 0;
1520 }
1521
1522 static ssize_t o2hb_region_block_bytes_read(struct o2hb_region *reg,
1523                                             char *page)
1524 {
1525         return sprintf(page, "%u\n", reg->hr_block_bytes);
1526 }
1527
1528 static ssize_t o2hb_region_block_bytes_write(struct o2hb_region *reg,
1529                                              const char *page,
1530                                              size_t count)
1531 {
1532         int status;
1533         unsigned long block_bytes;
1534         unsigned int block_bits;
1535
1536         if (reg->hr_bdev)
1537                 return -EINVAL;
1538
1539         status = o2hb_read_block_input(reg, page, count,
1540                                        &block_bytes, &block_bits);
1541         if (status)
1542                 return status;
1543
1544         reg->hr_block_bytes = (unsigned int)block_bytes;
1545         reg->hr_block_bits = block_bits;
1546
1547         return count;
1548 }
1549
1550 static ssize_t o2hb_region_start_block_read(struct o2hb_region *reg,
1551                                             char *page)
1552 {
1553         return sprintf(page, "%llu\n", reg->hr_start_block);
1554 }
1555
1556 static ssize_t o2hb_region_start_block_write(struct o2hb_region *reg,
1557                                              const char *page,
1558                                              size_t count)
1559 {
1560         unsigned long long tmp;
1561         char *p = (char *)page;
1562
1563         if (reg->hr_bdev)
1564                 return -EINVAL;
1565
1566         tmp = simple_strtoull(p, &p, 0);
1567         if (!p || (*p && (*p != '\n')))
1568                 return -EINVAL;
1569
1570         reg->hr_start_block = tmp;
1571
1572         return count;
1573 }
1574
1575 static ssize_t o2hb_region_blocks_read(struct o2hb_region *reg,
1576                                        char *page)
1577 {
1578         return sprintf(page, "%d\n", reg->hr_blocks);
1579 }
1580
1581 static ssize_t o2hb_region_blocks_write(struct o2hb_region *reg,
1582                                         const char *page,
1583                                         size_t count)
1584 {
1585         unsigned long tmp;
1586         char *p = (char *)page;
1587
1588         if (reg->hr_bdev)
1589                 return -EINVAL;
1590
1591         tmp = simple_strtoul(p, &p, 0);
1592         if (!p || (*p && (*p != '\n')))
1593                 return -EINVAL;
1594
1595         if (tmp > O2NM_MAX_NODES || tmp == 0)
1596                 return -ERANGE;
1597
1598         reg->hr_blocks = (unsigned int)tmp;
1599
1600         return count;
1601 }
1602
1603 static ssize_t o2hb_region_dev_read(struct o2hb_region *reg,
1604                                     char *page)
1605 {
1606         unsigned int ret = 0;
1607
1608         if (reg->hr_bdev)
1609                 ret = sprintf(page, "%s\n", reg->hr_dev_name);
1610
1611         return ret;
1612 }
1613
1614 static void o2hb_init_region_params(struct o2hb_region *reg)
1615 {
1616         reg->hr_slots_per_page = PAGE_CACHE_SIZE >> reg->hr_block_bits;
1617         reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
1618
1619         mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
1620              reg->hr_start_block, reg->hr_blocks);
1621         mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
1622              reg->hr_block_bytes, reg->hr_block_bits);
1623         mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
1624         mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
1625 }
1626
1627 static int o2hb_map_slot_data(struct o2hb_region *reg)
1628 {
1629         int i, j;
1630         unsigned int last_slot;
1631         unsigned int spp = reg->hr_slots_per_page;
1632         struct page *page;
1633         char *raw;
1634         struct o2hb_disk_slot *slot;
1635
1636         reg->hr_tmp_block = kmalloc(reg->hr_block_bytes, GFP_KERNEL);
1637         if (reg->hr_tmp_block == NULL) {
1638                 mlog_errno(-ENOMEM);
1639                 return -ENOMEM;
1640         }
1641
1642         reg->hr_slots = kcalloc(reg->hr_blocks,
1643                                 sizeof(struct o2hb_disk_slot), GFP_KERNEL);
1644         if (reg->hr_slots == NULL) {
1645                 mlog_errno(-ENOMEM);
1646                 return -ENOMEM;
1647         }
1648
1649         for(i = 0; i < reg->hr_blocks; i++) {
1650                 slot = &reg->hr_slots[i];
1651                 slot->ds_node_num = i;
1652                 INIT_LIST_HEAD(&slot->ds_live_item);
1653                 slot->ds_raw_block = NULL;
1654         }
1655
1656         reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
1657         mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
1658                            "at %u blocks per page\n",
1659              reg->hr_num_pages, reg->hr_blocks, spp);
1660
1661         reg->hr_slot_data = kcalloc(reg->hr_num_pages, sizeof(struct page *),
1662                                     GFP_KERNEL);
1663         if (!reg->hr_slot_data) {
1664                 mlog_errno(-ENOMEM);
1665                 return -ENOMEM;
1666         }
1667
1668         for(i = 0; i < reg->hr_num_pages; i++) {
1669                 page = alloc_page(GFP_KERNEL);
1670                 if (!page) {
1671                         mlog_errno(-ENOMEM);
1672                         return -ENOMEM;
1673                 }
1674
1675                 reg->hr_slot_data[i] = page;
1676
1677                 last_slot = i * spp;
1678                 raw = page_address(page);
1679                 for (j = 0;
1680                      (j < spp) && ((j + last_slot) < reg->hr_blocks);
1681                      j++) {
1682                         BUG_ON((j + last_slot) >= reg->hr_blocks);
1683
1684                         slot = &reg->hr_slots[j + last_slot];
1685                         slot->ds_raw_block =
1686                                 (struct o2hb_disk_heartbeat_block *) raw;
1687
1688                         raw += reg->hr_block_bytes;
1689                 }
1690         }
1691
1692         return 0;
1693 }
1694
1695 /* Read in all the slots available and populate the tracking
1696  * structures so that we can start with a baseline idea of what's
1697  * there. */
1698 static int o2hb_populate_slot_data(struct o2hb_region *reg)
1699 {
1700         int ret, i;
1701         struct o2hb_disk_slot *slot;
1702         struct o2hb_disk_heartbeat_block *hb_block;
1703
1704         ret = o2hb_read_slots(reg, reg->hr_blocks);
1705         if (ret) {
1706                 mlog_errno(ret);
1707                 goto out;
1708         }
1709
1710         /* We only want to get an idea of the values initially in each
1711          * slot, so we do no verification - o2hb_check_slot will
1712          * actually determine if each configured slot is valid and
1713          * whether any values have changed. */
1714         for(i = 0; i < reg->hr_blocks; i++) {
1715                 slot = &reg->hr_slots[i];
1716                 hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
1717
1718                 /* Only fill the values that o2hb_check_slot uses to
1719                  * determine changing slots */
1720                 slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
1721                 slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
1722         }
1723
1724 out:
1725         return ret;
1726 }
1727
1728 /* this is acting as commit; we set up all of hr_bdev and hr_task or nothing */
1729 static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
1730                                      const char *page,
1731                                      size_t count)
1732 {
1733         struct task_struct *hb_task;
1734         long fd;
1735         int sectsize;
1736         char *p = (char *)page;
1737         struct fd f;
1738         struct inode *inode;
1739         ssize_t ret = -EINVAL;
1740         int live_threshold;
1741
1742         if (reg->hr_bdev)
1743                 goto out;
1744
1745         /* We can't heartbeat without having had our node number
1746          * configured yet. */
1747         if (o2nm_this_node() == O2NM_MAX_NODES)
1748                 goto out;
1749
1750         fd = simple_strtol(p, &p, 0);
1751         if (!p || (*p && (*p != '\n')))
1752                 goto out;
1753
1754         if (fd < 0 || fd >= INT_MAX)
1755                 goto out;
1756
1757         f = fdget(fd);
1758         if (f.file == NULL)
1759                 goto out;
1760
1761         if (reg->hr_blocks == 0 || reg->hr_start_block == 0 ||
1762             reg->hr_block_bytes == 0)
1763                 goto out2;
1764
1765         inode = igrab(f.file->f_mapping->host);
1766         if (inode == NULL)
1767                 goto out2;
1768
1769         if (!S_ISBLK(inode->i_mode))
1770                 goto out3;
1771
1772         reg->hr_bdev = I_BDEV(f.file->f_mapping->host);
1773         ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ, NULL);
1774         if (ret) {
1775                 reg->hr_bdev = NULL;
1776                 goto out3;
1777         }
1778         inode = NULL;
1779
1780         bdevname(reg->hr_bdev, reg->hr_dev_name);
1781
1782         sectsize = bdev_logical_block_size(reg->hr_bdev);
1783         if (sectsize != reg->hr_block_bytes) {
1784                 mlog(ML_ERROR,
1785                      "blocksize %u incorrect for device, expected %d",
1786                      reg->hr_block_bytes, sectsize);
1787                 ret = -EINVAL;
1788                 goto out3;
1789         }
1790
1791         o2hb_init_region_params(reg);
1792
1793         /* Generation of zero is invalid */
1794         do {
1795                 get_random_bytes(&reg->hr_generation,
1796                                  sizeof(reg->hr_generation));
1797         } while (reg->hr_generation == 0);
1798
1799         ret = o2hb_map_slot_data(reg);
1800         if (ret) {
1801                 mlog_errno(ret);
1802                 goto out3;
1803         }
1804
1805         ret = o2hb_populate_slot_data(reg);
1806         if (ret) {
1807                 mlog_errno(ret);
1808                 goto out3;
1809         }
1810
1811         INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
1812
1813         /*
1814          * A node is considered live after it has beat LIVE_THRESHOLD
1815          * times.  We're not steady until we've given them a chance
1816          * _after_ our first read.
1817          * The default threshold is bare minimum so as to limit the delay
1818          * during mounts. For global heartbeat, the threshold doubled for the
1819          * first region.
1820          */
1821         live_threshold = O2HB_LIVE_THRESHOLD;
1822         if (o2hb_global_heartbeat_active()) {
1823                 spin_lock(&o2hb_live_lock);
1824                 if (bitmap_weight(o2hb_region_bitmap, O2NM_MAX_REGIONS) == 1)
1825                         live_threshold <<= 1;
1826                 spin_unlock(&o2hb_live_lock);
1827         }
1828         ++live_threshold;
1829         atomic_set(&reg->hr_steady_iterations, live_threshold);
1830         /* unsteady_iterations is double the steady_iterations */
1831         atomic_set(&reg->hr_unsteady_iterations, (live_threshold << 1));
1832
1833         hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
1834                               reg->hr_item.ci_name);
1835         if (IS_ERR(hb_task)) {
1836                 ret = PTR_ERR(hb_task);
1837                 mlog_errno(ret);
1838                 goto out3;
1839         }
1840
1841         spin_lock(&o2hb_live_lock);
1842         reg->hr_task = hb_task;
1843         spin_unlock(&o2hb_live_lock);
1844
1845         ret = wait_event_interruptible(o2hb_steady_queue,
1846                                 atomic_read(&reg->hr_steady_iterations) == 0);
1847         if (ret) {
1848                 atomic_set(&reg->hr_steady_iterations, 0);
1849                 reg->hr_aborted_start = 1;
1850         }
1851
1852         if (reg->hr_aborted_start) {
1853                 ret = -EIO;
1854                 goto out3;
1855         }
1856
1857         /* Ok, we were woken.  Make sure it wasn't by drop_item() */
1858         spin_lock(&o2hb_live_lock);
1859         hb_task = reg->hr_task;
1860         if (o2hb_global_heartbeat_active())
1861                 set_bit(reg->hr_region_num, o2hb_live_region_bitmap);
1862         spin_unlock(&o2hb_live_lock);
1863
1864         if (hb_task)
1865                 ret = count;
1866         else
1867                 ret = -EIO;
1868
1869         if (hb_task && o2hb_global_heartbeat_active())
1870                 printk(KERN_NOTICE "o2hb: Heartbeat started on region %s (%s)\n",
1871                        config_item_name(&reg->hr_item), reg->hr_dev_name);
1872
1873 out3:
1874         iput(inode);
1875 out2:
1876         fdput(f);
1877 out:
1878         if (ret < 0) {
1879                 if (reg->hr_bdev) {
1880                         blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1881                         reg->hr_bdev = NULL;
1882                 }
1883         }
1884         return ret;
1885 }
1886
1887 static ssize_t o2hb_region_pid_read(struct o2hb_region *reg,
1888                                       char *page)
1889 {
1890         pid_t pid = 0;
1891
1892         spin_lock(&o2hb_live_lock);
1893         if (reg->hr_task)
1894                 pid = task_pid_nr(reg->hr_task);
1895         spin_unlock(&o2hb_live_lock);
1896
1897         if (!pid)
1898                 return 0;
1899
1900         return sprintf(page, "%u\n", pid);
1901 }
1902
1903 struct o2hb_region_attribute {
1904         struct configfs_attribute attr;
1905         ssize_t (*show)(struct o2hb_region *, char *);
1906         ssize_t (*store)(struct o2hb_region *, const char *, size_t);
1907 };
1908
1909 static struct o2hb_region_attribute o2hb_region_attr_block_bytes = {
1910         .attr   = { .ca_owner = THIS_MODULE,
1911                     .ca_name = "block_bytes",
1912                     .ca_mode = S_IRUGO | S_IWUSR },
1913         .show   = o2hb_region_block_bytes_read,
1914         .store  = o2hb_region_block_bytes_write,
1915 };
1916
1917 static struct o2hb_region_attribute o2hb_region_attr_start_block = {
1918         .attr   = { .ca_owner = THIS_MODULE,
1919                     .ca_name = "start_block",
1920                     .ca_mode = S_IRUGO | S_IWUSR },
1921         .show   = o2hb_region_start_block_read,
1922         .store  = o2hb_region_start_block_write,
1923 };
1924
1925 static struct o2hb_region_attribute o2hb_region_attr_blocks = {
1926         .attr   = { .ca_owner = THIS_MODULE,
1927                     .ca_name = "blocks",
1928                     .ca_mode = S_IRUGO | S_IWUSR },
1929         .show   = o2hb_region_blocks_read,
1930         .store  = o2hb_region_blocks_write,
1931 };
1932
1933 static struct o2hb_region_attribute o2hb_region_attr_dev = {
1934         .attr   = { .ca_owner = THIS_MODULE,
1935                     .ca_name = "dev",
1936                     .ca_mode = S_IRUGO | S_IWUSR },
1937         .show   = o2hb_region_dev_read,
1938         .store  = o2hb_region_dev_write,
1939 };
1940
1941 static struct o2hb_region_attribute o2hb_region_attr_pid = {
1942        .attr   = { .ca_owner = THIS_MODULE,
1943                    .ca_name = "pid",
1944                    .ca_mode = S_IRUGO | S_IRUSR },
1945        .show   = o2hb_region_pid_read,
1946 };
1947
1948 static struct configfs_attribute *o2hb_region_attrs[] = {
1949         &o2hb_region_attr_block_bytes.attr,
1950         &o2hb_region_attr_start_block.attr,
1951         &o2hb_region_attr_blocks.attr,
1952         &o2hb_region_attr_dev.attr,
1953         &o2hb_region_attr_pid.attr,
1954         NULL,
1955 };
1956
1957 static ssize_t o2hb_region_show(struct config_item *item,
1958                                 struct configfs_attribute *attr,
1959                                 char *page)
1960 {
1961         struct o2hb_region *reg = to_o2hb_region(item);
1962         struct o2hb_region_attribute *o2hb_region_attr =
1963                 container_of(attr, struct o2hb_region_attribute, attr);
1964         ssize_t ret = 0;
1965
1966         if (o2hb_region_attr->show)
1967                 ret = o2hb_region_attr->show(reg, page);
1968         return ret;
1969 }
1970
1971 static ssize_t o2hb_region_store(struct config_item *item,
1972                                  struct configfs_attribute *attr,
1973                                  const char *page, size_t count)
1974 {
1975         struct o2hb_region *reg = to_o2hb_region(item);
1976         struct o2hb_region_attribute *o2hb_region_attr =
1977                 container_of(attr, struct o2hb_region_attribute, attr);
1978         ssize_t ret = -EINVAL;
1979
1980         if (o2hb_region_attr->store)
1981                 ret = o2hb_region_attr->store(reg, page, count);
1982         return ret;
1983 }
1984
1985 static struct configfs_item_operations o2hb_region_item_ops = {
1986         .release                = o2hb_region_release,
1987         .show_attribute         = o2hb_region_show,
1988         .store_attribute        = o2hb_region_store,
1989 };
1990
1991 static struct config_item_type o2hb_region_type = {
1992         .ct_item_ops    = &o2hb_region_item_ops,
1993         .ct_attrs       = o2hb_region_attrs,
1994         .ct_owner       = THIS_MODULE,
1995 };
1996
1997 /* heartbeat set */
1998
1999 struct o2hb_heartbeat_group {
2000         struct config_group hs_group;
2001         /* some stuff? */
2002 };
2003
2004 static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
2005 {
2006         return group ?
2007                 container_of(group, struct o2hb_heartbeat_group, hs_group)
2008                 : NULL;
2009 }
2010
2011 static int o2hb_debug_region_init(struct o2hb_region *reg, struct dentry *dir)
2012 {
2013         int ret = -ENOMEM;
2014
2015         reg->hr_debug_dir =
2016                 debugfs_create_dir(config_item_name(&reg->hr_item), dir);
2017         if (!reg->hr_debug_dir) {
2018                 mlog_errno(ret);
2019                 goto bail;
2020         }
2021
2022         reg->hr_debug_livenodes =
2023                         o2hb_debug_create(O2HB_DEBUG_LIVENODES,
2024                                           reg->hr_debug_dir,
2025                                           &(reg->hr_db_livenodes),
2026                                           sizeof(*(reg->hr_db_livenodes)),
2027                                           O2HB_DB_TYPE_REGION_LIVENODES,
2028                                           sizeof(reg->hr_live_node_bitmap),
2029                                           O2NM_MAX_NODES, reg);
2030         if (!reg->hr_debug_livenodes) {
2031                 mlog_errno(ret);
2032                 goto bail;
2033         }
2034
2035         reg->hr_debug_regnum =
2036                         o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER,
2037                                           reg->hr_debug_dir,
2038                                           &(reg->hr_db_regnum),
2039                                           sizeof(*(reg->hr_db_regnum)),
2040                                           O2HB_DB_TYPE_REGION_NUMBER,
2041                                           0, O2NM_MAX_NODES, reg);
2042         if (!reg->hr_debug_regnum) {
2043                 mlog_errno(ret);
2044                 goto bail;
2045         }
2046
2047         reg->hr_debug_elapsed_time =
2048                         o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME,
2049                                           reg->hr_debug_dir,
2050                                           &(reg->hr_db_elapsed_time),
2051                                           sizeof(*(reg->hr_db_elapsed_time)),
2052                                           O2HB_DB_TYPE_REGION_ELAPSED_TIME,
2053                                           0, 0, reg);
2054         if (!reg->hr_debug_elapsed_time) {
2055                 mlog_errno(ret);
2056                 goto bail;
2057         }
2058
2059         reg->hr_debug_pinned =
2060                         o2hb_debug_create(O2HB_DEBUG_REGION_PINNED,
2061                                           reg->hr_debug_dir,
2062                                           &(reg->hr_db_pinned),
2063                                           sizeof(*(reg->hr_db_pinned)),
2064                                           O2HB_DB_TYPE_REGION_PINNED,
2065                                           0, 0, reg);
2066         if (!reg->hr_debug_pinned) {
2067                 mlog_errno(ret);
2068                 goto bail;
2069         }
2070
2071         ret = 0;
2072 bail:
2073         return ret;
2074 }
2075
2076 static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
2077                                                           const char *name)
2078 {
2079         struct o2hb_region *reg = NULL;
2080         int ret;
2081
2082         reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
2083         if (reg == NULL)
2084                 return ERR_PTR(-ENOMEM);
2085
2086         if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
2087                 ret = -ENAMETOOLONG;
2088                 goto free;
2089         }
2090
2091         spin_lock(&o2hb_live_lock);
2092         reg->hr_region_num = 0;
2093         if (o2hb_global_heartbeat_active()) {
2094                 reg->hr_region_num = find_first_zero_bit(o2hb_region_bitmap,
2095                                                          O2NM_MAX_REGIONS);
2096                 if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
2097                         spin_unlock(&o2hb_live_lock);
2098                         ret = -EFBIG;
2099                         goto free;
2100                 }
2101                 set_bit(reg->hr_region_num, o2hb_region_bitmap);
2102         }
2103         list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
2104         spin_unlock(&o2hb_live_lock);
2105
2106         config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
2107
2108         ret = o2hb_debug_region_init(reg, o2hb_debug_dir);
2109         if (ret) {
2110                 config_item_put(&reg->hr_item);
2111                 goto free;
2112         }
2113
2114         return &reg->hr_item;
2115 free:
2116         kfree(reg);
2117         return ERR_PTR(ret);
2118 }
2119
2120 static void o2hb_heartbeat_group_drop_item(struct config_group *group,
2121                                            struct config_item *item)
2122 {
2123         struct task_struct *hb_task;
2124         struct o2hb_region *reg = to_o2hb_region(item);
2125         int quorum_region = 0;
2126
2127         /* stop the thread when the user removes the region dir */
2128         spin_lock(&o2hb_live_lock);
2129         hb_task = reg->hr_task;
2130         reg->hr_task = NULL;
2131         reg->hr_item_dropped = 1;
2132         spin_unlock(&o2hb_live_lock);
2133
2134         if (hb_task)
2135                 kthread_stop(hb_task);
2136
2137         if (o2hb_global_heartbeat_active()) {
2138                 spin_lock(&o2hb_live_lock);
2139                 clear_bit(reg->hr_region_num, o2hb_region_bitmap);
2140                 clear_bit(reg->hr_region_num, o2hb_live_region_bitmap);
2141                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
2142                         quorum_region = 1;
2143                 clear_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
2144                 spin_unlock(&o2hb_live_lock);
2145                 printk(KERN_NOTICE "o2hb: Heartbeat %s on region %s (%s)\n",
2146                        ((atomic_read(&reg->hr_steady_iterations) == 0) ?
2147                         "stopped" : "start aborted"), config_item_name(item),
2148                        reg->hr_dev_name);
2149         }
2150
2151         /*
2152          * If we're racing a dev_write(), we need to wake them.  They will
2153          * check reg->hr_task
2154          */
2155         if (atomic_read(&reg->hr_steady_iterations) != 0) {
2156                 reg->hr_aborted_start = 1;
2157                 atomic_set(&reg->hr_steady_iterations, 0);
2158                 wake_up(&o2hb_steady_queue);
2159         }
2160
2161         config_item_put(item);
2162
2163         if (!o2hb_global_heartbeat_active() || !quorum_region)
2164                 return;
2165
2166         /*
2167          * If global heartbeat active and there are dependent users,
2168          * pin all regions if quorum region count <= CUT_OFF
2169          */
2170         spin_lock(&o2hb_live_lock);
2171
2172         if (!o2hb_dependent_users)
2173                 goto unlock;
2174
2175         if (bitmap_weight(o2hb_quorum_region_bitmap,
2176                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2177                 o2hb_region_pin(NULL);
2178
2179 unlock:
2180         spin_unlock(&o2hb_live_lock);
2181 }
2182
2183 struct o2hb_heartbeat_group_attribute {
2184         struct configfs_attribute attr;
2185         ssize_t (*show)(struct o2hb_heartbeat_group *, char *);
2186         ssize_t (*store)(struct o2hb_heartbeat_group *, const char *, size_t);
2187 };
2188
2189 static ssize_t o2hb_heartbeat_group_show(struct config_item *item,
2190                                          struct configfs_attribute *attr,
2191                                          char *page)
2192 {
2193         struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
2194         struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
2195                 container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
2196         ssize_t ret = 0;
2197
2198         if (o2hb_heartbeat_group_attr->show)
2199                 ret = o2hb_heartbeat_group_attr->show(reg, page);
2200         return ret;
2201 }
2202
2203 static ssize_t o2hb_heartbeat_group_store(struct config_item *item,
2204                                           struct configfs_attribute *attr,
2205                                           const char *page, size_t count)
2206 {
2207         struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
2208         struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
2209                 container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
2210         ssize_t ret = -EINVAL;
2211
2212         if (o2hb_heartbeat_group_attr->store)
2213                 ret = o2hb_heartbeat_group_attr->store(reg, page, count);
2214         return ret;
2215 }
2216
2217 static ssize_t o2hb_heartbeat_group_threshold_show(struct o2hb_heartbeat_group *group,
2218                                                      char *page)
2219 {
2220         return sprintf(page, "%u\n", o2hb_dead_threshold);
2221 }
2222
2223 static ssize_t o2hb_heartbeat_group_threshold_store(struct o2hb_heartbeat_group *group,
2224                                                     const char *page,
2225                                                     size_t count)
2226 {
2227         unsigned long tmp;
2228         char *p = (char *)page;
2229
2230         tmp = simple_strtoul(p, &p, 10);
2231         if (!p || (*p && (*p != '\n')))
2232                 return -EINVAL;
2233
2234         /* this will validate ranges for us. */
2235         o2hb_dead_threshold_set((unsigned int) tmp);
2236
2237         return count;
2238 }
2239
2240 static
2241 ssize_t o2hb_heartbeat_group_mode_show(struct o2hb_heartbeat_group *group,
2242                                        char *page)
2243 {
2244         return sprintf(page, "%s\n",
2245                        o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
2246 }
2247
2248 static
2249 ssize_t o2hb_heartbeat_group_mode_store(struct o2hb_heartbeat_group *group,
2250                                         const char *page, size_t count)
2251 {
2252         unsigned int i;
2253         int ret;
2254         size_t len;
2255
2256         len = (page[count - 1] == '\n') ? count - 1 : count;
2257         if (!len)
2258                 return -EINVAL;
2259
2260         for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
2261                 if (strnicmp(page, o2hb_heartbeat_mode_desc[i], len))
2262                         continue;
2263
2264                 ret = o2hb_global_heartbeat_mode_set(i);
2265                 if (!ret)
2266                         printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
2267                                o2hb_heartbeat_mode_desc[i]);
2268                 return count;
2269         }
2270
2271         return -EINVAL;
2272
2273 }
2274
2275 static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_threshold = {
2276         .attr   = { .ca_owner = THIS_MODULE,
2277                     .ca_name = "dead_threshold",
2278                     .ca_mode = S_IRUGO | S_IWUSR },
2279         .show   = o2hb_heartbeat_group_threshold_show,
2280         .store  = o2hb_heartbeat_group_threshold_store,
2281 };
2282
2283 static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_mode = {
2284         .attr   = { .ca_owner = THIS_MODULE,
2285                 .ca_name = "mode",
2286                 .ca_mode = S_IRUGO | S_IWUSR },
2287         .show   = o2hb_heartbeat_group_mode_show,
2288         .store  = o2hb_heartbeat_group_mode_store,
2289 };
2290
2291 static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
2292         &o2hb_heartbeat_group_attr_threshold.attr,
2293         &o2hb_heartbeat_group_attr_mode.attr,
2294         NULL,
2295 };
2296
2297 static struct configfs_item_operations o2hb_heartbeat_group_item_ops = {
2298         .show_attribute         = o2hb_heartbeat_group_show,
2299         .store_attribute        = o2hb_heartbeat_group_store,
2300 };
2301
2302 static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
2303         .make_item      = o2hb_heartbeat_group_make_item,
2304         .drop_item      = o2hb_heartbeat_group_drop_item,
2305 };
2306
2307 static struct config_item_type o2hb_heartbeat_group_type = {
2308         .ct_group_ops   = &o2hb_heartbeat_group_group_ops,
2309         .ct_item_ops    = &o2hb_heartbeat_group_item_ops,
2310         .ct_attrs       = o2hb_heartbeat_group_attrs,
2311         .ct_owner       = THIS_MODULE,
2312 };
2313
2314 /* this is just here to avoid touching group in heartbeat.h which the
2315  * entire damn world #includes */
2316 struct config_group *o2hb_alloc_hb_set(void)
2317 {
2318         struct o2hb_heartbeat_group *hs = NULL;
2319         struct config_group *ret = NULL;
2320
2321         hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
2322         if (hs == NULL)
2323                 goto out;
2324
2325         config_group_init_type_name(&hs->hs_group, "heartbeat",
2326                                     &o2hb_heartbeat_group_type);
2327
2328         ret = &hs->hs_group;
2329 out:
2330         if (ret == NULL)
2331                 kfree(hs);
2332         return ret;
2333 }
2334
2335 void o2hb_free_hb_set(struct config_group *group)
2336 {
2337         struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
2338         kfree(hs);
2339 }
2340
2341 /* hb callback registration and issuing */
2342
2343 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
2344 {
2345         if (type == O2HB_NUM_CB)
2346                 return ERR_PTR(-EINVAL);
2347
2348         return &o2hb_callbacks[type];
2349 }
2350
2351 void o2hb_setup_callback(struct o2hb_callback_func *hc,
2352                          enum o2hb_callback_type type,
2353                          o2hb_cb_func *func,
2354                          void *data,
2355                          int priority)
2356 {
2357         INIT_LIST_HEAD(&hc->hc_item);
2358         hc->hc_func = func;
2359         hc->hc_data = data;
2360         hc->hc_priority = priority;
2361         hc->hc_type = type;
2362         hc->hc_magic = O2HB_CB_MAGIC;
2363 }
2364 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
2365
2366 /*
2367  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2368  * In global heartbeat mode, region_uuid passed is NULL.
2369  *
2370  * In local, we only pin the matching region. In global we pin all the active
2371  * regions.
2372  */
2373 static int o2hb_region_pin(const char *region_uuid)
2374 {
2375         int ret = 0, found = 0;
2376         struct o2hb_region *reg;
2377         char *uuid;
2378
2379         assert_spin_locked(&o2hb_live_lock);
2380
2381         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2382                 if (reg->hr_item_dropped)
2383                         continue;
2384
2385                 uuid = config_item_name(&reg->hr_item);
2386
2387                 /* local heartbeat */
2388                 if (region_uuid) {
2389                         if (strcmp(region_uuid, uuid))
2390                                 continue;
2391                         found = 1;
2392                 }
2393
2394                 if (reg->hr_item_pinned || reg->hr_item_dropped)
2395                         goto skip_pin;
2396
2397                 /* Ignore ENOENT only for local hb (userdlm domain) */
2398                 ret = o2nm_depend_item(&reg->hr_item);
2399                 if (!ret) {
2400                         mlog(ML_CLUSTER, "Pin region %s\n", uuid);
2401                         reg->hr_item_pinned = 1;
2402                 } else {
2403                         if (ret == -ENOENT && found)
2404                                 ret = 0;
2405                         else {
2406                                 mlog(ML_ERROR, "Pin region %s fails with %d\n",
2407                                      uuid, ret);
2408                                 break;
2409                         }
2410                 }
2411 skip_pin:
2412                 if (found)
2413                         break;
2414         }
2415
2416         return ret;
2417 }
2418
2419 /*
2420  * In local heartbeat mode, region_uuid passed matches the dlm domain name.
2421  * In global heartbeat mode, region_uuid passed is NULL.
2422  *
2423  * In local, we only unpin the matching region. In global we unpin all the
2424  * active regions.
2425  */
2426 static void o2hb_region_unpin(const char *region_uuid)
2427 {
2428         struct o2hb_region *reg;
2429         char *uuid;
2430         int found = 0;
2431
2432         assert_spin_locked(&o2hb_live_lock);
2433
2434         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2435                 if (reg->hr_item_dropped)
2436                         continue;
2437
2438                 uuid = config_item_name(&reg->hr_item);
2439                 if (region_uuid) {
2440                         if (strcmp(region_uuid, uuid))
2441                                 continue;
2442                         found = 1;
2443                 }
2444
2445                 if (reg->hr_item_pinned) {
2446                         mlog(ML_CLUSTER, "Unpin region %s\n", uuid);
2447                         o2nm_undepend_item(&reg->hr_item);
2448                         reg->hr_item_pinned = 0;
2449                 }
2450                 if (found)
2451                         break;
2452         }
2453 }
2454
2455 static int o2hb_region_inc_user(const char *region_uuid)
2456 {
2457         int ret = 0;
2458
2459         spin_lock(&o2hb_live_lock);
2460
2461         /* local heartbeat */
2462         if (!o2hb_global_heartbeat_active()) {
2463             ret = o2hb_region_pin(region_uuid);
2464             goto unlock;
2465         }
2466
2467         /*
2468          * if global heartbeat active and this is the first dependent user,
2469          * pin all regions if quorum region count <= CUT_OFF
2470          */
2471         o2hb_dependent_users++;
2472         if (o2hb_dependent_users > 1)
2473                 goto unlock;
2474
2475         if (bitmap_weight(o2hb_quorum_region_bitmap,
2476                            O2NM_MAX_REGIONS) <= O2HB_PIN_CUT_OFF)
2477                 ret = o2hb_region_pin(NULL);
2478
2479 unlock:
2480         spin_unlock(&o2hb_live_lock);
2481         return ret;
2482 }
2483
2484 void o2hb_region_dec_user(const char *region_uuid)
2485 {
2486         spin_lock(&o2hb_live_lock);
2487
2488         /* local heartbeat */
2489         if (!o2hb_global_heartbeat_active()) {
2490             o2hb_region_unpin(region_uuid);
2491             goto unlock;
2492         }
2493
2494         /*
2495          * if global heartbeat active and there are no dependent users,
2496          * unpin all quorum regions
2497          */
2498         o2hb_dependent_users--;
2499         if (!o2hb_dependent_users)
2500                 o2hb_region_unpin(NULL);
2501
2502 unlock:
2503         spin_unlock(&o2hb_live_lock);
2504 }
2505
2506 int o2hb_register_callback(const char *region_uuid,
2507                            struct o2hb_callback_func *hc)
2508 {
2509         struct o2hb_callback_func *f;
2510         struct o2hb_callback *hbcall;
2511         int ret;
2512
2513         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2514         BUG_ON(!list_empty(&hc->hc_item));
2515
2516         hbcall = hbcall_from_type(hc->hc_type);
2517         if (IS_ERR(hbcall)) {
2518                 ret = PTR_ERR(hbcall);
2519                 goto out;
2520         }
2521
2522         if (region_uuid) {
2523                 ret = o2hb_region_inc_user(region_uuid);
2524                 if (ret) {
2525                         mlog_errno(ret);
2526                         goto out;
2527                 }
2528         }
2529
2530         down_write(&o2hb_callback_sem);
2531
2532         list_for_each_entry(f, &hbcall->list, hc_item) {
2533                 if (hc->hc_priority < f->hc_priority) {
2534                         list_add_tail(&hc->hc_item, &f->hc_item);
2535                         break;
2536                 }
2537         }
2538         if (list_empty(&hc->hc_item))
2539                 list_add_tail(&hc->hc_item, &hbcall->list);
2540
2541         up_write(&o2hb_callback_sem);
2542         ret = 0;
2543 out:
2544         mlog(ML_CLUSTER, "returning %d on behalf of %p for funcs %p\n",
2545              ret, __builtin_return_address(0), hc);
2546         return ret;
2547 }
2548 EXPORT_SYMBOL_GPL(o2hb_register_callback);
2549
2550 void o2hb_unregister_callback(const char *region_uuid,
2551                               struct o2hb_callback_func *hc)
2552 {
2553         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2554
2555         mlog(ML_CLUSTER, "on behalf of %p for funcs %p\n",
2556              __builtin_return_address(0), hc);
2557
2558         /* XXX Can this happen _with_ a region reference? */
2559         if (list_empty(&hc->hc_item))
2560                 return;
2561
2562         if (region_uuid)
2563                 o2hb_region_dec_user(region_uuid);
2564
2565         down_write(&o2hb_callback_sem);
2566
2567         list_del_init(&hc->hc_item);
2568
2569         up_write(&o2hb_callback_sem);
2570 }
2571 EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
2572
2573 int o2hb_check_node_heartbeating(u8 node_num)
2574 {
2575         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2576
2577         o2hb_fill_node_map(testing_map, sizeof(testing_map));
2578         if (!test_bit(node_num, testing_map)) {
2579                 mlog(ML_HEARTBEAT,
2580                      "node (%u) does not have heartbeating enabled.\n",
2581                      node_num);
2582                 return 0;
2583         }
2584
2585         return 1;
2586 }
2587 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating);
2588
2589 int o2hb_check_node_heartbeating_from_callback(u8 node_num)
2590 {
2591         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2592
2593         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2594         if (!test_bit(node_num, testing_map)) {
2595                 mlog(ML_HEARTBEAT,
2596                      "node (%u) does not have heartbeating enabled.\n",
2597                      node_num);
2598                 return 0;
2599         }
2600
2601         return 1;
2602 }
2603 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_from_callback);
2604
2605 /* Makes sure our local node is configured with a node number, and is
2606  * heartbeating. */
2607 int o2hb_check_local_node_heartbeating(void)
2608 {
2609         u8 node_num;
2610
2611         /* if this node was set then we have networking */
2612         node_num = o2nm_this_node();
2613         if (node_num == O2NM_MAX_NODES) {
2614                 mlog(ML_HEARTBEAT, "this node has not been configured.\n");
2615                 return 0;
2616         }
2617
2618         return o2hb_check_node_heartbeating(node_num);
2619 }
2620 EXPORT_SYMBOL_GPL(o2hb_check_local_node_heartbeating);
2621
2622 /*
2623  * this is just a hack until we get the plumbing which flips file systems
2624  * read only and drops the hb ref instead of killing the node dead.
2625  */
2626 void o2hb_stop_all_regions(void)
2627 {
2628         struct o2hb_region *reg;
2629
2630         mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");
2631
2632         spin_lock(&o2hb_live_lock);
2633
2634         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
2635                 reg->hr_unclean_stop = 1;
2636
2637         spin_unlock(&o2hb_live_lock);
2638 }
2639 EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
2640
2641 int o2hb_get_all_regions(char *region_uuids, u8 max_regions)
2642 {
2643         struct o2hb_region *reg;
2644         int numregs = 0;
2645         char *p;
2646
2647         spin_lock(&o2hb_live_lock);
2648
2649         p = region_uuids;
2650         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2651                 if (reg->hr_item_dropped)
2652                         continue;
2653
2654                 mlog(0, "Region: %s\n", config_item_name(&reg->hr_item));
2655                 if (numregs < max_regions) {
2656                         memcpy(p, config_item_name(&reg->hr_item),
2657                                O2HB_MAX_REGION_NAME_LEN);
2658                         p += O2HB_MAX_REGION_NAME_LEN;
2659                 }
2660                 numregs++;
2661         }
2662
2663         spin_unlock(&o2hb_live_lock);
2664
2665         return numregs;
2666 }
2667 EXPORT_SYMBOL_GPL(o2hb_get_all_regions);
2668
2669 int o2hb_global_heartbeat_active(void)
2670 {
2671         return (o2hb_heartbeat_mode == O2HB_HEARTBEAT_GLOBAL);
2672 }
2673 EXPORT_SYMBOL(o2hb_global_heartbeat_active);