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
  39 #include "heartbeat.h"
  40 #include "tcp.h"
  41 #include "nodemanager.h"
  42 #include "quorum.h"
  43
  44 #include "masklog.h"
  45
  46
  47 /*
  48  * The first heartbeat pass had one global thread that would serialize all hb
  49  * callback calls.  This global serializing sem should only be removed once
  50  * we've made sure that all callees can deal with being called concurrently
  51  * from multiple hb region threads.
  52  */
  53 static DECLARE_RWSEM(o2hb_callback_sem);
  54
  55 /*
  56  * multiple hb threads are watching multiple regions.  A node is live
  57  * whenever any of the threads sees activity from the node in its region.
  58  */
  59 static DEFINE_SPINLOCK(o2hb_live_lock);
  60 static struct list_head o2hb_live_slots[O2NM_MAX_NODES];
  61 static unsigned long o2hb_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
  62 static LIST_HEAD(o2hb_node_events);
  63 static DECLARE_WAIT_QUEUE_HEAD(o2hb_steady_queue);
  64
  65 /*
  66  * In global heartbeat, we maintain a series of region bitmaps.
  67  *      - o2hb_region_bitmap allows us to limit the region number to max region.
  68  *      - o2hb_live_region_bitmap tracks live regions (seen steady iterations).
  69  *      - o2hb_quorum_region_bitmap tracks live regions that have seen all nodes
  70  *              heartbeat on it.
  71  *      - o2hb_failed_region_bitmap tracks the regions that have seen io timeouts.
  72  */
  73 static unsigned long o2hb_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  74 static unsigned long o2hb_live_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  75 static unsigned long o2hb_quorum_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  76 static unsigned long o2hb_failed_region_bitmap[BITS_TO_LONGS(O2NM_MAX_REGIONS)];
  77
  78 #define O2HB_DB_TYPE_LIVENODES          0
  79 #define O2HB_DB_TYPE_LIVEREGIONS        1
  80 #define O2HB_DB_TYPE_QUORUMREGIONS      2
  81 #define O2HB_DB_TYPE_FAILEDREGIONS      3
  82 #define O2HB_DB_TYPE_REGION_LIVENODES   4
  83 #define O2HB_DB_TYPE_REGION_NUMBER      5
  84 #define O2HB_DB_TYPE_REGION_ELAPSED_TIME        6
  85 struct o2hb_debug_buf {
  86         int db_type;
  87         int db_size;
  88         int db_len;
  89         void *db_data;
  90 };
  91
  92 static struct o2hb_debug_buf *o2hb_db_livenodes;
  93 static struct o2hb_debug_buf *o2hb_db_liveregions;
  94 static struct o2hb_debug_buf *o2hb_db_quorumregions;
  95 static struct o2hb_debug_buf *o2hb_db_failedregions;
  96
  97 #define O2HB_DEBUG_DIR                  "o2hb"
  98 #define O2HB_DEBUG_LIVENODES            "livenodes"
  99 #define O2HB_DEBUG_LIVEREGIONS          "live_regions"
 100 #define O2HB_DEBUG_QUORUMREGIONS        "quorum_regions"
 101 #define O2HB_DEBUG_FAILEDREGIONS        "failed_regions"
 102 #define O2HB_DEBUG_REGION_NUMBER        "num"
 103 #define O2HB_DEBUG_REGION_ELAPSED_TIME  "elapsed_time_in_ms"
 104
 105 static struct dentry *o2hb_debug_dir;
 106 static struct dentry *o2hb_debug_livenodes;
 107 static struct dentry *o2hb_debug_liveregions;
 108 static struct dentry *o2hb_debug_quorumregions;
 109 static struct dentry *o2hb_debug_failedregions;
 110
 111 static LIST_HEAD(o2hb_all_regions);
 112
 113 static struct o2hb_callback {
 114         struct list_head list;
 115 } o2hb_callbacks[O2HB_NUM_CB];
 116
 117 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type);
 118
 119 #define O2HB_DEFAULT_BLOCK_BITS       9
 120
 121 enum o2hb_heartbeat_modes {
 122         O2HB_HEARTBEAT_LOCAL            = 0,
 123         O2HB_HEARTBEAT_GLOBAL,
 124         O2HB_HEARTBEAT_NUM_MODES,
 125 };
 126
 127 char *o2hb_heartbeat_mode_desc[O2HB_HEARTBEAT_NUM_MODES] = {
 128                 "local",        /* O2HB_HEARTBEAT_LOCAL */
 129                 "global",       /* O2HB_HEARTBEAT_GLOBAL */
 130 };
 131
 132 unsigned int o2hb_dead_threshold = O2HB_DEFAULT_DEAD_THRESHOLD;
 133 unsigned int o2hb_heartbeat_mode = O2HB_HEARTBEAT_LOCAL;
 134
 135 /* Only sets a new threshold if there are no active regions.
 136  *
 137  * No locking or otherwise interesting code is required for reading
 138  * o2hb_dead_threshold as it can't change once regions are active and
 139  * it's not interesting to anyone until then anyway. */
 140 static void o2hb_dead_threshold_set(unsigned int threshold)
 141 {
 142         if (threshold > O2HB_MIN_DEAD_THRESHOLD) {
 143                 spin_lock(&o2hb_live_lock);
 144                 if (list_empty(&o2hb_all_regions))
 145                         o2hb_dead_threshold = threshold;
 146                 spin_unlock(&o2hb_live_lock);
 147         }
 148 }
 149
 150 static int o2hb_global_hearbeat_mode_set(unsigned int hb_mode)
 151 {
 152         int ret = -1;
 153
 154         if (hb_mode < O2HB_HEARTBEAT_NUM_MODES) {
 155                 spin_lock(&o2hb_live_lock);
 156                 if (list_empty(&o2hb_all_regions)) {
 157                         o2hb_heartbeat_mode = hb_mode;
 158                         ret = 0;
 159                 }
 160                 spin_unlock(&o2hb_live_lock);
 161         }
 162
 163         return ret;
 164 }
 165
 166 struct o2hb_node_event {
 167         struct list_head        hn_item;
 168         enum o2hb_callback_type hn_event_type;
 169         struct o2nm_node        *hn_node;
 170         int                     hn_node_num;
 171 };
 172
 173 struct o2hb_disk_slot {
 174         struct o2hb_disk_heartbeat_block *ds_raw_block;
 175         u8                      ds_node_num;
 176         u64                     ds_last_time;
 177         u64                     ds_last_generation;
 178         u16                     ds_equal_samples;
 179         u16                     ds_changed_samples;
 180         struct list_head        ds_live_item;
 181 };
 182
 183 /* each thread owns a region.. when we're asked to tear down the region
 184  * we ask the thread to stop, who cleans up the region */
 185 struct o2hb_region {
 186         struct config_item      hr_item;
 187
 188         struct list_head        hr_all_item;
 189         unsigned                hr_unclean_stop:1;
 190
 191         /* protected by the hr_callback_sem */
 192         struct task_struct      *hr_task;
 193
 194         unsigned int            hr_blocks;
 195         unsigned long long      hr_start_block;
 196
 197         unsigned int            hr_block_bits;
 198         unsigned int            hr_block_bytes;
 199
 200         unsigned int            hr_slots_per_page;
 201         unsigned int            hr_num_pages;
 202
 203         struct page             **hr_slot_data;
 204         struct block_device     *hr_bdev;
 205         struct o2hb_disk_slot   *hr_slots;
 206
 207         /* live node map of this region */
 208         unsigned long           hr_live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 209         unsigned int            hr_region_num;
 210
 211         struct dentry           *hr_debug_dir;
 212         struct dentry           *hr_debug_livenodes;
 213         struct dentry           *hr_debug_regnum;
 214         struct dentry           *hr_debug_elapsed_time;
 215         struct o2hb_debug_buf   *hr_db_livenodes;
 216         struct o2hb_debug_buf   *hr_db_regnum;
 217         struct o2hb_debug_buf   *hr_db_elapsed_time;
 218
 219         /* let the person setting up hb wait for it to return until it
 220          * has reached a 'steady' state.  This will be fixed when we have
 221          * a more complete api that doesn't lead to this sort of fragility. */
 222         atomic_t                hr_steady_iterations;
 223
 224         char                    hr_dev_name[BDEVNAME_SIZE];
 225
 226         unsigned int            hr_timeout_ms;
 227
 228         /* randomized as the region goes up and down so that a node
 229          * recognizes a node going up and down in one iteration */
 230         u64                     hr_generation;
 231
 232         struct delayed_work     hr_write_timeout_work;
 233         unsigned long           hr_last_timeout_start;
 234
 235         /* Used during o2hb_check_slot to hold a copy of the block
 236          * being checked because we temporarily have to zero out the
 237          * crc field. */
 238         struct o2hb_disk_heartbeat_block *hr_tmp_block;
 239 };
 240
 241 struct o2hb_bio_wait_ctxt {
 242         atomic_t          wc_num_reqs;
 243         struct completion wc_io_complete;
 244         int               wc_error;
 245 };
 246
 247 static int o2hb_pop_count(void *map, int count)
 248 {
 249         int i = -1, pop = 0;
 250
 251         while ((i = find_next_bit(map, count, i + 1)) < count)
 252                 pop++;
 253         return pop;
 254 }
 255
 256 static void o2hb_write_timeout(struct work_struct *work)
 257 {
 258         int failed, quorum;
 259         unsigned long flags;
 260         struct o2hb_region *reg =
 261                 container_of(work, struct o2hb_region,
 262                              hr_write_timeout_work.work);
 263
 264         mlog(ML_ERROR, "Heartbeat write timeout to device %s after %u "
 265              "milliseconds\n", reg->hr_dev_name,
 266              jiffies_to_msecs(jiffies - reg->hr_last_timeout_start));
 267
 268         if (o2hb_global_heartbeat_active()) {
 269                 spin_lock_irqsave(&o2hb_live_lock, flags);
 270                 if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 271                         set_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 272                 failed = o2hb_pop_count(&o2hb_failed_region_bitmap,
 273                                         O2NM_MAX_REGIONS);
 274                 quorum = o2hb_pop_count(&o2hb_quorum_region_bitmap,
 275                                         O2NM_MAX_REGIONS);
 276                 spin_unlock_irqrestore(&o2hb_live_lock, flags);
 277
 278                 mlog(ML_HEARTBEAT, "Number of regions %d, failed regions %d\n",
 279                      quorum, failed);
 280
 281                 /*
 282                  * Fence if the number of failed regions >= half the number
 283                  * of  quorum regions
 284                  */
 285                 if ((failed << 1) < quorum)
 286                         return;
 287         }
 288
 289         o2quo_disk_timeout();
 290 }
 291
 292 static void o2hb_arm_write_timeout(struct o2hb_region *reg)
 293 {
 294         mlog(ML_HEARTBEAT, "Queue write timeout for %u ms\n",
 295              O2HB_MAX_WRITE_TIMEOUT_MS);
 296
 297         if (o2hb_global_heartbeat_active()) {
 298                 spin_lock(&o2hb_live_lock);
 299                 clear_bit(reg->hr_region_num, o2hb_failed_region_bitmap);
 300                 spin_unlock(&o2hb_live_lock);
 301         }
 302         cancel_delayed_work(&reg->hr_write_timeout_work);
 303         reg->hr_last_timeout_start = jiffies;
 304         schedule_delayed_work(&reg->hr_write_timeout_work,
 305                               msecs_to_jiffies(O2HB_MAX_WRITE_TIMEOUT_MS));
 306 }
 307
 308 static void o2hb_disarm_write_timeout(struct o2hb_region *reg)
 309 {
 310         cancel_delayed_work(&reg->hr_write_timeout_work);
 311         flush_scheduled_work();
 312 }
 313
 314 static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)
 315 {
 316         atomic_set(&wc->wc_num_reqs, 1);
 317         init_completion(&wc->wc_io_complete);
 318         wc->wc_error = 0;
 319 }
 320
 321 /* Used in error paths too */
 322 static inline void o2hb_bio_wait_dec(struct o2hb_bio_wait_ctxt *wc,
 323                                      unsigned int num)
 324 {
 325         /* sadly atomic_sub_and_test() isn't available on all platforms.  The
 326          * good news is that the fast path only completes one at a time */
 327         while(num--) {
 328                 if (atomic_dec_and_test(&wc->wc_num_reqs)) {
 329                         BUG_ON(num > 0);
 330                         complete(&wc->wc_io_complete);
 331                 }
 332         }
 333 }
 334
 335 static void o2hb_wait_on_io(struct o2hb_region *reg,
 336                             struct o2hb_bio_wait_ctxt *wc)
 337 {
 338         struct address_space *mapping = reg->hr_bdev->bd_inode->i_mapping;
 339
 340         blk_run_address_space(mapping);
 341         o2hb_bio_wait_dec(wc, 1);
 342
 343         wait_for_completion(&wc->wc_io_complete);
 344 }
 345
 346 static void o2hb_bio_end_io(struct bio *bio,
 347                            int error)
 348 {
 349         struct o2hb_bio_wait_ctxt *wc = bio->bi_private;
 350
 351         if (error) {
 352                 mlog(ML_ERROR, "IO Error %d\n", error);
 353                 wc->wc_error = error;
 354         }
 355
 356         o2hb_bio_wait_dec(wc, 1);
 357         bio_put(bio);
 358 }
 359
 360 /* Setup a Bio to cover I/O against num_slots slots starting at
 361  * start_slot. */
 362 static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
 363                                       struct o2hb_bio_wait_ctxt *wc,
 364                                       unsigned int *current_slot,
 365                                       unsigned int max_slots)
 366 {
 367         int len, current_page;
 368         unsigned int vec_len, vec_start;
 369         unsigned int bits = reg->hr_block_bits;
 370         unsigned int spp = reg->hr_slots_per_page;
 371         unsigned int cs = *current_slot;
 372         struct bio *bio;
 373         struct page *page;
 374
 375         /* Testing has shown this allocation to take long enough under
 376          * GFP_KERNEL that the local node can get fenced. It would be
 377          * nicest if we could pre-allocate these bios and avoid this
 378          * all together. */
 379         bio = bio_alloc(GFP_ATOMIC, 16);
 380         if (!bio) {
 381                 mlog(ML_ERROR, "Could not alloc slots BIO!\n");
 382                 bio = ERR_PTR(-ENOMEM);
 383                 goto bail;
 384         }
 385
 386         /* Must put everything in 512 byte sectors for the bio... */
 387         bio->bi_sector = (reg->hr_start_block + cs) << (bits - 9);
 388         bio->bi_bdev = reg->hr_bdev;
 389         bio->bi_private = wc;
 390         bio->bi_end_io = o2hb_bio_end_io;
 391
 392         vec_start = (cs << bits) % PAGE_CACHE_SIZE;
 393         while(cs < max_slots) {
 394                 current_page = cs / spp;
 395                 page = reg->hr_slot_data[current_page];
 396
 397                 vec_len = min(PAGE_CACHE_SIZE - vec_start,
 398                               (max_slots-cs) * (PAGE_CACHE_SIZE/spp) );
 399
 400                 mlog(ML_HB_BIO, "page %d, vec_len = %u, vec_start = %u\n",
 401                      current_page, vec_len, vec_start);
 402
 403                 len = bio_add_page(bio, page, vec_len, vec_start);
 404                 if (len != vec_len) break;
 405
 406                 cs += vec_len / (PAGE_CACHE_SIZE/spp);
 407                 vec_start = 0;
 408         }
 409
 410 bail:
 411         *current_slot = cs;
 412         return bio;
 413 }
 414
 415 static int o2hb_read_slots(struct o2hb_region *reg,
 416                            unsigned int max_slots)
 417 {
 418         unsigned int current_slot=0;
 419         int status;
 420         struct o2hb_bio_wait_ctxt wc;
 421         struct bio *bio;
 422
 423         o2hb_bio_wait_init(&wc);
 424
 425         while(current_slot < max_slots) {
 426                 bio = o2hb_setup_one_bio(reg, &wc, &current_slot, max_slots);
 427                 if (IS_ERR(bio)) {
 428                         status = PTR_ERR(bio);
 429                         mlog_errno(status);
 430                         goto bail_and_wait;
 431                 }
 432
 433                 atomic_inc(&wc.wc_num_reqs);
 434                 submit_bio(READ, bio);
 435         }
 436
 437         status = 0;
 438
 439 bail_and_wait:
 440         o2hb_wait_on_io(reg, &wc);
 441         if (wc.wc_error && !status)
 442                 status = wc.wc_error;
 443
 444         return status;
 445 }
 446
 447 static int o2hb_issue_node_write(struct o2hb_region *reg,
 448                                  struct o2hb_bio_wait_ctxt *write_wc)
 449 {
 450         int status;
 451         unsigned int slot;
 452         struct bio *bio;
 453
 454         o2hb_bio_wait_init(write_wc);
 455
 456         slot = o2nm_this_node();
 457
 458         bio = o2hb_setup_one_bio(reg, write_wc, &slot, slot+1);
 459         if (IS_ERR(bio)) {
 460                 status = PTR_ERR(bio);
 461                 mlog_errno(status);
 462                 goto bail;
 463         }
 464
 465         atomic_inc(&write_wc->wc_num_reqs);
 466         submit_bio(WRITE, bio);
 467
 468         status = 0;
 469 bail:
 470         return status;
 471 }
 472
 473 static u32 o2hb_compute_block_crc_le(struct o2hb_region *reg,
 474                                      struct o2hb_disk_heartbeat_block *hb_block)
 475 {
 476         __le32 old_cksum;
 477         u32 ret;
 478
 479         /* We want to compute the block crc with a 0 value in the
 480          * hb_cksum field. Save it off here and replace after the
 481          * crc. */
 482         old_cksum = hb_block->hb_cksum;
 483         hb_block->hb_cksum = 0;
 484
 485         ret = crc32_le(0, (unsigned char *) hb_block, reg->hr_block_bytes);
 486
 487         hb_block->hb_cksum = old_cksum;
 488
 489         return ret;
 490 }
 491
 492 static void o2hb_dump_slot(struct o2hb_disk_heartbeat_block *hb_block)
 493 {
 494         mlog(ML_ERROR, "Dump slot information: seq = 0x%llx, node = %u, "
 495              "cksum = 0x%x, generation 0x%llx\n",
 496              (long long)le64_to_cpu(hb_block->hb_seq),
 497              hb_block->hb_node, le32_to_cpu(hb_block->hb_cksum),
 498              (long long)le64_to_cpu(hb_block->hb_generation));
 499 }
 500
 501 static int o2hb_verify_crc(struct o2hb_region *reg,
 502                            struct o2hb_disk_heartbeat_block *hb_block)
 503 {
 504         u32 read, computed;
 505
 506         read = le32_to_cpu(hb_block->hb_cksum);
 507         computed = o2hb_compute_block_crc_le(reg, hb_block);
 508
 509         return read == computed;
 510 }
 511
 512 /* We want to make sure that nobody is heartbeating on top of us --
 513  * this will help detect an invalid configuration. */
 514 static int o2hb_check_last_timestamp(struct o2hb_region *reg)
 515 {
 516         int node_num, ret;
 517         struct o2hb_disk_slot *slot;
 518         struct o2hb_disk_heartbeat_block *hb_block;
 519
 520         node_num = o2nm_this_node();
 521
 522         ret = 1;
 523         slot = &reg->hr_slots[node_num];
 524         /* Don't check on our 1st timestamp */
 525         if (slot->ds_last_time) {
 526                 hb_block = slot->ds_raw_block;
 527
 528                 if (le64_to_cpu(hb_block->hb_seq) != slot->ds_last_time)
 529                         ret = 0;
 530         }
 531
 532         return ret;
 533 }
 534
 535 static inline void o2hb_prepare_block(struct o2hb_region *reg,
 536                                       u64 generation)
 537 {
 538         int node_num;
 539         u64 cputime;
 540         struct o2hb_disk_slot *slot;
 541         struct o2hb_disk_heartbeat_block *hb_block;
 542
 543         node_num = o2nm_this_node();
 544         slot = &reg->hr_slots[node_num];
 545
 546         hb_block = (struct o2hb_disk_heartbeat_block *)slot->ds_raw_block;
 547         memset(hb_block, 0, reg->hr_block_bytes);
 548         /* TODO: time stuff */
 549         cputime = CURRENT_TIME.tv_sec;
 550         if (!cputime)
 551                 cputime = 1;
 552
 553         hb_block->hb_seq = cpu_to_le64(cputime);
 554         hb_block->hb_node = node_num;
 555         hb_block->hb_generation = cpu_to_le64(generation);
 556         hb_block->hb_dead_ms = cpu_to_le32(o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS);
 557
 558         /* This step must always happen last! */
 559         hb_block->hb_cksum = cpu_to_le32(o2hb_compute_block_crc_le(reg,
 560                                                                    hb_block));
 561
 562         mlog(ML_HB_BIO, "our node generation = 0x%llx, cksum = 0x%x\n",
 563              (long long)generation,
 564              le32_to_cpu(hb_block->hb_cksum));
 565 }
 566
 567 static void o2hb_fire_callbacks(struct o2hb_callback *hbcall,
 568                                 struct o2nm_node *node,
 569                                 int idx)
 570 {
 571         struct list_head *iter;
 572         struct o2hb_callback_func *f;
 573
 574         list_for_each(iter, &hbcall->list) {
 575                 f = list_entry(iter, struct o2hb_callback_func, hc_item);
 576                 mlog(ML_HEARTBEAT, "calling funcs %p\n", f);
 577                 (f->hc_func)(node, idx, f->hc_data);
 578         }
 579 }
 580
 581 /* Will run the list in order until we process the passed event */
 582 static void o2hb_run_event_list(struct o2hb_node_event *queued_event)
 583 {
 584         int empty;
 585         struct o2hb_callback *hbcall;
 586         struct o2hb_node_event *event;
 587
 588         spin_lock(&o2hb_live_lock);
 589         empty = list_empty(&queued_event->hn_item);
 590         spin_unlock(&o2hb_live_lock);
 591         if (empty)
 592                 return;
 593
 594         /* Holding callback sem assures we don't alter the callback
 595          * lists when doing this, and serializes ourselves with other
 596          * processes wanting callbacks. */
 597         down_write(&o2hb_callback_sem);
 598
 599         spin_lock(&o2hb_live_lock);
 600         while (!list_empty(&o2hb_node_events)
 601                && !list_empty(&queued_event->hn_item)) {
 602                 event = list_entry(o2hb_node_events.next,
 603                                    struct o2hb_node_event,
 604                                    hn_item);
 605                 list_del_init(&event->hn_item);
 606                 spin_unlock(&o2hb_live_lock);
 607
 608                 mlog(ML_HEARTBEAT, "Node %s event for %d\n",
 609                      event->hn_event_type == O2HB_NODE_UP_CB ? "UP" : "DOWN",
 610                      event->hn_node_num);
 611
 612                 hbcall = hbcall_from_type(event->hn_event_type);
 613
 614                 /* We should *never* have gotten on to the list with a
 615                  * bad type... This isn't something that we should try
 616                  * to recover from. */
 617                 BUG_ON(IS_ERR(hbcall));
 618
 619                 o2hb_fire_callbacks(hbcall, event->hn_node, event->hn_node_num);
 620
 621                 spin_lock(&o2hb_live_lock);
 622         }
 623         spin_unlock(&o2hb_live_lock);
 624
 625         up_write(&o2hb_callback_sem);
 626 }
 627
 628 static void o2hb_queue_node_event(struct o2hb_node_event *event,
 629                                   enum o2hb_callback_type type,
 630                                   struct o2nm_node *node,
 631                                   int node_num)
 632 {
 633         assert_spin_locked(&o2hb_live_lock);
 634
 635         BUG_ON((!node) && (type != O2HB_NODE_DOWN_CB));
 636
 637         event->hn_event_type = type;
 638         event->hn_node = node;
 639         event->hn_node_num = node_num;
 640
 641         mlog(ML_HEARTBEAT, "Queue node %s event for node %d\n",
 642              type == O2HB_NODE_UP_CB ? "UP" : "DOWN", node_num);
 643
 644         list_add_tail(&event->hn_item, &o2hb_node_events);
 645 }
 646
 647 static void o2hb_shutdown_slot(struct o2hb_disk_slot *slot)
 648 {
 649         struct o2hb_node_event event =
 650                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 651         struct o2nm_node *node;
 652
 653         node = o2nm_get_node_by_num(slot->ds_node_num);
 654         if (!node)
 655                 return;
 656
 657         spin_lock(&o2hb_live_lock);
 658         if (!list_empty(&slot->ds_live_item)) {
 659                 mlog(ML_HEARTBEAT, "Shutdown, node %d leaves region\n",
 660                      slot->ds_node_num);
 661
 662                 list_del_init(&slot->ds_live_item);
 663
 664                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 665                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 666
 667                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB, node,
 668                                               slot->ds_node_num);
 669                 }
 670         }
 671         spin_unlock(&o2hb_live_lock);
 672
 673         o2hb_run_event_list(&event);
 674
 675         o2nm_node_put(node);
 676 }
 677
 678 static void o2hb_set_quorum_device(struct o2hb_region *reg,
 679                                    struct o2hb_disk_slot *slot)
 680 {
 681         assert_spin_locked(&o2hb_live_lock);
 682
 683         if (!o2hb_global_heartbeat_active())
 684                 return;
 685
 686         if (test_bit(reg->hr_region_num, o2hb_quorum_region_bitmap))
 687                 return;
 688
 689         /*
 690          * A region can be added to the quorum only when it sees all
 691          * live nodes heartbeat on it. In other words, the region has been
 692          * added to all nodes.
 693          */
 694         if (memcmp(reg->hr_live_node_bitmap, o2hb_live_node_bitmap,
 695                    sizeof(o2hb_live_node_bitmap)))
 696                 return;
 697
 698         if (slot->ds_changed_samples < O2HB_LIVE_THRESHOLD)
 699                 return;
 700
 701         printk(KERN_NOTICE "o2hb: Region %s is now a quorum device\n",
 702                config_item_name(&reg->hr_item));
 703
 704         set_bit(reg->hr_region_num, o2hb_quorum_region_bitmap);
 705 }
 706
 707 static int o2hb_check_slot(struct o2hb_region *reg,
 708                            struct o2hb_disk_slot *slot)
 709 {
 710         int changed = 0, gen_changed = 0;
 711         struct o2hb_node_event event =
 712                 { .hn_item = LIST_HEAD_INIT(event.hn_item), };
 713         struct o2nm_node *node;
 714         struct o2hb_disk_heartbeat_block *hb_block = reg->hr_tmp_block;
 715         u64 cputime;
 716         unsigned int dead_ms = o2hb_dead_threshold * O2HB_REGION_TIMEOUT_MS;
 717         unsigned int slot_dead_ms;
 718         int tmp;
 719
 720         memcpy(hb_block, slot->ds_raw_block, reg->hr_block_bytes);
 721
 722         /*
 723          * If a node is no longer configured but is still in the livemap, we
 724          * may need to clear that bit from the livemap.
 725          */
 726         node = o2nm_get_node_by_num(slot->ds_node_num);
 727         if (!node) {
 728                 spin_lock(&o2hb_live_lock);
 729                 tmp = test_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 730                 spin_unlock(&o2hb_live_lock);
 731                 if (!tmp)
 732                         return 0;
 733         }
 734
 735         if (!o2hb_verify_crc(reg, hb_block)) {
 736                 /* all paths from here will drop o2hb_live_lock for
 737                  * us. */
 738                 spin_lock(&o2hb_live_lock);
 739
 740                 /* Don't print an error on the console in this case -
 741                  * a freshly formatted heartbeat area will not have a
 742                  * crc set on it. */
 743                 if (list_empty(&slot->ds_live_item))
 744                         goto out;
 745
 746                 /* The node is live but pushed out a bad crc. We
 747                  * consider it a transient miss but don't populate any
 748                  * other values as they may be junk. */
 749                 mlog(ML_ERROR, "Node %d has written a bad crc to %s\n",
 750                      slot->ds_node_num, reg->hr_dev_name);
 751                 o2hb_dump_slot(hb_block);
 752
 753                 slot->ds_equal_samples++;
 754                 goto fire_callbacks;
 755         }
 756
 757         /* we don't care if these wrap.. the state transitions below
 758          * clear at the right places */
 759         cputime = le64_to_cpu(hb_block->hb_seq);
 760         if (slot->ds_last_time != cputime)
 761                 slot->ds_changed_samples++;
 762         else
 763                 slot->ds_equal_samples++;
 764         slot->ds_last_time = cputime;
 765
 766         /* The node changed heartbeat generations. We assume this to
 767          * mean it dropped off but came back before we timed out. We
 768          * want to consider it down for the time being but don't want
 769          * to lose any changed_samples state we might build up to
 770          * considering it live again. */
 771         if (slot->ds_last_generation != le64_to_cpu(hb_block->hb_generation)) {
 772                 gen_changed = 1;
 773                 slot->ds_equal_samples = 0;
 774                 mlog(ML_HEARTBEAT, "Node %d changed generation (0x%llx "
 775                      "to 0x%llx)\n", slot->ds_node_num,
 776                      (long long)slot->ds_last_generation,
 777                      (long long)le64_to_cpu(hb_block->hb_generation));
 778         }
 779
 780         slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
 781
 782         mlog(ML_HEARTBEAT, "Slot %d gen 0x%llx cksum 0x%x "
 783              "seq %llu last %llu changed %u equal %u\n",
 784              slot->ds_node_num, (long long)slot->ds_last_generation,
 785              le32_to_cpu(hb_block->hb_cksum),
 786              (unsigned long long)le64_to_cpu(hb_block->hb_seq),
 787              (unsigned long long)slot->ds_last_time, slot->ds_changed_samples,
 788              slot->ds_equal_samples);
 789
 790         spin_lock(&o2hb_live_lock);
 791
 792 fire_callbacks:
 793         /* dead nodes only come to life after some number of
 794          * changes at any time during their dead time */
 795         if (list_empty(&slot->ds_live_item) &&
 796             slot->ds_changed_samples >= O2HB_LIVE_THRESHOLD) {
 797                 mlog(ML_HEARTBEAT, "Node %d (id 0x%llx) joined my region\n",
 798                      slot->ds_node_num, (long long)slot->ds_last_generation);
 799
 800                 set_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 801
 802                 /* first on the list generates a callback */
 803                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 804                         mlog(ML_HEARTBEAT, "o2hb: Add node %d to live nodes "
 805                              "bitmap\n", slot->ds_node_num);
 806                         set_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 807
 808                         o2hb_queue_node_event(&event, O2HB_NODE_UP_CB, node,
 809                                               slot->ds_node_num);
 810
 811                         changed = 1;
 812                 }
 813
 814                 list_add_tail(&slot->ds_live_item,
 815                               &o2hb_live_slots[slot->ds_node_num]);
 816
 817                 slot->ds_equal_samples = 0;
 818
 819                 /* We want to be sure that all nodes agree on the
 820                  * number of milliseconds before a node will be
 821                  * considered dead. The self-fencing timeout is
 822                  * computed from this value, and a discrepancy might
 823                  * result in heartbeat calling a node dead when it
 824                  * hasn't self-fenced yet. */
 825                 slot_dead_ms = le32_to_cpu(hb_block->hb_dead_ms);
 826                 if (slot_dead_ms && slot_dead_ms != dead_ms) {
 827                         /* TODO: Perhaps we can fail the region here. */
 828                         mlog(ML_ERROR, "Node %d on device %s has a dead count "
 829                              "of %u ms, but our count is %u ms.\n"
 830                              "Please double check your configuration values "
 831                              "for 'O2CB_HEARTBEAT_THRESHOLD'\n",
 832                              slot->ds_node_num, reg->hr_dev_name, slot_dead_ms,
 833                              dead_ms);
 834                 }
 835                 goto out;
 836         }
 837
 838         /* if the list is dead, we're done.. */
 839         if (list_empty(&slot->ds_live_item))
 840                 goto out;
 841
 842         /* live nodes only go dead after enough consequtive missed
 843          * samples..  reset the missed counter whenever we see
 844          * activity */
 845         if (slot->ds_equal_samples >= o2hb_dead_threshold || gen_changed) {
 846                 mlog(ML_HEARTBEAT, "Node %d left my region\n",
 847                      slot->ds_node_num);
 848
 849                 clear_bit(slot->ds_node_num, reg->hr_live_node_bitmap);
 850
 851                 /* last off the live_slot generates a callback */
 852                 list_del_init(&slot->ds_live_item);
 853                 if (list_empty(&o2hb_live_slots[slot->ds_node_num])) {
 854                         mlog(ML_HEARTBEAT, "o2hb: Remove node %d from live "
 855                              "nodes bitmap\n", slot->ds_node_num);
 856                         clear_bit(slot->ds_node_num, o2hb_live_node_bitmap);
 857
 858                         /* node can be null */
 859                         o2hb_queue_node_event(&event, O2HB_NODE_DOWN_CB,
 860                                               node, slot->ds_node_num);
 861
 862                         changed = 1;
 863                 }
 864
 865                 /* We don't clear this because the node is still
 866                  * actually writing new blocks. */
 867                 if (!gen_changed)
 868                         slot->ds_changed_samples = 0;
 869                 goto out;
 870         }
 871         if (slot->ds_changed_samples) {
 872                 slot->ds_changed_samples = 0;
 873                 slot->ds_equal_samples = 0;
 874         }
 875 out:
 876         o2hb_set_quorum_device(reg, slot);
 877
 878         spin_unlock(&o2hb_live_lock);
 879
 880         o2hb_run_event_list(&event);
 881
 882         if (node)
 883                 o2nm_node_put(node);
 884         return changed;
 885 }
 886
 887 /* This could be faster if we just implmented a find_last_bit, but I
 888  * don't think the circumstances warrant it. */
 889 static int o2hb_highest_node(unsigned long *nodes,
 890                              int numbits)
 891 {
 892         int highest, node;
 893
 894         highest = numbits;
 895         node = -1;
 896         while ((node = find_next_bit(nodes, numbits, node + 1)) != -1) {
 897                 if (node >= numbits)
 898                         break;
 899
 900                 highest = node;
 901         }
 902
 903         return highest;
 904 }
 905
 906 static int o2hb_do_disk_heartbeat(struct o2hb_region *reg)
 907 {
 908         int i, ret, highest_node, change = 0;
 909         unsigned long configured_nodes[BITS_TO_LONGS(O2NM_MAX_NODES)];
 910         unsigned long live_node_bitmap[BITS_TO_LONGS(O2NM_MAX_NODES)];
 911         struct o2hb_bio_wait_ctxt write_wc;
 912
 913         ret = o2nm_configured_node_map(configured_nodes,
 914                                        sizeof(configured_nodes));
 915         if (ret) {
 916                 mlog_errno(ret);
 917                 return ret;
 918         }
 919
 920         /*
 921          * If a node is not configured but is in the livemap, we still need
 922          * to read the slot so as to be able to remove it from the livemap.
 923          */
 924         o2hb_fill_node_map(live_node_bitmap, sizeof(live_node_bitmap));
 925         i = -1;
 926         while ((i = find_next_bit(live_node_bitmap,
 927                                   O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
 928                 set_bit(i, configured_nodes);
 929         }
 930
 931         highest_node = o2hb_highest_node(configured_nodes, O2NM_MAX_NODES);
 932         if (highest_node >= O2NM_MAX_NODES) {
 933                 mlog(ML_NOTICE, "ocfs2_heartbeat: no configured nodes found!\n");
 934                 return -EINVAL;
 935         }
 936
 937         /* No sense in reading the slots of nodes that don't exist
 938          * yet. Of course, if the node definitions have holes in them
 939          * then we're reading an empty slot anyway... Consider this
 940          * best-effort. */
 941         ret = o2hb_read_slots(reg, highest_node + 1);
 942         if (ret < 0) {
 943                 mlog_errno(ret);
 944                 return ret;
 945         }
 946
 947         /* With an up to date view of the slots, we can check that no
 948          * other node has been improperly configured to heartbeat in
 949          * our slot. */
 950         if (!o2hb_check_last_timestamp(reg))
 951                 mlog(ML_ERROR, "Device \"%s\": another node is heartbeating "
 952                      "in our slot!\n", reg->hr_dev_name);
 953
 954         /* fill in the proper info for our next heartbeat */
 955         o2hb_prepare_block(reg, reg->hr_generation);
 956
 957         /* And fire off the write. Note that we don't wait on this I/O
 958          * until later. */
 959         ret = o2hb_issue_node_write(reg, &write_wc);
 960         if (ret < 0) {
 961                 mlog_errno(ret);
 962                 return ret;
 963         }
 964
 965         i = -1;
 966         while((i = find_next_bit(configured_nodes, O2NM_MAX_NODES, i + 1)) < O2NM_MAX_NODES) {
 967
 968                 change |= o2hb_check_slot(reg, &reg->hr_slots[i]);
 969         }
 970
 971         /*
 972          * We have to be sure we've advertised ourselves on disk
 973          * before we can go to steady state.  This ensures that
 974          * people we find in our steady state have seen us.
 975          */
 976         o2hb_wait_on_io(reg, &write_wc);
 977         if (write_wc.wc_error) {
 978                 /* Do not re-arm the write timeout on I/O error - we
 979                  * can't be sure that the new block ever made it to
 980                  * disk */
 981                 mlog(ML_ERROR, "Write error %d on device \"%s\"\n",
 982                      write_wc.wc_error, reg->hr_dev_name);
 983                 return write_wc.wc_error;
 984         }
 985
 986         o2hb_arm_write_timeout(reg);
 987
 988         /* let the person who launched us know when things are steady */
 989         if (!change && (atomic_read(&reg->hr_steady_iterations) != 0)) {
 990                 if (atomic_dec_and_test(&reg->hr_steady_iterations))
 991                         wake_up(&o2hb_steady_queue);
 992         }
 993
 994         return 0;
 995 }
 996
 997 /* Subtract b from a, storing the result in a. a *must* have a larger
 998  * value than b. */
 999 static void o2hb_tv_subtract(struct timeval *a,
1000                              struct timeval *b)
1001 {
1002         /* just return 0 when a is after b */
1003         if (a->tv_sec < b->tv_sec ||
1004             (a->tv_sec == b->tv_sec && a->tv_usec < b->tv_usec)) {
1005                 a->tv_sec = 0;
1006                 a->tv_usec = 0;
1007                 return;
1008         }
1009
1010         a->tv_sec -= b->tv_sec;
1011         a->tv_usec -= b->tv_usec;
1012         while ( a->tv_usec < 0 ) {
1013                 a->tv_sec--;
1014                 a->tv_usec += 1000000;
1015         }
1016 }
1017
1018 static unsigned int o2hb_elapsed_msecs(struct timeval *start,
1019                                        struct timeval *end)
1020 {
1021         struct timeval res = *end;
1022
1023         o2hb_tv_subtract(&res, start);
1024
1025         return res.tv_sec * 1000 + res.tv_usec / 1000;
1026 }
1027
1028 /*
1029  * we ride the region ref that the region dir holds.  before the region
1030  * dir is removed and drops it ref it will wait to tear down this
1031  * thread.
1032  */
1033 static int o2hb_thread(void *data)
1034 {
1035         int i, ret;
1036         struct o2hb_region *reg = data;
1037         struct o2hb_bio_wait_ctxt write_wc;
1038         struct timeval before_hb, after_hb;
1039         unsigned int elapsed_msec;
1040
1041         mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread running\n");
1042
1043         set_user_nice(current, -20);
1044
1045         while (!kthread_should_stop() && !reg->hr_unclean_stop) {
1046                 /* We track the time spent inside
1047                  * o2hb_do_disk_heartbeat so that we avoid more than
1048                  * hr_timeout_ms between disk writes. On busy systems
1049                  * this should result in a heartbeat which is less
1050                  * likely to time itself out. */
1051                 do_gettimeofday(&before_hb);
1052
1053                 i = 0;
1054                 do {
1055                         ret = o2hb_do_disk_heartbeat(reg);
1056                 } while (ret && ++i < 2);
1057
1058                 do_gettimeofday(&after_hb);
1059                 elapsed_msec = o2hb_elapsed_msecs(&before_hb, &after_hb);
1060
1061                 mlog(ML_HEARTBEAT,
1062                      "start = %lu.%lu, end = %lu.%lu, msec = %u\n",
1063                      before_hb.tv_sec, (unsigned long) before_hb.tv_usec,
1064                      after_hb.tv_sec, (unsigned long) after_hb.tv_usec,
1065                      elapsed_msec);
1066
1067                 if (elapsed_msec < reg->hr_timeout_ms) {
1068                         /* the kthread api has blocked signals for us so no
1069                          * need to record the return value. */
1070                         msleep_interruptible(reg->hr_timeout_ms - elapsed_msec);
1071                 }
1072         }
1073
1074         o2hb_disarm_write_timeout(reg);
1075
1076         /* unclean stop is only used in very bad situation */
1077         for(i = 0; !reg->hr_unclean_stop && i < reg->hr_blocks; i++)
1078                 o2hb_shutdown_slot(&reg->hr_slots[i]);
1079
1080         /* Explicit down notification - avoid forcing the other nodes
1081          * to timeout on this region when we could just as easily
1082          * write a clear generation - thus indicating to them that
1083          * this node has left this region.
1084          *
1085          * XXX: Should we skip this on unclean_stop? */
1086         o2hb_prepare_block(reg, 0);
1087         ret = o2hb_issue_node_write(reg, &write_wc);
1088         if (ret == 0) {
1089                 o2hb_wait_on_io(reg, &write_wc);
1090         } else {
1091                 mlog_errno(ret);
1092         }
1093
1094         mlog(ML_HEARTBEAT|ML_KTHREAD, "hb thread exiting\n");
1095
1096         return 0;
1097 }
1098
1099 #ifdef CONFIG_DEBUG_FS
1100 static int o2hb_debug_open(struct inode *inode, struct file *file)
1101 {
1102         struct o2hb_debug_buf *db = inode->i_private;
1103         struct o2hb_region *reg;
1104         unsigned long map[BITS_TO_LONGS(O2NM_MAX_NODES)];
1105         char *buf = NULL;
1106         int i = -1;
1107         int out = 0;
1108
1109         /* max_nodes should be the largest bitmap we pass here */
1110         BUG_ON(sizeof(map) < db->db_size);
1111
1112         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
1113         if (!buf)
1114                 goto bail;
1115
1116         switch (db->db_type) {
1117         case O2HB_DB_TYPE_LIVENODES:
1118         case O2HB_DB_TYPE_LIVEREGIONS:
1119         case O2HB_DB_TYPE_QUORUMREGIONS:
1120         case O2HB_DB_TYPE_FAILEDREGIONS:
1121                 spin_lock(&o2hb_live_lock);
1122                 memcpy(map, db->db_data, db->db_size);
1123                 spin_unlock(&o2hb_live_lock);
1124                 break;
1125
1126         case O2HB_DB_TYPE_REGION_LIVENODES:
1127                 spin_lock(&o2hb_live_lock);
1128                 reg = (struct o2hb_region *)db->db_data;
1129                 memcpy(map, reg->hr_live_node_bitmap, db->db_size);
1130                 spin_unlock(&o2hb_live_lock);
1131                 break;
1132
1133         case O2HB_DB_TYPE_REGION_NUMBER:
1134                 reg = (struct o2hb_region *)db->db_data;
1135                 out += snprintf(buf + out, PAGE_SIZE - out, "%d\n",
1136                                 reg->hr_region_num);
1137                 goto done;
1138
1139         case O2HB_DB_TYPE_REGION_ELAPSED_TIME:
1140                 reg = (struct o2hb_region *)db->db_data;
1141                 out += snprintf(buf + out, PAGE_SIZE - out, "%u\n",
1142                                 jiffies_to_msecs(jiffies -
1143                                                  reg->hr_last_timeout_start));
1144                 goto done;
1145
1146         default:
1147                 goto done;
1148         }
1149
1150         while ((i = find_next_bit(map, db->db_len, i + 1)) < db->db_len)
1151                 out += snprintf(buf + out, PAGE_SIZE - out, "%d ", i);
1152         out += snprintf(buf + out, PAGE_SIZE - out, "\n");
1153
1154 done:
1155         i_size_write(inode, out);
1156
1157         file->private_data = buf;
1158
1159         return 0;
1160 bail:
1161         return -ENOMEM;
1162 }
1163
1164 static int o2hb_debug_release(struct inode *inode, struct file *file)
1165 {
1166         kfree(file->private_data);
1167         return 0;
1168 }
1169
1170 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1171                                  size_t nbytes, loff_t *ppos)
1172 {
1173         return simple_read_from_buffer(buf, nbytes, ppos, file->private_data,
1174                                        i_size_read(file->f_mapping->host));
1175 }
1176 #else
1177 static int o2hb_debug_open(struct inode *inode, struct file *file)
1178 {
1179         return 0;
1180 }
1181 static int o2hb_debug_release(struct inode *inode, struct file *file)
1182 {
1183         return 0;
1184 }
1185 static ssize_t o2hb_debug_read(struct file *file, char __user *buf,
1186                                size_t nbytes, loff_t *ppos)
1187 {
1188         return 0;
1189 }
1190 #endif  /* CONFIG_DEBUG_FS */
1191
1192 static const struct file_operations o2hb_debug_fops = {
1193         .open =         o2hb_debug_open,
1194         .release =      o2hb_debug_release,
1195         .read =         o2hb_debug_read,
1196         .llseek =       generic_file_llseek,
1197 };
1198
1199 void o2hb_exit(void)
1200 {
1201         kfree(o2hb_db_livenodes);
1202         kfree(o2hb_db_liveregions);
1203         kfree(o2hb_db_quorumregions);
1204         kfree(o2hb_db_failedregions);
1205         debugfs_remove(o2hb_debug_failedregions);
1206         debugfs_remove(o2hb_debug_quorumregions);
1207         debugfs_remove(o2hb_debug_liveregions);
1208         debugfs_remove(o2hb_debug_livenodes);
1209         debugfs_remove(o2hb_debug_dir);
1210 }
1211
1212 static struct dentry *o2hb_debug_create(const char *name, struct dentry *dir,
1213                                         struct o2hb_debug_buf **db, int db_len,
1214                                         int type, int size, int len, void *data)
1215 {
1216         *db = kmalloc(db_len, GFP_KERNEL);
1217         if (!*db)
1218                 return NULL;
1219
1220         (*db)->db_type = type;
1221         (*db)->db_size = size;
1222         (*db)->db_len = len;
1223         (*db)->db_data = data;
1224
1225         return debugfs_create_file(name, S_IFREG|S_IRUSR, dir, *db,
1226                                    &o2hb_debug_fops);
1227 }
1228
1229 static int o2hb_debug_init(void)
1230 {
1231         int ret = -ENOMEM;
1232
1233         o2hb_debug_dir = debugfs_create_dir(O2HB_DEBUG_DIR, NULL);
1234         if (!o2hb_debug_dir) {
1235                 mlog_errno(ret);
1236                 goto bail;
1237         }
1238
1239         o2hb_debug_livenodes = o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1240                                                  o2hb_debug_dir,
1241                                                  &o2hb_db_livenodes,
1242                                                  sizeof(*o2hb_db_livenodes),
1243                                                  O2HB_DB_TYPE_LIVENODES,
1244                                                  sizeof(o2hb_live_node_bitmap),
1245                                                  O2NM_MAX_NODES,
1246                                                  o2hb_live_node_bitmap);
1247         if (!o2hb_debug_livenodes) {
1248                 mlog_errno(ret);
1249                 goto bail;
1250         }
1251
1252         o2hb_debug_liveregions = o2hb_debug_create(O2HB_DEBUG_LIVEREGIONS,
1253                                                    o2hb_debug_dir,
1254                                                    &o2hb_db_liveregions,
1255                                                    sizeof(*o2hb_db_liveregions),
1256                                                    O2HB_DB_TYPE_LIVEREGIONS,
1257                                                    sizeof(o2hb_live_region_bitmap),
1258                                                    O2NM_MAX_REGIONS,
1259                                                    o2hb_live_region_bitmap);
1260         if (!o2hb_debug_liveregions) {
1261                 mlog_errno(ret);
1262                 goto bail;
1263         }
1264
1265         o2hb_debug_quorumregions =
1266                         o2hb_debug_create(O2HB_DEBUG_QUORUMREGIONS,
1267                                           o2hb_debug_dir,
1268                                           &o2hb_db_quorumregions,
1269                                           sizeof(*o2hb_db_quorumregions),
1270                                           O2HB_DB_TYPE_QUORUMREGIONS,
1271                                           sizeof(o2hb_quorum_region_bitmap),
1272                                           O2NM_MAX_REGIONS,
1273                                           o2hb_quorum_region_bitmap);
1274         if (!o2hb_debug_quorumregions) {
1275                 mlog_errno(ret);
1276                 goto bail;
1277         }
1278
1279         o2hb_debug_failedregions =
1280                         o2hb_debug_create(O2HB_DEBUG_FAILEDREGIONS,
1281                                           o2hb_debug_dir,
1282                                           &o2hb_db_failedregions,
1283                                           sizeof(*o2hb_db_failedregions),
1284                                           O2HB_DB_TYPE_FAILEDREGIONS,
1285                                           sizeof(o2hb_failed_region_bitmap),
1286                                           O2NM_MAX_REGIONS,
1287                                           o2hb_failed_region_bitmap);
1288         if (!o2hb_debug_failedregions) {
1289                 mlog_errno(ret);
1290                 goto bail;
1291         }
1292
1293         ret = 0;
1294 bail:
1295         if (ret)
1296                 o2hb_exit();
1297
1298         return ret;
1299 }
1300
1301 int o2hb_init(void)
1302 {
1303         int i;
1304
1305         for (i = 0; i < ARRAY_SIZE(o2hb_callbacks); i++)
1306                 INIT_LIST_HEAD(&o2hb_callbacks[i].list);
1307
1308         for (i = 0; i < ARRAY_SIZE(o2hb_live_slots); i++)
1309                 INIT_LIST_HEAD(&o2hb_live_slots[i]);
1310
1311         INIT_LIST_HEAD(&o2hb_node_events);
1312
1313         memset(o2hb_live_node_bitmap, 0, sizeof(o2hb_live_node_bitmap));
1314         memset(o2hb_region_bitmap, 0, sizeof(o2hb_region_bitmap));
1315         memset(o2hb_live_region_bitmap, 0, sizeof(o2hb_live_region_bitmap));
1316         memset(o2hb_quorum_region_bitmap, 0, sizeof(o2hb_quorum_region_bitmap));
1317         memset(o2hb_failed_region_bitmap, 0, sizeof(o2hb_failed_region_bitmap));
1318
1319         return o2hb_debug_init();
1320 }
1321
1322 /* if we're already in a callback then we're already serialized by the sem */
1323 static void o2hb_fill_node_map_from_callback(unsigned long *map,
1324                                              unsigned bytes)
1325 {
1326         BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
1327
1328         memcpy(map, &o2hb_live_node_bitmap, bytes);
1329 }
1330
1331 /*
1332  * get a map of all nodes that are heartbeating in any regions
1333  */
1334 void o2hb_fill_node_map(unsigned long *map, unsigned bytes)
1335 {
1336         /* callers want to serialize this map and callbacks so that they
1337          * can trust that they don't miss nodes coming to the party */
1338         down_read(&o2hb_callback_sem);
1339         spin_lock(&o2hb_live_lock);
1340         o2hb_fill_node_map_from_callback(map, bytes);
1341         spin_unlock(&o2hb_live_lock);
1342         up_read(&o2hb_callback_sem);
1343 }
1344 EXPORT_SYMBOL_GPL(o2hb_fill_node_map);
1345
1346 /*
1347  * heartbeat configfs bits.  The heartbeat set is a default set under
1348  * the cluster set in nodemanager.c.
1349  */
1350
1351 static struct o2hb_region *to_o2hb_region(struct config_item *item)
1352 {
1353         return item ? container_of(item, struct o2hb_region, hr_item) : NULL;
1354 }
1355
1356 /* drop_item only drops its ref after killing the thread, nothing should
1357  * be using the region anymore.  this has to clean up any state that
1358  * attributes might have built up. */
1359 static void o2hb_region_release(struct config_item *item)
1360 {
1361         int i;
1362         struct page *page;
1363         struct o2hb_region *reg = to_o2hb_region(item);
1364
1365         if (reg->hr_tmp_block)
1366                 kfree(reg->hr_tmp_block);
1367
1368         if (reg->hr_slot_data) {
1369                 for (i = 0; i < reg->hr_num_pages; i++) {
1370                         page = reg->hr_slot_data[i];
1371                         if (page)
1372                                 __free_page(page);
1373                 }
1374                 kfree(reg->hr_slot_data);
1375         }
1376
1377         if (reg->hr_bdev)
1378                 blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1379
1380         if (reg->hr_slots)
1381                 kfree(reg->hr_slots);
1382
1383         kfree(reg->hr_db_regnum);
1384         kfree(reg->hr_db_livenodes);
1385         debugfs_remove(reg->hr_debug_livenodes);
1386         debugfs_remove(reg->hr_debug_regnum);
1387         debugfs_remove(reg->hr_debug_elapsed_time);
1388         debugfs_remove(reg->hr_debug_dir);
1389
1390         spin_lock(&o2hb_live_lock);
1391         list_del(&reg->hr_all_item);
1392         spin_unlock(&o2hb_live_lock);
1393
1394         kfree(reg);
1395 }
1396
1397 static int o2hb_read_block_input(struct o2hb_region *reg,
1398                                  const char *page,
1399                                  size_t count,
1400                                  unsigned long *ret_bytes,
1401                                  unsigned int *ret_bits)
1402 {
1403         unsigned long bytes;
1404         char *p = (char *)page;
1405
1406         bytes = simple_strtoul(p, &p, 0);
1407         if (!p || (*p && (*p != '\n')))
1408                 return -EINVAL;
1409
1410         /* Heartbeat and fs min / max block sizes are the same. */
1411         if (bytes > 4096 || bytes < 512)
1412                 return -ERANGE;
1413         if (hweight16(bytes) != 1)
1414                 return -EINVAL;
1415
1416         if (ret_bytes)
1417                 *ret_bytes = bytes;
1418         if (ret_bits)
1419                 *ret_bits = ffs(bytes) - 1;
1420
1421         return 0;
1422 }
1423
1424 static ssize_t o2hb_region_block_bytes_read(struct o2hb_region *reg,
1425                                             char *page)
1426 {
1427         return sprintf(page, "%u\n", reg->hr_block_bytes);
1428 }
1429
1430 static ssize_t o2hb_region_block_bytes_write(struct o2hb_region *reg,
1431                                              const char *page,
1432                                              size_t count)
1433 {
1434         int status;
1435         unsigned long block_bytes;
1436         unsigned int block_bits;
1437
1438         if (reg->hr_bdev)
1439                 return -EINVAL;
1440
1441         status = o2hb_read_block_input(reg, page, count,
1442                                        &block_bytes, &block_bits);
1443         if (status)
1444                 return status;
1445
1446         reg->hr_block_bytes = (unsigned int)block_bytes;
1447         reg->hr_block_bits = block_bits;
1448
1449         return count;
1450 }
1451
1452 static ssize_t o2hb_region_start_block_read(struct o2hb_region *reg,
1453                                             char *page)
1454 {
1455         return sprintf(page, "%llu\n", reg->hr_start_block);
1456 }
1457
1458 static ssize_t o2hb_region_start_block_write(struct o2hb_region *reg,
1459                                              const char *page,
1460                                              size_t count)
1461 {
1462         unsigned long long tmp;
1463         char *p = (char *)page;
1464
1465         if (reg->hr_bdev)
1466                 return -EINVAL;
1467
1468         tmp = simple_strtoull(p, &p, 0);
1469         if (!p || (*p && (*p != '\n')))
1470                 return -EINVAL;
1471
1472         reg->hr_start_block = tmp;
1473
1474         return count;
1475 }
1476
1477 static ssize_t o2hb_region_blocks_read(struct o2hb_region *reg,
1478                                        char *page)
1479 {
1480         return sprintf(page, "%d\n", reg->hr_blocks);
1481 }
1482
1483 static ssize_t o2hb_region_blocks_write(struct o2hb_region *reg,
1484                                         const char *page,
1485                                         size_t count)
1486 {
1487         unsigned long tmp;
1488         char *p = (char *)page;
1489
1490         if (reg->hr_bdev)
1491                 return -EINVAL;
1492
1493         tmp = simple_strtoul(p, &p, 0);
1494         if (!p || (*p && (*p != '\n')))
1495                 return -EINVAL;
1496
1497         if (tmp > O2NM_MAX_NODES || tmp == 0)
1498                 return -ERANGE;
1499
1500         reg->hr_blocks = (unsigned int)tmp;
1501
1502         return count;
1503 }
1504
1505 static ssize_t o2hb_region_dev_read(struct o2hb_region *reg,
1506                                     char *page)
1507 {
1508         unsigned int ret = 0;
1509
1510         if (reg->hr_bdev)
1511                 ret = sprintf(page, "%s\n", reg->hr_dev_name);
1512
1513         return ret;
1514 }
1515
1516 static void o2hb_init_region_params(struct o2hb_region *reg)
1517 {
1518         reg->hr_slots_per_page = PAGE_CACHE_SIZE >> reg->hr_block_bits;
1519         reg->hr_timeout_ms = O2HB_REGION_TIMEOUT_MS;
1520
1521         mlog(ML_HEARTBEAT, "hr_start_block = %llu, hr_blocks = %u\n",
1522              reg->hr_start_block, reg->hr_blocks);
1523         mlog(ML_HEARTBEAT, "hr_block_bytes = %u, hr_block_bits = %u\n",
1524              reg->hr_block_bytes, reg->hr_block_bits);
1525         mlog(ML_HEARTBEAT, "hr_timeout_ms = %u\n", reg->hr_timeout_ms);
1526         mlog(ML_HEARTBEAT, "dead threshold = %u\n", o2hb_dead_threshold);
1527 }
1528
1529 static int o2hb_map_slot_data(struct o2hb_region *reg)
1530 {
1531         int i, j;
1532         unsigned int last_slot;
1533         unsigned int spp = reg->hr_slots_per_page;
1534         struct page *page;
1535         char *raw;
1536         struct o2hb_disk_slot *slot;
1537
1538         reg->hr_tmp_block = kmalloc(reg->hr_block_bytes, GFP_KERNEL);
1539         if (reg->hr_tmp_block == NULL) {
1540                 mlog_errno(-ENOMEM);
1541                 return -ENOMEM;
1542         }
1543
1544         reg->hr_slots = kcalloc(reg->hr_blocks,
1545                                 sizeof(struct o2hb_disk_slot), GFP_KERNEL);
1546         if (reg->hr_slots == NULL) {
1547                 mlog_errno(-ENOMEM);
1548                 return -ENOMEM;
1549         }
1550
1551         for(i = 0; i < reg->hr_blocks; i++) {
1552                 slot = &reg->hr_slots[i];
1553                 slot->ds_node_num = i;
1554                 INIT_LIST_HEAD(&slot->ds_live_item);
1555                 slot->ds_raw_block = NULL;
1556         }
1557
1558         reg->hr_num_pages = (reg->hr_blocks + spp - 1) / spp;
1559         mlog(ML_HEARTBEAT, "Going to require %u pages to cover %u blocks "
1560                            "at %u blocks per page\n",
1561              reg->hr_num_pages, reg->hr_blocks, spp);
1562
1563         reg->hr_slot_data = kcalloc(reg->hr_num_pages, sizeof(struct page *),
1564                                     GFP_KERNEL);
1565         if (!reg->hr_slot_data) {
1566                 mlog_errno(-ENOMEM);
1567                 return -ENOMEM;
1568         }
1569
1570         for(i = 0; i < reg->hr_num_pages; i++) {
1571                 page = alloc_page(GFP_KERNEL);
1572                 if (!page) {
1573                         mlog_errno(-ENOMEM);
1574                         return -ENOMEM;
1575                 }
1576
1577                 reg->hr_slot_data[i] = page;
1578
1579                 last_slot = i * spp;
1580                 raw = page_address(page);
1581                 for (j = 0;
1582                      (j < spp) && ((j + last_slot) < reg->hr_blocks);
1583                      j++) {
1584                         BUG_ON((j + last_slot) >= reg->hr_blocks);
1585
1586                         slot = &reg->hr_slots[j + last_slot];
1587                         slot->ds_raw_block =
1588                                 (struct o2hb_disk_heartbeat_block *) raw;
1589
1590                         raw += reg->hr_block_bytes;
1591                 }
1592         }
1593
1594         return 0;
1595 }
1596
1597 /* Read in all the slots available and populate the tracking
1598  * structures so that we can start with a baseline idea of what's
1599  * there. */
1600 static int o2hb_populate_slot_data(struct o2hb_region *reg)
1601 {
1602         int ret, i;
1603         struct o2hb_disk_slot *slot;
1604         struct o2hb_disk_heartbeat_block *hb_block;
1605
1606         mlog_entry_void();
1607
1608         ret = o2hb_read_slots(reg, reg->hr_blocks);
1609         if (ret) {
1610                 mlog_errno(ret);
1611                 goto out;
1612         }
1613
1614         /* We only want to get an idea of the values initially in each
1615          * slot, so we do no verification - o2hb_check_slot will
1616          * actually determine if each configured slot is valid and
1617          * whether any values have changed. */
1618         for(i = 0; i < reg->hr_blocks; i++) {
1619                 slot = &reg->hr_slots[i];
1620                 hb_block = (struct o2hb_disk_heartbeat_block *) slot->ds_raw_block;
1621
1622                 /* Only fill the values that o2hb_check_slot uses to
1623                  * determine changing slots */
1624                 slot->ds_last_time = le64_to_cpu(hb_block->hb_seq);
1625                 slot->ds_last_generation = le64_to_cpu(hb_block->hb_generation);
1626         }
1627
1628 out:
1629         mlog_exit(ret);
1630         return ret;
1631 }
1632
1633 /* this is acting as commit; we set up all of hr_bdev and hr_task or nothing */
1634 static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
1635                                      const char *page,
1636                                      size_t count)
1637 {
1638         struct task_struct *hb_task;
1639         long fd;
1640         int sectsize;
1641         char *p = (char *)page;
1642         struct file *filp = NULL;
1643         struct inode *inode = NULL;
1644         ssize_t ret = -EINVAL;
1645
1646         if (reg->hr_bdev)
1647                 goto out;
1648
1649         /* We can't heartbeat without having had our node number
1650          * configured yet. */
1651         if (o2nm_this_node() == O2NM_MAX_NODES)
1652                 goto out;
1653
1654         fd = simple_strtol(p, &p, 0);
1655         if (!p || (*p && (*p != '\n')))
1656                 goto out;
1657
1658         if (fd < 0 || fd >= INT_MAX)
1659                 goto out;
1660
1661         filp = fget(fd);
1662         if (filp == NULL)
1663                 goto out;
1664
1665         if (reg->hr_blocks == 0 || reg->hr_start_block == 0 ||
1666             reg->hr_block_bytes == 0)
1667                 goto out;
1668
1669         inode = igrab(filp->f_mapping->host);
1670         if (inode == NULL)
1671                 goto out;
1672
1673         if (!S_ISBLK(inode->i_mode))
1674                 goto out;
1675
1676         reg->hr_bdev = I_BDEV(filp->f_mapping->host);
1677         ret = blkdev_get(reg->hr_bdev, FMODE_WRITE | FMODE_READ);
1678         if (ret) {
1679                 reg->hr_bdev = NULL;
1680                 goto out;
1681         }
1682         inode = NULL;
1683
1684         bdevname(reg->hr_bdev, reg->hr_dev_name);
1685
1686         sectsize = bdev_logical_block_size(reg->hr_bdev);
1687         if (sectsize != reg->hr_block_bytes) {
1688                 mlog(ML_ERROR,
1689                      "blocksize %u incorrect for device, expected %d",
1690                      reg->hr_block_bytes, sectsize);
1691                 ret = -EINVAL;
1692                 goto out;
1693         }
1694
1695         o2hb_init_region_params(reg);
1696
1697         /* Generation of zero is invalid */
1698         do {
1699                 get_random_bytes(&reg->hr_generation,
1700                                  sizeof(reg->hr_generation));
1701         } while (reg->hr_generation == 0);
1702
1703         ret = o2hb_map_slot_data(reg);
1704         if (ret) {
1705                 mlog_errno(ret);
1706                 goto out;
1707         }
1708
1709         ret = o2hb_populate_slot_data(reg);
1710         if (ret) {
1711                 mlog_errno(ret);
1712                 goto out;
1713         }
1714
1715         INIT_DELAYED_WORK(&reg->hr_write_timeout_work, o2hb_write_timeout);
1716
1717         /*
1718          * A node is considered live after it has beat LIVE_THRESHOLD
1719          * times.  We're not steady until we've given them a chance
1720          * _after_ our first read.
1721          */
1722         atomic_set(&reg->hr_steady_iterations, O2HB_LIVE_THRESHOLD + 1);
1723
1724         hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
1725                               reg->hr_item.ci_name);
1726         if (IS_ERR(hb_task)) {
1727                 ret = PTR_ERR(hb_task);
1728                 mlog_errno(ret);
1729                 goto out;
1730         }
1731
1732         spin_lock(&o2hb_live_lock);
1733         reg->hr_task = hb_task;
1734         spin_unlock(&o2hb_live_lock);
1735
1736         ret = wait_event_interruptible(o2hb_steady_queue,
1737                                 atomic_read(&reg->hr_steady_iterations) == 0);
1738         if (ret) {
1739                 /* We got interrupted (hello ptrace!).  Clean up */
1740                 spin_lock(&o2hb_live_lock);
1741                 hb_task = reg->hr_task;
1742                 reg->hr_task = NULL;
1743                 spin_unlock(&o2hb_live_lock);
1744
1745                 if (hb_task)
1746                         kthread_stop(hb_task);
1747                 goto out;
1748         }
1749
1750         /* Ok, we were woken.  Make sure it wasn't by drop_item() */
1751         spin_lock(&o2hb_live_lock);
1752         hb_task = reg->hr_task;
1753         if (o2hb_global_heartbeat_active())
1754                 set_bit(reg->hr_region_num, o2hb_live_region_bitmap);
1755         spin_unlock(&o2hb_live_lock);
1756
1757         if (hb_task)
1758                 ret = count;
1759         else
1760                 ret = -EIO;
1761
1762         if (hb_task && o2hb_global_heartbeat_active())
1763                 printk(KERN_NOTICE "o2hb: Heartbeat started on region %s\n",
1764                        config_item_name(&reg->hr_item));
1765
1766 out:
1767         if (filp)
1768                 fput(filp);
1769         if (inode)
1770                 iput(inode);
1771         if (ret < 0) {
1772                 if (reg->hr_bdev) {
1773                         blkdev_put(reg->hr_bdev, FMODE_READ|FMODE_WRITE);
1774                         reg->hr_bdev = NULL;
1775                 }
1776         }
1777         return ret;
1778 }
1779
1780 static ssize_t o2hb_region_pid_read(struct o2hb_region *reg,
1781                                       char *page)
1782 {
1783         pid_t pid = 0;
1784
1785         spin_lock(&o2hb_live_lock);
1786         if (reg->hr_task)
1787                 pid = task_pid_nr(reg->hr_task);
1788         spin_unlock(&o2hb_live_lock);
1789
1790         if (!pid)
1791                 return 0;
1792
1793         return sprintf(page, "%u\n", pid);
1794 }
1795
1796 struct o2hb_region_attribute {
1797         struct configfs_attribute attr;
1798         ssize_t (*show)(struct o2hb_region *, char *);
1799         ssize_t (*store)(struct o2hb_region *, const char *, size_t);
1800 };
1801
1802 static struct o2hb_region_attribute o2hb_region_attr_block_bytes = {
1803         .attr   = { .ca_owner = THIS_MODULE,
1804                     .ca_name = "block_bytes",
1805                     .ca_mode = S_IRUGO | S_IWUSR },
1806         .show   = o2hb_region_block_bytes_read,
1807         .store  = o2hb_region_block_bytes_write,
1808 };
1809
1810 static struct o2hb_region_attribute o2hb_region_attr_start_block = {
1811         .attr   = { .ca_owner = THIS_MODULE,
1812                     .ca_name = "start_block",
1813                     .ca_mode = S_IRUGO | S_IWUSR },
1814         .show   = o2hb_region_start_block_read,
1815         .store  = o2hb_region_start_block_write,
1816 };
1817
1818 static struct o2hb_region_attribute o2hb_region_attr_blocks = {
1819         .attr   = { .ca_owner = THIS_MODULE,
1820                     .ca_name = "blocks",
1821                     .ca_mode = S_IRUGO | S_IWUSR },
1822         .show   = o2hb_region_blocks_read,
1823         .store  = o2hb_region_blocks_write,
1824 };
1825
1826 static struct o2hb_region_attribute o2hb_region_attr_dev = {
1827         .attr   = { .ca_owner = THIS_MODULE,
1828                     .ca_name = "dev",
1829                     .ca_mode = S_IRUGO | S_IWUSR },
1830         .show   = o2hb_region_dev_read,
1831         .store  = o2hb_region_dev_write,
1832 };
1833
1834 static struct o2hb_region_attribute o2hb_region_attr_pid = {
1835        .attr   = { .ca_owner = THIS_MODULE,
1836                    .ca_name = "pid",
1837                    .ca_mode = S_IRUGO | S_IRUSR },
1838        .show   = o2hb_region_pid_read,
1839 };
1840
1841 static struct configfs_attribute *o2hb_region_attrs[] = {
1842         &o2hb_region_attr_block_bytes.attr,
1843         &o2hb_region_attr_start_block.attr,
1844         &o2hb_region_attr_blocks.attr,
1845         &o2hb_region_attr_dev.attr,
1846         &o2hb_region_attr_pid.attr,
1847         NULL,
1848 };
1849
1850 static ssize_t o2hb_region_show(struct config_item *item,
1851                                 struct configfs_attribute *attr,
1852                                 char *page)
1853 {
1854         struct o2hb_region *reg = to_o2hb_region(item);
1855         struct o2hb_region_attribute *o2hb_region_attr =
1856                 container_of(attr, struct o2hb_region_attribute, attr);
1857         ssize_t ret = 0;
1858
1859         if (o2hb_region_attr->show)
1860                 ret = o2hb_region_attr->show(reg, page);
1861         return ret;
1862 }
1863
1864 static ssize_t o2hb_region_store(struct config_item *item,
1865                                  struct configfs_attribute *attr,
1866                                  const char *page, size_t count)
1867 {
1868         struct o2hb_region *reg = to_o2hb_region(item);
1869         struct o2hb_region_attribute *o2hb_region_attr =
1870                 container_of(attr, struct o2hb_region_attribute, attr);
1871         ssize_t ret = -EINVAL;
1872
1873         if (o2hb_region_attr->store)
1874                 ret = o2hb_region_attr->store(reg, page, count);
1875         return ret;
1876 }
1877
1878 static struct configfs_item_operations o2hb_region_item_ops = {
1879         .release                = o2hb_region_release,
1880         .show_attribute         = o2hb_region_show,
1881         .store_attribute        = o2hb_region_store,
1882 };
1883
1884 static struct config_item_type o2hb_region_type = {
1885         .ct_item_ops    = &o2hb_region_item_ops,
1886         .ct_attrs       = o2hb_region_attrs,
1887         .ct_owner       = THIS_MODULE,
1888 };
1889
1890 /* heartbeat set */
1891
1892 struct o2hb_heartbeat_group {
1893         struct config_group hs_group;
1894         /* some stuff? */
1895 };
1896
1897 static struct o2hb_heartbeat_group *to_o2hb_heartbeat_group(struct config_group *group)
1898 {
1899         return group ?
1900                 container_of(group, struct o2hb_heartbeat_group, hs_group)
1901                 : NULL;
1902 }
1903
1904 static int o2hb_debug_region_init(struct o2hb_region *reg, struct dentry *dir)
1905 {
1906         int ret = -ENOMEM;
1907
1908         reg->hr_debug_dir =
1909                 debugfs_create_dir(config_item_name(&reg->hr_item), dir);
1910         if (!reg->hr_debug_dir) {
1911                 mlog_errno(ret);
1912                 goto bail;
1913         }
1914
1915         reg->hr_debug_livenodes =
1916                         o2hb_debug_create(O2HB_DEBUG_LIVENODES,
1917                                           reg->hr_debug_dir,
1918                                           &(reg->hr_db_livenodes),
1919                                           sizeof(*(reg->hr_db_livenodes)),
1920                                           O2HB_DB_TYPE_REGION_LIVENODES,
1921                                           sizeof(reg->hr_live_node_bitmap),
1922                                           O2NM_MAX_NODES, reg);
1923         if (!reg->hr_debug_livenodes) {
1924                 mlog_errno(ret);
1925                 goto bail;
1926         }
1927
1928         reg->hr_debug_regnum =
1929                         o2hb_debug_create(O2HB_DEBUG_REGION_NUMBER,
1930                                           reg->hr_debug_dir,
1931                                           &(reg->hr_db_regnum),
1932                                           sizeof(*(reg->hr_db_regnum)),
1933                                           O2HB_DB_TYPE_REGION_NUMBER,
1934                                           0, O2NM_MAX_NODES, reg);
1935         if (!reg->hr_debug_regnum) {
1936                 mlog_errno(ret);
1937                 goto bail;
1938         }
1939
1940         reg->hr_debug_elapsed_time =
1941                         o2hb_debug_create(O2HB_DEBUG_REGION_ELAPSED_TIME,
1942                                           reg->hr_debug_dir,
1943                                           &(reg->hr_db_elapsed_time),
1944                                           sizeof(*(reg->hr_db_elapsed_time)),
1945                                           O2HB_DB_TYPE_REGION_ELAPSED_TIME,
1946                                           0, 0, reg);
1947         if (!reg->hr_debug_elapsed_time) {
1948                 mlog_errno(ret);
1949                 goto bail;
1950         }
1951
1952         ret = 0;
1953 bail:
1954         return ret;
1955 }
1956
1957 static struct config_item *o2hb_heartbeat_group_make_item(struct config_group *group,
1958                                                           const char *name)
1959 {
1960         struct o2hb_region *reg = NULL;
1961         int ret;
1962
1963         reg = kzalloc(sizeof(struct o2hb_region), GFP_KERNEL);
1964         if (reg == NULL)
1965                 return ERR_PTR(-ENOMEM);
1966
1967         if (strlen(name) > O2HB_MAX_REGION_NAME_LEN) {
1968                 ret = -ENAMETOOLONG;
1969                 goto free;
1970         }
1971
1972         spin_lock(&o2hb_live_lock);
1973         reg->hr_region_num = 0;
1974         if (o2hb_global_heartbeat_active()) {
1975                 reg->hr_region_num = find_first_zero_bit(o2hb_region_bitmap,
1976                                                          O2NM_MAX_REGIONS);
1977                 if (reg->hr_region_num >= O2NM_MAX_REGIONS) {
1978                         spin_unlock(&o2hb_live_lock);
1979                         ret = -EFBIG;
1980                         goto free;
1981                 }
1982                 set_bit(reg->hr_region_num, o2hb_region_bitmap);
1983         }
1984         list_add_tail(&reg->hr_all_item, &o2hb_all_regions);
1985         spin_unlock(&o2hb_live_lock);
1986
1987         config_item_init_type_name(&reg->hr_item, name, &o2hb_region_type);
1988
1989         ret = o2hb_debug_region_init(reg, o2hb_debug_dir);
1990         if (ret) {
1991                 config_item_put(&reg->hr_item);
1992                 goto free;
1993         }
1994
1995         return &reg->hr_item;
1996 free:
1997         kfree(reg);
1998         return ERR_PTR(ret);
1999 }
2000
2001 static void o2hb_heartbeat_group_drop_item(struct config_group *group,
2002                                            struct config_item *item)
2003 {
2004         struct task_struct *hb_task;
2005         struct o2hb_region *reg = to_o2hb_region(item);
2006
2007         /* stop the thread when the user removes the region dir */
2008         spin_lock(&o2hb_live_lock);
2009         if (o2hb_global_heartbeat_active()) {
2010                 clear_bit(reg->hr_region_num, o2hb_region_bitmap);
2011                 clear_bit(reg->hr_region_num, o2hb_live_region_bitmap);
2012         }
2013         hb_task = reg->hr_task;
2014         reg->hr_task = NULL;
2015         spin_unlock(&o2hb_live_lock);
2016
2017         if (hb_task)
2018                 kthread_stop(hb_task);
2019
2020         /*
2021          * If we're racing a dev_write(), we need to wake them.  They will
2022          * check reg->hr_task
2023          */
2024         if (atomic_read(&reg->hr_steady_iterations) != 0) {
2025                 atomic_set(&reg->hr_steady_iterations, 0);
2026                 wake_up(&o2hb_steady_queue);
2027         }
2028
2029         if (o2hb_global_heartbeat_active())
2030                 printk(KERN_NOTICE "o2hb: Heartbeat stopped on region %s\n",
2031                        config_item_name(&reg->hr_item));
2032         config_item_put(item);
2033 }
2034
2035 struct o2hb_heartbeat_group_attribute {
2036         struct configfs_attribute attr;
2037         ssize_t (*show)(struct o2hb_heartbeat_group *, char *);
2038         ssize_t (*store)(struct o2hb_heartbeat_group *, const char *, size_t);
2039 };
2040
2041 static ssize_t o2hb_heartbeat_group_show(struct config_item *item,
2042                                          struct configfs_attribute *attr,
2043                                          char *page)
2044 {
2045         struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
2046         struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
2047                 container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
2048         ssize_t ret = 0;
2049
2050         if (o2hb_heartbeat_group_attr->show)
2051                 ret = o2hb_heartbeat_group_attr->show(reg, page);
2052         return ret;
2053 }
2054
2055 static ssize_t o2hb_heartbeat_group_store(struct config_item *item,
2056                                           struct configfs_attribute *attr,
2057                                           const char *page, size_t count)
2058 {
2059         struct o2hb_heartbeat_group *reg = to_o2hb_heartbeat_group(to_config_group(item));
2060         struct o2hb_heartbeat_group_attribute *o2hb_heartbeat_group_attr =
2061                 container_of(attr, struct o2hb_heartbeat_group_attribute, attr);
2062         ssize_t ret = -EINVAL;
2063
2064         if (o2hb_heartbeat_group_attr->store)
2065                 ret = o2hb_heartbeat_group_attr->store(reg, page, count);
2066         return ret;
2067 }
2068
2069 static ssize_t o2hb_heartbeat_group_threshold_show(struct o2hb_heartbeat_group *group,
2070                                                      char *page)
2071 {
2072         return sprintf(page, "%u\n", o2hb_dead_threshold);
2073 }
2074
2075 static ssize_t o2hb_heartbeat_group_threshold_store(struct o2hb_heartbeat_group *group,
2076                                                     const char *page,
2077                                                     size_t count)
2078 {
2079         unsigned long tmp;
2080         char *p = (char *)page;
2081
2082         tmp = simple_strtoul(p, &p, 10);
2083         if (!p || (*p && (*p != '\n')))
2084                 return -EINVAL;
2085
2086         /* this will validate ranges for us. */
2087         o2hb_dead_threshold_set((unsigned int) tmp);
2088
2089         return count;
2090 }
2091
2092 static
2093 ssize_t o2hb_heartbeat_group_mode_show(struct o2hb_heartbeat_group *group,
2094                                        char *page)
2095 {
2096         return sprintf(page, "%s\n",
2097                        o2hb_heartbeat_mode_desc[o2hb_heartbeat_mode]);
2098 }
2099
2100 static
2101 ssize_t o2hb_heartbeat_group_mode_store(struct o2hb_heartbeat_group *group,
2102                                         const char *page, size_t count)
2103 {
2104         unsigned int i;
2105         int ret;
2106         size_t len;
2107
2108         len = (page[count - 1] == '\n') ? count - 1 : count;
2109         if (!len)
2110                 return -EINVAL;
2111
2112         for (i = 0; i < O2HB_HEARTBEAT_NUM_MODES; ++i) {
2113                 if (strnicmp(page, o2hb_heartbeat_mode_desc[i], len))
2114                         continue;
2115
2116                 ret = o2hb_global_hearbeat_mode_set(i);
2117                 if (!ret)
2118                         printk(KERN_NOTICE "o2hb: Heartbeat mode set to %s\n",
2119                                o2hb_heartbeat_mode_desc[i]);
2120                 return count;
2121         }
2122
2123         return -EINVAL;
2124
2125 }
2126
2127 static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_threshold = {
2128         .attr   = { .ca_owner = THIS_MODULE,
2129                     .ca_name = "dead_threshold",
2130                     .ca_mode = S_IRUGO | S_IWUSR },
2131         .show   = o2hb_heartbeat_group_threshold_show,
2132         .store  = o2hb_heartbeat_group_threshold_store,
2133 };
2134
2135 static struct o2hb_heartbeat_group_attribute o2hb_heartbeat_group_attr_mode = {
2136         .attr   = { .ca_owner = THIS_MODULE,
2137                 .ca_name = "mode",
2138                 .ca_mode = S_IRUGO | S_IWUSR },
2139         .show   = o2hb_heartbeat_group_mode_show,
2140         .store  = o2hb_heartbeat_group_mode_store,
2141 };
2142
2143 static struct configfs_attribute *o2hb_heartbeat_group_attrs[] = {
2144         &o2hb_heartbeat_group_attr_threshold.attr,
2145         &o2hb_heartbeat_group_attr_mode.attr,
2146         NULL,
2147 };
2148
2149 static struct configfs_item_operations o2hb_hearbeat_group_item_ops = {
2150         .show_attribute         = o2hb_heartbeat_group_show,
2151         .store_attribute        = o2hb_heartbeat_group_store,
2152 };
2153
2154 static struct configfs_group_operations o2hb_heartbeat_group_group_ops = {
2155         .make_item      = o2hb_heartbeat_group_make_item,
2156         .drop_item      = o2hb_heartbeat_group_drop_item,
2157 };
2158
2159 static struct config_item_type o2hb_heartbeat_group_type = {
2160         .ct_group_ops   = &o2hb_heartbeat_group_group_ops,
2161         .ct_item_ops    = &o2hb_hearbeat_group_item_ops,
2162         .ct_attrs       = o2hb_heartbeat_group_attrs,
2163         .ct_owner       = THIS_MODULE,
2164 };
2165
2166 /* this is just here to avoid touching group in heartbeat.h which the
2167  * entire damn world #includes */
2168 struct config_group *o2hb_alloc_hb_set(void)
2169 {
2170         struct o2hb_heartbeat_group *hs = NULL;
2171         struct config_group *ret = NULL;
2172
2173         hs = kzalloc(sizeof(struct o2hb_heartbeat_group), GFP_KERNEL);
2174         if (hs == NULL)
2175                 goto out;
2176
2177         config_group_init_type_name(&hs->hs_group, "heartbeat",
2178                                     &o2hb_heartbeat_group_type);
2179
2180         ret = &hs->hs_group;
2181 out:
2182         if (ret == NULL)
2183                 kfree(hs);
2184         return ret;
2185 }
2186
2187 void o2hb_free_hb_set(struct config_group *group)
2188 {
2189         struct o2hb_heartbeat_group *hs = to_o2hb_heartbeat_group(group);
2190         kfree(hs);
2191 }
2192
2193 /* hb callback registration and issueing */
2194
2195 static struct o2hb_callback *hbcall_from_type(enum o2hb_callback_type type)
2196 {
2197         if (type == O2HB_NUM_CB)
2198                 return ERR_PTR(-EINVAL);
2199
2200         return &o2hb_callbacks[type];
2201 }
2202
2203 void o2hb_setup_callback(struct o2hb_callback_func *hc,
2204                          enum o2hb_callback_type type,
2205                          o2hb_cb_func *func,
2206                          void *data,
2207                          int priority)
2208 {
2209         INIT_LIST_HEAD(&hc->hc_item);
2210         hc->hc_func = func;
2211         hc->hc_data = data;
2212         hc->hc_priority = priority;
2213         hc->hc_type = type;
2214         hc->hc_magic = O2HB_CB_MAGIC;
2215 }
2216 EXPORT_SYMBOL_GPL(o2hb_setup_callback);
2217
2218 static struct o2hb_region *o2hb_find_region(const char *region_uuid)
2219 {
2220         struct o2hb_region *p, *reg = NULL;
2221
2222         assert_spin_locked(&o2hb_live_lock);
2223
2224         list_for_each_entry(p, &o2hb_all_regions, hr_all_item) {
2225                 if (!strcmp(region_uuid, config_item_name(&p->hr_item))) {
2226                         reg = p;
2227                         break;
2228                 }
2229         }
2230
2231         return reg;
2232 }
2233
2234 static int o2hb_region_get(const char *region_uuid)
2235 {
2236         int ret = 0;
2237         struct o2hb_region *reg;
2238
2239         spin_lock(&o2hb_live_lock);
2240
2241         reg = o2hb_find_region(region_uuid);
2242         if (!reg)
2243                 ret = -ENOENT;
2244         spin_unlock(&o2hb_live_lock);
2245
2246         if (ret)
2247                 goto out;
2248
2249         ret = o2nm_depend_this_node();
2250         if (ret)
2251                 goto out;
2252
2253         ret = o2nm_depend_item(&reg->hr_item);
2254         if (ret)
2255                 o2nm_undepend_this_node();
2256
2257 out:
2258         return ret;
2259 }
2260
2261 static void o2hb_region_put(const char *region_uuid)
2262 {
2263         struct o2hb_region *reg;
2264
2265         spin_lock(&o2hb_live_lock);
2266
2267         reg = o2hb_find_region(region_uuid);
2268
2269         spin_unlock(&o2hb_live_lock);
2270
2271         if (reg) {
2272                 o2nm_undepend_item(&reg->hr_item);
2273                 o2nm_undepend_this_node();
2274         }
2275 }
2276
2277 int o2hb_register_callback(const char *region_uuid,
2278                            struct o2hb_callback_func *hc)
2279 {
2280         struct o2hb_callback_func *tmp;
2281         struct list_head *iter;
2282         struct o2hb_callback *hbcall;
2283         int ret;
2284
2285         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2286         BUG_ON(!list_empty(&hc->hc_item));
2287
2288         hbcall = hbcall_from_type(hc->hc_type);
2289         if (IS_ERR(hbcall)) {
2290                 ret = PTR_ERR(hbcall);
2291                 goto out;
2292         }
2293
2294         if (region_uuid) {
2295                 ret = o2hb_region_get(region_uuid);
2296                 if (ret)
2297                         goto out;
2298         }
2299
2300         down_write(&o2hb_callback_sem);
2301
2302         list_for_each(iter, &hbcall->list) {
2303                 tmp = list_entry(iter, struct o2hb_callback_func, hc_item);
2304                 if (hc->hc_priority < tmp->hc_priority) {
2305                         list_add_tail(&hc->hc_item, iter);
2306                         break;
2307                 }
2308         }
2309         if (list_empty(&hc->hc_item))
2310                 list_add_tail(&hc->hc_item, &hbcall->list);
2311
2312         up_write(&o2hb_callback_sem);
2313         ret = 0;
2314 out:
2315         mlog(ML_HEARTBEAT, "returning %d on behalf of %p for funcs %p\n",
2316              ret, __builtin_return_address(0), hc);
2317         return ret;
2318 }
2319 EXPORT_SYMBOL_GPL(o2hb_register_callback);
2320
2321 void o2hb_unregister_callback(const char *region_uuid,
2322                               struct o2hb_callback_func *hc)
2323 {
2324         BUG_ON(hc->hc_magic != O2HB_CB_MAGIC);
2325
2326         mlog(ML_HEARTBEAT, "on behalf of %p for funcs %p\n",
2327              __builtin_return_address(0), hc);
2328
2329         /* XXX Can this happen _with_ a region reference? */
2330         if (list_empty(&hc->hc_item))
2331                 return;
2332
2333         if (region_uuid)
2334                 o2hb_region_put(region_uuid);
2335
2336         down_write(&o2hb_callback_sem);
2337
2338         list_del_init(&hc->hc_item);
2339
2340         up_write(&o2hb_callback_sem);
2341 }
2342 EXPORT_SYMBOL_GPL(o2hb_unregister_callback);
2343
2344 int o2hb_check_node_heartbeating(u8 node_num)
2345 {
2346         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2347
2348         o2hb_fill_node_map(testing_map, sizeof(testing_map));
2349         if (!test_bit(node_num, testing_map)) {
2350                 mlog(ML_HEARTBEAT,
2351                      "node (%u) does not have heartbeating enabled.\n",
2352                      node_num);
2353                 return 0;
2354         }
2355
2356         return 1;
2357 }
2358 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating);
2359
2360 int o2hb_check_node_heartbeating_from_callback(u8 node_num)
2361 {
2362         unsigned long testing_map[BITS_TO_LONGS(O2NM_MAX_NODES)];
2363
2364         o2hb_fill_node_map_from_callback(testing_map, sizeof(testing_map));
2365         if (!test_bit(node_num, testing_map)) {
2366                 mlog(ML_HEARTBEAT,
2367                      "node (%u) does not have heartbeating enabled.\n",
2368                      node_num);
2369                 return 0;
2370         }
2371
2372         return 1;
2373 }
2374 EXPORT_SYMBOL_GPL(o2hb_check_node_heartbeating_from_callback);
2375
2376 /* Makes sure our local node is configured with a node number, and is
2377  * heartbeating. */
2378 int o2hb_check_local_node_heartbeating(void)
2379 {
2380         u8 node_num;
2381
2382         /* if this node was set then we have networking */
2383         node_num = o2nm_this_node();
2384         if (node_num == O2NM_MAX_NODES) {
2385                 mlog(ML_HEARTBEAT, "this node has not been configured.\n");
2386                 return 0;
2387         }
2388
2389         return o2hb_check_node_heartbeating(node_num);
2390 }
2391 EXPORT_SYMBOL_GPL(o2hb_check_local_node_heartbeating);
2392
2393 /*
2394  * this is just a hack until we get the plumbing which flips file systems
2395  * read only and drops the hb ref instead of killing the node dead.
2396  */
2397 void o2hb_stop_all_regions(void)
2398 {
2399         struct o2hb_region *reg;
2400
2401         mlog(ML_ERROR, "stopping heartbeat on all active regions.\n");
2402
2403         spin_lock(&o2hb_live_lock);
2404
2405         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item)
2406                 reg->hr_unclean_stop = 1;
2407
2408         spin_unlock(&o2hb_live_lock);
2409 }
2410 EXPORT_SYMBOL_GPL(o2hb_stop_all_regions);
2411
2412 int o2hb_get_all_regions(char *region_uuids, u8 max_regions)
2413 {
2414         struct o2hb_region *reg;
2415         int numregs = 0;
2416         char *p;
2417
2418         spin_lock(&o2hb_live_lock);
2419
2420         p = region_uuids;
2421         list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2422                 mlog(0, "Region: %s\n", config_item_name(&reg->hr_item));
2423                 if (numregs < max_regions) {
2424                         memcpy(p, config_item_name(&reg->hr_item),
2425                                O2HB_MAX_REGION_NAME_LEN);
2426                         p += O2HB_MAX_REGION_NAME_LEN;
2427                 }
2428                 numregs++;
2429         }
2430
2431         spin_unlock(&o2hb_live_lock);
2432
2433         return numregs;
2434 }
2435 EXPORT_SYMBOL_GPL(o2hb_get_all_regions);
2436
2437 int o2hb_global_heartbeat_active(void)
2438 {
2439         return (o2hb_heartbeat_mode == O2HB_HEARTBEAT_GLOBAL);
2440 }
2441 EXPORT_SYMBOL(o2hb_global_heartbeat_active);