linux/fs/ocfs2/dlm/dlmmaster.c
<<
>>
Prefs
   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * dlmmod.c
   4 *
   5 * standalone DLM module
   6 *
   7 * Copyright (C) 2004 Oracle.  All rights reserved.
   8 */
   9
  10
  11#include <linux/module.h>
  12#include <linux/fs.h>
  13#include <linux/types.h>
  14#include <linux/slab.h>
  15#include <linux/highmem.h>
  16#include <linux/init.h>
  17#include <linux/sysctl.h>
  18#include <linux/random.h>
  19#include <linux/blkdev.h>
  20#include <linux/socket.h>
  21#include <linux/inet.h>
  22#include <linux/spinlock.h>
  23#include <linux/delay.h>
  24
  25
  26#include "../cluster/heartbeat.h"
  27#include "../cluster/nodemanager.h"
  28#include "../cluster/tcp.h"
  29
  30#include "dlmapi.h"
  31#include "dlmcommon.h"
  32#include "dlmdomain.h"
  33#include "dlmdebug.h"
  34
  35#define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER)
  36#include "../cluster/masklog.h"
  37
  38static void dlm_mle_node_down(struct dlm_ctxt *dlm,
  39                              struct dlm_master_list_entry *mle,
  40                              struct o2nm_node *node,
  41                              int idx);
  42static void dlm_mle_node_up(struct dlm_ctxt *dlm,
  43                            struct dlm_master_list_entry *mle,
  44                            struct o2nm_node *node,
  45                            int idx);
  46
  47static void dlm_assert_master_worker(struct dlm_work_item *item, void *data);
  48static int dlm_do_assert_master(struct dlm_ctxt *dlm,
  49                                struct dlm_lock_resource *res,
  50                                void *nodemap, u32 flags);
  51static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data);
  52
  53static inline int dlm_mle_equal(struct dlm_ctxt *dlm,
  54                                struct dlm_master_list_entry *mle,
  55                                const char *name,
  56                                unsigned int namelen)
  57{
  58        if (dlm != mle->dlm)
  59                return 0;
  60
  61        if (namelen != mle->mnamelen ||
  62            memcmp(name, mle->mname, namelen) != 0)
  63                return 0;
  64
  65        return 1;
  66}
  67
  68static struct kmem_cache *dlm_lockres_cache;
  69static struct kmem_cache *dlm_lockname_cache;
  70static struct kmem_cache *dlm_mle_cache;
  71
  72static void dlm_mle_release(struct kref *kref);
  73static void dlm_init_mle(struct dlm_master_list_entry *mle,
  74                        enum dlm_mle_type type,
  75                        struct dlm_ctxt *dlm,
  76                        struct dlm_lock_resource *res,
  77                        const char *name,
  78                        unsigned int namelen);
  79static void dlm_put_mle(struct dlm_master_list_entry *mle);
  80static void __dlm_put_mle(struct dlm_master_list_entry *mle);
  81static int dlm_find_mle(struct dlm_ctxt *dlm,
  82                        struct dlm_master_list_entry **mle,
  83                        char *name, unsigned int namelen);
  84
  85static int dlm_do_master_request(struct dlm_lock_resource *res,
  86                                 struct dlm_master_list_entry *mle, int to);
  87
  88
  89static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
  90                                     struct dlm_lock_resource *res,
  91                                     struct dlm_master_list_entry *mle,
  92                                     int *blocked);
  93static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
  94                                    struct dlm_lock_resource *res,
  95                                    struct dlm_master_list_entry *mle,
  96                                    int blocked);
  97static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
  98                                 struct dlm_lock_resource *res,
  99                                 struct dlm_master_list_entry *mle,
 100                                 struct dlm_master_list_entry **oldmle,
 101                                 const char *name, unsigned int namelen,
 102                                 u8 new_master, u8 master);
 103
 104static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
 105                                    struct dlm_lock_resource *res);
 106static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
 107                                      struct dlm_lock_resource *res);
 108static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
 109                                       struct dlm_lock_resource *res,
 110                                       u8 target);
 111static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
 112                                       struct dlm_lock_resource *res);
 113
 114
 115int dlm_is_host_down(int errno)
 116{
 117        switch (errno) {
 118                case -EBADF:
 119                case -ECONNREFUSED:
 120                case -ENOTCONN:
 121                case -ECONNRESET:
 122                case -EPIPE:
 123                case -EHOSTDOWN:
 124                case -EHOSTUNREACH:
 125                case -ETIMEDOUT:
 126                case -ECONNABORTED:
 127                case -ENETDOWN:
 128                case -ENETUNREACH:
 129                case -ENETRESET:
 130                case -ESHUTDOWN:
 131                case -ENOPROTOOPT:
 132                case -EINVAL:   /* if returned from our tcp code,
 133                                   this means there is no socket */
 134                        return 1;
 135        }
 136        return 0;
 137}
 138
 139
 140/*
 141 * MASTER LIST FUNCTIONS
 142 */
 143
 144
 145/*
 146 * regarding master list entries and heartbeat callbacks:
 147 *
 148 * in order to avoid sleeping and allocation that occurs in
 149 * heartbeat, master list entries are simply attached to the
 150 * dlm's established heartbeat callbacks.  the mle is attached
 151 * when it is created, and since the dlm->spinlock is held at
 152 * that time, any heartbeat event will be properly discovered
 153 * by the mle.  the mle needs to be detached from the
 154 * dlm->mle_hb_events list as soon as heartbeat events are no
 155 * longer useful to the mle, and before the mle is freed.
 156 *
 157 * as a general rule, heartbeat events are no longer needed by
 158 * the mle once an "answer" regarding the lock master has been
 159 * received.
 160 */
 161static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm,
 162                                              struct dlm_master_list_entry *mle)
 163{
 164        assert_spin_locked(&dlm->spinlock);
 165
 166        list_add_tail(&mle->hb_events, &dlm->mle_hb_events);
 167}
 168
 169
 170static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
 171                                              struct dlm_master_list_entry *mle)
 172{
 173        if (!list_empty(&mle->hb_events))
 174                list_del_init(&mle->hb_events);
 175}
 176
 177
 178static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm,
 179                                            struct dlm_master_list_entry *mle)
 180{
 181        spin_lock(&dlm->spinlock);
 182        __dlm_mle_detach_hb_events(dlm, mle);
 183        spin_unlock(&dlm->spinlock);
 184}
 185
 186static void dlm_get_mle_inuse(struct dlm_master_list_entry *mle)
 187{
 188        struct dlm_ctxt *dlm;
 189        dlm = mle->dlm;
 190
 191        assert_spin_locked(&dlm->spinlock);
 192        assert_spin_locked(&dlm->master_lock);
 193        mle->inuse++;
 194        kref_get(&mle->mle_refs);
 195}
 196
 197static void dlm_put_mle_inuse(struct dlm_master_list_entry *mle)
 198{
 199        struct dlm_ctxt *dlm;
 200        dlm = mle->dlm;
 201
 202        spin_lock(&dlm->spinlock);
 203        spin_lock(&dlm->master_lock);
 204        mle->inuse--;
 205        __dlm_put_mle(mle);
 206        spin_unlock(&dlm->master_lock);
 207        spin_unlock(&dlm->spinlock);
 208
 209}
 210
 211/* remove from list and free */
 212static void __dlm_put_mle(struct dlm_master_list_entry *mle)
 213{
 214        struct dlm_ctxt *dlm;
 215        dlm = mle->dlm;
 216
 217        assert_spin_locked(&dlm->spinlock);
 218        assert_spin_locked(&dlm->master_lock);
 219        if (!kref_read(&mle->mle_refs)) {
 220                /* this may or may not crash, but who cares.
 221                 * it's a BUG. */
 222                mlog(ML_ERROR, "bad mle: %p\n", mle);
 223                dlm_print_one_mle(mle);
 224                BUG();
 225        } else
 226                kref_put(&mle->mle_refs, dlm_mle_release);
 227}
 228
 229
 230/* must not have any spinlocks coming in */
 231static void dlm_put_mle(struct dlm_master_list_entry *mle)
 232{
 233        struct dlm_ctxt *dlm;
 234        dlm = mle->dlm;
 235
 236        spin_lock(&dlm->spinlock);
 237        spin_lock(&dlm->master_lock);
 238        __dlm_put_mle(mle);
 239        spin_unlock(&dlm->master_lock);
 240        spin_unlock(&dlm->spinlock);
 241}
 242
 243static inline void dlm_get_mle(struct dlm_master_list_entry *mle)
 244{
 245        kref_get(&mle->mle_refs);
 246}
 247
 248static void dlm_init_mle(struct dlm_master_list_entry *mle,
 249                        enum dlm_mle_type type,
 250                        struct dlm_ctxt *dlm,
 251                        struct dlm_lock_resource *res,
 252                        const char *name,
 253                        unsigned int namelen)
 254{
 255        assert_spin_locked(&dlm->spinlock);
 256
 257        mle->dlm = dlm;
 258        mle->type = type;
 259        INIT_HLIST_NODE(&mle->master_hash_node);
 260        INIT_LIST_HEAD(&mle->hb_events);
 261        memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
 262        spin_lock_init(&mle->spinlock);
 263        init_waitqueue_head(&mle->wq);
 264        atomic_set(&mle->woken, 0);
 265        kref_init(&mle->mle_refs);
 266        memset(mle->response_map, 0, sizeof(mle->response_map));
 267        mle->master = O2NM_MAX_NODES;
 268        mle->new_master = O2NM_MAX_NODES;
 269        mle->inuse = 0;
 270
 271        BUG_ON(mle->type != DLM_MLE_BLOCK &&
 272               mle->type != DLM_MLE_MASTER &&
 273               mle->type != DLM_MLE_MIGRATION);
 274
 275        if (mle->type == DLM_MLE_MASTER) {
 276                BUG_ON(!res);
 277                mle->mleres = res;
 278                memcpy(mle->mname, res->lockname.name, res->lockname.len);
 279                mle->mnamelen = res->lockname.len;
 280                mle->mnamehash = res->lockname.hash;
 281        } else {
 282                BUG_ON(!name);
 283                mle->mleres = NULL;
 284                memcpy(mle->mname, name, namelen);
 285                mle->mnamelen = namelen;
 286                mle->mnamehash = dlm_lockid_hash(name, namelen);
 287        }
 288
 289        atomic_inc(&dlm->mle_tot_count[mle->type]);
 290        atomic_inc(&dlm->mle_cur_count[mle->type]);
 291
 292        /* copy off the node_map and register hb callbacks on our copy */
 293        memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map));
 294        memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map));
 295        clear_bit(dlm->node_num, mle->vote_map);
 296        clear_bit(dlm->node_num, mle->node_map);
 297
 298        /* attach the mle to the domain node up/down events */
 299        __dlm_mle_attach_hb_events(dlm, mle);
 300}
 301
 302void __dlm_unlink_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
 303{
 304        assert_spin_locked(&dlm->spinlock);
 305        assert_spin_locked(&dlm->master_lock);
 306
 307        if (!hlist_unhashed(&mle->master_hash_node))
 308                hlist_del_init(&mle->master_hash_node);
 309}
 310
 311void __dlm_insert_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle)
 312{
 313        struct hlist_head *bucket;
 314
 315        assert_spin_locked(&dlm->master_lock);
 316
 317        bucket = dlm_master_hash(dlm, mle->mnamehash);
 318        hlist_add_head(&mle->master_hash_node, bucket);
 319}
 320
 321/* returns 1 if found, 0 if not */
 322static int dlm_find_mle(struct dlm_ctxt *dlm,
 323                        struct dlm_master_list_entry **mle,
 324                        char *name, unsigned int namelen)
 325{
 326        struct dlm_master_list_entry *tmpmle;
 327        struct hlist_head *bucket;
 328        unsigned int hash;
 329
 330        assert_spin_locked(&dlm->master_lock);
 331
 332        hash = dlm_lockid_hash(name, namelen);
 333        bucket = dlm_master_hash(dlm, hash);
 334        hlist_for_each_entry(tmpmle, bucket, master_hash_node) {
 335                if (!dlm_mle_equal(dlm, tmpmle, name, namelen))
 336                        continue;
 337                dlm_get_mle(tmpmle);
 338                *mle = tmpmle;
 339                return 1;
 340        }
 341        return 0;
 342}
 343
 344void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up)
 345{
 346        struct dlm_master_list_entry *mle;
 347
 348        assert_spin_locked(&dlm->spinlock);
 349
 350        list_for_each_entry(mle, &dlm->mle_hb_events, hb_events) {
 351                if (node_up)
 352                        dlm_mle_node_up(dlm, mle, NULL, idx);
 353                else
 354                        dlm_mle_node_down(dlm, mle, NULL, idx);
 355        }
 356}
 357
 358static void dlm_mle_node_down(struct dlm_ctxt *dlm,
 359                              struct dlm_master_list_entry *mle,
 360                              struct o2nm_node *node, int idx)
 361{
 362        spin_lock(&mle->spinlock);
 363
 364        if (!test_bit(idx, mle->node_map))
 365                mlog(0, "node %u already removed from nodemap!\n", idx);
 366        else
 367                clear_bit(idx, mle->node_map);
 368
 369        spin_unlock(&mle->spinlock);
 370}
 371
 372static void dlm_mle_node_up(struct dlm_ctxt *dlm,
 373                            struct dlm_master_list_entry *mle,
 374                            struct o2nm_node *node, int idx)
 375{
 376        spin_lock(&mle->spinlock);
 377
 378        if (test_bit(idx, mle->node_map))
 379                mlog(0, "node %u already in node map!\n", idx);
 380        else
 381                set_bit(idx, mle->node_map);
 382
 383        spin_unlock(&mle->spinlock);
 384}
 385
 386
 387int dlm_init_mle_cache(void)
 388{
 389        dlm_mle_cache = kmem_cache_create("o2dlm_mle",
 390                                          sizeof(struct dlm_master_list_entry),
 391                                          0, SLAB_HWCACHE_ALIGN,
 392                                          NULL);
 393        if (dlm_mle_cache == NULL)
 394                return -ENOMEM;
 395        return 0;
 396}
 397
 398void dlm_destroy_mle_cache(void)
 399{
 400        kmem_cache_destroy(dlm_mle_cache);
 401}
 402
 403static void dlm_mle_release(struct kref *kref)
 404{
 405        struct dlm_master_list_entry *mle;
 406        struct dlm_ctxt *dlm;
 407
 408        mle = container_of(kref, struct dlm_master_list_entry, mle_refs);
 409        dlm = mle->dlm;
 410
 411        assert_spin_locked(&dlm->spinlock);
 412        assert_spin_locked(&dlm->master_lock);
 413
 414        mlog(0, "Releasing mle for %.*s, type %d\n", mle->mnamelen, mle->mname,
 415             mle->type);
 416
 417        /* remove from list if not already */
 418        __dlm_unlink_mle(dlm, mle);
 419
 420        /* detach the mle from the domain node up/down events */
 421        __dlm_mle_detach_hb_events(dlm, mle);
 422
 423        atomic_dec(&dlm->mle_cur_count[mle->type]);
 424
 425        /* NOTE: kfree under spinlock here.
 426         * if this is bad, we can move this to a freelist. */
 427        kmem_cache_free(dlm_mle_cache, mle);
 428}
 429
 430
 431/*
 432 * LOCK RESOURCE FUNCTIONS
 433 */
 434
 435int dlm_init_master_caches(void)
 436{
 437        dlm_lockres_cache = kmem_cache_create("o2dlm_lockres",
 438                                              sizeof(struct dlm_lock_resource),
 439                                              0, SLAB_HWCACHE_ALIGN, NULL);
 440        if (!dlm_lockres_cache)
 441                goto bail;
 442
 443        dlm_lockname_cache = kmem_cache_create("o2dlm_lockname",
 444                                               DLM_LOCKID_NAME_MAX, 0,
 445                                               SLAB_HWCACHE_ALIGN, NULL);
 446        if (!dlm_lockname_cache)
 447                goto bail;
 448
 449        return 0;
 450bail:
 451        dlm_destroy_master_caches();
 452        return -ENOMEM;
 453}
 454
 455void dlm_destroy_master_caches(void)
 456{
 457        kmem_cache_destroy(dlm_lockname_cache);
 458        dlm_lockname_cache = NULL;
 459
 460        kmem_cache_destroy(dlm_lockres_cache);
 461        dlm_lockres_cache = NULL;
 462}
 463
 464static void dlm_lockres_release(struct kref *kref)
 465{
 466        struct dlm_lock_resource *res;
 467        struct dlm_ctxt *dlm;
 468
 469        res = container_of(kref, struct dlm_lock_resource, refs);
 470        dlm = res->dlm;
 471
 472        /* This should not happen -- all lockres' have a name
 473         * associated with them at init time. */
 474        BUG_ON(!res->lockname.name);
 475
 476        mlog(0, "destroying lockres %.*s\n", res->lockname.len,
 477             res->lockname.name);
 478
 479        atomic_dec(&dlm->res_cur_count);
 480
 481        if (!hlist_unhashed(&res->hash_node) ||
 482            !list_empty(&res->granted) ||
 483            !list_empty(&res->converting) ||
 484            !list_empty(&res->blocked) ||
 485            !list_empty(&res->dirty) ||
 486            !list_empty(&res->recovering) ||
 487            !list_empty(&res->purge)) {
 488                mlog(ML_ERROR,
 489                     "Going to BUG for resource %.*s."
 490                     "  We're on a list! [%c%c%c%c%c%c%c]\n",
 491                     res->lockname.len, res->lockname.name,
 492                     !hlist_unhashed(&res->hash_node) ? 'H' : ' ',
 493                     !list_empty(&res->granted) ? 'G' : ' ',
 494                     !list_empty(&res->converting) ? 'C' : ' ',
 495                     !list_empty(&res->blocked) ? 'B' : ' ',
 496                     !list_empty(&res->dirty) ? 'D' : ' ',
 497                     !list_empty(&res->recovering) ? 'R' : ' ',
 498                     !list_empty(&res->purge) ? 'P' : ' ');
 499
 500                dlm_print_one_lock_resource(res);
 501        }
 502
 503        /* By the time we're ready to blow this guy away, we shouldn't
 504         * be on any lists. */
 505        BUG_ON(!hlist_unhashed(&res->hash_node));
 506        BUG_ON(!list_empty(&res->granted));
 507        BUG_ON(!list_empty(&res->converting));
 508        BUG_ON(!list_empty(&res->blocked));
 509        BUG_ON(!list_empty(&res->dirty));
 510        BUG_ON(!list_empty(&res->recovering));
 511        BUG_ON(!list_empty(&res->purge));
 512
 513        kmem_cache_free(dlm_lockname_cache, (void *)res->lockname.name);
 514
 515        kmem_cache_free(dlm_lockres_cache, res);
 516}
 517
 518void dlm_lockres_put(struct dlm_lock_resource *res)
 519{
 520        kref_put(&res->refs, dlm_lockres_release);
 521}
 522
 523static void dlm_init_lockres(struct dlm_ctxt *dlm,
 524                             struct dlm_lock_resource *res,
 525                             const char *name, unsigned int namelen)
 526{
 527        char *qname;
 528
 529        /* If we memset here, we lose our reference to the kmalloc'd
 530         * res->lockname.name, so be sure to init every field
 531         * correctly! */
 532
 533        qname = (char *) res->lockname.name;
 534        memcpy(qname, name, namelen);
 535
 536        res->lockname.len = namelen;
 537        res->lockname.hash = dlm_lockid_hash(name, namelen);
 538
 539        init_waitqueue_head(&res->wq);
 540        spin_lock_init(&res->spinlock);
 541        INIT_HLIST_NODE(&res->hash_node);
 542        INIT_LIST_HEAD(&res->granted);
 543        INIT_LIST_HEAD(&res->converting);
 544        INIT_LIST_HEAD(&res->blocked);
 545        INIT_LIST_HEAD(&res->dirty);
 546        INIT_LIST_HEAD(&res->recovering);
 547        INIT_LIST_HEAD(&res->purge);
 548        INIT_LIST_HEAD(&res->tracking);
 549        atomic_set(&res->asts_reserved, 0);
 550        res->migration_pending = 0;
 551        res->inflight_locks = 0;
 552        res->inflight_assert_workers = 0;
 553
 554        res->dlm = dlm;
 555
 556        kref_init(&res->refs);
 557
 558        atomic_inc(&dlm->res_tot_count);
 559        atomic_inc(&dlm->res_cur_count);
 560
 561        /* just for consistency */
 562        spin_lock(&res->spinlock);
 563        dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
 564        spin_unlock(&res->spinlock);
 565
 566        res->state = DLM_LOCK_RES_IN_PROGRESS;
 567
 568        res->last_used = 0;
 569
 570        spin_lock(&dlm->track_lock);
 571        list_add_tail(&res->tracking, &dlm->tracking_list);
 572        spin_unlock(&dlm->track_lock);
 573
 574        memset(res->lvb, 0, DLM_LVB_LEN);
 575        memset(res->refmap, 0, sizeof(res->refmap));
 576}
 577
 578struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm,
 579                                   const char *name,
 580                                   unsigned int namelen)
 581{
 582        struct dlm_lock_resource *res = NULL;
 583
 584        res = kmem_cache_zalloc(dlm_lockres_cache, GFP_NOFS);
 585        if (!res)
 586                goto error;
 587
 588        res->lockname.name = kmem_cache_zalloc(dlm_lockname_cache, GFP_NOFS);
 589        if (!res->lockname.name)
 590                goto error;
 591
 592        dlm_init_lockres(dlm, res, name, namelen);
 593        return res;
 594
 595error:
 596        if (res)
 597                kmem_cache_free(dlm_lockres_cache, res);
 598        return NULL;
 599}
 600
 601void dlm_lockres_set_refmap_bit(struct dlm_ctxt *dlm,
 602                                struct dlm_lock_resource *res, int bit)
 603{
 604        assert_spin_locked(&res->spinlock);
 605
 606        mlog(0, "res %.*s, set node %u, %ps()\n", res->lockname.len,
 607             res->lockname.name, bit, __builtin_return_address(0));
 608
 609        set_bit(bit, res->refmap);
 610}
 611
 612void dlm_lockres_clear_refmap_bit(struct dlm_ctxt *dlm,
 613                                  struct dlm_lock_resource *res, int bit)
 614{
 615        assert_spin_locked(&res->spinlock);
 616
 617        mlog(0, "res %.*s, clr node %u, %ps()\n", res->lockname.len,
 618             res->lockname.name, bit, __builtin_return_address(0));
 619
 620        clear_bit(bit, res->refmap);
 621}
 622
 623static void __dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
 624                                   struct dlm_lock_resource *res)
 625{
 626        res->inflight_locks++;
 627
 628        mlog(0, "%s: res %.*s, inflight++: now %u, %ps()\n", dlm->name,
 629             res->lockname.len, res->lockname.name, res->inflight_locks,
 630             __builtin_return_address(0));
 631}
 632
 633void dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm,
 634                                   struct dlm_lock_resource *res)
 635{
 636        assert_spin_locked(&res->spinlock);
 637        __dlm_lockres_grab_inflight_ref(dlm, res);
 638}
 639
 640void dlm_lockres_drop_inflight_ref(struct dlm_ctxt *dlm,
 641                                   struct dlm_lock_resource *res)
 642{
 643        assert_spin_locked(&res->spinlock);
 644
 645        BUG_ON(res->inflight_locks == 0);
 646
 647        res->inflight_locks--;
 648
 649        mlog(0, "%s: res %.*s, inflight--: now %u, %ps()\n", dlm->name,
 650             res->lockname.len, res->lockname.name, res->inflight_locks,
 651             __builtin_return_address(0));
 652
 653        wake_up(&res->wq);
 654}
 655
 656void __dlm_lockres_grab_inflight_worker(struct dlm_ctxt *dlm,
 657                struct dlm_lock_resource *res)
 658{
 659        assert_spin_locked(&res->spinlock);
 660        res->inflight_assert_workers++;
 661        mlog(0, "%s:%.*s: inflight assert worker++: now %u\n",
 662                        dlm->name, res->lockname.len, res->lockname.name,
 663                        res->inflight_assert_workers);
 664}
 665
 666static void __dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm,
 667                struct dlm_lock_resource *res)
 668{
 669        assert_spin_locked(&res->spinlock);
 670        BUG_ON(res->inflight_assert_workers == 0);
 671        res->inflight_assert_workers--;
 672        mlog(0, "%s:%.*s: inflight assert worker--: now %u\n",
 673                        dlm->name, res->lockname.len, res->lockname.name,
 674                        res->inflight_assert_workers);
 675}
 676
 677static void dlm_lockres_drop_inflight_worker(struct dlm_ctxt *dlm,
 678                struct dlm_lock_resource *res)
 679{
 680        spin_lock(&res->spinlock);
 681        __dlm_lockres_drop_inflight_worker(dlm, res);
 682        spin_unlock(&res->spinlock);
 683}
 684
 685/*
 686 * lookup a lock resource by name.
 687 * may already exist in the hashtable.
 688 * lockid is null terminated
 689 *
 690 * if not, allocate enough for the lockres and for
 691 * the temporary structure used in doing the mastering.
 692 *
 693 * also, do a lookup in the dlm->master_list to see
 694 * if another node has begun mastering the same lock.
 695 * if so, there should be a block entry in there
 696 * for this name, and we should *not* attempt to master
 697 * the lock here.   need to wait around for that node
 698 * to assert_master (or die).
 699 *
 700 */
 701struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm,
 702                                          const char *lockid,
 703                                          int namelen,
 704                                          int flags)
 705{
 706        struct dlm_lock_resource *tmpres=NULL, *res=NULL;
 707        struct dlm_master_list_entry *mle = NULL;
 708        struct dlm_master_list_entry *alloc_mle = NULL;
 709        int blocked = 0;
 710        int ret, nodenum;
 711        struct dlm_node_iter iter;
 712        unsigned int hash;
 713        int tries = 0;
 714        int bit, wait_on_recovery = 0;
 715
 716        BUG_ON(!lockid);
 717
 718        hash = dlm_lockid_hash(lockid, namelen);
 719
 720        mlog(0, "get lockres %s (len %d)\n", lockid, namelen);
 721
 722lookup:
 723        spin_lock(&dlm->spinlock);
 724        tmpres = __dlm_lookup_lockres_full(dlm, lockid, namelen, hash);
 725        if (tmpres) {
 726                spin_unlock(&dlm->spinlock);
 727                spin_lock(&tmpres->spinlock);
 728
 729                /*
 730                 * Right after dlm spinlock was released, dlm_thread could have
 731                 * purged the lockres. Check if lockres got unhashed. If so
 732                 * start over.
 733                 */
 734                if (hlist_unhashed(&tmpres->hash_node)) {
 735                        spin_unlock(&tmpres->spinlock);
 736                        dlm_lockres_put(tmpres);
 737                        tmpres = NULL;
 738                        goto lookup;
 739                }
 740
 741                /* Wait on the thread that is mastering the resource */
 742                if (tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN) {
 743                        __dlm_wait_on_lockres(tmpres);
 744                        BUG_ON(tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN);
 745                        spin_unlock(&tmpres->spinlock);
 746                        dlm_lockres_put(tmpres);
 747                        tmpres = NULL;
 748                        goto lookup;
 749                }
 750
 751                /* Wait on the resource purge to complete before continuing */
 752                if (tmpres->state & DLM_LOCK_RES_DROPPING_REF) {
 753                        BUG_ON(tmpres->owner == dlm->node_num);
 754                        __dlm_wait_on_lockres_flags(tmpres,
 755                                                    DLM_LOCK_RES_DROPPING_REF);
 756                        spin_unlock(&tmpres->spinlock);
 757                        dlm_lockres_put(tmpres);
 758                        tmpres = NULL;
 759                        goto lookup;
 760                }
 761
 762                /* Grab inflight ref to pin the resource */
 763                dlm_lockres_grab_inflight_ref(dlm, tmpres);
 764
 765                spin_unlock(&tmpres->spinlock);
 766                if (res) {
 767                        spin_lock(&dlm->track_lock);
 768                        if (!list_empty(&res->tracking))
 769                                list_del_init(&res->tracking);
 770                        else
 771                                mlog(ML_ERROR, "Resource %.*s not "
 772                                                "on the Tracking list\n",
 773                                                res->lockname.len,
 774                                                res->lockname.name);
 775                        spin_unlock(&dlm->track_lock);
 776                        dlm_lockres_put(res);
 777                }
 778                res = tmpres;
 779                goto leave;
 780        }
 781
 782        if (!res) {
 783                spin_unlock(&dlm->spinlock);
 784                mlog(0, "allocating a new resource\n");
 785                /* nothing found and we need to allocate one. */
 786                alloc_mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
 787                if (!alloc_mle)
 788                        goto leave;
 789                res = dlm_new_lockres(dlm, lockid, namelen);
 790                if (!res)
 791                        goto leave;
 792                goto lookup;
 793        }
 794
 795        mlog(0, "no lockres found, allocated our own: %p\n", res);
 796
 797        if (flags & LKM_LOCAL) {
 798                /* caller knows it's safe to assume it's not mastered elsewhere
 799                 * DONE!  return right away */
 800                spin_lock(&res->spinlock);
 801                dlm_change_lockres_owner(dlm, res, dlm->node_num);
 802                __dlm_insert_lockres(dlm, res);
 803                dlm_lockres_grab_inflight_ref(dlm, res);
 804                spin_unlock(&res->spinlock);
 805                spin_unlock(&dlm->spinlock);
 806                /* lockres still marked IN_PROGRESS */
 807                goto wake_waiters;
 808        }
 809
 810        /* check master list to see if another node has started mastering it */
 811        spin_lock(&dlm->master_lock);
 812
 813        /* if we found a block, wait for lock to be mastered by another node */
 814        blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen);
 815        if (blocked) {
 816                int mig;
 817                if (mle->type == DLM_MLE_MASTER) {
 818                        mlog(ML_ERROR, "master entry for nonexistent lock!\n");
 819                        BUG();
 820                }
 821                mig = (mle->type == DLM_MLE_MIGRATION);
 822                /* if there is a migration in progress, let the migration
 823                 * finish before continuing.  we can wait for the absence
 824                 * of the MIGRATION mle: either the migrate finished or
 825                 * one of the nodes died and the mle was cleaned up.
 826                 * if there is a BLOCK here, but it already has a master
 827                 * set, we are too late.  the master does not have a ref
 828                 * for us in the refmap.  detach the mle and drop it.
 829                 * either way, go back to the top and start over. */
 830                if (mig || mle->master != O2NM_MAX_NODES) {
 831                        BUG_ON(mig && mle->master == dlm->node_num);
 832                        /* we arrived too late.  the master does not
 833                         * have a ref for us. retry. */
 834                        mlog(0, "%s:%.*s: late on %s\n",
 835                             dlm->name, namelen, lockid,
 836                             mig ?  "MIGRATION" : "BLOCK");
 837                        spin_unlock(&dlm->master_lock);
 838                        spin_unlock(&dlm->spinlock);
 839
 840                        /* master is known, detach */
 841                        if (!mig)
 842                                dlm_mle_detach_hb_events(dlm, mle);
 843                        dlm_put_mle(mle);
 844                        mle = NULL;
 845                        /* this is lame, but we can't wait on either
 846                         * the mle or lockres waitqueue here */
 847                        if (mig)
 848                                msleep(100);
 849                        goto lookup;
 850                }
 851        } else {
 852                /* go ahead and try to master lock on this node */
 853                mle = alloc_mle;
 854                /* make sure this does not get freed below */
 855                alloc_mle = NULL;
 856                dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0);
 857                set_bit(dlm->node_num, mle->maybe_map);
 858                __dlm_insert_mle(dlm, mle);
 859
 860                /* still holding the dlm spinlock, check the recovery map
 861                 * to see if there are any nodes that still need to be
 862                 * considered.  these will not appear in the mle nodemap
 863                 * but they might own this lockres.  wait on them. */
 864                bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
 865                if (bit < O2NM_MAX_NODES) {
 866                        mlog(0, "%s: res %.*s, At least one node (%d) "
 867                             "to recover before lock mastery can begin\n",
 868                             dlm->name, namelen, (char *)lockid, bit);
 869                        wait_on_recovery = 1;
 870                }
 871        }
 872
 873        /* at this point there is either a DLM_MLE_BLOCK or a
 874         * DLM_MLE_MASTER on the master list, so it's safe to add the
 875         * lockres to the hashtable.  anyone who finds the lock will
 876         * still have to wait on the IN_PROGRESS. */
 877
 878        /* finally add the lockres to its hash bucket */
 879        __dlm_insert_lockres(dlm, res);
 880
 881        /* since this lockres is new it doesn't not require the spinlock */
 882        __dlm_lockres_grab_inflight_ref(dlm, res);
 883
 884        /* get an extra ref on the mle in case this is a BLOCK
 885         * if so, the creator of the BLOCK may try to put the last
 886         * ref at this time in the assert master handler, so we
 887         * need an extra one to keep from a bad ptr deref. */
 888        dlm_get_mle_inuse(mle);
 889        spin_unlock(&dlm->master_lock);
 890        spin_unlock(&dlm->spinlock);
 891
 892redo_request:
 893        while (wait_on_recovery) {
 894                /* any cluster changes that occurred after dropping the
 895                 * dlm spinlock would be detectable be a change on the mle,
 896                 * so we only need to clear out the recovery map once. */
 897                if (dlm_is_recovery_lock(lockid, namelen)) {
 898                        mlog(0, "%s: Recovery map is not empty, but must "
 899                             "master $RECOVERY lock now\n", dlm->name);
 900                        if (!dlm_pre_master_reco_lockres(dlm, res))
 901                                wait_on_recovery = 0;
 902                        else {
 903                                mlog(0, "%s: waiting 500ms for heartbeat state "
 904                                    "change\n", dlm->name);
 905                                msleep(500);
 906                        }
 907                        continue;
 908                }
 909
 910                dlm_kick_recovery_thread(dlm);
 911                msleep(1000);
 912                dlm_wait_for_recovery(dlm);
 913
 914                spin_lock(&dlm->spinlock);
 915                bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0);
 916                if (bit < O2NM_MAX_NODES) {
 917                        mlog(0, "%s: res %.*s, At least one node (%d) "
 918                             "to recover before lock mastery can begin\n",
 919                             dlm->name, namelen, (char *)lockid, bit);
 920                        wait_on_recovery = 1;
 921                } else
 922                        wait_on_recovery = 0;
 923                spin_unlock(&dlm->spinlock);
 924
 925                if (wait_on_recovery)
 926                        dlm_wait_for_node_recovery(dlm, bit, 10000);
 927        }
 928
 929        /* must wait for lock to be mastered elsewhere */
 930        if (blocked)
 931                goto wait;
 932
 933        ret = -EINVAL;
 934        dlm_node_iter_init(mle->vote_map, &iter);
 935        while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
 936                ret = dlm_do_master_request(res, mle, nodenum);
 937                if (ret < 0)
 938                        mlog_errno(ret);
 939                if (mle->master != O2NM_MAX_NODES) {
 940                        /* found a master ! */
 941                        if (mle->master <= nodenum)
 942                                break;
 943                        /* if our master request has not reached the master
 944                         * yet, keep going until it does.  this is how the
 945                         * master will know that asserts are needed back to
 946                         * the lower nodes. */
 947                        mlog(0, "%s: res %.*s, Requests only up to %u but "
 948                             "master is %u, keep going\n", dlm->name, namelen,
 949                             lockid, nodenum, mle->master);
 950                }
 951        }
 952
 953wait:
 954        /* keep going until the response map includes all nodes */
 955        ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked);
 956        if (ret < 0) {
 957                wait_on_recovery = 1;
 958                mlog(0, "%s: res %.*s, Node map changed, redo the master "
 959                     "request now, blocked=%d\n", dlm->name, res->lockname.len,
 960                     res->lockname.name, blocked);
 961                if (++tries > 20) {
 962                        mlog(ML_ERROR, "%s: res %.*s, Spinning on "
 963                             "dlm_wait_for_lock_mastery, blocked = %d\n",
 964                             dlm->name, res->lockname.len,
 965                             res->lockname.name, blocked);
 966                        dlm_print_one_lock_resource(res);
 967                        dlm_print_one_mle(mle);
 968                        tries = 0;
 969                }
 970                goto redo_request;
 971        }
 972
 973        mlog(0, "%s: res %.*s, Mastered by %u\n", dlm->name, res->lockname.len,
 974             res->lockname.name, res->owner);
 975        /* make sure we never continue without this */
 976        BUG_ON(res->owner == O2NM_MAX_NODES);
 977
 978        /* master is known, detach if not already detached */
 979        dlm_mle_detach_hb_events(dlm, mle);
 980        dlm_put_mle(mle);
 981        /* put the extra ref */
 982        dlm_put_mle_inuse(mle);
 983
 984wake_waiters:
 985        spin_lock(&res->spinlock);
 986        res->state &= ~DLM_LOCK_RES_IN_PROGRESS;
 987        spin_unlock(&res->spinlock);
 988        wake_up(&res->wq);
 989
 990leave:
 991        /* need to free the unused mle */
 992        if (alloc_mle)
 993                kmem_cache_free(dlm_mle_cache, alloc_mle);
 994
 995        return res;
 996}
 997
 998
 999#define DLM_MASTERY_TIMEOUT_MS   5000
1000
1001static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm,
1002                                     struct dlm_lock_resource *res,
1003                                     struct dlm_master_list_entry *mle,
1004                                     int *blocked)
1005{
1006        u8 m;
1007        int ret, bit;
1008        int map_changed, voting_done;
1009        int assert, sleep;
1010
1011recheck:
1012        ret = 0;
1013        assert = 0;
1014
1015        /* check if another node has already become the owner */
1016        spin_lock(&res->spinlock);
1017        if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1018                mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name,
1019                     res->lockname.len, res->lockname.name, res->owner);
1020                spin_unlock(&res->spinlock);
1021                /* this will cause the master to re-assert across
1022                 * the whole cluster, freeing up mles */
1023                if (res->owner != dlm->node_num) {
1024                        ret = dlm_do_master_request(res, mle, res->owner);
1025                        if (ret < 0) {
1026                                /* give recovery a chance to run */
1027                                mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret);
1028                                msleep(500);
1029                                goto recheck;
1030                        }
1031                }
1032                ret = 0;
1033                goto leave;
1034        }
1035        spin_unlock(&res->spinlock);
1036
1037        spin_lock(&mle->spinlock);
1038        m = mle->master;
1039        map_changed = (memcmp(mle->vote_map, mle->node_map,
1040                              sizeof(mle->vote_map)) != 0);
1041        voting_done = (memcmp(mle->vote_map, mle->response_map,
1042                             sizeof(mle->vote_map)) == 0);
1043
1044        /* restart if we hit any errors */
1045        if (map_changed) {
1046                int b;
1047                mlog(0, "%s: %.*s: node map changed, restarting\n",
1048                     dlm->name, res->lockname.len, res->lockname.name);
1049                ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked);
1050                b = (mle->type == DLM_MLE_BLOCK);
1051                if ((*blocked && !b) || (!*blocked && b)) {
1052                        mlog(0, "%s:%.*s: status change: old=%d new=%d\n",
1053                             dlm->name, res->lockname.len, res->lockname.name,
1054                             *blocked, b);
1055                        *blocked = b;
1056                }
1057                spin_unlock(&mle->spinlock);
1058                if (ret < 0) {
1059                        mlog_errno(ret);
1060                        goto leave;
1061                }
1062                mlog(0, "%s:%.*s: restart lock mastery succeeded, "
1063                     "rechecking now\n", dlm->name, res->lockname.len,
1064                     res->lockname.name);
1065                goto recheck;
1066        } else {
1067                if (!voting_done) {
1068                        mlog(0, "map not changed and voting not done "
1069                             "for %s:%.*s\n", dlm->name, res->lockname.len,
1070                             res->lockname.name);
1071                }
1072        }
1073
1074        if (m != O2NM_MAX_NODES) {
1075                /* another node has done an assert!
1076                 * all done! */
1077                sleep = 0;
1078        } else {
1079                sleep = 1;
1080                /* have all nodes responded? */
1081                if (voting_done && !*blocked) {
1082                        bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
1083                        if (dlm->node_num <= bit) {
1084                                /* my node number is lowest.
1085                                 * now tell other nodes that I am
1086                                 * mastering this. */
1087                                mle->master = dlm->node_num;
1088                                /* ref was grabbed in get_lock_resource
1089                                 * will be dropped in dlmlock_master */
1090                                assert = 1;
1091                                sleep = 0;
1092                        }
1093                        /* if voting is done, but we have not received
1094                         * an assert master yet, we must sleep */
1095                }
1096        }
1097
1098        spin_unlock(&mle->spinlock);
1099
1100        /* sleep if we haven't finished voting yet */
1101        if (sleep) {
1102                unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS);
1103                atomic_set(&mle->woken, 0);
1104                (void)wait_event_timeout(mle->wq,
1105                                         (atomic_read(&mle->woken) == 1),
1106                                         timeo);
1107                if (res->owner == O2NM_MAX_NODES) {
1108                        mlog(0, "%s:%.*s: waiting again\n", dlm->name,
1109                             res->lockname.len, res->lockname.name);
1110                        goto recheck;
1111                }
1112                mlog(0, "done waiting, master is %u\n", res->owner);
1113                ret = 0;
1114                goto leave;
1115        }
1116
1117        ret = 0;   /* done */
1118        if (assert) {
1119                m = dlm->node_num;
1120                mlog(0, "about to master %.*s here, this=%u\n",
1121                     res->lockname.len, res->lockname.name, m);
1122                ret = dlm_do_assert_master(dlm, res, mle->vote_map, 0);
1123                if (ret) {
1124                        /* This is a failure in the network path,
1125                         * not in the response to the assert_master
1126                         * (any nonzero response is a BUG on this node).
1127                         * Most likely a socket just got disconnected
1128                         * due to node death. */
1129                        mlog_errno(ret);
1130                }
1131                /* no longer need to restart lock mastery.
1132                 * all living nodes have been contacted. */
1133                ret = 0;
1134        }
1135
1136        /* set the lockres owner */
1137        spin_lock(&res->spinlock);
1138        /* mastery reference obtained either during
1139         * assert_master_handler or in get_lock_resource */
1140        dlm_change_lockres_owner(dlm, res, m);
1141        spin_unlock(&res->spinlock);
1142
1143leave:
1144        return ret;
1145}
1146
1147struct dlm_bitmap_diff_iter
1148{
1149        int curnode;
1150        unsigned long *orig_bm;
1151        unsigned long *cur_bm;
1152        unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)];
1153};
1154
1155enum dlm_node_state_change
1156{
1157        NODE_DOWN = -1,
1158        NODE_NO_CHANGE = 0,
1159        NODE_UP
1160};
1161
1162static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter,
1163                                      unsigned long *orig_bm,
1164                                      unsigned long *cur_bm)
1165{
1166        unsigned long p1, p2;
1167        int i;
1168
1169        iter->curnode = -1;
1170        iter->orig_bm = orig_bm;
1171        iter->cur_bm = cur_bm;
1172
1173        for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) {
1174                p1 = *(iter->orig_bm + i);
1175                p2 = *(iter->cur_bm + i);
1176                iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1);
1177        }
1178}
1179
1180static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter,
1181                                     enum dlm_node_state_change *state)
1182{
1183        int bit;
1184
1185        if (iter->curnode >= O2NM_MAX_NODES)
1186                return -ENOENT;
1187
1188        bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES,
1189                            iter->curnode+1);
1190        if (bit >= O2NM_MAX_NODES) {
1191                iter->curnode = O2NM_MAX_NODES;
1192                return -ENOENT;
1193        }
1194
1195        /* if it was there in the original then this node died */
1196        if (test_bit(bit, iter->orig_bm))
1197                *state = NODE_DOWN;
1198        else
1199                *state = NODE_UP;
1200
1201        iter->curnode = bit;
1202        return bit;
1203}
1204
1205
1206static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm,
1207                                    struct dlm_lock_resource *res,
1208                                    struct dlm_master_list_entry *mle,
1209                                    int blocked)
1210{
1211        struct dlm_bitmap_diff_iter bdi;
1212        enum dlm_node_state_change sc;
1213        int node;
1214        int ret = 0;
1215
1216        mlog(0, "something happened such that the "
1217             "master process may need to be restarted!\n");
1218
1219        assert_spin_locked(&mle->spinlock);
1220
1221        dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map);
1222        node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1223        while (node >= 0) {
1224                if (sc == NODE_UP) {
1225                        /* a node came up.  clear any old vote from
1226                         * the response map and set it in the vote map
1227                         * then restart the mastery. */
1228                        mlog(ML_NOTICE, "node %d up while restarting\n", node);
1229
1230                        /* redo the master request, but only for the new node */
1231                        mlog(0, "sending request to new node\n");
1232                        clear_bit(node, mle->response_map);
1233                        set_bit(node, mle->vote_map);
1234                } else {
1235                        mlog(ML_ERROR, "node down! %d\n", node);
1236                        if (blocked) {
1237                                int lowest = find_next_bit(mle->maybe_map,
1238                                                       O2NM_MAX_NODES, 0);
1239
1240                                /* act like it was never there */
1241                                clear_bit(node, mle->maybe_map);
1242
1243                                if (node == lowest) {
1244                                        mlog(0, "expected master %u died"
1245                                            " while this node was blocked "
1246                                            "waiting on it!\n", node);
1247                                        lowest = find_next_bit(mle->maybe_map,
1248                                                        O2NM_MAX_NODES,
1249                                                        lowest+1);
1250                                        if (lowest < O2NM_MAX_NODES) {
1251                                                mlog(0, "%s:%.*s:still "
1252                                                     "blocked. waiting on %u "
1253                                                     "now\n", dlm->name,
1254                                                     res->lockname.len,
1255                                                     res->lockname.name,
1256                                                     lowest);
1257                                        } else {
1258                                                /* mle is an MLE_BLOCK, but
1259                                                 * there is now nothing left to
1260                                                 * block on.  we need to return
1261                                                 * all the way back out and try
1262                                                 * again with an MLE_MASTER.
1263                                                 * dlm_do_local_recovery_cleanup
1264                                                 * has already run, so the mle
1265                                                 * refcount is ok */
1266                                                mlog(0, "%s:%.*s: no "
1267                                                     "longer blocking. try to "
1268                                                     "master this here\n",
1269                                                     dlm->name,
1270                                                     res->lockname.len,
1271                                                     res->lockname.name);
1272                                                mle->type = DLM_MLE_MASTER;
1273                                                mle->mleres = res;
1274                                        }
1275                                }
1276                        }
1277
1278                        /* now blank out everything, as if we had never
1279                         * contacted anyone */
1280                        memset(mle->maybe_map, 0, sizeof(mle->maybe_map));
1281                        memset(mle->response_map, 0, sizeof(mle->response_map));
1282                        /* reset the vote_map to the current node_map */
1283                        memcpy(mle->vote_map, mle->node_map,
1284                               sizeof(mle->node_map));
1285                        /* put myself into the maybe map */
1286                        if (mle->type != DLM_MLE_BLOCK)
1287                                set_bit(dlm->node_num, mle->maybe_map);
1288                }
1289                ret = -EAGAIN;
1290                node = dlm_bitmap_diff_iter_next(&bdi, &sc);
1291        }
1292        return ret;
1293}
1294
1295
1296/*
1297 * DLM_MASTER_REQUEST_MSG
1298 *
1299 * returns: 0 on success,
1300 *          -errno on a network error
1301 *
1302 * on error, the caller should assume the target node is "dead"
1303 *
1304 */
1305
1306static int dlm_do_master_request(struct dlm_lock_resource *res,
1307                                 struct dlm_master_list_entry *mle, int to)
1308{
1309        struct dlm_ctxt *dlm = mle->dlm;
1310        struct dlm_master_request request;
1311        int ret, response=0, resend;
1312
1313        memset(&request, 0, sizeof(request));
1314        request.node_idx = dlm->node_num;
1315
1316        BUG_ON(mle->type == DLM_MLE_MIGRATION);
1317
1318        request.namelen = (u8)mle->mnamelen;
1319        memcpy(request.name, mle->mname, request.namelen);
1320
1321again:
1322        ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request,
1323                                 sizeof(request), to, &response);
1324        if (ret < 0)  {
1325                if (ret == -ESRCH) {
1326                        /* should never happen */
1327                        mlog(ML_ERROR, "TCP stack not ready!\n");
1328                        BUG();
1329                } else if (ret == -EINVAL) {
1330                        mlog(ML_ERROR, "bad args passed to o2net!\n");
1331                        BUG();
1332                } else if (ret == -ENOMEM) {
1333                        mlog(ML_ERROR, "out of memory while trying to send "
1334                             "network message!  retrying\n");
1335                        /* this is totally crude */
1336                        msleep(50);
1337                        goto again;
1338                } else if (!dlm_is_host_down(ret)) {
1339                        /* not a network error. bad. */
1340                        mlog_errno(ret);
1341                        mlog(ML_ERROR, "unhandled error!");
1342                        BUG();
1343                }
1344                /* all other errors should be network errors,
1345                 * and likely indicate node death */
1346                mlog(ML_ERROR, "link to %d went down!\n", to);
1347                goto out;
1348        }
1349
1350        ret = 0;
1351        resend = 0;
1352        spin_lock(&mle->spinlock);
1353        switch (response) {
1354                case DLM_MASTER_RESP_YES:
1355                        set_bit(to, mle->response_map);
1356                        mlog(0, "node %u is the master, response=YES\n", to);
1357                        mlog(0, "%s:%.*s: master node %u now knows I have a "
1358                             "reference\n", dlm->name, res->lockname.len,
1359                             res->lockname.name, to);
1360                        mle->master = to;
1361                        break;
1362                case DLM_MASTER_RESP_NO:
1363                        mlog(0, "node %u not master, response=NO\n", to);
1364                        set_bit(to, mle->response_map);
1365                        break;
1366                case DLM_MASTER_RESP_MAYBE:
1367                        mlog(0, "node %u not master, response=MAYBE\n", to);
1368                        set_bit(to, mle->response_map);
1369                        set_bit(to, mle->maybe_map);
1370                        break;
1371                case DLM_MASTER_RESP_ERROR:
1372                        mlog(0, "node %u hit an error, resending\n", to);
1373                        resend = 1;
1374                        response = 0;
1375                        break;
1376                default:
1377                        mlog(ML_ERROR, "bad response! %u\n", response);
1378                        BUG();
1379        }
1380        spin_unlock(&mle->spinlock);
1381        if (resend) {
1382                /* this is also totally crude */
1383                msleep(50);
1384                goto again;
1385        }
1386
1387out:
1388        return ret;
1389}
1390
1391/*
1392 * locks that can be taken here:
1393 * dlm->spinlock
1394 * res->spinlock
1395 * mle->spinlock
1396 * dlm->master_list
1397 *
1398 * if possible, TRIM THIS DOWN!!!
1399 */
1400int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data,
1401                               void **ret_data)
1402{
1403        u8 response = DLM_MASTER_RESP_MAYBE;
1404        struct dlm_ctxt *dlm = data;
1405        struct dlm_lock_resource *res = NULL;
1406        struct dlm_master_request *request = (struct dlm_master_request *) msg->buf;
1407        struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL;
1408        char *name;
1409        unsigned int namelen, hash;
1410        int found, ret;
1411        int set_maybe;
1412        int dispatch_assert = 0;
1413        int dispatched = 0;
1414
1415        if (!dlm_grab(dlm))
1416                return DLM_MASTER_RESP_NO;
1417
1418        if (!dlm_domain_fully_joined(dlm)) {
1419                response = DLM_MASTER_RESP_NO;
1420                goto send_response;
1421        }
1422
1423        name = request->name;
1424        namelen = request->namelen;
1425        hash = dlm_lockid_hash(name, namelen);
1426
1427        if (namelen > DLM_LOCKID_NAME_MAX) {
1428                response = DLM_IVBUFLEN;
1429                goto send_response;
1430        }
1431
1432way_up_top:
1433        spin_lock(&dlm->spinlock);
1434        res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1435        if (res) {
1436                spin_unlock(&dlm->spinlock);
1437
1438                /* take care of the easy cases up front */
1439                spin_lock(&res->spinlock);
1440
1441                /*
1442                 * Right after dlm spinlock was released, dlm_thread could have
1443                 * purged the lockres. Check if lockres got unhashed. If so
1444                 * start over.
1445                 */
1446                if (hlist_unhashed(&res->hash_node)) {
1447                        spin_unlock(&res->spinlock);
1448                        dlm_lockres_put(res);
1449                        goto way_up_top;
1450                }
1451
1452                if (res->state & (DLM_LOCK_RES_RECOVERING|
1453                                  DLM_LOCK_RES_MIGRATING)) {
1454                        spin_unlock(&res->spinlock);
1455                        mlog(0, "returning DLM_MASTER_RESP_ERROR since res is "
1456                             "being recovered/migrated\n");
1457                        response = DLM_MASTER_RESP_ERROR;
1458                        if (mle)
1459                                kmem_cache_free(dlm_mle_cache, mle);
1460                        goto send_response;
1461                }
1462
1463                if (res->owner == dlm->node_num) {
1464                        dlm_lockres_set_refmap_bit(dlm, res, request->node_idx);
1465                        spin_unlock(&res->spinlock);
1466                        response = DLM_MASTER_RESP_YES;
1467                        if (mle)
1468                                kmem_cache_free(dlm_mle_cache, mle);
1469
1470                        /* this node is the owner.
1471                         * there is some extra work that needs to
1472                         * happen now.  the requesting node has
1473                         * caused all nodes up to this one to
1474                         * create mles.  this node now needs to
1475                         * go back and clean those up. */
1476                        dispatch_assert = 1;
1477                        goto send_response;
1478                } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1479                        spin_unlock(&res->spinlock);
1480                        // mlog(0, "node %u is the master\n", res->owner);
1481                        response = DLM_MASTER_RESP_NO;
1482                        if (mle)
1483                                kmem_cache_free(dlm_mle_cache, mle);
1484                        goto send_response;
1485                }
1486
1487                /* ok, there is no owner.  either this node is
1488                 * being blocked, or it is actively trying to
1489                 * master this lock. */
1490                if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1491                        mlog(ML_ERROR, "lock with no owner should be "
1492                             "in-progress!\n");
1493                        BUG();
1494                }
1495
1496                // mlog(0, "lockres is in progress...\n");
1497                spin_lock(&dlm->master_lock);
1498                found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1499                if (!found) {
1500                        mlog(ML_ERROR, "no mle found for this lock!\n");
1501                        BUG();
1502                }
1503                set_maybe = 1;
1504                spin_lock(&tmpmle->spinlock);
1505                if (tmpmle->type == DLM_MLE_BLOCK) {
1506                        // mlog(0, "this node is waiting for "
1507                        // "lockres to be mastered\n");
1508                        response = DLM_MASTER_RESP_NO;
1509                } else if (tmpmle->type == DLM_MLE_MIGRATION) {
1510                        mlog(0, "node %u is master, but trying to migrate to "
1511                             "node %u.\n", tmpmle->master, tmpmle->new_master);
1512                        if (tmpmle->master == dlm->node_num) {
1513                                mlog(ML_ERROR, "no owner on lockres, but this "
1514                                     "node is trying to migrate it to %u?!\n",
1515                                     tmpmle->new_master);
1516                                BUG();
1517                        } else {
1518                                /* the real master can respond on its own */
1519                                response = DLM_MASTER_RESP_NO;
1520                        }
1521                } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) {
1522                        set_maybe = 0;
1523                        if (tmpmle->master == dlm->node_num) {
1524                                response = DLM_MASTER_RESP_YES;
1525                                /* this node will be the owner.
1526                                 * go back and clean the mles on any
1527                                 * other nodes */
1528                                dispatch_assert = 1;
1529                                dlm_lockres_set_refmap_bit(dlm, res,
1530                                                           request->node_idx);
1531                        } else
1532                                response = DLM_MASTER_RESP_NO;
1533                } else {
1534                        // mlog(0, "this node is attempting to "
1535                        // "master lockres\n");
1536                        response = DLM_MASTER_RESP_MAYBE;
1537                }
1538                if (set_maybe)
1539                        set_bit(request->node_idx, tmpmle->maybe_map);
1540                spin_unlock(&tmpmle->spinlock);
1541
1542                spin_unlock(&dlm->master_lock);
1543                spin_unlock(&res->spinlock);
1544
1545                /* keep the mle attached to heartbeat events */
1546                dlm_put_mle(tmpmle);
1547                if (mle)
1548                        kmem_cache_free(dlm_mle_cache, mle);
1549                goto send_response;
1550        }
1551
1552        /*
1553         * lockres doesn't exist on this node
1554         * if there is an MLE_BLOCK, return NO
1555         * if there is an MLE_MASTER, return MAYBE
1556         * otherwise, add an MLE_BLOCK, return NO
1557         */
1558        spin_lock(&dlm->master_lock);
1559        found = dlm_find_mle(dlm, &tmpmle, name, namelen);
1560        if (!found) {
1561                /* this lockid has never been seen on this node yet */
1562                // mlog(0, "no mle found\n");
1563                if (!mle) {
1564                        spin_unlock(&dlm->master_lock);
1565                        spin_unlock(&dlm->spinlock);
1566
1567                        mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
1568                        if (!mle) {
1569                                response = DLM_MASTER_RESP_ERROR;
1570                                mlog_errno(-ENOMEM);
1571                                goto send_response;
1572                        }
1573                        goto way_up_top;
1574                }
1575
1576                // mlog(0, "this is second time thru, already allocated, "
1577                // "add the block.\n");
1578                dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen);
1579                set_bit(request->node_idx, mle->maybe_map);
1580                __dlm_insert_mle(dlm, mle);
1581                response = DLM_MASTER_RESP_NO;
1582        } else {
1583                spin_lock(&tmpmle->spinlock);
1584                if (tmpmle->master == dlm->node_num) {
1585                        mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n");
1586                        BUG();
1587                }
1588                if (tmpmle->type == DLM_MLE_BLOCK)
1589                        response = DLM_MASTER_RESP_NO;
1590                else if (tmpmle->type == DLM_MLE_MIGRATION) {
1591                        mlog(0, "migration mle was found (%u->%u)\n",
1592                             tmpmle->master, tmpmle->new_master);
1593                        /* real master can respond on its own */
1594                        response = DLM_MASTER_RESP_NO;
1595                } else
1596                        response = DLM_MASTER_RESP_MAYBE;
1597                set_bit(request->node_idx, tmpmle->maybe_map);
1598                spin_unlock(&tmpmle->spinlock);
1599        }
1600        spin_unlock(&dlm->master_lock);
1601        spin_unlock(&dlm->spinlock);
1602
1603        if (found) {
1604                /* keep the mle attached to heartbeat events */
1605                dlm_put_mle(tmpmle);
1606        }
1607send_response:
1608        /*
1609         * __dlm_lookup_lockres() grabbed a reference to this lockres.
1610         * The reference is released by dlm_assert_master_worker() under
1611         * the call to dlm_dispatch_assert_master().  If
1612         * dlm_assert_master_worker() isn't called, we drop it here.
1613         */
1614        if (dispatch_assert) {
1615                mlog(0, "%u is the owner of %.*s, cleaning everyone else\n",
1616                             dlm->node_num, res->lockname.len, res->lockname.name);
1617                spin_lock(&res->spinlock);
1618                ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx,
1619                                                 DLM_ASSERT_MASTER_MLE_CLEANUP);
1620                if (ret < 0) {
1621                        mlog(ML_ERROR, "failed to dispatch assert master work\n");
1622                        response = DLM_MASTER_RESP_ERROR;
1623                        spin_unlock(&res->spinlock);
1624                        dlm_lockres_put(res);
1625                } else {
1626                        dispatched = 1;
1627                        __dlm_lockres_grab_inflight_worker(dlm, res);
1628                        spin_unlock(&res->spinlock);
1629                }
1630        } else {
1631                if (res)
1632                        dlm_lockres_put(res);
1633        }
1634
1635        if (!dispatched)
1636                dlm_put(dlm);
1637        return response;
1638}
1639
1640/*
1641 * DLM_ASSERT_MASTER_MSG
1642 */
1643
1644
1645/*
1646 * NOTE: this can be used for debugging
1647 * can periodically run all locks owned by this node
1648 * and re-assert across the cluster...
1649 */
1650static int dlm_do_assert_master(struct dlm_ctxt *dlm,
1651                                struct dlm_lock_resource *res,
1652                                void *nodemap, u32 flags)
1653{
1654        struct dlm_assert_master assert;
1655        int to, tmpret;
1656        struct dlm_node_iter iter;
1657        int ret = 0;
1658        int reassert;
1659        const char *lockname = res->lockname.name;
1660        unsigned int namelen = res->lockname.len;
1661
1662        BUG_ON(namelen > O2NM_MAX_NAME_LEN);
1663
1664        spin_lock(&res->spinlock);
1665        res->state |= DLM_LOCK_RES_SETREF_INPROG;
1666        spin_unlock(&res->spinlock);
1667
1668again:
1669        reassert = 0;
1670
1671        /* note that if this nodemap is empty, it returns 0 */
1672        dlm_node_iter_init(nodemap, &iter);
1673        while ((to = dlm_node_iter_next(&iter)) >= 0) {
1674                int r = 0;
1675                struct dlm_master_list_entry *mle = NULL;
1676
1677                mlog(0, "sending assert master to %d (%.*s)\n", to,
1678                     namelen, lockname);
1679                memset(&assert, 0, sizeof(assert));
1680                assert.node_idx = dlm->node_num;
1681                assert.namelen = namelen;
1682                memcpy(assert.name, lockname, namelen);
1683                assert.flags = cpu_to_be32(flags);
1684
1685                tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key,
1686                                            &assert, sizeof(assert), to, &r);
1687                if (tmpret < 0) {
1688                        mlog(ML_ERROR, "Error %d when sending message %u (key "
1689                             "0x%x) to node %u\n", tmpret,
1690                             DLM_ASSERT_MASTER_MSG, dlm->key, to);
1691                        if (!dlm_is_host_down(tmpret)) {
1692                                mlog(ML_ERROR, "unhandled error=%d!\n", tmpret);
1693                                BUG();
1694                        }
1695                        /* a node died.  finish out the rest of the nodes. */
1696                        mlog(0, "link to %d went down!\n", to);
1697                        /* any nonzero status return will do */
1698                        ret = tmpret;
1699                        r = 0;
1700                } else if (r < 0) {
1701                        /* ok, something horribly messed.  kill thyself. */
1702                        mlog(ML_ERROR,"during assert master of %.*s to %u, "
1703                             "got %d.\n", namelen, lockname, to, r);
1704                        spin_lock(&dlm->spinlock);
1705                        spin_lock(&dlm->master_lock);
1706                        if (dlm_find_mle(dlm, &mle, (char *)lockname,
1707                                         namelen)) {
1708                                dlm_print_one_mle(mle);
1709                                __dlm_put_mle(mle);
1710                        }
1711                        spin_unlock(&dlm->master_lock);
1712                        spin_unlock(&dlm->spinlock);
1713                        BUG();
1714                }
1715
1716                if (r & DLM_ASSERT_RESPONSE_REASSERT &&
1717                    !(r & DLM_ASSERT_RESPONSE_MASTERY_REF)) {
1718                                mlog(ML_ERROR, "%.*s: very strange, "
1719                                     "master MLE but no lockres on %u\n",
1720                                     namelen, lockname, to);
1721                }
1722
1723                if (r & DLM_ASSERT_RESPONSE_REASSERT) {
1724                        mlog(0, "%.*s: node %u create mles on other "
1725                             "nodes and requests a re-assert\n",
1726                             namelen, lockname, to);
1727                        reassert = 1;
1728                }
1729                if (r & DLM_ASSERT_RESPONSE_MASTERY_REF) {
1730                        mlog(0, "%.*s: node %u has a reference to this "
1731                             "lockres, set the bit in the refmap\n",
1732                             namelen, lockname, to);
1733                        spin_lock(&res->spinlock);
1734                        dlm_lockres_set_refmap_bit(dlm, res, to);
1735                        spin_unlock(&res->spinlock);
1736                }
1737        }
1738
1739        if (reassert)
1740                goto again;
1741
1742        spin_lock(&res->spinlock);
1743        res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
1744        spin_unlock(&res->spinlock);
1745        wake_up(&res->wq);
1746
1747        return ret;
1748}
1749
1750/*
1751 * locks that can be taken here:
1752 * dlm->spinlock
1753 * res->spinlock
1754 * mle->spinlock
1755 * dlm->master_list
1756 *
1757 * if possible, TRIM THIS DOWN!!!
1758 */
1759int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data,
1760                              void **ret_data)
1761{
1762        struct dlm_ctxt *dlm = data;
1763        struct dlm_master_list_entry *mle = NULL;
1764        struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf;
1765        struct dlm_lock_resource *res = NULL;
1766        char *name;
1767        unsigned int namelen, hash;
1768        u32 flags;
1769        int master_request = 0, have_lockres_ref = 0;
1770        int ret = 0;
1771
1772        if (!dlm_grab(dlm))
1773                return 0;
1774
1775        name = assert->name;
1776        namelen = assert->namelen;
1777        hash = dlm_lockid_hash(name, namelen);
1778        flags = be32_to_cpu(assert->flags);
1779
1780        if (namelen > DLM_LOCKID_NAME_MAX) {
1781                mlog(ML_ERROR, "Invalid name length!");
1782                goto done;
1783        }
1784
1785        spin_lock(&dlm->spinlock);
1786
1787        if (flags)
1788                mlog(0, "assert_master with flags: %u\n", flags);
1789
1790        /* find the MLE */
1791        spin_lock(&dlm->master_lock);
1792        if (!dlm_find_mle(dlm, &mle, name, namelen)) {
1793                /* not an error, could be master just re-asserting */
1794                mlog(0, "just got an assert_master from %u, but no "
1795                     "MLE for it! (%.*s)\n", assert->node_idx,
1796                     namelen, name);
1797        } else {
1798                int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0);
1799                if (bit >= O2NM_MAX_NODES) {
1800                        /* not necessarily an error, though less likely.
1801                         * could be master just re-asserting. */
1802                        mlog(0, "no bits set in the maybe_map, but %u "
1803                             "is asserting! (%.*s)\n", assert->node_idx,
1804                             namelen, name);
1805                } else if (bit != assert->node_idx) {
1806                        if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1807                                mlog(0, "master %u was found, %u should "
1808                                     "back off\n", assert->node_idx, bit);
1809                        } else {
1810                                /* with the fix for bug 569, a higher node
1811                                 * number winning the mastery will respond
1812                                 * YES to mastery requests, but this node
1813                                 * had no way of knowing.  let it pass. */
1814                                mlog(0, "%u is the lowest node, "
1815                                     "%u is asserting. (%.*s)  %u must "
1816                                     "have begun after %u won.\n", bit,
1817                                     assert->node_idx, namelen, name, bit,
1818                                     assert->node_idx);
1819                        }
1820                }
1821                if (mle->type == DLM_MLE_MIGRATION) {
1822                        if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) {
1823                                mlog(0, "%s:%.*s: got cleanup assert"
1824                                     " from %u for migration\n",
1825                                     dlm->name, namelen, name,
1826                                     assert->node_idx);
1827                        } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) {
1828                                mlog(0, "%s:%.*s: got unrelated assert"
1829                                     " from %u for migration, ignoring\n",
1830                                     dlm->name, namelen, name,
1831                                     assert->node_idx);
1832                                __dlm_put_mle(mle);
1833                                spin_unlock(&dlm->master_lock);
1834                                spin_unlock(&dlm->spinlock);
1835                                goto done;
1836                        }
1837                }
1838        }
1839        spin_unlock(&dlm->master_lock);
1840
1841        /* ok everything checks out with the MLE
1842         * now check to see if there is a lockres */
1843        res = __dlm_lookup_lockres(dlm, name, namelen, hash);
1844        if (res) {
1845                spin_lock(&res->spinlock);
1846                if (res->state & DLM_LOCK_RES_RECOVERING)  {
1847                        mlog(ML_ERROR, "%u asserting but %.*s is "
1848                             "RECOVERING!\n", assert->node_idx, namelen, name);
1849                        goto kill;
1850                }
1851                if (!mle) {
1852                        if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN &&
1853                            res->owner != assert->node_idx) {
1854                                mlog(ML_ERROR, "DIE! Mastery assert from %u, "
1855                                     "but current owner is %u! (%.*s)\n",
1856                                     assert->node_idx, res->owner, namelen,
1857                                     name);
1858                                __dlm_print_one_lock_resource(res);
1859                                BUG();
1860                        }
1861                } else if (mle->type != DLM_MLE_MIGRATION) {
1862                        if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) {
1863                                /* owner is just re-asserting */
1864                                if (res->owner == assert->node_idx) {
1865                                        mlog(0, "owner %u re-asserting on "
1866                                             "lock %.*s\n", assert->node_idx,
1867                                             namelen, name);
1868                                        goto ok;
1869                                }
1870                                mlog(ML_ERROR, "got assert_master from "
1871                                     "node %u, but %u is the owner! "
1872                                     "(%.*s)\n", assert->node_idx,
1873                                     res->owner, namelen, name);
1874                                goto kill;
1875                        }
1876                        if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) {
1877                                mlog(ML_ERROR, "got assert from %u, but lock "
1878                                     "with no owner should be "
1879                                     "in-progress! (%.*s)\n",
1880                                     assert->node_idx,
1881                                     namelen, name);
1882                                goto kill;
1883                        }
1884                } else /* mle->type == DLM_MLE_MIGRATION */ {
1885                        /* should only be getting an assert from new master */
1886                        if (assert->node_idx != mle->new_master) {
1887                                mlog(ML_ERROR, "got assert from %u, but "
1888                                     "new master is %u, and old master "
1889                                     "was %u (%.*s)\n",
1890                                     assert->node_idx, mle->new_master,
1891                                     mle->master, namelen, name);
1892                                goto kill;
1893                        }
1894
1895                }
1896ok:
1897                spin_unlock(&res->spinlock);
1898        }
1899
1900        // mlog(0, "woo!  got an assert_master from node %u!\n",
1901        //           assert->node_idx);
1902        if (mle) {
1903                int extra_ref = 0;
1904                int nn = -1;
1905                int rr, err = 0;
1906
1907                spin_lock(&mle->spinlock);
1908                if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION)
1909                        extra_ref = 1;
1910                else {
1911                        /* MASTER mle: if any bits set in the response map
1912                         * then the calling node needs to re-assert to clear
1913                         * up nodes that this node contacted */
1914                        while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES,
1915                                                    nn+1)) < O2NM_MAX_NODES) {
1916                                if (nn != dlm->node_num && nn != assert->node_idx) {
1917                                        master_request = 1;
1918                                        break;
1919                                }
1920                        }
1921                }
1922                mle->master = assert->node_idx;
1923                atomic_set(&mle->woken, 1);
1924                wake_up(&mle->wq);
1925                spin_unlock(&mle->spinlock);
1926
1927                if (res) {
1928                        int wake = 0;
1929                        spin_lock(&res->spinlock);
1930                        if (mle->type == DLM_MLE_MIGRATION) {
1931                                mlog(0, "finishing off migration of lockres %.*s, "
1932                                        "from %u to %u\n",
1933                                        res->lockname.len, res->lockname.name,
1934                                        dlm->node_num, mle->new_master);
1935                                res->state &= ~DLM_LOCK_RES_MIGRATING;
1936                                wake = 1;
1937                                dlm_change_lockres_owner(dlm, res, mle->new_master);
1938                                BUG_ON(res->state & DLM_LOCK_RES_DIRTY);
1939                        } else {
1940                                dlm_change_lockres_owner(dlm, res, mle->master);
1941                        }
1942                        spin_unlock(&res->spinlock);
1943                        have_lockres_ref = 1;
1944                        if (wake)
1945                                wake_up(&res->wq);
1946                }
1947
1948                /* master is known, detach if not already detached.
1949                 * ensures that only one assert_master call will happen
1950                 * on this mle. */
1951                spin_lock(&dlm->master_lock);
1952
1953                rr = kref_read(&mle->mle_refs);
1954                if (mle->inuse > 0) {
1955                        if (extra_ref && rr < 3)
1956                                err = 1;
1957                        else if (!extra_ref && rr < 2)
1958                                err = 1;
1959                } else {
1960                        if (extra_ref && rr < 2)
1961                                err = 1;
1962                        else if (!extra_ref && rr < 1)
1963                                err = 1;
1964                }
1965                if (err) {
1966                        mlog(ML_ERROR, "%s:%.*s: got assert master from %u "
1967                             "that will mess up this node, refs=%d, extra=%d, "
1968                             "inuse=%d\n", dlm->name, namelen, name,
1969                             assert->node_idx, rr, extra_ref, mle->inuse);
1970                        dlm_print_one_mle(mle);
1971                }
1972                __dlm_unlink_mle(dlm, mle);
1973                __dlm_mle_detach_hb_events(dlm, mle);
1974                __dlm_put_mle(mle);
1975                if (extra_ref) {
1976                        /* the assert master message now balances the extra
1977                         * ref given by the master / migration request message.
1978                         * if this is the last put, it will be removed
1979                         * from the list. */
1980                        __dlm_put_mle(mle);
1981                }
1982                spin_unlock(&dlm->master_lock);
1983        } else if (res) {
1984                if (res->owner != assert->node_idx) {
1985                        mlog(0, "assert_master from %u, but current "
1986                             "owner is %u (%.*s), no mle\n", assert->node_idx,
1987                             res->owner, namelen, name);
1988                }
1989        }
1990        spin_unlock(&dlm->spinlock);
1991
1992done:
1993        ret = 0;
1994        if (res) {
1995                spin_lock(&res->spinlock);
1996                res->state |= DLM_LOCK_RES_SETREF_INPROG;
1997                spin_unlock(&res->spinlock);
1998                *ret_data = (void *)res;
1999        }
2000        dlm_put(dlm);
2001        if (master_request) {
2002                mlog(0, "need to tell master to reassert\n");
2003                /* positive. negative would shoot down the node. */
2004                ret |= DLM_ASSERT_RESPONSE_REASSERT;
2005                if (!have_lockres_ref) {
2006                        mlog(ML_ERROR, "strange, got assert from %u, MASTER "
2007                             "mle present here for %s:%.*s, but no lockres!\n",
2008                             assert->node_idx, dlm->name, namelen, name);
2009                }
2010        }
2011        if (have_lockres_ref) {
2012                /* let the master know we have a reference to the lockres */
2013                ret |= DLM_ASSERT_RESPONSE_MASTERY_REF;
2014                mlog(0, "%s:%.*s: got assert from %u, need a ref\n",
2015                     dlm->name, namelen, name, assert->node_idx);
2016        }
2017        return ret;
2018
2019kill:
2020        /* kill the caller! */
2021        mlog(ML_ERROR, "Bad message received from another node.  Dumping state "
2022             "and killing the other node now!  This node is OK and can continue.\n");
2023        __dlm_print_one_lock_resource(res);
2024        spin_unlock(&res->spinlock);
2025        spin_lock(&dlm->master_lock);
2026        if (mle)
2027                __dlm_put_mle(mle);
2028        spin_unlock(&dlm->master_lock);
2029        spin_unlock(&dlm->spinlock);
2030        *ret_data = (void *)res;
2031        dlm_put(dlm);
2032        return -EINVAL;
2033}
2034
2035void dlm_assert_master_post_handler(int status, void *data, void *ret_data)
2036{
2037        struct dlm_lock_resource *res = (struct dlm_lock_resource *)ret_data;
2038
2039        if (ret_data) {
2040                spin_lock(&res->spinlock);
2041                res->state &= ~DLM_LOCK_RES_SETREF_INPROG;
2042                spin_unlock(&res->spinlock);
2043                wake_up(&res->wq);
2044                dlm_lockres_put(res);
2045        }
2046        return;
2047}
2048
2049int dlm_dispatch_assert_master(struct dlm_ctxt *dlm,
2050                               struct dlm_lock_resource *res,
2051                               int ignore_higher, u8 request_from, u32 flags)
2052{
2053        struct dlm_work_item *item;
2054        item = kzalloc(sizeof(*item), GFP_ATOMIC);
2055        if (!item)
2056                return -ENOMEM;
2057
2058
2059        /* queue up work for dlm_assert_master_worker */
2060        dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL);
2061        item->u.am.lockres = res; /* already have a ref */
2062        /* can optionally ignore node numbers higher than this node */
2063        item->u.am.ignore_higher = ignore_higher;
2064        item->u.am.request_from = request_from;
2065        item->u.am.flags = flags;
2066
2067        if (ignore_higher)
2068                mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len,
2069                     res->lockname.name);
2070
2071        spin_lock(&dlm->work_lock);
2072        list_add_tail(&item->list, &dlm->work_list);
2073        spin_unlock(&dlm->work_lock);
2074
2075        queue_work(dlm->dlm_worker, &dlm->dispatched_work);
2076        return 0;
2077}
2078
2079static void dlm_assert_master_worker(struct dlm_work_item *item, void *data)
2080{
2081        struct dlm_ctxt *dlm = data;
2082        int ret = 0;
2083        struct dlm_lock_resource *res;
2084        unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)];
2085        int ignore_higher;
2086        int bit;
2087        u8 request_from;
2088        u32 flags;
2089
2090        dlm = item->dlm;
2091        res = item->u.am.lockres;
2092        ignore_higher = item->u.am.ignore_higher;
2093        request_from = item->u.am.request_from;
2094        flags = item->u.am.flags;
2095
2096        spin_lock(&dlm->spinlock);
2097        memcpy(nodemap, dlm->domain_map, sizeof(nodemap));
2098        spin_unlock(&dlm->spinlock);
2099
2100        clear_bit(dlm->node_num, nodemap);
2101        if (ignore_higher) {
2102                /* if is this just to clear up mles for nodes below
2103                 * this node, do not send the message to the original
2104                 * caller or any node number higher than this */
2105                clear_bit(request_from, nodemap);
2106                bit = dlm->node_num;
2107                while (1) {
2108                        bit = find_next_bit(nodemap, O2NM_MAX_NODES,
2109                                            bit+1);
2110                        if (bit >= O2NM_MAX_NODES)
2111                                break;
2112                        clear_bit(bit, nodemap);
2113                }
2114        }
2115
2116        /*
2117         * If we're migrating this lock to someone else, we are no
2118         * longer allowed to assert out own mastery.  OTOH, we need to
2119         * prevent migration from starting while we're still asserting
2120         * our dominance.  The reserved ast delays migration.
2121         */
2122        spin_lock(&res->spinlock);
2123        if (res->state & DLM_LOCK_RES_MIGRATING) {
2124                mlog(0, "Someone asked us to assert mastery, but we're "
2125                     "in the middle of migration.  Skipping assert, "
2126                     "the new master will handle that.\n");
2127                spin_unlock(&res->spinlock);
2128                goto put;
2129        } else
2130                __dlm_lockres_reserve_ast(res);
2131        spin_unlock(&res->spinlock);
2132
2133        /* this call now finishes out the nodemap
2134         * even if one or more nodes die */
2135        mlog(0, "worker about to master %.*s here, this=%u\n",
2136                     res->lockname.len, res->lockname.name, dlm->node_num);
2137        ret = dlm_do_assert_master(dlm, res, nodemap, flags);
2138        if (ret < 0) {
2139                /* no need to restart, we are done */
2140                if (!dlm_is_host_down(ret))
2141                        mlog_errno(ret);
2142        }
2143
2144        /* Ok, we've asserted ourselves.  Let's let migration start. */
2145        dlm_lockres_release_ast(dlm, res);
2146
2147put:
2148        dlm_lockres_drop_inflight_worker(dlm, res);
2149
2150        dlm_lockres_put(res);
2151
2152        mlog(0, "finished with dlm_assert_master_worker\n");
2153}
2154
2155/* SPECIAL CASE for the $RECOVERY lock used by the recovery thread.
2156 * We cannot wait for node recovery to complete to begin mastering this
2157 * lockres because this lockres is used to kick off recovery! ;-)
2158 * So, do a pre-check on all living nodes to see if any of those nodes
2159 * think that $RECOVERY is currently mastered by a dead node.  If so,
2160 * we wait a short time to allow that node to get notified by its own
2161 * heartbeat stack, then check again.  All $RECOVERY lock resources
2162 * mastered by dead nodes are purged when the heartbeat callback is
2163 * fired, so we can know for sure that it is safe to continue once
2164 * the node returns a live node or no node.  */
2165static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm,
2166                                       struct dlm_lock_resource *res)
2167{
2168        struct dlm_node_iter iter;
2169        int nodenum;
2170        int ret = 0;
2171        u8 master = DLM_LOCK_RES_OWNER_UNKNOWN;
2172
2173        spin_lock(&dlm->spinlock);
2174        dlm_node_iter_init(dlm->domain_map, &iter);
2175        spin_unlock(&dlm->spinlock);
2176
2177        while ((nodenum = dlm_node_iter_next(&iter)) >= 0) {
2178                /* do not send to self */
2179                if (nodenum == dlm->node_num)
2180                        continue;
2181                ret = dlm_do_master_requery(dlm, res, nodenum, &master);
2182                if (ret < 0) {
2183                        mlog_errno(ret);
2184                        if (!dlm_is_host_down(ret))
2185                                BUG();
2186                        /* host is down, so answer for that node would be
2187                         * DLM_LOCK_RES_OWNER_UNKNOWN.  continue. */
2188                        ret = 0;
2189                }
2190
2191                if (master != DLM_LOCK_RES_OWNER_UNKNOWN) {
2192                        /* check to see if this master is in the recovery map */
2193                        spin_lock(&dlm->spinlock);
2194                        if (test_bit(master, dlm->recovery_map)) {
2195                                mlog(ML_NOTICE, "%s: node %u has not seen "
2196                                     "node %u go down yet, and thinks the "
2197                                     "dead node is mastering the recovery "
2198                                     "lock.  must wait.\n", dlm->name,
2199                                     nodenum, master);
2200                                ret = -EAGAIN;
2201                        }
2202                        spin_unlock(&dlm->spinlock);
2203                        mlog(0, "%s: reco lock master is %u\n", dlm->name,
2204                             master);
2205                        break;
2206                }
2207        }
2208        return ret;
2209}
2210
2211/*
2212 * DLM_DEREF_LOCKRES_MSG
2213 */
2214
2215int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2216{
2217        struct dlm_deref_lockres deref;
2218        int ret = 0, r;
2219        const char *lockname;
2220        unsigned int namelen;
2221
2222        lockname = res->lockname.name;
2223        namelen = res->lockname.len;
2224        BUG_ON(namelen > O2NM_MAX_NAME_LEN);
2225
2226        memset(&deref, 0, sizeof(deref));
2227        deref.node_idx = dlm->node_num;
2228        deref.namelen = namelen;
2229        memcpy(deref.name, lockname, namelen);
2230
2231        ret = o2net_send_message(DLM_DEREF_LOCKRES_MSG, dlm->key,
2232                                 &deref, sizeof(deref), res->owner, &r);
2233        if (ret < 0)
2234                mlog(ML_ERROR, "%s: res %.*s, error %d send DEREF to node %u\n",
2235                     dlm->name, namelen, lockname, ret, res->owner);
2236        else if (r < 0) {
2237                /* BAD.  other node says I did not have a ref. */
2238                mlog(ML_ERROR, "%s: res %.*s, DEREF to node %u got %d\n",
2239                     dlm->name, namelen, lockname, res->owner, r);
2240                dlm_print_one_lock_resource(res);
2241                if (r == -ENOMEM)
2242                        BUG();
2243        } else
2244                ret = r;
2245
2246        return ret;
2247}
2248
2249int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data,
2250                              void **ret_data)
2251{
2252        struct dlm_ctxt *dlm = data;
2253        struct dlm_deref_lockres *deref = (struct dlm_deref_lockres *)msg->buf;
2254        struct dlm_lock_resource *res = NULL;
2255        char *name;
2256        unsigned int namelen;
2257        int ret = -EINVAL;
2258        u8 node;
2259        unsigned int hash;
2260        struct dlm_work_item *item;
2261        int cleared = 0;
2262        int dispatch = 0;
2263
2264        if (!dlm_grab(dlm))
2265                return 0;
2266
2267        name = deref->name;
2268        namelen = deref->namelen;
2269        node = deref->node_idx;
2270
2271        if (namelen > DLM_LOCKID_NAME_MAX) {
2272                mlog(ML_ERROR, "Invalid name length!");
2273                goto done;
2274        }
2275        if (deref->node_idx >= O2NM_MAX_NODES) {
2276                mlog(ML_ERROR, "Invalid node number: %u\n", node);
2277                goto done;
2278        }
2279
2280        hash = dlm_lockid_hash(name, namelen);
2281
2282        spin_lock(&dlm->spinlock);
2283        res = __dlm_lookup_lockres_full(dlm, name, namelen, hash);
2284        if (!res) {
2285                spin_unlock(&dlm->spinlock);
2286                mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
2287                     dlm->name, namelen, name);
2288                goto done;
2289        }
2290        spin_unlock(&dlm->spinlock);
2291
2292        spin_lock(&res->spinlock);
2293        if (res->state & DLM_LOCK_RES_SETREF_INPROG)
2294                dispatch = 1;
2295        else {
2296                BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2297                if (test_bit(node, res->refmap)) {
2298                        dlm_lockres_clear_refmap_bit(dlm, res, node);
2299                        cleared = 1;
2300                }
2301        }
2302        spin_unlock(&res->spinlock);
2303
2304        if (!dispatch) {
2305                if (cleared)
2306                        dlm_lockres_calc_usage(dlm, res);
2307                else {
2308                        mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2309                        "but it is already dropped!\n", dlm->name,
2310                        res->lockname.len, res->lockname.name, node);
2311                        dlm_print_one_lock_resource(res);
2312                }
2313                ret = DLM_DEREF_RESPONSE_DONE;
2314                goto done;
2315        }
2316
2317        item = kzalloc(sizeof(*item), GFP_NOFS);
2318        if (!item) {
2319                ret = -ENOMEM;
2320                mlog_errno(ret);
2321                goto done;
2322        }
2323
2324        dlm_init_work_item(dlm, item, dlm_deref_lockres_worker, NULL);
2325        item->u.dl.deref_res = res;
2326        item->u.dl.deref_node = node;
2327
2328        spin_lock(&dlm->work_lock);
2329        list_add_tail(&item->list, &dlm->work_list);
2330        spin_unlock(&dlm->work_lock);
2331
2332        queue_work(dlm->dlm_worker, &dlm->dispatched_work);
2333        return DLM_DEREF_RESPONSE_INPROG;
2334
2335done:
2336        if (res)
2337                dlm_lockres_put(res);
2338        dlm_put(dlm);
2339
2340        return ret;
2341}
2342
2343int dlm_deref_lockres_done_handler(struct o2net_msg *msg, u32 len, void *data,
2344                              void **ret_data)
2345{
2346        struct dlm_ctxt *dlm = data;
2347        struct dlm_deref_lockres_done *deref
2348                        = (struct dlm_deref_lockres_done *)msg->buf;
2349        struct dlm_lock_resource *res = NULL;
2350        char *name;
2351        unsigned int namelen;
2352        int ret = -EINVAL;
2353        u8 node;
2354        unsigned int hash;
2355
2356        if (!dlm_grab(dlm))
2357                return 0;
2358
2359        name = deref->name;
2360        namelen = deref->namelen;
2361        node = deref->node_idx;
2362
2363        if (namelen > DLM_LOCKID_NAME_MAX) {
2364                mlog(ML_ERROR, "Invalid name length!");
2365                goto done;
2366        }
2367        if (deref->node_idx >= O2NM_MAX_NODES) {
2368                mlog(ML_ERROR, "Invalid node number: %u\n", node);
2369                goto done;
2370        }
2371
2372        hash = dlm_lockid_hash(name, namelen);
2373
2374        spin_lock(&dlm->spinlock);
2375        res = __dlm_lookup_lockres_full(dlm, name, namelen, hash);
2376        if (!res) {
2377                spin_unlock(&dlm->spinlock);
2378                mlog(ML_ERROR, "%s:%.*s: bad lockres name\n",
2379                     dlm->name, namelen, name);
2380                goto done;
2381        }
2382
2383        spin_lock(&res->spinlock);
2384        if (!(res->state & DLM_LOCK_RES_DROPPING_REF)) {
2385                spin_unlock(&res->spinlock);
2386                spin_unlock(&dlm->spinlock);
2387                mlog(ML_NOTICE, "%s:%.*s: node %u sends deref done "
2388                        "but it is already derefed!\n", dlm->name,
2389                        res->lockname.len, res->lockname.name, node);
2390                ret = 0;
2391                goto done;
2392        }
2393
2394        __dlm_do_purge_lockres(dlm, res);
2395        spin_unlock(&res->spinlock);
2396        wake_up(&res->wq);
2397
2398        spin_unlock(&dlm->spinlock);
2399
2400        ret = 0;
2401done:
2402        if (res)
2403                dlm_lockres_put(res);
2404        dlm_put(dlm);
2405        return ret;
2406}
2407
2408static void dlm_drop_lockres_ref_done(struct dlm_ctxt *dlm,
2409                struct dlm_lock_resource *res, u8 node)
2410{
2411        struct dlm_deref_lockres_done deref;
2412        int ret = 0, r;
2413        const char *lockname;
2414        unsigned int namelen;
2415
2416        lockname = res->lockname.name;
2417        namelen = res->lockname.len;
2418        BUG_ON(namelen > O2NM_MAX_NAME_LEN);
2419
2420        memset(&deref, 0, sizeof(deref));
2421        deref.node_idx = dlm->node_num;
2422        deref.namelen = namelen;
2423        memcpy(deref.name, lockname, namelen);
2424
2425        ret = o2net_send_message(DLM_DEREF_LOCKRES_DONE, dlm->key,
2426                                 &deref, sizeof(deref), node, &r);
2427        if (ret < 0) {
2428                mlog(ML_ERROR, "%s: res %.*s, error %d send DEREF DONE "
2429                                " to node %u\n", dlm->name, namelen,
2430                                lockname, ret, node);
2431        } else if (r < 0) {
2432                /* ignore the error */
2433                mlog(ML_ERROR, "%s: res %.*s, DEREF to node %u got %d\n",
2434                     dlm->name, namelen, lockname, node, r);
2435                dlm_print_one_lock_resource(res);
2436        }
2437}
2438
2439static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data)
2440{
2441        struct dlm_ctxt *dlm;
2442        struct dlm_lock_resource *res;
2443        u8 node;
2444        u8 cleared = 0;
2445
2446        dlm = item->dlm;
2447        res = item->u.dl.deref_res;
2448        node = item->u.dl.deref_node;
2449
2450        spin_lock(&res->spinlock);
2451        BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF);
2452        __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG);
2453        if (test_bit(node, res->refmap)) {
2454                dlm_lockres_clear_refmap_bit(dlm, res, node);
2455                cleared = 1;
2456        }
2457        spin_unlock(&res->spinlock);
2458
2459        dlm_drop_lockres_ref_done(dlm, res, node);
2460
2461        if (cleared) {
2462                mlog(0, "%s:%.*s node %u ref dropped in dispatch\n",
2463                     dlm->name, res->lockname.len, res->lockname.name, node);
2464                dlm_lockres_calc_usage(dlm, res);
2465        } else {
2466                mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref "
2467                     "but it is already dropped!\n", dlm->name,
2468                     res->lockname.len, res->lockname.name, node);
2469                dlm_print_one_lock_resource(res);
2470        }
2471
2472        dlm_lockres_put(res);
2473}
2474
2475/*
2476 * A migratable resource is one that is :
2477 * 1. locally mastered, and,
2478 * 2. zero local locks, and,
2479 * 3. one or more non-local locks, or, one or more references
2480 * Returns 1 if yes, 0 if not.
2481 */
2482static int dlm_is_lockres_migratable(struct dlm_ctxt *dlm,
2483                                      struct dlm_lock_resource *res)
2484{
2485        enum dlm_lockres_list idx;
2486        int nonlocal = 0, node_ref;
2487        struct list_head *queue;
2488        struct dlm_lock *lock;
2489        u64 cookie;
2490
2491        assert_spin_locked(&res->spinlock);
2492
2493        /* delay migration when the lockres is in MIGRATING state */
2494        if (res->state & DLM_LOCK_RES_MIGRATING)
2495                return 0;
2496
2497        /* delay migration when the lockres is in RECOCERING state */
2498        if (res->state & (DLM_LOCK_RES_RECOVERING|
2499                        DLM_LOCK_RES_RECOVERY_WAITING))
2500                return 0;
2501
2502        if (res->owner != dlm->node_num)
2503                return 0;
2504
2505        for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
2506                queue = dlm_list_idx_to_ptr(res, idx);
2507                list_for_each_entry(lock, queue, list) {
2508                        if (lock->ml.node != dlm->node_num) {
2509                                nonlocal++;
2510                                continue;
2511                        }
2512                        cookie = be64_to_cpu(lock->ml.cookie);
2513                        mlog(0, "%s: Not migratable res %.*s, lock %u:%llu on "
2514                             "%s list\n", dlm->name, res->lockname.len,
2515                             res->lockname.name,
2516                             dlm_get_lock_cookie_node(cookie),
2517                             dlm_get_lock_cookie_seq(cookie),
2518                             dlm_list_in_text(idx));
2519                        return 0;
2520                }
2521        }
2522
2523        if (!nonlocal) {
2524                node_ref = find_next_bit(res->refmap, O2NM_MAX_NODES, 0);
2525                if (node_ref >= O2NM_MAX_NODES)
2526                        return 0;
2527        }
2528
2529        mlog(0, "%s: res %.*s, Migratable\n", dlm->name, res->lockname.len,
2530             res->lockname.name);
2531
2532        return 1;
2533}
2534
2535/*
2536 * DLM_MIGRATE_LOCKRES
2537 */
2538
2539
2540static int dlm_migrate_lockres(struct dlm_ctxt *dlm,
2541                               struct dlm_lock_resource *res, u8 target)
2542{
2543        struct dlm_master_list_entry *mle = NULL;
2544        struct dlm_master_list_entry *oldmle = NULL;
2545        struct dlm_migratable_lockres *mres = NULL;
2546        int ret = 0;
2547        const char *name;
2548        unsigned int namelen;
2549        int mle_added = 0;
2550        int wake = 0;
2551
2552        if (!dlm_grab(dlm))
2553                return -EINVAL;
2554
2555        name = res->lockname.name;
2556        namelen = res->lockname.len;
2557
2558        mlog(0, "%s: Migrating %.*s to node %u\n", dlm->name, namelen, name,
2559             target);
2560
2561        /* preallocate up front. if this fails, abort */
2562        ret = -ENOMEM;
2563        mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS);
2564        if (!mres) {
2565                mlog_errno(ret);
2566                goto leave;
2567        }
2568
2569        mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
2570        if (!mle) {
2571                mlog_errno(ret);
2572                goto leave;
2573        }
2574        ret = 0;
2575
2576        /*
2577         * clear any existing master requests and
2578         * add the migration mle to the list
2579         */
2580        spin_lock(&dlm->spinlock);
2581        spin_lock(&dlm->master_lock);
2582        ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name,
2583                                    namelen, target, dlm->node_num);
2584        /* get an extra reference on the mle.
2585         * otherwise the assert_master from the new
2586         * master will destroy this.
2587         */
2588        if (ret != -EEXIST)
2589                dlm_get_mle_inuse(mle);
2590
2591        spin_unlock(&dlm->master_lock);
2592        spin_unlock(&dlm->spinlock);
2593
2594        if (ret == -EEXIST) {
2595                mlog(0, "another process is already migrating it\n");
2596                goto fail;
2597        }
2598        mle_added = 1;
2599
2600        /*
2601         * set the MIGRATING flag and flush asts
2602         * if we fail after this we need to re-dirty the lockres
2603         */
2604        if (dlm_mark_lockres_migrating(dlm, res, target) < 0) {
2605                mlog(ML_ERROR, "tried to migrate %.*s to %u, but "
2606                     "the target went down.\n", res->lockname.len,
2607                     res->lockname.name, target);
2608                spin_lock(&res->spinlock);
2609                res->state &= ~DLM_LOCK_RES_MIGRATING;
2610                wake = 1;
2611                spin_unlock(&res->spinlock);
2612                ret = -EINVAL;
2613        }
2614
2615fail:
2616        if (ret != -EEXIST && oldmle) {
2617                /* master is known, detach if not already detached */
2618                dlm_mle_detach_hb_events(dlm, oldmle);
2619                dlm_put_mle(oldmle);
2620        }
2621
2622        if (ret < 0) {
2623                if (mle_added) {
2624                        dlm_mle_detach_hb_events(dlm, mle);
2625                        dlm_put_mle(mle);
2626                        dlm_put_mle_inuse(mle);
2627                } else if (mle) {
2628                        kmem_cache_free(dlm_mle_cache, mle);
2629                        mle = NULL;
2630                }
2631                goto leave;
2632        }
2633
2634        /*
2635         * at this point, we have a migration target, an mle
2636         * in the master list, and the MIGRATING flag set on
2637         * the lockres
2638         */
2639
2640        /* now that remote nodes are spinning on the MIGRATING flag,
2641         * ensure that all assert_master work is flushed. */
2642        flush_workqueue(dlm->dlm_worker);
2643
2644        /* notify new node and send all lock state */
2645        /* call send_one_lockres with migration flag.
2646         * this serves as notice to the target node that a
2647         * migration is starting. */
2648        ret = dlm_send_one_lockres(dlm, res, mres, target,
2649                                   DLM_MRES_MIGRATION);
2650
2651        if (ret < 0) {
2652                mlog(0, "migration to node %u failed with %d\n",
2653                     target, ret);
2654                /* migration failed, detach and clean up mle */
2655                dlm_mle_detach_hb_events(dlm, mle);
2656                dlm_put_mle(mle);
2657                dlm_put_mle_inuse(mle);
2658                spin_lock(&res->spinlock);
2659                res->state &= ~DLM_LOCK_RES_MIGRATING;
2660                wake = 1;
2661                spin_unlock(&res->spinlock);
2662                if (dlm_is_host_down(ret))
2663                        dlm_wait_for_node_death(dlm, target,
2664                                                DLM_NODE_DEATH_WAIT_MAX);
2665                goto leave;
2666        }
2667
2668        /* at this point, the target sends a message to all nodes,
2669         * (using dlm_do_migrate_request).  this node is skipped since
2670         * we had to put an mle in the list to begin the process.  this
2671         * node now waits for target to do an assert master.  this node
2672         * will be the last one notified, ensuring that the migration
2673         * is complete everywhere.  if the target dies while this is
2674         * going on, some nodes could potentially see the target as the
2675         * master, so it is important that my recovery finds the migration
2676         * mle and sets the master to UNKNOWN. */
2677
2678
2679        /* wait for new node to assert master */
2680        while (1) {
2681                ret = wait_event_interruptible_timeout(mle->wq,
2682                                        (atomic_read(&mle->woken) == 1),
2683                                        msecs_to_jiffies(5000));
2684
2685                if (ret >= 0) {
2686                        if (atomic_read(&mle->woken) == 1 ||
2687                            res->owner == target)
2688                                break;
2689
2690                        mlog(0, "%s:%.*s: timed out during migration\n",
2691                             dlm->name, res->lockname.len, res->lockname.name);
2692                        /* avoid hang during shutdown when migrating lockres
2693                         * to a node which also goes down */
2694                        if (dlm_is_node_dead(dlm, target)) {
2695                                mlog(0, "%s:%.*s: expected migration "
2696                                     "target %u is no longer up, restarting\n",
2697                                     dlm->name, res->lockname.len,
2698                                     res->lockname.name, target);
2699                                ret = -EINVAL;
2700                                /* migration failed, detach and clean up mle */
2701                                dlm_mle_detach_hb_events(dlm, mle);
2702                                dlm_put_mle(mle);
2703                                dlm_put_mle_inuse(mle);
2704                                spin_lock(&res->spinlock);
2705                                res->state &= ~DLM_LOCK_RES_MIGRATING;
2706                                wake = 1;
2707                                spin_unlock(&res->spinlock);
2708                                goto leave;
2709                        }
2710                } else
2711                        mlog(0, "%s:%.*s: caught signal during migration\n",
2712                             dlm->name, res->lockname.len, res->lockname.name);
2713        }
2714
2715        /* all done, set the owner, clear the flag */
2716        spin_lock(&res->spinlock);
2717        dlm_set_lockres_owner(dlm, res, target);
2718        res->state &= ~DLM_LOCK_RES_MIGRATING;
2719        dlm_remove_nonlocal_locks(dlm, res);
2720        spin_unlock(&res->spinlock);
2721        wake_up(&res->wq);
2722
2723        /* master is known, detach if not already detached */
2724        dlm_mle_detach_hb_events(dlm, mle);
2725        dlm_put_mle_inuse(mle);
2726        ret = 0;
2727
2728        dlm_lockres_calc_usage(dlm, res);
2729
2730leave:
2731        /* re-dirty the lockres if we failed */
2732        if (ret < 0)
2733                dlm_kick_thread(dlm, res);
2734
2735        /* wake up waiters if the MIGRATING flag got set
2736         * but migration failed */
2737        if (wake)
2738                wake_up(&res->wq);
2739
2740        if (mres)
2741                free_page((unsigned long)mres);
2742
2743        dlm_put(dlm);
2744
2745        mlog(0, "%s: Migrating %.*s to %u, returns %d\n", dlm->name, namelen,
2746             name, target, ret);
2747        return ret;
2748}
2749
2750/*
2751 * Should be called only after beginning the domain leave process.
2752 * There should not be any remaining locks on nonlocal lock resources,
2753 * and there should be no local locks left on locally mastered resources.
2754 *
2755 * Called with the dlm spinlock held, may drop it to do migration, but
2756 * will re-acquire before exit.
2757 *
2758 * Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped
2759 */
2760int dlm_empty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res)
2761        __must_hold(&dlm->spinlock)
2762{
2763        int ret;
2764        int lock_dropped = 0;
2765        u8 target = O2NM_MAX_NODES;
2766
2767        assert_spin_locked(&dlm->spinlock);
2768
2769        spin_lock(&res->spinlock);
2770        if (dlm_is_lockres_migratable(dlm, res))
2771                target = dlm_pick_migration_target(dlm, res);
2772        spin_unlock(&res->spinlock);
2773
2774        if (target == O2NM_MAX_NODES)
2775                goto leave;
2776
2777        /* Wheee! Migrate lockres here! Will sleep so drop spinlock. */
2778        spin_unlock(&dlm->spinlock);
2779        lock_dropped = 1;
2780        ret = dlm_migrate_lockres(dlm, res, target);
2781        if (ret)
2782                mlog(0, "%s: res %.*s, Migrate to node %u failed with %d\n",
2783                     dlm->name, res->lockname.len, res->lockname.name,
2784                     target, ret);
2785        spin_lock(&dlm->spinlock);
2786leave:
2787        return lock_dropped;
2788}
2789
2790int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock)
2791{
2792        int ret;
2793        spin_lock(&dlm->ast_lock);
2794        spin_lock(&lock->spinlock);
2795        ret = (list_empty(&lock->bast_list) && !lock->bast_pending);
2796        spin_unlock(&lock->spinlock);
2797        spin_unlock(&dlm->ast_lock);
2798        return ret;
2799}
2800
2801static int dlm_migration_can_proceed(struct dlm_ctxt *dlm,
2802                                     struct dlm_lock_resource *res,
2803                                     u8 mig_target)
2804{
2805        int can_proceed;
2806        spin_lock(&res->spinlock);
2807        can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING);
2808        spin_unlock(&res->spinlock);
2809
2810        /* target has died, so make the caller break out of the
2811         * wait_event, but caller must recheck the domain_map */
2812        spin_lock(&dlm->spinlock);
2813        if (!test_bit(mig_target, dlm->domain_map))
2814                can_proceed = 1;
2815        spin_unlock(&dlm->spinlock);
2816        return can_proceed;
2817}
2818
2819static int dlm_lockres_is_dirty(struct dlm_ctxt *dlm,
2820                                struct dlm_lock_resource *res)
2821{
2822        int ret;
2823        spin_lock(&res->spinlock);
2824        ret = !!(res->state & DLM_LOCK_RES_DIRTY);
2825        spin_unlock(&res->spinlock);
2826        return ret;
2827}
2828
2829
2830static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm,
2831                                       struct dlm_lock_resource *res,
2832                                       u8 target)
2833{
2834        int ret = 0;
2835
2836        mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n",
2837               res->lockname.len, res->lockname.name, dlm->node_num,
2838               target);
2839        /* need to set MIGRATING flag on lockres.  this is done by
2840         * ensuring that all asts have been flushed for this lockres. */
2841        spin_lock(&res->spinlock);
2842        BUG_ON(res->migration_pending);
2843        res->migration_pending = 1;
2844        /* strategy is to reserve an extra ast then release
2845         * it below, letting the release do all of the work */
2846        __dlm_lockres_reserve_ast(res);
2847        spin_unlock(&res->spinlock);
2848
2849        /* now flush all the pending asts */
2850        dlm_kick_thread(dlm, res);
2851        /* before waiting on DIRTY, block processes which may
2852         * try to dirty the lockres before MIGRATING is set */
2853        spin_lock(&res->spinlock);
2854        BUG_ON(res->state & DLM_LOCK_RES_BLOCK_DIRTY);
2855        res->state |= DLM_LOCK_RES_BLOCK_DIRTY;
2856        spin_unlock(&res->spinlock);
2857        /* now wait on any pending asts and the DIRTY state */
2858        wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res));
2859        dlm_lockres_release_ast(dlm, res);
2860
2861        mlog(0, "about to wait on migration_wq, dirty=%s\n",
2862               res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no");
2863        /* if the extra ref we just put was the final one, this
2864         * will pass thru immediately.  otherwise, we need to wait
2865         * for the last ast to finish. */
2866again:
2867        ret = wait_event_interruptible_timeout(dlm->migration_wq,
2868                   dlm_migration_can_proceed(dlm, res, target),
2869                   msecs_to_jiffies(1000));
2870        if (ret < 0) {
2871                mlog(0, "woken again: migrating? %s, dead? %s\n",
2872                       res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2873                       test_bit(target, dlm->domain_map) ? "no":"yes");
2874        } else {
2875                mlog(0, "all is well: migrating? %s, dead? %s\n",
2876                       res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no",
2877                       test_bit(target, dlm->domain_map) ? "no":"yes");
2878        }
2879        if (!dlm_migration_can_proceed(dlm, res, target)) {
2880                mlog(0, "trying again...\n");
2881                goto again;
2882        }
2883
2884        ret = 0;
2885        /* did the target go down or die? */
2886        spin_lock(&dlm->spinlock);
2887        if (!test_bit(target, dlm->domain_map)) {
2888                mlog(ML_ERROR, "aha. migration target %u just went down\n",
2889                     target);
2890                ret = -EHOSTDOWN;
2891        }
2892        spin_unlock(&dlm->spinlock);
2893
2894        /*
2895         * if target is down, we need to clear DLM_LOCK_RES_BLOCK_DIRTY for
2896         * another try; otherwise, we are sure the MIGRATING state is there,
2897         * drop the unneeded state which blocked threads trying to DIRTY
2898         */
2899        spin_lock(&res->spinlock);
2900        BUG_ON(!(res->state & DLM_LOCK_RES_BLOCK_DIRTY));
2901        res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY;
2902        if (!ret)
2903                BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING));
2904        else
2905                res->migration_pending = 0;
2906        spin_unlock(&res->spinlock);
2907
2908        /*
2909         * at this point:
2910         *
2911         *   o the DLM_LOCK_RES_MIGRATING flag is set if target not down
2912         *   o there are no pending asts on this lockres
2913         *   o all processes trying to reserve an ast on this
2914         *     lockres must wait for the MIGRATING flag to clear
2915         */
2916        return ret;
2917}
2918
2919/* last step in the migration process.
2920 * original master calls this to free all of the dlm_lock
2921 * structures that used to be for other nodes. */
2922static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm,
2923                                      struct dlm_lock_resource *res)
2924{
2925        struct list_head *queue = &res->granted;
2926        int i, bit;
2927        struct dlm_lock *lock, *next;
2928
2929        assert_spin_locked(&res->spinlock);
2930
2931        BUG_ON(res->owner == dlm->node_num);
2932
2933        for (i=0; i<3; i++) {
2934                list_for_each_entry_safe(lock, next, queue, list) {
2935                        if (lock->ml.node != dlm->node_num) {
2936                                mlog(0, "putting lock for node %u\n",
2937                                     lock->ml.node);
2938                                /* be extra careful */
2939                                BUG_ON(!list_empty(&lock->ast_list));
2940                                BUG_ON(!list_empty(&lock->bast_list));
2941                                BUG_ON(lock->ast_pending);
2942                                BUG_ON(lock->bast_pending);
2943                                dlm_lockres_clear_refmap_bit(dlm, res,
2944                                                             lock->ml.node);
2945                                list_del_init(&lock->list);
2946                                dlm_lock_put(lock);
2947                                /* In a normal unlock, we would have added a
2948                                 * DLM_UNLOCK_FREE_LOCK action. Force it. */
2949                                dlm_lock_put(lock);
2950                        }
2951                }
2952                queue++;
2953        }
2954        bit = 0;
2955        while (1) {
2956                bit = find_next_bit(res->refmap, O2NM_MAX_NODES, bit);
2957                if (bit >= O2NM_MAX_NODES)
2958                        break;
2959                /* do not clear the local node reference, if there is a
2960                 * process holding this, let it drop the ref itself */
2961                if (bit != dlm->node_num) {
2962                        mlog(0, "%s:%.*s: node %u had a ref to this "
2963                             "migrating lockres, clearing\n", dlm->name,
2964                             res->lockname.len, res->lockname.name, bit);
2965                        dlm_lockres_clear_refmap_bit(dlm, res, bit);
2966                }
2967                bit++;
2968        }
2969}
2970
2971/*
2972 * Pick a node to migrate the lock resource to. This function selects a
2973 * potential target based first on the locks and then on refmap. It skips
2974 * nodes that are in the process of exiting the domain.
2975 */
2976static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm,
2977                                    struct dlm_lock_resource *res)
2978{
2979        enum dlm_lockres_list idx;
2980        struct list_head *queue;
2981        struct dlm_lock *lock;
2982        int noderef;
2983        u8 nodenum = O2NM_MAX_NODES;
2984
2985        assert_spin_locked(&dlm->spinlock);
2986        assert_spin_locked(&res->spinlock);
2987
2988        /* Go through all the locks */
2989        for (idx = DLM_GRANTED_LIST; idx <= DLM_BLOCKED_LIST; idx++) {
2990                queue = dlm_list_idx_to_ptr(res, idx);
2991                list_for_each_entry(lock, queue, list) {
2992                        if (lock->ml.node == dlm->node_num)
2993                                continue;
2994                        if (test_bit(lock->ml.node, dlm->exit_domain_map))
2995                                continue;
2996                        nodenum = lock->ml.node;
2997                        goto bail;
2998                }
2999        }
3000
3001        /* Go thru the refmap */
3002        noderef = -1;
3003        while (1) {
3004                noderef = find_next_bit(res->refmap, O2NM_MAX_NODES,
3005                                        noderef + 1);
3006                if (noderef >= O2NM_MAX_NODES)
3007                        break;
3008                if (noderef == dlm->node_num)
3009                        continue;
3010                if (test_bit(noderef, dlm->exit_domain_map))
3011                        continue;
3012                nodenum = noderef;
3013                goto bail;
3014        }
3015
3016bail:
3017        return nodenum;
3018}
3019
3020/* this is called by the new master once all lockres
3021 * data has been received */
3022static int dlm_do_migrate_request(struct dlm_ctxt *dlm,
3023                                  struct dlm_lock_resource *res,
3024                                  u8 master, u8 new_master,
3025                                  struct dlm_node_iter *iter)
3026{
3027        struct dlm_migrate_request migrate;
3028        int ret, skip, status = 0;
3029        int nodenum;
3030
3031        memset(&migrate, 0, sizeof(migrate));
3032        migrate.namelen = res->lockname.len;
3033        memcpy(migrate.name, res->lockname.name, migrate.namelen);
3034        migrate.new_master = new_master;
3035        migrate.master = master;
3036
3037        ret = 0;
3038
3039        /* send message to all nodes, except the master and myself */
3040        while ((nodenum = dlm_node_iter_next(iter)) >= 0) {
3041                if (nodenum == master ||
3042                    nodenum == new_master)
3043                        continue;
3044
3045                /* We could race exit domain. If exited, skip. */
3046                spin_lock(&dlm->spinlock);
3047                skip = (!test_bit(nodenum, dlm->domain_map));
3048                spin_unlock(&dlm->spinlock);
3049                if (skip) {
3050                        clear_bit(nodenum, iter->node_map);
3051                        continue;
3052                }
3053
3054                ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key,
3055                                         &migrate, sizeof(migrate), nodenum,
3056                                         &status);
3057                if (ret < 0) {
3058                        mlog(ML_ERROR, "%s: res %.*s, Error %d send "
3059                             "MIGRATE_REQUEST to node %u\n", dlm->name,
3060                             migrate.namelen, migrate.name, ret, nodenum);
3061                        if (!dlm_is_host_down(ret)) {
3062                                mlog(ML_ERROR, "unhandled error=%d!\n", ret);
3063                                BUG();
3064                        }
3065                        clear_bit(nodenum, iter->node_map);
3066                        ret = 0;
3067                } else if (status < 0) {
3068                        mlog(0, "migrate request (node %u) returned %d!\n",
3069                             nodenum, status);
3070                        ret = status;
3071                } else if (status == DLM_MIGRATE_RESPONSE_MASTERY_REF) {
3072                        /* during the migration request we short-circuited
3073                         * the mastery of the lockres.  make sure we have
3074                         * a mastery ref for nodenum */
3075                        mlog(0, "%s:%.*s: need ref for node %u\n",
3076                             dlm->name, res->lockname.len, res->lockname.name,
3077                             nodenum);
3078                        spin_lock(&res->spinlock);
3079                        dlm_lockres_set_refmap_bit(dlm, res, nodenum);
3080                        spin_unlock(&res->spinlock);
3081                }
3082        }
3083
3084        if (ret < 0)
3085                mlog_errno(ret);
3086
3087        mlog(0, "returning ret=%d\n", ret);
3088        return ret;
3089}
3090
3091
3092/* if there is an existing mle for this lockres, we now know who the master is.
3093 * (the one who sent us *this* message) we can clear it up right away.
3094 * since the process that put the mle on the list still has a reference to it,
3095 * we can unhash it now, set the master and wake the process.  as a result,
3096 * we will have no mle in the list to start with.  now we can add an mle for
3097 * the migration and this should be the only one found for those scanning the
3098 * list.  */
3099int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data,
3100                                void **ret_data)
3101{
3102        struct dlm_ctxt *dlm = data;
3103        struct dlm_lock_resource *res = NULL;
3104        struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf;
3105        struct dlm_master_list_entry *mle = NULL, *oldmle = NULL;
3106        const char *name;
3107        unsigned int namelen, hash;
3108        int ret = 0;
3109
3110        if (!dlm_grab(dlm))
3111                return 0;
3112
3113        name = migrate->name;
3114        namelen = migrate->namelen;
3115        hash = dlm_lockid_hash(name, namelen);
3116
3117        /* preallocate.. if this fails, abort */
3118        mle = kmem_cache_alloc(dlm_mle_cache, GFP_NOFS);
3119
3120        if (!mle) {
3121                ret = -ENOMEM;
3122                goto leave;
3123        }
3124
3125        /* check for pre-existing lock */
3126        spin_lock(&dlm->spinlock);
3127        res = __dlm_lookup_lockres(dlm, name, namelen, hash);
3128        if (res) {
3129                spin_lock(&res->spinlock);
3130                if (res->state & DLM_LOCK_RES_RECOVERING) {
3131                        /* if all is working ok, this can only mean that we got
3132                        * a migrate request from a node that we now see as
3133                        * dead.  what can we do here?  drop it to the floor? */
3134                        spin_unlock(&res->spinlock);
3135                        mlog(ML_ERROR, "Got a migrate request, but the "
3136                             "lockres is marked as recovering!");
3137                        kmem_cache_free(dlm_mle_cache, mle);
3138                        ret = -EINVAL; /* need a better solution */
3139                        goto unlock;
3140                }
3141                res->state |= DLM_LOCK_RES_MIGRATING;
3142                spin_unlock(&res->spinlock);
3143        }
3144
3145        spin_lock(&dlm->master_lock);
3146        /* ignore status.  only nonzero status would BUG. */
3147        ret = dlm_add_migration_mle(dlm, res, mle, &oldmle,
3148                                    name, namelen,
3149                                    migrate->new_master,
3150                                    migrate->master);
3151
3152        if (ret < 0)
3153                kmem_cache_free(dlm_mle_cache, mle);
3154
3155        spin_unlock(&dlm->master_lock);
3156unlock:
3157        spin_unlock(&dlm->spinlock);
3158
3159        if (oldmle) {
3160                /* master is known, detach if not already detached */
3161                dlm_mle_detach_hb_events(dlm, oldmle);
3162                dlm_put_mle(oldmle);
3163        }
3164
3165        if (res)
3166                dlm_lockres_put(res);
3167leave:
3168        dlm_put(dlm);
3169        return ret;
3170}
3171
3172/* must be holding dlm->spinlock and dlm->master_lock
3173 * when adding a migration mle, we can clear any other mles
3174 * in the master list because we know with certainty that
3175 * the master is "master".  so we remove any old mle from
3176 * the list after setting it's master field, and then add
3177 * the new migration mle.  this way we can hold with the rule
3178 * of having only one mle for a given lock name at all times. */
3179static int dlm_add_migration_mle(struct dlm_ctxt *dlm,
3180                                 struct dlm_lock_resource *res,
3181                                 struct dlm_master_list_entry *mle,
3182                                 struct dlm_master_list_entry **oldmle,
3183                                 const char *name, unsigned int namelen,
3184                                 u8 new_master, u8 master)
3185{
3186        int found;
3187        int ret = 0;
3188
3189        *oldmle = NULL;
3190
3191        assert_spin_locked(&dlm->spinlock);
3192        assert_spin_locked(&dlm->master_lock);
3193
3194        /* caller is responsible for any ref taken here on oldmle */
3195        found = dlm_find_mle(dlm, oldmle, (char *)name, namelen);
3196        if (found) {
3197                struct dlm_master_list_entry *tmp = *oldmle;
3198                spin_lock(&tmp->spinlock);
3199                if (tmp->type == DLM_MLE_MIGRATION) {
3200                        if (master == dlm->node_num) {
3201                                /* ah another process raced me to it */
3202                                mlog(0, "tried to migrate %.*s, but some "
3203                                     "process beat me to it\n",
3204                                     namelen, name);
3205                                spin_unlock(&tmp->spinlock);
3206                                return -EEXIST;
3207                        } else {
3208                                /* bad.  2 NODES are trying to migrate! */
3209                                mlog(ML_ERROR, "migration error  mle: "
3210                                     "master=%u new_master=%u // request: "
3211                                     "master=%u new_master=%u // "
3212                                     "lockres=%.*s\n",
3213                                     tmp->master, tmp->new_master,
3214                                     master, new_master,
3215                                     namelen, name);
3216                                BUG();
3217                        }
3218                } else {
3219                        /* this is essentially what assert_master does */
3220                        tmp->master = master;
3221                        atomic_set(&tmp->woken, 1);
3222                        wake_up(&tmp->wq);
3223                        /* remove it so that only one mle will be found */
3224                        __dlm_unlink_mle(dlm, tmp);
3225                        __dlm_mle_detach_hb_events(dlm, tmp);
3226                        if (tmp->type == DLM_MLE_MASTER) {
3227                                ret = DLM_MIGRATE_RESPONSE_MASTERY_REF;
3228                                mlog(0, "%s:%.*s: master=%u, newmaster=%u, "
3229                                                "telling master to get ref "
3230                                                "for cleared out mle during "
3231                                                "migration\n", dlm->name,
3232                                                namelen, name, master,
3233                                                new_master);
3234                        }
3235                }
3236                spin_unlock(&tmp->spinlock);
3237        }
3238
3239        /* now add a migration mle to the tail of the list */
3240        dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen);
3241        mle->new_master = new_master;
3242        /* the new master will be sending an assert master for this.
3243         * at that point we will get the refmap reference */
3244        mle->master = master;
3245        /* do this for consistency with other mle types */
3246        set_bit(new_master, mle->maybe_map);
3247        __dlm_insert_mle(dlm, mle);
3248
3249        return ret;
3250}
3251
3252/*
3253 * Sets the owner of the lockres, associated to the mle, to UNKNOWN
3254 */
3255static struct dlm_lock_resource *dlm_reset_mleres_owner(struct dlm_ctxt *dlm,
3256                                        struct dlm_master_list_entry *mle)
3257{
3258        struct dlm_lock_resource *res;
3259
3260        /* Find the lockres associated to the mle and set its owner to UNK */
3261        res = __dlm_lookup_lockres(dlm, mle->mname, mle->mnamelen,
3262                                   mle->mnamehash);
3263        if (res) {
3264                spin_unlock(&dlm->master_lock);
3265
3266                /* move lockres onto recovery list */
3267                spin_lock(&res->spinlock);
3268                dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN);
3269                dlm_move_lockres_to_recovery_list(dlm, res);
3270                spin_unlock(&res->spinlock);
3271                dlm_lockres_put(res);
3272
3273                /* about to get rid of mle, detach from heartbeat */
3274                __dlm_mle_detach_hb_events(dlm, mle);
3275
3276                /* dump the mle */
3277                spin_lock(&dlm->master_lock);
3278                __dlm_put_mle(mle);
3279                spin_unlock(&dlm->master_lock);
3280        }
3281
3282        return res;
3283}
3284
3285static void dlm_clean_migration_mle(struct dlm_ctxt *dlm,
3286                                    struct dlm_master_list_entry *mle)
3287{
3288        __dlm_mle_detach_hb_events(dlm, mle);
3289
3290        spin_lock(&mle->spinlock);
3291        __dlm_unlink_mle(dlm, mle);
3292        atomic_set(&mle->woken, 1);
3293        spin_unlock(&mle->spinlock);
3294
3295        wake_up(&mle->wq);
3296}
3297
3298static void dlm_clean_block_mle(struct dlm_ctxt *dlm,
3299                                struct dlm_master_list_entry *mle, u8 dead_node)
3300{
3301        int bit;
3302
3303        BUG_ON(mle->type != DLM_MLE_BLOCK);
3304
3305        spin_lock(&mle->spinlock);
3306        bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0);
3307        if (bit != dead_node) {
3308                mlog(0, "mle found, but dead node %u would not have been "
3309                     "master\n", dead_node);
3310                spin_unlock(&mle->spinlock);
3311        } else {
3312                /* Must drop the refcount by one since the assert_master will
3313                 * never arrive. This may result in the mle being unlinked and
3314                 * freed, but there may still be a process waiting in the
3315                 * dlmlock path which is fine. */
3316                mlog(0, "node %u was expected master\n", dead_node);
3317                atomic_set(&mle->woken, 1);
3318                spin_unlock(&mle->spinlock);
3319                wake_up(&mle->wq);
3320
3321                /* Do not need events any longer, so detach from heartbeat */
3322                __dlm_mle_detach_hb_events(dlm, mle);
3323                __dlm_put_mle(mle);
3324        }
3325}
3326
3327void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node)
3328{
3329        struct dlm_master_list_entry *mle;
3330        struct dlm_lock_resource *res;
3331        struct hlist_head *bucket;
3332        struct hlist_node *tmp;
3333        unsigned int i;
3334
3335        mlog(0, "dlm=%s, dead node=%u\n", dlm->name, dead_node);
3336top:
3337        assert_spin_locked(&dlm->spinlock);
3338
3339        /* clean the master list */
3340        spin_lock(&dlm->master_lock);
3341        for (i = 0; i < DLM_HASH_BUCKETS; i++) {
3342                bucket = dlm_master_hash(dlm, i);
3343                hlist_for_each_entry_safe(mle, tmp, bucket, master_hash_node) {
3344                        BUG_ON(mle->type != DLM_MLE_BLOCK &&
3345                               mle->type != DLM_MLE_MASTER &&
3346                               mle->type != DLM_MLE_MIGRATION);
3347
3348                        /* MASTER mles are initiated locally. The waiting
3349                         * process will notice the node map change shortly.
3350                         * Let that happen as normal. */
3351                        if (mle->type == DLM_MLE_MASTER)
3352                                continue;
3353
3354                        /* BLOCK mles are initiated by other nodes. Need to
3355                         * clean up if the dead node would have been the
3356                         * master. */
3357                        if (mle->type == DLM_MLE_BLOCK) {
3358                                dlm_clean_block_mle(dlm, mle, dead_node);
3359                                continue;
3360                        }
3361
3362                        /* Everything else is a MIGRATION mle */
3363
3364                        /* The rule for MIGRATION mles is that the master
3365                         * becomes UNKNOWN if *either* the original or the new
3366                         * master dies. All UNKNOWN lockres' are sent to
3367                         * whichever node becomes the recovery master. The new
3368                         * master is responsible for determining if there is
3369                         * still a master for this lockres, or if he needs to
3370                         * take over mastery. Either way, this node should
3371                         * expect another message to resolve this. */
3372
3373                        if (mle->master != dead_node &&
3374                            mle->new_master != dead_node)
3375                                continue;
3376
3377                        if (mle->new_master == dead_node && mle->inuse) {
3378                                mlog(ML_NOTICE, "%s: target %u died during "
3379                                                "migration from %u, the MLE is "
3380                                                "still keep used, ignore it!\n",
3381                                                dlm->name, dead_node,
3382                                                mle->master);
3383                                continue;
3384                        }
3385
3386                        /* If we have reached this point, this mle needs to be
3387                         * removed from the list and freed. */
3388                        dlm_clean_migration_mle(dlm, mle);
3389
3390                        mlog(0, "%s: node %u died during migration from "
3391                             "%u to %u!\n", dlm->name, dead_node, mle->master,
3392                             mle->new_master);
3393
3394                        /* If we find a lockres associated with the mle, we've
3395                         * hit this rare case that messes up our lock ordering.
3396                         * If so, we need to drop the master lock so that we can
3397                         * take the lockres lock, meaning that we will have to
3398                         * restart from the head of list. */
3399                        res = dlm_reset_mleres_owner(dlm, mle);
3400                        if (res)
3401                                /* restart */
3402                                goto top;
3403
3404                        /* This may be the last reference */
3405                        __dlm_put_mle(mle);
3406                }
3407        }
3408        spin_unlock(&dlm->master_lock);
3409}
3410
3411int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
3412                         u8 old_master)
3413{
3414        struct dlm_node_iter iter;
3415        int ret = 0;
3416
3417        spin_lock(&dlm->spinlock);
3418        dlm_node_iter_init(dlm->domain_map, &iter);
3419        clear_bit(old_master, iter.node_map);
3420        clear_bit(dlm->node_num, iter.node_map);
3421        spin_unlock(&dlm->spinlock);
3422
3423        /* ownership of the lockres is changing.  account for the
3424         * mastery reference here since old_master will briefly have
3425         * a reference after the migration completes */
3426        spin_lock(&res->spinlock);
3427        dlm_lockres_set_refmap_bit(dlm, res, old_master);
3428        spin_unlock(&res->spinlock);
3429
3430        mlog(0, "now time to do a migrate request to other nodes\n");
3431        ret = dlm_do_migrate_request(dlm, res, old_master,
3432                                     dlm->node_num, &iter);
3433        if (ret < 0) {
3434                mlog_errno(ret);
3435                goto leave;
3436        }
3437
3438        mlog(0, "doing assert master of %.*s to all except the original node\n",
3439             res->lockname.len, res->lockname.name);
3440        /* this call now finishes out the nodemap
3441         * even if one or more nodes die */
3442        ret = dlm_do_assert_master(dlm, res, iter.node_map,
3443                                   DLM_ASSERT_MASTER_FINISH_MIGRATION);
3444        if (ret < 0) {
3445                /* no longer need to retry.  all living nodes contacted. */
3446                mlog_errno(ret);
3447                ret = 0;
3448        }
3449
3450        memset(iter.node_map, 0, sizeof(iter.node_map));
3451        set_bit(old_master, iter.node_map);
3452        mlog(0, "doing assert master of %.*s back to %u\n",
3453             res->lockname.len, res->lockname.name, old_master);
3454        ret = dlm_do_assert_master(dlm, res, iter.node_map,
3455                                   DLM_ASSERT_MASTER_FINISH_MIGRATION);
3456        if (ret < 0) {
3457                mlog(0, "assert master to original master failed "
3458                     "with %d.\n", ret);
3459                /* the only nonzero status here would be because of
3460                 * a dead original node.  we're done. */
3461                ret = 0;
3462        }
3463
3464        /* all done, set the owner, clear the flag */
3465        spin_lock(&res->spinlock);
3466        dlm_set_lockres_owner(dlm, res, dlm->node_num);
3467        res->state &= ~DLM_LOCK_RES_MIGRATING;
3468        spin_unlock(&res->spinlock);
3469        /* re-dirty it on the new master */
3470        dlm_kick_thread(dlm, res);
3471        wake_up(&res->wq);
3472leave:
3473        return ret;
3474}
3475
3476/*
3477 * LOCKRES AST REFCOUNT
3478 * this is integral to migration
3479 */
3480
3481/* for future intent to call an ast, reserve one ahead of time.
3482 * this should be called only after waiting on the lockres
3483 * with dlm_wait_on_lockres, and while still holding the
3484 * spinlock after the call. */
3485void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res)
3486{
3487        assert_spin_locked(&res->spinlock);
3488        if (res->state & DLM_LOCK_RES_MIGRATING) {
3489                __dlm_print_one_lock_resource(res);
3490        }
3491        BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3492
3493        atomic_inc(&res->asts_reserved);
3494}
3495
3496/*
3497 * used to drop the reserved ast, either because it went unused,
3498 * or because the ast/bast was actually called.
3499 *
3500 * also, if there is a pending migration on this lockres,
3501 * and this was the last pending ast on the lockres,
3502 * atomically set the MIGRATING flag before we drop the lock.
3503 * this is how we ensure that migration can proceed with no
3504 * asts in progress.  note that it is ok if the state of the
3505 * queues is such that a lock should be granted in the future
3506 * or that a bast should be fired, because the new master will
3507 * shuffle the lists on this lockres as soon as it is migrated.
3508 */
3509void dlm_lockres_release_ast(struct dlm_ctxt *dlm,
3510                             struct dlm_lock_resource *res)
3511{
3512        if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock))
3513                return;
3514
3515        if (!res->migration_pending) {
3516                spin_unlock(&res->spinlock);
3517                return;
3518        }
3519
3520        BUG_ON(res->state & DLM_LOCK_RES_MIGRATING);
3521        res->migration_pending = 0;
3522        res->state |= DLM_LOCK_RES_MIGRATING;
3523        spin_unlock(&res->spinlock);
3524        wake_up(&res->wq);
3525        wake_up(&dlm->migration_wq);
3526}
3527
3528void dlm_force_free_mles(struct dlm_ctxt *dlm)
3529{
3530        int i;
3531        struct hlist_head *bucket;
3532        struct dlm_master_list_entry *mle;
3533        struct hlist_node *tmp;
3534
3535        /*
3536         * We notified all other nodes that we are exiting the domain and
3537         * marked the dlm state to DLM_CTXT_LEAVING. If any mles are still
3538         * around we force free them and wake any processes that are waiting
3539         * on the mles
3540         */
3541        spin_lock(&dlm->spinlock);
3542        spin_lock(&dlm->master_lock);
3543
3544        BUG_ON(dlm->dlm_state != DLM_CTXT_LEAVING);
3545        BUG_ON((find_next_bit(dlm->domain_map, O2NM_MAX_NODES, 0) < O2NM_MAX_NODES));
3546
3547        for (i = 0; i < DLM_HASH_BUCKETS; i++) {
3548                bucket = dlm_master_hash(dlm, i);
3549                hlist_for_each_entry_safe(mle, tmp, bucket, master_hash_node) {
3550                        if (mle->type != DLM_MLE_BLOCK) {
3551                                mlog(ML_ERROR, "bad mle: %p\n", mle);
3552                                dlm_print_one_mle(mle);
3553                        }
3554                        atomic_set(&mle->woken, 1);
3555                        wake_up(&mle->wq);
3556
3557                        __dlm_unlink_mle(dlm, mle);
3558                        __dlm_mle_detach_hb_events(dlm, mle);
3559                        __dlm_put_mle(mle);
3560                }
3561        }
3562        spin_unlock(&dlm->master_lock);
3563        spin_unlock(&dlm->spinlock);
3564}
3565