drivers/md/md-cluster.c

   1 /*
   2  * Copyright (C) 2015, SUSE
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2, or (at your option)
   7  * any later version.
   8  *
   9  */
  10
  11
  12 #include <linux/module.h>
  13 #include <linux/dlm.h>
  14 #include <linux/sched.h>
  15 #include <linux/raid/md_p.h>
  16 #include "md.h"
  17 #include "bitmap.h"
  18 #include "md-cluster.h"
  19
  20 #define LVB_SIZE        64
  21 #define NEW_DEV_TIMEOUT 5000
  22
  23 struct dlm_lock_resource {
  24         dlm_lockspace_t *ls;
  25         struct dlm_lksb lksb;
  26         char *name; /* lock name. */
  27         uint32_t flags; /* flags to pass to dlm_lock() */
  28         struct completion completion; /* completion for synchronized locking */
  29         void (*bast)(void *arg, int mode); /* blocking AST function pointer*/
  30         struct mddev *mddev; /* pointing back to mddev. */
  31         int mode;
  32 };
  33
  34 struct suspend_info {
  35         int slot;
  36         sector_t lo;
  37         sector_t hi;
  38         struct list_head list;
  39 };
  40
  41 struct resync_info {
  42         __le64 lo;
  43         __le64 hi;
  44 };
  45
  46 /* md_cluster_info flags */
  47 #define         MD_CLUSTER_WAITING_FOR_NEWDISK          1
  48 #define         MD_CLUSTER_SUSPEND_READ_BALANCING       2
  49 #define         MD_CLUSTER_BEGIN_JOIN_CLUSTER           3
  50
  51 /* Lock the send communication. This is done through
  52  * bit manipulation as opposed to a mutex in order to
  53  * accomodate lock and hold. See next comment.
  54  */
  55 #define         MD_CLUSTER_SEND_LOCK                    4
  56 /* If cluster operations (such as adding a disk) must lock the
  57  * communication channel, so as to perform extra operations
  58  * (update metadata) and no other operation is allowed on the
  59  * MD. Token needs to be locked and held until the operation
  60  * completes witha md_update_sb(), which would eventually release
  61  * the lock.
  62  */
  63 #define         MD_CLUSTER_SEND_LOCKED_ALREADY          5
  64
  65
  66 struct md_cluster_info {
  67         /* dlm lock space and resources for clustered raid. */
  68         dlm_lockspace_t *lockspace;
  69         int slot_number;
  70         struct completion completion;
  71         struct mutex recv_mutex;
  72         struct dlm_lock_resource *bitmap_lockres;
  73         struct dlm_lock_resource **other_bitmap_lockres;
  74         struct dlm_lock_resource *resync_lockres;
  75         struct list_head suspend_list;
  76         spinlock_t suspend_lock;
  77         struct md_thread *recovery_thread;
  78         unsigned long recovery_map;
  79         /* communication loc resources */
  80         struct dlm_lock_resource *ack_lockres;
  81         struct dlm_lock_resource *message_lockres;
  82         struct dlm_lock_resource *token_lockres;
  83         struct dlm_lock_resource *no_new_dev_lockres;
  84         struct md_thread *recv_thread;
  85         struct completion newdisk_completion;
  86         wait_queue_head_t wait;
  87         unsigned long state;
  88 };
  89
  90 enum msg_type {
  91         METADATA_UPDATED = 0,
  92         RESYNCING,
  93         NEWDISK,
  94         REMOVE,
  95         RE_ADD,
  96         BITMAP_NEEDS_SYNC,
  97 };
  98
  99 struct cluster_msg {
 100         __le32 type;
 101         __le32 slot;
 102         /* TODO: Unionize this for smaller footprint */
 103         __le64 low;
 104         __le64 high;
 105         char uuid[16];
 106         __le32 raid_slot;
 107 };
 108
 109 static void sync_ast(void *arg)
 110 {
 111         struct dlm_lock_resource *res;
 112
 113         res = arg;
 114         complete(&res->completion);
 115 }
 116
 117 static int dlm_lock_sync(struct dlm_lock_resource *res, int mode)
 118 {
 119         int ret = 0;
 120
 121         ret = dlm_lock(res->ls, mode, &res->lksb,
 122                         res->flags, res->name, strlen(res->name),
 123                         0, sync_ast, res, res->bast);
 124         if (ret)
 125                 return ret;
 126         wait_for_completion(&res->completion);
 127         if (res->lksb.sb_status == 0)
 128                 res->mode = mode;
 129         return res->lksb.sb_status;
 130 }
 131
 132 static int dlm_unlock_sync(struct dlm_lock_resource *res)
 133 {
 134         return dlm_lock_sync(res, DLM_LOCK_NL);
 135 }
 136
 137 static struct dlm_lock_resource *lockres_init(struct mddev *mddev,
 138                 char *name, void (*bastfn)(void *arg, int mode), int with_lvb)
 139 {
 140         struct dlm_lock_resource *res = NULL;
 141         int ret, namelen;
 142         struct md_cluster_info *cinfo = mddev->cluster_info;
 143
 144         res = kzalloc(sizeof(struct dlm_lock_resource), GFP_KERNEL);
 145         if (!res)
 146                 return NULL;
 147         init_completion(&res->completion);
 148         res->ls = cinfo->lockspace;
 149         res->mddev = mddev;
 150         res->mode = DLM_LOCK_IV;
 151         namelen = strlen(name);
 152         res->name = kzalloc(namelen + 1, GFP_KERNEL);
 153         if (!res->name) {
 154                 pr_err("md-cluster: Unable to allocate resource name for resource %s\n", name);
 155                 goto out_err;
 156         }
 157         strlcpy(res->name, name, namelen + 1);
 158         if (with_lvb) {
 159                 res->lksb.sb_lvbptr = kzalloc(LVB_SIZE, GFP_KERNEL);
 160                 if (!res->lksb.sb_lvbptr) {
 161                         pr_err("md-cluster: Unable to allocate LVB for resource %s\n", name);
 162                         goto out_err;
 163                 }
 164                 res->flags = DLM_LKF_VALBLK;
 165         }
 166
 167         if (bastfn)
 168                 res->bast = bastfn;
 169
 170         res->flags |= DLM_LKF_EXPEDITE;
 171
 172         ret = dlm_lock_sync(res, DLM_LOCK_NL);
 173         if (ret) {
 174                 pr_err("md-cluster: Unable to lock NL on new lock resource %s\n", name);
 175                 goto out_err;
 176         }
 177         res->flags &= ~DLM_LKF_EXPEDITE;
 178         res->flags |= DLM_LKF_CONVERT;
 179
 180         return res;
 181 out_err:
 182         kfree(res->lksb.sb_lvbptr);
 183         kfree(res->name);
 184         kfree(res);
 185         return NULL;
 186 }
 187
 188 static void lockres_free(struct dlm_lock_resource *res)
 189 {
 190         int ret;
 191
 192         if (!res)
 193                 return;
 194
 195         /* cancel a lock request or a conversion request that is blocked */
 196         res->flags |= DLM_LKF_CANCEL;
 197 retry:
 198         ret = dlm_unlock(res->ls, res->lksb.sb_lkid, 0, &res->lksb, res);
 199         if (unlikely(ret != 0)) {
 200                 pr_info("%s: failed to unlock %s return %d\n", __func__, res->name, ret);
 201
 202                 /* if a lock conversion is cancelled, then the lock is put
 203                  * back to grant queue, need to ensure it is unlocked */
 204                 if (ret == -DLM_ECANCEL)
 205                         goto retry;
 206         }
 207         res->flags &= ~DLM_LKF_CANCEL;
 208         wait_for_completion(&res->completion);
 209
 210         kfree(res->name);
 211         kfree(res->lksb.sb_lvbptr);
 212         kfree(res);
 213 }
 214
 215 static void add_resync_info(struct dlm_lock_resource *lockres,
 216                             sector_t lo, sector_t hi)
 217 {
 218         struct resync_info *ri;
 219
 220         ri = (struct resync_info *)lockres->lksb.sb_lvbptr;
 221         ri->lo = cpu_to_le64(lo);
 222         ri->hi = cpu_to_le64(hi);
 223 }
 224
 225 static struct suspend_info *read_resync_info(struct mddev *mddev, struct dlm_lock_resource *lockres)
 226 {
 227         struct resync_info ri;
 228         struct suspend_info *s = NULL;
 229         sector_t hi = 0;
 230
 231         dlm_lock_sync(lockres, DLM_LOCK_CR);
 232         memcpy(&ri, lockres->lksb.sb_lvbptr, sizeof(struct resync_info));
 233         hi = le64_to_cpu(ri.hi);
 234         if (hi > 0) {
 235                 s = kzalloc(sizeof(struct suspend_info), GFP_KERNEL);
 236                 if (!s)
 237                         goto out;
 238                 s->hi = hi;
 239                 s->lo = le64_to_cpu(ri.lo);
 240         }
 241         dlm_unlock_sync(lockres);
 242 out:
 243         return s;
 244 }
 245
 246 static void recover_bitmaps(struct md_thread *thread)
 247 {
 248         struct mddev *mddev = thread->mddev;
 249         struct md_cluster_info *cinfo = mddev->cluster_info;
 250         struct dlm_lock_resource *bm_lockres;
 251         char str[64];
 252         int slot, ret;
 253         struct suspend_info *s, *tmp;
 254         sector_t lo, hi;
 255
 256         while (cinfo->recovery_map) {
 257                 slot = fls64((u64)cinfo->recovery_map) - 1;
 258
 259                 /* Clear suspend_area associated with the bitmap */
 260                 spin_lock_irq(&cinfo->suspend_lock);
 261                 list_for_each_entry_safe(s, tmp, &cinfo->suspend_list, list)
 262                         if (slot == s->slot) {
 263                                 list_del(&s->list);
 264                                 kfree(s);
 265                         }
 266                 spin_unlock_irq(&cinfo->suspend_lock);
 267
 268                 snprintf(str, 64, "bitmap%04d", slot);
 269                 bm_lockres = lockres_init(mddev, str, NULL, 1);
 270                 if (!bm_lockres) {
 271                         pr_err("md-cluster: Cannot initialize bitmaps\n");
 272                         goto clear_bit;
 273                 }
 274
 275                 ret = dlm_lock_sync(bm_lockres, DLM_LOCK_PW);
 276                 if (ret) {
 277                         pr_err("md-cluster: Could not DLM lock %s: %d\n",
 278                                         str, ret);
 279                         goto clear_bit;
 280                 }
 281                 ret = bitmap_copy_from_slot(mddev, slot, &lo, &hi, true);
 282                 if (ret) {
 283                         pr_err("md-cluster: Could not copy data from bitmap %d\n", slot);
 284                         goto dlm_unlock;
 285                 }
 286                 if (hi > 0) {
 287                         /* TODO:Wait for current resync to get over */
 288                         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 289                         if (lo < mddev->recovery_cp)
 290                                 mddev->recovery_cp = lo;
 291                         md_check_recovery(mddev);
 292                 }
 293 dlm_unlock:
 294                 dlm_unlock_sync(bm_lockres);
 295 clear_bit:
 296                 clear_bit(slot, &cinfo->recovery_map);
 297         }
 298 }
 299
 300 static void recover_prep(void *arg)
 301 {
 302         struct mddev *mddev = arg;
 303         struct md_cluster_info *cinfo = mddev->cluster_info;
 304         set_bit(MD_CLUSTER_SUSPEND_READ_BALANCING, &cinfo->state);
 305 }
 306
 307 static void __recover_slot(struct mddev *mddev, int slot)
 308 {
 309         struct md_cluster_info *cinfo = mddev->cluster_info;
 310
 311         set_bit(slot, &cinfo->recovery_map);
 312         if (!cinfo->recovery_thread) {
 313                 cinfo->recovery_thread = md_register_thread(recover_bitmaps,
 314                                 mddev, "recover");
 315                 if (!cinfo->recovery_thread) {
 316                         pr_warn("md-cluster: Could not create recovery thread\n");
 317                         return;
 318                 }
 319         }
 320         md_wakeup_thread(cinfo->recovery_thread);
 321 }
 322
 323 static void recover_slot(void *arg, struct dlm_slot *slot)
 324 {
 325         struct mddev *mddev = arg;
 326         struct md_cluster_info *cinfo = mddev->cluster_info;
 327
 328         pr_info("md-cluster: %s Node %d/%d down. My slot: %d. Initiating recovery.\n",
 329                         mddev->bitmap_info.cluster_name,
 330                         slot->nodeid, slot->slot,
 331                         cinfo->slot_number);
 332         /* deduct one since dlm slot starts from one while the num of
 333          * cluster-md begins with 0 */
 334         __recover_slot(mddev, slot->slot - 1);
 335 }
 336
 337 static void recover_done(void *arg, struct dlm_slot *slots,
 338                 int num_slots, int our_slot,
 339                 uint32_t generation)
 340 {
 341         struct mddev *mddev = arg;
 342         struct md_cluster_info *cinfo = mddev->cluster_info;
 343
 344         cinfo->slot_number = our_slot;
 345         /* completion is only need to be complete when node join cluster,
 346          * it doesn't need to run during another node's failure */
 347         if (test_bit(MD_CLUSTER_BEGIN_JOIN_CLUSTER, &cinfo->state)) {
 348                 complete(&cinfo->completion);
 349                 clear_bit(MD_CLUSTER_BEGIN_JOIN_CLUSTER, &cinfo->state);
 350         }
 351         clear_bit(MD_CLUSTER_SUSPEND_READ_BALANCING, &cinfo->state);
 352 }
 353
 354 /* the ops is called when node join the cluster, and do lock recovery
 355  * if node failure occurs */
 356 static const struct dlm_lockspace_ops md_ls_ops = {
 357         .recover_prep = recover_prep,
 358         .recover_slot = recover_slot,
 359         .recover_done = recover_done,
 360 };
 361
 362 /*
 363  * The BAST function for the ack lock resource
 364  * This function wakes up the receive thread in
 365  * order to receive and process the message.
 366  */
 367 static void ack_bast(void *arg, int mode)
 368 {
 369         struct dlm_lock_resource *res = arg;
 370         struct md_cluster_info *cinfo = res->mddev->cluster_info;
 371
 372         if (mode == DLM_LOCK_EX)
 373                 md_wakeup_thread(cinfo->recv_thread);
 374 }
 375
 376 static void __remove_suspend_info(struct md_cluster_info *cinfo, int slot)
 377 {
 378         struct suspend_info *s, *tmp;
 379
 380         list_for_each_entry_safe(s, tmp, &cinfo->suspend_list, list)
 381                 if (slot == s->slot) {
 382                         list_del(&s->list);
 383                         kfree(s);
 384                         break;
 385                 }
 386 }
 387
 388 static void remove_suspend_info(struct mddev *mddev, int slot)
 389 {
 390         struct md_cluster_info *cinfo = mddev->cluster_info;
 391         spin_lock_irq(&cinfo->suspend_lock);
 392         __remove_suspend_info(cinfo, slot);
 393         spin_unlock_irq(&cinfo->suspend_lock);
 394         mddev->pers->quiesce(mddev, 2);
 395 }
 396
 397
 398 static void process_suspend_info(struct mddev *mddev,
 399                 int slot, sector_t lo, sector_t hi)
 400 {
 401         struct md_cluster_info *cinfo = mddev->cluster_info;
 402         struct suspend_info *s;
 403
 404         if (!hi) {
 405                 remove_suspend_info(mddev, slot);
 406                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 407                 md_wakeup_thread(mddev->thread);
 408                 return;
 409         }
 410         s = kzalloc(sizeof(struct suspend_info), GFP_KERNEL);
 411         if (!s)
 412                 return;
 413         s->slot = slot;
 414         s->lo = lo;
 415         s->hi = hi;
 416         mddev->pers->quiesce(mddev, 1);
 417         mddev->pers->quiesce(mddev, 0);
 418         spin_lock_irq(&cinfo->suspend_lock);
 419         /* Remove existing entry (if exists) before adding */
 420         __remove_suspend_info(cinfo, slot);
 421         list_add(&s->list, &cinfo->suspend_list);
 422         spin_unlock_irq(&cinfo->suspend_lock);
 423         mddev->pers->quiesce(mddev, 2);
 424 }
 425
 426 static void process_add_new_disk(struct mddev *mddev, struct cluster_msg *cmsg)
 427 {
 428         char disk_uuid[64];
 429         struct md_cluster_info *cinfo = mddev->cluster_info;
 430         char event_name[] = "EVENT=ADD_DEVICE";
 431         char raid_slot[16];
 432         char *envp[] = {event_name, disk_uuid, raid_slot, NULL};
 433         int len;
 434
 435         len = snprintf(disk_uuid, 64, "DEVICE_UUID=");
 436         sprintf(disk_uuid + len, "%pU", cmsg->uuid);
 437         snprintf(raid_slot, 16, "RAID_DISK=%d", le32_to_cpu(cmsg->raid_slot));
 438         pr_info("%s:%d Sending kobject change with %s and %s\n", __func__, __LINE__, disk_uuid, raid_slot);
 439         init_completion(&cinfo->newdisk_completion);
 440         set_bit(MD_CLUSTER_WAITING_FOR_NEWDISK, &cinfo->state);
 441         kobject_uevent_env(&disk_to_dev(mddev->gendisk)->kobj, KOBJ_CHANGE, envp);
 442         wait_for_completion_timeout(&cinfo->newdisk_completion,
 443                         NEW_DEV_TIMEOUT);
 444         clear_bit(MD_CLUSTER_WAITING_FOR_NEWDISK, &cinfo->state);
 445 }
 446
 447
 448 static void process_metadata_update(struct mddev *mddev, struct cluster_msg *msg)
 449 {
 450         struct md_cluster_info *cinfo = mddev->cluster_info;
 451         mddev->good_device_nr = le32_to_cpu(msg->raid_slot);
 452         set_bit(MD_RELOAD_SB, &mddev->flags);
 453         dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR);
 454         md_wakeup_thread(mddev->thread);
 455 }
 456
 457 static void process_remove_disk(struct mddev *mddev, struct cluster_msg *msg)
 458 {
 459         struct md_rdev *rdev = md_find_rdev_nr_rcu(mddev,
 460                                                    le32_to_cpu(msg->raid_slot));
 461
 462         if (rdev) {
 463                 set_bit(ClusterRemove, &rdev->flags);
 464                 set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 465                 md_wakeup_thread(mddev->thread);
 466         }
 467         else
 468                 pr_warn("%s: %d Could not find disk(%d) to REMOVE\n",
 469                         __func__, __LINE__, le32_to_cpu(msg->raid_slot));
 470 }
 471
 472 static void process_readd_disk(struct mddev *mddev, struct cluster_msg *msg)
 473 {
 474         struct md_rdev *rdev = md_find_rdev_nr_rcu(mddev,
 475                                                    le32_to_cpu(msg->raid_slot));
 476
 477         if (rdev && test_bit(Faulty, &rdev->flags))
 478                 clear_bit(Faulty, &rdev->flags);
 479         else
 480                 pr_warn("%s: %d Could not find disk(%d) which is faulty",
 481                         __func__, __LINE__, le32_to_cpu(msg->raid_slot));
 482 }
 483
 484 static void process_recvd_msg(struct mddev *mddev, struct cluster_msg *msg)
 485 {
 486         if (WARN(mddev->cluster_info->slot_number - 1 == le32_to_cpu(msg->slot),
 487                 "node %d received it's own msg\n", le32_to_cpu(msg->slot)))
 488                 return;
 489         switch (le32_to_cpu(msg->type)) {
 490         case METADATA_UPDATED:
 491                 process_metadata_update(mddev, msg);
 492                 break;
 493         case RESYNCING:
 494                 process_suspend_info(mddev, le32_to_cpu(msg->slot),
 495                                      le64_to_cpu(msg->low),
 496                                      le64_to_cpu(msg->high));
 497                 break;
 498         case NEWDISK:
 499                 process_add_new_disk(mddev, msg);
 500                 break;
 501         case REMOVE:
 502                 process_remove_disk(mddev, msg);
 503                 break;
 504         case RE_ADD:
 505                 process_readd_disk(mddev, msg);
 506                 break;
 507         case BITMAP_NEEDS_SYNC:
 508                 __recover_slot(mddev, le32_to_cpu(msg->slot));
 509                 break;
 510         default:
 511                 pr_warn("%s:%d Received unknown message from %d\n",
 512                         __func__, __LINE__, msg->slot);
 513         }
 514 }
 515
 516 /*
 517  * thread for receiving message
 518  */
 519 static void recv_daemon(struct md_thread *thread)
 520 {
 521         struct md_cluster_info *cinfo = thread->mddev->cluster_info;
 522         struct dlm_lock_resource *ack_lockres = cinfo->ack_lockres;
 523         struct dlm_lock_resource *message_lockres = cinfo->message_lockres;
 524         struct cluster_msg msg;
 525         int ret;
 526
 527         mutex_lock(&cinfo->recv_mutex);
 528         /*get CR on Message*/
 529         if (dlm_lock_sync(message_lockres, DLM_LOCK_CR)) {
 530                 pr_err("md/raid1:failed to get CR on MESSAGE\n");
 531                 mutex_unlock(&cinfo->recv_mutex);
 532                 return;
 533         }
 534
 535         /* read lvb and wake up thread to process this message_lockres */
 536         memcpy(&msg, message_lockres->lksb.sb_lvbptr, sizeof(struct cluster_msg));
 537         process_recvd_msg(thread->mddev, &msg);
 538
 539         /*release CR on ack_lockres*/
 540         ret = dlm_unlock_sync(ack_lockres);
 541         if (unlikely(ret != 0))
 542                 pr_info("unlock ack failed return %d\n", ret);
 543         /*up-convert to PR on message_lockres*/
 544         ret = dlm_lock_sync(message_lockres, DLM_LOCK_PR);
 545         if (unlikely(ret != 0))
 546                 pr_info("lock PR on msg failed return %d\n", ret);
 547         /*get CR on ack_lockres again*/
 548         ret = dlm_lock_sync(ack_lockres, DLM_LOCK_CR);
 549         if (unlikely(ret != 0))
 550                 pr_info("lock CR on ack failed return %d\n", ret);
 551         /*release CR on message_lockres*/
 552         ret = dlm_unlock_sync(message_lockres);
 553         if (unlikely(ret != 0))
 554                 pr_info("unlock msg failed return %d\n", ret);
 555         mutex_unlock(&cinfo->recv_mutex);
 556 }
 557
 558 /* lock_token()
 559  * Takes the lock on the TOKEN lock resource so no other
 560  * node can communicate while the operation is underway.
 561  */
 562 static int lock_token(struct md_cluster_info *cinfo)
 563 {
 564         int error;
 565
 566         error = dlm_lock_sync(cinfo->token_lockres, DLM_LOCK_EX);
 567         if (error)
 568                 pr_err("md-cluster(%s:%d): failed to get EX on TOKEN (%d)\n",
 569                                 __func__, __LINE__, error);
 570
 571         /* Lock the receive sequence */
 572         mutex_lock(&cinfo->recv_mutex);
 573         return error;
 574 }
 575
 576 /* lock_comm()
 577  * Sets the MD_CLUSTER_SEND_LOCK bit to lock the send channel.
 578  */
 579 static int lock_comm(struct md_cluster_info *cinfo)
 580 {
 581         wait_event(cinfo->wait,
 582                    !test_and_set_bit(MD_CLUSTER_SEND_LOCK, &cinfo->state));
 583
 584         return lock_token(cinfo);
 585 }
 586
 587 static void unlock_comm(struct md_cluster_info *cinfo)
 588 {
 589         WARN_ON(cinfo->token_lockres->mode != DLM_LOCK_EX);
 590         mutex_unlock(&cinfo->recv_mutex);
 591         dlm_unlock_sync(cinfo->token_lockres);
 592         clear_bit(MD_CLUSTER_SEND_LOCK, &cinfo->state);
 593         wake_up(&cinfo->wait);
 594 }
 595
 596 /* __sendmsg()
 597  * This function performs the actual sending of the message. This function is
 598  * usually called after performing the encompassing operation
 599  * The function:
 600  * 1. Grabs the message lockresource in EX mode
 601  * 2. Copies the message to the message LVB
 602  * 3. Downconverts message lockresource to CW
 603  * 4. Upconverts ack lock resource from CR to EX. This forces the BAST on other nodes
 604  *    and the other nodes read the message. The thread will wait here until all other
 605  *    nodes have released ack lock resource.
 606  * 5. Downconvert ack lockresource to CR
 607  */
 608 static int __sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg)
 609 {
 610         int error;
 611         int slot = cinfo->slot_number - 1;
 612
 613         cmsg->slot = cpu_to_le32(slot);
 614         /*get EX on Message*/
 615         error = dlm_lock_sync(cinfo->message_lockres, DLM_LOCK_EX);
 616         if (error) {
 617                 pr_err("md-cluster: failed to get EX on MESSAGE (%d)\n", error);
 618                 goto failed_message;
 619         }
 620
 621         memcpy(cinfo->message_lockres->lksb.sb_lvbptr, (void *)cmsg,
 622                         sizeof(struct cluster_msg));
 623         /*down-convert EX to CW on Message*/
 624         error = dlm_lock_sync(cinfo->message_lockres, DLM_LOCK_CW);
 625         if (error) {
 626                 pr_err("md-cluster: failed to convert EX to CW on MESSAGE(%d)\n",
 627                                 error);
 628                 goto failed_ack;
 629         }
 630
 631         /*up-convert CR to EX on Ack*/
 632         error = dlm_lock_sync(cinfo->ack_lockres, DLM_LOCK_EX);
 633         if (error) {
 634                 pr_err("md-cluster: failed to convert CR to EX on ACK(%d)\n",
 635                                 error);
 636                 goto failed_ack;
 637         }
 638
 639         /*down-convert EX to CR on Ack*/
 640         error = dlm_lock_sync(cinfo->ack_lockres, DLM_LOCK_CR);
 641         if (error) {
 642                 pr_err("md-cluster: failed to convert EX to CR on ACK(%d)\n",
 643                                 error);
 644                 goto failed_ack;
 645         }
 646
 647 failed_ack:
 648         error = dlm_unlock_sync(cinfo->message_lockres);
 649         if (unlikely(error != 0)) {
 650                 pr_err("md-cluster: failed convert to NL on MESSAGE(%d)\n",
 651                         error);
 652                 /* in case the message can't be released due to some reason */
 653                 goto failed_ack;
 654         }
 655 failed_message:
 656         return error;
 657 }
 658
 659 static int sendmsg(struct md_cluster_info *cinfo, struct cluster_msg *cmsg)
 660 {
 661         int ret;
 662
 663         lock_comm(cinfo);
 664         ret = __sendmsg(cinfo, cmsg);
 665         unlock_comm(cinfo);
 666         return ret;
 667 }
 668
 669 static int gather_all_resync_info(struct mddev *mddev, int total_slots)
 670 {
 671         struct md_cluster_info *cinfo = mddev->cluster_info;
 672         int i, ret = 0;
 673         struct dlm_lock_resource *bm_lockres;
 674         struct suspend_info *s;
 675         char str[64];
 676         sector_t lo, hi;
 677
 678
 679         for (i = 0; i < total_slots; i++) {
 680                 memset(str, '\0', 64);
 681                 snprintf(str, 64, "bitmap%04d", i);
 682                 bm_lockres = lockres_init(mddev, str, NULL, 1);
 683                 if (!bm_lockres)
 684                         return -ENOMEM;
 685                 if (i == (cinfo->slot_number - 1))
 686                         continue;
 687
 688                 bm_lockres->flags |= DLM_LKF_NOQUEUE;
 689                 ret = dlm_lock_sync(bm_lockres, DLM_LOCK_PW);
 690                 if (ret == -EAGAIN) {
 691                         memset(bm_lockres->lksb.sb_lvbptr, '\0', LVB_SIZE);
 692                         s = read_resync_info(mddev, bm_lockres);
 693                         if (s) {
 694                                 pr_info("%s:%d Resync[%llu..%llu] in progress on %d\n",
 695                                                 __func__, __LINE__,
 696                                                 (unsigned long long) s->lo,
 697                                                 (unsigned long long) s->hi, i);
 698                                 spin_lock_irq(&cinfo->suspend_lock);
 699                                 s->slot = i;
 700                                 list_add(&s->list, &cinfo->suspend_list);
 701                                 spin_unlock_irq(&cinfo->suspend_lock);
 702                         }
 703                         ret = 0;
 704                         lockres_free(bm_lockres);
 705                         continue;
 706                 }
 707                 if (ret) {
 708                         lockres_free(bm_lockres);
 709                         goto out;
 710                 }
 711
 712                 /* Read the disk bitmap sb and check if it needs recovery */
 713                 ret = bitmap_copy_from_slot(mddev, i, &lo, &hi, false);
 714                 if (ret) {
 715                         pr_warn("md-cluster: Could not gather bitmaps from slot %d", i);
 716                         lockres_free(bm_lockres);
 717                         continue;
 718                 }
 719                 if ((hi > 0) && (lo < mddev->recovery_cp)) {
 720                         set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
 721                         mddev->recovery_cp = lo;
 722                         md_check_recovery(mddev);
 723                 }
 724
 725                 dlm_unlock_sync(bm_lockres);
 726                 lockres_free(bm_lockres);
 727         }
 728 out:
 729         return ret;
 730 }
 731
 732 static int join(struct mddev *mddev, int nodes)
 733 {
 734         struct md_cluster_info *cinfo;
 735         int ret, ops_rv;
 736         char str[64];
 737
 738         cinfo = kzalloc(sizeof(struct md_cluster_info), GFP_KERNEL);
 739         if (!cinfo)
 740                 return -ENOMEM;
 741
 742         INIT_LIST_HEAD(&cinfo->suspend_list);
 743         spin_lock_init(&cinfo->suspend_lock);
 744         init_completion(&cinfo->completion);
 745         set_bit(MD_CLUSTER_BEGIN_JOIN_CLUSTER, &cinfo->state);
 746         init_waitqueue_head(&cinfo->wait);
 747         mutex_init(&cinfo->recv_mutex);
 748
 749         mddev->cluster_info = cinfo;
 750
 751         memset(str, 0, 64);
 752         sprintf(str, "%pU", mddev->uuid);
 753         ret = dlm_new_lockspace(str, mddev->bitmap_info.cluster_name,
 754                                 DLM_LSFL_FS, LVB_SIZE,
 755                                 &md_ls_ops, mddev, &ops_rv, &cinfo->lockspace);
 756         if (ret)
 757                 goto err;
 758         wait_for_completion(&cinfo->completion);
 759         if (nodes < cinfo->slot_number) {
 760                 pr_err("md-cluster: Slot allotted(%d) is greater than available slots(%d).",
 761                         cinfo->slot_number, nodes);
 762                 ret = -ERANGE;
 763                 goto err;
 764         }
 765         /* Initiate the communication resources */
 766         ret = -ENOMEM;
 767         cinfo->recv_thread = md_register_thread(recv_daemon, mddev, "cluster_recv");
 768         if (!cinfo->recv_thread) {
 769                 pr_err("md-cluster: cannot allocate memory for recv_thread!\n");
 770                 goto err;
 771         }
 772         cinfo->message_lockres = lockres_init(mddev, "message", NULL, 1);
 773         if (!cinfo->message_lockres)
 774                 goto err;
 775         cinfo->token_lockres = lockres_init(mddev, "token", NULL, 0);
 776         if (!cinfo->token_lockres)
 777                 goto err;
 778         cinfo->ack_lockres = lockres_init(mddev, "ack", ack_bast, 0);
 779         if (!cinfo->ack_lockres)
 780                 goto err;
 781         cinfo->no_new_dev_lockres = lockres_init(mddev, "no-new-dev", NULL, 0);
 782         if (!cinfo->no_new_dev_lockres)
 783                 goto err;
 784
 785         /* get sync CR lock on ACK. */
 786         if (dlm_lock_sync(cinfo->ack_lockres, DLM_LOCK_CR))
 787                 pr_err("md-cluster: failed to get a sync CR lock on ACK!(%d)\n",
 788                                 ret);
 789         /* get sync CR lock on no-new-dev. */
 790         if (dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR))
 791                 pr_err("md-cluster: failed to get a sync CR lock on no-new-dev!(%d)\n", ret);
 792
 793
 794         pr_info("md-cluster: Joined cluster %s slot %d\n", str, cinfo->slot_number);
 795         snprintf(str, 64, "bitmap%04d", cinfo->slot_number - 1);
 796         cinfo->bitmap_lockres = lockres_init(mddev, str, NULL, 1);
 797         if (!cinfo->bitmap_lockres)
 798                 goto err;
 799         if (dlm_lock_sync(cinfo->bitmap_lockres, DLM_LOCK_PW)) {
 800                 pr_err("Failed to get bitmap lock\n");
 801                 ret = -EINVAL;
 802                 goto err;
 803         }
 804
 805         cinfo->resync_lockres = lockres_init(mddev, "resync", NULL, 0);
 806         if (!cinfo->resync_lockres)
 807                 goto err;
 808
 809         ret = gather_all_resync_info(mddev, nodes);
 810         if (ret)
 811                 goto err;
 812
 813         return 0;
 814 err:
 815         lockres_free(cinfo->message_lockres);
 816         lockres_free(cinfo->token_lockres);
 817         lockres_free(cinfo->ack_lockres);
 818         lockres_free(cinfo->no_new_dev_lockres);
 819         lockres_free(cinfo->resync_lockres);
 820         lockres_free(cinfo->bitmap_lockres);
 821         if (cinfo->lockspace)
 822                 dlm_release_lockspace(cinfo->lockspace, 2);
 823         mddev->cluster_info = NULL;
 824         kfree(cinfo);
 825         return ret;
 826 }
 827
 828 static void resync_bitmap(struct mddev *mddev)
 829 {
 830         struct md_cluster_info *cinfo = mddev->cluster_info;
 831         struct cluster_msg cmsg = {0};
 832         int err;
 833
 834         cmsg.type = cpu_to_le32(BITMAP_NEEDS_SYNC);
 835         err = sendmsg(cinfo, &cmsg);
 836         if (err)
 837                 pr_err("%s:%d: failed to send BITMAP_NEEDS_SYNC message (%d)\n",
 838                         __func__, __LINE__, err);
 839 }
 840
 841 static void unlock_all_bitmaps(struct mddev *mddev);
 842 static int leave(struct mddev *mddev)
 843 {
 844         struct md_cluster_info *cinfo = mddev->cluster_info;
 845
 846         if (!cinfo)
 847                 return 0;
 848
 849         /* BITMAP_NEEDS_SYNC message should be sent when node
 850          * is leaving the cluster with dirty bitmap, also we
 851          * can only deliver it when dlm connection is available */
 852         if (cinfo->slot_number > 0 && mddev->recovery_cp != MaxSector)
 853                 resync_bitmap(mddev);
 854
 855         md_unregister_thread(&cinfo->recovery_thread);
 856         md_unregister_thread(&cinfo->recv_thread);
 857         lockres_free(cinfo->message_lockres);
 858         lockres_free(cinfo->token_lockres);
 859         lockres_free(cinfo->ack_lockres);
 860         lockres_free(cinfo->no_new_dev_lockres);
 861         lockres_free(cinfo->bitmap_lockres);
 862         unlock_all_bitmaps(mddev);
 863         dlm_release_lockspace(cinfo->lockspace, 2);
 864         return 0;
 865 }
 866
 867 /* slot_number(): Returns the MD slot number to use
 868  * DLM starts the slot numbers from 1, wheras cluster-md
 869  * wants the number to be from zero, so we deduct one
 870  */
 871 static int slot_number(struct mddev *mddev)
 872 {
 873         struct md_cluster_info *cinfo = mddev->cluster_info;
 874
 875         return cinfo->slot_number - 1;
 876 }
 877
 878 /*
 879  * Check if the communication is already locked, else lock the communication
 880  * channel.
 881  * If it is already locked, token is in EX mode, and hence lock_token()
 882  * should not be called.
 883  */
 884 static int metadata_update_start(struct mddev *mddev)
 885 {
 886         struct md_cluster_info *cinfo = mddev->cluster_info;
 887
 888         wait_event(cinfo->wait,
 889                    !test_and_set_bit(MD_CLUSTER_SEND_LOCK, &cinfo->state) ||
 890                    test_and_clear_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state));
 891
 892         /* If token is already locked, return 0 */
 893         if (cinfo->token_lockres->mode == DLM_LOCK_EX)
 894                 return 0;
 895
 896         return lock_token(cinfo);
 897 }
 898
 899 static int metadata_update_finish(struct mddev *mddev)
 900 {
 901         struct md_cluster_info *cinfo = mddev->cluster_info;
 902         struct cluster_msg cmsg;
 903         struct md_rdev *rdev;
 904         int ret = 0;
 905         int raid_slot = -1;
 906
 907         memset(&cmsg, 0, sizeof(cmsg));
 908         cmsg.type = cpu_to_le32(METADATA_UPDATED);
 909         /* Pick up a good active device number to send.
 910          */
 911         rdev_for_each(rdev, mddev)
 912                 if (rdev->raid_disk > -1 && !test_bit(Faulty, &rdev->flags)) {
 913                         raid_slot = rdev->desc_nr;
 914                         break;
 915                 }
 916         if (raid_slot >= 0) {
 917                 cmsg.raid_slot = cpu_to_le32(raid_slot);
 918                 ret = __sendmsg(cinfo, &cmsg);
 919         } else
 920                 pr_warn("md-cluster: No good device id found to send\n");
 921         clear_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
 922         unlock_comm(cinfo);
 923         return ret;
 924 }
 925
 926 static void metadata_update_cancel(struct mddev *mddev)
 927 {
 928         struct md_cluster_info *cinfo = mddev->cluster_info;
 929         clear_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
 930         unlock_comm(cinfo);
 931 }
 932
 933 static int resync_start(struct mddev *mddev)
 934 {
 935         struct md_cluster_info *cinfo = mddev->cluster_info;
 936         cinfo->resync_lockres->flags |= DLM_LKF_NOQUEUE;
 937         return dlm_lock_sync(cinfo->resync_lockres, DLM_LOCK_EX);
 938 }
 939
 940 static int resync_info_update(struct mddev *mddev, sector_t lo, sector_t hi)
 941 {
 942         struct md_cluster_info *cinfo = mddev->cluster_info;
 943         struct resync_info ri;
 944         struct cluster_msg cmsg = {0};
 945
 946         /* do not send zero again, if we have sent before */
 947         if (hi == 0) {
 948                 memcpy(&ri, cinfo->bitmap_lockres->lksb.sb_lvbptr, sizeof(struct resync_info));
 949                 if (le64_to_cpu(ri.hi) == 0)
 950                         return 0;
 951         }
 952
 953         add_resync_info(cinfo->bitmap_lockres, lo, hi);
 954         /* Re-acquire the lock to refresh LVB */
 955         dlm_lock_sync(cinfo->bitmap_lockres, DLM_LOCK_PW);
 956         cmsg.type = cpu_to_le32(RESYNCING);
 957         cmsg.low = cpu_to_le64(lo);
 958         cmsg.high = cpu_to_le64(hi);
 959
 960         return sendmsg(cinfo, &cmsg);
 961 }
 962
 963 static int resync_finish(struct mddev *mddev)
 964 {
 965         struct md_cluster_info *cinfo = mddev->cluster_info;
 966         cinfo->resync_lockres->flags &= ~DLM_LKF_NOQUEUE;
 967         dlm_unlock_sync(cinfo->resync_lockres);
 968         return resync_info_update(mddev, 0, 0);
 969 }
 970
 971 static int area_resyncing(struct mddev *mddev, int direction,
 972                 sector_t lo, sector_t hi)
 973 {
 974         struct md_cluster_info *cinfo = mddev->cluster_info;
 975         int ret = 0;
 976         struct suspend_info *s;
 977
 978         if ((direction == READ) &&
 979                 test_bit(MD_CLUSTER_SUSPEND_READ_BALANCING, &cinfo->state))
 980                 return 1;
 981
 982         spin_lock_irq(&cinfo->suspend_lock);
 983         if (list_empty(&cinfo->suspend_list))
 984                 goto out;
 985         list_for_each_entry(s, &cinfo->suspend_list, list)
 986                 if (hi > s->lo && lo < s->hi) {
 987                         ret = 1;
 988                         break;
 989                 }
 990 out:
 991         spin_unlock_irq(&cinfo->suspend_lock);
 992         return ret;
 993 }
 994
 995 /* add_new_disk() - initiates a disk add
 996  * However, if this fails before writing md_update_sb(),
 997  * add_new_disk_cancel() must be called to release token lock
 998  */
 999 static int add_new_disk(struct mddev *mddev, struct md_rdev *rdev)
1000 {
1001         struct md_cluster_info *cinfo = mddev->cluster_info;
1002         struct cluster_msg cmsg;
1003         int ret = 0;
1004         struct mdp_superblock_1 *sb = page_address(rdev->sb_page);
1005         char *uuid = sb->device_uuid;
1006
1007         memset(&cmsg, 0, sizeof(cmsg));
1008         cmsg.type = cpu_to_le32(NEWDISK);
1009         memcpy(cmsg.uuid, uuid, 16);
1010         cmsg.raid_slot = cpu_to_le32(rdev->desc_nr);
1011         lock_comm(cinfo);
1012         ret = __sendmsg(cinfo, &cmsg);
1013         if (ret)
1014                 return ret;
1015         cinfo->no_new_dev_lockres->flags |= DLM_LKF_NOQUEUE;
1016         ret = dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_EX);
1017         cinfo->no_new_dev_lockres->flags &= ~DLM_LKF_NOQUEUE;
1018         /* Some node does not "see" the device */
1019         if (ret == -EAGAIN)
1020                 ret = -ENOENT;
1021         if (ret)
1022                 unlock_comm(cinfo);
1023         else {
1024                 dlm_lock_sync(cinfo->no_new_dev_lockres, DLM_LOCK_CR);
1025                 /* Since MD_CHANGE_DEVS will be set in add_bound_rdev which
1026                  * will run soon after add_new_disk, the below path will be
1027                  * invoked:
1028                  *   md_wakeup_thread(mddev->thread)
1029                  *      -> conf->thread (raid1d)
1030                  *      -> md_check_recovery -> md_update_sb
1031                  *      -> metadata_update_start/finish
1032                  * MD_CLUSTER_SEND_LOCKED_ALREADY will be cleared eventually.
1033                  *
1034                  * For other failure cases, metadata_update_cancel and
1035                  * add_new_disk_cancel also clear below bit as well.
1036                  * */
1037                 set_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
1038                 wake_up(&cinfo->wait);
1039         }
1040         return ret;
1041 }
1042
1043 static void add_new_disk_cancel(struct mddev *mddev)
1044 {
1045         struct md_cluster_info *cinfo = mddev->cluster_info;
1046         clear_bit(MD_CLUSTER_SEND_LOCKED_ALREADY, &cinfo->state);
1047         unlock_comm(cinfo);
1048 }
1049
1050 static int new_disk_ack(struct mddev *mddev, bool ack)
1051 {
1052         struct md_cluster_info *cinfo = mddev->cluster_info;
1053
1054         if (!test_bit(MD_CLUSTER_WAITING_FOR_NEWDISK, &cinfo->state)) {
1055                 pr_warn("md-cluster(%s): Spurious cluster confirmation\n", mdname(mddev));
1056                 return -EINVAL;
1057         }
1058
1059         if (ack)
1060                 dlm_unlock_sync(cinfo->no_new_dev_lockres);
1061         complete(&cinfo->newdisk_completion);
1062         return 0;
1063 }
1064
1065 static int remove_disk(struct mddev *mddev, struct md_rdev *rdev)
1066 {
1067         struct cluster_msg cmsg = {0};
1068         struct md_cluster_info *cinfo = mddev->cluster_info;
1069         cmsg.type = cpu_to_le32(REMOVE);
1070         cmsg.raid_slot = cpu_to_le32(rdev->desc_nr);
1071         return sendmsg(cinfo, &cmsg);
1072 }
1073
1074 static int lock_all_bitmaps(struct mddev *mddev)
1075 {
1076         int slot, my_slot, ret, held = 1, i = 0;
1077         char str[64];
1078         struct md_cluster_info *cinfo = mddev->cluster_info;
1079
1080         cinfo->other_bitmap_lockres = kzalloc((mddev->bitmap_info.nodes - 1) *
1081                                              sizeof(struct dlm_lock_resource *),
1082                                              GFP_KERNEL);
1083         if (!cinfo->other_bitmap_lockres) {
1084                 pr_err("md: can't alloc mem for other bitmap locks\n");
1085                 return 0;
1086         }
1087
1088         my_slot = slot_number(mddev);
1089         for (slot = 0; slot < mddev->bitmap_info.nodes; slot++) {
1090                 if (slot == my_slot)
1091                         continue;
1092
1093                 memset(str, '\0', 64);
1094                 snprintf(str, 64, "bitmap%04d", slot);
1095                 cinfo->other_bitmap_lockres[i] = lockres_init(mddev, str, NULL, 1);
1096                 if (!cinfo->other_bitmap_lockres[i])
1097                         return -ENOMEM;
1098
1099                 cinfo->other_bitmap_lockres[i]->flags |= DLM_LKF_NOQUEUE;
1100                 ret = dlm_lock_sync(cinfo->other_bitmap_lockres[i], DLM_LOCK_PW);
1101                 if (ret)
1102                         held = -1;
1103                 i++;
1104         }
1105
1106         return held;
1107 }
1108
1109 static void unlock_all_bitmaps(struct mddev *mddev)
1110 {
1111         struct md_cluster_info *cinfo = mddev->cluster_info;
1112         int i;
1113
1114         /* release other node's bitmap lock if they are existed */
1115         if (cinfo->other_bitmap_lockres) {
1116                 for (i = 0; i < mddev->bitmap_info.nodes - 1; i++) {
1117                         if (cinfo->other_bitmap_lockres[i]) {
1118                                 dlm_unlock_sync(cinfo->other_bitmap_lockres[i]);
1119                                 lockres_free(cinfo->other_bitmap_lockres[i]);
1120                         }
1121                 }
1122                 kfree(cinfo->other_bitmap_lockres);
1123         }
1124 }
1125
1126 static int gather_bitmaps(struct md_rdev *rdev)
1127 {
1128         int sn, err;
1129         sector_t lo, hi;
1130         struct cluster_msg cmsg = {0};
1131         struct mddev *mddev = rdev->mddev;
1132         struct md_cluster_info *cinfo = mddev->cluster_info;
1133
1134         cmsg.type = cpu_to_le32(RE_ADD);
1135         cmsg.raid_slot = cpu_to_le32(rdev->desc_nr);
1136         err = sendmsg(cinfo, &cmsg);
1137         if (err)
1138                 goto out;
1139
1140         for (sn = 0; sn < mddev->bitmap_info.nodes; sn++) {
1141                 if (sn == (cinfo->slot_number - 1))
1142                         continue;
1143                 err = bitmap_copy_from_slot(mddev, sn, &lo, &hi, false);
1144                 if (err) {
1145                         pr_warn("md-cluster: Could not gather bitmaps from slot %d", sn);
1146                         goto out;
1147                 }
1148                 if ((hi > 0) && (lo < mddev->recovery_cp))
1149                         mddev->recovery_cp = lo;
1150         }
1151 out:
1152         return err;
1153 }
1154
1155 static struct md_cluster_operations cluster_ops = {
1156         .join   = join,
1157         .leave  = leave,
1158         .slot_number = slot_number,
1159         .resync_start = resync_start,
1160         .resync_finish = resync_finish,
1161         .resync_info_update = resync_info_update,
1162         .metadata_update_start = metadata_update_start,
1163         .metadata_update_finish = metadata_update_finish,
1164         .metadata_update_cancel = metadata_update_cancel,
1165         .area_resyncing = area_resyncing,
1166         .add_new_disk = add_new_disk,
1167         .add_new_disk_cancel = add_new_disk_cancel,
1168         .new_disk_ack = new_disk_ack,
1169         .remove_disk = remove_disk,
1170         .gather_bitmaps = gather_bitmaps,
1171         .lock_all_bitmaps = lock_all_bitmaps,
1172         .unlock_all_bitmaps = unlock_all_bitmaps,
1173 };
1174
1175 static int __init cluster_init(void)
1176 {
1177         pr_warn("md-cluster: EXPERIMENTAL. Use with caution\n");
1178         pr_info("Registering Cluster MD functions\n");
1179         register_md_cluster_operations(&cluster_ops, THIS_MODULE);
1180         return 0;
1181 }
1182
1183 static void cluster_exit(void)
1184 {
1185         unregister_md_cluster_operations();
1186 }
1187
1188 module_init(cluster_init);
1189 module_exit(cluster_exit);
1190 MODULE_AUTHOR("SUSE");
1191 MODULE_LICENSE("GPL");
1192 MODULE_DESCRIPTION("Clustering support for MD");