drivers/block/drbd/drbd_actlog.c

   1 /*
   2    drbd_actlog.c
   3
   4    This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
   5
   6    Copyright (C) 2003-2008, LINBIT Information Technologies GmbH.
   7    Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>.
   8    Copyright (C) 2003-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
   9
  10    drbd is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 2, or (at your option)
  13    any later version.
  14
  15    drbd is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with drbd; see the file COPYING.  If not, write to
  22    the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  23
  24  */
  25
  26 #include <linux/slab.h>
  27 #include <linux/crc32c.h>
  28 #include <linux/drbd.h>
  29 #include <linux/drbd_limits.h>
  30 #include <linux/dynamic_debug.h>
  31 #include "drbd_int.h"
  32 #include "drbd_wrappers.h"
  33
  34
  35 enum al_transaction_types {
  36         AL_TR_UPDATE = 0,
  37         AL_TR_INITIALIZED = 0xffff
  38 };
  39 /* all fields on disc in big endian */
  40 struct __packed al_transaction_on_disk {
  41         /* don't we all like magic */
  42         __be32  magic;
  43
  44         /* to identify the most recent transaction block
  45          * in the on disk ring buffer */
  46         __be32  tr_number;
  47
  48         /* checksum on the full 4k block, with this field set to 0. */
  49         __be32  crc32c;
  50
  51         /* type of transaction, special transaction types like:
  52          * purge-all, set-all-idle, set-all-active, ... to-be-defined
  53          * see also enum al_transaction_types */
  54         __be16  transaction_type;
  55
  56         /* we currently allow only a few thousand extents,
  57          * so 16bit will be enough for the slot number. */
  58
  59         /* how many updates in this transaction */
  60         __be16  n_updates;
  61
  62         /* maximum slot number, "al-extents" in drbd.conf speak.
  63          * Having this in each transaction should make reconfiguration
  64          * of that parameter easier. */
  65         __be16  context_size;
  66
  67         /* slot number the context starts with */
  68         __be16  context_start_slot_nr;
  69
  70         /* Some reserved bytes.  Expected usage is a 64bit counter of
  71          * sectors-written since device creation, and other data generation tag
  72          * supporting usage */
  73         __be32  __reserved[4];
  74
  75         /* --- 36 byte used --- */
  76
  77         /* Reserve space for up to AL_UPDATES_PER_TRANSACTION changes
  78          * in one transaction, then use the remaining byte in the 4k block for
  79          * context information.  "Flexible" number of updates per transaction
  80          * does not help, as we have to account for the case when all update
  81          * slots are used anyways, so it would only complicate code without
  82          * additional benefit.
  83          */
  84         __be16  update_slot_nr[AL_UPDATES_PER_TRANSACTION];
  85
  86         /* but the extent number is 32bit, which at an extent size of 4 MiB
  87          * allows to cover device sizes of up to 2**54 Byte (16 PiB) */
  88         __be32  update_extent_nr[AL_UPDATES_PER_TRANSACTION];
  89
  90         /* --- 420 bytes used (36 + 64*6) --- */
  91
  92         /* 4096 - 420 = 3676 = 919 * 4 */
  93         __be32  context[AL_CONTEXT_PER_TRANSACTION];
  94 };
  95
  96 struct update_odbm_work {
  97         struct drbd_work w;
  98         unsigned int enr;
  99 };
 100
 101 struct update_al_work {
 102         struct drbd_work w;
 103         struct completion event;
 104         int err;
 105 };
 106
 107 static int al_write_transaction(struct drbd_conf *mdev);
 108
 109 void *drbd_md_get_buffer(struct drbd_conf *mdev)
 110 {
 111         int r;
 112
 113         wait_event(mdev->misc_wait,
 114                    (r = atomic_cmpxchg(&mdev->md_io_in_use, 0, 1)) == 0 ||
 115                    mdev->state.disk <= D_FAILED);
 116
 117         return r ? NULL : page_address(mdev->md_io_page);
 118 }
 119
 120 void drbd_md_put_buffer(struct drbd_conf *mdev)
 121 {
 122         if (atomic_dec_and_test(&mdev->md_io_in_use))
 123                 wake_up(&mdev->misc_wait);
 124 }
 125
 126 static bool md_io_allowed(struct drbd_conf *mdev)
 127 {
 128         enum drbd_disk_state ds = mdev->state.disk;
 129         return ds >= D_NEGOTIATING || ds == D_ATTACHING;
 130 }
 131
 132 void wait_until_done_or_disk_failure(struct drbd_conf *mdev, unsigned int *done)
 133 {
 134         wait_event(mdev->misc_wait, *done || !md_io_allowed(mdev));
 135 }
 136
 137 static int _drbd_md_sync_page_io(struct drbd_conf *mdev,
 138                                  struct drbd_backing_dev *bdev,
 139                                  struct page *page, sector_t sector,
 140                                  int rw, int size)
 141 {
 142         struct bio *bio;
 143         int err;
 144
 145         mdev->md_io.done = 0;
 146         mdev->md_io.error = -ENODEV;
 147
 148         if ((rw & WRITE) && !test_bit(MD_NO_FUA, &mdev->flags))
 149                 rw |= REQ_FUA | REQ_FLUSH;
 150         rw |= REQ_SYNC;
 151
 152         bio = bio_alloc_drbd(GFP_NOIO);
 153         bio->bi_bdev = bdev->md_bdev;
 154         bio->bi_sector = sector;
 155         err = -EIO;
 156         if (bio_add_page(bio, page, size, 0) != size)
 157                 goto out;
 158         bio->bi_private = &mdev->md_io;
 159         bio->bi_end_io = drbd_md_io_complete;
 160         bio->bi_rw = rw;
 161
 162         if (!get_ldev_if_state(mdev, D_ATTACHING)) {  /* Corresponding put_ldev in drbd_md_io_complete() */
 163                 dev_err(DEV, "ASSERT FAILED: get_ldev_if_state() == 1 in _drbd_md_sync_page_io()\n");
 164                 err = -ENODEV;
 165                 goto out;
 166         }
 167
 168         bio_get(bio); /* one bio_put() is in the completion handler */
 169         atomic_inc(&mdev->md_io_in_use); /* drbd_md_put_buffer() is in the completion handler */
 170         if (drbd_insert_fault(mdev, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
 171                 bio_endio(bio, -EIO);
 172         else
 173                 submit_bio(rw, bio);
 174         wait_until_done_or_disk_failure(mdev, &mdev->md_io.done);
 175         if (bio_flagged(bio, BIO_UPTODATE))
 176                 err = mdev->md_io.error;
 177
 178  out:
 179         bio_put(bio);
 180         return err;
 181 }
 182
 183 int drbd_md_sync_page_io(struct drbd_conf *mdev, struct drbd_backing_dev *bdev,
 184                          sector_t sector, int rw)
 185 {
 186         int err;
 187         struct page *iop = mdev->md_io_page;
 188
 189         D_ASSERT(atomic_read(&mdev->md_io_in_use) == 1);
 190
 191         BUG_ON(!bdev->md_bdev);
 192
 193         dev_dbg(DEV, "meta_data io: %s [%d]:%s(,%llus,%s)\n",
 194              current->comm, current->pid, __func__,
 195              (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
 196
 197         if (sector < drbd_md_first_sector(bdev) ||
 198             sector + 7 > drbd_md_last_sector(bdev))
 199                 dev_alert(DEV, "%s [%d]:%s(,%llus,%s) out of range md access!\n",
 200                      current->comm, current->pid, __func__,
 201                      (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
 202
 203         err = _drbd_md_sync_page_io(mdev, bdev, iop, sector, rw, MD_BLOCK_SIZE);
 204         if (err) {
 205                 dev_err(DEV, "drbd_md_sync_page_io(,%llus,%s) failed!\n",
 206                     (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
 207         }
 208         return err;
 209 }
 210
 211 static struct lc_element *_al_get(struct drbd_conf *mdev, unsigned int enr)
 212 {
 213         struct lc_element *al_ext;
 214         struct lc_element *tmp;
 215         int wake;
 216
 217         spin_lock_irq(&mdev->al_lock);
 218         tmp = lc_find(mdev->resync, enr/AL_EXT_PER_BM_SECT);
 219         if (unlikely(tmp != NULL)) {
 220                 struct bm_extent  *bm_ext = lc_entry(tmp, struct bm_extent, lce);
 221                 if (test_bit(BME_NO_WRITES, &bm_ext->flags)) {
 222                         wake = !test_and_set_bit(BME_PRIORITY, &bm_ext->flags);
 223                         spin_unlock_irq(&mdev->al_lock);
 224                         if (wake)
 225                                 wake_up(&mdev->al_wait);
 226                         return NULL;
 227                 }
 228         }
 229         al_ext = lc_get(mdev->act_log, enr);
 230         spin_unlock_irq(&mdev->al_lock);
 231         return al_ext;
 232 }
 233
 234 void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i)
 235 {
 236         /* for bios crossing activity log extent boundaries,
 237          * we may need to activate two extents in one go */
 238         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 239         unsigned last = (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 240         unsigned enr;
 241         bool locked = false;
 242
 243
 244         D_ASSERT(atomic_read(&mdev->local_cnt) > 0);
 245
 246         for (enr = first; enr <= last; enr++)
 247                 wait_event(mdev->al_wait, _al_get(mdev, enr) != NULL);
 248
 249         /* Serialize multiple transactions.
 250          * This uses test_and_set_bit, memory barrier is implicit.
 251          */
 252         wait_event(mdev->al_wait,
 253                         mdev->act_log->pending_changes == 0 ||
 254                         (locked = lc_try_lock_for_transaction(mdev->act_log)));
 255
 256         if (locked) {
 257                 /* drbd_al_write_transaction(mdev,al_ext,enr);
 258                  * recurses into generic_make_request(), which
 259                  * disallows recursion, bios being serialized on the
 260                  * current->bio_tail list now.
 261                  * we have to delegate updates to the activity log
 262                  * to the worker thread. */
 263
 264                 /* Double check: it may have been committed by someone else,
 265                  * while we have been waiting for the lock. */
 266                 if (mdev->act_log->pending_changes) {
 267                         int err;
 268                         err = al_write_transaction(mdev);
 269                         mdev->al_writ_cnt++;
 270
 271                         spin_lock_irq(&mdev->al_lock);
 272                         /* FIXME
 273                         if (err)
 274                                 we need an "lc_cancel" here;
 275                         */
 276                         lc_committed(mdev->act_log);
 277                         spin_unlock_irq(&mdev->al_lock);
 278                 }
 279                 lc_unlock(mdev->act_log);
 280                 wake_up(&mdev->al_wait);
 281         }
 282 }
 283
 284 void drbd_al_complete_io(struct drbd_conf *mdev, struct drbd_interval *i)
 285 {
 286         /* for bios crossing activity log extent boundaries,
 287          * we may need to activate two extents in one go */
 288         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 289         unsigned last = (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 290         unsigned enr;
 291         struct lc_element *extent;
 292         unsigned long flags;
 293         bool wake = false;
 294
 295         spin_lock_irqsave(&mdev->al_lock, flags);
 296
 297         for (enr = first; enr <= last; enr++) {
 298                 extent = lc_find(mdev->act_log, enr);
 299                 if (!extent) {
 300                         dev_err(DEV, "al_complete_io() called on inactive extent %u\n", enr);
 301                         continue;
 302                 }
 303                 if (lc_put(mdev->act_log, extent) == 0)
 304                         wake = true;
 305         }
 306         spin_unlock_irqrestore(&mdev->al_lock, flags);
 307         wake_up(&mdev->al_wait);
 308 }
 309
 310 #if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
 311 /* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
 312  * are still coupled, or assume too much about their relation.
 313  * Code below will not work if this is violated.
 314  * Will be cleaned up with some followup patch.
 315  */
 316 # error FIXME
 317 #endif
 318
 319 static unsigned int al_extent_to_bm_page(unsigned int al_enr)
 320 {
 321         return al_enr >>
 322                 /* bit to page */
 323                 ((PAGE_SHIFT + 3) -
 324                 /* al extent number to bit */
 325                  (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
 326 }
 327
 328 static unsigned int rs_extent_to_bm_page(unsigned int rs_enr)
 329 {
 330         return rs_enr >>
 331                 /* bit to page */
 332                 ((PAGE_SHIFT + 3) -
 333                 /* resync extent number to bit */
 334                  (BM_EXT_SHIFT - BM_BLOCK_SHIFT));
 335 }
 336
 337 static int
 338 _al_write_transaction(struct drbd_conf *mdev)
 339 {
 340         struct al_transaction_on_disk *buffer;
 341         struct lc_element *e;
 342         sector_t sector;
 343         int i, mx;
 344         unsigned extent_nr;
 345         unsigned crc = 0;
 346         int err = 0;
 347
 348         if (!get_ldev(mdev)) {
 349                 dev_err(DEV, "disk is %s, cannot start al transaction\n",
 350                         drbd_disk_str(mdev->state.disk));
 351                 return -EIO;
 352         }
 353
 354         /* The bitmap write may have failed, causing a state change. */
 355         if (mdev->state.disk < D_INCONSISTENT) {
 356                 dev_err(DEV,
 357                         "disk is %s, cannot write al transaction\n",
 358                         drbd_disk_str(mdev->state.disk));
 359                 put_ldev(mdev);
 360                 return -EIO;
 361         }
 362
 363         buffer = drbd_md_get_buffer(mdev); /* protects md_io_buffer, al_tr_cycle, ... */
 364         if (!buffer) {
 365                 dev_err(DEV, "disk failed while waiting for md_io buffer\n");
 366                 put_ldev(mdev);
 367                 return -ENODEV;
 368         }
 369
 370         memset(buffer, 0, sizeof(*buffer));
 371         buffer->magic = cpu_to_be32(DRBD_AL_MAGIC);
 372         buffer->tr_number = cpu_to_be32(mdev->al_tr_number);
 373
 374         i = 0;
 375
 376         /* Even though no one can start to change this list
 377          * once we set the LC_LOCKED -- from drbd_al_begin_io(),
 378          * lc_try_lock_for_transaction() --, someone may still
 379          * be in the process of changing it. */
 380         spin_lock_irq(&mdev->al_lock);
 381         list_for_each_entry(e, &mdev->act_log->to_be_changed, list) {
 382                 if (i == AL_UPDATES_PER_TRANSACTION) {
 383                         i++;
 384                         break;
 385                 }
 386                 buffer->update_slot_nr[i] = cpu_to_be16(e->lc_index);
 387                 buffer->update_extent_nr[i] = cpu_to_be32(e->lc_new_number);
 388                 if (e->lc_number != LC_FREE)
 389                         drbd_bm_mark_for_writeout(mdev,
 390                                         al_extent_to_bm_page(e->lc_number));
 391                 i++;
 392         }
 393         spin_unlock_irq(&mdev->al_lock);
 394         BUG_ON(i > AL_UPDATES_PER_TRANSACTION);
 395
 396         buffer->n_updates = cpu_to_be16(i);
 397         for ( ; i < AL_UPDATES_PER_TRANSACTION; i++) {
 398                 buffer->update_slot_nr[i] = cpu_to_be16(-1);
 399                 buffer->update_extent_nr[i] = cpu_to_be32(LC_FREE);
 400         }
 401
 402         buffer->context_size = cpu_to_be16(mdev->act_log->nr_elements);
 403         buffer->context_start_slot_nr = cpu_to_be16(mdev->al_tr_cycle);
 404
 405         mx = min_t(int, AL_CONTEXT_PER_TRANSACTION,
 406                    mdev->act_log->nr_elements - mdev->al_tr_cycle);
 407         for (i = 0; i < mx; i++) {
 408                 unsigned idx = mdev->al_tr_cycle + i;
 409                 extent_nr = lc_element_by_index(mdev->act_log, idx)->lc_number;
 410                 buffer->context[i] = cpu_to_be32(extent_nr);
 411         }
 412         for (; i < AL_CONTEXT_PER_TRANSACTION; i++)
 413                 buffer->context[i] = cpu_to_be32(LC_FREE);
 414
 415         mdev->al_tr_cycle += AL_CONTEXT_PER_TRANSACTION;
 416         if (mdev->al_tr_cycle >= mdev->act_log->nr_elements)
 417                 mdev->al_tr_cycle = 0;
 418
 419         sector =  mdev->ldev->md.md_offset
 420                 + mdev->ldev->md.al_offset
 421                 + mdev->al_tr_pos * (MD_BLOCK_SIZE>>9);
 422
 423         crc = crc32c(0, buffer, 4096);
 424         buffer->crc32c = cpu_to_be32(crc);
 425
 426         if (drbd_bm_write_hinted(mdev))
 427                 err = -EIO;
 428                 /* drbd_chk_io_error done already */
 429         else if (drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)) {
 430                 err = -EIO;
 431                 drbd_chk_io_error(mdev, 1, true);
 432         } else {
 433                 /* advance ringbuffer position and transaction counter */
 434                 mdev->al_tr_pos = (mdev->al_tr_pos + 1) % (MD_AL_SECTORS*512/MD_BLOCK_SIZE);
 435                 mdev->al_tr_number++;
 436         }
 437
 438         drbd_md_put_buffer(mdev);
 439         put_ldev(mdev);
 440
 441         return err;
 442 }
 443
 444
 445 static int w_al_write_transaction(struct drbd_work *w, int unused)
 446 {
 447         struct update_al_work *aw = container_of(w, struct update_al_work, w);
 448         struct drbd_conf *mdev = w->mdev;
 449         int err;
 450
 451         err = _al_write_transaction(mdev);
 452         aw->err = err;
 453         complete(&aw->event);
 454
 455         return err != -EIO ? err : 0;
 456 }
 457
 458 /* Calls from worker context (see w_restart_disk_io()) need to write the
 459    transaction directly. Others came through generic_make_request(),
 460    those need to delegate it to the worker. */
 461 static int al_write_transaction(struct drbd_conf *mdev)
 462 {
 463         struct update_al_work al_work;
 464
 465         if (current == mdev->tconn->worker.task)
 466                 return _al_write_transaction(mdev);
 467
 468         init_completion(&al_work.event);
 469         al_work.w.cb = w_al_write_transaction;
 470         al_work.w.mdev = mdev;
 471         drbd_queue_work_front(&mdev->tconn->data.work, &al_work.w);
 472         wait_for_completion(&al_work.event);
 473
 474         return al_work.err;
 475 }
 476
 477 static int _try_lc_del(struct drbd_conf *mdev, struct lc_element *al_ext)
 478 {
 479         int rv;
 480
 481         spin_lock_irq(&mdev->al_lock);
 482         rv = (al_ext->refcnt == 0);
 483         if (likely(rv))
 484                 lc_del(mdev->act_log, al_ext);
 485         spin_unlock_irq(&mdev->al_lock);
 486
 487         return rv;
 488 }
 489
 490 /**
 491  * drbd_al_shrink() - Removes all active extents form the activity log
 492  * @mdev:       DRBD device.
 493  *
 494  * Removes all active extents form the activity log, waiting until
 495  * the reference count of each entry dropped to 0 first, of course.
 496  *
 497  * You need to lock mdev->act_log with lc_try_lock() / lc_unlock()
 498  */
 499 void drbd_al_shrink(struct drbd_conf *mdev)
 500 {
 501         struct lc_element *al_ext;
 502         int i;
 503
 504         D_ASSERT(test_bit(__LC_LOCKED, &mdev->act_log->flags));
 505
 506         for (i = 0; i < mdev->act_log->nr_elements; i++) {
 507                 al_ext = lc_element_by_index(mdev->act_log, i);
 508                 if (al_ext->lc_number == LC_FREE)
 509                         continue;
 510                 wait_event(mdev->al_wait, _try_lc_del(mdev, al_ext));
 511         }
 512
 513         wake_up(&mdev->al_wait);
 514 }
 515
 516 static int w_update_odbm(struct drbd_work *w, int unused)
 517 {
 518         struct update_odbm_work *udw = container_of(w, struct update_odbm_work, w);
 519         struct drbd_conf *mdev = w->mdev;
 520         struct sib_info sib = { .sib_reason = SIB_SYNC_PROGRESS, };
 521
 522         if (!get_ldev(mdev)) {
 523                 if (__ratelimit(&drbd_ratelimit_state))
 524                         dev_warn(DEV, "Can not update on disk bitmap, local IO disabled.\n");
 525                 kfree(udw);
 526                 return 0;
 527         }
 528
 529         drbd_bm_write_page(mdev, rs_extent_to_bm_page(udw->enr));
 530         put_ldev(mdev);
 531
 532         kfree(udw);
 533
 534         if (drbd_bm_total_weight(mdev) <= mdev->rs_failed) {
 535                 switch (mdev->state.conn) {
 536                 case C_SYNC_SOURCE:  case C_SYNC_TARGET:
 537                 case C_PAUSED_SYNC_S: case C_PAUSED_SYNC_T:
 538                         drbd_resync_finished(mdev);
 539                 default:
 540                         /* nothing to do */
 541                         break;
 542                 }
 543         }
 544         drbd_bcast_event(mdev, &sib);
 545
 546         return 0;
 547 }
 548
 549
 550 /* ATTENTION. The AL's extents are 4MB each, while the extents in the
 551  * resync LRU-cache are 16MB each.
 552  * The caller of this function has to hold an get_ldev() reference.
 553  *
 554  * TODO will be obsoleted once we have a caching lru of the on disk bitmap
 555  */
 556 static void drbd_try_clear_on_disk_bm(struct drbd_conf *mdev, sector_t sector,
 557                                       int count, int success)
 558 {
 559         struct lc_element *e;
 560         struct update_odbm_work *udw;
 561
 562         unsigned int enr;
 563
 564         D_ASSERT(atomic_read(&mdev->local_cnt));
 565
 566         /* I simply assume that a sector/size pair never crosses
 567          * a 16 MB extent border. (Currently this is true...) */
 568         enr = BM_SECT_TO_EXT(sector);
 569
 570         e = lc_get(mdev->resync, enr);
 571         if (e) {
 572                 struct bm_extent *ext = lc_entry(e, struct bm_extent, lce);
 573                 if (ext->lce.lc_number == enr) {
 574                         if (success)
 575                                 ext->rs_left -= count;
 576                         else
 577                                 ext->rs_failed += count;
 578                         if (ext->rs_left < ext->rs_failed) {
 579                                 dev_err(DEV, "BAD! sector=%llus enr=%u rs_left=%d "
 580                                     "rs_failed=%d count=%d\n",
 581                                      (unsigned long long)sector,
 582                                      ext->lce.lc_number, ext->rs_left,
 583                                      ext->rs_failed, count);
 584                                 dump_stack();
 585
 586                                 lc_put(mdev->resync, &ext->lce);
 587                                 conn_request_state(mdev->tconn, NS(conn, C_DISCONNECTING), CS_HARD);
 588                                 return;
 589                         }
 590                 } else {
 591                         /* Normally this element should be in the cache,
 592                          * since drbd_rs_begin_io() pulled it already in.
 593                          *
 594                          * But maybe an application write finished, and we set
 595                          * something outside the resync lru_cache in sync.
 596                          */
 597                         int rs_left = drbd_bm_e_weight(mdev, enr);
 598                         if (ext->flags != 0) {
 599                                 dev_warn(DEV, "changing resync lce: %d[%u;%02lx]"
 600                                      " -> %d[%u;00]\n",
 601                                      ext->lce.lc_number, ext->rs_left,
 602                                      ext->flags, enr, rs_left);
 603                                 ext->flags = 0;
 604                         }
 605                         if (ext->rs_failed) {
 606                                 dev_warn(DEV, "Kicking resync_lru element enr=%u "
 607                                      "out with rs_failed=%d\n",
 608                                      ext->lce.lc_number, ext->rs_failed);
 609                         }
 610                         ext->rs_left = rs_left;
 611                         ext->rs_failed = success ? 0 : count;
 612                         /* we don't keep a persistent log of the resync lru,
 613                          * we can commit any change right away. */
 614                         lc_committed(mdev->resync);
 615                 }
 616                 lc_put(mdev->resync, &ext->lce);
 617                 /* no race, we are within the al_lock! */
 618
 619                 if (ext->rs_left == ext->rs_failed) {
 620                         ext->rs_failed = 0;
 621
 622                         udw = kmalloc(sizeof(*udw), GFP_ATOMIC);
 623                         if (udw) {
 624                                 udw->enr = ext->lce.lc_number;
 625                                 udw->w.cb = w_update_odbm;
 626                                 udw->w.mdev = mdev;
 627                                 drbd_queue_work_front(&mdev->tconn->data.work, &udw->w);
 628                         } else {
 629                                 dev_warn(DEV, "Could not kmalloc an udw\n");
 630                         }
 631                 }
 632         } else {
 633                 dev_err(DEV, "lc_get() failed! locked=%d/%d flags=%lu\n",
 634                     mdev->resync_locked,
 635                     mdev->resync->nr_elements,
 636                     mdev->resync->flags);
 637         }
 638 }
 639
 640 void drbd_advance_rs_marks(struct drbd_conf *mdev, unsigned long still_to_go)
 641 {
 642         unsigned long now = jiffies;
 643         unsigned long last = mdev->rs_mark_time[mdev->rs_last_mark];
 644         int next = (mdev->rs_last_mark + 1) % DRBD_SYNC_MARKS;
 645         if (time_after_eq(now, last + DRBD_SYNC_MARK_STEP)) {
 646                 if (mdev->rs_mark_left[mdev->rs_last_mark] != still_to_go &&
 647                     mdev->state.conn != C_PAUSED_SYNC_T &&
 648                     mdev->state.conn != C_PAUSED_SYNC_S) {
 649                         mdev->rs_mark_time[next] = now;
 650                         mdev->rs_mark_left[next] = still_to_go;
 651                         mdev->rs_last_mark = next;
 652                 }
 653         }
 654 }
 655
 656 /* clear the bit corresponding to the piece of storage in question:
 657  * size byte of data starting from sector.  Only clear a bits of the affected
 658  * one ore more _aligned_ BM_BLOCK_SIZE blocks.
 659  *
 660  * called by worker on C_SYNC_TARGET and receiver on SyncSource.
 661  *
 662  */
 663 void __drbd_set_in_sync(struct drbd_conf *mdev, sector_t sector, int size,
 664                        const char *file, const unsigned int line)
 665 {
 666         /* Is called from worker and receiver context _only_ */
 667         unsigned long sbnr, ebnr, lbnr;
 668         unsigned long count = 0;
 669         sector_t esector, nr_sectors;
 670         int wake_up = 0;
 671         unsigned long flags;
 672
 673         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
 674                 dev_err(DEV, "drbd_set_in_sync: sector=%llus size=%d nonsense!\n",
 675                                 (unsigned long long)sector, size);
 676                 return;
 677         }
 678         nr_sectors = drbd_get_capacity(mdev->this_bdev);
 679         esector = sector + (size >> 9) - 1;
 680
 681         if (!expect(sector < nr_sectors))
 682                 return;
 683         if (!expect(esector < nr_sectors))
 684                 esector = nr_sectors - 1;
 685
 686         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
 687
 688         /* we clear it (in sync).
 689          * round up start sector, round down end sector.  we make sure we only
 690          * clear full, aligned, BM_BLOCK_SIZE (4K) blocks */
 691         if (unlikely(esector < BM_SECT_PER_BIT-1))
 692                 return;
 693         if (unlikely(esector == (nr_sectors-1)))
 694                 ebnr = lbnr;
 695         else
 696                 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
 697         sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
 698
 699         if (sbnr > ebnr)
 700                 return;
 701
 702         /*
 703          * ok, (capacity & 7) != 0 sometimes, but who cares...
 704          * we count rs_{total,left} in bits, not sectors.
 705          */
 706         count = drbd_bm_clear_bits(mdev, sbnr, ebnr);
 707         if (count && get_ldev(mdev)) {
 708                 drbd_advance_rs_marks(mdev, drbd_bm_total_weight(mdev));
 709                 spin_lock_irqsave(&mdev->al_lock, flags);
 710                 drbd_try_clear_on_disk_bm(mdev, sector, count, true);
 711                 spin_unlock_irqrestore(&mdev->al_lock, flags);
 712
 713                 /* just wake_up unconditional now, various lc_chaged(),
 714                  * lc_put() in drbd_try_clear_on_disk_bm(). */
 715                 wake_up = 1;
 716                 put_ldev(mdev);
 717         }
 718         if (wake_up)
 719                 wake_up(&mdev->al_wait);
 720 }
 721
 722 /*
 723  * this is intended to set one request worth of data out of sync.
 724  * affects at least 1 bit,
 725  * and at most 1+DRBD_MAX_BIO_SIZE/BM_BLOCK_SIZE bits.
 726  *
 727  * called by tl_clear and drbd_send_dblock (==drbd_make_request).
 728  * so this can be _any_ process.
 729  */
 730 int __drbd_set_out_of_sync(struct drbd_conf *mdev, sector_t sector, int size,
 731                             const char *file, const unsigned int line)
 732 {
 733         unsigned long sbnr, ebnr, lbnr, flags;
 734         sector_t esector, nr_sectors;
 735         unsigned int enr, count = 0;
 736         struct lc_element *e;
 737
 738         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
 739                 dev_err(DEV, "sector: %llus, size: %d\n",
 740                         (unsigned long long)sector, size);
 741                 return 0;
 742         }
 743
 744         if (!get_ldev(mdev))
 745                 return 0; /* no disk, no metadata, no bitmap to set bits in */
 746
 747         nr_sectors = drbd_get_capacity(mdev->this_bdev);
 748         esector = sector + (size >> 9) - 1;
 749
 750         if (!expect(sector < nr_sectors))
 751                 goto out;
 752         if (!expect(esector < nr_sectors))
 753                 esector = nr_sectors - 1;
 754
 755         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
 756
 757         /* we set it out of sync,
 758          * we do not need to round anything here */
 759         sbnr = BM_SECT_TO_BIT(sector);
 760         ebnr = BM_SECT_TO_BIT(esector);
 761
 762         /* ok, (capacity & 7) != 0 sometimes, but who cares...
 763          * we count rs_{total,left} in bits, not sectors.  */
 764         spin_lock_irqsave(&mdev->al_lock, flags);
 765         count = drbd_bm_set_bits(mdev, sbnr, ebnr);
 766
 767         enr = BM_SECT_TO_EXT(sector);
 768         e = lc_find(mdev->resync, enr);
 769         if (e)
 770                 lc_entry(e, struct bm_extent, lce)->rs_left += count;
 771         spin_unlock_irqrestore(&mdev->al_lock, flags);
 772
 773 out:
 774         put_ldev(mdev);
 775
 776         return count;
 777 }
 778
 779 static
 780 struct bm_extent *_bme_get(struct drbd_conf *mdev, unsigned int enr)
 781 {
 782         struct lc_element *e;
 783         struct bm_extent *bm_ext;
 784         int wakeup = 0;
 785         unsigned long rs_flags;
 786
 787         spin_lock_irq(&mdev->al_lock);
 788         if (mdev->resync_locked > mdev->resync->nr_elements/2) {
 789                 spin_unlock_irq(&mdev->al_lock);
 790                 return NULL;
 791         }
 792         e = lc_get(mdev->resync, enr);
 793         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
 794         if (bm_ext) {
 795                 if (bm_ext->lce.lc_number != enr) {
 796                         bm_ext->rs_left = drbd_bm_e_weight(mdev, enr);
 797                         bm_ext->rs_failed = 0;
 798                         lc_committed(mdev->resync);
 799                         wakeup = 1;
 800                 }
 801                 if (bm_ext->lce.refcnt == 1)
 802                         mdev->resync_locked++;
 803                 set_bit(BME_NO_WRITES, &bm_ext->flags);
 804         }
 805         rs_flags = mdev->resync->flags;
 806         spin_unlock_irq(&mdev->al_lock);
 807         if (wakeup)
 808                 wake_up(&mdev->al_wait);
 809
 810         if (!bm_ext) {
 811                 if (rs_flags & LC_STARVING)
 812                         dev_warn(DEV, "Have to wait for element"
 813                              " (resync LRU too small?)\n");
 814                 BUG_ON(rs_flags & LC_LOCKED);
 815         }
 816
 817         return bm_ext;
 818 }
 819
 820 static int _is_in_al(struct drbd_conf *mdev, unsigned int enr)
 821 {
 822         int rv;
 823
 824         spin_lock_irq(&mdev->al_lock);
 825         rv = lc_is_used(mdev->act_log, enr);
 826         spin_unlock_irq(&mdev->al_lock);
 827
 828         return rv;
 829 }
 830
 831 /**
 832  * drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED
 833  * @mdev:       DRBD device.
 834  * @sector:     The sector number.
 835  *
 836  * This functions sleeps on al_wait. Returns 0 on success, -EINTR if interrupted.
 837  */
 838 int drbd_rs_begin_io(struct drbd_conf *mdev, sector_t sector)
 839 {
 840         unsigned int enr = BM_SECT_TO_EXT(sector);
 841         struct bm_extent *bm_ext;
 842         int i, sig;
 843         int sa = 200; /* Step aside 200 times, then grab the extent and let app-IO wait.
 844                          200 times -> 20 seconds. */
 845
 846 retry:
 847         sig = wait_event_interruptible(mdev->al_wait,
 848                         (bm_ext = _bme_get(mdev, enr)));
 849         if (sig)
 850                 return -EINTR;
 851
 852         if (test_bit(BME_LOCKED, &bm_ext->flags))
 853                 return 0;
 854
 855         for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
 856                 sig = wait_event_interruptible(mdev->al_wait,
 857                                                !_is_in_al(mdev, enr * AL_EXT_PER_BM_SECT + i) ||
 858                                                test_bit(BME_PRIORITY, &bm_ext->flags));
 859
 860                 if (sig || (test_bit(BME_PRIORITY, &bm_ext->flags) && sa)) {
 861                         spin_lock_irq(&mdev->al_lock);
 862                         if (lc_put(mdev->resync, &bm_ext->lce) == 0) {
 863                                 bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */
 864                                 mdev->resync_locked--;
 865                                 wake_up(&mdev->al_wait);
 866                         }
 867                         spin_unlock_irq(&mdev->al_lock);
 868                         if (sig)
 869                                 return -EINTR;
 870                         if (schedule_timeout_interruptible(HZ/10))
 871                                 return -EINTR;
 872                         if (sa && --sa == 0)
 873                                 dev_warn(DEV,"drbd_rs_begin_io() stepped aside for 20sec."
 874                                          "Resync stalled?\n");
 875                         goto retry;
 876                 }
 877         }
 878         set_bit(BME_LOCKED, &bm_ext->flags);
 879         return 0;
 880 }
 881
 882 /**
 883  * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
 884  * @mdev:       DRBD device.
 885  * @sector:     The sector number.
 886  *
 887  * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
 888  * tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN
 889  * if there is still application IO going on in this area.
 890  */
 891 int drbd_try_rs_begin_io(struct drbd_conf *mdev, sector_t sector)
 892 {
 893         unsigned int enr = BM_SECT_TO_EXT(sector);
 894         const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT;
 895         struct lc_element *e;
 896         struct bm_extent *bm_ext;
 897         int i;
 898
 899         spin_lock_irq(&mdev->al_lock);
 900         if (mdev->resync_wenr != LC_FREE && mdev->resync_wenr != enr) {
 901                 /* in case you have very heavy scattered io, it may
 902                  * stall the syncer undefined if we give up the ref count
 903                  * when we try again and requeue.
 904                  *
 905                  * if we don't give up the refcount, but the next time
 906                  * we are scheduled this extent has been "synced" by new
 907                  * application writes, we'd miss the lc_put on the
 908                  * extent we keep the refcount on.
 909                  * so we remembered which extent we had to try again, and
 910                  * if the next requested one is something else, we do
 911                  * the lc_put here...
 912                  * we also have to wake_up
 913                  */
 914                 e = lc_find(mdev->resync, mdev->resync_wenr);
 915                 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
 916                 if (bm_ext) {
 917                         D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
 918                         D_ASSERT(test_bit(BME_NO_WRITES, &bm_ext->flags));
 919                         clear_bit(BME_NO_WRITES, &bm_ext->flags);
 920                         mdev->resync_wenr = LC_FREE;
 921                         if (lc_put(mdev->resync, &bm_ext->lce) == 0)
 922                                 mdev->resync_locked--;
 923                         wake_up(&mdev->al_wait);
 924                 } else {
 925                         dev_alert(DEV, "LOGIC BUG\n");
 926                 }
 927         }
 928         /* TRY. */
 929         e = lc_try_get(mdev->resync, enr);
 930         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
 931         if (bm_ext) {
 932                 if (test_bit(BME_LOCKED, &bm_ext->flags))
 933                         goto proceed;
 934                 if (!test_and_set_bit(BME_NO_WRITES, &bm_ext->flags)) {
 935                         mdev->resync_locked++;
 936                 } else {
 937                         /* we did set the BME_NO_WRITES,
 938                          * but then could not set BME_LOCKED,
 939                          * so we tried again.
 940                          * drop the extra reference. */
 941                         bm_ext->lce.refcnt--;
 942                         D_ASSERT(bm_ext->lce.refcnt > 0);
 943                 }
 944                 goto check_al;
 945         } else {
 946                 /* do we rather want to try later? */
 947                 if (mdev->resync_locked > mdev->resync->nr_elements-3)
 948                         goto try_again;
 949                 /* Do or do not. There is no try. -- Yoda */
 950                 e = lc_get(mdev->resync, enr);
 951                 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
 952                 if (!bm_ext) {
 953                         const unsigned long rs_flags = mdev->resync->flags;
 954                         if (rs_flags & LC_STARVING)
 955                                 dev_warn(DEV, "Have to wait for element"
 956                                      " (resync LRU too small?)\n");
 957                         BUG_ON(rs_flags & LC_LOCKED);
 958                         goto try_again;
 959                 }
 960                 if (bm_ext->lce.lc_number != enr) {
 961                         bm_ext->rs_left = drbd_bm_e_weight(mdev, enr);
 962                         bm_ext->rs_failed = 0;
 963                         lc_committed(mdev->resync);
 964                         wake_up(&mdev->al_wait);
 965                         D_ASSERT(test_bit(BME_LOCKED, &bm_ext->flags) == 0);
 966                 }
 967                 set_bit(BME_NO_WRITES, &bm_ext->flags);
 968                 D_ASSERT(bm_ext->lce.refcnt == 1);
 969                 mdev->resync_locked++;
 970                 goto check_al;
 971         }
 972 check_al:
 973         for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
 974                 if (lc_is_used(mdev->act_log, al_enr+i))
 975                         goto try_again;
 976         }
 977         set_bit(BME_LOCKED, &bm_ext->flags);
 978 proceed:
 979         mdev->resync_wenr = LC_FREE;
 980         spin_unlock_irq(&mdev->al_lock);
 981         return 0;
 982
 983 try_again:
 984         if (bm_ext)
 985                 mdev->resync_wenr = enr;
 986         spin_unlock_irq(&mdev->al_lock);
 987         return -EAGAIN;
 988 }
 989
 990 void drbd_rs_complete_io(struct drbd_conf *mdev, sector_t sector)
 991 {
 992         unsigned int enr = BM_SECT_TO_EXT(sector);
 993         struct lc_element *e;
 994         struct bm_extent *bm_ext;
 995         unsigned long flags;
 996
 997         spin_lock_irqsave(&mdev->al_lock, flags);
 998         e = lc_find(mdev->resync, enr);
 999         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1000         if (!bm_ext) {
1001                 spin_unlock_irqrestore(&mdev->al_lock, flags);
1002                 if (__ratelimit(&drbd_ratelimit_state))
1003                         dev_err(DEV, "drbd_rs_complete_io() called, but extent not found\n");
1004                 return;
1005         }
1006
1007         if (bm_ext->lce.refcnt == 0) {
1008                 spin_unlock_irqrestore(&mdev->al_lock, flags);
1009                 dev_err(DEV, "drbd_rs_complete_io(,%llu [=%u]) called, "
1010                     "but refcnt is 0!?\n",
1011                     (unsigned long long)sector, enr);
1012                 return;
1013         }
1014
1015         if (lc_put(mdev->resync, &bm_ext->lce) == 0) {
1016                 bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */
1017                 mdev->resync_locked--;
1018                 wake_up(&mdev->al_wait);
1019         }
1020
1021         spin_unlock_irqrestore(&mdev->al_lock, flags);
1022 }
1023
1024 /**
1025  * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
1026  * @mdev:       DRBD device.
1027  */
1028 void drbd_rs_cancel_all(struct drbd_conf *mdev)
1029 {
1030         spin_lock_irq(&mdev->al_lock);
1031
1032         if (get_ldev_if_state(mdev, D_FAILED)) { /* Makes sure ->resync is there. */
1033                 lc_reset(mdev->resync);
1034                 put_ldev(mdev);
1035         }
1036         mdev->resync_locked = 0;
1037         mdev->resync_wenr = LC_FREE;
1038         spin_unlock_irq(&mdev->al_lock);
1039         wake_up(&mdev->al_wait);
1040 }
1041
1042 /**
1043  * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
1044  * @mdev:       DRBD device.
1045  *
1046  * Returns 0 upon success, -EAGAIN if at least one reference count was
1047  * not zero.
1048  */
1049 int drbd_rs_del_all(struct drbd_conf *mdev)
1050 {
1051         struct lc_element *e;
1052         struct bm_extent *bm_ext;
1053         int i;
1054
1055         spin_lock_irq(&mdev->al_lock);
1056
1057         if (get_ldev_if_state(mdev, D_FAILED)) {
1058                 /* ok, ->resync is there. */
1059                 for (i = 0; i < mdev->resync->nr_elements; i++) {
1060                         e = lc_element_by_index(mdev->resync, i);
1061                         bm_ext = lc_entry(e, struct bm_extent, lce);
1062                         if (bm_ext->lce.lc_number == LC_FREE)
1063                                 continue;
1064                         if (bm_ext->lce.lc_number == mdev->resync_wenr) {
1065                                 dev_info(DEV, "dropping %u in drbd_rs_del_all, apparently"
1066                                      " got 'synced' by application io\n",
1067                                      mdev->resync_wenr);
1068                                 D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
1069                                 D_ASSERT(test_bit(BME_NO_WRITES, &bm_ext->flags));
1070                                 clear_bit(BME_NO_WRITES, &bm_ext->flags);
1071                                 mdev->resync_wenr = LC_FREE;
1072                                 lc_put(mdev->resync, &bm_ext->lce);
1073                         }
1074                         if (bm_ext->lce.refcnt != 0) {
1075                                 dev_info(DEV, "Retrying drbd_rs_del_all() later. "
1076                                      "refcnt=%d\n", bm_ext->lce.refcnt);
1077                                 put_ldev(mdev);
1078                                 spin_unlock_irq(&mdev->al_lock);
1079                                 return -EAGAIN;
1080                         }
1081                         D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
1082                         D_ASSERT(!test_bit(BME_NO_WRITES, &bm_ext->flags));
1083                         lc_del(mdev->resync, &bm_ext->lce);
1084                 }
1085                 D_ASSERT(mdev->resync->used == 0);
1086                 put_ldev(mdev);
1087         }
1088         spin_unlock_irq(&mdev->al_lock);
1089
1090         return 0;
1091 }
1092
1093 /**
1094  * drbd_rs_failed_io() - Record information on a failure to resync the specified blocks
1095  * @mdev:       DRBD device.
1096  * @sector:     The sector number.
1097  * @size:       Size of failed IO operation, in byte.
1098  */
1099 void drbd_rs_failed_io(struct drbd_conf *mdev, sector_t sector, int size)
1100 {
1101         /* Is called from worker and receiver context _only_ */
1102         unsigned long sbnr, ebnr, lbnr;
1103         unsigned long count;
1104         sector_t esector, nr_sectors;
1105         int wake_up = 0;
1106
1107         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
1108                 dev_err(DEV, "drbd_rs_failed_io: sector=%llus size=%d nonsense!\n",
1109                                 (unsigned long long)sector, size);
1110                 return;
1111         }
1112         nr_sectors = drbd_get_capacity(mdev->this_bdev);
1113         esector = sector + (size >> 9) - 1;
1114
1115         if (!expect(sector < nr_sectors))
1116                 return;
1117         if (!expect(esector < nr_sectors))
1118                 esector = nr_sectors - 1;
1119
1120         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
1121
1122         /*
1123          * round up start sector, round down end sector.  we make sure we only
1124          * handle full, aligned, BM_BLOCK_SIZE (4K) blocks */
1125         if (unlikely(esector < BM_SECT_PER_BIT-1))
1126                 return;
1127         if (unlikely(esector == (nr_sectors-1)))
1128                 ebnr = lbnr;
1129         else
1130                 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
1131         sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
1132
1133         if (sbnr > ebnr)
1134                 return;
1135
1136         /*
1137          * ok, (capacity & 7) != 0 sometimes, but who cares...
1138          * we count rs_{total,left} in bits, not sectors.
1139          */
1140         spin_lock_irq(&mdev->al_lock);
1141         count = drbd_bm_count_bits(mdev, sbnr, ebnr);
1142         if (count) {
1143                 mdev->rs_failed += count;
1144
1145                 if (get_ldev(mdev)) {
1146                         drbd_try_clear_on_disk_bm(mdev, sector, count, false);
1147                         put_ldev(mdev);
1148                 }
1149
1150                 /* just wake_up unconditional now, various lc_chaged(),
1151                  * lc_put() in drbd_try_clear_on_disk_bm(). */
1152                 wake_up = 1;
1153         }
1154         spin_unlock_irq(&mdev->al_lock);
1155         if (wake_up)
1156                 wake_up(&mdev->al_wait);
1157 }