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 /* all fields on disc in big endian */
  35 struct __packed al_transaction_on_disk {
  36         /* don't we all like magic */
  37         __be32  magic;
  38
  39         /* to identify the most recent transaction block
  40          * in the on disk ring buffer */
  41         __be32  tr_number;
  42
  43         /* checksum on the full 4k block, with this field set to 0. */
  44         __be32  crc32c;
  45
  46         /* type of transaction, special transaction types like:
  47          * purge-all, set-all-idle, set-all-active, ... to-be-defined */
  48         __be16  transaction_type;
  49
  50         /* we currently allow only a few thousand extents,
  51          * so 16bit will be enough for the slot number. */
  52
  53         /* how many updates in this transaction */
  54         __be16  n_updates;
  55
  56         /* maximum slot number, "al-extents" in drbd.conf speak.
  57          * Having this in each transaction should make reconfiguration
  58          * of that parameter easier. */
  59         __be16  context_size;
  60
  61         /* slot number the context starts with */
  62         __be16  context_start_slot_nr;
  63
  64         /* Some reserved bytes.  Expected usage is a 64bit counter of
  65          * sectors-written since device creation, and other data generation tag
  66          * supporting usage */
  67         __be32  __reserved[4];
  68
  69         /* --- 36 byte used --- */
  70
  71         /* Reserve space for up to AL_UPDATES_PER_TRANSACTION changes
  72          * in one transaction, then use the remaining byte in the 4k block for
  73          * context information.  "Flexible" number of updates per transaction
  74          * does not help, as we have to account for the case when all update
  75          * slots are used anyways, so it would only complicate code without
  76          * additional benefit.
  77          */
  78         __be16  update_slot_nr[AL_UPDATES_PER_TRANSACTION];
  79
  80         /* but the extent number is 32bit, which at an extent size of 4 MiB
  81          * allows to cover device sizes of up to 2**54 Byte (16 PiB) */
  82         __be32  update_extent_nr[AL_UPDATES_PER_TRANSACTION];
  83
  84         /* --- 420 bytes used (36 + 64*6) --- */
  85
  86         /* 4096 - 420 = 3676 = 919 * 4 */
  87         __be32  context[AL_CONTEXT_PER_TRANSACTION];
  88 };
  89
  90 struct update_odbm_work {
  91         struct drbd_work w;
  92         unsigned int enr;
  93 };
  94
  95 struct update_al_work {
  96         struct drbd_work w;
  97         struct completion event;
  98         int err;
  99 };
 100
 101 struct drbd_atodb_wait {
 102         atomic_t           count;
 103         struct completion  io_done;
 104         struct drbd_conf   *mdev;
 105         int                error;
 106 };
 107
 108
 109 static int w_al_write_transaction(struct drbd_work *, int);
 110
 111 static int _drbd_md_sync_page_io(struct drbd_conf *mdev,
 112                                  struct drbd_backing_dev *bdev,
 113                                  struct page *page, sector_t sector,
 114                                  int rw, int size)
 115 {
 116         struct bio *bio;
 117         struct drbd_md_io md_io;
 118         int ok;
 119
 120         md_io.mdev = mdev;
 121         init_completion(&md_io.event);
 122         md_io.error = 0;
 123
 124         if ((rw & WRITE) && !test_bit(MD_NO_FUA, &mdev->flags))
 125                 rw |= REQ_FUA | REQ_FLUSH;
 126         rw |= REQ_SYNC;
 127
 128         bio = bio_alloc_drbd(GFP_NOIO);
 129         bio->bi_bdev = bdev->md_bdev;
 130         bio->bi_sector = sector;
 131         ok = (bio_add_page(bio, page, size, 0) == size);
 132         if (!ok)
 133                 goto out;
 134         bio->bi_private = &md_io;
 135         bio->bi_end_io = drbd_md_io_complete;
 136         bio->bi_rw = rw;
 137
 138         if (drbd_insert_fault(mdev, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
 139                 bio_endio(bio, -EIO);
 140         else
 141                 submit_bio(rw, bio);
 142         wait_for_completion(&md_io.event);
 143         ok = bio_flagged(bio, BIO_UPTODATE) && md_io.error == 0;
 144
 145  out:
 146         bio_put(bio);
 147         return ok;
 148 }
 149
 150 int drbd_md_sync_page_io(struct drbd_conf *mdev, struct drbd_backing_dev *bdev,
 151                          sector_t sector, int rw)
 152 {
 153         int ok;
 154         struct page *iop = mdev->md_io_page;
 155
 156         D_ASSERT(mutex_is_locked(&mdev->md_io_mutex));
 157
 158         BUG_ON(!bdev->md_bdev);
 159
 160         dev_dbg(DEV, "meta_data io: %s [%d]:%s(,%llus,%s)\n",
 161              current->comm, current->pid, __func__,
 162              (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
 163
 164         if (sector < drbd_md_first_sector(bdev) ||
 165             sector + 7 > drbd_md_last_sector(bdev))
 166                 dev_alert(DEV, "%s [%d]:%s(,%llus,%s) out of range md access!\n",
 167                      current->comm, current->pid, __func__,
 168                      (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
 169
 170         ok = _drbd_md_sync_page_io(mdev, bdev, iop, sector, rw, MD_BLOCK_SIZE);
 171         if (unlikely(!ok)) {
 172                 dev_err(DEV, "drbd_md_sync_page_io(,%llus,%s) failed!\n",
 173                     (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
 174                 return 0;
 175         }
 176
 177         return ok;
 178 }
 179
 180 static struct lc_element *_al_get(struct drbd_conf *mdev, unsigned int enr)
 181 {
 182         struct lc_element *al_ext;
 183         struct lc_element *tmp;
 184         int wake;
 185
 186         spin_lock_irq(&mdev->al_lock);
 187         tmp = lc_find(mdev->resync, enr/AL_EXT_PER_BM_SECT);
 188         if (unlikely(tmp != NULL)) {
 189                 struct bm_extent  *bm_ext = lc_entry(tmp, struct bm_extent, lce);
 190                 if (test_bit(BME_NO_WRITES, &bm_ext->flags)) {
 191                         wake = !test_and_set_bit(BME_PRIORITY, &bm_ext->flags);
 192                         spin_unlock_irq(&mdev->al_lock);
 193                         if (wake)
 194                                 wake_up(&mdev->al_wait);
 195                         return NULL;
 196                 }
 197         }
 198         al_ext = lc_get(mdev->act_log, enr);
 199         spin_unlock_irq(&mdev->al_lock);
 200         return al_ext;
 201 }
 202
 203 void drbd_al_begin_io(struct drbd_conf *mdev, sector_t sector)
 204 {
 205         unsigned int enr = (sector >> (AL_EXTENT_SHIFT-9));
 206         struct lc_element *al_ext;
 207         struct update_al_work al_work;
 208
 209         D_ASSERT(atomic_read(&mdev->local_cnt) > 0);
 210
 211         wait_event(mdev->al_wait, (al_ext = _al_get(mdev, enr)));
 212
 213         if (al_ext->lc_number != enr) {
 214                 /* drbd_al_write_transaction(mdev,al_ext,enr);
 215                  * recurses into generic_make_request(), which
 216                  * disallows recursion, bios being serialized on the
 217                  * current->bio_tail list now.
 218                  * we have to delegate updates to the activity log
 219                  * to the worker thread. */
 220
 221                 /* Serialize multiple transactions.
 222                  * This uses test_and_set_bit, memory barrier is implicit.
 223                  * Optimization potential:
 224                  * first check for transaction number > old transaction number,
 225                  * so not all waiters have to lock/unlock.  */
 226                 wait_event(mdev->al_wait, lc_try_lock_for_transaction(mdev->act_log));
 227
 228                 /* Double check: it may have been committed by someone else,
 229                  * while we have been waiting for the lock. */
 230                 if (al_ext->lc_number != enr) {
 231                         init_completion(&al_work.event);
 232                         al_work.w.cb = w_al_write_transaction;
 233                         al_work.w.mdev = mdev;
 234                         drbd_queue_work_front(&mdev->tconn->data.work, &al_work.w);
 235                         wait_for_completion(&al_work.event);
 236
 237                         mdev->al_writ_cnt++;
 238
 239                         spin_lock_irq(&mdev->al_lock);
 240                         /* FIXME
 241                         if (al_work.err)
 242                                 we need an "lc_cancel" here;
 243                         */
 244                         lc_committed(mdev->act_log);
 245                         spin_unlock_irq(&mdev->al_lock);
 246                 }
 247                 lc_unlock(mdev->act_log);
 248                 wake_up(&mdev->al_wait);
 249         }
 250 }
 251
 252 void drbd_al_complete_io(struct drbd_conf *mdev, sector_t sector)
 253 {
 254         unsigned int enr = (sector >> (AL_EXTENT_SHIFT-9));
 255         struct lc_element *extent;
 256         unsigned long flags;
 257
 258         spin_lock_irqsave(&mdev->al_lock, flags);
 259
 260         extent = lc_find(mdev->act_log, enr);
 261
 262         if (!extent) {
 263                 spin_unlock_irqrestore(&mdev->al_lock, flags);
 264                 dev_err(DEV, "al_complete_io() called on inactive extent %u\n", enr);
 265                 return;
 266         }
 267
 268         if (lc_put(mdev->act_log, extent) == 0)
 269                 wake_up(&mdev->al_wait);
 270
 271         spin_unlock_irqrestore(&mdev->al_lock, flags);
 272 }
 273
 274 #if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
 275 /* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
 276  * are still coupled, or assume too much about their relation.
 277  * Code below will not work if this is violated.
 278  * Will be cleaned up with some followup patch.
 279  */
 280 # error FIXME
 281 #endif
 282
 283 static unsigned int al_extent_to_bm_page(unsigned int al_enr)
 284 {
 285         return al_enr >>
 286                 /* bit to page */
 287                 ((PAGE_SHIFT + 3) -
 288                 /* al extent number to bit */
 289                  (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
 290 }
 291
 292 static unsigned int rs_extent_to_bm_page(unsigned int rs_enr)
 293 {
 294         return rs_enr >>
 295                 /* bit to page */
 296                 ((PAGE_SHIFT + 3) -
 297                 /* al extent number to bit */
 298                  (BM_EXT_SHIFT - BM_BLOCK_SHIFT));
 299 }
 300
 301 static int
 302 w_al_write_transaction(struct drbd_work *w, int unused)
 303 {
 304         struct update_al_work *aw = container_of(w, struct update_al_work, w);
 305         struct drbd_conf *mdev = w->mdev;
 306         struct al_transaction_on_disk *buffer;
 307         struct lc_element *e;
 308         sector_t sector;
 309         int i, mx;
 310         unsigned extent_nr;
 311         unsigned crc = 0;
 312
 313         if (!get_ldev(mdev)) {
 314                 dev_err(DEV, "disk is %s, cannot start al transaction\n",
 315                         drbd_disk_str(mdev->state.disk));
 316                 aw->err = -EIO;
 317                 complete(&((struct update_al_work *)w)->event);
 318                 return 0;
 319         }
 320
 321         /* The bitmap write may have failed, causing a state change. */
 322         if (mdev->state.disk < D_INCONSISTENT) {
 323                 dev_err(DEV,
 324                         "disk is %s, cannot write al transaction\n",
 325                         drbd_disk_str(mdev->state.disk));
 326                 aw->err = -EIO;
 327                 complete(&((struct update_al_work *)w)->event);
 328                 put_ldev(mdev);
 329                 return 0;
 330         }
 331
 332         mutex_lock(&mdev->md_io_mutex); /* protects md_io_buffer, al_tr_cycle, ... */
 333         buffer = page_address(mdev->md_io_page);
 334
 335         memset(buffer, 0, sizeof(*buffer));
 336         buffer->magic = cpu_to_be32(DRBD_AL_MAGIC);
 337         buffer->tr_number = cpu_to_be32(mdev->al_tr_number);
 338
 339         i = 0;
 340
 341         /* Even though no one can start to change this list
 342          * once we set the LC_LOCKED -- from drbd_al_begin_io(),
 343          * lc_try_lock_for_transaction() --, someone may still
 344          * be in the process of changing it. */
 345         spin_lock_irq(&mdev->al_lock);
 346         list_for_each_entry(e, &mdev->act_log->to_be_changed, list) {
 347                 if (i == AL_UPDATES_PER_TRANSACTION) {
 348                         i++;
 349                         break;
 350                 }
 351                 buffer->update_slot_nr[i] = cpu_to_be16(e->lc_index);
 352                 buffer->update_extent_nr[i] = cpu_to_be32(e->lc_new_number);
 353                 if (e->lc_number != LC_FREE)
 354                         drbd_bm_mark_for_writeout(mdev,
 355                                         al_extent_to_bm_page(e->lc_number));
 356                 i++;
 357         }
 358         spin_unlock_irq(&mdev->al_lock);
 359         BUG_ON(i > AL_UPDATES_PER_TRANSACTION);
 360
 361         buffer->n_updates = cpu_to_be16(i);
 362         for ( ; i < AL_UPDATES_PER_TRANSACTION; i++) {
 363                 buffer->update_slot_nr[i] = cpu_to_be16(-1);
 364                 buffer->update_extent_nr[i] = cpu_to_be32(LC_FREE);
 365         }
 366
 367         buffer->context_size = cpu_to_be16(mdev->act_log->nr_elements);
 368         buffer->context_start_slot_nr = cpu_to_be16(mdev->al_tr_cycle);
 369
 370         mx = min_t(int, AL_CONTEXT_PER_TRANSACTION,
 371                    mdev->act_log->nr_elements - mdev->al_tr_cycle);
 372         for (i = 0; i < mx; i++) {
 373                 unsigned idx = mdev->al_tr_cycle + i;
 374                 extent_nr = lc_element_by_index(mdev->act_log, idx)->lc_number;
 375                 buffer->context[i] = cpu_to_be32(extent_nr);
 376         }
 377         for (; i < AL_CONTEXT_PER_TRANSACTION; i++)
 378                 buffer->context[i] = cpu_to_be32(LC_FREE);
 379
 380         mdev->al_tr_cycle += AL_CONTEXT_PER_TRANSACTION;
 381         if (mdev->al_tr_cycle >= mdev->act_log->nr_elements)
 382                 mdev->al_tr_cycle = 0;
 383
 384         sector =  mdev->ldev->md.md_offset
 385                 + mdev->ldev->md.al_offset
 386                 + mdev->al_tr_pos * (MD_BLOCK_SIZE>>9);
 387
 388         crc = crc32c(0, buffer, 4096);
 389         buffer->crc32c = cpu_to_be32(crc);
 390
 391         if (drbd_bm_write_hinted(mdev))
 392                 aw->err = -EIO;
 393                 /* drbd_chk_io_error done already */
 394         else if (!drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)) {
 395                 aw->err = -EIO;
 396                 drbd_chk_io_error(mdev, 1, true);
 397         } else {
 398                 /* advance ringbuffer position and transaction counter */
 399                 mdev->al_tr_pos = (mdev->al_tr_pos + 1) % (MD_AL_SECTORS*512/MD_BLOCK_SIZE);
 400                 mdev->al_tr_number++;
 401         }
 402
 403         mutex_unlock(&mdev->md_io_mutex);
 404         complete(&((struct update_al_work *)w)->event);
 405         put_ldev(mdev);
 406
 407         return 0;
 408 }
 409
 410 /* FIXME
 411  * reading of the activity log,
 412  * and potentially dirtying of the affected bitmap regions,
 413  * should be done from userland only.
 414  * DRBD would simply always attach with an empty activity log,
 415  * and refuse to attach to something that looks like a crashed primary.
 416  */
 417
 418 /**
 419  * drbd_al_read_tr() - Read a single transaction from the on disk activity log
 420  * @mdev:       DRBD device.
 421  * @bdev:       Block device to read form.
 422  * @b:          pointer to an al_transaction.
 423  * @index:      On disk slot of the transaction to read.
 424  *
 425  * Returns -1 on IO error, 0 on checksum error and 1 upon success.
 426  */
 427 static int drbd_al_read_tr(struct drbd_conf *mdev,
 428                            struct drbd_backing_dev *bdev,
 429                            int index)
 430 {
 431         struct al_transaction_on_disk *b = page_address(mdev->md_io_page);
 432         sector_t sector;
 433         u32 crc;
 434
 435         sector =  bdev->md.md_offset
 436                 + bdev->md.al_offset
 437                 + index * (MD_BLOCK_SIZE>>9);
 438
 439         /* Dont process error normally,
 440          * as this is done before disk is attached! */
 441         if (!drbd_md_sync_page_io(mdev, bdev, sector, READ))
 442                 return -1;
 443
 444         if (!expect(b->magic == cpu_to_be32(DRBD_AL_MAGIC)))
 445                 return 0;
 446
 447         if (!expect(be16_to_cpu(b->n_updates) <= AL_UPDATES_PER_TRANSACTION))
 448                 return 0;
 449
 450         if (!expect(be16_to_cpu(b->context_size) <= DRBD_AL_EXTENTS_MAX))
 451                 return 0;
 452
 453         if (!expect(be16_to_cpu(b->context_start_slot_nr) < DRBD_AL_EXTENTS_MAX))
 454                 return 0;
 455
 456         crc = be32_to_cpu(b->crc32c);
 457         b->crc32c = 0;
 458         if (!expect(crc == crc32c(0, b, 4096)))
 459                 return 0;
 460
 461         return 1;
 462 }
 463
 464 /**
 465  * drbd_al_read_log() - Restores the activity log from its on disk representation.
 466  * @mdev:       DRBD device.
 467  * @bdev:       Block device to read form.
 468  *
 469  * Returns 1 on success, returns 0 when reading the log failed due to IO errors.
 470  */
 471 int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
 472 {
 473         struct al_transaction_on_disk *b;
 474         int i;
 475         int rv;
 476         int mx;
 477         int active_extents = 0;
 478         int transactions = 0;
 479         int found_valid = 0;
 480         int from = 0;
 481         int to = 0;
 482         u32 from_tnr = 0;
 483         u32 to_tnr = 0;
 484         u32 cnr;
 485
 486         /* Note that this is expected to be called with a newly created,
 487          * clean and all unused activity log of the "expected size".
 488          */
 489
 490         /* lock out all other meta data io for now,
 491          * and make sure the page is mapped.
 492          */
 493         mutex_lock(&mdev->md_io_mutex);
 494         b = page_address(mdev->md_io_page);
 495
 496         /* Always use the full ringbuffer space for now.
 497          * possible optimization: read in all of it,
 498          * then scan the in-memory pages. */
 499
 500         mx = (MD_AL_SECTORS*512/MD_BLOCK_SIZE);
 501
 502         /* Find the valid transaction in the log */
 503         for (i = 0; i < mx; i++) {
 504                 rv = drbd_al_read_tr(mdev, bdev, i);
 505                 /* invalid data in that block */
 506                 if (rv == 0)
 507                         continue;
 508
 509                 /* IO error */
 510                 if (rv == -1) {
 511                         mutex_unlock(&mdev->md_io_mutex);
 512                         return 0;
 513                 }
 514
 515                 cnr = be32_to_cpu(b->tr_number);
 516                 if (++found_valid == 1) {
 517                         from = i;
 518                         to = i;
 519                         from_tnr = cnr;
 520                         to_tnr = cnr;
 521                         continue;
 522                 }
 523
 524                 D_ASSERT(cnr != to_tnr);
 525                 D_ASSERT(cnr != from_tnr);
 526                 if ((int)cnr - (int)from_tnr < 0) {
 527                         D_ASSERT(from_tnr - cnr + i - from == mx);
 528                         from = i;
 529                         from_tnr = cnr;
 530                 }
 531                 if ((int)cnr - (int)to_tnr > 0) {
 532                         D_ASSERT(cnr - to_tnr == i - to);
 533                         to = i;
 534                         to_tnr = cnr;
 535                 }
 536         }
 537
 538         if (!found_valid) {
 539                 dev_warn(DEV, "No usable activity log found.\n");
 540                 mutex_unlock(&mdev->md_io_mutex);
 541                 return 1;
 542         }
 543
 544         /* Read the valid transactions.
 545          * dev_info(DEV, "Reading from %d to %d.\n",from,to); */
 546         i = from;
 547         while (1) {
 548                 struct lc_element *e;
 549                 unsigned j, n, slot, extent_nr;
 550
 551                 rv = drbd_al_read_tr(mdev, bdev, i);
 552                 if (!expect(rv != 0))
 553                         goto cancel;
 554                 if (rv == -1) {
 555                         mutex_unlock(&mdev->md_io_mutex);
 556                         return 0;
 557                 }
 558
 559                 /* deal with different transaction types.
 560                  * not yet implemented */
 561                 if (!expect(b->transaction_type == 0))
 562                         goto cancel;
 563
 564                 /* on the fly re-create/resize activity log?
 565                  * will be a special transaction type flag. */
 566                 if (!expect(be16_to_cpu(b->context_size) == mdev->act_log->nr_elements))
 567                         goto cancel;
 568                 if (!expect(be16_to_cpu(b->context_start_slot_nr) < mdev->act_log->nr_elements))
 569                         goto cancel;
 570
 571                 /* We are the only user of the activity log right now,
 572                  * don't actually need to take that lock. */
 573                 spin_lock_irq(&mdev->al_lock);
 574
 575                 /* first, apply the context, ... */
 576                 for (j = 0, slot = be16_to_cpu(b->context_start_slot_nr);
 577                      j < AL_CONTEXT_PER_TRANSACTION &&
 578                      slot < mdev->act_log->nr_elements; j++, slot++) {
 579                         extent_nr = be32_to_cpu(b->context[j]);
 580                         e = lc_element_by_index(mdev->act_log, slot);
 581                         if (e->lc_number != extent_nr) {
 582                                 if (extent_nr != LC_FREE)
 583                                         active_extents++;
 584                                 else
 585                                         active_extents--;
 586                         }
 587                         lc_set(mdev->act_log, extent_nr, slot);
 588                 }
 589
 590                 /* ... then apply the updates,
 591                  * which override the context information.
 592                  * drbd_al_read_tr already did the rangecheck
 593                  * on n <= AL_UPDATES_PER_TRANSACTION */
 594                 n = be16_to_cpu(b->n_updates);
 595                 for (j = 0; j < n; j++) {
 596                         slot = be16_to_cpu(b->update_slot_nr[j]);
 597                         extent_nr = be32_to_cpu(b->update_extent_nr[j]);
 598                         if (!expect(slot < mdev->act_log->nr_elements))
 599                                 break;
 600                         e = lc_element_by_index(mdev->act_log, slot);
 601                         if (e->lc_number != extent_nr) {
 602                                 if (extent_nr != LC_FREE)
 603                                         active_extents++;
 604                                 else
 605                                         active_extents--;
 606                         }
 607                         lc_set(mdev->act_log, extent_nr, slot);
 608                 }
 609                 spin_unlock_irq(&mdev->al_lock);
 610
 611                 transactions++;
 612
 613 cancel:
 614                 if (i == to)
 615                         break;
 616                 i++;
 617                 if (i >= mx)
 618                         i = 0;
 619         }
 620
 621         mdev->al_tr_number = to_tnr+1;
 622         mdev->al_tr_pos = (to + 1) % (MD_AL_SECTORS*512/MD_BLOCK_SIZE);
 623
 624         /* ok, we are done with it */
 625         mutex_unlock(&mdev->md_io_mutex);
 626
 627         dev_info(DEV, "Found %d transactions (%d active extents) in activity log.\n",
 628              transactions, active_extents);
 629
 630         return 1;
 631 }
 632
 633 /**
 634  * drbd_al_apply_to_bm() - Sets the bitmap to dirty(1) where covered by active AL extents
 635  * @mdev:       DRBD device.
 636  */
 637 void drbd_al_apply_to_bm(struct drbd_conf *mdev)
 638 {
 639         unsigned int enr;
 640         unsigned long add = 0;
 641         char ppb[10];
 642         int i, tmp;
 643
 644         wait_event(mdev->al_wait, lc_try_lock(mdev->act_log));
 645
 646         for (i = 0; i < mdev->act_log->nr_elements; i++) {
 647                 enr = lc_element_by_index(mdev->act_log, i)->lc_number;
 648                 if (enr == LC_FREE)
 649                         continue;
 650                 tmp = drbd_bm_ALe_set_all(mdev, enr);
 651                 dynamic_dev_dbg(DEV, "AL: set %d bits in extent %u\n", tmp, enr);
 652                 add += tmp;
 653         }
 654
 655         lc_unlock(mdev->act_log);
 656         wake_up(&mdev->al_wait);
 657
 658         dev_info(DEV, "Marked additional %s as out-of-sync based on AL.\n",
 659              ppsize(ppb, Bit2KB(add)));
 660 }
 661
 662 static int _try_lc_del(struct drbd_conf *mdev, struct lc_element *al_ext)
 663 {
 664         int rv;
 665
 666         spin_lock_irq(&mdev->al_lock);
 667         rv = (al_ext->refcnt == 0);
 668         if (likely(rv))
 669                 lc_del(mdev->act_log, al_ext);
 670         spin_unlock_irq(&mdev->al_lock);
 671
 672         return rv;
 673 }
 674
 675 /**
 676  * drbd_al_shrink() - Removes all active extents form the activity log
 677  * @mdev:       DRBD device.
 678  *
 679  * Removes all active extents form the activity log, waiting until
 680  * the reference count of each entry dropped to 0 first, of course.
 681  *
 682  * You need to lock mdev->act_log with lc_try_lock() / lc_unlock()
 683  */
 684 void drbd_al_shrink(struct drbd_conf *mdev)
 685 {
 686         struct lc_element *al_ext;
 687         int i;
 688
 689         D_ASSERT(test_bit(__LC_LOCKED, &mdev->act_log->flags));
 690
 691         for (i = 0; i < mdev->act_log->nr_elements; i++) {
 692                 al_ext = lc_element_by_index(mdev->act_log, i);
 693                 if (al_ext->lc_number == LC_FREE)
 694                         continue;
 695                 wait_event(mdev->al_wait, _try_lc_del(mdev, al_ext));
 696         }
 697
 698         wake_up(&mdev->al_wait);
 699 }
 700
 701 static int w_update_odbm(struct drbd_work *w, int unused)
 702 {
 703         struct update_odbm_work *udw = container_of(w, struct update_odbm_work, w);
 704         struct drbd_conf *mdev = w->mdev;
 705         struct sib_info sib = { .sib_reason = SIB_SYNC_PROGRESS, };
 706
 707         if (!get_ldev(mdev)) {
 708                 if (__ratelimit(&drbd_ratelimit_state))
 709                         dev_warn(DEV, "Can not update on disk bitmap, local IO disabled.\n");
 710                 kfree(udw);
 711                 return 0;
 712         }
 713
 714         drbd_bm_write_page(mdev, rs_extent_to_bm_page(udw->enr));
 715         put_ldev(mdev);
 716
 717         kfree(udw);
 718
 719         if (drbd_bm_total_weight(mdev) <= mdev->rs_failed) {
 720                 switch (mdev->state.conn) {
 721                 case C_SYNC_SOURCE:  case C_SYNC_TARGET:
 722                 case C_PAUSED_SYNC_S: case C_PAUSED_SYNC_T:
 723                         drbd_resync_finished(mdev);
 724                 default:
 725                         /* nothing to do */
 726                         break;
 727                 }
 728         }
 729         drbd_bcast_event(mdev, &sib);
 730
 731         return 0;
 732 }
 733
 734
 735 /* ATTENTION. The AL's extents are 4MB each, while the extents in the
 736  * resync LRU-cache are 16MB each.
 737  * The caller of this function has to hold an get_ldev() reference.
 738  *
 739  * TODO will be obsoleted once we have a caching lru of the on disk bitmap
 740  */
 741 static void drbd_try_clear_on_disk_bm(struct drbd_conf *mdev, sector_t sector,
 742                                       int count, int success)
 743 {
 744         struct lc_element *e;
 745         struct update_odbm_work *udw;
 746
 747         unsigned int enr;
 748
 749         D_ASSERT(atomic_read(&mdev->local_cnt));
 750
 751         /* I simply assume that a sector/size pair never crosses
 752          * a 16 MB extent border. (Currently this is true...) */
 753         enr = BM_SECT_TO_EXT(sector);
 754
 755         e = lc_get(mdev->resync, enr);
 756         if (e) {
 757                 struct bm_extent *ext = lc_entry(e, struct bm_extent, lce);
 758                 if (ext->lce.lc_number == enr) {
 759                         if (success)
 760                                 ext->rs_left -= count;
 761                         else
 762                                 ext->rs_failed += count;
 763                         if (ext->rs_left < ext->rs_failed) {
 764                                 dev_err(DEV, "BAD! sector=%llus enr=%u rs_left=%d "
 765                                     "rs_failed=%d count=%d\n",
 766                                      (unsigned long long)sector,
 767                                      ext->lce.lc_number, ext->rs_left,
 768                                      ext->rs_failed, count);
 769                                 dump_stack();
 770
 771                                 lc_put(mdev->resync, &ext->lce);
 772                                 conn_request_state(mdev->tconn, NS(conn, C_DISCONNECTING), CS_HARD);
 773                                 return;
 774                         }
 775                 } else {
 776                         /* Normally this element should be in the cache,
 777                          * since drbd_rs_begin_io() pulled it already in.
 778                          *
 779                          * But maybe an application write finished, and we set
 780                          * something outside the resync lru_cache in sync.
 781                          */
 782                         int rs_left = drbd_bm_e_weight(mdev, enr);
 783                         if (ext->flags != 0) {
 784                                 dev_warn(DEV, "changing resync lce: %d[%u;%02lx]"
 785                                      " -> %d[%u;00]\n",
 786                                      ext->lce.lc_number, ext->rs_left,
 787                                      ext->flags, enr, rs_left);
 788                                 ext->flags = 0;
 789                         }
 790                         if (ext->rs_failed) {
 791                                 dev_warn(DEV, "Kicking resync_lru element enr=%u "
 792                                      "out with rs_failed=%d\n",
 793                                      ext->lce.lc_number, ext->rs_failed);
 794                         }
 795                         ext->rs_left = rs_left;
 796                         ext->rs_failed = success ? 0 : count;
 797                         /* we don't keep a persistent log of the resync lru,
 798                          * we can commit any change right away. */
 799                         lc_committed(mdev->resync);
 800                 }
 801                 lc_put(mdev->resync, &ext->lce);
 802                 /* no race, we are within the al_lock! */
 803
 804                 if (ext->rs_left == ext->rs_failed) {
 805                         ext->rs_failed = 0;
 806
 807                         udw = kmalloc(sizeof(*udw), GFP_ATOMIC);
 808                         if (udw) {
 809                                 udw->enr = ext->lce.lc_number;
 810                                 udw->w.cb = w_update_odbm;
 811                                 udw->w.mdev = mdev;
 812                                 drbd_queue_work_front(&mdev->tconn->data.work, &udw->w);
 813                         } else {
 814                                 dev_warn(DEV, "Could not kmalloc an udw\n");
 815                         }
 816                 }
 817         } else {
 818                 dev_err(DEV, "lc_get() failed! locked=%d/%d flags=%lu\n",
 819                     mdev->resync_locked,
 820                     mdev->resync->nr_elements,
 821                     mdev->resync->flags);
 822         }
 823 }
 824
 825 void drbd_advance_rs_marks(struct drbd_conf *mdev, unsigned long still_to_go)
 826 {
 827         unsigned long now = jiffies;
 828         unsigned long last = mdev->rs_mark_time[mdev->rs_last_mark];
 829         int next = (mdev->rs_last_mark + 1) % DRBD_SYNC_MARKS;
 830         if (time_after_eq(now, last + DRBD_SYNC_MARK_STEP)) {
 831                 if (mdev->rs_mark_left[mdev->rs_last_mark] != still_to_go &&
 832                     mdev->state.conn != C_PAUSED_SYNC_T &&
 833                     mdev->state.conn != C_PAUSED_SYNC_S) {
 834                         mdev->rs_mark_time[next] = now;
 835                         mdev->rs_mark_left[next] = still_to_go;
 836                         mdev->rs_last_mark = next;
 837                 }
 838         }
 839 }
 840
 841 /* clear the bit corresponding to the piece of storage in question:
 842  * size byte of data starting from sector.  Only clear a bits of the affected
 843  * one ore more _aligned_ BM_BLOCK_SIZE blocks.
 844  *
 845  * called by worker on C_SYNC_TARGET and receiver on SyncSource.
 846  *
 847  */
 848 void __drbd_set_in_sync(struct drbd_conf *mdev, sector_t sector, int size,
 849                        const char *file, const unsigned int line)
 850 {
 851         /* Is called from worker and receiver context _only_ */
 852         unsigned long sbnr, ebnr, lbnr;
 853         unsigned long count = 0;
 854         sector_t esector, nr_sectors;
 855         int wake_up = 0;
 856         unsigned long flags;
 857
 858         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
 859                 dev_err(DEV, "drbd_set_in_sync: sector=%llus size=%d nonsense!\n",
 860                                 (unsigned long long)sector, size);
 861                 return;
 862         }
 863         nr_sectors = drbd_get_capacity(mdev->this_bdev);
 864         esector = sector + (size >> 9) - 1;
 865
 866         if (!expect(sector < nr_sectors))
 867                 return;
 868         if (!expect(esector < nr_sectors))
 869                 esector = nr_sectors - 1;
 870
 871         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
 872
 873         /* we clear it (in sync).
 874          * round up start sector, round down end sector.  we make sure we only
 875          * clear full, aligned, BM_BLOCK_SIZE (4K) blocks */
 876         if (unlikely(esector < BM_SECT_PER_BIT-1))
 877                 return;
 878         if (unlikely(esector == (nr_sectors-1)))
 879                 ebnr = lbnr;
 880         else
 881                 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
 882         sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
 883
 884         if (sbnr > ebnr)
 885                 return;
 886
 887         /*
 888          * ok, (capacity & 7) != 0 sometimes, but who cares...
 889          * we count rs_{total,left} in bits, not sectors.
 890          */
 891         count = drbd_bm_clear_bits(mdev, sbnr, ebnr);
 892         if (count && get_ldev(mdev)) {
 893                 drbd_advance_rs_marks(mdev, drbd_bm_total_weight(mdev));
 894                 spin_lock_irqsave(&mdev->al_lock, flags);
 895                 drbd_try_clear_on_disk_bm(mdev, sector, count, true);
 896                 spin_unlock_irqrestore(&mdev->al_lock, flags);
 897
 898                 /* just wake_up unconditional now, various lc_chaged(),
 899                  * lc_put() in drbd_try_clear_on_disk_bm(). */
 900                 wake_up = 1;
 901                 put_ldev(mdev);
 902         }
 903         if (wake_up)
 904                 wake_up(&mdev->al_wait);
 905 }
 906
 907 /*
 908  * this is intended to set one request worth of data out of sync.
 909  * affects at least 1 bit,
 910  * and at most 1+DRBD_MAX_BIO_SIZE/BM_BLOCK_SIZE bits.
 911  *
 912  * called by tl_clear and drbd_send_dblock (==drbd_make_request).
 913  * so this can be _any_ process.
 914  */
 915 int __drbd_set_out_of_sync(struct drbd_conf *mdev, sector_t sector, int size,
 916                             const char *file, const unsigned int line)
 917 {
 918         unsigned long sbnr, ebnr, lbnr, flags;
 919         sector_t esector, nr_sectors;
 920         unsigned int enr, count = 0;
 921         struct lc_element *e;
 922
 923         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
 924                 dev_err(DEV, "sector: %llus, size: %d\n",
 925                         (unsigned long long)sector, size);
 926                 return 0;
 927         }
 928
 929         if (!get_ldev(mdev))
 930                 return 0; /* no disk, no metadata, no bitmap to set bits in */
 931
 932         nr_sectors = drbd_get_capacity(mdev->this_bdev);
 933         esector = sector + (size >> 9) - 1;
 934
 935         if (!expect(sector < nr_sectors))
 936                 goto out;
 937         if (!expect(esector < nr_sectors))
 938                 esector = nr_sectors - 1;
 939
 940         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
 941
 942         /* we set it out of sync,
 943          * we do not need to round anything here */
 944         sbnr = BM_SECT_TO_BIT(sector);
 945         ebnr = BM_SECT_TO_BIT(esector);
 946
 947         /* ok, (capacity & 7) != 0 sometimes, but who cares...
 948          * we count rs_{total,left} in bits, not sectors.  */
 949         spin_lock_irqsave(&mdev->al_lock, flags);
 950         count = drbd_bm_set_bits(mdev, sbnr, ebnr);
 951
 952         enr = BM_SECT_TO_EXT(sector);
 953         e = lc_find(mdev->resync, enr);
 954         if (e)
 955                 lc_entry(e, struct bm_extent, lce)->rs_left += count;
 956         spin_unlock_irqrestore(&mdev->al_lock, flags);
 957
 958 out:
 959         put_ldev(mdev);
 960
 961         return count;
 962 }
 963
 964 static
 965 struct bm_extent *_bme_get(struct drbd_conf *mdev, unsigned int enr)
 966 {
 967         struct lc_element *e;
 968         struct bm_extent *bm_ext;
 969         int wakeup = 0;
 970         unsigned long rs_flags;
 971
 972         spin_lock_irq(&mdev->al_lock);
 973         if (mdev->resync_locked > mdev->resync->nr_elements/2) {
 974                 spin_unlock_irq(&mdev->al_lock);
 975                 return NULL;
 976         }
 977         e = lc_get(mdev->resync, enr);
 978         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
 979         if (bm_ext) {
 980                 if (bm_ext->lce.lc_number != enr) {
 981                         bm_ext->rs_left = drbd_bm_e_weight(mdev, enr);
 982                         bm_ext->rs_failed = 0;
 983                         lc_committed(mdev->resync);
 984                         wakeup = 1;
 985                 }
 986                 if (bm_ext->lce.refcnt == 1)
 987                         mdev->resync_locked++;
 988                 set_bit(BME_NO_WRITES, &bm_ext->flags);
 989         }
 990         rs_flags = mdev->resync->flags;
 991         spin_unlock_irq(&mdev->al_lock);
 992         if (wakeup)
 993                 wake_up(&mdev->al_wait);
 994
 995         if (!bm_ext) {
 996                 if (rs_flags & LC_STARVING)
 997                         dev_warn(DEV, "Have to wait for element"
 998                              " (resync LRU too small?)\n");
 999                 BUG_ON(rs_flags & LC_LOCKED);
1000         }
1001
1002         return bm_ext;
1003 }
1004
1005 static int _is_in_al(struct drbd_conf *mdev, unsigned int enr)
1006 {
1007         int rv;
1008
1009         spin_lock_irq(&mdev->al_lock);
1010         rv = lc_is_used(mdev->act_log, enr);
1011         spin_unlock_irq(&mdev->al_lock);
1012
1013         return rv;
1014 }
1015
1016 /**
1017  * drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED
1018  * @mdev:       DRBD device.
1019  * @sector:     The sector number.
1020  *
1021  * This functions sleeps on al_wait. Returns 0 on success, -EINTR if interrupted.
1022  */
1023 int drbd_rs_begin_io(struct drbd_conf *mdev, sector_t sector)
1024 {
1025         unsigned int enr = BM_SECT_TO_EXT(sector);
1026         struct bm_extent *bm_ext;
1027         int i, sig;
1028         int sa = 200; /* Step aside 200 times, then grab the extent and let app-IO wait.
1029                          200 times -> 20 seconds. */
1030
1031 retry:
1032         sig = wait_event_interruptible(mdev->al_wait,
1033                         (bm_ext = _bme_get(mdev, enr)));
1034         if (sig)
1035                 return -EINTR;
1036
1037         if (test_bit(BME_LOCKED, &bm_ext->flags))
1038                 return 0;
1039
1040         for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
1041                 sig = wait_event_interruptible(mdev->al_wait,
1042                                                !_is_in_al(mdev, enr * AL_EXT_PER_BM_SECT + i) ||
1043                                                test_bit(BME_PRIORITY, &bm_ext->flags));
1044
1045                 if (sig || (test_bit(BME_PRIORITY, &bm_ext->flags) && sa)) {
1046                         spin_lock_irq(&mdev->al_lock);
1047                         if (lc_put(mdev->resync, &bm_ext->lce) == 0) {
1048                                 bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */
1049                                 mdev->resync_locked--;
1050                                 wake_up(&mdev->al_wait);
1051                         }
1052                         spin_unlock_irq(&mdev->al_lock);
1053                         if (sig)
1054                                 return -EINTR;
1055                         if (schedule_timeout_interruptible(HZ/10))
1056                                 return -EINTR;
1057                         if (sa && --sa == 0)
1058                                 dev_warn(DEV,"drbd_rs_begin_io() stepped aside for 20sec."
1059                                          "Resync stalled?\n");
1060                         goto retry;
1061                 }
1062         }
1063         set_bit(BME_LOCKED, &bm_ext->flags);
1064         return 0;
1065 }
1066
1067 /**
1068  * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
1069  * @mdev:       DRBD device.
1070  * @sector:     The sector number.
1071  *
1072  * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
1073  * tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN
1074  * if there is still application IO going on in this area.
1075  */
1076 int drbd_try_rs_begin_io(struct drbd_conf *mdev, sector_t sector)
1077 {
1078         unsigned int enr = BM_SECT_TO_EXT(sector);
1079         const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT;
1080         struct lc_element *e;
1081         struct bm_extent *bm_ext;
1082         int i;
1083
1084         spin_lock_irq(&mdev->al_lock);
1085         if (mdev->resync_wenr != LC_FREE && mdev->resync_wenr != enr) {
1086                 /* in case you have very heavy scattered io, it may
1087                  * stall the syncer undefined if we give up the ref count
1088                  * when we try again and requeue.
1089                  *
1090                  * if we don't give up the refcount, but the next time
1091                  * we are scheduled this extent has been "synced" by new
1092                  * application writes, we'd miss the lc_put on the
1093                  * extent we keep the refcount on.
1094                  * so we remembered which extent we had to try again, and
1095                  * if the next requested one is something else, we do
1096                  * the lc_put here...
1097                  * we also have to wake_up
1098                  */
1099                 e = lc_find(mdev->resync, mdev->resync_wenr);
1100                 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1101                 if (bm_ext) {
1102                         D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
1103                         D_ASSERT(test_bit(BME_NO_WRITES, &bm_ext->flags));
1104                         clear_bit(BME_NO_WRITES, &bm_ext->flags);
1105                         mdev->resync_wenr = LC_FREE;
1106                         if (lc_put(mdev->resync, &bm_ext->lce) == 0)
1107                                 mdev->resync_locked--;
1108                         wake_up(&mdev->al_wait);
1109                 } else {
1110                         dev_alert(DEV, "LOGIC BUG\n");
1111                 }
1112         }
1113         /* TRY. */
1114         e = lc_try_get(mdev->resync, enr);
1115         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1116         if (bm_ext) {
1117                 if (test_bit(BME_LOCKED, &bm_ext->flags))
1118                         goto proceed;
1119                 if (!test_and_set_bit(BME_NO_WRITES, &bm_ext->flags)) {
1120                         mdev->resync_locked++;
1121                 } else {
1122                         /* we did set the BME_NO_WRITES,
1123                          * but then could not set BME_LOCKED,
1124                          * so we tried again.
1125                          * drop the extra reference. */
1126                         bm_ext->lce.refcnt--;
1127                         D_ASSERT(bm_ext->lce.refcnt > 0);
1128                 }
1129                 goto check_al;
1130         } else {
1131                 /* do we rather want to try later? */
1132                 if (mdev->resync_locked > mdev->resync->nr_elements-3)
1133                         goto try_again;
1134                 /* Do or do not. There is no try. -- Yoda */
1135                 e = lc_get(mdev->resync, enr);
1136                 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1137                 if (!bm_ext) {
1138                         const unsigned long rs_flags = mdev->resync->flags;
1139                         if (rs_flags & LC_STARVING)
1140                                 dev_warn(DEV, "Have to wait for element"
1141                                      " (resync LRU too small?)\n");
1142                         BUG_ON(rs_flags & LC_LOCKED);
1143                         goto try_again;
1144                 }
1145                 if (bm_ext->lce.lc_number != enr) {
1146                         bm_ext->rs_left = drbd_bm_e_weight(mdev, enr);
1147                         bm_ext->rs_failed = 0;
1148                         lc_committed(mdev->resync);
1149                         wake_up(&mdev->al_wait);
1150                         D_ASSERT(test_bit(BME_LOCKED, &bm_ext->flags) == 0);
1151                 }
1152                 set_bit(BME_NO_WRITES, &bm_ext->flags);
1153                 D_ASSERT(bm_ext->lce.refcnt == 1);
1154                 mdev->resync_locked++;
1155                 goto check_al;
1156         }
1157 check_al:
1158         for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
1159                 if (lc_is_used(mdev->act_log, al_enr+i))
1160                         goto try_again;
1161         }
1162         set_bit(BME_LOCKED, &bm_ext->flags);
1163 proceed:
1164         mdev->resync_wenr = LC_FREE;
1165         spin_unlock_irq(&mdev->al_lock);
1166         return 0;
1167
1168 try_again:
1169         if (bm_ext)
1170                 mdev->resync_wenr = enr;
1171         spin_unlock_irq(&mdev->al_lock);
1172         return -EAGAIN;
1173 }
1174
1175 void drbd_rs_complete_io(struct drbd_conf *mdev, sector_t sector)
1176 {
1177         unsigned int enr = BM_SECT_TO_EXT(sector);
1178         struct lc_element *e;
1179         struct bm_extent *bm_ext;
1180         unsigned long flags;
1181
1182         spin_lock_irqsave(&mdev->al_lock, flags);
1183         e = lc_find(mdev->resync, enr);
1184         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1185         if (!bm_ext) {
1186                 spin_unlock_irqrestore(&mdev->al_lock, flags);
1187                 if (__ratelimit(&drbd_ratelimit_state))
1188                         dev_err(DEV, "drbd_rs_complete_io() called, but extent not found\n");
1189                 return;
1190         }
1191
1192         if (bm_ext->lce.refcnt == 0) {
1193                 spin_unlock_irqrestore(&mdev->al_lock, flags);
1194                 dev_err(DEV, "drbd_rs_complete_io(,%llu [=%u]) called, "
1195                     "but refcnt is 0!?\n",
1196                     (unsigned long long)sector, enr);
1197                 return;
1198         }
1199
1200         if (lc_put(mdev->resync, &bm_ext->lce) == 0) {
1201                 bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */
1202                 mdev->resync_locked--;
1203                 wake_up(&mdev->al_wait);
1204         }
1205
1206         spin_unlock_irqrestore(&mdev->al_lock, flags);
1207 }
1208
1209 /**
1210  * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
1211  * @mdev:       DRBD device.
1212  */
1213 void drbd_rs_cancel_all(struct drbd_conf *mdev)
1214 {
1215         spin_lock_irq(&mdev->al_lock);
1216
1217         if (get_ldev_if_state(mdev, D_FAILED)) { /* Makes sure ->resync is there. */
1218                 lc_reset(mdev->resync);
1219                 put_ldev(mdev);
1220         }
1221         mdev->resync_locked = 0;
1222         mdev->resync_wenr = LC_FREE;
1223         spin_unlock_irq(&mdev->al_lock);
1224         wake_up(&mdev->al_wait);
1225 }
1226
1227 /**
1228  * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
1229  * @mdev:       DRBD device.
1230  *
1231  * Returns 0 upon success, -EAGAIN if at least one reference count was
1232  * not zero.
1233  */
1234 int drbd_rs_del_all(struct drbd_conf *mdev)
1235 {
1236         struct lc_element *e;
1237         struct bm_extent *bm_ext;
1238         int i;
1239
1240         spin_lock_irq(&mdev->al_lock);
1241
1242         if (get_ldev_if_state(mdev, D_FAILED)) {
1243                 /* ok, ->resync is there. */
1244                 for (i = 0; i < mdev->resync->nr_elements; i++) {
1245                         e = lc_element_by_index(mdev->resync, i);
1246                         bm_ext = lc_entry(e, struct bm_extent, lce);
1247                         if (bm_ext->lce.lc_number == LC_FREE)
1248                                 continue;
1249                         if (bm_ext->lce.lc_number == mdev->resync_wenr) {
1250                                 dev_info(DEV, "dropping %u in drbd_rs_del_all, apparently"
1251                                      " got 'synced' by application io\n",
1252                                      mdev->resync_wenr);
1253                                 D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
1254                                 D_ASSERT(test_bit(BME_NO_WRITES, &bm_ext->flags));
1255                                 clear_bit(BME_NO_WRITES, &bm_ext->flags);
1256                                 mdev->resync_wenr = LC_FREE;
1257                                 lc_put(mdev->resync, &bm_ext->lce);
1258                         }
1259                         if (bm_ext->lce.refcnt != 0) {
1260                                 dev_info(DEV, "Retrying drbd_rs_del_all() later. "
1261                                      "refcnt=%d\n", bm_ext->lce.refcnt);
1262                                 put_ldev(mdev);
1263                                 spin_unlock_irq(&mdev->al_lock);
1264                                 return -EAGAIN;
1265                         }
1266                         D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
1267                         D_ASSERT(!test_bit(BME_NO_WRITES, &bm_ext->flags));
1268                         lc_del(mdev->resync, &bm_ext->lce);
1269                 }
1270                 D_ASSERT(mdev->resync->used == 0);
1271                 put_ldev(mdev);
1272         }
1273         spin_unlock_irq(&mdev->al_lock);
1274
1275         return 0;
1276 }
1277
1278 /**
1279  * drbd_rs_failed_io() - Record information on a failure to resync the specified blocks
1280  * @mdev:       DRBD device.
1281  * @sector:     The sector number.
1282  * @size:       Size of failed IO operation, in byte.
1283  */
1284 void drbd_rs_failed_io(struct drbd_conf *mdev, sector_t sector, int size)
1285 {
1286         /* Is called from worker and receiver context _only_ */
1287         unsigned long sbnr, ebnr, lbnr;
1288         unsigned long count;
1289         sector_t esector, nr_sectors;
1290         int wake_up = 0;
1291
1292         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
1293                 dev_err(DEV, "drbd_rs_failed_io: sector=%llus size=%d nonsense!\n",
1294                                 (unsigned long long)sector, size);
1295                 return;
1296         }
1297         nr_sectors = drbd_get_capacity(mdev->this_bdev);
1298         esector = sector + (size >> 9) - 1;
1299
1300         if (!expect(sector < nr_sectors))
1301                 return;
1302         if (!expect(esector < nr_sectors))
1303                 esector = nr_sectors - 1;
1304
1305         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
1306
1307         /*
1308          * round up start sector, round down end sector.  we make sure we only
1309          * handle full, aligned, BM_BLOCK_SIZE (4K) blocks */
1310         if (unlikely(esector < BM_SECT_PER_BIT-1))
1311                 return;
1312         if (unlikely(esector == (nr_sectors-1)))
1313                 ebnr = lbnr;
1314         else
1315                 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
1316         sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
1317
1318         if (sbnr > ebnr)
1319                 return;
1320
1321         /*
1322          * ok, (capacity & 7) != 0 sometimes, but who cares...
1323          * we count rs_{total,left} in bits, not sectors.
1324          */
1325         spin_lock_irq(&mdev->al_lock);
1326         count = drbd_bm_count_bits(mdev, sbnr, ebnr);
1327         if (count) {
1328                 mdev->rs_failed += count;
1329
1330                 if (get_ldev(mdev)) {
1331                         drbd_try_clear_on_disk_bm(mdev, sector, count, false);
1332                         put_ldev(mdev);
1333                 }
1334
1335                 /* just wake_up unconditional now, various lc_chaged(),
1336                  * lc_put() in drbd_try_clear_on_disk_bm(). */
1337                 wake_up = 1;
1338         }
1339         spin_unlock_irq(&mdev->al_lock);
1340         if (wake_up)
1341                 wake_up(&mdev->al_wait);
1342 }