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 struct drbd_atodb_wait {
 108         atomic_t           count;
 109         struct completion  io_done;
 110         struct drbd_conf   *mdev;
 111         int                error;
 112 };
 113
 114
 115 static int w_al_write_transaction(struct drbd_work *, int);
 116
 117 static int _drbd_md_sync_page_io(struct drbd_conf *mdev,
 118                                  struct drbd_backing_dev *bdev,
 119                                  struct page *page, sector_t sector,
 120                                  int rw, int size)
 121 {
 122         struct bio *bio;
 123         struct drbd_md_io md_io;
 124         int err;
 125
 126         md_io.mdev = mdev;
 127         init_completion(&md_io.event);
 128         md_io.error = 0;
 129
 130         if ((rw & WRITE) && !test_bit(MD_NO_FUA, &mdev->flags))
 131                 rw |= REQ_FUA | REQ_FLUSH;
 132         rw |= REQ_SYNC;
 133
 134         bio = bio_alloc_drbd(GFP_NOIO);
 135         bio->bi_bdev = bdev->md_bdev;
 136         bio->bi_sector = sector;
 137         err = -EIO;
 138         if (bio_add_page(bio, page, size, 0) != size)
 139                 goto out;
 140         bio->bi_private = &md_io;
 141         bio->bi_end_io = drbd_md_io_complete;
 142         bio->bi_rw = rw;
 143
 144         if (drbd_insert_fault(mdev, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
 145                 bio_endio(bio, -EIO);
 146         else
 147                 submit_bio(rw, bio);
 148         wait_for_completion(&md_io.event);
 149         if (bio_flagged(bio, BIO_UPTODATE))
 150                 err = md_io.error;
 151
 152  out:
 153         bio_put(bio);
 154         return err;
 155 }
 156
 157 int drbd_md_sync_page_io(struct drbd_conf *mdev, struct drbd_backing_dev *bdev,
 158                          sector_t sector, int rw)
 159 {
 160         int err;
 161         struct page *iop = mdev->md_io_page;
 162
 163         D_ASSERT(mutex_is_locked(&mdev->md_io_mutex));
 164
 165         BUG_ON(!bdev->md_bdev);
 166
 167         dev_dbg(DEV, "meta_data io: %s [%d]:%s(,%llus,%s)\n",
 168              current->comm, current->pid, __func__,
 169              (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
 170
 171         if (sector < drbd_md_first_sector(bdev) ||
 172             sector + 7 > drbd_md_last_sector(bdev))
 173                 dev_alert(DEV, "%s [%d]:%s(,%llus,%s) out of range md access!\n",
 174                      current->comm, current->pid, __func__,
 175                      (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
 176
 177         err = _drbd_md_sync_page_io(mdev, bdev, iop, sector, rw, MD_BLOCK_SIZE);
 178         if (err) {
 179                 dev_err(DEV, "drbd_md_sync_page_io(,%llus,%s) failed!\n",
 180                     (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
 181         }
 182         return err;
 183 }
 184
 185 static struct lc_element *_al_get(struct drbd_conf *mdev, unsigned int enr)
 186 {
 187         struct lc_element *al_ext;
 188         struct lc_element *tmp;
 189         int wake;
 190
 191         spin_lock_irq(&mdev->al_lock);
 192         tmp = lc_find(mdev->resync, enr/AL_EXT_PER_BM_SECT);
 193         if (unlikely(tmp != NULL)) {
 194                 struct bm_extent  *bm_ext = lc_entry(tmp, struct bm_extent, lce);
 195                 if (test_bit(BME_NO_WRITES, &bm_ext->flags)) {
 196                         wake = !test_and_set_bit(BME_PRIORITY, &bm_ext->flags);
 197                         spin_unlock_irq(&mdev->al_lock);
 198                         if (wake)
 199                                 wake_up(&mdev->al_wait);
 200                         return NULL;
 201                 }
 202         }
 203         al_ext = lc_get(mdev->act_log, enr);
 204         spin_unlock_irq(&mdev->al_lock);
 205         return al_ext;
 206 }
 207
 208 void drbd_al_begin_io(struct drbd_conf *mdev, sector_t sector)
 209 {
 210         unsigned int enr = (sector >> (AL_EXTENT_SHIFT-9));
 211         struct lc_element *al_ext;
 212         struct update_al_work al_work;
 213
 214         D_ASSERT(atomic_read(&mdev->local_cnt) > 0);
 215
 216         wait_event(mdev->al_wait, (al_ext = _al_get(mdev, enr)));
 217
 218         if (al_ext->lc_number != enr) {
 219                 /* drbd_al_write_transaction(mdev,al_ext,enr);
 220                  * recurses into generic_make_request(), which
 221                  * disallows recursion, bios being serialized on the
 222                  * current->bio_tail list now.
 223                  * we have to delegate updates to the activity log
 224                  * to the worker thread. */
 225
 226                 /* Serialize multiple transactions.
 227                  * This uses test_and_set_bit, memory barrier is implicit.
 228                  * Optimization potential:
 229                  * first check for transaction number > old transaction number,
 230                  * so not all waiters have to lock/unlock.  */
 231                 wait_event(mdev->al_wait, lc_try_lock_for_transaction(mdev->act_log));
 232
 233                 /* Double check: it may have been committed by someone else,
 234                  * while we have been waiting for the lock. */
 235                 if (al_ext->lc_number != enr) {
 236                         init_completion(&al_work.event);
 237                         al_work.w.cb = w_al_write_transaction;
 238                         al_work.w.mdev = mdev;
 239                         drbd_queue_work_front(&mdev->tconn->data.work, &al_work.w);
 240                         wait_for_completion(&al_work.event);
 241
 242                         mdev->al_writ_cnt++;
 243
 244                         spin_lock_irq(&mdev->al_lock);
 245                         /* FIXME
 246                         if (al_work.err)
 247                                 we need an "lc_cancel" here;
 248                         */
 249                         lc_committed(mdev->act_log);
 250                         spin_unlock_irq(&mdev->al_lock);
 251                 }
 252                 lc_unlock(mdev->act_log);
 253                 wake_up(&mdev->al_wait);
 254         }
 255 }
 256
 257 void drbd_al_complete_io(struct drbd_conf *mdev, sector_t sector)
 258 {
 259         unsigned int enr = (sector >> (AL_EXTENT_SHIFT-9));
 260         struct lc_element *extent;
 261         unsigned long flags;
 262
 263         spin_lock_irqsave(&mdev->al_lock, flags);
 264
 265         extent = lc_find(mdev->act_log, enr);
 266
 267         if (!extent) {
 268                 spin_unlock_irqrestore(&mdev->al_lock, flags);
 269                 dev_err(DEV, "al_complete_io() called on inactive extent %u\n", enr);
 270                 return;
 271         }
 272
 273         if (lc_put(mdev->act_log, extent) == 0)
 274                 wake_up(&mdev->al_wait);
 275
 276         spin_unlock_irqrestore(&mdev->al_lock, flags);
 277 }
 278
 279 #if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
 280 /* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
 281  * are still coupled, or assume too much about their relation.
 282  * Code below will not work if this is violated.
 283  * Will be cleaned up with some followup patch.
 284  */
 285 # error FIXME
 286 #endif
 287
 288 static unsigned int al_extent_to_bm_page(unsigned int al_enr)
 289 {
 290         return al_enr >>
 291                 /* bit to page */
 292                 ((PAGE_SHIFT + 3) -
 293                 /* al extent number to bit */
 294                  (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
 295 }
 296
 297 static unsigned int rs_extent_to_bm_page(unsigned int rs_enr)
 298 {
 299         return rs_enr >>
 300                 /* bit to page */
 301                 ((PAGE_SHIFT + 3) -
 302                 /* al extent number to bit */
 303                  (BM_EXT_SHIFT - BM_BLOCK_SHIFT));
 304 }
 305
 306 static int
 307 w_al_write_transaction(struct drbd_work *w, int unused)
 308 {
 309         struct update_al_work *aw = container_of(w, struct update_al_work, w);
 310         struct drbd_conf *mdev = w->mdev;
 311         struct al_transaction_on_disk *buffer;
 312         struct lc_element *e;
 313         sector_t sector;
 314         int i, mx;
 315         unsigned extent_nr;
 316         unsigned crc = 0;
 317
 318         if (!get_ldev(mdev)) {
 319                 dev_err(DEV, "disk is %s, cannot start al transaction\n",
 320                         drbd_disk_str(mdev->state.disk));
 321                 aw->err = -EIO;
 322                 complete(&((struct update_al_work *)w)->event);
 323                 return 0;
 324         }
 325
 326         /* The bitmap write may have failed, causing a state change. */
 327         if (mdev->state.disk < D_INCONSISTENT) {
 328                 dev_err(DEV,
 329                         "disk is %s, cannot write al transaction\n",
 330                         drbd_disk_str(mdev->state.disk));
 331                 aw->err = -EIO;
 332                 complete(&((struct update_al_work *)w)->event);
 333                 put_ldev(mdev);
 334                 return 0;
 335         }
 336
 337         mutex_lock(&mdev->md_io_mutex); /* protects md_io_buffer, al_tr_cycle, ... */
 338         buffer = page_address(mdev->md_io_page);
 339
 340         memset(buffer, 0, sizeof(*buffer));
 341         buffer->magic = cpu_to_be32(DRBD_AL_MAGIC);
 342         buffer->tr_number = cpu_to_be32(mdev->al_tr_number);
 343
 344         i = 0;
 345
 346         /* Even though no one can start to change this list
 347          * once we set the LC_LOCKED -- from drbd_al_begin_io(),
 348          * lc_try_lock_for_transaction() --, someone may still
 349          * be in the process of changing it. */
 350         spin_lock_irq(&mdev->al_lock);
 351         list_for_each_entry(e, &mdev->act_log->to_be_changed, list) {
 352                 if (i == AL_UPDATES_PER_TRANSACTION) {
 353                         i++;
 354                         break;
 355                 }
 356                 buffer->update_slot_nr[i] = cpu_to_be16(e->lc_index);
 357                 buffer->update_extent_nr[i] = cpu_to_be32(e->lc_new_number);
 358                 if (e->lc_number != LC_FREE)
 359                         drbd_bm_mark_for_writeout(mdev,
 360                                         al_extent_to_bm_page(e->lc_number));
 361                 i++;
 362         }
 363         spin_unlock_irq(&mdev->al_lock);
 364         BUG_ON(i > AL_UPDATES_PER_TRANSACTION);
 365
 366         buffer->n_updates = cpu_to_be16(i);
 367         for ( ; i < AL_UPDATES_PER_TRANSACTION; i++) {
 368                 buffer->update_slot_nr[i] = cpu_to_be16(-1);
 369                 buffer->update_extent_nr[i] = cpu_to_be32(LC_FREE);
 370         }
 371
 372         buffer->context_size = cpu_to_be16(mdev->act_log->nr_elements);
 373         buffer->context_start_slot_nr = cpu_to_be16(mdev->al_tr_cycle);
 374
 375         mx = min_t(int, AL_CONTEXT_PER_TRANSACTION,
 376                    mdev->act_log->nr_elements - mdev->al_tr_cycle);
 377         for (i = 0; i < mx; i++) {
 378                 unsigned idx = mdev->al_tr_cycle + i;
 379                 extent_nr = lc_element_by_index(mdev->act_log, idx)->lc_number;
 380                 buffer->context[i] = cpu_to_be32(extent_nr);
 381         }
 382         for (; i < AL_CONTEXT_PER_TRANSACTION; i++)
 383                 buffer->context[i] = cpu_to_be32(LC_FREE);
 384
 385         mdev->al_tr_cycle += AL_CONTEXT_PER_TRANSACTION;
 386         if (mdev->al_tr_cycle >= mdev->act_log->nr_elements)
 387                 mdev->al_tr_cycle = 0;
 388
 389         sector =  mdev->ldev->md.md_offset
 390                 + mdev->ldev->md.al_offset
 391                 + mdev->al_tr_pos * (MD_BLOCK_SIZE>>9);
 392
 393         crc = crc32c(0, buffer, 4096);
 394         buffer->crc32c = cpu_to_be32(crc);
 395
 396         if (drbd_bm_write_hinted(mdev))
 397                 aw->err = -EIO;
 398                 /* drbd_chk_io_error done already */
 399         else if (drbd_md_sync_page_io(mdev, mdev->ldev, sector, WRITE)) {
 400                 aw->err = -EIO;
 401                 drbd_chk_io_error(mdev, 1, true);
 402         } else {
 403                 /* advance ringbuffer position and transaction counter */
 404                 mdev->al_tr_pos = (mdev->al_tr_pos + 1) % (MD_AL_SECTORS*512/MD_BLOCK_SIZE);
 405                 mdev->al_tr_number++;
 406         }
 407
 408         mutex_unlock(&mdev->md_io_mutex);
 409         complete(&((struct update_al_work *)w)->event);
 410         put_ldev(mdev);
 411
 412         return 0;
 413 }
 414
 415 /* FIXME
 416  * reading of the activity log,
 417  * and potentially dirtying of the affected bitmap regions,
 418  * should be done from userland only.
 419  * DRBD would simply always attach with an empty activity log,
 420  * and refuse to attach to something that looks like a crashed primary.
 421  */
 422
 423 /**
 424  * drbd_al_read_tr() - Read a single transaction from the on disk activity log
 425  * @mdev:       DRBD device.
 426  * @bdev:       Block device to read form.
 427  * @b:          pointer to an al_transaction.
 428  * @index:      On disk slot of the transaction to read.
 429  *
 430  * Returns -1 on IO error, 0 on checksum error and 1 upon success.
 431  */
 432 static int drbd_al_read_tr(struct drbd_conf *mdev,
 433                            struct drbd_backing_dev *bdev,
 434                            int index)
 435 {
 436         struct al_transaction_on_disk *b = page_address(mdev->md_io_page);
 437         sector_t sector;
 438         u32 crc;
 439
 440         sector =  bdev->md.md_offset
 441                 + bdev->md.al_offset
 442                 + index * (MD_BLOCK_SIZE>>9);
 443
 444         /* Dont process error normally,
 445          * as this is done before disk is attached! */
 446         if (drbd_md_sync_page_io(mdev, bdev, sector, READ))
 447                 return -1;
 448
 449         if (!expect(b->magic == cpu_to_be32(DRBD_AL_MAGIC)))
 450                 return 0;
 451
 452         if (!expect(be16_to_cpu(b->n_updates) <= AL_UPDATES_PER_TRANSACTION))
 453                 return 0;
 454
 455         if (!expect(be16_to_cpu(b->context_size) <= DRBD_AL_EXTENTS_MAX))
 456                 return 0;
 457
 458         if (!expect(be16_to_cpu(b->context_start_slot_nr) < DRBD_AL_EXTENTS_MAX))
 459                 return 0;
 460
 461         crc = be32_to_cpu(b->crc32c);
 462         b->crc32c = 0;
 463         if (!expect(crc == crc32c(0, b, 4096)))
 464                 return 0;
 465
 466         return 1;
 467 }
 468
 469 /**
 470  * drbd_al_read_log() - Restores the activity log from its on disk representation.
 471  * @mdev:       DRBD device.
 472  * @bdev:       Block device to read form.
 473  *
 474  * Returns 1 on success, returns 0 when reading the log failed due to IO errors.
 475  */
 476 int drbd_al_read_log(struct drbd_conf *mdev, struct drbd_backing_dev *bdev)
 477 {
 478         struct al_transaction_on_disk *b;
 479         int i;
 480         int rv;
 481         int mx;
 482         int active_extents = 0;
 483         int transactions = 0;
 484         int found_valid = 0;
 485         int found_initialized = 0;
 486         int from = 0;
 487         int to = 0;
 488         u32 from_tnr = 0;
 489         u32 to_tnr = 0;
 490         u32 cnr;
 491
 492         /* Note that this is expected to be called with a newly created,
 493          * clean and all unused activity log of the "expected size".
 494          */
 495
 496         /* lock out all other meta data io for now,
 497          * and make sure the page is mapped.
 498          */
 499         mutex_lock(&mdev->md_io_mutex);
 500         b = page_address(mdev->md_io_page);
 501
 502         /* Always use the full ringbuffer space for now.
 503          * possible optimization: read in all of it,
 504          * then scan the in-memory pages. */
 505
 506         mx = (MD_AL_SECTORS*512/MD_BLOCK_SIZE);
 507
 508         /* Find the valid transaction in the log */
 509         for (i = 0; i < mx; i++) {
 510                 rv = drbd_al_read_tr(mdev, bdev, i);
 511                 /* invalid data in that block */
 512                 if (rv == 0)
 513                         continue;
 514                 if (be16_to_cpu(b->transaction_type) == AL_TR_INITIALIZED) {
 515                         ++found_initialized;
 516                         continue;
 517                 }
 518
 519                 /* IO error */
 520                 if (rv == -1) {
 521                         mutex_unlock(&mdev->md_io_mutex);
 522                         return 0;
 523                 }
 524
 525                 cnr = be32_to_cpu(b->tr_number);
 526                 if (++found_valid == 1) {
 527                         from = i;
 528                         to = i;
 529                         from_tnr = cnr;
 530                         to_tnr = cnr;
 531                         continue;
 532                 }
 533
 534                 D_ASSERT(cnr != to_tnr);
 535                 D_ASSERT(cnr != from_tnr);
 536                 if ((int)cnr - (int)from_tnr < 0) {
 537                         D_ASSERT(from_tnr - cnr + i - from == mx);
 538                         from = i;
 539                         from_tnr = cnr;
 540                 }
 541                 if ((int)cnr - (int)to_tnr > 0) {
 542                         D_ASSERT(cnr - to_tnr == i - to);
 543                         to = i;
 544                         to_tnr = cnr;
 545                 }
 546         }
 547
 548         if (!found_valid) {
 549                 if (found_initialized != mx)
 550                         dev_warn(DEV, "No usable activity log found.\n");
 551                 mutex_unlock(&mdev->md_io_mutex);
 552                 return 1;
 553         }
 554
 555         /* Read the valid transactions.
 556          * dev_info(DEV, "Reading from %d to %d.\n",from,to); */
 557         i = from;
 558         while (1) {
 559                 struct lc_element *e;
 560                 unsigned j, n, slot, extent_nr;
 561
 562                 rv = drbd_al_read_tr(mdev, bdev, i);
 563                 if (!expect(rv != 0))
 564                         goto cancel;
 565                 if (rv == -1) {
 566                         mutex_unlock(&mdev->md_io_mutex);
 567                         return 0;
 568                 }
 569
 570                 /* deal with different transaction types.
 571                  * not yet implemented */
 572                 if (!expect(b->transaction_type == 0))
 573                         goto cancel;
 574
 575                 /* on the fly re-create/resize activity log?
 576                  * will be a special transaction type flag. */
 577                 if (!expect(be16_to_cpu(b->context_size) == mdev->act_log->nr_elements))
 578                         goto cancel;
 579                 if (!expect(be16_to_cpu(b->context_start_slot_nr) < mdev->act_log->nr_elements))
 580                         goto cancel;
 581
 582                 /* We are the only user of the activity log right now,
 583                  * don't actually need to take that lock. */
 584                 spin_lock_irq(&mdev->al_lock);
 585
 586                 /* first, apply the context, ... */
 587                 for (j = 0, slot = be16_to_cpu(b->context_start_slot_nr);
 588                      j < AL_CONTEXT_PER_TRANSACTION &&
 589                      slot < mdev->act_log->nr_elements; j++, slot++) {
 590                         extent_nr = be32_to_cpu(b->context[j]);
 591                         e = lc_element_by_index(mdev->act_log, slot);
 592                         if (e->lc_number != extent_nr) {
 593                                 if (extent_nr != LC_FREE)
 594                                         active_extents++;
 595                                 else
 596                                         active_extents--;
 597                         }
 598                         lc_set(mdev->act_log, extent_nr, slot);
 599                 }
 600
 601                 /* ... then apply the updates,
 602                  * which override the context information.
 603                  * drbd_al_read_tr already did the rangecheck
 604                  * on n <= AL_UPDATES_PER_TRANSACTION */
 605                 n = be16_to_cpu(b->n_updates);
 606                 for (j = 0; j < n; j++) {
 607                         slot = be16_to_cpu(b->update_slot_nr[j]);
 608                         extent_nr = be32_to_cpu(b->update_extent_nr[j]);
 609                         if (!expect(slot < mdev->act_log->nr_elements))
 610                                 break;
 611                         e = lc_element_by_index(mdev->act_log, slot);
 612                         if (e->lc_number != extent_nr) {
 613                                 if (extent_nr != LC_FREE)
 614                                         active_extents++;
 615                                 else
 616                                         active_extents--;
 617                         }
 618                         lc_set(mdev->act_log, extent_nr, slot);
 619                 }
 620                 spin_unlock_irq(&mdev->al_lock);
 621
 622                 transactions++;
 623
 624 cancel:
 625                 if (i == to)
 626                         break;
 627                 i++;
 628                 if (i >= mx)
 629                         i = 0;
 630         }
 631
 632         mdev->al_tr_number = to_tnr+1;
 633         mdev->al_tr_pos = (to + 1) % (MD_AL_SECTORS*512/MD_BLOCK_SIZE);
 634
 635         /* ok, we are done with it */
 636         mutex_unlock(&mdev->md_io_mutex);
 637
 638         dev_info(DEV, "Found %d transactions (%d active extents) in activity log.\n",
 639              transactions, active_extents);
 640
 641         return 1;
 642 }
 643
 644 /**
 645  * drbd_al_apply_to_bm() - Sets the bitmap to dirty(1) where covered by active AL extents
 646  * @mdev:       DRBD device.
 647  */
 648 void drbd_al_apply_to_bm(struct drbd_conf *mdev)
 649 {
 650         unsigned int enr;
 651         unsigned long add = 0;
 652         char ppb[10];
 653         int i, tmp;
 654
 655         wait_event(mdev->al_wait, lc_try_lock(mdev->act_log));
 656
 657         for (i = 0; i < mdev->act_log->nr_elements; i++) {
 658                 enr = lc_element_by_index(mdev->act_log, i)->lc_number;
 659                 if (enr == LC_FREE)
 660                         continue;
 661                 tmp = drbd_bm_ALe_set_all(mdev, enr);
 662                 dynamic_dev_dbg(DEV, "AL: set %d bits in extent %u\n", tmp, enr);
 663                 add += tmp;
 664         }
 665
 666         lc_unlock(mdev->act_log);
 667         wake_up(&mdev->al_wait);
 668
 669         dev_info(DEV, "Marked additional %s as out-of-sync based on AL.\n",
 670              ppsize(ppb, Bit2KB(add)));
 671 }
 672
 673 static int _try_lc_del(struct drbd_conf *mdev, struct lc_element *al_ext)
 674 {
 675         int rv;
 676
 677         spin_lock_irq(&mdev->al_lock);
 678         rv = (al_ext->refcnt == 0);
 679         if (likely(rv))
 680                 lc_del(mdev->act_log, al_ext);
 681         spin_unlock_irq(&mdev->al_lock);
 682
 683         return rv;
 684 }
 685
 686 /**
 687  * drbd_al_shrink() - Removes all active extents form the activity log
 688  * @mdev:       DRBD device.
 689  *
 690  * Removes all active extents form the activity log, waiting until
 691  * the reference count of each entry dropped to 0 first, of course.
 692  *
 693  * You need to lock mdev->act_log with lc_try_lock() / lc_unlock()
 694  */
 695 void drbd_al_shrink(struct drbd_conf *mdev)
 696 {
 697         struct lc_element *al_ext;
 698         int i;
 699
 700         D_ASSERT(test_bit(__LC_LOCKED, &mdev->act_log->flags));
 701
 702         for (i = 0; i < mdev->act_log->nr_elements; i++) {
 703                 al_ext = lc_element_by_index(mdev->act_log, i);
 704                 if (al_ext->lc_number == LC_FREE)
 705                         continue;
 706                 wait_event(mdev->al_wait, _try_lc_del(mdev, al_ext));
 707         }
 708
 709         wake_up(&mdev->al_wait);
 710 }
 711
 712 static int w_update_odbm(struct drbd_work *w, int unused)
 713 {
 714         struct update_odbm_work *udw = container_of(w, struct update_odbm_work, w);
 715         struct drbd_conf *mdev = w->mdev;
 716         struct sib_info sib = { .sib_reason = SIB_SYNC_PROGRESS, };
 717
 718         if (!get_ldev(mdev)) {
 719                 if (__ratelimit(&drbd_ratelimit_state))
 720                         dev_warn(DEV, "Can not update on disk bitmap, local IO disabled.\n");
 721                 kfree(udw);
 722                 return 0;
 723         }
 724
 725         drbd_bm_write_page(mdev, rs_extent_to_bm_page(udw->enr));
 726         put_ldev(mdev);
 727
 728         kfree(udw);
 729
 730         if (drbd_bm_total_weight(mdev) <= mdev->rs_failed) {
 731                 switch (mdev->state.conn) {
 732                 case C_SYNC_SOURCE:  case C_SYNC_TARGET:
 733                 case C_PAUSED_SYNC_S: case C_PAUSED_SYNC_T:
 734                         drbd_resync_finished(mdev);
 735                 default:
 736                         /* nothing to do */
 737                         break;
 738                 }
 739         }
 740         drbd_bcast_event(mdev, &sib);
 741
 742         return 0;
 743 }
 744
 745
 746 /* ATTENTION. The AL's extents are 4MB each, while the extents in the
 747  * resync LRU-cache are 16MB each.
 748  * The caller of this function has to hold an get_ldev() reference.
 749  *
 750  * TODO will be obsoleted once we have a caching lru of the on disk bitmap
 751  */
 752 static void drbd_try_clear_on_disk_bm(struct drbd_conf *mdev, sector_t sector,
 753                                       int count, int success)
 754 {
 755         struct lc_element *e;
 756         struct update_odbm_work *udw;
 757
 758         unsigned int enr;
 759
 760         D_ASSERT(atomic_read(&mdev->local_cnt));
 761
 762         /* I simply assume that a sector/size pair never crosses
 763          * a 16 MB extent border. (Currently this is true...) */
 764         enr = BM_SECT_TO_EXT(sector);
 765
 766         e = lc_get(mdev->resync, enr);
 767         if (e) {
 768                 struct bm_extent *ext = lc_entry(e, struct bm_extent, lce);
 769                 if (ext->lce.lc_number == enr) {
 770                         if (success)
 771                                 ext->rs_left -= count;
 772                         else
 773                                 ext->rs_failed += count;
 774                         if (ext->rs_left < ext->rs_failed) {
 775                                 dev_err(DEV, "BAD! sector=%llus enr=%u rs_left=%d "
 776                                     "rs_failed=%d count=%d\n",
 777                                      (unsigned long long)sector,
 778                                      ext->lce.lc_number, ext->rs_left,
 779                                      ext->rs_failed, count);
 780                                 dump_stack();
 781
 782                                 lc_put(mdev->resync, &ext->lce);
 783                                 conn_request_state(mdev->tconn, NS(conn, C_DISCONNECTING), CS_HARD);
 784                                 return;
 785                         }
 786                 } else {
 787                         /* Normally this element should be in the cache,
 788                          * since drbd_rs_begin_io() pulled it already in.
 789                          *
 790                          * But maybe an application write finished, and we set
 791                          * something outside the resync lru_cache in sync.
 792                          */
 793                         int rs_left = drbd_bm_e_weight(mdev, enr);
 794                         if (ext->flags != 0) {
 795                                 dev_warn(DEV, "changing resync lce: %d[%u;%02lx]"
 796                                      " -> %d[%u;00]\n",
 797                                      ext->lce.lc_number, ext->rs_left,
 798                                      ext->flags, enr, rs_left);
 799                                 ext->flags = 0;
 800                         }
 801                         if (ext->rs_failed) {
 802                                 dev_warn(DEV, "Kicking resync_lru element enr=%u "
 803                                      "out with rs_failed=%d\n",
 804                                      ext->lce.lc_number, ext->rs_failed);
 805                         }
 806                         ext->rs_left = rs_left;
 807                         ext->rs_failed = success ? 0 : count;
 808                         /* we don't keep a persistent log of the resync lru,
 809                          * we can commit any change right away. */
 810                         lc_committed(mdev->resync);
 811                 }
 812                 lc_put(mdev->resync, &ext->lce);
 813                 /* no race, we are within the al_lock! */
 814
 815                 if (ext->rs_left == ext->rs_failed) {
 816                         ext->rs_failed = 0;
 817
 818                         udw = kmalloc(sizeof(*udw), GFP_ATOMIC);
 819                         if (udw) {
 820                                 udw->enr = ext->lce.lc_number;
 821                                 udw->w.cb = w_update_odbm;
 822                                 udw->w.mdev = mdev;
 823                                 drbd_queue_work_front(&mdev->tconn->data.work, &udw->w);
 824                         } else {
 825                                 dev_warn(DEV, "Could not kmalloc an udw\n");
 826                         }
 827                 }
 828         } else {
 829                 dev_err(DEV, "lc_get() failed! locked=%d/%d flags=%lu\n",
 830                     mdev->resync_locked,
 831                     mdev->resync->nr_elements,
 832                     mdev->resync->flags);
 833         }
 834 }
 835
 836 void drbd_advance_rs_marks(struct drbd_conf *mdev, unsigned long still_to_go)
 837 {
 838         unsigned long now = jiffies;
 839         unsigned long last = mdev->rs_mark_time[mdev->rs_last_mark];
 840         int next = (mdev->rs_last_mark + 1) % DRBD_SYNC_MARKS;
 841         if (time_after_eq(now, last + DRBD_SYNC_MARK_STEP)) {
 842                 if (mdev->rs_mark_left[mdev->rs_last_mark] != still_to_go &&
 843                     mdev->state.conn != C_PAUSED_SYNC_T &&
 844                     mdev->state.conn != C_PAUSED_SYNC_S) {
 845                         mdev->rs_mark_time[next] = now;
 846                         mdev->rs_mark_left[next] = still_to_go;
 847                         mdev->rs_last_mark = next;
 848                 }
 849         }
 850 }
 851
 852 /* clear the bit corresponding to the piece of storage in question:
 853  * size byte of data starting from sector.  Only clear a bits of the affected
 854  * one ore more _aligned_ BM_BLOCK_SIZE blocks.
 855  *
 856  * called by worker on C_SYNC_TARGET and receiver on SyncSource.
 857  *
 858  */
 859 void __drbd_set_in_sync(struct drbd_conf *mdev, sector_t sector, int size,
 860                        const char *file, const unsigned int line)
 861 {
 862         /* Is called from worker and receiver context _only_ */
 863         unsigned long sbnr, ebnr, lbnr;
 864         unsigned long count = 0;
 865         sector_t esector, nr_sectors;
 866         int wake_up = 0;
 867         unsigned long flags;
 868
 869         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
 870                 dev_err(DEV, "drbd_set_in_sync: sector=%llus size=%d nonsense!\n",
 871                                 (unsigned long long)sector, size);
 872                 return;
 873         }
 874         nr_sectors = drbd_get_capacity(mdev->this_bdev);
 875         esector = sector + (size >> 9) - 1;
 876
 877         if (!expect(sector < nr_sectors))
 878                 return;
 879         if (!expect(esector < nr_sectors))
 880                 esector = nr_sectors - 1;
 881
 882         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
 883
 884         /* we clear it (in sync).
 885          * round up start sector, round down end sector.  we make sure we only
 886          * clear full, aligned, BM_BLOCK_SIZE (4K) blocks */
 887         if (unlikely(esector < BM_SECT_PER_BIT-1))
 888                 return;
 889         if (unlikely(esector == (nr_sectors-1)))
 890                 ebnr = lbnr;
 891         else
 892                 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
 893         sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
 894
 895         if (sbnr > ebnr)
 896                 return;
 897
 898         /*
 899          * ok, (capacity & 7) != 0 sometimes, but who cares...
 900          * we count rs_{total,left} in bits, not sectors.
 901          */
 902         count = drbd_bm_clear_bits(mdev, sbnr, ebnr);
 903         if (count && get_ldev(mdev)) {
 904                 drbd_advance_rs_marks(mdev, drbd_bm_total_weight(mdev));
 905                 spin_lock_irqsave(&mdev->al_lock, flags);
 906                 drbd_try_clear_on_disk_bm(mdev, sector, count, true);
 907                 spin_unlock_irqrestore(&mdev->al_lock, flags);
 908
 909                 /* just wake_up unconditional now, various lc_chaged(),
 910                  * lc_put() in drbd_try_clear_on_disk_bm(). */
 911                 wake_up = 1;
 912                 put_ldev(mdev);
 913         }
 914         if (wake_up)
 915                 wake_up(&mdev->al_wait);
 916 }
 917
 918 /*
 919  * this is intended to set one request worth of data out of sync.
 920  * affects at least 1 bit,
 921  * and at most 1+DRBD_MAX_BIO_SIZE/BM_BLOCK_SIZE bits.
 922  *
 923  * called by tl_clear and drbd_send_dblock (==drbd_make_request).
 924  * so this can be _any_ process.
 925  */
 926 int __drbd_set_out_of_sync(struct drbd_conf *mdev, sector_t sector, int size,
 927                             const char *file, const unsigned int line)
 928 {
 929         unsigned long sbnr, ebnr, lbnr, flags;
 930         sector_t esector, nr_sectors;
 931         unsigned int enr, count = 0;
 932         struct lc_element *e;
 933
 934         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
 935                 dev_err(DEV, "sector: %llus, size: %d\n",
 936                         (unsigned long long)sector, size);
 937                 return 0;
 938         }
 939
 940         if (!get_ldev(mdev))
 941                 return 0; /* no disk, no metadata, no bitmap to set bits in */
 942
 943         nr_sectors = drbd_get_capacity(mdev->this_bdev);
 944         esector = sector + (size >> 9) - 1;
 945
 946         if (!expect(sector < nr_sectors))
 947                 goto out;
 948         if (!expect(esector < nr_sectors))
 949                 esector = nr_sectors - 1;
 950
 951         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
 952
 953         /* we set it out of sync,
 954          * we do not need to round anything here */
 955         sbnr = BM_SECT_TO_BIT(sector);
 956         ebnr = BM_SECT_TO_BIT(esector);
 957
 958         /* ok, (capacity & 7) != 0 sometimes, but who cares...
 959          * we count rs_{total,left} in bits, not sectors.  */
 960         spin_lock_irqsave(&mdev->al_lock, flags);
 961         count = drbd_bm_set_bits(mdev, sbnr, ebnr);
 962
 963         enr = BM_SECT_TO_EXT(sector);
 964         e = lc_find(mdev->resync, enr);
 965         if (e)
 966                 lc_entry(e, struct bm_extent, lce)->rs_left += count;
 967         spin_unlock_irqrestore(&mdev->al_lock, flags);
 968
 969 out:
 970         put_ldev(mdev);
 971
 972         return count;
 973 }
 974
 975 static
 976 struct bm_extent *_bme_get(struct drbd_conf *mdev, unsigned int enr)
 977 {
 978         struct lc_element *e;
 979         struct bm_extent *bm_ext;
 980         int wakeup = 0;
 981         unsigned long rs_flags;
 982
 983         spin_lock_irq(&mdev->al_lock);
 984         if (mdev->resync_locked > mdev->resync->nr_elements/2) {
 985                 spin_unlock_irq(&mdev->al_lock);
 986                 return NULL;
 987         }
 988         e = lc_get(mdev->resync, enr);
 989         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
 990         if (bm_ext) {
 991                 if (bm_ext->lce.lc_number != enr) {
 992                         bm_ext->rs_left = drbd_bm_e_weight(mdev, enr);
 993                         bm_ext->rs_failed = 0;
 994                         lc_committed(mdev->resync);
 995                         wakeup = 1;
 996                 }
 997                 if (bm_ext->lce.refcnt == 1)
 998                         mdev->resync_locked++;
 999                 set_bit(BME_NO_WRITES, &bm_ext->flags);
1000         }
1001         rs_flags = mdev->resync->flags;
1002         spin_unlock_irq(&mdev->al_lock);
1003         if (wakeup)
1004                 wake_up(&mdev->al_wait);
1005
1006         if (!bm_ext) {
1007                 if (rs_flags & LC_STARVING)
1008                         dev_warn(DEV, "Have to wait for element"
1009                              " (resync LRU too small?)\n");
1010                 BUG_ON(rs_flags & LC_LOCKED);
1011         }
1012
1013         return bm_ext;
1014 }
1015
1016 static int _is_in_al(struct drbd_conf *mdev, unsigned int enr)
1017 {
1018         int rv;
1019
1020         spin_lock_irq(&mdev->al_lock);
1021         rv = lc_is_used(mdev->act_log, enr);
1022         spin_unlock_irq(&mdev->al_lock);
1023
1024         return rv;
1025 }
1026
1027 /**
1028  * drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED
1029  * @mdev:       DRBD device.
1030  * @sector:     The sector number.
1031  *
1032  * This functions sleeps on al_wait. Returns 0 on success, -EINTR if interrupted.
1033  */
1034 int drbd_rs_begin_io(struct drbd_conf *mdev, sector_t sector)
1035 {
1036         unsigned int enr = BM_SECT_TO_EXT(sector);
1037         struct bm_extent *bm_ext;
1038         int i, sig;
1039         int sa = 200; /* Step aside 200 times, then grab the extent and let app-IO wait.
1040                          200 times -> 20 seconds. */
1041
1042 retry:
1043         sig = wait_event_interruptible(mdev->al_wait,
1044                         (bm_ext = _bme_get(mdev, enr)));
1045         if (sig)
1046                 return -EINTR;
1047
1048         if (test_bit(BME_LOCKED, &bm_ext->flags))
1049                 return 0;
1050
1051         for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
1052                 sig = wait_event_interruptible(mdev->al_wait,
1053                                                !_is_in_al(mdev, enr * AL_EXT_PER_BM_SECT + i) ||
1054                                                test_bit(BME_PRIORITY, &bm_ext->flags));
1055
1056                 if (sig || (test_bit(BME_PRIORITY, &bm_ext->flags) && sa)) {
1057                         spin_lock_irq(&mdev->al_lock);
1058                         if (lc_put(mdev->resync, &bm_ext->lce) == 0) {
1059                                 bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */
1060                                 mdev->resync_locked--;
1061                                 wake_up(&mdev->al_wait);
1062                         }
1063                         spin_unlock_irq(&mdev->al_lock);
1064                         if (sig)
1065                                 return -EINTR;
1066                         if (schedule_timeout_interruptible(HZ/10))
1067                                 return -EINTR;
1068                         if (sa && --sa == 0)
1069                                 dev_warn(DEV,"drbd_rs_begin_io() stepped aside for 20sec."
1070                                          "Resync stalled?\n");
1071                         goto retry;
1072                 }
1073         }
1074         set_bit(BME_LOCKED, &bm_ext->flags);
1075         return 0;
1076 }
1077
1078 /**
1079  * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
1080  * @mdev:       DRBD device.
1081  * @sector:     The sector number.
1082  *
1083  * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
1084  * tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN
1085  * if there is still application IO going on in this area.
1086  */
1087 int drbd_try_rs_begin_io(struct drbd_conf *mdev, sector_t sector)
1088 {
1089         unsigned int enr = BM_SECT_TO_EXT(sector);
1090         const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT;
1091         struct lc_element *e;
1092         struct bm_extent *bm_ext;
1093         int i;
1094
1095         spin_lock_irq(&mdev->al_lock);
1096         if (mdev->resync_wenr != LC_FREE && mdev->resync_wenr != enr) {
1097                 /* in case you have very heavy scattered io, it may
1098                  * stall the syncer undefined if we give up the ref count
1099                  * when we try again and requeue.
1100                  *
1101                  * if we don't give up the refcount, but the next time
1102                  * we are scheduled this extent has been "synced" by new
1103                  * application writes, we'd miss the lc_put on the
1104                  * extent we keep the refcount on.
1105                  * so we remembered which extent we had to try again, and
1106                  * if the next requested one is something else, we do
1107                  * the lc_put here...
1108                  * we also have to wake_up
1109                  */
1110                 e = lc_find(mdev->resync, mdev->resync_wenr);
1111                 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1112                 if (bm_ext) {
1113                         D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
1114                         D_ASSERT(test_bit(BME_NO_WRITES, &bm_ext->flags));
1115                         clear_bit(BME_NO_WRITES, &bm_ext->flags);
1116                         mdev->resync_wenr = LC_FREE;
1117                         if (lc_put(mdev->resync, &bm_ext->lce) == 0)
1118                                 mdev->resync_locked--;
1119                         wake_up(&mdev->al_wait);
1120                 } else {
1121                         dev_alert(DEV, "LOGIC BUG\n");
1122                 }
1123         }
1124         /* TRY. */
1125         e = lc_try_get(mdev->resync, enr);
1126         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1127         if (bm_ext) {
1128                 if (test_bit(BME_LOCKED, &bm_ext->flags))
1129                         goto proceed;
1130                 if (!test_and_set_bit(BME_NO_WRITES, &bm_ext->flags)) {
1131                         mdev->resync_locked++;
1132                 } else {
1133                         /* we did set the BME_NO_WRITES,
1134                          * but then could not set BME_LOCKED,
1135                          * so we tried again.
1136                          * drop the extra reference. */
1137                         bm_ext->lce.refcnt--;
1138                         D_ASSERT(bm_ext->lce.refcnt > 0);
1139                 }
1140                 goto check_al;
1141         } else {
1142                 /* do we rather want to try later? */
1143                 if (mdev->resync_locked > mdev->resync->nr_elements-3)
1144                         goto try_again;
1145                 /* Do or do not. There is no try. -- Yoda */
1146                 e = lc_get(mdev->resync, enr);
1147                 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1148                 if (!bm_ext) {
1149                         const unsigned long rs_flags = mdev->resync->flags;
1150                         if (rs_flags & LC_STARVING)
1151                                 dev_warn(DEV, "Have to wait for element"
1152                                      " (resync LRU too small?)\n");
1153                         BUG_ON(rs_flags & LC_LOCKED);
1154                         goto try_again;
1155                 }
1156                 if (bm_ext->lce.lc_number != enr) {
1157                         bm_ext->rs_left = drbd_bm_e_weight(mdev, enr);
1158                         bm_ext->rs_failed = 0;
1159                         lc_committed(mdev->resync);
1160                         wake_up(&mdev->al_wait);
1161                         D_ASSERT(test_bit(BME_LOCKED, &bm_ext->flags) == 0);
1162                 }
1163                 set_bit(BME_NO_WRITES, &bm_ext->flags);
1164                 D_ASSERT(bm_ext->lce.refcnt == 1);
1165                 mdev->resync_locked++;
1166                 goto check_al;
1167         }
1168 check_al:
1169         for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
1170                 if (lc_is_used(mdev->act_log, al_enr+i))
1171                         goto try_again;
1172         }
1173         set_bit(BME_LOCKED, &bm_ext->flags);
1174 proceed:
1175         mdev->resync_wenr = LC_FREE;
1176         spin_unlock_irq(&mdev->al_lock);
1177         return 0;
1178
1179 try_again:
1180         if (bm_ext)
1181                 mdev->resync_wenr = enr;
1182         spin_unlock_irq(&mdev->al_lock);
1183         return -EAGAIN;
1184 }
1185
1186 void drbd_rs_complete_io(struct drbd_conf *mdev, sector_t sector)
1187 {
1188         unsigned int enr = BM_SECT_TO_EXT(sector);
1189         struct lc_element *e;
1190         struct bm_extent *bm_ext;
1191         unsigned long flags;
1192
1193         spin_lock_irqsave(&mdev->al_lock, flags);
1194         e = lc_find(mdev->resync, enr);
1195         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1196         if (!bm_ext) {
1197                 spin_unlock_irqrestore(&mdev->al_lock, flags);
1198                 if (__ratelimit(&drbd_ratelimit_state))
1199                         dev_err(DEV, "drbd_rs_complete_io() called, but extent not found\n");
1200                 return;
1201         }
1202
1203         if (bm_ext->lce.refcnt == 0) {
1204                 spin_unlock_irqrestore(&mdev->al_lock, flags);
1205                 dev_err(DEV, "drbd_rs_complete_io(,%llu [=%u]) called, "
1206                     "but refcnt is 0!?\n",
1207                     (unsigned long long)sector, enr);
1208                 return;
1209         }
1210
1211         if (lc_put(mdev->resync, &bm_ext->lce) == 0) {
1212                 bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */
1213                 mdev->resync_locked--;
1214                 wake_up(&mdev->al_wait);
1215         }
1216
1217         spin_unlock_irqrestore(&mdev->al_lock, flags);
1218 }
1219
1220 /**
1221  * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
1222  * @mdev:       DRBD device.
1223  */
1224 void drbd_rs_cancel_all(struct drbd_conf *mdev)
1225 {
1226         spin_lock_irq(&mdev->al_lock);
1227
1228         if (get_ldev_if_state(mdev, D_FAILED)) { /* Makes sure ->resync is there. */
1229                 lc_reset(mdev->resync);
1230                 put_ldev(mdev);
1231         }
1232         mdev->resync_locked = 0;
1233         mdev->resync_wenr = LC_FREE;
1234         spin_unlock_irq(&mdev->al_lock);
1235         wake_up(&mdev->al_wait);
1236 }
1237
1238 /**
1239  * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
1240  * @mdev:       DRBD device.
1241  *
1242  * Returns 0 upon success, -EAGAIN if at least one reference count was
1243  * not zero.
1244  */
1245 int drbd_rs_del_all(struct drbd_conf *mdev)
1246 {
1247         struct lc_element *e;
1248         struct bm_extent *bm_ext;
1249         int i;
1250
1251         spin_lock_irq(&mdev->al_lock);
1252
1253         if (get_ldev_if_state(mdev, D_FAILED)) {
1254                 /* ok, ->resync is there. */
1255                 for (i = 0; i < mdev->resync->nr_elements; i++) {
1256                         e = lc_element_by_index(mdev->resync, i);
1257                         bm_ext = lc_entry(e, struct bm_extent, lce);
1258                         if (bm_ext->lce.lc_number == LC_FREE)
1259                                 continue;
1260                         if (bm_ext->lce.lc_number == mdev->resync_wenr) {
1261                                 dev_info(DEV, "dropping %u in drbd_rs_del_all, apparently"
1262                                      " got 'synced' by application io\n",
1263                                      mdev->resync_wenr);
1264                                 D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
1265                                 D_ASSERT(test_bit(BME_NO_WRITES, &bm_ext->flags));
1266                                 clear_bit(BME_NO_WRITES, &bm_ext->flags);
1267                                 mdev->resync_wenr = LC_FREE;
1268                                 lc_put(mdev->resync, &bm_ext->lce);
1269                         }
1270                         if (bm_ext->lce.refcnt != 0) {
1271                                 dev_info(DEV, "Retrying drbd_rs_del_all() later. "
1272                                      "refcnt=%d\n", bm_ext->lce.refcnt);
1273                                 put_ldev(mdev);
1274                                 spin_unlock_irq(&mdev->al_lock);
1275                                 return -EAGAIN;
1276                         }
1277                         D_ASSERT(!test_bit(BME_LOCKED, &bm_ext->flags));
1278                         D_ASSERT(!test_bit(BME_NO_WRITES, &bm_ext->flags));
1279                         lc_del(mdev->resync, &bm_ext->lce);
1280                 }
1281                 D_ASSERT(mdev->resync->used == 0);
1282                 put_ldev(mdev);
1283         }
1284         spin_unlock_irq(&mdev->al_lock);
1285
1286         return 0;
1287 }
1288
1289 /**
1290  * drbd_rs_failed_io() - Record information on a failure to resync the specified blocks
1291  * @mdev:       DRBD device.
1292  * @sector:     The sector number.
1293  * @size:       Size of failed IO operation, in byte.
1294  */
1295 void drbd_rs_failed_io(struct drbd_conf *mdev, sector_t sector, int size)
1296 {
1297         /* Is called from worker and receiver context _only_ */
1298         unsigned long sbnr, ebnr, lbnr;
1299         unsigned long count;
1300         sector_t esector, nr_sectors;
1301         int wake_up = 0;
1302
1303         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
1304                 dev_err(DEV, "drbd_rs_failed_io: sector=%llus size=%d nonsense!\n",
1305                                 (unsigned long long)sector, size);
1306                 return;
1307         }
1308         nr_sectors = drbd_get_capacity(mdev->this_bdev);
1309         esector = sector + (size >> 9) - 1;
1310
1311         if (!expect(sector < nr_sectors))
1312                 return;
1313         if (!expect(esector < nr_sectors))
1314                 esector = nr_sectors - 1;
1315
1316         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
1317
1318         /*
1319          * round up start sector, round down end sector.  we make sure we only
1320          * handle full, aligned, BM_BLOCK_SIZE (4K) blocks */
1321         if (unlikely(esector < BM_SECT_PER_BIT-1))
1322                 return;
1323         if (unlikely(esector == (nr_sectors-1)))
1324                 ebnr = lbnr;
1325         else
1326                 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
1327         sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
1328
1329         if (sbnr > ebnr)
1330                 return;
1331
1332         /*
1333          * ok, (capacity & 7) != 0 sometimes, but who cares...
1334          * we count rs_{total,left} in bits, not sectors.
1335          */
1336         spin_lock_irq(&mdev->al_lock);
1337         count = drbd_bm_count_bits(mdev, sbnr, ebnr);
1338         if (count) {
1339                 mdev->rs_failed += count;
1340
1341                 if (get_ldev(mdev)) {
1342                         drbd_try_clear_on_disk_bm(mdev, sector, count, false);
1343                         put_ldev(mdev);
1344                 }
1345
1346                 /* just wake_up unconditional now, various lc_chaged(),
1347                  * lc_put() in drbd_try_clear_on_disk_bm(). */
1348                 wake_up = 1;
1349         }
1350         spin_unlock_irq(&mdev->al_lock);
1351         if (wake_up)
1352                 wake_up(&mdev->al_wait);
1353 }