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
  33
  34 enum al_transaction_types {
  35         AL_TR_UPDATE = 0,
  36         AL_TR_INITIALIZED = 0xffff
  37 };
  38 /* all fields on disc in big endian */
  39 struct __packed al_transaction_on_disk {
  40         /* don't we all like magic */
  41         __be32  magic;
  42
  43         /* to identify the most recent transaction block
  44          * in the on disk ring buffer */
  45         __be32  tr_number;
  46
  47         /* checksum on the full 4k block, with this field set to 0. */
  48         __be32  crc32c;
  49
  50         /* type of transaction, special transaction types like:
  51          * purge-all, set-all-idle, set-all-active, ... to-be-defined
  52          * see also enum al_transaction_types */
  53         __be16  transaction_type;
  54
  55         /* we currently allow only a few thousand extents,
  56          * so 16bit will be enough for the slot number. */
  57
  58         /* how many updates in this transaction */
  59         __be16  n_updates;
  60
  61         /* maximum slot number, "al-extents" in drbd.conf speak.
  62          * Having this in each transaction should make reconfiguration
  63          * of that parameter easier. */
  64         __be16  context_size;
  65
  66         /* slot number the context starts with */
  67         __be16  context_start_slot_nr;
  68
  69         /* Some reserved bytes.  Expected usage is a 64bit counter of
  70          * sectors-written since device creation, and other data generation tag
  71          * supporting usage */
  72         __be32  __reserved[4];
  73
  74         /* --- 36 byte used --- */
  75
  76         /* Reserve space for up to AL_UPDATES_PER_TRANSACTION changes
  77          * in one transaction, then use the remaining byte in the 4k block for
  78          * context information.  "Flexible" number of updates per transaction
  79          * does not help, as we have to account for the case when all update
  80          * slots are used anyways, so it would only complicate code without
  81          * additional benefit.
  82          */
  83         __be16  update_slot_nr[AL_UPDATES_PER_TRANSACTION];
  84
  85         /* but the extent number is 32bit, which at an extent size of 4 MiB
  86          * allows to cover device sizes of up to 2**54 Byte (16 PiB) */
  87         __be32  update_extent_nr[AL_UPDATES_PER_TRANSACTION];
  88
  89         /* --- 420 bytes used (36 + 64*6) --- */
  90
  91         /* 4096 - 420 = 3676 = 919 * 4 */
  92         __be32  context[AL_CONTEXT_PER_TRANSACTION];
  93 };
  94
  95 struct update_odbm_work {
  96         struct drbd_work w;
  97         struct drbd_device *device;
  98         unsigned int enr;
  99 };
 100
 101 struct update_al_work {
 102         struct drbd_work w;
 103         struct drbd_device *device;
 104         struct completion event;
 105         int err;
 106 };
 107
 108
 109 void *drbd_md_get_buffer(struct drbd_device *device)
 110 {
 111         int r;
 112
 113         wait_event(device->misc_wait,
 114                    (r = atomic_cmpxchg(&device->md_io_in_use, 0, 1)) == 0 ||
 115                    device->state.disk <= D_FAILED);
 116
 117         return r ? NULL : page_address(device->md_io_page);
 118 }
 119
 120 void drbd_md_put_buffer(struct drbd_device *device)
 121 {
 122         if (atomic_dec_and_test(&device->md_io_in_use))
 123                 wake_up(&device->misc_wait);
 124 }
 125
 126 void wait_until_done_or_force_detached(struct drbd_device *device, struct drbd_backing_dev *bdev,
 127                                      unsigned int *done)
 128 {
 129         long dt;
 130
 131         rcu_read_lock();
 132         dt = rcu_dereference(bdev->disk_conf)->disk_timeout;
 133         rcu_read_unlock();
 134         dt = dt * HZ / 10;
 135         if (dt == 0)
 136                 dt = MAX_SCHEDULE_TIMEOUT;
 137
 138         dt = wait_event_timeout(device->misc_wait,
 139                         *done || test_bit(FORCE_DETACH, &device->flags), dt);
 140         if (dt == 0) {
 141                 drbd_err(device, "meta-data IO operation timed out\n");
 142                 drbd_chk_io_error(device, 1, DRBD_FORCE_DETACH);
 143         }
 144 }
 145
 146 static int _drbd_md_sync_page_io(struct drbd_device *device,
 147                                  struct drbd_backing_dev *bdev,
 148                                  struct page *page, sector_t sector,
 149                                  int rw, int size)
 150 {
 151         struct bio *bio;
 152         int err;
 153
 154         device->md_io.done = 0;
 155         device->md_io.error = -ENODEV;
 156
 157         if ((rw & WRITE) && !test_bit(MD_NO_FUA, &device->flags))
 158                 rw |= REQ_FUA | REQ_FLUSH;
 159         rw |= REQ_SYNC;
 160
 161         bio = bio_alloc_drbd(GFP_NOIO);
 162         bio->bi_bdev = bdev->md_bdev;
 163         bio->bi_iter.bi_sector = sector;
 164         err = -EIO;
 165         if (bio_add_page(bio, page, size, 0) != size)
 166                 goto out;
 167         bio->bi_private = &device->md_io;
 168         bio->bi_end_io = drbd_md_io_complete;
 169         bio->bi_rw = rw;
 170
 171         if (!(rw & WRITE) && device->state.disk == D_DISKLESS && device->ldev == NULL)
 172                 /* special case, drbd_md_read() during drbd_adm_attach(): no get_ldev */
 173                 ;
 174         else if (!get_ldev_if_state(device, D_ATTACHING)) {
 175                 /* Corresponding put_ldev in drbd_md_io_complete() */
 176                 drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in _drbd_md_sync_page_io()\n");
 177                 err = -ENODEV;
 178                 goto out;
 179         }
 180
 181         bio_get(bio); /* one bio_put() is in the completion handler */
 182         atomic_inc(&device->md_io_in_use); /* drbd_md_put_buffer() is in the completion handler */
 183         if (drbd_insert_fault(device, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
 184                 bio_endio(bio, -EIO);
 185         else
 186                 submit_bio(rw, bio);
 187         wait_until_done_or_force_detached(device, bdev, &device->md_io.done);
 188         if (bio_flagged(bio, BIO_UPTODATE))
 189                 err = device->md_io.error;
 190
 191  out:
 192         bio_put(bio);
 193         return err;
 194 }
 195
 196 int drbd_md_sync_page_io(struct drbd_device *device, struct drbd_backing_dev *bdev,
 197                          sector_t sector, int rw)
 198 {
 199         int err;
 200         struct page *iop = device->md_io_page;
 201
 202         D_ASSERT(device, atomic_read(&device->md_io_in_use) == 1);
 203
 204         BUG_ON(!bdev->md_bdev);
 205
 206         dynamic_drbd_dbg(device, "meta_data io: %s [%d]:%s(,%llus,%s) %pS\n",
 207              current->comm, current->pid, __func__,
 208              (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ",
 209              (void*)_RET_IP_ );
 210
 211         if (sector < drbd_md_first_sector(bdev) ||
 212             sector + 7 > drbd_md_last_sector(bdev))
 213                 drbd_alert(device, "%s [%d]:%s(,%llus,%s) out of range md access!\n",
 214                      current->comm, current->pid, __func__,
 215                      (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
 216
 217         /* we do all our meta data IO in aligned 4k blocks. */
 218         err = _drbd_md_sync_page_io(device, bdev, iop, sector, rw, 4096);
 219         if (err) {
 220                 drbd_err(device, "drbd_md_sync_page_io(,%llus,%s) failed with error %d\n",
 221                     (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ", err);
 222         }
 223         return err;
 224 }
 225
 226 static struct bm_extent *find_active_resync_extent(struct drbd_device *device, unsigned int enr)
 227 {
 228         struct lc_element *tmp;
 229         tmp = lc_find(device->resync, enr/AL_EXT_PER_BM_SECT);
 230         if (unlikely(tmp != NULL)) {
 231                 struct bm_extent  *bm_ext = lc_entry(tmp, struct bm_extent, lce);
 232                 if (test_bit(BME_NO_WRITES, &bm_ext->flags))
 233                         return bm_ext;
 234         }
 235         return NULL;
 236 }
 237
 238 static struct lc_element *_al_get(struct drbd_device *device, unsigned int enr, bool nonblock)
 239 {
 240         struct lc_element *al_ext;
 241         struct bm_extent *bm_ext;
 242         int wake;
 243
 244         spin_lock_irq(&device->al_lock);
 245         bm_ext = find_active_resync_extent(device, enr);
 246         if (bm_ext) {
 247                 wake = !test_and_set_bit(BME_PRIORITY, &bm_ext->flags);
 248                 spin_unlock_irq(&device->al_lock);
 249                 if (wake)
 250                         wake_up(&device->al_wait);
 251                 return NULL;
 252         }
 253         if (nonblock)
 254                 al_ext = lc_try_get(device->act_log, enr);
 255         else
 256                 al_ext = lc_get(device->act_log, enr);
 257         spin_unlock_irq(&device->al_lock);
 258         return al_ext;
 259 }
 260
 261 bool drbd_al_begin_io_fastpath(struct drbd_device *device, struct drbd_interval *i)
 262 {
 263         /* for bios crossing activity log extent boundaries,
 264          * we may need to activate two extents in one go */
 265         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 266         unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 267
 268         D_ASSERT(device, (unsigned)(last - first) <= 1);
 269         D_ASSERT(device, atomic_read(&device->local_cnt) > 0);
 270
 271         /* FIXME figure out a fast path for bios crossing AL extent boundaries */
 272         if (first != last)
 273                 return false;
 274
 275         return _al_get(device, first, true);
 276 }
 277
 278 bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *i)
 279 {
 280         /* for bios crossing activity log extent boundaries,
 281          * we may need to activate two extents in one go */
 282         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 283         unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 284         unsigned enr;
 285         bool need_transaction = false;
 286
 287         D_ASSERT(device, first <= last);
 288         D_ASSERT(device, atomic_read(&device->local_cnt) > 0);
 289
 290         for (enr = first; enr <= last; enr++) {
 291                 struct lc_element *al_ext;
 292                 wait_event(device->al_wait,
 293                                 (al_ext = _al_get(device, enr, false)) != NULL);
 294                 if (al_ext->lc_number != enr)
 295                         need_transaction = true;
 296         }
 297         return need_transaction;
 298 }
 299
 300 static int al_write_transaction(struct drbd_device *device, bool delegate);
 301
 302 /* When called through generic_make_request(), we must delegate
 303  * activity log I/O to the worker thread: a further request
 304  * submitted via generic_make_request() within the same task
 305  * would be queued on current->bio_list, and would only start
 306  * after this function returns (see generic_make_request()).
 307  *
 308  * However, if we *are* the worker, we must not delegate to ourselves.
 309  */
 310
 311 /*
 312  * @delegate:   delegate activity log I/O to the worker thread
 313  */
 314 void drbd_al_begin_io_commit(struct drbd_device *device, bool delegate)
 315 {
 316         bool locked = false;
 317
 318         BUG_ON(delegate && current == first_peer_device(device)->connection->worker.task);
 319
 320         /* Serialize multiple transactions.
 321          * This uses test_and_set_bit, memory barrier is implicit.
 322          */
 323         wait_event(device->al_wait,
 324                         device->act_log->pending_changes == 0 ||
 325                         (locked = lc_try_lock_for_transaction(device->act_log)));
 326
 327         if (locked) {
 328                 /* Double check: it may have been committed by someone else,
 329                  * while we have been waiting for the lock. */
 330                 if (device->act_log->pending_changes) {
 331                         bool write_al_updates;
 332
 333                         rcu_read_lock();
 334                         write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
 335                         rcu_read_unlock();
 336
 337                         if (write_al_updates)
 338                                 al_write_transaction(device, delegate);
 339                         spin_lock_irq(&device->al_lock);
 340                         /* FIXME
 341                         if (err)
 342                                 we need an "lc_cancel" here;
 343                         */
 344                         lc_committed(device->act_log);
 345                         spin_unlock_irq(&device->al_lock);
 346                 }
 347                 lc_unlock(device->act_log);
 348                 wake_up(&device->al_wait);
 349         }
 350 }
 351
 352 /*
 353  * @delegate:   delegate activity log I/O to the worker thread
 354  */
 355 void drbd_al_begin_io(struct drbd_device *device, struct drbd_interval *i, bool delegate)
 356 {
 357         BUG_ON(delegate && current == first_peer_device(device)->connection->worker.task);
 358
 359         if (drbd_al_begin_io_prepare(device, i))
 360                 drbd_al_begin_io_commit(device, delegate);
 361 }
 362
 363 int drbd_al_begin_io_nonblock(struct drbd_device *device, struct drbd_interval *i)
 364 {
 365         struct lru_cache *al = device->act_log;
 366         /* for bios crossing activity log extent boundaries,
 367          * we may need to activate two extents in one go */
 368         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 369         unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 370         unsigned nr_al_extents;
 371         unsigned available_update_slots;
 372         unsigned enr;
 373
 374         D_ASSERT(device, first <= last);
 375
 376         nr_al_extents = 1 + last - first; /* worst case: all touched extends are cold. */
 377         available_update_slots = min(al->nr_elements - al->used,
 378                                 al->max_pending_changes - al->pending_changes);
 379
 380         /* We want all necessary updates for a given request within the same transaction
 381          * We could first check how many updates are *actually* needed,
 382          * and use that instead of the worst-case nr_al_extents */
 383         if (available_update_slots < nr_al_extents)
 384                 return -EWOULDBLOCK;
 385
 386         /* Is resync active in this area? */
 387         for (enr = first; enr <= last; enr++) {
 388                 struct lc_element *tmp;
 389                 tmp = lc_find(device->resync, enr/AL_EXT_PER_BM_SECT);
 390                 if (unlikely(tmp != NULL)) {
 391                         struct bm_extent  *bm_ext = lc_entry(tmp, struct bm_extent, lce);
 392                         if (test_bit(BME_NO_WRITES, &bm_ext->flags)) {
 393                                 if (!test_and_set_bit(BME_PRIORITY, &bm_ext->flags))
 394                                         return -EBUSY;
 395                                 return -EWOULDBLOCK;
 396                         }
 397                 }
 398         }
 399
 400         /* Checkout the refcounts.
 401          * Given that we checked for available elements and update slots above,
 402          * this has to be successful. */
 403         for (enr = first; enr <= last; enr++) {
 404                 struct lc_element *al_ext;
 405                 al_ext = lc_get_cumulative(device->act_log, enr);
 406                 if (!al_ext)
 407                         drbd_info(device, "LOGIC BUG for enr=%u\n", enr);
 408         }
 409         return 0;
 410 }
 411
 412 void drbd_al_complete_io(struct drbd_device *device, struct drbd_interval *i)
 413 {
 414         /* for bios crossing activity log extent boundaries,
 415          * we may need to activate two extents in one go */
 416         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 417         unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 418         unsigned enr;
 419         struct lc_element *extent;
 420         unsigned long flags;
 421
 422         D_ASSERT(device, first <= last);
 423         spin_lock_irqsave(&device->al_lock, flags);
 424
 425         for (enr = first; enr <= last; enr++) {
 426                 extent = lc_find(device->act_log, enr);
 427                 if (!extent) {
 428                         drbd_err(device, "al_complete_io() called on inactive extent %u\n", enr);
 429                         continue;
 430                 }
 431                 lc_put(device->act_log, extent);
 432         }
 433         spin_unlock_irqrestore(&device->al_lock, flags);
 434         wake_up(&device->al_wait);
 435 }
 436
 437 #if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
 438 /* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
 439  * are still coupled, or assume too much about their relation.
 440  * Code below will not work if this is violated.
 441  * Will be cleaned up with some followup patch.
 442  */
 443 # error FIXME
 444 #endif
 445
 446 static unsigned int al_extent_to_bm_page(unsigned int al_enr)
 447 {
 448         return al_enr >>
 449                 /* bit to page */
 450                 ((PAGE_SHIFT + 3) -
 451                 /* al extent number to bit */
 452                  (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
 453 }
 454
 455 static unsigned int rs_extent_to_bm_page(unsigned int rs_enr)
 456 {
 457         return rs_enr >>
 458                 /* bit to page */
 459                 ((PAGE_SHIFT + 3) -
 460                 /* resync extent number to bit */
 461                  (BM_EXT_SHIFT - BM_BLOCK_SHIFT));
 462 }
 463
 464 static sector_t al_tr_number_to_on_disk_sector(struct drbd_device *device)
 465 {
 466         const unsigned int stripes = device->ldev->md.al_stripes;
 467         const unsigned int stripe_size_4kB = device->ldev->md.al_stripe_size_4k;
 468
 469         /* transaction number, modulo on-disk ring buffer wrap around */
 470         unsigned int t = device->al_tr_number % (device->ldev->md.al_size_4k);
 471
 472         /* ... to aligned 4k on disk block */
 473         t = ((t % stripes) * stripe_size_4kB) + t/stripes;
 474
 475         /* ... to 512 byte sector in activity log */
 476         t *= 8;
 477
 478         /* ... plus offset to the on disk position */
 479         return device->ldev->md.md_offset + device->ldev->md.al_offset + t;
 480 }
 481
 482 static int
 483 _al_write_transaction(struct drbd_device *device)
 484 {
 485         struct al_transaction_on_disk *buffer;
 486         struct lc_element *e;
 487         sector_t sector;
 488         int i, mx;
 489         unsigned extent_nr;
 490         unsigned crc = 0;
 491         int err = 0;
 492
 493         if (!get_ldev(device)) {
 494                 drbd_err(device, "disk is %s, cannot start al transaction\n",
 495                         drbd_disk_str(device->state.disk));
 496                 return -EIO;
 497         }
 498
 499         /* The bitmap write may have failed, causing a state change. */
 500         if (device->state.disk < D_INCONSISTENT) {
 501                 drbd_err(device,
 502                         "disk is %s, cannot write al transaction\n",
 503                         drbd_disk_str(device->state.disk));
 504                 put_ldev(device);
 505                 return -EIO;
 506         }
 507
 508         buffer = drbd_md_get_buffer(device); /* protects md_io_buffer, al_tr_cycle, ... */
 509         if (!buffer) {
 510                 drbd_err(device, "disk failed while waiting for md_io buffer\n");
 511                 put_ldev(device);
 512                 return -ENODEV;
 513         }
 514
 515         memset(buffer, 0, sizeof(*buffer));
 516         buffer->magic = cpu_to_be32(DRBD_AL_MAGIC);
 517         buffer->tr_number = cpu_to_be32(device->al_tr_number);
 518
 519         i = 0;
 520
 521         /* Even though no one can start to change this list
 522          * once we set the LC_LOCKED -- from drbd_al_begin_io(),
 523          * lc_try_lock_for_transaction() --, someone may still
 524          * be in the process of changing it. */
 525         spin_lock_irq(&device->al_lock);
 526         list_for_each_entry(e, &device->act_log->to_be_changed, list) {
 527                 if (i == AL_UPDATES_PER_TRANSACTION) {
 528                         i++;
 529                         break;
 530                 }
 531                 buffer->update_slot_nr[i] = cpu_to_be16(e->lc_index);
 532                 buffer->update_extent_nr[i] = cpu_to_be32(e->lc_new_number);
 533                 if (e->lc_number != LC_FREE)
 534                         drbd_bm_mark_for_writeout(device,
 535                                         al_extent_to_bm_page(e->lc_number));
 536                 i++;
 537         }
 538         spin_unlock_irq(&device->al_lock);
 539         BUG_ON(i > AL_UPDATES_PER_TRANSACTION);
 540
 541         buffer->n_updates = cpu_to_be16(i);
 542         for ( ; i < AL_UPDATES_PER_TRANSACTION; i++) {
 543                 buffer->update_slot_nr[i] = cpu_to_be16(-1);
 544                 buffer->update_extent_nr[i] = cpu_to_be32(LC_FREE);
 545         }
 546
 547         buffer->context_size = cpu_to_be16(device->act_log->nr_elements);
 548         buffer->context_start_slot_nr = cpu_to_be16(device->al_tr_cycle);
 549
 550         mx = min_t(int, AL_CONTEXT_PER_TRANSACTION,
 551                    device->act_log->nr_elements - device->al_tr_cycle);
 552         for (i = 0; i < mx; i++) {
 553                 unsigned idx = device->al_tr_cycle + i;
 554                 extent_nr = lc_element_by_index(device->act_log, idx)->lc_number;
 555                 buffer->context[i] = cpu_to_be32(extent_nr);
 556         }
 557         for (; i < AL_CONTEXT_PER_TRANSACTION; i++)
 558                 buffer->context[i] = cpu_to_be32(LC_FREE);
 559
 560         device->al_tr_cycle += AL_CONTEXT_PER_TRANSACTION;
 561         if (device->al_tr_cycle >= device->act_log->nr_elements)
 562                 device->al_tr_cycle = 0;
 563
 564         sector = al_tr_number_to_on_disk_sector(device);
 565
 566         crc = crc32c(0, buffer, 4096);
 567         buffer->crc32c = cpu_to_be32(crc);
 568
 569         if (drbd_bm_write_hinted(device))
 570                 err = -EIO;
 571         else {
 572                 bool write_al_updates;
 573                 rcu_read_lock();
 574                 write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
 575                 rcu_read_unlock();
 576                 if (write_al_updates) {
 577                         if (drbd_md_sync_page_io(device, device->ldev, sector, WRITE)) {
 578                                 err = -EIO;
 579                                 drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR);
 580                         } else {
 581                                 device->al_tr_number++;
 582                                 device->al_writ_cnt++;
 583                         }
 584                 }
 585         }
 586
 587         drbd_md_put_buffer(device);
 588         put_ldev(device);
 589
 590         return err;
 591 }
 592
 593
 594 static int w_al_write_transaction(struct drbd_work *w, int unused)
 595 {
 596         struct update_al_work *aw = container_of(w, struct update_al_work, w);
 597         struct drbd_device *device = aw->device;
 598         int err;
 599
 600         err = _al_write_transaction(device);
 601         aw->err = err;
 602         complete(&aw->event);
 603
 604         return err != -EIO ? err : 0;
 605 }
 606
 607 /* Calls from worker context (see w_restart_disk_io()) need to write the
 608    transaction directly. Others came through generic_make_request(),
 609    those need to delegate it to the worker. */
 610 static int al_write_transaction(struct drbd_device *device, bool delegate)
 611 {
 612         if (delegate) {
 613                 struct update_al_work al_work;
 614                 init_completion(&al_work.event);
 615                 al_work.w.cb = w_al_write_transaction;
 616                 al_work.device = device;
 617                 drbd_queue_work_front(&first_peer_device(device)->connection->sender_work,
 618                                       &al_work.w);
 619                 wait_for_completion(&al_work.event);
 620                 return al_work.err;
 621         } else
 622                 return _al_write_transaction(device);
 623 }
 624
 625 static int _try_lc_del(struct drbd_device *device, struct lc_element *al_ext)
 626 {
 627         int rv;
 628
 629         spin_lock_irq(&device->al_lock);
 630         rv = (al_ext->refcnt == 0);
 631         if (likely(rv))
 632                 lc_del(device->act_log, al_ext);
 633         spin_unlock_irq(&device->al_lock);
 634
 635         return rv;
 636 }
 637
 638 /**
 639  * drbd_al_shrink() - Removes all active extents form the activity log
 640  * @device:     DRBD device.
 641  *
 642  * Removes all active extents form the activity log, waiting until
 643  * the reference count of each entry dropped to 0 first, of course.
 644  *
 645  * You need to lock device->act_log with lc_try_lock() / lc_unlock()
 646  */
 647 void drbd_al_shrink(struct drbd_device *device)
 648 {
 649         struct lc_element *al_ext;
 650         int i;
 651
 652         D_ASSERT(device, test_bit(__LC_LOCKED, &device->act_log->flags));
 653
 654         for (i = 0; i < device->act_log->nr_elements; i++) {
 655                 al_ext = lc_element_by_index(device->act_log, i);
 656                 if (al_ext->lc_number == LC_FREE)
 657                         continue;
 658                 wait_event(device->al_wait, _try_lc_del(device, al_ext));
 659         }
 660
 661         wake_up(&device->al_wait);
 662 }
 663
 664 int drbd_initialize_al(struct drbd_device *device, void *buffer)
 665 {
 666         struct al_transaction_on_disk *al = buffer;
 667         struct drbd_md *md = &device->ldev->md;
 668         sector_t al_base = md->md_offset + md->al_offset;
 669         int al_size_4k = md->al_stripes * md->al_stripe_size_4k;
 670         int i;
 671
 672         memset(al, 0, 4096);
 673         al->magic = cpu_to_be32(DRBD_AL_MAGIC);
 674         al->transaction_type = cpu_to_be16(AL_TR_INITIALIZED);
 675         al->crc32c = cpu_to_be32(crc32c(0, al, 4096));
 676
 677         for (i = 0; i < al_size_4k; i++) {
 678                 int err = drbd_md_sync_page_io(device, device->ldev, al_base + i * 8, WRITE);
 679                 if (err)
 680                         return err;
 681         }
 682         return 0;
 683 }
 684
 685 static int w_update_odbm(struct drbd_work *w, int unused)
 686 {
 687         struct update_odbm_work *udw = container_of(w, struct update_odbm_work, w);
 688         struct drbd_device *device = udw->device;
 689         struct sib_info sib = { .sib_reason = SIB_SYNC_PROGRESS, };
 690
 691         if (!get_ldev(device)) {
 692                 if (__ratelimit(&drbd_ratelimit_state))
 693                         drbd_warn(device, "Can not update on disk bitmap, local IO disabled.\n");
 694                 kfree(udw);
 695                 return 0;
 696         }
 697
 698         drbd_bm_write_page(device, rs_extent_to_bm_page(udw->enr));
 699         put_ldev(device);
 700
 701         kfree(udw);
 702
 703         if (drbd_bm_total_weight(device) <= device->rs_failed) {
 704                 switch (device->state.conn) {
 705                 case C_SYNC_SOURCE:  case C_SYNC_TARGET:
 706                 case C_PAUSED_SYNC_S: case C_PAUSED_SYNC_T:
 707                         drbd_resync_finished(device);
 708                 default:
 709                         /* nothing to do */
 710                         break;
 711                 }
 712         }
 713         drbd_bcast_event(device, &sib);
 714
 715         return 0;
 716 }
 717
 718
 719 /* ATTENTION. The AL's extents are 4MB each, while the extents in the
 720  * resync LRU-cache are 16MB each.
 721  * The caller of this function has to hold an get_ldev() reference.
 722  *
 723  * TODO will be obsoleted once we have a caching lru of the on disk bitmap
 724  */
 725 static void drbd_try_clear_on_disk_bm(struct drbd_device *device, sector_t sector,
 726                                       int count, int success)
 727 {
 728         struct lc_element *e;
 729         struct update_odbm_work *udw;
 730
 731         unsigned int enr;
 732
 733         D_ASSERT(device, atomic_read(&device->local_cnt));
 734
 735         /* I simply assume that a sector/size pair never crosses
 736          * a 16 MB extent border. (Currently this is true...) */
 737         enr = BM_SECT_TO_EXT(sector);
 738
 739         e = lc_get(device->resync, enr);
 740         if (e) {
 741                 struct bm_extent *ext = lc_entry(e, struct bm_extent, lce);
 742                 if (ext->lce.lc_number == enr) {
 743                         if (success)
 744                                 ext->rs_left -= count;
 745                         else
 746                                 ext->rs_failed += count;
 747                         if (ext->rs_left < ext->rs_failed) {
 748                                 drbd_warn(device, "BAD! sector=%llus enr=%u rs_left=%d "
 749                                     "rs_failed=%d count=%d cstate=%s\n",
 750                                      (unsigned long long)sector,
 751                                      ext->lce.lc_number, ext->rs_left,
 752                                      ext->rs_failed, count,
 753                                      drbd_conn_str(device->state.conn));
 754
 755                                 /* We don't expect to be able to clear more bits
 756                                  * than have been set when we originally counted
 757                                  * the set bits to cache that value in ext->rs_left.
 758                                  * Whatever the reason (disconnect during resync,
 759                                  * delayed local completion of an application write),
 760                                  * try to fix it up by recounting here. */
 761                                 ext->rs_left = drbd_bm_e_weight(device, enr);
 762                         }
 763                 } else {
 764                         /* Normally this element should be in the cache,
 765                          * since drbd_rs_begin_io() pulled it already in.
 766                          *
 767                          * But maybe an application write finished, and we set
 768                          * something outside the resync lru_cache in sync.
 769                          */
 770                         int rs_left = drbd_bm_e_weight(device, enr);
 771                         if (ext->flags != 0) {
 772                                 drbd_warn(device, "changing resync lce: %d[%u;%02lx]"
 773                                      " -> %d[%u;00]\n",
 774                                      ext->lce.lc_number, ext->rs_left,
 775                                      ext->flags, enr, rs_left);
 776                                 ext->flags = 0;
 777                         }
 778                         if (ext->rs_failed) {
 779                                 drbd_warn(device, "Kicking resync_lru element enr=%u "
 780                                      "out with rs_failed=%d\n",
 781                                      ext->lce.lc_number, ext->rs_failed);
 782                         }
 783                         ext->rs_left = rs_left;
 784                         ext->rs_failed = success ? 0 : count;
 785                         /* we don't keep a persistent log of the resync lru,
 786                          * we can commit any change right away. */
 787                         lc_committed(device->resync);
 788                 }
 789                 lc_put(device->resync, &ext->lce);
 790                 /* no race, we are within the al_lock! */
 791
 792                 if (ext->rs_left == ext->rs_failed) {
 793                         ext->rs_failed = 0;
 794
 795                         udw = kmalloc(sizeof(*udw), GFP_ATOMIC);
 796                         if (udw) {
 797                                 udw->enr = ext->lce.lc_number;
 798                                 udw->w.cb = w_update_odbm;
 799                                 udw->device = device;
 800                                 drbd_queue_work_front(&first_peer_device(device)->connection->sender_work,
 801                                                       &udw->w);
 802                         } else {
 803                                 drbd_warn(device, "Could not kmalloc an udw\n");
 804                         }
 805                 }
 806         } else {
 807                 drbd_err(device, "lc_get() failed! locked=%d/%d flags=%lu\n",
 808                     device->resync_locked,
 809                     device->resync->nr_elements,
 810                     device->resync->flags);
 811         }
 812 }
 813
 814 void drbd_advance_rs_marks(struct drbd_device *device, unsigned long still_to_go)
 815 {
 816         unsigned long now = jiffies;
 817         unsigned long last = device->rs_mark_time[device->rs_last_mark];
 818         int next = (device->rs_last_mark + 1) % DRBD_SYNC_MARKS;
 819         if (time_after_eq(now, last + DRBD_SYNC_MARK_STEP)) {
 820                 if (device->rs_mark_left[device->rs_last_mark] != still_to_go &&
 821                     device->state.conn != C_PAUSED_SYNC_T &&
 822                     device->state.conn != C_PAUSED_SYNC_S) {
 823                         device->rs_mark_time[next] = now;
 824                         device->rs_mark_left[next] = still_to_go;
 825                         device->rs_last_mark = next;
 826                 }
 827         }
 828 }
 829
 830 /* clear the bit corresponding to the piece of storage in question:
 831  * size byte of data starting from sector.  Only clear a bits of the affected
 832  * one ore more _aligned_ BM_BLOCK_SIZE blocks.
 833  *
 834  * called by worker on C_SYNC_TARGET and receiver on SyncSource.
 835  *
 836  */
 837 void __drbd_set_in_sync(struct drbd_device *device, sector_t sector, int size,
 838                        const char *file, const unsigned int line)
 839 {
 840         /* Is called from worker and receiver context _only_ */
 841         unsigned long sbnr, ebnr, lbnr;
 842         unsigned long count = 0;
 843         sector_t esector, nr_sectors;
 844         int wake_up = 0;
 845         unsigned long flags;
 846
 847         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_DISCARD_SIZE) {
 848                 drbd_err(device, "drbd_set_in_sync: sector=%llus size=%d nonsense!\n",
 849                                 (unsigned long long)sector, size);
 850                 return;
 851         }
 852
 853         if (!get_ldev(device))
 854                 return; /* no disk, no metadata, no bitmap to clear bits in */
 855
 856         nr_sectors = drbd_get_capacity(device->this_bdev);
 857         esector = sector + (size >> 9) - 1;
 858
 859         if (!expect(sector < nr_sectors))
 860                 goto out;
 861         if (!expect(esector < nr_sectors))
 862                 esector = nr_sectors - 1;
 863
 864         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
 865
 866         /* we clear it (in sync).
 867          * round up start sector, round down end sector.  we make sure we only
 868          * clear full, aligned, BM_BLOCK_SIZE (4K) blocks */
 869         if (unlikely(esector < BM_SECT_PER_BIT-1))
 870                 goto out;
 871         if (unlikely(esector == (nr_sectors-1)))
 872                 ebnr = lbnr;
 873         else
 874                 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
 875         sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
 876
 877         if (sbnr > ebnr)
 878                 goto out;
 879
 880         /*
 881          * ok, (capacity & 7) != 0 sometimes, but who cares...
 882          * we count rs_{total,left} in bits, not sectors.
 883          */
 884         count = drbd_bm_clear_bits(device, sbnr, ebnr);
 885         if (count) {
 886                 drbd_advance_rs_marks(device, drbd_bm_total_weight(device));
 887                 spin_lock_irqsave(&device->al_lock, flags);
 888                 drbd_try_clear_on_disk_bm(device, sector, count, true);
 889                 spin_unlock_irqrestore(&device->al_lock, flags);
 890
 891                 /* just wake_up unconditional now, various lc_chaged(),
 892                  * lc_put() in drbd_try_clear_on_disk_bm(). */
 893                 wake_up = 1;
 894         }
 895 out:
 896         put_ldev(device);
 897         if (wake_up)
 898                 wake_up(&device->al_wait);
 899 }
 900
 901 /*
 902  * this is intended to set one request worth of data out of sync.
 903  * affects at least 1 bit,
 904  * and at most 1+DRBD_MAX_BIO_SIZE/BM_BLOCK_SIZE bits.
 905  *
 906  * called by tl_clear and drbd_send_dblock (==drbd_make_request).
 907  * so this can be _any_ process.
 908  */
 909 int __drbd_set_out_of_sync(struct drbd_device *device, sector_t sector, int size,
 910                             const char *file, const unsigned int line)
 911 {
 912         unsigned long sbnr, ebnr, flags;
 913         sector_t esector, nr_sectors;
 914         unsigned int enr, count = 0;
 915         struct lc_element *e;
 916
 917         /* this should be an empty REQ_FLUSH */
 918         if (size == 0)
 919                 return 0;
 920
 921         if (size < 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_DISCARD_SIZE) {
 922                 drbd_err(device, "sector: %llus, size: %d\n",
 923                         (unsigned long long)sector, size);
 924                 return 0;
 925         }
 926
 927         if (!get_ldev(device))
 928                 return 0; /* no disk, no metadata, no bitmap to set bits in */
 929
 930         nr_sectors = drbd_get_capacity(device->this_bdev);
 931         esector = sector + (size >> 9) - 1;
 932
 933         if (!expect(sector < nr_sectors))
 934                 goto out;
 935         if (!expect(esector < nr_sectors))
 936                 esector = nr_sectors - 1;
 937
 938         /* we set it out of sync,
 939          * we do not need to round anything here */
 940         sbnr = BM_SECT_TO_BIT(sector);
 941         ebnr = BM_SECT_TO_BIT(esector);
 942
 943         /* ok, (capacity & 7) != 0 sometimes, but who cares...
 944          * we count rs_{total,left} in bits, not sectors.  */
 945         spin_lock_irqsave(&device->al_lock, flags);
 946         count = drbd_bm_set_bits(device, sbnr, ebnr);
 947
 948         enr = BM_SECT_TO_EXT(sector);
 949         e = lc_find(device->resync, enr);
 950         if (e)
 951                 lc_entry(e, struct bm_extent, lce)->rs_left += count;
 952         spin_unlock_irqrestore(&device->al_lock, flags);
 953
 954 out:
 955         put_ldev(device);
 956
 957         return count;
 958 }
 959
 960 static
 961 struct bm_extent *_bme_get(struct drbd_device *device, unsigned int enr)
 962 {
 963         struct lc_element *e;
 964         struct bm_extent *bm_ext;
 965         int wakeup = 0;
 966         unsigned long rs_flags;
 967
 968         spin_lock_irq(&device->al_lock);
 969         if (device->resync_locked > device->resync->nr_elements/2) {
 970                 spin_unlock_irq(&device->al_lock);
 971                 return NULL;
 972         }
 973         e = lc_get(device->resync, enr);
 974         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
 975         if (bm_ext) {
 976                 if (bm_ext->lce.lc_number != enr) {
 977                         bm_ext->rs_left = drbd_bm_e_weight(device, enr);
 978                         bm_ext->rs_failed = 0;
 979                         lc_committed(device->resync);
 980                         wakeup = 1;
 981                 }
 982                 if (bm_ext->lce.refcnt == 1)
 983                         device->resync_locked++;
 984                 set_bit(BME_NO_WRITES, &bm_ext->flags);
 985         }
 986         rs_flags = device->resync->flags;
 987         spin_unlock_irq(&device->al_lock);
 988         if (wakeup)
 989                 wake_up(&device->al_wait);
 990
 991         if (!bm_ext) {
 992                 if (rs_flags & LC_STARVING)
 993                         drbd_warn(device, "Have to wait for element"
 994                              " (resync LRU too small?)\n");
 995                 BUG_ON(rs_flags & LC_LOCKED);
 996         }
 997
 998         return bm_ext;
 999 }
1000
1001 static int _is_in_al(struct drbd_device *device, unsigned int enr)
1002 {
1003         int rv;
1004
1005         spin_lock_irq(&device->al_lock);
1006         rv = lc_is_used(device->act_log, enr);
1007         spin_unlock_irq(&device->al_lock);
1008
1009         return rv;
1010 }
1011
1012 /**
1013  * drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED
1014  * @device:     DRBD device.
1015  * @sector:     The sector number.
1016  *
1017  * This functions sleeps on al_wait. Returns 0 on success, -EINTR if interrupted.
1018  */
1019 int drbd_rs_begin_io(struct drbd_device *device, sector_t sector)
1020 {
1021         unsigned int enr = BM_SECT_TO_EXT(sector);
1022         struct bm_extent *bm_ext;
1023         int i, sig;
1024         bool sa;
1025
1026 retry:
1027         sig = wait_event_interruptible(device->al_wait,
1028                         (bm_ext = _bme_get(device, enr)));
1029         if (sig)
1030                 return -EINTR;
1031
1032         if (test_bit(BME_LOCKED, &bm_ext->flags))
1033                 return 0;
1034
1035         /* step aside only while we are above c-min-rate; unless disabled. */
1036         sa = drbd_rs_c_min_rate_throttle(device);
1037
1038         for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
1039                 sig = wait_event_interruptible(device->al_wait,
1040                                                !_is_in_al(device, enr * AL_EXT_PER_BM_SECT + i) ||
1041                                                (sa && test_bit(BME_PRIORITY, &bm_ext->flags)));
1042
1043                 if (sig || (sa && test_bit(BME_PRIORITY, &bm_ext->flags))) {
1044                         spin_lock_irq(&device->al_lock);
1045                         if (lc_put(device->resync, &bm_ext->lce) == 0) {
1046                                 bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */
1047                                 device->resync_locked--;
1048                                 wake_up(&device->al_wait);
1049                         }
1050                         spin_unlock_irq(&device->al_lock);
1051                         if (sig)
1052                                 return -EINTR;
1053                         if (schedule_timeout_interruptible(HZ/10))
1054                                 return -EINTR;
1055                         goto retry;
1056                 }
1057         }
1058         set_bit(BME_LOCKED, &bm_ext->flags);
1059         return 0;
1060 }
1061
1062 /**
1063  * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
1064  * @device:     DRBD device.
1065  * @sector:     The sector number.
1066  *
1067  * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
1068  * tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN
1069  * if there is still application IO going on in this area.
1070  */
1071 int drbd_try_rs_begin_io(struct drbd_device *device, sector_t sector)
1072 {
1073         unsigned int enr = BM_SECT_TO_EXT(sector);
1074         const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT;
1075         struct lc_element *e;
1076         struct bm_extent *bm_ext;
1077         int i;
1078
1079         spin_lock_irq(&device->al_lock);
1080         if (device->resync_wenr != LC_FREE && device->resync_wenr != enr) {
1081                 /* in case you have very heavy scattered io, it may
1082                  * stall the syncer undefined if we give up the ref count
1083                  * when we try again and requeue.
1084                  *
1085                  * if we don't give up the refcount, but the next time
1086                  * we are scheduled this extent has been "synced" by new
1087                  * application writes, we'd miss the lc_put on the
1088                  * extent we keep the refcount on.
1089                  * so we remembered which extent we had to try again, and
1090                  * if the next requested one is something else, we do
1091                  * the lc_put here...
1092                  * we also have to wake_up
1093                  */
1094                 e = lc_find(device->resync, device->resync_wenr);
1095                 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1096                 if (bm_ext) {
1097                         D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1098                         D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1099                         clear_bit(BME_NO_WRITES, &bm_ext->flags);
1100                         device->resync_wenr = LC_FREE;
1101                         if (lc_put(device->resync, &bm_ext->lce) == 0)
1102                                 device->resync_locked--;
1103                         wake_up(&device->al_wait);
1104                 } else {
1105                         drbd_alert(device, "LOGIC BUG\n");
1106                 }
1107         }
1108         /* TRY. */
1109         e = lc_try_get(device->resync, enr);
1110         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1111         if (bm_ext) {
1112                 if (test_bit(BME_LOCKED, &bm_ext->flags))
1113                         goto proceed;
1114                 if (!test_and_set_bit(BME_NO_WRITES, &bm_ext->flags)) {
1115                         device->resync_locked++;
1116                 } else {
1117                         /* we did set the BME_NO_WRITES,
1118                          * but then could not set BME_LOCKED,
1119                          * so we tried again.
1120                          * drop the extra reference. */
1121                         bm_ext->lce.refcnt--;
1122                         D_ASSERT(device, bm_ext->lce.refcnt > 0);
1123                 }
1124                 goto check_al;
1125         } else {
1126                 /* do we rather want to try later? */
1127                 if (device->resync_locked > device->resync->nr_elements-3)
1128                         goto try_again;
1129                 /* Do or do not. There is no try. -- Yoda */
1130                 e = lc_get(device->resync, enr);
1131                 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1132                 if (!bm_ext) {
1133                         const unsigned long rs_flags = device->resync->flags;
1134                         if (rs_flags & LC_STARVING)
1135                                 drbd_warn(device, "Have to wait for element"
1136                                      " (resync LRU too small?)\n");
1137                         BUG_ON(rs_flags & LC_LOCKED);
1138                         goto try_again;
1139                 }
1140                 if (bm_ext->lce.lc_number != enr) {
1141                         bm_ext->rs_left = drbd_bm_e_weight(device, enr);
1142                         bm_ext->rs_failed = 0;
1143                         lc_committed(device->resync);
1144                         wake_up(&device->al_wait);
1145                         D_ASSERT(device, test_bit(BME_LOCKED, &bm_ext->flags) == 0);
1146                 }
1147                 set_bit(BME_NO_WRITES, &bm_ext->flags);
1148                 D_ASSERT(device, bm_ext->lce.refcnt == 1);
1149                 device->resync_locked++;
1150                 goto check_al;
1151         }
1152 check_al:
1153         for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
1154                 if (lc_is_used(device->act_log, al_enr+i))
1155                         goto try_again;
1156         }
1157         set_bit(BME_LOCKED, &bm_ext->flags);
1158 proceed:
1159         device->resync_wenr = LC_FREE;
1160         spin_unlock_irq(&device->al_lock);
1161         return 0;
1162
1163 try_again:
1164         if (bm_ext)
1165                 device->resync_wenr = enr;
1166         spin_unlock_irq(&device->al_lock);
1167         return -EAGAIN;
1168 }
1169
1170 void drbd_rs_complete_io(struct drbd_device *device, sector_t sector)
1171 {
1172         unsigned int enr = BM_SECT_TO_EXT(sector);
1173         struct lc_element *e;
1174         struct bm_extent *bm_ext;
1175         unsigned long flags;
1176
1177         spin_lock_irqsave(&device->al_lock, flags);
1178         e = lc_find(device->resync, enr);
1179         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1180         if (!bm_ext) {
1181                 spin_unlock_irqrestore(&device->al_lock, flags);
1182                 if (__ratelimit(&drbd_ratelimit_state))
1183                         drbd_err(device, "drbd_rs_complete_io() called, but extent not found\n");
1184                 return;
1185         }
1186
1187         if (bm_ext->lce.refcnt == 0) {
1188                 spin_unlock_irqrestore(&device->al_lock, flags);
1189                 drbd_err(device, "drbd_rs_complete_io(,%llu [=%u]) called, "
1190                     "but refcnt is 0!?\n",
1191                     (unsigned long long)sector, enr);
1192                 return;
1193         }
1194
1195         if (lc_put(device->resync, &bm_ext->lce) == 0) {
1196                 bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */
1197                 device->resync_locked--;
1198                 wake_up(&device->al_wait);
1199         }
1200
1201         spin_unlock_irqrestore(&device->al_lock, flags);
1202 }
1203
1204 /**
1205  * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
1206  * @device:     DRBD device.
1207  */
1208 void drbd_rs_cancel_all(struct drbd_device *device)
1209 {
1210         spin_lock_irq(&device->al_lock);
1211
1212         if (get_ldev_if_state(device, D_FAILED)) { /* Makes sure ->resync is there. */
1213                 lc_reset(device->resync);
1214                 put_ldev(device);
1215         }
1216         device->resync_locked = 0;
1217         device->resync_wenr = LC_FREE;
1218         spin_unlock_irq(&device->al_lock);
1219         wake_up(&device->al_wait);
1220 }
1221
1222 /**
1223  * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
1224  * @device:     DRBD device.
1225  *
1226  * Returns 0 upon success, -EAGAIN if at least one reference count was
1227  * not zero.
1228  */
1229 int drbd_rs_del_all(struct drbd_device *device)
1230 {
1231         struct lc_element *e;
1232         struct bm_extent *bm_ext;
1233         int i;
1234
1235         spin_lock_irq(&device->al_lock);
1236
1237         if (get_ldev_if_state(device, D_FAILED)) {
1238                 /* ok, ->resync is there. */
1239                 for (i = 0; i < device->resync->nr_elements; i++) {
1240                         e = lc_element_by_index(device->resync, i);
1241                         bm_ext = lc_entry(e, struct bm_extent, lce);
1242                         if (bm_ext->lce.lc_number == LC_FREE)
1243                                 continue;
1244                         if (bm_ext->lce.lc_number == device->resync_wenr) {
1245                                 drbd_info(device, "dropping %u in drbd_rs_del_all, apparently"
1246                                      " got 'synced' by application io\n",
1247                                      device->resync_wenr);
1248                                 D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1249                                 D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1250                                 clear_bit(BME_NO_WRITES, &bm_ext->flags);
1251                                 device->resync_wenr = LC_FREE;
1252                                 lc_put(device->resync, &bm_ext->lce);
1253                         }
1254                         if (bm_ext->lce.refcnt != 0) {
1255                                 drbd_info(device, "Retrying drbd_rs_del_all() later. "
1256                                      "refcnt=%d\n", bm_ext->lce.refcnt);
1257                                 put_ldev(device);
1258                                 spin_unlock_irq(&device->al_lock);
1259                                 return -EAGAIN;
1260                         }
1261                         D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1262                         D_ASSERT(device, !test_bit(BME_NO_WRITES, &bm_ext->flags));
1263                         lc_del(device->resync, &bm_ext->lce);
1264                 }
1265                 D_ASSERT(device, device->resync->used == 0);
1266                 put_ldev(device);
1267         }
1268         spin_unlock_irq(&device->al_lock);
1269         wake_up(&device->al_wait);
1270
1271         return 0;
1272 }
1273
1274 /**
1275  * drbd_rs_failed_io() - Record information on a failure to resync the specified blocks
1276  * @device:     DRBD device.
1277  * @sector:     The sector number.
1278  * @size:       Size of failed IO operation, in byte.
1279  */
1280 void drbd_rs_failed_io(struct drbd_device *device, sector_t sector, int size)
1281 {
1282         /* Is called from worker and receiver context _only_ */
1283         unsigned long sbnr, ebnr, lbnr;
1284         unsigned long count;
1285         sector_t esector, nr_sectors;
1286         int wake_up = 0;
1287
1288         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_DISCARD_SIZE) {
1289                 drbd_err(device, "drbd_rs_failed_io: sector=%llus size=%d nonsense!\n",
1290                                 (unsigned long long)sector, size);
1291                 return;
1292         }
1293         nr_sectors = drbd_get_capacity(device->this_bdev);
1294         esector = sector + (size >> 9) - 1;
1295
1296         if (!expect(sector < nr_sectors))
1297                 return;
1298         if (!expect(esector < nr_sectors))
1299                 esector = nr_sectors - 1;
1300
1301         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
1302
1303         /*
1304          * round up start sector, round down end sector.  we make sure we only
1305          * handle full, aligned, BM_BLOCK_SIZE (4K) blocks */
1306         if (unlikely(esector < BM_SECT_PER_BIT-1))
1307                 return;
1308         if (unlikely(esector == (nr_sectors-1)))
1309                 ebnr = lbnr;
1310         else
1311                 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
1312         sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
1313
1314         if (sbnr > ebnr)
1315                 return;
1316
1317         /*
1318          * ok, (capacity & 7) != 0 sometimes, but who cares...
1319          * we count rs_{total,left} in bits, not sectors.
1320          */
1321         spin_lock_irq(&device->al_lock);
1322         count = drbd_bm_count_bits(device, sbnr, ebnr);
1323         if (count) {
1324                 device->rs_failed += count;
1325
1326                 if (get_ldev(device)) {
1327                         drbd_try_clear_on_disk_bm(device, sector, count, false);
1328                         put_ldev(device);
1329                 }
1330
1331                 /* just wake_up unconditional now, various lc_chaged(),
1332                  * lc_put() in drbd_try_clear_on_disk_bm(). */
1333                 wake_up = 1;
1334         }
1335         spin_unlock_irq(&device->al_lock);
1336         if (wake_up)
1337                 wake_up(&device->al_wait);
1338 }