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         struct drbd_device *device;
  99         unsigned int enr;
 100 };
 101
 102 struct update_al_work {
 103         struct drbd_work w;
 104         struct drbd_device *device;
 105         struct completion event;
 106         int err;
 107 };
 108
 109
 110 void *drbd_md_get_buffer(struct drbd_device *device)
 111 {
 112         int r;
 113
 114         wait_event(device->misc_wait,
 115                    (r = atomic_cmpxchg(&device->md_io_in_use, 0, 1)) == 0 ||
 116                    device->state.disk <= D_FAILED);
 117
 118         return r ? NULL : page_address(device->md_io_page);
 119 }
 120
 121 void drbd_md_put_buffer(struct drbd_device *device)
 122 {
 123         if (atomic_dec_and_test(&device->md_io_in_use))
 124                 wake_up(&device->misc_wait);
 125 }
 126
 127 void wait_until_done_or_force_detached(struct drbd_device *device, struct drbd_backing_dev *bdev,
 128                                      unsigned int *done)
 129 {
 130         long dt;
 131
 132         rcu_read_lock();
 133         dt = rcu_dereference(bdev->disk_conf)->disk_timeout;
 134         rcu_read_unlock();
 135         dt = dt * HZ / 10;
 136         if (dt == 0)
 137                 dt = MAX_SCHEDULE_TIMEOUT;
 138
 139         dt = wait_event_timeout(device->misc_wait,
 140                         *done || test_bit(FORCE_DETACH, &device->flags), dt);
 141         if (dt == 0) {
 142                 drbd_err(device, "meta-data IO operation timed out\n");
 143                 drbd_chk_io_error(device, 1, DRBD_FORCE_DETACH);
 144         }
 145 }
 146
 147 static int _drbd_md_sync_page_io(struct drbd_device *device,
 148                                  struct drbd_backing_dev *bdev,
 149                                  struct page *page, sector_t sector,
 150                                  int rw, int size)
 151 {
 152         struct bio *bio;
 153         int err;
 154
 155         device->md_io.done = 0;
 156         device->md_io.error = -ENODEV;
 157
 158         if ((rw & WRITE) && !test_bit(MD_NO_FUA, &device->flags))
 159                 rw |= REQ_FUA | REQ_FLUSH;
 160         rw |= REQ_SYNC;
 161
 162         bio = bio_alloc_drbd(GFP_NOIO);
 163         bio->bi_bdev = bdev->md_bdev;
 164         bio->bi_iter.bi_sector = sector;
 165         err = -EIO;
 166         if (bio_add_page(bio, page, size, 0) != size)
 167                 goto out;
 168         bio->bi_private = &device->md_io;
 169         bio->bi_end_io = drbd_md_io_complete;
 170         bio->bi_rw = rw;
 171
 172         if (!(rw & WRITE) && device->state.disk == D_DISKLESS && device->ldev == NULL)
 173                 /* special case, drbd_md_read() during drbd_adm_attach(): no get_ldev */
 174                 ;
 175         else if (!get_ldev_if_state(device, D_ATTACHING)) {
 176                 /* Corresponding put_ldev in drbd_md_io_complete() */
 177                 drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in _drbd_md_sync_page_io()\n");
 178                 err = -ENODEV;
 179                 goto out;
 180         }
 181
 182         bio_get(bio); /* one bio_put() is in the completion handler */
 183         atomic_inc(&device->md_io_in_use); /* drbd_md_put_buffer() is in the completion handler */
 184         if (drbd_insert_fault(device, (rw & WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
 185                 bio_endio(bio, -EIO);
 186         else
 187                 submit_bio(rw, bio);
 188         wait_until_done_or_force_detached(device, bdev, &device->md_io.done);
 189         if (bio_flagged(bio, BIO_UPTODATE))
 190                 err = device->md_io.error;
 191
 192  out:
 193         bio_put(bio);
 194         return err;
 195 }
 196
 197 int drbd_md_sync_page_io(struct drbd_device *device, struct drbd_backing_dev *bdev,
 198                          sector_t sector, int rw)
 199 {
 200         int err;
 201         struct page *iop = device->md_io_page;
 202
 203         D_ASSERT(device, atomic_read(&device->md_io_in_use) == 1);
 204
 205         BUG_ON(!bdev->md_bdev);
 206
 207         drbd_dbg(device, "meta_data io: %s [%d]:%s(,%llus,%s) %pS\n",
 208              current->comm, current->pid, __func__,
 209              (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ",
 210              (void*)_RET_IP_ );
 211
 212         if (sector < drbd_md_first_sector(bdev) ||
 213             sector + 7 > drbd_md_last_sector(bdev))
 214                 drbd_alert(device, "%s [%d]:%s(,%llus,%s) out of range md access!\n",
 215                      current->comm, current->pid, __func__,
 216                      (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ");
 217
 218         /* we do all our meta data IO in aligned 4k blocks. */
 219         err = _drbd_md_sync_page_io(device, bdev, iop, sector, rw, 4096);
 220         if (err) {
 221                 drbd_err(device, "drbd_md_sync_page_io(,%llus,%s) failed with error %d\n",
 222                     (unsigned long long)sector, (rw & WRITE) ? "WRITE" : "READ", err);
 223         }
 224         return err;
 225 }
 226
 227 static struct bm_extent *find_active_resync_extent(struct drbd_device *device, unsigned int enr)
 228 {
 229         struct lc_element *tmp;
 230         tmp = lc_find(device->resync, enr/AL_EXT_PER_BM_SECT);
 231         if (unlikely(tmp != NULL)) {
 232                 struct bm_extent  *bm_ext = lc_entry(tmp, struct bm_extent, lce);
 233                 if (test_bit(BME_NO_WRITES, &bm_ext->flags))
 234                         return bm_ext;
 235         }
 236         return NULL;
 237 }
 238
 239 static struct lc_element *_al_get(struct drbd_device *device, unsigned int enr, bool nonblock)
 240 {
 241         struct lc_element *al_ext;
 242         struct bm_extent *bm_ext;
 243         int wake;
 244
 245         spin_lock_irq(&device->al_lock);
 246         bm_ext = find_active_resync_extent(device, enr);
 247         if (bm_ext) {
 248                 wake = !test_and_set_bit(BME_PRIORITY, &bm_ext->flags);
 249                 spin_unlock_irq(&device->al_lock);
 250                 if (wake)
 251                         wake_up(&device->al_wait);
 252                 return NULL;
 253         }
 254         if (nonblock)
 255                 al_ext = lc_try_get(device->act_log, enr);
 256         else
 257                 al_ext = lc_get(device->act_log, enr);
 258         spin_unlock_irq(&device->al_lock);
 259         return al_ext;
 260 }
 261
 262 bool drbd_al_begin_io_fastpath(struct drbd_device *device, struct drbd_interval *i)
 263 {
 264         /* for bios crossing activity log extent boundaries,
 265          * we may need to activate two extents in one go */
 266         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 267         unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 268
 269         D_ASSERT(device, (unsigned)(last - first) <= 1);
 270         D_ASSERT(device, atomic_read(&device->local_cnt) > 0);
 271
 272         /* FIXME figure out a fast path for bios crossing AL extent boundaries */
 273         if (first != last)
 274                 return false;
 275
 276         return _al_get(device, first, true);
 277 }
 278
 279 static
 280 bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *i)
 281 {
 282         /* for bios crossing activity log extent boundaries,
 283          * we may need to activate two extents in one go */
 284         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 285         unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 286         unsigned enr;
 287         bool need_transaction = false;
 288
 289         D_ASSERT(device, first <= last);
 290         D_ASSERT(device, atomic_read(&device->local_cnt) > 0);
 291
 292         for (enr = first; enr <= last; enr++) {
 293                 struct lc_element *al_ext;
 294                 wait_event(device->al_wait,
 295                                 (al_ext = _al_get(device, enr, false)) != NULL);
 296                 if (al_ext->lc_number != enr)
 297                         need_transaction = true;
 298         }
 299         return need_transaction;
 300 }
 301
 302 static int al_write_transaction(struct drbd_device *device, bool delegate);
 303
 304 /* When called through generic_make_request(), we must delegate
 305  * activity log I/O to the worker thread: a further request
 306  * submitted via generic_make_request() within the same task
 307  * would be queued on current->bio_list, and would only start
 308  * after this function returns (see generic_make_request()).
 309  *
 310  * However, if we *are* the worker, we must not delegate to ourselves.
 311  */
 312
 313 /*
 314  * @delegate:   delegate activity log I/O to the worker thread
 315  */
 316 void drbd_al_begin_io_commit(struct drbd_device *device, bool delegate)
 317 {
 318         bool locked = false;
 319
 320         BUG_ON(delegate && current == first_peer_device(device)->connection->worker.task);
 321
 322         /* Serialize multiple transactions.
 323          * This uses test_and_set_bit, memory barrier is implicit.
 324          */
 325         wait_event(device->al_wait,
 326                         device->act_log->pending_changes == 0 ||
 327                         (locked = lc_try_lock_for_transaction(device->act_log)));
 328
 329         if (locked) {
 330                 /* Double check: it may have been committed by someone else,
 331                  * while we have been waiting for the lock. */
 332                 if (device->act_log->pending_changes) {
 333                         bool write_al_updates;
 334
 335                         rcu_read_lock();
 336                         write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
 337                         rcu_read_unlock();
 338
 339                         if (write_al_updates)
 340                                 al_write_transaction(device, delegate);
 341                         spin_lock_irq(&device->al_lock);
 342                         /* FIXME
 343                         if (err)
 344                                 we need an "lc_cancel" here;
 345                         */
 346                         lc_committed(device->act_log);
 347                         spin_unlock_irq(&device->al_lock);
 348                 }
 349                 lc_unlock(device->act_log);
 350                 wake_up(&device->al_wait);
 351         }
 352 }
 353
 354 /*
 355  * @delegate:   delegate activity log I/O to the worker thread
 356  */
 357 void drbd_al_begin_io(struct drbd_device *device, struct drbd_interval *i, bool delegate)
 358 {
 359         BUG_ON(delegate && current == first_peer_device(device)->connection->worker.task);
 360
 361         if (drbd_al_begin_io_prepare(device, i))
 362                 drbd_al_begin_io_commit(device, delegate);
 363 }
 364
 365 int drbd_al_begin_io_nonblock(struct drbd_device *device, struct drbd_interval *i)
 366 {
 367         struct lru_cache *al = device->act_log;
 368         /* for bios crossing activity log extent boundaries,
 369          * we may need to activate two extents in one go */
 370         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 371         unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 372         unsigned nr_al_extents;
 373         unsigned available_update_slots;
 374         unsigned enr;
 375
 376         D_ASSERT(device, first <= last);
 377
 378         nr_al_extents = 1 + last - first; /* worst case: all touched extends are cold. */
 379         available_update_slots = min(al->nr_elements - al->used,
 380                                 al->max_pending_changes - al->pending_changes);
 381
 382         /* We want all necessary updates for a given request within the same transaction
 383          * We could first check how many updates are *actually* needed,
 384          * and use that instead of the worst-case nr_al_extents */
 385         if (available_update_slots < nr_al_extents)
 386                 return -EWOULDBLOCK;
 387
 388         /* Is resync active in this area? */
 389         for (enr = first; enr <= last; enr++) {
 390                 struct lc_element *tmp;
 391                 tmp = lc_find(device->resync, enr/AL_EXT_PER_BM_SECT);
 392                 if (unlikely(tmp != NULL)) {
 393                         struct bm_extent  *bm_ext = lc_entry(tmp, struct bm_extent, lce);
 394                         if (test_bit(BME_NO_WRITES, &bm_ext->flags)) {
 395                                 if (!test_and_set_bit(BME_PRIORITY, &bm_ext->flags))
 396                                         return -EBUSY;
 397                                 return -EWOULDBLOCK;
 398                         }
 399                 }
 400         }
 401
 402         /* Checkout the refcounts.
 403          * Given that we checked for available elements and update slots above,
 404          * this has to be successful. */
 405         for (enr = first; enr <= last; enr++) {
 406                 struct lc_element *al_ext;
 407                 al_ext = lc_get_cumulative(device->act_log, enr);
 408                 if (!al_ext)
 409                         drbd_info(device, "LOGIC BUG for enr=%u\n", enr);
 410         }
 411         return 0;
 412 }
 413
 414 void drbd_al_complete_io(struct drbd_device *device, struct drbd_interval *i)
 415 {
 416         /* for bios crossing activity log extent boundaries,
 417          * we may need to activate two extents in one go */
 418         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 419         unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 420         unsigned enr;
 421         struct lc_element *extent;
 422         unsigned long flags;
 423
 424         D_ASSERT(device, first <= last);
 425         spin_lock_irqsave(&device->al_lock, flags);
 426
 427         for (enr = first; enr <= last; enr++) {
 428                 extent = lc_find(device->act_log, enr);
 429                 if (!extent) {
 430                         drbd_err(device, "al_complete_io() called on inactive extent %u\n", enr);
 431                         continue;
 432                 }
 433                 lc_put(device->act_log, extent);
 434         }
 435         spin_unlock_irqrestore(&device->al_lock, flags);
 436         wake_up(&device->al_wait);
 437 }
 438
 439 #if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
 440 /* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
 441  * are still coupled, or assume too much about their relation.
 442  * Code below will not work if this is violated.
 443  * Will be cleaned up with some followup patch.
 444  */
 445 # error FIXME
 446 #endif
 447
 448 static unsigned int al_extent_to_bm_page(unsigned int al_enr)
 449 {
 450         return al_enr >>
 451                 /* bit to page */
 452                 ((PAGE_SHIFT + 3) -
 453                 /* al extent number to bit */
 454                  (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
 455 }
 456
 457 static unsigned int rs_extent_to_bm_page(unsigned int rs_enr)
 458 {
 459         return rs_enr >>
 460                 /* bit to page */
 461                 ((PAGE_SHIFT + 3) -
 462                 /* resync extent number to bit */
 463                  (BM_EXT_SHIFT - BM_BLOCK_SHIFT));
 464 }
 465
 466 static sector_t al_tr_number_to_on_disk_sector(struct drbd_device *device)
 467 {
 468         const unsigned int stripes = device->ldev->md.al_stripes;
 469         const unsigned int stripe_size_4kB = device->ldev->md.al_stripe_size_4k;
 470
 471         /* transaction number, modulo on-disk ring buffer wrap around */
 472         unsigned int t = device->al_tr_number % (device->ldev->md.al_size_4k);
 473
 474         /* ... to aligned 4k on disk block */
 475         t = ((t % stripes) * stripe_size_4kB) + t/stripes;
 476
 477         /* ... to 512 byte sector in activity log */
 478         t *= 8;
 479
 480         /* ... plus offset to the on disk position */
 481         return device->ldev->md.md_offset + device->ldev->md.al_offset + t;
 482 }
 483
 484 static int
 485 _al_write_transaction(struct drbd_device *device)
 486 {
 487         struct al_transaction_on_disk *buffer;
 488         struct lc_element *e;
 489         sector_t sector;
 490         int i, mx;
 491         unsigned extent_nr;
 492         unsigned crc = 0;
 493         int err = 0;
 494
 495         if (!get_ldev(device)) {
 496                 drbd_err(device, "disk is %s, cannot start al transaction\n",
 497                         drbd_disk_str(device->state.disk));
 498                 return -EIO;
 499         }
 500
 501         /* The bitmap write may have failed, causing a state change. */
 502         if (device->state.disk < D_INCONSISTENT) {
 503                 drbd_err(device,
 504                         "disk is %s, cannot write al transaction\n",
 505                         drbd_disk_str(device->state.disk));
 506                 put_ldev(device);
 507                 return -EIO;
 508         }
 509
 510         buffer = drbd_md_get_buffer(device); /* protects md_io_buffer, al_tr_cycle, ... */
 511         if (!buffer) {
 512                 drbd_err(device, "disk failed while waiting for md_io buffer\n");
 513                 put_ldev(device);
 514                 return -ENODEV;
 515         }
 516
 517         memset(buffer, 0, sizeof(*buffer));
 518         buffer->magic = cpu_to_be32(DRBD_AL_MAGIC);
 519         buffer->tr_number = cpu_to_be32(device->al_tr_number);
 520
 521         i = 0;
 522
 523         /* Even though no one can start to change this list
 524          * once we set the LC_LOCKED -- from drbd_al_begin_io(),
 525          * lc_try_lock_for_transaction() --, someone may still
 526          * be in the process of changing it. */
 527         spin_lock_irq(&device->al_lock);
 528         list_for_each_entry(e, &device->act_log->to_be_changed, list) {
 529                 if (i == AL_UPDATES_PER_TRANSACTION) {
 530                         i++;
 531                         break;
 532                 }
 533                 buffer->update_slot_nr[i] = cpu_to_be16(e->lc_index);
 534                 buffer->update_extent_nr[i] = cpu_to_be32(e->lc_new_number);
 535                 if (e->lc_number != LC_FREE)
 536                         drbd_bm_mark_for_writeout(device,
 537                                         al_extent_to_bm_page(e->lc_number));
 538                 i++;
 539         }
 540         spin_unlock_irq(&device->al_lock);
 541         BUG_ON(i > AL_UPDATES_PER_TRANSACTION);
 542
 543         buffer->n_updates = cpu_to_be16(i);
 544         for ( ; i < AL_UPDATES_PER_TRANSACTION; i++) {
 545                 buffer->update_slot_nr[i] = cpu_to_be16(-1);
 546                 buffer->update_extent_nr[i] = cpu_to_be32(LC_FREE);
 547         }
 548
 549         buffer->context_size = cpu_to_be16(device->act_log->nr_elements);
 550         buffer->context_start_slot_nr = cpu_to_be16(device->al_tr_cycle);
 551
 552         mx = min_t(int, AL_CONTEXT_PER_TRANSACTION,
 553                    device->act_log->nr_elements - device->al_tr_cycle);
 554         for (i = 0; i < mx; i++) {
 555                 unsigned idx = device->al_tr_cycle + i;
 556                 extent_nr = lc_element_by_index(device->act_log, idx)->lc_number;
 557                 buffer->context[i] = cpu_to_be32(extent_nr);
 558         }
 559         for (; i < AL_CONTEXT_PER_TRANSACTION; i++)
 560                 buffer->context[i] = cpu_to_be32(LC_FREE);
 561
 562         device->al_tr_cycle += AL_CONTEXT_PER_TRANSACTION;
 563         if (device->al_tr_cycle >= device->act_log->nr_elements)
 564                 device->al_tr_cycle = 0;
 565
 566         sector = al_tr_number_to_on_disk_sector(device);
 567
 568         crc = crc32c(0, buffer, 4096);
 569         buffer->crc32c = cpu_to_be32(crc);
 570
 571         if (drbd_bm_write_hinted(device))
 572                 err = -EIO;
 573         else {
 574                 bool write_al_updates;
 575                 rcu_read_lock();
 576                 write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
 577                 rcu_read_unlock();
 578                 if (write_al_updates) {
 579                         if (drbd_md_sync_page_io(device, device->ldev, sector, WRITE)) {
 580                                 err = -EIO;
 581                                 drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR);
 582                         } else {
 583                                 device->al_tr_number++;
 584                                 device->al_writ_cnt++;
 585                         }
 586                 }
 587         }
 588
 589         drbd_md_put_buffer(device);
 590         put_ldev(device);
 591
 592         return err;
 593 }
 594
 595
 596 static int w_al_write_transaction(struct drbd_work *w, int unused)
 597 {
 598         struct update_al_work *aw = container_of(w, struct update_al_work, w);
 599         struct drbd_device *device = aw->device;
 600         int err;
 601
 602         err = _al_write_transaction(device);
 603         aw->err = err;
 604         complete(&aw->event);
 605
 606         return err != -EIO ? err : 0;
 607 }
 608
 609 /* Calls from worker context (see w_restart_disk_io()) need to write the
 610    transaction directly. Others came through generic_make_request(),
 611    those need to delegate it to the worker. */
 612 static int al_write_transaction(struct drbd_device *device, bool delegate)
 613 {
 614         if (delegate) {
 615                 struct update_al_work al_work;
 616                 init_completion(&al_work.event);
 617                 al_work.w.cb = w_al_write_transaction;
 618                 al_work.device = device;
 619                 drbd_queue_work_front(&first_peer_device(device)->connection->sender_work,
 620                                       &al_work.w);
 621                 wait_for_completion(&al_work.event);
 622                 return al_work.err;
 623         } else
 624                 return _al_write_transaction(device);
 625 }
 626
 627 static int _try_lc_del(struct drbd_device *device, struct lc_element *al_ext)
 628 {
 629         int rv;
 630
 631         spin_lock_irq(&device->al_lock);
 632         rv = (al_ext->refcnt == 0);
 633         if (likely(rv))
 634                 lc_del(device->act_log, al_ext);
 635         spin_unlock_irq(&device->al_lock);
 636
 637         return rv;
 638 }
 639
 640 /**
 641  * drbd_al_shrink() - Removes all active extents form the activity log
 642  * @device:     DRBD device.
 643  *
 644  * Removes all active extents form the activity log, waiting until
 645  * the reference count of each entry dropped to 0 first, of course.
 646  *
 647  * You need to lock device->act_log with lc_try_lock() / lc_unlock()
 648  */
 649 void drbd_al_shrink(struct drbd_device *device)
 650 {
 651         struct lc_element *al_ext;
 652         int i;
 653
 654         D_ASSERT(device, test_bit(__LC_LOCKED, &device->act_log->flags));
 655
 656         for (i = 0; i < device->act_log->nr_elements; i++) {
 657                 al_ext = lc_element_by_index(device->act_log, i);
 658                 if (al_ext->lc_number == LC_FREE)
 659                         continue;
 660                 wait_event(device->al_wait, _try_lc_del(device, al_ext));
 661         }
 662
 663         wake_up(&device->al_wait);
 664 }
 665
 666 int drbd_initialize_al(struct drbd_device *device, void *buffer)
 667 {
 668         struct al_transaction_on_disk *al = buffer;
 669         struct drbd_md *md = &device->ldev->md;
 670         sector_t al_base = md->md_offset + md->al_offset;
 671         int al_size_4k = md->al_stripes * md->al_stripe_size_4k;
 672         int i;
 673
 674         memset(al, 0, 4096);
 675         al->magic = cpu_to_be32(DRBD_AL_MAGIC);
 676         al->transaction_type = cpu_to_be16(AL_TR_INITIALIZED);
 677         al->crc32c = cpu_to_be32(crc32c(0, al, 4096));
 678
 679         for (i = 0; i < al_size_4k; i++) {
 680                 int err = drbd_md_sync_page_io(device, device->ldev, al_base + i * 8, WRITE);
 681                 if (err)
 682                         return err;
 683         }
 684         return 0;
 685 }
 686
 687 static int w_update_odbm(struct drbd_work *w, int unused)
 688 {
 689         struct update_odbm_work *udw = container_of(w, struct update_odbm_work, w);
 690         struct drbd_device *device = udw->device;
 691         struct sib_info sib = { .sib_reason = SIB_SYNC_PROGRESS, };
 692
 693         if (!get_ldev(device)) {
 694                 if (__ratelimit(&drbd_ratelimit_state))
 695                         drbd_warn(device, "Can not update on disk bitmap, local IO disabled.\n");
 696                 kfree(udw);
 697                 return 0;
 698         }
 699
 700         drbd_bm_write_page(device, rs_extent_to_bm_page(udw->enr));
 701         put_ldev(device);
 702
 703         kfree(udw);
 704
 705         if (drbd_bm_total_weight(device) <= device->rs_failed) {
 706                 switch (device->state.conn) {
 707                 case C_SYNC_SOURCE:  case C_SYNC_TARGET:
 708                 case C_PAUSED_SYNC_S: case C_PAUSED_SYNC_T:
 709                         drbd_resync_finished(device);
 710                 default:
 711                         /* nothing to do */
 712                         break;
 713                 }
 714         }
 715         drbd_bcast_event(device, &sib);
 716
 717         return 0;
 718 }
 719
 720
 721 /* ATTENTION. The AL's extents are 4MB each, while the extents in the
 722  * resync LRU-cache are 16MB each.
 723  * The caller of this function has to hold an get_ldev() reference.
 724  *
 725  * TODO will be obsoleted once we have a caching lru of the on disk bitmap
 726  */
 727 static void drbd_try_clear_on_disk_bm(struct drbd_device *device, sector_t sector,
 728                                       int count, int success)
 729 {
 730         struct lc_element *e;
 731         struct update_odbm_work *udw;
 732
 733         unsigned int enr;
 734
 735         D_ASSERT(device, atomic_read(&device->local_cnt));
 736
 737         /* I simply assume that a sector/size pair never crosses
 738          * a 16 MB extent border. (Currently this is true...) */
 739         enr = BM_SECT_TO_EXT(sector);
 740
 741         e = lc_get(device->resync, enr);
 742         if (e) {
 743                 struct bm_extent *ext = lc_entry(e, struct bm_extent, lce);
 744                 if (ext->lce.lc_number == enr) {
 745                         if (success)
 746                                 ext->rs_left -= count;
 747                         else
 748                                 ext->rs_failed += count;
 749                         if (ext->rs_left < ext->rs_failed) {
 750                                 drbd_warn(device, "BAD! sector=%llus enr=%u rs_left=%d "
 751                                     "rs_failed=%d count=%d cstate=%s\n",
 752                                      (unsigned long long)sector,
 753                                      ext->lce.lc_number, ext->rs_left,
 754                                      ext->rs_failed, count,
 755                                      drbd_conn_str(device->state.conn));
 756
 757                                 /* We don't expect to be able to clear more bits
 758                                  * than have been set when we originally counted
 759                                  * the set bits to cache that value in ext->rs_left.
 760                                  * Whatever the reason (disconnect during resync,
 761                                  * delayed local completion of an application write),
 762                                  * try to fix it up by recounting here. */
 763                                 ext->rs_left = drbd_bm_e_weight(device, enr);
 764                         }
 765                 } else {
 766                         /* Normally this element should be in the cache,
 767                          * since drbd_rs_begin_io() pulled it already in.
 768                          *
 769                          * But maybe an application write finished, and we set
 770                          * something outside the resync lru_cache in sync.
 771                          */
 772                         int rs_left = drbd_bm_e_weight(device, enr);
 773                         if (ext->flags != 0) {
 774                                 drbd_warn(device, "changing resync lce: %d[%u;%02lx]"
 775                                      " -> %d[%u;00]\n",
 776                                      ext->lce.lc_number, ext->rs_left,
 777                                      ext->flags, enr, rs_left);
 778                                 ext->flags = 0;
 779                         }
 780                         if (ext->rs_failed) {
 781                                 drbd_warn(device, "Kicking resync_lru element enr=%u "
 782                                      "out with rs_failed=%d\n",
 783                                      ext->lce.lc_number, ext->rs_failed);
 784                         }
 785                         ext->rs_left = rs_left;
 786                         ext->rs_failed = success ? 0 : count;
 787                         /* we don't keep a persistent log of the resync lru,
 788                          * we can commit any change right away. */
 789                         lc_committed(device->resync);
 790                 }
 791                 lc_put(device->resync, &ext->lce);
 792                 /* no race, we are within the al_lock! */
 793
 794                 if (ext->rs_left == ext->rs_failed) {
 795                         ext->rs_failed = 0;
 796
 797                         udw = kmalloc(sizeof(*udw), GFP_ATOMIC);
 798                         if (udw) {
 799                                 udw->enr = ext->lce.lc_number;
 800                                 udw->w.cb = w_update_odbm;
 801                                 udw->device = device;
 802                                 drbd_queue_work_front(&first_peer_device(device)->connection->sender_work,
 803                                                       &udw->w);
 804                         } else {
 805                                 drbd_warn(device, "Could not kmalloc an udw\n");
 806                         }
 807                 }
 808         } else {
 809                 drbd_err(device, "lc_get() failed! locked=%d/%d flags=%lu\n",
 810                     device->resync_locked,
 811                     device->resync->nr_elements,
 812                     device->resync->flags);
 813         }
 814 }
 815
 816 void drbd_advance_rs_marks(struct drbd_device *device, unsigned long still_to_go)
 817 {
 818         unsigned long now = jiffies;
 819         unsigned long last = device->rs_mark_time[device->rs_last_mark];
 820         int next = (device->rs_last_mark + 1) % DRBD_SYNC_MARKS;
 821         if (time_after_eq(now, last + DRBD_SYNC_MARK_STEP)) {
 822                 if (device->rs_mark_left[device->rs_last_mark] != still_to_go &&
 823                     device->state.conn != C_PAUSED_SYNC_T &&
 824                     device->state.conn != C_PAUSED_SYNC_S) {
 825                         device->rs_mark_time[next] = now;
 826                         device->rs_mark_left[next] = still_to_go;
 827                         device->rs_last_mark = next;
 828                 }
 829         }
 830 }
 831
 832 /* clear the bit corresponding to the piece of storage in question:
 833  * size byte of data starting from sector.  Only clear a bits of the affected
 834  * one ore more _aligned_ BM_BLOCK_SIZE blocks.
 835  *
 836  * called by worker on C_SYNC_TARGET and receiver on SyncSource.
 837  *
 838  */
 839 void __drbd_set_in_sync(struct drbd_device *device, sector_t sector, int size,
 840                        const char *file, const unsigned int line)
 841 {
 842         /* Is called from worker and receiver context _only_ */
 843         unsigned long sbnr, ebnr, lbnr;
 844         unsigned long count = 0;
 845         sector_t esector, nr_sectors;
 846         int wake_up = 0;
 847         unsigned long flags;
 848
 849         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
 850                 drbd_err(device, "drbd_set_in_sync: sector=%llus size=%d nonsense!\n",
 851                                 (unsigned long long)sector, size);
 852                 return;
 853         }
 854
 855         if (!get_ldev(device))
 856                 return; /* no disk, no metadata, no bitmap to clear bits in */
 857
 858         nr_sectors = drbd_get_capacity(device->this_bdev);
 859         esector = sector + (size >> 9) - 1;
 860
 861         if (!expect(sector < nr_sectors))
 862                 goto out;
 863         if (!expect(esector < nr_sectors))
 864                 esector = nr_sectors - 1;
 865
 866         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
 867
 868         /* we clear it (in sync).
 869          * round up start sector, round down end sector.  we make sure we only
 870          * clear full, aligned, BM_BLOCK_SIZE (4K) blocks */
 871         if (unlikely(esector < BM_SECT_PER_BIT-1))
 872                 goto out;
 873         if (unlikely(esector == (nr_sectors-1)))
 874                 ebnr = lbnr;
 875         else
 876                 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
 877         sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
 878
 879         if (sbnr > ebnr)
 880                 goto out;
 881
 882         /*
 883          * ok, (capacity & 7) != 0 sometimes, but who cares...
 884          * we count rs_{total,left} in bits, not sectors.
 885          */
 886         count = drbd_bm_clear_bits(device, sbnr, ebnr);
 887         if (count) {
 888                 drbd_advance_rs_marks(device, drbd_bm_total_weight(device));
 889                 spin_lock_irqsave(&device->al_lock, flags);
 890                 drbd_try_clear_on_disk_bm(device, sector, count, true);
 891                 spin_unlock_irqrestore(&device->al_lock, flags);
 892
 893                 /* just wake_up unconditional now, various lc_chaged(),
 894                  * lc_put() in drbd_try_clear_on_disk_bm(). */
 895                 wake_up = 1;
 896         }
 897 out:
 898         put_ldev(device);
 899         if (wake_up)
 900                 wake_up(&device->al_wait);
 901 }
 902
 903 /*
 904  * this is intended to set one request worth of data out of sync.
 905  * affects at least 1 bit,
 906  * and at most 1+DRBD_MAX_BIO_SIZE/BM_BLOCK_SIZE bits.
 907  *
 908  * called by tl_clear and drbd_send_dblock (==drbd_make_request).
 909  * so this can be _any_ process.
 910  */
 911 int __drbd_set_out_of_sync(struct drbd_device *device, sector_t sector, int size,
 912                             const char *file, const unsigned int line)
 913 {
 914         unsigned long sbnr, ebnr, flags;
 915         sector_t esector, nr_sectors;
 916         unsigned int enr, count = 0;
 917         struct lc_element *e;
 918
 919         /* this should be an empty REQ_FLUSH */
 920         if (size == 0)
 921                 return 0;
 922
 923         if (size < 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
 924                 drbd_err(device, "sector: %llus, size: %d\n",
 925                         (unsigned long long)sector, size);
 926                 return 0;
 927         }
 928
 929         if (!get_ldev(device))
 930                 return 0; /* no disk, no metadata, no bitmap to set bits in */
 931
 932         nr_sectors = drbd_get_capacity(device->this_bdev);
 933         esector = sector + (size >> 9) - 1;
 934
 935         if (!expect(sector < nr_sectors))
 936                 goto out;
 937         if (!expect(esector < nr_sectors))
 938                 esector = nr_sectors - 1;
 939
 940         /* we set it out of sync,
 941          * we do not need to round anything here */
 942         sbnr = BM_SECT_TO_BIT(sector);
 943         ebnr = BM_SECT_TO_BIT(esector);
 944
 945         /* ok, (capacity & 7) != 0 sometimes, but who cares...
 946          * we count rs_{total,left} in bits, not sectors.  */
 947         spin_lock_irqsave(&device->al_lock, flags);
 948         count = drbd_bm_set_bits(device, sbnr, ebnr);
 949
 950         enr = BM_SECT_TO_EXT(sector);
 951         e = lc_find(device->resync, enr);
 952         if (e)
 953                 lc_entry(e, struct bm_extent, lce)->rs_left += count;
 954         spin_unlock_irqrestore(&device->al_lock, flags);
 955
 956 out:
 957         put_ldev(device);
 958
 959         return count;
 960 }
 961
 962 static
 963 struct bm_extent *_bme_get(struct drbd_device *device, unsigned int enr)
 964 {
 965         struct lc_element *e;
 966         struct bm_extent *bm_ext;
 967         int wakeup = 0;
 968         unsigned long rs_flags;
 969
 970         spin_lock_irq(&device->al_lock);
 971         if (device->resync_locked > device->resync->nr_elements/2) {
 972                 spin_unlock_irq(&device->al_lock);
 973                 return NULL;
 974         }
 975         e = lc_get(device->resync, enr);
 976         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
 977         if (bm_ext) {
 978                 if (bm_ext->lce.lc_number != enr) {
 979                         bm_ext->rs_left = drbd_bm_e_weight(device, enr);
 980                         bm_ext->rs_failed = 0;
 981                         lc_committed(device->resync);
 982                         wakeup = 1;
 983                 }
 984                 if (bm_ext->lce.refcnt == 1)
 985                         device->resync_locked++;
 986                 set_bit(BME_NO_WRITES, &bm_ext->flags);
 987         }
 988         rs_flags = device->resync->flags;
 989         spin_unlock_irq(&device->al_lock);
 990         if (wakeup)
 991                 wake_up(&device->al_wait);
 992
 993         if (!bm_ext) {
 994                 if (rs_flags & LC_STARVING)
 995                         drbd_warn(device, "Have to wait for element"
 996                              " (resync LRU too small?)\n");
 997                 BUG_ON(rs_flags & LC_LOCKED);
 998         }
 999
1000         return bm_ext;
1001 }
1002
1003 static int _is_in_al(struct drbd_device *device, unsigned int enr)
1004 {
1005         int rv;
1006
1007         spin_lock_irq(&device->al_lock);
1008         rv = lc_is_used(device->act_log, enr);
1009         spin_unlock_irq(&device->al_lock);
1010
1011         return rv;
1012 }
1013
1014 /**
1015  * drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED
1016  * @device:     DRBD device.
1017  * @sector:     The sector number.
1018  *
1019  * This functions sleeps on al_wait. Returns 0 on success, -EINTR if interrupted.
1020  */
1021 int drbd_rs_begin_io(struct drbd_device *device, sector_t sector)
1022 {
1023         unsigned int enr = BM_SECT_TO_EXT(sector);
1024         struct bm_extent *bm_ext;
1025         int i, sig;
1026         int sa = 200; /* Step aside 200 times, then grab the extent and let app-IO wait.
1027                          200 times -> 20 seconds. */
1028
1029 retry:
1030         sig = wait_event_interruptible(device->al_wait,
1031                         (bm_ext = _bme_get(device, enr)));
1032         if (sig)
1033                 return -EINTR;
1034
1035         if (test_bit(BME_LOCKED, &bm_ext->flags))
1036                 return 0;
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                                                test_bit(BME_PRIORITY, &bm_ext->flags));
1042
1043                 if (sig || (test_bit(BME_PRIORITY, &bm_ext->flags) && sa)) {
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                         if (sa && --sa == 0)
1056                                 drbd_warn(device, "drbd_rs_begin_io() stepped aside for 20sec."
1057                                          "Resync stalled?\n");
1058                         goto retry;
1059                 }
1060         }
1061         set_bit(BME_LOCKED, &bm_ext->flags);
1062         return 0;
1063 }
1064
1065 /**
1066  * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
1067  * @device:     DRBD device.
1068  * @sector:     The sector number.
1069  *
1070  * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
1071  * tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN
1072  * if there is still application IO going on in this area.
1073  */
1074 int drbd_try_rs_begin_io(struct drbd_device *device, sector_t sector)
1075 {
1076         unsigned int enr = BM_SECT_TO_EXT(sector);
1077         const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT;
1078         struct lc_element *e;
1079         struct bm_extent *bm_ext;
1080         int i;
1081
1082         spin_lock_irq(&device->al_lock);
1083         if (device->resync_wenr != LC_FREE && device->resync_wenr != enr) {
1084                 /* in case you have very heavy scattered io, it may
1085                  * stall the syncer undefined if we give up the ref count
1086                  * when we try again and requeue.
1087                  *
1088                  * if we don't give up the refcount, but the next time
1089                  * we are scheduled this extent has been "synced" by new
1090                  * application writes, we'd miss the lc_put on the
1091                  * extent we keep the refcount on.
1092                  * so we remembered which extent we had to try again, and
1093                  * if the next requested one is something else, we do
1094                  * the lc_put here...
1095                  * we also have to wake_up
1096                  */
1097                 e = lc_find(device->resync, device->resync_wenr);
1098                 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1099                 if (bm_ext) {
1100                         D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1101                         D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1102                         clear_bit(BME_NO_WRITES, &bm_ext->flags);
1103                         device->resync_wenr = LC_FREE;
1104                         if (lc_put(device->resync, &bm_ext->lce) == 0)
1105                                 device->resync_locked--;
1106                         wake_up(&device->al_wait);
1107                 } else {
1108                         drbd_alert(device, "LOGIC BUG\n");
1109                 }
1110         }
1111         /* TRY. */
1112         e = lc_try_get(device->resync, enr);
1113         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1114         if (bm_ext) {
1115                 if (test_bit(BME_LOCKED, &bm_ext->flags))
1116                         goto proceed;
1117                 if (!test_and_set_bit(BME_NO_WRITES, &bm_ext->flags)) {
1118                         device->resync_locked++;
1119                 } else {
1120                         /* we did set the BME_NO_WRITES,
1121                          * but then could not set BME_LOCKED,
1122                          * so we tried again.
1123                          * drop the extra reference. */
1124                         bm_ext->lce.refcnt--;
1125                         D_ASSERT(device, bm_ext->lce.refcnt > 0);
1126                 }
1127                 goto check_al;
1128         } else {
1129                 /* do we rather want to try later? */
1130                 if (device->resync_locked > device->resync->nr_elements-3)
1131                         goto try_again;
1132                 /* Do or do not. There is no try. -- Yoda */
1133                 e = lc_get(device->resync, enr);
1134                 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1135                 if (!bm_ext) {
1136                         const unsigned long rs_flags = device->resync->flags;
1137                         if (rs_flags & LC_STARVING)
1138                                 drbd_warn(device, "Have to wait for element"
1139                                      " (resync LRU too small?)\n");
1140                         BUG_ON(rs_flags & LC_LOCKED);
1141                         goto try_again;
1142                 }
1143                 if (bm_ext->lce.lc_number != enr) {
1144                         bm_ext->rs_left = drbd_bm_e_weight(device, enr);
1145                         bm_ext->rs_failed = 0;
1146                         lc_committed(device->resync);
1147                         wake_up(&device->al_wait);
1148                         D_ASSERT(device, test_bit(BME_LOCKED, &bm_ext->flags) == 0);
1149                 }
1150                 set_bit(BME_NO_WRITES, &bm_ext->flags);
1151                 D_ASSERT(device, bm_ext->lce.refcnt == 1);
1152                 device->resync_locked++;
1153                 goto check_al;
1154         }
1155 check_al:
1156         for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
1157                 if (lc_is_used(device->act_log, al_enr+i))
1158                         goto try_again;
1159         }
1160         set_bit(BME_LOCKED, &bm_ext->flags);
1161 proceed:
1162         device->resync_wenr = LC_FREE;
1163         spin_unlock_irq(&device->al_lock);
1164         return 0;
1165
1166 try_again:
1167         if (bm_ext)
1168                 device->resync_wenr = enr;
1169         spin_unlock_irq(&device->al_lock);
1170         return -EAGAIN;
1171 }
1172
1173 void drbd_rs_complete_io(struct drbd_device *device, sector_t sector)
1174 {
1175         unsigned int enr = BM_SECT_TO_EXT(sector);
1176         struct lc_element *e;
1177         struct bm_extent *bm_ext;
1178         unsigned long flags;
1179
1180         spin_lock_irqsave(&device->al_lock, flags);
1181         e = lc_find(device->resync, enr);
1182         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1183         if (!bm_ext) {
1184                 spin_unlock_irqrestore(&device->al_lock, flags);
1185                 if (__ratelimit(&drbd_ratelimit_state))
1186                         drbd_err(device, "drbd_rs_complete_io() called, but extent not found\n");
1187                 return;
1188         }
1189
1190         if (bm_ext->lce.refcnt == 0) {
1191                 spin_unlock_irqrestore(&device->al_lock, flags);
1192                 drbd_err(device, "drbd_rs_complete_io(,%llu [=%u]) called, "
1193                     "but refcnt is 0!?\n",
1194                     (unsigned long long)sector, enr);
1195                 return;
1196         }
1197
1198         if (lc_put(device->resync, &bm_ext->lce) == 0) {
1199                 bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */
1200                 device->resync_locked--;
1201                 wake_up(&device->al_wait);
1202         }
1203
1204         spin_unlock_irqrestore(&device->al_lock, flags);
1205 }
1206
1207 /**
1208  * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
1209  * @device:     DRBD device.
1210  */
1211 void drbd_rs_cancel_all(struct drbd_device *device)
1212 {
1213         spin_lock_irq(&device->al_lock);
1214
1215         if (get_ldev_if_state(device, D_FAILED)) { /* Makes sure ->resync is there. */
1216                 lc_reset(device->resync);
1217                 put_ldev(device);
1218         }
1219         device->resync_locked = 0;
1220         device->resync_wenr = LC_FREE;
1221         spin_unlock_irq(&device->al_lock);
1222         wake_up(&device->al_wait);
1223 }
1224
1225 /**
1226  * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
1227  * @device:     DRBD device.
1228  *
1229  * Returns 0 upon success, -EAGAIN if at least one reference count was
1230  * not zero.
1231  */
1232 int drbd_rs_del_all(struct drbd_device *device)
1233 {
1234         struct lc_element *e;
1235         struct bm_extent *bm_ext;
1236         int i;
1237
1238         spin_lock_irq(&device->al_lock);
1239
1240         if (get_ldev_if_state(device, D_FAILED)) {
1241                 /* ok, ->resync is there. */
1242                 for (i = 0; i < device->resync->nr_elements; i++) {
1243                         e = lc_element_by_index(device->resync, i);
1244                         bm_ext = lc_entry(e, struct bm_extent, lce);
1245                         if (bm_ext->lce.lc_number == LC_FREE)
1246                                 continue;
1247                         if (bm_ext->lce.lc_number == device->resync_wenr) {
1248                                 drbd_info(device, "dropping %u in drbd_rs_del_all, apparently"
1249                                      " got 'synced' by application io\n",
1250                                      device->resync_wenr);
1251                                 D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1252                                 D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1253                                 clear_bit(BME_NO_WRITES, &bm_ext->flags);
1254                                 device->resync_wenr = LC_FREE;
1255                                 lc_put(device->resync, &bm_ext->lce);
1256                         }
1257                         if (bm_ext->lce.refcnt != 0) {
1258                                 drbd_info(device, "Retrying drbd_rs_del_all() later. "
1259                                      "refcnt=%d\n", bm_ext->lce.refcnt);
1260                                 put_ldev(device);
1261                                 spin_unlock_irq(&device->al_lock);
1262                                 return -EAGAIN;
1263                         }
1264                         D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1265                         D_ASSERT(device, !test_bit(BME_NO_WRITES, &bm_ext->flags));
1266                         lc_del(device->resync, &bm_ext->lce);
1267                 }
1268                 D_ASSERT(device, device->resync->used == 0);
1269                 put_ldev(device);
1270         }
1271         spin_unlock_irq(&device->al_lock);
1272         wake_up(&device->al_wait);
1273
1274         return 0;
1275 }
1276
1277 /**
1278  * drbd_rs_failed_io() - Record information on a failure to resync the specified blocks
1279  * @device:     DRBD device.
1280  * @sector:     The sector number.
1281  * @size:       Size of failed IO operation, in byte.
1282  */
1283 void drbd_rs_failed_io(struct drbd_device *device, sector_t sector, int size)
1284 {
1285         /* Is called from worker and receiver context _only_ */
1286         unsigned long sbnr, ebnr, lbnr;
1287         unsigned long count;
1288         sector_t esector, nr_sectors;
1289         int wake_up = 0;
1290
1291         if (size <= 0 || !IS_ALIGNED(size, 512) || size > DRBD_MAX_BIO_SIZE) {
1292                 drbd_err(device, "drbd_rs_failed_io: sector=%llus size=%d nonsense!\n",
1293                                 (unsigned long long)sector, size);
1294                 return;
1295         }
1296         nr_sectors = drbd_get_capacity(device->this_bdev);
1297         esector = sector + (size >> 9) - 1;
1298
1299         if (!expect(sector < nr_sectors))
1300                 return;
1301         if (!expect(esector < nr_sectors))
1302                 esector = nr_sectors - 1;
1303
1304         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
1305
1306         /*
1307          * round up start sector, round down end sector.  we make sure we only
1308          * handle full, aligned, BM_BLOCK_SIZE (4K) blocks */
1309         if (unlikely(esector < BM_SECT_PER_BIT-1))
1310                 return;
1311         if (unlikely(esector == (nr_sectors-1)))
1312                 ebnr = lbnr;
1313         else
1314                 ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
1315         sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
1316
1317         if (sbnr > ebnr)
1318                 return;
1319
1320         /*
1321          * ok, (capacity & 7) != 0 sometimes, but who cares...
1322          * we count rs_{total,left} in bits, not sectors.
1323          */
1324         spin_lock_irq(&device->al_lock);
1325         count = drbd_bm_count_bits(device, sbnr, ebnr);
1326         if (count) {
1327                 device->rs_failed += count;
1328
1329                 if (get_ldev(device)) {
1330                         drbd_try_clear_on_disk_bm(device, sector, count, false);
1331                         put_ldev(device);
1332                 }
1333
1334                 /* just wake_up unconditional now, various lc_chaged(),
1335                  * lc_put() in drbd_try_clear_on_disk_bm(). */
1336                 wake_up = 1;
1337         }
1338         spin_unlock_irq(&device->al_lock);
1339         if (wake_up)
1340                 wake_up(&device->al_wait);
1341 }