drivers/block/drbd/drbd

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This source file includes following definitions.
drbd_md_get_buffer
drbd_md_put_buffer
wait_until_done_or_force_detached
_drbd_md_sync_page_io
drbd_md_sync_page_io
find_active_resync_extent
_al_get
drbd_al_begin_io_fastpath
drbd_al_begin_io_prepare
al_extent_to_bm_page
al_tr_number_to_on_disk_sector
__al_write_transaction
al_write_transaction
drbd_al_begin_io_commit
drbd_al_begin_io
drbd_al_begin_io_nonblock
drbd_al_complete_io
_try_lc_del
drbd_al_shrink
drbd_al_initialize
update_rs_extent
drbd_advance_rs_marks
lazy_bitmap_update_due
maybe_schedule_on_disk_bitmap_update
update_sync_bits
plausible_request_size
__drbd_change_sync
_bme_get
_is_in_al
drbd_rs_begin_io
drbd_try_rs_begin_io
drbd_rs_complete_io
drbd_rs_cancel_all
drbd_rs_del_all
   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3    drbd_actlog.c
   4 
   5    This file is part of DRBD by Philipp Reisner and Lars Ellenberg.
   6 
   7    Copyright (C) 2003-2008, LINBIT Information Technologies GmbH.
   8    Copyright (C) 2003-2008, Philipp Reisner <philipp.reisner@linbit.com>.
   9    Copyright (C) 2003-2008, Lars Ellenberg <lars.ellenberg@linbit.com>.
  10 
  11 
  12  */
  13 
  14 #include <linux/slab.h>
  15 #include <linux/crc32c.h>
  16 #include <linux/drbd.h>
  17 #include <linux/drbd_limits.h>
  18 #include "drbd_int.h"
  19 
  20 
  21 enum al_transaction_types {
  22         AL_TR_UPDATE = 0,
  23         AL_TR_INITIALIZED = 0xffff
  24 };
  25 /* all fields on disc in big endian */
  26 struct __packed al_transaction_on_disk {
  27         /* don't we all like magic */
  28         __be32  magic;
  29 
  30         /* to identify the most recent transaction block
  31          * in the on disk ring buffer */
  32         __be32  tr_number;
  33 
  34         /* checksum on the full 4k block, with this field set to 0. */
  35         __be32  crc32c;
  36 
  37         /* type of transaction, special transaction types like:
  38          * purge-all, set-all-idle, set-all-active, ... to-be-defined
  39          * see also enum al_transaction_types */
  40         __be16  transaction_type;
  41 
  42         /* we currently allow only a few thousand extents,
  43          * so 16bit will be enough for the slot number. */
  44 
  45         /* how many updates in this transaction */
  46         __be16  n_updates;
  47 
  48         /* maximum slot number, "al-extents" in drbd.conf speak.
  49          * Having this in each transaction should make reconfiguration
  50          * of that parameter easier. */
  51         __be16  context_size;
  52 
  53         /* slot number the context starts with */
  54         __be16  context_start_slot_nr;
  55 
  56         /* Some reserved bytes.  Expected usage is a 64bit counter of
  57          * sectors-written since device creation, and other data generation tag
  58          * supporting usage */
  59         __be32  __reserved[4];
  60 
  61         /* --- 36 byte used --- */
  62 
  63         /* Reserve space for up to AL_UPDATES_PER_TRANSACTION changes
  64          * in one transaction, then use the remaining byte in the 4k block for
  65          * context information.  "Flexible" number of updates per transaction
  66          * does not help, as we have to account for the case when all update
  67          * slots are used anyways, so it would only complicate code without
  68          * additional benefit.
  69          */
  70         __be16  update_slot_nr[AL_UPDATES_PER_TRANSACTION];
  71 
  72         /* but the extent number is 32bit, which at an extent size of 4 MiB
  73          * allows to cover device sizes of up to 2**54 Byte (16 PiB) */
  74         __be32  update_extent_nr[AL_UPDATES_PER_TRANSACTION];
  75 
  76         /* --- 420 bytes used (36 + 64*6) --- */
  77 
  78         /* 4096 - 420 = 3676 = 919 * 4 */
  79         __be32  context[AL_CONTEXT_PER_TRANSACTION];
  80 };
  81 
  82 void *drbd_md_get_buffer(struct drbd_device *device, const char *intent)
  83 {
  84         int r;
  85 
  86         wait_event(device->misc_wait,
  87                    (r = atomic_cmpxchg(&device->md_io.in_use, 0, 1)) == 0 ||
  88                    device->state.disk <= D_FAILED);
  89 
  90         if (r)
  91                 return NULL;
  92 
  93         device->md_io.current_use = intent;
  94         device->md_io.start_jif = jiffies;
  95         device->md_io.submit_jif = device->md_io.start_jif - 1;
  96         return page_address(device->md_io.page);
  97 }
  98 
  99 void drbd_md_put_buffer(struct drbd_device *device)
 100 {
 101         if (atomic_dec_and_test(&device->md_io.in_use))
 102                 wake_up(&device->misc_wait);
 103 }
 104 
 105 void wait_until_done_or_force_detached(struct drbd_device *device, struct drbd_backing_dev *bdev,
 106                                      unsigned int *done)
 107 {
 108         long dt;
 109 
 110         rcu_read_lock();
 111         dt = rcu_dereference(bdev->disk_conf)->disk_timeout;
 112         rcu_read_unlock();
 113         dt = dt * HZ / 10;
 114         if (dt == 0)
 115                 dt = MAX_SCHEDULE_TIMEOUT;
 116 
 117         dt = wait_event_timeout(device->misc_wait,
 118                         *done || test_bit(FORCE_DETACH, &device->flags), dt);
 119         if (dt == 0) {
 120                 drbd_err(device, "meta-data IO operation timed out\n");
 121                 drbd_chk_io_error(device, 1, DRBD_FORCE_DETACH);
 122         }
 123 }
 124 
 125 static int _drbd_md_sync_page_io(struct drbd_device *device,
 126                                  struct drbd_backing_dev *bdev,
 127                                  sector_t sector, int op)
 128 {
 129         struct bio *bio;
 130         /* we do all our meta data IO in aligned 4k blocks. */
 131         const int size = 4096;
 132         int err, op_flags = 0;
 133 
 134         device->md_io.done = 0;
 135         device->md_io.error = -ENODEV;
 136 
 137         if ((op == REQ_OP_WRITE) && !test_bit(MD_NO_FUA, &device->flags))
 138                 op_flags |= REQ_FUA | REQ_PREFLUSH;
 139         op_flags |= REQ_SYNC;
 140 
 141         bio = bio_alloc_drbd(GFP_NOIO);
 142         bio_set_dev(bio, bdev->md_bdev);
 143         bio->bi_iter.bi_sector = sector;
 144         err = -EIO;
 145         if (bio_add_page(bio, device->md_io.page, size, 0) != size)
 146                 goto out;
 147         bio->bi_private = device;
 148         bio->bi_end_io = drbd_md_endio;
 149         bio_set_op_attrs(bio, op, op_flags);
 150 
 151         if (op != REQ_OP_WRITE && device->state.disk == D_DISKLESS && device->ldev == NULL)
 152                 /* special case, drbd_md_read() during drbd_adm_attach(): no get_ldev */
 153                 ;
 154         else if (!get_ldev_if_state(device, D_ATTACHING)) {
 155                 /* Corresponding put_ldev in drbd_md_endio() */
 156                 drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in _drbd_md_sync_page_io()\n");
 157                 err = -ENODEV;
 158                 goto out;
 159         }
 160 
 161         bio_get(bio); /* one bio_put() is in the completion handler */
 162         atomic_inc(&device->md_io.in_use); /* drbd_md_put_buffer() is in the completion handler */
 163         device->md_io.submit_jif = jiffies;
 164         if (drbd_insert_fault(device, (op == REQ_OP_WRITE) ? DRBD_FAULT_MD_WR : DRBD_FAULT_MD_RD))
 165                 bio_io_error(bio);
 166         else
 167                 submit_bio(bio);
 168         wait_until_done_or_force_detached(device, bdev, &device->md_io.done);
 169         if (!bio->bi_status)
 170                 err = device->md_io.error;
 171 
 172  out:
 173         bio_put(bio);
 174         return err;
 175 }
 176 
 177 int drbd_md_sync_page_io(struct drbd_device *device, struct drbd_backing_dev *bdev,
 178                          sector_t sector, int op)
 179 {
 180         int err;
 181         D_ASSERT(device, atomic_read(&device->md_io.in_use) == 1);
 182 
 183         BUG_ON(!bdev->md_bdev);
 184 
 185         dynamic_drbd_dbg(device, "meta_data io: %s [%d]:%s(,%llus,%s) %pS\n",
 186              current->comm, current->pid, __func__,
 187              (unsigned long long)sector, (op == REQ_OP_WRITE) ? "WRITE" : "READ",
 188              (void*)_RET_IP_ );
 189 
 190         if (sector < drbd_md_first_sector(bdev) ||
 191             sector + 7 > drbd_md_last_sector(bdev))
 192                 drbd_alert(device, "%s [%d]:%s(,%llus,%s) out of range md access!\n",
 193                      current->comm, current->pid, __func__,
 194                      (unsigned long long)sector,
 195                      (op == REQ_OP_WRITE) ? "WRITE" : "READ");
 196 
 197         err = _drbd_md_sync_page_io(device, bdev, sector, op);
 198         if (err) {
 199                 drbd_err(device, "drbd_md_sync_page_io(,%llus,%s) failed with error %d\n",
 200                     (unsigned long long)sector,
 201                     (op == REQ_OP_WRITE) ? "WRITE" : "READ", err);
 202         }
 203         return err;
 204 }
 205 
 206 static struct bm_extent *find_active_resync_extent(struct drbd_device *device, unsigned int enr)
 207 {
 208         struct lc_element *tmp;
 209         tmp = lc_find(device->resync, enr/AL_EXT_PER_BM_SECT);
 210         if (unlikely(tmp != NULL)) {
 211                 struct bm_extent  *bm_ext = lc_entry(tmp, struct bm_extent, lce);
 212                 if (test_bit(BME_NO_WRITES, &bm_ext->flags))
 213                         return bm_ext;
 214         }
 215         return NULL;
 216 }
 217 
 218 static struct lc_element *_al_get(struct drbd_device *device, unsigned int enr, bool nonblock)
 219 {
 220         struct lc_element *al_ext;
 221         struct bm_extent *bm_ext;
 222         int wake;
 223 
 224         spin_lock_irq(&device->al_lock);
 225         bm_ext = find_active_resync_extent(device, enr);
 226         if (bm_ext) {
 227                 wake = !test_and_set_bit(BME_PRIORITY, &bm_ext->flags);
 228                 spin_unlock_irq(&device->al_lock);
 229                 if (wake)
 230                         wake_up(&device->al_wait);
 231                 return NULL;
 232         }
 233         if (nonblock)
 234                 al_ext = lc_try_get(device->act_log, enr);
 235         else
 236                 al_ext = lc_get(device->act_log, enr);
 237         spin_unlock_irq(&device->al_lock);
 238         return al_ext;
 239 }
 240 
 241 bool drbd_al_begin_io_fastpath(struct drbd_device *device, struct drbd_interval *i)
 242 {
 243         /* for bios crossing activity log extent boundaries,
 244          * we may need to activate two extents in one go */
 245         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 246         unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 247 
 248         D_ASSERT(device, first <= last);
 249         D_ASSERT(device, atomic_read(&device->local_cnt) > 0);
 250 
 251         /* FIXME figure out a fast path for bios crossing AL extent boundaries */
 252         if (first != last)
 253                 return false;
 254 
 255         return _al_get(device, first, true);
 256 }
 257 
 258 bool drbd_al_begin_io_prepare(struct drbd_device *device, struct drbd_interval *i)
 259 {
 260         /* for bios crossing activity log extent boundaries,
 261          * we may need to activate two extents in one go */
 262         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 263         unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 264         unsigned enr;
 265         bool need_transaction = false;
 266 
 267         D_ASSERT(device, first <= last);
 268         D_ASSERT(device, atomic_read(&device->local_cnt) > 0);
 269 
 270         for (enr = first; enr <= last; enr++) {
 271                 struct lc_element *al_ext;
 272                 wait_event(device->al_wait,
 273                                 (al_ext = _al_get(device, enr, false)) != NULL);
 274                 if (al_ext->lc_number != enr)
 275                         need_transaction = true;
 276         }
 277         return need_transaction;
 278 }
 279 
 280 #if (PAGE_SHIFT + 3) < (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT)
 281 /* Currently BM_BLOCK_SHIFT, BM_EXT_SHIFT and AL_EXTENT_SHIFT
 282  * are still coupled, or assume too much about their relation.
 283  * Code below will not work if this is violated.
 284  * Will be cleaned up with some followup patch.
 285  */
 286 # error FIXME
 287 #endif
 288 
 289 static unsigned int al_extent_to_bm_page(unsigned int al_enr)
 290 {
 291         return al_enr >>
 292                 /* bit to page */
 293                 ((PAGE_SHIFT + 3) -
 294                 /* al extent number to bit */
 295                  (AL_EXTENT_SHIFT - BM_BLOCK_SHIFT));
 296 }
 297 
 298 static sector_t al_tr_number_to_on_disk_sector(struct drbd_device *device)
 299 {
 300         const unsigned int stripes = device->ldev->md.al_stripes;
 301         const unsigned int stripe_size_4kB = device->ldev->md.al_stripe_size_4k;
 302 
 303         /* transaction number, modulo on-disk ring buffer wrap around */
 304         unsigned int t = device->al_tr_number % (device->ldev->md.al_size_4k);
 305 
 306         /* ... to aligned 4k on disk block */
 307         t = ((t % stripes) * stripe_size_4kB) + t/stripes;
 308 
 309         /* ... to 512 byte sector in activity log */
 310         t *= 8;
 311 
 312         /* ... plus offset to the on disk position */
 313         return device->ldev->md.md_offset + device->ldev->md.al_offset + t;
 314 }
 315 
 316 static int __al_write_transaction(struct drbd_device *device, struct al_transaction_on_disk *buffer)
 317 {
 318         struct lc_element *e;
 319         sector_t sector;
 320         int i, mx;
 321         unsigned extent_nr;
 322         unsigned crc = 0;
 323         int err = 0;
 324 
 325         memset(buffer, 0, sizeof(*buffer));
 326         buffer->magic = cpu_to_be32(DRBD_AL_MAGIC);
 327         buffer->tr_number = cpu_to_be32(device->al_tr_number);
 328 
 329         i = 0;
 330 
 331         drbd_bm_reset_al_hints(device);
 332 
 333         /* Even though no one can start to change this list
 334          * once we set the LC_LOCKED -- from drbd_al_begin_io(),
 335          * lc_try_lock_for_transaction() --, someone may still
 336          * be in the process of changing it. */
 337         spin_lock_irq(&device->al_lock);
 338         list_for_each_entry(e, &device->act_log->to_be_changed, list) {
 339                 if (i == AL_UPDATES_PER_TRANSACTION) {
 340                         i++;
 341                         break;
 342                 }
 343                 buffer->update_slot_nr[i] = cpu_to_be16(e->lc_index);
 344                 buffer->update_extent_nr[i] = cpu_to_be32(e->lc_new_number);
 345                 if (e->lc_number != LC_FREE)
 346                         drbd_bm_mark_for_writeout(device,
 347                                         al_extent_to_bm_page(e->lc_number));
 348                 i++;
 349         }
 350         spin_unlock_irq(&device->al_lock);
 351         BUG_ON(i > AL_UPDATES_PER_TRANSACTION);
 352 
 353         buffer->n_updates = cpu_to_be16(i);
 354         for ( ; i < AL_UPDATES_PER_TRANSACTION; i++) {
 355                 buffer->update_slot_nr[i] = cpu_to_be16(-1);
 356                 buffer->update_extent_nr[i] = cpu_to_be32(LC_FREE);
 357         }
 358 
 359         buffer->context_size = cpu_to_be16(device->act_log->nr_elements);
 360         buffer->context_start_slot_nr = cpu_to_be16(device->al_tr_cycle);
 361 
 362         mx = min_t(int, AL_CONTEXT_PER_TRANSACTION,
 363                    device->act_log->nr_elements - device->al_tr_cycle);
 364         for (i = 0; i < mx; i++) {
 365                 unsigned idx = device->al_tr_cycle + i;
 366                 extent_nr = lc_element_by_index(device->act_log, idx)->lc_number;
 367                 buffer->context[i] = cpu_to_be32(extent_nr);
 368         }
 369         for (; i < AL_CONTEXT_PER_TRANSACTION; i++)
 370                 buffer->context[i] = cpu_to_be32(LC_FREE);
 371 
 372         device->al_tr_cycle += AL_CONTEXT_PER_TRANSACTION;
 373         if (device->al_tr_cycle >= device->act_log->nr_elements)
 374                 device->al_tr_cycle = 0;
 375 
 376         sector = al_tr_number_to_on_disk_sector(device);
 377 
 378         crc = crc32c(0, buffer, 4096);
 379         buffer->crc32c = cpu_to_be32(crc);
 380 
 381         if (drbd_bm_write_hinted(device))
 382                 err = -EIO;
 383         else {
 384                 bool write_al_updates;
 385                 rcu_read_lock();
 386                 write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
 387                 rcu_read_unlock();
 388                 if (write_al_updates) {
 389                         if (drbd_md_sync_page_io(device, device->ldev, sector, WRITE)) {
 390                                 err = -EIO;
 391                                 drbd_chk_io_error(device, 1, DRBD_META_IO_ERROR);
 392                         } else {
 393                                 device->al_tr_number++;
 394                                 device->al_writ_cnt++;
 395                         }
 396                 }
 397         }
 398 
 399         return err;
 400 }
 401 
 402 static int al_write_transaction(struct drbd_device *device)
 403 {
 404         struct al_transaction_on_disk *buffer;
 405         int err;
 406 
 407         if (!get_ldev(device)) {
 408                 drbd_err(device, "disk is %s, cannot start al transaction\n",
 409                         drbd_disk_str(device->state.disk));
 410                 return -EIO;
 411         }
 412 
 413         /* The bitmap write may have failed, causing a state change. */
 414         if (device->state.disk < D_INCONSISTENT) {
 415                 drbd_err(device,
 416                         "disk is %s, cannot write al transaction\n",
 417                         drbd_disk_str(device->state.disk));
 418                 put_ldev(device);
 419                 return -EIO;
 420         }
 421 
 422         /* protects md_io_buffer, al_tr_cycle, ... */
 423         buffer = drbd_md_get_buffer(device, __func__);
 424         if (!buffer) {
 425                 drbd_err(device, "disk failed while waiting for md_io buffer\n");
 426                 put_ldev(device);
 427                 return -ENODEV;
 428         }
 429 
 430         err = __al_write_transaction(device, buffer);
 431 
 432         drbd_md_put_buffer(device);
 433         put_ldev(device);
 434 
 435         return err;
 436 }
 437 
 438 
 439 void drbd_al_begin_io_commit(struct drbd_device *device)
 440 {
 441         bool locked = false;
 442 
 443         /* Serialize multiple transactions.
 444          * This uses test_and_set_bit, memory barrier is implicit.
 445          */
 446         wait_event(device->al_wait,
 447                         device->act_log->pending_changes == 0 ||
 448                         (locked = lc_try_lock_for_transaction(device->act_log)));
 449 
 450         if (locked) {
 451                 /* Double check: it may have been committed by someone else,
 452                  * while we have been waiting for the lock. */
 453                 if (device->act_log->pending_changes) {
 454                         bool write_al_updates;
 455 
 456                         rcu_read_lock();
 457                         write_al_updates = rcu_dereference(device->ldev->disk_conf)->al_updates;
 458                         rcu_read_unlock();
 459 
 460                         if (write_al_updates)
 461                                 al_write_transaction(device);
 462                         spin_lock_irq(&device->al_lock);
 463                         /* FIXME
 464                         if (err)
 465                                 we need an "lc_cancel" here;
 466                         */
 467                         lc_committed(device->act_log);
 468                         spin_unlock_irq(&device->al_lock);
 469                 }
 470                 lc_unlock(device->act_log);
 471                 wake_up(&device->al_wait);
 472         }
 473 }
 474 
 475 /*
 476  * @delegate:   delegate activity log I/O to the worker thread
 477  */
 478 void drbd_al_begin_io(struct drbd_device *device, struct drbd_interval *i)
 479 {
 480         if (drbd_al_begin_io_prepare(device, i))
 481                 drbd_al_begin_io_commit(device);
 482 }
 483 
 484 int drbd_al_begin_io_nonblock(struct drbd_device *device, struct drbd_interval *i)
 485 {
 486         struct lru_cache *al = device->act_log;
 487         /* for bios crossing activity log extent boundaries,
 488          * we may need to activate two extents in one go */
 489         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 490         unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 491         unsigned nr_al_extents;
 492         unsigned available_update_slots;
 493         unsigned enr;
 494 
 495         D_ASSERT(device, first <= last);
 496 
 497         nr_al_extents = 1 + last - first; /* worst case: all touched extends are cold. */
 498         available_update_slots = min(al->nr_elements - al->used,
 499                                 al->max_pending_changes - al->pending_changes);
 500 
 501         /* We want all necessary updates for a given request within the same transaction
 502          * We could first check how many updates are *actually* needed,
 503          * and use that instead of the worst-case nr_al_extents */
 504         if (available_update_slots < nr_al_extents) {
 505                 /* Too many activity log extents are currently "hot".
 506                  *
 507                  * If we have accumulated pending changes already,
 508                  * we made progress.
 509                  *
 510                  * If we cannot get even a single pending change through,
 511                  * stop the fast path until we made some progress,
 512                  * or requests to "cold" extents could be starved. */
 513                 if (!al->pending_changes)
 514                         __set_bit(__LC_STARVING, &device->act_log->flags);
 515                 return -ENOBUFS;
 516         }
 517 
 518         /* Is resync active in this area? */
 519         for (enr = first; enr <= last; enr++) {
 520                 struct lc_element *tmp;
 521                 tmp = lc_find(device->resync, enr/AL_EXT_PER_BM_SECT);
 522                 if (unlikely(tmp != NULL)) {
 523                         struct bm_extent  *bm_ext = lc_entry(tmp, struct bm_extent, lce);
 524                         if (test_bit(BME_NO_WRITES, &bm_ext->flags)) {
 525                                 if (!test_and_set_bit(BME_PRIORITY, &bm_ext->flags))
 526                                         return -EBUSY;
 527                                 return -EWOULDBLOCK;
 528                         }
 529                 }
 530         }
 531 
 532         /* Checkout the refcounts.
 533          * Given that we checked for available elements and update slots above,
 534          * this has to be successful. */
 535         for (enr = first; enr <= last; enr++) {
 536                 struct lc_element *al_ext;
 537                 al_ext = lc_get_cumulative(device->act_log, enr);
 538                 if (!al_ext)
 539                         drbd_info(device, "LOGIC BUG for enr=%u\n", enr);
 540         }
 541         return 0;
 542 }
 543 
 544 void drbd_al_complete_io(struct drbd_device *device, struct drbd_interval *i)
 545 {
 546         /* for bios crossing activity log extent boundaries,
 547          * we may need to activate two extents in one go */
 548         unsigned first = i->sector >> (AL_EXTENT_SHIFT-9);
 549         unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9);
 550         unsigned enr;
 551         struct lc_element *extent;
 552         unsigned long flags;
 553 
 554         D_ASSERT(device, first <= last);
 555         spin_lock_irqsave(&device->al_lock, flags);
 556 
 557         for (enr = first; enr <= last; enr++) {
 558                 extent = lc_find(device->act_log, enr);
 559                 if (!extent) {
 560                         drbd_err(device, "al_complete_io() called on inactive extent %u\n", enr);
 561                         continue;
 562                 }
 563                 lc_put(device->act_log, extent);
 564         }
 565         spin_unlock_irqrestore(&device->al_lock, flags);
 566         wake_up(&device->al_wait);
 567 }
 568 
 569 static int _try_lc_del(struct drbd_device *device, struct lc_element *al_ext)
 570 {
 571         int rv;
 572 
 573         spin_lock_irq(&device->al_lock);
 574         rv = (al_ext->refcnt == 0);
 575         if (likely(rv))
 576                 lc_del(device->act_log, al_ext);
 577         spin_unlock_irq(&device->al_lock);
 578 
 579         return rv;
 580 }
 581 
 582 /**
 583  * drbd_al_shrink() - Removes all active extents form the activity log
 584  * @device:     DRBD device.
 585  *
 586  * Removes all active extents form the activity log, waiting until
 587  * the reference count of each entry dropped to 0 first, of course.
 588  *
 589  * You need to lock device->act_log with lc_try_lock() / lc_unlock()
 590  */
 591 void drbd_al_shrink(struct drbd_device *device)
 592 {
 593         struct lc_element *al_ext;
 594         int i;
 595 
 596         D_ASSERT(device, test_bit(__LC_LOCKED, &device->act_log->flags));
 597 
 598         for (i = 0; i < device->act_log->nr_elements; i++) {
 599                 al_ext = lc_element_by_index(device->act_log, i);
 600                 if (al_ext->lc_number == LC_FREE)
 601                         continue;
 602                 wait_event(device->al_wait, _try_lc_del(device, al_ext));
 603         }
 604 
 605         wake_up(&device->al_wait);
 606 }
 607 
 608 int drbd_al_initialize(struct drbd_device *device, void *buffer)
 609 {
 610         struct al_transaction_on_disk *al = buffer;
 611         struct drbd_md *md = &device->ldev->md;
 612         int al_size_4k = md->al_stripes * md->al_stripe_size_4k;
 613         int i;
 614 
 615         __al_write_transaction(device, al);
 616         /* There may or may not have been a pending transaction. */
 617         spin_lock_irq(&device->al_lock);
 618         lc_committed(device->act_log);
 619         spin_unlock_irq(&device->al_lock);
 620 
 621         /* The rest of the transactions will have an empty "updates" list, and
 622          * are written out only to provide the context, and to initialize the
 623          * on-disk ring buffer. */
 624         for (i = 1; i < al_size_4k; i++) {
 625                 int err = __al_write_transaction(device, al);
 626                 if (err)
 627                         return err;
 628         }
 629         return 0;
 630 }
 631 
 632 static const char *drbd_change_sync_fname[] = {
 633         [RECORD_RS_FAILED] = "drbd_rs_failed_io",
 634         [SET_IN_SYNC] = "drbd_set_in_sync",
 635         [SET_OUT_OF_SYNC] = "drbd_set_out_of_sync"
 636 };
 637 
 638 /* ATTENTION. The AL's extents are 4MB each, while the extents in the
 639  * resync LRU-cache are 16MB each.
 640  * The caller of this function has to hold an get_ldev() reference.
 641  *
 642  * Adjusts the caching members ->rs_left (success) or ->rs_failed (!success),
 643  * potentially pulling in (and recounting the corresponding bits)
 644  * this resync extent into the resync extent lru cache.
 645  *
 646  * Returns whether all bits have been cleared for this resync extent,
 647  * precisely: (rs_left <= rs_failed)
 648  *
 649  * TODO will be obsoleted once we have a caching lru of the on disk bitmap
 650  */
 651 static bool update_rs_extent(struct drbd_device *device,
 652                 unsigned int enr, int count,
 653                 enum update_sync_bits_mode mode)
 654 {
 655         struct lc_element *e;
 656 
 657         D_ASSERT(device, atomic_read(&device->local_cnt));
 658 
 659         /* When setting out-of-sync bits,
 660          * we don't need it cached (lc_find).
 661          * But if it is present in the cache,
 662          * we should update the cached bit count.
 663          * Otherwise, that extent should be in the resync extent lru cache
 664          * already -- or we want to pull it in if necessary -- (lc_get),
 665          * then update and check rs_left and rs_failed. */
 666         if (mode == SET_OUT_OF_SYNC)
 667                 e = lc_find(device->resync, enr);
 668         else
 669                 e = lc_get(device->resync, enr);
 670         if (e) {
 671                 struct bm_extent *ext = lc_entry(e, struct bm_extent, lce);
 672                 if (ext->lce.lc_number == enr) {
 673                         if (mode == SET_IN_SYNC)
 674                                 ext->rs_left -= count;
 675                         else if (mode == SET_OUT_OF_SYNC)
 676                                 ext->rs_left += count;
 677                         else
 678                                 ext->rs_failed += count;
 679                         if (ext->rs_left < ext->rs_failed) {
 680                                 drbd_warn(device, "BAD! enr=%u rs_left=%d "
 681                                     "rs_failed=%d count=%d cstate=%s\n",
 682                                      ext->lce.lc_number, ext->rs_left,
 683                                      ext->rs_failed, count,
 684                                      drbd_conn_str(device->state.conn));
 685 
 686                                 /* We don't expect to be able to clear more bits
 687                                  * than have been set when we originally counted
 688                                  * the set bits to cache that value in ext->rs_left.
 689                                  * Whatever the reason (disconnect during resync,
 690                                  * delayed local completion of an application write),
 691                                  * try to fix it up by recounting here. */
 692                                 ext->rs_left = drbd_bm_e_weight(device, enr);
 693                         }
 694                 } else {
 695                         /* Normally this element should be in the cache,
 696                          * since drbd_rs_begin_io() pulled it already in.
 697                          *
 698                          * But maybe an application write finished, and we set
 699                          * something outside the resync lru_cache in sync.
 700                          */
 701                         int rs_left = drbd_bm_e_weight(device, enr);
 702                         if (ext->flags != 0) {
 703                                 drbd_warn(device, "changing resync lce: %d[%u;%02lx]"
 704                                      " -> %d[%u;00]\n",
 705                                      ext->lce.lc_number, ext->rs_left,
 706                                      ext->flags, enr, rs_left);
 707                                 ext->flags = 0;
 708                         }
 709                         if (ext->rs_failed) {
 710                                 drbd_warn(device, "Kicking resync_lru element enr=%u "
 711                                      "out with rs_failed=%d\n",
 712                                      ext->lce.lc_number, ext->rs_failed);
 713                         }
 714                         ext->rs_left = rs_left;
 715                         ext->rs_failed = (mode == RECORD_RS_FAILED) ? count : 0;
 716                         /* we don't keep a persistent log of the resync lru,
 717                          * we can commit any change right away. */
 718                         lc_committed(device->resync);
 719                 }
 720                 if (mode != SET_OUT_OF_SYNC)
 721                         lc_put(device->resync, &ext->lce);
 722                 /* no race, we are within the al_lock! */
 723 
 724                 if (ext->rs_left <= ext->rs_failed) {
 725                         ext->rs_failed = 0;
 726                         return true;
 727                 }
 728         } else if (mode != SET_OUT_OF_SYNC) {
 729                 /* be quiet if lc_find() did not find it. */
 730                 drbd_err(device, "lc_get() failed! locked=%d/%d flags=%lu\n",
 731                     device->resync_locked,
 732                     device->resync->nr_elements,
 733                     device->resync->flags);
 734         }
 735         return false;
 736 }
 737 
 738 void drbd_advance_rs_marks(struct drbd_device *device, unsigned long still_to_go)
 739 {
 740         unsigned long now = jiffies;
 741         unsigned long last = device->rs_mark_time[device->rs_last_mark];
 742         int next = (device->rs_last_mark + 1) % DRBD_SYNC_MARKS;
 743         if (time_after_eq(now, last + DRBD_SYNC_MARK_STEP)) {
 744                 if (device->rs_mark_left[device->rs_last_mark] != still_to_go &&
 745                     device->state.conn != C_PAUSED_SYNC_T &&
 746                     device->state.conn != C_PAUSED_SYNC_S) {
 747                         device->rs_mark_time[next] = now;
 748                         device->rs_mark_left[next] = still_to_go;
 749                         device->rs_last_mark = next;
 750                 }
 751         }
 752 }
 753 
 754 /* It is called lazy update, so don't do write-out too often. */
 755 static bool lazy_bitmap_update_due(struct drbd_device *device)
 756 {
 757         return time_after(jiffies, device->rs_last_bcast + 2*HZ);
 758 }
 759 
 760 static void maybe_schedule_on_disk_bitmap_update(struct drbd_device *device, bool rs_done)
 761 {
 762         if (rs_done) {
 763                 struct drbd_connection *connection = first_peer_device(device)->connection;
 764                 if (connection->agreed_pro_version <= 95 ||
 765                     is_sync_target_state(device->state.conn))
 766                         set_bit(RS_DONE, &device->flags);
 767                         /* and also set RS_PROGRESS below */
 768 
 769                 /* Else: rather wait for explicit notification via receive_state,
 770                  * to avoid uuids-rotated-too-fast causing full resync
 771                  * in next handshake, in case the replication link breaks
 772                  * at the most unfortunate time... */
 773         } else if (!lazy_bitmap_update_due(device))
 774                 return;
 775 
 776         drbd_device_post_work(device, RS_PROGRESS);
 777 }
 778 
 779 static int update_sync_bits(struct drbd_device *device,
 780                 unsigned long sbnr, unsigned long ebnr,
 781                 enum update_sync_bits_mode mode)
 782 {
 783         /*
 784          * We keep a count of set bits per resync-extent in the ->rs_left
 785          * caching member, so we need to loop and work within the resync extent
 786          * alignment. Typically this loop will execute exactly once.
 787          */
 788         unsigned long flags;
 789         unsigned long count = 0;
 790         unsigned int cleared = 0;
 791         while (sbnr <= ebnr) {
 792                 /* set temporary boundary bit number to last bit number within
 793                  * the resync extent of the current start bit number,
 794                  * but cap at provided end bit number */
 795                 unsigned long tbnr = min(ebnr, sbnr | BM_BLOCKS_PER_BM_EXT_MASK);
 796                 unsigned long c;
 797 
 798                 if (mode == RECORD_RS_FAILED)
 799                         /* Only called from drbd_rs_failed_io(), bits
 800                          * supposedly still set.  Recount, maybe some
 801                          * of the bits have been successfully cleared
 802                          * by application IO meanwhile.
 803                          */
 804                         c = drbd_bm_count_bits(device, sbnr, tbnr);
 805                 else if (mode == SET_IN_SYNC)
 806                         c = drbd_bm_clear_bits(device, sbnr, tbnr);
 807                 else /* if (mode == SET_OUT_OF_SYNC) */
 808                         c = drbd_bm_set_bits(device, sbnr, tbnr);
 809 
 810                 if (c) {
 811                         spin_lock_irqsave(&device->al_lock, flags);
 812                         cleared += update_rs_extent(device, BM_BIT_TO_EXT(sbnr), c, mode);
 813                         spin_unlock_irqrestore(&device->al_lock, flags);
 814                         count += c;
 815                 }
 816                 sbnr = tbnr + 1;
 817         }
 818         if (count) {
 819                 if (mode == SET_IN_SYNC) {
 820                         unsigned long still_to_go = drbd_bm_total_weight(device);
 821                         bool rs_is_done = (still_to_go <= device->rs_failed);
 822                         drbd_advance_rs_marks(device, still_to_go);
 823                         if (cleared || rs_is_done)
 824                                 maybe_schedule_on_disk_bitmap_update(device, rs_is_done);
 825                 } else if (mode == RECORD_RS_FAILED)
 826                         device->rs_failed += count;
 827                 wake_up(&device->al_wait);
 828         }
 829         return count;
 830 }
 831 
 832 static bool plausible_request_size(int size)
 833 {
 834         return size > 0
 835                 && size <= DRBD_MAX_BATCH_BIO_SIZE
 836                 && IS_ALIGNED(size, 512);
 837 }
 838 
 839 /* clear the bit corresponding to the piece of storage in question:
 840  * size byte of data starting from sector.  Only clear a bits of the affected
 841  * one ore more _aligned_ BM_BLOCK_SIZE blocks.
 842  *
 843  * called by worker on C_SYNC_TARGET and receiver on SyncSource.
 844  *
 845  */
 846 int __drbd_change_sync(struct drbd_device *device, sector_t sector, int size,
 847                 enum update_sync_bits_mode mode)
 848 {
 849         /* Is called from worker and receiver context _only_ */
 850         unsigned long sbnr, ebnr, lbnr;
 851         unsigned long count = 0;
 852         sector_t esector, nr_sectors;
 853 
 854         /* This would be an empty REQ_PREFLUSH, be silent. */
 855         if ((mode == SET_OUT_OF_SYNC) && size == 0)
 856                 return 0;
 857 
 858         if (!plausible_request_size(size)) {
 859                 drbd_err(device, "%s: sector=%llus size=%d nonsense!\n",
 860                                 drbd_change_sync_fname[mode],
 861                                 (unsigned long long)sector, size);
 862                 return 0;
 863         }
 864 
 865         if (!get_ldev(device))
 866                 return 0; /* no disk, no metadata, no bitmap to manipulate bits in */
 867 
 868         nr_sectors = drbd_get_capacity(device->this_bdev);
 869         esector = sector + (size >> 9) - 1;
 870 
 871         if (!expect(sector < nr_sectors))
 872                 goto out;
 873         if (!expect(esector < nr_sectors))
 874                 esector = nr_sectors - 1;
 875 
 876         lbnr = BM_SECT_TO_BIT(nr_sectors-1);
 877 
 878         if (mode == SET_IN_SYNC) {
 879                 /* Round up start sector, round down end sector.  We make sure
 880                  * we only clear full, aligned, BM_BLOCK_SIZE blocks. */
 881                 if (unlikely(esector < BM_SECT_PER_BIT-1))
 882                         goto out;
 883                 if (unlikely(esector == (nr_sectors-1)))
 884                         ebnr = lbnr;
 885                 else
 886                         ebnr = BM_SECT_TO_BIT(esector - (BM_SECT_PER_BIT-1));
 887                 sbnr = BM_SECT_TO_BIT(sector + BM_SECT_PER_BIT-1);
 888         } else {
 889                 /* We set it out of sync, or record resync failure.
 890                  * Should not round anything here. */
 891                 sbnr = BM_SECT_TO_BIT(sector);
 892                 ebnr = BM_SECT_TO_BIT(esector);
 893         }
 894 
 895         count = update_sync_bits(device, sbnr, ebnr, mode);
 896 out:
 897         put_ldev(device);
 898         return count;
 899 }
 900 
 901 static
 902 struct bm_extent *_bme_get(struct drbd_device *device, unsigned int enr)
 903 {
 904         struct lc_element *e;
 905         struct bm_extent *bm_ext;
 906         int wakeup = 0;
 907         unsigned long rs_flags;
 908 
 909         spin_lock_irq(&device->al_lock);
 910         if (device->resync_locked > device->resync->nr_elements/2) {
 911                 spin_unlock_irq(&device->al_lock);
 912                 return NULL;
 913         }
 914         e = lc_get(device->resync, enr);
 915         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
 916         if (bm_ext) {
 917                 if (bm_ext->lce.lc_number != enr) {
 918                         bm_ext->rs_left = drbd_bm_e_weight(device, enr);
 919                         bm_ext->rs_failed = 0;
 920                         lc_committed(device->resync);
 921                         wakeup = 1;
 922                 }
 923                 if (bm_ext->lce.refcnt == 1)
 924                         device->resync_locked++;
 925                 set_bit(BME_NO_WRITES, &bm_ext->flags);
 926         }
 927         rs_flags = device->resync->flags;
 928         spin_unlock_irq(&device->al_lock);
 929         if (wakeup)
 930                 wake_up(&device->al_wait);
 931 
 932         if (!bm_ext) {
 933                 if (rs_flags & LC_STARVING)
 934                         drbd_warn(device, "Have to wait for element"
 935                              " (resync LRU too small?)\n");
 936                 BUG_ON(rs_flags & LC_LOCKED);
 937         }
 938 
 939         return bm_ext;
 940 }
 941 
 942 static int _is_in_al(struct drbd_device *device, unsigned int enr)
 943 {
 944         int rv;
 945 
 946         spin_lock_irq(&device->al_lock);
 947         rv = lc_is_used(device->act_log, enr);
 948         spin_unlock_irq(&device->al_lock);
 949 
 950         return rv;
 951 }
 952 
 953 /**
 954  * drbd_rs_begin_io() - Gets an extent in the resync LRU cache and sets it to BME_LOCKED
 955  * @device:     DRBD device.
 956  * @sector:     The sector number.
 957  *
 958  * This functions sleeps on al_wait. Returns 0 on success, -EINTR if interrupted.
 959  */
 960 int drbd_rs_begin_io(struct drbd_device *device, sector_t sector)
 961 {
 962         unsigned int enr = BM_SECT_TO_EXT(sector);
 963         struct bm_extent *bm_ext;
 964         int i, sig;
 965         bool sa;
 966 
 967 retry:
 968         sig = wait_event_interruptible(device->al_wait,
 969                         (bm_ext = _bme_get(device, enr)));
 970         if (sig)
 971                 return -EINTR;
 972 
 973         if (test_bit(BME_LOCKED, &bm_ext->flags))
 974                 return 0;
 975 
 976         /* step aside only while we are above c-min-rate; unless disabled. */
 977         sa = drbd_rs_c_min_rate_throttle(device);
 978 
 979         for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
 980                 sig = wait_event_interruptible(device->al_wait,
 981                                                !_is_in_al(device, enr * AL_EXT_PER_BM_SECT + i) ||
 982                                                (sa && test_bit(BME_PRIORITY, &bm_ext->flags)));
 983 
 984                 if (sig || (sa && test_bit(BME_PRIORITY, &bm_ext->flags))) {
 985                         spin_lock_irq(&device->al_lock);
 986                         if (lc_put(device->resync, &bm_ext->lce) == 0) {
 987                                 bm_ext->flags = 0; /* clears BME_NO_WRITES and eventually BME_PRIORITY */
 988                                 device->resync_locked--;
 989                                 wake_up(&device->al_wait);
 990                         }
 991                         spin_unlock_irq(&device->al_lock);
 992                         if (sig)
 993                                 return -EINTR;
 994                         if (schedule_timeout_interruptible(HZ/10))
 995                                 return -EINTR;
 996                         goto retry;
 997                 }
 998         }
 999         set_bit(BME_LOCKED, &bm_ext->flags);
1000         return 0;
1001 }
1002 
1003 /**
1004  * drbd_try_rs_begin_io() - Gets an extent in the resync LRU cache, does not sleep
1005  * @device:     DRBD device.
1006  * @sector:     The sector number.
1007  *
1008  * Gets an extent in the resync LRU cache, sets it to BME_NO_WRITES, then
1009  * tries to set it to BME_LOCKED. Returns 0 upon success, and -EAGAIN
1010  * if there is still application IO going on in this area.
1011  */
1012 int drbd_try_rs_begin_io(struct drbd_device *device, sector_t sector)
1013 {
1014         unsigned int enr = BM_SECT_TO_EXT(sector);
1015         const unsigned int al_enr = enr*AL_EXT_PER_BM_SECT;
1016         struct lc_element *e;
1017         struct bm_extent *bm_ext;
1018         int i;
1019         bool throttle = drbd_rs_should_slow_down(device, sector, true);
1020 
1021         /* If we need to throttle, a half-locked (only marked BME_NO_WRITES,
1022          * not yet BME_LOCKED) extent needs to be kicked out explicitly if we
1023          * need to throttle. There is at most one such half-locked extent,
1024          * which is remembered in resync_wenr. */
1025 
1026         if (throttle && device->resync_wenr != enr)
1027                 return -EAGAIN;
1028 
1029         spin_lock_irq(&device->al_lock);
1030         if (device->resync_wenr != LC_FREE && device->resync_wenr != enr) {
1031                 /* in case you have very heavy scattered io, it may
1032                  * stall the syncer undefined if we give up the ref count
1033                  * when we try again and requeue.
1034                  *
1035                  * if we don't give up the refcount, but the next time
1036                  * we are scheduled this extent has been "synced" by new
1037                  * application writes, we'd miss the lc_put on the
1038                  * extent we keep the refcount on.
1039                  * so we remembered which extent we had to try again, and
1040                  * if the next requested one is something else, we do
1041                  * the lc_put here...
1042                  * we also have to wake_up
1043                  */
1044                 e = lc_find(device->resync, device->resync_wenr);
1045                 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1046                 if (bm_ext) {
1047                         D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1048                         D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1049                         clear_bit(BME_NO_WRITES, &bm_ext->flags);
1050                         device->resync_wenr = LC_FREE;
1051                         if (lc_put(device->resync, &bm_ext->lce) == 0) {
1052                                 bm_ext->flags = 0;
1053                                 device->resync_locked--;
1054                         }
1055                         wake_up(&device->al_wait);
1056                 } else {
1057                         drbd_alert(device, "LOGIC BUG\n");
1058                 }
1059         }
1060         /* TRY. */
1061         e = lc_try_get(device->resync, enr);
1062         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1063         if (bm_ext) {
1064                 if (test_bit(BME_LOCKED, &bm_ext->flags))
1065                         goto proceed;
1066                 if (!test_and_set_bit(BME_NO_WRITES, &bm_ext->flags)) {
1067                         device->resync_locked++;
1068                 } else {
1069                         /* we did set the BME_NO_WRITES,
1070                          * but then could not set BME_LOCKED,
1071                          * so we tried again.
1072                          * drop the extra reference. */
1073                         bm_ext->lce.refcnt--;
1074                         D_ASSERT(device, bm_ext->lce.refcnt > 0);
1075                 }
1076                 goto check_al;
1077         } else {
1078                 /* do we rather want to try later? */
1079                 if (device->resync_locked > device->resync->nr_elements-3)
1080                         goto try_again;
1081                 /* Do or do not. There is no try. -- Yoda */
1082                 e = lc_get(device->resync, enr);
1083                 bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1084                 if (!bm_ext) {
1085                         const unsigned long rs_flags = device->resync->flags;
1086                         if (rs_flags & LC_STARVING)
1087                                 drbd_warn(device, "Have to wait for element"
1088                                      " (resync LRU too small?)\n");
1089                         BUG_ON(rs_flags & LC_LOCKED);
1090                         goto try_again;
1091                 }
1092                 if (bm_ext->lce.lc_number != enr) {
1093                         bm_ext->rs_left = drbd_bm_e_weight(device, enr);
1094                         bm_ext->rs_failed = 0;
1095                         lc_committed(device->resync);
1096                         wake_up(&device->al_wait);
1097                         D_ASSERT(device, test_bit(BME_LOCKED, &bm_ext->flags) == 0);
1098                 }
1099                 set_bit(BME_NO_WRITES, &bm_ext->flags);
1100                 D_ASSERT(device, bm_ext->lce.refcnt == 1);
1101                 device->resync_locked++;
1102                 goto check_al;
1103         }
1104 check_al:
1105         for (i = 0; i < AL_EXT_PER_BM_SECT; i++) {
1106                 if (lc_is_used(device->act_log, al_enr+i))
1107                         goto try_again;
1108         }
1109         set_bit(BME_LOCKED, &bm_ext->flags);
1110 proceed:
1111         device->resync_wenr = LC_FREE;
1112         spin_unlock_irq(&device->al_lock);
1113         return 0;
1114 
1115 try_again:
1116         if (bm_ext) {
1117                 if (throttle) {
1118                         D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1119                         D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1120                         clear_bit(BME_NO_WRITES, &bm_ext->flags);
1121                         device->resync_wenr = LC_FREE;
1122                         if (lc_put(device->resync, &bm_ext->lce) == 0) {
1123                                 bm_ext->flags = 0;
1124                                 device->resync_locked--;
1125                         }
1126                         wake_up(&device->al_wait);
1127                 } else
1128                         device->resync_wenr = enr;
1129         }
1130         spin_unlock_irq(&device->al_lock);
1131         return -EAGAIN;
1132 }
1133 
1134 void drbd_rs_complete_io(struct drbd_device *device, sector_t sector)
1135 {
1136         unsigned int enr = BM_SECT_TO_EXT(sector);
1137         struct lc_element *e;
1138         struct bm_extent *bm_ext;
1139         unsigned long flags;
1140 
1141         spin_lock_irqsave(&device->al_lock, flags);
1142         e = lc_find(device->resync, enr);
1143         bm_ext = e ? lc_entry(e, struct bm_extent, lce) : NULL;
1144         if (!bm_ext) {
1145                 spin_unlock_irqrestore(&device->al_lock, flags);
1146                 if (__ratelimit(&drbd_ratelimit_state))
1147                         drbd_err(device, "drbd_rs_complete_io() called, but extent not found\n");
1148                 return;
1149         }
1150 
1151         if (bm_ext->lce.refcnt == 0) {
1152                 spin_unlock_irqrestore(&device->al_lock, flags);
1153                 drbd_err(device, "drbd_rs_complete_io(,%llu [=%u]) called, "
1154                     "but refcnt is 0!?\n",
1155                     (unsigned long long)sector, enr);
1156                 return;
1157         }
1158 
1159         if (lc_put(device->resync, &bm_ext->lce) == 0) {
1160                 bm_ext->flags = 0; /* clear BME_LOCKED, BME_NO_WRITES and BME_PRIORITY */
1161                 device->resync_locked--;
1162                 wake_up(&device->al_wait);
1163         }
1164 
1165         spin_unlock_irqrestore(&device->al_lock, flags);
1166 }
1167 
1168 /**
1169  * drbd_rs_cancel_all() - Removes all extents from the resync LRU (even BME_LOCKED)
1170  * @device:     DRBD device.
1171  */
1172 void drbd_rs_cancel_all(struct drbd_device *device)
1173 {
1174         spin_lock_irq(&device->al_lock);
1175 
1176         if (get_ldev_if_state(device, D_FAILED)) { /* Makes sure ->resync is there. */
1177                 lc_reset(device->resync);
1178                 put_ldev(device);
1179         }
1180         device->resync_locked = 0;
1181         device->resync_wenr = LC_FREE;
1182         spin_unlock_irq(&device->al_lock);
1183         wake_up(&device->al_wait);
1184 }
1185 
1186 /**
1187  * drbd_rs_del_all() - Gracefully remove all extents from the resync LRU
1188  * @device:     DRBD device.
1189  *
1190  * Returns 0 upon success, -EAGAIN if at least one reference count was
1191  * not zero.
1192  */
1193 int drbd_rs_del_all(struct drbd_device *device)
1194 {
1195         struct lc_element *e;
1196         struct bm_extent *bm_ext;
1197         int i;
1198 
1199         spin_lock_irq(&device->al_lock);
1200 
1201         if (get_ldev_if_state(device, D_FAILED)) {
1202                 /* ok, ->resync is there. */
1203                 for (i = 0; i < device->resync->nr_elements; i++) {
1204                         e = lc_element_by_index(device->resync, i);
1205                         bm_ext = lc_entry(e, struct bm_extent, lce);
1206                         if (bm_ext->lce.lc_number == LC_FREE)
1207                                 continue;
1208                         if (bm_ext->lce.lc_number == device->resync_wenr) {
1209                                 drbd_info(device, "dropping %u in drbd_rs_del_all, apparently"
1210                                      " got 'synced' by application io\n",
1211                                      device->resync_wenr);
1212                                 D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1213                                 D_ASSERT(device, test_bit(BME_NO_WRITES, &bm_ext->flags));
1214                                 clear_bit(BME_NO_WRITES, &bm_ext->flags);
1215                                 device->resync_wenr = LC_FREE;
1216                                 lc_put(device->resync, &bm_ext->lce);
1217                         }
1218                         if (bm_ext->lce.refcnt != 0) {
1219                                 drbd_info(device, "Retrying drbd_rs_del_all() later. "
1220                                      "refcnt=%d\n", bm_ext->lce.refcnt);
1221                                 put_ldev(device);
1222                                 spin_unlock_irq(&device->al_lock);
1223                                 return -EAGAIN;
1224                         }
1225                         D_ASSERT(device, !test_bit(BME_LOCKED, &bm_ext->flags));
1226                         D_ASSERT(device, !test_bit(BME_NO_WRITES, &bm_ext->flags));
1227                         lc_del(device->resync, &bm_ext->lce);
1228                 }
1229                 D_ASSERT(device, device->resync->used == 0);
1230                 put_ldev(device);
1231         }
1232         spin_unlock_irq(&device->al_lock);
1233         wake_up(&device->al_wait);
1234 
1235         return 0;
1236 }
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root/drivers/block/drbd/drbd_actlog.c

DEFINITIONS
