git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/alloc_foreground.c

   1 /*
   2  * Primary bucket allocation code
   3  *
   4  * Copyright 2012 Google, Inc.
   5  *
   6  * Allocation in bcache is done in terms of buckets:
   7  *
   8  * Each bucket has associated an 8 bit gen; this gen corresponds to the gen in
   9  * btree pointers - they must match for the pointer to be considered valid.
  10  *
  11  * Thus (assuming a bucket has no dirty data or metadata in it) we can reuse a
  12  * bucket simply by incrementing its gen.
  13  *
  14  * The gens (along with the priorities; it's really the gens are important but
  15  * the code is named as if it's the priorities) are written in an arbitrary list
  16  * of buckets on disk, with a pointer to them in the journal header.
  17  *
  18  * When we invalidate a bucket, we have to write its new gen to disk and wait
  19  * for that write to complete before we use it - otherwise after a crash we
  20  * could have pointers that appeared to be good but pointed to data that had
  21  * been overwritten.
  22  *
  23  * Since the gens and priorities are all stored contiguously on disk, we can
  24  * batch this up: We fill up the free_inc list with freshly invalidated buckets,
  25  * call prio_write(), and when prio_write() finishes we pull buckets off the
  26  * free_inc list and optionally discard them.
  27  *
  28  * free_inc isn't the only freelist - if it was, we'd often have to sleep while
  29  * priorities and gens were being written before we could allocate. c->free is a
  30  * smaller freelist, and buckets on that list are always ready to be used.
  31  *
  32  * If we've got discards enabled, that happens when a bucket moves from the
  33  * free_inc list to the free list.
  34  *
  35  * It's important to ensure that gens don't wrap around - with respect to
  36  * either the oldest gen in the btree or the gen on disk. This is quite
  37  * difficult to do in practice, but we explicitly guard against it anyways - if
  38  * a bucket is in danger of wrapping around we simply skip invalidating it that
  39  * time around, and we garbage collect or rewrite the priorities sooner than we
  40  * would have otherwise.
  41  *
  42  * bch2_bucket_alloc() allocates a single bucket from a specific device.
  43  *
  44  * bch2_bucket_alloc_set() allocates one or more buckets from different devices
  45  * in a given filesystem.
  46  *
  47  * invalidate_buckets() drives all the processes described above. It's called
  48  * from bch2_bucket_alloc() and a few other places that need to make sure free
  49  * buckets are ready.
  50  *
  51  * invalidate_buckets_(lru|fifo)() find buckets that are available to be
  52  * invalidated, and then invalidate them and stick them on the free_inc list -
  53  * in either lru or fifo order.
  54  */
  55
  56 #include "bcachefs.h"
  57 #include "alloc_background.h"
  58 #include "alloc_foreground.h"
  59 #include "btree_gc.h"
  60 #include "buckets.h"
  61 #include "clock.h"
  62 #include "debug.h"
  63 #include "disk_groups.h"
  64 #include "io.h"
  65
  66 #include <linux/math64.h>
  67 #include <linux/rculist.h>
  68 #include <linux/rcupdate.h>
  69 #include <trace/events/bcachefs.h>
  70
  71 enum bucket_alloc_ret {
  72         ALLOC_SUCCESS,
  73         OPEN_BUCKETS_EMPTY,
  74         FREELIST_EMPTY,         /* Allocator thread not keeping up */
  75 };
  76
  77 /*
  78  * Open buckets represent a bucket that's currently being allocated from.  They
  79  * serve two purposes:
  80  *
  81  *  - They track buckets that have been partially allocated, allowing for
  82  *    sub-bucket sized allocations - they're used by the sector allocator below
  83  *
  84  *  - They provide a reference to the buckets they own that mark and sweep GC
  85  *    can find, until the new allocation has a pointer to it inserted into the
  86  *    btree
  87  *
  88  * When allocating some space with the sector allocator, the allocation comes
  89  * with a reference to an open bucket - the caller is required to put that
  90  * reference _after_ doing the index update that makes its allocation reachable.
  91  */
  92
  93 void __bch2_open_bucket_put(struct bch_fs *c, struct open_bucket *ob)
  94 {
  95         struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev);
  96
  97         percpu_down_read_preempt_disable(&c->usage_lock);
  98         spin_lock(&ob->lock);
  99
 100         bch2_mark_alloc_bucket(c, ca, PTR_BUCKET_NR(ca, &ob->ptr),
 101                                false, gc_pos_alloc(c, ob), 0);
 102         ob->valid = false;
 103
 104         spin_unlock(&ob->lock);
 105         percpu_up_read_preempt_enable(&c->usage_lock);
 106
 107         spin_lock(&c->freelist_lock);
 108         ob->freelist = c->open_buckets_freelist;
 109         c->open_buckets_freelist = ob - c->open_buckets;
 110         c->open_buckets_nr_free++;
 111         spin_unlock(&c->freelist_lock);
 112
 113         closure_wake_up(&c->open_buckets_wait);
 114 }
 115
 116 static struct open_bucket *bch2_open_bucket_alloc(struct bch_fs *c)
 117 {
 118         struct open_bucket *ob;
 119
 120         BUG_ON(!c->open_buckets_freelist || !c->open_buckets_nr_free);
 121
 122         ob = c->open_buckets + c->open_buckets_freelist;
 123         c->open_buckets_freelist = ob->freelist;
 124         atomic_set(&ob->pin, 1);
 125
 126         c->open_buckets_nr_free--;
 127         return ob;
 128 }
 129
 130 static void open_bucket_free_unused(struct bch_fs *c,
 131                                     struct write_point *wp,
 132                                     struct open_bucket *ob)
 133 {
 134         struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev);
 135
 136         BUG_ON(ca->open_buckets_partial_nr >=
 137                ARRAY_SIZE(ca->open_buckets_partial));
 138
 139         if (wp->type == BCH_DATA_USER) {
 140                 spin_lock(&c->freelist_lock);
 141                 ob->on_partial_list = true;
 142                 ca->open_buckets_partial[ca->open_buckets_partial_nr++] =
 143                         ob - c->open_buckets;
 144                 spin_unlock(&c->freelist_lock);
 145
 146                 closure_wake_up(&c->open_buckets_wait);
 147                 closure_wake_up(&c->freelist_wait);
 148         } else {
 149                 bch2_open_bucket_put(c, ob);
 150         }
 151 }
 152
 153 static void verify_not_stale(struct bch_fs *c, const struct open_buckets *obs)
 154 {
 155 #ifdef CONFIG_BCACHEFS_DEBUG
 156         struct open_bucket *ob;
 157         unsigned i;
 158
 159         open_bucket_for_each(c, obs, ob, i) {
 160                 struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev);
 161
 162                 BUG_ON(ptr_stale(ca, &ob->ptr));
 163         }
 164 #endif
 165 }
 166
 167 /* _only_ for allocating the journal on a new device: */
 168 long bch2_bucket_alloc_new_fs(struct bch_dev *ca)
 169 {
 170         struct bucket_array *buckets;
 171         ssize_t b;
 172
 173         rcu_read_lock();
 174         buckets = bucket_array(ca);
 175
 176         for (b = ca->mi.first_bucket; b < ca->mi.nbuckets; b++)
 177                 if (is_available_bucket(buckets->b[b].mark))
 178                         goto success;
 179         b = -1;
 180 success:
 181         rcu_read_unlock();
 182         return b;
 183 }
 184
 185 static inline unsigned open_buckets_reserved(enum alloc_reserve reserve)
 186 {
 187         switch (reserve) {
 188         case RESERVE_ALLOC:
 189                 return 0;
 190         case RESERVE_BTREE:
 191                 return BTREE_NODE_RESERVE / 2;
 192         default:
 193                 return BTREE_NODE_RESERVE;
 194         }
 195 }
 196
 197 /**
 198  * bch_bucket_alloc - allocate a single bucket from a specific device
 199  *
 200  * Returns index of bucket on success, 0 on failure
 201  * */
 202 struct open_bucket *bch2_bucket_alloc(struct bch_fs *c, struct bch_dev *ca,
 203                                       enum alloc_reserve reserve,
 204                                       bool may_alloc_partial,
 205                                       struct closure *cl)
 206 {
 207         struct bucket_array *buckets;
 208         struct open_bucket *ob;
 209         long bucket = 0;
 210
 211         spin_lock(&c->freelist_lock);
 212
 213         if (may_alloc_partial &&
 214             ca->open_buckets_partial_nr) {
 215                 ob = c->open_buckets +
 216                         ca->open_buckets_partial[--ca->open_buckets_partial_nr];
 217                 ob->on_partial_list = false;
 218                 spin_unlock(&c->freelist_lock);
 219                 return ob;
 220         }
 221
 222         if (unlikely(c->open_buckets_nr_free <= open_buckets_reserved(reserve))) {
 223                 if (cl)
 224                         closure_wait(&c->open_buckets_wait, cl);
 225                 spin_unlock(&c->freelist_lock);
 226                 trace_open_bucket_alloc_fail(ca, reserve);
 227                 return ERR_PTR(-OPEN_BUCKETS_EMPTY);
 228         }
 229
 230         if (likely(fifo_pop(&ca->free[RESERVE_NONE], bucket)))
 231                 goto out;
 232
 233         switch (reserve) {
 234         case RESERVE_ALLOC:
 235                 if (fifo_pop(&ca->free[RESERVE_BTREE], bucket))
 236                         goto out;
 237                 break;
 238         case RESERVE_BTREE:
 239                 if (fifo_used(&ca->free[RESERVE_BTREE]) * 2 >=
 240                     ca->free[RESERVE_BTREE].size &&
 241                     fifo_pop(&ca->free[RESERVE_BTREE], bucket))
 242                         goto out;
 243                 break;
 244         case RESERVE_MOVINGGC:
 245                 if (fifo_pop(&ca->free[RESERVE_MOVINGGC], bucket))
 246                         goto out;
 247                 break;
 248         default:
 249                 break;
 250         }
 251
 252         if (cl)
 253                 closure_wait(&c->freelist_wait, cl);
 254
 255         spin_unlock(&c->freelist_lock);
 256
 257         trace_bucket_alloc_fail(ca, reserve);
 258         return ERR_PTR(-FREELIST_EMPTY);
 259 out:
 260         verify_not_on_freelist(c, ca, bucket);
 261
 262         ob = bch2_open_bucket_alloc(c);
 263
 264         spin_lock(&ob->lock);
 265         buckets = bucket_array(ca);
 266
 267         ob->valid       = true;
 268         ob->sectors_free = ca->mi.bucket_size;
 269         ob->ptr         = (struct bch_extent_ptr) {
 270                 .gen    = buckets->b[bucket].mark.gen,
 271                 .offset = bucket_to_sector(ca, bucket),
 272                 .dev    = ca->dev_idx,
 273         };
 274
 275         bucket_io_clock_reset(c, ca, bucket, READ);
 276         bucket_io_clock_reset(c, ca, bucket, WRITE);
 277         spin_unlock(&ob->lock);
 278
 279         spin_unlock(&c->freelist_lock);
 280
 281         bch2_wake_allocator(ca);
 282
 283         trace_bucket_alloc(ca, reserve);
 284         return ob;
 285 }
 286
 287 static int __dev_alloc_cmp(struct write_point *wp,
 288                            unsigned l, unsigned r)
 289 {
 290         return ((wp->next_alloc[l] > wp->next_alloc[r]) -
 291                 (wp->next_alloc[l] < wp->next_alloc[r]));
 292 }
 293
 294 #define dev_alloc_cmp(l, r) __dev_alloc_cmp(wp, l, r)
 295
 296 struct dev_alloc_list bch2_wp_alloc_list(struct bch_fs *c,
 297                                          struct write_point *wp,
 298                                          struct bch_devs_mask *devs)
 299 {
 300         struct dev_alloc_list ret = { .nr = 0 };
 301         struct bch_dev *ca;
 302         unsigned i;
 303
 304         for_each_member_device_rcu(ca, c, i, devs)
 305                 ret.devs[ret.nr++] = i;
 306
 307         bubble_sort(ret.devs, ret.nr, dev_alloc_cmp);
 308         return ret;
 309 }
 310
 311 void bch2_wp_rescale(struct bch_fs *c, struct bch_dev *ca,
 312                      struct write_point *wp)
 313 {
 314         u64 *v = wp->next_alloc + ca->dev_idx;
 315         u64 free_space = dev_buckets_free(c, ca);
 316         u64 free_space_inv = free_space
 317                 ? div64_u64(1ULL << 48, free_space)
 318                 : 1ULL << 48;
 319         u64 scale = *v / 4;
 320
 321         if (*v + free_space_inv >= *v)
 322                 *v += free_space_inv;
 323         else
 324                 *v = U64_MAX;
 325
 326         for (v = wp->next_alloc;
 327              v < wp->next_alloc + ARRAY_SIZE(wp->next_alloc); v++)
 328                 *v = *v < scale ? 0 : *v - scale;
 329 }
 330
 331 static int bch2_bucket_alloc_set(struct bch_fs *c,
 332                                  struct open_buckets *ptrs,
 333                                  struct write_point *wp,
 334                                  struct bch_devs_mask *devs_may_alloc,
 335                                  unsigned nr_replicas,
 336                                  unsigned *nr_effective,
 337                                  bool *have_cache,
 338                                  enum alloc_reserve reserve,
 339                                  struct closure *cl)
 340 {
 341         struct dev_alloc_list devs_sorted =
 342                 bch2_wp_alloc_list(c, wp, devs_may_alloc);
 343         struct bch_dev *ca;
 344         bool alloc_failure = false;
 345         unsigned i;
 346
 347         BUG_ON(*nr_effective >= nr_replicas);
 348
 349         for (i = 0; i < devs_sorted.nr; i++) {
 350                 struct open_bucket *ob;
 351
 352                 ca = rcu_dereference(c->devs[devs_sorted.devs[i]]);
 353                 if (!ca)
 354                         continue;
 355
 356                 if (!ca->mi.durability &&
 357                     (*have_cache ||
 358                      wp->type != BCH_DATA_USER))
 359                         continue;
 360
 361                 ob = bch2_bucket_alloc(c, ca, reserve,
 362                                        wp->type == BCH_DATA_USER, cl);
 363                 if (IS_ERR(ob)) {
 364                         enum bucket_alloc_ret ret = -PTR_ERR(ob);
 365
 366                         WARN_ON(reserve == RESERVE_MOVINGGC &&
 367                                 ret != OPEN_BUCKETS_EMPTY);
 368
 369                         if (cl)
 370                                 return -EAGAIN;
 371                         if (ret == OPEN_BUCKETS_EMPTY)
 372                                 return -ENOSPC;
 373                         alloc_failure = true;
 374                         continue;
 375                 }
 376
 377                 __clear_bit(ca->dev_idx, devs_may_alloc->d);
 378                 *nr_effective   += ca->mi.durability;
 379                 *have_cache     |= !ca->mi.durability;
 380
 381                 ob_push(c, ptrs, ob);
 382
 383                 bch2_wp_rescale(c, ca, wp);
 384
 385                 if (*nr_effective >= nr_replicas)
 386                         return 0;
 387         }
 388
 389         return alloc_failure ? -ENOSPC : -EROFS;
 390 }
 391
 392 /* Sector allocator */
 393
 394 static int get_buckets_from_writepoint(struct bch_fs *c,
 395                                        struct open_buckets *ptrs,
 396                                        struct write_point *wp,
 397                                        struct bch_devs_mask *devs_may_alloc,
 398                                        unsigned nr_replicas,
 399                                        unsigned *nr_effective,
 400                                        bool *have_cache)
 401 {
 402         struct open_buckets ptrs_skip = { .nr = 0 };
 403         struct open_bucket *ob;
 404         unsigned i;
 405
 406         open_bucket_for_each(c, &wp->ptrs, ob, i) {
 407                 struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev);
 408
 409                 if (*nr_effective < nr_replicas &&
 410                     test_bit(ob->ptr.dev, devs_may_alloc->d) &&
 411                     (ca->mi.durability ||
 412                      (wp->type == BCH_DATA_USER && !*have_cache))) {
 413                         __clear_bit(ob->ptr.dev, devs_may_alloc->d);
 414                         *nr_effective   += ca->mi.durability;
 415                         *have_cache     |= !ca->mi.durability;
 416
 417                         ob_push(c, ptrs, ob);
 418                 } else {
 419                         ob_push(c, &ptrs_skip, ob);
 420                 }
 421         }
 422         wp->ptrs = ptrs_skip;
 423
 424         return *nr_effective < nr_replicas ? -ENOSPC : 0;
 425 }
 426
 427 static int open_bucket_add_buckets(struct bch_fs *c,
 428                                    struct open_buckets *ptrs,
 429                                    struct write_point *wp,
 430                                    struct bch_devs_list *devs_have,
 431                                    u16 target,
 432                                    unsigned nr_replicas,
 433                                    unsigned *nr_effective,
 434                                    bool *have_cache,
 435                                    enum alloc_reserve reserve,
 436                                    struct closure *cl)
 437 {
 438         struct bch_devs_mask devs;
 439         const struct bch_devs_mask *t;
 440         struct open_bucket *ob;
 441         unsigned i;
 442         int ret;
 443
 444         percpu_down_read_preempt_disable(&c->usage_lock);
 445         rcu_read_lock();
 446
 447         devs = c->rw_devs[wp->type];
 448
 449         /* Don't allocate from devices we already have pointers to: */
 450         for (i = 0; i < devs_have->nr; i++)
 451                 __clear_bit(devs_have->devs[i], devs.d);
 452
 453         open_bucket_for_each(c, ptrs, ob, i)
 454                 __clear_bit(ob->ptr.dev, devs.d);
 455
 456         t = bch2_target_to_mask(c, target);
 457         if (t)
 458                 bitmap_and(devs.d, devs.d, t->d, BCH_SB_MEMBERS_MAX);
 459
 460         ret = get_buckets_from_writepoint(c, ptrs, wp, &devs,
 461                                 nr_replicas, nr_effective, have_cache);
 462         if (!ret)
 463                 goto out;
 464
 465         /*
 466          * Try nonblocking first, so that if one device is full we'll try from
 467          * other devices:
 468          */
 469         ret = bch2_bucket_alloc_set(c, ptrs, wp, &devs,
 470                                 nr_replicas, nr_effective, have_cache,
 471                                 reserve, NULL);
 472         if (!ret || ret == -EROFS || !cl)
 473                 goto out;
 474
 475         ret = bch2_bucket_alloc_set(c, ptrs, wp, &devs,
 476                                 nr_replicas, nr_effective, have_cache,
 477                                 reserve, cl);
 478 out:
 479         rcu_read_unlock();
 480         percpu_up_read_preempt_enable(&c->usage_lock);
 481
 482         return ret;
 483 }
 484
 485 void bch2_writepoint_stop(struct bch_fs *c, struct bch_dev *ca,
 486                           struct write_point *wp)
 487 {
 488         struct open_buckets ptrs = { .nr = 0 };
 489         struct open_bucket *ob;
 490         unsigned i;
 491
 492         mutex_lock(&wp->lock);
 493         open_bucket_for_each(c, &wp->ptrs, ob, i)
 494                 if (ob->ptr.dev == ca->dev_idx)
 495                         open_bucket_free_unused(c, wp, ob);
 496                 else
 497                         ob_push(c, &ptrs, ob);
 498
 499         wp->ptrs = ptrs;
 500         mutex_unlock(&wp->lock);
 501 }
 502
 503 static struct write_point *__writepoint_find(struct hlist_head *head,
 504                                              unsigned long write_point)
 505 {
 506         struct write_point *wp;
 507
 508         hlist_for_each_entry_rcu(wp, head, node)
 509                 if (wp->write_point == write_point)
 510                         return wp;
 511
 512         return NULL;
 513 }
 514
 515 static struct write_point *writepoint_find(struct bch_fs *c,
 516                                            unsigned long write_point)
 517 {
 518         struct write_point *wp, *oldest;
 519         struct hlist_head *head;
 520
 521         if (!(write_point & 1UL)) {
 522                 wp = (struct write_point *) write_point;
 523                 mutex_lock(&wp->lock);
 524                 return wp;
 525         }
 526
 527         head = writepoint_hash(c, write_point);
 528 restart_find:
 529         wp = __writepoint_find(head, write_point);
 530         if (wp) {
 531 lock_wp:
 532                 mutex_lock(&wp->lock);
 533                 if (wp->write_point == write_point)
 534                         goto out;
 535                 mutex_unlock(&wp->lock);
 536                 goto restart_find;
 537         }
 538
 539         oldest = NULL;
 540         for (wp = c->write_points;
 541              wp < c->write_points + ARRAY_SIZE(c->write_points);
 542              wp++)
 543                 if (!oldest || time_before64(wp->last_used, oldest->last_used))
 544                         oldest = wp;
 545
 546         mutex_lock(&oldest->lock);
 547         mutex_lock(&c->write_points_hash_lock);
 548         wp = __writepoint_find(head, write_point);
 549         if (wp && wp != oldest) {
 550                 mutex_unlock(&c->write_points_hash_lock);
 551                 mutex_unlock(&oldest->lock);
 552                 goto lock_wp;
 553         }
 554
 555         wp = oldest;
 556         hlist_del_rcu(&wp->node);
 557         wp->write_point = write_point;
 558         hlist_add_head_rcu(&wp->node, head);
 559         mutex_unlock(&c->write_points_hash_lock);
 560 out:
 561         wp->last_used = sched_clock();
 562         return wp;
 563 }
 564
 565 /*
 566  * Get us an open_bucket we can allocate from, return with it locked:
 567  */
 568 struct write_point *bch2_alloc_sectors_start(struct bch_fs *c,
 569                                 unsigned target,
 570                                 struct write_point_specifier write_point,
 571                                 struct bch_devs_list *devs_have,
 572                                 unsigned nr_replicas,
 573                                 unsigned nr_replicas_required,
 574                                 enum alloc_reserve reserve,
 575                                 unsigned flags,
 576                                 struct closure *cl)
 577 {
 578         struct write_point *wp;
 579         struct open_bucket *ob;
 580         unsigned nr_effective = 0;
 581         struct open_buckets ptrs = { .nr = 0 };
 582         bool have_cache = false;
 583         int ret = 0, i;
 584
 585         BUG_ON(!nr_replicas || !nr_replicas_required);
 586
 587         wp = writepoint_find(c, write_point.v);
 588
 589         if (!target || (flags & BCH_WRITE_ONLY_SPECIFIED_DEVS)) {
 590                 ret = open_bucket_add_buckets(c, &ptrs, wp, devs_have, target,
 591                                               nr_replicas, &nr_effective,
 592                                               &have_cache, reserve, cl);
 593         } else {
 594                 ret = open_bucket_add_buckets(c, &ptrs, wp, devs_have, target,
 595                                               nr_replicas, &nr_effective,
 596                                               &have_cache, reserve, NULL);
 597                 if (!ret)
 598                         goto alloc_done;
 599
 600                 ret = open_bucket_add_buckets(c, &ptrs, wp, devs_have, 0,
 601                                               nr_replicas, &nr_effective,
 602                                               &have_cache, reserve, cl);
 603         }
 604 alloc_done:
 605         BUG_ON(!ret && nr_effective < nr_replicas);
 606
 607         if (ret == -EROFS &&
 608             nr_effective >= nr_replicas_required)
 609                 ret = 0;
 610
 611         if (ret)
 612                 goto err;
 613
 614         /* Free buckets we didn't use: */
 615         open_bucket_for_each(c, &wp->ptrs, ob, i)
 616                 open_bucket_free_unused(c, wp, ob);
 617
 618         wp->ptrs = ptrs;
 619
 620         wp->sectors_free = UINT_MAX;
 621
 622         open_bucket_for_each(c, &wp->ptrs, ob, i)
 623                 wp->sectors_free = min(wp->sectors_free, ob->sectors_free);
 624
 625         BUG_ON(!wp->sectors_free || wp->sectors_free == UINT_MAX);
 626
 627         verify_not_stale(c, &wp->ptrs);
 628
 629         return wp;
 630 err:
 631         open_bucket_for_each(c, &wp->ptrs, ob, i)
 632                 if (ptrs.nr < ARRAY_SIZE(ptrs.v))
 633                         ob_push(c, &ptrs, ob);
 634                 else
 635                         open_bucket_free_unused(c, wp, ob);
 636         wp->ptrs = ptrs;
 637
 638         mutex_unlock(&wp->lock);
 639         return ERR_PTR(ret);
 640 }
 641
 642 /*
 643  * Append pointers to the space we just allocated to @k, and mark @sectors space
 644  * as allocated out of @ob
 645  */
 646 void bch2_alloc_sectors_append_ptrs(struct bch_fs *c, struct write_point *wp,
 647                                     struct bkey_i_extent *e, unsigned sectors)
 648 {
 649         struct open_bucket *ob;
 650         unsigned i;
 651
 652         BUG_ON(sectors > wp->sectors_free);
 653         wp->sectors_free -= sectors;
 654
 655         open_bucket_for_each(c, &wp->ptrs, ob, i) {
 656                 struct bch_dev *ca = bch_dev_bkey_exists(c, ob->ptr.dev);
 657                 struct bch_extent_ptr tmp = ob->ptr;
 658
 659                 EBUG_ON(bch2_extent_has_device(extent_i_to_s_c(e), ob->ptr.dev));
 660
 661                 tmp.cached = bkey_extent_is_cached(&e->k) ||
 662                         (!ca->mi.durability && wp->type == BCH_DATA_USER);
 663
 664                 tmp.offset += ca->mi.bucket_size - ob->sectors_free;
 665                 extent_ptr_append(e, tmp);
 666
 667                 BUG_ON(sectors > ob->sectors_free);
 668                 ob->sectors_free -= sectors;
 669         }
 670 }
 671
 672 /*
 673  * Append pointers to the space we just allocated to @k, and mark @sectors space
 674  * as allocated out of @ob
 675  */
 676 void bch2_alloc_sectors_done(struct bch_fs *c, struct write_point *wp)
 677 {
 678         struct open_buckets ptrs = { .nr = 0 }, keep = { .nr = 0 };
 679         struct open_bucket *ob;
 680         unsigned i;
 681
 682         open_bucket_for_each(c, &wp->ptrs, ob, i)
 683                 ob_push(c, !ob->sectors_free ? &ptrs : &keep, ob);
 684         wp->ptrs = keep;
 685
 686         mutex_unlock(&wp->lock);
 687
 688         bch2_open_buckets_put(c, &ptrs);
 689 }