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

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include "bcachefs.h"
   4 #include "alloc_foreground.h"
   5 #include "bkey_buf.h"
   6 #include "btree_update.h"
   7 #include "buckets.h"
   8 #include "data_update.h"
   9 #include "ec.h"
  10 #include "error.h"
  11 #include "extents.h"
  12 #include "io_write.h"
  13 #include "keylist.h"
  14 #include "move.h"
  15 #include "nocow_locking.h"
  16 #include "rebalance.h"
  17 #include "subvolume.h"
  18 #include "trace.h"
  19
  20 static void trace_move_extent_finish2(struct bch_fs *c, struct bkey_s_c k)
  21 {
  22         if (trace_move_extent_finish_enabled()) {
  23                 struct printbuf buf = PRINTBUF;
  24
  25                 bch2_bkey_val_to_text(&buf, c, k);
  26                 trace_move_extent_finish(c, buf.buf);
  27                 printbuf_exit(&buf);
  28         }
  29 }
  30
  31 static void trace_move_extent_fail2(struct data_update *m,
  32                          struct bkey_s_c new,
  33                          struct bkey_s_c wrote,
  34                          struct bkey_i *insert,
  35                          const char *msg)
  36 {
  37         struct bch_fs *c = m->op.c;
  38         struct bkey_s_c old = bkey_i_to_s_c(m->k.k);
  39         const union bch_extent_entry *entry;
  40         struct bch_extent_ptr *ptr;
  41         struct extent_ptr_decoded p;
  42         struct printbuf buf = PRINTBUF;
  43         unsigned i, rewrites_found = 0;
  44
  45         if (!trace_move_extent_fail_enabled())
  46                 return;
  47
  48         prt_str(&buf, msg);
  49
  50         if (insert) {
  51                 i = 0;
  52                 bkey_for_each_ptr_decode(old.k, bch2_bkey_ptrs_c(old), p, entry) {
  53                         if (((1U << i) & m->data_opts.rewrite_ptrs) &&
  54                             (ptr = bch2_extent_has_ptr(old, p, bkey_i_to_s(insert))) &&
  55                             !ptr->cached)
  56                                 rewrites_found |= 1U << i;
  57                         i++;
  58                 }
  59         }
  60
  61         prt_printf(&buf, "\nrewrite ptrs:   %u%u%u%u",
  62                    (m->data_opts.rewrite_ptrs & (1 << 0)) != 0,
  63                    (m->data_opts.rewrite_ptrs & (1 << 1)) != 0,
  64                    (m->data_opts.rewrite_ptrs & (1 << 2)) != 0,
  65                    (m->data_opts.rewrite_ptrs & (1 << 3)) != 0);
  66
  67         prt_printf(&buf, "\nrewrites found: %u%u%u%u",
  68                    (rewrites_found & (1 << 0)) != 0,
  69                    (rewrites_found & (1 << 1)) != 0,
  70                    (rewrites_found & (1 << 2)) != 0,
  71                    (rewrites_found & (1 << 3)) != 0);
  72
  73         prt_str(&buf, "\nold:    ");
  74         bch2_bkey_val_to_text(&buf, c, old);
  75
  76         prt_str(&buf, "\nnew:    ");
  77         bch2_bkey_val_to_text(&buf, c, new);
  78
  79         prt_str(&buf, "\nwrote:  ");
  80         bch2_bkey_val_to_text(&buf, c, wrote);
  81
  82         if (insert) {
  83                 prt_str(&buf, "\ninsert: ");
  84                 bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(insert));
  85         }
  86
  87         trace_move_extent_fail(c, buf.buf);
  88         printbuf_exit(&buf);
  89 }
  90
  91 static int __bch2_data_update_index_update(struct btree_trans *trans,
  92                                            struct bch_write_op *op)
  93 {
  94         struct bch_fs *c = op->c;
  95         struct btree_iter iter;
  96         struct data_update *m =
  97                 container_of(op, struct data_update, op);
  98         struct keylist *keys = &op->insert_keys;
  99         struct bkey_buf _new, _insert;
 100         int ret = 0;
 101
 102         bch2_bkey_buf_init(&_new);
 103         bch2_bkey_buf_init(&_insert);
 104         bch2_bkey_buf_realloc(&_insert, c, U8_MAX);
 105
 106         bch2_trans_iter_init(trans, &iter, m->btree_id,
 107                              bkey_start_pos(&bch2_keylist_front(keys)->k),
 108                              BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
 109
 110         while (1) {
 111                 struct bkey_s_c k;
 112                 struct bkey_s_c old = bkey_i_to_s_c(m->k.k);
 113                 struct bkey_i *insert = NULL;
 114                 struct bkey_i_extent *new;
 115                 const union bch_extent_entry *entry_c;
 116                 union bch_extent_entry *entry;
 117                 struct extent_ptr_decoded p;
 118                 struct bch_extent_ptr *ptr;
 119                 const struct bch_extent_ptr *ptr_c;
 120                 struct bpos next_pos;
 121                 bool should_check_enospc;
 122                 s64 i_sectors_delta = 0, disk_sectors_delta = 0;
 123                 unsigned rewrites_found = 0, durability, i;
 124
 125                 bch2_trans_begin(trans);
 126
 127                 k = bch2_btree_iter_peek_slot(&iter);
 128                 ret = bkey_err(k);
 129                 if (ret)
 130                         goto err;
 131
 132                 new = bkey_i_to_extent(bch2_keylist_front(keys));
 133
 134                 if (!bch2_extents_match(k, old)) {
 135                         trace_move_extent_fail2(m, k, bkey_i_to_s_c(&new->k_i),
 136                                                 NULL, "no match:");
 137                         goto nowork;
 138                 }
 139
 140                 bkey_reassemble(_insert.k, k);
 141                 insert = _insert.k;
 142
 143                 bch2_bkey_buf_copy(&_new, c, bch2_keylist_front(keys));
 144                 new = bkey_i_to_extent(_new.k);
 145                 bch2_cut_front(iter.pos, &new->k_i);
 146
 147                 bch2_cut_front(iter.pos,        insert);
 148                 bch2_cut_back(new->k.p,         insert);
 149                 bch2_cut_back(insert->k.p,      &new->k_i);
 150
 151                 /*
 152                  * @old: extent that we read from
 153                  * @insert: key that we're going to update, initialized from
 154                  * extent currently in btree - same as @old unless we raced with
 155                  * other updates
 156                  * @new: extent with new pointers that we'll be adding to @insert
 157                  *
 158                  * Fist, drop rewrite_ptrs from @new:
 159                  */
 160                 i = 0;
 161                 bkey_for_each_ptr_decode(old.k, bch2_bkey_ptrs_c(old), p, entry_c) {
 162                         if (((1U << i) & m->data_opts.rewrite_ptrs) &&
 163                             (ptr = bch2_extent_has_ptr(old, p, bkey_i_to_s(insert))) &&
 164                             !ptr->cached) {
 165                                 bch2_extent_ptr_set_cached(bkey_i_to_s(insert), ptr);
 166                                 rewrites_found |= 1U << i;
 167                         }
 168                         i++;
 169                 }
 170
 171                 if (m->data_opts.rewrite_ptrs &&
 172                     !rewrites_found &&
 173                     bch2_bkey_durability(c, k) >= m->op.opts.data_replicas) {
 174                         trace_move_extent_fail2(m, k, bkey_i_to_s_c(&new->k_i), insert, "no rewrites found:");
 175                         goto nowork;
 176                 }
 177
 178                 /*
 179                  * A replica that we just wrote might conflict with a replica
 180                  * that we want to keep, due to racing with another move:
 181                  */
 182 restart_drop_conflicting_replicas:
 183                 extent_for_each_ptr(extent_i_to_s(new), ptr)
 184                         if ((ptr_c = bch2_bkey_has_device_c(bkey_i_to_s_c(insert), ptr->dev)) &&
 185                             !ptr_c->cached) {
 186                                 bch2_bkey_drop_ptr_noerror(bkey_i_to_s(&new->k_i), ptr);
 187                                 goto restart_drop_conflicting_replicas;
 188                         }
 189
 190                 if (!bkey_val_u64s(&new->k)) {
 191                         trace_move_extent_fail2(m, k, bkey_i_to_s_c(&new->k_i), insert, "new replicas conflicted:");
 192                         goto nowork;
 193                 }
 194
 195                 /* Now, drop pointers that conflict with what we just wrote: */
 196                 extent_for_each_ptr_decode(extent_i_to_s(new), p, entry)
 197                         if ((ptr = bch2_bkey_has_device(bkey_i_to_s(insert), p.ptr.dev)))
 198                                 bch2_bkey_drop_ptr_noerror(bkey_i_to_s(insert), ptr);
 199
 200                 durability = bch2_bkey_durability(c, bkey_i_to_s_c(insert)) +
 201                         bch2_bkey_durability(c, bkey_i_to_s_c(&new->k_i));
 202
 203                 /* Now, drop excess replicas: */
 204 restart_drop_extra_replicas:
 205                 bkey_for_each_ptr_decode(old.k, bch2_bkey_ptrs(bkey_i_to_s(insert)), p, entry) {
 206                         unsigned ptr_durability = bch2_extent_ptr_durability(c, &p);
 207
 208                         if (!p.ptr.cached &&
 209                             durability - ptr_durability >= m->op.opts.data_replicas) {
 210                                 durability -= ptr_durability;
 211
 212                                 bch2_extent_ptr_set_cached(bkey_i_to_s(insert), &entry->ptr);
 213                                 goto restart_drop_extra_replicas;
 214                         }
 215                 }
 216
 217                 /* Finally, add the pointers we just wrote: */
 218                 extent_for_each_ptr_decode(extent_i_to_s(new), p, entry)
 219                         bch2_extent_ptr_decoded_append(insert, &p);
 220
 221                 bch2_bkey_narrow_crcs(insert, (struct bch_extent_crc_unpacked) { 0 });
 222                 bch2_extent_normalize(c, bkey_i_to_s(insert));
 223
 224                 ret = bch2_sum_sector_overwrites(trans, &iter, insert,
 225                                                  &should_check_enospc,
 226                                                  &i_sectors_delta,
 227                                                  &disk_sectors_delta);
 228                 if (ret)
 229                         goto err;
 230
 231                 if (disk_sectors_delta > (s64) op->res.sectors) {
 232                         ret = bch2_disk_reservation_add(c, &op->res,
 233                                                 disk_sectors_delta - op->res.sectors,
 234                                                 !should_check_enospc
 235                                                 ? BCH_DISK_RESERVATION_NOFAIL : 0);
 236                         if (ret)
 237                                 goto out;
 238                 }
 239
 240                 next_pos = insert->k.p;
 241
 242                 /*
 243                  * Check for nonce offset inconsistency:
 244                  * This is debug code - we've been seeing this bug rarely, and
 245                  * it's been hard to reproduce, so this should give us some more
 246                  * information when it does occur:
 247                  */
 248                 struct printbuf err = PRINTBUF;
 249                 int invalid = bch2_bkey_invalid(c, bkey_i_to_s_c(insert), __btree_node_type(0, m->btree_id), 0, &err);
 250                 printbuf_exit(&err);
 251
 252                 if (invalid) {
 253                         struct printbuf buf = PRINTBUF;
 254
 255                         prt_str(&buf, "about to insert invalid key in data update path");
 256                         prt_str(&buf, "\nold: ");
 257                         bch2_bkey_val_to_text(&buf, c, old);
 258                         prt_str(&buf, "\nk:   ");
 259                         bch2_bkey_val_to_text(&buf, c, k);
 260                         prt_str(&buf, "\nnew: ");
 261                         bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(insert));
 262
 263                         bch2_print_string_as_lines(KERN_ERR, buf.buf);
 264                         printbuf_exit(&buf);
 265
 266                         bch2_fatal_error(c);
 267                         goto out;
 268                 }
 269
 270                 ret =   bch2_insert_snapshot_whiteouts(trans, m->btree_id,
 271                                                 k.k->p, bkey_start_pos(&insert->k)) ?:
 272                         bch2_insert_snapshot_whiteouts(trans, m->btree_id,
 273                                                 k.k->p, insert->k.p) ?:
 274                         bch2_bkey_set_needs_rebalance(c, insert,
 275                                                       op->opts.background_target,
 276                                                       op->opts.background_compression) ?:
 277                         bch2_trans_update(trans, &iter, insert,
 278                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?:
 279                         bch2_trans_commit(trans, &op->res,
 280                                 NULL,
 281                                 BCH_TRANS_COMMIT_no_check_rw|
 282                                 BCH_TRANS_COMMIT_no_enospc|
 283                                 m->data_opts.btree_insert_flags);
 284                 if (!ret) {
 285                         bch2_btree_iter_set_pos(&iter, next_pos);
 286
 287                         this_cpu_add(c->counters[BCH_COUNTER_move_extent_finish], new->k.size);
 288                         trace_move_extent_finish2(c, bkey_i_to_s_c(&new->k_i));
 289                 }
 290 err:
 291                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 292                         ret = 0;
 293                 if (ret)
 294                         break;
 295 next:
 296                 while (bkey_ge(iter.pos, bch2_keylist_front(keys)->k.p)) {
 297                         bch2_keylist_pop_front(keys);
 298                         if (bch2_keylist_empty(keys))
 299                                 goto out;
 300                 }
 301                 continue;
 302 nowork:
 303                 if (m->stats && m->stats) {
 304                         BUG_ON(k.k->p.offset <= iter.pos.offset);
 305                         atomic64_inc(&m->stats->keys_raced);
 306                         atomic64_add(k.k->p.offset - iter.pos.offset,
 307                                      &m->stats->sectors_raced);
 308                 }
 309
 310                 this_cpu_inc(c->counters[BCH_COUNTER_move_extent_fail]);
 311
 312                 bch2_btree_iter_advance(&iter);
 313                 goto next;
 314         }
 315 out:
 316         bch2_trans_iter_exit(trans, &iter);
 317         bch2_bkey_buf_exit(&_insert, c);
 318         bch2_bkey_buf_exit(&_new, c);
 319         BUG_ON(bch2_err_matches(ret, BCH_ERR_transaction_restart));
 320         return ret;
 321 }
 322
 323 int bch2_data_update_index_update(struct bch_write_op *op)
 324 {
 325         return bch2_trans_run(op->c, __bch2_data_update_index_update(trans, op));
 326 }
 327
 328 void bch2_data_update_read_done(struct data_update *m,
 329                                 struct bch_extent_crc_unpacked crc)
 330 {
 331         /* write bio must own pages: */
 332         BUG_ON(!m->op.wbio.bio.bi_vcnt);
 333
 334         m->op.crc = crc;
 335         m->op.wbio.bio.bi_iter.bi_size = crc.compressed_size << 9;
 336
 337         closure_call(&m->op.cl, bch2_write, NULL, NULL);
 338 }
 339
 340 void bch2_data_update_exit(struct data_update *update)
 341 {
 342         struct bch_fs *c = update->op.c;
 343         struct bkey_ptrs_c ptrs =
 344                 bch2_bkey_ptrs_c(bkey_i_to_s_c(update->k.k));
 345         const struct bch_extent_ptr *ptr;
 346
 347         bkey_for_each_ptr(ptrs, ptr) {
 348                 if (c->opts.nocow_enabled)
 349                         bch2_bucket_nocow_unlock(&c->nocow_locks,
 350                                                  PTR_BUCKET_POS(c, ptr), 0);
 351                 percpu_ref_put(&bch_dev_bkey_exists(c, ptr->dev)->ref);
 352         }
 353
 354         bch2_bkey_buf_exit(&update->k, c);
 355         bch2_disk_reservation_put(c, &update->op.res);
 356         bch2_bio_free_pages_pool(c, &update->op.wbio.bio);
 357 }
 358
 359 void bch2_update_unwritten_extent(struct btree_trans *trans,
 360                                   struct data_update *update)
 361 {
 362         struct bch_fs *c = update->op.c;
 363         struct bio *bio = &update->op.wbio.bio;
 364         struct bkey_i_extent *e;
 365         struct write_point *wp;
 366         struct bch_extent_ptr *ptr;
 367         struct closure cl;
 368         struct btree_iter iter;
 369         struct bkey_s_c k;
 370         int ret;
 371
 372         closure_init_stack(&cl);
 373         bch2_keylist_init(&update->op.insert_keys, update->op.inline_keys);
 374
 375         while (bio_sectors(bio)) {
 376                 unsigned sectors = bio_sectors(bio);
 377
 378                 bch2_trans_iter_init(trans, &iter, update->btree_id, update->op.pos,
 379                                      BTREE_ITER_SLOTS);
 380                 ret = lockrestart_do(trans, ({
 381                         k = bch2_btree_iter_peek_slot(&iter);
 382                         bkey_err(k);
 383                 }));
 384                 bch2_trans_iter_exit(trans, &iter);
 385
 386                 if (ret || !bch2_extents_match(k, bkey_i_to_s_c(update->k.k)))
 387                         break;
 388
 389                 e = bkey_extent_init(update->op.insert_keys.top);
 390                 e->k.p = update->op.pos;
 391
 392                 ret = bch2_alloc_sectors_start_trans(trans,
 393                                 update->op.target,
 394                                 false,
 395                                 update->op.write_point,
 396                                 &update->op.devs_have,
 397                                 update->op.nr_replicas,
 398                                 update->op.nr_replicas,
 399                                 update->op.watermark,
 400                                 0, &cl, &wp);
 401                 if (bch2_err_matches(ret, BCH_ERR_operation_blocked)) {
 402                         bch2_trans_unlock(trans);
 403                         closure_sync(&cl);
 404                         continue;
 405                 }
 406
 407                 if (ret)
 408                         return;
 409
 410                 sectors = min(sectors, wp->sectors_free);
 411
 412                 bch2_key_resize(&e->k, sectors);
 413
 414                 bch2_open_bucket_get(c, wp, &update->op.open_buckets);
 415                 bch2_alloc_sectors_append_ptrs(c, wp, &e->k_i, sectors, false);
 416                 bch2_alloc_sectors_done(c, wp);
 417
 418                 bio_advance(bio, sectors << 9);
 419                 update->op.pos.offset += sectors;
 420
 421                 extent_for_each_ptr(extent_i_to_s(e), ptr)
 422                         ptr->unwritten = true;
 423                 bch2_keylist_push(&update->op.insert_keys);
 424
 425                 ret = __bch2_data_update_index_update(trans, &update->op);
 426
 427                 bch2_open_buckets_put(c, &update->op.open_buckets);
 428
 429                 if (ret)
 430                         break;
 431         }
 432
 433         if (closure_nr_remaining(&cl) != 1) {
 434                 bch2_trans_unlock(trans);
 435                 closure_sync(&cl);
 436         }
 437 }
 438
 439 int bch2_data_update_init(struct btree_trans *trans,
 440                           struct moving_context *ctxt,
 441                           struct data_update *m,
 442                           struct write_point_specifier wp,
 443                           struct bch_io_opts io_opts,
 444                           struct data_update_opts data_opts,
 445                           enum btree_id btree_id,
 446                           struct bkey_s_c k)
 447 {
 448         struct bch_fs *c = trans->c;
 449         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
 450         const union bch_extent_entry *entry;
 451         struct extent_ptr_decoded p;
 452         const struct bch_extent_ptr *ptr;
 453         unsigned i, reserve_sectors = k.k->size * data_opts.extra_replicas;
 454         unsigned ptrs_locked = 0;
 455         int ret;
 456
 457         bch2_bkey_buf_init(&m->k);
 458         bch2_bkey_buf_reassemble(&m->k, c, k);
 459         m->btree_id     = btree_id;
 460         m->data_opts    = data_opts;
 461         m->ctxt         = ctxt;
 462         m->stats        = ctxt ? ctxt->stats : NULL;
 463
 464         bch2_write_op_init(&m->op, c, io_opts);
 465         m->op.pos       = bkey_start_pos(k.k);
 466         m->op.version   = k.k->version;
 467         m->op.target    = data_opts.target;
 468         m->op.write_point = wp;
 469         m->op.nr_replicas = 0;
 470         m->op.flags     |= BCH_WRITE_PAGES_STABLE|
 471                 BCH_WRITE_PAGES_OWNED|
 472                 BCH_WRITE_DATA_ENCODED|
 473                 BCH_WRITE_MOVE|
 474                 m->data_opts.write_flags;
 475         m->op.compression_opt   = io_opts.background_compression ?: io_opts.compression;
 476         m->op.watermark         = m->data_opts.btree_insert_flags & BCH_WATERMARK_MASK;
 477
 478         bkey_for_each_ptr(ptrs, ptr)
 479                 percpu_ref_get(&bch_dev_bkey_exists(c, ptr->dev)->ref);
 480
 481         i = 0;
 482         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 483                 bool locked;
 484
 485                 if (((1U << i) & m->data_opts.rewrite_ptrs)) {
 486                         BUG_ON(p.ptr.cached);
 487
 488                         if (crc_is_compressed(p.crc))
 489                                 reserve_sectors += k.k->size;
 490
 491                         m->op.nr_replicas += bch2_extent_ptr_desired_durability(c, &p);
 492                 } else if (!p.ptr.cached) {
 493                         bch2_dev_list_add_dev(&m->op.devs_have, p.ptr.dev);
 494                 }
 495
 496                 /*
 497                  * op->csum_type is normally initialized from the fs/file's
 498                  * current options - but if an extent is encrypted, we require
 499                  * that it stays encrypted:
 500                  */
 501                 if (bch2_csum_type_is_encryption(p.crc.csum_type)) {
 502                         m->op.nonce     = p.crc.nonce + p.crc.offset;
 503                         m->op.csum_type = p.crc.csum_type;
 504                 }
 505
 506                 if (p.crc.compression_type == BCH_COMPRESSION_TYPE_incompressible)
 507                         m->op.incompressible = true;
 508
 509                 if (c->opts.nocow_enabled) {
 510                         if (ctxt) {
 511                                 move_ctxt_wait_event(ctxt,
 512                                                 (locked = bch2_bucket_nocow_trylock(&c->nocow_locks,
 513                                                                           PTR_BUCKET_POS(c, &p.ptr), 0)) ||
 514                                                 !atomic_read(&ctxt->read_sectors));
 515
 516                                 if (!locked)
 517                                         bch2_bucket_nocow_lock(&c->nocow_locks,
 518                                                                PTR_BUCKET_POS(c, &p.ptr), 0);
 519                         } else {
 520                                 if (!bch2_bucket_nocow_trylock(&c->nocow_locks,
 521                                                                PTR_BUCKET_POS(c, &p.ptr), 0)) {
 522                                         ret = -BCH_ERR_nocow_lock_blocked;
 523                                         goto err;
 524                                 }
 525                         }
 526                         ptrs_locked |= (1U << i);
 527                 }
 528
 529                 i++;
 530         }
 531
 532         if (reserve_sectors) {
 533                 ret = bch2_disk_reservation_add(c, &m->op.res, reserve_sectors,
 534                                 m->data_opts.extra_replicas
 535                                 ? 0
 536                                 : BCH_DISK_RESERVATION_NOFAIL);
 537                 if (ret)
 538                         goto err;
 539         }
 540
 541         m->op.nr_replicas += m->data_opts.extra_replicas;
 542         m->op.nr_replicas_required = m->op.nr_replicas;
 543
 544         BUG_ON(!m->op.nr_replicas);
 545
 546         /* Special handling required: */
 547         if (bkey_extent_is_unwritten(k))
 548                 return -BCH_ERR_unwritten_extent_update;
 549         return 0;
 550 err:
 551         i = 0;
 552         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 553                 if ((1U << i) & ptrs_locked)
 554                         bch2_bucket_nocow_unlock(&c->nocow_locks,
 555                                                  PTR_BUCKET_POS(c, &p.ptr), 0);
 556                 percpu_ref_put(&bch_dev_bkey_exists(c, p.ptr.dev)->ref);
 557                 i++;
 558         }
 559
 560         bch2_bkey_buf_exit(&m->k, c);
 561         bch2_bio_free_pages_pool(c, &m->op.wbio.bio);
 562         return ret;
 563 }
 564
 565 void bch2_data_update_opts_normalize(struct bkey_s_c k, struct data_update_opts *opts)
 566 {
 567         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
 568         const struct bch_extent_ptr *ptr;
 569         unsigned i = 0;
 570
 571         bkey_for_each_ptr(ptrs, ptr) {
 572                 if ((opts->rewrite_ptrs & (1U << i)) && ptr->cached) {
 573                         opts->kill_ptrs |= 1U << i;
 574                         opts->rewrite_ptrs ^= 1U << i;
 575                 }
 576
 577                 i++;
 578         }
 579 }