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.h"
  13 #include "keylist.h"
  14 #include "move.h"
  15 #include "nocow_locking.h"
  16 #include "subvolume.h"
  17
  18 #include <trace/events/bcachefs.h>
  19
  20 static int insert_snapshot_whiteouts(struct btree_trans *trans,
  21                                      enum btree_id id,
  22                                      struct bpos old_pos,
  23                                      struct bpos new_pos)
  24 {
  25         struct bch_fs *c = trans->c;
  26         struct btree_iter iter, iter2;
  27         struct bkey_s_c k, k2;
  28         snapshot_id_list s;
  29         struct bkey_i *update;
  30         int ret;
  31
  32         if (!btree_type_has_snapshots(id))
  33                 return 0;
  34
  35         darray_init(&s);
  36
  37         if (!bch2_snapshot_has_children(c, old_pos.snapshot))
  38                 return 0;
  39
  40         bch2_trans_iter_init(trans, &iter, id, old_pos,
  41                              BTREE_ITER_NOT_EXTENTS|
  42                              BTREE_ITER_ALL_SNAPSHOTS);
  43         while (1) {
  44                 k = bch2_btree_iter_prev(&iter);
  45                 ret = bkey_err(k);
  46                 if (ret)
  47                         break;
  48
  49                 if (!k.k)
  50                         break;
  51
  52                 if (!bkey_eq(old_pos, k.k->p))
  53                         break;
  54
  55                 if (bch2_snapshot_is_ancestor(c, k.k->p.snapshot, old_pos.snapshot) &&
  56                     !snapshot_list_has_ancestor(c, &s, k.k->p.snapshot)) {
  57                         struct bpos whiteout_pos = new_pos;
  58
  59                         whiteout_pos.snapshot = k.k->p.snapshot;
  60
  61                         bch2_trans_iter_init(trans, &iter2, id, whiteout_pos,
  62                                              BTREE_ITER_NOT_EXTENTS|
  63                                              BTREE_ITER_INTENT);
  64                         k2 = bch2_btree_iter_peek_slot(&iter2);
  65                         ret = bkey_err(k2);
  66
  67                         if (!ret && k2.k->type == KEY_TYPE_deleted) {
  68                                 update = bch2_trans_kmalloc(trans, sizeof(struct bkey_i));
  69                                 ret = PTR_ERR_OR_ZERO(update);
  70                                 if (ret)
  71                                         break;
  72
  73                                 bkey_init(&update->k);
  74                                 update->k.p             = whiteout_pos;
  75                                 update->k.type          = KEY_TYPE_whiteout;
  76
  77                                 ret = bch2_trans_update(trans, &iter2, update,
  78                                                         BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
  79                         }
  80                         bch2_trans_iter_exit(trans, &iter2);
  81
  82                         if (ret)
  83                                 break;
  84
  85                         ret = snapshot_list_add(c, &s, k.k->p.snapshot);
  86                         if (ret)
  87                                 break;
  88                 }
  89         }
  90         bch2_trans_iter_exit(trans, &iter);
  91         darray_exit(&s);
  92
  93         return ret;
  94 }
  95
  96 static void trace_move_extent_finish2(struct bch_fs *c, struct bkey_s_c k)
  97 {
  98         if (trace_move_extent_finish_enabled()) {
  99                 struct printbuf buf = PRINTBUF;
 100
 101                 bch2_bkey_val_to_text(&buf, c, k);
 102                 trace_move_extent_finish(c, buf.buf);
 103                 printbuf_exit(&buf);
 104         }
 105 }
 106
 107 static void trace_move_extent_fail2(struct data_update *m,
 108                          struct bkey_s_c new,
 109                          struct bkey_s_c wrote,
 110                          struct bkey_i *insert,
 111                          const char *msg)
 112 {
 113         struct bch_fs *c = m->op.c;
 114         struct bkey_s_c old = bkey_i_to_s_c(m->k.k);
 115         const union bch_extent_entry *entry;
 116         struct bch_extent_ptr *ptr;
 117         struct extent_ptr_decoded p;
 118         struct printbuf buf = PRINTBUF;
 119         unsigned i, rewrites_found = 0;
 120
 121         if (!trace_move_extent_fail_enabled())
 122                 return;
 123
 124         prt_str(&buf, msg);
 125
 126         if (insert) {
 127                 i = 0;
 128                 bkey_for_each_ptr_decode(old.k, bch2_bkey_ptrs_c(old), p, entry) {
 129                         struct bkey_s new_s;
 130                         new_s.k = (void *) new.k;
 131                         new_s.v = (void *) new.v;
 132
 133                         if (((1U << i) & m->data_opts.rewrite_ptrs) &&
 134                             (ptr = bch2_extent_has_ptr(old, p, bkey_i_to_s(insert))) &&
 135                             !ptr->cached)
 136                                 rewrites_found |= 1U << i;
 137                         i++;
 138                 }
 139         }
 140
 141         prt_printf(&buf, "\nrewrite ptrs:   %u%u%u%u",
 142                    (m->data_opts.rewrite_ptrs & (1 << 0)) != 0,
 143                    (m->data_opts.rewrite_ptrs & (1 << 1)) != 0,
 144                    (m->data_opts.rewrite_ptrs & (1 << 2)) != 0,
 145                    (m->data_opts.rewrite_ptrs & (1 << 3)) != 0);
 146
 147         prt_printf(&buf, "\nrewrites found: %u%u%u%u",
 148                    (rewrites_found & (1 << 0)) != 0,
 149                    (rewrites_found & (1 << 1)) != 0,
 150                    (rewrites_found & (1 << 2)) != 0,
 151                    (rewrites_found & (1 << 3)) != 0);
 152
 153         prt_str(&buf, "\nold:    ");
 154         bch2_bkey_val_to_text(&buf, c, old);
 155
 156         prt_str(&buf, "\nnew:    ");
 157         bch2_bkey_val_to_text(&buf, c, new);
 158
 159         prt_str(&buf, "\nwrote:  ");
 160         bch2_bkey_val_to_text(&buf, c, wrote);
 161
 162         if (insert) {
 163                 prt_str(&buf, "\ninsert: ");
 164                 bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(insert));
 165         }
 166
 167         trace_move_extent_fail(c, buf.buf);
 168         printbuf_exit(&buf);
 169 }
 170
 171 static int __bch2_data_update_index_update(struct btree_trans *trans,
 172                                            struct bch_write_op *op)
 173 {
 174         struct bch_fs *c = op->c;
 175         struct btree_iter iter;
 176         struct data_update *m =
 177                 container_of(op, struct data_update, op);
 178         struct keylist *keys = &op->insert_keys;
 179         struct bkey_buf _new, _insert;
 180         int ret = 0;
 181
 182         bch2_bkey_buf_init(&_new);
 183         bch2_bkey_buf_init(&_insert);
 184         bch2_bkey_buf_realloc(&_insert, c, U8_MAX);
 185
 186         bch2_trans_iter_init(trans, &iter, m->btree_id,
 187                              bkey_start_pos(&bch2_keylist_front(keys)->k),
 188                              BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
 189
 190         while (1) {
 191                 struct bkey_s_c k;
 192                 struct bkey_s_c old = bkey_i_to_s_c(m->k.k);
 193                 struct bkey_i *insert = NULL;
 194                 struct bkey_i_extent *new;
 195                 const union bch_extent_entry *entry_c;
 196                 union bch_extent_entry *entry;
 197                 struct extent_ptr_decoded p;
 198                 struct bch_extent_ptr *ptr;
 199                 const struct bch_extent_ptr *ptr_c;
 200                 struct bpos next_pos;
 201                 bool should_check_enospc;
 202                 s64 i_sectors_delta = 0, disk_sectors_delta = 0;
 203                 unsigned rewrites_found = 0, durability, i;
 204
 205                 bch2_trans_begin(trans);
 206
 207                 k = bch2_btree_iter_peek_slot(&iter);
 208                 ret = bkey_err(k);
 209                 if (ret)
 210                         goto err;
 211
 212                 new = bkey_i_to_extent(bch2_keylist_front(keys));
 213
 214                 if (!bch2_extents_match(k, old)) {
 215                         trace_move_extent_fail2(m, k, bkey_i_to_s_c(&new->k_i),
 216                                                 NULL, "no match:");
 217                         goto nowork;
 218                 }
 219
 220                 bkey_reassemble(_insert.k, k);
 221                 insert = _insert.k;
 222
 223                 bch2_bkey_buf_copy(&_new, c, bch2_keylist_front(keys));
 224                 new = bkey_i_to_extent(_new.k);
 225                 bch2_cut_front(iter.pos, &new->k_i);
 226
 227                 bch2_cut_front(iter.pos,        insert);
 228                 bch2_cut_back(new->k.p,         insert);
 229                 bch2_cut_back(insert->k.p,      &new->k_i);
 230
 231                 /*
 232                  * @old: extent that we read from
 233                  * @insert: key that we're going to update, initialized from
 234                  * extent currently in btree - same as @old unless we raced with
 235                  * other updates
 236                  * @new: extent with new pointers that we'll be adding to @insert
 237                  *
 238                  * Fist, drop rewrite_ptrs from @new:
 239                  */
 240                 i = 0;
 241                 bkey_for_each_ptr_decode(old.k, bch2_bkey_ptrs_c(old), p, entry_c) {
 242                         if (((1U << i) & m->data_opts.rewrite_ptrs) &&
 243                             (ptr = bch2_extent_has_ptr(old, p, bkey_i_to_s(insert))) &&
 244                             !ptr->cached) {
 245                                 bch2_bkey_drop_ptr_noerror(bkey_i_to_s(insert), ptr);
 246                                 /*
 247                                  * See comment below:
 248                                 bch2_extent_ptr_set_cached(bkey_i_to_s(insert), ptr);
 249                                 */
 250                                 rewrites_found |= 1U << i;
 251                         }
 252                         i++;
 253                 }
 254
 255                 if (m->data_opts.rewrite_ptrs &&
 256                     !rewrites_found &&
 257                     bch2_bkey_durability(c, k) >= m->op.opts.data_replicas) {
 258                         trace_move_extent_fail2(m, k, bkey_i_to_s_c(&new->k_i), insert, "no rewrites found:");
 259                         goto nowork;
 260                 }
 261
 262                 /*
 263                  * A replica that we just wrote might conflict with a replica
 264                  * that we want to keep, due to racing with another move:
 265                  */
 266 restart_drop_conflicting_replicas:
 267                 extent_for_each_ptr(extent_i_to_s(new), ptr)
 268                         if ((ptr_c = bch2_bkey_has_device_c(bkey_i_to_s_c(insert), ptr->dev)) &&
 269                             !ptr_c->cached) {
 270                                 bch2_bkey_drop_ptr_noerror(bkey_i_to_s(&new->k_i), ptr);
 271                                 goto restart_drop_conflicting_replicas;
 272                         }
 273
 274                 if (!bkey_val_u64s(&new->k)) {
 275                         trace_move_extent_fail2(m, k, bkey_i_to_s_c(&new->k_i), insert, "new replicas conflicted:");
 276                         goto nowork;
 277                 }
 278
 279                 /* Now, drop pointers that conflict with what we just wrote: */
 280                 extent_for_each_ptr_decode(extent_i_to_s(new), p, entry)
 281                         if ((ptr = bch2_bkey_has_device(bkey_i_to_s(insert), p.ptr.dev)))
 282                                 bch2_bkey_drop_ptr_noerror(bkey_i_to_s(insert), ptr);
 283
 284                 durability = bch2_bkey_durability(c, bkey_i_to_s_c(insert)) +
 285                         bch2_bkey_durability(c, bkey_i_to_s_c(&new->k_i));
 286
 287                 /* Now, drop excess replicas: */
 288 restart_drop_extra_replicas:
 289                 bkey_for_each_ptr_decode(old.k, bch2_bkey_ptrs(bkey_i_to_s(insert)), p, entry) {
 290                         unsigned ptr_durability = bch2_extent_ptr_durability(c, &p);
 291
 292                         if (!p.ptr.cached &&
 293                             durability - ptr_durability >= m->op.opts.data_replicas) {
 294                                 durability -= ptr_durability;
 295                                 bch2_bkey_drop_ptr_noerror(bkey_i_to_s(insert), &entry->ptr);
 296                                 /*
 297                                  * Currently, we're dropping unneeded replicas
 298                                  * instead of marking them as cached, since
 299                                  * cached data in stripe buckets prevents them
 300                                  * from being reused:
 301                                 bch2_extent_ptr_set_cached(bkey_i_to_s(insert), &entry->ptr);
 302                                 */
 303                                 goto restart_drop_extra_replicas;
 304                         }
 305                 }
 306
 307                 /* Finally, add the pointers we just wrote: */
 308                 extent_for_each_ptr_decode(extent_i_to_s(new), p, entry)
 309                         bch2_extent_ptr_decoded_append(insert, &p);
 310
 311                 bch2_bkey_narrow_crcs(insert, (struct bch_extent_crc_unpacked) { 0 });
 312                 bch2_extent_normalize(c, bkey_i_to_s(insert));
 313
 314                 ret = bch2_sum_sector_overwrites(trans, &iter, insert,
 315                                                  &should_check_enospc,
 316                                                  &i_sectors_delta,
 317                                                  &disk_sectors_delta);
 318                 if (ret)
 319                         goto err;
 320
 321                 if (disk_sectors_delta > (s64) op->res.sectors) {
 322                         ret = bch2_disk_reservation_add(c, &op->res,
 323                                                 disk_sectors_delta - op->res.sectors,
 324                                                 !should_check_enospc
 325                                                 ? BCH_DISK_RESERVATION_NOFAIL : 0);
 326                         if (ret)
 327                                 goto out;
 328                 }
 329
 330                 next_pos = insert->k.p;
 331
 332                 if (!bkey_eq(bkey_start_pos(&insert->k), bkey_start_pos(k.k))) {
 333                         ret = insert_snapshot_whiteouts(trans, m->btree_id, k.k->p,
 334                                                         bkey_start_pos(&insert->k));
 335                         if (ret)
 336                                 goto err;
 337                 }
 338
 339                 if (!bkey_eq(insert->k.p, k.k->p)) {
 340                         ret = insert_snapshot_whiteouts(trans, m->btree_id,
 341                                                         k.k->p, insert->k.p);
 342                         if (ret)
 343                                 goto err;
 344                 }
 345
 346                 ret   = bch2_trans_update(trans, &iter, insert,
 347                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?:
 348                         bch2_trans_commit(trans, &op->res,
 349                                 NULL,
 350                                 BTREE_INSERT_NOCHECK_RW|
 351                                 BTREE_INSERT_NOFAIL|
 352                                 m->data_opts.btree_insert_flags);
 353                 if (!ret) {
 354                         bch2_btree_iter_set_pos(&iter, next_pos);
 355
 356                         this_cpu_add(c->counters[BCH_COUNTER_move_extent_finish], new->k.size);
 357                         trace_move_extent_finish2(c, bkey_i_to_s_c(&new->k_i));
 358                 }
 359 err:
 360                 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 361                         ret = 0;
 362                 if (ret)
 363                         break;
 364 next:
 365                 while (bkey_ge(iter.pos, bch2_keylist_front(keys)->k.p)) {
 366                         bch2_keylist_pop_front(keys);
 367                         if (bch2_keylist_empty(keys))
 368                                 goto out;
 369                 }
 370                 continue;
 371 nowork:
 372                 if (m->ctxt && m->ctxt->stats) {
 373                         BUG_ON(k.k->p.offset <= iter.pos.offset);
 374                         atomic64_inc(&m->ctxt->stats->keys_raced);
 375                         atomic64_add(k.k->p.offset - iter.pos.offset,
 376                                      &m->ctxt->stats->sectors_raced);
 377                 }
 378
 379                 this_cpu_add(c->counters[BCH_COUNTER_move_extent_fail], new->k.size);
 380
 381                 bch2_btree_iter_advance(&iter);
 382                 goto next;
 383         }
 384 out:
 385         bch2_trans_iter_exit(trans, &iter);
 386         bch2_bkey_buf_exit(&_insert, c);
 387         bch2_bkey_buf_exit(&_new, c);
 388         BUG_ON(bch2_err_matches(ret, BCH_ERR_transaction_restart));
 389         return ret;
 390 }
 391
 392 int bch2_data_update_index_update(struct bch_write_op *op)
 393 {
 394         return bch2_trans_run(op->c, __bch2_data_update_index_update(&trans, op));
 395 }
 396
 397 void bch2_data_update_read_done(struct data_update *m,
 398                                 struct bch_extent_crc_unpacked crc)
 399 {
 400         /* write bio must own pages: */
 401         BUG_ON(!m->op.wbio.bio.bi_vcnt);
 402
 403         m->op.crc = crc;
 404         m->op.wbio.bio.bi_iter.bi_size = crc.compressed_size << 9;
 405
 406         closure_call(&m->op.cl, bch2_write, NULL, NULL);
 407 }
 408
 409 void bch2_data_update_exit(struct data_update *update)
 410 {
 411         struct bch_fs *c = update->op.c;
 412         struct bkey_ptrs_c ptrs =
 413                 bch2_bkey_ptrs_c(bkey_i_to_s_c(update->k.k));
 414         const struct bch_extent_ptr *ptr;
 415
 416         bkey_for_each_ptr(ptrs, ptr) {
 417                 if (c->opts.nocow_enabled)
 418                         bch2_bucket_nocow_unlock(&c->nocow_locks,
 419                                                  PTR_BUCKET_POS(c, ptr), 0);
 420                 percpu_ref_put(&bch_dev_bkey_exists(c, ptr->dev)->ref);
 421         }
 422
 423         bch2_bkey_buf_exit(&update->k, c);
 424         bch2_disk_reservation_put(c, &update->op.res);
 425         bch2_bio_free_pages_pool(c, &update->op.wbio.bio);
 426 }
 427
 428 void bch2_update_unwritten_extent(struct btree_trans *trans,
 429                                   struct data_update *update)
 430 {
 431         struct bch_fs *c = update->op.c;
 432         struct bio *bio = &update->op.wbio.bio;
 433         struct bkey_i_extent *e;
 434         struct write_point *wp;
 435         struct bch_extent_ptr *ptr;
 436         struct closure cl;
 437         struct btree_iter iter;
 438         struct bkey_s_c k;
 439         int ret;
 440
 441         closure_init_stack(&cl);
 442         bch2_keylist_init(&update->op.insert_keys, update->op.inline_keys);
 443
 444         while (bio_sectors(bio)) {
 445                 unsigned sectors = bio_sectors(bio);
 446
 447                 bch2_trans_iter_init(trans, &iter, update->btree_id, update->op.pos,
 448                                      BTREE_ITER_SLOTS);
 449                 ret = lockrestart_do(trans, ({
 450                         k = bch2_btree_iter_peek_slot(&iter);
 451                         bkey_err(k);
 452                 }));
 453                 bch2_trans_iter_exit(trans, &iter);
 454
 455                 if (ret || !bch2_extents_match(k, bkey_i_to_s_c(update->k.k)))
 456                         break;
 457
 458                 e = bkey_extent_init(update->op.insert_keys.top);
 459                 e->k.p = update->op.pos;
 460
 461                 ret = bch2_alloc_sectors_start_trans(trans,
 462                                 update->op.target,
 463                                 false,
 464                                 update->op.write_point,
 465                                 &update->op.devs_have,
 466                                 update->op.nr_replicas,
 467                                 update->op.nr_replicas,
 468                                 update->op.alloc_reserve,
 469                                 0, &cl, &wp);
 470                 if (bch2_err_matches(ret, BCH_ERR_operation_blocked)) {
 471                         bch2_trans_unlock(trans);
 472                         closure_sync(&cl);
 473                         continue;
 474                 }
 475
 476                 if (ret)
 477                         return;
 478
 479                 sectors = min(sectors, wp->sectors_free);
 480
 481                 bch2_key_resize(&e->k, sectors);
 482
 483                 bch2_open_bucket_get(c, wp, &update->op.open_buckets);
 484                 bch2_alloc_sectors_append_ptrs(c, wp, &e->k_i, sectors, false);
 485                 bch2_alloc_sectors_done(c, wp);
 486
 487                 bio_advance(bio, sectors << 9);
 488                 update->op.pos.offset += sectors;
 489
 490                 extent_for_each_ptr(extent_i_to_s(e), ptr)
 491                         ptr->unwritten = true;
 492                 bch2_keylist_push(&update->op.insert_keys);
 493
 494                 ret = __bch2_data_update_index_update(trans, &update->op);
 495
 496                 bch2_open_buckets_put(c, &update->op.open_buckets);
 497
 498                 if (ret)
 499                         break;
 500         }
 501
 502         if ((atomic_read(&cl.remaining) & CLOSURE_REMAINING_MASK) != 1) {
 503                 bch2_trans_unlock(trans);
 504                 closure_sync(&cl);
 505         }
 506 }
 507
 508 int bch2_data_update_init(struct btree_trans *trans,
 509                           struct moving_context *ctxt,
 510                           struct data_update *m,
 511                           struct write_point_specifier wp,
 512                           struct bch_io_opts io_opts,
 513                           struct data_update_opts data_opts,
 514                           enum btree_id btree_id,
 515                           struct bkey_s_c k)
 516 {
 517         struct bch_fs *c = trans->c;
 518         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
 519         const union bch_extent_entry *entry;
 520         struct extent_ptr_decoded p;
 521         const struct bch_extent_ptr *ptr;
 522         unsigned i, reserve_sectors = k.k->size * data_opts.extra_replicas;
 523         unsigned ptrs_locked = 0;
 524         int ret;
 525
 526         bch2_bkey_buf_init(&m->k);
 527         bch2_bkey_buf_reassemble(&m->k, c, k);
 528         m->btree_id     = btree_id;
 529         m->data_opts    = data_opts;
 530
 531         bch2_write_op_init(&m->op, c, io_opts);
 532         m->op.pos       = bkey_start_pos(k.k);
 533         m->op.version   = k.k->version;
 534         m->op.target    = data_opts.target;
 535         m->op.write_point = wp;
 536         m->op.nr_replicas = 0;
 537         m->op.flags     |= BCH_WRITE_PAGES_STABLE|
 538                 BCH_WRITE_PAGES_OWNED|
 539                 BCH_WRITE_DATA_ENCODED|
 540                 BCH_WRITE_MOVE|
 541                 m->data_opts.write_flags;
 542         m->op.compression_type =
 543                 bch2_compression_opt_to_type[io_opts.background_compression ?:
 544                                              io_opts.compression];
 545         if (m->data_opts.btree_insert_flags & BTREE_INSERT_USE_RESERVE)
 546                 m->op.alloc_reserve = RESERVE_movinggc;
 547
 548         bkey_for_each_ptr(ptrs, ptr)
 549                 percpu_ref_get(&bch_dev_bkey_exists(c, ptr->dev)->ref);
 550
 551         i = 0;
 552         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 553                 bool locked;
 554
 555                 if (((1U << i) & m->data_opts.rewrite_ptrs)) {
 556                         BUG_ON(p.ptr.cached);
 557
 558                         if (crc_is_compressed(p.crc))
 559                                 reserve_sectors += k.k->size;
 560
 561                         m->op.nr_replicas += bch2_extent_ptr_durability(c, &p);
 562                 } else if (!p.ptr.cached) {
 563                         bch2_dev_list_add_dev(&m->op.devs_have, p.ptr.dev);
 564                 }
 565
 566                 /*
 567                  * op->csum_type is normally initialized from the fs/file's
 568                  * current options - but if an extent is encrypted, we require
 569                  * that it stays encrypted:
 570                  */
 571                 if (bch2_csum_type_is_encryption(p.crc.csum_type)) {
 572                         m->op.nonce     = p.crc.nonce + p.crc.offset;
 573                         m->op.csum_type = p.crc.csum_type;
 574                 }
 575
 576                 if (p.crc.compression_type == BCH_COMPRESSION_TYPE_incompressible)
 577                         m->op.incompressible = true;
 578
 579                 if (c->opts.nocow_enabled) {
 580                         if (ctxt) {
 581                                 move_ctxt_wait_event(ctxt, trans,
 582                                                 (locked = bch2_bucket_nocow_trylock(&c->nocow_locks,
 583                                                                           PTR_BUCKET_POS(c, &p.ptr), 0)) ||
 584                                                 !atomic_read(&ctxt->read_sectors));
 585
 586                                 if (!locked)
 587                                         bch2_bucket_nocow_lock(&c->nocow_locks,
 588                                                                PTR_BUCKET_POS(c, &p.ptr), 0);
 589                         } else {
 590                                 if (!bch2_bucket_nocow_trylock(&c->nocow_locks,
 591                                                                PTR_BUCKET_POS(c, &p.ptr), 0)) {
 592                                         ret = -BCH_ERR_nocow_lock_blocked;
 593                                         goto err;
 594                                 }
 595                         }
 596                         ptrs_locked |= (1U << i);
 597                 }
 598
 599                 i++;
 600         }
 601
 602         if (reserve_sectors) {
 603                 ret = bch2_disk_reservation_add(c, &m->op.res, reserve_sectors,
 604                                 m->data_opts.extra_replicas
 605                                 ? 0
 606                                 : BCH_DISK_RESERVATION_NOFAIL);
 607                 if (ret)
 608                         goto err;
 609         }
 610
 611         m->op.nr_replicas += m->data_opts.extra_replicas;
 612         m->op.nr_replicas_required = m->op.nr_replicas;
 613
 614         BUG_ON(!m->op.nr_replicas);
 615
 616         /* Special handling required: */
 617         if (bkey_extent_is_unwritten(k))
 618                 return -BCH_ERR_unwritten_extent_update;
 619         return 0;
 620 err:
 621         i = 0;
 622         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 623                 if ((1U << i) & ptrs_locked)
 624                         bch2_bucket_nocow_unlock(&c->nocow_locks,
 625                                                  PTR_BUCKET_POS(c, &p.ptr), 0);
 626                 percpu_ref_put(&bch_dev_bkey_exists(c, p.ptr.dev)->ref);
 627                 i++;
 628         }
 629
 630         bch2_bkey_buf_exit(&m->k, c);
 631         bch2_bio_free_pages_pool(c, &m->op.wbio.bio);
 632         return ret;
 633 }
 634
 635 void bch2_data_update_opts_normalize(struct bkey_s_c k, struct data_update_opts *opts)
 636 {
 637         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
 638         const struct bch_extent_ptr *ptr;
 639         unsigned i = 0;
 640
 641         bkey_for_each_ptr(ptrs, ptr) {
 642                 if ((opts->rewrite_ptrs & (1U << i)) && ptr->cached) {
 643                         opts->kill_ptrs |= 1U << i;
 644                         opts->rewrite_ptrs ^= 1U << i;
 645                 }
 646
 647                 i++;
 648         }
 649 }