fs/bcachefs/reflink.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "bcachefs.h"
   3 #include "bkey_buf.h"
   4 #include "btree_update.h"
   5 #include "buckets.h"
   6 #include "error.h"
   7 #include "extents.h"
   8 #include "inode.h"
   9 #include "io_misc.h"
  10 #include "io_write.h"
  11 #include "rebalance.h"
  12 #include "reflink.h"
  13 #include "subvolume.h"
  14 #include "super-io.h"
  15
  16 #include <linux/sched/signal.h>
  17
  18 static inline unsigned bkey_type_to_indirect(const struct bkey *k)
  19 {
  20         switch (k->type) {
  21         case KEY_TYPE_extent:
  22                 return KEY_TYPE_reflink_v;
  23         case KEY_TYPE_inline_data:
  24                 return KEY_TYPE_indirect_inline_data;
  25         default:
  26                 return 0;
  27         }
  28 }
  29
  30 /* reflink pointers */
  31
  32 int bch2_reflink_p_invalid(struct bch_fs *c, struct bkey_s_c k,
  33                            enum bkey_invalid_flags flags,
  34                            struct printbuf *err)
  35 {
  36         struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
  37         int ret = 0;
  38
  39         bkey_fsck_err_on(le64_to_cpu(p.v->idx) < le32_to_cpu(p.v->front_pad),
  40                          c, err, reflink_p_front_pad_bad,
  41                          "idx < front_pad (%llu < %u)",
  42                          le64_to_cpu(p.v->idx), le32_to_cpu(p.v->front_pad));
  43 fsck_err:
  44         return ret;
  45 }
  46
  47 void bch2_reflink_p_to_text(struct printbuf *out, struct bch_fs *c,
  48                             struct bkey_s_c k)
  49 {
  50         struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
  51
  52         prt_printf(out, "idx %llu front_pad %u back_pad %u",
  53                le64_to_cpu(p.v->idx),
  54                le32_to_cpu(p.v->front_pad),
  55                le32_to_cpu(p.v->back_pad));
  56 }
  57
  58 bool bch2_reflink_p_merge(struct bch_fs *c, struct bkey_s _l, struct bkey_s_c _r)
  59 {
  60         struct bkey_s_reflink_p l = bkey_s_to_reflink_p(_l);
  61         struct bkey_s_c_reflink_p r = bkey_s_c_to_reflink_p(_r);
  62
  63         /*
  64          * Disabled for now, the triggers code needs to be reworked for merging
  65          * of reflink pointers to work:
  66          */
  67         return false;
  68
  69         if (le64_to_cpu(l.v->idx) + l.k->size != le64_to_cpu(r.v->idx))
  70                 return false;
  71
  72         bch2_key_resize(l.k, l.k->size + r.k->size);
  73         return true;
  74 }
  75
  76 static int trans_trigger_reflink_p_segment(struct btree_trans *trans,
  77                         struct bkey_s_c_reflink_p p,
  78                         u64 *idx, unsigned flags)
  79 {
  80         struct bch_fs *c = trans->c;
  81         struct btree_iter iter;
  82         struct bkey_i *k;
  83         __le64 *refcount;
  84         int add = !(flags & BTREE_TRIGGER_OVERWRITE) ? 1 : -1;
  85         struct printbuf buf = PRINTBUF;
  86         int ret;
  87
  88         k = bch2_bkey_get_mut_noupdate(trans, &iter,
  89                         BTREE_ID_reflink, POS(0, *idx),
  90                         BTREE_ITER_WITH_UPDATES);
  91         ret = PTR_ERR_OR_ZERO(k);
  92         if (ret)
  93                 goto err;
  94
  95         refcount = bkey_refcount(bkey_i_to_s(k));
  96         if (!refcount) {
  97                 bch2_bkey_val_to_text(&buf, c, p.s_c);
  98                 bch2_trans_inconsistent(trans,
  99                         "nonexistent indirect extent at %llu while marking\n  %s",
 100                         *idx, buf.buf);
 101                 ret = -EIO;
 102                 goto err;
 103         }
 104
 105         if (!*refcount && (flags & BTREE_TRIGGER_OVERWRITE)) {
 106                 bch2_bkey_val_to_text(&buf, c, p.s_c);
 107                 bch2_trans_inconsistent(trans,
 108                         "indirect extent refcount underflow at %llu while marking\n  %s",
 109                         *idx, buf.buf);
 110                 ret = -EIO;
 111                 goto err;
 112         }
 113
 114         if (flags & BTREE_TRIGGER_INSERT) {
 115                 struct bch_reflink_p *v = (struct bch_reflink_p *) p.v;
 116                 u64 pad;
 117
 118                 pad = max_t(s64, le32_to_cpu(v->front_pad),
 119                             le64_to_cpu(v->idx) - bkey_start_offset(&k->k));
 120                 BUG_ON(pad > U32_MAX);
 121                 v->front_pad = cpu_to_le32(pad);
 122
 123                 pad = max_t(s64, le32_to_cpu(v->back_pad),
 124                             k->k.p.offset - p.k->size - le64_to_cpu(v->idx));
 125                 BUG_ON(pad > U32_MAX);
 126                 v->back_pad = cpu_to_le32(pad);
 127         }
 128
 129         le64_add_cpu(refcount, add);
 130
 131         bch2_btree_iter_set_pos_to_extent_start(&iter);
 132         ret = bch2_trans_update(trans, &iter, k, 0);
 133         if (ret)
 134                 goto err;
 135
 136         *idx = k->k.p.offset;
 137 err:
 138         bch2_trans_iter_exit(trans, &iter);
 139         printbuf_exit(&buf);
 140         return ret;
 141 }
 142
 143 static s64 gc_trigger_reflink_p_segment(struct btree_trans *trans,
 144                                 struct bkey_s_c_reflink_p p,
 145                                 u64 *idx, unsigned flags, size_t r_idx)
 146 {
 147         struct bch_fs *c = trans->c;
 148         struct reflink_gc *r;
 149         int add = !(flags & BTREE_TRIGGER_OVERWRITE) ? 1 : -1;
 150         u64 start = le64_to_cpu(p.v->idx);
 151         u64 end = le64_to_cpu(p.v->idx) + p.k->size;
 152         u64 next_idx = end + le32_to_cpu(p.v->back_pad);
 153         s64 ret = 0;
 154         struct printbuf buf = PRINTBUF;
 155
 156         if (r_idx >= c->reflink_gc_nr)
 157                 goto not_found;
 158
 159         r = genradix_ptr(&c->reflink_gc_table, r_idx);
 160         next_idx = min(next_idx, r->offset - r->size);
 161         if (*idx < next_idx)
 162                 goto not_found;
 163
 164         BUG_ON((s64) r->refcount + add < 0);
 165
 166         r->refcount += add;
 167         *idx = r->offset;
 168         return 0;
 169 not_found:
 170         if (fsck_err(c, reflink_p_to_missing_reflink_v,
 171                      "pointer to missing indirect extent\n"
 172                      "  %s\n"
 173                      "  missing range %llu-%llu",
 174                      (bch2_bkey_val_to_text(&buf, c, p.s_c), buf.buf),
 175                      *idx, next_idx)) {
 176                 struct bkey_i *update = bch2_bkey_make_mut_noupdate(trans, p.s_c);
 177                 ret = PTR_ERR_OR_ZERO(update);
 178                 if (ret)
 179                         goto err;
 180
 181                 if (next_idx <= start) {
 182                         bkey_i_to_reflink_p(update)->v.front_pad = cpu_to_le32(start - next_idx);
 183                 } else if (*idx >= end) {
 184                         bkey_i_to_reflink_p(update)->v.back_pad = cpu_to_le32(*idx - end);
 185                 } else {
 186                         bkey_error_init(update);
 187                         update->k.p             = p.k->p;
 188                         update->k.p.offset      = next_idx;
 189                         update->k.size          = next_idx - *idx;
 190                         set_bkey_val_u64s(&update->k, 0);
 191                 }
 192
 193                 ret = bch2_btree_insert_trans(trans, BTREE_ID_extents, update, BTREE_TRIGGER_NORUN);
 194         }
 195
 196         *idx = next_idx;
 197 err:
 198 fsck_err:
 199         printbuf_exit(&buf);
 200         return ret;
 201 }
 202
 203 static int __trigger_reflink_p(struct btree_trans *trans,
 204                             enum btree_id btree_id, unsigned level,
 205                             struct bkey_s_c k, unsigned flags)
 206 {
 207         struct bch_fs *c = trans->c;
 208         struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
 209         int ret = 0;
 210
 211         u64 idx = le64_to_cpu(p.v->idx) - le32_to_cpu(p.v->front_pad);
 212         u64 end = le64_to_cpu(p.v->idx) + p.k->size + le32_to_cpu(p.v->back_pad);
 213
 214         if (flags & BTREE_TRIGGER_TRANSACTIONAL) {
 215                 while (idx < end && !ret)
 216                         ret = trans_trigger_reflink_p_segment(trans, p, &idx, flags);
 217         }
 218
 219         if (flags & BTREE_TRIGGER_GC) {
 220                 size_t l = 0, r = c->reflink_gc_nr;
 221
 222                 while (l < r) {
 223                         size_t m = l + (r - l) / 2;
 224                         struct reflink_gc *ref = genradix_ptr(&c->reflink_gc_table, m);
 225                         if (ref->offset <= idx)
 226                                 l = m + 1;
 227                         else
 228                                 r = m;
 229                 }
 230
 231                 while (idx < end && !ret)
 232                         ret = gc_trigger_reflink_p_segment(trans, p, &idx, flags, l++);
 233         }
 234
 235         return ret;
 236 }
 237
 238 int bch2_trigger_reflink_p(struct btree_trans *trans,
 239                            enum btree_id btree_id, unsigned level,
 240                            struct bkey_s_c old,
 241                            struct bkey_s new,
 242                            unsigned flags)
 243 {
 244         if ((flags & BTREE_TRIGGER_TRANSACTIONAL) &&
 245             (flags & BTREE_TRIGGER_INSERT)) {
 246                 struct bch_reflink_p *v = bkey_s_to_reflink_p(new).v;
 247
 248                 v->front_pad = v->back_pad = 0;
 249         }
 250
 251         return trigger_run_overwrite_then_insert(__trigger_reflink_p, trans, btree_id, level, old, new, flags);
 252 }
 253
 254 /* indirect extents */
 255
 256 int bch2_reflink_v_invalid(struct bch_fs *c, struct bkey_s_c k,
 257                            enum bkey_invalid_flags flags,
 258                            struct printbuf *err)
 259 {
 260         return bch2_bkey_ptrs_invalid(c, k, flags, err);
 261 }
 262
 263 void bch2_reflink_v_to_text(struct printbuf *out, struct bch_fs *c,
 264                             struct bkey_s_c k)
 265 {
 266         struct bkey_s_c_reflink_v r = bkey_s_c_to_reflink_v(k);
 267
 268         prt_printf(out, "refcount: %llu ", le64_to_cpu(r.v->refcount));
 269
 270         bch2_bkey_ptrs_to_text(out, c, k);
 271 }
 272
 273 #if 0
 274 Currently disabled, needs to be debugged:
 275
 276 bool bch2_reflink_v_merge(struct bch_fs *c, struct bkey_s _l, struct bkey_s_c _r)
 277 {
 278         struct bkey_s_reflink_v   l = bkey_s_to_reflink_v(_l);
 279         struct bkey_s_c_reflink_v r = bkey_s_c_to_reflink_v(_r);
 280
 281         return l.v->refcount == r.v->refcount && bch2_extent_merge(c, _l, _r);
 282 }
 283 #endif
 284
 285 static inline void check_indirect_extent_deleting(struct bkey_s new, unsigned *flags)
 286 {
 287         if ((*flags & BTREE_TRIGGER_INSERT) && !*bkey_refcount(new)) {
 288                 new.k->type = KEY_TYPE_deleted;
 289                 new.k->size = 0;
 290                 set_bkey_val_u64s(new.k, 0);
 291                 *flags &= ~BTREE_TRIGGER_INSERT;
 292         }
 293 }
 294
 295 int bch2_trigger_reflink_v(struct btree_trans *trans,
 296                            enum btree_id btree_id, unsigned level,
 297                            struct bkey_s_c old, struct bkey_s new,
 298                            unsigned flags)
 299 {
 300         if ((flags & BTREE_TRIGGER_TRANSACTIONAL) &&
 301             (flags & BTREE_TRIGGER_INSERT))
 302                 check_indirect_extent_deleting(new, &flags);
 303
 304         return bch2_trigger_extent(trans, btree_id, level, old, new, flags);
 305 }
 306
 307 /* indirect inline data */
 308
 309 int bch2_indirect_inline_data_invalid(struct bch_fs *c, struct bkey_s_c k,
 310                                       enum bkey_invalid_flags flags,
 311                                       struct printbuf *err)
 312 {
 313         return 0;
 314 }
 315
 316 void bch2_indirect_inline_data_to_text(struct printbuf *out,
 317                                        struct bch_fs *c, struct bkey_s_c k)
 318 {
 319         struct bkey_s_c_indirect_inline_data d = bkey_s_c_to_indirect_inline_data(k);
 320         unsigned datalen = bkey_inline_data_bytes(k.k);
 321
 322         prt_printf(out, "refcount %llu datalen %u: %*phN",
 323                le64_to_cpu(d.v->refcount), datalen,
 324                min(datalen, 32U), d.v->data);
 325 }
 326
 327 int bch2_trigger_indirect_inline_data(struct btree_trans *trans,
 328                               enum btree_id btree_id, unsigned level,
 329                               struct bkey_s_c old, struct bkey_s new,
 330                               unsigned flags)
 331 {
 332         check_indirect_extent_deleting(new, &flags);
 333
 334         return 0;
 335 }
 336
 337 static int bch2_make_extent_indirect(struct btree_trans *trans,
 338                                      struct btree_iter *extent_iter,
 339                                      struct bkey_i *orig)
 340 {
 341         struct bch_fs *c = trans->c;
 342         struct btree_iter reflink_iter = { NULL };
 343         struct bkey_s_c k;
 344         struct bkey_i *r_v;
 345         struct bkey_i_reflink_p *r_p;
 346         __le64 *refcount;
 347         int ret;
 348
 349         if (orig->k.type == KEY_TYPE_inline_data)
 350                 bch2_check_set_feature(c, BCH_FEATURE_reflink_inline_data);
 351
 352         bch2_trans_iter_init(trans, &reflink_iter, BTREE_ID_reflink, POS_MAX,
 353                              BTREE_ITER_INTENT);
 354         k = bch2_btree_iter_peek_prev(&reflink_iter);
 355         ret = bkey_err(k);
 356         if (ret)
 357                 goto err;
 358
 359         r_v = bch2_trans_kmalloc(trans, sizeof(__le64) + bkey_bytes(&orig->k));
 360         ret = PTR_ERR_OR_ZERO(r_v);
 361         if (ret)
 362                 goto err;
 363
 364         bkey_init(&r_v->k);
 365         r_v->k.type     = bkey_type_to_indirect(&orig->k);
 366         r_v->k.p        = reflink_iter.pos;
 367         bch2_key_resize(&r_v->k, orig->k.size);
 368         r_v->k.version  = orig->k.version;
 369
 370         set_bkey_val_bytes(&r_v->k, sizeof(__le64) + bkey_val_bytes(&orig->k));
 371
 372         refcount        = bkey_refcount(bkey_i_to_s(r_v));
 373         *refcount       = 0;
 374         memcpy(refcount + 1, &orig->v, bkey_val_bytes(&orig->k));
 375
 376         ret = bch2_trans_update(trans, &reflink_iter, r_v, 0);
 377         if (ret)
 378                 goto err;
 379
 380         /*
 381          * orig is in a bkey_buf which statically allocates 5 64s for the val,
 382          * so we know it will be big enough:
 383          */
 384         orig->k.type = KEY_TYPE_reflink_p;
 385         r_p = bkey_i_to_reflink_p(orig);
 386         set_bkey_val_bytes(&r_p->k, sizeof(r_p->v));
 387
 388         /* FORTIFY_SOURCE is broken here, and doesn't provide unsafe_memset() */
 389 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
 390         __underlying_memset(&r_p->v, 0, sizeof(r_p->v));
 391 #else
 392         memset(&r_p->v, 0, sizeof(r_p->v));
 393 #endif
 394
 395         r_p->v.idx = cpu_to_le64(bkey_start_offset(&r_v->k));
 396
 397         ret = bch2_trans_update(trans, extent_iter, &r_p->k_i,
 398                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
 399 err:
 400         bch2_trans_iter_exit(trans, &reflink_iter);
 401
 402         return ret;
 403 }
 404
 405 static struct bkey_s_c get_next_src(struct btree_iter *iter, struct bpos end)
 406 {
 407         struct bkey_s_c k;
 408         int ret;
 409
 410         for_each_btree_key_upto_continue_norestart(*iter, end, 0, k, ret) {
 411                 if (bkey_extent_is_unwritten(k))
 412                         continue;
 413
 414                 if (bkey_extent_is_data(k.k))
 415                         return k;
 416         }
 417
 418         if (bkey_ge(iter->pos, end))
 419                 bch2_btree_iter_set_pos(iter, end);
 420         return ret ? bkey_s_c_err(ret) : bkey_s_c_null;
 421 }
 422
 423 s64 bch2_remap_range(struct bch_fs *c,
 424                      subvol_inum dst_inum, u64 dst_offset,
 425                      subvol_inum src_inum, u64 src_offset,
 426                      u64 remap_sectors,
 427                      u64 new_i_size, s64 *i_sectors_delta)
 428 {
 429         struct btree_trans *trans;
 430         struct btree_iter dst_iter, src_iter;
 431         struct bkey_s_c src_k;
 432         struct bkey_buf new_dst, new_src;
 433         struct bpos dst_start = POS(dst_inum.inum, dst_offset);
 434         struct bpos src_start = POS(src_inum.inum, src_offset);
 435         struct bpos dst_end = dst_start, src_end = src_start;
 436         struct bch_io_opts opts;
 437         struct bpos src_want;
 438         u64 dst_done = 0;
 439         u32 dst_snapshot, src_snapshot;
 440         int ret = 0, ret2 = 0;
 441
 442         if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_reflink))
 443                 return -BCH_ERR_erofs_no_writes;
 444
 445         bch2_check_set_feature(c, BCH_FEATURE_reflink);
 446
 447         dst_end.offset += remap_sectors;
 448         src_end.offset += remap_sectors;
 449
 450         bch2_bkey_buf_init(&new_dst);
 451         bch2_bkey_buf_init(&new_src);
 452         trans = bch2_trans_get(c);
 453
 454         ret = bch2_inum_opts_get(trans, src_inum, &opts);
 455         if (ret)
 456                 goto err;
 457
 458         bch2_trans_iter_init(trans, &src_iter, BTREE_ID_extents, src_start,
 459                              BTREE_ITER_INTENT);
 460         bch2_trans_iter_init(trans, &dst_iter, BTREE_ID_extents, dst_start,
 461                              BTREE_ITER_INTENT);
 462
 463         while ((ret == 0 ||
 464                 bch2_err_matches(ret, BCH_ERR_transaction_restart)) &&
 465                bkey_lt(dst_iter.pos, dst_end)) {
 466                 struct disk_reservation disk_res = { 0 };
 467
 468                 bch2_trans_begin(trans);
 469
 470                 if (fatal_signal_pending(current)) {
 471                         ret = -EINTR;
 472                         break;
 473                 }
 474
 475                 ret = bch2_subvolume_get_snapshot(trans, src_inum.subvol,
 476                                                   &src_snapshot);
 477                 if (ret)
 478                         continue;
 479
 480                 bch2_btree_iter_set_snapshot(&src_iter, src_snapshot);
 481
 482                 ret = bch2_subvolume_get_snapshot(trans, dst_inum.subvol,
 483                                                   &dst_snapshot);
 484                 if (ret)
 485                         continue;
 486
 487                 bch2_btree_iter_set_snapshot(&dst_iter, dst_snapshot);
 488
 489                 if (dst_inum.inum < src_inum.inum) {
 490                         /* Avoid some lock cycle transaction restarts */
 491                         ret = bch2_btree_iter_traverse(&dst_iter);
 492                         if (ret)
 493                                 continue;
 494                 }
 495
 496                 dst_done = dst_iter.pos.offset - dst_start.offset;
 497                 src_want = POS(src_start.inode, src_start.offset + dst_done);
 498                 bch2_btree_iter_set_pos(&src_iter, src_want);
 499
 500                 src_k = get_next_src(&src_iter, src_end);
 501                 ret = bkey_err(src_k);
 502                 if (ret)
 503                         continue;
 504
 505                 if (bkey_lt(src_want, src_iter.pos)) {
 506                         ret = bch2_fpunch_at(trans, &dst_iter, dst_inum,
 507                                         min(dst_end.offset,
 508                                             dst_iter.pos.offset +
 509                                             src_iter.pos.offset - src_want.offset),
 510                                         i_sectors_delta);
 511                         continue;
 512                 }
 513
 514                 if (src_k.k->type != KEY_TYPE_reflink_p) {
 515                         bch2_btree_iter_set_pos_to_extent_start(&src_iter);
 516
 517                         bch2_bkey_buf_reassemble(&new_src, c, src_k);
 518                         src_k = bkey_i_to_s_c(new_src.k);
 519
 520                         ret = bch2_make_extent_indirect(trans, &src_iter,
 521                                                 new_src.k);
 522                         if (ret)
 523                                 continue;
 524
 525                         BUG_ON(src_k.k->type != KEY_TYPE_reflink_p);
 526                 }
 527
 528                 if (src_k.k->type == KEY_TYPE_reflink_p) {
 529                         struct bkey_s_c_reflink_p src_p =
 530                                 bkey_s_c_to_reflink_p(src_k);
 531                         struct bkey_i_reflink_p *dst_p =
 532                                 bkey_reflink_p_init(new_dst.k);
 533
 534                         u64 offset = le64_to_cpu(src_p.v->idx) +
 535                                 (src_want.offset -
 536                                  bkey_start_offset(src_k.k));
 537
 538                         dst_p->v.idx = cpu_to_le64(offset);
 539                 } else {
 540                         BUG();
 541                 }
 542
 543                 new_dst.k->k.p = dst_iter.pos;
 544                 bch2_key_resize(&new_dst.k->k,
 545                                 min(src_k.k->p.offset - src_want.offset,
 546                                     dst_end.offset - dst_iter.pos.offset));
 547
 548                 ret =   bch2_bkey_set_needs_rebalance(c, new_dst.k,
 549                                         opts.background_target,
 550                                         opts.background_compression) ?:
 551                         bch2_extent_update(trans, dst_inum, &dst_iter,
 552                                         new_dst.k, &disk_res,
 553                                         new_i_size, i_sectors_delta,
 554                                         true);
 555                 bch2_disk_reservation_put(c, &disk_res);
 556         }
 557         bch2_trans_iter_exit(trans, &dst_iter);
 558         bch2_trans_iter_exit(trans, &src_iter);
 559
 560         BUG_ON(!ret && !bkey_eq(dst_iter.pos, dst_end));
 561         BUG_ON(bkey_gt(dst_iter.pos, dst_end));
 562
 563         dst_done = dst_iter.pos.offset - dst_start.offset;
 564         new_i_size = min(dst_iter.pos.offset << 9, new_i_size);
 565
 566         do {
 567                 struct bch_inode_unpacked inode_u;
 568                 struct btree_iter inode_iter = { NULL };
 569
 570                 bch2_trans_begin(trans);
 571
 572                 ret2 = bch2_inode_peek(trans, &inode_iter, &inode_u,
 573                                        dst_inum, BTREE_ITER_INTENT);
 574
 575                 if (!ret2 &&
 576                     inode_u.bi_size < new_i_size) {
 577                         inode_u.bi_size = new_i_size;
 578                         ret2  = bch2_inode_write(trans, &inode_iter, &inode_u) ?:
 579                                 bch2_trans_commit(trans, NULL, NULL,
 580                                                   BCH_TRANS_COMMIT_no_enospc);
 581                 }
 582
 583                 bch2_trans_iter_exit(trans, &inode_iter);
 584         } while (bch2_err_matches(ret2, BCH_ERR_transaction_restart));
 585 err:
 586         bch2_trans_put(trans);
 587         bch2_bkey_buf_exit(&new_src, c);
 588         bch2_bkey_buf_exit(&new_dst, c);
 589
 590         bch2_write_ref_put(c, BCH_WRITE_REF_reflink);
 591
 592         return dst_done ?: ret ?: ret2;
 593 }