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_validate(struct bch_fs *c, struct bkey_s_c k,
  33                             enum bch_validate_flags flags)
  34 {
  35         struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
  36         int ret = 0;
  37
  38         bkey_fsck_err_on(le64_to_cpu(p.v->idx) < le32_to_cpu(p.v->front_pad),
  39                          c, reflink_p_front_pad_bad,
  40                          "idx < front_pad (%llu < %u)",
  41                          le64_to_cpu(p.v->idx), le32_to_cpu(p.v->front_pad));
  42 fsck_err:
  43         return ret;
  44 }
  45
  46 void bch2_reflink_p_to_text(struct printbuf *out, struct bch_fs *c,
  47                             struct bkey_s_c k)
  48 {
  49         struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
  50
  51         prt_printf(out, "idx %llu front_pad %u back_pad %u",
  52                le64_to_cpu(p.v->idx),
  53                le32_to_cpu(p.v->front_pad),
  54                le32_to_cpu(p.v->back_pad));
  55 }
  56
  57 bool bch2_reflink_p_merge(struct bch_fs *c, struct bkey_s _l, struct bkey_s_c _r)
  58 {
  59         struct bkey_s_reflink_p l = bkey_s_to_reflink_p(_l);
  60         struct bkey_s_c_reflink_p r = bkey_s_c_to_reflink_p(_r);
  61
  62         /*
  63          * Disabled for now, the triggers code needs to be reworked for merging
  64          * of reflink pointers to work:
  65          */
  66         return false;
  67
  68         if (le64_to_cpu(l.v->idx) + l.k->size != le64_to_cpu(r.v->idx))
  69                 return false;
  70
  71         bch2_key_resize(l.k, l.k->size + r.k->size);
  72         return true;
  73 }
  74
  75 static int trans_trigger_reflink_p_segment(struct btree_trans *trans,
  76                         struct bkey_s_c_reflink_p p, u64 *idx,
  77                         enum btree_iter_update_trigger_flags flags)
  78 {
  79         struct bch_fs *c = trans->c;
  80         struct btree_iter iter;
  81         struct bkey_i *k;
  82         __le64 *refcount;
  83         int add = !(flags & BTREE_TRIGGER_overwrite) ? 1 : -1;
  84         struct printbuf buf = PRINTBUF;
  85         int ret;
  86
  87         k = bch2_bkey_get_mut_noupdate(trans, &iter,
  88                         BTREE_ID_reflink, POS(0, *idx),
  89                         BTREE_ITER_with_updates);
  90         ret = PTR_ERR_OR_ZERO(k);
  91         if (ret)
  92                 goto err;
  93
  94         refcount = bkey_refcount(bkey_i_to_s(k));
  95         if (!refcount) {
  96                 bch2_bkey_val_to_text(&buf, c, p.s_c);
  97                 bch2_trans_inconsistent(trans,
  98                         "nonexistent indirect extent at %llu while marking\n  %s",
  99                         *idx, buf.buf);
 100                 ret = -EIO;
 101                 goto err;
 102         }
 103
 104         if (!*refcount && (flags & BTREE_TRIGGER_overwrite)) {
 105                 bch2_bkey_val_to_text(&buf, c, p.s_c);
 106                 bch2_trans_inconsistent(trans,
 107                         "indirect extent refcount underflow at %llu while marking\n  %s",
 108                         *idx, buf.buf);
 109                 ret = -EIO;
 110                 goto err;
 111         }
 112
 113         if (flags & BTREE_TRIGGER_insert) {
 114                 struct bch_reflink_p *v = (struct bch_reflink_p *) p.v;
 115                 u64 pad;
 116
 117                 pad = max_t(s64, le32_to_cpu(v->front_pad),
 118                             le64_to_cpu(v->idx) - bkey_start_offset(&k->k));
 119                 BUG_ON(pad > U32_MAX);
 120                 v->front_pad = cpu_to_le32(pad);
 121
 122                 pad = max_t(s64, le32_to_cpu(v->back_pad),
 123                             k->k.p.offset - p.k->size - le64_to_cpu(v->idx));
 124                 BUG_ON(pad > U32_MAX);
 125                 v->back_pad = cpu_to_le32(pad);
 126         }
 127
 128         le64_add_cpu(refcount, add);
 129
 130         bch2_btree_iter_set_pos_to_extent_start(&iter);
 131         ret = bch2_trans_update(trans, &iter, k, 0);
 132         if (ret)
 133                 goto err;
 134
 135         *idx = k->k.p.offset;
 136 err:
 137         bch2_trans_iter_exit(trans, &iter);
 138         printbuf_exit(&buf);
 139         return ret;
 140 }
 141
 142 static s64 gc_trigger_reflink_p_segment(struct btree_trans *trans,
 143                                 struct bkey_s_c_reflink_p p, u64 *idx,
 144                                 enum btree_iter_update_trigger_flags flags,
 145                                 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         if (flags & BTREE_TRIGGER_gc)
 167                 r->refcount += add;
 168         *idx = r->offset;
 169         return 0;
 170 not_found:
 171         BUG_ON(!(flags & BTREE_TRIGGER_check_repair));
 172
 173         if (fsck_err(trans, reflink_p_to_missing_reflink_v,
 174                      "pointer to missing indirect extent\n"
 175                      "  %s\n"
 176                      "  missing range %llu-%llu",
 177                      (bch2_bkey_val_to_text(&buf, c, p.s_c), buf.buf),
 178                      *idx, next_idx)) {
 179                 struct bkey_i *update = bch2_bkey_make_mut_noupdate(trans, p.s_c);
 180                 ret = PTR_ERR_OR_ZERO(update);
 181                 if (ret)
 182                         goto err;
 183
 184                 if (next_idx <= start) {
 185                         bkey_i_to_reflink_p(update)->v.front_pad = cpu_to_le32(start - next_idx);
 186                 } else if (*idx >= end) {
 187                         bkey_i_to_reflink_p(update)->v.back_pad = cpu_to_le32(*idx - end);
 188                 } else {
 189                         bkey_error_init(update);
 190                         update->k.p             = p.k->p;
 191                         update->k.size          = p.k->size;
 192                         set_bkey_val_u64s(&update->k, 0);
 193                 }
 194
 195                 ret = bch2_btree_insert_trans(trans, BTREE_ID_extents, update, BTREE_TRIGGER_norun);
 196         }
 197
 198         *idx = next_idx;
 199 err:
 200 fsck_err:
 201         printbuf_exit(&buf);
 202         return ret;
 203 }
 204
 205 static int __trigger_reflink_p(struct btree_trans *trans,
 206                 enum btree_id btree_id, unsigned level, struct bkey_s_c k,
 207                 enum btree_iter_update_trigger_flags flags)
 208 {
 209         struct bch_fs *c = trans->c;
 210         struct bkey_s_c_reflink_p p = bkey_s_c_to_reflink_p(k);
 211         int ret = 0;
 212
 213         u64 idx = le64_to_cpu(p.v->idx) - le32_to_cpu(p.v->front_pad);
 214         u64 end = le64_to_cpu(p.v->idx) + p.k->size + le32_to_cpu(p.v->back_pad);
 215
 216         if (flags & BTREE_TRIGGER_transactional) {
 217                 while (idx < end && !ret)
 218                         ret = trans_trigger_reflink_p_segment(trans, p, &idx, flags);
 219         }
 220
 221         if (flags & (BTREE_TRIGGER_check_repair|BTREE_TRIGGER_gc)) {
 222                 size_t l = 0, r = c->reflink_gc_nr;
 223
 224                 while (l < r) {
 225                         size_t m = l + (r - l) / 2;
 226                         struct reflink_gc *ref = genradix_ptr(&c->reflink_gc_table, m);
 227                         if (ref->offset <= idx)
 228                                 l = m + 1;
 229                         else
 230                                 r = m;
 231                 }
 232
 233                 while (idx < end && !ret)
 234                         ret = gc_trigger_reflink_p_segment(trans, p, &idx, flags, l++);
 235         }
 236
 237         return ret;
 238 }
 239
 240 int bch2_trigger_reflink_p(struct btree_trans *trans,
 241                            enum btree_id btree_id, unsigned level,
 242                            struct bkey_s_c old,
 243                            struct bkey_s new,
 244                            enum btree_iter_update_trigger_flags flags)
 245 {
 246         if ((flags & BTREE_TRIGGER_transactional) &&
 247             (flags & BTREE_TRIGGER_insert)) {
 248                 struct bch_reflink_p *v = bkey_s_to_reflink_p(new).v;
 249
 250                 v->front_pad = v->back_pad = 0;
 251         }
 252
 253         return trigger_run_overwrite_then_insert(__trigger_reflink_p, trans, btree_id, level, old, new, flags);
 254 }
 255
 256 /* indirect extents */
 257
 258 int bch2_reflink_v_validate(struct bch_fs *c, struct bkey_s_c k,
 259                             enum bch_validate_flags flags)
 260 {
 261         return bch2_bkey_ptrs_validate(c, k, flags);
 262 }
 263
 264 void bch2_reflink_v_to_text(struct printbuf *out, struct bch_fs *c,
 265                             struct bkey_s_c k)
 266 {
 267         struct bkey_s_c_reflink_v r = bkey_s_c_to_reflink_v(k);
 268
 269         prt_printf(out, "refcount: %llu ", le64_to_cpu(r.v->refcount));
 270
 271         bch2_bkey_ptrs_to_text(out, c, k);
 272 }
 273
 274 #if 0
 275 Currently disabled, needs to be debugged:
 276
 277 bool bch2_reflink_v_merge(struct bch_fs *c, struct bkey_s _l, struct bkey_s_c _r)
 278 {
 279         struct bkey_s_reflink_v   l = bkey_s_to_reflink_v(_l);
 280         struct bkey_s_c_reflink_v r = bkey_s_c_to_reflink_v(_r);
 281
 282         return l.v->refcount == r.v->refcount && bch2_extent_merge(c, _l, _r);
 283 }
 284 #endif
 285
 286 static inline void
 287 check_indirect_extent_deleting(struct bkey_s new,
 288                                enum btree_iter_update_trigger_flags *flags)
 289 {
 290         if ((*flags & BTREE_TRIGGER_insert) && !*bkey_refcount(new)) {
 291                 new.k->type = KEY_TYPE_deleted;
 292                 new.k->size = 0;
 293                 set_bkey_val_u64s(new.k, 0);
 294                 *flags &= ~BTREE_TRIGGER_insert;
 295         }
 296 }
 297
 298 int bch2_trigger_reflink_v(struct btree_trans *trans,
 299                            enum btree_id btree_id, unsigned level,
 300                            struct bkey_s_c old, struct bkey_s new,
 301                            enum btree_iter_update_trigger_flags flags)
 302 {
 303         if ((flags & BTREE_TRIGGER_transactional) &&
 304             (flags & BTREE_TRIGGER_insert))
 305                 check_indirect_extent_deleting(new, &flags);
 306
 307         return bch2_trigger_extent(trans, btree_id, level, old, new, flags);
 308 }
 309
 310 /* indirect inline data */
 311
 312 int bch2_indirect_inline_data_validate(struct bch_fs *c, struct bkey_s_c k,
 313                                       enum bch_validate_flags flags)
 314 {
 315         return 0;
 316 }
 317
 318 void bch2_indirect_inline_data_to_text(struct printbuf *out,
 319                                        struct bch_fs *c, struct bkey_s_c k)
 320 {
 321         struct bkey_s_c_indirect_inline_data d = bkey_s_c_to_indirect_inline_data(k);
 322         unsigned datalen = bkey_inline_data_bytes(k.k);
 323
 324         prt_printf(out, "refcount %llu datalen %u: %*phN",
 325                le64_to_cpu(d.v->refcount), datalen,
 326                min(datalen, 32U), d.v->data);
 327 }
 328
 329 int bch2_trigger_indirect_inline_data(struct btree_trans *trans,
 330                               enum btree_id btree_id, unsigned level,
 331                               struct bkey_s_c old, struct bkey_s new,
 332                               enum btree_iter_update_trigger_flags flags)
 333 {
 334         check_indirect_extent_deleting(new, &flags);
 335
 336         return 0;
 337 }
 338
 339 static int bch2_make_extent_indirect(struct btree_trans *trans,
 340                                      struct btree_iter *extent_iter,
 341                                      struct bkey_i *orig)
 342 {
 343         struct bch_fs *c = trans->c;
 344         struct btree_iter reflink_iter = { NULL };
 345         struct bkey_s_c k;
 346         struct bkey_i *r_v;
 347         struct bkey_i_reflink_p *r_p;
 348         __le64 *refcount;
 349         int ret;
 350
 351         if (orig->k.type == KEY_TYPE_inline_data)
 352                 bch2_check_set_feature(c, BCH_FEATURE_reflink_inline_data);
 353
 354         bch2_trans_iter_init(trans, &reflink_iter, BTREE_ID_reflink, POS_MAX,
 355                              BTREE_ITER_intent);
 356         k = bch2_btree_iter_peek_prev(&reflink_iter);
 357         ret = bkey_err(k);
 358         if (ret)
 359                 goto err;
 360
 361         r_v = bch2_trans_kmalloc(trans, sizeof(__le64) + bkey_bytes(&orig->k));
 362         ret = PTR_ERR_OR_ZERO(r_v);
 363         if (ret)
 364                 goto err;
 365
 366         bkey_init(&r_v->k);
 367         r_v->k.type     = bkey_type_to_indirect(&orig->k);
 368         r_v->k.p        = reflink_iter.pos;
 369         bch2_key_resize(&r_v->k, orig->k.size);
 370         r_v->k.bversion = orig->k.bversion;
 371
 372         set_bkey_val_bytes(&r_v->k, sizeof(__le64) + bkey_val_bytes(&orig->k));
 373
 374         refcount        = bkey_refcount(bkey_i_to_s(r_v));
 375         *refcount       = 0;
 376         memcpy(refcount + 1, &orig->v, bkey_val_bytes(&orig->k));
 377
 378         ret = bch2_trans_update(trans, &reflink_iter, r_v, 0);
 379         if (ret)
 380                 goto err;
 381
 382         /*
 383          * orig is in a bkey_buf which statically allocates 5 64s for the val,
 384          * so we know it will be big enough:
 385          */
 386         orig->k.type = KEY_TYPE_reflink_p;
 387         r_p = bkey_i_to_reflink_p(orig);
 388         set_bkey_val_bytes(&r_p->k, sizeof(r_p->v));
 389
 390         /* FORTIFY_SOURCE is broken here, and doesn't provide unsafe_memset() */
 391 #if !defined(__NO_FORTIFY) && defined(__OPTIMIZE__) && defined(CONFIG_FORTIFY_SOURCE)
 392         __underlying_memset(&r_p->v, 0, sizeof(r_p->v));
 393 #else
 394         memset(&r_p->v, 0, sizeof(r_p->v));
 395 #endif
 396
 397         r_p->v.idx = cpu_to_le64(bkey_start_offset(&r_v->k));
 398
 399         ret = bch2_trans_update(trans, extent_iter, &r_p->k_i,
 400                                 BTREE_UPDATE_internal_snapshot_node);
 401 err:
 402         bch2_trans_iter_exit(trans, &reflink_iter);
 403
 404         return ret;
 405 }
 406
 407 static struct bkey_s_c get_next_src(struct btree_iter *iter, struct bpos end)
 408 {
 409         struct bkey_s_c k;
 410         int ret;
 411
 412         for_each_btree_key_upto_continue_norestart(*iter, end, 0, k, ret) {
 413                 if (bkey_extent_is_unwritten(k))
 414                         continue;
 415
 416                 if (bkey_extent_is_data(k.k))
 417                         return k;
 418         }
 419
 420         if (bkey_ge(iter->pos, end))
 421                 bch2_btree_iter_set_pos(iter, end);
 422         return ret ? bkey_s_c_err(ret) : bkey_s_c_null;
 423 }
 424
 425 s64 bch2_remap_range(struct bch_fs *c,
 426                      subvol_inum dst_inum, u64 dst_offset,
 427                      subvol_inum src_inum, u64 src_offset,
 428                      u64 remap_sectors,
 429                      u64 new_i_size, s64 *i_sectors_delta)
 430 {
 431         struct btree_trans *trans;
 432         struct btree_iter dst_iter, src_iter;
 433         struct bkey_s_c src_k;
 434         struct bkey_buf new_dst, new_src;
 435         struct bpos dst_start = POS(dst_inum.inum, dst_offset);
 436         struct bpos src_start = POS(src_inum.inum, src_offset);
 437         struct bpos dst_end = dst_start, src_end = src_start;
 438         struct bch_io_opts opts;
 439         struct bpos src_want;
 440         u64 dst_done = 0;
 441         u32 dst_snapshot, src_snapshot;
 442         int ret = 0, ret2 = 0;
 443
 444         if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_reflink))
 445                 return -BCH_ERR_erofs_no_writes;
 446
 447         bch2_check_set_feature(c, BCH_FEATURE_reflink);
 448
 449         dst_end.offset += remap_sectors;
 450         src_end.offset += remap_sectors;
 451
 452         bch2_bkey_buf_init(&new_dst);
 453         bch2_bkey_buf_init(&new_src);
 454         trans = bch2_trans_get(c);
 455
 456         ret = bch2_inum_opts_get(trans, src_inum, &opts);
 457         if (ret)
 458                 goto err;
 459
 460         bch2_trans_iter_init(trans, &src_iter, BTREE_ID_extents, src_start,
 461                              BTREE_ITER_intent);
 462         bch2_trans_iter_init(trans, &dst_iter, BTREE_ID_extents, dst_start,
 463                              BTREE_ITER_intent);
 464
 465         while ((ret == 0 ||
 466                 bch2_err_matches(ret, BCH_ERR_transaction_restart)) &&
 467                bkey_lt(dst_iter.pos, dst_end)) {
 468                 struct disk_reservation disk_res = { 0 };
 469
 470                 bch2_trans_begin(trans);
 471
 472                 if (fatal_signal_pending(current)) {
 473                         ret = -EINTR;
 474                         break;
 475                 }
 476
 477                 ret = bch2_subvolume_get_snapshot(trans, src_inum.subvol,
 478                                                   &src_snapshot);
 479                 if (ret)
 480                         continue;
 481
 482                 bch2_btree_iter_set_snapshot(&src_iter, src_snapshot);
 483
 484                 ret = bch2_subvolume_get_snapshot(trans, dst_inum.subvol,
 485                                                   &dst_snapshot);
 486                 if (ret)
 487                         continue;
 488
 489                 bch2_btree_iter_set_snapshot(&dst_iter, dst_snapshot);
 490
 491                 if (dst_inum.inum < src_inum.inum) {
 492                         /* Avoid some lock cycle transaction restarts */
 493                         ret = bch2_btree_iter_traverse(&dst_iter);
 494                         if (ret)
 495                                 continue;
 496                 }
 497
 498                 dst_done = dst_iter.pos.offset - dst_start.offset;
 499                 src_want = POS(src_start.inode, src_start.offset + dst_done);
 500                 bch2_btree_iter_set_pos(&src_iter, src_want);
 501
 502                 src_k = get_next_src(&src_iter, src_end);
 503                 ret = bkey_err(src_k);
 504                 if (ret)
 505                         continue;
 506
 507                 if (bkey_lt(src_want, src_iter.pos)) {
 508                         ret = bch2_fpunch_at(trans, &dst_iter, dst_inum,
 509                                         min(dst_end.offset,
 510                                             dst_iter.pos.offset +
 511                                             src_iter.pos.offset - src_want.offset),
 512                                         i_sectors_delta);
 513                         continue;
 514                 }
 515
 516                 if (src_k.k->type != KEY_TYPE_reflink_p) {
 517                         bch2_btree_iter_set_pos_to_extent_start(&src_iter);
 518
 519                         bch2_bkey_buf_reassemble(&new_src, c, src_k);
 520                         src_k = bkey_i_to_s_c(new_src.k);
 521
 522                         ret = bch2_make_extent_indirect(trans, &src_iter,
 523                                                 new_src.k);
 524                         if (ret)
 525                                 continue;
 526
 527                         BUG_ON(src_k.k->type != KEY_TYPE_reflink_p);
 528                 }
 529
 530                 if (src_k.k->type == KEY_TYPE_reflink_p) {
 531                         struct bkey_s_c_reflink_p src_p =
 532                                 bkey_s_c_to_reflink_p(src_k);
 533                         struct bkey_i_reflink_p *dst_p =
 534                                 bkey_reflink_p_init(new_dst.k);
 535
 536                         u64 offset = le64_to_cpu(src_p.v->idx) +
 537                                 (src_want.offset -
 538                                  bkey_start_offset(src_k.k));
 539
 540                         dst_p->v.idx = cpu_to_le64(offset);
 541                 } else {
 542                         BUG();
 543                 }
 544
 545                 new_dst.k->k.p = dst_iter.pos;
 546                 bch2_key_resize(&new_dst.k->k,
 547                                 min(src_k.k->p.offset - src_want.offset,
 548                                     dst_end.offset - dst_iter.pos.offset));
 549
 550                 ret =   bch2_bkey_set_needs_rebalance(c, new_dst.k, &opts) ?:
 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 }