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

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include "bcachefs.h"
   3 #include "bbpos.h"
   4 #include "alloc_background.h"
   5 #include "backpointers.h"
   6 #include "btree_cache.h"
   7 #include "btree_update.h"
   8 #include "btree_write_buffer.h"
   9 #include "error.h"
  10
  11 #include <linux/mm.h>
  12
  13 static bool extent_matches_bp(struct bch_fs *c,
  14                               enum btree_id btree_id, unsigned level,
  15                               struct bkey_s_c k,
  16                               struct bpos bucket,
  17                               struct bch_backpointer bp)
  18 {
  19         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
  20         const union bch_extent_entry *entry;
  21         struct extent_ptr_decoded p;
  22
  23         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
  24                 struct bpos bucket2;
  25                 struct bch_backpointer bp2;
  26
  27                 if (p.ptr.cached)
  28                         continue;
  29
  30                 bch2_extent_ptr_to_bp(c, btree_id, level, k, p,
  31                                       &bucket2, &bp2);
  32                 if (bpos_eq(bucket, bucket2) &&
  33                     !memcmp(&bp, &bp2, sizeof(bp)))
  34                         return true;
  35         }
  36
  37         return false;
  38 }
  39
  40 int bch2_backpointer_invalid(const struct bch_fs *c, struct bkey_s_c k,
  41                              unsigned flags, struct printbuf *err)
  42 {
  43         struct bkey_s_c_backpointer bp = bkey_s_c_to_backpointer(k);
  44         struct bpos bucket = bp_pos_to_bucket(c, bp.k->p);
  45
  46         if (!bpos_eq(bp.k->p, bucket_pos_to_bp(c, bucket, bp.v->bucket_offset))) {
  47                 prt_str(err, "backpointer at wrong pos");
  48                 return -BCH_ERR_invalid_bkey;
  49         }
  50
  51         return 0;
  52 }
  53
  54 void bch2_backpointer_to_text(struct printbuf *out, const struct bch_backpointer *bp)
  55 {
  56         prt_printf(out, "btree=%s l=%u offset=%llu:%u len=%u pos=",
  57                bch2_btree_ids[bp->btree_id],
  58                bp->level,
  59                (u64) (bp->bucket_offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT),
  60                (u32) bp->bucket_offset & ~(~0U << MAX_EXTENT_COMPRESS_RATIO_SHIFT),
  61                bp->bucket_len);
  62         bch2_bpos_to_text(out, bp->pos);
  63 }
  64
  65 void bch2_backpointer_k_to_text(struct printbuf *out, struct bch_fs *c, struct bkey_s_c k)
  66 {
  67         prt_str(out, "bucket=");
  68         bch2_bpos_to_text(out, bp_pos_to_bucket(c, k.k->p));
  69         prt_str(out, " ");
  70
  71         bch2_backpointer_to_text(out, bkey_s_c_to_backpointer(k).v);
  72 }
  73
  74 void bch2_backpointer_swab(struct bkey_s k)
  75 {
  76         struct bkey_s_backpointer bp = bkey_s_to_backpointer(k);
  77
  78         bp.v->bucket_offset     = swab32(bp.v->bucket_offset);
  79         bp.v->bucket_len        = swab32(bp.v->bucket_len);
  80         bch2_bpos_swab(&bp.v->pos);
  81 }
  82
  83 static noinline int backpointer_mod_err(struct btree_trans *trans,
  84                                         struct bch_backpointer bp,
  85                                         struct bkey_s_c bp_k,
  86                                         struct bkey_s_c orig_k,
  87                                         bool insert)
  88 {
  89         struct bch_fs *c = trans->c;
  90         struct printbuf buf = PRINTBUF;
  91
  92         if (insert) {
  93                 prt_printf(&buf, "existing backpointer found when inserting ");
  94                 bch2_backpointer_to_text(&buf, &bp);
  95                 prt_newline(&buf);
  96                 printbuf_indent_add(&buf, 2);
  97
  98                 prt_printf(&buf, "found ");
  99                 bch2_bkey_val_to_text(&buf, c, bp_k);
 100                 prt_newline(&buf);
 101
 102                 prt_printf(&buf, "for ");
 103                 bch2_bkey_val_to_text(&buf, c, orig_k);
 104
 105                 bch_err(c, "%s", buf.buf);
 106         } else if (test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags)) {
 107                 prt_printf(&buf, "backpointer not found when deleting");
 108                 prt_newline(&buf);
 109                 printbuf_indent_add(&buf, 2);
 110
 111                 prt_printf(&buf, "searching for ");
 112                 bch2_backpointer_to_text(&buf, &bp);
 113                 prt_newline(&buf);
 114
 115                 prt_printf(&buf, "got ");
 116                 bch2_bkey_val_to_text(&buf, c, bp_k);
 117                 prt_newline(&buf);
 118
 119                 prt_printf(&buf, "for ");
 120                 bch2_bkey_val_to_text(&buf, c, orig_k);
 121
 122                 bch_err(c, "%s", buf.buf);
 123         }
 124
 125         printbuf_exit(&buf);
 126
 127         if (test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags)) {
 128                 bch2_inconsistent_error(c);
 129                 return -EIO;
 130         } else {
 131                 return 0;
 132         }
 133 }
 134
 135 int bch2_bucket_backpointer_mod_nowritebuffer(struct btree_trans *trans,
 136                                 struct bpos bucket,
 137                                 struct bch_backpointer bp,
 138                                 struct bkey_s_c orig_k,
 139                                 bool insert)
 140 {
 141         struct bch_fs *c = trans->c;
 142         struct bkey_i_backpointer *bp_k;
 143         struct btree_iter bp_iter;
 144         struct bkey_s_c k;
 145         int ret;
 146
 147         bp_k = bch2_trans_kmalloc_nomemzero(trans, sizeof(struct bkey_i_backpointer));
 148         ret = PTR_ERR_OR_ZERO(bp_k);
 149         if (ret)
 150                 return ret;
 151
 152         bkey_backpointer_init(&bp_k->k_i);
 153         bp_k->k.p = bucket_pos_to_bp(c, bucket, bp.bucket_offset);
 154         bp_k->v = bp;
 155
 156         if (!insert) {
 157                 bp_k->k.type = KEY_TYPE_deleted;
 158                 set_bkey_val_u64s(&bp_k->k, 0);
 159         }
 160
 161         k = bch2_bkey_get_iter(trans, &bp_iter, BTREE_ID_backpointers,
 162                                bp_k->k.p,
 163                                BTREE_ITER_INTENT|
 164                                BTREE_ITER_SLOTS|
 165                                BTREE_ITER_WITH_UPDATES);
 166         ret = bkey_err(k);
 167         if (ret)
 168                 goto err;
 169
 170         if (insert
 171             ? k.k->type
 172             : (k.k->type != KEY_TYPE_backpointer ||
 173                memcmp(bkey_s_c_to_backpointer(k).v, &bp, sizeof(bp)))) {
 174                 ret = backpointer_mod_err(trans, bp, k, orig_k, insert);
 175                 if (ret)
 176                         goto err;
 177         }
 178
 179         ret = bch2_trans_update(trans, &bp_iter, &bp_k->k_i, 0);
 180 err:
 181         bch2_trans_iter_exit(trans, &bp_iter);
 182         return ret;
 183 }
 184
 185 /*
 186  * Find the next backpointer >= *bp_offset:
 187  */
 188 int bch2_get_next_backpointer(struct btree_trans *trans,
 189                               struct bpos bucket, int gen,
 190                               struct bpos *bp_pos,
 191                               struct bch_backpointer *bp,
 192                               unsigned iter_flags)
 193 {
 194         struct bch_fs *c = trans->c;
 195         struct bpos bp_end_pos = bucket_pos_to_bp(c, bpos_nosnap_successor(bucket), 0);
 196         struct btree_iter alloc_iter = { NULL }, bp_iter = { NULL };
 197         struct bkey_s_c k;
 198         int ret = 0;
 199
 200         if (bpos_ge(*bp_pos, bp_end_pos))
 201                 goto done;
 202
 203         if (gen >= 0) {
 204                 k = bch2_bkey_get_iter(trans, &alloc_iter, BTREE_ID_alloc,
 205                                        bucket, BTREE_ITER_CACHED|iter_flags);
 206                 ret = bkey_err(k);
 207                 if (ret)
 208                         goto out;
 209
 210                 if (k.k->type != KEY_TYPE_alloc_v4 ||
 211                     bkey_s_c_to_alloc_v4(k).v->gen != gen)
 212                         goto done;
 213         }
 214
 215         *bp_pos = bpos_max(*bp_pos, bucket_pos_to_bp(c, bucket, 0));
 216
 217         for_each_btree_key_norestart(trans, bp_iter, BTREE_ID_backpointers,
 218                                      *bp_pos, iter_flags, k, ret) {
 219                 if (bpos_ge(k.k->p, bp_end_pos))
 220                         break;
 221
 222                 *bp_pos = k.k->p;
 223                 *bp = *bkey_s_c_to_backpointer(k).v;
 224                 goto out;
 225         }
 226 done:
 227         *bp_pos = SPOS_MAX;
 228 out:
 229         bch2_trans_iter_exit(trans, &bp_iter);
 230         bch2_trans_iter_exit(trans, &alloc_iter);
 231         return ret;
 232 }
 233
 234 static void backpointer_not_found(struct btree_trans *trans,
 235                                   struct bpos bp_pos,
 236                                   struct bch_backpointer bp,
 237                                   struct bkey_s_c k,
 238                                   const char *thing_it_points_to)
 239 {
 240         struct bch_fs *c = trans->c;
 241         struct printbuf buf = PRINTBUF;
 242         struct bpos bucket = bp_pos_to_bucket(c, bp_pos);
 243
 244         if (likely(!bch2_backpointers_no_use_write_buffer))
 245                 return;
 246
 247         prt_printf(&buf, "backpointer doesn't match %s it points to:\n  ",
 248                    thing_it_points_to);
 249         prt_printf(&buf, "bucket: ");
 250         bch2_bpos_to_text(&buf, bucket);
 251         prt_printf(&buf, "\n  ");
 252
 253         prt_printf(&buf, "backpointer pos: ");
 254         bch2_bpos_to_text(&buf, bp_pos);
 255         prt_printf(&buf, "\n  ");
 256
 257         bch2_backpointer_to_text(&buf, &bp);
 258         prt_printf(&buf, "\n  ");
 259         bch2_bkey_val_to_text(&buf, c, k);
 260         if (!test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags))
 261                 bch_err_ratelimited(c, "%s", buf.buf);
 262         else
 263                 bch2_trans_inconsistent(trans, "%s", buf.buf);
 264
 265         printbuf_exit(&buf);
 266 }
 267
 268 struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *trans,
 269                                          struct btree_iter *iter,
 270                                          struct bpos bp_pos,
 271                                          struct bch_backpointer bp,
 272                                          unsigned iter_flags)
 273 {
 274         struct bch_fs *c = trans->c;
 275         struct bpos bucket = bp_pos_to_bucket(c, bp_pos);
 276         struct bkey_s_c k;
 277
 278         bch2_trans_node_iter_init(trans, iter,
 279                                   bp.btree_id,
 280                                   bp.pos,
 281                                   0,
 282                                   min(bp.level, c->btree_roots[bp.btree_id].level),
 283                                   iter_flags);
 284         k = bch2_btree_iter_peek_slot(iter);
 285         if (bkey_err(k)) {
 286                 bch2_trans_iter_exit(trans, iter);
 287                 return k;
 288         }
 289
 290         if (bp.level == c->btree_roots[bp.btree_id].level + 1)
 291                 k = bkey_i_to_s_c(&c->btree_roots[bp.btree_id].key);
 292
 293         if (k.k && extent_matches_bp(c, bp.btree_id, bp.level, k, bucket, bp))
 294                 return k;
 295
 296         bch2_trans_iter_exit(trans, iter);
 297
 298         if (unlikely(bch2_backpointers_no_use_write_buffer)) {
 299                 if (bp.level) {
 300                         struct btree *b;
 301
 302                         /*
 303                          * If a backpointer for a btree node wasn't found, it may be
 304                          * because it was overwritten by a new btree node that hasn't
 305                          * been written out yet - backpointer_get_node() checks for
 306                          * this:
 307                          */
 308                         b = bch2_backpointer_get_node(trans, iter, bp_pos, bp);
 309                         if (!IS_ERR_OR_NULL(b))
 310                                 return bkey_i_to_s_c(&b->key);
 311
 312                         bch2_trans_iter_exit(trans, iter);
 313
 314                         if (IS_ERR(b))
 315                                 return bkey_s_c_err(PTR_ERR(b));
 316                         return bkey_s_c_null;
 317                 }
 318
 319                 backpointer_not_found(trans, bp_pos, bp, k, "extent");
 320         }
 321
 322         return bkey_s_c_null;
 323 }
 324
 325 struct btree *bch2_backpointer_get_node(struct btree_trans *trans,
 326                                         struct btree_iter *iter,
 327                                         struct bpos bp_pos,
 328                                         struct bch_backpointer bp)
 329 {
 330         struct bch_fs *c = trans->c;
 331         struct bpos bucket = bp_pos_to_bucket(c, bp_pos);
 332         struct btree *b;
 333
 334         BUG_ON(!bp.level);
 335
 336         bch2_trans_node_iter_init(trans, iter,
 337                                   bp.btree_id,
 338                                   bp.pos,
 339                                   0,
 340                                   bp.level - 1,
 341                                   0);
 342         b = bch2_btree_iter_peek_node(iter);
 343         if (IS_ERR(b))
 344                 goto err;
 345
 346         if (b && extent_matches_bp(c, bp.btree_id, bp.level,
 347                                    bkey_i_to_s_c(&b->key),
 348                                    bucket, bp))
 349                 return b;
 350
 351         if (b && btree_node_will_make_reachable(b)) {
 352                 b = ERR_PTR(-BCH_ERR_backpointer_to_overwritten_btree_node);
 353         } else {
 354                 backpointer_not_found(trans, bp_pos, bp,
 355                                       bkey_i_to_s_c(&b->key), "btree node");
 356                 b = NULL;
 357         }
 358 err:
 359         bch2_trans_iter_exit(trans, iter);
 360         return b;
 361 }
 362
 363 static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_iter *bp_iter,
 364                                         struct bkey_s_c k)
 365 {
 366         struct bch_fs *c = trans->c;
 367         struct btree_iter alloc_iter = { NULL };
 368         struct bch_dev *ca;
 369         struct bkey_s_c alloc_k;
 370         struct printbuf buf = PRINTBUF;
 371         int ret = 0;
 372
 373         if (fsck_err_on(!bch2_dev_exists2(c, k.k->p.inode), c,
 374                         "backpointer for mising device:\n%s",
 375                         (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
 376                 ret = bch2_btree_delete_at(trans, bp_iter, 0);
 377                 goto out;
 378         }
 379
 380         ca = bch_dev_bkey_exists(c, k.k->p.inode);
 381
 382         alloc_k = bch2_bkey_get_iter(trans, &alloc_iter, BTREE_ID_alloc,
 383                                      bp_pos_to_bucket(c, k.k->p), 0);
 384         ret = bkey_err(alloc_k);
 385         if (ret)
 386                 goto out;
 387
 388         if (fsck_err_on(alloc_k.k->type != KEY_TYPE_alloc_v4, c,
 389                         "backpointer for nonexistent alloc key: %llu:%llu:0\n%s",
 390                         alloc_iter.pos.inode, alloc_iter.pos.offset,
 391                         (bch2_bkey_val_to_text(&buf, c, alloc_k), buf.buf))) {
 392                 ret = bch2_btree_delete_at(trans, bp_iter, 0);
 393                 goto out;
 394         }
 395 out:
 396 fsck_err:
 397         bch2_trans_iter_exit(trans, &alloc_iter);
 398         printbuf_exit(&buf);
 399         return ret;
 400 }
 401
 402 /* verify that every backpointer has a corresponding alloc key */
 403 int bch2_check_btree_backpointers(struct bch_fs *c)
 404 {
 405         struct btree_iter iter;
 406         struct bkey_s_c k;
 407
 408         return bch2_trans_run(c,
 409                 for_each_btree_key_commit(&trans, iter,
 410                         BTREE_ID_backpointers, POS_MIN, 0, k,
 411                         NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
 412                   bch2_check_btree_backpointer(&trans, &iter, k)));
 413 }
 414
 415 struct bpos_level {
 416         unsigned        level;
 417         struct bpos     pos;
 418 };
 419
 420 static int check_bp_exists(struct btree_trans *trans,
 421                            struct bpos bucket,
 422                            struct bch_backpointer bp,
 423                            struct bkey_s_c orig_k,
 424                            struct bpos bucket_start,
 425                            struct bpos bucket_end,
 426                            struct bpos_level *last_flushed)
 427 {
 428         struct bch_fs *c = trans->c;
 429         struct btree_iter bp_iter = { NULL };
 430         struct printbuf buf = PRINTBUF;
 431         struct bkey_s_c bp_k;
 432         int ret;
 433
 434         if (bpos_lt(bucket, bucket_start) ||
 435             bpos_gt(bucket, bucket_end))
 436                 return 0;
 437
 438         if (!bch2_dev_bucket_exists(c, bucket))
 439                 goto missing;
 440
 441         bp_k = bch2_bkey_get_iter(trans, &bp_iter, BTREE_ID_backpointers,
 442                                   bucket_pos_to_bp(c, bucket, bp.bucket_offset),
 443                                   0);
 444         ret = bkey_err(bp_k);
 445         if (ret)
 446                 goto err;
 447
 448         if (bp_k.k->type != KEY_TYPE_backpointer ||
 449             memcmp(bkey_s_c_to_backpointer(bp_k).v, &bp, sizeof(bp))) {
 450                 if (last_flushed->level != bp.level ||
 451                     !bpos_eq(last_flushed->pos, orig_k.k->p)) {
 452                         last_flushed->level = bp.level;
 453                         last_flushed->pos = orig_k.k->p;
 454
 455                         ret = bch2_btree_write_buffer_flush_sync(trans) ?:
 456                                 -BCH_ERR_transaction_restart_write_buffer_flush;
 457                         goto out;
 458                 }
 459                 goto missing;
 460         }
 461 out:
 462 err:
 463 fsck_err:
 464         bch2_trans_iter_exit(trans, &bp_iter);
 465         printbuf_exit(&buf);
 466         return ret;
 467 missing:
 468         prt_printf(&buf, "missing backpointer for btree=%s l=%u ",
 469                bch2_btree_ids[bp.btree_id], bp.level);
 470         bch2_bkey_val_to_text(&buf, c, orig_k);
 471         prt_printf(&buf, "\nbp pos ");
 472         bch2_bpos_to_text(&buf, bp_iter.pos);
 473
 474         if (c->sb.version < bcachefs_metadata_version_backpointers ||
 475             c->opts.reconstruct_alloc ||
 476             fsck_err(c, "%s", buf.buf))
 477                 ret = bch2_bucket_backpointer_mod(trans, bucket, bp, orig_k, true);
 478
 479         goto out;
 480 }
 481
 482 static int check_extent_to_backpointers(struct btree_trans *trans,
 483                                         struct btree_iter *iter,
 484                                         struct bpos bucket_start,
 485                                         struct bpos bucket_end,
 486                                         struct bpos_level *last_flushed)
 487 {
 488         struct bch_fs *c = trans->c;
 489         struct bkey_ptrs_c ptrs;
 490         const union bch_extent_entry *entry;
 491         struct extent_ptr_decoded p;
 492         struct bkey_s_c k;
 493         int ret;
 494
 495         k = bch2_btree_iter_peek_all_levels(iter);
 496         ret = bkey_err(k);
 497         if (ret)
 498                 return ret;
 499         if (!k.k)
 500                 return 0;
 501
 502         ptrs = bch2_bkey_ptrs_c(k);
 503         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 504                 struct bpos bucket_pos;
 505                 struct bch_backpointer bp;
 506
 507                 if (p.ptr.cached)
 508                         continue;
 509
 510                 bch2_extent_ptr_to_bp(c, iter->btree_id, iter->path->level,
 511                                       k, p, &bucket_pos, &bp);
 512
 513                 ret = check_bp_exists(trans, bucket_pos, bp, k,
 514                                       bucket_start, bucket_end,
 515                                       last_flushed);
 516                 if (ret)
 517                         return ret;
 518         }
 519
 520         return 0;
 521 }
 522
 523 static int check_btree_root_to_backpointers(struct btree_trans *trans,
 524                                             enum btree_id btree_id,
 525                                             struct bpos bucket_start,
 526                                             struct bpos bucket_end,
 527                                             struct bpos_level *last_flushed)
 528 {
 529         struct bch_fs *c = trans->c;
 530         struct btree_iter iter;
 531         struct btree *b;
 532         struct bkey_s_c k;
 533         struct bkey_ptrs_c ptrs;
 534         struct extent_ptr_decoded p;
 535         const union bch_extent_entry *entry;
 536         int ret;
 537
 538         bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN, 0,
 539                                   c->btree_roots[btree_id].level, 0);
 540         b = bch2_btree_iter_peek_node(&iter);
 541         ret = PTR_ERR_OR_ZERO(b);
 542         if (ret)
 543                 goto err;
 544
 545         BUG_ON(b != btree_node_root(c, b));
 546
 547         k = bkey_i_to_s_c(&b->key);
 548         ptrs = bch2_bkey_ptrs_c(k);
 549         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 550                 struct bpos bucket_pos;
 551                 struct bch_backpointer bp;
 552
 553                 if (p.ptr.cached)
 554                         continue;
 555
 556                 bch2_extent_ptr_to_bp(c, iter.btree_id, b->c.level + 1,
 557                                       k, p, &bucket_pos, &bp);
 558
 559                 ret = check_bp_exists(trans, bucket_pos, bp, k,
 560                                       bucket_start, bucket_end,
 561                                       last_flushed);
 562                 if (ret)
 563                         goto err;
 564         }
 565 err:
 566         bch2_trans_iter_exit(trans, &iter);
 567         return ret;
 568 }
 569
 570 static inline struct bbpos bp_to_bbpos(struct bch_backpointer bp)
 571 {
 572         return (struct bbpos) {
 573                 .btree  = bp.btree_id,
 574                 .pos    = bp.pos,
 575         };
 576 }
 577
 578 static size_t btree_nodes_fit_in_ram(struct bch_fs *c)
 579 {
 580         struct sysinfo i;
 581         u64 mem_bytes;
 582
 583         si_meminfo(&i);
 584         mem_bytes = i.totalram * i.mem_unit;
 585         return div_u64(mem_bytes >> 1, btree_bytes(c));
 586 }
 587
 588 int bch2_get_btree_in_memory_pos(struct btree_trans *trans,
 589                                  unsigned btree_leaf_mask,
 590                                  unsigned btree_interior_mask,
 591                                  struct bbpos start, struct bbpos *end)
 592 {
 593         struct btree_iter iter;
 594         struct bkey_s_c k;
 595         size_t btree_nodes = btree_nodes_fit_in_ram(trans->c);
 596         enum btree_id btree;
 597         int ret = 0;
 598
 599         for (btree = start.btree; btree < BTREE_ID_NR && !ret; btree++) {
 600                 unsigned depth = ((1U << btree) & btree_leaf_mask) ? 1 : 2;
 601
 602                 if (!((1U << btree) & btree_leaf_mask) &&
 603                     !((1U << btree) & btree_interior_mask))
 604                         continue;
 605
 606                 bch2_trans_node_iter_init(trans, &iter, btree,
 607                                           btree == start.btree ? start.pos : POS_MIN,
 608                                           0, depth, 0);
 609                 /*
 610                  * for_each_btree_key_contineu() doesn't check the return value
 611                  * from bch2_btree_iter_advance(), which is needed when
 612                  * iterating over interior nodes where we'll see keys at
 613                  * SPOS_MAX:
 614                  */
 615                 do {
 616                         k = __bch2_btree_iter_peek_and_restart(trans, &iter, 0);
 617                         ret = bkey_err(k);
 618                         if (!k.k || ret)
 619                                 break;
 620
 621                         --btree_nodes;
 622                         if (!btree_nodes) {
 623                                 *end = BBPOS(btree, k.k->p);
 624                                 bch2_trans_iter_exit(trans, &iter);
 625                                 return 0;
 626                         }
 627                 } while (bch2_btree_iter_advance(&iter));
 628                 bch2_trans_iter_exit(trans, &iter);
 629         }
 630
 631         *end = BBPOS_MAX;
 632         return ret;
 633 }
 634
 635 static int bch2_check_extents_to_backpointers_pass(struct btree_trans *trans,
 636                                                    struct bpos bucket_start,
 637                                                    struct bpos bucket_end)
 638 {
 639         struct btree_iter iter;
 640         enum btree_id btree_id;
 641         struct bpos_level last_flushed = { UINT_MAX };
 642         int ret = 0;
 643
 644         for (btree_id = 0; btree_id < BTREE_ID_NR; btree_id++) {
 645                 unsigned depth = btree_type_has_ptrs(btree_id) ? 0 : 1;
 646
 647                 bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN, 0,
 648                                           depth,
 649                                           BTREE_ITER_ALL_LEVELS|
 650                                           BTREE_ITER_PREFETCH);
 651
 652                 do {
 653                         ret = commit_do(trans, NULL, NULL,
 654                                         BTREE_INSERT_LAZY_RW|
 655                                         BTREE_INSERT_NOFAIL,
 656                                         check_extent_to_backpointers(trans, &iter,
 657                                                                 bucket_start, bucket_end,
 658                                                                 &last_flushed));
 659                         if (ret)
 660                                 break;
 661                 } while (!bch2_btree_iter_advance(&iter));
 662
 663                 bch2_trans_iter_exit(trans, &iter);
 664
 665                 if (ret)
 666                         break;
 667
 668                 ret = commit_do(trans, NULL, NULL,
 669                                 BTREE_INSERT_LAZY_RW|
 670                                 BTREE_INSERT_NOFAIL,
 671                                 check_btree_root_to_backpointers(trans, btree_id,
 672                                                         bucket_start, bucket_end,
 673                                                         &last_flushed));
 674                 if (ret)
 675                         break;
 676         }
 677         return ret;
 678 }
 679
 680 static struct bpos bucket_pos_to_bp_safe(const struct bch_fs *c,
 681                                          struct bpos bucket)
 682 {
 683         return bch2_dev_exists2(c, bucket.inode)
 684                 ? bucket_pos_to_bp(c, bucket, 0)
 685                 : bucket;
 686 }
 687
 688 int bch2_get_alloc_in_memory_pos(struct btree_trans *trans,
 689                                  struct bpos start, struct bpos *end)
 690 {
 691         struct btree_iter alloc_iter;
 692         struct btree_iter bp_iter;
 693         struct bkey_s_c alloc_k, bp_k;
 694         size_t btree_nodes = btree_nodes_fit_in_ram(trans->c);
 695         bool alloc_end = false, bp_end = false;
 696         int ret = 0;
 697
 698         bch2_trans_node_iter_init(trans, &alloc_iter, BTREE_ID_alloc,
 699                                   start, 0, 1, 0);
 700         bch2_trans_node_iter_init(trans, &bp_iter, BTREE_ID_backpointers,
 701                                   bucket_pos_to_bp_safe(trans->c, start), 0, 1, 0);
 702         while (1) {
 703                 alloc_k = !alloc_end
 704                         ? __bch2_btree_iter_peek_and_restart(trans, &alloc_iter, 0)
 705                         : bkey_s_c_null;
 706                 bp_k = !bp_end
 707                         ? __bch2_btree_iter_peek_and_restart(trans, &bp_iter, 0)
 708                         : bkey_s_c_null;
 709
 710                 ret = bkey_err(alloc_k) ?: bkey_err(bp_k);
 711                 if ((!alloc_k.k && !bp_k.k) || ret) {
 712                         *end = SPOS_MAX;
 713                         break;
 714                 }
 715
 716                 --btree_nodes;
 717                 if (!btree_nodes) {
 718                         *end = alloc_k.k->p;
 719                         break;
 720                 }
 721
 722                 if (bpos_lt(alloc_iter.pos, SPOS_MAX) &&
 723                     bpos_lt(bucket_pos_to_bp_safe(trans->c, alloc_iter.pos), bp_iter.pos)) {
 724                         if (!bch2_btree_iter_advance(&alloc_iter))
 725                                 alloc_end = true;
 726                 } else {
 727                         if (!bch2_btree_iter_advance(&bp_iter))
 728                                 bp_end = true;
 729                 }
 730         }
 731         bch2_trans_iter_exit(trans, &bp_iter);
 732         bch2_trans_iter_exit(trans, &alloc_iter);
 733         return ret;
 734 }
 735
 736 int bch2_check_extents_to_backpointers(struct bch_fs *c)
 737 {
 738         struct btree_trans trans;
 739         struct bpos start = POS_MIN, end;
 740         int ret;
 741
 742         bch2_trans_init(&trans, c, 0, 0);
 743         while (1) {
 744                 ret = bch2_get_alloc_in_memory_pos(&trans, start, &end);
 745                 if (ret)
 746                         break;
 747
 748                 if (bpos_eq(start, POS_MIN) && !bpos_eq(end, SPOS_MAX))
 749                         bch_verbose(c, "%s(): alloc info does not fit in ram, running in multiple passes with %zu nodes per pass",
 750                                     __func__, btree_nodes_fit_in_ram(c));
 751
 752                 if (!bpos_eq(start, POS_MIN) || !bpos_eq(end, SPOS_MAX)) {
 753                         struct printbuf buf = PRINTBUF;
 754
 755                         prt_str(&buf, "check_extents_to_backpointers(): ");
 756                         bch2_bpos_to_text(&buf, start);
 757                         prt_str(&buf, "-");
 758                         bch2_bpos_to_text(&buf, end);
 759
 760                         bch_verbose(c, "%s", buf.buf);
 761                         printbuf_exit(&buf);
 762                 }
 763
 764                 ret = bch2_check_extents_to_backpointers_pass(&trans, start, end);
 765                 if (ret || bpos_eq(end, SPOS_MAX))
 766                         break;
 767
 768                 start = bpos_successor(end);
 769         }
 770         bch2_trans_exit(&trans);
 771
 772         return ret;
 773 }
 774
 775 static int check_one_backpointer(struct btree_trans *trans,
 776                                  struct bbpos start,
 777                                  struct bbpos end,
 778                                  struct bkey_s_c_backpointer bp,
 779                                  struct bpos *last_flushed_pos)
 780 {
 781         struct bch_fs *c = trans->c;
 782         struct btree_iter iter;
 783         struct bbpos pos = bp_to_bbpos(*bp.v);
 784         struct bkey_s_c k;
 785         struct printbuf buf = PRINTBUF;
 786         int ret;
 787
 788         if (bbpos_cmp(pos, start) < 0 ||
 789             bbpos_cmp(pos, end) > 0)
 790                 return 0;
 791
 792         k = bch2_backpointer_get_key(trans, &iter, bp.k->p, *bp.v, 0);
 793         ret = bkey_err(k);
 794         if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node)
 795                 return 0;
 796         if (ret)
 797                 return ret;
 798
 799         if (!k.k && !bpos_eq(*last_flushed_pos, bp.k->p)) {
 800                 *last_flushed_pos = bp.k->p;
 801                 ret = bch2_btree_write_buffer_flush_sync(trans) ?:
 802                         -BCH_ERR_transaction_restart_write_buffer_flush;
 803                 goto out;
 804         }
 805
 806         if (fsck_err_on(!k.k, c,
 807                         "backpointer for missing extent\n  %s",
 808                         (bch2_backpointer_k_to_text(&buf, c, bp.s_c), buf.buf)))
 809                 return bch2_btree_delete_at_buffered(trans, BTREE_ID_backpointers, bp.k->p);
 810 out:
 811 fsck_err:
 812         bch2_trans_iter_exit(trans, &iter);
 813         printbuf_exit(&buf);
 814         return ret;
 815 }
 816
 817 static int bch2_check_backpointers_to_extents_pass(struct btree_trans *trans,
 818                                                    struct bbpos start,
 819                                                    struct bbpos end)
 820 {
 821         struct btree_iter iter;
 822         struct bkey_s_c k;
 823         struct bpos last_flushed_pos = SPOS_MAX;
 824
 825         return for_each_btree_key_commit(trans, iter, BTREE_ID_backpointers,
 826                                   POS_MIN, BTREE_ITER_PREFETCH, k,
 827                                   NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
 828                 check_one_backpointer(trans, start, end,
 829                                       bkey_s_c_to_backpointer(k),
 830                                       &last_flushed_pos));
 831 }
 832
 833 int bch2_check_backpointers_to_extents(struct bch_fs *c)
 834 {
 835         struct btree_trans trans;
 836         struct bbpos start = (struct bbpos) { .btree = 0, .pos = POS_MIN, }, end;
 837         int ret;
 838
 839         bch2_trans_init(&trans, c, 0, 0);
 840         while (1) {
 841                 ret = bch2_get_btree_in_memory_pos(&trans,
 842                                                    (1U << BTREE_ID_extents)|
 843                                                    (1U << BTREE_ID_reflink),
 844                                                    ~0,
 845                                                    start, &end);
 846                 if (ret)
 847                         break;
 848
 849                 if (!bbpos_cmp(start, BBPOS_MIN) &&
 850                     bbpos_cmp(end, BBPOS_MAX))
 851                         bch_verbose(c, "%s(): extents do not fit in ram, running in multiple passes with %zu nodes per pass",
 852                                     __func__, btree_nodes_fit_in_ram(c));
 853
 854                 if (bbpos_cmp(start, BBPOS_MIN) ||
 855                     bbpos_cmp(end, BBPOS_MAX)) {
 856                         struct printbuf buf = PRINTBUF;
 857
 858                         prt_str(&buf, "check_backpointers_to_extents(): ");
 859                         bch2_bbpos_to_text(&buf, start);
 860                         prt_str(&buf, "-");
 861                         bch2_bbpos_to_text(&buf, end);
 862
 863                         bch_verbose(c, "%s", buf.buf);
 864                         printbuf_exit(&buf);
 865                 }
 866
 867                 ret = bch2_check_backpointers_to_extents_pass(&trans, start, end);
 868                 if (ret || !bbpos_cmp(end, BBPOS_MAX))
 869                         break;
 870
 871                 start = bbpos_successor(end);
 872         }
 873         bch2_trans_exit(&trans);
 874
 875         return ret;
 876 }