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 "error.h"
   9
  10 #include <linux/mm.h>
  11
  12 /*
  13  * Convert from pos in backpointer btree to pos of corresponding bucket in alloc
  14  * btree:
  15  */
  16 static inline struct bpos bp_pos_to_bucket(const struct bch_fs *c,
  17                                            struct bpos bp_pos)
  18 {
  19         struct bch_dev *ca = bch_dev_bkey_exists(c, bp_pos.inode);
  20         u64 bucket_sector = bp_pos.offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT;
  21
  22         return POS(bp_pos.inode, sector_to_bucket(ca, bucket_sector));
  23 }
  24
  25 /*
  26  * Convert from pos in alloc btree + bucket offset to pos in backpointer btree:
  27  */
  28 static inline struct bpos bucket_pos_to_bp(const struct bch_fs *c,
  29                                            struct bpos bucket,
  30                                            u64 bucket_offset)
  31 {
  32         struct bch_dev *ca = bch_dev_bkey_exists(c, bucket.inode);
  33         struct bpos ret;
  34
  35         ret = POS(bucket.inode,
  36                   (bucket_to_sector(ca, bucket.offset) <<
  37                    MAX_EXTENT_COMPRESS_RATIO_SHIFT) + bucket_offset);
  38
  39         BUG_ON(!bkey_eq(bucket, bp_pos_to_bucket(c, ret)));
  40
  41         return ret;
  42 }
  43
  44 static bool extent_matches_bp(struct bch_fs *c,
  45                               enum btree_id btree_id, unsigned level,
  46                               struct bkey_s_c k,
  47                               struct bpos bucket,
  48                               struct bch_backpointer bp)
  49 {
  50         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
  51         const union bch_extent_entry *entry;
  52         struct extent_ptr_decoded p;
  53
  54         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
  55                 struct bpos bucket2;
  56                 struct bch_backpointer bp2;
  57
  58                 if (p.ptr.cached)
  59                         continue;
  60
  61                 bch2_extent_ptr_to_bp(c, btree_id, level, k, p,
  62                                       &bucket2, &bp2);
  63                 if (bpos_eq(bucket, bucket2) &&
  64                     !memcmp(&bp, &bp2, sizeof(bp)))
  65                         return true;
  66         }
  67
  68         return false;
  69 }
  70
  71 int bch2_backpointer_invalid(const struct bch_fs *c, struct bkey_s_c k,
  72                              int rw, struct printbuf *err)
  73 {
  74         struct bkey_s_c_backpointer bp = bkey_s_c_to_backpointer(k);
  75         struct bpos bucket = bp_pos_to_bucket(c, bp.k->p);
  76
  77         if (bkey_val_bytes(bp.k) < sizeof(*bp.v)) {
  78                 prt_str(err, "incorrect value size");
  79                 return -BCH_ERR_invalid_bkey;
  80         }
  81
  82         if (!bpos_eq(bp.k->p, bucket_pos_to_bp(c, bucket, bp.v->bucket_offset))) {
  83                 prt_str(err, "backpointer at wrong pos");
  84                 return -BCH_ERR_invalid_bkey;
  85         }
  86
  87         return 0;
  88 }
  89
  90 void bch2_backpointer_to_text(struct printbuf *out, const struct bch_backpointer *bp)
  91 {
  92         prt_printf(out, "btree=%s l=%u offset=%llu:%u len=%u pos=",
  93                bch2_btree_ids[bp->btree_id],
  94                bp->level,
  95                (u64) (bp->bucket_offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT),
  96                (u32) bp->bucket_offset & ~(~0U << MAX_EXTENT_COMPRESS_RATIO_SHIFT),
  97                bp->bucket_len);
  98         bch2_bpos_to_text(out, bp->pos);
  99 }
 100
 101 void bch2_backpointer_k_to_text(struct printbuf *out, struct bch_fs *c, struct bkey_s_c k)
 102 {
 103         bch2_backpointer_to_text(out, bkey_s_c_to_backpointer(k).v);
 104 }
 105
 106 void bch2_backpointer_swab(struct bkey_s k)
 107 {
 108         struct bkey_s_backpointer bp = bkey_s_to_backpointer(k);
 109
 110         bp.v->bucket_offset     = swab32(bp.v->bucket_offset);
 111         bp.v->bucket_len        = swab32(bp.v->bucket_len);
 112         bch2_bpos_swab(&bp.v->pos);
 113 }
 114
 115 #define BACKPOINTER_OFFSET_MAX  ((1ULL << 40) - 1)
 116
 117 static inline int backpointer_cmp(struct bch_backpointer l, struct bch_backpointer r)
 118 {
 119         return cmp_int(l.bucket_offset, r.bucket_offset);
 120 }
 121
 122 static int bch2_backpointer_del_by_offset(struct btree_trans *trans,
 123                                           struct bpos bucket,
 124                                           u64 bp_offset,
 125                                           struct bch_backpointer bp)
 126 {
 127         struct bch_fs *c = trans->c;
 128         struct btree_iter iter;
 129         struct bkey_s_c k;
 130         int ret;
 131
 132         if (bp_offset < BACKPOINTER_OFFSET_MAX) {
 133                 struct bch_backpointer *bps;
 134                 struct bkey_i_alloc_v4 *a;
 135                 unsigned i, nr;
 136
 137                 bch2_trans_iter_init(trans, &iter, BTREE_ID_alloc,
 138                                      bucket,
 139                                      BTREE_ITER_INTENT|
 140                                      BTREE_ITER_SLOTS|
 141                                      BTREE_ITER_WITH_UPDATES);
 142                 k = bch2_btree_iter_peek_slot(&iter);
 143                 ret = bkey_err(k);
 144                 if (ret)
 145                         goto err;
 146
 147                 if (k.k->type != KEY_TYPE_alloc_v4) {
 148                         ret = -ENOENT;
 149                         goto err;
 150                 }
 151
 152                 a = bch2_alloc_to_v4_mut(trans, k);
 153                 ret = PTR_ERR_OR_ZERO(a);
 154                 if (ret)
 155                         goto err;
 156                 bps = alloc_v4_backpointers(&a->v);
 157                 nr = BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v);
 158
 159                 for (i = 0; i < nr; i++) {
 160                         if (bps[i].bucket_offset == bp_offset)
 161                                 goto found;
 162                         if (bps[i].bucket_offset > bp_offset)
 163                                 break;
 164                 }
 165
 166                 ret = -ENOENT;
 167                 goto err;
 168 found:
 169                 if (memcmp(&bps[i], &bp, sizeof(bp))) {
 170                         ret = -ENOENT;
 171                         goto err;
 172                 }
 173                 array_remove_item(bps, nr, i);
 174                 SET_BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v, nr);
 175                 set_alloc_v4_u64s(a);
 176                 ret = bch2_trans_update(trans, &iter, &a->k_i, 0);
 177         } else {
 178                 bp_offset -= BACKPOINTER_OFFSET_MAX;
 179
 180                 bch2_trans_iter_init(trans, &iter, BTREE_ID_backpointers,
 181                                      bucket_pos_to_bp(c, bucket, bp_offset),
 182                                      BTREE_ITER_INTENT|
 183                                      BTREE_ITER_SLOTS|
 184                                      BTREE_ITER_WITH_UPDATES);
 185                 k = bch2_btree_iter_peek_slot(&iter);
 186                 ret = bkey_err(k);
 187                 if (ret)
 188                         goto err;
 189
 190                 if (k.k->type != KEY_TYPE_backpointer ||
 191                     memcmp(bkey_s_c_to_backpointer(k).v, &bp, sizeof(bp))) {
 192                         ret = -ENOENT;
 193                         goto err;
 194                 }
 195
 196                 ret = bch2_btree_delete_at(trans, &iter, 0);
 197         }
 198 err:
 199         bch2_trans_iter_exit(trans, &iter);
 200         return ret;
 201 }
 202
 203 int bch2_bucket_backpointer_del(struct btree_trans *trans,
 204                                 struct bkey_i_alloc_v4 *a,
 205                                 struct bch_backpointer bp,
 206                                 struct bkey_s_c orig_k)
 207 {
 208         struct bch_fs *c = trans->c;
 209         struct bch_backpointer *bps = alloc_v4_backpointers(&a->v);
 210         unsigned i, nr = BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v);
 211         struct btree_iter bp_iter;
 212         struct bkey_s_c k;
 213         int ret;
 214
 215         for (i = 0; i < nr; i++) {
 216                 int cmp = backpointer_cmp(bps[i], bp) ?:
 217                         memcmp(&bps[i], &bp, sizeof(bp));
 218                 if (!cmp)
 219                         goto found;
 220                 if (cmp >= 0)
 221                         break;
 222         }
 223
 224         goto btree;
 225 found:
 226         array_remove_item(bps, nr, i);
 227         SET_BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v, nr);
 228         set_alloc_v4_u64s(a);
 229         return 0;
 230 btree:
 231         bch2_trans_iter_init(trans, &bp_iter, BTREE_ID_backpointers,
 232                              bucket_pos_to_bp(c, a->k.p, bp.bucket_offset),
 233                              BTREE_ITER_INTENT|
 234                              BTREE_ITER_SLOTS|
 235                              BTREE_ITER_WITH_UPDATES);
 236         k = bch2_btree_iter_peek_slot(&bp_iter);
 237         ret = bkey_err(k);
 238         if (ret)
 239                 goto err;
 240
 241         if (k.k->type != KEY_TYPE_backpointer ||
 242             memcmp(bkey_s_c_to_backpointer(k).v, &bp, sizeof(bp))) {
 243                 struct printbuf buf = PRINTBUF;
 244
 245                 prt_printf(&buf, "backpointer not found when deleting");
 246                 prt_newline(&buf);
 247                 printbuf_indent_add(&buf, 2);
 248
 249                 prt_printf(&buf, "searching for ");
 250                 bch2_backpointer_to_text(&buf, &bp);
 251                 prt_newline(&buf);
 252
 253                 prt_printf(&buf, "got ");
 254                 bch2_bkey_val_to_text(&buf, c, k);
 255                 prt_newline(&buf);
 256
 257                 prt_str(&buf, "alloc ");
 258                 bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&a->k_i));
 259                 prt_newline(&buf);
 260
 261                 prt_printf(&buf, "for ");
 262                 bch2_bkey_val_to_text(&buf, c, orig_k);
 263
 264                 bch_err(c, "%s", buf.buf);
 265                 if (test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags)) {
 266                         bch2_inconsistent_error(c);
 267                         ret = -EIO;
 268                 }
 269                 printbuf_exit(&buf);
 270                 goto err;
 271         }
 272
 273         ret = bch2_btree_delete_at(trans, &bp_iter, 0);
 274 err:
 275         bch2_trans_iter_exit(trans, &bp_iter);
 276         return ret;
 277 }
 278
 279 int bch2_bucket_backpointer_add(struct btree_trans *trans,
 280                                 struct bkey_i_alloc_v4 *a,
 281                                 struct bch_backpointer bp,
 282                                 struct bkey_s_c orig_k)
 283 {
 284         struct bch_fs *c = trans->c;
 285         struct bch_backpointer *bps = alloc_v4_backpointers(&a->v);
 286         unsigned i, nr = BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v);
 287         struct bkey_i_backpointer *bp_k;
 288         struct btree_iter bp_iter;
 289         struct bkey_s_c k;
 290         int ret;
 291
 292         /* Check for duplicates: */
 293         for (i = 0; i < nr; i++) {
 294                 int cmp = backpointer_cmp(bps[i], bp);
 295                 if (cmp >= 0)
 296                         break;
 297         }
 298
 299         if ((i &&
 300              (bps[i - 1].bucket_offset +
 301               bps[i - 1].bucket_len > bp.bucket_offset)) ||
 302             (i < nr &&
 303              (bp.bucket_offset + bp.bucket_len > bps[i].bucket_offset))) {
 304                 struct printbuf buf = PRINTBUF;
 305
 306                 prt_printf(&buf, "overlapping backpointer found when inserting ");
 307                 bch2_backpointer_to_text(&buf, &bp);
 308                 prt_newline(&buf);
 309                 printbuf_indent_add(&buf, 2);
 310
 311                 prt_printf(&buf, "into ");
 312                 bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&a->k_i));
 313                 prt_newline(&buf);
 314
 315                 prt_printf(&buf, "for ");
 316                 bch2_bkey_val_to_text(&buf, c, orig_k);
 317
 318                 bch_err(c, "%s", buf.buf);
 319                 printbuf_exit(&buf);
 320                 if (test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags)) {
 321                         bch2_inconsistent_error(c);
 322                         return -EIO;
 323                 }
 324         }
 325
 326         if (nr < BCH_ALLOC_V4_NR_BACKPOINTERS_MAX) {
 327                 array_insert_item(bps, nr, i, bp);
 328                 SET_BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v, nr);
 329                 set_alloc_v4_u64s(a);
 330                 return 0;
 331         }
 332
 333         /* Overflow: use backpointer btree */
 334
 335         bch2_trans_iter_init(trans, &bp_iter, BTREE_ID_backpointers,
 336                              bucket_pos_to_bp(c, a->k.p, bp.bucket_offset),
 337                              BTREE_ITER_INTENT|
 338                              BTREE_ITER_SLOTS|
 339                              BTREE_ITER_WITH_UPDATES);
 340         k = bch2_btree_iter_peek_slot(&bp_iter);
 341         ret = bkey_err(k);
 342         if (ret)
 343                 goto err;
 344
 345         if (k.k->type) {
 346                 struct printbuf buf = PRINTBUF;
 347
 348                 prt_printf(&buf, "existing btree backpointer key found when inserting ");
 349                 bch2_backpointer_to_text(&buf, &bp);
 350                 prt_newline(&buf);
 351                 printbuf_indent_add(&buf, 2);
 352
 353                 prt_printf(&buf, "found ");
 354                 bch2_bkey_val_to_text(&buf, c, k);
 355                 prt_newline(&buf);
 356
 357                 prt_printf(&buf, "for ");
 358                 bch2_bkey_val_to_text(&buf, c, orig_k);
 359
 360                 bch_err(c, "%s", buf.buf);
 361                 printbuf_exit(&buf);
 362                 if (test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags)) {
 363                         bch2_inconsistent_error(c);
 364                         ret = -EIO;
 365                         goto err;
 366                 }
 367         }
 368
 369         bp_k = bch2_bkey_alloc(trans, &bp_iter, backpointer);
 370         ret = PTR_ERR_OR_ZERO(bp_k);
 371         if (ret)
 372                 goto err;
 373
 374         bp_k->v = bp;
 375
 376         ret = bch2_trans_update(trans, &bp_iter, &bp_k->k_i, 0);
 377 err:
 378         bch2_trans_iter_exit(trans, &bp_iter);
 379         return ret;
 380 }
 381
 382 /*
 383  * Find the next backpointer >= *bp_offset:
 384  */
 385 int bch2_get_next_backpointer(struct btree_trans *trans,
 386                               struct bpos bucket, int gen,
 387                               u64 *bp_offset,
 388                               struct bch_backpointer *dst,
 389                               unsigned iter_flags)
 390 {
 391         struct bch_fs *c = trans->c;
 392         struct bpos bp_pos, bp_end_pos;
 393         struct btree_iter alloc_iter, bp_iter = { NULL };
 394         struct bkey_s_c k;
 395         struct bkey_s_c_alloc_v4 a;
 396         size_t i;
 397         int ret;
 398
 399         if (*bp_offset == U64_MAX)
 400                 return 0;
 401
 402         bp_pos = bucket_pos_to_bp(c, bucket,
 403                                   max(*bp_offset, BACKPOINTER_OFFSET_MAX) - BACKPOINTER_OFFSET_MAX);
 404         bp_end_pos = bucket_pos_to_bp(c, bpos_nosnap_successor(bucket), 0);
 405
 406         bch2_trans_iter_init(trans, &alloc_iter, BTREE_ID_alloc,
 407                              bucket, BTREE_ITER_CACHED);
 408         k = bch2_btree_iter_peek_slot(&alloc_iter);
 409         ret = bkey_err(k);
 410         if (ret)
 411                 goto out;
 412
 413         if (k.k->type != KEY_TYPE_alloc_v4)
 414                 goto done;
 415
 416         a = bkey_s_c_to_alloc_v4(k);
 417         if (gen >= 0 && a.v->gen != gen)
 418                 goto done;
 419
 420         for (i = 0; i < BCH_ALLOC_V4_NR_BACKPOINTERS(a.v); i++) {
 421                 if (alloc_v4_backpointers_c(a.v)[i].bucket_offset < *bp_offset)
 422                         continue;
 423
 424                 *dst = alloc_v4_backpointers_c(a.v)[i];
 425                 *bp_offset = dst->bucket_offset;
 426                 goto out;
 427         }
 428
 429         for_each_btree_key_norestart(trans, bp_iter, BTREE_ID_backpointers,
 430                                      bp_pos, 0, k, ret) {
 431                 if (bpos_ge(k.k->p, bp_end_pos))
 432                         break;
 433
 434                 if (k.k->type != KEY_TYPE_backpointer)
 435                         continue;
 436
 437                 *dst = *bkey_s_c_to_backpointer(k).v;
 438                 *bp_offset = dst->bucket_offset + BACKPOINTER_OFFSET_MAX;
 439                 goto out;
 440         }
 441 done:
 442         *bp_offset = U64_MAX;
 443 out:
 444         bch2_trans_iter_exit(trans, &bp_iter);
 445         bch2_trans_iter_exit(trans, &alloc_iter);
 446         return ret;
 447 }
 448
 449 static void backpointer_not_found(struct btree_trans *trans,
 450                                   struct bpos bucket,
 451                                   u64 bp_offset,
 452                                   struct bch_backpointer bp,
 453                                   struct bkey_s_c k,
 454                                   const char *thing_it_points_to)
 455 {
 456         struct bch_fs *c = trans->c;
 457         struct printbuf buf = PRINTBUF;
 458
 459         prt_printf(&buf, "backpointer doesn't match %s it points to:\n  ",
 460                    thing_it_points_to);
 461         prt_printf(&buf, "bucket: ");
 462         bch2_bpos_to_text(&buf, bucket);
 463         prt_printf(&buf, "\n  ");
 464
 465         if (bp_offset >= BACKPOINTER_OFFSET_MAX) {
 466                 struct bpos bp_pos =
 467                         bucket_pos_to_bp(c, bucket,
 468                                         bp_offset - BACKPOINTER_OFFSET_MAX);
 469                 prt_printf(&buf, "backpointer pos: ");
 470                 bch2_bpos_to_text(&buf, bp_pos);
 471                 prt_printf(&buf, "\n  ");
 472         }
 473
 474         bch2_backpointer_to_text(&buf, &bp);
 475         prt_printf(&buf, "\n  ");
 476         bch2_bkey_val_to_text(&buf, c, k);
 477         if (!test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags))
 478                 bch_err_ratelimited(c, "%s", buf.buf);
 479         else
 480                 bch2_trans_inconsistent(trans, "%s", buf.buf);
 481
 482         printbuf_exit(&buf);
 483 }
 484
 485 struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *trans,
 486                                          struct btree_iter *iter,
 487                                          struct bpos bucket,
 488                                          u64 bp_offset,
 489                                          struct bch_backpointer bp)
 490 {
 491         struct bch_fs *c = trans->c;
 492         struct bkey_s_c k;
 493
 494         bch2_trans_node_iter_init(trans, iter,
 495                                   bp.btree_id,
 496                                   bp.pos,
 497                                   0,
 498                                   min(bp.level, c->btree_roots[bp.btree_id].level),
 499                                   0);
 500         k = bch2_btree_iter_peek_slot(iter);
 501         if (bkey_err(k)) {
 502                 bch2_trans_iter_exit(trans, iter);
 503                 return k;
 504         }
 505
 506         if (bp.level == c->btree_roots[bp.btree_id].level + 1)
 507                 k = bkey_i_to_s_c(&c->btree_roots[bp.btree_id].key);
 508
 509         if (k.k && extent_matches_bp(c, bp.btree_id, bp.level, k, bucket, bp))
 510                 return k;
 511
 512         bch2_trans_iter_exit(trans, iter);
 513
 514         if (bp.level) {
 515                 struct btree *b;
 516
 517                 /*
 518                  * If a backpointer for a btree node wasn't found, it may be
 519                  * because it was overwritten by a new btree node that hasn't
 520                  * been written out yet - backpointer_get_node() checks for
 521                  * this:
 522                  */
 523                 b = bch2_backpointer_get_node(trans, iter, bucket, bp_offset, bp);
 524                 if (!IS_ERR_OR_NULL(b))
 525                         return bkey_i_to_s_c(&b->key);
 526
 527                 bch2_trans_iter_exit(trans, iter);
 528
 529                 if (IS_ERR(b))
 530                         return bkey_s_c_err(PTR_ERR(b));
 531                 return bkey_s_c_null;
 532         }
 533
 534         backpointer_not_found(trans, bucket, bp_offset, bp, k, "extent");
 535         return bkey_s_c_null;
 536 }
 537
 538 struct btree *bch2_backpointer_get_node(struct btree_trans *trans,
 539                                         struct btree_iter *iter,
 540                                         struct bpos bucket,
 541                                         u64 bp_offset,
 542                                         struct bch_backpointer bp)
 543 {
 544         struct bch_fs *c = trans->c;
 545         struct btree *b;
 546
 547         BUG_ON(!bp.level);
 548
 549         bch2_trans_node_iter_init(trans, iter,
 550                                   bp.btree_id,
 551                                   bp.pos,
 552                                   0,
 553                                   bp.level - 1,
 554                                   0);
 555         b = bch2_btree_iter_peek_node(iter);
 556         if (IS_ERR(b))
 557                 goto err;
 558
 559         if (b && extent_matches_bp(c, bp.btree_id, bp.level,
 560                                    bkey_i_to_s_c(&b->key),
 561                                    bucket, bp))
 562                 return b;
 563
 564         if (b && btree_node_will_make_reachable(b)) {
 565                 b = ERR_PTR(-BCH_ERR_backpointer_to_overwritten_btree_node);
 566         } else {
 567                 backpointer_not_found(trans, bucket, bp_offset, bp,
 568                                       bkey_i_to_s_c(&b->key), "btree node");
 569                 b = NULL;
 570         }
 571 err:
 572         bch2_trans_iter_exit(trans, iter);
 573         return b;
 574 }
 575
 576 static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_iter *bp_iter,
 577                                         struct bkey_s_c k)
 578 {
 579         struct bch_fs *c = trans->c;
 580         struct btree_iter alloc_iter = { NULL };
 581         struct bch_dev *ca;
 582         struct bkey_s_c alloc_k;
 583         struct printbuf buf = PRINTBUF;
 584         int ret = 0;
 585
 586         if (fsck_err_on(!bch2_dev_exists2(c, k.k->p.inode), c,
 587                         "backpointer for mising device:\n%s",
 588                         (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
 589                 ret = bch2_btree_delete_at(trans, bp_iter, 0);
 590                 goto out;
 591         }
 592
 593         ca = bch_dev_bkey_exists(c, k.k->p.inode);
 594
 595         bch2_trans_iter_init(trans, &alloc_iter, BTREE_ID_alloc,
 596                              bp_pos_to_bucket(c, k.k->p), 0);
 597
 598         alloc_k = bch2_btree_iter_peek_slot(&alloc_iter);
 599         ret = bkey_err(alloc_k);
 600         if (ret)
 601                 goto out;
 602
 603         if (fsck_err_on(alloc_k.k->type != KEY_TYPE_alloc_v4, c,
 604                         "backpointer for nonexistent alloc key: %llu:%llu:0\n%s",
 605                         alloc_iter.pos.inode, alloc_iter.pos.offset,
 606                         (bch2_bkey_val_to_text(&buf, c, alloc_k), buf.buf))) {
 607                 ret = bch2_btree_delete_at(trans, bp_iter, 0);
 608                 goto out;
 609         }
 610 out:
 611 fsck_err:
 612         bch2_trans_iter_exit(trans, &alloc_iter);
 613         printbuf_exit(&buf);
 614         return ret;
 615 }
 616
 617 /* verify that every backpointer has a corresponding alloc key */
 618 int bch2_check_btree_backpointers(struct bch_fs *c)
 619 {
 620         struct btree_iter iter;
 621         struct bkey_s_c k;
 622
 623         return bch2_trans_run(c,
 624                 for_each_btree_key_commit(&trans, iter,
 625                         BTREE_ID_backpointers, POS_MIN, 0, k,
 626                         NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
 627                   bch2_check_btree_backpointer(&trans, &iter, k)));
 628 }
 629
 630 static int check_bp_exists(struct btree_trans *trans,
 631                            struct bpos bucket_pos,
 632                            struct bch_backpointer bp,
 633                            struct bkey_s_c orig_k,
 634                            struct bpos bucket_start,
 635                            struct bpos bucket_end)
 636 {
 637         struct bch_fs *c = trans->c;
 638         struct btree_iter alloc_iter, bp_iter = { NULL };
 639         struct printbuf buf = PRINTBUF;
 640         struct bkey_s_c alloc_k, bp_k;
 641         int ret;
 642
 643         if (bpos_lt(bucket_pos, bucket_start) ||
 644             bpos_gt(bucket_pos, bucket_end))
 645                 return 0;
 646
 647         bch2_trans_iter_init(trans, &alloc_iter, BTREE_ID_alloc, bucket_pos, 0);
 648         alloc_k = bch2_btree_iter_peek_slot(&alloc_iter);
 649         ret = bkey_err(alloc_k);
 650         if (ret)
 651                 goto err;
 652
 653         if (alloc_k.k->type == KEY_TYPE_alloc_v4) {
 654                 struct bkey_s_c_alloc_v4 a = bkey_s_c_to_alloc_v4(alloc_k);
 655                 const struct bch_backpointer *bps = alloc_v4_backpointers_c(a.v);
 656                 unsigned i, nr = BCH_ALLOC_V4_NR_BACKPOINTERS(a.v);
 657
 658                 for (i = 0; i < nr; i++) {
 659                         int cmp = backpointer_cmp(bps[i], bp) ?:
 660                                 memcmp(&bps[i], &bp, sizeof(bp));
 661                         if (!cmp)
 662                                 goto out;
 663                         if (cmp >= 0)
 664                                 break;
 665                 }
 666         } else {
 667                 goto missing;
 668         }
 669
 670         bch2_trans_iter_init(trans, &bp_iter, BTREE_ID_backpointers,
 671                              bucket_pos_to_bp(c, bucket_pos, bp.bucket_offset),
 672                              0);
 673         bp_k = bch2_btree_iter_peek_slot(&bp_iter);
 674         ret = bkey_err(bp_k);
 675         if (ret)
 676                 goto err;
 677
 678         if (bp_k.k->type != KEY_TYPE_backpointer ||
 679             memcmp(bkey_s_c_to_backpointer(bp_k).v, &bp, sizeof(bp)))
 680                 goto missing;
 681 out:
 682 err:
 683 fsck_err:
 684         bch2_trans_iter_exit(trans, &bp_iter);
 685         bch2_trans_iter_exit(trans, &alloc_iter);
 686         printbuf_exit(&buf);
 687         return ret;
 688 missing:
 689         prt_printf(&buf, "missing backpointer for btree=%s l=%u ",
 690                bch2_btree_ids[bp.btree_id], bp.level);
 691         bch2_bkey_val_to_text(&buf, c, orig_k);
 692         prt_printf(&buf, "\nin alloc key ");
 693         bch2_bkey_val_to_text(&buf, c, alloc_k);
 694
 695         if (c->sb.version < bcachefs_metadata_version_backpointers ||
 696             c->opts.reconstruct_alloc ||
 697             fsck_err(c, "%s", buf.buf)) {
 698                 struct bkey_i_alloc_v4 *a = bch2_alloc_to_v4_mut(trans, alloc_k);
 699
 700                 ret   = PTR_ERR_OR_ZERO(a) ?:
 701                         bch2_bucket_backpointer_add(trans, a, bp, orig_k) ?:
 702                         bch2_trans_update(trans, &alloc_iter, &a->k_i, 0);
 703         }
 704
 705         goto out;
 706 }
 707
 708 static int check_extent_to_backpointers(struct btree_trans *trans,
 709                                         struct btree_iter *iter,
 710                                         struct bpos bucket_start,
 711                                         struct bpos bucket_end)
 712 {
 713         struct bch_fs *c = trans->c;
 714         struct bkey_ptrs_c ptrs;
 715         const union bch_extent_entry *entry;
 716         struct extent_ptr_decoded p;
 717         struct bkey_s_c k;
 718         int ret;
 719
 720         k = bch2_btree_iter_peek_all_levels(iter);
 721         ret = bkey_err(k);
 722         if (ret)
 723                 return ret;
 724         if (!k.k)
 725                 return 0;
 726
 727         ptrs = bch2_bkey_ptrs_c(k);
 728         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 729                 struct bpos bucket_pos;
 730                 struct bch_backpointer bp;
 731
 732                 if (p.ptr.cached)
 733                         continue;
 734
 735                 bch2_extent_ptr_to_bp(c, iter->btree_id, iter->path->level,
 736                                       k, p, &bucket_pos, &bp);
 737
 738                 ret = check_bp_exists(trans, bucket_pos, bp, k, bucket_start, bucket_end);
 739                 if (ret)
 740                         return ret;
 741         }
 742
 743         return 0;
 744 }
 745
 746 static int check_btree_root_to_backpointers(struct btree_trans *trans,
 747                                             enum btree_id btree_id,
 748                                             struct bpos bucket_start,
 749                                             struct bpos bucket_end)
 750 {
 751         struct bch_fs *c = trans->c;
 752         struct btree_iter iter;
 753         struct btree *b;
 754         struct bkey_s_c k;
 755         struct bkey_ptrs_c ptrs;
 756         struct extent_ptr_decoded p;
 757         const union bch_extent_entry *entry;
 758         int ret;
 759
 760         bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN, 0,
 761                                   c->btree_roots[btree_id].level, 0);
 762         b = bch2_btree_iter_peek_node(&iter);
 763         ret = PTR_ERR_OR_ZERO(b);
 764         if (ret)
 765                 goto err;
 766
 767         BUG_ON(b != btree_node_root(c, b));
 768
 769         k = bkey_i_to_s_c(&b->key);
 770         ptrs = bch2_bkey_ptrs_c(k);
 771         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 772                 struct bpos bucket_pos;
 773                 struct bch_backpointer bp;
 774
 775                 if (p.ptr.cached)
 776                         continue;
 777
 778                 bch2_extent_ptr_to_bp(c, iter.btree_id, iter.path->level + 1,
 779                                       k, p, &bucket_pos, &bp);
 780
 781                 ret = check_bp_exists(trans, bucket_pos, bp, k, bucket_start, bucket_end);
 782                 if (ret)
 783                         goto err;
 784         }
 785 err:
 786         bch2_trans_iter_exit(trans, &iter);
 787         return ret;
 788 }
 789
 790 static inline struct bbpos bp_to_bbpos(struct bch_backpointer bp)
 791 {
 792         return (struct bbpos) {
 793                 .btree  = bp.btree_id,
 794                 .pos    = bp.pos,
 795         };
 796 }
 797
 798 static size_t btree_nodes_fit_in_ram(struct bch_fs *c)
 799 {
 800         struct sysinfo i;
 801         u64 mem_bytes;
 802
 803         si_meminfo(&i);
 804         mem_bytes = i.totalram * i.mem_unit;
 805         return (mem_bytes >> 1) / btree_bytes(c);
 806 }
 807
 808 int bch2_get_btree_in_memory_pos(struct btree_trans *trans,
 809                                  unsigned btree_leaf_mask,
 810                                  unsigned btree_interior_mask,
 811                                  struct bbpos start, struct bbpos *end)
 812 {
 813         struct btree_iter iter;
 814         struct bkey_s_c k;
 815         size_t btree_nodes = btree_nodes_fit_in_ram(trans->c);
 816         enum btree_id btree;
 817         int ret = 0;
 818
 819         for (btree = start.btree; btree < BTREE_ID_NR && !ret; btree++) {
 820                 unsigned depth = ((1U << btree) & btree_leaf_mask) ? 1 : 2;
 821
 822                 if (!((1U << btree) & btree_leaf_mask) &&
 823                     !((1U << btree) & btree_interior_mask))
 824                         continue;
 825
 826                 bch2_trans_node_iter_init(trans, &iter, btree,
 827                                           btree == start.btree ? start.pos : POS_MIN,
 828                                           0, depth, 0);
 829                 /*
 830                  * for_each_btree_key_contineu() doesn't check the return value
 831                  * from bch2_btree_iter_advance(), which is needed when
 832                  * iterating over interior nodes where we'll see keys at
 833                  * SPOS_MAX:
 834                  */
 835                 do {
 836                         k = __bch2_btree_iter_peek_and_restart(trans, &iter, 0);
 837                         ret = bkey_err(k);
 838                         if (!k.k || ret)
 839                                 break;
 840
 841                         --btree_nodes;
 842                         if (!btree_nodes) {
 843                                 *end = BBPOS(btree, k.k->p);
 844                                 bch2_trans_iter_exit(trans, &iter);
 845                                 return 0;
 846                         }
 847                 } while (bch2_btree_iter_advance(&iter));
 848                 bch2_trans_iter_exit(trans, &iter);
 849         }
 850
 851         *end = BBPOS_MAX;
 852         return ret;
 853 }
 854
 855 static int bch2_check_extents_to_backpointers_pass(struct btree_trans *trans,
 856                                                    struct bpos bucket_start,
 857                                                    struct bpos bucket_end)
 858 {
 859         struct btree_iter iter;
 860         enum btree_id btree_id;
 861         int ret = 0;
 862
 863         for (btree_id = 0; btree_id < BTREE_ID_NR; btree_id++) {
 864                 unsigned depth = btree_type_has_ptrs(btree_id) ? 0 : 1;
 865
 866                 bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN, 0,
 867                                           depth,
 868                                           BTREE_ITER_ALL_LEVELS|
 869                                           BTREE_ITER_PREFETCH);
 870
 871                 do {
 872                         ret = commit_do(trans, NULL, NULL,
 873                                         BTREE_INSERT_LAZY_RW|
 874                                         BTREE_INSERT_NOFAIL,
 875                                         check_extent_to_backpointers(trans, &iter,
 876                                                                 bucket_start, bucket_end));
 877                         if (ret)
 878                                 break;
 879                 } while (!bch2_btree_iter_advance(&iter));
 880
 881                 bch2_trans_iter_exit(trans, &iter);
 882
 883                 if (ret)
 884                         break;
 885
 886                 ret = commit_do(trans, NULL, NULL,
 887                                 BTREE_INSERT_LAZY_RW|
 888                                 BTREE_INSERT_NOFAIL,
 889                                 check_btree_root_to_backpointers(trans, btree_id,
 890                                                         bucket_start, bucket_end));
 891                 if (ret)
 892                         break;
 893         }
 894         return ret;
 895 }
 896
 897 static struct bpos bucket_pos_to_bp_safe(const struct bch_fs *c,
 898                                          struct bpos bucket)
 899 {
 900         return bch2_dev_exists2(c, bucket.inode)
 901                 ? bucket_pos_to_bp(c, bucket, 0)
 902                 : bucket;
 903 }
 904
 905 int bch2_get_alloc_in_memory_pos(struct btree_trans *trans,
 906                                  struct bpos start, struct bpos *end)
 907 {
 908         struct btree_iter alloc_iter;
 909         struct btree_iter bp_iter;
 910         struct bkey_s_c alloc_k, bp_k;
 911         size_t btree_nodes = btree_nodes_fit_in_ram(trans->c);
 912         bool alloc_end = false, bp_end = false;
 913         int ret = 0;
 914
 915         bch2_trans_node_iter_init(trans, &alloc_iter, BTREE_ID_alloc,
 916                                   start, 0, 1, 0);
 917         bch2_trans_node_iter_init(trans, &bp_iter, BTREE_ID_backpointers,
 918                                   bucket_pos_to_bp_safe(trans->c, start), 0, 1, 0);
 919         while (1) {
 920                 alloc_k = !alloc_end
 921                         ? __bch2_btree_iter_peek_and_restart(trans, &alloc_iter, 0)
 922                         : bkey_s_c_null;
 923                 bp_k = !bp_end
 924                         ? __bch2_btree_iter_peek_and_restart(trans, &bp_iter, 0)
 925                         : bkey_s_c_null;
 926
 927                 ret = bkey_err(alloc_k) ?: bkey_err(bp_k);
 928                 if ((!alloc_k.k && !bp_k.k) || ret) {
 929                         *end = SPOS_MAX;
 930                         break;
 931                 }
 932
 933                 --btree_nodes;
 934                 if (!btree_nodes) {
 935                         *end = alloc_k.k->p;
 936                         break;
 937                 }
 938
 939                 if (bpos_lt(alloc_iter.pos, SPOS_MAX) &&
 940                     bpos_lt(bucket_pos_to_bp_safe(trans->c, alloc_iter.pos), bp_iter.pos)) {
 941                         if (!bch2_btree_iter_advance(&alloc_iter))
 942                                 alloc_end = true;
 943                 } else {
 944                         if (!bch2_btree_iter_advance(&bp_iter))
 945                                 bp_end = true;
 946                 }
 947         }
 948         bch2_trans_iter_exit(trans, &bp_iter);
 949         bch2_trans_iter_exit(trans, &alloc_iter);
 950         return ret;
 951 }
 952
 953 int bch2_check_extents_to_backpointers(struct bch_fs *c)
 954 {
 955         struct btree_trans trans;
 956         struct bpos start = POS_MIN, end;
 957         int ret;
 958
 959         bch2_trans_init(&trans, c, 0, 0);
 960         while (1) {
 961                 ret = bch2_get_alloc_in_memory_pos(&trans, start, &end);
 962                 if (ret)
 963                         break;
 964
 965                 if (bpos_eq(start, POS_MIN) && !bpos_eq(end, SPOS_MAX))
 966                         bch_verbose(c, "%s(): alloc info does not fit in ram, running in multiple passes with %zu nodes per pass",
 967                                     __func__, btree_nodes_fit_in_ram(c));
 968
 969                 if (!bpos_eq(start, POS_MIN) || !bpos_eq(end, SPOS_MAX)) {
 970                         struct printbuf buf = PRINTBUF;
 971
 972                         prt_str(&buf, "check_extents_to_backpointers(): ");
 973                         bch2_bpos_to_text(&buf, start);
 974                         prt_str(&buf, "-");
 975                         bch2_bpos_to_text(&buf, end);
 976
 977                         bch_verbose(c, "%s", buf.buf);
 978                         printbuf_exit(&buf);
 979                 }
 980
 981                 ret = bch2_check_extents_to_backpointers_pass(&trans, start, end);
 982                 if (ret || bpos_eq(end, SPOS_MAX))
 983                         break;
 984
 985                 start = bpos_successor(end);
 986         }
 987         bch2_trans_exit(&trans);
 988
 989         return ret;
 990 }
 991
 992 static int check_one_backpointer(struct btree_trans *trans,
 993                                  struct bpos bucket,
 994                                  u64 *bp_offset,
 995                                  struct bbpos start,
 996                                  struct bbpos end)
 997 {
 998         struct btree_iter iter;
 999         struct bch_backpointer bp;
1000         struct bbpos pos;
1001         struct bkey_s_c k;
1002         struct printbuf buf = PRINTBUF;
1003         int ret;
1004
1005         ret = bch2_get_next_backpointer(trans, bucket, -1, bp_offset, &bp, 0);
1006         if (ret || *bp_offset == U64_MAX)
1007                 return ret;
1008
1009         pos = bp_to_bbpos(bp);
1010         if (bbpos_cmp(pos, start) < 0 ||
1011             bbpos_cmp(pos, end) > 0)
1012                 return 0;
1013
1014         k = bch2_backpointer_get_key(trans, &iter, bucket, *bp_offset, bp);
1015         ret = bkey_err(k);
1016         if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node)
1017                 return 0;
1018         if (ret)
1019                 return ret;
1020
1021         if (fsck_err_on(!k.k, trans->c,
1022                         "%s backpointer points to missing extent\n%s",
1023                         *bp_offset < BACKPOINTER_OFFSET_MAX ? "alloc" : "btree",
1024                         (bch2_backpointer_to_text(&buf, &bp), buf.buf))) {
1025                 ret = bch2_backpointer_del_by_offset(trans, bucket, *bp_offset, bp);
1026                 if (ret == -ENOENT)
1027                         bch_err(trans->c, "backpointer at %llu not found", *bp_offset);
1028         }
1029
1030         bch2_trans_iter_exit(trans, &iter);
1031 fsck_err:
1032         printbuf_exit(&buf);
1033         return ret;
1034 }
1035
1036 static int bch2_check_backpointers_to_extents_pass(struct btree_trans *trans,
1037                                                    struct bbpos start,
1038                                                    struct bbpos end)
1039 {
1040         struct btree_iter iter;
1041         struct bkey_s_c k;
1042         int ret = 0;
1043
1044         for_each_btree_key(trans, iter, BTREE_ID_alloc, POS_MIN,
1045                            BTREE_ITER_PREFETCH, k, ret) {
1046                 u64 bp_offset = 0;
1047
1048                 while (!(ret = commit_do(trans, NULL, NULL,
1049                                          BTREE_INSERT_LAZY_RW|
1050                                          BTREE_INSERT_NOFAIL,
1051                                 check_one_backpointer(trans, iter.pos, &bp_offset, start, end))) &&
1052                        bp_offset < U64_MAX)
1053                         bp_offset++;
1054
1055                 if (ret)
1056                         break;
1057         }
1058         bch2_trans_iter_exit(trans, &iter);
1059         return ret < 0 ? ret : 0;
1060 }
1061
1062 int bch2_check_backpointers_to_extents(struct bch_fs *c)
1063 {
1064         struct btree_trans trans;
1065         struct bbpos start = (struct bbpos) { .btree = 0, .pos = POS_MIN, }, end;
1066         int ret;
1067
1068         bch2_trans_init(&trans, c, 0, 0);
1069         while (1) {
1070                 ret = bch2_get_btree_in_memory_pos(&trans,
1071                                                    (1U << BTREE_ID_extents)|
1072                                                    (1U << BTREE_ID_reflink),
1073                                                    ~0,
1074                                                    start, &end);
1075                 if (ret)
1076                         break;
1077
1078                 if (!bbpos_cmp(start, BBPOS_MIN) &&
1079                     bbpos_cmp(end, BBPOS_MAX))
1080                         bch_verbose(c, "%s(): extents do not fit in ram, running in multiple passes with %zu nodes per pass",
1081                                     __func__, btree_nodes_fit_in_ram(c));
1082
1083                 if (bbpos_cmp(start, BBPOS_MIN) ||
1084                     bbpos_cmp(end, BBPOS_MAX)) {
1085                         struct printbuf buf = PRINTBUF;
1086
1087                         prt_str(&buf, "check_backpointers_to_extents(): ");
1088                         bch2_bbpos_to_text(&buf, start);
1089                         prt_str(&buf, "-");
1090                         bch2_bbpos_to_text(&buf, end);
1091
1092                         bch_verbose(c, "%s", buf.buf);
1093                         printbuf_exit(&buf);
1094                 }
1095
1096                 ret = bch2_check_backpointers_to_extents_pass(&trans, start, end);
1097                 if (ret || !bbpos_cmp(end, BBPOS_MAX))
1098                         break;
1099
1100                 start = bbpos_successor(end);
1101         }
1102         bch2_trans_exit(&trans);
1103
1104         return ret;
1105 }