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                 if (!test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags))
 246                         goto err;
 247
 248                 prt_printf(&buf, "backpointer not found when deleting");
 249                 prt_newline(&buf);
 250                 printbuf_indent_add(&buf, 2);
 251
 252                 prt_printf(&buf, "searching for ");
 253                 bch2_backpointer_to_text(&buf, &bp);
 254                 prt_newline(&buf);
 255
 256                 prt_printf(&buf, "got ");
 257                 bch2_bkey_val_to_text(&buf, c, k);
 258                 prt_newline(&buf);
 259
 260                 prt_str(&buf, "alloc ");
 261                 bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&a->k_i));
 262                 prt_newline(&buf);
 263
 264                 prt_printf(&buf, "for ");
 265                 bch2_bkey_val_to_text(&buf, c, orig_k);
 266
 267                 bch_err(c, "%s", buf.buf);
 268                 bch2_inconsistent_error(c);
 269                 ret = -EIO;
 270                 printbuf_exit(&buf);
 271                 goto err;
 272         }
 273
 274         ret = bch2_btree_delete_at(trans, &bp_iter, 0);
 275 err:
 276         bch2_trans_iter_exit(trans, &bp_iter);
 277         return ret;
 278 }
 279
 280 int bch2_bucket_backpointer_add(struct btree_trans *trans,
 281                                 struct bkey_i_alloc_v4 *a,
 282                                 struct bch_backpointer bp,
 283                                 struct bkey_s_c orig_k)
 284 {
 285         struct bch_fs *c = trans->c;
 286         struct bch_backpointer *bps = alloc_v4_backpointers(&a->v);
 287         unsigned i, nr = BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v);
 288         struct bkey_i_backpointer *bp_k;
 289         struct btree_iter bp_iter;
 290         struct bkey_s_c k;
 291         int ret;
 292
 293         /* Check for duplicates: */
 294         for (i = 0; i < nr; i++) {
 295                 int cmp = backpointer_cmp(bps[i], bp);
 296                 if (cmp >= 0)
 297                         break;
 298         }
 299
 300         if ((i &&
 301              (bps[i - 1].bucket_offset +
 302               bps[i - 1].bucket_len > bp.bucket_offset)) ||
 303             (i < nr &&
 304              (bp.bucket_offset + bp.bucket_len > bps[i].bucket_offset))) {
 305                 struct printbuf buf = PRINTBUF;
 306
 307                 prt_printf(&buf, "overlapping backpointer found when inserting ");
 308                 bch2_backpointer_to_text(&buf, &bp);
 309                 prt_newline(&buf);
 310                 printbuf_indent_add(&buf, 2);
 311
 312                 prt_printf(&buf, "into ");
 313                 bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&a->k_i));
 314                 prt_newline(&buf);
 315
 316                 prt_printf(&buf, "for ");
 317                 bch2_bkey_val_to_text(&buf, c, orig_k);
 318
 319                 bch_err(c, "%s", buf.buf);
 320                 printbuf_exit(&buf);
 321                 if (test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags)) {
 322                         bch2_inconsistent_error(c);
 323                         return -EIO;
 324                 }
 325         }
 326
 327         if (nr < BCH_ALLOC_V4_NR_BACKPOINTERS_MAX) {
 328                 array_insert_item(bps, nr, i, bp);
 329                 SET_BCH_ALLOC_V4_NR_BACKPOINTERS(&a->v, nr);
 330                 set_alloc_v4_u64s(a);
 331                 return 0;
 332         }
 333
 334         /* Overflow: use backpointer btree */
 335
 336         bch2_trans_iter_init(trans, &bp_iter, BTREE_ID_backpointers,
 337                              bucket_pos_to_bp(c, a->k.p, bp.bucket_offset),
 338                              BTREE_ITER_INTENT|
 339                              BTREE_ITER_SLOTS|
 340                              BTREE_ITER_WITH_UPDATES);
 341         k = bch2_btree_iter_peek_slot(&bp_iter);
 342         ret = bkey_err(k);
 343         if (ret)
 344                 goto err;
 345
 346         if (k.k->type) {
 347                 struct printbuf buf = PRINTBUF;
 348
 349                 prt_printf(&buf, "existing btree backpointer key found when inserting ");
 350                 bch2_backpointer_to_text(&buf, &bp);
 351                 prt_newline(&buf);
 352                 printbuf_indent_add(&buf, 2);
 353
 354                 prt_printf(&buf, "found ");
 355                 bch2_bkey_val_to_text(&buf, c, k);
 356                 prt_newline(&buf);
 357
 358                 prt_printf(&buf, "for ");
 359                 bch2_bkey_val_to_text(&buf, c, orig_k);
 360
 361                 bch_err(c, "%s", buf.buf);
 362                 printbuf_exit(&buf);
 363                 if (test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags)) {
 364                         bch2_inconsistent_error(c);
 365                         ret = -EIO;
 366                         goto err;
 367                 }
 368         }
 369
 370         bp_k = bch2_bkey_alloc(trans, &bp_iter, backpointer);
 371         ret = PTR_ERR_OR_ZERO(bp_k);
 372         if (ret)
 373                 goto err;
 374
 375         bp_k->v = bp;
 376
 377         ret = bch2_trans_update(trans, &bp_iter, &bp_k->k_i, 0);
 378 err:
 379         bch2_trans_iter_exit(trans, &bp_iter);
 380         return ret;
 381 }
 382
 383 /*
 384  * Find the next backpointer >= *bp_offset:
 385  */
 386 int bch2_get_next_backpointer(struct btree_trans *trans,
 387                               struct bpos bucket, int gen,
 388                               u64 *bp_offset,
 389                               struct bch_backpointer *dst,
 390                               unsigned iter_flags)
 391 {
 392         struct bch_fs *c = trans->c;
 393         struct bpos bp_pos, bp_end_pos;
 394         struct btree_iter alloc_iter, bp_iter = { NULL };
 395         struct bkey_s_c k;
 396         struct bkey_s_c_alloc_v4 a;
 397         size_t i;
 398         int ret;
 399
 400         if (*bp_offset == U64_MAX)
 401                 return 0;
 402
 403         bp_pos = bucket_pos_to_bp(c, bucket,
 404                                   max(*bp_offset, BACKPOINTER_OFFSET_MAX) - BACKPOINTER_OFFSET_MAX);
 405         bp_end_pos = bucket_pos_to_bp(c, bpos_nosnap_successor(bucket), 0);
 406
 407         bch2_trans_iter_init(trans, &alloc_iter, BTREE_ID_alloc,
 408                              bucket, BTREE_ITER_CACHED);
 409         k = bch2_btree_iter_peek_slot(&alloc_iter);
 410         ret = bkey_err(k);
 411         if (ret)
 412                 goto out;
 413
 414         if (k.k->type != KEY_TYPE_alloc_v4)
 415                 goto done;
 416
 417         a = bkey_s_c_to_alloc_v4(k);
 418         if (gen >= 0 && a.v->gen != gen)
 419                 goto done;
 420
 421         for (i = 0; i < BCH_ALLOC_V4_NR_BACKPOINTERS(a.v); i++) {
 422                 if (alloc_v4_backpointers_c(a.v)[i].bucket_offset < *bp_offset)
 423                         continue;
 424
 425                 *dst = alloc_v4_backpointers_c(a.v)[i];
 426                 *bp_offset = dst->bucket_offset;
 427                 goto out;
 428         }
 429
 430         for_each_btree_key_norestart(trans, bp_iter, BTREE_ID_backpointers,
 431                                      bp_pos, 0, k, ret) {
 432                 if (bpos_ge(k.k->p, bp_end_pos))
 433                         break;
 434
 435                 if (k.k->type != KEY_TYPE_backpointer)
 436                         continue;
 437
 438                 *dst = *bkey_s_c_to_backpointer(k).v;
 439                 *bp_offset = dst->bucket_offset + BACKPOINTER_OFFSET_MAX;
 440                 goto out;
 441         }
 442 done:
 443         *bp_offset = U64_MAX;
 444 out:
 445         bch2_trans_iter_exit(trans, &bp_iter);
 446         bch2_trans_iter_exit(trans, &alloc_iter);
 447         return ret;
 448 }
 449
 450 static void backpointer_not_found(struct btree_trans *trans,
 451                                   struct bpos bucket,
 452                                   u64 bp_offset,
 453                                   struct bch_backpointer bp,
 454                                   struct bkey_s_c k,
 455                                   const char *thing_it_points_to)
 456 {
 457         struct bch_fs *c = trans->c;
 458         struct printbuf buf = PRINTBUF;
 459
 460         prt_printf(&buf, "backpointer doesn't match %s it points to:\n  ",
 461                    thing_it_points_to);
 462         prt_printf(&buf, "bucket: ");
 463         bch2_bpos_to_text(&buf, bucket);
 464         prt_printf(&buf, "\n  ");
 465
 466         if (bp_offset >= BACKPOINTER_OFFSET_MAX) {
 467                 struct bpos bp_pos =
 468                         bucket_pos_to_bp(c, bucket,
 469                                         bp_offset - BACKPOINTER_OFFSET_MAX);
 470                 prt_printf(&buf, "backpointer pos: ");
 471                 bch2_bpos_to_text(&buf, bp_pos);
 472                 prt_printf(&buf, "\n  ");
 473         }
 474
 475         bch2_backpointer_to_text(&buf, &bp);
 476         prt_printf(&buf, "\n  ");
 477         bch2_bkey_val_to_text(&buf, c, k);
 478         if (!test_bit(BCH_FS_CHECK_BACKPOINTERS_DONE, &c->flags))
 479                 bch_err_ratelimited(c, "%s", buf.buf);
 480         else
 481                 bch2_trans_inconsistent(trans, "%s", buf.buf);
 482
 483         printbuf_exit(&buf);
 484 }
 485
 486 struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *trans,
 487                                          struct btree_iter *iter,
 488                                          struct bpos bucket,
 489                                          u64 bp_offset,
 490                                          struct bch_backpointer bp)
 491 {
 492         struct bch_fs *c = trans->c;
 493         struct bkey_s_c k;
 494
 495         bch2_trans_node_iter_init(trans, iter,
 496                                   bp.btree_id,
 497                                   bp.pos,
 498                                   0,
 499                                   min(bp.level, c->btree_roots[bp.btree_id].level),
 500                                   0);
 501         k = bch2_btree_iter_peek_slot(iter);
 502         if (bkey_err(k)) {
 503                 bch2_trans_iter_exit(trans, iter);
 504                 return k;
 505         }
 506
 507         if (bp.level == c->btree_roots[bp.btree_id].level + 1)
 508                 k = bkey_i_to_s_c(&c->btree_roots[bp.btree_id].key);
 509
 510         if (k.k && extent_matches_bp(c, bp.btree_id, bp.level, k, bucket, bp))
 511                 return k;
 512
 513         bch2_trans_iter_exit(trans, iter);
 514
 515         if (bp.level) {
 516                 struct btree *b;
 517
 518                 /*
 519                  * If a backpointer for a btree node wasn't found, it may be
 520                  * because it was overwritten by a new btree node that hasn't
 521                  * been written out yet - backpointer_get_node() checks for
 522                  * this:
 523                  */
 524                 b = bch2_backpointer_get_node(trans, iter, bucket, bp_offset, bp);
 525                 if (!IS_ERR_OR_NULL(b))
 526                         return bkey_i_to_s_c(&b->key);
 527
 528                 bch2_trans_iter_exit(trans, iter);
 529
 530                 if (IS_ERR(b))
 531                         return bkey_s_c_err(PTR_ERR(b));
 532                 return bkey_s_c_null;
 533         }
 534
 535         backpointer_not_found(trans, bucket, bp_offset, bp, k, "extent");
 536         return bkey_s_c_null;
 537 }
 538
 539 struct btree *bch2_backpointer_get_node(struct btree_trans *trans,
 540                                         struct btree_iter *iter,
 541                                         struct bpos bucket,
 542                                         u64 bp_offset,
 543                                         struct bch_backpointer bp)
 544 {
 545         struct bch_fs *c = trans->c;
 546         struct btree *b;
 547
 548         BUG_ON(!bp.level);
 549
 550         bch2_trans_node_iter_init(trans, iter,
 551                                   bp.btree_id,
 552                                   bp.pos,
 553                                   0,
 554                                   bp.level - 1,
 555                                   0);
 556         b = bch2_btree_iter_peek_node(iter);
 557         if (IS_ERR(b))
 558                 goto err;
 559
 560         if (b && extent_matches_bp(c, bp.btree_id, bp.level,
 561                                    bkey_i_to_s_c(&b->key),
 562                                    bucket, bp))
 563                 return b;
 564
 565         if (b && btree_node_will_make_reachable(b)) {
 566                 b = ERR_PTR(-BCH_ERR_backpointer_to_overwritten_btree_node);
 567         } else {
 568                 backpointer_not_found(trans, bucket, bp_offset, bp,
 569                                       bkey_i_to_s_c(&b->key), "btree node");
 570                 b = NULL;
 571         }
 572 err:
 573         bch2_trans_iter_exit(trans, iter);
 574         return b;
 575 }
 576
 577 static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_iter *bp_iter,
 578                                         struct bkey_s_c k)
 579 {
 580         struct bch_fs *c = trans->c;
 581         struct btree_iter alloc_iter = { NULL };
 582         struct bch_dev *ca;
 583         struct bkey_s_c alloc_k;
 584         struct printbuf buf = PRINTBUF;
 585         int ret = 0;
 586
 587         if (fsck_err_on(!bch2_dev_exists2(c, k.k->p.inode), c,
 588                         "backpointer for mising device:\n%s",
 589                         (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
 590                 ret = bch2_btree_delete_at(trans, bp_iter, 0);
 591                 goto out;
 592         }
 593
 594         ca = bch_dev_bkey_exists(c, k.k->p.inode);
 595
 596         bch2_trans_iter_init(trans, &alloc_iter, BTREE_ID_alloc,
 597                              bp_pos_to_bucket(c, k.k->p), 0);
 598
 599         alloc_k = bch2_btree_iter_peek_slot(&alloc_iter);
 600         ret = bkey_err(alloc_k);
 601         if (ret)
 602                 goto out;
 603
 604         if (fsck_err_on(alloc_k.k->type != KEY_TYPE_alloc_v4, c,
 605                         "backpointer for nonexistent alloc key: %llu:%llu:0\n%s",
 606                         alloc_iter.pos.inode, alloc_iter.pos.offset,
 607                         (bch2_bkey_val_to_text(&buf, c, alloc_k), buf.buf))) {
 608                 ret = bch2_btree_delete_at(trans, bp_iter, 0);
 609                 goto out;
 610         }
 611 out:
 612 fsck_err:
 613         bch2_trans_iter_exit(trans, &alloc_iter);
 614         printbuf_exit(&buf);
 615         return ret;
 616 }
 617
 618 /* verify that every backpointer has a corresponding alloc key */
 619 int bch2_check_btree_backpointers(struct bch_fs *c)
 620 {
 621         struct btree_iter iter;
 622         struct bkey_s_c k;
 623
 624         return bch2_trans_run(c,
 625                 for_each_btree_key_commit(&trans, iter,
 626                         BTREE_ID_backpointers, POS_MIN, 0, k,
 627                         NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
 628                   bch2_check_btree_backpointer(&trans, &iter, k)));
 629 }
 630
 631 static int check_bp_exists(struct btree_trans *trans,
 632                            struct bpos bucket_pos,
 633                            struct bch_backpointer bp,
 634                            struct bkey_s_c orig_k,
 635                            struct bpos bucket_start,
 636                            struct bpos bucket_end)
 637 {
 638         struct bch_fs *c = trans->c;
 639         struct btree_iter alloc_iter, bp_iter = { NULL };
 640         struct printbuf buf = PRINTBUF;
 641         struct bkey_s_c alloc_k, bp_k;
 642         int ret;
 643
 644         if (bpos_lt(bucket_pos, bucket_start) ||
 645             bpos_gt(bucket_pos, bucket_end))
 646                 return 0;
 647
 648         bch2_trans_iter_init(trans, &alloc_iter, BTREE_ID_alloc, bucket_pos, 0);
 649         alloc_k = bch2_btree_iter_peek_slot(&alloc_iter);
 650         ret = bkey_err(alloc_k);
 651         if (ret)
 652                 goto err;
 653
 654         if (alloc_k.k->type == KEY_TYPE_alloc_v4) {
 655                 struct bkey_s_c_alloc_v4 a = bkey_s_c_to_alloc_v4(alloc_k);
 656                 const struct bch_backpointer *bps = alloc_v4_backpointers_c(a.v);
 657                 unsigned i, nr = BCH_ALLOC_V4_NR_BACKPOINTERS(a.v);
 658
 659                 for (i = 0; i < nr; i++) {
 660                         int cmp = backpointer_cmp(bps[i], bp) ?:
 661                                 memcmp(&bps[i], &bp, sizeof(bp));
 662                         if (!cmp)
 663                                 goto out;
 664                         if (cmp >= 0)
 665                                 break;
 666                 }
 667         } else {
 668                 goto missing;
 669         }
 670
 671         bch2_trans_iter_init(trans, &bp_iter, BTREE_ID_backpointers,
 672                              bucket_pos_to_bp(c, bucket_pos, bp.bucket_offset),
 673                              0);
 674         bp_k = bch2_btree_iter_peek_slot(&bp_iter);
 675         ret = bkey_err(bp_k);
 676         if (ret)
 677                 goto err;
 678
 679         if (bp_k.k->type != KEY_TYPE_backpointer ||
 680             memcmp(bkey_s_c_to_backpointer(bp_k).v, &bp, sizeof(bp)))
 681                 goto missing;
 682 out:
 683 err:
 684 fsck_err:
 685         bch2_trans_iter_exit(trans, &bp_iter);
 686         bch2_trans_iter_exit(trans, &alloc_iter);
 687         printbuf_exit(&buf);
 688         return ret;
 689 missing:
 690         prt_printf(&buf, "missing backpointer for btree=%s l=%u ",
 691                bch2_btree_ids[bp.btree_id], bp.level);
 692         bch2_bkey_val_to_text(&buf, c, orig_k);
 693         prt_printf(&buf, "\nin alloc key ");
 694         bch2_bkey_val_to_text(&buf, c, alloc_k);
 695
 696         if (c->sb.version < bcachefs_metadata_version_backpointers ||
 697             c->opts.reconstruct_alloc ||
 698             fsck_err(c, "%s", buf.buf)) {
 699                 struct bkey_i_alloc_v4 *a = bch2_alloc_to_v4_mut(trans, alloc_k);
 700
 701                 ret   = PTR_ERR_OR_ZERO(a) ?:
 702                         bch2_bucket_backpointer_add(trans, a, bp, orig_k) ?:
 703                         bch2_trans_update(trans, &alloc_iter, &a->k_i, 0);
 704         }
 705
 706         goto out;
 707 }
 708
 709 static int check_extent_to_backpointers(struct btree_trans *trans,
 710                                         struct btree_iter *iter,
 711                                         struct bpos bucket_start,
 712                                         struct bpos bucket_end)
 713 {
 714         struct bch_fs *c = trans->c;
 715         struct bkey_ptrs_c ptrs;
 716         const union bch_extent_entry *entry;
 717         struct extent_ptr_decoded p;
 718         struct bkey_s_c k;
 719         int ret;
 720
 721         k = bch2_btree_iter_peek_all_levels(iter);
 722         ret = bkey_err(k);
 723         if (ret)
 724                 return ret;
 725         if (!k.k)
 726                 return 0;
 727
 728         ptrs = bch2_bkey_ptrs_c(k);
 729         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 730                 struct bpos bucket_pos;
 731                 struct bch_backpointer bp;
 732
 733                 if (p.ptr.cached)
 734                         continue;
 735
 736                 bch2_extent_ptr_to_bp(c, iter->btree_id, iter->path->level,
 737                                       k, p, &bucket_pos, &bp);
 738
 739                 ret = check_bp_exists(trans, bucket_pos, bp, k, bucket_start, bucket_end);
 740                 if (ret)
 741                         return ret;
 742         }
 743
 744         return 0;
 745 }
 746
 747 static int check_btree_root_to_backpointers(struct btree_trans *trans,
 748                                             enum btree_id btree_id,
 749                                             struct bpos bucket_start,
 750                                             struct bpos bucket_end)
 751 {
 752         struct bch_fs *c = trans->c;
 753         struct btree_iter iter;
 754         struct btree *b;
 755         struct bkey_s_c k;
 756         struct bkey_ptrs_c ptrs;
 757         struct extent_ptr_decoded p;
 758         const union bch_extent_entry *entry;
 759         int ret;
 760
 761         bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN, 0,
 762                                   c->btree_roots[btree_id].level, 0);
 763         b = bch2_btree_iter_peek_node(&iter);
 764         ret = PTR_ERR_OR_ZERO(b);
 765         if (ret)
 766                 goto err;
 767
 768         BUG_ON(b != btree_node_root(c, b));
 769
 770         k = bkey_i_to_s_c(&b->key);
 771         ptrs = bch2_bkey_ptrs_c(k);
 772         bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
 773                 struct bpos bucket_pos;
 774                 struct bch_backpointer bp;
 775
 776                 if (p.ptr.cached)
 777                         continue;
 778
 779                 bch2_extent_ptr_to_bp(c, iter.btree_id, iter.path->level + 1,
 780                                       k, p, &bucket_pos, &bp);
 781
 782                 ret = check_bp_exists(trans, bucket_pos, bp, k, bucket_start, bucket_end);
 783                 if (ret)
 784                         goto err;
 785         }
 786 err:
 787         bch2_trans_iter_exit(trans, &iter);
 788         return ret;
 789 }
 790
 791 static inline struct bbpos bp_to_bbpos(struct bch_backpointer bp)
 792 {
 793         return (struct bbpos) {
 794                 .btree  = bp.btree_id,
 795                 .pos    = bp.pos,
 796         };
 797 }
 798
 799 static size_t btree_nodes_fit_in_ram(struct bch_fs *c)
 800 {
 801         struct sysinfo i;
 802         u64 mem_bytes;
 803
 804         si_meminfo(&i);
 805         mem_bytes = i.totalram * i.mem_unit;
 806         return (mem_bytes >> 1) / btree_bytes(c);
 807 }
 808
 809 int bch2_get_btree_in_memory_pos(struct btree_trans *trans,
 810                                  unsigned btree_leaf_mask,
 811                                  unsigned btree_interior_mask,
 812                                  struct bbpos start, struct bbpos *end)
 813 {
 814         struct btree_iter iter;
 815         struct bkey_s_c k;
 816         size_t btree_nodes = btree_nodes_fit_in_ram(trans->c);
 817         enum btree_id btree;
 818         int ret = 0;
 819
 820         for (btree = start.btree; btree < BTREE_ID_NR && !ret; btree++) {
 821                 unsigned depth = ((1U << btree) & btree_leaf_mask) ? 1 : 2;
 822
 823                 if (!((1U << btree) & btree_leaf_mask) &&
 824                     !((1U << btree) & btree_interior_mask))
 825                         continue;
 826
 827                 bch2_trans_node_iter_init(trans, &iter, btree,
 828                                           btree == start.btree ? start.pos : POS_MIN,
 829                                           0, depth, 0);
 830                 /*
 831                  * for_each_btree_key_contineu() doesn't check the return value
 832                  * from bch2_btree_iter_advance(), which is needed when
 833                  * iterating over interior nodes where we'll see keys at
 834                  * SPOS_MAX:
 835                  */
 836                 do {
 837                         k = __bch2_btree_iter_peek_and_restart(trans, &iter, 0);
 838                         ret = bkey_err(k);
 839                         if (!k.k || ret)
 840                                 break;
 841
 842                         --btree_nodes;
 843                         if (!btree_nodes) {
 844                                 *end = BBPOS(btree, k.k->p);
 845                                 bch2_trans_iter_exit(trans, &iter);
 846                                 return 0;
 847                         }
 848                 } while (bch2_btree_iter_advance(&iter));
 849                 bch2_trans_iter_exit(trans, &iter);
 850         }
 851
 852         *end = BBPOS_MAX;
 853         return ret;
 854 }
 855
 856 static int bch2_check_extents_to_backpointers_pass(struct btree_trans *trans,
 857                                                    struct bpos bucket_start,
 858                                                    struct bpos bucket_end)
 859 {
 860         struct btree_iter iter;
 861         enum btree_id btree_id;
 862         int ret = 0;
 863
 864         for (btree_id = 0; btree_id < BTREE_ID_NR; btree_id++) {
 865                 unsigned depth = btree_type_has_ptrs(btree_id) ? 0 : 1;
 866
 867                 bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN, 0,
 868                                           depth,
 869                                           BTREE_ITER_ALL_LEVELS|
 870                                           BTREE_ITER_PREFETCH);
 871
 872                 do {
 873                         ret = commit_do(trans, NULL, NULL,
 874                                         BTREE_INSERT_LAZY_RW|
 875                                         BTREE_INSERT_NOFAIL,
 876                                         check_extent_to_backpointers(trans, &iter,
 877                                                                 bucket_start, bucket_end));
 878                         if (ret)
 879                                 break;
 880                 } while (!bch2_btree_iter_advance(&iter));
 881
 882                 bch2_trans_iter_exit(trans, &iter);
 883
 884                 if (ret)
 885                         break;
 886
 887                 ret = commit_do(trans, NULL, NULL,
 888                                 BTREE_INSERT_LAZY_RW|
 889                                 BTREE_INSERT_NOFAIL,
 890                                 check_btree_root_to_backpointers(trans, btree_id,
 891                                                         bucket_start, bucket_end));
 892                 if (ret)
 893                         break;
 894         }
 895         return ret;
 896 }
 897
 898 static struct bpos bucket_pos_to_bp_safe(const struct bch_fs *c,
 899                                          struct bpos bucket)
 900 {
 901         return bch2_dev_exists2(c, bucket.inode)
 902                 ? bucket_pos_to_bp(c, bucket, 0)
 903                 : bucket;
 904 }
 905
 906 int bch2_get_alloc_in_memory_pos(struct btree_trans *trans,
 907                                  struct bpos start, struct bpos *end)
 908 {
 909         struct btree_iter alloc_iter;
 910         struct btree_iter bp_iter;
 911         struct bkey_s_c alloc_k, bp_k;
 912         size_t btree_nodes = btree_nodes_fit_in_ram(trans->c);
 913         bool alloc_end = false, bp_end = false;
 914         int ret = 0;
 915
 916         bch2_trans_node_iter_init(trans, &alloc_iter, BTREE_ID_alloc,
 917                                   start, 0, 1, 0);
 918         bch2_trans_node_iter_init(trans, &bp_iter, BTREE_ID_backpointers,
 919                                   bucket_pos_to_bp_safe(trans->c, start), 0, 1, 0);
 920         while (1) {
 921                 alloc_k = !alloc_end
 922                         ? __bch2_btree_iter_peek_and_restart(trans, &alloc_iter, 0)
 923                         : bkey_s_c_null;
 924                 bp_k = !bp_end
 925                         ? __bch2_btree_iter_peek_and_restart(trans, &bp_iter, 0)
 926                         : bkey_s_c_null;
 927
 928                 ret = bkey_err(alloc_k) ?: bkey_err(bp_k);
 929                 if ((!alloc_k.k && !bp_k.k) || ret) {
 930                         *end = SPOS_MAX;
 931                         break;
 932                 }
 933
 934                 --btree_nodes;
 935                 if (!btree_nodes) {
 936                         *end = alloc_k.k->p;
 937                         break;
 938                 }
 939
 940                 if (bpos_lt(alloc_iter.pos, SPOS_MAX) &&
 941                     bpos_lt(bucket_pos_to_bp_safe(trans->c, alloc_iter.pos), bp_iter.pos)) {
 942                         if (!bch2_btree_iter_advance(&alloc_iter))
 943                                 alloc_end = true;
 944                 } else {
 945                         if (!bch2_btree_iter_advance(&bp_iter))
 946                                 bp_end = true;
 947                 }
 948         }
 949         bch2_trans_iter_exit(trans, &bp_iter);
 950         bch2_trans_iter_exit(trans, &alloc_iter);
 951         return ret;
 952 }
 953
 954 int bch2_check_extents_to_backpointers(struct bch_fs *c)
 955 {
 956         struct btree_trans trans;
 957         struct bpos start = POS_MIN, end;
 958         int ret;
 959
 960         bch2_trans_init(&trans, c, 0, 0);
 961         while (1) {
 962                 ret = bch2_get_alloc_in_memory_pos(&trans, start, &end);
 963                 if (ret)
 964                         break;
 965
 966                 if (bpos_eq(start, POS_MIN) && !bpos_eq(end, SPOS_MAX))
 967                         bch_verbose(c, "%s(): alloc info does not fit in ram, running in multiple passes with %zu nodes per pass",
 968                                     __func__, btree_nodes_fit_in_ram(c));
 969
 970                 if (!bpos_eq(start, POS_MIN) || !bpos_eq(end, SPOS_MAX)) {
 971                         struct printbuf buf = PRINTBUF;
 972
 973                         prt_str(&buf, "check_extents_to_backpointers(): ");
 974                         bch2_bpos_to_text(&buf, start);
 975                         prt_str(&buf, "-");
 976                         bch2_bpos_to_text(&buf, end);
 977
 978                         bch_verbose(c, "%s", buf.buf);
 979                         printbuf_exit(&buf);
 980                 }
 981
 982                 ret = bch2_check_extents_to_backpointers_pass(&trans, start, end);
 983                 if (ret || bpos_eq(end, SPOS_MAX))
 984                         break;
 985
 986                 start = bpos_successor(end);
 987         }
 988         bch2_trans_exit(&trans);
 989
 990         return ret;
 991 }
 992
 993 static int check_one_backpointer(struct btree_trans *trans,
 994                                  struct bpos bucket,
 995                                  u64 *bp_offset,
 996                                  struct bbpos start,
 997                                  struct bbpos end)
 998 {
 999         struct btree_iter iter;
1000         struct bch_backpointer bp;
1001         struct bbpos pos;
1002         struct bkey_s_c k;
1003         struct printbuf buf = PRINTBUF;
1004         int ret;
1005
1006         ret = bch2_get_next_backpointer(trans, bucket, -1, bp_offset, &bp, 0);
1007         if (ret || *bp_offset == U64_MAX)
1008                 return ret;
1009
1010         pos = bp_to_bbpos(bp);
1011         if (bbpos_cmp(pos, start) < 0 ||
1012             bbpos_cmp(pos, end) > 0)
1013                 return 0;
1014
1015         k = bch2_backpointer_get_key(trans, &iter, bucket, *bp_offset, bp);
1016         ret = bkey_err(k);
1017         if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node)
1018                 return 0;
1019         if (ret)
1020                 return ret;
1021
1022         if (fsck_err_on(!k.k, trans->c,
1023                         "%s backpointer points to missing extent\n%s",
1024                         *bp_offset < BACKPOINTER_OFFSET_MAX ? "alloc" : "btree",
1025                         (bch2_backpointer_to_text(&buf, &bp), buf.buf))) {
1026                 ret = bch2_backpointer_del_by_offset(trans, bucket, *bp_offset, bp);
1027                 if (ret == -ENOENT)
1028                         bch_err(trans->c, "backpointer at %llu not found", *bp_offset);
1029         }
1030
1031         bch2_trans_iter_exit(trans, &iter);
1032 fsck_err:
1033         printbuf_exit(&buf);
1034         return ret;
1035 }
1036
1037 static int bch2_check_backpointers_to_extents_pass(struct btree_trans *trans,
1038                                                    struct bbpos start,
1039                                                    struct bbpos end)
1040 {
1041         struct btree_iter iter;
1042         struct bkey_s_c k;
1043         int ret = 0;
1044
1045         for_each_btree_key(trans, iter, BTREE_ID_alloc, POS_MIN,
1046                            BTREE_ITER_PREFETCH, k, ret) {
1047                 u64 bp_offset = 0;
1048
1049                 while (!(ret = commit_do(trans, NULL, NULL,
1050                                          BTREE_INSERT_LAZY_RW|
1051                                          BTREE_INSERT_NOFAIL,
1052                                 check_one_backpointer(trans, iter.pos, &bp_offset, start, end))) &&
1053                        bp_offset < U64_MAX)
1054                         bp_offset++;
1055
1056                 if (ret)
1057                         break;
1058         }
1059         bch2_trans_iter_exit(trans, &iter);
1060         return ret < 0 ? ret : 0;
1061 }
1062
1063 int bch2_check_backpointers_to_extents(struct bch_fs *c)
1064 {
1065         struct btree_trans trans;
1066         struct bbpos start = (struct bbpos) { .btree = 0, .pos = POS_MIN, }, end;
1067         int ret;
1068
1069         bch2_trans_init(&trans, c, 0, 0);
1070         while (1) {
1071                 ret = bch2_get_btree_in_memory_pos(&trans,
1072                                                    (1U << BTREE_ID_extents)|
1073                                                    (1U << BTREE_ID_reflink),
1074                                                    ~0,
1075                                                    start, &end);
1076                 if (ret)
1077                         break;
1078
1079                 if (!bbpos_cmp(start, BBPOS_MIN) &&
1080                     bbpos_cmp(end, BBPOS_MAX))
1081                         bch_verbose(c, "%s(): extents do not fit in ram, running in multiple passes with %zu nodes per pass",
1082                                     __func__, btree_nodes_fit_in_ram(c));
1083
1084                 if (bbpos_cmp(start, BBPOS_MIN) ||
1085                     bbpos_cmp(end, BBPOS_MAX)) {
1086                         struct printbuf buf = PRINTBUF;
1087
1088                         prt_str(&buf, "check_backpointers_to_extents(): ");
1089                         bch2_bbpos_to_text(&buf, start);
1090                         prt_str(&buf, "-");
1091                         bch2_bbpos_to_text(&buf, end);
1092
1093                         bch_verbose(c, "%s", buf.buf);
1094                         printbuf_exit(&buf);
1095                 }
1096
1097                 ret = bch2_check_backpointers_to_extents_pass(&trans, start, end);
1098                 if (ret || !bbpos_cmp(end, BBPOS_MAX))
1099                         break;
1100
1101                 start = bbpos_successor(end);
1102         }
1103         bch2_trans_exit(&trans);
1104
1105         return ret;
1106 }