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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 "bkey_buf.h"
7#include "btree_cache.h"
8#include "btree_update.h"
9#include "btree_update_interior.h"
10#include "btree_write_buffer.h"
11#include "error.h"
12
13#include <linux/mm.h>
14
15static bool extent_matches_bp(struct bch_fs *c,
16 enum btree_id btree_id, unsigned level,
17 struct bkey_s_c k,
18 struct bpos bucket,
19 struct bch_backpointer bp)
20{
21 struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
22 const union bch_extent_entry *entry;
23 struct extent_ptr_decoded p;
24
25 bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
26 struct bpos bucket2;
27 struct bch_backpointer bp2;
28
29 if (p.ptr.cached)
30 continue;
31
32 bch2_extent_ptr_to_bp(c, btree_id, level, k, p,
33 &bucket2, &bp2);
34 if (bpos_eq(bucket, bucket2) &&
35 !memcmp(&bp, &bp2, sizeof(bp)))
36 return true;
37 }
38
39 return false;
40}
41
42int bch2_backpointer_invalid(struct bch_fs *c, struct bkey_s_c k,
43 enum bkey_invalid_flags flags,
44 struct printbuf *err)
45{
46 struct bkey_s_c_backpointer bp = bkey_s_c_to_backpointer(k);
47 struct bpos bucket = bp_pos_to_bucket(c, bp.k->p);
48 int ret = 0;
49
50 bkey_fsck_err_on(!bpos_eq(bp.k->p, bucket_pos_to_bp(c, bucket, bp.v->bucket_offset)),
51 c, err,
52 backpointer_pos_wrong,
53 "backpointer at wrong pos");
54fsck_err:
55 return ret;
56}
57
58void bch2_backpointer_to_text(struct printbuf *out, const struct bch_backpointer *bp)
59{
60 prt_printf(out, "btree=%s l=%u offset=%llu:%u len=%u pos=",
61 bch2_btree_id_str(bp->btree_id),
62 bp->level,
63 (u64) (bp->bucket_offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT),
64 (u32) bp->bucket_offset & ~(~0U << MAX_EXTENT_COMPRESS_RATIO_SHIFT),
65 bp->bucket_len);
66 bch2_bpos_to_text(out, bp->pos);
67}
68
69void bch2_backpointer_k_to_text(struct printbuf *out, struct bch_fs *c, struct bkey_s_c k)
70{
71 if (bch2_dev_exists2(c, k.k->p.inode)) {
72 prt_str(out, "bucket=");
73 bch2_bpos_to_text(out, bp_pos_to_bucket(c, k.k->p));
74 prt_str(out, " ");
75 }
76
77 bch2_backpointer_to_text(out, bkey_s_c_to_backpointer(k).v);
78}
79
80void bch2_backpointer_swab(struct bkey_s k)
81{
82 struct bkey_s_backpointer bp = bkey_s_to_backpointer(k);
83
84 bp.v->bucket_offset = swab40(bp.v->bucket_offset);
85 bp.v->bucket_len = swab32(bp.v->bucket_len);
86 bch2_bpos_swab(&bp.v->pos);
87}
88
89static noinline int backpointer_mod_err(struct btree_trans *trans,
90 struct bch_backpointer bp,
91 struct bkey_s_c bp_k,
92 struct bkey_s_c orig_k,
93 bool insert)
94{
95 struct bch_fs *c = trans->c;
96 struct printbuf buf = PRINTBUF;
97
98 if (insert) {
99 prt_printf(&buf, "existing backpointer found when inserting ");
100 bch2_backpointer_to_text(&buf, &bp);
101 prt_newline(&buf);
102 printbuf_indent_add(&buf, 2);
103
104 prt_printf(&buf, "found ");
105 bch2_bkey_val_to_text(&buf, c, bp_k);
106 prt_newline(&buf);
107
108 prt_printf(&buf, "for ");
109 bch2_bkey_val_to_text(&buf, c, orig_k);
110
111 bch_err(c, "%s", buf.buf);
112 } else if (c->curr_recovery_pass > BCH_RECOVERY_PASS_check_extents_to_backpointers) {
113 prt_printf(&buf, "backpointer not found when deleting");
114 prt_newline(&buf);
115 printbuf_indent_add(&buf, 2);
116
117 prt_printf(&buf, "searching for ");
118 bch2_backpointer_to_text(&buf, &bp);
119 prt_newline(&buf);
120
121 prt_printf(&buf, "got ");
122 bch2_bkey_val_to_text(&buf, c, bp_k);
123 prt_newline(&buf);
124
125 prt_printf(&buf, "for ");
126 bch2_bkey_val_to_text(&buf, c, orig_k);
127
128 bch_err(c, "%s", buf.buf);
129 }
130
131 printbuf_exit(&buf);
132
133 if (c->curr_recovery_pass > BCH_RECOVERY_PASS_check_extents_to_backpointers) {
134 bch2_inconsistent_error(c);
135 return -EIO;
136 } else {
137 return 0;
138 }
139}
140
141int bch2_bucket_backpointer_mod_nowritebuffer(struct btree_trans *trans,
142 struct bpos bucket,
143 struct bch_backpointer bp,
144 struct bkey_s_c orig_k,
145 bool insert)
146{
147 struct btree_iter bp_iter;
148 struct bkey_s_c k;
149 struct bkey_i_backpointer *bp_k;
150 int ret;
151
152 bp_k = bch2_trans_kmalloc_nomemzero(trans, sizeof(struct bkey_i_backpointer));
153 ret = PTR_ERR_OR_ZERO(bp_k);
154 if (ret)
155 return ret;
156
157 bkey_backpointer_init(&bp_k->k_i);
158 bp_k->k.p = bucket_pos_to_bp(trans->c, bucket, bp.bucket_offset);
159 bp_k->v = bp;
160
161 if (!insert) {
162 bp_k->k.type = KEY_TYPE_deleted;
163 set_bkey_val_u64s(&bp_k->k, 0);
164 }
165
166 k = bch2_bkey_get_iter(trans, &bp_iter, BTREE_ID_backpointers,
167 bp_k->k.p,
168 BTREE_ITER_INTENT|
169 BTREE_ITER_SLOTS|
170 BTREE_ITER_WITH_UPDATES);
171 ret = bkey_err(k);
172 if (ret)
173 goto err;
174
175 if (insert
176 ? k.k->type
177 : (k.k->type != KEY_TYPE_backpointer ||
178 memcmp(bkey_s_c_to_backpointer(k).v, &bp, sizeof(bp)))) {
179 ret = backpointer_mod_err(trans, bp, k, orig_k, insert);
180 if (ret)
181 goto err;
182 }
183
184 ret = bch2_trans_update(trans, &bp_iter, &bp_k->k_i, 0);
185err:
186 bch2_trans_iter_exit(trans, &bp_iter);
187 return ret;
188}
189
190/*
191 * Find the next backpointer >= *bp_offset:
192 */
193int bch2_get_next_backpointer(struct btree_trans *trans,
194 struct bpos bucket, int gen,
195 struct bpos *bp_pos,
196 struct bch_backpointer *bp,
197 unsigned iter_flags)
198{
199 struct bch_fs *c = trans->c;
200 struct bpos bp_end_pos = bucket_pos_to_bp(c, bpos_nosnap_successor(bucket), 0);
201 struct btree_iter alloc_iter = { NULL }, bp_iter = { NULL };
202 struct bkey_s_c k;
203 int ret = 0;
204
205 if (bpos_ge(*bp_pos, bp_end_pos))
206 goto done;
207
208 if (gen >= 0) {
209 k = bch2_bkey_get_iter(trans, &alloc_iter, BTREE_ID_alloc,
210 bucket, BTREE_ITER_CACHED|iter_flags);
211 ret = bkey_err(k);
212 if (ret)
213 goto out;
214
215 if (k.k->type != KEY_TYPE_alloc_v4 ||
216 bkey_s_c_to_alloc_v4(k).v->gen != gen)
217 goto done;
218 }
219
220 *bp_pos = bpos_max(*bp_pos, bucket_pos_to_bp(c, bucket, 0));
221
222 for_each_btree_key_norestart(trans, bp_iter, BTREE_ID_backpointers,
223 *bp_pos, iter_flags, k, ret) {
224 if (bpos_ge(k.k->p, bp_end_pos))
225 break;
226
227 *bp_pos = k.k->p;
228 *bp = *bkey_s_c_to_backpointer(k).v;
229 goto out;
230 }
231done:
232 *bp_pos = SPOS_MAX;
233out:
234 bch2_trans_iter_exit(trans, &bp_iter);
235 bch2_trans_iter_exit(trans, &alloc_iter);
236 return ret;
237}
238
239static void backpointer_not_found(struct btree_trans *trans,
240 struct bpos bp_pos,
241 struct bch_backpointer bp,
242 struct bkey_s_c k)
243{
244 struct bch_fs *c = trans->c;
245 struct printbuf buf = PRINTBUF;
246 struct bpos bucket = bp_pos_to_bucket(c, bp_pos);
247
248 /*
249 * If we're using the btree write buffer, the backpointer we were
250 * looking at may have already been deleted - failure to find what it
251 * pointed to is not an error:
252 */
253 if (likely(!bch2_backpointers_no_use_write_buffer))
254 return;
255
256 prt_printf(&buf, "backpointer doesn't match %s it points to:\n ",
257 bp.level ? "btree node" : "extent");
258 prt_printf(&buf, "bucket: ");
259 bch2_bpos_to_text(&buf, bucket);
260 prt_printf(&buf, "\n ");
261
262 prt_printf(&buf, "backpointer pos: ");
263 bch2_bpos_to_text(&buf, bp_pos);
264 prt_printf(&buf, "\n ");
265
266 bch2_backpointer_to_text(&buf, &bp);
267 prt_printf(&buf, "\n ");
268 bch2_bkey_val_to_text(&buf, c, k);
269 if (c->curr_recovery_pass >= BCH_RECOVERY_PASS_check_extents_to_backpointers)
270 bch_err_ratelimited(c, "%s", buf.buf);
271 else
272 bch2_trans_inconsistent(trans, "%s", buf.buf);
273
274 printbuf_exit(&buf);
275}
276
277struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *trans,
278 struct btree_iter *iter,
279 struct bpos bp_pos,
280 struct bch_backpointer bp,
281 unsigned iter_flags)
282{
283 if (likely(!bp.level)) {
284 struct bch_fs *c = trans->c;
285 struct bpos bucket = bp_pos_to_bucket(c, bp_pos);
286 struct bkey_s_c k;
287
288 bch2_trans_node_iter_init(trans, iter,
289 bp.btree_id,
290 bp.pos,
291 0, 0,
292 iter_flags);
293 k = bch2_btree_iter_peek_slot(iter);
294 if (bkey_err(k)) {
295 bch2_trans_iter_exit(trans, iter);
296 return k;
297 }
298
299 if (k.k && extent_matches_bp(c, bp.btree_id, bp.level, k, bucket, bp))
300 return k;
301
302 bch2_trans_iter_exit(trans, iter);
303 backpointer_not_found(trans, bp_pos, bp, k);
304 return bkey_s_c_null;
305 } else {
306 struct btree *b = bch2_backpointer_get_node(trans, iter, bp_pos, bp);
307
308 if (IS_ERR_OR_NULL(b)) {
309 bch2_trans_iter_exit(trans, iter);
310 return IS_ERR(b) ? bkey_s_c_err(PTR_ERR(b)) : bkey_s_c_null;
311 }
312 return bkey_i_to_s_c(&b->key);
313 }
314}
315
316struct btree *bch2_backpointer_get_node(struct btree_trans *trans,
317 struct btree_iter *iter,
318 struct bpos bp_pos,
319 struct bch_backpointer bp)
320{
321 struct bch_fs *c = trans->c;
322 struct bpos bucket = bp_pos_to_bucket(c, bp_pos);
323 struct btree *b;
324
325 BUG_ON(!bp.level);
326
327 bch2_trans_node_iter_init(trans, iter,
328 bp.btree_id,
329 bp.pos,
330 0,
331 bp.level - 1,
332 0);
333 b = bch2_btree_iter_peek_node(iter);
334 if (IS_ERR_OR_NULL(b))
335 goto err;
336
337 BUG_ON(b->c.level != bp.level - 1);
338
339 if (extent_matches_bp(c, bp.btree_id, bp.level,
340 bkey_i_to_s_c(&b->key),
341 bucket, bp))
342 return b;
343
344 if (btree_node_will_make_reachable(b)) {
345 b = ERR_PTR(-BCH_ERR_backpointer_to_overwritten_btree_node);
346 } else {
347 backpointer_not_found(trans, bp_pos, bp, bkey_i_to_s_c(&b->key));
348 b = NULL;
349 }
350err:
351 bch2_trans_iter_exit(trans, iter);
352 return b;
353}
354
355static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_iter *bp_iter,
356 struct bkey_s_c k)
357{
358 struct bch_fs *c = trans->c;
359 struct btree_iter alloc_iter = { NULL };
360 struct bkey_s_c alloc_k;
361 struct printbuf buf = PRINTBUF;
362 int ret = 0;
363
364 if (fsck_err_on(!bch2_dev_exists2(c, k.k->p.inode), c,
365 backpointer_to_missing_device,
366 "backpointer for missing device:\n%s",
367 (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
368 ret = bch2_btree_delete_at(trans, bp_iter, 0);
369 goto out;
370 }
371
372 alloc_k = bch2_bkey_get_iter(trans, &alloc_iter, BTREE_ID_alloc,
373 bp_pos_to_bucket(c, k.k->p), 0);
374 ret = bkey_err(alloc_k);
375 if (ret)
376 goto out;
377
378 if (fsck_err_on(alloc_k.k->type != KEY_TYPE_alloc_v4, c,
379 backpointer_to_missing_alloc,
380 "backpointer for nonexistent alloc key: %llu:%llu:0\n%s",
381 alloc_iter.pos.inode, alloc_iter.pos.offset,
382 (bch2_bkey_val_to_text(&buf, c, alloc_k), buf.buf))) {
383 ret = bch2_btree_delete_at(trans, bp_iter, 0);
384 goto out;
385 }
386out:
387fsck_err:
388 bch2_trans_iter_exit(trans, &alloc_iter);
389 printbuf_exit(&buf);
390 return ret;
391}
392
393/* verify that every backpointer has a corresponding alloc key */
394int bch2_check_btree_backpointers(struct bch_fs *c)
395{
396 int ret = bch2_trans_run(c,
397 for_each_btree_key_commit(trans, iter,
398 BTREE_ID_backpointers, POS_MIN, 0, k,
399 NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
400 bch2_check_btree_backpointer(trans, &iter, k)));
401 bch_err_fn(c, ret);
402 return ret;
403}
404
405static inline bool bkey_and_val_eq(struct bkey_s_c l, struct bkey_s_c r)
406{
407 return bpos_eq(l.k->p, r.k->p) &&
408 bkey_bytes(l.k) == bkey_bytes(r.k) &&
409 !memcmp(l.v, r.v, bkey_val_bytes(l.k));
410}
411
412struct extents_to_bp_state {
413 struct bpos bucket_start;
414 struct bpos bucket_end;
415 struct bkey_buf last_flushed;
416};
417
418static int check_bp_exists(struct btree_trans *trans,
419 struct extents_to_bp_state *s,
420 struct bpos bucket,
421 struct bch_backpointer bp,
422 struct bkey_s_c orig_k)
423{
424 struct bch_fs *c = trans->c;
425 struct btree_iter bp_iter = { NULL };
426 struct printbuf buf = PRINTBUF;
427 struct bkey_s_c bp_k;
428 struct bkey_buf tmp;
429 int ret;
430
431 bch2_bkey_buf_init(&tmp);
432
433 if (bpos_lt(bucket, s->bucket_start) ||
434 bpos_gt(bucket, s->bucket_end))
435 return 0;
436
437 if (!bch2_dev_bucket_exists(c, bucket))
438 goto missing;
439
440 bp_k = bch2_bkey_get_iter(trans, &bp_iter, BTREE_ID_backpointers,
441 bucket_pos_to_bp(c, bucket, bp.bucket_offset),
442 0);
443 ret = bkey_err(bp_k);
444 if (ret)
445 goto err;
446
447 if (bp_k.k->type != KEY_TYPE_backpointer ||
448 memcmp(bkey_s_c_to_backpointer(bp_k).v, &bp, sizeof(bp))) {
449 bch2_bkey_buf_reassemble(&tmp, c, orig_k);
450
451 if (!bkey_and_val_eq(orig_k, bkey_i_to_s_c(s->last_flushed.k))) {
452 if (bp.level) {
453 bch2_trans_unlock(trans);
454 bch2_btree_interior_updates_flush(c);
455 }
456
457 ret = bch2_btree_write_buffer_flush_sync(trans);
458 if (ret)
459 goto err;
460
461 bch2_bkey_buf_copy(&s->last_flushed, c, tmp.k);
462 ret = -BCH_ERR_transaction_restart_write_buffer_flush;
463 goto out;
464 }
465 goto missing;
466 }
467out:
468err:
469fsck_err:
470 bch2_trans_iter_exit(trans, &bp_iter);
471 bch2_bkey_buf_exit(&tmp, c);
472 printbuf_exit(&buf);
473 return ret;
474missing:
475 prt_printf(&buf, "missing backpointer for btree=%s l=%u ",
476 bch2_btree_id_str(bp.btree_id), bp.level);
477 bch2_bkey_val_to_text(&buf, c, orig_k);
478 prt_printf(&buf, "\nbp pos ");
479 bch2_bpos_to_text(&buf, bp_iter.pos);
480
481 if (c->opts.reconstruct_alloc ||
482 fsck_err(c, ptr_to_missing_backpointer, "%s", buf.buf))
483 ret = bch2_bucket_backpointer_mod(trans, bucket, bp, orig_k, true);
484
485 goto out;
486}
487
488static int check_extent_to_backpointers(struct btree_trans *trans,
489 struct extents_to_bp_state *s,
490 enum btree_id btree, unsigned level,
491 struct bkey_s_c k)
492{
493 struct bch_fs *c = trans->c;
494 struct bkey_ptrs_c ptrs;
495 const union bch_extent_entry *entry;
496 struct extent_ptr_decoded p;
497 int ret;
498
499 ptrs = bch2_bkey_ptrs_c(k);
500 bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
501 struct bpos bucket_pos;
502 struct bch_backpointer bp;
503
504 if (p.ptr.cached)
505 continue;
506
507 bch2_extent_ptr_to_bp(c, btree, level,
508 k, p, &bucket_pos, &bp);
509
510 ret = check_bp_exists(trans, s, bucket_pos, bp, k);
511 if (ret)
512 return ret;
513 }
514
515 return 0;
516}
517
518static int check_btree_root_to_backpointers(struct btree_trans *trans,
519 struct extents_to_bp_state *s,
520 enum btree_id btree_id,
521 int *level)
522{
523 struct bch_fs *c = trans->c;
524 struct btree_iter iter;
525 struct btree *b;
526 struct bkey_s_c k;
527 int ret;
528retry:
529 bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN,
530 0, bch2_btree_id_root(c, btree_id)->b->c.level, 0);
531 b = bch2_btree_iter_peek_node(&iter);
532 ret = PTR_ERR_OR_ZERO(b);
533 if (ret)
534 goto err;
535
536 if (b != btree_node_root(c, b)) {
537 bch2_trans_iter_exit(trans, &iter);
538 goto retry;
539 }
540
541 *level = b->c.level;
542
543 k = bkey_i_to_s_c(&b->key);
544 ret = check_extent_to_backpointers(trans, s, btree_id, b->c.level + 1, k);
545err:
546 bch2_trans_iter_exit(trans, &iter);
547 return ret;
548}
549
550static inline struct bbpos bp_to_bbpos(struct bch_backpointer bp)
551{
552 return (struct bbpos) {
553 .btree = bp.btree_id,
554 .pos = bp.pos,
555 };
556}
557
558static size_t btree_nodes_fit_in_ram(struct bch_fs *c)
559{
560 struct sysinfo i;
561 u64 mem_bytes;
562
563 si_meminfo(&i);
564 mem_bytes = i.totalram * i.mem_unit;
565 return div_u64(mem_bytes >> 1, c->opts.btree_node_size);
566}
567
568static int bch2_get_btree_in_memory_pos(struct btree_trans *trans,
569 unsigned btree_leaf_mask,
570 unsigned btree_interior_mask,
571 struct bbpos start, struct bbpos *end)
572{
573 struct btree_iter iter;
574 struct bkey_s_c k;
575 size_t btree_nodes = btree_nodes_fit_in_ram(trans->c);
576 enum btree_id btree;
577 int ret = 0;
578
579 for (btree = start.btree; btree < BTREE_ID_NR && !ret; btree++) {
580 unsigned depth = ((1U << btree) & btree_leaf_mask) ? 1 : 2;
581
582 if (!((1U << btree) & btree_leaf_mask) &&
583 !((1U << btree) & btree_interior_mask))
584 continue;
585
586 bch2_trans_node_iter_init(trans, &iter, btree,
587 btree == start.btree ? start.pos : POS_MIN,
588 0, depth, 0);
589 /*
590 * for_each_btree_key_contineu() doesn't check the return value
591 * from bch2_btree_iter_advance(), which is needed when
592 * iterating over interior nodes where we'll see keys at
593 * SPOS_MAX:
594 */
595 do {
596 k = __bch2_btree_iter_peek_and_restart(trans, &iter, 0);
597 ret = bkey_err(k);
598 if (!k.k || ret)
599 break;
600
601 --btree_nodes;
602 if (!btree_nodes) {
603 *end = BBPOS(btree, k.k->p);
604 bch2_trans_iter_exit(trans, &iter);
605 return 0;
606 }
607 } while (bch2_btree_iter_advance(&iter));
608 bch2_trans_iter_exit(trans, &iter);
609 }
610
611 *end = BBPOS_MAX;
612 return ret;
613}
614
615static int bch2_check_extents_to_backpointers_pass(struct btree_trans *trans,
616 struct extents_to_bp_state *s)
617{
618 struct bch_fs *c = trans->c;
619 int ret = 0;
620
621 for (enum btree_id btree_id = 0;
622 btree_id < btree_id_nr_alive(c);
623 btree_id++) {
624 int level, depth = btree_type_has_ptrs(btree_id) ? 0 : 1;
625
626 ret = commit_do(trans, NULL, NULL,
627 BCH_TRANS_COMMIT_no_enospc,
628 check_btree_root_to_backpointers(trans, s, btree_id, &level));
629 if (ret)
630 return ret;
631
632 while (level >= depth) {
633 struct btree_iter iter;
634 bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN, 0,
635 level,
636 BTREE_ITER_PREFETCH);
637 while (1) {
638 bch2_trans_begin(trans);
639
640 struct bkey_s_c k = bch2_btree_iter_peek(&iter);
641 if (!k.k)
642 break;
643 ret = bkey_err(k) ?:
644 check_extent_to_backpointers(trans, s, btree_id, level, k) ?:
645 bch2_trans_commit(trans, NULL, NULL,
646 BCH_TRANS_COMMIT_no_enospc);
647 if (bch2_err_matches(ret, BCH_ERR_transaction_restart)) {
648 ret = 0;
649 continue;
650 }
651 if (ret)
652 break;
653 if (bpos_eq(iter.pos, SPOS_MAX))
654 break;
655 bch2_btree_iter_advance(&iter);
656 }
657 bch2_trans_iter_exit(trans, &iter);
658
659 if (ret)
660 return ret;
661
662 --level;
663 }
664 }
665
666 return 0;
667}
668
669static struct bpos bucket_pos_to_bp_safe(const struct bch_fs *c,
670 struct bpos bucket)
671{
672 return bch2_dev_exists2(c, bucket.inode)
673 ? bucket_pos_to_bp(c, bucket, 0)
674 : bucket;
675}
676
677static int bch2_get_alloc_in_memory_pos(struct btree_trans *trans,
678 struct bpos start, struct bpos *end)
679{
680 struct btree_iter alloc_iter;
681 struct btree_iter bp_iter;
682 struct bkey_s_c alloc_k, bp_k;
683 size_t btree_nodes = btree_nodes_fit_in_ram(trans->c);
684 bool alloc_end = false, bp_end = false;
685 int ret = 0;
686
687 bch2_trans_node_iter_init(trans, &alloc_iter, BTREE_ID_alloc,
688 start, 0, 1, 0);
689 bch2_trans_node_iter_init(trans, &bp_iter, BTREE_ID_backpointers,
690 bucket_pos_to_bp_safe(trans->c, start), 0, 1, 0);
691 while (1) {
692 alloc_k = !alloc_end
693 ? __bch2_btree_iter_peek_and_restart(trans, &alloc_iter, 0)
694 : bkey_s_c_null;
695 bp_k = !bp_end
696 ? __bch2_btree_iter_peek_and_restart(trans, &bp_iter, 0)
697 : bkey_s_c_null;
698
699 ret = bkey_err(alloc_k) ?: bkey_err(bp_k);
700 if ((!alloc_k.k && !bp_k.k) || ret) {
701 *end = SPOS_MAX;
702 break;
703 }
704
705 --btree_nodes;
706 if (!btree_nodes) {
707 *end = alloc_k.k ? alloc_k.k->p : SPOS_MAX;
708 break;
709 }
710
711 if (bpos_lt(alloc_iter.pos, SPOS_MAX) &&
712 bpos_lt(bucket_pos_to_bp_safe(trans->c, alloc_iter.pos), bp_iter.pos)) {
713 if (!bch2_btree_iter_advance(&alloc_iter))
714 alloc_end = true;
715 } else {
716 if (!bch2_btree_iter_advance(&bp_iter))
717 bp_end = true;
718 }
719 }
720 bch2_trans_iter_exit(trans, &bp_iter);
721 bch2_trans_iter_exit(trans, &alloc_iter);
722 return ret;
723}
724
725int bch2_check_extents_to_backpointers(struct bch_fs *c)
726{
727 struct btree_trans *trans = bch2_trans_get(c);
728 struct extents_to_bp_state s = { .bucket_start = POS_MIN };
729 int ret;
730
731 bch2_bkey_buf_init(&s.last_flushed);
732 bkey_init(&s.last_flushed.k->k);
733
734 while (1) {
735 ret = bch2_get_alloc_in_memory_pos(trans, s.bucket_start, &s.bucket_end);
736 if (ret)
737 break;
738
739 if ( bpos_eq(s.bucket_start, POS_MIN) &&
740 !bpos_eq(s.bucket_end, SPOS_MAX))
741 bch_verbose(c, "%s(): alloc info does not fit in ram, running in multiple passes with %zu nodes per pass",
742 __func__, btree_nodes_fit_in_ram(c));
743
744 if (!bpos_eq(s.bucket_start, POS_MIN) ||
745 !bpos_eq(s.bucket_end, SPOS_MAX)) {
746 struct printbuf buf = PRINTBUF;
747
748 prt_str(&buf, "check_extents_to_backpointers(): ");
749 bch2_bpos_to_text(&buf, s.bucket_start);
750 prt_str(&buf, "-");
751 bch2_bpos_to_text(&buf, s.bucket_end);
752
753 bch_verbose(c, "%s", buf.buf);
754 printbuf_exit(&buf);
755 }
756
757 ret = bch2_check_extents_to_backpointers_pass(trans, &s);
758 if (ret || bpos_eq(s.bucket_end, SPOS_MAX))
759 break;
760
761 s.bucket_start = bpos_successor(s.bucket_end);
762 }
763 bch2_trans_put(trans);
764 bch2_bkey_buf_exit(&s.last_flushed, c);
765
766 bch_err_fn(c, ret);
767 return ret;
768}
769
770static int check_one_backpointer(struct btree_trans *trans,
771 struct bbpos start,
772 struct bbpos end,
773 struct bkey_s_c_backpointer bp,
774 struct bpos *last_flushed_pos)
775{
776 struct bch_fs *c = trans->c;
777 struct btree_iter iter;
778 struct bbpos pos = bp_to_bbpos(*bp.v);
779 struct bkey_s_c k;
780 struct printbuf buf = PRINTBUF;
781 int ret;
782
783 if (bbpos_cmp(pos, start) < 0 ||
784 bbpos_cmp(pos, end) > 0)
785 return 0;
786
787 k = bch2_backpointer_get_key(trans, &iter, bp.k->p, *bp.v, 0);
788 ret = bkey_err(k);
789 if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node)
790 return 0;
791 if (ret)
792 return ret;
793
794 if (!k.k && !bpos_eq(*last_flushed_pos, bp.k->p)) {
795 *last_flushed_pos = bp.k->p;
796 ret = bch2_btree_write_buffer_flush_sync(trans) ?:
797 -BCH_ERR_transaction_restart_write_buffer_flush;
798 goto out;
799 }
800
801 if (fsck_err_on(!k.k, c,
802 backpointer_to_missing_ptr,
803 "backpointer for missing %s\n %s",
804 bp.v->level ? "btree node" : "extent",
805 (bch2_bkey_val_to_text(&buf, c, bp.s_c), buf.buf))) {
806 ret = bch2_btree_delete_at_buffered(trans, BTREE_ID_backpointers, bp.k->p);
807 goto out;
808 }
809out:
810fsck_err:
811 bch2_trans_iter_exit(trans, &iter);
812 printbuf_exit(&buf);
813 return ret;
814}
815
816static int bch2_check_backpointers_to_extents_pass(struct btree_trans *trans,
817 struct bbpos start,
818 struct bbpos end)
819{
820 struct bpos last_flushed_pos = SPOS_MAX;
821
822 return for_each_btree_key_commit(trans, iter, BTREE_ID_backpointers,
823 POS_MIN, BTREE_ITER_PREFETCH, k,
824 NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
825 check_one_backpointer(trans, start, end,
826 bkey_s_c_to_backpointer(k),
827 &last_flushed_pos));
828}
829
830int bch2_check_backpointers_to_extents(struct bch_fs *c)
831{
832 struct btree_trans *trans = bch2_trans_get(c);
833 struct bbpos start = (struct bbpos) { .btree = 0, .pos = POS_MIN, }, end;
834 int ret;
835
836 while (1) {
837 ret = bch2_get_btree_in_memory_pos(trans,
838 (1U << BTREE_ID_extents)|
839 (1U << BTREE_ID_reflink),
840 ~0,
841 start, &end);
842 if (ret)
843 break;
844
845 if (!bbpos_cmp(start, BBPOS_MIN) &&
846 bbpos_cmp(end, BBPOS_MAX))
847 bch_verbose(c, "%s(): extents do not fit in ram, running in multiple passes with %zu nodes per pass",
848 __func__, btree_nodes_fit_in_ram(c));
849
850 if (bbpos_cmp(start, BBPOS_MIN) ||
851 bbpos_cmp(end, BBPOS_MAX)) {
852 struct printbuf buf = PRINTBUF;
853
854 prt_str(&buf, "check_backpointers_to_extents(): ");
855 bch2_bbpos_to_text(&buf, start);
856 prt_str(&buf, "-");
857 bch2_bbpos_to_text(&buf, end);
858
859 bch_verbose(c, "%s", buf.buf);
860 printbuf_exit(&buf);
861 }
862
863 ret = bch2_check_backpointers_to_extents_pass(trans, start, end);
864 if (ret || !bbpos_cmp(end, BBPOS_MAX))
865 break;
866
867 start = bbpos_successor(end);
868 }
869 bch2_trans_put(trans);
870
871 bch_err_fn(c, ret);
872 return ret;
873}