xref: /linux/fs/bcachefs/backpointers.c (revision 6e7fd890f1d6ac83805409e9c346240de2705584)
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 "checksum.h"
12 #include "error.h"
13 
14 #include <linux/mm.h>
15 
16 static bool extent_matches_bp(struct bch_fs *c,
17 			      enum btree_id btree_id, unsigned level,
18 			      struct bkey_s_c k,
19 			      struct bpos bucket,
20 			      struct bch_backpointer bp)
21 {
22 	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
23 	const union bch_extent_entry *entry;
24 	struct extent_ptr_decoded p;
25 
26 	rcu_read_lock();
27 	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
28 		struct bpos bucket2;
29 		struct bch_backpointer bp2;
30 
31 		if (p.ptr.cached)
32 			continue;
33 
34 		struct bch_dev *ca = bch2_dev_rcu(c, p.ptr.dev);
35 		if (!ca)
36 			continue;
37 
38 		bch2_extent_ptr_to_bp(c, ca, btree_id, level, k, p, entry, &bucket2, &bp2);
39 		if (bpos_eq(bucket, bucket2) &&
40 		    !memcmp(&bp, &bp2, sizeof(bp))) {
41 			rcu_read_unlock();
42 			return true;
43 		}
44 	}
45 	rcu_read_unlock();
46 
47 	return false;
48 }
49 
50 int bch2_backpointer_validate(struct bch_fs *c, struct bkey_s_c k,
51 			      enum bch_validate_flags flags)
52 {
53 	struct bkey_s_c_backpointer bp = bkey_s_c_to_backpointer(k);
54 
55 	rcu_read_lock();
56 	struct bch_dev *ca = bch2_dev_rcu(c, bp.k->p.inode);
57 	if (!ca) {
58 		/* these will be caught by fsck */
59 		rcu_read_unlock();
60 		return 0;
61 	}
62 
63 	struct bpos bucket = bp_pos_to_bucket(ca, bp.k->p);
64 	struct bpos bp_pos = bucket_pos_to_bp_noerror(ca, bucket, bp.v->bucket_offset);
65 	rcu_read_unlock();
66 	int ret = 0;
67 
68 	bkey_fsck_err_on((bp.v->bucket_offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT) >= ca->mi.bucket_size ||
69 			 !bpos_eq(bp.k->p, bp_pos),
70 			 c, backpointer_bucket_offset_wrong,
71 			 "backpointer bucket_offset wrong");
72 fsck_err:
73 	return ret;
74 }
75 
76 void bch2_backpointer_to_text(struct printbuf *out, const struct bch_backpointer *bp)
77 {
78 	prt_printf(out, "btree=%s l=%u offset=%llu:%u len=%u pos=",
79 	       bch2_btree_id_str(bp->btree_id),
80 	       bp->level,
81 	       (u64) (bp->bucket_offset >> MAX_EXTENT_COMPRESS_RATIO_SHIFT),
82 	       (u32) bp->bucket_offset & ~(~0U << MAX_EXTENT_COMPRESS_RATIO_SHIFT),
83 	       bp->bucket_len);
84 	bch2_bpos_to_text(out, bp->pos);
85 }
86 
87 void bch2_backpointer_k_to_text(struct printbuf *out, struct bch_fs *c, struct bkey_s_c k)
88 {
89 	rcu_read_lock();
90 	struct bch_dev *ca = bch2_dev_rcu(c, k.k->p.inode);
91 	if (ca) {
92 		struct bpos bucket = bp_pos_to_bucket(ca, k.k->p);
93 		rcu_read_unlock();
94 		prt_str(out, "bucket=");
95 		bch2_bpos_to_text(out, bucket);
96 		prt_str(out, " ");
97 	} else {
98 		rcu_read_unlock();
99 	}
100 
101 	bch2_backpointer_to_text(out, bkey_s_c_to_backpointer(k).v);
102 }
103 
104 void bch2_backpointer_swab(struct bkey_s k)
105 {
106 	struct bkey_s_backpointer bp = bkey_s_to_backpointer(k);
107 
108 	bp.v->bucket_offset	= swab40(bp.v->bucket_offset);
109 	bp.v->bucket_len	= swab32(bp.v->bucket_len);
110 	bch2_bpos_swab(&bp.v->pos);
111 }
112 
113 static noinline int backpointer_mod_err(struct btree_trans *trans,
114 					struct bch_backpointer bp,
115 					struct bkey_s_c bp_k,
116 					struct bkey_s_c orig_k,
117 					bool insert)
118 {
119 	struct bch_fs *c = trans->c;
120 	struct printbuf buf = PRINTBUF;
121 
122 	if (insert) {
123 		prt_printf(&buf, "existing backpointer found when inserting ");
124 		bch2_backpointer_to_text(&buf, &bp);
125 		prt_newline(&buf);
126 		printbuf_indent_add(&buf, 2);
127 
128 		prt_printf(&buf, "found ");
129 		bch2_bkey_val_to_text(&buf, c, bp_k);
130 		prt_newline(&buf);
131 
132 		prt_printf(&buf, "for ");
133 		bch2_bkey_val_to_text(&buf, c, orig_k);
134 
135 		bch_err(c, "%s", buf.buf);
136 	} else if (c->curr_recovery_pass > BCH_RECOVERY_PASS_check_extents_to_backpointers) {
137 		prt_printf(&buf, "backpointer not found when deleting\n");
138 		printbuf_indent_add(&buf, 2);
139 
140 		prt_printf(&buf, "searching for ");
141 		bch2_backpointer_to_text(&buf, &bp);
142 		prt_newline(&buf);
143 
144 		prt_printf(&buf, "got ");
145 		bch2_bkey_val_to_text(&buf, c, bp_k);
146 		prt_newline(&buf);
147 
148 		prt_printf(&buf, "for ");
149 		bch2_bkey_val_to_text(&buf, c, orig_k);
150 
151 		bch_err(c, "%s", buf.buf);
152 	}
153 
154 	printbuf_exit(&buf);
155 
156 	if (c->curr_recovery_pass > BCH_RECOVERY_PASS_check_extents_to_backpointers) {
157 		return bch2_inconsistent_error(c) ? BCH_ERR_erofs_unfixed_errors : 0;
158 	} else {
159 		return 0;
160 	}
161 }
162 
163 int bch2_bucket_backpointer_mod_nowritebuffer(struct btree_trans *trans,
164 				struct bch_dev *ca,
165 				struct bpos bucket,
166 				struct bch_backpointer bp,
167 				struct bkey_s_c orig_k,
168 				bool insert)
169 {
170 	struct btree_iter bp_iter;
171 	struct bkey_s_c k;
172 	struct bkey_i_backpointer *bp_k;
173 	int ret;
174 
175 	bp_k = bch2_trans_kmalloc_nomemzero(trans, sizeof(struct bkey_i_backpointer));
176 	ret = PTR_ERR_OR_ZERO(bp_k);
177 	if (ret)
178 		return ret;
179 
180 	bkey_backpointer_init(&bp_k->k_i);
181 	bp_k->k.p = bucket_pos_to_bp(ca, bucket, bp.bucket_offset);
182 	bp_k->v = bp;
183 
184 	if (!insert) {
185 		bp_k->k.type = KEY_TYPE_deleted;
186 		set_bkey_val_u64s(&bp_k->k, 0);
187 	}
188 
189 	k = bch2_bkey_get_iter(trans, &bp_iter, BTREE_ID_backpointers,
190 			       bp_k->k.p,
191 			       BTREE_ITER_intent|
192 			       BTREE_ITER_slots|
193 			       BTREE_ITER_with_updates);
194 	ret = bkey_err(k);
195 	if (ret)
196 		goto err;
197 
198 	if (insert
199 	    ? k.k->type
200 	    : (k.k->type != KEY_TYPE_backpointer ||
201 	       memcmp(bkey_s_c_to_backpointer(k).v, &bp, sizeof(bp)))) {
202 		ret = backpointer_mod_err(trans, bp, k, orig_k, insert);
203 		if (ret)
204 			goto err;
205 	}
206 
207 	ret = bch2_trans_update(trans, &bp_iter, &bp_k->k_i, 0);
208 err:
209 	bch2_trans_iter_exit(trans, &bp_iter);
210 	return ret;
211 }
212 
213 /*
214  * Find the next backpointer >= *bp_offset:
215  */
216 int bch2_get_next_backpointer(struct btree_trans *trans,
217 			      struct bch_dev *ca,
218 			      struct bpos bucket, int gen,
219 			      struct bpos *bp_pos,
220 			      struct bch_backpointer *bp,
221 			      unsigned iter_flags)
222 {
223 	struct bpos bp_end_pos = bucket_pos_to_bp(ca, bpos_nosnap_successor(bucket), 0);
224 	struct btree_iter alloc_iter = { NULL }, bp_iter = { NULL };
225 	struct bkey_s_c k;
226 	int ret = 0;
227 
228 	if (bpos_ge(*bp_pos, bp_end_pos))
229 		goto done;
230 
231 	if (gen >= 0) {
232 		k = bch2_bkey_get_iter(trans, &alloc_iter, BTREE_ID_alloc,
233 				       bucket, BTREE_ITER_cached|iter_flags);
234 		ret = bkey_err(k);
235 		if (ret)
236 			goto out;
237 
238 		if (k.k->type != KEY_TYPE_alloc_v4 ||
239 		    bkey_s_c_to_alloc_v4(k).v->gen != gen)
240 			goto done;
241 	}
242 
243 	*bp_pos = bpos_max(*bp_pos, bucket_pos_to_bp(ca, bucket, 0));
244 
245 	for_each_btree_key_norestart(trans, bp_iter, BTREE_ID_backpointers,
246 				     *bp_pos, iter_flags, k, ret) {
247 		if (bpos_ge(k.k->p, bp_end_pos))
248 			break;
249 
250 		*bp_pos = k.k->p;
251 		*bp = *bkey_s_c_to_backpointer(k).v;
252 		goto out;
253 	}
254 done:
255 	*bp_pos = SPOS_MAX;
256 out:
257 	bch2_trans_iter_exit(trans, &bp_iter);
258 	bch2_trans_iter_exit(trans, &alloc_iter);
259 	return ret;
260 }
261 
262 static void backpointer_not_found(struct btree_trans *trans,
263 				  struct bpos bp_pos,
264 				  struct bch_backpointer bp,
265 				  struct bkey_s_c k)
266 {
267 	struct bch_fs *c = trans->c;
268 	struct printbuf buf = PRINTBUF;
269 
270 	/*
271 	 * If we're using the btree write buffer, the backpointer we were
272 	 * looking at may have already been deleted - failure to find what it
273 	 * pointed to is not an error:
274 	 */
275 	if (likely(!bch2_backpointers_no_use_write_buffer))
276 		return;
277 
278 	struct bpos bucket;
279 	if (!bp_pos_to_bucket_nodev(c, bp_pos, &bucket))
280 		return;
281 
282 	prt_printf(&buf, "backpointer doesn't match %s it points to:\n  ",
283 		   bp.level ? "btree node" : "extent");
284 	prt_printf(&buf, "bucket: ");
285 	bch2_bpos_to_text(&buf, bucket);
286 	prt_printf(&buf, "\n  ");
287 
288 	prt_printf(&buf, "backpointer pos: ");
289 	bch2_bpos_to_text(&buf, bp_pos);
290 	prt_printf(&buf, "\n  ");
291 
292 	bch2_backpointer_to_text(&buf, &bp);
293 	prt_printf(&buf, "\n  ");
294 	bch2_bkey_val_to_text(&buf, c, k);
295 	if (c->curr_recovery_pass >= BCH_RECOVERY_PASS_check_extents_to_backpointers)
296 		bch_err_ratelimited(c, "%s", buf.buf);
297 	else
298 		bch2_trans_inconsistent(trans, "%s", buf.buf);
299 
300 	printbuf_exit(&buf);
301 }
302 
303 struct bkey_s_c bch2_backpointer_get_key(struct btree_trans *trans,
304 					 struct btree_iter *iter,
305 					 struct bpos bp_pos,
306 					 struct bch_backpointer bp,
307 					 unsigned iter_flags)
308 {
309 	if (likely(!bp.level)) {
310 		struct bch_fs *c = trans->c;
311 
312 		struct bpos bucket;
313 		if (!bp_pos_to_bucket_nodev(c, bp_pos, &bucket))
314 			return bkey_s_c_err(-EIO);
315 
316 		bch2_trans_node_iter_init(trans, iter,
317 					  bp.btree_id,
318 					  bp.pos,
319 					  0, 0,
320 					  iter_flags);
321 		struct bkey_s_c k = bch2_btree_iter_peek_slot(iter);
322 		if (bkey_err(k)) {
323 			bch2_trans_iter_exit(trans, iter);
324 			return k;
325 		}
326 
327 		if (k.k && extent_matches_bp(c, bp.btree_id, bp.level, k, bucket, bp))
328 			return k;
329 
330 		bch2_trans_iter_exit(trans, iter);
331 		backpointer_not_found(trans, bp_pos, bp, k);
332 		return bkey_s_c_null;
333 	} else {
334 		struct btree *b = bch2_backpointer_get_node(trans, iter, bp_pos, bp);
335 
336 		if (IS_ERR_OR_NULL(b)) {
337 			bch2_trans_iter_exit(trans, iter);
338 			return IS_ERR(b) ? bkey_s_c_err(PTR_ERR(b)) : bkey_s_c_null;
339 		}
340 		return bkey_i_to_s_c(&b->key);
341 	}
342 }
343 
344 struct btree *bch2_backpointer_get_node(struct btree_trans *trans,
345 					struct btree_iter *iter,
346 					struct bpos bp_pos,
347 					struct bch_backpointer bp)
348 {
349 	struct bch_fs *c = trans->c;
350 
351 	BUG_ON(!bp.level);
352 
353 	struct bpos bucket;
354 	if (!bp_pos_to_bucket_nodev(c, bp_pos, &bucket))
355 		return ERR_PTR(-EIO);
356 
357 	bch2_trans_node_iter_init(trans, iter,
358 				  bp.btree_id,
359 				  bp.pos,
360 				  0,
361 				  bp.level - 1,
362 				  0);
363 	struct btree *b = bch2_btree_iter_peek_node(iter);
364 	if (IS_ERR_OR_NULL(b))
365 		goto err;
366 
367 	BUG_ON(b->c.level != bp.level - 1);
368 
369 	if (extent_matches_bp(c, bp.btree_id, bp.level,
370 			      bkey_i_to_s_c(&b->key),
371 			      bucket, bp))
372 		return b;
373 
374 	if (btree_node_will_make_reachable(b)) {
375 		b = ERR_PTR(-BCH_ERR_backpointer_to_overwritten_btree_node);
376 	} else {
377 		backpointer_not_found(trans, bp_pos, bp, bkey_i_to_s_c(&b->key));
378 		b = NULL;
379 	}
380 err:
381 	bch2_trans_iter_exit(trans, iter);
382 	return b;
383 }
384 
385 static int bch2_check_btree_backpointer(struct btree_trans *trans, struct btree_iter *bp_iter,
386 					struct bkey_s_c k)
387 {
388 	struct bch_fs *c = trans->c;
389 	struct btree_iter alloc_iter = { NULL };
390 	struct bkey_s_c alloc_k;
391 	struct printbuf buf = PRINTBUF;
392 	int ret = 0;
393 
394 	struct bpos bucket;
395 	if (!bp_pos_to_bucket_nodev_noerror(c, k.k->p, &bucket)) {
396 		if (fsck_err(trans, backpointer_to_missing_device,
397 			     "backpointer for missing device:\n%s",
398 			     (bch2_bkey_val_to_text(&buf, c, k), buf.buf)))
399 			ret = bch2_btree_delete_at(trans, bp_iter, 0);
400 		goto out;
401 	}
402 
403 	alloc_k = bch2_bkey_get_iter(trans, &alloc_iter, BTREE_ID_alloc, bucket, 0);
404 	ret = bkey_err(alloc_k);
405 	if (ret)
406 		goto out;
407 
408 	if (fsck_err_on(alloc_k.k->type != KEY_TYPE_alloc_v4,
409 			trans, backpointer_to_missing_alloc,
410 			"backpointer for nonexistent alloc key: %llu:%llu:0\n%s",
411 			alloc_iter.pos.inode, alloc_iter.pos.offset,
412 			(bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
413 		ret = bch2_btree_delete_at(trans, bp_iter, 0);
414 		goto out;
415 	}
416 out:
417 fsck_err:
418 	bch2_trans_iter_exit(trans, &alloc_iter);
419 	printbuf_exit(&buf);
420 	return ret;
421 }
422 
423 /* verify that every backpointer has a corresponding alloc key */
424 int bch2_check_btree_backpointers(struct bch_fs *c)
425 {
426 	int ret = bch2_trans_run(c,
427 		for_each_btree_key_commit(trans, iter,
428 			BTREE_ID_backpointers, POS_MIN, 0, k,
429 			NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
430 		  bch2_check_btree_backpointer(trans, &iter, k)));
431 	bch_err_fn(c, ret);
432 	return ret;
433 }
434 
435 struct extents_to_bp_state {
436 	struct bpos	bucket_start;
437 	struct bpos	bucket_end;
438 	struct bkey_buf last_flushed;
439 };
440 
441 static int drop_dev_and_update(struct btree_trans *trans, enum btree_id btree,
442 			       struct bkey_s_c extent, unsigned dev)
443 {
444 	struct bkey_i *n = bch2_bkey_make_mut_noupdate(trans, extent);
445 	int ret = PTR_ERR_OR_ZERO(n);
446 	if (ret)
447 		return ret;
448 
449 	bch2_bkey_drop_device(bkey_i_to_s(n), dev);
450 	return bch2_btree_insert_trans(trans, btree, n, 0);
451 }
452 
453 static int check_extent_checksum(struct btree_trans *trans,
454 				 enum btree_id btree, struct bkey_s_c extent,
455 				 enum btree_id o_btree, struct bkey_s_c extent2, unsigned dev)
456 {
457 	struct bch_fs *c = trans->c;
458 	struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(extent);
459 	const union bch_extent_entry *entry;
460 	struct extent_ptr_decoded p;
461 	struct printbuf buf = PRINTBUF;
462 	void *data_buf = NULL;
463 	struct bio *bio = NULL;
464 	size_t bytes;
465 	int ret = 0;
466 
467 	if (bkey_is_btree_ptr(extent.k))
468 		return false;
469 
470 	bkey_for_each_ptr_decode(extent.k, ptrs, p, entry)
471 		if (p.ptr.dev == dev)
472 			goto found;
473 	BUG();
474 found:
475 	if (!p.crc.csum_type)
476 		return false;
477 
478 	bytes = p.crc.compressed_size << 9;
479 
480 	struct bch_dev *ca = bch2_dev_get_ioref(c, dev, READ);
481 	if (!ca)
482 		return false;
483 
484 	data_buf = kvmalloc(bytes, GFP_KERNEL);
485 	if (!data_buf) {
486 		ret = -ENOMEM;
487 		goto err;
488 	}
489 
490 	bio = bio_alloc(ca->disk_sb.bdev, buf_pages(data_buf, bytes), REQ_OP_READ, GFP_KERNEL);
491 	bio->bi_iter.bi_sector = p.ptr.offset;
492 	bch2_bio_map(bio, data_buf, bytes);
493 	ret = submit_bio_wait(bio);
494 	if (ret)
495 		goto err;
496 
497 	prt_str(&buf, "extents pointing to same space, but first extent checksum bad:");
498 	prt_printf(&buf, "\n  %s ", bch2_btree_id_str(btree));
499 	bch2_bkey_val_to_text(&buf, c, extent);
500 	prt_printf(&buf, "\n  %s ", bch2_btree_id_str(o_btree));
501 	bch2_bkey_val_to_text(&buf, c, extent2);
502 
503 	struct nonce nonce = extent_nonce(extent.k->version, p.crc);
504 	struct bch_csum csum = bch2_checksum(c, p.crc.csum_type, nonce, data_buf, bytes);
505 	if (fsck_err_on(bch2_crc_cmp(csum, p.crc.csum),
506 			trans, dup_backpointer_to_bad_csum_extent,
507 			"%s", buf.buf))
508 		ret = drop_dev_and_update(trans, btree, extent, dev) ?: 1;
509 fsck_err:
510 err:
511 	if (bio)
512 		bio_put(bio);
513 	kvfree(data_buf);
514 	percpu_ref_put(&ca->io_ref);
515 	printbuf_exit(&buf);
516 	return ret;
517 }
518 
519 static int check_bp_exists(struct btree_trans *trans,
520 			   struct extents_to_bp_state *s,
521 			   struct bpos bucket,
522 			   struct bch_backpointer bp,
523 			   struct bkey_s_c orig_k)
524 {
525 	struct bch_fs *c = trans->c;
526 	struct btree_iter bp_iter = {};
527 	struct btree_iter other_extent_iter = {};
528 	struct printbuf buf = PRINTBUF;
529 	struct bkey_s_c bp_k;
530 	int ret = 0;
531 
532 	struct bch_dev *ca = bch2_dev_bucket_tryget(c, bucket);
533 	if (!ca) {
534 		prt_str(&buf, "extent for nonexistent device:bucket ");
535 		bch2_bpos_to_text(&buf, bucket);
536 		prt_str(&buf, "\n  ");
537 		bch2_bkey_val_to_text(&buf, c, orig_k);
538 		bch_err(c, "%s", buf.buf);
539 		ret = -BCH_ERR_fsck_repair_unimplemented;
540 		goto err;
541 	}
542 
543 	if (bpos_lt(bucket, s->bucket_start) ||
544 	    bpos_gt(bucket, s->bucket_end))
545 		goto out;
546 
547 	bp_k = bch2_bkey_get_iter(trans, &bp_iter, BTREE_ID_backpointers,
548 				  bucket_pos_to_bp(ca, bucket, bp.bucket_offset),
549 				  0);
550 	ret = bkey_err(bp_k);
551 	if (ret)
552 		goto err;
553 
554 	if (bp_k.k->type != KEY_TYPE_backpointer ||
555 	    memcmp(bkey_s_c_to_backpointer(bp_k).v, &bp, sizeof(bp))) {
556 		ret = bch2_btree_write_buffer_maybe_flush(trans, orig_k, &s->last_flushed);
557 		if (ret)
558 			goto err;
559 
560 		goto check_existing_bp;
561 	}
562 out:
563 err:
564 fsck_err:
565 	bch2_trans_iter_exit(trans, &other_extent_iter);
566 	bch2_trans_iter_exit(trans, &bp_iter);
567 	bch2_dev_put(ca);
568 	printbuf_exit(&buf);
569 	return ret;
570 check_existing_bp:
571 	/* Do we have a backpointer for a different extent? */
572 	if (bp_k.k->type != KEY_TYPE_backpointer)
573 		goto missing;
574 
575 	struct bch_backpointer other_bp = *bkey_s_c_to_backpointer(bp_k).v;
576 
577 	struct bkey_s_c other_extent =
578 		bch2_backpointer_get_key(trans, &other_extent_iter, bp_k.k->p, other_bp, 0);
579 	ret = bkey_err(other_extent);
580 	if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node)
581 		ret = 0;
582 	if (ret)
583 		goto err;
584 
585 	if (!other_extent.k)
586 		goto missing;
587 
588 	if (bch2_extents_match(orig_k, other_extent)) {
589 		printbuf_reset(&buf);
590 		prt_printf(&buf, "duplicate versions of same extent, deleting smaller\n  ");
591 		bch2_bkey_val_to_text(&buf, c, orig_k);
592 		prt_str(&buf, "\n  ");
593 		bch2_bkey_val_to_text(&buf, c, other_extent);
594 		bch_err(c, "%s", buf.buf);
595 
596 		if (other_extent.k->size <= orig_k.k->size) {
597 			ret = drop_dev_and_update(trans, other_bp.btree_id, other_extent, bucket.inode);
598 			if (ret)
599 				goto err;
600 			goto out;
601 		} else {
602 			ret = drop_dev_and_update(trans, bp.btree_id, orig_k, bucket.inode);
603 			if (ret)
604 				goto err;
605 			goto missing;
606 		}
607 	}
608 
609 	ret = check_extent_checksum(trans, other_bp.btree_id, other_extent, bp.btree_id, orig_k, bucket.inode);
610 	if (ret < 0)
611 		goto err;
612 	if (ret) {
613 		ret = 0;
614 		goto missing;
615 	}
616 
617 	ret = check_extent_checksum(trans, bp.btree_id, orig_k, other_bp.btree_id, other_extent, bucket.inode);
618 	if (ret < 0)
619 		goto err;
620 	if (ret) {
621 		ret = 0;
622 		goto out;
623 	}
624 
625 	printbuf_reset(&buf);
626 	prt_printf(&buf, "duplicate extents pointing to same space on dev %llu\n  ", bucket.inode);
627 	bch2_bkey_val_to_text(&buf, c, orig_k);
628 	prt_str(&buf, "\n  ");
629 	bch2_bkey_val_to_text(&buf, c, other_extent);
630 	bch_err(c, "%s", buf.buf);
631 	ret = -BCH_ERR_fsck_repair_unimplemented;
632 	goto err;
633 missing:
634 	printbuf_reset(&buf);
635 	prt_printf(&buf, "missing backpointer for btree=%s l=%u ",
636 	       bch2_btree_id_str(bp.btree_id), bp.level);
637 	bch2_bkey_val_to_text(&buf, c, orig_k);
638 	prt_printf(&buf, "\n  got:   ");
639 	bch2_bkey_val_to_text(&buf, c, bp_k);
640 
641 	struct bkey_i_backpointer n_bp_k;
642 	bkey_backpointer_init(&n_bp_k.k_i);
643 	n_bp_k.k.p = bucket_pos_to_bp(ca, bucket, bp.bucket_offset);
644 	n_bp_k.v = bp;
645 	prt_printf(&buf, "\n  want:  ");
646 	bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&n_bp_k.k_i));
647 
648 	if (fsck_err(trans, ptr_to_missing_backpointer, "%s", buf.buf))
649 		ret = bch2_bucket_backpointer_mod(trans, ca, bucket, bp, orig_k, true);
650 
651 	goto out;
652 }
653 
654 static int check_extent_to_backpointers(struct btree_trans *trans,
655 					struct extents_to_bp_state *s,
656 					enum btree_id btree, unsigned level,
657 					struct bkey_s_c k)
658 {
659 	struct bch_fs *c = trans->c;
660 	struct bkey_ptrs_c ptrs;
661 	const union bch_extent_entry *entry;
662 	struct extent_ptr_decoded p;
663 	int ret;
664 
665 	ptrs = bch2_bkey_ptrs_c(k);
666 	bkey_for_each_ptr_decode(k.k, ptrs, p, entry) {
667 		struct bpos bucket_pos = POS_MIN;
668 		struct bch_backpointer bp;
669 
670 		if (p.ptr.cached)
671 			continue;
672 
673 		rcu_read_lock();
674 		struct bch_dev *ca = bch2_dev_rcu(c, p.ptr.dev);
675 		if (ca)
676 			bch2_extent_ptr_to_bp(c, ca, btree, level, k, p, entry, &bucket_pos, &bp);
677 		rcu_read_unlock();
678 
679 		if (!ca)
680 			continue;
681 
682 		ret = check_bp_exists(trans, s, bucket_pos, bp, k);
683 		if (ret)
684 			return ret;
685 	}
686 
687 	return 0;
688 }
689 
690 static int check_btree_root_to_backpointers(struct btree_trans *trans,
691 					    struct extents_to_bp_state *s,
692 					    enum btree_id btree_id,
693 					    int *level)
694 {
695 	struct bch_fs *c = trans->c;
696 	struct btree_iter iter;
697 	struct btree *b;
698 	struct bkey_s_c k;
699 	int ret;
700 retry:
701 	bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN,
702 				  0, bch2_btree_id_root(c, btree_id)->b->c.level, 0);
703 	b = bch2_btree_iter_peek_node(&iter);
704 	ret = PTR_ERR_OR_ZERO(b);
705 	if (ret)
706 		goto err;
707 
708 	if (b != btree_node_root(c, b)) {
709 		bch2_trans_iter_exit(trans, &iter);
710 		goto retry;
711 	}
712 
713 	*level = b->c.level;
714 
715 	k = bkey_i_to_s_c(&b->key);
716 	ret = check_extent_to_backpointers(trans, s, btree_id, b->c.level + 1, k);
717 err:
718 	bch2_trans_iter_exit(trans, &iter);
719 	return ret;
720 }
721 
722 static inline struct bbpos bp_to_bbpos(struct bch_backpointer bp)
723 {
724 	return (struct bbpos) {
725 		.btree	= bp.btree_id,
726 		.pos	= bp.pos,
727 	};
728 }
729 
730 static u64 mem_may_pin_bytes(struct bch_fs *c)
731 {
732 	struct sysinfo i;
733 	si_meminfo(&i);
734 
735 	u64 mem_bytes = i.totalram * i.mem_unit;
736 	return div_u64(mem_bytes * c->opts.fsck_memory_usage_percent, 100);
737 }
738 
739 static size_t btree_nodes_fit_in_ram(struct bch_fs *c)
740 {
741 	return div_u64(mem_may_pin_bytes(c), c->opts.btree_node_size);
742 }
743 
744 static int bch2_get_btree_in_memory_pos(struct btree_trans *trans,
745 					u64 btree_leaf_mask,
746 					u64 btree_interior_mask,
747 					struct bbpos start, struct bbpos *end)
748 {
749 	struct bch_fs *c = trans->c;
750 	s64 mem_may_pin = mem_may_pin_bytes(c);
751 	int ret = 0;
752 
753 	btree_interior_mask |= btree_leaf_mask;
754 
755 	c->btree_cache.pinned_nodes_leaf_mask		= btree_leaf_mask;
756 	c->btree_cache.pinned_nodes_interior_mask	= btree_interior_mask;
757 	c->btree_cache.pinned_nodes_start		= start;
758 	c->btree_cache.pinned_nodes_end			= *end = BBPOS_MAX;
759 
760 	for (enum btree_id btree = start.btree;
761 	     btree < BTREE_ID_NR && !ret;
762 	     btree++) {
763 		unsigned depth = (BIT_ULL(btree) & btree_leaf_mask) ? 0 : 1;
764 
765 		if (!(BIT_ULL(btree) & btree_leaf_mask) &&
766 		    !(BIT_ULL(btree) & btree_interior_mask))
767 			continue;
768 
769 		ret = __for_each_btree_node(trans, iter, btree,
770 				      btree == start.btree ? start.pos : POS_MIN,
771 				      0, depth, BTREE_ITER_prefetch, b, ({
772 			mem_may_pin -= btree_buf_bytes(b);
773 			if (mem_may_pin <= 0) {
774 				c->btree_cache.pinned_nodes_end = *end =
775 					BBPOS(btree, b->key.k.p);
776 				break;
777 			}
778 			0;
779 		}));
780 	}
781 
782 	return ret;
783 }
784 
785 static int bch2_check_extents_to_backpointers_pass(struct btree_trans *trans,
786 						   struct extents_to_bp_state *s)
787 {
788 	struct bch_fs *c = trans->c;
789 	int ret = 0;
790 
791 	for (enum btree_id btree_id = 0;
792 	     btree_id < btree_id_nr_alive(c);
793 	     btree_id++) {
794 		int level, depth = btree_type_has_ptrs(btree_id) ? 0 : 1;
795 
796 		ret = commit_do(trans, NULL, NULL,
797 				BCH_TRANS_COMMIT_no_enospc,
798 				check_btree_root_to_backpointers(trans, s, btree_id, &level));
799 		if (ret)
800 			return ret;
801 
802 		while (level >= depth) {
803 			struct btree_iter iter;
804 			bch2_trans_node_iter_init(trans, &iter, btree_id, POS_MIN, 0, level,
805 						  BTREE_ITER_prefetch);
806 
807 			ret = for_each_btree_key_continue(trans, iter, 0, k, ({
808 				check_extent_to_backpointers(trans, s, btree_id, level, k) ?:
809 				bch2_trans_commit(trans, NULL, NULL, BCH_TRANS_COMMIT_no_enospc);
810 			}));
811 			if (ret)
812 				return ret;
813 
814 			--level;
815 		}
816 	}
817 
818 	return 0;
819 }
820 
821 int bch2_check_extents_to_backpointers(struct bch_fs *c)
822 {
823 	struct btree_trans *trans = bch2_trans_get(c);
824 	struct extents_to_bp_state s = { .bucket_start = POS_MIN };
825 	int ret;
826 
827 	bch2_bkey_buf_init(&s.last_flushed);
828 	bkey_init(&s.last_flushed.k->k);
829 
830 	while (1) {
831 		struct bbpos end;
832 		ret = bch2_get_btree_in_memory_pos(trans,
833 				BIT_ULL(BTREE_ID_backpointers),
834 				BIT_ULL(BTREE_ID_backpointers),
835 				BBPOS(BTREE_ID_backpointers, s.bucket_start), &end);
836 		if (ret)
837 			break;
838 
839 		s.bucket_end = end.pos;
840 
841 		if ( bpos_eq(s.bucket_start, POS_MIN) &&
842 		    !bpos_eq(s.bucket_end, SPOS_MAX))
843 			bch_verbose(c, "%s(): alloc info does not fit in ram, running in multiple passes with %zu nodes per pass",
844 				    __func__, btree_nodes_fit_in_ram(c));
845 
846 		if (!bpos_eq(s.bucket_start, POS_MIN) ||
847 		    !bpos_eq(s.bucket_end, SPOS_MAX)) {
848 			struct printbuf buf = PRINTBUF;
849 
850 			prt_str(&buf, "check_extents_to_backpointers(): ");
851 			bch2_bpos_to_text(&buf, s.bucket_start);
852 			prt_str(&buf, "-");
853 			bch2_bpos_to_text(&buf, s.bucket_end);
854 
855 			bch_verbose(c, "%s", buf.buf);
856 			printbuf_exit(&buf);
857 		}
858 
859 		ret = bch2_check_extents_to_backpointers_pass(trans, &s);
860 		if (ret || bpos_eq(s.bucket_end, SPOS_MAX))
861 			break;
862 
863 		s.bucket_start = bpos_successor(s.bucket_end);
864 	}
865 	bch2_trans_put(trans);
866 	bch2_bkey_buf_exit(&s.last_flushed, c);
867 
868 	c->btree_cache.pinned_nodes_leaf_mask = 0;
869 	c->btree_cache.pinned_nodes_interior_mask = 0;
870 
871 	bch_err_fn(c, ret);
872 	return ret;
873 }
874 
875 static int check_one_backpointer(struct btree_trans *trans,
876 				 struct bbpos start,
877 				 struct bbpos end,
878 				 struct bkey_s_c_backpointer bp,
879 				 struct bkey_buf *last_flushed)
880 {
881 	struct bch_fs *c = trans->c;
882 	struct btree_iter iter;
883 	struct bbpos pos = bp_to_bbpos(*bp.v);
884 	struct bkey_s_c k;
885 	struct printbuf buf = PRINTBUF;
886 	int ret;
887 
888 	if (bbpos_cmp(pos, start) < 0 ||
889 	    bbpos_cmp(pos, end) > 0)
890 		return 0;
891 
892 	k = bch2_backpointer_get_key(trans, &iter, bp.k->p, *bp.v, 0);
893 	ret = bkey_err(k);
894 	if (ret == -BCH_ERR_backpointer_to_overwritten_btree_node)
895 		return 0;
896 	if (ret)
897 		return ret;
898 
899 	if (!k.k) {
900 		ret = bch2_btree_write_buffer_maybe_flush(trans, bp.s_c, last_flushed);
901 		if (ret)
902 			goto out;
903 
904 		if (fsck_err(trans, backpointer_to_missing_ptr,
905 			     "backpointer for missing %s\n  %s",
906 			     bp.v->level ? "btree node" : "extent",
907 			     (bch2_bkey_val_to_text(&buf, c, bp.s_c), buf.buf))) {
908 			ret = bch2_btree_delete_at_buffered(trans, BTREE_ID_backpointers, bp.k->p);
909 			goto out;
910 		}
911 	}
912 out:
913 fsck_err:
914 	bch2_trans_iter_exit(trans, &iter);
915 	printbuf_exit(&buf);
916 	return ret;
917 }
918 
919 static int bch2_check_backpointers_to_extents_pass(struct btree_trans *trans,
920 						   struct bbpos start,
921 						   struct bbpos end)
922 {
923 	struct bkey_buf last_flushed;
924 
925 	bch2_bkey_buf_init(&last_flushed);
926 	bkey_init(&last_flushed.k->k);
927 
928 	int ret = for_each_btree_key_commit(trans, iter, BTREE_ID_backpointers,
929 				  POS_MIN, BTREE_ITER_prefetch, k,
930 				  NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
931 		check_one_backpointer(trans, start, end,
932 				      bkey_s_c_to_backpointer(k),
933 				      &last_flushed));
934 
935 	bch2_bkey_buf_exit(&last_flushed, trans->c);
936 	return ret;
937 }
938 
939 int bch2_check_backpointers_to_extents(struct bch_fs *c)
940 {
941 	struct btree_trans *trans = bch2_trans_get(c);
942 	struct bbpos start = (struct bbpos) { .btree = 0, .pos = POS_MIN, }, end;
943 	int ret;
944 
945 	while (1) {
946 		ret = bch2_get_btree_in_memory_pos(trans,
947 						   BIT_ULL(BTREE_ID_extents)|
948 						   BIT_ULL(BTREE_ID_reflink),
949 						   ~0,
950 						   start, &end);
951 		if (ret)
952 			break;
953 
954 		if (!bbpos_cmp(start, BBPOS_MIN) &&
955 		    bbpos_cmp(end, BBPOS_MAX))
956 			bch_verbose(c, "%s(): extents do not fit in ram, running in multiple passes with %zu nodes per pass",
957 				    __func__, btree_nodes_fit_in_ram(c));
958 
959 		if (bbpos_cmp(start, BBPOS_MIN) ||
960 		    bbpos_cmp(end, BBPOS_MAX)) {
961 			struct printbuf buf = PRINTBUF;
962 
963 			prt_str(&buf, "check_backpointers_to_extents(): ");
964 			bch2_bbpos_to_text(&buf, start);
965 			prt_str(&buf, "-");
966 			bch2_bbpos_to_text(&buf, end);
967 
968 			bch_verbose(c, "%s", buf.buf);
969 			printbuf_exit(&buf);
970 		}
971 
972 		ret = bch2_check_backpointers_to_extents_pass(trans, start, end);
973 		if (ret || !bbpos_cmp(end, BBPOS_MAX))
974 			break;
975 
976 		start = bbpos_successor(end);
977 	}
978 	bch2_trans_put(trans);
979 
980 	c->btree_cache.pinned_nodes_leaf_mask = 0;
981 	c->btree_cache.pinned_nodes_interior_mask = 0;
982 
983 	bch_err_fn(c, ret);
984 	return ret;
985 }
986