interconnect: qcom: icc-rpm: Fix peak rate calculation
[linux-2.6-microblaze.git] / fs / bcachefs / fsck.c
1 // SPDX-License-Identifier: GPL-2.0
2
3 #include "bcachefs.h"
4 #include "bkey_buf.h"
5 #include "btree_cache.h"
6 #include "btree_update.h"
7 #include "buckets.h"
8 #include "darray.h"
9 #include "dirent.h"
10 #include "error.h"
11 #include "fs-common.h"
12 #include "fsck.h"
13 #include "inode.h"
14 #include "keylist.h"
15 #include "recovery.h"
16 #include "snapshot.h"
17 #include "super.h"
18 #include "xattr.h"
19
20 #include <linux/bsearch.h>
21 #include <linux/dcache.h> /* struct qstr */
22
23 #define QSTR(n) { { { .len = strlen(n) } }, .name = n }
24
25 /*
26  * XXX: this is handling transaction restarts without returning
27  * -BCH_ERR_transaction_restart_nested, this is not how we do things anymore:
28  */
29 static s64 bch2_count_inode_sectors(struct btree_trans *trans, u64 inum,
30                                     u32 snapshot)
31 {
32         struct btree_iter iter;
33         struct bkey_s_c k;
34         u64 sectors = 0;
35         int ret;
36
37         for_each_btree_key_upto(trans, iter, BTREE_ID_extents,
38                                 SPOS(inum, 0, snapshot),
39                                 POS(inum, U64_MAX),
40                                 0, k, ret)
41                 if (bkey_extent_is_allocation(k.k))
42                         sectors += k.k->size;
43
44         bch2_trans_iter_exit(trans, &iter);
45
46         return ret ?: sectors;
47 }
48
49 static s64 bch2_count_subdirs(struct btree_trans *trans, u64 inum,
50                                     u32 snapshot)
51 {
52         struct btree_iter iter;
53         struct bkey_s_c k;
54         struct bkey_s_c_dirent d;
55         u64 subdirs = 0;
56         int ret;
57
58         for_each_btree_key_upto(trans, iter, BTREE_ID_dirents,
59                                 SPOS(inum, 0, snapshot),
60                                 POS(inum, U64_MAX),
61                                 0, k, ret) {
62                 if (k.k->type != KEY_TYPE_dirent)
63                         continue;
64
65                 d = bkey_s_c_to_dirent(k);
66                 if (d.v->d_type == DT_DIR)
67                         subdirs++;
68         }
69         bch2_trans_iter_exit(trans, &iter);
70
71         return ret ?: subdirs;
72 }
73
74 static int __snapshot_lookup_subvol(struct btree_trans *trans, u32 snapshot,
75                                     u32 *subvol)
76 {
77         struct bch_snapshot s;
78         int ret = bch2_bkey_get_val_typed(trans, BTREE_ID_snapshots,
79                                           POS(0, snapshot), 0,
80                                           snapshot, &s);
81         if (!ret)
82                 *subvol = le32_to_cpu(s.subvol);
83         else if (bch2_err_matches(ret, ENOENT))
84                 bch_err(trans->c, "snapshot %u not found", snapshot);
85         return ret;
86
87 }
88
89 static int __subvol_lookup(struct btree_trans *trans, u32 subvol,
90                            u32 *snapshot, u64 *inum)
91 {
92         struct bch_subvolume s;
93         int ret;
94
95         ret = bch2_subvolume_get(trans, subvol, false, 0, &s);
96
97         *snapshot = le32_to_cpu(s.snapshot);
98         *inum = le64_to_cpu(s.inode);
99         return ret;
100 }
101
102 static int subvol_lookup(struct btree_trans *trans, u32 subvol,
103                          u32 *snapshot, u64 *inum)
104 {
105         return lockrestart_do(trans, __subvol_lookup(trans, subvol, snapshot, inum));
106 }
107
108 static int lookup_first_inode(struct btree_trans *trans, u64 inode_nr,
109                               struct bch_inode_unpacked *inode)
110 {
111         struct btree_iter iter;
112         struct bkey_s_c k;
113         int ret;
114
115         bch2_trans_iter_init(trans, &iter, BTREE_ID_inodes,
116                              POS(0, inode_nr),
117                              BTREE_ITER_ALL_SNAPSHOTS);
118         k = bch2_btree_iter_peek(&iter);
119         ret = bkey_err(k);
120         if (ret)
121                 goto err;
122
123         if (!k.k || !bkey_eq(k.k->p, POS(0, inode_nr))) {
124                 ret = -BCH_ERR_ENOENT_inode;
125                 goto err;
126         }
127
128         ret = bch2_inode_unpack(k, inode);
129 err:
130         bch_err_msg(trans->c, ret, "fetching inode %llu", inode_nr);
131         bch2_trans_iter_exit(trans, &iter);
132         return ret;
133 }
134
135 static int __lookup_inode(struct btree_trans *trans, u64 inode_nr,
136                           struct bch_inode_unpacked *inode,
137                           u32 *snapshot)
138 {
139         struct btree_iter iter;
140         struct bkey_s_c k;
141         int ret;
142
143         k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_inodes,
144                                SPOS(0, inode_nr, *snapshot), 0);
145         ret = bkey_err(k);
146         if (ret)
147                 goto err;
148
149         ret = bkey_is_inode(k.k)
150                 ? bch2_inode_unpack(k, inode)
151                 : -BCH_ERR_ENOENT_inode;
152         if (!ret)
153                 *snapshot = iter.pos.snapshot;
154 err:
155         bch_err_msg(trans->c, ret, "fetching inode %llu:%u", inode_nr, *snapshot);
156         bch2_trans_iter_exit(trans, &iter);
157         return ret;
158 }
159
160 static int lookup_inode(struct btree_trans *trans, u64 inode_nr,
161                         struct bch_inode_unpacked *inode,
162                         u32 *snapshot)
163 {
164         return lockrestart_do(trans, __lookup_inode(trans, inode_nr, inode, snapshot));
165 }
166
167 static int __lookup_dirent(struct btree_trans *trans,
168                            struct bch_hash_info hash_info,
169                            subvol_inum dir, struct qstr *name,
170                            u64 *target, unsigned *type)
171 {
172         struct btree_iter iter;
173         struct bkey_s_c_dirent d;
174         int ret;
175
176         ret = bch2_hash_lookup(trans, &iter, bch2_dirent_hash_desc,
177                                &hash_info, dir, name, 0);
178         if (ret)
179                 return ret;
180
181         d = bkey_s_c_to_dirent(bch2_btree_iter_peek_slot(&iter));
182         *target = le64_to_cpu(d.v->d_inum);
183         *type = d.v->d_type;
184         bch2_trans_iter_exit(trans, &iter);
185         return 0;
186 }
187
188 static int __write_inode(struct btree_trans *trans,
189                          struct bch_inode_unpacked *inode,
190                          u32 snapshot)
191 {
192         struct bkey_inode_buf *inode_p =
193                 bch2_trans_kmalloc(trans, sizeof(*inode_p));
194
195         if (IS_ERR(inode_p))
196                 return PTR_ERR(inode_p);
197
198         bch2_inode_pack(inode_p, inode);
199         inode_p->inode.k.p.snapshot = snapshot;
200
201         return bch2_btree_insert_nonextent(trans, BTREE_ID_inodes,
202                                 &inode_p->inode.k_i,
203                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
204 }
205
206 static int fsck_write_inode(struct btree_trans *trans,
207                             struct bch_inode_unpacked *inode,
208                             u32 snapshot)
209 {
210         int ret = commit_do(trans, NULL, NULL,
211                                   BTREE_INSERT_NOFAIL|
212                                   BTREE_INSERT_LAZY_RW,
213                                   __write_inode(trans, inode, snapshot));
214         if (ret)
215                 bch_err_fn(trans->c, ret);
216         return ret;
217 }
218
219 static int __remove_dirent(struct btree_trans *trans, struct bpos pos)
220 {
221         struct bch_fs *c = trans->c;
222         struct btree_iter iter;
223         struct bch_inode_unpacked dir_inode;
224         struct bch_hash_info dir_hash_info;
225         int ret;
226
227         ret = lookup_first_inode(trans, pos.inode, &dir_inode);
228         if (ret)
229                 goto err;
230
231         dir_hash_info = bch2_hash_info_init(c, &dir_inode);
232
233         bch2_trans_iter_init(trans, &iter, BTREE_ID_dirents, pos, BTREE_ITER_INTENT);
234
235         ret = bch2_hash_delete_at(trans, bch2_dirent_hash_desc,
236                                   &dir_hash_info, &iter,
237                                   BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
238         bch2_trans_iter_exit(trans, &iter);
239 err:
240         bch_err_fn(c, ret);
241         return ret;
242 }
243
244 /* Get lost+found, create if it doesn't exist: */
245 static int lookup_lostfound(struct btree_trans *trans, u32 subvol,
246                             struct bch_inode_unpacked *lostfound)
247 {
248         struct bch_fs *c = trans->c;
249         struct bch_inode_unpacked root;
250         struct bch_hash_info root_hash_info;
251         struct qstr lostfound_str = QSTR("lost+found");
252         subvol_inum root_inum = { .subvol = subvol };
253         u64 inum = 0;
254         unsigned d_type = 0;
255         u32 snapshot;
256         int ret;
257
258         ret = __subvol_lookup(trans, subvol, &snapshot, &root_inum.inum);
259         if (ret)
260                 return ret;
261
262         ret = __lookup_inode(trans, root_inum.inum, &root, &snapshot);
263         if (ret)
264                 return ret;
265
266         root_hash_info = bch2_hash_info_init(c, &root);
267
268         ret = __lookup_dirent(trans, root_hash_info, root_inum,
269                             &lostfound_str, &inum, &d_type);
270         if (bch2_err_matches(ret, ENOENT)) {
271                 bch_notice(c, "creating lost+found");
272                 goto create_lostfound;
273         }
274
275         bch_err_fn(c, ret);
276         if (ret)
277                 return ret;
278
279         if (d_type != DT_DIR) {
280                 bch_err(c, "error looking up lost+found: not a directory");
281                 return -BCH_ERR_ENOENT_not_directory;
282         }
283
284         /*
285          * The bch2_check_dirents pass has already run, dangling dirents
286          * shouldn't exist here:
287          */
288         return __lookup_inode(trans, inum, lostfound, &snapshot);
289
290 create_lostfound:
291         bch2_inode_init_early(c, lostfound);
292
293         ret = bch2_create_trans(trans, root_inum, &root,
294                                 lostfound, &lostfound_str,
295                                 0, 0, S_IFDIR|0700, 0, NULL, NULL,
296                                 (subvol_inum) { }, 0);
297         bch_err_msg(c, ret, "creating lost+found");
298         return ret;
299 }
300
301 static int __reattach_inode(struct btree_trans *trans,
302                           struct bch_inode_unpacked *inode,
303                           u32 inode_snapshot)
304 {
305         struct bch_hash_info dir_hash;
306         struct bch_inode_unpacked lostfound;
307         char name_buf[20];
308         struct qstr name;
309         u64 dir_offset = 0;
310         u32 subvol;
311         int ret;
312
313         ret = __snapshot_lookup_subvol(trans, inode_snapshot, &subvol);
314         if (ret)
315                 return ret;
316
317         ret = lookup_lostfound(trans, subvol, &lostfound);
318         if (ret)
319                 return ret;
320
321         if (S_ISDIR(inode->bi_mode)) {
322                 lostfound.bi_nlink++;
323
324                 ret = __write_inode(trans, &lostfound, U32_MAX);
325                 if (ret)
326                         return ret;
327         }
328
329         dir_hash = bch2_hash_info_init(trans->c, &lostfound);
330
331         snprintf(name_buf, sizeof(name_buf), "%llu", inode->bi_inum);
332         name = (struct qstr) QSTR(name_buf);
333
334         ret = bch2_dirent_create(trans,
335                                  (subvol_inum) {
336                                         .subvol = subvol,
337                                         .inum = lostfound.bi_inum,
338                                  },
339                                  &dir_hash,
340                                  inode_d_type(inode),
341                                  &name, inode->bi_inum, &dir_offset,
342                                  BCH_HASH_SET_MUST_CREATE);
343         if (ret)
344                 return ret;
345
346         inode->bi_dir           = lostfound.bi_inum;
347         inode->bi_dir_offset    = dir_offset;
348
349         return __write_inode(trans, inode, inode_snapshot);
350 }
351
352 static int reattach_inode(struct btree_trans *trans,
353                           struct bch_inode_unpacked *inode,
354                           u32 inode_snapshot)
355 {
356         int ret = commit_do(trans, NULL, NULL,
357                                   BTREE_INSERT_LAZY_RW|
358                                   BTREE_INSERT_NOFAIL,
359                         __reattach_inode(trans, inode, inode_snapshot));
360         bch_err_msg(trans->c, ret, "reattaching inode %llu", inode->bi_inum);
361         return ret;
362 }
363
364 static int remove_backpointer(struct btree_trans *trans,
365                               struct bch_inode_unpacked *inode)
366 {
367         struct btree_iter iter;
368         struct bkey_s_c_dirent d;
369         int ret;
370
371         d = bch2_bkey_get_iter_typed(trans, &iter, BTREE_ID_dirents,
372                                      POS(inode->bi_dir, inode->bi_dir_offset), 0,
373                                      dirent);
374         ret =   bkey_err(d) ?:
375                 __remove_dirent(trans, d.k->p);
376         bch2_trans_iter_exit(trans, &iter);
377         return ret;
378 }
379
380 struct snapshots_seen_entry {
381         u32                             id;
382         u32                             equiv;
383 };
384
385 struct snapshots_seen {
386         struct bpos                     pos;
387         DARRAY(struct snapshots_seen_entry) ids;
388 };
389
390 static inline void snapshots_seen_exit(struct snapshots_seen *s)
391 {
392         darray_exit(&s->ids);
393 }
394
395 static inline void snapshots_seen_init(struct snapshots_seen *s)
396 {
397         memset(s, 0, sizeof(*s));
398 }
399
400 static int snapshots_seen_add_inorder(struct bch_fs *c, struct snapshots_seen *s, u32 id)
401 {
402         struct snapshots_seen_entry *i, n = {
403                 .id     = id,
404                 .equiv  = bch2_snapshot_equiv(c, id),
405         };
406         int ret = 0;
407
408         darray_for_each(s->ids, i) {
409                 if (i->id == id)
410                         return 0;
411                 if (i->id > id)
412                         break;
413         }
414
415         ret = darray_insert_item(&s->ids, i - s->ids.data, n);
416         if (ret)
417                 bch_err(c, "error reallocating snapshots_seen table (size %zu)",
418                         s->ids.size);
419         return ret;
420 }
421
422 static int snapshots_seen_update(struct bch_fs *c, struct snapshots_seen *s,
423                                  enum btree_id btree_id, struct bpos pos)
424 {
425         struct snapshots_seen_entry *i, n = {
426                 .id     = pos.snapshot,
427                 .equiv  = bch2_snapshot_equiv(c, pos.snapshot),
428         };
429         int ret = 0;
430
431         if (!bkey_eq(s->pos, pos))
432                 s->ids.nr = 0;
433
434         s->pos = pos;
435         s->pos.snapshot = n.equiv;
436
437         darray_for_each(s->ids, i) {
438                 if (i->id == n.id)
439                         return 0;
440
441                 /*
442                  * We currently don't rigorously track for snapshot cleanup
443                  * needing to be run, so it shouldn't be a fsck error yet:
444                  */
445                 if (i->equiv == n.equiv) {
446                         bch_err(c, "snapshot deletion did not finish:\n"
447                                 "  duplicate keys in btree %s at %llu:%llu snapshots %u, %u (equiv %u)\n",
448                                 bch2_btree_id_str(btree_id),
449                                 pos.inode, pos.offset,
450                                 i->id, n.id, n.equiv);
451                         set_bit(BCH_FS_NEED_DELETE_DEAD_SNAPSHOTS, &c->flags);
452                         return bch2_run_explicit_recovery_pass(c, BCH_RECOVERY_PASS_delete_dead_snapshots);
453                 }
454         }
455
456         ret = darray_push(&s->ids, n);
457         if (ret)
458                 bch_err(c, "error reallocating snapshots_seen table (size %zu)",
459                         s->ids.size);
460         return ret;
461 }
462
463 /**
464  * key_visible_in_snapshot - returns true if @id is a descendent of @ancestor,
465  * and @ancestor hasn't been overwritten in @seen
466  *
467  * @c:          filesystem handle
468  * @seen:       list of snapshot ids already seen at current position
469  * @id:         descendent snapshot id
470  * @ancestor:   ancestor snapshot id
471  *
472  * Returns:     whether key in @ancestor snapshot is visible in @id snapshot
473  */
474 static bool key_visible_in_snapshot(struct bch_fs *c, struct snapshots_seen *seen,
475                                     u32 id, u32 ancestor)
476 {
477         ssize_t i;
478
479         EBUG_ON(id > ancestor);
480         EBUG_ON(!bch2_snapshot_is_equiv(c, id));
481         EBUG_ON(!bch2_snapshot_is_equiv(c, ancestor));
482
483         /* @ancestor should be the snapshot most recently added to @seen */
484         EBUG_ON(ancestor != seen->pos.snapshot);
485         EBUG_ON(ancestor != seen->ids.data[seen->ids.nr - 1].equiv);
486
487         if (id == ancestor)
488                 return true;
489
490         if (!bch2_snapshot_is_ancestor(c, id, ancestor))
491                 return false;
492
493         /*
494          * We know that @id is a descendant of @ancestor, we're checking if
495          * we've seen a key that overwrote @ancestor - i.e. also a descendent of
496          * @ascestor and with @id as a descendent.
497          *
498          * But we already know that we're scanning IDs between @id and @ancestor
499          * numerically, since snapshot ID lists are kept sorted, so if we find
500          * an id that's an ancestor of @id we're done:
501          */
502
503         for (i = seen->ids.nr - 2;
504              i >= 0 && seen->ids.data[i].equiv >= id;
505              --i)
506                 if (bch2_snapshot_is_ancestor(c, id, seen->ids.data[i].equiv))
507                         return false;
508
509         return true;
510 }
511
512 /**
513  * ref_visible - given a key with snapshot id @src that points to a key with
514  * snapshot id @dst, test whether there is some snapshot in which @dst is
515  * visible.
516  *
517  * @c:          filesystem handle
518  * @s:          list of snapshot IDs already seen at @src
519  * @src:        snapshot ID of src key
520  * @dst:        snapshot ID of dst key
521  * Returns:     true if there is some snapshot in which @dst is visible
522  *
523  * Assumes we're visiting @src keys in natural key order
524  */
525 static bool ref_visible(struct bch_fs *c, struct snapshots_seen *s,
526                         u32 src, u32 dst)
527 {
528         return dst <= src
529                 ? key_visible_in_snapshot(c, s, dst, src)
530                 : bch2_snapshot_is_ancestor(c, src, dst);
531 }
532
533 static int ref_visible2(struct bch_fs *c,
534                         u32 src, struct snapshots_seen *src_seen,
535                         u32 dst, struct snapshots_seen *dst_seen)
536 {
537         src = bch2_snapshot_equiv(c, src);
538         dst = bch2_snapshot_equiv(c, dst);
539
540         if (dst > src) {
541                 swap(dst, src);
542                 swap(dst_seen, src_seen);
543         }
544         return key_visible_in_snapshot(c, src_seen, dst, src);
545 }
546
547 #define for_each_visible_inode(_c, _s, _w, _snapshot, _i)                               \
548         for (_i = (_w)->inodes.data; _i < (_w)->inodes.data + (_w)->inodes.nr &&        \
549              (_i)->snapshot <= (_snapshot); _i++)                                       \
550                 if (key_visible_in_snapshot(_c, _s, _i->snapshot, _snapshot))
551
552 struct inode_walker_entry {
553         struct bch_inode_unpacked inode;
554         u32                     snapshot;
555         bool                    seen_this_pos;
556         u64                     count;
557 };
558
559 struct inode_walker {
560         bool                            first_this_inode;
561         bool                            recalculate_sums;
562         struct bpos                     last_pos;
563
564         DARRAY(struct inode_walker_entry) inodes;
565 };
566
567 static void inode_walker_exit(struct inode_walker *w)
568 {
569         darray_exit(&w->inodes);
570 }
571
572 static struct inode_walker inode_walker_init(void)
573 {
574         return (struct inode_walker) { 0, };
575 }
576
577 static int add_inode(struct bch_fs *c, struct inode_walker *w,
578                      struct bkey_s_c inode)
579 {
580         struct bch_inode_unpacked u;
581
582         BUG_ON(bch2_inode_unpack(inode, &u));
583
584         return darray_push(&w->inodes, ((struct inode_walker_entry) {
585                 .inode          = u,
586                 .snapshot       = bch2_snapshot_equiv(c, inode.k->p.snapshot),
587         }));
588 }
589
590 static int get_inodes_all_snapshots(struct btree_trans *trans,
591                                     struct inode_walker *w, u64 inum)
592 {
593         struct bch_fs *c = trans->c;
594         struct btree_iter iter;
595         struct bkey_s_c k;
596         u32 restart_count = trans->restart_count;
597         int ret;
598
599         w->recalculate_sums = false;
600         w->inodes.nr = 0;
601
602         for_each_btree_key(trans, iter, BTREE_ID_inodes, POS(0, inum),
603                            BTREE_ITER_ALL_SNAPSHOTS, k, ret) {
604                 if (k.k->p.offset != inum)
605                         break;
606
607                 if (bkey_is_inode(k.k))
608                         add_inode(c, w, k);
609         }
610         bch2_trans_iter_exit(trans, &iter);
611
612         if (ret)
613                 return ret;
614
615         w->first_this_inode = true;
616
617         return trans_was_restarted(trans, restart_count);
618 }
619
620 static struct inode_walker_entry *
621 lookup_inode_for_snapshot(struct bch_fs *c, struct inode_walker *w,
622                           u32 snapshot, bool is_whiteout)
623 {
624         struct inode_walker_entry *i;
625
626         snapshot = bch2_snapshot_equiv(c, snapshot);
627
628         darray_for_each(w->inodes, i)
629                 if (bch2_snapshot_is_ancestor(c, snapshot, i->snapshot))
630                         goto found;
631
632         return NULL;
633 found:
634         BUG_ON(snapshot > i->snapshot);
635
636         if (snapshot != i->snapshot && !is_whiteout) {
637                 struct inode_walker_entry new = *i;
638                 size_t pos;
639                 int ret;
640
641                 new.snapshot = snapshot;
642                 new.count = 0;
643
644                 bch_info(c, "have key for inode %llu:%u but have inode in ancestor snapshot %u",
645                          w->last_pos.inode, snapshot, i->snapshot);
646
647                 while (i > w->inodes.data && i[-1].snapshot > snapshot)
648                         --i;
649
650                 pos = i - w->inodes.data;
651                 ret = darray_insert_item(&w->inodes, pos, new);
652                 if (ret)
653                         return ERR_PTR(ret);
654
655                 i = w->inodes.data + pos;
656         }
657
658         return i;
659 }
660
661 static struct inode_walker_entry *walk_inode(struct btree_trans *trans,
662                                              struct inode_walker *w, struct bpos pos,
663                                              bool is_whiteout)
664 {
665         if (w->last_pos.inode != pos.inode) {
666                 int ret = get_inodes_all_snapshots(trans, w, pos.inode);
667                 if (ret)
668                         return ERR_PTR(ret);
669         } else if (bkey_cmp(w->last_pos, pos)) {
670                 struct inode_walker_entry *i;
671
672                 darray_for_each(w->inodes, i)
673                         i->seen_this_pos = false;
674
675         }
676
677         w->last_pos = pos;
678
679         return lookup_inode_for_snapshot(trans->c, w, pos.snapshot, is_whiteout);
680 }
681
682 static int __get_visible_inodes(struct btree_trans *trans,
683                                 struct inode_walker *w,
684                                 struct snapshots_seen *s,
685                                 u64 inum)
686 {
687         struct bch_fs *c = trans->c;
688         struct btree_iter iter;
689         struct bkey_s_c k;
690         int ret;
691
692         w->inodes.nr = 0;
693
694         for_each_btree_key_norestart(trans, iter, BTREE_ID_inodes, POS(0, inum),
695                            BTREE_ITER_ALL_SNAPSHOTS, k, ret) {
696                 u32 equiv = bch2_snapshot_equiv(c, k.k->p.snapshot);
697
698                 if (k.k->p.offset != inum)
699                         break;
700
701                 if (!ref_visible(c, s, s->pos.snapshot, equiv))
702                         continue;
703
704                 if (bkey_is_inode(k.k))
705                         add_inode(c, w, k);
706
707                 if (equiv >= s->pos.snapshot)
708                         break;
709         }
710         bch2_trans_iter_exit(trans, &iter);
711
712         return ret;
713 }
714
715 static int check_key_has_snapshot(struct btree_trans *trans,
716                                   struct btree_iter *iter,
717                                   struct bkey_s_c k)
718 {
719         struct bch_fs *c = trans->c;
720         struct printbuf buf = PRINTBUF;
721         int ret = 0;
722
723         if (mustfix_fsck_err_on(!bch2_snapshot_equiv(c, k.k->p.snapshot), c,
724                                 bkey_in_missing_snapshot,
725                                 "key in missing snapshot: %s",
726                                 (bch2_bkey_val_to_text(&buf, c, k), buf.buf)))
727                 ret = bch2_btree_delete_at(trans, iter,
728                                             BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?: 1;
729 fsck_err:
730         printbuf_exit(&buf);
731         return ret;
732 }
733
734 static int hash_redo_key(struct btree_trans *trans,
735                          const struct bch_hash_desc desc,
736                          struct bch_hash_info *hash_info,
737                          struct btree_iter *k_iter, struct bkey_s_c k)
738 {
739         struct bkey_i *delete;
740         struct bkey_i *tmp;
741
742         delete = bch2_trans_kmalloc(trans, sizeof(*delete));
743         if (IS_ERR(delete))
744                 return PTR_ERR(delete);
745
746         tmp = bch2_bkey_make_mut_noupdate(trans, k);
747         if (IS_ERR(tmp))
748                 return PTR_ERR(tmp);
749
750         bkey_init(&delete->k);
751         delete->k.p = k_iter->pos;
752         return  bch2_btree_iter_traverse(k_iter) ?:
753                 bch2_trans_update(trans, k_iter, delete, 0) ?:
754                 bch2_hash_set_snapshot(trans, desc, hash_info,
755                                        (subvol_inum) { 0, k.k->p.inode },
756                                        k.k->p.snapshot, tmp,
757                                        BCH_HASH_SET_MUST_CREATE,
758                                        BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE) ?:
759                 bch2_trans_commit(trans, NULL, NULL,
760                                   BTREE_INSERT_NOFAIL|
761                                   BTREE_INSERT_LAZY_RW);
762 }
763
764 static int hash_check_key(struct btree_trans *trans,
765                           const struct bch_hash_desc desc,
766                           struct bch_hash_info *hash_info,
767                           struct btree_iter *k_iter, struct bkey_s_c hash_k)
768 {
769         struct bch_fs *c = trans->c;
770         struct btree_iter iter = { NULL };
771         struct printbuf buf = PRINTBUF;
772         struct bkey_s_c k;
773         u64 hash;
774         int ret = 0;
775
776         if (hash_k.k->type != desc.key_type)
777                 return 0;
778
779         hash = desc.hash_bkey(hash_info, hash_k);
780
781         if (likely(hash == hash_k.k->p.offset))
782                 return 0;
783
784         if (hash_k.k->p.offset < hash)
785                 goto bad_hash;
786
787         for_each_btree_key_norestart(trans, iter, desc.btree_id,
788                                      SPOS(hash_k.k->p.inode, hash, hash_k.k->p.snapshot),
789                                      BTREE_ITER_SLOTS, k, ret) {
790                 if (bkey_eq(k.k->p, hash_k.k->p))
791                         break;
792
793                 if (fsck_err_on(k.k->type == desc.key_type &&
794                                 !desc.cmp_bkey(k, hash_k), c,
795                                 hash_table_key_duplicate,
796                                 "duplicate hash table keys:\n%s",
797                                 (printbuf_reset(&buf),
798                                  bch2_bkey_val_to_text(&buf, c, hash_k),
799                                  buf.buf))) {
800                         ret = bch2_hash_delete_at(trans, desc, hash_info, k_iter, 0) ?: 1;
801                         break;
802                 }
803
804                 if (bkey_deleted(k.k)) {
805                         bch2_trans_iter_exit(trans, &iter);
806                         goto bad_hash;
807                 }
808         }
809 out:
810         bch2_trans_iter_exit(trans, &iter);
811         printbuf_exit(&buf);
812         return ret;
813 bad_hash:
814         if (fsck_err(c, hash_table_key_wrong_offset,
815                      "hash table key at wrong offset: btree %s inode %llu offset %llu, hashed to %llu\n%s",
816                      bch2_btree_id_str(desc.btree_id), hash_k.k->p.inode, hash_k.k->p.offset, hash,
817                      (printbuf_reset(&buf),
818                       bch2_bkey_val_to_text(&buf, c, hash_k), buf.buf))) {
819                 ret = hash_redo_key(trans, desc, hash_info, k_iter, hash_k);
820                 bch_err_fn(c, ret);
821                 if (ret)
822                         return ret;
823                 ret = -BCH_ERR_transaction_restart_nested;
824         }
825 fsck_err:
826         goto out;
827 }
828
829 static int check_inode(struct btree_trans *trans,
830                        struct btree_iter *iter,
831                        struct bkey_s_c k,
832                        struct bch_inode_unpacked *prev,
833                        struct snapshots_seen *s,
834                        bool full)
835 {
836         struct bch_fs *c = trans->c;
837         struct bch_inode_unpacked u;
838         bool do_update = false;
839         int ret;
840
841         ret = check_key_has_snapshot(trans, iter, k);
842         if (ret < 0)
843                 goto err;
844         if (ret)
845                 return 0;
846
847         ret = snapshots_seen_update(c, s, iter->btree_id, k.k->p);
848         if (ret)
849                 goto err;
850
851         if (!bkey_is_inode(k.k))
852                 return 0;
853
854         BUG_ON(bch2_inode_unpack(k, &u));
855
856         if (!full &&
857             !(u.bi_flags & (BCH_INODE_i_size_dirty|
858                             BCH_INODE_i_sectors_dirty|
859                             BCH_INODE_unlinked)))
860                 return 0;
861
862         if (prev->bi_inum != u.bi_inum)
863                 *prev = u;
864
865         if (fsck_err_on(prev->bi_hash_seed      != u.bi_hash_seed ||
866                         inode_d_type(prev)      != inode_d_type(&u),
867                         c, inode_snapshot_mismatch,
868                         "inodes in different snapshots don't match")) {
869                 bch_err(c, "repair not implemented yet");
870                 return -EINVAL;
871         }
872
873         if ((u.bi_flags & (BCH_INODE_i_size_dirty|BCH_INODE_unlinked)) &&
874             bch2_key_has_snapshot_overwrites(trans, BTREE_ID_inodes, k.k->p)) {
875                 struct bpos new_min_pos;
876
877                 ret = bch2_propagate_key_to_snapshot_leaves(trans, iter->btree_id, k, &new_min_pos);
878                 if (ret)
879                         goto err;
880
881                 u.bi_flags &= ~BCH_INODE_i_size_dirty|BCH_INODE_unlinked;
882
883                 ret = __write_inode(trans, &u, iter->pos.snapshot);
884                 bch_err_msg(c, ret, "in fsck updating inode");
885                 if (ret)
886                         return ret;
887
888                 if (!bpos_eq(new_min_pos, POS_MIN))
889                         bch2_btree_iter_set_pos(iter, bpos_predecessor(new_min_pos));
890                 return 0;
891         }
892
893         if (u.bi_flags & BCH_INODE_unlinked &&
894             (!c->sb.clean ||
895              fsck_err(c, inode_unlinked_but_clean,
896                       "filesystem marked clean, but inode %llu unlinked",
897                       u.bi_inum))) {
898                 bch2_trans_unlock(trans);
899                 bch2_fs_lazy_rw(c);
900
901                 ret = bch2_inode_rm_snapshot(trans, u.bi_inum, iter->pos.snapshot);
902                 bch_err_msg(c, ret, "in fsck deleting inode");
903                 return ret;
904         }
905
906         if (u.bi_flags & BCH_INODE_i_size_dirty &&
907             (!c->sb.clean ||
908              fsck_err(c, inode_i_size_dirty_but_clean,
909                       "filesystem marked clean, but inode %llu has i_size dirty",
910                       u.bi_inum))) {
911                 bch_verbose(c, "truncating inode %llu", u.bi_inum);
912
913                 bch2_trans_unlock(trans);
914                 bch2_fs_lazy_rw(c);
915
916                 /*
917                  * XXX: need to truncate partial blocks too here - or ideally
918                  * just switch units to bytes and that issue goes away
919                  */
920                 ret = bch2_btree_delete_range_trans(trans, BTREE_ID_extents,
921                                 SPOS(u.bi_inum, round_up(u.bi_size, block_bytes(c)) >> 9,
922                                      iter->pos.snapshot),
923                                 POS(u.bi_inum, U64_MAX),
924                                 0, NULL);
925                 bch_err_msg(c, ret, "in fsck truncating inode");
926                 if (ret)
927                         return ret;
928
929                 /*
930                  * We truncated without our normal sector accounting hook, just
931                  * make sure we recalculate it:
932                  */
933                 u.bi_flags |= BCH_INODE_i_sectors_dirty;
934
935                 u.bi_flags &= ~BCH_INODE_i_size_dirty;
936                 do_update = true;
937         }
938
939         if (u.bi_flags & BCH_INODE_i_sectors_dirty &&
940             (!c->sb.clean ||
941              fsck_err(c, inode_i_sectors_dirty_but_clean,
942                       "filesystem marked clean, but inode %llu has i_sectors dirty",
943                       u.bi_inum))) {
944                 s64 sectors;
945
946                 bch_verbose(c, "recounting sectors for inode %llu",
947                             u.bi_inum);
948
949                 sectors = bch2_count_inode_sectors(trans, u.bi_inum, iter->pos.snapshot);
950                 if (sectors < 0) {
951                         bch_err_msg(c, sectors, "in fsck recounting inode sectors");
952                         return sectors;
953                 }
954
955                 u.bi_sectors = sectors;
956                 u.bi_flags &= ~BCH_INODE_i_sectors_dirty;
957                 do_update = true;
958         }
959
960         if (u.bi_flags & BCH_INODE_backptr_untrusted) {
961                 u.bi_dir = 0;
962                 u.bi_dir_offset = 0;
963                 u.bi_flags &= ~BCH_INODE_backptr_untrusted;
964                 do_update = true;
965         }
966
967         if (do_update) {
968                 ret = __write_inode(trans, &u, iter->pos.snapshot);
969                 bch_err_msg(c, ret, "in fsck updating inode");
970                 if (ret)
971                         return ret;
972         }
973 err:
974 fsck_err:
975         bch_err_fn(c, ret);
976         return ret;
977 }
978
979 noinline_for_stack
980 int bch2_check_inodes(struct bch_fs *c)
981 {
982         bool full = c->opts.fsck;
983         struct btree_trans *trans = bch2_trans_get(c);
984         struct btree_iter iter;
985         struct bch_inode_unpacked prev = { 0 };
986         struct snapshots_seen s;
987         struct bkey_s_c k;
988         int ret;
989
990         snapshots_seen_init(&s);
991
992         ret = for_each_btree_key_commit(trans, iter, BTREE_ID_inodes,
993                         POS_MIN,
994                         BTREE_ITER_PREFETCH|BTREE_ITER_ALL_SNAPSHOTS, k,
995                         NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
996                 check_inode(trans, &iter, k, &prev, &s, full));
997
998         snapshots_seen_exit(&s);
999         bch2_trans_put(trans);
1000         bch_err_fn(c, ret);
1001         return ret;
1002 }
1003
1004 static struct bkey_s_c_dirent dirent_get_by_pos(struct btree_trans *trans,
1005                                                 struct btree_iter *iter,
1006                                                 struct bpos pos)
1007 {
1008         return bch2_bkey_get_iter_typed(trans, iter, BTREE_ID_dirents, pos, 0, dirent);
1009 }
1010
1011 static bool inode_points_to_dirent(struct bch_inode_unpacked *inode,
1012                                    struct bkey_s_c_dirent d)
1013 {
1014         return  inode->bi_dir           == d.k->p.inode &&
1015                 inode->bi_dir_offset    == d.k->p.offset;
1016 }
1017
1018 static bool dirent_points_to_inode(struct bkey_s_c_dirent d,
1019                                    struct bch_inode_unpacked *inode)
1020 {
1021         return d.v->d_type == DT_SUBVOL
1022                 ? le32_to_cpu(d.v->d_child_subvol)      == inode->bi_subvol
1023                 : le64_to_cpu(d.v->d_inum)              == inode->bi_inum;
1024 }
1025
1026 static int inode_backpointer_exists(struct btree_trans *trans,
1027                                     struct bch_inode_unpacked *inode,
1028                                     u32 snapshot)
1029 {
1030         struct btree_iter iter;
1031         struct bkey_s_c_dirent d;
1032         int ret;
1033
1034         d = dirent_get_by_pos(trans, &iter,
1035                         SPOS(inode->bi_dir, inode->bi_dir_offset, snapshot));
1036         ret = bkey_err(d);
1037         if (ret)
1038                 return bch2_err_matches(ret, ENOENT) ? 0 : ret;
1039
1040         ret = dirent_points_to_inode(d, inode);
1041         bch2_trans_iter_exit(trans, &iter);
1042         return ret;
1043 }
1044
1045 static int check_i_sectors(struct btree_trans *trans, struct inode_walker *w)
1046 {
1047         struct bch_fs *c = trans->c;
1048         struct inode_walker_entry *i;
1049         u32 restart_count = trans->restart_count;
1050         int ret = 0;
1051         s64 count2;
1052
1053         darray_for_each(w->inodes, i) {
1054                 if (i->inode.bi_sectors == i->count)
1055                         continue;
1056
1057                 count2 = bch2_count_inode_sectors(trans, w->last_pos.inode, i->snapshot);
1058
1059                 if (w->recalculate_sums)
1060                         i->count = count2;
1061
1062                 if (i->count != count2) {
1063                         bch_err(c, "fsck counted i_sectors wrong for inode %llu:%u: got %llu should be %llu",
1064                                 w->last_pos.inode, i->snapshot, i->count, count2);
1065                         return -BCH_ERR_internal_fsck_err;
1066                 }
1067
1068                 if (fsck_err_on(!(i->inode.bi_flags & BCH_INODE_i_sectors_dirty),
1069                                 c, inode_i_sectors_wrong,
1070                                 "inode %llu:%u has incorrect i_sectors: got %llu, should be %llu",
1071                                 w->last_pos.inode, i->snapshot,
1072                                 i->inode.bi_sectors, i->count)) {
1073                         i->inode.bi_sectors = i->count;
1074                         ret = fsck_write_inode(trans, &i->inode, i->snapshot);
1075                         if (ret)
1076                                 break;
1077                 }
1078         }
1079 fsck_err:
1080         bch_err_fn(c, ret);
1081         return ret ?: trans_was_restarted(trans, restart_count);
1082 }
1083
1084 struct extent_end {
1085         u32                     snapshot;
1086         u64                     offset;
1087         struct snapshots_seen   seen;
1088 };
1089
1090 struct extent_ends {
1091         struct bpos                     last_pos;
1092         DARRAY(struct extent_end)       e;
1093 };
1094
1095 static void extent_ends_reset(struct extent_ends *extent_ends)
1096 {
1097         struct extent_end *i;
1098
1099         darray_for_each(extent_ends->e, i)
1100                 snapshots_seen_exit(&i->seen);
1101
1102         extent_ends->e.nr = 0;
1103 }
1104
1105 static void extent_ends_exit(struct extent_ends *extent_ends)
1106 {
1107         extent_ends_reset(extent_ends);
1108         darray_exit(&extent_ends->e);
1109 }
1110
1111 static void extent_ends_init(struct extent_ends *extent_ends)
1112 {
1113         memset(extent_ends, 0, sizeof(*extent_ends));
1114 }
1115
1116 static int extent_ends_at(struct bch_fs *c,
1117                           struct extent_ends *extent_ends,
1118                           struct snapshots_seen *seen,
1119                           struct bkey_s_c k)
1120 {
1121         struct extent_end *i, n = (struct extent_end) {
1122                 .offset         = k.k->p.offset,
1123                 .snapshot       = k.k->p.snapshot,
1124                 .seen           = *seen,
1125         };
1126
1127         n.seen.ids.data = kmemdup(seen->ids.data,
1128                               sizeof(seen->ids.data[0]) * seen->ids.size,
1129                               GFP_KERNEL);
1130         if (!n.seen.ids.data)
1131                 return -BCH_ERR_ENOMEM_fsck_extent_ends_at;
1132
1133         darray_for_each(extent_ends->e, i) {
1134                 if (i->snapshot == k.k->p.snapshot) {
1135                         snapshots_seen_exit(&i->seen);
1136                         *i = n;
1137                         return 0;
1138                 }
1139
1140                 if (i->snapshot >= k.k->p.snapshot)
1141                         break;
1142         }
1143
1144         return darray_insert_item(&extent_ends->e, i - extent_ends->e.data, n);
1145 }
1146
1147 static int overlapping_extents_found(struct btree_trans *trans,
1148                                      enum btree_id btree,
1149                                      struct bpos pos1, struct snapshots_seen *pos1_seen,
1150                                      struct bkey pos2,
1151                                      bool *fixed,
1152                                      struct extent_end *extent_end)
1153 {
1154         struct bch_fs *c = trans->c;
1155         struct printbuf buf = PRINTBUF;
1156         struct btree_iter iter1, iter2 = { NULL };
1157         struct bkey_s_c k1, k2;
1158         int ret;
1159
1160         BUG_ON(bkey_le(pos1, bkey_start_pos(&pos2)));
1161
1162         bch2_trans_iter_init(trans, &iter1, btree, pos1,
1163                              BTREE_ITER_ALL_SNAPSHOTS|
1164                              BTREE_ITER_NOT_EXTENTS);
1165         k1 = bch2_btree_iter_peek_upto(&iter1, POS(pos1.inode, U64_MAX));
1166         ret = bkey_err(k1);
1167         if (ret)
1168                 goto err;
1169
1170         prt_str(&buf, "\n  ");
1171         bch2_bkey_val_to_text(&buf, c, k1);
1172
1173         if (!bpos_eq(pos1, k1.k->p)) {
1174                 prt_str(&buf, "\n  wanted\n  ");
1175                 bch2_bpos_to_text(&buf, pos1);
1176                 prt_str(&buf, "\n  ");
1177                 bch2_bkey_to_text(&buf, &pos2);
1178
1179                 bch_err(c, "%s: error finding first overlapping extent when repairing, got%s",
1180                         __func__, buf.buf);
1181                 ret = -BCH_ERR_internal_fsck_err;
1182                 goto err;
1183         }
1184
1185         bch2_trans_copy_iter(&iter2, &iter1);
1186
1187         while (1) {
1188                 bch2_btree_iter_advance(&iter2);
1189
1190                 k2 = bch2_btree_iter_peek_upto(&iter2, POS(pos1.inode, U64_MAX));
1191                 ret = bkey_err(k2);
1192                 if (ret)
1193                         goto err;
1194
1195                 if (bpos_ge(k2.k->p, pos2.p))
1196                         break;
1197         }
1198
1199         prt_str(&buf, "\n  ");
1200         bch2_bkey_val_to_text(&buf, c, k2);
1201
1202         if (bpos_gt(k2.k->p, pos2.p) ||
1203             pos2.size != k2.k->size) {
1204                 bch_err(c, "%s: error finding seconding overlapping extent when repairing%s",
1205                         __func__, buf.buf);
1206                 ret = -BCH_ERR_internal_fsck_err;
1207                 goto err;
1208         }
1209
1210         prt_printf(&buf, "\n  overwriting %s extent",
1211                    pos1.snapshot >= pos2.p.snapshot ? "first" : "second");
1212
1213         if (fsck_err(c, extent_overlapping,
1214                      "overlapping extents%s", buf.buf)) {
1215                 struct btree_iter *old_iter = &iter1;
1216                 struct disk_reservation res = { 0 };
1217
1218                 if (pos1.snapshot < pos2.p.snapshot) {
1219                         old_iter = &iter2;
1220                         swap(k1, k2);
1221                 }
1222
1223                 trans->extra_journal_res += bch2_bkey_sectors_compressed(k2);
1224
1225                 ret =   bch2_trans_update_extent_overwrite(trans, old_iter,
1226                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE,
1227                                 k1, k2) ?:
1228                         bch2_trans_commit(trans, &res, NULL,
1229                                 BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL);
1230                 bch2_disk_reservation_put(c, &res);
1231
1232                 if (ret)
1233                         goto err;
1234
1235                 *fixed = true;
1236
1237                 if (pos1.snapshot == pos2.p.snapshot) {
1238                         /*
1239                          * We overwrote the first extent, and did the overwrite
1240                          * in the same snapshot:
1241                          */
1242                         extent_end->offset = bkey_start_offset(&pos2);
1243                 } else if (pos1.snapshot > pos2.p.snapshot) {
1244                         /*
1245                          * We overwrote the first extent in pos2's snapshot:
1246                          */
1247                         ret = snapshots_seen_add_inorder(c, pos1_seen, pos2.p.snapshot);
1248                 } else {
1249                         /*
1250                          * We overwrote the second extent - restart
1251                          * check_extent() from the top:
1252                          */
1253                         ret = -BCH_ERR_transaction_restart_nested;
1254                 }
1255         }
1256 fsck_err:
1257 err:
1258         bch2_trans_iter_exit(trans, &iter2);
1259         bch2_trans_iter_exit(trans, &iter1);
1260         printbuf_exit(&buf);
1261         return ret;
1262 }
1263
1264 static int check_overlapping_extents(struct btree_trans *trans,
1265                               struct snapshots_seen *seen,
1266                               struct extent_ends *extent_ends,
1267                               struct bkey_s_c k,
1268                               u32 equiv,
1269                               struct btree_iter *iter,
1270                               bool *fixed)
1271 {
1272         struct bch_fs *c = trans->c;
1273         struct extent_end *i;
1274         int ret = 0;
1275
1276         /* transaction restart, running again */
1277         if (bpos_eq(extent_ends->last_pos, k.k->p))
1278                 return 0;
1279
1280         if (extent_ends->last_pos.inode != k.k->p.inode)
1281                 extent_ends_reset(extent_ends);
1282
1283         darray_for_each(extent_ends->e, i) {
1284                 if (i->offset <= bkey_start_offset(k.k))
1285                         continue;
1286
1287                 if (!ref_visible2(c,
1288                                   k.k->p.snapshot, seen,
1289                                   i->snapshot, &i->seen))
1290                         continue;
1291
1292                 ret = overlapping_extents_found(trans, iter->btree_id,
1293                                                 SPOS(iter->pos.inode,
1294                                                      i->offset,
1295                                                      i->snapshot),
1296                                                 &i->seen,
1297                                                 *k.k, fixed, i);
1298                 if (ret)
1299                         goto err;
1300         }
1301
1302         ret = extent_ends_at(c, extent_ends, seen, k);
1303         if (ret)
1304                 goto err;
1305
1306         extent_ends->last_pos = k.k->p;
1307 err:
1308         return ret;
1309 }
1310
1311 static int check_extent_overbig(struct btree_trans *trans, struct btree_iter *iter,
1312                                 struct bkey_s_c k)
1313 {
1314         struct bch_fs *c = trans->c;
1315         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k);
1316         struct bch_extent_crc_unpacked crc;
1317         const union bch_extent_entry *i;
1318         unsigned encoded_extent_max_sectors = c->opts.encoded_extent_max >> 9;
1319
1320         bkey_for_each_crc(k.k, ptrs, crc, i)
1321                 if (crc_is_encoded(crc) &&
1322                     crc.uncompressed_size > encoded_extent_max_sectors) {
1323                         struct printbuf buf = PRINTBUF;
1324
1325                         bch2_bkey_val_to_text(&buf, c, k);
1326                         bch_err(c, "overbig encoded extent, please report this:\n  %s", buf.buf);
1327                         printbuf_exit(&buf);
1328                 }
1329
1330         return 0;
1331 }
1332
1333 static int check_extent(struct btree_trans *trans, struct btree_iter *iter,
1334                         struct bkey_s_c k,
1335                         struct inode_walker *inode,
1336                         struct snapshots_seen *s,
1337                         struct extent_ends *extent_ends)
1338 {
1339         struct bch_fs *c = trans->c;
1340         struct inode_walker_entry *i;
1341         struct printbuf buf = PRINTBUF;
1342         struct bpos equiv = k.k->p;
1343         int ret = 0;
1344
1345         equiv.snapshot = bch2_snapshot_equiv(c, k.k->p.snapshot);
1346
1347         ret = check_key_has_snapshot(trans, iter, k);
1348         if (ret) {
1349                 ret = ret < 0 ? ret : 0;
1350                 goto out;
1351         }
1352
1353         if (inode->last_pos.inode != k.k->p.inode) {
1354                 ret = check_i_sectors(trans, inode);
1355                 if (ret)
1356                         goto err;
1357         }
1358
1359         i = walk_inode(trans, inode, equiv, k.k->type == KEY_TYPE_whiteout);
1360         ret = PTR_ERR_OR_ZERO(i);
1361         if (ret)
1362                 goto err;
1363
1364         ret = snapshots_seen_update(c, s, iter->btree_id, k.k->p);
1365         if (ret)
1366                 goto err;
1367
1368         if (k.k->type != KEY_TYPE_whiteout) {
1369                 if (fsck_err_on(!i, c, extent_in_missing_inode,
1370                                 "extent in missing inode:\n  %s",
1371                                 (printbuf_reset(&buf),
1372                                  bch2_bkey_val_to_text(&buf, c, k), buf.buf)))
1373                         goto delete;
1374
1375                 if (fsck_err_on(i &&
1376                                 !S_ISREG(i->inode.bi_mode) &&
1377                                 !S_ISLNK(i->inode.bi_mode),
1378                                 c, extent_in_non_reg_inode,
1379                                 "extent in non regular inode mode %o:\n  %s",
1380                                 i->inode.bi_mode,
1381                                 (printbuf_reset(&buf),
1382                                  bch2_bkey_val_to_text(&buf, c, k), buf.buf)))
1383                         goto delete;
1384
1385                 ret = check_overlapping_extents(trans, s, extent_ends, k,
1386                                                 equiv.snapshot, iter,
1387                                                 &inode->recalculate_sums);
1388                 if (ret)
1389                         goto err;
1390         }
1391
1392         /*
1393          * Check inodes in reverse order, from oldest snapshots to newest,
1394          * starting from the inode that matches this extent's snapshot. If we
1395          * didn't have one, iterate over all inodes:
1396          */
1397         if (!i)
1398                 i = inode->inodes.data + inode->inodes.nr - 1;
1399
1400         for (;
1401              inode->inodes.data && i >= inode->inodes.data;
1402              --i) {
1403                 if (i->snapshot > equiv.snapshot ||
1404                     !key_visible_in_snapshot(c, s, i->snapshot, equiv.snapshot))
1405                         continue;
1406
1407                 if (k.k->type != KEY_TYPE_whiteout) {
1408                         if (fsck_err_on(!(i->inode.bi_flags & BCH_INODE_i_size_dirty) &&
1409                                         k.k->p.offset > round_up(i->inode.bi_size, block_bytes(c)) >> 9 &&
1410                                         !bkey_extent_is_reservation(k),
1411                                         c, extent_past_end_of_inode,
1412                                         "extent type past end of inode %llu:%u, i_size %llu\n  %s",
1413                                         i->inode.bi_inum, i->snapshot, i->inode.bi_size,
1414                                         (bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
1415                                 struct btree_iter iter2;
1416
1417                                 bch2_trans_copy_iter(&iter2, iter);
1418                                 bch2_btree_iter_set_snapshot(&iter2, i->snapshot);
1419                                 ret =   bch2_btree_iter_traverse(&iter2) ?:
1420                                         bch2_btree_delete_at(trans, &iter2,
1421                                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
1422                                 bch2_trans_iter_exit(trans, &iter2);
1423                                 if (ret)
1424                                         goto err;
1425
1426                                 iter->k.type = KEY_TYPE_whiteout;
1427                         }
1428
1429                         if (bkey_extent_is_allocation(k.k))
1430                                 i->count += k.k->size;
1431                 }
1432
1433                 i->seen_this_pos = true;
1434         }
1435 out:
1436 err:
1437 fsck_err:
1438         printbuf_exit(&buf);
1439         bch_err_fn(c, ret);
1440         return ret;
1441 delete:
1442         ret = bch2_btree_delete_at(trans, iter, BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
1443         goto out;
1444 }
1445
1446 /*
1447  * Walk extents: verify that extents have a corresponding S_ISREG inode, and
1448  * that i_size an i_sectors are consistent
1449  */
1450 int bch2_check_extents(struct bch_fs *c)
1451 {
1452         struct inode_walker w = inode_walker_init();
1453         struct snapshots_seen s;
1454         struct btree_trans *trans = bch2_trans_get(c);
1455         struct btree_iter iter;
1456         struct bkey_s_c k;
1457         struct extent_ends extent_ends;
1458         struct disk_reservation res = { 0 };
1459         int ret = 0;
1460
1461         snapshots_seen_init(&s);
1462         extent_ends_init(&extent_ends);
1463
1464         ret = for_each_btree_key_commit(trans, iter, BTREE_ID_extents,
1465                         POS(BCACHEFS_ROOT_INO, 0),
1466                         BTREE_ITER_PREFETCH|BTREE_ITER_ALL_SNAPSHOTS, k,
1467                         &res, NULL,
1468                         BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL, ({
1469                 bch2_disk_reservation_put(c, &res);
1470                 check_extent(trans, &iter, k, &w, &s, &extent_ends) ?:
1471                 check_extent_overbig(trans, &iter, k);
1472         })) ?:
1473         check_i_sectors(trans, &w);
1474
1475         bch2_disk_reservation_put(c, &res);
1476         extent_ends_exit(&extent_ends);
1477         inode_walker_exit(&w);
1478         snapshots_seen_exit(&s);
1479         bch2_trans_put(trans);
1480
1481         bch_err_fn(c, ret);
1482         return ret;
1483 }
1484
1485 int bch2_check_indirect_extents(struct bch_fs *c)
1486 {
1487         struct btree_trans *trans = bch2_trans_get(c);
1488         struct btree_iter iter;
1489         struct bkey_s_c k;
1490         struct disk_reservation res = { 0 };
1491         int ret = 0;
1492
1493         ret = for_each_btree_key_commit(trans, iter, BTREE_ID_reflink,
1494                         POS_MIN,
1495                         BTREE_ITER_PREFETCH, k,
1496                         &res, NULL,
1497                         BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL, ({
1498                 bch2_disk_reservation_put(c, &res);
1499                 check_extent_overbig(trans, &iter, k);
1500         }));
1501
1502         bch2_disk_reservation_put(c, &res);
1503         bch2_trans_put(trans);
1504
1505         bch_err_fn(c, ret);
1506         return ret;
1507 }
1508
1509 static int check_subdir_count(struct btree_trans *trans, struct inode_walker *w)
1510 {
1511         struct bch_fs *c = trans->c;
1512         struct inode_walker_entry *i;
1513         u32 restart_count = trans->restart_count;
1514         int ret = 0;
1515         s64 count2;
1516
1517         darray_for_each(w->inodes, i) {
1518                 if (i->inode.bi_nlink == i->count)
1519                         continue;
1520
1521                 count2 = bch2_count_subdirs(trans, w->last_pos.inode, i->snapshot);
1522                 if (count2 < 0)
1523                         return count2;
1524
1525                 if (i->count != count2) {
1526                         bch_err(c, "fsck counted subdirectories wrong: got %llu should be %llu",
1527                                 i->count, count2);
1528                         i->count = count2;
1529                         if (i->inode.bi_nlink == i->count)
1530                                 continue;
1531                 }
1532
1533                 if (fsck_err_on(i->inode.bi_nlink != i->count,
1534                                 c, inode_dir_wrong_nlink,
1535                                 "directory %llu:%u with wrong i_nlink: got %u, should be %llu",
1536                                 w->last_pos.inode, i->snapshot, i->inode.bi_nlink, i->count)) {
1537                         i->inode.bi_nlink = i->count;
1538                         ret = fsck_write_inode(trans, &i->inode, i->snapshot);
1539                         if (ret)
1540                                 break;
1541                 }
1542         }
1543 fsck_err:
1544         bch_err_fn(c, ret);
1545         return ret ?: trans_was_restarted(trans, restart_count);
1546 }
1547
1548 static int check_dirent_target(struct btree_trans *trans,
1549                                struct btree_iter *iter,
1550                                struct bkey_s_c_dirent d,
1551                                struct bch_inode_unpacked *target,
1552                                u32 target_snapshot)
1553 {
1554         struct bch_fs *c = trans->c;
1555         struct bkey_i_dirent *n;
1556         bool backpointer_exists = true;
1557         struct printbuf buf = PRINTBUF;
1558         int ret = 0;
1559
1560         if (!target->bi_dir &&
1561             !target->bi_dir_offset) {
1562                 target->bi_dir          = d.k->p.inode;
1563                 target->bi_dir_offset   = d.k->p.offset;
1564
1565                 ret = __write_inode(trans, target, target_snapshot);
1566                 if (ret)
1567                         goto err;
1568         }
1569
1570         if (!inode_points_to_dirent(target, d)) {
1571                 ret = inode_backpointer_exists(trans, target, d.k->p.snapshot);
1572                 if (ret < 0)
1573                         goto err;
1574
1575                 backpointer_exists = ret;
1576                 ret = 0;
1577
1578                 if (fsck_err_on(S_ISDIR(target->bi_mode) && backpointer_exists,
1579                                 c, inode_dir_multiple_links,
1580                                 "directory %llu with multiple links",
1581                                 target->bi_inum)) {
1582                         ret = __remove_dirent(trans, d.k->p);
1583                         goto out;
1584                 }
1585
1586                 if (fsck_err_on(backpointer_exists && !target->bi_nlink,
1587                                 c, inode_multiple_links_but_nlink_0,
1588                                 "inode %llu type %s has multiple links but i_nlink 0",
1589                                 target->bi_inum, bch2_d_types[d.v->d_type])) {
1590                         target->bi_nlink++;
1591                         target->bi_flags &= ~BCH_INODE_unlinked;
1592
1593                         ret = __write_inode(trans, target, target_snapshot);
1594                         if (ret)
1595                                 goto err;
1596                 }
1597
1598                 if (fsck_err_on(!backpointer_exists,
1599                                 c, inode_wrong_backpointer,
1600                                 "inode %llu:%u has wrong backpointer:\n"
1601                                 "got       %llu:%llu\n"
1602                                 "should be %llu:%llu",
1603                                 target->bi_inum, target_snapshot,
1604                                 target->bi_dir,
1605                                 target->bi_dir_offset,
1606                                 d.k->p.inode,
1607                                 d.k->p.offset)) {
1608                         target->bi_dir          = d.k->p.inode;
1609                         target->bi_dir_offset   = d.k->p.offset;
1610
1611                         ret = __write_inode(trans, target, target_snapshot);
1612                         if (ret)
1613                                 goto err;
1614                 }
1615         }
1616
1617         if (fsck_err_on(d.v->d_type != inode_d_type(target),
1618                         c, dirent_d_type_wrong,
1619                         "incorrect d_type: got %s, should be %s:\n%s",
1620                         bch2_d_type_str(d.v->d_type),
1621                         bch2_d_type_str(inode_d_type(target)),
1622                         (printbuf_reset(&buf),
1623                          bch2_bkey_val_to_text(&buf, c, d.s_c), buf.buf))) {
1624                 n = bch2_trans_kmalloc(trans, bkey_bytes(d.k));
1625                 ret = PTR_ERR_OR_ZERO(n);
1626                 if (ret)
1627                         goto err;
1628
1629                 bkey_reassemble(&n->k_i, d.s_c);
1630                 n->v.d_type = inode_d_type(target);
1631
1632                 ret = bch2_trans_update(trans, iter, &n->k_i, 0);
1633                 if (ret)
1634                         goto err;
1635
1636                 d = dirent_i_to_s_c(n);
1637         }
1638
1639         if (d.v->d_type == DT_SUBVOL &&
1640             target->bi_parent_subvol != le32_to_cpu(d.v->d_parent_subvol) &&
1641             (c->sb.version < bcachefs_metadata_version_subvol_dirent ||
1642              fsck_err(c, dirent_d_parent_subvol_wrong,
1643                       "dirent has wrong d_parent_subvol field: got %u, should be %u",
1644                       le32_to_cpu(d.v->d_parent_subvol),
1645                       target->bi_parent_subvol))) {
1646                 n = bch2_trans_kmalloc(trans, bkey_bytes(d.k));
1647                 ret = PTR_ERR_OR_ZERO(n);
1648                 if (ret)
1649                         goto err;
1650
1651                 bkey_reassemble(&n->k_i, d.s_c);
1652                 n->v.d_parent_subvol = cpu_to_le32(target->bi_parent_subvol);
1653
1654                 ret = bch2_trans_update(trans, iter, &n->k_i, 0);
1655                 if (ret)
1656                         goto err;
1657
1658                 d = dirent_i_to_s_c(n);
1659         }
1660 out:
1661 err:
1662 fsck_err:
1663         printbuf_exit(&buf);
1664         bch_err_fn(c, ret);
1665         return ret;
1666 }
1667
1668 static int check_dirent(struct btree_trans *trans, struct btree_iter *iter,
1669                         struct bkey_s_c k,
1670                         struct bch_hash_info *hash_info,
1671                         struct inode_walker *dir,
1672                         struct inode_walker *target,
1673                         struct snapshots_seen *s)
1674 {
1675         struct bch_fs *c = trans->c;
1676         struct bkey_s_c_dirent d;
1677         struct inode_walker_entry *i;
1678         struct printbuf buf = PRINTBUF;
1679         struct bpos equiv;
1680         int ret = 0;
1681
1682         ret = check_key_has_snapshot(trans, iter, k);
1683         if (ret) {
1684                 ret = ret < 0 ? ret : 0;
1685                 goto out;
1686         }
1687
1688         equiv = k.k->p;
1689         equiv.snapshot = bch2_snapshot_equiv(c, k.k->p.snapshot);
1690
1691         ret = snapshots_seen_update(c, s, iter->btree_id, k.k->p);
1692         if (ret)
1693                 goto err;
1694
1695         if (k.k->type == KEY_TYPE_whiteout)
1696                 goto out;
1697
1698         if (dir->last_pos.inode != k.k->p.inode) {
1699                 ret = check_subdir_count(trans, dir);
1700                 if (ret)
1701                         goto err;
1702         }
1703
1704         BUG_ON(!iter->path->should_be_locked);
1705
1706         i = walk_inode(trans, dir, equiv, k.k->type == KEY_TYPE_whiteout);
1707         ret = PTR_ERR_OR_ZERO(i);
1708         if (ret < 0)
1709                 goto err;
1710
1711         if (dir->first_this_inode && dir->inodes.nr)
1712                 *hash_info = bch2_hash_info_init(c, &dir->inodes.data[0].inode);
1713         dir->first_this_inode = false;
1714
1715         if (fsck_err_on(!i, c, dirent_in_missing_dir_inode,
1716                         "dirent in nonexisting directory:\n%s",
1717                         (printbuf_reset(&buf),
1718                          bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
1719                 ret = bch2_btree_delete_at(trans, iter,
1720                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
1721                 goto out;
1722         }
1723
1724         if (!i)
1725                 goto out;
1726
1727         if (fsck_err_on(!S_ISDIR(i->inode.bi_mode),
1728                         c, dirent_in_non_dir_inode,
1729                         "dirent in non directory inode type %s:\n%s",
1730                         bch2_d_type_str(inode_d_type(&i->inode)),
1731                         (printbuf_reset(&buf),
1732                          bch2_bkey_val_to_text(&buf, c, k), buf.buf))) {
1733                 ret = bch2_btree_delete_at(trans, iter, 0);
1734                 goto out;
1735         }
1736
1737         ret = hash_check_key(trans, bch2_dirent_hash_desc, hash_info, iter, k);
1738         if (ret < 0)
1739                 goto err;
1740         if (ret) {
1741                 /* dirent has been deleted */
1742                 ret = 0;
1743                 goto out;
1744         }
1745
1746         if (k.k->type != KEY_TYPE_dirent)
1747                 goto out;
1748
1749         d = bkey_s_c_to_dirent(k);
1750
1751         if (d.v->d_type == DT_SUBVOL) {
1752                 struct bch_inode_unpacked subvol_root;
1753                 u32 target_subvol = le32_to_cpu(d.v->d_child_subvol);
1754                 u32 target_snapshot;
1755                 u64 target_inum;
1756
1757                 ret = __subvol_lookup(trans, target_subvol,
1758                                       &target_snapshot, &target_inum);
1759                 if (ret && !bch2_err_matches(ret, ENOENT))
1760                         goto err;
1761
1762                 if (fsck_err_on(ret, c, dirent_to_missing_subvol,
1763                                 "dirent points to missing subvolume %u",
1764                                 le32_to_cpu(d.v->d_child_subvol))) {
1765                         ret = __remove_dirent(trans, d.k->p);
1766                         goto err;
1767                 }
1768
1769                 ret = __lookup_inode(trans, target_inum,
1770                                    &subvol_root, &target_snapshot);
1771                 if (ret && !bch2_err_matches(ret, ENOENT))
1772                         goto err;
1773
1774                 if (fsck_err_on(ret, c, subvol_to_missing_root,
1775                                 "subvolume %u points to missing subvolume root %llu",
1776                                 target_subvol,
1777                                 target_inum)) {
1778                         bch_err(c, "repair not implemented yet");
1779                         ret = -EINVAL;
1780                         goto err;
1781                 }
1782
1783                 if (fsck_err_on(subvol_root.bi_subvol != target_subvol,
1784                                 c, subvol_root_wrong_bi_subvol,
1785                                 "subvol root %llu has wrong bi_subvol field: got %u, should be %u",
1786                                 target_inum,
1787                                 subvol_root.bi_subvol, target_subvol)) {
1788                         subvol_root.bi_subvol = target_subvol;
1789                         ret = __write_inode(trans, &subvol_root, target_snapshot);
1790                         if (ret)
1791                                 goto err;
1792                 }
1793
1794                 ret = check_dirent_target(trans, iter, d, &subvol_root,
1795                                           target_snapshot);
1796                 if (ret)
1797                         goto err;
1798         } else {
1799                 ret = __get_visible_inodes(trans, target, s, le64_to_cpu(d.v->d_inum));
1800                 if (ret)
1801                         goto err;
1802
1803                 if (fsck_err_on(!target->inodes.nr,
1804                                 c, dirent_to_missing_inode,
1805                                 "dirent points to missing inode: (equiv %u)\n%s",
1806                                 equiv.snapshot,
1807                                 (printbuf_reset(&buf),
1808                                  bch2_bkey_val_to_text(&buf, c, k),
1809                                  buf.buf))) {
1810                         ret = __remove_dirent(trans, d.k->p);
1811                         if (ret)
1812                                 goto err;
1813                 }
1814
1815                 darray_for_each(target->inodes, i) {
1816                         ret = check_dirent_target(trans, iter, d,
1817                                                   &i->inode, i->snapshot);
1818                         if (ret)
1819                                 goto err;
1820                 }
1821         }
1822
1823         if (d.v->d_type == DT_DIR)
1824                 for_each_visible_inode(c, s, dir, equiv.snapshot, i)
1825                         i->count++;
1826
1827 out:
1828 err:
1829 fsck_err:
1830         printbuf_exit(&buf);
1831         bch_err_fn(c, ret);
1832         return ret;
1833 }
1834
1835 /*
1836  * Walk dirents: verify that they all have a corresponding S_ISDIR inode,
1837  * validate d_type
1838  */
1839 int bch2_check_dirents(struct bch_fs *c)
1840 {
1841         struct inode_walker dir = inode_walker_init();
1842         struct inode_walker target = inode_walker_init();
1843         struct snapshots_seen s;
1844         struct bch_hash_info hash_info;
1845         struct btree_trans *trans = bch2_trans_get(c);
1846         struct btree_iter iter;
1847         struct bkey_s_c k;
1848         int ret = 0;
1849
1850         snapshots_seen_init(&s);
1851
1852         ret = for_each_btree_key_commit(trans, iter, BTREE_ID_dirents,
1853                         POS(BCACHEFS_ROOT_INO, 0),
1854                         BTREE_ITER_PREFETCH|BTREE_ITER_ALL_SNAPSHOTS,
1855                         k,
1856                         NULL, NULL,
1857                         BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
1858                 check_dirent(trans, &iter, k, &hash_info, &dir, &target, &s));
1859
1860         bch2_trans_put(trans);
1861         snapshots_seen_exit(&s);
1862         inode_walker_exit(&dir);
1863         inode_walker_exit(&target);
1864         bch_err_fn(c, ret);
1865         return ret;
1866 }
1867
1868 static int check_xattr(struct btree_trans *trans, struct btree_iter *iter,
1869                        struct bkey_s_c k,
1870                        struct bch_hash_info *hash_info,
1871                        struct inode_walker *inode)
1872 {
1873         struct bch_fs *c = trans->c;
1874         struct inode_walker_entry *i;
1875         int ret;
1876
1877         ret = check_key_has_snapshot(trans, iter, k);
1878         if (ret)
1879                 return ret;
1880
1881         i = walk_inode(trans, inode, k.k->p, k.k->type == KEY_TYPE_whiteout);
1882         ret = PTR_ERR_OR_ZERO(i);
1883         if (ret)
1884                 return ret;
1885
1886         if (inode->first_this_inode && inode->inodes.nr)
1887                 *hash_info = bch2_hash_info_init(c, &inode->inodes.data[0].inode);
1888         inode->first_this_inode = false;
1889
1890         if (fsck_err_on(!i, c, xattr_in_missing_inode,
1891                         "xattr for missing inode %llu",
1892                         k.k->p.inode))
1893                 return bch2_btree_delete_at(trans, iter, 0);
1894
1895         if (!i)
1896                 return 0;
1897
1898         ret = hash_check_key(trans, bch2_xattr_hash_desc, hash_info, iter, k);
1899 fsck_err:
1900         bch_err_fn(c, ret);
1901         return ret;
1902 }
1903
1904 /*
1905  * Walk xattrs: verify that they all have a corresponding inode
1906  */
1907 int bch2_check_xattrs(struct bch_fs *c)
1908 {
1909         struct inode_walker inode = inode_walker_init();
1910         struct bch_hash_info hash_info;
1911         struct btree_iter iter;
1912         struct bkey_s_c k;
1913         int ret = 0;
1914
1915         ret = bch2_trans_run(c,
1916                 for_each_btree_key_commit(trans, iter, BTREE_ID_xattrs,
1917                         POS(BCACHEFS_ROOT_INO, 0),
1918                         BTREE_ITER_PREFETCH|BTREE_ITER_ALL_SNAPSHOTS,
1919                         k,
1920                         NULL, NULL,
1921                         BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
1922                 check_xattr(trans, &iter, k, &hash_info, &inode)));
1923         bch_err_fn(c, ret);
1924         return ret;
1925 }
1926
1927 static int check_root_trans(struct btree_trans *trans)
1928 {
1929         struct bch_fs *c = trans->c;
1930         struct bch_inode_unpacked root_inode;
1931         u32 snapshot;
1932         u64 inum;
1933         int ret;
1934
1935         ret = __subvol_lookup(trans, BCACHEFS_ROOT_SUBVOL, &snapshot, &inum);
1936         if (ret && !bch2_err_matches(ret, ENOENT))
1937                 return ret;
1938
1939         if (mustfix_fsck_err_on(ret, c, root_subvol_missing,
1940                                 "root subvol missing")) {
1941                 struct bkey_i_subvolume root_subvol;
1942
1943                 snapshot        = U32_MAX;
1944                 inum            = BCACHEFS_ROOT_INO;
1945
1946                 bkey_subvolume_init(&root_subvol.k_i);
1947                 root_subvol.k.p.offset = BCACHEFS_ROOT_SUBVOL;
1948                 root_subvol.v.flags     = 0;
1949                 root_subvol.v.snapshot  = cpu_to_le32(snapshot);
1950                 root_subvol.v.inode     = cpu_to_le64(inum);
1951                 ret = commit_do(trans, NULL, NULL,
1952                                       BTREE_INSERT_NOFAIL|
1953                                       BTREE_INSERT_LAZY_RW,
1954                         bch2_btree_insert_trans(trans, BTREE_ID_subvolumes,
1955                                             &root_subvol.k_i, 0));
1956                 bch_err_msg(c, ret, "writing root subvol");
1957                 if (ret)
1958                         goto err;
1959
1960         }
1961
1962         ret = __lookup_inode(trans, BCACHEFS_ROOT_INO, &root_inode, &snapshot);
1963         if (ret && !bch2_err_matches(ret, ENOENT))
1964                 return ret;
1965
1966         if (mustfix_fsck_err_on(ret, c, root_dir_missing,
1967                                 "root directory missing") ||
1968             mustfix_fsck_err_on(!S_ISDIR(root_inode.bi_mode),
1969                                 c, root_inode_not_dir,
1970                                 "root inode not a directory")) {
1971                 bch2_inode_init(c, &root_inode, 0, 0, S_IFDIR|0755,
1972                                 0, NULL);
1973                 root_inode.bi_inum = inum;
1974
1975                 ret = __write_inode(trans, &root_inode, snapshot);
1976                 bch_err_msg(c, ret, "writing root inode");
1977         }
1978 err:
1979 fsck_err:
1980         return ret;
1981 }
1982
1983 /* Get root directory, create if it doesn't exist: */
1984 int bch2_check_root(struct bch_fs *c)
1985 {
1986         int ret;
1987
1988         ret = bch2_trans_do(c, NULL, NULL,
1989                              BTREE_INSERT_NOFAIL|
1990                              BTREE_INSERT_LAZY_RW,
1991                 check_root_trans(trans));
1992         bch_err_fn(c, ret);
1993         return ret;
1994 }
1995
1996 struct pathbuf_entry {
1997         u64     inum;
1998         u32     snapshot;
1999 };
2000
2001 typedef DARRAY(struct pathbuf_entry) pathbuf;
2002
2003 static bool path_is_dup(pathbuf *p, u64 inum, u32 snapshot)
2004 {
2005         struct pathbuf_entry *i;
2006
2007         darray_for_each(*p, i)
2008                 if (i->inum     == inum &&
2009                     i->snapshot == snapshot)
2010                         return true;
2011
2012         return false;
2013 }
2014
2015 static int path_down(struct bch_fs *c, pathbuf *p,
2016                      u64 inum, u32 snapshot)
2017 {
2018         int ret = darray_push(p, ((struct pathbuf_entry) {
2019                 .inum           = inum,
2020                 .snapshot       = snapshot,
2021         }));
2022
2023         if (ret)
2024                 bch_err(c, "fsck: error allocating memory for pathbuf, size %zu",
2025                         p->size);
2026         return ret;
2027 }
2028
2029 /*
2030  * Check that a given inode is reachable from the root:
2031  *
2032  * XXX: we should also be verifying that inodes are in the right subvolumes
2033  */
2034 static int check_path(struct btree_trans *trans,
2035                       pathbuf *p,
2036                       struct bch_inode_unpacked *inode,
2037                       u32 snapshot)
2038 {
2039         struct bch_fs *c = trans->c;
2040         int ret = 0;
2041
2042         snapshot = bch2_snapshot_equiv(c, snapshot);
2043         p->nr = 0;
2044
2045         while (!(inode->bi_inum == BCACHEFS_ROOT_INO &&
2046                  inode->bi_subvol == BCACHEFS_ROOT_SUBVOL)) {
2047                 struct btree_iter dirent_iter;
2048                 struct bkey_s_c_dirent d;
2049                 u32 parent_snapshot = snapshot;
2050
2051                 if (inode->bi_subvol) {
2052                         u64 inum;
2053
2054                         ret = subvol_lookup(trans, inode->bi_parent_subvol,
2055                                             &parent_snapshot, &inum);
2056                         if (ret)
2057                                 break;
2058                 }
2059
2060                 ret = lockrestart_do(trans,
2061                         PTR_ERR_OR_ZERO((d = dirent_get_by_pos(trans, &dirent_iter,
2062                                           SPOS(inode->bi_dir, inode->bi_dir_offset,
2063                                                parent_snapshot))).k));
2064                 if (ret && !bch2_err_matches(ret, ENOENT))
2065                         break;
2066
2067                 if (!ret && !dirent_points_to_inode(d, inode)) {
2068                         bch2_trans_iter_exit(trans, &dirent_iter);
2069                         ret = -BCH_ERR_ENOENT_dirent_doesnt_match_inode;
2070                 }
2071
2072                 if (bch2_err_matches(ret, ENOENT)) {
2073                         if (fsck_err(c,  inode_unreachable,
2074                                      "unreachable inode %llu:%u, type %s nlink %u backptr %llu:%llu",
2075                                      inode->bi_inum, snapshot,
2076                                      bch2_d_type_str(inode_d_type(inode)),
2077                                      inode->bi_nlink,
2078                                      inode->bi_dir,
2079                                      inode->bi_dir_offset))
2080                                 ret = reattach_inode(trans, inode, snapshot);
2081                         break;
2082                 }
2083
2084                 bch2_trans_iter_exit(trans, &dirent_iter);
2085
2086                 if (!S_ISDIR(inode->bi_mode))
2087                         break;
2088
2089                 ret = path_down(c, p, inode->bi_inum, snapshot);
2090                 if (ret) {
2091                         bch_err(c, "memory allocation failure");
2092                         return ret;
2093                 }
2094
2095                 snapshot = parent_snapshot;
2096
2097                 ret = lookup_inode(trans, inode->bi_dir, inode, &snapshot);
2098                 if (ret) {
2099                         /* Should have been caught in dirents pass */
2100                         bch_err(c, "error looking up parent directory: %i", ret);
2101                         break;
2102                 }
2103
2104                 if (path_is_dup(p, inode->bi_inum, snapshot)) {
2105                         struct pathbuf_entry *i;
2106
2107                         /* XXX print path */
2108                         bch_err(c, "directory structure loop");
2109
2110                         darray_for_each(*p, i)
2111                                 pr_err("%llu:%u", i->inum, i->snapshot);
2112                         pr_err("%llu:%u", inode->bi_inum, snapshot);
2113
2114                         if (!fsck_err(c, dir_loop,
2115                                       "directory structure loop"))
2116                                 return 0;
2117
2118                         ret = commit_do(trans, NULL, NULL,
2119                                               BTREE_INSERT_NOFAIL|
2120                                               BTREE_INSERT_LAZY_RW,
2121                                         remove_backpointer(trans, inode));
2122                         if (ret) {
2123                                 bch_err(c, "error removing dirent: %i", ret);
2124                                 break;
2125                         }
2126
2127                         ret = reattach_inode(trans, inode, snapshot);
2128                 }
2129         }
2130 fsck_err:
2131         bch_err_fn(c, ret);
2132         return ret;
2133 }
2134
2135 /*
2136  * Check for unreachable inodes, as well as loops in the directory structure:
2137  * After bch2_check_dirents(), if an inode backpointer doesn't exist that means it's
2138  * unreachable:
2139  */
2140 int bch2_check_directory_structure(struct bch_fs *c)
2141 {
2142         struct btree_trans *trans = bch2_trans_get(c);
2143         struct btree_iter iter;
2144         struct bkey_s_c k;
2145         struct bch_inode_unpacked u;
2146         pathbuf path = { 0, };
2147         int ret;
2148
2149         for_each_btree_key(trans, iter, BTREE_ID_inodes, POS_MIN,
2150                            BTREE_ITER_INTENT|
2151                            BTREE_ITER_PREFETCH|
2152                            BTREE_ITER_ALL_SNAPSHOTS, k, ret) {
2153                 if (!bkey_is_inode(k.k))
2154                         continue;
2155
2156                 ret = bch2_inode_unpack(k, &u);
2157                 if (ret) {
2158                         /* Should have been caught earlier in fsck: */
2159                         bch_err(c, "error unpacking inode %llu: %i", k.k->p.offset, ret);
2160                         break;
2161                 }
2162
2163                 if (u.bi_flags & BCH_INODE_unlinked)
2164                         continue;
2165
2166                 ret = check_path(trans, &path, &u, iter.pos.snapshot);
2167                 if (ret)
2168                         break;
2169         }
2170         bch2_trans_iter_exit(trans, &iter);
2171         bch2_trans_put(trans);
2172         darray_exit(&path);
2173         bch_err_fn(c, ret);
2174         return ret;
2175 }
2176
2177 struct nlink_table {
2178         size_t          nr;
2179         size_t          size;
2180
2181         struct nlink {
2182                 u64     inum;
2183                 u32     snapshot;
2184                 u32     count;
2185         }               *d;
2186 };
2187
2188 static int add_nlink(struct bch_fs *c, struct nlink_table *t,
2189                      u64 inum, u32 snapshot)
2190 {
2191         if (t->nr == t->size) {
2192                 size_t new_size = max_t(size_t, 128UL, t->size * 2);
2193                 void *d = kvmalloc_array(new_size, sizeof(t->d[0]), GFP_KERNEL);
2194
2195                 if (!d) {
2196                         bch_err(c, "fsck: error allocating memory for nlink_table, size %zu",
2197                                 new_size);
2198                         return -BCH_ERR_ENOMEM_fsck_add_nlink;
2199                 }
2200
2201                 if (t->d)
2202                         memcpy(d, t->d, t->size * sizeof(t->d[0]));
2203                 kvfree(t->d);
2204
2205                 t->d = d;
2206                 t->size = new_size;
2207         }
2208
2209
2210         t->d[t->nr++] = (struct nlink) {
2211                 .inum           = inum,
2212                 .snapshot       = snapshot,
2213         };
2214
2215         return 0;
2216 }
2217
2218 static int nlink_cmp(const void *_l, const void *_r)
2219 {
2220         const struct nlink *l = _l;
2221         const struct nlink *r = _r;
2222
2223         return cmp_int(l->inum, r->inum) ?: cmp_int(l->snapshot, r->snapshot);
2224 }
2225
2226 static void inc_link(struct bch_fs *c, struct snapshots_seen *s,
2227                      struct nlink_table *links,
2228                      u64 range_start, u64 range_end, u64 inum, u32 snapshot)
2229 {
2230         struct nlink *link, key = {
2231                 .inum = inum, .snapshot = U32_MAX,
2232         };
2233
2234         if (inum < range_start || inum >= range_end)
2235                 return;
2236
2237         link = __inline_bsearch(&key, links->d, links->nr,
2238                                 sizeof(links->d[0]), nlink_cmp);
2239         if (!link)
2240                 return;
2241
2242         while (link > links->d && link[0].inum == link[-1].inum)
2243                 --link;
2244
2245         for (; link < links->d + links->nr && link->inum == inum; link++)
2246                 if (ref_visible(c, s, snapshot, link->snapshot)) {
2247                         link->count++;
2248                         if (link->snapshot >= snapshot)
2249                                 break;
2250                 }
2251 }
2252
2253 noinline_for_stack
2254 static int check_nlinks_find_hardlinks(struct bch_fs *c,
2255                                        struct nlink_table *t,
2256                                        u64 start, u64 *end)
2257 {
2258         struct btree_trans *trans = bch2_trans_get(c);
2259         struct btree_iter iter;
2260         struct bkey_s_c k;
2261         struct bch_inode_unpacked u;
2262         int ret = 0;
2263
2264         for_each_btree_key(trans, iter, BTREE_ID_inodes,
2265                            POS(0, start),
2266                            BTREE_ITER_INTENT|
2267                            BTREE_ITER_PREFETCH|
2268                            BTREE_ITER_ALL_SNAPSHOTS, k, ret) {
2269                 if (!bkey_is_inode(k.k))
2270                         continue;
2271
2272                 /* Should never fail, checked by bch2_inode_invalid: */
2273                 BUG_ON(bch2_inode_unpack(k, &u));
2274
2275                 /*
2276                  * Backpointer and directory structure checks are sufficient for
2277                  * directories, since they can't have hardlinks:
2278                  */
2279                 if (S_ISDIR(u.bi_mode))
2280                         continue;
2281
2282                 if (!u.bi_nlink)
2283                         continue;
2284
2285                 ret = add_nlink(c, t, k.k->p.offset, k.k->p.snapshot);
2286                 if (ret) {
2287                         *end = k.k->p.offset;
2288                         ret = 0;
2289                         break;
2290                 }
2291
2292         }
2293         bch2_trans_iter_exit(trans, &iter);
2294         bch2_trans_put(trans);
2295
2296         if (ret)
2297                 bch_err(c, "error in fsck: btree error %i while walking inodes", ret);
2298
2299         return ret;
2300 }
2301
2302 noinline_for_stack
2303 static int check_nlinks_walk_dirents(struct bch_fs *c, struct nlink_table *links,
2304                                      u64 range_start, u64 range_end)
2305 {
2306         struct btree_trans *trans = bch2_trans_get(c);
2307         struct snapshots_seen s;
2308         struct btree_iter iter;
2309         struct bkey_s_c k;
2310         struct bkey_s_c_dirent d;
2311         int ret;
2312
2313         snapshots_seen_init(&s);
2314
2315         for_each_btree_key(trans, iter, BTREE_ID_dirents, POS_MIN,
2316                            BTREE_ITER_INTENT|
2317                            BTREE_ITER_PREFETCH|
2318                            BTREE_ITER_ALL_SNAPSHOTS, k, ret) {
2319                 ret = snapshots_seen_update(c, &s, iter.btree_id, k.k->p);
2320                 if (ret)
2321                         break;
2322
2323                 switch (k.k->type) {
2324                 case KEY_TYPE_dirent:
2325                         d = bkey_s_c_to_dirent(k);
2326
2327                         if (d.v->d_type != DT_DIR &&
2328                             d.v->d_type != DT_SUBVOL)
2329                                 inc_link(c, &s, links, range_start, range_end,
2330                                          le64_to_cpu(d.v->d_inum),
2331                                          bch2_snapshot_equiv(c, d.k->p.snapshot));
2332                         break;
2333                 }
2334         }
2335         bch2_trans_iter_exit(trans, &iter);
2336
2337         if (ret)
2338                 bch_err(c, "error in fsck: btree error %i while walking dirents", ret);
2339
2340         bch2_trans_put(trans);
2341         snapshots_seen_exit(&s);
2342         return ret;
2343 }
2344
2345 static int check_nlinks_update_inode(struct btree_trans *trans, struct btree_iter *iter,
2346                                      struct bkey_s_c k,
2347                                      struct nlink_table *links,
2348                                      size_t *idx, u64 range_end)
2349 {
2350         struct bch_fs *c = trans->c;
2351         struct bch_inode_unpacked u;
2352         struct nlink *link = &links->d[*idx];
2353         int ret = 0;
2354
2355         if (k.k->p.offset >= range_end)
2356                 return 1;
2357
2358         if (!bkey_is_inode(k.k))
2359                 return 0;
2360
2361         BUG_ON(bch2_inode_unpack(k, &u));
2362
2363         if (S_ISDIR(u.bi_mode))
2364                 return 0;
2365
2366         if (!u.bi_nlink)
2367                 return 0;
2368
2369         while ((cmp_int(link->inum, k.k->p.offset) ?:
2370                 cmp_int(link->snapshot, k.k->p.snapshot)) < 0) {
2371                 BUG_ON(*idx == links->nr);
2372                 link = &links->d[++*idx];
2373         }
2374
2375         if (fsck_err_on(bch2_inode_nlink_get(&u) != link->count,
2376                         c, inode_wrong_nlink,
2377                         "inode %llu type %s has wrong i_nlink (%u, should be %u)",
2378                         u.bi_inum, bch2_d_types[mode_to_type(u.bi_mode)],
2379                         bch2_inode_nlink_get(&u), link->count)) {
2380                 bch2_inode_nlink_set(&u, link->count);
2381                 ret = __write_inode(trans, &u, k.k->p.snapshot);
2382         }
2383 fsck_err:
2384         return ret;
2385 }
2386
2387 noinline_for_stack
2388 static int check_nlinks_update_hardlinks(struct bch_fs *c,
2389                                struct nlink_table *links,
2390                                u64 range_start, u64 range_end)
2391 {
2392         struct btree_iter iter;
2393         struct bkey_s_c k;
2394         size_t idx = 0;
2395         int ret = 0;
2396
2397         ret = bch2_trans_run(c,
2398                 for_each_btree_key_commit(trans, iter, BTREE_ID_inodes,
2399                                 POS(0, range_start),
2400                                 BTREE_ITER_INTENT|BTREE_ITER_PREFETCH|BTREE_ITER_ALL_SNAPSHOTS, k,
2401                                 NULL, NULL, BTREE_INSERT_LAZY_RW|BTREE_INSERT_NOFAIL,
2402                         check_nlinks_update_inode(trans, &iter, k, links, &idx, range_end)));
2403         if (ret < 0) {
2404                 bch_err(c, "error in fsck: btree error %i while walking inodes", ret);
2405                 return ret;
2406         }
2407
2408         return 0;
2409 }
2410
2411 int bch2_check_nlinks(struct bch_fs *c)
2412 {
2413         struct nlink_table links = { 0 };
2414         u64 this_iter_range_start, next_iter_range_start = 0;
2415         int ret = 0;
2416
2417         do {
2418                 this_iter_range_start = next_iter_range_start;
2419                 next_iter_range_start = U64_MAX;
2420
2421                 ret = check_nlinks_find_hardlinks(c, &links,
2422                                                   this_iter_range_start,
2423                                                   &next_iter_range_start);
2424
2425                 ret = check_nlinks_walk_dirents(c, &links,
2426                                           this_iter_range_start,
2427                                           next_iter_range_start);
2428                 if (ret)
2429                         break;
2430
2431                 ret = check_nlinks_update_hardlinks(c, &links,
2432                                          this_iter_range_start,
2433                                          next_iter_range_start);
2434                 if (ret)
2435                         break;
2436
2437                 links.nr = 0;
2438         } while (next_iter_range_start != U64_MAX);
2439
2440         kvfree(links.d);
2441         bch_err_fn(c, ret);
2442         return ret;
2443 }
2444
2445 static int fix_reflink_p_key(struct btree_trans *trans, struct btree_iter *iter,
2446                              struct bkey_s_c k)
2447 {
2448         struct bkey_s_c_reflink_p p;
2449         struct bkey_i_reflink_p *u;
2450         int ret;
2451
2452         if (k.k->type != KEY_TYPE_reflink_p)
2453                 return 0;
2454
2455         p = bkey_s_c_to_reflink_p(k);
2456
2457         if (!p.v->front_pad && !p.v->back_pad)
2458                 return 0;
2459
2460         u = bch2_trans_kmalloc(trans, sizeof(*u));
2461         ret = PTR_ERR_OR_ZERO(u);
2462         if (ret)
2463                 return ret;
2464
2465         bkey_reassemble(&u->k_i, k);
2466         u->v.front_pad  = 0;
2467         u->v.back_pad   = 0;
2468
2469         return bch2_trans_update(trans, iter, &u->k_i, BTREE_TRIGGER_NORUN);
2470 }
2471
2472 int bch2_fix_reflink_p(struct bch_fs *c)
2473 {
2474         struct btree_iter iter;
2475         struct bkey_s_c k;
2476         int ret;
2477
2478         if (c->sb.version >= bcachefs_metadata_version_reflink_p_fix)
2479                 return 0;
2480
2481         ret = bch2_trans_run(c,
2482                 for_each_btree_key_commit(trans, iter,
2483                                 BTREE_ID_extents, POS_MIN,
2484                                 BTREE_ITER_INTENT|BTREE_ITER_PREFETCH|
2485                                 BTREE_ITER_ALL_SNAPSHOTS, k,
2486                                 NULL, NULL, BTREE_INSERT_NOFAIL|BTREE_INSERT_LAZY_RW,
2487                         fix_reflink_p_key(trans, &iter, k)));
2488         bch_err_fn(c, ret);
2489         return ret;
2490 }