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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2014 Facebook. All rights reserved.
4 */
5
6#include <linux/sched.h>
7#include <linux/stacktrace.h>
8#include "ctree.h"
9#include "disk-io.h"
10#include "locking.h"
11#include "delayed-ref.h"
12#include "ref-verify.h"
13
14/*
15 * Used to keep track the roots and number of refs each root has for a given
16 * bytenr. This just tracks the number of direct references, no shared
17 * references.
18 */
19struct root_entry {
20 u64 root_objectid;
21 u64 num_refs;
22 struct rb_node node;
23};
24
25/*
26 * These are meant to represent what should exist in the extent tree, these can
27 * be used to verify the extent tree is consistent as these should all match
28 * what the extent tree says.
29 */
30struct ref_entry {
31 u64 root_objectid;
32 u64 parent;
33 u64 owner;
34 u64 offset;
35 u64 num_refs;
36 struct rb_node node;
37};
38
39#define MAX_TRACE 16
40
41/*
42 * Whenever we add/remove a reference we record the action. The action maps
43 * back to the delayed ref action. We hold the ref we are changing in the
44 * action so we can account for the history properly, and we record the root we
45 * were called with since it could be different from ref_root. We also store
46 * stack traces because that's how I roll.
47 */
48struct ref_action {
49 int action;
50 u64 root;
51 struct ref_entry ref;
52 struct list_head list;
53 unsigned long trace[MAX_TRACE];
54 unsigned int trace_len;
55};
56
57/*
58 * One of these for every block we reference, it holds the roots and references
59 * to it as well as all of the ref actions that have occurred to it. We never
60 * free it until we unmount the file system in order to make sure re-allocations
61 * are happening properly.
62 */
63struct block_entry {
64 u64 bytenr;
65 u64 len;
66 u64 num_refs;
67 int metadata;
68 int from_disk;
69 struct rb_root roots;
70 struct rb_root refs;
71 struct rb_node node;
72 struct list_head actions;
73};
74
75static struct block_entry *insert_block_entry(struct rb_root *root,
76 struct block_entry *be)
77{
78 struct rb_node **p = &root->rb_node;
79 struct rb_node *parent_node = NULL;
80 struct block_entry *entry;
81
82 while (*p) {
83 parent_node = *p;
84 entry = rb_entry(parent_node, struct block_entry, node);
85 if (entry->bytenr > be->bytenr)
86 p = &(*p)->rb_left;
87 else if (entry->bytenr < be->bytenr)
88 p = &(*p)->rb_right;
89 else
90 return entry;
91 }
92
93 rb_link_node(&be->node, parent_node, p);
94 rb_insert_color(&be->node, root);
95 return NULL;
96}
97
98static struct block_entry *lookup_block_entry(struct rb_root *root, u64 bytenr)
99{
100 struct rb_node *n;
101 struct block_entry *entry = NULL;
102
103 n = root->rb_node;
104 while (n) {
105 entry = rb_entry(n, struct block_entry, node);
106 if (entry->bytenr < bytenr)
107 n = n->rb_right;
108 else if (entry->bytenr > bytenr)
109 n = n->rb_left;
110 else
111 return entry;
112 }
113 return NULL;
114}
115
116static struct root_entry *insert_root_entry(struct rb_root *root,
117 struct root_entry *re)
118{
119 struct rb_node **p = &root->rb_node;
120 struct rb_node *parent_node = NULL;
121 struct root_entry *entry;
122
123 while (*p) {
124 parent_node = *p;
125 entry = rb_entry(parent_node, struct root_entry, node);
126 if (entry->root_objectid > re->root_objectid)
127 p = &(*p)->rb_left;
128 else if (entry->root_objectid < re->root_objectid)
129 p = &(*p)->rb_right;
130 else
131 return entry;
132 }
133
134 rb_link_node(&re->node, parent_node, p);
135 rb_insert_color(&re->node, root);
136 return NULL;
137
138}
139
140static int comp_refs(struct ref_entry *ref1, struct ref_entry *ref2)
141{
142 if (ref1->root_objectid < ref2->root_objectid)
143 return -1;
144 if (ref1->root_objectid > ref2->root_objectid)
145 return 1;
146 if (ref1->parent < ref2->parent)
147 return -1;
148 if (ref1->parent > ref2->parent)
149 return 1;
150 if (ref1->owner < ref2->owner)
151 return -1;
152 if (ref1->owner > ref2->owner)
153 return 1;
154 if (ref1->offset < ref2->offset)
155 return -1;
156 if (ref1->offset > ref2->offset)
157 return 1;
158 return 0;
159}
160
161static struct ref_entry *insert_ref_entry(struct rb_root *root,
162 struct ref_entry *ref)
163{
164 struct rb_node **p = &root->rb_node;
165 struct rb_node *parent_node = NULL;
166 struct ref_entry *entry;
167 int cmp;
168
169 while (*p) {
170 parent_node = *p;
171 entry = rb_entry(parent_node, struct ref_entry, node);
172 cmp = comp_refs(entry, ref);
173 if (cmp > 0)
174 p = &(*p)->rb_left;
175 else if (cmp < 0)
176 p = &(*p)->rb_right;
177 else
178 return entry;
179 }
180
181 rb_link_node(&ref->node, parent_node, p);
182 rb_insert_color(&ref->node, root);
183 return NULL;
184
185}
186
187static struct root_entry *lookup_root_entry(struct rb_root *root, u64 objectid)
188{
189 struct rb_node *n;
190 struct root_entry *entry = NULL;
191
192 n = root->rb_node;
193 while (n) {
194 entry = rb_entry(n, struct root_entry, node);
195 if (entry->root_objectid < objectid)
196 n = n->rb_right;
197 else if (entry->root_objectid > objectid)
198 n = n->rb_left;
199 else
200 return entry;
201 }
202 return NULL;
203}
204
205#ifdef CONFIG_STACKTRACE
206static void __save_stack_trace(struct ref_action *ra)
207{
208 ra->trace_len = stack_trace_save(ra->trace, MAX_TRACE, 2);
209}
210
211static void __print_stack_trace(struct btrfs_fs_info *fs_info,
212 struct ref_action *ra)
213{
214 if (ra->trace_len == 0) {
215 btrfs_err(fs_info, " ref-verify: no stacktrace");
216 return;
217 }
218 stack_trace_print(ra->trace, ra->trace_len, 2);
219}
220#else
221static inline void __save_stack_trace(struct ref_action *ra)
222{
223}
224
225static inline void __print_stack_trace(struct btrfs_fs_info *fs_info,
226 struct ref_action *ra)
227{
228 btrfs_err(fs_info, " ref-verify: no stacktrace support");
229}
230#endif
231
232static void free_block_entry(struct block_entry *be)
233{
234 struct root_entry *re;
235 struct ref_entry *ref;
236 struct ref_action *ra;
237 struct rb_node *n;
238
239 while ((n = rb_first(&be->roots))) {
240 re = rb_entry(n, struct root_entry, node);
241 rb_erase(&re->node, &be->roots);
242 kfree(re);
243 }
244
245 while((n = rb_first(&be->refs))) {
246 ref = rb_entry(n, struct ref_entry, node);
247 rb_erase(&ref->node, &be->refs);
248 kfree(ref);
249 }
250
251 while (!list_empty(&be->actions)) {
252 ra = list_first_entry(&be->actions, struct ref_action,
253 list);
254 list_del(&ra->list);
255 kfree(ra);
256 }
257 kfree(be);
258}
259
260static struct block_entry *add_block_entry(struct btrfs_fs_info *fs_info,
261 u64 bytenr, u64 len,
262 u64 root_objectid)
263{
264 struct block_entry *be = NULL, *exist;
265 struct root_entry *re = NULL;
266
267 re = kzalloc(sizeof(struct root_entry), GFP_KERNEL);
268 be = kzalloc(sizeof(struct block_entry), GFP_KERNEL);
269 if (!be || !re) {
270 kfree(re);
271 kfree(be);
272 return ERR_PTR(-ENOMEM);
273 }
274 be->bytenr = bytenr;
275 be->len = len;
276
277 re->root_objectid = root_objectid;
278 re->num_refs = 0;
279
280 spin_lock(&fs_info->ref_verify_lock);
281 exist = insert_block_entry(&fs_info->block_tree, be);
282 if (exist) {
283 if (root_objectid) {
284 struct root_entry *exist_re;
285
286 exist_re = insert_root_entry(&exist->roots, re);
287 if (exist_re)
288 kfree(re);
289 } else {
290 kfree(re);
291 }
292 kfree(be);
293 return exist;
294 }
295
296 be->num_refs = 0;
297 be->metadata = 0;
298 be->from_disk = 0;
299 be->roots = RB_ROOT;
300 be->refs = RB_ROOT;
301 INIT_LIST_HEAD(&be->actions);
302 if (root_objectid)
303 insert_root_entry(&be->roots, re);
304 else
305 kfree(re);
306 return be;
307}
308
309static int add_tree_block(struct btrfs_fs_info *fs_info, u64 ref_root,
310 u64 parent, u64 bytenr, int level)
311{
312 struct block_entry *be;
313 struct root_entry *re;
314 struct ref_entry *ref = NULL, *exist;
315
316 ref = kmalloc(sizeof(struct ref_entry), GFP_KERNEL);
317 if (!ref)
318 return -ENOMEM;
319
320 if (parent)
321 ref->root_objectid = 0;
322 else
323 ref->root_objectid = ref_root;
324 ref->parent = parent;
325 ref->owner = level;
326 ref->offset = 0;
327 ref->num_refs = 1;
328
329 be = add_block_entry(fs_info, bytenr, fs_info->nodesize, ref_root);
330 if (IS_ERR(be)) {
331 kfree(ref);
332 return PTR_ERR(be);
333 }
334 be->num_refs++;
335 be->from_disk = 1;
336 be->metadata = 1;
337
338 if (!parent) {
339 ASSERT(ref_root);
340 re = lookup_root_entry(&be->roots, ref_root);
341 ASSERT(re);
342 re->num_refs++;
343 }
344 exist = insert_ref_entry(&be->refs, ref);
345 if (exist) {
346 exist->num_refs++;
347 kfree(ref);
348 }
349 spin_unlock(&fs_info->ref_verify_lock);
350
351 return 0;
352}
353
354static int add_shared_data_ref(struct btrfs_fs_info *fs_info,
355 u64 parent, u32 num_refs, u64 bytenr,
356 u64 num_bytes)
357{
358 struct block_entry *be;
359 struct ref_entry *ref;
360
361 ref = kzalloc(sizeof(struct ref_entry), GFP_KERNEL);
362 if (!ref)
363 return -ENOMEM;
364 be = add_block_entry(fs_info, bytenr, num_bytes, 0);
365 if (IS_ERR(be)) {
366 kfree(ref);
367 return PTR_ERR(be);
368 }
369 be->num_refs += num_refs;
370
371 ref->parent = parent;
372 ref->num_refs = num_refs;
373 if (insert_ref_entry(&be->refs, ref)) {
374 spin_unlock(&fs_info->ref_verify_lock);
375 btrfs_err(fs_info, "existing shared ref when reading from disk?");
376 kfree(ref);
377 return -EINVAL;
378 }
379 spin_unlock(&fs_info->ref_verify_lock);
380 return 0;
381}
382
383static int add_extent_data_ref(struct btrfs_fs_info *fs_info,
384 struct extent_buffer *leaf,
385 struct btrfs_extent_data_ref *dref,
386 u64 bytenr, u64 num_bytes)
387{
388 struct block_entry *be;
389 struct ref_entry *ref;
390 struct root_entry *re;
391 u64 ref_root = btrfs_extent_data_ref_root(leaf, dref);
392 u64 owner = btrfs_extent_data_ref_objectid(leaf, dref);
393 u64 offset = btrfs_extent_data_ref_offset(leaf, dref);
394 u32 num_refs = btrfs_extent_data_ref_count(leaf, dref);
395
396 ref = kzalloc(sizeof(struct ref_entry), GFP_KERNEL);
397 if (!ref)
398 return -ENOMEM;
399 be = add_block_entry(fs_info, bytenr, num_bytes, ref_root);
400 if (IS_ERR(be)) {
401 kfree(ref);
402 return PTR_ERR(be);
403 }
404 be->num_refs += num_refs;
405
406 ref->parent = 0;
407 ref->owner = owner;
408 ref->root_objectid = ref_root;
409 ref->offset = offset;
410 ref->num_refs = num_refs;
411 if (insert_ref_entry(&be->refs, ref)) {
412 spin_unlock(&fs_info->ref_verify_lock);
413 btrfs_err(fs_info, "existing ref when reading from disk?");
414 kfree(ref);
415 return -EINVAL;
416 }
417
418 re = lookup_root_entry(&be->roots, ref_root);
419 if (!re) {
420 spin_unlock(&fs_info->ref_verify_lock);
421 btrfs_err(fs_info, "missing root in new block entry?");
422 return -EINVAL;
423 }
424 re->num_refs += num_refs;
425 spin_unlock(&fs_info->ref_verify_lock);
426 return 0;
427}
428
429static int process_extent_item(struct btrfs_fs_info *fs_info,
430 struct btrfs_path *path, struct btrfs_key *key,
431 int slot, int *tree_block_level)
432{
433 struct btrfs_extent_item *ei;
434 struct btrfs_extent_inline_ref *iref;
435 struct btrfs_extent_data_ref *dref;
436 struct btrfs_shared_data_ref *sref;
437 struct extent_buffer *leaf = path->nodes[0];
438 u32 item_size = btrfs_item_size_nr(leaf, slot);
439 unsigned long end, ptr;
440 u64 offset, flags, count;
441 int type, ret;
442
443 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
444 flags = btrfs_extent_flags(leaf, ei);
445
446 if ((key->type == BTRFS_EXTENT_ITEM_KEY) &&
447 flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
448 struct btrfs_tree_block_info *info;
449
450 info = (struct btrfs_tree_block_info *)(ei + 1);
451 *tree_block_level = btrfs_tree_block_level(leaf, info);
452 iref = (struct btrfs_extent_inline_ref *)(info + 1);
453 } else {
454 if (key->type == BTRFS_METADATA_ITEM_KEY)
455 *tree_block_level = key->offset;
456 iref = (struct btrfs_extent_inline_ref *)(ei + 1);
457 }
458
459 ptr = (unsigned long)iref;
460 end = (unsigned long)ei + item_size;
461 while (ptr < end) {
462 iref = (struct btrfs_extent_inline_ref *)ptr;
463 type = btrfs_extent_inline_ref_type(leaf, iref);
464 offset = btrfs_extent_inline_ref_offset(leaf, iref);
465 switch (type) {
466 case BTRFS_TREE_BLOCK_REF_KEY:
467 ret = add_tree_block(fs_info, offset, 0, key->objectid,
468 *tree_block_level);
469 break;
470 case BTRFS_SHARED_BLOCK_REF_KEY:
471 ret = add_tree_block(fs_info, 0, offset, key->objectid,
472 *tree_block_level);
473 break;
474 case BTRFS_EXTENT_DATA_REF_KEY:
475 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
476 ret = add_extent_data_ref(fs_info, leaf, dref,
477 key->objectid, key->offset);
478 break;
479 case BTRFS_SHARED_DATA_REF_KEY:
480 sref = (struct btrfs_shared_data_ref *)(iref + 1);
481 count = btrfs_shared_data_ref_count(leaf, sref);
482 ret = add_shared_data_ref(fs_info, offset, count,
483 key->objectid, key->offset);
484 break;
485 default:
486 btrfs_err(fs_info, "invalid key type in iref");
487 ret = -EINVAL;
488 break;
489 }
490 if (ret)
491 break;
492 ptr += btrfs_extent_inline_ref_size(type);
493 }
494 return ret;
495}
496
497static int process_leaf(struct btrfs_root *root,
498 struct btrfs_path *path, u64 *bytenr, u64 *num_bytes,
499 int *tree_block_level)
500{
501 struct btrfs_fs_info *fs_info = root->fs_info;
502 struct extent_buffer *leaf = path->nodes[0];
503 struct btrfs_extent_data_ref *dref;
504 struct btrfs_shared_data_ref *sref;
505 u32 count;
506 int i = 0, ret = 0;
507 struct btrfs_key key;
508 int nritems = btrfs_header_nritems(leaf);
509
510 for (i = 0; i < nritems; i++) {
511 btrfs_item_key_to_cpu(leaf, &key, i);
512 switch (key.type) {
513 case BTRFS_EXTENT_ITEM_KEY:
514 *num_bytes = key.offset;
515 fallthrough;
516 case BTRFS_METADATA_ITEM_KEY:
517 *bytenr = key.objectid;
518 ret = process_extent_item(fs_info, path, &key, i,
519 tree_block_level);
520 break;
521 case BTRFS_TREE_BLOCK_REF_KEY:
522 ret = add_tree_block(fs_info, key.offset, 0,
523 key.objectid, *tree_block_level);
524 break;
525 case BTRFS_SHARED_BLOCK_REF_KEY:
526 ret = add_tree_block(fs_info, 0, key.offset,
527 key.objectid, *tree_block_level);
528 break;
529 case BTRFS_EXTENT_DATA_REF_KEY:
530 dref = btrfs_item_ptr(leaf, i,
531 struct btrfs_extent_data_ref);
532 ret = add_extent_data_ref(fs_info, leaf, dref, *bytenr,
533 *num_bytes);
534 break;
535 case BTRFS_SHARED_DATA_REF_KEY:
536 sref = btrfs_item_ptr(leaf, i,
537 struct btrfs_shared_data_ref);
538 count = btrfs_shared_data_ref_count(leaf, sref);
539 ret = add_shared_data_ref(fs_info, key.offset, count,
540 *bytenr, *num_bytes);
541 break;
542 default:
543 break;
544 }
545 if (ret)
546 break;
547 }
548 return ret;
549}
550
551/* Walk down to the leaf from the given level */
552static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
553 int level, u64 *bytenr, u64 *num_bytes,
554 int *tree_block_level)
555{
556 struct extent_buffer *eb;
557 int ret = 0;
558
559 while (level >= 0) {
560 if (level) {
561 eb = btrfs_read_node_slot(path->nodes[level],
562 path->slots[level]);
563 if (IS_ERR(eb))
564 return PTR_ERR(eb);
565 btrfs_tree_read_lock(eb);
566 path->nodes[level-1] = eb;
567 path->slots[level-1] = 0;
568 path->locks[level-1] = BTRFS_READ_LOCK;
569 } else {
570 ret = process_leaf(root, path, bytenr, num_bytes,
571 tree_block_level);
572 if (ret)
573 break;
574 }
575 level--;
576 }
577 return ret;
578}
579
580/* Walk up to the next node that needs to be processed */
581static int walk_up_tree(struct btrfs_path *path, int *level)
582{
583 int l;
584
585 for (l = 0; l < BTRFS_MAX_LEVEL; l++) {
586 if (!path->nodes[l])
587 continue;
588 if (l) {
589 path->slots[l]++;
590 if (path->slots[l] <
591 btrfs_header_nritems(path->nodes[l])) {
592 *level = l;
593 return 0;
594 }
595 }
596 btrfs_tree_unlock_rw(path->nodes[l], path->locks[l]);
597 free_extent_buffer(path->nodes[l]);
598 path->nodes[l] = NULL;
599 path->slots[l] = 0;
600 path->locks[l] = 0;
601 }
602
603 return 1;
604}
605
606static void dump_ref_action(struct btrfs_fs_info *fs_info,
607 struct ref_action *ra)
608{
609 btrfs_err(fs_info,
610" Ref action %d, root %llu, ref_root %llu, parent %llu, owner %llu, offset %llu, num_refs %llu",
611 ra->action, ra->root, ra->ref.root_objectid, ra->ref.parent,
612 ra->ref.owner, ra->ref.offset, ra->ref.num_refs);
613 __print_stack_trace(fs_info, ra);
614}
615
616/*
617 * Dumps all the information from the block entry to printk, it's going to be
618 * awesome.
619 */
620static void dump_block_entry(struct btrfs_fs_info *fs_info,
621 struct block_entry *be)
622{
623 struct ref_entry *ref;
624 struct root_entry *re;
625 struct ref_action *ra;
626 struct rb_node *n;
627
628 btrfs_err(fs_info,
629"dumping block entry [%llu %llu], num_refs %llu, metadata %d, from disk %d",
630 be->bytenr, be->len, be->num_refs, be->metadata,
631 be->from_disk);
632
633 for (n = rb_first(&be->refs); n; n = rb_next(n)) {
634 ref = rb_entry(n, struct ref_entry, node);
635 btrfs_err(fs_info,
636" ref root %llu, parent %llu, owner %llu, offset %llu, num_refs %llu",
637 ref->root_objectid, ref->parent, ref->owner,
638 ref->offset, ref->num_refs);
639 }
640
641 for (n = rb_first(&be->roots); n; n = rb_next(n)) {
642 re = rb_entry(n, struct root_entry, node);
643 btrfs_err(fs_info, " root entry %llu, num_refs %llu",
644 re->root_objectid, re->num_refs);
645 }
646
647 list_for_each_entry(ra, &be->actions, list)
648 dump_ref_action(fs_info, ra);
649}
650
651/*
652 * btrfs_ref_tree_mod: called when we modify a ref for a bytenr
653 *
654 * This will add an action item to the given bytenr and do sanity checks to make
655 * sure we haven't messed something up. If we are making a new allocation and
656 * this block entry has history we will delete all previous actions as long as
657 * our sanity checks pass as they are no longer needed.
658 */
659int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info,
660 struct btrfs_ref *generic_ref)
661{
662 struct ref_entry *ref = NULL, *exist;
663 struct ref_action *ra = NULL;
664 struct block_entry *be = NULL;
665 struct root_entry *re = NULL;
666 int action = generic_ref->action;
667 int ret = 0;
668 bool metadata;
669 u64 bytenr = generic_ref->bytenr;
670 u64 num_bytes = generic_ref->len;
671 u64 parent = generic_ref->parent;
672 u64 ref_root = 0;
673 u64 owner = 0;
674 u64 offset = 0;
675
676 if (!btrfs_test_opt(fs_info, REF_VERIFY))
677 return 0;
678
679 if (generic_ref->type == BTRFS_REF_METADATA) {
680 if (!parent)
681 ref_root = generic_ref->tree_ref.root;
682 owner = generic_ref->tree_ref.level;
683 } else if (!parent) {
684 ref_root = generic_ref->data_ref.ref_root;
685 owner = generic_ref->data_ref.ino;
686 offset = generic_ref->data_ref.offset;
687 }
688 metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
689
690 ref = kzalloc(sizeof(struct ref_entry), GFP_NOFS);
691 ra = kmalloc(sizeof(struct ref_action), GFP_NOFS);
692 if (!ra || !ref) {
693 kfree(ref);
694 kfree(ra);
695 ret = -ENOMEM;
696 goto out;
697 }
698
699 ref->parent = parent;
700 ref->owner = owner;
701 ref->root_objectid = ref_root;
702 ref->offset = offset;
703 ref->num_refs = (action == BTRFS_DROP_DELAYED_REF) ? -1 : 1;
704
705 memcpy(&ra->ref, ref, sizeof(struct ref_entry));
706 /*
707 * Save the extra info from the delayed ref in the ref action to make it
708 * easier to figure out what is happening. The real ref's we add to the
709 * ref tree need to reflect what we save on disk so it matches any
710 * on-disk refs we pre-loaded.
711 */
712 ra->ref.owner = owner;
713 ra->ref.offset = offset;
714 ra->ref.root_objectid = ref_root;
715 __save_stack_trace(ra);
716
717 INIT_LIST_HEAD(&ra->list);
718 ra->action = action;
719 ra->root = generic_ref->real_root;
720
721 /*
722 * This is an allocation, preallocate the block_entry in case we haven't
723 * used it before.
724 */
725 ret = -EINVAL;
726 if (action == BTRFS_ADD_DELAYED_EXTENT) {
727 /*
728 * For subvol_create we'll just pass in whatever the parent root
729 * is and the new root objectid, so let's not treat the passed
730 * in root as if it really has a ref for this bytenr.
731 */
732 be = add_block_entry(fs_info, bytenr, num_bytes, ref_root);
733 if (IS_ERR(be)) {
734 kfree(ref);
735 kfree(ra);
736 ret = PTR_ERR(be);
737 goto out;
738 }
739 be->num_refs++;
740 if (metadata)
741 be->metadata = 1;
742
743 if (be->num_refs != 1) {
744 btrfs_err(fs_info,
745 "re-allocated a block that still has references to it!");
746 dump_block_entry(fs_info, be);
747 dump_ref_action(fs_info, ra);
748 kfree(ref);
749 kfree(ra);
750 goto out_unlock;
751 }
752
753 while (!list_empty(&be->actions)) {
754 struct ref_action *tmp;
755
756 tmp = list_first_entry(&be->actions, struct ref_action,
757 list);
758 list_del(&tmp->list);
759 kfree(tmp);
760 }
761 } else {
762 struct root_entry *tmp;
763
764 if (!parent) {
765 re = kmalloc(sizeof(struct root_entry), GFP_NOFS);
766 if (!re) {
767 kfree(ref);
768 kfree(ra);
769 ret = -ENOMEM;
770 goto out;
771 }
772 /*
773 * This is the root that is modifying us, so it's the
774 * one we want to lookup below when we modify the
775 * re->num_refs.
776 */
777 ref_root = generic_ref->real_root;
778 re->root_objectid = generic_ref->real_root;
779 re->num_refs = 0;
780 }
781
782 spin_lock(&fs_info->ref_verify_lock);
783 be = lookup_block_entry(&fs_info->block_tree, bytenr);
784 if (!be) {
785 btrfs_err(fs_info,
786"trying to do action %d to bytenr %llu num_bytes %llu but there is no existing entry!",
787 action, bytenr, num_bytes);
788 dump_ref_action(fs_info, ra);
789 kfree(ref);
790 kfree(ra);
791 goto out_unlock;
792 } else if (be->num_refs == 0) {
793 btrfs_err(fs_info,
794 "trying to do action %d for a bytenr that has 0 total references",
795 action);
796 dump_block_entry(fs_info, be);
797 dump_ref_action(fs_info, ra);
798 kfree(ref);
799 kfree(ra);
800 goto out_unlock;
801 }
802
803 if (!parent) {
804 tmp = insert_root_entry(&be->roots, re);
805 if (tmp) {
806 kfree(re);
807 re = tmp;
808 }
809 }
810 }
811
812 exist = insert_ref_entry(&be->refs, ref);
813 if (exist) {
814 if (action == BTRFS_DROP_DELAYED_REF) {
815 if (exist->num_refs == 0) {
816 btrfs_err(fs_info,
817"dropping a ref for a existing root that doesn't have a ref on the block");
818 dump_block_entry(fs_info, be);
819 dump_ref_action(fs_info, ra);
820 kfree(ref);
821 kfree(ra);
822 goto out_unlock;
823 }
824 exist->num_refs--;
825 if (exist->num_refs == 0) {
826 rb_erase(&exist->node, &be->refs);
827 kfree(exist);
828 }
829 } else if (!be->metadata) {
830 exist->num_refs++;
831 } else {
832 btrfs_err(fs_info,
833"attempting to add another ref for an existing ref on a tree block");
834 dump_block_entry(fs_info, be);
835 dump_ref_action(fs_info, ra);
836 kfree(ref);
837 kfree(ra);
838 goto out_unlock;
839 }
840 kfree(ref);
841 } else {
842 if (action == BTRFS_DROP_DELAYED_REF) {
843 btrfs_err(fs_info,
844"dropping a ref for a root that doesn't have a ref on the block");
845 dump_block_entry(fs_info, be);
846 dump_ref_action(fs_info, ra);
847 kfree(ref);
848 kfree(ra);
849 goto out_unlock;
850 }
851 }
852
853 if (!parent && !re) {
854 re = lookup_root_entry(&be->roots, ref_root);
855 if (!re) {
856 /*
857 * This shouldn't happen because we will add our re
858 * above when we lookup the be with !parent, but just in
859 * case catch this case so we don't panic because I
860 * didn't think of some other corner case.
861 */
862 btrfs_err(fs_info, "failed to find root %llu for %llu",
863 generic_ref->real_root, be->bytenr);
864 dump_block_entry(fs_info, be);
865 dump_ref_action(fs_info, ra);
866 kfree(ra);
867 goto out_unlock;
868 }
869 }
870 if (action == BTRFS_DROP_DELAYED_REF) {
871 if (re)
872 re->num_refs--;
873 be->num_refs--;
874 } else if (action == BTRFS_ADD_DELAYED_REF) {
875 be->num_refs++;
876 if (re)
877 re->num_refs++;
878 }
879 list_add_tail(&ra->list, &be->actions);
880 ret = 0;
881out_unlock:
882 spin_unlock(&fs_info->ref_verify_lock);
883out:
884 if (ret)
885 btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
886 return ret;
887}
888
889/* Free up the ref cache */
890void btrfs_free_ref_cache(struct btrfs_fs_info *fs_info)
891{
892 struct block_entry *be;
893 struct rb_node *n;
894
895 if (!btrfs_test_opt(fs_info, REF_VERIFY))
896 return;
897
898 spin_lock(&fs_info->ref_verify_lock);
899 while ((n = rb_first(&fs_info->block_tree))) {
900 be = rb_entry(n, struct block_entry, node);
901 rb_erase(&be->node, &fs_info->block_tree);
902 free_block_entry(be);
903 cond_resched_lock(&fs_info->ref_verify_lock);
904 }
905 spin_unlock(&fs_info->ref_verify_lock);
906}
907
908void btrfs_free_ref_tree_range(struct btrfs_fs_info *fs_info, u64 start,
909 u64 len)
910{
911 struct block_entry *be = NULL, *entry;
912 struct rb_node *n;
913
914 if (!btrfs_test_opt(fs_info, REF_VERIFY))
915 return;
916
917 spin_lock(&fs_info->ref_verify_lock);
918 n = fs_info->block_tree.rb_node;
919 while (n) {
920 entry = rb_entry(n, struct block_entry, node);
921 if (entry->bytenr < start) {
922 n = n->rb_right;
923 } else if (entry->bytenr > start) {
924 n = n->rb_left;
925 } else {
926 be = entry;
927 break;
928 }
929 /* We want to get as close to start as possible */
930 if (be == NULL ||
931 (entry->bytenr < start && be->bytenr > start) ||
932 (entry->bytenr < start && entry->bytenr > be->bytenr))
933 be = entry;
934 }
935
936 /*
937 * Could have an empty block group, maybe have something to check for
938 * this case to verify we were actually empty?
939 */
940 if (!be) {
941 spin_unlock(&fs_info->ref_verify_lock);
942 return;
943 }
944
945 n = &be->node;
946 while (n) {
947 be = rb_entry(n, struct block_entry, node);
948 n = rb_next(n);
949 if (be->bytenr < start && be->bytenr + be->len > start) {
950 btrfs_err(fs_info,
951 "block entry overlaps a block group [%llu,%llu]!",
952 start, len);
953 dump_block_entry(fs_info, be);
954 continue;
955 }
956 if (be->bytenr < start)
957 continue;
958 if (be->bytenr >= start + len)
959 break;
960 if (be->bytenr + be->len > start + len) {
961 btrfs_err(fs_info,
962 "block entry overlaps a block group [%llu,%llu]!",
963 start, len);
964 dump_block_entry(fs_info, be);
965 }
966 rb_erase(&be->node, &fs_info->block_tree);
967 free_block_entry(be);
968 }
969 spin_unlock(&fs_info->ref_verify_lock);
970}
971
972/* Walk down all roots and build the ref tree, meant to be called at mount */
973int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
974{
975 struct btrfs_path *path;
976 struct extent_buffer *eb;
977 int tree_block_level = 0;
978 u64 bytenr = 0, num_bytes = 0;
979 int ret, level;
980
981 if (!btrfs_test_opt(fs_info, REF_VERIFY))
982 return 0;
983
984 path = btrfs_alloc_path();
985 if (!path)
986 return -ENOMEM;
987
988 eb = btrfs_read_lock_root_node(fs_info->extent_root);
989 level = btrfs_header_level(eb);
990 path->nodes[level] = eb;
991 path->slots[level] = 0;
992 path->locks[level] = BTRFS_READ_LOCK;
993
994 while (1) {
995 /*
996 * We have to keep track of the bytenr/num_bytes we last hit
997 * because we could have run out of space for an inline ref, and
998 * would have had to added a ref key item which may appear on a
999 * different leaf from the original extent item.
1000 */
1001 ret = walk_down_tree(fs_info->extent_root, path, level,
1002 &bytenr, &num_bytes, &tree_block_level);
1003 if (ret)
1004 break;
1005 ret = walk_up_tree(path, &level);
1006 if (ret < 0)
1007 break;
1008 if (ret > 0) {
1009 ret = 0;
1010 break;
1011 }
1012 }
1013 if (ret) {
1014 btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
1015 btrfs_free_ref_cache(fs_info);
1016 }
1017 btrfs_free_path(path);
1018 return ret;
1019}