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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 "messages.h"
9#include "ctree.h"
10#include "disk-io.h"
11#include "locking.h"
12#include "delayed-ref.h"
13#include "ref-verify.h"
14#include "fs.h"
15#include "accessors.h"
16
17/*
18 * Used to keep track the roots and number of refs each root has for a given
19 * bytenr. This just tracks the number of direct references, no shared
20 * references.
21 */
22struct root_entry {
23 u64 root_objectid;
24 u64 num_refs;
25 struct rb_node node;
26};
27
28/*
29 * These are meant to represent what should exist in the extent tree, these can
30 * be used to verify the extent tree is consistent as these should all match
31 * what the extent tree says.
32 */
33struct ref_entry {
34 u64 root_objectid;
35 u64 parent;
36 u64 owner;
37 u64 offset;
38 u64 num_refs;
39 struct rb_node node;
40};
41
42#define MAX_TRACE 16
43
44/*
45 * Whenever we add/remove a reference we record the action. The action maps
46 * back to the delayed ref action. We hold the ref we are changing in the
47 * action so we can account for the history properly, and we record the root we
48 * were called with since it could be different from ref_root. We also store
49 * stack traces because that's how I roll.
50 */
51struct ref_action {
52 int action;
53 u64 root;
54 struct ref_entry ref;
55 struct list_head list;
56 unsigned long trace[MAX_TRACE];
57 unsigned int trace_len;
58};
59
60/*
61 * One of these for every block we reference, it holds the roots and references
62 * to it as well as all of the ref actions that have occurred to it. We never
63 * free it until we unmount the file system in order to make sure re-allocations
64 * are happening properly.
65 */
66struct block_entry {
67 u64 bytenr;
68 u64 len;
69 u64 num_refs;
70 int metadata;
71 int from_disk;
72 struct rb_root roots;
73 struct rb_root refs;
74 struct rb_node node;
75 struct list_head actions;
76};
77
78static struct block_entry *insert_block_entry(struct rb_root *root,
79 struct block_entry *be)
80{
81 struct rb_node **p = &root->rb_node;
82 struct rb_node *parent_node = NULL;
83 struct block_entry *entry;
84
85 while (*p) {
86 parent_node = *p;
87 entry = rb_entry(parent_node, struct block_entry, node);
88 if (entry->bytenr > be->bytenr)
89 p = &(*p)->rb_left;
90 else if (entry->bytenr < be->bytenr)
91 p = &(*p)->rb_right;
92 else
93 return entry;
94 }
95
96 rb_link_node(&be->node, parent_node, p);
97 rb_insert_color(&be->node, root);
98 return NULL;
99}
100
101static struct block_entry *lookup_block_entry(struct rb_root *root, u64 bytenr)
102{
103 struct rb_node *n;
104 struct block_entry *entry = NULL;
105
106 n = root->rb_node;
107 while (n) {
108 entry = rb_entry(n, struct block_entry, node);
109 if (entry->bytenr < bytenr)
110 n = n->rb_right;
111 else if (entry->bytenr > bytenr)
112 n = n->rb_left;
113 else
114 return entry;
115 }
116 return NULL;
117}
118
119static struct root_entry *insert_root_entry(struct rb_root *root,
120 struct root_entry *re)
121{
122 struct rb_node **p = &root->rb_node;
123 struct rb_node *parent_node = NULL;
124 struct root_entry *entry;
125
126 while (*p) {
127 parent_node = *p;
128 entry = rb_entry(parent_node, struct root_entry, node);
129 if (entry->root_objectid > re->root_objectid)
130 p = &(*p)->rb_left;
131 else if (entry->root_objectid < re->root_objectid)
132 p = &(*p)->rb_right;
133 else
134 return entry;
135 }
136
137 rb_link_node(&re->node, parent_node, p);
138 rb_insert_color(&re->node, root);
139 return NULL;
140
141}
142
143static int comp_refs(struct ref_entry *ref1, struct ref_entry *ref2)
144{
145 if (ref1->root_objectid < ref2->root_objectid)
146 return -1;
147 if (ref1->root_objectid > ref2->root_objectid)
148 return 1;
149 if (ref1->parent < ref2->parent)
150 return -1;
151 if (ref1->parent > ref2->parent)
152 return 1;
153 if (ref1->owner < ref2->owner)
154 return -1;
155 if (ref1->owner > ref2->owner)
156 return 1;
157 if (ref1->offset < ref2->offset)
158 return -1;
159 if (ref1->offset > ref2->offset)
160 return 1;
161 return 0;
162}
163
164static struct ref_entry *insert_ref_entry(struct rb_root *root,
165 struct ref_entry *ref)
166{
167 struct rb_node **p = &root->rb_node;
168 struct rb_node *parent_node = NULL;
169 struct ref_entry *entry;
170 int cmp;
171
172 while (*p) {
173 parent_node = *p;
174 entry = rb_entry(parent_node, struct ref_entry, node);
175 cmp = comp_refs(entry, ref);
176 if (cmp > 0)
177 p = &(*p)->rb_left;
178 else if (cmp < 0)
179 p = &(*p)->rb_right;
180 else
181 return entry;
182 }
183
184 rb_link_node(&ref->node, parent_node, p);
185 rb_insert_color(&ref->node, root);
186 return NULL;
187
188}
189
190static struct root_entry *lookup_root_entry(struct rb_root *root, u64 objectid)
191{
192 struct rb_node *n;
193 struct root_entry *entry = NULL;
194
195 n = root->rb_node;
196 while (n) {
197 entry = rb_entry(n, struct root_entry, node);
198 if (entry->root_objectid < objectid)
199 n = n->rb_right;
200 else if (entry->root_objectid > objectid)
201 n = n->rb_left;
202 else
203 return entry;
204 }
205 return NULL;
206}
207
208#ifdef CONFIG_STACKTRACE
209static void __save_stack_trace(struct ref_action *ra)
210{
211 ra->trace_len = stack_trace_save(ra->trace, MAX_TRACE, 2);
212}
213
214static void __print_stack_trace(struct btrfs_fs_info *fs_info,
215 struct ref_action *ra)
216{
217 if (ra->trace_len == 0) {
218 btrfs_err(fs_info, " ref-verify: no stacktrace");
219 return;
220 }
221 stack_trace_print(ra->trace, ra->trace_len, 2);
222}
223#else
224static inline void __save_stack_trace(struct ref_action *ra)
225{
226}
227
228static inline void __print_stack_trace(struct btrfs_fs_info *fs_info,
229 struct ref_action *ra)
230{
231 btrfs_err(fs_info, " ref-verify: no stacktrace support");
232}
233#endif
234
235static void free_block_entry(struct block_entry *be)
236{
237 struct root_entry *re;
238 struct ref_entry *ref;
239 struct ref_action *ra;
240 struct rb_node *n;
241
242 while ((n = rb_first(&be->roots))) {
243 re = rb_entry(n, struct root_entry, node);
244 rb_erase(&re->node, &be->roots);
245 kfree(re);
246 }
247
248 while((n = rb_first(&be->refs))) {
249 ref = rb_entry(n, struct ref_entry, node);
250 rb_erase(&ref->node, &be->refs);
251 kfree(ref);
252 }
253
254 while (!list_empty(&be->actions)) {
255 ra = list_first_entry(&be->actions, struct ref_action,
256 list);
257 list_del(&ra->list);
258 kfree(ra);
259 }
260 kfree(be);
261}
262
263static struct block_entry *add_block_entry(struct btrfs_fs_info *fs_info,
264 u64 bytenr, u64 len,
265 u64 root_objectid)
266{
267 struct block_entry *be = NULL, *exist;
268 struct root_entry *re = NULL;
269
270 re = kzalloc(sizeof(struct root_entry), GFP_NOFS);
271 be = kzalloc(sizeof(struct block_entry), GFP_NOFS);
272 if (!be || !re) {
273 kfree(re);
274 kfree(be);
275 return ERR_PTR(-ENOMEM);
276 }
277 be->bytenr = bytenr;
278 be->len = len;
279
280 re->root_objectid = root_objectid;
281 re->num_refs = 0;
282
283 spin_lock(&fs_info->ref_verify_lock);
284 exist = insert_block_entry(&fs_info->block_tree, be);
285 if (exist) {
286 if (root_objectid) {
287 struct root_entry *exist_re;
288
289 exist_re = insert_root_entry(&exist->roots, re);
290 if (exist_re)
291 kfree(re);
292 } else {
293 kfree(re);
294 }
295 kfree(be);
296 return exist;
297 }
298
299 be->num_refs = 0;
300 be->metadata = 0;
301 be->from_disk = 0;
302 be->roots = RB_ROOT;
303 be->refs = RB_ROOT;
304 INIT_LIST_HEAD(&be->actions);
305 if (root_objectid)
306 insert_root_entry(&be->roots, re);
307 else
308 kfree(re);
309 return be;
310}
311
312static int add_tree_block(struct btrfs_fs_info *fs_info, u64 ref_root,
313 u64 parent, u64 bytenr, int level)
314{
315 struct block_entry *be;
316 struct root_entry *re;
317 struct ref_entry *ref = NULL, *exist;
318
319 ref = kmalloc(sizeof(struct ref_entry), GFP_NOFS);
320 if (!ref)
321 return -ENOMEM;
322
323 if (parent)
324 ref->root_objectid = 0;
325 else
326 ref->root_objectid = ref_root;
327 ref->parent = parent;
328 ref->owner = level;
329 ref->offset = 0;
330 ref->num_refs = 1;
331
332 be = add_block_entry(fs_info, bytenr, fs_info->nodesize, ref_root);
333 if (IS_ERR(be)) {
334 kfree(ref);
335 return PTR_ERR(be);
336 }
337 be->num_refs++;
338 be->from_disk = 1;
339 be->metadata = 1;
340
341 if (!parent) {
342 ASSERT(ref_root);
343 re = lookup_root_entry(&be->roots, ref_root);
344 ASSERT(re);
345 re->num_refs++;
346 }
347 exist = insert_ref_entry(&be->refs, ref);
348 if (exist) {
349 exist->num_refs++;
350 kfree(ref);
351 }
352 spin_unlock(&fs_info->ref_verify_lock);
353
354 return 0;
355}
356
357static int add_shared_data_ref(struct btrfs_fs_info *fs_info,
358 u64 parent, u32 num_refs, u64 bytenr,
359 u64 num_bytes)
360{
361 struct block_entry *be;
362 struct ref_entry *ref;
363
364 ref = kzalloc(sizeof(struct ref_entry), GFP_NOFS);
365 if (!ref)
366 return -ENOMEM;
367 be = add_block_entry(fs_info, bytenr, num_bytes, 0);
368 if (IS_ERR(be)) {
369 kfree(ref);
370 return PTR_ERR(be);
371 }
372 be->num_refs += num_refs;
373
374 ref->parent = parent;
375 ref->num_refs = num_refs;
376 if (insert_ref_entry(&be->refs, ref)) {
377 spin_unlock(&fs_info->ref_verify_lock);
378 btrfs_err(fs_info, "existing shared ref when reading from disk?");
379 kfree(ref);
380 return -EINVAL;
381 }
382 spin_unlock(&fs_info->ref_verify_lock);
383 return 0;
384}
385
386static int add_extent_data_ref(struct btrfs_fs_info *fs_info,
387 struct extent_buffer *leaf,
388 struct btrfs_extent_data_ref *dref,
389 u64 bytenr, u64 num_bytes)
390{
391 struct block_entry *be;
392 struct ref_entry *ref;
393 struct root_entry *re;
394 u64 ref_root = btrfs_extent_data_ref_root(leaf, dref);
395 u64 owner = btrfs_extent_data_ref_objectid(leaf, dref);
396 u64 offset = btrfs_extent_data_ref_offset(leaf, dref);
397 u32 num_refs = btrfs_extent_data_ref_count(leaf, dref);
398
399 ref = kzalloc(sizeof(struct ref_entry), GFP_NOFS);
400 if (!ref)
401 return -ENOMEM;
402 be = add_block_entry(fs_info, bytenr, num_bytes, ref_root);
403 if (IS_ERR(be)) {
404 kfree(ref);
405 return PTR_ERR(be);
406 }
407 be->num_refs += num_refs;
408
409 ref->parent = 0;
410 ref->owner = owner;
411 ref->root_objectid = ref_root;
412 ref->offset = offset;
413 ref->num_refs = num_refs;
414 if (insert_ref_entry(&be->refs, ref)) {
415 spin_unlock(&fs_info->ref_verify_lock);
416 btrfs_err(fs_info, "existing ref when reading from disk?");
417 kfree(ref);
418 return -EINVAL;
419 }
420
421 re = lookup_root_entry(&be->roots, ref_root);
422 if (!re) {
423 spin_unlock(&fs_info->ref_verify_lock);
424 btrfs_err(fs_info, "missing root in new block entry?");
425 return -EINVAL;
426 }
427 re->num_refs += num_refs;
428 spin_unlock(&fs_info->ref_verify_lock);
429 return 0;
430}
431
432static int process_extent_item(struct btrfs_fs_info *fs_info,
433 struct btrfs_path *path, struct btrfs_key *key,
434 int slot, int *tree_block_level)
435{
436 struct btrfs_extent_item *ei;
437 struct btrfs_extent_inline_ref *iref;
438 struct btrfs_extent_data_ref *dref;
439 struct btrfs_shared_data_ref *sref;
440 struct extent_buffer *leaf = path->nodes[0];
441 u32 item_size = btrfs_item_size(leaf, slot);
442 unsigned long end, ptr;
443 u64 offset, flags, count;
444 int type, ret;
445
446 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
447 flags = btrfs_extent_flags(leaf, ei);
448
449 if ((key->type == BTRFS_EXTENT_ITEM_KEY) &&
450 flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
451 struct btrfs_tree_block_info *info;
452
453 info = (struct btrfs_tree_block_info *)(ei + 1);
454 *tree_block_level = btrfs_tree_block_level(leaf, info);
455 iref = (struct btrfs_extent_inline_ref *)(info + 1);
456 } else {
457 if (key->type == BTRFS_METADATA_ITEM_KEY)
458 *tree_block_level = key->offset;
459 iref = (struct btrfs_extent_inline_ref *)(ei + 1);
460 }
461
462 ptr = (unsigned long)iref;
463 end = (unsigned long)ei + item_size;
464 while (ptr < end) {
465 iref = (struct btrfs_extent_inline_ref *)ptr;
466 type = btrfs_extent_inline_ref_type(leaf, iref);
467 offset = btrfs_extent_inline_ref_offset(leaf, iref);
468 switch (type) {
469 case BTRFS_TREE_BLOCK_REF_KEY:
470 ret = add_tree_block(fs_info, offset, 0, key->objectid,
471 *tree_block_level);
472 break;
473 case BTRFS_SHARED_BLOCK_REF_KEY:
474 ret = add_tree_block(fs_info, 0, offset, key->objectid,
475 *tree_block_level);
476 break;
477 case BTRFS_EXTENT_DATA_REF_KEY:
478 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
479 ret = add_extent_data_ref(fs_info, leaf, dref,
480 key->objectid, key->offset);
481 break;
482 case BTRFS_SHARED_DATA_REF_KEY:
483 sref = (struct btrfs_shared_data_ref *)(iref + 1);
484 count = btrfs_shared_data_ref_count(leaf, sref);
485 ret = add_shared_data_ref(fs_info, offset, count,
486 key->objectid, key->offset);
487 break;
488 case BTRFS_EXTENT_OWNER_REF_KEY:
489 WARN_ON(!btrfs_fs_incompat(fs_info, SIMPLE_QUOTA));
490 break;
491 default:
492 btrfs_err(fs_info, "invalid key type in iref");
493 ret = -EINVAL;
494 break;
495 }
496 if (ret)
497 break;
498 ptr += btrfs_extent_inline_ref_size(type);
499 }
500 return ret;
501}
502
503static int process_leaf(struct btrfs_root *root,
504 struct btrfs_path *path, u64 *bytenr, u64 *num_bytes,
505 int *tree_block_level)
506{
507 struct btrfs_fs_info *fs_info = root->fs_info;
508 struct extent_buffer *leaf = path->nodes[0];
509 struct btrfs_extent_data_ref *dref;
510 struct btrfs_shared_data_ref *sref;
511 u32 count;
512 int i = 0, ret = 0;
513 struct btrfs_key key;
514 int nritems = btrfs_header_nritems(leaf);
515
516 for (i = 0; i < nritems; i++) {
517 btrfs_item_key_to_cpu(leaf, &key, i);
518 switch (key.type) {
519 case BTRFS_EXTENT_ITEM_KEY:
520 *num_bytes = key.offset;
521 fallthrough;
522 case BTRFS_METADATA_ITEM_KEY:
523 *bytenr = key.objectid;
524 ret = process_extent_item(fs_info, path, &key, i,
525 tree_block_level);
526 break;
527 case BTRFS_TREE_BLOCK_REF_KEY:
528 ret = add_tree_block(fs_info, key.offset, 0,
529 key.objectid, *tree_block_level);
530 break;
531 case BTRFS_SHARED_BLOCK_REF_KEY:
532 ret = add_tree_block(fs_info, 0, key.offset,
533 key.objectid, *tree_block_level);
534 break;
535 case BTRFS_EXTENT_DATA_REF_KEY:
536 dref = btrfs_item_ptr(leaf, i,
537 struct btrfs_extent_data_ref);
538 ret = add_extent_data_ref(fs_info, leaf, dref, *bytenr,
539 *num_bytes);
540 break;
541 case BTRFS_SHARED_DATA_REF_KEY:
542 sref = btrfs_item_ptr(leaf, i,
543 struct btrfs_shared_data_ref);
544 count = btrfs_shared_data_ref_count(leaf, sref);
545 ret = add_shared_data_ref(fs_info, key.offset, count,
546 *bytenr, *num_bytes);
547 break;
548 default:
549 break;
550 }
551 if (ret)
552 break;
553 }
554 return ret;
555}
556
557/* Walk down to the leaf from the given level */
558static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
559 int level, u64 *bytenr, u64 *num_bytes,
560 int *tree_block_level)
561{
562 struct extent_buffer *eb;
563 int ret = 0;
564
565 while (level >= 0) {
566 if (level) {
567 eb = btrfs_read_node_slot(path->nodes[level],
568 path->slots[level]);
569 if (IS_ERR(eb))
570 return PTR_ERR(eb);
571 btrfs_tree_read_lock(eb);
572 path->nodes[level-1] = eb;
573 path->slots[level-1] = 0;
574 path->locks[level-1] = BTRFS_READ_LOCK;
575 } else {
576 ret = process_leaf(root, path, bytenr, num_bytes,
577 tree_block_level);
578 if (ret)
579 break;
580 }
581 level--;
582 }
583 return ret;
584}
585
586/* Walk up to the next node that needs to be processed */
587static int walk_up_tree(struct btrfs_path *path, int *level)
588{
589 int l;
590
591 for (l = 0; l < BTRFS_MAX_LEVEL; l++) {
592 if (!path->nodes[l])
593 continue;
594 if (l) {
595 path->slots[l]++;
596 if (path->slots[l] <
597 btrfs_header_nritems(path->nodes[l])) {
598 *level = l;
599 return 0;
600 }
601 }
602 btrfs_tree_unlock_rw(path->nodes[l], path->locks[l]);
603 free_extent_buffer(path->nodes[l]);
604 path->nodes[l] = NULL;
605 path->slots[l] = 0;
606 path->locks[l] = 0;
607 }
608
609 return 1;
610}
611
612static void dump_ref_action(struct btrfs_fs_info *fs_info,
613 struct ref_action *ra)
614{
615 btrfs_err(fs_info,
616" Ref action %d, root %llu, ref_root %llu, parent %llu, owner %llu, offset %llu, num_refs %llu",
617 ra->action, ra->root, ra->ref.root_objectid, ra->ref.parent,
618 ra->ref.owner, ra->ref.offset, ra->ref.num_refs);
619 __print_stack_trace(fs_info, ra);
620}
621
622/*
623 * Dumps all the information from the block entry to printk, it's going to be
624 * awesome.
625 */
626static void dump_block_entry(struct btrfs_fs_info *fs_info,
627 struct block_entry *be)
628{
629 struct ref_entry *ref;
630 struct root_entry *re;
631 struct ref_action *ra;
632 struct rb_node *n;
633
634 btrfs_err(fs_info,
635"dumping block entry [%llu %llu], num_refs %llu, metadata %d, from disk %d",
636 be->bytenr, be->len, be->num_refs, be->metadata,
637 be->from_disk);
638
639 for (n = rb_first(&be->refs); n; n = rb_next(n)) {
640 ref = rb_entry(n, struct ref_entry, node);
641 btrfs_err(fs_info,
642" ref root %llu, parent %llu, owner %llu, offset %llu, num_refs %llu",
643 ref->root_objectid, ref->parent, ref->owner,
644 ref->offset, ref->num_refs);
645 }
646
647 for (n = rb_first(&be->roots); n; n = rb_next(n)) {
648 re = rb_entry(n, struct root_entry, node);
649 btrfs_err(fs_info, " root entry %llu, num_refs %llu",
650 re->root_objectid, re->num_refs);
651 }
652
653 list_for_each_entry(ra, &be->actions, list)
654 dump_ref_action(fs_info, ra);
655}
656
657/*
658 * Called when we modify a ref for a bytenr.
659 *
660 * This will add an action item to the given bytenr and do sanity checks to make
661 * sure we haven't messed something up. If we are making a new allocation and
662 * this block entry has history we will delete all previous actions as long as
663 * our sanity checks pass as they are no longer needed.
664 */
665int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info,
666 struct btrfs_ref *generic_ref)
667{
668 struct ref_entry *ref = NULL, *exist;
669 struct ref_action *ra = NULL;
670 struct block_entry *be = NULL;
671 struct root_entry *re = NULL;
672 int action = generic_ref->action;
673 int ret = 0;
674 bool metadata;
675 u64 bytenr = generic_ref->bytenr;
676 u64 num_bytes = generic_ref->len;
677 u64 parent = generic_ref->parent;
678 u64 ref_root = 0;
679 u64 owner = 0;
680 u64 offset = 0;
681
682 if (!btrfs_test_opt(fs_info, REF_VERIFY))
683 return 0;
684
685 if (generic_ref->type == BTRFS_REF_METADATA) {
686 if (!parent)
687 ref_root = generic_ref->tree_ref.ref_root;
688 owner = generic_ref->tree_ref.level;
689 } else if (!parent) {
690 ref_root = generic_ref->data_ref.ref_root;
691 owner = generic_ref->data_ref.ino;
692 offset = generic_ref->data_ref.offset;
693 }
694 metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
695
696 ref = kzalloc(sizeof(struct ref_entry), GFP_NOFS);
697 ra = kmalloc(sizeof(struct ref_action), GFP_NOFS);
698 if (!ra || !ref) {
699 kfree(ref);
700 kfree(ra);
701 ret = -ENOMEM;
702 goto out;
703 }
704
705 ref->parent = parent;
706 ref->owner = owner;
707 ref->root_objectid = ref_root;
708 ref->offset = offset;
709 ref->num_refs = (action == BTRFS_DROP_DELAYED_REF) ? -1 : 1;
710
711 memcpy(&ra->ref, ref, sizeof(struct ref_entry));
712 /*
713 * Save the extra info from the delayed ref in the ref action to make it
714 * easier to figure out what is happening. The real ref's we add to the
715 * ref tree need to reflect what we save on disk so it matches any
716 * on-disk refs we pre-loaded.
717 */
718 ra->ref.owner = owner;
719 ra->ref.offset = offset;
720 ra->ref.root_objectid = ref_root;
721 __save_stack_trace(ra);
722
723 INIT_LIST_HEAD(&ra->list);
724 ra->action = action;
725 ra->root = generic_ref->real_root;
726
727 /*
728 * This is an allocation, preallocate the block_entry in case we haven't
729 * used it before.
730 */
731 ret = -EINVAL;
732 if (action == BTRFS_ADD_DELAYED_EXTENT) {
733 /*
734 * For subvol_create we'll just pass in whatever the parent root
735 * is and the new root objectid, so let's not treat the passed
736 * in root as if it really has a ref for this bytenr.
737 */
738 be = add_block_entry(fs_info, bytenr, num_bytes, ref_root);
739 if (IS_ERR(be)) {
740 kfree(ref);
741 kfree(ra);
742 ret = PTR_ERR(be);
743 goto out;
744 }
745 be->num_refs++;
746 if (metadata)
747 be->metadata = 1;
748
749 if (be->num_refs != 1) {
750 btrfs_err(fs_info,
751 "re-allocated a block that still has references to it!");
752 dump_block_entry(fs_info, be);
753 dump_ref_action(fs_info, ra);
754 kfree(ref);
755 kfree(ra);
756 goto out_unlock;
757 }
758
759 while (!list_empty(&be->actions)) {
760 struct ref_action *tmp;
761
762 tmp = list_first_entry(&be->actions, struct ref_action,
763 list);
764 list_del(&tmp->list);
765 kfree(tmp);
766 }
767 } else {
768 struct root_entry *tmp;
769
770 if (!parent) {
771 re = kmalloc(sizeof(struct root_entry), GFP_NOFS);
772 if (!re) {
773 kfree(ref);
774 kfree(ra);
775 ret = -ENOMEM;
776 goto out;
777 }
778 /*
779 * This is the root that is modifying us, so it's the
780 * one we want to lookup below when we modify the
781 * re->num_refs.
782 */
783 ref_root = generic_ref->real_root;
784 re->root_objectid = generic_ref->real_root;
785 re->num_refs = 0;
786 }
787
788 spin_lock(&fs_info->ref_verify_lock);
789 be = lookup_block_entry(&fs_info->block_tree, bytenr);
790 if (!be) {
791 btrfs_err(fs_info,
792"trying to do action %d to bytenr %llu num_bytes %llu but there is no existing entry!",
793 action, bytenr, num_bytes);
794 dump_ref_action(fs_info, ra);
795 kfree(ref);
796 kfree(ra);
797 kfree(re);
798 goto out_unlock;
799 } else if (be->num_refs == 0) {
800 btrfs_err(fs_info,
801 "trying to do action %d for a bytenr that has 0 total references",
802 action);
803 dump_block_entry(fs_info, be);
804 dump_ref_action(fs_info, ra);
805 kfree(ref);
806 kfree(ra);
807 kfree(re);
808 goto out_unlock;
809 }
810
811 if (!parent) {
812 tmp = insert_root_entry(&be->roots, re);
813 if (tmp) {
814 kfree(re);
815 re = tmp;
816 }
817 }
818 }
819
820 exist = insert_ref_entry(&be->refs, ref);
821 if (exist) {
822 if (action == BTRFS_DROP_DELAYED_REF) {
823 if (exist->num_refs == 0) {
824 btrfs_err(fs_info,
825"dropping a ref for a existing root that doesn't have a ref on the block");
826 dump_block_entry(fs_info, be);
827 dump_ref_action(fs_info, ra);
828 kfree(ref);
829 kfree(ra);
830 goto out_unlock;
831 }
832 exist->num_refs--;
833 if (exist->num_refs == 0) {
834 rb_erase(&exist->node, &be->refs);
835 kfree(exist);
836 }
837 } else if (!be->metadata) {
838 exist->num_refs++;
839 } else {
840 btrfs_err(fs_info,
841"attempting to add another ref for an existing ref on a tree block");
842 dump_block_entry(fs_info, be);
843 dump_ref_action(fs_info, ra);
844 kfree(ref);
845 kfree(ra);
846 goto out_unlock;
847 }
848 kfree(ref);
849 } else {
850 if (action == BTRFS_DROP_DELAYED_REF) {
851 btrfs_err(fs_info,
852"dropping a ref for a root that doesn't have a ref on the block");
853 dump_block_entry(fs_info, be);
854 dump_ref_action(fs_info, ra);
855 kfree(ref);
856 kfree(ra);
857 goto out_unlock;
858 }
859 }
860
861 if (!parent && !re) {
862 re = lookup_root_entry(&be->roots, ref_root);
863 if (!re) {
864 /*
865 * This shouldn't happen because we will add our re
866 * above when we lookup the be with !parent, but just in
867 * case catch this case so we don't panic because I
868 * didn't think of some other corner case.
869 */
870 btrfs_err(fs_info, "failed to find root %llu for %llu",
871 generic_ref->real_root, be->bytenr);
872 dump_block_entry(fs_info, be);
873 dump_ref_action(fs_info, ra);
874 kfree(ra);
875 goto out_unlock;
876 }
877 }
878 if (action == BTRFS_DROP_DELAYED_REF) {
879 if (re)
880 re->num_refs--;
881 be->num_refs--;
882 } else if (action == BTRFS_ADD_DELAYED_REF) {
883 be->num_refs++;
884 if (re)
885 re->num_refs++;
886 }
887 list_add_tail(&ra->list, &be->actions);
888 ret = 0;
889out_unlock:
890 spin_unlock(&fs_info->ref_verify_lock);
891out:
892 if (ret) {
893 btrfs_free_ref_cache(fs_info);
894 btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
895 }
896 return ret;
897}
898
899/* Free up the ref cache */
900void btrfs_free_ref_cache(struct btrfs_fs_info *fs_info)
901{
902 struct block_entry *be;
903 struct rb_node *n;
904
905 if (!btrfs_test_opt(fs_info, REF_VERIFY))
906 return;
907
908 spin_lock(&fs_info->ref_verify_lock);
909 while ((n = rb_first(&fs_info->block_tree))) {
910 be = rb_entry(n, struct block_entry, node);
911 rb_erase(&be->node, &fs_info->block_tree);
912 free_block_entry(be);
913 cond_resched_lock(&fs_info->ref_verify_lock);
914 }
915 spin_unlock(&fs_info->ref_verify_lock);
916}
917
918void btrfs_free_ref_tree_range(struct btrfs_fs_info *fs_info, u64 start,
919 u64 len)
920{
921 struct block_entry *be = NULL, *entry;
922 struct rb_node *n;
923
924 if (!btrfs_test_opt(fs_info, REF_VERIFY))
925 return;
926
927 spin_lock(&fs_info->ref_verify_lock);
928 n = fs_info->block_tree.rb_node;
929 while (n) {
930 entry = rb_entry(n, struct block_entry, node);
931 if (entry->bytenr < start) {
932 n = n->rb_right;
933 } else if (entry->bytenr > start) {
934 n = n->rb_left;
935 } else {
936 be = entry;
937 break;
938 }
939 /* We want to get as close to start as possible */
940 if (be == NULL ||
941 (entry->bytenr < start && be->bytenr > start) ||
942 (entry->bytenr < start && entry->bytenr > be->bytenr))
943 be = entry;
944 }
945
946 /*
947 * Could have an empty block group, maybe have something to check for
948 * this case to verify we were actually empty?
949 */
950 if (!be) {
951 spin_unlock(&fs_info->ref_verify_lock);
952 return;
953 }
954
955 n = &be->node;
956 while (n) {
957 be = rb_entry(n, struct block_entry, node);
958 n = rb_next(n);
959 if (be->bytenr < start && be->bytenr + be->len > start) {
960 btrfs_err(fs_info,
961 "block entry overlaps a block group [%llu,%llu]!",
962 start, len);
963 dump_block_entry(fs_info, be);
964 continue;
965 }
966 if (be->bytenr < start)
967 continue;
968 if (be->bytenr >= start + len)
969 break;
970 if (be->bytenr + be->len > start + len) {
971 btrfs_err(fs_info,
972 "block entry overlaps a block group [%llu,%llu]!",
973 start, len);
974 dump_block_entry(fs_info, be);
975 }
976 rb_erase(&be->node, &fs_info->block_tree);
977 free_block_entry(be);
978 }
979 spin_unlock(&fs_info->ref_verify_lock);
980}
981
982/* Walk down all roots and build the ref tree, meant to be called at mount */
983int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
984{
985 struct btrfs_root *extent_root;
986 struct btrfs_path *path;
987 struct extent_buffer *eb;
988 int tree_block_level = 0;
989 u64 bytenr = 0, num_bytes = 0;
990 int ret, level;
991
992 if (!btrfs_test_opt(fs_info, REF_VERIFY))
993 return 0;
994
995 path = btrfs_alloc_path();
996 if (!path)
997 return -ENOMEM;
998
999 extent_root = btrfs_extent_root(fs_info, 0);
1000 eb = btrfs_read_lock_root_node(extent_root);
1001 level = btrfs_header_level(eb);
1002 path->nodes[level] = eb;
1003 path->slots[level] = 0;
1004 path->locks[level] = BTRFS_READ_LOCK;
1005
1006 while (1) {
1007 /*
1008 * We have to keep track of the bytenr/num_bytes we last hit
1009 * because we could have run out of space for an inline ref, and
1010 * would have had to added a ref key item which may appear on a
1011 * different leaf from the original extent item.
1012 */
1013 ret = walk_down_tree(extent_root, path, level,
1014 &bytenr, &num_bytes, &tree_block_level);
1015 if (ret)
1016 break;
1017 ret = walk_up_tree(path, &level);
1018 if (ret < 0)
1019 break;
1020 if (ret > 0) {
1021 ret = 0;
1022 break;
1023 }
1024 }
1025 if (ret) {
1026 btrfs_free_ref_cache(fs_info);
1027 btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
1028 }
1029 btrfs_free_path(path);
1030 return ret;
1031}