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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 void inline __save_stack_trace(struct ref_action *ra)
222{
223}
224
225static void inline __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 }
290 kfree(be);
291 return exist;
292 }
293
294 be->num_refs = 0;
295 be->metadata = 0;
296 be->from_disk = 0;
297 be->roots = RB_ROOT;
298 be->refs = RB_ROOT;
299 INIT_LIST_HEAD(&be->actions);
300 if (root_objectid)
301 insert_root_entry(&be->roots, re);
302 else
303 kfree(re);
304 return be;
305}
306
307static int add_tree_block(struct btrfs_fs_info *fs_info, u64 ref_root,
308 u64 parent, u64 bytenr, int level)
309{
310 struct block_entry *be;
311 struct root_entry *re;
312 struct ref_entry *ref = NULL, *exist;
313
314 ref = kmalloc(sizeof(struct ref_entry), GFP_KERNEL);
315 if (!ref)
316 return -ENOMEM;
317
318 if (parent)
319 ref->root_objectid = 0;
320 else
321 ref->root_objectid = ref_root;
322 ref->parent = parent;
323 ref->owner = level;
324 ref->offset = 0;
325 ref->num_refs = 1;
326
327 be = add_block_entry(fs_info, bytenr, fs_info->nodesize, ref_root);
328 if (IS_ERR(be)) {
329 kfree(ref);
330 return PTR_ERR(be);
331 }
332 be->num_refs++;
333 be->from_disk = 1;
334 be->metadata = 1;
335
336 if (!parent) {
337 ASSERT(ref_root);
338 re = lookup_root_entry(&be->roots, ref_root);
339 ASSERT(re);
340 re->num_refs++;
341 }
342 exist = insert_ref_entry(&be->refs, ref);
343 if (exist) {
344 exist->num_refs++;
345 kfree(ref);
346 }
347 spin_unlock(&fs_info->ref_verify_lock);
348
349 return 0;
350}
351
352static int add_shared_data_ref(struct btrfs_fs_info *fs_info,
353 u64 parent, u32 num_refs, u64 bytenr,
354 u64 num_bytes)
355{
356 struct block_entry *be;
357 struct ref_entry *ref;
358
359 ref = kzalloc(sizeof(struct ref_entry), GFP_KERNEL);
360 if (!ref)
361 return -ENOMEM;
362 be = add_block_entry(fs_info, bytenr, num_bytes, 0);
363 if (IS_ERR(be)) {
364 kfree(ref);
365 return PTR_ERR(be);
366 }
367 be->num_refs += num_refs;
368
369 ref->parent = parent;
370 ref->num_refs = num_refs;
371 if (insert_ref_entry(&be->refs, ref)) {
372 spin_unlock(&fs_info->ref_verify_lock);
373 btrfs_err(fs_info, "existing shared ref when reading from disk?");
374 kfree(ref);
375 return -EINVAL;
376 }
377 spin_unlock(&fs_info->ref_verify_lock);
378 return 0;
379}
380
381static int add_extent_data_ref(struct btrfs_fs_info *fs_info,
382 struct extent_buffer *leaf,
383 struct btrfs_extent_data_ref *dref,
384 u64 bytenr, u64 num_bytes)
385{
386 struct block_entry *be;
387 struct ref_entry *ref;
388 struct root_entry *re;
389 u64 ref_root = btrfs_extent_data_ref_root(leaf, dref);
390 u64 owner = btrfs_extent_data_ref_objectid(leaf, dref);
391 u64 offset = btrfs_extent_data_ref_offset(leaf, dref);
392 u32 num_refs = btrfs_extent_data_ref_count(leaf, dref);
393
394 ref = kzalloc(sizeof(struct ref_entry), GFP_KERNEL);
395 if (!ref)
396 return -ENOMEM;
397 be = add_block_entry(fs_info, bytenr, num_bytes, ref_root);
398 if (IS_ERR(be)) {
399 kfree(ref);
400 return PTR_ERR(be);
401 }
402 be->num_refs += num_refs;
403
404 ref->parent = 0;
405 ref->owner = owner;
406 ref->root_objectid = ref_root;
407 ref->offset = offset;
408 ref->num_refs = num_refs;
409 if (insert_ref_entry(&be->refs, ref)) {
410 spin_unlock(&fs_info->ref_verify_lock);
411 btrfs_err(fs_info, "existing ref when reading from disk?");
412 kfree(ref);
413 return -EINVAL;
414 }
415
416 re = lookup_root_entry(&be->roots, ref_root);
417 if (!re) {
418 spin_unlock(&fs_info->ref_verify_lock);
419 btrfs_err(fs_info, "missing root in new block entry?");
420 return -EINVAL;
421 }
422 re->num_refs += num_refs;
423 spin_unlock(&fs_info->ref_verify_lock);
424 return 0;
425}
426
427static int process_extent_item(struct btrfs_fs_info *fs_info,
428 struct btrfs_path *path, struct btrfs_key *key,
429 int slot, int *tree_block_level)
430{
431 struct btrfs_extent_item *ei;
432 struct btrfs_extent_inline_ref *iref;
433 struct btrfs_extent_data_ref *dref;
434 struct btrfs_shared_data_ref *sref;
435 struct extent_buffer *leaf = path->nodes[0];
436 u32 item_size = btrfs_item_size_nr(leaf, slot);
437 unsigned long end, ptr;
438 u64 offset, flags, count;
439 int type, ret;
440
441 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
442 flags = btrfs_extent_flags(leaf, ei);
443
444 if ((key->type == BTRFS_EXTENT_ITEM_KEY) &&
445 flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
446 struct btrfs_tree_block_info *info;
447
448 info = (struct btrfs_tree_block_info *)(ei + 1);
449 *tree_block_level = btrfs_tree_block_level(leaf, info);
450 iref = (struct btrfs_extent_inline_ref *)(info + 1);
451 } else {
452 if (key->type == BTRFS_METADATA_ITEM_KEY)
453 *tree_block_level = key->offset;
454 iref = (struct btrfs_extent_inline_ref *)(ei + 1);
455 }
456
457 ptr = (unsigned long)iref;
458 end = (unsigned long)ei + item_size;
459 while (ptr < end) {
460 iref = (struct btrfs_extent_inline_ref *)ptr;
461 type = btrfs_extent_inline_ref_type(leaf, iref);
462 offset = btrfs_extent_inline_ref_offset(leaf, iref);
463 switch (type) {
464 case BTRFS_TREE_BLOCK_REF_KEY:
465 ret = add_tree_block(fs_info, offset, 0, key->objectid,
466 *tree_block_level);
467 break;
468 case BTRFS_SHARED_BLOCK_REF_KEY:
469 ret = add_tree_block(fs_info, 0, offset, key->objectid,
470 *tree_block_level);
471 break;
472 case BTRFS_EXTENT_DATA_REF_KEY:
473 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
474 ret = add_extent_data_ref(fs_info, leaf, dref,
475 key->objectid, key->offset);
476 break;
477 case BTRFS_SHARED_DATA_REF_KEY:
478 sref = (struct btrfs_shared_data_ref *)(iref + 1);
479 count = btrfs_shared_data_ref_count(leaf, sref);
480 ret = add_shared_data_ref(fs_info, offset, count,
481 key->objectid, key->offset);
482 break;
483 default:
484 btrfs_err(fs_info, "invalid key type in iref");
485 ret = -EINVAL;
486 break;
487 }
488 if (ret)
489 break;
490 ptr += btrfs_extent_inline_ref_size(type);
491 }
492 return ret;
493}
494
495static int process_leaf(struct btrfs_root *root,
496 struct btrfs_path *path, u64 *bytenr, u64 *num_bytes)
497{
498 struct btrfs_fs_info *fs_info = root->fs_info;
499 struct extent_buffer *leaf = path->nodes[0];
500 struct btrfs_extent_data_ref *dref;
501 struct btrfs_shared_data_ref *sref;
502 u32 count;
503 int i = 0, tree_block_level = 0, ret = 0;
504 struct btrfs_key key;
505 int nritems = btrfs_header_nritems(leaf);
506
507 for (i = 0; i < nritems; i++) {
508 btrfs_item_key_to_cpu(leaf, &key, i);
509 switch (key.type) {
510 case BTRFS_EXTENT_ITEM_KEY:
511 *num_bytes = key.offset;
512 /* fall through */
513 case BTRFS_METADATA_ITEM_KEY:
514 *bytenr = key.objectid;
515 ret = process_extent_item(fs_info, path, &key, i,
516 &tree_block_level);
517 break;
518 case BTRFS_TREE_BLOCK_REF_KEY:
519 ret = add_tree_block(fs_info, key.offset, 0,
520 key.objectid, tree_block_level);
521 break;
522 case BTRFS_SHARED_BLOCK_REF_KEY:
523 ret = add_tree_block(fs_info, 0, key.offset,
524 key.objectid, tree_block_level);
525 break;
526 case BTRFS_EXTENT_DATA_REF_KEY:
527 dref = btrfs_item_ptr(leaf, i,
528 struct btrfs_extent_data_ref);
529 ret = add_extent_data_ref(fs_info, leaf, dref, *bytenr,
530 *num_bytes);
531 break;
532 case BTRFS_SHARED_DATA_REF_KEY:
533 sref = btrfs_item_ptr(leaf, i,
534 struct btrfs_shared_data_ref);
535 count = btrfs_shared_data_ref_count(leaf, sref);
536 ret = add_shared_data_ref(fs_info, key.offset, count,
537 *bytenr, *num_bytes);
538 break;
539 default:
540 break;
541 }
542 if (ret)
543 break;
544 }
545 return ret;
546}
547
548/* Walk down to the leaf from the given level */
549static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
550 int level, u64 *bytenr, u64 *num_bytes)
551{
552 struct btrfs_fs_info *fs_info = root->fs_info;
553 struct extent_buffer *eb;
554 u64 block_bytenr, gen;
555 int ret = 0;
556
557 while (level >= 0) {
558 if (level) {
559 struct btrfs_key first_key;
560
561 block_bytenr = btrfs_node_blockptr(path->nodes[level],
562 path->slots[level]);
563 gen = btrfs_node_ptr_generation(path->nodes[level],
564 path->slots[level]);
565 btrfs_node_key_to_cpu(path->nodes[level], &first_key,
566 path->slots[level]);
567 eb = read_tree_block(fs_info, block_bytenr, gen,
568 level - 1, &first_key);
569 if (IS_ERR(eb))
570 return PTR_ERR(eb);
571 if (!extent_buffer_uptodate(eb)) {
572 free_extent_buffer(eb);
573 return -EIO;
574 }
575 btrfs_tree_read_lock(eb);
576 btrfs_set_lock_blocking_read(eb);
577 path->nodes[level-1] = eb;
578 path->slots[level-1] = 0;
579 path->locks[level-1] = BTRFS_READ_LOCK_BLOCKING;
580 } else {
581 ret = process_leaf(root, path, bytenr, num_bytes);
582 if (ret)
583 break;
584 }
585 level--;
586 }
587 return ret;
588}
589
590/* Walk up to the next node that needs to be processed */
591static int walk_up_tree(struct btrfs_path *path, int *level)
592{
593 int l;
594
595 for (l = 0; l < BTRFS_MAX_LEVEL; l++) {
596 if (!path->nodes[l])
597 continue;
598 if (l) {
599 path->slots[l]++;
600 if (path->slots[l] <
601 btrfs_header_nritems(path->nodes[l])) {
602 *level = l;
603 return 0;
604 }
605 }
606 btrfs_tree_unlock_rw(path->nodes[l], path->locks[l]);
607 free_extent_buffer(path->nodes[l]);
608 path->nodes[l] = NULL;
609 path->slots[l] = 0;
610 path->locks[l] = 0;
611 }
612
613 return 1;
614}
615
616static void dump_ref_action(struct btrfs_fs_info *fs_info,
617 struct ref_action *ra)
618{
619 btrfs_err(fs_info,
620" Ref action %d, root %llu, ref_root %llu, parent %llu, owner %llu, offset %llu, num_refs %llu",
621 ra->action, ra->root, ra->ref.root_objectid, ra->ref.parent,
622 ra->ref.owner, ra->ref.offset, ra->ref.num_refs);
623 __print_stack_trace(fs_info, ra);
624}
625
626/*
627 * Dumps all the information from the block entry to printk, it's going to be
628 * awesome.
629 */
630static void dump_block_entry(struct btrfs_fs_info *fs_info,
631 struct block_entry *be)
632{
633 struct ref_entry *ref;
634 struct root_entry *re;
635 struct ref_action *ra;
636 struct rb_node *n;
637
638 btrfs_err(fs_info,
639"dumping block entry [%llu %llu], num_refs %llu, metadata %d, from disk %d",
640 be->bytenr, be->len, be->num_refs, be->metadata,
641 be->from_disk);
642
643 for (n = rb_first(&be->refs); n; n = rb_next(n)) {
644 ref = rb_entry(n, struct ref_entry, node);
645 btrfs_err(fs_info,
646" ref root %llu, parent %llu, owner %llu, offset %llu, num_refs %llu",
647 ref->root_objectid, ref->parent, ref->owner,
648 ref->offset, ref->num_refs);
649 }
650
651 for (n = rb_first(&be->roots); n; n = rb_next(n)) {
652 re = rb_entry(n, struct root_entry, node);
653 btrfs_err(fs_info, " root entry %llu, num_refs %llu",
654 re->root_objectid, re->num_refs);
655 }
656
657 list_for_each_entry(ra, &be->actions, list)
658 dump_ref_action(fs_info, ra);
659}
660
661/*
662 * btrfs_ref_tree_mod: called when we modify a ref for a bytenr
663 *
664 * This will add an action item to the given bytenr and do sanity checks to make
665 * sure we haven't messed something up. If we are making a new allocation and
666 * this block entry has history we will delete all previous actions as long as
667 * our sanity checks pass as they are no longer needed.
668 */
669int btrfs_ref_tree_mod(struct btrfs_fs_info *fs_info,
670 struct btrfs_ref *generic_ref)
671{
672 struct ref_entry *ref = NULL, *exist;
673 struct ref_action *ra = NULL;
674 struct block_entry *be = NULL;
675 struct root_entry *re = NULL;
676 int action = generic_ref->action;
677 int ret = 0;
678 bool metadata;
679 u64 bytenr = generic_ref->bytenr;
680 u64 num_bytes = generic_ref->len;
681 u64 parent = generic_ref->parent;
682 u64 ref_root;
683 u64 owner;
684 u64 offset;
685
686 if (!btrfs_test_opt(fs_info, REF_VERIFY))
687 return 0;
688
689 if (generic_ref->type == BTRFS_REF_METADATA) {
690 ref_root = generic_ref->tree_ref.root;
691 owner = generic_ref->tree_ref.level;
692 offset = 0;
693 } else {
694 ref_root = generic_ref->data_ref.ref_root;
695 owner = generic_ref->data_ref.ino;
696 offset = generic_ref->data_ref.offset;
697 }
698 metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
699
700 ref = kzalloc(sizeof(struct ref_entry), GFP_NOFS);
701 ra = kmalloc(sizeof(struct ref_action), GFP_NOFS);
702 if (!ra || !ref) {
703 kfree(ref);
704 kfree(ra);
705 ret = -ENOMEM;
706 goto out;
707 }
708
709 if (parent) {
710 ref->parent = parent;
711 } else {
712 ref->root_objectid = ref_root;
713 ref->owner = owner;
714 ref->offset = offset;
715 }
716 ref->num_refs = (action == BTRFS_DROP_DELAYED_REF) ? -1 : 1;
717
718 memcpy(&ra->ref, ref, sizeof(struct ref_entry));
719 /*
720 * Save the extra info from the delayed ref in the ref action to make it
721 * easier to figure out what is happening. The real ref's we add to the
722 * ref tree need to reflect what we save on disk so it matches any
723 * on-disk refs we pre-loaded.
724 */
725 ra->ref.owner = owner;
726 ra->ref.offset = offset;
727 ra->ref.root_objectid = ref_root;
728 __save_stack_trace(ra);
729
730 INIT_LIST_HEAD(&ra->list);
731 ra->action = action;
732 ra->root = generic_ref->real_root;
733
734 /*
735 * This is an allocation, preallocate the block_entry in case we haven't
736 * used it before.
737 */
738 ret = -EINVAL;
739 if (action == BTRFS_ADD_DELAYED_EXTENT) {
740 /*
741 * For subvol_create we'll just pass in whatever the parent root
742 * is and the new root objectid, so let's not treat the passed
743 * in root as if it really has a ref for this bytenr.
744 */
745 be = add_block_entry(fs_info, bytenr, num_bytes, ref_root);
746 if (IS_ERR(be)) {
747 kfree(ra);
748 ret = PTR_ERR(be);
749 goto out;
750 }
751 be->num_refs++;
752 if (metadata)
753 be->metadata = 1;
754
755 if (be->num_refs != 1) {
756 btrfs_err(fs_info,
757 "re-allocated a block that still has references to it!");
758 dump_block_entry(fs_info, be);
759 dump_ref_action(fs_info, ra);
760 goto out_unlock;
761 }
762
763 while (!list_empty(&be->actions)) {
764 struct ref_action *tmp;
765
766 tmp = list_first_entry(&be->actions, struct ref_action,
767 list);
768 list_del(&tmp->list);
769 kfree(tmp);
770 }
771 } else {
772 struct root_entry *tmp;
773
774 if (!parent) {
775 re = kmalloc(sizeof(struct root_entry), GFP_NOFS);
776 if (!re) {
777 kfree(ref);
778 kfree(ra);
779 ret = -ENOMEM;
780 goto out;
781 }
782 /*
783 * This is the root that is modifying us, so it's the
784 * one we want to lookup below when we modify the
785 * re->num_refs.
786 */
787 ref_root = generic_ref->real_root;
788 re->root_objectid = generic_ref->real_root;
789 re->num_refs = 0;
790 }
791
792 spin_lock(&fs_info->ref_verify_lock);
793 be = lookup_block_entry(&fs_info->block_tree, bytenr);
794 if (!be) {
795 btrfs_err(fs_info,
796"trying to do action %d to bytenr %llu num_bytes %llu but there is no existing entry!",
797 action, (unsigned long long)bytenr,
798 (unsigned long long)num_bytes);
799 dump_ref_action(fs_info, ra);
800 kfree(ref);
801 kfree(ra);
802 goto out_unlock;
803 }
804
805 if (!parent) {
806 tmp = insert_root_entry(&be->roots, re);
807 if (tmp) {
808 kfree(re);
809 re = tmp;
810 }
811 }
812 }
813
814 exist = insert_ref_entry(&be->refs, ref);
815 if (exist) {
816 if (action == BTRFS_DROP_DELAYED_REF) {
817 if (exist->num_refs == 0) {
818 btrfs_err(fs_info,
819"dropping a ref for a existing root that doesn't have a ref on the block");
820 dump_block_entry(fs_info, be);
821 dump_ref_action(fs_info, ra);
822 kfree(ra);
823 goto out_unlock;
824 }
825 exist->num_refs--;
826 if (exist->num_refs == 0) {
827 rb_erase(&exist->node, &be->refs);
828 kfree(exist);
829 }
830 } else if (!be->metadata) {
831 exist->num_refs++;
832 } else {
833 btrfs_err(fs_info,
834"attempting to add another ref for an existing ref on a tree block");
835 dump_block_entry(fs_info, be);
836 dump_ref_action(fs_info, ra);
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(ra);
848 goto out_unlock;
849 }
850 }
851
852 if (!parent && !re) {
853 re = lookup_root_entry(&be->roots, ref_root);
854 if (!re) {
855 /*
856 * This shouldn't happen because we will add our re
857 * above when we lookup the be with !parent, but just in
858 * case catch this case so we don't panic because I
859 * didn't think of some other corner case.
860 */
861 btrfs_err(fs_info, "failed to find root %llu for %llu",
862 generic_ref->real_root, be->bytenr);
863 dump_block_entry(fs_info, be);
864 dump_ref_action(fs_info, ra);
865 kfree(ra);
866 goto out_unlock;
867 }
868 }
869 if (action == BTRFS_DROP_DELAYED_REF) {
870 if (re)
871 re->num_refs--;
872 be->num_refs--;
873 } else if (action == BTRFS_ADD_DELAYED_REF) {
874 be->num_refs++;
875 if (re)
876 re->num_refs++;
877 }
878 list_add_tail(&ra->list, &be->actions);
879 ret = 0;
880out_unlock:
881 spin_unlock(&fs_info->ref_verify_lock);
882out:
883 if (ret)
884 btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
885 return ret;
886}
887
888/* Free up the ref cache */
889void btrfs_free_ref_cache(struct btrfs_fs_info *fs_info)
890{
891 struct block_entry *be;
892 struct rb_node *n;
893
894 if (!btrfs_test_opt(fs_info, REF_VERIFY))
895 return;
896
897 spin_lock(&fs_info->ref_verify_lock);
898 while ((n = rb_first(&fs_info->block_tree))) {
899 be = rb_entry(n, struct block_entry, node);
900 rb_erase(&be->node, &fs_info->block_tree);
901 free_block_entry(be);
902 cond_resched_lock(&fs_info->ref_verify_lock);
903 }
904 spin_unlock(&fs_info->ref_verify_lock);
905}
906
907void btrfs_free_ref_tree_range(struct btrfs_fs_info *fs_info, u64 start,
908 u64 len)
909{
910 struct block_entry *be = NULL, *entry;
911 struct rb_node *n;
912
913 if (!btrfs_test_opt(fs_info, REF_VERIFY))
914 return;
915
916 spin_lock(&fs_info->ref_verify_lock);
917 n = fs_info->block_tree.rb_node;
918 while (n) {
919 entry = rb_entry(n, struct block_entry, node);
920 if (entry->bytenr < start) {
921 n = n->rb_right;
922 } else if (entry->bytenr > start) {
923 n = n->rb_left;
924 } else {
925 be = entry;
926 break;
927 }
928 /* We want to get as close to start as possible */
929 if (be == NULL ||
930 (entry->bytenr < start && be->bytenr > start) ||
931 (entry->bytenr < start && entry->bytenr > be->bytenr))
932 be = entry;
933 }
934
935 /*
936 * Could have an empty block group, maybe have something to check for
937 * this case to verify we were actually empty?
938 */
939 if (!be) {
940 spin_unlock(&fs_info->ref_verify_lock);
941 return;
942 }
943
944 n = &be->node;
945 while (n) {
946 be = rb_entry(n, struct block_entry, node);
947 n = rb_next(n);
948 if (be->bytenr < start && be->bytenr + be->len > start) {
949 btrfs_err(fs_info,
950 "block entry overlaps a block group [%llu,%llu]!",
951 start, len);
952 dump_block_entry(fs_info, be);
953 continue;
954 }
955 if (be->bytenr < start)
956 continue;
957 if (be->bytenr >= start + len)
958 break;
959 if (be->bytenr + be->len > start + len) {
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 }
965 rb_erase(&be->node, &fs_info->block_tree);
966 free_block_entry(be);
967 }
968 spin_unlock(&fs_info->ref_verify_lock);
969}
970
971/* Walk down all roots and build the ref tree, meant to be called at mount */
972int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
973{
974 struct btrfs_path *path;
975 struct extent_buffer *eb;
976 u64 bytenr = 0, num_bytes = 0;
977 int ret, level;
978
979 if (!btrfs_test_opt(fs_info, REF_VERIFY))
980 return 0;
981
982 path = btrfs_alloc_path();
983 if (!path)
984 return -ENOMEM;
985
986 eb = btrfs_read_lock_root_node(fs_info->extent_root);
987 btrfs_set_lock_blocking_read(eb);
988 level = btrfs_header_level(eb);
989 path->nodes[level] = eb;
990 path->slots[level] = 0;
991 path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
992
993 while (1) {
994 /*
995 * We have to keep track of the bytenr/num_bytes we last hit
996 * because we could have run out of space for an inline ref, and
997 * would have had to added a ref key item which may appear on a
998 * different leaf from the original extent item.
999 */
1000 ret = walk_down_tree(fs_info->extent_root, path, level,
1001 &bytenr, &num_bytes);
1002 if (ret)
1003 break;
1004 ret = walk_up_tree(path, &level);
1005 if (ret < 0)
1006 break;
1007 if (ret > 0) {
1008 ret = 0;
1009 break;
1010 }
1011 }
1012 if (ret) {
1013 btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
1014 btrfs_free_ref_cache(fs_info);
1015 }
1016 btrfs_free_path(path);
1017 return ret;
1018}