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

source code of linux/fs/btrfs/ref-verify.c