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-rw-r--r--fs/btrfs/ref-verify.c1031
1 files changed, 1031 insertions, 0 deletions
diff --git a/fs/btrfs/ref-verify.c b/fs/btrfs/ref-verify.c
new file mode 100644
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+++ b/fs/btrfs/ref-verify.c
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1/*
2 * Copyright (C) 2014 Facebook. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/sched.h>
20#include <linux/stacktrace.h>
21#include "ctree.h"
22#include "disk-io.h"
23#include "locking.h"
24#include "delayed-ref.h"
25#include "ref-verify.h"
26
27/*
28 * Used to keep track the roots and number of refs each root has for a given
29 * bytenr. This just tracks the number of direct references, no shared
30 * references.
31 */
32struct root_entry {
33 u64 root_objectid;
34 u64 num_refs;
35 struct rb_node node;
36};
37
38/*
39 * These are meant to represent what should exist in the extent tree, these can
40 * be used to verify the extent tree is consistent as these should all match
41 * what the extent tree says.
42 */
43struct ref_entry {
44 u64 root_objectid;
45 u64 parent;
46 u64 owner;
47 u64 offset;
48 u64 num_refs;
49 struct rb_node node;
50};
51
52#define MAX_TRACE 16
53
54/*
55 * Whenever we add/remove a reference we record the action. The action maps
56 * back to the delayed ref action. We hold the ref we are changing in the
57 * action so we can account for the history properly, and we record the root we
58 * were called with since it could be different from ref_root. We also store
59 * stack traces because thats how I roll.
60 */
61struct ref_action {
62 int action;
63 u64 root;
64 struct ref_entry ref;
65 struct list_head list;
66 unsigned long trace[MAX_TRACE];
67 unsigned int trace_len;
68};
69
70/*
71 * One of these for every block we reference, it holds the roots and references
72 * to it as well as all of the ref actions that have occured to it. We never
73 * free it until we unmount the file system in order to make sure re-allocations
74 * are happening properly.
75 */
76struct block_entry {
77 u64 bytenr;
78 u64 len;
79 u64 num_refs;
80 int metadata;
81 int from_disk;
82 struct rb_root roots;
83 struct rb_root refs;
84 struct rb_node node;
85 struct list_head actions;
86};
87
88static struct block_entry *insert_block_entry(struct rb_root *root,
89 struct block_entry *be)
90{
91 struct rb_node **p = &root->rb_node;
92 struct rb_node *parent_node = NULL;
93 struct block_entry *entry;
94
95 while (*p) {
96 parent_node = *p;
97 entry = rb_entry(parent_node, struct block_entry, node);
98 if (entry->bytenr > be->bytenr)
99 p = &(*p)->rb_left;
100 else if (entry->bytenr < be->bytenr)
101 p = &(*p)->rb_right;
102 else
103 return entry;
104 }
105
106 rb_link_node(&be->node, parent_node, p);
107 rb_insert_color(&be->node, root);
108 return NULL;
109}
110
111static struct block_entry *lookup_block_entry(struct rb_root *root, u64 bytenr)
112{
113 struct rb_node *n;
114 struct block_entry *entry = NULL;
115
116 n = root->rb_node;
117 while (n) {
118 entry = rb_entry(n, struct block_entry, node);
119 if (entry->bytenr < bytenr)
120 n = n->rb_right;
121 else if (entry->bytenr > bytenr)
122 n = n->rb_left;
123 else
124 return entry;
125 }
126 return NULL;
127}
128
129static struct root_entry *insert_root_entry(struct rb_root *root,
130 struct root_entry *re)
131{
132 struct rb_node **p = &root->rb_node;
133 struct rb_node *parent_node = NULL;
134 struct root_entry *entry;
135
136 while (*p) {
137 parent_node = *p;
138 entry = rb_entry(parent_node, struct root_entry, node);
139 if (entry->root_objectid > re->root_objectid)
140 p = &(*p)->rb_left;
141 else if (entry->root_objectid < re->root_objectid)
142 p = &(*p)->rb_right;
143 else
144 return entry;
145 }
146
147 rb_link_node(&re->node, parent_node, p);
148 rb_insert_color(&re->node, root);
149 return NULL;
150
151}
152
153static int comp_refs(struct ref_entry *ref1, struct ref_entry *ref2)
154{
155 if (ref1->root_objectid < ref2->root_objectid)
156 return -1;
157 if (ref1->root_objectid > ref2->root_objectid)
158 return 1;
159 if (ref1->parent < ref2->parent)
160 return -1;
161 if (ref1->parent > ref2->parent)
162 return 1;
163 if (ref1->owner < ref2->owner)
164 return -1;
165 if (ref1->owner > ref2->owner)
166 return 1;
167 if (ref1->offset < ref2->offset)
168 return -1;
169 if (ref1->offset > ref2->offset)
170 return 1;
171 return 0;
172}
173
174static struct ref_entry *insert_ref_entry(struct rb_root *root,
175 struct ref_entry *ref)
176{
177 struct rb_node **p = &root->rb_node;
178 struct rb_node *parent_node = NULL;
179 struct ref_entry *entry;
180 int cmp;
181
182 while (*p) {
183 parent_node = *p;
184 entry = rb_entry(parent_node, struct ref_entry, node);
185 cmp = comp_refs(entry, ref);
186 if (cmp > 0)
187 p = &(*p)->rb_left;
188 else if (cmp < 0)
189 p = &(*p)->rb_right;
190 else
191 return entry;
192 }
193
194 rb_link_node(&ref->node, parent_node, p);
195 rb_insert_color(&ref->node, root);
196 return NULL;
197
198}
199
200static struct root_entry *lookup_root_entry(struct rb_root *root, u64 objectid)
201{
202 struct rb_node *n;
203 struct root_entry *entry = NULL;
204
205 n = root->rb_node;
206 while (n) {
207 entry = rb_entry(n, struct root_entry, node);
208 if (entry->root_objectid < objectid)
209 n = n->rb_right;
210 else if (entry->root_objectid > objectid)
211 n = n->rb_left;
212 else
213 return entry;
214 }
215 return NULL;
216}
217
218#ifdef CONFIG_STACKTRACE
219static void __save_stack_trace(struct ref_action *ra)
220{
221 struct stack_trace stack_trace;
222
223 stack_trace.max_entries = MAX_TRACE;
224 stack_trace.nr_entries = 0;
225 stack_trace.entries = ra->trace;
226 stack_trace.skip = 2;
227 save_stack_trace(&stack_trace);
228 ra->trace_len = stack_trace.nr_entries;
229}
230
231static void __print_stack_trace(struct btrfs_fs_info *fs_info,
232 struct ref_action *ra)
233{
234 struct stack_trace trace;
235
236 if (ra->trace_len == 0) {
237 btrfs_err(fs_info, " ref-verify: no stacktrace");
238 return;
239 }
240 trace.nr_entries = ra->trace_len;
241 trace.entries = ra->trace;
242 print_stack_trace(&trace, 2);
243}
244#else
245static void inline __save_stack_trace(struct ref_action *ra)
246{
247}
248
249static void inline __print_stack_trace(struct btrfs_fs_info *fs_info,
250 struct ref_action *ra)
251{
252 btrfs_err(fs_info, " ref-verify: no stacktrace support");
253}
254#endif
255
256static void free_block_entry(struct block_entry *be)
257{
258 struct root_entry *re;
259 struct ref_entry *ref;
260 struct ref_action *ra;
261 struct rb_node *n;
262
263 while ((n = rb_first(&be->roots))) {
264 re = rb_entry(n, struct root_entry, node);
265 rb_erase(&re->node, &be->roots);
266 kfree(re);
267 }
268
269 while((n = rb_first(&be->refs))) {
270 ref = rb_entry(n, struct ref_entry, node);
271 rb_erase(&ref->node, &be->refs);
272 kfree(ref);
273 }
274
275 while (!list_empty(&be->actions)) {
276 ra = list_first_entry(&be->actions, struct ref_action,
277 list);
278 list_del(&ra->list);
279 kfree(ra);
280 }
281 kfree(be);
282}
283
284static struct block_entry *add_block_entry(struct btrfs_fs_info *fs_info,
285 u64 bytenr, u64 len,
286 u64 root_objectid)
287{
288 struct block_entry *be = NULL, *exist;
289 struct root_entry *re = NULL;
290
291 re = kzalloc(sizeof(struct root_entry), GFP_KERNEL);
292 be = kzalloc(sizeof(struct block_entry), GFP_KERNEL);
293 if (!be || !re) {
294 kfree(re);
295 kfree(be);
296 return ERR_PTR(-ENOMEM);
297 }
298 be->bytenr = bytenr;
299 be->len = len;
300
301 re->root_objectid = root_objectid;
302 re->num_refs = 0;
303
304 spin_lock(&fs_info->ref_verify_lock);
305 exist = insert_block_entry(&fs_info->block_tree, be);
306 if (exist) {
307 if (root_objectid) {
308 struct root_entry *exist_re;
309
310 exist_re = insert_root_entry(&exist->roots, re);
311 if (exist_re)
312 kfree(re);
313 }
314 kfree(be);
315 return exist;
316 }
317
318 be->num_refs = 0;
319 be->metadata = 0;
320 be->from_disk = 0;
321 be->roots = RB_ROOT;
322 be->refs = RB_ROOT;
323 INIT_LIST_HEAD(&be->actions);
324 if (root_objectid)
325 insert_root_entry(&be->roots, re);
326 else
327 kfree(re);
328 return be;
329}
330
331static int add_tree_block(struct btrfs_fs_info *fs_info, u64 ref_root,
332 u64 parent, u64 bytenr, int level)
333{
334 struct block_entry *be;
335 struct root_entry *re;
336 struct ref_entry *ref = NULL, *exist;
337
338 ref = kmalloc(sizeof(struct ref_entry), GFP_KERNEL);
339 if (!ref)
340 return -ENOMEM;
341
342 if (parent)
343 ref->root_objectid = 0;
344 else
345 ref->root_objectid = ref_root;
346 ref->parent = parent;
347 ref->owner = level;
348 ref->offset = 0;
349 ref->num_refs = 1;
350
351 be = add_block_entry(fs_info, bytenr, fs_info->nodesize, ref_root);
352 if (IS_ERR(be)) {
353 kfree(ref);
354 return PTR_ERR(be);
355 }
356 be->num_refs++;
357 be->from_disk = 1;
358 be->metadata = 1;
359
360 if (!parent) {
361 ASSERT(ref_root);
362 re = lookup_root_entry(&be->roots, ref_root);
363 ASSERT(re);
364 re->num_refs++;
365 }
366 exist = insert_ref_entry(&be->refs, ref);
367 if (exist) {
368 exist->num_refs++;
369 kfree(ref);
370 }
371 spin_unlock(&fs_info->ref_verify_lock);
372
373 return 0;
374}
375
376static int add_shared_data_ref(struct btrfs_fs_info *fs_info,
377 u64 parent, u32 num_refs, u64 bytenr,
378 u64 num_bytes)
379{
380 struct block_entry *be;
381 struct ref_entry *ref;
382
383 ref = kzalloc(sizeof(struct ref_entry), GFP_KERNEL);
384 if (!ref)
385 return -ENOMEM;
386 be = add_block_entry(fs_info, bytenr, num_bytes, 0);
387 if (IS_ERR(be)) {
388 kfree(ref);
389 return PTR_ERR(be);
390 }
391 be->num_refs += num_refs;
392
393 ref->parent = parent;
394 ref->num_refs = num_refs;
395 if (insert_ref_entry(&be->refs, ref)) {
396 spin_unlock(&fs_info->ref_verify_lock);
397 btrfs_err(fs_info, "existing shared ref when reading from disk?");
398 kfree(ref);
399 return -EINVAL;
400 }
401 spin_unlock(&fs_info->ref_verify_lock);
402 return 0;
403}
404
405static int add_extent_data_ref(struct btrfs_fs_info *fs_info,
406 struct extent_buffer *leaf,
407 struct btrfs_extent_data_ref *dref,
408 u64 bytenr, u64 num_bytes)
409{
410 struct block_entry *be;
411 struct ref_entry *ref;
412 struct root_entry *re;
413 u64 ref_root = btrfs_extent_data_ref_root(leaf, dref);
414 u64 owner = btrfs_extent_data_ref_objectid(leaf, dref);
415 u64 offset = btrfs_extent_data_ref_offset(leaf, dref);
416 u32 num_refs = btrfs_extent_data_ref_count(leaf, dref);
417
418 ref = kzalloc(sizeof(struct ref_entry), GFP_KERNEL);
419 if (!ref)
420 return -ENOMEM;
421 be = add_block_entry(fs_info, bytenr, num_bytes, ref_root);
422 if (IS_ERR(be)) {
423 kfree(ref);
424 return PTR_ERR(be);
425 }
426 be->num_refs += num_refs;
427
428 ref->parent = 0;
429 ref->owner = owner;
430 ref->root_objectid = ref_root;
431 ref->offset = offset;
432 ref->num_refs = num_refs;
433 if (insert_ref_entry(&be->refs, ref)) {
434 spin_unlock(&fs_info->ref_verify_lock);
435 btrfs_err(fs_info, "existing ref when reading from disk?");
436 kfree(ref);
437 return -EINVAL;
438 }
439
440 re = lookup_root_entry(&be->roots, ref_root);
441 if (!re) {
442 spin_unlock(&fs_info->ref_verify_lock);
443 btrfs_err(fs_info, "missing root in new block entry?");
444 return -EINVAL;
445 }
446 re->num_refs += num_refs;
447 spin_unlock(&fs_info->ref_verify_lock);
448 return 0;
449}
450
451static int process_extent_item(struct btrfs_fs_info *fs_info,
452 struct btrfs_path *path, struct btrfs_key *key,
453 int slot, int *tree_block_level)
454{
455 struct btrfs_extent_item *ei;
456 struct btrfs_extent_inline_ref *iref;
457 struct btrfs_extent_data_ref *dref;
458 struct btrfs_shared_data_ref *sref;
459 struct extent_buffer *leaf = path->nodes[0];
460 u32 item_size = btrfs_item_size_nr(leaf, slot);
461 unsigned long end, ptr;
462 u64 offset, flags, count;
463 int type, ret;
464
465 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
466 flags = btrfs_extent_flags(leaf, ei);
467
468 if ((key->type == BTRFS_EXTENT_ITEM_KEY) &&
469 flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
470 struct btrfs_tree_block_info *info;
471
472 info = (struct btrfs_tree_block_info *)(ei + 1);
473 *tree_block_level = btrfs_tree_block_level(leaf, info);
474 iref = (struct btrfs_extent_inline_ref *)(info + 1);
475 } else {
476 if (key->type == BTRFS_METADATA_ITEM_KEY)
477 *tree_block_level = key->offset;
478 iref = (struct btrfs_extent_inline_ref *)(ei + 1);
479 }
480
481 ptr = (unsigned long)iref;
482 end = (unsigned long)ei + item_size;
483 while (ptr < end) {
484 iref = (struct btrfs_extent_inline_ref *)ptr;
485 type = btrfs_extent_inline_ref_type(leaf, iref);
486 offset = btrfs_extent_inline_ref_offset(leaf, iref);
487 switch (type) {
488 case BTRFS_TREE_BLOCK_REF_KEY:
489 ret = add_tree_block(fs_info, offset, 0, key->objectid,
490 *tree_block_level);
491 break;
492 case BTRFS_SHARED_BLOCK_REF_KEY:
493 ret = add_tree_block(fs_info, 0, offset, key->objectid,
494 *tree_block_level);
495 break;
496 case BTRFS_EXTENT_DATA_REF_KEY:
497 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
498 ret = add_extent_data_ref(fs_info, leaf, dref,
499 key->objectid, key->offset);
500 break;
501 case BTRFS_SHARED_DATA_REF_KEY:
502 sref = (struct btrfs_shared_data_ref *)(iref + 1);
503 count = btrfs_shared_data_ref_count(leaf, sref);
504 ret = add_shared_data_ref(fs_info, offset, count,
505 key->objectid, key->offset);
506 break;
507 default:
508 btrfs_err(fs_info, "invalid key type in iref");
509 ret = -EINVAL;
510 break;
511 }
512 if (ret)
513 break;
514 ptr += btrfs_extent_inline_ref_size(type);
515 }
516 return ret;
517}
518
519static int process_leaf(struct btrfs_root *root,
520 struct btrfs_path *path, u64 *bytenr, u64 *num_bytes)
521{
522 struct btrfs_fs_info *fs_info = root->fs_info;
523 struct extent_buffer *leaf = path->nodes[0];
524 struct btrfs_extent_data_ref *dref;
525 struct btrfs_shared_data_ref *sref;
526 u32 count;
527 int i = 0, tree_block_level = 0, ret;
528 struct btrfs_key key;
529 int nritems = btrfs_header_nritems(leaf);
530
531 for (i = 0; i < nritems; i++) {
532 btrfs_item_key_to_cpu(leaf, &key, i);
533 switch (key.type) {
534 case BTRFS_EXTENT_ITEM_KEY:
535 *num_bytes = key.offset;
536 case BTRFS_METADATA_ITEM_KEY:
537 *bytenr = key.objectid;
538 ret = process_extent_item(fs_info, path, &key, i,
539 &tree_block_level);
540 break;
541 case BTRFS_TREE_BLOCK_REF_KEY:
542 ret = add_tree_block(fs_info, key.offset, 0,
543 key.objectid, tree_block_level);
544 break;
545 case BTRFS_SHARED_BLOCK_REF_KEY:
546 ret = add_tree_block(fs_info, 0, key.offset,
547 key.objectid, tree_block_level);
548 break;
549 case BTRFS_EXTENT_DATA_REF_KEY:
550 dref = btrfs_item_ptr(leaf, i,
551 struct btrfs_extent_data_ref);
552 ret = add_extent_data_ref(fs_info, leaf, dref, *bytenr,
553 *num_bytes);
554 break;
555 case BTRFS_SHARED_DATA_REF_KEY:
556 sref = btrfs_item_ptr(leaf, i,
557 struct btrfs_shared_data_ref);
558 count = btrfs_shared_data_ref_count(leaf, sref);
559 ret = add_shared_data_ref(fs_info, key.offset, count,
560 *bytenr, *num_bytes);
561 break;
562 default:
563 break;
564 }
565 if (ret)
566 break;
567 }
568 return ret;
569}
570
571/* Walk down to the leaf from the given level */
572static int walk_down_tree(struct btrfs_root *root, struct btrfs_path *path,
573 int level, u64 *bytenr, u64 *num_bytes)
574{
575 struct btrfs_fs_info *fs_info = root->fs_info;
576 struct extent_buffer *eb;
577 u64 block_bytenr, gen;
578 int ret = 0;
579
580 while (level >= 0) {
581 if (level) {
582 block_bytenr = btrfs_node_blockptr(path->nodes[level],
583 path->slots[level]);
584 gen = btrfs_node_ptr_generation(path->nodes[level],
585 path->slots[level]);
586 eb = read_tree_block(fs_info, block_bytenr, gen);
587 if (IS_ERR(eb))
588 return PTR_ERR(eb);
589 if (!extent_buffer_uptodate(eb)) {
590 free_extent_buffer(eb);
591 return -EIO;
592 }
593 btrfs_tree_read_lock(eb);
594 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
595 path->nodes[level-1] = eb;
596 path->slots[level-1] = 0;
597 path->locks[level-1] = BTRFS_READ_LOCK_BLOCKING;
598 } else {
599 ret = process_leaf(root, path, bytenr, num_bytes);
600 if (ret)
601 break;
602 }
603 level--;
604 }
605 return ret;
606}
607
608/* Walk up to the next node that needs to be processed */
609static int walk_up_tree(struct btrfs_root *root, struct btrfs_path *path,
610 int *level)
611{
612 int l;
613
614 for (l = 0; l < BTRFS_MAX_LEVEL; l++) {
615 if (!path->nodes[l])
616 continue;
617 if (l) {
618 path->slots[l]++;
619 if (path->slots[l] <
620 btrfs_header_nritems(path->nodes[l])) {
621 *level = l;
622 return 0;
623 }
624 }
625 btrfs_tree_unlock_rw(path->nodes[l], path->locks[l]);
626 free_extent_buffer(path->nodes[l]);
627 path->nodes[l] = NULL;
628 path->slots[l] = 0;
629 path->locks[l] = 0;
630 }
631
632 return 1;
633}
634
635static void dump_ref_action(struct btrfs_fs_info *fs_info,
636 struct ref_action *ra)
637{
638 btrfs_err(fs_info,
639" Ref action %d, root %llu, ref_root %llu, parent %llu, owner %llu, offset %llu, num_refs %llu",
640 ra->action, ra->root, ra->ref.root_objectid, ra->ref.parent,
641 ra->ref.owner, ra->ref.offset, ra->ref.num_refs);
642 __print_stack_trace(fs_info, ra);
643}
644
645/*
646 * Dumps all the information from the block entry to printk, it's going to be
647 * awesome.
648 */
649static void dump_block_entry(struct btrfs_fs_info *fs_info,
650 struct block_entry *be)
651{
652 struct ref_entry *ref;
653 struct root_entry *re;
654 struct ref_action *ra;
655 struct rb_node *n;
656
657 btrfs_err(fs_info,
658"dumping block entry [%llu %llu], num_refs %llu, metadata %d, from disk %d",
659 be->bytenr, be->len, be->num_refs, be->metadata,
660 be->from_disk);
661
662 for (n = rb_first(&be->refs); n; n = rb_next(n)) {
663 ref = rb_entry(n, struct ref_entry, node);
664 btrfs_err(fs_info,
665" ref root %llu, parent %llu, owner %llu, offset %llu, num_refs %llu",
666 ref->root_objectid, ref->parent, ref->owner,
667 ref->offset, ref->num_refs);
668 }
669
670 for (n = rb_first(&be->roots); n; n = rb_next(n)) {
671 re = rb_entry(n, struct root_entry, node);
672 btrfs_err(fs_info, " root entry %llu, num_refs %llu",
673 re->root_objectid, re->num_refs);
674 }
675
676 list_for_each_entry(ra, &be->actions, list)
677 dump_ref_action(fs_info, ra);
678}
679
680/*
681 * btrfs_ref_tree_mod: called when we modify a ref for a bytenr
682 * @root: the root we are making this modification from.
683 * @bytenr: the bytenr we are modifying.
684 * @num_bytes: number of bytes.
685 * @parent: the parent bytenr.
686 * @ref_root: the original root owner of the bytenr.
687 * @owner: level in the case of metadata, inode in the case of data.
688 * @offset: 0 for metadata, file offset for data.
689 * @action: the action that we are doing, this is the same as the delayed ref
690 * action.
691 *
692 * This will add an action item to the given bytenr and do sanity checks to make
693 * sure we haven't messed something up. If we are making a new allocation and
694 * this block entry has history we will delete all previous actions as long as
695 * our sanity checks pass as they are no longer needed.
696 */
697int btrfs_ref_tree_mod(struct btrfs_root *root, u64 bytenr, u64 num_bytes,
698 u64 parent, u64 ref_root, u64 owner, u64 offset,
699 int action)
700{
701 struct btrfs_fs_info *fs_info = root->fs_info;
702 struct ref_entry *ref = NULL, *exist;
703 struct ref_action *ra = NULL;
704 struct block_entry *be = NULL;
705 struct root_entry *re = NULL;
706 int ret = 0;
707 bool metadata = owner < BTRFS_FIRST_FREE_OBJECTID;
708
709 if (!btrfs_test_opt(root->fs_info, REF_VERIFY))
710 return 0;
711
712 ref = kzalloc(sizeof(struct ref_entry), GFP_NOFS);
713 ra = kmalloc(sizeof(struct ref_action), GFP_NOFS);
714 if (!ra || !ref) {
715 kfree(ref);
716 kfree(ra);
717 ret = -ENOMEM;
718 goto out;
719 }
720
721 if (parent) {
722 ref->parent = parent;
723 } else {
724 ref->root_objectid = ref_root;
725 ref->owner = owner;
726 ref->offset = offset;
727 }
728 ref->num_refs = (action == BTRFS_DROP_DELAYED_REF) ? -1 : 1;
729
730 memcpy(&ra->ref, ref, sizeof(struct ref_entry));
731 /*
732 * Save the extra info from the delayed ref in the ref action to make it
733 * easier to figure out what is happening. The real ref's we add to the
734 * ref tree need to reflect what we save on disk so it matches any
735 * on-disk refs we pre-loaded.
736 */
737 ra->ref.owner = owner;
738 ra->ref.offset = offset;
739 ra->ref.root_objectid = ref_root;
740 __save_stack_trace(ra);
741
742 INIT_LIST_HEAD(&ra->list);
743 ra->action = action;
744 ra->root = root->objectid;
745
746 /*
747 * This is an allocation, preallocate the block_entry in case we haven't
748 * used it before.
749 */
750 ret = -EINVAL;
751 if (action == BTRFS_ADD_DELAYED_EXTENT) {
752 /*
753 * For subvol_create we'll just pass in whatever the parent root
754 * is and the new root objectid, so let's not treat the passed
755 * in root as if it really has a ref for this bytenr.
756 */
757 be = add_block_entry(root->fs_info, bytenr, num_bytes, ref_root);
758 if (IS_ERR(be)) {
759 kfree(ra);
760 ret = PTR_ERR(be);
761 goto out;
762 }
763 be->num_refs++;
764 if (metadata)
765 be->metadata = 1;
766
767 if (be->num_refs != 1) {
768 btrfs_err(fs_info,
769 "re-allocated a block that still has references to it!");
770 dump_block_entry(fs_info, be);
771 dump_ref_action(fs_info, ra);
772 goto out_unlock;
773 }
774
775 while (!list_empty(&be->actions)) {
776 struct ref_action *tmp;
777
778 tmp = list_first_entry(&be->actions, struct ref_action,
779 list);
780 list_del(&tmp->list);
781 kfree(tmp);
782 }
783 } else {
784 struct root_entry *tmp;
785
786 if (!parent) {
787 re = kmalloc(sizeof(struct root_entry), GFP_NOFS);
788 if (!re) {
789 kfree(ref);
790 kfree(ra);
791 ret = -ENOMEM;
792 goto out;
793 }
794 /*
795 * This is the root that is modifying us, so it's the
796 * one we want to lookup below when we modify the
797 * re->num_refs.
798 */
799 ref_root = root->objectid;
800 re->root_objectid = root->objectid;
801 re->num_refs = 0;
802 }
803
804 spin_lock(&root->fs_info->ref_verify_lock);
805 be = lookup_block_entry(&root->fs_info->block_tree, bytenr);
806 if (!be) {
807 btrfs_err(fs_info,
808"trying to do action %d to bytenr %llu num_bytes %llu but there is no existing entry!",
809 action, (unsigned long long)bytenr,
810 (unsigned long long)num_bytes);
811 dump_ref_action(fs_info, ra);
812 kfree(ref);
813 kfree(ra);
814 goto out_unlock;
815 }
816
817 if (!parent) {
818 tmp = insert_root_entry(&be->roots, re);
819 if (tmp) {
820 kfree(re);
821 re = tmp;
822 }
823 }
824 }
825
826 exist = insert_ref_entry(&be->refs, ref);
827 if (exist) {
828 if (action == BTRFS_DROP_DELAYED_REF) {
829 if (exist->num_refs == 0) {
830 btrfs_err(fs_info,
831"dropping a ref for a existing root that doesn't have a ref on the block");
832 dump_block_entry(fs_info, be);
833 dump_ref_action(fs_info, ra);
834 kfree(ra);
835 goto out_unlock;
836 }
837 exist->num_refs--;
838 if (exist->num_refs == 0) {
839 rb_erase(&exist->node, &be->refs);
840 kfree(exist);
841 }
842 } else if (!be->metadata) {
843 exist->num_refs++;
844 } else {
845 btrfs_err(fs_info,
846"attempting to add another ref for an existing ref on a tree block");
847 dump_block_entry(fs_info, be);
848 dump_ref_action(fs_info, ra);
849 kfree(ra);
850 goto out_unlock;
851 }
852 kfree(ref);
853 } else {
854 if (action == BTRFS_DROP_DELAYED_REF) {
855 btrfs_err(fs_info,
856"dropping a ref for a root that doesn't have a ref on the block");
857 dump_block_entry(fs_info, be);
858 dump_ref_action(fs_info, ra);
859 kfree(ra);
860 goto out_unlock;
861 }
862 }
863
864 if (!parent && !re) {
865 re = lookup_root_entry(&be->roots, ref_root);
866 if (!re) {
867 /*
868 * This shouldn't happen because we will add our re
869 * above when we lookup the be with !parent, but just in
870 * case catch this case so we don't panic because I
871 * didn't thik of some other corner case.
872 */
873 btrfs_err(fs_info, "failed to find root %llu for %llu",
874 root->objectid, be->bytenr);
875 dump_block_entry(fs_info, be);
876 dump_ref_action(fs_info, ra);
877 kfree(ra);
878 goto out_unlock;
879 }
880 }
881 if (action == BTRFS_DROP_DELAYED_REF) {
882 if (re)
883 re->num_refs--;
884 be->num_refs--;
885 } else if (action == BTRFS_ADD_DELAYED_REF) {
886 be->num_refs++;
887 if (re)
888 re->num_refs++;
889 }
890 list_add_tail(&ra->list, &be->actions);
891 ret = 0;
892out_unlock:
893 spin_unlock(&root->fs_info->ref_verify_lock);
894out:
895 if (ret)
896 btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
897 return ret;
898}
899
900/* Free up the ref cache */
901void btrfs_free_ref_cache(struct btrfs_fs_info *fs_info)
902{
903 struct block_entry *be;
904 struct rb_node *n;
905
906 if (!btrfs_test_opt(fs_info, REF_VERIFY))
907 return;
908
909 spin_lock(&fs_info->ref_verify_lock);
910 while ((n = rb_first(&fs_info->block_tree))) {
911 be = rb_entry(n, struct block_entry, node);
912 rb_erase(&be->node, &fs_info->block_tree);
913 free_block_entry(be);
914 cond_resched_lock(&fs_info->ref_verify_lock);
915 }
916 spin_unlock(&fs_info->ref_verify_lock);
917}
918
919void btrfs_free_ref_tree_range(struct btrfs_fs_info *fs_info, u64 start,
920 u64 len)
921{
922 struct block_entry *be = NULL, *entry;
923 struct rb_node *n;
924
925 if (!btrfs_test_opt(fs_info, REF_VERIFY))
926 return;
927
928 spin_lock(&fs_info->ref_verify_lock);
929 n = fs_info->block_tree.rb_node;
930 while (n) {
931 entry = rb_entry(n, struct block_entry, node);
932 if (entry->bytenr < start) {
933 n = n->rb_right;
934 } else if (entry->bytenr > start) {
935 n = n->rb_left;
936 } else {
937 be = entry;
938 break;
939 }
940 /* We want to get as close to start as possible */
941 if (be == NULL ||
942 (entry->bytenr < start && be->bytenr > start) ||
943 (entry->bytenr < start && entry->bytenr > be->bytenr))
944 be = entry;
945 }
946
947 /*
948 * Could have an empty block group, maybe have something to check for
949 * this case to verify we were actually empty?
950 */
951 if (!be) {
952 spin_unlock(&fs_info->ref_verify_lock);
953 return;
954 }
955
956 n = &be->node;
957 while (n) {
958 be = rb_entry(n, struct block_entry, node);
959 n = rb_next(n);
960 if (be->bytenr < start && be->bytenr + be->len > start) {
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 continue;
966 }
967 if (be->bytenr < start)
968 continue;
969 if (be->bytenr >= start + len)
970 break;
971 if (be->bytenr + be->len > start + len) {
972 btrfs_err(fs_info,
973 "block entry overlaps a block group [%llu,%llu]!",
974 start, len);
975 dump_block_entry(fs_info, be);
976 }
977 rb_erase(&be->node, &fs_info->block_tree);
978 free_block_entry(be);
979 }
980 spin_unlock(&fs_info->ref_verify_lock);
981}
982
983/* Walk down all roots and build the ref tree, meant to be called at mount */
984int btrfs_build_ref_tree(struct btrfs_fs_info *fs_info)
985{
986 struct btrfs_path *path;
987 struct btrfs_root *root;
988 struct extent_buffer *eb;
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 eb = btrfs_read_lock_root_node(fs_info->extent_root);
1000 btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
1001 level = btrfs_header_level(eb);
1002 path->nodes[level] = eb;
1003 path->slots[level] = 0;
1004 path->locks[level] = BTRFS_READ_LOCK_BLOCKING;
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(fs_info->extent_root, path, level,
1014 &bytenr, &num_bytes);
1015 if (ret)
1016 break;
1017 ret = walk_up_tree(root, path, &level);
1018 if (ret < 0)
1019 break;
1020 if (ret > 0) {
1021 ret = 0;
1022 break;
1023 }
1024 }
1025 if (ret) {
1026 btrfs_clear_opt(fs_info->mount_opt, REF_VERIFY);
1027 btrfs_free_ref_cache(fs_info);
1028 }
1029 btrfs_free_path(path);
1030 return ret;
1031}
generated by cgit v1.2.2 (git 2.25.0) at 2025-04-25 05:44:55 -0400