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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2009 Oracle. All rights reserved.
4 */
5
6#include <linux/sched.h>
7#include <linux/pagemap.h>
8#include <linux/writeback.h>
9#include <linux/blkdev.h>
10#include <linux/rbtree.h>
11#include <linux/slab.h>
12#include <linux/error-injection.h>
13#include "ctree.h"
14#include "disk-io.h"
15#include "transaction.h"
16#include "volumes.h"
17#include "locking.h"
18#include "btrfs_inode.h"
19#include "async-thread.h"
20#include "free-space-cache.h"
21#include "qgroup.h"
22#include "print-tree.h"
23#include "delalloc-space.h"
24#include "block-group.h"
25#include "backref.h"
26#include "misc.h"
27#include "subpage.h"
28#include "zoned.h"
29#include "inode-item.h"
30#include "space-info.h"
31#include "fs.h"
32#include "accessors.h"
33#include "extent-tree.h"
34#include "root-tree.h"
35#include "file-item.h"
36#include "relocation.h"
37#include "super.h"
38#include "tree-checker.h"
39
40/*
41 * Relocation overview
42 *
43 * [What does relocation do]
44 *
45 * The objective of relocation is to relocate all extents of the target block
46 * group to other block groups.
47 * This is utilized by resize (shrink only), profile converting, compacting
48 * space, or balance routine to spread chunks over devices.
49 *
50 * Before | After
51 * ------------------------------------------------------------------
52 * BG A: 10 data extents | BG A: deleted
53 * BG B: 2 data extents | BG B: 10 data extents (2 old + 8 relocated)
54 * BG C: 1 extents | BG C: 3 data extents (1 old + 2 relocated)
55 *
56 * [How does relocation work]
57 *
58 * 1. Mark the target block group read-only
59 * New extents won't be allocated from the target block group.
60 *
61 * 2.1 Record each extent in the target block group
62 * To build a proper map of extents to be relocated.
63 *
64 * 2.2 Build data reloc tree and reloc trees
65 * Data reloc tree will contain an inode, recording all newly relocated
66 * data extents.
67 * There will be only one data reloc tree for one data block group.
68 *
69 * Reloc tree will be a special snapshot of its source tree, containing
70 * relocated tree blocks.
71 * Each tree referring to a tree block in target block group will get its
72 * reloc tree built.
73 *
74 * 2.3 Swap source tree with its corresponding reloc tree
75 * Each involved tree only refers to new extents after swap.
76 *
77 * 3. Cleanup reloc trees and data reloc tree.
78 * As old extents in the target block group are still referenced by reloc
79 * trees, we need to clean them up before really freeing the target block
80 * group.
81 *
82 * The main complexity is in steps 2.2 and 2.3.
83 *
84 * The entry point of relocation is relocate_block_group() function.
85 */
86
87#define RELOCATION_RESERVED_NODES 256
88/*
89 * map address of tree root to tree
90 */
91struct mapping_node {
92 struct {
93 struct rb_node rb_node;
94 u64 bytenr;
95 }; /* Use rb_simle_node for search/insert */
96 void *data;
97};
98
99struct mapping_tree {
100 struct rb_root rb_root;
101 spinlock_t lock;
102};
103
104/*
105 * present a tree block to process
106 */
107struct tree_block {
108 struct {
109 struct rb_node rb_node;
110 u64 bytenr;
111 }; /* Use rb_simple_node for search/insert */
112 u64 owner;
113 struct btrfs_key key;
114 unsigned int level:8;
115 unsigned int key_ready:1;
116};
117
118#define MAX_EXTENTS 128
119
120struct file_extent_cluster {
121 u64 start;
122 u64 end;
123 u64 boundary[MAX_EXTENTS];
124 unsigned int nr;
125};
126
127struct reloc_control {
128 /* block group to relocate */
129 struct btrfs_block_group *block_group;
130 /* extent tree */
131 struct btrfs_root *extent_root;
132 /* inode for moving data */
133 struct inode *data_inode;
134
135 struct btrfs_block_rsv *block_rsv;
136
137 struct btrfs_backref_cache backref_cache;
138
139 struct file_extent_cluster cluster;
140 /* tree blocks have been processed */
141 struct extent_io_tree processed_blocks;
142 /* map start of tree root to corresponding reloc tree */
143 struct mapping_tree reloc_root_tree;
144 /* list of reloc trees */
145 struct list_head reloc_roots;
146 /* list of subvolume trees that get relocated */
147 struct list_head dirty_subvol_roots;
148 /* size of metadata reservation for merging reloc trees */
149 u64 merging_rsv_size;
150 /* size of relocated tree nodes */
151 u64 nodes_relocated;
152 /* reserved size for block group relocation*/
153 u64 reserved_bytes;
154
155 u64 search_start;
156 u64 extents_found;
157
158 unsigned int stage:8;
159 unsigned int create_reloc_tree:1;
160 unsigned int merge_reloc_tree:1;
161 unsigned int found_file_extent:1;
162};
163
164/* stages of data relocation */
165#define MOVE_DATA_EXTENTS 0
166#define UPDATE_DATA_PTRS 1
167
168static void mark_block_processed(struct reloc_control *rc,
169 struct btrfs_backref_node *node)
170{
171 u32 blocksize;
172
173 if (node->level == 0 ||
174 in_range(node->bytenr, rc->block_group->start,
175 rc->block_group->length)) {
176 blocksize = rc->extent_root->fs_info->nodesize;
177 set_extent_bits(&rc->processed_blocks, node->bytenr,
178 node->bytenr + blocksize - 1, EXTENT_DIRTY);
179 }
180 node->processed = 1;
181}
182
183
184static void mapping_tree_init(struct mapping_tree *tree)
185{
186 tree->rb_root = RB_ROOT;
187 spin_lock_init(&tree->lock);
188}
189
190/*
191 * walk up backref nodes until reach node presents tree root
192 */
193static struct btrfs_backref_node *walk_up_backref(
194 struct btrfs_backref_node *node,
195 struct btrfs_backref_edge *edges[], int *index)
196{
197 struct btrfs_backref_edge *edge;
198 int idx = *index;
199
200 while (!list_empty(&node->upper)) {
201 edge = list_entry(node->upper.next,
202 struct btrfs_backref_edge, list[LOWER]);
203 edges[idx++] = edge;
204 node = edge->node[UPPER];
205 }
206 BUG_ON(node->detached);
207 *index = idx;
208 return node;
209}
210
211/*
212 * walk down backref nodes to find start of next reference path
213 */
214static struct btrfs_backref_node *walk_down_backref(
215 struct btrfs_backref_edge *edges[], int *index)
216{
217 struct btrfs_backref_edge *edge;
218 struct btrfs_backref_node *lower;
219 int idx = *index;
220
221 while (idx > 0) {
222 edge = edges[idx - 1];
223 lower = edge->node[LOWER];
224 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
225 idx--;
226 continue;
227 }
228 edge = list_entry(edge->list[LOWER].next,
229 struct btrfs_backref_edge, list[LOWER]);
230 edges[idx - 1] = edge;
231 *index = idx;
232 return edge->node[UPPER];
233 }
234 *index = 0;
235 return NULL;
236}
237
238static void update_backref_node(struct btrfs_backref_cache *cache,
239 struct btrfs_backref_node *node, u64 bytenr)
240{
241 struct rb_node *rb_node;
242 rb_erase(&node->rb_node, &cache->rb_root);
243 node->bytenr = bytenr;
244 rb_node = rb_simple_insert(&cache->rb_root, node->bytenr, &node->rb_node);
245 if (rb_node)
246 btrfs_backref_panic(cache->fs_info, bytenr, -EEXIST);
247}
248
249/*
250 * update backref cache after a transaction commit
251 */
252static int update_backref_cache(struct btrfs_trans_handle *trans,
253 struct btrfs_backref_cache *cache)
254{
255 struct btrfs_backref_node *node;
256 int level = 0;
257
258 if (cache->last_trans == 0) {
259 cache->last_trans = trans->transid;
260 return 0;
261 }
262
263 if (cache->last_trans == trans->transid)
264 return 0;
265
266 /*
267 * detached nodes are used to avoid unnecessary backref
268 * lookup. transaction commit changes the extent tree.
269 * so the detached nodes are no longer useful.
270 */
271 while (!list_empty(&cache->detached)) {
272 node = list_entry(cache->detached.next,
273 struct btrfs_backref_node, list);
274 btrfs_backref_cleanup_node(cache, node);
275 }
276
277 while (!list_empty(&cache->changed)) {
278 node = list_entry(cache->changed.next,
279 struct btrfs_backref_node, list);
280 list_del_init(&node->list);
281 BUG_ON(node->pending);
282 update_backref_node(cache, node, node->new_bytenr);
283 }
284
285 /*
286 * some nodes can be left in the pending list if there were
287 * errors during processing the pending nodes.
288 */
289 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
290 list_for_each_entry(node, &cache->pending[level], list) {
291 BUG_ON(!node->pending);
292 if (node->bytenr == node->new_bytenr)
293 continue;
294 update_backref_node(cache, node, node->new_bytenr);
295 }
296 }
297
298 cache->last_trans = 0;
299 return 1;
300}
301
302static bool reloc_root_is_dead(struct btrfs_root *root)
303{
304 /*
305 * Pair with set_bit/clear_bit in clean_dirty_subvols and
306 * btrfs_update_reloc_root. We need to see the updated bit before
307 * trying to access reloc_root
308 */
309 smp_rmb();
310 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state))
311 return true;
312 return false;
313}
314
315/*
316 * Check if this subvolume tree has valid reloc tree.
317 *
318 * Reloc tree after swap is considered dead, thus not considered as valid.
319 * This is enough for most callers, as they don't distinguish dead reloc root
320 * from no reloc root. But btrfs_should_ignore_reloc_root() below is a
321 * special case.
322 */
323static bool have_reloc_root(struct btrfs_root *root)
324{
325 if (reloc_root_is_dead(root))
326 return false;
327 if (!root->reloc_root)
328 return false;
329 return true;
330}
331
332int btrfs_should_ignore_reloc_root(struct btrfs_root *root)
333{
334 struct btrfs_root *reloc_root;
335
336 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
337 return 0;
338
339 /* This root has been merged with its reloc tree, we can ignore it */
340 if (reloc_root_is_dead(root))
341 return 1;
342
343 reloc_root = root->reloc_root;
344 if (!reloc_root)
345 return 0;
346
347 if (btrfs_header_generation(reloc_root->commit_root) ==
348 root->fs_info->running_transaction->transid)
349 return 0;
350 /*
351 * if there is reloc tree and it was created in previous
352 * transaction backref lookup can find the reloc tree,
353 * so backref node for the fs tree root is useless for
354 * relocation.
355 */
356 return 1;
357}
358
359/*
360 * find reloc tree by address of tree root
361 */
362struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr)
363{
364 struct reloc_control *rc = fs_info->reloc_ctl;
365 struct rb_node *rb_node;
366 struct mapping_node *node;
367 struct btrfs_root *root = NULL;
368
369 ASSERT(rc);
370 spin_lock(&rc->reloc_root_tree.lock);
371 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, bytenr);
372 if (rb_node) {
373 node = rb_entry(rb_node, struct mapping_node, rb_node);
374 root = node->data;
375 }
376 spin_unlock(&rc->reloc_root_tree.lock);
377 return btrfs_grab_root(root);
378}
379
380/*
381 * For useless nodes, do two major clean ups:
382 *
383 * - Cleanup the children edges and nodes
384 * If child node is also orphan (no parent) during cleanup, then the child
385 * node will also be cleaned up.
386 *
387 * - Freeing up leaves (level 0), keeps nodes detached
388 * For nodes, the node is still cached as "detached"
389 *
390 * Return false if @node is not in the @useless_nodes list.
391 * Return true if @node is in the @useless_nodes list.
392 */
393static bool handle_useless_nodes(struct reloc_control *rc,
394 struct btrfs_backref_node *node)
395{
396 struct btrfs_backref_cache *cache = &rc->backref_cache;
397 struct list_head *useless_node = &cache->useless_node;
398 bool ret = false;
399
400 while (!list_empty(useless_node)) {
401 struct btrfs_backref_node *cur;
402
403 cur = list_first_entry(useless_node, struct btrfs_backref_node,
404 list);
405 list_del_init(&cur->list);
406
407 /* Only tree root nodes can be added to @useless_nodes */
408 ASSERT(list_empty(&cur->upper));
409
410 if (cur == node)
411 ret = true;
412
413 /* The node is the lowest node */
414 if (cur->lowest) {
415 list_del_init(&cur->lower);
416 cur->lowest = 0;
417 }
418
419 /* Cleanup the lower edges */
420 while (!list_empty(&cur->lower)) {
421 struct btrfs_backref_edge *edge;
422 struct btrfs_backref_node *lower;
423
424 edge = list_entry(cur->lower.next,
425 struct btrfs_backref_edge, list[UPPER]);
426 list_del(&edge->list[UPPER]);
427 list_del(&edge->list[LOWER]);
428 lower = edge->node[LOWER];
429 btrfs_backref_free_edge(cache, edge);
430
431 /* Child node is also orphan, queue for cleanup */
432 if (list_empty(&lower->upper))
433 list_add(&lower->list, useless_node);
434 }
435 /* Mark this block processed for relocation */
436 mark_block_processed(rc, cur);
437
438 /*
439 * Backref nodes for tree leaves are deleted from the cache.
440 * Backref nodes for upper level tree blocks are left in the
441 * cache to avoid unnecessary backref lookup.
442 */
443 if (cur->level > 0) {
444 list_add(&cur->list, &cache->detached);
445 cur->detached = 1;
446 } else {
447 rb_erase(&cur->rb_node, &cache->rb_root);
448 btrfs_backref_free_node(cache, cur);
449 }
450 }
451 return ret;
452}
453
454/*
455 * Build backref tree for a given tree block. Root of the backref tree
456 * corresponds the tree block, leaves of the backref tree correspond roots of
457 * b-trees that reference the tree block.
458 *
459 * The basic idea of this function is check backrefs of a given block to find
460 * upper level blocks that reference the block, and then check backrefs of
461 * these upper level blocks recursively. The recursion stops when tree root is
462 * reached or backrefs for the block is cached.
463 *
464 * NOTE: if we find that backrefs for a block are cached, we know backrefs for
465 * all upper level blocks that directly/indirectly reference the block are also
466 * cached.
467 */
468static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
469 struct reloc_control *rc, struct btrfs_key *node_key,
470 int level, u64 bytenr)
471{
472 struct btrfs_backref_iter *iter;
473 struct btrfs_backref_cache *cache = &rc->backref_cache;
474 /* For searching parent of TREE_BLOCK_REF */
475 struct btrfs_path *path;
476 struct btrfs_backref_node *cur;
477 struct btrfs_backref_node *node = NULL;
478 struct btrfs_backref_edge *edge;
479 int ret;
480 int err = 0;
481
482 iter = btrfs_backref_iter_alloc(rc->extent_root->fs_info);
483 if (!iter)
484 return ERR_PTR(-ENOMEM);
485 path = btrfs_alloc_path();
486 if (!path) {
487 err = -ENOMEM;
488 goto out;
489 }
490
491 node = btrfs_backref_alloc_node(cache, bytenr, level);
492 if (!node) {
493 err = -ENOMEM;
494 goto out;
495 }
496
497 node->lowest = 1;
498 cur = node;
499
500 /* Breadth-first search to build backref cache */
501 do {
502 ret = btrfs_backref_add_tree_node(cache, path, iter, node_key,
503 cur);
504 if (ret < 0) {
505 err = ret;
506 goto out;
507 }
508 edge = list_first_entry_or_null(&cache->pending_edge,
509 struct btrfs_backref_edge, list[UPPER]);
510 /*
511 * The pending list isn't empty, take the first block to
512 * process
513 */
514 if (edge) {
515 list_del_init(&edge->list[UPPER]);
516 cur = edge->node[UPPER];
517 }
518 } while (edge);
519
520 /* Finish the upper linkage of newly added edges/nodes */
521 ret = btrfs_backref_finish_upper_links(cache, node);
522 if (ret < 0) {
523 err = ret;
524 goto out;
525 }
526
527 if (handle_useless_nodes(rc, node))
528 node = NULL;
529out:
530 btrfs_backref_iter_free(iter);
531 btrfs_free_path(path);
532 if (err) {
533 btrfs_backref_error_cleanup(cache, node);
534 return ERR_PTR(err);
535 }
536 ASSERT(!node || !node->detached);
537 ASSERT(list_empty(&cache->useless_node) &&
538 list_empty(&cache->pending_edge));
539 return node;
540}
541
542/*
543 * helper to add backref node for the newly created snapshot.
544 * the backref node is created by cloning backref node that
545 * corresponds to root of source tree
546 */
547static int clone_backref_node(struct btrfs_trans_handle *trans,
548 struct reloc_control *rc,
549 struct btrfs_root *src,
550 struct btrfs_root *dest)
551{
552 struct btrfs_root *reloc_root = src->reloc_root;
553 struct btrfs_backref_cache *cache = &rc->backref_cache;
554 struct btrfs_backref_node *node = NULL;
555 struct btrfs_backref_node *new_node;
556 struct btrfs_backref_edge *edge;
557 struct btrfs_backref_edge *new_edge;
558 struct rb_node *rb_node;
559
560 if (cache->last_trans > 0)
561 update_backref_cache(trans, cache);
562
563 rb_node = rb_simple_search(&cache->rb_root, src->commit_root->start);
564 if (rb_node) {
565 node = rb_entry(rb_node, struct btrfs_backref_node, rb_node);
566 if (node->detached)
567 node = NULL;
568 else
569 BUG_ON(node->new_bytenr != reloc_root->node->start);
570 }
571
572 if (!node) {
573 rb_node = rb_simple_search(&cache->rb_root,
574 reloc_root->commit_root->start);
575 if (rb_node) {
576 node = rb_entry(rb_node, struct btrfs_backref_node,
577 rb_node);
578 BUG_ON(node->detached);
579 }
580 }
581
582 if (!node)
583 return 0;
584
585 new_node = btrfs_backref_alloc_node(cache, dest->node->start,
586 node->level);
587 if (!new_node)
588 return -ENOMEM;
589
590 new_node->lowest = node->lowest;
591 new_node->checked = 1;
592 new_node->root = btrfs_grab_root(dest);
593 ASSERT(new_node->root);
594
595 if (!node->lowest) {
596 list_for_each_entry(edge, &node->lower, list[UPPER]) {
597 new_edge = btrfs_backref_alloc_edge(cache);
598 if (!new_edge)
599 goto fail;
600
601 btrfs_backref_link_edge(new_edge, edge->node[LOWER],
602 new_node, LINK_UPPER);
603 }
604 } else {
605 list_add_tail(&new_node->lower, &cache->leaves);
606 }
607
608 rb_node = rb_simple_insert(&cache->rb_root, new_node->bytenr,
609 &new_node->rb_node);
610 if (rb_node)
611 btrfs_backref_panic(trans->fs_info, new_node->bytenr, -EEXIST);
612
613 if (!new_node->lowest) {
614 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
615 list_add_tail(&new_edge->list[LOWER],
616 &new_edge->node[LOWER]->upper);
617 }
618 }
619 return 0;
620fail:
621 while (!list_empty(&new_node->lower)) {
622 new_edge = list_entry(new_node->lower.next,
623 struct btrfs_backref_edge, list[UPPER]);
624 list_del(&new_edge->list[UPPER]);
625 btrfs_backref_free_edge(cache, new_edge);
626 }
627 btrfs_backref_free_node(cache, new_node);
628 return -ENOMEM;
629}
630
631/*
632 * helper to add 'address of tree root -> reloc tree' mapping
633 */
634static int __must_check __add_reloc_root(struct btrfs_root *root)
635{
636 struct btrfs_fs_info *fs_info = root->fs_info;
637 struct rb_node *rb_node;
638 struct mapping_node *node;
639 struct reloc_control *rc = fs_info->reloc_ctl;
640
641 node = kmalloc(sizeof(*node), GFP_NOFS);
642 if (!node)
643 return -ENOMEM;
644
645 node->bytenr = root->commit_root->start;
646 node->data = root;
647
648 spin_lock(&rc->reloc_root_tree.lock);
649 rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
650 node->bytenr, &node->rb_node);
651 spin_unlock(&rc->reloc_root_tree.lock);
652 if (rb_node) {
653 btrfs_err(fs_info,
654 "Duplicate root found for start=%llu while inserting into relocation tree",
655 node->bytenr);
656 return -EEXIST;
657 }
658
659 list_add_tail(&root->root_list, &rc->reloc_roots);
660 return 0;
661}
662
663/*
664 * helper to delete the 'address of tree root -> reloc tree'
665 * mapping
666 */
667static void __del_reloc_root(struct btrfs_root *root)
668{
669 struct btrfs_fs_info *fs_info = root->fs_info;
670 struct rb_node *rb_node;
671 struct mapping_node *node = NULL;
672 struct reloc_control *rc = fs_info->reloc_ctl;
673 bool put_ref = false;
674
675 if (rc && root->node) {
676 spin_lock(&rc->reloc_root_tree.lock);
677 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
678 root->commit_root->start);
679 if (rb_node) {
680 node = rb_entry(rb_node, struct mapping_node, rb_node);
681 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
682 RB_CLEAR_NODE(&node->rb_node);
683 }
684 spin_unlock(&rc->reloc_root_tree.lock);
685 ASSERT(!node || (struct btrfs_root *)node->data == root);
686 }
687
688 /*
689 * We only put the reloc root here if it's on the list. There's a lot
690 * of places where the pattern is to splice the rc->reloc_roots, process
691 * the reloc roots, and then add the reloc root back onto
692 * rc->reloc_roots. If we call __del_reloc_root while it's off of the
693 * list we don't want the reference being dropped, because the guy
694 * messing with the list is in charge of the reference.
695 */
696 spin_lock(&fs_info->trans_lock);
697 if (!list_empty(&root->root_list)) {
698 put_ref = true;
699 list_del_init(&root->root_list);
700 }
701 spin_unlock(&fs_info->trans_lock);
702 if (put_ref)
703 btrfs_put_root(root);
704 kfree(node);
705}
706
707/*
708 * helper to update the 'address of tree root -> reloc tree'
709 * mapping
710 */
711static int __update_reloc_root(struct btrfs_root *root)
712{
713 struct btrfs_fs_info *fs_info = root->fs_info;
714 struct rb_node *rb_node;
715 struct mapping_node *node = NULL;
716 struct reloc_control *rc = fs_info->reloc_ctl;
717
718 spin_lock(&rc->reloc_root_tree.lock);
719 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
720 root->commit_root->start);
721 if (rb_node) {
722 node = rb_entry(rb_node, struct mapping_node, rb_node);
723 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
724 }
725 spin_unlock(&rc->reloc_root_tree.lock);
726
727 if (!node)
728 return 0;
729 BUG_ON((struct btrfs_root *)node->data != root);
730
731 spin_lock(&rc->reloc_root_tree.lock);
732 node->bytenr = root->node->start;
733 rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
734 node->bytenr, &node->rb_node);
735 spin_unlock(&rc->reloc_root_tree.lock);
736 if (rb_node)
737 btrfs_backref_panic(fs_info, node->bytenr, -EEXIST);
738 return 0;
739}
740
741static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
742 struct btrfs_root *root, u64 objectid)
743{
744 struct btrfs_fs_info *fs_info = root->fs_info;
745 struct btrfs_root *reloc_root;
746 struct extent_buffer *eb;
747 struct btrfs_root_item *root_item;
748 struct btrfs_key root_key;
749 int ret = 0;
750 bool must_abort = false;
751
752 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
753 if (!root_item)
754 return ERR_PTR(-ENOMEM);
755
756 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
757 root_key.type = BTRFS_ROOT_ITEM_KEY;
758 root_key.offset = objectid;
759
760 if (root->root_key.objectid == objectid) {
761 u64 commit_root_gen;
762
763 /* called by btrfs_init_reloc_root */
764 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
765 BTRFS_TREE_RELOC_OBJECTID);
766 if (ret)
767 goto fail;
768
769 /*
770 * Set the last_snapshot field to the generation of the commit
771 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
772 * correctly (returns true) when the relocation root is created
773 * either inside the critical section of a transaction commit
774 * (through transaction.c:qgroup_account_snapshot()) and when
775 * it's created before the transaction commit is started.
776 */
777 commit_root_gen = btrfs_header_generation(root->commit_root);
778 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
779 } else {
780 /*
781 * called by btrfs_reloc_post_snapshot_hook.
782 * the source tree is a reloc tree, all tree blocks
783 * modified after it was created have RELOC flag
784 * set in their headers. so it's OK to not update
785 * the 'last_snapshot'.
786 */
787 ret = btrfs_copy_root(trans, root, root->node, &eb,
788 BTRFS_TREE_RELOC_OBJECTID);
789 if (ret)
790 goto fail;
791 }
792
793 /*
794 * We have changed references at this point, we must abort the
795 * transaction if anything fails.
796 */
797 must_abort = true;
798
799 memcpy(root_item, &root->root_item, sizeof(*root_item));
800 btrfs_set_root_bytenr(root_item, eb->start);
801 btrfs_set_root_level(root_item, btrfs_header_level(eb));
802 btrfs_set_root_generation(root_item, trans->transid);
803
804 if (root->root_key.objectid == objectid) {
805 btrfs_set_root_refs(root_item, 0);
806 memset(&root_item->drop_progress, 0,
807 sizeof(struct btrfs_disk_key));
808 btrfs_set_root_drop_level(root_item, 0);
809 }
810
811 btrfs_tree_unlock(eb);
812 free_extent_buffer(eb);
813
814 ret = btrfs_insert_root(trans, fs_info->tree_root,
815 &root_key, root_item);
816 if (ret)
817 goto fail;
818
819 kfree(root_item);
820
821 reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key);
822 if (IS_ERR(reloc_root)) {
823 ret = PTR_ERR(reloc_root);
824 goto abort;
825 }
826 set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
827 reloc_root->last_trans = trans->transid;
828 return reloc_root;
829fail:
830 kfree(root_item);
831abort:
832 if (must_abort)
833 btrfs_abort_transaction(trans, ret);
834 return ERR_PTR(ret);
835}
836
837/*
838 * create reloc tree for a given fs tree. reloc tree is just a
839 * snapshot of the fs tree with special root objectid.
840 *
841 * The reloc_root comes out of here with two references, one for
842 * root->reloc_root, and another for being on the rc->reloc_roots list.
843 */
844int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
845 struct btrfs_root *root)
846{
847 struct btrfs_fs_info *fs_info = root->fs_info;
848 struct btrfs_root *reloc_root;
849 struct reloc_control *rc = fs_info->reloc_ctl;
850 struct btrfs_block_rsv *rsv;
851 int clear_rsv = 0;
852 int ret;
853
854 if (!rc)
855 return 0;
856
857 /*
858 * The subvolume has reloc tree but the swap is finished, no need to
859 * create/update the dead reloc tree
860 */
861 if (reloc_root_is_dead(root))
862 return 0;
863
864 /*
865 * This is subtle but important. We do not do
866 * record_root_in_transaction for reloc roots, instead we record their
867 * corresponding fs root, and then here we update the last trans for the
868 * reloc root. This means that we have to do this for the entire life
869 * of the reloc root, regardless of which stage of the relocation we are
870 * in.
871 */
872 if (root->reloc_root) {
873 reloc_root = root->reloc_root;
874 reloc_root->last_trans = trans->transid;
875 return 0;
876 }
877
878 /*
879 * We are merging reloc roots, we do not need new reloc trees. Also
880 * reloc trees never need their own reloc tree.
881 */
882 if (!rc->create_reloc_tree ||
883 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
884 return 0;
885
886 if (!trans->reloc_reserved) {
887 rsv = trans->block_rsv;
888 trans->block_rsv = rc->block_rsv;
889 clear_rsv = 1;
890 }
891 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
892 if (clear_rsv)
893 trans->block_rsv = rsv;
894 if (IS_ERR(reloc_root))
895 return PTR_ERR(reloc_root);
896
897 ret = __add_reloc_root(reloc_root);
898 ASSERT(ret != -EEXIST);
899 if (ret) {
900 /* Pairs with create_reloc_root */
901 btrfs_put_root(reloc_root);
902 return ret;
903 }
904 root->reloc_root = btrfs_grab_root(reloc_root);
905 return 0;
906}
907
908/*
909 * update root item of reloc tree
910 */
911int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
912 struct btrfs_root *root)
913{
914 struct btrfs_fs_info *fs_info = root->fs_info;
915 struct btrfs_root *reloc_root;
916 struct btrfs_root_item *root_item;
917 int ret;
918
919 if (!have_reloc_root(root))
920 return 0;
921
922 reloc_root = root->reloc_root;
923 root_item = &reloc_root->root_item;
924
925 /*
926 * We are probably ok here, but __del_reloc_root() will drop its ref of
927 * the root. We have the ref for root->reloc_root, but just in case
928 * hold it while we update the reloc root.
929 */
930 btrfs_grab_root(reloc_root);
931
932 /* root->reloc_root will stay until current relocation finished */
933 if (fs_info->reloc_ctl->merge_reloc_tree &&
934 btrfs_root_refs(root_item) == 0) {
935 set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
936 /*
937 * Mark the tree as dead before we change reloc_root so
938 * have_reloc_root will not touch it from now on.
939 */
940 smp_wmb();
941 __del_reloc_root(reloc_root);
942 }
943
944 if (reloc_root->commit_root != reloc_root->node) {
945 __update_reloc_root(reloc_root);
946 btrfs_set_root_node(root_item, reloc_root->node);
947 free_extent_buffer(reloc_root->commit_root);
948 reloc_root->commit_root = btrfs_root_node(reloc_root);
949 }
950
951 ret = btrfs_update_root(trans, fs_info->tree_root,
952 &reloc_root->root_key, root_item);
953 btrfs_put_root(reloc_root);
954 return ret;
955}
956
957/*
958 * helper to find first cached inode with inode number >= objectid
959 * in a subvolume
960 */
961static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
962{
963 struct rb_node *node;
964 struct rb_node *prev;
965 struct btrfs_inode *entry;
966 struct inode *inode;
967
968 spin_lock(&root->inode_lock);
969again:
970 node = root->inode_tree.rb_node;
971 prev = NULL;
972 while (node) {
973 prev = node;
974 entry = rb_entry(node, struct btrfs_inode, rb_node);
975
976 if (objectid < btrfs_ino(entry))
977 node = node->rb_left;
978 else if (objectid > btrfs_ino(entry))
979 node = node->rb_right;
980 else
981 break;
982 }
983 if (!node) {
984 while (prev) {
985 entry = rb_entry(prev, struct btrfs_inode, rb_node);
986 if (objectid <= btrfs_ino(entry)) {
987 node = prev;
988 break;
989 }
990 prev = rb_next(prev);
991 }
992 }
993 while (node) {
994 entry = rb_entry(node, struct btrfs_inode, rb_node);
995 inode = igrab(&entry->vfs_inode);
996 if (inode) {
997 spin_unlock(&root->inode_lock);
998 return inode;
999 }
1000
1001 objectid = btrfs_ino(entry) + 1;
1002 if (cond_resched_lock(&root->inode_lock))
1003 goto again;
1004
1005 node = rb_next(node);
1006 }
1007 spin_unlock(&root->inode_lock);
1008 return NULL;
1009}
1010
1011/*
1012 * get new location of data
1013 */
1014static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1015 u64 bytenr, u64 num_bytes)
1016{
1017 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1018 struct btrfs_path *path;
1019 struct btrfs_file_extent_item *fi;
1020 struct extent_buffer *leaf;
1021 int ret;
1022
1023 path = btrfs_alloc_path();
1024 if (!path)
1025 return -ENOMEM;
1026
1027 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1028 ret = btrfs_lookup_file_extent(NULL, root, path,
1029 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1030 if (ret < 0)
1031 goto out;
1032 if (ret > 0) {
1033 ret = -ENOENT;
1034 goto out;
1035 }
1036
1037 leaf = path->nodes[0];
1038 fi = btrfs_item_ptr(leaf, path->slots[0],
1039 struct btrfs_file_extent_item);
1040
1041 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1042 btrfs_file_extent_compression(leaf, fi) ||
1043 btrfs_file_extent_encryption(leaf, fi) ||
1044 btrfs_file_extent_other_encoding(leaf, fi));
1045
1046 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1047 ret = -EINVAL;
1048 goto out;
1049 }
1050
1051 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1052 ret = 0;
1053out:
1054 btrfs_free_path(path);
1055 return ret;
1056}
1057
1058/*
1059 * update file extent items in the tree leaf to point to
1060 * the new locations.
1061 */
1062static noinline_for_stack
1063int replace_file_extents(struct btrfs_trans_handle *trans,
1064 struct reloc_control *rc,
1065 struct btrfs_root *root,
1066 struct extent_buffer *leaf)
1067{
1068 struct btrfs_fs_info *fs_info = root->fs_info;
1069 struct btrfs_key key;
1070 struct btrfs_file_extent_item *fi;
1071 struct inode *inode = NULL;
1072 u64 parent;
1073 u64 bytenr;
1074 u64 new_bytenr = 0;
1075 u64 num_bytes;
1076 u64 end;
1077 u32 nritems;
1078 u32 i;
1079 int ret = 0;
1080 int first = 1;
1081 int dirty = 0;
1082
1083 if (rc->stage != UPDATE_DATA_PTRS)
1084 return 0;
1085
1086 /* reloc trees always use full backref */
1087 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1088 parent = leaf->start;
1089 else
1090 parent = 0;
1091
1092 nritems = btrfs_header_nritems(leaf);
1093 for (i = 0; i < nritems; i++) {
1094 struct btrfs_ref ref = { 0 };
1095
1096 cond_resched();
1097 btrfs_item_key_to_cpu(leaf, &key, i);
1098 if (key.type != BTRFS_EXTENT_DATA_KEY)
1099 continue;
1100 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1101 if (btrfs_file_extent_type(leaf, fi) ==
1102 BTRFS_FILE_EXTENT_INLINE)
1103 continue;
1104 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1105 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1106 if (bytenr == 0)
1107 continue;
1108 if (!in_range(bytenr, rc->block_group->start,
1109 rc->block_group->length))
1110 continue;
1111
1112 /*
1113 * if we are modifying block in fs tree, wait for read_folio
1114 * to complete and drop the extent cache
1115 */
1116 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1117 if (first) {
1118 inode = find_next_inode(root, key.objectid);
1119 first = 0;
1120 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1121 btrfs_add_delayed_iput(BTRFS_I(inode));
1122 inode = find_next_inode(root, key.objectid);
1123 }
1124 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1125 struct extent_state *cached_state = NULL;
1126
1127 end = key.offset +
1128 btrfs_file_extent_num_bytes(leaf, fi);
1129 WARN_ON(!IS_ALIGNED(key.offset,
1130 fs_info->sectorsize));
1131 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1132 end--;
1133 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1134 key.offset, end,
1135 &cached_state);
1136 if (!ret)
1137 continue;
1138
1139 btrfs_drop_extent_map_range(BTRFS_I(inode),
1140 key.offset, end, true);
1141 unlock_extent(&BTRFS_I(inode)->io_tree,
1142 key.offset, end, &cached_state);
1143 }
1144 }
1145
1146 ret = get_new_location(rc->data_inode, &new_bytenr,
1147 bytenr, num_bytes);
1148 if (ret) {
1149 /*
1150 * Don't have to abort since we've not changed anything
1151 * in the file extent yet.
1152 */
1153 break;
1154 }
1155
1156 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1157 dirty = 1;
1158
1159 key.offset -= btrfs_file_extent_offset(leaf, fi);
1160 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1161 num_bytes, parent);
1162 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1163 key.objectid, key.offset,
1164 root->root_key.objectid, false);
1165 ret = btrfs_inc_extent_ref(trans, &ref);
1166 if (ret) {
1167 btrfs_abort_transaction(trans, ret);
1168 break;
1169 }
1170
1171 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1172 num_bytes, parent);
1173 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1174 key.objectid, key.offset,
1175 root->root_key.objectid, false);
1176 ret = btrfs_free_extent(trans, &ref);
1177 if (ret) {
1178 btrfs_abort_transaction(trans, ret);
1179 break;
1180 }
1181 }
1182 if (dirty)
1183 btrfs_mark_buffer_dirty(leaf);
1184 if (inode)
1185 btrfs_add_delayed_iput(BTRFS_I(inode));
1186 return ret;
1187}
1188
1189static noinline_for_stack
1190int memcmp_node_keys(struct extent_buffer *eb, int slot,
1191 struct btrfs_path *path, int level)
1192{
1193 struct btrfs_disk_key key1;
1194 struct btrfs_disk_key key2;
1195 btrfs_node_key(eb, &key1, slot);
1196 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1197 return memcmp(&key1, &key2, sizeof(key1));
1198}
1199
1200/*
1201 * try to replace tree blocks in fs tree with the new blocks
1202 * in reloc tree. tree blocks haven't been modified since the
1203 * reloc tree was create can be replaced.
1204 *
1205 * if a block was replaced, level of the block + 1 is returned.
1206 * if no block got replaced, 0 is returned. if there are other
1207 * errors, a negative error number is returned.
1208 */
1209static noinline_for_stack
1210int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1211 struct btrfs_root *dest, struct btrfs_root *src,
1212 struct btrfs_path *path, struct btrfs_key *next_key,
1213 int lowest_level, int max_level)
1214{
1215 struct btrfs_fs_info *fs_info = dest->fs_info;
1216 struct extent_buffer *eb;
1217 struct extent_buffer *parent;
1218 struct btrfs_ref ref = { 0 };
1219 struct btrfs_key key;
1220 u64 old_bytenr;
1221 u64 new_bytenr;
1222 u64 old_ptr_gen;
1223 u64 new_ptr_gen;
1224 u64 last_snapshot;
1225 u32 blocksize;
1226 int cow = 0;
1227 int level;
1228 int ret;
1229 int slot;
1230
1231 ASSERT(src->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1232 ASSERT(dest->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1233
1234 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1235again:
1236 slot = path->slots[lowest_level];
1237 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1238
1239 eb = btrfs_lock_root_node(dest);
1240 level = btrfs_header_level(eb);
1241
1242 if (level < lowest_level) {
1243 btrfs_tree_unlock(eb);
1244 free_extent_buffer(eb);
1245 return 0;
1246 }
1247
1248 if (cow) {
1249 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb,
1250 BTRFS_NESTING_COW);
1251 if (ret) {
1252 btrfs_tree_unlock(eb);
1253 free_extent_buffer(eb);
1254 return ret;
1255 }
1256 }
1257
1258 if (next_key) {
1259 next_key->objectid = (u64)-1;
1260 next_key->type = (u8)-1;
1261 next_key->offset = (u64)-1;
1262 }
1263
1264 parent = eb;
1265 while (1) {
1266 level = btrfs_header_level(parent);
1267 ASSERT(level >= lowest_level);
1268
1269 ret = btrfs_bin_search(parent, &key, &slot);
1270 if (ret < 0)
1271 break;
1272 if (ret && slot > 0)
1273 slot--;
1274
1275 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1276 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1277
1278 old_bytenr = btrfs_node_blockptr(parent, slot);
1279 blocksize = fs_info->nodesize;
1280 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1281
1282 if (level <= max_level) {
1283 eb = path->nodes[level];
1284 new_bytenr = btrfs_node_blockptr(eb,
1285 path->slots[level]);
1286 new_ptr_gen = btrfs_node_ptr_generation(eb,
1287 path->slots[level]);
1288 } else {
1289 new_bytenr = 0;
1290 new_ptr_gen = 0;
1291 }
1292
1293 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1294 ret = level;
1295 break;
1296 }
1297
1298 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1299 memcmp_node_keys(parent, slot, path, level)) {
1300 if (level <= lowest_level) {
1301 ret = 0;
1302 break;
1303 }
1304
1305 eb = btrfs_read_node_slot(parent, slot);
1306 if (IS_ERR(eb)) {
1307 ret = PTR_ERR(eb);
1308 break;
1309 }
1310 btrfs_tree_lock(eb);
1311 if (cow) {
1312 ret = btrfs_cow_block(trans, dest, eb, parent,
1313 slot, &eb,
1314 BTRFS_NESTING_COW);
1315 if (ret) {
1316 btrfs_tree_unlock(eb);
1317 free_extent_buffer(eb);
1318 break;
1319 }
1320 }
1321
1322 btrfs_tree_unlock(parent);
1323 free_extent_buffer(parent);
1324
1325 parent = eb;
1326 continue;
1327 }
1328
1329 if (!cow) {
1330 btrfs_tree_unlock(parent);
1331 free_extent_buffer(parent);
1332 cow = 1;
1333 goto again;
1334 }
1335
1336 btrfs_node_key_to_cpu(path->nodes[level], &key,
1337 path->slots[level]);
1338 btrfs_release_path(path);
1339
1340 path->lowest_level = level;
1341 set_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state);
1342 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1343 clear_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state);
1344 path->lowest_level = 0;
1345 if (ret) {
1346 if (ret > 0)
1347 ret = -ENOENT;
1348 break;
1349 }
1350
1351 /*
1352 * Info qgroup to trace both subtrees.
1353 *
1354 * We must trace both trees.
1355 * 1) Tree reloc subtree
1356 * If not traced, we will leak data numbers
1357 * 2) Fs subtree
1358 * If not traced, we will double count old data
1359 *
1360 * We don't scan the subtree right now, but only record
1361 * the swapped tree blocks.
1362 * The real subtree rescan is delayed until we have new
1363 * CoW on the subtree root node before transaction commit.
1364 */
1365 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1366 rc->block_group, parent, slot,
1367 path->nodes[level], path->slots[level],
1368 last_snapshot);
1369 if (ret < 0)
1370 break;
1371 /*
1372 * swap blocks in fs tree and reloc tree.
1373 */
1374 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1375 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1376 btrfs_mark_buffer_dirty(parent);
1377
1378 btrfs_set_node_blockptr(path->nodes[level],
1379 path->slots[level], old_bytenr);
1380 btrfs_set_node_ptr_generation(path->nodes[level],
1381 path->slots[level], old_ptr_gen);
1382 btrfs_mark_buffer_dirty(path->nodes[level]);
1383
1384 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
1385 blocksize, path->nodes[level]->start);
1386 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid,
1387 0, true);
1388 ret = btrfs_inc_extent_ref(trans, &ref);
1389 if (ret) {
1390 btrfs_abort_transaction(trans, ret);
1391 break;
1392 }
1393 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1394 blocksize, 0);
1395 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid, 0,
1396 true);
1397 ret = btrfs_inc_extent_ref(trans, &ref);
1398 if (ret) {
1399 btrfs_abort_transaction(trans, ret);
1400 break;
1401 }
1402
1403 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
1404 blocksize, path->nodes[level]->start);
1405 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid,
1406 0, true);
1407 ret = btrfs_free_extent(trans, &ref);
1408 if (ret) {
1409 btrfs_abort_transaction(trans, ret);
1410 break;
1411 }
1412
1413 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1414 blocksize, 0);
1415 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid,
1416 0, true);
1417 ret = btrfs_free_extent(trans, &ref);
1418 if (ret) {
1419 btrfs_abort_transaction(trans, ret);
1420 break;
1421 }
1422
1423 btrfs_unlock_up_safe(path, 0);
1424
1425 ret = level;
1426 break;
1427 }
1428 btrfs_tree_unlock(parent);
1429 free_extent_buffer(parent);
1430 return ret;
1431}
1432
1433/*
1434 * helper to find next relocated block in reloc tree
1435 */
1436static noinline_for_stack
1437int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1438 int *level)
1439{
1440 struct extent_buffer *eb;
1441 int i;
1442 u64 last_snapshot;
1443 u32 nritems;
1444
1445 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1446
1447 for (i = 0; i < *level; i++) {
1448 free_extent_buffer(path->nodes[i]);
1449 path->nodes[i] = NULL;
1450 }
1451
1452 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1453 eb = path->nodes[i];
1454 nritems = btrfs_header_nritems(eb);
1455 while (path->slots[i] + 1 < nritems) {
1456 path->slots[i]++;
1457 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1458 last_snapshot)
1459 continue;
1460
1461 *level = i;
1462 return 0;
1463 }
1464 free_extent_buffer(path->nodes[i]);
1465 path->nodes[i] = NULL;
1466 }
1467 return 1;
1468}
1469
1470/*
1471 * walk down reloc tree to find relocated block of lowest level
1472 */
1473static noinline_for_stack
1474int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1475 int *level)
1476{
1477 struct extent_buffer *eb = NULL;
1478 int i;
1479 u64 ptr_gen = 0;
1480 u64 last_snapshot;
1481 u32 nritems;
1482
1483 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1484
1485 for (i = *level; i > 0; i--) {
1486 eb = path->nodes[i];
1487 nritems = btrfs_header_nritems(eb);
1488 while (path->slots[i] < nritems) {
1489 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1490 if (ptr_gen > last_snapshot)
1491 break;
1492 path->slots[i]++;
1493 }
1494 if (path->slots[i] >= nritems) {
1495 if (i == *level)
1496 break;
1497 *level = i + 1;
1498 return 0;
1499 }
1500 if (i == 1) {
1501 *level = i;
1502 return 0;
1503 }
1504
1505 eb = btrfs_read_node_slot(eb, path->slots[i]);
1506 if (IS_ERR(eb))
1507 return PTR_ERR(eb);
1508 BUG_ON(btrfs_header_level(eb) != i - 1);
1509 path->nodes[i - 1] = eb;
1510 path->slots[i - 1] = 0;
1511 }
1512 return 1;
1513}
1514
1515/*
1516 * invalidate extent cache for file extents whose key in range of
1517 * [min_key, max_key)
1518 */
1519static int invalidate_extent_cache(struct btrfs_root *root,
1520 struct btrfs_key *min_key,
1521 struct btrfs_key *max_key)
1522{
1523 struct btrfs_fs_info *fs_info = root->fs_info;
1524 struct inode *inode = NULL;
1525 u64 objectid;
1526 u64 start, end;
1527 u64 ino;
1528
1529 objectid = min_key->objectid;
1530 while (1) {
1531 struct extent_state *cached_state = NULL;
1532
1533 cond_resched();
1534 iput(inode);
1535
1536 if (objectid > max_key->objectid)
1537 break;
1538
1539 inode = find_next_inode(root, objectid);
1540 if (!inode)
1541 break;
1542 ino = btrfs_ino(BTRFS_I(inode));
1543
1544 if (ino > max_key->objectid) {
1545 iput(inode);
1546 break;
1547 }
1548
1549 objectid = ino + 1;
1550 if (!S_ISREG(inode->i_mode))
1551 continue;
1552
1553 if (unlikely(min_key->objectid == ino)) {
1554 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1555 continue;
1556 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1557 start = 0;
1558 else {
1559 start = min_key->offset;
1560 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
1561 }
1562 } else {
1563 start = 0;
1564 }
1565
1566 if (unlikely(max_key->objectid == ino)) {
1567 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1568 continue;
1569 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1570 end = (u64)-1;
1571 } else {
1572 if (max_key->offset == 0)
1573 continue;
1574 end = max_key->offset;
1575 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1576 end--;
1577 }
1578 } else {
1579 end = (u64)-1;
1580 }
1581
1582 /* the lock_extent waits for read_folio to complete */
1583 lock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
1584 btrfs_drop_extent_map_range(BTRFS_I(inode), start, end, true);
1585 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
1586 }
1587 return 0;
1588}
1589
1590static int find_next_key(struct btrfs_path *path, int level,
1591 struct btrfs_key *key)
1592
1593{
1594 while (level < BTRFS_MAX_LEVEL) {
1595 if (!path->nodes[level])
1596 break;
1597 if (path->slots[level] + 1 <
1598 btrfs_header_nritems(path->nodes[level])) {
1599 btrfs_node_key_to_cpu(path->nodes[level], key,
1600 path->slots[level] + 1);
1601 return 0;
1602 }
1603 level++;
1604 }
1605 return 1;
1606}
1607
1608/*
1609 * Insert current subvolume into reloc_control::dirty_subvol_roots
1610 */
1611static int insert_dirty_subvol(struct btrfs_trans_handle *trans,
1612 struct reloc_control *rc,
1613 struct btrfs_root *root)
1614{
1615 struct btrfs_root *reloc_root = root->reloc_root;
1616 struct btrfs_root_item *reloc_root_item;
1617 int ret;
1618
1619 /* @root must be a subvolume tree root with a valid reloc tree */
1620 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1621 ASSERT(reloc_root);
1622
1623 reloc_root_item = &reloc_root->root_item;
1624 memset(&reloc_root_item->drop_progress, 0,
1625 sizeof(reloc_root_item->drop_progress));
1626 btrfs_set_root_drop_level(reloc_root_item, 0);
1627 btrfs_set_root_refs(reloc_root_item, 0);
1628 ret = btrfs_update_reloc_root(trans, root);
1629 if (ret)
1630 return ret;
1631
1632 if (list_empty(&root->reloc_dirty_list)) {
1633 btrfs_grab_root(root);
1634 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
1635 }
1636
1637 return 0;
1638}
1639
1640static int clean_dirty_subvols(struct reloc_control *rc)
1641{
1642 struct btrfs_root *root;
1643 struct btrfs_root *next;
1644 int ret = 0;
1645 int ret2;
1646
1647 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
1648 reloc_dirty_list) {
1649 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1650 /* Merged subvolume, cleanup its reloc root */
1651 struct btrfs_root *reloc_root = root->reloc_root;
1652
1653 list_del_init(&root->reloc_dirty_list);
1654 root->reloc_root = NULL;
1655 /*
1656 * Need barrier to ensure clear_bit() only happens after
1657 * root->reloc_root = NULL. Pairs with have_reloc_root.
1658 */
1659 smp_wmb();
1660 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
1661 if (reloc_root) {
1662 /*
1663 * btrfs_drop_snapshot drops our ref we hold for
1664 * ->reloc_root. If it fails however we must
1665 * drop the ref ourselves.
1666 */
1667 ret2 = btrfs_drop_snapshot(reloc_root, 0, 1);
1668 if (ret2 < 0) {
1669 btrfs_put_root(reloc_root);
1670 if (!ret)
1671 ret = ret2;
1672 }
1673 }
1674 btrfs_put_root(root);
1675 } else {
1676 /* Orphan reloc tree, just clean it up */
1677 ret2 = btrfs_drop_snapshot(root, 0, 1);
1678 if (ret2 < 0) {
1679 btrfs_put_root(root);
1680 if (!ret)
1681 ret = ret2;
1682 }
1683 }
1684 }
1685 return ret;
1686}
1687
1688/*
1689 * merge the relocated tree blocks in reloc tree with corresponding
1690 * fs tree.
1691 */
1692static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1693 struct btrfs_root *root)
1694{
1695 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
1696 struct btrfs_key key;
1697 struct btrfs_key next_key;
1698 struct btrfs_trans_handle *trans = NULL;
1699 struct btrfs_root *reloc_root;
1700 struct btrfs_root_item *root_item;
1701 struct btrfs_path *path;
1702 struct extent_buffer *leaf;
1703 int reserve_level;
1704 int level;
1705 int max_level;
1706 int replaced = 0;
1707 int ret = 0;
1708 u32 min_reserved;
1709
1710 path = btrfs_alloc_path();
1711 if (!path)
1712 return -ENOMEM;
1713 path->reada = READA_FORWARD;
1714
1715 reloc_root = root->reloc_root;
1716 root_item = &reloc_root->root_item;
1717
1718 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
1719 level = btrfs_root_level(root_item);
1720 atomic_inc(&reloc_root->node->refs);
1721 path->nodes[level] = reloc_root->node;
1722 path->slots[level] = 0;
1723 } else {
1724 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
1725
1726 level = btrfs_root_drop_level(root_item);
1727 BUG_ON(level == 0);
1728 path->lowest_level = level;
1729 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
1730 path->lowest_level = 0;
1731 if (ret < 0) {
1732 btrfs_free_path(path);
1733 return ret;
1734 }
1735
1736 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
1737 path->slots[level]);
1738 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
1739
1740 btrfs_unlock_up_safe(path, 0);
1741 }
1742
1743 /*
1744 * In merge_reloc_root(), we modify the upper level pointer to swap the
1745 * tree blocks between reloc tree and subvolume tree. Thus for tree
1746 * block COW, we COW at most from level 1 to root level for each tree.
1747 *
1748 * Thus the needed metadata size is at most root_level * nodesize,
1749 * and * 2 since we have two trees to COW.
1750 */
1751 reserve_level = max_t(int, 1, btrfs_root_level(root_item));
1752 min_reserved = fs_info->nodesize * reserve_level * 2;
1753 memset(&next_key, 0, sizeof(next_key));
1754
1755 while (1) {
1756 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv,
1757 min_reserved,
1758 BTRFS_RESERVE_FLUSH_LIMIT);
1759 if (ret)
1760 goto out;
1761 trans = btrfs_start_transaction(root, 0);
1762 if (IS_ERR(trans)) {
1763 ret = PTR_ERR(trans);
1764 trans = NULL;
1765 goto out;
1766 }
1767
1768 /*
1769 * At this point we no longer have a reloc_control, so we can't
1770 * depend on btrfs_init_reloc_root to update our last_trans.
1771 *
1772 * But that's ok, we started the trans handle on our
1773 * corresponding fs_root, which means it's been added to the
1774 * dirty list. At commit time we'll still call
1775 * btrfs_update_reloc_root() and update our root item
1776 * appropriately.
1777 */
1778 reloc_root->last_trans = trans->transid;
1779 trans->block_rsv = rc->block_rsv;
1780
1781 replaced = 0;
1782 max_level = level;
1783
1784 ret = walk_down_reloc_tree(reloc_root, path, &level);
1785 if (ret < 0)
1786 goto out;
1787 if (ret > 0)
1788 break;
1789
1790 if (!find_next_key(path, level, &key) &&
1791 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
1792 ret = 0;
1793 } else {
1794 ret = replace_path(trans, rc, root, reloc_root, path,
1795 &next_key, level, max_level);
1796 }
1797 if (ret < 0)
1798 goto out;
1799 if (ret > 0) {
1800 level = ret;
1801 btrfs_node_key_to_cpu(path->nodes[level], &key,
1802 path->slots[level]);
1803 replaced = 1;
1804 }
1805
1806 ret = walk_up_reloc_tree(reloc_root, path, &level);
1807 if (ret > 0)
1808 break;
1809
1810 BUG_ON(level == 0);
1811 /*
1812 * save the merging progress in the drop_progress.
1813 * this is OK since root refs == 1 in this case.
1814 */
1815 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
1816 path->slots[level]);
1817 btrfs_set_root_drop_level(root_item, level);
1818
1819 btrfs_end_transaction_throttle(trans);
1820 trans = NULL;
1821
1822 btrfs_btree_balance_dirty(fs_info);
1823
1824 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1825 invalidate_extent_cache(root, &key, &next_key);
1826 }
1827
1828 /*
1829 * handle the case only one block in the fs tree need to be
1830 * relocated and the block is tree root.
1831 */
1832 leaf = btrfs_lock_root_node(root);
1833 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf,
1834 BTRFS_NESTING_COW);
1835 btrfs_tree_unlock(leaf);
1836 free_extent_buffer(leaf);
1837out:
1838 btrfs_free_path(path);
1839
1840 if (ret == 0) {
1841 ret = insert_dirty_subvol(trans, rc, root);
1842 if (ret)
1843 btrfs_abort_transaction(trans, ret);
1844 }
1845
1846 if (trans)
1847 btrfs_end_transaction_throttle(trans);
1848
1849 btrfs_btree_balance_dirty(fs_info);
1850
1851 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1852 invalidate_extent_cache(root, &key, &next_key);
1853
1854 return ret;
1855}
1856
1857static noinline_for_stack
1858int prepare_to_merge(struct reloc_control *rc, int err)
1859{
1860 struct btrfs_root *root = rc->extent_root;
1861 struct btrfs_fs_info *fs_info = root->fs_info;
1862 struct btrfs_root *reloc_root;
1863 struct btrfs_trans_handle *trans;
1864 LIST_HEAD(reloc_roots);
1865 u64 num_bytes = 0;
1866 int ret;
1867
1868 mutex_lock(&fs_info->reloc_mutex);
1869 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
1870 rc->merging_rsv_size += rc->nodes_relocated * 2;
1871 mutex_unlock(&fs_info->reloc_mutex);
1872
1873again:
1874 if (!err) {
1875 num_bytes = rc->merging_rsv_size;
1876 ret = btrfs_block_rsv_add(fs_info, rc->block_rsv, num_bytes,
1877 BTRFS_RESERVE_FLUSH_ALL);
1878 if (ret)
1879 err = ret;
1880 }
1881
1882 trans = btrfs_join_transaction(rc->extent_root);
1883 if (IS_ERR(trans)) {
1884 if (!err)
1885 btrfs_block_rsv_release(fs_info, rc->block_rsv,
1886 num_bytes, NULL);
1887 return PTR_ERR(trans);
1888 }
1889
1890 if (!err) {
1891 if (num_bytes != rc->merging_rsv_size) {
1892 btrfs_end_transaction(trans);
1893 btrfs_block_rsv_release(fs_info, rc->block_rsv,
1894 num_bytes, NULL);
1895 goto again;
1896 }
1897 }
1898
1899 rc->merge_reloc_tree = 1;
1900
1901 while (!list_empty(&rc->reloc_roots)) {
1902 reloc_root = list_entry(rc->reloc_roots.next,
1903 struct btrfs_root, root_list);
1904 list_del_init(&reloc_root->root_list);
1905
1906 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
1907 false);
1908 if (IS_ERR(root)) {
1909 /*
1910 * Even if we have an error we need this reloc root
1911 * back on our list so we can clean up properly.
1912 */
1913 list_add(&reloc_root->root_list, &reloc_roots);
1914 btrfs_abort_transaction(trans, (int)PTR_ERR(root));
1915 if (!err)
1916 err = PTR_ERR(root);
1917 break;
1918 }
1919 ASSERT(root->reloc_root == reloc_root);
1920
1921 /*
1922 * set reference count to 1, so btrfs_recover_relocation
1923 * knows it should resumes merging
1924 */
1925 if (!err)
1926 btrfs_set_root_refs(&reloc_root->root_item, 1);
1927 ret = btrfs_update_reloc_root(trans, root);
1928
1929 /*
1930 * Even if we have an error we need this reloc root back on our
1931 * list so we can clean up properly.
1932 */
1933 list_add(&reloc_root->root_list, &reloc_roots);
1934 btrfs_put_root(root);
1935
1936 if (ret) {
1937 btrfs_abort_transaction(trans, ret);
1938 if (!err)
1939 err = ret;
1940 break;
1941 }
1942 }
1943
1944 list_splice(&reloc_roots, &rc->reloc_roots);
1945
1946 if (!err)
1947 err = btrfs_commit_transaction(trans);
1948 else
1949 btrfs_end_transaction(trans);
1950 return err;
1951}
1952
1953static noinline_for_stack
1954void free_reloc_roots(struct list_head *list)
1955{
1956 struct btrfs_root *reloc_root, *tmp;
1957
1958 list_for_each_entry_safe(reloc_root, tmp, list, root_list)
1959 __del_reloc_root(reloc_root);
1960}
1961
1962static noinline_for_stack
1963void merge_reloc_roots(struct reloc_control *rc)
1964{
1965 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
1966 struct btrfs_root *root;
1967 struct btrfs_root *reloc_root;
1968 LIST_HEAD(reloc_roots);
1969 int found = 0;
1970 int ret = 0;
1971again:
1972 root = rc->extent_root;
1973
1974 /*
1975 * this serializes us with btrfs_record_root_in_transaction,
1976 * we have to make sure nobody is in the middle of
1977 * adding their roots to the list while we are
1978 * doing this splice
1979 */
1980 mutex_lock(&fs_info->reloc_mutex);
1981 list_splice_init(&rc->reloc_roots, &reloc_roots);
1982 mutex_unlock(&fs_info->reloc_mutex);
1983
1984 while (!list_empty(&reloc_roots)) {
1985 found = 1;
1986 reloc_root = list_entry(reloc_roots.next,
1987 struct btrfs_root, root_list);
1988
1989 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
1990 false);
1991 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
1992 if (IS_ERR(root)) {
1993 /*
1994 * For recovery we read the fs roots on mount,
1995 * and if we didn't find the root then we marked
1996 * the reloc root as a garbage root. For normal
1997 * relocation obviously the root should exist in
1998 * memory. However there's no reason we can't
1999 * handle the error properly here just in case.
2000 */
2001 ASSERT(0);
2002 ret = PTR_ERR(root);
2003 goto out;
2004 }
2005 if (root->reloc_root != reloc_root) {
2006 /*
2007 * This is actually impossible without something
2008 * going really wrong (like weird race condition
2009 * or cosmic rays).
2010 */
2011 ASSERT(0);
2012 ret = -EINVAL;
2013 goto out;
2014 }
2015 ret = merge_reloc_root(rc, root);
2016 btrfs_put_root(root);
2017 if (ret) {
2018 if (list_empty(&reloc_root->root_list))
2019 list_add_tail(&reloc_root->root_list,
2020 &reloc_roots);
2021 goto out;
2022 }
2023 } else {
2024 if (!IS_ERR(root)) {
2025 if (root->reloc_root == reloc_root) {
2026 root->reloc_root = NULL;
2027 btrfs_put_root(reloc_root);
2028 }
2029 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE,
2030 &root->state);
2031 btrfs_put_root(root);
2032 }
2033
2034 list_del_init(&reloc_root->root_list);
2035 /* Don't forget to queue this reloc root for cleanup */
2036 list_add_tail(&reloc_root->reloc_dirty_list,
2037 &rc->dirty_subvol_roots);
2038 }
2039 }
2040
2041 if (found) {
2042 found = 0;
2043 goto again;
2044 }
2045out:
2046 if (ret) {
2047 btrfs_handle_fs_error(fs_info, ret, NULL);
2048 free_reloc_roots(&reloc_roots);
2049
2050 /* new reloc root may be added */
2051 mutex_lock(&fs_info->reloc_mutex);
2052 list_splice_init(&rc->reloc_roots, &reloc_roots);
2053 mutex_unlock(&fs_info->reloc_mutex);
2054 free_reloc_roots(&reloc_roots);
2055 }
2056
2057 /*
2058 * We used to have
2059 *
2060 * BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2061 *
2062 * here, but it's wrong. If we fail to start the transaction in
2063 * prepare_to_merge() we will have only 0 ref reloc roots, none of which
2064 * have actually been removed from the reloc_root_tree rb tree. This is
2065 * fine because we're bailing here, and we hold a reference on the root
2066 * for the list that holds it, so these roots will be cleaned up when we
2067 * do the reloc_dirty_list afterwards. Meanwhile the root->reloc_root
2068 * will be cleaned up on unmount.
2069 *
2070 * The remaining nodes will be cleaned up by free_reloc_control.
2071 */
2072}
2073
2074static void free_block_list(struct rb_root *blocks)
2075{
2076 struct tree_block *block;
2077 struct rb_node *rb_node;
2078 while ((rb_node = rb_first(blocks))) {
2079 block = rb_entry(rb_node, struct tree_block, rb_node);
2080 rb_erase(rb_node, blocks);
2081 kfree(block);
2082 }
2083}
2084
2085static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2086 struct btrfs_root *reloc_root)
2087{
2088 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2089 struct btrfs_root *root;
2090 int ret;
2091
2092 if (reloc_root->last_trans == trans->transid)
2093 return 0;
2094
2095 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false);
2096
2097 /*
2098 * This should succeed, since we can't have a reloc root without having
2099 * already looked up the actual root and created the reloc root for this
2100 * root.
2101 *
2102 * However if there's some sort of corruption where we have a ref to a
2103 * reloc root without a corresponding root this could return ENOENT.
2104 */
2105 if (IS_ERR(root)) {
2106 ASSERT(0);
2107 return PTR_ERR(root);
2108 }
2109 if (root->reloc_root != reloc_root) {
2110 ASSERT(0);
2111 btrfs_err(fs_info,
2112 "root %llu has two reloc roots associated with it",
2113 reloc_root->root_key.offset);
2114 btrfs_put_root(root);
2115 return -EUCLEAN;
2116 }
2117 ret = btrfs_record_root_in_trans(trans, root);
2118 btrfs_put_root(root);
2119
2120 return ret;
2121}
2122
2123static noinline_for_stack
2124struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2125 struct reloc_control *rc,
2126 struct btrfs_backref_node *node,
2127 struct btrfs_backref_edge *edges[])
2128{
2129 struct btrfs_backref_node *next;
2130 struct btrfs_root *root;
2131 int index = 0;
2132 int ret;
2133
2134 next = node;
2135 while (1) {
2136 cond_resched();
2137 next = walk_up_backref(next, edges, &index);
2138 root = next->root;
2139
2140 /*
2141 * If there is no root, then our references for this block are
2142 * incomplete, as we should be able to walk all the way up to a
2143 * block that is owned by a root.
2144 *
2145 * This path is only for SHAREABLE roots, so if we come upon a
2146 * non-SHAREABLE root then we have backrefs that resolve
2147 * improperly.
2148 *
2149 * Both of these cases indicate file system corruption, or a bug
2150 * in the backref walking code.
2151 */
2152 if (!root) {
2153 ASSERT(0);
2154 btrfs_err(trans->fs_info,
2155 "bytenr %llu doesn't have a backref path ending in a root",
2156 node->bytenr);
2157 return ERR_PTR(-EUCLEAN);
2158 }
2159 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
2160 ASSERT(0);
2161 btrfs_err(trans->fs_info,
2162 "bytenr %llu has multiple refs with one ending in a non-shareable root",
2163 node->bytenr);
2164 return ERR_PTR(-EUCLEAN);
2165 }
2166
2167 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2168 ret = record_reloc_root_in_trans(trans, root);
2169 if (ret)
2170 return ERR_PTR(ret);
2171 break;
2172 }
2173
2174 ret = btrfs_record_root_in_trans(trans, root);
2175 if (ret)
2176 return ERR_PTR(ret);
2177 root = root->reloc_root;
2178
2179 /*
2180 * We could have raced with another thread which failed, so
2181 * root->reloc_root may not be set, return ENOENT in this case.
2182 */
2183 if (!root)
2184 return ERR_PTR(-ENOENT);
2185
2186 if (next->new_bytenr != root->node->start) {
2187 /*
2188 * We just created the reloc root, so we shouldn't have
2189 * ->new_bytenr set and this shouldn't be in the changed
2190 * list. If it is then we have multiple roots pointing
2191 * at the same bytenr which indicates corruption, or
2192 * we've made a mistake in the backref walking code.
2193 */
2194 ASSERT(next->new_bytenr == 0);
2195 ASSERT(list_empty(&next->list));
2196 if (next->new_bytenr || !list_empty(&next->list)) {
2197 btrfs_err(trans->fs_info,
2198 "bytenr %llu possibly has multiple roots pointing at the same bytenr %llu",
2199 node->bytenr, next->bytenr);
2200 return ERR_PTR(-EUCLEAN);
2201 }
2202
2203 next->new_bytenr = root->node->start;
2204 btrfs_put_root(next->root);
2205 next->root = btrfs_grab_root(root);
2206 ASSERT(next->root);
2207 list_add_tail(&next->list,
2208 &rc->backref_cache.changed);
2209 mark_block_processed(rc, next);
2210 break;
2211 }
2212
2213 WARN_ON(1);
2214 root = NULL;
2215 next = walk_down_backref(edges, &index);
2216 if (!next || next->level <= node->level)
2217 break;
2218 }
2219 if (!root) {
2220 /*
2221 * This can happen if there's fs corruption or if there's a bug
2222 * in the backref lookup code.
2223 */
2224 ASSERT(0);
2225 return ERR_PTR(-ENOENT);
2226 }
2227
2228 next = node;
2229 /* setup backref node path for btrfs_reloc_cow_block */
2230 while (1) {
2231 rc->backref_cache.path[next->level] = next;
2232 if (--index < 0)
2233 break;
2234 next = edges[index]->node[UPPER];
2235 }
2236 return root;
2237}
2238
2239/*
2240 * Select a tree root for relocation.
2241 *
2242 * Return NULL if the block is not shareable. We should use do_relocation() in
2243 * this case.
2244 *
2245 * Return a tree root pointer if the block is shareable.
2246 * Return -ENOENT if the block is root of reloc tree.
2247 */
2248static noinline_for_stack
2249struct btrfs_root *select_one_root(struct btrfs_backref_node *node)
2250{
2251 struct btrfs_backref_node *next;
2252 struct btrfs_root *root;
2253 struct btrfs_root *fs_root = NULL;
2254 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2255 int index = 0;
2256
2257 next = node;
2258 while (1) {
2259 cond_resched();
2260 next = walk_up_backref(next, edges, &index);
2261 root = next->root;
2262
2263 /*
2264 * This can occur if we have incomplete extent refs leading all
2265 * the way up a particular path, in this case return -EUCLEAN.
2266 */
2267 if (!root)
2268 return ERR_PTR(-EUCLEAN);
2269
2270 /* No other choice for non-shareable tree */
2271 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
2272 return root;
2273
2274 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2275 fs_root = root;
2276
2277 if (next != node)
2278 return NULL;
2279
2280 next = walk_down_backref(edges, &index);
2281 if (!next || next->level <= node->level)
2282 break;
2283 }
2284
2285 if (!fs_root)
2286 return ERR_PTR(-ENOENT);
2287 return fs_root;
2288}
2289
2290static noinline_for_stack
2291u64 calcu_metadata_size(struct reloc_control *rc,
2292 struct btrfs_backref_node *node, int reserve)
2293{
2294 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2295 struct btrfs_backref_node *next = node;
2296 struct btrfs_backref_edge *edge;
2297 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2298 u64 num_bytes = 0;
2299 int index = 0;
2300
2301 BUG_ON(reserve && node->processed);
2302
2303 while (next) {
2304 cond_resched();
2305 while (1) {
2306 if (next->processed && (reserve || next != node))
2307 break;
2308
2309 num_bytes += fs_info->nodesize;
2310
2311 if (list_empty(&next->upper))
2312 break;
2313
2314 edge = list_entry(next->upper.next,
2315 struct btrfs_backref_edge, list[LOWER]);
2316 edges[index++] = edge;
2317 next = edge->node[UPPER];
2318 }
2319 next = walk_down_backref(edges, &index);
2320 }
2321 return num_bytes;
2322}
2323
2324static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2325 struct reloc_control *rc,
2326 struct btrfs_backref_node *node)
2327{
2328 struct btrfs_root *root = rc->extent_root;
2329 struct btrfs_fs_info *fs_info = root->fs_info;
2330 u64 num_bytes;
2331 int ret;
2332 u64 tmp;
2333
2334 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2335
2336 trans->block_rsv = rc->block_rsv;
2337 rc->reserved_bytes += num_bytes;
2338
2339 /*
2340 * We are under a transaction here so we can only do limited flushing.
2341 * If we get an enospc just kick back -EAGAIN so we know to drop the
2342 * transaction and try to refill when we can flush all the things.
2343 */
2344 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv, num_bytes,
2345 BTRFS_RESERVE_FLUSH_LIMIT);
2346 if (ret) {
2347 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2348 while (tmp <= rc->reserved_bytes)
2349 tmp <<= 1;
2350 /*
2351 * only one thread can access block_rsv at this point,
2352 * so we don't need hold lock to protect block_rsv.
2353 * we expand more reservation size here to allow enough
2354 * space for relocation and we will return earlier in
2355 * enospc case.
2356 */
2357 rc->block_rsv->size = tmp + fs_info->nodesize *
2358 RELOCATION_RESERVED_NODES;
2359 return -EAGAIN;
2360 }
2361
2362 return 0;
2363}
2364
2365/*
2366 * relocate a block tree, and then update pointers in upper level
2367 * blocks that reference the block to point to the new location.
2368 *
2369 * if called by link_to_upper, the block has already been relocated.
2370 * in that case this function just updates pointers.
2371 */
2372static int do_relocation(struct btrfs_trans_handle *trans,
2373 struct reloc_control *rc,
2374 struct btrfs_backref_node *node,
2375 struct btrfs_key *key,
2376 struct btrfs_path *path, int lowest)
2377{
2378 struct btrfs_backref_node *upper;
2379 struct btrfs_backref_edge *edge;
2380 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2381 struct btrfs_root *root;
2382 struct extent_buffer *eb;
2383 u32 blocksize;
2384 u64 bytenr;
2385 int slot;
2386 int ret = 0;
2387
2388 /*
2389 * If we are lowest then this is the first time we're processing this
2390 * block, and thus shouldn't have an eb associated with it yet.
2391 */
2392 ASSERT(!lowest || !node->eb);
2393
2394 path->lowest_level = node->level + 1;
2395 rc->backref_cache.path[node->level] = node;
2396 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2397 struct btrfs_ref ref = { 0 };
2398
2399 cond_resched();
2400
2401 upper = edge->node[UPPER];
2402 root = select_reloc_root(trans, rc, upper, edges);
2403 if (IS_ERR(root)) {
2404 ret = PTR_ERR(root);
2405 goto next;
2406 }
2407
2408 if (upper->eb && !upper->locked) {
2409 if (!lowest) {
2410 ret = btrfs_bin_search(upper->eb, key, &slot);
2411 if (ret < 0)
2412 goto next;
2413 BUG_ON(ret);
2414 bytenr = btrfs_node_blockptr(upper->eb, slot);
2415 if (node->eb->start == bytenr)
2416 goto next;
2417 }
2418 btrfs_backref_drop_node_buffer(upper);
2419 }
2420
2421 if (!upper->eb) {
2422 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2423 if (ret) {
2424 if (ret > 0)
2425 ret = -ENOENT;
2426
2427 btrfs_release_path(path);
2428 break;
2429 }
2430
2431 if (!upper->eb) {
2432 upper->eb = path->nodes[upper->level];
2433 path->nodes[upper->level] = NULL;
2434 } else {
2435 BUG_ON(upper->eb != path->nodes[upper->level]);
2436 }
2437
2438 upper->locked = 1;
2439 path->locks[upper->level] = 0;
2440
2441 slot = path->slots[upper->level];
2442 btrfs_release_path(path);
2443 } else {
2444 ret = btrfs_bin_search(upper->eb, key, &slot);
2445 if (ret < 0)
2446 goto next;
2447 BUG_ON(ret);
2448 }
2449
2450 bytenr = btrfs_node_blockptr(upper->eb, slot);
2451 if (lowest) {
2452 if (bytenr != node->bytenr) {
2453 btrfs_err(root->fs_info,
2454 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2455 bytenr, node->bytenr, slot,
2456 upper->eb->start);
2457 ret = -EIO;
2458 goto next;
2459 }
2460 } else {
2461 if (node->eb->start == bytenr)
2462 goto next;
2463 }
2464
2465 blocksize = root->fs_info->nodesize;
2466 eb = btrfs_read_node_slot(upper->eb, slot);
2467 if (IS_ERR(eb)) {
2468 ret = PTR_ERR(eb);
2469 goto next;
2470 }
2471 btrfs_tree_lock(eb);
2472
2473 if (!node->eb) {
2474 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2475 slot, &eb, BTRFS_NESTING_COW);
2476 btrfs_tree_unlock(eb);
2477 free_extent_buffer(eb);
2478 if (ret < 0)
2479 goto next;
2480 /*
2481 * We've just COWed this block, it should have updated
2482 * the correct backref node entry.
2483 */
2484 ASSERT(node->eb == eb);
2485 } else {
2486 btrfs_set_node_blockptr(upper->eb, slot,
2487 node->eb->start);
2488 btrfs_set_node_ptr_generation(upper->eb, slot,
2489 trans->transid);
2490 btrfs_mark_buffer_dirty(upper->eb);
2491
2492 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2493 node->eb->start, blocksize,
2494 upper->eb->start);
2495 btrfs_init_tree_ref(&ref, node->level,
2496 btrfs_header_owner(upper->eb),
2497 root->root_key.objectid, false);
2498 ret = btrfs_inc_extent_ref(trans, &ref);
2499 if (!ret)
2500 ret = btrfs_drop_subtree(trans, root, eb,
2501 upper->eb);
2502 if (ret)
2503 btrfs_abort_transaction(trans, ret);
2504 }
2505next:
2506 if (!upper->pending)
2507 btrfs_backref_drop_node_buffer(upper);
2508 else
2509 btrfs_backref_unlock_node_buffer(upper);
2510 if (ret)
2511 break;
2512 }
2513
2514 if (!ret && node->pending) {
2515 btrfs_backref_drop_node_buffer(node);
2516 list_move_tail(&node->list, &rc->backref_cache.changed);
2517 node->pending = 0;
2518 }
2519
2520 path->lowest_level = 0;
2521
2522 /*
2523 * We should have allocated all of our space in the block rsv and thus
2524 * shouldn't ENOSPC.
2525 */
2526 ASSERT(ret != -ENOSPC);
2527 return ret;
2528}
2529
2530static int link_to_upper(struct btrfs_trans_handle *trans,
2531 struct reloc_control *rc,
2532 struct btrfs_backref_node *node,
2533 struct btrfs_path *path)
2534{
2535 struct btrfs_key key;
2536
2537 btrfs_node_key_to_cpu(node->eb, &key, 0);
2538 return do_relocation(trans, rc, node, &key, path, 0);
2539}
2540
2541static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2542 struct reloc_control *rc,
2543 struct btrfs_path *path, int err)
2544{
2545 LIST_HEAD(list);
2546 struct btrfs_backref_cache *cache = &rc->backref_cache;
2547 struct btrfs_backref_node *node;
2548 int level;
2549 int ret;
2550
2551 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2552 while (!list_empty(&cache->pending[level])) {
2553 node = list_entry(cache->pending[level].next,
2554 struct btrfs_backref_node, list);
2555 list_move_tail(&node->list, &list);
2556 BUG_ON(!node->pending);
2557
2558 if (!err) {
2559 ret = link_to_upper(trans, rc, node, path);
2560 if (ret < 0)
2561 err = ret;
2562 }
2563 }
2564 list_splice_init(&list, &cache->pending[level]);
2565 }
2566 return err;
2567}
2568
2569/*
2570 * mark a block and all blocks directly/indirectly reference the block
2571 * as processed.
2572 */
2573static void update_processed_blocks(struct reloc_control *rc,
2574 struct btrfs_backref_node *node)
2575{
2576 struct btrfs_backref_node *next = node;
2577 struct btrfs_backref_edge *edge;
2578 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2579 int index = 0;
2580
2581 while (next) {
2582 cond_resched();
2583 while (1) {
2584 if (next->processed)
2585 break;
2586
2587 mark_block_processed(rc, next);
2588
2589 if (list_empty(&next->upper))
2590 break;
2591
2592 edge = list_entry(next->upper.next,
2593 struct btrfs_backref_edge, list[LOWER]);
2594 edges[index++] = edge;
2595 next = edge->node[UPPER];
2596 }
2597 next = walk_down_backref(edges, &index);
2598 }
2599}
2600
2601static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2602{
2603 u32 blocksize = rc->extent_root->fs_info->nodesize;
2604
2605 if (test_range_bit(&rc->processed_blocks, bytenr,
2606 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2607 return 1;
2608 return 0;
2609}
2610
2611static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2612 struct tree_block *block)
2613{
2614 struct btrfs_tree_parent_check check = {
2615 .level = block->level,
2616 .owner_root = block->owner,
2617 .transid = block->key.offset
2618 };
2619 struct extent_buffer *eb;
2620
2621 eb = read_tree_block(fs_info, block->bytenr, &check);
2622 if (IS_ERR(eb))
2623 return PTR_ERR(eb);
2624 if (!extent_buffer_uptodate(eb)) {
2625 free_extent_buffer(eb);
2626 return -EIO;
2627 }
2628 if (block->level == 0)
2629 btrfs_item_key_to_cpu(eb, &block->key, 0);
2630 else
2631 btrfs_node_key_to_cpu(eb, &block->key, 0);
2632 free_extent_buffer(eb);
2633 block->key_ready = 1;
2634 return 0;
2635}
2636
2637/*
2638 * helper function to relocate a tree block
2639 */
2640static int relocate_tree_block(struct btrfs_trans_handle *trans,
2641 struct reloc_control *rc,
2642 struct btrfs_backref_node *node,
2643 struct btrfs_key *key,
2644 struct btrfs_path *path)
2645{
2646 struct btrfs_root *root;
2647 int ret = 0;
2648
2649 if (!node)
2650 return 0;
2651
2652 /*
2653 * If we fail here we want to drop our backref_node because we are going
2654 * to start over and regenerate the tree for it.
2655 */
2656 ret = reserve_metadata_space(trans, rc, node);
2657 if (ret)
2658 goto out;
2659
2660 BUG_ON(node->processed);
2661 root = select_one_root(node);
2662 if (IS_ERR(root)) {
2663 ret = PTR_ERR(root);
2664
2665 /* See explanation in select_one_root for the -EUCLEAN case. */
2666 ASSERT(ret == -ENOENT);
2667 if (ret == -ENOENT) {
2668 ret = 0;
2669 update_processed_blocks(rc, node);
2670 }
2671 goto out;
2672 }
2673
2674 if (root) {
2675 if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
2676 /*
2677 * This block was the root block of a root, and this is
2678 * the first time we're processing the block and thus it
2679 * should not have had the ->new_bytenr modified and
2680 * should have not been included on the changed list.
2681 *
2682 * However in the case of corruption we could have
2683 * multiple refs pointing to the same block improperly,
2684 * and thus we would trip over these checks. ASSERT()
2685 * for the developer case, because it could indicate a
2686 * bug in the backref code, however error out for a
2687 * normal user in the case of corruption.
2688 */
2689 ASSERT(node->new_bytenr == 0);
2690 ASSERT(list_empty(&node->list));
2691 if (node->new_bytenr || !list_empty(&node->list)) {
2692 btrfs_err(root->fs_info,
2693 "bytenr %llu has improper references to it",
2694 node->bytenr);
2695 ret = -EUCLEAN;
2696 goto out;
2697 }
2698 ret = btrfs_record_root_in_trans(trans, root);
2699 if (ret)
2700 goto out;
2701 /*
2702 * Another thread could have failed, need to check if we
2703 * have reloc_root actually set.
2704 */
2705 if (!root->reloc_root) {
2706 ret = -ENOENT;
2707 goto out;
2708 }
2709 root = root->reloc_root;
2710 node->new_bytenr = root->node->start;
2711 btrfs_put_root(node->root);
2712 node->root = btrfs_grab_root(root);
2713 ASSERT(node->root);
2714 list_add_tail(&node->list, &rc->backref_cache.changed);
2715 } else {
2716 path->lowest_level = node->level;
2717 if (root == root->fs_info->chunk_root)
2718 btrfs_reserve_chunk_metadata(trans, false);
2719 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2720 btrfs_release_path(path);
2721 if (root == root->fs_info->chunk_root)
2722 btrfs_trans_release_chunk_metadata(trans);
2723 if (ret > 0)
2724 ret = 0;
2725 }
2726 if (!ret)
2727 update_processed_blocks(rc, node);
2728 } else {
2729 ret = do_relocation(trans, rc, node, key, path, 1);
2730 }
2731out:
2732 if (ret || node->level == 0 || node->cowonly)
2733 btrfs_backref_cleanup_node(&rc->backref_cache, node);
2734 return ret;
2735}
2736
2737/*
2738 * relocate a list of blocks
2739 */
2740static noinline_for_stack
2741int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2742 struct reloc_control *rc, struct rb_root *blocks)
2743{
2744 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2745 struct btrfs_backref_node *node;
2746 struct btrfs_path *path;
2747 struct tree_block *block;
2748 struct tree_block *next;
2749 int ret;
2750 int err = 0;
2751
2752 path = btrfs_alloc_path();
2753 if (!path) {
2754 err = -ENOMEM;
2755 goto out_free_blocks;
2756 }
2757
2758 /* Kick in readahead for tree blocks with missing keys */
2759 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2760 if (!block->key_ready)
2761 btrfs_readahead_tree_block(fs_info, block->bytenr,
2762 block->owner, 0,
2763 block->level);
2764 }
2765
2766 /* Get first keys */
2767 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2768 if (!block->key_ready) {
2769 err = get_tree_block_key(fs_info, block);
2770 if (err)
2771 goto out_free_path;
2772 }
2773 }
2774
2775 /* Do tree relocation */
2776 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2777 node = build_backref_tree(rc, &block->key,
2778 block->level, block->bytenr);
2779 if (IS_ERR(node)) {
2780 err = PTR_ERR(node);
2781 goto out;
2782 }
2783
2784 ret = relocate_tree_block(trans, rc, node, &block->key,
2785 path);
2786 if (ret < 0) {
2787 err = ret;
2788 break;
2789 }
2790 }
2791out:
2792 err = finish_pending_nodes(trans, rc, path, err);
2793
2794out_free_path:
2795 btrfs_free_path(path);
2796out_free_blocks:
2797 free_block_list(blocks);
2798 return err;
2799}
2800
2801static noinline_for_stack int prealloc_file_extent_cluster(
2802 struct btrfs_inode *inode,
2803 struct file_extent_cluster *cluster)
2804{
2805 u64 alloc_hint = 0;
2806 u64 start;
2807 u64 end;
2808 u64 offset = inode->index_cnt;
2809 u64 num_bytes;
2810 int nr;
2811 int ret = 0;
2812 u64 i_size = i_size_read(&inode->vfs_inode);
2813 u64 prealloc_start = cluster->start - offset;
2814 u64 prealloc_end = cluster->end - offset;
2815 u64 cur_offset = prealloc_start;
2816
2817 /*
2818 * For subpage case, previous i_size may not be aligned to PAGE_SIZE.
2819 * This means the range [i_size, PAGE_END + 1) is filled with zeros by
2820 * btrfs_do_readpage() call of previously relocated file cluster.
2821 *
2822 * If the current cluster starts in the above range, btrfs_do_readpage()
2823 * will skip the read, and relocate_one_page() will later writeback
2824 * the padding zeros as new data, causing data corruption.
2825 *
2826 * Here we have to manually invalidate the range (i_size, PAGE_END + 1).
2827 */
2828 if (!IS_ALIGNED(i_size, PAGE_SIZE)) {
2829 struct address_space *mapping = inode->vfs_inode.i_mapping;
2830 struct btrfs_fs_info *fs_info = inode->root->fs_info;
2831 const u32 sectorsize = fs_info->sectorsize;
2832 struct page *page;
2833
2834 ASSERT(sectorsize < PAGE_SIZE);
2835 ASSERT(IS_ALIGNED(i_size, sectorsize));
2836
2837 /*
2838 * Subpage can't handle page with DIRTY but without UPTODATE
2839 * bit as it can lead to the following deadlock:
2840 *
2841 * btrfs_read_folio()
2842 * | Page already *locked*
2843 * |- btrfs_lock_and_flush_ordered_range()
2844 * |- btrfs_start_ordered_extent()
2845 * |- extent_write_cache_pages()
2846 * |- lock_page()
2847 * We try to lock the page we already hold.
2848 *
2849 * Here we just writeback the whole data reloc inode, so that
2850 * we will be ensured to have no dirty range in the page, and
2851 * are safe to clear the uptodate bits.
2852 *
2853 * This shouldn't cause too much overhead, as we need to write
2854 * the data back anyway.
2855 */
2856 ret = filemap_write_and_wait(mapping);
2857 if (ret < 0)
2858 return ret;
2859
2860 clear_extent_bits(&inode->io_tree, i_size,
2861 round_up(i_size, PAGE_SIZE) - 1,
2862 EXTENT_UPTODATE);
2863 page = find_lock_page(mapping, i_size >> PAGE_SHIFT);
2864 /*
2865 * If page is freed we don't need to do anything then, as we
2866 * will re-read the whole page anyway.
2867 */
2868 if (page) {
2869 btrfs_subpage_clear_uptodate(fs_info, page, i_size,
2870 round_up(i_size, PAGE_SIZE) - i_size);
2871 unlock_page(page);
2872 put_page(page);
2873 }
2874 }
2875
2876 BUG_ON(cluster->start != cluster->boundary[0]);
2877 ret = btrfs_alloc_data_chunk_ondemand(inode,
2878 prealloc_end + 1 - prealloc_start);
2879 if (ret)
2880 return ret;
2881
2882 btrfs_inode_lock(inode, 0);
2883 for (nr = 0; nr < cluster->nr; nr++) {
2884 struct extent_state *cached_state = NULL;
2885
2886 start = cluster->boundary[nr] - offset;
2887 if (nr + 1 < cluster->nr)
2888 end = cluster->boundary[nr + 1] - 1 - offset;
2889 else
2890 end = cluster->end - offset;
2891
2892 lock_extent(&inode->io_tree, start, end, &cached_state);
2893 num_bytes = end + 1 - start;
2894 ret = btrfs_prealloc_file_range(&inode->vfs_inode, 0, start,
2895 num_bytes, num_bytes,
2896 end + 1, &alloc_hint);
2897 cur_offset = end + 1;
2898 unlock_extent(&inode->io_tree, start, end, &cached_state);
2899 if (ret)
2900 break;
2901 }
2902 btrfs_inode_unlock(inode, 0);
2903
2904 if (cur_offset < prealloc_end)
2905 btrfs_free_reserved_data_space_noquota(inode->root->fs_info,
2906 prealloc_end + 1 - cur_offset);
2907 return ret;
2908}
2909
2910static noinline_for_stack int setup_relocation_extent_mapping(struct inode *inode,
2911 u64 start, u64 end, u64 block_start)
2912{
2913 struct extent_map *em;
2914 struct extent_state *cached_state = NULL;
2915 int ret = 0;
2916
2917 em = alloc_extent_map();
2918 if (!em)
2919 return -ENOMEM;
2920
2921 em->start = start;
2922 em->len = end + 1 - start;
2923 em->block_len = em->len;
2924 em->block_start = block_start;
2925 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2926
2927 lock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
2928 ret = btrfs_replace_extent_map_range(BTRFS_I(inode), em, false);
2929 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
2930 free_extent_map(em);
2931
2932 return ret;
2933}
2934
2935/*
2936 * Allow error injection to test balance/relocation cancellation
2937 */
2938noinline int btrfs_should_cancel_balance(struct btrfs_fs_info *fs_info)
2939{
2940 return atomic_read(&fs_info->balance_cancel_req) ||
2941 atomic_read(&fs_info->reloc_cancel_req) ||
2942 fatal_signal_pending(current);
2943}
2944ALLOW_ERROR_INJECTION(btrfs_should_cancel_balance, TRUE);
2945
2946static u64 get_cluster_boundary_end(struct file_extent_cluster *cluster,
2947 int cluster_nr)
2948{
2949 /* Last extent, use cluster end directly */
2950 if (cluster_nr >= cluster->nr - 1)
2951 return cluster->end;
2952
2953 /* Use next boundary start*/
2954 return cluster->boundary[cluster_nr + 1] - 1;
2955}
2956
2957static int relocate_one_page(struct inode *inode, struct file_ra_state *ra,
2958 struct file_extent_cluster *cluster,
2959 int *cluster_nr, unsigned long page_index)
2960{
2961 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2962 u64 offset = BTRFS_I(inode)->index_cnt;
2963 const unsigned long last_index = (cluster->end - offset) >> PAGE_SHIFT;
2964 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
2965 struct page *page;
2966 u64 page_start;
2967 u64 page_end;
2968 u64 cur;
2969 int ret;
2970
2971 ASSERT(page_index <= last_index);
2972 page = find_lock_page(inode->i_mapping, page_index);
2973 if (!page) {
2974 page_cache_sync_readahead(inode->i_mapping, ra, NULL,
2975 page_index, last_index + 1 - page_index);
2976 page = find_or_create_page(inode->i_mapping, page_index, mask);
2977 if (!page)
2978 return -ENOMEM;
2979 }
2980 ret = set_page_extent_mapped(page);
2981 if (ret < 0)
2982 goto release_page;
2983
2984 if (PageReadahead(page))
2985 page_cache_async_readahead(inode->i_mapping, ra, NULL,
2986 page_folio(page), page_index,
2987 last_index + 1 - page_index);
2988
2989 if (!PageUptodate(page)) {
2990 btrfs_read_folio(NULL, page_folio(page));
2991 lock_page(page);
2992 if (!PageUptodate(page)) {
2993 ret = -EIO;
2994 goto release_page;
2995 }
2996 }
2997
2998 page_start = page_offset(page);
2999 page_end = page_start + PAGE_SIZE - 1;
3000
3001 /*
3002 * Start from the cluster, as for subpage case, the cluster can start
3003 * inside the page.
3004 */
3005 cur = max(page_start, cluster->boundary[*cluster_nr] - offset);
3006 while (cur <= page_end) {
3007 struct extent_state *cached_state = NULL;
3008 u64 extent_start = cluster->boundary[*cluster_nr] - offset;
3009 u64 extent_end = get_cluster_boundary_end(cluster,
3010 *cluster_nr) - offset;
3011 u64 clamped_start = max(page_start, extent_start);
3012 u64 clamped_end = min(page_end, extent_end);
3013 u32 clamped_len = clamped_end + 1 - clamped_start;
3014
3015 /* Reserve metadata for this range */
3016 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3017 clamped_len, clamped_len,
3018 false);
3019 if (ret)
3020 goto release_page;
3021
3022 /* Mark the range delalloc and dirty for later writeback */
3023 lock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end,
3024 &cached_state);
3025 ret = btrfs_set_extent_delalloc(BTRFS_I(inode), clamped_start,
3026 clamped_end, 0, &cached_state);
3027 if (ret) {
3028 clear_extent_bit(&BTRFS_I(inode)->io_tree,
3029 clamped_start, clamped_end,
3030 EXTENT_LOCKED | EXTENT_BOUNDARY,
3031 &cached_state);
3032 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3033 clamped_len, true);
3034 btrfs_delalloc_release_extents(BTRFS_I(inode),
3035 clamped_len);
3036 goto release_page;
3037 }
3038 btrfs_page_set_dirty(fs_info, page, clamped_start, clamped_len);
3039
3040 /*
3041 * Set the boundary if it's inside the page.
3042 * Data relocation requires the destination extents to have the
3043 * same size as the source.
3044 * EXTENT_BOUNDARY bit prevents current extent from being merged
3045 * with previous extent.
3046 */
3047 if (in_range(cluster->boundary[*cluster_nr] - offset,
3048 page_start, PAGE_SIZE)) {
3049 u64 boundary_start = cluster->boundary[*cluster_nr] -
3050 offset;
3051 u64 boundary_end = boundary_start +
3052 fs_info->sectorsize - 1;
3053
3054 set_extent_bits(&BTRFS_I(inode)->io_tree,
3055 boundary_start, boundary_end,
3056 EXTENT_BOUNDARY);
3057 }
3058 unlock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end,
3059 &cached_state);
3060 btrfs_delalloc_release_extents(BTRFS_I(inode), clamped_len);
3061 cur += clamped_len;
3062
3063 /* Crossed extent end, go to next extent */
3064 if (cur >= extent_end) {
3065 (*cluster_nr)++;
3066 /* Just finished the last extent of the cluster, exit. */
3067 if (*cluster_nr >= cluster->nr)
3068 break;
3069 }
3070 }
3071 unlock_page(page);
3072 put_page(page);
3073
3074 balance_dirty_pages_ratelimited(inode->i_mapping);
3075 btrfs_throttle(fs_info);
3076 if (btrfs_should_cancel_balance(fs_info))
3077 ret = -ECANCELED;
3078 return ret;
3079
3080release_page:
3081 unlock_page(page);
3082 put_page(page);
3083 return ret;
3084}
3085
3086static int relocate_file_extent_cluster(struct inode *inode,
3087 struct file_extent_cluster *cluster)
3088{
3089 u64 offset = BTRFS_I(inode)->index_cnt;
3090 unsigned long index;
3091 unsigned long last_index;
3092 struct file_ra_state *ra;
3093 int cluster_nr = 0;
3094 int ret = 0;
3095
3096 if (!cluster->nr)
3097 return 0;
3098
3099 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3100 if (!ra)
3101 return -ENOMEM;
3102
3103 ret = prealloc_file_extent_cluster(BTRFS_I(inode), cluster);
3104 if (ret)
3105 goto out;
3106
3107 file_ra_state_init(ra, inode->i_mapping);
3108
3109 ret = setup_relocation_extent_mapping(inode, cluster->start - offset,
3110 cluster->end - offset, cluster->start);
3111 if (ret)
3112 goto out;
3113
3114 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3115 for (index = (cluster->start - offset) >> PAGE_SHIFT;
3116 index <= last_index && !ret; index++)
3117 ret = relocate_one_page(inode, ra, cluster, &cluster_nr, index);
3118 if (ret == 0)
3119 WARN_ON(cluster_nr != cluster->nr);
3120out:
3121 kfree(ra);
3122 return ret;
3123}
3124
3125static noinline_for_stack
3126int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3127 struct file_extent_cluster *cluster)
3128{
3129 int ret;
3130
3131 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3132 ret = relocate_file_extent_cluster(inode, cluster);
3133 if (ret)
3134 return ret;
3135 cluster->nr = 0;
3136 }
3137
3138 if (!cluster->nr)
3139 cluster->start = extent_key->objectid;
3140 else
3141 BUG_ON(cluster->nr >= MAX_EXTENTS);
3142 cluster->end = extent_key->objectid + extent_key->offset - 1;
3143 cluster->boundary[cluster->nr] = extent_key->objectid;
3144 cluster->nr++;
3145
3146 if (cluster->nr >= MAX_EXTENTS) {
3147 ret = relocate_file_extent_cluster(inode, cluster);
3148 if (ret)
3149 return ret;
3150 cluster->nr = 0;
3151 }
3152 return 0;
3153}
3154
3155/*
3156 * helper to add a tree block to the list.
3157 * the major work is getting the generation and level of the block
3158 */
3159static int add_tree_block(struct reloc_control *rc,
3160 struct btrfs_key *extent_key,
3161 struct btrfs_path *path,
3162 struct rb_root *blocks)
3163{
3164 struct extent_buffer *eb;
3165 struct btrfs_extent_item *ei;
3166 struct btrfs_tree_block_info *bi;
3167 struct tree_block *block;
3168 struct rb_node *rb_node;
3169 u32 item_size;
3170 int level = -1;
3171 u64 generation;
3172 u64 owner = 0;
3173
3174 eb = path->nodes[0];
3175 item_size = btrfs_item_size(eb, path->slots[0]);
3176
3177 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3178 item_size >= sizeof(*ei) + sizeof(*bi)) {
3179 unsigned long ptr = 0, end;
3180
3181 ei = btrfs_item_ptr(eb, path->slots[0],
3182 struct btrfs_extent_item);
3183 end = (unsigned long)ei + item_size;
3184 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3185 bi = (struct btrfs_tree_block_info *)(ei + 1);
3186 level = btrfs_tree_block_level(eb, bi);
3187 ptr = (unsigned long)(bi + 1);
3188 } else {
3189 level = (int)extent_key->offset;
3190 ptr = (unsigned long)(ei + 1);
3191 }
3192 generation = btrfs_extent_generation(eb, ei);
3193
3194 /*
3195 * We're reading random blocks without knowing their owner ahead
3196 * of time. This is ok most of the time, as all reloc roots and
3197 * fs roots have the same lock type. However normal trees do
3198 * not, and the only way to know ahead of time is to read the
3199 * inline ref offset. We know it's an fs root if
3200 *
3201 * 1. There's more than one ref.
3202 * 2. There's a SHARED_DATA_REF_KEY set.
3203 * 3. FULL_BACKREF is set on the flags.
3204 *
3205 * Otherwise it's safe to assume that the ref offset == the
3206 * owner of this block, so we can use that when calling
3207 * read_tree_block.
3208 */
3209 if (btrfs_extent_refs(eb, ei) == 1 &&
3210 !(btrfs_extent_flags(eb, ei) &
3211 BTRFS_BLOCK_FLAG_FULL_BACKREF) &&
3212 ptr < end) {
3213 struct btrfs_extent_inline_ref *iref;
3214 int type;
3215
3216 iref = (struct btrfs_extent_inline_ref *)ptr;
3217 type = btrfs_get_extent_inline_ref_type(eb, iref,
3218 BTRFS_REF_TYPE_BLOCK);
3219 if (type == BTRFS_REF_TYPE_INVALID)
3220 return -EINVAL;
3221 if (type == BTRFS_TREE_BLOCK_REF_KEY)
3222 owner = btrfs_extent_inline_ref_offset(eb, iref);
3223 }
3224 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3225 btrfs_print_v0_err(eb->fs_info);
3226 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3227 return -EINVAL;
3228 } else {
3229 BUG();
3230 }
3231
3232 btrfs_release_path(path);
3233
3234 BUG_ON(level == -1);
3235
3236 block = kmalloc(sizeof(*block), GFP_NOFS);
3237 if (!block)
3238 return -ENOMEM;
3239
3240 block->bytenr = extent_key->objectid;
3241 block->key.objectid = rc->extent_root->fs_info->nodesize;
3242 block->key.offset = generation;
3243 block->level = level;
3244 block->key_ready = 0;
3245 block->owner = owner;
3246
3247 rb_node = rb_simple_insert(blocks, block->bytenr, &block->rb_node);
3248 if (rb_node)
3249 btrfs_backref_panic(rc->extent_root->fs_info, block->bytenr,
3250 -EEXIST);
3251
3252 return 0;
3253}
3254
3255/*
3256 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3257 */
3258static int __add_tree_block(struct reloc_control *rc,
3259 u64 bytenr, u32 blocksize,
3260 struct rb_root *blocks)
3261{
3262 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3263 struct btrfs_path *path;
3264 struct btrfs_key key;
3265 int ret;
3266 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3267
3268 if (tree_block_processed(bytenr, rc))
3269 return 0;
3270
3271 if (rb_simple_search(blocks, bytenr))
3272 return 0;
3273
3274 path = btrfs_alloc_path();
3275 if (!path)
3276 return -ENOMEM;
3277again:
3278 key.objectid = bytenr;
3279 if (skinny) {
3280 key.type = BTRFS_METADATA_ITEM_KEY;
3281 key.offset = (u64)-1;
3282 } else {
3283 key.type = BTRFS_EXTENT_ITEM_KEY;
3284 key.offset = blocksize;
3285 }
3286
3287 path->search_commit_root = 1;
3288 path->skip_locking = 1;
3289 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3290 if (ret < 0)
3291 goto out;
3292
3293 if (ret > 0 && skinny) {
3294 if (path->slots[0]) {
3295 path->slots[0]--;
3296 btrfs_item_key_to_cpu(path->nodes[0], &key,
3297 path->slots[0]);
3298 if (key.objectid == bytenr &&
3299 (key.type == BTRFS_METADATA_ITEM_KEY ||
3300 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3301 key.offset == blocksize)))
3302 ret = 0;
3303 }
3304
3305 if (ret) {
3306 skinny = false;
3307 btrfs_release_path(path);
3308 goto again;
3309 }
3310 }
3311 if (ret) {
3312 ASSERT(ret == 1);
3313 btrfs_print_leaf(path->nodes[0]);
3314 btrfs_err(fs_info,
3315 "tree block extent item (%llu) is not found in extent tree",
3316 bytenr);
3317 WARN_ON(1);
3318 ret = -EINVAL;
3319 goto out;
3320 }
3321
3322 ret = add_tree_block(rc, &key, path, blocks);
3323out:
3324 btrfs_free_path(path);
3325 return ret;
3326}
3327
3328static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3329 struct btrfs_block_group *block_group,
3330 struct inode *inode,
3331 u64 ino)
3332{
3333 struct btrfs_root *root = fs_info->tree_root;
3334 struct btrfs_trans_handle *trans;
3335 int ret = 0;
3336
3337 if (inode)
3338 goto truncate;
3339
3340 inode = btrfs_iget(fs_info->sb, ino, root);
3341 if (IS_ERR(inode))
3342 return -ENOENT;
3343
3344truncate:
3345 ret = btrfs_check_trunc_cache_free_space(fs_info,
3346 &fs_info->global_block_rsv);
3347 if (ret)
3348 goto out;
3349
3350 trans = btrfs_join_transaction(root);
3351 if (IS_ERR(trans)) {
3352 ret = PTR_ERR(trans);
3353 goto out;
3354 }
3355
3356 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3357
3358 btrfs_end_transaction(trans);
3359 btrfs_btree_balance_dirty(fs_info);
3360out:
3361 iput(inode);
3362 return ret;
3363}
3364
3365/*
3366 * Locate the free space cache EXTENT_DATA in root tree leaf and delete the
3367 * cache inode, to avoid free space cache data extent blocking data relocation.
3368 */
3369static int delete_v1_space_cache(struct extent_buffer *leaf,
3370 struct btrfs_block_group *block_group,
3371 u64 data_bytenr)
3372{
3373 u64 space_cache_ino;
3374 struct btrfs_file_extent_item *ei;
3375 struct btrfs_key key;
3376 bool found = false;
3377 int i;
3378 int ret;
3379
3380 if (btrfs_header_owner(leaf) != BTRFS_ROOT_TREE_OBJECTID)
3381 return 0;
3382
3383 for (i = 0; i < btrfs_header_nritems(leaf); i++) {
3384 u8 type;
3385
3386 btrfs_item_key_to_cpu(leaf, &key, i);
3387 if (key.type != BTRFS_EXTENT_DATA_KEY)
3388 continue;
3389 ei = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
3390 type = btrfs_file_extent_type(leaf, ei);
3391
3392 if ((type == BTRFS_FILE_EXTENT_REG ||
3393 type == BTRFS_FILE_EXTENT_PREALLOC) &&
3394 btrfs_file_extent_disk_bytenr(leaf, ei) == data_bytenr) {
3395 found = true;
3396 space_cache_ino = key.objectid;
3397 break;
3398 }
3399 }
3400 if (!found)
3401 return -ENOENT;
3402 ret = delete_block_group_cache(leaf->fs_info, block_group, NULL,
3403 space_cache_ino);
3404 return ret;
3405}
3406
3407/*
3408 * helper to find all tree blocks that reference a given data extent
3409 */
3410static noinline_for_stack
3411int add_data_references(struct reloc_control *rc,
3412 struct btrfs_key *extent_key,
3413 struct btrfs_path *path,
3414 struct rb_root *blocks)
3415{
3416 struct btrfs_backref_walk_ctx ctx = { 0 };
3417 struct ulist_iterator leaf_uiter;
3418 struct ulist_node *ref_node = NULL;
3419 const u32 blocksize = rc->extent_root->fs_info->nodesize;
3420 int ret = 0;
3421
3422 btrfs_release_path(path);
3423
3424 ctx.bytenr = extent_key->objectid;
3425 ctx.ignore_extent_item_pos = true;
3426 ctx.fs_info = rc->extent_root->fs_info;
3427
3428 ret = btrfs_find_all_leafs(&ctx);
3429 if (ret < 0)
3430 return ret;
3431
3432 ULIST_ITER_INIT(&leaf_uiter);
3433 while ((ref_node = ulist_next(ctx.refs, &leaf_uiter))) {
3434 struct btrfs_tree_parent_check check = { 0 };
3435 struct extent_buffer *eb;
3436
3437 eb = read_tree_block(ctx.fs_info, ref_node->val, &check);
3438 if (IS_ERR(eb)) {
3439 ret = PTR_ERR(eb);
3440 break;
3441 }
3442 ret = delete_v1_space_cache(eb, rc->block_group,
3443 extent_key->objectid);
3444 free_extent_buffer(eb);
3445 if (ret < 0)
3446 break;
3447 ret = __add_tree_block(rc, ref_node->val, blocksize, blocks);
3448 if (ret < 0)
3449 break;
3450 }
3451 if (ret < 0)
3452 free_block_list(blocks);
3453 ulist_free(ctx.refs);
3454 return ret;
3455}
3456
3457/*
3458 * helper to find next unprocessed extent
3459 */
3460static noinline_for_stack
3461int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3462 struct btrfs_key *extent_key)
3463{
3464 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3465 struct btrfs_key key;
3466 struct extent_buffer *leaf;
3467 u64 start, end, last;
3468 int ret;
3469
3470 last = rc->block_group->start + rc->block_group->length;
3471 while (1) {
3472 cond_resched();
3473 if (rc->search_start >= last) {
3474 ret = 1;
3475 break;
3476 }
3477
3478 key.objectid = rc->search_start;
3479 key.type = BTRFS_EXTENT_ITEM_KEY;
3480 key.offset = 0;
3481
3482 path->search_commit_root = 1;
3483 path->skip_locking = 1;
3484 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3485 0, 0);
3486 if (ret < 0)
3487 break;
3488next:
3489 leaf = path->nodes[0];
3490 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3491 ret = btrfs_next_leaf(rc->extent_root, path);
3492 if (ret != 0)
3493 break;
3494 leaf = path->nodes[0];
3495 }
3496
3497 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3498 if (key.objectid >= last) {
3499 ret = 1;
3500 break;
3501 }
3502
3503 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3504 key.type != BTRFS_METADATA_ITEM_KEY) {
3505 path->slots[0]++;
3506 goto next;
3507 }
3508
3509 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3510 key.objectid + key.offset <= rc->search_start) {
3511 path->slots[0]++;
3512 goto next;
3513 }
3514
3515 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3516 key.objectid + fs_info->nodesize <=
3517 rc->search_start) {
3518 path->slots[0]++;
3519 goto next;
3520 }
3521
3522 ret = find_first_extent_bit(&rc->processed_blocks,
3523 key.objectid, &start, &end,
3524 EXTENT_DIRTY, NULL);
3525
3526 if (ret == 0 && start <= key.objectid) {
3527 btrfs_release_path(path);
3528 rc->search_start = end + 1;
3529 } else {
3530 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3531 rc->search_start = key.objectid + key.offset;
3532 else
3533 rc->search_start = key.objectid +
3534 fs_info->nodesize;
3535 memcpy(extent_key, &key, sizeof(key));
3536 return 0;
3537 }
3538 }
3539 btrfs_release_path(path);
3540 return ret;
3541}
3542
3543static void set_reloc_control(struct reloc_control *rc)
3544{
3545 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3546
3547 mutex_lock(&fs_info->reloc_mutex);
3548 fs_info->reloc_ctl = rc;
3549 mutex_unlock(&fs_info->reloc_mutex);
3550}
3551
3552static void unset_reloc_control(struct reloc_control *rc)
3553{
3554 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3555
3556 mutex_lock(&fs_info->reloc_mutex);
3557 fs_info->reloc_ctl = NULL;
3558 mutex_unlock(&fs_info->reloc_mutex);
3559}
3560
3561static noinline_for_stack
3562int prepare_to_relocate(struct reloc_control *rc)
3563{
3564 struct btrfs_trans_handle *trans;
3565 int ret;
3566
3567 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3568 BTRFS_BLOCK_RSV_TEMP);
3569 if (!rc->block_rsv)
3570 return -ENOMEM;
3571
3572 memset(&rc->cluster, 0, sizeof(rc->cluster));
3573 rc->search_start = rc->block_group->start;
3574 rc->extents_found = 0;
3575 rc->nodes_relocated = 0;
3576 rc->merging_rsv_size = 0;
3577 rc->reserved_bytes = 0;
3578 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3579 RELOCATION_RESERVED_NODES;
3580 ret = btrfs_block_rsv_refill(rc->extent_root->fs_info,
3581 rc->block_rsv, rc->block_rsv->size,
3582 BTRFS_RESERVE_FLUSH_ALL);
3583 if (ret)
3584 return ret;
3585
3586 rc->create_reloc_tree = 1;
3587 set_reloc_control(rc);
3588
3589 trans = btrfs_join_transaction(rc->extent_root);
3590 if (IS_ERR(trans)) {
3591 unset_reloc_control(rc);
3592 /*
3593 * extent tree is not a ref_cow tree and has no reloc_root to
3594 * cleanup. And callers are responsible to free the above
3595 * block rsv.
3596 */
3597 return PTR_ERR(trans);
3598 }
3599
3600 ret = btrfs_commit_transaction(trans);
3601 if (ret)
3602 unset_reloc_control(rc);
3603
3604 return ret;
3605}
3606
3607static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3608{
3609 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3610 struct rb_root blocks = RB_ROOT;
3611 struct btrfs_key key;
3612 struct btrfs_trans_handle *trans = NULL;
3613 struct btrfs_path *path;
3614 struct btrfs_extent_item *ei;
3615 u64 flags;
3616 int ret;
3617 int err = 0;
3618 int progress = 0;
3619
3620 path = btrfs_alloc_path();
3621 if (!path)
3622 return -ENOMEM;
3623 path->reada = READA_FORWARD;
3624
3625 ret = prepare_to_relocate(rc);
3626 if (ret) {
3627 err = ret;
3628 goto out_free;
3629 }
3630
3631 while (1) {
3632 rc->reserved_bytes = 0;
3633 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv,
3634 rc->block_rsv->size,
3635 BTRFS_RESERVE_FLUSH_ALL);
3636 if (ret) {
3637 err = ret;
3638 break;
3639 }
3640 progress++;
3641 trans = btrfs_start_transaction(rc->extent_root, 0);
3642 if (IS_ERR(trans)) {
3643 err = PTR_ERR(trans);
3644 trans = NULL;
3645 break;
3646 }
3647restart:
3648 if (update_backref_cache(trans, &rc->backref_cache)) {
3649 btrfs_end_transaction(trans);
3650 trans = NULL;
3651 continue;
3652 }
3653
3654 ret = find_next_extent(rc, path, &key);
3655 if (ret < 0)
3656 err = ret;
3657 if (ret != 0)
3658 break;
3659
3660 rc->extents_found++;
3661
3662 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3663 struct btrfs_extent_item);
3664 flags = btrfs_extent_flags(path->nodes[0], ei);
3665
3666 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3667 ret = add_tree_block(rc, &key, path, &blocks);
3668 } else if (rc->stage == UPDATE_DATA_PTRS &&
3669 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3670 ret = add_data_references(rc, &key, path, &blocks);
3671 } else {
3672 btrfs_release_path(path);
3673 ret = 0;
3674 }
3675 if (ret < 0) {
3676 err = ret;
3677 break;
3678 }
3679
3680 if (!RB_EMPTY_ROOT(&blocks)) {
3681 ret = relocate_tree_blocks(trans, rc, &blocks);
3682 if (ret < 0) {
3683 if (ret != -EAGAIN) {
3684 err = ret;
3685 break;
3686 }
3687 rc->extents_found--;
3688 rc->search_start = key.objectid;
3689 }
3690 }
3691
3692 btrfs_end_transaction_throttle(trans);
3693 btrfs_btree_balance_dirty(fs_info);
3694 trans = NULL;
3695
3696 if (rc->stage == MOVE_DATA_EXTENTS &&
3697 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3698 rc->found_file_extent = 1;
3699 ret = relocate_data_extent(rc->data_inode,
3700 &key, &rc->cluster);
3701 if (ret < 0) {
3702 err = ret;
3703 break;
3704 }
3705 }
3706 if (btrfs_should_cancel_balance(fs_info)) {
3707 err = -ECANCELED;
3708 break;
3709 }
3710 }
3711 if (trans && progress && err == -ENOSPC) {
3712 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
3713 if (ret == 1) {
3714 err = 0;
3715 progress = 0;
3716 goto restart;
3717 }
3718 }
3719
3720 btrfs_release_path(path);
3721 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
3722
3723 if (trans) {
3724 btrfs_end_transaction_throttle(trans);
3725 btrfs_btree_balance_dirty(fs_info);
3726 }
3727
3728 if (!err) {
3729 ret = relocate_file_extent_cluster(rc->data_inode,
3730 &rc->cluster);
3731 if (ret < 0)
3732 err = ret;
3733 }
3734
3735 rc->create_reloc_tree = 0;
3736 set_reloc_control(rc);
3737
3738 btrfs_backref_release_cache(&rc->backref_cache);
3739 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
3740
3741 /*
3742 * Even in the case when the relocation is cancelled, we should all go
3743 * through prepare_to_merge() and merge_reloc_roots().
3744 *
3745 * For error (including cancelled balance), prepare_to_merge() will
3746 * mark all reloc trees orphan, then queue them for cleanup in
3747 * merge_reloc_roots()
3748 */
3749 err = prepare_to_merge(rc, err);
3750
3751 merge_reloc_roots(rc);
3752
3753 rc->merge_reloc_tree = 0;
3754 unset_reloc_control(rc);
3755 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
3756
3757 /* get rid of pinned extents */
3758 trans = btrfs_join_transaction(rc->extent_root);
3759 if (IS_ERR(trans)) {
3760 err = PTR_ERR(trans);
3761 goto out_free;
3762 }
3763 ret = btrfs_commit_transaction(trans);
3764 if (ret && !err)
3765 err = ret;
3766out_free:
3767 ret = clean_dirty_subvols(rc);
3768 if (ret < 0 && !err)
3769 err = ret;
3770 btrfs_free_block_rsv(fs_info, rc->block_rsv);
3771 btrfs_free_path(path);
3772 return err;
3773}
3774
3775static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3776 struct btrfs_root *root, u64 objectid)
3777{
3778 struct btrfs_path *path;
3779 struct btrfs_inode_item *item;
3780 struct extent_buffer *leaf;
3781 int ret;
3782
3783 path = btrfs_alloc_path();
3784 if (!path)
3785 return -ENOMEM;
3786
3787 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3788 if (ret)
3789 goto out;
3790
3791 leaf = path->nodes[0];
3792 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3793 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
3794 btrfs_set_inode_generation(leaf, item, 1);
3795 btrfs_set_inode_size(leaf, item, 0);
3796 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3797 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3798 BTRFS_INODE_PREALLOC);
3799 btrfs_mark_buffer_dirty(leaf);
3800out:
3801 btrfs_free_path(path);
3802 return ret;
3803}
3804
3805static void delete_orphan_inode(struct btrfs_trans_handle *trans,
3806 struct btrfs_root *root, u64 objectid)
3807{
3808 struct btrfs_path *path;
3809 struct btrfs_key key;
3810 int ret = 0;
3811
3812 path = btrfs_alloc_path();
3813 if (!path) {
3814 ret = -ENOMEM;
3815 goto out;
3816 }
3817
3818 key.objectid = objectid;
3819 key.type = BTRFS_INODE_ITEM_KEY;
3820 key.offset = 0;
3821 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3822 if (ret) {
3823 if (ret > 0)
3824 ret = -ENOENT;
3825 goto out;
3826 }
3827 ret = btrfs_del_item(trans, root, path);
3828out:
3829 if (ret)
3830 btrfs_abort_transaction(trans, ret);
3831 btrfs_free_path(path);
3832}
3833
3834/*
3835 * helper to create inode for data relocation.
3836 * the inode is in data relocation tree and its link count is 0
3837 */
3838static noinline_for_stack
3839struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3840 struct btrfs_block_group *group)
3841{
3842 struct inode *inode = NULL;
3843 struct btrfs_trans_handle *trans;
3844 struct btrfs_root *root;
3845 u64 objectid;
3846 int err = 0;
3847
3848 root = btrfs_grab_root(fs_info->data_reloc_root);
3849 trans = btrfs_start_transaction(root, 6);
3850 if (IS_ERR(trans)) {
3851 btrfs_put_root(root);
3852 return ERR_CAST(trans);
3853 }
3854
3855 err = btrfs_get_free_objectid(root, &objectid);
3856 if (err)
3857 goto out;
3858
3859 err = __insert_orphan_inode(trans, root, objectid);
3860 if (err)
3861 goto out;
3862
3863 inode = btrfs_iget(fs_info->sb, objectid, root);
3864 if (IS_ERR(inode)) {
3865 delete_orphan_inode(trans, root, objectid);
3866 err = PTR_ERR(inode);
3867 inode = NULL;
3868 goto out;
3869 }
3870 BTRFS_I(inode)->index_cnt = group->start;
3871
3872 err = btrfs_orphan_add(trans, BTRFS_I(inode));
3873out:
3874 btrfs_put_root(root);
3875 btrfs_end_transaction(trans);
3876 btrfs_btree_balance_dirty(fs_info);
3877 if (err) {
3878 iput(inode);
3879 inode = ERR_PTR(err);
3880 }
3881 return inode;
3882}
3883
3884/*
3885 * Mark start of chunk relocation that is cancellable. Check if the cancellation
3886 * has been requested meanwhile and don't start in that case.
3887 *
3888 * Return:
3889 * 0 success
3890 * -EINPROGRESS operation is already in progress, that's probably a bug
3891 * -ECANCELED cancellation request was set before the operation started
3892 */
3893static int reloc_chunk_start(struct btrfs_fs_info *fs_info)
3894{
3895 if (test_and_set_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) {
3896 /* This should not happen */
3897 btrfs_err(fs_info, "reloc already running, cannot start");
3898 return -EINPROGRESS;
3899 }
3900
3901 if (atomic_read(&fs_info->reloc_cancel_req) > 0) {
3902 btrfs_info(fs_info, "chunk relocation canceled on start");
3903 /*
3904 * On cancel, clear all requests but let the caller mark
3905 * the end after cleanup operations.
3906 */
3907 atomic_set(&fs_info->reloc_cancel_req, 0);
3908 return -ECANCELED;
3909 }
3910 return 0;
3911}
3912
3913/*
3914 * Mark end of chunk relocation that is cancellable and wake any waiters.
3915 */
3916static void reloc_chunk_end(struct btrfs_fs_info *fs_info)
3917{
3918 /* Requested after start, clear bit first so any waiters can continue */
3919 if (atomic_read(&fs_info->reloc_cancel_req) > 0)
3920 btrfs_info(fs_info, "chunk relocation canceled during operation");
3921 clear_and_wake_up_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags);
3922 atomic_set(&fs_info->reloc_cancel_req, 0);
3923}
3924
3925static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
3926{
3927 struct reloc_control *rc;
3928
3929 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3930 if (!rc)
3931 return NULL;
3932
3933 INIT_LIST_HEAD(&rc->reloc_roots);
3934 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
3935 btrfs_backref_init_cache(fs_info, &rc->backref_cache, 1);
3936 mapping_tree_init(&rc->reloc_root_tree);
3937 extent_io_tree_init(fs_info, &rc->processed_blocks, IO_TREE_RELOC_BLOCKS);
3938 return rc;
3939}
3940
3941static void free_reloc_control(struct reloc_control *rc)
3942{
3943 struct mapping_node *node, *tmp;
3944
3945 free_reloc_roots(&rc->reloc_roots);
3946 rbtree_postorder_for_each_entry_safe(node, tmp,
3947 &rc->reloc_root_tree.rb_root, rb_node)
3948 kfree(node);
3949
3950 kfree(rc);
3951}
3952
3953/*
3954 * Print the block group being relocated
3955 */
3956static void describe_relocation(struct btrfs_fs_info *fs_info,
3957 struct btrfs_block_group *block_group)
3958{
3959 char buf[128] = {'\0'};
3960
3961 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
3962
3963 btrfs_info(fs_info,
3964 "relocating block group %llu flags %s",
3965 block_group->start, buf);
3966}
3967
3968static const char *stage_to_string(int stage)
3969{
3970 if (stage == MOVE_DATA_EXTENTS)
3971 return "move data extents";
3972 if (stage == UPDATE_DATA_PTRS)
3973 return "update data pointers";
3974 return "unknown";
3975}
3976
3977/*
3978 * function to relocate all extents in a block group.
3979 */
3980int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
3981{
3982 struct btrfs_block_group *bg;
3983 struct btrfs_root *extent_root = btrfs_extent_root(fs_info, group_start);
3984 struct reloc_control *rc;
3985 struct inode *inode;
3986 struct btrfs_path *path;
3987 int ret;
3988 int rw = 0;
3989 int err = 0;
3990
3991 /*
3992 * This only gets set if we had a half-deleted snapshot on mount. We
3993 * cannot allow relocation to start while we're still trying to clean up
3994 * these pending deletions.
3995 */
3996 ret = wait_on_bit(&fs_info->flags, BTRFS_FS_UNFINISHED_DROPS, TASK_INTERRUPTIBLE);
3997 if (ret)
3998 return ret;
3999
4000 /* We may have been woken up by close_ctree, so bail if we're closing. */
4001 if (btrfs_fs_closing(fs_info))
4002 return -EINTR;
4003
4004 bg = btrfs_lookup_block_group(fs_info, group_start);
4005 if (!bg)
4006 return -ENOENT;
4007
4008 /*
4009 * Relocation of a data block group creates ordered extents. Without
4010 * sb_start_write(), we can freeze the filesystem while unfinished
4011 * ordered extents are left. Such ordered extents can cause a deadlock
4012 * e.g. when syncfs() is waiting for their completion but they can't
4013 * finish because they block when joining a transaction, due to the
4014 * fact that the freeze locks are being held in write mode.
4015 */
4016 if (bg->flags & BTRFS_BLOCK_GROUP_DATA)
4017 ASSERT(sb_write_started(fs_info->sb));
4018
4019 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4020 btrfs_put_block_group(bg);
4021 return -ETXTBSY;
4022 }
4023
4024 rc = alloc_reloc_control(fs_info);
4025 if (!rc) {
4026 btrfs_put_block_group(bg);
4027 return -ENOMEM;
4028 }
4029
4030 ret = reloc_chunk_start(fs_info);
4031 if (ret < 0) {
4032 err = ret;
4033 goto out_put_bg;
4034 }
4035
4036 rc->extent_root = extent_root;
4037 rc->block_group = bg;
4038
4039 ret = btrfs_inc_block_group_ro(rc->block_group, true);
4040 if (ret) {
4041 err = ret;
4042 goto out;
4043 }
4044 rw = 1;
4045
4046 path = btrfs_alloc_path();
4047 if (!path) {
4048 err = -ENOMEM;
4049 goto out;
4050 }
4051
4052 inode = lookup_free_space_inode(rc->block_group, path);
4053 btrfs_free_path(path);
4054
4055 if (!IS_ERR(inode))
4056 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4057 else
4058 ret = PTR_ERR(inode);
4059
4060 if (ret && ret != -ENOENT) {
4061 err = ret;
4062 goto out;
4063 }
4064
4065 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4066 if (IS_ERR(rc->data_inode)) {
4067 err = PTR_ERR(rc->data_inode);
4068 rc->data_inode = NULL;
4069 goto out;
4070 }
4071
4072 describe_relocation(fs_info, rc->block_group);
4073
4074 btrfs_wait_block_group_reservations(rc->block_group);
4075 btrfs_wait_nocow_writers(rc->block_group);
4076 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4077 rc->block_group->start,
4078 rc->block_group->length);
4079
4080 ret = btrfs_zone_finish(rc->block_group);
4081 WARN_ON(ret && ret != -EAGAIN);
4082
4083 while (1) {
4084 int finishes_stage;
4085
4086 mutex_lock(&fs_info->cleaner_mutex);
4087 ret = relocate_block_group(rc);
4088 mutex_unlock(&fs_info->cleaner_mutex);
4089 if (ret < 0)
4090 err = ret;
4091
4092 finishes_stage = rc->stage;
4093 /*
4094 * We may have gotten ENOSPC after we already dirtied some
4095 * extents. If writeout happens while we're relocating a
4096 * different block group we could end up hitting the
4097 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4098 * btrfs_reloc_cow_block. Make sure we write everything out
4099 * properly so we don't trip over this problem, and then break
4100 * out of the loop if we hit an error.
4101 */
4102 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4103 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4104 (u64)-1);
4105 if (ret)
4106 err = ret;
4107 invalidate_mapping_pages(rc->data_inode->i_mapping,
4108 0, -1);
4109 rc->stage = UPDATE_DATA_PTRS;
4110 }
4111
4112 if (err < 0)
4113 goto out;
4114
4115 if (rc->extents_found == 0)
4116 break;
4117
4118 btrfs_info(fs_info, "found %llu extents, stage: %s",
4119 rc->extents_found, stage_to_string(finishes_stage));
4120 }
4121
4122 WARN_ON(rc->block_group->pinned > 0);
4123 WARN_ON(rc->block_group->reserved > 0);
4124 WARN_ON(rc->block_group->used > 0);
4125out:
4126 if (err && rw)
4127 btrfs_dec_block_group_ro(rc->block_group);
4128 iput(rc->data_inode);
4129out_put_bg:
4130 btrfs_put_block_group(bg);
4131 reloc_chunk_end(fs_info);
4132 free_reloc_control(rc);
4133 return err;
4134}
4135
4136static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4137{
4138 struct btrfs_fs_info *fs_info = root->fs_info;
4139 struct btrfs_trans_handle *trans;
4140 int ret, err;
4141
4142 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4143 if (IS_ERR(trans))
4144 return PTR_ERR(trans);
4145
4146 memset(&root->root_item.drop_progress, 0,
4147 sizeof(root->root_item.drop_progress));
4148 btrfs_set_root_drop_level(&root->root_item, 0);
4149 btrfs_set_root_refs(&root->root_item, 0);
4150 ret = btrfs_update_root(trans, fs_info->tree_root,
4151 &root->root_key, &root->root_item);
4152
4153 err = btrfs_end_transaction(trans);
4154 if (err)
4155 return err;
4156 return ret;
4157}
4158
4159/*
4160 * recover relocation interrupted by system crash.
4161 *
4162 * this function resumes merging reloc trees with corresponding fs trees.
4163 * this is important for keeping the sharing of tree blocks
4164 */
4165int btrfs_recover_relocation(struct btrfs_fs_info *fs_info)
4166{
4167 LIST_HEAD(reloc_roots);
4168 struct btrfs_key key;
4169 struct btrfs_root *fs_root;
4170 struct btrfs_root *reloc_root;
4171 struct btrfs_path *path;
4172 struct extent_buffer *leaf;
4173 struct reloc_control *rc = NULL;
4174 struct btrfs_trans_handle *trans;
4175 int ret;
4176 int err = 0;
4177
4178 path = btrfs_alloc_path();
4179 if (!path)
4180 return -ENOMEM;
4181 path->reada = READA_BACK;
4182
4183 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4184 key.type = BTRFS_ROOT_ITEM_KEY;
4185 key.offset = (u64)-1;
4186
4187 while (1) {
4188 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4189 path, 0, 0);
4190 if (ret < 0) {
4191 err = ret;
4192 goto out;
4193 }
4194 if (ret > 0) {
4195 if (path->slots[0] == 0)
4196 break;
4197 path->slots[0]--;
4198 }
4199 leaf = path->nodes[0];
4200 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4201 btrfs_release_path(path);
4202
4203 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4204 key.type != BTRFS_ROOT_ITEM_KEY)
4205 break;
4206
4207 reloc_root = btrfs_read_tree_root(fs_info->tree_root, &key);
4208 if (IS_ERR(reloc_root)) {
4209 err = PTR_ERR(reloc_root);
4210 goto out;
4211 }
4212
4213 set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
4214 list_add(&reloc_root->root_list, &reloc_roots);
4215
4216 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4217 fs_root = btrfs_get_fs_root(fs_info,
4218 reloc_root->root_key.offset, false);
4219 if (IS_ERR(fs_root)) {
4220 ret = PTR_ERR(fs_root);
4221 if (ret != -ENOENT) {
4222 err = ret;
4223 goto out;
4224 }
4225 ret = mark_garbage_root(reloc_root);
4226 if (ret < 0) {
4227 err = ret;
4228 goto out;
4229 }
4230 } else {
4231 btrfs_put_root(fs_root);
4232 }
4233 }
4234
4235 if (key.offset == 0)
4236 break;
4237
4238 key.offset--;
4239 }
4240 btrfs_release_path(path);
4241
4242 if (list_empty(&reloc_roots))
4243 goto out;
4244
4245 rc = alloc_reloc_control(fs_info);
4246 if (!rc) {
4247 err = -ENOMEM;
4248 goto out;
4249 }
4250
4251 ret = reloc_chunk_start(fs_info);
4252 if (ret < 0) {
4253 err = ret;
4254 goto out_end;
4255 }
4256
4257 rc->extent_root = btrfs_extent_root(fs_info, 0);
4258
4259 set_reloc_control(rc);
4260
4261 trans = btrfs_join_transaction(rc->extent_root);
4262 if (IS_ERR(trans)) {
4263 err = PTR_ERR(trans);
4264 goto out_unset;
4265 }
4266
4267 rc->merge_reloc_tree = 1;
4268
4269 while (!list_empty(&reloc_roots)) {
4270 reloc_root = list_entry(reloc_roots.next,
4271 struct btrfs_root, root_list);
4272 list_del(&reloc_root->root_list);
4273
4274 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4275 list_add_tail(&reloc_root->root_list,
4276 &rc->reloc_roots);
4277 continue;
4278 }
4279
4280 fs_root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
4281 false);
4282 if (IS_ERR(fs_root)) {
4283 err = PTR_ERR(fs_root);
4284 list_add_tail(&reloc_root->root_list, &reloc_roots);
4285 btrfs_end_transaction(trans);
4286 goto out_unset;
4287 }
4288
4289 err = __add_reloc_root(reloc_root);
4290 ASSERT(err != -EEXIST);
4291 if (err) {
4292 list_add_tail(&reloc_root->root_list, &reloc_roots);
4293 btrfs_put_root(fs_root);
4294 btrfs_end_transaction(trans);
4295 goto out_unset;
4296 }
4297 fs_root->reloc_root = btrfs_grab_root(reloc_root);
4298 btrfs_put_root(fs_root);
4299 }
4300
4301 err = btrfs_commit_transaction(trans);
4302 if (err)
4303 goto out_unset;
4304
4305 merge_reloc_roots(rc);
4306
4307 unset_reloc_control(rc);
4308
4309 trans = btrfs_join_transaction(rc->extent_root);
4310 if (IS_ERR(trans)) {
4311 err = PTR_ERR(trans);
4312 goto out_clean;
4313 }
4314 err = btrfs_commit_transaction(trans);
4315out_clean:
4316 ret = clean_dirty_subvols(rc);
4317 if (ret < 0 && !err)
4318 err = ret;
4319out_unset:
4320 unset_reloc_control(rc);
4321out_end:
4322 reloc_chunk_end(fs_info);
4323 free_reloc_control(rc);
4324out:
4325 free_reloc_roots(&reloc_roots);
4326
4327 btrfs_free_path(path);
4328
4329 if (err == 0) {
4330 /* cleanup orphan inode in data relocation tree */
4331 fs_root = btrfs_grab_root(fs_info->data_reloc_root);
4332 ASSERT(fs_root);
4333 err = btrfs_orphan_cleanup(fs_root);
4334 btrfs_put_root(fs_root);
4335 }
4336 return err;
4337}
4338
4339/*
4340 * helper to add ordered checksum for data relocation.
4341 *
4342 * cloning checksum properly handles the nodatasum extents.
4343 * it also saves CPU time to re-calculate the checksum.
4344 */
4345int btrfs_reloc_clone_csums(struct btrfs_inode *inode, u64 file_pos, u64 len)
4346{
4347 struct btrfs_fs_info *fs_info = inode->root->fs_info;
4348 struct btrfs_root *csum_root;
4349 struct btrfs_ordered_sum *sums;
4350 struct btrfs_ordered_extent *ordered;
4351 int ret;
4352 u64 disk_bytenr;
4353 u64 new_bytenr;
4354 LIST_HEAD(list);
4355
4356 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4357 BUG_ON(ordered->file_offset != file_pos || ordered->num_bytes != len);
4358
4359 disk_bytenr = file_pos + inode->index_cnt;
4360 csum_root = btrfs_csum_root(fs_info, disk_bytenr);
4361 ret = btrfs_lookup_csums_list(csum_root, disk_bytenr,
4362 disk_bytenr + len - 1, &list, 0, false);
4363 if (ret)
4364 goto out;
4365
4366 while (!list_empty(&list)) {
4367 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4368 list_del_init(&sums->list);
4369
4370 /*
4371 * We need to offset the new_bytenr based on where the csum is.
4372 * We need to do this because we will read in entire prealloc
4373 * extents but we may have written to say the middle of the
4374 * prealloc extent, so we need to make sure the csum goes with
4375 * the right disk offset.
4376 *
4377 * We can do this because the data reloc inode refers strictly
4378 * to the on disk bytes, so we don't have to worry about
4379 * disk_len vs real len like with real inodes since it's all
4380 * disk length.
4381 */
4382 new_bytenr = ordered->disk_bytenr + sums->bytenr - disk_bytenr;
4383 sums->bytenr = new_bytenr;
4384
4385 btrfs_add_ordered_sum(ordered, sums);
4386 }
4387out:
4388 btrfs_put_ordered_extent(ordered);
4389 return ret;
4390}
4391
4392int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4393 struct btrfs_root *root, struct extent_buffer *buf,
4394 struct extent_buffer *cow)
4395{
4396 struct btrfs_fs_info *fs_info = root->fs_info;
4397 struct reloc_control *rc;
4398 struct btrfs_backref_node *node;
4399 int first_cow = 0;
4400 int level;
4401 int ret = 0;
4402
4403 rc = fs_info->reloc_ctl;
4404 if (!rc)
4405 return 0;
4406
4407 BUG_ON(rc->stage == UPDATE_DATA_PTRS && btrfs_is_data_reloc_root(root));
4408
4409 level = btrfs_header_level(buf);
4410 if (btrfs_header_generation(buf) <=
4411 btrfs_root_last_snapshot(&root->root_item))
4412 first_cow = 1;
4413
4414 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4415 rc->create_reloc_tree) {
4416 WARN_ON(!first_cow && level == 0);
4417
4418 node = rc->backref_cache.path[level];
4419 BUG_ON(node->bytenr != buf->start &&
4420 node->new_bytenr != buf->start);
4421
4422 btrfs_backref_drop_node_buffer(node);
4423 atomic_inc(&cow->refs);
4424 node->eb = cow;
4425 node->new_bytenr = cow->start;
4426
4427 if (!node->pending) {
4428 list_move_tail(&node->list,
4429 &rc->backref_cache.pending[level]);
4430 node->pending = 1;
4431 }
4432
4433 if (first_cow)
4434 mark_block_processed(rc, node);
4435
4436 if (first_cow && level > 0)
4437 rc->nodes_relocated += buf->len;
4438 }
4439
4440 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4441 ret = replace_file_extents(trans, rc, root, cow);
4442 return ret;
4443}
4444
4445/*
4446 * called before creating snapshot. it calculates metadata reservation
4447 * required for relocating tree blocks in the snapshot
4448 */
4449void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4450 u64 *bytes_to_reserve)
4451{
4452 struct btrfs_root *root = pending->root;
4453 struct reloc_control *rc = root->fs_info->reloc_ctl;
4454
4455 if (!rc || !have_reloc_root(root))
4456 return;
4457
4458 if (!rc->merge_reloc_tree)
4459 return;
4460
4461 root = root->reloc_root;
4462 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4463 /*
4464 * relocation is in the stage of merging trees. the space
4465 * used by merging a reloc tree is twice the size of
4466 * relocated tree nodes in the worst case. half for cowing
4467 * the reloc tree, half for cowing the fs tree. the space
4468 * used by cowing the reloc tree will be freed after the
4469 * tree is dropped. if we create snapshot, cowing the fs
4470 * tree may use more space than it frees. so we need
4471 * reserve extra space.
4472 */
4473 *bytes_to_reserve += rc->nodes_relocated;
4474}
4475
4476/*
4477 * called after snapshot is created. migrate block reservation
4478 * and create reloc root for the newly created snapshot
4479 *
4480 * This is similar to btrfs_init_reloc_root(), we come out of here with two
4481 * references held on the reloc_root, one for root->reloc_root and one for
4482 * rc->reloc_roots.
4483 */
4484int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4485 struct btrfs_pending_snapshot *pending)
4486{
4487 struct btrfs_root *root = pending->root;
4488 struct btrfs_root *reloc_root;
4489 struct btrfs_root *new_root;
4490 struct reloc_control *rc = root->fs_info->reloc_ctl;
4491 int ret;
4492
4493 if (!rc || !have_reloc_root(root))
4494 return 0;
4495
4496 rc = root->fs_info->reloc_ctl;
4497 rc->merging_rsv_size += rc->nodes_relocated;
4498
4499 if (rc->merge_reloc_tree) {
4500 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4501 rc->block_rsv,
4502 rc->nodes_relocated, true);
4503 if (ret)
4504 return ret;
4505 }
4506
4507 new_root = pending->snap;
4508 reloc_root = create_reloc_root(trans, root->reloc_root,
4509 new_root->root_key.objectid);
4510 if (IS_ERR(reloc_root))
4511 return PTR_ERR(reloc_root);
4512
4513 ret = __add_reloc_root(reloc_root);
4514 ASSERT(ret != -EEXIST);
4515 if (ret) {
4516 /* Pairs with create_reloc_root */
4517 btrfs_put_root(reloc_root);
4518 return ret;
4519 }
4520 new_root->reloc_root = btrfs_grab_root(reloc_root);
4521
4522 if (rc->create_reloc_tree)
4523 ret = clone_backref_node(trans, rc, root, reloc_root);
4524 return ret;
4525}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2009 Oracle. All rights reserved.
4 */
5
6#include <linux/sched.h>
7#include <linux/pagemap.h>
8#include <linux/writeback.h>
9#include <linux/blkdev.h>
10#include <linux/rbtree.h>
11#include <linux/slab.h>
12#include "ctree.h"
13#include "disk-io.h"
14#include "transaction.h"
15#include "volumes.h"
16#include "locking.h"
17#include "btrfs_inode.h"
18#include "async-thread.h"
19#include "free-space-cache.h"
20#include "inode-map.h"
21#include "qgroup.h"
22#include "print-tree.h"
23
24/*
25 * backref_node, mapping_node and tree_block start with this
26 */
27struct tree_entry {
28 struct rb_node rb_node;
29 u64 bytenr;
30};
31
32/*
33 * present a tree block in the backref cache
34 */
35struct backref_node {
36 struct rb_node rb_node;
37 u64 bytenr;
38
39 u64 new_bytenr;
40 /* objectid of tree block owner, can be not uptodate */
41 u64 owner;
42 /* link to pending, changed or detached list */
43 struct list_head list;
44 /* list of upper level blocks reference this block */
45 struct list_head upper;
46 /* list of child blocks in the cache */
47 struct list_head lower;
48 /* NULL if this node is not tree root */
49 struct btrfs_root *root;
50 /* extent buffer got by COW the block */
51 struct extent_buffer *eb;
52 /* level of tree block */
53 unsigned int level:8;
54 /* is the block in non-reference counted tree */
55 unsigned int cowonly:1;
56 /* 1 if no child node in the cache */
57 unsigned int lowest:1;
58 /* is the extent buffer locked */
59 unsigned int locked:1;
60 /* has the block been processed */
61 unsigned int processed:1;
62 /* have backrefs of this block been checked */
63 unsigned int checked:1;
64 /*
65 * 1 if corresponding block has been cowed but some upper
66 * level block pointers may not point to the new location
67 */
68 unsigned int pending:1;
69 /*
70 * 1 if the backref node isn't connected to any other
71 * backref node.
72 */
73 unsigned int detached:1;
74};
75
76/*
77 * present a block pointer in the backref cache
78 */
79struct backref_edge {
80 struct list_head list[2];
81 struct backref_node *node[2];
82};
83
84#define LOWER 0
85#define UPPER 1
86#define RELOCATION_RESERVED_NODES 256
87
88struct backref_cache {
89 /* red black tree of all backref nodes in the cache */
90 struct rb_root rb_root;
91 /* for passing backref nodes to btrfs_reloc_cow_block */
92 struct backref_node *path[BTRFS_MAX_LEVEL];
93 /*
94 * list of blocks that have been cowed but some block
95 * pointers in upper level blocks may not reflect the
96 * new location
97 */
98 struct list_head pending[BTRFS_MAX_LEVEL];
99 /* list of backref nodes with no child node */
100 struct list_head leaves;
101 /* list of blocks that have been cowed in current transaction */
102 struct list_head changed;
103 /* list of detached backref node. */
104 struct list_head detached;
105
106 u64 last_trans;
107
108 int nr_nodes;
109 int nr_edges;
110};
111
112/*
113 * map address of tree root to tree
114 */
115struct mapping_node {
116 struct rb_node rb_node;
117 u64 bytenr;
118 void *data;
119};
120
121struct mapping_tree {
122 struct rb_root rb_root;
123 spinlock_t lock;
124};
125
126/*
127 * present a tree block to process
128 */
129struct tree_block {
130 struct rb_node rb_node;
131 u64 bytenr;
132 struct btrfs_key key;
133 unsigned int level:8;
134 unsigned int key_ready:1;
135};
136
137#define MAX_EXTENTS 128
138
139struct file_extent_cluster {
140 u64 start;
141 u64 end;
142 u64 boundary[MAX_EXTENTS];
143 unsigned int nr;
144};
145
146struct reloc_control {
147 /* block group to relocate */
148 struct btrfs_block_group_cache *block_group;
149 /* extent tree */
150 struct btrfs_root *extent_root;
151 /* inode for moving data */
152 struct inode *data_inode;
153
154 struct btrfs_block_rsv *block_rsv;
155
156 struct backref_cache backref_cache;
157
158 struct file_extent_cluster cluster;
159 /* tree blocks have been processed */
160 struct extent_io_tree processed_blocks;
161 /* map start of tree root to corresponding reloc tree */
162 struct mapping_tree reloc_root_tree;
163 /* list of reloc trees */
164 struct list_head reloc_roots;
165 /* size of metadata reservation for merging reloc trees */
166 u64 merging_rsv_size;
167 /* size of relocated tree nodes */
168 u64 nodes_relocated;
169 /* reserved size for block group relocation*/
170 u64 reserved_bytes;
171
172 u64 search_start;
173 u64 extents_found;
174
175 unsigned int stage:8;
176 unsigned int create_reloc_tree:1;
177 unsigned int merge_reloc_tree:1;
178 unsigned int found_file_extent:1;
179};
180
181/* stages of data relocation */
182#define MOVE_DATA_EXTENTS 0
183#define UPDATE_DATA_PTRS 1
184
185static void remove_backref_node(struct backref_cache *cache,
186 struct backref_node *node);
187static void __mark_block_processed(struct reloc_control *rc,
188 struct backref_node *node);
189
190static void mapping_tree_init(struct mapping_tree *tree)
191{
192 tree->rb_root = RB_ROOT;
193 spin_lock_init(&tree->lock);
194}
195
196static void backref_cache_init(struct backref_cache *cache)
197{
198 int i;
199 cache->rb_root = RB_ROOT;
200 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
201 INIT_LIST_HEAD(&cache->pending[i]);
202 INIT_LIST_HEAD(&cache->changed);
203 INIT_LIST_HEAD(&cache->detached);
204 INIT_LIST_HEAD(&cache->leaves);
205}
206
207static void backref_cache_cleanup(struct backref_cache *cache)
208{
209 struct backref_node *node;
210 int i;
211
212 while (!list_empty(&cache->detached)) {
213 node = list_entry(cache->detached.next,
214 struct backref_node, list);
215 remove_backref_node(cache, node);
216 }
217
218 while (!list_empty(&cache->leaves)) {
219 node = list_entry(cache->leaves.next,
220 struct backref_node, lower);
221 remove_backref_node(cache, node);
222 }
223
224 cache->last_trans = 0;
225
226 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
227 ASSERT(list_empty(&cache->pending[i]));
228 ASSERT(list_empty(&cache->changed));
229 ASSERT(list_empty(&cache->detached));
230 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
231 ASSERT(!cache->nr_nodes);
232 ASSERT(!cache->nr_edges);
233}
234
235static struct backref_node *alloc_backref_node(struct backref_cache *cache)
236{
237 struct backref_node *node;
238
239 node = kzalloc(sizeof(*node), GFP_NOFS);
240 if (node) {
241 INIT_LIST_HEAD(&node->list);
242 INIT_LIST_HEAD(&node->upper);
243 INIT_LIST_HEAD(&node->lower);
244 RB_CLEAR_NODE(&node->rb_node);
245 cache->nr_nodes++;
246 }
247 return node;
248}
249
250static void free_backref_node(struct backref_cache *cache,
251 struct backref_node *node)
252{
253 if (node) {
254 cache->nr_nodes--;
255 kfree(node);
256 }
257}
258
259static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
260{
261 struct backref_edge *edge;
262
263 edge = kzalloc(sizeof(*edge), GFP_NOFS);
264 if (edge)
265 cache->nr_edges++;
266 return edge;
267}
268
269static void free_backref_edge(struct backref_cache *cache,
270 struct backref_edge *edge)
271{
272 if (edge) {
273 cache->nr_edges--;
274 kfree(edge);
275 }
276}
277
278static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
279 struct rb_node *node)
280{
281 struct rb_node **p = &root->rb_node;
282 struct rb_node *parent = NULL;
283 struct tree_entry *entry;
284
285 while (*p) {
286 parent = *p;
287 entry = rb_entry(parent, struct tree_entry, rb_node);
288
289 if (bytenr < entry->bytenr)
290 p = &(*p)->rb_left;
291 else if (bytenr > entry->bytenr)
292 p = &(*p)->rb_right;
293 else
294 return parent;
295 }
296
297 rb_link_node(node, parent, p);
298 rb_insert_color(node, root);
299 return NULL;
300}
301
302static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
303{
304 struct rb_node *n = root->rb_node;
305 struct tree_entry *entry;
306
307 while (n) {
308 entry = rb_entry(n, struct tree_entry, rb_node);
309
310 if (bytenr < entry->bytenr)
311 n = n->rb_left;
312 else if (bytenr > entry->bytenr)
313 n = n->rb_right;
314 else
315 return n;
316 }
317 return NULL;
318}
319
320static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
321{
322
323 struct btrfs_fs_info *fs_info = NULL;
324 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
325 rb_node);
326 if (bnode->root)
327 fs_info = bnode->root->fs_info;
328 btrfs_panic(fs_info, errno,
329 "Inconsistency in backref cache found at offset %llu",
330 bytenr);
331}
332
333/*
334 * walk up backref nodes until reach node presents tree root
335 */
336static struct backref_node *walk_up_backref(struct backref_node *node,
337 struct backref_edge *edges[],
338 int *index)
339{
340 struct backref_edge *edge;
341 int idx = *index;
342
343 while (!list_empty(&node->upper)) {
344 edge = list_entry(node->upper.next,
345 struct backref_edge, list[LOWER]);
346 edges[idx++] = edge;
347 node = edge->node[UPPER];
348 }
349 BUG_ON(node->detached);
350 *index = idx;
351 return node;
352}
353
354/*
355 * walk down backref nodes to find start of next reference path
356 */
357static struct backref_node *walk_down_backref(struct backref_edge *edges[],
358 int *index)
359{
360 struct backref_edge *edge;
361 struct backref_node *lower;
362 int idx = *index;
363
364 while (idx > 0) {
365 edge = edges[idx - 1];
366 lower = edge->node[LOWER];
367 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
368 idx--;
369 continue;
370 }
371 edge = list_entry(edge->list[LOWER].next,
372 struct backref_edge, list[LOWER]);
373 edges[idx - 1] = edge;
374 *index = idx;
375 return edge->node[UPPER];
376 }
377 *index = 0;
378 return NULL;
379}
380
381static void unlock_node_buffer(struct backref_node *node)
382{
383 if (node->locked) {
384 btrfs_tree_unlock(node->eb);
385 node->locked = 0;
386 }
387}
388
389static void drop_node_buffer(struct backref_node *node)
390{
391 if (node->eb) {
392 unlock_node_buffer(node);
393 free_extent_buffer(node->eb);
394 node->eb = NULL;
395 }
396}
397
398static void drop_backref_node(struct backref_cache *tree,
399 struct backref_node *node)
400{
401 BUG_ON(!list_empty(&node->upper));
402
403 drop_node_buffer(node);
404 list_del(&node->list);
405 list_del(&node->lower);
406 if (!RB_EMPTY_NODE(&node->rb_node))
407 rb_erase(&node->rb_node, &tree->rb_root);
408 free_backref_node(tree, node);
409}
410
411/*
412 * remove a backref node from the backref cache
413 */
414static void remove_backref_node(struct backref_cache *cache,
415 struct backref_node *node)
416{
417 struct backref_node *upper;
418 struct backref_edge *edge;
419
420 if (!node)
421 return;
422
423 BUG_ON(!node->lowest && !node->detached);
424 while (!list_empty(&node->upper)) {
425 edge = list_entry(node->upper.next, struct backref_edge,
426 list[LOWER]);
427 upper = edge->node[UPPER];
428 list_del(&edge->list[LOWER]);
429 list_del(&edge->list[UPPER]);
430 free_backref_edge(cache, edge);
431
432 if (RB_EMPTY_NODE(&upper->rb_node)) {
433 BUG_ON(!list_empty(&node->upper));
434 drop_backref_node(cache, node);
435 node = upper;
436 node->lowest = 1;
437 continue;
438 }
439 /*
440 * add the node to leaf node list if no other
441 * child block cached.
442 */
443 if (list_empty(&upper->lower)) {
444 list_add_tail(&upper->lower, &cache->leaves);
445 upper->lowest = 1;
446 }
447 }
448
449 drop_backref_node(cache, node);
450}
451
452static void update_backref_node(struct backref_cache *cache,
453 struct backref_node *node, u64 bytenr)
454{
455 struct rb_node *rb_node;
456 rb_erase(&node->rb_node, &cache->rb_root);
457 node->bytenr = bytenr;
458 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
459 if (rb_node)
460 backref_tree_panic(rb_node, -EEXIST, bytenr);
461}
462
463/*
464 * update backref cache after a transaction commit
465 */
466static int update_backref_cache(struct btrfs_trans_handle *trans,
467 struct backref_cache *cache)
468{
469 struct backref_node *node;
470 int level = 0;
471
472 if (cache->last_trans == 0) {
473 cache->last_trans = trans->transid;
474 return 0;
475 }
476
477 if (cache->last_trans == trans->transid)
478 return 0;
479
480 /*
481 * detached nodes are used to avoid unnecessary backref
482 * lookup. transaction commit changes the extent tree.
483 * so the detached nodes are no longer useful.
484 */
485 while (!list_empty(&cache->detached)) {
486 node = list_entry(cache->detached.next,
487 struct backref_node, list);
488 remove_backref_node(cache, node);
489 }
490
491 while (!list_empty(&cache->changed)) {
492 node = list_entry(cache->changed.next,
493 struct backref_node, list);
494 list_del_init(&node->list);
495 BUG_ON(node->pending);
496 update_backref_node(cache, node, node->new_bytenr);
497 }
498
499 /*
500 * some nodes can be left in the pending list if there were
501 * errors during processing the pending nodes.
502 */
503 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
504 list_for_each_entry(node, &cache->pending[level], list) {
505 BUG_ON(!node->pending);
506 if (node->bytenr == node->new_bytenr)
507 continue;
508 update_backref_node(cache, node, node->new_bytenr);
509 }
510 }
511
512 cache->last_trans = 0;
513 return 1;
514}
515
516
517static int should_ignore_root(struct btrfs_root *root)
518{
519 struct btrfs_root *reloc_root;
520
521 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
522 return 0;
523
524 reloc_root = root->reloc_root;
525 if (!reloc_root)
526 return 0;
527
528 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
529 root->fs_info->running_transaction->transid - 1)
530 return 0;
531 /*
532 * if there is reloc tree and it was created in previous
533 * transaction backref lookup can find the reloc tree,
534 * so backref node for the fs tree root is useless for
535 * relocation.
536 */
537 return 1;
538}
539/*
540 * find reloc tree by address of tree root
541 */
542static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
543 u64 bytenr)
544{
545 struct rb_node *rb_node;
546 struct mapping_node *node;
547 struct btrfs_root *root = NULL;
548
549 spin_lock(&rc->reloc_root_tree.lock);
550 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
551 if (rb_node) {
552 node = rb_entry(rb_node, struct mapping_node, rb_node);
553 root = (struct btrfs_root *)node->data;
554 }
555 spin_unlock(&rc->reloc_root_tree.lock);
556 return root;
557}
558
559static int is_cowonly_root(u64 root_objectid)
560{
561 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
562 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
563 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
564 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
565 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
566 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
567 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
568 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
569 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
570 return 1;
571 return 0;
572}
573
574static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
575 u64 root_objectid)
576{
577 struct btrfs_key key;
578
579 key.objectid = root_objectid;
580 key.type = BTRFS_ROOT_ITEM_KEY;
581 if (is_cowonly_root(root_objectid))
582 key.offset = 0;
583 else
584 key.offset = (u64)-1;
585
586 return btrfs_get_fs_root(fs_info, &key, false);
587}
588
589#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
590static noinline_for_stack
591struct btrfs_root *find_tree_root(struct reloc_control *rc,
592 struct extent_buffer *leaf,
593 struct btrfs_extent_ref_v0 *ref0)
594{
595 struct btrfs_root *root;
596 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
597 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
598
599 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
600
601 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
602 BUG_ON(IS_ERR(root));
603
604 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
605 generation != btrfs_root_generation(&root->root_item))
606 return NULL;
607
608 return root;
609}
610#endif
611
612static noinline_for_stack
613int find_inline_backref(struct extent_buffer *leaf, int slot,
614 unsigned long *ptr, unsigned long *end)
615{
616 struct btrfs_key key;
617 struct btrfs_extent_item *ei;
618 struct btrfs_tree_block_info *bi;
619 u32 item_size;
620
621 btrfs_item_key_to_cpu(leaf, &key, slot);
622
623 item_size = btrfs_item_size_nr(leaf, slot);
624#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
625 if (item_size < sizeof(*ei)) {
626 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
627 return 1;
628 }
629#endif
630 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
631 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
632 BTRFS_EXTENT_FLAG_TREE_BLOCK));
633
634 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
635 item_size <= sizeof(*ei) + sizeof(*bi)) {
636 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
637 return 1;
638 }
639 if (key.type == BTRFS_METADATA_ITEM_KEY &&
640 item_size <= sizeof(*ei)) {
641 WARN_ON(item_size < sizeof(*ei));
642 return 1;
643 }
644
645 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
646 bi = (struct btrfs_tree_block_info *)(ei + 1);
647 *ptr = (unsigned long)(bi + 1);
648 } else {
649 *ptr = (unsigned long)(ei + 1);
650 }
651 *end = (unsigned long)ei + item_size;
652 return 0;
653}
654
655/*
656 * build backref tree for a given tree block. root of the backref tree
657 * corresponds the tree block, leaves of the backref tree correspond
658 * roots of b-trees that reference the tree block.
659 *
660 * the basic idea of this function is check backrefs of a given block
661 * to find upper level blocks that reference the block, and then check
662 * backrefs of these upper level blocks recursively. the recursion stop
663 * when tree root is reached or backrefs for the block is cached.
664 *
665 * NOTE: if we find backrefs for a block are cached, we know backrefs
666 * for all upper level blocks that directly/indirectly reference the
667 * block are also cached.
668 */
669static noinline_for_stack
670struct backref_node *build_backref_tree(struct reloc_control *rc,
671 struct btrfs_key *node_key,
672 int level, u64 bytenr)
673{
674 struct backref_cache *cache = &rc->backref_cache;
675 struct btrfs_path *path1;
676 struct btrfs_path *path2;
677 struct extent_buffer *eb;
678 struct btrfs_root *root;
679 struct backref_node *cur;
680 struct backref_node *upper;
681 struct backref_node *lower;
682 struct backref_node *node = NULL;
683 struct backref_node *exist = NULL;
684 struct backref_edge *edge;
685 struct rb_node *rb_node;
686 struct btrfs_key key;
687 unsigned long end;
688 unsigned long ptr;
689 LIST_HEAD(list);
690 LIST_HEAD(useless);
691 int cowonly;
692 int ret;
693 int err = 0;
694 bool need_check = true;
695
696 path1 = btrfs_alloc_path();
697 path2 = btrfs_alloc_path();
698 if (!path1 || !path2) {
699 err = -ENOMEM;
700 goto out;
701 }
702 path1->reada = READA_FORWARD;
703 path2->reada = READA_FORWARD;
704
705 node = alloc_backref_node(cache);
706 if (!node) {
707 err = -ENOMEM;
708 goto out;
709 }
710
711 node->bytenr = bytenr;
712 node->level = level;
713 node->lowest = 1;
714 cur = node;
715again:
716 end = 0;
717 ptr = 0;
718 key.objectid = cur->bytenr;
719 key.type = BTRFS_METADATA_ITEM_KEY;
720 key.offset = (u64)-1;
721
722 path1->search_commit_root = 1;
723 path1->skip_locking = 1;
724 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
725 0, 0);
726 if (ret < 0) {
727 err = ret;
728 goto out;
729 }
730 ASSERT(ret);
731 ASSERT(path1->slots[0]);
732
733 path1->slots[0]--;
734
735 WARN_ON(cur->checked);
736 if (!list_empty(&cur->upper)) {
737 /*
738 * the backref was added previously when processing
739 * backref of type BTRFS_TREE_BLOCK_REF_KEY
740 */
741 ASSERT(list_is_singular(&cur->upper));
742 edge = list_entry(cur->upper.next, struct backref_edge,
743 list[LOWER]);
744 ASSERT(list_empty(&edge->list[UPPER]));
745 exist = edge->node[UPPER];
746 /*
747 * add the upper level block to pending list if we need
748 * check its backrefs
749 */
750 if (!exist->checked)
751 list_add_tail(&edge->list[UPPER], &list);
752 } else {
753 exist = NULL;
754 }
755
756 while (1) {
757 cond_resched();
758 eb = path1->nodes[0];
759
760 if (ptr >= end) {
761 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
762 ret = btrfs_next_leaf(rc->extent_root, path1);
763 if (ret < 0) {
764 err = ret;
765 goto out;
766 }
767 if (ret > 0)
768 break;
769 eb = path1->nodes[0];
770 }
771
772 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
773 if (key.objectid != cur->bytenr) {
774 WARN_ON(exist);
775 break;
776 }
777
778 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
779 key.type == BTRFS_METADATA_ITEM_KEY) {
780 ret = find_inline_backref(eb, path1->slots[0],
781 &ptr, &end);
782 if (ret)
783 goto next;
784 }
785 }
786
787 if (ptr < end) {
788 /* update key for inline back ref */
789 struct btrfs_extent_inline_ref *iref;
790 int type;
791 iref = (struct btrfs_extent_inline_ref *)ptr;
792 type = btrfs_get_extent_inline_ref_type(eb, iref,
793 BTRFS_REF_TYPE_BLOCK);
794 if (type == BTRFS_REF_TYPE_INVALID) {
795 err = -EINVAL;
796 goto out;
797 }
798 key.type = type;
799 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
800
801 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
802 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
803 }
804
805 if (exist &&
806 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
807 exist->owner == key.offset) ||
808 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
809 exist->bytenr == key.offset))) {
810 exist = NULL;
811 goto next;
812 }
813
814#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
815 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
816 key.type == BTRFS_EXTENT_REF_V0_KEY) {
817 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
818 struct btrfs_extent_ref_v0 *ref0;
819 ref0 = btrfs_item_ptr(eb, path1->slots[0],
820 struct btrfs_extent_ref_v0);
821 if (key.objectid == key.offset) {
822 root = find_tree_root(rc, eb, ref0);
823 if (root && !should_ignore_root(root))
824 cur->root = root;
825 else
826 list_add(&cur->list, &useless);
827 break;
828 }
829 if (is_cowonly_root(btrfs_ref_root_v0(eb,
830 ref0)))
831 cur->cowonly = 1;
832 }
833#else
834 ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
835 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
836#endif
837 if (key.objectid == key.offset) {
838 /*
839 * only root blocks of reloc trees use
840 * backref of this type.
841 */
842 root = find_reloc_root(rc, cur->bytenr);
843 ASSERT(root);
844 cur->root = root;
845 break;
846 }
847
848 edge = alloc_backref_edge(cache);
849 if (!edge) {
850 err = -ENOMEM;
851 goto out;
852 }
853 rb_node = tree_search(&cache->rb_root, key.offset);
854 if (!rb_node) {
855 upper = alloc_backref_node(cache);
856 if (!upper) {
857 free_backref_edge(cache, edge);
858 err = -ENOMEM;
859 goto out;
860 }
861 upper->bytenr = key.offset;
862 upper->level = cur->level + 1;
863 /*
864 * backrefs for the upper level block isn't
865 * cached, add the block to pending list
866 */
867 list_add_tail(&edge->list[UPPER], &list);
868 } else {
869 upper = rb_entry(rb_node, struct backref_node,
870 rb_node);
871 ASSERT(upper->checked);
872 INIT_LIST_HEAD(&edge->list[UPPER]);
873 }
874 list_add_tail(&edge->list[LOWER], &cur->upper);
875 edge->node[LOWER] = cur;
876 edge->node[UPPER] = upper;
877
878 goto next;
879 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
880 goto next;
881 }
882
883 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
884 root = read_fs_root(rc->extent_root->fs_info, key.offset);
885 if (IS_ERR(root)) {
886 err = PTR_ERR(root);
887 goto out;
888 }
889
890 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
891 cur->cowonly = 1;
892
893 if (btrfs_root_level(&root->root_item) == cur->level) {
894 /* tree root */
895 ASSERT(btrfs_root_bytenr(&root->root_item) ==
896 cur->bytenr);
897 if (should_ignore_root(root))
898 list_add(&cur->list, &useless);
899 else
900 cur->root = root;
901 break;
902 }
903
904 level = cur->level + 1;
905
906 /*
907 * searching the tree to find upper level blocks
908 * reference the block.
909 */
910 path2->search_commit_root = 1;
911 path2->skip_locking = 1;
912 path2->lowest_level = level;
913 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
914 path2->lowest_level = 0;
915 if (ret < 0) {
916 err = ret;
917 goto out;
918 }
919 if (ret > 0 && path2->slots[level] > 0)
920 path2->slots[level]--;
921
922 eb = path2->nodes[level];
923 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
924 cur->bytenr) {
925 btrfs_err(root->fs_info,
926 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
927 cur->bytenr, level - 1, root->objectid,
928 node_key->objectid, node_key->type,
929 node_key->offset);
930 err = -ENOENT;
931 goto out;
932 }
933 lower = cur;
934 need_check = true;
935 for (; level < BTRFS_MAX_LEVEL; level++) {
936 if (!path2->nodes[level]) {
937 ASSERT(btrfs_root_bytenr(&root->root_item) ==
938 lower->bytenr);
939 if (should_ignore_root(root))
940 list_add(&lower->list, &useless);
941 else
942 lower->root = root;
943 break;
944 }
945
946 edge = alloc_backref_edge(cache);
947 if (!edge) {
948 err = -ENOMEM;
949 goto out;
950 }
951
952 eb = path2->nodes[level];
953 rb_node = tree_search(&cache->rb_root, eb->start);
954 if (!rb_node) {
955 upper = alloc_backref_node(cache);
956 if (!upper) {
957 free_backref_edge(cache, edge);
958 err = -ENOMEM;
959 goto out;
960 }
961 upper->bytenr = eb->start;
962 upper->owner = btrfs_header_owner(eb);
963 upper->level = lower->level + 1;
964 if (!test_bit(BTRFS_ROOT_REF_COWS,
965 &root->state))
966 upper->cowonly = 1;
967
968 /*
969 * if we know the block isn't shared
970 * we can void checking its backrefs.
971 */
972 if (btrfs_block_can_be_shared(root, eb))
973 upper->checked = 0;
974 else
975 upper->checked = 1;
976
977 /*
978 * add the block to pending list if we
979 * need check its backrefs, we only do this once
980 * while walking up a tree as we will catch
981 * anything else later on.
982 */
983 if (!upper->checked && need_check) {
984 need_check = false;
985 list_add_tail(&edge->list[UPPER],
986 &list);
987 } else {
988 if (upper->checked)
989 need_check = true;
990 INIT_LIST_HEAD(&edge->list[UPPER]);
991 }
992 } else {
993 upper = rb_entry(rb_node, struct backref_node,
994 rb_node);
995 ASSERT(upper->checked);
996 INIT_LIST_HEAD(&edge->list[UPPER]);
997 if (!upper->owner)
998 upper->owner = btrfs_header_owner(eb);
999 }
1000 list_add_tail(&edge->list[LOWER], &lower->upper);
1001 edge->node[LOWER] = lower;
1002 edge->node[UPPER] = upper;
1003
1004 if (rb_node)
1005 break;
1006 lower = upper;
1007 upper = NULL;
1008 }
1009 btrfs_release_path(path2);
1010next:
1011 if (ptr < end) {
1012 ptr += btrfs_extent_inline_ref_size(key.type);
1013 if (ptr >= end) {
1014 WARN_ON(ptr > end);
1015 ptr = 0;
1016 end = 0;
1017 }
1018 }
1019 if (ptr >= end)
1020 path1->slots[0]++;
1021 }
1022 btrfs_release_path(path1);
1023
1024 cur->checked = 1;
1025 WARN_ON(exist);
1026
1027 /* the pending list isn't empty, take the first block to process */
1028 if (!list_empty(&list)) {
1029 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1030 list_del_init(&edge->list[UPPER]);
1031 cur = edge->node[UPPER];
1032 goto again;
1033 }
1034
1035 /*
1036 * everything goes well, connect backref nodes and insert backref nodes
1037 * into the cache.
1038 */
1039 ASSERT(node->checked);
1040 cowonly = node->cowonly;
1041 if (!cowonly) {
1042 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1043 &node->rb_node);
1044 if (rb_node)
1045 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1046 list_add_tail(&node->lower, &cache->leaves);
1047 }
1048
1049 list_for_each_entry(edge, &node->upper, list[LOWER])
1050 list_add_tail(&edge->list[UPPER], &list);
1051
1052 while (!list_empty(&list)) {
1053 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1054 list_del_init(&edge->list[UPPER]);
1055 upper = edge->node[UPPER];
1056 if (upper->detached) {
1057 list_del(&edge->list[LOWER]);
1058 lower = edge->node[LOWER];
1059 free_backref_edge(cache, edge);
1060 if (list_empty(&lower->upper))
1061 list_add(&lower->list, &useless);
1062 continue;
1063 }
1064
1065 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1066 if (upper->lowest) {
1067 list_del_init(&upper->lower);
1068 upper->lowest = 0;
1069 }
1070
1071 list_add_tail(&edge->list[UPPER], &upper->lower);
1072 continue;
1073 }
1074
1075 if (!upper->checked) {
1076 /*
1077 * Still want to blow up for developers since this is a
1078 * logic bug.
1079 */
1080 ASSERT(0);
1081 err = -EINVAL;
1082 goto out;
1083 }
1084 if (cowonly != upper->cowonly) {
1085 ASSERT(0);
1086 err = -EINVAL;
1087 goto out;
1088 }
1089
1090 if (!cowonly) {
1091 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1092 &upper->rb_node);
1093 if (rb_node)
1094 backref_tree_panic(rb_node, -EEXIST,
1095 upper->bytenr);
1096 }
1097
1098 list_add_tail(&edge->list[UPPER], &upper->lower);
1099
1100 list_for_each_entry(edge, &upper->upper, list[LOWER])
1101 list_add_tail(&edge->list[UPPER], &list);
1102 }
1103 /*
1104 * process useless backref nodes. backref nodes for tree leaves
1105 * are deleted from the cache. backref nodes for upper level
1106 * tree blocks are left in the cache to avoid unnecessary backref
1107 * lookup.
1108 */
1109 while (!list_empty(&useless)) {
1110 upper = list_entry(useless.next, struct backref_node, list);
1111 list_del_init(&upper->list);
1112 ASSERT(list_empty(&upper->upper));
1113 if (upper == node)
1114 node = NULL;
1115 if (upper->lowest) {
1116 list_del_init(&upper->lower);
1117 upper->lowest = 0;
1118 }
1119 while (!list_empty(&upper->lower)) {
1120 edge = list_entry(upper->lower.next,
1121 struct backref_edge, list[UPPER]);
1122 list_del(&edge->list[UPPER]);
1123 list_del(&edge->list[LOWER]);
1124 lower = edge->node[LOWER];
1125 free_backref_edge(cache, edge);
1126
1127 if (list_empty(&lower->upper))
1128 list_add(&lower->list, &useless);
1129 }
1130 __mark_block_processed(rc, upper);
1131 if (upper->level > 0) {
1132 list_add(&upper->list, &cache->detached);
1133 upper->detached = 1;
1134 } else {
1135 rb_erase(&upper->rb_node, &cache->rb_root);
1136 free_backref_node(cache, upper);
1137 }
1138 }
1139out:
1140 btrfs_free_path(path1);
1141 btrfs_free_path(path2);
1142 if (err) {
1143 while (!list_empty(&useless)) {
1144 lower = list_entry(useless.next,
1145 struct backref_node, list);
1146 list_del_init(&lower->list);
1147 }
1148 while (!list_empty(&list)) {
1149 edge = list_first_entry(&list, struct backref_edge,
1150 list[UPPER]);
1151 list_del(&edge->list[UPPER]);
1152 list_del(&edge->list[LOWER]);
1153 lower = edge->node[LOWER];
1154 upper = edge->node[UPPER];
1155 free_backref_edge(cache, edge);
1156
1157 /*
1158 * Lower is no longer linked to any upper backref nodes
1159 * and isn't in the cache, we can free it ourselves.
1160 */
1161 if (list_empty(&lower->upper) &&
1162 RB_EMPTY_NODE(&lower->rb_node))
1163 list_add(&lower->list, &useless);
1164
1165 if (!RB_EMPTY_NODE(&upper->rb_node))
1166 continue;
1167
1168 /* Add this guy's upper edges to the list to process */
1169 list_for_each_entry(edge, &upper->upper, list[LOWER])
1170 list_add_tail(&edge->list[UPPER], &list);
1171 if (list_empty(&upper->upper))
1172 list_add(&upper->list, &useless);
1173 }
1174
1175 while (!list_empty(&useless)) {
1176 lower = list_entry(useless.next,
1177 struct backref_node, list);
1178 list_del_init(&lower->list);
1179 if (lower == node)
1180 node = NULL;
1181 free_backref_node(cache, lower);
1182 }
1183
1184 free_backref_node(cache, node);
1185 return ERR_PTR(err);
1186 }
1187 ASSERT(!node || !node->detached);
1188 return node;
1189}
1190
1191/*
1192 * helper to add backref node for the newly created snapshot.
1193 * the backref node is created by cloning backref node that
1194 * corresponds to root of source tree
1195 */
1196static int clone_backref_node(struct btrfs_trans_handle *trans,
1197 struct reloc_control *rc,
1198 struct btrfs_root *src,
1199 struct btrfs_root *dest)
1200{
1201 struct btrfs_root *reloc_root = src->reloc_root;
1202 struct backref_cache *cache = &rc->backref_cache;
1203 struct backref_node *node = NULL;
1204 struct backref_node *new_node;
1205 struct backref_edge *edge;
1206 struct backref_edge *new_edge;
1207 struct rb_node *rb_node;
1208
1209 if (cache->last_trans > 0)
1210 update_backref_cache(trans, cache);
1211
1212 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1213 if (rb_node) {
1214 node = rb_entry(rb_node, struct backref_node, rb_node);
1215 if (node->detached)
1216 node = NULL;
1217 else
1218 BUG_ON(node->new_bytenr != reloc_root->node->start);
1219 }
1220
1221 if (!node) {
1222 rb_node = tree_search(&cache->rb_root,
1223 reloc_root->commit_root->start);
1224 if (rb_node) {
1225 node = rb_entry(rb_node, struct backref_node,
1226 rb_node);
1227 BUG_ON(node->detached);
1228 }
1229 }
1230
1231 if (!node)
1232 return 0;
1233
1234 new_node = alloc_backref_node(cache);
1235 if (!new_node)
1236 return -ENOMEM;
1237
1238 new_node->bytenr = dest->node->start;
1239 new_node->level = node->level;
1240 new_node->lowest = node->lowest;
1241 new_node->checked = 1;
1242 new_node->root = dest;
1243
1244 if (!node->lowest) {
1245 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1246 new_edge = alloc_backref_edge(cache);
1247 if (!new_edge)
1248 goto fail;
1249
1250 new_edge->node[UPPER] = new_node;
1251 new_edge->node[LOWER] = edge->node[LOWER];
1252 list_add_tail(&new_edge->list[UPPER],
1253 &new_node->lower);
1254 }
1255 } else {
1256 list_add_tail(&new_node->lower, &cache->leaves);
1257 }
1258
1259 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1260 &new_node->rb_node);
1261 if (rb_node)
1262 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1263
1264 if (!new_node->lowest) {
1265 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1266 list_add_tail(&new_edge->list[LOWER],
1267 &new_edge->node[LOWER]->upper);
1268 }
1269 }
1270 return 0;
1271fail:
1272 while (!list_empty(&new_node->lower)) {
1273 new_edge = list_entry(new_node->lower.next,
1274 struct backref_edge, list[UPPER]);
1275 list_del(&new_edge->list[UPPER]);
1276 free_backref_edge(cache, new_edge);
1277 }
1278 free_backref_node(cache, new_node);
1279 return -ENOMEM;
1280}
1281
1282/*
1283 * helper to add 'address of tree root -> reloc tree' mapping
1284 */
1285static int __must_check __add_reloc_root(struct btrfs_root *root)
1286{
1287 struct btrfs_fs_info *fs_info = root->fs_info;
1288 struct rb_node *rb_node;
1289 struct mapping_node *node;
1290 struct reloc_control *rc = fs_info->reloc_ctl;
1291
1292 node = kmalloc(sizeof(*node), GFP_NOFS);
1293 if (!node)
1294 return -ENOMEM;
1295
1296 node->bytenr = root->node->start;
1297 node->data = root;
1298
1299 spin_lock(&rc->reloc_root_tree.lock);
1300 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1301 node->bytenr, &node->rb_node);
1302 spin_unlock(&rc->reloc_root_tree.lock);
1303 if (rb_node) {
1304 btrfs_panic(fs_info, -EEXIST,
1305 "Duplicate root found for start=%llu while inserting into relocation tree",
1306 node->bytenr);
1307 }
1308
1309 list_add_tail(&root->root_list, &rc->reloc_roots);
1310 return 0;
1311}
1312
1313/*
1314 * helper to delete the 'address of tree root -> reloc tree'
1315 * mapping
1316 */
1317static void __del_reloc_root(struct btrfs_root *root)
1318{
1319 struct btrfs_fs_info *fs_info = root->fs_info;
1320 struct rb_node *rb_node;
1321 struct mapping_node *node = NULL;
1322 struct reloc_control *rc = fs_info->reloc_ctl;
1323
1324 spin_lock(&rc->reloc_root_tree.lock);
1325 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1326 root->node->start);
1327 if (rb_node) {
1328 node = rb_entry(rb_node, struct mapping_node, rb_node);
1329 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1330 }
1331 spin_unlock(&rc->reloc_root_tree.lock);
1332
1333 if (!node)
1334 return;
1335 BUG_ON((struct btrfs_root *)node->data != root);
1336
1337 spin_lock(&fs_info->trans_lock);
1338 list_del_init(&root->root_list);
1339 spin_unlock(&fs_info->trans_lock);
1340 kfree(node);
1341}
1342
1343/*
1344 * helper to update the 'address of tree root -> reloc tree'
1345 * mapping
1346 */
1347static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1348{
1349 struct btrfs_fs_info *fs_info = root->fs_info;
1350 struct rb_node *rb_node;
1351 struct mapping_node *node = NULL;
1352 struct reloc_control *rc = fs_info->reloc_ctl;
1353
1354 spin_lock(&rc->reloc_root_tree.lock);
1355 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1356 root->node->start);
1357 if (rb_node) {
1358 node = rb_entry(rb_node, struct mapping_node, rb_node);
1359 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1360 }
1361 spin_unlock(&rc->reloc_root_tree.lock);
1362
1363 if (!node)
1364 return 0;
1365 BUG_ON((struct btrfs_root *)node->data != root);
1366
1367 spin_lock(&rc->reloc_root_tree.lock);
1368 node->bytenr = new_bytenr;
1369 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1370 node->bytenr, &node->rb_node);
1371 spin_unlock(&rc->reloc_root_tree.lock);
1372 if (rb_node)
1373 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1374 return 0;
1375}
1376
1377static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1378 struct btrfs_root *root, u64 objectid)
1379{
1380 struct btrfs_fs_info *fs_info = root->fs_info;
1381 struct btrfs_root *reloc_root;
1382 struct extent_buffer *eb;
1383 struct btrfs_root_item *root_item;
1384 struct btrfs_key root_key;
1385 int ret;
1386
1387 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1388 BUG_ON(!root_item);
1389
1390 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1391 root_key.type = BTRFS_ROOT_ITEM_KEY;
1392 root_key.offset = objectid;
1393
1394 if (root->root_key.objectid == objectid) {
1395 u64 commit_root_gen;
1396
1397 /* called by btrfs_init_reloc_root */
1398 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1399 BTRFS_TREE_RELOC_OBJECTID);
1400 BUG_ON(ret);
1401 /*
1402 * Set the last_snapshot field to the generation of the commit
1403 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1404 * correctly (returns true) when the relocation root is created
1405 * either inside the critical section of a transaction commit
1406 * (through transaction.c:qgroup_account_snapshot()) and when
1407 * it's created before the transaction commit is started.
1408 */
1409 commit_root_gen = btrfs_header_generation(root->commit_root);
1410 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1411 } else {
1412 /*
1413 * called by btrfs_reloc_post_snapshot_hook.
1414 * the source tree is a reloc tree, all tree blocks
1415 * modified after it was created have RELOC flag
1416 * set in their headers. so it's OK to not update
1417 * the 'last_snapshot'.
1418 */
1419 ret = btrfs_copy_root(trans, root, root->node, &eb,
1420 BTRFS_TREE_RELOC_OBJECTID);
1421 BUG_ON(ret);
1422 }
1423
1424 memcpy(root_item, &root->root_item, sizeof(*root_item));
1425 btrfs_set_root_bytenr(root_item, eb->start);
1426 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1427 btrfs_set_root_generation(root_item, trans->transid);
1428
1429 if (root->root_key.objectid == objectid) {
1430 btrfs_set_root_refs(root_item, 0);
1431 memset(&root_item->drop_progress, 0,
1432 sizeof(struct btrfs_disk_key));
1433 root_item->drop_level = 0;
1434 }
1435
1436 btrfs_tree_unlock(eb);
1437 free_extent_buffer(eb);
1438
1439 ret = btrfs_insert_root(trans, fs_info->tree_root,
1440 &root_key, root_item);
1441 BUG_ON(ret);
1442 kfree(root_item);
1443
1444 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1445 BUG_ON(IS_ERR(reloc_root));
1446 reloc_root->last_trans = trans->transid;
1447 return reloc_root;
1448}
1449
1450/*
1451 * create reloc tree for a given fs tree. reloc tree is just a
1452 * snapshot of the fs tree with special root objectid.
1453 */
1454int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1455 struct btrfs_root *root)
1456{
1457 struct btrfs_fs_info *fs_info = root->fs_info;
1458 struct btrfs_root *reloc_root;
1459 struct reloc_control *rc = fs_info->reloc_ctl;
1460 struct btrfs_block_rsv *rsv;
1461 int clear_rsv = 0;
1462 int ret;
1463
1464 if (root->reloc_root) {
1465 reloc_root = root->reloc_root;
1466 reloc_root->last_trans = trans->transid;
1467 return 0;
1468 }
1469
1470 if (!rc || !rc->create_reloc_tree ||
1471 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1472 return 0;
1473
1474 if (!trans->reloc_reserved) {
1475 rsv = trans->block_rsv;
1476 trans->block_rsv = rc->block_rsv;
1477 clear_rsv = 1;
1478 }
1479 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1480 if (clear_rsv)
1481 trans->block_rsv = rsv;
1482
1483 ret = __add_reloc_root(reloc_root);
1484 BUG_ON(ret < 0);
1485 root->reloc_root = reloc_root;
1486 return 0;
1487}
1488
1489/*
1490 * update root item of reloc tree
1491 */
1492int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1493 struct btrfs_root *root)
1494{
1495 struct btrfs_fs_info *fs_info = root->fs_info;
1496 struct btrfs_root *reloc_root;
1497 struct btrfs_root_item *root_item;
1498 int ret;
1499
1500 if (!root->reloc_root)
1501 goto out;
1502
1503 reloc_root = root->reloc_root;
1504 root_item = &reloc_root->root_item;
1505
1506 if (fs_info->reloc_ctl->merge_reloc_tree &&
1507 btrfs_root_refs(root_item) == 0) {
1508 root->reloc_root = NULL;
1509 __del_reloc_root(reloc_root);
1510 }
1511
1512 if (reloc_root->commit_root != reloc_root->node) {
1513 btrfs_set_root_node(root_item, reloc_root->node);
1514 free_extent_buffer(reloc_root->commit_root);
1515 reloc_root->commit_root = btrfs_root_node(reloc_root);
1516 }
1517
1518 ret = btrfs_update_root(trans, fs_info->tree_root,
1519 &reloc_root->root_key, root_item);
1520 BUG_ON(ret);
1521
1522out:
1523 return 0;
1524}
1525
1526/*
1527 * helper to find first cached inode with inode number >= objectid
1528 * in a subvolume
1529 */
1530static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1531{
1532 struct rb_node *node;
1533 struct rb_node *prev;
1534 struct btrfs_inode *entry;
1535 struct inode *inode;
1536
1537 spin_lock(&root->inode_lock);
1538again:
1539 node = root->inode_tree.rb_node;
1540 prev = NULL;
1541 while (node) {
1542 prev = node;
1543 entry = rb_entry(node, struct btrfs_inode, rb_node);
1544
1545 if (objectid < btrfs_ino(entry))
1546 node = node->rb_left;
1547 else if (objectid > btrfs_ino(entry))
1548 node = node->rb_right;
1549 else
1550 break;
1551 }
1552 if (!node) {
1553 while (prev) {
1554 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1555 if (objectid <= btrfs_ino(entry)) {
1556 node = prev;
1557 break;
1558 }
1559 prev = rb_next(prev);
1560 }
1561 }
1562 while (node) {
1563 entry = rb_entry(node, struct btrfs_inode, rb_node);
1564 inode = igrab(&entry->vfs_inode);
1565 if (inode) {
1566 spin_unlock(&root->inode_lock);
1567 return inode;
1568 }
1569
1570 objectid = btrfs_ino(entry) + 1;
1571 if (cond_resched_lock(&root->inode_lock))
1572 goto again;
1573
1574 node = rb_next(node);
1575 }
1576 spin_unlock(&root->inode_lock);
1577 return NULL;
1578}
1579
1580static int in_block_group(u64 bytenr,
1581 struct btrfs_block_group_cache *block_group)
1582{
1583 if (bytenr >= block_group->key.objectid &&
1584 bytenr < block_group->key.objectid + block_group->key.offset)
1585 return 1;
1586 return 0;
1587}
1588
1589/*
1590 * get new location of data
1591 */
1592static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1593 u64 bytenr, u64 num_bytes)
1594{
1595 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1596 struct btrfs_path *path;
1597 struct btrfs_file_extent_item *fi;
1598 struct extent_buffer *leaf;
1599 int ret;
1600
1601 path = btrfs_alloc_path();
1602 if (!path)
1603 return -ENOMEM;
1604
1605 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1606 ret = btrfs_lookup_file_extent(NULL, root, path,
1607 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1608 if (ret < 0)
1609 goto out;
1610 if (ret > 0) {
1611 ret = -ENOENT;
1612 goto out;
1613 }
1614
1615 leaf = path->nodes[0];
1616 fi = btrfs_item_ptr(leaf, path->slots[0],
1617 struct btrfs_file_extent_item);
1618
1619 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1620 btrfs_file_extent_compression(leaf, fi) ||
1621 btrfs_file_extent_encryption(leaf, fi) ||
1622 btrfs_file_extent_other_encoding(leaf, fi));
1623
1624 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1625 ret = -EINVAL;
1626 goto out;
1627 }
1628
1629 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1630 ret = 0;
1631out:
1632 btrfs_free_path(path);
1633 return ret;
1634}
1635
1636/*
1637 * update file extent items in the tree leaf to point to
1638 * the new locations.
1639 */
1640static noinline_for_stack
1641int replace_file_extents(struct btrfs_trans_handle *trans,
1642 struct reloc_control *rc,
1643 struct btrfs_root *root,
1644 struct extent_buffer *leaf)
1645{
1646 struct btrfs_fs_info *fs_info = root->fs_info;
1647 struct btrfs_key key;
1648 struct btrfs_file_extent_item *fi;
1649 struct inode *inode = NULL;
1650 u64 parent;
1651 u64 bytenr;
1652 u64 new_bytenr = 0;
1653 u64 num_bytes;
1654 u64 end;
1655 u32 nritems;
1656 u32 i;
1657 int ret = 0;
1658 int first = 1;
1659 int dirty = 0;
1660
1661 if (rc->stage != UPDATE_DATA_PTRS)
1662 return 0;
1663
1664 /* reloc trees always use full backref */
1665 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1666 parent = leaf->start;
1667 else
1668 parent = 0;
1669
1670 nritems = btrfs_header_nritems(leaf);
1671 for (i = 0; i < nritems; i++) {
1672 cond_resched();
1673 btrfs_item_key_to_cpu(leaf, &key, i);
1674 if (key.type != BTRFS_EXTENT_DATA_KEY)
1675 continue;
1676 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1677 if (btrfs_file_extent_type(leaf, fi) ==
1678 BTRFS_FILE_EXTENT_INLINE)
1679 continue;
1680 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1681 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1682 if (bytenr == 0)
1683 continue;
1684 if (!in_block_group(bytenr, rc->block_group))
1685 continue;
1686
1687 /*
1688 * if we are modifying block in fs tree, wait for readpage
1689 * to complete and drop the extent cache
1690 */
1691 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1692 if (first) {
1693 inode = find_next_inode(root, key.objectid);
1694 first = 0;
1695 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1696 btrfs_add_delayed_iput(inode);
1697 inode = find_next_inode(root, key.objectid);
1698 }
1699 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1700 end = key.offset +
1701 btrfs_file_extent_num_bytes(leaf, fi);
1702 WARN_ON(!IS_ALIGNED(key.offset,
1703 fs_info->sectorsize));
1704 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1705 end--;
1706 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1707 key.offset, end);
1708 if (!ret)
1709 continue;
1710
1711 btrfs_drop_extent_cache(BTRFS_I(inode),
1712 key.offset, end, 1);
1713 unlock_extent(&BTRFS_I(inode)->io_tree,
1714 key.offset, end);
1715 }
1716 }
1717
1718 ret = get_new_location(rc->data_inode, &new_bytenr,
1719 bytenr, num_bytes);
1720 if (ret) {
1721 /*
1722 * Don't have to abort since we've not changed anything
1723 * in the file extent yet.
1724 */
1725 break;
1726 }
1727
1728 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1729 dirty = 1;
1730
1731 key.offset -= btrfs_file_extent_offset(leaf, fi);
1732 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1733 num_bytes, parent,
1734 btrfs_header_owner(leaf),
1735 key.objectid, key.offset);
1736 if (ret) {
1737 btrfs_abort_transaction(trans, ret);
1738 break;
1739 }
1740
1741 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1742 parent, btrfs_header_owner(leaf),
1743 key.objectid, key.offset);
1744 if (ret) {
1745 btrfs_abort_transaction(trans, ret);
1746 break;
1747 }
1748 }
1749 if (dirty)
1750 btrfs_mark_buffer_dirty(leaf);
1751 if (inode)
1752 btrfs_add_delayed_iput(inode);
1753 return ret;
1754}
1755
1756static noinline_for_stack
1757int memcmp_node_keys(struct extent_buffer *eb, int slot,
1758 struct btrfs_path *path, int level)
1759{
1760 struct btrfs_disk_key key1;
1761 struct btrfs_disk_key key2;
1762 btrfs_node_key(eb, &key1, slot);
1763 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1764 return memcmp(&key1, &key2, sizeof(key1));
1765}
1766
1767/*
1768 * try to replace tree blocks in fs tree with the new blocks
1769 * in reloc tree. tree blocks haven't been modified since the
1770 * reloc tree was create can be replaced.
1771 *
1772 * if a block was replaced, level of the block + 1 is returned.
1773 * if no block got replaced, 0 is returned. if there are other
1774 * errors, a negative error number is returned.
1775 */
1776static noinline_for_stack
1777int replace_path(struct btrfs_trans_handle *trans,
1778 struct btrfs_root *dest, struct btrfs_root *src,
1779 struct btrfs_path *path, struct btrfs_key *next_key,
1780 int lowest_level, int max_level)
1781{
1782 struct btrfs_fs_info *fs_info = dest->fs_info;
1783 struct extent_buffer *eb;
1784 struct extent_buffer *parent;
1785 struct btrfs_key key;
1786 u64 old_bytenr;
1787 u64 new_bytenr;
1788 u64 old_ptr_gen;
1789 u64 new_ptr_gen;
1790 u64 last_snapshot;
1791 u32 blocksize;
1792 int cow = 0;
1793 int level;
1794 int ret;
1795 int slot;
1796
1797 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1798 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1799
1800 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1801again:
1802 slot = path->slots[lowest_level];
1803 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1804
1805 eb = btrfs_lock_root_node(dest);
1806 btrfs_set_lock_blocking(eb);
1807 level = btrfs_header_level(eb);
1808
1809 if (level < lowest_level) {
1810 btrfs_tree_unlock(eb);
1811 free_extent_buffer(eb);
1812 return 0;
1813 }
1814
1815 if (cow) {
1816 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1817 BUG_ON(ret);
1818 }
1819 btrfs_set_lock_blocking(eb);
1820
1821 if (next_key) {
1822 next_key->objectid = (u64)-1;
1823 next_key->type = (u8)-1;
1824 next_key->offset = (u64)-1;
1825 }
1826
1827 parent = eb;
1828 while (1) {
1829 struct btrfs_key first_key;
1830
1831 level = btrfs_header_level(parent);
1832 BUG_ON(level < lowest_level);
1833
1834 ret = btrfs_bin_search(parent, &key, level, &slot);
1835 if (ret && slot > 0)
1836 slot--;
1837
1838 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1839 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1840
1841 old_bytenr = btrfs_node_blockptr(parent, slot);
1842 blocksize = fs_info->nodesize;
1843 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1844 btrfs_node_key_to_cpu(parent, &first_key, slot);
1845
1846 if (level <= max_level) {
1847 eb = path->nodes[level];
1848 new_bytenr = btrfs_node_blockptr(eb,
1849 path->slots[level]);
1850 new_ptr_gen = btrfs_node_ptr_generation(eb,
1851 path->slots[level]);
1852 } else {
1853 new_bytenr = 0;
1854 new_ptr_gen = 0;
1855 }
1856
1857 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1858 ret = level;
1859 break;
1860 }
1861
1862 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1863 memcmp_node_keys(parent, slot, path, level)) {
1864 if (level <= lowest_level) {
1865 ret = 0;
1866 break;
1867 }
1868
1869 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1870 level - 1, &first_key);
1871 if (IS_ERR(eb)) {
1872 ret = PTR_ERR(eb);
1873 break;
1874 } else if (!extent_buffer_uptodate(eb)) {
1875 ret = -EIO;
1876 free_extent_buffer(eb);
1877 break;
1878 }
1879 btrfs_tree_lock(eb);
1880 if (cow) {
1881 ret = btrfs_cow_block(trans, dest, eb, parent,
1882 slot, &eb);
1883 BUG_ON(ret);
1884 }
1885 btrfs_set_lock_blocking(eb);
1886
1887 btrfs_tree_unlock(parent);
1888 free_extent_buffer(parent);
1889
1890 parent = eb;
1891 continue;
1892 }
1893
1894 if (!cow) {
1895 btrfs_tree_unlock(parent);
1896 free_extent_buffer(parent);
1897 cow = 1;
1898 goto again;
1899 }
1900
1901 btrfs_node_key_to_cpu(path->nodes[level], &key,
1902 path->slots[level]);
1903 btrfs_release_path(path);
1904
1905 path->lowest_level = level;
1906 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1907 path->lowest_level = 0;
1908 BUG_ON(ret);
1909
1910 /*
1911 * Info qgroup to trace both subtrees.
1912 *
1913 * We must trace both trees.
1914 * 1) Tree reloc subtree
1915 * If not traced, we will leak data numbers
1916 * 2) Fs subtree
1917 * If not traced, we will double count old data
1918 * and tree block numbers, if current trans doesn't free
1919 * data reloc tree inode.
1920 */
1921 ret = btrfs_qgroup_trace_subtree(trans, src, parent,
1922 btrfs_header_generation(parent),
1923 btrfs_header_level(parent));
1924 if (ret < 0)
1925 break;
1926 ret = btrfs_qgroup_trace_subtree(trans, dest,
1927 path->nodes[level],
1928 btrfs_header_generation(path->nodes[level]),
1929 btrfs_header_level(path->nodes[level]));
1930 if (ret < 0)
1931 break;
1932
1933 /*
1934 * swap blocks in fs tree and reloc tree.
1935 */
1936 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1937 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1938 btrfs_mark_buffer_dirty(parent);
1939
1940 btrfs_set_node_blockptr(path->nodes[level],
1941 path->slots[level], old_bytenr);
1942 btrfs_set_node_ptr_generation(path->nodes[level],
1943 path->slots[level], old_ptr_gen);
1944 btrfs_mark_buffer_dirty(path->nodes[level]);
1945
1946 ret = btrfs_inc_extent_ref(trans, src, old_bytenr,
1947 blocksize, path->nodes[level]->start,
1948 src->root_key.objectid, level - 1, 0);
1949 BUG_ON(ret);
1950 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr,
1951 blocksize, 0, dest->root_key.objectid,
1952 level - 1, 0);
1953 BUG_ON(ret);
1954
1955 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1956 path->nodes[level]->start,
1957 src->root_key.objectid, level - 1, 0);
1958 BUG_ON(ret);
1959
1960 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1961 0, dest->root_key.objectid, level - 1,
1962 0);
1963 BUG_ON(ret);
1964
1965 btrfs_unlock_up_safe(path, 0);
1966
1967 ret = level;
1968 break;
1969 }
1970 btrfs_tree_unlock(parent);
1971 free_extent_buffer(parent);
1972 return ret;
1973}
1974
1975/*
1976 * helper to find next relocated block in reloc tree
1977 */
1978static noinline_for_stack
1979int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1980 int *level)
1981{
1982 struct extent_buffer *eb;
1983 int i;
1984 u64 last_snapshot;
1985 u32 nritems;
1986
1987 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1988
1989 for (i = 0; i < *level; i++) {
1990 free_extent_buffer(path->nodes[i]);
1991 path->nodes[i] = NULL;
1992 }
1993
1994 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1995 eb = path->nodes[i];
1996 nritems = btrfs_header_nritems(eb);
1997 while (path->slots[i] + 1 < nritems) {
1998 path->slots[i]++;
1999 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
2000 last_snapshot)
2001 continue;
2002
2003 *level = i;
2004 return 0;
2005 }
2006 free_extent_buffer(path->nodes[i]);
2007 path->nodes[i] = NULL;
2008 }
2009 return 1;
2010}
2011
2012/*
2013 * walk down reloc tree to find relocated block of lowest level
2014 */
2015static noinline_for_stack
2016int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2017 int *level)
2018{
2019 struct btrfs_fs_info *fs_info = root->fs_info;
2020 struct extent_buffer *eb = NULL;
2021 int i;
2022 u64 bytenr;
2023 u64 ptr_gen = 0;
2024 u64 last_snapshot;
2025 u32 nritems;
2026
2027 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2028
2029 for (i = *level; i > 0; i--) {
2030 struct btrfs_key first_key;
2031
2032 eb = path->nodes[i];
2033 nritems = btrfs_header_nritems(eb);
2034 while (path->slots[i] < nritems) {
2035 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2036 if (ptr_gen > last_snapshot)
2037 break;
2038 path->slots[i]++;
2039 }
2040 if (path->slots[i] >= nritems) {
2041 if (i == *level)
2042 break;
2043 *level = i + 1;
2044 return 0;
2045 }
2046 if (i == 1) {
2047 *level = i;
2048 return 0;
2049 }
2050
2051 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2052 btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
2053 eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
2054 &first_key);
2055 if (IS_ERR(eb)) {
2056 return PTR_ERR(eb);
2057 } else if (!extent_buffer_uptodate(eb)) {
2058 free_extent_buffer(eb);
2059 return -EIO;
2060 }
2061 BUG_ON(btrfs_header_level(eb) != i - 1);
2062 path->nodes[i - 1] = eb;
2063 path->slots[i - 1] = 0;
2064 }
2065 return 1;
2066}
2067
2068/*
2069 * invalidate extent cache for file extents whose key in range of
2070 * [min_key, max_key)
2071 */
2072static int invalidate_extent_cache(struct btrfs_root *root,
2073 struct btrfs_key *min_key,
2074 struct btrfs_key *max_key)
2075{
2076 struct btrfs_fs_info *fs_info = root->fs_info;
2077 struct inode *inode = NULL;
2078 u64 objectid;
2079 u64 start, end;
2080 u64 ino;
2081
2082 objectid = min_key->objectid;
2083 while (1) {
2084 cond_resched();
2085 iput(inode);
2086
2087 if (objectid > max_key->objectid)
2088 break;
2089
2090 inode = find_next_inode(root, objectid);
2091 if (!inode)
2092 break;
2093 ino = btrfs_ino(BTRFS_I(inode));
2094
2095 if (ino > max_key->objectid) {
2096 iput(inode);
2097 break;
2098 }
2099
2100 objectid = ino + 1;
2101 if (!S_ISREG(inode->i_mode))
2102 continue;
2103
2104 if (unlikely(min_key->objectid == ino)) {
2105 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2106 continue;
2107 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2108 start = 0;
2109 else {
2110 start = min_key->offset;
2111 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2112 }
2113 } else {
2114 start = 0;
2115 }
2116
2117 if (unlikely(max_key->objectid == ino)) {
2118 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2119 continue;
2120 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2121 end = (u64)-1;
2122 } else {
2123 if (max_key->offset == 0)
2124 continue;
2125 end = max_key->offset;
2126 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2127 end--;
2128 }
2129 } else {
2130 end = (u64)-1;
2131 }
2132
2133 /* the lock_extent waits for readpage to complete */
2134 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2135 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2136 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2137 }
2138 return 0;
2139}
2140
2141static int find_next_key(struct btrfs_path *path, int level,
2142 struct btrfs_key *key)
2143
2144{
2145 while (level < BTRFS_MAX_LEVEL) {
2146 if (!path->nodes[level])
2147 break;
2148 if (path->slots[level] + 1 <
2149 btrfs_header_nritems(path->nodes[level])) {
2150 btrfs_node_key_to_cpu(path->nodes[level], key,
2151 path->slots[level] + 1);
2152 return 0;
2153 }
2154 level++;
2155 }
2156 return 1;
2157}
2158
2159/*
2160 * merge the relocated tree blocks in reloc tree with corresponding
2161 * fs tree.
2162 */
2163static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2164 struct btrfs_root *root)
2165{
2166 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2167 LIST_HEAD(inode_list);
2168 struct btrfs_key key;
2169 struct btrfs_key next_key;
2170 struct btrfs_trans_handle *trans = NULL;
2171 struct btrfs_root *reloc_root;
2172 struct btrfs_root_item *root_item;
2173 struct btrfs_path *path;
2174 struct extent_buffer *leaf;
2175 int level;
2176 int max_level;
2177 int replaced = 0;
2178 int ret;
2179 int err = 0;
2180 u32 min_reserved;
2181
2182 path = btrfs_alloc_path();
2183 if (!path)
2184 return -ENOMEM;
2185 path->reada = READA_FORWARD;
2186
2187 reloc_root = root->reloc_root;
2188 root_item = &reloc_root->root_item;
2189
2190 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2191 level = btrfs_root_level(root_item);
2192 extent_buffer_get(reloc_root->node);
2193 path->nodes[level] = reloc_root->node;
2194 path->slots[level] = 0;
2195 } else {
2196 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2197
2198 level = root_item->drop_level;
2199 BUG_ON(level == 0);
2200 path->lowest_level = level;
2201 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2202 path->lowest_level = 0;
2203 if (ret < 0) {
2204 btrfs_free_path(path);
2205 return ret;
2206 }
2207
2208 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2209 path->slots[level]);
2210 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2211
2212 btrfs_unlock_up_safe(path, 0);
2213 }
2214
2215 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2216 memset(&next_key, 0, sizeof(next_key));
2217
2218 while (1) {
2219 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2220 BTRFS_RESERVE_FLUSH_ALL);
2221 if (ret) {
2222 err = ret;
2223 goto out;
2224 }
2225 trans = btrfs_start_transaction(root, 0);
2226 if (IS_ERR(trans)) {
2227 err = PTR_ERR(trans);
2228 trans = NULL;
2229 goto out;
2230 }
2231 trans->block_rsv = rc->block_rsv;
2232
2233 replaced = 0;
2234 max_level = level;
2235
2236 ret = walk_down_reloc_tree(reloc_root, path, &level);
2237 if (ret < 0) {
2238 err = ret;
2239 goto out;
2240 }
2241 if (ret > 0)
2242 break;
2243
2244 if (!find_next_key(path, level, &key) &&
2245 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2246 ret = 0;
2247 } else {
2248 ret = replace_path(trans, root, reloc_root, path,
2249 &next_key, level, max_level);
2250 }
2251 if (ret < 0) {
2252 err = ret;
2253 goto out;
2254 }
2255
2256 if (ret > 0) {
2257 level = ret;
2258 btrfs_node_key_to_cpu(path->nodes[level], &key,
2259 path->slots[level]);
2260 replaced = 1;
2261 }
2262
2263 ret = walk_up_reloc_tree(reloc_root, path, &level);
2264 if (ret > 0)
2265 break;
2266
2267 BUG_ON(level == 0);
2268 /*
2269 * save the merging progress in the drop_progress.
2270 * this is OK since root refs == 1 in this case.
2271 */
2272 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2273 path->slots[level]);
2274 root_item->drop_level = level;
2275
2276 btrfs_end_transaction_throttle(trans);
2277 trans = NULL;
2278
2279 btrfs_btree_balance_dirty(fs_info);
2280
2281 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2282 invalidate_extent_cache(root, &key, &next_key);
2283 }
2284
2285 /*
2286 * handle the case only one block in the fs tree need to be
2287 * relocated and the block is tree root.
2288 */
2289 leaf = btrfs_lock_root_node(root);
2290 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2291 btrfs_tree_unlock(leaf);
2292 free_extent_buffer(leaf);
2293 if (ret < 0)
2294 err = ret;
2295out:
2296 btrfs_free_path(path);
2297
2298 if (err == 0) {
2299 memset(&root_item->drop_progress, 0,
2300 sizeof(root_item->drop_progress));
2301 root_item->drop_level = 0;
2302 btrfs_set_root_refs(root_item, 0);
2303 btrfs_update_reloc_root(trans, root);
2304 }
2305
2306 if (trans)
2307 btrfs_end_transaction_throttle(trans);
2308
2309 btrfs_btree_balance_dirty(fs_info);
2310
2311 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2312 invalidate_extent_cache(root, &key, &next_key);
2313
2314 return err;
2315}
2316
2317static noinline_for_stack
2318int prepare_to_merge(struct reloc_control *rc, int err)
2319{
2320 struct btrfs_root *root = rc->extent_root;
2321 struct btrfs_fs_info *fs_info = root->fs_info;
2322 struct btrfs_root *reloc_root;
2323 struct btrfs_trans_handle *trans;
2324 LIST_HEAD(reloc_roots);
2325 u64 num_bytes = 0;
2326 int ret;
2327
2328 mutex_lock(&fs_info->reloc_mutex);
2329 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2330 rc->merging_rsv_size += rc->nodes_relocated * 2;
2331 mutex_unlock(&fs_info->reloc_mutex);
2332
2333again:
2334 if (!err) {
2335 num_bytes = rc->merging_rsv_size;
2336 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2337 BTRFS_RESERVE_FLUSH_ALL);
2338 if (ret)
2339 err = ret;
2340 }
2341
2342 trans = btrfs_join_transaction(rc->extent_root);
2343 if (IS_ERR(trans)) {
2344 if (!err)
2345 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2346 num_bytes);
2347 return PTR_ERR(trans);
2348 }
2349
2350 if (!err) {
2351 if (num_bytes != rc->merging_rsv_size) {
2352 btrfs_end_transaction(trans);
2353 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2354 num_bytes);
2355 goto again;
2356 }
2357 }
2358
2359 rc->merge_reloc_tree = 1;
2360
2361 while (!list_empty(&rc->reloc_roots)) {
2362 reloc_root = list_entry(rc->reloc_roots.next,
2363 struct btrfs_root, root_list);
2364 list_del_init(&reloc_root->root_list);
2365
2366 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2367 BUG_ON(IS_ERR(root));
2368 BUG_ON(root->reloc_root != reloc_root);
2369
2370 /*
2371 * set reference count to 1, so btrfs_recover_relocation
2372 * knows it should resumes merging
2373 */
2374 if (!err)
2375 btrfs_set_root_refs(&reloc_root->root_item, 1);
2376 btrfs_update_reloc_root(trans, root);
2377
2378 list_add(&reloc_root->root_list, &reloc_roots);
2379 }
2380
2381 list_splice(&reloc_roots, &rc->reloc_roots);
2382
2383 if (!err)
2384 btrfs_commit_transaction(trans);
2385 else
2386 btrfs_end_transaction(trans);
2387 return err;
2388}
2389
2390static noinline_for_stack
2391void free_reloc_roots(struct list_head *list)
2392{
2393 struct btrfs_root *reloc_root;
2394
2395 while (!list_empty(list)) {
2396 reloc_root = list_entry(list->next, struct btrfs_root,
2397 root_list);
2398 __del_reloc_root(reloc_root);
2399 free_extent_buffer(reloc_root->node);
2400 free_extent_buffer(reloc_root->commit_root);
2401 reloc_root->node = NULL;
2402 reloc_root->commit_root = NULL;
2403 }
2404}
2405
2406static noinline_for_stack
2407void merge_reloc_roots(struct reloc_control *rc)
2408{
2409 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2410 struct btrfs_root *root;
2411 struct btrfs_root *reloc_root;
2412 LIST_HEAD(reloc_roots);
2413 int found = 0;
2414 int ret = 0;
2415again:
2416 root = rc->extent_root;
2417
2418 /*
2419 * this serializes us with btrfs_record_root_in_transaction,
2420 * we have to make sure nobody is in the middle of
2421 * adding their roots to the list while we are
2422 * doing this splice
2423 */
2424 mutex_lock(&fs_info->reloc_mutex);
2425 list_splice_init(&rc->reloc_roots, &reloc_roots);
2426 mutex_unlock(&fs_info->reloc_mutex);
2427
2428 while (!list_empty(&reloc_roots)) {
2429 found = 1;
2430 reloc_root = list_entry(reloc_roots.next,
2431 struct btrfs_root, root_list);
2432
2433 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2434 root = read_fs_root(fs_info,
2435 reloc_root->root_key.offset);
2436 BUG_ON(IS_ERR(root));
2437 BUG_ON(root->reloc_root != reloc_root);
2438
2439 ret = merge_reloc_root(rc, root);
2440 if (ret) {
2441 if (list_empty(&reloc_root->root_list))
2442 list_add_tail(&reloc_root->root_list,
2443 &reloc_roots);
2444 goto out;
2445 }
2446 } else {
2447 list_del_init(&reloc_root->root_list);
2448 }
2449
2450 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2451 if (ret < 0) {
2452 if (list_empty(&reloc_root->root_list))
2453 list_add_tail(&reloc_root->root_list,
2454 &reloc_roots);
2455 goto out;
2456 }
2457 }
2458
2459 if (found) {
2460 found = 0;
2461 goto again;
2462 }
2463out:
2464 if (ret) {
2465 btrfs_handle_fs_error(fs_info, ret, NULL);
2466 if (!list_empty(&reloc_roots))
2467 free_reloc_roots(&reloc_roots);
2468
2469 /* new reloc root may be added */
2470 mutex_lock(&fs_info->reloc_mutex);
2471 list_splice_init(&rc->reloc_roots, &reloc_roots);
2472 mutex_unlock(&fs_info->reloc_mutex);
2473 if (!list_empty(&reloc_roots))
2474 free_reloc_roots(&reloc_roots);
2475 }
2476
2477 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2478}
2479
2480static void free_block_list(struct rb_root *blocks)
2481{
2482 struct tree_block *block;
2483 struct rb_node *rb_node;
2484 while ((rb_node = rb_first(blocks))) {
2485 block = rb_entry(rb_node, struct tree_block, rb_node);
2486 rb_erase(rb_node, blocks);
2487 kfree(block);
2488 }
2489}
2490
2491static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2492 struct btrfs_root *reloc_root)
2493{
2494 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2495 struct btrfs_root *root;
2496
2497 if (reloc_root->last_trans == trans->transid)
2498 return 0;
2499
2500 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2501 BUG_ON(IS_ERR(root));
2502 BUG_ON(root->reloc_root != reloc_root);
2503
2504 return btrfs_record_root_in_trans(trans, root);
2505}
2506
2507static noinline_for_stack
2508struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2509 struct reloc_control *rc,
2510 struct backref_node *node,
2511 struct backref_edge *edges[])
2512{
2513 struct backref_node *next;
2514 struct btrfs_root *root;
2515 int index = 0;
2516
2517 next = node;
2518 while (1) {
2519 cond_resched();
2520 next = walk_up_backref(next, edges, &index);
2521 root = next->root;
2522 BUG_ON(!root);
2523 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2524
2525 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2526 record_reloc_root_in_trans(trans, root);
2527 break;
2528 }
2529
2530 btrfs_record_root_in_trans(trans, root);
2531 root = root->reloc_root;
2532
2533 if (next->new_bytenr != root->node->start) {
2534 BUG_ON(next->new_bytenr);
2535 BUG_ON(!list_empty(&next->list));
2536 next->new_bytenr = root->node->start;
2537 next->root = root;
2538 list_add_tail(&next->list,
2539 &rc->backref_cache.changed);
2540 __mark_block_processed(rc, next);
2541 break;
2542 }
2543
2544 WARN_ON(1);
2545 root = NULL;
2546 next = walk_down_backref(edges, &index);
2547 if (!next || next->level <= node->level)
2548 break;
2549 }
2550 if (!root)
2551 return NULL;
2552
2553 next = node;
2554 /* setup backref node path for btrfs_reloc_cow_block */
2555 while (1) {
2556 rc->backref_cache.path[next->level] = next;
2557 if (--index < 0)
2558 break;
2559 next = edges[index]->node[UPPER];
2560 }
2561 return root;
2562}
2563
2564/*
2565 * select a tree root for relocation. return NULL if the block
2566 * is reference counted. we should use do_relocation() in this
2567 * case. return a tree root pointer if the block isn't reference
2568 * counted. return -ENOENT if the block is root of reloc tree.
2569 */
2570static noinline_for_stack
2571struct btrfs_root *select_one_root(struct backref_node *node)
2572{
2573 struct backref_node *next;
2574 struct btrfs_root *root;
2575 struct btrfs_root *fs_root = NULL;
2576 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2577 int index = 0;
2578
2579 next = node;
2580 while (1) {
2581 cond_resched();
2582 next = walk_up_backref(next, edges, &index);
2583 root = next->root;
2584 BUG_ON(!root);
2585
2586 /* no other choice for non-references counted tree */
2587 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2588 return root;
2589
2590 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2591 fs_root = root;
2592
2593 if (next != node)
2594 return NULL;
2595
2596 next = walk_down_backref(edges, &index);
2597 if (!next || next->level <= node->level)
2598 break;
2599 }
2600
2601 if (!fs_root)
2602 return ERR_PTR(-ENOENT);
2603 return fs_root;
2604}
2605
2606static noinline_for_stack
2607u64 calcu_metadata_size(struct reloc_control *rc,
2608 struct backref_node *node, int reserve)
2609{
2610 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2611 struct backref_node *next = node;
2612 struct backref_edge *edge;
2613 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2614 u64 num_bytes = 0;
2615 int index = 0;
2616
2617 BUG_ON(reserve && node->processed);
2618
2619 while (next) {
2620 cond_resched();
2621 while (1) {
2622 if (next->processed && (reserve || next != node))
2623 break;
2624
2625 num_bytes += fs_info->nodesize;
2626
2627 if (list_empty(&next->upper))
2628 break;
2629
2630 edge = list_entry(next->upper.next,
2631 struct backref_edge, list[LOWER]);
2632 edges[index++] = edge;
2633 next = edge->node[UPPER];
2634 }
2635 next = walk_down_backref(edges, &index);
2636 }
2637 return num_bytes;
2638}
2639
2640static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2641 struct reloc_control *rc,
2642 struct backref_node *node)
2643{
2644 struct btrfs_root *root = rc->extent_root;
2645 struct btrfs_fs_info *fs_info = root->fs_info;
2646 u64 num_bytes;
2647 int ret;
2648 u64 tmp;
2649
2650 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2651
2652 trans->block_rsv = rc->block_rsv;
2653 rc->reserved_bytes += num_bytes;
2654
2655 /*
2656 * We are under a transaction here so we can only do limited flushing.
2657 * If we get an enospc just kick back -EAGAIN so we know to drop the
2658 * transaction and try to refill when we can flush all the things.
2659 */
2660 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2661 BTRFS_RESERVE_FLUSH_LIMIT);
2662 if (ret) {
2663 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2664 while (tmp <= rc->reserved_bytes)
2665 tmp <<= 1;
2666 /*
2667 * only one thread can access block_rsv at this point,
2668 * so we don't need hold lock to protect block_rsv.
2669 * we expand more reservation size here to allow enough
2670 * space for relocation and we will return eailer in
2671 * enospc case.
2672 */
2673 rc->block_rsv->size = tmp + fs_info->nodesize *
2674 RELOCATION_RESERVED_NODES;
2675 return -EAGAIN;
2676 }
2677
2678 return 0;
2679}
2680
2681/*
2682 * relocate a block tree, and then update pointers in upper level
2683 * blocks that reference the block to point to the new location.
2684 *
2685 * if called by link_to_upper, the block has already been relocated.
2686 * in that case this function just updates pointers.
2687 */
2688static int do_relocation(struct btrfs_trans_handle *trans,
2689 struct reloc_control *rc,
2690 struct backref_node *node,
2691 struct btrfs_key *key,
2692 struct btrfs_path *path, int lowest)
2693{
2694 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2695 struct backref_node *upper;
2696 struct backref_edge *edge;
2697 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2698 struct btrfs_root *root;
2699 struct extent_buffer *eb;
2700 u32 blocksize;
2701 u64 bytenr;
2702 u64 generation;
2703 int slot;
2704 int ret;
2705 int err = 0;
2706
2707 BUG_ON(lowest && node->eb);
2708
2709 path->lowest_level = node->level + 1;
2710 rc->backref_cache.path[node->level] = node;
2711 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2712 struct btrfs_key first_key;
2713
2714 cond_resched();
2715
2716 upper = edge->node[UPPER];
2717 root = select_reloc_root(trans, rc, upper, edges);
2718 BUG_ON(!root);
2719
2720 if (upper->eb && !upper->locked) {
2721 if (!lowest) {
2722 ret = btrfs_bin_search(upper->eb, key,
2723 upper->level, &slot);
2724 BUG_ON(ret);
2725 bytenr = btrfs_node_blockptr(upper->eb, slot);
2726 if (node->eb->start == bytenr)
2727 goto next;
2728 }
2729 drop_node_buffer(upper);
2730 }
2731
2732 if (!upper->eb) {
2733 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2734 if (ret) {
2735 if (ret < 0)
2736 err = ret;
2737 else
2738 err = -ENOENT;
2739
2740 btrfs_release_path(path);
2741 break;
2742 }
2743
2744 if (!upper->eb) {
2745 upper->eb = path->nodes[upper->level];
2746 path->nodes[upper->level] = NULL;
2747 } else {
2748 BUG_ON(upper->eb != path->nodes[upper->level]);
2749 }
2750
2751 upper->locked = 1;
2752 path->locks[upper->level] = 0;
2753
2754 slot = path->slots[upper->level];
2755 btrfs_release_path(path);
2756 } else {
2757 ret = btrfs_bin_search(upper->eb, key, upper->level,
2758 &slot);
2759 BUG_ON(ret);
2760 }
2761
2762 bytenr = btrfs_node_blockptr(upper->eb, slot);
2763 if (lowest) {
2764 if (bytenr != node->bytenr) {
2765 btrfs_err(root->fs_info,
2766 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2767 bytenr, node->bytenr, slot,
2768 upper->eb->start);
2769 err = -EIO;
2770 goto next;
2771 }
2772 } else {
2773 if (node->eb->start == bytenr)
2774 goto next;
2775 }
2776
2777 blocksize = root->fs_info->nodesize;
2778 generation = btrfs_node_ptr_generation(upper->eb, slot);
2779 btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
2780 eb = read_tree_block(fs_info, bytenr, generation,
2781 upper->level - 1, &first_key);
2782 if (IS_ERR(eb)) {
2783 err = PTR_ERR(eb);
2784 goto next;
2785 } else if (!extent_buffer_uptodate(eb)) {
2786 free_extent_buffer(eb);
2787 err = -EIO;
2788 goto next;
2789 }
2790 btrfs_tree_lock(eb);
2791 btrfs_set_lock_blocking(eb);
2792
2793 if (!node->eb) {
2794 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2795 slot, &eb);
2796 btrfs_tree_unlock(eb);
2797 free_extent_buffer(eb);
2798 if (ret < 0) {
2799 err = ret;
2800 goto next;
2801 }
2802 BUG_ON(node->eb != eb);
2803 } else {
2804 btrfs_set_node_blockptr(upper->eb, slot,
2805 node->eb->start);
2806 btrfs_set_node_ptr_generation(upper->eb, slot,
2807 trans->transid);
2808 btrfs_mark_buffer_dirty(upper->eb);
2809
2810 ret = btrfs_inc_extent_ref(trans, root,
2811 node->eb->start, blocksize,
2812 upper->eb->start,
2813 btrfs_header_owner(upper->eb),
2814 node->level, 0);
2815 BUG_ON(ret);
2816
2817 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2818 BUG_ON(ret);
2819 }
2820next:
2821 if (!upper->pending)
2822 drop_node_buffer(upper);
2823 else
2824 unlock_node_buffer(upper);
2825 if (err)
2826 break;
2827 }
2828
2829 if (!err && node->pending) {
2830 drop_node_buffer(node);
2831 list_move_tail(&node->list, &rc->backref_cache.changed);
2832 node->pending = 0;
2833 }
2834
2835 path->lowest_level = 0;
2836 BUG_ON(err == -ENOSPC);
2837 return err;
2838}
2839
2840static int link_to_upper(struct btrfs_trans_handle *trans,
2841 struct reloc_control *rc,
2842 struct backref_node *node,
2843 struct btrfs_path *path)
2844{
2845 struct btrfs_key key;
2846
2847 btrfs_node_key_to_cpu(node->eb, &key, 0);
2848 return do_relocation(trans, rc, node, &key, path, 0);
2849}
2850
2851static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2852 struct reloc_control *rc,
2853 struct btrfs_path *path, int err)
2854{
2855 LIST_HEAD(list);
2856 struct backref_cache *cache = &rc->backref_cache;
2857 struct backref_node *node;
2858 int level;
2859 int ret;
2860
2861 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2862 while (!list_empty(&cache->pending[level])) {
2863 node = list_entry(cache->pending[level].next,
2864 struct backref_node, list);
2865 list_move_tail(&node->list, &list);
2866 BUG_ON(!node->pending);
2867
2868 if (!err) {
2869 ret = link_to_upper(trans, rc, node, path);
2870 if (ret < 0)
2871 err = ret;
2872 }
2873 }
2874 list_splice_init(&list, &cache->pending[level]);
2875 }
2876 return err;
2877}
2878
2879static void mark_block_processed(struct reloc_control *rc,
2880 u64 bytenr, u32 blocksize)
2881{
2882 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2883 EXTENT_DIRTY);
2884}
2885
2886static void __mark_block_processed(struct reloc_control *rc,
2887 struct backref_node *node)
2888{
2889 u32 blocksize;
2890 if (node->level == 0 ||
2891 in_block_group(node->bytenr, rc->block_group)) {
2892 blocksize = rc->extent_root->fs_info->nodesize;
2893 mark_block_processed(rc, node->bytenr, blocksize);
2894 }
2895 node->processed = 1;
2896}
2897
2898/*
2899 * mark a block and all blocks directly/indirectly reference the block
2900 * as processed.
2901 */
2902static void update_processed_blocks(struct reloc_control *rc,
2903 struct backref_node *node)
2904{
2905 struct backref_node *next = node;
2906 struct backref_edge *edge;
2907 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2908 int index = 0;
2909
2910 while (next) {
2911 cond_resched();
2912 while (1) {
2913 if (next->processed)
2914 break;
2915
2916 __mark_block_processed(rc, next);
2917
2918 if (list_empty(&next->upper))
2919 break;
2920
2921 edge = list_entry(next->upper.next,
2922 struct backref_edge, list[LOWER]);
2923 edges[index++] = edge;
2924 next = edge->node[UPPER];
2925 }
2926 next = walk_down_backref(edges, &index);
2927 }
2928}
2929
2930static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2931{
2932 u32 blocksize = rc->extent_root->fs_info->nodesize;
2933
2934 if (test_range_bit(&rc->processed_blocks, bytenr,
2935 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2936 return 1;
2937 return 0;
2938}
2939
2940static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2941 struct tree_block *block)
2942{
2943 struct extent_buffer *eb;
2944
2945 BUG_ON(block->key_ready);
2946 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
2947 block->level, NULL);
2948 if (IS_ERR(eb)) {
2949 return PTR_ERR(eb);
2950 } else if (!extent_buffer_uptodate(eb)) {
2951 free_extent_buffer(eb);
2952 return -EIO;
2953 }
2954 WARN_ON(btrfs_header_level(eb) != block->level);
2955 if (block->level == 0)
2956 btrfs_item_key_to_cpu(eb, &block->key, 0);
2957 else
2958 btrfs_node_key_to_cpu(eb, &block->key, 0);
2959 free_extent_buffer(eb);
2960 block->key_ready = 1;
2961 return 0;
2962}
2963
2964/*
2965 * helper function to relocate a tree block
2966 */
2967static int relocate_tree_block(struct btrfs_trans_handle *trans,
2968 struct reloc_control *rc,
2969 struct backref_node *node,
2970 struct btrfs_key *key,
2971 struct btrfs_path *path)
2972{
2973 struct btrfs_root *root;
2974 int ret = 0;
2975
2976 if (!node)
2977 return 0;
2978
2979 BUG_ON(node->processed);
2980 root = select_one_root(node);
2981 if (root == ERR_PTR(-ENOENT)) {
2982 update_processed_blocks(rc, node);
2983 goto out;
2984 }
2985
2986 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2987 ret = reserve_metadata_space(trans, rc, node);
2988 if (ret)
2989 goto out;
2990 }
2991
2992 if (root) {
2993 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2994 BUG_ON(node->new_bytenr);
2995 BUG_ON(!list_empty(&node->list));
2996 btrfs_record_root_in_trans(trans, root);
2997 root = root->reloc_root;
2998 node->new_bytenr = root->node->start;
2999 node->root = root;
3000 list_add_tail(&node->list, &rc->backref_cache.changed);
3001 } else {
3002 path->lowest_level = node->level;
3003 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3004 btrfs_release_path(path);
3005 if (ret > 0)
3006 ret = 0;
3007 }
3008 if (!ret)
3009 update_processed_blocks(rc, node);
3010 } else {
3011 ret = do_relocation(trans, rc, node, key, path, 1);
3012 }
3013out:
3014 if (ret || node->level == 0 || node->cowonly)
3015 remove_backref_node(&rc->backref_cache, node);
3016 return ret;
3017}
3018
3019/*
3020 * relocate a list of blocks
3021 */
3022static noinline_for_stack
3023int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3024 struct reloc_control *rc, struct rb_root *blocks)
3025{
3026 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3027 struct backref_node *node;
3028 struct btrfs_path *path;
3029 struct tree_block *block;
3030 struct rb_node *rb_node;
3031 int ret;
3032 int err = 0;
3033
3034 path = btrfs_alloc_path();
3035 if (!path) {
3036 err = -ENOMEM;
3037 goto out_free_blocks;
3038 }
3039
3040 rb_node = rb_first(blocks);
3041 while (rb_node) {
3042 block = rb_entry(rb_node, struct tree_block, rb_node);
3043 if (!block->key_ready)
3044 readahead_tree_block(fs_info, block->bytenr);
3045 rb_node = rb_next(rb_node);
3046 }
3047
3048 rb_node = rb_first(blocks);
3049 while (rb_node) {
3050 block = rb_entry(rb_node, struct tree_block, rb_node);
3051 if (!block->key_ready) {
3052 err = get_tree_block_key(fs_info, block);
3053 if (err)
3054 goto out_free_path;
3055 }
3056 rb_node = rb_next(rb_node);
3057 }
3058
3059 rb_node = rb_first(blocks);
3060 while (rb_node) {
3061 block = rb_entry(rb_node, struct tree_block, rb_node);
3062
3063 node = build_backref_tree(rc, &block->key,
3064 block->level, block->bytenr);
3065 if (IS_ERR(node)) {
3066 err = PTR_ERR(node);
3067 goto out;
3068 }
3069
3070 ret = relocate_tree_block(trans, rc, node, &block->key,
3071 path);
3072 if (ret < 0) {
3073 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3074 err = ret;
3075 goto out;
3076 }
3077 rb_node = rb_next(rb_node);
3078 }
3079out:
3080 err = finish_pending_nodes(trans, rc, path, err);
3081
3082out_free_path:
3083 btrfs_free_path(path);
3084out_free_blocks:
3085 free_block_list(blocks);
3086 return err;
3087}
3088
3089static noinline_for_stack
3090int prealloc_file_extent_cluster(struct inode *inode,
3091 struct file_extent_cluster *cluster)
3092{
3093 u64 alloc_hint = 0;
3094 u64 start;
3095 u64 end;
3096 u64 offset = BTRFS_I(inode)->index_cnt;
3097 u64 num_bytes;
3098 int nr = 0;
3099 int ret = 0;
3100 u64 prealloc_start = cluster->start - offset;
3101 u64 prealloc_end = cluster->end - offset;
3102 u64 cur_offset;
3103 struct extent_changeset *data_reserved = NULL;
3104
3105 BUG_ON(cluster->start != cluster->boundary[0]);
3106 inode_lock(inode);
3107
3108 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3109 prealloc_end + 1 - prealloc_start);
3110 if (ret)
3111 goto out;
3112
3113 cur_offset = prealloc_start;
3114 while (nr < cluster->nr) {
3115 start = cluster->boundary[nr] - offset;
3116 if (nr + 1 < cluster->nr)
3117 end = cluster->boundary[nr + 1] - 1 - offset;
3118 else
3119 end = cluster->end - offset;
3120
3121 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3122 num_bytes = end + 1 - start;
3123 if (cur_offset < start)
3124 btrfs_free_reserved_data_space(inode, data_reserved,
3125 cur_offset, start - cur_offset);
3126 ret = btrfs_prealloc_file_range(inode, 0, start,
3127 num_bytes, num_bytes,
3128 end + 1, &alloc_hint);
3129 cur_offset = end + 1;
3130 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3131 if (ret)
3132 break;
3133 nr++;
3134 }
3135 if (cur_offset < prealloc_end)
3136 btrfs_free_reserved_data_space(inode, data_reserved,
3137 cur_offset, prealloc_end + 1 - cur_offset);
3138out:
3139 inode_unlock(inode);
3140 extent_changeset_free(data_reserved);
3141 return ret;
3142}
3143
3144static noinline_for_stack
3145int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3146 u64 block_start)
3147{
3148 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3149 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3150 struct extent_map *em;
3151 int ret = 0;
3152
3153 em = alloc_extent_map();
3154 if (!em)
3155 return -ENOMEM;
3156
3157 em->start = start;
3158 em->len = end + 1 - start;
3159 em->block_len = em->len;
3160 em->block_start = block_start;
3161 em->bdev = fs_info->fs_devices->latest_bdev;
3162 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3163
3164 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3165 while (1) {
3166 write_lock(&em_tree->lock);
3167 ret = add_extent_mapping(em_tree, em, 0);
3168 write_unlock(&em_tree->lock);
3169 if (ret != -EEXIST) {
3170 free_extent_map(em);
3171 break;
3172 }
3173 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3174 }
3175 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3176 return ret;
3177}
3178
3179static int relocate_file_extent_cluster(struct inode *inode,
3180 struct file_extent_cluster *cluster)
3181{
3182 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3183 u64 page_start;
3184 u64 page_end;
3185 u64 offset = BTRFS_I(inode)->index_cnt;
3186 unsigned long index;
3187 unsigned long last_index;
3188 struct page *page;
3189 struct file_ra_state *ra;
3190 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3191 int nr = 0;
3192 int ret = 0;
3193
3194 if (!cluster->nr)
3195 return 0;
3196
3197 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3198 if (!ra)
3199 return -ENOMEM;
3200
3201 ret = prealloc_file_extent_cluster(inode, cluster);
3202 if (ret)
3203 goto out;
3204
3205 file_ra_state_init(ra, inode->i_mapping);
3206
3207 ret = setup_extent_mapping(inode, cluster->start - offset,
3208 cluster->end - offset, cluster->start);
3209 if (ret)
3210 goto out;
3211
3212 index = (cluster->start - offset) >> PAGE_SHIFT;
3213 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3214 while (index <= last_index) {
3215 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3216 PAGE_SIZE);
3217 if (ret)
3218 goto out;
3219
3220 page = find_lock_page(inode->i_mapping, index);
3221 if (!page) {
3222 page_cache_sync_readahead(inode->i_mapping,
3223 ra, NULL, index,
3224 last_index + 1 - index);
3225 page = find_or_create_page(inode->i_mapping, index,
3226 mask);
3227 if (!page) {
3228 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3229 PAGE_SIZE, true);
3230 ret = -ENOMEM;
3231 goto out;
3232 }
3233 }
3234
3235 if (PageReadahead(page)) {
3236 page_cache_async_readahead(inode->i_mapping,
3237 ra, NULL, page, index,
3238 last_index + 1 - index);
3239 }
3240
3241 if (!PageUptodate(page)) {
3242 btrfs_readpage(NULL, page);
3243 lock_page(page);
3244 if (!PageUptodate(page)) {
3245 unlock_page(page);
3246 put_page(page);
3247 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3248 PAGE_SIZE, true);
3249 btrfs_delalloc_release_extents(BTRFS_I(inode),
3250 PAGE_SIZE, true);
3251 ret = -EIO;
3252 goto out;
3253 }
3254 }
3255
3256 page_start = page_offset(page);
3257 page_end = page_start + PAGE_SIZE - 1;
3258
3259 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3260
3261 set_page_extent_mapped(page);
3262
3263 if (nr < cluster->nr &&
3264 page_start + offset == cluster->boundary[nr]) {
3265 set_extent_bits(&BTRFS_I(inode)->io_tree,
3266 page_start, page_end,
3267 EXTENT_BOUNDARY);
3268 nr++;
3269 }
3270
3271 ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
3272 NULL, 0);
3273 if (ret) {
3274 unlock_page(page);
3275 put_page(page);
3276 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3277 PAGE_SIZE, true);
3278 btrfs_delalloc_release_extents(BTRFS_I(inode),
3279 PAGE_SIZE, true);
3280
3281 clear_extent_bits(&BTRFS_I(inode)->io_tree,
3282 page_start, page_end,
3283 EXTENT_LOCKED | EXTENT_BOUNDARY);
3284 goto out;
3285
3286 }
3287 set_page_dirty(page);
3288
3289 unlock_extent(&BTRFS_I(inode)->io_tree,
3290 page_start, page_end);
3291 unlock_page(page);
3292 put_page(page);
3293
3294 index++;
3295 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE,
3296 false);
3297 balance_dirty_pages_ratelimited(inode->i_mapping);
3298 btrfs_throttle(fs_info);
3299 }
3300 WARN_ON(nr != cluster->nr);
3301out:
3302 kfree(ra);
3303 return ret;
3304}
3305
3306static noinline_for_stack
3307int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3308 struct file_extent_cluster *cluster)
3309{
3310 int ret;
3311
3312 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3313 ret = relocate_file_extent_cluster(inode, cluster);
3314 if (ret)
3315 return ret;
3316 cluster->nr = 0;
3317 }
3318
3319 if (!cluster->nr)
3320 cluster->start = extent_key->objectid;
3321 else
3322 BUG_ON(cluster->nr >= MAX_EXTENTS);
3323 cluster->end = extent_key->objectid + extent_key->offset - 1;
3324 cluster->boundary[cluster->nr] = extent_key->objectid;
3325 cluster->nr++;
3326
3327 if (cluster->nr >= MAX_EXTENTS) {
3328 ret = relocate_file_extent_cluster(inode, cluster);
3329 if (ret)
3330 return ret;
3331 cluster->nr = 0;
3332 }
3333 return 0;
3334}
3335
3336#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3337static int get_ref_objectid_v0(struct reloc_control *rc,
3338 struct btrfs_path *path,
3339 struct btrfs_key *extent_key,
3340 u64 *ref_objectid, int *path_change)
3341{
3342 struct btrfs_key key;
3343 struct extent_buffer *leaf;
3344 struct btrfs_extent_ref_v0 *ref0;
3345 int ret;
3346 int slot;
3347
3348 leaf = path->nodes[0];
3349 slot = path->slots[0];
3350 while (1) {
3351 if (slot >= btrfs_header_nritems(leaf)) {
3352 ret = btrfs_next_leaf(rc->extent_root, path);
3353 if (ret < 0)
3354 return ret;
3355 BUG_ON(ret > 0);
3356 leaf = path->nodes[0];
3357 slot = path->slots[0];
3358 if (path_change)
3359 *path_change = 1;
3360 }
3361 btrfs_item_key_to_cpu(leaf, &key, slot);
3362 if (key.objectid != extent_key->objectid)
3363 return -ENOENT;
3364
3365 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3366 slot++;
3367 continue;
3368 }
3369 ref0 = btrfs_item_ptr(leaf, slot,
3370 struct btrfs_extent_ref_v0);
3371 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3372 break;
3373 }
3374 return 0;
3375}
3376#endif
3377
3378/*
3379 * helper to add a tree block to the list.
3380 * the major work is getting the generation and level of the block
3381 */
3382static int add_tree_block(struct reloc_control *rc,
3383 struct btrfs_key *extent_key,
3384 struct btrfs_path *path,
3385 struct rb_root *blocks)
3386{
3387 struct extent_buffer *eb;
3388 struct btrfs_extent_item *ei;
3389 struct btrfs_tree_block_info *bi;
3390 struct tree_block *block;
3391 struct rb_node *rb_node;
3392 u32 item_size;
3393 int level = -1;
3394 u64 generation;
3395
3396 eb = path->nodes[0];
3397 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3398
3399 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3400 item_size >= sizeof(*ei) + sizeof(*bi)) {
3401 ei = btrfs_item_ptr(eb, path->slots[0],
3402 struct btrfs_extent_item);
3403 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3404 bi = (struct btrfs_tree_block_info *)(ei + 1);
3405 level = btrfs_tree_block_level(eb, bi);
3406 } else {
3407 level = (int)extent_key->offset;
3408 }
3409 generation = btrfs_extent_generation(eb, ei);
3410 } else {
3411#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3412 u64 ref_owner;
3413 int ret;
3414
3415 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3416 ret = get_ref_objectid_v0(rc, path, extent_key,
3417 &ref_owner, NULL);
3418 if (ret < 0)
3419 return ret;
3420 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3421 level = (int)ref_owner;
3422 /* FIXME: get real generation */
3423 generation = 0;
3424#else
3425 BUG();
3426#endif
3427 }
3428
3429 btrfs_release_path(path);
3430
3431 BUG_ON(level == -1);
3432
3433 block = kmalloc(sizeof(*block), GFP_NOFS);
3434 if (!block)
3435 return -ENOMEM;
3436
3437 block->bytenr = extent_key->objectid;
3438 block->key.objectid = rc->extent_root->fs_info->nodesize;
3439 block->key.offset = generation;
3440 block->level = level;
3441 block->key_ready = 0;
3442
3443 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3444 if (rb_node)
3445 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3446
3447 return 0;
3448}
3449
3450/*
3451 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3452 */
3453static int __add_tree_block(struct reloc_control *rc,
3454 u64 bytenr, u32 blocksize,
3455 struct rb_root *blocks)
3456{
3457 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3458 struct btrfs_path *path;
3459 struct btrfs_key key;
3460 int ret;
3461 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3462
3463 if (tree_block_processed(bytenr, rc))
3464 return 0;
3465
3466 if (tree_search(blocks, bytenr))
3467 return 0;
3468
3469 path = btrfs_alloc_path();
3470 if (!path)
3471 return -ENOMEM;
3472again:
3473 key.objectid = bytenr;
3474 if (skinny) {
3475 key.type = BTRFS_METADATA_ITEM_KEY;
3476 key.offset = (u64)-1;
3477 } else {
3478 key.type = BTRFS_EXTENT_ITEM_KEY;
3479 key.offset = blocksize;
3480 }
3481
3482 path->search_commit_root = 1;
3483 path->skip_locking = 1;
3484 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3485 if (ret < 0)
3486 goto out;
3487
3488 if (ret > 0 && skinny) {
3489 if (path->slots[0]) {
3490 path->slots[0]--;
3491 btrfs_item_key_to_cpu(path->nodes[0], &key,
3492 path->slots[0]);
3493 if (key.objectid == bytenr &&
3494 (key.type == BTRFS_METADATA_ITEM_KEY ||
3495 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3496 key.offset == blocksize)))
3497 ret = 0;
3498 }
3499
3500 if (ret) {
3501 skinny = false;
3502 btrfs_release_path(path);
3503 goto again;
3504 }
3505 }
3506 if (ret) {
3507 ASSERT(ret == 1);
3508 btrfs_print_leaf(path->nodes[0]);
3509 btrfs_err(fs_info,
3510 "tree block extent item (%llu) is not found in extent tree",
3511 bytenr);
3512 WARN_ON(1);
3513 ret = -EINVAL;
3514 goto out;
3515 }
3516
3517 ret = add_tree_block(rc, &key, path, blocks);
3518out:
3519 btrfs_free_path(path);
3520 return ret;
3521}
3522
3523/*
3524 * helper to check if the block use full backrefs for pointers in it
3525 */
3526static int block_use_full_backref(struct reloc_control *rc,
3527 struct extent_buffer *eb)
3528{
3529 u64 flags;
3530 int ret;
3531
3532 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3533 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3534 return 1;
3535
3536 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3537 eb->start, btrfs_header_level(eb), 1,
3538 NULL, &flags);
3539 BUG_ON(ret);
3540
3541 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3542 ret = 1;
3543 else
3544 ret = 0;
3545 return ret;
3546}
3547
3548static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3549 struct btrfs_block_group_cache *block_group,
3550 struct inode *inode,
3551 u64 ino)
3552{
3553 struct btrfs_key key;
3554 struct btrfs_root *root = fs_info->tree_root;
3555 struct btrfs_trans_handle *trans;
3556 int ret = 0;
3557
3558 if (inode)
3559 goto truncate;
3560
3561 key.objectid = ino;
3562 key.type = BTRFS_INODE_ITEM_KEY;
3563 key.offset = 0;
3564
3565 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3566 if (IS_ERR(inode) || is_bad_inode(inode)) {
3567 if (!IS_ERR(inode))
3568 iput(inode);
3569 return -ENOENT;
3570 }
3571
3572truncate:
3573 ret = btrfs_check_trunc_cache_free_space(fs_info,
3574 &fs_info->global_block_rsv);
3575 if (ret)
3576 goto out;
3577
3578 trans = btrfs_join_transaction(root);
3579 if (IS_ERR(trans)) {
3580 ret = PTR_ERR(trans);
3581 goto out;
3582 }
3583
3584 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3585
3586 btrfs_end_transaction(trans);
3587 btrfs_btree_balance_dirty(fs_info);
3588out:
3589 iput(inode);
3590 return ret;
3591}
3592
3593/*
3594 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3595 * this function scans fs tree to find blocks reference the data extent
3596 */
3597static int find_data_references(struct reloc_control *rc,
3598 struct btrfs_key *extent_key,
3599 struct extent_buffer *leaf,
3600 struct btrfs_extent_data_ref *ref,
3601 struct rb_root *blocks)
3602{
3603 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3604 struct btrfs_path *path;
3605 struct tree_block *block;
3606 struct btrfs_root *root;
3607 struct btrfs_file_extent_item *fi;
3608 struct rb_node *rb_node;
3609 struct btrfs_key key;
3610 u64 ref_root;
3611 u64 ref_objectid;
3612 u64 ref_offset;
3613 u32 ref_count;
3614 u32 nritems;
3615 int err = 0;
3616 int added = 0;
3617 int counted;
3618 int ret;
3619
3620 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3621 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3622 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3623 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3624
3625 /*
3626 * This is an extent belonging to the free space cache, lets just delete
3627 * it and redo the search.
3628 */
3629 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3630 ret = delete_block_group_cache(fs_info, rc->block_group,
3631 NULL, ref_objectid);
3632 if (ret != -ENOENT)
3633 return ret;
3634 ret = 0;
3635 }
3636
3637 path = btrfs_alloc_path();
3638 if (!path)
3639 return -ENOMEM;
3640 path->reada = READA_FORWARD;
3641
3642 root = read_fs_root(fs_info, ref_root);
3643 if (IS_ERR(root)) {
3644 err = PTR_ERR(root);
3645 goto out;
3646 }
3647
3648 key.objectid = ref_objectid;
3649 key.type = BTRFS_EXTENT_DATA_KEY;
3650 if (ref_offset > ((u64)-1 << 32))
3651 key.offset = 0;
3652 else
3653 key.offset = ref_offset;
3654
3655 path->search_commit_root = 1;
3656 path->skip_locking = 1;
3657 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3658 if (ret < 0) {
3659 err = ret;
3660 goto out;
3661 }
3662
3663 leaf = path->nodes[0];
3664 nritems = btrfs_header_nritems(leaf);
3665 /*
3666 * the references in tree blocks that use full backrefs
3667 * are not counted in
3668 */
3669 if (block_use_full_backref(rc, leaf))
3670 counted = 0;
3671 else
3672 counted = 1;
3673 rb_node = tree_search(blocks, leaf->start);
3674 if (rb_node) {
3675 if (counted)
3676 added = 1;
3677 else
3678 path->slots[0] = nritems;
3679 }
3680
3681 while (ref_count > 0) {
3682 while (path->slots[0] >= nritems) {
3683 ret = btrfs_next_leaf(root, path);
3684 if (ret < 0) {
3685 err = ret;
3686 goto out;
3687 }
3688 if (WARN_ON(ret > 0))
3689 goto out;
3690
3691 leaf = path->nodes[0];
3692 nritems = btrfs_header_nritems(leaf);
3693 added = 0;
3694
3695 if (block_use_full_backref(rc, leaf))
3696 counted = 0;
3697 else
3698 counted = 1;
3699 rb_node = tree_search(blocks, leaf->start);
3700 if (rb_node) {
3701 if (counted)
3702 added = 1;
3703 else
3704 path->slots[0] = nritems;
3705 }
3706 }
3707
3708 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3709 if (WARN_ON(key.objectid != ref_objectid ||
3710 key.type != BTRFS_EXTENT_DATA_KEY))
3711 break;
3712
3713 fi = btrfs_item_ptr(leaf, path->slots[0],
3714 struct btrfs_file_extent_item);
3715
3716 if (btrfs_file_extent_type(leaf, fi) ==
3717 BTRFS_FILE_EXTENT_INLINE)
3718 goto next;
3719
3720 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3721 extent_key->objectid)
3722 goto next;
3723
3724 key.offset -= btrfs_file_extent_offset(leaf, fi);
3725 if (key.offset != ref_offset)
3726 goto next;
3727
3728 if (counted)
3729 ref_count--;
3730 if (added)
3731 goto next;
3732
3733 if (!tree_block_processed(leaf->start, rc)) {
3734 block = kmalloc(sizeof(*block), GFP_NOFS);
3735 if (!block) {
3736 err = -ENOMEM;
3737 break;
3738 }
3739 block->bytenr = leaf->start;
3740 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3741 block->level = 0;
3742 block->key_ready = 1;
3743 rb_node = tree_insert(blocks, block->bytenr,
3744 &block->rb_node);
3745 if (rb_node)
3746 backref_tree_panic(rb_node, -EEXIST,
3747 block->bytenr);
3748 }
3749 if (counted)
3750 added = 1;
3751 else
3752 path->slots[0] = nritems;
3753next:
3754 path->slots[0]++;
3755
3756 }
3757out:
3758 btrfs_free_path(path);
3759 return err;
3760}
3761
3762/*
3763 * helper to find all tree blocks that reference a given data extent
3764 */
3765static noinline_for_stack
3766int add_data_references(struct reloc_control *rc,
3767 struct btrfs_key *extent_key,
3768 struct btrfs_path *path,
3769 struct rb_root *blocks)
3770{
3771 struct btrfs_key key;
3772 struct extent_buffer *eb;
3773 struct btrfs_extent_data_ref *dref;
3774 struct btrfs_extent_inline_ref *iref;
3775 unsigned long ptr;
3776 unsigned long end;
3777 u32 blocksize = rc->extent_root->fs_info->nodesize;
3778 int ret = 0;
3779 int err = 0;
3780
3781 eb = path->nodes[0];
3782 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3783 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3784#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3785 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3786 ptr = end;
3787 else
3788#endif
3789 ptr += sizeof(struct btrfs_extent_item);
3790
3791 while (ptr < end) {
3792 iref = (struct btrfs_extent_inline_ref *)ptr;
3793 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3794 BTRFS_REF_TYPE_DATA);
3795 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3796 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3797 ret = __add_tree_block(rc, key.offset, blocksize,
3798 blocks);
3799 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3800 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3801 ret = find_data_references(rc, extent_key,
3802 eb, dref, blocks);
3803 } else {
3804 ret = -EINVAL;
3805 btrfs_err(rc->extent_root->fs_info,
3806 "extent %llu slot %d has an invalid inline ref type",
3807 eb->start, path->slots[0]);
3808 }
3809 if (ret) {
3810 err = ret;
3811 goto out;
3812 }
3813 ptr += btrfs_extent_inline_ref_size(key.type);
3814 }
3815 WARN_ON(ptr > end);
3816
3817 while (1) {
3818 cond_resched();
3819 eb = path->nodes[0];
3820 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3821 ret = btrfs_next_leaf(rc->extent_root, path);
3822 if (ret < 0) {
3823 err = ret;
3824 break;
3825 }
3826 if (ret > 0)
3827 break;
3828 eb = path->nodes[0];
3829 }
3830
3831 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3832 if (key.objectid != extent_key->objectid)
3833 break;
3834
3835#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3836 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3837 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3838#else
3839 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3840 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3841#endif
3842 ret = __add_tree_block(rc, key.offset, blocksize,
3843 blocks);
3844 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3845 dref = btrfs_item_ptr(eb, path->slots[0],
3846 struct btrfs_extent_data_ref);
3847 ret = find_data_references(rc, extent_key,
3848 eb, dref, blocks);
3849 } else {
3850 ret = 0;
3851 }
3852 if (ret) {
3853 err = ret;
3854 break;
3855 }
3856 path->slots[0]++;
3857 }
3858out:
3859 btrfs_release_path(path);
3860 if (err)
3861 free_block_list(blocks);
3862 return err;
3863}
3864
3865/*
3866 * helper to find next unprocessed extent
3867 */
3868static noinline_for_stack
3869int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3870 struct btrfs_key *extent_key)
3871{
3872 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3873 struct btrfs_key key;
3874 struct extent_buffer *leaf;
3875 u64 start, end, last;
3876 int ret;
3877
3878 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3879 while (1) {
3880 cond_resched();
3881 if (rc->search_start >= last) {
3882 ret = 1;
3883 break;
3884 }
3885
3886 key.objectid = rc->search_start;
3887 key.type = BTRFS_EXTENT_ITEM_KEY;
3888 key.offset = 0;
3889
3890 path->search_commit_root = 1;
3891 path->skip_locking = 1;
3892 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3893 0, 0);
3894 if (ret < 0)
3895 break;
3896next:
3897 leaf = path->nodes[0];
3898 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3899 ret = btrfs_next_leaf(rc->extent_root, path);
3900 if (ret != 0)
3901 break;
3902 leaf = path->nodes[0];
3903 }
3904
3905 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3906 if (key.objectid >= last) {
3907 ret = 1;
3908 break;
3909 }
3910
3911 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3912 key.type != BTRFS_METADATA_ITEM_KEY) {
3913 path->slots[0]++;
3914 goto next;
3915 }
3916
3917 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3918 key.objectid + key.offset <= rc->search_start) {
3919 path->slots[0]++;
3920 goto next;
3921 }
3922
3923 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3924 key.objectid + fs_info->nodesize <=
3925 rc->search_start) {
3926 path->slots[0]++;
3927 goto next;
3928 }
3929
3930 ret = find_first_extent_bit(&rc->processed_blocks,
3931 key.objectid, &start, &end,
3932 EXTENT_DIRTY, NULL);
3933
3934 if (ret == 0 && start <= key.objectid) {
3935 btrfs_release_path(path);
3936 rc->search_start = end + 1;
3937 } else {
3938 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3939 rc->search_start = key.objectid + key.offset;
3940 else
3941 rc->search_start = key.objectid +
3942 fs_info->nodesize;
3943 memcpy(extent_key, &key, sizeof(key));
3944 return 0;
3945 }
3946 }
3947 btrfs_release_path(path);
3948 return ret;
3949}
3950
3951static void set_reloc_control(struct reloc_control *rc)
3952{
3953 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3954
3955 mutex_lock(&fs_info->reloc_mutex);
3956 fs_info->reloc_ctl = rc;
3957 mutex_unlock(&fs_info->reloc_mutex);
3958}
3959
3960static void unset_reloc_control(struct reloc_control *rc)
3961{
3962 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3963
3964 mutex_lock(&fs_info->reloc_mutex);
3965 fs_info->reloc_ctl = NULL;
3966 mutex_unlock(&fs_info->reloc_mutex);
3967}
3968
3969static int check_extent_flags(u64 flags)
3970{
3971 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3972 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3973 return 1;
3974 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3975 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3976 return 1;
3977 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3978 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3979 return 1;
3980 return 0;
3981}
3982
3983static noinline_for_stack
3984int prepare_to_relocate(struct reloc_control *rc)
3985{
3986 struct btrfs_trans_handle *trans;
3987 int ret;
3988
3989 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3990 BTRFS_BLOCK_RSV_TEMP);
3991 if (!rc->block_rsv)
3992 return -ENOMEM;
3993
3994 memset(&rc->cluster, 0, sizeof(rc->cluster));
3995 rc->search_start = rc->block_group->key.objectid;
3996 rc->extents_found = 0;
3997 rc->nodes_relocated = 0;
3998 rc->merging_rsv_size = 0;
3999 rc->reserved_bytes = 0;
4000 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
4001 RELOCATION_RESERVED_NODES;
4002 ret = btrfs_block_rsv_refill(rc->extent_root,
4003 rc->block_rsv, rc->block_rsv->size,
4004 BTRFS_RESERVE_FLUSH_ALL);
4005 if (ret)
4006 return ret;
4007
4008 rc->create_reloc_tree = 1;
4009 set_reloc_control(rc);
4010
4011 trans = btrfs_join_transaction(rc->extent_root);
4012 if (IS_ERR(trans)) {
4013 unset_reloc_control(rc);
4014 /*
4015 * extent tree is not a ref_cow tree and has no reloc_root to
4016 * cleanup. And callers are responsible to free the above
4017 * block rsv.
4018 */
4019 return PTR_ERR(trans);
4020 }
4021 btrfs_commit_transaction(trans);
4022 return 0;
4023}
4024
4025static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4026{
4027 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
4028 struct rb_root blocks = RB_ROOT;
4029 struct btrfs_key key;
4030 struct btrfs_trans_handle *trans = NULL;
4031 struct btrfs_path *path;
4032 struct btrfs_extent_item *ei;
4033 u64 flags;
4034 u32 item_size;
4035 int ret;
4036 int err = 0;
4037 int progress = 0;
4038
4039 path = btrfs_alloc_path();
4040 if (!path)
4041 return -ENOMEM;
4042 path->reada = READA_FORWARD;
4043
4044 ret = prepare_to_relocate(rc);
4045 if (ret) {
4046 err = ret;
4047 goto out_free;
4048 }
4049
4050 while (1) {
4051 rc->reserved_bytes = 0;
4052 ret = btrfs_block_rsv_refill(rc->extent_root,
4053 rc->block_rsv, rc->block_rsv->size,
4054 BTRFS_RESERVE_FLUSH_ALL);
4055 if (ret) {
4056 err = ret;
4057 break;
4058 }
4059 progress++;
4060 trans = btrfs_start_transaction(rc->extent_root, 0);
4061 if (IS_ERR(trans)) {
4062 err = PTR_ERR(trans);
4063 trans = NULL;
4064 break;
4065 }
4066restart:
4067 if (update_backref_cache(trans, &rc->backref_cache)) {
4068 btrfs_end_transaction(trans);
4069 continue;
4070 }
4071
4072 ret = find_next_extent(rc, path, &key);
4073 if (ret < 0)
4074 err = ret;
4075 if (ret != 0)
4076 break;
4077
4078 rc->extents_found++;
4079
4080 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4081 struct btrfs_extent_item);
4082 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4083 if (item_size >= sizeof(*ei)) {
4084 flags = btrfs_extent_flags(path->nodes[0], ei);
4085 ret = check_extent_flags(flags);
4086 BUG_ON(ret);
4087
4088 } else {
4089#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4090 u64 ref_owner;
4091 int path_change = 0;
4092
4093 BUG_ON(item_size !=
4094 sizeof(struct btrfs_extent_item_v0));
4095 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
4096 &path_change);
4097 if (ret < 0) {
4098 err = ret;
4099 break;
4100 }
4101 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
4102 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
4103 else
4104 flags = BTRFS_EXTENT_FLAG_DATA;
4105
4106 if (path_change) {
4107 btrfs_release_path(path);
4108
4109 path->search_commit_root = 1;
4110 path->skip_locking = 1;
4111 ret = btrfs_search_slot(NULL, rc->extent_root,
4112 &key, path, 0, 0);
4113 if (ret < 0) {
4114 err = ret;
4115 break;
4116 }
4117 BUG_ON(ret > 0);
4118 }
4119#else
4120 BUG();
4121#endif
4122 }
4123
4124 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4125 ret = add_tree_block(rc, &key, path, &blocks);
4126 } else if (rc->stage == UPDATE_DATA_PTRS &&
4127 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4128 ret = add_data_references(rc, &key, path, &blocks);
4129 } else {
4130 btrfs_release_path(path);
4131 ret = 0;
4132 }
4133 if (ret < 0) {
4134 err = ret;
4135 break;
4136 }
4137
4138 if (!RB_EMPTY_ROOT(&blocks)) {
4139 ret = relocate_tree_blocks(trans, rc, &blocks);
4140 if (ret < 0) {
4141 /*
4142 * if we fail to relocate tree blocks, force to update
4143 * backref cache when committing transaction.
4144 */
4145 rc->backref_cache.last_trans = trans->transid - 1;
4146
4147 if (ret != -EAGAIN) {
4148 err = ret;
4149 break;
4150 }
4151 rc->extents_found--;
4152 rc->search_start = key.objectid;
4153 }
4154 }
4155
4156 btrfs_end_transaction_throttle(trans);
4157 btrfs_btree_balance_dirty(fs_info);
4158 trans = NULL;
4159
4160 if (rc->stage == MOVE_DATA_EXTENTS &&
4161 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4162 rc->found_file_extent = 1;
4163 ret = relocate_data_extent(rc->data_inode,
4164 &key, &rc->cluster);
4165 if (ret < 0) {
4166 err = ret;
4167 break;
4168 }
4169 }
4170 }
4171 if (trans && progress && err == -ENOSPC) {
4172 ret = btrfs_force_chunk_alloc(trans, fs_info,
4173 rc->block_group->flags);
4174 if (ret == 1) {
4175 err = 0;
4176 progress = 0;
4177 goto restart;
4178 }
4179 }
4180
4181 btrfs_release_path(path);
4182 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4183
4184 if (trans) {
4185 btrfs_end_transaction_throttle(trans);
4186 btrfs_btree_balance_dirty(fs_info);
4187 }
4188
4189 if (!err) {
4190 ret = relocate_file_extent_cluster(rc->data_inode,
4191 &rc->cluster);
4192 if (ret < 0)
4193 err = ret;
4194 }
4195
4196 rc->create_reloc_tree = 0;
4197 set_reloc_control(rc);
4198
4199 backref_cache_cleanup(&rc->backref_cache);
4200 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4201
4202 err = prepare_to_merge(rc, err);
4203
4204 merge_reloc_roots(rc);
4205
4206 rc->merge_reloc_tree = 0;
4207 unset_reloc_control(rc);
4208 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4209
4210 /* get rid of pinned extents */
4211 trans = btrfs_join_transaction(rc->extent_root);
4212 if (IS_ERR(trans)) {
4213 err = PTR_ERR(trans);
4214 goto out_free;
4215 }
4216 btrfs_commit_transaction(trans);
4217out_free:
4218 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4219 btrfs_free_path(path);
4220 return err;
4221}
4222
4223static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4224 struct btrfs_root *root, u64 objectid)
4225{
4226 struct btrfs_path *path;
4227 struct btrfs_inode_item *item;
4228 struct extent_buffer *leaf;
4229 int ret;
4230
4231 path = btrfs_alloc_path();
4232 if (!path)
4233 return -ENOMEM;
4234
4235 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4236 if (ret)
4237 goto out;
4238
4239 leaf = path->nodes[0];
4240 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4241 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4242 btrfs_set_inode_generation(leaf, item, 1);
4243 btrfs_set_inode_size(leaf, item, 0);
4244 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4245 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4246 BTRFS_INODE_PREALLOC);
4247 btrfs_mark_buffer_dirty(leaf);
4248out:
4249 btrfs_free_path(path);
4250 return ret;
4251}
4252
4253/*
4254 * helper to create inode for data relocation.
4255 * the inode is in data relocation tree and its link count is 0
4256 */
4257static noinline_for_stack
4258struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4259 struct btrfs_block_group_cache *group)
4260{
4261 struct inode *inode = NULL;
4262 struct btrfs_trans_handle *trans;
4263 struct btrfs_root *root;
4264 struct btrfs_key key;
4265 u64 objectid;
4266 int err = 0;
4267
4268 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4269 if (IS_ERR(root))
4270 return ERR_CAST(root);
4271
4272 trans = btrfs_start_transaction(root, 6);
4273 if (IS_ERR(trans))
4274 return ERR_CAST(trans);
4275
4276 err = btrfs_find_free_objectid(root, &objectid);
4277 if (err)
4278 goto out;
4279
4280 err = __insert_orphan_inode(trans, root, objectid);
4281 BUG_ON(err);
4282
4283 key.objectid = objectid;
4284 key.type = BTRFS_INODE_ITEM_KEY;
4285 key.offset = 0;
4286 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4287 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4288 BTRFS_I(inode)->index_cnt = group->key.objectid;
4289
4290 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4291out:
4292 btrfs_end_transaction(trans);
4293 btrfs_btree_balance_dirty(fs_info);
4294 if (err) {
4295 if (inode)
4296 iput(inode);
4297 inode = ERR_PTR(err);
4298 }
4299 return inode;
4300}
4301
4302static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4303{
4304 struct reloc_control *rc;
4305
4306 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4307 if (!rc)
4308 return NULL;
4309
4310 INIT_LIST_HEAD(&rc->reloc_roots);
4311 backref_cache_init(&rc->backref_cache);
4312 mapping_tree_init(&rc->reloc_root_tree);
4313 extent_io_tree_init(&rc->processed_blocks, NULL);
4314 return rc;
4315}
4316
4317/*
4318 * Print the block group being relocated
4319 */
4320static void describe_relocation(struct btrfs_fs_info *fs_info,
4321 struct btrfs_block_group_cache *block_group)
4322{
4323 char buf[128]; /* prefixed by a '|' that'll be dropped */
4324 u64 flags = block_group->flags;
4325
4326 /* Shouldn't happen */
4327 if (!flags) {
4328 strcpy(buf, "|NONE");
4329 } else {
4330 char *bp = buf;
4331
4332#define DESCRIBE_FLAG(f, d) \
4333 if (flags & BTRFS_BLOCK_GROUP_##f) { \
4334 bp += snprintf(bp, buf - bp + sizeof(buf), "|%s", d); \
4335 flags &= ~BTRFS_BLOCK_GROUP_##f; \
4336 }
4337 DESCRIBE_FLAG(DATA, "data");
4338 DESCRIBE_FLAG(SYSTEM, "system");
4339 DESCRIBE_FLAG(METADATA, "metadata");
4340 DESCRIBE_FLAG(RAID0, "raid0");
4341 DESCRIBE_FLAG(RAID1, "raid1");
4342 DESCRIBE_FLAG(DUP, "dup");
4343 DESCRIBE_FLAG(RAID10, "raid10");
4344 DESCRIBE_FLAG(RAID5, "raid5");
4345 DESCRIBE_FLAG(RAID6, "raid6");
4346 if (flags)
4347 snprintf(buf, buf - bp + sizeof(buf), "|0x%llx", flags);
4348#undef DESCRIBE_FLAG
4349 }
4350
4351 btrfs_info(fs_info,
4352 "relocating block group %llu flags %s",
4353 block_group->key.objectid, buf + 1);
4354}
4355
4356/*
4357 * function to relocate all extents in a block group.
4358 */
4359int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4360{
4361 struct btrfs_root *extent_root = fs_info->extent_root;
4362 struct reloc_control *rc;
4363 struct inode *inode;
4364 struct btrfs_path *path;
4365 int ret;
4366 int rw = 0;
4367 int err = 0;
4368
4369 rc = alloc_reloc_control(fs_info);
4370 if (!rc)
4371 return -ENOMEM;
4372
4373 rc->extent_root = extent_root;
4374
4375 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4376 BUG_ON(!rc->block_group);
4377
4378 ret = btrfs_inc_block_group_ro(fs_info, rc->block_group);
4379 if (ret) {
4380 err = ret;
4381 goto out;
4382 }
4383 rw = 1;
4384
4385 path = btrfs_alloc_path();
4386 if (!path) {
4387 err = -ENOMEM;
4388 goto out;
4389 }
4390
4391 inode = lookup_free_space_inode(fs_info, rc->block_group, path);
4392 btrfs_free_path(path);
4393
4394 if (!IS_ERR(inode))
4395 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4396 else
4397 ret = PTR_ERR(inode);
4398
4399 if (ret && ret != -ENOENT) {
4400 err = ret;
4401 goto out;
4402 }
4403
4404 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4405 if (IS_ERR(rc->data_inode)) {
4406 err = PTR_ERR(rc->data_inode);
4407 rc->data_inode = NULL;
4408 goto out;
4409 }
4410
4411 describe_relocation(fs_info, rc->block_group);
4412
4413 btrfs_wait_block_group_reservations(rc->block_group);
4414 btrfs_wait_nocow_writers(rc->block_group);
4415 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4416 rc->block_group->key.objectid,
4417 rc->block_group->key.offset);
4418
4419 while (1) {
4420 mutex_lock(&fs_info->cleaner_mutex);
4421 ret = relocate_block_group(rc);
4422 mutex_unlock(&fs_info->cleaner_mutex);
4423 if (ret < 0) {
4424 err = ret;
4425 goto out;
4426 }
4427
4428 if (rc->extents_found == 0)
4429 break;
4430
4431 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4432
4433 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4434 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4435 (u64)-1);
4436 if (ret) {
4437 err = ret;
4438 goto out;
4439 }
4440 invalidate_mapping_pages(rc->data_inode->i_mapping,
4441 0, -1);
4442 rc->stage = UPDATE_DATA_PTRS;
4443 }
4444 }
4445
4446 WARN_ON(rc->block_group->pinned > 0);
4447 WARN_ON(rc->block_group->reserved > 0);
4448 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4449out:
4450 if (err && rw)
4451 btrfs_dec_block_group_ro(rc->block_group);
4452 iput(rc->data_inode);
4453 btrfs_put_block_group(rc->block_group);
4454 kfree(rc);
4455 return err;
4456}
4457
4458static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4459{
4460 struct btrfs_fs_info *fs_info = root->fs_info;
4461 struct btrfs_trans_handle *trans;
4462 int ret, err;
4463
4464 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4465 if (IS_ERR(trans))
4466 return PTR_ERR(trans);
4467
4468 memset(&root->root_item.drop_progress, 0,
4469 sizeof(root->root_item.drop_progress));
4470 root->root_item.drop_level = 0;
4471 btrfs_set_root_refs(&root->root_item, 0);
4472 ret = btrfs_update_root(trans, fs_info->tree_root,
4473 &root->root_key, &root->root_item);
4474
4475 err = btrfs_end_transaction(trans);
4476 if (err)
4477 return err;
4478 return ret;
4479}
4480
4481/*
4482 * recover relocation interrupted by system crash.
4483 *
4484 * this function resumes merging reloc trees with corresponding fs trees.
4485 * this is important for keeping the sharing of tree blocks
4486 */
4487int btrfs_recover_relocation(struct btrfs_root *root)
4488{
4489 struct btrfs_fs_info *fs_info = root->fs_info;
4490 LIST_HEAD(reloc_roots);
4491 struct btrfs_key key;
4492 struct btrfs_root *fs_root;
4493 struct btrfs_root *reloc_root;
4494 struct btrfs_path *path;
4495 struct extent_buffer *leaf;
4496 struct reloc_control *rc = NULL;
4497 struct btrfs_trans_handle *trans;
4498 int ret;
4499 int err = 0;
4500
4501 path = btrfs_alloc_path();
4502 if (!path)
4503 return -ENOMEM;
4504 path->reada = READA_BACK;
4505
4506 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4507 key.type = BTRFS_ROOT_ITEM_KEY;
4508 key.offset = (u64)-1;
4509
4510 while (1) {
4511 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4512 path, 0, 0);
4513 if (ret < 0) {
4514 err = ret;
4515 goto out;
4516 }
4517 if (ret > 0) {
4518 if (path->slots[0] == 0)
4519 break;
4520 path->slots[0]--;
4521 }
4522 leaf = path->nodes[0];
4523 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4524 btrfs_release_path(path);
4525
4526 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4527 key.type != BTRFS_ROOT_ITEM_KEY)
4528 break;
4529
4530 reloc_root = btrfs_read_fs_root(root, &key);
4531 if (IS_ERR(reloc_root)) {
4532 err = PTR_ERR(reloc_root);
4533 goto out;
4534 }
4535
4536 list_add(&reloc_root->root_list, &reloc_roots);
4537
4538 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4539 fs_root = read_fs_root(fs_info,
4540 reloc_root->root_key.offset);
4541 if (IS_ERR(fs_root)) {
4542 ret = PTR_ERR(fs_root);
4543 if (ret != -ENOENT) {
4544 err = ret;
4545 goto out;
4546 }
4547 ret = mark_garbage_root(reloc_root);
4548 if (ret < 0) {
4549 err = ret;
4550 goto out;
4551 }
4552 }
4553 }
4554
4555 if (key.offset == 0)
4556 break;
4557
4558 key.offset--;
4559 }
4560 btrfs_release_path(path);
4561
4562 if (list_empty(&reloc_roots))
4563 goto out;
4564
4565 rc = alloc_reloc_control(fs_info);
4566 if (!rc) {
4567 err = -ENOMEM;
4568 goto out;
4569 }
4570
4571 rc->extent_root = fs_info->extent_root;
4572
4573 set_reloc_control(rc);
4574
4575 trans = btrfs_join_transaction(rc->extent_root);
4576 if (IS_ERR(trans)) {
4577 unset_reloc_control(rc);
4578 err = PTR_ERR(trans);
4579 goto out_free;
4580 }
4581
4582 rc->merge_reloc_tree = 1;
4583
4584 while (!list_empty(&reloc_roots)) {
4585 reloc_root = list_entry(reloc_roots.next,
4586 struct btrfs_root, root_list);
4587 list_del(&reloc_root->root_list);
4588
4589 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4590 list_add_tail(&reloc_root->root_list,
4591 &rc->reloc_roots);
4592 continue;
4593 }
4594
4595 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4596 if (IS_ERR(fs_root)) {
4597 err = PTR_ERR(fs_root);
4598 goto out_free;
4599 }
4600
4601 err = __add_reloc_root(reloc_root);
4602 BUG_ON(err < 0); /* -ENOMEM or logic error */
4603 fs_root->reloc_root = reloc_root;
4604 }
4605
4606 err = btrfs_commit_transaction(trans);
4607 if (err)
4608 goto out_free;
4609
4610 merge_reloc_roots(rc);
4611
4612 unset_reloc_control(rc);
4613
4614 trans = btrfs_join_transaction(rc->extent_root);
4615 if (IS_ERR(trans)) {
4616 err = PTR_ERR(trans);
4617 goto out_free;
4618 }
4619 err = btrfs_commit_transaction(trans);
4620out_free:
4621 kfree(rc);
4622out:
4623 if (!list_empty(&reloc_roots))
4624 free_reloc_roots(&reloc_roots);
4625
4626 btrfs_free_path(path);
4627
4628 if (err == 0) {
4629 /* cleanup orphan inode in data relocation tree */
4630 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4631 if (IS_ERR(fs_root))
4632 err = PTR_ERR(fs_root);
4633 else
4634 err = btrfs_orphan_cleanup(fs_root);
4635 }
4636 return err;
4637}
4638
4639/*
4640 * helper to add ordered checksum for data relocation.
4641 *
4642 * cloning checksum properly handles the nodatasum extents.
4643 * it also saves CPU time to re-calculate the checksum.
4644 */
4645int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4646{
4647 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4648 struct btrfs_ordered_sum *sums;
4649 struct btrfs_ordered_extent *ordered;
4650 int ret;
4651 u64 disk_bytenr;
4652 u64 new_bytenr;
4653 LIST_HEAD(list);
4654
4655 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4656 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4657
4658 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4659 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4660 disk_bytenr + len - 1, &list, 0);
4661 if (ret)
4662 goto out;
4663
4664 while (!list_empty(&list)) {
4665 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4666 list_del_init(&sums->list);
4667
4668 /*
4669 * We need to offset the new_bytenr based on where the csum is.
4670 * We need to do this because we will read in entire prealloc
4671 * extents but we may have written to say the middle of the
4672 * prealloc extent, so we need to make sure the csum goes with
4673 * the right disk offset.
4674 *
4675 * We can do this because the data reloc inode refers strictly
4676 * to the on disk bytes, so we don't have to worry about
4677 * disk_len vs real len like with real inodes since it's all
4678 * disk length.
4679 */
4680 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4681 sums->bytenr = new_bytenr;
4682
4683 btrfs_add_ordered_sum(inode, ordered, sums);
4684 }
4685out:
4686 btrfs_put_ordered_extent(ordered);
4687 return ret;
4688}
4689
4690int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4691 struct btrfs_root *root, struct extent_buffer *buf,
4692 struct extent_buffer *cow)
4693{
4694 struct btrfs_fs_info *fs_info = root->fs_info;
4695 struct reloc_control *rc;
4696 struct backref_node *node;
4697 int first_cow = 0;
4698 int level;
4699 int ret = 0;
4700
4701 rc = fs_info->reloc_ctl;
4702 if (!rc)
4703 return 0;
4704
4705 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4706 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4707
4708 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4709 if (buf == root->node)
4710 __update_reloc_root(root, cow->start);
4711 }
4712
4713 level = btrfs_header_level(buf);
4714 if (btrfs_header_generation(buf) <=
4715 btrfs_root_last_snapshot(&root->root_item))
4716 first_cow = 1;
4717
4718 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4719 rc->create_reloc_tree) {
4720 WARN_ON(!first_cow && level == 0);
4721
4722 node = rc->backref_cache.path[level];
4723 BUG_ON(node->bytenr != buf->start &&
4724 node->new_bytenr != buf->start);
4725
4726 drop_node_buffer(node);
4727 extent_buffer_get(cow);
4728 node->eb = cow;
4729 node->new_bytenr = cow->start;
4730
4731 if (!node->pending) {
4732 list_move_tail(&node->list,
4733 &rc->backref_cache.pending[level]);
4734 node->pending = 1;
4735 }
4736
4737 if (first_cow)
4738 __mark_block_processed(rc, node);
4739
4740 if (first_cow && level > 0)
4741 rc->nodes_relocated += buf->len;
4742 }
4743
4744 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4745 ret = replace_file_extents(trans, rc, root, cow);
4746 return ret;
4747}
4748
4749/*
4750 * called before creating snapshot. it calculates metadata reservation
4751 * required for relocating tree blocks in the snapshot
4752 */
4753void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4754 u64 *bytes_to_reserve)
4755{
4756 struct btrfs_root *root;
4757 struct reloc_control *rc;
4758
4759 root = pending->root;
4760 if (!root->reloc_root)
4761 return;
4762
4763 rc = root->fs_info->reloc_ctl;
4764 if (!rc->merge_reloc_tree)
4765 return;
4766
4767 root = root->reloc_root;
4768 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4769 /*
4770 * relocation is in the stage of merging trees. the space
4771 * used by merging a reloc tree is twice the size of
4772 * relocated tree nodes in the worst case. half for cowing
4773 * the reloc tree, half for cowing the fs tree. the space
4774 * used by cowing the reloc tree will be freed after the
4775 * tree is dropped. if we create snapshot, cowing the fs
4776 * tree may use more space than it frees. so we need
4777 * reserve extra space.
4778 */
4779 *bytes_to_reserve += rc->nodes_relocated;
4780}
4781
4782/*
4783 * called after snapshot is created. migrate block reservation
4784 * and create reloc root for the newly created snapshot
4785 */
4786int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4787 struct btrfs_pending_snapshot *pending)
4788{
4789 struct btrfs_root *root = pending->root;
4790 struct btrfs_root *reloc_root;
4791 struct btrfs_root *new_root;
4792 struct reloc_control *rc;
4793 int ret;
4794
4795 if (!root->reloc_root)
4796 return 0;
4797
4798 rc = root->fs_info->reloc_ctl;
4799 rc->merging_rsv_size += rc->nodes_relocated;
4800
4801 if (rc->merge_reloc_tree) {
4802 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4803 rc->block_rsv,
4804 rc->nodes_relocated, 1);
4805 if (ret)
4806 return ret;
4807 }
4808
4809 new_root = pending->snap;
4810 reloc_root = create_reloc_root(trans, root->reloc_root,
4811 new_root->root_key.objectid);
4812 if (IS_ERR(reloc_root))
4813 return PTR_ERR(reloc_root);
4814
4815 ret = __add_reloc_root(reloc_root);
4816 BUG_ON(ret < 0);
4817 new_root->reloc_root = reloc_root;
4818
4819 if (rc->create_reloc_tree)
4820 ret = clone_backref_node(trans, rc, root, reloc_root);
4821 return ret;
4822}