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