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