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