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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2009 Oracle. All rights reserved.
4 */
5
6#include <linux/sched.h>
7#include <linux/pagemap.h>
8#include <linux/writeback.h>
9#include <linux/blkdev.h>
10#include <linux/rbtree.h>
11#include <linux/slab.h>
12#include <linux/error-injection.h>
13#include "ctree.h"
14#include "disk-io.h"
15#include "transaction.h"
16#include "volumes.h"
17#include "locking.h"
18#include "btrfs_inode.h"
19#include "async-thread.h"
20#include "free-space-cache.h"
21#include "qgroup.h"
22#include "print-tree.h"
23#include "delalloc-space.h"
24#include "block-group.h"
25#include "backref.h"
26#include "misc.h"
27#include "subpage.h"
28#include "zoned.h"
29#include "inode-item.h"
30#include "space-info.h"
31#include "fs.h"
32#include "accessors.h"
33#include "extent-tree.h"
34#include "root-tree.h"
35#include "file-item.h"
36#include "relocation.h"
37#include "super.h"
38#include "tree-checker.h"
39
40/*
41 * Relocation overview
42 *
43 * [What does relocation do]
44 *
45 * The objective of relocation is to relocate all extents of the target block
46 * group to other block groups.
47 * This is utilized by resize (shrink only), profile converting, compacting
48 * space, or balance routine to spread chunks over devices.
49 *
50 * Before | After
51 * ------------------------------------------------------------------
52 * BG A: 10 data extents | BG A: deleted
53 * BG B: 2 data extents | BG B: 10 data extents (2 old + 8 relocated)
54 * BG C: 1 extents | BG C: 3 data extents (1 old + 2 relocated)
55 *
56 * [How does relocation work]
57 *
58 * 1. Mark the target block group read-only
59 * New extents won't be allocated from the target block group.
60 *
61 * 2.1 Record each extent in the target block group
62 * To build a proper map of extents to be relocated.
63 *
64 * 2.2 Build data reloc tree and reloc trees
65 * Data reloc tree will contain an inode, recording all newly relocated
66 * data extents.
67 * There will be only one data reloc tree for one data block group.
68 *
69 * Reloc tree will be a special snapshot of its source tree, containing
70 * relocated tree blocks.
71 * Each tree referring to a tree block in target block group will get its
72 * reloc tree built.
73 *
74 * 2.3 Swap source tree with its corresponding reloc tree
75 * Each involved tree only refers to new extents after swap.
76 *
77 * 3. Cleanup reloc trees and data reloc tree.
78 * As old extents in the target block group are still referenced by reloc
79 * trees, we need to clean them up before really freeing the target block
80 * group.
81 *
82 * The main complexity is in steps 2.2 and 2.3.
83 *
84 * The entry point of relocation is relocate_block_group() function.
85 */
86
87#define RELOCATION_RESERVED_NODES 256
88/*
89 * map address of tree root to tree
90 */
91struct mapping_node {
92 struct {
93 struct rb_node rb_node;
94 u64 bytenr;
95 }; /* Use rb_simle_node for search/insert */
96 void *data;
97};
98
99struct mapping_tree {
100 struct rb_root rb_root;
101 spinlock_t lock;
102};
103
104/*
105 * present a tree block to process
106 */
107struct tree_block {
108 struct {
109 struct rb_node rb_node;
110 u64 bytenr;
111 }; /* Use rb_simple_node for search/insert */
112 u64 owner;
113 struct btrfs_key key;
114 unsigned int level:8;
115 unsigned int key_ready:1;
116};
117
118#define MAX_EXTENTS 128
119
120struct file_extent_cluster {
121 u64 start;
122 u64 end;
123 u64 boundary[MAX_EXTENTS];
124 unsigned int nr;
125};
126
127struct reloc_control {
128 /* block group to relocate */
129 struct btrfs_block_group *block_group;
130 /* extent tree */
131 struct btrfs_root *extent_root;
132 /* inode for moving data */
133 struct inode *data_inode;
134
135 struct btrfs_block_rsv *block_rsv;
136
137 struct btrfs_backref_cache backref_cache;
138
139 struct file_extent_cluster cluster;
140 /* tree blocks have been processed */
141 struct extent_io_tree processed_blocks;
142 /* map start of tree root to corresponding reloc tree */
143 struct mapping_tree reloc_root_tree;
144 /* list of reloc trees */
145 struct list_head reloc_roots;
146 /* list of subvolume trees that get relocated */
147 struct list_head dirty_subvol_roots;
148 /* size of metadata reservation for merging reloc trees */
149 u64 merging_rsv_size;
150 /* size of relocated tree nodes */
151 u64 nodes_relocated;
152 /* reserved size for block group relocation*/
153 u64 reserved_bytes;
154
155 u64 search_start;
156 u64 extents_found;
157
158 unsigned int stage:8;
159 unsigned int create_reloc_tree:1;
160 unsigned int merge_reloc_tree:1;
161 unsigned int found_file_extent:1;
162};
163
164/* stages of data relocation */
165#define MOVE_DATA_EXTENTS 0
166#define UPDATE_DATA_PTRS 1
167
168static void mark_block_processed(struct reloc_control *rc,
169 struct btrfs_backref_node *node)
170{
171 u32 blocksize;
172
173 if (node->level == 0 ||
174 in_range(node->bytenr, rc->block_group->start,
175 rc->block_group->length)) {
176 blocksize = rc->extent_root->fs_info->nodesize;
177 set_extent_bits(&rc->processed_blocks, node->bytenr,
178 node->bytenr + blocksize - 1, EXTENT_DIRTY);
179 }
180 node->processed = 1;
181}
182
183
184static void mapping_tree_init(struct mapping_tree *tree)
185{
186 tree->rb_root = RB_ROOT;
187 spin_lock_init(&tree->lock);
188}
189
190/*
191 * walk up backref nodes until reach node presents tree root
192 */
193static struct btrfs_backref_node *walk_up_backref(
194 struct btrfs_backref_node *node,
195 struct btrfs_backref_edge *edges[], int *index)
196{
197 struct btrfs_backref_edge *edge;
198 int idx = *index;
199
200 while (!list_empty(&node->upper)) {
201 edge = list_entry(node->upper.next,
202 struct btrfs_backref_edge, list[LOWER]);
203 edges[idx++] = edge;
204 node = edge->node[UPPER];
205 }
206 BUG_ON(node->detached);
207 *index = idx;
208 return node;
209}
210
211/*
212 * walk down backref nodes to find start of next reference path
213 */
214static struct btrfs_backref_node *walk_down_backref(
215 struct btrfs_backref_edge *edges[], int *index)
216{
217 struct btrfs_backref_edge *edge;
218 struct btrfs_backref_node *lower;
219 int idx = *index;
220
221 while (idx > 0) {
222 edge = edges[idx - 1];
223 lower = edge->node[LOWER];
224 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
225 idx--;
226 continue;
227 }
228 edge = list_entry(edge->list[LOWER].next,
229 struct btrfs_backref_edge, list[LOWER]);
230 edges[idx - 1] = edge;
231 *index = idx;
232 return edge->node[UPPER];
233 }
234 *index = 0;
235 return NULL;
236}
237
238static void update_backref_node(struct btrfs_backref_cache *cache,
239 struct btrfs_backref_node *node, u64 bytenr)
240{
241 struct rb_node *rb_node;
242 rb_erase(&node->rb_node, &cache->rb_root);
243 node->bytenr = bytenr;
244 rb_node = rb_simple_insert(&cache->rb_root, node->bytenr, &node->rb_node);
245 if (rb_node)
246 btrfs_backref_panic(cache->fs_info, bytenr, -EEXIST);
247}
248
249/*
250 * update backref cache after a transaction commit
251 */
252static int update_backref_cache(struct btrfs_trans_handle *trans,
253 struct btrfs_backref_cache *cache)
254{
255 struct btrfs_backref_node *node;
256 int level = 0;
257
258 if (cache->last_trans == 0) {
259 cache->last_trans = trans->transid;
260 return 0;
261 }
262
263 if (cache->last_trans == trans->transid)
264 return 0;
265
266 /*
267 * detached nodes are used to avoid unnecessary backref
268 * lookup. transaction commit changes the extent tree.
269 * so the detached nodes are no longer useful.
270 */
271 while (!list_empty(&cache->detached)) {
272 node = list_entry(cache->detached.next,
273 struct btrfs_backref_node, list);
274 btrfs_backref_cleanup_node(cache, node);
275 }
276
277 while (!list_empty(&cache->changed)) {
278 node = list_entry(cache->changed.next,
279 struct btrfs_backref_node, list);
280 list_del_init(&node->list);
281 BUG_ON(node->pending);
282 update_backref_node(cache, node, node->new_bytenr);
283 }
284
285 /*
286 * some nodes can be left in the pending list if there were
287 * errors during processing the pending nodes.
288 */
289 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
290 list_for_each_entry(node, &cache->pending[level], list) {
291 BUG_ON(!node->pending);
292 if (node->bytenr == node->new_bytenr)
293 continue;
294 update_backref_node(cache, node, node->new_bytenr);
295 }
296 }
297
298 cache->last_trans = 0;
299 return 1;
300}
301
302static bool reloc_root_is_dead(struct btrfs_root *root)
303{
304 /*
305 * Pair with set_bit/clear_bit in clean_dirty_subvols and
306 * btrfs_update_reloc_root. We need to see the updated bit before
307 * trying to access reloc_root
308 */
309 smp_rmb();
310 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state))
311 return true;
312 return false;
313}
314
315/*
316 * Check if this subvolume tree has valid reloc tree.
317 *
318 * Reloc tree after swap is considered dead, thus not considered as valid.
319 * This is enough for most callers, as they don't distinguish dead reloc root
320 * from no reloc root. But btrfs_should_ignore_reloc_root() below is a
321 * special case.
322 */
323static bool have_reloc_root(struct btrfs_root *root)
324{
325 if (reloc_root_is_dead(root))
326 return false;
327 if (!root->reloc_root)
328 return false;
329 return true;
330}
331
332int btrfs_should_ignore_reloc_root(struct btrfs_root *root)
333{
334 struct btrfs_root *reloc_root;
335
336 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
337 return 0;
338
339 /* This root has been merged with its reloc tree, we can ignore it */
340 if (reloc_root_is_dead(root))
341 return 1;
342
343 reloc_root = root->reloc_root;
344 if (!reloc_root)
345 return 0;
346
347 if (btrfs_header_generation(reloc_root->commit_root) ==
348 root->fs_info->running_transaction->transid)
349 return 0;
350 /*
351 * if there is reloc tree and it was created in previous
352 * transaction backref lookup can find the reloc tree,
353 * so backref node for the fs tree root is useless for
354 * relocation.
355 */
356 return 1;
357}
358
359/*
360 * find reloc tree by address of tree root
361 */
362struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr)
363{
364 struct reloc_control *rc = fs_info->reloc_ctl;
365 struct rb_node *rb_node;
366 struct mapping_node *node;
367 struct btrfs_root *root = NULL;
368
369 ASSERT(rc);
370 spin_lock(&rc->reloc_root_tree.lock);
371 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, bytenr);
372 if (rb_node) {
373 node = rb_entry(rb_node, struct mapping_node, rb_node);
374 root = node->data;
375 }
376 spin_unlock(&rc->reloc_root_tree.lock);
377 return btrfs_grab_root(root);
378}
379
380/*
381 * For useless nodes, do two major clean ups:
382 *
383 * - Cleanup the children edges and nodes
384 * If child node is also orphan (no parent) during cleanup, then the child
385 * node will also be cleaned up.
386 *
387 * - Freeing up leaves (level 0), keeps nodes detached
388 * For nodes, the node is still cached as "detached"
389 *
390 * Return false if @node is not in the @useless_nodes list.
391 * Return true if @node is in the @useless_nodes list.
392 */
393static bool handle_useless_nodes(struct reloc_control *rc,
394 struct btrfs_backref_node *node)
395{
396 struct btrfs_backref_cache *cache = &rc->backref_cache;
397 struct list_head *useless_node = &cache->useless_node;
398 bool ret = false;
399
400 while (!list_empty(useless_node)) {
401 struct btrfs_backref_node *cur;
402
403 cur = list_first_entry(useless_node, struct btrfs_backref_node,
404 list);
405 list_del_init(&cur->list);
406
407 /* Only tree root nodes can be added to @useless_nodes */
408 ASSERT(list_empty(&cur->upper));
409
410 if (cur == node)
411 ret = true;
412
413 /* The node is the lowest node */
414 if (cur->lowest) {
415 list_del_init(&cur->lower);
416 cur->lowest = 0;
417 }
418
419 /* Cleanup the lower edges */
420 while (!list_empty(&cur->lower)) {
421 struct btrfs_backref_edge *edge;
422 struct btrfs_backref_node *lower;
423
424 edge = list_entry(cur->lower.next,
425 struct btrfs_backref_edge, list[UPPER]);
426 list_del(&edge->list[UPPER]);
427 list_del(&edge->list[LOWER]);
428 lower = edge->node[LOWER];
429 btrfs_backref_free_edge(cache, edge);
430
431 /* Child node is also orphan, queue for cleanup */
432 if (list_empty(&lower->upper))
433 list_add(&lower->list, useless_node);
434 }
435 /* Mark this block processed for relocation */
436 mark_block_processed(rc, cur);
437
438 /*
439 * Backref nodes for tree leaves are deleted from the cache.
440 * Backref nodes for upper level tree blocks are left in the
441 * cache to avoid unnecessary backref lookup.
442 */
443 if (cur->level > 0) {
444 list_add(&cur->list, &cache->detached);
445 cur->detached = 1;
446 } else {
447 rb_erase(&cur->rb_node, &cache->rb_root);
448 btrfs_backref_free_node(cache, cur);
449 }
450 }
451 return ret;
452}
453
454/*
455 * Build backref tree for a given tree block. Root of the backref tree
456 * corresponds the tree block, leaves of the backref tree correspond roots of
457 * b-trees that reference the tree block.
458 *
459 * The basic idea of this function is check backrefs of a given block to find
460 * upper level blocks that reference the block, and then check backrefs of
461 * these upper level blocks recursively. The recursion stops when tree root is
462 * reached or backrefs for the block is cached.
463 *
464 * NOTE: if we find that backrefs for a block are cached, we know backrefs for
465 * all upper level blocks that directly/indirectly reference the block are also
466 * cached.
467 */
468static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
469 struct reloc_control *rc, struct btrfs_key *node_key,
470 int level, u64 bytenr)
471{
472 struct btrfs_backref_iter *iter;
473 struct btrfs_backref_cache *cache = &rc->backref_cache;
474 /* For searching parent of TREE_BLOCK_REF */
475 struct btrfs_path *path;
476 struct btrfs_backref_node *cur;
477 struct btrfs_backref_node *node = NULL;
478 struct btrfs_backref_edge *edge;
479 int ret;
480 int err = 0;
481
482 iter = btrfs_backref_iter_alloc(rc->extent_root->fs_info);
483 if (!iter)
484 return ERR_PTR(-ENOMEM);
485 path = btrfs_alloc_path();
486 if (!path) {
487 err = -ENOMEM;
488 goto out;
489 }
490
491 node = btrfs_backref_alloc_node(cache, bytenr, level);
492 if (!node) {
493 err = -ENOMEM;
494 goto out;
495 }
496
497 node->lowest = 1;
498 cur = node;
499
500 /* Breadth-first search to build backref cache */
501 do {
502 ret = btrfs_backref_add_tree_node(cache, path, iter, node_key,
503 cur);
504 if (ret < 0) {
505 err = ret;
506 goto out;
507 }
508 edge = list_first_entry_or_null(&cache->pending_edge,
509 struct btrfs_backref_edge, list[UPPER]);
510 /*
511 * The pending list isn't empty, take the first block to
512 * process
513 */
514 if (edge) {
515 list_del_init(&edge->list[UPPER]);
516 cur = edge->node[UPPER];
517 }
518 } while (edge);
519
520 /* Finish the upper linkage of newly added edges/nodes */
521 ret = btrfs_backref_finish_upper_links(cache, node);
522 if (ret < 0) {
523 err = ret;
524 goto out;
525 }
526
527 if (handle_useless_nodes(rc, node))
528 node = NULL;
529out:
530 btrfs_backref_iter_free(iter);
531 btrfs_free_path(path);
532 if (err) {
533 btrfs_backref_error_cleanup(cache, node);
534 return ERR_PTR(err);
535 }
536 ASSERT(!node || !node->detached);
537 ASSERT(list_empty(&cache->useless_node) &&
538 list_empty(&cache->pending_edge));
539 return node;
540}
541
542/*
543 * helper to add backref node for the newly created snapshot.
544 * the backref node is created by cloning backref node that
545 * corresponds to root of source tree
546 */
547static int clone_backref_node(struct btrfs_trans_handle *trans,
548 struct reloc_control *rc,
549 struct btrfs_root *src,
550 struct btrfs_root *dest)
551{
552 struct btrfs_root *reloc_root = src->reloc_root;
553 struct btrfs_backref_cache *cache = &rc->backref_cache;
554 struct btrfs_backref_node *node = NULL;
555 struct btrfs_backref_node *new_node;
556 struct btrfs_backref_edge *edge;
557 struct btrfs_backref_edge *new_edge;
558 struct rb_node *rb_node;
559
560 if (cache->last_trans > 0)
561 update_backref_cache(trans, cache);
562
563 rb_node = rb_simple_search(&cache->rb_root, src->commit_root->start);
564 if (rb_node) {
565 node = rb_entry(rb_node, struct btrfs_backref_node, rb_node);
566 if (node->detached)
567 node = NULL;
568 else
569 BUG_ON(node->new_bytenr != reloc_root->node->start);
570 }
571
572 if (!node) {
573 rb_node = rb_simple_search(&cache->rb_root,
574 reloc_root->commit_root->start);
575 if (rb_node) {
576 node = rb_entry(rb_node, struct btrfs_backref_node,
577 rb_node);
578 BUG_ON(node->detached);
579 }
580 }
581
582 if (!node)
583 return 0;
584
585 new_node = btrfs_backref_alloc_node(cache, dest->node->start,
586 node->level);
587 if (!new_node)
588 return -ENOMEM;
589
590 new_node->lowest = node->lowest;
591 new_node->checked = 1;
592 new_node->root = btrfs_grab_root(dest);
593 ASSERT(new_node->root);
594
595 if (!node->lowest) {
596 list_for_each_entry(edge, &node->lower, list[UPPER]) {
597 new_edge = btrfs_backref_alloc_edge(cache);
598 if (!new_edge)
599 goto fail;
600
601 btrfs_backref_link_edge(new_edge, edge->node[LOWER],
602 new_node, LINK_UPPER);
603 }
604 } else {
605 list_add_tail(&new_node->lower, &cache->leaves);
606 }
607
608 rb_node = rb_simple_insert(&cache->rb_root, new_node->bytenr,
609 &new_node->rb_node);
610 if (rb_node)
611 btrfs_backref_panic(trans->fs_info, new_node->bytenr, -EEXIST);
612
613 if (!new_node->lowest) {
614 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
615 list_add_tail(&new_edge->list[LOWER],
616 &new_edge->node[LOWER]->upper);
617 }
618 }
619 return 0;
620fail:
621 while (!list_empty(&new_node->lower)) {
622 new_edge = list_entry(new_node->lower.next,
623 struct btrfs_backref_edge, list[UPPER]);
624 list_del(&new_edge->list[UPPER]);
625 btrfs_backref_free_edge(cache, new_edge);
626 }
627 btrfs_backref_free_node(cache, new_node);
628 return -ENOMEM;
629}
630
631/*
632 * helper to add 'address of tree root -> reloc tree' mapping
633 */
634static int __must_check __add_reloc_root(struct btrfs_root *root)
635{
636 struct btrfs_fs_info *fs_info = root->fs_info;
637 struct rb_node *rb_node;
638 struct mapping_node *node;
639 struct reloc_control *rc = fs_info->reloc_ctl;
640
641 node = kmalloc(sizeof(*node), GFP_NOFS);
642 if (!node)
643 return -ENOMEM;
644
645 node->bytenr = root->commit_root->start;
646 node->data = root;
647
648 spin_lock(&rc->reloc_root_tree.lock);
649 rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
650 node->bytenr, &node->rb_node);
651 spin_unlock(&rc->reloc_root_tree.lock);
652 if (rb_node) {
653 btrfs_err(fs_info,
654 "Duplicate root found for start=%llu while inserting into relocation tree",
655 node->bytenr);
656 return -EEXIST;
657 }
658
659 list_add_tail(&root->root_list, &rc->reloc_roots);
660 return 0;
661}
662
663/*
664 * helper to delete the 'address of tree root -> reloc tree'
665 * mapping
666 */
667static void __del_reloc_root(struct btrfs_root *root)
668{
669 struct btrfs_fs_info *fs_info = root->fs_info;
670 struct rb_node *rb_node;
671 struct mapping_node *node = NULL;
672 struct reloc_control *rc = fs_info->reloc_ctl;
673 bool put_ref = false;
674
675 if (rc && root->node) {
676 spin_lock(&rc->reloc_root_tree.lock);
677 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
678 root->commit_root->start);
679 if (rb_node) {
680 node = rb_entry(rb_node, struct mapping_node, rb_node);
681 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
682 RB_CLEAR_NODE(&node->rb_node);
683 }
684 spin_unlock(&rc->reloc_root_tree.lock);
685 ASSERT(!node || (struct btrfs_root *)node->data == root);
686 }
687
688 /*
689 * We only put the reloc root here if it's on the list. There's a lot
690 * of places where the pattern is to splice the rc->reloc_roots, process
691 * the reloc roots, and then add the reloc root back onto
692 * rc->reloc_roots. If we call __del_reloc_root while it's off of the
693 * list we don't want the reference being dropped, because the guy
694 * messing with the list is in charge of the reference.
695 */
696 spin_lock(&fs_info->trans_lock);
697 if (!list_empty(&root->root_list)) {
698 put_ref = true;
699 list_del_init(&root->root_list);
700 }
701 spin_unlock(&fs_info->trans_lock);
702 if (put_ref)
703 btrfs_put_root(root);
704 kfree(node);
705}
706
707/*
708 * helper to update the 'address of tree root -> reloc tree'
709 * mapping
710 */
711static int __update_reloc_root(struct btrfs_root *root)
712{
713 struct btrfs_fs_info *fs_info = root->fs_info;
714 struct rb_node *rb_node;
715 struct mapping_node *node = NULL;
716 struct reloc_control *rc = fs_info->reloc_ctl;
717
718 spin_lock(&rc->reloc_root_tree.lock);
719 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
720 root->commit_root->start);
721 if (rb_node) {
722 node = rb_entry(rb_node, struct mapping_node, rb_node);
723 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
724 }
725 spin_unlock(&rc->reloc_root_tree.lock);
726
727 if (!node)
728 return 0;
729 BUG_ON((struct btrfs_root *)node->data != root);
730
731 spin_lock(&rc->reloc_root_tree.lock);
732 node->bytenr = root->node->start;
733 rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
734 node->bytenr, &node->rb_node);
735 spin_unlock(&rc->reloc_root_tree.lock);
736 if (rb_node)
737 btrfs_backref_panic(fs_info, node->bytenr, -EEXIST);
738 return 0;
739}
740
741static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
742 struct btrfs_root *root, u64 objectid)
743{
744 struct btrfs_fs_info *fs_info = root->fs_info;
745 struct btrfs_root *reloc_root;
746 struct extent_buffer *eb;
747 struct btrfs_root_item *root_item;
748 struct btrfs_key root_key;
749 int ret = 0;
750 bool must_abort = false;
751
752 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
753 if (!root_item)
754 return ERR_PTR(-ENOMEM);
755
756 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
757 root_key.type = BTRFS_ROOT_ITEM_KEY;
758 root_key.offset = objectid;
759
760 if (root->root_key.objectid == objectid) {
761 u64 commit_root_gen;
762
763 /* called by btrfs_init_reloc_root */
764 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
765 BTRFS_TREE_RELOC_OBJECTID);
766 if (ret)
767 goto fail;
768
769 /*
770 * Set the last_snapshot field to the generation of the commit
771 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
772 * correctly (returns true) when the relocation root is created
773 * either inside the critical section of a transaction commit
774 * (through transaction.c:qgroup_account_snapshot()) and when
775 * it's created before the transaction commit is started.
776 */
777 commit_root_gen = btrfs_header_generation(root->commit_root);
778 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
779 } else {
780 /*
781 * called by btrfs_reloc_post_snapshot_hook.
782 * the source tree is a reloc tree, all tree blocks
783 * modified after it was created have RELOC flag
784 * set in their headers. so it's OK to not update
785 * the 'last_snapshot'.
786 */
787 ret = btrfs_copy_root(trans, root, root->node, &eb,
788 BTRFS_TREE_RELOC_OBJECTID);
789 if (ret)
790 goto fail;
791 }
792
793 /*
794 * We have changed references at this point, we must abort the
795 * transaction if anything fails.
796 */
797 must_abort = true;
798
799 memcpy(root_item, &root->root_item, sizeof(*root_item));
800 btrfs_set_root_bytenr(root_item, eb->start);
801 btrfs_set_root_level(root_item, btrfs_header_level(eb));
802 btrfs_set_root_generation(root_item, trans->transid);
803
804 if (root->root_key.objectid == objectid) {
805 btrfs_set_root_refs(root_item, 0);
806 memset(&root_item->drop_progress, 0,
807 sizeof(struct btrfs_disk_key));
808 btrfs_set_root_drop_level(root_item, 0);
809 }
810
811 btrfs_tree_unlock(eb);
812 free_extent_buffer(eb);
813
814 ret = btrfs_insert_root(trans, fs_info->tree_root,
815 &root_key, root_item);
816 if (ret)
817 goto fail;
818
819 kfree(root_item);
820
821 reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key);
822 if (IS_ERR(reloc_root)) {
823 ret = PTR_ERR(reloc_root);
824 goto abort;
825 }
826 set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
827 reloc_root->last_trans = trans->transid;
828 return reloc_root;
829fail:
830 kfree(root_item);
831abort:
832 if (must_abort)
833 btrfs_abort_transaction(trans, ret);
834 return ERR_PTR(ret);
835}
836
837/*
838 * create reloc tree for a given fs tree. reloc tree is just a
839 * snapshot of the fs tree with special root objectid.
840 *
841 * The reloc_root comes out of here with two references, one for
842 * root->reloc_root, and another for being on the rc->reloc_roots list.
843 */
844int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
845 struct btrfs_root *root)
846{
847 struct btrfs_fs_info *fs_info = root->fs_info;
848 struct btrfs_root *reloc_root;
849 struct reloc_control *rc = fs_info->reloc_ctl;
850 struct btrfs_block_rsv *rsv;
851 int clear_rsv = 0;
852 int ret;
853
854 if (!rc)
855 return 0;
856
857 /*
858 * The subvolume has reloc tree but the swap is finished, no need to
859 * create/update the dead reloc tree
860 */
861 if (reloc_root_is_dead(root))
862 return 0;
863
864 /*
865 * This is subtle but important. We do not do
866 * record_root_in_transaction for reloc roots, instead we record their
867 * corresponding fs root, and then here we update the last trans for the
868 * reloc root. This means that we have to do this for the entire life
869 * of the reloc root, regardless of which stage of the relocation we are
870 * in.
871 */
872 if (root->reloc_root) {
873 reloc_root = root->reloc_root;
874 reloc_root->last_trans = trans->transid;
875 return 0;
876 }
877
878 /*
879 * We are merging reloc roots, we do not need new reloc trees. Also
880 * reloc trees never need their own reloc tree.
881 */
882 if (!rc->create_reloc_tree ||
883 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
884 return 0;
885
886 if (!trans->reloc_reserved) {
887 rsv = trans->block_rsv;
888 trans->block_rsv = rc->block_rsv;
889 clear_rsv = 1;
890 }
891 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
892 if (clear_rsv)
893 trans->block_rsv = rsv;
894 if (IS_ERR(reloc_root))
895 return PTR_ERR(reloc_root);
896
897 ret = __add_reloc_root(reloc_root);
898 ASSERT(ret != -EEXIST);
899 if (ret) {
900 /* Pairs with create_reloc_root */
901 btrfs_put_root(reloc_root);
902 return ret;
903 }
904 root->reloc_root = btrfs_grab_root(reloc_root);
905 return 0;
906}
907
908/*
909 * update root item of reloc tree
910 */
911int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
912 struct btrfs_root *root)
913{
914 struct btrfs_fs_info *fs_info = root->fs_info;
915 struct btrfs_root *reloc_root;
916 struct btrfs_root_item *root_item;
917 int ret;
918
919 if (!have_reloc_root(root))
920 return 0;
921
922 reloc_root = root->reloc_root;
923 root_item = &reloc_root->root_item;
924
925 /*
926 * We are probably ok here, but __del_reloc_root() will drop its ref of
927 * the root. We have the ref for root->reloc_root, but just in case
928 * hold it while we update the reloc root.
929 */
930 btrfs_grab_root(reloc_root);
931
932 /* root->reloc_root will stay until current relocation finished */
933 if (fs_info->reloc_ctl->merge_reloc_tree &&
934 btrfs_root_refs(root_item) == 0) {
935 set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
936 /*
937 * Mark the tree as dead before we change reloc_root so
938 * have_reloc_root will not touch it from now on.
939 */
940 smp_wmb();
941 __del_reloc_root(reloc_root);
942 }
943
944 if (reloc_root->commit_root != reloc_root->node) {
945 __update_reloc_root(reloc_root);
946 btrfs_set_root_node(root_item, reloc_root->node);
947 free_extent_buffer(reloc_root->commit_root);
948 reloc_root->commit_root = btrfs_root_node(reloc_root);
949 }
950
951 ret = btrfs_update_root(trans, fs_info->tree_root,
952 &reloc_root->root_key, root_item);
953 btrfs_put_root(reloc_root);
954 return ret;
955}
956
957/*
958 * helper to find first cached inode with inode number >= objectid
959 * in a subvolume
960 */
961static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
962{
963 struct rb_node *node;
964 struct rb_node *prev;
965 struct btrfs_inode *entry;
966 struct inode *inode;
967
968 spin_lock(&root->inode_lock);
969again:
970 node = root->inode_tree.rb_node;
971 prev = NULL;
972 while (node) {
973 prev = node;
974 entry = rb_entry(node, struct btrfs_inode, rb_node);
975
976 if (objectid < btrfs_ino(entry))
977 node = node->rb_left;
978 else if (objectid > btrfs_ino(entry))
979 node = node->rb_right;
980 else
981 break;
982 }
983 if (!node) {
984 while (prev) {
985 entry = rb_entry(prev, struct btrfs_inode, rb_node);
986 if (objectid <= btrfs_ino(entry)) {
987 node = prev;
988 break;
989 }
990 prev = rb_next(prev);
991 }
992 }
993 while (node) {
994 entry = rb_entry(node, struct btrfs_inode, rb_node);
995 inode = igrab(&entry->vfs_inode);
996 if (inode) {
997 spin_unlock(&root->inode_lock);
998 return inode;
999 }
1000
1001 objectid = btrfs_ino(entry) + 1;
1002 if (cond_resched_lock(&root->inode_lock))
1003 goto again;
1004
1005 node = rb_next(node);
1006 }
1007 spin_unlock(&root->inode_lock);
1008 return NULL;
1009}
1010
1011/*
1012 * get new location of data
1013 */
1014static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1015 u64 bytenr, u64 num_bytes)
1016{
1017 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1018 struct btrfs_path *path;
1019 struct btrfs_file_extent_item *fi;
1020 struct extent_buffer *leaf;
1021 int ret;
1022
1023 path = btrfs_alloc_path();
1024 if (!path)
1025 return -ENOMEM;
1026
1027 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1028 ret = btrfs_lookup_file_extent(NULL, root, path,
1029 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1030 if (ret < 0)
1031 goto out;
1032 if (ret > 0) {
1033 ret = -ENOENT;
1034 goto out;
1035 }
1036
1037 leaf = path->nodes[0];
1038 fi = btrfs_item_ptr(leaf, path->slots[0],
1039 struct btrfs_file_extent_item);
1040
1041 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1042 btrfs_file_extent_compression(leaf, fi) ||
1043 btrfs_file_extent_encryption(leaf, fi) ||
1044 btrfs_file_extent_other_encoding(leaf, fi));
1045
1046 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1047 ret = -EINVAL;
1048 goto out;
1049 }
1050
1051 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1052 ret = 0;
1053out:
1054 btrfs_free_path(path);
1055 return ret;
1056}
1057
1058/*
1059 * update file extent items in the tree leaf to point to
1060 * the new locations.
1061 */
1062static noinline_for_stack
1063int replace_file_extents(struct btrfs_trans_handle *trans,
1064 struct reloc_control *rc,
1065 struct btrfs_root *root,
1066 struct extent_buffer *leaf)
1067{
1068 struct btrfs_fs_info *fs_info = root->fs_info;
1069 struct btrfs_key key;
1070 struct btrfs_file_extent_item *fi;
1071 struct inode *inode = NULL;
1072 u64 parent;
1073 u64 bytenr;
1074 u64 new_bytenr = 0;
1075 u64 num_bytes;
1076 u64 end;
1077 u32 nritems;
1078 u32 i;
1079 int ret = 0;
1080 int first = 1;
1081 int dirty = 0;
1082
1083 if (rc->stage != UPDATE_DATA_PTRS)
1084 return 0;
1085
1086 /* reloc trees always use full backref */
1087 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1088 parent = leaf->start;
1089 else
1090 parent = 0;
1091
1092 nritems = btrfs_header_nritems(leaf);
1093 for (i = 0; i < nritems; i++) {
1094 struct btrfs_ref ref = { 0 };
1095
1096 cond_resched();
1097 btrfs_item_key_to_cpu(leaf, &key, i);
1098 if (key.type != BTRFS_EXTENT_DATA_KEY)
1099 continue;
1100 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1101 if (btrfs_file_extent_type(leaf, fi) ==
1102 BTRFS_FILE_EXTENT_INLINE)
1103 continue;
1104 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1105 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1106 if (bytenr == 0)
1107 continue;
1108 if (!in_range(bytenr, rc->block_group->start,
1109 rc->block_group->length))
1110 continue;
1111
1112 /*
1113 * if we are modifying block in fs tree, wait for read_folio
1114 * to complete and drop the extent cache
1115 */
1116 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1117 if (first) {
1118 inode = find_next_inode(root, key.objectid);
1119 first = 0;
1120 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1121 btrfs_add_delayed_iput(BTRFS_I(inode));
1122 inode = find_next_inode(root, key.objectid);
1123 }
1124 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1125 struct extent_state *cached_state = NULL;
1126
1127 end = key.offset +
1128 btrfs_file_extent_num_bytes(leaf, fi);
1129 WARN_ON(!IS_ALIGNED(key.offset,
1130 fs_info->sectorsize));
1131 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1132 end--;
1133 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1134 key.offset, end,
1135 &cached_state);
1136 if (!ret)
1137 continue;
1138
1139 btrfs_drop_extent_map_range(BTRFS_I(inode),
1140 key.offset, end, true);
1141 unlock_extent(&BTRFS_I(inode)->io_tree,
1142 key.offset, end, &cached_state);
1143 }
1144 }
1145
1146 ret = get_new_location(rc->data_inode, &new_bytenr,
1147 bytenr, num_bytes);
1148 if (ret) {
1149 /*
1150 * Don't have to abort since we've not changed anything
1151 * in the file extent yet.
1152 */
1153 break;
1154 }
1155
1156 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1157 dirty = 1;
1158
1159 key.offset -= btrfs_file_extent_offset(leaf, fi);
1160 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1161 num_bytes, parent);
1162 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1163 key.objectid, key.offset,
1164 root->root_key.objectid, false);
1165 ret = btrfs_inc_extent_ref(trans, &ref);
1166 if (ret) {
1167 btrfs_abort_transaction(trans, ret);
1168 break;
1169 }
1170
1171 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1172 num_bytes, parent);
1173 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1174 key.objectid, key.offset,
1175 root->root_key.objectid, false);
1176 ret = btrfs_free_extent(trans, &ref);
1177 if (ret) {
1178 btrfs_abort_transaction(trans, ret);
1179 break;
1180 }
1181 }
1182 if (dirty)
1183 btrfs_mark_buffer_dirty(leaf);
1184 if (inode)
1185 btrfs_add_delayed_iput(BTRFS_I(inode));
1186 return ret;
1187}
1188
1189static noinline_for_stack
1190int memcmp_node_keys(struct extent_buffer *eb, int slot,
1191 struct btrfs_path *path, int level)
1192{
1193 struct btrfs_disk_key key1;
1194 struct btrfs_disk_key key2;
1195 btrfs_node_key(eb, &key1, slot);
1196 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1197 return memcmp(&key1, &key2, sizeof(key1));
1198}
1199
1200/*
1201 * try to replace tree blocks in fs tree with the new blocks
1202 * in reloc tree. tree blocks haven't been modified since the
1203 * reloc tree was create can be replaced.
1204 *
1205 * if a block was replaced, level of the block + 1 is returned.
1206 * if no block got replaced, 0 is returned. if there are other
1207 * errors, a negative error number is returned.
1208 */
1209static noinline_for_stack
1210int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1211 struct btrfs_root *dest, struct btrfs_root *src,
1212 struct btrfs_path *path, struct btrfs_key *next_key,
1213 int lowest_level, int max_level)
1214{
1215 struct btrfs_fs_info *fs_info = dest->fs_info;
1216 struct extent_buffer *eb;
1217 struct extent_buffer *parent;
1218 struct btrfs_ref ref = { 0 };
1219 struct btrfs_key key;
1220 u64 old_bytenr;
1221 u64 new_bytenr;
1222 u64 old_ptr_gen;
1223 u64 new_ptr_gen;
1224 u64 last_snapshot;
1225 u32 blocksize;
1226 int cow = 0;
1227 int level;
1228 int ret;
1229 int slot;
1230
1231 ASSERT(src->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1232 ASSERT(dest->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1233
1234 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1235again:
1236 slot = path->slots[lowest_level];
1237 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1238
1239 eb = btrfs_lock_root_node(dest);
1240 level = btrfs_header_level(eb);
1241
1242 if (level < lowest_level) {
1243 btrfs_tree_unlock(eb);
1244 free_extent_buffer(eb);
1245 return 0;
1246 }
1247
1248 if (cow) {
1249 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb,
1250 BTRFS_NESTING_COW);
1251 if (ret) {
1252 btrfs_tree_unlock(eb);
1253 free_extent_buffer(eb);
1254 return ret;
1255 }
1256 }
1257
1258 if (next_key) {
1259 next_key->objectid = (u64)-1;
1260 next_key->type = (u8)-1;
1261 next_key->offset = (u64)-1;
1262 }
1263
1264 parent = eb;
1265 while (1) {
1266 level = btrfs_header_level(parent);
1267 ASSERT(level >= lowest_level);
1268
1269 ret = btrfs_bin_search(parent, &key, &slot);
1270 if (ret < 0)
1271 break;
1272 if (ret && slot > 0)
1273 slot--;
1274
1275 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1276 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1277
1278 old_bytenr = btrfs_node_blockptr(parent, slot);
1279 blocksize = fs_info->nodesize;
1280 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1281
1282 if (level <= max_level) {
1283 eb = path->nodes[level];
1284 new_bytenr = btrfs_node_blockptr(eb,
1285 path->slots[level]);
1286 new_ptr_gen = btrfs_node_ptr_generation(eb,
1287 path->slots[level]);
1288 } else {
1289 new_bytenr = 0;
1290 new_ptr_gen = 0;
1291 }
1292
1293 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1294 ret = level;
1295 break;
1296 }
1297
1298 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1299 memcmp_node_keys(parent, slot, path, level)) {
1300 if (level <= lowest_level) {
1301 ret = 0;
1302 break;
1303 }
1304
1305 eb = btrfs_read_node_slot(parent, slot);
1306 if (IS_ERR(eb)) {
1307 ret = PTR_ERR(eb);
1308 break;
1309 }
1310 btrfs_tree_lock(eb);
1311 if (cow) {
1312 ret = btrfs_cow_block(trans, dest, eb, parent,
1313 slot, &eb,
1314 BTRFS_NESTING_COW);
1315 if (ret) {
1316 btrfs_tree_unlock(eb);
1317 free_extent_buffer(eb);
1318 break;
1319 }
1320 }
1321
1322 btrfs_tree_unlock(parent);
1323 free_extent_buffer(parent);
1324
1325 parent = eb;
1326 continue;
1327 }
1328
1329 if (!cow) {
1330 btrfs_tree_unlock(parent);
1331 free_extent_buffer(parent);
1332 cow = 1;
1333 goto again;
1334 }
1335
1336 btrfs_node_key_to_cpu(path->nodes[level], &key,
1337 path->slots[level]);
1338 btrfs_release_path(path);
1339
1340 path->lowest_level = level;
1341 set_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state);
1342 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1343 clear_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state);
1344 path->lowest_level = 0;
1345 if (ret) {
1346 if (ret > 0)
1347 ret = -ENOENT;
1348 break;
1349 }
1350
1351 /*
1352 * Info qgroup to trace both subtrees.
1353 *
1354 * We must trace both trees.
1355 * 1) Tree reloc subtree
1356 * If not traced, we will leak data numbers
1357 * 2) Fs subtree
1358 * If not traced, we will double count old data
1359 *
1360 * We don't scan the subtree right now, but only record
1361 * the swapped tree blocks.
1362 * The real subtree rescan is delayed until we have new
1363 * CoW on the subtree root node before transaction commit.
1364 */
1365 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1366 rc->block_group, parent, slot,
1367 path->nodes[level], path->slots[level],
1368 last_snapshot);
1369 if (ret < 0)
1370 break;
1371 /*
1372 * swap blocks in fs tree and reloc tree.
1373 */
1374 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1375 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1376 btrfs_mark_buffer_dirty(parent);
1377
1378 btrfs_set_node_blockptr(path->nodes[level],
1379 path->slots[level], old_bytenr);
1380 btrfs_set_node_ptr_generation(path->nodes[level],
1381 path->slots[level], old_ptr_gen);
1382 btrfs_mark_buffer_dirty(path->nodes[level]);
1383
1384 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
1385 blocksize, path->nodes[level]->start);
1386 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid,
1387 0, true);
1388 ret = btrfs_inc_extent_ref(trans, &ref);
1389 if (ret) {
1390 btrfs_abort_transaction(trans, ret);
1391 break;
1392 }
1393 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1394 blocksize, 0);
1395 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid, 0,
1396 true);
1397 ret = btrfs_inc_extent_ref(trans, &ref);
1398 if (ret) {
1399 btrfs_abort_transaction(trans, ret);
1400 break;
1401 }
1402
1403 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
1404 blocksize, path->nodes[level]->start);
1405 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid,
1406 0, true);
1407 ret = btrfs_free_extent(trans, &ref);
1408 if (ret) {
1409 btrfs_abort_transaction(trans, ret);
1410 break;
1411 }
1412
1413 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1414 blocksize, 0);
1415 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid,
1416 0, true);
1417 ret = btrfs_free_extent(trans, &ref);
1418 if (ret) {
1419 btrfs_abort_transaction(trans, ret);
1420 break;
1421 }
1422
1423 btrfs_unlock_up_safe(path, 0);
1424
1425 ret = level;
1426 break;
1427 }
1428 btrfs_tree_unlock(parent);
1429 free_extent_buffer(parent);
1430 return ret;
1431}
1432
1433/*
1434 * helper to find next relocated block in reloc tree
1435 */
1436static noinline_for_stack
1437int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1438 int *level)
1439{
1440 struct extent_buffer *eb;
1441 int i;
1442 u64 last_snapshot;
1443 u32 nritems;
1444
1445 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1446
1447 for (i = 0; i < *level; i++) {
1448 free_extent_buffer(path->nodes[i]);
1449 path->nodes[i] = NULL;
1450 }
1451
1452 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1453 eb = path->nodes[i];
1454 nritems = btrfs_header_nritems(eb);
1455 while (path->slots[i] + 1 < nritems) {
1456 path->slots[i]++;
1457 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1458 last_snapshot)
1459 continue;
1460
1461 *level = i;
1462 return 0;
1463 }
1464 free_extent_buffer(path->nodes[i]);
1465 path->nodes[i] = NULL;
1466 }
1467 return 1;
1468}
1469
1470/*
1471 * walk down reloc tree to find relocated block of lowest level
1472 */
1473static noinline_for_stack
1474int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1475 int *level)
1476{
1477 struct extent_buffer *eb = NULL;
1478 int i;
1479 u64 ptr_gen = 0;
1480 u64 last_snapshot;
1481 u32 nritems;
1482
1483 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1484
1485 for (i = *level; i > 0; i--) {
1486 eb = path->nodes[i];
1487 nritems = btrfs_header_nritems(eb);
1488 while (path->slots[i] < nritems) {
1489 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1490 if (ptr_gen > last_snapshot)
1491 break;
1492 path->slots[i]++;
1493 }
1494 if (path->slots[i] >= nritems) {
1495 if (i == *level)
1496 break;
1497 *level = i + 1;
1498 return 0;
1499 }
1500 if (i == 1) {
1501 *level = i;
1502 return 0;
1503 }
1504
1505 eb = btrfs_read_node_slot(eb, path->slots[i]);
1506 if (IS_ERR(eb))
1507 return PTR_ERR(eb);
1508 BUG_ON(btrfs_header_level(eb) != i - 1);
1509 path->nodes[i - 1] = eb;
1510 path->slots[i - 1] = 0;
1511 }
1512 return 1;
1513}
1514
1515/*
1516 * invalidate extent cache for file extents whose key in range of
1517 * [min_key, max_key)
1518 */
1519static int invalidate_extent_cache(struct btrfs_root *root,
1520 struct btrfs_key *min_key,
1521 struct btrfs_key *max_key)
1522{
1523 struct btrfs_fs_info *fs_info = root->fs_info;
1524 struct inode *inode = NULL;
1525 u64 objectid;
1526 u64 start, end;
1527 u64 ino;
1528
1529 objectid = min_key->objectid;
1530 while (1) {
1531 struct extent_state *cached_state = NULL;
1532
1533 cond_resched();
1534 iput(inode);
1535
1536 if (objectid > max_key->objectid)
1537 break;
1538
1539 inode = find_next_inode(root, objectid);
1540 if (!inode)
1541 break;
1542 ino = btrfs_ino(BTRFS_I(inode));
1543
1544 if (ino > max_key->objectid) {
1545 iput(inode);
1546 break;
1547 }
1548
1549 objectid = ino + 1;
1550 if (!S_ISREG(inode->i_mode))
1551 continue;
1552
1553 if (unlikely(min_key->objectid == ino)) {
1554 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1555 continue;
1556 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1557 start = 0;
1558 else {
1559 start = min_key->offset;
1560 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
1561 }
1562 } else {
1563 start = 0;
1564 }
1565
1566 if (unlikely(max_key->objectid == ino)) {
1567 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1568 continue;
1569 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1570 end = (u64)-1;
1571 } else {
1572 if (max_key->offset == 0)
1573 continue;
1574 end = max_key->offset;
1575 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1576 end--;
1577 }
1578 } else {
1579 end = (u64)-1;
1580 }
1581
1582 /* the lock_extent waits for read_folio to complete */
1583 lock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
1584 btrfs_drop_extent_map_range(BTRFS_I(inode), start, end, true);
1585 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
1586 }
1587 return 0;
1588}
1589
1590static int find_next_key(struct btrfs_path *path, int level,
1591 struct btrfs_key *key)
1592
1593{
1594 while (level < BTRFS_MAX_LEVEL) {
1595 if (!path->nodes[level])
1596 break;
1597 if (path->slots[level] + 1 <
1598 btrfs_header_nritems(path->nodes[level])) {
1599 btrfs_node_key_to_cpu(path->nodes[level], key,
1600 path->slots[level] + 1);
1601 return 0;
1602 }
1603 level++;
1604 }
1605 return 1;
1606}
1607
1608/*
1609 * Insert current subvolume into reloc_control::dirty_subvol_roots
1610 */
1611static int insert_dirty_subvol(struct btrfs_trans_handle *trans,
1612 struct reloc_control *rc,
1613 struct btrfs_root *root)
1614{
1615 struct btrfs_root *reloc_root = root->reloc_root;
1616 struct btrfs_root_item *reloc_root_item;
1617 int ret;
1618
1619 /* @root must be a subvolume tree root with a valid reloc tree */
1620 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1621 ASSERT(reloc_root);
1622
1623 reloc_root_item = &reloc_root->root_item;
1624 memset(&reloc_root_item->drop_progress, 0,
1625 sizeof(reloc_root_item->drop_progress));
1626 btrfs_set_root_drop_level(reloc_root_item, 0);
1627 btrfs_set_root_refs(reloc_root_item, 0);
1628 ret = btrfs_update_reloc_root(trans, root);
1629 if (ret)
1630 return ret;
1631
1632 if (list_empty(&root->reloc_dirty_list)) {
1633 btrfs_grab_root(root);
1634 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
1635 }
1636
1637 return 0;
1638}
1639
1640static int clean_dirty_subvols(struct reloc_control *rc)
1641{
1642 struct btrfs_root *root;
1643 struct btrfs_root *next;
1644 int ret = 0;
1645 int ret2;
1646
1647 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
1648 reloc_dirty_list) {
1649 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1650 /* Merged subvolume, cleanup its reloc root */
1651 struct btrfs_root *reloc_root = root->reloc_root;
1652
1653 list_del_init(&root->reloc_dirty_list);
1654 root->reloc_root = NULL;
1655 /*
1656 * Need barrier to ensure clear_bit() only happens after
1657 * root->reloc_root = NULL. Pairs with have_reloc_root.
1658 */
1659 smp_wmb();
1660 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
1661 if (reloc_root) {
1662 /*
1663 * btrfs_drop_snapshot drops our ref we hold for
1664 * ->reloc_root. If it fails however we must
1665 * drop the ref ourselves.
1666 */
1667 ret2 = btrfs_drop_snapshot(reloc_root, 0, 1);
1668 if (ret2 < 0) {
1669 btrfs_put_root(reloc_root);
1670 if (!ret)
1671 ret = ret2;
1672 }
1673 }
1674 btrfs_put_root(root);
1675 } else {
1676 /* Orphan reloc tree, just clean it up */
1677 ret2 = btrfs_drop_snapshot(root, 0, 1);
1678 if (ret2 < 0) {
1679 btrfs_put_root(root);
1680 if (!ret)
1681 ret = ret2;
1682 }
1683 }
1684 }
1685 return ret;
1686}
1687
1688/*
1689 * merge the relocated tree blocks in reloc tree with corresponding
1690 * fs tree.
1691 */
1692static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1693 struct btrfs_root *root)
1694{
1695 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
1696 struct btrfs_key key;
1697 struct btrfs_key next_key;
1698 struct btrfs_trans_handle *trans = NULL;
1699 struct btrfs_root *reloc_root;
1700 struct btrfs_root_item *root_item;
1701 struct btrfs_path *path;
1702 struct extent_buffer *leaf;
1703 int reserve_level;
1704 int level;
1705 int max_level;
1706 int replaced = 0;
1707 int ret = 0;
1708 u32 min_reserved;
1709
1710 path = btrfs_alloc_path();
1711 if (!path)
1712 return -ENOMEM;
1713 path->reada = READA_FORWARD;
1714
1715 reloc_root = root->reloc_root;
1716 root_item = &reloc_root->root_item;
1717
1718 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
1719 level = btrfs_root_level(root_item);
1720 atomic_inc(&reloc_root->node->refs);
1721 path->nodes[level] = reloc_root->node;
1722 path->slots[level] = 0;
1723 } else {
1724 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
1725
1726 level = btrfs_root_drop_level(root_item);
1727 BUG_ON(level == 0);
1728 path->lowest_level = level;
1729 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
1730 path->lowest_level = 0;
1731 if (ret < 0) {
1732 btrfs_free_path(path);
1733 return ret;
1734 }
1735
1736 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
1737 path->slots[level]);
1738 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
1739
1740 btrfs_unlock_up_safe(path, 0);
1741 }
1742
1743 /*
1744 * In merge_reloc_root(), we modify the upper level pointer to swap the
1745 * tree blocks between reloc tree and subvolume tree. Thus for tree
1746 * block COW, we COW at most from level 1 to root level for each tree.
1747 *
1748 * Thus the needed metadata size is at most root_level * nodesize,
1749 * and * 2 since we have two trees to COW.
1750 */
1751 reserve_level = max_t(int, 1, btrfs_root_level(root_item));
1752 min_reserved = fs_info->nodesize * reserve_level * 2;
1753 memset(&next_key, 0, sizeof(next_key));
1754
1755 while (1) {
1756 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv,
1757 min_reserved,
1758 BTRFS_RESERVE_FLUSH_LIMIT);
1759 if (ret)
1760 goto out;
1761 trans = btrfs_start_transaction(root, 0);
1762 if (IS_ERR(trans)) {
1763 ret = PTR_ERR(trans);
1764 trans = NULL;
1765 goto out;
1766 }
1767
1768 /*
1769 * At this point we no longer have a reloc_control, so we can't
1770 * depend on btrfs_init_reloc_root to update our last_trans.
1771 *
1772 * But that's ok, we started the trans handle on our
1773 * corresponding fs_root, which means it's been added to the
1774 * dirty list. At commit time we'll still call
1775 * btrfs_update_reloc_root() and update our root item
1776 * appropriately.
1777 */
1778 reloc_root->last_trans = trans->transid;
1779 trans->block_rsv = rc->block_rsv;
1780
1781 replaced = 0;
1782 max_level = level;
1783
1784 ret = walk_down_reloc_tree(reloc_root, path, &level);
1785 if (ret < 0)
1786 goto out;
1787 if (ret > 0)
1788 break;
1789
1790 if (!find_next_key(path, level, &key) &&
1791 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
1792 ret = 0;
1793 } else {
1794 ret = replace_path(trans, rc, root, reloc_root, path,
1795 &next_key, level, max_level);
1796 }
1797 if (ret < 0)
1798 goto out;
1799 if (ret > 0) {
1800 level = ret;
1801 btrfs_node_key_to_cpu(path->nodes[level], &key,
1802 path->slots[level]);
1803 replaced = 1;
1804 }
1805
1806 ret = walk_up_reloc_tree(reloc_root, path, &level);
1807 if (ret > 0)
1808 break;
1809
1810 BUG_ON(level == 0);
1811 /*
1812 * save the merging progress in the drop_progress.
1813 * this is OK since root refs == 1 in this case.
1814 */
1815 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
1816 path->slots[level]);
1817 btrfs_set_root_drop_level(root_item, level);
1818
1819 btrfs_end_transaction_throttle(trans);
1820 trans = NULL;
1821
1822 btrfs_btree_balance_dirty(fs_info);
1823
1824 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1825 invalidate_extent_cache(root, &key, &next_key);
1826 }
1827
1828 /*
1829 * handle the case only one block in the fs tree need to be
1830 * relocated and the block is tree root.
1831 */
1832 leaf = btrfs_lock_root_node(root);
1833 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf,
1834 BTRFS_NESTING_COW);
1835 btrfs_tree_unlock(leaf);
1836 free_extent_buffer(leaf);
1837out:
1838 btrfs_free_path(path);
1839
1840 if (ret == 0) {
1841 ret = insert_dirty_subvol(trans, rc, root);
1842 if (ret)
1843 btrfs_abort_transaction(trans, ret);
1844 }
1845
1846 if (trans)
1847 btrfs_end_transaction_throttle(trans);
1848
1849 btrfs_btree_balance_dirty(fs_info);
1850
1851 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1852 invalidate_extent_cache(root, &key, &next_key);
1853
1854 return ret;
1855}
1856
1857static noinline_for_stack
1858int prepare_to_merge(struct reloc_control *rc, int err)
1859{
1860 struct btrfs_root *root = rc->extent_root;
1861 struct btrfs_fs_info *fs_info = root->fs_info;
1862 struct btrfs_root *reloc_root;
1863 struct btrfs_trans_handle *trans;
1864 LIST_HEAD(reloc_roots);
1865 u64 num_bytes = 0;
1866 int ret;
1867
1868 mutex_lock(&fs_info->reloc_mutex);
1869 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
1870 rc->merging_rsv_size += rc->nodes_relocated * 2;
1871 mutex_unlock(&fs_info->reloc_mutex);
1872
1873again:
1874 if (!err) {
1875 num_bytes = rc->merging_rsv_size;
1876 ret = btrfs_block_rsv_add(fs_info, rc->block_rsv, num_bytes,
1877 BTRFS_RESERVE_FLUSH_ALL);
1878 if (ret)
1879 err = ret;
1880 }
1881
1882 trans = btrfs_join_transaction(rc->extent_root);
1883 if (IS_ERR(trans)) {
1884 if (!err)
1885 btrfs_block_rsv_release(fs_info, rc->block_rsv,
1886 num_bytes, NULL);
1887 return PTR_ERR(trans);
1888 }
1889
1890 if (!err) {
1891 if (num_bytes != rc->merging_rsv_size) {
1892 btrfs_end_transaction(trans);
1893 btrfs_block_rsv_release(fs_info, rc->block_rsv,
1894 num_bytes, NULL);
1895 goto again;
1896 }
1897 }
1898
1899 rc->merge_reloc_tree = 1;
1900
1901 while (!list_empty(&rc->reloc_roots)) {
1902 reloc_root = list_entry(rc->reloc_roots.next,
1903 struct btrfs_root, root_list);
1904 list_del_init(&reloc_root->root_list);
1905
1906 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
1907 false);
1908 if (IS_ERR(root)) {
1909 /*
1910 * Even if we have an error we need this reloc root
1911 * back on our list so we can clean up properly.
1912 */
1913 list_add(&reloc_root->root_list, &reloc_roots);
1914 btrfs_abort_transaction(trans, (int)PTR_ERR(root));
1915 if (!err)
1916 err = PTR_ERR(root);
1917 break;
1918 }
1919 ASSERT(root->reloc_root == reloc_root);
1920
1921 /*
1922 * set reference count to 1, so btrfs_recover_relocation
1923 * knows it should resumes merging
1924 */
1925 if (!err)
1926 btrfs_set_root_refs(&reloc_root->root_item, 1);
1927 ret = btrfs_update_reloc_root(trans, root);
1928
1929 /*
1930 * Even if we have an error we need this reloc root back on our
1931 * list so we can clean up properly.
1932 */
1933 list_add(&reloc_root->root_list, &reloc_roots);
1934 btrfs_put_root(root);
1935
1936 if (ret) {
1937 btrfs_abort_transaction(trans, ret);
1938 if (!err)
1939 err = ret;
1940 break;
1941 }
1942 }
1943
1944 list_splice(&reloc_roots, &rc->reloc_roots);
1945
1946 if (!err)
1947 err = btrfs_commit_transaction(trans);
1948 else
1949 btrfs_end_transaction(trans);
1950 return err;
1951}
1952
1953static noinline_for_stack
1954void free_reloc_roots(struct list_head *list)
1955{
1956 struct btrfs_root *reloc_root, *tmp;
1957
1958 list_for_each_entry_safe(reloc_root, tmp, list, root_list)
1959 __del_reloc_root(reloc_root);
1960}
1961
1962static noinline_for_stack
1963void merge_reloc_roots(struct reloc_control *rc)
1964{
1965 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
1966 struct btrfs_root *root;
1967 struct btrfs_root *reloc_root;
1968 LIST_HEAD(reloc_roots);
1969 int found = 0;
1970 int ret = 0;
1971again:
1972 root = rc->extent_root;
1973
1974 /*
1975 * this serializes us with btrfs_record_root_in_transaction,
1976 * we have to make sure nobody is in the middle of
1977 * adding their roots to the list while we are
1978 * doing this splice
1979 */
1980 mutex_lock(&fs_info->reloc_mutex);
1981 list_splice_init(&rc->reloc_roots, &reloc_roots);
1982 mutex_unlock(&fs_info->reloc_mutex);
1983
1984 while (!list_empty(&reloc_roots)) {
1985 found = 1;
1986 reloc_root = list_entry(reloc_roots.next,
1987 struct btrfs_root, root_list);
1988
1989 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
1990 false);
1991 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
1992 if (IS_ERR(root)) {
1993 /*
1994 * For recovery we read the fs roots on mount,
1995 * and if we didn't find the root then we marked
1996 * the reloc root as a garbage root. For normal
1997 * relocation obviously the root should exist in
1998 * memory. However there's no reason we can't
1999 * handle the error properly here just in case.
2000 */
2001 ASSERT(0);
2002 ret = PTR_ERR(root);
2003 goto out;
2004 }
2005 if (root->reloc_root != reloc_root) {
2006 /*
2007 * This is actually impossible without something
2008 * going really wrong (like weird race condition
2009 * or cosmic rays).
2010 */
2011 ASSERT(0);
2012 ret = -EINVAL;
2013 goto out;
2014 }
2015 ret = merge_reloc_root(rc, root);
2016 btrfs_put_root(root);
2017 if (ret) {
2018 if (list_empty(&reloc_root->root_list))
2019 list_add_tail(&reloc_root->root_list,
2020 &reloc_roots);
2021 goto out;
2022 }
2023 } else {
2024 if (!IS_ERR(root)) {
2025 if (root->reloc_root == reloc_root) {
2026 root->reloc_root = NULL;
2027 btrfs_put_root(reloc_root);
2028 }
2029 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE,
2030 &root->state);
2031 btrfs_put_root(root);
2032 }
2033
2034 list_del_init(&reloc_root->root_list);
2035 /* Don't forget to queue this reloc root for cleanup */
2036 list_add_tail(&reloc_root->reloc_dirty_list,
2037 &rc->dirty_subvol_roots);
2038 }
2039 }
2040
2041 if (found) {
2042 found = 0;
2043 goto again;
2044 }
2045out:
2046 if (ret) {
2047 btrfs_handle_fs_error(fs_info, ret, NULL);
2048 free_reloc_roots(&reloc_roots);
2049
2050 /* new reloc root may be added */
2051 mutex_lock(&fs_info->reloc_mutex);
2052 list_splice_init(&rc->reloc_roots, &reloc_roots);
2053 mutex_unlock(&fs_info->reloc_mutex);
2054 free_reloc_roots(&reloc_roots);
2055 }
2056
2057 /*
2058 * We used to have
2059 *
2060 * BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2061 *
2062 * here, but it's wrong. If we fail to start the transaction in
2063 * prepare_to_merge() we will have only 0 ref reloc roots, none of which
2064 * have actually been removed from the reloc_root_tree rb tree. This is
2065 * fine because we're bailing here, and we hold a reference on the root
2066 * for the list that holds it, so these roots will be cleaned up when we
2067 * do the reloc_dirty_list afterwards. Meanwhile the root->reloc_root
2068 * will be cleaned up on unmount.
2069 *
2070 * The remaining nodes will be cleaned up by free_reloc_control.
2071 */
2072}
2073
2074static void free_block_list(struct rb_root *blocks)
2075{
2076 struct tree_block *block;
2077 struct rb_node *rb_node;
2078 while ((rb_node = rb_first(blocks))) {
2079 block = rb_entry(rb_node, struct tree_block, rb_node);
2080 rb_erase(rb_node, blocks);
2081 kfree(block);
2082 }
2083}
2084
2085static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2086 struct btrfs_root *reloc_root)
2087{
2088 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2089 struct btrfs_root *root;
2090 int ret;
2091
2092 if (reloc_root->last_trans == trans->transid)
2093 return 0;
2094
2095 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false);
2096
2097 /*
2098 * This should succeed, since we can't have a reloc root without having
2099 * already looked up the actual root and created the reloc root for this
2100 * root.
2101 *
2102 * However if there's some sort of corruption where we have a ref to a
2103 * reloc root without a corresponding root this could return ENOENT.
2104 */
2105 if (IS_ERR(root)) {
2106 ASSERT(0);
2107 return PTR_ERR(root);
2108 }
2109 if (root->reloc_root != reloc_root) {
2110 ASSERT(0);
2111 btrfs_err(fs_info,
2112 "root %llu has two reloc roots associated with it",
2113 reloc_root->root_key.offset);
2114 btrfs_put_root(root);
2115 return -EUCLEAN;
2116 }
2117 ret = btrfs_record_root_in_trans(trans, root);
2118 btrfs_put_root(root);
2119
2120 return ret;
2121}
2122
2123static noinline_for_stack
2124struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2125 struct reloc_control *rc,
2126 struct btrfs_backref_node *node,
2127 struct btrfs_backref_edge *edges[])
2128{
2129 struct btrfs_backref_node *next;
2130 struct btrfs_root *root;
2131 int index = 0;
2132 int ret;
2133
2134 next = node;
2135 while (1) {
2136 cond_resched();
2137 next = walk_up_backref(next, edges, &index);
2138 root = next->root;
2139
2140 /*
2141 * If there is no root, then our references for this block are
2142 * incomplete, as we should be able to walk all the way up to a
2143 * block that is owned by a root.
2144 *
2145 * This path is only for SHAREABLE roots, so if we come upon a
2146 * non-SHAREABLE root then we have backrefs that resolve
2147 * improperly.
2148 *
2149 * Both of these cases indicate file system corruption, or a bug
2150 * in the backref walking code.
2151 */
2152 if (!root) {
2153 ASSERT(0);
2154 btrfs_err(trans->fs_info,
2155 "bytenr %llu doesn't have a backref path ending in a root",
2156 node->bytenr);
2157 return ERR_PTR(-EUCLEAN);
2158 }
2159 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
2160 ASSERT(0);
2161 btrfs_err(trans->fs_info,
2162 "bytenr %llu has multiple refs with one ending in a non-shareable root",
2163 node->bytenr);
2164 return ERR_PTR(-EUCLEAN);
2165 }
2166
2167 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2168 ret = record_reloc_root_in_trans(trans, root);
2169 if (ret)
2170 return ERR_PTR(ret);
2171 break;
2172 }
2173
2174 ret = btrfs_record_root_in_trans(trans, root);
2175 if (ret)
2176 return ERR_PTR(ret);
2177 root = root->reloc_root;
2178
2179 /*
2180 * We could have raced with another thread which failed, so
2181 * root->reloc_root may not be set, return ENOENT in this case.
2182 */
2183 if (!root)
2184 return ERR_PTR(-ENOENT);
2185
2186 if (next->new_bytenr != root->node->start) {
2187 /*
2188 * We just created the reloc root, so we shouldn't have
2189 * ->new_bytenr set and this shouldn't be in the changed
2190 * list. If it is then we have multiple roots pointing
2191 * at the same bytenr which indicates corruption, or
2192 * we've made a mistake in the backref walking code.
2193 */
2194 ASSERT(next->new_bytenr == 0);
2195 ASSERT(list_empty(&next->list));
2196 if (next->new_bytenr || !list_empty(&next->list)) {
2197 btrfs_err(trans->fs_info,
2198 "bytenr %llu possibly has multiple roots pointing at the same bytenr %llu",
2199 node->bytenr, next->bytenr);
2200 return ERR_PTR(-EUCLEAN);
2201 }
2202
2203 next->new_bytenr = root->node->start;
2204 btrfs_put_root(next->root);
2205 next->root = btrfs_grab_root(root);
2206 ASSERT(next->root);
2207 list_add_tail(&next->list,
2208 &rc->backref_cache.changed);
2209 mark_block_processed(rc, next);
2210 break;
2211 }
2212
2213 WARN_ON(1);
2214 root = NULL;
2215 next = walk_down_backref(edges, &index);
2216 if (!next || next->level <= node->level)
2217 break;
2218 }
2219 if (!root) {
2220 /*
2221 * This can happen if there's fs corruption or if there's a bug
2222 * in the backref lookup code.
2223 */
2224 ASSERT(0);
2225 return ERR_PTR(-ENOENT);
2226 }
2227
2228 next = node;
2229 /* setup backref node path for btrfs_reloc_cow_block */
2230 while (1) {
2231 rc->backref_cache.path[next->level] = next;
2232 if (--index < 0)
2233 break;
2234 next = edges[index]->node[UPPER];
2235 }
2236 return root;
2237}
2238
2239/*
2240 * Select a tree root for relocation.
2241 *
2242 * Return NULL if the block is not shareable. We should use do_relocation() in
2243 * this case.
2244 *
2245 * Return a tree root pointer if the block is shareable.
2246 * Return -ENOENT if the block is root of reloc tree.
2247 */
2248static noinline_for_stack
2249struct btrfs_root *select_one_root(struct btrfs_backref_node *node)
2250{
2251 struct btrfs_backref_node *next;
2252 struct btrfs_root *root;
2253 struct btrfs_root *fs_root = NULL;
2254 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2255 int index = 0;
2256
2257 next = node;
2258 while (1) {
2259 cond_resched();
2260 next = walk_up_backref(next, edges, &index);
2261 root = next->root;
2262
2263 /*
2264 * This can occur if we have incomplete extent refs leading all
2265 * the way up a particular path, in this case return -EUCLEAN.
2266 */
2267 if (!root)
2268 return ERR_PTR(-EUCLEAN);
2269
2270 /* No other choice for non-shareable tree */
2271 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
2272 return root;
2273
2274 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2275 fs_root = root;
2276
2277 if (next != node)
2278 return NULL;
2279
2280 next = walk_down_backref(edges, &index);
2281 if (!next || next->level <= node->level)
2282 break;
2283 }
2284
2285 if (!fs_root)
2286 return ERR_PTR(-ENOENT);
2287 return fs_root;
2288}
2289
2290static noinline_for_stack
2291u64 calcu_metadata_size(struct reloc_control *rc,
2292 struct btrfs_backref_node *node, int reserve)
2293{
2294 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2295 struct btrfs_backref_node *next = node;
2296 struct btrfs_backref_edge *edge;
2297 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2298 u64 num_bytes = 0;
2299 int index = 0;
2300
2301 BUG_ON(reserve && node->processed);
2302
2303 while (next) {
2304 cond_resched();
2305 while (1) {
2306 if (next->processed && (reserve || next != node))
2307 break;
2308
2309 num_bytes += fs_info->nodesize;
2310
2311 if (list_empty(&next->upper))
2312 break;
2313
2314 edge = list_entry(next->upper.next,
2315 struct btrfs_backref_edge, list[LOWER]);
2316 edges[index++] = edge;
2317 next = edge->node[UPPER];
2318 }
2319 next = walk_down_backref(edges, &index);
2320 }
2321 return num_bytes;
2322}
2323
2324static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2325 struct reloc_control *rc,
2326 struct btrfs_backref_node *node)
2327{
2328 struct btrfs_root *root = rc->extent_root;
2329 struct btrfs_fs_info *fs_info = root->fs_info;
2330 u64 num_bytes;
2331 int ret;
2332 u64 tmp;
2333
2334 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2335
2336 trans->block_rsv = rc->block_rsv;
2337 rc->reserved_bytes += num_bytes;
2338
2339 /*
2340 * We are under a transaction here so we can only do limited flushing.
2341 * If we get an enospc just kick back -EAGAIN so we know to drop the
2342 * transaction and try to refill when we can flush all the things.
2343 */
2344 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv, num_bytes,
2345 BTRFS_RESERVE_FLUSH_LIMIT);
2346 if (ret) {
2347 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2348 while (tmp <= rc->reserved_bytes)
2349 tmp <<= 1;
2350 /*
2351 * only one thread can access block_rsv at this point,
2352 * so we don't need hold lock to protect block_rsv.
2353 * we expand more reservation size here to allow enough
2354 * space for relocation and we will return earlier in
2355 * enospc case.
2356 */
2357 rc->block_rsv->size = tmp + fs_info->nodesize *
2358 RELOCATION_RESERVED_NODES;
2359 return -EAGAIN;
2360 }
2361
2362 return 0;
2363}
2364
2365/*
2366 * relocate a block tree, and then update pointers in upper level
2367 * blocks that reference the block to point to the new location.
2368 *
2369 * if called by link_to_upper, the block has already been relocated.
2370 * in that case this function just updates pointers.
2371 */
2372static int do_relocation(struct btrfs_trans_handle *trans,
2373 struct reloc_control *rc,
2374 struct btrfs_backref_node *node,
2375 struct btrfs_key *key,
2376 struct btrfs_path *path, int lowest)
2377{
2378 struct btrfs_backref_node *upper;
2379 struct btrfs_backref_edge *edge;
2380 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2381 struct btrfs_root *root;
2382 struct extent_buffer *eb;
2383 u32 blocksize;
2384 u64 bytenr;
2385 int slot;
2386 int ret = 0;
2387
2388 /*
2389 * If we are lowest then this is the first time we're processing this
2390 * block, and thus shouldn't have an eb associated with it yet.
2391 */
2392 ASSERT(!lowest || !node->eb);
2393
2394 path->lowest_level = node->level + 1;
2395 rc->backref_cache.path[node->level] = node;
2396 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2397 struct btrfs_ref ref = { 0 };
2398
2399 cond_resched();
2400
2401 upper = edge->node[UPPER];
2402 root = select_reloc_root(trans, rc, upper, edges);
2403 if (IS_ERR(root)) {
2404 ret = PTR_ERR(root);
2405 goto next;
2406 }
2407
2408 if (upper->eb && !upper->locked) {
2409 if (!lowest) {
2410 ret = btrfs_bin_search(upper->eb, key, &slot);
2411 if (ret < 0)
2412 goto next;
2413 BUG_ON(ret);
2414 bytenr = btrfs_node_blockptr(upper->eb, slot);
2415 if (node->eb->start == bytenr)
2416 goto next;
2417 }
2418 btrfs_backref_drop_node_buffer(upper);
2419 }
2420
2421 if (!upper->eb) {
2422 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2423 if (ret) {
2424 if (ret > 0)
2425 ret = -ENOENT;
2426
2427 btrfs_release_path(path);
2428 break;
2429 }
2430
2431 if (!upper->eb) {
2432 upper->eb = path->nodes[upper->level];
2433 path->nodes[upper->level] = NULL;
2434 } else {
2435 BUG_ON(upper->eb != path->nodes[upper->level]);
2436 }
2437
2438 upper->locked = 1;
2439 path->locks[upper->level] = 0;
2440
2441 slot = path->slots[upper->level];
2442 btrfs_release_path(path);
2443 } else {
2444 ret = btrfs_bin_search(upper->eb, key, &slot);
2445 if (ret < 0)
2446 goto next;
2447 BUG_ON(ret);
2448 }
2449
2450 bytenr = btrfs_node_blockptr(upper->eb, slot);
2451 if (lowest) {
2452 if (bytenr != node->bytenr) {
2453 btrfs_err(root->fs_info,
2454 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2455 bytenr, node->bytenr, slot,
2456 upper->eb->start);
2457 ret = -EIO;
2458 goto next;
2459 }
2460 } else {
2461 if (node->eb->start == bytenr)
2462 goto next;
2463 }
2464
2465 blocksize = root->fs_info->nodesize;
2466 eb = btrfs_read_node_slot(upper->eb, slot);
2467 if (IS_ERR(eb)) {
2468 ret = PTR_ERR(eb);
2469 goto next;
2470 }
2471 btrfs_tree_lock(eb);
2472
2473 if (!node->eb) {
2474 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2475 slot, &eb, BTRFS_NESTING_COW);
2476 btrfs_tree_unlock(eb);
2477 free_extent_buffer(eb);
2478 if (ret < 0)
2479 goto next;
2480 /*
2481 * We've just COWed this block, it should have updated
2482 * the correct backref node entry.
2483 */
2484 ASSERT(node->eb == eb);
2485 } else {
2486 btrfs_set_node_blockptr(upper->eb, slot,
2487 node->eb->start);
2488 btrfs_set_node_ptr_generation(upper->eb, slot,
2489 trans->transid);
2490 btrfs_mark_buffer_dirty(upper->eb);
2491
2492 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2493 node->eb->start, blocksize,
2494 upper->eb->start);
2495 btrfs_init_tree_ref(&ref, node->level,
2496 btrfs_header_owner(upper->eb),
2497 root->root_key.objectid, false);
2498 ret = btrfs_inc_extent_ref(trans, &ref);
2499 if (!ret)
2500 ret = btrfs_drop_subtree(trans, root, eb,
2501 upper->eb);
2502 if (ret)
2503 btrfs_abort_transaction(trans, ret);
2504 }
2505next:
2506 if (!upper->pending)
2507 btrfs_backref_drop_node_buffer(upper);
2508 else
2509 btrfs_backref_unlock_node_buffer(upper);
2510 if (ret)
2511 break;
2512 }
2513
2514 if (!ret && node->pending) {
2515 btrfs_backref_drop_node_buffer(node);
2516 list_move_tail(&node->list, &rc->backref_cache.changed);
2517 node->pending = 0;
2518 }
2519
2520 path->lowest_level = 0;
2521
2522 /*
2523 * We should have allocated all of our space in the block rsv and thus
2524 * shouldn't ENOSPC.
2525 */
2526 ASSERT(ret != -ENOSPC);
2527 return ret;
2528}
2529
2530static int link_to_upper(struct btrfs_trans_handle *trans,
2531 struct reloc_control *rc,
2532 struct btrfs_backref_node *node,
2533 struct btrfs_path *path)
2534{
2535 struct btrfs_key key;
2536
2537 btrfs_node_key_to_cpu(node->eb, &key, 0);
2538 return do_relocation(trans, rc, node, &key, path, 0);
2539}
2540
2541static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2542 struct reloc_control *rc,
2543 struct btrfs_path *path, int err)
2544{
2545 LIST_HEAD(list);
2546 struct btrfs_backref_cache *cache = &rc->backref_cache;
2547 struct btrfs_backref_node *node;
2548 int level;
2549 int ret;
2550
2551 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2552 while (!list_empty(&cache->pending[level])) {
2553 node = list_entry(cache->pending[level].next,
2554 struct btrfs_backref_node, list);
2555 list_move_tail(&node->list, &list);
2556 BUG_ON(!node->pending);
2557
2558 if (!err) {
2559 ret = link_to_upper(trans, rc, node, path);
2560 if (ret < 0)
2561 err = ret;
2562 }
2563 }
2564 list_splice_init(&list, &cache->pending[level]);
2565 }
2566 return err;
2567}
2568
2569/*
2570 * mark a block and all blocks directly/indirectly reference the block
2571 * as processed.
2572 */
2573static void update_processed_blocks(struct reloc_control *rc,
2574 struct btrfs_backref_node *node)
2575{
2576 struct btrfs_backref_node *next = node;
2577 struct btrfs_backref_edge *edge;
2578 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2579 int index = 0;
2580
2581 while (next) {
2582 cond_resched();
2583 while (1) {
2584 if (next->processed)
2585 break;
2586
2587 mark_block_processed(rc, next);
2588
2589 if (list_empty(&next->upper))
2590 break;
2591
2592 edge = list_entry(next->upper.next,
2593 struct btrfs_backref_edge, list[LOWER]);
2594 edges[index++] = edge;
2595 next = edge->node[UPPER];
2596 }
2597 next = walk_down_backref(edges, &index);
2598 }
2599}
2600
2601static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2602{
2603 u32 blocksize = rc->extent_root->fs_info->nodesize;
2604
2605 if (test_range_bit(&rc->processed_blocks, bytenr,
2606 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2607 return 1;
2608 return 0;
2609}
2610
2611static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2612 struct tree_block *block)
2613{
2614 struct btrfs_tree_parent_check check = {
2615 .level = block->level,
2616 .owner_root = block->owner,
2617 .transid = block->key.offset
2618 };
2619 struct extent_buffer *eb;
2620
2621 eb = read_tree_block(fs_info, block->bytenr, &check);
2622 if (IS_ERR(eb))
2623 return PTR_ERR(eb);
2624 if (!extent_buffer_uptodate(eb)) {
2625 free_extent_buffer(eb);
2626 return -EIO;
2627 }
2628 if (block->level == 0)
2629 btrfs_item_key_to_cpu(eb, &block->key, 0);
2630 else
2631 btrfs_node_key_to_cpu(eb, &block->key, 0);
2632 free_extent_buffer(eb);
2633 block->key_ready = 1;
2634 return 0;
2635}
2636
2637/*
2638 * helper function to relocate a tree block
2639 */
2640static int relocate_tree_block(struct btrfs_trans_handle *trans,
2641 struct reloc_control *rc,
2642 struct btrfs_backref_node *node,
2643 struct btrfs_key *key,
2644 struct btrfs_path *path)
2645{
2646 struct btrfs_root *root;
2647 int ret = 0;
2648
2649 if (!node)
2650 return 0;
2651
2652 /*
2653 * If we fail here we want to drop our backref_node because we are going
2654 * to start over and regenerate the tree for it.
2655 */
2656 ret = reserve_metadata_space(trans, rc, node);
2657 if (ret)
2658 goto out;
2659
2660 BUG_ON(node->processed);
2661 root = select_one_root(node);
2662 if (IS_ERR(root)) {
2663 ret = PTR_ERR(root);
2664
2665 /* See explanation in select_one_root for the -EUCLEAN case. */
2666 ASSERT(ret == -ENOENT);
2667 if (ret == -ENOENT) {
2668 ret = 0;
2669 update_processed_blocks(rc, node);
2670 }
2671 goto out;
2672 }
2673
2674 if (root) {
2675 if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
2676 /*
2677 * This block was the root block of a root, and this is
2678 * the first time we're processing the block and thus it
2679 * should not have had the ->new_bytenr modified and
2680 * should have not been included on the changed list.
2681 *
2682 * However in the case of corruption we could have
2683 * multiple refs pointing to the same block improperly,
2684 * and thus we would trip over these checks. ASSERT()
2685 * for the developer case, because it could indicate a
2686 * bug in the backref code, however error out for a
2687 * normal user in the case of corruption.
2688 */
2689 ASSERT(node->new_bytenr == 0);
2690 ASSERT(list_empty(&node->list));
2691 if (node->new_bytenr || !list_empty(&node->list)) {
2692 btrfs_err(root->fs_info,
2693 "bytenr %llu has improper references to it",
2694 node->bytenr);
2695 ret = -EUCLEAN;
2696 goto out;
2697 }
2698 ret = btrfs_record_root_in_trans(trans, root);
2699 if (ret)
2700 goto out;
2701 /*
2702 * Another thread could have failed, need to check if we
2703 * have reloc_root actually set.
2704 */
2705 if (!root->reloc_root) {
2706 ret = -ENOENT;
2707 goto out;
2708 }
2709 root = root->reloc_root;
2710 node->new_bytenr = root->node->start;
2711 btrfs_put_root(node->root);
2712 node->root = btrfs_grab_root(root);
2713 ASSERT(node->root);
2714 list_add_tail(&node->list, &rc->backref_cache.changed);
2715 } else {
2716 path->lowest_level = node->level;
2717 if (root == root->fs_info->chunk_root)
2718 btrfs_reserve_chunk_metadata(trans, false);
2719 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2720 btrfs_release_path(path);
2721 if (root == root->fs_info->chunk_root)
2722 btrfs_trans_release_chunk_metadata(trans);
2723 if (ret > 0)
2724 ret = 0;
2725 }
2726 if (!ret)
2727 update_processed_blocks(rc, node);
2728 } else {
2729 ret = do_relocation(trans, rc, node, key, path, 1);
2730 }
2731out:
2732 if (ret || node->level == 0 || node->cowonly)
2733 btrfs_backref_cleanup_node(&rc->backref_cache, node);
2734 return ret;
2735}
2736
2737/*
2738 * relocate a list of blocks
2739 */
2740static noinline_for_stack
2741int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2742 struct reloc_control *rc, struct rb_root *blocks)
2743{
2744 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2745 struct btrfs_backref_node *node;
2746 struct btrfs_path *path;
2747 struct tree_block *block;
2748 struct tree_block *next;
2749 int ret;
2750 int err = 0;
2751
2752 path = btrfs_alloc_path();
2753 if (!path) {
2754 err = -ENOMEM;
2755 goto out_free_blocks;
2756 }
2757
2758 /* Kick in readahead for tree blocks with missing keys */
2759 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2760 if (!block->key_ready)
2761 btrfs_readahead_tree_block(fs_info, block->bytenr,
2762 block->owner, 0,
2763 block->level);
2764 }
2765
2766 /* Get first keys */
2767 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2768 if (!block->key_ready) {
2769 err = get_tree_block_key(fs_info, block);
2770 if (err)
2771 goto out_free_path;
2772 }
2773 }
2774
2775 /* Do tree relocation */
2776 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2777 node = build_backref_tree(rc, &block->key,
2778 block->level, block->bytenr);
2779 if (IS_ERR(node)) {
2780 err = PTR_ERR(node);
2781 goto out;
2782 }
2783
2784 ret = relocate_tree_block(trans, rc, node, &block->key,
2785 path);
2786 if (ret < 0) {
2787 err = ret;
2788 break;
2789 }
2790 }
2791out:
2792 err = finish_pending_nodes(trans, rc, path, err);
2793
2794out_free_path:
2795 btrfs_free_path(path);
2796out_free_blocks:
2797 free_block_list(blocks);
2798 return err;
2799}
2800
2801static noinline_for_stack int prealloc_file_extent_cluster(
2802 struct btrfs_inode *inode,
2803 struct file_extent_cluster *cluster)
2804{
2805 u64 alloc_hint = 0;
2806 u64 start;
2807 u64 end;
2808 u64 offset = inode->index_cnt;
2809 u64 num_bytes;
2810 int nr;
2811 int ret = 0;
2812 u64 i_size = i_size_read(&inode->vfs_inode);
2813 u64 prealloc_start = cluster->start - offset;
2814 u64 prealloc_end = cluster->end - offset;
2815 u64 cur_offset = prealloc_start;
2816
2817 /*
2818 * For subpage case, previous i_size may not be aligned to PAGE_SIZE.
2819 * This means the range [i_size, PAGE_END + 1) is filled with zeros by
2820 * btrfs_do_readpage() call of previously relocated file cluster.
2821 *
2822 * If the current cluster starts in the above range, btrfs_do_readpage()
2823 * will skip the read, and relocate_one_page() will later writeback
2824 * the padding zeros as new data, causing data corruption.
2825 *
2826 * Here we have to manually invalidate the range (i_size, PAGE_END + 1).
2827 */
2828 if (!IS_ALIGNED(i_size, PAGE_SIZE)) {
2829 struct address_space *mapping = inode->vfs_inode.i_mapping;
2830 struct btrfs_fs_info *fs_info = inode->root->fs_info;
2831 const u32 sectorsize = fs_info->sectorsize;
2832 struct page *page;
2833
2834 ASSERT(sectorsize < PAGE_SIZE);
2835 ASSERT(IS_ALIGNED(i_size, sectorsize));
2836
2837 /*
2838 * Subpage can't handle page with DIRTY but without UPTODATE
2839 * bit as it can lead to the following deadlock:
2840 *
2841 * btrfs_read_folio()
2842 * | Page already *locked*
2843 * |- btrfs_lock_and_flush_ordered_range()
2844 * |- btrfs_start_ordered_extent()
2845 * |- extent_write_cache_pages()
2846 * |- lock_page()
2847 * We try to lock the page we already hold.
2848 *
2849 * Here we just writeback the whole data reloc inode, so that
2850 * we will be ensured to have no dirty range in the page, and
2851 * are safe to clear the uptodate bits.
2852 *
2853 * This shouldn't cause too much overhead, as we need to write
2854 * the data back anyway.
2855 */
2856 ret = filemap_write_and_wait(mapping);
2857 if (ret < 0)
2858 return ret;
2859
2860 clear_extent_bits(&inode->io_tree, i_size,
2861 round_up(i_size, PAGE_SIZE) - 1,
2862 EXTENT_UPTODATE);
2863 page = find_lock_page(mapping, i_size >> PAGE_SHIFT);
2864 /*
2865 * If page is freed we don't need to do anything then, as we
2866 * will re-read the whole page anyway.
2867 */
2868 if (page) {
2869 btrfs_subpage_clear_uptodate(fs_info, page, i_size,
2870 round_up(i_size, PAGE_SIZE) - i_size);
2871 unlock_page(page);
2872 put_page(page);
2873 }
2874 }
2875
2876 BUG_ON(cluster->start != cluster->boundary[0]);
2877 ret = btrfs_alloc_data_chunk_ondemand(inode,
2878 prealloc_end + 1 - prealloc_start);
2879 if (ret)
2880 return ret;
2881
2882 btrfs_inode_lock(inode, 0);
2883 for (nr = 0; nr < cluster->nr; nr++) {
2884 struct extent_state *cached_state = NULL;
2885
2886 start = cluster->boundary[nr] - offset;
2887 if (nr + 1 < cluster->nr)
2888 end = cluster->boundary[nr + 1] - 1 - offset;
2889 else
2890 end = cluster->end - offset;
2891
2892 lock_extent(&inode->io_tree, start, end, &cached_state);
2893 num_bytes = end + 1 - start;
2894 ret = btrfs_prealloc_file_range(&inode->vfs_inode, 0, start,
2895 num_bytes, num_bytes,
2896 end + 1, &alloc_hint);
2897 cur_offset = end + 1;
2898 unlock_extent(&inode->io_tree, start, end, &cached_state);
2899 if (ret)
2900 break;
2901 }
2902 btrfs_inode_unlock(inode, 0);
2903
2904 if (cur_offset < prealloc_end)
2905 btrfs_free_reserved_data_space_noquota(inode->root->fs_info,
2906 prealloc_end + 1 - cur_offset);
2907 return ret;
2908}
2909
2910static noinline_for_stack int setup_relocation_extent_mapping(struct inode *inode,
2911 u64 start, u64 end, u64 block_start)
2912{
2913 struct extent_map *em;
2914 struct extent_state *cached_state = NULL;
2915 int ret = 0;
2916
2917 em = alloc_extent_map();
2918 if (!em)
2919 return -ENOMEM;
2920
2921 em->start = start;
2922 em->len = end + 1 - start;
2923 em->block_len = em->len;
2924 em->block_start = block_start;
2925 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2926
2927 lock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
2928 ret = btrfs_replace_extent_map_range(BTRFS_I(inode), em, false);
2929 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
2930 free_extent_map(em);
2931
2932 return ret;
2933}
2934
2935/*
2936 * Allow error injection to test balance/relocation cancellation
2937 */
2938noinline int btrfs_should_cancel_balance(struct btrfs_fs_info *fs_info)
2939{
2940 return atomic_read(&fs_info->balance_cancel_req) ||
2941 atomic_read(&fs_info->reloc_cancel_req) ||
2942 fatal_signal_pending(current);
2943}
2944ALLOW_ERROR_INJECTION(btrfs_should_cancel_balance, TRUE);
2945
2946static u64 get_cluster_boundary_end(struct file_extent_cluster *cluster,
2947 int cluster_nr)
2948{
2949 /* Last extent, use cluster end directly */
2950 if (cluster_nr >= cluster->nr - 1)
2951 return cluster->end;
2952
2953 /* Use next boundary start*/
2954 return cluster->boundary[cluster_nr + 1] - 1;
2955}
2956
2957static int relocate_one_page(struct inode *inode, struct file_ra_state *ra,
2958 struct file_extent_cluster *cluster,
2959 int *cluster_nr, unsigned long page_index)
2960{
2961 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2962 u64 offset = BTRFS_I(inode)->index_cnt;
2963 const unsigned long last_index = (cluster->end - offset) >> PAGE_SHIFT;
2964 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
2965 struct page *page;
2966 u64 page_start;
2967 u64 page_end;
2968 u64 cur;
2969 int ret;
2970
2971 ASSERT(page_index <= last_index);
2972 page = find_lock_page(inode->i_mapping, page_index);
2973 if (!page) {
2974 page_cache_sync_readahead(inode->i_mapping, ra, NULL,
2975 page_index, last_index + 1 - page_index);
2976 page = find_or_create_page(inode->i_mapping, page_index, mask);
2977 if (!page)
2978 return -ENOMEM;
2979 }
2980 ret = set_page_extent_mapped(page);
2981 if (ret < 0)
2982 goto release_page;
2983
2984 if (PageReadahead(page))
2985 page_cache_async_readahead(inode->i_mapping, ra, NULL,
2986 page_folio(page), page_index,
2987 last_index + 1 - page_index);
2988
2989 if (!PageUptodate(page)) {
2990 btrfs_read_folio(NULL, page_folio(page));
2991 lock_page(page);
2992 if (!PageUptodate(page)) {
2993 ret = -EIO;
2994 goto release_page;
2995 }
2996 }
2997
2998 page_start = page_offset(page);
2999 page_end = page_start + PAGE_SIZE - 1;
3000
3001 /*
3002 * Start from the cluster, as for subpage case, the cluster can start
3003 * inside the page.
3004 */
3005 cur = max(page_start, cluster->boundary[*cluster_nr] - offset);
3006 while (cur <= page_end) {
3007 struct extent_state *cached_state = NULL;
3008 u64 extent_start = cluster->boundary[*cluster_nr] - offset;
3009 u64 extent_end = get_cluster_boundary_end(cluster,
3010 *cluster_nr) - offset;
3011 u64 clamped_start = max(page_start, extent_start);
3012 u64 clamped_end = min(page_end, extent_end);
3013 u32 clamped_len = clamped_end + 1 - clamped_start;
3014
3015 /* Reserve metadata for this range */
3016 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3017 clamped_len, clamped_len,
3018 false);
3019 if (ret)
3020 goto release_page;
3021
3022 /* Mark the range delalloc and dirty for later writeback */
3023 lock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end,
3024 &cached_state);
3025 ret = btrfs_set_extent_delalloc(BTRFS_I(inode), clamped_start,
3026 clamped_end, 0, &cached_state);
3027 if (ret) {
3028 clear_extent_bit(&BTRFS_I(inode)->io_tree,
3029 clamped_start, clamped_end,
3030 EXTENT_LOCKED | EXTENT_BOUNDARY,
3031 &cached_state);
3032 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3033 clamped_len, true);
3034 btrfs_delalloc_release_extents(BTRFS_I(inode),
3035 clamped_len);
3036 goto release_page;
3037 }
3038 btrfs_page_set_dirty(fs_info, page, clamped_start, clamped_len);
3039
3040 /*
3041 * Set the boundary if it's inside the page.
3042 * Data relocation requires the destination extents to have the
3043 * same size as the source.
3044 * EXTENT_BOUNDARY bit prevents current extent from being merged
3045 * with previous extent.
3046 */
3047 if (in_range(cluster->boundary[*cluster_nr] - offset,
3048 page_start, PAGE_SIZE)) {
3049 u64 boundary_start = cluster->boundary[*cluster_nr] -
3050 offset;
3051 u64 boundary_end = boundary_start +
3052 fs_info->sectorsize - 1;
3053
3054 set_extent_bits(&BTRFS_I(inode)->io_tree,
3055 boundary_start, boundary_end,
3056 EXTENT_BOUNDARY);
3057 }
3058 unlock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end,
3059 &cached_state);
3060 btrfs_delalloc_release_extents(BTRFS_I(inode), clamped_len);
3061 cur += clamped_len;
3062
3063 /* Crossed extent end, go to next extent */
3064 if (cur >= extent_end) {
3065 (*cluster_nr)++;
3066 /* Just finished the last extent of the cluster, exit. */
3067 if (*cluster_nr >= cluster->nr)
3068 break;
3069 }
3070 }
3071 unlock_page(page);
3072 put_page(page);
3073
3074 balance_dirty_pages_ratelimited(inode->i_mapping);
3075 btrfs_throttle(fs_info);
3076 if (btrfs_should_cancel_balance(fs_info))
3077 ret = -ECANCELED;
3078 return ret;
3079
3080release_page:
3081 unlock_page(page);
3082 put_page(page);
3083 return ret;
3084}
3085
3086static int relocate_file_extent_cluster(struct inode *inode,
3087 struct file_extent_cluster *cluster)
3088{
3089 u64 offset = BTRFS_I(inode)->index_cnt;
3090 unsigned long index;
3091 unsigned long last_index;
3092 struct file_ra_state *ra;
3093 int cluster_nr = 0;
3094 int ret = 0;
3095
3096 if (!cluster->nr)
3097 return 0;
3098
3099 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3100 if (!ra)
3101 return -ENOMEM;
3102
3103 ret = prealloc_file_extent_cluster(BTRFS_I(inode), cluster);
3104 if (ret)
3105 goto out;
3106
3107 file_ra_state_init(ra, inode->i_mapping);
3108
3109 ret = setup_relocation_extent_mapping(inode, cluster->start - offset,
3110 cluster->end - offset, cluster->start);
3111 if (ret)
3112 goto out;
3113
3114 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3115 for (index = (cluster->start - offset) >> PAGE_SHIFT;
3116 index <= last_index && !ret; index++)
3117 ret = relocate_one_page(inode, ra, cluster, &cluster_nr, index);
3118 if (ret == 0)
3119 WARN_ON(cluster_nr != cluster->nr);
3120out:
3121 kfree(ra);
3122 return ret;
3123}
3124
3125static noinline_for_stack
3126int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3127 struct file_extent_cluster *cluster)
3128{
3129 int ret;
3130
3131 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3132 ret = relocate_file_extent_cluster(inode, cluster);
3133 if (ret)
3134 return ret;
3135 cluster->nr = 0;
3136 }
3137
3138 if (!cluster->nr)
3139 cluster->start = extent_key->objectid;
3140 else
3141 BUG_ON(cluster->nr >= MAX_EXTENTS);
3142 cluster->end = extent_key->objectid + extent_key->offset - 1;
3143 cluster->boundary[cluster->nr] = extent_key->objectid;
3144 cluster->nr++;
3145
3146 if (cluster->nr >= MAX_EXTENTS) {
3147 ret = relocate_file_extent_cluster(inode, cluster);
3148 if (ret)
3149 return ret;
3150 cluster->nr = 0;
3151 }
3152 return 0;
3153}
3154
3155/*
3156 * helper to add a tree block to the list.
3157 * the major work is getting the generation and level of the block
3158 */
3159static int add_tree_block(struct reloc_control *rc,
3160 struct btrfs_key *extent_key,
3161 struct btrfs_path *path,
3162 struct rb_root *blocks)
3163{
3164 struct extent_buffer *eb;
3165 struct btrfs_extent_item *ei;
3166 struct btrfs_tree_block_info *bi;
3167 struct tree_block *block;
3168 struct rb_node *rb_node;
3169 u32 item_size;
3170 int level = -1;
3171 u64 generation;
3172 u64 owner = 0;
3173
3174 eb = path->nodes[0];
3175 item_size = btrfs_item_size(eb, path->slots[0]);
3176
3177 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3178 item_size >= sizeof(*ei) + sizeof(*bi)) {
3179 unsigned long ptr = 0, end;
3180
3181 ei = btrfs_item_ptr(eb, path->slots[0],
3182 struct btrfs_extent_item);
3183 end = (unsigned long)ei + item_size;
3184 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3185 bi = (struct btrfs_tree_block_info *)(ei + 1);
3186 level = btrfs_tree_block_level(eb, bi);
3187 ptr = (unsigned long)(bi + 1);
3188 } else {
3189 level = (int)extent_key->offset;
3190 ptr = (unsigned long)(ei + 1);
3191 }
3192 generation = btrfs_extent_generation(eb, ei);
3193
3194 /*
3195 * We're reading random blocks without knowing their owner ahead
3196 * of time. This is ok most of the time, as all reloc roots and
3197 * fs roots have the same lock type. However normal trees do
3198 * not, and the only way to know ahead of time is to read the
3199 * inline ref offset. We know it's an fs root if
3200 *
3201 * 1. There's more than one ref.
3202 * 2. There's a SHARED_DATA_REF_KEY set.
3203 * 3. FULL_BACKREF is set on the flags.
3204 *
3205 * Otherwise it's safe to assume that the ref offset == the
3206 * owner of this block, so we can use that when calling
3207 * read_tree_block.
3208 */
3209 if (btrfs_extent_refs(eb, ei) == 1 &&
3210 !(btrfs_extent_flags(eb, ei) &
3211 BTRFS_BLOCK_FLAG_FULL_BACKREF) &&
3212 ptr < end) {
3213 struct btrfs_extent_inline_ref *iref;
3214 int type;
3215
3216 iref = (struct btrfs_extent_inline_ref *)ptr;
3217 type = btrfs_get_extent_inline_ref_type(eb, iref,
3218 BTRFS_REF_TYPE_BLOCK);
3219 if (type == BTRFS_REF_TYPE_INVALID)
3220 return -EINVAL;
3221 if (type == BTRFS_TREE_BLOCK_REF_KEY)
3222 owner = btrfs_extent_inline_ref_offset(eb, iref);
3223 }
3224 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3225 btrfs_print_v0_err(eb->fs_info);
3226 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3227 return -EINVAL;
3228 } else {
3229 BUG();
3230 }
3231
3232 btrfs_release_path(path);
3233
3234 BUG_ON(level == -1);
3235
3236 block = kmalloc(sizeof(*block), GFP_NOFS);
3237 if (!block)
3238 return -ENOMEM;
3239
3240 block->bytenr = extent_key->objectid;
3241 block->key.objectid = rc->extent_root->fs_info->nodesize;
3242 block->key.offset = generation;
3243 block->level = level;
3244 block->key_ready = 0;
3245 block->owner = owner;
3246
3247 rb_node = rb_simple_insert(blocks, block->bytenr, &block->rb_node);
3248 if (rb_node)
3249 btrfs_backref_panic(rc->extent_root->fs_info, block->bytenr,
3250 -EEXIST);
3251
3252 return 0;
3253}
3254
3255/*
3256 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3257 */
3258static int __add_tree_block(struct reloc_control *rc,
3259 u64 bytenr, u32 blocksize,
3260 struct rb_root *blocks)
3261{
3262 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3263 struct btrfs_path *path;
3264 struct btrfs_key key;
3265 int ret;
3266 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3267
3268 if (tree_block_processed(bytenr, rc))
3269 return 0;
3270
3271 if (rb_simple_search(blocks, bytenr))
3272 return 0;
3273
3274 path = btrfs_alloc_path();
3275 if (!path)
3276 return -ENOMEM;
3277again:
3278 key.objectid = bytenr;
3279 if (skinny) {
3280 key.type = BTRFS_METADATA_ITEM_KEY;
3281 key.offset = (u64)-1;
3282 } else {
3283 key.type = BTRFS_EXTENT_ITEM_KEY;
3284 key.offset = blocksize;
3285 }
3286
3287 path->search_commit_root = 1;
3288 path->skip_locking = 1;
3289 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3290 if (ret < 0)
3291 goto out;
3292
3293 if (ret > 0 && skinny) {
3294 if (path->slots[0]) {
3295 path->slots[0]--;
3296 btrfs_item_key_to_cpu(path->nodes[0], &key,
3297 path->slots[0]);
3298 if (key.objectid == bytenr &&
3299 (key.type == BTRFS_METADATA_ITEM_KEY ||
3300 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3301 key.offset == blocksize)))
3302 ret = 0;
3303 }
3304
3305 if (ret) {
3306 skinny = false;
3307 btrfs_release_path(path);
3308 goto again;
3309 }
3310 }
3311 if (ret) {
3312 ASSERT(ret == 1);
3313 btrfs_print_leaf(path->nodes[0]);
3314 btrfs_err(fs_info,
3315 "tree block extent item (%llu) is not found in extent tree",
3316 bytenr);
3317 WARN_ON(1);
3318 ret = -EINVAL;
3319 goto out;
3320 }
3321
3322 ret = add_tree_block(rc, &key, path, blocks);
3323out:
3324 btrfs_free_path(path);
3325 return ret;
3326}
3327
3328static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3329 struct btrfs_block_group *block_group,
3330 struct inode *inode,
3331 u64 ino)
3332{
3333 struct btrfs_root *root = fs_info->tree_root;
3334 struct btrfs_trans_handle *trans;
3335 int ret = 0;
3336
3337 if (inode)
3338 goto truncate;
3339
3340 inode = btrfs_iget(fs_info->sb, ino, root);
3341 if (IS_ERR(inode))
3342 return -ENOENT;
3343
3344truncate:
3345 ret = btrfs_check_trunc_cache_free_space(fs_info,
3346 &fs_info->global_block_rsv);
3347 if (ret)
3348 goto out;
3349
3350 trans = btrfs_join_transaction(root);
3351 if (IS_ERR(trans)) {
3352 ret = PTR_ERR(trans);
3353 goto out;
3354 }
3355
3356 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3357
3358 btrfs_end_transaction(trans);
3359 btrfs_btree_balance_dirty(fs_info);
3360out:
3361 iput(inode);
3362 return ret;
3363}
3364
3365/*
3366 * Locate the free space cache EXTENT_DATA in root tree leaf and delete the
3367 * cache inode, to avoid free space cache data extent blocking data relocation.
3368 */
3369static int delete_v1_space_cache(struct extent_buffer *leaf,
3370 struct btrfs_block_group *block_group,
3371 u64 data_bytenr)
3372{
3373 u64 space_cache_ino;
3374 struct btrfs_file_extent_item *ei;
3375 struct btrfs_key key;
3376 bool found = false;
3377 int i;
3378 int ret;
3379
3380 if (btrfs_header_owner(leaf) != BTRFS_ROOT_TREE_OBJECTID)
3381 return 0;
3382
3383 for (i = 0; i < btrfs_header_nritems(leaf); i++) {
3384 u8 type;
3385
3386 btrfs_item_key_to_cpu(leaf, &key, i);
3387 if (key.type != BTRFS_EXTENT_DATA_KEY)
3388 continue;
3389 ei = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
3390 type = btrfs_file_extent_type(leaf, ei);
3391
3392 if ((type == BTRFS_FILE_EXTENT_REG ||
3393 type == BTRFS_FILE_EXTENT_PREALLOC) &&
3394 btrfs_file_extent_disk_bytenr(leaf, ei) == data_bytenr) {
3395 found = true;
3396 space_cache_ino = key.objectid;
3397 break;
3398 }
3399 }
3400 if (!found)
3401 return -ENOENT;
3402 ret = delete_block_group_cache(leaf->fs_info, block_group, NULL,
3403 space_cache_ino);
3404 return ret;
3405}
3406
3407/*
3408 * helper to find all tree blocks that reference a given data extent
3409 */
3410static noinline_for_stack
3411int add_data_references(struct reloc_control *rc,
3412 struct btrfs_key *extent_key,
3413 struct btrfs_path *path,
3414 struct rb_root *blocks)
3415{
3416 struct btrfs_backref_walk_ctx ctx = { 0 };
3417 struct ulist_iterator leaf_uiter;
3418 struct ulist_node *ref_node = NULL;
3419 const u32 blocksize = rc->extent_root->fs_info->nodesize;
3420 int ret = 0;
3421
3422 btrfs_release_path(path);
3423
3424 ctx.bytenr = extent_key->objectid;
3425 ctx.ignore_extent_item_pos = true;
3426 ctx.fs_info = rc->extent_root->fs_info;
3427
3428 ret = btrfs_find_all_leafs(&ctx);
3429 if (ret < 0)
3430 return ret;
3431
3432 ULIST_ITER_INIT(&leaf_uiter);
3433 while ((ref_node = ulist_next(ctx.refs, &leaf_uiter))) {
3434 struct btrfs_tree_parent_check check = { 0 };
3435 struct extent_buffer *eb;
3436
3437 eb = read_tree_block(ctx.fs_info, ref_node->val, &check);
3438 if (IS_ERR(eb)) {
3439 ret = PTR_ERR(eb);
3440 break;
3441 }
3442 ret = delete_v1_space_cache(eb, rc->block_group,
3443 extent_key->objectid);
3444 free_extent_buffer(eb);
3445 if (ret < 0)
3446 break;
3447 ret = __add_tree_block(rc, ref_node->val, blocksize, blocks);
3448 if (ret < 0)
3449 break;
3450 }
3451 if (ret < 0)
3452 free_block_list(blocks);
3453 ulist_free(ctx.refs);
3454 return ret;
3455}
3456
3457/*
3458 * helper to find next unprocessed extent
3459 */
3460static noinline_for_stack
3461int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3462 struct btrfs_key *extent_key)
3463{
3464 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3465 struct btrfs_key key;
3466 struct extent_buffer *leaf;
3467 u64 start, end, last;
3468 int ret;
3469
3470 last = rc->block_group->start + rc->block_group->length;
3471 while (1) {
3472 cond_resched();
3473 if (rc->search_start >= last) {
3474 ret = 1;
3475 break;
3476 }
3477
3478 key.objectid = rc->search_start;
3479 key.type = BTRFS_EXTENT_ITEM_KEY;
3480 key.offset = 0;
3481
3482 path->search_commit_root = 1;
3483 path->skip_locking = 1;
3484 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3485 0, 0);
3486 if (ret < 0)
3487 break;
3488next:
3489 leaf = path->nodes[0];
3490 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3491 ret = btrfs_next_leaf(rc->extent_root, path);
3492 if (ret != 0)
3493 break;
3494 leaf = path->nodes[0];
3495 }
3496
3497 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3498 if (key.objectid >= last) {
3499 ret = 1;
3500 break;
3501 }
3502
3503 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3504 key.type != BTRFS_METADATA_ITEM_KEY) {
3505 path->slots[0]++;
3506 goto next;
3507 }
3508
3509 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3510 key.objectid + key.offset <= rc->search_start) {
3511 path->slots[0]++;
3512 goto next;
3513 }
3514
3515 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3516 key.objectid + fs_info->nodesize <=
3517 rc->search_start) {
3518 path->slots[0]++;
3519 goto next;
3520 }
3521
3522 ret = find_first_extent_bit(&rc->processed_blocks,
3523 key.objectid, &start, &end,
3524 EXTENT_DIRTY, NULL);
3525
3526 if (ret == 0 && start <= key.objectid) {
3527 btrfs_release_path(path);
3528 rc->search_start = end + 1;
3529 } else {
3530 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3531 rc->search_start = key.objectid + key.offset;
3532 else
3533 rc->search_start = key.objectid +
3534 fs_info->nodesize;
3535 memcpy(extent_key, &key, sizeof(key));
3536 return 0;
3537 }
3538 }
3539 btrfs_release_path(path);
3540 return ret;
3541}
3542
3543static void set_reloc_control(struct reloc_control *rc)
3544{
3545 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3546
3547 mutex_lock(&fs_info->reloc_mutex);
3548 fs_info->reloc_ctl = rc;
3549 mutex_unlock(&fs_info->reloc_mutex);
3550}
3551
3552static void unset_reloc_control(struct reloc_control *rc)
3553{
3554 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3555
3556 mutex_lock(&fs_info->reloc_mutex);
3557 fs_info->reloc_ctl = NULL;
3558 mutex_unlock(&fs_info->reloc_mutex);
3559}
3560
3561static noinline_for_stack
3562int prepare_to_relocate(struct reloc_control *rc)
3563{
3564 struct btrfs_trans_handle *trans;
3565 int ret;
3566
3567 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3568 BTRFS_BLOCK_RSV_TEMP);
3569 if (!rc->block_rsv)
3570 return -ENOMEM;
3571
3572 memset(&rc->cluster, 0, sizeof(rc->cluster));
3573 rc->search_start = rc->block_group->start;
3574 rc->extents_found = 0;
3575 rc->nodes_relocated = 0;
3576 rc->merging_rsv_size = 0;
3577 rc->reserved_bytes = 0;
3578 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3579 RELOCATION_RESERVED_NODES;
3580 ret = btrfs_block_rsv_refill(rc->extent_root->fs_info,
3581 rc->block_rsv, rc->block_rsv->size,
3582 BTRFS_RESERVE_FLUSH_ALL);
3583 if (ret)
3584 return ret;
3585
3586 rc->create_reloc_tree = 1;
3587 set_reloc_control(rc);
3588
3589 trans = btrfs_join_transaction(rc->extent_root);
3590 if (IS_ERR(trans)) {
3591 unset_reloc_control(rc);
3592 /*
3593 * extent tree is not a ref_cow tree and has no reloc_root to
3594 * cleanup. And callers are responsible to free the above
3595 * block rsv.
3596 */
3597 return PTR_ERR(trans);
3598 }
3599
3600 ret = btrfs_commit_transaction(trans);
3601 if (ret)
3602 unset_reloc_control(rc);
3603
3604 return ret;
3605}
3606
3607static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3608{
3609 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3610 struct rb_root blocks = RB_ROOT;
3611 struct btrfs_key key;
3612 struct btrfs_trans_handle *trans = NULL;
3613 struct btrfs_path *path;
3614 struct btrfs_extent_item *ei;
3615 u64 flags;
3616 int ret;
3617 int err = 0;
3618 int progress = 0;
3619
3620 path = btrfs_alloc_path();
3621 if (!path)
3622 return -ENOMEM;
3623 path->reada = READA_FORWARD;
3624
3625 ret = prepare_to_relocate(rc);
3626 if (ret) {
3627 err = ret;
3628 goto out_free;
3629 }
3630
3631 while (1) {
3632 rc->reserved_bytes = 0;
3633 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv,
3634 rc->block_rsv->size,
3635 BTRFS_RESERVE_FLUSH_ALL);
3636 if (ret) {
3637 err = ret;
3638 break;
3639 }
3640 progress++;
3641 trans = btrfs_start_transaction(rc->extent_root, 0);
3642 if (IS_ERR(trans)) {
3643 err = PTR_ERR(trans);
3644 trans = NULL;
3645 break;
3646 }
3647restart:
3648 if (update_backref_cache(trans, &rc->backref_cache)) {
3649 btrfs_end_transaction(trans);
3650 trans = NULL;
3651 continue;
3652 }
3653
3654 ret = find_next_extent(rc, path, &key);
3655 if (ret < 0)
3656 err = ret;
3657 if (ret != 0)
3658 break;
3659
3660 rc->extents_found++;
3661
3662 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3663 struct btrfs_extent_item);
3664 flags = btrfs_extent_flags(path->nodes[0], ei);
3665
3666 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3667 ret = add_tree_block(rc, &key, path, &blocks);
3668 } else if (rc->stage == UPDATE_DATA_PTRS &&
3669 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3670 ret = add_data_references(rc, &key, path, &blocks);
3671 } else {
3672 btrfs_release_path(path);
3673 ret = 0;
3674 }
3675 if (ret < 0) {
3676 err = ret;
3677 break;
3678 }
3679
3680 if (!RB_EMPTY_ROOT(&blocks)) {
3681 ret = relocate_tree_blocks(trans, rc, &blocks);
3682 if (ret < 0) {
3683 if (ret != -EAGAIN) {
3684 err = ret;
3685 break;
3686 }
3687 rc->extents_found--;
3688 rc->search_start = key.objectid;
3689 }
3690 }
3691
3692 btrfs_end_transaction_throttle(trans);
3693 btrfs_btree_balance_dirty(fs_info);
3694 trans = NULL;
3695
3696 if (rc->stage == MOVE_DATA_EXTENTS &&
3697 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3698 rc->found_file_extent = 1;
3699 ret = relocate_data_extent(rc->data_inode,
3700 &key, &rc->cluster);
3701 if (ret < 0) {
3702 err = ret;
3703 break;
3704 }
3705 }
3706 if (btrfs_should_cancel_balance(fs_info)) {
3707 err = -ECANCELED;
3708 break;
3709 }
3710 }
3711 if (trans && progress && err == -ENOSPC) {
3712 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
3713 if (ret == 1) {
3714 err = 0;
3715 progress = 0;
3716 goto restart;
3717 }
3718 }
3719
3720 btrfs_release_path(path);
3721 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
3722
3723 if (trans) {
3724 btrfs_end_transaction_throttle(trans);
3725 btrfs_btree_balance_dirty(fs_info);
3726 }
3727
3728 if (!err) {
3729 ret = relocate_file_extent_cluster(rc->data_inode,
3730 &rc->cluster);
3731 if (ret < 0)
3732 err = ret;
3733 }
3734
3735 rc->create_reloc_tree = 0;
3736 set_reloc_control(rc);
3737
3738 btrfs_backref_release_cache(&rc->backref_cache);
3739 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
3740
3741 /*
3742 * Even in the case when the relocation is cancelled, we should all go
3743 * through prepare_to_merge() and merge_reloc_roots().
3744 *
3745 * For error (including cancelled balance), prepare_to_merge() will
3746 * mark all reloc trees orphan, then queue them for cleanup in
3747 * merge_reloc_roots()
3748 */
3749 err = prepare_to_merge(rc, err);
3750
3751 merge_reloc_roots(rc);
3752
3753 rc->merge_reloc_tree = 0;
3754 unset_reloc_control(rc);
3755 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
3756
3757 /* get rid of pinned extents */
3758 trans = btrfs_join_transaction(rc->extent_root);
3759 if (IS_ERR(trans)) {
3760 err = PTR_ERR(trans);
3761 goto out_free;
3762 }
3763 ret = btrfs_commit_transaction(trans);
3764 if (ret && !err)
3765 err = ret;
3766out_free:
3767 ret = clean_dirty_subvols(rc);
3768 if (ret < 0 && !err)
3769 err = ret;
3770 btrfs_free_block_rsv(fs_info, rc->block_rsv);
3771 btrfs_free_path(path);
3772 return err;
3773}
3774
3775static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3776 struct btrfs_root *root, u64 objectid)
3777{
3778 struct btrfs_path *path;
3779 struct btrfs_inode_item *item;
3780 struct extent_buffer *leaf;
3781 int ret;
3782
3783 path = btrfs_alloc_path();
3784 if (!path)
3785 return -ENOMEM;
3786
3787 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3788 if (ret)
3789 goto out;
3790
3791 leaf = path->nodes[0];
3792 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3793 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
3794 btrfs_set_inode_generation(leaf, item, 1);
3795 btrfs_set_inode_size(leaf, item, 0);
3796 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3797 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3798 BTRFS_INODE_PREALLOC);
3799 btrfs_mark_buffer_dirty(leaf);
3800out:
3801 btrfs_free_path(path);
3802 return ret;
3803}
3804
3805static void delete_orphan_inode(struct btrfs_trans_handle *trans,
3806 struct btrfs_root *root, u64 objectid)
3807{
3808 struct btrfs_path *path;
3809 struct btrfs_key key;
3810 int ret = 0;
3811
3812 path = btrfs_alloc_path();
3813 if (!path) {
3814 ret = -ENOMEM;
3815 goto out;
3816 }
3817
3818 key.objectid = objectid;
3819 key.type = BTRFS_INODE_ITEM_KEY;
3820 key.offset = 0;
3821 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3822 if (ret) {
3823 if (ret > 0)
3824 ret = -ENOENT;
3825 goto out;
3826 }
3827 ret = btrfs_del_item(trans, root, path);
3828out:
3829 if (ret)
3830 btrfs_abort_transaction(trans, ret);
3831 btrfs_free_path(path);
3832}
3833
3834/*
3835 * helper to create inode for data relocation.
3836 * the inode is in data relocation tree and its link count is 0
3837 */
3838static noinline_for_stack
3839struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3840 struct btrfs_block_group *group)
3841{
3842 struct inode *inode = NULL;
3843 struct btrfs_trans_handle *trans;
3844 struct btrfs_root *root;
3845 u64 objectid;
3846 int err = 0;
3847
3848 root = btrfs_grab_root(fs_info->data_reloc_root);
3849 trans = btrfs_start_transaction(root, 6);
3850 if (IS_ERR(trans)) {
3851 btrfs_put_root(root);
3852 return ERR_CAST(trans);
3853 }
3854
3855 err = btrfs_get_free_objectid(root, &objectid);
3856 if (err)
3857 goto out;
3858
3859 err = __insert_orphan_inode(trans, root, objectid);
3860 if (err)
3861 goto out;
3862
3863 inode = btrfs_iget(fs_info->sb, objectid, root);
3864 if (IS_ERR(inode)) {
3865 delete_orphan_inode(trans, root, objectid);
3866 err = PTR_ERR(inode);
3867 inode = NULL;
3868 goto out;
3869 }
3870 BTRFS_I(inode)->index_cnt = group->start;
3871
3872 err = btrfs_orphan_add(trans, BTRFS_I(inode));
3873out:
3874 btrfs_put_root(root);
3875 btrfs_end_transaction(trans);
3876 btrfs_btree_balance_dirty(fs_info);
3877 if (err) {
3878 iput(inode);
3879 inode = ERR_PTR(err);
3880 }
3881 return inode;
3882}
3883
3884/*
3885 * Mark start of chunk relocation that is cancellable. Check if the cancellation
3886 * has been requested meanwhile and don't start in that case.
3887 *
3888 * Return:
3889 * 0 success
3890 * -EINPROGRESS operation is already in progress, that's probably a bug
3891 * -ECANCELED cancellation request was set before the operation started
3892 */
3893static int reloc_chunk_start(struct btrfs_fs_info *fs_info)
3894{
3895 if (test_and_set_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) {
3896 /* This should not happen */
3897 btrfs_err(fs_info, "reloc already running, cannot start");
3898 return -EINPROGRESS;
3899 }
3900
3901 if (atomic_read(&fs_info->reloc_cancel_req) > 0) {
3902 btrfs_info(fs_info, "chunk relocation canceled on start");
3903 /*
3904 * On cancel, clear all requests but let the caller mark
3905 * the end after cleanup operations.
3906 */
3907 atomic_set(&fs_info->reloc_cancel_req, 0);
3908 return -ECANCELED;
3909 }
3910 return 0;
3911}
3912
3913/*
3914 * Mark end of chunk relocation that is cancellable and wake any waiters.
3915 */
3916static void reloc_chunk_end(struct btrfs_fs_info *fs_info)
3917{
3918 /* Requested after start, clear bit first so any waiters can continue */
3919 if (atomic_read(&fs_info->reloc_cancel_req) > 0)
3920 btrfs_info(fs_info, "chunk relocation canceled during operation");
3921 clear_and_wake_up_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags);
3922 atomic_set(&fs_info->reloc_cancel_req, 0);
3923}
3924
3925static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
3926{
3927 struct reloc_control *rc;
3928
3929 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3930 if (!rc)
3931 return NULL;
3932
3933 INIT_LIST_HEAD(&rc->reloc_roots);
3934 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
3935 btrfs_backref_init_cache(fs_info, &rc->backref_cache, 1);
3936 mapping_tree_init(&rc->reloc_root_tree);
3937 extent_io_tree_init(fs_info, &rc->processed_blocks, IO_TREE_RELOC_BLOCKS);
3938 return rc;
3939}
3940
3941static void free_reloc_control(struct reloc_control *rc)
3942{
3943 struct mapping_node *node, *tmp;
3944
3945 free_reloc_roots(&rc->reloc_roots);
3946 rbtree_postorder_for_each_entry_safe(node, tmp,
3947 &rc->reloc_root_tree.rb_root, rb_node)
3948 kfree(node);
3949
3950 kfree(rc);
3951}
3952
3953/*
3954 * Print the block group being relocated
3955 */
3956static void describe_relocation(struct btrfs_fs_info *fs_info,
3957 struct btrfs_block_group *block_group)
3958{
3959 char buf[128] = {'\0'};
3960
3961 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
3962
3963 btrfs_info(fs_info,
3964 "relocating block group %llu flags %s",
3965 block_group->start, buf);
3966}
3967
3968static const char *stage_to_string(int stage)
3969{
3970 if (stage == MOVE_DATA_EXTENTS)
3971 return "move data extents";
3972 if (stage == UPDATE_DATA_PTRS)
3973 return "update data pointers";
3974 return "unknown";
3975}
3976
3977/*
3978 * function to relocate all extents in a block group.
3979 */
3980int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
3981{
3982 struct btrfs_block_group *bg;
3983 struct btrfs_root *extent_root = btrfs_extent_root(fs_info, group_start);
3984 struct reloc_control *rc;
3985 struct inode *inode;
3986 struct btrfs_path *path;
3987 int ret;
3988 int rw = 0;
3989 int err = 0;
3990
3991 /*
3992 * This only gets set if we had a half-deleted snapshot on mount. We
3993 * cannot allow relocation to start while we're still trying to clean up
3994 * these pending deletions.
3995 */
3996 ret = wait_on_bit(&fs_info->flags, BTRFS_FS_UNFINISHED_DROPS, TASK_INTERRUPTIBLE);
3997 if (ret)
3998 return ret;
3999
4000 /* We may have been woken up by close_ctree, so bail if we're closing. */
4001 if (btrfs_fs_closing(fs_info))
4002 return -EINTR;
4003
4004 bg = btrfs_lookup_block_group(fs_info, group_start);
4005 if (!bg)
4006 return -ENOENT;
4007
4008 /*
4009 * Relocation of a data block group creates ordered extents. Without
4010 * sb_start_write(), we can freeze the filesystem while unfinished
4011 * ordered extents are left. Such ordered extents can cause a deadlock
4012 * e.g. when syncfs() is waiting for their completion but they can't
4013 * finish because they block when joining a transaction, due to the
4014 * fact that the freeze locks are being held in write mode.
4015 */
4016 if (bg->flags & BTRFS_BLOCK_GROUP_DATA)
4017 ASSERT(sb_write_started(fs_info->sb));
4018
4019 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4020 btrfs_put_block_group(bg);
4021 return -ETXTBSY;
4022 }
4023
4024 rc = alloc_reloc_control(fs_info);
4025 if (!rc) {
4026 btrfs_put_block_group(bg);
4027 return -ENOMEM;
4028 }
4029
4030 ret = reloc_chunk_start(fs_info);
4031 if (ret < 0) {
4032 err = ret;
4033 goto out_put_bg;
4034 }
4035
4036 rc->extent_root = extent_root;
4037 rc->block_group = bg;
4038
4039 ret = btrfs_inc_block_group_ro(rc->block_group, true);
4040 if (ret) {
4041 err = ret;
4042 goto out;
4043 }
4044 rw = 1;
4045
4046 path = btrfs_alloc_path();
4047 if (!path) {
4048 err = -ENOMEM;
4049 goto out;
4050 }
4051
4052 inode = lookup_free_space_inode(rc->block_group, path);
4053 btrfs_free_path(path);
4054
4055 if (!IS_ERR(inode))
4056 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4057 else
4058 ret = PTR_ERR(inode);
4059
4060 if (ret && ret != -ENOENT) {
4061 err = ret;
4062 goto out;
4063 }
4064
4065 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4066 if (IS_ERR(rc->data_inode)) {
4067 err = PTR_ERR(rc->data_inode);
4068 rc->data_inode = NULL;
4069 goto out;
4070 }
4071
4072 describe_relocation(fs_info, rc->block_group);
4073
4074 btrfs_wait_block_group_reservations(rc->block_group);
4075 btrfs_wait_nocow_writers(rc->block_group);
4076 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4077 rc->block_group->start,
4078 rc->block_group->length);
4079
4080 ret = btrfs_zone_finish(rc->block_group);
4081 WARN_ON(ret && ret != -EAGAIN);
4082
4083 while (1) {
4084 int finishes_stage;
4085
4086 mutex_lock(&fs_info->cleaner_mutex);
4087 ret = relocate_block_group(rc);
4088 mutex_unlock(&fs_info->cleaner_mutex);
4089 if (ret < 0)
4090 err = ret;
4091
4092 finishes_stage = rc->stage;
4093 /*
4094 * We may have gotten ENOSPC after we already dirtied some
4095 * extents. If writeout happens while we're relocating a
4096 * different block group we could end up hitting the
4097 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4098 * btrfs_reloc_cow_block. Make sure we write everything out
4099 * properly so we don't trip over this problem, and then break
4100 * out of the loop if we hit an error.
4101 */
4102 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4103 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4104 (u64)-1);
4105 if (ret)
4106 err = ret;
4107 invalidate_mapping_pages(rc->data_inode->i_mapping,
4108 0, -1);
4109 rc->stage = UPDATE_DATA_PTRS;
4110 }
4111
4112 if (err < 0)
4113 goto out;
4114
4115 if (rc->extents_found == 0)
4116 break;
4117
4118 btrfs_info(fs_info, "found %llu extents, stage: %s",
4119 rc->extents_found, stage_to_string(finishes_stage));
4120 }
4121
4122 WARN_ON(rc->block_group->pinned > 0);
4123 WARN_ON(rc->block_group->reserved > 0);
4124 WARN_ON(rc->block_group->used > 0);
4125out:
4126 if (err && rw)
4127 btrfs_dec_block_group_ro(rc->block_group);
4128 iput(rc->data_inode);
4129out_put_bg:
4130 btrfs_put_block_group(bg);
4131 reloc_chunk_end(fs_info);
4132 free_reloc_control(rc);
4133 return err;
4134}
4135
4136static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4137{
4138 struct btrfs_fs_info *fs_info = root->fs_info;
4139 struct btrfs_trans_handle *trans;
4140 int ret, err;
4141
4142 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4143 if (IS_ERR(trans))
4144 return PTR_ERR(trans);
4145
4146 memset(&root->root_item.drop_progress, 0,
4147 sizeof(root->root_item.drop_progress));
4148 btrfs_set_root_drop_level(&root->root_item, 0);
4149 btrfs_set_root_refs(&root->root_item, 0);
4150 ret = btrfs_update_root(trans, fs_info->tree_root,
4151 &root->root_key, &root->root_item);
4152
4153 err = btrfs_end_transaction(trans);
4154 if (err)
4155 return err;
4156 return ret;
4157}
4158
4159/*
4160 * recover relocation interrupted by system crash.
4161 *
4162 * this function resumes merging reloc trees with corresponding fs trees.
4163 * this is important for keeping the sharing of tree blocks
4164 */
4165int btrfs_recover_relocation(struct btrfs_fs_info *fs_info)
4166{
4167 LIST_HEAD(reloc_roots);
4168 struct btrfs_key key;
4169 struct btrfs_root *fs_root;
4170 struct btrfs_root *reloc_root;
4171 struct btrfs_path *path;
4172 struct extent_buffer *leaf;
4173 struct reloc_control *rc = NULL;
4174 struct btrfs_trans_handle *trans;
4175 int ret;
4176 int err = 0;
4177
4178 path = btrfs_alloc_path();
4179 if (!path)
4180 return -ENOMEM;
4181 path->reada = READA_BACK;
4182
4183 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4184 key.type = BTRFS_ROOT_ITEM_KEY;
4185 key.offset = (u64)-1;
4186
4187 while (1) {
4188 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4189 path, 0, 0);
4190 if (ret < 0) {
4191 err = ret;
4192 goto out;
4193 }
4194 if (ret > 0) {
4195 if (path->slots[0] == 0)
4196 break;
4197 path->slots[0]--;
4198 }
4199 leaf = path->nodes[0];
4200 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4201 btrfs_release_path(path);
4202
4203 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4204 key.type != BTRFS_ROOT_ITEM_KEY)
4205 break;
4206
4207 reloc_root = btrfs_read_tree_root(fs_info->tree_root, &key);
4208 if (IS_ERR(reloc_root)) {
4209 err = PTR_ERR(reloc_root);
4210 goto out;
4211 }
4212
4213 set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
4214 list_add(&reloc_root->root_list, &reloc_roots);
4215
4216 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4217 fs_root = btrfs_get_fs_root(fs_info,
4218 reloc_root->root_key.offset, false);
4219 if (IS_ERR(fs_root)) {
4220 ret = PTR_ERR(fs_root);
4221 if (ret != -ENOENT) {
4222 err = ret;
4223 goto out;
4224 }
4225 ret = mark_garbage_root(reloc_root);
4226 if (ret < 0) {
4227 err = ret;
4228 goto out;
4229 }
4230 } else {
4231 btrfs_put_root(fs_root);
4232 }
4233 }
4234
4235 if (key.offset == 0)
4236 break;
4237
4238 key.offset--;
4239 }
4240 btrfs_release_path(path);
4241
4242 if (list_empty(&reloc_roots))
4243 goto out;
4244
4245 rc = alloc_reloc_control(fs_info);
4246 if (!rc) {
4247 err = -ENOMEM;
4248 goto out;
4249 }
4250
4251 ret = reloc_chunk_start(fs_info);
4252 if (ret < 0) {
4253 err = ret;
4254 goto out_end;
4255 }
4256
4257 rc->extent_root = btrfs_extent_root(fs_info, 0);
4258
4259 set_reloc_control(rc);
4260
4261 trans = btrfs_join_transaction(rc->extent_root);
4262 if (IS_ERR(trans)) {
4263 err = PTR_ERR(trans);
4264 goto out_unset;
4265 }
4266
4267 rc->merge_reloc_tree = 1;
4268
4269 while (!list_empty(&reloc_roots)) {
4270 reloc_root = list_entry(reloc_roots.next,
4271 struct btrfs_root, root_list);
4272 list_del(&reloc_root->root_list);
4273
4274 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4275 list_add_tail(&reloc_root->root_list,
4276 &rc->reloc_roots);
4277 continue;
4278 }
4279
4280 fs_root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
4281 false);
4282 if (IS_ERR(fs_root)) {
4283 err = PTR_ERR(fs_root);
4284 list_add_tail(&reloc_root->root_list, &reloc_roots);
4285 btrfs_end_transaction(trans);
4286 goto out_unset;
4287 }
4288
4289 err = __add_reloc_root(reloc_root);
4290 ASSERT(err != -EEXIST);
4291 if (err) {
4292 list_add_tail(&reloc_root->root_list, &reloc_roots);
4293 btrfs_put_root(fs_root);
4294 btrfs_end_transaction(trans);
4295 goto out_unset;
4296 }
4297 fs_root->reloc_root = btrfs_grab_root(reloc_root);
4298 btrfs_put_root(fs_root);
4299 }
4300
4301 err = btrfs_commit_transaction(trans);
4302 if (err)
4303 goto out_unset;
4304
4305 merge_reloc_roots(rc);
4306
4307 unset_reloc_control(rc);
4308
4309 trans = btrfs_join_transaction(rc->extent_root);
4310 if (IS_ERR(trans)) {
4311 err = PTR_ERR(trans);
4312 goto out_clean;
4313 }
4314 err = btrfs_commit_transaction(trans);
4315out_clean:
4316 ret = clean_dirty_subvols(rc);
4317 if (ret < 0 && !err)
4318 err = ret;
4319out_unset:
4320 unset_reloc_control(rc);
4321out_end:
4322 reloc_chunk_end(fs_info);
4323 free_reloc_control(rc);
4324out:
4325 free_reloc_roots(&reloc_roots);
4326
4327 btrfs_free_path(path);
4328
4329 if (err == 0) {
4330 /* cleanup orphan inode in data relocation tree */
4331 fs_root = btrfs_grab_root(fs_info->data_reloc_root);
4332 ASSERT(fs_root);
4333 err = btrfs_orphan_cleanup(fs_root);
4334 btrfs_put_root(fs_root);
4335 }
4336 return err;
4337}
4338
4339/*
4340 * helper to add ordered checksum for data relocation.
4341 *
4342 * cloning checksum properly handles the nodatasum extents.
4343 * it also saves CPU time to re-calculate the checksum.
4344 */
4345int btrfs_reloc_clone_csums(struct btrfs_inode *inode, u64 file_pos, u64 len)
4346{
4347 struct btrfs_fs_info *fs_info = inode->root->fs_info;
4348 struct btrfs_root *csum_root;
4349 struct btrfs_ordered_sum *sums;
4350 struct btrfs_ordered_extent *ordered;
4351 int ret;
4352 u64 disk_bytenr;
4353 u64 new_bytenr;
4354 LIST_HEAD(list);
4355
4356 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4357 BUG_ON(ordered->file_offset != file_pos || ordered->num_bytes != len);
4358
4359 disk_bytenr = file_pos + inode->index_cnt;
4360 csum_root = btrfs_csum_root(fs_info, disk_bytenr);
4361 ret = btrfs_lookup_csums_list(csum_root, disk_bytenr,
4362 disk_bytenr + len - 1, &list, 0, false);
4363 if (ret)
4364 goto out;
4365
4366 while (!list_empty(&list)) {
4367 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4368 list_del_init(&sums->list);
4369
4370 /*
4371 * We need to offset the new_bytenr based on where the csum is.
4372 * We need to do this because we will read in entire prealloc
4373 * extents but we may have written to say the middle of the
4374 * prealloc extent, so we need to make sure the csum goes with
4375 * the right disk offset.
4376 *
4377 * We can do this because the data reloc inode refers strictly
4378 * to the on disk bytes, so we don't have to worry about
4379 * disk_len vs real len like with real inodes since it's all
4380 * disk length.
4381 */
4382 new_bytenr = ordered->disk_bytenr + sums->bytenr - disk_bytenr;
4383 sums->bytenr = new_bytenr;
4384
4385 btrfs_add_ordered_sum(ordered, sums);
4386 }
4387out:
4388 btrfs_put_ordered_extent(ordered);
4389 return ret;
4390}
4391
4392int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4393 struct btrfs_root *root, struct extent_buffer *buf,
4394 struct extent_buffer *cow)
4395{
4396 struct btrfs_fs_info *fs_info = root->fs_info;
4397 struct reloc_control *rc;
4398 struct btrfs_backref_node *node;
4399 int first_cow = 0;
4400 int level;
4401 int ret = 0;
4402
4403 rc = fs_info->reloc_ctl;
4404 if (!rc)
4405 return 0;
4406
4407 BUG_ON(rc->stage == UPDATE_DATA_PTRS && btrfs_is_data_reloc_root(root));
4408
4409 level = btrfs_header_level(buf);
4410 if (btrfs_header_generation(buf) <=
4411 btrfs_root_last_snapshot(&root->root_item))
4412 first_cow = 1;
4413
4414 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4415 rc->create_reloc_tree) {
4416 WARN_ON(!first_cow && level == 0);
4417
4418 node = rc->backref_cache.path[level];
4419 BUG_ON(node->bytenr != buf->start &&
4420 node->new_bytenr != buf->start);
4421
4422 btrfs_backref_drop_node_buffer(node);
4423 atomic_inc(&cow->refs);
4424 node->eb = cow;
4425 node->new_bytenr = cow->start;
4426
4427 if (!node->pending) {
4428 list_move_tail(&node->list,
4429 &rc->backref_cache.pending[level]);
4430 node->pending = 1;
4431 }
4432
4433 if (first_cow)
4434 mark_block_processed(rc, node);
4435
4436 if (first_cow && level > 0)
4437 rc->nodes_relocated += buf->len;
4438 }
4439
4440 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4441 ret = replace_file_extents(trans, rc, root, cow);
4442 return ret;
4443}
4444
4445/*
4446 * called before creating snapshot. it calculates metadata reservation
4447 * required for relocating tree blocks in the snapshot
4448 */
4449void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4450 u64 *bytes_to_reserve)
4451{
4452 struct btrfs_root *root = pending->root;
4453 struct reloc_control *rc = root->fs_info->reloc_ctl;
4454
4455 if (!rc || !have_reloc_root(root))
4456 return;
4457
4458 if (!rc->merge_reloc_tree)
4459 return;
4460
4461 root = root->reloc_root;
4462 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4463 /*
4464 * relocation is in the stage of merging trees. the space
4465 * used by merging a reloc tree is twice the size of
4466 * relocated tree nodes in the worst case. half for cowing
4467 * the reloc tree, half for cowing the fs tree. the space
4468 * used by cowing the reloc tree will be freed after the
4469 * tree is dropped. if we create snapshot, cowing the fs
4470 * tree may use more space than it frees. so we need
4471 * reserve extra space.
4472 */
4473 *bytes_to_reserve += rc->nodes_relocated;
4474}
4475
4476/*
4477 * called after snapshot is created. migrate block reservation
4478 * and create reloc root for the newly created snapshot
4479 *
4480 * This is similar to btrfs_init_reloc_root(), we come out of here with two
4481 * references held on the reloc_root, one for root->reloc_root and one for
4482 * rc->reloc_roots.
4483 */
4484int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4485 struct btrfs_pending_snapshot *pending)
4486{
4487 struct btrfs_root *root = pending->root;
4488 struct btrfs_root *reloc_root;
4489 struct btrfs_root *new_root;
4490 struct reloc_control *rc = root->fs_info->reloc_ctl;
4491 int ret;
4492
4493 if (!rc || !have_reloc_root(root))
4494 return 0;
4495
4496 rc = root->fs_info->reloc_ctl;
4497 rc->merging_rsv_size += rc->nodes_relocated;
4498
4499 if (rc->merge_reloc_tree) {
4500 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4501 rc->block_rsv,
4502 rc->nodes_relocated, true);
4503 if (ret)
4504 return ret;
4505 }
4506
4507 new_root = pending->snap;
4508 reloc_root = create_reloc_root(trans, root->reloc_root,
4509 new_root->root_key.objectid);
4510 if (IS_ERR(reloc_root))
4511 return PTR_ERR(reloc_root);
4512
4513 ret = __add_reloc_root(reloc_root);
4514 ASSERT(ret != -EEXIST);
4515 if (ret) {
4516 /* Pairs with create_reloc_root */
4517 btrfs_put_root(reloc_root);
4518 return ret;
4519 }
4520 new_root->reloc_root = btrfs_grab_root(reloc_root);
4521
4522 if (rc->create_reloc_tree)
4523 ret = clone_backref_node(trans, rc, root, reloc_root);
4524 return ret;
4525}
1/*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/sched.h>
20#include <linux/pagemap.h>
21#include <linux/writeback.h>
22#include <linux/blkdev.h>
23#include <linux/rbtree.h>
24#include <linux/slab.h>
25#include "ctree.h"
26#include "disk-io.h"
27#include "transaction.h"
28#include "volumes.h"
29#include "locking.h"
30#include "btrfs_inode.h"
31#include "async-thread.h"
32#include "free-space-cache.h"
33#include "inode-map.h"
34
35/*
36 * backref_node, mapping_node and tree_block start with this
37 */
38struct tree_entry {
39 struct rb_node rb_node;
40 u64 bytenr;
41};
42
43/*
44 * present a tree block in the backref cache
45 */
46struct backref_node {
47 struct rb_node rb_node;
48 u64 bytenr;
49
50 u64 new_bytenr;
51 /* objectid of tree block owner, can be not uptodate */
52 u64 owner;
53 /* link to pending, changed or detached list */
54 struct list_head list;
55 /* list of upper level blocks reference this block */
56 struct list_head upper;
57 /* list of child blocks in the cache */
58 struct list_head lower;
59 /* NULL if this node is not tree root */
60 struct btrfs_root *root;
61 /* extent buffer got by COW the block */
62 struct extent_buffer *eb;
63 /* level of tree block */
64 unsigned int level:8;
65 /* is the block in non-reference counted tree */
66 unsigned int cowonly:1;
67 /* 1 if no child node in the cache */
68 unsigned int lowest:1;
69 /* is the extent buffer locked */
70 unsigned int locked:1;
71 /* has the block been processed */
72 unsigned int processed:1;
73 /* have backrefs of this block been checked */
74 unsigned int checked:1;
75 /*
76 * 1 if corresponding block has been cowed but some upper
77 * level block pointers may not point to the new location
78 */
79 unsigned int pending:1;
80 /*
81 * 1 if the backref node isn't connected to any other
82 * backref node.
83 */
84 unsigned int detached:1;
85};
86
87/*
88 * present a block pointer in the backref cache
89 */
90struct backref_edge {
91 struct list_head list[2];
92 struct backref_node *node[2];
93};
94
95#define LOWER 0
96#define UPPER 1
97#define RELOCATION_RESERVED_NODES 256
98
99struct backref_cache {
100 /* red black tree of all backref nodes in the cache */
101 struct rb_root rb_root;
102 /* for passing backref nodes to btrfs_reloc_cow_block */
103 struct backref_node *path[BTRFS_MAX_LEVEL];
104 /*
105 * list of blocks that have been cowed but some block
106 * pointers in upper level blocks may not reflect the
107 * new location
108 */
109 struct list_head pending[BTRFS_MAX_LEVEL];
110 /* list of backref nodes with no child node */
111 struct list_head leaves;
112 /* list of blocks that have been cowed in current transaction */
113 struct list_head changed;
114 /* list of detached backref node. */
115 struct list_head detached;
116
117 u64 last_trans;
118
119 int nr_nodes;
120 int nr_edges;
121};
122
123/*
124 * map address of tree root to tree
125 */
126struct mapping_node {
127 struct rb_node rb_node;
128 u64 bytenr;
129 void *data;
130};
131
132struct mapping_tree {
133 struct rb_root rb_root;
134 spinlock_t lock;
135};
136
137/*
138 * present a tree block to process
139 */
140struct tree_block {
141 struct rb_node rb_node;
142 u64 bytenr;
143 struct btrfs_key key;
144 unsigned int level:8;
145 unsigned int key_ready:1;
146};
147
148#define MAX_EXTENTS 128
149
150struct file_extent_cluster {
151 u64 start;
152 u64 end;
153 u64 boundary[MAX_EXTENTS];
154 unsigned int nr;
155};
156
157struct reloc_control {
158 /* block group to relocate */
159 struct btrfs_block_group_cache *block_group;
160 /* extent tree */
161 struct btrfs_root *extent_root;
162 /* inode for moving data */
163 struct inode *data_inode;
164
165 struct btrfs_block_rsv *block_rsv;
166
167 struct backref_cache backref_cache;
168
169 struct file_extent_cluster cluster;
170 /* tree blocks have been processed */
171 struct extent_io_tree processed_blocks;
172 /* map start of tree root to corresponding reloc tree */
173 struct mapping_tree reloc_root_tree;
174 /* list of reloc trees */
175 struct list_head reloc_roots;
176 /* size of metadata reservation for merging reloc trees */
177 u64 merging_rsv_size;
178 /* size of relocated tree nodes */
179 u64 nodes_relocated;
180 /* reserved size for block group relocation*/
181 u64 reserved_bytes;
182
183 u64 search_start;
184 u64 extents_found;
185
186 unsigned int stage:8;
187 unsigned int create_reloc_tree:1;
188 unsigned int merge_reloc_tree:1;
189 unsigned int found_file_extent:1;
190};
191
192/* stages of data relocation */
193#define MOVE_DATA_EXTENTS 0
194#define UPDATE_DATA_PTRS 1
195
196static void remove_backref_node(struct backref_cache *cache,
197 struct backref_node *node);
198static void __mark_block_processed(struct reloc_control *rc,
199 struct backref_node *node);
200
201static void mapping_tree_init(struct mapping_tree *tree)
202{
203 tree->rb_root = RB_ROOT;
204 spin_lock_init(&tree->lock);
205}
206
207static void backref_cache_init(struct backref_cache *cache)
208{
209 int i;
210 cache->rb_root = RB_ROOT;
211 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
212 INIT_LIST_HEAD(&cache->pending[i]);
213 INIT_LIST_HEAD(&cache->changed);
214 INIT_LIST_HEAD(&cache->detached);
215 INIT_LIST_HEAD(&cache->leaves);
216}
217
218static void backref_cache_cleanup(struct backref_cache *cache)
219{
220 struct backref_node *node;
221 int i;
222
223 while (!list_empty(&cache->detached)) {
224 node = list_entry(cache->detached.next,
225 struct backref_node, list);
226 remove_backref_node(cache, node);
227 }
228
229 while (!list_empty(&cache->leaves)) {
230 node = list_entry(cache->leaves.next,
231 struct backref_node, lower);
232 remove_backref_node(cache, node);
233 }
234
235 cache->last_trans = 0;
236
237 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
238 BUG_ON(!list_empty(&cache->pending[i]));
239 BUG_ON(!list_empty(&cache->changed));
240 BUG_ON(!list_empty(&cache->detached));
241 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
242 BUG_ON(cache->nr_nodes);
243 BUG_ON(cache->nr_edges);
244}
245
246static struct backref_node *alloc_backref_node(struct backref_cache *cache)
247{
248 struct backref_node *node;
249
250 node = kzalloc(sizeof(*node), GFP_NOFS);
251 if (node) {
252 INIT_LIST_HEAD(&node->list);
253 INIT_LIST_HEAD(&node->upper);
254 INIT_LIST_HEAD(&node->lower);
255 RB_CLEAR_NODE(&node->rb_node);
256 cache->nr_nodes++;
257 }
258 return node;
259}
260
261static void free_backref_node(struct backref_cache *cache,
262 struct backref_node *node)
263{
264 if (node) {
265 cache->nr_nodes--;
266 kfree(node);
267 }
268}
269
270static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
271{
272 struct backref_edge *edge;
273
274 edge = kzalloc(sizeof(*edge), GFP_NOFS);
275 if (edge)
276 cache->nr_edges++;
277 return edge;
278}
279
280static void free_backref_edge(struct backref_cache *cache,
281 struct backref_edge *edge)
282{
283 if (edge) {
284 cache->nr_edges--;
285 kfree(edge);
286 }
287}
288
289static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
290 struct rb_node *node)
291{
292 struct rb_node **p = &root->rb_node;
293 struct rb_node *parent = NULL;
294 struct tree_entry *entry;
295
296 while (*p) {
297 parent = *p;
298 entry = rb_entry(parent, struct tree_entry, rb_node);
299
300 if (bytenr < entry->bytenr)
301 p = &(*p)->rb_left;
302 else if (bytenr > entry->bytenr)
303 p = &(*p)->rb_right;
304 else
305 return parent;
306 }
307
308 rb_link_node(node, parent, p);
309 rb_insert_color(node, root);
310 return NULL;
311}
312
313static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
314{
315 struct rb_node *n = root->rb_node;
316 struct tree_entry *entry;
317
318 while (n) {
319 entry = rb_entry(n, struct tree_entry, rb_node);
320
321 if (bytenr < entry->bytenr)
322 n = n->rb_left;
323 else if (bytenr > entry->bytenr)
324 n = n->rb_right;
325 else
326 return n;
327 }
328 return NULL;
329}
330
331static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
332{
333
334 struct btrfs_fs_info *fs_info = NULL;
335 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
336 rb_node);
337 if (bnode->root)
338 fs_info = bnode->root->fs_info;
339 btrfs_panic(fs_info, errno, "Inconsistency in backref cache "
340 "found at offset %llu", bytenr);
341}
342
343/*
344 * walk up backref nodes until reach node presents tree root
345 */
346static struct backref_node *walk_up_backref(struct backref_node *node,
347 struct backref_edge *edges[],
348 int *index)
349{
350 struct backref_edge *edge;
351 int idx = *index;
352
353 while (!list_empty(&node->upper)) {
354 edge = list_entry(node->upper.next,
355 struct backref_edge, list[LOWER]);
356 edges[idx++] = edge;
357 node = edge->node[UPPER];
358 }
359 BUG_ON(node->detached);
360 *index = idx;
361 return node;
362}
363
364/*
365 * walk down backref nodes to find start of next reference path
366 */
367static struct backref_node *walk_down_backref(struct backref_edge *edges[],
368 int *index)
369{
370 struct backref_edge *edge;
371 struct backref_node *lower;
372 int idx = *index;
373
374 while (idx > 0) {
375 edge = edges[idx - 1];
376 lower = edge->node[LOWER];
377 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
378 idx--;
379 continue;
380 }
381 edge = list_entry(edge->list[LOWER].next,
382 struct backref_edge, list[LOWER]);
383 edges[idx - 1] = edge;
384 *index = idx;
385 return edge->node[UPPER];
386 }
387 *index = 0;
388 return NULL;
389}
390
391static void unlock_node_buffer(struct backref_node *node)
392{
393 if (node->locked) {
394 btrfs_tree_unlock(node->eb);
395 node->locked = 0;
396 }
397}
398
399static void drop_node_buffer(struct backref_node *node)
400{
401 if (node->eb) {
402 unlock_node_buffer(node);
403 free_extent_buffer(node->eb);
404 node->eb = NULL;
405 }
406}
407
408static void drop_backref_node(struct backref_cache *tree,
409 struct backref_node *node)
410{
411 BUG_ON(!list_empty(&node->upper));
412
413 drop_node_buffer(node);
414 list_del(&node->list);
415 list_del(&node->lower);
416 if (!RB_EMPTY_NODE(&node->rb_node))
417 rb_erase(&node->rb_node, &tree->rb_root);
418 free_backref_node(tree, node);
419}
420
421/*
422 * remove a backref node from the backref cache
423 */
424static void remove_backref_node(struct backref_cache *cache,
425 struct backref_node *node)
426{
427 struct backref_node *upper;
428 struct backref_edge *edge;
429
430 if (!node)
431 return;
432
433 BUG_ON(!node->lowest && !node->detached);
434 while (!list_empty(&node->upper)) {
435 edge = list_entry(node->upper.next, struct backref_edge,
436 list[LOWER]);
437 upper = edge->node[UPPER];
438 list_del(&edge->list[LOWER]);
439 list_del(&edge->list[UPPER]);
440 free_backref_edge(cache, edge);
441
442 if (RB_EMPTY_NODE(&upper->rb_node)) {
443 BUG_ON(!list_empty(&node->upper));
444 drop_backref_node(cache, node);
445 node = upper;
446 node->lowest = 1;
447 continue;
448 }
449 /*
450 * add the node to leaf node list if no other
451 * child block cached.
452 */
453 if (list_empty(&upper->lower)) {
454 list_add_tail(&upper->lower, &cache->leaves);
455 upper->lowest = 1;
456 }
457 }
458
459 drop_backref_node(cache, node);
460}
461
462static void update_backref_node(struct backref_cache *cache,
463 struct backref_node *node, u64 bytenr)
464{
465 struct rb_node *rb_node;
466 rb_erase(&node->rb_node, &cache->rb_root);
467 node->bytenr = bytenr;
468 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
469 if (rb_node)
470 backref_tree_panic(rb_node, -EEXIST, bytenr);
471}
472
473/*
474 * update backref cache after a transaction commit
475 */
476static int update_backref_cache(struct btrfs_trans_handle *trans,
477 struct backref_cache *cache)
478{
479 struct backref_node *node;
480 int level = 0;
481
482 if (cache->last_trans == 0) {
483 cache->last_trans = trans->transid;
484 return 0;
485 }
486
487 if (cache->last_trans == trans->transid)
488 return 0;
489
490 /*
491 * detached nodes are used to avoid unnecessary backref
492 * lookup. transaction commit changes the extent tree.
493 * so the detached nodes are no longer useful.
494 */
495 while (!list_empty(&cache->detached)) {
496 node = list_entry(cache->detached.next,
497 struct backref_node, list);
498 remove_backref_node(cache, node);
499 }
500
501 while (!list_empty(&cache->changed)) {
502 node = list_entry(cache->changed.next,
503 struct backref_node, list);
504 list_del_init(&node->list);
505 BUG_ON(node->pending);
506 update_backref_node(cache, node, node->new_bytenr);
507 }
508
509 /*
510 * some nodes can be left in the pending list if there were
511 * errors during processing the pending nodes.
512 */
513 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
514 list_for_each_entry(node, &cache->pending[level], list) {
515 BUG_ON(!node->pending);
516 if (node->bytenr == node->new_bytenr)
517 continue;
518 update_backref_node(cache, node, node->new_bytenr);
519 }
520 }
521
522 cache->last_trans = 0;
523 return 1;
524}
525
526
527static int should_ignore_root(struct btrfs_root *root)
528{
529 struct btrfs_root *reloc_root;
530
531 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
532 return 0;
533
534 reloc_root = root->reloc_root;
535 if (!reloc_root)
536 return 0;
537
538 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
539 root->fs_info->running_transaction->transid - 1)
540 return 0;
541 /*
542 * if there is reloc tree and it was created in previous
543 * transaction backref lookup can find the reloc tree,
544 * so backref node for the fs tree root is useless for
545 * relocation.
546 */
547 return 1;
548}
549/*
550 * find reloc tree by address of tree root
551 */
552static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
553 u64 bytenr)
554{
555 struct rb_node *rb_node;
556 struct mapping_node *node;
557 struct btrfs_root *root = NULL;
558
559 spin_lock(&rc->reloc_root_tree.lock);
560 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
561 if (rb_node) {
562 node = rb_entry(rb_node, struct mapping_node, rb_node);
563 root = (struct btrfs_root *)node->data;
564 }
565 spin_unlock(&rc->reloc_root_tree.lock);
566 return root;
567}
568
569static int is_cowonly_root(u64 root_objectid)
570{
571 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
572 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
573 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
574 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
575 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
576 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
577 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
578 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
579 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
580 return 1;
581 return 0;
582}
583
584static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
585 u64 root_objectid)
586{
587 struct btrfs_key key;
588
589 key.objectid = root_objectid;
590 key.type = BTRFS_ROOT_ITEM_KEY;
591 if (is_cowonly_root(root_objectid))
592 key.offset = 0;
593 else
594 key.offset = (u64)-1;
595
596 return btrfs_get_fs_root(fs_info, &key, false);
597}
598
599#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
600static noinline_for_stack
601struct btrfs_root *find_tree_root(struct reloc_control *rc,
602 struct extent_buffer *leaf,
603 struct btrfs_extent_ref_v0 *ref0)
604{
605 struct btrfs_root *root;
606 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
607 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
608
609 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
610
611 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
612 BUG_ON(IS_ERR(root));
613
614 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
615 generation != btrfs_root_generation(&root->root_item))
616 return NULL;
617
618 return root;
619}
620#endif
621
622static noinline_for_stack
623int find_inline_backref(struct extent_buffer *leaf, int slot,
624 unsigned long *ptr, unsigned long *end)
625{
626 struct btrfs_key key;
627 struct btrfs_extent_item *ei;
628 struct btrfs_tree_block_info *bi;
629 u32 item_size;
630
631 btrfs_item_key_to_cpu(leaf, &key, slot);
632
633 item_size = btrfs_item_size_nr(leaf, slot);
634#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
635 if (item_size < sizeof(*ei)) {
636 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
637 return 1;
638 }
639#endif
640 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
641 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
642 BTRFS_EXTENT_FLAG_TREE_BLOCK));
643
644 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
645 item_size <= sizeof(*ei) + sizeof(*bi)) {
646 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
647 return 1;
648 }
649 if (key.type == BTRFS_METADATA_ITEM_KEY &&
650 item_size <= sizeof(*ei)) {
651 WARN_ON(item_size < sizeof(*ei));
652 return 1;
653 }
654
655 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
656 bi = (struct btrfs_tree_block_info *)(ei + 1);
657 *ptr = (unsigned long)(bi + 1);
658 } else {
659 *ptr = (unsigned long)(ei + 1);
660 }
661 *end = (unsigned long)ei + item_size;
662 return 0;
663}
664
665/*
666 * build backref tree for a given tree block. root of the backref tree
667 * corresponds the tree block, leaves of the backref tree correspond
668 * roots of b-trees that reference the tree block.
669 *
670 * the basic idea of this function is check backrefs of a given block
671 * to find upper level blocks that refernece the block, and then check
672 * bakcrefs of these upper level blocks recursively. the recursion stop
673 * when tree root is reached or backrefs for the block is cached.
674 *
675 * NOTE: if we find backrefs for a block are cached, we know backrefs
676 * for all upper level blocks that directly/indirectly reference the
677 * block are also cached.
678 */
679static noinline_for_stack
680struct backref_node *build_backref_tree(struct reloc_control *rc,
681 struct btrfs_key *node_key,
682 int level, u64 bytenr)
683{
684 struct backref_cache *cache = &rc->backref_cache;
685 struct btrfs_path *path1;
686 struct btrfs_path *path2;
687 struct extent_buffer *eb;
688 struct btrfs_root *root;
689 struct backref_node *cur;
690 struct backref_node *upper;
691 struct backref_node *lower;
692 struct backref_node *node = NULL;
693 struct backref_node *exist = NULL;
694 struct backref_edge *edge;
695 struct rb_node *rb_node;
696 struct btrfs_key key;
697 unsigned long end;
698 unsigned long ptr;
699 LIST_HEAD(list);
700 LIST_HEAD(useless);
701 int cowonly;
702 int ret;
703 int err = 0;
704 bool need_check = true;
705
706 path1 = btrfs_alloc_path();
707 path2 = btrfs_alloc_path();
708 if (!path1 || !path2) {
709 err = -ENOMEM;
710 goto out;
711 }
712 path1->reada = READA_FORWARD;
713 path2->reada = READA_FORWARD;
714
715 node = alloc_backref_node(cache);
716 if (!node) {
717 err = -ENOMEM;
718 goto out;
719 }
720
721 node->bytenr = bytenr;
722 node->level = level;
723 node->lowest = 1;
724 cur = node;
725again:
726 end = 0;
727 ptr = 0;
728 key.objectid = cur->bytenr;
729 key.type = BTRFS_METADATA_ITEM_KEY;
730 key.offset = (u64)-1;
731
732 path1->search_commit_root = 1;
733 path1->skip_locking = 1;
734 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
735 0, 0);
736 if (ret < 0) {
737 err = ret;
738 goto out;
739 }
740 ASSERT(ret);
741 ASSERT(path1->slots[0]);
742
743 path1->slots[0]--;
744
745 WARN_ON(cur->checked);
746 if (!list_empty(&cur->upper)) {
747 /*
748 * the backref was added previously when processing
749 * backref of type BTRFS_TREE_BLOCK_REF_KEY
750 */
751 ASSERT(list_is_singular(&cur->upper));
752 edge = list_entry(cur->upper.next, struct backref_edge,
753 list[LOWER]);
754 ASSERT(list_empty(&edge->list[UPPER]));
755 exist = edge->node[UPPER];
756 /*
757 * add the upper level block to pending list if we need
758 * check its backrefs
759 */
760 if (!exist->checked)
761 list_add_tail(&edge->list[UPPER], &list);
762 } else {
763 exist = NULL;
764 }
765
766 while (1) {
767 cond_resched();
768 eb = path1->nodes[0];
769
770 if (ptr >= end) {
771 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
772 ret = btrfs_next_leaf(rc->extent_root, path1);
773 if (ret < 0) {
774 err = ret;
775 goto out;
776 }
777 if (ret > 0)
778 break;
779 eb = path1->nodes[0];
780 }
781
782 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
783 if (key.objectid != cur->bytenr) {
784 WARN_ON(exist);
785 break;
786 }
787
788 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
789 key.type == BTRFS_METADATA_ITEM_KEY) {
790 ret = find_inline_backref(eb, path1->slots[0],
791 &ptr, &end);
792 if (ret)
793 goto next;
794 }
795 }
796
797 if (ptr < end) {
798 /* update key for inline back ref */
799 struct btrfs_extent_inline_ref *iref;
800 iref = (struct btrfs_extent_inline_ref *)ptr;
801 key.type = btrfs_extent_inline_ref_type(eb, iref);
802 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
803 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
804 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
805 }
806
807 if (exist &&
808 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
809 exist->owner == key.offset) ||
810 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
811 exist->bytenr == key.offset))) {
812 exist = NULL;
813 goto next;
814 }
815
816#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
817 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
818 key.type == BTRFS_EXTENT_REF_V0_KEY) {
819 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
820 struct btrfs_extent_ref_v0 *ref0;
821 ref0 = btrfs_item_ptr(eb, path1->slots[0],
822 struct btrfs_extent_ref_v0);
823 if (key.objectid == key.offset) {
824 root = find_tree_root(rc, eb, ref0);
825 if (root && !should_ignore_root(root))
826 cur->root = root;
827 else
828 list_add(&cur->list, &useless);
829 break;
830 }
831 if (is_cowonly_root(btrfs_ref_root_v0(eb,
832 ref0)))
833 cur->cowonly = 1;
834 }
835#else
836 ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
837 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
838#endif
839 if (key.objectid == key.offset) {
840 /*
841 * only root blocks of reloc trees use
842 * backref of this type.
843 */
844 root = find_reloc_root(rc, cur->bytenr);
845 ASSERT(root);
846 cur->root = root;
847 break;
848 }
849
850 edge = alloc_backref_edge(cache);
851 if (!edge) {
852 err = -ENOMEM;
853 goto out;
854 }
855 rb_node = tree_search(&cache->rb_root, key.offset);
856 if (!rb_node) {
857 upper = alloc_backref_node(cache);
858 if (!upper) {
859 free_backref_edge(cache, edge);
860 err = -ENOMEM;
861 goto out;
862 }
863 upper->bytenr = key.offset;
864 upper->level = cur->level + 1;
865 /*
866 * backrefs for the upper level block isn't
867 * cached, add the block to pending list
868 */
869 list_add_tail(&edge->list[UPPER], &list);
870 } else {
871 upper = rb_entry(rb_node, struct backref_node,
872 rb_node);
873 ASSERT(upper->checked);
874 INIT_LIST_HEAD(&edge->list[UPPER]);
875 }
876 list_add_tail(&edge->list[LOWER], &cur->upper);
877 edge->node[LOWER] = cur;
878 edge->node[UPPER] = upper;
879
880 goto next;
881 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
882 goto next;
883 }
884
885 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
886 root = read_fs_root(rc->extent_root->fs_info, key.offset);
887 if (IS_ERR(root)) {
888 err = PTR_ERR(root);
889 goto out;
890 }
891
892 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
893 cur->cowonly = 1;
894
895 if (btrfs_root_level(&root->root_item) == cur->level) {
896 /* tree root */
897 ASSERT(btrfs_root_bytenr(&root->root_item) ==
898 cur->bytenr);
899 if (should_ignore_root(root))
900 list_add(&cur->list, &useless);
901 else
902 cur->root = root;
903 break;
904 }
905
906 level = cur->level + 1;
907
908 /*
909 * searching the tree to find upper level blocks
910 * reference the block.
911 */
912 path2->search_commit_root = 1;
913 path2->skip_locking = 1;
914 path2->lowest_level = level;
915 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
916 path2->lowest_level = 0;
917 if (ret < 0) {
918 err = ret;
919 goto out;
920 }
921 if (ret > 0 && path2->slots[level] > 0)
922 path2->slots[level]--;
923
924 eb = path2->nodes[level];
925 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
926 cur->bytenr);
927
928 lower = cur;
929 need_check = true;
930 for (; level < BTRFS_MAX_LEVEL; level++) {
931 if (!path2->nodes[level]) {
932 ASSERT(btrfs_root_bytenr(&root->root_item) ==
933 lower->bytenr);
934 if (should_ignore_root(root))
935 list_add(&lower->list, &useless);
936 else
937 lower->root = root;
938 break;
939 }
940
941 edge = alloc_backref_edge(cache);
942 if (!edge) {
943 err = -ENOMEM;
944 goto out;
945 }
946
947 eb = path2->nodes[level];
948 rb_node = tree_search(&cache->rb_root, eb->start);
949 if (!rb_node) {
950 upper = alloc_backref_node(cache);
951 if (!upper) {
952 free_backref_edge(cache, edge);
953 err = -ENOMEM;
954 goto out;
955 }
956 upper->bytenr = eb->start;
957 upper->owner = btrfs_header_owner(eb);
958 upper->level = lower->level + 1;
959 if (!test_bit(BTRFS_ROOT_REF_COWS,
960 &root->state))
961 upper->cowonly = 1;
962
963 /*
964 * if we know the block isn't shared
965 * we can void checking its backrefs.
966 */
967 if (btrfs_block_can_be_shared(root, eb))
968 upper->checked = 0;
969 else
970 upper->checked = 1;
971
972 /*
973 * add the block to pending list if we
974 * need check its backrefs, we only do this once
975 * while walking up a tree as we will catch
976 * anything else later on.
977 */
978 if (!upper->checked && need_check) {
979 need_check = false;
980 list_add_tail(&edge->list[UPPER],
981 &list);
982 } else {
983 if (upper->checked)
984 need_check = true;
985 INIT_LIST_HEAD(&edge->list[UPPER]);
986 }
987 } else {
988 upper = rb_entry(rb_node, struct backref_node,
989 rb_node);
990 ASSERT(upper->checked);
991 INIT_LIST_HEAD(&edge->list[UPPER]);
992 if (!upper->owner)
993 upper->owner = btrfs_header_owner(eb);
994 }
995 list_add_tail(&edge->list[LOWER], &lower->upper);
996 edge->node[LOWER] = lower;
997 edge->node[UPPER] = upper;
998
999 if (rb_node)
1000 break;
1001 lower = upper;
1002 upper = NULL;
1003 }
1004 btrfs_release_path(path2);
1005next:
1006 if (ptr < end) {
1007 ptr += btrfs_extent_inline_ref_size(key.type);
1008 if (ptr >= end) {
1009 WARN_ON(ptr > end);
1010 ptr = 0;
1011 end = 0;
1012 }
1013 }
1014 if (ptr >= end)
1015 path1->slots[0]++;
1016 }
1017 btrfs_release_path(path1);
1018
1019 cur->checked = 1;
1020 WARN_ON(exist);
1021
1022 /* the pending list isn't empty, take the first block to process */
1023 if (!list_empty(&list)) {
1024 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1025 list_del_init(&edge->list[UPPER]);
1026 cur = edge->node[UPPER];
1027 goto again;
1028 }
1029
1030 /*
1031 * everything goes well, connect backref nodes and insert backref nodes
1032 * into the cache.
1033 */
1034 ASSERT(node->checked);
1035 cowonly = node->cowonly;
1036 if (!cowonly) {
1037 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1038 &node->rb_node);
1039 if (rb_node)
1040 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1041 list_add_tail(&node->lower, &cache->leaves);
1042 }
1043
1044 list_for_each_entry(edge, &node->upper, list[LOWER])
1045 list_add_tail(&edge->list[UPPER], &list);
1046
1047 while (!list_empty(&list)) {
1048 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1049 list_del_init(&edge->list[UPPER]);
1050 upper = edge->node[UPPER];
1051 if (upper->detached) {
1052 list_del(&edge->list[LOWER]);
1053 lower = edge->node[LOWER];
1054 free_backref_edge(cache, edge);
1055 if (list_empty(&lower->upper))
1056 list_add(&lower->list, &useless);
1057 continue;
1058 }
1059
1060 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1061 if (upper->lowest) {
1062 list_del_init(&upper->lower);
1063 upper->lowest = 0;
1064 }
1065
1066 list_add_tail(&edge->list[UPPER], &upper->lower);
1067 continue;
1068 }
1069
1070 if (!upper->checked) {
1071 /*
1072 * Still want to blow up for developers since this is a
1073 * logic bug.
1074 */
1075 ASSERT(0);
1076 err = -EINVAL;
1077 goto out;
1078 }
1079 if (cowonly != upper->cowonly) {
1080 ASSERT(0);
1081 err = -EINVAL;
1082 goto out;
1083 }
1084
1085 if (!cowonly) {
1086 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1087 &upper->rb_node);
1088 if (rb_node)
1089 backref_tree_panic(rb_node, -EEXIST,
1090 upper->bytenr);
1091 }
1092
1093 list_add_tail(&edge->list[UPPER], &upper->lower);
1094
1095 list_for_each_entry(edge, &upper->upper, list[LOWER])
1096 list_add_tail(&edge->list[UPPER], &list);
1097 }
1098 /*
1099 * process useless backref nodes. backref nodes for tree leaves
1100 * are deleted from the cache. backref nodes for upper level
1101 * tree blocks are left in the cache to avoid unnecessary backref
1102 * lookup.
1103 */
1104 while (!list_empty(&useless)) {
1105 upper = list_entry(useless.next, struct backref_node, list);
1106 list_del_init(&upper->list);
1107 ASSERT(list_empty(&upper->upper));
1108 if (upper == node)
1109 node = NULL;
1110 if (upper->lowest) {
1111 list_del_init(&upper->lower);
1112 upper->lowest = 0;
1113 }
1114 while (!list_empty(&upper->lower)) {
1115 edge = list_entry(upper->lower.next,
1116 struct backref_edge, list[UPPER]);
1117 list_del(&edge->list[UPPER]);
1118 list_del(&edge->list[LOWER]);
1119 lower = edge->node[LOWER];
1120 free_backref_edge(cache, edge);
1121
1122 if (list_empty(&lower->upper))
1123 list_add(&lower->list, &useless);
1124 }
1125 __mark_block_processed(rc, upper);
1126 if (upper->level > 0) {
1127 list_add(&upper->list, &cache->detached);
1128 upper->detached = 1;
1129 } else {
1130 rb_erase(&upper->rb_node, &cache->rb_root);
1131 free_backref_node(cache, upper);
1132 }
1133 }
1134out:
1135 btrfs_free_path(path1);
1136 btrfs_free_path(path2);
1137 if (err) {
1138 while (!list_empty(&useless)) {
1139 lower = list_entry(useless.next,
1140 struct backref_node, list);
1141 list_del_init(&lower->list);
1142 }
1143 while (!list_empty(&list)) {
1144 edge = list_first_entry(&list, struct backref_edge,
1145 list[UPPER]);
1146 list_del(&edge->list[UPPER]);
1147 list_del(&edge->list[LOWER]);
1148 lower = edge->node[LOWER];
1149 upper = edge->node[UPPER];
1150 free_backref_edge(cache, edge);
1151
1152 /*
1153 * Lower is no longer linked to any upper backref nodes
1154 * and isn't in the cache, we can free it ourselves.
1155 */
1156 if (list_empty(&lower->upper) &&
1157 RB_EMPTY_NODE(&lower->rb_node))
1158 list_add(&lower->list, &useless);
1159
1160 if (!RB_EMPTY_NODE(&upper->rb_node))
1161 continue;
1162
1163 /* Add this guy's upper edges to the list to proces */
1164 list_for_each_entry(edge, &upper->upper, list[LOWER])
1165 list_add_tail(&edge->list[UPPER], &list);
1166 if (list_empty(&upper->upper))
1167 list_add(&upper->list, &useless);
1168 }
1169
1170 while (!list_empty(&useless)) {
1171 lower = list_entry(useless.next,
1172 struct backref_node, list);
1173 list_del_init(&lower->list);
1174 free_backref_node(cache, lower);
1175 }
1176 return ERR_PTR(err);
1177 }
1178 ASSERT(!node || !node->detached);
1179 return node;
1180}
1181
1182/*
1183 * helper to add backref node for the newly created snapshot.
1184 * the backref node is created by cloning backref node that
1185 * corresponds to root of source tree
1186 */
1187static int clone_backref_node(struct btrfs_trans_handle *trans,
1188 struct reloc_control *rc,
1189 struct btrfs_root *src,
1190 struct btrfs_root *dest)
1191{
1192 struct btrfs_root *reloc_root = src->reloc_root;
1193 struct backref_cache *cache = &rc->backref_cache;
1194 struct backref_node *node = NULL;
1195 struct backref_node *new_node;
1196 struct backref_edge *edge;
1197 struct backref_edge *new_edge;
1198 struct rb_node *rb_node;
1199
1200 if (cache->last_trans > 0)
1201 update_backref_cache(trans, cache);
1202
1203 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1204 if (rb_node) {
1205 node = rb_entry(rb_node, struct backref_node, rb_node);
1206 if (node->detached)
1207 node = NULL;
1208 else
1209 BUG_ON(node->new_bytenr != reloc_root->node->start);
1210 }
1211
1212 if (!node) {
1213 rb_node = tree_search(&cache->rb_root,
1214 reloc_root->commit_root->start);
1215 if (rb_node) {
1216 node = rb_entry(rb_node, struct backref_node,
1217 rb_node);
1218 BUG_ON(node->detached);
1219 }
1220 }
1221
1222 if (!node)
1223 return 0;
1224
1225 new_node = alloc_backref_node(cache);
1226 if (!new_node)
1227 return -ENOMEM;
1228
1229 new_node->bytenr = dest->node->start;
1230 new_node->level = node->level;
1231 new_node->lowest = node->lowest;
1232 new_node->checked = 1;
1233 new_node->root = dest;
1234
1235 if (!node->lowest) {
1236 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1237 new_edge = alloc_backref_edge(cache);
1238 if (!new_edge)
1239 goto fail;
1240
1241 new_edge->node[UPPER] = new_node;
1242 new_edge->node[LOWER] = edge->node[LOWER];
1243 list_add_tail(&new_edge->list[UPPER],
1244 &new_node->lower);
1245 }
1246 } else {
1247 list_add_tail(&new_node->lower, &cache->leaves);
1248 }
1249
1250 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1251 &new_node->rb_node);
1252 if (rb_node)
1253 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1254
1255 if (!new_node->lowest) {
1256 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1257 list_add_tail(&new_edge->list[LOWER],
1258 &new_edge->node[LOWER]->upper);
1259 }
1260 }
1261 return 0;
1262fail:
1263 while (!list_empty(&new_node->lower)) {
1264 new_edge = list_entry(new_node->lower.next,
1265 struct backref_edge, list[UPPER]);
1266 list_del(&new_edge->list[UPPER]);
1267 free_backref_edge(cache, new_edge);
1268 }
1269 free_backref_node(cache, new_node);
1270 return -ENOMEM;
1271}
1272
1273/*
1274 * helper to add 'address of tree root -> reloc tree' mapping
1275 */
1276static int __must_check __add_reloc_root(struct btrfs_root *root)
1277{
1278 struct rb_node *rb_node;
1279 struct mapping_node *node;
1280 struct reloc_control *rc = root->fs_info->reloc_ctl;
1281
1282 node = kmalloc(sizeof(*node), GFP_NOFS);
1283 if (!node)
1284 return -ENOMEM;
1285
1286 node->bytenr = root->node->start;
1287 node->data = root;
1288
1289 spin_lock(&rc->reloc_root_tree.lock);
1290 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1291 node->bytenr, &node->rb_node);
1292 spin_unlock(&rc->reloc_root_tree.lock);
1293 if (rb_node) {
1294 btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
1295 "for start=%llu while inserting into relocation "
1296 "tree", node->bytenr);
1297 kfree(node);
1298 return -EEXIST;
1299 }
1300
1301 list_add_tail(&root->root_list, &rc->reloc_roots);
1302 return 0;
1303}
1304
1305/*
1306 * helper to delete the 'address of tree root -> reloc tree'
1307 * mapping
1308 */
1309static void __del_reloc_root(struct btrfs_root *root)
1310{
1311 struct rb_node *rb_node;
1312 struct mapping_node *node = NULL;
1313 struct reloc_control *rc = root->fs_info->reloc_ctl;
1314
1315 spin_lock(&rc->reloc_root_tree.lock);
1316 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1317 root->node->start);
1318 if (rb_node) {
1319 node = rb_entry(rb_node, struct mapping_node, rb_node);
1320 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1321 }
1322 spin_unlock(&rc->reloc_root_tree.lock);
1323
1324 if (!node)
1325 return;
1326 BUG_ON((struct btrfs_root *)node->data != root);
1327
1328 spin_lock(&root->fs_info->trans_lock);
1329 list_del_init(&root->root_list);
1330 spin_unlock(&root->fs_info->trans_lock);
1331 kfree(node);
1332}
1333
1334/*
1335 * helper to update the 'address of tree root -> reloc tree'
1336 * mapping
1337 */
1338static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1339{
1340 struct rb_node *rb_node;
1341 struct mapping_node *node = NULL;
1342 struct reloc_control *rc = root->fs_info->reloc_ctl;
1343
1344 spin_lock(&rc->reloc_root_tree.lock);
1345 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1346 root->node->start);
1347 if (rb_node) {
1348 node = rb_entry(rb_node, struct mapping_node, rb_node);
1349 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1350 }
1351 spin_unlock(&rc->reloc_root_tree.lock);
1352
1353 if (!node)
1354 return 0;
1355 BUG_ON((struct btrfs_root *)node->data != root);
1356
1357 spin_lock(&rc->reloc_root_tree.lock);
1358 node->bytenr = new_bytenr;
1359 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1360 node->bytenr, &node->rb_node);
1361 spin_unlock(&rc->reloc_root_tree.lock);
1362 if (rb_node)
1363 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1364 return 0;
1365}
1366
1367static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1368 struct btrfs_root *root, u64 objectid)
1369{
1370 struct btrfs_root *reloc_root;
1371 struct extent_buffer *eb;
1372 struct btrfs_root_item *root_item;
1373 struct btrfs_key root_key;
1374 u64 last_snap = 0;
1375 int ret;
1376
1377 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1378 BUG_ON(!root_item);
1379
1380 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1381 root_key.type = BTRFS_ROOT_ITEM_KEY;
1382 root_key.offset = objectid;
1383
1384 if (root->root_key.objectid == objectid) {
1385 /* called by btrfs_init_reloc_root */
1386 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1387 BTRFS_TREE_RELOC_OBJECTID);
1388 BUG_ON(ret);
1389
1390 last_snap = btrfs_root_last_snapshot(&root->root_item);
1391 btrfs_set_root_last_snapshot(&root->root_item,
1392 trans->transid - 1);
1393 } else {
1394 /*
1395 * called by btrfs_reloc_post_snapshot_hook.
1396 * the source tree is a reloc tree, all tree blocks
1397 * modified after it was created have RELOC flag
1398 * set in their headers. so it's OK to not update
1399 * the 'last_snapshot'.
1400 */
1401 ret = btrfs_copy_root(trans, root, root->node, &eb,
1402 BTRFS_TREE_RELOC_OBJECTID);
1403 BUG_ON(ret);
1404 }
1405
1406 memcpy(root_item, &root->root_item, sizeof(*root_item));
1407 btrfs_set_root_bytenr(root_item, eb->start);
1408 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1409 btrfs_set_root_generation(root_item, trans->transid);
1410
1411 if (root->root_key.objectid == objectid) {
1412 btrfs_set_root_refs(root_item, 0);
1413 memset(&root_item->drop_progress, 0,
1414 sizeof(struct btrfs_disk_key));
1415 root_item->drop_level = 0;
1416 /*
1417 * abuse rtransid, it is safe because it is impossible to
1418 * receive data into a relocation tree.
1419 */
1420 btrfs_set_root_rtransid(root_item, last_snap);
1421 btrfs_set_root_otransid(root_item, trans->transid);
1422 }
1423
1424 btrfs_tree_unlock(eb);
1425 free_extent_buffer(eb);
1426
1427 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1428 &root_key, root_item);
1429 BUG_ON(ret);
1430 kfree(root_item);
1431
1432 reloc_root = btrfs_read_fs_root(root->fs_info->tree_root, &root_key);
1433 BUG_ON(IS_ERR(reloc_root));
1434 reloc_root->last_trans = trans->transid;
1435 return reloc_root;
1436}
1437
1438/*
1439 * create reloc tree for a given fs tree. reloc tree is just a
1440 * snapshot of the fs tree with special root objectid.
1441 */
1442int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1443 struct btrfs_root *root)
1444{
1445 struct btrfs_root *reloc_root;
1446 struct reloc_control *rc = root->fs_info->reloc_ctl;
1447 struct btrfs_block_rsv *rsv;
1448 int clear_rsv = 0;
1449 int ret;
1450
1451 if (root->reloc_root) {
1452 reloc_root = root->reloc_root;
1453 reloc_root->last_trans = trans->transid;
1454 return 0;
1455 }
1456
1457 if (!rc || !rc->create_reloc_tree ||
1458 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1459 return 0;
1460
1461 if (!trans->reloc_reserved) {
1462 rsv = trans->block_rsv;
1463 trans->block_rsv = rc->block_rsv;
1464 clear_rsv = 1;
1465 }
1466 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1467 if (clear_rsv)
1468 trans->block_rsv = rsv;
1469
1470 ret = __add_reloc_root(reloc_root);
1471 BUG_ON(ret < 0);
1472 root->reloc_root = reloc_root;
1473 return 0;
1474}
1475
1476/*
1477 * update root item of reloc tree
1478 */
1479int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1480 struct btrfs_root *root)
1481{
1482 struct btrfs_root *reloc_root;
1483 struct btrfs_root_item *root_item;
1484 int ret;
1485
1486 if (!root->reloc_root)
1487 goto out;
1488
1489 reloc_root = root->reloc_root;
1490 root_item = &reloc_root->root_item;
1491
1492 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1493 btrfs_root_refs(root_item) == 0) {
1494 root->reloc_root = NULL;
1495 __del_reloc_root(reloc_root);
1496 }
1497
1498 if (reloc_root->commit_root != reloc_root->node) {
1499 btrfs_set_root_node(root_item, reloc_root->node);
1500 free_extent_buffer(reloc_root->commit_root);
1501 reloc_root->commit_root = btrfs_root_node(reloc_root);
1502 }
1503
1504 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1505 &reloc_root->root_key, root_item);
1506 BUG_ON(ret);
1507
1508out:
1509 return 0;
1510}
1511
1512/*
1513 * helper to find first cached inode with inode number >= objectid
1514 * in a subvolume
1515 */
1516static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1517{
1518 struct rb_node *node;
1519 struct rb_node *prev;
1520 struct btrfs_inode *entry;
1521 struct inode *inode;
1522
1523 spin_lock(&root->inode_lock);
1524again:
1525 node = root->inode_tree.rb_node;
1526 prev = NULL;
1527 while (node) {
1528 prev = node;
1529 entry = rb_entry(node, struct btrfs_inode, rb_node);
1530
1531 if (objectid < btrfs_ino(&entry->vfs_inode))
1532 node = node->rb_left;
1533 else if (objectid > btrfs_ino(&entry->vfs_inode))
1534 node = node->rb_right;
1535 else
1536 break;
1537 }
1538 if (!node) {
1539 while (prev) {
1540 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1541 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1542 node = prev;
1543 break;
1544 }
1545 prev = rb_next(prev);
1546 }
1547 }
1548 while (node) {
1549 entry = rb_entry(node, struct btrfs_inode, rb_node);
1550 inode = igrab(&entry->vfs_inode);
1551 if (inode) {
1552 spin_unlock(&root->inode_lock);
1553 return inode;
1554 }
1555
1556 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1557 if (cond_resched_lock(&root->inode_lock))
1558 goto again;
1559
1560 node = rb_next(node);
1561 }
1562 spin_unlock(&root->inode_lock);
1563 return NULL;
1564}
1565
1566static int in_block_group(u64 bytenr,
1567 struct btrfs_block_group_cache *block_group)
1568{
1569 if (bytenr >= block_group->key.objectid &&
1570 bytenr < block_group->key.objectid + block_group->key.offset)
1571 return 1;
1572 return 0;
1573}
1574
1575/*
1576 * get new location of data
1577 */
1578static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1579 u64 bytenr, u64 num_bytes)
1580{
1581 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1582 struct btrfs_path *path;
1583 struct btrfs_file_extent_item *fi;
1584 struct extent_buffer *leaf;
1585 int ret;
1586
1587 path = btrfs_alloc_path();
1588 if (!path)
1589 return -ENOMEM;
1590
1591 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1592 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1593 bytenr, 0);
1594 if (ret < 0)
1595 goto out;
1596 if (ret > 0) {
1597 ret = -ENOENT;
1598 goto out;
1599 }
1600
1601 leaf = path->nodes[0];
1602 fi = btrfs_item_ptr(leaf, path->slots[0],
1603 struct btrfs_file_extent_item);
1604
1605 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1606 btrfs_file_extent_compression(leaf, fi) ||
1607 btrfs_file_extent_encryption(leaf, fi) ||
1608 btrfs_file_extent_other_encoding(leaf, fi));
1609
1610 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1611 ret = -EINVAL;
1612 goto out;
1613 }
1614
1615 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1616 ret = 0;
1617out:
1618 btrfs_free_path(path);
1619 return ret;
1620}
1621
1622/*
1623 * update file extent items in the tree leaf to point to
1624 * the new locations.
1625 */
1626static noinline_for_stack
1627int replace_file_extents(struct btrfs_trans_handle *trans,
1628 struct reloc_control *rc,
1629 struct btrfs_root *root,
1630 struct extent_buffer *leaf)
1631{
1632 struct btrfs_key key;
1633 struct btrfs_file_extent_item *fi;
1634 struct inode *inode = NULL;
1635 u64 parent;
1636 u64 bytenr;
1637 u64 new_bytenr = 0;
1638 u64 num_bytes;
1639 u64 end;
1640 u32 nritems;
1641 u32 i;
1642 int ret = 0;
1643 int first = 1;
1644 int dirty = 0;
1645
1646 if (rc->stage != UPDATE_DATA_PTRS)
1647 return 0;
1648
1649 /* reloc trees always use full backref */
1650 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1651 parent = leaf->start;
1652 else
1653 parent = 0;
1654
1655 nritems = btrfs_header_nritems(leaf);
1656 for (i = 0; i < nritems; i++) {
1657 cond_resched();
1658 btrfs_item_key_to_cpu(leaf, &key, i);
1659 if (key.type != BTRFS_EXTENT_DATA_KEY)
1660 continue;
1661 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1662 if (btrfs_file_extent_type(leaf, fi) ==
1663 BTRFS_FILE_EXTENT_INLINE)
1664 continue;
1665 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1666 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1667 if (bytenr == 0)
1668 continue;
1669 if (!in_block_group(bytenr, rc->block_group))
1670 continue;
1671
1672 /*
1673 * if we are modifying block in fs tree, wait for readpage
1674 * to complete and drop the extent cache
1675 */
1676 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1677 if (first) {
1678 inode = find_next_inode(root, key.objectid);
1679 first = 0;
1680 } else if (inode && btrfs_ino(inode) < key.objectid) {
1681 btrfs_add_delayed_iput(inode);
1682 inode = find_next_inode(root, key.objectid);
1683 }
1684 if (inode && btrfs_ino(inode) == key.objectid) {
1685 end = key.offset +
1686 btrfs_file_extent_num_bytes(leaf, fi);
1687 WARN_ON(!IS_ALIGNED(key.offset,
1688 root->sectorsize));
1689 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1690 end--;
1691 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1692 key.offset, end);
1693 if (!ret)
1694 continue;
1695
1696 btrfs_drop_extent_cache(inode, key.offset, end,
1697 1);
1698 unlock_extent(&BTRFS_I(inode)->io_tree,
1699 key.offset, end);
1700 }
1701 }
1702
1703 ret = get_new_location(rc->data_inode, &new_bytenr,
1704 bytenr, num_bytes);
1705 if (ret) {
1706 /*
1707 * Don't have to abort since we've not changed anything
1708 * in the file extent yet.
1709 */
1710 break;
1711 }
1712
1713 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1714 dirty = 1;
1715
1716 key.offset -= btrfs_file_extent_offset(leaf, fi);
1717 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1718 num_bytes, parent,
1719 btrfs_header_owner(leaf),
1720 key.objectid, key.offset);
1721 if (ret) {
1722 btrfs_abort_transaction(trans, root, ret);
1723 break;
1724 }
1725
1726 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1727 parent, btrfs_header_owner(leaf),
1728 key.objectid, key.offset);
1729 if (ret) {
1730 btrfs_abort_transaction(trans, root, ret);
1731 break;
1732 }
1733 }
1734 if (dirty)
1735 btrfs_mark_buffer_dirty(leaf);
1736 if (inode)
1737 btrfs_add_delayed_iput(inode);
1738 return ret;
1739}
1740
1741static noinline_for_stack
1742int memcmp_node_keys(struct extent_buffer *eb, int slot,
1743 struct btrfs_path *path, int level)
1744{
1745 struct btrfs_disk_key key1;
1746 struct btrfs_disk_key key2;
1747 btrfs_node_key(eb, &key1, slot);
1748 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1749 return memcmp(&key1, &key2, sizeof(key1));
1750}
1751
1752/*
1753 * try to replace tree blocks in fs tree with the new blocks
1754 * in reloc tree. tree blocks haven't been modified since the
1755 * reloc tree was create can be replaced.
1756 *
1757 * if a block was replaced, level of the block + 1 is returned.
1758 * if no block got replaced, 0 is returned. if there are other
1759 * errors, a negative error number is returned.
1760 */
1761static noinline_for_stack
1762int replace_path(struct btrfs_trans_handle *trans,
1763 struct btrfs_root *dest, struct btrfs_root *src,
1764 struct btrfs_path *path, struct btrfs_key *next_key,
1765 int lowest_level, int max_level)
1766{
1767 struct extent_buffer *eb;
1768 struct extent_buffer *parent;
1769 struct btrfs_key key;
1770 u64 old_bytenr;
1771 u64 new_bytenr;
1772 u64 old_ptr_gen;
1773 u64 new_ptr_gen;
1774 u64 last_snapshot;
1775 u32 blocksize;
1776 int cow = 0;
1777 int level;
1778 int ret;
1779 int slot;
1780
1781 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1782 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1783
1784 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1785again:
1786 slot = path->slots[lowest_level];
1787 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1788
1789 eb = btrfs_lock_root_node(dest);
1790 btrfs_set_lock_blocking(eb);
1791 level = btrfs_header_level(eb);
1792
1793 if (level < lowest_level) {
1794 btrfs_tree_unlock(eb);
1795 free_extent_buffer(eb);
1796 return 0;
1797 }
1798
1799 if (cow) {
1800 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1801 BUG_ON(ret);
1802 }
1803 btrfs_set_lock_blocking(eb);
1804
1805 if (next_key) {
1806 next_key->objectid = (u64)-1;
1807 next_key->type = (u8)-1;
1808 next_key->offset = (u64)-1;
1809 }
1810
1811 parent = eb;
1812 while (1) {
1813 level = btrfs_header_level(parent);
1814 BUG_ON(level < lowest_level);
1815
1816 ret = btrfs_bin_search(parent, &key, level, &slot);
1817 if (ret && slot > 0)
1818 slot--;
1819
1820 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1821 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1822
1823 old_bytenr = btrfs_node_blockptr(parent, slot);
1824 blocksize = dest->nodesize;
1825 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1826
1827 if (level <= max_level) {
1828 eb = path->nodes[level];
1829 new_bytenr = btrfs_node_blockptr(eb,
1830 path->slots[level]);
1831 new_ptr_gen = btrfs_node_ptr_generation(eb,
1832 path->slots[level]);
1833 } else {
1834 new_bytenr = 0;
1835 new_ptr_gen = 0;
1836 }
1837
1838 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1839 ret = level;
1840 break;
1841 }
1842
1843 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1844 memcmp_node_keys(parent, slot, path, level)) {
1845 if (level <= lowest_level) {
1846 ret = 0;
1847 break;
1848 }
1849
1850 eb = read_tree_block(dest, old_bytenr, old_ptr_gen);
1851 if (IS_ERR(eb)) {
1852 ret = PTR_ERR(eb);
1853 break;
1854 } else if (!extent_buffer_uptodate(eb)) {
1855 ret = -EIO;
1856 free_extent_buffer(eb);
1857 break;
1858 }
1859 btrfs_tree_lock(eb);
1860 if (cow) {
1861 ret = btrfs_cow_block(trans, dest, eb, parent,
1862 slot, &eb);
1863 BUG_ON(ret);
1864 }
1865 btrfs_set_lock_blocking(eb);
1866
1867 btrfs_tree_unlock(parent);
1868 free_extent_buffer(parent);
1869
1870 parent = eb;
1871 continue;
1872 }
1873
1874 if (!cow) {
1875 btrfs_tree_unlock(parent);
1876 free_extent_buffer(parent);
1877 cow = 1;
1878 goto again;
1879 }
1880
1881 btrfs_node_key_to_cpu(path->nodes[level], &key,
1882 path->slots[level]);
1883 btrfs_release_path(path);
1884
1885 path->lowest_level = level;
1886 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1887 path->lowest_level = 0;
1888 BUG_ON(ret);
1889
1890 /*
1891 * swap blocks in fs tree and reloc tree.
1892 */
1893 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1894 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1895 btrfs_mark_buffer_dirty(parent);
1896
1897 btrfs_set_node_blockptr(path->nodes[level],
1898 path->slots[level], old_bytenr);
1899 btrfs_set_node_ptr_generation(path->nodes[level],
1900 path->slots[level], old_ptr_gen);
1901 btrfs_mark_buffer_dirty(path->nodes[level]);
1902
1903 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1904 path->nodes[level]->start,
1905 src->root_key.objectid, level - 1, 0);
1906 BUG_ON(ret);
1907 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1908 0, dest->root_key.objectid, level - 1,
1909 0);
1910 BUG_ON(ret);
1911
1912 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1913 path->nodes[level]->start,
1914 src->root_key.objectid, level - 1, 0);
1915 BUG_ON(ret);
1916
1917 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1918 0, dest->root_key.objectid, level - 1,
1919 0);
1920 BUG_ON(ret);
1921
1922 btrfs_unlock_up_safe(path, 0);
1923
1924 ret = level;
1925 break;
1926 }
1927 btrfs_tree_unlock(parent);
1928 free_extent_buffer(parent);
1929 return ret;
1930}
1931
1932/*
1933 * helper to find next relocated block in reloc tree
1934 */
1935static noinline_for_stack
1936int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1937 int *level)
1938{
1939 struct extent_buffer *eb;
1940 int i;
1941 u64 last_snapshot;
1942 u32 nritems;
1943
1944 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1945
1946 for (i = 0; i < *level; i++) {
1947 free_extent_buffer(path->nodes[i]);
1948 path->nodes[i] = NULL;
1949 }
1950
1951 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1952 eb = path->nodes[i];
1953 nritems = btrfs_header_nritems(eb);
1954 while (path->slots[i] + 1 < nritems) {
1955 path->slots[i]++;
1956 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1957 last_snapshot)
1958 continue;
1959
1960 *level = i;
1961 return 0;
1962 }
1963 free_extent_buffer(path->nodes[i]);
1964 path->nodes[i] = NULL;
1965 }
1966 return 1;
1967}
1968
1969/*
1970 * walk down reloc tree to find relocated block of lowest level
1971 */
1972static noinline_for_stack
1973int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1974 int *level)
1975{
1976 struct extent_buffer *eb = NULL;
1977 int i;
1978 u64 bytenr;
1979 u64 ptr_gen = 0;
1980 u64 last_snapshot;
1981 u32 nritems;
1982
1983 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1984
1985 for (i = *level; i > 0; i--) {
1986 eb = path->nodes[i];
1987 nritems = btrfs_header_nritems(eb);
1988 while (path->slots[i] < nritems) {
1989 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1990 if (ptr_gen > last_snapshot)
1991 break;
1992 path->slots[i]++;
1993 }
1994 if (path->slots[i] >= nritems) {
1995 if (i == *level)
1996 break;
1997 *level = i + 1;
1998 return 0;
1999 }
2000 if (i == 1) {
2001 *level = i;
2002 return 0;
2003 }
2004
2005 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2006 eb = read_tree_block(root, bytenr, ptr_gen);
2007 if (IS_ERR(eb)) {
2008 return PTR_ERR(eb);
2009 } else if (!extent_buffer_uptodate(eb)) {
2010 free_extent_buffer(eb);
2011 return -EIO;
2012 }
2013 BUG_ON(btrfs_header_level(eb) != i - 1);
2014 path->nodes[i - 1] = eb;
2015 path->slots[i - 1] = 0;
2016 }
2017 return 1;
2018}
2019
2020/*
2021 * invalidate extent cache for file extents whose key in range of
2022 * [min_key, max_key)
2023 */
2024static int invalidate_extent_cache(struct btrfs_root *root,
2025 struct btrfs_key *min_key,
2026 struct btrfs_key *max_key)
2027{
2028 struct inode *inode = NULL;
2029 u64 objectid;
2030 u64 start, end;
2031 u64 ino;
2032
2033 objectid = min_key->objectid;
2034 while (1) {
2035 cond_resched();
2036 iput(inode);
2037
2038 if (objectid > max_key->objectid)
2039 break;
2040
2041 inode = find_next_inode(root, objectid);
2042 if (!inode)
2043 break;
2044 ino = btrfs_ino(inode);
2045
2046 if (ino > max_key->objectid) {
2047 iput(inode);
2048 break;
2049 }
2050
2051 objectid = ino + 1;
2052 if (!S_ISREG(inode->i_mode))
2053 continue;
2054
2055 if (unlikely(min_key->objectid == ino)) {
2056 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2057 continue;
2058 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2059 start = 0;
2060 else {
2061 start = min_key->offset;
2062 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
2063 }
2064 } else {
2065 start = 0;
2066 }
2067
2068 if (unlikely(max_key->objectid == ino)) {
2069 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2070 continue;
2071 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2072 end = (u64)-1;
2073 } else {
2074 if (max_key->offset == 0)
2075 continue;
2076 end = max_key->offset;
2077 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
2078 end--;
2079 }
2080 } else {
2081 end = (u64)-1;
2082 }
2083
2084 /* the lock_extent waits for readpage to complete */
2085 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2086 btrfs_drop_extent_cache(inode, start, end, 1);
2087 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2088 }
2089 return 0;
2090}
2091
2092static int find_next_key(struct btrfs_path *path, int level,
2093 struct btrfs_key *key)
2094
2095{
2096 while (level < BTRFS_MAX_LEVEL) {
2097 if (!path->nodes[level])
2098 break;
2099 if (path->slots[level] + 1 <
2100 btrfs_header_nritems(path->nodes[level])) {
2101 btrfs_node_key_to_cpu(path->nodes[level], key,
2102 path->slots[level] + 1);
2103 return 0;
2104 }
2105 level++;
2106 }
2107 return 1;
2108}
2109
2110/*
2111 * merge the relocated tree blocks in reloc tree with corresponding
2112 * fs tree.
2113 */
2114static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2115 struct btrfs_root *root)
2116{
2117 LIST_HEAD(inode_list);
2118 struct btrfs_key key;
2119 struct btrfs_key next_key;
2120 struct btrfs_trans_handle *trans = NULL;
2121 struct btrfs_root *reloc_root;
2122 struct btrfs_root_item *root_item;
2123 struct btrfs_path *path;
2124 struct extent_buffer *leaf;
2125 int level;
2126 int max_level;
2127 int replaced = 0;
2128 int ret;
2129 int err = 0;
2130 u32 min_reserved;
2131
2132 path = btrfs_alloc_path();
2133 if (!path)
2134 return -ENOMEM;
2135 path->reada = READA_FORWARD;
2136
2137 reloc_root = root->reloc_root;
2138 root_item = &reloc_root->root_item;
2139
2140 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2141 level = btrfs_root_level(root_item);
2142 extent_buffer_get(reloc_root->node);
2143 path->nodes[level] = reloc_root->node;
2144 path->slots[level] = 0;
2145 } else {
2146 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2147
2148 level = root_item->drop_level;
2149 BUG_ON(level == 0);
2150 path->lowest_level = level;
2151 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2152 path->lowest_level = 0;
2153 if (ret < 0) {
2154 btrfs_free_path(path);
2155 return ret;
2156 }
2157
2158 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2159 path->slots[level]);
2160 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2161
2162 btrfs_unlock_up_safe(path, 0);
2163 }
2164
2165 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2166 memset(&next_key, 0, sizeof(next_key));
2167
2168 while (1) {
2169 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2170 BTRFS_RESERVE_FLUSH_ALL);
2171 if (ret) {
2172 err = ret;
2173 goto out;
2174 }
2175 trans = btrfs_start_transaction(root, 0);
2176 if (IS_ERR(trans)) {
2177 err = PTR_ERR(trans);
2178 trans = NULL;
2179 goto out;
2180 }
2181 trans->block_rsv = rc->block_rsv;
2182
2183 replaced = 0;
2184 max_level = level;
2185
2186 ret = walk_down_reloc_tree(reloc_root, path, &level);
2187 if (ret < 0) {
2188 err = ret;
2189 goto out;
2190 }
2191 if (ret > 0)
2192 break;
2193
2194 if (!find_next_key(path, level, &key) &&
2195 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2196 ret = 0;
2197 } else {
2198 ret = replace_path(trans, root, reloc_root, path,
2199 &next_key, level, max_level);
2200 }
2201 if (ret < 0) {
2202 err = ret;
2203 goto out;
2204 }
2205
2206 if (ret > 0) {
2207 level = ret;
2208 btrfs_node_key_to_cpu(path->nodes[level], &key,
2209 path->slots[level]);
2210 replaced = 1;
2211 }
2212
2213 ret = walk_up_reloc_tree(reloc_root, path, &level);
2214 if (ret > 0)
2215 break;
2216
2217 BUG_ON(level == 0);
2218 /*
2219 * save the merging progress in the drop_progress.
2220 * this is OK since root refs == 1 in this case.
2221 */
2222 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2223 path->slots[level]);
2224 root_item->drop_level = level;
2225
2226 btrfs_end_transaction_throttle(trans, root);
2227 trans = NULL;
2228
2229 btrfs_btree_balance_dirty(root);
2230
2231 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2232 invalidate_extent_cache(root, &key, &next_key);
2233 }
2234
2235 /*
2236 * handle the case only one block in the fs tree need to be
2237 * relocated and the block is tree root.
2238 */
2239 leaf = btrfs_lock_root_node(root);
2240 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2241 btrfs_tree_unlock(leaf);
2242 free_extent_buffer(leaf);
2243 if (ret < 0)
2244 err = ret;
2245out:
2246 btrfs_free_path(path);
2247
2248 if (err == 0) {
2249 memset(&root_item->drop_progress, 0,
2250 sizeof(root_item->drop_progress));
2251 root_item->drop_level = 0;
2252 btrfs_set_root_refs(root_item, 0);
2253 btrfs_update_reloc_root(trans, root);
2254 }
2255
2256 if (trans)
2257 btrfs_end_transaction_throttle(trans, root);
2258
2259 btrfs_btree_balance_dirty(root);
2260
2261 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2262 invalidate_extent_cache(root, &key, &next_key);
2263
2264 return err;
2265}
2266
2267static noinline_for_stack
2268int prepare_to_merge(struct reloc_control *rc, int err)
2269{
2270 struct btrfs_root *root = rc->extent_root;
2271 struct btrfs_root *reloc_root;
2272 struct btrfs_trans_handle *trans;
2273 LIST_HEAD(reloc_roots);
2274 u64 num_bytes = 0;
2275 int ret;
2276
2277 mutex_lock(&root->fs_info->reloc_mutex);
2278 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2279 rc->merging_rsv_size += rc->nodes_relocated * 2;
2280 mutex_unlock(&root->fs_info->reloc_mutex);
2281
2282again:
2283 if (!err) {
2284 num_bytes = rc->merging_rsv_size;
2285 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2286 BTRFS_RESERVE_FLUSH_ALL);
2287 if (ret)
2288 err = ret;
2289 }
2290
2291 trans = btrfs_join_transaction(rc->extent_root);
2292 if (IS_ERR(trans)) {
2293 if (!err)
2294 btrfs_block_rsv_release(rc->extent_root,
2295 rc->block_rsv, num_bytes);
2296 return PTR_ERR(trans);
2297 }
2298
2299 if (!err) {
2300 if (num_bytes != rc->merging_rsv_size) {
2301 btrfs_end_transaction(trans, rc->extent_root);
2302 btrfs_block_rsv_release(rc->extent_root,
2303 rc->block_rsv, num_bytes);
2304 goto again;
2305 }
2306 }
2307
2308 rc->merge_reloc_tree = 1;
2309
2310 while (!list_empty(&rc->reloc_roots)) {
2311 reloc_root = list_entry(rc->reloc_roots.next,
2312 struct btrfs_root, root_list);
2313 list_del_init(&reloc_root->root_list);
2314
2315 root = read_fs_root(reloc_root->fs_info,
2316 reloc_root->root_key.offset);
2317 BUG_ON(IS_ERR(root));
2318 BUG_ON(root->reloc_root != reloc_root);
2319
2320 /*
2321 * set reference count to 1, so btrfs_recover_relocation
2322 * knows it should resumes merging
2323 */
2324 if (!err)
2325 btrfs_set_root_refs(&reloc_root->root_item, 1);
2326 btrfs_update_reloc_root(trans, root);
2327
2328 list_add(&reloc_root->root_list, &reloc_roots);
2329 }
2330
2331 list_splice(&reloc_roots, &rc->reloc_roots);
2332
2333 if (!err)
2334 btrfs_commit_transaction(trans, rc->extent_root);
2335 else
2336 btrfs_end_transaction(trans, rc->extent_root);
2337 return err;
2338}
2339
2340static noinline_for_stack
2341void free_reloc_roots(struct list_head *list)
2342{
2343 struct btrfs_root *reloc_root;
2344
2345 while (!list_empty(list)) {
2346 reloc_root = list_entry(list->next, struct btrfs_root,
2347 root_list);
2348 __del_reloc_root(reloc_root);
2349 }
2350}
2351
2352static noinline_for_stack
2353void merge_reloc_roots(struct reloc_control *rc)
2354{
2355 struct btrfs_root *root;
2356 struct btrfs_root *reloc_root;
2357 u64 last_snap;
2358 u64 otransid;
2359 u64 objectid;
2360 LIST_HEAD(reloc_roots);
2361 int found = 0;
2362 int ret = 0;
2363again:
2364 root = rc->extent_root;
2365
2366 /*
2367 * this serializes us with btrfs_record_root_in_transaction,
2368 * we have to make sure nobody is in the middle of
2369 * adding their roots to the list while we are
2370 * doing this splice
2371 */
2372 mutex_lock(&root->fs_info->reloc_mutex);
2373 list_splice_init(&rc->reloc_roots, &reloc_roots);
2374 mutex_unlock(&root->fs_info->reloc_mutex);
2375
2376 while (!list_empty(&reloc_roots)) {
2377 found = 1;
2378 reloc_root = list_entry(reloc_roots.next,
2379 struct btrfs_root, root_list);
2380
2381 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2382 root = read_fs_root(reloc_root->fs_info,
2383 reloc_root->root_key.offset);
2384 BUG_ON(IS_ERR(root));
2385 BUG_ON(root->reloc_root != reloc_root);
2386
2387 ret = merge_reloc_root(rc, root);
2388 if (ret) {
2389 if (list_empty(&reloc_root->root_list))
2390 list_add_tail(&reloc_root->root_list,
2391 &reloc_roots);
2392 goto out;
2393 }
2394 } else {
2395 list_del_init(&reloc_root->root_list);
2396 }
2397
2398 /*
2399 * we keep the old last snapshod transid in rtranid when we
2400 * created the relocation tree.
2401 */
2402 last_snap = btrfs_root_rtransid(&reloc_root->root_item);
2403 otransid = btrfs_root_otransid(&reloc_root->root_item);
2404 objectid = reloc_root->root_key.offset;
2405
2406 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2407 if (ret < 0) {
2408 if (list_empty(&reloc_root->root_list))
2409 list_add_tail(&reloc_root->root_list,
2410 &reloc_roots);
2411 goto out;
2412 }
2413 }
2414
2415 if (found) {
2416 found = 0;
2417 goto again;
2418 }
2419out:
2420 if (ret) {
2421 btrfs_std_error(root->fs_info, ret, NULL);
2422 if (!list_empty(&reloc_roots))
2423 free_reloc_roots(&reloc_roots);
2424
2425 /* new reloc root may be added */
2426 mutex_lock(&root->fs_info->reloc_mutex);
2427 list_splice_init(&rc->reloc_roots, &reloc_roots);
2428 mutex_unlock(&root->fs_info->reloc_mutex);
2429 if (!list_empty(&reloc_roots))
2430 free_reloc_roots(&reloc_roots);
2431 }
2432
2433 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2434}
2435
2436static void free_block_list(struct rb_root *blocks)
2437{
2438 struct tree_block *block;
2439 struct rb_node *rb_node;
2440 while ((rb_node = rb_first(blocks))) {
2441 block = rb_entry(rb_node, struct tree_block, rb_node);
2442 rb_erase(rb_node, blocks);
2443 kfree(block);
2444 }
2445}
2446
2447static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2448 struct btrfs_root *reloc_root)
2449{
2450 struct btrfs_root *root;
2451
2452 if (reloc_root->last_trans == trans->transid)
2453 return 0;
2454
2455 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2456 BUG_ON(IS_ERR(root));
2457 BUG_ON(root->reloc_root != reloc_root);
2458
2459 return btrfs_record_root_in_trans(trans, root);
2460}
2461
2462static noinline_for_stack
2463struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2464 struct reloc_control *rc,
2465 struct backref_node *node,
2466 struct backref_edge *edges[])
2467{
2468 struct backref_node *next;
2469 struct btrfs_root *root;
2470 int index = 0;
2471
2472 next = node;
2473 while (1) {
2474 cond_resched();
2475 next = walk_up_backref(next, edges, &index);
2476 root = next->root;
2477 BUG_ON(!root);
2478 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2479
2480 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2481 record_reloc_root_in_trans(trans, root);
2482 break;
2483 }
2484
2485 btrfs_record_root_in_trans(trans, root);
2486 root = root->reloc_root;
2487
2488 if (next->new_bytenr != root->node->start) {
2489 BUG_ON(next->new_bytenr);
2490 BUG_ON(!list_empty(&next->list));
2491 next->new_bytenr = root->node->start;
2492 next->root = root;
2493 list_add_tail(&next->list,
2494 &rc->backref_cache.changed);
2495 __mark_block_processed(rc, next);
2496 break;
2497 }
2498
2499 WARN_ON(1);
2500 root = NULL;
2501 next = walk_down_backref(edges, &index);
2502 if (!next || next->level <= node->level)
2503 break;
2504 }
2505 if (!root)
2506 return NULL;
2507
2508 next = node;
2509 /* setup backref node path for btrfs_reloc_cow_block */
2510 while (1) {
2511 rc->backref_cache.path[next->level] = next;
2512 if (--index < 0)
2513 break;
2514 next = edges[index]->node[UPPER];
2515 }
2516 return root;
2517}
2518
2519/*
2520 * select a tree root for relocation. return NULL if the block
2521 * is reference counted. we should use do_relocation() in this
2522 * case. return a tree root pointer if the block isn't reference
2523 * counted. return -ENOENT if the block is root of reloc tree.
2524 */
2525static noinline_for_stack
2526struct btrfs_root *select_one_root(struct backref_node *node)
2527{
2528 struct backref_node *next;
2529 struct btrfs_root *root;
2530 struct btrfs_root *fs_root = NULL;
2531 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2532 int index = 0;
2533
2534 next = node;
2535 while (1) {
2536 cond_resched();
2537 next = walk_up_backref(next, edges, &index);
2538 root = next->root;
2539 BUG_ON(!root);
2540
2541 /* no other choice for non-references counted tree */
2542 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2543 return root;
2544
2545 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2546 fs_root = root;
2547
2548 if (next != node)
2549 return NULL;
2550
2551 next = walk_down_backref(edges, &index);
2552 if (!next || next->level <= node->level)
2553 break;
2554 }
2555
2556 if (!fs_root)
2557 return ERR_PTR(-ENOENT);
2558 return fs_root;
2559}
2560
2561static noinline_for_stack
2562u64 calcu_metadata_size(struct reloc_control *rc,
2563 struct backref_node *node, int reserve)
2564{
2565 struct backref_node *next = node;
2566 struct backref_edge *edge;
2567 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2568 u64 num_bytes = 0;
2569 int index = 0;
2570
2571 BUG_ON(reserve && node->processed);
2572
2573 while (next) {
2574 cond_resched();
2575 while (1) {
2576 if (next->processed && (reserve || next != node))
2577 break;
2578
2579 num_bytes += rc->extent_root->nodesize;
2580
2581 if (list_empty(&next->upper))
2582 break;
2583
2584 edge = list_entry(next->upper.next,
2585 struct backref_edge, list[LOWER]);
2586 edges[index++] = edge;
2587 next = edge->node[UPPER];
2588 }
2589 next = walk_down_backref(edges, &index);
2590 }
2591 return num_bytes;
2592}
2593
2594static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2595 struct reloc_control *rc,
2596 struct backref_node *node)
2597{
2598 struct btrfs_root *root = rc->extent_root;
2599 u64 num_bytes;
2600 int ret;
2601 u64 tmp;
2602
2603 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2604
2605 trans->block_rsv = rc->block_rsv;
2606 rc->reserved_bytes += num_bytes;
2607 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2608 BTRFS_RESERVE_FLUSH_ALL);
2609 if (ret) {
2610 if (ret == -EAGAIN) {
2611 tmp = rc->extent_root->nodesize *
2612 RELOCATION_RESERVED_NODES;
2613 while (tmp <= rc->reserved_bytes)
2614 tmp <<= 1;
2615 /*
2616 * only one thread can access block_rsv at this point,
2617 * so we don't need hold lock to protect block_rsv.
2618 * we expand more reservation size here to allow enough
2619 * space for relocation and we will return eailer in
2620 * enospc case.
2621 */
2622 rc->block_rsv->size = tmp + rc->extent_root->nodesize *
2623 RELOCATION_RESERVED_NODES;
2624 }
2625 return ret;
2626 }
2627
2628 return 0;
2629}
2630
2631/*
2632 * relocate a block tree, and then update pointers in upper level
2633 * blocks that reference the block to point to the new location.
2634 *
2635 * if called by link_to_upper, the block has already been relocated.
2636 * in that case this function just updates pointers.
2637 */
2638static int do_relocation(struct btrfs_trans_handle *trans,
2639 struct reloc_control *rc,
2640 struct backref_node *node,
2641 struct btrfs_key *key,
2642 struct btrfs_path *path, int lowest)
2643{
2644 struct backref_node *upper;
2645 struct backref_edge *edge;
2646 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2647 struct btrfs_root *root;
2648 struct extent_buffer *eb;
2649 u32 blocksize;
2650 u64 bytenr;
2651 u64 generation;
2652 int slot;
2653 int ret;
2654 int err = 0;
2655
2656 BUG_ON(lowest && node->eb);
2657
2658 path->lowest_level = node->level + 1;
2659 rc->backref_cache.path[node->level] = node;
2660 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2661 cond_resched();
2662
2663 upper = edge->node[UPPER];
2664 root = select_reloc_root(trans, rc, upper, edges);
2665 BUG_ON(!root);
2666
2667 if (upper->eb && !upper->locked) {
2668 if (!lowest) {
2669 ret = btrfs_bin_search(upper->eb, key,
2670 upper->level, &slot);
2671 BUG_ON(ret);
2672 bytenr = btrfs_node_blockptr(upper->eb, slot);
2673 if (node->eb->start == bytenr)
2674 goto next;
2675 }
2676 drop_node_buffer(upper);
2677 }
2678
2679 if (!upper->eb) {
2680 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2681 if (ret < 0) {
2682 err = ret;
2683 break;
2684 }
2685 BUG_ON(ret > 0);
2686
2687 if (!upper->eb) {
2688 upper->eb = path->nodes[upper->level];
2689 path->nodes[upper->level] = NULL;
2690 } else {
2691 BUG_ON(upper->eb != path->nodes[upper->level]);
2692 }
2693
2694 upper->locked = 1;
2695 path->locks[upper->level] = 0;
2696
2697 slot = path->slots[upper->level];
2698 btrfs_release_path(path);
2699 } else {
2700 ret = btrfs_bin_search(upper->eb, key, upper->level,
2701 &slot);
2702 BUG_ON(ret);
2703 }
2704
2705 bytenr = btrfs_node_blockptr(upper->eb, slot);
2706 if (lowest) {
2707 BUG_ON(bytenr != node->bytenr);
2708 } else {
2709 if (node->eb->start == bytenr)
2710 goto next;
2711 }
2712
2713 blocksize = root->nodesize;
2714 generation = btrfs_node_ptr_generation(upper->eb, slot);
2715 eb = read_tree_block(root, bytenr, generation);
2716 if (IS_ERR(eb)) {
2717 err = PTR_ERR(eb);
2718 goto next;
2719 } else if (!extent_buffer_uptodate(eb)) {
2720 free_extent_buffer(eb);
2721 err = -EIO;
2722 goto next;
2723 }
2724 btrfs_tree_lock(eb);
2725 btrfs_set_lock_blocking(eb);
2726
2727 if (!node->eb) {
2728 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2729 slot, &eb);
2730 btrfs_tree_unlock(eb);
2731 free_extent_buffer(eb);
2732 if (ret < 0) {
2733 err = ret;
2734 goto next;
2735 }
2736 BUG_ON(node->eb != eb);
2737 } else {
2738 btrfs_set_node_blockptr(upper->eb, slot,
2739 node->eb->start);
2740 btrfs_set_node_ptr_generation(upper->eb, slot,
2741 trans->transid);
2742 btrfs_mark_buffer_dirty(upper->eb);
2743
2744 ret = btrfs_inc_extent_ref(trans, root,
2745 node->eb->start, blocksize,
2746 upper->eb->start,
2747 btrfs_header_owner(upper->eb),
2748 node->level, 0);
2749 BUG_ON(ret);
2750
2751 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2752 BUG_ON(ret);
2753 }
2754next:
2755 if (!upper->pending)
2756 drop_node_buffer(upper);
2757 else
2758 unlock_node_buffer(upper);
2759 if (err)
2760 break;
2761 }
2762
2763 if (!err && node->pending) {
2764 drop_node_buffer(node);
2765 list_move_tail(&node->list, &rc->backref_cache.changed);
2766 node->pending = 0;
2767 }
2768
2769 path->lowest_level = 0;
2770 BUG_ON(err == -ENOSPC);
2771 return err;
2772}
2773
2774static int link_to_upper(struct btrfs_trans_handle *trans,
2775 struct reloc_control *rc,
2776 struct backref_node *node,
2777 struct btrfs_path *path)
2778{
2779 struct btrfs_key key;
2780
2781 btrfs_node_key_to_cpu(node->eb, &key, 0);
2782 return do_relocation(trans, rc, node, &key, path, 0);
2783}
2784
2785static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2786 struct reloc_control *rc,
2787 struct btrfs_path *path, int err)
2788{
2789 LIST_HEAD(list);
2790 struct backref_cache *cache = &rc->backref_cache;
2791 struct backref_node *node;
2792 int level;
2793 int ret;
2794
2795 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2796 while (!list_empty(&cache->pending[level])) {
2797 node = list_entry(cache->pending[level].next,
2798 struct backref_node, list);
2799 list_move_tail(&node->list, &list);
2800 BUG_ON(!node->pending);
2801
2802 if (!err) {
2803 ret = link_to_upper(trans, rc, node, path);
2804 if (ret < 0)
2805 err = ret;
2806 }
2807 }
2808 list_splice_init(&list, &cache->pending[level]);
2809 }
2810 return err;
2811}
2812
2813static void mark_block_processed(struct reloc_control *rc,
2814 u64 bytenr, u32 blocksize)
2815{
2816 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2817 EXTENT_DIRTY, GFP_NOFS);
2818}
2819
2820static void __mark_block_processed(struct reloc_control *rc,
2821 struct backref_node *node)
2822{
2823 u32 blocksize;
2824 if (node->level == 0 ||
2825 in_block_group(node->bytenr, rc->block_group)) {
2826 blocksize = rc->extent_root->nodesize;
2827 mark_block_processed(rc, node->bytenr, blocksize);
2828 }
2829 node->processed = 1;
2830}
2831
2832/*
2833 * mark a block and all blocks directly/indirectly reference the block
2834 * as processed.
2835 */
2836static void update_processed_blocks(struct reloc_control *rc,
2837 struct backref_node *node)
2838{
2839 struct backref_node *next = node;
2840 struct backref_edge *edge;
2841 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2842 int index = 0;
2843
2844 while (next) {
2845 cond_resched();
2846 while (1) {
2847 if (next->processed)
2848 break;
2849
2850 __mark_block_processed(rc, next);
2851
2852 if (list_empty(&next->upper))
2853 break;
2854
2855 edge = list_entry(next->upper.next,
2856 struct backref_edge, list[LOWER]);
2857 edges[index++] = edge;
2858 next = edge->node[UPPER];
2859 }
2860 next = walk_down_backref(edges, &index);
2861 }
2862}
2863
2864static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2865{
2866 u32 blocksize = rc->extent_root->nodesize;
2867
2868 if (test_range_bit(&rc->processed_blocks, bytenr,
2869 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2870 return 1;
2871 return 0;
2872}
2873
2874static int get_tree_block_key(struct reloc_control *rc,
2875 struct tree_block *block)
2876{
2877 struct extent_buffer *eb;
2878
2879 BUG_ON(block->key_ready);
2880 eb = read_tree_block(rc->extent_root, block->bytenr,
2881 block->key.offset);
2882 if (IS_ERR(eb)) {
2883 return PTR_ERR(eb);
2884 } else if (!extent_buffer_uptodate(eb)) {
2885 free_extent_buffer(eb);
2886 return -EIO;
2887 }
2888 WARN_ON(btrfs_header_level(eb) != block->level);
2889 if (block->level == 0)
2890 btrfs_item_key_to_cpu(eb, &block->key, 0);
2891 else
2892 btrfs_node_key_to_cpu(eb, &block->key, 0);
2893 free_extent_buffer(eb);
2894 block->key_ready = 1;
2895 return 0;
2896}
2897
2898/*
2899 * helper function to relocate a tree block
2900 */
2901static int relocate_tree_block(struct btrfs_trans_handle *trans,
2902 struct reloc_control *rc,
2903 struct backref_node *node,
2904 struct btrfs_key *key,
2905 struct btrfs_path *path)
2906{
2907 struct btrfs_root *root;
2908 int ret = 0;
2909
2910 if (!node)
2911 return 0;
2912
2913 BUG_ON(node->processed);
2914 root = select_one_root(node);
2915 if (root == ERR_PTR(-ENOENT)) {
2916 update_processed_blocks(rc, node);
2917 goto out;
2918 }
2919
2920 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2921 ret = reserve_metadata_space(trans, rc, node);
2922 if (ret)
2923 goto out;
2924 }
2925
2926 if (root) {
2927 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2928 BUG_ON(node->new_bytenr);
2929 BUG_ON(!list_empty(&node->list));
2930 btrfs_record_root_in_trans(trans, root);
2931 root = root->reloc_root;
2932 node->new_bytenr = root->node->start;
2933 node->root = root;
2934 list_add_tail(&node->list, &rc->backref_cache.changed);
2935 } else {
2936 path->lowest_level = node->level;
2937 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2938 btrfs_release_path(path);
2939 if (ret > 0)
2940 ret = 0;
2941 }
2942 if (!ret)
2943 update_processed_blocks(rc, node);
2944 } else {
2945 ret = do_relocation(trans, rc, node, key, path, 1);
2946 }
2947out:
2948 if (ret || node->level == 0 || node->cowonly)
2949 remove_backref_node(&rc->backref_cache, node);
2950 return ret;
2951}
2952
2953/*
2954 * relocate a list of blocks
2955 */
2956static noinline_for_stack
2957int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2958 struct reloc_control *rc, struct rb_root *blocks)
2959{
2960 struct backref_node *node;
2961 struct btrfs_path *path;
2962 struct tree_block *block;
2963 struct rb_node *rb_node;
2964 int ret;
2965 int err = 0;
2966
2967 path = btrfs_alloc_path();
2968 if (!path) {
2969 err = -ENOMEM;
2970 goto out_free_blocks;
2971 }
2972
2973 rb_node = rb_first(blocks);
2974 while (rb_node) {
2975 block = rb_entry(rb_node, struct tree_block, rb_node);
2976 if (!block->key_ready)
2977 readahead_tree_block(rc->extent_root, block->bytenr);
2978 rb_node = rb_next(rb_node);
2979 }
2980
2981 rb_node = rb_first(blocks);
2982 while (rb_node) {
2983 block = rb_entry(rb_node, struct tree_block, rb_node);
2984 if (!block->key_ready) {
2985 err = get_tree_block_key(rc, block);
2986 if (err)
2987 goto out_free_path;
2988 }
2989 rb_node = rb_next(rb_node);
2990 }
2991
2992 rb_node = rb_first(blocks);
2993 while (rb_node) {
2994 block = rb_entry(rb_node, struct tree_block, rb_node);
2995
2996 node = build_backref_tree(rc, &block->key,
2997 block->level, block->bytenr);
2998 if (IS_ERR(node)) {
2999 err = PTR_ERR(node);
3000 goto out;
3001 }
3002
3003 ret = relocate_tree_block(trans, rc, node, &block->key,
3004 path);
3005 if (ret < 0) {
3006 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3007 err = ret;
3008 goto out;
3009 }
3010 rb_node = rb_next(rb_node);
3011 }
3012out:
3013 err = finish_pending_nodes(trans, rc, path, err);
3014
3015out_free_path:
3016 btrfs_free_path(path);
3017out_free_blocks:
3018 free_block_list(blocks);
3019 return err;
3020}
3021
3022static noinline_for_stack
3023int prealloc_file_extent_cluster(struct inode *inode,
3024 struct file_extent_cluster *cluster)
3025{
3026 u64 alloc_hint = 0;
3027 u64 start;
3028 u64 end;
3029 u64 offset = BTRFS_I(inode)->index_cnt;
3030 u64 num_bytes;
3031 int nr = 0;
3032 int ret = 0;
3033
3034 BUG_ON(cluster->start != cluster->boundary[0]);
3035 inode_lock(inode);
3036
3037 ret = btrfs_check_data_free_space(inode, cluster->start,
3038 cluster->end + 1 - cluster->start);
3039 if (ret)
3040 goto out;
3041
3042 while (nr < cluster->nr) {
3043 start = cluster->boundary[nr] - offset;
3044 if (nr + 1 < cluster->nr)
3045 end = cluster->boundary[nr + 1] - 1 - offset;
3046 else
3047 end = cluster->end - offset;
3048
3049 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3050 num_bytes = end + 1 - start;
3051 ret = btrfs_prealloc_file_range(inode, 0, start,
3052 num_bytes, num_bytes,
3053 end + 1, &alloc_hint);
3054 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3055 if (ret)
3056 break;
3057 nr++;
3058 }
3059 btrfs_free_reserved_data_space(inode, cluster->start,
3060 cluster->end + 1 - cluster->start);
3061out:
3062 inode_unlock(inode);
3063 return ret;
3064}
3065
3066static noinline_for_stack
3067int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3068 u64 block_start)
3069{
3070 struct btrfs_root *root = BTRFS_I(inode)->root;
3071 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3072 struct extent_map *em;
3073 int ret = 0;
3074
3075 em = alloc_extent_map();
3076 if (!em)
3077 return -ENOMEM;
3078
3079 em->start = start;
3080 em->len = end + 1 - start;
3081 em->block_len = em->len;
3082 em->block_start = block_start;
3083 em->bdev = root->fs_info->fs_devices->latest_bdev;
3084 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3085
3086 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3087 while (1) {
3088 write_lock(&em_tree->lock);
3089 ret = add_extent_mapping(em_tree, em, 0);
3090 write_unlock(&em_tree->lock);
3091 if (ret != -EEXIST) {
3092 free_extent_map(em);
3093 break;
3094 }
3095 btrfs_drop_extent_cache(inode, start, end, 0);
3096 }
3097 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3098 return ret;
3099}
3100
3101static int relocate_file_extent_cluster(struct inode *inode,
3102 struct file_extent_cluster *cluster)
3103{
3104 u64 page_start;
3105 u64 page_end;
3106 u64 offset = BTRFS_I(inode)->index_cnt;
3107 unsigned long index;
3108 unsigned long last_index;
3109 struct page *page;
3110 struct file_ra_state *ra;
3111 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3112 int nr = 0;
3113 int ret = 0;
3114
3115 if (!cluster->nr)
3116 return 0;
3117
3118 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3119 if (!ra)
3120 return -ENOMEM;
3121
3122 ret = prealloc_file_extent_cluster(inode, cluster);
3123 if (ret)
3124 goto out;
3125
3126 file_ra_state_init(ra, inode->i_mapping);
3127
3128 ret = setup_extent_mapping(inode, cluster->start - offset,
3129 cluster->end - offset, cluster->start);
3130 if (ret)
3131 goto out;
3132
3133 index = (cluster->start - offset) >> PAGE_SHIFT;
3134 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3135 while (index <= last_index) {
3136 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_SIZE);
3137 if (ret)
3138 goto out;
3139
3140 page = find_lock_page(inode->i_mapping, index);
3141 if (!page) {
3142 page_cache_sync_readahead(inode->i_mapping,
3143 ra, NULL, index,
3144 last_index + 1 - index);
3145 page = find_or_create_page(inode->i_mapping, index,
3146 mask);
3147 if (!page) {
3148 btrfs_delalloc_release_metadata(inode,
3149 PAGE_SIZE);
3150 ret = -ENOMEM;
3151 goto out;
3152 }
3153 }
3154
3155 if (PageReadahead(page)) {
3156 page_cache_async_readahead(inode->i_mapping,
3157 ra, NULL, page, index,
3158 last_index + 1 - index);
3159 }
3160
3161 if (!PageUptodate(page)) {
3162 btrfs_readpage(NULL, page);
3163 lock_page(page);
3164 if (!PageUptodate(page)) {
3165 unlock_page(page);
3166 put_page(page);
3167 btrfs_delalloc_release_metadata(inode,
3168 PAGE_SIZE);
3169 ret = -EIO;
3170 goto out;
3171 }
3172 }
3173
3174 page_start = page_offset(page);
3175 page_end = page_start + PAGE_SIZE - 1;
3176
3177 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3178
3179 set_page_extent_mapped(page);
3180
3181 if (nr < cluster->nr &&
3182 page_start + offset == cluster->boundary[nr]) {
3183 set_extent_bits(&BTRFS_I(inode)->io_tree,
3184 page_start, page_end,
3185 EXTENT_BOUNDARY, GFP_NOFS);
3186 nr++;
3187 }
3188
3189 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3190 set_page_dirty(page);
3191
3192 unlock_extent(&BTRFS_I(inode)->io_tree,
3193 page_start, page_end);
3194 unlock_page(page);
3195 put_page(page);
3196
3197 index++;
3198 balance_dirty_pages_ratelimited(inode->i_mapping);
3199 btrfs_throttle(BTRFS_I(inode)->root);
3200 }
3201 WARN_ON(nr != cluster->nr);
3202out:
3203 kfree(ra);
3204 return ret;
3205}
3206
3207static noinline_for_stack
3208int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3209 struct file_extent_cluster *cluster)
3210{
3211 int ret;
3212
3213 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3214 ret = relocate_file_extent_cluster(inode, cluster);
3215 if (ret)
3216 return ret;
3217 cluster->nr = 0;
3218 }
3219
3220 if (!cluster->nr)
3221 cluster->start = extent_key->objectid;
3222 else
3223 BUG_ON(cluster->nr >= MAX_EXTENTS);
3224 cluster->end = extent_key->objectid + extent_key->offset - 1;
3225 cluster->boundary[cluster->nr] = extent_key->objectid;
3226 cluster->nr++;
3227
3228 if (cluster->nr >= MAX_EXTENTS) {
3229 ret = relocate_file_extent_cluster(inode, cluster);
3230 if (ret)
3231 return ret;
3232 cluster->nr = 0;
3233 }
3234 return 0;
3235}
3236
3237#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3238static int get_ref_objectid_v0(struct reloc_control *rc,
3239 struct btrfs_path *path,
3240 struct btrfs_key *extent_key,
3241 u64 *ref_objectid, int *path_change)
3242{
3243 struct btrfs_key key;
3244 struct extent_buffer *leaf;
3245 struct btrfs_extent_ref_v0 *ref0;
3246 int ret;
3247 int slot;
3248
3249 leaf = path->nodes[0];
3250 slot = path->slots[0];
3251 while (1) {
3252 if (slot >= btrfs_header_nritems(leaf)) {
3253 ret = btrfs_next_leaf(rc->extent_root, path);
3254 if (ret < 0)
3255 return ret;
3256 BUG_ON(ret > 0);
3257 leaf = path->nodes[0];
3258 slot = path->slots[0];
3259 if (path_change)
3260 *path_change = 1;
3261 }
3262 btrfs_item_key_to_cpu(leaf, &key, slot);
3263 if (key.objectid != extent_key->objectid)
3264 return -ENOENT;
3265
3266 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3267 slot++;
3268 continue;
3269 }
3270 ref0 = btrfs_item_ptr(leaf, slot,
3271 struct btrfs_extent_ref_v0);
3272 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3273 break;
3274 }
3275 return 0;
3276}
3277#endif
3278
3279/*
3280 * helper to add a tree block to the list.
3281 * the major work is getting the generation and level of the block
3282 */
3283static int add_tree_block(struct reloc_control *rc,
3284 struct btrfs_key *extent_key,
3285 struct btrfs_path *path,
3286 struct rb_root *blocks)
3287{
3288 struct extent_buffer *eb;
3289 struct btrfs_extent_item *ei;
3290 struct btrfs_tree_block_info *bi;
3291 struct tree_block *block;
3292 struct rb_node *rb_node;
3293 u32 item_size;
3294 int level = -1;
3295 u64 generation;
3296
3297 eb = path->nodes[0];
3298 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3299
3300 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3301 item_size >= sizeof(*ei) + sizeof(*bi)) {
3302 ei = btrfs_item_ptr(eb, path->slots[0],
3303 struct btrfs_extent_item);
3304 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3305 bi = (struct btrfs_tree_block_info *)(ei + 1);
3306 level = btrfs_tree_block_level(eb, bi);
3307 } else {
3308 level = (int)extent_key->offset;
3309 }
3310 generation = btrfs_extent_generation(eb, ei);
3311 } else {
3312#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3313 u64 ref_owner;
3314 int ret;
3315
3316 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3317 ret = get_ref_objectid_v0(rc, path, extent_key,
3318 &ref_owner, NULL);
3319 if (ret < 0)
3320 return ret;
3321 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3322 level = (int)ref_owner;
3323 /* FIXME: get real generation */
3324 generation = 0;
3325#else
3326 BUG();
3327#endif
3328 }
3329
3330 btrfs_release_path(path);
3331
3332 BUG_ON(level == -1);
3333
3334 block = kmalloc(sizeof(*block), GFP_NOFS);
3335 if (!block)
3336 return -ENOMEM;
3337
3338 block->bytenr = extent_key->objectid;
3339 block->key.objectid = rc->extent_root->nodesize;
3340 block->key.offset = generation;
3341 block->level = level;
3342 block->key_ready = 0;
3343
3344 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3345 if (rb_node)
3346 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3347
3348 return 0;
3349}
3350
3351/*
3352 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3353 */
3354static int __add_tree_block(struct reloc_control *rc,
3355 u64 bytenr, u32 blocksize,
3356 struct rb_root *blocks)
3357{
3358 struct btrfs_path *path;
3359 struct btrfs_key key;
3360 int ret;
3361 bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info,
3362 SKINNY_METADATA);
3363
3364 if (tree_block_processed(bytenr, rc))
3365 return 0;
3366
3367 if (tree_search(blocks, bytenr))
3368 return 0;
3369
3370 path = btrfs_alloc_path();
3371 if (!path)
3372 return -ENOMEM;
3373again:
3374 key.objectid = bytenr;
3375 if (skinny) {
3376 key.type = BTRFS_METADATA_ITEM_KEY;
3377 key.offset = (u64)-1;
3378 } else {
3379 key.type = BTRFS_EXTENT_ITEM_KEY;
3380 key.offset = blocksize;
3381 }
3382
3383 path->search_commit_root = 1;
3384 path->skip_locking = 1;
3385 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3386 if (ret < 0)
3387 goto out;
3388
3389 if (ret > 0 && skinny) {
3390 if (path->slots[0]) {
3391 path->slots[0]--;
3392 btrfs_item_key_to_cpu(path->nodes[0], &key,
3393 path->slots[0]);
3394 if (key.objectid == bytenr &&
3395 (key.type == BTRFS_METADATA_ITEM_KEY ||
3396 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3397 key.offset == blocksize)))
3398 ret = 0;
3399 }
3400
3401 if (ret) {
3402 skinny = false;
3403 btrfs_release_path(path);
3404 goto again;
3405 }
3406 }
3407 BUG_ON(ret);
3408
3409 ret = add_tree_block(rc, &key, path, blocks);
3410out:
3411 btrfs_free_path(path);
3412 return ret;
3413}
3414
3415/*
3416 * helper to check if the block use full backrefs for pointers in it
3417 */
3418static int block_use_full_backref(struct reloc_control *rc,
3419 struct extent_buffer *eb)
3420{
3421 u64 flags;
3422 int ret;
3423
3424 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3425 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3426 return 1;
3427
3428 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3429 eb->start, btrfs_header_level(eb), 1,
3430 NULL, &flags);
3431 BUG_ON(ret);
3432
3433 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3434 ret = 1;
3435 else
3436 ret = 0;
3437 return ret;
3438}
3439
3440static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3441 struct btrfs_block_group_cache *block_group,
3442 struct inode *inode,
3443 u64 ino)
3444{
3445 struct btrfs_key key;
3446 struct btrfs_root *root = fs_info->tree_root;
3447 struct btrfs_trans_handle *trans;
3448 int ret = 0;
3449
3450 if (inode)
3451 goto truncate;
3452
3453 key.objectid = ino;
3454 key.type = BTRFS_INODE_ITEM_KEY;
3455 key.offset = 0;
3456
3457 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3458 if (IS_ERR(inode) || is_bad_inode(inode)) {
3459 if (!IS_ERR(inode))
3460 iput(inode);
3461 return -ENOENT;
3462 }
3463
3464truncate:
3465 ret = btrfs_check_trunc_cache_free_space(root,
3466 &fs_info->global_block_rsv);
3467 if (ret)
3468 goto out;
3469
3470 trans = btrfs_join_transaction(root);
3471 if (IS_ERR(trans)) {
3472 ret = PTR_ERR(trans);
3473 goto out;
3474 }
3475
3476 ret = btrfs_truncate_free_space_cache(root, trans, block_group, inode);
3477
3478 btrfs_end_transaction(trans, root);
3479 btrfs_btree_balance_dirty(root);
3480out:
3481 iput(inode);
3482 return ret;
3483}
3484
3485/*
3486 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3487 * this function scans fs tree to find blocks reference the data extent
3488 */
3489static int find_data_references(struct reloc_control *rc,
3490 struct btrfs_key *extent_key,
3491 struct extent_buffer *leaf,
3492 struct btrfs_extent_data_ref *ref,
3493 struct rb_root *blocks)
3494{
3495 struct btrfs_path *path;
3496 struct tree_block *block;
3497 struct btrfs_root *root;
3498 struct btrfs_file_extent_item *fi;
3499 struct rb_node *rb_node;
3500 struct btrfs_key key;
3501 u64 ref_root;
3502 u64 ref_objectid;
3503 u64 ref_offset;
3504 u32 ref_count;
3505 u32 nritems;
3506 int err = 0;
3507 int added = 0;
3508 int counted;
3509 int ret;
3510
3511 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3512 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3513 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3514 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3515
3516 /*
3517 * This is an extent belonging to the free space cache, lets just delete
3518 * it and redo the search.
3519 */
3520 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3521 ret = delete_block_group_cache(rc->extent_root->fs_info,
3522 rc->block_group,
3523 NULL, ref_objectid);
3524 if (ret != -ENOENT)
3525 return ret;
3526 ret = 0;
3527 }
3528
3529 path = btrfs_alloc_path();
3530 if (!path)
3531 return -ENOMEM;
3532 path->reada = READA_FORWARD;
3533
3534 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3535 if (IS_ERR(root)) {
3536 err = PTR_ERR(root);
3537 goto out;
3538 }
3539
3540 key.objectid = ref_objectid;
3541 key.type = BTRFS_EXTENT_DATA_KEY;
3542 if (ref_offset > ((u64)-1 << 32))
3543 key.offset = 0;
3544 else
3545 key.offset = ref_offset;
3546
3547 path->search_commit_root = 1;
3548 path->skip_locking = 1;
3549 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3550 if (ret < 0) {
3551 err = ret;
3552 goto out;
3553 }
3554
3555 leaf = path->nodes[0];
3556 nritems = btrfs_header_nritems(leaf);
3557 /*
3558 * the references in tree blocks that use full backrefs
3559 * are not counted in
3560 */
3561 if (block_use_full_backref(rc, leaf))
3562 counted = 0;
3563 else
3564 counted = 1;
3565 rb_node = tree_search(blocks, leaf->start);
3566 if (rb_node) {
3567 if (counted)
3568 added = 1;
3569 else
3570 path->slots[0] = nritems;
3571 }
3572
3573 while (ref_count > 0) {
3574 while (path->slots[0] >= nritems) {
3575 ret = btrfs_next_leaf(root, path);
3576 if (ret < 0) {
3577 err = ret;
3578 goto out;
3579 }
3580 if (WARN_ON(ret > 0))
3581 goto out;
3582
3583 leaf = path->nodes[0];
3584 nritems = btrfs_header_nritems(leaf);
3585 added = 0;
3586
3587 if (block_use_full_backref(rc, leaf))
3588 counted = 0;
3589 else
3590 counted = 1;
3591 rb_node = tree_search(blocks, leaf->start);
3592 if (rb_node) {
3593 if (counted)
3594 added = 1;
3595 else
3596 path->slots[0] = nritems;
3597 }
3598 }
3599
3600 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3601 if (WARN_ON(key.objectid != ref_objectid ||
3602 key.type != BTRFS_EXTENT_DATA_KEY))
3603 break;
3604
3605 fi = btrfs_item_ptr(leaf, path->slots[0],
3606 struct btrfs_file_extent_item);
3607
3608 if (btrfs_file_extent_type(leaf, fi) ==
3609 BTRFS_FILE_EXTENT_INLINE)
3610 goto next;
3611
3612 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3613 extent_key->objectid)
3614 goto next;
3615
3616 key.offset -= btrfs_file_extent_offset(leaf, fi);
3617 if (key.offset != ref_offset)
3618 goto next;
3619
3620 if (counted)
3621 ref_count--;
3622 if (added)
3623 goto next;
3624
3625 if (!tree_block_processed(leaf->start, rc)) {
3626 block = kmalloc(sizeof(*block), GFP_NOFS);
3627 if (!block) {
3628 err = -ENOMEM;
3629 break;
3630 }
3631 block->bytenr = leaf->start;
3632 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3633 block->level = 0;
3634 block->key_ready = 1;
3635 rb_node = tree_insert(blocks, block->bytenr,
3636 &block->rb_node);
3637 if (rb_node)
3638 backref_tree_panic(rb_node, -EEXIST,
3639 block->bytenr);
3640 }
3641 if (counted)
3642 added = 1;
3643 else
3644 path->slots[0] = nritems;
3645next:
3646 path->slots[0]++;
3647
3648 }
3649out:
3650 btrfs_free_path(path);
3651 return err;
3652}
3653
3654/*
3655 * helper to find all tree blocks that reference a given data extent
3656 */
3657static noinline_for_stack
3658int add_data_references(struct reloc_control *rc,
3659 struct btrfs_key *extent_key,
3660 struct btrfs_path *path,
3661 struct rb_root *blocks)
3662{
3663 struct btrfs_key key;
3664 struct extent_buffer *eb;
3665 struct btrfs_extent_data_ref *dref;
3666 struct btrfs_extent_inline_ref *iref;
3667 unsigned long ptr;
3668 unsigned long end;
3669 u32 blocksize = rc->extent_root->nodesize;
3670 int ret = 0;
3671 int err = 0;
3672
3673 eb = path->nodes[0];
3674 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3675 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3676#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3677 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3678 ptr = end;
3679 else
3680#endif
3681 ptr += sizeof(struct btrfs_extent_item);
3682
3683 while (ptr < end) {
3684 iref = (struct btrfs_extent_inline_ref *)ptr;
3685 key.type = btrfs_extent_inline_ref_type(eb, iref);
3686 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3687 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3688 ret = __add_tree_block(rc, key.offset, blocksize,
3689 blocks);
3690 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3691 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3692 ret = find_data_references(rc, extent_key,
3693 eb, dref, blocks);
3694 } else {
3695 BUG();
3696 }
3697 if (ret) {
3698 err = ret;
3699 goto out;
3700 }
3701 ptr += btrfs_extent_inline_ref_size(key.type);
3702 }
3703 WARN_ON(ptr > end);
3704
3705 while (1) {
3706 cond_resched();
3707 eb = path->nodes[0];
3708 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3709 ret = btrfs_next_leaf(rc->extent_root, path);
3710 if (ret < 0) {
3711 err = ret;
3712 break;
3713 }
3714 if (ret > 0)
3715 break;
3716 eb = path->nodes[0];
3717 }
3718
3719 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3720 if (key.objectid != extent_key->objectid)
3721 break;
3722
3723#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3724 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3725 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3726#else
3727 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3728 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3729#endif
3730 ret = __add_tree_block(rc, key.offset, blocksize,
3731 blocks);
3732 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3733 dref = btrfs_item_ptr(eb, path->slots[0],
3734 struct btrfs_extent_data_ref);
3735 ret = find_data_references(rc, extent_key,
3736 eb, dref, blocks);
3737 } else {
3738 ret = 0;
3739 }
3740 if (ret) {
3741 err = ret;
3742 break;
3743 }
3744 path->slots[0]++;
3745 }
3746out:
3747 btrfs_release_path(path);
3748 if (err)
3749 free_block_list(blocks);
3750 return err;
3751}
3752
3753/*
3754 * helper to find next unprocessed extent
3755 */
3756static noinline_for_stack
3757int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3758 struct btrfs_key *extent_key)
3759{
3760 struct btrfs_key key;
3761 struct extent_buffer *leaf;
3762 u64 start, end, last;
3763 int ret;
3764
3765 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3766 while (1) {
3767 cond_resched();
3768 if (rc->search_start >= last) {
3769 ret = 1;
3770 break;
3771 }
3772
3773 key.objectid = rc->search_start;
3774 key.type = BTRFS_EXTENT_ITEM_KEY;
3775 key.offset = 0;
3776
3777 path->search_commit_root = 1;
3778 path->skip_locking = 1;
3779 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3780 0, 0);
3781 if (ret < 0)
3782 break;
3783next:
3784 leaf = path->nodes[0];
3785 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3786 ret = btrfs_next_leaf(rc->extent_root, path);
3787 if (ret != 0)
3788 break;
3789 leaf = path->nodes[0];
3790 }
3791
3792 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3793 if (key.objectid >= last) {
3794 ret = 1;
3795 break;
3796 }
3797
3798 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3799 key.type != BTRFS_METADATA_ITEM_KEY) {
3800 path->slots[0]++;
3801 goto next;
3802 }
3803
3804 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3805 key.objectid + key.offset <= rc->search_start) {
3806 path->slots[0]++;
3807 goto next;
3808 }
3809
3810 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3811 key.objectid + rc->extent_root->nodesize <=
3812 rc->search_start) {
3813 path->slots[0]++;
3814 goto next;
3815 }
3816
3817 ret = find_first_extent_bit(&rc->processed_blocks,
3818 key.objectid, &start, &end,
3819 EXTENT_DIRTY, NULL);
3820
3821 if (ret == 0 && start <= key.objectid) {
3822 btrfs_release_path(path);
3823 rc->search_start = end + 1;
3824 } else {
3825 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3826 rc->search_start = key.objectid + key.offset;
3827 else
3828 rc->search_start = key.objectid +
3829 rc->extent_root->nodesize;
3830 memcpy(extent_key, &key, sizeof(key));
3831 return 0;
3832 }
3833 }
3834 btrfs_release_path(path);
3835 return ret;
3836}
3837
3838static void set_reloc_control(struct reloc_control *rc)
3839{
3840 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3841
3842 mutex_lock(&fs_info->reloc_mutex);
3843 fs_info->reloc_ctl = rc;
3844 mutex_unlock(&fs_info->reloc_mutex);
3845}
3846
3847static void unset_reloc_control(struct reloc_control *rc)
3848{
3849 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3850
3851 mutex_lock(&fs_info->reloc_mutex);
3852 fs_info->reloc_ctl = NULL;
3853 mutex_unlock(&fs_info->reloc_mutex);
3854}
3855
3856static int check_extent_flags(u64 flags)
3857{
3858 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3859 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3860 return 1;
3861 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3862 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3863 return 1;
3864 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3865 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3866 return 1;
3867 return 0;
3868}
3869
3870static noinline_for_stack
3871int prepare_to_relocate(struct reloc_control *rc)
3872{
3873 struct btrfs_trans_handle *trans;
3874
3875 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3876 BTRFS_BLOCK_RSV_TEMP);
3877 if (!rc->block_rsv)
3878 return -ENOMEM;
3879
3880 memset(&rc->cluster, 0, sizeof(rc->cluster));
3881 rc->search_start = rc->block_group->key.objectid;
3882 rc->extents_found = 0;
3883 rc->nodes_relocated = 0;
3884 rc->merging_rsv_size = 0;
3885 rc->reserved_bytes = 0;
3886 rc->block_rsv->size = rc->extent_root->nodesize *
3887 RELOCATION_RESERVED_NODES;
3888
3889 rc->create_reloc_tree = 1;
3890 set_reloc_control(rc);
3891
3892 trans = btrfs_join_transaction(rc->extent_root);
3893 if (IS_ERR(trans)) {
3894 unset_reloc_control(rc);
3895 /*
3896 * extent tree is not a ref_cow tree and has no reloc_root to
3897 * cleanup. And callers are responsible to free the above
3898 * block rsv.
3899 */
3900 return PTR_ERR(trans);
3901 }
3902 btrfs_commit_transaction(trans, rc->extent_root);
3903 return 0;
3904}
3905
3906static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3907{
3908 struct rb_root blocks = RB_ROOT;
3909 struct btrfs_key key;
3910 struct btrfs_trans_handle *trans = NULL;
3911 struct btrfs_path *path;
3912 struct btrfs_extent_item *ei;
3913 u64 flags;
3914 u32 item_size;
3915 int ret;
3916 int err = 0;
3917 int progress = 0;
3918
3919 path = btrfs_alloc_path();
3920 if (!path)
3921 return -ENOMEM;
3922 path->reada = READA_FORWARD;
3923
3924 ret = prepare_to_relocate(rc);
3925 if (ret) {
3926 err = ret;
3927 goto out_free;
3928 }
3929
3930 while (1) {
3931 rc->reserved_bytes = 0;
3932 ret = btrfs_block_rsv_refill(rc->extent_root,
3933 rc->block_rsv, rc->block_rsv->size,
3934 BTRFS_RESERVE_FLUSH_ALL);
3935 if (ret) {
3936 err = ret;
3937 break;
3938 }
3939 progress++;
3940 trans = btrfs_start_transaction(rc->extent_root, 0);
3941 if (IS_ERR(trans)) {
3942 err = PTR_ERR(trans);
3943 trans = NULL;
3944 break;
3945 }
3946restart:
3947 if (update_backref_cache(trans, &rc->backref_cache)) {
3948 btrfs_end_transaction(trans, rc->extent_root);
3949 continue;
3950 }
3951
3952 ret = find_next_extent(rc, path, &key);
3953 if (ret < 0)
3954 err = ret;
3955 if (ret != 0)
3956 break;
3957
3958 rc->extents_found++;
3959
3960 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3961 struct btrfs_extent_item);
3962 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3963 if (item_size >= sizeof(*ei)) {
3964 flags = btrfs_extent_flags(path->nodes[0], ei);
3965 ret = check_extent_flags(flags);
3966 BUG_ON(ret);
3967
3968 } else {
3969#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3970 u64 ref_owner;
3971 int path_change = 0;
3972
3973 BUG_ON(item_size !=
3974 sizeof(struct btrfs_extent_item_v0));
3975 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3976 &path_change);
3977 if (ret < 0) {
3978 err = ret;
3979 break;
3980 }
3981 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3982 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3983 else
3984 flags = BTRFS_EXTENT_FLAG_DATA;
3985
3986 if (path_change) {
3987 btrfs_release_path(path);
3988
3989 path->search_commit_root = 1;
3990 path->skip_locking = 1;
3991 ret = btrfs_search_slot(NULL, rc->extent_root,
3992 &key, path, 0, 0);
3993 if (ret < 0) {
3994 err = ret;
3995 break;
3996 }
3997 BUG_ON(ret > 0);
3998 }
3999#else
4000 BUG();
4001#endif
4002 }
4003
4004 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4005 ret = add_tree_block(rc, &key, path, &blocks);
4006 } else if (rc->stage == UPDATE_DATA_PTRS &&
4007 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4008 ret = add_data_references(rc, &key, path, &blocks);
4009 } else {
4010 btrfs_release_path(path);
4011 ret = 0;
4012 }
4013 if (ret < 0) {
4014 err = ret;
4015 break;
4016 }
4017
4018 if (!RB_EMPTY_ROOT(&blocks)) {
4019 ret = relocate_tree_blocks(trans, rc, &blocks);
4020 if (ret < 0) {
4021 /*
4022 * if we fail to relocate tree blocks, force to update
4023 * backref cache when committing transaction.
4024 */
4025 rc->backref_cache.last_trans = trans->transid - 1;
4026
4027 if (ret != -EAGAIN) {
4028 err = ret;
4029 break;
4030 }
4031 rc->extents_found--;
4032 rc->search_start = key.objectid;
4033 }
4034 }
4035
4036 btrfs_end_transaction_throttle(trans, rc->extent_root);
4037 btrfs_btree_balance_dirty(rc->extent_root);
4038 trans = NULL;
4039
4040 if (rc->stage == MOVE_DATA_EXTENTS &&
4041 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4042 rc->found_file_extent = 1;
4043 ret = relocate_data_extent(rc->data_inode,
4044 &key, &rc->cluster);
4045 if (ret < 0) {
4046 err = ret;
4047 break;
4048 }
4049 }
4050 }
4051 if (trans && progress && err == -ENOSPC) {
4052 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
4053 rc->block_group->flags);
4054 if (ret == 1) {
4055 err = 0;
4056 progress = 0;
4057 goto restart;
4058 }
4059 }
4060
4061 btrfs_release_path(path);
4062 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
4063 GFP_NOFS);
4064
4065 if (trans) {
4066 btrfs_end_transaction_throttle(trans, rc->extent_root);
4067 btrfs_btree_balance_dirty(rc->extent_root);
4068 }
4069
4070 if (!err) {
4071 ret = relocate_file_extent_cluster(rc->data_inode,
4072 &rc->cluster);
4073 if (ret < 0)
4074 err = ret;
4075 }
4076
4077 rc->create_reloc_tree = 0;
4078 set_reloc_control(rc);
4079
4080 backref_cache_cleanup(&rc->backref_cache);
4081 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4082
4083 err = prepare_to_merge(rc, err);
4084
4085 merge_reloc_roots(rc);
4086
4087 rc->merge_reloc_tree = 0;
4088 unset_reloc_control(rc);
4089 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4090
4091 /* get rid of pinned extents */
4092 trans = btrfs_join_transaction(rc->extent_root);
4093 if (IS_ERR(trans))
4094 err = PTR_ERR(trans);
4095 else
4096 btrfs_commit_transaction(trans, rc->extent_root);
4097out_free:
4098 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
4099 btrfs_free_path(path);
4100 return err;
4101}
4102
4103static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4104 struct btrfs_root *root, u64 objectid)
4105{
4106 struct btrfs_path *path;
4107 struct btrfs_inode_item *item;
4108 struct extent_buffer *leaf;
4109 int ret;
4110
4111 path = btrfs_alloc_path();
4112 if (!path)
4113 return -ENOMEM;
4114
4115 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4116 if (ret)
4117 goto out;
4118
4119 leaf = path->nodes[0];
4120 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4121 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4122 btrfs_set_inode_generation(leaf, item, 1);
4123 btrfs_set_inode_size(leaf, item, 0);
4124 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4125 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4126 BTRFS_INODE_PREALLOC);
4127 btrfs_mark_buffer_dirty(leaf);
4128out:
4129 btrfs_free_path(path);
4130 return ret;
4131}
4132
4133/*
4134 * helper to create inode for data relocation.
4135 * the inode is in data relocation tree and its link count is 0
4136 */
4137static noinline_for_stack
4138struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4139 struct btrfs_block_group_cache *group)
4140{
4141 struct inode *inode = NULL;
4142 struct btrfs_trans_handle *trans;
4143 struct btrfs_root *root;
4144 struct btrfs_key key;
4145 u64 objectid;
4146 int err = 0;
4147
4148 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4149 if (IS_ERR(root))
4150 return ERR_CAST(root);
4151
4152 trans = btrfs_start_transaction(root, 6);
4153 if (IS_ERR(trans))
4154 return ERR_CAST(trans);
4155
4156 err = btrfs_find_free_objectid(root, &objectid);
4157 if (err)
4158 goto out;
4159
4160 err = __insert_orphan_inode(trans, root, objectid);
4161 BUG_ON(err);
4162
4163 key.objectid = objectid;
4164 key.type = BTRFS_INODE_ITEM_KEY;
4165 key.offset = 0;
4166 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
4167 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4168 BTRFS_I(inode)->index_cnt = group->key.objectid;
4169
4170 err = btrfs_orphan_add(trans, inode);
4171out:
4172 btrfs_end_transaction(trans, root);
4173 btrfs_btree_balance_dirty(root);
4174 if (err) {
4175 if (inode)
4176 iput(inode);
4177 inode = ERR_PTR(err);
4178 }
4179 return inode;
4180}
4181
4182static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4183{
4184 struct reloc_control *rc;
4185
4186 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4187 if (!rc)
4188 return NULL;
4189
4190 INIT_LIST_HEAD(&rc->reloc_roots);
4191 backref_cache_init(&rc->backref_cache);
4192 mapping_tree_init(&rc->reloc_root_tree);
4193 extent_io_tree_init(&rc->processed_blocks,
4194 fs_info->btree_inode->i_mapping);
4195 return rc;
4196}
4197
4198/*
4199 * function to relocate all extents in a block group.
4200 */
4201int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4202{
4203 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4204 struct reloc_control *rc;
4205 struct inode *inode;
4206 struct btrfs_path *path;
4207 int ret;
4208 int rw = 0;
4209 int err = 0;
4210
4211 rc = alloc_reloc_control(fs_info);
4212 if (!rc)
4213 return -ENOMEM;
4214
4215 rc->extent_root = extent_root;
4216
4217 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4218 BUG_ON(!rc->block_group);
4219
4220 ret = btrfs_inc_block_group_ro(extent_root, rc->block_group);
4221 if (ret) {
4222 err = ret;
4223 goto out;
4224 }
4225 rw = 1;
4226
4227 path = btrfs_alloc_path();
4228 if (!path) {
4229 err = -ENOMEM;
4230 goto out;
4231 }
4232
4233 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4234 path);
4235 btrfs_free_path(path);
4236
4237 if (!IS_ERR(inode))
4238 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4239 else
4240 ret = PTR_ERR(inode);
4241
4242 if (ret && ret != -ENOENT) {
4243 err = ret;
4244 goto out;
4245 }
4246
4247 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4248 if (IS_ERR(rc->data_inode)) {
4249 err = PTR_ERR(rc->data_inode);
4250 rc->data_inode = NULL;
4251 goto out;
4252 }
4253
4254 btrfs_info(extent_root->fs_info, "relocating block group %llu flags %llu",
4255 rc->block_group->key.objectid, rc->block_group->flags);
4256
4257 ret = btrfs_start_delalloc_roots(fs_info, 0, -1);
4258 if (ret < 0) {
4259 err = ret;
4260 goto out;
4261 }
4262 btrfs_wait_ordered_roots(fs_info, -1);
4263
4264 while (1) {
4265 mutex_lock(&fs_info->cleaner_mutex);
4266 ret = relocate_block_group(rc);
4267 mutex_unlock(&fs_info->cleaner_mutex);
4268 if (ret < 0) {
4269 err = ret;
4270 goto out;
4271 }
4272
4273 if (rc->extents_found == 0)
4274 break;
4275
4276 btrfs_info(extent_root->fs_info, "found %llu extents",
4277 rc->extents_found);
4278
4279 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4280 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4281 (u64)-1);
4282 if (ret) {
4283 err = ret;
4284 goto out;
4285 }
4286 invalidate_mapping_pages(rc->data_inode->i_mapping,
4287 0, -1);
4288 rc->stage = UPDATE_DATA_PTRS;
4289 }
4290 }
4291
4292 WARN_ON(rc->block_group->pinned > 0);
4293 WARN_ON(rc->block_group->reserved > 0);
4294 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4295out:
4296 if (err && rw)
4297 btrfs_dec_block_group_ro(extent_root, rc->block_group);
4298 iput(rc->data_inode);
4299 btrfs_put_block_group(rc->block_group);
4300 kfree(rc);
4301 return err;
4302}
4303
4304static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4305{
4306 struct btrfs_trans_handle *trans;
4307 int ret, err;
4308
4309 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4310 if (IS_ERR(trans))
4311 return PTR_ERR(trans);
4312
4313 memset(&root->root_item.drop_progress, 0,
4314 sizeof(root->root_item.drop_progress));
4315 root->root_item.drop_level = 0;
4316 btrfs_set_root_refs(&root->root_item, 0);
4317 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4318 &root->root_key, &root->root_item);
4319
4320 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4321 if (err)
4322 return err;
4323 return ret;
4324}
4325
4326/*
4327 * recover relocation interrupted by system crash.
4328 *
4329 * this function resumes merging reloc trees with corresponding fs trees.
4330 * this is important for keeping the sharing of tree blocks
4331 */
4332int btrfs_recover_relocation(struct btrfs_root *root)
4333{
4334 LIST_HEAD(reloc_roots);
4335 struct btrfs_key key;
4336 struct btrfs_root *fs_root;
4337 struct btrfs_root *reloc_root;
4338 struct btrfs_path *path;
4339 struct extent_buffer *leaf;
4340 struct reloc_control *rc = NULL;
4341 struct btrfs_trans_handle *trans;
4342 int ret;
4343 int err = 0;
4344
4345 path = btrfs_alloc_path();
4346 if (!path)
4347 return -ENOMEM;
4348 path->reada = READA_BACK;
4349
4350 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4351 key.type = BTRFS_ROOT_ITEM_KEY;
4352 key.offset = (u64)-1;
4353
4354 while (1) {
4355 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4356 path, 0, 0);
4357 if (ret < 0) {
4358 err = ret;
4359 goto out;
4360 }
4361 if (ret > 0) {
4362 if (path->slots[0] == 0)
4363 break;
4364 path->slots[0]--;
4365 }
4366 leaf = path->nodes[0];
4367 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4368 btrfs_release_path(path);
4369
4370 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4371 key.type != BTRFS_ROOT_ITEM_KEY)
4372 break;
4373
4374 reloc_root = btrfs_read_fs_root(root, &key);
4375 if (IS_ERR(reloc_root)) {
4376 err = PTR_ERR(reloc_root);
4377 goto out;
4378 }
4379
4380 list_add(&reloc_root->root_list, &reloc_roots);
4381
4382 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4383 fs_root = read_fs_root(root->fs_info,
4384 reloc_root->root_key.offset);
4385 if (IS_ERR(fs_root)) {
4386 ret = PTR_ERR(fs_root);
4387 if (ret != -ENOENT) {
4388 err = ret;
4389 goto out;
4390 }
4391 ret = mark_garbage_root(reloc_root);
4392 if (ret < 0) {
4393 err = ret;
4394 goto out;
4395 }
4396 }
4397 }
4398
4399 if (key.offset == 0)
4400 break;
4401
4402 key.offset--;
4403 }
4404 btrfs_release_path(path);
4405
4406 if (list_empty(&reloc_roots))
4407 goto out;
4408
4409 rc = alloc_reloc_control(root->fs_info);
4410 if (!rc) {
4411 err = -ENOMEM;
4412 goto out;
4413 }
4414
4415 rc->extent_root = root->fs_info->extent_root;
4416
4417 set_reloc_control(rc);
4418
4419 trans = btrfs_join_transaction(rc->extent_root);
4420 if (IS_ERR(trans)) {
4421 unset_reloc_control(rc);
4422 err = PTR_ERR(trans);
4423 goto out_free;
4424 }
4425
4426 rc->merge_reloc_tree = 1;
4427
4428 while (!list_empty(&reloc_roots)) {
4429 reloc_root = list_entry(reloc_roots.next,
4430 struct btrfs_root, root_list);
4431 list_del(&reloc_root->root_list);
4432
4433 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4434 list_add_tail(&reloc_root->root_list,
4435 &rc->reloc_roots);
4436 continue;
4437 }
4438
4439 fs_root = read_fs_root(root->fs_info,
4440 reloc_root->root_key.offset);
4441 if (IS_ERR(fs_root)) {
4442 err = PTR_ERR(fs_root);
4443 goto out_free;
4444 }
4445
4446 err = __add_reloc_root(reloc_root);
4447 BUG_ON(err < 0); /* -ENOMEM or logic error */
4448 fs_root->reloc_root = reloc_root;
4449 }
4450
4451 err = btrfs_commit_transaction(trans, rc->extent_root);
4452 if (err)
4453 goto out_free;
4454
4455 merge_reloc_roots(rc);
4456
4457 unset_reloc_control(rc);
4458
4459 trans = btrfs_join_transaction(rc->extent_root);
4460 if (IS_ERR(trans))
4461 err = PTR_ERR(trans);
4462 else
4463 err = btrfs_commit_transaction(trans, rc->extent_root);
4464out_free:
4465 kfree(rc);
4466out:
4467 if (!list_empty(&reloc_roots))
4468 free_reloc_roots(&reloc_roots);
4469
4470 btrfs_free_path(path);
4471
4472 if (err == 0) {
4473 /* cleanup orphan inode in data relocation tree */
4474 fs_root = read_fs_root(root->fs_info,
4475 BTRFS_DATA_RELOC_TREE_OBJECTID);
4476 if (IS_ERR(fs_root))
4477 err = PTR_ERR(fs_root);
4478 else
4479 err = btrfs_orphan_cleanup(fs_root);
4480 }
4481 return err;
4482}
4483
4484/*
4485 * helper to add ordered checksum for data relocation.
4486 *
4487 * cloning checksum properly handles the nodatasum extents.
4488 * it also saves CPU time to re-calculate the checksum.
4489 */
4490int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4491{
4492 struct btrfs_ordered_sum *sums;
4493 struct btrfs_ordered_extent *ordered;
4494 struct btrfs_root *root = BTRFS_I(inode)->root;
4495 int ret;
4496 u64 disk_bytenr;
4497 u64 new_bytenr;
4498 LIST_HEAD(list);
4499
4500 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4501 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4502
4503 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4504 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4505 disk_bytenr + len - 1, &list, 0);
4506 if (ret)
4507 goto out;
4508
4509 while (!list_empty(&list)) {
4510 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4511 list_del_init(&sums->list);
4512
4513 /*
4514 * We need to offset the new_bytenr based on where the csum is.
4515 * We need to do this because we will read in entire prealloc
4516 * extents but we may have written to say the middle of the
4517 * prealloc extent, so we need to make sure the csum goes with
4518 * the right disk offset.
4519 *
4520 * We can do this because the data reloc inode refers strictly
4521 * to the on disk bytes, so we don't have to worry about
4522 * disk_len vs real len like with real inodes since it's all
4523 * disk length.
4524 */
4525 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4526 sums->bytenr = new_bytenr;
4527
4528 btrfs_add_ordered_sum(inode, ordered, sums);
4529 }
4530out:
4531 btrfs_put_ordered_extent(ordered);
4532 return ret;
4533}
4534
4535int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4536 struct btrfs_root *root, struct extent_buffer *buf,
4537 struct extent_buffer *cow)
4538{
4539 struct reloc_control *rc;
4540 struct backref_node *node;
4541 int first_cow = 0;
4542 int level;
4543 int ret = 0;
4544
4545 rc = root->fs_info->reloc_ctl;
4546 if (!rc)
4547 return 0;
4548
4549 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4550 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4551
4552 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4553 if (buf == root->node)
4554 __update_reloc_root(root, cow->start);
4555 }
4556
4557 level = btrfs_header_level(buf);
4558 if (btrfs_header_generation(buf) <=
4559 btrfs_root_last_snapshot(&root->root_item))
4560 first_cow = 1;
4561
4562 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4563 rc->create_reloc_tree) {
4564 WARN_ON(!first_cow && level == 0);
4565
4566 node = rc->backref_cache.path[level];
4567 BUG_ON(node->bytenr != buf->start &&
4568 node->new_bytenr != buf->start);
4569
4570 drop_node_buffer(node);
4571 extent_buffer_get(cow);
4572 node->eb = cow;
4573 node->new_bytenr = cow->start;
4574
4575 if (!node->pending) {
4576 list_move_tail(&node->list,
4577 &rc->backref_cache.pending[level]);
4578 node->pending = 1;
4579 }
4580
4581 if (first_cow)
4582 __mark_block_processed(rc, node);
4583
4584 if (first_cow && level > 0)
4585 rc->nodes_relocated += buf->len;
4586 }
4587
4588 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4589 ret = replace_file_extents(trans, rc, root, cow);
4590 return ret;
4591}
4592
4593/*
4594 * called before creating snapshot. it calculates metadata reservation
4595 * requried for relocating tree blocks in the snapshot
4596 */
4597void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4598 u64 *bytes_to_reserve)
4599{
4600 struct btrfs_root *root;
4601 struct reloc_control *rc;
4602
4603 root = pending->root;
4604 if (!root->reloc_root)
4605 return;
4606
4607 rc = root->fs_info->reloc_ctl;
4608 if (!rc->merge_reloc_tree)
4609 return;
4610
4611 root = root->reloc_root;
4612 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4613 /*
4614 * relocation is in the stage of merging trees. the space
4615 * used by merging a reloc tree is twice the size of
4616 * relocated tree nodes in the worst case. half for cowing
4617 * the reloc tree, half for cowing the fs tree. the space
4618 * used by cowing the reloc tree will be freed after the
4619 * tree is dropped. if we create snapshot, cowing the fs
4620 * tree may use more space than it frees. so we need
4621 * reserve extra space.
4622 */
4623 *bytes_to_reserve += rc->nodes_relocated;
4624}
4625
4626/*
4627 * called after snapshot is created. migrate block reservation
4628 * and create reloc root for the newly created snapshot
4629 */
4630int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4631 struct btrfs_pending_snapshot *pending)
4632{
4633 struct btrfs_root *root = pending->root;
4634 struct btrfs_root *reloc_root;
4635 struct btrfs_root *new_root;
4636 struct reloc_control *rc;
4637 int ret;
4638
4639 if (!root->reloc_root)
4640 return 0;
4641
4642 rc = root->fs_info->reloc_ctl;
4643 rc->merging_rsv_size += rc->nodes_relocated;
4644
4645 if (rc->merge_reloc_tree) {
4646 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4647 rc->block_rsv,
4648 rc->nodes_relocated);
4649 if (ret)
4650 return ret;
4651 }
4652
4653 new_root = pending->snap;
4654 reloc_root = create_reloc_root(trans, root->reloc_root,
4655 new_root->root_key.objectid);
4656 if (IS_ERR(reloc_root))
4657 return PTR_ERR(reloc_root);
4658
4659 ret = __add_reloc_root(reloc_root);
4660 BUG_ON(ret < 0);
4661 new_root->reloc_root = reloc_root;
4662
4663 if (rc->create_reloc_tree)
4664 ret = clone_backref_node(trans, rc, root, reloc_root);
4665 return ret;
4666}