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