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