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btrfs: constify map parameter for nr_parity_stripes and nr_data_stripes
[linux/fpc-iii.git] / fs / btrfs / relocation.c
blob22a3c69864fac6fb4d771c67d41da6a6e19e8a5c
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 "ctree.h"
13 #include "disk-io.h"
14 #include "transaction.h"
15 #include "volumes.h"
16 #include "locking.h"
17 #include "btrfs_inode.h"
18 #include "async-thread.h"
19 #include "free-space-cache.h"
20 #include "inode-map.h"
21 #include "qgroup.h"
22 #include "print-tree.h"
23
24 /*
25 * backref_node, mapping_node and tree_block start with this
26 */
27 struct tree_entry {
28 struct rb_node rb_node;
29 u64 bytenr;
30 };
31
32 /*
33 * present a tree block in the backref cache
34 */
35 struct backref_node {
36 struct rb_node rb_node;
37 u64 bytenr;
38
39 u64 new_bytenr;
40 /* objectid of tree block owner, can be not uptodate */
41 u64 owner;
42 /* link to pending, changed or detached list */
43 struct list_head list;
44 /* list of upper level blocks reference this block */
45 struct list_head upper;
46 /* list of child blocks in the cache */
47 struct list_head lower;
48 /* NULL if this node is not tree root */
49 struct btrfs_root *root;
50 /* extent buffer got by COW the block */
51 struct extent_buffer *eb;
52 /* level of tree block */
53 unsigned int level:8;
54 /* is the block in non-reference counted tree */
55 unsigned int cowonly:1;
56 /* 1 if no child node in the cache */
57 unsigned int lowest:1;
58 /* is the extent buffer locked */
59 unsigned int locked:1;
60 /* has the block been processed */
61 unsigned int processed:1;
62 /* have backrefs of this block been checked */
63 unsigned int checked:1;
64 /*
65 * 1 if corresponding block has been cowed but some upper
66 * level block pointers may not point to the new location
67 */
68 unsigned int pending:1;
69 /*
70 * 1 if the backref node isn't connected to any other
71 * backref node.
72 */
73 unsigned int detached:1;
74 };
75
76 /*
77 * present a block pointer in the backref cache
78 */
79 struct backref_edge {
80 struct list_head list[2];
81 struct backref_node *node[2];
82 };
83
84 #define LOWER 0
85 #define UPPER 1
86 #define RELOCATION_RESERVED_NODES 256
87
88 struct backref_cache {
89 /* red black tree of all backref nodes in the cache */
90 struct rb_root rb_root;
91 /* for passing backref nodes to btrfs_reloc_cow_block */
92 struct backref_node *path[BTRFS_MAX_LEVEL];
93 /*
94 * list of blocks that have been cowed but some block
95 * pointers in upper level blocks may not reflect the
96 * new location
97 */
98 struct list_head pending[BTRFS_MAX_LEVEL];
99 /* list of backref nodes with no child node */
100 struct list_head leaves;
101 /* list of blocks that have been cowed in current transaction */
102 struct list_head changed;
103 /* list of detached backref node. */
104 struct list_head detached;
105
106 u64 last_trans;
107
108 int nr_nodes;
109 int nr_edges;
110 };
111
112 /*
113 * map address of tree root to tree
114 */
115 struct mapping_node {
116 struct rb_node rb_node;
117 u64 bytenr;
118 void *data;
119 };
120
121 struct mapping_tree {
122 struct rb_root rb_root;
123 spinlock_t lock;
124 };
125
126 /*
127 * present a tree block to process
128 */
129 struct tree_block {
130 struct rb_node rb_node;
131 u64 bytenr;
132 struct btrfs_key key;
133 unsigned int level:8;
134 unsigned int key_ready:1;
135 };
136
137 #define MAX_EXTENTS 128
138
139 struct file_extent_cluster {
140 u64 start;
141 u64 end;
142 u64 boundary[MAX_EXTENTS];
143 unsigned int nr;
144 };
145
146 struct reloc_control {
147 /* block group to relocate */
148 struct btrfs_block_group_cache *block_group;
149 /* extent tree */
150 struct btrfs_root *extent_root;
151 /* inode for moving data */
152 struct inode *data_inode;
153
154 struct btrfs_block_rsv *block_rsv;
155
156 struct backref_cache backref_cache;
157
158 struct file_extent_cluster cluster;
159 /* tree blocks have been processed */
160 struct extent_io_tree processed_blocks;
161 /* map start of tree root to corresponding reloc tree */
162 struct mapping_tree reloc_root_tree;
163 /* list of reloc trees */
164 struct list_head reloc_roots;
165 /* list of subvolume trees that get relocated */
166 struct list_head dirty_subvol_roots;
167 /* size of metadata reservation for merging reloc trees */
168 u64 merging_rsv_size;
169 /* size of relocated tree nodes */
170 u64 nodes_relocated;
171 /* reserved size for block group relocation*/
172 u64 reserved_bytes;
173
174 u64 search_start;
175 u64 extents_found;
176
177 unsigned int stage:8;
178 unsigned int create_reloc_tree:1;
179 unsigned int merge_reloc_tree:1;
180 unsigned int found_file_extent:1;
181 };
182
183 /* stages of data relocation */
184 #define MOVE_DATA_EXTENTS 0
185 #define UPDATE_DATA_PTRS 1
186
187 static void remove_backref_node(struct backref_cache *cache,
188 struct backref_node *node);
189 static void __mark_block_processed(struct reloc_control *rc,
190 struct backref_node *node);
191
192 static void mapping_tree_init(struct mapping_tree *tree)
193 {
194 tree->rb_root = RB_ROOT;
195 spin_lock_init(&tree->lock);
196 }
197
198 static void backref_cache_init(struct backref_cache *cache)
199 {
200 int i;
201 cache->rb_root = RB_ROOT;
202 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
203 INIT_LIST_HEAD(&cache->pending[i]);
204 INIT_LIST_HEAD(&cache->changed);
205 INIT_LIST_HEAD(&cache->detached);
206 INIT_LIST_HEAD(&cache->leaves);
207 }
208
209 static void backref_cache_cleanup(struct backref_cache *cache)
210 {
211 struct backref_node *node;
212 int i;
213
214 while (!list_empty(&cache->detached)) {
215 node = list_entry(cache->detached.next,
216 struct backref_node, list);
217 remove_backref_node(cache, node);
218 }
219
220 while (!list_empty(&cache->leaves)) {
221 node = list_entry(cache->leaves.next,
222 struct backref_node, lower);
223 remove_backref_node(cache, node);
224 }
225
226 cache->last_trans = 0;
227
228 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
229 ASSERT(list_empty(&cache->pending[i]));
230 ASSERT(list_empty(&cache->changed));
231 ASSERT(list_empty(&cache->detached));
232 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
233 ASSERT(!cache->nr_nodes);
234 ASSERT(!cache->nr_edges);
235 }
236
237 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
238 {
239 struct backref_node *node;
240
241 node = kzalloc(sizeof(*node), GFP_NOFS);
242 if (node) {
243 INIT_LIST_HEAD(&node->list);
244 INIT_LIST_HEAD(&node->upper);
245 INIT_LIST_HEAD(&node->lower);
246 RB_CLEAR_NODE(&node->rb_node);
247 cache->nr_nodes++;
248 }
249 return node;
250 }
251
252 static void free_backref_node(struct backref_cache *cache,
253 struct backref_node *node)
254 {
255 if (node) {
256 cache->nr_nodes--;
257 kfree(node);
258 }
259 }
260
261 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
262 {
263 struct backref_edge *edge;
264
265 edge = kzalloc(sizeof(*edge), GFP_NOFS);
266 if (edge)
267 cache->nr_edges++;
268 return edge;
269 }
270
271 static void free_backref_edge(struct backref_cache *cache,
272 struct backref_edge *edge)
273 {
274 if (edge) {
275 cache->nr_edges--;
276 kfree(edge);
277 }
278 }
279
280 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
281 struct rb_node *node)
282 {
283 struct rb_node **p = &root->rb_node;
284 struct rb_node *parent = NULL;
285 struct tree_entry *entry;
286
287 while (*p) {
288 parent = *p;
289 entry = rb_entry(parent, struct tree_entry, rb_node);
290
291 if (bytenr < entry->bytenr)
292 p = &(*p)->rb_left;
293 else if (bytenr > entry->bytenr)
294 p = &(*p)->rb_right;
295 else
296 return parent;
297 }
298
299 rb_link_node(node, parent, p);
300 rb_insert_color(node, root);
301 return NULL;
302 }
303
304 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
305 {
306 struct rb_node *n = root->rb_node;
307 struct tree_entry *entry;
308
309 while (n) {
310 entry = rb_entry(n, struct tree_entry, rb_node);
311
312 if (bytenr < entry->bytenr)
313 n = n->rb_left;
314 else if (bytenr > entry->bytenr)
315 n = n->rb_right;
316 else
317 return n;
318 }
319 return NULL;
320 }
321
322 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
323 {
324
325 struct btrfs_fs_info *fs_info = NULL;
326 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
327 rb_node);
328 if (bnode->root)
329 fs_info = bnode->root->fs_info;
330 btrfs_panic(fs_info, errno,
331 "Inconsistency in backref cache found at offset %llu",
332 bytenr);
333 }
334
335 /*
336 * walk up backref nodes until reach node presents tree root
337 */
338 static struct backref_node *walk_up_backref(struct backref_node *node,
339 struct backref_edge *edges[],
340 int *index)
341 {
342 struct backref_edge *edge;
343 int idx = *index;
344
345 while (!list_empty(&node->upper)) {
346 edge = list_entry(node->upper.next,
347 struct backref_edge, list[LOWER]);
348 edges[idx++] = edge;
349 node = edge->node[UPPER];
350 }
351 BUG_ON(node->detached);
352 *index = idx;
353 return node;
354 }
355
356 /*
357 * walk down backref nodes to find start of next reference path
358 */
359 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
360 int *index)
361 {
362 struct backref_edge *edge;
363 struct backref_node *lower;
364 int idx = *index;
365
366 while (idx > 0) {
367 edge = edges[idx - 1];
368 lower = edge->node[LOWER];
369 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
370 idx--;
371 continue;
372 }
373 edge = list_entry(edge->list[LOWER].next,
374 struct backref_edge, list[LOWER]);
375 edges[idx - 1] = edge;
376 *index = idx;
377 return edge->node[UPPER];
378 }
379 *index = 0;
380 return NULL;
381 }
382
383 static void unlock_node_buffer(struct backref_node *node)
384 {
385 if (node->locked) {
386 btrfs_tree_unlock(node->eb);
387 node->locked = 0;
388 }
389 }
390
391 static void drop_node_buffer(struct backref_node *node)
392 {
393 if (node->eb) {
394 unlock_node_buffer(node);
395 free_extent_buffer(node->eb);
396 node->eb = NULL;
397 }
398 }
399
400 static void drop_backref_node(struct backref_cache *tree,
401 struct backref_node *node)
402 {
403 BUG_ON(!list_empty(&node->upper));
404
405 drop_node_buffer(node);
406 list_del(&node->list);
407 list_del(&node->lower);
408 if (!RB_EMPTY_NODE(&node->rb_node))
409 rb_erase(&node->rb_node, &tree->rb_root);
410 free_backref_node(tree, node);
411 }
412
413 /*
414 * remove a backref node from the backref cache
415 */
416 static void remove_backref_node(struct backref_cache *cache,
417 struct backref_node *node)
418 {
419 struct backref_node *upper;
420 struct backref_edge *edge;
421
422 if (!node)
423 return;
424
425 BUG_ON(!node->lowest && !node->detached);
426 while (!list_empty(&node->upper)) {
427 edge = list_entry(node->upper.next, struct backref_edge,
428 list[LOWER]);
429 upper = edge->node[UPPER];
430 list_del(&edge->list[LOWER]);
431 list_del(&edge->list[UPPER]);
432 free_backref_edge(cache, edge);
433
434 if (RB_EMPTY_NODE(&upper->rb_node)) {
435 BUG_ON(!list_empty(&node->upper));
436 drop_backref_node(cache, node);
437 node = upper;
438 node->lowest = 1;
439 continue;
440 }
441 /*
442 * add the node to leaf node list if no other
443 * child block cached.
444 */
445 if (list_empty(&upper->lower)) {
446 list_add_tail(&upper->lower, &cache->leaves);
447 upper->lowest = 1;
448 }
449 }
450
451 drop_backref_node(cache, node);
452 }
453
454 static void update_backref_node(struct backref_cache *cache,
455 struct backref_node *node, u64 bytenr)
456 {
457 struct rb_node *rb_node;
458 rb_erase(&node->rb_node, &cache->rb_root);
459 node->bytenr = bytenr;
460 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
461 if (rb_node)
462 backref_tree_panic(rb_node, -EEXIST, bytenr);
463 }
464
465 /*
466 * update backref cache after a transaction commit
467 */
468 static int update_backref_cache(struct btrfs_trans_handle *trans,
469 struct backref_cache *cache)
470 {
471 struct backref_node *node;
472 int level = 0;
473
474 if (cache->last_trans == 0) {
475 cache->last_trans = trans->transid;
476 return 0;
477 }
478
479 if (cache->last_trans == trans->transid)
480 return 0;
481
482 /*
483 * detached nodes are used to avoid unnecessary backref
484 * lookup. transaction commit changes the extent tree.
485 * so the detached nodes are no longer useful.
486 */
487 while (!list_empty(&cache->detached)) {
488 node = list_entry(cache->detached.next,
489 struct backref_node, list);
490 remove_backref_node(cache, node);
491 }
492
493 while (!list_empty(&cache->changed)) {
494 node = list_entry(cache->changed.next,
495 struct backref_node, list);
496 list_del_init(&node->list);
497 BUG_ON(node->pending);
498 update_backref_node(cache, node, node->new_bytenr);
499 }
500
501 /*
502 * some nodes can be left in the pending list if there were
503 * errors during processing the pending nodes.
504 */
505 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
506 list_for_each_entry(node, &cache->pending[level], list) {
507 BUG_ON(!node->pending);
508 if (node->bytenr == node->new_bytenr)
509 continue;
510 update_backref_node(cache, node, node->new_bytenr);
511 }
512 }
513
514 cache->last_trans = 0;
515 return 1;
516 }
517
518
519 static int should_ignore_root(struct btrfs_root *root)
520 {
521 struct btrfs_root *reloc_root;
522
523 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
524 return 0;
525
526 reloc_root = root->reloc_root;
527 if (!reloc_root)
528 return 0;
529
530 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
531 root->fs_info->running_transaction->transid - 1)
532 return 0;
533 /*
534 * if there is reloc tree and it was created in previous
535 * transaction backref lookup can find the reloc tree,
536 * so backref node for the fs tree root is useless for
537 * relocation.
538 */
539 return 1;
540 }
541 /*
542 * find reloc tree by address of tree root
543 */
544 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
545 u64 bytenr)
546 {
547 struct rb_node *rb_node;
548 struct mapping_node *node;
549 struct btrfs_root *root = NULL;
550
551 spin_lock(&rc->reloc_root_tree.lock);
552 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
553 if (rb_node) {
554 node = rb_entry(rb_node, struct mapping_node, rb_node);
555 root = (struct btrfs_root *)node->data;
556 }
557 spin_unlock(&rc->reloc_root_tree.lock);
558 return root;
559 }
560
561 static int is_cowonly_root(u64 root_objectid)
562 {
563 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
564 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
565 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
566 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
567 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
568 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
569 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
570 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
571 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
572 return 1;
573 return 0;
574 }
575
576 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
577 u64 root_objectid)
578 {
579 struct btrfs_key key;
580
581 key.objectid = root_objectid;
582 key.type = BTRFS_ROOT_ITEM_KEY;
583 if (is_cowonly_root(root_objectid))
584 key.offset = 0;
585 else
586 key.offset = (u64)-1;
587
588 return btrfs_get_fs_root(fs_info, &key, false);
589 }
590
591 static noinline_for_stack
592 int find_inline_backref(struct extent_buffer *leaf, int slot,
593 unsigned long *ptr, unsigned long *end)
594 {
595 struct btrfs_key key;
596 struct btrfs_extent_item *ei;
597 struct btrfs_tree_block_info *bi;
598 u32 item_size;
599
600 btrfs_item_key_to_cpu(leaf, &key, slot);
601
602 item_size = btrfs_item_size_nr(leaf, slot);
603 if (item_size < sizeof(*ei)) {
604 btrfs_print_v0_err(leaf->fs_info);
605 btrfs_handle_fs_error(leaf->fs_info, -EINVAL, NULL);
606 return 1;
607 }
608 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
609 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
610 BTRFS_EXTENT_FLAG_TREE_BLOCK));
611
612 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
613 item_size <= sizeof(*ei) + sizeof(*bi)) {
614 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
615 return 1;
616 }
617 if (key.type == BTRFS_METADATA_ITEM_KEY &&
618 item_size <= sizeof(*ei)) {
619 WARN_ON(item_size < sizeof(*ei));
620 return 1;
621 }
622
623 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
624 bi = (struct btrfs_tree_block_info *)(ei + 1);
625 *ptr = (unsigned long)(bi + 1);
626 } else {
627 *ptr = (unsigned long)(ei + 1);
628 }
629 *end = (unsigned long)ei + item_size;
630 return 0;
631 }
632
633 /*
634 * build backref tree for a given tree block. root of the backref tree
635 * corresponds the tree block, leaves of the backref tree correspond
636 * roots of b-trees that reference the tree block.
637 *
638 * the basic idea of this function is check backrefs of a given block
639 * to find upper level blocks that reference the block, and then check
640 * backrefs of these upper level blocks recursively. the recursion stop
641 * when tree root is reached or backrefs for the block is cached.
642 *
643 * NOTE: if we find backrefs for a block are cached, we know backrefs
644 * for all upper level blocks that directly/indirectly reference the
645 * block are also cached.
646 */
647 static noinline_for_stack
648 struct backref_node *build_backref_tree(struct reloc_control *rc,
649 struct btrfs_key *node_key,
650 int level, u64 bytenr)
651 {
652 struct backref_cache *cache = &rc->backref_cache;
653 struct btrfs_path *path1; /* For searching extent root */
654 struct btrfs_path *path2; /* For searching parent of TREE_BLOCK_REF */
655 struct extent_buffer *eb;
656 struct btrfs_root *root;
657 struct backref_node *cur;
658 struct backref_node *upper;
659 struct backref_node *lower;
660 struct backref_node *node = NULL;
661 struct backref_node *exist = NULL;
662 struct backref_edge *edge;
663 struct rb_node *rb_node;
664 struct btrfs_key key;
665 unsigned long end;
666 unsigned long ptr;
667 LIST_HEAD(list); /* Pending edge list, upper node needs to be checked */
668 LIST_HEAD(useless);
669 int cowonly;
670 int ret;
671 int err = 0;
672 bool need_check = true;
673
674 path1 = btrfs_alloc_path();
675 path2 = btrfs_alloc_path();
676 if (!path1 || !path2) {
677 err = -ENOMEM;
678 goto out;
679 }
680 path1->reada = READA_FORWARD;
681 path2->reada = READA_FORWARD;
682
683 node = alloc_backref_node(cache);
684 if (!node) {
685 err = -ENOMEM;
686 goto out;
687 }
688
689 node->bytenr = bytenr;
690 node->level = level;
691 node->lowest = 1;
692 cur = node;
693 again:
694 end = 0;
695 ptr = 0;
696 key.objectid = cur->bytenr;
697 key.type = BTRFS_METADATA_ITEM_KEY;
698 key.offset = (u64)-1;
699
700 path1->search_commit_root = 1;
701 path1->skip_locking = 1;
702 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
703 0, 0);
704 if (ret < 0) {
705 err = ret;
706 goto out;
707 }
708 ASSERT(ret);
709 ASSERT(path1->slots[0]);
710
711 path1->slots[0]--;
712
713 WARN_ON(cur->checked);
714 if (!list_empty(&cur->upper)) {
715 /*
716 * the backref was added previously when processing
717 * backref of type BTRFS_TREE_BLOCK_REF_KEY
718 */
719 ASSERT(list_is_singular(&cur->upper));
720 edge = list_entry(cur->upper.next, struct backref_edge,
721 list[LOWER]);
722 ASSERT(list_empty(&edge->list[UPPER]));
723 exist = edge->node[UPPER];
724 /*
725 * add the upper level block to pending list if we need
726 * check its backrefs
727 */
728 if (!exist->checked)
729 list_add_tail(&edge->list[UPPER], &list);
730 } else {
731 exist = NULL;
732 }
733
734 while (1) {
735 cond_resched();
736 eb = path1->nodes[0];
737
738 if (ptr >= end) {
739 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
740 ret = btrfs_next_leaf(rc->extent_root, path1);
741 if (ret < 0) {
742 err = ret;
743 goto out;
744 }
745 if (ret > 0)
746 break;
747 eb = path1->nodes[0];
748 }
749
750 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
751 if (key.objectid != cur->bytenr) {
752 WARN_ON(exist);
753 break;
754 }
755
756 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
757 key.type == BTRFS_METADATA_ITEM_KEY) {
758 ret = find_inline_backref(eb, path1->slots[0],
759 &ptr, &end);
760 if (ret)
761 goto next;
762 }
763 }
764
765 if (ptr < end) {
766 /* update key for inline back ref */
767 struct btrfs_extent_inline_ref *iref;
768 int type;
769 iref = (struct btrfs_extent_inline_ref *)ptr;
770 type = btrfs_get_extent_inline_ref_type(eb, iref,
771 BTRFS_REF_TYPE_BLOCK);
772 if (type == BTRFS_REF_TYPE_INVALID) {
773 err = -EUCLEAN;
774 goto out;
775 }
776 key.type = type;
777 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
778
779 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
780 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
781 }
782
783 /*
784 * Parent node found and matches current inline ref, no need to
785 * rebuild this node for this inline ref.
786 */
787 if (exist &&
788 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
789 exist->owner == key.offset) ||
790 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
791 exist->bytenr == key.offset))) {
792 exist = NULL;
793 goto next;
794 }
795
796 /* SHARED_BLOCK_REF means key.offset is the parent bytenr */
797 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
798 if (key.objectid == key.offset) {
799 /*
800 * Only root blocks of reloc trees use backref
801 * pointing to itself.
802 */
803 root = find_reloc_root(rc, cur->bytenr);
804 ASSERT(root);
805 cur->root = root;
806 break;
807 }
808
809 edge = alloc_backref_edge(cache);
810 if (!edge) {
811 err = -ENOMEM;
812 goto out;
813 }
814 rb_node = tree_search(&cache->rb_root, key.offset);
815 if (!rb_node) {
816 upper = alloc_backref_node(cache);
817 if (!upper) {
818 free_backref_edge(cache, edge);
819 err = -ENOMEM;
820 goto out;
821 }
822 upper->bytenr = key.offset;
823 upper->level = cur->level + 1;
824 /*
825 * backrefs for the upper level block isn't
826 * cached, add the block to pending list
827 */
828 list_add_tail(&edge->list[UPPER], &list);
829 } else {
830 upper = rb_entry(rb_node, struct backref_node,
831 rb_node);
832 ASSERT(upper->checked);
833 INIT_LIST_HEAD(&edge->list[UPPER]);
834 }
835 list_add_tail(&edge->list[LOWER], &cur->upper);
836 edge->node[LOWER] = cur;
837 edge->node[UPPER] = upper;
838
839 goto next;
840 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
841 err = -EINVAL;
842 btrfs_print_v0_err(rc->extent_root->fs_info);
843 btrfs_handle_fs_error(rc->extent_root->fs_info, err,
844 NULL);
845 goto out;
846 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
847 goto next;
848 }
849
850 /*
851 * key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset
852 * means the root objectid. We need to search the tree to get
853 * its parent bytenr.
854 */
855 root = read_fs_root(rc->extent_root->fs_info, key.offset);
856 if (IS_ERR(root)) {
857 err = PTR_ERR(root);
858 goto out;
859 }
860
861 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
862 cur->cowonly = 1;
863
864 if (btrfs_root_level(&root->root_item) == cur->level) {
865 /* tree root */
866 ASSERT(btrfs_root_bytenr(&root->root_item) ==
867 cur->bytenr);
868 if (should_ignore_root(root))
869 list_add(&cur->list, &useless);
870 else
871 cur->root = root;
872 break;
873 }
874
875 level = cur->level + 1;
876
877 /* Search the tree to find parent blocks referring the block. */
878 path2->search_commit_root = 1;
879 path2->skip_locking = 1;
880 path2->lowest_level = level;
881 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
882 path2->lowest_level = 0;
883 if (ret < 0) {
884 err = ret;
885 goto out;
886 }
887 if (ret > 0 && path2->slots[level] > 0)
888 path2->slots[level]--;
889
890 eb = path2->nodes[level];
891 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
892 cur->bytenr) {
893 btrfs_err(root->fs_info,
894 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
895 cur->bytenr, level - 1,
896 root->root_key.objectid,
897 node_key->objectid, node_key->type,
898 node_key->offset);
899 err = -ENOENT;
900 goto out;
901 }
902 lower = cur;
903 need_check = true;
904
905 /* Add all nodes and edges in the path */
906 for (; level < BTRFS_MAX_LEVEL; level++) {
907 if (!path2->nodes[level]) {
908 ASSERT(btrfs_root_bytenr(&root->root_item) ==
909 lower->bytenr);
910 if (should_ignore_root(root))
911 list_add(&lower->list, &useless);
912 else
913 lower->root = root;
914 break;
915 }
916
917 edge = alloc_backref_edge(cache);
918 if (!edge) {
919 err = -ENOMEM;
920 goto out;
921 }
922
923 eb = path2->nodes[level];
924 rb_node = tree_search(&cache->rb_root, eb->start);
925 if (!rb_node) {
926 upper = alloc_backref_node(cache);
927 if (!upper) {
928 free_backref_edge(cache, edge);
929 err = -ENOMEM;
930 goto out;
931 }
932 upper->bytenr = eb->start;
933 upper->owner = btrfs_header_owner(eb);
934 upper->level = lower->level + 1;
935 if (!test_bit(BTRFS_ROOT_REF_COWS,
936 &root->state))
937 upper->cowonly = 1;
938
939 /*
940 * if we know the block isn't shared
941 * we can void checking its backrefs.
942 */
943 if (btrfs_block_can_be_shared(root, eb))
944 upper->checked = 0;
945 else
946 upper->checked = 1;
947
948 /*
949 * add the block to pending list if we
950 * need check its backrefs, we only do this once
951 * while walking up a tree as we will catch
952 * anything else later on.
953 */
954 if (!upper->checked && need_check) {
955 need_check = false;
956 list_add_tail(&edge->list[UPPER],
957 &list);
958 } else {
959 if (upper->checked)
960 need_check = true;
961 INIT_LIST_HEAD(&edge->list[UPPER]);
962 }
963 } else {
964 upper = rb_entry(rb_node, struct backref_node,
965 rb_node);
966 ASSERT(upper->checked);
967 INIT_LIST_HEAD(&edge->list[UPPER]);
968 if (!upper->owner)
969 upper->owner = btrfs_header_owner(eb);
970 }
971 list_add_tail(&edge->list[LOWER], &lower->upper);
972 edge->node[LOWER] = lower;
973 edge->node[UPPER] = upper;
974
975 if (rb_node)
976 break;
977 lower = upper;
978 upper = NULL;
979 }
980 btrfs_release_path(path2);
981 next:
982 if (ptr < end) {
983 ptr += btrfs_extent_inline_ref_size(key.type);
984 if (ptr >= end) {
985 WARN_ON(ptr > end);
986 ptr = 0;
987 end = 0;
988 }
989 }
990 if (ptr >= end)
991 path1->slots[0]++;
992 }
993 btrfs_release_path(path1);
994
995 cur->checked = 1;
996 WARN_ON(exist);
997
998 /* the pending list isn't empty, take the first block to process */
999 if (!list_empty(&list)) {
1000 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1001 list_del_init(&edge->list[UPPER]);
1002 cur = edge->node[UPPER];
1003 goto again;
1004 }
1005
1006 /*
1007 * everything goes well, connect backref nodes and insert backref nodes
1008 * into the cache.
1009 */
1010 ASSERT(node->checked);
1011 cowonly = node->cowonly;
1012 if (!cowonly) {
1013 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1014 &node->rb_node);
1015 if (rb_node)
1016 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1017 list_add_tail(&node->lower, &cache->leaves);
1018 }
1019
1020 list_for_each_entry(edge, &node->upper, list[LOWER])
1021 list_add_tail(&edge->list[UPPER], &list);
1022
1023 while (!list_empty(&list)) {
1024 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1025 list_del_init(&edge->list[UPPER]);
1026 upper = edge->node[UPPER];
1027 if (upper->detached) {
1028 list_del(&edge->list[LOWER]);
1029 lower = edge->node[LOWER];
1030 free_backref_edge(cache, edge);
1031 if (list_empty(&lower->upper))
1032 list_add(&lower->list, &useless);
1033 continue;
1034 }
1035
1036 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1037 if (upper->lowest) {
1038 list_del_init(&upper->lower);
1039 upper->lowest = 0;
1040 }
1041
1042 list_add_tail(&edge->list[UPPER], &upper->lower);
1043 continue;
1044 }
1045
1046 if (!upper->checked) {
1047 /*
1048 * Still want to blow up for developers since this is a
1049 * logic bug.
1050 */
1051 ASSERT(0);
1052 err = -EINVAL;
1053 goto out;
1054 }
1055 if (cowonly != upper->cowonly) {
1056 ASSERT(0);
1057 err = -EINVAL;
1058 goto out;
1059 }
1060
1061 if (!cowonly) {
1062 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1063 &upper->rb_node);
1064 if (rb_node)
1065 backref_tree_panic(rb_node, -EEXIST,
1066 upper->bytenr);
1067 }
1068
1069 list_add_tail(&edge->list[UPPER], &upper->lower);
1070
1071 list_for_each_entry(edge, &upper->upper, list[LOWER])
1072 list_add_tail(&edge->list[UPPER], &list);
1073 }
1074 /*
1075 * process useless backref nodes. backref nodes for tree leaves
1076 * are deleted from the cache. backref nodes for upper level
1077 * tree blocks are left in the cache to avoid unnecessary backref
1078 * lookup.
1079 */
1080 while (!list_empty(&useless)) {
1081 upper = list_entry(useless.next, struct backref_node, list);
1082 list_del_init(&upper->list);
1083 ASSERT(list_empty(&upper->upper));
1084 if (upper == node)
1085 node = NULL;
1086 if (upper->lowest) {
1087 list_del_init(&upper->lower);
1088 upper->lowest = 0;
1089 }
1090 while (!list_empty(&upper->lower)) {
1091 edge = list_entry(upper->lower.next,
1092 struct backref_edge, list[UPPER]);
1093 list_del(&edge->list[UPPER]);
1094 list_del(&edge->list[LOWER]);
1095 lower = edge->node[LOWER];
1096 free_backref_edge(cache, edge);
1097
1098 if (list_empty(&lower->upper))
1099 list_add(&lower->list, &useless);
1100 }
1101 __mark_block_processed(rc, upper);
1102 if (upper->level > 0) {
1103 list_add(&upper->list, &cache->detached);
1104 upper->detached = 1;
1105 } else {
1106 rb_erase(&upper->rb_node, &cache->rb_root);
1107 free_backref_node(cache, upper);
1108 }
1109 }
1110 out:
1111 btrfs_free_path(path1);
1112 btrfs_free_path(path2);
1113 if (err) {
1114 while (!list_empty(&useless)) {
1115 lower = list_entry(useless.next,
1116 struct backref_node, list);
1117 list_del_init(&lower->list);
1118 }
1119 while (!list_empty(&list)) {
1120 edge = list_first_entry(&list, struct backref_edge,
1121 list[UPPER]);
1122 list_del(&edge->list[UPPER]);
1123 list_del(&edge->list[LOWER]);
1124 lower = edge->node[LOWER];
1125 upper = edge->node[UPPER];
1126 free_backref_edge(cache, edge);
1127
1128 /*
1129 * Lower is no longer linked to any upper backref nodes
1130 * and isn't in the cache, we can free it ourselves.
1131 */
1132 if (list_empty(&lower->upper) &&
1133 RB_EMPTY_NODE(&lower->rb_node))
1134 list_add(&lower->list, &useless);
1135
1136 if (!RB_EMPTY_NODE(&upper->rb_node))
1137 continue;
1138
1139 /* Add this guy's upper edges to the list to process */
1140 list_for_each_entry(edge, &upper->upper, list[LOWER])
1141 list_add_tail(&edge->list[UPPER], &list);
1142 if (list_empty(&upper->upper))
1143 list_add(&upper->list, &useless);
1144 }
1145
1146 while (!list_empty(&useless)) {
1147 lower = list_entry(useless.next,
1148 struct backref_node, list);
1149 list_del_init(&lower->list);
1150 if (lower == node)
1151 node = NULL;
1152 free_backref_node(cache, lower);
1153 }
1154
1155 free_backref_node(cache, node);
1156 return ERR_PTR(err);
1157 }
1158 ASSERT(!node || !node->detached);
1159 return node;
1160 }
1161
1162 /*
1163 * helper to add backref node for the newly created snapshot.
1164 * the backref node is created by cloning backref node that
1165 * corresponds to root of source tree
1166 */
1167 static int clone_backref_node(struct btrfs_trans_handle *trans,
1168 struct reloc_control *rc,
1169 struct btrfs_root *src,
1170 struct btrfs_root *dest)
1171 {
1172 struct btrfs_root *reloc_root = src->reloc_root;
1173 struct backref_cache *cache = &rc->backref_cache;
1174 struct backref_node *node = NULL;
1175 struct backref_node *new_node;
1176 struct backref_edge *edge;
1177 struct backref_edge *new_edge;
1178 struct rb_node *rb_node;
1179
1180 if (cache->last_trans > 0)
1181 update_backref_cache(trans, cache);
1182
1183 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1184 if (rb_node) {
1185 node = rb_entry(rb_node, struct backref_node, rb_node);
1186 if (node->detached)
1187 node = NULL;
1188 else
1189 BUG_ON(node->new_bytenr != reloc_root->node->start);
1190 }
1191
1192 if (!node) {
1193 rb_node = tree_search(&cache->rb_root,
1194 reloc_root->commit_root->start);
1195 if (rb_node) {
1196 node = rb_entry(rb_node, struct backref_node,
1197 rb_node);
1198 BUG_ON(node->detached);
1199 }
1200 }
1201
1202 if (!node)
1203 return 0;
1204
1205 new_node = alloc_backref_node(cache);
1206 if (!new_node)
1207 return -ENOMEM;
1208
1209 new_node->bytenr = dest->node->start;
1210 new_node->level = node->level;
1211 new_node->lowest = node->lowest;
1212 new_node->checked = 1;
1213 new_node->root = dest;
1214
1215 if (!node->lowest) {
1216 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1217 new_edge = alloc_backref_edge(cache);
1218 if (!new_edge)
1219 goto fail;
1220
1221 new_edge->node[UPPER] = new_node;
1222 new_edge->node[LOWER] = edge->node[LOWER];
1223 list_add_tail(&new_edge->list[UPPER],
1224 &new_node->lower);
1225 }
1226 } else {
1227 list_add_tail(&new_node->lower, &cache->leaves);
1228 }
1229
1230 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1231 &new_node->rb_node);
1232 if (rb_node)
1233 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1234
1235 if (!new_node->lowest) {
1236 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1237 list_add_tail(&new_edge->list[LOWER],
1238 &new_edge->node[LOWER]->upper);
1239 }
1240 }
1241 return 0;
1242 fail:
1243 while (!list_empty(&new_node->lower)) {
1244 new_edge = list_entry(new_node->lower.next,
1245 struct backref_edge, list[UPPER]);
1246 list_del(&new_edge->list[UPPER]);
1247 free_backref_edge(cache, new_edge);
1248 }
1249 free_backref_node(cache, new_node);
1250 return -ENOMEM;
1251 }
1252
1253 /*
1254 * helper to add 'address of tree root -> reloc tree' mapping
1255 */
1256 static int __must_check __add_reloc_root(struct btrfs_root *root)
1257 {
1258 struct btrfs_fs_info *fs_info = root->fs_info;
1259 struct rb_node *rb_node;
1260 struct mapping_node *node;
1261 struct reloc_control *rc = fs_info->reloc_ctl;
1262
1263 node = kmalloc(sizeof(*node), GFP_NOFS);
1264 if (!node)
1265 return -ENOMEM;
1266
1267 node->bytenr = root->node->start;
1268 node->data = root;
1269
1270 spin_lock(&rc->reloc_root_tree.lock);
1271 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1272 node->bytenr, &node->rb_node);
1273 spin_unlock(&rc->reloc_root_tree.lock);
1274 if (rb_node) {
1275 btrfs_panic(fs_info, -EEXIST,
1276 "Duplicate root found for start=%llu while inserting into relocation tree",
1277 node->bytenr);
1278 }
1279
1280 list_add_tail(&root->root_list, &rc->reloc_roots);
1281 return 0;
1282 }
1283
1284 /*
1285 * helper to delete the 'address of tree root -> reloc tree'
1286 * mapping
1287 */
1288 static void __del_reloc_root(struct btrfs_root *root)
1289 {
1290 struct btrfs_fs_info *fs_info = root->fs_info;
1291 struct rb_node *rb_node;
1292 struct mapping_node *node = NULL;
1293 struct reloc_control *rc = fs_info->reloc_ctl;
1294
1295 if (rc && root->node) {
1296 spin_lock(&rc->reloc_root_tree.lock);
1297 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1298 root->node->start);
1299 if (rb_node) {
1300 node = rb_entry(rb_node, struct mapping_node, rb_node);
1301 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1302 }
1303 spin_unlock(&rc->reloc_root_tree.lock);
1304 if (!node)
1305 return;
1306 BUG_ON((struct btrfs_root *)node->data != root);
1307 }
1308
1309 spin_lock(&fs_info->trans_lock);
1310 list_del_init(&root->root_list);
1311 spin_unlock(&fs_info->trans_lock);
1312 kfree(node);
1313 }
1314
1315 /*
1316 * helper to update the 'address of tree root -> reloc tree'
1317 * mapping
1318 */
1319 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1320 {
1321 struct btrfs_fs_info *fs_info = root->fs_info;
1322 struct rb_node *rb_node;
1323 struct mapping_node *node = NULL;
1324 struct reloc_control *rc = fs_info->reloc_ctl;
1325
1326 spin_lock(&rc->reloc_root_tree.lock);
1327 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1328 root->node->start);
1329 if (rb_node) {
1330 node = rb_entry(rb_node, struct mapping_node, rb_node);
1331 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1332 }
1333 spin_unlock(&rc->reloc_root_tree.lock);
1334
1335 if (!node)
1336 return 0;
1337 BUG_ON((struct btrfs_root *)node->data != root);
1338
1339 spin_lock(&rc->reloc_root_tree.lock);
1340 node->bytenr = new_bytenr;
1341 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1342 node->bytenr, &node->rb_node);
1343 spin_unlock(&rc->reloc_root_tree.lock);
1344 if (rb_node)
1345 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1346 return 0;
1347 }
1348
1349 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1350 struct btrfs_root *root, u64 objectid)
1351 {
1352 struct btrfs_fs_info *fs_info = root->fs_info;
1353 struct btrfs_root *reloc_root;
1354 struct extent_buffer *eb;
1355 struct btrfs_root_item *root_item;
1356 struct btrfs_key root_key;
1357 int ret;
1358
1359 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1360 BUG_ON(!root_item);
1361
1362 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1363 root_key.type = BTRFS_ROOT_ITEM_KEY;
1364 root_key.offset = objectid;
1365
1366 if (root->root_key.objectid == objectid) {
1367 u64 commit_root_gen;
1368
1369 /* called by btrfs_init_reloc_root */
1370 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1371 BTRFS_TREE_RELOC_OBJECTID);
1372 BUG_ON(ret);
1373 /*
1374 * Set the last_snapshot field to the generation of the commit
1375 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1376 * correctly (returns true) when the relocation root is created
1377 * either inside the critical section of a transaction commit
1378 * (through transaction.c:qgroup_account_snapshot()) and when
1379 * it's created before the transaction commit is started.
1380 */
1381 commit_root_gen = btrfs_header_generation(root->commit_root);
1382 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1383 } else {
1384 /*
1385 * called by btrfs_reloc_post_snapshot_hook.
1386 * the source tree is a reloc tree, all tree blocks
1387 * modified after it was created have RELOC flag
1388 * set in their headers. so it's OK to not update
1389 * the 'last_snapshot'.
1390 */
1391 ret = btrfs_copy_root(trans, root, root->node, &eb,
1392 BTRFS_TREE_RELOC_OBJECTID);
1393 BUG_ON(ret);
1394 }
1395
1396 memcpy(root_item, &root->root_item, sizeof(*root_item));
1397 btrfs_set_root_bytenr(root_item, eb->start);
1398 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1399 btrfs_set_root_generation(root_item, trans->transid);
1400
1401 if (root->root_key.objectid == objectid) {
1402 btrfs_set_root_refs(root_item, 0);
1403 memset(&root_item->drop_progress, 0,
1404 sizeof(struct btrfs_disk_key));
1405 root_item->drop_level = 0;
1406 }
1407
1408 btrfs_tree_unlock(eb);
1409 free_extent_buffer(eb);
1410
1411 ret = btrfs_insert_root(trans, fs_info->tree_root,
1412 &root_key, root_item);
1413 BUG_ON(ret);
1414 kfree(root_item);
1415
1416 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1417 BUG_ON(IS_ERR(reloc_root));
1418 reloc_root->last_trans = trans->transid;
1419 return reloc_root;
1420 }
1421
1422 /*
1423 * create reloc tree for a given fs tree. reloc tree is just a
1424 * snapshot of the fs tree with special root objectid.
1425 */
1426 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1427 struct btrfs_root *root)
1428 {
1429 struct btrfs_fs_info *fs_info = root->fs_info;
1430 struct btrfs_root *reloc_root;
1431 struct reloc_control *rc = fs_info->reloc_ctl;
1432 struct btrfs_block_rsv *rsv;
1433 int clear_rsv = 0;
1434 int ret;
1435
1436 if (root->reloc_root) {
1437 reloc_root = root->reloc_root;
1438 reloc_root->last_trans = trans->transid;
1439 return 0;
1440 }
1441
1442 if (!rc || !rc->create_reloc_tree ||
1443 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1444 return 0;
1445
1446 if (!trans->reloc_reserved) {
1447 rsv = trans->block_rsv;
1448 trans->block_rsv = rc->block_rsv;
1449 clear_rsv = 1;
1450 }
1451 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1452 if (clear_rsv)
1453 trans->block_rsv = rsv;
1454
1455 ret = __add_reloc_root(reloc_root);
1456 BUG_ON(ret < 0);
1457 root->reloc_root = reloc_root;
1458 return 0;
1459 }
1460
1461 /*
1462 * update root item of reloc tree
1463 */
1464 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1465 struct btrfs_root *root)
1466 {
1467 struct btrfs_fs_info *fs_info = root->fs_info;
1468 struct btrfs_root *reloc_root;
1469 struct btrfs_root_item *root_item;
1470 int ret;
1471
1472 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state) ||
1473 !root->reloc_root)
1474 goto out;
1475
1476 reloc_root = root->reloc_root;
1477 root_item = &reloc_root->root_item;
1478
1479 /* root->reloc_root will stay until current relocation finished */
1480 if (fs_info->reloc_ctl->merge_reloc_tree &&
1481 btrfs_root_refs(root_item) == 0) {
1482 set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
1483 __del_reloc_root(reloc_root);
1484 }
1485
1486 if (reloc_root->commit_root != reloc_root->node) {
1487 btrfs_set_root_node(root_item, reloc_root->node);
1488 free_extent_buffer(reloc_root->commit_root);
1489 reloc_root->commit_root = btrfs_root_node(reloc_root);
1490 }
1491
1492 ret = btrfs_update_root(trans, fs_info->tree_root,
1493 &reloc_root->root_key, root_item);
1494 BUG_ON(ret);
1495
1496 out:
1497 return 0;
1498 }
1499
1500 /*
1501 * helper to find first cached inode with inode number >= objectid
1502 * in a subvolume
1503 */
1504 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1505 {
1506 struct rb_node *node;
1507 struct rb_node *prev;
1508 struct btrfs_inode *entry;
1509 struct inode *inode;
1510
1511 spin_lock(&root->inode_lock);
1512 again:
1513 node = root->inode_tree.rb_node;
1514 prev = NULL;
1515 while (node) {
1516 prev = node;
1517 entry = rb_entry(node, struct btrfs_inode, rb_node);
1518
1519 if (objectid < btrfs_ino(entry))
1520 node = node->rb_left;
1521 else if (objectid > btrfs_ino(entry))
1522 node = node->rb_right;
1523 else
1524 break;
1525 }
1526 if (!node) {
1527 while (prev) {
1528 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1529 if (objectid <= btrfs_ino(entry)) {
1530 node = prev;
1531 break;
1532 }
1533 prev = rb_next(prev);
1534 }
1535 }
1536 while (node) {
1537 entry = rb_entry(node, struct btrfs_inode, rb_node);
1538 inode = igrab(&entry->vfs_inode);
1539 if (inode) {
1540 spin_unlock(&root->inode_lock);
1541 return inode;
1542 }
1543
1544 objectid = btrfs_ino(entry) + 1;
1545 if (cond_resched_lock(&root->inode_lock))
1546 goto again;
1547
1548 node = rb_next(node);
1549 }
1550 spin_unlock(&root->inode_lock);
1551 return NULL;
1552 }
1553
1554 static int in_block_group(u64 bytenr,
1555 struct btrfs_block_group_cache *block_group)
1556 {
1557 if (bytenr >= block_group->key.objectid &&
1558 bytenr < block_group->key.objectid + block_group->key.offset)
1559 return 1;
1560 return 0;
1561 }
1562
1563 /*
1564 * get new location of data
1565 */
1566 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1567 u64 bytenr, u64 num_bytes)
1568 {
1569 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1570 struct btrfs_path *path;
1571 struct btrfs_file_extent_item *fi;
1572 struct extent_buffer *leaf;
1573 int ret;
1574
1575 path = btrfs_alloc_path();
1576 if (!path)
1577 return -ENOMEM;
1578
1579 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1580 ret = btrfs_lookup_file_extent(NULL, root, path,
1581 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1582 if (ret < 0)
1583 goto out;
1584 if (ret > 0) {
1585 ret = -ENOENT;
1586 goto out;
1587 }
1588
1589 leaf = path->nodes[0];
1590 fi = btrfs_item_ptr(leaf, path->slots[0],
1591 struct btrfs_file_extent_item);
1592
1593 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1594 btrfs_file_extent_compression(leaf, fi) ||
1595 btrfs_file_extent_encryption(leaf, fi) ||
1596 btrfs_file_extent_other_encoding(leaf, fi));
1597
1598 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1599 ret = -EINVAL;
1600 goto out;
1601 }
1602
1603 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1604 ret = 0;
1605 out:
1606 btrfs_free_path(path);
1607 return ret;
1608 }
1609
1610 /*
1611 * update file extent items in the tree leaf to point to
1612 * the new locations.
1613 */
1614 static noinline_for_stack
1615 int replace_file_extents(struct btrfs_trans_handle *trans,
1616 struct reloc_control *rc,
1617 struct btrfs_root *root,
1618 struct extent_buffer *leaf)
1619 {
1620 struct btrfs_fs_info *fs_info = root->fs_info;
1621 struct btrfs_key key;
1622 struct btrfs_file_extent_item *fi;
1623 struct inode *inode = NULL;
1624 u64 parent;
1625 u64 bytenr;
1626 u64 new_bytenr = 0;
1627 u64 num_bytes;
1628 u64 end;
1629 u32 nritems;
1630 u32 i;
1631 int ret = 0;
1632 int first = 1;
1633 int dirty = 0;
1634
1635 if (rc->stage != UPDATE_DATA_PTRS)
1636 return 0;
1637
1638 /* reloc trees always use full backref */
1639 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1640 parent = leaf->start;
1641 else
1642 parent = 0;
1643
1644 nritems = btrfs_header_nritems(leaf);
1645 for (i = 0; i < nritems; i++) {
1646 struct btrfs_ref ref = { 0 };
1647
1648 cond_resched();
1649 btrfs_item_key_to_cpu(leaf, &key, i);
1650 if (key.type != BTRFS_EXTENT_DATA_KEY)
1651 continue;
1652 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1653 if (btrfs_file_extent_type(leaf, fi) ==
1654 BTRFS_FILE_EXTENT_INLINE)
1655 continue;
1656 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1657 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1658 if (bytenr == 0)
1659 continue;
1660 if (!in_block_group(bytenr, rc->block_group))
1661 continue;
1662
1663 /*
1664 * if we are modifying block in fs tree, wait for readpage
1665 * to complete and drop the extent cache
1666 */
1667 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1668 if (first) {
1669 inode = find_next_inode(root, key.objectid);
1670 first = 0;
1671 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1672 btrfs_add_delayed_iput(inode);
1673 inode = find_next_inode(root, key.objectid);
1674 }
1675 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1676 end = key.offset +
1677 btrfs_file_extent_num_bytes(leaf, fi);
1678 WARN_ON(!IS_ALIGNED(key.offset,
1679 fs_info->sectorsize));
1680 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1681 end--;
1682 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1683 key.offset, end);
1684 if (!ret)
1685 continue;
1686
1687 btrfs_drop_extent_cache(BTRFS_I(inode),
1688 key.offset, end, 1);
1689 unlock_extent(&BTRFS_I(inode)->io_tree,
1690 key.offset, end);
1691 }
1692 }
1693
1694 ret = get_new_location(rc->data_inode, &new_bytenr,
1695 bytenr, num_bytes);
1696 if (ret) {
1697 /*
1698 * Don't have to abort since we've not changed anything
1699 * in the file extent yet.
1700 */
1701 break;
1702 }
1703
1704 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1705 dirty = 1;
1706
1707 key.offset -= btrfs_file_extent_offset(leaf, fi);
1708 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1709 num_bytes, parent);
1710 ref.real_root = root->root_key.objectid;
1711 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1712 key.objectid, key.offset);
1713 ret = btrfs_inc_extent_ref(trans, &ref);
1714 if (ret) {
1715 btrfs_abort_transaction(trans, ret);
1716 break;
1717 }
1718
1719 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1720 num_bytes, parent);
1721 ref.real_root = root->root_key.objectid;
1722 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1723 key.objectid, key.offset);
1724 ret = btrfs_free_extent(trans, &ref);
1725 if (ret) {
1726 btrfs_abort_transaction(trans, ret);
1727 break;
1728 }
1729 }
1730 if (dirty)
1731 btrfs_mark_buffer_dirty(leaf);
1732 if (inode)
1733 btrfs_add_delayed_iput(inode);
1734 return ret;
1735 }
1736
1737 static noinline_for_stack
1738 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1739 struct btrfs_path *path, int level)
1740 {
1741 struct btrfs_disk_key key1;
1742 struct btrfs_disk_key key2;
1743 btrfs_node_key(eb, &key1, slot);
1744 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1745 return memcmp(&key1, &key2, sizeof(key1));
1746 }
1747
1748 /*
1749 * try to replace tree blocks in fs tree with the new blocks
1750 * in reloc tree. tree blocks haven't been modified since the
1751 * reloc tree was create can be replaced.
1752 *
1753 * if a block was replaced, level of the block + 1 is returned.
1754 * if no block got replaced, 0 is returned. if there are other
1755 * errors, a negative error number is returned.
1756 */
1757 static noinline_for_stack
1758 int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1759 struct btrfs_root *dest, struct btrfs_root *src,
1760 struct btrfs_path *path, struct btrfs_key *next_key,
1761 int lowest_level, int max_level)
1762 {
1763 struct btrfs_fs_info *fs_info = dest->fs_info;
1764 struct extent_buffer *eb;
1765 struct extent_buffer *parent;
1766 struct btrfs_ref ref = { 0 };
1767 struct btrfs_key key;
1768 u64 old_bytenr;
1769 u64 new_bytenr;
1770 u64 old_ptr_gen;
1771 u64 new_ptr_gen;
1772 u64 last_snapshot;
1773 u32 blocksize;
1774 int cow = 0;
1775 int level;
1776 int ret;
1777 int slot;
1778
1779 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1780 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1781
1782 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1783 again:
1784 slot = path->slots[lowest_level];
1785 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1786
1787 eb = btrfs_lock_root_node(dest);
1788 btrfs_set_lock_blocking_write(eb);
1789 level = btrfs_header_level(eb);
1790
1791 if (level < lowest_level) {
1792 btrfs_tree_unlock(eb);
1793 free_extent_buffer(eb);
1794 return 0;
1795 }
1796
1797 if (cow) {
1798 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1799 BUG_ON(ret);
1800 }
1801 btrfs_set_lock_blocking_write(eb);
1802
1803 if (next_key) {
1804 next_key->objectid = (u64)-1;
1805 next_key->type = (u8)-1;
1806 next_key->offset = (u64)-1;
1807 }
1808
1809 parent = eb;
1810 while (1) {
1811 struct btrfs_key first_key;
1812
1813 level = btrfs_header_level(parent);
1814 BUG_ON(level < lowest_level);
1815
1816 ret = btrfs_bin_search(parent, &key, level, &slot);
1817 if (ret < 0)
1818 break;
1819 if (ret && slot > 0)
1820 slot--;
1821
1822 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1823 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1824
1825 old_bytenr = btrfs_node_blockptr(parent, slot);
1826 blocksize = fs_info->nodesize;
1827 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1828 btrfs_node_key_to_cpu(parent, &first_key, slot);
1829
1830 if (level <= max_level) {
1831 eb = path->nodes[level];
1832 new_bytenr = btrfs_node_blockptr(eb,
1833 path->slots[level]);
1834 new_ptr_gen = btrfs_node_ptr_generation(eb,
1835 path->slots[level]);
1836 } else {
1837 new_bytenr = 0;
1838 new_ptr_gen = 0;
1839 }
1840
1841 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1842 ret = level;
1843 break;
1844 }
1845
1846 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1847 memcmp_node_keys(parent, slot, path, level)) {
1848 if (level <= lowest_level) {
1849 ret = 0;
1850 break;
1851 }
1852
1853 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1854 level - 1, &first_key);
1855 if (IS_ERR(eb)) {
1856 ret = PTR_ERR(eb);
1857 break;
1858 } else if (!extent_buffer_uptodate(eb)) {
1859 ret = -EIO;
1860 free_extent_buffer(eb);
1861 break;
1862 }
1863 btrfs_tree_lock(eb);
1864 if (cow) {
1865 ret = btrfs_cow_block(trans, dest, eb, parent,
1866 slot, &eb);
1867 BUG_ON(ret);
1868 }
1869 btrfs_set_lock_blocking_write(eb);
1870
1871 btrfs_tree_unlock(parent);
1872 free_extent_buffer(parent);
1873
1874 parent = eb;
1875 continue;
1876 }
1877
1878 if (!cow) {
1879 btrfs_tree_unlock(parent);
1880 free_extent_buffer(parent);
1881 cow = 1;
1882 goto again;
1883 }
1884
1885 btrfs_node_key_to_cpu(path->nodes[level], &key,
1886 path->slots[level]);
1887 btrfs_release_path(path);
1888
1889 path->lowest_level = level;
1890 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1891 path->lowest_level = 0;
1892 BUG_ON(ret);
1893
1894 /*
1895 * Info qgroup to trace both subtrees.
1896 *
1897 * We must trace both trees.
1898 * 1) Tree reloc subtree
1899 * If not traced, we will leak data numbers
1900 * 2) Fs subtree
1901 * If not traced, we will double count old data
1902 *
1903 * We don't scan the subtree right now, but only record
1904 * the swapped tree blocks.
1905 * The real subtree rescan is delayed until we have new
1906 * CoW on the subtree root node before transaction commit.
1907 */
1908 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1909 rc->block_group, parent, slot,
1910 path->nodes[level], path->slots[level],
1911 last_snapshot);
1912 if (ret < 0)
1913 break;
1914 /*
1915 * swap blocks in fs tree and reloc tree.
1916 */
1917 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1918 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1919 btrfs_mark_buffer_dirty(parent);
1920
1921 btrfs_set_node_blockptr(path->nodes[level],
1922 path->slots[level], old_bytenr);
1923 btrfs_set_node_ptr_generation(path->nodes[level],
1924 path->slots[level], old_ptr_gen);
1925 btrfs_mark_buffer_dirty(path->nodes[level]);
1926
1927 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
1928 blocksize, path->nodes[level]->start);
1929 ref.skip_qgroup = true;
1930 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1931 ret = btrfs_inc_extent_ref(trans, &ref);
1932 BUG_ON(ret);
1933 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1934 blocksize, 0);
1935 ref.skip_qgroup = true;
1936 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1937 ret = btrfs_inc_extent_ref(trans, &ref);
1938 BUG_ON(ret);
1939
1940 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
1941 blocksize, path->nodes[level]->start);
1942 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1943 ref.skip_qgroup = true;
1944 ret = btrfs_free_extent(trans, &ref);
1945 BUG_ON(ret);
1946
1947 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1948 blocksize, 0);
1949 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1950 ref.skip_qgroup = true;
1951 ret = btrfs_free_extent(trans, &ref);
1952 BUG_ON(ret);
1953
1954 btrfs_unlock_up_safe(path, 0);
1955
1956 ret = level;
1957 break;
1958 }
1959 btrfs_tree_unlock(parent);
1960 free_extent_buffer(parent);
1961 return ret;
1962 }
1963
1964 /*
1965 * helper to find next relocated block in reloc tree
1966 */
1967 static noinline_for_stack
1968 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1969 int *level)
1970 {
1971 struct extent_buffer *eb;
1972 int i;
1973 u64 last_snapshot;
1974 u32 nritems;
1975
1976 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1977
1978 for (i = 0; i < *level; i++) {
1979 free_extent_buffer(path->nodes[i]);
1980 path->nodes[i] = NULL;
1981 }
1982
1983 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1984 eb = path->nodes[i];
1985 nritems = btrfs_header_nritems(eb);
1986 while (path->slots[i] + 1 < nritems) {
1987 path->slots[i]++;
1988 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1989 last_snapshot)
1990 continue;
1991
1992 *level = i;
1993 return 0;
1994 }
1995 free_extent_buffer(path->nodes[i]);
1996 path->nodes[i] = NULL;
1997 }
1998 return 1;
1999 }
2000
2001 /*
2002 * walk down reloc tree to find relocated block of lowest level
2003 */
2004 static noinline_for_stack
2005 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2006 int *level)
2007 {
2008 struct btrfs_fs_info *fs_info = root->fs_info;
2009 struct extent_buffer *eb = NULL;
2010 int i;
2011 u64 bytenr;
2012 u64 ptr_gen = 0;
2013 u64 last_snapshot;
2014 u32 nritems;
2015
2016 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2017
2018 for (i = *level; i > 0; i--) {
2019 struct btrfs_key first_key;
2020
2021 eb = path->nodes[i];
2022 nritems = btrfs_header_nritems(eb);
2023 while (path->slots[i] < nritems) {
2024 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2025 if (ptr_gen > last_snapshot)
2026 break;
2027 path->slots[i]++;
2028 }
2029 if (path->slots[i] >= nritems) {
2030 if (i == *level)
2031 break;
2032 *level = i + 1;
2033 return 0;
2034 }
2035 if (i == 1) {
2036 *level = i;
2037 return 0;
2038 }
2039
2040 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2041 btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
2042 eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
2043 &first_key);
2044 if (IS_ERR(eb)) {
2045 return PTR_ERR(eb);
2046 } else if (!extent_buffer_uptodate(eb)) {
2047 free_extent_buffer(eb);
2048 return -EIO;
2049 }
2050 BUG_ON(btrfs_header_level(eb) != i - 1);
2051 path->nodes[i - 1] = eb;
2052 path->slots[i - 1] = 0;
2053 }
2054 return 1;
2055 }
2056
2057 /*
2058 * invalidate extent cache for file extents whose key in range of
2059 * [min_key, max_key)
2060 */
2061 static int invalidate_extent_cache(struct btrfs_root *root,
2062 struct btrfs_key *min_key,
2063 struct btrfs_key *max_key)
2064 {
2065 struct btrfs_fs_info *fs_info = root->fs_info;
2066 struct inode *inode = NULL;
2067 u64 objectid;
2068 u64 start, end;
2069 u64 ino;
2070
2071 objectid = min_key->objectid;
2072 while (1) {
2073 cond_resched();
2074 iput(inode);
2075
2076 if (objectid > max_key->objectid)
2077 break;
2078
2079 inode = find_next_inode(root, objectid);
2080 if (!inode)
2081 break;
2082 ino = btrfs_ino(BTRFS_I(inode));
2083
2084 if (ino > max_key->objectid) {
2085 iput(inode);
2086 break;
2087 }
2088
2089 objectid = ino + 1;
2090 if (!S_ISREG(inode->i_mode))
2091 continue;
2092
2093 if (unlikely(min_key->objectid == ino)) {
2094 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2095 continue;
2096 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2097 start = 0;
2098 else {
2099 start = min_key->offset;
2100 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2101 }
2102 } else {
2103 start = 0;
2104 }
2105
2106 if (unlikely(max_key->objectid == ino)) {
2107 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2108 continue;
2109 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2110 end = (u64)-1;
2111 } else {
2112 if (max_key->offset == 0)
2113 continue;
2114 end = max_key->offset;
2115 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2116 end--;
2117 }
2118 } else {
2119 end = (u64)-1;
2120 }
2121
2122 /* the lock_extent waits for readpage to complete */
2123 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2124 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2125 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2126 }
2127 return 0;
2128 }
2129
2130 static int find_next_key(struct btrfs_path *path, int level,
2131 struct btrfs_key *key)
2132
2133 {
2134 while (level < BTRFS_MAX_LEVEL) {
2135 if (!path->nodes[level])
2136 break;
2137 if (path->slots[level] + 1 <
2138 btrfs_header_nritems(path->nodes[level])) {
2139 btrfs_node_key_to_cpu(path->nodes[level], key,
2140 path->slots[level] + 1);
2141 return 0;
2142 }
2143 level++;
2144 }
2145 return 1;
2146 }
2147
2148 /*
2149 * Insert current subvolume into reloc_control::dirty_subvol_roots
2150 */
2151 static void insert_dirty_subvol(struct btrfs_trans_handle *trans,
2152 struct reloc_control *rc,
2153 struct btrfs_root *root)
2154 {
2155 struct btrfs_root *reloc_root = root->reloc_root;
2156 struct btrfs_root_item *reloc_root_item;
2157
2158 /* @root must be a subvolume tree root with a valid reloc tree */
2159 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
2160 ASSERT(reloc_root);
2161
2162 reloc_root_item = &reloc_root->root_item;
2163 memset(&reloc_root_item->drop_progress, 0,
2164 sizeof(reloc_root_item->drop_progress));
2165 reloc_root_item->drop_level = 0;
2166 btrfs_set_root_refs(reloc_root_item, 0);
2167 btrfs_update_reloc_root(trans, root);
2168
2169 if (list_empty(&root->reloc_dirty_list)) {
2170 btrfs_grab_fs_root(root);
2171 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
2172 }
2173 }
2174
2175 static int clean_dirty_subvols(struct reloc_control *rc)
2176 {
2177 struct btrfs_root *root;
2178 struct btrfs_root *next;
2179 int ret = 0;
2180 int ret2;
2181
2182 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
2183 reloc_dirty_list) {
2184 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
2185 /* Merged subvolume, cleanup its reloc root */
2186 struct btrfs_root *reloc_root = root->reloc_root;
2187
2188 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
2189 list_del_init(&root->reloc_dirty_list);
2190 root->reloc_root = NULL;
2191 if (reloc_root) {
2192
2193 ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1);
2194 if (ret2 < 0 && !ret)
2195 ret = ret2;
2196 }
2197 btrfs_put_fs_root(root);
2198 } else {
2199 /* Orphan reloc tree, just clean it up */
2200 ret2 = btrfs_drop_snapshot(root, NULL, 0, 1);
2201 if (ret2 < 0 && !ret)
2202 ret = ret2;
2203 }
2204 }
2205 return ret;
2206 }
2207
2208 /*
2209 * merge the relocated tree blocks in reloc tree with corresponding
2210 * fs tree.
2211 */
2212 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2213 struct btrfs_root *root)
2214 {
2215 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2216 struct btrfs_key key;
2217 struct btrfs_key next_key;
2218 struct btrfs_trans_handle *trans = NULL;
2219 struct btrfs_root *reloc_root;
2220 struct btrfs_root_item *root_item;
2221 struct btrfs_path *path;
2222 struct extent_buffer *leaf;
2223 int level;
2224 int max_level;
2225 int replaced = 0;
2226 int ret;
2227 int err = 0;
2228 u32 min_reserved;
2229
2230 path = btrfs_alloc_path();
2231 if (!path)
2232 return -ENOMEM;
2233 path->reada = READA_FORWARD;
2234
2235 reloc_root = root->reloc_root;
2236 root_item = &reloc_root->root_item;
2237
2238 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2239 level = btrfs_root_level(root_item);
2240 extent_buffer_get(reloc_root->node);
2241 path->nodes[level] = reloc_root->node;
2242 path->slots[level] = 0;
2243 } else {
2244 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2245
2246 level = root_item->drop_level;
2247 BUG_ON(level == 0);
2248 path->lowest_level = level;
2249 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2250 path->lowest_level = 0;
2251 if (ret < 0) {
2252 btrfs_free_path(path);
2253 return ret;
2254 }
2255
2256 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2257 path->slots[level]);
2258 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2259
2260 btrfs_unlock_up_safe(path, 0);
2261 }
2262
2263 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2264 memset(&next_key, 0, sizeof(next_key));
2265
2266 while (1) {
2267 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2268 BTRFS_RESERVE_FLUSH_ALL);
2269 if (ret) {
2270 err = ret;
2271 goto out;
2272 }
2273 trans = btrfs_start_transaction(root, 0);
2274 if (IS_ERR(trans)) {
2275 err = PTR_ERR(trans);
2276 trans = NULL;
2277 goto out;
2278 }
2279 trans->block_rsv = rc->block_rsv;
2280
2281 replaced = 0;
2282 max_level = level;
2283
2284 ret = walk_down_reloc_tree(reloc_root, path, &level);
2285 if (ret < 0) {
2286 err = ret;
2287 goto out;
2288 }
2289 if (ret > 0)
2290 break;
2291
2292 if (!find_next_key(path, level, &key) &&
2293 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2294 ret = 0;
2295 } else {
2296 ret = replace_path(trans, rc, root, reloc_root, path,
2297 &next_key, level, max_level);
2298 }
2299 if (ret < 0) {
2300 err = ret;
2301 goto out;
2302 }
2303
2304 if (ret > 0) {
2305 level = ret;
2306 btrfs_node_key_to_cpu(path->nodes[level], &key,
2307 path->slots[level]);
2308 replaced = 1;
2309 }
2310
2311 ret = walk_up_reloc_tree(reloc_root, path, &level);
2312 if (ret > 0)
2313 break;
2314
2315 BUG_ON(level == 0);
2316 /*
2317 * save the merging progress in the drop_progress.
2318 * this is OK since root refs == 1 in this case.
2319 */
2320 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2321 path->slots[level]);
2322 root_item->drop_level = level;
2323
2324 btrfs_end_transaction_throttle(trans);
2325 trans = NULL;
2326
2327 btrfs_btree_balance_dirty(fs_info);
2328
2329 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2330 invalidate_extent_cache(root, &key, &next_key);
2331 }
2332
2333 /*
2334 * handle the case only one block in the fs tree need to be
2335 * relocated and the block is tree root.
2336 */
2337 leaf = btrfs_lock_root_node(root);
2338 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2339 btrfs_tree_unlock(leaf);
2340 free_extent_buffer(leaf);
2341 if (ret < 0)
2342 err = ret;
2343 out:
2344 btrfs_free_path(path);
2345
2346 if (err == 0)
2347 insert_dirty_subvol(trans, rc, root);
2348
2349 if (trans)
2350 btrfs_end_transaction_throttle(trans);
2351
2352 btrfs_btree_balance_dirty(fs_info);
2353
2354 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2355 invalidate_extent_cache(root, &key, &next_key);
2356
2357 return err;
2358 }
2359
2360 static noinline_for_stack
2361 int prepare_to_merge(struct reloc_control *rc, int err)
2362 {
2363 struct btrfs_root *root = rc->extent_root;
2364 struct btrfs_fs_info *fs_info = root->fs_info;
2365 struct btrfs_root *reloc_root;
2366 struct btrfs_trans_handle *trans;
2367 LIST_HEAD(reloc_roots);
2368 u64 num_bytes = 0;
2369 int ret;
2370
2371 mutex_lock(&fs_info->reloc_mutex);
2372 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2373 rc->merging_rsv_size += rc->nodes_relocated * 2;
2374 mutex_unlock(&fs_info->reloc_mutex);
2375
2376 again:
2377 if (!err) {
2378 num_bytes = rc->merging_rsv_size;
2379 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2380 BTRFS_RESERVE_FLUSH_ALL);
2381 if (ret)
2382 err = ret;
2383 }
2384
2385 trans = btrfs_join_transaction(rc->extent_root);
2386 if (IS_ERR(trans)) {
2387 if (!err)
2388 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2389 num_bytes);
2390 return PTR_ERR(trans);
2391 }
2392
2393 if (!err) {
2394 if (num_bytes != rc->merging_rsv_size) {
2395 btrfs_end_transaction(trans);
2396 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2397 num_bytes);
2398 goto again;
2399 }
2400 }
2401
2402 rc->merge_reloc_tree = 1;
2403
2404 while (!list_empty(&rc->reloc_roots)) {
2405 reloc_root = list_entry(rc->reloc_roots.next,
2406 struct btrfs_root, root_list);
2407 list_del_init(&reloc_root->root_list);
2408
2409 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2410 BUG_ON(IS_ERR(root));
2411 BUG_ON(root->reloc_root != reloc_root);
2412
2413 /*
2414 * set reference count to 1, so btrfs_recover_relocation
2415 * knows it should resumes merging
2416 */
2417 if (!err)
2418 btrfs_set_root_refs(&reloc_root->root_item, 1);
2419 btrfs_update_reloc_root(trans, root);
2420
2421 list_add(&reloc_root->root_list, &reloc_roots);
2422 }
2423
2424 list_splice(&reloc_roots, &rc->reloc_roots);
2425
2426 if (!err)
2427 btrfs_commit_transaction(trans);
2428 else
2429 btrfs_end_transaction(trans);
2430 return err;
2431 }
2432
2433 static noinline_for_stack
2434 void free_reloc_roots(struct list_head *list)
2435 {
2436 struct btrfs_root *reloc_root;
2437
2438 while (!list_empty(list)) {
2439 reloc_root = list_entry(list->next, struct btrfs_root,
2440 root_list);
2441 __del_reloc_root(reloc_root);
2442 free_extent_buffer(reloc_root->node);
2443 free_extent_buffer(reloc_root->commit_root);
2444 reloc_root->node = NULL;
2445 reloc_root->commit_root = NULL;
2446 }
2447 }
2448
2449 static noinline_for_stack
2450 void merge_reloc_roots(struct reloc_control *rc)
2451 {
2452 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2453 struct btrfs_root *root;
2454 struct btrfs_root *reloc_root;
2455 LIST_HEAD(reloc_roots);
2456 int found = 0;
2457 int ret = 0;
2458 again:
2459 root = rc->extent_root;
2460
2461 /*
2462 * this serializes us with btrfs_record_root_in_transaction,
2463 * we have to make sure nobody is in the middle of
2464 * adding their roots to the list while we are
2465 * doing this splice
2466 */
2467 mutex_lock(&fs_info->reloc_mutex);
2468 list_splice_init(&rc->reloc_roots, &reloc_roots);
2469 mutex_unlock(&fs_info->reloc_mutex);
2470
2471 while (!list_empty(&reloc_roots)) {
2472 found = 1;
2473 reloc_root = list_entry(reloc_roots.next,
2474 struct btrfs_root, root_list);
2475
2476 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2477 root = read_fs_root(fs_info,
2478 reloc_root->root_key.offset);
2479 BUG_ON(IS_ERR(root));
2480 BUG_ON(root->reloc_root != reloc_root);
2481
2482 ret = merge_reloc_root(rc, root);
2483 if (ret) {
2484 if (list_empty(&reloc_root->root_list))
2485 list_add_tail(&reloc_root->root_list,
2486 &reloc_roots);
2487 goto out;
2488 }
2489 } else {
2490 list_del_init(&reloc_root->root_list);
2491 /* Don't forget to queue this reloc root for cleanup */
2492 list_add_tail(&reloc_root->reloc_dirty_list,
2493 &rc->dirty_subvol_roots);
2494 }
2495 }
2496
2497 if (found) {
2498 found = 0;
2499 goto again;
2500 }
2501 out:
2502 if (ret) {
2503 btrfs_handle_fs_error(fs_info, ret, NULL);
2504 if (!list_empty(&reloc_roots))
2505 free_reloc_roots(&reloc_roots);
2506
2507 /* new reloc root may be added */
2508 mutex_lock(&fs_info->reloc_mutex);
2509 list_splice_init(&rc->reloc_roots, &reloc_roots);
2510 mutex_unlock(&fs_info->reloc_mutex);
2511 if (!list_empty(&reloc_roots))
2512 free_reloc_roots(&reloc_roots);
2513 }
2514
2515 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2516 }
2517
2518 static void free_block_list(struct rb_root *blocks)
2519 {
2520 struct tree_block *block;
2521 struct rb_node *rb_node;
2522 while ((rb_node = rb_first(blocks))) {
2523 block = rb_entry(rb_node, struct tree_block, rb_node);
2524 rb_erase(rb_node, blocks);
2525 kfree(block);
2526 }
2527 }
2528
2529 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2530 struct btrfs_root *reloc_root)
2531 {
2532 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2533 struct btrfs_root *root;
2534
2535 if (reloc_root->last_trans == trans->transid)
2536 return 0;
2537
2538 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2539 BUG_ON(IS_ERR(root));
2540 BUG_ON(root->reloc_root != reloc_root);
2541
2542 return btrfs_record_root_in_trans(trans, root);
2543 }
2544
2545 static noinline_for_stack
2546 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2547 struct reloc_control *rc,
2548 struct backref_node *node,
2549 struct backref_edge *edges[])
2550 {
2551 struct backref_node *next;
2552 struct btrfs_root *root;
2553 int index = 0;
2554
2555 next = node;
2556 while (1) {
2557 cond_resched();
2558 next = walk_up_backref(next, edges, &index);
2559 root = next->root;
2560 BUG_ON(!root);
2561 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2562
2563 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2564 record_reloc_root_in_trans(trans, root);
2565 break;
2566 }
2567
2568 btrfs_record_root_in_trans(trans, root);
2569 root = root->reloc_root;
2570
2571 if (next->new_bytenr != root->node->start) {
2572 BUG_ON(next->new_bytenr);
2573 BUG_ON(!list_empty(&next->list));
2574 next->new_bytenr = root->node->start;
2575 next->root = root;
2576 list_add_tail(&next->list,
2577 &rc->backref_cache.changed);
2578 __mark_block_processed(rc, next);
2579 break;
2580 }
2581
2582 WARN_ON(1);
2583 root = NULL;
2584 next = walk_down_backref(edges, &index);
2585 if (!next || next->level <= node->level)
2586 break;
2587 }
2588 if (!root)
2589 return NULL;
2590
2591 next = node;
2592 /* setup backref node path for btrfs_reloc_cow_block */
2593 while (1) {
2594 rc->backref_cache.path[next->level] = next;
2595 if (--index < 0)
2596 break;
2597 next = edges[index]->node[UPPER];
2598 }
2599 return root;
2600 }
2601
2602 /*
2603 * select a tree root for relocation. return NULL if the block
2604 * is reference counted. we should use do_relocation() in this
2605 * case. return a tree root pointer if the block isn't reference
2606 * counted. return -ENOENT if the block is root of reloc tree.
2607 */
2608 static noinline_for_stack
2609 struct btrfs_root *select_one_root(struct backref_node *node)
2610 {
2611 struct backref_node *next;
2612 struct btrfs_root *root;
2613 struct btrfs_root *fs_root = NULL;
2614 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2615 int index = 0;
2616
2617 next = node;
2618 while (1) {
2619 cond_resched();
2620 next = walk_up_backref(next, edges, &index);
2621 root = next->root;
2622 BUG_ON(!root);
2623
2624 /* no other choice for non-references counted tree */
2625 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2626 return root;
2627
2628 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2629 fs_root = root;
2630
2631 if (next != node)
2632 return NULL;
2633
2634 next = walk_down_backref(edges, &index);
2635 if (!next || next->level <= node->level)
2636 break;
2637 }
2638
2639 if (!fs_root)
2640 return ERR_PTR(-ENOENT);
2641 return fs_root;
2642 }
2643
2644 static noinline_for_stack
2645 u64 calcu_metadata_size(struct reloc_control *rc,
2646 struct backref_node *node, int reserve)
2647 {
2648 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2649 struct backref_node *next = node;
2650 struct backref_edge *edge;
2651 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2652 u64 num_bytes = 0;
2653 int index = 0;
2654
2655 BUG_ON(reserve && node->processed);
2656
2657 while (next) {
2658 cond_resched();
2659 while (1) {
2660 if (next->processed && (reserve || next != node))
2661 break;
2662
2663 num_bytes += fs_info->nodesize;
2664
2665 if (list_empty(&next->upper))
2666 break;
2667
2668 edge = list_entry(next->upper.next,
2669 struct backref_edge, list[LOWER]);
2670 edges[index++] = edge;
2671 next = edge->node[UPPER];
2672 }
2673 next = walk_down_backref(edges, &index);
2674 }
2675 return num_bytes;
2676 }
2677
2678 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2679 struct reloc_control *rc,
2680 struct backref_node *node)
2681 {
2682 struct btrfs_root *root = rc->extent_root;
2683 struct btrfs_fs_info *fs_info = root->fs_info;
2684 u64 num_bytes;
2685 int ret;
2686 u64 tmp;
2687
2688 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2689
2690 trans->block_rsv = rc->block_rsv;
2691 rc->reserved_bytes += num_bytes;
2692
2693 /*
2694 * We are under a transaction here so we can only do limited flushing.
2695 * If we get an enospc just kick back -EAGAIN so we know to drop the
2696 * transaction and try to refill when we can flush all the things.
2697 */
2698 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2699 BTRFS_RESERVE_FLUSH_LIMIT);
2700 if (ret) {
2701 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2702 while (tmp <= rc->reserved_bytes)
2703 tmp <<= 1;
2704 /*
2705 * only one thread can access block_rsv at this point,
2706 * so we don't need hold lock to protect block_rsv.
2707 * we expand more reservation size here to allow enough
2708 * space for relocation and we will return earlier in
2709 * enospc case.
2710 */
2711 rc->block_rsv->size = tmp + fs_info->nodesize *
2712 RELOCATION_RESERVED_NODES;
2713 return -EAGAIN;
2714 }
2715
2716 return 0;
2717 }
2718
2719 /*
2720 * relocate a block tree, and then update pointers in upper level
2721 * blocks that reference the block to point to the new location.
2722 *
2723 * if called by link_to_upper, the block has already been relocated.
2724 * in that case this function just updates pointers.
2725 */
2726 static int do_relocation(struct btrfs_trans_handle *trans,
2727 struct reloc_control *rc,
2728 struct backref_node *node,
2729 struct btrfs_key *key,
2730 struct btrfs_path *path, int lowest)
2731 {
2732 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2733 struct backref_node *upper;
2734 struct backref_edge *edge;
2735 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2736 struct btrfs_root *root;
2737 struct extent_buffer *eb;
2738 u32 blocksize;
2739 u64 bytenr;
2740 u64 generation;
2741 int slot;
2742 int ret;
2743 int err = 0;
2744
2745 BUG_ON(lowest && node->eb);
2746
2747 path->lowest_level = node->level + 1;
2748 rc->backref_cache.path[node->level] = node;
2749 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2750 struct btrfs_key first_key;
2751 struct btrfs_ref ref = { 0 };
2752
2753 cond_resched();
2754
2755 upper = edge->node[UPPER];
2756 root = select_reloc_root(trans, rc, upper, edges);
2757 BUG_ON(!root);
2758
2759 if (upper->eb && !upper->locked) {
2760 if (!lowest) {
2761 ret = btrfs_bin_search(upper->eb, key,
2762 upper->level, &slot);
2763 if (ret < 0) {
2764 err = ret;
2765 goto next;
2766 }
2767 BUG_ON(ret);
2768 bytenr = btrfs_node_blockptr(upper->eb, slot);
2769 if (node->eb->start == bytenr)
2770 goto next;
2771 }
2772 drop_node_buffer(upper);
2773 }
2774
2775 if (!upper->eb) {
2776 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2777 if (ret) {
2778 if (ret < 0)
2779 err = ret;
2780 else
2781 err = -ENOENT;
2782
2783 btrfs_release_path(path);
2784 break;
2785 }
2786
2787 if (!upper->eb) {
2788 upper->eb = path->nodes[upper->level];
2789 path->nodes[upper->level] = NULL;
2790 } else {
2791 BUG_ON(upper->eb != path->nodes[upper->level]);
2792 }
2793
2794 upper->locked = 1;
2795 path->locks[upper->level] = 0;
2796
2797 slot = path->slots[upper->level];
2798 btrfs_release_path(path);
2799 } else {
2800 ret = btrfs_bin_search(upper->eb, key, upper->level,
2801 &slot);
2802 if (ret < 0) {
2803 err = ret;
2804 goto next;
2805 }
2806 BUG_ON(ret);
2807 }
2808
2809 bytenr = btrfs_node_blockptr(upper->eb, slot);
2810 if (lowest) {
2811 if (bytenr != node->bytenr) {
2812 btrfs_err(root->fs_info,
2813 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2814 bytenr, node->bytenr, slot,
2815 upper->eb->start);
2816 err = -EIO;
2817 goto next;
2818 }
2819 } else {
2820 if (node->eb->start == bytenr)
2821 goto next;
2822 }
2823
2824 blocksize = root->fs_info->nodesize;
2825 generation = btrfs_node_ptr_generation(upper->eb, slot);
2826 btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
2827 eb = read_tree_block(fs_info, bytenr, generation,
2828 upper->level - 1, &first_key);
2829 if (IS_ERR(eb)) {
2830 err = PTR_ERR(eb);
2831 goto next;
2832 } else if (!extent_buffer_uptodate(eb)) {
2833 free_extent_buffer(eb);
2834 err = -EIO;
2835 goto next;
2836 }
2837 btrfs_tree_lock(eb);
2838 btrfs_set_lock_blocking_write(eb);
2839
2840 if (!node->eb) {
2841 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2842 slot, &eb);
2843 btrfs_tree_unlock(eb);
2844 free_extent_buffer(eb);
2845 if (ret < 0) {
2846 err = ret;
2847 goto next;
2848 }
2849 BUG_ON(node->eb != eb);
2850 } else {
2851 btrfs_set_node_blockptr(upper->eb, slot,
2852 node->eb->start);
2853 btrfs_set_node_ptr_generation(upper->eb, slot,
2854 trans->transid);
2855 btrfs_mark_buffer_dirty(upper->eb);
2856
2857 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2858 node->eb->start, blocksize,
2859 upper->eb->start);
2860 ref.real_root = root->root_key.objectid;
2861 btrfs_init_tree_ref(&ref, node->level,
2862 btrfs_header_owner(upper->eb));
2863 ret = btrfs_inc_extent_ref(trans, &ref);
2864 BUG_ON(ret);
2865
2866 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2867 BUG_ON(ret);
2868 }
2869 next:
2870 if (!upper->pending)
2871 drop_node_buffer(upper);
2872 else
2873 unlock_node_buffer(upper);
2874 if (err)
2875 break;
2876 }
2877
2878 if (!err && node->pending) {
2879 drop_node_buffer(node);
2880 list_move_tail(&node->list, &rc->backref_cache.changed);
2881 node->pending = 0;
2882 }
2883
2884 path->lowest_level = 0;
2885 BUG_ON(err == -ENOSPC);
2886 return err;
2887 }
2888
2889 static int link_to_upper(struct btrfs_trans_handle *trans,
2890 struct reloc_control *rc,
2891 struct backref_node *node,
2892 struct btrfs_path *path)
2893 {
2894 struct btrfs_key key;
2895
2896 btrfs_node_key_to_cpu(node->eb, &key, 0);
2897 return do_relocation(trans, rc, node, &key, path, 0);
2898 }
2899
2900 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2901 struct reloc_control *rc,
2902 struct btrfs_path *path, int err)
2903 {
2904 LIST_HEAD(list);
2905 struct backref_cache *cache = &rc->backref_cache;
2906 struct backref_node *node;
2907 int level;
2908 int ret;
2909
2910 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2911 while (!list_empty(&cache->pending[level])) {
2912 node = list_entry(cache->pending[level].next,
2913 struct backref_node, list);
2914 list_move_tail(&node->list, &list);
2915 BUG_ON(!node->pending);
2916
2917 if (!err) {
2918 ret = link_to_upper(trans, rc, node, path);
2919 if (ret < 0)
2920 err = ret;
2921 }
2922 }
2923 list_splice_init(&list, &cache->pending[level]);
2924 }
2925 return err;
2926 }
2927
2928 static void mark_block_processed(struct reloc_control *rc,
2929 u64 bytenr, u32 blocksize)
2930 {
2931 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2932 EXTENT_DIRTY);
2933 }
2934
2935 static void __mark_block_processed(struct reloc_control *rc,
2936 struct backref_node *node)
2937 {
2938 u32 blocksize;
2939 if (node->level == 0 ||
2940 in_block_group(node->bytenr, rc->block_group)) {
2941 blocksize = rc->extent_root->fs_info->nodesize;
2942 mark_block_processed(rc, node->bytenr, blocksize);
2943 }
2944 node->processed = 1;
2945 }
2946
2947 /*
2948 * mark a block and all blocks directly/indirectly reference the block
2949 * as processed.
2950 */
2951 static void update_processed_blocks(struct reloc_control *rc,
2952 struct backref_node *node)
2953 {
2954 struct backref_node *next = node;
2955 struct backref_edge *edge;
2956 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2957 int index = 0;
2958
2959 while (next) {
2960 cond_resched();
2961 while (1) {
2962 if (next->processed)
2963 break;
2964
2965 __mark_block_processed(rc, next);
2966
2967 if (list_empty(&next->upper))
2968 break;
2969
2970 edge = list_entry(next->upper.next,
2971 struct backref_edge, list[LOWER]);
2972 edges[index++] = edge;
2973 next = edge->node[UPPER];
2974 }
2975 next = walk_down_backref(edges, &index);
2976 }
2977 }
2978
2979 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2980 {
2981 u32 blocksize = rc->extent_root->fs_info->nodesize;
2982
2983 if (test_range_bit(&rc->processed_blocks, bytenr,
2984 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2985 return 1;
2986 return 0;
2987 }
2988
2989 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2990 struct tree_block *block)
2991 {
2992 struct extent_buffer *eb;
2993
2994 BUG_ON(block->key_ready);
2995 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
2996 block->level, NULL);
2997 if (IS_ERR(eb)) {
2998 return PTR_ERR(eb);
2999 } else if (!extent_buffer_uptodate(eb)) {
3000 free_extent_buffer(eb);
3001 return -EIO;
3002 }
3003 if (block->level == 0)
3004 btrfs_item_key_to_cpu(eb, &block->key, 0);
3005 else
3006 btrfs_node_key_to_cpu(eb, &block->key, 0);
3007 free_extent_buffer(eb);
3008 block->key_ready = 1;
3009 return 0;
3010 }
3011
3012 /*
3013 * helper function to relocate a tree block
3014 */
3015 static int relocate_tree_block(struct btrfs_trans_handle *trans,
3016 struct reloc_control *rc,
3017 struct backref_node *node,
3018 struct btrfs_key *key,
3019 struct btrfs_path *path)
3020 {
3021 struct btrfs_root *root;
3022 int ret = 0;
3023
3024 if (!node)
3025 return 0;
3026
3027 BUG_ON(node->processed);
3028 root = select_one_root(node);
3029 if (root == ERR_PTR(-ENOENT)) {
3030 update_processed_blocks(rc, node);
3031 goto out;
3032 }
3033
3034 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3035 ret = reserve_metadata_space(trans, rc, node);
3036 if (ret)
3037 goto out;
3038 }
3039
3040 if (root) {
3041 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3042 BUG_ON(node->new_bytenr);
3043 BUG_ON(!list_empty(&node->list));
3044 btrfs_record_root_in_trans(trans, root);
3045 root = root->reloc_root;
3046 node->new_bytenr = root->node->start;
3047 node->root = root;
3048 list_add_tail(&node->list, &rc->backref_cache.changed);
3049 } else {
3050 path->lowest_level = node->level;
3051 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3052 btrfs_release_path(path);
3053 if (ret > 0)
3054 ret = 0;
3055 }
3056 if (!ret)
3057 update_processed_blocks(rc, node);
3058 } else {
3059 ret = do_relocation(trans, rc, node, key, path, 1);
3060 }
3061 out:
3062 if (ret || node->level == 0 || node->cowonly)
3063 remove_backref_node(&rc->backref_cache, node);
3064 return ret;
3065 }
3066
3067 /*
3068 * relocate a list of blocks
3069 */
3070 static noinline_for_stack
3071 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3072 struct reloc_control *rc, struct rb_root *blocks)
3073 {
3074 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3075 struct backref_node *node;
3076 struct btrfs_path *path;
3077 struct tree_block *block;
3078 struct tree_block *next;
3079 int ret;
3080 int err = 0;
3081
3082 path = btrfs_alloc_path();
3083 if (!path) {
3084 err = -ENOMEM;
3085 goto out_free_blocks;
3086 }
3087
3088 /* Kick in readahead for tree blocks with missing keys */
3089 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3090 if (!block->key_ready)
3091 readahead_tree_block(fs_info, block->bytenr);
3092 }
3093
3094 /* Get first keys */
3095 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3096 if (!block->key_ready) {
3097 err = get_tree_block_key(fs_info, block);
3098 if (err)
3099 goto out_free_path;
3100 }
3101 }
3102
3103 /* Do tree relocation */
3104 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3105 node = build_backref_tree(rc, &block->key,
3106 block->level, block->bytenr);
3107 if (IS_ERR(node)) {
3108 err = PTR_ERR(node);
3109 goto out;
3110 }
3111
3112 ret = relocate_tree_block(trans, rc, node, &block->key,
3113 path);
3114 if (ret < 0) {
3115 if (ret != -EAGAIN || &block->rb_node == rb_first(blocks))
3116 err = ret;
3117 goto out;
3118 }
3119 }
3120 out:
3121 err = finish_pending_nodes(trans, rc, path, err);
3122
3123 out_free_path:
3124 btrfs_free_path(path);
3125 out_free_blocks:
3126 free_block_list(blocks);
3127 return err;
3128 }
3129
3130 static noinline_for_stack
3131 int prealloc_file_extent_cluster(struct inode *inode,
3132 struct file_extent_cluster *cluster)
3133 {
3134 u64 alloc_hint = 0;
3135 u64 start;
3136 u64 end;
3137 u64 offset = BTRFS_I(inode)->index_cnt;
3138 u64 num_bytes;
3139 int nr = 0;
3140 int ret = 0;
3141 u64 prealloc_start = cluster->start - offset;
3142 u64 prealloc_end = cluster->end - offset;
3143 u64 cur_offset;
3144 struct extent_changeset *data_reserved = NULL;
3145
3146 BUG_ON(cluster->start != cluster->boundary[0]);
3147 inode_lock(inode);
3148
3149 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3150 prealloc_end + 1 - prealloc_start);
3151 if (ret)
3152 goto out;
3153
3154 cur_offset = prealloc_start;
3155 while (nr < cluster->nr) {
3156 start = cluster->boundary[nr] - offset;
3157 if (nr + 1 < cluster->nr)
3158 end = cluster->boundary[nr + 1] - 1 - offset;
3159 else
3160 end = cluster->end - offset;
3161
3162 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3163 num_bytes = end + 1 - start;
3164 if (cur_offset < start)
3165 btrfs_free_reserved_data_space(inode, data_reserved,
3166 cur_offset, start - cur_offset);
3167 ret = btrfs_prealloc_file_range(inode, 0, start,
3168 num_bytes, num_bytes,
3169 end + 1, &alloc_hint);
3170 cur_offset = end + 1;
3171 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3172 if (ret)
3173 break;
3174 nr++;
3175 }
3176 if (cur_offset < prealloc_end)
3177 btrfs_free_reserved_data_space(inode, data_reserved,
3178 cur_offset, prealloc_end + 1 - cur_offset);
3179 out:
3180 inode_unlock(inode);
3181 extent_changeset_free(data_reserved);
3182 return ret;
3183 }
3184
3185 static noinline_for_stack
3186 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3187 u64 block_start)
3188 {
3189 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3190 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3191 struct extent_map *em;
3192 int ret = 0;
3193
3194 em = alloc_extent_map();
3195 if (!em)
3196 return -ENOMEM;
3197
3198 em->start = start;
3199 em->len = end + 1 - start;
3200 em->block_len = em->len;
3201 em->block_start = block_start;
3202 em->bdev = fs_info->fs_devices->latest_bdev;
3203 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3204
3205 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3206 while (1) {
3207 write_lock(&em_tree->lock);
3208 ret = add_extent_mapping(em_tree, em, 0);
3209 write_unlock(&em_tree->lock);
3210 if (ret != -EEXIST) {
3211 free_extent_map(em);
3212 break;
3213 }
3214 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3215 }
3216 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3217 return ret;
3218 }
3219
3220 static int relocate_file_extent_cluster(struct inode *inode,
3221 struct file_extent_cluster *cluster)
3222 {
3223 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3224 u64 page_start;
3225 u64 page_end;
3226 u64 offset = BTRFS_I(inode)->index_cnt;
3227 unsigned long index;
3228 unsigned long last_index;
3229 struct page *page;
3230 struct file_ra_state *ra;
3231 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3232 int nr = 0;
3233 int ret = 0;
3234
3235 if (!cluster->nr)
3236 return 0;
3237
3238 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3239 if (!ra)
3240 return -ENOMEM;
3241
3242 ret = prealloc_file_extent_cluster(inode, cluster);
3243 if (ret)
3244 goto out;
3245
3246 file_ra_state_init(ra, inode->i_mapping);
3247
3248 ret = setup_extent_mapping(inode, cluster->start - offset,
3249 cluster->end - offset, cluster->start);
3250 if (ret)
3251 goto out;
3252
3253 index = (cluster->start - offset) >> PAGE_SHIFT;
3254 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3255 while (index <= last_index) {
3256 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3257 PAGE_SIZE);
3258 if (ret)
3259 goto out;
3260
3261 page = find_lock_page(inode->i_mapping, index);
3262 if (!page) {
3263 page_cache_sync_readahead(inode->i_mapping,
3264 ra, NULL, index,
3265 last_index + 1 - index);
3266 page = find_or_create_page(inode->i_mapping, index,
3267 mask);
3268 if (!page) {
3269 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3270 PAGE_SIZE, true);
3271 ret = -ENOMEM;
3272 goto out;
3273 }
3274 }
3275
3276 if (PageReadahead(page)) {
3277 page_cache_async_readahead(inode->i_mapping,
3278 ra, NULL, page, index,
3279 last_index + 1 - index);
3280 }
3281
3282 if (!PageUptodate(page)) {
3283 btrfs_readpage(NULL, page);
3284 lock_page(page);
3285 if (!PageUptodate(page)) {
3286 unlock_page(page);
3287 put_page(page);
3288 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3289 PAGE_SIZE, true);
3290 btrfs_delalloc_release_extents(BTRFS_I(inode),
3291 PAGE_SIZE, true);
3292 ret = -EIO;
3293 goto out;
3294 }
3295 }
3296
3297 page_start = page_offset(page);
3298 page_end = page_start + PAGE_SIZE - 1;
3299
3300 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3301
3302 set_page_extent_mapped(page);
3303
3304 if (nr < cluster->nr &&
3305 page_start + offset == cluster->boundary[nr]) {
3306 set_extent_bits(&BTRFS_I(inode)->io_tree,
3307 page_start, page_end,
3308 EXTENT_BOUNDARY);
3309 nr++;
3310 }
3311
3312 ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
3313 NULL, 0);
3314 if (ret) {
3315 unlock_page(page);
3316 put_page(page);
3317 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3318 PAGE_SIZE, true);
3319 btrfs_delalloc_release_extents(BTRFS_I(inode),
3320 PAGE_SIZE, true);
3321
3322 clear_extent_bits(&BTRFS_I(inode)->io_tree,
3323 page_start, page_end,
3324 EXTENT_LOCKED | EXTENT_BOUNDARY);
3325 goto out;
3326
3327 }
3328 set_page_dirty(page);
3329
3330 unlock_extent(&BTRFS_I(inode)->io_tree,
3331 page_start, page_end);
3332 unlock_page(page);
3333 put_page(page);
3334
3335 index++;
3336 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE,
3337 false);
3338 balance_dirty_pages_ratelimited(inode->i_mapping);
3339 btrfs_throttle(fs_info);
3340 }
3341 WARN_ON(nr != cluster->nr);
3342 out:
3343 kfree(ra);
3344 return ret;
3345 }
3346
3347 static noinline_for_stack
3348 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3349 struct file_extent_cluster *cluster)
3350 {
3351 int ret;
3352
3353 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3354 ret = relocate_file_extent_cluster(inode, cluster);
3355 if (ret)
3356 return ret;
3357 cluster->nr = 0;
3358 }
3359
3360 if (!cluster->nr)
3361 cluster->start = extent_key->objectid;
3362 else
3363 BUG_ON(cluster->nr >= MAX_EXTENTS);
3364 cluster->end = extent_key->objectid + extent_key->offset - 1;
3365 cluster->boundary[cluster->nr] = extent_key->objectid;
3366 cluster->nr++;
3367
3368 if (cluster->nr >= MAX_EXTENTS) {
3369 ret = relocate_file_extent_cluster(inode, cluster);
3370 if (ret)
3371 return ret;
3372 cluster->nr = 0;
3373 }
3374 return 0;
3375 }
3376
3377 /*
3378 * helper to add a tree block to the list.
3379 * the major work is getting the generation and level of the block
3380 */
3381 static int add_tree_block(struct reloc_control *rc,
3382 struct btrfs_key *extent_key,
3383 struct btrfs_path *path,
3384 struct rb_root *blocks)
3385 {
3386 struct extent_buffer *eb;
3387 struct btrfs_extent_item *ei;
3388 struct btrfs_tree_block_info *bi;
3389 struct tree_block *block;
3390 struct rb_node *rb_node;
3391 u32 item_size;
3392 int level = -1;
3393 u64 generation;
3394
3395 eb = path->nodes[0];
3396 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3397
3398 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3399 item_size >= sizeof(*ei) + sizeof(*bi)) {
3400 ei = btrfs_item_ptr(eb, path->slots[0],
3401 struct btrfs_extent_item);
3402 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3403 bi = (struct btrfs_tree_block_info *)(ei + 1);
3404 level = btrfs_tree_block_level(eb, bi);
3405 } else {
3406 level = (int)extent_key->offset;
3407 }
3408 generation = btrfs_extent_generation(eb, ei);
3409 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3410 btrfs_print_v0_err(eb->fs_info);
3411 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3412 return -EINVAL;
3413 } else {
3414 BUG();
3415 }
3416
3417 btrfs_release_path(path);
3418
3419 BUG_ON(level == -1);
3420
3421 block = kmalloc(sizeof(*block), GFP_NOFS);
3422 if (!block)
3423 return -ENOMEM;
3424
3425 block->bytenr = extent_key->objectid;
3426 block->key.objectid = rc->extent_root->fs_info->nodesize;
3427 block->key.offset = generation;
3428 block->level = level;
3429 block->key_ready = 0;
3430
3431 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3432 if (rb_node)
3433 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3434
3435 return 0;
3436 }
3437
3438 /*
3439 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3440 */
3441 static int __add_tree_block(struct reloc_control *rc,
3442 u64 bytenr, u32 blocksize,
3443 struct rb_root *blocks)
3444 {
3445 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3446 struct btrfs_path *path;
3447 struct btrfs_key key;
3448 int ret;
3449 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3450
3451 if (tree_block_processed(bytenr, rc))
3452 return 0;
3453
3454 if (tree_search(blocks, bytenr))
3455 return 0;
3456
3457 path = btrfs_alloc_path();
3458 if (!path)
3459 return -ENOMEM;
3460 again:
3461 key.objectid = bytenr;
3462 if (skinny) {
3463 key.type = BTRFS_METADATA_ITEM_KEY;
3464 key.offset = (u64)-1;
3465 } else {
3466 key.type = BTRFS_EXTENT_ITEM_KEY;
3467 key.offset = blocksize;
3468 }
3469
3470 path->search_commit_root = 1;
3471 path->skip_locking = 1;
3472 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3473 if (ret < 0)
3474 goto out;
3475
3476 if (ret > 0 && skinny) {
3477 if (path->slots[0]) {
3478 path->slots[0]--;
3479 btrfs_item_key_to_cpu(path->nodes[0], &key,
3480 path->slots[0]);
3481 if (key.objectid == bytenr &&
3482 (key.type == BTRFS_METADATA_ITEM_KEY ||
3483 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3484 key.offset == blocksize)))
3485 ret = 0;
3486 }
3487
3488 if (ret) {
3489 skinny = false;
3490 btrfs_release_path(path);
3491 goto again;
3492 }
3493 }
3494 if (ret) {
3495 ASSERT(ret == 1);
3496 btrfs_print_leaf(path->nodes[0]);
3497 btrfs_err(fs_info,
3498 "tree block extent item (%llu) is not found in extent tree",
3499 bytenr);
3500 WARN_ON(1);
3501 ret = -EINVAL;
3502 goto out;
3503 }
3504
3505 ret = add_tree_block(rc, &key, path, blocks);
3506 out:
3507 btrfs_free_path(path);
3508 return ret;
3509 }
3510
3511 /*
3512 * helper to check if the block use full backrefs for pointers in it
3513 */
3514 static int block_use_full_backref(struct reloc_control *rc,
3515 struct extent_buffer *eb)
3516 {
3517 u64 flags;
3518 int ret;
3519
3520 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3521 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3522 return 1;
3523
3524 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3525 eb->start, btrfs_header_level(eb), 1,
3526 NULL, &flags);
3527 BUG_ON(ret);
3528
3529 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3530 ret = 1;
3531 else
3532 ret = 0;
3533 return ret;
3534 }
3535
3536 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3537 struct btrfs_block_group_cache *block_group,
3538 struct inode *inode,
3539 u64 ino)
3540 {
3541 struct btrfs_key key;
3542 struct btrfs_root *root = fs_info->tree_root;
3543 struct btrfs_trans_handle *trans;
3544 int ret = 0;
3545
3546 if (inode)
3547 goto truncate;
3548
3549 key.objectid = ino;
3550 key.type = BTRFS_INODE_ITEM_KEY;
3551 key.offset = 0;
3552
3553 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3554 if (IS_ERR(inode))
3555 return -ENOENT;
3556
3557 truncate:
3558 ret = btrfs_check_trunc_cache_free_space(fs_info,
3559 &fs_info->global_block_rsv);
3560 if (ret)
3561 goto out;
3562
3563 trans = btrfs_join_transaction(root);
3564 if (IS_ERR(trans)) {
3565 ret = PTR_ERR(trans);
3566 goto out;
3567 }
3568
3569 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3570
3571 btrfs_end_transaction(trans);
3572 btrfs_btree_balance_dirty(fs_info);
3573 out:
3574 iput(inode);
3575 return ret;
3576 }
3577
3578 /*
3579 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3580 * this function scans fs tree to find blocks reference the data extent
3581 */
3582 static int find_data_references(struct reloc_control *rc,
3583 struct btrfs_key *extent_key,
3584 struct extent_buffer *leaf,
3585 struct btrfs_extent_data_ref *ref,
3586 struct rb_root *blocks)
3587 {
3588 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3589 struct btrfs_path *path;
3590 struct tree_block *block;
3591 struct btrfs_root *root;
3592 struct btrfs_file_extent_item *fi;
3593 struct rb_node *rb_node;
3594 struct btrfs_key key;
3595 u64 ref_root;
3596 u64 ref_objectid;
3597 u64 ref_offset;
3598 u32 ref_count;
3599 u32 nritems;
3600 int err = 0;
3601 int added = 0;
3602 int counted;
3603 int ret;
3604
3605 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3606 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3607 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3608 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3609
3610 /*
3611 * This is an extent belonging to the free space cache, lets just delete
3612 * it and redo the search.
3613 */
3614 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3615 ret = delete_block_group_cache(fs_info, rc->block_group,
3616 NULL, ref_objectid);
3617 if (ret != -ENOENT)
3618 return ret;
3619 ret = 0;
3620 }
3621
3622 path = btrfs_alloc_path();
3623 if (!path)
3624 return -ENOMEM;
3625 path->reada = READA_FORWARD;
3626
3627 root = read_fs_root(fs_info, ref_root);
3628 if (IS_ERR(root)) {
3629 err = PTR_ERR(root);
3630 goto out;
3631 }
3632
3633 key.objectid = ref_objectid;
3634 key.type = BTRFS_EXTENT_DATA_KEY;
3635 if (ref_offset > ((u64)-1 << 32))
3636 key.offset = 0;
3637 else
3638 key.offset = ref_offset;
3639
3640 path->search_commit_root = 1;
3641 path->skip_locking = 1;
3642 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3643 if (ret < 0) {
3644 err = ret;
3645 goto out;
3646 }
3647
3648 leaf = path->nodes[0];
3649 nritems = btrfs_header_nritems(leaf);
3650 /*
3651 * the references in tree blocks that use full backrefs
3652 * are not counted in
3653 */
3654 if (block_use_full_backref(rc, leaf))
3655 counted = 0;
3656 else
3657 counted = 1;
3658 rb_node = tree_search(blocks, leaf->start);
3659 if (rb_node) {
3660 if (counted)
3661 added = 1;
3662 else
3663 path->slots[0] = nritems;
3664 }
3665
3666 while (ref_count > 0) {
3667 while (path->slots[0] >= nritems) {
3668 ret = btrfs_next_leaf(root, path);
3669 if (ret < 0) {
3670 err = ret;
3671 goto out;
3672 }
3673 if (WARN_ON(ret > 0))
3674 goto out;
3675
3676 leaf = path->nodes[0];
3677 nritems = btrfs_header_nritems(leaf);
3678 added = 0;
3679
3680 if (block_use_full_backref(rc, leaf))
3681 counted = 0;
3682 else
3683 counted = 1;
3684 rb_node = tree_search(blocks, leaf->start);
3685 if (rb_node) {
3686 if (counted)
3687 added = 1;
3688 else
3689 path->slots[0] = nritems;
3690 }
3691 }
3692
3693 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3694 if (WARN_ON(key.objectid != ref_objectid ||
3695 key.type != BTRFS_EXTENT_DATA_KEY))
3696 break;
3697
3698 fi = btrfs_item_ptr(leaf, path->slots[0],
3699 struct btrfs_file_extent_item);
3700
3701 if (btrfs_file_extent_type(leaf, fi) ==
3702 BTRFS_FILE_EXTENT_INLINE)
3703 goto next;
3704
3705 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3706 extent_key->objectid)
3707 goto next;
3708
3709 key.offset -= btrfs_file_extent_offset(leaf, fi);
3710 if (key.offset != ref_offset)
3711 goto next;
3712
3713 if (counted)
3714 ref_count--;
3715 if (added)
3716 goto next;
3717
3718 if (!tree_block_processed(leaf->start, rc)) {
3719 block = kmalloc(sizeof(*block), GFP_NOFS);
3720 if (!block) {
3721 err = -ENOMEM;
3722 break;
3723 }
3724 block->bytenr = leaf->start;
3725 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3726 block->level = 0;
3727 block->key_ready = 1;
3728 rb_node = tree_insert(blocks, block->bytenr,
3729 &block->rb_node);
3730 if (rb_node)
3731 backref_tree_panic(rb_node, -EEXIST,
3732 block->bytenr);
3733 }
3734 if (counted)
3735 added = 1;
3736 else
3737 path->slots[0] = nritems;
3738 next:
3739 path->slots[0]++;
3740
3741 }
3742 out:
3743 btrfs_free_path(path);
3744 return err;
3745 }
3746
3747 /*
3748 * helper to find all tree blocks that reference a given data extent
3749 */
3750 static noinline_for_stack
3751 int add_data_references(struct reloc_control *rc,
3752 struct btrfs_key *extent_key,
3753 struct btrfs_path *path,
3754 struct rb_root *blocks)
3755 {
3756 struct btrfs_key key;
3757 struct extent_buffer *eb;
3758 struct btrfs_extent_data_ref *dref;
3759 struct btrfs_extent_inline_ref *iref;
3760 unsigned long ptr;
3761 unsigned long end;
3762 u32 blocksize = rc->extent_root->fs_info->nodesize;
3763 int ret = 0;
3764 int err = 0;
3765
3766 eb = path->nodes[0];
3767 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3768 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3769 ptr += sizeof(struct btrfs_extent_item);
3770
3771 while (ptr < end) {
3772 iref = (struct btrfs_extent_inline_ref *)ptr;
3773 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3774 BTRFS_REF_TYPE_DATA);
3775 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3776 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3777 ret = __add_tree_block(rc, key.offset, blocksize,
3778 blocks);
3779 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3780 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3781 ret = find_data_references(rc, extent_key,
3782 eb, dref, blocks);
3783 } else {
3784 ret = -EUCLEAN;
3785 btrfs_err(rc->extent_root->fs_info,
3786 "extent %llu slot %d has an invalid inline ref type",
3787 eb->start, path->slots[0]);
3788 }
3789 if (ret) {
3790 err = ret;
3791 goto out;
3792 }
3793 ptr += btrfs_extent_inline_ref_size(key.type);
3794 }
3795 WARN_ON(ptr > end);
3796
3797 while (1) {
3798 cond_resched();
3799 eb = path->nodes[0];
3800 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3801 ret = btrfs_next_leaf(rc->extent_root, path);
3802 if (ret < 0) {
3803 err = ret;
3804 break;
3805 }
3806 if (ret > 0)
3807 break;
3808 eb = path->nodes[0];
3809 }
3810
3811 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3812 if (key.objectid != extent_key->objectid)
3813 break;
3814
3815 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3816 ret = __add_tree_block(rc, key.offset, blocksize,
3817 blocks);
3818 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3819 dref = btrfs_item_ptr(eb, path->slots[0],
3820 struct btrfs_extent_data_ref);
3821 ret = find_data_references(rc, extent_key,
3822 eb, dref, blocks);
3823 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
3824 btrfs_print_v0_err(eb->fs_info);
3825 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3826 ret = -EINVAL;
3827 } else {
3828 ret = 0;
3829 }
3830 if (ret) {
3831 err = ret;
3832 break;
3833 }
3834 path->slots[0]++;
3835 }
3836 out:
3837 btrfs_release_path(path);
3838 if (err)
3839 free_block_list(blocks);
3840 return err;
3841 }
3842
3843 /*
3844 * helper to find next unprocessed extent
3845 */
3846 static noinline_for_stack
3847 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3848 struct btrfs_key *extent_key)
3849 {
3850 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3851 struct btrfs_key key;
3852 struct extent_buffer *leaf;
3853 u64 start, end, last;
3854 int ret;
3855
3856 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3857 while (1) {
3858 cond_resched();
3859 if (rc->search_start >= last) {
3860 ret = 1;
3861 break;
3862 }
3863
3864 key.objectid = rc->search_start;
3865 key.type = BTRFS_EXTENT_ITEM_KEY;
3866 key.offset = 0;
3867
3868 path->search_commit_root = 1;
3869 path->skip_locking = 1;
3870 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3871 0, 0);
3872 if (ret < 0)
3873 break;
3874 next:
3875 leaf = path->nodes[0];
3876 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3877 ret = btrfs_next_leaf(rc->extent_root, path);
3878 if (ret != 0)
3879 break;
3880 leaf = path->nodes[0];
3881 }
3882
3883 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3884 if (key.objectid >= last) {
3885 ret = 1;
3886 break;
3887 }
3888
3889 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3890 key.type != BTRFS_METADATA_ITEM_KEY) {
3891 path->slots[0]++;
3892 goto next;
3893 }
3894
3895 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3896 key.objectid + key.offset <= rc->search_start) {
3897 path->slots[0]++;
3898 goto next;
3899 }
3900
3901 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3902 key.objectid + fs_info->nodesize <=
3903 rc->search_start) {
3904 path->slots[0]++;
3905 goto next;
3906 }
3907
3908 ret = find_first_extent_bit(&rc->processed_blocks,
3909 key.objectid, &start, &end,
3910 EXTENT_DIRTY, NULL);
3911
3912 if (ret == 0 && start <= key.objectid) {
3913 btrfs_release_path(path);
3914 rc->search_start = end + 1;
3915 } else {
3916 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3917 rc->search_start = key.objectid + key.offset;
3918 else
3919 rc->search_start = key.objectid +
3920 fs_info->nodesize;
3921 memcpy(extent_key, &key, sizeof(key));
3922 return 0;
3923 }
3924 }
3925 btrfs_release_path(path);
3926 return ret;
3927 }
3928
3929 static void set_reloc_control(struct reloc_control *rc)
3930 {
3931 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3932
3933 mutex_lock(&fs_info->reloc_mutex);
3934 fs_info->reloc_ctl = rc;
3935 mutex_unlock(&fs_info->reloc_mutex);
3936 }
3937
3938 static void unset_reloc_control(struct reloc_control *rc)
3939 {
3940 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3941
3942 mutex_lock(&fs_info->reloc_mutex);
3943 fs_info->reloc_ctl = NULL;
3944 mutex_unlock(&fs_info->reloc_mutex);
3945 }
3946
3947 static int check_extent_flags(u64 flags)
3948 {
3949 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3950 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3951 return 1;
3952 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3953 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3954 return 1;
3955 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3956 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3957 return 1;
3958 return 0;
3959 }
3960
3961 static noinline_for_stack
3962 int prepare_to_relocate(struct reloc_control *rc)
3963 {
3964 struct btrfs_trans_handle *trans;
3965 int ret;
3966
3967 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3968 BTRFS_BLOCK_RSV_TEMP);
3969 if (!rc->block_rsv)
3970 return -ENOMEM;
3971
3972 memset(&rc->cluster, 0, sizeof(rc->cluster));
3973 rc->search_start = rc->block_group->key.objectid;
3974 rc->extents_found = 0;
3975 rc->nodes_relocated = 0;
3976 rc->merging_rsv_size = 0;
3977 rc->reserved_bytes = 0;
3978 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3979 RELOCATION_RESERVED_NODES;
3980 ret = btrfs_block_rsv_refill(rc->extent_root,
3981 rc->block_rsv, rc->block_rsv->size,
3982 BTRFS_RESERVE_FLUSH_ALL);
3983 if (ret)
3984 return ret;
3985
3986 rc->create_reloc_tree = 1;
3987 set_reloc_control(rc);
3988
3989 trans = btrfs_join_transaction(rc->extent_root);
3990 if (IS_ERR(trans)) {
3991 unset_reloc_control(rc);
3992 /*
3993 * extent tree is not a ref_cow tree and has no reloc_root to
3994 * cleanup. And callers are responsible to free the above
3995 * block rsv.
3996 */
3997 return PTR_ERR(trans);
3998 }
3999 btrfs_commit_transaction(trans);
4000 return 0;
4001 }
4002
4003 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4004 {
4005 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
4006 struct rb_root blocks = RB_ROOT;
4007 struct btrfs_key key;
4008 struct btrfs_trans_handle *trans = NULL;
4009 struct btrfs_path *path;
4010 struct btrfs_extent_item *ei;
4011 u64 flags;
4012 u32 item_size;
4013 int ret;
4014 int err = 0;
4015 int progress = 0;
4016
4017 path = btrfs_alloc_path();
4018 if (!path)
4019 return -ENOMEM;
4020 path->reada = READA_FORWARD;
4021
4022 ret = prepare_to_relocate(rc);
4023 if (ret) {
4024 err = ret;
4025 goto out_free;
4026 }
4027
4028 while (1) {
4029 rc->reserved_bytes = 0;
4030 ret = btrfs_block_rsv_refill(rc->extent_root,
4031 rc->block_rsv, rc->block_rsv->size,
4032 BTRFS_RESERVE_FLUSH_ALL);
4033 if (ret) {
4034 err = ret;
4035 break;
4036 }
4037 progress++;
4038 trans = btrfs_start_transaction(rc->extent_root, 0);
4039 if (IS_ERR(trans)) {
4040 err = PTR_ERR(trans);
4041 trans = NULL;
4042 break;
4043 }
4044 restart:
4045 if (update_backref_cache(trans, &rc->backref_cache)) {
4046 btrfs_end_transaction(trans);
4047 trans = NULL;
4048 continue;
4049 }
4050
4051 ret = find_next_extent(rc, path, &key);
4052 if (ret < 0)
4053 err = ret;
4054 if (ret != 0)
4055 break;
4056
4057 rc->extents_found++;
4058
4059 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4060 struct btrfs_extent_item);
4061 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4062 if (item_size >= sizeof(*ei)) {
4063 flags = btrfs_extent_flags(path->nodes[0], ei);
4064 ret = check_extent_flags(flags);
4065 BUG_ON(ret);
4066 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
4067 err = -EINVAL;
4068 btrfs_print_v0_err(trans->fs_info);
4069 btrfs_abort_transaction(trans, err);
4070 break;
4071 } else {
4072 BUG();
4073 }
4074
4075 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4076 ret = add_tree_block(rc, &key, path, &blocks);
4077 } else if (rc->stage == UPDATE_DATA_PTRS &&
4078 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4079 ret = add_data_references(rc, &key, path, &blocks);
4080 } else {
4081 btrfs_release_path(path);
4082 ret = 0;
4083 }
4084 if (ret < 0) {
4085 err = ret;
4086 break;
4087 }
4088
4089 if (!RB_EMPTY_ROOT(&blocks)) {
4090 ret = relocate_tree_blocks(trans, rc, &blocks);
4091 if (ret < 0) {
4092 /*
4093 * if we fail to relocate tree blocks, force to update
4094 * backref cache when committing transaction.
4095 */
4096 rc->backref_cache.last_trans = trans->transid - 1;
4097
4098 if (ret != -EAGAIN) {
4099 err = ret;
4100 break;
4101 }
4102 rc->extents_found--;
4103 rc->search_start = key.objectid;
4104 }
4105 }
4106
4107 btrfs_end_transaction_throttle(trans);
4108 btrfs_btree_balance_dirty(fs_info);
4109 trans = NULL;
4110
4111 if (rc->stage == MOVE_DATA_EXTENTS &&
4112 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4113 rc->found_file_extent = 1;
4114 ret = relocate_data_extent(rc->data_inode,
4115 &key, &rc->cluster);
4116 if (ret < 0) {
4117 err = ret;
4118 break;
4119 }
4120 }
4121 }
4122 if (trans && progress && err == -ENOSPC) {
4123 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
4124 if (ret == 1) {
4125 err = 0;
4126 progress = 0;
4127 goto restart;
4128 }
4129 }
4130
4131 btrfs_release_path(path);
4132 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4133
4134 if (trans) {
4135 btrfs_end_transaction_throttle(trans);
4136 btrfs_btree_balance_dirty(fs_info);
4137 }
4138
4139 if (!err) {
4140 ret = relocate_file_extent_cluster(rc->data_inode,
4141 &rc->cluster);
4142 if (ret < 0)
4143 err = ret;
4144 }
4145
4146 rc->create_reloc_tree = 0;
4147 set_reloc_control(rc);
4148
4149 backref_cache_cleanup(&rc->backref_cache);
4150 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4151
4152 err = prepare_to_merge(rc, err);
4153
4154 merge_reloc_roots(rc);
4155
4156 rc->merge_reloc_tree = 0;
4157 unset_reloc_control(rc);
4158 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4159
4160 /* get rid of pinned extents */
4161 trans = btrfs_join_transaction(rc->extent_root);
4162 if (IS_ERR(trans)) {
4163 err = PTR_ERR(trans);
4164 goto out_free;
4165 }
4166 btrfs_commit_transaction(trans);
4167 ret = clean_dirty_subvols(rc);
4168 if (ret < 0 && !err)
4169 err = ret;
4170 out_free:
4171 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4172 btrfs_free_path(path);
4173 return err;
4174 }
4175
4176 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4177 struct btrfs_root *root, u64 objectid)
4178 {
4179 struct btrfs_path *path;
4180 struct btrfs_inode_item *item;
4181 struct extent_buffer *leaf;
4182 int ret;
4183
4184 path = btrfs_alloc_path();
4185 if (!path)
4186 return -ENOMEM;
4187
4188 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4189 if (ret)
4190 goto out;
4191
4192 leaf = path->nodes[0];
4193 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4194 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4195 btrfs_set_inode_generation(leaf, item, 1);
4196 btrfs_set_inode_size(leaf, item, 0);
4197 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4198 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4199 BTRFS_INODE_PREALLOC);
4200 btrfs_mark_buffer_dirty(leaf);
4201 out:
4202 btrfs_free_path(path);
4203 return ret;
4204 }
4205
4206 /*
4207 * helper to create inode for data relocation.
4208 * the inode is in data relocation tree and its link count is 0
4209 */
4210 static noinline_for_stack
4211 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4212 struct btrfs_block_group_cache *group)
4213 {
4214 struct inode *inode = NULL;
4215 struct btrfs_trans_handle *trans;
4216 struct btrfs_root *root;
4217 struct btrfs_key key;
4218 u64 objectid;
4219 int err = 0;
4220
4221 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4222 if (IS_ERR(root))
4223 return ERR_CAST(root);
4224
4225 trans = btrfs_start_transaction(root, 6);
4226 if (IS_ERR(trans))
4227 return ERR_CAST(trans);
4228
4229 err = btrfs_find_free_objectid(root, &objectid);
4230 if (err)
4231 goto out;
4232
4233 err = __insert_orphan_inode(trans, root, objectid);
4234 BUG_ON(err);
4235
4236 key.objectid = objectid;
4237 key.type = BTRFS_INODE_ITEM_KEY;
4238 key.offset = 0;
4239 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4240 BUG_ON(IS_ERR(inode));
4241 BTRFS_I(inode)->index_cnt = group->key.objectid;
4242
4243 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4244 out:
4245 btrfs_end_transaction(trans);
4246 btrfs_btree_balance_dirty(fs_info);
4247 if (err) {
4248 if (inode)
4249 iput(inode);
4250 inode = ERR_PTR(err);
4251 }
4252 return inode;
4253 }
4254
4255 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4256 {
4257 struct reloc_control *rc;
4258
4259 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4260 if (!rc)
4261 return NULL;
4262
4263 INIT_LIST_HEAD(&rc->reloc_roots);
4264 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
4265 backref_cache_init(&rc->backref_cache);
4266 mapping_tree_init(&rc->reloc_root_tree);
4267 extent_io_tree_init(fs_info, &rc->processed_blocks,
4268 IO_TREE_RELOC_BLOCKS, NULL);
4269 return rc;
4270 }
4271
4272 /*
4273 * Print the block group being relocated
4274 */
4275 static void describe_relocation(struct btrfs_fs_info *fs_info,
4276 struct btrfs_block_group_cache *block_group)
4277 {
4278 char buf[128] = {'\0'};
4279
4280 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
4281
4282 btrfs_info(fs_info,
4283 "relocating block group %llu flags %s",
4284 block_group->key.objectid, buf);
4285 }
4286
4287 /*
4288 * function to relocate all extents in a block group.
4289 */
4290 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4291 {
4292 struct btrfs_block_group_cache *bg;
4293 struct btrfs_root *extent_root = fs_info->extent_root;
4294 struct reloc_control *rc;
4295 struct inode *inode;
4296 struct btrfs_path *path;
4297 int ret;
4298 int rw = 0;
4299 int err = 0;
4300
4301 bg = btrfs_lookup_block_group(fs_info, group_start);
4302 if (!bg)
4303 return -ENOENT;
4304
4305 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4306 btrfs_put_block_group(bg);
4307 return -ETXTBSY;
4308 }
4309
4310 rc = alloc_reloc_control(fs_info);
4311 if (!rc) {
4312 btrfs_put_block_group(bg);
4313 return -ENOMEM;
4314 }
4315
4316 rc->extent_root = extent_root;
4317 rc->block_group = bg;
4318
4319 ret = btrfs_inc_block_group_ro(rc->block_group);
4320 if (ret) {
4321 err = ret;
4322 goto out;
4323 }
4324 rw = 1;
4325
4326 path = btrfs_alloc_path();
4327 if (!path) {
4328 err = -ENOMEM;
4329 goto out;
4330 }
4331
4332 inode = lookup_free_space_inode(rc->block_group, path);
4333 btrfs_free_path(path);
4334
4335 if (!IS_ERR(inode))
4336 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4337 else
4338 ret = PTR_ERR(inode);
4339
4340 if (ret && ret != -ENOENT) {
4341 err = ret;
4342 goto out;
4343 }
4344
4345 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4346 if (IS_ERR(rc->data_inode)) {
4347 err = PTR_ERR(rc->data_inode);
4348 rc->data_inode = NULL;
4349 goto out;
4350 }
4351
4352 describe_relocation(fs_info, rc->block_group);
4353
4354 btrfs_wait_block_group_reservations(rc->block_group);
4355 btrfs_wait_nocow_writers(rc->block_group);
4356 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4357 rc->block_group->key.objectid,
4358 rc->block_group->key.offset);
4359
4360 while (1) {
4361 mutex_lock(&fs_info->cleaner_mutex);
4362 ret = relocate_block_group(rc);
4363 mutex_unlock(&fs_info->cleaner_mutex);
4364 if (ret < 0)
4365 err = ret;
4366
4367 /*
4368 * We may have gotten ENOSPC after we already dirtied some
4369 * extents. If writeout happens while we're relocating a
4370 * different block group we could end up hitting the
4371 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4372 * btrfs_reloc_cow_block. Make sure we write everything out
4373 * properly so we don't trip over this problem, and then break
4374 * out of the loop if we hit an error.
4375 */
4376 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4377 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4378 (u64)-1);
4379 if (ret)
4380 err = ret;
4381 invalidate_mapping_pages(rc->data_inode->i_mapping,
4382 0, -1);
4383 rc->stage = UPDATE_DATA_PTRS;
4384 }
4385
4386 if (err < 0)
4387 goto out;
4388
4389 if (rc->extents_found == 0)
4390 break;
4391
4392 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4393
4394 }
4395
4396 WARN_ON(rc->block_group->pinned > 0);
4397 WARN_ON(rc->block_group->reserved > 0);
4398 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4399 out:
4400 if (err && rw)
4401 btrfs_dec_block_group_ro(rc->block_group);
4402 iput(rc->data_inode);
4403 btrfs_put_block_group(rc->block_group);
4404 kfree(rc);
4405 return err;
4406 }
4407
4408 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4409 {
4410 struct btrfs_fs_info *fs_info = root->fs_info;
4411 struct btrfs_trans_handle *trans;
4412 int ret, err;
4413
4414 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4415 if (IS_ERR(trans))
4416 return PTR_ERR(trans);
4417
4418 memset(&root->root_item.drop_progress, 0,
4419 sizeof(root->root_item.drop_progress));
4420 root->root_item.drop_level = 0;
4421 btrfs_set_root_refs(&root->root_item, 0);
4422 ret = btrfs_update_root(trans, fs_info->tree_root,
4423 &root->root_key, &root->root_item);
4424
4425 err = btrfs_end_transaction(trans);
4426 if (err)
4427 return err;
4428 return ret;
4429 }
4430
4431 /*
4432 * recover relocation interrupted by system crash.
4433 *
4434 * this function resumes merging reloc trees with corresponding fs trees.
4435 * this is important for keeping the sharing of tree blocks
4436 */
4437 int btrfs_recover_relocation(struct btrfs_root *root)
4438 {
4439 struct btrfs_fs_info *fs_info = root->fs_info;
4440 LIST_HEAD(reloc_roots);
4441 struct btrfs_key key;
4442 struct btrfs_root *fs_root;
4443 struct btrfs_root *reloc_root;
4444 struct btrfs_path *path;
4445 struct extent_buffer *leaf;
4446 struct reloc_control *rc = NULL;
4447 struct btrfs_trans_handle *trans;
4448 int ret;
4449 int err = 0;
4450
4451 path = btrfs_alloc_path();
4452 if (!path)
4453 return -ENOMEM;
4454 path->reada = READA_BACK;
4455
4456 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4457 key.type = BTRFS_ROOT_ITEM_KEY;
4458 key.offset = (u64)-1;
4459
4460 while (1) {
4461 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4462 path, 0, 0);
4463 if (ret < 0) {
4464 err = ret;
4465 goto out;
4466 }
4467 if (ret > 0) {
4468 if (path->slots[0] == 0)
4469 break;
4470 path->slots[0]--;
4471 }
4472 leaf = path->nodes[0];
4473 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4474 btrfs_release_path(path);
4475
4476 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4477 key.type != BTRFS_ROOT_ITEM_KEY)
4478 break;
4479
4480 reloc_root = btrfs_read_fs_root(root, &key);
4481 if (IS_ERR(reloc_root)) {
4482 err = PTR_ERR(reloc_root);
4483 goto out;
4484 }
4485
4486 list_add(&reloc_root->root_list, &reloc_roots);
4487
4488 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4489 fs_root = read_fs_root(fs_info,
4490 reloc_root->root_key.offset);
4491 if (IS_ERR(fs_root)) {
4492 ret = PTR_ERR(fs_root);
4493 if (ret != -ENOENT) {
4494 err = ret;
4495 goto out;
4496 }
4497 ret = mark_garbage_root(reloc_root);
4498 if (ret < 0) {
4499 err = ret;
4500 goto out;
4501 }
4502 }
4503 }
4504
4505 if (key.offset == 0)
4506 break;
4507
4508 key.offset--;
4509 }
4510 btrfs_release_path(path);
4511
4512 if (list_empty(&reloc_roots))
4513 goto out;
4514
4515 rc = alloc_reloc_control(fs_info);
4516 if (!rc) {
4517 err = -ENOMEM;
4518 goto out;
4519 }
4520
4521 rc->extent_root = fs_info->extent_root;
4522
4523 set_reloc_control(rc);
4524
4525 trans = btrfs_join_transaction(rc->extent_root);
4526 if (IS_ERR(trans)) {
4527 unset_reloc_control(rc);
4528 err = PTR_ERR(trans);
4529 goto out_free;
4530 }
4531
4532 rc->merge_reloc_tree = 1;
4533
4534 while (!list_empty(&reloc_roots)) {
4535 reloc_root = list_entry(reloc_roots.next,
4536 struct btrfs_root, root_list);
4537 list_del(&reloc_root->root_list);
4538
4539 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4540 list_add_tail(&reloc_root->root_list,
4541 &rc->reloc_roots);
4542 continue;
4543 }
4544
4545 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4546 if (IS_ERR(fs_root)) {
4547 err = PTR_ERR(fs_root);
4548 goto out_free;
4549 }
4550
4551 err = __add_reloc_root(reloc_root);
4552 BUG_ON(err < 0); /* -ENOMEM or logic error */
4553 fs_root->reloc_root = reloc_root;
4554 }
4555
4556 err = btrfs_commit_transaction(trans);
4557 if (err)
4558 goto out_free;
4559
4560 merge_reloc_roots(rc);
4561
4562 unset_reloc_control(rc);
4563
4564 trans = btrfs_join_transaction(rc->extent_root);
4565 if (IS_ERR(trans)) {
4566 err = PTR_ERR(trans);
4567 goto out_free;
4568 }
4569 err = btrfs_commit_transaction(trans);
4570
4571 ret = clean_dirty_subvols(rc);
4572 if (ret < 0 && !err)
4573 err = ret;
4574 out_free:
4575 kfree(rc);
4576 out:
4577 if (!list_empty(&reloc_roots))
4578 free_reloc_roots(&reloc_roots);
4579
4580 btrfs_free_path(path);
4581
4582 if (err == 0) {
4583 /* cleanup orphan inode in data relocation tree */
4584 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4585 if (IS_ERR(fs_root))
4586 err = PTR_ERR(fs_root);
4587 else
4588 err = btrfs_orphan_cleanup(fs_root);
4589 }
4590 return err;
4591 }
4592
4593 /*
4594 * helper to add ordered checksum for data relocation.
4595 *
4596 * cloning checksum properly handles the nodatasum extents.
4597 * it also saves CPU time to re-calculate the checksum.
4598 */
4599 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4600 {
4601 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4602 struct btrfs_ordered_sum *sums;
4603 struct btrfs_ordered_extent *ordered;
4604 int ret;
4605 u64 disk_bytenr;
4606 u64 new_bytenr;
4607 LIST_HEAD(list);
4608
4609 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4610 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4611
4612 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4613 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4614 disk_bytenr + len - 1, &list, 0);
4615 if (ret)
4616 goto out;
4617
4618 while (!list_empty(&list)) {
4619 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4620 list_del_init(&sums->list);
4621
4622 /*
4623 * We need to offset the new_bytenr based on where the csum is.
4624 * We need to do this because we will read in entire prealloc
4625 * extents but we may have written to say the middle of the
4626 * prealloc extent, so we need to make sure the csum goes with
4627 * the right disk offset.
4628 *
4629 * We can do this because the data reloc inode refers strictly
4630 * to the on disk bytes, so we don't have to worry about
4631 * disk_len vs real len like with real inodes since it's all
4632 * disk length.
4633 */
4634 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4635 sums->bytenr = new_bytenr;
4636
4637 btrfs_add_ordered_sum(ordered, sums);
4638 }
4639 out:
4640 btrfs_put_ordered_extent(ordered);
4641 return ret;
4642 }
4643
4644 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4645 struct btrfs_root *root, struct extent_buffer *buf,
4646 struct extent_buffer *cow)
4647 {
4648 struct btrfs_fs_info *fs_info = root->fs_info;
4649 struct reloc_control *rc;
4650 struct backref_node *node;
4651 int first_cow = 0;
4652 int level;
4653 int ret = 0;
4654
4655 rc = fs_info->reloc_ctl;
4656 if (!rc)
4657 return 0;
4658
4659 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4660 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4661
4662 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4663 if (buf == root->node)
4664 __update_reloc_root(root, cow->start);
4665 }
4666
4667 level = btrfs_header_level(buf);
4668 if (btrfs_header_generation(buf) <=
4669 btrfs_root_last_snapshot(&root->root_item))
4670 first_cow = 1;
4671
4672 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4673 rc->create_reloc_tree) {
4674 WARN_ON(!first_cow && level == 0);
4675
4676 node = rc->backref_cache.path[level];
4677 BUG_ON(node->bytenr != buf->start &&
4678 node->new_bytenr != buf->start);
4679
4680 drop_node_buffer(node);
4681 extent_buffer_get(cow);
4682 node->eb = cow;
4683 node->new_bytenr = cow->start;
4684
4685 if (!node->pending) {
4686 list_move_tail(&node->list,
4687 &rc->backref_cache.pending[level]);
4688 node->pending = 1;
4689 }
4690
4691 if (first_cow)
4692 __mark_block_processed(rc, node);
4693
4694 if (first_cow && level > 0)
4695 rc->nodes_relocated += buf->len;
4696 }
4697
4698 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4699 ret = replace_file_extents(trans, rc, root, cow);
4700 return ret;
4701 }
4702
4703 /*
4704 * called before creating snapshot. it calculates metadata reservation
4705 * required for relocating tree blocks in the snapshot
4706 */
4707 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4708 u64 *bytes_to_reserve)
4709 {
4710 struct btrfs_root *root = pending->root;
4711 struct reloc_control *rc = root->fs_info->reloc_ctl;
4712
4713 if (!root->reloc_root || !rc)
4714 return;
4715
4716 if (!rc->merge_reloc_tree)
4717 return;
4718
4719 root = root->reloc_root;
4720 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4721 /*
4722 * relocation is in the stage of merging trees. the space
4723 * used by merging a reloc tree is twice the size of
4724 * relocated tree nodes in the worst case. half for cowing
4725 * the reloc tree, half for cowing the fs tree. the space
4726 * used by cowing the reloc tree will be freed after the
4727 * tree is dropped. if we create snapshot, cowing the fs
4728 * tree may use more space than it frees. so we need
4729 * reserve extra space.
4730 */
4731 *bytes_to_reserve += rc->nodes_relocated;
4732 }
4733
4734 /*
4735 * called after snapshot is created. migrate block reservation
4736 * and create reloc root for the newly created snapshot
4737 */
4738 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4739 struct btrfs_pending_snapshot *pending)
4740 {
4741 struct btrfs_root *root = pending->root;
4742 struct btrfs_root *reloc_root;
4743 struct btrfs_root *new_root;
4744 struct reloc_control *rc = root->fs_info->reloc_ctl;
4745 int ret;
4746
4747 if (!root->reloc_root || !rc)
4748 return 0;
4749
4750 rc = root->fs_info->reloc_ctl;
4751 rc->merging_rsv_size += rc->nodes_relocated;
4752
4753 if (rc->merge_reloc_tree) {
4754 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4755 rc->block_rsv,
4756 rc->nodes_relocated, true);
4757 if (ret)
4758 return ret;
4759 }
4760
4761 new_root = pending->snap;
4762 reloc_root = create_reloc_root(trans, root->reloc_root,
4763 new_root->root_key.objectid);
4764 if (IS_ERR(reloc_root))
4765 return PTR_ERR(reloc_root);
4766
4767 ret = __add_reloc_root(reloc_root);
4768 BUG_ON(ret < 0);
4769 new_root->reloc_root = reloc_root;
4770
4771 if (rc->create_reloc_tree)
4772 ret = clone_backref_node(trans, rc, root, reloc_root);
4773 return ret;
4774 }
Linux with added FPC-III support