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1 /*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33 #include "inode-map.h"
34 #include "qgroup.h"
35 #include "print-tree.h"
36
37 /*
38 * backref_node, mapping_node and tree_block start with this
39 */
40 struct tree_entry {
41 struct rb_node rb_node;
42 u64 bytenr;
43 };
44
45 /*
46 * present a tree block in the backref cache
47 */
48 struct backref_node {
49 struct rb_node rb_node;
50 u64 bytenr;
51
52 u64 new_bytenr;
53 /* objectid of tree block owner, can be not uptodate */
54 u64 owner;
55 /* link to pending, changed or detached list */
56 struct list_head list;
57 /* list of upper level blocks reference this block */
58 struct list_head upper;
59 /* list of child blocks in the cache */
60 struct list_head lower;
61 /* NULL if this node is not tree root */
62 struct btrfs_root *root;
63 /* extent buffer got by COW the block */
64 struct extent_buffer *eb;
65 /* level of tree block */
66 unsigned int level:8;
67 /* is the block in non-reference counted tree */
68 unsigned int cowonly:1;
69 /* 1 if no child node in the cache */
70 unsigned int lowest:1;
71 /* is the extent buffer locked */
72 unsigned int locked:1;
73 /* has the block been processed */
74 unsigned int processed:1;
75 /* have backrefs of this block been checked */
76 unsigned int checked:1;
77 /*
78 * 1 if corresponding block has been cowed but some upper
79 * level block pointers may not point to the new location
80 */
81 unsigned int pending:1;
82 /*
83 * 1 if the backref node isn't connected to any other
84 * backref node.
85 */
86 unsigned int detached:1;
87 };
88
89 /*
90 * present a block pointer in the backref cache
91 */
92 struct backref_edge {
93 struct list_head list[2];
94 struct backref_node *node[2];
95 };
96
97 #define LOWER 0
98 #define UPPER 1
99 #define RELOCATION_RESERVED_NODES 256
100
101 struct backref_cache {
102 /* red black tree of all backref nodes in the cache */
103 struct rb_root rb_root;
104 /* for passing backref nodes to btrfs_reloc_cow_block */
105 struct backref_node *path[BTRFS_MAX_LEVEL];
106 /*
107 * list of blocks that have been cowed but some block
108 * pointers in upper level blocks may not reflect the
109 * new location
110 */
111 struct list_head pending[BTRFS_MAX_LEVEL];
112 /* list of backref nodes with no child node */
113 struct list_head leaves;
114 /* list of blocks that have been cowed in current transaction */
115 struct list_head changed;
116 /* list of detached backref node. */
117 struct list_head detached;
118
119 u64 last_trans;
120
121 int nr_nodes;
122 int nr_edges;
123 };
124
125 /*
126 * map address of tree root to tree
127 */
128 struct mapping_node {
129 struct rb_node rb_node;
130 u64 bytenr;
131 void *data;
132 };
133
134 struct mapping_tree {
135 struct rb_root rb_root;
136 spinlock_t lock;
137 };
138
139 /*
140 * present a tree block to process
141 */
142 struct tree_block {
143 struct rb_node rb_node;
144 u64 bytenr;
145 struct btrfs_key key;
146 unsigned int level:8;
147 unsigned int key_ready:1;
148 };
149
150 #define MAX_EXTENTS 128
151
152 struct file_extent_cluster {
153 u64 start;
154 u64 end;
155 u64 boundary[MAX_EXTENTS];
156 unsigned int nr;
157 };
158
159 struct reloc_control {
160 /* block group to relocate */
161 struct btrfs_block_group_cache *block_group;
162 /* extent tree */
163 struct btrfs_root *extent_root;
164 /* inode for moving data */
165 struct inode *data_inode;
166
167 struct btrfs_block_rsv *block_rsv;
168
169 struct backref_cache backref_cache;
170
171 struct file_extent_cluster cluster;
172 /* tree blocks have been processed */
173 struct extent_io_tree processed_blocks;
174 /* map start of tree root to corresponding reloc tree */
175 struct mapping_tree reloc_root_tree;
176 /* list of reloc trees */
177 struct list_head reloc_roots;
178 /* size of metadata reservation for merging reloc trees */
179 u64 merging_rsv_size;
180 /* size of relocated tree nodes */
181 u64 nodes_relocated;
182 /* reserved size for block group relocation*/
183 u64 reserved_bytes;
184
185 u64 search_start;
186 u64 extents_found;
187
188 unsigned int stage:8;
189 unsigned int create_reloc_tree:1;
190 unsigned int merge_reloc_tree:1;
191 unsigned int found_file_extent:1;
192 };
193
194 /* stages of data relocation */
195 #define MOVE_DATA_EXTENTS 0
196 #define UPDATE_DATA_PTRS 1
197
198 static void remove_backref_node(struct backref_cache *cache,
199 struct backref_node *node);
200 static void __mark_block_processed(struct reloc_control *rc,
201 struct backref_node *node);
202
203 static void mapping_tree_init(struct mapping_tree *tree)
204 {
205 tree->rb_root = RB_ROOT;
206 spin_lock_init(&tree->lock);
207 }
208
209 static void backref_cache_init(struct backref_cache *cache)
210 {
211 int i;
212 cache->rb_root = RB_ROOT;
213 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
214 INIT_LIST_HEAD(&cache->pending[i]);
215 INIT_LIST_HEAD(&cache->changed);
216 INIT_LIST_HEAD(&cache->detached);
217 INIT_LIST_HEAD(&cache->leaves);
218 }
219
220 static void backref_cache_cleanup(struct backref_cache *cache)
221 {
222 struct backref_node *node;
223 int i;
224
225 while (!list_empty(&cache->detached)) {
226 node = list_entry(cache->detached.next,
227 struct backref_node, list);
228 remove_backref_node(cache, node);
229 }
230
231 while (!list_empty(&cache->leaves)) {
232 node = list_entry(cache->leaves.next,
233 struct backref_node, lower);
234 remove_backref_node(cache, node);
235 }
236
237 cache->last_trans = 0;
238
239 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
240 ASSERT(list_empty(&cache->pending[i]));
241 ASSERT(list_empty(&cache->changed));
242 ASSERT(list_empty(&cache->detached));
243 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
244 ASSERT(!cache->nr_nodes);
245 ASSERT(!cache->nr_edges);
246 }
247
248 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
249 {
250 struct backref_node *node;
251
252 node = kzalloc(sizeof(*node), GFP_NOFS);
253 if (node) {
254 INIT_LIST_HEAD(&node->list);
255 INIT_LIST_HEAD(&node->upper);
256 INIT_LIST_HEAD(&node->lower);
257 RB_CLEAR_NODE(&node->rb_node);
258 cache->nr_nodes++;
259 }
260 return node;
261 }
262
263 static void free_backref_node(struct backref_cache *cache,
264 struct backref_node *node)
265 {
266 if (node) {
267 cache->nr_nodes--;
268 kfree(node);
269 }
270 }
271
272 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
273 {
274 struct backref_edge *edge;
275
276 edge = kzalloc(sizeof(*edge), GFP_NOFS);
277 if (edge)
278 cache->nr_edges++;
279 return edge;
280 }
281
282 static void free_backref_edge(struct backref_cache *cache,
283 struct backref_edge *edge)
284 {
285 if (edge) {
286 cache->nr_edges--;
287 kfree(edge);
288 }
289 }
290
291 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
292 struct rb_node *node)
293 {
294 struct rb_node **p = &root->rb_node;
295 struct rb_node *parent = NULL;
296 struct tree_entry *entry;
297
298 while (*p) {
299 parent = *p;
300 entry = rb_entry(parent, struct tree_entry, rb_node);
301
302 if (bytenr < entry->bytenr)
303 p = &(*p)->rb_left;
304 else if (bytenr > entry->bytenr)
305 p = &(*p)->rb_right;
306 else
307 return parent;
308 }
309
310 rb_link_node(node, parent, p);
311 rb_insert_color(node, root);
312 return NULL;
313 }
314
315 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
316 {
317 struct rb_node *n = root->rb_node;
318 struct tree_entry *entry;
319
320 while (n) {
321 entry = rb_entry(n, struct tree_entry, rb_node);
322
323 if (bytenr < entry->bytenr)
324 n = n->rb_left;
325 else if (bytenr > entry->bytenr)
326 n = n->rb_right;
327 else
328 return n;
329 }
330 return NULL;
331 }
332
333 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
334 {
335
336 struct btrfs_fs_info *fs_info = NULL;
337 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
338 rb_node);
339 if (bnode->root)
340 fs_info = bnode->root->fs_info;
341 btrfs_panic(fs_info, errno,
342 "Inconsistency in backref cache found at offset %llu",
343 bytenr);
344 }
345
346 /*
347 * walk up backref nodes until reach node presents tree root
348 */
349 static struct backref_node *walk_up_backref(struct backref_node *node,
350 struct backref_edge *edges[],
351 int *index)
352 {
353 struct backref_edge *edge;
354 int idx = *index;
355
356 while (!list_empty(&node->upper)) {
357 edge = list_entry(node->upper.next,
358 struct backref_edge, list[LOWER]);
359 edges[idx++] = edge;
360 node = edge->node[UPPER];
361 }
362 BUG_ON(node->detached);
363 *index = idx;
364 return node;
365 }
366
367 /*
368 * walk down backref nodes to find start of next reference path
369 */
370 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
371 int *index)
372 {
373 struct backref_edge *edge;
374 struct backref_node *lower;
375 int idx = *index;
376
377 while (idx > 0) {
378 edge = edges[idx - 1];
379 lower = edge->node[LOWER];
380 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
381 idx--;
382 continue;
383 }
384 edge = list_entry(edge->list[LOWER].next,
385 struct backref_edge, list[LOWER]);
386 edges[idx - 1] = edge;
387 *index = idx;
388 return edge->node[UPPER];
389 }
390 *index = 0;
391 return NULL;
392 }
393
394 static void unlock_node_buffer(struct backref_node *node)
395 {
396 if (node->locked) {
397 btrfs_tree_unlock(node->eb);
398 node->locked = 0;
399 }
400 }
401
402 static void drop_node_buffer(struct backref_node *node)
403 {
404 if (node->eb) {
405 unlock_node_buffer(node);
406 free_extent_buffer(node->eb);
407 node->eb = NULL;
408 }
409 }
410
411 static void drop_backref_node(struct backref_cache *tree,
412 struct backref_node *node)
413 {
414 BUG_ON(!list_empty(&node->upper));
415
416 drop_node_buffer(node);
417 list_del(&node->list);
418 list_del(&node->lower);
419 if (!RB_EMPTY_NODE(&node->rb_node))
420 rb_erase(&node->rb_node, &tree->rb_root);
421 free_backref_node(tree, node);
422 }
423
424 /*
425 * remove a backref node from the backref cache
426 */
427 static void remove_backref_node(struct backref_cache *cache,
428 struct backref_node *node)
429 {
430 struct backref_node *upper;
431 struct backref_edge *edge;
432
433 if (!node)
434 return;
435
436 BUG_ON(!node->lowest && !node->detached);
437 while (!list_empty(&node->upper)) {
438 edge = list_entry(node->upper.next, struct backref_edge,
439 list[LOWER]);
440 upper = edge->node[UPPER];
441 list_del(&edge->list[LOWER]);
442 list_del(&edge->list[UPPER]);
443 free_backref_edge(cache, edge);
444
445 if (RB_EMPTY_NODE(&upper->rb_node)) {
446 BUG_ON(!list_empty(&node->upper));
447 drop_backref_node(cache, node);
448 node = upper;
449 node->lowest = 1;
450 continue;
451 }
452 /*
453 * add the node to leaf node list if no other
454 * child block cached.
455 */
456 if (list_empty(&upper->lower)) {
457 list_add_tail(&upper->lower, &cache->leaves);
458 upper->lowest = 1;
459 }
460 }
461
462 drop_backref_node(cache, node);
463 }
464
465 static void update_backref_node(struct backref_cache *cache,
466 struct backref_node *node, u64 bytenr)
467 {
468 struct rb_node *rb_node;
469 rb_erase(&node->rb_node, &cache->rb_root);
470 node->bytenr = bytenr;
471 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
472 if (rb_node)
473 backref_tree_panic(rb_node, -EEXIST, bytenr);
474 }
475
476 /*
477 * update backref cache after a transaction commit
478 */
479 static int update_backref_cache(struct btrfs_trans_handle *trans,
480 struct backref_cache *cache)
481 {
482 struct backref_node *node;
483 int level = 0;
484
485 if (cache->last_trans == 0) {
486 cache->last_trans = trans->transid;
487 return 0;
488 }
489
490 if (cache->last_trans == trans->transid)
491 return 0;
492
493 /*
494 * detached nodes are used to avoid unnecessary backref
495 * lookup. transaction commit changes the extent tree.
496 * so the detached nodes are no longer useful.
497 */
498 while (!list_empty(&cache->detached)) {
499 node = list_entry(cache->detached.next,
500 struct backref_node, list);
501 remove_backref_node(cache, node);
502 }
503
504 while (!list_empty(&cache->changed)) {
505 node = list_entry(cache->changed.next,
506 struct backref_node, list);
507 list_del_init(&node->list);
508 BUG_ON(node->pending);
509 update_backref_node(cache, node, node->new_bytenr);
510 }
511
512 /*
513 * some nodes can be left in the pending list if there were
514 * errors during processing the pending nodes.
515 */
516 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
517 list_for_each_entry(node, &cache->pending[level], list) {
518 BUG_ON(!node->pending);
519 if (node->bytenr == node->new_bytenr)
520 continue;
521 update_backref_node(cache, node, node->new_bytenr);
522 }
523 }
524
525 cache->last_trans = 0;
526 return 1;
527 }
528
529
530 static int should_ignore_root(struct btrfs_root *root)
531 {
532 struct btrfs_root *reloc_root;
533
534 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
535 return 0;
536
537 reloc_root = root->reloc_root;
538 if (!reloc_root)
539 return 0;
540
541 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
542 root->fs_info->running_transaction->transid - 1)
543 return 0;
544 /*
545 * if there is reloc tree and it was created in previous
546 * transaction backref lookup can find the reloc tree,
547 * so backref node for the fs tree root is useless for
548 * relocation.
549 */
550 return 1;
551 }
552 /*
553 * find reloc tree by address of tree root
554 */
555 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
556 u64 bytenr)
557 {
558 struct rb_node *rb_node;
559 struct mapping_node *node;
560 struct btrfs_root *root = NULL;
561
562 spin_lock(&rc->reloc_root_tree.lock);
563 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
564 if (rb_node) {
565 node = rb_entry(rb_node, struct mapping_node, rb_node);
566 root = (struct btrfs_root *)node->data;
567 }
568 spin_unlock(&rc->reloc_root_tree.lock);
569 return root;
570 }
571
572 static int is_cowonly_root(u64 root_objectid)
573 {
574 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
575 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
576 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
577 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
578 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
579 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
580 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
581 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
582 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
583 return 1;
584 return 0;
585 }
586
587 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
588 u64 root_objectid)
589 {
590 struct btrfs_key key;
591
592 key.objectid = root_objectid;
593 key.type = BTRFS_ROOT_ITEM_KEY;
594 if (is_cowonly_root(root_objectid))
595 key.offset = 0;
596 else
597 key.offset = (u64)-1;
598
599 return btrfs_get_fs_root(fs_info, &key, false);
600 }
601
602 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
603 static noinline_for_stack
604 struct btrfs_root *find_tree_root(struct reloc_control *rc,
605 struct extent_buffer *leaf,
606 struct btrfs_extent_ref_v0 *ref0)
607 {
608 struct btrfs_root *root;
609 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
610 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
611
612 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
613
614 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
615 BUG_ON(IS_ERR(root));
616
617 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
618 generation != btrfs_root_generation(&root->root_item))
619 return NULL;
620
621 return root;
622 }
623 #endif
624
625 static noinline_for_stack
626 int find_inline_backref(struct extent_buffer *leaf, int slot,
627 unsigned long *ptr, unsigned long *end)
628 {
629 struct btrfs_key key;
630 struct btrfs_extent_item *ei;
631 struct btrfs_tree_block_info *bi;
632 u32 item_size;
633
634 btrfs_item_key_to_cpu(leaf, &key, slot);
635
636 item_size = btrfs_item_size_nr(leaf, slot);
637 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
638 if (item_size < sizeof(*ei)) {
639 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
640 return 1;
641 }
642 #endif
643 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
644 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
645 BTRFS_EXTENT_FLAG_TREE_BLOCK));
646
647 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
648 item_size <= sizeof(*ei) + sizeof(*bi)) {
649 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
650 return 1;
651 }
652 if (key.type == BTRFS_METADATA_ITEM_KEY &&
653 item_size <= sizeof(*ei)) {
654 WARN_ON(item_size < sizeof(*ei));
655 return 1;
656 }
657
658 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
659 bi = (struct btrfs_tree_block_info *)(ei + 1);
660 *ptr = (unsigned long)(bi + 1);
661 } else {
662 *ptr = (unsigned long)(ei + 1);
663 }
664 *end = (unsigned long)ei + item_size;
665 return 0;
666 }
667
668 /*
669 * build backref tree for a given tree block. root of the backref tree
670 * corresponds the tree block, leaves of the backref tree correspond
671 * roots of b-trees that reference the tree block.
672 *
673 * the basic idea of this function is check backrefs of a given block
674 * to find upper level blocks that reference the block, and then check
675 * backrefs of these upper level blocks recursively. the recursion stop
676 * when tree root is reached or backrefs for the block is cached.
677 *
678 * NOTE: if we find backrefs for a block are cached, we know backrefs
679 * for all upper level blocks that directly/indirectly reference the
680 * block are also cached.
681 */
682 static noinline_for_stack
683 struct backref_node *build_backref_tree(struct reloc_control *rc,
684 struct btrfs_key *node_key,
685 int level, u64 bytenr)
686 {
687 struct backref_cache *cache = &rc->backref_cache;
688 struct btrfs_path *path1;
689 struct btrfs_path *path2;
690 struct extent_buffer *eb;
691 struct btrfs_root *root;
692 struct backref_node *cur;
693 struct backref_node *upper;
694 struct backref_node *lower;
695 struct backref_node *node = NULL;
696 struct backref_node *exist = NULL;
697 struct backref_edge *edge;
698 struct rb_node *rb_node;
699 struct btrfs_key key;
700 unsigned long end;
701 unsigned long ptr;
702 LIST_HEAD(list);
703 LIST_HEAD(useless);
704 int cowonly;
705 int ret;
706 int err = 0;
707 bool need_check = true;
708
709 path1 = btrfs_alloc_path();
710 path2 = btrfs_alloc_path();
711 if (!path1 || !path2) {
712 err = -ENOMEM;
713 goto out;
714 }
715 path1->reada = READA_FORWARD;
716 path2->reada = READA_FORWARD;
717
718 node = alloc_backref_node(cache);
719 if (!node) {
720 err = -ENOMEM;
721 goto out;
722 }
723
724 node->bytenr = bytenr;
725 node->level = level;
726 node->lowest = 1;
727 cur = node;
728 again:
729 end = 0;
730 ptr = 0;
731 key.objectid = cur->bytenr;
732 key.type = BTRFS_METADATA_ITEM_KEY;
733 key.offset = (u64)-1;
734
735 path1->search_commit_root = 1;
736 path1->skip_locking = 1;
737 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
738 0, 0);
739 if (ret < 0) {
740 err = ret;
741 goto out;
742 }
743 ASSERT(ret);
744 ASSERT(path1->slots[0]);
745
746 path1->slots[0]--;
747
748 WARN_ON(cur->checked);
749 if (!list_empty(&cur->upper)) {
750 /*
751 * the backref was added previously when processing
752 * backref of type BTRFS_TREE_BLOCK_REF_KEY
753 */
754 ASSERT(list_is_singular(&cur->upper));
755 edge = list_entry(cur->upper.next, struct backref_edge,
756 list[LOWER]);
757 ASSERT(list_empty(&edge->list[UPPER]));
758 exist = edge->node[UPPER];
759 /*
760 * add the upper level block to pending list if we need
761 * check its backrefs
762 */
763 if (!exist->checked)
764 list_add_tail(&edge->list[UPPER], &list);
765 } else {
766 exist = NULL;
767 }
768
769 while (1) {
770 cond_resched();
771 eb = path1->nodes[0];
772
773 if (ptr >= end) {
774 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
775 ret = btrfs_next_leaf(rc->extent_root, path1);
776 if (ret < 0) {
777 err = ret;
778 goto out;
779 }
780 if (ret > 0)
781 break;
782 eb = path1->nodes[0];
783 }
784
785 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
786 if (key.objectid != cur->bytenr) {
787 WARN_ON(exist);
788 break;
789 }
790
791 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
792 key.type == BTRFS_METADATA_ITEM_KEY) {
793 ret = find_inline_backref(eb, path1->slots[0],
794 &ptr, &end);
795 if (ret)
796 goto next;
797 }
798 }
799
800 if (ptr < end) {
801 /* update key for inline back ref */
802 struct btrfs_extent_inline_ref *iref;
803 int type;
804 iref = (struct btrfs_extent_inline_ref *)ptr;
805 type = btrfs_get_extent_inline_ref_type(eb, iref,
806 BTRFS_REF_TYPE_BLOCK);
807 if (type == BTRFS_REF_TYPE_INVALID) {
808 err = -EINVAL;
809 goto out;
810 }
811 key.type = type;
812 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
813
814 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
815 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
816 }
817
818 if (exist &&
819 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
820 exist->owner == key.offset) ||
821 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
822 exist->bytenr == key.offset))) {
823 exist = NULL;
824 goto next;
825 }
826
827 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
828 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
829 key.type == BTRFS_EXTENT_REF_V0_KEY) {
830 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
831 struct btrfs_extent_ref_v0 *ref0;
832 ref0 = btrfs_item_ptr(eb, path1->slots[0],
833 struct btrfs_extent_ref_v0);
834 if (key.objectid == key.offset) {
835 root = find_tree_root(rc, eb, ref0);
836 if (root && !should_ignore_root(root))
837 cur->root = root;
838 else
839 list_add(&cur->list, &useless);
840 break;
841 }
842 if (is_cowonly_root(btrfs_ref_root_v0(eb,
843 ref0)))
844 cur->cowonly = 1;
845 }
846 #else
847 ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
848 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
849 #endif
850 if (key.objectid == key.offset) {
851 /*
852 * only root blocks of reloc trees use
853 * backref of this type.
854 */
855 root = find_reloc_root(rc, cur->bytenr);
856 ASSERT(root);
857 cur->root = root;
858 break;
859 }
860
861 edge = alloc_backref_edge(cache);
862 if (!edge) {
863 err = -ENOMEM;
864 goto out;
865 }
866 rb_node = tree_search(&cache->rb_root, key.offset);
867 if (!rb_node) {
868 upper = alloc_backref_node(cache);
869 if (!upper) {
870 free_backref_edge(cache, edge);
871 err = -ENOMEM;
872 goto out;
873 }
874 upper->bytenr = key.offset;
875 upper->level = cur->level + 1;
876 /*
877 * backrefs for the upper level block isn't
878 * cached, add the block to pending list
879 */
880 list_add_tail(&edge->list[UPPER], &list);
881 } else {
882 upper = rb_entry(rb_node, struct backref_node,
883 rb_node);
884 ASSERT(upper->checked);
885 INIT_LIST_HEAD(&edge->list[UPPER]);
886 }
887 list_add_tail(&edge->list[LOWER], &cur->upper);
888 edge->node[LOWER] = cur;
889 edge->node[UPPER] = upper;
890
891 goto next;
892 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
893 goto next;
894 }
895
896 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
897 root = read_fs_root(rc->extent_root->fs_info, key.offset);
898 if (IS_ERR(root)) {
899 err = PTR_ERR(root);
900 goto out;
901 }
902
903 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
904 cur->cowonly = 1;
905
906 if (btrfs_root_level(&root->root_item) == cur->level) {
907 /* tree root */
908 ASSERT(btrfs_root_bytenr(&root->root_item) ==
909 cur->bytenr);
910 if (should_ignore_root(root))
911 list_add(&cur->list, &useless);
912 else
913 cur->root = root;
914 break;
915 }
916
917 level = cur->level + 1;
918
919 /*
920 * searching the tree to find upper level blocks
921 * reference the block.
922 */
923 path2->search_commit_root = 1;
924 path2->skip_locking = 1;
925 path2->lowest_level = level;
926 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
927 path2->lowest_level = 0;
928 if (ret < 0) {
929 err = ret;
930 goto out;
931 }
932 if (ret > 0 && path2->slots[level] > 0)
933 path2->slots[level]--;
934
935 eb = path2->nodes[level];
936 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
937 cur->bytenr) {
938 btrfs_err(root->fs_info,
939 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
940 cur->bytenr, level - 1, root->objectid,
941 node_key->objectid, node_key->type,
942 node_key->offset);
943 err = -ENOENT;
944 goto out;
945 }
946 lower = cur;
947 need_check = true;
948 for (; level < BTRFS_MAX_LEVEL; level++) {
949 if (!path2->nodes[level]) {
950 ASSERT(btrfs_root_bytenr(&root->root_item) ==
951 lower->bytenr);
952 if (should_ignore_root(root))
953 list_add(&lower->list, &useless);
954 else
955 lower->root = root;
956 break;
957 }
958
959 edge = alloc_backref_edge(cache);
960 if (!edge) {
961 err = -ENOMEM;
962 goto out;
963 }
964
965 eb = path2->nodes[level];
966 rb_node = tree_search(&cache->rb_root, eb->start);
967 if (!rb_node) {
968 upper = alloc_backref_node(cache);
969 if (!upper) {
970 free_backref_edge(cache, edge);
971 err = -ENOMEM;
972 goto out;
973 }
974 upper->bytenr = eb->start;
975 upper->owner = btrfs_header_owner(eb);
976 upper->level = lower->level + 1;
977 if (!test_bit(BTRFS_ROOT_REF_COWS,
978 &root->state))
979 upper->cowonly = 1;
980
981 /*
982 * if we know the block isn't shared
983 * we can void checking its backrefs.
984 */
985 if (btrfs_block_can_be_shared(root, eb))
986 upper->checked = 0;
987 else
988 upper->checked = 1;
989
990 /*
991 * add the block to pending list if we
992 * need check its backrefs, we only do this once
993 * while walking up a tree as we will catch
994 * anything else later on.
995 */
996 if (!upper->checked && need_check) {
997 need_check = false;
998 list_add_tail(&edge->list[UPPER],
999 &list);
1000 } else {
1001 if (upper->checked)
1002 need_check = true;
1003 INIT_LIST_HEAD(&edge->list[UPPER]);
1004 }
1005 } else {
1006 upper = rb_entry(rb_node, struct backref_node,
1007 rb_node);
1008 ASSERT(upper->checked);
1009 INIT_LIST_HEAD(&edge->list[UPPER]);
1010 if (!upper->owner)
1011 upper->owner = btrfs_header_owner(eb);
1012 }
1013 list_add_tail(&edge->list[LOWER], &lower->upper);
1014 edge->node[LOWER] = lower;
1015 edge->node[UPPER] = upper;
1016
1017 if (rb_node)
1018 break;
1019 lower = upper;
1020 upper = NULL;
1021 }
1022 btrfs_release_path(path2);
1023 next:
1024 if (ptr < end) {
1025 ptr += btrfs_extent_inline_ref_size(key.type);
1026 if (ptr >= end) {
1027 WARN_ON(ptr > end);
1028 ptr = 0;
1029 end = 0;
1030 }
1031 }
1032 if (ptr >= end)
1033 path1->slots[0]++;
1034 }
1035 btrfs_release_path(path1);
1036
1037 cur->checked = 1;
1038 WARN_ON(exist);
1039
1040 /* the pending list isn't empty, take the first block to process */
1041 if (!list_empty(&list)) {
1042 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1043 list_del_init(&edge->list[UPPER]);
1044 cur = edge->node[UPPER];
1045 goto again;
1046 }
1047
1048 /*
1049 * everything goes well, connect backref nodes and insert backref nodes
1050 * into the cache.
1051 */
1052 ASSERT(node->checked);
1053 cowonly = node->cowonly;
1054 if (!cowonly) {
1055 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1056 &node->rb_node);
1057 if (rb_node)
1058 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1059 list_add_tail(&node->lower, &cache->leaves);
1060 }
1061
1062 list_for_each_entry(edge, &node->upper, list[LOWER])
1063 list_add_tail(&edge->list[UPPER], &list);
1064
1065 while (!list_empty(&list)) {
1066 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1067 list_del_init(&edge->list[UPPER]);
1068 upper = edge->node[UPPER];
1069 if (upper->detached) {
1070 list_del(&edge->list[LOWER]);
1071 lower = edge->node[LOWER];
1072 free_backref_edge(cache, edge);
1073 if (list_empty(&lower->upper))
1074 list_add(&lower->list, &useless);
1075 continue;
1076 }
1077
1078 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1079 if (upper->lowest) {
1080 list_del_init(&upper->lower);
1081 upper->lowest = 0;
1082 }
1083
1084 list_add_tail(&edge->list[UPPER], &upper->lower);
1085 continue;
1086 }
1087
1088 if (!upper->checked) {
1089 /*
1090 * Still want to blow up for developers since this is a
1091 * logic bug.
1092 */
1093 ASSERT(0);
1094 err = -EINVAL;
1095 goto out;
1096 }
1097 if (cowonly != upper->cowonly) {
1098 ASSERT(0);
1099 err = -EINVAL;
1100 goto out;
1101 }
1102
1103 if (!cowonly) {
1104 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1105 &upper->rb_node);
1106 if (rb_node)
1107 backref_tree_panic(rb_node, -EEXIST,
1108 upper->bytenr);
1109 }
1110
1111 list_add_tail(&edge->list[UPPER], &upper->lower);
1112
1113 list_for_each_entry(edge, &upper->upper, list[LOWER])
1114 list_add_tail(&edge->list[UPPER], &list);
1115 }
1116 /*
1117 * process useless backref nodes. backref nodes for tree leaves
1118 * are deleted from the cache. backref nodes for upper level
1119 * tree blocks are left in the cache to avoid unnecessary backref
1120 * lookup.
1121 */
1122 while (!list_empty(&useless)) {
1123 upper = list_entry(useless.next, struct backref_node, list);
1124 list_del_init(&upper->list);
1125 ASSERT(list_empty(&upper->upper));
1126 if (upper == node)
1127 node = NULL;
1128 if (upper->lowest) {
1129 list_del_init(&upper->lower);
1130 upper->lowest = 0;
1131 }
1132 while (!list_empty(&upper->lower)) {
1133 edge = list_entry(upper->lower.next,
1134 struct backref_edge, list[UPPER]);
1135 list_del(&edge->list[UPPER]);
1136 list_del(&edge->list[LOWER]);
1137 lower = edge->node[LOWER];
1138 free_backref_edge(cache, edge);
1139
1140 if (list_empty(&lower->upper))
1141 list_add(&lower->list, &useless);
1142 }
1143 __mark_block_processed(rc, upper);
1144 if (upper->level > 0) {
1145 list_add(&upper->list, &cache->detached);
1146 upper->detached = 1;
1147 } else {
1148 rb_erase(&upper->rb_node, &cache->rb_root);
1149 free_backref_node(cache, upper);
1150 }
1151 }
1152 out:
1153 btrfs_free_path(path1);
1154 btrfs_free_path(path2);
1155 if (err) {
1156 while (!list_empty(&useless)) {
1157 lower = list_entry(useless.next,
1158 struct backref_node, list);
1159 list_del_init(&lower->list);
1160 }
1161 while (!list_empty(&list)) {
1162 edge = list_first_entry(&list, struct backref_edge,
1163 list[UPPER]);
1164 list_del(&edge->list[UPPER]);
1165 list_del(&edge->list[LOWER]);
1166 lower = edge->node[LOWER];
1167 upper = edge->node[UPPER];
1168 free_backref_edge(cache, edge);
1169
1170 /*
1171 * Lower is no longer linked to any upper backref nodes
1172 * and isn't in the cache, we can free it ourselves.
1173 */
1174 if (list_empty(&lower->upper) &&
1175 RB_EMPTY_NODE(&lower->rb_node))
1176 list_add(&lower->list, &useless);
1177
1178 if (!RB_EMPTY_NODE(&upper->rb_node))
1179 continue;
1180
1181 /* Add this guy's upper edges to the list to process */
1182 list_for_each_entry(edge, &upper->upper, list[LOWER])
1183 list_add_tail(&edge->list[UPPER], &list);
1184 if (list_empty(&upper->upper))
1185 list_add(&upper->list, &useless);
1186 }
1187
1188 while (!list_empty(&useless)) {
1189 lower = list_entry(useless.next,
1190 struct backref_node, list);
1191 list_del_init(&lower->list);
1192 if (lower == node)
1193 node = NULL;
1194 free_backref_node(cache, lower);
1195 }
1196
1197 free_backref_node(cache, node);
1198 return ERR_PTR(err);
1199 }
1200 ASSERT(!node || !node->detached);
1201 return node;
1202 }
1203
1204 /*
1205 * helper to add backref node for the newly created snapshot.
1206 * the backref node is created by cloning backref node that
1207 * corresponds to root of source tree
1208 */
1209 static int clone_backref_node(struct btrfs_trans_handle *trans,
1210 struct reloc_control *rc,
1211 struct btrfs_root *src,
1212 struct btrfs_root *dest)
1213 {
1214 struct btrfs_root *reloc_root = src->reloc_root;
1215 struct backref_cache *cache = &rc->backref_cache;
1216 struct backref_node *node = NULL;
1217 struct backref_node *new_node;
1218 struct backref_edge *edge;
1219 struct backref_edge *new_edge;
1220 struct rb_node *rb_node;
1221
1222 if (cache->last_trans > 0)
1223 update_backref_cache(trans, cache);
1224
1225 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1226 if (rb_node) {
1227 node = rb_entry(rb_node, struct backref_node, rb_node);
1228 if (node->detached)
1229 node = NULL;
1230 else
1231 BUG_ON(node->new_bytenr != reloc_root->node->start);
1232 }
1233
1234 if (!node) {
1235 rb_node = tree_search(&cache->rb_root,
1236 reloc_root->commit_root->start);
1237 if (rb_node) {
1238 node = rb_entry(rb_node, struct backref_node,
1239 rb_node);
1240 BUG_ON(node->detached);
1241 }
1242 }
1243
1244 if (!node)
1245 return 0;
1246
1247 new_node = alloc_backref_node(cache);
1248 if (!new_node)
1249 return -ENOMEM;
1250
1251 new_node->bytenr = dest->node->start;
1252 new_node->level = node->level;
1253 new_node->lowest = node->lowest;
1254 new_node->checked = 1;
1255 new_node->root = dest;
1256
1257 if (!node->lowest) {
1258 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1259 new_edge = alloc_backref_edge(cache);
1260 if (!new_edge)
1261 goto fail;
1262
1263 new_edge->node[UPPER] = new_node;
1264 new_edge->node[LOWER] = edge->node[LOWER];
1265 list_add_tail(&new_edge->list[UPPER],
1266 &new_node->lower);
1267 }
1268 } else {
1269 list_add_tail(&new_node->lower, &cache->leaves);
1270 }
1271
1272 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1273 &new_node->rb_node);
1274 if (rb_node)
1275 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1276
1277 if (!new_node->lowest) {
1278 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1279 list_add_tail(&new_edge->list[LOWER],
1280 &new_edge->node[LOWER]->upper);
1281 }
1282 }
1283 return 0;
1284 fail:
1285 while (!list_empty(&new_node->lower)) {
1286 new_edge = list_entry(new_node->lower.next,
1287 struct backref_edge, list[UPPER]);
1288 list_del(&new_edge->list[UPPER]);
1289 free_backref_edge(cache, new_edge);
1290 }
1291 free_backref_node(cache, new_node);
1292 return -ENOMEM;
1293 }
1294
1295 /*
1296 * helper to add 'address of tree root -> reloc tree' mapping
1297 */
1298 static int __must_check __add_reloc_root(struct btrfs_root *root)
1299 {
1300 struct btrfs_fs_info *fs_info = root->fs_info;
1301 struct rb_node *rb_node;
1302 struct mapping_node *node;
1303 struct reloc_control *rc = fs_info->reloc_ctl;
1304
1305 node = kmalloc(sizeof(*node), GFP_NOFS);
1306 if (!node)
1307 return -ENOMEM;
1308
1309 node->bytenr = root->node->start;
1310 node->data = root;
1311
1312 spin_lock(&rc->reloc_root_tree.lock);
1313 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1314 node->bytenr, &node->rb_node);
1315 spin_unlock(&rc->reloc_root_tree.lock);
1316 if (rb_node) {
1317 btrfs_panic(fs_info, -EEXIST,
1318 "Duplicate root found for start=%llu while inserting into relocation tree",
1319 node->bytenr);
1320 }
1321
1322 list_add_tail(&root->root_list, &rc->reloc_roots);
1323 return 0;
1324 }
1325
1326 /*
1327 * helper to delete the 'address of tree root -> reloc tree'
1328 * mapping
1329 */
1330 static void __del_reloc_root(struct btrfs_root *root)
1331 {
1332 struct btrfs_fs_info *fs_info = root->fs_info;
1333 struct rb_node *rb_node;
1334 struct mapping_node *node = NULL;
1335 struct reloc_control *rc = fs_info->reloc_ctl;
1336
1337 spin_lock(&rc->reloc_root_tree.lock);
1338 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1339 root->node->start);
1340 if (rb_node) {
1341 node = rb_entry(rb_node, struct mapping_node, rb_node);
1342 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1343 }
1344 spin_unlock(&rc->reloc_root_tree.lock);
1345
1346 if (!node)
1347 return;
1348 BUG_ON((struct btrfs_root *)node->data != root);
1349
1350 spin_lock(&fs_info->trans_lock);
1351 list_del_init(&root->root_list);
1352 spin_unlock(&fs_info->trans_lock);
1353 kfree(node);
1354 }
1355
1356 /*
1357 * helper to update the 'address of tree root -> reloc tree'
1358 * mapping
1359 */
1360 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1361 {
1362 struct btrfs_fs_info *fs_info = root->fs_info;
1363 struct rb_node *rb_node;
1364 struct mapping_node *node = NULL;
1365 struct reloc_control *rc = fs_info->reloc_ctl;
1366
1367 spin_lock(&rc->reloc_root_tree.lock);
1368 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1369 root->node->start);
1370 if (rb_node) {
1371 node = rb_entry(rb_node, struct mapping_node, rb_node);
1372 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1373 }
1374 spin_unlock(&rc->reloc_root_tree.lock);
1375
1376 if (!node)
1377 return 0;
1378 BUG_ON((struct btrfs_root *)node->data != root);
1379
1380 spin_lock(&rc->reloc_root_tree.lock);
1381 node->bytenr = new_bytenr;
1382 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1383 node->bytenr, &node->rb_node);
1384 spin_unlock(&rc->reloc_root_tree.lock);
1385 if (rb_node)
1386 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1387 return 0;
1388 }
1389
1390 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1391 struct btrfs_root *root, u64 objectid)
1392 {
1393 struct btrfs_fs_info *fs_info = root->fs_info;
1394 struct btrfs_root *reloc_root;
1395 struct extent_buffer *eb;
1396 struct btrfs_root_item *root_item;
1397 struct btrfs_key root_key;
1398 int ret;
1399
1400 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1401 BUG_ON(!root_item);
1402
1403 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1404 root_key.type = BTRFS_ROOT_ITEM_KEY;
1405 root_key.offset = objectid;
1406
1407 if (root->root_key.objectid == objectid) {
1408 u64 commit_root_gen;
1409
1410 /* called by btrfs_init_reloc_root */
1411 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1412 BTRFS_TREE_RELOC_OBJECTID);
1413 BUG_ON(ret);
1414 /*
1415 * Set the last_snapshot field to the generation of the commit
1416 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1417 * correctly (returns true) when the relocation root is created
1418 * either inside the critical section of a transaction commit
1419 * (through transaction.c:qgroup_account_snapshot()) and when
1420 * it's created before the transaction commit is started.
1421 */
1422 commit_root_gen = btrfs_header_generation(root->commit_root);
1423 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1424 } else {
1425 /*
1426 * called by btrfs_reloc_post_snapshot_hook.
1427 * the source tree is a reloc tree, all tree blocks
1428 * modified after it was created have RELOC flag
1429 * set in their headers. so it's OK to not update
1430 * the 'last_snapshot'.
1431 */
1432 ret = btrfs_copy_root(trans, root, root->node, &eb,
1433 BTRFS_TREE_RELOC_OBJECTID);
1434 BUG_ON(ret);
1435 }
1436
1437 memcpy(root_item, &root->root_item, sizeof(*root_item));
1438 btrfs_set_root_bytenr(root_item, eb->start);
1439 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1440 btrfs_set_root_generation(root_item, trans->transid);
1441
1442 if (root->root_key.objectid == objectid) {
1443 btrfs_set_root_refs(root_item, 0);
1444 memset(&root_item->drop_progress, 0,
1445 sizeof(struct btrfs_disk_key));
1446 root_item->drop_level = 0;
1447 }
1448
1449 btrfs_tree_unlock(eb);
1450 free_extent_buffer(eb);
1451
1452 ret = btrfs_insert_root(trans, fs_info->tree_root,
1453 &root_key, root_item);
1454 BUG_ON(ret);
1455 kfree(root_item);
1456
1457 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1458 BUG_ON(IS_ERR(reloc_root));
1459 reloc_root->last_trans = trans->transid;
1460 return reloc_root;
1461 }
1462
1463 /*
1464 * create reloc tree for a given fs tree. reloc tree is just a
1465 * snapshot of the fs tree with special root objectid.
1466 */
1467 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1468 struct btrfs_root *root)
1469 {
1470 struct btrfs_fs_info *fs_info = root->fs_info;
1471 struct btrfs_root *reloc_root;
1472 struct reloc_control *rc = fs_info->reloc_ctl;
1473 struct btrfs_block_rsv *rsv;
1474 int clear_rsv = 0;
1475 int ret;
1476
1477 if (root->reloc_root) {
1478 reloc_root = root->reloc_root;
1479 reloc_root->last_trans = trans->transid;
1480 return 0;
1481 }
1482
1483 if (!rc || !rc->create_reloc_tree ||
1484 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1485 return 0;
1486
1487 if (!trans->reloc_reserved) {
1488 rsv = trans->block_rsv;
1489 trans->block_rsv = rc->block_rsv;
1490 clear_rsv = 1;
1491 }
1492 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1493 if (clear_rsv)
1494 trans->block_rsv = rsv;
1495
1496 ret = __add_reloc_root(reloc_root);
1497 BUG_ON(ret < 0);
1498 root->reloc_root = reloc_root;
1499 return 0;
1500 }
1501
1502 /*
1503 * update root item of reloc tree
1504 */
1505 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1506 struct btrfs_root *root)
1507 {
1508 struct btrfs_fs_info *fs_info = root->fs_info;
1509 struct btrfs_root *reloc_root;
1510 struct btrfs_root_item *root_item;
1511 int ret;
1512
1513 if (!root->reloc_root)
1514 goto out;
1515
1516 reloc_root = root->reloc_root;
1517 root_item = &reloc_root->root_item;
1518
1519 if (fs_info->reloc_ctl->merge_reloc_tree &&
1520 btrfs_root_refs(root_item) == 0) {
1521 root->reloc_root = NULL;
1522 __del_reloc_root(reloc_root);
1523 }
1524
1525 if (reloc_root->commit_root != reloc_root->node) {
1526 btrfs_set_root_node(root_item, reloc_root->node);
1527 free_extent_buffer(reloc_root->commit_root);
1528 reloc_root->commit_root = btrfs_root_node(reloc_root);
1529 }
1530
1531 ret = btrfs_update_root(trans, fs_info->tree_root,
1532 &reloc_root->root_key, root_item);
1533 BUG_ON(ret);
1534
1535 out:
1536 return 0;
1537 }
1538
1539 /*
1540 * helper to find first cached inode with inode number >= objectid
1541 * in a subvolume
1542 */
1543 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1544 {
1545 struct rb_node *node;
1546 struct rb_node *prev;
1547 struct btrfs_inode *entry;
1548 struct inode *inode;
1549
1550 spin_lock(&root->inode_lock);
1551 again:
1552 node = root->inode_tree.rb_node;
1553 prev = NULL;
1554 while (node) {
1555 prev = node;
1556 entry = rb_entry(node, struct btrfs_inode, rb_node);
1557
1558 if (objectid < btrfs_ino(entry))
1559 node = node->rb_left;
1560 else if (objectid > btrfs_ino(entry))
1561 node = node->rb_right;
1562 else
1563 break;
1564 }
1565 if (!node) {
1566 while (prev) {
1567 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1568 if (objectid <= btrfs_ino(entry)) {
1569 node = prev;
1570 break;
1571 }
1572 prev = rb_next(prev);
1573 }
1574 }
1575 while (node) {
1576 entry = rb_entry(node, struct btrfs_inode, rb_node);
1577 inode = igrab(&entry->vfs_inode);
1578 if (inode) {
1579 spin_unlock(&root->inode_lock);
1580 return inode;
1581 }
1582
1583 objectid = btrfs_ino(entry) + 1;
1584 if (cond_resched_lock(&root->inode_lock))
1585 goto again;
1586
1587 node = rb_next(node);
1588 }
1589 spin_unlock(&root->inode_lock);
1590 return NULL;
1591 }
1592
1593 static int in_block_group(u64 bytenr,
1594 struct btrfs_block_group_cache *block_group)
1595 {
1596 if (bytenr >= block_group->key.objectid &&
1597 bytenr < block_group->key.objectid + block_group->key.offset)
1598 return 1;
1599 return 0;
1600 }
1601
1602 /*
1603 * get new location of data
1604 */
1605 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1606 u64 bytenr, u64 num_bytes)
1607 {
1608 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1609 struct btrfs_path *path;
1610 struct btrfs_file_extent_item *fi;
1611 struct extent_buffer *leaf;
1612 int ret;
1613
1614 path = btrfs_alloc_path();
1615 if (!path)
1616 return -ENOMEM;
1617
1618 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1619 ret = btrfs_lookup_file_extent(NULL, root, path,
1620 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1621 if (ret < 0)
1622 goto out;
1623 if (ret > 0) {
1624 ret = -ENOENT;
1625 goto out;
1626 }
1627
1628 leaf = path->nodes[0];
1629 fi = btrfs_item_ptr(leaf, path->slots[0],
1630 struct btrfs_file_extent_item);
1631
1632 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1633 btrfs_file_extent_compression(leaf, fi) ||
1634 btrfs_file_extent_encryption(leaf, fi) ||
1635 btrfs_file_extent_other_encoding(leaf, fi));
1636
1637 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1638 ret = -EINVAL;
1639 goto out;
1640 }
1641
1642 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1643 ret = 0;
1644 out:
1645 btrfs_free_path(path);
1646 return ret;
1647 }
1648
1649 /*
1650 * update file extent items in the tree leaf to point to
1651 * the new locations.
1652 */
1653 static noinline_for_stack
1654 int replace_file_extents(struct btrfs_trans_handle *trans,
1655 struct reloc_control *rc,
1656 struct btrfs_root *root,
1657 struct extent_buffer *leaf)
1658 {
1659 struct btrfs_fs_info *fs_info = root->fs_info;
1660 struct btrfs_key key;
1661 struct btrfs_file_extent_item *fi;
1662 struct inode *inode = NULL;
1663 u64 parent;
1664 u64 bytenr;
1665 u64 new_bytenr = 0;
1666 u64 num_bytes;
1667 u64 end;
1668 u32 nritems;
1669 u32 i;
1670 int ret = 0;
1671 int first = 1;
1672 int dirty = 0;
1673
1674 if (rc->stage != UPDATE_DATA_PTRS)
1675 return 0;
1676
1677 /* reloc trees always use full backref */
1678 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1679 parent = leaf->start;
1680 else
1681 parent = 0;
1682
1683 nritems = btrfs_header_nritems(leaf);
1684 for (i = 0; i < nritems; i++) {
1685 cond_resched();
1686 btrfs_item_key_to_cpu(leaf, &key, i);
1687 if (key.type != BTRFS_EXTENT_DATA_KEY)
1688 continue;
1689 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1690 if (btrfs_file_extent_type(leaf, fi) ==
1691 BTRFS_FILE_EXTENT_INLINE)
1692 continue;
1693 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1694 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1695 if (bytenr == 0)
1696 continue;
1697 if (!in_block_group(bytenr, rc->block_group))
1698 continue;
1699
1700 /*
1701 * if we are modifying block in fs tree, wait for readpage
1702 * to complete and drop the extent cache
1703 */
1704 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1705 if (first) {
1706 inode = find_next_inode(root, key.objectid);
1707 first = 0;
1708 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1709 btrfs_add_delayed_iput(inode);
1710 inode = find_next_inode(root, key.objectid);
1711 }
1712 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1713 end = key.offset +
1714 btrfs_file_extent_num_bytes(leaf, fi);
1715 WARN_ON(!IS_ALIGNED(key.offset,
1716 fs_info->sectorsize));
1717 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1718 end--;
1719 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1720 key.offset, end);
1721 if (!ret)
1722 continue;
1723
1724 btrfs_drop_extent_cache(BTRFS_I(inode),
1725 key.offset, end, 1);
1726 unlock_extent(&BTRFS_I(inode)->io_tree,
1727 key.offset, end);
1728 }
1729 }
1730
1731 ret = get_new_location(rc->data_inode, &new_bytenr,
1732 bytenr, num_bytes);
1733 if (ret) {
1734 /*
1735 * Don't have to abort since we've not changed anything
1736 * in the file extent yet.
1737 */
1738 break;
1739 }
1740
1741 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1742 dirty = 1;
1743
1744 key.offset -= btrfs_file_extent_offset(leaf, fi);
1745 ret = btrfs_inc_extent_ref(trans, fs_info, new_bytenr,
1746 num_bytes, parent,
1747 btrfs_header_owner(leaf),
1748 key.objectid, key.offset);
1749 if (ret) {
1750 btrfs_abort_transaction(trans, ret);
1751 break;
1752 }
1753
1754 ret = btrfs_free_extent(trans, fs_info, bytenr, num_bytes,
1755 parent, btrfs_header_owner(leaf),
1756 key.objectid, key.offset);
1757 if (ret) {
1758 btrfs_abort_transaction(trans, ret);
1759 break;
1760 }
1761 }
1762 if (dirty)
1763 btrfs_mark_buffer_dirty(leaf);
1764 if (inode)
1765 btrfs_add_delayed_iput(inode);
1766 return ret;
1767 }
1768
1769 static noinline_for_stack
1770 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1771 struct btrfs_path *path, int level)
1772 {
1773 struct btrfs_disk_key key1;
1774 struct btrfs_disk_key key2;
1775 btrfs_node_key(eb, &key1, slot);
1776 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1777 return memcmp(&key1, &key2, sizeof(key1));
1778 }
1779
1780 /*
1781 * try to replace tree blocks in fs tree with the new blocks
1782 * in reloc tree. tree blocks haven't been modified since the
1783 * reloc tree was create can be replaced.
1784 *
1785 * if a block was replaced, level of the block + 1 is returned.
1786 * if no block got replaced, 0 is returned. if there are other
1787 * errors, a negative error number is returned.
1788 */
1789 static noinline_for_stack
1790 int replace_path(struct btrfs_trans_handle *trans,
1791 struct btrfs_root *dest, struct btrfs_root *src,
1792 struct btrfs_path *path, struct btrfs_key *next_key,
1793 int lowest_level, int max_level)
1794 {
1795 struct btrfs_fs_info *fs_info = dest->fs_info;
1796 struct extent_buffer *eb;
1797 struct extent_buffer *parent;
1798 struct btrfs_key key;
1799 u64 old_bytenr;
1800 u64 new_bytenr;
1801 u64 old_ptr_gen;
1802 u64 new_ptr_gen;
1803 u64 last_snapshot;
1804 u32 blocksize;
1805 int cow = 0;
1806 int level;
1807 int ret;
1808 int slot;
1809
1810 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1811 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1812
1813 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1814 again:
1815 slot = path->slots[lowest_level];
1816 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1817
1818 eb = btrfs_lock_root_node(dest);
1819 btrfs_set_lock_blocking(eb);
1820 level = btrfs_header_level(eb);
1821
1822 if (level < lowest_level) {
1823 btrfs_tree_unlock(eb);
1824 free_extent_buffer(eb);
1825 return 0;
1826 }
1827
1828 if (cow) {
1829 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1830 BUG_ON(ret);
1831 }
1832 btrfs_set_lock_blocking(eb);
1833
1834 if (next_key) {
1835 next_key->objectid = (u64)-1;
1836 next_key->type = (u8)-1;
1837 next_key->offset = (u64)-1;
1838 }
1839
1840 parent = eb;
1841 while (1) {
1842 level = btrfs_header_level(parent);
1843 BUG_ON(level < lowest_level);
1844
1845 ret = btrfs_bin_search(parent, &key, level, &slot);
1846 if (ret && slot > 0)
1847 slot--;
1848
1849 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1850 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1851
1852 old_bytenr = btrfs_node_blockptr(parent, slot);
1853 blocksize = fs_info->nodesize;
1854 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1855
1856 if (level <= max_level) {
1857 eb = path->nodes[level];
1858 new_bytenr = btrfs_node_blockptr(eb,
1859 path->slots[level]);
1860 new_ptr_gen = btrfs_node_ptr_generation(eb,
1861 path->slots[level]);
1862 } else {
1863 new_bytenr = 0;
1864 new_ptr_gen = 0;
1865 }
1866
1867 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1868 ret = level;
1869 break;
1870 }
1871
1872 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1873 memcmp_node_keys(parent, slot, path, level)) {
1874 if (level <= lowest_level) {
1875 ret = 0;
1876 break;
1877 }
1878
1879 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen);
1880 if (IS_ERR(eb)) {
1881 ret = PTR_ERR(eb);
1882 break;
1883 } else if (!extent_buffer_uptodate(eb)) {
1884 ret = -EIO;
1885 free_extent_buffer(eb);
1886 break;
1887 }
1888 btrfs_tree_lock(eb);
1889 if (cow) {
1890 ret = btrfs_cow_block(trans, dest, eb, parent,
1891 slot, &eb);
1892 BUG_ON(ret);
1893 }
1894 btrfs_set_lock_blocking(eb);
1895
1896 btrfs_tree_unlock(parent);
1897 free_extent_buffer(parent);
1898
1899 parent = eb;
1900 continue;
1901 }
1902
1903 if (!cow) {
1904 btrfs_tree_unlock(parent);
1905 free_extent_buffer(parent);
1906 cow = 1;
1907 goto again;
1908 }
1909
1910 btrfs_node_key_to_cpu(path->nodes[level], &key,
1911 path->slots[level]);
1912 btrfs_release_path(path);
1913
1914 path->lowest_level = level;
1915 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1916 path->lowest_level = 0;
1917 BUG_ON(ret);
1918
1919 /*
1920 * Info qgroup to trace both subtrees.
1921 *
1922 * We must trace both trees.
1923 * 1) Tree reloc subtree
1924 * If not traced, we will leak data numbers
1925 * 2) Fs subtree
1926 * If not traced, we will double count old data
1927 * and tree block numbers, if current trans doesn't free
1928 * data reloc tree inode.
1929 */
1930 ret = btrfs_qgroup_trace_subtree(trans, src, parent,
1931 btrfs_header_generation(parent),
1932 btrfs_header_level(parent));
1933 if (ret < 0)
1934 break;
1935 ret = btrfs_qgroup_trace_subtree(trans, dest,
1936 path->nodes[level],
1937 btrfs_header_generation(path->nodes[level]),
1938 btrfs_header_level(path->nodes[level]));
1939 if (ret < 0)
1940 break;
1941
1942 /*
1943 * swap blocks in fs tree and reloc tree.
1944 */
1945 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1946 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1947 btrfs_mark_buffer_dirty(parent);
1948
1949 btrfs_set_node_blockptr(path->nodes[level],
1950 path->slots[level], old_bytenr);
1951 btrfs_set_node_ptr_generation(path->nodes[level],
1952 path->slots[level], old_ptr_gen);
1953 btrfs_mark_buffer_dirty(path->nodes[level]);
1954
1955 ret = btrfs_inc_extent_ref(trans, fs_info, old_bytenr,
1956 blocksize, path->nodes[level]->start,
1957 src->root_key.objectid, level - 1, 0);
1958 BUG_ON(ret);
1959 ret = btrfs_inc_extent_ref(trans, fs_info, new_bytenr,
1960 blocksize, 0, dest->root_key.objectid,
1961 level - 1, 0);
1962 BUG_ON(ret);
1963
1964 ret = btrfs_free_extent(trans, fs_info, new_bytenr, blocksize,
1965 path->nodes[level]->start,
1966 src->root_key.objectid, level - 1, 0);
1967 BUG_ON(ret);
1968
1969 ret = btrfs_free_extent(trans, fs_info, old_bytenr, blocksize,
1970 0, dest->root_key.objectid, level - 1,
1971 0);
1972 BUG_ON(ret);
1973
1974 btrfs_unlock_up_safe(path, 0);
1975
1976 ret = level;
1977 break;
1978 }
1979 btrfs_tree_unlock(parent);
1980 free_extent_buffer(parent);
1981 return ret;
1982 }
1983
1984 /*
1985 * helper to find next relocated block in reloc tree
1986 */
1987 static noinline_for_stack
1988 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1989 int *level)
1990 {
1991 struct extent_buffer *eb;
1992 int i;
1993 u64 last_snapshot;
1994 u32 nritems;
1995
1996 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1997
1998 for (i = 0; i < *level; i++) {
1999 free_extent_buffer(path->nodes[i]);
2000 path->nodes[i] = NULL;
2001 }
2002
2003 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
2004 eb = path->nodes[i];
2005 nritems = btrfs_header_nritems(eb);
2006 while (path->slots[i] + 1 < nritems) {
2007 path->slots[i]++;
2008 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
2009 last_snapshot)
2010 continue;
2011
2012 *level = i;
2013 return 0;
2014 }
2015 free_extent_buffer(path->nodes[i]);
2016 path->nodes[i] = NULL;
2017 }
2018 return 1;
2019 }
2020
2021 /*
2022 * walk down reloc tree to find relocated block of lowest level
2023 */
2024 static noinline_for_stack
2025 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2026 int *level)
2027 {
2028 struct btrfs_fs_info *fs_info = root->fs_info;
2029 struct extent_buffer *eb = NULL;
2030 int i;
2031 u64 bytenr;
2032 u64 ptr_gen = 0;
2033 u64 last_snapshot;
2034 u32 nritems;
2035
2036 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2037
2038 for (i = *level; i > 0; i--) {
2039 eb = path->nodes[i];
2040 nritems = btrfs_header_nritems(eb);
2041 while (path->slots[i] < nritems) {
2042 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2043 if (ptr_gen > last_snapshot)
2044 break;
2045 path->slots[i]++;
2046 }
2047 if (path->slots[i] >= nritems) {
2048 if (i == *level)
2049 break;
2050 *level = i + 1;
2051 return 0;
2052 }
2053 if (i == 1) {
2054 *level = i;
2055 return 0;
2056 }
2057
2058 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2059 eb = read_tree_block(fs_info, bytenr, ptr_gen);
2060 if (IS_ERR(eb)) {
2061 return PTR_ERR(eb);
2062 } else if (!extent_buffer_uptodate(eb)) {
2063 free_extent_buffer(eb);
2064 return -EIO;
2065 }
2066 BUG_ON(btrfs_header_level(eb) != i - 1);
2067 path->nodes[i - 1] = eb;
2068 path->slots[i - 1] = 0;
2069 }
2070 return 1;
2071 }
2072
2073 /*
2074 * invalidate extent cache for file extents whose key in range of
2075 * [min_key, max_key)
2076 */
2077 static int invalidate_extent_cache(struct btrfs_root *root,
2078 struct btrfs_key *min_key,
2079 struct btrfs_key *max_key)
2080 {
2081 struct btrfs_fs_info *fs_info = root->fs_info;
2082 struct inode *inode = NULL;
2083 u64 objectid;
2084 u64 start, end;
2085 u64 ino;
2086
2087 objectid = min_key->objectid;
2088 while (1) {
2089 cond_resched();
2090 iput(inode);
2091
2092 if (objectid > max_key->objectid)
2093 break;
2094
2095 inode = find_next_inode(root, objectid);
2096 if (!inode)
2097 break;
2098 ino = btrfs_ino(BTRFS_I(inode));
2099
2100 if (ino > max_key->objectid) {
2101 iput(inode);
2102 break;
2103 }
2104
2105 objectid = ino + 1;
2106 if (!S_ISREG(inode->i_mode))
2107 continue;
2108
2109 if (unlikely(min_key->objectid == ino)) {
2110 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2111 continue;
2112 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2113 start = 0;
2114 else {
2115 start = min_key->offset;
2116 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2117 }
2118 } else {
2119 start = 0;
2120 }
2121
2122 if (unlikely(max_key->objectid == ino)) {
2123 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2124 continue;
2125 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2126 end = (u64)-1;
2127 } else {
2128 if (max_key->offset == 0)
2129 continue;
2130 end = max_key->offset;
2131 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2132 end--;
2133 }
2134 } else {
2135 end = (u64)-1;
2136 }
2137
2138 /* the lock_extent waits for readpage to complete */
2139 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2140 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2141 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2142 }
2143 return 0;
2144 }
2145
2146 static int find_next_key(struct btrfs_path *path, int level,
2147 struct btrfs_key *key)
2148
2149 {
2150 while (level < BTRFS_MAX_LEVEL) {
2151 if (!path->nodes[level])
2152 break;
2153 if (path->slots[level] + 1 <
2154 btrfs_header_nritems(path->nodes[level])) {
2155 btrfs_node_key_to_cpu(path->nodes[level], key,
2156 path->slots[level] + 1);
2157 return 0;
2158 }
2159 level++;
2160 }
2161 return 1;
2162 }
2163
2164 /*
2165 * merge the relocated tree blocks in reloc tree with corresponding
2166 * fs tree.
2167 */
2168 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2169 struct btrfs_root *root)
2170 {
2171 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2172 LIST_HEAD(inode_list);
2173 struct btrfs_key key;
2174 struct btrfs_key next_key;
2175 struct btrfs_trans_handle *trans = NULL;
2176 struct btrfs_root *reloc_root;
2177 struct btrfs_root_item *root_item;
2178 struct btrfs_path *path;
2179 struct extent_buffer *leaf;
2180 int level;
2181 int max_level;
2182 int replaced = 0;
2183 int ret;
2184 int err = 0;
2185 u32 min_reserved;
2186
2187 path = btrfs_alloc_path();
2188 if (!path)
2189 return -ENOMEM;
2190 path->reada = READA_FORWARD;
2191
2192 reloc_root = root->reloc_root;
2193 root_item = &reloc_root->root_item;
2194
2195 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2196 level = btrfs_root_level(root_item);
2197 extent_buffer_get(reloc_root->node);
2198 path->nodes[level] = reloc_root->node;
2199 path->slots[level] = 0;
2200 } else {
2201 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2202
2203 level = root_item->drop_level;
2204 BUG_ON(level == 0);
2205 path->lowest_level = level;
2206 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2207 path->lowest_level = 0;
2208 if (ret < 0) {
2209 btrfs_free_path(path);
2210 return ret;
2211 }
2212
2213 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2214 path->slots[level]);
2215 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2216
2217 btrfs_unlock_up_safe(path, 0);
2218 }
2219
2220 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2221 memset(&next_key, 0, sizeof(next_key));
2222
2223 while (1) {
2224 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2225 BTRFS_RESERVE_FLUSH_ALL);
2226 if (ret) {
2227 err = ret;
2228 goto out;
2229 }
2230 trans = btrfs_start_transaction(root, 0);
2231 if (IS_ERR(trans)) {
2232 err = PTR_ERR(trans);
2233 trans = NULL;
2234 goto out;
2235 }
2236 trans->block_rsv = rc->block_rsv;
2237
2238 replaced = 0;
2239 max_level = level;
2240
2241 ret = walk_down_reloc_tree(reloc_root, path, &level);
2242 if (ret < 0) {
2243 err = ret;
2244 goto out;
2245 }
2246 if (ret > 0)
2247 break;
2248
2249 if (!find_next_key(path, level, &key) &&
2250 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2251 ret = 0;
2252 } else {
2253 ret = replace_path(trans, root, reloc_root, path,
2254 &next_key, level, max_level);
2255 }
2256 if (ret < 0) {
2257 err = ret;
2258 goto out;
2259 }
2260
2261 if (ret > 0) {
2262 level = ret;
2263 btrfs_node_key_to_cpu(path->nodes[level], &key,
2264 path->slots[level]);
2265 replaced = 1;
2266 }
2267
2268 ret = walk_up_reloc_tree(reloc_root, path, &level);
2269 if (ret > 0)
2270 break;
2271
2272 BUG_ON(level == 0);
2273 /*
2274 * save the merging progress in the drop_progress.
2275 * this is OK since root refs == 1 in this case.
2276 */
2277 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2278 path->slots[level]);
2279 root_item->drop_level = level;
2280
2281 btrfs_end_transaction_throttle(trans);
2282 trans = NULL;
2283
2284 btrfs_btree_balance_dirty(fs_info);
2285
2286 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2287 invalidate_extent_cache(root, &key, &next_key);
2288 }
2289
2290 /*
2291 * handle the case only one block in the fs tree need to be
2292 * relocated and the block is tree root.
2293 */
2294 leaf = btrfs_lock_root_node(root);
2295 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2296 btrfs_tree_unlock(leaf);
2297 free_extent_buffer(leaf);
2298 if (ret < 0)
2299 err = ret;
2300 out:
2301 btrfs_free_path(path);
2302
2303 if (err == 0) {
2304 memset(&root_item->drop_progress, 0,
2305 sizeof(root_item->drop_progress));
2306 root_item->drop_level = 0;
2307 btrfs_set_root_refs(root_item, 0);
2308 btrfs_update_reloc_root(trans, root);
2309 }
2310
2311 if (trans)
2312 btrfs_end_transaction_throttle(trans);
2313
2314 btrfs_btree_balance_dirty(fs_info);
2315
2316 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2317 invalidate_extent_cache(root, &key, &next_key);
2318
2319 return err;
2320 }
2321
2322 static noinline_for_stack
2323 int prepare_to_merge(struct reloc_control *rc, int err)
2324 {
2325 struct btrfs_root *root = rc->extent_root;
2326 struct btrfs_fs_info *fs_info = root->fs_info;
2327 struct btrfs_root *reloc_root;
2328 struct btrfs_trans_handle *trans;
2329 LIST_HEAD(reloc_roots);
2330 u64 num_bytes = 0;
2331 int ret;
2332
2333 mutex_lock(&fs_info->reloc_mutex);
2334 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2335 rc->merging_rsv_size += rc->nodes_relocated * 2;
2336 mutex_unlock(&fs_info->reloc_mutex);
2337
2338 again:
2339 if (!err) {
2340 num_bytes = rc->merging_rsv_size;
2341 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2342 BTRFS_RESERVE_FLUSH_ALL);
2343 if (ret)
2344 err = ret;
2345 }
2346
2347 trans = btrfs_join_transaction(rc->extent_root);
2348 if (IS_ERR(trans)) {
2349 if (!err)
2350 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2351 num_bytes);
2352 return PTR_ERR(trans);
2353 }
2354
2355 if (!err) {
2356 if (num_bytes != rc->merging_rsv_size) {
2357 btrfs_end_transaction(trans);
2358 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2359 num_bytes);
2360 goto again;
2361 }
2362 }
2363
2364 rc->merge_reloc_tree = 1;
2365
2366 while (!list_empty(&rc->reloc_roots)) {
2367 reloc_root = list_entry(rc->reloc_roots.next,
2368 struct btrfs_root, root_list);
2369 list_del_init(&reloc_root->root_list);
2370
2371 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2372 BUG_ON(IS_ERR(root));
2373 BUG_ON(root->reloc_root != reloc_root);
2374
2375 /*
2376 * set reference count to 1, so btrfs_recover_relocation
2377 * knows it should resumes merging
2378 */
2379 if (!err)
2380 btrfs_set_root_refs(&reloc_root->root_item, 1);
2381 btrfs_update_reloc_root(trans, root);
2382
2383 list_add(&reloc_root->root_list, &reloc_roots);
2384 }
2385
2386 list_splice(&reloc_roots, &rc->reloc_roots);
2387
2388 if (!err)
2389 btrfs_commit_transaction(trans);
2390 else
2391 btrfs_end_transaction(trans);
2392 return err;
2393 }
2394
2395 static noinline_for_stack
2396 void free_reloc_roots(struct list_head *list)
2397 {
2398 struct btrfs_root *reloc_root;
2399
2400 while (!list_empty(list)) {
2401 reloc_root = list_entry(list->next, struct btrfs_root,
2402 root_list);
2403 free_extent_buffer(reloc_root->node);
2404 free_extent_buffer(reloc_root->commit_root);
2405 reloc_root->node = NULL;
2406 reloc_root->commit_root = NULL;
2407 __del_reloc_root(reloc_root);
2408 }
2409 }
2410
2411 static noinline_for_stack
2412 void merge_reloc_roots(struct reloc_control *rc)
2413 {
2414 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2415 struct btrfs_root *root;
2416 struct btrfs_root *reloc_root;
2417 LIST_HEAD(reloc_roots);
2418 int found = 0;
2419 int ret = 0;
2420 again:
2421 root = rc->extent_root;
2422
2423 /*
2424 * this serializes us with btrfs_record_root_in_transaction,
2425 * we have to make sure nobody is in the middle of
2426 * adding their roots to the list while we are
2427 * doing this splice
2428 */
2429 mutex_lock(&fs_info->reloc_mutex);
2430 list_splice_init(&rc->reloc_roots, &reloc_roots);
2431 mutex_unlock(&fs_info->reloc_mutex);
2432
2433 while (!list_empty(&reloc_roots)) {
2434 found = 1;
2435 reloc_root = list_entry(reloc_roots.next,
2436 struct btrfs_root, root_list);
2437
2438 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2439 root = read_fs_root(fs_info,
2440 reloc_root->root_key.offset);
2441 BUG_ON(IS_ERR(root));
2442 BUG_ON(root->reloc_root != reloc_root);
2443
2444 ret = merge_reloc_root(rc, root);
2445 if (ret) {
2446 if (list_empty(&reloc_root->root_list))
2447 list_add_tail(&reloc_root->root_list,
2448 &reloc_roots);
2449 goto out;
2450 }
2451 } else {
2452 list_del_init(&reloc_root->root_list);
2453 }
2454
2455 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2456 if (ret < 0) {
2457 if (list_empty(&reloc_root->root_list))
2458 list_add_tail(&reloc_root->root_list,
2459 &reloc_roots);
2460 goto out;
2461 }
2462 }
2463
2464 if (found) {
2465 found = 0;
2466 goto again;
2467 }
2468 out:
2469 if (ret) {
2470 btrfs_handle_fs_error(fs_info, ret, NULL);
2471 if (!list_empty(&reloc_roots))
2472 free_reloc_roots(&reloc_roots);
2473
2474 /* new reloc root may be added */
2475 mutex_lock(&fs_info->reloc_mutex);
2476 list_splice_init(&rc->reloc_roots, &reloc_roots);
2477 mutex_unlock(&fs_info->reloc_mutex);
2478 if (!list_empty(&reloc_roots))
2479 free_reloc_roots(&reloc_roots);
2480 }
2481
2482 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2483 }
2484
2485 static void free_block_list(struct rb_root *blocks)
2486 {
2487 struct tree_block *block;
2488 struct rb_node *rb_node;
2489 while ((rb_node = rb_first(blocks))) {
2490 block = rb_entry(rb_node, struct tree_block, rb_node);
2491 rb_erase(rb_node, blocks);
2492 kfree(block);
2493 }
2494 }
2495
2496 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2497 struct btrfs_root *reloc_root)
2498 {
2499 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2500 struct btrfs_root *root;
2501
2502 if (reloc_root->last_trans == trans->transid)
2503 return 0;
2504
2505 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2506 BUG_ON(IS_ERR(root));
2507 BUG_ON(root->reloc_root != reloc_root);
2508
2509 return btrfs_record_root_in_trans(trans, root);
2510 }
2511
2512 static noinline_for_stack
2513 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2514 struct reloc_control *rc,
2515 struct backref_node *node,
2516 struct backref_edge *edges[])
2517 {
2518 struct backref_node *next;
2519 struct btrfs_root *root;
2520 int index = 0;
2521
2522 next = node;
2523 while (1) {
2524 cond_resched();
2525 next = walk_up_backref(next, edges, &index);
2526 root = next->root;
2527 BUG_ON(!root);
2528 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2529
2530 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2531 record_reloc_root_in_trans(trans, root);
2532 break;
2533 }
2534
2535 btrfs_record_root_in_trans(trans, root);
2536 root = root->reloc_root;
2537
2538 if (next->new_bytenr != root->node->start) {
2539 BUG_ON(next->new_bytenr);
2540 BUG_ON(!list_empty(&next->list));
2541 next->new_bytenr = root->node->start;
2542 next->root = root;
2543 list_add_tail(&next->list,
2544 &rc->backref_cache.changed);
2545 __mark_block_processed(rc, next);
2546 break;
2547 }
2548
2549 WARN_ON(1);
2550 root = NULL;
2551 next = walk_down_backref(edges, &index);
2552 if (!next || next->level <= node->level)
2553 break;
2554 }
2555 if (!root)
2556 return NULL;
2557
2558 next = node;
2559 /* setup backref node path for btrfs_reloc_cow_block */
2560 while (1) {
2561 rc->backref_cache.path[next->level] = next;
2562 if (--index < 0)
2563 break;
2564 next = edges[index]->node[UPPER];
2565 }
2566 return root;
2567 }
2568
2569 /*
2570 * select a tree root for relocation. return NULL if the block
2571 * is reference counted. we should use do_relocation() in this
2572 * case. return a tree root pointer if the block isn't reference
2573 * counted. return -ENOENT if the block is root of reloc tree.
2574 */
2575 static noinline_for_stack
2576 struct btrfs_root *select_one_root(struct backref_node *node)
2577 {
2578 struct backref_node *next;
2579 struct btrfs_root *root;
2580 struct btrfs_root *fs_root = NULL;
2581 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2582 int index = 0;
2583
2584 next = node;
2585 while (1) {
2586 cond_resched();
2587 next = walk_up_backref(next, edges, &index);
2588 root = next->root;
2589 BUG_ON(!root);
2590
2591 /* no other choice for non-references counted tree */
2592 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2593 return root;
2594
2595 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2596 fs_root = root;
2597
2598 if (next != node)
2599 return NULL;
2600
2601 next = walk_down_backref(edges, &index);
2602 if (!next || next->level <= node->level)
2603 break;
2604 }
2605
2606 if (!fs_root)
2607 return ERR_PTR(-ENOENT);
2608 return fs_root;
2609 }
2610
2611 static noinline_for_stack
2612 u64 calcu_metadata_size(struct reloc_control *rc,
2613 struct backref_node *node, int reserve)
2614 {
2615 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2616 struct backref_node *next = node;
2617 struct backref_edge *edge;
2618 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2619 u64 num_bytes = 0;
2620 int index = 0;
2621
2622 BUG_ON(reserve && node->processed);
2623
2624 while (next) {
2625 cond_resched();
2626 while (1) {
2627 if (next->processed && (reserve || next != node))
2628 break;
2629
2630 num_bytes += fs_info->nodesize;
2631
2632 if (list_empty(&next->upper))
2633 break;
2634
2635 edge = list_entry(next->upper.next,
2636 struct backref_edge, list[LOWER]);
2637 edges[index++] = edge;
2638 next = edge->node[UPPER];
2639 }
2640 next = walk_down_backref(edges, &index);
2641 }
2642 return num_bytes;
2643 }
2644
2645 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2646 struct reloc_control *rc,
2647 struct backref_node *node)
2648 {
2649 struct btrfs_root *root = rc->extent_root;
2650 struct btrfs_fs_info *fs_info = root->fs_info;
2651 u64 num_bytes;
2652 int ret;
2653 u64 tmp;
2654
2655 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2656
2657 trans->block_rsv = rc->block_rsv;
2658 rc->reserved_bytes += num_bytes;
2659
2660 /*
2661 * We are under a transaction here so we can only do limited flushing.
2662 * If we get an enospc just kick back -EAGAIN so we know to drop the
2663 * transaction and try to refill when we can flush all the things.
2664 */
2665 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2666 BTRFS_RESERVE_FLUSH_LIMIT);
2667 if (ret) {
2668 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2669 while (tmp <= rc->reserved_bytes)
2670 tmp <<= 1;
2671 /*
2672 * only one thread can access block_rsv at this point,
2673 * so we don't need hold lock to protect block_rsv.
2674 * we expand more reservation size here to allow enough
2675 * space for relocation and we will return eailer in
2676 * enospc case.
2677 */
2678 rc->block_rsv->size = tmp + fs_info->nodesize *
2679 RELOCATION_RESERVED_NODES;
2680 return -EAGAIN;
2681 }
2682
2683 return 0;
2684 }
2685
2686 /*
2687 * relocate a block tree, and then update pointers in upper level
2688 * blocks that reference the block to point to the new location.
2689 *
2690 * if called by link_to_upper, the block has already been relocated.
2691 * in that case this function just updates pointers.
2692 */
2693 static int do_relocation(struct btrfs_trans_handle *trans,
2694 struct reloc_control *rc,
2695 struct backref_node *node,
2696 struct btrfs_key *key,
2697 struct btrfs_path *path, int lowest)
2698 {
2699 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2700 struct backref_node *upper;
2701 struct backref_edge *edge;
2702 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2703 struct btrfs_root *root;
2704 struct extent_buffer *eb;
2705 u32 blocksize;
2706 u64 bytenr;
2707 u64 generation;
2708 int slot;
2709 int ret;
2710 int err = 0;
2711
2712 BUG_ON(lowest && node->eb);
2713
2714 path->lowest_level = node->level + 1;
2715 rc->backref_cache.path[node->level] = node;
2716 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2717 cond_resched();
2718
2719 upper = edge->node[UPPER];
2720 root = select_reloc_root(trans, rc, upper, edges);
2721 BUG_ON(!root);
2722
2723 if (upper->eb && !upper->locked) {
2724 if (!lowest) {
2725 ret = btrfs_bin_search(upper->eb, key,
2726 upper->level, &slot);
2727 BUG_ON(ret);
2728 bytenr = btrfs_node_blockptr(upper->eb, slot);
2729 if (node->eb->start == bytenr)
2730 goto next;
2731 }
2732 drop_node_buffer(upper);
2733 }
2734
2735 if (!upper->eb) {
2736 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2737 if (ret) {
2738 if (ret < 0)
2739 err = ret;
2740 else
2741 err = -ENOENT;
2742
2743 btrfs_release_path(path);
2744 break;
2745 }
2746
2747 if (!upper->eb) {
2748 upper->eb = path->nodes[upper->level];
2749 path->nodes[upper->level] = NULL;
2750 } else {
2751 BUG_ON(upper->eb != path->nodes[upper->level]);
2752 }
2753
2754 upper->locked = 1;
2755 path->locks[upper->level] = 0;
2756
2757 slot = path->slots[upper->level];
2758 btrfs_release_path(path);
2759 } else {
2760 ret = btrfs_bin_search(upper->eb, key, upper->level,
2761 &slot);
2762 BUG_ON(ret);
2763 }
2764
2765 bytenr = btrfs_node_blockptr(upper->eb, slot);
2766 if (lowest) {
2767 if (bytenr != node->bytenr) {
2768 btrfs_err(root->fs_info,
2769 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2770 bytenr, node->bytenr, slot,
2771 upper->eb->start);
2772 err = -EIO;
2773 goto next;
2774 }
2775 } else {
2776 if (node->eb->start == bytenr)
2777 goto next;
2778 }
2779
2780 blocksize = root->fs_info->nodesize;
2781 generation = btrfs_node_ptr_generation(upper->eb, slot);
2782 eb = read_tree_block(fs_info, bytenr, generation);
2783 if (IS_ERR(eb)) {
2784 err = PTR_ERR(eb);
2785 goto next;
2786 } else if (!extent_buffer_uptodate(eb)) {
2787 free_extent_buffer(eb);
2788 err = -EIO;
2789 goto next;
2790 }
2791 btrfs_tree_lock(eb);
2792 btrfs_set_lock_blocking(eb);
2793
2794 if (!node->eb) {
2795 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2796 slot, &eb);
2797 btrfs_tree_unlock(eb);
2798 free_extent_buffer(eb);
2799 if (ret < 0) {
2800 err = ret;
2801 goto next;
2802 }
2803 BUG_ON(node->eb != eb);
2804 } else {
2805 btrfs_set_node_blockptr(upper->eb, slot,
2806 node->eb->start);
2807 btrfs_set_node_ptr_generation(upper->eb, slot,
2808 trans->transid);
2809 btrfs_mark_buffer_dirty(upper->eb);
2810
2811 ret = btrfs_inc_extent_ref(trans, root->fs_info,
2812 node->eb->start, blocksize,
2813 upper->eb->start,
2814 btrfs_header_owner(upper->eb),
2815 node->level, 0);
2816 BUG_ON(ret);
2817
2818 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2819 BUG_ON(ret);
2820 }
2821 next:
2822 if (!upper->pending)
2823 drop_node_buffer(upper);
2824 else
2825 unlock_node_buffer(upper);
2826 if (err)
2827 break;
2828 }
2829
2830 if (!err && node->pending) {
2831 drop_node_buffer(node);
2832 list_move_tail(&node->list, &rc->backref_cache.changed);
2833 node->pending = 0;
2834 }
2835
2836 path->lowest_level = 0;
2837 BUG_ON(err == -ENOSPC);
2838 return err;
2839 }
2840
2841 static int link_to_upper(struct btrfs_trans_handle *trans,
2842 struct reloc_control *rc,
2843 struct backref_node *node,
2844 struct btrfs_path *path)
2845 {
2846 struct btrfs_key key;
2847
2848 btrfs_node_key_to_cpu(node->eb, &key, 0);
2849 return do_relocation(trans, rc, node, &key, path, 0);
2850 }
2851
2852 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2853 struct reloc_control *rc,
2854 struct btrfs_path *path, int err)
2855 {
2856 LIST_HEAD(list);
2857 struct backref_cache *cache = &rc->backref_cache;
2858 struct backref_node *node;
2859 int level;
2860 int ret;
2861
2862 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2863 while (!list_empty(&cache->pending[level])) {
2864 node = list_entry(cache->pending[level].next,
2865 struct backref_node, list);
2866 list_move_tail(&node->list, &list);
2867 BUG_ON(!node->pending);
2868
2869 if (!err) {
2870 ret = link_to_upper(trans, rc, node, path);
2871 if (ret < 0)
2872 err = ret;
2873 }
2874 }
2875 list_splice_init(&list, &cache->pending[level]);
2876 }
2877 return err;
2878 }
2879
2880 static void mark_block_processed(struct reloc_control *rc,
2881 u64 bytenr, u32 blocksize)
2882 {
2883 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2884 EXTENT_DIRTY);
2885 }
2886
2887 static void __mark_block_processed(struct reloc_control *rc,
2888 struct backref_node *node)
2889 {
2890 u32 blocksize;
2891 if (node->level == 0 ||
2892 in_block_group(node->bytenr, rc->block_group)) {
2893 blocksize = rc->extent_root->fs_info->nodesize;
2894 mark_block_processed(rc, node->bytenr, blocksize);
2895 }
2896 node->processed = 1;
2897 }
2898
2899 /*
2900 * mark a block and all blocks directly/indirectly reference the block
2901 * as processed.
2902 */
2903 static void update_processed_blocks(struct reloc_control *rc,
2904 struct backref_node *node)
2905 {
2906 struct backref_node *next = node;
2907 struct backref_edge *edge;
2908 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2909 int index = 0;
2910
2911 while (next) {
2912 cond_resched();
2913 while (1) {
2914 if (next->processed)
2915 break;
2916
2917 __mark_block_processed(rc, next);
2918
2919 if (list_empty(&next->upper))
2920 break;
2921
2922 edge = list_entry(next->upper.next,
2923 struct backref_edge, list[LOWER]);
2924 edges[index++] = edge;
2925 next = edge->node[UPPER];
2926 }
2927 next = walk_down_backref(edges, &index);
2928 }
2929 }
2930
2931 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2932 {
2933 u32 blocksize = rc->extent_root->fs_info->nodesize;
2934
2935 if (test_range_bit(&rc->processed_blocks, bytenr,
2936 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2937 return 1;
2938 return 0;
2939 }
2940
2941 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2942 struct tree_block *block)
2943 {
2944 struct extent_buffer *eb;
2945
2946 BUG_ON(block->key_ready);
2947 eb = read_tree_block(fs_info, block->bytenr, block->key.offset);
2948 if (IS_ERR(eb)) {
2949 return PTR_ERR(eb);
2950 } else if (!extent_buffer_uptodate(eb)) {
2951 free_extent_buffer(eb);
2952 return -EIO;
2953 }
2954 WARN_ON(btrfs_header_level(eb) != block->level);
2955 if (block->level == 0)
2956 btrfs_item_key_to_cpu(eb, &block->key, 0);
2957 else
2958 btrfs_node_key_to_cpu(eb, &block->key, 0);
2959 free_extent_buffer(eb);
2960 block->key_ready = 1;
2961 return 0;
2962 }
2963
2964 /*
2965 * helper function to relocate a tree block
2966 */
2967 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2968 struct reloc_control *rc,
2969 struct backref_node *node,
2970 struct btrfs_key *key,
2971 struct btrfs_path *path)
2972 {
2973 struct btrfs_root *root;
2974 int ret = 0;
2975
2976 if (!node)
2977 return 0;
2978
2979 BUG_ON(node->processed);
2980 root = select_one_root(node);
2981 if (root == ERR_PTR(-ENOENT)) {
2982 update_processed_blocks(rc, node);
2983 goto out;
2984 }
2985
2986 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2987 ret = reserve_metadata_space(trans, rc, node);
2988 if (ret)
2989 goto out;
2990 }
2991
2992 if (root) {
2993 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2994 BUG_ON(node->new_bytenr);
2995 BUG_ON(!list_empty(&node->list));
2996 btrfs_record_root_in_trans(trans, root);
2997 root = root->reloc_root;
2998 node->new_bytenr = root->node->start;
2999 node->root = root;
3000 list_add_tail(&node->list, &rc->backref_cache.changed);
3001 } else {
3002 path->lowest_level = node->level;
3003 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3004 btrfs_release_path(path);
3005 if (ret > 0)
3006 ret = 0;
3007 }
3008 if (!ret)
3009 update_processed_blocks(rc, node);
3010 } else {
3011 ret = do_relocation(trans, rc, node, key, path, 1);
3012 }
3013 out:
3014 if (ret || node->level == 0 || node->cowonly)
3015 remove_backref_node(&rc->backref_cache, node);
3016 return ret;
3017 }
3018
3019 /*
3020 * relocate a list of blocks
3021 */
3022 static noinline_for_stack
3023 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3024 struct reloc_control *rc, struct rb_root *blocks)
3025 {
3026 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3027 struct backref_node *node;
3028 struct btrfs_path *path;
3029 struct tree_block *block;
3030 struct rb_node *rb_node;
3031 int ret;
3032 int err = 0;
3033
3034 path = btrfs_alloc_path();
3035 if (!path) {
3036 err = -ENOMEM;
3037 goto out_free_blocks;
3038 }
3039
3040 rb_node = rb_first(blocks);
3041 while (rb_node) {
3042 block = rb_entry(rb_node, struct tree_block, rb_node);
3043 if (!block->key_ready)
3044 readahead_tree_block(fs_info, block->bytenr);
3045 rb_node = rb_next(rb_node);
3046 }
3047
3048 rb_node = rb_first(blocks);
3049 while (rb_node) {
3050 block = rb_entry(rb_node, struct tree_block, rb_node);
3051 if (!block->key_ready) {
3052 err = get_tree_block_key(fs_info, block);
3053 if (err)
3054 goto out_free_path;
3055 }
3056 rb_node = rb_next(rb_node);
3057 }
3058
3059 rb_node = rb_first(blocks);
3060 while (rb_node) {
3061 block = rb_entry(rb_node, struct tree_block, rb_node);
3062
3063 node = build_backref_tree(rc, &block->key,
3064 block->level, block->bytenr);
3065 if (IS_ERR(node)) {
3066 err = PTR_ERR(node);
3067 goto out;
3068 }
3069
3070 ret = relocate_tree_block(trans, rc, node, &block->key,
3071 path);
3072 if (ret < 0) {
3073 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3074 err = ret;
3075 goto out;
3076 }
3077 rb_node = rb_next(rb_node);
3078 }
3079 out:
3080 err = finish_pending_nodes(trans, rc, path, err);
3081
3082 out_free_path:
3083 btrfs_free_path(path);
3084 out_free_blocks:
3085 free_block_list(blocks);
3086 return err;
3087 }
3088
3089 static noinline_for_stack
3090 int prealloc_file_extent_cluster(struct inode *inode,
3091 struct file_extent_cluster *cluster)
3092 {
3093 u64 alloc_hint = 0;
3094 u64 start;
3095 u64 end;
3096 u64 offset = BTRFS_I(inode)->index_cnt;
3097 u64 num_bytes;
3098 int nr = 0;
3099 int ret = 0;
3100 u64 prealloc_start = cluster->start - offset;
3101 u64 prealloc_end = cluster->end - offset;
3102 u64 cur_offset;
3103 struct extent_changeset *data_reserved = NULL;
3104
3105 BUG_ON(cluster->start != cluster->boundary[0]);
3106 inode_lock(inode);
3107
3108 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3109 prealloc_end + 1 - prealloc_start);
3110 if (ret)
3111 goto out;
3112
3113 cur_offset = prealloc_start;
3114 while (nr < cluster->nr) {
3115 start = cluster->boundary[nr] - offset;
3116 if (nr + 1 < cluster->nr)
3117 end = cluster->boundary[nr + 1] - 1 - offset;
3118 else
3119 end = cluster->end - offset;
3120
3121 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3122 num_bytes = end + 1 - start;
3123 if (cur_offset < start)
3124 btrfs_free_reserved_data_space(inode, data_reserved,
3125 cur_offset, start - cur_offset);
3126 ret = btrfs_prealloc_file_range(inode, 0, start,
3127 num_bytes, num_bytes,
3128 end + 1, &alloc_hint);
3129 cur_offset = end + 1;
3130 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3131 if (ret)
3132 break;
3133 nr++;
3134 }
3135 if (cur_offset < prealloc_end)
3136 btrfs_free_reserved_data_space(inode, data_reserved,
3137 cur_offset, prealloc_end + 1 - cur_offset);
3138 out:
3139 inode_unlock(inode);
3140 extent_changeset_free(data_reserved);
3141 return ret;
3142 }
3143
3144 static noinline_for_stack
3145 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3146 u64 block_start)
3147 {
3148 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3149 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3150 struct extent_map *em;
3151 int ret = 0;
3152
3153 em = alloc_extent_map();
3154 if (!em)
3155 return -ENOMEM;
3156
3157 em->start = start;
3158 em->len = end + 1 - start;
3159 em->block_len = em->len;
3160 em->block_start = block_start;
3161 em->bdev = fs_info->fs_devices->latest_bdev;
3162 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3163
3164 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3165 while (1) {
3166 write_lock(&em_tree->lock);
3167 ret = add_extent_mapping(em_tree, em, 0);
3168 write_unlock(&em_tree->lock);
3169 if (ret != -EEXIST) {
3170 free_extent_map(em);
3171 break;
3172 }
3173 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3174 }
3175 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3176 return ret;
3177 }
3178
3179 static int relocate_file_extent_cluster(struct inode *inode,
3180 struct file_extent_cluster *cluster)
3181 {
3182 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3183 u64 page_start;
3184 u64 page_end;
3185 u64 offset = BTRFS_I(inode)->index_cnt;
3186 unsigned long index;
3187 unsigned long last_index;
3188 struct page *page;
3189 struct file_ra_state *ra;
3190 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3191 int nr = 0;
3192 int ret = 0;
3193
3194 if (!cluster->nr)
3195 return 0;
3196
3197 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3198 if (!ra)
3199 return -ENOMEM;
3200
3201 ret = prealloc_file_extent_cluster(inode, cluster);
3202 if (ret)
3203 goto out;
3204
3205 file_ra_state_init(ra, inode->i_mapping);
3206
3207 ret = setup_extent_mapping(inode, cluster->start - offset,
3208 cluster->end - offset, cluster->start);
3209 if (ret)
3210 goto out;
3211
3212 index = (cluster->start - offset) >> PAGE_SHIFT;
3213 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3214 while (index <= last_index) {
3215 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3216 PAGE_SIZE);
3217 if (ret)
3218 goto out;
3219
3220 page = find_lock_page(inode->i_mapping, index);
3221 if (!page) {
3222 page_cache_sync_readahead(inode->i_mapping,
3223 ra, NULL, index,
3224 last_index + 1 - index);
3225 page = find_or_create_page(inode->i_mapping, index,
3226 mask);
3227 if (!page) {
3228 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3229 PAGE_SIZE);
3230 ret = -ENOMEM;
3231 goto out;
3232 }
3233 }
3234
3235 if (PageReadahead(page)) {
3236 page_cache_async_readahead(inode->i_mapping,
3237 ra, NULL, page, index,
3238 last_index + 1 - index);
3239 }
3240
3241 if (!PageUptodate(page)) {
3242 btrfs_readpage(NULL, page);
3243 lock_page(page);
3244 if (!PageUptodate(page)) {
3245 unlock_page(page);
3246 put_page(page);
3247 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3248 PAGE_SIZE);
3249 ret = -EIO;
3250 goto out;
3251 }
3252 }
3253
3254 page_start = page_offset(page);
3255 page_end = page_start + PAGE_SIZE - 1;
3256
3257 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3258
3259 set_page_extent_mapped(page);
3260
3261 if (nr < cluster->nr &&
3262 page_start + offset == cluster->boundary[nr]) {
3263 set_extent_bits(&BTRFS_I(inode)->io_tree,
3264 page_start, page_end,
3265 EXTENT_BOUNDARY);
3266 nr++;
3267 }
3268
3269 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL, 0);
3270 set_page_dirty(page);
3271
3272 unlock_extent(&BTRFS_I(inode)->io_tree,
3273 page_start, page_end);
3274 unlock_page(page);
3275 put_page(page);
3276
3277 index++;
3278 balance_dirty_pages_ratelimited(inode->i_mapping);
3279 btrfs_throttle(fs_info);
3280 }
3281 WARN_ON(nr != cluster->nr);
3282 out:
3283 kfree(ra);
3284 return ret;
3285 }
3286
3287 static noinline_for_stack
3288 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3289 struct file_extent_cluster *cluster)
3290 {
3291 int ret;
3292
3293 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3294 ret = relocate_file_extent_cluster(inode, cluster);
3295 if (ret)
3296 return ret;
3297 cluster->nr = 0;
3298 }
3299
3300 if (!cluster->nr)
3301 cluster->start = extent_key->objectid;
3302 else
3303 BUG_ON(cluster->nr >= MAX_EXTENTS);
3304 cluster->end = extent_key->objectid + extent_key->offset - 1;
3305 cluster->boundary[cluster->nr] = extent_key->objectid;
3306 cluster->nr++;
3307
3308 if (cluster->nr >= MAX_EXTENTS) {
3309 ret = relocate_file_extent_cluster(inode, cluster);
3310 if (ret)
3311 return ret;
3312 cluster->nr = 0;
3313 }
3314 return 0;
3315 }
3316
3317 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3318 static int get_ref_objectid_v0(struct reloc_control *rc,
3319 struct btrfs_path *path,
3320 struct btrfs_key *extent_key,
3321 u64 *ref_objectid, int *path_change)
3322 {
3323 struct btrfs_key key;
3324 struct extent_buffer *leaf;
3325 struct btrfs_extent_ref_v0 *ref0;
3326 int ret;
3327 int slot;
3328
3329 leaf = path->nodes[0];
3330 slot = path->slots[0];
3331 while (1) {
3332 if (slot >= btrfs_header_nritems(leaf)) {
3333 ret = btrfs_next_leaf(rc->extent_root, path);
3334 if (ret < 0)
3335 return ret;
3336 BUG_ON(ret > 0);
3337 leaf = path->nodes[0];
3338 slot = path->slots[0];
3339 if (path_change)
3340 *path_change = 1;
3341 }
3342 btrfs_item_key_to_cpu(leaf, &key, slot);
3343 if (key.objectid != extent_key->objectid)
3344 return -ENOENT;
3345
3346 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3347 slot++;
3348 continue;
3349 }
3350 ref0 = btrfs_item_ptr(leaf, slot,
3351 struct btrfs_extent_ref_v0);
3352 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3353 break;
3354 }
3355 return 0;
3356 }
3357 #endif
3358
3359 /*
3360 * helper to add a tree block to the list.
3361 * the major work is getting the generation and level of the block
3362 */
3363 static int add_tree_block(struct reloc_control *rc,
3364 struct btrfs_key *extent_key,
3365 struct btrfs_path *path,
3366 struct rb_root *blocks)
3367 {
3368 struct extent_buffer *eb;
3369 struct btrfs_extent_item *ei;
3370 struct btrfs_tree_block_info *bi;
3371 struct tree_block *block;
3372 struct rb_node *rb_node;
3373 u32 item_size;
3374 int level = -1;
3375 u64 generation;
3376
3377 eb = path->nodes[0];
3378 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3379
3380 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3381 item_size >= sizeof(*ei) + sizeof(*bi)) {
3382 ei = btrfs_item_ptr(eb, path->slots[0],
3383 struct btrfs_extent_item);
3384 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3385 bi = (struct btrfs_tree_block_info *)(ei + 1);
3386 level = btrfs_tree_block_level(eb, bi);
3387 } else {
3388 level = (int)extent_key->offset;
3389 }
3390 generation = btrfs_extent_generation(eb, ei);
3391 } else {
3392 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3393 u64 ref_owner;
3394 int ret;
3395
3396 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3397 ret = get_ref_objectid_v0(rc, path, extent_key,
3398 &ref_owner, NULL);
3399 if (ret < 0)
3400 return ret;
3401 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3402 level = (int)ref_owner;
3403 /* FIXME: get real generation */
3404 generation = 0;
3405 #else
3406 BUG();
3407 #endif
3408 }
3409
3410 btrfs_release_path(path);
3411
3412 BUG_ON(level == -1);
3413
3414 block = kmalloc(sizeof(*block), GFP_NOFS);
3415 if (!block)
3416 return -ENOMEM;
3417
3418 block->bytenr = extent_key->objectid;
3419 block->key.objectid = rc->extent_root->fs_info->nodesize;
3420 block->key.offset = generation;
3421 block->level = level;
3422 block->key_ready = 0;
3423
3424 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3425 if (rb_node)
3426 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3427
3428 return 0;
3429 }
3430
3431 /*
3432 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3433 */
3434 static int __add_tree_block(struct reloc_control *rc,
3435 u64 bytenr, u32 blocksize,
3436 struct rb_root *blocks)
3437 {
3438 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3439 struct btrfs_path *path;
3440 struct btrfs_key key;
3441 int ret;
3442 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3443
3444 if (tree_block_processed(bytenr, rc))
3445 return 0;
3446
3447 if (tree_search(blocks, bytenr))
3448 return 0;
3449
3450 path = btrfs_alloc_path();
3451 if (!path)
3452 return -ENOMEM;
3453 again:
3454 key.objectid = bytenr;
3455 if (skinny) {
3456 key.type = BTRFS_METADATA_ITEM_KEY;
3457 key.offset = (u64)-1;
3458 } else {
3459 key.type = BTRFS_EXTENT_ITEM_KEY;
3460 key.offset = blocksize;
3461 }
3462
3463 path->search_commit_root = 1;
3464 path->skip_locking = 1;
3465 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3466 if (ret < 0)
3467 goto out;
3468
3469 if (ret > 0 && skinny) {
3470 if (path->slots[0]) {
3471 path->slots[0]--;
3472 btrfs_item_key_to_cpu(path->nodes[0], &key,
3473 path->slots[0]);
3474 if (key.objectid == bytenr &&
3475 (key.type == BTRFS_METADATA_ITEM_KEY ||
3476 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3477 key.offset == blocksize)))
3478 ret = 0;
3479 }
3480
3481 if (ret) {
3482 skinny = false;
3483 btrfs_release_path(path);
3484 goto again;
3485 }
3486 }
3487 if (ret) {
3488 ASSERT(ret == 1);
3489 btrfs_print_leaf(path->nodes[0]);
3490 btrfs_err(fs_info,
3491 "tree block extent item (%llu) is not found in extent tree",
3492 bytenr);
3493 WARN_ON(1);
3494 ret = -EINVAL;
3495 goto out;
3496 }
3497
3498 ret = add_tree_block(rc, &key, path, blocks);
3499 out:
3500 btrfs_free_path(path);
3501 return ret;
3502 }
3503
3504 /*
3505 * helper to check if the block use full backrefs for pointers in it
3506 */
3507 static int block_use_full_backref(struct reloc_control *rc,
3508 struct extent_buffer *eb)
3509 {
3510 u64 flags;
3511 int ret;
3512
3513 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3514 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3515 return 1;
3516
3517 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3518 eb->start, btrfs_header_level(eb), 1,
3519 NULL, &flags);
3520 BUG_ON(ret);
3521
3522 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3523 ret = 1;
3524 else
3525 ret = 0;
3526 return ret;
3527 }
3528
3529 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3530 struct btrfs_block_group_cache *block_group,
3531 struct inode *inode,
3532 u64 ino)
3533 {
3534 struct btrfs_key key;
3535 struct btrfs_root *root = fs_info->tree_root;
3536 struct btrfs_trans_handle *trans;
3537 int ret = 0;
3538
3539 if (inode)
3540 goto truncate;
3541
3542 key.objectid = ino;
3543 key.type = BTRFS_INODE_ITEM_KEY;
3544 key.offset = 0;
3545
3546 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3547 if (IS_ERR(inode) || is_bad_inode(inode)) {
3548 if (!IS_ERR(inode))
3549 iput(inode);
3550 return -ENOENT;
3551 }
3552
3553 truncate:
3554 ret = btrfs_check_trunc_cache_free_space(fs_info,
3555 &fs_info->global_block_rsv);
3556 if (ret)
3557 goto out;
3558
3559 trans = btrfs_join_transaction(root);
3560 if (IS_ERR(trans)) {
3561 ret = PTR_ERR(trans);
3562 goto out;
3563 }
3564
3565 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3566
3567 btrfs_end_transaction(trans);
3568 btrfs_btree_balance_dirty(fs_info);
3569 out:
3570 iput(inode);
3571 return ret;
3572 }
3573
3574 /*
3575 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3576 * this function scans fs tree to find blocks reference the data extent
3577 */
3578 static int find_data_references(struct reloc_control *rc,
3579 struct btrfs_key *extent_key,
3580 struct extent_buffer *leaf,
3581 struct btrfs_extent_data_ref *ref,
3582 struct rb_root *blocks)
3583 {
3584 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3585 struct btrfs_path *path;
3586 struct tree_block *block;
3587 struct btrfs_root *root;
3588 struct btrfs_file_extent_item *fi;
3589 struct rb_node *rb_node;
3590 struct btrfs_key key;
3591 u64 ref_root;
3592 u64 ref_objectid;
3593 u64 ref_offset;
3594 u32 ref_count;
3595 u32 nritems;
3596 int err = 0;
3597 int added = 0;
3598 int counted;
3599 int ret;
3600
3601 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3602 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3603 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3604 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3605
3606 /*
3607 * This is an extent belonging to the free space cache, lets just delete
3608 * it and redo the search.
3609 */
3610 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3611 ret = delete_block_group_cache(fs_info, rc->block_group,
3612 NULL, ref_objectid);
3613 if (ret != -ENOENT)
3614 return ret;
3615 ret = 0;
3616 }
3617
3618 path = btrfs_alloc_path();
3619 if (!path)
3620 return -ENOMEM;
3621 path->reada = READA_FORWARD;
3622
3623 root = read_fs_root(fs_info, ref_root);
3624 if (IS_ERR(root)) {
3625 err = PTR_ERR(root);
3626 goto out;
3627 }
3628
3629 key.objectid = ref_objectid;
3630 key.type = BTRFS_EXTENT_DATA_KEY;
3631 if (ref_offset > ((u64)-1 << 32))
3632 key.offset = 0;
3633 else
3634 key.offset = ref_offset;
3635
3636 path->search_commit_root = 1;
3637 path->skip_locking = 1;
3638 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3639 if (ret < 0) {
3640 err = ret;
3641 goto out;
3642 }
3643
3644 leaf = path->nodes[0];
3645 nritems = btrfs_header_nritems(leaf);
3646 /*
3647 * the references in tree blocks that use full backrefs
3648 * are not counted in
3649 */
3650 if (block_use_full_backref(rc, leaf))
3651 counted = 0;
3652 else
3653 counted = 1;
3654 rb_node = tree_search(blocks, leaf->start);
3655 if (rb_node) {
3656 if (counted)
3657 added = 1;
3658 else
3659 path->slots[0] = nritems;
3660 }
3661
3662 while (ref_count > 0) {
3663 while (path->slots[0] >= nritems) {
3664 ret = btrfs_next_leaf(root, path);
3665 if (ret < 0) {
3666 err = ret;
3667 goto out;
3668 }
3669 if (WARN_ON(ret > 0))
3670 goto out;
3671
3672 leaf = path->nodes[0];
3673 nritems = btrfs_header_nritems(leaf);
3674 added = 0;
3675
3676 if (block_use_full_backref(rc, leaf))
3677 counted = 0;
3678 else
3679 counted = 1;
3680 rb_node = tree_search(blocks, leaf->start);
3681 if (rb_node) {
3682 if (counted)
3683 added = 1;
3684 else
3685 path->slots[0] = nritems;
3686 }
3687 }
3688
3689 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3690 if (WARN_ON(key.objectid != ref_objectid ||
3691 key.type != BTRFS_EXTENT_DATA_KEY))
3692 break;
3693
3694 fi = btrfs_item_ptr(leaf, path->slots[0],
3695 struct btrfs_file_extent_item);
3696
3697 if (btrfs_file_extent_type(leaf, fi) ==
3698 BTRFS_FILE_EXTENT_INLINE)
3699 goto next;
3700
3701 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3702 extent_key->objectid)
3703 goto next;
3704
3705 key.offset -= btrfs_file_extent_offset(leaf, fi);
3706 if (key.offset != ref_offset)
3707 goto next;
3708
3709 if (counted)
3710 ref_count--;
3711 if (added)
3712 goto next;
3713
3714 if (!tree_block_processed(leaf->start, rc)) {
3715 block = kmalloc(sizeof(*block), GFP_NOFS);
3716 if (!block) {
3717 err = -ENOMEM;
3718 break;
3719 }
3720 block->bytenr = leaf->start;
3721 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3722 block->level = 0;
3723 block->key_ready = 1;
3724 rb_node = tree_insert(blocks, block->bytenr,
3725 &block->rb_node);
3726 if (rb_node)
3727 backref_tree_panic(rb_node, -EEXIST,
3728 block->bytenr);
3729 }
3730 if (counted)
3731 added = 1;
3732 else
3733 path->slots[0] = nritems;
3734 next:
3735 path->slots[0]++;
3736
3737 }
3738 out:
3739 btrfs_free_path(path);
3740 return err;
3741 }
3742
3743 /*
3744 * helper to find all tree blocks that reference a given data extent
3745 */
3746 static noinline_for_stack
3747 int add_data_references(struct reloc_control *rc,
3748 struct btrfs_key *extent_key,
3749 struct btrfs_path *path,
3750 struct rb_root *blocks)
3751 {
3752 struct btrfs_key key;
3753 struct extent_buffer *eb;
3754 struct btrfs_extent_data_ref *dref;
3755 struct btrfs_extent_inline_ref *iref;
3756 unsigned long ptr;
3757 unsigned long end;
3758 u32 blocksize = rc->extent_root->fs_info->nodesize;
3759 int ret = 0;
3760 int err = 0;
3761
3762 eb = path->nodes[0];
3763 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3764 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3765 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3766 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3767 ptr = end;
3768 else
3769 #endif
3770 ptr += sizeof(struct btrfs_extent_item);
3771
3772 while (ptr < end) {
3773 iref = (struct btrfs_extent_inline_ref *)ptr;
3774 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3775 BTRFS_REF_TYPE_DATA);
3776 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3777 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3778 ret = __add_tree_block(rc, key.offset, blocksize,
3779 blocks);
3780 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3781 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3782 ret = find_data_references(rc, extent_key,
3783 eb, dref, blocks);
3784 } else {
3785 ret = -EINVAL;
3786 btrfs_err(rc->extent_root->fs_info,
3787 "extent %llu slot %d has an invalid inline ref type",
3788 eb->start, path->slots[0]);
3789 }
3790 if (ret) {
3791 err = ret;
3792 goto out;
3793 }
3794 ptr += btrfs_extent_inline_ref_size(key.type);
3795 }
3796 WARN_ON(ptr > end);
3797
3798 while (1) {
3799 cond_resched();
3800 eb = path->nodes[0];
3801 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3802 ret = btrfs_next_leaf(rc->extent_root, path);
3803 if (ret < 0) {
3804 err = ret;
3805 break;
3806 }
3807 if (ret > 0)
3808 break;
3809 eb = path->nodes[0];
3810 }
3811
3812 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3813 if (key.objectid != extent_key->objectid)
3814 break;
3815
3816 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3817 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3818 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3819 #else
3820 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3821 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3822 #endif
3823 ret = __add_tree_block(rc, key.offset, blocksize,
3824 blocks);
3825 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3826 dref = btrfs_item_ptr(eb, path->slots[0],
3827 struct btrfs_extent_data_ref);
3828 ret = find_data_references(rc, extent_key,
3829 eb, dref, blocks);
3830 } else {
3831 ret = 0;
3832 }
3833 if (ret) {
3834 err = ret;
3835 break;
3836 }
3837 path->slots[0]++;
3838 }
3839 out:
3840 btrfs_release_path(path);
3841 if (err)
3842 free_block_list(blocks);
3843 return err;
3844 }
3845
3846 /*
3847 * helper to find next unprocessed extent
3848 */
3849 static noinline_for_stack
3850 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3851 struct btrfs_key *extent_key)
3852 {
3853 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3854 struct btrfs_key key;
3855 struct extent_buffer *leaf;
3856 u64 start, end, last;
3857 int ret;
3858
3859 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3860 while (1) {
3861 cond_resched();
3862 if (rc->search_start >= last) {
3863 ret = 1;
3864 break;
3865 }
3866
3867 key.objectid = rc->search_start;
3868 key.type = BTRFS_EXTENT_ITEM_KEY;
3869 key.offset = 0;
3870
3871 path->search_commit_root = 1;
3872 path->skip_locking = 1;
3873 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3874 0, 0);
3875 if (ret < 0)
3876 break;
3877 next:
3878 leaf = path->nodes[0];
3879 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3880 ret = btrfs_next_leaf(rc->extent_root, path);
3881 if (ret != 0)
3882 break;
3883 leaf = path->nodes[0];
3884 }
3885
3886 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3887 if (key.objectid >= last) {
3888 ret = 1;
3889 break;
3890 }
3891
3892 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3893 key.type != BTRFS_METADATA_ITEM_KEY) {
3894 path->slots[0]++;
3895 goto next;
3896 }
3897
3898 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3899 key.objectid + key.offset <= rc->search_start) {
3900 path->slots[0]++;
3901 goto next;
3902 }
3903
3904 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3905 key.objectid + fs_info->nodesize <=
3906 rc->search_start) {
3907 path->slots[0]++;
3908 goto next;
3909 }
3910
3911 ret = find_first_extent_bit(&rc->processed_blocks,
3912 key.objectid, &start, &end,
3913 EXTENT_DIRTY, NULL);
3914
3915 if (ret == 0 && start <= key.objectid) {
3916 btrfs_release_path(path);
3917 rc->search_start = end + 1;
3918 } else {
3919 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3920 rc->search_start = key.objectid + key.offset;
3921 else
3922 rc->search_start = key.objectid +
3923 fs_info->nodesize;
3924 memcpy(extent_key, &key, sizeof(key));
3925 return 0;
3926 }
3927 }
3928 btrfs_release_path(path);
3929 return ret;
3930 }
3931
3932 static void set_reloc_control(struct reloc_control *rc)
3933 {
3934 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3935
3936 mutex_lock(&fs_info->reloc_mutex);
3937 fs_info->reloc_ctl = rc;
3938 mutex_unlock(&fs_info->reloc_mutex);
3939 }
3940
3941 static void unset_reloc_control(struct reloc_control *rc)
3942 {
3943 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3944
3945 mutex_lock(&fs_info->reloc_mutex);
3946 fs_info->reloc_ctl = NULL;
3947 mutex_unlock(&fs_info->reloc_mutex);
3948 }
3949
3950 static int check_extent_flags(u64 flags)
3951 {
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_EXTENT_FLAG_TREE_BLOCK))
3957 return 1;
3958 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3959 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3960 return 1;
3961 return 0;
3962 }
3963
3964 static noinline_for_stack
3965 int prepare_to_relocate(struct reloc_control *rc)
3966 {
3967 struct btrfs_trans_handle *trans;
3968 int ret;
3969
3970 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3971 BTRFS_BLOCK_RSV_TEMP);
3972 if (!rc->block_rsv)
3973 return -ENOMEM;
3974
3975 memset(&rc->cluster, 0, sizeof(rc->cluster));
3976 rc->search_start = rc->block_group->key.objectid;
3977 rc->extents_found = 0;
3978 rc->nodes_relocated = 0;
3979 rc->merging_rsv_size = 0;
3980 rc->reserved_bytes = 0;
3981 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3982 RELOCATION_RESERVED_NODES;
3983 ret = btrfs_block_rsv_refill(rc->extent_root,
3984 rc->block_rsv, rc->block_rsv->size,
3985 BTRFS_RESERVE_FLUSH_ALL);
3986 if (ret)
3987 return ret;
3988
3989 rc->create_reloc_tree = 1;
3990 set_reloc_control(rc);
3991
3992 trans = btrfs_join_transaction(rc->extent_root);
3993 if (IS_ERR(trans)) {
3994 unset_reloc_control(rc);
3995 /*
3996 * extent tree is not a ref_cow tree and has no reloc_root to
3997 * cleanup. And callers are responsible to free the above
3998 * block rsv.
3999 */
4000 return PTR_ERR(trans);
4001 }
4002 btrfs_commit_transaction(trans);
4003 return 0;
4004 }
4005
4006 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4007 {
4008 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
4009 struct rb_root blocks = RB_ROOT;
4010 struct btrfs_key key;
4011 struct btrfs_trans_handle *trans = NULL;
4012 struct btrfs_path *path;
4013 struct btrfs_extent_item *ei;
4014 u64 flags;
4015 u32 item_size;
4016 int ret;
4017 int err = 0;
4018 int progress = 0;
4019
4020 path = btrfs_alloc_path();
4021 if (!path)
4022 return -ENOMEM;
4023 path->reada = READA_FORWARD;
4024
4025 ret = prepare_to_relocate(rc);
4026 if (ret) {
4027 err = ret;
4028 goto out_free;
4029 }
4030
4031 while (1) {
4032 rc->reserved_bytes = 0;
4033 ret = btrfs_block_rsv_refill(rc->extent_root,
4034 rc->block_rsv, rc->block_rsv->size,
4035 BTRFS_RESERVE_FLUSH_ALL);
4036 if (ret) {
4037 err = ret;
4038 break;
4039 }
4040 progress++;
4041 trans = btrfs_start_transaction(rc->extent_root, 0);
4042 if (IS_ERR(trans)) {
4043 err = PTR_ERR(trans);
4044 trans = NULL;
4045 break;
4046 }
4047 restart:
4048 if (update_backref_cache(trans, &rc->backref_cache)) {
4049 btrfs_end_transaction(trans);
4050 continue;
4051 }
4052
4053 ret = find_next_extent(rc, path, &key);
4054 if (ret < 0)
4055 err = ret;
4056 if (ret != 0)
4057 break;
4058
4059 rc->extents_found++;
4060
4061 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4062 struct btrfs_extent_item);
4063 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4064 if (item_size >= sizeof(*ei)) {
4065 flags = btrfs_extent_flags(path->nodes[0], ei);
4066 ret = check_extent_flags(flags);
4067 BUG_ON(ret);
4068
4069 } else {
4070 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4071 u64 ref_owner;
4072 int path_change = 0;
4073
4074 BUG_ON(item_size !=
4075 sizeof(struct btrfs_extent_item_v0));
4076 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
4077 &path_change);
4078 if (ret < 0) {
4079 err = ret;
4080 break;
4081 }
4082 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
4083 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
4084 else
4085 flags = BTRFS_EXTENT_FLAG_DATA;
4086
4087 if (path_change) {
4088 btrfs_release_path(path);
4089
4090 path->search_commit_root = 1;
4091 path->skip_locking = 1;
4092 ret = btrfs_search_slot(NULL, rc->extent_root,
4093 &key, path, 0, 0);
4094 if (ret < 0) {
4095 err = ret;
4096 break;
4097 }
4098 BUG_ON(ret > 0);
4099 }
4100 #else
4101 BUG();
4102 #endif
4103 }
4104
4105 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4106 ret = add_tree_block(rc, &key, path, &blocks);
4107 } else if (rc->stage == UPDATE_DATA_PTRS &&
4108 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4109 ret = add_data_references(rc, &key, path, &blocks);
4110 } else {
4111 btrfs_release_path(path);
4112 ret = 0;
4113 }
4114 if (ret < 0) {
4115 err = ret;
4116 break;
4117 }
4118
4119 if (!RB_EMPTY_ROOT(&blocks)) {
4120 ret = relocate_tree_blocks(trans, rc, &blocks);
4121 if (ret < 0) {
4122 /*
4123 * if we fail to relocate tree blocks, force to update
4124 * backref cache when committing transaction.
4125 */
4126 rc->backref_cache.last_trans = trans->transid - 1;
4127
4128 if (ret != -EAGAIN) {
4129 err = ret;
4130 break;
4131 }
4132 rc->extents_found--;
4133 rc->search_start = key.objectid;
4134 }
4135 }
4136
4137 btrfs_end_transaction_throttle(trans);
4138 btrfs_btree_balance_dirty(fs_info);
4139 trans = NULL;
4140
4141 if (rc->stage == MOVE_DATA_EXTENTS &&
4142 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4143 rc->found_file_extent = 1;
4144 ret = relocate_data_extent(rc->data_inode,
4145 &key, &rc->cluster);
4146 if (ret < 0) {
4147 err = ret;
4148 break;
4149 }
4150 }
4151 }
4152 if (trans && progress && err == -ENOSPC) {
4153 ret = btrfs_force_chunk_alloc(trans, fs_info,
4154 rc->block_group->flags);
4155 if (ret == 1) {
4156 err = 0;
4157 progress = 0;
4158 goto restart;
4159 }
4160 }
4161
4162 btrfs_release_path(path);
4163 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4164
4165 if (trans) {
4166 btrfs_end_transaction_throttle(trans);
4167 btrfs_btree_balance_dirty(fs_info);
4168 }
4169
4170 if (!err) {
4171 ret = relocate_file_extent_cluster(rc->data_inode,
4172 &rc->cluster);
4173 if (ret < 0)
4174 err = ret;
4175 }
4176
4177 rc->create_reloc_tree = 0;
4178 set_reloc_control(rc);
4179
4180 backref_cache_cleanup(&rc->backref_cache);
4181 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4182
4183 err = prepare_to_merge(rc, err);
4184
4185 merge_reloc_roots(rc);
4186
4187 rc->merge_reloc_tree = 0;
4188 unset_reloc_control(rc);
4189 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4190
4191 /* get rid of pinned extents */
4192 trans = btrfs_join_transaction(rc->extent_root);
4193 if (IS_ERR(trans)) {
4194 err = PTR_ERR(trans);
4195 goto out_free;
4196 }
4197 btrfs_commit_transaction(trans);
4198 out_free:
4199 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4200 btrfs_free_path(path);
4201 return err;
4202 }
4203
4204 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4205 struct btrfs_root *root, u64 objectid)
4206 {
4207 struct btrfs_path *path;
4208 struct btrfs_inode_item *item;
4209 struct extent_buffer *leaf;
4210 int ret;
4211
4212 path = btrfs_alloc_path();
4213 if (!path)
4214 return -ENOMEM;
4215
4216 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4217 if (ret)
4218 goto out;
4219
4220 leaf = path->nodes[0];
4221 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4222 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4223 btrfs_set_inode_generation(leaf, item, 1);
4224 btrfs_set_inode_size(leaf, item, 0);
4225 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4226 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4227 BTRFS_INODE_PREALLOC);
4228 btrfs_mark_buffer_dirty(leaf);
4229 out:
4230 btrfs_free_path(path);
4231 return ret;
4232 }
4233
4234 /*
4235 * helper to create inode for data relocation.
4236 * the inode is in data relocation tree and its link count is 0
4237 */
4238 static noinline_for_stack
4239 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4240 struct btrfs_block_group_cache *group)
4241 {
4242 struct inode *inode = NULL;
4243 struct btrfs_trans_handle *trans;
4244 struct btrfs_root *root;
4245 struct btrfs_key key;
4246 u64 objectid;
4247 int err = 0;
4248
4249 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4250 if (IS_ERR(root))
4251 return ERR_CAST(root);
4252
4253 trans = btrfs_start_transaction(root, 6);
4254 if (IS_ERR(trans))
4255 return ERR_CAST(trans);
4256
4257 err = btrfs_find_free_objectid(root, &objectid);
4258 if (err)
4259 goto out;
4260
4261 err = __insert_orphan_inode(trans, root, objectid);
4262 BUG_ON(err);
4263
4264 key.objectid = objectid;
4265 key.type = BTRFS_INODE_ITEM_KEY;
4266 key.offset = 0;
4267 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4268 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4269 BTRFS_I(inode)->index_cnt = group->key.objectid;
4270
4271 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4272 out:
4273 btrfs_end_transaction(trans);
4274 btrfs_btree_balance_dirty(fs_info);
4275 if (err) {
4276 if (inode)
4277 iput(inode);
4278 inode = ERR_PTR(err);
4279 }
4280 return inode;
4281 }
4282
4283 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4284 {
4285 struct reloc_control *rc;
4286
4287 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4288 if (!rc)
4289 return NULL;
4290
4291 INIT_LIST_HEAD(&rc->reloc_roots);
4292 backref_cache_init(&rc->backref_cache);
4293 mapping_tree_init(&rc->reloc_root_tree);
4294 extent_io_tree_init(&rc->processed_blocks, NULL);
4295 return rc;
4296 }
4297
4298 /*
4299 * Print the block group being relocated
4300 */
4301 static void describe_relocation(struct btrfs_fs_info *fs_info,
4302 struct btrfs_block_group_cache *block_group)
4303 {
4304 char buf[128]; /* prefixed by a '|' that'll be dropped */
4305 u64 flags = block_group->flags;
4306
4307 /* Shouldn't happen */
4308 if (!flags) {
4309 strcpy(buf, "|NONE");
4310 } else {
4311 char *bp = buf;
4312
4313 #define DESCRIBE_FLAG(f, d) \
4314 if (flags & BTRFS_BLOCK_GROUP_##f) { \
4315 bp += snprintf(bp, buf - bp + sizeof(buf), "|%s", d); \
4316 flags &= ~BTRFS_BLOCK_GROUP_##f; \
4317 }
4318 DESCRIBE_FLAG(DATA, "data");
4319 DESCRIBE_FLAG(SYSTEM, "system");
4320 DESCRIBE_FLAG(METADATA, "metadata");
4321 DESCRIBE_FLAG(RAID0, "raid0");
4322 DESCRIBE_FLAG(RAID1, "raid1");
4323 DESCRIBE_FLAG(DUP, "dup");
4324 DESCRIBE_FLAG(RAID10, "raid10");
4325 DESCRIBE_FLAG(RAID5, "raid5");
4326 DESCRIBE_FLAG(RAID6, "raid6");
4327 if (flags)
4328 snprintf(buf, buf - bp + sizeof(buf), "|0x%llx", flags);
4329 #undef DESCRIBE_FLAG
4330 }
4331
4332 btrfs_info(fs_info,
4333 "relocating block group %llu flags %s",
4334 block_group->key.objectid, buf + 1);
4335 }
4336
4337 /*
4338 * function to relocate all extents in a block group.
4339 */
4340 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4341 {
4342 struct btrfs_root *extent_root = fs_info->extent_root;
4343 struct reloc_control *rc;
4344 struct inode *inode;
4345 struct btrfs_path *path;
4346 int ret;
4347 int rw = 0;
4348 int err = 0;
4349
4350 rc = alloc_reloc_control(fs_info);
4351 if (!rc)
4352 return -ENOMEM;
4353
4354 rc->extent_root = extent_root;
4355
4356 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4357 BUG_ON(!rc->block_group);
4358
4359 ret = btrfs_inc_block_group_ro(fs_info, rc->block_group);
4360 if (ret) {
4361 err = ret;
4362 goto out;
4363 }
4364 rw = 1;
4365
4366 path = btrfs_alloc_path();
4367 if (!path) {
4368 err = -ENOMEM;
4369 goto out;
4370 }
4371
4372 inode = lookup_free_space_inode(fs_info, rc->block_group, path);
4373 btrfs_free_path(path);
4374
4375 if (!IS_ERR(inode))
4376 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4377 else
4378 ret = PTR_ERR(inode);
4379
4380 if (ret && ret != -ENOENT) {
4381 err = ret;
4382 goto out;
4383 }
4384
4385 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4386 if (IS_ERR(rc->data_inode)) {
4387 err = PTR_ERR(rc->data_inode);
4388 rc->data_inode = NULL;
4389 goto out;
4390 }
4391
4392 describe_relocation(fs_info, rc->block_group);
4393
4394 btrfs_wait_block_group_reservations(rc->block_group);
4395 btrfs_wait_nocow_writers(rc->block_group);
4396 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4397 rc->block_group->key.objectid,
4398 rc->block_group->key.offset);
4399
4400 while (1) {
4401 mutex_lock(&fs_info->cleaner_mutex);
4402 ret = relocate_block_group(rc);
4403 mutex_unlock(&fs_info->cleaner_mutex);
4404 if (ret < 0) {
4405 err = ret;
4406 goto out;
4407 }
4408
4409 if (rc->extents_found == 0)
4410 break;
4411
4412 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4413
4414 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4415 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4416 (u64)-1);
4417 if (ret) {
4418 err = ret;
4419 goto out;
4420 }
4421 invalidate_mapping_pages(rc->data_inode->i_mapping,
4422 0, -1);
4423 rc->stage = UPDATE_DATA_PTRS;
4424 }
4425 }
4426
4427 WARN_ON(rc->block_group->pinned > 0);
4428 WARN_ON(rc->block_group->reserved > 0);
4429 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4430 out:
4431 if (err && rw)
4432 btrfs_dec_block_group_ro(rc->block_group);
4433 iput(rc->data_inode);
4434 btrfs_put_block_group(rc->block_group);
4435 kfree(rc);
4436 return err;
4437 }
4438
4439 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4440 {
4441 struct btrfs_fs_info *fs_info = root->fs_info;
4442 struct btrfs_trans_handle *trans;
4443 int ret, err;
4444
4445 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4446 if (IS_ERR(trans))
4447 return PTR_ERR(trans);
4448
4449 memset(&root->root_item.drop_progress, 0,
4450 sizeof(root->root_item.drop_progress));
4451 root->root_item.drop_level = 0;
4452 btrfs_set_root_refs(&root->root_item, 0);
4453 ret = btrfs_update_root(trans, fs_info->tree_root,
4454 &root->root_key, &root->root_item);
4455
4456 err = btrfs_end_transaction(trans);
4457 if (err)
4458 return err;
4459 return ret;
4460 }
4461
4462 /*
4463 * recover relocation interrupted by system crash.
4464 *
4465 * this function resumes merging reloc trees with corresponding fs trees.
4466 * this is important for keeping the sharing of tree blocks
4467 */
4468 int btrfs_recover_relocation(struct btrfs_root *root)
4469 {
4470 struct btrfs_fs_info *fs_info = root->fs_info;
4471 LIST_HEAD(reloc_roots);
4472 struct btrfs_key key;
4473 struct btrfs_root *fs_root;
4474 struct btrfs_root *reloc_root;
4475 struct btrfs_path *path;
4476 struct extent_buffer *leaf;
4477 struct reloc_control *rc = NULL;
4478 struct btrfs_trans_handle *trans;
4479 int ret;
4480 int err = 0;
4481
4482 path = btrfs_alloc_path();
4483 if (!path)
4484 return -ENOMEM;
4485 path->reada = READA_BACK;
4486
4487 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4488 key.type = BTRFS_ROOT_ITEM_KEY;
4489 key.offset = (u64)-1;
4490
4491 while (1) {
4492 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4493 path, 0, 0);
4494 if (ret < 0) {
4495 err = ret;
4496 goto out;
4497 }
4498 if (ret > 0) {
4499 if (path->slots[0] == 0)
4500 break;
4501 path->slots[0]--;
4502 }
4503 leaf = path->nodes[0];
4504 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4505 btrfs_release_path(path);
4506
4507 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4508 key.type != BTRFS_ROOT_ITEM_KEY)
4509 break;
4510
4511 reloc_root = btrfs_read_fs_root(root, &key);
4512 if (IS_ERR(reloc_root)) {
4513 err = PTR_ERR(reloc_root);
4514 goto out;
4515 }
4516
4517 list_add(&reloc_root->root_list, &reloc_roots);
4518
4519 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4520 fs_root = read_fs_root(fs_info,
4521 reloc_root->root_key.offset);
4522 if (IS_ERR(fs_root)) {
4523 ret = PTR_ERR(fs_root);
4524 if (ret != -ENOENT) {
4525 err = ret;
4526 goto out;
4527 }
4528 ret = mark_garbage_root(reloc_root);
4529 if (ret < 0) {
4530 err = ret;
4531 goto out;
4532 }
4533 }
4534 }
4535
4536 if (key.offset == 0)
4537 break;
4538
4539 key.offset--;
4540 }
4541 btrfs_release_path(path);
4542
4543 if (list_empty(&reloc_roots))
4544 goto out;
4545
4546 rc = alloc_reloc_control(fs_info);
4547 if (!rc) {
4548 err = -ENOMEM;
4549 goto out;
4550 }
4551
4552 rc->extent_root = fs_info->extent_root;
4553
4554 set_reloc_control(rc);
4555
4556 trans = btrfs_join_transaction(rc->extent_root);
4557 if (IS_ERR(trans)) {
4558 unset_reloc_control(rc);
4559 err = PTR_ERR(trans);
4560 goto out_free;
4561 }
4562
4563 rc->merge_reloc_tree = 1;
4564
4565 while (!list_empty(&reloc_roots)) {
4566 reloc_root = list_entry(reloc_roots.next,
4567 struct btrfs_root, root_list);
4568 list_del(&reloc_root->root_list);
4569
4570 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4571 list_add_tail(&reloc_root->root_list,
4572 &rc->reloc_roots);
4573 continue;
4574 }
4575
4576 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4577 if (IS_ERR(fs_root)) {
4578 err = PTR_ERR(fs_root);
4579 goto out_free;
4580 }
4581
4582 err = __add_reloc_root(reloc_root);
4583 BUG_ON(err < 0); /* -ENOMEM or logic error */
4584 fs_root->reloc_root = reloc_root;
4585 }
4586
4587 err = btrfs_commit_transaction(trans);
4588 if (err)
4589 goto out_free;
4590
4591 merge_reloc_roots(rc);
4592
4593 unset_reloc_control(rc);
4594
4595 trans = btrfs_join_transaction(rc->extent_root);
4596 if (IS_ERR(trans)) {
4597 err = PTR_ERR(trans);
4598 goto out_free;
4599 }
4600 err = btrfs_commit_transaction(trans);
4601 out_free:
4602 kfree(rc);
4603 out:
4604 if (!list_empty(&reloc_roots))
4605 free_reloc_roots(&reloc_roots);
4606
4607 btrfs_free_path(path);
4608
4609 if (err == 0) {
4610 /* cleanup orphan inode in data relocation tree */
4611 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4612 if (IS_ERR(fs_root))
4613 err = PTR_ERR(fs_root);
4614 else
4615 err = btrfs_orphan_cleanup(fs_root);
4616 }
4617 return err;
4618 }
4619
4620 /*
4621 * helper to add ordered checksum for data relocation.
4622 *
4623 * cloning checksum properly handles the nodatasum extents.
4624 * it also saves CPU time to re-calculate the checksum.
4625 */
4626 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4627 {
4628 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4629 struct btrfs_ordered_sum *sums;
4630 struct btrfs_ordered_extent *ordered;
4631 int ret;
4632 u64 disk_bytenr;
4633 u64 new_bytenr;
4634 LIST_HEAD(list);
4635
4636 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4637 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4638
4639 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4640 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4641 disk_bytenr + len - 1, &list, 0);
4642 if (ret)
4643 goto out;
4644
4645 while (!list_empty(&list)) {
4646 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4647 list_del_init(&sums->list);
4648
4649 /*
4650 * We need to offset the new_bytenr based on where the csum is.
4651 * We need to do this because we will read in entire prealloc
4652 * extents but we may have written to say the middle of the
4653 * prealloc extent, so we need to make sure the csum goes with
4654 * the right disk offset.
4655 *
4656 * We can do this because the data reloc inode refers strictly
4657 * to the on disk bytes, so we don't have to worry about
4658 * disk_len vs real len like with real inodes since it's all
4659 * disk length.
4660 */
4661 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4662 sums->bytenr = new_bytenr;
4663
4664 btrfs_add_ordered_sum(inode, ordered, sums);
4665 }
4666 out:
4667 btrfs_put_ordered_extent(ordered);
4668 return ret;
4669 }
4670
4671 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4672 struct btrfs_root *root, struct extent_buffer *buf,
4673 struct extent_buffer *cow)
4674 {
4675 struct btrfs_fs_info *fs_info = root->fs_info;
4676 struct reloc_control *rc;
4677 struct backref_node *node;
4678 int first_cow = 0;
4679 int level;
4680 int ret = 0;
4681
4682 rc = fs_info->reloc_ctl;
4683 if (!rc)
4684 return 0;
4685
4686 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4687 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4688
4689 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4690 if (buf == root->node)
4691 __update_reloc_root(root, cow->start);
4692 }
4693
4694 level = btrfs_header_level(buf);
4695 if (btrfs_header_generation(buf) <=
4696 btrfs_root_last_snapshot(&root->root_item))
4697 first_cow = 1;
4698
4699 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4700 rc->create_reloc_tree) {
4701 WARN_ON(!first_cow && level == 0);
4702
4703 node = rc->backref_cache.path[level];
4704 BUG_ON(node->bytenr != buf->start &&
4705 node->new_bytenr != buf->start);
4706
4707 drop_node_buffer(node);
4708 extent_buffer_get(cow);
4709 node->eb = cow;
4710 node->new_bytenr = cow->start;
4711
4712 if (!node->pending) {
4713 list_move_tail(&node->list,
4714 &rc->backref_cache.pending[level]);
4715 node->pending = 1;
4716 }
4717
4718 if (first_cow)
4719 __mark_block_processed(rc, node);
4720
4721 if (first_cow && level > 0)
4722 rc->nodes_relocated += buf->len;
4723 }
4724
4725 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4726 ret = replace_file_extents(trans, rc, root, cow);
4727 return ret;
4728 }
4729
4730 /*
4731 * called before creating snapshot. it calculates metadata reservation
4732 * required for relocating tree blocks in the snapshot
4733 */
4734 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4735 u64 *bytes_to_reserve)
4736 {
4737 struct btrfs_root *root;
4738 struct reloc_control *rc;
4739
4740 root = pending->root;
4741 if (!root->reloc_root)
4742 return;
4743
4744 rc = root->fs_info->reloc_ctl;
4745 if (!rc->merge_reloc_tree)
4746 return;
4747
4748 root = root->reloc_root;
4749 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4750 /*
4751 * relocation is in the stage of merging trees. the space
4752 * used by merging a reloc tree is twice the size of
4753 * relocated tree nodes in the worst case. half for cowing
4754 * the reloc tree, half for cowing the fs tree. the space
4755 * used by cowing the reloc tree will be freed after the
4756 * tree is dropped. if we create snapshot, cowing the fs
4757 * tree may use more space than it frees. so we need
4758 * reserve extra space.
4759 */
4760 *bytes_to_reserve += rc->nodes_relocated;
4761 }
4762
4763 /*
4764 * called after snapshot is created. migrate block reservation
4765 * and create reloc root for the newly created snapshot
4766 */
4767 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4768 struct btrfs_pending_snapshot *pending)
4769 {
4770 struct btrfs_root *root = pending->root;
4771 struct btrfs_root *reloc_root;
4772 struct btrfs_root *new_root;
4773 struct reloc_control *rc;
4774 int ret;
4775
4776 if (!root->reloc_root)
4777 return 0;
4778
4779 rc = root->fs_info->reloc_ctl;
4780 rc->merging_rsv_size += rc->nodes_relocated;
4781
4782 if (rc->merge_reloc_tree) {
4783 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4784 rc->block_rsv,
4785 rc->nodes_relocated, 1);
4786 if (ret)
4787 return ret;
4788 }
4789
4790 new_root = pending->snap;
4791 reloc_root = create_reloc_root(trans, root->reloc_root,
4792 new_root->root_key.objectid);
4793 if (IS_ERR(reloc_root))
4794 return PTR_ERR(reloc_root);
4795
4796 ret = __add_reloc_root(reloc_root);
4797 BUG_ON(ret < 0);
4798 new_root->reloc_root = reloc_root;
4799
4800 if (rc->create_reloc_tree)
4801 ret = clone_backref_node(trans, rc, root, reloc_root);
4802 return ret;
4803 }
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