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Merge branch 'for-linus-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/mason...
[deliverable/linux.git] / fs / btrfs / relocation.c
1 /*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33 #include "inode-map.h"
34
35 /*
36 * backref_node, mapping_node and tree_block start with this
37 */
38 struct tree_entry {
39 struct rb_node rb_node;
40 u64 bytenr;
41 };
42
43 /*
44 * present a tree block in the backref cache
45 */
46 struct backref_node {
47 struct rb_node rb_node;
48 u64 bytenr;
49
50 u64 new_bytenr;
51 /* objectid of tree block owner, can be not uptodate */
52 u64 owner;
53 /* link to pending, changed or detached list */
54 struct list_head list;
55 /* list of upper level blocks reference this block */
56 struct list_head upper;
57 /* list of child blocks in the cache */
58 struct list_head lower;
59 /* NULL if this node is not tree root */
60 struct btrfs_root *root;
61 /* extent buffer got by COW the block */
62 struct extent_buffer *eb;
63 /* level of tree block */
64 unsigned int level:8;
65 /* is the block in non-reference counted tree */
66 unsigned int cowonly:1;
67 /* 1 if no child node in the cache */
68 unsigned int lowest:1;
69 /* is the extent buffer locked */
70 unsigned int locked:1;
71 /* has the block been processed */
72 unsigned int processed:1;
73 /* have backrefs of this block been checked */
74 unsigned int checked:1;
75 /*
76 * 1 if corresponding block has been cowed but some upper
77 * level block pointers may not point to the new location
78 */
79 unsigned int pending:1;
80 /*
81 * 1 if the backref node isn't connected to any other
82 * backref node.
83 */
84 unsigned int detached:1;
85 };
86
87 /*
88 * present a block pointer in the backref cache
89 */
90 struct backref_edge {
91 struct list_head list[2];
92 struct backref_node *node[2];
93 };
94
95 #define LOWER 0
96 #define UPPER 1
97 #define RELOCATION_RESERVED_NODES 256
98
99 struct backref_cache {
100 /* red black tree of all backref nodes in the cache */
101 struct rb_root rb_root;
102 /* for passing backref nodes to btrfs_reloc_cow_block */
103 struct backref_node *path[BTRFS_MAX_LEVEL];
104 /*
105 * list of blocks that have been cowed but some block
106 * pointers in upper level blocks may not reflect the
107 * new location
108 */
109 struct list_head pending[BTRFS_MAX_LEVEL];
110 /* list of backref nodes with no child node */
111 struct list_head leaves;
112 /* list of blocks that have been cowed in current transaction */
113 struct list_head changed;
114 /* list of detached backref node. */
115 struct list_head detached;
116
117 u64 last_trans;
118
119 int nr_nodes;
120 int nr_edges;
121 };
122
123 /*
124 * map address of tree root to tree
125 */
126 struct mapping_node {
127 struct rb_node rb_node;
128 u64 bytenr;
129 void *data;
130 };
131
132 struct mapping_tree {
133 struct rb_root rb_root;
134 spinlock_t lock;
135 };
136
137 /*
138 * present a tree block to process
139 */
140 struct tree_block {
141 struct rb_node rb_node;
142 u64 bytenr;
143 struct btrfs_key key;
144 unsigned int level:8;
145 unsigned int key_ready:1;
146 };
147
148 #define MAX_EXTENTS 128
149
150 struct file_extent_cluster {
151 u64 start;
152 u64 end;
153 u64 boundary[MAX_EXTENTS];
154 unsigned int nr;
155 };
156
157 struct reloc_control {
158 /* block group to relocate */
159 struct btrfs_block_group_cache *block_group;
160 /* extent tree */
161 struct btrfs_root *extent_root;
162 /* inode for moving data */
163 struct inode *data_inode;
164
165 struct btrfs_block_rsv *block_rsv;
166
167 struct backref_cache backref_cache;
168
169 struct file_extent_cluster cluster;
170 /* tree blocks have been processed */
171 struct extent_io_tree processed_blocks;
172 /* map start of tree root to corresponding reloc tree */
173 struct mapping_tree reloc_root_tree;
174 /* list of reloc trees */
175 struct list_head reloc_roots;
176 /* size of metadata reservation for merging reloc trees */
177 u64 merging_rsv_size;
178 /* size of relocated tree nodes */
179 u64 nodes_relocated;
180 /* reserved size for block group relocation*/
181 u64 reserved_bytes;
182
183 u64 search_start;
184 u64 extents_found;
185
186 unsigned int stage:8;
187 unsigned int create_reloc_tree:1;
188 unsigned int merge_reloc_tree:1;
189 unsigned int found_file_extent:1;
190 };
191
192 /* stages of data relocation */
193 #define MOVE_DATA_EXTENTS 0
194 #define UPDATE_DATA_PTRS 1
195
196 static void remove_backref_node(struct backref_cache *cache,
197 struct backref_node *node);
198 static void __mark_block_processed(struct reloc_control *rc,
199 struct backref_node *node);
200
201 static void mapping_tree_init(struct mapping_tree *tree)
202 {
203 tree->rb_root = RB_ROOT;
204 spin_lock_init(&tree->lock);
205 }
206
207 static void backref_cache_init(struct backref_cache *cache)
208 {
209 int i;
210 cache->rb_root = RB_ROOT;
211 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
212 INIT_LIST_HEAD(&cache->pending[i]);
213 INIT_LIST_HEAD(&cache->changed);
214 INIT_LIST_HEAD(&cache->detached);
215 INIT_LIST_HEAD(&cache->leaves);
216 }
217
218 static void backref_cache_cleanup(struct backref_cache *cache)
219 {
220 struct backref_node *node;
221 int i;
222
223 while (!list_empty(&cache->detached)) {
224 node = list_entry(cache->detached.next,
225 struct backref_node, list);
226 remove_backref_node(cache, node);
227 }
228
229 while (!list_empty(&cache->leaves)) {
230 node = list_entry(cache->leaves.next,
231 struct backref_node, lower);
232 remove_backref_node(cache, node);
233 }
234
235 cache->last_trans = 0;
236
237 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
238 BUG_ON(!list_empty(&cache->pending[i]));
239 BUG_ON(!list_empty(&cache->changed));
240 BUG_ON(!list_empty(&cache->detached));
241 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
242 BUG_ON(cache->nr_nodes);
243 BUG_ON(cache->nr_edges);
244 }
245
246 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
247 {
248 struct backref_node *node;
249
250 node = kzalloc(sizeof(*node), GFP_NOFS);
251 if (node) {
252 INIT_LIST_HEAD(&node->list);
253 INIT_LIST_HEAD(&node->upper);
254 INIT_LIST_HEAD(&node->lower);
255 RB_CLEAR_NODE(&node->rb_node);
256 cache->nr_nodes++;
257 }
258 return node;
259 }
260
261 static void free_backref_node(struct backref_cache *cache,
262 struct backref_node *node)
263 {
264 if (node) {
265 cache->nr_nodes--;
266 kfree(node);
267 }
268 }
269
270 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
271 {
272 struct backref_edge *edge;
273
274 edge = kzalloc(sizeof(*edge), GFP_NOFS);
275 if (edge)
276 cache->nr_edges++;
277 return edge;
278 }
279
280 static void free_backref_edge(struct backref_cache *cache,
281 struct backref_edge *edge)
282 {
283 if (edge) {
284 cache->nr_edges--;
285 kfree(edge);
286 }
287 }
288
289 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
290 struct rb_node *node)
291 {
292 struct rb_node **p = &root->rb_node;
293 struct rb_node *parent = NULL;
294 struct tree_entry *entry;
295
296 while (*p) {
297 parent = *p;
298 entry = rb_entry(parent, struct tree_entry, rb_node);
299
300 if (bytenr < entry->bytenr)
301 p = &(*p)->rb_left;
302 else if (bytenr > entry->bytenr)
303 p = &(*p)->rb_right;
304 else
305 return parent;
306 }
307
308 rb_link_node(node, parent, p);
309 rb_insert_color(node, root);
310 return NULL;
311 }
312
313 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
314 {
315 struct rb_node *n = root->rb_node;
316 struct tree_entry *entry;
317
318 while (n) {
319 entry = rb_entry(n, struct tree_entry, rb_node);
320
321 if (bytenr < entry->bytenr)
322 n = n->rb_left;
323 else if (bytenr > entry->bytenr)
324 n = n->rb_right;
325 else
326 return n;
327 }
328 return NULL;
329 }
330
331 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
332 {
333
334 struct btrfs_fs_info *fs_info = NULL;
335 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
336 rb_node);
337 if (bnode->root)
338 fs_info = bnode->root->fs_info;
339 btrfs_panic(fs_info, errno, "Inconsistency in backref cache "
340 "found at offset %llu", bytenr);
341 }
342
343 /*
344 * walk up backref nodes until reach node presents tree root
345 */
346 static struct backref_node *walk_up_backref(struct backref_node *node,
347 struct backref_edge *edges[],
348 int *index)
349 {
350 struct backref_edge *edge;
351 int idx = *index;
352
353 while (!list_empty(&node->upper)) {
354 edge = list_entry(node->upper.next,
355 struct backref_edge, list[LOWER]);
356 edges[idx++] = edge;
357 node = edge->node[UPPER];
358 }
359 BUG_ON(node->detached);
360 *index = idx;
361 return node;
362 }
363
364 /*
365 * walk down backref nodes to find start of next reference path
366 */
367 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
368 int *index)
369 {
370 struct backref_edge *edge;
371 struct backref_node *lower;
372 int idx = *index;
373
374 while (idx > 0) {
375 edge = edges[idx - 1];
376 lower = edge->node[LOWER];
377 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
378 idx--;
379 continue;
380 }
381 edge = list_entry(edge->list[LOWER].next,
382 struct backref_edge, list[LOWER]);
383 edges[idx - 1] = edge;
384 *index = idx;
385 return edge->node[UPPER];
386 }
387 *index = 0;
388 return NULL;
389 }
390
391 static void unlock_node_buffer(struct backref_node *node)
392 {
393 if (node->locked) {
394 btrfs_tree_unlock(node->eb);
395 node->locked = 0;
396 }
397 }
398
399 static void drop_node_buffer(struct backref_node *node)
400 {
401 if (node->eb) {
402 unlock_node_buffer(node);
403 free_extent_buffer(node->eb);
404 node->eb = NULL;
405 }
406 }
407
408 static void drop_backref_node(struct backref_cache *tree,
409 struct backref_node *node)
410 {
411 BUG_ON(!list_empty(&node->upper));
412
413 drop_node_buffer(node);
414 list_del(&node->list);
415 list_del(&node->lower);
416 if (!RB_EMPTY_NODE(&node->rb_node))
417 rb_erase(&node->rb_node, &tree->rb_root);
418 free_backref_node(tree, node);
419 }
420
421 /*
422 * remove a backref node from the backref cache
423 */
424 static void remove_backref_node(struct backref_cache *cache,
425 struct backref_node *node)
426 {
427 struct backref_node *upper;
428 struct backref_edge *edge;
429
430 if (!node)
431 return;
432
433 BUG_ON(!node->lowest && !node->detached);
434 while (!list_empty(&node->upper)) {
435 edge = list_entry(node->upper.next, struct backref_edge,
436 list[LOWER]);
437 upper = edge->node[UPPER];
438 list_del(&edge->list[LOWER]);
439 list_del(&edge->list[UPPER]);
440 free_backref_edge(cache, edge);
441
442 if (RB_EMPTY_NODE(&upper->rb_node)) {
443 BUG_ON(!list_empty(&node->upper));
444 drop_backref_node(cache, node);
445 node = upper;
446 node->lowest = 1;
447 continue;
448 }
449 /*
450 * add the node to leaf node list if no other
451 * child block cached.
452 */
453 if (list_empty(&upper->lower)) {
454 list_add_tail(&upper->lower, &cache->leaves);
455 upper->lowest = 1;
456 }
457 }
458
459 drop_backref_node(cache, node);
460 }
461
462 static void update_backref_node(struct backref_cache *cache,
463 struct backref_node *node, u64 bytenr)
464 {
465 struct rb_node *rb_node;
466 rb_erase(&node->rb_node, &cache->rb_root);
467 node->bytenr = bytenr;
468 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
469 if (rb_node)
470 backref_tree_panic(rb_node, -EEXIST, bytenr);
471 }
472
473 /*
474 * update backref cache after a transaction commit
475 */
476 static int update_backref_cache(struct btrfs_trans_handle *trans,
477 struct backref_cache *cache)
478 {
479 struct backref_node *node;
480 int level = 0;
481
482 if (cache->last_trans == 0) {
483 cache->last_trans = trans->transid;
484 return 0;
485 }
486
487 if (cache->last_trans == trans->transid)
488 return 0;
489
490 /*
491 * detached nodes are used to avoid unnecessary backref
492 * lookup. transaction commit changes the extent tree.
493 * so the detached nodes are no longer useful.
494 */
495 while (!list_empty(&cache->detached)) {
496 node = list_entry(cache->detached.next,
497 struct backref_node, list);
498 remove_backref_node(cache, node);
499 }
500
501 while (!list_empty(&cache->changed)) {
502 node = list_entry(cache->changed.next,
503 struct backref_node, list);
504 list_del_init(&node->list);
505 BUG_ON(node->pending);
506 update_backref_node(cache, node, node->new_bytenr);
507 }
508
509 /*
510 * some nodes can be left in the pending list if there were
511 * errors during processing the pending nodes.
512 */
513 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
514 list_for_each_entry(node, &cache->pending[level], list) {
515 BUG_ON(!node->pending);
516 if (node->bytenr == node->new_bytenr)
517 continue;
518 update_backref_node(cache, node, node->new_bytenr);
519 }
520 }
521
522 cache->last_trans = 0;
523 return 1;
524 }
525
526
527 static int should_ignore_root(struct btrfs_root *root)
528 {
529 struct btrfs_root *reloc_root;
530
531 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
532 return 0;
533
534 reloc_root = root->reloc_root;
535 if (!reloc_root)
536 return 0;
537
538 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
539 root->fs_info->running_transaction->transid - 1)
540 return 0;
541 /*
542 * if there is reloc tree and it was created in previous
543 * transaction backref lookup can find the reloc tree,
544 * so backref node for the fs tree root is useless for
545 * relocation.
546 */
547 return 1;
548 }
549 /*
550 * find reloc tree by address of tree root
551 */
552 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
553 u64 bytenr)
554 {
555 struct rb_node *rb_node;
556 struct mapping_node *node;
557 struct btrfs_root *root = NULL;
558
559 spin_lock(&rc->reloc_root_tree.lock);
560 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
561 if (rb_node) {
562 node = rb_entry(rb_node, struct mapping_node, rb_node);
563 root = (struct btrfs_root *)node->data;
564 }
565 spin_unlock(&rc->reloc_root_tree.lock);
566 return root;
567 }
568
569 static int is_cowonly_root(u64 root_objectid)
570 {
571 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
572 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
573 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
574 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
575 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
576 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
577 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
578 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
579 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
580 return 1;
581 return 0;
582 }
583
584 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
585 u64 root_objectid)
586 {
587 struct btrfs_key key;
588
589 key.objectid = root_objectid;
590 key.type = BTRFS_ROOT_ITEM_KEY;
591 if (is_cowonly_root(root_objectid))
592 key.offset = 0;
593 else
594 key.offset = (u64)-1;
595
596 return btrfs_get_fs_root(fs_info, &key, false);
597 }
598
599 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
600 static noinline_for_stack
601 struct btrfs_root *find_tree_root(struct reloc_control *rc,
602 struct extent_buffer *leaf,
603 struct btrfs_extent_ref_v0 *ref0)
604 {
605 struct btrfs_root *root;
606 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
607 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
608
609 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
610
611 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
612 BUG_ON(IS_ERR(root));
613
614 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
615 generation != btrfs_root_generation(&root->root_item))
616 return NULL;
617
618 return root;
619 }
620 #endif
621
622 static noinline_for_stack
623 int find_inline_backref(struct extent_buffer *leaf, int slot,
624 unsigned long *ptr, unsigned long *end)
625 {
626 struct btrfs_key key;
627 struct btrfs_extent_item *ei;
628 struct btrfs_tree_block_info *bi;
629 u32 item_size;
630
631 btrfs_item_key_to_cpu(leaf, &key, slot);
632
633 item_size = btrfs_item_size_nr(leaf, slot);
634 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
635 if (item_size < sizeof(*ei)) {
636 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
637 return 1;
638 }
639 #endif
640 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
641 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
642 BTRFS_EXTENT_FLAG_TREE_BLOCK));
643
644 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
645 item_size <= sizeof(*ei) + sizeof(*bi)) {
646 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
647 return 1;
648 }
649 if (key.type == BTRFS_METADATA_ITEM_KEY &&
650 item_size <= sizeof(*ei)) {
651 WARN_ON(item_size < sizeof(*ei));
652 return 1;
653 }
654
655 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
656 bi = (struct btrfs_tree_block_info *)(ei + 1);
657 *ptr = (unsigned long)(bi + 1);
658 } else {
659 *ptr = (unsigned long)(ei + 1);
660 }
661 *end = (unsigned long)ei + item_size;
662 return 0;
663 }
664
665 /*
666 * build backref tree for a given tree block. root of the backref tree
667 * corresponds the tree block, leaves of the backref tree correspond
668 * roots of b-trees that reference the tree block.
669 *
670 * the basic idea of this function is check backrefs of a given block
671 * to find upper level blocks that refernece the block, and then check
672 * bakcrefs of these upper level blocks recursively. the recursion stop
673 * when tree root is reached or backrefs for the block is cached.
674 *
675 * NOTE: if we find backrefs for a block are cached, we know backrefs
676 * for all upper level blocks that directly/indirectly reference the
677 * block are also cached.
678 */
679 static noinline_for_stack
680 struct backref_node *build_backref_tree(struct reloc_control *rc,
681 struct btrfs_key *node_key,
682 int level, u64 bytenr)
683 {
684 struct backref_cache *cache = &rc->backref_cache;
685 struct btrfs_path *path1;
686 struct btrfs_path *path2;
687 struct extent_buffer *eb;
688 struct btrfs_root *root;
689 struct backref_node *cur;
690 struct backref_node *upper;
691 struct backref_node *lower;
692 struct backref_node *node = NULL;
693 struct backref_node *exist = NULL;
694 struct backref_edge *edge;
695 struct rb_node *rb_node;
696 struct btrfs_key key;
697 unsigned long end;
698 unsigned long ptr;
699 LIST_HEAD(list);
700 LIST_HEAD(useless);
701 int cowonly;
702 int ret;
703 int err = 0;
704 bool need_check = true;
705
706 path1 = btrfs_alloc_path();
707 path2 = btrfs_alloc_path();
708 if (!path1 || !path2) {
709 err = -ENOMEM;
710 goto out;
711 }
712 path1->reada = READA_FORWARD;
713 path2->reada = READA_FORWARD;
714
715 node = alloc_backref_node(cache);
716 if (!node) {
717 err = -ENOMEM;
718 goto out;
719 }
720
721 node->bytenr = bytenr;
722 node->level = level;
723 node->lowest = 1;
724 cur = node;
725 again:
726 end = 0;
727 ptr = 0;
728 key.objectid = cur->bytenr;
729 key.type = BTRFS_METADATA_ITEM_KEY;
730 key.offset = (u64)-1;
731
732 path1->search_commit_root = 1;
733 path1->skip_locking = 1;
734 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
735 0, 0);
736 if (ret < 0) {
737 err = ret;
738 goto out;
739 }
740 ASSERT(ret);
741 ASSERT(path1->slots[0]);
742
743 path1->slots[0]--;
744
745 WARN_ON(cur->checked);
746 if (!list_empty(&cur->upper)) {
747 /*
748 * the backref was added previously when processing
749 * backref of type BTRFS_TREE_BLOCK_REF_KEY
750 */
751 ASSERT(list_is_singular(&cur->upper));
752 edge = list_entry(cur->upper.next, struct backref_edge,
753 list[LOWER]);
754 ASSERT(list_empty(&edge->list[UPPER]));
755 exist = edge->node[UPPER];
756 /*
757 * add the upper level block to pending list if we need
758 * check its backrefs
759 */
760 if (!exist->checked)
761 list_add_tail(&edge->list[UPPER], &list);
762 } else {
763 exist = NULL;
764 }
765
766 while (1) {
767 cond_resched();
768 eb = path1->nodes[0];
769
770 if (ptr >= end) {
771 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
772 ret = btrfs_next_leaf(rc->extent_root, path1);
773 if (ret < 0) {
774 err = ret;
775 goto out;
776 }
777 if (ret > 0)
778 break;
779 eb = path1->nodes[0];
780 }
781
782 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
783 if (key.objectid != cur->bytenr) {
784 WARN_ON(exist);
785 break;
786 }
787
788 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
789 key.type == BTRFS_METADATA_ITEM_KEY) {
790 ret = find_inline_backref(eb, path1->slots[0],
791 &ptr, &end);
792 if (ret)
793 goto next;
794 }
795 }
796
797 if (ptr < end) {
798 /* update key for inline back ref */
799 struct btrfs_extent_inline_ref *iref;
800 iref = (struct btrfs_extent_inline_ref *)ptr;
801 key.type = btrfs_extent_inline_ref_type(eb, iref);
802 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
803 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
804 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
805 }
806
807 if (exist &&
808 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
809 exist->owner == key.offset) ||
810 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
811 exist->bytenr == key.offset))) {
812 exist = NULL;
813 goto next;
814 }
815
816 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
817 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
818 key.type == BTRFS_EXTENT_REF_V0_KEY) {
819 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
820 struct btrfs_extent_ref_v0 *ref0;
821 ref0 = btrfs_item_ptr(eb, path1->slots[0],
822 struct btrfs_extent_ref_v0);
823 if (key.objectid == key.offset) {
824 root = find_tree_root(rc, eb, ref0);
825 if (root && !should_ignore_root(root))
826 cur->root = root;
827 else
828 list_add(&cur->list, &useless);
829 break;
830 }
831 if (is_cowonly_root(btrfs_ref_root_v0(eb,
832 ref0)))
833 cur->cowonly = 1;
834 }
835 #else
836 ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
837 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
838 #endif
839 if (key.objectid == key.offset) {
840 /*
841 * only root blocks of reloc trees use
842 * backref of this type.
843 */
844 root = find_reloc_root(rc, cur->bytenr);
845 ASSERT(root);
846 cur->root = root;
847 break;
848 }
849
850 edge = alloc_backref_edge(cache);
851 if (!edge) {
852 err = -ENOMEM;
853 goto out;
854 }
855 rb_node = tree_search(&cache->rb_root, key.offset);
856 if (!rb_node) {
857 upper = alloc_backref_node(cache);
858 if (!upper) {
859 free_backref_edge(cache, edge);
860 err = -ENOMEM;
861 goto out;
862 }
863 upper->bytenr = key.offset;
864 upper->level = cur->level + 1;
865 /*
866 * backrefs for the upper level block isn't
867 * cached, add the block to pending list
868 */
869 list_add_tail(&edge->list[UPPER], &list);
870 } else {
871 upper = rb_entry(rb_node, struct backref_node,
872 rb_node);
873 ASSERT(upper->checked);
874 INIT_LIST_HEAD(&edge->list[UPPER]);
875 }
876 list_add_tail(&edge->list[LOWER], &cur->upper);
877 edge->node[LOWER] = cur;
878 edge->node[UPPER] = upper;
879
880 goto next;
881 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
882 goto next;
883 }
884
885 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
886 root = read_fs_root(rc->extent_root->fs_info, key.offset);
887 if (IS_ERR(root)) {
888 err = PTR_ERR(root);
889 goto out;
890 }
891
892 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
893 cur->cowonly = 1;
894
895 if (btrfs_root_level(&root->root_item) == cur->level) {
896 /* tree root */
897 ASSERT(btrfs_root_bytenr(&root->root_item) ==
898 cur->bytenr);
899 if (should_ignore_root(root))
900 list_add(&cur->list, &useless);
901 else
902 cur->root = root;
903 break;
904 }
905
906 level = cur->level + 1;
907
908 /*
909 * searching the tree to find upper level blocks
910 * reference the block.
911 */
912 path2->search_commit_root = 1;
913 path2->skip_locking = 1;
914 path2->lowest_level = level;
915 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
916 path2->lowest_level = 0;
917 if (ret < 0) {
918 err = ret;
919 goto out;
920 }
921 if (ret > 0 && path2->slots[level] > 0)
922 path2->slots[level]--;
923
924 eb = path2->nodes[level];
925 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
926 cur->bytenr);
927
928 lower = cur;
929 need_check = true;
930 for (; level < BTRFS_MAX_LEVEL; level++) {
931 if (!path2->nodes[level]) {
932 ASSERT(btrfs_root_bytenr(&root->root_item) ==
933 lower->bytenr);
934 if (should_ignore_root(root))
935 list_add(&lower->list, &useless);
936 else
937 lower->root = root;
938 break;
939 }
940
941 edge = alloc_backref_edge(cache);
942 if (!edge) {
943 err = -ENOMEM;
944 goto out;
945 }
946
947 eb = path2->nodes[level];
948 rb_node = tree_search(&cache->rb_root, eb->start);
949 if (!rb_node) {
950 upper = alloc_backref_node(cache);
951 if (!upper) {
952 free_backref_edge(cache, edge);
953 err = -ENOMEM;
954 goto out;
955 }
956 upper->bytenr = eb->start;
957 upper->owner = btrfs_header_owner(eb);
958 upper->level = lower->level + 1;
959 if (!test_bit(BTRFS_ROOT_REF_COWS,
960 &root->state))
961 upper->cowonly = 1;
962
963 /*
964 * if we know the block isn't shared
965 * we can void checking its backrefs.
966 */
967 if (btrfs_block_can_be_shared(root, eb))
968 upper->checked = 0;
969 else
970 upper->checked = 1;
971
972 /*
973 * add the block to pending list if we
974 * need check its backrefs, we only do this once
975 * while walking up a tree as we will catch
976 * anything else later on.
977 */
978 if (!upper->checked && need_check) {
979 need_check = false;
980 list_add_tail(&edge->list[UPPER],
981 &list);
982 } else {
983 if (upper->checked)
984 need_check = true;
985 INIT_LIST_HEAD(&edge->list[UPPER]);
986 }
987 } else {
988 upper = rb_entry(rb_node, struct backref_node,
989 rb_node);
990 ASSERT(upper->checked);
991 INIT_LIST_HEAD(&edge->list[UPPER]);
992 if (!upper->owner)
993 upper->owner = btrfs_header_owner(eb);
994 }
995 list_add_tail(&edge->list[LOWER], &lower->upper);
996 edge->node[LOWER] = lower;
997 edge->node[UPPER] = upper;
998
999 if (rb_node)
1000 break;
1001 lower = upper;
1002 upper = NULL;
1003 }
1004 btrfs_release_path(path2);
1005 next:
1006 if (ptr < end) {
1007 ptr += btrfs_extent_inline_ref_size(key.type);
1008 if (ptr >= end) {
1009 WARN_ON(ptr > end);
1010 ptr = 0;
1011 end = 0;
1012 }
1013 }
1014 if (ptr >= end)
1015 path1->slots[0]++;
1016 }
1017 btrfs_release_path(path1);
1018
1019 cur->checked = 1;
1020 WARN_ON(exist);
1021
1022 /* the pending list isn't empty, take the first block to process */
1023 if (!list_empty(&list)) {
1024 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1025 list_del_init(&edge->list[UPPER]);
1026 cur = edge->node[UPPER];
1027 goto again;
1028 }
1029
1030 /*
1031 * everything goes well, connect backref nodes and insert backref nodes
1032 * into the cache.
1033 */
1034 ASSERT(node->checked);
1035 cowonly = node->cowonly;
1036 if (!cowonly) {
1037 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1038 &node->rb_node);
1039 if (rb_node)
1040 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1041 list_add_tail(&node->lower, &cache->leaves);
1042 }
1043
1044 list_for_each_entry(edge, &node->upper, list[LOWER])
1045 list_add_tail(&edge->list[UPPER], &list);
1046
1047 while (!list_empty(&list)) {
1048 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1049 list_del_init(&edge->list[UPPER]);
1050 upper = edge->node[UPPER];
1051 if (upper->detached) {
1052 list_del(&edge->list[LOWER]);
1053 lower = edge->node[LOWER];
1054 free_backref_edge(cache, edge);
1055 if (list_empty(&lower->upper))
1056 list_add(&lower->list, &useless);
1057 continue;
1058 }
1059
1060 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1061 if (upper->lowest) {
1062 list_del_init(&upper->lower);
1063 upper->lowest = 0;
1064 }
1065
1066 list_add_tail(&edge->list[UPPER], &upper->lower);
1067 continue;
1068 }
1069
1070 if (!upper->checked) {
1071 /*
1072 * Still want to blow up for developers since this is a
1073 * logic bug.
1074 */
1075 ASSERT(0);
1076 err = -EINVAL;
1077 goto out;
1078 }
1079 if (cowonly != upper->cowonly) {
1080 ASSERT(0);
1081 err = -EINVAL;
1082 goto out;
1083 }
1084
1085 if (!cowonly) {
1086 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1087 &upper->rb_node);
1088 if (rb_node)
1089 backref_tree_panic(rb_node, -EEXIST,
1090 upper->bytenr);
1091 }
1092
1093 list_add_tail(&edge->list[UPPER], &upper->lower);
1094
1095 list_for_each_entry(edge, &upper->upper, list[LOWER])
1096 list_add_tail(&edge->list[UPPER], &list);
1097 }
1098 /*
1099 * process useless backref nodes. backref nodes for tree leaves
1100 * are deleted from the cache. backref nodes for upper level
1101 * tree blocks are left in the cache to avoid unnecessary backref
1102 * lookup.
1103 */
1104 while (!list_empty(&useless)) {
1105 upper = list_entry(useless.next, struct backref_node, list);
1106 list_del_init(&upper->list);
1107 ASSERT(list_empty(&upper->upper));
1108 if (upper == node)
1109 node = NULL;
1110 if (upper->lowest) {
1111 list_del_init(&upper->lower);
1112 upper->lowest = 0;
1113 }
1114 while (!list_empty(&upper->lower)) {
1115 edge = list_entry(upper->lower.next,
1116 struct backref_edge, list[UPPER]);
1117 list_del(&edge->list[UPPER]);
1118 list_del(&edge->list[LOWER]);
1119 lower = edge->node[LOWER];
1120 free_backref_edge(cache, edge);
1121
1122 if (list_empty(&lower->upper))
1123 list_add(&lower->list, &useless);
1124 }
1125 __mark_block_processed(rc, upper);
1126 if (upper->level > 0) {
1127 list_add(&upper->list, &cache->detached);
1128 upper->detached = 1;
1129 } else {
1130 rb_erase(&upper->rb_node, &cache->rb_root);
1131 free_backref_node(cache, upper);
1132 }
1133 }
1134 out:
1135 btrfs_free_path(path1);
1136 btrfs_free_path(path2);
1137 if (err) {
1138 while (!list_empty(&useless)) {
1139 lower = list_entry(useless.next,
1140 struct backref_node, list);
1141 list_del_init(&lower->list);
1142 }
1143 while (!list_empty(&list)) {
1144 edge = list_first_entry(&list, struct backref_edge,
1145 list[UPPER]);
1146 list_del(&edge->list[UPPER]);
1147 list_del(&edge->list[LOWER]);
1148 lower = edge->node[LOWER];
1149 upper = edge->node[UPPER];
1150 free_backref_edge(cache, edge);
1151
1152 /*
1153 * Lower is no longer linked to any upper backref nodes
1154 * and isn't in the cache, we can free it ourselves.
1155 */
1156 if (list_empty(&lower->upper) &&
1157 RB_EMPTY_NODE(&lower->rb_node))
1158 list_add(&lower->list, &useless);
1159
1160 if (!RB_EMPTY_NODE(&upper->rb_node))
1161 continue;
1162
1163 /* Add this guy's upper edges to the list to proces */
1164 list_for_each_entry(edge, &upper->upper, list[LOWER])
1165 list_add_tail(&edge->list[UPPER], &list);
1166 if (list_empty(&upper->upper))
1167 list_add(&upper->list, &useless);
1168 }
1169
1170 while (!list_empty(&useless)) {
1171 lower = list_entry(useless.next,
1172 struct backref_node, list);
1173 list_del_init(&lower->list);
1174 free_backref_node(cache, lower);
1175 }
1176 return ERR_PTR(err);
1177 }
1178 ASSERT(!node || !node->detached);
1179 return node;
1180 }
1181
1182 /*
1183 * helper to add backref node for the newly created snapshot.
1184 * the backref node is created by cloning backref node that
1185 * corresponds to root of source tree
1186 */
1187 static int clone_backref_node(struct btrfs_trans_handle *trans,
1188 struct reloc_control *rc,
1189 struct btrfs_root *src,
1190 struct btrfs_root *dest)
1191 {
1192 struct btrfs_root *reloc_root = src->reloc_root;
1193 struct backref_cache *cache = &rc->backref_cache;
1194 struct backref_node *node = NULL;
1195 struct backref_node *new_node;
1196 struct backref_edge *edge;
1197 struct backref_edge *new_edge;
1198 struct rb_node *rb_node;
1199
1200 if (cache->last_trans > 0)
1201 update_backref_cache(trans, cache);
1202
1203 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1204 if (rb_node) {
1205 node = rb_entry(rb_node, struct backref_node, rb_node);
1206 if (node->detached)
1207 node = NULL;
1208 else
1209 BUG_ON(node->new_bytenr != reloc_root->node->start);
1210 }
1211
1212 if (!node) {
1213 rb_node = tree_search(&cache->rb_root,
1214 reloc_root->commit_root->start);
1215 if (rb_node) {
1216 node = rb_entry(rb_node, struct backref_node,
1217 rb_node);
1218 BUG_ON(node->detached);
1219 }
1220 }
1221
1222 if (!node)
1223 return 0;
1224
1225 new_node = alloc_backref_node(cache);
1226 if (!new_node)
1227 return -ENOMEM;
1228
1229 new_node->bytenr = dest->node->start;
1230 new_node->level = node->level;
1231 new_node->lowest = node->lowest;
1232 new_node->checked = 1;
1233 new_node->root = dest;
1234
1235 if (!node->lowest) {
1236 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1237 new_edge = alloc_backref_edge(cache);
1238 if (!new_edge)
1239 goto fail;
1240
1241 new_edge->node[UPPER] = new_node;
1242 new_edge->node[LOWER] = edge->node[LOWER];
1243 list_add_tail(&new_edge->list[UPPER],
1244 &new_node->lower);
1245 }
1246 } else {
1247 list_add_tail(&new_node->lower, &cache->leaves);
1248 }
1249
1250 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1251 &new_node->rb_node);
1252 if (rb_node)
1253 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1254
1255 if (!new_node->lowest) {
1256 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1257 list_add_tail(&new_edge->list[LOWER],
1258 &new_edge->node[LOWER]->upper);
1259 }
1260 }
1261 return 0;
1262 fail:
1263 while (!list_empty(&new_node->lower)) {
1264 new_edge = list_entry(new_node->lower.next,
1265 struct backref_edge, list[UPPER]);
1266 list_del(&new_edge->list[UPPER]);
1267 free_backref_edge(cache, new_edge);
1268 }
1269 free_backref_node(cache, new_node);
1270 return -ENOMEM;
1271 }
1272
1273 /*
1274 * helper to add 'address of tree root -> reloc tree' mapping
1275 */
1276 static int __must_check __add_reloc_root(struct btrfs_root *root)
1277 {
1278 struct rb_node *rb_node;
1279 struct mapping_node *node;
1280 struct reloc_control *rc = root->fs_info->reloc_ctl;
1281
1282 node = kmalloc(sizeof(*node), GFP_NOFS);
1283 if (!node)
1284 return -ENOMEM;
1285
1286 node->bytenr = root->node->start;
1287 node->data = root;
1288
1289 spin_lock(&rc->reloc_root_tree.lock);
1290 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1291 node->bytenr, &node->rb_node);
1292 spin_unlock(&rc->reloc_root_tree.lock);
1293 if (rb_node) {
1294 btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
1295 "for start=%llu while inserting into relocation "
1296 "tree", node->bytenr);
1297 kfree(node);
1298 return -EEXIST;
1299 }
1300
1301 list_add_tail(&root->root_list, &rc->reloc_roots);
1302 return 0;
1303 }
1304
1305 /*
1306 * helper to delete the 'address of tree root -> reloc tree'
1307 * mapping
1308 */
1309 static void __del_reloc_root(struct btrfs_root *root)
1310 {
1311 struct rb_node *rb_node;
1312 struct mapping_node *node = NULL;
1313 struct reloc_control *rc = root->fs_info->reloc_ctl;
1314
1315 spin_lock(&rc->reloc_root_tree.lock);
1316 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1317 root->node->start);
1318 if (rb_node) {
1319 node = rb_entry(rb_node, struct mapping_node, rb_node);
1320 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1321 }
1322 spin_unlock(&rc->reloc_root_tree.lock);
1323
1324 if (!node)
1325 return;
1326 BUG_ON((struct btrfs_root *)node->data != root);
1327
1328 spin_lock(&root->fs_info->trans_lock);
1329 list_del_init(&root->root_list);
1330 spin_unlock(&root->fs_info->trans_lock);
1331 kfree(node);
1332 }
1333
1334 /*
1335 * helper to update the 'address of tree root -> reloc tree'
1336 * mapping
1337 */
1338 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1339 {
1340 struct rb_node *rb_node;
1341 struct mapping_node *node = NULL;
1342 struct reloc_control *rc = root->fs_info->reloc_ctl;
1343
1344 spin_lock(&rc->reloc_root_tree.lock);
1345 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1346 root->node->start);
1347 if (rb_node) {
1348 node = rb_entry(rb_node, struct mapping_node, rb_node);
1349 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1350 }
1351 spin_unlock(&rc->reloc_root_tree.lock);
1352
1353 if (!node)
1354 return 0;
1355 BUG_ON((struct btrfs_root *)node->data != root);
1356
1357 spin_lock(&rc->reloc_root_tree.lock);
1358 node->bytenr = new_bytenr;
1359 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1360 node->bytenr, &node->rb_node);
1361 spin_unlock(&rc->reloc_root_tree.lock);
1362 if (rb_node)
1363 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1364 return 0;
1365 }
1366
1367 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1368 struct btrfs_root *root, u64 objectid)
1369 {
1370 struct btrfs_root *reloc_root;
1371 struct extent_buffer *eb;
1372 struct btrfs_root_item *root_item;
1373 struct btrfs_key root_key;
1374 u64 last_snap = 0;
1375 int ret;
1376
1377 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1378 BUG_ON(!root_item);
1379
1380 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1381 root_key.type = BTRFS_ROOT_ITEM_KEY;
1382 root_key.offset = objectid;
1383
1384 if (root->root_key.objectid == objectid) {
1385 /* called by btrfs_init_reloc_root */
1386 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1387 BTRFS_TREE_RELOC_OBJECTID);
1388 BUG_ON(ret);
1389
1390 last_snap = btrfs_root_last_snapshot(&root->root_item);
1391 btrfs_set_root_last_snapshot(&root->root_item,
1392 trans->transid - 1);
1393 } else {
1394 /*
1395 * called by btrfs_reloc_post_snapshot_hook.
1396 * the source tree is a reloc tree, all tree blocks
1397 * modified after it was created have RELOC flag
1398 * set in their headers. so it's OK to not update
1399 * the 'last_snapshot'.
1400 */
1401 ret = btrfs_copy_root(trans, root, root->node, &eb,
1402 BTRFS_TREE_RELOC_OBJECTID);
1403 BUG_ON(ret);
1404 }
1405
1406 memcpy(root_item, &root->root_item, sizeof(*root_item));
1407 btrfs_set_root_bytenr(root_item, eb->start);
1408 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1409 btrfs_set_root_generation(root_item, trans->transid);
1410
1411 if (root->root_key.objectid == objectid) {
1412 btrfs_set_root_refs(root_item, 0);
1413 memset(&root_item->drop_progress, 0,
1414 sizeof(struct btrfs_disk_key));
1415 root_item->drop_level = 0;
1416 /*
1417 * abuse rtransid, it is safe because it is impossible to
1418 * receive data into a relocation tree.
1419 */
1420 btrfs_set_root_rtransid(root_item, last_snap);
1421 btrfs_set_root_otransid(root_item, trans->transid);
1422 }
1423
1424 btrfs_tree_unlock(eb);
1425 free_extent_buffer(eb);
1426
1427 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1428 &root_key, root_item);
1429 BUG_ON(ret);
1430 kfree(root_item);
1431
1432 reloc_root = btrfs_read_fs_root(root->fs_info->tree_root, &root_key);
1433 BUG_ON(IS_ERR(reloc_root));
1434 reloc_root->last_trans = trans->transid;
1435 return reloc_root;
1436 }
1437
1438 /*
1439 * create reloc tree for a given fs tree. reloc tree is just a
1440 * snapshot of the fs tree with special root objectid.
1441 */
1442 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1443 struct btrfs_root *root)
1444 {
1445 struct btrfs_root *reloc_root;
1446 struct reloc_control *rc = root->fs_info->reloc_ctl;
1447 struct btrfs_block_rsv *rsv;
1448 int clear_rsv = 0;
1449 int ret;
1450
1451 if (root->reloc_root) {
1452 reloc_root = root->reloc_root;
1453 reloc_root->last_trans = trans->transid;
1454 return 0;
1455 }
1456
1457 if (!rc || !rc->create_reloc_tree ||
1458 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1459 return 0;
1460
1461 if (!trans->reloc_reserved) {
1462 rsv = trans->block_rsv;
1463 trans->block_rsv = rc->block_rsv;
1464 clear_rsv = 1;
1465 }
1466 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1467 if (clear_rsv)
1468 trans->block_rsv = rsv;
1469
1470 ret = __add_reloc_root(reloc_root);
1471 BUG_ON(ret < 0);
1472 root->reloc_root = reloc_root;
1473 return 0;
1474 }
1475
1476 /*
1477 * update root item of reloc tree
1478 */
1479 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1480 struct btrfs_root *root)
1481 {
1482 struct btrfs_root *reloc_root;
1483 struct btrfs_root_item *root_item;
1484 int ret;
1485
1486 if (!root->reloc_root)
1487 goto out;
1488
1489 reloc_root = root->reloc_root;
1490 root_item = &reloc_root->root_item;
1491
1492 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1493 btrfs_root_refs(root_item) == 0) {
1494 root->reloc_root = NULL;
1495 __del_reloc_root(reloc_root);
1496 }
1497
1498 if (reloc_root->commit_root != reloc_root->node) {
1499 btrfs_set_root_node(root_item, reloc_root->node);
1500 free_extent_buffer(reloc_root->commit_root);
1501 reloc_root->commit_root = btrfs_root_node(reloc_root);
1502 }
1503
1504 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1505 &reloc_root->root_key, root_item);
1506 BUG_ON(ret);
1507
1508 out:
1509 return 0;
1510 }
1511
1512 /*
1513 * helper to find first cached inode with inode number >= objectid
1514 * in a subvolume
1515 */
1516 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1517 {
1518 struct rb_node *node;
1519 struct rb_node *prev;
1520 struct btrfs_inode *entry;
1521 struct inode *inode;
1522
1523 spin_lock(&root->inode_lock);
1524 again:
1525 node = root->inode_tree.rb_node;
1526 prev = NULL;
1527 while (node) {
1528 prev = node;
1529 entry = rb_entry(node, struct btrfs_inode, rb_node);
1530
1531 if (objectid < btrfs_ino(&entry->vfs_inode))
1532 node = node->rb_left;
1533 else if (objectid > btrfs_ino(&entry->vfs_inode))
1534 node = node->rb_right;
1535 else
1536 break;
1537 }
1538 if (!node) {
1539 while (prev) {
1540 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1541 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1542 node = prev;
1543 break;
1544 }
1545 prev = rb_next(prev);
1546 }
1547 }
1548 while (node) {
1549 entry = rb_entry(node, struct btrfs_inode, rb_node);
1550 inode = igrab(&entry->vfs_inode);
1551 if (inode) {
1552 spin_unlock(&root->inode_lock);
1553 return inode;
1554 }
1555
1556 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1557 if (cond_resched_lock(&root->inode_lock))
1558 goto again;
1559
1560 node = rb_next(node);
1561 }
1562 spin_unlock(&root->inode_lock);
1563 return NULL;
1564 }
1565
1566 static int in_block_group(u64 bytenr,
1567 struct btrfs_block_group_cache *block_group)
1568 {
1569 if (bytenr >= block_group->key.objectid &&
1570 bytenr < block_group->key.objectid + block_group->key.offset)
1571 return 1;
1572 return 0;
1573 }
1574
1575 /*
1576 * get new location of data
1577 */
1578 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1579 u64 bytenr, u64 num_bytes)
1580 {
1581 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1582 struct btrfs_path *path;
1583 struct btrfs_file_extent_item *fi;
1584 struct extent_buffer *leaf;
1585 int ret;
1586
1587 path = btrfs_alloc_path();
1588 if (!path)
1589 return -ENOMEM;
1590
1591 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1592 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1593 bytenr, 0);
1594 if (ret < 0)
1595 goto out;
1596 if (ret > 0) {
1597 ret = -ENOENT;
1598 goto out;
1599 }
1600
1601 leaf = path->nodes[0];
1602 fi = btrfs_item_ptr(leaf, path->slots[0],
1603 struct btrfs_file_extent_item);
1604
1605 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1606 btrfs_file_extent_compression(leaf, fi) ||
1607 btrfs_file_extent_encryption(leaf, fi) ||
1608 btrfs_file_extent_other_encoding(leaf, fi));
1609
1610 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1611 ret = -EINVAL;
1612 goto out;
1613 }
1614
1615 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1616 ret = 0;
1617 out:
1618 btrfs_free_path(path);
1619 return ret;
1620 }
1621
1622 /*
1623 * update file extent items in the tree leaf to point to
1624 * the new locations.
1625 */
1626 static noinline_for_stack
1627 int replace_file_extents(struct btrfs_trans_handle *trans,
1628 struct reloc_control *rc,
1629 struct btrfs_root *root,
1630 struct extent_buffer *leaf)
1631 {
1632 struct btrfs_key key;
1633 struct btrfs_file_extent_item *fi;
1634 struct inode *inode = NULL;
1635 u64 parent;
1636 u64 bytenr;
1637 u64 new_bytenr = 0;
1638 u64 num_bytes;
1639 u64 end;
1640 u32 nritems;
1641 u32 i;
1642 int ret = 0;
1643 int first = 1;
1644 int dirty = 0;
1645
1646 if (rc->stage != UPDATE_DATA_PTRS)
1647 return 0;
1648
1649 /* reloc trees always use full backref */
1650 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1651 parent = leaf->start;
1652 else
1653 parent = 0;
1654
1655 nritems = btrfs_header_nritems(leaf);
1656 for (i = 0; i < nritems; i++) {
1657 cond_resched();
1658 btrfs_item_key_to_cpu(leaf, &key, i);
1659 if (key.type != BTRFS_EXTENT_DATA_KEY)
1660 continue;
1661 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1662 if (btrfs_file_extent_type(leaf, fi) ==
1663 BTRFS_FILE_EXTENT_INLINE)
1664 continue;
1665 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1666 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1667 if (bytenr == 0)
1668 continue;
1669 if (!in_block_group(bytenr, rc->block_group))
1670 continue;
1671
1672 /*
1673 * if we are modifying block in fs tree, wait for readpage
1674 * to complete and drop the extent cache
1675 */
1676 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1677 if (first) {
1678 inode = find_next_inode(root, key.objectid);
1679 first = 0;
1680 } else if (inode && btrfs_ino(inode) < key.objectid) {
1681 btrfs_add_delayed_iput(inode);
1682 inode = find_next_inode(root, key.objectid);
1683 }
1684 if (inode && btrfs_ino(inode) == key.objectid) {
1685 end = key.offset +
1686 btrfs_file_extent_num_bytes(leaf, fi);
1687 WARN_ON(!IS_ALIGNED(key.offset,
1688 root->sectorsize));
1689 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1690 end--;
1691 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1692 key.offset, end);
1693 if (!ret)
1694 continue;
1695
1696 btrfs_drop_extent_cache(inode, key.offset, end,
1697 1);
1698 unlock_extent(&BTRFS_I(inode)->io_tree,
1699 key.offset, end);
1700 }
1701 }
1702
1703 ret = get_new_location(rc->data_inode, &new_bytenr,
1704 bytenr, num_bytes);
1705 if (ret) {
1706 /*
1707 * Don't have to abort since we've not changed anything
1708 * in the file extent yet.
1709 */
1710 break;
1711 }
1712
1713 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1714 dirty = 1;
1715
1716 key.offset -= btrfs_file_extent_offset(leaf, fi);
1717 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1718 num_bytes, parent,
1719 btrfs_header_owner(leaf),
1720 key.objectid, key.offset);
1721 if (ret) {
1722 btrfs_abort_transaction(trans, root, ret);
1723 break;
1724 }
1725
1726 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1727 parent, btrfs_header_owner(leaf),
1728 key.objectid, key.offset);
1729 if (ret) {
1730 btrfs_abort_transaction(trans, root, ret);
1731 break;
1732 }
1733 }
1734 if (dirty)
1735 btrfs_mark_buffer_dirty(leaf);
1736 if (inode)
1737 btrfs_add_delayed_iput(inode);
1738 return ret;
1739 }
1740
1741 static noinline_for_stack
1742 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1743 struct btrfs_path *path, int level)
1744 {
1745 struct btrfs_disk_key key1;
1746 struct btrfs_disk_key key2;
1747 btrfs_node_key(eb, &key1, slot);
1748 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1749 return memcmp(&key1, &key2, sizeof(key1));
1750 }
1751
1752 /*
1753 * try to replace tree blocks in fs tree with the new blocks
1754 * in reloc tree. tree blocks haven't been modified since the
1755 * reloc tree was create can be replaced.
1756 *
1757 * if a block was replaced, level of the block + 1 is returned.
1758 * if no block got replaced, 0 is returned. if there are other
1759 * errors, a negative error number is returned.
1760 */
1761 static noinline_for_stack
1762 int replace_path(struct btrfs_trans_handle *trans,
1763 struct btrfs_root *dest, struct btrfs_root *src,
1764 struct btrfs_path *path, struct btrfs_key *next_key,
1765 int lowest_level, int max_level)
1766 {
1767 struct extent_buffer *eb;
1768 struct extent_buffer *parent;
1769 struct btrfs_key key;
1770 u64 old_bytenr;
1771 u64 new_bytenr;
1772 u64 old_ptr_gen;
1773 u64 new_ptr_gen;
1774 u64 last_snapshot;
1775 u32 blocksize;
1776 int cow = 0;
1777 int level;
1778 int ret;
1779 int slot;
1780
1781 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1782 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1783
1784 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1785 again:
1786 slot = path->slots[lowest_level];
1787 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1788
1789 eb = btrfs_lock_root_node(dest);
1790 btrfs_set_lock_blocking(eb);
1791 level = btrfs_header_level(eb);
1792
1793 if (level < lowest_level) {
1794 btrfs_tree_unlock(eb);
1795 free_extent_buffer(eb);
1796 return 0;
1797 }
1798
1799 if (cow) {
1800 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1801 BUG_ON(ret);
1802 }
1803 btrfs_set_lock_blocking(eb);
1804
1805 if (next_key) {
1806 next_key->objectid = (u64)-1;
1807 next_key->type = (u8)-1;
1808 next_key->offset = (u64)-1;
1809 }
1810
1811 parent = eb;
1812 while (1) {
1813 level = btrfs_header_level(parent);
1814 BUG_ON(level < lowest_level);
1815
1816 ret = btrfs_bin_search(parent, &key, level, &slot);
1817 if (ret && slot > 0)
1818 slot--;
1819
1820 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1821 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1822
1823 old_bytenr = btrfs_node_blockptr(parent, slot);
1824 blocksize = dest->nodesize;
1825 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1826
1827 if (level <= max_level) {
1828 eb = path->nodes[level];
1829 new_bytenr = btrfs_node_blockptr(eb,
1830 path->slots[level]);
1831 new_ptr_gen = btrfs_node_ptr_generation(eb,
1832 path->slots[level]);
1833 } else {
1834 new_bytenr = 0;
1835 new_ptr_gen = 0;
1836 }
1837
1838 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1839 ret = level;
1840 break;
1841 }
1842
1843 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1844 memcmp_node_keys(parent, slot, path, level)) {
1845 if (level <= lowest_level) {
1846 ret = 0;
1847 break;
1848 }
1849
1850 eb = read_tree_block(dest, old_bytenr, old_ptr_gen);
1851 if (IS_ERR(eb)) {
1852 ret = PTR_ERR(eb);
1853 } else if (!extent_buffer_uptodate(eb)) {
1854 ret = -EIO;
1855 free_extent_buffer(eb);
1856 break;
1857 }
1858 btrfs_tree_lock(eb);
1859 if (cow) {
1860 ret = btrfs_cow_block(trans, dest, eb, parent,
1861 slot, &eb);
1862 BUG_ON(ret);
1863 }
1864 btrfs_set_lock_blocking(eb);
1865
1866 btrfs_tree_unlock(parent);
1867 free_extent_buffer(parent);
1868
1869 parent = eb;
1870 continue;
1871 }
1872
1873 if (!cow) {
1874 btrfs_tree_unlock(parent);
1875 free_extent_buffer(parent);
1876 cow = 1;
1877 goto again;
1878 }
1879
1880 btrfs_node_key_to_cpu(path->nodes[level], &key,
1881 path->slots[level]);
1882 btrfs_release_path(path);
1883
1884 path->lowest_level = level;
1885 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1886 path->lowest_level = 0;
1887 BUG_ON(ret);
1888
1889 /*
1890 * swap blocks in fs tree and reloc tree.
1891 */
1892 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1893 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1894 btrfs_mark_buffer_dirty(parent);
1895
1896 btrfs_set_node_blockptr(path->nodes[level],
1897 path->slots[level], old_bytenr);
1898 btrfs_set_node_ptr_generation(path->nodes[level],
1899 path->slots[level], old_ptr_gen);
1900 btrfs_mark_buffer_dirty(path->nodes[level]);
1901
1902 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1903 path->nodes[level]->start,
1904 src->root_key.objectid, level - 1, 0);
1905 BUG_ON(ret);
1906 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1907 0, dest->root_key.objectid, level - 1,
1908 0);
1909 BUG_ON(ret);
1910
1911 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1912 path->nodes[level]->start,
1913 src->root_key.objectid, level - 1, 0);
1914 BUG_ON(ret);
1915
1916 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1917 0, dest->root_key.objectid, level - 1,
1918 0);
1919 BUG_ON(ret);
1920
1921 btrfs_unlock_up_safe(path, 0);
1922
1923 ret = level;
1924 break;
1925 }
1926 btrfs_tree_unlock(parent);
1927 free_extent_buffer(parent);
1928 return ret;
1929 }
1930
1931 /*
1932 * helper to find next relocated block in reloc tree
1933 */
1934 static noinline_for_stack
1935 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1936 int *level)
1937 {
1938 struct extent_buffer *eb;
1939 int i;
1940 u64 last_snapshot;
1941 u32 nritems;
1942
1943 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1944
1945 for (i = 0; i < *level; i++) {
1946 free_extent_buffer(path->nodes[i]);
1947 path->nodes[i] = NULL;
1948 }
1949
1950 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1951 eb = path->nodes[i];
1952 nritems = btrfs_header_nritems(eb);
1953 while (path->slots[i] + 1 < nritems) {
1954 path->slots[i]++;
1955 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1956 last_snapshot)
1957 continue;
1958
1959 *level = i;
1960 return 0;
1961 }
1962 free_extent_buffer(path->nodes[i]);
1963 path->nodes[i] = NULL;
1964 }
1965 return 1;
1966 }
1967
1968 /*
1969 * walk down reloc tree to find relocated block of lowest level
1970 */
1971 static noinline_for_stack
1972 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1973 int *level)
1974 {
1975 struct extent_buffer *eb = NULL;
1976 int i;
1977 u64 bytenr;
1978 u64 ptr_gen = 0;
1979 u64 last_snapshot;
1980 u32 nritems;
1981
1982 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1983
1984 for (i = *level; i > 0; i--) {
1985 eb = path->nodes[i];
1986 nritems = btrfs_header_nritems(eb);
1987 while (path->slots[i] < nritems) {
1988 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1989 if (ptr_gen > last_snapshot)
1990 break;
1991 path->slots[i]++;
1992 }
1993 if (path->slots[i] >= nritems) {
1994 if (i == *level)
1995 break;
1996 *level = i + 1;
1997 return 0;
1998 }
1999 if (i == 1) {
2000 *level = i;
2001 return 0;
2002 }
2003
2004 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2005 eb = read_tree_block(root, bytenr, ptr_gen);
2006 if (IS_ERR(eb)) {
2007 return PTR_ERR(eb);
2008 } else if (!extent_buffer_uptodate(eb)) {
2009 free_extent_buffer(eb);
2010 return -EIO;
2011 }
2012 BUG_ON(btrfs_header_level(eb) != i - 1);
2013 path->nodes[i - 1] = eb;
2014 path->slots[i - 1] = 0;
2015 }
2016 return 1;
2017 }
2018
2019 /*
2020 * invalidate extent cache for file extents whose key in range of
2021 * [min_key, max_key)
2022 */
2023 static int invalidate_extent_cache(struct btrfs_root *root,
2024 struct btrfs_key *min_key,
2025 struct btrfs_key *max_key)
2026 {
2027 struct inode *inode = NULL;
2028 u64 objectid;
2029 u64 start, end;
2030 u64 ino;
2031
2032 objectid = min_key->objectid;
2033 while (1) {
2034 cond_resched();
2035 iput(inode);
2036
2037 if (objectid > max_key->objectid)
2038 break;
2039
2040 inode = find_next_inode(root, objectid);
2041 if (!inode)
2042 break;
2043 ino = btrfs_ino(inode);
2044
2045 if (ino > max_key->objectid) {
2046 iput(inode);
2047 break;
2048 }
2049
2050 objectid = ino + 1;
2051 if (!S_ISREG(inode->i_mode))
2052 continue;
2053
2054 if (unlikely(min_key->objectid == ino)) {
2055 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2056 continue;
2057 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2058 start = 0;
2059 else {
2060 start = min_key->offset;
2061 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
2062 }
2063 } else {
2064 start = 0;
2065 }
2066
2067 if (unlikely(max_key->objectid == ino)) {
2068 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2069 continue;
2070 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2071 end = (u64)-1;
2072 } else {
2073 if (max_key->offset == 0)
2074 continue;
2075 end = max_key->offset;
2076 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
2077 end--;
2078 }
2079 } else {
2080 end = (u64)-1;
2081 }
2082
2083 /* the lock_extent waits for readpage to complete */
2084 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2085 btrfs_drop_extent_cache(inode, start, end, 1);
2086 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2087 }
2088 return 0;
2089 }
2090
2091 static int find_next_key(struct btrfs_path *path, int level,
2092 struct btrfs_key *key)
2093
2094 {
2095 while (level < BTRFS_MAX_LEVEL) {
2096 if (!path->nodes[level])
2097 break;
2098 if (path->slots[level] + 1 <
2099 btrfs_header_nritems(path->nodes[level])) {
2100 btrfs_node_key_to_cpu(path->nodes[level], key,
2101 path->slots[level] + 1);
2102 return 0;
2103 }
2104 level++;
2105 }
2106 return 1;
2107 }
2108
2109 /*
2110 * merge the relocated tree blocks in reloc tree with corresponding
2111 * fs tree.
2112 */
2113 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2114 struct btrfs_root *root)
2115 {
2116 LIST_HEAD(inode_list);
2117 struct btrfs_key key;
2118 struct btrfs_key next_key;
2119 struct btrfs_trans_handle *trans = NULL;
2120 struct btrfs_root *reloc_root;
2121 struct btrfs_root_item *root_item;
2122 struct btrfs_path *path;
2123 struct extent_buffer *leaf;
2124 int level;
2125 int max_level;
2126 int replaced = 0;
2127 int ret;
2128 int err = 0;
2129 u32 min_reserved;
2130
2131 path = btrfs_alloc_path();
2132 if (!path)
2133 return -ENOMEM;
2134 path->reada = READA_FORWARD;
2135
2136 reloc_root = root->reloc_root;
2137 root_item = &reloc_root->root_item;
2138
2139 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2140 level = btrfs_root_level(root_item);
2141 extent_buffer_get(reloc_root->node);
2142 path->nodes[level] = reloc_root->node;
2143 path->slots[level] = 0;
2144 } else {
2145 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2146
2147 level = root_item->drop_level;
2148 BUG_ON(level == 0);
2149 path->lowest_level = level;
2150 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2151 path->lowest_level = 0;
2152 if (ret < 0) {
2153 btrfs_free_path(path);
2154 return ret;
2155 }
2156
2157 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2158 path->slots[level]);
2159 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2160
2161 btrfs_unlock_up_safe(path, 0);
2162 }
2163
2164 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2165 memset(&next_key, 0, sizeof(next_key));
2166
2167 while (1) {
2168 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2169 BTRFS_RESERVE_FLUSH_ALL);
2170 if (ret) {
2171 err = ret;
2172 goto out;
2173 }
2174 trans = btrfs_start_transaction(root, 0);
2175 if (IS_ERR(trans)) {
2176 err = PTR_ERR(trans);
2177 trans = NULL;
2178 goto out;
2179 }
2180 trans->block_rsv = rc->block_rsv;
2181
2182 replaced = 0;
2183 max_level = level;
2184
2185 ret = walk_down_reloc_tree(reloc_root, path, &level);
2186 if (ret < 0) {
2187 err = ret;
2188 goto out;
2189 }
2190 if (ret > 0)
2191 break;
2192
2193 if (!find_next_key(path, level, &key) &&
2194 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2195 ret = 0;
2196 } else {
2197 ret = replace_path(trans, root, reloc_root, path,
2198 &next_key, level, max_level);
2199 }
2200 if (ret < 0) {
2201 err = ret;
2202 goto out;
2203 }
2204
2205 if (ret > 0) {
2206 level = ret;
2207 btrfs_node_key_to_cpu(path->nodes[level], &key,
2208 path->slots[level]);
2209 replaced = 1;
2210 }
2211
2212 ret = walk_up_reloc_tree(reloc_root, path, &level);
2213 if (ret > 0)
2214 break;
2215
2216 BUG_ON(level == 0);
2217 /*
2218 * save the merging progress in the drop_progress.
2219 * this is OK since root refs == 1 in this case.
2220 */
2221 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2222 path->slots[level]);
2223 root_item->drop_level = level;
2224
2225 btrfs_end_transaction_throttle(trans, root);
2226 trans = NULL;
2227
2228 btrfs_btree_balance_dirty(root);
2229
2230 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2231 invalidate_extent_cache(root, &key, &next_key);
2232 }
2233
2234 /*
2235 * handle the case only one block in the fs tree need to be
2236 * relocated and the block is tree root.
2237 */
2238 leaf = btrfs_lock_root_node(root);
2239 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2240 btrfs_tree_unlock(leaf);
2241 free_extent_buffer(leaf);
2242 if (ret < 0)
2243 err = ret;
2244 out:
2245 btrfs_free_path(path);
2246
2247 if (err == 0) {
2248 memset(&root_item->drop_progress, 0,
2249 sizeof(root_item->drop_progress));
2250 root_item->drop_level = 0;
2251 btrfs_set_root_refs(root_item, 0);
2252 btrfs_update_reloc_root(trans, root);
2253 }
2254
2255 if (trans)
2256 btrfs_end_transaction_throttle(trans, root);
2257
2258 btrfs_btree_balance_dirty(root);
2259
2260 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2261 invalidate_extent_cache(root, &key, &next_key);
2262
2263 return err;
2264 }
2265
2266 static noinline_for_stack
2267 int prepare_to_merge(struct reloc_control *rc, int err)
2268 {
2269 struct btrfs_root *root = rc->extent_root;
2270 struct btrfs_root *reloc_root;
2271 struct btrfs_trans_handle *trans;
2272 LIST_HEAD(reloc_roots);
2273 u64 num_bytes = 0;
2274 int ret;
2275
2276 mutex_lock(&root->fs_info->reloc_mutex);
2277 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2278 rc->merging_rsv_size += rc->nodes_relocated * 2;
2279 mutex_unlock(&root->fs_info->reloc_mutex);
2280
2281 again:
2282 if (!err) {
2283 num_bytes = rc->merging_rsv_size;
2284 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2285 BTRFS_RESERVE_FLUSH_ALL);
2286 if (ret)
2287 err = ret;
2288 }
2289
2290 trans = btrfs_join_transaction(rc->extent_root);
2291 if (IS_ERR(trans)) {
2292 if (!err)
2293 btrfs_block_rsv_release(rc->extent_root,
2294 rc->block_rsv, num_bytes);
2295 return PTR_ERR(trans);
2296 }
2297
2298 if (!err) {
2299 if (num_bytes != rc->merging_rsv_size) {
2300 btrfs_end_transaction(trans, rc->extent_root);
2301 btrfs_block_rsv_release(rc->extent_root,
2302 rc->block_rsv, num_bytes);
2303 goto again;
2304 }
2305 }
2306
2307 rc->merge_reloc_tree = 1;
2308
2309 while (!list_empty(&rc->reloc_roots)) {
2310 reloc_root = list_entry(rc->reloc_roots.next,
2311 struct btrfs_root, root_list);
2312 list_del_init(&reloc_root->root_list);
2313
2314 root = read_fs_root(reloc_root->fs_info,
2315 reloc_root->root_key.offset);
2316 BUG_ON(IS_ERR(root));
2317 BUG_ON(root->reloc_root != reloc_root);
2318
2319 /*
2320 * set reference count to 1, so btrfs_recover_relocation
2321 * knows it should resumes merging
2322 */
2323 if (!err)
2324 btrfs_set_root_refs(&reloc_root->root_item, 1);
2325 btrfs_update_reloc_root(trans, root);
2326
2327 list_add(&reloc_root->root_list, &reloc_roots);
2328 }
2329
2330 list_splice(&reloc_roots, &rc->reloc_roots);
2331
2332 if (!err)
2333 btrfs_commit_transaction(trans, rc->extent_root);
2334 else
2335 btrfs_end_transaction(trans, rc->extent_root);
2336 return err;
2337 }
2338
2339 static noinline_for_stack
2340 void free_reloc_roots(struct list_head *list)
2341 {
2342 struct btrfs_root *reloc_root;
2343
2344 while (!list_empty(list)) {
2345 reloc_root = list_entry(list->next, struct btrfs_root,
2346 root_list);
2347 __del_reloc_root(reloc_root);
2348 }
2349 }
2350
2351 static noinline_for_stack
2352 void merge_reloc_roots(struct reloc_control *rc)
2353 {
2354 struct btrfs_root *root;
2355 struct btrfs_root *reloc_root;
2356 u64 last_snap;
2357 u64 otransid;
2358 u64 objectid;
2359 LIST_HEAD(reloc_roots);
2360 int found = 0;
2361 int ret = 0;
2362 again:
2363 root = rc->extent_root;
2364
2365 /*
2366 * this serializes us with btrfs_record_root_in_transaction,
2367 * we have to make sure nobody is in the middle of
2368 * adding their roots to the list while we are
2369 * doing this splice
2370 */
2371 mutex_lock(&root->fs_info->reloc_mutex);
2372 list_splice_init(&rc->reloc_roots, &reloc_roots);
2373 mutex_unlock(&root->fs_info->reloc_mutex);
2374
2375 while (!list_empty(&reloc_roots)) {
2376 found = 1;
2377 reloc_root = list_entry(reloc_roots.next,
2378 struct btrfs_root, root_list);
2379
2380 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2381 root = read_fs_root(reloc_root->fs_info,
2382 reloc_root->root_key.offset);
2383 BUG_ON(IS_ERR(root));
2384 BUG_ON(root->reloc_root != reloc_root);
2385
2386 ret = merge_reloc_root(rc, root);
2387 if (ret) {
2388 if (list_empty(&reloc_root->root_list))
2389 list_add_tail(&reloc_root->root_list,
2390 &reloc_roots);
2391 goto out;
2392 }
2393 } else {
2394 list_del_init(&reloc_root->root_list);
2395 }
2396
2397 /*
2398 * we keep the old last snapshod transid in rtranid when we
2399 * created the relocation tree.
2400 */
2401 last_snap = btrfs_root_rtransid(&reloc_root->root_item);
2402 otransid = btrfs_root_otransid(&reloc_root->root_item);
2403 objectid = reloc_root->root_key.offset;
2404
2405 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2406 if (ret < 0) {
2407 if (list_empty(&reloc_root->root_list))
2408 list_add_tail(&reloc_root->root_list,
2409 &reloc_roots);
2410 goto out;
2411 }
2412 }
2413
2414 if (found) {
2415 found = 0;
2416 goto again;
2417 }
2418 out:
2419 if (ret) {
2420 btrfs_std_error(root->fs_info, ret, NULL);
2421 if (!list_empty(&reloc_roots))
2422 free_reloc_roots(&reloc_roots);
2423
2424 /* new reloc root may be added */
2425 mutex_lock(&root->fs_info->reloc_mutex);
2426 list_splice_init(&rc->reloc_roots, &reloc_roots);
2427 mutex_unlock(&root->fs_info->reloc_mutex);
2428 if (!list_empty(&reloc_roots))
2429 free_reloc_roots(&reloc_roots);
2430 }
2431
2432 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2433 }
2434
2435 static void free_block_list(struct rb_root *blocks)
2436 {
2437 struct tree_block *block;
2438 struct rb_node *rb_node;
2439 while ((rb_node = rb_first(blocks))) {
2440 block = rb_entry(rb_node, struct tree_block, rb_node);
2441 rb_erase(rb_node, blocks);
2442 kfree(block);
2443 }
2444 }
2445
2446 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2447 struct btrfs_root *reloc_root)
2448 {
2449 struct btrfs_root *root;
2450
2451 if (reloc_root->last_trans == trans->transid)
2452 return 0;
2453
2454 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2455 BUG_ON(IS_ERR(root));
2456 BUG_ON(root->reloc_root != reloc_root);
2457
2458 return btrfs_record_root_in_trans(trans, root);
2459 }
2460
2461 static noinline_for_stack
2462 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2463 struct reloc_control *rc,
2464 struct backref_node *node,
2465 struct backref_edge *edges[])
2466 {
2467 struct backref_node *next;
2468 struct btrfs_root *root;
2469 int index = 0;
2470
2471 next = node;
2472 while (1) {
2473 cond_resched();
2474 next = walk_up_backref(next, edges, &index);
2475 root = next->root;
2476 BUG_ON(!root);
2477 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2478
2479 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2480 record_reloc_root_in_trans(trans, root);
2481 break;
2482 }
2483
2484 btrfs_record_root_in_trans(trans, root);
2485 root = root->reloc_root;
2486
2487 if (next->new_bytenr != root->node->start) {
2488 BUG_ON(next->new_bytenr);
2489 BUG_ON(!list_empty(&next->list));
2490 next->new_bytenr = root->node->start;
2491 next->root = root;
2492 list_add_tail(&next->list,
2493 &rc->backref_cache.changed);
2494 __mark_block_processed(rc, next);
2495 break;
2496 }
2497
2498 WARN_ON(1);
2499 root = NULL;
2500 next = walk_down_backref(edges, &index);
2501 if (!next || next->level <= node->level)
2502 break;
2503 }
2504 if (!root)
2505 return NULL;
2506
2507 next = node;
2508 /* setup backref node path for btrfs_reloc_cow_block */
2509 while (1) {
2510 rc->backref_cache.path[next->level] = next;
2511 if (--index < 0)
2512 break;
2513 next = edges[index]->node[UPPER];
2514 }
2515 return root;
2516 }
2517
2518 /*
2519 * select a tree root for relocation. return NULL if the block
2520 * is reference counted. we should use do_relocation() in this
2521 * case. return a tree root pointer if the block isn't reference
2522 * counted. return -ENOENT if the block is root of reloc tree.
2523 */
2524 static noinline_for_stack
2525 struct btrfs_root *select_one_root(struct backref_node *node)
2526 {
2527 struct backref_node *next;
2528 struct btrfs_root *root;
2529 struct btrfs_root *fs_root = NULL;
2530 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2531 int index = 0;
2532
2533 next = node;
2534 while (1) {
2535 cond_resched();
2536 next = walk_up_backref(next, edges, &index);
2537 root = next->root;
2538 BUG_ON(!root);
2539
2540 /* no other choice for non-references counted tree */
2541 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2542 return root;
2543
2544 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2545 fs_root = root;
2546
2547 if (next != node)
2548 return NULL;
2549
2550 next = walk_down_backref(edges, &index);
2551 if (!next || next->level <= node->level)
2552 break;
2553 }
2554
2555 if (!fs_root)
2556 return ERR_PTR(-ENOENT);
2557 return fs_root;
2558 }
2559
2560 static noinline_for_stack
2561 u64 calcu_metadata_size(struct reloc_control *rc,
2562 struct backref_node *node, int reserve)
2563 {
2564 struct backref_node *next = node;
2565 struct backref_edge *edge;
2566 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2567 u64 num_bytes = 0;
2568 int index = 0;
2569
2570 BUG_ON(reserve && node->processed);
2571
2572 while (next) {
2573 cond_resched();
2574 while (1) {
2575 if (next->processed && (reserve || next != node))
2576 break;
2577
2578 num_bytes += rc->extent_root->nodesize;
2579
2580 if (list_empty(&next->upper))
2581 break;
2582
2583 edge = list_entry(next->upper.next,
2584 struct backref_edge, list[LOWER]);
2585 edges[index++] = edge;
2586 next = edge->node[UPPER];
2587 }
2588 next = walk_down_backref(edges, &index);
2589 }
2590 return num_bytes;
2591 }
2592
2593 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2594 struct reloc_control *rc,
2595 struct backref_node *node)
2596 {
2597 struct btrfs_root *root = rc->extent_root;
2598 u64 num_bytes;
2599 int ret;
2600 u64 tmp;
2601
2602 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2603
2604 trans->block_rsv = rc->block_rsv;
2605 rc->reserved_bytes += num_bytes;
2606 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2607 BTRFS_RESERVE_FLUSH_ALL);
2608 if (ret) {
2609 if (ret == -EAGAIN) {
2610 tmp = rc->extent_root->nodesize *
2611 RELOCATION_RESERVED_NODES;
2612 while (tmp <= rc->reserved_bytes)
2613 tmp <<= 1;
2614 /*
2615 * only one thread can access block_rsv at this point,
2616 * so we don't need hold lock to protect block_rsv.
2617 * we expand more reservation size here to allow enough
2618 * space for relocation and we will return eailer in
2619 * enospc case.
2620 */
2621 rc->block_rsv->size = tmp + rc->extent_root->nodesize *
2622 RELOCATION_RESERVED_NODES;
2623 }
2624 return ret;
2625 }
2626
2627 return 0;
2628 }
2629
2630 /*
2631 * relocate a block tree, and then update pointers in upper level
2632 * blocks that reference the block to point to the new location.
2633 *
2634 * if called by link_to_upper, the block has already been relocated.
2635 * in that case this function just updates pointers.
2636 */
2637 static int do_relocation(struct btrfs_trans_handle *trans,
2638 struct reloc_control *rc,
2639 struct backref_node *node,
2640 struct btrfs_key *key,
2641 struct btrfs_path *path, int lowest)
2642 {
2643 struct backref_node *upper;
2644 struct backref_edge *edge;
2645 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2646 struct btrfs_root *root;
2647 struct extent_buffer *eb;
2648 u32 blocksize;
2649 u64 bytenr;
2650 u64 generation;
2651 int slot;
2652 int ret;
2653 int err = 0;
2654
2655 BUG_ON(lowest && node->eb);
2656
2657 path->lowest_level = node->level + 1;
2658 rc->backref_cache.path[node->level] = node;
2659 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2660 cond_resched();
2661
2662 upper = edge->node[UPPER];
2663 root = select_reloc_root(trans, rc, upper, edges);
2664 BUG_ON(!root);
2665
2666 if (upper->eb && !upper->locked) {
2667 if (!lowest) {
2668 ret = btrfs_bin_search(upper->eb, key,
2669 upper->level, &slot);
2670 BUG_ON(ret);
2671 bytenr = btrfs_node_blockptr(upper->eb, slot);
2672 if (node->eb->start == bytenr)
2673 goto next;
2674 }
2675 drop_node_buffer(upper);
2676 }
2677
2678 if (!upper->eb) {
2679 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2680 if (ret < 0) {
2681 err = ret;
2682 break;
2683 }
2684 BUG_ON(ret > 0);
2685
2686 if (!upper->eb) {
2687 upper->eb = path->nodes[upper->level];
2688 path->nodes[upper->level] = NULL;
2689 } else {
2690 BUG_ON(upper->eb != path->nodes[upper->level]);
2691 }
2692
2693 upper->locked = 1;
2694 path->locks[upper->level] = 0;
2695
2696 slot = path->slots[upper->level];
2697 btrfs_release_path(path);
2698 } else {
2699 ret = btrfs_bin_search(upper->eb, key, upper->level,
2700 &slot);
2701 BUG_ON(ret);
2702 }
2703
2704 bytenr = btrfs_node_blockptr(upper->eb, slot);
2705 if (lowest) {
2706 BUG_ON(bytenr != node->bytenr);
2707 } else {
2708 if (node->eb->start == bytenr)
2709 goto next;
2710 }
2711
2712 blocksize = root->nodesize;
2713 generation = btrfs_node_ptr_generation(upper->eb, slot);
2714 eb = read_tree_block(root, bytenr, generation);
2715 if (IS_ERR(eb)) {
2716 err = PTR_ERR(eb);
2717 goto next;
2718 } else if (!extent_buffer_uptodate(eb)) {
2719 free_extent_buffer(eb);
2720 err = -EIO;
2721 goto next;
2722 }
2723 btrfs_tree_lock(eb);
2724 btrfs_set_lock_blocking(eb);
2725
2726 if (!node->eb) {
2727 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2728 slot, &eb);
2729 btrfs_tree_unlock(eb);
2730 free_extent_buffer(eb);
2731 if (ret < 0) {
2732 err = ret;
2733 goto next;
2734 }
2735 BUG_ON(node->eb != eb);
2736 } else {
2737 btrfs_set_node_blockptr(upper->eb, slot,
2738 node->eb->start);
2739 btrfs_set_node_ptr_generation(upper->eb, slot,
2740 trans->transid);
2741 btrfs_mark_buffer_dirty(upper->eb);
2742
2743 ret = btrfs_inc_extent_ref(trans, root,
2744 node->eb->start, blocksize,
2745 upper->eb->start,
2746 btrfs_header_owner(upper->eb),
2747 node->level, 0);
2748 BUG_ON(ret);
2749
2750 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2751 BUG_ON(ret);
2752 }
2753 next:
2754 if (!upper->pending)
2755 drop_node_buffer(upper);
2756 else
2757 unlock_node_buffer(upper);
2758 if (err)
2759 break;
2760 }
2761
2762 if (!err && node->pending) {
2763 drop_node_buffer(node);
2764 list_move_tail(&node->list, &rc->backref_cache.changed);
2765 node->pending = 0;
2766 }
2767
2768 path->lowest_level = 0;
2769 BUG_ON(err == -ENOSPC);
2770 return err;
2771 }
2772
2773 static int link_to_upper(struct btrfs_trans_handle *trans,
2774 struct reloc_control *rc,
2775 struct backref_node *node,
2776 struct btrfs_path *path)
2777 {
2778 struct btrfs_key key;
2779
2780 btrfs_node_key_to_cpu(node->eb, &key, 0);
2781 return do_relocation(trans, rc, node, &key, path, 0);
2782 }
2783
2784 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2785 struct reloc_control *rc,
2786 struct btrfs_path *path, int err)
2787 {
2788 LIST_HEAD(list);
2789 struct backref_cache *cache = &rc->backref_cache;
2790 struct backref_node *node;
2791 int level;
2792 int ret;
2793
2794 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2795 while (!list_empty(&cache->pending[level])) {
2796 node = list_entry(cache->pending[level].next,
2797 struct backref_node, list);
2798 list_move_tail(&node->list, &list);
2799 BUG_ON(!node->pending);
2800
2801 if (!err) {
2802 ret = link_to_upper(trans, rc, node, path);
2803 if (ret < 0)
2804 err = ret;
2805 }
2806 }
2807 list_splice_init(&list, &cache->pending[level]);
2808 }
2809 return err;
2810 }
2811
2812 static void mark_block_processed(struct reloc_control *rc,
2813 u64 bytenr, u32 blocksize)
2814 {
2815 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2816 EXTENT_DIRTY, GFP_NOFS);
2817 }
2818
2819 static void __mark_block_processed(struct reloc_control *rc,
2820 struct backref_node *node)
2821 {
2822 u32 blocksize;
2823 if (node->level == 0 ||
2824 in_block_group(node->bytenr, rc->block_group)) {
2825 blocksize = rc->extent_root->nodesize;
2826 mark_block_processed(rc, node->bytenr, blocksize);
2827 }
2828 node->processed = 1;
2829 }
2830
2831 /*
2832 * mark a block and all blocks directly/indirectly reference the block
2833 * as processed.
2834 */
2835 static void update_processed_blocks(struct reloc_control *rc,
2836 struct backref_node *node)
2837 {
2838 struct backref_node *next = node;
2839 struct backref_edge *edge;
2840 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2841 int index = 0;
2842
2843 while (next) {
2844 cond_resched();
2845 while (1) {
2846 if (next->processed)
2847 break;
2848
2849 __mark_block_processed(rc, next);
2850
2851 if (list_empty(&next->upper))
2852 break;
2853
2854 edge = list_entry(next->upper.next,
2855 struct backref_edge, list[LOWER]);
2856 edges[index++] = edge;
2857 next = edge->node[UPPER];
2858 }
2859 next = walk_down_backref(edges, &index);
2860 }
2861 }
2862
2863 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2864 {
2865 u32 blocksize = rc->extent_root->nodesize;
2866
2867 if (test_range_bit(&rc->processed_blocks, bytenr,
2868 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2869 return 1;
2870 return 0;
2871 }
2872
2873 static int get_tree_block_key(struct reloc_control *rc,
2874 struct tree_block *block)
2875 {
2876 struct extent_buffer *eb;
2877
2878 BUG_ON(block->key_ready);
2879 eb = read_tree_block(rc->extent_root, block->bytenr,
2880 block->key.offset);
2881 if (IS_ERR(eb)) {
2882 return PTR_ERR(eb);
2883 } else if (!extent_buffer_uptodate(eb)) {
2884 free_extent_buffer(eb);
2885 return -EIO;
2886 }
2887 WARN_ON(btrfs_header_level(eb) != block->level);
2888 if (block->level == 0)
2889 btrfs_item_key_to_cpu(eb, &block->key, 0);
2890 else
2891 btrfs_node_key_to_cpu(eb, &block->key, 0);
2892 free_extent_buffer(eb);
2893 block->key_ready = 1;
2894 return 0;
2895 }
2896
2897 /*
2898 * helper function to relocate a tree block
2899 */
2900 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2901 struct reloc_control *rc,
2902 struct backref_node *node,
2903 struct btrfs_key *key,
2904 struct btrfs_path *path)
2905 {
2906 struct btrfs_root *root;
2907 int ret = 0;
2908
2909 if (!node)
2910 return 0;
2911
2912 BUG_ON(node->processed);
2913 root = select_one_root(node);
2914 if (root == ERR_PTR(-ENOENT)) {
2915 update_processed_blocks(rc, node);
2916 goto out;
2917 }
2918
2919 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2920 ret = reserve_metadata_space(trans, rc, node);
2921 if (ret)
2922 goto out;
2923 }
2924
2925 if (root) {
2926 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2927 BUG_ON(node->new_bytenr);
2928 BUG_ON(!list_empty(&node->list));
2929 btrfs_record_root_in_trans(trans, root);
2930 root = root->reloc_root;
2931 node->new_bytenr = root->node->start;
2932 node->root = root;
2933 list_add_tail(&node->list, &rc->backref_cache.changed);
2934 } else {
2935 path->lowest_level = node->level;
2936 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2937 btrfs_release_path(path);
2938 if (ret > 0)
2939 ret = 0;
2940 }
2941 if (!ret)
2942 update_processed_blocks(rc, node);
2943 } else {
2944 ret = do_relocation(trans, rc, node, key, path, 1);
2945 }
2946 out:
2947 if (ret || node->level == 0 || node->cowonly)
2948 remove_backref_node(&rc->backref_cache, node);
2949 return ret;
2950 }
2951
2952 /*
2953 * relocate a list of blocks
2954 */
2955 static noinline_for_stack
2956 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2957 struct reloc_control *rc, struct rb_root *blocks)
2958 {
2959 struct backref_node *node;
2960 struct btrfs_path *path;
2961 struct tree_block *block;
2962 struct rb_node *rb_node;
2963 int ret;
2964 int err = 0;
2965
2966 path = btrfs_alloc_path();
2967 if (!path) {
2968 err = -ENOMEM;
2969 goto out_free_blocks;
2970 }
2971
2972 rb_node = rb_first(blocks);
2973 while (rb_node) {
2974 block = rb_entry(rb_node, struct tree_block, rb_node);
2975 if (!block->key_ready)
2976 readahead_tree_block(rc->extent_root, block->bytenr);
2977 rb_node = rb_next(rb_node);
2978 }
2979
2980 rb_node = rb_first(blocks);
2981 while (rb_node) {
2982 block = rb_entry(rb_node, struct tree_block, rb_node);
2983 if (!block->key_ready) {
2984 err = get_tree_block_key(rc, block);
2985 if (err)
2986 goto out_free_path;
2987 }
2988 rb_node = rb_next(rb_node);
2989 }
2990
2991 rb_node = rb_first(blocks);
2992 while (rb_node) {
2993 block = rb_entry(rb_node, struct tree_block, rb_node);
2994
2995 node = build_backref_tree(rc, &block->key,
2996 block->level, block->bytenr);
2997 if (IS_ERR(node)) {
2998 err = PTR_ERR(node);
2999 goto out;
3000 }
3001
3002 ret = relocate_tree_block(trans, rc, node, &block->key,
3003 path);
3004 if (ret < 0) {
3005 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3006 err = ret;
3007 goto out;
3008 }
3009 rb_node = rb_next(rb_node);
3010 }
3011 out:
3012 err = finish_pending_nodes(trans, rc, path, err);
3013
3014 out_free_path:
3015 btrfs_free_path(path);
3016 out_free_blocks:
3017 free_block_list(blocks);
3018 return err;
3019 }
3020
3021 static noinline_for_stack
3022 int prealloc_file_extent_cluster(struct inode *inode,
3023 struct file_extent_cluster *cluster)
3024 {
3025 u64 alloc_hint = 0;
3026 u64 start;
3027 u64 end;
3028 u64 offset = BTRFS_I(inode)->index_cnt;
3029 u64 num_bytes;
3030 int nr = 0;
3031 int ret = 0;
3032
3033 BUG_ON(cluster->start != cluster->boundary[0]);
3034 inode_lock(inode);
3035
3036 ret = btrfs_check_data_free_space(inode, cluster->start,
3037 cluster->end + 1 - cluster->start);
3038 if (ret)
3039 goto out;
3040
3041 while (nr < cluster->nr) {
3042 start = cluster->boundary[nr] - offset;
3043 if (nr + 1 < cluster->nr)
3044 end = cluster->boundary[nr + 1] - 1 - offset;
3045 else
3046 end = cluster->end - offset;
3047
3048 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3049 num_bytes = end + 1 - start;
3050 ret = btrfs_prealloc_file_range(inode, 0, start,
3051 num_bytes, num_bytes,
3052 end + 1, &alloc_hint);
3053 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3054 if (ret)
3055 break;
3056 nr++;
3057 }
3058 btrfs_free_reserved_data_space(inode, cluster->start,
3059 cluster->end + 1 - cluster->start);
3060 out:
3061 inode_unlock(inode);
3062 return ret;
3063 }
3064
3065 static noinline_for_stack
3066 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3067 u64 block_start)
3068 {
3069 struct btrfs_root *root = BTRFS_I(inode)->root;
3070 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3071 struct extent_map *em;
3072 int ret = 0;
3073
3074 em = alloc_extent_map();
3075 if (!em)
3076 return -ENOMEM;
3077
3078 em->start = start;
3079 em->len = end + 1 - start;
3080 em->block_len = em->len;
3081 em->block_start = block_start;
3082 em->bdev = root->fs_info->fs_devices->latest_bdev;
3083 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3084
3085 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3086 while (1) {
3087 write_lock(&em_tree->lock);
3088 ret = add_extent_mapping(em_tree, em, 0);
3089 write_unlock(&em_tree->lock);
3090 if (ret != -EEXIST) {
3091 free_extent_map(em);
3092 break;
3093 }
3094 btrfs_drop_extent_cache(inode, start, end, 0);
3095 }
3096 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3097 return ret;
3098 }
3099
3100 static int relocate_file_extent_cluster(struct inode *inode,
3101 struct file_extent_cluster *cluster)
3102 {
3103 u64 page_start;
3104 u64 page_end;
3105 u64 offset = BTRFS_I(inode)->index_cnt;
3106 unsigned long index;
3107 unsigned long last_index;
3108 struct page *page;
3109 struct file_ra_state *ra;
3110 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3111 int nr = 0;
3112 int ret = 0;
3113
3114 if (!cluster->nr)
3115 return 0;
3116
3117 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3118 if (!ra)
3119 return -ENOMEM;
3120
3121 ret = prealloc_file_extent_cluster(inode, cluster);
3122 if (ret)
3123 goto out;
3124
3125 file_ra_state_init(ra, inode->i_mapping);
3126
3127 ret = setup_extent_mapping(inode, cluster->start - offset,
3128 cluster->end - offset, cluster->start);
3129 if (ret)
3130 goto out;
3131
3132 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
3133 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
3134 while (index <= last_index) {
3135 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
3136 if (ret)
3137 goto out;
3138
3139 page = find_lock_page(inode->i_mapping, index);
3140 if (!page) {
3141 page_cache_sync_readahead(inode->i_mapping,
3142 ra, NULL, index,
3143 last_index + 1 - index);
3144 page = find_or_create_page(inode->i_mapping, index,
3145 mask);
3146 if (!page) {
3147 btrfs_delalloc_release_metadata(inode,
3148 PAGE_CACHE_SIZE);
3149 ret = -ENOMEM;
3150 goto out;
3151 }
3152 }
3153
3154 if (PageReadahead(page)) {
3155 page_cache_async_readahead(inode->i_mapping,
3156 ra, NULL, page, index,
3157 last_index + 1 - index);
3158 }
3159
3160 if (!PageUptodate(page)) {
3161 btrfs_readpage(NULL, page);
3162 lock_page(page);
3163 if (!PageUptodate(page)) {
3164 unlock_page(page);
3165 page_cache_release(page);
3166 btrfs_delalloc_release_metadata(inode,
3167 PAGE_CACHE_SIZE);
3168 ret = -EIO;
3169 goto out;
3170 }
3171 }
3172
3173 page_start = page_offset(page);
3174 page_end = page_start + PAGE_CACHE_SIZE - 1;
3175
3176 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3177
3178 set_page_extent_mapped(page);
3179
3180 if (nr < cluster->nr &&
3181 page_start + offset == cluster->boundary[nr]) {
3182 set_extent_bits(&BTRFS_I(inode)->io_tree,
3183 page_start, page_end,
3184 EXTENT_BOUNDARY, GFP_NOFS);
3185 nr++;
3186 }
3187
3188 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3189 set_page_dirty(page);
3190
3191 unlock_extent(&BTRFS_I(inode)->io_tree,
3192 page_start, page_end);
3193 unlock_page(page);
3194 page_cache_release(page);
3195
3196 index++;
3197 balance_dirty_pages_ratelimited(inode->i_mapping);
3198 btrfs_throttle(BTRFS_I(inode)->root);
3199 }
3200 WARN_ON(nr != cluster->nr);
3201 out:
3202 kfree(ra);
3203 return ret;
3204 }
3205
3206 static noinline_for_stack
3207 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3208 struct file_extent_cluster *cluster)
3209 {
3210 int ret;
3211
3212 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3213 ret = relocate_file_extent_cluster(inode, cluster);
3214 if (ret)
3215 return ret;
3216 cluster->nr = 0;
3217 }
3218
3219 if (!cluster->nr)
3220 cluster->start = extent_key->objectid;
3221 else
3222 BUG_ON(cluster->nr >= MAX_EXTENTS);
3223 cluster->end = extent_key->objectid + extent_key->offset - 1;
3224 cluster->boundary[cluster->nr] = extent_key->objectid;
3225 cluster->nr++;
3226
3227 if (cluster->nr >= MAX_EXTENTS) {
3228 ret = relocate_file_extent_cluster(inode, cluster);
3229 if (ret)
3230 return ret;
3231 cluster->nr = 0;
3232 }
3233 return 0;
3234 }
3235
3236 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3237 static int get_ref_objectid_v0(struct reloc_control *rc,
3238 struct btrfs_path *path,
3239 struct btrfs_key *extent_key,
3240 u64 *ref_objectid, int *path_change)
3241 {
3242 struct btrfs_key key;
3243 struct extent_buffer *leaf;
3244 struct btrfs_extent_ref_v0 *ref0;
3245 int ret;
3246 int slot;
3247
3248 leaf = path->nodes[0];
3249 slot = path->slots[0];
3250 while (1) {
3251 if (slot >= btrfs_header_nritems(leaf)) {
3252 ret = btrfs_next_leaf(rc->extent_root, path);
3253 if (ret < 0)
3254 return ret;
3255 BUG_ON(ret > 0);
3256 leaf = path->nodes[0];
3257 slot = path->slots[0];
3258 if (path_change)
3259 *path_change = 1;
3260 }
3261 btrfs_item_key_to_cpu(leaf, &key, slot);
3262 if (key.objectid != extent_key->objectid)
3263 return -ENOENT;
3264
3265 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3266 slot++;
3267 continue;
3268 }
3269 ref0 = btrfs_item_ptr(leaf, slot,
3270 struct btrfs_extent_ref_v0);
3271 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3272 break;
3273 }
3274 return 0;
3275 }
3276 #endif
3277
3278 /*
3279 * helper to add a tree block to the list.
3280 * the major work is getting the generation and level of the block
3281 */
3282 static int add_tree_block(struct reloc_control *rc,
3283 struct btrfs_key *extent_key,
3284 struct btrfs_path *path,
3285 struct rb_root *blocks)
3286 {
3287 struct extent_buffer *eb;
3288 struct btrfs_extent_item *ei;
3289 struct btrfs_tree_block_info *bi;
3290 struct tree_block *block;
3291 struct rb_node *rb_node;
3292 u32 item_size;
3293 int level = -1;
3294 u64 generation;
3295
3296 eb = path->nodes[0];
3297 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3298
3299 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3300 item_size >= sizeof(*ei) + sizeof(*bi)) {
3301 ei = btrfs_item_ptr(eb, path->slots[0],
3302 struct btrfs_extent_item);
3303 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3304 bi = (struct btrfs_tree_block_info *)(ei + 1);
3305 level = btrfs_tree_block_level(eb, bi);
3306 } else {
3307 level = (int)extent_key->offset;
3308 }
3309 generation = btrfs_extent_generation(eb, ei);
3310 } else {
3311 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3312 u64 ref_owner;
3313 int ret;
3314
3315 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3316 ret = get_ref_objectid_v0(rc, path, extent_key,
3317 &ref_owner, NULL);
3318 if (ret < 0)
3319 return ret;
3320 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3321 level = (int)ref_owner;
3322 /* FIXME: get real generation */
3323 generation = 0;
3324 #else
3325 BUG();
3326 #endif
3327 }
3328
3329 btrfs_release_path(path);
3330
3331 BUG_ON(level == -1);
3332
3333 block = kmalloc(sizeof(*block), GFP_NOFS);
3334 if (!block)
3335 return -ENOMEM;
3336
3337 block->bytenr = extent_key->objectid;
3338 block->key.objectid = rc->extent_root->nodesize;
3339 block->key.offset = generation;
3340 block->level = level;
3341 block->key_ready = 0;
3342
3343 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3344 if (rb_node)
3345 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3346
3347 return 0;
3348 }
3349
3350 /*
3351 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3352 */
3353 static int __add_tree_block(struct reloc_control *rc,
3354 u64 bytenr, u32 blocksize,
3355 struct rb_root *blocks)
3356 {
3357 struct btrfs_path *path;
3358 struct btrfs_key key;
3359 int ret;
3360 bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info,
3361 SKINNY_METADATA);
3362
3363 if (tree_block_processed(bytenr, rc))
3364 return 0;
3365
3366 if (tree_search(blocks, bytenr))
3367 return 0;
3368
3369 path = btrfs_alloc_path();
3370 if (!path)
3371 return -ENOMEM;
3372 again:
3373 key.objectid = bytenr;
3374 if (skinny) {
3375 key.type = BTRFS_METADATA_ITEM_KEY;
3376 key.offset = (u64)-1;
3377 } else {
3378 key.type = BTRFS_EXTENT_ITEM_KEY;
3379 key.offset = blocksize;
3380 }
3381
3382 path->search_commit_root = 1;
3383 path->skip_locking = 1;
3384 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3385 if (ret < 0)
3386 goto out;
3387
3388 if (ret > 0 && skinny) {
3389 if (path->slots[0]) {
3390 path->slots[0]--;
3391 btrfs_item_key_to_cpu(path->nodes[0], &key,
3392 path->slots[0]);
3393 if (key.objectid == bytenr &&
3394 (key.type == BTRFS_METADATA_ITEM_KEY ||
3395 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3396 key.offset == blocksize)))
3397 ret = 0;
3398 }
3399
3400 if (ret) {
3401 skinny = false;
3402 btrfs_release_path(path);
3403 goto again;
3404 }
3405 }
3406 BUG_ON(ret);
3407
3408 ret = add_tree_block(rc, &key, path, blocks);
3409 out:
3410 btrfs_free_path(path);
3411 return ret;
3412 }
3413
3414 /*
3415 * helper to check if the block use full backrefs for pointers in it
3416 */
3417 static int block_use_full_backref(struct reloc_control *rc,
3418 struct extent_buffer *eb)
3419 {
3420 u64 flags;
3421 int ret;
3422
3423 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3424 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3425 return 1;
3426
3427 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3428 eb->start, btrfs_header_level(eb), 1,
3429 NULL, &flags);
3430 BUG_ON(ret);
3431
3432 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3433 ret = 1;
3434 else
3435 ret = 0;
3436 return ret;
3437 }
3438
3439 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3440 struct btrfs_block_group_cache *block_group,
3441 struct inode *inode,
3442 u64 ino)
3443 {
3444 struct btrfs_key key;
3445 struct btrfs_root *root = fs_info->tree_root;
3446 struct btrfs_trans_handle *trans;
3447 int ret = 0;
3448
3449 if (inode)
3450 goto truncate;
3451
3452 key.objectid = ino;
3453 key.type = BTRFS_INODE_ITEM_KEY;
3454 key.offset = 0;
3455
3456 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3457 if (IS_ERR(inode) || is_bad_inode(inode)) {
3458 if (!IS_ERR(inode))
3459 iput(inode);
3460 return -ENOENT;
3461 }
3462
3463 truncate:
3464 ret = btrfs_check_trunc_cache_free_space(root,
3465 &fs_info->global_block_rsv);
3466 if (ret)
3467 goto out;
3468
3469 trans = btrfs_join_transaction(root);
3470 if (IS_ERR(trans)) {
3471 ret = PTR_ERR(trans);
3472 goto out;
3473 }
3474
3475 ret = btrfs_truncate_free_space_cache(root, trans, block_group, inode);
3476
3477 btrfs_end_transaction(trans, root);
3478 btrfs_btree_balance_dirty(root);
3479 out:
3480 iput(inode);
3481 return ret;
3482 }
3483
3484 /*
3485 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3486 * this function scans fs tree to find blocks reference the data extent
3487 */
3488 static int find_data_references(struct reloc_control *rc,
3489 struct btrfs_key *extent_key,
3490 struct extent_buffer *leaf,
3491 struct btrfs_extent_data_ref *ref,
3492 struct rb_root *blocks)
3493 {
3494 struct btrfs_path *path;
3495 struct tree_block *block;
3496 struct btrfs_root *root;
3497 struct btrfs_file_extent_item *fi;
3498 struct rb_node *rb_node;
3499 struct btrfs_key key;
3500 u64 ref_root;
3501 u64 ref_objectid;
3502 u64 ref_offset;
3503 u32 ref_count;
3504 u32 nritems;
3505 int err = 0;
3506 int added = 0;
3507 int counted;
3508 int ret;
3509
3510 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3511 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3512 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3513 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3514
3515 /*
3516 * This is an extent belonging to the free space cache, lets just delete
3517 * it and redo the search.
3518 */
3519 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3520 ret = delete_block_group_cache(rc->extent_root->fs_info,
3521 rc->block_group,
3522 NULL, ref_objectid);
3523 if (ret != -ENOENT)
3524 return ret;
3525 ret = 0;
3526 }
3527
3528 path = btrfs_alloc_path();
3529 if (!path)
3530 return -ENOMEM;
3531 path->reada = READA_FORWARD;
3532
3533 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3534 if (IS_ERR(root)) {
3535 err = PTR_ERR(root);
3536 goto out;
3537 }
3538
3539 key.objectid = ref_objectid;
3540 key.type = BTRFS_EXTENT_DATA_KEY;
3541 if (ref_offset > ((u64)-1 << 32))
3542 key.offset = 0;
3543 else
3544 key.offset = ref_offset;
3545
3546 path->search_commit_root = 1;
3547 path->skip_locking = 1;
3548 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3549 if (ret < 0) {
3550 err = ret;
3551 goto out;
3552 }
3553
3554 leaf = path->nodes[0];
3555 nritems = btrfs_header_nritems(leaf);
3556 /*
3557 * the references in tree blocks that use full backrefs
3558 * are not counted in
3559 */
3560 if (block_use_full_backref(rc, leaf))
3561 counted = 0;
3562 else
3563 counted = 1;
3564 rb_node = tree_search(blocks, leaf->start);
3565 if (rb_node) {
3566 if (counted)
3567 added = 1;
3568 else
3569 path->slots[0] = nritems;
3570 }
3571
3572 while (ref_count > 0) {
3573 while (path->slots[0] >= nritems) {
3574 ret = btrfs_next_leaf(root, path);
3575 if (ret < 0) {
3576 err = ret;
3577 goto out;
3578 }
3579 if (WARN_ON(ret > 0))
3580 goto out;
3581
3582 leaf = path->nodes[0];
3583 nritems = btrfs_header_nritems(leaf);
3584 added = 0;
3585
3586 if (block_use_full_backref(rc, leaf))
3587 counted = 0;
3588 else
3589 counted = 1;
3590 rb_node = tree_search(blocks, leaf->start);
3591 if (rb_node) {
3592 if (counted)
3593 added = 1;
3594 else
3595 path->slots[0] = nritems;
3596 }
3597 }
3598
3599 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3600 if (WARN_ON(key.objectid != ref_objectid ||
3601 key.type != BTRFS_EXTENT_DATA_KEY))
3602 break;
3603
3604 fi = btrfs_item_ptr(leaf, path->slots[0],
3605 struct btrfs_file_extent_item);
3606
3607 if (btrfs_file_extent_type(leaf, fi) ==
3608 BTRFS_FILE_EXTENT_INLINE)
3609 goto next;
3610
3611 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3612 extent_key->objectid)
3613 goto next;
3614
3615 key.offset -= btrfs_file_extent_offset(leaf, fi);
3616 if (key.offset != ref_offset)
3617 goto next;
3618
3619 if (counted)
3620 ref_count--;
3621 if (added)
3622 goto next;
3623
3624 if (!tree_block_processed(leaf->start, rc)) {
3625 block = kmalloc(sizeof(*block), GFP_NOFS);
3626 if (!block) {
3627 err = -ENOMEM;
3628 break;
3629 }
3630 block->bytenr = leaf->start;
3631 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3632 block->level = 0;
3633 block->key_ready = 1;
3634 rb_node = tree_insert(blocks, block->bytenr,
3635 &block->rb_node);
3636 if (rb_node)
3637 backref_tree_panic(rb_node, -EEXIST,
3638 block->bytenr);
3639 }
3640 if (counted)
3641 added = 1;
3642 else
3643 path->slots[0] = nritems;
3644 next:
3645 path->slots[0]++;
3646
3647 }
3648 out:
3649 btrfs_free_path(path);
3650 return err;
3651 }
3652
3653 /*
3654 * helper to find all tree blocks that reference a given data extent
3655 */
3656 static noinline_for_stack
3657 int add_data_references(struct reloc_control *rc,
3658 struct btrfs_key *extent_key,
3659 struct btrfs_path *path,
3660 struct rb_root *blocks)
3661 {
3662 struct btrfs_key key;
3663 struct extent_buffer *eb;
3664 struct btrfs_extent_data_ref *dref;
3665 struct btrfs_extent_inline_ref *iref;
3666 unsigned long ptr;
3667 unsigned long end;
3668 u32 blocksize = rc->extent_root->nodesize;
3669 int ret = 0;
3670 int err = 0;
3671
3672 eb = path->nodes[0];
3673 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3674 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3675 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3676 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3677 ptr = end;
3678 else
3679 #endif
3680 ptr += sizeof(struct btrfs_extent_item);
3681
3682 while (ptr < end) {
3683 iref = (struct btrfs_extent_inline_ref *)ptr;
3684 key.type = btrfs_extent_inline_ref_type(eb, iref);
3685 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3686 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3687 ret = __add_tree_block(rc, key.offset, blocksize,
3688 blocks);
3689 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3690 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3691 ret = find_data_references(rc, extent_key,
3692 eb, dref, blocks);
3693 } else {
3694 BUG();
3695 }
3696 if (ret) {
3697 err = ret;
3698 goto out;
3699 }
3700 ptr += btrfs_extent_inline_ref_size(key.type);
3701 }
3702 WARN_ON(ptr > end);
3703
3704 while (1) {
3705 cond_resched();
3706 eb = path->nodes[0];
3707 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3708 ret = btrfs_next_leaf(rc->extent_root, path);
3709 if (ret < 0) {
3710 err = ret;
3711 break;
3712 }
3713 if (ret > 0)
3714 break;
3715 eb = path->nodes[0];
3716 }
3717
3718 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3719 if (key.objectid != extent_key->objectid)
3720 break;
3721
3722 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3723 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3724 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3725 #else
3726 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3727 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3728 #endif
3729 ret = __add_tree_block(rc, key.offset, blocksize,
3730 blocks);
3731 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3732 dref = btrfs_item_ptr(eb, path->slots[0],
3733 struct btrfs_extent_data_ref);
3734 ret = find_data_references(rc, extent_key,
3735 eb, dref, blocks);
3736 } else {
3737 ret = 0;
3738 }
3739 if (ret) {
3740 err = ret;
3741 break;
3742 }
3743 path->slots[0]++;
3744 }
3745 out:
3746 btrfs_release_path(path);
3747 if (err)
3748 free_block_list(blocks);
3749 return err;
3750 }
3751
3752 /*
3753 * helper to find next unprocessed extent
3754 */
3755 static noinline_for_stack
3756 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3757 struct btrfs_key *extent_key)
3758 {
3759 struct btrfs_key key;
3760 struct extent_buffer *leaf;
3761 u64 start, end, last;
3762 int ret;
3763
3764 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3765 while (1) {
3766 cond_resched();
3767 if (rc->search_start >= last) {
3768 ret = 1;
3769 break;
3770 }
3771
3772 key.objectid = rc->search_start;
3773 key.type = BTRFS_EXTENT_ITEM_KEY;
3774 key.offset = 0;
3775
3776 path->search_commit_root = 1;
3777 path->skip_locking = 1;
3778 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3779 0, 0);
3780 if (ret < 0)
3781 break;
3782 next:
3783 leaf = path->nodes[0];
3784 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3785 ret = btrfs_next_leaf(rc->extent_root, path);
3786 if (ret != 0)
3787 break;
3788 leaf = path->nodes[0];
3789 }
3790
3791 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3792 if (key.objectid >= last) {
3793 ret = 1;
3794 break;
3795 }
3796
3797 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3798 key.type != BTRFS_METADATA_ITEM_KEY) {
3799 path->slots[0]++;
3800 goto next;
3801 }
3802
3803 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3804 key.objectid + key.offset <= rc->search_start) {
3805 path->slots[0]++;
3806 goto next;
3807 }
3808
3809 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3810 key.objectid + rc->extent_root->nodesize <=
3811 rc->search_start) {
3812 path->slots[0]++;
3813 goto next;
3814 }
3815
3816 ret = find_first_extent_bit(&rc->processed_blocks,
3817 key.objectid, &start, &end,
3818 EXTENT_DIRTY, NULL);
3819
3820 if (ret == 0 && start <= key.objectid) {
3821 btrfs_release_path(path);
3822 rc->search_start = end + 1;
3823 } else {
3824 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3825 rc->search_start = key.objectid + key.offset;
3826 else
3827 rc->search_start = key.objectid +
3828 rc->extent_root->nodesize;
3829 memcpy(extent_key, &key, sizeof(key));
3830 return 0;
3831 }
3832 }
3833 btrfs_release_path(path);
3834 return ret;
3835 }
3836
3837 static void set_reloc_control(struct reloc_control *rc)
3838 {
3839 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3840
3841 mutex_lock(&fs_info->reloc_mutex);
3842 fs_info->reloc_ctl = rc;
3843 mutex_unlock(&fs_info->reloc_mutex);
3844 }
3845
3846 static void unset_reloc_control(struct reloc_control *rc)
3847 {
3848 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3849
3850 mutex_lock(&fs_info->reloc_mutex);
3851 fs_info->reloc_ctl = NULL;
3852 mutex_unlock(&fs_info->reloc_mutex);
3853 }
3854
3855 static int check_extent_flags(u64 flags)
3856 {
3857 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3858 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3859 return 1;
3860 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3861 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3862 return 1;
3863 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3864 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3865 return 1;
3866 return 0;
3867 }
3868
3869 static noinline_for_stack
3870 int prepare_to_relocate(struct reloc_control *rc)
3871 {
3872 struct btrfs_trans_handle *trans;
3873
3874 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3875 BTRFS_BLOCK_RSV_TEMP);
3876 if (!rc->block_rsv)
3877 return -ENOMEM;
3878
3879 memset(&rc->cluster, 0, sizeof(rc->cluster));
3880 rc->search_start = rc->block_group->key.objectid;
3881 rc->extents_found = 0;
3882 rc->nodes_relocated = 0;
3883 rc->merging_rsv_size = 0;
3884 rc->reserved_bytes = 0;
3885 rc->block_rsv->size = rc->extent_root->nodesize *
3886 RELOCATION_RESERVED_NODES;
3887
3888 rc->create_reloc_tree = 1;
3889 set_reloc_control(rc);
3890
3891 trans = btrfs_join_transaction(rc->extent_root);
3892 if (IS_ERR(trans)) {
3893 unset_reloc_control(rc);
3894 /*
3895 * extent tree is not a ref_cow tree and has no reloc_root to
3896 * cleanup. And callers are responsible to free the above
3897 * block rsv.
3898 */
3899 return PTR_ERR(trans);
3900 }
3901 btrfs_commit_transaction(trans, rc->extent_root);
3902 return 0;
3903 }
3904
3905 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3906 {
3907 struct rb_root blocks = RB_ROOT;
3908 struct btrfs_key key;
3909 struct btrfs_trans_handle *trans = NULL;
3910 struct btrfs_path *path;
3911 struct btrfs_extent_item *ei;
3912 u64 flags;
3913 u32 item_size;
3914 int ret;
3915 int err = 0;
3916 int progress = 0;
3917
3918 path = btrfs_alloc_path();
3919 if (!path)
3920 return -ENOMEM;
3921 path->reada = READA_FORWARD;
3922
3923 ret = prepare_to_relocate(rc);
3924 if (ret) {
3925 err = ret;
3926 goto out_free;
3927 }
3928
3929 while (1) {
3930 rc->reserved_bytes = 0;
3931 ret = btrfs_block_rsv_refill(rc->extent_root,
3932 rc->block_rsv, rc->block_rsv->size,
3933 BTRFS_RESERVE_FLUSH_ALL);
3934 if (ret) {
3935 err = ret;
3936 break;
3937 }
3938 progress++;
3939 trans = btrfs_start_transaction(rc->extent_root, 0);
3940 if (IS_ERR(trans)) {
3941 err = PTR_ERR(trans);
3942 trans = NULL;
3943 break;
3944 }
3945 restart:
3946 if (update_backref_cache(trans, &rc->backref_cache)) {
3947 btrfs_end_transaction(trans, rc->extent_root);
3948 continue;
3949 }
3950
3951 ret = find_next_extent(rc, path, &key);
3952 if (ret < 0)
3953 err = ret;
3954 if (ret != 0)
3955 break;
3956
3957 rc->extents_found++;
3958
3959 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3960 struct btrfs_extent_item);
3961 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3962 if (item_size >= sizeof(*ei)) {
3963 flags = btrfs_extent_flags(path->nodes[0], ei);
3964 ret = check_extent_flags(flags);
3965 BUG_ON(ret);
3966
3967 } else {
3968 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3969 u64 ref_owner;
3970 int path_change = 0;
3971
3972 BUG_ON(item_size !=
3973 sizeof(struct btrfs_extent_item_v0));
3974 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3975 &path_change);
3976 if (ret < 0) {
3977 err = ret;
3978 break;
3979 }
3980 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3981 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3982 else
3983 flags = BTRFS_EXTENT_FLAG_DATA;
3984
3985 if (path_change) {
3986 btrfs_release_path(path);
3987
3988 path->search_commit_root = 1;
3989 path->skip_locking = 1;
3990 ret = btrfs_search_slot(NULL, rc->extent_root,
3991 &key, path, 0, 0);
3992 if (ret < 0) {
3993 err = ret;
3994 break;
3995 }
3996 BUG_ON(ret > 0);
3997 }
3998 #else
3999 BUG();
4000 #endif
4001 }
4002
4003 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4004 ret = add_tree_block(rc, &key, path, &blocks);
4005 } else if (rc->stage == UPDATE_DATA_PTRS &&
4006 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4007 ret = add_data_references(rc, &key, path, &blocks);
4008 } else {
4009 btrfs_release_path(path);
4010 ret = 0;
4011 }
4012 if (ret < 0) {
4013 err = ret;
4014 break;
4015 }
4016
4017 if (!RB_EMPTY_ROOT(&blocks)) {
4018 ret = relocate_tree_blocks(trans, rc, &blocks);
4019 if (ret < 0) {
4020 /*
4021 * if we fail to relocate tree blocks, force to update
4022 * backref cache when committing transaction.
4023 */
4024 rc->backref_cache.last_trans = trans->transid - 1;
4025
4026 if (ret != -EAGAIN) {
4027 err = ret;
4028 break;
4029 }
4030 rc->extents_found--;
4031 rc->search_start = key.objectid;
4032 }
4033 }
4034
4035 btrfs_end_transaction_throttle(trans, rc->extent_root);
4036 btrfs_btree_balance_dirty(rc->extent_root);
4037 trans = NULL;
4038
4039 if (rc->stage == MOVE_DATA_EXTENTS &&
4040 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4041 rc->found_file_extent = 1;
4042 ret = relocate_data_extent(rc->data_inode,
4043 &key, &rc->cluster);
4044 if (ret < 0) {
4045 err = ret;
4046 break;
4047 }
4048 }
4049 }
4050 if (trans && progress && err == -ENOSPC) {
4051 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
4052 rc->block_group->flags);
4053 if (ret == 1) {
4054 err = 0;
4055 progress = 0;
4056 goto restart;
4057 }
4058 }
4059
4060 btrfs_release_path(path);
4061 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
4062 GFP_NOFS);
4063
4064 if (trans) {
4065 btrfs_end_transaction_throttle(trans, rc->extent_root);
4066 btrfs_btree_balance_dirty(rc->extent_root);
4067 }
4068
4069 if (!err) {
4070 ret = relocate_file_extent_cluster(rc->data_inode,
4071 &rc->cluster);
4072 if (ret < 0)
4073 err = ret;
4074 }
4075
4076 rc->create_reloc_tree = 0;
4077 set_reloc_control(rc);
4078
4079 backref_cache_cleanup(&rc->backref_cache);
4080 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4081
4082 err = prepare_to_merge(rc, err);
4083
4084 merge_reloc_roots(rc);
4085
4086 rc->merge_reloc_tree = 0;
4087 unset_reloc_control(rc);
4088 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4089
4090 /* get rid of pinned extents */
4091 trans = btrfs_join_transaction(rc->extent_root);
4092 if (IS_ERR(trans))
4093 err = PTR_ERR(trans);
4094 else
4095 btrfs_commit_transaction(trans, rc->extent_root);
4096 out_free:
4097 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
4098 btrfs_free_path(path);
4099 return err;
4100 }
4101
4102 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4103 struct btrfs_root *root, u64 objectid)
4104 {
4105 struct btrfs_path *path;
4106 struct btrfs_inode_item *item;
4107 struct extent_buffer *leaf;
4108 int ret;
4109
4110 path = btrfs_alloc_path();
4111 if (!path)
4112 return -ENOMEM;
4113
4114 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4115 if (ret)
4116 goto out;
4117
4118 leaf = path->nodes[0];
4119 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4120 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4121 btrfs_set_inode_generation(leaf, item, 1);
4122 btrfs_set_inode_size(leaf, item, 0);
4123 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4124 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4125 BTRFS_INODE_PREALLOC);
4126 btrfs_mark_buffer_dirty(leaf);
4127 out:
4128 btrfs_free_path(path);
4129 return ret;
4130 }
4131
4132 /*
4133 * helper to create inode for data relocation.
4134 * the inode is in data relocation tree and its link count is 0
4135 */
4136 static noinline_for_stack
4137 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4138 struct btrfs_block_group_cache *group)
4139 {
4140 struct inode *inode = NULL;
4141 struct btrfs_trans_handle *trans;
4142 struct btrfs_root *root;
4143 struct btrfs_key key;
4144 u64 objectid;
4145 int err = 0;
4146
4147 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4148 if (IS_ERR(root))
4149 return ERR_CAST(root);
4150
4151 trans = btrfs_start_transaction(root, 6);
4152 if (IS_ERR(trans))
4153 return ERR_CAST(trans);
4154
4155 err = btrfs_find_free_objectid(root, &objectid);
4156 if (err)
4157 goto out;
4158
4159 err = __insert_orphan_inode(trans, root, objectid);
4160 BUG_ON(err);
4161
4162 key.objectid = objectid;
4163 key.type = BTRFS_INODE_ITEM_KEY;
4164 key.offset = 0;
4165 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
4166 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4167 BTRFS_I(inode)->index_cnt = group->key.objectid;
4168
4169 err = btrfs_orphan_add(trans, inode);
4170 out:
4171 btrfs_end_transaction(trans, root);
4172 btrfs_btree_balance_dirty(root);
4173 if (err) {
4174 if (inode)
4175 iput(inode);
4176 inode = ERR_PTR(err);
4177 }
4178 return inode;
4179 }
4180
4181 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4182 {
4183 struct reloc_control *rc;
4184
4185 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4186 if (!rc)
4187 return NULL;
4188
4189 INIT_LIST_HEAD(&rc->reloc_roots);
4190 backref_cache_init(&rc->backref_cache);
4191 mapping_tree_init(&rc->reloc_root_tree);
4192 extent_io_tree_init(&rc->processed_blocks,
4193 fs_info->btree_inode->i_mapping);
4194 return rc;
4195 }
4196
4197 /*
4198 * function to relocate all extents in a block group.
4199 */
4200 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4201 {
4202 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4203 struct reloc_control *rc;
4204 struct inode *inode;
4205 struct btrfs_path *path;
4206 int ret;
4207 int rw = 0;
4208 int err = 0;
4209
4210 rc = alloc_reloc_control(fs_info);
4211 if (!rc)
4212 return -ENOMEM;
4213
4214 rc->extent_root = extent_root;
4215
4216 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4217 BUG_ON(!rc->block_group);
4218
4219 ret = btrfs_inc_block_group_ro(extent_root, rc->block_group);
4220 if (ret) {
4221 err = ret;
4222 goto out;
4223 }
4224 rw = 1;
4225
4226 path = btrfs_alloc_path();
4227 if (!path) {
4228 err = -ENOMEM;
4229 goto out;
4230 }
4231
4232 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4233 path);
4234 btrfs_free_path(path);
4235
4236 if (!IS_ERR(inode))
4237 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4238 else
4239 ret = PTR_ERR(inode);
4240
4241 if (ret && ret != -ENOENT) {
4242 err = ret;
4243 goto out;
4244 }
4245
4246 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4247 if (IS_ERR(rc->data_inode)) {
4248 err = PTR_ERR(rc->data_inode);
4249 rc->data_inode = NULL;
4250 goto out;
4251 }
4252
4253 btrfs_info(extent_root->fs_info, "relocating block group %llu flags %llu",
4254 rc->block_group->key.objectid, rc->block_group->flags);
4255
4256 ret = btrfs_start_delalloc_roots(fs_info, 0, -1);
4257 if (ret < 0) {
4258 err = ret;
4259 goto out;
4260 }
4261 btrfs_wait_ordered_roots(fs_info, -1);
4262
4263 while (1) {
4264 mutex_lock(&fs_info->cleaner_mutex);
4265 ret = relocate_block_group(rc);
4266 mutex_unlock(&fs_info->cleaner_mutex);
4267 if (ret < 0) {
4268 err = ret;
4269 goto out;
4270 }
4271
4272 if (rc->extents_found == 0)
4273 break;
4274
4275 btrfs_info(extent_root->fs_info, "found %llu extents",
4276 rc->extents_found);
4277
4278 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4279 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4280 (u64)-1);
4281 if (ret) {
4282 err = ret;
4283 goto out;
4284 }
4285 invalidate_mapping_pages(rc->data_inode->i_mapping,
4286 0, -1);
4287 rc->stage = UPDATE_DATA_PTRS;
4288 }
4289 }
4290
4291 WARN_ON(rc->block_group->pinned > 0);
4292 WARN_ON(rc->block_group->reserved > 0);
4293 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4294 out:
4295 if (err && rw)
4296 btrfs_dec_block_group_ro(extent_root, rc->block_group);
4297 iput(rc->data_inode);
4298 btrfs_put_block_group(rc->block_group);
4299 kfree(rc);
4300 return err;
4301 }
4302
4303 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4304 {
4305 struct btrfs_trans_handle *trans;
4306 int ret, err;
4307
4308 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4309 if (IS_ERR(trans))
4310 return PTR_ERR(trans);
4311
4312 memset(&root->root_item.drop_progress, 0,
4313 sizeof(root->root_item.drop_progress));
4314 root->root_item.drop_level = 0;
4315 btrfs_set_root_refs(&root->root_item, 0);
4316 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4317 &root->root_key, &root->root_item);
4318
4319 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4320 if (err)
4321 return err;
4322 return ret;
4323 }
4324
4325 /*
4326 * recover relocation interrupted by system crash.
4327 *
4328 * this function resumes merging reloc trees with corresponding fs trees.
4329 * this is important for keeping the sharing of tree blocks
4330 */
4331 int btrfs_recover_relocation(struct btrfs_root *root)
4332 {
4333 LIST_HEAD(reloc_roots);
4334 struct btrfs_key key;
4335 struct btrfs_root *fs_root;
4336 struct btrfs_root *reloc_root;
4337 struct btrfs_path *path;
4338 struct extent_buffer *leaf;
4339 struct reloc_control *rc = NULL;
4340 struct btrfs_trans_handle *trans;
4341 int ret;
4342 int err = 0;
4343
4344 path = btrfs_alloc_path();
4345 if (!path)
4346 return -ENOMEM;
4347 path->reada = READA_BACK;
4348
4349 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4350 key.type = BTRFS_ROOT_ITEM_KEY;
4351 key.offset = (u64)-1;
4352
4353 while (1) {
4354 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4355 path, 0, 0);
4356 if (ret < 0) {
4357 err = ret;
4358 goto out;
4359 }
4360 if (ret > 0) {
4361 if (path->slots[0] == 0)
4362 break;
4363 path->slots[0]--;
4364 }
4365 leaf = path->nodes[0];
4366 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4367 btrfs_release_path(path);
4368
4369 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4370 key.type != BTRFS_ROOT_ITEM_KEY)
4371 break;
4372
4373 reloc_root = btrfs_read_fs_root(root, &key);
4374 if (IS_ERR(reloc_root)) {
4375 err = PTR_ERR(reloc_root);
4376 goto out;
4377 }
4378
4379 list_add(&reloc_root->root_list, &reloc_roots);
4380
4381 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4382 fs_root = read_fs_root(root->fs_info,
4383 reloc_root->root_key.offset);
4384 if (IS_ERR(fs_root)) {
4385 ret = PTR_ERR(fs_root);
4386 if (ret != -ENOENT) {
4387 err = ret;
4388 goto out;
4389 }
4390 ret = mark_garbage_root(reloc_root);
4391 if (ret < 0) {
4392 err = ret;
4393 goto out;
4394 }
4395 }
4396 }
4397
4398 if (key.offset == 0)
4399 break;
4400
4401 key.offset--;
4402 }
4403 btrfs_release_path(path);
4404
4405 if (list_empty(&reloc_roots))
4406 goto out;
4407
4408 rc = alloc_reloc_control(root->fs_info);
4409 if (!rc) {
4410 err = -ENOMEM;
4411 goto out;
4412 }
4413
4414 rc->extent_root = root->fs_info->extent_root;
4415
4416 set_reloc_control(rc);
4417
4418 trans = btrfs_join_transaction(rc->extent_root);
4419 if (IS_ERR(trans)) {
4420 unset_reloc_control(rc);
4421 err = PTR_ERR(trans);
4422 goto out_free;
4423 }
4424
4425 rc->merge_reloc_tree = 1;
4426
4427 while (!list_empty(&reloc_roots)) {
4428 reloc_root = list_entry(reloc_roots.next,
4429 struct btrfs_root, root_list);
4430 list_del(&reloc_root->root_list);
4431
4432 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4433 list_add_tail(&reloc_root->root_list,
4434 &rc->reloc_roots);
4435 continue;
4436 }
4437
4438 fs_root = read_fs_root(root->fs_info,
4439 reloc_root->root_key.offset);
4440 if (IS_ERR(fs_root)) {
4441 err = PTR_ERR(fs_root);
4442 goto out_free;
4443 }
4444
4445 err = __add_reloc_root(reloc_root);
4446 BUG_ON(err < 0); /* -ENOMEM or logic error */
4447 fs_root->reloc_root = reloc_root;
4448 }
4449
4450 err = btrfs_commit_transaction(trans, rc->extent_root);
4451 if (err)
4452 goto out_free;
4453
4454 merge_reloc_roots(rc);
4455
4456 unset_reloc_control(rc);
4457
4458 trans = btrfs_join_transaction(rc->extent_root);
4459 if (IS_ERR(trans))
4460 err = PTR_ERR(trans);
4461 else
4462 err = btrfs_commit_transaction(trans, rc->extent_root);
4463 out_free:
4464 kfree(rc);
4465 out:
4466 if (!list_empty(&reloc_roots))
4467 free_reloc_roots(&reloc_roots);
4468
4469 btrfs_free_path(path);
4470
4471 if (err == 0) {
4472 /* cleanup orphan inode in data relocation tree */
4473 fs_root = read_fs_root(root->fs_info,
4474 BTRFS_DATA_RELOC_TREE_OBJECTID);
4475 if (IS_ERR(fs_root))
4476 err = PTR_ERR(fs_root);
4477 else
4478 err = btrfs_orphan_cleanup(fs_root);
4479 }
4480 return err;
4481 }
4482
4483 /*
4484 * helper to add ordered checksum for data relocation.
4485 *
4486 * cloning checksum properly handles the nodatasum extents.
4487 * it also saves CPU time to re-calculate the checksum.
4488 */
4489 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4490 {
4491 struct btrfs_ordered_sum *sums;
4492 struct btrfs_ordered_extent *ordered;
4493 struct btrfs_root *root = BTRFS_I(inode)->root;
4494 int ret;
4495 u64 disk_bytenr;
4496 u64 new_bytenr;
4497 LIST_HEAD(list);
4498
4499 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4500 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4501
4502 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4503 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4504 disk_bytenr + len - 1, &list, 0);
4505 if (ret)
4506 goto out;
4507
4508 while (!list_empty(&list)) {
4509 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4510 list_del_init(&sums->list);
4511
4512 /*
4513 * We need to offset the new_bytenr based on where the csum is.
4514 * We need to do this because we will read in entire prealloc
4515 * extents but we may have written to say the middle of the
4516 * prealloc extent, so we need to make sure the csum goes with
4517 * the right disk offset.
4518 *
4519 * We can do this because the data reloc inode refers strictly
4520 * to the on disk bytes, so we don't have to worry about
4521 * disk_len vs real len like with real inodes since it's all
4522 * disk length.
4523 */
4524 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4525 sums->bytenr = new_bytenr;
4526
4527 btrfs_add_ordered_sum(inode, ordered, sums);
4528 }
4529 out:
4530 btrfs_put_ordered_extent(ordered);
4531 return ret;
4532 }
4533
4534 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4535 struct btrfs_root *root, struct extent_buffer *buf,
4536 struct extent_buffer *cow)
4537 {
4538 struct reloc_control *rc;
4539 struct backref_node *node;
4540 int first_cow = 0;
4541 int level;
4542 int ret = 0;
4543
4544 rc = root->fs_info->reloc_ctl;
4545 if (!rc)
4546 return 0;
4547
4548 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4549 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4550
4551 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4552 if (buf == root->node)
4553 __update_reloc_root(root, cow->start);
4554 }
4555
4556 level = btrfs_header_level(buf);
4557 if (btrfs_header_generation(buf) <=
4558 btrfs_root_last_snapshot(&root->root_item))
4559 first_cow = 1;
4560
4561 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4562 rc->create_reloc_tree) {
4563 WARN_ON(!first_cow && level == 0);
4564
4565 node = rc->backref_cache.path[level];
4566 BUG_ON(node->bytenr != buf->start &&
4567 node->new_bytenr != buf->start);
4568
4569 drop_node_buffer(node);
4570 extent_buffer_get(cow);
4571 node->eb = cow;
4572 node->new_bytenr = cow->start;
4573
4574 if (!node->pending) {
4575 list_move_tail(&node->list,
4576 &rc->backref_cache.pending[level]);
4577 node->pending = 1;
4578 }
4579
4580 if (first_cow)
4581 __mark_block_processed(rc, node);
4582
4583 if (first_cow && level > 0)
4584 rc->nodes_relocated += buf->len;
4585 }
4586
4587 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4588 ret = replace_file_extents(trans, rc, root, cow);
4589 return ret;
4590 }
4591
4592 /*
4593 * called before creating snapshot. it calculates metadata reservation
4594 * requried for relocating tree blocks in the snapshot
4595 */
4596 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4597 u64 *bytes_to_reserve)
4598 {
4599 struct btrfs_root *root;
4600 struct reloc_control *rc;
4601
4602 root = pending->root;
4603 if (!root->reloc_root)
4604 return;
4605
4606 rc = root->fs_info->reloc_ctl;
4607 if (!rc->merge_reloc_tree)
4608 return;
4609
4610 root = root->reloc_root;
4611 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4612 /*
4613 * relocation is in the stage of merging trees. the space
4614 * used by merging a reloc tree is twice the size of
4615 * relocated tree nodes in the worst case. half for cowing
4616 * the reloc tree, half for cowing the fs tree. the space
4617 * used by cowing the reloc tree will be freed after the
4618 * tree is dropped. if we create snapshot, cowing the fs
4619 * tree may use more space than it frees. so we need
4620 * reserve extra space.
4621 */
4622 *bytes_to_reserve += rc->nodes_relocated;
4623 }
4624
4625 /*
4626 * called after snapshot is created. migrate block reservation
4627 * and create reloc root for the newly created snapshot
4628 */
4629 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4630 struct btrfs_pending_snapshot *pending)
4631 {
4632 struct btrfs_root *root = pending->root;
4633 struct btrfs_root *reloc_root;
4634 struct btrfs_root *new_root;
4635 struct reloc_control *rc;
4636 int ret;
4637
4638 if (!root->reloc_root)
4639 return 0;
4640
4641 rc = root->fs_info->reloc_ctl;
4642 rc->merging_rsv_size += rc->nodes_relocated;
4643
4644 if (rc->merge_reloc_tree) {
4645 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4646 rc->block_rsv,
4647 rc->nodes_relocated);
4648 if (ret)
4649 return ret;
4650 }
4651
4652 new_root = pending->snap;
4653 reloc_root = create_reloc_root(trans, root->reloc_root,
4654 new_root->root_key.objectid);
4655 if (IS_ERR(reloc_root))
4656 return PTR_ERR(reloc_root);
4657
4658 ret = __add_reloc_root(reloc_root);
4659 BUG_ON(ret < 0);
4660 new_root->reloc_root = reloc_root;
4661
4662 if (rc->create_reloc_tree)
4663 ret = clone_backref_node(trans, rc, root, reloc_root);
4664 return ret;
4665 }
Linux kernel - Deliverables
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