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kvm: nVMX: Fix kernel panics induced by illegal INVEPT/INVVPID types
[linux/fpc-iii.git] / fs / btrfs / relocation.c
blob0ec8ffa37ab09dce21e6d2806c938cce6d4d17a7
1 /*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33 #include "inode-map.h"
34 #include "qgroup.h"
35
36 /*
37 * backref_node, mapping_node and tree_block start with this
38 */
39 struct tree_entry {
40 struct rb_node rb_node;
41 u64 bytenr;
42 };
43
44 /*
45 * present a tree block in the backref cache
46 */
47 struct backref_node {
48 struct rb_node rb_node;
49 u64 bytenr;
50
51 u64 new_bytenr;
52 /* objectid of tree block owner, can be not uptodate */
53 u64 owner;
54 /* link to pending, changed or detached list */
55 struct list_head list;
56 /* list of upper level blocks reference this block */
57 struct list_head upper;
58 /* list of child blocks in the cache */
59 struct list_head lower;
60 /* NULL if this node is not tree root */
61 struct btrfs_root *root;
62 /* extent buffer got by COW the block */
63 struct extent_buffer *eb;
64 /* level of tree block */
65 unsigned int level:8;
66 /* is the block in non-reference counted tree */
67 unsigned int cowonly:1;
68 /* 1 if no child node in the cache */
69 unsigned int lowest:1;
70 /* is the extent buffer locked */
71 unsigned int locked:1;
72 /* has the block been processed */
73 unsigned int processed:1;
74 /* have backrefs of this block been checked */
75 unsigned int checked:1;
76 /*
77 * 1 if corresponding block has been cowed but some upper
78 * level block pointers may not point to the new location
79 */
80 unsigned int pending:1;
81 /*
82 * 1 if the backref node isn't connected to any other
83 * backref node.
84 */
85 unsigned int detached:1;
86 };
87
88 /*
89 * present a block pointer in the backref cache
90 */
91 struct backref_edge {
92 struct list_head list[2];
93 struct backref_node *node[2];
94 };
95
96 #define LOWER 0
97 #define UPPER 1
98 #define RELOCATION_RESERVED_NODES 256
99
100 struct backref_cache {
101 /* red black tree of all backref nodes in the cache */
102 struct rb_root rb_root;
103 /* for passing backref nodes to btrfs_reloc_cow_block */
104 struct backref_node *path[BTRFS_MAX_LEVEL];
105 /*
106 * list of blocks that have been cowed but some block
107 * pointers in upper level blocks may not reflect the
108 * new location
109 */
110 struct list_head pending[BTRFS_MAX_LEVEL];
111 /* list of backref nodes with no child node */
112 struct list_head leaves;
113 /* list of blocks that have been cowed in current transaction */
114 struct list_head changed;
115 /* list of detached backref node. */
116 struct list_head detached;
117
118 u64 last_trans;
119
120 int nr_nodes;
121 int nr_edges;
122 };
123
124 /*
125 * map address of tree root to tree
126 */
127 struct mapping_node {
128 struct rb_node rb_node;
129 u64 bytenr;
130 void *data;
131 };
132
133 struct mapping_tree {
134 struct rb_root rb_root;
135 spinlock_t lock;
136 };
137
138 /*
139 * present a tree block to process
140 */
141 struct tree_block {
142 struct rb_node rb_node;
143 u64 bytenr;
144 struct btrfs_key key;
145 unsigned int level:8;
146 unsigned int key_ready:1;
147 };
148
149 #define MAX_EXTENTS 128
150
151 struct file_extent_cluster {
152 u64 start;
153 u64 end;
154 u64 boundary[MAX_EXTENTS];
155 unsigned int nr;
156 };
157
158 struct reloc_control {
159 /* block group to relocate */
160 struct btrfs_block_group_cache *block_group;
161 /* extent tree */
162 struct btrfs_root *extent_root;
163 /* inode for moving data */
164 struct inode *data_inode;
165
166 struct btrfs_block_rsv *block_rsv;
167
168 struct backref_cache backref_cache;
169
170 struct file_extent_cluster cluster;
171 /* tree blocks have been processed */
172 struct extent_io_tree processed_blocks;
173 /* map start of tree root to corresponding reloc tree */
174 struct mapping_tree reloc_root_tree;
175 /* list of reloc trees */
176 struct list_head reloc_roots;
177 /* size of metadata reservation for merging reloc trees */
178 u64 merging_rsv_size;
179 /* size of relocated tree nodes */
180 u64 nodes_relocated;
181 /* reserved size for block group relocation*/
182 u64 reserved_bytes;
183
184 u64 search_start;
185 u64 extents_found;
186
187 unsigned int stage:8;
188 unsigned int create_reloc_tree:1;
189 unsigned int merge_reloc_tree:1;
190 unsigned int found_file_extent:1;
191 };
192
193 /* stages of data relocation */
194 #define MOVE_DATA_EXTENTS 0
195 #define UPDATE_DATA_PTRS 1
196
197 static void remove_backref_node(struct backref_cache *cache,
198 struct backref_node *node);
199 static void __mark_block_processed(struct reloc_control *rc,
200 struct backref_node *node);
201
202 static void mapping_tree_init(struct mapping_tree *tree)
203 {
204 tree->rb_root = RB_ROOT;
205 spin_lock_init(&tree->lock);
206 }
207
208 static void backref_cache_init(struct backref_cache *cache)
209 {
210 int i;
211 cache->rb_root = RB_ROOT;
212 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
213 INIT_LIST_HEAD(&cache->pending[i]);
214 INIT_LIST_HEAD(&cache->changed);
215 INIT_LIST_HEAD(&cache->detached);
216 INIT_LIST_HEAD(&cache->leaves);
217 }
218
219 static void backref_cache_cleanup(struct backref_cache *cache)
220 {
221 struct backref_node *node;
222 int i;
223
224 while (!list_empty(&cache->detached)) {
225 node = list_entry(cache->detached.next,
226 struct backref_node, list);
227 remove_backref_node(cache, node);
228 }
229
230 while (!list_empty(&cache->leaves)) {
231 node = list_entry(cache->leaves.next,
232 struct backref_node, lower);
233 remove_backref_node(cache, node);
234 }
235
236 cache->last_trans = 0;
237
238 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
239 ASSERT(list_empty(&cache->pending[i]));
240 ASSERT(list_empty(&cache->changed));
241 ASSERT(list_empty(&cache->detached));
242 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
243 ASSERT(!cache->nr_nodes);
244 ASSERT(!cache->nr_edges);
245 }
246
247 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
248 {
249 struct backref_node *node;
250
251 node = kzalloc(sizeof(*node), GFP_NOFS);
252 if (node) {
253 INIT_LIST_HEAD(&node->list);
254 INIT_LIST_HEAD(&node->upper);
255 INIT_LIST_HEAD(&node->lower);
256 RB_CLEAR_NODE(&node->rb_node);
257 cache->nr_nodes++;
258 }
259 return node;
260 }
261
262 static void free_backref_node(struct backref_cache *cache,
263 struct backref_node *node)
264 {
265 if (node) {
266 cache->nr_nodes--;
267 kfree(node);
268 }
269 }
270
271 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
272 {
273 struct backref_edge *edge;
274
275 edge = kzalloc(sizeof(*edge), GFP_NOFS);
276 if (edge)
277 cache->nr_edges++;
278 return edge;
279 }
280
281 static void free_backref_edge(struct backref_cache *cache,
282 struct backref_edge *edge)
283 {
284 if (edge) {
285 cache->nr_edges--;
286 kfree(edge);
287 }
288 }
289
290 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
291 struct rb_node *node)
292 {
293 struct rb_node **p = &root->rb_node;
294 struct rb_node *parent = NULL;
295 struct tree_entry *entry;
296
297 while (*p) {
298 parent = *p;
299 entry = rb_entry(parent, struct tree_entry, rb_node);
300
301 if (bytenr < entry->bytenr)
302 p = &(*p)->rb_left;
303 else if (bytenr > entry->bytenr)
304 p = &(*p)->rb_right;
305 else
306 return parent;
307 }
308
309 rb_link_node(node, parent, p);
310 rb_insert_color(node, root);
311 return NULL;
312 }
313
314 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
315 {
316 struct rb_node *n = root->rb_node;
317 struct tree_entry *entry;
318
319 while (n) {
320 entry = rb_entry(n, struct tree_entry, rb_node);
321
322 if (bytenr < entry->bytenr)
323 n = n->rb_left;
324 else if (bytenr > entry->bytenr)
325 n = n->rb_right;
326 else
327 return n;
328 }
329 return NULL;
330 }
331
332 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
333 {
334
335 struct btrfs_fs_info *fs_info = NULL;
336 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
337 rb_node);
338 if (bnode->root)
339 fs_info = bnode->root->fs_info;
340 btrfs_panic(fs_info, errno,
341 "Inconsistency in backref cache found at offset %llu",
342 bytenr);
343 }
344
345 /*
346 * walk up backref nodes until reach node presents tree root
347 */
348 static struct backref_node *walk_up_backref(struct backref_node *node,
349 struct backref_edge *edges[],
350 int *index)
351 {
352 struct backref_edge *edge;
353 int idx = *index;
354
355 while (!list_empty(&node->upper)) {
356 edge = list_entry(node->upper.next,
357 struct backref_edge, list[LOWER]);
358 edges[idx++] = edge;
359 node = edge->node[UPPER];
360 }
361 BUG_ON(node->detached);
362 *index = idx;
363 return node;
364 }
365
366 /*
367 * walk down backref nodes to find start of next reference path
368 */
369 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
370 int *index)
371 {
372 struct backref_edge *edge;
373 struct backref_node *lower;
374 int idx = *index;
375
376 while (idx > 0) {
377 edge = edges[idx - 1];
378 lower = edge->node[LOWER];
379 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
380 idx--;
381 continue;
382 }
383 edge = list_entry(edge->list[LOWER].next,
384 struct backref_edge, list[LOWER]);
385 edges[idx - 1] = edge;
386 *index = idx;
387 return edge->node[UPPER];
388 }
389 *index = 0;
390 return NULL;
391 }
392
393 static void unlock_node_buffer(struct backref_node *node)
394 {
395 if (node->locked) {
396 btrfs_tree_unlock(node->eb);
397 node->locked = 0;
398 }
399 }
400
401 static void drop_node_buffer(struct backref_node *node)
402 {
403 if (node->eb) {
404 unlock_node_buffer(node);
405 free_extent_buffer(node->eb);
406 node->eb = NULL;
407 }
408 }
409
410 static void drop_backref_node(struct backref_cache *tree,
411 struct backref_node *node)
412 {
413 BUG_ON(!list_empty(&node->upper));
414
415 drop_node_buffer(node);
416 list_del(&node->list);
417 list_del(&node->lower);
418 if (!RB_EMPTY_NODE(&node->rb_node))
419 rb_erase(&node->rb_node, &tree->rb_root);
420 free_backref_node(tree, node);
421 }
422
423 /*
424 * remove a backref node from the backref cache
425 */
426 static void remove_backref_node(struct backref_cache *cache,
427 struct backref_node *node)
428 {
429 struct backref_node *upper;
430 struct backref_edge *edge;
431
432 if (!node)
433 return;
434
435 BUG_ON(!node->lowest && !node->detached);
436 while (!list_empty(&node->upper)) {
437 edge = list_entry(node->upper.next, struct backref_edge,
438 list[LOWER]);
439 upper = edge->node[UPPER];
440 list_del(&edge->list[LOWER]);
441 list_del(&edge->list[UPPER]);
442 free_backref_edge(cache, edge);
443
444 if (RB_EMPTY_NODE(&upper->rb_node)) {
445 BUG_ON(!list_empty(&node->upper));
446 drop_backref_node(cache, node);
447 node = upper;
448 node->lowest = 1;
449 continue;
450 }
451 /*
452 * add the node to leaf node list if no other
453 * child block cached.
454 */
455 if (list_empty(&upper->lower)) {
456 list_add_tail(&upper->lower, &cache->leaves);
457 upper->lowest = 1;
458 }
459 }
460
461 drop_backref_node(cache, node);
462 }
463
464 static void update_backref_node(struct backref_cache *cache,
465 struct backref_node *node, u64 bytenr)
466 {
467 struct rb_node *rb_node;
468 rb_erase(&node->rb_node, &cache->rb_root);
469 node->bytenr = bytenr;
470 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
471 if (rb_node)
472 backref_tree_panic(rb_node, -EEXIST, bytenr);
473 }
474
475 /*
476 * update backref cache after a transaction commit
477 */
478 static int update_backref_cache(struct btrfs_trans_handle *trans,
479 struct backref_cache *cache)
480 {
481 struct backref_node *node;
482 int level = 0;
483
484 if (cache->last_trans == 0) {
485 cache->last_trans = trans->transid;
486 return 0;
487 }
488
489 if (cache->last_trans == trans->transid)
490 return 0;
491
492 /*
493 * detached nodes are used to avoid unnecessary backref
494 * lookup. transaction commit changes the extent tree.
495 * so the detached nodes are no longer useful.
496 */
497 while (!list_empty(&cache->detached)) {
498 node = list_entry(cache->detached.next,
499 struct backref_node, list);
500 remove_backref_node(cache, node);
501 }
502
503 while (!list_empty(&cache->changed)) {
504 node = list_entry(cache->changed.next,
505 struct backref_node, list);
506 list_del_init(&node->list);
507 BUG_ON(node->pending);
508 update_backref_node(cache, node, node->new_bytenr);
509 }
510
511 /*
512 * some nodes can be left in the pending list if there were
513 * errors during processing the pending nodes.
514 */
515 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
516 list_for_each_entry(node, &cache->pending[level], list) {
517 BUG_ON(!node->pending);
518 if (node->bytenr == node->new_bytenr)
519 continue;
520 update_backref_node(cache, node, node->new_bytenr);
521 }
522 }
523
524 cache->last_trans = 0;
525 return 1;
526 }
527
528
529 static int should_ignore_root(struct btrfs_root *root)
530 {
531 struct btrfs_root *reloc_root;
532
533 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
534 return 0;
535
536 reloc_root = root->reloc_root;
537 if (!reloc_root)
538 return 0;
539
540 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
541 root->fs_info->running_transaction->transid - 1)
542 return 0;
543 /*
544 * if there is reloc tree and it was created in previous
545 * transaction backref lookup can find the reloc tree,
546 * so backref node for the fs tree root is useless for
547 * relocation.
548 */
549 return 1;
550 }
551 /*
552 * find reloc tree by address of tree root
553 */
554 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
555 u64 bytenr)
556 {
557 struct rb_node *rb_node;
558 struct mapping_node *node;
559 struct btrfs_root *root = NULL;
560
561 spin_lock(&rc->reloc_root_tree.lock);
562 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
563 if (rb_node) {
564 node = rb_entry(rb_node, struct mapping_node, rb_node);
565 root = (struct btrfs_root *)node->data;
566 }
567 spin_unlock(&rc->reloc_root_tree.lock);
568 return root;
569 }
570
571 static int is_cowonly_root(u64 root_objectid)
572 {
573 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
574 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
575 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
576 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
577 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
578 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
579 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
580 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
581 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
582 return 1;
583 return 0;
584 }
585
586 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
587 u64 root_objectid)
588 {
589 struct btrfs_key key;
590
591 key.objectid = root_objectid;
592 key.type = BTRFS_ROOT_ITEM_KEY;
593 if (is_cowonly_root(root_objectid))
594 key.offset = 0;
595 else
596 key.offset = (u64)-1;
597
598 return btrfs_get_fs_root(fs_info, &key, false);
599 }
600
601 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
602 static noinline_for_stack
603 struct btrfs_root *find_tree_root(struct reloc_control *rc,
604 struct extent_buffer *leaf,
605 struct btrfs_extent_ref_v0 *ref0)
606 {
607 struct btrfs_root *root;
608 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
609 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
610
611 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
612
613 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
614 BUG_ON(IS_ERR(root));
615
616 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
617 generation != btrfs_root_generation(&root->root_item))
618 return NULL;
619
620 return root;
621 }
622 #endif
623
624 static noinline_for_stack
625 int find_inline_backref(struct extent_buffer *leaf, int slot,
626 unsigned long *ptr, unsigned long *end)
627 {
628 struct btrfs_key key;
629 struct btrfs_extent_item *ei;
630 struct btrfs_tree_block_info *bi;
631 u32 item_size;
632
633 btrfs_item_key_to_cpu(leaf, &key, slot);
634
635 item_size = btrfs_item_size_nr(leaf, slot);
636 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
637 if (item_size < sizeof(*ei)) {
638 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
639 return 1;
640 }
641 #endif
642 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
643 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
644 BTRFS_EXTENT_FLAG_TREE_BLOCK));
645
646 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
647 item_size <= sizeof(*ei) + sizeof(*bi)) {
648 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
649 return 1;
650 }
651 if (key.type == BTRFS_METADATA_ITEM_KEY &&
652 item_size <= sizeof(*ei)) {
653 WARN_ON(item_size < sizeof(*ei));
654 return 1;
655 }
656
657 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
658 bi = (struct btrfs_tree_block_info *)(ei + 1);
659 *ptr = (unsigned long)(bi + 1);
660 } else {
661 *ptr = (unsigned long)(ei + 1);
662 }
663 *end = (unsigned long)ei + item_size;
664 return 0;
665 }
666
667 /*
668 * build backref tree for a given tree block. root of the backref tree
669 * corresponds the tree block, leaves of the backref tree correspond
670 * roots of b-trees that reference the tree block.
671 *
672 * the basic idea of this function is check backrefs of a given block
673 * to find upper level blocks that reference the block, and then check
674 * backrefs of these upper level blocks recursively. the recursion stop
675 * when tree root is reached or backrefs for the block is cached.
676 *
677 * NOTE: if we find backrefs for a block are cached, we know backrefs
678 * for all upper level blocks that directly/indirectly reference the
679 * block are also cached.
680 */
681 static noinline_for_stack
682 struct backref_node *build_backref_tree(struct reloc_control *rc,
683 struct btrfs_key *node_key,
684 int level, u64 bytenr)
685 {
686 struct backref_cache *cache = &rc->backref_cache;
687 struct btrfs_path *path1;
688 struct btrfs_path *path2;
689 struct extent_buffer *eb;
690 struct btrfs_root *root;
691 struct backref_node *cur;
692 struct backref_node *upper;
693 struct backref_node *lower;
694 struct backref_node *node = NULL;
695 struct backref_node *exist = NULL;
696 struct backref_edge *edge;
697 struct rb_node *rb_node;
698 struct btrfs_key key;
699 unsigned long end;
700 unsigned long ptr;
701 LIST_HEAD(list);
702 LIST_HEAD(useless);
703 int cowonly;
704 int ret;
705 int err = 0;
706 bool need_check = true;
707
708 path1 = btrfs_alloc_path();
709 path2 = btrfs_alloc_path();
710 if (!path1 || !path2) {
711 err = -ENOMEM;
712 goto out;
713 }
714 path1->reada = READA_FORWARD;
715 path2->reada = READA_FORWARD;
716
717 node = alloc_backref_node(cache);
718 if (!node) {
719 err = -ENOMEM;
720 goto out;
721 }
722
723 node->bytenr = bytenr;
724 node->level = level;
725 node->lowest = 1;
726 cur = node;
727 again:
728 end = 0;
729 ptr = 0;
730 key.objectid = cur->bytenr;
731 key.type = BTRFS_METADATA_ITEM_KEY;
732 key.offset = (u64)-1;
733
734 path1->search_commit_root = 1;
735 path1->skip_locking = 1;
736 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
737 0, 0);
738 if (ret < 0) {
739 err = ret;
740 goto out;
741 }
742 ASSERT(ret);
743 ASSERT(path1->slots[0]);
744
745 path1->slots[0]--;
746
747 WARN_ON(cur->checked);
748 if (!list_empty(&cur->upper)) {
749 /*
750 * the backref was added previously when processing
751 * backref of type BTRFS_TREE_BLOCK_REF_KEY
752 */
753 ASSERT(list_is_singular(&cur->upper));
754 edge = list_entry(cur->upper.next, struct backref_edge,
755 list[LOWER]);
756 ASSERT(list_empty(&edge->list[UPPER]));
757 exist = edge->node[UPPER];
758 /*
759 * add the upper level block to pending list if we need
760 * check its backrefs
761 */
762 if (!exist->checked)
763 list_add_tail(&edge->list[UPPER], &list);
764 } else {
765 exist = NULL;
766 }
767
768 while (1) {
769 cond_resched();
770 eb = path1->nodes[0];
771
772 if (ptr >= end) {
773 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
774 ret = btrfs_next_leaf(rc->extent_root, path1);
775 if (ret < 0) {
776 err = ret;
777 goto out;
778 }
779 if (ret > 0)
780 break;
781 eb = path1->nodes[0];
782 }
783
784 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
785 if (key.objectid != cur->bytenr) {
786 WARN_ON(exist);
787 break;
788 }
789
790 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
791 key.type == BTRFS_METADATA_ITEM_KEY) {
792 ret = find_inline_backref(eb, path1->slots[0],
793 &ptr, &end);
794 if (ret)
795 goto next;
796 }
797 }
798
799 if (ptr < end) {
800 /* update key for inline back ref */
801 struct btrfs_extent_inline_ref *iref;
802 iref = (struct btrfs_extent_inline_ref *)ptr;
803 key.type = btrfs_extent_inline_ref_type(eb, iref);
804 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
805 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
806 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
807 }
808
809 if (exist &&
810 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
811 exist->owner == key.offset) ||
812 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
813 exist->bytenr == key.offset))) {
814 exist = NULL;
815 goto next;
816 }
817
818 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
819 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
820 key.type == BTRFS_EXTENT_REF_V0_KEY) {
821 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
822 struct btrfs_extent_ref_v0 *ref0;
823 ref0 = btrfs_item_ptr(eb, path1->slots[0],
824 struct btrfs_extent_ref_v0);
825 if (key.objectid == key.offset) {
826 root = find_tree_root(rc, eb, ref0);
827 if (root && !should_ignore_root(root))
828 cur->root = root;
829 else
830 list_add(&cur->list, &useless);
831 break;
832 }
833 if (is_cowonly_root(btrfs_ref_root_v0(eb,
834 ref0)))
835 cur->cowonly = 1;
836 }
837 #else
838 ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
839 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
840 #endif
841 if (key.objectid == key.offset) {
842 /*
843 * only root blocks of reloc trees use
844 * backref of this type.
845 */
846 root = find_reloc_root(rc, cur->bytenr);
847 ASSERT(root);
848 cur->root = root;
849 break;
850 }
851
852 edge = alloc_backref_edge(cache);
853 if (!edge) {
854 err = -ENOMEM;
855 goto out;
856 }
857 rb_node = tree_search(&cache->rb_root, key.offset);
858 if (!rb_node) {
859 upper = alloc_backref_node(cache);
860 if (!upper) {
861 free_backref_edge(cache, edge);
862 err = -ENOMEM;
863 goto out;
864 }
865 upper->bytenr = key.offset;
866 upper->level = cur->level + 1;
867 /*
868 * backrefs for the upper level block isn't
869 * cached, add the block to pending list
870 */
871 list_add_tail(&edge->list[UPPER], &list);
872 } else {
873 upper = rb_entry(rb_node, struct backref_node,
874 rb_node);
875 ASSERT(upper->checked);
876 INIT_LIST_HEAD(&edge->list[UPPER]);
877 }
878 list_add_tail(&edge->list[LOWER], &cur->upper);
879 edge->node[LOWER] = cur;
880 edge->node[UPPER] = upper;
881
882 goto next;
883 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
884 goto next;
885 }
886
887 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
888 root = read_fs_root(rc->extent_root->fs_info, key.offset);
889 if (IS_ERR(root)) {
890 err = PTR_ERR(root);
891 goto out;
892 }
893
894 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
895 cur->cowonly = 1;
896
897 if (btrfs_root_level(&root->root_item) == cur->level) {
898 /* tree root */
899 ASSERT(btrfs_root_bytenr(&root->root_item) ==
900 cur->bytenr);
901 if (should_ignore_root(root))
902 list_add(&cur->list, &useless);
903 else
904 cur->root = root;
905 break;
906 }
907
908 level = cur->level + 1;
909
910 /*
911 * searching the tree to find upper level blocks
912 * reference the block.
913 */
914 path2->search_commit_root = 1;
915 path2->skip_locking = 1;
916 path2->lowest_level = level;
917 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
918 path2->lowest_level = 0;
919 if (ret < 0) {
920 err = ret;
921 goto out;
922 }
923 if (ret > 0 && path2->slots[level] > 0)
924 path2->slots[level]--;
925
926 eb = path2->nodes[level];
927 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
928 cur->bytenr) {
929 btrfs_err(root->fs_info,
930 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
931 cur->bytenr, level - 1, root->objectid,
932 node_key->objectid, node_key->type,
933 node_key->offset);
934 err = -ENOENT;
935 goto out;
936 }
937 lower = cur;
938 need_check = true;
939 for (; level < BTRFS_MAX_LEVEL; level++) {
940 if (!path2->nodes[level]) {
941 ASSERT(btrfs_root_bytenr(&root->root_item) ==
942 lower->bytenr);
943 if (should_ignore_root(root))
944 list_add(&lower->list, &useless);
945 else
946 lower->root = root;
947 break;
948 }
949
950 edge = alloc_backref_edge(cache);
951 if (!edge) {
952 err = -ENOMEM;
953 goto out;
954 }
955
956 eb = path2->nodes[level];
957 rb_node = tree_search(&cache->rb_root, eb->start);
958 if (!rb_node) {
959 upper = alloc_backref_node(cache);
960 if (!upper) {
961 free_backref_edge(cache, edge);
962 err = -ENOMEM;
963 goto out;
964 }
965 upper->bytenr = eb->start;
966 upper->owner = btrfs_header_owner(eb);
967 upper->level = lower->level + 1;
968 if (!test_bit(BTRFS_ROOT_REF_COWS,
969 &root->state))
970 upper->cowonly = 1;
971
972 /*
973 * if we know the block isn't shared
974 * we can void checking its backrefs.
975 */
976 if (btrfs_block_can_be_shared(root, eb))
977 upper->checked = 0;
978 else
979 upper->checked = 1;
980
981 /*
982 * add the block to pending list if we
983 * need check its backrefs, we only do this once
984 * while walking up a tree as we will catch
985 * anything else later on.
986 */
987 if (!upper->checked && need_check) {
988 need_check = false;
989 list_add_tail(&edge->list[UPPER],
990 &list);
991 } else {
992 if (upper->checked)
993 need_check = true;
994 INIT_LIST_HEAD(&edge->list[UPPER]);
995 }
996 } else {
997 upper = rb_entry(rb_node, struct backref_node,
998 rb_node);
999 ASSERT(upper->checked);
1000 INIT_LIST_HEAD(&edge->list[UPPER]);
1001 if (!upper->owner)
1002 upper->owner = btrfs_header_owner(eb);
1003 }
1004 list_add_tail(&edge->list[LOWER], &lower->upper);
1005 edge->node[LOWER] = lower;
1006 edge->node[UPPER] = upper;
1007
1008 if (rb_node)
1009 break;
1010 lower = upper;
1011 upper = NULL;
1012 }
1013 btrfs_release_path(path2);
1014 next:
1015 if (ptr < end) {
1016 ptr += btrfs_extent_inline_ref_size(key.type);
1017 if (ptr >= end) {
1018 WARN_ON(ptr > end);
1019 ptr = 0;
1020 end = 0;
1021 }
1022 }
1023 if (ptr >= end)
1024 path1->slots[0]++;
1025 }
1026 btrfs_release_path(path1);
1027
1028 cur->checked = 1;
1029 WARN_ON(exist);
1030
1031 /* the pending list isn't empty, take the first block to process */
1032 if (!list_empty(&list)) {
1033 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1034 list_del_init(&edge->list[UPPER]);
1035 cur = edge->node[UPPER];
1036 goto again;
1037 }
1038
1039 /*
1040 * everything goes well, connect backref nodes and insert backref nodes
1041 * into the cache.
1042 */
1043 ASSERT(node->checked);
1044 cowonly = node->cowonly;
1045 if (!cowonly) {
1046 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1047 &node->rb_node);
1048 if (rb_node)
1049 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1050 list_add_tail(&node->lower, &cache->leaves);
1051 }
1052
1053 list_for_each_entry(edge, &node->upper, list[LOWER])
1054 list_add_tail(&edge->list[UPPER], &list);
1055
1056 while (!list_empty(&list)) {
1057 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1058 list_del_init(&edge->list[UPPER]);
1059 upper = edge->node[UPPER];
1060 if (upper->detached) {
1061 list_del(&edge->list[LOWER]);
1062 lower = edge->node[LOWER];
1063 free_backref_edge(cache, edge);
1064 if (list_empty(&lower->upper))
1065 list_add(&lower->list, &useless);
1066 continue;
1067 }
1068
1069 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1070 if (upper->lowest) {
1071 list_del_init(&upper->lower);
1072 upper->lowest = 0;
1073 }
1074
1075 list_add_tail(&edge->list[UPPER], &upper->lower);
1076 continue;
1077 }
1078
1079 if (!upper->checked) {
1080 /*
1081 * Still want to blow up for developers since this is a
1082 * logic bug.
1083 */
1084 ASSERT(0);
1085 err = -EINVAL;
1086 goto out;
1087 }
1088 if (cowonly != upper->cowonly) {
1089 ASSERT(0);
1090 err = -EINVAL;
1091 goto out;
1092 }
1093
1094 if (!cowonly) {
1095 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1096 &upper->rb_node);
1097 if (rb_node)
1098 backref_tree_panic(rb_node, -EEXIST,
1099 upper->bytenr);
1100 }
1101
1102 list_add_tail(&edge->list[UPPER], &upper->lower);
1103
1104 list_for_each_entry(edge, &upper->upper, list[LOWER])
1105 list_add_tail(&edge->list[UPPER], &list);
1106 }
1107 /*
1108 * process useless backref nodes. backref nodes for tree leaves
1109 * are deleted from the cache. backref nodes for upper level
1110 * tree blocks are left in the cache to avoid unnecessary backref
1111 * lookup.
1112 */
1113 while (!list_empty(&useless)) {
1114 upper = list_entry(useless.next, struct backref_node, list);
1115 list_del_init(&upper->list);
1116 ASSERT(list_empty(&upper->upper));
1117 if (upper == node)
1118 node = NULL;
1119 if (upper->lowest) {
1120 list_del_init(&upper->lower);
1121 upper->lowest = 0;
1122 }
1123 while (!list_empty(&upper->lower)) {
1124 edge = list_entry(upper->lower.next,
1125 struct backref_edge, list[UPPER]);
1126 list_del(&edge->list[UPPER]);
1127 list_del(&edge->list[LOWER]);
1128 lower = edge->node[LOWER];
1129 free_backref_edge(cache, edge);
1130
1131 if (list_empty(&lower->upper))
1132 list_add(&lower->list, &useless);
1133 }
1134 __mark_block_processed(rc, upper);
1135 if (upper->level > 0) {
1136 list_add(&upper->list, &cache->detached);
1137 upper->detached = 1;
1138 } else {
1139 rb_erase(&upper->rb_node, &cache->rb_root);
1140 free_backref_node(cache, upper);
1141 }
1142 }
1143 out:
1144 btrfs_free_path(path1);
1145 btrfs_free_path(path2);
1146 if (err) {
1147 while (!list_empty(&useless)) {
1148 lower = list_entry(useless.next,
1149 struct backref_node, list);
1150 list_del_init(&lower->list);
1151 }
1152 while (!list_empty(&list)) {
1153 edge = list_first_entry(&list, struct backref_edge,
1154 list[UPPER]);
1155 list_del(&edge->list[UPPER]);
1156 list_del(&edge->list[LOWER]);
1157 lower = edge->node[LOWER];
1158 upper = edge->node[UPPER];
1159 free_backref_edge(cache, edge);
1160
1161 /*
1162 * Lower is no longer linked to any upper backref nodes
1163 * and isn't in the cache, we can free it ourselves.
1164 */
1165 if (list_empty(&lower->upper) &&
1166 RB_EMPTY_NODE(&lower->rb_node))
1167 list_add(&lower->list, &useless);
1168
1169 if (!RB_EMPTY_NODE(&upper->rb_node))
1170 continue;
1171
1172 /* Add this guy's upper edges to the list to process */
1173 list_for_each_entry(edge, &upper->upper, list[LOWER])
1174 list_add_tail(&edge->list[UPPER], &list);
1175 if (list_empty(&upper->upper))
1176 list_add(&upper->list, &useless);
1177 }
1178
1179 while (!list_empty(&useless)) {
1180 lower = list_entry(useless.next,
1181 struct backref_node, list);
1182 list_del_init(&lower->list);
1183 if (lower == node)
1184 node = NULL;
1185 free_backref_node(cache, lower);
1186 }
1187
1188 free_backref_node(cache, node);
1189 return ERR_PTR(err);
1190 }
1191 ASSERT(!node || !node->detached);
1192 return node;
1193 }
1194
1195 /*
1196 * helper to add backref node for the newly created snapshot.
1197 * the backref node is created by cloning backref node that
1198 * corresponds to root of source tree
1199 */
1200 static int clone_backref_node(struct btrfs_trans_handle *trans,
1201 struct reloc_control *rc,
1202 struct btrfs_root *src,
1203 struct btrfs_root *dest)
1204 {
1205 struct btrfs_root *reloc_root = src->reloc_root;
1206 struct backref_cache *cache = &rc->backref_cache;
1207 struct backref_node *node = NULL;
1208 struct backref_node *new_node;
1209 struct backref_edge *edge;
1210 struct backref_edge *new_edge;
1211 struct rb_node *rb_node;
1212
1213 if (cache->last_trans > 0)
1214 update_backref_cache(trans, cache);
1215
1216 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1217 if (rb_node) {
1218 node = rb_entry(rb_node, struct backref_node, rb_node);
1219 if (node->detached)
1220 node = NULL;
1221 else
1222 BUG_ON(node->new_bytenr != reloc_root->node->start);
1223 }
1224
1225 if (!node) {
1226 rb_node = tree_search(&cache->rb_root,
1227 reloc_root->commit_root->start);
1228 if (rb_node) {
1229 node = rb_entry(rb_node, struct backref_node,
1230 rb_node);
1231 BUG_ON(node->detached);
1232 }
1233 }
1234
1235 if (!node)
1236 return 0;
1237
1238 new_node = alloc_backref_node(cache);
1239 if (!new_node)
1240 return -ENOMEM;
1241
1242 new_node->bytenr = dest->node->start;
1243 new_node->level = node->level;
1244 new_node->lowest = node->lowest;
1245 new_node->checked = 1;
1246 new_node->root = dest;
1247
1248 if (!node->lowest) {
1249 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1250 new_edge = alloc_backref_edge(cache);
1251 if (!new_edge)
1252 goto fail;
1253
1254 new_edge->node[UPPER] = new_node;
1255 new_edge->node[LOWER] = edge->node[LOWER];
1256 list_add_tail(&new_edge->list[UPPER],
1257 &new_node->lower);
1258 }
1259 } else {
1260 list_add_tail(&new_node->lower, &cache->leaves);
1261 }
1262
1263 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1264 &new_node->rb_node);
1265 if (rb_node)
1266 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1267
1268 if (!new_node->lowest) {
1269 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1270 list_add_tail(&new_edge->list[LOWER],
1271 &new_edge->node[LOWER]->upper);
1272 }
1273 }
1274 return 0;
1275 fail:
1276 while (!list_empty(&new_node->lower)) {
1277 new_edge = list_entry(new_node->lower.next,
1278 struct backref_edge, list[UPPER]);
1279 list_del(&new_edge->list[UPPER]);
1280 free_backref_edge(cache, new_edge);
1281 }
1282 free_backref_node(cache, new_node);
1283 return -ENOMEM;
1284 }
1285
1286 /*
1287 * helper to add 'address of tree root -> reloc tree' mapping
1288 */
1289 static int __must_check __add_reloc_root(struct btrfs_root *root)
1290 {
1291 struct rb_node *rb_node;
1292 struct mapping_node *node;
1293 struct reloc_control *rc = root->fs_info->reloc_ctl;
1294
1295 node = kmalloc(sizeof(*node), GFP_NOFS);
1296 if (!node)
1297 return -ENOMEM;
1298
1299 node->bytenr = root->node->start;
1300 node->data = root;
1301
1302 spin_lock(&rc->reloc_root_tree.lock);
1303 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1304 node->bytenr, &node->rb_node);
1305 spin_unlock(&rc->reloc_root_tree.lock);
1306 if (rb_node) {
1307 btrfs_panic(root->fs_info, -EEXIST,
1308 "Duplicate root found for start=%llu while inserting into relocation tree",
1309 node->bytenr);
1310 kfree(node);
1311 return -EEXIST;
1312 }
1313
1314 list_add_tail(&root->root_list, &rc->reloc_roots);
1315 return 0;
1316 }
1317
1318 /*
1319 * helper to delete the 'address of tree root -> reloc tree'
1320 * mapping
1321 */
1322 static void __del_reloc_root(struct btrfs_root *root)
1323 {
1324 struct rb_node *rb_node;
1325 struct mapping_node *node = NULL;
1326 struct reloc_control *rc = root->fs_info->reloc_ctl;
1327
1328 spin_lock(&rc->reloc_root_tree.lock);
1329 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1330 root->node->start);
1331 if (rb_node) {
1332 node = rb_entry(rb_node, struct mapping_node, rb_node);
1333 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1334 }
1335 spin_unlock(&rc->reloc_root_tree.lock);
1336
1337 if (!node)
1338 return;
1339 BUG_ON((struct btrfs_root *)node->data != root);
1340
1341 spin_lock(&root->fs_info->trans_lock);
1342 list_del_init(&root->root_list);
1343 spin_unlock(&root->fs_info->trans_lock);
1344 kfree(node);
1345 }
1346
1347 /*
1348 * helper to update the 'address of tree root -> reloc tree'
1349 * mapping
1350 */
1351 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1352 {
1353 struct rb_node *rb_node;
1354 struct mapping_node *node = NULL;
1355 struct reloc_control *rc = root->fs_info->reloc_ctl;
1356
1357 spin_lock(&rc->reloc_root_tree.lock);
1358 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1359 root->node->start);
1360 if (rb_node) {
1361 node = rb_entry(rb_node, struct mapping_node, rb_node);
1362 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1363 }
1364 spin_unlock(&rc->reloc_root_tree.lock);
1365
1366 if (!node)
1367 return 0;
1368 BUG_ON((struct btrfs_root *)node->data != root);
1369
1370 spin_lock(&rc->reloc_root_tree.lock);
1371 node->bytenr = new_bytenr;
1372 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1373 node->bytenr, &node->rb_node);
1374 spin_unlock(&rc->reloc_root_tree.lock);
1375 if (rb_node)
1376 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1377 return 0;
1378 }
1379
1380 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1381 struct btrfs_root *root, u64 objectid)
1382 {
1383 struct btrfs_root *reloc_root;
1384 struct extent_buffer *eb;
1385 struct btrfs_root_item *root_item;
1386 struct btrfs_key root_key;
1387 u64 last_snap = 0;
1388 int ret;
1389
1390 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1391 BUG_ON(!root_item);
1392
1393 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1394 root_key.type = BTRFS_ROOT_ITEM_KEY;
1395 root_key.offset = objectid;
1396
1397 if (root->root_key.objectid == objectid) {
1398 /* called by btrfs_init_reloc_root */
1399 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1400 BTRFS_TREE_RELOC_OBJECTID);
1401 BUG_ON(ret);
1402
1403 last_snap = btrfs_root_last_snapshot(&root->root_item);
1404 btrfs_set_root_last_snapshot(&root->root_item,
1405 trans->transid - 1);
1406 } else {
1407 /*
1408 * called by btrfs_reloc_post_snapshot_hook.
1409 * the source tree is a reloc tree, all tree blocks
1410 * modified after it was created have RELOC flag
1411 * set in their headers. so it's OK to not update
1412 * the 'last_snapshot'.
1413 */
1414 ret = btrfs_copy_root(trans, root, root->node, &eb,
1415 BTRFS_TREE_RELOC_OBJECTID);
1416 BUG_ON(ret);
1417 }
1418
1419 memcpy(root_item, &root->root_item, sizeof(*root_item));
1420 btrfs_set_root_bytenr(root_item, eb->start);
1421 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1422 btrfs_set_root_generation(root_item, trans->transid);
1423
1424 if (root->root_key.objectid == objectid) {
1425 btrfs_set_root_refs(root_item, 0);
1426 memset(&root_item->drop_progress, 0,
1427 sizeof(struct btrfs_disk_key));
1428 root_item->drop_level = 0;
1429 /*
1430 * abuse rtransid, it is safe because it is impossible to
1431 * receive data into a relocation tree.
1432 */
1433 btrfs_set_root_rtransid(root_item, last_snap);
1434 btrfs_set_root_otransid(root_item, trans->transid);
1435 }
1436
1437 btrfs_tree_unlock(eb);
1438 free_extent_buffer(eb);
1439
1440 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1441 &root_key, root_item);
1442 BUG_ON(ret);
1443 kfree(root_item);
1444
1445 reloc_root = btrfs_read_fs_root(root->fs_info->tree_root, &root_key);
1446 BUG_ON(IS_ERR(reloc_root));
1447 reloc_root->last_trans = trans->transid;
1448 return reloc_root;
1449 }
1450
1451 /*
1452 * create reloc tree for a given fs tree. reloc tree is just a
1453 * snapshot of the fs tree with special root objectid.
1454 */
1455 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1456 struct btrfs_root *root)
1457 {
1458 struct btrfs_root *reloc_root;
1459 struct reloc_control *rc = root->fs_info->reloc_ctl;
1460 struct btrfs_block_rsv *rsv;
1461 int clear_rsv = 0;
1462 int ret;
1463
1464 if (root->reloc_root) {
1465 reloc_root = root->reloc_root;
1466 reloc_root->last_trans = trans->transid;
1467 return 0;
1468 }
1469
1470 if (!rc || !rc->create_reloc_tree ||
1471 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1472 return 0;
1473
1474 if (!trans->reloc_reserved) {
1475 rsv = trans->block_rsv;
1476 trans->block_rsv = rc->block_rsv;
1477 clear_rsv = 1;
1478 }
1479 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1480 if (clear_rsv)
1481 trans->block_rsv = rsv;
1482
1483 ret = __add_reloc_root(reloc_root);
1484 BUG_ON(ret < 0);
1485 root->reloc_root = reloc_root;
1486 return 0;
1487 }
1488
1489 /*
1490 * update root item of reloc tree
1491 */
1492 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1493 struct btrfs_root *root)
1494 {
1495 struct btrfs_root *reloc_root;
1496 struct btrfs_root_item *root_item;
1497 int ret;
1498
1499 if (!root->reloc_root)
1500 goto out;
1501
1502 reloc_root = root->reloc_root;
1503 root_item = &reloc_root->root_item;
1504
1505 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1506 btrfs_root_refs(root_item) == 0) {
1507 root->reloc_root = NULL;
1508 __del_reloc_root(reloc_root);
1509 }
1510
1511 if (reloc_root->commit_root != reloc_root->node) {
1512 btrfs_set_root_node(root_item, reloc_root->node);
1513 free_extent_buffer(reloc_root->commit_root);
1514 reloc_root->commit_root = btrfs_root_node(reloc_root);
1515 }
1516
1517 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1518 &reloc_root->root_key, root_item);
1519 BUG_ON(ret);
1520
1521 out:
1522 return 0;
1523 }
1524
1525 /*
1526 * helper to find first cached inode with inode number >= objectid
1527 * in a subvolume
1528 */
1529 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1530 {
1531 struct rb_node *node;
1532 struct rb_node *prev;
1533 struct btrfs_inode *entry;
1534 struct inode *inode;
1535
1536 spin_lock(&root->inode_lock);
1537 again:
1538 node = root->inode_tree.rb_node;
1539 prev = NULL;
1540 while (node) {
1541 prev = node;
1542 entry = rb_entry(node, struct btrfs_inode, rb_node);
1543
1544 if (objectid < btrfs_ino(&entry->vfs_inode))
1545 node = node->rb_left;
1546 else if (objectid > btrfs_ino(&entry->vfs_inode))
1547 node = node->rb_right;
1548 else
1549 break;
1550 }
1551 if (!node) {
1552 while (prev) {
1553 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1554 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1555 node = prev;
1556 break;
1557 }
1558 prev = rb_next(prev);
1559 }
1560 }
1561 while (node) {
1562 entry = rb_entry(node, struct btrfs_inode, rb_node);
1563 inode = igrab(&entry->vfs_inode);
1564 if (inode) {
1565 spin_unlock(&root->inode_lock);
1566 return inode;
1567 }
1568
1569 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1570 if (cond_resched_lock(&root->inode_lock))
1571 goto again;
1572
1573 node = rb_next(node);
1574 }
1575 spin_unlock(&root->inode_lock);
1576 return NULL;
1577 }
1578
1579 static int in_block_group(u64 bytenr,
1580 struct btrfs_block_group_cache *block_group)
1581 {
1582 if (bytenr >= block_group->key.objectid &&
1583 bytenr < block_group->key.objectid + block_group->key.offset)
1584 return 1;
1585 return 0;
1586 }
1587
1588 /*
1589 * get new location of data
1590 */
1591 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1592 u64 bytenr, u64 num_bytes)
1593 {
1594 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1595 struct btrfs_path *path;
1596 struct btrfs_file_extent_item *fi;
1597 struct extent_buffer *leaf;
1598 int ret;
1599
1600 path = btrfs_alloc_path();
1601 if (!path)
1602 return -ENOMEM;
1603
1604 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1605 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1606 bytenr, 0);
1607 if (ret < 0)
1608 goto out;
1609 if (ret > 0) {
1610 ret = -ENOENT;
1611 goto out;
1612 }
1613
1614 leaf = path->nodes[0];
1615 fi = btrfs_item_ptr(leaf, path->slots[0],
1616 struct btrfs_file_extent_item);
1617
1618 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1619 btrfs_file_extent_compression(leaf, fi) ||
1620 btrfs_file_extent_encryption(leaf, fi) ||
1621 btrfs_file_extent_other_encoding(leaf, fi));
1622
1623 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1624 ret = -EINVAL;
1625 goto out;
1626 }
1627
1628 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1629 ret = 0;
1630 out:
1631 btrfs_free_path(path);
1632 return ret;
1633 }
1634
1635 /*
1636 * update file extent items in the tree leaf to point to
1637 * the new locations.
1638 */
1639 static noinline_for_stack
1640 int replace_file_extents(struct btrfs_trans_handle *trans,
1641 struct reloc_control *rc,
1642 struct btrfs_root *root,
1643 struct extent_buffer *leaf)
1644 {
1645 struct btrfs_key key;
1646 struct btrfs_file_extent_item *fi;
1647 struct inode *inode = NULL;
1648 u64 parent;
1649 u64 bytenr;
1650 u64 new_bytenr = 0;
1651 u64 num_bytes;
1652 u64 end;
1653 u32 nritems;
1654 u32 i;
1655 int ret = 0;
1656 int first = 1;
1657 int dirty = 0;
1658
1659 if (rc->stage != UPDATE_DATA_PTRS)
1660 return 0;
1661
1662 /* reloc trees always use full backref */
1663 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1664 parent = leaf->start;
1665 else
1666 parent = 0;
1667
1668 nritems = btrfs_header_nritems(leaf);
1669 for (i = 0; i < nritems; i++) {
1670 cond_resched();
1671 btrfs_item_key_to_cpu(leaf, &key, i);
1672 if (key.type != BTRFS_EXTENT_DATA_KEY)
1673 continue;
1674 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1675 if (btrfs_file_extent_type(leaf, fi) ==
1676 BTRFS_FILE_EXTENT_INLINE)
1677 continue;
1678 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1679 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1680 if (bytenr == 0)
1681 continue;
1682 if (!in_block_group(bytenr, rc->block_group))
1683 continue;
1684
1685 /*
1686 * if we are modifying block in fs tree, wait for readpage
1687 * to complete and drop the extent cache
1688 */
1689 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1690 if (first) {
1691 inode = find_next_inode(root, key.objectid);
1692 first = 0;
1693 } else if (inode && btrfs_ino(inode) < key.objectid) {
1694 btrfs_add_delayed_iput(inode);
1695 inode = find_next_inode(root, key.objectid);
1696 }
1697 if (inode && btrfs_ino(inode) == key.objectid) {
1698 end = key.offset +
1699 btrfs_file_extent_num_bytes(leaf, fi);
1700 WARN_ON(!IS_ALIGNED(key.offset,
1701 root->sectorsize));
1702 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1703 end--;
1704 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1705 key.offset, end);
1706 if (!ret)
1707 continue;
1708
1709 btrfs_drop_extent_cache(inode, key.offset, end,
1710 1);
1711 unlock_extent(&BTRFS_I(inode)->io_tree,
1712 key.offset, end);
1713 }
1714 }
1715
1716 ret = get_new_location(rc->data_inode, &new_bytenr,
1717 bytenr, num_bytes);
1718 if (ret) {
1719 /*
1720 * Don't have to abort since we've not changed anything
1721 * in the file extent yet.
1722 */
1723 break;
1724 }
1725
1726 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1727 dirty = 1;
1728
1729 key.offset -= btrfs_file_extent_offset(leaf, fi);
1730 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1731 num_bytes, parent,
1732 btrfs_header_owner(leaf),
1733 key.objectid, key.offset);
1734 if (ret) {
1735 btrfs_abort_transaction(trans, ret);
1736 break;
1737 }
1738
1739 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1740 parent, btrfs_header_owner(leaf),
1741 key.objectid, key.offset);
1742 if (ret) {
1743 btrfs_abort_transaction(trans, ret);
1744 break;
1745 }
1746 }
1747 if (dirty)
1748 btrfs_mark_buffer_dirty(leaf);
1749 if (inode)
1750 btrfs_add_delayed_iput(inode);
1751 return ret;
1752 }
1753
1754 static noinline_for_stack
1755 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1756 struct btrfs_path *path, int level)
1757 {
1758 struct btrfs_disk_key key1;
1759 struct btrfs_disk_key key2;
1760 btrfs_node_key(eb, &key1, slot);
1761 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1762 return memcmp(&key1, &key2, sizeof(key1));
1763 }
1764
1765 /*
1766 * try to replace tree blocks in fs tree with the new blocks
1767 * in reloc tree. tree blocks haven't been modified since the
1768 * reloc tree was create can be replaced.
1769 *
1770 * if a block was replaced, level of the block + 1 is returned.
1771 * if no block got replaced, 0 is returned. if there are other
1772 * errors, a negative error number is returned.
1773 */
1774 static noinline_for_stack
1775 int replace_path(struct btrfs_trans_handle *trans,
1776 struct btrfs_root *dest, struct btrfs_root *src,
1777 struct btrfs_path *path, struct btrfs_key *next_key,
1778 int lowest_level, int max_level)
1779 {
1780 struct extent_buffer *eb;
1781 struct extent_buffer *parent;
1782 struct btrfs_key key;
1783 u64 old_bytenr;
1784 u64 new_bytenr;
1785 u64 old_ptr_gen;
1786 u64 new_ptr_gen;
1787 u64 last_snapshot;
1788 u32 blocksize;
1789 int cow = 0;
1790 int level;
1791 int ret;
1792 int slot;
1793
1794 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1795 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1796
1797 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1798 again:
1799 slot = path->slots[lowest_level];
1800 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1801
1802 eb = btrfs_lock_root_node(dest);
1803 btrfs_set_lock_blocking(eb);
1804 level = btrfs_header_level(eb);
1805
1806 if (level < lowest_level) {
1807 btrfs_tree_unlock(eb);
1808 free_extent_buffer(eb);
1809 return 0;
1810 }
1811
1812 if (cow) {
1813 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1814 BUG_ON(ret);
1815 }
1816 btrfs_set_lock_blocking(eb);
1817
1818 if (next_key) {
1819 next_key->objectid = (u64)-1;
1820 next_key->type = (u8)-1;
1821 next_key->offset = (u64)-1;
1822 }
1823
1824 parent = eb;
1825 while (1) {
1826 level = btrfs_header_level(parent);
1827 BUG_ON(level < lowest_level);
1828
1829 ret = btrfs_bin_search(parent, &key, level, &slot);
1830 if (ret && slot > 0)
1831 slot--;
1832
1833 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1834 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1835
1836 old_bytenr = btrfs_node_blockptr(parent, slot);
1837 blocksize = dest->nodesize;
1838 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1839
1840 if (level <= max_level) {
1841 eb = path->nodes[level];
1842 new_bytenr = btrfs_node_blockptr(eb,
1843 path->slots[level]);
1844 new_ptr_gen = btrfs_node_ptr_generation(eb,
1845 path->slots[level]);
1846 } else {
1847 new_bytenr = 0;
1848 new_ptr_gen = 0;
1849 }
1850
1851 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1852 ret = level;
1853 break;
1854 }
1855
1856 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1857 memcmp_node_keys(parent, slot, path, level)) {
1858 if (level <= lowest_level) {
1859 ret = 0;
1860 break;
1861 }
1862
1863 eb = read_tree_block(dest, old_bytenr, old_ptr_gen);
1864 if (IS_ERR(eb)) {
1865 ret = PTR_ERR(eb);
1866 break;
1867 } else if (!extent_buffer_uptodate(eb)) {
1868 ret = -EIO;
1869 free_extent_buffer(eb);
1870 break;
1871 }
1872 btrfs_tree_lock(eb);
1873 if (cow) {
1874 ret = btrfs_cow_block(trans, dest, eb, parent,
1875 slot, &eb);
1876 BUG_ON(ret);
1877 }
1878 btrfs_set_lock_blocking(eb);
1879
1880 btrfs_tree_unlock(parent);
1881 free_extent_buffer(parent);
1882
1883 parent = eb;
1884 continue;
1885 }
1886
1887 if (!cow) {
1888 btrfs_tree_unlock(parent);
1889 free_extent_buffer(parent);
1890 cow = 1;
1891 goto again;
1892 }
1893
1894 btrfs_node_key_to_cpu(path->nodes[level], &key,
1895 path->slots[level]);
1896 btrfs_release_path(path);
1897
1898 path->lowest_level = level;
1899 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1900 path->lowest_level = 0;
1901 BUG_ON(ret);
1902
1903 /*
1904 * swap blocks in fs tree and reloc tree.
1905 */
1906 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1907 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1908 btrfs_mark_buffer_dirty(parent);
1909
1910 btrfs_set_node_blockptr(path->nodes[level],
1911 path->slots[level], old_bytenr);
1912 btrfs_set_node_ptr_generation(path->nodes[level],
1913 path->slots[level], old_ptr_gen);
1914 btrfs_mark_buffer_dirty(path->nodes[level]);
1915
1916 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1917 path->nodes[level]->start,
1918 src->root_key.objectid, level - 1, 0);
1919 BUG_ON(ret);
1920 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1921 0, dest->root_key.objectid, level - 1,
1922 0);
1923 BUG_ON(ret);
1924
1925 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1926 path->nodes[level]->start,
1927 src->root_key.objectid, level - 1, 0);
1928 BUG_ON(ret);
1929
1930 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1931 0, dest->root_key.objectid, level - 1,
1932 0);
1933 BUG_ON(ret);
1934
1935 btrfs_unlock_up_safe(path, 0);
1936
1937 ret = level;
1938 break;
1939 }
1940 btrfs_tree_unlock(parent);
1941 free_extent_buffer(parent);
1942 return ret;
1943 }
1944
1945 /*
1946 * helper to find next relocated block in reloc tree
1947 */
1948 static noinline_for_stack
1949 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1950 int *level)
1951 {
1952 struct extent_buffer *eb;
1953 int i;
1954 u64 last_snapshot;
1955 u32 nritems;
1956
1957 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1958
1959 for (i = 0; i < *level; i++) {
1960 free_extent_buffer(path->nodes[i]);
1961 path->nodes[i] = NULL;
1962 }
1963
1964 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1965 eb = path->nodes[i];
1966 nritems = btrfs_header_nritems(eb);
1967 while (path->slots[i] + 1 < nritems) {
1968 path->slots[i]++;
1969 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1970 last_snapshot)
1971 continue;
1972
1973 *level = i;
1974 return 0;
1975 }
1976 free_extent_buffer(path->nodes[i]);
1977 path->nodes[i] = NULL;
1978 }
1979 return 1;
1980 }
1981
1982 /*
1983 * walk down reloc tree to find relocated block of lowest level
1984 */
1985 static noinline_for_stack
1986 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1987 int *level)
1988 {
1989 struct extent_buffer *eb = NULL;
1990 int i;
1991 u64 bytenr;
1992 u64 ptr_gen = 0;
1993 u64 last_snapshot;
1994 u32 nritems;
1995
1996 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1997
1998 for (i = *level; i > 0; i--) {
1999 eb = path->nodes[i];
2000 nritems = btrfs_header_nritems(eb);
2001 while (path->slots[i] < nritems) {
2002 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2003 if (ptr_gen > last_snapshot)
2004 break;
2005 path->slots[i]++;
2006 }
2007 if (path->slots[i] >= nritems) {
2008 if (i == *level)
2009 break;
2010 *level = i + 1;
2011 return 0;
2012 }
2013 if (i == 1) {
2014 *level = i;
2015 return 0;
2016 }
2017
2018 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2019 eb = read_tree_block(root, bytenr, ptr_gen);
2020 if (IS_ERR(eb)) {
2021 return PTR_ERR(eb);
2022 } else if (!extent_buffer_uptodate(eb)) {
2023 free_extent_buffer(eb);
2024 return -EIO;
2025 }
2026 BUG_ON(btrfs_header_level(eb) != i - 1);
2027 path->nodes[i - 1] = eb;
2028 path->slots[i - 1] = 0;
2029 }
2030 return 1;
2031 }
2032
2033 /*
2034 * invalidate extent cache for file extents whose key in range of
2035 * [min_key, max_key)
2036 */
2037 static int invalidate_extent_cache(struct btrfs_root *root,
2038 struct btrfs_key *min_key,
2039 struct btrfs_key *max_key)
2040 {
2041 struct inode *inode = NULL;
2042 u64 objectid;
2043 u64 start, end;
2044 u64 ino;
2045
2046 objectid = min_key->objectid;
2047 while (1) {
2048 cond_resched();
2049 iput(inode);
2050
2051 if (objectid > max_key->objectid)
2052 break;
2053
2054 inode = find_next_inode(root, objectid);
2055 if (!inode)
2056 break;
2057 ino = btrfs_ino(inode);
2058
2059 if (ino > max_key->objectid) {
2060 iput(inode);
2061 break;
2062 }
2063
2064 objectid = ino + 1;
2065 if (!S_ISREG(inode->i_mode))
2066 continue;
2067
2068 if (unlikely(min_key->objectid == ino)) {
2069 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2070 continue;
2071 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2072 start = 0;
2073 else {
2074 start = min_key->offset;
2075 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
2076 }
2077 } else {
2078 start = 0;
2079 }
2080
2081 if (unlikely(max_key->objectid == ino)) {
2082 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2083 continue;
2084 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2085 end = (u64)-1;
2086 } else {
2087 if (max_key->offset == 0)
2088 continue;
2089 end = max_key->offset;
2090 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
2091 end--;
2092 }
2093 } else {
2094 end = (u64)-1;
2095 }
2096
2097 /* the lock_extent waits for readpage to complete */
2098 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2099 btrfs_drop_extent_cache(inode, start, end, 1);
2100 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2101 }
2102 return 0;
2103 }
2104
2105 static int find_next_key(struct btrfs_path *path, int level,
2106 struct btrfs_key *key)
2107
2108 {
2109 while (level < BTRFS_MAX_LEVEL) {
2110 if (!path->nodes[level])
2111 break;
2112 if (path->slots[level] + 1 <
2113 btrfs_header_nritems(path->nodes[level])) {
2114 btrfs_node_key_to_cpu(path->nodes[level], key,
2115 path->slots[level] + 1);
2116 return 0;
2117 }
2118 level++;
2119 }
2120 return 1;
2121 }
2122
2123 /*
2124 * merge the relocated tree blocks in reloc tree with corresponding
2125 * fs tree.
2126 */
2127 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2128 struct btrfs_root *root)
2129 {
2130 LIST_HEAD(inode_list);
2131 struct btrfs_key key;
2132 struct btrfs_key next_key;
2133 struct btrfs_trans_handle *trans = NULL;
2134 struct btrfs_root *reloc_root;
2135 struct btrfs_root_item *root_item;
2136 struct btrfs_path *path;
2137 struct extent_buffer *leaf;
2138 int level;
2139 int max_level;
2140 int replaced = 0;
2141 int ret;
2142 int err = 0;
2143 u32 min_reserved;
2144
2145 path = btrfs_alloc_path();
2146 if (!path)
2147 return -ENOMEM;
2148 path->reada = READA_FORWARD;
2149
2150 reloc_root = root->reloc_root;
2151 root_item = &reloc_root->root_item;
2152
2153 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2154 level = btrfs_root_level(root_item);
2155 extent_buffer_get(reloc_root->node);
2156 path->nodes[level] = reloc_root->node;
2157 path->slots[level] = 0;
2158 } else {
2159 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2160
2161 level = root_item->drop_level;
2162 BUG_ON(level == 0);
2163 path->lowest_level = level;
2164 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2165 path->lowest_level = 0;
2166 if (ret < 0) {
2167 btrfs_free_path(path);
2168 return ret;
2169 }
2170
2171 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2172 path->slots[level]);
2173 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2174
2175 btrfs_unlock_up_safe(path, 0);
2176 }
2177
2178 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2179 memset(&next_key, 0, sizeof(next_key));
2180
2181 while (1) {
2182 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2183 BTRFS_RESERVE_FLUSH_ALL);
2184 if (ret) {
2185 err = ret;
2186 goto out;
2187 }
2188 trans = btrfs_start_transaction(root, 0);
2189 if (IS_ERR(trans)) {
2190 err = PTR_ERR(trans);
2191 trans = NULL;
2192 goto out;
2193 }
2194 trans->block_rsv = rc->block_rsv;
2195
2196 replaced = 0;
2197 max_level = level;
2198
2199 ret = walk_down_reloc_tree(reloc_root, path, &level);
2200 if (ret < 0) {
2201 err = ret;
2202 goto out;
2203 }
2204 if (ret > 0)
2205 break;
2206
2207 if (!find_next_key(path, level, &key) &&
2208 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2209 ret = 0;
2210 } else {
2211 ret = replace_path(trans, root, reloc_root, path,
2212 &next_key, level, max_level);
2213 }
2214 if (ret < 0) {
2215 err = ret;
2216 goto out;
2217 }
2218
2219 if (ret > 0) {
2220 level = ret;
2221 btrfs_node_key_to_cpu(path->nodes[level], &key,
2222 path->slots[level]);
2223 replaced = 1;
2224 }
2225
2226 ret = walk_up_reloc_tree(reloc_root, path, &level);
2227 if (ret > 0)
2228 break;
2229
2230 BUG_ON(level == 0);
2231 /*
2232 * save the merging progress in the drop_progress.
2233 * this is OK since root refs == 1 in this case.
2234 */
2235 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2236 path->slots[level]);
2237 root_item->drop_level = level;
2238
2239 btrfs_end_transaction_throttle(trans, root);
2240 trans = NULL;
2241
2242 btrfs_btree_balance_dirty(root);
2243
2244 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2245 invalidate_extent_cache(root, &key, &next_key);
2246 }
2247
2248 /*
2249 * handle the case only one block in the fs tree need to be
2250 * relocated and the block is tree root.
2251 */
2252 leaf = btrfs_lock_root_node(root);
2253 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2254 btrfs_tree_unlock(leaf);
2255 free_extent_buffer(leaf);
2256 if (ret < 0)
2257 err = ret;
2258 out:
2259 btrfs_free_path(path);
2260
2261 if (err == 0) {
2262 memset(&root_item->drop_progress, 0,
2263 sizeof(root_item->drop_progress));
2264 root_item->drop_level = 0;
2265 btrfs_set_root_refs(root_item, 0);
2266 btrfs_update_reloc_root(trans, root);
2267 }
2268
2269 if (trans)
2270 btrfs_end_transaction_throttle(trans, root);
2271
2272 btrfs_btree_balance_dirty(root);
2273
2274 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2275 invalidate_extent_cache(root, &key, &next_key);
2276
2277 return err;
2278 }
2279
2280 static noinline_for_stack
2281 int prepare_to_merge(struct reloc_control *rc, int err)
2282 {
2283 struct btrfs_root *root = rc->extent_root;
2284 struct btrfs_root *reloc_root;
2285 struct btrfs_trans_handle *trans;
2286 LIST_HEAD(reloc_roots);
2287 u64 num_bytes = 0;
2288 int ret;
2289
2290 mutex_lock(&root->fs_info->reloc_mutex);
2291 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2292 rc->merging_rsv_size += rc->nodes_relocated * 2;
2293 mutex_unlock(&root->fs_info->reloc_mutex);
2294
2295 again:
2296 if (!err) {
2297 num_bytes = rc->merging_rsv_size;
2298 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2299 BTRFS_RESERVE_FLUSH_ALL);
2300 if (ret)
2301 err = ret;
2302 }
2303
2304 trans = btrfs_join_transaction(rc->extent_root);
2305 if (IS_ERR(trans)) {
2306 if (!err)
2307 btrfs_block_rsv_release(rc->extent_root,
2308 rc->block_rsv, num_bytes);
2309 return PTR_ERR(trans);
2310 }
2311
2312 if (!err) {
2313 if (num_bytes != rc->merging_rsv_size) {
2314 btrfs_end_transaction(trans, rc->extent_root);
2315 btrfs_block_rsv_release(rc->extent_root,
2316 rc->block_rsv, num_bytes);
2317 goto again;
2318 }
2319 }
2320
2321 rc->merge_reloc_tree = 1;
2322
2323 while (!list_empty(&rc->reloc_roots)) {
2324 reloc_root = list_entry(rc->reloc_roots.next,
2325 struct btrfs_root, root_list);
2326 list_del_init(&reloc_root->root_list);
2327
2328 root = read_fs_root(reloc_root->fs_info,
2329 reloc_root->root_key.offset);
2330 BUG_ON(IS_ERR(root));
2331 BUG_ON(root->reloc_root != reloc_root);
2332
2333 /*
2334 * set reference count to 1, so btrfs_recover_relocation
2335 * knows it should resumes merging
2336 */
2337 if (!err)
2338 btrfs_set_root_refs(&reloc_root->root_item, 1);
2339 btrfs_update_reloc_root(trans, root);
2340
2341 list_add(&reloc_root->root_list, &reloc_roots);
2342 }
2343
2344 list_splice(&reloc_roots, &rc->reloc_roots);
2345
2346 if (!err)
2347 btrfs_commit_transaction(trans, rc->extent_root);
2348 else
2349 btrfs_end_transaction(trans, rc->extent_root);
2350 return err;
2351 }
2352
2353 static noinline_for_stack
2354 void free_reloc_roots(struct list_head *list)
2355 {
2356 struct btrfs_root *reloc_root;
2357
2358 while (!list_empty(list)) {
2359 reloc_root = list_entry(list->next, struct btrfs_root,
2360 root_list);
2361 free_extent_buffer(reloc_root->node);
2362 free_extent_buffer(reloc_root->commit_root);
2363 reloc_root->node = NULL;
2364 reloc_root->commit_root = NULL;
2365 __del_reloc_root(reloc_root);
2366 }
2367 }
2368
2369 static noinline_for_stack
2370 void merge_reloc_roots(struct reloc_control *rc)
2371 {
2372 struct btrfs_root *root;
2373 struct btrfs_root *reloc_root;
2374 u64 last_snap;
2375 u64 otransid;
2376 u64 objectid;
2377 LIST_HEAD(reloc_roots);
2378 int found = 0;
2379 int ret = 0;
2380 again:
2381 root = rc->extent_root;
2382
2383 /*
2384 * this serializes us with btrfs_record_root_in_transaction,
2385 * we have to make sure nobody is in the middle of
2386 * adding their roots to the list while we are
2387 * doing this splice
2388 */
2389 mutex_lock(&root->fs_info->reloc_mutex);
2390 list_splice_init(&rc->reloc_roots, &reloc_roots);
2391 mutex_unlock(&root->fs_info->reloc_mutex);
2392
2393 while (!list_empty(&reloc_roots)) {
2394 found = 1;
2395 reloc_root = list_entry(reloc_roots.next,
2396 struct btrfs_root, root_list);
2397
2398 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2399 root = read_fs_root(reloc_root->fs_info,
2400 reloc_root->root_key.offset);
2401 BUG_ON(IS_ERR(root));
2402 BUG_ON(root->reloc_root != reloc_root);
2403
2404 ret = merge_reloc_root(rc, root);
2405 if (ret) {
2406 if (list_empty(&reloc_root->root_list))
2407 list_add_tail(&reloc_root->root_list,
2408 &reloc_roots);
2409 goto out;
2410 }
2411 } else {
2412 list_del_init(&reloc_root->root_list);
2413 }
2414
2415 /*
2416 * we keep the old last snapshot transid in rtranid when we
2417 * created the relocation tree.
2418 */
2419 last_snap = btrfs_root_rtransid(&reloc_root->root_item);
2420 otransid = btrfs_root_otransid(&reloc_root->root_item);
2421 objectid = reloc_root->root_key.offset;
2422
2423 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2424 if (ret < 0) {
2425 if (list_empty(&reloc_root->root_list))
2426 list_add_tail(&reloc_root->root_list,
2427 &reloc_roots);
2428 goto out;
2429 }
2430 }
2431
2432 if (found) {
2433 found = 0;
2434 goto again;
2435 }
2436 out:
2437 if (ret) {
2438 btrfs_handle_fs_error(root->fs_info, ret, NULL);
2439 if (!list_empty(&reloc_roots))
2440 free_reloc_roots(&reloc_roots);
2441
2442 /* new reloc root may be added */
2443 mutex_lock(&root->fs_info->reloc_mutex);
2444 list_splice_init(&rc->reloc_roots, &reloc_roots);
2445 mutex_unlock(&root->fs_info->reloc_mutex);
2446 if (!list_empty(&reloc_roots))
2447 free_reloc_roots(&reloc_roots);
2448 }
2449
2450 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2451 }
2452
2453 static void free_block_list(struct rb_root *blocks)
2454 {
2455 struct tree_block *block;
2456 struct rb_node *rb_node;
2457 while ((rb_node = rb_first(blocks))) {
2458 block = rb_entry(rb_node, struct tree_block, rb_node);
2459 rb_erase(rb_node, blocks);
2460 kfree(block);
2461 }
2462 }
2463
2464 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2465 struct btrfs_root *reloc_root)
2466 {
2467 struct btrfs_root *root;
2468
2469 if (reloc_root->last_trans == trans->transid)
2470 return 0;
2471
2472 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2473 BUG_ON(IS_ERR(root));
2474 BUG_ON(root->reloc_root != reloc_root);
2475
2476 return btrfs_record_root_in_trans(trans, root);
2477 }
2478
2479 static noinline_for_stack
2480 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2481 struct reloc_control *rc,
2482 struct backref_node *node,
2483 struct backref_edge *edges[])
2484 {
2485 struct backref_node *next;
2486 struct btrfs_root *root;
2487 int index = 0;
2488
2489 next = node;
2490 while (1) {
2491 cond_resched();
2492 next = walk_up_backref(next, edges, &index);
2493 root = next->root;
2494 BUG_ON(!root);
2495 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2496
2497 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2498 record_reloc_root_in_trans(trans, root);
2499 break;
2500 }
2501
2502 btrfs_record_root_in_trans(trans, root);
2503 root = root->reloc_root;
2504
2505 if (next->new_bytenr != root->node->start) {
2506 BUG_ON(next->new_bytenr);
2507 BUG_ON(!list_empty(&next->list));
2508 next->new_bytenr = root->node->start;
2509 next->root = root;
2510 list_add_tail(&next->list,
2511 &rc->backref_cache.changed);
2512 __mark_block_processed(rc, next);
2513 break;
2514 }
2515
2516 WARN_ON(1);
2517 root = NULL;
2518 next = walk_down_backref(edges, &index);
2519 if (!next || next->level <= node->level)
2520 break;
2521 }
2522 if (!root)
2523 return NULL;
2524
2525 next = node;
2526 /* setup backref node path for btrfs_reloc_cow_block */
2527 while (1) {
2528 rc->backref_cache.path[next->level] = next;
2529 if (--index < 0)
2530 break;
2531 next = edges[index]->node[UPPER];
2532 }
2533 return root;
2534 }
2535
2536 /*
2537 * select a tree root for relocation. return NULL if the block
2538 * is reference counted. we should use do_relocation() in this
2539 * case. return a tree root pointer if the block isn't reference
2540 * counted. return -ENOENT if the block is root of reloc tree.
2541 */
2542 static noinline_for_stack
2543 struct btrfs_root *select_one_root(struct backref_node *node)
2544 {
2545 struct backref_node *next;
2546 struct btrfs_root *root;
2547 struct btrfs_root *fs_root = NULL;
2548 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2549 int index = 0;
2550
2551 next = node;
2552 while (1) {
2553 cond_resched();
2554 next = walk_up_backref(next, edges, &index);
2555 root = next->root;
2556 BUG_ON(!root);
2557
2558 /* no other choice for non-references counted tree */
2559 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2560 return root;
2561
2562 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2563 fs_root = root;
2564
2565 if (next != node)
2566 return NULL;
2567
2568 next = walk_down_backref(edges, &index);
2569 if (!next || next->level <= node->level)
2570 break;
2571 }
2572
2573 if (!fs_root)
2574 return ERR_PTR(-ENOENT);
2575 return fs_root;
2576 }
2577
2578 static noinline_for_stack
2579 u64 calcu_metadata_size(struct reloc_control *rc,
2580 struct backref_node *node, int reserve)
2581 {
2582 struct backref_node *next = node;
2583 struct backref_edge *edge;
2584 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2585 u64 num_bytes = 0;
2586 int index = 0;
2587
2588 BUG_ON(reserve && node->processed);
2589
2590 while (next) {
2591 cond_resched();
2592 while (1) {
2593 if (next->processed && (reserve || next != node))
2594 break;
2595
2596 num_bytes += rc->extent_root->nodesize;
2597
2598 if (list_empty(&next->upper))
2599 break;
2600
2601 edge = list_entry(next->upper.next,
2602 struct backref_edge, list[LOWER]);
2603 edges[index++] = edge;
2604 next = edge->node[UPPER];
2605 }
2606 next = walk_down_backref(edges, &index);
2607 }
2608 return num_bytes;
2609 }
2610
2611 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2612 struct reloc_control *rc,
2613 struct backref_node *node)
2614 {
2615 struct btrfs_root *root = rc->extent_root;
2616 u64 num_bytes;
2617 int ret;
2618 u64 tmp;
2619
2620 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2621
2622 trans->block_rsv = rc->block_rsv;
2623 rc->reserved_bytes += num_bytes;
2624
2625 /*
2626 * We are under a transaction here so we can only do limited flushing.
2627 * If we get an enospc just kick back -EAGAIN so we know to drop the
2628 * transaction and try to refill when we can flush all the things.
2629 */
2630 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2631 BTRFS_RESERVE_FLUSH_LIMIT);
2632 if (ret) {
2633 tmp = rc->extent_root->nodesize * RELOCATION_RESERVED_NODES;
2634 while (tmp <= rc->reserved_bytes)
2635 tmp <<= 1;
2636 /*
2637 * only one thread can access block_rsv at this point,
2638 * so we don't need hold lock to protect block_rsv.
2639 * we expand more reservation size here to allow enough
2640 * space for relocation and we will return eailer in
2641 * enospc case.
2642 */
2643 rc->block_rsv->size = tmp + rc->extent_root->nodesize *
2644 RELOCATION_RESERVED_NODES;
2645 return -EAGAIN;
2646 }
2647
2648 return 0;
2649 }
2650
2651 /*
2652 * relocate a block tree, and then update pointers in upper level
2653 * blocks that reference the block to point to the new location.
2654 *
2655 * if called by link_to_upper, the block has already been relocated.
2656 * in that case this function just updates pointers.
2657 */
2658 static int do_relocation(struct btrfs_trans_handle *trans,
2659 struct reloc_control *rc,
2660 struct backref_node *node,
2661 struct btrfs_key *key,
2662 struct btrfs_path *path, int lowest)
2663 {
2664 struct backref_node *upper;
2665 struct backref_edge *edge;
2666 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2667 struct btrfs_root *root;
2668 struct extent_buffer *eb;
2669 u32 blocksize;
2670 u64 bytenr;
2671 u64 generation;
2672 int slot;
2673 int ret;
2674 int err = 0;
2675
2676 BUG_ON(lowest && node->eb);
2677
2678 path->lowest_level = node->level + 1;
2679 rc->backref_cache.path[node->level] = node;
2680 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2681 cond_resched();
2682
2683 upper = edge->node[UPPER];
2684 root = select_reloc_root(trans, rc, upper, edges);
2685 BUG_ON(!root);
2686
2687 if (upper->eb && !upper->locked) {
2688 if (!lowest) {
2689 ret = btrfs_bin_search(upper->eb, key,
2690 upper->level, &slot);
2691 BUG_ON(ret);
2692 bytenr = btrfs_node_blockptr(upper->eb, slot);
2693 if (node->eb->start == bytenr)
2694 goto next;
2695 }
2696 drop_node_buffer(upper);
2697 }
2698
2699 if (!upper->eb) {
2700 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2701 if (ret) {
2702 if (ret < 0)
2703 err = ret;
2704 else
2705 err = -ENOENT;
2706
2707 btrfs_release_path(path);
2708 break;
2709 }
2710
2711 if (!upper->eb) {
2712 upper->eb = path->nodes[upper->level];
2713 path->nodes[upper->level] = NULL;
2714 } else {
2715 BUG_ON(upper->eb != path->nodes[upper->level]);
2716 }
2717
2718 upper->locked = 1;
2719 path->locks[upper->level] = 0;
2720
2721 slot = path->slots[upper->level];
2722 btrfs_release_path(path);
2723 } else {
2724 ret = btrfs_bin_search(upper->eb, key, upper->level,
2725 &slot);
2726 BUG_ON(ret);
2727 }
2728
2729 bytenr = btrfs_node_blockptr(upper->eb, slot);
2730 if (lowest) {
2731 BUG_ON(bytenr != node->bytenr);
2732 } else {
2733 if (node->eb->start == bytenr)
2734 goto next;
2735 }
2736
2737 blocksize = root->nodesize;
2738 generation = btrfs_node_ptr_generation(upper->eb, slot);
2739 eb = read_tree_block(root, bytenr, generation);
2740 if (IS_ERR(eb)) {
2741 err = PTR_ERR(eb);
2742 goto next;
2743 } else if (!extent_buffer_uptodate(eb)) {
2744 free_extent_buffer(eb);
2745 err = -EIO;
2746 goto next;
2747 }
2748 btrfs_tree_lock(eb);
2749 btrfs_set_lock_blocking(eb);
2750
2751 if (!node->eb) {
2752 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2753 slot, &eb);
2754 btrfs_tree_unlock(eb);
2755 free_extent_buffer(eb);
2756 if (ret < 0) {
2757 err = ret;
2758 goto next;
2759 }
2760 BUG_ON(node->eb != eb);
2761 } else {
2762 btrfs_set_node_blockptr(upper->eb, slot,
2763 node->eb->start);
2764 btrfs_set_node_ptr_generation(upper->eb, slot,
2765 trans->transid);
2766 btrfs_mark_buffer_dirty(upper->eb);
2767
2768 ret = btrfs_inc_extent_ref(trans, root,
2769 node->eb->start, blocksize,
2770 upper->eb->start,
2771 btrfs_header_owner(upper->eb),
2772 node->level, 0);
2773 BUG_ON(ret);
2774
2775 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2776 BUG_ON(ret);
2777 }
2778 next:
2779 if (!upper->pending)
2780 drop_node_buffer(upper);
2781 else
2782 unlock_node_buffer(upper);
2783 if (err)
2784 break;
2785 }
2786
2787 if (!err && node->pending) {
2788 drop_node_buffer(node);
2789 list_move_tail(&node->list, &rc->backref_cache.changed);
2790 node->pending = 0;
2791 }
2792
2793 path->lowest_level = 0;
2794 BUG_ON(err == -ENOSPC);
2795 return err;
2796 }
2797
2798 static int link_to_upper(struct btrfs_trans_handle *trans,
2799 struct reloc_control *rc,
2800 struct backref_node *node,
2801 struct btrfs_path *path)
2802 {
2803 struct btrfs_key key;
2804
2805 btrfs_node_key_to_cpu(node->eb, &key, 0);
2806 return do_relocation(trans, rc, node, &key, path, 0);
2807 }
2808
2809 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2810 struct reloc_control *rc,
2811 struct btrfs_path *path, int err)
2812 {
2813 LIST_HEAD(list);
2814 struct backref_cache *cache = &rc->backref_cache;
2815 struct backref_node *node;
2816 int level;
2817 int ret;
2818
2819 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2820 while (!list_empty(&cache->pending[level])) {
2821 node = list_entry(cache->pending[level].next,
2822 struct backref_node, list);
2823 list_move_tail(&node->list, &list);
2824 BUG_ON(!node->pending);
2825
2826 if (!err) {
2827 ret = link_to_upper(trans, rc, node, path);
2828 if (ret < 0)
2829 err = ret;
2830 }
2831 }
2832 list_splice_init(&list, &cache->pending[level]);
2833 }
2834 return err;
2835 }
2836
2837 static void mark_block_processed(struct reloc_control *rc,
2838 u64 bytenr, u32 blocksize)
2839 {
2840 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2841 EXTENT_DIRTY);
2842 }
2843
2844 static void __mark_block_processed(struct reloc_control *rc,
2845 struct backref_node *node)
2846 {
2847 u32 blocksize;
2848 if (node->level == 0 ||
2849 in_block_group(node->bytenr, rc->block_group)) {
2850 blocksize = rc->extent_root->nodesize;
2851 mark_block_processed(rc, node->bytenr, blocksize);
2852 }
2853 node->processed = 1;
2854 }
2855
2856 /*
2857 * mark a block and all blocks directly/indirectly reference the block
2858 * as processed.
2859 */
2860 static void update_processed_blocks(struct reloc_control *rc,
2861 struct backref_node *node)
2862 {
2863 struct backref_node *next = node;
2864 struct backref_edge *edge;
2865 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2866 int index = 0;
2867
2868 while (next) {
2869 cond_resched();
2870 while (1) {
2871 if (next->processed)
2872 break;
2873
2874 __mark_block_processed(rc, next);
2875
2876 if (list_empty(&next->upper))
2877 break;
2878
2879 edge = list_entry(next->upper.next,
2880 struct backref_edge, list[LOWER]);
2881 edges[index++] = edge;
2882 next = edge->node[UPPER];
2883 }
2884 next = walk_down_backref(edges, &index);
2885 }
2886 }
2887
2888 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2889 {
2890 u32 blocksize = rc->extent_root->nodesize;
2891
2892 if (test_range_bit(&rc->processed_blocks, bytenr,
2893 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2894 return 1;
2895 return 0;
2896 }
2897
2898 static int get_tree_block_key(struct reloc_control *rc,
2899 struct tree_block *block)
2900 {
2901 struct extent_buffer *eb;
2902
2903 BUG_ON(block->key_ready);
2904 eb = read_tree_block(rc->extent_root, block->bytenr,
2905 block->key.offset);
2906 if (IS_ERR(eb)) {
2907 return PTR_ERR(eb);
2908 } else if (!extent_buffer_uptodate(eb)) {
2909 free_extent_buffer(eb);
2910 return -EIO;
2911 }
2912 WARN_ON(btrfs_header_level(eb) != block->level);
2913 if (block->level == 0)
2914 btrfs_item_key_to_cpu(eb, &block->key, 0);
2915 else
2916 btrfs_node_key_to_cpu(eb, &block->key, 0);
2917 free_extent_buffer(eb);
2918 block->key_ready = 1;
2919 return 0;
2920 }
2921
2922 /*
2923 * helper function to relocate a tree block
2924 */
2925 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2926 struct reloc_control *rc,
2927 struct backref_node *node,
2928 struct btrfs_key *key,
2929 struct btrfs_path *path)
2930 {
2931 struct btrfs_root *root;
2932 int ret = 0;
2933
2934 if (!node)
2935 return 0;
2936
2937 BUG_ON(node->processed);
2938 root = select_one_root(node);
2939 if (root == ERR_PTR(-ENOENT)) {
2940 update_processed_blocks(rc, node);
2941 goto out;
2942 }
2943
2944 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2945 ret = reserve_metadata_space(trans, rc, node);
2946 if (ret)
2947 goto out;
2948 }
2949
2950 if (root) {
2951 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2952 BUG_ON(node->new_bytenr);
2953 BUG_ON(!list_empty(&node->list));
2954 btrfs_record_root_in_trans(trans, root);
2955 root = root->reloc_root;
2956 node->new_bytenr = root->node->start;
2957 node->root = root;
2958 list_add_tail(&node->list, &rc->backref_cache.changed);
2959 } else {
2960 path->lowest_level = node->level;
2961 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2962 btrfs_release_path(path);
2963 if (ret > 0)
2964 ret = 0;
2965 }
2966 if (!ret)
2967 update_processed_blocks(rc, node);
2968 } else {
2969 ret = do_relocation(trans, rc, node, key, path, 1);
2970 }
2971 out:
2972 if (ret || node->level == 0 || node->cowonly)
2973 remove_backref_node(&rc->backref_cache, node);
2974 return ret;
2975 }
2976
2977 /*
2978 * relocate a list of blocks
2979 */
2980 static noinline_for_stack
2981 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2982 struct reloc_control *rc, struct rb_root *blocks)
2983 {
2984 struct backref_node *node;
2985 struct btrfs_path *path;
2986 struct tree_block *block;
2987 struct rb_node *rb_node;
2988 int ret;
2989 int err = 0;
2990
2991 path = btrfs_alloc_path();
2992 if (!path) {
2993 err = -ENOMEM;
2994 goto out_free_blocks;
2995 }
2996
2997 rb_node = rb_first(blocks);
2998 while (rb_node) {
2999 block = rb_entry(rb_node, struct tree_block, rb_node);
3000 if (!block->key_ready)
3001 readahead_tree_block(rc->extent_root, block->bytenr);
3002 rb_node = rb_next(rb_node);
3003 }
3004
3005 rb_node = rb_first(blocks);
3006 while (rb_node) {
3007 block = rb_entry(rb_node, struct tree_block, rb_node);
3008 if (!block->key_ready) {
3009 err = get_tree_block_key(rc, block);
3010 if (err)
3011 goto out_free_path;
3012 }
3013 rb_node = rb_next(rb_node);
3014 }
3015
3016 rb_node = rb_first(blocks);
3017 while (rb_node) {
3018 block = rb_entry(rb_node, struct tree_block, rb_node);
3019
3020 node = build_backref_tree(rc, &block->key,
3021 block->level, block->bytenr);
3022 if (IS_ERR(node)) {
3023 err = PTR_ERR(node);
3024 goto out;
3025 }
3026
3027 ret = relocate_tree_block(trans, rc, node, &block->key,
3028 path);
3029 if (ret < 0) {
3030 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3031 err = ret;
3032 goto out;
3033 }
3034 rb_node = rb_next(rb_node);
3035 }
3036 out:
3037 err = finish_pending_nodes(trans, rc, path, err);
3038
3039 out_free_path:
3040 btrfs_free_path(path);
3041 out_free_blocks:
3042 free_block_list(blocks);
3043 return err;
3044 }
3045
3046 static noinline_for_stack
3047 int prealloc_file_extent_cluster(struct inode *inode,
3048 struct file_extent_cluster *cluster)
3049 {
3050 u64 alloc_hint = 0;
3051 u64 start;
3052 u64 end;
3053 u64 offset = BTRFS_I(inode)->index_cnt;
3054 u64 num_bytes;
3055 int nr = 0;
3056 int ret = 0;
3057 u64 prealloc_start = cluster->start - offset;
3058 u64 prealloc_end = cluster->end - offset;
3059 u64 cur_offset;
3060
3061 BUG_ON(cluster->start != cluster->boundary[0]);
3062 inode_lock(inode);
3063
3064 ret = btrfs_check_data_free_space(inode, prealloc_start,
3065 prealloc_end + 1 - prealloc_start);
3066 if (ret)
3067 goto out;
3068
3069 cur_offset = prealloc_start;
3070 while (nr < cluster->nr) {
3071 start = cluster->boundary[nr] - offset;
3072 if (nr + 1 < cluster->nr)
3073 end = cluster->boundary[nr + 1] - 1 - offset;
3074 else
3075 end = cluster->end - offset;
3076
3077 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3078 num_bytes = end + 1 - start;
3079 if (cur_offset < start)
3080 btrfs_free_reserved_data_space(inode, cur_offset,
3081 start - cur_offset);
3082 ret = btrfs_prealloc_file_range(inode, 0, start,
3083 num_bytes, num_bytes,
3084 end + 1, &alloc_hint);
3085 cur_offset = end + 1;
3086 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3087 if (ret)
3088 break;
3089 nr++;
3090 }
3091 if (cur_offset < prealloc_end)
3092 btrfs_free_reserved_data_space(inode, cur_offset,
3093 prealloc_end + 1 - cur_offset);
3094 out:
3095 inode_unlock(inode);
3096 return ret;
3097 }
3098
3099 static noinline_for_stack
3100 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3101 u64 block_start)
3102 {
3103 struct btrfs_root *root = BTRFS_I(inode)->root;
3104 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3105 struct extent_map *em;
3106 int ret = 0;
3107
3108 em = alloc_extent_map();
3109 if (!em)
3110 return -ENOMEM;
3111
3112 em->start = start;
3113 em->len = end + 1 - start;
3114 em->block_len = em->len;
3115 em->block_start = block_start;
3116 em->bdev = root->fs_info->fs_devices->latest_bdev;
3117 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3118
3119 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3120 while (1) {
3121 write_lock(&em_tree->lock);
3122 ret = add_extent_mapping(em_tree, em, 0);
3123 write_unlock(&em_tree->lock);
3124 if (ret != -EEXIST) {
3125 free_extent_map(em);
3126 break;
3127 }
3128 btrfs_drop_extent_cache(inode, start, end, 0);
3129 }
3130 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3131 return ret;
3132 }
3133
3134 static int relocate_file_extent_cluster(struct inode *inode,
3135 struct file_extent_cluster *cluster)
3136 {
3137 u64 page_start;
3138 u64 page_end;
3139 u64 offset = BTRFS_I(inode)->index_cnt;
3140 unsigned long index;
3141 unsigned long last_index;
3142 struct page *page;
3143 struct file_ra_state *ra;
3144 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3145 int nr = 0;
3146 int ret = 0;
3147
3148 if (!cluster->nr)
3149 return 0;
3150
3151 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3152 if (!ra)
3153 return -ENOMEM;
3154
3155 ret = prealloc_file_extent_cluster(inode, cluster);
3156 if (ret)
3157 goto out;
3158
3159 file_ra_state_init(ra, inode->i_mapping);
3160
3161 ret = setup_extent_mapping(inode, cluster->start - offset,
3162 cluster->end - offset, cluster->start);
3163 if (ret)
3164 goto out;
3165
3166 index = (cluster->start - offset) >> PAGE_SHIFT;
3167 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3168 while (index <= last_index) {
3169 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_SIZE);
3170 if (ret)
3171 goto out;
3172
3173 page = find_lock_page(inode->i_mapping, index);
3174 if (!page) {
3175 page_cache_sync_readahead(inode->i_mapping,
3176 ra, NULL, index,
3177 last_index + 1 - index);
3178 page = find_or_create_page(inode->i_mapping, index,
3179 mask);
3180 if (!page) {
3181 btrfs_delalloc_release_metadata(inode,
3182 PAGE_SIZE);
3183 ret = -ENOMEM;
3184 goto out;
3185 }
3186 }
3187
3188 if (PageReadahead(page)) {
3189 page_cache_async_readahead(inode->i_mapping,
3190 ra, NULL, page, index,
3191 last_index + 1 - index);
3192 }
3193
3194 if (!PageUptodate(page)) {
3195 btrfs_readpage(NULL, page);
3196 lock_page(page);
3197 if (!PageUptodate(page)) {
3198 unlock_page(page);
3199 put_page(page);
3200 btrfs_delalloc_release_metadata(inode,
3201 PAGE_SIZE);
3202 ret = -EIO;
3203 goto out;
3204 }
3205 }
3206
3207 page_start = page_offset(page);
3208 page_end = page_start + PAGE_SIZE - 1;
3209
3210 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3211
3212 set_page_extent_mapped(page);
3213
3214 if (nr < cluster->nr &&
3215 page_start + offset == cluster->boundary[nr]) {
3216 set_extent_bits(&BTRFS_I(inode)->io_tree,
3217 page_start, page_end,
3218 EXTENT_BOUNDARY);
3219 nr++;
3220 }
3221
3222 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL, 0);
3223 set_page_dirty(page);
3224
3225 unlock_extent(&BTRFS_I(inode)->io_tree,
3226 page_start, page_end);
3227 unlock_page(page);
3228 put_page(page);
3229
3230 index++;
3231 balance_dirty_pages_ratelimited(inode->i_mapping);
3232 btrfs_throttle(BTRFS_I(inode)->root);
3233 }
3234 WARN_ON(nr != cluster->nr);
3235 out:
3236 kfree(ra);
3237 return ret;
3238 }
3239
3240 static noinline_for_stack
3241 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3242 struct file_extent_cluster *cluster)
3243 {
3244 int ret;
3245
3246 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3247 ret = relocate_file_extent_cluster(inode, cluster);
3248 if (ret)
3249 return ret;
3250 cluster->nr = 0;
3251 }
3252
3253 if (!cluster->nr)
3254 cluster->start = extent_key->objectid;
3255 else
3256 BUG_ON(cluster->nr >= MAX_EXTENTS);
3257 cluster->end = extent_key->objectid + extent_key->offset - 1;
3258 cluster->boundary[cluster->nr] = extent_key->objectid;
3259 cluster->nr++;
3260
3261 if (cluster->nr >= MAX_EXTENTS) {
3262 ret = relocate_file_extent_cluster(inode, cluster);
3263 if (ret)
3264 return ret;
3265 cluster->nr = 0;
3266 }
3267 return 0;
3268 }
3269
3270 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3271 static int get_ref_objectid_v0(struct reloc_control *rc,
3272 struct btrfs_path *path,
3273 struct btrfs_key *extent_key,
3274 u64 *ref_objectid, int *path_change)
3275 {
3276 struct btrfs_key key;
3277 struct extent_buffer *leaf;
3278 struct btrfs_extent_ref_v0 *ref0;
3279 int ret;
3280 int slot;
3281
3282 leaf = path->nodes[0];
3283 slot = path->slots[0];
3284 while (1) {
3285 if (slot >= btrfs_header_nritems(leaf)) {
3286 ret = btrfs_next_leaf(rc->extent_root, path);
3287 if (ret < 0)
3288 return ret;
3289 BUG_ON(ret > 0);
3290 leaf = path->nodes[0];
3291 slot = path->slots[0];
3292 if (path_change)
3293 *path_change = 1;
3294 }
3295 btrfs_item_key_to_cpu(leaf, &key, slot);
3296 if (key.objectid != extent_key->objectid)
3297 return -ENOENT;
3298
3299 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3300 slot++;
3301 continue;
3302 }
3303 ref0 = btrfs_item_ptr(leaf, slot,
3304 struct btrfs_extent_ref_v0);
3305 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3306 break;
3307 }
3308 return 0;
3309 }
3310 #endif
3311
3312 /*
3313 * helper to add a tree block to the list.
3314 * the major work is getting the generation and level of the block
3315 */
3316 static int add_tree_block(struct reloc_control *rc,
3317 struct btrfs_key *extent_key,
3318 struct btrfs_path *path,
3319 struct rb_root *blocks)
3320 {
3321 struct extent_buffer *eb;
3322 struct btrfs_extent_item *ei;
3323 struct btrfs_tree_block_info *bi;
3324 struct tree_block *block;
3325 struct rb_node *rb_node;
3326 u32 item_size;
3327 int level = -1;
3328 u64 generation;
3329
3330 eb = path->nodes[0];
3331 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3332
3333 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3334 item_size >= sizeof(*ei) + sizeof(*bi)) {
3335 ei = btrfs_item_ptr(eb, path->slots[0],
3336 struct btrfs_extent_item);
3337 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3338 bi = (struct btrfs_tree_block_info *)(ei + 1);
3339 level = btrfs_tree_block_level(eb, bi);
3340 } else {
3341 level = (int)extent_key->offset;
3342 }
3343 generation = btrfs_extent_generation(eb, ei);
3344 } else {
3345 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3346 u64 ref_owner;
3347 int ret;
3348
3349 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3350 ret = get_ref_objectid_v0(rc, path, extent_key,
3351 &ref_owner, NULL);
3352 if (ret < 0)
3353 return ret;
3354 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3355 level = (int)ref_owner;
3356 /* FIXME: get real generation */
3357 generation = 0;
3358 #else
3359 BUG();
3360 #endif
3361 }
3362
3363 btrfs_release_path(path);
3364
3365 BUG_ON(level == -1);
3366
3367 block = kmalloc(sizeof(*block), GFP_NOFS);
3368 if (!block)
3369 return -ENOMEM;
3370
3371 block->bytenr = extent_key->objectid;
3372 block->key.objectid = rc->extent_root->nodesize;
3373 block->key.offset = generation;
3374 block->level = level;
3375 block->key_ready = 0;
3376
3377 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3378 if (rb_node)
3379 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3380
3381 return 0;
3382 }
3383
3384 /*
3385 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3386 */
3387 static int __add_tree_block(struct reloc_control *rc,
3388 u64 bytenr, u32 blocksize,
3389 struct rb_root *blocks)
3390 {
3391 struct btrfs_path *path;
3392 struct btrfs_key key;
3393 int ret;
3394 bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info,
3395 SKINNY_METADATA);
3396
3397 if (tree_block_processed(bytenr, rc))
3398 return 0;
3399
3400 if (tree_search(blocks, bytenr))
3401 return 0;
3402
3403 path = btrfs_alloc_path();
3404 if (!path)
3405 return -ENOMEM;
3406 again:
3407 key.objectid = bytenr;
3408 if (skinny) {
3409 key.type = BTRFS_METADATA_ITEM_KEY;
3410 key.offset = (u64)-1;
3411 } else {
3412 key.type = BTRFS_EXTENT_ITEM_KEY;
3413 key.offset = blocksize;
3414 }
3415
3416 path->search_commit_root = 1;
3417 path->skip_locking = 1;
3418 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3419 if (ret < 0)
3420 goto out;
3421
3422 if (ret > 0 && skinny) {
3423 if (path->slots[0]) {
3424 path->slots[0]--;
3425 btrfs_item_key_to_cpu(path->nodes[0], &key,
3426 path->slots[0]);
3427 if (key.objectid == bytenr &&
3428 (key.type == BTRFS_METADATA_ITEM_KEY ||
3429 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3430 key.offset == blocksize)))
3431 ret = 0;
3432 }
3433
3434 if (ret) {
3435 skinny = false;
3436 btrfs_release_path(path);
3437 goto again;
3438 }
3439 }
3440 BUG_ON(ret);
3441
3442 ret = add_tree_block(rc, &key, path, blocks);
3443 out:
3444 btrfs_free_path(path);
3445 return ret;
3446 }
3447
3448 /*
3449 * helper to check if the block use full backrefs for pointers in it
3450 */
3451 static int block_use_full_backref(struct reloc_control *rc,
3452 struct extent_buffer *eb)
3453 {
3454 u64 flags;
3455 int ret;
3456
3457 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3458 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3459 return 1;
3460
3461 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3462 eb->start, btrfs_header_level(eb), 1,
3463 NULL, &flags);
3464 BUG_ON(ret);
3465
3466 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3467 ret = 1;
3468 else
3469 ret = 0;
3470 return ret;
3471 }
3472
3473 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3474 struct btrfs_block_group_cache *block_group,
3475 struct inode *inode,
3476 u64 ino)
3477 {
3478 struct btrfs_key key;
3479 struct btrfs_root *root = fs_info->tree_root;
3480 struct btrfs_trans_handle *trans;
3481 int ret = 0;
3482
3483 if (inode)
3484 goto truncate;
3485
3486 key.objectid = ino;
3487 key.type = BTRFS_INODE_ITEM_KEY;
3488 key.offset = 0;
3489
3490 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3491 if (IS_ERR(inode) || is_bad_inode(inode)) {
3492 if (!IS_ERR(inode))
3493 iput(inode);
3494 return -ENOENT;
3495 }
3496
3497 truncate:
3498 ret = btrfs_check_trunc_cache_free_space(root,
3499 &fs_info->global_block_rsv);
3500 if (ret)
3501 goto out;
3502
3503 trans = btrfs_join_transaction(root);
3504 if (IS_ERR(trans)) {
3505 ret = PTR_ERR(trans);
3506 goto out;
3507 }
3508
3509 ret = btrfs_truncate_free_space_cache(root, trans, block_group, inode);
3510
3511 btrfs_end_transaction(trans, root);
3512 btrfs_btree_balance_dirty(root);
3513 out:
3514 iput(inode);
3515 return ret;
3516 }
3517
3518 /*
3519 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3520 * this function scans fs tree to find blocks reference the data extent
3521 */
3522 static int find_data_references(struct reloc_control *rc,
3523 struct btrfs_key *extent_key,
3524 struct extent_buffer *leaf,
3525 struct btrfs_extent_data_ref *ref,
3526 struct rb_root *blocks)
3527 {
3528 struct btrfs_path *path;
3529 struct tree_block *block;
3530 struct btrfs_root *root;
3531 struct btrfs_file_extent_item *fi;
3532 struct rb_node *rb_node;
3533 struct btrfs_key key;
3534 u64 ref_root;
3535 u64 ref_objectid;
3536 u64 ref_offset;
3537 u32 ref_count;
3538 u32 nritems;
3539 int err = 0;
3540 int added = 0;
3541 int counted;
3542 int ret;
3543
3544 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3545 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3546 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3547 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3548
3549 /*
3550 * This is an extent belonging to the free space cache, lets just delete
3551 * it and redo the search.
3552 */
3553 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3554 ret = delete_block_group_cache(rc->extent_root->fs_info,
3555 rc->block_group,
3556 NULL, ref_objectid);
3557 if (ret != -ENOENT)
3558 return ret;
3559 ret = 0;
3560 }
3561
3562 path = btrfs_alloc_path();
3563 if (!path)
3564 return -ENOMEM;
3565 path->reada = READA_FORWARD;
3566
3567 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3568 if (IS_ERR(root)) {
3569 err = PTR_ERR(root);
3570 goto out;
3571 }
3572
3573 key.objectid = ref_objectid;
3574 key.type = BTRFS_EXTENT_DATA_KEY;
3575 if (ref_offset > ((u64)-1 << 32))
3576 key.offset = 0;
3577 else
3578 key.offset = ref_offset;
3579
3580 path->search_commit_root = 1;
3581 path->skip_locking = 1;
3582 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3583 if (ret < 0) {
3584 err = ret;
3585 goto out;
3586 }
3587
3588 leaf = path->nodes[0];
3589 nritems = btrfs_header_nritems(leaf);
3590 /*
3591 * the references in tree blocks that use full backrefs
3592 * are not counted in
3593 */
3594 if (block_use_full_backref(rc, leaf))
3595 counted = 0;
3596 else
3597 counted = 1;
3598 rb_node = tree_search(blocks, leaf->start);
3599 if (rb_node) {
3600 if (counted)
3601 added = 1;
3602 else
3603 path->slots[0] = nritems;
3604 }
3605
3606 while (ref_count > 0) {
3607 while (path->slots[0] >= nritems) {
3608 ret = btrfs_next_leaf(root, path);
3609 if (ret < 0) {
3610 err = ret;
3611 goto out;
3612 }
3613 if (WARN_ON(ret > 0))
3614 goto out;
3615
3616 leaf = path->nodes[0];
3617 nritems = btrfs_header_nritems(leaf);
3618 added = 0;
3619
3620 if (block_use_full_backref(rc, leaf))
3621 counted = 0;
3622 else
3623 counted = 1;
3624 rb_node = tree_search(blocks, leaf->start);
3625 if (rb_node) {
3626 if (counted)
3627 added = 1;
3628 else
3629 path->slots[0] = nritems;
3630 }
3631 }
3632
3633 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3634 if (WARN_ON(key.objectid != ref_objectid ||
3635 key.type != BTRFS_EXTENT_DATA_KEY))
3636 break;
3637
3638 fi = btrfs_item_ptr(leaf, path->slots[0],
3639 struct btrfs_file_extent_item);
3640
3641 if (btrfs_file_extent_type(leaf, fi) ==
3642 BTRFS_FILE_EXTENT_INLINE)
3643 goto next;
3644
3645 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3646 extent_key->objectid)
3647 goto next;
3648
3649 key.offset -= btrfs_file_extent_offset(leaf, fi);
3650 if (key.offset != ref_offset)
3651 goto next;
3652
3653 if (counted)
3654 ref_count--;
3655 if (added)
3656 goto next;
3657
3658 if (!tree_block_processed(leaf->start, rc)) {
3659 block = kmalloc(sizeof(*block), GFP_NOFS);
3660 if (!block) {
3661 err = -ENOMEM;
3662 break;
3663 }
3664 block->bytenr = leaf->start;
3665 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3666 block->level = 0;
3667 block->key_ready = 1;
3668 rb_node = tree_insert(blocks, block->bytenr,
3669 &block->rb_node);
3670 if (rb_node)
3671 backref_tree_panic(rb_node, -EEXIST,
3672 block->bytenr);
3673 }
3674 if (counted)
3675 added = 1;
3676 else
3677 path->slots[0] = nritems;
3678 next:
3679 path->slots[0]++;
3680
3681 }
3682 out:
3683 btrfs_free_path(path);
3684 return err;
3685 }
3686
3687 /*
3688 * helper to find all tree blocks that reference a given data extent
3689 */
3690 static noinline_for_stack
3691 int add_data_references(struct reloc_control *rc,
3692 struct btrfs_key *extent_key,
3693 struct btrfs_path *path,
3694 struct rb_root *blocks)
3695 {
3696 struct btrfs_key key;
3697 struct extent_buffer *eb;
3698 struct btrfs_extent_data_ref *dref;
3699 struct btrfs_extent_inline_ref *iref;
3700 unsigned long ptr;
3701 unsigned long end;
3702 u32 blocksize = rc->extent_root->nodesize;
3703 int ret = 0;
3704 int err = 0;
3705
3706 eb = path->nodes[0];
3707 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3708 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3709 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3710 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3711 ptr = end;
3712 else
3713 #endif
3714 ptr += sizeof(struct btrfs_extent_item);
3715
3716 while (ptr < end) {
3717 iref = (struct btrfs_extent_inline_ref *)ptr;
3718 key.type = btrfs_extent_inline_ref_type(eb, iref);
3719 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3720 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3721 ret = __add_tree_block(rc, key.offset, blocksize,
3722 blocks);
3723 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3724 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3725 ret = find_data_references(rc, extent_key,
3726 eb, dref, blocks);
3727 } else {
3728 BUG();
3729 }
3730 if (ret) {
3731 err = ret;
3732 goto out;
3733 }
3734 ptr += btrfs_extent_inline_ref_size(key.type);
3735 }
3736 WARN_ON(ptr > end);
3737
3738 while (1) {
3739 cond_resched();
3740 eb = path->nodes[0];
3741 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3742 ret = btrfs_next_leaf(rc->extent_root, path);
3743 if (ret < 0) {
3744 err = ret;
3745 break;
3746 }
3747 if (ret > 0)
3748 break;
3749 eb = path->nodes[0];
3750 }
3751
3752 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3753 if (key.objectid != extent_key->objectid)
3754 break;
3755
3756 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3757 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3758 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3759 #else
3760 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3761 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3762 #endif
3763 ret = __add_tree_block(rc, key.offset, blocksize,
3764 blocks);
3765 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3766 dref = btrfs_item_ptr(eb, path->slots[0],
3767 struct btrfs_extent_data_ref);
3768 ret = find_data_references(rc, extent_key,
3769 eb, dref, blocks);
3770 } else {
3771 ret = 0;
3772 }
3773 if (ret) {
3774 err = ret;
3775 break;
3776 }
3777 path->slots[0]++;
3778 }
3779 out:
3780 btrfs_release_path(path);
3781 if (err)
3782 free_block_list(blocks);
3783 return err;
3784 }
3785
3786 /*
3787 * helper to find next unprocessed extent
3788 */
3789 static noinline_for_stack
3790 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3791 struct btrfs_key *extent_key)
3792 {
3793 struct btrfs_key key;
3794 struct extent_buffer *leaf;
3795 u64 start, end, last;
3796 int ret;
3797
3798 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3799 while (1) {
3800 cond_resched();
3801 if (rc->search_start >= last) {
3802 ret = 1;
3803 break;
3804 }
3805
3806 key.objectid = rc->search_start;
3807 key.type = BTRFS_EXTENT_ITEM_KEY;
3808 key.offset = 0;
3809
3810 path->search_commit_root = 1;
3811 path->skip_locking = 1;
3812 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3813 0, 0);
3814 if (ret < 0)
3815 break;
3816 next:
3817 leaf = path->nodes[0];
3818 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3819 ret = btrfs_next_leaf(rc->extent_root, path);
3820 if (ret != 0)
3821 break;
3822 leaf = path->nodes[0];
3823 }
3824
3825 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3826 if (key.objectid >= last) {
3827 ret = 1;
3828 break;
3829 }
3830
3831 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3832 key.type != BTRFS_METADATA_ITEM_KEY) {
3833 path->slots[0]++;
3834 goto next;
3835 }
3836
3837 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3838 key.objectid + key.offset <= rc->search_start) {
3839 path->slots[0]++;
3840 goto next;
3841 }
3842
3843 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3844 key.objectid + rc->extent_root->nodesize <=
3845 rc->search_start) {
3846 path->slots[0]++;
3847 goto next;
3848 }
3849
3850 ret = find_first_extent_bit(&rc->processed_blocks,
3851 key.objectid, &start, &end,
3852 EXTENT_DIRTY, NULL);
3853
3854 if (ret == 0 && start <= key.objectid) {
3855 btrfs_release_path(path);
3856 rc->search_start = end + 1;
3857 } else {
3858 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3859 rc->search_start = key.objectid + key.offset;
3860 else
3861 rc->search_start = key.objectid +
3862 rc->extent_root->nodesize;
3863 memcpy(extent_key, &key, sizeof(key));
3864 return 0;
3865 }
3866 }
3867 btrfs_release_path(path);
3868 return ret;
3869 }
3870
3871 static void set_reloc_control(struct reloc_control *rc)
3872 {
3873 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3874
3875 mutex_lock(&fs_info->reloc_mutex);
3876 fs_info->reloc_ctl = rc;
3877 mutex_unlock(&fs_info->reloc_mutex);
3878 }
3879
3880 static void unset_reloc_control(struct reloc_control *rc)
3881 {
3882 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3883
3884 mutex_lock(&fs_info->reloc_mutex);
3885 fs_info->reloc_ctl = NULL;
3886 mutex_unlock(&fs_info->reloc_mutex);
3887 }
3888
3889 static int check_extent_flags(u64 flags)
3890 {
3891 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3892 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3893 return 1;
3894 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3895 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3896 return 1;
3897 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3898 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3899 return 1;
3900 return 0;
3901 }
3902
3903 static noinline_for_stack
3904 int prepare_to_relocate(struct reloc_control *rc)
3905 {
3906 struct btrfs_trans_handle *trans;
3907 int ret;
3908
3909 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3910 BTRFS_BLOCK_RSV_TEMP);
3911 if (!rc->block_rsv)
3912 return -ENOMEM;
3913
3914 memset(&rc->cluster, 0, sizeof(rc->cluster));
3915 rc->search_start = rc->block_group->key.objectid;
3916 rc->extents_found = 0;
3917 rc->nodes_relocated = 0;
3918 rc->merging_rsv_size = 0;
3919 rc->reserved_bytes = 0;
3920 rc->block_rsv->size = rc->extent_root->nodesize *
3921 RELOCATION_RESERVED_NODES;
3922 ret = btrfs_block_rsv_refill(rc->extent_root,
3923 rc->block_rsv, rc->block_rsv->size,
3924 BTRFS_RESERVE_FLUSH_ALL);
3925 if (ret)
3926 return ret;
3927
3928 rc->create_reloc_tree = 1;
3929 set_reloc_control(rc);
3930
3931 trans = btrfs_join_transaction(rc->extent_root);
3932 if (IS_ERR(trans)) {
3933 unset_reloc_control(rc);
3934 /*
3935 * extent tree is not a ref_cow tree and has no reloc_root to
3936 * cleanup. And callers are responsible to free the above
3937 * block rsv.
3938 */
3939 return PTR_ERR(trans);
3940 }
3941 btrfs_commit_transaction(trans, rc->extent_root);
3942 return 0;
3943 }
3944
3945 /*
3946 * Qgroup fixer for data chunk relocation.
3947 * The data relocation is done in the following steps
3948 * 1) Copy data extents into data reloc tree
3949 * 2) Create tree reloc tree(special snapshot) for related subvolumes
3950 * 3) Modify file extents in tree reloc tree
3951 * 4) Merge tree reloc tree with original fs tree, by swapping tree blocks
3952 *
3953 * The problem is, data and tree reloc tree are not accounted to qgroup,
3954 * and 4) will only info qgroup to track tree blocks change, not file extents
3955 * in the tree blocks.
3956 *
3957 * The good news is, related data extents are all in data reloc tree, so we
3958 * only need to info qgroup to track all file extents in data reloc tree
3959 * before commit trans.
3960 */
3961 static int qgroup_fix_relocated_data_extents(struct btrfs_trans_handle *trans,
3962 struct reloc_control *rc)
3963 {
3964 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3965 struct inode *inode = rc->data_inode;
3966 struct btrfs_root *data_reloc_root = BTRFS_I(inode)->root;
3967 struct btrfs_path *path;
3968 struct btrfs_key key;
3969 int ret = 0;
3970
3971 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
3972 return 0;
3973
3974 /*
3975 * Only for stage where we update data pointers the qgroup fix is
3976 * valid.
3977 * For MOVING_DATA stage, we will miss the timing of swapping tree
3978 * blocks, and won't fix it.
3979 */
3980 if (!(rc->stage == UPDATE_DATA_PTRS && rc->extents_found))
3981 return 0;
3982
3983 path = btrfs_alloc_path();
3984 if (!path)
3985 return -ENOMEM;
3986 key.objectid = btrfs_ino(inode);
3987 key.type = BTRFS_EXTENT_DATA_KEY;
3988 key.offset = 0;
3989
3990 ret = btrfs_search_slot(NULL, data_reloc_root, &key, path, 0, 0);
3991 if (ret < 0)
3992 goto out;
3993
3994 lock_extent(&BTRFS_I(inode)->io_tree, 0, (u64)-1);
3995 while (1) {
3996 struct btrfs_file_extent_item *fi;
3997
3998 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3999 if (key.objectid > btrfs_ino(inode))
4000 break;
4001 if (key.type != BTRFS_EXTENT_DATA_KEY)
4002 goto next;
4003 fi = btrfs_item_ptr(path->nodes[0], path->slots[0],
4004 struct btrfs_file_extent_item);
4005 if (btrfs_file_extent_type(path->nodes[0], fi) !=
4006 BTRFS_FILE_EXTENT_REG)
4007 goto next;
4008 ret = btrfs_qgroup_insert_dirty_extent(trans, fs_info,
4009 btrfs_file_extent_disk_bytenr(path->nodes[0], fi),
4010 btrfs_file_extent_disk_num_bytes(path->nodes[0], fi),
4011 GFP_NOFS);
4012 if (ret < 0)
4013 break;
4014 next:
4015 ret = btrfs_next_item(data_reloc_root, path);
4016 if (ret < 0)
4017 break;
4018 if (ret > 0) {
4019 ret = 0;
4020 break;
4021 }
4022 }
4023 unlock_extent(&BTRFS_I(inode)->io_tree, 0 , (u64)-1);
4024 out:
4025 btrfs_free_path(path);
4026 return ret;
4027 }
4028
4029 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4030 {
4031 struct rb_root blocks = RB_ROOT;
4032 struct btrfs_key key;
4033 struct btrfs_trans_handle *trans = NULL;
4034 struct btrfs_path *path;
4035 struct btrfs_extent_item *ei;
4036 u64 flags;
4037 u32 item_size;
4038 int ret;
4039 int err = 0;
4040 int progress = 0;
4041
4042 path = btrfs_alloc_path();
4043 if (!path)
4044 return -ENOMEM;
4045 path->reada = READA_FORWARD;
4046
4047 ret = prepare_to_relocate(rc);
4048 if (ret) {
4049 err = ret;
4050 goto out_free;
4051 }
4052
4053 while (1) {
4054 rc->reserved_bytes = 0;
4055 ret = btrfs_block_rsv_refill(rc->extent_root,
4056 rc->block_rsv, rc->block_rsv->size,
4057 BTRFS_RESERVE_FLUSH_ALL);
4058 if (ret) {
4059 err = ret;
4060 break;
4061 }
4062 progress++;
4063 trans = btrfs_start_transaction(rc->extent_root, 0);
4064 if (IS_ERR(trans)) {
4065 err = PTR_ERR(trans);
4066 trans = NULL;
4067 break;
4068 }
4069 restart:
4070 if (update_backref_cache(trans, &rc->backref_cache)) {
4071 btrfs_end_transaction(trans, rc->extent_root);
4072 continue;
4073 }
4074
4075 ret = find_next_extent(rc, path, &key);
4076 if (ret < 0)
4077 err = ret;
4078 if (ret != 0)
4079 break;
4080
4081 rc->extents_found++;
4082
4083 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4084 struct btrfs_extent_item);
4085 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4086 if (item_size >= sizeof(*ei)) {
4087 flags = btrfs_extent_flags(path->nodes[0], ei);
4088 ret = check_extent_flags(flags);
4089 BUG_ON(ret);
4090
4091 } else {
4092 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4093 u64 ref_owner;
4094 int path_change = 0;
4095
4096 BUG_ON(item_size !=
4097 sizeof(struct btrfs_extent_item_v0));
4098 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
4099 &path_change);
4100 if (ret < 0) {
4101 err = ret;
4102 break;
4103 }
4104 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
4105 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
4106 else
4107 flags = BTRFS_EXTENT_FLAG_DATA;
4108
4109 if (path_change) {
4110 btrfs_release_path(path);
4111
4112 path->search_commit_root = 1;
4113 path->skip_locking = 1;
4114 ret = btrfs_search_slot(NULL, rc->extent_root,
4115 &key, path, 0, 0);
4116 if (ret < 0) {
4117 err = ret;
4118 break;
4119 }
4120 BUG_ON(ret > 0);
4121 }
4122 #else
4123 BUG();
4124 #endif
4125 }
4126
4127 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4128 ret = add_tree_block(rc, &key, path, &blocks);
4129 } else if (rc->stage == UPDATE_DATA_PTRS &&
4130 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4131 ret = add_data_references(rc, &key, path, &blocks);
4132 } else {
4133 btrfs_release_path(path);
4134 ret = 0;
4135 }
4136 if (ret < 0) {
4137 err = ret;
4138 break;
4139 }
4140
4141 if (!RB_EMPTY_ROOT(&blocks)) {
4142 ret = relocate_tree_blocks(trans, rc, &blocks);
4143 if (ret < 0) {
4144 /*
4145 * if we fail to relocate tree blocks, force to update
4146 * backref cache when committing transaction.
4147 */
4148 rc->backref_cache.last_trans = trans->transid - 1;
4149
4150 if (ret != -EAGAIN) {
4151 err = ret;
4152 break;
4153 }
4154 rc->extents_found--;
4155 rc->search_start = key.objectid;
4156 }
4157 }
4158
4159 btrfs_end_transaction_throttle(trans, rc->extent_root);
4160 btrfs_btree_balance_dirty(rc->extent_root);
4161 trans = NULL;
4162
4163 if (rc->stage == MOVE_DATA_EXTENTS &&
4164 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4165 rc->found_file_extent = 1;
4166 ret = relocate_data_extent(rc->data_inode,
4167 &key, &rc->cluster);
4168 if (ret < 0) {
4169 err = ret;
4170 break;
4171 }
4172 }
4173 }
4174 if (trans && progress && err == -ENOSPC) {
4175 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
4176 rc->block_group->flags);
4177 if (ret == 1) {
4178 err = 0;
4179 progress = 0;
4180 goto restart;
4181 }
4182 }
4183
4184 btrfs_release_path(path);
4185 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4186
4187 if (trans) {
4188 btrfs_end_transaction_throttle(trans, rc->extent_root);
4189 btrfs_btree_balance_dirty(rc->extent_root);
4190 }
4191
4192 if (!err) {
4193 ret = relocate_file_extent_cluster(rc->data_inode,
4194 &rc->cluster);
4195 if (ret < 0)
4196 err = ret;
4197 }
4198
4199 rc->create_reloc_tree = 0;
4200 set_reloc_control(rc);
4201
4202 backref_cache_cleanup(&rc->backref_cache);
4203 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4204
4205 err = prepare_to_merge(rc, err);
4206
4207 merge_reloc_roots(rc);
4208
4209 rc->merge_reloc_tree = 0;
4210 unset_reloc_control(rc);
4211 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4212
4213 /* get rid of pinned extents */
4214 trans = btrfs_join_transaction(rc->extent_root);
4215 if (IS_ERR(trans)) {
4216 err = PTR_ERR(trans);
4217 goto out_free;
4218 }
4219 ret = qgroup_fix_relocated_data_extents(trans, rc);
4220 if (ret < 0) {
4221 btrfs_abort_transaction(trans, ret);
4222 if (!err)
4223 err = ret;
4224 goto out_free;
4225 }
4226 btrfs_commit_transaction(trans, rc->extent_root);
4227 out_free:
4228 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
4229 btrfs_free_path(path);
4230 return err;
4231 }
4232
4233 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4234 struct btrfs_root *root, u64 objectid)
4235 {
4236 struct btrfs_path *path;
4237 struct btrfs_inode_item *item;
4238 struct extent_buffer *leaf;
4239 int ret;
4240
4241 path = btrfs_alloc_path();
4242 if (!path)
4243 return -ENOMEM;
4244
4245 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4246 if (ret)
4247 goto out;
4248
4249 leaf = path->nodes[0];
4250 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4251 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4252 btrfs_set_inode_generation(leaf, item, 1);
4253 btrfs_set_inode_size(leaf, item, 0);
4254 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4255 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4256 BTRFS_INODE_PREALLOC);
4257 btrfs_mark_buffer_dirty(leaf);
4258 out:
4259 btrfs_free_path(path);
4260 return ret;
4261 }
4262
4263 /*
4264 * helper to create inode for data relocation.
4265 * the inode is in data relocation tree and its link count is 0
4266 */
4267 static noinline_for_stack
4268 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4269 struct btrfs_block_group_cache *group)
4270 {
4271 struct inode *inode = NULL;
4272 struct btrfs_trans_handle *trans;
4273 struct btrfs_root *root;
4274 struct btrfs_key key;
4275 u64 objectid;
4276 int err = 0;
4277
4278 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4279 if (IS_ERR(root))
4280 return ERR_CAST(root);
4281
4282 trans = btrfs_start_transaction(root, 6);
4283 if (IS_ERR(trans))
4284 return ERR_CAST(trans);
4285
4286 err = btrfs_find_free_objectid(root, &objectid);
4287 if (err)
4288 goto out;
4289
4290 err = __insert_orphan_inode(trans, root, objectid);
4291 BUG_ON(err);
4292
4293 key.objectid = objectid;
4294 key.type = BTRFS_INODE_ITEM_KEY;
4295 key.offset = 0;
4296 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
4297 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4298 BTRFS_I(inode)->index_cnt = group->key.objectid;
4299
4300 err = btrfs_orphan_add(trans, inode);
4301 out:
4302 btrfs_end_transaction(trans, root);
4303 btrfs_btree_balance_dirty(root);
4304 if (err) {
4305 if (inode)
4306 iput(inode);
4307 inode = ERR_PTR(err);
4308 }
4309 return inode;
4310 }
4311
4312 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4313 {
4314 struct reloc_control *rc;
4315
4316 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4317 if (!rc)
4318 return NULL;
4319
4320 INIT_LIST_HEAD(&rc->reloc_roots);
4321 backref_cache_init(&rc->backref_cache);
4322 mapping_tree_init(&rc->reloc_root_tree);
4323 extent_io_tree_init(&rc->processed_blocks,
4324 fs_info->btree_inode->i_mapping);
4325 return rc;
4326 }
4327
4328 /*
4329 * function to relocate all extents in a block group.
4330 */
4331 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4332 {
4333 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4334 struct reloc_control *rc;
4335 struct inode *inode;
4336 struct btrfs_path *path;
4337 int ret;
4338 int rw = 0;
4339 int err = 0;
4340
4341 rc = alloc_reloc_control(fs_info);
4342 if (!rc)
4343 return -ENOMEM;
4344
4345 rc->extent_root = extent_root;
4346
4347 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4348 BUG_ON(!rc->block_group);
4349
4350 ret = btrfs_inc_block_group_ro(extent_root, rc->block_group);
4351 if (ret) {
4352 err = ret;
4353 goto out;
4354 }
4355 rw = 1;
4356
4357 path = btrfs_alloc_path();
4358 if (!path) {
4359 err = -ENOMEM;
4360 goto out;
4361 }
4362
4363 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4364 path);
4365 btrfs_free_path(path);
4366
4367 if (!IS_ERR(inode))
4368 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4369 else
4370 ret = PTR_ERR(inode);
4371
4372 if (ret && ret != -ENOENT) {
4373 err = ret;
4374 goto out;
4375 }
4376
4377 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4378 if (IS_ERR(rc->data_inode)) {
4379 err = PTR_ERR(rc->data_inode);
4380 rc->data_inode = NULL;
4381 goto out;
4382 }
4383
4384 btrfs_info(extent_root->fs_info,
4385 "relocating block group %llu flags %llu",
4386 rc->block_group->key.objectid, rc->block_group->flags);
4387
4388 btrfs_wait_block_group_reservations(rc->block_group);
4389 btrfs_wait_nocow_writers(rc->block_group);
4390 btrfs_wait_ordered_roots(fs_info, -1,
4391 rc->block_group->key.objectid,
4392 rc->block_group->key.offset);
4393
4394 while (1) {
4395 mutex_lock(&fs_info->cleaner_mutex);
4396 ret = relocate_block_group(rc);
4397 mutex_unlock(&fs_info->cleaner_mutex);
4398 if (ret < 0) {
4399 err = ret;
4400 goto out;
4401 }
4402
4403 if (rc->extents_found == 0)
4404 break;
4405
4406 btrfs_info(extent_root->fs_info, "found %llu extents",
4407 rc->extents_found);
4408
4409 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4410 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4411 (u64)-1);
4412 if (ret) {
4413 err = ret;
4414 goto out;
4415 }
4416 invalidate_mapping_pages(rc->data_inode->i_mapping,
4417 0, -1);
4418 rc->stage = UPDATE_DATA_PTRS;
4419 }
4420 }
4421
4422 WARN_ON(rc->block_group->pinned > 0);
4423 WARN_ON(rc->block_group->reserved > 0);
4424 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4425 out:
4426 if (err && rw)
4427 btrfs_dec_block_group_ro(extent_root, rc->block_group);
4428 iput(rc->data_inode);
4429 btrfs_put_block_group(rc->block_group);
4430 kfree(rc);
4431 return err;
4432 }
4433
4434 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4435 {
4436 struct btrfs_trans_handle *trans;
4437 int ret, err;
4438
4439 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4440 if (IS_ERR(trans))
4441 return PTR_ERR(trans);
4442
4443 memset(&root->root_item.drop_progress, 0,
4444 sizeof(root->root_item.drop_progress));
4445 root->root_item.drop_level = 0;
4446 btrfs_set_root_refs(&root->root_item, 0);
4447 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4448 &root->root_key, &root->root_item);
4449
4450 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4451 if (err)
4452 return err;
4453 return ret;
4454 }
4455
4456 /*
4457 * recover relocation interrupted by system crash.
4458 *
4459 * this function resumes merging reloc trees with corresponding fs trees.
4460 * this is important for keeping the sharing of tree blocks
4461 */
4462 int btrfs_recover_relocation(struct btrfs_root *root)
4463 {
4464 LIST_HEAD(reloc_roots);
4465 struct btrfs_key key;
4466 struct btrfs_root *fs_root;
4467 struct btrfs_root *reloc_root;
4468 struct btrfs_path *path;
4469 struct extent_buffer *leaf;
4470 struct reloc_control *rc = NULL;
4471 struct btrfs_trans_handle *trans;
4472 int ret;
4473 int err = 0;
4474
4475 path = btrfs_alloc_path();
4476 if (!path)
4477 return -ENOMEM;
4478 path->reada = READA_BACK;
4479
4480 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4481 key.type = BTRFS_ROOT_ITEM_KEY;
4482 key.offset = (u64)-1;
4483
4484 while (1) {
4485 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4486 path, 0, 0);
4487 if (ret < 0) {
4488 err = ret;
4489 goto out;
4490 }
4491 if (ret > 0) {
4492 if (path->slots[0] == 0)
4493 break;
4494 path->slots[0]--;
4495 }
4496 leaf = path->nodes[0];
4497 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4498 btrfs_release_path(path);
4499
4500 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4501 key.type != BTRFS_ROOT_ITEM_KEY)
4502 break;
4503
4504 reloc_root = btrfs_read_fs_root(root, &key);
4505 if (IS_ERR(reloc_root)) {
4506 err = PTR_ERR(reloc_root);
4507 goto out;
4508 }
4509
4510 list_add(&reloc_root->root_list, &reloc_roots);
4511
4512 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4513 fs_root = read_fs_root(root->fs_info,
4514 reloc_root->root_key.offset);
4515 if (IS_ERR(fs_root)) {
4516 ret = PTR_ERR(fs_root);
4517 if (ret != -ENOENT) {
4518 err = ret;
4519 goto out;
4520 }
4521 ret = mark_garbage_root(reloc_root);
4522 if (ret < 0) {
4523 err = ret;
4524 goto out;
4525 }
4526 }
4527 }
4528
4529 if (key.offset == 0)
4530 break;
4531
4532 key.offset--;
4533 }
4534 btrfs_release_path(path);
4535
4536 if (list_empty(&reloc_roots))
4537 goto out;
4538
4539 rc = alloc_reloc_control(root->fs_info);
4540 if (!rc) {
4541 err = -ENOMEM;
4542 goto out;
4543 }
4544
4545 rc->extent_root = root->fs_info->extent_root;
4546
4547 set_reloc_control(rc);
4548
4549 trans = btrfs_join_transaction(rc->extent_root);
4550 if (IS_ERR(trans)) {
4551 unset_reloc_control(rc);
4552 err = PTR_ERR(trans);
4553 goto out_free;
4554 }
4555
4556 rc->merge_reloc_tree = 1;
4557
4558 while (!list_empty(&reloc_roots)) {
4559 reloc_root = list_entry(reloc_roots.next,
4560 struct btrfs_root, root_list);
4561 list_del(&reloc_root->root_list);
4562
4563 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4564 list_add_tail(&reloc_root->root_list,
4565 &rc->reloc_roots);
4566 continue;
4567 }
4568
4569 fs_root = read_fs_root(root->fs_info,
4570 reloc_root->root_key.offset);
4571 if (IS_ERR(fs_root)) {
4572 err = PTR_ERR(fs_root);
4573 goto out_free;
4574 }
4575
4576 err = __add_reloc_root(reloc_root);
4577 BUG_ON(err < 0); /* -ENOMEM or logic error */
4578 fs_root->reloc_root = reloc_root;
4579 }
4580
4581 err = btrfs_commit_transaction(trans, rc->extent_root);
4582 if (err)
4583 goto out_free;
4584
4585 merge_reloc_roots(rc);
4586
4587 unset_reloc_control(rc);
4588
4589 trans = btrfs_join_transaction(rc->extent_root);
4590 if (IS_ERR(trans)) {
4591 err = PTR_ERR(trans);
4592 goto out_free;
4593 }
4594 err = qgroup_fix_relocated_data_extents(trans, rc);
4595 if (err < 0) {
4596 btrfs_abort_transaction(trans, err);
4597 goto out_free;
4598 }
4599 err = btrfs_commit_transaction(trans, rc->extent_root);
4600 out_free:
4601 kfree(rc);
4602 out:
4603 if (!list_empty(&reloc_roots))
4604 free_reloc_roots(&reloc_roots);
4605
4606 btrfs_free_path(path);
4607
4608 if (err == 0) {
4609 /* cleanup orphan inode in data relocation tree */
4610 fs_root = read_fs_root(root->fs_info,
4611 BTRFS_DATA_RELOC_TREE_OBJECTID);
4612 if (IS_ERR(fs_root))
4613 err = PTR_ERR(fs_root);
4614 else
4615 err = btrfs_orphan_cleanup(fs_root);
4616 }
4617 return err;
4618 }
4619
4620 /*
4621 * helper to add ordered checksum for data relocation.
4622 *
4623 * cloning checksum properly handles the nodatasum extents.
4624 * it also saves CPU time to re-calculate the checksum.
4625 */
4626 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4627 {
4628 struct btrfs_ordered_sum *sums;
4629 struct btrfs_ordered_extent *ordered;
4630 struct btrfs_root *root = BTRFS_I(inode)->root;
4631 int ret;
4632 u64 disk_bytenr;
4633 u64 new_bytenr;
4634 LIST_HEAD(list);
4635
4636 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4637 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4638
4639 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4640 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4641 disk_bytenr + len - 1, &list, 0);
4642 if (ret)
4643 goto out;
4644
4645 while (!list_empty(&list)) {
4646 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4647 list_del_init(&sums->list);
4648
4649 /*
4650 * We need to offset the new_bytenr based on where the csum is.
4651 * We need to do this because we will read in entire prealloc
4652 * extents but we may have written to say the middle of the
4653 * prealloc extent, so we need to make sure the csum goes with
4654 * the right disk offset.
4655 *
4656 * We can do this because the data reloc inode refers strictly
4657 * to the on disk bytes, so we don't have to worry about
4658 * disk_len vs real len like with real inodes since it's all
4659 * disk length.
4660 */
4661 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4662 sums->bytenr = new_bytenr;
4663
4664 btrfs_add_ordered_sum(inode, ordered, sums);
4665 }
4666 out:
4667 btrfs_put_ordered_extent(ordered);
4668 return ret;
4669 }
4670
4671 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4672 struct btrfs_root *root, struct extent_buffer *buf,
4673 struct extent_buffer *cow)
4674 {
4675 struct reloc_control *rc;
4676 struct backref_node *node;
4677 int first_cow = 0;
4678 int level;
4679 int ret = 0;
4680
4681 rc = root->fs_info->reloc_ctl;
4682 if (!rc)
4683 return 0;
4684
4685 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4686 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4687
4688 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4689 if (buf == root->node)
4690 __update_reloc_root(root, cow->start);
4691 }
4692
4693 level = btrfs_header_level(buf);
4694 if (btrfs_header_generation(buf) <=
4695 btrfs_root_last_snapshot(&root->root_item))
4696 first_cow = 1;
4697
4698 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4699 rc->create_reloc_tree) {
4700 WARN_ON(!first_cow && level == 0);
4701
4702 node = rc->backref_cache.path[level];
4703 BUG_ON(node->bytenr != buf->start &&
4704 node->new_bytenr != buf->start);
4705
4706 drop_node_buffer(node);
4707 extent_buffer_get(cow);
4708 node->eb = cow;
4709 node->new_bytenr = cow->start;
4710
4711 if (!node->pending) {
4712 list_move_tail(&node->list,
4713 &rc->backref_cache.pending[level]);
4714 node->pending = 1;
4715 }
4716
4717 if (first_cow)
4718 __mark_block_processed(rc, node);
4719
4720 if (first_cow && level > 0)
4721 rc->nodes_relocated += buf->len;
4722 }
4723
4724 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4725 ret = replace_file_extents(trans, rc, root, cow);
4726 return ret;
4727 }
4728
4729 /*
4730 * called before creating snapshot. it calculates metadata reservation
4731 * required for relocating tree blocks in the snapshot
4732 */
4733 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4734 u64 *bytes_to_reserve)
4735 {
4736 struct btrfs_root *root;
4737 struct reloc_control *rc;
4738
4739 root = pending->root;
4740 if (!root->reloc_root)
4741 return;
4742
4743 rc = root->fs_info->reloc_ctl;
4744 if (!rc->merge_reloc_tree)
4745 return;
4746
4747 root = root->reloc_root;
4748 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4749 /*
4750 * relocation is in the stage of merging trees. the space
4751 * used by merging a reloc tree is twice the size of
4752 * relocated tree nodes in the worst case. half for cowing
4753 * the reloc tree, half for cowing the fs tree. the space
4754 * used by cowing the reloc tree will be freed after the
4755 * tree is dropped. if we create snapshot, cowing the fs
4756 * tree may use more space than it frees. so we need
4757 * reserve extra space.
4758 */
4759 *bytes_to_reserve += rc->nodes_relocated;
4760 }
4761
4762 /*
4763 * called after snapshot is created. migrate block reservation
4764 * and create reloc root for the newly created snapshot
4765 */
4766 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4767 struct btrfs_pending_snapshot *pending)
4768 {
4769 struct btrfs_root *root = pending->root;
4770 struct btrfs_root *reloc_root;
4771 struct btrfs_root *new_root;
4772 struct reloc_control *rc;
4773 int ret;
4774
4775 if (!root->reloc_root)
4776 return 0;
4777
4778 rc = root->fs_info->reloc_ctl;
4779 rc->merging_rsv_size += rc->nodes_relocated;
4780
4781 if (rc->merge_reloc_tree) {
4782 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4783 rc->block_rsv,
4784 rc->nodes_relocated, 1);
4785 if (ret)
4786 return ret;
4787 }
4788
4789 new_root = pending->snap;
4790 reloc_root = create_reloc_root(trans, root->reloc_root,
4791 new_root->root_key.objectid);
4792 if (IS_ERR(reloc_root))
4793 return PTR_ERR(reloc_root);
4794
4795 ret = __add_reloc_root(reloc_root);
4796 BUG_ON(ret < 0);
4797 new_root->reloc_root = reloc_root;
4798
4799 if (rc->create_reloc_tree)
4800 ret = clone_backref_node(trans, rc, root, reloc_root);
4801 return ret;
4802 }
Linux with added FPC-III support