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