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Linux 3.12.28
[linux/fpc-iii.git] / fs / btrfs / relocation.c
blob225c5b2e748f0515985b34319b7f6ef537813615
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_get_fs_root(fs_info, &key, false);
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 struct btrfs_block_rsv *rsv;
1387 int clear_rsv = 0;
1388 int ret;
1389
1390 if (root->reloc_root) {
1391 reloc_root = root->reloc_root;
1392 reloc_root->last_trans = trans->transid;
1393 return 0;
1394 }
1395
1396 if (!rc || !rc->create_reloc_tree ||
1397 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1398 return 0;
1399
1400 if (!trans->reloc_reserved) {
1401 rsv = trans->block_rsv;
1402 trans->block_rsv = rc->block_rsv;
1403 clear_rsv = 1;
1404 }
1405 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1406 if (clear_rsv)
1407 trans->block_rsv = rsv;
1408
1409 ret = __add_reloc_root(reloc_root);
1410 BUG_ON(ret < 0);
1411 root->reloc_root = reloc_root;
1412 return 0;
1413 }
1414
1415 /*
1416 * update root item of reloc tree
1417 */
1418 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1419 struct btrfs_root *root)
1420 {
1421 struct btrfs_root *reloc_root;
1422 struct btrfs_root_item *root_item;
1423 int del = 0;
1424 int ret;
1425
1426 if (!root->reloc_root)
1427 goto out;
1428
1429 reloc_root = root->reloc_root;
1430 root_item = &reloc_root->root_item;
1431
1432 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1433 btrfs_root_refs(root_item) == 0) {
1434 root->reloc_root = NULL;
1435 del = 1;
1436 }
1437
1438 __update_reloc_root(reloc_root, del);
1439
1440 if (reloc_root->commit_root != reloc_root->node) {
1441 btrfs_set_root_node(root_item, reloc_root->node);
1442 free_extent_buffer(reloc_root->commit_root);
1443 reloc_root->commit_root = btrfs_root_node(reloc_root);
1444 }
1445
1446 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1447 &reloc_root->root_key, root_item);
1448 BUG_ON(ret);
1449
1450 out:
1451 return 0;
1452 }
1453
1454 /*
1455 * helper to find first cached inode with inode number >= objectid
1456 * in a subvolume
1457 */
1458 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1459 {
1460 struct rb_node *node;
1461 struct rb_node *prev;
1462 struct btrfs_inode *entry;
1463 struct inode *inode;
1464
1465 spin_lock(&root->inode_lock);
1466 again:
1467 node = root->inode_tree.rb_node;
1468 prev = NULL;
1469 while (node) {
1470 prev = node;
1471 entry = rb_entry(node, struct btrfs_inode, rb_node);
1472
1473 if (objectid < btrfs_ino(&entry->vfs_inode))
1474 node = node->rb_left;
1475 else if (objectid > btrfs_ino(&entry->vfs_inode))
1476 node = node->rb_right;
1477 else
1478 break;
1479 }
1480 if (!node) {
1481 while (prev) {
1482 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1483 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1484 node = prev;
1485 break;
1486 }
1487 prev = rb_next(prev);
1488 }
1489 }
1490 while (node) {
1491 entry = rb_entry(node, struct btrfs_inode, rb_node);
1492 inode = igrab(&entry->vfs_inode);
1493 if (inode) {
1494 spin_unlock(&root->inode_lock);
1495 return inode;
1496 }
1497
1498 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1499 if (cond_resched_lock(&root->inode_lock))
1500 goto again;
1501
1502 node = rb_next(node);
1503 }
1504 spin_unlock(&root->inode_lock);
1505 return NULL;
1506 }
1507
1508 static int in_block_group(u64 bytenr,
1509 struct btrfs_block_group_cache *block_group)
1510 {
1511 if (bytenr >= block_group->key.objectid &&
1512 bytenr < block_group->key.objectid + block_group->key.offset)
1513 return 1;
1514 return 0;
1515 }
1516
1517 /*
1518 * get new location of data
1519 */
1520 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1521 u64 bytenr, u64 num_bytes)
1522 {
1523 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1524 struct btrfs_path *path;
1525 struct btrfs_file_extent_item *fi;
1526 struct extent_buffer *leaf;
1527 int ret;
1528
1529 path = btrfs_alloc_path();
1530 if (!path)
1531 return -ENOMEM;
1532
1533 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1534 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1535 bytenr, 0);
1536 if (ret < 0)
1537 goto out;
1538 if (ret > 0) {
1539 ret = -ENOENT;
1540 goto out;
1541 }
1542
1543 leaf = path->nodes[0];
1544 fi = btrfs_item_ptr(leaf, path->slots[0],
1545 struct btrfs_file_extent_item);
1546
1547 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1548 btrfs_file_extent_compression(leaf, fi) ||
1549 btrfs_file_extent_encryption(leaf, fi) ||
1550 btrfs_file_extent_other_encoding(leaf, fi));
1551
1552 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1553 ret = -EINVAL;
1554 goto out;
1555 }
1556
1557 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1558 ret = 0;
1559 out:
1560 btrfs_free_path(path);
1561 return ret;
1562 }
1563
1564 /*
1565 * update file extent items in the tree leaf to point to
1566 * the new locations.
1567 */
1568 static noinline_for_stack
1569 int replace_file_extents(struct btrfs_trans_handle *trans,
1570 struct reloc_control *rc,
1571 struct btrfs_root *root,
1572 struct extent_buffer *leaf)
1573 {
1574 struct btrfs_key key;
1575 struct btrfs_file_extent_item *fi;
1576 struct inode *inode = NULL;
1577 u64 parent;
1578 u64 bytenr;
1579 u64 new_bytenr = 0;
1580 u64 num_bytes;
1581 u64 end;
1582 u32 nritems;
1583 u32 i;
1584 int ret = 0;
1585 int first = 1;
1586 int dirty = 0;
1587
1588 if (rc->stage != UPDATE_DATA_PTRS)
1589 return 0;
1590
1591 /* reloc trees always use full backref */
1592 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1593 parent = leaf->start;
1594 else
1595 parent = 0;
1596
1597 nritems = btrfs_header_nritems(leaf);
1598 for (i = 0; i < nritems; i++) {
1599 cond_resched();
1600 btrfs_item_key_to_cpu(leaf, &key, i);
1601 if (key.type != BTRFS_EXTENT_DATA_KEY)
1602 continue;
1603 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1604 if (btrfs_file_extent_type(leaf, fi) ==
1605 BTRFS_FILE_EXTENT_INLINE)
1606 continue;
1607 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1608 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1609 if (bytenr == 0)
1610 continue;
1611 if (!in_block_group(bytenr, rc->block_group))
1612 continue;
1613
1614 /*
1615 * if we are modifying block in fs tree, wait for readpage
1616 * to complete and drop the extent cache
1617 */
1618 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1619 if (first) {
1620 inode = find_next_inode(root, key.objectid);
1621 first = 0;
1622 } else if (inode && btrfs_ino(inode) < key.objectid) {
1623 btrfs_add_delayed_iput(inode);
1624 inode = find_next_inode(root, key.objectid);
1625 }
1626 if (inode && btrfs_ino(inode) == key.objectid) {
1627 end = key.offset +
1628 btrfs_file_extent_num_bytes(leaf, fi);
1629 WARN_ON(!IS_ALIGNED(key.offset,
1630 root->sectorsize));
1631 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1632 end--;
1633 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1634 key.offset, end);
1635 if (!ret)
1636 continue;
1637
1638 btrfs_drop_extent_cache(inode, key.offset, end,
1639 1);
1640 unlock_extent(&BTRFS_I(inode)->io_tree,
1641 key.offset, end);
1642 }
1643 }
1644
1645 ret = get_new_location(rc->data_inode, &new_bytenr,
1646 bytenr, num_bytes);
1647 if (ret) {
1648 /*
1649 * Don't have to abort since we've not changed anything
1650 * in the file extent yet.
1651 */
1652 break;
1653 }
1654
1655 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1656 dirty = 1;
1657
1658 key.offset -= btrfs_file_extent_offset(leaf, fi);
1659 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1660 num_bytes, parent,
1661 btrfs_header_owner(leaf),
1662 key.objectid, key.offset, 1);
1663 if (ret) {
1664 btrfs_abort_transaction(trans, root, ret);
1665 break;
1666 }
1667
1668 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1669 parent, btrfs_header_owner(leaf),
1670 key.objectid, key.offset, 1);
1671 if (ret) {
1672 btrfs_abort_transaction(trans, root, ret);
1673 break;
1674 }
1675 }
1676 if (dirty)
1677 btrfs_mark_buffer_dirty(leaf);
1678 if (inode)
1679 btrfs_add_delayed_iput(inode);
1680 return ret;
1681 }
1682
1683 static noinline_for_stack
1684 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1685 struct btrfs_path *path, int level)
1686 {
1687 struct btrfs_disk_key key1;
1688 struct btrfs_disk_key key2;
1689 btrfs_node_key(eb, &key1, slot);
1690 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1691 return memcmp(&key1, &key2, sizeof(key1));
1692 }
1693
1694 /*
1695 * try to replace tree blocks in fs tree with the new blocks
1696 * in reloc tree. tree blocks haven't been modified since the
1697 * reloc tree was create can be replaced.
1698 *
1699 * if a block was replaced, level of the block + 1 is returned.
1700 * if no block got replaced, 0 is returned. if there are other
1701 * errors, a negative error number is returned.
1702 */
1703 static noinline_for_stack
1704 int replace_path(struct btrfs_trans_handle *trans,
1705 struct btrfs_root *dest, struct btrfs_root *src,
1706 struct btrfs_path *path, struct btrfs_key *next_key,
1707 int lowest_level, int max_level)
1708 {
1709 struct extent_buffer *eb;
1710 struct extent_buffer *parent;
1711 struct btrfs_key key;
1712 u64 old_bytenr;
1713 u64 new_bytenr;
1714 u64 old_ptr_gen;
1715 u64 new_ptr_gen;
1716 u64 last_snapshot;
1717 u32 blocksize;
1718 int cow = 0;
1719 int level;
1720 int ret;
1721 int slot;
1722
1723 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1724 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1725
1726 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1727 again:
1728 slot = path->slots[lowest_level];
1729 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1730
1731 eb = btrfs_lock_root_node(dest);
1732 btrfs_set_lock_blocking(eb);
1733 level = btrfs_header_level(eb);
1734
1735 if (level < lowest_level) {
1736 btrfs_tree_unlock(eb);
1737 free_extent_buffer(eb);
1738 return 0;
1739 }
1740
1741 if (cow) {
1742 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1743 BUG_ON(ret);
1744 }
1745 btrfs_set_lock_blocking(eb);
1746
1747 if (next_key) {
1748 next_key->objectid = (u64)-1;
1749 next_key->type = (u8)-1;
1750 next_key->offset = (u64)-1;
1751 }
1752
1753 parent = eb;
1754 while (1) {
1755 level = btrfs_header_level(parent);
1756 BUG_ON(level < lowest_level);
1757
1758 ret = btrfs_bin_search(parent, &key, level, &slot);
1759 if (ret && slot > 0)
1760 slot--;
1761
1762 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1763 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1764
1765 old_bytenr = btrfs_node_blockptr(parent, slot);
1766 blocksize = btrfs_level_size(dest, level - 1);
1767 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1768
1769 if (level <= max_level) {
1770 eb = path->nodes[level];
1771 new_bytenr = btrfs_node_blockptr(eb,
1772 path->slots[level]);
1773 new_ptr_gen = btrfs_node_ptr_generation(eb,
1774 path->slots[level]);
1775 } else {
1776 new_bytenr = 0;
1777 new_ptr_gen = 0;
1778 }
1779
1780 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1781 WARN_ON(1);
1782 ret = level;
1783 break;
1784 }
1785
1786 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1787 memcmp_node_keys(parent, slot, path, level)) {
1788 if (level <= lowest_level) {
1789 ret = 0;
1790 break;
1791 }
1792
1793 eb = read_tree_block(dest, old_bytenr, blocksize,
1794 old_ptr_gen);
1795 if (!eb || !extent_buffer_uptodate(eb)) {
1796 ret = (!eb) ? -ENOMEM : -EIO;
1797 free_extent_buffer(eb);
1798 break;
1799 }
1800 btrfs_tree_lock(eb);
1801 if (cow) {
1802 ret = btrfs_cow_block(trans, dest, eb, parent,
1803 slot, &eb);
1804 BUG_ON(ret);
1805 }
1806 btrfs_set_lock_blocking(eb);
1807
1808 btrfs_tree_unlock(parent);
1809 free_extent_buffer(parent);
1810
1811 parent = eb;
1812 continue;
1813 }
1814
1815 if (!cow) {
1816 btrfs_tree_unlock(parent);
1817 free_extent_buffer(parent);
1818 cow = 1;
1819 goto again;
1820 }
1821
1822 btrfs_node_key_to_cpu(path->nodes[level], &key,
1823 path->slots[level]);
1824 btrfs_release_path(path);
1825
1826 path->lowest_level = level;
1827 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1828 path->lowest_level = 0;
1829 BUG_ON(ret);
1830
1831 /*
1832 * swap blocks in fs tree and reloc tree.
1833 */
1834 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1835 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1836 btrfs_mark_buffer_dirty(parent);
1837
1838 btrfs_set_node_blockptr(path->nodes[level],
1839 path->slots[level], old_bytenr);
1840 btrfs_set_node_ptr_generation(path->nodes[level],
1841 path->slots[level], old_ptr_gen);
1842 btrfs_mark_buffer_dirty(path->nodes[level]);
1843
1844 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1845 path->nodes[level]->start,
1846 src->root_key.objectid, level - 1, 0,
1847 1);
1848 BUG_ON(ret);
1849 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1850 0, dest->root_key.objectid, level - 1,
1851 0, 1);
1852 BUG_ON(ret);
1853
1854 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1855 path->nodes[level]->start,
1856 src->root_key.objectid, level - 1, 0,
1857 1);
1858 BUG_ON(ret);
1859
1860 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1861 0, dest->root_key.objectid, level - 1,
1862 0, 1);
1863 BUG_ON(ret);
1864
1865 btrfs_unlock_up_safe(path, 0);
1866
1867 ret = level;
1868 break;
1869 }
1870 btrfs_tree_unlock(parent);
1871 free_extent_buffer(parent);
1872 return ret;
1873 }
1874
1875 /*
1876 * helper to find next relocated block in reloc tree
1877 */
1878 static noinline_for_stack
1879 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1880 int *level)
1881 {
1882 struct extent_buffer *eb;
1883 int i;
1884 u64 last_snapshot;
1885 u32 nritems;
1886
1887 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1888
1889 for (i = 0; i < *level; i++) {
1890 free_extent_buffer(path->nodes[i]);
1891 path->nodes[i] = NULL;
1892 }
1893
1894 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1895 eb = path->nodes[i];
1896 nritems = btrfs_header_nritems(eb);
1897 while (path->slots[i] + 1 < nritems) {
1898 path->slots[i]++;
1899 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1900 last_snapshot)
1901 continue;
1902
1903 *level = i;
1904 return 0;
1905 }
1906 free_extent_buffer(path->nodes[i]);
1907 path->nodes[i] = NULL;
1908 }
1909 return 1;
1910 }
1911
1912 /*
1913 * walk down reloc tree to find relocated block of lowest level
1914 */
1915 static noinline_for_stack
1916 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1917 int *level)
1918 {
1919 struct extent_buffer *eb = NULL;
1920 int i;
1921 u64 bytenr;
1922 u64 ptr_gen = 0;
1923 u64 last_snapshot;
1924 u32 blocksize;
1925 u32 nritems;
1926
1927 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1928
1929 for (i = *level; i > 0; i--) {
1930 eb = path->nodes[i];
1931 nritems = btrfs_header_nritems(eb);
1932 while (path->slots[i] < nritems) {
1933 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1934 if (ptr_gen > last_snapshot)
1935 break;
1936 path->slots[i]++;
1937 }
1938 if (path->slots[i] >= nritems) {
1939 if (i == *level)
1940 break;
1941 *level = i + 1;
1942 return 0;
1943 }
1944 if (i == 1) {
1945 *level = i;
1946 return 0;
1947 }
1948
1949 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1950 blocksize = btrfs_level_size(root, i - 1);
1951 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1952 if (!eb || !extent_buffer_uptodate(eb)) {
1953 free_extent_buffer(eb);
1954 return -EIO;
1955 }
1956 BUG_ON(btrfs_header_level(eb) != i - 1);
1957 path->nodes[i - 1] = eb;
1958 path->slots[i - 1] = 0;
1959 }
1960 return 1;
1961 }
1962
1963 /*
1964 * invalidate extent cache for file extents whose key in range of
1965 * [min_key, max_key)
1966 */
1967 static int invalidate_extent_cache(struct btrfs_root *root,
1968 struct btrfs_key *min_key,
1969 struct btrfs_key *max_key)
1970 {
1971 struct inode *inode = NULL;
1972 u64 objectid;
1973 u64 start, end;
1974 u64 ino;
1975
1976 objectid = min_key->objectid;
1977 while (1) {
1978 cond_resched();
1979 iput(inode);
1980
1981 if (objectid > max_key->objectid)
1982 break;
1983
1984 inode = find_next_inode(root, objectid);
1985 if (!inode)
1986 break;
1987 ino = btrfs_ino(inode);
1988
1989 if (ino > max_key->objectid) {
1990 iput(inode);
1991 break;
1992 }
1993
1994 objectid = ino + 1;
1995 if (!S_ISREG(inode->i_mode))
1996 continue;
1997
1998 if (unlikely(min_key->objectid == ino)) {
1999 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2000 continue;
2001 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2002 start = 0;
2003 else {
2004 start = min_key->offset;
2005 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
2006 }
2007 } else {
2008 start = 0;
2009 }
2010
2011 if (unlikely(max_key->objectid == ino)) {
2012 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2013 continue;
2014 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2015 end = (u64)-1;
2016 } else {
2017 if (max_key->offset == 0)
2018 continue;
2019 end = max_key->offset;
2020 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
2021 end--;
2022 }
2023 } else {
2024 end = (u64)-1;
2025 }
2026
2027 /* the lock_extent waits for readpage to complete */
2028 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2029 btrfs_drop_extent_cache(inode, start, end, 1);
2030 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2031 }
2032 return 0;
2033 }
2034
2035 static int find_next_key(struct btrfs_path *path, int level,
2036 struct btrfs_key *key)
2037
2038 {
2039 while (level < BTRFS_MAX_LEVEL) {
2040 if (!path->nodes[level])
2041 break;
2042 if (path->slots[level] + 1 <
2043 btrfs_header_nritems(path->nodes[level])) {
2044 btrfs_node_key_to_cpu(path->nodes[level], key,
2045 path->slots[level] + 1);
2046 return 0;
2047 }
2048 level++;
2049 }
2050 return 1;
2051 }
2052
2053 /*
2054 * merge the relocated tree blocks in reloc tree with corresponding
2055 * fs tree.
2056 */
2057 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2058 struct btrfs_root *root)
2059 {
2060 LIST_HEAD(inode_list);
2061 struct btrfs_key key;
2062 struct btrfs_key next_key;
2063 struct btrfs_trans_handle *trans;
2064 struct btrfs_root *reloc_root;
2065 struct btrfs_root_item *root_item;
2066 struct btrfs_path *path;
2067 struct extent_buffer *leaf;
2068 int level;
2069 int max_level;
2070 int replaced = 0;
2071 int ret;
2072 int err = 0;
2073 u32 min_reserved;
2074
2075 path = btrfs_alloc_path();
2076 if (!path)
2077 return -ENOMEM;
2078 path->reada = 1;
2079
2080 reloc_root = root->reloc_root;
2081 root_item = &reloc_root->root_item;
2082
2083 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2084 level = btrfs_root_level(root_item);
2085 extent_buffer_get(reloc_root->node);
2086 path->nodes[level] = reloc_root->node;
2087 path->slots[level] = 0;
2088 } else {
2089 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2090
2091 level = root_item->drop_level;
2092 BUG_ON(level == 0);
2093 path->lowest_level = level;
2094 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2095 path->lowest_level = 0;
2096 if (ret < 0) {
2097 btrfs_free_path(path);
2098 return ret;
2099 }
2100
2101 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2102 path->slots[level]);
2103 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2104
2105 btrfs_unlock_up_safe(path, 0);
2106 }
2107
2108 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2109 memset(&next_key, 0, sizeof(next_key));
2110
2111 while (1) {
2112 trans = btrfs_start_transaction(root, 0);
2113 BUG_ON(IS_ERR(trans));
2114 trans->block_rsv = rc->block_rsv;
2115
2116 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2117 BTRFS_RESERVE_FLUSH_ALL);
2118 if (ret) {
2119 BUG_ON(ret != -EAGAIN);
2120 ret = btrfs_commit_transaction(trans, root);
2121 BUG_ON(ret);
2122 continue;
2123 }
2124
2125 replaced = 0;
2126 max_level = level;
2127
2128 ret = walk_down_reloc_tree(reloc_root, path, &level);
2129 if (ret < 0) {
2130 err = ret;
2131 goto out;
2132 }
2133 if (ret > 0)
2134 break;
2135
2136 if (!find_next_key(path, level, &key) &&
2137 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2138 ret = 0;
2139 } else {
2140 ret = replace_path(trans, root, reloc_root, path,
2141 &next_key, level, max_level);
2142 }
2143 if (ret < 0) {
2144 err = ret;
2145 goto out;
2146 }
2147
2148 if (ret > 0) {
2149 level = ret;
2150 btrfs_node_key_to_cpu(path->nodes[level], &key,
2151 path->slots[level]);
2152 replaced = 1;
2153 }
2154
2155 ret = walk_up_reloc_tree(reloc_root, path, &level);
2156 if (ret > 0)
2157 break;
2158
2159 BUG_ON(level == 0);
2160 /*
2161 * save the merging progress in the drop_progress.
2162 * this is OK since root refs == 1 in this case.
2163 */
2164 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2165 path->slots[level]);
2166 root_item->drop_level = level;
2167
2168 btrfs_end_transaction_throttle(trans, root);
2169
2170 btrfs_btree_balance_dirty(root);
2171
2172 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2173 invalidate_extent_cache(root, &key, &next_key);
2174 }
2175
2176 /*
2177 * handle the case only one block in the fs tree need to be
2178 * relocated and the block is tree root.
2179 */
2180 leaf = btrfs_lock_root_node(root);
2181 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2182 btrfs_tree_unlock(leaf);
2183 free_extent_buffer(leaf);
2184 if (ret < 0)
2185 err = ret;
2186 out:
2187 btrfs_free_path(path);
2188
2189 if (err == 0) {
2190 memset(&root_item->drop_progress, 0,
2191 sizeof(root_item->drop_progress));
2192 root_item->drop_level = 0;
2193 btrfs_set_root_refs(root_item, 0);
2194 btrfs_update_reloc_root(trans, root);
2195 }
2196
2197 btrfs_end_transaction_throttle(trans, root);
2198
2199 btrfs_btree_balance_dirty(root);
2200
2201 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2202 invalidate_extent_cache(root, &key, &next_key);
2203
2204 return err;
2205 }
2206
2207 static noinline_for_stack
2208 int prepare_to_merge(struct reloc_control *rc, int err)
2209 {
2210 struct btrfs_root *root = rc->extent_root;
2211 struct btrfs_root *reloc_root;
2212 struct btrfs_trans_handle *trans;
2213 LIST_HEAD(reloc_roots);
2214 u64 num_bytes = 0;
2215 int ret;
2216
2217 mutex_lock(&root->fs_info->reloc_mutex);
2218 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2219 rc->merging_rsv_size += rc->nodes_relocated * 2;
2220 mutex_unlock(&root->fs_info->reloc_mutex);
2221
2222 again:
2223 if (!err) {
2224 num_bytes = rc->merging_rsv_size;
2225 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2226 BTRFS_RESERVE_FLUSH_ALL);
2227 if (ret)
2228 err = ret;
2229 }
2230
2231 trans = btrfs_join_transaction(rc->extent_root);
2232 if (IS_ERR(trans)) {
2233 if (!err)
2234 btrfs_block_rsv_release(rc->extent_root,
2235 rc->block_rsv, num_bytes);
2236 return PTR_ERR(trans);
2237 }
2238
2239 if (!err) {
2240 if (num_bytes != rc->merging_rsv_size) {
2241 btrfs_end_transaction(trans, rc->extent_root);
2242 btrfs_block_rsv_release(rc->extent_root,
2243 rc->block_rsv, num_bytes);
2244 goto again;
2245 }
2246 }
2247
2248 rc->merge_reloc_tree = 1;
2249
2250 while (!list_empty(&rc->reloc_roots)) {
2251 reloc_root = list_entry(rc->reloc_roots.next,
2252 struct btrfs_root, root_list);
2253 list_del_init(&reloc_root->root_list);
2254
2255 root = read_fs_root(reloc_root->fs_info,
2256 reloc_root->root_key.offset);
2257 BUG_ON(IS_ERR(root));
2258 BUG_ON(root->reloc_root != reloc_root);
2259
2260 /*
2261 * set reference count to 1, so btrfs_recover_relocation
2262 * knows it should resumes merging
2263 */
2264 if (!err)
2265 btrfs_set_root_refs(&reloc_root->root_item, 1);
2266 btrfs_update_reloc_root(trans, root);
2267
2268 list_add(&reloc_root->root_list, &reloc_roots);
2269 }
2270
2271 list_splice(&reloc_roots, &rc->reloc_roots);
2272
2273 if (!err)
2274 btrfs_commit_transaction(trans, rc->extent_root);
2275 else
2276 btrfs_end_transaction(trans, rc->extent_root);
2277 return err;
2278 }
2279
2280 static noinline_for_stack
2281 void free_reloc_roots(struct list_head *list)
2282 {
2283 struct btrfs_root *reloc_root;
2284
2285 while (!list_empty(list)) {
2286 reloc_root = list_entry(list->next, struct btrfs_root,
2287 root_list);
2288 __update_reloc_root(reloc_root, 1);
2289 free_extent_buffer(reloc_root->node);
2290 free_extent_buffer(reloc_root->commit_root);
2291 kfree(reloc_root);
2292 }
2293 }
2294
2295 static noinline_for_stack
2296 int merge_reloc_roots(struct reloc_control *rc)
2297 {
2298 struct btrfs_trans_handle *trans;
2299 struct btrfs_root *root;
2300 struct btrfs_root *reloc_root;
2301 u64 last_snap;
2302 u64 otransid;
2303 u64 objectid;
2304 LIST_HEAD(reloc_roots);
2305 int found = 0;
2306 int ret = 0;
2307 again:
2308 root = rc->extent_root;
2309
2310 /*
2311 * this serializes us with btrfs_record_root_in_transaction,
2312 * we have to make sure nobody is in the middle of
2313 * adding their roots to the list while we are
2314 * doing this splice
2315 */
2316 mutex_lock(&root->fs_info->reloc_mutex);
2317 list_splice_init(&rc->reloc_roots, &reloc_roots);
2318 mutex_unlock(&root->fs_info->reloc_mutex);
2319
2320 while (!list_empty(&reloc_roots)) {
2321 found = 1;
2322 reloc_root = list_entry(reloc_roots.next,
2323 struct btrfs_root, root_list);
2324
2325 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2326 root = read_fs_root(reloc_root->fs_info,
2327 reloc_root->root_key.offset);
2328 BUG_ON(IS_ERR(root));
2329 BUG_ON(root->reloc_root != reloc_root);
2330
2331 ret = merge_reloc_root(rc, root);
2332 if (ret) {
2333 __update_reloc_root(reloc_root, 1);
2334 free_extent_buffer(reloc_root->node);
2335 free_extent_buffer(reloc_root->commit_root);
2336 kfree(reloc_root);
2337 goto out;
2338 }
2339 } else {
2340 list_del_init(&reloc_root->root_list);
2341 }
2342
2343 /*
2344 * we keep the old last snapshod transid in rtranid when we
2345 * created the relocation tree.
2346 */
2347 last_snap = btrfs_root_rtransid(&reloc_root->root_item);
2348 otransid = btrfs_root_otransid(&reloc_root->root_item);
2349 objectid = reloc_root->root_key.offset;
2350
2351 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2352 if (ret < 0) {
2353 if (list_empty(&reloc_root->root_list))
2354 list_add_tail(&reloc_root->root_list,
2355 &reloc_roots);
2356 goto out;
2357 } else if (!ret) {
2358 /*
2359 * recover the last snapshot tranid to avoid
2360 * the space balance break NOCOW.
2361 */
2362 root = read_fs_root(rc->extent_root->fs_info,
2363 objectid);
2364 if (IS_ERR(root))
2365 continue;
2366
2367 trans = btrfs_join_transaction(root);
2368 BUG_ON(IS_ERR(trans));
2369
2370 /* Check if the fs/file tree was snapshoted or not. */
2371 if (btrfs_root_last_snapshot(&root->root_item) ==
2372 otransid - 1)
2373 btrfs_set_root_last_snapshot(&root->root_item,
2374 last_snap);
2375
2376 btrfs_end_transaction(trans, root);
2377 }
2378 }
2379
2380 if (found) {
2381 found = 0;
2382 goto again;
2383 }
2384 out:
2385 if (ret) {
2386 btrfs_std_error(root->fs_info, ret);
2387 if (!list_empty(&reloc_roots))
2388 free_reloc_roots(&reloc_roots);
2389 }
2390
2391 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2392 return ret;
2393 }
2394
2395 static void free_block_list(struct rb_root *blocks)
2396 {
2397 struct tree_block *block;
2398 struct rb_node *rb_node;
2399 while ((rb_node = rb_first(blocks))) {
2400 block = rb_entry(rb_node, struct tree_block, rb_node);
2401 rb_erase(rb_node, blocks);
2402 kfree(block);
2403 }
2404 }
2405
2406 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2407 struct btrfs_root *reloc_root)
2408 {
2409 struct btrfs_root *root;
2410
2411 if (reloc_root->last_trans == trans->transid)
2412 return 0;
2413
2414 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2415 BUG_ON(IS_ERR(root));
2416 BUG_ON(root->reloc_root != reloc_root);
2417
2418 return btrfs_record_root_in_trans(trans, root);
2419 }
2420
2421 static noinline_for_stack
2422 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2423 struct reloc_control *rc,
2424 struct backref_node *node,
2425 struct backref_edge *edges[], int *nr)
2426 {
2427 struct backref_node *next;
2428 struct btrfs_root *root;
2429 int index = 0;
2430
2431 next = node;
2432 while (1) {
2433 cond_resched();
2434 next = walk_up_backref(next, edges, &index);
2435 root = next->root;
2436 BUG_ON(!root);
2437 BUG_ON(!root->ref_cows);
2438
2439 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2440 record_reloc_root_in_trans(trans, root);
2441 break;
2442 }
2443
2444 btrfs_record_root_in_trans(trans, root);
2445 root = root->reloc_root;
2446
2447 if (next->new_bytenr != root->node->start) {
2448 BUG_ON(next->new_bytenr);
2449 BUG_ON(!list_empty(&next->list));
2450 next->new_bytenr = root->node->start;
2451 next->root = root;
2452 list_add_tail(&next->list,
2453 &rc->backref_cache.changed);
2454 __mark_block_processed(rc, next);
2455 break;
2456 }
2457
2458 WARN_ON(1);
2459 root = NULL;
2460 next = walk_down_backref(edges, &index);
2461 if (!next || next->level <= node->level)
2462 break;
2463 }
2464 if (!root)
2465 return NULL;
2466
2467 *nr = index;
2468 next = node;
2469 /* setup backref node path for btrfs_reloc_cow_block */
2470 while (1) {
2471 rc->backref_cache.path[next->level] = next;
2472 if (--index < 0)
2473 break;
2474 next = edges[index]->node[UPPER];
2475 }
2476 return root;
2477 }
2478
2479 /*
2480 * select a tree root for relocation. return NULL if the block
2481 * is reference counted. we should use do_relocation() in this
2482 * case. return a tree root pointer if the block isn't reference
2483 * counted. return -ENOENT if the block is root of reloc tree.
2484 */
2485 static noinline_for_stack
2486 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2487 struct backref_node *node)
2488 {
2489 struct backref_node *next;
2490 struct btrfs_root *root;
2491 struct btrfs_root *fs_root = NULL;
2492 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2493 int index = 0;
2494
2495 next = node;
2496 while (1) {
2497 cond_resched();
2498 next = walk_up_backref(next, edges, &index);
2499 root = next->root;
2500 BUG_ON(!root);
2501
2502 /* no other choice for non-references counted tree */
2503 if (!root->ref_cows)
2504 return root;
2505
2506 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2507 fs_root = root;
2508
2509 if (next != node)
2510 return NULL;
2511
2512 next = walk_down_backref(edges, &index);
2513 if (!next || next->level <= node->level)
2514 break;
2515 }
2516
2517 if (!fs_root)
2518 return ERR_PTR(-ENOENT);
2519 return fs_root;
2520 }
2521
2522 static noinline_for_stack
2523 u64 calcu_metadata_size(struct reloc_control *rc,
2524 struct backref_node *node, int reserve)
2525 {
2526 struct backref_node *next = node;
2527 struct backref_edge *edge;
2528 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2529 u64 num_bytes = 0;
2530 int index = 0;
2531
2532 BUG_ON(reserve && node->processed);
2533
2534 while (next) {
2535 cond_resched();
2536 while (1) {
2537 if (next->processed && (reserve || next != node))
2538 break;
2539
2540 num_bytes += btrfs_level_size(rc->extent_root,
2541 next->level);
2542
2543 if (list_empty(&next->upper))
2544 break;
2545
2546 edge = list_entry(next->upper.next,
2547 struct backref_edge, list[LOWER]);
2548 edges[index++] = edge;
2549 next = edge->node[UPPER];
2550 }
2551 next = walk_down_backref(edges, &index);
2552 }
2553 return num_bytes;
2554 }
2555
2556 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2557 struct reloc_control *rc,
2558 struct backref_node *node)
2559 {
2560 struct btrfs_root *root = rc->extent_root;
2561 u64 num_bytes;
2562 int ret;
2563
2564 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2565
2566 trans->block_rsv = rc->block_rsv;
2567 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2568 BTRFS_RESERVE_FLUSH_ALL);
2569 if (ret) {
2570 if (ret == -EAGAIN)
2571 rc->commit_transaction = 1;
2572 return ret;
2573 }
2574
2575 return 0;
2576 }
2577
2578 static void release_metadata_space(struct reloc_control *rc,
2579 struct backref_node *node)
2580 {
2581 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2582 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2583 }
2584
2585 /*
2586 * relocate a block tree, and then update pointers in upper level
2587 * blocks that reference the block to point to the new location.
2588 *
2589 * if called by link_to_upper, the block has already been relocated.
2590 * in that case this function just updates pointers.
2591 */
2592 static int do_relocation(struct btrfs_trans_handle *trans,
2593 struct reloc_control *rc,
2594 struct backref_node *node,
2595 struct btrfs_key *key,
2596 struct btrfs_path *path, int lowest)
2597 {
2598 struct backref_node *upper;
2599 struct backref_edge *edge;
2600 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2601 struct btrfs_root *root;
2602 struct extent_buffer *eb;
2603 u32 blocksize;
2604 u64 bytenr;
2605 u64 generation;
2606 int nr;
2607 int slot;
2608 int ret;
2609 int err = 0;
2610
2611 BUG_ON(lowest && node->eb);
2612
2613 path->lowest_level = node->level + 1;
2614 rc->backref_cache.path[node->level] = node;
2615 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2616 cond_resched();
2617
2618 upper = edge->node[UPPER];
2619 root = select_reloc_root(trans, rc, upper, edges, &nr);
2620 BUG_ON(!root);
2621
2622 if (upper->eb && !upper->locked) {
2623 if (!lowest) {
2624 ret = btrfs_bin_search(upper->eb, key,
2625 upper->level, &slot);
2626 BUG_ON(ret);
2627 bytenr = btrfs_node_blockptr(upper->eb, slot);
2628 if (node->eb->start == bytenr)
2629 goto next;
2630 }
2631 drop_node_buffer(upper);
2632 }
2633
2634 if (!upper->eb) {
2635 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2636 if (ret < 0) {
2637 err = ret;
2638 break;
2639 }
2640 BUG_ON(ret > 0);
2641
2642 if (!upper->eb) {
2643 upper->eb = path->nodes[upper->level];
2644 path->nodes[upper->level] = NULL;
2645 } else {
2646 BUG_ON(upper->eb != path->nodes[upper->level]);
2647 }
2648
2649 upper->locked = 1;
2650 path->locks[upper->level] = 0;
2651
2652 slot = path->slots[upper->level];
2653 btrfs_release_path(path);
2654 } else {
2655 ret = btrfs_bin_search(upper->eb, key, upper->level,
2656 &slot);
2657 BUG_ON(ret);
2658 }
2659
2660 bytenr = btrfs_node_blockptr(upper->eb, slot);
2661 if (lowest) {
2662 BUG_ON(bytenr != node->bytenr);
2663 } else {
2664 if (node->eb->start == bytenr)
2665 goto next;
2666 }
2667
2668 blocksize = btrfs_level_size(root, node->level);
2669 generation = btrfs_node_ptr_generation(upper->eb, slot);
2670 eb = read_tree_block(root, bytenr, blocksize, generation);
2671 if (!eb || !extent_buffer_uptodate(eb)) {
2672 free_extent_buffer(eb);
2673 err = -EIO;
2674 goto next;
2675 }
2676 btrfs_tree_lock(eb);
2677 btrfs_set_lock_blocking(eb);
2678
2679 if (!node->eb) {
2680 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2681 slot, &eb);
2682 btrfs_tree_unlock(eb);
2683 free_extent_buffer(eb);
2684 if (ret < 0) {
2685 err = ret;
2686 goto next;
2687 }
2688 BUG_ON(node->eb != eb);
2689 } else {
2690 btrfs_set_node_blockptr(upper->eb, slot,
2691 node->eb->start);
2692 btrfs_set_node_ptr_generation(upper->eb, slot,
2693 trans->transid);
2694 btrfs_mark_buffer_dirty(upper->eb);
2695
2696 ret = btrfs_inc_extent_ref(trans, root,
2697 node->eb->start, blocksize,
2698 upper->eb->start,
2699 btrfs_header_owner(upper->eb),
2700 node->level, 0, 1);
2701 BUG_ON(ret);
2702
2703 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2704 BUG_ON(ret);
2705 }
2706 next:
2707 if (!upper->pending)
2708 drop_node_buffer(upper);
2709 else
2710 unlock_node_buffer(upper);
2711 if (err)
2712 break;
2713 }
2714
2715 if (!err && node->pending) {
2716 drop_node_buffer(node);
2717 list_move_tail(&node->list, &rc->backref_cache.changed);
2718 node->pending = 0;
2719 }
2720
2721 path->lowest_level = 0;
2722 BUG_ON(err == -ENOSPC);
2723 return err;
2724 }
2725
2726 static int link_to_upper(struct btrfs_trans_handle *trans,
2727 struct reloc_control *rc,
2728 struct backref_node *node,
2729 struct btrfs_path *path)
2730 {
2731 struct btrfs_key key;
2732
2733 btrfs_node_key_to_cpu(node->eb, &key, 0);
2734 return do_relocation(trans, rc, node, &key, path, 0);
2735 }
2736
2737 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2738 struct reloc_control *rc,
2739 struct btrfs_path *path, int err)
2740 {
2741 LIST_HEAD(list);
2742 struct backref_cache *cache = &rc->backref_cache;
2743 struct backref_node *node;
2744 int level;
2745 int ret;
2746
2747 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2748 while (!list_empty(&cache->pending[level])) {
2749 node = list_entry(cache->pending[level].next,
2750 struct backref_node, list);
2751 list_move_tail(&node->list, &list);
2752 BUG_ON(!node->pending);
2753
2754 if (!err) {
2755 ret = link_to_upper(trans, rc, node, path);
2756 if (ret < 0)
2757 err = ret;
2758 }
2759 }
2760 list_splice_init(&list, &cache->pending[level]);
2761 }
2762 return err;
2763 }
2764
2765 static void mark_block_processed(struct reloc_control *rc,
2766 u64 bytenr, u32 blocksize)
2767 {
2768 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2769 EXTENT_DIRTY, GFP_NOFS);
2770 }
2771
2772 static void __mark_block_processed(struct reloc_control *rc,
2773 struct backref_node *node)
2774 {
2775 u32 blocksize;
2776 if (node->level == 0 ||
2777 in_block_group(node->bytenr, rc->block_group)) {
2778 blocksize = btrfs_level_size(rc->extent_root, node->level);
2779 mark_block_processed(rc, node->bytenr, blocksize);
2780 }
2781 node->processed = 1;
2782 }
2783
2784 /*
2785 * mark a block and all blocks directly/indirectly reference the block
2786 * as processed.
2787 */
2788 static void update_processed_blocks(struct reloc_control *rc,
2789 struct backref_node *node)
2790 {
2791 struct backref_node *next = node;
2792 struct backref_edge *edge;
2793 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2794 int index = 0;
2795
2796 while (next) {
2797 cond_resched();
2798 while (1) {
2799 if (next->processed)
2800 break;
2801
2802 __mark_block_processed(rc, next);
2803
2804 if (list_empty(&next->upper))
2805 break;
2806
2807 edge = list_entry(next->upper.next,
2808 struct backref_edge, list[LOWER]);
2809 edges[index++] = edge;
2810 next = edge->node[UPPER];
2811 }
2812 next = walk_down_backref(edges, &index);
2813 }
2814 }
2815
2816 static int tree_block_processed(u64 bytenr, u32 blocksize,
2817 struct reloc_control *rc)
2818 {
2819 if (test_range_bit(&rc->processed_blocks, bytenr,
2820 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2821 return 1;
2822 return 0;
2823 }
2824
2825 static int get_tree_block_key(struct reloc_control *rc,
2826 struct tree_block *block)
2827 {
2828 struct extent_buffer *eb;
2829
2830 BUG_ON(block->key_ready);
2831 eb = read_tree_block(rc->extent_root, block->bytenr,
2832 block->key.objectid, block->key.offset);
2833 if (!eb || !extent_buffer_uptodate(eb)) {
2834 free_extent_buffer(eb);
2835 return -EIO;
2836 }
2837 WARN_ON(btrfs_header_level(eb) != block->level);
2838 if (block->level == 0)
2839 btrfs_item_key_to_cpu(eb, &block->key, 0);
2840 else
2841 btrfs_node_key_to_cpu(eb, &block->key, 0);
2842 free_extent_buffer(eb);
2843 block->key_ready = 1;
2844 return 0;
2845 }
2846
2847 static int reada_tree_block(struct reloc_control *rc,
2848 struct tree_block *block)
2849 {
2850 BUG_ON(block->key_ready);
2851 if (block->key.type == BTRFS_METADATA_ITEM_KEY)
2852 readahead_tree_block(rc->extent_root, block->bytenr,
2853 block->key.objectid,
2854 rc->extent_root->leafsize);
2855 else
2856 readahead_tree_block(rc->extent_root, block->bytenr,
2857 block->key.objectid, block->key.offset);
2858 return 0;
2859 }
2860
2861 /*
2862 * helper function to relocate a tree block
2863 */
2864 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2865 struct reloc_control *rc,
2866 struct backref_node *node,
2867 struct btrfs_key *key,
2868 struct btrfs_path *path)
2869 {
2870 struct btrfs_root *root;
2871 int release = 0;
2872 int ret = 0;
2873
2874 if (!node)
2875 return 0;
2876
2877 BUG_ON(node->processed);
2878 root = select_one_root(trans, node);
2879 if (root == ERR_PTR(-ENOENT)) {
2880 update_processed_blocks(rc, node);
2881 goto out;
2882 }
2883
2884 if (!root || root->ref_cows) {
2885 ret = reserve_metadata_space(trans, rc, node);
2886 if (ret)
2887 goto out;
2888 release = 1;
2889 }
2890
2891 if (root) {
2892 if (root->ref_cows) {
2893 BUG_ON(node->new_bytenr);
2894 BUG_ON(!list_empty(&node->list));
2895 btrfs_record_root_in_trans(trans, root);
2896 root = root->reloc_root;
2897 node->new_bytenr = root->node->start;
2898 node->root = root;
2899 list_add_tail(&node->list, &rc->backref_cache.changed);
2900 } else {
2901 path->lowest_level = node->level;
2902 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2903 btrfs_release_path(path);
2904 if (ret > 0)
2905 ret = 0;
2906 }
2907 if (!ret)
2908 update_processed_blocks(rc, node);
2909 } else {
2910 ret = do_relocation(trans, rc, node, key, path, 1);
2911 }
2912 out:
2913 if (ret || node->level == 0 || node->cowonly) {
2914 if (release)
2915 release_metadata_space(rc, node);
2916 remove_backref_node(&rc->backref_cache, node);
2917 }
2918 return ret;
2919 }
2920
2921 /*
2922 * relocate a list of blocks
2923 */
2924 static noinline_for_stack
2925 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2926 struct reloc_control *rc, struct rb_root *blocks)
2927 {
2928 struct backref_node *node;
2929 struct btrfs_path *path;
2930 struct tree_block *block;
2931 struct rb_node *rb_node;
2932 int ret;
2933 int err = 0;
2934
2935 path = btrfs_alloc_path();
2936 if (!path) {
2937 err = -ENOMEM;
2938 goto out_free_blocks;
2939 }
2940
2941 rb_node = rb_first(blocks);
2942 while (rb_node) {
2943 block = rb_entry(rb_node, struct tree_block, rb_node);
2944 if (!block->key_ready)
2945 reada_tree_block(rc, block);
2946 rb_node = rb_next(rb_node);
2947 }
2948
2949 rb_node = rb_first(blocks);
2950 while (rb_node) {
2951 block = rb_entry(rb_node, struct tree_block, rb_node);
2952 if (!block->key_ready) {
2953 err = get_tree_block_key(rc, block);
2954 if (err)
2955 goto out_free_path;
2956 }
2957 rb_node = rb_next(rb_node);
2958 }
2959
2960 rb_node = rb_first(blocks);
2961 while (rb_node) {
2962 block = rb_entry(rb_node, struct tree_block, rb_node);
2963
2964 node = build_backref_tree(rc, &block->key,
2965 block->level, block->bytenr);
2966 if (IS_ERR(node)) {
2967 err = PTR_ERR(node);
2968 goto out;
2969 }
2970
2971 ret = relocate_tree_block(trans, rc, node, &block->key,
2972 path);
2973 if (ret < 0) {
2974 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2975 err = ret;
2976 goto out;
2977 }
2978 rb_node = rb_next(rb_node);
2979 }
2980 out:
2981 err = finish_pending_nodes(trans, rc, path, err);
2982
2983 out_free_path:
2984 btrfs_free_path(path);
2985 out_free_blocks:
2986 free_block_list(blocks);
2987 return err;
2988 }
2989
2990 static noinline_for_stack
2991 int prealloc_file_extent_cluster(struct inode *inode,
2992 struct file_extent_cluster *cluster)
2993 {
2994 u64 alloc_hint = 0;
2995 u64 start;
2996 u64 end;
2997 u64 offset = BTRFS_I(inode)->index_cnt;
2998 u64 num_bytes;
2999 int nr = 0;
3000 int ret = 0;
3001
3002 BUG_ON(cluster->start != cluster->boundary[0]);
3003 mutex_lock(&inode->i_mutex);
3004
3005 ret = btrfs_check_data_free_space(inode, cluster->end +
3006 1 - cluster->start);
3007 if (ret)
3008 goto out;
3009
3010 while (nr < cluster->nr) {
3011 start = cluster->boundary[nr] - offset;
3012 if (nr + 1 < cluster->nr)
3013 end = cluster->boundary[nr + 1] - 1 - offset;
3014 else
3015 end = cluster->end - offset;
3016
3017 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3018 num_bytes = end + 1 - start;
3019 ret = btrfs_prealloc_file_range(inode, 0, start,
3020 num_bytes, num_bytes,
3021 end + 1, &alloc_hint);
3022 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3023 if (ret)
3024 break;
3025 nr++;
3026 }
3027 btrfs_free_reserved_data_space(inode, cluster->end +
3028 1 - cluster->start);
3029 out:
3030 mutex_unlock(&inode->i_mutex);
3031 return ret;
3032 }
3033
3034 static noinline_for_stack
3035 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3036 u64 block_start)
3037 {
3038 struct btrfs_root *root = BTRFS_I(inode)->root;
3039 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3040 struct extent_map *em;
3041 int ret = 0;
3042
3043 em = alloc_extent_map();
3044 if (!em)
3045 return -ENOMEM;
3046
3047 em->start = start;
3048 em->len = end + 1 - start;
3049 em->block_len = em->len;
3050 em->block_start = block_start;
3051 em->bdev = root->fs_info->fs_devices->latest_bdev;
3052 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3053
3054 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3055 while (1) {
3056 write_lock(&em_tree->lock);
3057 ret = add_extent_mapping(em_tree, em, 0);
3058 write_unlock(&em_tree->lock);
3059 if (ret != -EEXIST) {
3060 free_extent_map(em);
3061 break;
3062 }
3063 btrfs_drop_extent_cache(inode, start, end, 0);
3064 }
3065 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3066 return ret;
3067 }
3068
3069 static int relocate_file_extent_cluster(struct inode *inode,
3070 struct file_extent_cluster *cluster)
3071 {
3072 u64 page_start;
3073 u64 page_end;
3074 u64 offset = BTRFS_I(inode)->index_cnt;
3075 unsigned long index;
3076 unsigned long last_index;
3077 struct page *page;
3078 struct file_ra_state *ra;
3079 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3080 int nr = 0;
3081 int ret = 0;
3082
3083 if (!cluster->nr)
3084 return 0;
3085
3086 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3087 if (!ra)
3088 return -ENOMEM;
3089
3090 ret = prealloc_file_extent_cluster(inode, cluster);
3091 if (ret)
3092 goto out;
3093
3094 file_ra_state_init(ra, inode->i_mapping);
3095
3096 ret = setup_extent_mapping(inode, cluster->start - offset,
3097 cluster->end - offset, cluster->start);
3098 if (ret)
3099 goto out;
3100
3101 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
3102 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
3103 while (index <= last_index) {
3104 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
3105 if (ret)
3106 goto out;
3107
3108 page = find_lock_page(inode->i_mapping, index);
3109 if (!page) {
3110 page_cache_sync_readahead(inode->i_mapping,
3111 ra, NULL, index,
3112 last_index + 1 - index);
3113 page = find_or_create_page(inode->i_mapping, index,
3114 mask);
3115 if (!page) {
3116 btrfs_delalloc_release_metadata(inode,
3117 PAGE_CACHE_SIZE);
3118 ret = -ENOMEM;
3119 goto out;
3120 }
3121 }
3122
3123 if (PageReadahead(page)) {
3124 page_cache_async_readahead(inode->i_mapping,
3125 ra, NULL, page, index,
3126 last_index + 1 - index);
3127 }
3128
3129 if (!PageUptodate(page)) {
3130 btrfs_readpage(NULL, page);
3131 lock_page(page);
3132 if (!PageUptodate(page)) {
3133 unlock_page(page);
3134 page_cache_release(page);
3135 btrfs_delalloc_release_metadata(inode,
3136 PAGE_CACHE_SIZE);
3137 ret = -EIO;
3138 goto out;
3139 }
3140 }
3141
3142 page_start = page_offset(page);
3143 page_end = page_start + PAGE_CACHE_SIZE - 1;
3144
3145 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3146
3147 set_page_extent_mapped(page);
3148
3149 if (nr < cluster->nr &&
3150 page_start + offset == cluster->boundary[nr]) {
3151 set_extent_bits(&BTRFS_I(inode)->io_tree,
3152 page_start, page_end,
3153 EXTENT_BOUNDARY, GFP_NOFS);
3154 nr++;
3155 }
3156
3157 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3158 set_page_dirty(page);
3159
3160 unlock_extent(&BTRFS_I(inode)->io_tree,
3161 page_start, page_end);
3162 unlock_page(page);
3163 page_cache_release(page);
3164
3165 index++;
3166 balance_dirty_pages_ratelimited(inode->i_mapping);
3167 btrfs_throttle(BTRFS_I(inode)->root);
3168 }
3169 WARN_ON(nr != cluster->nr);
3170 out:
3171 kfree(ra);
3172 return ret;
3173 }
3174
3175 static noinline_for_stack
3176 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3177 struct file_extent_cluster *cluster)
3178 {
3179 int ret;
3180
3181 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3182 ret = relocate_file_extent_cluster(inode, cluster);
3183 if (ret)
3184 return ret;
3185 cluster->nr = 0;
3186 }
3187
3188 if (!cluster->nr)
3189 cluster->start = extent_key->objectid;
3190 else
3191 BUG_ON(cluster->nr >= MAX_EXTENTS);
3192 cluster->end = extent_key->objectid + extent_key->offset - 1;
3193 cluster->boundary[cluster->nr] = extent_key->objectid;
3194 cluster->nr++;
3195
3196 if (cluster->nr >= MAX_EXTENTS) {
3197 ret = relocate_file_extent_cluster(inode, cluster);
3198 if (ret)
3199 return ret;
3200 cluster->nr = 0;
3201 }
3202 return 0;
3203 }
3204
3205 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3206 static int get_ref_objectid_v0(struct reloc_control *rc,
3207 struct btrfs_path *path,
3208 struct btrfs_key *extent_key,
3209 u64 *ref_objectid, int *path_change)
3210 {
3211 struct btrfs_key key;
3212 struct extent_buffer *leaf;
3213 struct btrfs_extent_ref_v0 *ref0;
3214 int ret;
3215 int slot;
3216
3217 leaf = path->nodes[0];
3218 slot = path->slots[0];
3219 while (1) {
3220 if (slot >= btrfs_header_nritems(leaf)) {
3221 ret = btrfs_next_leaf(rc->extent_root, path);
3222 if (ret < 0)
3223 return ret;
3224 BUG_ON(ret > 0);
3225 leaf = path->nodes[0];
3226 slot = path->slots[0];
3227 if (path_change)
3228 *path_change = 1;
3229 }
3230 btrfs_item_key_to_cpu(leaf, &key, slot);
3231 if (key.objectid != extent_key->objectid)
3232 return -ENOENT;
3233
3234 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3235 slot++;
3236 continue;
3237 }
3238 ref0 = btrfs_item_ptr(leaf, slot,
3239 struct btrfs_extent_ref_v0);
3240 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3241 break;
3242 }
3243 return 0;
3244 }
3245 #endif
3246
3247 /*
3248 * helper to add a tree block to the list.
3249 * the major work is getting the generation and level of the block
3250 */
3251 static int add_tree_block(struct reloc_control *rc,
3252 struct btrfs_key *extent_key,
3253 struct btrfs_path *path,
3254 struct rb_root *blocks)
3255 {
3256 struct extent_buffer *eb;
3257 struct btrfs_extent_item *ei;
3258 struct btrfs_tree_block_info *bi;
3259 struct tree_block *block;
3260 struct rb_node *rb_node;
3261 u32 item_size;
3262 int level = -1;
3263 int generation;
3264
3265 eb = path->nodes[0];
3266 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3267
3268 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3269 item_size >= sizeof(*ei) + sizeof(*bi)) {
3270 ei = btrfs_item_ptr(eb, path->slots[0],
3271 struct btrfs_extent_item);
3272 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3273 bi = (struct btrfs_tree_block_info *)(ei + 1);
3274 level = btrfs_tree_block_level(eb, bi);
3275 } else {
3276 level = (int)extent_key->offset;
3277 }
3278 generation = btrfs_extent_generation(eb, ei);
3279 } else {
3280 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3281 u64 ref_owner;
3282 int ret;
3283
3284 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3285 ret = get_ref_objectid_v0(rc, path, extent_key,
3286 &ref_owner, NULL);
3287 if (ret < 0)
3288 return ret;
3289 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3290 level = (int)ref_owner;
3291 /* FIXME: get real generation */
3292 generation = 0;
3293 #else
3294 BUG();
3295 #endif
3296 }
3297
3298 btrfs_release_path(path);
3299
3300 BUG_ON(level == -1);
3301
3302 block = kmalloc(sizeof(*block), GFP_NOFS);
3303 if (!block)
3304 return -ENOMEM;
3305
3306 block->bytenr = extent_key->objectid;
3307 block->key.objectid = rc->extent_root->leafsize;
3308 block->key.offset = generation;
3309 block->level = level;
3310 block->key_ready = 0;
3311
3312 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3313 if (rb_node)
3314 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3315
3316 return 0;
3317 }
3318
3319 /*
3320 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3321 */
3322 static int __add_tree_block(struct reloc_control *rc,
3323 u64 bytenr, u32 blocksize,
3324 struct rb_root *blocks)
3325 {
3326 struct btrfs_path *path;
3327 struct btrfs_key key;
3328 int ret;
3329 bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info,
3330 SKINNY_METADATA);
3331
3332 if (tree_block_processed(bytenr, blocksize, rc))
3333 return 0;
3334
3335 if (tree_search(blocks, bytenr))
3336 return 0;
3337
3338 path = btrfs_alloc_path();
3339 if (!path)
3340 return -ENOMEM;
3341 again:
3342 key.objectid = bytenr;
3343 if (skinny) {
3344 key.type = BTRFS_METADATA_ITEM_KEY;
3345 key.offset = (u64)-1;
3346 } else {
3347 key.type = BTRFS_EXTENT_ITEM_KEY;
3348 key.offset = blocksize;
3349 }
3350
3351 path->search_commit_root = 1;
3352 path->skip_locking = 1;
3353 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3354 if (ret < 0)
3355 goto out;
3356
3357 if (ret > 0 && skinny) {
3358 if (path->slots[0]) {
3359 path->slots[0]--;
3360 btrfs_item_key_to_cpu(path->nodes[0], &key,
3361 path->slots[0]);
3362 if (key.objectid == bytenr &&
3363 (key.type == BTRFS_METADATA_ITEM_KEY ||
3364 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3365 key.offset == blocksize)))
3366 ret = 0;
3367 }
3368
3369 if (ret) {
3370 skinny = false;
3371 btrfs_release_path(path);
3372 goto again;
3373 }
3374 }
3375 BUG_ON(ret);
3376
3377 ret = add_tree_block(rc, &key, path, blocks);
3378 out:
3379 btrfs_free_path(path);
3380 return ret;
3381 }
3382
3383 /*
3384 * helper to check if the block use full backrefs for pointers in it
3385 */
3386 static int block_use_full_backref(struct reloc_control *rc,
3387 struct extent_buffer *eb)
3388 {
3389 u64 flags;
3390 int ret;
3391
3392 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3393 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3394 return 1;
3395
3396 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3397 eb->start, btrfs_header_level(eb), 1,
3398 NULL, &flags);
3399 BUG_ON(ret);
3400
3401 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3402 ret = 1;
3403 else
3404 ret = 0;
3405 return ret;
3406 }
3407
3408 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3409 struct inode *inode, u64 ino)
3410 {
3411 struct btrfs_key key;
3412 struct btrfs_path *path;
3413 struct btrfs_root *root = fs_info->tree_root;
3414 struct btrfs_trans_handle *trans;
3415 int ret = 0;
3416
3417 if (inode)
3418 goto truncate;
3419
3420 key.objectid = ino;
3421 key.type = BTRFS_INODE_ITEM_KEY;
3422 key.offset = 0;
3423
3424 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3425 if (IS_ERR(inode) || is_bad_inode(inode)) {
3426 if (!IS_ERR(inode))
3427 iput(inode);
3428 return -ENOENT;
3429 }
3430
3431 truncate:
3432 ret = btrfs_check_trunc_cache_free_space(root,
3433 &fs_info->global_block_rsv);
3434 if (ret)
3435 goto out;
3436
3437 path = btrfs_alloc_path();
3438 if (!path) {
3439 ret = -ENOMEM;
3440 goto out;
3441 }
3442
3443 trans = btrfs_join_transaction(root);
3444 if (IS_ERR(trans)) {
3445 btrfs_free_path(path);
3446 ret = PTR_ERR(trans);
3447 goto out;
3448 }
3449
3450 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
3451
3452 btrfs_free_path(path);
3453 btrfs_end_transaction(trans, root);
3454 btrfs_btree_balance_dirty(root);
3455 out:
3456 iput(inode);
3457 return ret;
3458 }
3459
3460 /*
3461 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3462 * this function scans fs tree to find blocks reference the data extent
3463 */
3464 static int find_data_references(struct reloc_control *rc,
3465 struct btrfs_key *extent_key,
3466 struct extent_buffer *leaf,
3467 struct btrfs_extent_data_ref *ref,
3468 struct rb_root *blocks)
3469 {
3470 struct btrfs_path *path;
3471 struct tree_block *block;
3472 struct btrfs_root *root;
3473 struct btrfs_file_extent_item *fi;
3474 struct rb_node *rb_node;
3475 struct btrfs_key key;
3476 u64 ref_root;
3477 u64 ref_objectid;
3478 u64 ref_offset;
3479 u32 ref_count;
3480 u32 nritems;
3481 int err = 0;
3482 int added = 0;
3483 int counted;
3484 int ret;
3485
3486 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3487 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3488 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3489 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3490
3491 /*
3492 * This is an extent belonging to the free space cache, lets just delete
3493 * it and redo the search.
3494 */
3495 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3496 ret = delete_block_group_cache(rc->extent_root->fs_info,
3497 NULL, ref_objectid);
3498 if (ret != -ENOENT)
3499 return ret;
3500 ret = 0;
3501 }
3502
3503 path = btrfs_alloc_path();
3504 if (!path)
3505 return -ENOMEM;
3506 path->reada = 1;
3507
3508 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3509 if (IS_ERR(root)) {
3510 err = PTR_ERR(root);
3511 goto out;
3512 }
3513
3514 key.objectid = ref_objectid;
3515 key.type = BTRFS_EXTENT_DATA_KEY;
3516 if (ref_offset > ((u64)-1 << 32))
3517 key.offset = 0;
3518 else
3519 key.offset = ref_offset;
3520
3521 path->search_commit_root = 1;
3522 path->skip_locking = 1;
3523 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3524 if (ret < 0) {
3525 err = ret;
3526 goto out;
3527 }
3528
3529 leaf = path->nodes[0];
3530 nritems = btrfs_header_nritems(leaf);
3531 /*
3532 * the references in tree blocks that use full backrefs
3533 * are not counted in
3534 */
3535 if (block_use_full_backref(rc, leaf))
3536 counted = 0;
3537 else
3538 counted = 1;
3539 rb_node = tree_search(blocks, leaf->start);
3540 if (rb_node) {
3541 if (counted)
3542 added = 1;
3543 else
3544 path->slots[0] = nritems;
3545 }
3546
3547 while (ref_count > 0) {
3548 while (path->slots[0] >= nritems) {
3549 ret = btrfs_next_leaf(root, path);
3550 if (ret < 0) {
3551 err = ret;
3552 goto out;
3553 }
3554 if (ret > 0) {
3555 WARN_ON(1);
3556 goto out;
3557 }
3558
3559 leaf = path->nodes[0];
3560 nritems = btrfs_header_nritems(leaf);
3561 added = 0;
3562
3563 if (block_use_full_backref(rc, leaf))
3564 counted = 0;
3565 else
3566 counted = 1;
3567 rb_node = tree_search(blocks, leaf->start);
3568 if (rb_node) {
3569 if (counted)
3570 added = 1;
3571 else
3572 path->slots[0] = nritems;
3573 }
3574 }
3575
3576 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3577 if (key.objectid != ref_objectid ||
3578 key.type != BTRFS_EXTENT_DATA_KEY) {
3579 WARN_ON(1);
3580 break;
3581 }
3582
3583 fi = btrfs_item_ptr(leaf, path->slots[0],
3584 struct btrfs_file_extent_item);
3585
3586 if (btrfs_file_extent_type(leaf, fi) ==
3587 BTRFS_FILE_EXTENT_INLINE)
3588 goto next;
3589
3590 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3591 extent_key->objectid)
3592 goto next;
3593
3594 key.offset -= btrfs_file_extent_offset(leaf, fi);
3595 if (key.offset != ref_offset)
3596 goto next;
3597
3598 if (counted)
3599 ref_count--;
3600 if (added)
3601 goto next;
3602
3603 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3604 block = kmalloc(sizeof(*block), GFP_NOFS);
3605 if (!block) {
3606 err = -ENOMEM;
3607 break;
3608 }
3609 block->bytenr = leaf->start;
3610 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3611 block->level = 0;
3612 block->key_ready = 1;
3613 rb_node = tree_insert(blocks, block->bytenr,
3614 &block->rb_node);
3615 if (rb_node)
3616 backref_tree_panic(rb_node, -EEXIST,
3617 block->bytenr);
3618 }
3619 if (counted)
3620 added = 1;
3621 else
3622 path->slots[0] = nritems;
3623 next:
3624 path->slots[0]++;
3625
3626 }
3627 out:
3628 btrfs_free_path(path);
3629 return err;
3630 }
3631
3632 /*
3633 * helper to find all tree blocks that reference a given data extent
3634 */
3635 static noinline_for_stack
3636 int add_data_references(struct reloc_control *rc,
3637 struct btrfs_key *extent_key,
3638 struct btrfs_path *path,
3639 struct rb_root *blocks)
3640 {
3641 struct btrfs_key key;
3642 struct extent_buffer *eb;
3643 struct btrfs_extent_data_ref *dref;
3644 struct btrfs_extent_inline_ref *iref;
3645 unsigned long ptr;
3646 unsigned long end;
3647 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3648 int ret = 0;
3649 int err = 0;
3650
3651 eb = path->nodes[0];
3652 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3653 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3654 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3655 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3656 ptr = end;
3657 else
3658 #endif
3659 ptr += sizeof(struct btrfs_extent_item);
3660
3661 while (ptr < end) {
3662 iref = (struct btrfs_extent_inline_ref *)ptr;
3663 key.type = btrfs_extent_inline_ref_type(eb, iref);
3664 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3665 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3666 ret = __add_tree_block(rc, key.offset, blocksize,
3667 blocks);
3668 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3669 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3670 ret = find_data_references(rc, extent_key,
3671 eb, dref, blocks);
3672 } else {
3673 BUG();
3674 }
3675 if (ret) {
3676 err = ret;
3677 goto out;
3678 }
3679 ptr += btrfs_extent_inline_ref_size(key.type);
3680 }
3681 WARN_ON(ptr > end);
3682
3683 while (1) {
3684 cond_resched();
3685 eb = path->nodes[0];
3686 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3687 ret = btrfs_next_leaf(rc->extent_root, path);
3688 if (ret < 0) {
3689 err = ret;
3690 break;
3691 }
3692 if (ret > 0)
3693 break;
3694 eb = path->nodes[0];
3695 }
3696
3697 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3698 if (key.objectid != extent_key->objectid)
3699 break;
3700
3701 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3702 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3703 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3704 #else
3705 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3706 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3707 #endif
3708 ret = __add_tree_block(rc, key.offset, blocksize,
3709 blocks);
3710 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3711 dref = btrfs_item_ptr(eb, path->slots[0],
3712 struct btrfs_extent_data_ref);
3713 ret = find_data_references(rc, extent_key,
3714 eb, dref, blocks);
3715 } else {
3716 ret = 0;
3717 }
3718 if (ret) {
3719 err = ret;
3720 break;
3721 }
3722 path->slots[0]++;
3723 }
3724 out:
3725 btrfs_release_path(path);
3726 if (err)
3727 free_block_list(blocks);
3728 return err;
3729 }
3730
3731 /*
3732 * helper to find next unprocessed extent
3733 */
3734 static noinline_for_stack
3735 int find_next_extent(struct btrfs_trans_handle *trans,
3736 struct reloc_control *rc, struct btrfs_path *path,
3737 struct btrfs_key *extent_key)
3738 {
3739 struct btrfs_key key;
3740 struct extent_buffer *leaf;
3741 u64 start, end, last;
3742 int ret;
3743
3744 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3745 while (1) {
3746 cond_resched();
3747 if (rc->search_start >= last) {
3748 ret = 1;
3749 break;
3750 }
3751
3752 key.objectid = rc->search_start;
3753 key.type = BTRFS_EXTENT_ITEM_KEY;
3754 key.offset = 0;
3755
3756 path->search_commit_root = 1;
3757 path->skip_locking = 1;
3758 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3759 0, 0);
3760 if (ret < 0)
3761 break;
3762 next:
3763 leaf = path->nodes[0];
3764 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3765 ret = btrfs_next_leaf(rc->extent_root, path);
3766 if (ret != 0)
3767 break;
3768 leaf = path->nodes[0];
3769 }
3770
3771 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3772 if (key.objectid >= last) {
3773 ret = 1;
3774 break;
3775 }
3776
3777 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3778 key.type != BTRFS_METADATA_ITEM_KEY) {
3779 path->slots[0]++;
3780 goto next;
3781 }
3782
3783 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3784 key.objectid + key.offset <= rc->search_start) {
3785 path->slots[0]++;
3786 goto next;
3787 }
3788
3789 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3790 key.objectid + rc->extent_root->leafsize <=
3791 rc->search_start) {
3792 path->slots[0]++;
3793 goto next;
3794 }
3795
3796 ret = find_first_extent_bit(&rc->processed_blocks,
3797 key.objectid, &start, &end,
3798 EXTENT_DIRTY, NULL);
3799
3800 if (ret == 0 && start <= key.objectid) {
3801 btrfs_release_path(path);
3802 rc->search_start = end + 1;
3803 } else {
3804 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3805 rc->search_start = key.objectid + key.offset;
3806 else
3807 rc->search_start = key.objectid +
3808 rc->extent_root->leafsize;
3809 memcpy(extent_key, &key, sizeof(key));
3810 return 0;
3811 }
3812 }
3813 btrfs_release_path(path);
3814 return ret;
3815 }
3816
3817 static void set_reloc_control(struct reloc_control *rc)
3818 {
3819 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3820
3821 mutex_lock(&fs_info->reloc_mutex);
3822 fs_info->reloc_ctl = rc;
3823 mutex_unlock(&fs_info->reloc_mutex);
3824 }
3825
3826 static void unset_reloc_control(struct reloc_control *rc)
3827 {
3828 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3829
3830 mutex_lock(&fs_info->reloc_mutex);
3831 fs_info->reloc_ctl = NULL;
3832 mutex_unlock(&fs_info->reloc_mutex);
3833 }
3834
3835 static int check_extent_flags(u64 flags)
3836 {
3837 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3838 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3839 return 1;
3840 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3841 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3842 return 1;
3843 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3844 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3845 return 1;
3846 return 0;
3847 }
3848
3849 static noinline_for_stack
3850 int prepare_to_relocate(struct reloc_control *rc)
3851 {
3852 struct btrfs_trans_handle *trans;
3853 int ret;
3854
3855 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3856 BTRFS_BLOCK_RSV_TEMP);
3857 if (!rc->block_rsv)
3858 return -ENOMEM;
3859
3860 /*
3861 * reserve some space for creating reloc trees.
3862 * btrfs_init_reloc_root will use them when there
3863 * is no reservation in transaction handle.
3864 */
3865 ret = btrfs_block_rsv_add(rc->extent_root, rc->block_rsv,
3866 rc->extent_root->nodesize * 256,
3867 BTRFS_RESERVE_FLUSH_ALL);
3868 if (ret)
3869 return ret;
3870
3871 memset(&rc->cluster, 0, sizeof(rc->cluster));
3872 rc->search_start = rc->block_group->key.objectid;
3873 rc->extents_found = 0;
3874 rc->nodes_relocated = 0;
3875 rc->merging_rsv_size = 0;
3876
3877 rc->create_reloc_tree = 1;
3878 set_reloc_control(rc);
3879
3880 trans = btrfs_join_transaction(rc->extent_root);
3881 if (IS_ERR(trans)) {
3882 unset_reloc_control(rc);
3883 /*
3884 * extent tree is not a ref_cow tree and has no reloc_root to
3885 * cleanup. And callers are responsible to free the above
3886 * block rsv.
3887 */
3888 return PTR_ERR(trans);
3889 }
3890 btrfs_commit_transaction(trans, rc->extent_root);
3891 return 0;
3892 }
3893
3894 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3895 {
3896 struct rb_root blocks = RB_ROOT;
3897 struct btrfs_key key;
3898 struct btrfs_trans_handle *trans = NULL;
3899 struct btrfs_path *path;
3900 struct btrfs_extent_item *ei;
3901 u64 flags;
3902 u32 item_size;
3903 int ret;
3904 int err = 0;
3905 int progress = 0;
3906
3907 path = btrfs_alloc_path();
3908 if (!path)
3909 return -ENOMEM;
3910 path->reada = 1;
3911
3912 ret = prepare_to_relocate(rc);
3913 if (ret) {
3914 err = ret;
3915 goto out_free;
3916 }
3917
3918 while (1) {
3919 progress++;
3920 trans = btrfs_start_transaction(rc->extent_root, 0);
3921 if (IS_ERR(trans)) {
3922 err = PTR_ERR(trans);
3923 trans = NULL;
3924 break;
3925 }
3926 restart:
3927 if (update_backref_cache(trans, &rc->backref_cache)) {
3928 btrfs_end_transaction(trans, rc->extent_root);
3929 continue;
3930 }
3931
3932 ret = find_next_extent(trans, rc, path, &key);
3933 if (ret < 0)
3934 err = ret;
3935 if (ret != 0)
3936 break;
3937
3938 rc->extents_found++;
3939
3940 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3941 struct btrfs_extent_item);
3942 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3943 if (item_size >= sizeof(*ei)) {
3944 flags = btrfs_extent_flags(path->nodes[0], ei);
3945 ret = check_extent_flags(flags);
3946 BUG_ON(ret);
3947
3948 } else {
3949 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3950 u64 ref_owner;
3951 int path_change = 0;
3952
3953 BUG_ON(item_size !=
3954 sizeof(struct btrfs_extent_item_v0));
3955 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3956 &path_change);
3957 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3958 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3959 else
3960 flags = BTRFS_EXTENT_FLAG_DATA;
3961
3962 if (path_change) {
3963 btrfs_release_path(path);
3964
3965 path->search_commit_root = 1;
3966 path->skip_locking = 1;
3967 ret = btrfs_search_slot(NULL, rc->extent_root,
3968 &key, path, 0, 0);
3969 if (ret < 0) {
3970 err = ret;
3971 break;
3972 }
3973 BUG_ON(ret > 0);
3974 }
3975 #else
3976 BUG();
3977 #endif
3978 }
3979
3980 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3981 ret = add_tree_block(rc, &key, path, &blocks);
3982 } else if (rc->stage == UPDATE_DATA_PTRS &&
3983 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3984 ret = add_data_references(rc, &key, path, &blocks);
3985 } else {
3986 btrfs_release_path(path);
3987 ret = 0;
3988 }
3989 if (ret < 0) {
3990 err = ret;
3991 break;
3992 }
3993
3994 if (!RB_EMPTY_ROOT(&blocks)) {
3995 ret = relocate_tree_blocks(trans, rc, &blocks);
3996 if (ret < 0) {
3997 if (ret != -EAGAIN) {
3998 err = ret;
3999 break;
4000 }
4001 rc->extents_found--;
4002 rc->search_start = key.objectid;
4003 }
4004 }
4005
4006 ret = btrfs_block_rsv_check(rc->extent_root, rc->block_rsv, 5);
4007 if (ret < 0) {
4008 if (ret != -ENOSPC) {
4009 err = ret;
4010 WARN_ON(1);
4011 break;
4012 }
4013 rc->commit_transaction = 1;
4014 }
4015
4016 if (rc->commit_transaction) {
4017 rc->commit_transaction = 0;
4018 ret = btrfs_commit_transaction(trans, rc->extent_root);
4019 BUG_ON(ret);
4020 } else {
4021 btrfs_end_transaction_throttle(trans, rc->extent_root);
4022 btrfs_btree_balance_dirty(rc->extent_root);
4023 }
4024 trans = NULL;
4025
4026 if (rc->stage == MOVE_DATA_EXTENTS &&
4027 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4028 rc->found_file_extent = 1;
4029 ret = relocate_data_extent(rc->data_inode,
4030 &key, &rc->cluster);
4031 if (ret < 0) {
4032 err = ret;
4033 break;
4034 }
4035 }
4036 }
4037 if (trans && progress && err == -ENOSPC) {
4038 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
4039 rc->block_group->flags);
4040 if (ret == 0) {
4041 err = 0;
4042 progress = 0;
4043 goto restart;
4044 }
4045 }
4046
4047 btrfs_release_path(path);
4048 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
4049 GFP_NOFS);
4050
4051 if (trans) {
4052 btrfs_end_transaction_throttle(trans, rc->extent_root);
4053 btrfs_btree_balance_dirty(rc->extent_root);
4054 }
4055
4056 if (!err) {
4057 ret = relocate_file_extent_cluster(rc->data_inode,
4058 &rc->cluster);
4059 if (ret < 0)
4060 err = ret;
4061 }
4062
4063 rc->create_reloc_tree = 0;
4064 set_reloc_control(rc);
4065
4066 backref_cache_cleanup(&rc->backref_cache);
4067 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4068
4069 err = prepare_to_merge(rc, err);
4070
4071 merge_reloc_roots(rc);
4072
4073 rc->merge_reloc_tree = 0;
4074 unset_reloc_control(rc);
4075 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4076
4077 /* get rid of pinned extents */
4078 trans = btrfs_join_transaction(rc->extent_root);
4079 if (IS_ERR(trans))
4080 err = PTR_ERR(trans);
4081 else
4082 btrfs_commit_transaction(trans, rc->extent_root);
4083 out_free:
4084 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
4085 btrfs_free_path(path);
4086 return err;
4087 }
4088
4089 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4090 struct btrfs_root *root, u64 objectid)
4091 {
4092 struct btrfs_path *path;
4093 struct btrfs_inode_item *item;
4094 struct extent_buffer *leaf;
4095 int ret;
4096
4097 path = btrfs_alloc_path();
4098 if (!path)
4099 return -ENOMEM;
4100
4101 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4102 if (ret)
4103 goto out;
4104
4105 leaf = path->nodes[0];
4106 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4107 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4108 btrfs_set_inode_generation(leaf, item, 1);
4109 btrfs_set_inode_size(leaf, item, 0);
4110 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4111 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4112 BTRFS_INODE_PREALLOC);
4113 btrfs_mark_buffer_dirty(leaf);
4114 btrfs_release_path(path);
4115 out:
4116 btrfs_free_path(path);
4117 return ret;
4118 }
4119
4120 /*
4121 * helper to create inode for data relocation.
4122 * the inode is in data relocation tree and its link count is 0
4123 */
4124 static noinline_for_stack
4125 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4126 struct btrfs_block_group_cache *group)
4127 {
4128 struct inode *inode = NULL;
4129 struct btrfs_trans_handle *trans;
4130 struct btrfs_root *root;
4131 struct btrfs_key key;
4132 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
4133 int err = 0;
4134
4135 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4136 if (IS_ERR(root))
4137 return ERR_CAST(root);
4138
4139 trans = btrfs_start_transaction(root, 6);
4140 if (IS_ERR(trans))
4141 return ERR_CAST(trans);
4142
4143 err = btrfs_find_free_objectid(root, &objectid);
4144 if (err)
4145 goto out;
4146
4147 err = __insert_orphan_inode(trans, root, objectid);
4148 BUG_ON(err);
4149
4150 key.objectid = objectid;
4151 key.type = BTRFS_INODE_ITEM_KEY;
4152 key.offset = 0;
4153 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
4154 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4155 BTRFS_I(inode)->index_cnt = group->key.objectid;
4156
4157 err = btrfs_orphan_add(trans, inode);
4158 out:
4159 btrfs_end_transaction(trans, root);
4160 btrfs_btree_balance_dirty(root);
4161 if (err) {
4162 if (inode)
4163 iput(inode);
4164 inode = ERR_PTR(err);
4165 }
4166 return inode;
4167 }
4168
4169 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4170 {
4171 struct reloc_control *rc;
4172
4173 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4174 if (!rc)
4175 return NULL;
4176
4177 INIT_LIST_HEAD(&rc->reloc_roots);
4178 backref_cache_init(&rc->backref_cache);
4179 mapping_tree_init(&rc->reloc_root_tree);
4180 extent_io_tree_init(&rc->processed_blocks,
4181 fs_info->btree_inode->i_mapping);
4182 return rc;
4183 }
4184
4185 /*
4186 * function to relocate all extents in a block group.
4187 */
4188 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4189 {
4190 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4191 struct reloc_control *rc;
4192 struct inode *inode;
4193 struct btrfs_path *path;
4194 int ret;
4195 int rw = 0;
4196 int err = 0;
4197
4198 rc = alloc_reloc_control(fs_info);
4199 if (!rc)
4200 return -ENOMEM;
4201
4202 rc->extent_root = extent_root;
4203
4204 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4205 BUG_ON(!rc->block_group);
4206
4207 if (!rc->block_group->ro) {
4208 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
4209 if (ret) {
4210 err = ret;
4211 goto out;
4212 }
4213 rw = 1;
4214 }
4215
4216 path = btrfs_alloc_path();
4217 if (!path) {
4218 err = -ENOMEM;
4219 goto out;
4220 }
4221
4222 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4223 path);
4224 btrfs_free_path(path);
4225
4226 if (!IS_ERR(inode))
4227 ret = delete_block_group_cache(fs_info, inode, 0);
4228 else
4229 ret = PTR_ERR(inode);
4230
4231 if (ret && ret != -ENOENT) {
4232 err = ret;
4233 goto out;
4234 }
4235
4236 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4237 if (IS_ERR(rc->data_inode)) {
4238 err = PTR_ERR(rc->data_inode);
4239 rc->data_inode = NULL;
4240 goto out;
4241 }
4242
4243 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
4244 rc->block_group->key.objectid, rc->block_group->flags);
4245
4246 ret = btrfs_start_all_delalloc_inodes(fs_info, 0);
4247 if (ret < 0) {
4248 err = ret;
4249 goto out;
4250 }
4251 btrfs_wait_all_ordered_extents(fs_info);
4252
4253 while (1) {
4254 mutex_lock(&fs_info->cleaner_mutex);
4255 ret = relocate_block_group(rc);
4256 mutex_unlock(&fs_info->cleaner_mutex);
4257 if (ret < 0) {
4258 err = ret;
4259 goto out;
4260 }
4261
4262 if (rc->extents_found == 0)
4263 break;
4264
4265 printk(KERN_INFO "btrfs: found %llu extents\n",
4266 rc->extents_found);
4267
4268 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4269 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
4270 invalidate_mapping_pages(rc->data_inode->i_mapping,
4271 0, -1);
4272 rc->stage = UPDATE_DATA_PTRS;
4273 }
4274 }
4275
4276 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
4277 rc->block_group->key.objectid,
4278 rc->block_group->key.objectid +
4279 rc->block_group->key.offset - 1);
4280
4281 WARN_ON(rc->block_group->pinned > 0);
4282 WARN_ON(rc->block_group->reserved > 0);
4283 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4284 out:
4285 if (err && rw)
4286 btrfs_set_block_group_rw(extent_root, rc->block_group);
4287 iput(rc->data_inode);
4288 btrfs_put_block_group(rc->block_group);
4289 kfree(rc);
4290 return err;
4291 }
4292
4293 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4294 {
4295 struct btrfs_trans_handle *trans;
4296 int ret, err;
4297
4298 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4299 if (IS_ERR(trans))
4300 return PTR_ERR(trans);
4301
4302 memset(&root->root_item.drop_progress, 0,
4303 sizeof(root->root_item.drop_progress));
4304 root->root_item.drop_level = 0;
4305 btrfs_set_root_refs(&root->root_item, 0);
4306 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4307 &root->root_key, &root->root_item);
4308
4309 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4310 if (err)
4311 return err;
4312 return ret;
4313 }
4314
4315 /*
4316 * recover relocation interrupted by system crash.
4317 *
4318 * this function resumes merging reloc trees with corresponding fs trees.
4319 * this is important for keeping the sharing of tree blocks
4320 */
4321 int btrfs_recover_relocation(struct btrfs_root *root)
4322 {
4323 LIST_HEAD(reloc_roots);
4324 struct btrfs_key key;
4325 struct btrfs_root *fs_root;
4326 struct btrfs_root *reloc_root;
4327 struct btrfs_path *path;
4328 struct extent_buffer *leaf;
4329 struct reloc_control *rc = NULL;
4330 struct btrfs_trans_handle *trans;
4331 int ret;
4332 int err = 0;
4333
4334 path = btrfs_alloc_path();
4335 if (!path)
4336 return -ENOMEM;
4337 path->reada = -1;
4338
4339 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4340 key.type = BTRFS_ROOT_ITEM_KEY;
4341 key.offset = (u64)-1;
4342
4343 while (1) {
4344 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4345 path, 0, 0);
4346 if (ret < 0) {
4347 err = ret;
4348 goto out;
4349 }
4350 if (ret > 0) {
4351 if (path->slots[0] == 0)
4352 break;
4353 path->slots[0]--;
4354 }
4355 leaf = path->nodes[0];
4356 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4357 btrfs_release_path(path);
4358
4359 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4360 key.type != BTRFS_ROOT_ITEM_KEY)
4361 break;
4362
4363 reloc_root = btrfs_read_fs_root(root, &key);
4364 if (IS_ERR(reloc_root)) {
4365 err = PTR_ERR(reloc_root);
4366 goto out;
4367 }
4368
4369 list_add(&reloc_root->root_list, &reloc_roots);
4370
4371 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4372 fs_root = read_fs_root(root->fs_info,
4373 reloc_root->root_key.offset);
4374 if (IS_ERR(fs_root)) {
4375 ret = PTR_ERR(fs_root);
4376 if (ret != -ENOENT) {
4377 err = ret;
4378 goto out;
4379 }
4380 ret = mark_garbage_root(reloc_root);
4381 if (ret < 0) {
4382 err = ret;
4383 goto out;
4384 }
4385 }
4386 }
4387
4388 if (key.offset == 0)
4389 break;
4390
4391 key.offset--;
4392 }
4393 btrfs_release_path(path);
4394
4395 if (list_empty(&reloc_roots))
4396 goto out;
4397
4398 rc = alloc_reloc_control(root->fs_info);
4399 if (!rc) {
4400 err = -ENOMEM;
4401 goto out;
4402 }
4403
4404 rc->extent_root = root->fs_info->extent_root;
4405
4406 set_reloc_control(rc);
4407
4408 trans = btrfs_join_transaction(rc->extent_root);
4409 if (IS_ERR(trans)) {
4410 unset_reloc_control(rc);
4411 err = PTR_ERR(trans);
4412 goto out_free;
4413 }
4414
4415 rc->merge_reloc_tree = 1;
4416
4417 while (!list_empty(&reloc_roots)) {
4418 reloc_root = list_entry(reloc_roots.next,
4419 struct btrfs_root, root_list);
4420 list_del(&reloc_root->root_list);
4421
4422 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4423 list_add_tail(&reloc_root->root_list,
4424 &rc->reloc_roots);
4425 continue;
4426 }
4427
4428 fs_root = read_fs_root(root->fs_info,
4429 reloc_root->root_key.offset);
4430 if (IS_ERR(fs_root)) {
4431 err = PTR_ERR(fs_root);
4432 goto out_free;
4433 }
4434
4435 err = __add_reloc_root(reloc_root);
4436 BUG_ON(err < 0); /* -ENOMEM or logic error */
4437 fs_root->reloc_root = reloc_root;
4438 }
4439
4440 err = btrfs_commit_transaction(trans, rc->extent_root);
4441 if (err)
4442 goto out_free;
4443
4444 merge_reloc_roots(rc);
4445
4446 unset_reloc_control(rc);
4447
4448 trans = btrfs_join_transaction(rc->extent_root);
4449 if (IS_ERR(trans))
4450 err = PTR_ERR(trans);
4451 else
4452 err = btrfs_commit_transaction(trans, rc->extent_root);
4453 out_free:
4454 kfree(rc);
4455 out:
4456 if (!list_empty(&reloc_roots))
4457 free_reloc_roots(&reloc_roots);
4458
4459 btrfs_free_path(path);
4460
4461 if (err == 0) {
4462 /* cleanup orphan inode in data relocation tree */
4463 fs_root = read_fs_root(root->fs_info,
4464 BTRFS_DATA_RELOC_TREE_OBJECTID);
4465 if (IS_ERR(fs_root))
4466 err = PTR_ERR(fs_root);
4467 else
4468 err = btrfs_orphan_cleanup(fs_root);
4469 }
4470 return err;
4471 }
4472
4473 /*
4474 * helper to add ordered checksum for data relocation.
4475 *
4476 * cloning checksum properly handles the nodatasum extents.
4477 * it also saves CPU time to re-calculate the checksum.
4478 */
4479 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4480 {
4481 struct btrfs_ordered_sum *sums;
4482 struct btrfs_ordered_extent *ordered;
4483 struct btrfs_root *root = BTRFS_I(inode)->root;
4484 int ret;
4485 u64 disk_bytenr;
4486 u64 new_bytenr;
4487 LIST_HEAD(list);
4488
4489 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4490 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4491
4492 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4493 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4494 disk_bytenr + len - 1, &list, 0);
4495 if (ret)
4496 goto out;
4497
4498 while (!list_empty(&list)) {
4499 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4500 list_del_init(&sums->list);
4501
4502 /*
4503 * We need to offset the new_bytenr based on where the csum is.
4504 * We need to do this because we will read in entire prealloc
4505 * extents but we may have written to say the middle of the
4506 * prealloc extent, so we need to make sure the csum goes with
4507 * the right disk offset.
4508 *
4509 * We can do this because the data reloc inode refers strictly
4510 * to the on disk bytes, so we don't have to worry about
4511 * disk_len vs real len like with real inodes since it's all
4512 * disk length.
4513 */
4514 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4515 sums->bytenr = new_bytenr;
4516
4517 btrfs_add_ordered_sum(inode, ordered, sums);
4518 }
4519 out:
4520 btrfs_put_ordered_extent(ordered);
4521 return ret;
4522 }
4523
4524 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4525 struct btrfs_root *root, struct extent_buffer *buf,
4526 struct extent_buffer *cow)
4527 {
4528 struct reloc_control *rc;
4529 struct backref_node *node;
4530 int first_cow = 0;
4531 int level;
4532 int ret = 0;
4533
4534 rc = root->fs_info->reloc_ctl;
4535 if (!rc)
4536 return 0;
4537
4538 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4539 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4540
4541 level = btrfs_header_level(buf);
4542 if (btrfs_header_generation(buf) <=
4543 btrfs_root_last_snapshot(&root->root_item))
4544 first_cow = 1;
4545
4546 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4547 rc->create_reloc_tree) {
4548 WARN_ON(!first_cow && level == 0);
4549
4550 node = rc->backref_cache.path[level];
4551 BUG_ON(node->bytenr != buf->start &&
4552 node->new_bytenr != buf->start);
4553
4554 drop_node_buffer(node);
4555 extent_buffer_get(cow);
4556 node->eb = cow;
4557 node->new_bytenr = cow->start;
4558
4559 if (!node->pending) {
4560 list_move_tail(&node->list,
4561 &rc->backref_cache.pending[level]);
4562 node->pending = 1;
4563 }
4564
4565 if (first_cow)
4566 __mark_block_processed(rc, node);
4567
4568 if (first_cow && level > 0)
4569 rc->nodes_relocated += buf->len;
4570 }
4571
4572 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4573 ret = replace_file_extents(trans, rc, root, cow);
4574 return ret;
4575 }
4576
4577 /*
4578 * called before creating snapshot. it calculates metadata reservation
4579 * requried for relocating tree blocks in the snapshot
4580 */
4581 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4582 struct btrfs_pending_snapshot *pending,
4583 u64 *bytes_to_reserve)
4584 {
4585 struct btrfs_root *root;
4586 struct reloc_control *rc;
4587
4588 root = pending->root;
4589 if (!root->reloc_root)
4590 return;
4591
4592 rc = root->fs_info->reloc_ctl;
4593 if (!rc->merge_reloc_tree)
4594 return;
4595
4596 root = root->reloc_root;
4597 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4598 /*
4599 * relocation is in the stage of merging trees. the space
4600 * used by merging a reloc tree is twice the size of
4601 * relocated tree nodes in the worst case. half for cowing
4602 * the reloc tree, half for cowing the fs tree. the space
4603 * used by cowing the reloc tree will be freed after the
4604 * tree is dropped. if we create snapshot, cowing the fs
4605 * tree may use more space than it frees. so we need
4606 * reserve extra space.
4607 */
4608 *bytes_to_reserve += rc->nodes_relocated;
4609 }
4610
4611 /*
4612 * called after snapshot is created. migrate block reservation
4613 * and create reloc root for the newly created snapshot
4614 */
4615 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4616 struct btrfs_pending_snapshot *pending)
4617 {
4618 struct btrfs_root *root = pending->root;
4619 struct btrfs_root *reloc_root;
4620 struct btrfs_root *new_root;
4621 struct reloc_control *rc;
4622 int ret;
4623
4624 if (!root->reloc_root)
4625 return 0;
4626
4627 rc = root->fs_info->reloc_ctl;
4628 rc->merging_rsv_size += rc->nodes_relocated;
4629
4630 if (rc->merge_reloc_tree) {
4631 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4632 rc->block_rsv,
4633 rc->nodes_relocated);
4634 if (ret)
4635 return ret;
4636 }
4637
4638 new_root = pending->snap;
4639 reloc_root = create_reloc_root(trans, root->reloc_root,
4640 new_root->root_key.objectid);
4641 if (IS_ERR(reloc_root))
4642 return PTR_ERR(reloc_root);
4643
4644 ret = __add_reloc_root(reloc_root);
4645 BUG_ON(ret < 0);
4646 new_root->reloc_root = reloc_root;
4647
4648 if (rc->create_reloc_tree)
4649 ret = clone_backref_node(trans, rc, root, reloc_root);
4650 return ret;
4651 }
Linux with added FPC-III support