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Linux 3.12.5
[linux/fpc-iii.git] / fs / btrfs / relocation.c
blob26450d850f149095c53b6ec6270e13c342ea88ea
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 int clear_rsv = 0;
1387 int ret;
1388
1389 if (root->reloc_root) {
1390 reloc_root = root->reloc_root;
1391 reloc_root->last_trans = trans->transid;
1392 return 0;
1393 }
1394
1395 if (!rc || !rc->create_reloc_tree ||
1396 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1397 return 0;
1398
1399 if (!trans->block_rsv) {
1400 trans->block_rsv = rc->block_rsv;
1401 clear_rsv = 1;
1402 }
1403 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1404 if (clear_rsv)
1405 trans->block_rsv = NULL;
1406
1407 ret = __add_reloc_root(reloc_root);
1408 BUG_ON(ret < 0);
1409 root->reloc_root = reloc_root;
1410 return 0;
1411 }
1412
1413 /*
1414 * update root item of reloc tree
1415 */
1416 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1417 struct btrfs_root *root)
1418 {
1419 struct btrfs_root *reloc_root;
1420 struct btrfs_root_item *root_item;
1421 int del = 0;
1422 int ret;
1423
1424 if (!root->reloc_root)
1425 goto out;
1426
1427 reloc_root = root->reloc_root;
1428 root_item = &reloc_root->root_item;
1429
1430 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1431 btrfs_root_refs(root_item) == 0) {
1432 root->reloc_root = NULL;
1433 del = 1;
1434 }
1435
1436 __update_reloc_root(reloc_root, del);
1437
1438 if (reloc_root->commit_root != reloc_root->node) {
1439 btrfs_set_root_node(root_item, reloc_root->node);
1440 free_extent_buffer(reloc_root->commit_root);
1441 reloc_root->commit_root = btrfs_root_node(reloc_root);
1442 }
1443
1444 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1445 &reloc_root->root_key, root_item);
1446 BUG_ON(ret);
1447
1448 out:
1449 return 0;
1450 }
1451
1452 /*
1453 * helper to find first cached inode with inode number >= objectid
1454 * in a subvolume
1455 */
1456 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1457 {
1458 struct rb_node *node;
1459 struct rb_node *prev;
1460 struct btrfs_inode *entry;
1461 struct inode *inode;
1462
1463 spin_lock(&root->inode_lock);
1464 again:
1465 node = root->inode_tree.rb_node;
1466 prev = NULL;
1467 while (node) {
1468 prev = node;
1469 entry = rb_entry(node, struct btrfs_inode, rb_node);
1470
1471 if (objectid < btrfs_ino(&entry->vfs_inode))
1472 node = node->rb_left;
1473 else if (objectid > btrfs_ino(&entry->vfs_inode))
1474 node = node->rb_right;
1475 else
1476 break;
1477 }
1478 if (!node) {
1479 while (prev) {
1480 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1481 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1482 node = prev;
1483 break;
1484 }
1485 prev = rb_next(prev);
1486 }
1487 }
1488 while (node) {
1489 entry = rb_entry(node, struct btrfs_inode, rb_node);
1490 inode = igrab(&entry->vfs_inode);
1491 if (inode) {
1492 spin_unlock(&root->inode_lock);
1493 return inode;
1494 }
1495
1496 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1497 if (cond_resched_lock(&root->inode_lock))
1498 goto again;
1499
1500 node = rb_next(node);
1501 }
1502 spin_unlock(&root->inode_lock);
1503 return NULL;
1504 }
1505
1506 static int in_block_group(u64 bytenr,
1507 struct btrfs_block_group_cache *block_group)
1508 {
1509 if (bytenr >= block_group->key.objectid &&
1510 bytenr < block_group->key.objectid + block_group->key.offset)
1511 return 1;
1512 return 0;
1513 }
1514
1515 /*
1516 * get new location of data
1517 */
1518 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1519 u64 bytenr, u64 num_bytes)
1520 {
1521 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1522 struct btrfs_path *path;
1523 struct btrfs_file_extent_item *fi;
1524 struct extent_buffer *leaf;
1525 int ret;
1526
1527 path = btrfs_alloc_path();
1528 if (!path)
1529 return -ENOMEM;
1530
1531 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1532 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1533 bytenr, 0);
1534 if (ret < 0)
1535 goto out;
1536 if (ret > 0) {
1537 ret = -ENOENT;
1538 goto out;
1539 }
1540
1541 leaf = path->nodes[0];
1542 fi = btrfs_item_ptr(leaf, path->slots[0],
1543 struct btrfs_file_extent_item);
1544
1545 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1546 btrfs_file_extent_compression(leaf, fi) ||
1547 btrfs_file_extent_encryption(leaf, fi) ||
1548 btrfs_file_extent_other_encoding(leaf, fi));
1549
1550 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1551 ret = -EINVAL;
1552 goto out;
1553 }
1554
1555 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1556 ret = 0;
1557 out:
1558 btrfs_free_path(path);
1559 return ret;
1560 }
1561
1562 /*
1563 * update file extent items in the tree leaf to point to
1564 * the new locations.
1565 */
1566 static noinline_for_stack
1567 int replace_file_extents(struct btrfs_trans_handle *trans,
1568 struct reloc_control *rc,
1569 struct btrfs_root *root,
1570 struct extent_buffer *leaf)
1571 {
1572 struct btrfs_key key;
1573 struct btrfs_file_extent_item *fi;
1574 struct inode *inode = NULL;
1575 u64 parent;
1576 u64 bytenr;
1577 u64 new_bytenr = 0;
1578 u64 num_bytes;
1579 u64 end;
1580 u32 nritems;
1581 u32 i;
1582 int ret = 0;
1583 int first = 1;
1584 int dirty = 0;
1585
1586 if (rc->stage != UPDATE_DATA_PTRS)
1587 return 0;
1588
1589 /* reloc trees always use full backref */
1590 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1591 parent = leaf->start;
1592 else
1593 parent = 0;
1594
1595 nritems = btrfs_header_nritems(leaf);
1596 for (i = 0; i < nritems; i++) {
1597 cond_resched();
1598 btrfs_item_key_to_cpu(leaf, &key, i);
1599 if (key.type != BTRFS_EXTENT_DATA_KEY)
1600 continue;
1601 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1602 if (btrfs_file_extent_type(leaf, fi) ==
1603 BTRFS_FILE_EXTENT_INLINE)
1604 continue;
1605 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1606 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1607 if (bytenr == 0)
1608 continue;
1609 if (!in_block_group(bytenr, rc->block_group))
1610 continue;
1611
1612 /*
1613 * if we are modifying block in fs tree, wait for readpage
1614 * to complete and drop the extent cache
1615 */
1616 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1617 if (first) {
1618 inode = find_next_inode(root, key.objectid);
1619 first = 0;
1620 } else if (inode && btrfs_ino(inode) < key.objectid) {
1621 btrfs_add_delayed_iput(inode);
1622 inode = find_next_inode(root, key.objectid);
1623 }
1624 if (inode && btrfs_ino(inode) == key.objectid) {
1625 end = key.offset +
1626 btrfs_file_extent_num_bytes(leaf, fi);
1627 WARN_ON(!IS_ALIGNED(key.offset,
1628 root->sectorsize));
1629 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1630 end--;
1631 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1632 key.offset, end);
1633 if (!ret)
1634 continue;
1635
1636 btrfs_drop_extent_cache(inode, key.offset, end,
1637 1);
1638 unlock_extent(&BTRFS_I(inode)->io_tree,
1639 key.offset, end);
1640 }
1641 }
1642
1643 ret = get_new_location(rc->data_inode, &new_bytenr,
1644 bytenr, num_bytes);
1645 if (ret) {
1646 /*
1647 * Don't have to abort since we've not changed anything
1648 * in the file extent yet.
1649 */
1650 break;
1651 }
1652
1653 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1654 dirty = 1;
1655
1656 key.offset -= btrfs_file_extent_offset(leaf, fi);
1657 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1658 num_bytes, parent,
1659 btrfs_header_owner(leaf),
1660 key.objectid, key.offset, 1);
1661 if (ret) {
1662 btrfs_abort_transaction(trans, root, ret);
1663 break;
1664 }
1665
1666 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1667 parent, btrfs_header_owner(leaf),
1668 key.objectid, key.offset, 1);
1669 if (ret) {
1670 btrfs_abort_transaction(trans, root, ret);
1671 break;
1672 }
1673 }
1674 if (dirty)
1675 btrfs_mark_buffer_dirty(leaf);
1676 if (inode)
1677 btrfs_add_delayed_iput(inode);
1678 return ret;
1679 }
1680
1681 static noinline_for_stack
1682 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1683 struct btrfs_path *path, int level)
1684 {
1685 struct btrfs_disk_key key1;
1686 struct btrfs_disk_key key2;
1687 btrfs_node_key(eb, &key1, slot);
1688 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1689 return memcmp(&key1, &key2, sizeof(key1));
1690 }
1691
1692 /*
1693 * try to replace tree blocks in fs tree with the new blocks
1694 * in reloc tree. tree blocks haven't been modified since the
1695 * reloc tree was create can be replaced.
1696 *
1697 * if a block was replaced, level of the block + 1 is returned.
1698 * if no block got replaced, 0 is returned. if there are other
1699 * errors, a negative error number is returned.
1700 */
1701 static noinline_for_stack
1702 int replace_path(struct btrfs_trans_handle *trans,
1703 struct btrfs_root *dest, struct btrfs_root *src,
1704 struct btrfs_path *path, struct btrfs_key *next_key,
1705 int lowest_level, int max_level)
1706 {
1707 struct extent_buffer *eb;
1708 struct extent_buffer *parent;
1709 struct btrfs_key key;
1710 u64 old_bytenr;
1711 u64 new_bytenr;
1712 u64 old_ptr_gen;
1713 u64 new_ptr_gen;
1714 u64 last_snapshot;
1715 u32 blocksize;
1716 int cow = 0;
1717 int level;
1718 int ret;
1719 int slot;
1720
1721 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1722 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1723
1724 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1725 again:
1726 slot = path->slots[lowest_level];
1727 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1728
1729 eb = btrfs_lock_root_node(dest);
1730 btrfs_set_lock_blocking(eb);
1731 level = btrfs_header_level(eb);
1732
1733 if (level < lowest_level) {
1734 btrfs_tree_unlock(eb);
1735 free_extent_buffer(eb);
1736 return 0;
1737 }
1738
1739 if (cow) {
1740 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1741 BUG_ON(ret);
1742 }
1743 btrfs_set_lock_blocking(eb);
1744
1745 if (next_key) {
1746 next_key->objectid = (u64)-1;
1747 next_key->type = (u8)-1;
1748 next_key->offset = (u64)-1;
1749 }
1750
1751 parent = eb;
1752 while (1) {
1753 level = btrfs_header_level(parent);
1754 BUG_ON(level < lowest_level);
1755
1756 ret = btrfs_bin_search(parent, &key, level, &slot);
1757 if (ret && slot > 0)
1758 slot--;
1759
1760 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1761 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1762
1763 old_bytenr = btrfs_node_blockptr(parent, slot);
1764 blocksize = btrfs_level_size(dest, level - 1);
1765 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1766
1767 if (level <= max_level) {
1768 eb = path->nodes[level];
1769 new_bytenr = btrfs_node_blockptr(eb,
1770 path->slots[level]);
1771 new_ptr_gen = btrfs_node_ptr_generation(eb,
1772 path->slots[level]);
1773 } else {
1774 new_bytenr = 0;
1775 new_ptr_gen = 0;
1776 }
1777
1778 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1779 WARN_ON(1);
1780 ret = level;
1781 break;
1782 }
1783
1784 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1785 memcmp_node_keys(parent, slot, path, level)) {
1786 if (level <= lowest_level) {
1787 ret = 0;
1788 break;
1789 }
1790
1791 eb = read_tree_block(dest, old_bytenr, blocksize,
1792 old_ptr_gen);
1793 if (!eb || !extent_buffer_uptodate(eb)) {
1794 ret = (!eb) ? -ENOMEM : -EIO;
1795 free_extent_buffer(eb);
1796 break;
1797 }
1798 btrfs_tree_lock(eb);
1799 if (cow) {
1800 ret = btrfs_cow_block(trans, dest, eb, parent,
1801 slot, &eb);
1802 BUG_ON(ret);
1803 }
1804 btrfs_set_lock_blocking(eb);
1805
1806 btrfs_tree_unlock(parent);
1807 free_extent_buffer(parent);
1808
1809 parent = eb;
1810 continue;
1811 }
1812
1813 if (!cow) {
1814 btrfs_tree_unlock(parent);
1815 free_extent_buffer(parent);
1816 cow = 1;
1817 goto again;
1818 }
1819
1820 btrfs_node_key_to_cpu(path->nodes[level], &key,
1821 path->slots[level]);
1822 btrfs_release_path(path);
1823
1824 path->lowest_level = level;
1825 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1826 path->lowest_level = 0;
1827 BUG_ON(ret);
1828
1829 /*
1830 * swap blocks in fs tree and reloc tree.
1831 */
1832 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1833 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1834 btrfs_mark_buffer_dirty(parent);
1835
1836 btrfs_set_node_blockptr(path->nodes[level],
1837 path->slots[level], old_bytenr);
1838 btrfs_set_node_ptr_generation(path->nodes[level],
1839 path->slots[level], old_ptr_gen);
1840 btrfs_mark_buffer_dirty(path->nodes[level]);
1841
1842 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1843 path->nodes[level]->start,
1844 src->root_key.objectid, level - 1, 0,
1845 1);
1846 BUG_ON(ret);
1847 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1848 0, dest->root_key.objectid, level - 1,
1849 0, 1);
1850 BUG_ON(ret);
1851
1852 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1853 path->nodes[level]->start,
1854 src->root_key.objectid, level - 1, 0,
1855 1);
1856 BUG_ON(ret);
1857
1858 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1859 0, dest->root_key.objectid, level - 1,
1860 0, 1);
1861 BUG_ON(ret);
1862
1863 btrfs_unlock_up_safe(path, 0);
1864
1865 ret = level;
1866 break;
1867 }
1868 btrfs_tree_unlock(parent);
1869 free_extent_buffer(parent);
1870 return ret;
1871 }
1872
1873 /*
1874 * helper to find next relocated block in reloc tree
1875 */
1876 static noinline_for_stack
1877 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1878 int *level)
1879 {
1880 struct extent_buffer *eb;
1881 int i;
1882 u64 last_snapshot;
1883 u32 nritems;
1884
1885 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1886
1887 for (i = 0; i < *level; i++) {
1888 free_extent_buffer(path->nodes[i]);
1889 path->nodes[i] = NULL;
1890 }
1891
1892 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1893 eb = path->nodes[i];
1894 nritems = btrfs_header_nritems(eb);
1895 while (path->slots[i] + 1 < nritems) {
1896 path->slots[i]++;
1897 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1898 last_snapshot)
1899 continue;
1900
1901 *level = i;
1902 return 0;
1903 }
1904 free_extent_buffer(path->nodes[i]);
1905 path->nodes[i] = NULL;
1906 }
1907 return 1;
1908 }
1909
1910 /*
1911 * walk down reloc tree to find relocated block of lowest level
1912 */
1913 static noinline_for_stack
1914 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1915 int *level)
1916 {
1917 struct extent_buffer *eb = NULL;
1918 int i;
1919 u64 bytenr;
1920 u64 ptr_gen = 0;
1921 u64 last_snapshot;
1922 u32 blocksize;
1923 u32 nritems;
1924
1925 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1926
1927 for (i = *level; i > 0; i--) {
1928 eb = path->nodes[i];
1929 nritems = btrfs_header_nritems(eb);
1930 while (path->slots[i] < nritems) {
1931 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1932 if (ptr_gen > last_snapshot)
1933 break;
1934 path->slots[i]++;
1935 }
1936 if (path->slots[i] >= nritems) {
1937 if (i == *level)
1938 break;
1939 *level = i + 1;
1940 return 0;
1941 }
1942 if (i == 1) {
1943 *level = i;
1944 return 0;
1945 }
1946
1947 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1948 blocksize = btrfs_level_size(root, i - 1);
1949 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1950 if (!eb || !extent_buffer_uptodate(eb)) {
1951 free_extent_buffer(eb);
1952 return -EIO;
1953 }
1954 BUG_ON(btrfs_header_level(eb) != i - 1);
1955 path->nodes[i - 1] = eb;
1956 path->slots[i - 1] = 0;
1957 }
1958 return 1;
1959 }
1960
1961 /*
1962 * invalidate extent cache for file extents whose key in range of
1963 * [min_key, max_key)
1964 */
1965 static int invalidate_extent_cache(struct btrfs_root *root,
1966 struct btrfs_key *min_key,
1967 struct btrfs_key *max_key)
1968 {
1969 struct inode *inode = NULL;
1970 u64 objectid;
1971 u64 start, end;
1972 u64 ino;
1973
1974 objectid = min_key->objectid;
1975 while (1) {
1976 cond_resched();
1977 iput(inode);
1978
1979 if (objectid > max_key->objectid)
1980 break;
1981
1982 inode = find_next_inode(root, objectid);
1983 if (!inode)
1984 break;
1985 ino = btrfs_ino(inode);
1986
1987 if (ino > max_key->objectid) {
1988 iput(inode);
1989 break;
1990 }
1991
1992 objectid = ino + 1;
1993 if (!S_ISREG(inode->i_mode))
1994 continue;
1995
1996 if (unlikely(min_key->objectid == ino)) {
1997 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1998 continue;
1999 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2000 start = 0;
2001 else {
2002 start = min_key->offset;
2003 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
2004 }
2005 } else {
2006 start = 0;
2007 }
2008
2009 if (unlikely(max_key->objectid == ino)) {
2010 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2011 continue;
2012 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2013 end = (u64)-1;
2014 } else {
2015 if (max_key->offset == 0)
2016 continue;
2017 end = max_key->offset;
2018 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
2019 end--;
2020 }
2021 } else {
2022 end = (u64)-1;
2023 }
2024
2025 /* the lock_extent waits for readpage to complete */
2026 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2027 btrfs_drop_extent_cache(inode, start, end, 1);
2028 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2029 }
2030 return 0;
2031 }
2032
2033 static int find_next_key(struct btrfs_path *path, int level,
2034 struct btrfs_key *key)
2035
2036 {
2037 while (level < BTRFS_MAX_LEVEL) {
2038 if (!path->nodes[level])
2039 break;
2040 if (path->slots[level] + 1 <
2041 btrfs_header_nritems(path->nodes[level])) {
2042 btrfs_node_key_to_cpu(path->nodes[level], key,
2043 path->slots[level] + 1);
2044 return 0;
2045 }
2046 level++;
2047 }
2048 return 1;
2049 }
2050
2051 /*
2052 * merge the relocated tree blocks in reloc tree with corresponding
2053 * fs tree.
2054 */
2055 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2056 struct btrfs_root *root)
2057 {
2058 LIST_HEAD(inode_list);
2059 struct btrfs_key key;
2060 struct btrfs_key next_key;
2061 struct btrfs_trans_handle *trans;
2062 struct btrfs_root *reloc_root;
2063 struct btrfs_root_item *root_item;
2064 struct btrfs_path *path;
2065 struct extent_buffer *leaf;
2066 int level;
2067 int max_level;
2068 int replaced = 0;
2069 int ret;
2070 int err = 0;
2071 u32 min_reserved;
2072
2073 path = btrfs_alloc_path();
2074 if (!path)
2075 return -ENOMEM;
2076 path->reada = 1;
2077
2078 reloc_root = root->reloc_root;
2079 root_item = &reloc_root->root_item;
2080
2081 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2082 level = btrfs_root_level(root_item);
2083 extent_buffer_get(reloc_root->node);
2084 path->nodes[level] = reloc_root->node;
2085 path->slots[level] = 0;
2086 } else {
2087 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2088
2089 level = root_item->drop_level;
2090 BUG_ON(level == 0);
2091 path->lowest_level = level;
2092 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2093 path->lowest_level = 0;
2094 if (ret < 0) {
2095 btrfs_free_path(path);
2096 return ret;
2097 }
2098
2099 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2100 path->slots[level]);
2101 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2102
2103 btrfs_unlock_up_safe(path, 0);
2104 }
2105
2106 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2107 memset(&next_key, 0, sizeof(next_key));
2108
2109 while (1) {
2110 trans = btrfs_start_transaction(root, 0);
2111 BUG_ON(IS_ERR(trans));
2112 trans->block_rsv = rc->block_rsv;
2113
2114 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2115 BTRFS_RESERVE_FLUSH_ALL);
2116 if (ret) {
2117 BUG_ON(ret != -EAGAIN);
2118 ret = btrfs_commit_transaction(trans, root);
2119 BUG_ON(ret);
2120 continue;
2121 }
2122
2123 replaced = 0;
2124 max_level = level;
2125
2126 ret = walk_down_reloc_tree(reloc_root, path, &level);
2127 if (ret < 0) {
2128 err = ret;
2129 goto out;
2130 }
2131 if (ret > 0)
2132 break;
2133
2134 if (!find_next_key(path, level, &key) &&
2135 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2136 ret = 0;
2137 } else {
2138 ret = replace_path(trans, root, reloc_root, path,
2139 &next_key, level, max_level);
2140 }
2141 if (ret < 0) {
2142 err = ret;
2143 goto out;
2144 }
2145
2146 if (ret > 0) {
2147 level = ret;
2148 btrfs_node_key_to_cpu(path->nodes[level], &key,
2149 path->slots[level]);
2150 replaced = 1;
2151 }
2152
2153 ret = walk_up_reloc_tree(reloc_root, path, &level);
2154 if (ret > 0)
2155 break;
2156
2157 BUG_ON(level == 0);
2158 /*
2159 * save the merging progress in the drop_progress.
2160 * this is OK since root refs == 1 in this case.
2161 */
2162 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2163 path->slots[level]);
2164 root_item->drop_level = level;
2165
2166 btrfs_end_transaction_throttle(trans, root);
2167
2168 btrfs_btree_balance_dirty(root);
2169
2170 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2171 invalidate_extent_cache(root, &key, &next_key);
2172 }
2173
2174 /*
2175 * handle the case only one block in the fs tree need to be
2176 * relocated and the block is tree root.
2177 */
2178 leaf = btrfs_lock_root_node(root);
2179 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2180 btrfs_tree_unlock(leaf);
2181 free_extent_buffer(leaf);
2182 if (ret < 0)
2183 err = ret;
2184 out:
2185 btrfs_free_path(path);
2186
2187 if (err == 0) {
2188 memset(&root_item->drop_progress, 0,
2189 sizeof(root_item->drop_progress));
2190 root_item->drop_level = 0;
2191 btrfs_set_root_refs(root_item, 0);
2192 btrfs_update_reloc_root(trans, root);
2193 }
2194
2195 btrfs_end_transaction_throttle(trans, root);
2196
2197 btrfs_btree_balance_dirty(root);
2198
2199 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2200 invalidate_extent_cache(root, &key, &next_key);
2201
2202 return err;
2203 }
2204
2205 static noinline_for_stack
2206 int prepare_to_merge(struct reloc_control *rc, int err)
2207 {
2208 struct btrfs_root *root = rc->extent_root;
2209 struct btrfs_root *reloc_root;
2210 struct btrfs_trans_handle *trans;
2211 LIST_HEAD(reloc_roots);
2212 u64 num_bytes = 0;
2213 int ret;
2214
2215 mutex_lock(&root->fs_info->reloc_mutex);
2216 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2217 rc->merging_rsv_size += rc->nodes_relocated * 2;
2218 mutex_unlock(&root->fs_info->reloc_mutex);
2219
2220 again:
2221 if (!err) {
2222 num_bytes = rc->merging_rsv_size;
2223 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2224 BTRFS_RESERVE_FLUSH_ALL);
2225 if (ret)
2226 err = ret;
2227 }
2228
2229 trans = btrfs_join_transaction(rc->extent_root);
2230 if (IS_ERR(trans)) {
2231 if (!err)
2232 btrfs_block_rsv_release(rc->extent_root,
2233 rc->block_rsv, num_bytes);
2234 return PTR_ERR(trans);
2235 }
2236
2237 if (!err) {
2238 if (num_bytes != rc->merging_rsv_size) {
2239 btrfs_end_transaction(trans, rc->extent_root);
2240 btrfs_block_rsv_release(rc->extent_root,
2241 rc->block_rsv, num_bytes);
2242 goto again;
2243 }
2244 }
2245
2246 rc->merge_reloc_tree = 1;
2247
2248 while (!list_empty(&rc->reloc_roots)) {
2249 reloc_root = list_entry(rc->reloc_roots.next,
2250 struct btrfs_root, root_list);
2251 list_del_init(&reloc_root->root_list);
2252
2253 root = read_fs_root(reloc_root->fs_info,
2254 reloc_root->root_key.offset);
2255 BUG_ON(IS_ERR(root));
2256 BUG_ON(root->reloc_root != reloc_root);
2257
2258 /*
2259 * set reference count to 1, so btrfs_recover_relocation
2260 * knows it should resumes merging
2261 */
2262 if (!err)
2263 btrfs_set_root_refs(&reloc_root->root_item, 1);
2264 btrfs_update_reloc_root(trans, root);
2265
2266 list_add(&reloc_root->root_list, &reloc_roots);
2267 }
2268
2269 list_splice(&reloc_roots, &rc->reloc_roots);
2270
2271 if (!err)
2272 btrfs_commit_transaction(trans, rc->extent_root);
2273 else
2274 btrfs_end_transaction(trans, rc->extent_root);
2275 return err;
2276 }
2277
2278 static noinline_for_stack
2279 void free_reloc_roots(struct list_head *list)
2280 {
2281 struct btrfs_root *reloc_root;
2282
2283 while (!list_empty(list)) {
2284 reloc_root = list_entry(list->next, struct btrfs_root,
2285 root_list);
2286 __update_reloc_root(reloc_root, 1);
2287 free_extent_buffer(reloc_root->node);
2288 free_extent_buffer(reloc_root->commit_root);
2289 kfree(reloc_root);
2290 }
2291 }
2292
2293 static noinline_for_stack
2294 int merge_reloc_roots(struct reloc_control *rc)
2295 {
2296 struct btrfs_trans_handle *trans;
2297 struct btrfs_root *root;
2298 struct btrfs_root *reloc_root;
2299 u64 last_snap;
2300 u64 otransid;
2301 u64 objectid;
2302 LIST_HEAD(reloc_roots);
2303 int found = 0;
2304 int ret = 0;
2305 again:
2306 root = rc->extent_root;
2307
2308 /*
2309 * this serializes us with btrfs_record_root_in_transaction,
2310 * we have to make sure nobody is in the middle of
2311 * adding their roots to the list while we are
2312 * doing this splice
2313 */
2314 mutex_lock(&root->fs_info->reloc_mutex);
2315 list_splice_init(&rc->reloc_roots, &reloc_roots);
2316 mutex_unlock(&root->fs_info->reloc_mutex);
2317
2318 while (!list_empty(&reloc_roots)) {
2319 found = 1;
2320 reloc_root = list_entry(reloc_roots.next,
2321 struct btrfs_root, root_list);
2322
2323 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2324 root = read_fs_root(reloc_root->fs_info,
2325 reloc_root->root_key.offset);
2326 BUG_ON(IS_ERR(root));
2327 BUG_ON(root->reloc_root != reloc_root);
2328
2329 ret = merge_reloc_root(rc, root);
2330 if (ret) {
2331 __update_reloc_root(reloc_root, 1);
2332 free_extent_buffer(reloc_root->node);
2333 free_extent_buffer(reloc_root->commit_root);
2334 kfree(reloc_root);
2335 goto out;
2336 }
2337 } else {
2338 list_del_init(&reloc_root->root_list);
2339 }
2340
2341 /*
2342 * we keep the old last snapshod transid in rtranid when we
2343 * created the relocation tree.
2344 */
2345 last_snap = btrfs_root_rtransid(&reloc_root->root_item);
2346 otransid = btrfs_root_otransid(&reloc_root->root_item);
2347 objectid = reloc_root->root_key.offset;
2348
2349 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2350 if (ret < 0) {
2351 if (list_empty(&reloc_root->root_list))
2352 list_add_tail(&reloc_root->root_list,
2353 &reloc_roots);
2354 goto out;
2355 } else if (!ret) {
2356 /*
2357 * recover the last snapshot tranid to avoid
2358 * the space balance break NOCOW.
2359 */
2360 root = read_fs_root(rc->extent_root->fs_info,
2361 objectid);
2362 if (IS_ERR(root))
2363 continue;
2364
2365 trans = btrfs_join_transaction(root);
2366 BUG_ON(IS_ERR(trans));
2367
2368 /* Check if the fs/file tree was snapshoted or not. */
2369 if (btrfs_root_last_snapshot(&root->root_item) ==
2370 otransid - 1)
2371 btrfs_set_root_last_snapshot(&root->root_item,
2372 last_snap);
2373
2374 btrfs_end_transaction(trans, root);
2375 }
2376 }
2377
2378 if (found) {
2379 found = 0;
2380 goto again;
2381 }
2382 out:
2383 if (ret) {
2384 btrfs_std_error(root->fs_info, ret);
2385 if (!list_empty(&reloc_roots))
2386 free_reloc_roots(&reloc_roots);
2387 }
2388
2389 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2390 return ret;
2391 }
2392
2393 static void free_block_list(struct rb_root *blocks)
2394 {
2395 struct tree_block *block;
2396 struct rb_node *rb_node;
2397 while ((rb_node = rb_first(blocks))) {
2398 block = rb_entry(rb_node, struct tree_block, rb_node);
2399 rb_erase(rb_node, blocks);
2400 kfree(block);
2401 }
2402 }
2403
2404 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2405 struct btrfs_root *reloc_root)
2406 {
2407 struct btrfs_root *root;
2408
2409 if (reloc_root->last_trans == trans->transid)
2410 return 0;
2411
2412 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2413 BUG_ON(IS_ERR(root));
2414 BUG_ON(root->reloc_root != reloc_root);
2415
2416 return btrfs_record_root_in_trans(trans, root);
2417 }
2418
2419 static noinline_for_stack
2420 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2421 struct reloc_control *rc,
2422 struct backref_node *node,
2423 struct backref_edge *edges[], int *nr)
2424 {
2425 struct backref_node *next;
2426 struct btrfs_root *root;
2427 int index = 0;
2428
2429 next = node;
2430 while (1) {
2431 cond_resched();
2432 next = walk_up_backref(next, edges, &index);
2433 root = next->root;
2434 BUG_ON(!root);
2435 BUG_ON(!root->ref_cows);
2436
2437 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2438 record_reloc_root_in_trans(trans, root);
2439 break;
2440 }
2441
2442 btrfs_record_root_in_trans(trans, root);
2443 root = root->reloc_root;
2444
2445 if (next->new_bytenr != root->node->start) {
2446 BUG_ON(next->new_bytenr);
2447 BUG_ON(!list_empty(&next->list));
2448 next->new_bytenr = root->node->start;
2449 next->root = root;
2450 list_add_tail(&next->list,
2451 &rc->backref_cache.changed);
2452 __mark_block_processed(rc, next);
2453 break;
2454 }
2455
2456 WARN_ON(1);
2457 root = NULL;
2458 next = walk_down_backref(edges, &index);
2459 if (!next || next->level <= node->level)
2460 break;
2461 }
2462 if (!root)
2463 return NULL;
2464
2465 *nr = index;
2466 next = node;
2467 /* setup backref node path for btrfs_reloc_cow_block */
2468 while (1) {
2469 rc->backref_cache.path[next->level] = next;
2470 if (--index < 0)
2471 break;
2472 next = edges[index]->node[UPPER];
2473 }
2474 return root;
2475 }
2476
2477 /*
2478 * select a tree root for relocation. return NULL if the block
2479 * is reference counted. we should use do_relocation() in this
2480 * case. return a tree root pointer if the block isn't reference
2481 * counted. return -ENOENT if the block is root of reloc tree.
2482 */
2483 static noinline_for_stack
2484 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2485 struct backref_node *node)
2486 {
2487 struct backref_node *next;
2488 struct btrfs_root *root;
2489 struct btrfs_root *fs_root = NULL;
2490 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2491 int index = 0;
2492
2493 next = node;
2494 while (1) {
2495 cond_resched();
2496 next = walk_up_backref(next, edges, &index);
2497 root = next->root;
2498 BUG_ON(!root);
2499
2500 /* no other choice for non-references counted tree */
2501 if (!root->ref_cows)
2502 return root;
2503
2504 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2505 fs_root = root;
2506
2507 if (next != node)
2508 return NULL;
2509
2510 next = walk_down_backref(edges, &index);
2511 if (!next || next->level <= node->level)
2512 break;
2513 }
2514
2515 if (!fs_root)
2516 return ERR_PTR(-ENOENT);
2517 return fs_root;
2518 }
2519
2520 static noinline_for_stack
2521 u64 calcu_metadata_size(struct reloc_control *rc,
2522 struct backref_node *node, int reserve)
2523 {
2524 struct backref_node *next = node;
2525 struct backref_edge *edge;
2526 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2527 u64 num_bytes = 0;
2528 int index = 0;
2529
2530 BUG_ON(reserve && node->processed);
2531
2532 while (next) {
2533 cond_resched();
2534 while (1) {
2535 if (next->processed && (reserve || next != node))
2536 break;
2537
2538 num_bytes += btrfs_level_size(rc->extent_root,
2539 next->level);
2540
2541 if (list_empty(&next->upper))
2542 break;
2543
2544 edge = list_entry(next->upper.next,
2545 struct backref_edge, list[LOWER]);
2546 edges[index++] = edge;
2547 next = edge->node[UPPER];
2548 }
2549 next = walk_down_backref(edges, &index);
2550 }
2551 return num_bytes;
2552 }
2553
2554 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2555 struct reloc_control *rc,
2556 struct backref_node *node)
2557 {
2558 struct btrfs_root *root = rc->extent_root;
2559 u64 num_bytes;
2560 int ret;
2561
2562 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2563
2564 trans->block_rsv = rc->block_rsv;
2565 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2566 BTRFS_RESERVE_FLUSH_ALL);
2567 if (ret) {
2568 if (ret == -EAGAIN)
2569 rc->commit_transaction = 1;
2570 return ret;
2571 }
2572
2573 return 0;
2574 }
2575
2576 static void release_metadata_space(struct reloc_control *rc,
2577 struct backref_node *node)
2578 {
2579 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2580 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2581 }
2582
2583 /*
2584 * relocate a block tree, and then update pointers in upper level
2585 * blocks that reference the block to point to the new location.
2586 *
2587 * if called by link_to_upper, the block has already been relocated.
2588 * in that case this function just updates pointers.
2589 */
2590 static int do_relocation(struct btrfs_trans_handle *trans,
2591 struct reloc_control *rc,
2592 struct backref_node *node,
2593 struct btrfs_key *key,
2594 struct btrfs_path *path, int lowest)
2595 {
2596 struct backref_node *upper;
2597 struct backref_edge *edge;
2598 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2599 struct btrfs_root *root;
2600 struct extent_buffer *eb;
2601 u32 blocksize;
2602 u64 bytenr;
2603 u64 generation;
2604 int nr;
2605 int slot;
2606 int ret;
2607 int err = 0;
2608
2609 BUG_ON(lowest && node->eb);
2610
2611 path->lowest_level = node->level + 1;
2612 rc->backref_cache.path[node->level] = node;
2613 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2614 cond_resched();
2615
2616 upper = edge->node[UPPER];
2617 root = select_reloc_root(trans, rc, upper, edges, &nr);
2618 BUG_ON(!root);
2619
2620 if (upper->eb && !upper->locked) {
2621 if (!lowest) {
2622 ret = btrfs_bin_search(upper->eb, key,
2623 upper->level, &slot);
2624 BUG_ON(ret);
2625 bytenr = btrfs_node_blockptr(upper->eb, slot);
2626 if (node->eb->start == bytenr)
2627 goto next;
2628 }
2629 drop_node_buffer(upper);
2630 }
2631
2632 if (!upper->eb) {
2633 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2634 if (ret < 0) {
2635 err = ret;
2636 break;
2637 }
2638 BUG_ON(ret > 0);
2639
2640 if (!upper->eb) {
2641 upper->eb = path->nodes[upper->level];
2642 path->nodes[upper->level] = NULL;
2643 } else {
2644 BUG_ON(upper->eb != path->nodes[upper->level]);
2645 }
2646
2647 upper->locked = 1;
2648 path->locks[upper->level] = 0;
2649
2650 slot = path->slots[upper->level];
2651 btrfs_release_path(path);
2652 } else {
2653 ret = btrfs_bin_search(upper->eb, key, upper->level,
2654 &slot);
2655 BUG_ON(ret);
2656 }
2657
2658 bytenr = btrfs_node_blockptr(upper->eb, slot);
2659 if (lowest) {
2660 BUG_ON(bytenr != node->bytenr);
2661 } else {
2662 if (node->eb->start == bytenr)
2663 goto next;
2664 }
2665
2666 blocksize = btrfs_level_size(root, node->level);
2667 generation = btrfs_node_ptr_generation(upper->eb, slot);
2668 eb = read_tree_block(root, bytenr, blocksize, generation);
2669 if (!eb || !extent_buffer_uptodate(eb)) {
2670 free_extent_buffer(eb);
2671 err = -EIO;
2672 goto next;
2673 }
2674 btrfs_tree_lock(eb);
2675 btrfs_set_lock_blocking(eb);
2676
2677 if (!node->eb) {
2678 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2679 slot, &eb);
2680 btrfs_tree_unlock(eb);
2681 free_extent_buffer(eb);
2682 if (ret < 0) {
2683 err = ret;
2684 goto next;
2685 }
2686 BUG_ON(node->eb != eb);
2687 } else {
2688 btrfs_set_node_blockptr(upper->eb, slot,
2689 node->eb->start);
2690 btrfs_set_node_ptr_generation(upper->eb, slot,
2691 trans->transid);
2692 btrfs_mark_buffer_dirty(upper->eb);
2693
2694 ret = btrfs_inc_extent_ref(trans, root,
2695 node->eb->start, blocksize,
2696 upper->eb->start,
2697 btrfs_header_owner(upper->eb),
2698 node->level, 0, 1);
2699 BUG_ON(ret);
2700
2701 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2702 BUG_ON(ret);
2703 }
2704 next:
2705 if (!upper->pending)
2706 drop_node_buffer(upper);
2707 else
2708 unlock_node_buffer(upper);
2709 if (err)
2710 break;
2711 }
2712
2713 if (!err && node->pending) {
2714 drop_node_buffer(node);
2715 list_move_tail(&node->list, &rc->backref_cache.changed);
2716 node->pending = 0;
2717 }
2718
2719 path->lowest_level = 0;
2720 BUG_ON(err == -ENOSPC);
2721 return err;
2722 }
2723
2724 static int link_to_upper(struct btrfs_trans_handle *trans,
2725 struct reloc_control *rc,
2726 struct backref_node *node,
2727 struct btrfs_path *path)
2728 {
2729 struct btrfs_key key;
2730
2731 btrfs_node_key_to_cpu(node->eb, &key, 0);
2732 return do_relocation(trans, rc, node, &key, path, 0);
2733 }
2734
2735 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2736 struct reloc_control *rc,
2737 struct btrfs_path *path, int err)
2738 {
2739 LIST_HEAD(list);
2740 struct backref_cache *cache = &rc->backref_cache;
2741 struct backref_node *node;
2742 int level;
2743 int ret;
2744
2745 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2746 while (!list_empty(&cache->pending[level])) {
2747 node = list_entry(cache->pending[level].next,
2748 struct backref_node, list);
2749 list_move_tail(&node->list, &list);
2750 BUG_ON(!node->pending);
2751
2752 if (!err) {
2753 ret = link_to_upper(trans, rc, node, path);
2754 if (ret < 0)
2755 err = ret;
2756 }
2757 }
2758 list_splice_init(&list, &cache->pending[level]);
2759 }
2760 return err;
2761 }
2762
2763 static void mark_block_processed(struct reloc_control *rc,
2764 u64 bytenr, u32 blocksize)
2765 {
2766 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2767 EXTENT_DIRTY, GFP_NOFS);
2768 }
2769
2770 static void __mark_block_processed(struct reloc_control *rc,
2771 struct backref_node *node)
2772 {
2773 u32 blocksize;
2774 if (node->level == 0 ||
2775 in_block_group(node->bytenr, rc->block_group)) {
2776 blocksize = btrfs_level_size(rc->extent_root, node->level);
2777 mark_block_processed(rc, node->bytenr, blocksize);
2778 }
2779 node->processed = 1;
2780 }
2781
2782 /*
2783 * mark a block and all blocks directly/indirectly reference the block
2784 * as processed.
2785 */
2786 static void update_processed_blocks(struct reloc_control *rc,
2787 struct backref_node *node)
2788 {
2789 struct backref_node *next = node;
2790 struct backref_edge *edge;
2791 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2792 int index = 0;
2793
2794 while (next) {
2795 cond_resched();
2796 while (1) {
2797 if (next->processed)
2798 break;
2799
2800 __mark_block_processed(rc, next);
2801
2802 if (list_empty(&next->upper))
2803 break;
2804
2805 edge = list_entry(next->upper.next,
2806 struct backref_edge, list[LOWER]);
2807 edges[index++] = edge;
2808 next = edge->node[UPPER];
2809 }
2810 next = walk_down_backref(edges, &index);
2811 }
2812 }
2813
2814 static int tree_block_processed(u64 bytenr, u32 blocksize,
2815 struct reloc_control *rc)
2816 {
2817 if (test_range_bit(&rc->processed_blocks, bytenr,
2818 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2819 return 1;
2820 return 0;
2821 }
2822
2823 static int get_tree_block_key(struct reloc_control *rc,
2824 struct tree_block *block)
2825 {
2826 struct extent_buffer *eb;
2827
2828 BUG_ON(block->key_ready);
2829 eb = read_tree_block(rc->extent_root, block->bytenr,
2830 block->key.objectid, block->key.offset);
2831 if (!eb || !extent_buffer_uptodate(eb)) {
2832 free_extent_buffer(eb);
2833 return -EIO;
2834 }
2835 WARN_ON(btrfs_header_level(eb) != block->level);
2836 if (block->level == 0)
2837 btrfs_item_key_to_cpu(eb, &block->key, 0);
2838 else
2839 btrfs_node_key_to_cpu(eb, &block->key, 0);
2840 free_extent_buffer(eb);
2841 block->key_ready = 1;
2842 return 0;
2843 }
2844
2845 static int reada_tree_block(struct reloc_control *rc,
2846 struct tree_block *block)
2847 {
2848 BUG_ON(block->key_ready);
2849 if (block->key.type == BTRFS_METADATA_ITEM_KEY)
2850 readahead_tree_block(rc->extent_root, block->bytenr,
2851 block->key.objectid,
2852 rc->extent_root->leafsize);
2853 else
2854 readahead_tree_block(rc->extent_root, block->bytenr,
2855 block->key.objectid, block->key.offset);
2856 return 0;
2857 }
2858
2859 /*
2860 * helper function to relocate a tree block
2861 */
2862 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2863 struct reloc_control *rc,
2864 struct backref_node *node,
2865 struct btrfs_key *key,
2866 struct btrfs_path *path)
2867 {
2868 struct btrfs_root *root;
2869 int release = 0;
2870 int ret = 0;
2871
2872 if (!node)
2873 return 0;
2874
2875 BUG_ON(node->processed);
2876 root = select_one_root(trans, node);
2877 if (root == ERR_PTR(-ENOENT)) {
2878 update_processed_blocks(rc, node);
2879 goto out;
2880 }
2881
2882 if (!root || root->ref_cows) {
2883 ret = reserve_metadata_space(trans, rc, node);
2884 if (ret)
2885 goto out;
2886 release = 1;
2887 }
2888
2889 if (root) {
2890 if (root->ref_cows) {
2891 BUG_ON(node->new_bytenr);
2892 BUG_ON(!list_empty(&node->list));
2893 btrfs_record_root_in_trans(trans, root);
2894 root = root->reloc_root;
2895 node->new_bytenr = root->node->start;
2896 node->root = root;
2897 list_add_tail(&node->list, &rc->backref_cache.changed);
2898 } else {
2899 path->lowest_level = node->level;
2900 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2901 btrfs_release_path(path);
2902 if (ret > 0)
2903 ret = 0;
2904 }
2905 if (!ret)
2906 update_processed_blocks(rc, node);
2907 } else {
2908 ret = do_relocation(trans, rc, node, key, path, 1);
2909 }
2910 out:
2911 if (ret || node->level == 0 || node->cowonly) {
2912 if (release)
2913 release_metadata_space(rc, node);
2914 remove_backref_node(&rc->backref_cache, node);
2915 }
2916 return ret;
2917 }
2918
2919 /*
2920 * relocate a list of blocks
2921 */
2922 static noinline_for_stack
2923 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2924 struct reloc_control *rc, struct rb_root *blocks)
2925 {
2926 struct backref_node *node;
2927 struct btrfs_path *path;
2928 struct tree_block *block;
2929 struct rb_node *rb_node;
2930 int ret;
2931 int err = 0;
2932
2933 path = btrfs_alloc_path();
2934 if (!path) {
2935 err = -ENOMEM;
2936 goto out_free_blocks;
2937 }
2938
2939 rb_node = rb_first(blocks);
2940 while (rb_node) {
2941 block = rb_entry(rb_node, struct tree_block, rb_node);
2942 if (!block->key_ready)
2943 reada_tree_block(rc, block);
2944 rb_node = rb_next(rb_node);
2945 }
2946
2947 rb_node = rb_first(blocks);
2948 while (rb_node) {
2949 block = rb_entry(rb_node, struct tree_block, rb_node);
2950 if (!block->key_ready) {
2951 err = get_tree_block_key(rc, block);
2952 if (err)
2953 goto out_free_path;
2954 }
2955 rb_node = rb_next(rb_node);
2956 }
2957
2958 rb_node = rb_first(blocks);
2959 while (rb_node) {
2960 block = rb_entry(rb_node, struct tree_block, rb_node);
2961
2962 node = build_backref_tree(rc, &block->key,
2963 block->level, block->bytenr);
2964 if (IS_ERR(node)) {
2965 err = PTR_ERR(node);
2966 goto out;
2967 }
2968
2969 ret = relocate_tree_block(trans, rc, node, &block->key,
2970 path);
2971 if (ret < 0) {
2972 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2973 err = ret;
2974 goto out;
2975 }
2976 rb_node = rb_next(rb_node);
2977 }
2978 out:
2979 err = finish_pending_nodes(trans, rc, path, err);
2980
2981 out_free_path:
2982 btrfs_free_path(path);
2983 out_free_blocks:
2984 free_block_list(blocks);
2985 return err;
2986 }
2987
2988 static noinline_for_stack
2989 int prealloc_file_extent_cluster(struct inode *inode,
2990 struct file_extent_cluster *cluster)
2991 {
2992 u64 alloc_hint = 0;
2993 u64 start;
2994 u64 end;
2995 u64 offset = BTRFS_I(inode)->index_cnt;
2996 u64 num_bytes;
2997 int nr = 0;
2998 int ret = 0;
2999
3000 BUG_ON(cluster->start != cluster->boundary[0]);
3001 mutex_lock(&inode->i_mutex);
3002
3003 ret = btrfs_check_data_free_space(inode, cluster->end +
3004 1 - cluster->start);
3005 if (ret)
3006 goto out;
3007
3008 while (nr < cluster->nr) {
3009 start = cluster->boundary[nr] - offset;
3010 if (nr + 1 < cluster->nr)
3011 end = cluster->boundary[nr + 1] - 1 - offset;
3012 else
3013 end = cluster->end - offset;
3014
3015 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3016 num_bytes = end + 1 - start;
3017 ret = btrfs_prealloc_file_range(inode, 0, start,
3018 num_bytes, num_bytes,
3019 end + 1, &alloc_hint);
3020 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3021 if (ret)
3022 break;
3023 nr++;
3024 }
3025 btrfs_free_reserved_data_space(inode, cluster->end +
3026 1 - cluster->start);
3027 out:
3028 mutex_unlock(&inode->i_mutex);
3029 return ret;
3030 }
3031
3032 static noinline_for_stack
3033 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3034 u64 block_start)
3035 {
3036 struct btrfs_root *root = BTRFS_I(inode)->root;
3037 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3038 struct extent_map *em;
3039 int ret = 0;
3040
3041 em = alloc_extent_map();
3042 if (!em)
3043 return -ENOMEM;
3044
3045 em->start = start;
3046 em->len = end + 1 - start;
3047 em->block_len = em->len;
3048 em->block_start = block_start;
3049 em->bdev = root->fs_info->fs_devices->latest_bdev;
3050 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3051
3052 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3053 while (1) {
3054 write_lock(&em_tree->lock);
3055 ret = add_extent_mapping(em_tree, em, 0);
3056 write_unlock(&em_tree->lock);
3057 if (ret != -EEXIST) {
3058 free_extent_map(em);
3059 break;
3060 }
3061 btrfs_drop_extent_cache(inode, start, end, 0);
3062 }
3063 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3064 return ret;
3065 }
3066
3067 static int relocate_file_extent_cluster(struct inode *inode,
3068 struct file_extent_cluster *cluster)
3069 {
3070 u64 page_start;
3071 u64 page_end;
3072 u64 offset = BTRFS_I(inode)->index_cnt;
3073 unsigned long index;
3074 unsigned long last_index;
3075 struct page *page;
3076 struct file_ra_state *ra;
3077 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3078 int nr = 0;
3079 int ret = 0;
3080
3081 if (!cluster->nr)
3082 return 0;
3083
3084 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3085 if (!ra)
3086 return -ENOMEM;
3087
3088 ret = prealloc_file_extent_cluster(inode, cluster);
3089 if (ret)
3090 goto out;
3091
3092 file_ra_state_init(ra, inode->i_mapping);
3093
3094 ret = setup_extent_mapping(inode, cluster->start - offset,
3095 cluster->end - offset, cluster->start);
3096 if (ret)
3097 goto out;
3098
3099 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
3100 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
3101 while (index <= last_index) {
3102 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
3103 if (ret)
3104 goto out;
3105
3106 page = find_lock_page(inode->i_mapping, index);
3107 if (!page) {
3108 page_cache_sync_readahead(inode->i_mapping,
3109 ra, NULL, index,
3110 last_index + 1 - index);
3111 page = find_or_create_page(inode->i_mapping, index,
3112 mask);
3113 if (!page) {
3114 btrfs_delalloc_release_metadata(inode,
3115 PAGE_CACHE_SIZE);
3116 ret = -ENOMEM;
3117 goto out;
3118 }
3119 }
3120
3121 if (PageReadahead(page)) {
3122 page_cache_async_readahead(inode->i_mapping,
3123 ra, NULL, page, index,
3124 last_index + 1 - index);
3125 }
3126
3127 if (!PageUptodate(page)) {
3128 btrfs_readpage(NULL, page);
3129 lock_page(page);
3130 if (!PageUptodate(page)) {
3131 unlock_page(page);
3132 page_cache_release(page);
3133 btrfs_delalloc_release_metadata(inode,
3134 PAGE_CACHE_SIZE);
3135 ret = -EIO;
3136 goto out;
3137 }
3138 }
3139
3140 page_start = page_offset(page);
3141 page_end = page_start + PAGE_CACHE_SIZE - 1;
3142
3143 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3144
3145 set_page_extent_mapped(page);
3146
3147 if (nr < cluster->nr &&
3148 page_start + offset == cluster->boundary[nr]) {
3149 set_extent_bits(&BTRFS_I(inode)->io_tree,
3150 page_start, page_end,
3151 EXTENT_BOUNDARY, GFP_NOFS);
3152 nr++;
3153 }
3154
3155 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3156 set_page_dirty(page);
3157
3158 unlock_extent(&BTRFS_I(inode)->io_tree,
3159 page_start, page_end);
3160 unlock_page(page);
3161 page_cache_release(page);
3162
3163 index++;
3164 balance_dirty_pages_ratelimited(inode->i_mapping);
3165 btrfs_throttle(BTRFS_I(inode)->root);
3166 }
3167 WARN_ON(nr != cluster->nr);
3168 out:
3169 kfree(ra);
3170 return ret;
3171 }
3172
3173 static noinline_for_stack
3174 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3175 struct file_extent_cluster *cluster)
3176 {
3177 int ret;
3178
3179 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3180 ret = relocate_file_extent_cluster(inode, cluster);
3181 if (ret)
3182 return ret;
3183 cluster->nr = 0;
3184 }
3185
3186 if (!cluster->nr)
3187 cluster->start = extent_key->objectid;
3188 else
3189 BUG_ON(cluster->nr >= MAX_EXTENTS);
3190 cluster->end = extent_key->objectid + extent_key->offset - 1;
3191 cluster->boundary[cluster->nr] = extent_key->objectid;
3192 cluster->nr++;
3193
3194 if (cluster->nr >= MAX_EXTENTS) {
3195 ret = relocate_file_extent_cluster(inode, cluster);
3196 if (ret)
3197 return ret;
3198 cluster->nr = 0;
3199 }
3200 return 0;
3201 }
3202
3203 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3204 static int get_ref_objectid_v0(struct reloc_control *rc,
3205 struct btrfs_path *path,
3206 struct btrfs_key *extent_key,
3207 u64 *ref_objectid, int *path_change)
3208 {
3209 struct btrfs_key key;
3210 struct extent_buffer *leaf;
3211 struct btrfs_extent_ref_v0 *ref0;
3212 int ret;
3213 int slot;
3214
3215 leaf = path->nodes[0];
3216 slot = path->slots[0];
3217 while (1) {
3218 if (slot >= btrfs_header_nritems(leaf)) {
3219 ret = btrfs_next_leaf(rc->extent_root, path);
3220 if (ret < 0)
3221 return ret;
3222 BUG_ON(ret > 0);
3223 leaf = path->nodes[0];
3224 slot = path->slots[0];
3225 if (path_change)
3226 *path_change = 1;
3227 }
3228 btrfs_item_key_to_cpu(leaf, &key, slot);
3229 if (key.objectid != extent_key->objectid)
3230 return -ENOENT;
3231
3232 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3233 slot++;
3234 continue;
3235 }
3236 ref0 = btrfs_item_ptr(leaf, slot,
3237 struct btrfs_extent_ref_v0);
3238 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3239 break;
3240 }
3241 return 0;
3242 }
3243 #endif
3244
3245 /*
3246 * helper to add a tree block to the list.
3247 * the major work is getting the generation and level of the block
3248 */
3249 static int add_tree_block(struct reloc_control *rc,
3250 struct btrfs_key *extent_key,
3251 struct btrfs_path *path,
3252 struct rb_root *blocks)
3253 {
3254 struct extent_buffer *eb;
3255 struct btrfs_extent_item *ei;
3256 struct btrfs_tree_block_info *bi;
3257 struct tree_block *block;
3258 struct rb_node *rb_node;
3259 u32 item_size;
3260 int level = -1;
3261 int generation;
3262
3263 eb = path->nodes[0];
3264 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3265
3266 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3267 item_size >= sizeof(*ei) + sizeof(*bi)) {
3268 ei = btrfs_item_ptr(eb, path->slots[0],
3269 struct btrfs_extent_item);
3270 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3271 bi = (struct btrfs_tree_block_info *)(ei + 1);
3272 level = btrfs_tree_block_level(eb, bi);
3273 } else {
3274 level = (int)extent_key->offset;
3275 }
3276 generation = btrfs_extent_generation(eb, ei);
3277 } else {
3278 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3279 u64 ref_owner;
3280 int ret;
3281
3282 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3283 ret = get_ref_objectid_v0(rc, path, extent_key,
3284 &ref_owner, NULL);
3285 if (ret < 0)
3286 return ret;
3287 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3288 level = (int)ref_owner;
3289 /* FIXME: get real generation */
3290 generation = 0;
3291 #else
3292 BUG();
3293 #endif
3294 }
3295
3296 btrfs_release_path(path);
3297
3298 BUG_ON(level == -1);
3299
3300 block = kmalloc(sizeof(*block), GFP_NOFS);
3301 if (!block)
3302 return -ENOMEM;
3303
3304 block->bytenr = extent_key->objectid;
3305 block->key.objectid = rc->extent_root->leafsize;
3306 block->key.offset = generation;
3307 block->level = level;
3308 block->key_ready = 0;
3309
3310 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3311 if (rb_node)
3312 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3313
3314 return 0;
3315 }
3316
3317 /*
3318 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3319 */
3320 static int __add_tree_block(struct reloc_control *rc,
3321 u64 bytenr, u32 blocksize,
3322 struct rb_root *blocks)
3323 {
3324 struct btrfs_path *path;
3325 struct btrfs_key key;
3326 int ret;
3327 bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info,
3328 SKINNY_METADATA);
3329
3330 if (tree_block_processed(bytenr, blocksize, rc))
3331 return 0;
3332
3333 if (tree_search(blocks, bytenr))
3334 return 0;
3335
3336 path = btrfs_alloc_path();
3337 if (!path)
3338 return -ENOMEM;
3339 again:
3340 key.objectid = bytenr;
3341 if (skinny) {
3342 key.type = BTRFS_METADATA_ITEM_KEY;
3343 key.offset = (u64)-1;
3344 } else {
3345 key.type = BTRFS_EXTENT_ITEM_KEY;
3346 key.offset = blocksize;
3347 }
3348
3349 path->search_commit_root = 1;
3350 path->skip_locking = 1;
3351 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3352 if (ret < 0)
3353 goto out;
3354
3355 if (ret > 0 && skinny) {
3356 if (path->slots[0]) {
3357 path->slots[0]--;
3358 btrfs_item_key_to_cpu(path->nodes[0], &key,
3359 path->slots[0]);
3360 if (key.objectid == bytenr &&
3361 (key.type == BTRFS_METADATA_ITEM_KEY ||
3362 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3363 key.offset == blocksize)))
3364 ret = 0;
3365 }
3366
3367 if (ret) {
3368 skinny = false;
3369 btrfs_release_path(path);
3370 goto again;
3371 }
3372 }
3373 BUG_ON(ret);
3374
3375 ret = add_tree_block(rc, &key, path, blocks);
3376 out:
3377 btrfs_free_path(path);
3378 return ret;
3379 }
3380
3381 /*
3382 * helper to check if the block use full backrefs for pointers in it
3383 */
3384 static int block_use_full_backref(struct reloc_control *rc,
3385 struct extent_buffer *eb)
3386 {
3387 u64 flags;
3388 int ret;
3389
3390 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3391 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3392 return 1;
3393
3394 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3395 eb->start, btrfs_header_level(eb), 1,
3396 NULL, &flags);
3397 BUG_ON(ret);
3398
3399 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3400 ret = 1;
3401 else
3402 ret = 0;
3403 return ret;
3404 }
3405
3406 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3407 struct inode *inode, u64 ino)
3408 {
3409 struct btrfs_key key;
3410 struct btrfs_path *path;
3411 struct btrfs_root *root = fs_info->tree_root;
3412 struct btrfs_trans_handle *trans;
3413 int ret = 0;
3414
3415 if (inode)
3416 goto truncate;
3417
3418 key.objectid = ino;
3419 key.type = BTRFS_INODE_ITEM_KEY;
3420 key.offset = 0;
3421
3422 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3423 if (IS_ERR(inode) || is_bad_inode(inode)) {
3424 if (!IS_ERR(inode))
3425 iput(inode);
3426 return -ENOENT;
3427 }
3428
3429 truncate:
3430 ret = btrfs_check_trunc_cache_free_space(root,
3431 &fs_info->global_block_rsv);
3432 if (ret)
3433 goto out;
3434
3435 path = btrfs_alloc_path();
3436 if (!path) {
3437 ret = -ENOMEM;
3438 goto out;
3439 }
3440
3441 trans = btrfs_join_transaction(root);
3442 if (IS_ERR(trans)) {
3443 btrfs_free_path(path);
3444 ret = PTR_ERR(trans);
3445 goto out;
3446 }
3447
3448 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
3449
3450 btrfs_free_path(path);
3451 btrfs_end_transaction(trans, root);
3452 btrfs_btree_balance_dirty(root);
3453 out:
3454 iput(inode);
3455 return ret;
3456 }
3457
3458 /*
3459 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3460 * this function scans fs tree to find blocks reference the data extent
3461 */
3462 static int find_data_references(struct reloc_control *rc,
3463 struct btrfs_key *extent_key,
3464 struct extent_buffer *leaf,
3465 struct btrfs_extent_data_ref *ref,
3466 struct rb_root *blocks)
3467 {
3468 struct btrfs_path *path;
3469 struct tree_block *block;
3470 struct btrfs_root *root;
3471 struct btrfs_file_extent_item *fi;
3472 struct rb_node *rb_node;
3473 struct btrfs_key key;
3474 u64 ref_root;
3475 u64 ref_objectid;
3476 u64 ref_offset;
3477 u32 ref_count;
3478 u32 nritems;
3479 int err = 0;
3480 int added = 0;
3481 int counted;
3482 int ret;
3483
3484 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3485 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3486 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3487 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3488
3489 /*
3490 * This is an extent belonging to the free space cache, lets just delete
3491 * it and redo the search.
3492 */
3493 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3494 ret = delete_block_group_cache(rc->extent_root->fs_info,
3495 NULL, ref_objectid);
3496 if (ret != -ENOENT)
3497 return ret;
3498 ret = 0;
3499 }
3500
3501 path = btrfs_alloc_path();
3502 if (!path)
3503 return -ENOMEM;
3504 path->reada = 1;
3505
3506 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3507 if (IS_ERR(root)) {
3508 err = PTR_ERR(root);
3509 goto out;
3510 }
3511
3512 key.objectid = ref_objectid;
3513 key.type = BTRFS_EXTENT_DATA_KEY;
3514 if (ref_offset > ((u64)-1 << 32))
3515 key.offset = 0;
3516 else
3517 key.offset = ref_offset;
3518
3519 path->search_commit_root = 1;
3520 path->skip_locking = 1;
3521 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3522 if (ret < 0) {
3523 err = ret;
3524 goto out;
3525 }
3526
3527 leaf = path->nodes[0];
3528 nritems = btrfs_header_nritems(leaf);
3529 /*
3530 * the references in tree blocks that use full backrefs
3531 * are not counted in
3532 */
3533 if (block_use_full_backref(rc, leaf))
3534 counted = 0;
3535 else
3536 counted = 1;
3537 rb_node = tree_search(blocks, leaf->start);
3538 if (rb_node) {
3539 if (counted)
3540 added = 1;
3541 else
3542 path->slots[0] = nritems;
3543 }
3544
3545 while (ref_count > 0) {
3546 while (path->slots[0] >= nritems) {
3547 ret = btrfs_next_leaf(root, path);
3548 if (ret < 0) {
3549 err = ret;
3550 goto out;
3551 }
3552 if (ret > 0) {
3553 WARN_ON(1);
3554 goto out;
3555 }
3556
3557 leaf = path->nodes[0];
3558 nritems = btrfs_header_nritems(leaf);
3559 added = 0;
3560
3561 if (block_use_full_backref(rc, leaf))
3562 counted = 0;
3563 else
3564 counted = 1;
3565 rb_node = tree_search(blocks, leaf->start);
3566 if (rb_node) {
3567 if (counted)
3568 added = 1;
3569 else
3570 path->slots[0] = nritems;
3571 }
3572 }
3573
3574 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3575 if (key.objectid != ref_objectid ||
3576 key.type != BTRFS_EXTENT_DATA_KEY) {
3577 WARN_ON(1);
3578 break;
3579 }
3580
3581 fi = btrfs_item_ptr(leaf, path->slots[0],
3582 struct btrfs_file_extent_item);
3583
3584 if (btrfs_file_extent_type(leaf, fi) ==
3585 BTRFS_FILE_EXTENT_INLINE)
3586 goto next;
3587
3588 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3589 extent_key->objectid)
3590 goto next;
3591
3592 key.offset -= btrfs_file_extent_offset(leaf, fi);
3593 if (key.offset != ref_offset)
3594 goto next;
3595
3596 if (counted)
3597 ref_count--;
3598 if (added)
3599 goto next;
3600
3601 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3602 block = kmalloc(sizeof(*block), GFP_NOFS);
3603 if (!block) {
3604 err = -ENOMEM;
3605 break;
3606 }
3607 block->bytenr = leaf->start;
3608 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3609 block->level = 0;
3610 block->key_ready = 1;
3611 rb_node = tree_insert(blocks, block->bytenr,
3612 &block->rb_node);
3613 if (rb_node)
3614 backref_tree_panic(rb_node, -EEXIST,
3615 block->bytenr);
3616 }
3617 if (counted)
3618 added = 1;
3619 else
3620 path->slots[0] = nritems;
3621 next:
3622 path->slots[0]++;
3623
3624 }
3625 out:
3626 btrfs_free_path(path);
3627 return err;
3628 }
3629
3630 /*
3631 * helper to find all tree blocks that reference a given data extent
3632 */
3633 static noinline_for_stack
3634 int add_data_references(struct reloc_control *rc,
3635 struct btrfs_key *extent_key,
3636 struct btrfs_path *path,
3637 struct rb_root *blocks)
3638 {
3639 struct btrfs_key key;
3640 struct extent_buffer *eb;
3641 struct btrfs_extent_data_ref *dref;
3642 struct btrfs_extent_inline_ref *iref;
3643 unsigned long ptr;
3644 unsigned long end;
3645 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3646 int ret = 0;
3647 int err = 0;
3648
3649 eb = path->nodes[0];
3650 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3651 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3652 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3653 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3654 ptr = end;
3655 else
3656 #endif
3657 ptr += sizeof(struct btrfs_extent_item);
3658
3659 while (ptr < end) {
3660 iref = (struct btrfs_extent_inline_ref *)ptr;
3661 key.type = btrfs_extent_inline_ref_type(eb, iref);
3662 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3663 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3664 ret = __add_tree_block(rc, key.offset, blocksize,
3665 blocks);
3666 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3667 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3668 ret = find_data_references(rc, extent_key,
3669 eb, dref, blocks);
3670 } else {
3671 BUG();
3672 }
3673 if (ret) {
3674 err = ret;
3675 goto out;
3676 }
3677 ptr += btrfs_extent_inline_ref_size(key.type);
3678 }
3679 WARN_ON(ptr > end);
3680
3681 while (1) {
3682 cond_resched();
3683 eb = path->nodes[0];
3684 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3685 ret = btrfs_next_leaf(rc->extent_root, path);
3686 if (ret < 0) {
3687 err = ret;
3688 break;
3689 }
3690 if (ret > 0)
3691 break;
3692 eb = path->nodes[0];
3693 }
3694
3695 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3696 if (key.objectid != extent_key->objectid)
3697 break;
3698
3699 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3700 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3701 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3702 #else
3703 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3704 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3705 #endif
3706 ret = __add_tree_block(rc, key.offset, blocksize,
3707 blocks);
3708 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3709 dref = btrfs_item_ptr(eb, path->slots[0],
3710 struct btrfs_extent_data_ref);
3711 ret = find_data_references(rc, extent_key,
3712 eb, dref, blocks);
3713 } else {
3714 ret = 0;
3715 }
3716 if (ret) {
3717 err = ret;
3718 break;
3719 }
3720 path->slots[0]++;
3721 }
3722 out:
3723 btrfs_release_path(path);
3724 if (err)
3725 free_block_list(blocks);
3726 return err;
3727 }
3728
3729 /*
3730 * helper to find next unprocessed extent
3731 */
3732 static noinline_for_stack
3733 int find_next_extent(struct btrfs_trans_handle *trans,
3734 struct reloc_control *rc, struct btrfs_path *path,
3735 struct btrfs_key *extent_key)
3736 {
3737 struct btrfs_key key;
3738 struct extent_buffer *leaf;
3739 u64 start, end, last;
3740 int ret;
3741
3742 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3743 while (1) {
3744 cond_resched();
3745 if (rc->search_start >= last) {
3746 ret = 1;
3747 break;
3748 }
3749
3750 key.objectid = rc->search_start;
3751 key.type = BTRFS_EXTENT_ITEM_KEY;
3752 key.offset = 0;
3753
3754 path->search_commit_root = 1;
3755 path->skip_locking = 1;
3756 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3757 0, 0);
3758 if (ret < 0)
3759 break;
3760 next:
3761 leaf = path->nodes[0];
3762 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3763 ret = btrfs_next_leaf(rc->extent_root, path);
3764 if (ret != 0)
3765 break;
3766 leaf = path->nodes[0];
3767 }
3768
3769 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3770 if (key.objectid >= last) {
3771 ret = 1;
3772 break;
3773 }
3774
3775 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3776 key.type != BTRFS_METADATA_ITEM_KEY) {
3777 path->slots[0]++;
3778 goto next;
3779 }
3780
3781 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3782 key.objectid + key.offset <= rc->search_start) {
3783 path->slots[0]++;
3784 goto next;
3785 }
3786
3787 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3788 key.objectid + rc->extent_root->leafsize <=
3789 rc->search_start) {
3790 path->slots[0]++;
3791 goto next;
3792 }
3793
3794 ret = find_first_extent_bit(&rc->processed_blocks,
3795 key.objectid, &start, &end,
3796 EXTENT_DIRTY, NULL);
3797
3798 if (ret == 0 && start <= key.objectid) {
3799 btrfs_release_path(path);
3800 rc->search_start = end + 1;
3801 } else {
3802 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3803 rc->search_start = key.objectid + key.offset;
3804 else
3805 rc->search_start = key.objectid +
3806 rc->extent_root->leafsize;
3807 memcpy(extent_key, &key, sizeof(key));
3808 return 0;
3809 }
3810 }
3811 btrfs_release_path(path);
3812 return ret;
3813 }
3814
3815 static void set_reloc_control(struct reloc_control *rc)
3816 {
3817 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3818
3819 mutex_lock(&fs_info->reloc_mutex);
3820 fs_info->reloc_ctl = rc;
3821 mutex_unlock(&fs_info->reloc_mutex);
3822 }
3823
3824 static void unset_reloc_control(struct reloc_control *rc)
3825 {
3826 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3827
3828 mutex_lock(&fs_info->reloc_mutex);
3829 fs_info->reloc_ctl = NULL;
3830 mutex_unlock(&fs_info->reloc_mutex);
3831 }
3832
3833 static int check_extent_flags(u64 flags)
3834 {
3835 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3836 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3837 return 1;
3838 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3839 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3840 return 1;
3841 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3842 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3843 return 1;
3844 return 0;
3845 }
3846
3847 static noinline_for_stack
3848 int prepare_to_relocate(struct reloc_control *rc)
3849 {
3850 struct btrfs_trans_handle *trans;
3851 int ret;
3852
3853 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3854 BTRFS_BLOCK_RSV_TEMP);
3855 if (!rc->block_rsv)
3856 return -ENOMEM;
3857
3858 /*
3859 * reserve some space for creating reloc trees.
3860 * btrfs_init_reloc_root will use them when there
3861 * is no reservation in transaction handle.
3862 */
3863 ret = btrfs_block_rsv_add(rc->extent_root, rc->block_rsv,
3864 rc->extent_root->nodesize * 256,
3865 BTRFS_RESERVE_FLUSH_ALL);
3866 if (ret)
3867 return ret;
3868
3869 memset(&rc->cluster, 0, sizeof(rc->cluster));
3870 rc->search_start = rc->block_group->key.objectid;
3871 rc->extents_found = 0;
3872 rc->nodes_relocated = 0;
3873 rc->merging_rsv_size = 0;
3874
3875 rc->create_reloc_tree = 1;
3876 set_reloc_control(rc);
3877
3878 trans = btrfs_join_transaction(rc->extent_root);
3879 if (IS_ERR(trans)) {
3880 unset_reloc_control(rc);
3881 /*
3882 * extent tree is not a ref_cow tree and has no reloc_root to
3883 * cleanup. And callers are responsible to free the above
3884 * block rsv.
3885 */
3886 return PTR_ERR(trans);
3887 }
3888 btrfs_commit_transaction(trans, rc->extent_root);
3889 return 0;
3890 }
3891
3892 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3893 {
3894 struct rb_root blocks = RB_ROOT;
3895 struct btrfs_key key;
3896 struct btrfs_trans_handle *trans = NULL;
3897 struct btrfs_path *path;
3898 struct btrfs_extent_item *ei;
3899 u64 flags;
3900 u32 item_size;
3901 int ret;
3902 int err = 0;
3903 int progress = 0;
3904
3905 path = btrfs_alloc_path();
3906 if (!path)
3907 return -ENOMEM;
3908 path->reada = 1;
3909
3910 ret = prepare_to_relocate(rc);
3911 if (ret) {
3912 err = ret;
3913 goto out_free;
3914 }
3915
3916 while (1) {
3917 progress++;
3918 trans = btrfs_start_transaction(rc->extent_root, 0);
3919 if (IS_ERR(trans)) {
3920 err = PTR_ERR(trans);
3921 trans = NULL;
3922 break;
3923 }
3924 restart:
3925 if (update_backref_cache(trans, &rc->backref_cache)) {
3926 btrfs_end_transaction(trans, rc->extent_root);
3927 continue;
3928 }
3929
3930 ret = find_next_extent(trans, rc, path, &key);
3931 if (ret < 0)
3932 err = ret;
3933 if (ret != 0)
3934 break;
3935
3936 rc->extents_found++;
3937
3938 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3939 struct btrfs_extent_item);
3940 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3941 if (item_size >= sizeof(*ei)) {
3942 flags = btrfs_extent_flags(path->nodes[0], ei);
3943 ret = check_extent_flags(flags);
3944 BUG_ON(ret);
3945
3946 } else {
3947 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3948 u64 ref_owner;
3949 int path_change = 0;
3950
3951 BUG_ON(item_size !=
3952 sizeof(struct btrfs_extent_item_v0));
3953 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3954 &path_change);
3955 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3956 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3957 else
3958 flags = BTRFS_EXTENT_FLAG_DATA;
3959
3960 if (path_change) {
3961 btrfs_release_path(path);
3962
3963 path->search_commit_root = 1;
3964 path->skip_locking = 1;
3965 ret = btrfs_search_slot(NULL, rc->extent_root,
3966 &key, path, 0, 0);
3967 if (ret < 0) {
3968 err = ret;
3969 break;
3970 }
3971 BUG_ON(ret > 0);
3972 }
3973 #else
3974 BUG();
3975 #endif
3976 }
3977
3978 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3979 ret = add_tree_block(rc, &key, path, &blocks);
3980 } else if (rc->stage == UPDATE_DATA_PTRS &&
3981 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3982 ret = add_data_references(rc, &key, path, &blocks);
3983 } else {
3984 btrfs_release_path(path);
3985 ret = 0;
3986 }
3987 if (ret < 0) {
3988 err = ret;
3989 break;
3990 }
3991
3992 if (!RB_EMPTY_ROOT(&blocks)) {
3993 ret = relocate_tree_blocks(trans, rc, &blocks);
3994 if (ret < 0) {
3995 if (ret != -EAGAIN) {
3996 err = ret;
3997 break;
3998 }
3999 rc->extents_found--;
4000 rc->search_start = key.objectid;
4001 }
4002 }
4003
4004 ret = btrfs_block_rsv_check(rc->extent_root, rc->block_rsv, 5);
4005 if (ret < 0) {
4006 if (ret != -ENOSPC) {
4007 err = ret;
4008 WARN_ON(1);
4009 break;
4010 }
4011 rc->commit_transaction = 1;
4012 }
4013
4014 if (rc->commit_transaction) {
4015 rc->commit_transaction = 0;
4016 ret = btrfs_commit_transaction(trans, rc->extent_root);
4017 BUG_ON(ret);
4018 } else {
4019 btrfs_end_transaction_throttle(trans, rc->extent_root);
4020 btrfs_btree_balance_dirty(rc->extent_root);
4021 }
4022 trans = NULL;
4023
4024 if (rc->stage == MOVE_DATA_EXTENTS &&
4025 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4026 rc->found_file_extent = 1;
4027 ret = relocate_data_extent(rc->data_inode,
4028 &key, &rc->cluster);
4029 if (ret < 0) {
4030 err = ret;
4031 break;
4032 }
4033 }
4034 }
4035 if (trans && progress && err == -ENOSPC) {
4036 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
4037 rc->block_group->flags);
4038 if (ret == 0) {
4039 err = 0;
4040 progress = 0;
4041 goto restart;
4042 }
4043 }
4044
4045 btrfs_release_path(path);
4046 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
4047 GFP_NOFS);
4048
4049 if (trans) {
4050 btrfs_end_transaction_throttle(trans, rc->extent_root);
4051 btrfs_btree_balance_dirty(rc->extent_root);
4052 }
4053
4054 if (!err) {
4055 ret = relocate_file_extent_cluster(rc->data_inode,
4056 &rc->cluster);
4057 if (ret < 0)
4058 err = ret;
4059 }
4060
4061 rc->create_reloc_tree = 0;
4062 set_reloc_control(rc);
4063
4064 backref_cache_cleanup(&rc->backref_cache);
4065 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4066
4067 err = prepare_to_merge(rc, err);
4068
4069 merge_reloc_roots(rc);
4070
4071 rc->merge_reloc_tree = 0;
4072 unset_reloc_control(rc);
4073 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4074
4075 /* get rid of pinned extents */
4076 trans = btrfs_join_transaction(rc->extent_root);
4077 if (IS_ERR(trans))
4078 err = PTR_ERR(trans);
4079 else
4080 btrfs_commit_transaction(trans, rc->extent_root);
4081 out_free:
4082 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
4083 btrfs_free_path(path);
4084 return err;
4085 }
4086
4087 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4088 struct btrfs_root *root, u64 objectid)
4089 {
4090 struct btrfs_path *path;
4091 struct btrfs_inode_item *item;
4092 struct extent_buffer *leaf;
4093 int ret;
4094
4095 path = btrfs_alloc_path();
4096 if (!path)
4097 return -ENOMEM;
4098
4099 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4100 if (ret)
4101 goto out;
4102
4103 leaf = path->nodes[0];
4104 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4105 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4106 btrfs_set_inode_generation(leaf, item, 1);
4107 btrfs_set_inode_size(leaf, item, 0);
4108 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4109 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4110 BTRFS_INODE_PREALLOC);
4111 btrfs_mark_buffer_dirty(leaf);
4112 btrfs_release_path(path);
4113 out:
4114 btrfs_free_path(path);
4115 return ret;
4116 }
4117
4118 /*
4119 * helper to create inode for data relocation.
4120 * the inode is in data relocation tree and its link count is 0
4121 */
4122 static noinline_for_stack
4123 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4124 struct btrfs_block_group_cache *group)
4125 {
4126 struct inode *inode = NULL;
4127 struct btrfs_trans_handle *trans;
4128 struct btrfs_root *root;
4129 struct btrfs_key key;
4130 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
4131 int err = 0;
4132
4133 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4134 if (IS_ERR(root))
4135 return ERR_CAST(root);
4136
4137 trans = btrfs_start_transaction(root, 6);
4138 if (IS_ERR(trans))
4139 return ERR_CAST(trans);
4140
4141 err = btrfs_find_free_objectid(root, &objectid);
4142 if (err)
4143 goto out;
4144
4145 err = __insert_orphan_inode(trans, root, objectid);
4146 BUG_ON(err);
4147
4148 key.objectid = objectid;
4149 key.type = BTRFS_INODE_ITEM_KEY;
4150 key.offset = 0;
4151 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
4152 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4153 BTRFS_I(inode)->index_cnt = group->key.objectid;
4154
4155 err = btrfs_orphan_add(trans, inode);
4156 out:
4157 btrfs_end_transaction(trans, root);
4158 btrfs_btree_balance_dirty(root);
4159 if (err) {
4160 if (inode)
4161 iput(inode);
4162 inode = ERR_PTR(err);
4163 }
4164 return inode;
4165 }
4166
4167 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4168 {
4169 struct reloc_control *rc;
4170
4171 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4172 if (!rc)
4173 return NULL;
4174
4175 INIT_LIST_HEAD(&rc->reloc_roots);
4176 backref_cache_init(&rc->backref_cache);
4177 mapping_tree_init(&rc->reloc_root_tree);
4178 extent_io_tree_init(&rc->processed_blocks,
4179 fs_info->btree_inode->i_mapping);
4180 return rc;
4181 }
4182
4183 /*
4184 * function to relocate all extents in a block group.
4185 */
4186 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4187 {
4188 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4189 struct reloc_control *rc;
4190 struct inode *inode;
4191 struct btrfs_path *path;
4192 int ret;
4193 int rw = 0;
4194 int err = 0;
4195
4196 rc = alloc_reloc_control(fs_info);
4197 if (!rc)
4198 return -ENOMEM;
4199
4200 rc->extent_root = extent_root;
4201
4202 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4203 BUG_ON(!rc->block_group);
4204
4205 if (!rc->block_group->ro) {
4206 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
4207 if (ret) {
4208 err = ret;
4209 goto out;
4210 }
4211 rw = 1;
4212 }
4213
4214 path = btrfs_alloc_path();
4215 if (!path) {
4216 err = -ENOMEM;
4217 goto out;
4218 }
4219
4220 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4221 path);
4222 btrfs_free_path(path);
4223
4224 if (!IS_ERR(inode))
4225 ret = delete_block_group_cache(fs_info, inode, 0);
4226 else
4227 ret = PTR_ERR(inode);
4228
4229 if (ret && ret != -ENOENT) {
4230 err = ret;
4231 goto out;
4232 }
4233
4234 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4235 if (IS_ERR(rc->data_inode)) {
4236 err = PTR_ERR(rc->data_inode);
4237 rc->data_inode = NULL;
4238 goto out;
4239 }
4240
4241 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
4242 rc->block_group->key.objectid, rc->block_group->flags);
4243
4244 ret = btrfs_start_all_delalloc_inodes(fs_info, 0);
4245 if (ret < 0) {
4246 err = ret;
4247 goto out;
4248 }
4249 btrfs_wait_all_ordered_extents(fs_info);
4250
4251 while (1) {
4252 mutex_lock(&fs_info->cleaner_mutex);
4253 ret = relocate_block_group(rc);
4254 mutex_unlock(&fs_info->cleaner_mutex);
4255 if (ret < 0) {
4256 err = ret;
4257 goto out;
4258 }
4259
4260 if (rc->extents_found == 0)
4261 break;
4262
4263 printk(KERN_INFO "btrfs: found %llu extents\n",
4264 rc->extents_found);
4265
4266 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4267 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
4268 invalidate_mapping_pages(rc->data_inode->i_mapping,
4269 0, -1);
4270 rc->stage = UPDATE_DATA_PTRS;
4271 }
4272 }
4273
4274 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
4275 rc->block_group->key.objectid,
4276 rc->block_group->key.objectid +
4277 rc->block_group->key.offset - 1);
4278
4279 WARN_ON(rc->block_group->pinned > 0);
4280 WARN_ON(rc->block_group->reserved > 0);
4281 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4282 out:
4283 if (err && rw)
4284 btrfs_set_block_group_rw(extent_root, rc->block_group);
4285 iput(rc->data_inode);
4286 btrfs_put_block_group(rc->block_group);
4287 kfree(rc);
4288 return err;
4289 }
4290
4291 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4292 {
4293 struct btrfs_trans_handle *trans;
4294 int ret, err;
4295
4296 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4297 if (IS_ERR(trans))
4298 return PTR_ERR(trans);
4299
4300 memset(&root->root_item.drop_progress, 0,
4301 sizeof(root->root_item.drop_progress));
4302 root->root_item.drop_level = 0;
4303 btrfs_set_root_refs(&root->root_item, 0);
4304 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4305 &root->root_key, &root->root_item);
4306
4307 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4308 if (err)
4309 return err;
4310 return ret;
4311 }
4312
4313 /*
4314 * recover relocation interrupted by system crash.
4315 *
4316 * this function resumes merging reloc trees with corresponding fs trees.
4317 * this is important for keeping the sharing of tree blocks
4318 */
4319 int btrfs_recover_relocation(struct btrfs_root *root)
4320 {
4321 LIST_HEAD(reloc_roots);
4322 struct btrfs_key key;
4323 struct btrfs_root *fs_root;
4324 struct btrfs_root *reloc_root;
4325 struct btrfs_path *path;
4326 struct extent_buffer *leaf;
4327 struct reloc_control *rc = NULL;
4328 struct btrfs_trans_handle *trans;
4329 int ret;
4330 int err = 0;
4331
4332 path = btrfs_alloc_path();
4333 if (!path)
4334 return -ENOMEM;
4335 path->reada = -1;
4336
4337 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4338 key.type = BTRFS_ROOT_ITEM_KEY;
4339 key.offset = (u64)-1;
4340
4341 while (1) {
4342 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4343 path, 0, 0);
4344 if (ret < 0) {
4345 err = ret;
4346 goto out;
4347 }
4348 if (ret > 0) {
4349 if (path->slots[0] == 0)
4350 break;
4351 path->slots[0]--;
4352 }
4353 leaf = path->nodes[0];
4354 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4355 btrfs_release_path(path);
4356
4357 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4358 key.type != BTRFS_ROOT_ITEM_KEY)
4359 break;
4360
4361 reloc_root = btrfs_read_fs_root(root, &key);
4362 if (IS_ERR(reloc_root)) {
4363 err = PTR_ERR(reloc_root);
4364 goto out;
4365 }
4366
4367 list_add(&reloc_root->root_list, &reloc_roots);
4368
4369 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4370 fs_root = read_fs_root(root->fs_info,
4371 reloc_root->root_key.offset);
4372 if (IS_ERR(fs_root)) {
4373 ret = PTR_ERR(fs_root);
4374 if (ret != -ENOENT) {
4375 err = ret;
4376 goto out;
4377 }
4378 ret = mark_garbage_root(reloc_root);
4379 if (ret < 0) {
4380 err = ret;
4381 goto out;
4382 }
4383 }
4384 }
4385
4386 if (key.offset == 0)
4387 break;
4388
4389 key.offset--;
4390 }
4391 btrfs_release_path(path);
4392
4393 if (list_empty(&reloc_roots))
4394 goto out;
4395
4396 rc = alloc_reloc_control(root->fs_info);
4397 if (!rc) {
4398 err = -ENOMEM;
4399 goto out;
4400 }
4401
4402 rc->extent_root = root->fs_info->extent_root;
4403
4404 set_reloc_control(rc);
4405
4406 trans = btrfs_join_transaction(rc->extent_root);
4407 if (IS_ERR(trans)) {
4408 unset_reloc_control(rc);
4409 err = PTR_ERR(trans);
4410 goto out_free;
4411 }
4412
4413 rc->merge_reloc_tree = 1;
4414
4415 while (!list_empty(&reloc_roots)) {
4416 reloc_root = list_entry(reloc_roots.next,
4417 struct btrfs_root, root_list);
4418 list_del(&reloc_root->root_list);
4419
4420 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4421 list_add_tail(&reloc_root->root_list,
4422 &rc->reloc_roots);
4423 continue;
4424 }
4425
4426 fs_root = read_fs_root(root->fs_info,
4427 reloc_root->root_key.offset);
4428 if (IS_ERR(fs_root)) {
4429 err = PTR_ERR(fs_root);
4430 goto out_free;
4431 }
4432
4433 err = __add_reloc_root(reloc_root);
4434 BUG_ON(err < 0); /* -ENOMEM or logic error */
4435 fs_root->reloc_root = reloc_root;
4436 }
4437
4438 err = btrfs_commit_transaction(trans, rc->extent_root);
4439 if (err)
4440 goto out_free;
4441
4442 merge_reloc_roots(rc);
4443
4444 unset_reloc_control(rc);
4445
4446 trans = btrfs_join_transaction(rc->extent_root);
4447 if (IS_ERR(trans))
4448 err = PTR_ERR(trans);
4449 else
4450 err = btrfs_commit_transaction(trans, rc->extent_root);
4451 out_free:
4452 kfree(rc);
4453 out:
4454 if (!list_empty(&reloc_roots))
4455 free_reloc_roots(&reloc_roots);
4456
4457 btrfs_free_path(path);
4458
4459 if (err == 0) {
4460 /* cleanup orphan inode in data relocation tree */
4461 fs_root = read_fs_root(root->fs_info,
4462 BTRFS_DATA_RELOC_TREE_OBJECTID);
4463 if (IS_ERR(fs_root))
4464 err = PTR_ERR(fs_root);
4465 else
4466 err = btrfs_orphan_cleanup(fs_root);
4467 }
4468 return err;
4469 }
4470
4471 /*
4472 * helper to add ordered checksum for data relocation.
4473 *
4474 * cloning checksum properly handles the nodatasum extents.
4475 * it also saves CPU time to re-calculate the checksum.
4476 */
4477 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4478 {
4479 struct btrfs_ordered_sum *sums;
4480 struct btrfs_ordered_extent *ordered;
4481 struct btrfs_root *root = BTRFS_I(inode)->root;
4482 int ret;
4483 u64 disk_bytenr;
4484 u64 new_bytenr;
4485 LIST_HEAD(list);
4486
4487 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4488 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4489
4490 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4491 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4492 disk_bytenr + len - 1, &list, 0);
4493 if (ret)
4494 goto out;
4495
4496 while (!list_empty(&list)) {
4497 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4498 list_del_init(&sums->list);
4499
4500 /*
4501 * We need to offset the new_bytenr based on where the csum is.
4502 * We need to do this because we will read in entire prealloc
4503 * extents but we may have written to say the middle of the
4504 * prealloc extent, so we need to make sure the csum goes with
4505 * the right disk offset.
4506 *
4507 * We can do this because the data reloc inode refers strictly
4508 * to the on disk bytes, so we don't have to worry about
4509 * disk_len vs real len like with real inodes since it's all
4510 * disk length.
4511 */
4512 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4513 sums->bytenr = new_bytenr;
4514
4515 btrfs_add_ordered_sum(inode, ordered, sums);
4516 }
4517 out:
4518 btrfs_put_ordered_extent(ordered);
4519 return ret;
4520 }
4521
4522 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4523 struct btrfs_root *root, struct extent_buffer *buf,
4524 struct extent_buffer *cow)
4525 {
4526 struct reloc_control *rc;
4527 struct backref_node *node;
4528 int first_cow = 0;
4529 int level;
4530 int ret = 0;
4531
4532 rc = root->fs_info->reloc_ctl;
4533 if (!rc)
4534 return 0;
4535
4536 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4537 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4538
4539 level = btrfs_header_level(buf);
4540 if (btrfs_header_generation(buf) <=
4541 btrfs_root_last_snapshot(&root->root_item))
4542 first_cow = 1;
4543
4544 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4545 rc->create_reloc_tree) {
4546 WARN_ON(!first_cow && level == 0);
4547
4548 node = rc->backref_cache.path[level];
4549 BUG_ON(node->bytenr != buf->start &&
4550 node->new_bytenr != buf->start);
4551
4552 drop_node_buffer(node);
4553 extent_buffer_get(cow);
4554 node->eb = cow;
4555 node->new_bytenr = cow->start;
4556
4557 if (!node->pending) {
4558 list_move_tail(&node->list,
4559 &rc->backref_cache.pending[level]);
4560 node->pending = 1;
4561 }
4562
4563 if (first_cow)
4564 __mark_block_processed(rc, node);
4565
4566 if (first_cow && level > 0)
4567 rc->nodes_relocated += buf->len;
4568 }
4569
4570 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4571 ret = replace_file_extents(trans, rc, root, cow);
4572 return ret;
4573 }
4574
4575 /*
4576 * called before creating snapshot. it calculates metadata reservation
4577 * requried for relocating tree blocks in the snapshot
4578 */
4579 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4580 struct btrfs_pending_snapshot *pending,
4581 u64 *bytes_to_reserve)
4582 {
4583 struct btrfs_root *root;
4584 struct reloc_control *rc;
4585
4586 root = pending->root;
4587 if (!root->reloc_root)
4588 return;
4589
4590 rc = root->fs_info->reloc_ctl;
4591 if (!rc->merge_reloc_tree)
4592 return;
4593
4594 root = root->reloc_root;
4595 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4596 /*
4597 * relocation is in the stage of merging trees. the space
4598 * used by merging a reloc tree is twice the size of
4599 * relocated tree nodes in the worst case. half for cowing
4600 * the reloc tree, half for cowing the fs tree. the space
4601 * used by cowing the reloc tree will be freed after the
4602 * tree is dropped. if we create snapshot, cowing the fs
4603 * tree may use more space than it frees. so we need
4604 * reserve extra space.
4605 */
4606 *bytes_to_reserve += rc->nodes_relocated;
4607 }
4608
4609 /*
4610 * called after snapshot is created. migrate block reservation
4611 * and create reloc root for the newly created snapshot
4612 */
4613 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4614 struct btrfs_pending_snapshot *pending)
4615 {
4616 struct btrfs_root *root = pending->root;
4617 struct btrfs_root *reloc_root;
4618 struct btrfs_root *new_root;
4619 struct reloc_control *rc;
4620 int ret;
4621
4622 if (!root->reloc_root)
4623 return 0;
4624
4625 rc = root->fs_info->reloc_ctl;
4626 rc->merging_rsv_size += rc->nodes_relocated;
4627
4628 if (rc->merge_reloc_tree) {
4629 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4630 rc->block_rsv,
4631 rc->nodes_relocated);
4632 if (ret)
4633 return ret;
4634 }
4635
4636 new_root = pending->snap;
4637 reloc_root = create_reloc_root(trans, root->reloc_root,
4638 new_root->root_key.objectid);
4639 if (IS_ERR(reloc_root))
4640 return PTR_ERR(reloc_root);
4641
4642 ret = __add_reloc_root(reloc_root);
4643 BUG_ON(ret < 0);
4644 new_root->reloc_root = reloc_root;
4645
4646 if (rc->create_reloc_tree)
4647 ret = clone_backref_node(trans, rc, root, reloc_root);
4648 return ret;
4649 }
Linux with added FPC-III support