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