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staging: hv: update dist release parsing in hv_kvp_daemon
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / btrfs / relocation.c
blob58250e09eb056213944db6703d78679fbb94d35f
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
34 /*
35 * backref_node, mapping_node and tree_block start with this
36 */
37 struct tree_entry {
38 struct rb_node rb_node;
39 u64 bytenr;
40 };
41
42 /*
43 * present a tree block in the backref cache
44 */
45 struct backref_node {
46 struct rb_node rb_node;
47 u64 bytenr;
48
49 u64 new_bytenr;
50 /* objectid of tree block owner, can be not uptodate */
51 u64 owner;
52 /* link to pending, changed or detached list */
53 struct list_head list;
54 /* list of upper level blocks reference this block */
55 struct list_head upper;
56 /* list of child blocks in the cache */
57 struct list_head lower;
58 /* NULL if this node is not tree root */
59 struct btrfs_root *root;
60 /* extent buffer got by COW the block */
61 struct extent_buffer *eb;
62 /* level of tree block */
63 unsigned int level:8;
64 /* is the block in non-reference counted tree */
65 unsigned int cowonly:1;
66 /* 1 if no child node in the cache */
67 unsigned int lowest:1;
68 /* is the extent buffer locked */
69 unsigned int locked:1;
70 /* has the block been processed */
71 unsigned int processed:1;
72 /* have backrefs of this block been checked */
73 unsigned int checked:1;
74 /*
75 * 1 if corresponding block has been cowed but some upper
76 * level block pointers may not point to the new location
77 */
78 unsigned int pending:1;
79 /*
80 * 1 if the backref node isn't connected to any other
81 * backref node.
82 */
83 unsigned int detached:1;
84 };
85
86 /*
87 * present a block pointer in the backref cache
88 */
89 struct backref_edge {
90 struct list_head list[2];
91 struct backref_node *node[2];
92 };
93
94 #define LOWER 0
95 #define UPPER 1
96
97 struct backref_cache {
98 /* red black tree of all backref nodes in the cache */
99 struct rb_root rb_root;
100 /* for passing backref nodes to btrfs_reloc_cow_block */
101 struct backref_node *path[BTRFS_MAX_LEVEL];
102 /*
103 * list of blocks that have been cowed but some block
104 * pointers in upper level blocks may not reflect the
105 * new location
106 */
107 struct list_head pending[BTRFS_MAX_LEVEL];
108 /* list of backref nodes with no child node */
109 struct list_head leaves;
110 /* list of blocks that have been cowed in current transaction */
111 struct list_head changed;
112 /* list of detached backref node. */
113 struct list_head detached;
114
115 u64 last_trans;
116
117 int nr_nodes;
118 int nr_edges;
119 };
120
121 /*
122 * map address of tree root to tree
123 */
124 struct mapping_node {
125 struct rb_node rb_node;
126 u64 bytenr;
127 void *data;
128 };
129
130 struct mapping_tree {
131 struct rb_root rb_root;
132 spinlock_t lock;
133 };
134
135 /*
136 * present a tree block to process
137 */
138 struct tree_block {
139 struct rb_node rb_node;
140 u64 bytenr;
141 struct btrfs_key key;
142 unsigned int level:8;
143 unsigned int key_ready:1;
144 };
145
146 #define MAX_EXTENTS 128
147
148 struct file_extent_cluster {
149 u64 start;
150 u64 end;
151 u64 boundary[MAX_EXTENTS];
152 unsigned int nr;
153 };
154
155 struct reloc_control {
156 /* block group to relocate */
157 struct btrfs_block_group_cache *block_group;
158 /* extent tree */
159 struct btrfs_root *extent_root;
160 /* inode for moving data */
161 struct inode *data_inode;
162
163 struct btrfs_block_rsv *block_rsv;
164
165 struct backref_cache backref_cache;
166
167 struct file_extent_cluster cluster;
168 /* tree blocks have been processed */
169 struct extent_io_tree processed_blocks;
170 /* map start of tree root to corresponding reloc tree */
171 struct mapping_tree reloc_root_tree;
172 /* list of reloc trees */
173 struct list_head reloc_roots;
174 /* size of metadata reservation for merging reloc trees */
175 u64 merging_rsv_size;
176 /* size of relocated tree nodes */
177 u64 nodes_relocated;
178
179 u64 search_start;
180 u64 extents_found;
181
182 unsigned int stage:8;
183 unsigned int create_reloc_tree:1;
184 unsigned int merge_reloc_tree:1;
185 unsigned int found_file_extent:1;
186 unsigned int commit_transaction:1;
187 };
188
189 /* stages of data relocation */
190 #define MOVE_DATA_EXTENTS 0
191 #define UPDATE_DATA_PTRS 1
192
193 static void remove_backref_node(struct backref_cache *cache,
194 struct backref_node *node);
195 static void __mark_block_processed(struct reloc_control *rc,
196 struct backref_node *node);
197
198 static void mapping_tree_init(struct mapping_tree *tree)
199 {
200 tree->rb_root = RB_ROOT;
201 spin_lock_init(&tree->lock);
202 }
203
204 static void backref_cache_init(struct backref_cache *cache)
205 {
206 int i;
207 cache->rb_root = RB_ROOT;
208 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
209 INIT_LIST_HEAD(&cache->pending[i]);
210 INIT_LIST_HEAD(&cache->changed);
211 INIT_LIST_HEAD(&cache->detached);
212 INIT_LIST_HEAD(&cache->leaves);
213 }
214
215 static void backref_cache_cleanup(struct backref_cache *cache)
216 {
217 struct backref_node *node;
218 int i;
219
220 while (!list_empty(&cache->detached)) {
221 node = list_entry(cache->detached.next,
222 struct backref_node, list);
223 remove_backref_node(cache, node);
224 }
225
226 while (!list_empty(&cache->leaves)) {
227 node = list_entry(cache->leaves.next,
228 struct backref_node, lower);
229 remove_backref_node(cache, node);
230 }
231
232 cache->last_trans = 0;
233
234 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
235 BUG_ON(!list_empty(&cache->pending[i]));
236 BUG_ON(!list_empty(&cache->changed));
237 BUG_ON(!list_empty(&cache->detached));
238 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
239 BUG_ON(cache->nr_nodes);
240 BUG_ON(cache->nr_edges);
241 }
242
243 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
244 {
245 struct backref_node *node;
246
247 node = kzalloc(sizeof(*node), GFP_NOFS);
248 if (node) {
249 INIT_LIST_HEAD(&node->list);
250 INIT_LIST_HEAD(&node->upper);
251 INIT_LIST_HEAD(&node->lower);
252 RB_CLEAR_NODE(&node->rb_node);
253 cache->nr_nodes++;
254 }
255 return node;
256 }
257
258 static void free_backref_node(struct backref_cache *cache,
259 struct backref_node *node)
260 {
261 if (node) {
262 cache->nr_nodes--;
263 kfree(node);
264 }
265 }
266
267 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
268 {
269 struct backref_edge *edge;
270
271 edge = kzalloc(sizeof(*edge), GFP_NOFS);
272 if (edge)
273 cache->nr_edges++;
274 return edge;
275 }
276
277 static void free_backref_edge(struct backref_cache *cache,
278 struct backref_edge *edge)
279 {
280 if (edge) {
281 cache->nr_edges--;
282 kfree(edge);
283 }
284 }
285
286 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
287 struct rb_node *node)
288 {
289 struct rb_node **p = &root->rb_node;
290 struct rb_node *parent = NULL;
291 struct tree_entry *entry;
292
293 while (*p) {
294 parent = *p;
295 entry = rb_entry(parent, struct tree_entry, rb_node);
296
297 if (bytenr < entry->bytenr)
298 p = &(*p)->rb_left;
299 else if (bytenr > entry->bytenr)
300 p = &(*p)->rb_right;
301 else
302 return parent;
303 }
304
305 rb_link_node(node, parent, p);
306 rb_insert_color(node, root);
307 return NULL;
308 }
309
310 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
311 {
312 struct rb_node *n = root->rb_node;
313 struct tree_entry *entry;
314
315 while (n) {
316 entry = rb_entry(n, struct tree_entry, rb_node);
317
318 if (bytenr < entry->bytenr)
319 n = n->rb_left;
320 else if (bytenr > entry->bytenr)
321 n = n->rb_right;
322 else
323 return n;
324 }
325 return NULL;
326 }
327
328 /*
329 * walk up backref nodes until reach node presents tree root
330 */
331 static struct backref_node *walk_up_backref(struct backref_node *node,
332 struct backref_edge *edges[],
333 int *index)
334 {
335 struct backref_edge *edge;
336 int idx = *index;
337
338 while (!list_empty(&node->upper)) {
339 edge = list_entry(node->upper.next,
340 struct backref_edge, list[LOWER]);
341 edges[idx++] = edge;
342 node = edge->node[UPPER];
343 }
344 BUG_ON(node->detached);
345 *index = idx;
346 return node;
347 }
348
349 /*
350 * walk down backref nodes to find start of next reference path
351 */
352 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
353 int *index)
354 {
355 struct backref_edge *edge;
356 struct backref_node *lower;
357 int idx = *index;
358
359 while (idx > 0) {
360 edge = edges[idx - 1];
361 lower = edge->node[LOWER];
362 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
363 idx--;
364 continue;
365 }
366 edge = list_entry(edge->list[LOWER].next,
367 struct backref_edge, list[LOWER]);
368 edges[idx - 1] = edge;
369 *index = idx;
370 return edge->node[UPPER];
371 }
372 *index = 0;
373 return NULL;
374 }
375
376 static void unlock_node_buffer(struct backref_node *node)
377 {
378 if (node->locked) {
379 btrfs_tree_unlock(node->eb);
380 node->locked = 0;
381 }
382 }
383
384 static void drop_node_buffer(struct backref_node *node)
385 {
386 if (node->eb) {
387 unlock_node_buffer(node);
388 free_extent_buffer(node->eb);
389 node->eb = NULL;
390 }
391 }
392
393 static void drop_backref_node(struct backref_cache *tree,
394 struct backref_node *node)
395 {
396 BUG_ON(!list_empty(&node->upper));
397
398 drop_node_buffer(node);
399 list_del(&node->list);
400 list_del(&node->lower);
401 if (!RB_EMPTY_NODE(&node->rb_node))
402 rb_erase(&node->rb_node, &tree->rb_root);
403 free_backref_node(tree, node);
404 }
405
406 /*
407 * remove a backref node from the backref cache
408 */
409 static void remove_backref_node(struct backref_cache *cache,
410 struct backref_node *node)
411 {
412 struct backref_node *upper;
413 struct backref_edge *edge;
414
415 if (!node)
416 return;
417
418 BUG_ON(!node->lowest && !node->detached);
419 while (!list_empty(&node->upper)) {
420 edge = list_entry(node->upper.next, struct backref_edge,
421 list[LOWER]);
422 upper = edge->node[UPPER];
423 list_del(&edge->list[LOWER]);
424 list_del(&edge->list[UPPER]);
425 free_backref_edge(cache, edge);
426
427 if (RB_EMPTY_NODE(&upper->rb_node)) {
428 BUG_ON(!list_empty(&node->upper));
429 drop_backref_node(cache, node);
430 node = upper;
431 node->lowest = 1;
432 continue;
433 }
434 /*
435 * add the node to leaf node list if no other
436 * child block cached.
437 */
438 if (list_empty(&upper->lower)) {
439 list_add_tail(&upper->lower, &cache->leaves);
440 upper->lowest = 1;
441 }
442 }
443
444 drop_backref_node(cache, node);
445 }
446
447 static void update_backref_node(struct backref_cache *cache,
448 struct backref_node *node, u64 bytenr)
449 {
450 struct rb_node *rb_node;
451 rb_erase(&node->rb_node, &cache->rb_root);
452 node->bytenr = bytenr;
453 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
454 BUG_ON(rb_node);
455 }
456
457 /*
458 * update backref cache after a transaction commit
459 */
460 static int update_backref_cache(struct btrfs_trans_handle *trans,
461 struct backref_cache *cache)
462 {
463 struct backref_node *node;
464 int level = 0;
465
466 if (cache->last_trans == 0) {
467 cache->last_trans = trans->transid;
468 return 0;
469 }
470
471 if (cache->last_trans == trans->transid)
472 return 0;
473
474 /*
475 * detached nodes are used to avoid unnecessary backref
476 * lookup. transaction commit changes the extent tree.
477 * so the detached nodes are no longer useful.
478 */
479 while (!list_empty(&cache->detached)) {
480 node = list_entry(cache->detached.next,
481 struct backref_node, list);
482 remove_backref_node(cache, node);
483 }
484
485 while (!list_empty(&cache->changed)) {
486 node = list_entry(cache->changed.next,
487 struct backref_node, list);
488 list_del_init(&node->list);
489 BUG_ON(node->pending);
490 update_backref_node(cache, node, node->new_bytenr);
491 }
492
493 /*
494 * some nodes can be left in the pending list if there were
495 * errors during processing the pending nodes.
496 */
497 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
498 list_for_each_entry(node, &cache->pending[level], list) {
499 BUG_ON(!node->pending);
500 if (node->bytenr == node->new_bytenr)
501 continue;
502 update_backref_node(cache, node, node->new_bytenr);
503 }
504 }
505
506 cache->last_trans = 0;
507 return 1;
508 }
509
510 static int should_ignore_root(struct btrfs_root *root)
511 {
512 struct btrfs_root *reloc_root;
513
514 if (!root->ref_cows)
515 return 0;
516
517 reloc_root = root->reloc_root;
518 if (!reloc_root)
519 return 0;
520
521 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
522 root->fs_info->running_transaction->transid - 1)
523 return 0;
524 /*
525 * if there is reloc tree and it was created in previous
526 * transaction backref lookup can find the reloc tree,
527 * so backref node for the fs tree root is useless for
528 * relocation.
529 */
530 return 1;
531 }
532
533 /*
534 * find reloc tree by address of tree root
535 */
536 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
537 u64 bytenr)
538 {
539 struct rb_node *rb_node;
540 struct mapping_node *node;
541 struct btrfs_root *root = NULL;
542
543 spin_lock(&rc->reloc_root_tree.lock);
544 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
545 if (rb_node) {
546 node = rb_entry(rb_node, struct mapping_node, rb_node);
547 root = (struct btrfs_root *)node->data;
548 }
549 spin_unlock(&rc->reloc_root_tree.lock);
550 return root;
551 }
552
553 static int is_cowonly_root(u64 root_objectid)
554 {
555 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
556 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
557 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
558 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
559 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
560 root_objectid == BTRFS_CSUM_TREE_OBJECTID)
561 return 1;
562 return 0;
563 }
564
565 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
566 u64 root_objectid)
567 {
568 struct btrfs_key key;
569
570 key.objectid = root_objectid;
571 key.type = BTRFS_ROOT_ITEM_KEY;
572 if (is_cowonly_root(root_objectid))
573 key.offset = 0;
574 else
575 key.offset = (u64)-1;
576
577 return btrfs_read_fs_root_no_name(fs_info, &key);
578 }
579
580 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
581 static noinline_for_stack
582 struct btrfs_root *find_tree_root(struct reloc_control *rc,
583 struct extent_buffer *leaf,
584 struct btrfs_extent_ref_v0 *ref0)
585 {
586 struct btrfs_root *root;
587 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
588 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
589
590 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
591
592 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
593 BUG_ON(IS_ERR(root));
594
595 if (root->ref_cows &&
596 generation != btrfs_root_generation(&root->root_item))
597 return NULL;
598
599 return root;
600 }
601 #endif
602
603 static noinline_for_stack
604 int find_inline_backref(struct extent_buffer *leaf, int slot,
605 unsigned long *ptr, unsigned long *end)
606 {
607 struct btrfs_extent_item *ei;
608 struct btrfs_tree_block_info *bi;
609 u32 item_size;
610
611 item_size = btrfs_item_size_nr(leaf, slot);
612 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
613 if (item_size < sizeof(*ei)) {
614 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
615 return 1;
616 }
617 #endif
618 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
619 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
620 BTRFS_EXTENT_FLAG_TREE_BLOCK));
621
622 if (item_size <= sizeof(*ei) + sizeof(*bi)) {
623 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
624 return 1;
625 }
626
627 bi = (struct btrfs_tree_block_info *)(ei + 1);
628 *ptr = (unsigned long)(bi + 1);
629 *end = (unsigned long)ei + item_size;
630 return 0;
631 }
632
633 /*
634 * build backref tree for a given tree block. root of the backref tree
635 * corresponds the tree block, leaves of the backref tree correspond
636 * roots of b-trees that reference the tree block.
637 *
638 * the basic idea of this function is check backrefs of a given block
639 * to find upper level blocks that refernece the block, and then check
640 * bakcrefs of these upper level blocks recursively. the recursion stop
641 * when tree root is reached or backrefs for the block is cached.
642 *
643 * NOTE: if we find backrefs for a block are cached, we know backrefs
644 * for all upper level blocks that directly/indirectly reference the
645 * block are also cached.
646 */
647 static noinline_for_stack
648 struct backref_node *build_backref_tree(struct reloc_control *rc,
649 struct btrfs_key *node_key,
650 int level, u64 bytenr)
651 {
652 struct backref_cache *cache = &rc->backref_cache;
653 struct btrfs_path *path1;
654 struct btrfs_path *path2;
655 struct extent_buffer *eb;
656 struct btrfs_root *root;
657 struct backref_node *cur;
658 struct backref_node *upper;
659 struct backref_node *lower;
660 struct backref_node *node = NULL;
661 struct backref_node *exist = NULL;
662 struct backref_edge *edge;
663 struct rb_node *rb_node;
664 struct btrfs_key key;
665 unsigned long end;
666 unsigned long ptr;
667 LIST_HEAD(list);
668 LIST_HEAD(useless);
669 int cowonly;
670 int ret;
671 int err = 0;
672
673 path1 = btrfs_alloc_path();
674 path2 = btrfs_alloc_path();
675 if (!path1 || !path2) {
676 err = -ENOMEM;
677 goto out;
678 }
679
680 node = alloc_backref_node(cache);
681 if (!node) {
682 err = -ENOMEM;
683 goto out;
684 }
685
686 node->bytenr = bytenr;
687 node->level = level;
688 node->lowest = 1;
689 cur = node;
690 again:
691 end = 0;
692 ptr = 0;
693 key.objectid = cur->bytenr;
694 key.type = BTRFS_EXTENT_ITEM_KEY;
695 key.offset = (u64)-1;
696
697 path1->search_commit_root = 1;
698 path1->skip_locking = 1;
699 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
700 0, 0);
701 if (ret < 0) {
702 err = ret;
703 goto out;
704 }
705 BUG_ON(!ret || !path1->slots[0]);
706
707 path1->slots[0]--;
708
709 WARN_ON(cur->checked);
710 if (!list_empty(&cur->upper)) {
711 /*
712 * the backref was added previously when processsing
713 * backref of type BTRFS_TREE_BLOCK_REF_KEY
714 */
715 BUG_ON(!list_is_singular(&cur->upper));
716 edge = list_entry(cur->upper.next, struct backref_edge,
717 list[LOWER]);
718 BUG_ON(!list_empty(&edge->list[UPPER]));
719 exist = edge->node[UPPER];
720 /*
721 * add the upper level block to pending list if we need
722 * check its backrefs
723 */
724 if (!exist->checked)
725 list_add_tail(&edge->list[UPPER], &list);
726 } else {
727 exist = NULL;
728 }
729
730 while (1) {
731 cond_resched();
732 eb = path1->nodes[0];
733
734 if (ptr >= end) {
735 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
736 ret = btrfs_next_leaf(rc->extent_root, path1);
737 if (ret < 0) {
738 err = ret;
739 goto out;
740 }
741 if (ret > 0)
742 break;
743 eb = path1->nodes[0];
744 }
745
746 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
747 if (key.objectid != cur->bytenr) {
748 WARN_ON(exist);
749 break;
750 }
751
752 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
753 ret = find_inline_backref(eb, path1->slots[0],
754 &ptr, &end);
755 if (ret)
756 goto next;
757 }
758 }
759
760 if (ptr < end) {
761 /* update key for inline back ref */
762 struct btrfs_extent_inline_ref *iref;
763 iref = (struct btrfs_extent_inline_ref *)ptr;
764 key.type = btrfs_extent_inline_ref_type(eb, iref);
765 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
766 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
767 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
768 }
769
770 if (exist &&
771 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
772 exist->owner == key.offset) ||
773 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
774 exist->bytenr == key.offset))) {
775 exist = NULL;
776 goto next;
777 }
778
779 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
780 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
781 key.type == BTRFS_EXTENT_REF_V0_KEY) {
782 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
783 struct btrfs_extent_ref_v0 *ref0;
784 ref0 = btrfs_item_ptr(eb, path1->slots[0],
785 struct btrfs_extent_ref_v0);
786 if (key.objectid == key.offset) {
787 root = find_tree_root(rc, eb, ref0);
788 if (root && !should_ignore_root(root))
789 cur->root = root;
790 else
791 list_add(&cur->list, &useless);
792 break;
793 }
794 if (is_cowonly_root(btrfs_ref_root_v0(eb,
795 ref0)))
796 cur->cowonly = 1;
797 }
798 #else
799 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
800 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
801 #endif
802 if (key.objectid == key.offset) {
803 /*
804 * only root blocks of reloc trees use
805 * backref of this type.
806 */
807 root = find_reloc_root(rc, cur->bytenr);
808 BUG_ON(!root);
809 cur->root = root;
810 break;
811 }
812
813 edge = alloc_backref_edge(cache);
814 if (!edge) {
815 err = -ENOMEM;
816 goto out;
817 }
818 rb_node = tree_search(&cache->rb_root, key.offset);
819 if (!rb_node) {
820 upper = alloc_backref_node(cache);
821 if (!upper) {
822 free_backref_edge(cache, edge);
823 err = -ENOMEM;
824 goto out;
825 }
826 upper->bytenr = key.offset;
827 upper->level = cur->level + 1;
828 /*
829 * backrefs for the upper level block isn't
830 * cached, add the block to pending list
831 */
832 list_add_tail(&edge->list[UPPER], &list);
833 } else {
834 upper = rb_entry(rb_node, struct backref_node,
835 rb_node);
836 BUG_ON(!upper->checked);
837 INIT_LIST_HEAD(&edge->list[UPPER]);
838 }
839 list_add_tail(&edge->list[LOWER], &cur->upper);
840 edge->node[LOWER] = cur;
841 edge->node[UPPER] = upper;
842
843 goto next;
844 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
845 goto next;
846 }
847
848 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
849 root = read_fs_root(rc->extent_root->fs_info, key.offset);
850 if (IS_ERR(root)) {
851 err = PTR_ERR(root);
852 goto out;
853 }
854
855 if (!root->ref_cows)
856 cur->cowonly = 1;
857
858 if (btrfs_root_level(&root->root_item) == cur->level) {
859 /* tree root */
860 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
861 cur->bytenr);
862 if (should_ignore_root(root))
863 list_add(&cur->list, &useless);
864 else
865 cur->root = root;
866 break;
867 }
868
869 level = cur->level + 1;
870
871 /*
872 * searching the tree to find upper level blocks
873 * reference the block.
874 */
875 path2->search_commit_root = 1;
876 path2->skip_locking = 1;
877 path2->lowest_level = level;
878 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
879 path2->lowest_level = 0;
880 if (ret < 0) {
881 err = ret;
882 goto out;
883 }
884 if (ret > 0 && path2->slots[level] > 0)
885 path2->slots[level]--;
886
887 eb = path2->nodes[level];
888 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
889 cur->bytenr);
890
891 lower = cur;
892 for (; level < BTRFS_MAX_LEVEL; level++) {
893 if (!path2->nodes[level]) {
894 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
895 lower->bytenr);
896 if (should_ignore_root(root))
897 list_add(&lower->list, &useless);
898 else
899 lower->root = root;
900 break;
901 }
902
903 edge = alloc_backref_edge(cache);
904 if (!edge) {
905 err = -ENOMEM;
906 goto out;
907 }
908
909 eb = path2->nodes[level];
910 rb_node = tree_search(&cache->rb_root, eb->start);
911 if (!rb_node) {
912 upper = alloc_backref_node(cache);
913 if (!upper) {
914 free_backref_edge(cache, edge);
915 err = -ENOMEM;
916 goto out;
917 }
918 upper->bytenr = eb->start;
919 upper->owner = btrfs_header_owner(eb);
920 upper->level = lower->level + 1;
921 if (!root->ref_cows)
922 upper->cowonly = 1;
923
924 /*
925 * if we know the block isn't shared
926 * we can void checking its backrefs.
927 */
928 if (btrfs_block_can_be_shared(root, eb))
929 upper->checked = 0;
930 else
931 upper->checked = 1;
932
933 /*
934 * add the block to pending list if we
935 * need check its backrefs. only block
936 * at 'cur->level + 1' is added to the
937 * tail of pending list. this guarantees
938 * we check backrefs from lower level
939 * blocks to upper level blocks.
940 */
941 if (!upper->checked &&
942 level == cur->level + 1) {
943 list_add_tail(&edge->list[UPPER],
944 &list);
945 } else
946 INIT_LIST_HEAD(&edge->list[UPPER]);
947 } else {
948 upper = rb_entry(rb_node, struct backref_node,
949 rb_node);
950 BUG_ON(!upper->checked);
951 INIT_LIST_HEAD(&edge->list[UPPER]);
952 if (!upper->owner)
953 upper->owner = btrfs_header_owner(eb);
954 }
955 list_add_tail(&edge->list[LOWER], &lower->upper);
956 edge->node[LOWER] = lower;
957 edge->node[UPPER] = upper;
958
959 if (rb_node)
960 break;
961 lower = upper;
962 upper = NULL;
963 }
964 btrfs_release_path(root, path2);
965 next:
966 if (ptr < end) {
967 ptr += btrfs_extent_inline_ref_size(key.type);
968 if (ptr >= end) {
969 WARN_ON(ptr > end);
970 ptr = 0;
971 end = 0;
972 }
973 }
974 if (ptr >= end)
975 path1->slots[0]++;
976 }
977 btrfs_release_path(rc->extent_root, path1);
978
979 cur->checked = 1;
980 WARN_ON(exist);
981
982 /* the pending list isn't empty, take the first block to process */
983 if (!list_empty(&list)) {
984 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
985 list_del_init(&edge->list[UPPER]);
986 cur = edge->node[UPPER];
987 goto again;
988 }
989
990 /*
991 * everything goes well, connect backref nodes and insert backref nodes
992 * into the cache.
993 */
994 BUG_ON(!node->checked);
995 cowonly = node->cowonly;
996 if (!cowonly) {
997 rb_node = tree_insert(&cache->rb_root, node->bytenr,
998 &node->rb_node);
999 BUG_ON(rb_node);
1000 list_add_tail(&node->lower, &cache->leaves);
1001 }
1002
1003 list_for_each_entry(edge, &node->upper, list[LOWER])
1004 list_add_tail(&edge->list[UPPER], &list);
1005
1006 while (!list_empty(&list)) {
1007 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1008 list_del_init(&edge->list[UPPER]);
1009 upper = edge->node[UPPER];
1010 if (upper->detached) {
1011 list_del(&edge->list[LOWER]);
1012 lower = edge->node[LOWER];
1013 free_backref_edge(cache, edge);
1014 if (list_empty(&lower->upper))
1015 list_add(&lower->list, &useless);
1016 continue;
1017 }
1018
1019 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1020 if (upper->lowest) {
1021 list_del_init(&upper->lower);
1022 upper->lowest = 0;
1023 }
1024
1025 list_add_tail(&edge->list[UPPER], &upper->lower);
1026 continue;
1027 }
1028
1029 BUG_ON(!upper->checked);
1030 BUG_ON(cowonly != upper->cowonly);
1031 if (!cowonly) {
1032 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1033 &upper->rb_node);
1034 BUG_ON(rb_node);
1035 }
1036
1037 list_add_tail(&edge->list[UPPER], &upper->lower);
1038
1039 list_for_each_entry(edge, &upper->upper, list[LOWER])
1040 list_add_tail(&edge->list[UPPER], &list);
1041 }
1042 /*
1043 * process useless backref nodes. backref nodes for tree leaves
1044 * are deleted from the cache. backref nodes for upper level
1045 * tree blocks are left in the cache to avoid unnecessary backref
1046 * lookup.
1047 */
1048 while (!list_empty(&useless)) {
1049 upper = list_entry(useless.next, struct backref_node, list);
1050 list_del_init(&upper->list);
1051 BUG_ON(!list_empty(&upper->upper));
1052 if (upper == node)
1053 node = NULL;
1054 if (upper->lowest) {
1055 list_del_init(&upper->lower);
1056 upper->lowest = 0;
1057 }
1058 while (!list_empty(&upper->lower)) {
1059 edge = list_entry(upper->lower.next,
1060 struct backref_edge, list[UPPER]);
1061 list_del(&edge->list[UPPER]);
1062 list_del(&edge->list[LOWER]);
1063 lower = edge->node[LOWER];
1064 free_backref_edge(cache, edge);
1065
1066 if (list_empty(&lower->upper))
1067 list_add(&lower->list, &useless);
1068 }
1069 __mark_block_processed(rc, upper);
1070 if (upper->level > 0) {
1071 list_add(&upper->list, &cache->detached);
1072 upper->detached = 1;
1073 } else {
1074 rb_erase(&upper->rb_node, &cache->rb_root);
1075 free_backref_node(cache, upper);
1076 }
1077 }
1078 out:
1079 btrfs_free_path(path1);
1080 btrfs_free_path(path2);
1081 if (err) {
1082 while (!list_empty(&useless)) {
1083 lower = list_entry(useless.next,
1084 struct backref_node, upper);
1085 list_del_init(&lower->upper);
1086 }
1087 upper = node;
1088 INIT_LIST_HEAD(&list);
1089 while (upper) {
1090 if (RB_EMPTY_NODE(&upper->rb_node)) {
1091 list_splice_tail(&upper->upper, &list);
1092 free_backref_node(cache, upper);
1093 }
1094
1095 if (list_empty(&list))
1096 break;
1097
1098 edge = list_entry(list.next, struct backref_edge,
1099 list[LOWER]);
1100 list_del(&edge->list[LOWER]);
1101 upper = edge->node[UPPER];
1102 free_backref_edge(cache, edge);
1103 }
1104 return ERR_PTR(err);
1105 }
1106 BUG_ON(node && node->detached);
1107 return node;
1108 }
1109
1110 /*
1111 * helper to add backref node for the newly created snapshot.
1112 * the backref node is created by cloning backref node that
1113 * corresponds to root of source tree
1114 */
1115 static int clone_backref_node(struct btrfs_trans_handle *trans,
1116 struct reloc_control *rc,
1117 struct btrfs_root *src,
1118 struct btrfs_root *dest)
1119 {
1120 struct btrfs_root *reloc_root = src->reloc_root;
1121 struct backref_cache *cache = &rc->backref_cache;
1122 struct backref_node *node = NULL;
1123 struct backref_node *new_node;
1124 struct backref_edge *edge;
1125 struct backref_edge *new_edge;
1126 struct rb_node *rb_node;
1127
1128 if (cache->last_trans > 0)
1129 update_backref_cache(trans, cache);
1130
1131 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1132 if (rb_node) {
1133 node = rb_entry(rb_node, struct backref_node, rb_node);
1134 if (node->detached)
1135 node = NULL;
1136 else
1137 BUG_ON(node->new_bytenr != reloc_root->node->start);
1138 }
1139
1140 if (!node) {
1141 rb_node = tree_search(&cache->rb_root,
1142 reloc_root->commit_root->start);
1143 if (rb_node) {
1144 node = rb_entry(rb_node, struct backref_node,
1145 rb_node);
1146 BUG_ON(node->detached);
1147 }
1148 }
1149
1150 if (!node)
1151 return 0;
1152
1153 new_node = alloc_backref_node(cache);
1154 if (!new_node)
1155 return -ENOMEM;
1156
1157 new_node->bytenr = dest->node->start;
1158 new_node->level = node->level;
1159 new_node->lowest = node->lowest;
1160 new_node->checked = 1;
1161 new_node->root = dest;
1162
1163 if (!node->lowest) {
1164 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1165 new_edge = alloc_backref_edge(cache);
1166 if (!new_edge)
1167 goto fail;
1168
1169 new_edge->node[UPPER] = new_node;
1170 new_edge->node[LOWER] = edge->node[LOWER];
1171 list_add_tail(&new_edge->list[UPPER],
1172 &new_node->lower);
1173 }
1174 }
1175
1176 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1177 &new_node->rb_node);
1178 BUG_ON(rb_node);
1179
1180 if (!new_node->lowest) {
1181 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1182 list_add_tail(&new_edge->list[LOWER],
1183 &new_edge->node[LOWER]->upper);
1184 }
1185 }
1186 return 0;
1187 fail:
1188 while (!list_empty(&new_node->lower)) {
1189 new_edge = list_entry(new_node->lower.next,
1190 struct backref_edge, list[UPPER]);
1191 list_del(&new_edge->list[UPPER]);
1192 free_backref_edge(cache, new_edge);
1193 }
1194 free_backref_node(cache, new_node);
1195 return -ENOMEM;
1196 }
1197
1198 /*
1199 * helper to add 'address of tree root -> reloc tree' mapping
1200 */
1201 static int __add_reloc_root(struct btrfs_root *root)
1202 {
1203 struct rb_node *rb_node;
1204 struct mapping_node *node;
1205 struct reloc_control *rc = root->fs_info->reloc_ctl;
1206
1207 node = kmalloc(sizeof(*node), GFP_NOFS);
1208 BUG_ON(!node);
1209
1210 node->bytenr = root->node->start;
1211 node->data = root;
1212
1213 spin_lock(&rc->reloc_root_tree.lock);
1214 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1215 node->bytenr, &node->rb_node);
1216 spin_unlock(&rc->reloc_root_tree.lock);
1217 BUG_ON(rb_node);
1218
1219 list_add_tail(&root->root_list, &rc->reloc_roots);
1220 return 0;
1221 }
1222
1223 /*
1224 * helper to update/delete the 'address of tree root -> reloc tree'
1225 * mapping
1226 */
1227 static int __update_reloc_root(struct btrfs_root *root, int del)
1228 {
1229 struct rb_node *rb_node;
1230 struct mapping_node *node = NULL;
1231 struct reloc_control *rc = root->fs_info->reloc_ctl;
1232
1233 spin_lock(&rc->reloc_root_tree.lock);
1234 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1235 root->commit_root->start);
1236 if (rb_node) {
1237 node = rb_entry(rb_node, struct mapping_node, rb_node);
1238 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1239 }
1240 spin_unlock(&rc->reloc_root_tree.lock);
1241
1242 BUG_ON((struct btrfs_root *)node->data != root);
1243
1244 if (!del) {
1245 spin_lock(&rc->reloc_root_tree.lock);
1246 node->bytenr = root->node->start;
1247 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1248 node->bytenr, &node->rb_node);
1249 spin_unlock(&rc->reloc_root_tree.lock);
1250 BUG_ON(rb_node);
1251 } else {
1252 list_del_init(&root->root_list);
1253 kfree(node);
1254 }
1255 return 0;
1256 }
1257
1258 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1259 struct btrfs_root *root, u64 objectid)
1260 {
1261 struct btrfs_root *reloc_root;
1262 struct extent_buffer *eb;
1263 struct btrfs_root_item *root_item;
1264 struct btrfs_key root_key;
1265 int ret;
1266
1267 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1268 BUG_ON(!root_item);
1269
1270 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1271 root_key.type = BTRFS_ROOT_ITEM_KEY;
1272 root_key.offset = objectid;
1273
1274 if (root->root_key.objectid == objectid) {
1275 /* called by btrfs_init_reloc_root */
1276 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1277 BTRFS_TREE_RELOC_OBJECTID);
1278 BUG_ON(ret);
1279
1280 btrfs_set_root_last_snapshot(&root->root_item,
1281 trans->transid - 1);
1282 } else {
1283 /*
1284 * called by btrfs_reloc_post_snapshot_hook.
1285 * the source tree is a reloc tree, all tree blocks
1286 * modified after it was created have RELOC flag
1287 * set in their headers. so it's OK to not update
1288 * the 'last_snapshot'.
1289 */
1290 ret = btrfs_copy_root(trans, root, root->node, &eb,
1291 BTRFS_TREE_RELOC_OBJECTID);
1292 BUG_ON(ret);
1293 }
1294
1295 memcpy(root_item, &root->root_item, sizeof(*root_item));
1296 btrfs_set_root_bytenr(root_item, eb->start);
1297 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1298 btrfs_set_root_generation(root_item, trans->transid);
1299
1300 if (root->root_key.objectid == objectid) {
1301 btrfs_set_root_refs(root_item, 0);
1302 memset(&root_item->drop_progress, 0,
1303 sizeof(struct btrfs_disk_key));
1304 root_item->drop_level = 0;
1305 }
1306
1307 btrfs_tree_unlock(eb);
1308 free_extent_buffer(eb);
1309
1310 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1311 &root_key, root_item);
1312 BUG_ON(ret);
1313 kfree(root_item);
1314
1315 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
1316 &root_key);
1317 BUG_ON(IS_ERR(reloc_root));
1318 reloc_root->last_trans = trans->transid;
1319 return reloc_root;
1320 }
1321
1322 /*
1323 * create reloc tree for a given fs tree. reloc tree is just a
1324 * snapshot of the fs tree with special root objectid.
1325 */
1326 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1327 struct btrfs_root *root)
1328 {
1329 struct btrfs_root *reloc_root;
1330 struct reloc_control *rc = root->fs_info->reloc_ctl;
1331 int clear_rsv = 0;
1332
1333 if (root->reloc_root) {
1334 reloc_root = root->reloc_root;
1335 reloc_root->last_trans = trans->transid;
1336 return 0;
1337 }
1338
1339 if (!rc || !rc->create_reloc_tree ||
1340 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1341 return 0;
1342
1343 if (!trans->block_rsv) {
1344 trans->block_rsv = rc->block_rsv;
1345 clear_rsv = 1;
1346 }
1347 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1348 if (clear_rsv)
1349 trans->block_rsv = NULL;
1350
1351 __add_reloc_root(reloc_root);
1352 root->reloc_root = reloc_root;
1353 return 0;
1354 }
1355
1356 /*
1357 * update root item of reloc tree
1358 */
1359 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1360 struct btrfs_root *root)
1361 {
1362 struct btrfs_root *reloc_root;
1363 struct btrfs_root_item *root_item;
1364 int del = 0;
1365 int ret;
1366
1367 if (!root->reloc_root)
1368 return 0;
1369
1370 reloc_root = root->reloc_root;
1371 root_item = &reloc_root->root_item;
1372
1373 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1374 btrfs_root_refs(root_item) == 0) {
1375 root->reloc_root = NULL;
1376 del = 1;
1377 }
1378
1379 __update_reloc_root(reloc_root, del);
1380
1381 if (reloc_root->commit_root != reloc_root->node) {
1382 btrfs_set_root_node(root_item, reloc_root->node);
1383 free_extent_buffer(reloc_root->commit_root);
1384 reloc_root->commit_root = btrfs_root_node(reloc_root);
1385 }
1386
1387 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1388 &reloc_root->root_key, root_item);
1389 BUG_ON(ret);
1390 return 0;
1391 }
1392
1393 /*
1394 * helper to find first cached inode with inode number >= objectid
1395 * in a subvolume
1396 */
1397 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1398 {
1399 struct rb_node *node;
1400 struct rb_node *prev;
1401 struct btrfs_inode *entry;
1402 struct inode *inode;
1403
1404 spin_lock(&root->inode_lock);
1405 again:
1406 node = root->inode_tree.rb_node;
1407 prev = NULL;
1408 while (node) {
1409 prev = node;
1410 entry = rb_entry(node, struct btrfs_inode, rb_node);
1411
1412 if (objectid < entry->vfs_inode.i_ino)
1413 node = node->rb_left;
1414 else if (objectid > entry->vfs_inode.i_ino)
1415 node = node->rb_right;
1416 else
1417 break;
1418 }
1419 if (!node) {
1420 while (prev) {
1421 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1422 if (objectid <= entry->vfs_inode.i_ino) {
1423 node = prev;
1424 break;
1425 }
1426 prev = rb_next(prev);
1427 }
1428 }
1429 while (node) {
1430 entry = rb_entry(node, struct btrfs_inode, rb_node);
1431 inode = igrab(&entry->vfs_inode);
1432 if (inode) {
1433 spin_unlock(&root->inode_lock);
1434 return inode;
1435 }
1436
1437 objectid = entry->vfs_inode.i_ino + 1;
1438 if (cond_resched_lock(&root->inode_lock))
1439 goto again;
1440
1441 node = rb_next(node);
1442 }
1443 spin_unlock(&root->inode_lock);
1444 return NULL;
1445 }
1446
1447 static int in_block_group(u64 bytenr,
1448 struct btrfs_block_group_cache *block_group)
1449 {
1450 if (bytenr >= block_group->key.objectid &&
1451 bytenr < block_group->key.objectid + block_group->key.offset)
1452 return 1;
1453 return 0;
1454 }
1455
1456 /*
1457 * get new location of data
1458 */
1459 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1460 u64 bytenr, u64 num_bytes)
1461 {
1462 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1463 struct btrfs_path *path;
1464 struct btrfs_file_extent_item *fi;
1465 struct extent_buffer *leaf;
1466 int ret;
1467
1468 path = btrfs_alloc_path();
1469 if (!path)
1470 return -ENOMEM;
1471
1472 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1473 ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
1474 bytenr, 0);
1475 if (ret < 0)
1476 goto out;
1477 if (ret > 0) {
1478 ret = -ENOENT;
1479 goto out;
1480 }
1481
1482 leaf = path->nodes[0];
1483 fi = btrfs_item_ptr(leaf, path->slots[0],
1484 struct btrfs_file_extent_item);
1485
1486 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1487 btrfs_file_extent_compression(leaf, fi) ||
1488 btrfs_file_extent_encryption(leaf, fi) ||
1489 btrfs_file_extent_other_encoding(leaf, fi));
1490
1491 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1492 ret = 1;
1493 goto out;
1494 }
1495
1496 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1497 ret = 0;
1498 out:
1499 btrfs_free_path(path);
1500 return ret;
1501 }
1502
1503 /*
1504 * update file extent items in the tree leaf to point to
1505 * the new locations.
1506 */
1507 static noinline_for_stack
1508 int replace_file_extents(struct btrfs_trans_handle *trans,
1509 struct reloc_control *rc,
1510 struct btrfs_root *root,
1511 struct extent_buffer *leaf)
1512 {
1513 struct btrfs_key key;
1514 struct btrfs_file_extent_item *fi;
1515 struct inode *inode = NULL;
1516 u64 parent;
1517 u64 bytenr;
1518 u64 new_bytenr = 0;
1519 u64 num_bytes;
1520 u64 end;
1521 u32 nritems;
1522 u32 i;
1523 int ret;
1524 int first = 1;
1525 int dirty = 0;
1526
1527 if (rc->stage != UPDATE_DATA_PTRS)
1528 return 0;
1529
1530 /* reloc trees always use full backref */
1531 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1532 parent = leaf->start;
1533 else
1534 parent = 0;
1535
1536 nritems = btrfs_header_nritems(leaf);
1537 for (i = 0; i < nritems; i++) {
1538 cond_resched();
1539 btrfs_item_key_to_cpu(leaf, &key, i);
1540 if (key.type != BTRFS_EXTENT_DATA_KEY)
1541 continue;
1542 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1543 if (btrfs_file_extent_type(leaf, fi) ==
1544 BTRFS_FILE_EXTENT_INLINE)
1545 continue;
1546 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1547 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1548 if (bytenr == 0)
1549 continue;
1550 if (!in_block_group(bytenr, rc->block_group))
1551 continue;
1552
1553 /*
1554 * if we are modifying block in fs tree, wait for readpage
1555 * to complete and drop the extent cache
1556 */
1557 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1558 if (first) {
1559 inode = find_next_inode(root, key.objectid);
1560 first = 0;
1561 } else if (inode && inode->i_ino < key.objectid) {
1562 btrfs_add_delayed_iput(inode);
1563 inode = find_next_inode(root, key.objectid);
1564 }
1565 if (inode && inode->i_ino == key.objectid) {
1566 end = key.offset +
1567 btrfs_file_extent_num_bytes(leaf, fi);
1568 WARN_ON(!IS_ALIGNED(key.offset,
1569 root->sectorsize));
1570 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1571 end--;
1572 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1573 key.offset, end,
1574 GFP_NOFS);
1575 if (!ret)
1576 continue;
1577
1578 btrfs_drop_extent_cache(inode, key.offset, end,
1579 1);
1580 unlock_extent(&BTRFS_I(inode)->io_tree,
1581 key.offset, end, GFP_NOFS);
1582 }
1583 }
1584
1585 ret = get_new_location(rc->data_inode, &new_bytenr,
1586 bytenr, num_bytes);
1587 if (ret > 0) {
1588 WARN_ON(1);
1589 continue;
1590 }
1591 BUG_ON(ret < 0);
1592
1593 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1594 dirty = 1;
1595
1596 key.offset -= btrfs_file_extent_offset(leaf, fi);
1597 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1598 num_bytes, parent,
1599 btrfs_header_owner(leaf),
1600 key.objectid, key.offset);
1601 BUG_ON(ret);
1602
1603 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1604 parent, btrfs_header_owner(leaf),
1605 key.objectid, key.offset);
1606 BUG_ON(ret);
1607 }
1608 if (dirty)
1609 btrfs_mark_buffer_dirty(leaf);
1610 if (inode)
1611 btrfs_add_delayed_iput(inode);
1612 return 0;
1613 }
1614
1615 static noinline_for_stack
1616 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1617 struct btrfs_path *path, int level)
1618 {
1619 struct btrfs_disk_key key1;
1620 struct btrfs_disk_key key2;
1621 btrfs_node_key(eb, &key1, slot);
1622 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1623 return memcmp(&key1, &key2, sizeof(key1));
1624 }
1625
1626 /*
1627 * try to replace tree blocks in fs tree with the new blocks
1628 * in reloc tree. tree blocks haven't been modified since the
1629 * reloc tree was create can be replaced.
1630 *
1631 * if a block was replaced, level of the block + 1 is returned.
1632 * if no block got replaced, 0 is returned. if there are other
1633 * errors, a negative error number is returned.
1634 */
1635 static noinline_for_stack
1636 int replace_path(struct btrfs_trans_handle *trans,
1637 struct btrfs_root *dest, struct btrfs_root *src,
1638 struct btrfs_path *path, struct btrfs_key *next_key,
1639 int lowest_level, int max_level)
1640 {
1641 struct extent_buffer *eb;
1642 struct extent_buffer *parent;
1643 struct btrfs_key key;
1644 u64 old_bytenr;
1645 u64 new_bytenr;
1646 u64 old_ptr_gen;
1647 u64 new_ptr_gen;
1648 u64 last_snapshot;
1649 u32 blocksize;
1650 int cow = 0;
1651 int level;
1652 int ret;
1653 int slot;
1654
1655 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1656 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1657
1658 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1659 again:
1660 slot = path->slots[lowest_level];
1661 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1662
1663 eb = btrfs_lock_root_node(dest);
1664 btrfs_set_lock_blocking(eb);
1665 level = btrfs_header_level(eb);
1666
1667 if (level < lowest_level) {
1668 btrfs_tree_unlock(eb);
1669 free_extent_buffer(eb);
1670 return 0;
1671 }
1672
1673 if (cow) {
1674 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1675 BUG_ON(ret);
1676 }
1677 btrfs_set_lock_blocking(eb);
1678
1679 if (next_key) {
1680 next_key->objectid = (u64)-1;
1681 next_key->type = (u8)-1;
1682 next_key->offset = (u64)-1;
1683 }
1684
1685 parent = eb;
1686 while (1) {
1687 level = btrfs_header_level(parent);
1688 BUG_ON(level < lowest_level);
1689
1690 ret = btrfs_bin_search(parent, &key, level, &slot);
1691 if (ret && slot > 0)
1692 slot--;
1693
1694 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1695 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1696
1697 old_bytenr = btrfs_node_blockptr(parent, slot);
1698 blocksize = btrfs_level_size(dest, level - 1);
1699 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1700
1701 if (level <= max_level) {
1702 eb = path->nodes[level];
1703 new_bytenr = btrfs_node_blockptr(eb,
1704 path->slots[level]);
1705 new_ptr_gen = btrfs_node_ptr_generation(eb,
1706 path->slots[level]);
1707 } else {
1708 new_bytenr = 0;
1709 new_ptr_gen = 0;
1710 }
1711
1712 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1713 WARN_ON(1);
1714 ret = level;
1715 break;
1716 }
1717
1718 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1719 memcmp_node_keys(parent, slot, path, level)) {
1720 if (level <= lowest_level) {
1721 ret = 0;
1722 break;
1723 }
1724
1725 eb = read_tree_block(dest, old_bytenr, blocksize,
1726 old_ptr_gen);
1727 BUG_ON(!eb);
1728 btrfs_tree_lock(eb);
1729 if (cow) {
1730 ret = btrfs_cow_block(trans, dest, eb, parent,
1731 slot, &eb);
1732 BUG_ON(ret);
1733 }
1734 btrfs_set_lock_blocking(eb);
1735
1736 btrfs_tree_unlock(parent);
1737 free_extent_buffer(parent);
1738
1739 parent = eb;
1740 continue;
1741 }
1742
1743 if (!cow) {
1744 btrfs_tree_unlock(parent);
1745 free_extent_buffer(parent);
1746 cow = 1;
1747 goto again;
1748 }
1749
1750 btrfs_node_key_to_cpu(path->nodes[level], &key,
1751 path->slots[level]);
1752 btrfs_release_path(src, path);
1753
1754 path->lowest_level = level;
1755 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1756 path->lowest_level = 0;
1757 BUG_ON(ret);
1758
1759 /*
1760 * swap blocks in fs tree and reloc tree.
1761 */
1762 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1763 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1764 btrfs_mark_buffer_dirty(parent);
1765
1766 btrfs_set_node_blockptr(path->nodes[level],
1767 path->slots[level], old_bytenr);
1768 btrfs_set_node_ptr_generation(path->nodes[level],
1769 path->slots[level], old_ptr_gen);
1770 btrfs_mark_buffer_dirty(path->nodes[level]);
1771
1772 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1773 path->nodes[level]->start,
1774 src->root_key.objectid, level - 1, 0);
1775 BUG_ON(ret);
1776 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1777 0, dest->root_key.objectid, level - 1,
1778 0);
1779 BUG_ON(ret);
1780
1781 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1782 path->nodes[level]->start,
1783 src->root_key.objectid, level - 1, 0);
1784 BUG_ON(ret);
1785
1786 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1787 0, dest->root_key.objectid, level - 1,
1788 0);
1789 BUG_ON(ret);
1790
1791 btrfs_unlock_up_safe(path, 0);
1792
1793 ret = level;
1794 break;
1795 }
1796 btrfs_tree_unlock(parent);
1797 free_extent_buffer(parent);
1798 return ret;
1799 }
1800
1801 /*
1802 * helper to find next relocated block in reloc tree
1803 */
1804 static noinline_for_stack
1805 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1806 int *level)
1807 {
1808 struct extent_buffer *eb;
1809 int i;
1810 u64 last_snapshot;
1811 u32 nritems;
1812
1813 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1814
1815 for (i = 0; i < *level; i++) {
1816 free_extent_buffer(path->nodes[i]);
1817 path->nodes[i] = NULL;
1818 }
1819
1820 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1821 eb = path->nodes[i];
1822 nritems = btrfs_header_nritems(eb);
1823 while (path->slots[i] + 1 < nritems) {
1824 path->slots[i]++;
1825 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1826 last_snapshot)
1827 continue;
1828
1829 *level = i;
1830 return 0;
1831 }
1832 free_extent_buffer(path->nodes[i]);
1833 path->nodes[i] = NULL;
1834 }
1835 return 1;
1836 }
1837
1838 /*
1839 * walk down reloc tree to find relocated block of lowest level
1840 */
1841 static noinline_for_stack
1842 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1843 int *level)
1844 {
1845 struct extent_buffer *eb = NULL;
1846 int i;
1847 u64 bytenr;
1848 u64 ptr_gen = 0;
1849 u64 last_snapshot;
1850 u32 blocksize;
1851 u32 nritems;
1852
1853 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1854
1855 for (i = *level; i > 0; i--) {
1856 eb = path->nodes[i];
1857 nritems = btrfs_header_nritems(eb);
1858 while (path->slots[i] < nritems) {
1859 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1860 if (ptr_gen > last_snapshot)
1861 break;
1862 path->slots[i]++;
1863 }
1864 if (path->slots[i] >= nritems) {
1865 if (i == *level)
1866 break;
1867 *level = i + 1;
1868 return 0;
1869 }
1870 if (i == 1) {
1871 *level = i;
1872 return 0;
1873 }
1874
1875 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1876 blocksize = btrfs_level_size(root, i - 1);
1877 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1878 BUG_ON(btrfs_header_level(eb) != i - 1);
1879 path->nodes[i - 1] = eb;
1880 path->slots[i - 1] = 0;
1881 }
1882 return 1;
1883 }
1884
1885 /*
1886 * invalidate extent cache for file extents whose key in range of
1887 * [min_key, max_key)
1888 */
1889 static int invalidate_extent_cache(struct btrfs_root *root,
1890 struct btrfs_key *min_key,
1891 struct btrfs_key *max_key)
1892 {
1893 struct inode *inode = NULL;
1894 u64 objectid;
1895 u64 start, end;
1896
1897 objectid = min_key->objectid;
1898 while (1) {
1899 cond_resched();
1900 iput(inode);
1901
1902 if (objectid > max_key->objectid)
1903 break;
1904
1905 inode = find_next_inode(root, objectid);
1906 if (!inode)
1907 break;
1908
1909 if (inode->i_ino > max_key->objectid) {
1910 iput(inode);
1911 break;
1912 }
1913
1914 objectid = inode->i_ino + 1;
1915 if (!S_ISREG(inode->i_mode))
1916 continue;
1917
1918 if (unlikely(min_key->objectid == inode->i_ino)) {
1919 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1920 continue;
1921 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1922 start = 0;
1923 else {
1924 start = min_key->offset;
1925 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1926 }
1927 } else {
1928 start = 0;
1929 }
1930
1931 if (unlikely(max_key->objectid == inode->i_ino)) {
1932 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1933 continue;
1934 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1935 end = (u64)-1;
1936 } else {
1937 if (max_key->offset == 0)
1938 continue;
1939 end = max_key->offset;
1940 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1941 end--;
1942 }
1943 } else {
1944 end = (u64)-1;
1945 }
1946
1947 /* the lock_extent waits for readpage to complete */
1948 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1949 btrfs_drop_extent_cache(inode, start, end, 1);
1950 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1951 }
1952 return 0;
1953 }
1954
1955 static int find_next_key(struct btrfs_path *path, int level,
1956 struct btrfs_key *key)
1957
1958 {
1959 while (level < BTRFS_MAX_LEVEL) {
1960 if (!path->nodes[level])
1961 break;
1962 if (path->slots[level] + 1 <
1963 btrfs_header_nritems(path->nodes[level])) {
1964 btrfs_node_key_to_cpu(path->nodes[level], key,
1965 path->slots[level] + 1);
1966 return 0;
1967 }
1968 level++;
1969 }
1970 return 1;
1971 }
1972
1973 /*
1974 * merge the relocated tree blocks in reloc tree with corresponding
1975 * fs tree.
1976 */
1977 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1978 struct btrfs_root *root)
1979 {
1980 LIST_HEAD(inode_list);
1981 struct btrfs_key key;
1982 struct btrfs_key next_key;
1983 struct btrfs_trans_handle *trans;
1984 struct btrfs_root *reloc_root;
1985 struct btrfs_root_item *root_item;
1986 struct btrfs_path *path;
1987 struct extent_buffer *leaf;
1988 unsigned long nr;
1989 int level;
1990 int max_level;
1991 int replaced = 0;
1992 int ret;
1993 int err = 0;
1994 u32 min_reserved;
1995
1996 path = btrfs_alloc_path();
1997 if (!path)
1998 return -ENOMEM;
1999
2000 reloc_root = root->reloc_root;
2001 root_item = &reloc_root->root_item;
2002
2003 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2004 level = btrfs_root_level(root_item);
2005 extent_buffer_get(reloc_root->node);
2006 path->nodes[level] = reloc_root->node;
2007 path->slots[level] = 0;
2008 } else {
2009 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2010
2011 level = root_item->drop_level;
2012 BUG_ON(level == 0);
2013 path->lowest_level = level;
2014 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2015 path->lowest_level = 0;
2016 if (ret < 0) {
2017 btrfs_free_path(path);
2018 return ret;
2019 }
2020
2021 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2022 path->slots[level]);
2023 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2024
2025 btrfs_unlock_up_safe(path, 0);
2026 }
2027
2028 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2029 memset(&next_key, 0, sizeof(next_key));
2030
2031 while (1) {
2032 trans = btrfs_start_transaction(root, 0);
2033 BUG_ON(IS_ERR(trans));
2034 trans->block_rsv = rc->block_rsv;
2035
2036 ret = btrfs_block_rsv_check(trans, root, rc->block_rsv,
2037 min_reserved, 0);
2038 if (ret) {
2039 BUG_ON(ret != -EAGAIN);
2040 ret = btrfs_commit_transaction(trans, root);
2041 BUG_ON(ret);
2042 continue;
2043 }
2044
2045 replaced = 0;
2046 max_level = level;
2047
2048 ret = walk_down_reloc_tree(reloc_root, path, &level);
2049 if (ret < 0) {
2050 err = ret;
2051 goto out;
2052 }
2053 if (ret > 0)
2054 break;
2055
2056 if (!find_next_key(path, level, &key) &&
2057 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2058 ret = 0;
2059 } else {
2060 ret = replace_path(trans, root, reloc_root, path,
2061 &next_key, level, max_level);
2062 }
2063 if (ret < 0) {
2064 err = ret;
2065 goto out;
2066 }
2067
2068 if (ret > 0) {
2069 level = ret;
2070 btrfs_node_key_to_cpu(path->nodes[level], &key,
2071 path->slots[level]);
2072 replaced = 1;
2073 }
2074
2075 ret = walk_up_reloc_tree(reloc_root, path, &level);
2076 if (ret > 0)
2077 break;
2078
2079 BUG_ON(level == 0);
2080 /*
2081 * save the merging progress in the drop_progress.
2082 * this is OK since root refs == 1 in this case.
2083 */
2084 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2085 path->slots[level]);
2086 root_item->drop_level = level;
2087
2088 nr = trans->blocks_used;
2089 btrfs_end_transaction_throttle(trans, root);
2090
2091 btrfs_btree_balance_dirty(root, nr);
2092
2093 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2094 invalidate_extent_cache(root, &key, &next_key);
2095 }
2096
2097 /*
2098 * handle the case only one block in the fs tree need to be
2099 * relocated and the block is tree root.
2100 */
2101 leaf = btrfs_lock_root_node(root);
2102 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2103 btrfs_tree_unlock(leaf);
2104 free_extent_buffer(leaf);
2105 if (ret < 0)
2106 err = ret;
2107 out:
2108 btrfs_free_path(path);
2109
2110 if (err == 0) {
2111 memset(&root_item->drop_progress, 0,
2112 sizeof(root_item->drop_progress));
2113 root_item->drop_level = 0;
2114 btrfs_set_root_refs(root_item, 0);
2115 btrfs_update_reloc_root(trans, root);
2116 }
2117
2118 nr = trans->blocks_used;
2119 btrfs_end_transaction_throttle(trans, root);
2120
2121 btrfs_btree_balance_dirty(root, nr);
2122
2123 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2124 invalidate_extent_cache(root, &key, &next_key);
2125
2126 return err;
2127 }
2128
2129 static noinline_for_stack
2130 int prepare_to_merge(struct reloc_control *rc, int err)
2131 {
2132 struct btrfs_root *root = rc->extent_root;
2133 struct btrfs_root *reloc_root;
2134 struct btrfs_trans_handle *trans;
2135 LIST_HEAD(reloc_roots);
2136 u64 num_bytes = 0;
2137 int ret;
2138
2139 mutex_lock(&root->fs_info->trans_mutex);
2140 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2141 rc->merging_rsv_size += rc->nodes_relocated * 2;
2142 mutex_unlock(&root->fs_info->trans_mutex);
2143 again:
2144 if (!err) {
2145 num_bytes = rc->merging_rsv_size;
2146 ret = btrfs_block_rsv_add(NULL, root, rc->block_rsv,
2147 num_bytes);
2148 if (ret)
2149 err = ret;
2150 }
2151
2152 trans = btrfs_join_transaction(rc->extent_root, 1);
2153 if (IS_ERR(trans)) {
2154 if (!err)
2155 btrfs_block_rsv_release(rc->extent_root,
2156 rc->block_rsv, num_bytes);
2157 return PTR_ERR(trans);
2158 }
2159
2160 if (!err) {
2161 if (num_bytes != rc->merging_rsv_size) {
2162 btrfs_end_transaction(trans, rc->extent_root);
2163 btrfs_block_rsv_release(rc->extent_root,
2164 rc->block_rsv, num_bytes);
2165 goto again;
2166 }
2167 }
2168
2169 rc->merge_reloc_tree = 1;
2170
2171 while (!list_empty(&rc->reloc_roots)) {
2172 reloc_root = list_entry(rc->reloc_roots.next,
2173 struct btrfs_root, root_list);
2174 list_del_init(&reloc_root->root_list);
2175
2176 root = read_fs_root(reloc_root->fs_info,
2177 reloc_root->root_key.offset);
2178 BUG_ON(IS_ERR(root));
2179 BUG_ON(root->reloc_root != reloc_root);
2180
2181 /*
2182 * set reference count to 1, so btrfs_recover_relocation
2183 * knows it should resumes merging
2184 */
2185 if (!err)
2186 btrfs_set_root_refs(&reloc_root->root_item, 1);
2187 btrfs_update_reloc_root(trans, root);
2188
2189 list_add(&reloc_root->root_list, &reloc_roots);
2190 }
2191
2192 list_splice(&reloc_roots, &rc->reloc_roots);
2193
2194 if (!err)
2195 btrfs_commit_transaction(trans, rc->extent_root);
2196 else
2197 btrfs_end_transaction(trans, rc->extent_root);
2198 return err;
2199 }
2200
2201 static noinline_for_stack
2202 int merge_reloc_roots(struct reloc_control *rc)
2203 {
2204 struct btrfs_root *root;
2205 struct btrfs_root *reloc_root;
2206 LIST_HEAD(reloc_roots);
2207 int found = 0;
2208 int ret;
2209 again:
2210 root = rc->extent_root;
2211 mutex_lock(&root->fs_info->trans_mutex);
2212 list_splice_init(&rc->reloc_roots, &reloc_roots);
2213 mutex_unlock(&root->fs_info->trans_mutex);
2214
2215 while (!list_empty(&reloc_roots)) {
2216 found = 1;
2217 reloc_root = list_entry(reloc_roots.next,
2218 struct btrfs_root, root_list);
2219
2220 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2221 root = read_fs_root(reloc_root->fs_info,
2222 reloc_root->root_key.offset);
2223 BUG_ON(IS_ERR(root));
2224 BUG_ON(root->reloc_root != reloc_root);
2225
2226 ret = merge_reloc_root(rc, root);
2227 BUG_ON(ret);
2228 } else {
2229 list_del_init(&reloc_root->root_list);
2230 }
2231 btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0);
2232 }
2233
2234 if (found) {
2235 found = 0;
2236 goto again;
2237 }
2238 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2239 return 0;
2240 }
2241
2242 static void free_block_list(struct rb_root *blocks)
2243 {
2244 struct tree_block *block;
2245 struct rb_node *rb_node;
2246 while ((rb_node = rb_first(blocks))) {
2247 block = rb_entry(rb_node, struct tree_block, rb_node);
2248 rb_erase(rb_node, blocks);
2249 kfree(block);
2250 }
2251 }
2252
2253 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2254 struct btrfs_root *reloc_root)
2255 {
2256 struct btrfs_root *root;
2257
2258 if (reloc_root->last_trans == trans->transid)
2259 return 0;
2260
2261 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2262 BUG_ON(IS_ERR(root));
2263 BUG_ON(root->reloc_root != reloc_root);
2264
2265 return btrfs_record_root_in_trans(trans, root);
2266 }
2267
2268 static noinline_for_stack
2269 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2270 struct reloc_control *rc,
2271 struct backref_node *node,
2272 struct backref_edge *edges[], int *nr)
2273 {
2274 struct backref_node *next;
2275 struct btrfs_root *root;
2276 int index = 0;
2277
2278 next = node;
2279 while (1) {
2280 cond_resched();
2281 next = walk_up_backref(next, edges, &index);
2282 root = next->root;
2283 BUG_ON(!root);
2284 BUG_ON(!root->ref_cows);
2285
2286 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2287 record_reloc_root_in_trans(trans, root);
2288 break;
2289 }
2290
2291 btrfs_record_root_in_trans(trans, root);
2292 root = root->reloc_root;
2293
2294 if (next->new_bytenr != root->node->start) {
2295 BUG_ON(next->new_bytenr);
2296 BUG_ON(!list_empty(&next->list));
2297 next->new_bytenr = root->node->start;
2298 next->root = root;
2299 list_add_tail(&next->list,
2300 &rc->backref_cache.changed);
2301 __mark_block_processed(rc, next);
2302 break;
2303 }
2304
2305 WARN_ON(1);
2306 root = NULL;
2307 next = walk_down_backref(edges, &index);
2308 if (!next || next->level <= node->level)
2309 break;
2310 }
2311 if (!root)
2312 return NULL;
2313
2314 *nr = index;
2315 next = node;
2316 /* setup backref node path for btrfs_reloc_cow_block */
2317 while (1) {
2318 rc->backref_cache.path[next->level] = next;
2319 if (--index < 0)
2320 break;
2321 next = edges[index]->node[UPPER];
2322 }
2323 return root;
2324 }
2325
2326 /*
2327 * select a tree root for relocation. return NULL if the block
2328 * is reference counted. we should use do_relocation() in this
2329 * case. return a tree root pointer if the block isn't reference
2330 * counted. return -ENOENT if the block is root of reloc tree.
2331 */
2332 static noinline_for_stack
2333 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2334 struct backref_node *node)
2335 {
2336 struct backref_node *next;
2337 struct btrfs_root *root;
2338 struct btrfs_root *fs_root = NULL;
2339 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2340 int index = 0;
2341
2342 next = node;
2343 while (1) {
2344 cond_resched();
2345 next = walk_up_backref(next, edges, &index);
2346 root = next->root;
2347 BUG_ON(!root);
2348
2349 /* no other choice for non-refernce counted tree */
2350 if (!root->ref_cows)
2351 return root;
2352
2353 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2354 fs_root = root;
2355
2356 if (next != node)
2357 return NULL;
2358
2359 next = walk_down_backref(edges, &index);
2360 if (!next || next->level <= node->level)
2361 break;
2362 }
2363
2364 if (!fs_root)
2365 return ERR_PTR(-ENOENT);
2366 return fs_root;
2367 }
2368
2369 static noinline_for_stack
2370 u64 calcu_metadata_size(struct reloc_control *rc,
2371 struct backref_node *node, int reserve)
2372 {
2373 struct backref_node *next = node;
2374 struct backref_edge *edge;
2375 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2376 u64 num_bytes = 0;
2377 int index = 0;
2378
2379 BUG_ON(reserve && node->processed);
2380
2381 while (next) {
2382 cond_resched();
2383 while (1) {
2384 if (next->processed && (reserve || next != node))
2385 break;
2386
2387 num_bytes += btrfs_level_size(rc->extent_root,
2388 next->level);
2389
2390 if (list_empty(&next->upper))
2391 break;
2392
2393 edge = list_entry(next->upper.next,
2394 struct backref_edge, list[LOWER]);
2395 edges[index++] = edge;
2396 next = edge->node[UPPER];
2397 }
2398 next = walk_down_backref(edges, &index);
2399 }
2400 return num_bytes;
2401 }
2402
2403 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2404 struct reloc_control *rc,
2405 struct backref_node *node)
2406 {
2407 struct btrfs_root *root = rc->extent_root;
2408 u64 num_bytes;
2409 int ret;
2410
2411 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2412
2413 trans->block_rsv = rc->block_rsv;
2414 ret = btrfs_block_rsv_add(trans, root, rc->block_rsv, num_bytes);
2415 if (ret) {
2416 if (ret == -EAGAIN)
2417 rc->commit_transaction = 1;
2418 return ret;
2419 }
2420
2421 return 0;
2422 }
2423
2424 static void release_metadata_space(struct reloc_control *rc,
2425 struct backref_node *node)
2426 {
2427 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2428 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2429 }
2430
2431 /*
2432 * relocate a block tree, and then update pointers in upper level
2433 * blocks that reference the block to point to the new location.
2434 *
2435 * if called by link_to_upper, the block has already been relocated.
2436 * in that case this function just updates pointers.
2437 */
2438 static int do_relocation(struct btrfs_trans_handle *trans,
2439 struct reloc_control *rc,
2440 struct backref_node *node,
2441 struct btrfs_key *key,
2442 struct btrfs_path *path, int lowest)
2443 {
2444 struct backref_node *upper;
2445 struct backref_edge *edge;
2446 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2447 struct btrfs_root *root;
2448 struct extent_buffer *eb;
2449 u32 blocksize;
2450 u64 bytenr;
2451 u64 generation;
2452 int nr;
2453 int slot;
2454 int ret;
2455 int err = 0;
2456
2457 BUG_ON(lowest && node->eb);
2458
2459 path->lowest_level = node->level + 1;
2460 rc->backref_cache.path[node->level] = node;
2461 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2462 cond_resched();
2463
2464 upper = edge->node[UPPER];
2465 root = select_reloc_root(trans, rc, upper, edges, &nr);
2466 BUG_ON(!root);
2467
2468 if (upper->eb && !upper->locked) {
2469 if (!lowest) {
2470 ret = btrfs_bin_search(upper->eb, key,
2471 upper->level, &slot);
2472 BUG_ON(ret);
2473 bytenr = btrfs_node_blockptr(upper->eb, slot);
2474 if (node->eb->start == bytenr)
2475 goto next;
2476 }
2477 drop_node_buffer(upper);
2478 }
2479
2480 if (!upper->eb) {
2481 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2482 if (ret < 0) {
2483 err = ret;
2484 break;
2485 }
2486 BUG_ON(ret > 0);
2487
2488 if (!upper->eb) {
2489 upper->eb = path->nodes[upper->level];
2490 path->nodes[upper->level] = NULL;
2491 } else {
2492 BUG_ON(upper->eb != path->nodes[upper->level]);
2493 }
2494
2495 upper->locked = 1;
2496 path->locks[upper->level] = 0;
2497
2498 slot = path->slots[upper->level];
2499 btrfs_release_path(NULL, path);
2500 } else {
2501 ret = btrfs_bin_search(upper->eb, key, upper->level,
2502 &slot);
2503 BUG_ON(ret);
2504 }
2505
2506 bytenr = btrfs_node_blockptr(upper->eb, slot);
2507 if (lowest) {
2508 BUG_ON(bytenr != node->bytenr);
2509 } else {
2510 if (node->eb->start == bytenr)
2511 goto next;
2512 }
2513
2514 blocksize = btrfs_level_size(root, node->level);
2515 generation = btrfs_node_ptr_generation(upper->eb, slot);
2516 eb = read_tree_block(root, bytenr, blocksize, generation);
2517 if (!eb) {
2518 err = -EIO;
2519 goto next;
2520 }
2521 btrfs_tree_lock(eb);
2522 btrfs_set_lock_blocking(eb);
2523
2524 if (!node->eb) {
2525 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2526 slot, &eb);
2527 btrfs_tree_unlock(eb);
2528 free_extent_buffer(eb);
2529 if (ret < 0) {
2530 err = ret;
2531 goto next;
2532 }
2533 BUG_ON(node->eb != eb);
2534 } else {
2535 btrfs_set_node_blockptr(upper->eb, slot,
2536 node->eb->start);
2537 btrfs_set_node_ptr_generation(upper->eb, slot,
2538 trans->transid);
2539 btrfs_mark_buffer_dirty(upper->eb);
2540
2541 ret = btrfs_inc_extent_ref(trans, root,
2542 node->eb->start, blocksize,
2543 upper->eb->start,
2544 btrfs_header_owner(upper->eb),
2545 node->level, 0);
2546 BUG_ON(ret);
2547
2548 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2549 BUG_ON(ret);
2550 }
2551 next:
2552 if (!upper->pending)
2553 drop_node_buffer(upper);
2554 else
2555 unlock_node_buffer(upper);
2556 if (err)
2557 break;
2558 }
2559
2560 if (!err && node->pending) {
2561 drop_node_buffer(node);
2562 list_move_tail(&node->list, &rc->backref_cache.changed);
2563 node->pending = 0;
2564 }
2565
2566 path->lowest_level = 0;
2567 BUG_ON(err == -ENOSPC);
2568 return err;
2569 }
2570
2571 static int link_to_upper(struct btrfs_trans_handle *trans,
2572 struct reloc_control *rc,
2573 struct backref_node *node,
2574 struct btrfs_path *path)
2575 {
2576 struct btrfs_key key;
2577
2578 btrfs_node_key_to_cpu(node->eb, &key, 0);
2579 return do_relocation(trans, rc, node, &key, path, 0);
2580 }
2581
2582 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2583 struct reloc_control *rc,
2584 struct btrfs_path *path, int err)
2585 {
2586 LIST_HEAD(list);
2587 struct backref_cache *cache = &rc->backref_cache;
2588 struct backref_node *node;
2589 int level;
2590 int ret;
2591
2592 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2593 while (!list_empty(&cache->pending[level])) {
2594 node = list_entry(cache->pending[level].next,
2595 struct backref_node, list);
2596 list_move_tail(&node->list, &list);
2597 BUG_ON(!node->pending);
2598
2599 if (!err) {
2600 ret = link_to_upper(trans, rc, node, path);
2601 if (ret < 0)
2602 err = ret;
2603 }
2604 }
2605 list_splice_init(&list, &cache->pending[level]);
2606 }
2607 return err;
2608 }
2609
2610 static void mark_block_processed(struct reloc_control *rc,
2611 u64 bytenr, u32 blocksize)
2612 {
2613 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2614 EXTENT_DIRTY, GFP_NOFS);
2615 }
2616
2617 static void __mark_block_processed(struct reloc_control *rc,
2618 struct backref_node *node)
2619 {
2620 u32 blocksize;
2621 if (node->level == 0 ||
2622 in_block_group(node->bytenr, rc->block_group)) {
2623 blocksize = btrfs_level_size(rc->extent_root, node->level);
2624 mark_block_processed(rc, node->bytenr, blocksize);
2625 }
2626 node->processed = 1;
2627 }
2628
2629 /*
2630 * mark a block and all blocks directly/indirectly reference the block
2631 * as processed.
2632 */
2633 static void update_processed_blocks(struct reloc_control *rc,
2634 struct backref_node *node)
2635 {
2636 struct backref_node *next = node;
2637 struct backref_edge *edge;
2638 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2639 int index = 0;
2640
2641 while (next) {
2642 cond_resched();
2643 while (1) {
2644 if (next->processed)
2645 break;
2646
2647 __mark_block_processed(rc, next);
2648
2649 if (list_empty(&next->upper))
2650 break;
2651
2652 edge = list_entry(next->upper.next,
2653 struct backref_edge, list[LOWER]);
2654 edges[index++] = edge;
2655 next = edge->node[UPPER];
2656 }
2657 next = walk_down_backref(edges, &index);
2658 }
2659 }
2660
2661 static int tree_block_processed(u64 bytenr, u32 blocksize,
2662 struct reloc_control *rc)
2663 {
2664 if (test_range_bit(&rc->processed_blocks, bytenr,
2665 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2666 return 1;
2667 return 0;
2668 }
2669
2670 static int get_tree_block_key(struct reloc_control *rc,
2671 struct tree_block *block)
2672 {
2673 struct extent_buffer *eb;
2674
2675 BUG_ON(block->key_ready);
2676 eb = read_tree_block(rc->extent_root, block->bytenr,
2677 block->key.objectid, block->key.offset);
2678 BUG_ON(!eb);
2679 WARN_ON(btrfs_header_level(eb) != block->level);
2680 if (block->level == 0)
2681 btrfs_item_key_to_cpu(eb, &block->key, 0);
2682 else
2683 btrfs_node_key_to_cpu(eb, &block->key, 0);
2684 free_extent_buffer(eb);
2685 block->key_ready = 1;
2686 return 0;
2687 }
2688
2689 static int reada_tree_block(struct reloc_control *rc,
2690 struct tree_block *block)
2691 {
2692 BUG_ON(block->key_ready);
2693 readahead_tree_block(rc->extent_root, block->bytenr,
2694 block->key.objectid, block->key.offset);
2695 return 0;
2696 }
2697
2698 /*
2699 * helper function to relocate a tree block
2700 */
2701 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2702 struct reloc_control *rc,
2703 struct backref_node *node,
2704 struct btrfs_key *key,
2705 struct btrfs_path *path)
2706 {
2707 struct btrfs_root *root;
2708 int release = 0;
2709 int ret = 0;
2710
2711 if (!node)
2712 return 0;
2713
2714 BUG_ON(node->processed);
2715 root = select_one_root(trans, node);
2716 if (root == ERR_PTR(-ENOENT)) {
2717 update_processed_blocks(rc, node);
2718 goto out;
2719 }
2720
2721 if (!root || root->ref_cows) {
2722 ret = reserve_metadata_space(trans, rc, node);
2723 if (ret)
2724 goto out;
2725 release = 1;
2726 }
2727
2728 if (root) {
2729 if (root->ref_cows) {
2730 BUG_ON(node->new_bytenr);
2731 BUG_ON(!list_empty(&node->list));
2732 btrfs_record_root_in_trans(trans, root);
2733 root = root->reloc_root;
2734 node->new_bytenr = root->node->start;
2735 node->root = root;
2736 list_add_tail(&node->list, &rc->backref_cache.changed);
2737 } else {
2738 path->lowest_level = node->level;
2739 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2740 btrfs_release_path(root, path);
2741 if (ret > 0)
2742 ret = 0;
2743 }
2744 if (!ret)
2745 update_processed_blocks(rc, node);
2746 } else {
2747 ret = do_relocation(trans, rc, node, key, path, 1);
2748 }
2749 out:
2750 if (ret || node->level == 0 || node->cowonly) {
2751 if (release)
2752 release_metadata_space(rc, node);
2753 remove_backref_node(&rc->backref_cache, node);
2754 }
2755 return ret;
2756 }
2757
2758 /*
2759 * relocate a list of blocks
2760 */
2761 static noinline_for_stack
2762 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2763 struct reloc_control *rc, struct rb_root *blocks)
2764 {
2765 struct backref_node *node;
2766 struct btrfs_path *path;
2767 struct tree_block *block;
2768 struct rb_node *rb_node;
2769 int ret;
2770 int err = 0;
2771
2772 path = btrfs_alloc_path();
2773 if (!path)
2774 return -ENOMEM;
2775
2776 rb_node = rb_first(blocks);
2777 while (rb_node) {
2778 block = rb_entry(rb_node, struct tree_block, rb_node);
2779 if (!block->key_ready)
2780 reada_tree_block(rc, block);
2781 rb_node = rb_next(rb_node);
2782 }
2783
2784 rb_node = rb_first(blocks);
2785 while (rb_node) {
2786 block = rb_entry(rb_node, struct tree_block, rb_node);
2787 if (!block->key_ready)
2788 get_tree_block_key(rc, block);
2789 rb_node = rb_next(rb_node);
2790 }
2791
2792 rb_node = rb_first(blocks);
2793 while (rb_node) {
2794 block = rb_entry(rb_node, struct tree_block, rb_node);
2795
2796 node = build_backref_tree(rc, &block->key,
2797 block->level, block->bytenr);
2798 if (IS_ERR(node)) {
2799 err = PTR_ERR(node);
2800 goto out;
2801 }
2802
2803 ret = relocate_tree_block(trans, rc, node, &block->key,
2804 path);
2805 if (ret < 0) {
2806 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2807 err = ret;
2808 goto out;
2809 }
2810 rb_node = rb_next(rb_node);
2811 }
2812 out:
2813 free_block_list(blocks);
2814 err = finish_pending_nodes(trans, rc, path, err);
2815
2816 btrfs_free_path(path);
2817 return err;
2818 }
2819
2820 static noinline_for_stack
2821 int prealloc_file_extent_cluster(struct inode *inode,
2822 struct file_extent_cluster *cluster)
2823 {
2824 u64 alloc_hint = 0;
2825 u64 start;
2826 u64 end;
2827 u64 offset = BTRFS_I(inode)->index_cnt;
2828 u64 num_bytes;
2829 int nr = 0;
2830 int ret = 0;
2831
2832 BUG_ON(cluster->start != cluster->boundary[0]);
2833 mutex_lock(&inode->i_mutex);
2834
2835 ret = btrfs_check_data_free_space(inode, cluster->end +
2836 1 - cluster->start);
2837 if (ret)
2838 goto out;
2839
2840 while (nr < cluster->nr) {
2841 start = cluster->boundary[nr] - offset;
2842 if (nr + 1 < cluster->nr)
2843 end = cluster->boundary[nr + 1] - 1 - offset;
2844 else
2845 end = cluster->end - offset;
2846
2847 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2848 num_bytes = end + 1 - start;
2849 ret = btrfs_prealloc_file_range(inode, 0, start,
2850 num_bytes, num_bytes,
2851 end + 1, &alloc_hint);
2852 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2853 if (ret)
2854 break;
2855 nr++;
2856 }
2857 btrfs_free_reserved_data_space(inode, cluster->end +
2858 1 - cluster->start);
2859 out:
2860 mutex_unlock(&inode->i_mutex);
2861 return ret;
2862 }
2863
2864 static noinline_for_stack
2865 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
2866 u64 block_start)
2867 {
2868 struct btrfs_root *root = BTRFS_I(inode)->root;
2869 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2870 struct extent_map *em;
2871 int ret = 0;
2872
2873 em = alloc_extent_map(GFP_NOFS);
2874 if (!em)
2875 return -ENOMEM;
2876
2877 em->start = start;
2878 em->len = end + 1 - start;
2879 em->block_len = em->len;
2880 em->block_start = block_start;
2881 em->bdev = root->fs_info->fs_devices->latest_bdev;
2882 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2883
2884 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2885 while (1) {
2886 write_lock(&em_tree->lock);
2887 ret = add_extent_mapping(em_tree, em);
2888 write_unlock(&em_tree->lock);
2889 if (ret != -EEXIST) {
2890 free_extent_map(em);
2891 break;
2892 }
2893 btrfs_drop_extent_cache(inode, start, end, 0);
2894 }
2895 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2896 return ret;
2897 }
2898
2899 static int relocate_file_extent_cluster(struct inode *inode,
2900 struct file_extent_cluster *cluster)
2901 {
2902 u64 page_start;
2903 u64 page_end;
2904 u64 offset = BTRFS_I(inode)->index_cnt;
2905 unsigned long index;
2906 unsigned long last_index;
2907 struct page *page;
2908 struct file_ra_state *ra;
2909 int nr = 0;
2910 int ret = 0;
2911
2912 if (!cluster->nr)
2913 return 0;
2914
2915 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2916 if (!ra)
2917 return -ENOMEM;
2918
2919 ret = prealloc_file_extent_cluster(inode, cluster);
2920 if (ret)
2921 goto out;
2922
2923 file_ra_state_init(ra, inode->i_mapping);
2924
2925 ret = setup_extent_mapping(inode, cluster->start - offset,
2926 cluster->end - offset, cluster->start);
2927 if (ret)
2928 goto out;
2929
2930 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
2931 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
2932 while (index <= last_index) {
2933 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
2934 if (ret)
2935 goto out;
2936
2937 page = find_lock_page(inode->i_mapping, index);
2938 if (!page) {
2939 page_cache_sync_readahead(inode->i_mapping,
2940 ra, NULL, index,
2941 last_index + 1 - index);
2942 page = grab_cache_page(inode->i_mapping, index);
2943 if (!page) {
2944 btrfs_delalloc_release_metadata(inode,
2945 PAGE_CACHE_SIZE);
2946 ret = -ENOMEM;
2947 goto out;
2948 }
2949 }
2950
2951 if (PageReadahead(page)) {
2952 page_cache_async_readahead(inode->i_mapping,
2953 ra, NULL, page, index,
2954 last_index + 1 - index);
2955 }
2956
2957 if (!PageUptodate(page)) {
2958 btrfs_readpage(NULL, page);
2959 lock_page(page);
2960 if (!PageUptodate(page)) {
2961 unlock_page(page);
2962 page_cache_release(page);
2963 btrfs_delalloc_release_metadata(inode,
2964 PAGE_CACHE_SIZE);
2965 ret = -EIO;
2966 goto out;
2967 }
2968 }
2969
2970 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2971 page_end = page_start + PAGE_CACHE_SIZE - 1;
2972
2973 lock_extent(&BTRFS_I(inode)->io_tree,
2974 page_start, page_end, GFP_NOFS);
2975
2976 set_page_extent_mapped(page);
2977
2978 if (nr < cluster->nr &&
2979 page_start + offset == cluster->boundary[nr]) {
2980 set_extent_bits(&BTRFS_I(inode)->io_tree,
2981 page_start, page_end,
2982 EXTENT_BOUNDARY, GFP_NOFS);
2983 nr++;
2984 }
2985
2986 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
2987 set_page_dirty(page);
2988
2989 unlock_extent(&BTRFS_I(inode)->io_tree,
2990 page_start, page_end, GFP_NOFS);
2991 unlock_page(page);
2992 page_cache_release(page);
2993
2994 index++;
2995 balance_dirty_pages_ratelimited(inode->i_mapping);
2996 btrfs_throttle(BTRFS_I(inode)->root);
2997 }
2998 WARN_ON(nr != cluster->nr);
2999 out:
3000 kfree(ra);
3001 return ret;
3002 }
3003
3004 static noinline_for_stack
3005 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3006 struct file_extent_cluster *cluster)
3007 {
3008 int ret;
3009
3010 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3011 ret = relocate_file_extent_cluster(inode, cluster);
3012 if (ret)
3013 return ret;
3014 cluster->nr = 0;
3015 }
3016
3017 if (!cluster->nr)
3018 cluster->start = extent_key->objectid;
3019 else
3020 BUG_ON(cluster->nr >= MAX_EXTENTS);
3021 cluster->end = extent_key->objectid + extent_key->offset - 1;
3022 cluster->boundary[cluster->nr] = extent_key->objectid;
3023 cluster->nr++;
3024
3025 if (cluster->nr >= MAX_EXTENTS) {
3026 ret = relocate_file_extent_cluster(inode, cluster);
3027 if (ret)
3028 return ret;
3029 cluster->nr = 0;
3030 }
3031 return 0;
3032 }
3033
3034 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3035 static int get_ref_objectid_v0(struct reloc_control *rc,
3036 struct btrfs_path *path,
3037 struct btrfs_key *extent_key,
3038 u64 *ref_objectid, int *path_change)
3039 {
3040 struct btrfs_key key;
3041 struct extent_buffer *leaf;
3042 struct btrfs_extent_ref_v0 *ref0;
3043 int ret;
3044 int slot;
3045
3046 leaf = path->nodes[0];
3047 slot = path->slots[0];
3048 while (1) {
3049 if (slot >= btrfs_header_nritems(leaf)) {
3050 ret = btrfs_next_leaf(rc->extent_root, path);
3051 if (ret < 0)
3052 return ret;
3053 BUG_ON(ret > 0);
3054 leaf = path->nodes[0];
3055 slot = path->slots[0];
3056 if (path_change)
3057 *path_change = 1;
3058 }
3059 btrfs_item_key_to_cpu(leaf, &key, slot);
3060 if (key.objectid != extent_key->objectid)
3061 return -ENOENT;
3062
3063 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3064 slot++;
3065 continue;
3066 }
3067 ref0 = btrfs_item_ptr(leaf, slot,
3068 struct btrfs_extent_ref_v0);
3069 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3070 break;
3071 }
3072 return 0;
3073 }
3074 #endif
3075
3076 /*
3077 * helper to add a tree block to the list.
3078 * the major work is getting the generation and level of the block
3079 */
3080 static int add_tree_block(struct reloc_control *rc,
3081 struct btrfs_key *extent_key,
3082 struct btrfs_path *path,
3083 struct rb_root *blocks)
3084 {
3085 struct extent_buffer *eb;
3086 struct btrfs_extent_item *ei;
3087 struct btrfs_tree_block_info *bi;
3088 struct tree_block *block;
3089 struct rb_node *rb_node;
3090 u32 item_size;
3091 int level = -1;
3092 int generation;
3093
3094 eb = path->nodes[0];
3095 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3096
3097 if (item_size >= sizeof(*ei) + sizeof(*bi)) {
3098 ei = btrfs_item_ptr(eb, path->slots[0],
3099 struct btrfs_extent_item);
3100 bi = (struct btrfs_tree_block_info *)(ei + 1);
3101 generation = btrfs_extent_generation(eb, ei);
3102 level = btrfs_tree_block_level(eb, bi);
3103 } else {
3104 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3105 u64 ref_owner;
3106 int ret;
3107
3108 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3109 ret = get_ref_objectid_v0(rc, path, extent_key,
3110 &ref_owner, NULL);
3111 if (ret < 0)
3112 return ret;
3113 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3114 level = (int)ref_owner;
3115 /* FIXME: get real generation */
3116 generation = 0;
3117 #else
3118 BUG();
3119 #endif
3120 }
3121
3122 btrfs_release_path(rc->extent_root, path);
3123
3124 BUG_ON(level == -1);
3125
3126 block = kmalloc(sizeof(*block), GFP_NOFS);
3127 if (!block)
3128 return -ENOMEM;
3129
3130 block->bytenr = extent_key->objectid;
3131 block->key.objectid = extent_key->offset;
3132 block->key.offset = generation;
3133 block->level = level;
3134 block->key_ready = 0;
3135
3136 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3137 BUG_ON(rb_node);
3138
3139 return 0;
3140 }
3141
3142 /*
3143 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3144 */
3145 static int __add_tree_block(struct reloc_control *rc,
3146 u64 bytenr, u32 blocksize,
3147 struct rb_root *blocks)
3148 {
3149 struct btrfs_path *path;
3150 struct btrfs_key key;
3151 int ret;
3152
3153 if (tree_block_processed(bytenr, blocksize, rc))
3154 return 0;
3155
3156 if (tree_search(blocks, bytenr))
3157 return 0;
3158
3159 path = btrfs_alloc_path();
3160 if (!path)
3161 return -ENOMEM;
3162
3163 key.objectid = bytenr;
3164 key.type = BTRFS_EXTENT_ITEM_KEY;
3165 key.offset = blocksize;
3166
3167 path->search_commit_root = 1;
3168 path->skip_locking = 1;
3169 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3170 if (ret < 0)
3171 goto out;
3172 BUG_ON(ret);
3173
3174 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3175 ret = add_tree_block(rc, &key, path, blocks);
3176 out:
3177 btrfs_free_path(path);
3178 return ret;
3179 }
3180
3181 /*
3182 * helper to check if the block use full backrefs for pointers in it
3183 */
3184 static int block_use_full_backref(struct reloc_control *rc,
3185 struct extent_buffer *eb)
3186 {
3187 u64 flags;
3188 int ret;
3189
3190 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3191 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3192 return 1;
3193
3194 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3195 eb->start, eb->len, NULL, &flags);
3196 BUG_ON(ret);
3197
3198 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3199 ret = 1;
3200 else
3201 ret = 0;
3202 return ret;
3203 }
3204
3205 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3206 struct inode *inode, u64 ino)
3207 {
3208 struct btrfs_key key;
3209 struct btrfs_path *path;
3210 struct btrfs_root *root = fs_info->tree_root;
3211 struct btrfs_trans_handle *trans;
3212 unsigned long nr;
3213 int ret = 0;
3214
3215 if (inode)
3216 goto truncate;
3217
3218 key.objectid = ino;
3219 key.type = BTRFS_INODE_ITEM_KEY;
3220 key.offset = 0;
3221
3222 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3223 if (!inode || IS_ERR(inode) || is_bad_inode(inode)) {
3224 if (inode && !IS_ERR(inode))
3225 iput(inode);
3226 return -ENOENT;
3227 }
3228
3229 truncate:
3230 path = btrfs_alloc_path();
3231 if (!path) {
3232 ret = -ENOMEM;
3233 goto out;
3234 }
3235
3236 trans = btrfs_join_transaction(root, 0);
3237 if (IS_ERR(trans)) {
3238 btrfs_free_path(path);
3239 ret = PTR_ERR(trans);
3240 goto out;
3241 }
3242
3243 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
3244
3245 btrfs_free_path(path);
3246 nr = trans->blocks_used;
3247 btrfs_end_transaction(trans, root);
3248 btrfs_btree_balance_dirty(root, nr);
3249 out:
3250 iput(inode);
3251 return ret;
3252 }
3253
3254 /*
3255 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3256 * this function scans fs tree to find blocks reference the data extent
3257 */
3258 static int find_data_references(struct reloc_control *rc,
3259 struct btrfs_key *extent_key,
3260 struct extent_buffer *leaf,
3261 struct btrfs_extent_data_ref *ref,
3262 struct rb_root *blocks)
3263 {
3264 struct btrfs_path *path;
3265 struct tree_block *block;
3266 struct btrfs_root *root;
3267 struct btrfs_file_extent_item *fi;
3268 struct rb_node *rb_node;
3269 struct btrfs_key key;
3270 u64 ref_root;
3271 u64 ref_objectid;
3272 u64 ref_offset;
3273 u32 ref_count;
3274 u32 nritems;
3275 int err = 0;
3276 int added = 0;
3277 int counted;
3278 int ret;
3279
3280 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3281 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3282 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3283 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3284
3285 /*
3286 * This is an extent belonging to the free space cache, lets just delete
3287 * it and redo the search.
3288 */
3289 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3290 ret = delete_block_group_cache(rc->extent_root->fs_info,
3291 NULL, ref_objectid);
3292 if (ret != -ENOENT)
3293 return ret;
3294 ret = 0;
3295 }
3296
3297 path = btrfs_alloc_path();
3298 if (!path)
3299 return -ENOMEM;
3300
3301 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3302 if (IS_ERR(root)) {
3303 err = PTR_ERR(root);
3304 goto out;
3305 }
3306
3307 key.objectid = ref_objectid;
3308 key.offset = ref_offset;
3309 key.type = BTRFS_EXTENT_DATA_KEY;
3310
3311 path->search_commit_root = 1;
3312 path->skip_locking = 1;
3313 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3314 if (ret < 0) {
3315 err = ret;
3316 goto out;
3317 }
3318
3319 leaf = path->nodes[0];
3320 nritems = btrfs_header_nritems(leaf);
3321 /*
3322 * the references in tree blocks that use full backrefs
3323 * are not counted in
3324 */
3325 if (block_use_full_backref(rc, leaf))
3326 counted = 0;
3327 else
3328 counted = 1;
3329 rb_node = tree_search(blocks, leaf->start);
3330 if (rb_node) {
3331 if (counted)
3332 added = 1;
3333 else
3334 path->slots[0] = nritems;
3335 }
3336
3337 while (ref_count > 0) {
3338 while (path->slots[0] >= nritems) {
3339 ret = btrfs_next_leaf(root, path);
3340 if (ret < 0) {
3341 err = ret;
3342 goto out;
3343 }
3344 if (ret > 0) {
3345 WARN_ON(1);
3346 goto out;
3347 }
3348
3349 leaf = path->nodes[0];
3350 nritems = btrfs_header_nritems(leaf);
3351 added = 0;
3352
3353 if (block_use_full_backref(rc, leaf))
3354 counted = 0;
3355 else
3356 counted = 1;
3357 rb_node = tree_search(blocks, leaf->start);
3358 if (rb_node) {
3359 if (counted)
3360 added = 1;
3361 else
3362 path->slots[0] = nritems;
3363 }
3364 }
3365
3366 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3367 if (key.objectid != ref_objectid ||
3368 key.type != BTRFS_EXTENT_DATA_KEY) {
3369 WARN_ON(1);
3370 break;
3371 }
3372
3373 fi = btrfs_item_ptr(leaf, path->slots[0],
3374 struct btrfs_file_extent_item);
3375
3376 if (btrfs_file_extent_type(leaf, fi) ==
3377 BTRFS_FILE_EXTENT_INLINE)
3378 goto next;
3379
3380 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3381 extent_key->objectid)
3382 goto next;
3383
3384 key.offset -= btrfs_file_extent_offset(leaf, fi);
3385 if (key.offset != ref_offset)
3386 goto next;
3387
3388 if (counted)
3389 ref_count--;
3390 if (added)
3391 goto next;
3392
3393 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3394 block = kmalloc(sizeof(*block), GFP_NOFS);
3395 if (!block) {
3396 err = -ENOMEM;
3397 break;
3398 }
3399 block->bytenr = leaf->start;
3400 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3401 block->level = 0;
3402 block->key_ready = 1;
3403 rb_node = tree_insert(blocks, block->bytenr,
3404 &block->rb_node);
3405 BUG_ON(rb_node);
3406 }
3407 if (counted)
3408 added = 1;
3409 else
3410 path->slots[0] = nritems;
3411 next:
3412 path->slots[0]++;
3413
3414 }
3415 out:
3416 btrfs_free_path(path);
3417 return err;
3418 }
3419
3420 /*
3421 * hepler to find all tree blocks that reference a given data extent
3422 */
3423 static noinline_for_stack
3424 int add_data_references(struct reloc_control *rc,
3425 struct btrfs_key *extent_key,
3426 struct btrfs_path *path,
3427 struct rb_root *blocks)
3428 {
3429 struct btrfs_key key;
3430 struct extent_buffer *eb;
3431 struct btrfs_extent_data_ref *dref;
3432 struct btrfs_extent_inline_ref *iref;
3433 unsigned long ptr;
3434 unsigned long end;
3435 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3436 int ret;
3437 int err = 0;
3438
3439 eb = path->nodes[0];
3440 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3441 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3442 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3443 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3444 ptr = end;
3445 else
3446 #endif
3447 ptr += sizeof(struct btrfs_extent_item);
3448
3449 while (ptr < end) {
3450 iref = (struct btrfs_extent_inline_ref *)ptr;
3451 key.type = btrfs_extent_inline_ref_type(eb, iref);
3452 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3453 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3454 ret = __add_tree_block(rc, key.offset, blocksize,
3455 blocks);
3456 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3457 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3458 ret = find_data_references(rc, extent_key,
3459 eb, dref, blocks);
3460 } else {
3461 BUG();
3462 }
3463 ptr += btrfs_extent_inline_ref_size(key.type);
3464 }
3465 WARN_ON(ptr > end);
3466
3467 while (1) {
3468 cond_resched();
3469 eb = path->nodes[0];
3470 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3471 ret = btrfs_next_leaf(rc->extent_root, path);
3472 if (ret < 0) {
3473 err = ret;
3474 break;
3475 }
3476 if (ret > 0)
3477 break;
3478 eb = path->nodes[0];
3479 }
3480
3481 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3482 if (key.objectid != extent_key->objectid)
3483 break;
3484
3485 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3486 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3487 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3488 #else
3489 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3490 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3491 #endif
3492 ret = __add_tree_block(rc, key.offset, blocksize,
3493 blocks);
3494 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3495 dref = btrfs_item_ptr(eb, path->slots[0],
3496 struct btrfs_extent_data_ref);
3497 ret = find_data_references(rc, extent_key,
3498 eb, dref, blocks);
3499 } else {
3500 ret = 0;
3501 }
3502 if (ret) {
3503 err = ret;
3504 break;
3505 }
3506 path->slots[0]++;
3507 }
3508 btrfs_release_path(rc->extent_root, path);
3509 if (err)
3510 free_block_list(blocks);
3511 return err;
3512 }
3513
3514 /*
3515 * hepler to find next unprocessed extent
3516 */
3517 static noinline_for_stack
3518 int find_next_extent(struct btrfs_trans_handle *trans,
3519 struct reloc_control *rc, struct btrfs_path *path,
3520 struct btrfs_key *extent_key)
3521 {
3522 struct btrfs_key key;
3523 struct extent_buffer *leaf;
3524 u64 start, end, last;
3525 int ret;
3526
3527 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3528 while (1) {
3529 cond_resched();
3530 if (rc->search_start >= last) {
3531 ret = 1;
3532 break;
3533 }
3534
3535 key.objectid = rc->search_start;
3536 key.type = BTRFS_EXTENT_ITEM_KEY;
3537 key.offset = 0;
3538
3539 path->search_commit_root = 1;
3540 path->skip_locking = 1;
3541 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3542 0, 0);
3543 if (ret < 0)
3544 break;
3545 next:
3546 leaf = path->nodes[0];
3547 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3548 ret = btrfs_next_leaf(rc->extent_root, path);
3549 if (ret != 0)
3550 break;
3551 leaf = path->nodes[0];
3552 }
3553
3554 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3555 if (key.objectid >= last) {
3556 ret = 1;
3557 break;
3558 }
3559
3560 if (key.type != BTRFS_EXTENT_ITEM_KEY ||
3561 key.objectid + key.offset <= rc->search_start) {
3562 path->slots[0]++;
3563 goto next;
3564 }
3565
3566 ret = find_first_extent_bit(&rc->processed_blocks,
3567 key.objectid, &start, &end,
3568 EXTENT_DIRTY);
3569
3570 if (ret == 0 && start <= key.objectid) {
3571 btrfs_release_path(rc->extent_root, path);
3572 rc->search_start = end + 1;
3573 } else {
3574 rc->search_start = key.objectid + key.offset;
3575 memcpy(extent_key, &key, sizeof(key));
3576 return 0;
3577 }
3578 }
3579 btrfs_release_path(rc->extent_root, path);
3580 return ret;
3581 }
3582
3583 static void set_reloc_control(struct reloc_control *rc)
3584 {
3585 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3586 mutex_lock(&fs_info->trans_mutex);
3587 fs_info->reloc_ctl = rc;
3588 mutex_unlock(&fs_info->trans_mutex);
3589 }
3590
3591 static void unset_reloc_control(struct reloc_control *rc)
3592 {
3593 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3594 mutex_lock(&fs_info->trans_mutex);
3595 fs_info->reloc_ctl = NULL;
3596 mutex_unlock(&fs_info->trans_mutex);
3597 }
3598
3599 static int check_extent_flags(u64 flags)
3600 {
3601 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3602 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3603 return 1;
3604 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3605 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3606 return 1;
3607 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3608 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3609 return 1;
3610 return 0;
3611 }
3612
3613 static noinline_for_stack
3614 int prepare_to_relocate(struct reloc_control *rc)
3615 {
3616 struct btrfs_trans_handle *trans;
3617 int ret;
3618
3619 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root);
3620 if (!rc->block_rsv)
3621 return -ENOMEM;
3622
3623 /*
3624 * reserve some space for creating reloc trees.
3625 * btrfs_init_reloc_root will use them when there
3626 * is no reservation in transaction handle.
3627 */
3628 ret = btrfs_block_rsv_add(NULL, rc->extent_root, rc->block_rsv,
3629 rc->extent_root->nodesize * 256);
3630 if (ret)
3631 return ret;
3632
3633 rc->block_rsv->refill_used = 1;
3634 btrfs_add_durable_block_rsv(rc->extent_root->fs_info, rc->block_rsv);
3635
3636 memset(&rc->cluster, 0, sizeof(rc->cluster));
3637 rc->search_start = rc->block_group->key.objectid;
3638 rc->extents_found = 0;
3639 rc->nodes_relocated = 0;
3640 rc->merging_rsv_size = 0;
3641
3642 rc->create_reloc_tree = 1;
3643 set_reloc_control(rc);
3644
3645 trans = btrfs_join_transaction(rc->extent_root, 1);
3646 BUG_ON(IS_ERR(trans));
3647 btrfs_commit_transaction(trans, rc->extent_root);
3648 return 0;
3649 }
3650
3651 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3652 {
3653 struct rb_root blocks = RB_ROOT;
3654 struct btrfs_key key;
3655 struct btrfs_trans_handle *trans = NULL;
3656 struct btrfs_path *path;
3657 struct btrfs_extent_item *ei;
3658 unsigned long nr;
3659 u64 flags;
3660 u32 item_size;
3661 int ret;
3662 int err = 0;
3663 int progress = 0;
3664
3665 path = btrfs_alloc_path();
3666 if (!path)
3667 return -ENOMEM;
3668
3669 ret = prepare_to_relocate(rc);
3670 if (ret) {
3671 err = ret;
3672 goto out_free;
3673 }
3674
3675 while (1) {
3676 progress++;
3677 trans = btrfs_start_transaction(rc->extent_root, 0);
3678 BUG_ON(IS_ERR(trans));
3679 restart:
3680 if (update_backref_cache(trans, &rc->backref_cache)) {
3681 btrfs_end_transaction(trans, rc->extent_root);
3682 continue;
3683 }
3684
3685 ret = find_next_extent(trans, rc, path, &key);
3686 if (ret < 0)
3687 err = ret;
3688 if (ret != 0)
3689 break;
3690
3691 rc->extents_found++;
3692
3693 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3694 struct btrfs_extent_item);
3695 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3696 if (item_size >= sizeof(*ei)) {
3697 flags = btrfs_extent_flags(path->nodes[0], ei);
3698 ret = check_extent_flags(flags);
3699 BUG_ON(ret);
3700
3701 } else {
3702 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3703 u64 ref_owner;
3704 int path_change = 0;
3705
3706 BUG_ON(item_size !=
3707 sizeof(struct btrfs_extent_item_v0));
3708 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3709 &path_change);
3710 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3711 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3712 else
3713 flags = BTRFS_EXTENT_FLAG_DATA;
3714
3715 if (path_change) {
3716 btrfs_release_path(rc->extent_root, path);
3717
3718 path->search_commit_root = 1;
3719 path->skip_locking = 1;
3720 ret = btrfs_search_slot(NULL, rc->extent_root,
3721 &key, path, 0, 0);
3722 if (ret < 0) {
3723 err = ret;
3724 break;
3725 }
3726 BUG_ON(ret > 0);
3727 }
3728 #else
3729 BUG();
3730 #endif
3731 }
3732
3733 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3734 ret = add_tree_block(rc, &key, path, &blocks);
3735 } else if (rc->stage == UPDATE_DATA_PTRS &&
3736 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3737 ret = add_data_references(rc, &key, path, &blocks);
3738 } else {
3739 btrfs_release_path(rc->extent_root, path);
3740 ret = 0;
3741 }
3742 if (ret < 0) {
3743 err = ret;
3744 break;
3745 }
3746
3747 if (!RB_EMPTY_ROOT(&blocks)) {
3748 ret = relocate_tree_blocks(trans, rc, &blocks);
3749 if (ret < 0) {
3750 if (ret != -EAGAIN) {
3751 err = ret;
3752 break;
3753 }
3754 rc->extents_found--;
3755 rc->search_start = key.objectid;
3756 }
3757 }
3758
3759 ret = btrfs_block_rsv_check(trans, rc->extent_root,
3760 rc->block_rsv, 0, 5);
3761 if (ret < 0) {
3762 if (ret != -EAGAIN) {
3763 err = ret;
3764 WARN_ON(1);
3765 break;
3766 }
3767 rc->commit_transaction = 1;
3768 }
3769
3770 if (rc->commit_transaction) {
3771 rc->commit_transaction = 0;
3772 ret = btrfs_commit_transaction(trans, rc->extent_root);
3773 BUG_ON(ret);
3774 } else {
3775 nr = trans->blocks_used;
3776 btrfs_end_transaction_throttle(trans, rc->extent_root);
3777 btrfs_btree_balance_dirty(rc->extent_root, nr);
3778 }
3779 trans = NULL;
3780
3781 if (rc->stage == MOVE_DATA_EXTENTS &&
3782 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3783 rc->found_file_extent = 1;
3784 ret = relocate_data_extent(rc->data_inode,
3785 &key, &rc->cluster);
3786 if (ret < 0) {
3787 err = ret;
3788 break;
3789 }
3790 }
3791 }
3792 if (trans && progress && err == -ENOSPC) {
3793 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
3794 rc->block_group->flags);
3795 if (ret == 0) {
3796 err = 0;
3797 progress = 0;
3798 goto restart;
3799 }
3800 }
3801
3802 btrfs_release_path(rc->extent_root, path);
3803 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3804 GFP_NOFS);
3805
3806 if (trans) {
3807 nr = trans->blocks_used;
3808 btrfs_end_transaction_throttle(trans, rc->extent_root);
3809 btrfs_btree_balance_dirty(rc->extent_root, nr);
3810 }
3811
3812 if (!err) {
3813 ret = relocate_file_extent_cluster(rc->data_inode,
3814 &rc->cluster);
3815 if (ret < 0)
3816 err = ret;
3817 }
3818
3819 rc->create_reloc_tree = 0;
3820 set_reloc_control(rc);
3821
3822 backref_cache_cleanup(&rc->backref_cache);
3823 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3824
3825 err = prepare_to_merge(rc, err);
3826
3827 merge_reloc_roots(rc);
3828
3829 rc->merge_reloc_tree = 0;
3830 unset_reloc_control(rc);
3831 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3832
3833 /* get rid of pinned extents */
3834 trans = btrfs_join_transaction(rc->extent_root, 1);
3835 if (IS_ERR(trans))
3836 err = PTR_ERR(trans);
3837 else
3838 btrfs_commit_transaction(trans, rc->extent_root);
3839 out_free:
3840 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
3841 btrfs_free_path(path);
3842 return err;
3843 }
3844
3845 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3846 struct btrfs_root *root, u64 objectid)
3847 {
3848 struct btrfs_path *path;
3849 struct btrfs_inode_item *item;
3850 struct extent_buffer *leaf;
3851 int ret;
3852
3853 path = btrfs_alloc_path();
3854 if (!path)
3855 return -ENOMEM;
3856
3857 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3858 if (ret)
3859 goto out;
3860
3861 leaf = path->nodes[0];
3862 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3863 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
3864 btrfs_set_inode_generation(leaf, item, 1);
3865 btrfs_set_inode_size(leaf, item, 0);
3866 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3867 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3868 BTRFS_INODE_PREALLOC);
3869 btrfs_mark_buffer_dirty(leaf);
3870 btrfs_release_path(root, path);
3871 out:
3872 btrfs_free_path(path);
3873 return ret;
3874 }
3875
3876 /*
3877 * helper to create inode for data relocation.
3878 * the inode is in data relocation tree and its link count is 0
3879 */
3880 static noinline_for_stack
3881 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3882 struct btrfs_block_group_cache *group)
3883 {
3884 struct inode *inode = NULL;
3885 struct btrfs_trans_handle *trans;
3886 struct btrfs_root *root;
3887 struct btrfs_key key;
3888 unsigned long nr;
3889 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
3890 int err = 0;
3891
3892 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
3893 if (IS_ERR(root))
3894 return ERR_CAST(root);
3895
3896 trans = btrfs_start_transaction(root, 6);
3897 if (IS_ERR(trans))
3898 return ERR_CAST(trans);
3899
3900 err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
3901 if (err)
3902 goto out;
3903
3904 err = __insert_orphan_inode(trans, root, objectid);
3905 BUG_ON(err);
3906
3907 key.objectid = objectid;
3908 key.type = BTRFS_INODE_ITEM_KEY;
3909 key.offset = 0;
3910 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
3911 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
3912 BTRFS_I(inode)->index_cnt = group->key.objectid;
3913
3914 err = btrfs_orphan_add(trans, inode);
3915 out:
3916 nr = trans->blocks_used;
3917 btrfs_end_transaction(trans, root);
3918 btrfs_btree_balance_dirty(root, nr);
3919 if (err) {
3920 if (inode)
3921 iput(inode);
3922 inode = ERR_PTR(err);
3923 }
3924 return inode;
3925 }
3926
3927 static struct reloc_control *alloc_reloc_control(void)
3928 {
3929 struct reloc_control *rc;
3930
3931 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3932 if (!rc)
3933 return NULL;
3934
3935 INIT_LIST_HEAD(&rc->reloc_roots);
3936 backref_cache_init(&rc->backref_cache);
3937 mapping_tree_init(&rc->reloc_root_tree);
3938 extent_io_tree_init(&rc->processed_blocks, NULL, GFP_NOFS);
3939 return rc;
3940 }
3941
3942 /*
3943 * function to relocate all extents in a block group.
3944 */
3945 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
3946 {
3947 struct btrfs_fs_info *fs_info = extent_root->fs_info;
3948 struct reloc_control *rc;
3949 struct inode *inode;
3950 struct btrfs_path *path;
3951 int ret;
3952 int rw = 0;
3953 int err = 0;
3954
3955 rc = alloc_reloc_control();
3956 if (!rc)
3957 return -ENOMEM;
3958
3959 rc->extent_root = extent_root;
3960
3961 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
3962 BUG_ON(!rc->block_group);
3963
3964 if (!rc->block_group->ro) {
3965 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
3966 if (ret) {
3967 err = ret;
3968 goto out;
3969 }
3970 rw = 1;
3971 }
3972
3973 path = btrfs_alloc_path();
3974 if (!path) {
3975 err = -ENOMEM;
3976 goto out;
3977 }
3978
3979 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
3980 path);
3981 btrfs_free_path(path);
3982
3983 if (!IS_ERR(inode))
3984 ret = delete_block_group_cache(fs_info, inode, 0);
3985 else
3986 ret = PTR_ERR(inode);
3987
3988 if (ret && ret != -ENOENT) {
3989 err = ret;
3990 goto out;
3991 }
3992
3993 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
3994 if (IS_ERR(rc->data_inode)) {
3995 err = PTR_ERR(rc->data_inode);
3996 rc->data_inode = NULL;
3997 goto out;
3998 }
3999
4000 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
4001 (unsigned long long)rc->block_group->key.objectid,
4002 (unsigned long long)rc->block_group->flags);
4003
4004 btrfs_start_delalloc_inodes(fs_info->tree_root, 0);
4005 btrfs_wait_ordered_extents(fs_info->tree_root, 0, 0);
4006
4007 while (1) {
4008 mutex_lock(&fs_info->cleaner_mutex);
4009
4010 btrfs_clean_old_snapshots(fs_info->tree_root);
4011 ret = relocate_block_group(rc);
4012
4013 mutex_unlock(&fs_info->cleaner_mutex);
4014 if (ret < 0) {
4015 err = ret;
4016 goto out;
4017 }
4018
4019 if (rc->extents_found == 0)
4020 break;
4021
4022 printk(KERN_INFO "btrfs: found %llu extents\n",
4023 (unsigned long long)rc->extents_found);
4024
4025 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4026 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
4027 invalidate_mapping_pages(rc->data_inode->i_mapping,
4028 0, -1);
4029 rc->stage = UPDATE_DATA_PTRS;
4030 }
4031 }
4032
4033 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
4034 rc->block_group->key.objectid,
4035 rc->block_group->key.objectid +
4036 rc->block_group->key.offset - 1);
4037
4038 WARN_ON(rc->block_group->pinned > 0);
4039 WARN_ON(rc->block_group->reserved > 0);
4040 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4041 out:
4042 if (err && rw)
4043 btrfs_set_block_group_rw(extent_root, rc->block_group);
4044 iput(rc->data_inode);
4045 btrfs_put_block_group(rc->block_group);
4046 kfree(rc);
4047 return err;
4048 }
4049
4050 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4051 {
4052 struct btrfs_trans_handle *trans;
4053 int ret;
4054
4055 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4056 BUG_ON(IS_ERR(trans));
4057
4058 memset(&root->root_item.drop_progress, 0,
4059 sizeof(root->root_item.drop_progress));
4060 root->root_item.drop_level = 0;
4061 btrfs_set_root_refs(&root->root_item, 0);
4062 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4063 &root->root_key, &root->root_item);
4064 BUG_ON(ret);
4065
4066 ret = btrfs_end_transaction(trans, root->fs_info->tree_root);
4067 BUG_ON(ret);
4068 return 0;
4069 }
4070
4071 /*
4072 * recover relocation interrupted by system crash.
4073 *
4074 * this function resumes merging reloc trees with corresponding fs trees.
4075 * this is important for keeping the sharing of tree blocks
4076 */
4077 int btrfs_recover_relocation(struct btrfs_root *root)
4078 {
4079 LIST_HEAD(reloc_roots);
4080 struct btrfs_key key;
4081 struct btrfs_root *fs_root;
4082 struct btrfs_root *reloc_root;
4083 struct btrfs_path *path;
4084 struct extent_buffer *leaf;
4085 struct reloc_control *rc = NULL;
4086 struct btrfs_trans_handle *trans;
4087 int ret;
4088 int err = 0;
4089
4090 path = btrfs_alloc_path();
4091 if (!path)
4092 return -ENOMEM;
4093
4094 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4095 key.type = BTRFS_ROOT_ITEM_KEY;
4096 key.offset = (u64)-1;
4097
4098 while (1) {
4099 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4100 path, 0, 0);
4101 if (ret < 0) {
4102 err = ret;
4103 goto out;
4104 }
4105 if (ret > 0) {
4106 if (path->slots[0] == 0)
4107 break;
4108 path->slots[0]--;
4109 }
4110 leaf = path->nodes[0];
4111 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4112 btrfs_release_path(root->fs_info->tree_root, path);
4113
4114 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4115 key.type != BTRFS_ROOT_ITEM_KEY)
4116 break;
4117
4118 reloc_root = btrfs_read_fs_root_no_radix(root, &key);
4119 if (IS_ERR(reloc_root)) {
4120 err = PTR_ERR(reloc_root);
4121 goto out;
4122 }
4123
4124 list_add(&reloc_root->root_list, &reloc_roots);
4125
4126 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4127 fs_root = read_fs_root(root->fs_info,
4128 reloc_root->root_key.offset);
4129 if (IS_ERR(fs_root)) {
4130 ret = PTR_ERR(fs_root);
4131 if (ret != -ENOENT) {
4132 err = ret;
4133 goto out;
4134 }
4135 mark_garbage_root(reloc_root);
4136 }
4137 }
4138
4139 if (key.offset == 0)
4140 break;
4141
4142 key.offset--;
4143 }
4144 btrfs_release_path(root->fs_info->tree_root, path);
4145
4146 if (list_empty(&reloc_roots))
4147 goto out;
4148
4149 rc = alloc_reloc_control();
4150 if (!rc) {
4151 err = -ENOMEM;
4152 goto out;
4153 }
4154
4155 rc->extent_root = root->fs_info->extent_root;
4156
4157 set_reloc_control(rc);
4158
4159 trans = btrfs_join_transaction(rc->extent_root, 1);
4160 if (IS_ERR(trans)) {
4161 unset_reloc_control(rc);
4162 err = PTR_ERR(trans);
4163 goto out_free;
4164 }
4165
4166 rc->merge_reloc_tree = 1;
4167
4168 while (!list_empty(&reloc_roots)) {
4169 reloc_root = list_entry(reloc_roots.next,
4170 struct btrfs_root, root_list);
4171 list_del(&reloc_root->root_list);
4172
4173 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4174 list_add_tail(&reloc_root->root_list,
4175 &rc->reloc_roots);
4176 continue;
4177 }
4178
4179 fs_root = read_fs_root(root->fs_info,
4180 reloc_root->root_key.offset);
4181 BUG_ON(IS_ERR(fs_root));
4182
4183 __add_reloc_root(reloc_root);
4184 fs_root->reloc_root = reloc_root;
4185 }
4186
4187 btrfs_commit_transaction(trans, rc->extent_root);
4188
4189 merge_reloc_roots(rc);
4190
4191 unset_reloc_control(rc);
4192
4193 trans = btrfs_join_transaction(rc->extent_root, 1);
4194 if (IS_ERR(trans))
4195 err = PTR_ERR(trans);
4196 else
4197 btrfs_commit_transaction(trans, rc->extent_root);
4198 out_free:
4199 kfree(rc);
4200 out:
4201 while (!list_empty(&reloc_roots)) {
4202 reloc_root = list_entry(reloc_roots.next,
4203 struct btrfs_root, root_list);
4204 list_del(&reloc_root->root_list);
4205 free_extent_buffer(reloc_root->node);
4206 free_extent_buffer(reloc_root->commit_root);
4207 kfree(reloc_root);
4208 }
4209 btrfs_free_path(path);
4210
4211 if (err == 0) {
4212 /* cleanup orphan inode in data relocation tree */
4213 fs_root = read_fs_root(root->fs_info,
4214 BTRFS_DATA_RELOC_TREE_OBJECTID);
4215 if (IS_ERR(fs_root))
4216 err = PTR_ERR(fs_root);
4217 else
4218 err = btrfs_orphan_cleanup(fs_root);
4219 }
4220 return err;
4221 }
4222
4223 /*
4224 * helper to add ordered checksum for data relocation.
4225 *
4226 * cloning checksum properly handles the nodatasum extents.
4227 * it also saves CPU time to re-calculate the checksum.
4228 */
4229 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4230 {
4231 struct btrfs_ordered_sum *sums;
4232 struct btrfs_sector_sum *sector_sum;
4233 struct btrfs_ordered_extent *ordered;
4234 struct btrfs_root *root = BTRFS_I(inode)->root;
4235 size_t offset;
4236 int ret;
4237 u64 disk_bytenr;
4238 LIST_HEAD(list);
4239
4240 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4241 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4242
4243 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4244 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4245 disk_bytenr + len - 1, &list);
4246
4247 while (!list_empty(&list)) {
4248 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4249 list_del_init(&sums->list);
4250
4251 sector_sum = sums->sums;
4252 sums->bytenr = ordered->start;
4253
4254 offset = 0;
4255 while (offset < sums->len) {
4256 sector_sum->bytenr += ordered->start - disk_bytenr;
4257 sector_sum++;
4258 offset += root->sectorsize;
4259 }
4260
4261 btrfs_add_ordered_sum(inode, ordered, sums);
4262 }
4263 btrfs_put_ordered_extent(ordered);
4264 return ret;
4265 }
4266
4267 void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4268 struct btrfs_root *root, struct extent_buffer *buf,
4269 struct extent_buffer *cow)
4270 {
4271 struct reloc_control *rc;
4272 struct backref_node *node;
4273 int first_cow = 0;
4274 int level;
4275 int ret;
4276
4277 rc = root->fs_info->reloc_ctl;
4278 if (!rc)
4279 return;
4280
4281 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4282 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4283
4284 level = btrfs_header_level(buf);
4285 if (btrfs_header_generation(buf) <=
4286 btrfs_root_last_snapshot(&root->root_item))
4287 first_cow = 1;
4288
4289 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4290 rc->create_reloc_tree) {
4291 WARN_ON(!first_cow && level == 0);
4292
4293 node = rc->backref_cache.path[level];
4294 BUG_ON(node->bytenr != buf->start &&
4295 node->new_bytenr != buf->start);
4296
4297 drop_node_buffer(node);
4298 extent_buffer_get(cow);
4299 node->eb = cow;
4300 node->new_bytenr = cow->start;
4301
4302 if (!node->pending) {
4303 list_move_tail(&node->list,
4304 &rc->backref_cache.pending[level]);
4305 node->pending = 1;
4306 }
4307
4308 if (first_cow)
4309 __mark_block_processed(rc, node);
4310
4311 if (first_cow && level > 0)
4312 rc->nodes_relocated += buf->len;
4313 }
4314
4315 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) {
4316 ret = replace_file_extents(trans, rc, root, cow);
4317 BUG_ON(ret);
4318 }
4319 }
4320
4321 /*
4322 * called before creating snapshot. it calculates metadata reservation
4323 * requried for relocating tree blocks in the snapshot
4324 */
4325 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4326 struct btrfs_pending_snapshot *pending,
4327 u64 *bytes_to_reserve)
4328 {
4329 struct btrfs_root *root;
4330 struct reloc_control *rc;
4331
4332 root = pending->root;
4333 if (!root->reloc_root)
4334 return;
4335
4336 rc = root->fs_info->reloc_ctl;
4337 if (!rc->merge_reloc_tree)
4338 return;
4339
4340 root = root->reloc_root;
4341 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4342 /*
4343 * relocation is in the stage of merging trees. the space
4344 * used by merging a reloc tree is twice the size of
4345 * relocated tree nodes in the worst case. half for cowing
4346 * the reloc tree, half for cowing the fs tree. the space
4347 * used by cowing the reloc tree will be freed after the
4348 * tree is dropped. if we create snapshot, cowing the fs
4349 * tree may use more space than it frees. so we need
4350 * reserve extra space.
4351 */
4352 *bytes_to_reserve += rc->nodes_relocated;
4353 }
4354
4355 /*
4356 * called after snapshot is created. migrate block reservation
4357 * and create reloc root for the newly created snapshot
4358 */
4359 void btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4360 struct btrfs_pending_snapshot *pending)
4361 {
4362 struct btrfs_root *root = pending->root;
4363 struct btrfs_root *reloc_root;
4364 struct btrfs_root *new_root;
4365 struct reloc_control *rc;
4366 int ret;
4367
4368 if (!root->reloc_root)
4369 return;
4370
4371 rc = root->fs_info->reloc_ctl;
4372 rc->merging_rsv_size += rc->nodes_relocated;
4373
4374 if (rc->merge_reloc_tree) {
4375 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4376 rc->block_rsv,
4377 rc->nodes_relocated);
4378 BUG_ON(ret);
4379 }
4380
4381 new_root = pending->snap;
4382 reloc_root = create_reloc_root(trans, root->reloc_root,
4383 new_root->root_key.objectid);
4384
4385 __add_reloc_root(reloc_root);
4386 new_root->reloc_root = reloc_root;
4387
4388 if (rc->create_reloc_tree) {
4389 ret = clone_backref_node(trans, rc, root, reloc_root);
4390 BUG_ON(ret);
4391 }
4392 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree