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Btrfs: Always use 64bit inode number
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / btrfs / relocation.c
1 /*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33 #include "inode-map.h"
34
35 /*
36 * backref_node, mapping_node and tree_block start with this
37 */
38 struct tree_entry {
39 struct rb_node rb_node;
40 u64 bytenr;
41 };
42
43 /*
44 * present a tree block in the backref cache
45 */
46 struct backref_node {
47 struct rb_node rb_node;
48 u64 bytenr;
49
50 u64 new_bytenr;
51 /* objectid of tree block owner, can be not uptodate */
52 u64 owner;
53 /* link to pending, changed or detached list */
54 struct list_head list;
55 /* list of upper level blocks reference this block */
56 struct list_head upper;
57 /* list of child blocks in the cache */
58 struct list_head lower;
59 /* NULL if this node is not tree root */
60 struct btrfs_root *root;
61 /* extent buffer got by COW the block */
62 struct extent_buffer *eb;
63 /* level of tree block */
64 unsigned int level:8;
65 /* is the block in non-reference counted tree */
66 unsigned int cowonly:1;
67 /* 1 if no child node in the cache */
68 unsigned int lowest:1;
69 /* is the extent buffer locked */
70 unsigned int locked:1;
71 /* has the block been processed */
72 unsigned int processed:1;
73 /* have backrefs of this block been checked */
74 unsigned int checked:1;
75 /*
76 * 1 if corresponding block has been cowed but some upper
77 * level block pointers may not point to the new location
78 */
79 unsigned int pending:1;
80 /*
81 * 1 if the backref node isn't connected to any other
82 * backref node.
83 */
84 unsigned int detached:1;
85 };
86
87 /*
88 * present a block pointer in the backref cache
89 */
90 struct backref_edge {
91 struct list_head list[2];
92 struct backref_node *node[2];
93 };
94
95 #define LOWER 0
96 #define UPPER 1
97
98 struct backref_cache {
99 /* red black tree of all backref nodes in the cache */
100 struct rb_root rb_root;
101 /* for passing backref nodes to btrfs_reloc_cow_block */
102 struct backref_node *path[BTRFS_MAX_LEVEL];
103 /*
104 * list of blocks that have been cowed but some block
105 * pointers in upper level blocks may not reflect the
106 * new location
107 */
108 struct list_head pending[BTRFS_MAX_LEVEL];
109 /* list of backref nodes with no child node */
110 struct list_head leaves;
111 /* list of blocks that have been cowed in current transaction */
112 struct list_head changed;
113 /* list of detached backref node. */
114 struct list_head detached;
115
116 u64 last_trans;
117
118 int nr_nodes;
119 int nr_edges;
120 };
121
122 /*
123 * map address of tree root to tree
124 */
125 struct mapping_node {
126 struct rb_node rb_node;
127 u64 bytenr;
128 void *data;
129 };
130
131 struct mapping_tree {
132 struct rb_root rb_root;
133 spinlock_t lock;
134 };
135
136 /*
137 * present a tree block to process
138 */
139 struct tree_block {
140 struct rb_node rb_node;
141 u64 bytenr;
142 struct btrfs_key key;
143 unsigned int level:8;
144 unsigned int key_ready:1;
145 };
146
147 #define MAX_EXTENTS 128
148
149 struct file_extent_cluster {
150 u64 start;
151 u64 end;
152 u64 boundary[MAX_EXTENTS];
153 unsigned int nr;
154 };
155
156 struct reloc_control {
157 /* block group to relocate */
158 struct btrfs_block_group_cache *block_group;
159 /* extent tree */
160 struct btrfs_root *extent_root;
161 /* inode for moving data */
162 struct inode *data_inode;
163
164 struct btrfs_block_rsv *block_rsv;
165
166 struct backref_cache backref_cache;
167
168 struct file_extent_cluster cluster;
169 /* tree blocks have been processed */
170 struct extent_io_tree processed_blocks;
171 /* map start of tree root to corresponding reloc tree */
172 struct mapping_tree reloc_root_tree;
173 /* list of reloc trees */
174 struct list_head reloc_roots;
175 /* size of metadata reservation for merging reloc trees */
176 u64 merging_rsv_size;
177 /* size of relocated tree nodes */
178 u64 nodes_relocated;
179
180 u64 search_start;
181 u64 extents_found;
182
183 unsigned int stage:8;
184 unsigned int create_reloc_tree:1;
185 unsigned int merge_reloc_tree:1;
186 unsigned int found_file_extent:1;
187 unsigned int commit_transaction:1;
188 };
189
190 /* stages of data relocation */
191 #define MOVE_DATA_EXTENTS 0
192 #define UPDATE_DATA_PTRS 1
193
194 static void remove_backref_node(struct backref_cache *cache,
195 struct backref_node *node);
196 static void __mark_block_processed(struct reloc_control *rc,
197 struct backref_node *node);
198
199 static void mapping_tree_init(struct mapping_tree *tree)
200 {
201 tree->rb_root = RB_ROOT;
202 spin_lock_init(&tree->lock);
203 }
204
205 static void backref_cache_init(struct backref_cache *cache)
206 {
207 int i;
208 cache->rb_root = RB_ROOT;
209 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
210 INIT_LIST_HEAD(&cache->pending[i]);
211 INIT_LIST_HEAD(&cache->changed);
212 INIT_LIST_HEAD(&cache->detached);
213 INIT_LIST_HEAD(&cache->leaves);
214 }
215
216 static void backref_cache_cleanup(struct backref_cache *cache)
217 {
218 struct backref_node *node;
219 int i;
220
221 while (!list_empty(&cache->detached)) {
222 node = list_entry(cache->detached.next,
223 struct backref_node, list);
224 remove_backref_node(cache, node);
225 }
226
227 while (!list_empty(&cache->leaves)) {
228 node = list_entry(cache->leaves.next,
229 struct backref_node, lower);
230 remove_backref_node(cache, node);
231 }
232
233 cache->last_trans = 0;
234
235 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
236 BUG_ON(!list_empty(&cache->pending[i]));
237 BUG_ON(!list_empty(&cache->changed));
238 BUG_ON(!list_empty(&cache->detached));
239 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
240 BUG_ON(cache->nr_nodes);
241 BUG_ON(cache->nr_edges);
242 }
243
244 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
245 {
246 struct backref_node *node;
247
248 node = kzalloc(sizeof(*node), GFP_NOFS);
249 if (node) {
250 INIT_LIST_HEAD(&node->list);
251 INIT_LIST_HEAD(&node->upper);
252 INIT_LIST_HEAD(&node->lower);
253 RB_CLEAR_NODE(&node->rb_node);
254 cache->nr_nodes++;
255 }
256 return node;
257 }
258
259 static void free_backref_node(struct backref_cache *cache,
260 struct backref_node *node)
261 {
262 if (node) {
263 cache->nr_nodes--;
264 kfree(node);
265 }
266 }
267
268 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
269 {
270 struct backref_edge *edge;
271
272 edge = kzalloc(sizeof(*edge), GFP_NOFS);
273 if (edge)
274 cache->nr_edges++;
275 return edge;
276 }
277
278 static void free_backref_edge(struct backref_cache *cache,
279 struct backref_edge *edge)
280 {
281 if (edge) {
282 cache->nr_edges--;
283 kfree(edge);
284 }
285 }
286
287 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
288 struct rb_node *node)
289 {
290 struct rb_node **p = &root->rb_node;
291 struct rb_node *parent = NULL;
292 struct tree_entry *entry;
293
294 while (*p) {
295 parent = *p;
296 entry = rb_entry(parent, struct tree_entry, rb_node);
297
298 if (bytenr < entry->bytenr)
299 p = &(*p)->rb_left;
300 else if (bytenr > entry->bytenr)
301 p = &(*p)->rb_right;
302 else
303 return parent;
304 }
305
306 rb_link_node(node, parent, p);
307 rb_insert_color(node, root);
308 return NULL;
309 }
310
311 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
312 {
313 struct rb_node *n = root->rb_node;
314 struct tree_entry *entry;
315
316 while (n) {
317 entry = rb_entry(n, struct tree_entry, rb_node);
318
319 if (bytenr < entry->bytenr)
320 n = n->rb_left;
321 else if (bytenr > entry->bytenr)
322 n = n->rb_right;
323 else
324 return n;
325 }
326 return NULL;
327 }
328
329 /*
330 * walk up backref nodes until reach node presents tree root
331 */
332 static struct backref_node *walk_up_backref(struct backref_node *node,
333 struct backref_edge *edges[],
334 int *index)
335 {
336 struct backref_edge *edge;
337 int idx = *index;
338
339 while (!list_empty(&node->upper)) {
340 edge = list_entry(node->upper.next,
341 struct backref_edge, list[LOWER]);
342 edges[idx++] = edge;
343 node = edge->node[UPPER];
344 }
345 BUG_ON(node->detached);
346 *index = idx;
347 return node;
348 }
349
350 /*
351 * walk down backref nodes to find start of next reference path
352 */
353 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
354 int *index)
355 {
356 struct backref_edge *edge;
357 struct backref_node *lower;
358 int idx = *index;
359
360 while (idx > 0) {
361 edge = edges[idx - 1];
362 lower = edge->node[LOWER];
363 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
364 idx--;
365 continue;
366 }
367 edge = list_entry(edge->list[LOWER].next,
368 struct backref_edge, list[LOWER]);
369 edges[idx - 1] = edge;
370 *index = idx;
371 return edge->node[UPPER];
372 }
373 *index = 0;
374 return NULL;
375 }
376
377 static void unlock_node_buffer(struct backref_node *node)
378 {
379 if (node->locked) {
380 btrfs_tree_unlock(node->eb);
381 node->locked = 0;
382 }
383 }
384
385 static void drop_node_buffer(struct backref_node *node)
386 {
387 if (node->eb) {
388 unlock_node_buffer(node);
389 free_extent_buffer(node->eb);
390 node->eb = NULL;
391 }
392 }
393
394 static void drop_backref_node(struct backref_cache *tree,
395 struct backref_node *node)
396 {
397 BUG_ON(!list_empty(&node->upper));
398
399 drop_node_buffer(node);
400 list_del(&node->list);
401 list_del(&node->lower);
402 if (!RB_EMPTY_NODE(&node->rb_node))
403 rb_erase(&node->rb_node, &tree->rb_root);
404 free_backref_node(tree, node);
405 }
406
407 /*
408 * remove a backref node from the backref cache
409 */
410 static void remove_backref_node(struct backref_cache *cache,
411 struct backref_node *node)
412 {
413 struct backref_node *upper;
414 struct backref_edge *edge;
415
416 if (!node)
417 return;
418
419 BUG_ON(!node->lowest && !node->detached);
420 while (!list_empty(&node->upper)) {
421 edge = list_entry(node->upper.next, struct backref_edge,
422 list[LOWER]);
423 upper = edge->node[UPPER];
424 list_del(&edge->list[LOWER]);
425 list_del(&edge->list[UPPER]);
426 free_backref_edge(cache, edge);
427
428 if (RB_EMPTY_NODE(&upper->rb_node)) {
429 BUG_ON(!list_empty(&node->upper));
430 drop_backref_node(cache, node);
431 node = upper;
432 node->lowest = 1;
433 continue;
434 }
435 /*
436 * add the node to leaf node list if no other
437 * child block cached.
438 */
439 if (list_empty(&upper->lower)) {
440 list_add_tail(&upper->lower, &cache->leaves);
441 upper->lowest = 1;
442 }
443 }
444
445 drop_backref_node(cache, node);
446 }
447
448 static void update_backref_node(struct backref_cache *cache,
449 struct backref_node *node, u64 bytenr)
450 {
451 struct rb_node *rb_node;
452 rb_erase(&node->rb_node, &cache->rb_root);
453 node->bytenr = bytenr;
454 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
455 BUG_ON(rb_node);
456 }
457
458 /*
459 * update backref cache after a transaction commit
460 */
461 static int update_backref_cache(struct btrfs_trans_handle *trans,
462 struct backref_cache *cache)
463 {
464 struct backref_node *node;
465 int level = 0;
466
467 if (cache->last_trans == 0) {
468 cache->last_trans = trans->transid;
469 return 0;
470 }
471
472 if (cache->last_trans == trans->transid)
473 return 0;
474
475 /*
476 * detached nodes are used to avoid unnecessary backref
477 * lookup. transaction commit changes the extent tree.
478 * so the detached nodes are no longer useful.
479 */
480 while (!list_empty(&cache->detached)) {
481 node = list_entry(cache->detached.next,
482 struct backref_node, list);
483 remove_backref_node(cache, node);
484 }
485
486 while (!list_empty(&cache->changed)) {
487 node = list_entry(cache->changed.next,
488 struct backref_node, list);
489 list_del_init(&node->list);
490 BUG_ON(node->pending);
491 update_backref_node(cache, node, node->new_bytenr);
492 }
493
494 /*
495 * some nodes can be left in the pending list if there were
496 * errors during processing the pending nodes.
497 */
498 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
499 list_for_each_entry(node, &cache->pending[level], list) {
500 BUG_ON(!node->pending);
501 if (node->bytenr == node->new_bytenr)
502 continue;
503 update_backref_node(cache, node, node->new_bytenr);
504 }
505 }
506
507 cache->last_trans = 0;
508 return 1;
509 }
510
511 static int should_ignore_root(struct btrfs_root *root)
512 {
513 struct btrfs_root *reloc_root;
514
515 if (!root->ref_cows)
516 return 0;
517
518 reloc_root = root->reloc_root;
519 if (!reloc_root)
520 return 0;
521
522 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
523 root->fs_info->running_transaction->transid - 1)
524 return 0;
525 /*
526 * if there is reloc tree and it was created in previous
527 * transaction backref lookup can find the reloc tree,
528 * so backref node for the fs tree root is useless for
529 * relocation.
530 */
531 return 1;
532 }
533
534 /*
535 * find reloc tree by address of tree root
536 */
537 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
538 u64 bytenr)
539 {
540 struct rb_node *rb_node;
541 struct mapping_node *node;
542 struct btrfs_root *root = NULL;
543
544 spin_lock(&rc->reloc_root_tree.lock);
545 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
546 if (rb_node) {
547 node = rb_entry(rb_node, struct mapping_node, rb_node);
548 root = (struct btrfs_root *)node->data;
549 }
550 spin_unlock(&rc->reloc_root_tree.lock);
551 return root;
552 }
553
554 static int is_cowonly_root(u64 root_objectid)
555 {
556 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
557 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
558 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
559 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
560 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
561 root_objectid == BTRFS_CSUM_TREE_OBJECTID)
562 return 1;
563 return 0;
564 }
565
566 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
567 u64 root_objectid)
568 {
569 struct btrfs_key key;
570
571 key.objectid = root_objectid;
572 key.type = BTRFS_ROOT_ITEM_KEY;
573 if (is_cowonly_root(root_objectid))
574 key.offset = 0;
575 else
576 key.offset = (u64)-1;
577
578 return btrfs_read_fs_root_no_name(fs_info, &key);
579 }
580
581 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
582 static noinline_for_stack
583 struct btrfs_root *find_tree_root(struct reloc_control *rc,
584 struct extent_buffer *leaf,
585 struct btrfs_extent_ref_v0 *ref0)
586 {
587 struct btrfs_root *root;
588 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
589 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
590
591 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
592
593 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
594 BUG_ON(IS_ERR(root));
595
596 if (root->ref_cows &&
597 generation != btrfs_root_generation(&root->root_item))
598 return NULL;
599
600 return root;
601 }
602 #endif
603
604 static noinline_for_stack
605 int find_inline_backref(struct extent_buffer *leaf, int slot,
606 unsigned long *ptr, unsigned long *end)
607 {
608 struct btrfs_extent_item *ei;
609 struct btrfs_tree_block_info *bi;
610 u32 item_size;
611
612 item_size = btrfs_item_size_nr(leaf, slot);
613 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
614 if (item_size < sizeof(*ei)) {
615 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
616 return 1;
617 }
618 #endif
619 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
620 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
621 BTRFS_EXTENT_FLAG_TREE_BLOCK));
622
623 if (item_size <= sizeof(*ei) + sizeof(*bi)) {
624 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
625 return 1;
626 }
627
628 bi = (struct btrfs_tree_block_info *)(ei + 1);
629 *ptr = (unsigned long)(bi + 1);
630 *end = (unsigned long)ei + item_size;
631 return 0;
632 }
633
634 /*
635 * build backref tree for a given tree block. root of the backref tree
636 * corresponds the tree block, leaves of the backref tree correspond
637 * roots of b-trees that reference the tree block.
638 *
639 * the basic idea of this function is check backrefs of a given block
640 * to find upper level blocks that refernece the block, and then check
641 * bakcrefs of these upper level blocks recursively. the recursion stop
642 * when tree root is reached or backrefs for the block is cached.
643 *
644 * NOTE: if we find backrefs for a block are cached, we know backrefs
645 * for all upper level blocks that directly/indirectly reference the
646 * block are also cached.
647 */
648 static noinline_for_stack
649 struct backref_node *build_backref_tree(struct reloc_control *rc,
650 struct btrfs_key *node_key,
651 int level, u64 bytenr)
652 {
653 struct backref_cache *cache = &rc->backref_cache;
654 struct btrfs_path *path1;
655 struct btrfs_path *path2;
656 struct extent_buffer *eb;
657 struct btrfs_root *root;
658 struct backref_node *cur;
659 struct backref_node *upper;
660 struct backref_node *lower;
661 struct backref_node *node = NULL;
662 struct backref_node *exist = NULL;
663 struct backref_edge *edge;
664 struct rb_node *rb_node;
665 struct btrfs_key key;
666 unsigned long end;
667 unsigned long ptr;
668 LIST_HEAD(list);
669 LIST_HEAD(useless);
670 int cowonly;
671 int ret;
672 int err = 0;
673
674 path1 = btrfs_alloc_path();
675 path2 = btrfs_alloc_path();
676 if (!path1 || !path2) {
677 err = -ENOMEM;
678 goto out;
679 }
680
681 node = alloc_backref_node(cache);
682 if (!node) {
683 err = -ENOMEM;
684 goto out;
685 }
686
687 node->bytenr = bytenr;
688 node->level = level;
689 node->lowest = 1;
690 cur = node;
691 again:
692 end = 0;
693 ptr = 0;
694 key.objectid = cur->bytenr;
695 key.type = BTRFS_EXTENT_ITEM_KEY;
696 key.offset = (u64)-1;
697
698 path1->search_commit_root = 1;
699 path1->skip_locking = 1;
700 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
701 0, 0);
702 if (ret < 0) {
703 err = ret;
704 goto out;
705 }
706 BUG_ON(!ret || !path1->slots[0]);
707
708 path1->slots[0]--;
709
710 WARN_ON(cur->checked);
711 if (!list_empty(&cur->upper)) {
712 /*
713 * the backref was added previously when processsing
714 * backref of type BTRFS_TREE_BLOCK_REF_KEY
715 */
716 BUG_ON(!list_is_singular(&cur->upper));
717 edge = list_entry(cur->upper.next, struct backref_edge,
718 list[LOWER]);
719 BUG_ON(!list_empty(&edge->list[UPPER]));
720 exist = edge->node[UPPER];
721 /*
722 * add the upper level block to pending list if we need
723 * check its backrefs
724 */
725 if (!exist->checked)
726 list_add_tail(&edge->list[UPPER], &list);
727 } else {
728 exist = NULL;
729 }
730
731 while (1) {
732 cond_resched();
733 eb = path1->nodes[0];
734
735 if (ptr >= end) {
736 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
737 ret = btrfs_next_leaf(rc->extent_root, path1);
738 if (ret < 0) {
739 err = ret;
740 goto out;
741 }
742 if (ret > 0)
743 break;
744 eb = path1->nodes[0];
745 }
746
747 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
748 if (key.objectid != cur->bytenr) {
749 WARN_ON(exist);
750 break;
751 }
752
753 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
754 ret = find_inline_backref(eb, path1->slots[0],
755 &ptr, &end);
756 if (ret)
757 goto next;
758 }
759 }
760
761 if (ptr < end) {
762 /* update key for inline back ref */
763 struct btrfs_extent_inline_ref *iref;
764 iref = (struct btrfs_extent_inline_ref *)ptr;
765 key.type = btrfs_extent_inline_ref_type(eb, iref);
766 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
767 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
768 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
769 }
770
771 if (exist &&
772 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
773 exist->owner == key.offset) ||
774 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
775 exist->bytenr == key.offset))) {
776 exist = NULL;
777 goto next;
778 }
779
780 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
781 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
782 key.type == BTRFS_EXTENT_REF_V0_KEY) {
783 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
784 struct btrfs_extent_ref_v0 *ref0;
785 ref0 = btrfs_item_ptr(eb, path1->slots[0],
786 struct btrfs_extent_ref_v0);
787 if (key.objectid == key.offset) {
788 root = find_tree_root(rc, eb, ref0);
789 if (root && !should_ignore_root(root))
790 cur->root = root;
791 else
792 list_add(&cur->list, &useless);
793 break;
794 }
795 if (is_cowonly_root(btrfs_ref_root_v0(eb,
796 ref0)))
797 cur->cowonly = 1;
798 }
799 #else
800 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
801 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
802 #endif
803 if (key.objectid == key.offset) {
804 /*
805 * only root blocks of reloc trees use
806 * backref of this type.
807 */
808 root = find_reloc_root(rc, cur->bytenr);
809 BUG_ON(!root);
810 cur->root = root;
811 break;
812 }
813
814 edge = alloc_backref_edge(cache);
815 if (!edge) {
816 err = -ENOMEM;
817 goto out;
818 }
819 rb_node = tree_search(&cache->rb_root, key.offset);
820 if (!rb_node) {
821 upper = alloc_backref_node(cache);
822 if (!upper) {
823 free_backref_edge(cache, edge);
824 err = -ENOMEM;
825 goto out;
826 }
827 upper->bytenr = key.offset;
828 upper->level = cur->level + 1;
829 /*
830 * backrefs for the upper level block isn't
831 * cached, add the block to pending list
832 */
833 list_add_tail(&edge->list[UPPER], &list);
834 } else {
835 upper = rb_entry(rb_node, struct backref_node,
836 rb_node);
837 BUG_ON(!upper->checked);
838 INIT_LIST_HEAD(&edge->list[UPPER]);
839 }
840 list_add_tail(&edge->list[LOWER], &cur->upper);
841 edge->node[LOWER] = cur;
842 edge->node[UPPER] = upper;
843
844 goto next;
845 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
846 goto next;
847 }
848
849 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
850 root = read_fs_root(rc->extent_root->fs_info, key.offset);
851 if (IS_ERR(root)) {
852 err = PTR_ERR(root);
853 goto out;
854 }
855
856 if (!root->ref_cows)
857 cur->cowonly = 1;
858
859 if (btrfs_root_level(&root->root_item) == cur->level) {
860 /* tree root */
861 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
862 cur->bytenr);
863 if (should_ignore_root(root))
864 list_add(&cur->list, &useless);
865 else
866 cur->root = root;
867 break;
868 }
869
870 level = cur->level + 1;
871
872 /*
873 * searching the tree to find upper level blocks
874 * reference the block.
875 */
876 path2->search_commit_root = 1;
877 path2->skip_locking = 1;
878 path2->lowest_level = level;
879 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
880 path2->lowest_level = 0;
881 if (ret < 0) {
882 err = ret;
883 goto out;
884 }
885 if (ret > 0 && path2->slots[level] > 0)
886 path2->slots[level]--;
887
888 eb = path2->nodes[level];
889 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
890 cur->bytenr);
891
892 lower = cur;
893 for (; level < BTRFS_MAX_LEVEL; level++) {
894 if (!path2->nodes[level]) {
895 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
896 lower->bytenr);
897 if (should_ignore_root(root))
898 list_add(&lower->list, &useless);
899 else
900 lower->root = root;
901 break;
902 }
903
904 edge = alloc_backref_edge(cache);
905 if (!edge) {
906 err = -ENOMEM;
907 goto out;
908 }
909
910 eb = path2->nodes[level];
911 rb_node = tree_search(&cache->rb_root, eb->start);
912 if (!rb_node) {
913 upper = alloc_backref_node(cache);
914 if (!upper) {
915 free_backref_edge(cache, edge);
916 err = -ENOMEM;
917 goto out;
918 }
919 upper->bytenr = eb->start;
920 upper->owner = btrfs_header_owner(eb);
921 upper->level = lower->level + 1;
922 if (!root->ref_cows)
923 upper->cowonly = 1;
924
925 /*
926 * if we know the block isn't shared
927 * we can void checking its backrefs.
928 */
929 if (btrfs_block_can_be_shared(root, eb))
930 upper->checked = 0;
931 else
932 upper->checked = 1;
933
934 /*
935 * add the block to pending list if we
936 * need check its backrefs. only block
937 * at 'cur->level + 1' is added to the
938 * tail of pending list. this guarantees
939 * we check backrefs from lower level
940 * blocks to upper level blocks.
941 */
942 if (!upper->checked &&
943 level == cur->level + 1) {
944 list_add_tail(&edge->list[UPPER],
945 &list);
946 } else
947 INIT_LIST_HEAD(&edge->list[UPPER]);
948 } else {
949 upper = rb_entry(rb_node, struct backref_node,
950 rb_node);
951 BUG_ON(!upper->checked);
952 INIT_LIST_HEAD(&edge->list[UPPER]);
953 if (!upper->owner)
954 upper->owner = btrfs_header_owner(eb);
955 }
956 list_add_tail(&edge->list[LOWER], &lower->upper);
957 edge->node[LOWER] = lower;
958 edge->node[UPPER] = upper;
959
960 if (rb_node)
961 break;
962 lower = upper;
963 upper = NULL;
964 }
965 btrfs_release_path(root, path2);
966 next:
967 if (ptr < end) {
968 ptr += btrfs_extent_inline_ref_size(key.type);
969 if (ptr >= end) {
970 WARN_ON(ptr > end);
971 ptr = 0;
972 end = 0;
973 }
974 }
975 if (ptr >= end)
976 path1->slots[0]++;
977 }
978 btrfs_release_path(rc->extent_root, path1);
979
980 cur->checked = 1;
981 WARN_ON(exist);
982
983 /* the pending list isn't empty, take the first block to process */
984 if (!list_empty(&list)) {
985 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
986 list_del_init(&edge->list[UPPER]);
987 cur = edge->node[UPPER];
988 goto again;
989 }
990
991 /*
992 * everything goes well, connect backref nodes and insert backref nodes
993 * into the cache.
994 */
995 BUG_ON(!node->checked);
996 cowonly = node->cowonly;
997 if (!cowonly) {
998 rb_node = tree_insert(&cache->rb_root, node->bytenr,
999 &node->rb_node);
1000 BUG_ON(rb_node);
1001 list_add_tail(&node->lower, &cache->leaves);
1002 }
1003
1004 list_for_each_entry(edge, &node->upper, list[LOWER])
1005 list_add_tail(&edge->list[UPPER], &list);
1006
1007 while (!list_empty(&list)) {
1008 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1009 list_del_init(&edge->list[UPPER]);
1010 upper = edge->node[UPPER];
1011 if (upper->detached) {
1012 list_del(&edge->list[LOWER]);
1013 lower = edge->node[LOWER];
1014 free_backref_edge(cache, edge);
1015 if (list_empty(&lower->upper))
1016 list_add(&lower->list, &useless);
1017 continue;
1018 }
1019
1020 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1021 if (upper->lowest) {
1022 list_del_init(&upper->lower);
1023 upper->lowest = 0;
1024 }
1025
1026 list_add_tail(&edge->list[UPPER], &upper->lower);
1027 continue;
1028 }
1029
1030 BUG_ON(!upper->checked);
1031 BUG_ON(cowonly != upper->cowonly);
1032 if (!cowonly) {
1033 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1034 &upper->rb_node);
1035 BUG_ON(rb_node);
1036 }
1037
1038 list_add_tail(&edge->list[UPPER], &upper->lower);
1039
1040 list_for_each_entry(edge, &upper->upper, list[LOWER])
1041 list_add_tail(&edge->list[UPPER], &list);
1042 }
1043 /*
1044 * process useless backref nodes. backref nodes for tree leaves
1045 * are deleted from the cache. backref nodes for upper level
1046 * tree blocks are left in the cache to avoid unnecessary backref
1047 * lookup.
1048 */
1049 while (!list_empty(&useless)) {
1050 upper = list_entry(useless.next, struct backref_node, list);
1051 list_del_init(&upper->list);
1052 BUG_ON(!list_empty(&upper->upper));
1053 if (upper == node)
1054 node = NULL;
1055 if (upper->lowest) {
1056 list_del_init(&upper->lower);
1057 upper->lowest = 0;
1058 }
1059 while (!list_empty(&upper->lower)) {
1060 edge = list_entry(upper->lower.next,
1061 struct backref_edge, list[UPPER]);
1062 list_del(&edge->list[UPPER]);
1063 list_del(&edge->list[LOWER]);
1064 lower = edge->node[LOWER];
1065 free_backref_edge(cache, edge);
1066
1067 if (list_empty(&lower->upper))
1068 list_add(&lower->list, &useless);
1069 }
1070 __mark_block_processed(rc, upper);
1071 if (upper->level > 0) {
1072 list_add(&upper->list, &cache->detached);
1073 upper->detached = 1;
1074 } else {
1075 rb_erase(&upper->rb_node, &cache->rb_root);
1076 free_backref_node(cache, upper);
1077 }
1078 }
1079 out:
1080 btrfs_free_path(path1);
1081 btrfs_free_path(path2);
1082 if (err) {
1083 while (!list_empty(&useless)) {
1084 lower = list_entry(useless.next,
1085 struct backref_node, upper);
1086 list_del_init(&lower->upper);
1087 }
1088 upper = node;
1089 INIT_LIST_HEAD(&list);
1090 while (upper) {
1091 if (RB_EMPTY_NODE(&upper->rb_node)) {
1092 list_splice_tail(&upper->upper, &list);
1093 free_backref_node(cache, upper);
1094 }
1095
1096 if (list_empty(&list))
1097 break;
1098
1099 edge = list_entry(list.next, struct backref_edge,
1100 list[LOWER]);
1101 list_del(&edge->list[LOWER]);
1102 upper = edge->node[UPPER];
1103 free_backref_edge(cache, edge);
1104 }
1105 return ERR_PTR(err);
1106 }
1107 BUG_ON(node && node->detached);
1108 return node;
1109 }
1110
1111 /*
1112 * helper to add backref node for the newly created snapshot.
1113 * the backref node is created by cloning backref node that
1114 * corresponds to root of source tree
1115 */
1116 static int clone_backref_node(struct btrfs_trans_handle *trans,
1117 struct reloc_control *rc,
1118 struct btrfs_root *src,
1119 struct btrfs_root *dest)
1120 {
1121 struct btrfs_root *reloc_root = src->reloc_root;
1122 struct backref_cache *cache = &rc->backref_cache;
1123 struct backref_node *node = NULL;
1124 struct backref_node *new_node;
1125 struct backref_edge *edge;
1126 struct backref_edge *new_edge;
1127 struct rb_node *rb_node;
1128
1129 if (cache->last_trans > 0)
1130 update_backref_cache(trans, cache);
1131
1132 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1133 if (rb_node) {
1134 node = rb_entry(rb_node, struct backref_node, rb_node);
1135 if (node->detached)
1136 node = NULL;
1137 else
1138 BUG_ON(node->new_bytenr != reloc_root->node->start);
1139 }
1140
1141 if (!node) {
1142 rb_node = tree_search(&cache->rb_root,
1143 reloc_root->commit_root->start);
1144 if (rb_node) {
1145 node = rb_entry(rb_node, struct backref_node,
1146 rb_node);
1147 BUG_ON(node->detached);
1148 }
1149 }
1150
1151 if (!node)
1152 return 0;
1153
1154 new_node = alloc_backref_node(cache);
1155 if (!new_node)
1156 return -ENOMEM;
1157
1158 new_node->bytenr = dest->node->start;
1159 new_node->level = node->level;
1160 new_node->lowest = node->lowest;
1161 new_node->checked = 1;
1162 new_node->root = dest;
1163
1164 if (!node->lowest) {
1165 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1166 new_edge = alloc_backref_edge(cache);
1167 if (!new_edge)
1168 goto fail;
1169
1170 new_edge->node[UPPER] = new_node;
1171 new_edge->node[LOWER] = edge->node[LOWER];
1172 list_add_tail(&new_edge->list[UPPER],
1173 &new_node->lower);
1174 }
1175 }
1176
1177 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1178 &new_node->rb_node);
1179 BUG_ON(rb_node);
1180
1181 if (!new_node->lowest) {
1182 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1183 list_add_tail(&new_edge->list[LOWER],
1184 &new_edge->node[LOWER]->upper);
1185 }
1186 }
1187 return 0;
1188 fail:
1189 while (!list_empty(&new_node->lower)) {
1190 new_edge = list_entry(new_node->lower.next,
1191 struct backref_edge, list[UPPER]);
1192 list_del(&new_edge->list[UPPER]);
1193 free_backref_edge(cache, new_edge);
1194 }
1195 free_backref_node(cache, new_node);
1196 return -ENOMEM;
1197 }
1198
1199 /*
1200 * helper to add 'address of tree root -> reloc tree' mapping
1201 */
1202 static int __add_reloc_root(struct btrfs_root *root)
1203 {
1204 struct rb_node *rb_node;
1205 struct mapping_node *node;
1206 struct reloc_control *rc = root->fs_info->reloc_ctl;
1207
1208 node = kmalloc(sizeof(*node), GFP_NOFS);
1209 BUG_ON(!node);
1210
1211 node->bytenr = root->node->start;
1212 node->data = root;
1213
1214 spin_lock(&rc->reloc_root_tree.lock);
1215 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1216 node->bytenr, &node->rb_node);
1217 spin_unlock(&rc->reloc_root_tree.lock);
1218 BUG_ON(rb_node);
1219
1220 list_add_tail(&root->root_list, &rc->reloc_roots);
1221 return 0;
1222 }
1223
1224 /*
1225 * helper to update/delete the 'address of tree root -> reloc tree'
1226 * mapping
1227 */
1228 static int __update_reloc_root(struct btrfs_root *root, int del)
1229 {
1230 struct rb_node *rb_node;
1231 struct mapping_node *node = NULL;
1232 struct reloc_control *rc = root->fs_info->reloc_ctl;
1233
1234 spin_lock(&rc->reloc_root_tree.lock);
1235 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1236 root->commit_root->start);
1237 if (rb_node) {
1238 node = rb_entry(rb_node, struct mapping_node, rb_node);
1239 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1240 }
1241 spin_unlock(&rc->reloc_root_tree.lock);
1242
1243 BUG_ON((struct btrfs_root *)node->data != root);
1244
1245 if (!del) {
1246 spin_lock(&rc->reloc_root_tree.lock);
1247 node->bytenr = root->node->start;
1248 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1249 node->bytenr, &node->rb_node);
1250 spin_unlock(&rc->reloc_root_tree.lock);
1251 BUG_ON(rb_node);
1252 } else {
1253 list_del_init(&root->root_list);
1254 kfree(node);
1255 }
1256 return 0;
1257 }
1258
1259 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1260 struct btrfs_root *root, u64 objectid)
1261 {
1262 struct btrfs_root *reloc_root;
1263 struct extent_buffer *eb;
1264 struct btrfs_root_item *root_item;
1265 struct btrfs_key root_key;
1266 int ret;
1267
1268 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1269 BUG_ON(!root_item);
1270
1271 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1272 root_key.type = BTRFS_ROOT_ITEM_KEY;
1273 root_key.offset = objectid;
1274
1275 if (root->root_key.objectid == objectid) {
1276 /* called by btrfs_init_reloc_root */
1277 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1278 BTRFS_TREE_RELOC_OBJECTID);
1279 BUG_ON(ret);
1280
1281 btrfs_set_root_last_snapshot(&root->root_item,
1282 trans->transid - 1);
1283 } else {
1284 /*
1285 * called by btrfs_reloc_post_snapshot_hook.
1286 * the source tree is a reloc tree, all tree blocks
1287 * modified after it was created have RELOC flag
1288 * set in their headers. so it's OK to not update
1289 * the 'last_snapshot'.
1290 */
1291 ret = btrfs_copy_root(trans, root, root->node, &eb,
1292 BTRFS_TREE_RELOC_OBJECTID);
1293 BUG_ON(ret);
1294 }
1295
1296 memcpy(root_item, &root->root_item, sizeof(*root_item));
1297 btrfs_set_root_bytenr(root_item, eb->start);
1298 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1299 btrfs_set_root_generation(root_item, trans->transid);
1300
1301 if (root->root_key.objectid == objectid) {
1302 btrfs_set_root_refs(root_item, 0);
1303 memset(&root_item->drop_progress, 0,
1304 sizeof(struct btrfs_disk_key));
1305 root_item->drop_level = 0;
1306 }
1307
1308 btrfs_tree_unlock(eb);
1309 free_extent_buffer(eb);
1310
1311 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1312 &root_key, root_item);
1313 BUG_ON(ret);
1314 kfree(root_item);
1315
1316 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
1317 &root_key);
1318 BUG_ON(IS_ERR(reloc_root));
1319 reloc_root->last_trans = trans->transid;
1320 return reloc_root;
1321 }
1322
1323 /*
1324 * create reloc tree for a given fs tree. reloc tree is just a
1325 * snapshot of the fs tree with special root objectid.
1326 */
1327 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1328 struct btrfs_root *root)
1329 {
1330 struct btrfs_root *reloc_root;
1331 struct reloc_control *rc = root->fs_info->reloc_ctl;
1332 int clear_rsv = 0;
1333
1334 if (root->reloc_root) {
1335 reloc_root = root->reloc_root;
1336 reloc_root->last_trans = trans->transid;
1337 return 0;
1338 }
1339
1340 if (!rc || !rc->create_reloc_tree ||
1341 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1342 return 0;
1343
1344 if (!trans->block_rsv) {
1345 trans->block_rsv = rc->block_rsv;
1346 clear_rsv = 1;
1347 }
1348 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1349 if (clear_rsv)
1350 trans->block_rsv = NULL;
1351
1352 __add_reloc_root(reloc_root);
1353 root->reloc_root = reloc_root;
1354 return 0;
1355 }
1356
1357 /*
1358 * update root item of reloc tree
1359 */
1360 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1361 struct btrfs_root *root)
1362 {
1363 struct btrfs_root *reloc_root;
1364 struct btrfs_root_item *root_item;
1365 int del = 0;
1366 int ret;
1367
1368 if (!root->reloc_root)
1369 return 0;
1370
1371 reloc_root = root->reloc_root;
1372 root_item = &reloc_root->root_item;
1373
1374 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1375 btrfs_root_refs(root_item) == 0) {
1376 root->reloc_root = NULL;
1377 del = 1;
1378 }
1379
1380 __update_reloc_root(reloc_root, del);
1381
1382 if (reloc_root->commit_root != reloc_root->node) {
1383 btrfs_set_root_node(root_item, reloc_root->node);
1384 free_extent_buffer(reloc_root->commit_root);
1385 reloc_root->commit_root = btrfs_root_node(reloc_root);
1386 }
1387
1388 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1389 &reloc_root->root_key, root_item);
1390 BUG_ON(ret);
1391 return 0;
1392 }
1393
1394 /*
1395 * helper to find first cached inode with inode number >= objectid
1396 * in a subvolume
1397 */
1398 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1399 {
1400 struct rb_node *node;
1401 struct rb_node *prev;
1402 struct btrfs_inode *entry;
1403 struct inode *inode;
1404
1405 spin_lock(&root->inode_lock);
1406 again:
1407 node = root->inode_tree.rb_node;
1408 prev = NULL;
1409 while (node) {
1410 prev = node;
1411 entry = rb_entry(node, struct btrfs_inode, rb_node);
1412
1413 if (objectid < btrfs_ino(&entry->vfs_inode))
1414 node = node->rb_left;
1415 else if (objectid > btrfs_ino(&entry->vfs_inode))
1416 node = node->rb_right;
1417 else
1418 break;
1419 }
1420 if (!node) {
1421 while (prev) {
1422 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1423 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1424 node = prev;
1425 break;
1426 }
1427 prev = rb_next(prev);
1428 }
1429 }
1430 while (node) {
1431 entry = rb_entry(node, struct btrfs_inode, rb_node);
1432 inode = igrab(&entry->vfs_inode);
1433 if (inode) {
1434 spin_unlock(&root->inode_lock);
1435 return inode;
1436 }
1437
1438 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1439 if (cond_resched_lock(&root->inode_lock))
1440 goto again;
1441
1442 node = rb_next(node);
1443 }
1444 spin_unlock(&root->inode_lock);
1445 return NULL;
1446 }
1447
1448 static int in_block_group(u64 bytenr,
1449 struct btrfs_block_group_cache *block_group)
1450 {
1451 if (bytenr >= block_group->key.objectid &&
1452 bytenr < block_group->key.objectid + block_group->key.offset)
1453 return 1;
1454 return 0;
1455 }
1456
1457 /*
1458 * get new location of data
1459 */
1460 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1461 u64 bytenr, u64 num_bytes)
1462 {
1463 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1464 struct btrfs_path *path;
1465 struct btrfs_file_extent_item *fi;
1466 struct extent_buffer *leaf;
1467 int ret;
1468
1469 path = btrfs_alloc_path();
1470 if (!path)
1471 return -ENOMEM;
1472
1473 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1474 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1475 bytenr, 0);
1476 if (ret < 0)
1477 goto out;
1478 if (ret > 0) {
1479 ret = -ENOENT;
1480 goto out;
1481 }
1482
1483 leaf = path->nodes[0];
1484 fi = btrfs_item_ptr(leaf, path->slots[0],
1485 struct btrfs_file_extent_item);
1486
1487 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1488 btrfs_file_extent_compression(leaf, fi) ||
1489 btrfs_file_extent_encryption(leaf, fi) ||
1490 btrfs_file_extent_other_encoding(leaf, fi));
1491
1492 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1493 ret = 1;
1494 goto out;
1495 }
1496
1497 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1498 ret = 0;
1499 out:
1500 btrfs_free_path(path);
1501 return ret;
1502 }
1503
1504 /*
1505 * update file extent items in the tree leaf to point to
1506 * the new locations.
1507 */
1508 static noinline_for_stack
1509 int replace_file_extents(struct btrfs_trans_handle *trans,
1510 struct reloc_control *rc,
1511 struct btrfs_root *root,
1512 struct extent_buffer *leaf)
1513 {
1514 struct btrfs_key key;
1515 struct btrfs_file_extent_item *fi;
1516 struct inode *inode = NULL;
1517 u64 parent;
1518 u64 bytenr;
1519 u64 new_bytenr = 0;
1520 u64 num_bytes;
1521 u64 end;
1522 u32 nritems;
1523 u32 i;
1524 int ret;
1525 int first = 1;
1526 int dirty = 0;
1527
1528 if (rc->stage != UPDATE_DATA_PTRS)
1529 return 0;
1530
1531 /* reloc trees always use full backref */
1532 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1533 parent = leaf->start;
1534 else
1535 parent = 0;
1536
1537 nritems = btrfs_header_nritems(leaf);
1538 for (i = 0; i < nritems; i++) {
1539 cond_resched();
1540 btrfs_item_key_to_cpu(leaf, &key, i);
1541 if (key.type != BTRFS_EXTENT_DATA_KEY)
1542 continue;
1543 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1544 if (btrfs_file_extent_type(leaf, fi) ==
1545 BTRFS_FILE_EXTENT_INLINE)
1546 continue;
1547 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1548 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1549 if (bytenr == 0)
1550 continue;
1551 if (!in_block_group(bytenr, rc->block_group))
1552 continue;
1553
1554 /*
1555 * if we are modifying block in fs tree, wait for readpage
1556 * to complete and drop the extent cache
1557 */
1558 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1559 if (first) {
1560 inode = find_next_inode(root, key.objectid);
1561 first = 0;
1562 } else if (inode && btrfs_ino(inode) < key.objectid) {
1563 btrfs_add_delayed_iput(inode);
1564 inode = find_next_inode(root, key.objectid);
1565 }
1566 if (inode && btrfs_ino(inode) == key.objectid) {
1567 end = key.offset +
1568 btrfs_file_extent_num_bytes(leaf, fi);
1569 WARN_ON(!IS_ALIGNED(key.offset,
1570 root->sectorsize));
1571 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1572 end--;
1573 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1574 key.offset, end,
1575 GFP_NOFS);
1576 if (!ret)
1577 continue;
1578
1579 btrfs_drop_extent_cache(inode, key.offset, end,
1580 1);
1581 unlock_extent(&BTRFS_I(inode)->io_tree,
1582 key.offset, end, GFP_NOFS);
1583 }
1584 }
1585
1586 ret = get_new_location(rc->data_inode, &new_bytenr,
1587 bytenr, num_bytes);
1588 if (ret > 0) {
1589 WARN_ON(1);
1590 continue;
1591 }
1592 BUG_ON(ret < 0);
1593
1594 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1595 dirty = 1;
1596
1597 key.offset -= btrfs_file_extent_offset(leaf, fi);
1598 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1599 num_bytes, parent,
1600 btrfs_header_owner(leaf),
1601 key.objectid, key.offset);
1602 BUG_ON(ret);
1603
1604 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1605 parent, btrfs_header_owner(leaf),
1606 key.objectid, key.offset);
1607 BUG_ON(ret);
1608 }
1609 if (dirty)
1610 btrfs_mark_buffer_dirty(leaf);
1611 if (inode)
1612 btrfs_add_delayed_iput(inode);
1613 return 0;
1614 }
1615
1616 static noinline_for_stack
1617 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1618 struct btrfs_path *path, int level)
1619 {
1620 struct btrfs_disk_key key1;
1621 struct btrfs_disk_key key2;
1622 btrfs_node_key(eb, &key1, slot);
1623 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1624 return memcmp(&key1, &key2, sizeof(key1));
1625 }
1626
1627 /*
1628 * try to replace tree blocks in fs tree with the new blocks
1629 * in reloc tree. tree blocks haven't been modified since the
1630 * reloc tree was create can be replaced.
1631 *
1632 * if a block was replaced, level of the block + 1 is returned.
1633 * if no block got replaced, 0 is returned. if there are other
1634 * errors, a negative error number is returned.
1635 */
1636 static noinline_for_stack
1637 int replace_path(struct btrfs_trans_handle *trans,
1638 struct btrfs_root *dest, struct btrfs_root *src,
1639 struct btrfs_path *path, struct btrfs_key *next_key,
1640 int lowest_level, int max_level)
1641 {
1642 struct extent_buffer *eb;
1643 struct extent_buffer *parent;
1644 struct btrfs_key key;
1645 u64 old_bytenr;
1646 u64 new_bytenr;
1647 u64 old_ptr_gen;
1648 u64 new_ptr_gen;
1649 u64 last_snapshot;
1650 u32 blocksize;
1651 int cow = 0;
1652 int level;
1653 int ret;
1654 int slot;
1655
1656 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1657 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1658
1659 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1660 again:
1661 slot = path->slots[lowest_level];
1662 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1663
1664 eb = btrfs_lock_root_node(dest);
1665 btrfs_set_lock_blocking(eb);
1666 level = btrfs_header_level(eb);
1667
1668 if (level < lowest_level) {
1669 btrfs_tree_unlock(eb);
1670 free_extent_buffer(eb);
1671 return 0;
1672 }
1673
1674 if (cow) {
1675 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1676 BUG_ON(ret);
1677 }
1678 btrfs_set_lock_blocking(eb);
1679
1680 if (next_key) {
1681 next_key->objectid = (u64)-1;
1682 next_key->type = (u8)-1;
1683 next_key->offset = (u64)-1;
1684 }
1685
1686 parent = eb;
1687 while (1) {
1688 level = btrfs_header_level(parent);
1689 BUG_ON(level < lowest_level);
1690
1691 ret = btrfs_bin_search(parent, &key, level, &slot);
1692 if (ret && slot > 0)
1693 slot--;
1694
1695 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1696 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1697
1698 old_bytenr = btrfs_node_blockptr(parent, slot);
1699 blocksize = btrfs_level_size(dest, level - 1);
1700 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1701
1702 if (level <= max_level) {
1703 eb = path->nodes[level];
1704 new_bytenr = btrfs_node_blockptr(eb,
1705 path->slots[level]);
1706 new_ptr_gen = btrfs_node_ptr_generation(eb,
1707 path->slots[level]);
1708 } else {
1709 new_bytenr = 0;
1710 new_ptr_gen = 0;
1711 }
1712
1713 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1714 WARN_ON(1);
1715 ret = level;
1716 break;
1717 }
1718
1719 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1720 memcmp_node_keys(parent, slot, path, level)) {
1721 if (level <= lowest_level) {
1722 ret = 0;
1723 break;
1724 }
1725
1726 eb = read_tree_block(dest, old_bytenr, blocksize,
1727 old_ptr_gen);
1728 BUG_ON(!eb);
1729 btrfs_tree_lock(eb);
1730 if (cow) {
1731 ret = btrfs_cow_block(trans, dest, eb, parent,
1732 slot, &eb);
1733 BUG_ON(ret);
1734 }
1735 btrfs_set_lock_blocking(eb);
1736
1737 btrfs_tree_unlock(parent);
1738 free_extent_buffer(parent);
1739
1740 parent = eb;
1741 continue;
1742 }
1743
1744 if (!cow) {
1745 btrfs_tree_unlock(parent);
1746 free_extent_buffer(parent);
1747 cow = 1;
1748 goto again;
1749 }
1750
1751 btrfs_node_key_to_cpu(path->nodes[level], &key,
1752 path->slots[level]);
1753 btrfs_release_path(src, path);
1754
1755 path->lowest_level = level;
1756 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1757 path->lowest_level = 0;
1758 BUG_ON(ret);
1759
1760 /*
1761 * swap blocks in fs tree and reloc tree.
1762 */
1763 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1764 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1765 btrfs_mark_buffer_dirty(parent);
1766
1767 btrfs_set_node_blockptr(path->nodes[level],
1768 path->slots[level], old_bytenr);
1769 btrfs_set_node_ptr_generation(path->nodes[level],
1770 path->slots[level], old_ptr_gen);
1771 btrfs_mark_buffer_dirty(path->nodes[level]);
1772
1773 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1774 path->nodes[level]->start,
1775 src->root_key.objectid, level - 1, 0);
1776 BUG_ON(ret);
1777 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1778 0, dest->root_key.objectid, level - 1,
1779 0);
1780 BUG_ON(ret);
1781
1782 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1783 path->nodes[level]->start,
1784 src->root_key.objectid, level - 1, 0);
1785 BUG_ON(ret);
1786
1787 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1788 0, dest->root_key.objectid, level - 1,
1789 0);
1790 BUG_ON(ret);
1791
1792 btrfs_unlock_up_safe(path, 0);
1793
1794 ret = level;
1795 break;
1796 }
1797 btrfs_tree_unlock(parent);
1798 free_extent_buffer(parent);
1799 return ret;
1800 }
1801
1802 /*
1803 * helper to find next relocated block in reloc tree
1804 */
1805 static noinline_for_stack
1806 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1807 int *level)
1808 {
1809 struct extent_buffer *eb;
1810 int i;
1811 u64 last_snapshot;
1812 u32 nritems;
1813
1814 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1815
1816 for (i = 0; i < *level; i++) {
1817 free_extent_buffer(path->nodes[i]);
1818 path->nodes[i] = NULL;
1819 }
1820
1821 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1822 eb = path->nodes[i];
1823 nritems = btrfs_header_nritems(eb);
1824 while (path->slots[i] + 1 < nritems) {
1825 path->slots[i]++;
1826 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1827 last_snapshot)
1828 continue;
1829
1830 *level = i;
1831 return 0;
1832 }
1833 free_extent_buffer(path->nodes[i]);
1834 path->nodes[i] = NULL;
1835 }
1836 return 1;
1837 }
1838
1839 /*
1840 * walk down reloc tree to find relocated block of lowest level
1841 */
1842 static noinline_for_stack
1843 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1844 int *level)
1845 {
1846 struct extent_buffer *eb = NULL;
1847 int i;
1848 u64 bytenr;
1849 u64 ptr_gen = 0;
1850 u64 last_snapshot;
1851 u32 blocksize;
1852 u32 nritems;
1853
1854 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1855
1856 for (i = *level; i > 0; i--) {
1857 eb = path->nodes[i];
1858 nritems = btrfs_header_nritems(eb);
1859 while (path->slots[i] < nritems) {
1860 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1861 if (ptr_gen > last_snapshot)
1862 break;
1863 path->slots[i]++;
1864 }
1865 if (path->slots[i] >= nritems) {
1866 if (i == *level)
1867 break;
1868 *level = i + 1;
1869 return 0;
1870 }
1871 if (i == 1) {
1872 *level = i;
1873 return 0;
1874 }
1875
1876 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1877 blocksize = btrfs_level_size(root, i - 1);
1878 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1879 BUG_ON(btrfs_header_level(eb) != i - 1);
1880 path->nodes[i - 1] = eb;
1881 path->slots[i - 1] = 0;
1882 }
1883 return 1;
1884 }
1885
1886 /*
1887 * invalidate extent cache for file extents whose key in range of
1888 * [min_key, max_key)
1889 */
1890 static int invalidate_extent_cache(struct btrfs_root *root,
1891 struct btrfs_key *min_key,
1892 struct btrfs_key *max_key)
1893 {
1894 struct inode *inode = NULL;
1895 u64 objectid;
1896 u64 start, end;
1897 u64 ino;
1898
1899 objectid = min_key->objectid;
1900 while (1) {
1901 cond_resched();
1902 iput(inode);
1903
1904 if (objectid > max_key->objectid)
1905 break;
1906
1907 inode = find_next_inode(root, objectid);
1908 if (!inode)
1909 break;
1910 ino = btrfs_ino(inode);
1911
1912 if (ino > max_key->objectid) {
1913 iput(inode);
1914 break;
1915 }
1916
1917 objectid = ino + 1;
1918 if (!S_ISREG(inode->i_mode))
1919 continue;
1920
1921 if (unlikely(min_key->objectid == ino)) {
1922 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1923 continue;
1924 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1925 start = 0;
1926 else {
1927 start = min_key->offset;
1928 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1929 }
1930 } else {
1931 start = 0;
1932 }
1933
1934 if (unlikely(max_key->objectid == ino)) {
1935 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1936 continue;
1937 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1938 end = (u64)-1;
1939 } else {
1940 if (max_key->offset == 0)
1941 continue;
1942 end = max_key->offset;
1943 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1944 end--;
1945 }
1946 } else {
1947 end = (u64)-1;
1948 }
1949
1950 /* the lock_extent waits for readpage to complete */
1951 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1952 btrfs_drop_extent_cache(inode, start, end, 1);
1953 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1954 }
1955 return 0;
1956 }
1957
1958 static int find_next_key(struct btrfs_path *path, int level,
1959 struct btrfs_key *key)
1960
1961 {
1962 while (level < BTRFS_MAX_LEVEL) {
1963 if (!path->nodes[level])
1964 break;
1965 if (path->slots[level] + 1 <
1966 btrfs_header_nritems(path->nodes[level])) {
1967 btrfs_node_key_to_cpu(path->nodes[level], key,
1968 path->slots[level] + 1);
1969 return 0;
1970 }
1971 level++;
1972 }
1973 return 1;
1974 }
1975
1976 /*
1977 * merge the relocated tree blocks in reloc tree with corresponding
1978 * fs tree.
1979 */
1980 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1981 struct btrfs_root *root)
1982 {
1983 LIST_HEAD(inode_list);
1984 struct btrfs_key key;
1985 struct btrfs_key next_key;
1986 struct btrfs_trans_handle *trans;
1987 struct btrfs_root *reloc_root;
1988 struct btrfs_root_item *root_item;
1989 struct btrfs_path *path;
1990 struct extent_buffer *leaf;
1991 unsigned long nr;
1992 int level;
1993 int max_level;
1994 int replaced = 0;
1995 int ret;
1996 int err = 0;
1997 u32 min_reserved;
1998
1999 path = btrfs_alloc_path();
2000 if (!path)
2001 return -ENOMEM;
2002
2003 reloc_root = root->reloc_root;
2004 root_item = &reloc_root->root_item;
2005
2006 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2007 level = btrfs_root_level(root_item);
2008 extent_buffer_get(reloc_root->node);
2009 path->nodes[level] = reloc_root->node;
2010 path->slots[level] = 0;
2011 } else {
2012 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2013
2014 level = root_item->drop_level;
2015 BUG_ON(level == 0);
2016 path->lowest_level = level;
2017 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2018 path->lowest_level = 0;
2019 if (ret < 0) {
2020 btrfs_free_path(path);
2021 return ret;
2022 }
2023
2024 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2025 path->slots[level]);
2026 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2027
2028 btrfs_unlock_up_safe(path, 0);
2029 }
2030
2031 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2032 memset(&next_key, 0, sizeof(next_key));
2033
2034 while (1) {
2035 trans = btrfs_start_transaction(root, 0);
2036 BUG_ON(IS_ERR(trans));
2037 trans->block_rsv = rc->block_rsv;
2038
2039 ret = btrfs_block_rsv_check(trans, root, rc->block_rsv,
2040 min_reserved, 0);
2041 if (ret) {
2042 BUG_ON(ret != -EAGAIN);
2043 ret = btrfs_commit_transaction(trans, root);
2044 BUG_ON(ret);
2045 continue;
2046 }
2047
2048 replaced = 0;
2049 max_level = level;
2050
2051 ret = walk_down_reloc_tree(reloc_root, path, &level);
2052 if (ret < 0) {
2053 err = ret;
2054 goto out;
2055 }
2056 if (ret > 0)
2057 break;
2058
2059 if (!find_next_key(path, level, &key) &&
2060 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2061 ret = 0;
2062 } else {
2063 ret = replace_path(trans, root, reloc_root, path,
2064 &next_key, level, max_level);
2065 }
2066 if (ret < 0) {
2067 err = ret;
2068 goto out;
2069 }
2070
2071 if (ret > 0) {
2072 level = ret;
2073 btrfs_node_key_to_cpu(path->nodes[level], &key,
2074 path->slots[level]);
2075 replaced = 1;
2076 }
2077
2078 ret = walk_up_reloc_tree(reloc_root, path, &level);
2079 if (ret > 0)
2080 break;
2081
2082 BUG_ON(level == 0);
2083 /*
2084 * save the merging progress in the drop_progress.
2085 * this is OK since root refs == 1 in this case.
2086 */
2087 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2088 path->slots[level]);
2089 root_item->drop_level = level;
2090
2091 nr = trans->blocks_used;
2092 btrfs_end_transaction_throttle(trans, root);
2093
2094 btrfs_btree_balance_dirty(root, nr);
2095
2096 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2097 invalidate_extent_cache(root, &key, &next_key);
2098 }
2099
2100 /*
2101 * handle the case only one block in the fs tree need to be
2102 * relocated and the block is tree root.
2103 */
2104 leaf = btrfs_lock_root_node(root);
2105 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2106 btrfs_tree_unlock(leaf);
2107 free_extent_buffer(leaf);
2108 if (ret < 0)
2109 err = ret;
2110 out:
2111 btrfs_free_path(path);
2112
2113 if (err == 0) {
2114 memset(&root_item->drop_progress, 0,
2115 sizeof(root_item->drop_progress));
2116 root_item->drop_level = 0;
2117 btrfs_set_root_refs(root_item, 0);
2118 btrfs_update_reloc_root(trans, root);
2119 }
2120
2121 nr = trans->blocks_used;
2122 btrfs_end_transaction_throttle(trans, root);
2123
2124 btrfs_btree_balance_dirty(root, nr);
2125
2126 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2127 invalidate_extent_cache(root, &key, &next_key);
2128
2129 return err;
2130 }
2131
2132 static noinline_for_stack
2133 int prepare_to_merge(struct reloc_control *rc, int err)
2134 {
2135 struct btrfs_root *root = rc->extent_root;
2136 struct btrfs_root *reloc_root;
2137 struct btrfs_trans_handle *trans;
2138 LIST_HEAD(reloc_roots);
2139 u64 num_bytes = 0;
2140 int ret;
2141
2142 mutex_lock(&root->fs_info->trans_mutex);
2143 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2144 rc->merging_rsv_size += rc->nodes_relocated * 2;
2145 mutex_unlock(&root->fs_info->trans_mutex);
2146 again:
2147 if (!err) {
2148 num_bytes = rc->merging_rsv_size;
2149 ret = btrfs_block_rsv_add(NULL, root, rc->block_rsv,
2150 num_bytes);
2151 if (ret)
2152 err = ret;
2153 }
2154
2155 trans = btrfs_join_transaction(rc->extent_root, 1);
2156 if (IS_ERR(trans)) {
2157 if (!err)
2158 btrfs_block_rsv_release(rc->extent_root,
2159 rc->block_rsv, num_bytes);
2160 return PTR_ERR(trans);
2161 }
2162
2163 if (!err) {
2164 if (num_bytes != rc->merging_rsv_size) {
2165 btrfs_end_transaction(trans, rc->extent_root);
2166 btrfs_block_rsv_release(rc->extent_root,
2167 rc->block_rsv, num_bytes);
2168 goto again;
2169 }
2170 }
2171
2172 rc->merge_reloc_tree = 1;
2173
2174 while (!list_empty(&rc->reloc_roots)) {
2175 reloc_root = list_entry(rc->reloc_roots.next,
2176 struct btrfs_root, root_list);
2177 list_del_init(&reloc_root->root_list);
2178
2179 root = read_fs_root(reloc_root->fs_info,
2180 reloc_root->root_key.offset);
2181 BUG_ON(IS_ERR(root));
2182 BUG_ON(root->reloc_root != reloc_root);
2183
2184 /*
2185 * set reference count to 1, so btrfs_recover_relocation
2186 * knows it should resumes merging
2187 */
2188 if (!err)
2189 btrfs_set_root_refs(&reloc_root->root_item, 1);
2190 btrfs_update_reloc_root(trans, root);
2191
2192 list_add(&reloc_root->root_list, &reloc_roots);
2193 }
2194
2195 list_splice(&reloc_roots, &rc->reloc_roots);
2196
2197 if (!err)
2198 btrfs_commit_transaction(trans, rc->extent_root);
2199 else
2200 btrfs_end_transaction(trans, rc->extent_root);
2201 return err;
2202 }
2203
2204 static noinline_for_stack
2205 int merge_reloc_roots(struct reloc_control *rc)
2206 {
2207 struct btrfs_root *root;
2208 struct btrfs_root *reloc_root;
2209 LIST_HEAD(reloc_roots);
2210 int found = 0;
2211 int ret;
2212 again:
2213 root = rc->extent_root;
2214 mutex_lock(&root->fs_info->trans_mutex);
2215 list_splice_init(&rc->reloc_roots, &reloc_roots);
2216 mutex_unlock(&root->fs_info->trans_mutex);
2217
2218 while (!list_empty(&reloc_roots)) {
2219 found = 1;
2220 reloc_root = list_entry(reloc_roots.next,
2221 struct btrfs_root, root_list);
2222
2223 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2224 root = read_fs_root(reloc_root->fs_info,
2225 reloc_root->root_key.offset);
2226 BUG_ON(IS_ERR(root));
2227 BUG_ON(root->reloc_root != reloc_root);
2228
2229 ret = merge_reloc_root(rc, root);
2230 BUG_ON(ret);
2231 } else {
2232 list_del_init(&reloc_root->root_list);
2233 }
2234 btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0);
2235 }
2236
2237 if (found) {
2238 found = 0;
2239 goto again;
2240 }
2241 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2242 return 0;
2243 }
2244
2245 static void free_block_list(struct rb_root *blocks)
2246 {
2247 struct tree_block *block;
2248 struct rb_node *rb_node;
2249 while ((rb_node = rb_first(blocks))) {
2250 block = rb_entry(rb_node, struct tree_block, rb_node);
2251 rb_erase(rb_node, blocks);
2252 kfree(block);
2253 }
2254 }
2255
2256 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2257 struct btrfs_root *reloc_root)
2258 {
2259 struct btrfs_root *root;
2260
2261 if (reloc_root->last_trans == trans->transid)
2262 return 0;
2263
2264 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2265 BUG_ON(IS_ERR(root));
2266 BUG_ON(root->reloc_root != reloc_root);
2267
2268 return btrfs_record_root_in_trans(trans, root);
2269 }
2270
2271 static noinline_for_stack
2272 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2273 struct reloc_control *rc,
2274 struct backref_node *node,
2275 struct backref_edge *edges[], int *nr)
2276 {
2277 struct backref_node *next;
2278 struct btrfs_root *root;
2279 int index = 0;
2280
2281 next = node;
2282 while (1) {
2283 cond_resched();
2284 next = walk_up_backref(next, edges, &index);
2285 root = next->root;
2286 BUG_ON(!root);
2287 BUG_ON(!root->ref_cows);
2288
2289 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2290 record_reloc_root_in_trans(trans, root);
2291 break;
2292 }
2293
2294 btrfs_record_root_in_trans(trans, root);
2295 root = root->reloc_root;
2296
2297 if (next->new_bytenr != root->node->start) {
2298 BUG_ON(next->new_bytenr);
2299 BUG_ON(!list_empty(&next->list));
2300 next->new_bytenr = root->node->start;
2301 next->root = root;
2302 list_add_tail(&next->list,
2303 &rc->backref_cache.changed);
2304 __mark_block_processed(rc, next);
2305 break;
2306 }
2307
2308 WARN_ON(1);
2309 root = NULL;
2310 next = walk_down_backref(edges, &index);
2311 if (!next || next->level <= node->level)
2312 break;
2313 }
2314 if (!root)
2315 return NULL;
2316
2317 *nr = index;
2318 next = node;
2319 /* setup backref node path for btrfs_reloc_cow_block */
2320 while (1) {
2321 rc->backref_cache.path[next->level] = next;
2322 if (--index < 0)
2323 break;
2324 next = edges[index]->node[UPPER];
2325 }
2326 return root;
2327 }
2328
2329 /*
2330 * select a tree root for relocation. return NULL if the block
2331 * is reference counted. we should use do_relocation() in this
2332 * case. return a tree root pointer if the block isn't reference
2333 * counted. return -ENOENT if the block is root of reloc tree.
2334 */
2335 static noinline_for_stack
2336 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2337 struct backref_node *node)
2338 {
2339 struct backref_node *next;
2340 struct btrfs_root *root;
2341 struct btrfs_root *fs_root = NULL;
2342 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2343 int index = 0;
2344
2345 next = node;
2346 while (1) {
2347 cond_resched();
2348 next = walk_up_backref(next, edges, &index);
2349 root = next->root;
2350 BUG_ON(!root);
2351
2352 /* no other choice for non-refernce counted tree */
2353 if (!root->ref_cows)
2354 return root;
2355
2356 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2357 fs_root = root;
2358
2359 if (next != node)
2360 return NULL;
2361
2362 next = walk_down_backref(edges, &index);
2363 if (!next || next->level <= node->level)
2364 break;
2365 }
2366
2367 if (!fs_root)
2368 return ERR_PTR(-ENOENT);
2369 return fs_root;
2370 }
2371
2372 static noinline_for_stack
2373 u64 calcu_metadata_size(struct reloc_control *rc,
2374 struct backref_node *node, int reserve)
2375 {
2376 struct backref_node *next = node;
2377 struct backref_edge *edge;
2378 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2379 u64 num_bytes = 0;
2380 int index = 0;
2381
2382 BUG_ON(reserve && node->processed);
2383
2384 while (next) {
2385 cond_resched();
2386 while (1) {
2387 if (next->processed && (reserve || next != node))
2388 break;
2389
2390 num_bytes += btrfs_level_size(rc->extent_root,
2391 next->level);
2392
2393 if (list_empty(&next->upper))
2394 break;
2395
2396 edge = list_entry(next->upper.next,
2397 struct backref_edge, list[LOWER]);
2398 edges[index++] = edge;
2399 next = edge->node[UPPER];
2400 }
2401 next = walk_down_backref(edges, &index);
2402 }
2403 return num_bytes;
2404 }
2405
2406 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2407 struct reloc_control *rc,
2408 struct backref_node *node)
2409 {
2410 struct btrfs_root *root = rc->extent_root;
2411 u64 num_bytes;
2412 int ret;
2413
2414 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2415
2416 trans->block_rsv = rc->block_rsv;
2417 ret = btrfs_block_rsv_add(trans, root, rc->block_rsv, num_bytes);
2418 if (ret) {
2419 if (ret == -EAGAIN)
2420 rc->commit_transaction = 1;
2421 return ret;
2422 }
2423
2424 return 0;
2425 }
2426
2427 static void release_metadata_space(struct reloc_control *rc,
2428 struct backref_node *node)
2429 {
2430 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2431 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2432 }
2433
2434 /*
2435 * relocate a block tree, and then update pointers in upper level
2436 * blocks that reference the block to point to the new location.
2437 *
2438 * if called by link_to_upper, the block has already been relocated.
2439 * in that case this function just updates pointers.
2440 */
2441 static int do_relocation(struct btrfs_trans_handle *trans,
2442 struct reloc_control *rc,
2443 struct backref_node *node,
2444 struct btrfs_key *key,
2445 struct btrfs_path *path, int lowest)
2446 {
2447 struct backref_node *upper;
2448 struct backref_edge *edge;
2449 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2450 struct btrfs_root *root;
2451 struct extent_buffer *eb;
2452 u32 blocksize;
2453 u64 bytenr;
2454 u64 generation;
2455 int nr;
2456 int slot;
2457 int ret;
2458 int err = 0;
2459
2460 BUG_ON(lowest && node->eb);
2461
2462 path->lowest_level = node->level + 1;
2463 rc->backref_cache.path[node->level] = node;
2464 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2465 cond_resched();
2466
2467 upper = edge->node[UPPER];
2468 root = select_reloc_root(trans, rc, upper, edges, &nr);
2469 BUG_ON(!root);
2470
2471 if (upper->eb && !upper->locked) {
2472 if (!lowest) {
2473 ret = btrfs_bin_search(upper->eb, key,
2474 upper->level, &slot);
2475 BUG_ON(ret);
2476 bytenr = btrfs_node_blockptr(upper->eb, slot);
2477 if (node->eb->start == bytenr)
2478 goto next;
2479 }
2480 drop_node_buffer(upper);
2481 }
2482
2483 if (!upper->eb) {
2484 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2485 if (ret < 0) {
2486 err = ret;
2487 break;
2488 }
2489 BUG_ON(ret > 0);
2490
2491 if (!upper->eb) {
2492 upper->eb = path->nodes[upper->level];
2493 path->nodes[upper->level] = NULL;
2494 } else {
2495 BUG_ON(upper->eb != path->nodes[upper->level]);
2496 }
2497
2498 upper->locked = 1;
2499 path->locks[upper->level] = 0;
2500
2501 slot = path->slots[upper->level];
2502 btrfs_release_path(NULL, path);
2503 } else {
2504 ret = btrfs_bin_search(upper->eb, key, upper->level,
2505 &slot);
2506 BUG_ON(ret);
2507 }
2508
2509 bytenr = btrfs_node_blockptr(upper->eb, slot);
2510 if (lowest) {
2511 BUG_ON(bytenr != node->bytenr);
2512 } else {
2513 if (node->eb->start == bytenr)
2514 goto next;
2515 }
2516
2517 blocksize = btrfs_level_size(root, node->level);
2518 generation = btrfs_node_ptr_generation(upper->eb, slot);
2519 eb = read_tree_block(root, bytenr, blocksize, generation);
2520 if (!eb) {
2521 err = -EIO;
2522 goto next;
2523 }
2524 btrfs_tree_lock(eb);
2525 btrfs_set_lock_blocking(eb);
2526
2527 if (!node->eb) {
2528 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2529 slot, &eb);
2530 btrfs_tree_unlock(eb);
2531 free_extent_buffer(eb);
2532 if (ret < 0) {
2533 err = ret;
2534 goto next;
2535 }
2536 BUG_ON(node->eb != eb);
2537 } else {
2538 btrfs_set_node_blockptr(upper->eb, slot,
2539 node->eb->start);
2540 btrfs_set_node_ptr_generation(upper->eb, slot,
2541 trans->transid);
2542 btrfs_mark_buffer_dirty(upper->eb);
2543
2544 ret = btrfs_inc_extent_ref(trans, root,
2545 node->eb->start, blocksize,
2546 upper->eb->start,
2547 btrfs_header_owner(upper->eb),
2548 node->level, 0);
2549 BUG_ON(ret);
2550
2551 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2552 BUG_ON(ret);
2553 }
2554 next:
2555 if (!upper->pending)
2556 drop_node_buffer(upper);
2557 else
2558 unlock_node_buffer(upper);
2559 if (err)
2560 break;
2561 }
2562
2563 if (!err && node->pending) {
2564 drop_node_buffer(node);
2565 list_move_tail(&node->list, &rc->backref_cache.changed);
2566 node->pending = 0;
2567 }
2568
2569 path->lowest_level = 0;
2570 BUG_ON(err == -ENOSPC);
2571 return err;
2572 }
2573
2574 static int link_to_upper(struct btrfs_trans_handle *trans,
2575 struct reloc_control *rc,
2576 struct backref_node *node,
2577 struct btrfs_path *path)
2578 {
2579 struct btrfs_key key;
2580
2581 btrfs_node_key_to_cpu(node->eb, &key, 0);
2582 return do_relocation(trans, rc, node, &key, path, 0);
2583 }
2584
2585 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2586 struct reloc_control *rc,
2587 struct btrfs_path *path, int err)
2588 {
2589 LIST_HEAD(list);
2590 struct backref_cache *cache = &rc->backref_cache;
2591 struct backref_node *node;
2592 int level;
2593 int ret;
2594
2595 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2596 while (!list_empty(&cache->pending[level])) {
2597 node = list_entry(cache->pending[level].next,
2598 struct backref_node, list);
2599 list_move_tail(&node->list, &list);
2600 BUG_ON(!node->pending);
2601
2602 if (!err) {
2603 ret = link_to_upper(trans, rc, node, path);
2604 if (ret < 0)
2605 err = ret;
2606 }
2607 }
2608 list_splice_init(&list, &cache->pending[level]);
2609 }
2610 return err;
2611 }
2612
2613 static void mark_block_processed(struct reloc_control *rc,
2614 u64 bytenr, u32 blocksize)
2615 {
2616 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2617 EXTENT_DIRTY, GFP_NOFS);
2618 }
2619
2620 static void __mark_block_processed(struct reloc_control *rc,
2621 struct backref_node *node)
2622 {
2623 u32 blocksize;
2624 if (node->level == 0 ||
2625 in_block_group(node->bytenr, rc->block_group)) {
2626 blocksize = btrfs_level_size(rc->extent_root, node->level);
2627 mark_block_processed(rc, node->bytenr, blocksize);
2628 }
2629 node->processed = 1;
2630 }
2631
2632 /*
2633 * mark a block and all blocks directly/indirectly reference the block
2634 * as processed.
2635 */
2636 static void update_processed_blocks(struct reloc_control *rc,
2637 struct backref_node *node)
2638 {
2639 struct backref_node *next = node;
2640 struct backref_edge *edge;
2641 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2642 int index = 0;
2643
2644 while (next) {
2645 cond_resched();
2646 while (1) {
2647 if (next->processed)
2648 break;
2649
2650 __mark_block_processed(rc, next);
2651
2652 if (list_empty(&next->upper))
2653 break;
2654
2655 edge = list_entry(next->upper.next,
2656 struct backref_edge, list[LOWER]);
2657 edges[index++] = edge;
2658 next = edge->node[UPPER];
2659 }
2660 next = walk_down_backref(edges, &index);
2661 }
2662 }
2663
2664 static int tree_block_processed(u64 bytenr, u32 blocksize,
2665 struct reloc_control *rc)
2666 {
2667 if (test_range_bit(&rc->processed_blocks, bytenr,
2668 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2669 return 1;
2670 return 0;
2671 }
2672
2673 static int get_tree_block_key(struct reloc_control *rc,
2674 struct tree_block *block)
2675 {
2676 struct extent_buffer *eb;
2677
2678 BUG_ON(block->key_ready);
2679 eb = read_tree_block(rc->extent_root, block->bytenr,
2680 block->key.objectid, block->key.offset);
2681 BUG_ON(!eb);
2682 WARN_ON(btrfs_header_level(eb) != block->level);
2683 if (block->level == 0)
2684 btrfs_item_key_to_cpu(eb, &block->key, 0);
2685 else
2686 btrfs_node_key_to_cpu(eb, &block->key, 0);
2687 free_extent_buffer(eb);
2688 block->key_ready = 1;
2689 return 0;
2690 }
2691
2692 static int reada_tree_block(struct reloc_control *rc,
2693 struct tree_block *block)
2694 {
2695 BUG_ON(block->key_ready);
2696 readahead_tree_block(rc->extent_root, block->bytenr,
2697 block->key.objectid, block->key.offset);
2698 return 0;
2699 }
2700
2701 /*
2702 * helper function to relocate a tree block
2703 */
2704 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2705 struct reloc_control *rc,
2706 struct backref_node *node,
2707 struct btrfs_key *key,
2708 struct btrfs_path *path)
2709 {
2710 struct btrfs_root *root;
2711 int release = 0;
2712 int ret = 0;
2713
2714 if (!node)
2715 return 0;
2716
2717 BUG_ON(node->processed);
2718 root = select_one_root(trans, node);
2719 if (root == ERR_PTR(-ENOENT)) {
2720 update_processed_blocks(rc, node);
2721 goto out;
2722 }
2723
2724 if (!root || root->ref_cows) {
2725 ret = reserve_metadata_space(trans, rc, node);
2726 if (ret)
2727 goto out;
2728 release = 1;
2729 }
2730
2731 if (root) {
2732 if (root->ref_cows) {
2733 BUG_ON(node->new_bytenr);
2734 BUG_ON(!list_empty(&node->list));
2735 btrfs_record_root_in_trans(trans, root);
2736 root = root->reloc_root;
2737 node->new_bytenr = root->node->start;
2738 node->root = root;
2739 list_add_tail(&node->list, &rc->backref_cache.changed);
2740 } else {
2741 path->lowest_level = node->level;
2742 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2743 btrfs_release_path(root, path);
2744 if (ret > 0)
2745 ret = 0;
2746 }
2747 if (!ret)
2748 update_processed_blocks(rc, node);
2749 } else {
2750 ret = do_relocation(trans, rc, node, key, path, 1);
2751 }
2752 out:
2753 if (ret || node->level == 0 || node->cowonly) {
2754 if (release)
2755 release_metadata_space(rc, node);
2756 remove_backref_node(&rc->backref_cache, node);
2757 }
2758 return ret;
2759 }
2760
2761 /*
2762 * relocate a list of blocks
2763 */
2764 static noinline_for_stack
2765 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2766 struct reloc_control *rc, struct rb_root *blocks)
2767 {
2768 struct backref_node *node;
2769 struct btrfs_path *path;
2770 struct tree_block *block;
2771 struct rb_node *rb_node;
2772 int ret;
2773 int err = 0;
2774
2775 path = btrfs_alloc_path();
2776 if (!path)
2777 return -ENOMEM;
2778
2779 rb_node = rb_first(blocks);
2780 while (rb_node) {
2781 block = rb_entry(rb_node, struct tree_block, rb_node);
2782 if (!block->key_ready)
2783 reada_tree_block(rc, block);
2784 rb_node = rb_next(rb_node);
2785 }
2786
2787 rb_node = rb_first(blocks);
2788 while (rb_node) {
2789 block = rb_entry(rb_node, struct tree_block, rb_node);
2790 if (!block->key_ready)
2791 get_tree_block_key(rc, block);
2792 rb_node = rb_next(rb_node);
2793 }
2794
2795 rb_node = rb_first(blocks);
2796 while (rb_node) {
2797 block = rb_entry(rb_node, struct tree_block, rb_node);
2798
2799 node = build_backref_tree(rc, &block->key,
2800 block->level, block->bytenr);
2801 if (IS_ERR(node)) {
2802 err = PTR_ERR(node);
2803 goto out;
2804 }
2805
2806 ret = relocate_tree_block(trans, rc, node, &block->key,
2807 path);
2808 if (ret < 0) {
2809 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2810 err = ret;
2811 goto out;
2812 }
2813 rb_node = rb_next(rb_node);
2814 }
2815 out:
2816 free_block_list(blocks);
2817 err = finish_pending_nodes(trans, rc, path, err);
2818
2819 btrfs_free_path(path);
2820 return err;
2821 }
2822
2823 static noinline_for_stack
2824 int prealloc_file_extent_cluster(struct inode *inode,
2825 struct file_extent_cluster *cluster)
2826 {
2827 u64 alloc_hint = 0;
2828 u64 start;
2829 u64 end;
2830 u64 offset = BTRFS_I(inode)->index_cnt;
2831 u64 num_bytes;
2832 int nr = 0;
2833 int ret = 0;
2834
2835 BUG_ON(cluster->start != cluster->boundary[0]);
2836 mutex_lock(&inode->i_mutex);
2837
2838 ret = btrfs_check_data_free_space(inode, cluster->end +
2839 1 - cluster->start);
2840 if (ret)
2841 goto out;
2842
2843 while (nr < cluster->nr) {
2844 start = cluster->boundary[nr] - offset;
2845 if (nr + 1 < cluster->nr)
2846 end = cluster->boundary[nr + 1] - 1 - offset;
2847 else
2848 end = cluster->end - offset;
2849
2850 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2851 num_bytes = end + 1 - start;
2852 ret = btrfs_prealloc_file_range(inode, 0, start,
2853 num_bytes, num_bytes,
2854 end + 1, &alloc_hint);
2855 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2856 if (ret)
2857 break;
2858 nr++;
2859 }
2860 btrfs_free_reserved_data_space(inode, cluster->end +
2861 1 - cluster->start);
2862 out:
2863 mutex_unlock(&inode->i_mutex);
2864 return ret;
2865 }
2866
2867 static noinline_for_stack
2868 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
2869 u64 block_start)
2870 {
2871 struct btrfs_root *root = BTRFS_I(inode)->root;
2872 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2873 struct extent_map *em;
2874 int ret = 0;
2875
2876 em = alloc_extent_map(GFP_NOFS);
2877 if (!em)
2878 return -ENOMEM;
2879
2880 em->start = start;
2881 em->len = end + 1 - start;
2882 em->block_len = em->len;
2883 em->block_start = block_start;
2884 em->bdev = root->fs_info->fs_devices->latest_bdev;
2885 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2886
2887 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2888 while (1) {
2889 write_lock(&em_tree->lock);
2890 ret = add_extent_mapping(em_tree, em);
2891 write_unlock(&em_tree->lock);
2892 if (ret != -EEXIST) {
2893 free_extent_map(em);
2894 break;
2895 }
2896 btrfs_drop_extent_cache(inode, start, end, 0);
2897 }
2898 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2899 return ret;
2900 }
2901
2902 static int relocate_file_extent_cluster(struct inode *inode,
2903 struct file_extent_cluster *cluster)
2904 {
2905 u64 page_start;
2906 u64 page_end;
2907 u64 offset = BTRFS_I(inode)->index_cnt;
2908 unsigned long index;
2909 unsigned long last_index;
2910 struct page *page;
2911 struct file_ra_state *ra;
2912 int nr = 0;
2913 int ret = 0;
2914
2915 if (!cluster->nr)
2916 return 0;
2917
2918 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2919 if (!ra)
2920 return -ENOMEM;
2921
2922 ret = prealloc_file_extent_cluster(inode, cluster);
2923 if (ret)
2924 goto out;
2925
2926 file_ra_state_init(ra, inode->i_mapping);
2927
2928 ret = setup_extent_mapping(inode, cluster->start - offset,
2929 cluster->end - offset, cluster->start);
2930 if (ret)
2931 goto out;
2932
2933 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
2934 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
2935 while (index <= last_index) {
2936 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
2937 if (ret)
2938 goto out;
2939
2940 page = find_lock_page(inode->i_mapping, index);
2941 if (!page) {
2942 page_cache_sync_readahead(inode->i_mapping,
2943 ra, NULL, index,
2944 last_index + 1 - index);
2945 page = grab_cache_page(inode->i_mapping, index);
2946 if (!page) {
2947 btrfs_delalloc_release_metadata(inode,
2948 PAGE_CACHE_SIZE);
2949 ret = -ENOMEM;
2950 goto out;
2951 }
2952 }
2953
2954 if (PageReadahead(page)) {
2955 page_cache_async_readahead(inode->i_mapping,
2956 ra, NULL, page, index,
2957 last_index + 1 - index);
2958 }
2959
2960 if (!PageUptodate(page)) {
2961 btrfs_readpage(NULL, page);
2962 lock_page(page);
2963 if (!PageUptodate(page)) {
2964 unlock_page(page);
2965 page_cache_release(page);
2966 btrfs_delalloc_release_metadata(inode,
2967 PAGE_CACHE_SIZE);
2968 ret = -EIO;
2969 goto out;
2970 }
2971 }
2972
2973 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2974 page_end = page_start + PAGE_CACHE_SIZE - 1;
2975
2976 lock_extent(&BTRFS_I(inode)->io_tree,
2977 page_start, page_end, GFP_NOFS);
2978
2979 set_page_extent_mapped(page);
2980
2981 if (nr < cluster->nr &&
2982 page_start + offset == cluster->boundary[nr]) {
2983 set_extent_bits(&BTRFS_I(inode)->io_tree,
2984 page_start, page_end,
2985 EXTENT_BOUNDARY, GFP_NOFS);
2986 nr++;
2987 }
2988
2989 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
2990 set_page_dirty(page);
2991
2992 unlock_extent(&BTRFS_I(inode)->io_tree,
2993 page_start, page_end, GFP_NOFS);
2994 unlock_page(page);
2995 page_cache_release(page);
2996
2997 index++;
2998 balance_dirty_pages_ratelimited(inode->i_mapping);
2999 btrfs_throttle(BTRFS_I(inode)->root);
3000 }
3001 WARN_ON(nr != cluster->nr);
3002 out:
3003 kfree(ra);
3004 return ret;
3005 }
3006
3007 static noinline_for_stack
3008 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3009 struct file_extent_cluster *cluster)
3010 {
3011 int ret;
3012
3013 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3014 ret = relocate_file_extent_cluster(inode, cluster);
3015 if (ret)
3016 return ret;
3017 cluster->nr = 0;
3018 }
3019
3020 if (!cluster->nr)
3021 cluster->start = extent_key->objectid;
3022 else
3023 BUG_ON(cluster->nr >= MAX_EXTENTS);
3024 cluster->end = extent_key->objectid + extent_key->offset - 1;
3025 cluster->boundary[cluster->nr] = extent_key->objectid;
3026 cluster->nr++;
3027
3028 if (cluster->nr >= MAX_EXTENTS) {
3029 ret = relocate_file_extent_cluster(inode, cluster);
3030 if (ret)
3031 return ret;
3032 cluster->nr = 0;
3033 }
3034 return 0;
3035 }
3036
3037 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3038 static int get_ref_objectid_v0(struct reloc_control *rc,
3039 struct btrfs_path *path,
3040 struct btrfs_key *extent_key,
3041 u64 *ref_objectid, int *path_change)
3042 {
3043 struct btrfs_key key;
3044 struct extent_buffer *leaf;
3045 struct btrfs_extent_ref_v0 *ref0;
3046 int ret;
3047 int slot;
3048
3049 leaf = path->nodes[0];
3050 slot = path->slots[0];
3051 while (1) {
3052 if (slot >= btrfs_header_nritems(leaf)) {
3053 ret = btrfs_next_leaf(rc->extent_root, path);
3054 if (ret < 0)
3055 return ret;
3056 BUG_ON(ret > 0);
3057 leaf = path->nodes[0];
3058 slot = path->slots[0];
3059 if (path_change)
3060 *path_change = 1;
3061 }
3062 btrfs_item_key_to_cpu(leaf, &key, slot);
3063 if (key.objectid != extent_key->objectid)
3064 return -ENOENT;
3065
3066 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3067 slot++;
3068 continue;
3069 }
3070 ref0 = btrfs_item_ptr(leaf, slot,
3071 struct btrfs_extent_ref_v0);
3072 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3073 break;
3074 }
3075 return 0;
3076 }
3077 #endif
3078
3079 /*
3080 * helper to add a tree block to the list.
3081 * the major work is getting the generation and level of the block
3082 */
3083 static int add_tree_block(struct reloc_control *rc,
3084 struct btrfs_key *extent_key,
3085 struct btrfs_path *path,
3086 struct rb_root *blocks)
3087 {
3088 struct extent_buffer *eb;
3089 struct btrfs_extent_item *ei;
3090 struct btrfs_tree_block_info *bi;
3091 struct tree_block *block;
3092 struct rb_node *rb_node;
3093 u32 item_size;
3094 int level = -1;
3095 int generation;
3096
3097 eb = path->nodes[0];
3098 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3099
3100 if (item_size >= sizeof(*ei) + sizeof(*bi)) {
3101 ei = btrfs_item_ptr(eb, path->slots[0],
3102 struct btrfs_extent_item);
3103 bi = (struct btrfs_tree_block_info *)(ei + 1);
3104 generation = btrfs_extent_generation(eb, ei);
3105 level = btrfs_tree_block_level(eb, bi);
3106 } else {
3107 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3108 u64 ref_owner;
3109 int ret;
3110
3111 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3112 ret = get_ref_objectid_v0(rc, path, extent_key,
3113 &ref_owner, NULL);
3114 if (ret < 0)
3115 return ret;
3116 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3117 level = (int)ref_owner;
3118 /* FIXME: get real generation */
3119 generation = 0;
3120 #else
3121 BUG();
3122 #endif
3123 }
3124
3125 btrfs_release_path(rc->extent_root, path);
3126
3127 BUG_ON(level == -1);
3128
3129 block = kmalloc(sizeof(*block), GFP_NOFS);
3130 if (!block)
3131 return -ENOMEM;
3132
3133 block->bytenr = extent_key->objectid;
3134 block->key.objectid = extent_key->offset;
3135 block->key.offset = generation;
3136 block->level = level;
3137 block->key_ready = 0;
3138
3139 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3140 BUG_ON(rb_node);
3141
3142 return 0;
3143 }
3144
3145 /*
3146 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3147 */
3148 static int __add_tree_block(struct reloc_control *rc,
3149 u64 bytenr, u32 blocksize,
3150 struct rb_root *blocks)
3151 {
3152 struct btrfs_path *path;
3153 struct btrfs_key key;
3154 int ret;
3155
3156 if (tree_block_processed(bytenr, blocksize, rc))
3157 return 0;
3158
3159 if (tree_search(blocks, bytenr))
3160 return 0;
3161
3162 path = btrfs_alloc_path();
3163 if (!path)
3164 return -ENOMEM;
3165
3166 key.objectid = bytenr;
3167 key.type = BTRFS_EXTENT_ITEM_KEY;
3168 key.offset = blocksize;
3169
3170 path->search_commit_root = 1;
3171 path->skip_locking = 1;
3172 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3173 if (ret < 0)
3174 goto out;
3175 BUG_ON(ret);
3176
3177 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3178 ret = add_tree_block(rc, &key, path, blocks);
3179 out:
3180 btrfs_free_path(path);
3181 return ret;
3182 }
3183
3184 /*
3185 * helper to check if the block use full backrefs for pointers in it
3186 */
3187 static int block_use_full_backref(struct reloc_control *rc,
3188 struct extent_buffer *eb)
3189 {
3190 u64 flags;
3191 int ret;
3192
3193 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3194 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3195 return 1;
3196
3197 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3198 eb->start, eb->len, NULL, &flags);
3199 BUG_ON(ret);
3200
3201 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3202 ret = 1;
3203 else
3204 ret = 0;
3205 return ret;
3206 }
3207
3208 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3209 struct inode *inode, u64 ino)
3210 {
3211 struct btrfs_key key;
3212 struct btrfs_path *path;
3213 struct btrfs_root *root = fs_info->tree_root;
3214 struct btrfs_trans_handle *trans;
3215 unsigned long nr;
3216 int ret = 0;
3217
3218 if (inode)
3219 goto truncate;
3220
3221 key.objectid = ino;
3222 key.type = BTRFS_INODE_ITEM_KEY;
3223 key.offset = 0;
3224
3225 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3226 if (!inode || IS_ERR(inode) || is_bad_inode(inode)) {
3227 if (inode && !IS_ERR(inode))
3228 iput(inode);
3229 return -ENOENT;
3230 }
3231
3232 truncate:
3233 path = btrfs_alloc_path();
3234 if (!path) {
3235 ret = -ENOMEM;
3236 goto out;
3237 }
3238
3239 trans = btrfs_join_transaction(root, 0);
3240 if (IS_ERR(trans)) {
3241 btrfs_free_path(path);
3242 ret = PTR_ERR(trans);
3243 goto out;
3244 }
3245
3246 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
3247
3248 btrfs_free_path(path);
3249 nr = trans->blocks_used;
3250 btrfs_end_transaction(trans, root);
3251 btrfs_btree_balance_dirty(root, nr);
3252 out:
3253 iput(inode);
3254 return ret;
3255 }
3256
3257 /*
3258 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3259 * this function scans fs tree to find blocks reference the data extent
3260 */
3261 static int find_data_references(struct reloc_control *rc,
3262 struct btrfs_key *extent_key,
3263 struct extent_buffer *leaf,
3264 struct btrfs_extent_data_ref *ref,
3265 struct rb_root *blocks)
3266 {
3267 struct btrfs_path *path;
3268 struct tree_block *block;
3269 struct btrfs_root *root;
3270 struct btrfs_file_extent_item *fi;
3271 struct rb_node *rb_node;
3272 struct btrfs_key key;
3273 u64 ref_root;
3274 u64 ref_objectid;
3275 u64 ref_offset;
3276 u32 ref_count;
3277 u32 nritems;
3278 int err = 0;
3279 int added = 0;
3280 int counted;
3281 int ret;
3282
3283 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3284 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3285 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3286 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3287
3288 /*
3289 * This is an extent belonging to the free space cache, lets just delete
3290 * it and redo the search.
3291 */
3292 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3293 ret = delete_block_group_cache(rc->extent_root->fs_info,
3294 NULL, ref_objectid);
3295 if (ret != -ENOENT)
3296 return ret;
3297 ret = 0;
3298 }
3299
3300 path = btrfs_alloc_path();
3301 if (!path)
3302 return -ENOMEM;
3303
3304 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3305 if (IS_ERR(root)) {
3306 err = PTR_ERR(root);
3307 goto out;
3308 }
3309
3310 key.objectid = ref_objectid;
3311 key.offset = ref_offset;
3312 key.type = BTRFS_EXTENT_DATA_KEY;
3313
3314 path->search_commit_root = 1;
3315 path->skip_locking = 1;
3316 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3317 if (ret < 0) {
3318 err = ret;
3319 goto out;
3320 }
3321
3322 leaf = path->nodes[0];
3323 nritems = btrfs_header_nritems(leaf);
3324 /*
3325 * the references in tree blocks that use full backrefs
3326 * are not counted in
3327 */
3328 if (block_use_full_backref(rc, leaf))
3329 counted = 0;
3330 else
3331 counted = 1;
3332 rb_node = tree_search(blocks, leaf->start);
3333 if (rb_node) {
3334 if (counted)
3335 added = 1;
3336 else
3337 path->slots[0] = nritems;
3338 }
3339
3340 while (ref_count > 0) {
3341 while (path->slots[0] >= nritems) {
3342 ret = btrfs_next_leaf(root, path);
3343 if (ret < 0) {
3344 err = ret;
3345 goto out;
3346 }
3347 if (ret > 0) {
3348 WARN_ON(1);
3349 goto out;
3350 }
3351
3352 leaf = path->nodes[0];
3353 nritems = btrfs_header_nritems(leaf);
3354 added = 0;
3355
3356 if (block_use_full_backref(rc, leaf))
3357 counted = 0;
3358 else
3359 counted = 1;
3360 rb_node = tree_search(blocks, leaf->start);
3361 if (rb_node) {
3362 if (counted)
3363 added = 1;
3364 else
3365 path->slots[0] = nritems;
3366 }
3367 }
3368
3369 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3370 if (key.objectid != ref_objectid ||
3371 key.type != BTRFS_EXTENT_DATA_KEY) {
3372 WARN_ON(1);
3373 break;
3374 }
3375
3376 fi = btrfs_item_ptr(leaf, path->slots[0],
3377 struct btrfs_file_extent_item);
3378
3379 if (btrfs_file_extent_type(leaf, fi) ==
3380 BTRFS_FILE_EXTENT_INLINE)
3381 goto next;
3382
3383 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3384 extent_key->objectid)
3385 goto next;
3386
3387 key.offset -= btrfs_file_extent_offset(leaf, fi);
3388 if (key.offset != ref_offset)
3389 goto next;
3390
3391 if (counted)
3392 ref_count--;
3393 if (added)
3394 goto next;
3395
3396 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3397 block = kmalloc(sizeof(*block), GFP_NOFS);
3398 if (!block) {
3399 err = -ENOMEM;
3400 break;
3401 }
3402 block->bytenr = leaf->start;
3403 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3404 block->level = 0;
3405 block->key_ready = 1;
3406 rb_node = tree_insert(blocks, block->bytenr,
3407 &block->rb_node);
3408 BUG_ON(rb_node);
3409 }
3410 if (counted)
3411 added = 1;
3412 else
3413 path->slots[0] = nritems;
3414 next:
3415 path->slots[0]++;
3416
3417 }
3418 out:
3419 btrfs_free_path(path);
3420 return err;
3421 }
3422
3423 /*
3424 * hepler to find all tree blocks that reference a given data extent
3425 */
3426 static noinline_for_stack
3427 int add_data_references(struct reloc_control *rc,
3428 struct btrfs_key *extent_key,
3429 struct btrfs_path *path,
3430 struct rb_root *blocks)
3431 {
3432 struct btrfs_key key;
3433 struct extent_buffer *eb;
3434 struct btrfs_extent_data_ref *dref;
3435 struct btrfs_extent_inline_ref *iref;
3436 unsigned long ptr;
3437 unsigned long end;
3438 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3439 int ret;
3440 int err = 0;
3441
3442 eb = path->nodes[0];
3443 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3444 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3445 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3446 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3447 ptr = end;
3448 else
3449 #endif
3450 ptr += sizeof(struct btrfs_extent_item);
3451
3452 while (ptr < end) {
3453 iref = (struct btrfs_extent_inline_ref *)ptr;
3454 key.type = btrfs_extent_inline_ref_type(eb, iref);
3455 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3456 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3457 ret = __add_tree_block(rc, key.offset, blocksize,
3458 blocks);
3459 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3460 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3461 ret = find_data_references(rc, extent_key,
3462 eb, dref, blocks);
3463 } else {
3464 BUG();
3465 }
3466 ptr += btrfs_extent_inline_ref_size(key.type);
3467 }
3468 WARN_ON(ptr > end);
3469
3470 while (1) {
3471 cond_resched();
3472 eb = path->nodes[0];
3473 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3474 ret = btrfs_next_leaf(rc->extent_root, path);
3475 if (ret < 0) {
3476 err = ret;
3477 break;
3478 }
3479 if (ret > 0)
3480 break;
3481 eb = path->nodes[0];
3482 }
3483
3484 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3485 if (key.objectid != extent_key->objectid)
3486 break;
3487
3488 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3489 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3490 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3491 #else
3492 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3493 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3494 #endif
3495 ret = __add_tree_block(rc, key.offset, blocksize,
3496 blocks);
3497 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3498 dref = btrfs_item_ptr(eb, path->slots[0],
3499 struct btrfs_extent_data_ref);
3500 ret = find_data_references(rc, extent_key,
3501 eb, dref, blocks);
3502 } else {
3503 ret = 0;
3504 }
3505 if (ret) {
3506 err = ret;
3507 break;
3508 }
3509 path->slots[0]++;
3510 }
3511 btrfs_release_path(rc->extent_root, path);
3512 if (err)
3513 free_block_list(blocks);
3514 return err;
3515 }
3516
3517 /*
3518 * hepler to find next unprocessed extent
3519 */
3520 static noinline_for_stack
3521 int find_next_extent(struct btrfs_trans_handle *trans,
3522 struct reloc_control *rc, struct btrfs_path *path,
3523 struct btrfs_key *extent_key)
3524 {
3525 struct btrfs_key key;
3526 struct extent_buffer *leaf;
3527 u64 start, end, last;
3528 int ret;
3529
3530 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3531 while (1) {
3532 cond_resched();
3533 if (rc->search_start >= last) {
3534 ret = 1;
3535 break;
3536 }
3537
3538 key.objectid = rc->search_start;
3539 key.type = BTRFS_EXTENT_ITEM_KEY;
3540 key.offset = 0;
3541
3542 path->search_commit_root = 1;
3543 path->skip_locking = 1;
3544 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3545 0, 0);
3546 if (ret < 0)
3547 break;
3548 next:
3549 leaf = path->nodes[0];
3550 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3551 ret = btrfs_next_leaf(rc->extent_root, path);
3552 if (ret != 0)
3553 break;
3554 leaf = path->nodes[0];
3555 }
3556
3557 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3558 if (key.objectid >= last) {
3559 ret = 1;
3560 break;
3561 }
3562
3563 if (key.type != BTRFS_EXTENT_ITEM_KEY ||
3564 key.objectid + key.offset <= rc->search_start) {
3565 path->slots[0]++;
3566 goto next;
3567 }
3568
3569 ret = find_first_extent_bit(&rc->processed_blocks,
3570 key.objectid, &start, &end,
3571 EXTENT_DIRTY);
3572
3573 if (ret == 0 && start <= key.objectid) {
3574 btrfs_release_path(rc->extent_root, path);
3575 rc->search_start = end + 1;
3576 } else {
3577 rc->search_start = key.objectid + key.offset;
3578 memcpy(extent_key, &key, sizeof(key));
3579 return 0;
3580 }
3581 }
3582 btrfs_release_path(rc->extent_root, path);
3583 return ret;
3584 }
3585
3586 static void set_reloc_control(struct reloc_control *rc)
3587 {
3588 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3589 mutex_lock(&fs_info->trans_mutex);
3590 fs_info->reloc_ctl = rc;
3591 mutex_unlock(&fs_info->trans_mutex);
3592 }
3593
3594 static void unset_reloc_control(struct reloc_control *rc)
3595 {
3596 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3597 mutex_lock(&fs_info->trans_mutex);
3598 fs_info->reloc_ctl = NULL;
3599 mutex_unlock(&fs_info->trans_mutex);
3600 }
3601
3602 static int check_extent_flags(u64 flags)
3603 {
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_EXTENT_FLAG_TREE_BLOCK))
3609 return 1;
3610 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3611 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3612 return 1;
3613 return 0;
3614 }
3615
3616 static noinline_for_stack
3617 int prepare_to_relocate(struct reloc_control *rc)
3618 {
3619 struct btrfs_trans_handle *trans;
3620 int ret;
3621
3622 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root);
3623 if (!rc->block_rsv)
3624 return -ENOMEM;
3625
3626 /*
3627 * reserve some space for creating reloc trees.
3628 * btrfs_init_reloc_root will use them when there
3629 * is no reservation in transaction handle.
3630 */
3631 ret = btrfs_block_rsv_add(NULL, rc->extent_root, rc->block_rsv,
3632 rc->extent_root->nodesize * 256);
3633 if (ret)
3634 return ret;
3635
3636 rc->block_rsv->refill_used = 1;
3637 btrfs_add_durable_block_rsv(rc->extent_root->fs_info, rc->block_rsv);
3638
3639 memset(&rc->cluster, 0, sizeof(rc->cluster));
3640 rc->search_start = rc->block_group->key.objectid;
3641 rc->extents_found = 0;
3642 rc->nodes_relocated = 0;
3643 rc->merging_rsv_size = 0;
3644
3645 rc->create_reloc_tree = 1;
3646 set_reloc_control(rc);
3647
3648 trans = btrfs_join_transaction(rc->extent_root, 1);
3649 BUG_ON(IS_ERR(trans));
3650 btrfs_commit_transaction(trans, rc->extent_root);
3651 return 0;
3652 }
3653
3654 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3655 {
3656 struct rb_root blocks = RB_ROOT;
3657 struct btrfs_key key;
3658 struct btrfs_trans_handle *trans = NULL;
3659 struct btrfs_path *path;
3660 struct btrfs_extent_item *ei;
3661 unsigned long nr;
3662 u64 flags;
3663 u32 item_size;
3664 int ret;
3665 int err = 0;
3666 int progress = 0;
3667
3668 path = btrfs_alloc_path();
3669 if (!path)
3670 return -ENOMEM;
3671
3672 ret = prepare_to_relocate(rc);
3673 if (ret) {
3674 err = ret;
3675 goto out_free;
3676 }
3677
3678 while (1) {
3679 progress++;
3680 trans = btrfs_start_transaction(rc->extent_root, 0);
3681 BUG_ON(IS_ERR(trans));
3682 restart:
3683 if (update_backref_cache(trans, &rc->backref_cache)) {
3684 btrfs_end_transaction(trans, rc->extent_root);
3685 continue;
3686 }
3687
3688 ret = find_next_extent(trans, rc, path, &key);
3689 if (ret < 0)
3690 err = ret;
3691 if (ret != 0)
3692 break;
3693
3694 rc->extents_found++;
3695
3696 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3697 struct btrfs_extent_item);
3698 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3699 if (item_size >= sizeof(*ei)) {
3700 flags = btrfs_extent_flags(path->nodes[0], ei);
3701 ret = check_extent_flags(flags);
3702 BUG_ON(ret);
3703
3704 } else {
3705 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3706 u64 ref_owner;
3707 int path_change = 0;
3708
3709 BUG_ON(item_size !=
3710 sizeof(struct btrfs_extent_item_v0));
3711 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3712 &path_change);
3713 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3714 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3715 else
3716 flags = BTRFS_EXTENT_FLAG_DATA;
3717
3718 if (path_change) {
3719 btrfs_release_path(rc->extent_root, path);
3720
3721 path->search_commit_root = 1;
3722 path->skip_locking = 1;
3723 ret = btrfs_search_slot(NULL, rc->extent_root,
3724 &key, path, 0, 0);
3725 if (ret < 0) {
3726 err = ret;
3727 break;
3728 }
3729 BUG_ON(ret > 0);
3730 }
3731 #else
3732 BUG();
3733 #endif
3734 }
3735
3736 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3737 ret = add_tree_block(rc, &key, path, &blocks);
3738 } else if (rc->stage == UPDATE_DATA_PTRS &&
3739 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3740 ret = add_data_references(rc, &key, path, &blocks);
3741 } else {
3742 btrfs_release_path(rc->extent_root, path);
3743 ret = 0;
3744 }
3745 if (ret < 0) {
3746 err = ret;
3747 break;
3748 }
3749
3750 if (!RB_EMPTY_ROOT(&blocks)) {
3751 ret = relocate_tree_blocks(trans, rc, &blocks);
3752 if (ret < 0) {
3753 if (ret != -EAGAIN) {
3754 err = ret;
3755 break;
3756 }
3757 rc->extents_found--;
3758 rc->search_start = key.objectid;
3759 }
3760 }
3761
3762 ret = btrfs_block_rsv_check(trans, rc->extent_root,
3763 rc->block_rsv, 0, 5);
3764 if (ret < 0) {
3765 if (ret != -EAGAIN) {
3766 err = ret;
3767 WARN_ON(1);
3768 break;
3769 }
3770 rc->commit_transaction = 1;
3771 }
3772
3773 if (rc->commit_transaction) {
3774 rc->commit_transaction = 0;
3775 ret = btrfs_commit_transaction(trans, rc->extent_root);
3776 BUG_ON(ret);
3777 } else {
3778 nr = trans->blocks_used;
3779 btrfs_end_transaction_throttle(trans, rc->extent_root);
3780 btrfs_btree_balance_dirty(rc->extent_root, nr);
3781 }
3782 trans = NULL;
3783
3784 if (rc->stage == MOVE_DATA_EXTENTS &&
3785 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3786 rc->found_file_extent = 1;
3787 ret = relocate_data_extent(rc->data_inode,
3788 &key, &rc->cluster);
3789 if (ret < 0) {
3790 err = ret;
3791 break;
3792 }
3793 }
3794 }
3795 if (trans && progress && err == -ENOSPC) {
3796 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
3797 rc->block_group->flags);
3798 if (ret == 0) {
3799 err = 0;
3800 progress = 0;
3801 goto restart;
3802 }
3803 }
3804
3805 btrfs_release_path(rc->extent_root, path);
3806 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3807 GFP_NOFS);
3808
3809 if (trans) {
3810 nr = trans->blocks_used;
3811 btrfs_end_transaction_throttle(trans, rc->extent_root);
3812 btrfs_btree_balance_dirty(rc->extent_root, nr);
3813 }
3814
3815 if (!err) {
3816 ret = relocate_file_extent_cluster(rc->data_inode,
3817 &rc->cluster);
3818 if (ret < 0)
3819 err = ret;
3820 }
3821
3822 rc->create_reloc_tree = 0;
3823 set_reloc_control(rc);
3824
3825 backref_cache_cleanup(&rc->backref_cache);
3826 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3827
3828 err = prepare_to_merge(rc, err);
3829
3830 merge_reloc_roots(rc);
3831
3832 rc->merge_reloc_tree = 0;
3833 unset_reloc_control(rc);
3834 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3835
3836 /* get rid of pinned extents */
3837 trans = btrfs_join_transaction(rc->extent_root, 1);
3838 if (IS_ERR(trans))
3839 err = PTR_ERR(trans);
3840 else
3841 btrfs_commit_transaction(trans, rc->extent_root);
3842 out_free:
3843 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
3844 btrfs_free_path(path);
3845 return err;
3846 }
3847
3848 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3849 struct btrfs_root *root, u64 objectid)
3850 {
3851 struct btrfs_path *path;
3852 struct btrfs_inode_item *item;
3853 struct extent_buffer *leaf;
3854 int ret;
3855
3856 path = btrfs_alloc_path();
3857 if (!path)
3858 return -ENOMEM;
3859
3860 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3861 if (ret)
3862 goto out;
3863
3864 leaf = path->nodes[0];
3865 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3866 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
3867 btrfs_set_inode_generation(leaf, item, 1);
3868 btrfs_set_inode_size(leaf, item, 0);
3869 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3870 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3871 BTRFS_INODE_PREALLOC);
3872 btrfs_mark_buffer_dirty(leaf);
3873 btrfs_release_path(root, path);
3874 out:
3875 btrfs_free_path(path);
3876 return ret;
3877 }
3878
3879 /*
3880 * helper to create inode for data relocation.
3881 * the inode is in data relocation tree and its link count is 0
3882 */
3883 static noinline_for_stack
3884 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3885 struct btrfs_block_group_cache *group)
3886 {
3887 struct inode *inode = NULL;
3888 struct btrfs_trans_handle *trans;
3889 struct btrfs_root *root;
3890 struct btrfs_key key;
3891 unsigned long nr;
3892 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
3893 int err = 0;
3894
3895 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
3896 if (IS_ERR(root))
3897 return ERR_CAST(root);
3898
3899 trans = btrfs_start_transaction(root, 6);
3900 if (IS_ERR(trans))
3901 return ERR_CAST(trans);
3902
3903 err = btrfs_find_free_objectid(root, &objectid);
3904 if (err)
3905 goto out;
3906
3907 err = __insert_orphan_inode(trans, root, objectid);
3908 BUG_ON(err);
3909
3910 key.objectid = objectid;
3911 key.type = BTRFS_INODE_ITEM_KEY;
3912 key.offset = 0;
3913 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
3914 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
3915 BTRFS_I(inode)->index_cnt = group->key.objectid;
3916
3917 err = btrfs_orphan_add(trans, inode);
3918 out:
3919 nr = trans->blocks_used;
3920 btrfs_end_transaction(trans, root);
3921 btrfs_btree_balance_dirty(root, nr);
3922 if (err) {
3923 if (inode)
3924 iput(inode);
3925 inode = ERR_PTR(err);
3926 }
3927 return inode;
3928 }
3929
3930 static struct reloc_control *alloc_reloc_control(void)
3931 {
3932 struct reloc_control *rc;
3933
3934 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3935 if (!rc)
3936 return NULL;
3937
3938 INIT_LIST_HEAD(&rc->reloc_roots);
3939 backref_cache_init(&rc->backref_cache);
3940 mapping_tree_init(&rc->reloc_root_tree);
3941 extent_io_tree_init(&rc->processed_blocks, NULL, GFP_NOFS);
3942 return rc;
3943 }
3944
3945 /*
3946 * function to relocate all extents in a block group.
3947 */
3948 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
3949 {
3950 struct btrfs_fs_info *fs_info = extent_root->fs_info;
3951 struct reloc_control *rc;
3952 struct inode *inode;
3953 struct btrfs_path *path;
3954 int ret;
3955 int rw = 0;
3956 int err = 0;
3957
3958 rc = alloc_reloc_control();
3959 if (!rc)
3960 return -ENOMEM;
3961
3962 rc->extent_root = extent_root;
3963
3964 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
3965 BUG_ON(!rc->block_group);
3966
3967 if (!rc->block_group->ro) {
3968 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
3969 if (ret) {
3970 err = ret;
3971 goto out;
3972 }
3973 rw = 1;
3974 }
3975
3976 path = btrfs_alloc_path();
3977 if (!path) {
3978 err = -ENOMEM;
3979 goto out;
3980 }
3981
3982 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
3983 path);
3984 btrfs_free_path(path);
3985
3986 if (!IS_ERR(inode))
3987 ret = delete_block_group_cache(fs_info, inode, 0);
3988 else
3989 ret = PTR_ERR(inode);
3990
3991 if (ret && ret != -ENOENT) {
3992 err = ret;
3993 goto out;
3994 }
3995
3996 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
3997 if (IS_ERR(rc->data_inode)) {
3998 err = PTR_ERR(rc->data_inode);
3999 rc->data_inode = NULL;
4000 goto out;
4001 }
4002
4003 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
4004 (unsigned long long)rc->block_group->key.objectid,
4005 (unsigned long long)rc->block_group->flags);
4006
4007 btrfs_start_delalloc_inodes(fs_info->tree_root, 0);
4008 btrfs_wait_ordered_extents(fs_info->tree_root, 0, 0);
4009
4010 while (1) {
4011 mutex_lock(&fs_info->cleaner_mutex);
4012
4013 btrfs_clean_old_snapshots(fs_info->tree_root);
4014 ret = relocate_block_group(rc);
4015
4016 mutex_unlock(&fs_info->cleaner_mutex);
4017 if (ret < 0) {
4018 err = ret;
4019 goto out;
4020 }
4021
4022 if (rc->extents_found == 0)
4023 break;
4024
4025 printk(KERN_INFO "btrfs: found %llu extents\n",
4026 (unsigned long long)rc->extents_found);
4027
4028 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4029 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
4030 invalidate_mapping_pages(rc->data_inode->i_mapping,
4031 0, -1);
4032 rc->stage = UPDATE_DATA_PTRS;
4033 }
4034 }
4035
4036 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
4037 rc->block_group->key.objectid,
4038 rc->block_group->key.objectid +
4039 rc->block_group->key.offset - 1);
4040
4041 WARN_ON(rc->block_group->pinned > 0);
4042 WARN_ON(rc->block_group->reserved > 0);
4043 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4044 out:
4045 if (err && rw)
4046 btrfs_set_block_group_rw(extent_root, rc->block_group);
4047 iput(rc->data_inode);
4048 btrfs_put_block_group(rc->block_group);
4049 kfree(rc);
4050 return err;
4051 }
4052
4053 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4054 {
4055 struct btrfs_trans_handle *trans;
4056 int ret;
4057
4058 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4059 BUG_ON(IS_ERR(trans));
4060
4061 memset(&root->root_item.drop_progress, 0,
4062 sizeof(root->root_item.drop_progress));
4063 root->root_item.drop_level = 0;
4064 btrfs_set_root_refs(&root->root_item, 0);
4065 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4066 &root->root_key, &root->root_item);
4067 BUG_ON(ret);
4068
4069 ret = btrfs_end_transaction(trans, root->fs_info->tree_root);
4070 BUG_ON(ret);
4071 return 0;
4072 }
4073
4074 /*
4075 * recover relocation interrupted by system crash.
4076 *
4077 * this function resumes merging reloc trees with corresponding fs trees.
4078 * this is important for keeping the sharing of tree blocks
4079 */
4080 int btrfs_recover_relocation(struct btrfs_root *root)
4081 {
4082 LIST_HEAD(reloc_roots);
4083 struct btrfs_key key;
4084 struct btrfs_root *fs_root;
4085 struct btrfs_root *reloc_root;
4086 struct btrfs_path *path;
4087 struct extent_buffer *leaf;
4088 struct reloc_control *rc = NULL;
4089 struct btrfs_trans_handle *trans;
4090 int ret;
4091 int err = 0;
4092
4093 path = btrfs_alloc_path();
4094 if (!path)
4095 return -ENOMEM;
4096
4097 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4098 key.type = BTRFS_ROOT_ITEM_KEY;
4099 key.offset = (u64)-1;
4100
4101 while (1) {
4102 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4103 path, 0, 0);
4104 if (ret < 0) {
4105 err = ret;
4106 goto out;
4107 }
4108 if (ret > 0) {
4109 if (path->slots[0] == 0)
4110 break;
4111 path->slots[0]--;
4112 }
4113 leaf = path->nodes[0];
4114 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4115 btrfs_release_path(root->fs_info->tree_root, path);
4116
4117 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4118 key.type != BTRFS_ROOT_ITEM_KEY)
4119 break;
4120
4121 reloc_root = btrfs_read_fs_root_no_radix(root, &key);
4122 if (IS_ERR(reloc_root)) {
4123 err = PTR_ERR(reloc_root);
4124 goto out;
4125 }
4126
4127 list_add(&reloc_root->root_list, &reloc_roots);
4128
4129 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4130 fs_root = read_fs_root(root->fs_info,
4131 reloc_root->root_key.offset);
4132 if (IS_ERR(fs_root)) {
4133 ret = PTR_ERR(fs_root);
4134 if (ret != -ENOENT) {
4135 err = ret;
4136 goto out;
4137 }
4138 mark_garbage_root(reloc_root);
4139 }
4140 }
4141
4142 if (key.offset == 0)
4143 break;
4144
4145 key.offset--;
4146 }
4147 btrfs_release_path(root->fs_info->tree_root, path);
4148
4149 if (list_empty(&reloc_roots))
4150 goto out;
4151
4152 rc = alloc_reloc_control();
4153 if (!rc) {
4154 err = -ENOMEM;
4155 goto out;
4156 }
4157
4158 rc->extent_root = root->fs_info->extent_root;
4159
4160 set_reloc_control(rc);
4161
4162 trans = btrfs_join_transaction(rc->extent_root, 1);
4163 if (IS_ERR(trans)) {
4164 unset_reloc_control(rc);
4165 err = PTR_ERR(trans);
4166 goto out_free;
4167 }
4168
4169 rc->merge_reloc_tree = 1;
4170
4171 while (!list_empty(&reloc_roots)) {
4172 reloc_root = list_entry(reloc_roots.next,
4173 struct btrfs_root, root_list);
4174 list_del(&reloc_root->root_list);
4175
4176 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4177 list_add_tail(&reloc_root->root_list,
4178 &rc->reloc_roots);
4179 continue;
4180 }
4181
4182 fs_root = read_fs_root(root->fs_info,
4183 reloc_root->root_key.offset);
4184 BUG_ON(IS_ERR(fs_root));
4185
4186 __add_reloc_root(reloc_root);
4187 fs_root->reloc_root = reloc_root;
4188 }
4189
4190 btrfs_commit_transaction(trans, rc->extent_root);
4191
4192 merge_reloc_roots(rc);
4193
4194 unset_reloc_control(rc);
4195
4196 trans = btrfs_join_transaction(rc->extent_root, 1);
4197 if (IS_ERR(trans))
4198 err = PTR_ERR(trans);
4199 else
4200 btrfs_commit_transaction(trans, rc->extent_root);
4201 out_free:
4202 kfree(rc);
4203 out:
4204 while (!list_empty(&reloc_roots)) {
4205 reloc_root = list_entry(reloc_roots.next,
4206 struct btrfs_root, root_list);
4207 list_del(&reloc_root->root_list);
4208 free_extent_buffer(reloc_root->node);
4209 free_extent_buffer(reloc_root->commit_root);
4210 kfree(reloc_root);
4211 }
4212 btrfs_free_path(path);
4213
4214 if (err == 0) {
4215 /* cleanup orphan inode in data relocation tree */
4216 fs_root = read_fs_root(root->fs_info,
4217 BTRFS_DATA_RELOC_TREE_OBJECTID);
4218 if (IS_ERR(fs_root))
4219 err = PTR_ERR(fs_root);
4220 else
4221 err = btrfs_orphan_cleanup(fs_root);
4222 }
4223 return err;
4224 }
4225
4226 /*
4227 * helper to add ordered checksum for data relocation.
4228 *
4229 * cloning checksum properly handles the nodatasum extents.
4230 * it also saves CPU time to re-calculate the checksum.
4231 */
4232 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4233 {
4234 struct btrfs_ordered_sum *sums;
4235 struct btrfs_sector_sum *sector_sum;
4236 struct btrfs_ordered_extent *ordered;
4237 struct btrfs_root *root = BTRFS_I(inode)->root;
4238 size_t offset;
4239 int ret;
4240 u64 disk_bytenr;
4241 LIST_HEAD(list);
4242
4243 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4244 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4245
4246 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4247 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4248 disk_bytenr + len - 1, &list);
4249
4250 while (!list_empty(&list)) {
4251 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4252 list_del_init(&sums->list);
4253
4254 sector_sum = sums->sums;
4255 sums->bytenr = ordered->start;
4256
4257 offset = 0;
4258 while (offset < sums->len) {
4259 sector_sum->bytenr += ordered->start - disk_bytenr;
4260 sector_sum++;
4261 offset += root->sectorsize;
4262 }
4263
4264 btrfs_add_ordered_sum(inode, ordered, sums);
4265 }
4266 btrfs_put_ordered_extent(ordered);
4267 return ret;
4268 }
4269
4270 void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4271 struct btrfs_root *root, struct extent_buffer *buf,
4272 struct extent_buffer *cow)
4273 {
4274 struct reloc_control *rc;
4275 struct backref_node *node;
4276 int first_cow = 0;
4277 int level;
4278 int ret;
4279
4280 rc = root->fs_info->reloc_ctl;
4281 if (!rc)
4282 return;
4283
4284 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4285 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4286
4287 level = btrfs_header_level(buf);
4288 if (btrfs_header_generation(buf) <=
4289 btrfs_root_last_snapshot(&root->root_item))
4290 first_cow = 1;
4291
4292 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4293 rc->create_reloc_tree) {
4294 WARN_ON(!first_cow && level == 0);
4295
4296 node = rc->backref_cache.path[level];
4297 BUG_ON(node->bytenr != buf->start &&
4298 node->new_bytenr != buf->start);
4299
4300 drop_node_buffer(node);
4301 extent_buffer_get(cow);
4302 node->eb = cow;
4303 node->new_bytenr = cow->start;
4304
4305 if (!node->pending) {
4306 list_move_tail(&node->list,
4307 &rc->backref_cache.pending[level]);
4308 node->pending = 1;
4309 }
4310
4311 if (first_cow)
4312 __mark_block_processed(rc, node);
4313
4314 if (first_cow && level > 0)
4315 rc->nodes_relocated += buf->len;
4316 }
4317
4318 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) {
4319 ret = replace_file_extents(trans, rc, root, cow);
4320 BUG_ON(ret);
4321 }
4322 }
4323
4324 /*
4325 * called before creating snapshot. it calculates metadata reservation
4326 * requried for relocating tree blocks in the snapshot
4327 */
4328 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4329 struct btrfs_pending_snapshot *pending,
4330 u64 *bytes_to_reserve)
4331 {
4332 struct btrfs_root *root;
4333 struct reloc_control *rc;
4334
4335 root = pending->root;
4336 if (!root->reloc_root)
4337 return;
4338
4339 rc = root->fs_info->reloc_ctl;
4340 if (!rc->merge_reloc_tree)
4341 return;
4342
4343 root = root->reloc_root;
4344 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4345 /*
4346 * relocation is in the stage of merging trees. the space
4347 * used by merging a reloc tree is twice the size of
4348 * relocated tree nodes in the worst case. half for cowing
4349 * the reloc tree, half for cowing the fs tree. the space
4350 * used by cowing the reloc tree will be freed after the
4351 * tree is dropped. if we create snapshot, cowing the fs
4352 * tree may use more space than it frees. so we need
4353 * reserve extra space.
4354 */
4355 *bytes_to_reserve += rc->nodes_relocated;
4356 }
4357
4358 /*
4359 * called after snapshot is created. migrate block reservation
4360 * and create reloc root for the newly created snapshot
4361 */
4362 void btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4363 struct btrfs_pending_snapshot *pending)
4364 {
4365 struct btrfs_root *root = pending->root;
4366 struct btrfs_root *reloc_root;
4367 struct btrfs_root *new_root;
4368 struct reloc_control *rc;
4369 int ret;
4370
4371 if (!root->reloc_root)
4372 return;
4373
4374 rc = root->fs_info->reloc_ctl;
4375 rc->merging_rsv_size += rc->nodes_relocated;
4376
4377 if (rc->merge_reloc_tree) {
4378 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4379 rc->block_rsv,
4380 rc->nodes_relocated);
4381 BUG_ON(ret);
4382 }
4383
4384 new_root = pending->snap;
4385 reloc_root = create_reloc_root(trans, root->reloc_root,
4386 new_root->root_key.objectid);
4387
4388 __add_reloc_root(reloc_root);
4389 new_root->reloc_root = reloc_root;
4390
4391 if (rc->create_reloc_tree) {
4392 ret = clone_backref_node(trans, rc, root, reloc_root);
4393 BUG_ON(ret);
4394 }
4395 }
kernel source for telekom puls (alcatel/mediatek)