?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Merge branch 'for-2639-rc7/i2c-fixes' of git://git.fluff.org/bjdooks/linux
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / btrfs / relocation.c
blob31ade5802ae8a31f8ab48c5bdcbba0cebcddfe96
1 /*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33
34 /*
35 * backref_node, mapping_node and tree_block start with this
36 */
37 struct tree_entry {
38 struct rb_node rb_node;
39 u64 bytenr;
40 };
41
42 /*
43 * present a tree block in the backref cache
44 */
45 struct backref_node {
46 struct rb_node rb_node;
47 u64 bytenr;
48
49 u64 new_bytenr;
50 /* objectid of tree block owner, can be not uptodate */
51 u64 owner;
52 /* link to pending, changed or detached list */
53 struct list_head list;
54 /* list of upper level blocks reference this block */
55 struct list_head upper;
56 /* list of child blocks in the cache */
57 struct list_head lower;
58 /* NULL if this node is not tree root */
59 struct btrfs_root *root;
60 /* extent buffer got by COW the block */
61 struct extent_buffer *eb;
62 /* level of tree block */
63 unsigned int level:8;
64 /* is the block in non-reference counted tree */
65 unsigned int cowonly:1;
66 /* 1 if no child node in the cache */
67 unsigned int lowest:1;
68 /* is the extent buffer locked */
69 unsigned int locked:1;
70 /* has the block been processed */
71 unsigned int processed:1;
72 /* have backrefs of this block been checked */
73 unsigned int checked:1;
74 /*
75 * 1 if corresponding block has been cowed but some upper
76 * level block pointers may not point to the new location
77 */
78 unsigned int pending:1;
79 /*
80 * 1 if the backref node isn't connected to any other
81 * backref node.
82 */
83 unsigned int detached:1;
84 };
85
86 /*
87 * present a block pointer in the backref cache
88 */
89 struct backref_edge {
90 struct list_head list[2];
91 struct backref_node *node[2];
92 };
93
94 #define LOWER 0
95 #define UPPER 1
96
97 struct backref_cache {
98 /* red black tree of all backref nodes in the cache */
99 struct rb_root rb_root;
100 /* for passing backref nodes to btrfs_reloc_cow_block */
101 struct backref_node *path[BTRFS_MAX_LEVEL];
102 /*
103 * list of blocks that have been cowed but some block
104 * pointers in upper level blocks may not reflect the
105 * new location
106 */
107 struct list_head pending[BTRFS_MAX_LEVEL];
108 /* list of backref nodes with no child node */
109 struct list_head leaves;
110 /* list of blocks that have been cowed in current transaction */
111 struct list_head changed;
112 /* list of detached backref node. */
113 struct list_head detached;
114
115 u64 last_trans;
116
117 int nr_nodes;
118 int nr_edges;
119 };
120
121 /*
122 * map address of tree root to tree
123 */
124 struct mapping_node {
125 struct rb_node rb_node;
126 u64 bytenr;
127 void *data;
128 };
129
130 struct mapping_tree {
131 struct rb_root rb_root;
132 spinlock_t lock;
133 };
134
135 /*
136 * present a tree block to process
137 */
138 struct tree_block {
139 struct rb_node rb_node;
140 u64 bytenr;
141 struct btrfs_key key;
142 unsigned int level:8;
143 unsigned int key_ready:1;
144 };
145
146 #define MAX_EXTENTS 128
147
148 struct file_extent_cluster {
149 u64 start;
150 u64 end;
151 u64 boundary[MAX_EXTENTS];
152 unsigned int nr;
153 };
154
155 struct reloc_control {
156 /* block group to relocate */
157 struct btrfs_block_group_cache *block_group;
158 /* extent tree */
159 struct btrfs_root *extent_root;
160 /* inode for moving data */
161 struct inode *data_inode;
162
163 struct btrfs_block_rsv *block_rsv;
164
165 struct backref_cache backref_cache;
166
167 struct file_extent_cluster cluster;
168 /* tree blocks have been processed */
169 struct extent_io_tree processed_blocks;
170 /* map start of tree root to corresponding reloc tree */
171 struct mapping_tree reloc_root_tree;
172 /* list of reloc trees */
173 struct list_head reloc_roots;
174 /* size of metadata reservation for merging reloc trees */
175 u64 merging_rsv_size;
176 /* size of relocated tree nodes */
177 u64 nodes_relocated;
178
179 u64 search_start;
180 u64 extents_found;
181
182 unsigned int stage:8;
183 unsigned int create_reloc_tree:1;
184 unsigned int merge_reloc_tree:1;
185 unsigned int found_file_extent:1;
186 unsigned int commit_transaction:1;
187 };
188
189 /* stages of data relocation */
190 #define MOVE_DATA_EXTENTS 0
191 #define UPDATE_DATA_PTRS 1
192
193 static void remove_backref_node(struct backref_cache *cache,
194 struct backref_node *node);
195 static void __mark_block_processed(struct reloc_control *rc,
196 struct backref_node *node);
197
198 static void mapping_tree_init(struct mapping_tree *tree)
199 {
200 tree->rb_root = RB_ROOT;
201 spin_lock_init(&tree->lock);
202 }
203
204 static void backref_cache_init(struct backref_cache *cache)
205 {
206 int i;
207 cache->rb_root = RB_ROOT;
208 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
209 INIT_LIST_HEAD(&cache->pending[i]);
210 INIT_LIST_HEAD(&cache->changed);
211 INIT_LIST_HEAD(&cache->detached);
212 INIT_LIST_HEAD(&cache->leaves);
213 }
214
215 static void backref_cache_cleanup(struct backref_cache *cache)
216 {
217 struct backref_node *node;
218 int i;
219
220 while (!list_empty(&cache->detached)) {
221 node = list_entry(cache->detached.next,
222 struct backref_node, list);
223 remove_backref_node(cache, node);
224 }
225
226 while (!list_empty(&cache->leaves)) {
227 node = list_entry(cache->leaves.next,
228 struct backref_node, lower);
229 remove_backref_node(cache, node);
230 }
231
232 cache->last_trans = 0;
233
234 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
235 BUG_ON(!list_empty(&cache->pending[i]));
236 BUG_ON(!list_empty(&cache->changed));
237 BUG_ON(!list_empty(&cache->detached));
238 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
239 BUG_ON(cache->nr_nodes);
240 BUG_ON(cache->nr_edges);
241 }
242
243 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
244 {
245 struct backref_node *node;
246
247 node = kzalloc(sizeof(*node), GFP_NOFS);
248 if (node) {
249 INIT_LIST_HEAD(&node->list);
250 INIT_LIST_HEAD(&node->upper);
251 INIT_LIST_HEAD(&node->lower);
252 RB_CLEAR_NODE(&node->rb_node);
253 cache->nr_nodes++;
254 }
255 return node;
256 }
257
258 static void free_backref_node(struct backref_cache *cache,
259 struct backref_node *node)
260 {
261 if (node) {
262 cache->nr_nodes--;
263 kfree(node);
264 }
265 }
266
267 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
268 {
269 struct backref_edge *edge;
270
271 edge = kzalloc(sizeof(*edge), GFP_NOFS);
272 if (edge)
273 cache->nr_edges++;
274 return edge;
275 }
276
277 static void free_backref_edge(struct backref_cache *cache,
278 struct backref_edge *edge)
279 {
280 if (edge) {
281 cache->nr_edges--;
282 kfree(edge);
283 }
284 }
285
286 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
287 struct rb_node *node)
288 {
289 struct rb_node **p = &root->rb_node;
290 struct rb_node *parent = NULL;
291 struct tree_entry *entry;
292
293 while (*p) {
294 parent = *p;
295 entry = rb_entry(parent, struct tree_entry, rb_node);
296
297 if (bytenr < entry->bytenr)
298 p = &(*p)->rb_left;
299 else if (bytenr > entry->bytenr)
300 p = &(*p)->rb_right;
301 else
302 return parent;
303 }
304
305 rb_link_node(node, parent, p);
306 rb_insert_color(node, root);
307 return NULL;
308 }
309
310 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
311 {
312 struct rb_node *n = root->rb_node;
313 struct tree_entry *entry;
314
315 while (n) {
316 entry = rb_entry(n, struct tree_entry, rb_node);
317
318 if (bytenr < entry->bytenr)
319 n = n->rb_left;
320 else if (bytenr > entry->bytenr)
321 n = n->rb_right;
322 else
323 return n;
324 }
325 return NULL;
326 }
327
328 /*
329 * walk up backref nodes until reach node presents tree root
330 */
331 static struct backref_node *walk_up_backref(struct backref_node *node,
332 struct backref_edge *edges[],
333 int *index)
334 {
335 struct backref_edge *edge;
336 int idx = *index;
337
338 while (!list_empty(&node->upper)) {
339 edge = list_entry(node->upper.next,
340 struct backref_edge, list[LOWER]);
341 edges[idx++] = edge;
342 node = edge->node[UPPER];
343 }
344 BUG_ON(node->detached);
345 *index = idx;
346 return node;
347 }
348
349 /*
350 * walk down backref nodes to find start of next reference path
351 */
352 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
353 int *index)
354 {
355 struct backref_edge *edge;
356 struct backref_node *lower;
357 int idx = *index;
358
359 while (idx > 0) {
360 edge = edges[idx - 1];
361 lower = edge->node[LOWER];
362 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
363 idx--;
364 continue;
365 }
366 edge = list_entry(edge->list[LOWER].next,
367 struct backref_edge, list[LOWER]);
368 edges[idx - 1] = edge;
369 *index = idx;
370 return edge->node[UPPER];
371 }
372 *index = 0;
373 return NULL;
374 }
375
376 static void unlock_node_buffer(struct backref_node *node)
377 {
378 if (node->locked) {
379 btrfs_tree_unlock(node->eb);
380 node->locked = 0;
381 }
382 }
383
384 static void drop_node_buffer(struct backref_node *node)
385 {
386 if (node->eb) {
387 unlock_node_buffer(node);
388 free_extent_buffer(node->eb);
389 node->eb = NULL;
390 }
391 }
392
393 static void drop_backref_node(struct backref_cache *tree,
394 struct backref_node *node)
395 {
396 BUG_ON(!list_empty(&node->upper));
397
398 drop_node_buffer(node);
399 list_del(&node->list);
400 list_del(&node->lower);
401 if (!RB_EMPTY_NODE(&node->rb_node))
402 rb_erase(&node->rb_node, &tree->rb_root);
403 free_backref_node(tree, node);
404 }
405
406 /*
407 * remove a backref node from the backref cache
408 */
409 static void remove_backref_node(struct backref_cache *cache,
410 struct backref_node *node)
411 {
412 struct backref_node *upper;
413 struct backref_edge *edge;
414
415 if (!node)
416 return;
417
418 BUG_ON(!node->lowest && !node->detached);
419 while (!list_empty(&node->upper)) {
420 edge = list_entry(node->upper.next, struct backref_edge,
421 list[LOWER]);
422 upper = edge->node[UPPER];
423 list_del(&edge->list[LOWER]);
424 list_del(&edge->list[UPPER]);
425 free_backref_edge(cache, edge);
426
427 if (RB_EMPTY_NODE(&upper->rb_node)) {
428 BUG_ON(!list_empty(&node->upper));
429 drop_backref_node(cache, node);
430 node = upper;
431 node->lowest = 1;
432 continue;
433 }
434 /*
435 * add the node to leaf node list if no other
436 * child block cached.
437 */
438 if (list_empty(&upper->lower)) {
439 list_add_tail(&upper->lower, &cache->leaves);
440 upper->lowest = 1;
441 }
442 }
443
444 drop_backref_node(cache, node);
445 }
446
447 static void update_backref_node(struct backref_cache *cache,
448 struct backref_node *node, u64 bytenr)
449 {
450 struct rb_node *rb_node;
451 rb_erase(&node->rb_node, &cache->rb_root);
452 node->bytenr = bytenr;
453 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
454 BUG_ON(rb_node);
455 }
456
457 /*
458 * update backref cache after a transaction commit
459 */
460 static int update_backref_cache(struct btrfs_trans_handle *trans,
461 struct backref_cache *cache)
462 {
463 struct backref_node *node;
464 int level = 0;
465
466 if (cache->last_trans == 0) {
467 cache->last_trans = trans->transid;
468 return 0;
469 }
470
471 if (cache->last_trans == trans->transid)
472 return 0;
473
474 /*
475 * detached nodes are used to avoid unnecessary backref
476 * lookup. transaction commit changes the extent tree.
477 * so the detached nodes are no longer useful.
478 */
479 while (!list_empty(&cache->detached)) {
480 node = list_entry(cache->detached.next,
481 struct backref_node, list);
482 remove_backref_node(cache, node);
483 }
484
485 while (!list_empty(&cache->changed)) {
486 node = list_entry(cache->changed.next,
487 struct backref_node, list);
488 list_del_init(&node->list);
489 BUG_ON(node->pending);
490 update_backref_node(cache, node, node->new_bytenr);
491 }
492
493 /*
494 * some nodes can be left in the pending list if there were
495 * errors during processing the pending nodes.
496 */
497 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
498 list_for_each_entry(node, &cache->pending[level], list) {
499 BUG_ON(!node->pending);
500 if (node->bytenr == node->new_bytenr)
501 continue;
502 update_backref_node(cache, node, node->new_bytenr);
503 }
504 }
505
506 cache->last_trans = 0;
507 return 1;
508 }
509
510 static int should_ignore_root(struct btrfs_root *root)
511 {
512 struct btrfs_root *reloc_root;
513
514 if (!root->ref_cows)
515 return 0;
516
517 reloc_root = root->reloc_root;
518 if (!reloc_root)
519 return 0;
520
521 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
522 root->fs_info->running_transaction->transid - 1)
523 return 0;
524 /*
525 * if there is reloc tree and it was created in previous
526 * transaction backref lookup can find the reloc tree,
527 * so backref node for the fs tree root is useless for
528 * relocation.
529 */
530 return 1;
531 }
532
533 /*
534 * find reloc tree by address of tree root
535 */
536 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
537 u64 bytenr)
538 {
539 struct rb_node *rb_node;
540 struct mapping_node *node;
541 struct btrfs_root *root = NULL;
542
543 spin_lock(&rc->reloc_root_tree.lock);
544 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
545 if (rb_node) {
546 node = rb_entry(rb_node, struct mapping_node, rb_node);
547 root = (struct btrfs_root *)node->data;
548 }
549 spin_unlock(&rc->reloc_root_tree.lock);
550 return root;
551 }
552
553 static int is_cowonly_root(u64 root_objectid)
554 {
555 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
556 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
557 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
558 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
559 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
560 root_objectid == BTRFS_CSUM_TREE_OBJECTID)
561 return 1;
562 return 0;
563 }
564
565 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
566 u64 root_objectid)
567 {
568 struct btrfs_key key;
569
570 key.objectid = root_objectid;
571 key.type = BTRFS_ROOT_ITEM_KEY;
572 if (is_cowonly_root(root_objectid))
573 key.offset = 0;
574 else
575 key.offset = (u64)-1;
576
577 return btrfs_read_fs_root_no_name(fs_info, &key);
578 }
579
580 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
581 static noinline_for_stack
582 struct btrfs_root *find_tree_root(struct reloc_control *rc,
583 struct extent_buffer *leaf,
584 struct btrfs_extent_ref_v0 *ref0)
585 {
586 struct btrfs_root *root;
587 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
588 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
589
590 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
591
592 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
593 BUG_ON(IS_ERR(root));
594
595 if (root->ref_cows &&
596 generation != btrfs_root_generation(&root->root_item))
597 return NULL;
598
599 return root;
600 }
601 #endif
602
603 static noinline_for_stack
604 int find_inline_backref(struct extent_buffer *leaf, int slot,
605 unsigned long *ptr, unsigned long *end)
606 {
607 struct btrfs_extent_item *ei;
608 struct btrfs_tree_block_info *bi;
609 u32 item_size;
610
611 item_size = btrfs_item_size_nr(leaf, slot);
612 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
613 if (item_size < sizeof(*ei)) {
614 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
615 return 1;
616 }
617 #endif
618 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
619 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
620 BTRFS_EXTENT_FLAG_TREE_BLOCK));
621
622 if (item_size <= sizeof(*ei) + sizeof(*bi)) {
623 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
624 return 1;
625 }
626
627 bi = (struct btrfs_tree_block_info *)(ei + 1);
628 *ptr = (unsigned long)(bi + 1);
629 *end = (unsigned long)ei + item_size;
630 return 0;
631 }
632
633 /*
634 * build backref tree for a given tree block. root of the backref tree
635 * corresponds the tree block, leaves of the backref tree correspond
636 * roots of b-trees that reference the tree block.
637 *
638 * the basic idea of this function is check backrefs of a given block
639 * to find upper level blocks that refernece the block, and then check
640 * bakcrefs of these upper level blocks recursively. the recursion stop
641 * when tree root is reached or backrefs for the block is cached.
642 *
643 * NOTE: if we find backrefs for a block are cached, we know backrefs
644 * for all upper level blocks that directly/indirectly reference the
645 * block are also cached.
646 */
647 static noinline_for_stack
648 struct backref_node *build_backref_tree(struct reloc_control *rc,
649 struct btrfs_key *node_key,
650 int level, u64 bytenr)
651 {
652 struct backref_cache *cache = &rc->backref_cache;
653 struct btrfs_path *path1;
654 struct btrfs_path *path2;
655 struct extent_buffer *eb;
656 struct btrfs_root *root;
657 struct backref_node *cur;
658 struct backref_node *upper;
659 struct backref_node *lower;
660 struct backref_node *node = NULL;
661 struct backref_node *exist = NULL;
662 struct backref_edge *edge;
663 struct rb_node *rb_node;
664 struct btrfs_key key;
665 unsigned long end;
666 unsigned long ptr;
667 LIST_HEAD(list);
668 LIST_HEAD(useless);
669 int cowonly;
670 int ret;
671 int err = 0;
672
673 path1 = btrfs_alloc_path();
674 path2 = btrfs_alloc_path();
675 if (!path1 || !path2) {
676 err = -ENOMEM;
677 goto out;
678 }
679
680 node = alloc_backref_node(cache);
681 if (!node) {
682 err = -ENOMEM;
683 goto out;
684 }
685
686 node->bytenr = bytenr;
687 node->level = level;
688 node->lowest = 1;
689 cur = node;
690 again:
691 end = 0;
692 ptr = 0;
693 key.objectid = cur->bytenr;
694 key.type = BTRFS_EXTENT_ITEM_KEY;
695 key.offset = (u64)-1;
696
697 path1->search_commit_root = 1;
698 path1->skip_locking = 1;
699 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
700 0, 0);
701 if (ret < 0) {
702 err = ret;
703 goto out;
704 }
705 BUG_ON(!ret || !path1->slots[0]);
706
707 path1->slots[0]--;
708
709 WARN_ON(cur->checked);
710 if (!list_empty(&cur->upper)) {
711 /*
712 * the backref was added previously when processsing
713 * backref of type BTRFS_TREE_BLOCK_REF_KEY
714 */
715 BUG_ON(!list_is_singular(&cur->upper));
716 edge = list_entry(cur->upper.next, struct backref_edge,
717 list[LOWER]);
718 BUG_ON(!list_empty(&edge->list[UPPER]));
719 exist = edge->node[UPPER];
720 /*
721 * add the upper level block to pending list if we need
722 * check its backrefs
723 */
724 if (!exist->checked)
725 list_add_tail(&edge->list[UPPER], &list);
726 } else {
727 exist = NULL;
728 }
729
730 while (1) {
731 cond_resched();
732 eb = path1->nodes[0];
733
734 if (ptr >= end) {
735 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
736 ret = btrfs_next_leaf(rc->extent_root, path1);
737 if (ret < 0) {
738 err = ret;
739 goto out;
740 }
741 if (ret > 0)
742 break;
743 eb = path1->nodes[0];
744 }
745
746 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
747 if (key.objectid != cur->bytenr) {
748 WARN_ON(exist);
749 break;
750 }
751
752 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
753 ret = find_inline_backref(eb, path1->slots[0],
754 &ptr, &end);
755 if (ret)
756 goto next;
757 }
758 }
759
760 if (ptr < end) {
761 /* update key for inline back ref */
762 struct btrfs_extent_inline_ref *iref;
763 iref = (struct btrfs_extent_inline_ref *)ptr;
764 key.type = btrfs_extent_inline_ref_type(eb, iref);
765 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
766 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
767 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
768 }
769
770 if (exist &&
771 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
772 exist->owner == key.offset) ||
773 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
774 exist->bytenr == key.offset))) {
775 exist = NULL;
776 goto next;
777 }
778
779 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
780 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
781 key.type == BTRFS_EXTENT_REF_V0_KEY) {
782 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
783 struct btrfs_extent_ref_v0 *ref0;
784 ref0 = btrfs_item_ptr(eb, path1->slots[0],
785 struct btrfs_extent_ref_v0);
786 if (key.objectid == key.offset) {
787 root = find_tree_root(rc, eb, ref0);
788 if (root && !should_ignore_root(root))
789 cur->root = root;
790 else
791 list_add(&cur->list, &useless);
792 break;
793 }
794 if (is_cowonly_root(btrfs_ref_root_v0(eb,
795 ref0)))
796 cur->cowonly = 1;
797 }
798 #else
799 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
800 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
801 #endif
802 if (key.objectid == key.offset) {
803 /*
804 * only root blocks of reloc trees use
805 * backref of this type.
806 */
807 root = find_reloc_root(rc, cur->bytenr);
808 BUG_ON(!root);
809 cur->root = root;
810 break;
811 }
812
813 edge = alloc_backref_edge(cache);
814 if (!edge) {
815 err = -ENOMEM;
816 goto out;
817 }
818 rb_node = tree_search(&cache->rb_root, key.offset);
819 if (!rb_node) {
820 upper = alloc_backref_node(cache);
821 if (!upper) {
822 free_backref_edge(cache, edge);
823 err = -ENOMEM;
824 goto out;
825 }
826 upper->bytenr = key.offset;
827 upper->level = cur->level + 1;
828 /*
829 * backrefs for the upper level block isn't
830 * cached, add the block to pending list
831 */
832 list_add_tail(&edge->list[UPPER], &list);
833 } else {
834 upper = rb_entry(rb_node, struct backref_node,
835 rb_node);
836 BUG_ON(!upper->checked);
837 INIT_LIST_HEAD(&edge->list[UPPER]);
838 }
839 list_add_tail(&edge->list[LOWER], &cur->upper);
840 edge->node[LOWER] = cur;
841 edge->node[UPPER] = upper;
842
843 goto next;
844 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
845 goto next;
846 }
847
848 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
849 root = read_fs_root(rc->extent_root->fs_info, key.offset);
850 if (IS_ERR(root)) {
851 err = PTR_ERR(root);
852 goto out;
853 }
854
855 if (!root->ref_cows)
856 cur->cowonly = 1;
857
858 if (btrfs_root_level(&root->root_item) == cur->level) {
859 /* tree root */
860 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
861 cur->bytenr);
862 if (should_ignore_root(root))
863 list_add(&cur->list, &useless);
864 else
865 cur->root = root;
866 break;
867 }
868
869 level = cur->level + 1;
870
871 /*
872 * searching the tree to find upper level blocks
873 * reference the block.
874 */
875 path2->search_commit_root = 1;
876 path2->skip_locking = 1;
877 path2->lowest_level = level;
878 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
879 path2->lowest_level = 0;
880 if (ret < 0) {
881 err = ret;
882 goto out;
883 }
884 if (ret > 0 && path2->slots[level] > 0)
885 path2->slots[level]--;
886
887 eb = path2->nodes[level];
888 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
889 cur->bytenr);
890
891 lower = cur;
892 for (; level < BTRFS_MAX_LEVEL; level++) {
893 if (!path2->nodes[level]) {
894 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
895 lower->bytenr);
896 if (should_ignore_root(root))
897 list_add(&lower->list, &useless);
898 else
899 lower->root = root;
900 break;
901 }
902
903 edge = alloc_backref_edge(cache);
904 if (!edge) {
905 err = -ENOMEM;
906 goto out;
907 }
908
909 eb = path2->nodes[level];
910 rb_node = tree_search(&cache->rb_root, eb->start);
911 if (!rb_node) {
912 upper = alloc_backref_node(cache);
913 if (!upper) {
914 free_backref_edge(cache, edge);
915 err = -ENOMEM;
916 goto out;
917 }
918 upper->bytenr = eb->start;
919 upper->owner = btrfs_header_owner(eb);
920 upper->level = lower->level + 1;
921 if (!root->ref_cows)
922 upper->cowonly = 1;
923
924 /*
925 * if we know the block isn't shared
926 * we can void checking its backrefs.
927 */
928 if (btrfs_block_can_be_shared(root, eb))
929 upper->checked = 0;
930 else
931 upper->checked = 1;
932
933 /*
934 * add the block to pending list if we
935 * need check its backrefs. only block
936 * at 'cur->level + 1' is added to the
937 * tail of pending list. this guarantees
938 * we check backrefs from lower level
939 * blocks to upper level blocks.
940 */
941 if (!upper->checked &&
942 level == cur->level + 1) {
943 list_add_tail(&edge->list[UPPER],
944 &list);
945 } else
946 INIT_LIST_HEAD(&edge->list[UPPER]);
947 } else {
948 upper = rb_entry(rb_node, struct backref_node,
949 rb_node);
950 BUG_ON(!upper->checked);
951 INIT_LIST_HEAD(&edge->list[UPPER]);
952 if (!upper->owner)
953 upper->owner = btrfs_header_owner(eb);
954 }
955 list_add_tail(&edge->list[LOWER], &lower->upper);
956 edge->node[LOWER] = lower;
957 edge->node[UPPER] = upper;
958
959 if (rb_node)
960 break;
961 lower = upper;
962 upper = NULL;
963 }
964 btrfs_release_path(root, path2);
965 next:
966 if (ptr < end) {
967 ptr += btrfs_extent_inline_ref_size(key.type);
968 if (ptr >= end) {
969 WARN_ON(ptr > end);
970 ptr = 0;
971 end = 0;
972 }
973 }
974 if (ptr >= end)
975 path1->slots[0]++;
976 }
977 btrfs_release_path(rc->extent_root, path1);
978
979 cur->checked = 1;
980 WARN_ON(exist);
981
982 /* the pending list isn't empty, take the first block to process */
983 if (!list_empty(&list)) {
984 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
985 list_del_init(&edge->list[UPPER]);
986 cur = edge->node[UPPER];
987 goto again;
988 }
989
990 /*
991 * everything goes well, connect backref nodes and insert backref nodes
992 * into the cache.
993 */
994 BUG_ON(!node->checked);
995 cowonly = node->cowonly;
996 if (!cowonly) {
997 rb_node = tree_insert(&cache->rb_root, node->bytenr,
998 &node->rb_node);
999 BUG_ON(rb_node);
1000 list_add_tail(&node->lower, &cache->leaves);
1001 }
1002
1003 list_for_each_entry(edge, &node->upper, list[LOWER])
1004 list_add_tail(&edge->list[UPPER], &list);
1005
1006 while (!list_empty(&list)) {
1007 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1008 list_del_init(&edge->list[UPPER]);
1009 upper = edge->node[UPPER];
1010 if (upper->detached) {
1011 list_del(&edge->list[LOWER]);
1012 lower = edge->node[LOWER];
1013 free_backref_edge(cache, edge);
1014 if (list_empty(&lower->upper))
1015 list_add(&lower->list, &useless);
1016 continue;
1017 }
1018
1019 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1020 if (upper->lowest) {
1021 list_del_init(&upper->lower);
1022 upper->lowest = 0;
1023 }
1024
1025 list_add_tail(&edge->list[UPPER], &upper->lower);
1026 continue;
1027 }
1028
1029 BUG_ON(!upper->checked);
1030 BUG_ON(cowonly != upper->cowonly);
1031 if (!cowonly) {
1032 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1033 &upper->rb_node);
1034 BUG_ON(rb_node);
1035 }
1036
1037 list_add_tail(&edge->list[UPPER], &upper->lower);
1038
1039 list_for_each_entry(edge, &upper->upper, list[LOWER])
1040 list_add_tail(&edge->list[UPPER], &list);
1041 }
1042 /*
1043 * process useless backref nodes. backref nodes for tree leaves
1044 * are deleted from the cache. backref nodes for upper level
1045 * tree blocks are left in the cache to avoid unnecessary backref
1046 * lookup.
1047 */
1048 while (!list_empty(&useless)) {
1049 upper = list_entry(useless.next, struct backref_node, list);
1050 list_del_init(&upper->list);
1051 BUG_ON(!list_empty(&upper->upper));
1052 if (upper == node)
1053 node = NULL;
1054 if (upper->lowest) {
1055 list_del_init(&upper->lower);
1056 upper->lowest = 0;
1057 }
1058 while (!list_empty(&upper->lower)) {
1059 edge = list_entry(upper->lower.next,
1060 struct backref_edge, list[UPPER]);
1061 list_del(&edge->list[UPPER]);
1062 list_del(&edge->list[LOWER]);
1063 lower = edge->node[LOWER];
1064 free_backref_edge(cache, edge);
1065
1066 if (list_empty(&lower->upper))
1067 list_add(&lower->list, &useless);
1068 }
1069 __mark_block_processed(rc, upper);
1070 if (upper->level > 0) {
1071 list_add(&upper->list, &cache->detached);
1072 upper->detached = 1;
1073 } else {
1074 rb_erase(&upper->rb_node, &cache->rb_root);
1075 free_backref_node(cache, upper);
1076 }
1077 }
1078 out:
1079 btrfs_free_path(path1);
1080 btrfs_free_path(path2);
1081 if (err) {
1082 while (!list_empty(&useless)) {
1083 lower = list_entry(useless.next,
1084 struct backref_node, upper);
1085 list_del_init(&lower->upper);
1086 }
1087 upper = node;
1088 INIT_LIST_HEAD(&list);
1089 while (upper) {
1090 if (RB_EMPTY_NODE(&upper->rb_node)) {
1091 list_splice_tail(&upper->upper, &list);
1092 free_backref_node(cache, upper);
1093 }
1094
1095 if (list_empty(&list))
1096 break;
1097
1098 edge = list_entry(list.next, struct backref_edge,
1099 list[LOWER]);
1100 list_del(&edge->list[LOWER]);
1101 upper = edge->node[UPPER];
1102 free_backref_edge(cache, edge);
1103 }
1104 return ERR_PTR(err);
1105 }
1106 BUG_ON(node && node->detached);
1107 return node;
1108 }
1109
1110 /*
1111 * helper to add backref node for the newly created snapshot.
1112 * the backref node is created by cloning backref node that
1113 * corresponds to root of source tree
1114 */
1115 static int clone_backref_node(struct btrfs_trans_handle *trans,
1116 struct reloc_control *rc,
1117 struct btrfs_root *src,
1118 struct btrfs_root *dest)
1119 {
1120 struct btrfs_root *reloc_root = src->reloc_root;
1121 struct backref_cache *cache = &rc->backref_cache;
1122 struct backref_node *node = NULL;
1123 struct backref_node *new_node;
1124 struct backref_edge *edge;
1125 struct backref_edge *new_edge;
1126 struct rb_node *rb_node;
1127
1128 if (cache->last_trans > 0)
1129 update_backref_cache(trans, cache);
1130
1131 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1132 if (rb_node) {
1133 node = rb_entry(rb_node, struct backref_node, rb_node);
1134 if (node->detached)
1135 node = NULL;
1136 else
1137 BUG_ON(node->new_bytenr != reloc_root->node->start);
1138 }
1139
1140 if (!node) {
1141 rb_node = tree_search(&cache->rb_root,
1142 reloc_root->commit_root->start);
1143 if (rb_node) {
1144 node = rb_entry(rb_node, struct backref_node,
1145 rb_node);
1146 BUG_ON(node->detached);
1147 }
1148 }
1149
1150 if (!node)
1151 return 0;
1152
1153 new_node = alloc_backref_node(cache);
1154 if (!new_node)
1155 return -ENOMEM;
1156
1157 new_node->bytenr = dest->node->start;
1158 new_node->level = node->level;
1159 new_node->lowest = node->lowest;
1160 new_node->checked = 1;
1161 new_node->root = dest;
1162
1163 if (!node->lowest) {
1164 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1165 new_edge = alloc_backref_edge(cache);
1166 if (!new_edge)
1167 goto fail;
1168
1169 new_edge->node[UPPER] = new_node;
1170 new_edge->node[LOWER] = edge->node[LOWER];
1171 list_add_tail(&new_edge->list[UPPER],
1172 &new_node->lower);
1173 }
1174 }
1175
1176 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1177 &new_node->rb_node);
1178 BUG_ON(rb_node);
1179
1180 if (!new_node->lowest) {
1181 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1182 list_add_tail(&new_edge->list[LOWER],
1183 &new_edge->node[LOWER]->upper);
1184 }
1185 }
1186 return 0;
1187 fail:
1188 while (!list_empty(&new_node->lower)) {
1189 new_edge = list_entry(new_node->lower.next,
1190 struct backref_edge, list[UPPER]);
1191 list_del(&new_edge->list[UPPER]);
1192 free_backref_edge(cache, new_edge);
1193 }
1194 free_backref_node(cache, new_node);
1195 return -ENOMEM;
1196 }
1197
1198 /*
1199 * helper to add 'address of tree root -> reloc tree' mapping
1200 */
1201 static int __add_reloc_root(struct btrfs_root *root)
1202 {
1203 struct rb_node *rb_node;
1204 struct mapping_node *node;
1205 struct reloc_control *rc = root->fs_info->reloc_ctl;
1206
1207 node = kmalloc(sizeof(*node), GFP_NOFS);
1208 BUG_ON(!node);
1209
1210 node->bytenr = root->node->start;
1211 node->data = root;
1212
1213 spin_lock(&rc->reloc_root_tree.lock);
1214 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1215 node->bytenr, &node->rb_node);
1216 spin_unlock(&rc->reloc_root_tree.lock);
1217 BUG_ON(rb_node);
1218
1219 list_add_tail(&root->root_list, &rc->reloc_roots);
1220 return 0;
1221 }
1222
1223 /*
1224 * helper to update/delete the 'address of tree root -> reloc tree'
1225 * mapping
1226 */
1227 static int __update_reloc_root(struct btrfs_root *root, int del)
1228 {
1229 struct rb_node *rb_node;
1230 struct mapping_node *node = NULL;
1231 struct reloc_control *rc = root->fs_info->reloc_ctl;
1232
1233 spin_lock(&rc->reloc_root_tree.lock);
1234 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1235 root->commit_root->start);
1236 if (rb_node) {
1237 node = rb_entry(rb_node, struct mapping_node, rb_node);
1238 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1239 }
1240 spin_unlock(&rc->reloc_root_tree.lock);
1241
1242 BUG_ON((struct btrfs_root *)node->data != root);
1243
1244 if (!del) {
1245 spin_lock(&rc->reloc_root_tree.lock);
1246 node->bytenr = root->node->start;
1247 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1248 node->bytenr, &node->rb_node);
1249 spin_unlock(&rc->reloc_root_tree.lock);
1250 BUG_ON(rb_node);
1251 } else {
1252 list_del_init(&root->root_list);
1253 kfree(node);
1254 }
1255 return 0;
1256 }
1257
1258 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1259 struct btrfs_root *root, u64 objectid)
1260 {
1261 struct btrfs_root *reloc_root;
1262 struct extent_buffer *eb;
1263 struct btrfs_root_item *root_item;
1264 struct btrfs_key root_key;
1265 int ret;
1266
1267 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1268 BUG_ON(!root_item);
1269
1270 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1271 root_key.type = BTRFS_ROOT_ITEM_KEY;
1272 root_key.offset = objectid;
1273
1274 if (root->root_key.objectid == objectid) {
1275 /* called by btrfs_init_reloc_root */
1276 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1277 BTRFS_TREE_RELOC_OBJECTID);
1278 BUG_ON(ret);
1279
1280 btrfs_set_root_last_snapshot(&root->root_item,
1281 trans->transid - 1);
1282 } else {
1283 /*
1284 * called by btrfs_reloc_post_snapshot_hook.
1285 * the source tree is a reloc tree, all tree blocks
1286 * modified after it was created have RELOC flag
1287 * set in their headers. so it's OK to not update
1288 * the 'last_snapshot'.
1289 */
1290 ret = btrfs_copy_root(trans, root, root->node, &eb,
1291 BTRFS_TREE_RELOC_OBJECTID);
1292 BUG_ON(ret);
1293 }
1294
1295 memcpy(root_item, &root->root_item, sizeof(*root_item));
1296 btrfs_set_root_bytenr(root_item, eb->start);
1297 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1298 btrfs_set_root_generation(root_item, trans->transid);
1299
1300 if (root->root_key.objectid == objectid) {
1301 btrfs_set_root_refs(root_item, 0);
1302 memset(&root_item->drop_progress, 0,
1303 sizeof(struct btrfs_disk_key));
1304 root_item->drop_level = 0;
1305 }
1306
1307 btrfs_tree_unlock(eb);
1308 free_extent_buffer(eb);
1309
1310 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1311 &root_key, root_item);
1312 BUG_ON(ret);
1313 kfree(root_item);
1314
1315 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
1316 &root_key);
1317 BUG_ON(IS_ERR(reloc_root));
1318 reloc_root->last_trans = trans->transid;
1319 return reloc_root;
1320 }
1321
1322 /*
1323 * create reloc tree for a given fs tree. reloc tree is just a
1324 * snapshot of the fs tree with special root objectid.
1325 */
1326 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1327 struct btrfs_root *root)
1328 {
1329 struct btrfs_root *reloc_root;
1330 struct reloc_control *rc = root->fs_info->reloc_ctl;
1331 int clear_rsv = 0;
1332
1333 if (root->reloc_root) {
1334 reloc_root = root->reloc_root;
1335 reloc_root->last_trans = trans->transid;
1336 return 0;
1337 }
1338
1339 if (!rc || !rc->create_reloc_tree ||
1340 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1341 return 0;
1342
1343 if (!trans->block_rsv) {
1344 trans->block_rsv = rc->block_rsv;
1345 clear_rsv = 1;
1346 }
1347 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1348 if (clear_rsv)
1349 trans->block_rsv = NULL;
1350
1351 __add_reloc_root(reloc_root);
1352 root->reloc_root = reloc_root;
1353 return 0;
1354 }
1355
1356 /*
1357 * update root item of reloc tree
1358 */
1359 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1360 struct btrfs_root *root)
1361 {
1362 struct btrfs_root *reloc_root;
1363 struct btrfs_root_item *root_item;
1364 int del = 0;
1365 int ret;
1366
1367 if (!root->reloc_root)
1368 return 0;
1369
1370 reloc_root = root->reloc_root;
1371 root_item = &reloc_root->root_item;
1372
1373 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1374 btrfs_root_refs(root_item) == 0) {
1375 root->reloc_root = NULL;
1376 del = 1;
1377 }
1378
1379 __update_reloc_root(reloc_root, del);
1380
1381 if (reloc_root->commit_root != reloc_root->node) {
1382 btrfs_set_root_node(root_item, reloc_root->node);
1383 free_extent_buffer(reloc_root->commit_root);
1384 reloc_root->commit_root = btrfs_root_node(reloc_root);
1385 }
1386
1387 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1388 &reloc_root->root_key, root_item);
1389 BUG_ON(ret);
1390 return 0;
1391 }
1392
1393 /*
1394 * helper to find first cached inode with inode number >= objectid
1395 * in a subvolume
1396 */
1397 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1398 {
1399 struct rb_node *node;
1400 struct rb_node *prev;
1401 struct btrfs_inode *entry;
1402 struct inode *inode;
1403
1404 spin_lock(&root->inode_lock);
1405 again:
1406 node = root->inode_tree.rb_node;
1407 prev = NULL;
1408 while (node) {
1409 prev = node;
1410 entry = rb_entry(node, struct btrfs_inode, rb_node);
1411
1412 if (objectid < entry->vfs_inode.i_ino)
1413 node = node->rb_left;
1414 else if (objectid > entry->vfs_inode.i_ino)
1415 node = node->rb_right;
1416 else
1417 break;
1418 }
1419 if (!node) {
1420 while (prev) {
1421 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1422 if (objectid <= entry->vfs_inode.i_ino) {
1423 node = prev;
1424 break;
1425 }
1426 prev = rb_next(prev);
1427 }
1428 }
1429 while (node) {
1430 entry = rb_entry(node, struct btrfs_inode, rb_node);
1431 inode = igrab(&entry->vfs_inode);
1432 if (inode) {
1433 spin_unlock(&root->inode_lock);
1434 return inode;
1435 }
1436
1437 objectid = entry->vfs_inode.i_ino + 1;
1438 if (cond_resched_lock(&root->inode_lock))
1439 goto again;
1440
1441 node = rb_next(node);
1442 }
1443 spin_unlock(&root->inode_lock);
1444 return NULL;
1445 }
1446
1447 static int in_block_group(u64 bytenr,
1448 struct btrfs_block_group_cache *block_group)
1449 {
1450 if (bytenr >= block_group->key.objectid &&
1451 bytenr < block_group->key.objectid + block_group->key.offset)
1452 return 1;
1453 return 0;
1454 }
1455
1456 /*
1457 * get new location of data
1458 */
1459 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1460 u64 bytenr, u64 num_bytes)
1461 {
1462 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1463 struct btrfs_path *path;
1464 struct btrfs_file_extent_item *fi;
1465 struct extent_buffer *leaf;
1466 int ret;
1467
1468 path = btrfs_alloc_path();
1469 if (!path)
1470 return -ENOMEM;
1471
1472 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1473 ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
1474 bytenr, 0);
1475 if (ret < 0)
1476 goto out;
1477 if (ret > 0) {
1478 ret = -ENOENT;
1479 goto out;
1480 }
1481
1482 leaf = path->nodes[0];
1483 fi = btrfs_item_ptr(leaf, path->slots[0],
1484 struct btrfs_file_extent_item);
1485
1486 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1487 btrfs_file_extent_compression(leaf, fi) ||
1488 btrfs_file_extent_encryption(leaf, fi) ||
1489 btrfs_file_extent_other_encoding(leaf, fi));
1490
1491 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1492 ret = 1;
1493 goto out;
1494 }
1495
1496 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1497 ret = 0;
1498 out:
1499 btrfs_free_path(path);
1500 return ret;
1501 }
1502
1503 /*
1504 * update file extent items in the tree leaf to point to
1505 * the new locations.
1506 */
1507 static noinline_for_stack
1508 int replace_file_extents(struct btrfs_trans_handle *trans,
1509 struct reloc_control *rc,
1510 struct btrfs_root *root,
1511 struct extent_buffer *leaf)
1512 {
1513 struct btrfs_key key;
1514 struct btrfs_file_extent_item *fi;
1515 struct inode *inode = NULL;
1516 u64 parent;
1517 u64 bytenr;
1518 u64 new_bytenr = 0;
1519 u64 num_bytes;
1520 u64 end;
1521 u32 nritems;
1522 u32 i;
1523 int ret;
1524 int first = 1;
1525 int dirty = 0;
1526
1527 if (rc->stage != UPDATE_DATA_PTRS)
1528 return 0;
1529
1530 /* reloc trees always use full backref */
1531 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1532 parent = leaf->start;
1533 else
1534 parent = 0;
1535
1536 nritems = btrfs_header_nritems(leaf);
1537 for (i = 0; i < nritems; i++) {
1538 cond_resched();
1539 btrfs_item_key_to_cpu(leaf, &key, i);
1540 if (key.type != BTRFS_EXTENT_DATA_KEY)
1541 continue;
1542 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1543 if (btrfs_file_extent_type(leaf, fi) ==
1544 BTRFS_FILE_EXTENT_INLINE)
1545 continue;
1546 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1547 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1548 if (bytenr == 0)
1549 continue;
1550 if (!in_block_group(bytenr, rc->block_group))
1551 continue;
1552
1553 /*
1554 * if we are modifying block in fs tree, wait for readpage
1555 * to complete and drop the extent cache
1556 */
1557 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1558 if (first) {
1559 inode = find_next_inode(root, key.objectid);
1560 first = 0;
1561 } else if (inode && inode->i_ino < key.objectid) {
1562 btrfs_add_delayed_iput(inode);
1563 inode = find_next_inode(root, key.objectid);
1564 }
1565 if (inode && inode->i_ino == key.objectid) {
1566 end = key.offset +
1567 btrfs_file_extent_num_bytes(leaf, fi);
1568 WARN_ON(!IS_ALIGNED(key.offset,
1569 root->sectorsize));
1570 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1571 end--;
1572 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1573 key.offset, end,
1574 GFP_NOFS);
1575 if (!ret)
1576 continue;
1577
1578 btrfs_drop_extent_cache(inode, key.offset, end,
1579 1);
1580 unlock_extent(&BTRFS_I(inode)->io_tree,
1581 key.offset, end, GFP_NOFS);
1582 }
1583 }
1584
1585 ret = get_new_location(rc->data_inode, &new_bytenr,
1586 bytenr, num_bytes);
1587 if (ret > 0) {
1588 WARN_ON(1);
1589 continue;
1590 }
1591 BUG_ON(ret < 0);
1592
1593 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1594 dirty = 1;
1595
1596 key.offset -= btrfs_file_extent_offset(leaf, fi);
1597 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1598 num_bytes, parent,
1599 btrfs_header_owner(leaf),
1600 key.objectid, key.offset);
1601 BUG_ON(ret);
1602
1603 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1604 parent, btrfs_header_owner(leaf),
1605 key.objectid, key.offset);
1606 BUG_ON(ret);
1607 }
1608 if (dirty)
1609 btrfs_mark_buffer_dirty(leaf);
1610 if (inode)
1611 btrfs_add_delayed_iput(inode);
1612 return 0;
1613 }
1614
1615 static noinline_for_stack
1616 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1617 struct btrfs_path *path, int level)
1618 {
1619 struct btrfs_disk_key key1;
1620 struct btrfs_disk_key key2;
1621 btrfs_node_key(eb, &key1, slot);
1622 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1623 return memcmp(&key1, &key2, sizeof(key1));
1624 }
1625
1626 /*
1627 * try to replace tree blocks in fs tree with the new blocks
1628 * in reloc tree. tree blocks haven't been modified since the
1629 * reloc tree was create can be replaced.
1630 *
1631 * if a block was replaced, level of the block + 1 is returned.
1632 * if no block got replaced, 0 is returned. if there are other
1633 * errors, a negative error number is returned.
1634 */
1635 static noinline_for_stack
1636 int replace_path(struct btrfs_trans_handle *trans,
1637 struct btrfs_root *dest, struct btrfs_root *src,
1638 struct btrfs_path *path, struct btrfs_key *next_key,
1639 int lowest_level, int max_level)
1640 {
1641 struct extent_buffer *eb;
1642 struct extent_buffer *parent;
1643 struct btrfs_key key;
1644 u64 old_bytenr;
1645 u64 new_bytenr;
1646 u64 old_ptr_gen;
1647 u64 new_ptr_gen;
1648 u64 last_snapshot;
1649 u32 blocksize;
1650 int cow = 0;
1651 int level;
1652 int ret;
1653 int slot;
1654
1655 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1656 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1657
1658 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1659 again:
1660 slot = path->slots[lowest_level];
1661 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1662
1663 eb = btrfs_lock_root_node(dest);
1664 btrfs_set_lock_blocking(eb);
1665 level = btrfs_header_level(eb);
1666
1667 if (level < lowest_level) {
1668 btrfs_tree_unlock(eb);
1669 free_extent_buffer(eb);
1670 return 0;
1671 }
1672
1673 if (cow) {
1674 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1675 BUG_ON(ret);
1676 }
1677 btrfs_set_lock_blocking(eb);
1678
1679 if (next_key) {
1680 next_key->objectid = (u64)-1;
1681 next_key->type = (u8)-1;
1682 next_key->offset = (u64)-1;
1683 }
1684
1685 parent = eb;
1686 while (1) {
1687 level = btrfs_header_level(parent);
1688 BUG_ON(level < lowest_level);
1689
1690 ret = btrfs_bin_search(parent, &key, level, &slot);
1691 if (ret && slot > 0)
1692 slot--;
1693
1694 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1695 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1696
1697 old_bytenr = btrfs_node_blockptr(parent, slot);
1698 blocksize = btrfs_level_size(dest, level - 1);
1699 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1700
1701 if (level <= max_level) {
1702 eb = path->nodes[level];
1703 new_bytenr = btrfs_node_blockptr(eb,
1704 path->slots[level]);
1705 new_ptr_gen = btrfs_node_ptr_generation(eb,
1706 path->slots[level]);
1707 } else {
1708 new_bytenr = 0;
1709 new_ptr_gen = 0;
1710 }
1711
1712 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1713 WARN_ON(1);
1714 ret = level;
1715 break;
1716 }
1717
1718 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1719 memcmp_node_keys(parent, slot, path, level)) {
1720 if (level <= lowest_level) {
1721 ret = 0;
1722 break;
1723 }
1724
1725 eb = read_tree_block(dest, old_bytenr, blocksize,
1726 old_ptr_gen);
1727 btrfs_tree_lock(eb);
1728 if (cow) {
1729 ret = btrfs_cow_block(trans, dest, eb, parent,
1730 slot, &eb);
1731 BUG_ON(ret);
1732 }
1733 btrfs_set_lock_blocking(eb);
1734
1735 btrfs_tree_unlock(parent);
1736 free_extent_buffer(parent);
1737
1738 parent = eb;
1739 continue;
1740 }
1741
1742 if (!cow) {
1743 btrfs_tree_unlock(parent);
1744 free_extent_buffer(parent);
1745 cow = 1;
1746 goto again;
1747 }
1748
1749 btrfs_node_key_to_cpu(path->nodes[level], &key,
1750 path->slots[level]);
1751 btrfs_release_path(src, path);
1752
1753 path->lowest_level = level;
1754 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1755 path->lowest_level = 0;
1756 BUG_ON(ret);
1757
1758 /*
1759 * swap blocks in fs tree and reloc tree.
1760 */
1761 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1762 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1763 btrfs_mark_buffer_dirty(parent);
1764
1765 btrfs_set_node_blockptr(path->nodes[level],
1766 path->slots[level], old_bytenr);
1767 btrfs_set_node_ptr_generation(path->nodes[level],
1768 path->slots[level], old_ptr_gen);
1769 btrfs_mark_buffer_dirty(path->nodes[level]);
1770
1771 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1772 path->nodes[level]->start,
1773 src->root_key.objectid, level - 1, 0);
1774 BUG_ON(ret);
1775 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1776 0, dest->root_key.objectid, level - 1,
1777 0);
1778 BUG_ON(ret);
1779
1780 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1781 path->nodes[level]->start,
1782 src->root_key.objectid, level - 1, 0);
1783 BUG_ON(ret);
1784
1785 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1786 0, dest->root_key.objectid, level - 1,
1787 0);
1788 BUG_ON(ret);
1789
1790 btrfs_unlock_up_safe(path, 0);
1791
1792 ret = level;
1793 break;
1794 }
1795 btrfs_tree_unlock(parent);
1796 free_extent_buffer(parent);
1797 return ret;
1798 }
1799
1800 /*
1801 * helper to find next relocated block in reloc tree
1802 */
1803 static noinline_for_stack
1804 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1805 int *level)
1806 {
1807 struct extent_buffer *eb;
1808 int i;
1809 u64 last_snapshot;
1810 u32 nritems;
1811
1812 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1813
1814 for (i = 0; i < *level; i++) {
1815 free_extent_buffer(path->nodes[i]);
1816 path->nodes[i] = NULL;
1817 }
1818
1819 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1820 eb = path->nodes[i];
1821 nritems = btrfs_header_nritems(eb);
1822 while (path->slots[i] + 1 < nritems) {
1823 path->slots[i]++;
1824 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1825 last_snapshot)
1826 continue;
1827
1828 *level = i;
1829 return 0;
1830 }
1831 free_extent_buffer(path->nodes[i]);
1832 path->nodes[i] = NULL;
1833 }
1834 return 1;
1835 }
1836
1837 /*
1838 * walk down reloc tree to find relocated block of lowest level
1839 */
1840 static noinline_for_stack
1841 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1842 int *level)
1843 {
1844 struct extent_buffer *eb = NULL;
1845 int i;
1846 u64 bytenr;
1847 u64 ptr_gen = 0;
1848 u64 last_snapshot;
1849 u32 blocksize;
1850 u32 nritems;
1851
1852 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1853
1854 for (i = *level; i > 0; i--) {
1855 eb = path->nodes[i];
1856 nritems = btrfs_header_nritems(eb);
1857 while (path->slots[i] < nritems) {
1858 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1859 if (ptr_gen > last_snapshot)
1860 break;
1861 path->slots[i]++;
1862 }
1863 if (path->slots[i] >= nritems) {
1864 if (i == *level)
1865 break;
1866 *level = i + 1;
1867 return 0;
1868 }
1869 if (i == 1) {
1870 *level = i;
1871 return 0;
1872 }
1873
1874 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1875 blocksize = btrfs_level_size(root, i - 1);
1876 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1877 BUG_ON(btrfs_header_level(eb) != i - 1);
1878 path->nodes[i - 1] = eb;
1879 path->slots[i - 1] = 0;
1880 }
1881 return 1;
1882 }
1883
1884 /*
1885 * invalidate extent cache for file extents whose key in range of
1886 * [min_key, max_key)
1887 */
1888 static int invalidate_extent_cache(struct btrfs_root *root,
1889 struct btrfs_key *min_key,
1890 struct btrfs_key *max_key)
1891 {
1892 struct inode *inode = NULL;
1893 u64 objectid;
1894 u64 start, end;
1895
1896 objectid = min_key->objectid;
1897 while (1) {
1898 cond_resched();
1899 iput(inode);
1900
1901 if (objectid > max_key->objectid)
1902 break;
1903
1904 inode = find_next_inode(root, objectid);
1905 if (!inode)
1906 break;
1907
1908 if (inode->i_ino > max_key->objectid) {
1909 iput(inode);
1910 break;
1911 }
1912
1913 objectid = inode->i_ino + 1;
1914 if (!S_ISREG(inode->i_mode))
1915 continue;
1916
1917 if (unlikely(min_key->objectid == inode->i_ino)) {
1918 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1919 continue;
1920 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1921 start = 0;
1922 else {
1923 start = min_key->offset;
1924 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1925 }
1926 } else {
1927 start = 0;
1928 }
1929
1930 if (unlikely(max_key->objectid == inode->i_ino)) {
1931 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1932 continue;
1933 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1934 end = (u64)-1;
1935 } else {
1936 if (max_key->offset == 0)
1937 continue;
1938 end = max_key->offset;
1939 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1940 end--;
1941 }
1942 } else {
1943 end = (u64)-1;
1944 }
1945
1946 /* the lock_extent waits for readpage to complete */
1947 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1948 btrfs_drop_extent_cache(inode, start, end, 1);
1949 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1950 }
1951 return 0;
1952 }
1953
1954 static int find_next_key(struct btrfs_path *path, int level,
1955 struct btrfs_key *key)
1956
1957 {
1958 while (level < BTRFS_MAX_LEVEL) {
1959 if (!path->nodes[level])
1960 break;
1961 if (path->slots[level] + 1 <
1962 btrfs_header_nritems(path->nodes[level])) {
1963 btrfs_node_key_to_cpu(path->nodes[level], key,
1964 path->slots[level] + 1);
1965 return 0;
1966 }
1967 level++;
1968 }
1969 return 1;
1970 }
1971
1972 /*
1973 * merge the relocated tree blocks in reloc tree with corresponding
1974 * fs tree.
1975 */
1976 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1977 struct btrfs_root *root)
1978 {
1979 LIST_HEAD(inode_list);
1980 struct btrfs_key key;
1981 struct btrfs_key next_key;
1982 struct btrfs_trans_handle *trans;
1983 struct btrfs_root *reloc_root;
1984 struct btrfs_root_item *root_item;
1985 struct btrfs_path *path;
1986 struct extent_buffer *leaf;
1987 unsigned long nr;
1988 int level;
1989 int max_level;
1990 int replaced = 0;
1991 int ret;
1992 int err = 0;
1993 u32 min_reserved;
1994
1995 path = btrfs_alloc_path();
1996 if (!path)
1997 return -ENOMEM;
1998
1999 reloc_root = root->reloc_root;
2000 root_item = &reloc_root->root_item;
2001
2002 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2003 level = btrfs_root_level(root_item);
2004 extent_buffer_get(reloc_root->node);
2005 path->nodes[level] = reloc_root->node;
2006 path->slots[level] = 0;
2007 } else {
2008 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2009
2010 level = root_item->drop_level;
2011 BUG_ON(level == 0);
2012 path->lowest_level = level;
2013 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2014 path->lowest_level = 0;
2015 if (ret < 0) {
2016 btrfs_free_path(path);
2017 return ret;
2018 }
2019
2020 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2021 path->slots[level]);
2022 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2023
2024 btrfs_unlock_up_safe(path, 0);
2025 }
2026
2027 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2028 memset(&next_key, 0, sizeof(next_key));
2029
2030 while (1) {
2031 trans = btrfs_start_transaction(root, 0);
2032 BUG_ON(IS_ERR(trans));
2033 trans->block_rsv = rc->block_rsv;
2034
2035 ret = btrfs_block_rsv_check(trans, root, rc->block_rsv,
2036 min_reserved, 0);
2037 if (ret) {
2038 BUG_ON(ret != -EAGAIN);
2039 ret = btrfs_commit_transaction(trans, root);
2040 BUG_ON(ret);
2041 continue;
2042 }
2043
2044 replaced = 0;
2045 max_level = level;
2046
2047 ret = walk_down_reloc_tree(reloc_root, path, &level);
2048 if (ret < 0) {
2049 err = ret;
2050 goto out;
2051 }
2052 if (ret > 0)
2053 break;
2054
2055 if (!find_next_key(path, level, &key) &&
2056 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2057 ret = 0;
2058 } else {
2059 ret = replace_path(trans, root, reloc_root, path,
2060 &next_key, level, max_level);
2061 }
2062 if (ret < 0) {
2063 err = ret;
2064 goto out;
2065 }
2066
2067 if (ret > 0) {
2068 level = ret;
2069 btrfs_node_key_to_cpu(path->nodes[level], &key,
2070 path->slots[level]);
2071 replaced = 1;
2072 }
2073
2074 ret = walk_up_reloc_tree(reloc_root, path, &level);
2075 if (ret > 0)
2076 break;
2077
2078 BUG_ON(level == 0);
2079 /*
2080 * save the merging progress in the drop_progress.
2081 * this is OK since root refs == 1 in this case.
2082 */
2083 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2084 path->slots[level]);
2085 root_item->drop_level = level;
2086
2087 nr = trans->blocks_used;
2088 btrfs_end_transaction_throttle(trans, root);
2089
2090 btrfs_btree_balance_dirty(root, nr);
2091
2092 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2093 invalidate_extent_cache(root, &key, &next_key);
2094 }
2095
2096 /*
2097 * handle the case only one block in the fs tree need to be
2098 * relocated and the block is tree root.
2099 */
2100 leaf = btrfs_lock_root_node(root);
2101 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2102 btrfs_tree_unlock(leaf);
2103 free_extent_buffer(leaf);
2104 if (ret < 0)
2105 err = ret;
2106 out:
2107 btrfs_free_path(path);
2108
2109 if (err == 0) {
2110 memset(&root_item->drop_progress, 0,
2111 sizeof(root_item->drop_progress));
2112 root_item->drop_level = 0;
2113 btrfs_set_root_refs(root_item, 0);
2114 btrfs_update_reloc_root(trans, root);
2115 }
2116
2117 nr = trans->blocks_used;
2118 btrfs_end_transaction_throttle(trans, root);
2119
2120 btrfs_btree_balance_dirty(root, nr);
2121
2122 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2123 invalidate_extent_cache(root, &key, &next_key);
2124
2125 return err;
2126 }
2127
2128 static noinline_for_stack
2129 int prepare_to_merge(struct reloc_control *rc, int err)
2130 {
2131 struct btrfs_root *root = rc->extent_root;
2132 struct btrfs_root *reloc_root;
2133 struct btrfs_trans_handle *trans;
2134 LIST_HEAD(reloc_roots);
2135 u64 num_bytes = 0;
2136 int ret;
2137
2138 mutex_lock(&root->fs_info->trans_mutex);
2139 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2140 rc->merging_rsv_size += rc->nodes_relocated * 2;
2141 mutex_unlock(&root->fs_info->trans_mutex);
2142 again:
2143 if (!err) {
2144 num_bytes = rc->merging_rsv_size;
2145 ret = btrfs_block_rsv_add(NULL, root, rc->block_rsv,
2146 num_bytes);
2147 if (ret)
2148 err = ret;
2149 }
2150
2151 trans = btrfs_join_transaction(rc->extent_root, 1);
2152 if (IS_ERR(trans)) {
2153 if (!err)
2154 btrfs_block_rsv_release(rc->extent_root,
2155 rc->block_rsv, num_bytes);
2156 return PTR_ERR(trans);
2157 }
2158
2159 if (!err) {
2160 if (num_bytes != rc->merging_rsv_size) {
2161 btrfs_end_transaction(trans, rc->extent_root);
2162 btrfs_block_rsv_release(rc->extent_root,
2163 rc->block_rsv, num_bytes);
2164 goto again;
2165 }
2166 }
2167
2168 rc->merge_reloc_tree = 1;
2169
2170 while (!list_empty(&rc->reloc_roots)) {
2171 reloc_root = list_entry(rc->reloc_roots.next,
2172 struct btrfs_root, root_list);
2173 list_del_init(&reloc_root->root_list);
2174
2175 root = read_fs_root(reloc_root->fs_info,
2176 reloc_root->root_key.offset);
2177 BUG_ON(IS_ERR(root));
2178 BUG_ON(root->reloc_root != reloc_root);
2179
2180 /*
2181 * set reference count to 1, so btrfs_recover_relocation
2182 * knows it should resumes merging
2183 */
2184 if (!err)
2185 btrfs_set_root_refs(&reloc_root->root_item, 1);
2186 btrfs_update_reloc_root(trans, root);
2187
2188 list_add(&reloc_root->root_list, &reloc_roots);
2189 }
2190
2191 list_splice(&reloc_roots, &rc->reloc_roots);
2192
2193 if (!err)
2194 btrfs_commit_transaction(trans, rc->extent_root);
2195 else
2196 btrfs_end_transaction(trans, rc->extent_root);
2197 return err;
2198 }
2199
2200 static noinline_for_stack
2201 int merge_reloc_roots(struct reloc_control *rc)
2202 {
2203 struct btrfs_root *root;
2204 struct btrfs_root *reloc_root;
2205 LIST_HEAD(reloc_roots);
2206 int found = 0;
2207 int ret;
2208 again:
2209 root = rc->extent_root;
2210 mutex_lock(&root->fs_info->trans_mutex);
2211 list_splice_init(&rc->reloc_roots, &reloc_roots);
2212 mutex_unlock(&root->fs_info->trans_mutex);
2213
2214 while (!list_empty(&reloc_roots)) {
2215 found = 1;
2216 reloc_root = list_entry(reloc_roots.next,
2217 struct btrfs_root, root_list);
2218
2219 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2220 root = read_fs_root(reloc_root->fs_info,
2221 reloc_root->root_key.offset);
2222 BUG_ON(IS_ERR(root));
2223 BUG_ON(root->reloc_root != reloc_root);
2224
2225 ret = merge_reloc_root(rc, root);
2226 BUG_ON(ret);
2227 } else {
2228 list_del_init(&reloc_root->root_list);
2229 }
2230 btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0);
2231 }
2232
2233 if (found) {
2234 found = 0;
2235 goto again;
2236 }
2237 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2238 return 0;
2239 }
2240
2241 static void free_block_list(struct rb_root *blocks)
2242 {
2243 struct tree_block *block;
2244 struct rb_node *rb_node;
2245 while ((rb_node = rb_first(blocks))) {
2246 block = rb_entry(rb_node, struct tree_block, rb_node);
2247 rb_erase(rb_node, blocks);
2248 kfree(block);
2249 }
2250 }
2251
2252 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2253 struct btrfs_root *reloc_root)
2254 {
2255 struct btrfs_root *root;
2256
2257 if (reloc_root->last_trans == trans->transid)
2258 return 0;
2259
2260 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2261 BUG_ON(IS_ERR(root));
2262 BUG_ON(root->reloc_root != reloc_root);
2263
2264 return btrfs_record_root_in_trans(trans, root);
2265 }
2266
2267 static noinline_for_stack
2268 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2269 struct reloc_control *rc,
2270 struct backref_node *node,
2271 struct backref_edge *edges[], int *nr)
2272 {
2273 struct backref_node *next;
2274 struct btrfs_root *root;
2275 int index = 0;
2276
2277 next = node;
2278 while (1) {
2279 cond_resched();
2280 next = walk_up_backref(next, edges, &index);
2281 root = next->root;
2282 BUG_ON(!root);
2283 BUG_ON(!root->ref_cows);
2284
2285 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2286 record_reloc_root_in_trans(trans, root);
2287 break;
2288 }
2289
2290 btrfs_record_root_in_trans(trans, root);
2291 root = root->reloc_root;
2292
2293 if (next->new_bytenr != root->node->start) {
2294 BUG_ON(next->new_bytenr);
2295 BUG_ON(!list_empty(&next->list));
2296 next->new_bytenr = root->node->start;
2297 next->root = root;
2298 list_add_tail(&next->list,
2299 &rc->backref_cache.changed);
2300 __mark_block_processed(rc, next);
2301 break;
2302 }
2303
2304 WARN_ON(1);
2305 root = NULL;
2306 next = walk_down_backref(edges, &index);
2307 if (!next || next->level <= node->level)
2308 break;
2309 }
2310 if (!root)
2311 return NULL;
2312
2313 *nr = index;
2314 next = node;
2315 /* setup backref node path for btrfs_reloc_cow_block */
2316 while (1) {
2317 rc->backref_cache.path[next->level] = next;
2318 if (--index < 0)
2319 break;
2320 next = edges[index]->node[UPPER];
2321 }
2322 return root;
2323 }
2324
2325 /*
2326 * select a tree root for relocation. return NULL if the block
2327 * is reference counted. we should use do_relocation() in this
2328 * case. return a tree root pointer if the block isn't reference
2329 * counted. return -ENOENT if the block is root of reloc tree.
2330 */
2331 static noinline_for_stack
2332 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2333 struct backref_node *node)
2334 {
2335 struct backref_node *next;
2336 struct btrfs_root *root;
2337 struct btrfs_root *fs_root = NULL;
2338 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2339 int index = 0;
2340
2341 next = node;
2342 while (1) {
2343 cond_resched();
2344 next = walk_up_backref(next, edges, &index);
2345 root = next->root;
2346 BUG_ON(!root);
2347
2348 /* no other choice for non-refernce counted tree */
2349 if (!root->ref_cows)
2350 return root;
2351
2352 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2353 fs_root = root;
2354
2355 if (next != node)
2356 return NULL;
2357
2358 next = walk_down_backref(edges, &index);
2359 if (!next || next->level <= node->level)
2360 break;
2361 }
2362
2363 if (!fs_root)
2364 return ERR_PTR(-ENOENT);
2365 return fs_root;
2366 }
2367
2368 static noinline_for_stack
2369 u64 calcu_metadata_size(struct reloc_control *rc,
2370 struct backref_node *node, int reserve)
2371 {
2372 struct backref_node *next = node;
2373 struct backref_edge *edge;
2374 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2375 u64 num_bytes = 0;
2376 int index = 0;
2377
2378 BUG_ON(reserve && node->processed);
2379
2380 while (next) {
2381 cond_resched();
2382 while (1) {
2383 if (next->processed && (reserve || next != node))
2384 break;
2385
2386 num_bytes += btrfs_level_size(rc->extent_root,
2387 next->level);
2388
2389 if (list_empty(&next->upper))
2390 break;
2391
2392 edge = list_entry(next->upper.next,
2393 struct backref_edge, list[LOWER]);
2394 edges[index++] = edge;
2395 next = edge->node[UPPER];
2396 }
2397 next = walk_down_backref(edges, &index);
2398 }
2399 return num_bytes;
2400 }
2401
2402 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2403 struct reloc_control *rc,
2404 struct backref_node *node)
2405 {
2406 struct btrfs_root *root = rc->extent_root;
2407 u64 num_bytes;
2408 int ret;
2409
2410 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2411
2412 trans->block_rsv = rc->block_rsv;
2413 ret = btrfs_block_rsv_add(trans, root, rc->block_rsv, num_bytes);
2414 if (ret) {
2415 if (ret == -EAGAIN)
2416 rc->commit_transaction = 1;
2417 return ret;
2418 }
2419
2420 return 0;
2421 }
2422
2423 static void release_metadata_space(struct reloc_control *rc,
2424 struct backref_node *node)
2425 {
2426 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2427 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2428 }
2429
2430 /*
2431 * relocate a block tree, and then update pointers in upper level
2432 * blocks that reference the block to point to the new location.
2433 *
2434 * if called by link_to_upper, the block has already been relocated.
2435 * in that case this function just updates pointers.
2436 */
2437 static int do_relocation(struct btrfs_trans_handle *trans,
2438 struct reloc_control *rc,
2439 struct backref_node *node,
2440 struct btrfs_key *key,
2441 struct btrfs_path *path, int lowest)
2442 {
2443 struct backref_node *upper;
2444 struct backref_edge *edge;
2445 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2446 struct btrfs_root *root;
2447 struct extent_buffer *eb;
2448 u32 blocksize;
2449 u64 bytenr;
2450 u64 generation;
2451 int nr;
2452 int slot;
2453 int ret;
2454 int err = 0;
2455
2456 BUG_ON(lowest && node->eb);
2457
2458 path->lowest_level = node->level + 1;
2459 rc->backref_cache.path[node->level] = node;
2460 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2461 cond_resched();
2462
2463 upper = edge->node[UPPER];
2464 root = select_reloc_root(trans, rc, upper, edges, &nr);
2465 BUG_ON(!root);
2466
2467 if (upper->eb && !upper->locked) {
2468 if (!lowest) {
2469 ret = btrfs_bin_search(upper->eb, key,
2470 upper->level, &slot);
2471 BUG_ON(ret);
2472 bytenr = btrfs_node_blockptr(upper->eb, slot);
2473 if (node->eb->start == bytenr)
2474 goto next;
2475 }
2476 drop_node_buffer(upper);
2477 }
2478
2479 if (!upper->eb) {
2480 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2481 if (ret < 0) {
2482 err = ret;
2483 break;
2484 }
2485 BUG_ON(ret > 0);
2486
2487 if (!upper->eb) {
2488 upper->eb = path->nodes[upper->level];
2489 path->nodes[upper->level] = NULL;
2490 } else {
2491 BUG_ON(upper->eb != path->nodes[upper->level]);
2492 }
2493
2494 upper->locked = 1;
2495 path->locks[upper->level] = 0;
2496
2497 slot = path->slots[upper->level];
2498 btrfs_release_path(NULL, path);
2499 } else {
2500 ret = btrfs_bin_search(upper->eb, key, upper->level,
2501 &slot);
2502 BUG_ON(ret);
2503 }
2504
2505 bytenr = btrfs_node_blockptr(upper->eb, slot);
2506 if (lowest) {
2507 BUG_ON(bytenr != node->bytenr);
2508 } else {
2509 if (node->eb->start == bytenr)
2510 goto next;
2511 }
2512
2513 blocksize = btrfs_level_size(root, node->level);
2514 generation = btrfs_node_ptr_generation(upper->eb, slot);
2515 eb = read_tree_block(root, bytenr, blocksize, generation);
2516 btrfs_tree_lock(eb);
2517 btrfs_set_lock_blocking(eb);
2518
2519 if (!node->eb) {
2520 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2521 slot, &eb);
2522 btrfs_tree_unlock(eb);
2523 free_extent_buffer(eb);
2524 if (ret < 0) {
2525 err = ret;
2526 goto next;
2527 }
2528 BUG_ON(node->eb != eb);
2529 } else {
2530 btrfs_set_node_blockptr(upper->eb, slot,
2531 node->eb->start);
2532 btrfs_set_node_ptr_generation(upper->eb, slot,
2533 trans->transid);
2534 btrfs_mark_buffer_dirty(upper->eb);
2535
2536 ret = btrfs_inc_extent_ref(trans, root,
2537 node->eb->start, blocksize,
2538 upper->eb->start,
2539 btrfs_header_owner(upper->eb),
2540 node->level, 0);
2541 BUG_ON(ret);
2542
2543 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2544 BUG_ON(ret);
2545 }
2546 next:
2547 if (!upper->pending)
2548 drop_node_buffer(upper);
2549 else
2550 unlock_node_buffer(upper);
2551 if (err)
2552 break;
2553 }
2554
2555 if (!err && node->pending) {
2556 drop_node_buffer(node);
2557 list_move_tail(&node->list, &rc->backref_cache.changed);
2558 node->pending = 0;
2559 }
2560
2561 path->lowest_level = 0;
2562 BUG_ON(err == -ENOSPC);
2563 return err;
2564 }
2565
2566 static int link_to_upper(struct btrfs_trans_handle *trans,
2567 struct reloc_control *rc,
2568 struct backref_node *node,
2569 struct btrfs_path *path)
2570 {
2571 struct btrfs_key key;
2572
2573 btrfs_node_key_to_cpu(node->eb, &key, 0);
2574 return do_relocation(trans, rc, node, &key, path, 0);
2575 }
2576
2577 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2578 struct reloc_control *rc,
2579 struct btrfs_path *path, int err)
2580 {
2581 LIST_HEAD(list);
2582 struct backref_cache *cache = &rc->backref_cache;
2583 struct backref_node *node;
2584 int level;
2585 int ret;
2586
2587 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2588 while (!list_empty(&cache->pending[level])) {
2589 node = list_entry(cache->pending[level].next,
2590 struct backref_node, list);
2591 list_move_tail(&node->list, &list);
2592 BUG_ON(!node->pending);
2593
2594 if (!err) {
2595 ret = link_to_upper(trans, rc, node, path);
2596 if (ret < 0)
2597 err = ret;
2598 }
2599 }
2600 list_splice_init(&list, &cache->pending[level]);
2601 }
2602 return err;
2603 }
2604
2605 static void mark_block_processed(struct reloc_control *rc,
2606 u64 bytenr, u32 blocksize)
2607 {
2608 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2609 EXTENT_DIRTY, GFP_NOFS);
2610 }
2611
2612 static void __mark_block_processed(struct reloc_control *rc,
2613 struct backref_node *node)
2614 {
2615 u32 blocksize;
2616 if (node->level == 0 ||
2617 in_block_group(node->bytenr, rc->block_group)) {
2618 blocksize = btrfs_level_size(rc->extent_root, node->level);
2619 mark_block_processed(rc, node->bytenr, blocksize);
2620 }
2621 node->processed = 1;
2622 }
2623
2624 /*
2625 * mark a block and all blocks directly/indirectly reference the block
2626 * as processed.
2627 */
2628 static void update_processed_blocks(struct reloc_control *rc,
2629 struct backref_node *node)
2630 {
2631 struct backref_node *next = node;
2632 struct backref_edge *edge;
2633 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2634 int index = 0;
2635
2636 while (next) {
2637 cond_resched();
2638 while (1) {
2639 if (next->processed)
2640 break;
2641
2642 __mark_block_processed(rc, next);
2643
2644 if (list_empty(&next->upper))
2645 break;
2646
2647 edge = list_entry(next->upper.next,
2648 struct backref_edge, list[LOWER]);
2649 edges[index++] = edge;
2650 next = edge->node[UPPER];
2651 }
2652 next = walk_down_backref(edges, &index);
2653 }
2654 }
2655
2656 static int tree_block_processed(u64 bytenr, u32 blocksize,
2657 struct reloc_control *rc)
2658 {
2659 if (test_range_bit(&rc->processed_blocks, bytenr,
2660 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2661 return 1;
2662 return 0;
2663 }
2664
2665 static int get_tree_block_key(struct reloc_control *rc,
2666 struct tree_block *block)
2667 {
2668 struct extent_buffer *eb;
2669
2670 BUG_ON(block->key_ready);
2671 eb = read_tree_block(rc->extent_root, block->bytenr,
2672 block->key.objectid, block->key.offset);
2673 WARN_ON(btrfs_header_level(eb) != block->level);
2674 if (block->level == 0)
2675 btrfs_item_key_to_cpu(eb, &block->key, 0);
2676 else
2677 btrfs_node_key_to_cpu(eb, &block->key, 0);
2678 free_extent_buffer(eb);
2679 block->key_ready = 1;
2680 return 0;
2681 }
2682
2683 static int reada_tree_block(struct reloc_control *rc,
2684 struct tree_block *block)
2685 {
2686 BUG_ON(block->key_ready);
2687 readahead_tree_block(rc->extent_root, block->bytenr,
2688 block->key.objectid, block->key.offset);
2689 return 0;
2690 }
2691
2692 /*
2693 * helper function to relocate a tree block
2694 */
2695 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2696 struct reloc_control *rc,
2697 struct backref_node *node,
2698 struct btrfs_key *key,
2699 struct btrfs_path *path)
2700 {
2701 struct btrfs_root *root;
2702 int release = 0;
2703 int ret = 0;
2704
2705 if (!node)
2706 return 0;
2707
2708 BUG_ON(node->processed);
2709 root = select_one_root(trans, node);
2710 if (root == ERR_PTR(-ENOENT)) {
2711 update_processed_blocks(rc, node);
2712 goto out;
2713 }
2714
2715 if (!root || root->ref_cows) {
2716 ret = reserve_metadata_space(trans, rc, node);
2717 if (ret)
2718 goto out;
2719 release = 1;
2720 }
2721
2722 if (root) {
2723 if (root->ref_cows) {
2724 BUG_ON(node->new_bytenr);
2725 BUG_ON(!list_empty(&node->list));
2726 btrfs_record_root_in_trans(trans, root);
2727 root = root->reloc_root;
2728 node->new_bytenr = root->node->start;
2729 node->root = root;
2730 list_add_tail(&node->list, &rc->backref_cache.changed);
2731 } else {
2732 path->lowest_level = node->level;
2733 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2734 btrfs_release_path(root, path);
2735 if (ret > 0)
2736 ret = 0;
2737 }
2738 if (!ret)
2739 update_processed_blocks(rc, node);
2740 } else {
2741 ret = do_relocation(trans, rc, node, key, path, 1);
2742 }
2743 out:
2744 if (ret || node->level == 0 || node->cowonly) {
2745 if (release)
2746 release_metadata_space(rc, node);
2747 remove_backref_node(&rc->backref_cache, node);
2748 }
2749 return ret;
2750 }
2751
2752 /*
2753 * relocate a list of blocks
2754 */
2755 static noinline_for_stack
2756 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2757 struct reloc_control *rc, struct rb_root *blocks)
2758 {
2759 struct backref_node *node;
2760 struct btrfs_path *path;
2761 struct tree_block *block;
2762 struct rb_node *rb_node;
2763 int ret;
2764 int err = 0;
2765
2766 path = btrfs_alloc_path();
2767 if (!path)
2768 return -ENOMEM;
2769
2770 rb_node = rb_first(blocks);
2771 while (rb_node) {
2772 block = rb_entry(rb_node, struct tree_block, rb_node);
2773 if (!block->key_ready)
2774 reada_tree_block(rc, block);
2775 rb_node = rb_next(rb_node);
2776 }
2777
2778 rb_node = rb_first(blocks);
2779 while (rb_node) {
2780 block = rb_entry(rb_node, struct tree_block, rb_node);
2781 if (!block->key_ready)
2782 get_tree_block_key(rc, block);
2783 rb_node = rb_next(rb_node);
2784 }
2785
2786 rb_node = rb_first(blocks);
2787 while (rb_node) {
2788 block = rb_entry(rb_node, struct tree_block, rb_node);
2789
2790 node = build_backref_tree(rc, &block->key,
2791 block->level, block->bytenr);
2792 if (IS_ERR(node)) {
2793 err = PTR_ERR(node);
2794 goto out;
2795 }
2796
2797 ret = relocate_tree_block(trans, rc, node, &block->key,
2798 path);
2799 if (ret < 0) {
2800 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2801 err = ret;
2802 goto out;
2803 }
2804 rb_node = rb_next(rb_node);
2805 }
2806 out:
2807 free_block_list(blocks);
2808 err = finish_pending_nodes(trans, rc, path, err);
2809
2810 btrfs_free_path(path);
2811 return err;
2812 }
2813
2814 static noinline_for_stack
2815 int prealloc_file_extent_cluster(struct inode *inode,
2816 struct file_extent_cluster *cluster)
2817 {
2818 u64 alloc_hint = 0;
2819 u64 start;
2820 u64 end;
2821 u64 offset = BTRFS_I(inode)->index_cnt;
2822 u64 num_bytes;
2823 int nr = 0;
2824 int ret = 0;
2825
2826 BUG_ON(cluster->start != cluster->boundary[0]);
2827 mutex_lock(&inode->i_mutex);
2828
2829 ret = btrfs_check_data_free_space(inode, cluster->end +
2830 1 - cluster->start);
2831 if (ret)
2832 goto out;
2833
2834 while (nr < cluster->nr) {
2835 start = cluster->boundary[nr] - offset;
2836 if (nr + 1 < cluster->nr)
2837 end = cluster->boundary[nr + 1] - 1 - offset;
2838 else
2839 end = cluster->end - offset;
2840
2841 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2842 num_bytes = end + 1 - start;
2843 ret = btrfs_prealloc_file_range(inode, 0, start,
2844 num_bytes, num_bytes,
2845 end + 1, &alloc_hint);
2846 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2847 if (ret)
2848 break;
2849 nr++;
2850 }
2851 btrfs_free_reserved_data_space(inode, cluster->end +
2852 1 - cluster->start);
2853 out:
2854 mutex_unlock(&inode->i_mutex);
2855 return ret;
2856 }
2857
2858 static noinline_for_stack
2859 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
2860 u64 block_start)
2861 {
2862 struct btrfs_root *root = BTRFS_I(inode)->root;
2863 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2864 struct extent_map *em;
2865 int ret = 0;
2866
2867 em = alloc_extent_map(GFP_NOFS);
2868 if (!em)
2869 return -ENOMEM;
2870
2871 em->start = start;
2872 em->len = end + 1 - start;
2873 em->block_len = em->len;
2874 em->block_start = block_start;
2875 em->bdev = root->fs_info->fs_devices->latest_bdev;
2876 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2877
2878 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2879 while (1) {
2880 write_lock(&em_tree->lock);
2881 ret = add_extent_mapping(em_tree, em);
2882 write_unlock(&em_tree->lock);
2883 if (ret != -EEXIST) {
2884 free_extent_map(em);
2885 break;
2886 }
2887 btrfs_drop_extent_cache(inode, start, end, 0);
2888 }
2889 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2890 return ret;
2891 }
2892
2893 static int relocate_file_extent_cluster(struct inode *inode,
2894 struct file_extent_cluster *cluster)
2895 {
2896 u64 page_start;
2897 u64 page_end;
2898 u64 offset = BTRFS_I(inode)->index_cnt;
2899 unsigned long index;
2900 unsigned long last_index;
2901 struct page *page;
2902 struct file_ra_state *ra;
2903 int nr = 0;
2904 int ret = 0;
2905
2906 if (!cluster->nr)
2907 return 0;
2908
2909 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2910 if (!ra)
2911 return -ENOMEM;
2912
2913 ret = prealloc_file_extent_cluster(inode, cluster);
2914 if (ret)
2915 goto out;
2916
2917 file_ra_state_init(ra, inode->i_mapping);
2918
2919 ret = setup_extent_mapping(inode, cluster->start - offset,
2920 cluster->end - offset, cluster->start);
2921 if (ret)
2922 goto out;
2923
2924 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
2925 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
2926 while (index <= last_index) {
2927 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
2928 if (ret)
2929 goto out;
2930
2931 page = find_lock_page(inode->i_mapping, index);
2932 if (!page) {
2933 page_cache_sync_readahead(inode->i_mapping,
2934 ra, NULL, index,
2935 last_index + 1 - index);
2936 page = grab_cache_page(inode->i_mapping, index);
2937 if (!page) {
2938 btrfs_delalloc_release_metadata(inode,
2939 PAGE_CACHE_SIZE);
2940 ret = -ENOMEM;
2941 goto out;
2942 }
2943 }
2944
2945 if (PageReadahead(page)) {
2946 page_cache_async_readahead(inode->i_mapping,
2947 ra, NULL, page, index,
2948 last_index + 1 - index);
2949 }
2950
2951 if (!PageUptodate(page)) {
2952 btrfs_readpage(NULL, page);
2953 lock_page(page);
2954 if (!PageUptodate(page)) {
2955 unlock_page(page);
2956 page_cache_release(page);
2957 btrfs_delalloc_release_metadata(inode,
2958 PAGE_CACHE_SIZE);
2959 ret = -EIO;
2960 goto out;
2961 }
2962 }
2963
2964 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2965 page_end = page_start + PAGE_CACHE_SIZE - 1;
2966
2967 lock_extent(&BTRFS_I(inode)->io_tree,
2968 page_start, page_end, GFP_NOFS);
2969
2970 set_page_extent_mapped(page);
2971
2972 if (nr < cluster->nr &&
2973 page_start + offset == cluster->boundary[nr]) {
2974 set_extent_bits(&BTRFS_I(inode)->io_tree,
2975 page_start, page_end,
2976 EXTENT_BOUNDARY, GFP_NOFS);
2977 nr++;
2978 }
2979
2980 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
2981 set_page_dirty(page);
2982
2983 unlock_extent(&BTRFS_I(inode)->io_tree,
2984 page_start, page_end, GFP_NOFS);
2985 unlock_page(page);
2986 page_cache_release(page);
2987
2988 index++;
2989 balance_dirty_pages_ratelimited(inode->i_mapping);
2990 btrfs_throttle(BTRFS_I(inode)->root);
2991 }
2992 WARN_ON(nr != cluster->nr);
2993 out:
2994 kfree(ra);
2995 return ret;
2996 }
2997
2998 static noinline_for_stack
2999 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3000 struct file_extent_cluster *cluster)
3001 {
3002 int ret;
3003
3004 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3005 ret = relocate_file_extent_cluster(inode, cluster);
3006 if (ret)
3007 return ret;
3008 cluster->nr = 0;
3009 }
3010
3011 if (!cluster->nr)
3012 cluster->start = extent_key->objectid;
3013 else
3014 BUG_ON(cluster->nr >= MAX_EXTENTS);
3015 cluster->end = extent_key->objectid + extent_key->offset - 1;
3016 cluster->boundary[cluster->nr] = extent_key->objectid;
3017 cluster->nr++;
3018
3019 if (cluster->nr >= MAX_EXTENTS) {
3020 ret = relocate_file_extent_cluster(inode, cluster);
3021 if (ret)
3022 return ret;
3023 cluster->nr = 0;
3024 }
3025 return 0;
3026 }
3027
3028 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3029 static int get_ref_objectid_v0(struct reloc_control *rc,
3030 struct btrfs_path *path,
3031 struct btrfs_key *extent_key,
3032 u64 *ref_objectid, int *path_change)
3033 {
3034 struct btrfs_key key;
3035 struct extent_buffer *leaf;
3036 struct btrfs_extent_ref_v0 *ref0;
3037 int ret;
3038 int slot;
3039
3040 leaf = path->nodes[0];
3041 slot = path->slots[0];
3042 while (1) {
3043 if (slot >= btrfs_header_nritems(leaf)) {
3044 ret = btrfs_next_leaf(rc->extent_root, path);
3045 if (ret < 0)
3046 return ret;
3047 BUG_ON(ret > 0);
3048 leaf = path->nodes[0];
3049 slot = path->slots[0];
3050 if (path_change)
3051 *path_change = 1;
3052 }
3053 btrfs_item_key_to_cpu(leaf, &key, slot);
3054 if (key.objectid != extent_key->objectid)
3055 return -ENOENT;
3056
3057 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3058 slot++;
3059 continue;
3060 }
3061 ref0 = btrfs_item_ptr(leaf, slot,
3062 struct btrfs_extent_ref_v0);
3063 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3064 break;
3065 }
3066 return 0;
3067 }
3068 #endif
3069
3070 /*
3071 * helper to add a tree block to the list.
3072 * the major work is getting the generation and level of the block
3073 */
3074 static int add_tree_block(struct reloc_control *rc,
3075 struct btrfs_key *extent_key,
3076 struct btrfs_path *path,
3077 struct rb_root *blocks)
3078 {
3079 struct extent_buffer *eb;
3080 struct btrfs_extent_item *ei;
3081 struct btrfs_tree_block_info *bi;
3082 struct tree_block *block;
3083 struct rb_node *rb_node;
3084 u32 item_size;
3085 int level = -1;
3086 int generation;
3087
3088 eb = path->nodes[0];
3089 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3090
3091 if (item_size >= sizeof(*ei) + sizeof(*bi)) {
3092 ei = btrfs_item_ptr(eb, path->slots[0],
3093 struct btrfs_extent_item);
3094 bi = (struct btrfs_tree_block_info *)(ei + 1);
3095 generation = btrfs_extent_generation(eb, ei);
3096 level = btrfs_tree_block_level(eb, bi);
3097 } else {
3098 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3099 u64 ref_owner;
3100 int ret;
3101
3102 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3103 ret = get_ref_objectid_v0(rc, path, extent_key,
3104 &ref_owner, NULL);
3105 if (ret < 0)
3106 return ret;
3107 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3108 level = (int)ref_owner;
3109 /* FIXME: get real generation */
3110 generation = 0;
3111 #else
3112 BUG();
3113 #endif
3114 }
3115
3116 btrfs_release_path(rc->extent_root, path);
3117
3118 BUG_ON(level == -1);
3119
3120 block = kmalloc(sizeof(*block), GFP_NOFS);
3121 if (!block)
3122 return -ENOMEM;
3123
3124 block->bytenr = extent_key->objectid;
3125 block->key.objectid = extent_key->offset;
3126 block->key.offset = generation;
3127 block->level = level;
3128 block->key_ready = 0;
3129
3130 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3131 BUG_ON(rb_node);
3132
3133 return 0;
3134 }
3135
3136 /*
3137 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3138 */
3139 static int __add_tree_block(struct reloc_control *rc,
3140 u64 bytenr, u32 blocksize,
3141 struct rb_root *blocks)
3142 {
3143 struct btrfs_path *path;
3144 struct btrfs_key key;
3145 int ret;
3146
3147 if (tree_block_processed(bytenr, blocksize, rc))
3148 return 0;
3149
3150 if (tree_search(blocks, bytenr))
3151 return 0;
3152
3153 path = btrfs_alloc_path();
3154 if (!path)
3155 return -ENOMEM;
3156
3157 key.objectid = bytenr;
3158 key.type = BTRFS_EXTENT_ITEM_KEY;
3159 key.offset = blocksize;
3160
3161 path->search_commit_root = 1;
3162 path->skip_locking = 1;
3163 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3164 if (ret < 0)
3165 goto out;
3166 BUG_ON(ret);
3167
3168 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3169 ret = add_tree_block(rc, &key, path, blocks);
3170 out:
3171 btrfs_free_path(path);
3172 return ret;
3173 }
3174
3175 /*
3176 * helper to check if the block use full backrefs for pointers in it
3177 */
3178 static int block_use_full_backref(struct reloc_control *rc,
3179 struct extent_buffer *eb)
3180 {
3181 u64 flags;
3182 int ret;
3183
3184 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3185 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3186 return 1;
3187
3188 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3189 eb->start, eb->len, NULL, &flags);
3190 BUG_ON(ret);
3191
3192 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3193 ret = 1;
3194 else
3195 ret = 0;
3196 return ret;
3197 }
3198
3199 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3200 struct inode *inode, u64 ino)
3201 {
3202 struct btrfs_key key;
3203 struct btrfs_path *path;
3204 struct btrfs_root *root = fs_info->tree_root;
3205 struct btrfs_trans_handle *trans;
3206 unsigned long nr;
3207 int ret = 0;
3208
3209 if (inode)
3210 goto truncate;
3211
3212 key.objectid = ino;
3213 key.type = BTRFS_INODE_ITEM_KEY;
3214 key.offset = 0;
3215
3216 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3217 if (!inode || IS_ERR(inode) || is_bad_inode(inode)) {
3218 if (inode && !IS_ERR(inode))
3219 iput(inode);
3220 return -ENOENT;
3221 }
3222
3223 truncate:
3224 path = btrfs_alloc_path();
3225 if (!path) {
3226 ret = -ENOMEM;
3227 goto out;
3228 }
3229
3230 trans = btrfs_join_transaction(root, 0);
3231 if (IS_ERR(trans)) {
3232 btrfs_free_path(path);
3233 ret = PTR_ERR(trans);
3234 goto out;
3235 }
3236
3237 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
3238
3239 btrfs_free_path(path);
3240 nr = trans->blocks_used;
3241 btrfs_end_transaction(trans, root);
3242 btrfs_btree_balance_dirty(root, nr);
3243 out:
3244 iput(inode);
3245 return ret;
3246 }
3247
3248 /*
3249 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3250 * this function scans fs tree to find blocks reference the data extent
3251 */
3252 static int find_data_references(struct reloc_control *rc,
3253 struct btrfs_key *extent_key,
3254 struct extent_buffer *leaf,
3255 struct btrfs_extent_data_ref *ref,
3256 struct rb_root *blocks)
3257 {
3258 struct btrfs_path *path;
3259 struct tree_block *block;
3260 struct btrfs_root *root;
3261 struct btrfs_file_extent_item *fi;
3262 struct rb_node *rb_node;
3263 struct btrfs_key key;
3264 u64 ref_root;
3265 u64 ref_objectid;
3266 u64 ref_offset;
3267 u32 ref_count;
3268 u32 nritems;
3269 int err = 0;
3270 int added = 0;
3271 int counted;
3272 int ret;
3273
3274 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3275 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3276 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3277 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3278
3279 /*
3280 * This is an extent belonging to the free space cache, lets just delete
3281 * it and redo the search.
3282 */
3283 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3284 ret = delete_block_group_cache(rc->extent_root->fs_info,
3285 NULL, ref_objectid);
3286 if (ret != -ENOENT)
3287 return ret;
3288 ret = 0;
3289 }
3290
3291 path = btrfs_alloc_path();
3292 if (!path)
3293 return -ENOMEM;
3294
3295 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3296 if (IS_ERR(root)) {
3297 err = PTR_ERR(root);
3298 goto out;
3299 }
3300
3301 key.objectid = ref_objectid;
3302 key.offset = ref_offset;
3303 key.type = BTRFS_EXTENT_DATA_KEY;
3304
3305 path->search_commit_root = 1;
3306 path->skip_locking = 1;
3307 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3308 if (ret < 0) {
3309 err = ret;
3310 goto out;
3311 }
3312
3313 leaf = path->nodes[0];
3314 nritems = btrfs_header_nritems(leaf);
3315 /*
3316 * the references in tree blocks that use full backrefs
3317 * are not counted in
3318 */
3319 if (block_use_full_backref(rc, leaf))
3320 counted = 0;
3321 else
3322 counted = 1;
3323 rb_node = tree_search(blocks, leaf->start);
3324 if (rb_node) {
3325 if (counted)
3326 added = 1;
3327 else
3328 path->slots[0] = nritems;
3329 }
3330
3331 while (ref_count > 0) {
3332 while (path->slots[0] >= nritems) {
3333 ret = btrfs_next_leaf(root, path);
3334 if (ret < 0) {
3335 err = ret;
3336 goto out;
3337 }
3338 if (ret > 0) {
3339 WARN_ON(1);
3340 goto out;
3341 }
3342
3343 leaf = path->nodes[0];
3344 nritems = btrfs_header_nritems(leaf);
3345 added = 0;
3346
3347 if (block_use_full_backref(rc, leaf))
3348 counted = 0;
3349 else
3350 counted = 1;
3351 rb_node = tree_search(blocks, leaf->start);
3352 if (rb_node) {
3353 if (counted)
3354 added = 1;
3355 else
3356 path->slots[0] = nritems;
3357 }
3358 }
3359
3360 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3361 if (key.objectid != ref_objectid ||
3362 key.type != BTRFS_EXTENT_DATA_KEY) {
3363 WARN_ON(1);
3364 break;
3365 }
3366
3367 fi = btrfs_item_ptr(leaf, path->slots[0],
3368 struct btrfs_file_extent_item);
3369
3370 if (btrfs_file_extent_type(leaf, fi) ==
3371 BTRFS_FILE_EXTENT_INLINE)
3372 goto next;
3373
3374 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3375 extent_key->objectid)
3376 goto next;
3377
3378 key.offset -= btrfs_file_extent_offset(leaf, fi);
3379 if (key.offset != ref_offset)
3380 goto next;
3381
3382 if (counted)
3383 ref_count--;
3384 if (added)
3385 goto next;
3386
3387 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3388 block = kmalloc(sizeof(*block), GFP_NOFS);
3389 if (!block) {
3390 err = -ENOMEM;
3391 break;
3392 }
3393 block->bytenr = leaf->start;
3394 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3395 block->level = 0;
3396 block->key_ready = 1;
3397 rb_node = tree_insert(blocks, block->bytenr,
3398 &block->rb_node);
3399 BUG_ON(rb_node);
3400 }
3401 if (counted)
3402 added = 1;
3403 else
3404 path->slots[0] = nritems;
3405 next:
3406 path->slots[0]++;
3407
3408 }
3409 out:
3410 btrfs_free_path(path);
3411 return err;
3412 }
3413
3414 /*
3415 * hepler to find all tree blocks that reference a given data extent
3416 */
3417 static noinline_for_stack
3418 int add_data_references(struct reloc_control *rc,
3419 struct btrfs_key *extent_key,
3420 struct btrfs_path *path,
3421 struct rb_root *blocks)
3422 {
3423 struct btrfs_key key;
3424 struct extent_buffer *eb;
3425 struct btrfs_extent_data_ref *dref;
3426 struct btrfs_extent_inline_ref *iref;
3427 unsigned long ptr;
3428 unsigned long end;
3429 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3430 int ret;
3431 int err = 0;
3432
3433 eb = path->nodes[0];
3434 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3435 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3436 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3437 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3438 ptr = end;
3439 else
3440 #endif
3441 ptr += sizeof(struct btrfs_extent_item);
3442
3443 while (ptr < end) {
3444 iref = (struct btrfs_extent_inline_ref *)ptr;
3445 key.type = btrfs_extent_inline_ref_type(eb, iref);
3446 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3447 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3448 ret = __add_tree_block(rc, key.offset, blocksize,
3449 blocks);
3450 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3451 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3452 ret = find_data_references(rc, extent_key,
3453 eb, dref, blocks);
3454 } else {
3455 BUG();
3456 }
3457 ptr += btrfs_extent_inline_ref_size(key.type);
3458 }
3459 WARN_ON(ptr > end);
3460
3461 while (1) {
3462 cond_resched();
3463 eb = path->nodes[0];
3464 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3465 ret = btrfs_next_leaf(rc->extent_root, path);
3466 if (ret < 0) {
3467 err = ret;
3468 break;
3469 }
3470 if (ret > 0)
3471 break;
3472 eb = path->nodes[0];
3473 }
3474
3475 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3476 if (key.objectid != extent_key->objectid)
3477 break;
3478
3479 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3480 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3481 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3482 #else
3483 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3484 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3485 #endif
3486 ret = __add_tree_block(rc, key.offset, blocksize,
3487 blocks);
3488 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3489 dref = btrfs_item_ptr(eb, path->slots[0],
3490 struct btrfs_extent_data_ref);
3491 ret = find_data_references(rc, extent_key,
3492 eb, dref, blocks);
3493 } else {
3494 ret = 0;
3495 }
3496 if (ret) {
3497 err = ret;
3498 break;
3499 }
3500 path->slots[0]++;
3501 }
3502 btrfs_release_path(rc->extent_root, path);
3503 if (err)
3504 free_block_list(blocks);
3505 return err;
3506 }
3507
3508 /*
3509 * hepler to find next unprocessed extent
3510 */
3511 static noinline_for_stack
3512 int find_next_extent(struct btrfs_trans_handle *trans,
3513 struct reloc_control *rc, struct btrfs_path *path,
3514 struct btrfs_key *extent_key)
3515 {
3516 struct btrfs_key key;
3517 struct extent_buffer *leaf;
3518 u64 start, end, last;
3519 int ret;
3520
3521 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3522 while (1) {
3523 cond_resched();
3524 if (rc->search_start >= last) {
3525 ret = 1;
3526 break;
3527 }
3528
3529 key.objectid = rc->search_start;
3530 key.type = BTRFS_EXTENT_ITEM_KEY;
3531 key.offset = 0;
3532
3533 path->search_commit_root = 1;
3534 path->skip_locking = 1;
3535 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3536 0, 0);
3537 if (ret < 0)
3538 break;
3539 next:
3540 leaf = path->nodes[0];
3541 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3542 ret = btrfs_next_leaf(rc->extent_root, path);
3543 if (ret != 0)
3544 break;
3545 leaf = path->nodes[0];
3546 }
3547
3548 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3549 if (key.objectid >= last) {
3550 ret = 1;
3551 break;
3552 }
3553
3554 if (key.type != BTRFS_EXTENT_ITEM_KEY ||
3555 key.objectid + key.offset <= rc->search_start) {
3556 path->slots[0]++;
3557 goto next;
3558 }
3559
3560 ret = find_first_extent_bit(&rc->processed_blocks,
3561 key.objectid, &start, &end,
3562 EXTENT_DIRTY);
3563
3564 if (ret == 0 && start <= key.objectid) {
3565 btrfs_release_path(rc->extent_root, path);
3566 rc->search_start = end + 1;
3567 } else {
3568 rc->search_start = key.objectid + key.offset;
3569 memcpy(extent_key, &key, sizeof(key));
3570 return 0;
3571 }
3572 }
3573 btrfs_release_path(rc->extent_root, path);
3574 return ret;
3575 }
3576
3577 static void set_reloc_control(struct reloc_control *rc)
3578 {
3579 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3580 mutex_lock(&fs_info->trans_mutex);
3581 fs_info->reloc_ctl = rc;
3582 mutex_unlock(&fs_info->trans_mutex);
3583 }
3584
3585 static void unset_reloc_control(struct reloc_control *rc)
3586 {
3587 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3588 mutex_lock(&fs_info->trans_mutex);
3589 fs_info->reloc_ctl = NULL;
3590 mutex_unlock(&fs_info->trans_mutex);
3591 }
3592
3593 static int check_extent_flags(u64 flags)
3594 {
3595 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3596 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3597 return 1;
3598 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3599 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3600 return 1;
3601 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3602 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3603 return 1;
3604 return 0;
3605 }
3606
3607 static noinline_for_stack
3608 int prepare_to_relocate(struct reloc_control *rc)
3609 {
3610 struct btrfs_trans_handle *trans;
3611 int ret;
3612
3613 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root);
3614 if (!rc->block_rsv)
3615 return -ENOMEM;
3616
3617 /*
3618 * reserve some space for creating reloc trees.
3619 * btrfs_init_reloc_root will use them when there
3620 * is no reservation in transaction handle.
3621 */
3622 ret = btrfs_block_rsv_add(NULL, rc->extent_root, rc->block_rsv,
3623 rc->extent_root->nodesize * 256);
3624 if (ret)
3625 return ret;
3626
3627 rc->block_rsv->refill_used = 1;
3628 btrfs_add_durable_block_rsv(rc->extent_root->fs_info, rc->block_rsv);
3629
3630 memset(&rc->cluster, 0, sizeof(rc->cluster));
3631 rc->search_start = rc->block_group->key.objectid;
3632 rc->extents_found = 0;
3633 rc->nodes_relocated = 0;
3634 rc->merging_rsv_size = 0;
3635
3636 rc->create_reloc_tree = 1;
3637 set_reloc_control(rc);
3638
3639 trans = btrfs_join_transaction(rc->extent_root, 1);
3640 BUG_ON(IS_ERR(trans));
3641 btrfs_commit_transaction(trans, rc->extent_root);
3642 return 0;
3643 }
3644
3645 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3646 {
3647 struct rb_root blocks = RB_ROOT;
3648 struct btrfs_key key;
3649 struct btrfs_trans_handle *trans = NULL;
3650 struct btrfs_path *path;
3651 struct btrfs_extent_item *ei;
3652 unsigned long nr;
3653 u64 flags;
3654 u32 item_size;
3655 int ret;
3656 int err = 0;
3657 int progress = 0;
3658
3659 path = btrfs_alloc_path();
3660 if (!path)
3661 return -ENOMEM;
3662
3663 ret = prepare_to_relocate(rc);
3664 if (ret) {
3665 err = ret;
3666 goto out_free;
3667 }
3668
3669 while (1) {
3670 progress++;
3671 trans = btrfs_start_transaction(rc->extent_root, 0);
3672 BUG_ON(IS_ERR(trans));
3673 restart:
3674 if (update_backref_cache(trans, &rc->backref_cache)) {
3675 btrfs_end_transaction(trans, rc->extent_root);
3676 continue;
3677 }
3678
3679 ret = find_next_extent(trans, rc, path, &key);
3680 if (ret < 0)
3681 err = ret;
3682 if (ret != 0)
3683 break;
3684
3685 rc->extents_found++;
3686
3687 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3688 struct btrfs_extent_item);
3689 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3690 if (item_size >= sizeof(*ei)) {
3691 flags = btrfs_extent_flags(path->nodes[0], ei);
3692 ret = check_extent_flags(flags);
3693 BUG_ON(ret);
3694
3695 } else {
3696 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3697 u64 ref_owner;
3698 int path_change = 0;
3699
3700 BUG_ON(item_size !=
3701 sizeof(struct btrfs_extent_item_v0));
3702 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3703 &path_change);
3704 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3705 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3706 else
3707 flags = BTRFS_EXTENT_FLAG_DATA;
3708
3709 if (path_change) {
3710 btrfs_release_path(rc->extent_root, path);
3711
3712 path->search_commit_root = 1;
3713 path->skip_locking = 1;
3714 ret = btrfs_search_slot(NULL, rc->extent_root,
3715 &key, path, 0, 0);
3716 if (ret < 0) {
3717 err = ret;
3718 break;
3719 }
3720 BUG_ON(ret > 0);
3721 }
3722 #else
3723 BUG();
3724 #endif
3725 }
3726
3727 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3728 ret = add_tree_block(rc, &key, path, &blocks);
3729 } else if (rc->stage == UPDATE_DATA_PTRS &&
3730 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3731 ret = add_data_references(rc, &key, path, &blocks);
3732 } else {
3733 btrfs_release_path(rc->extent_root, path);
3734 ret = 0;
3735 }
3736 if (ret < 0) {
3737 err = ret;
3738 break;
3739 }
3740
3741 if (!RB_EMPTY_ROOT(&blocks)) {
3742 ret = relocate_tree_blocks(trans, rc, &blocks);
3743 if (ret < 0) {
3744 if (ret != -EAGAIN) {
3745 err = ret;
3746 break;
3747 }
3748 rc->extents_found--;
3749 rc->search_start = key.objectid;
3750 }
3751 }
3752
3753 ret = btrfs_block_rsv_check(trans, rc->extent_root,
3754 rc->block_rsv, 0, 5);
3755 if (ret < 0) {
3756 if (ret != -EAGAIN) {
3757 err = ret;
3758 WARN_ON(1);
3759 break;
3760 }
3761 rc->commit_transaction = 1;
3762 }
3763
3764 if (rc->commit_transaction) {
3765 rc->commit_transaction = 0;
3766 ret = btrfs_commit_transaction(trans, rc->extent_root);
3767 BUG_ON(ret);
3768 } else {
3769 nr = trans->blocks_used;
3770 btrfs_end_transaction_throttle(trans, rc->extent_root);
3771 btrfs_btree_balance_dirty(rc->extent_root, nr);
3772 }
3773 trans = NULL;
3774
3775 if (rc->stage == MOVE_DATA_EXTENTS &&
3776 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3777 rc->found_file_extent = 1;
3778 ret = relocate_data_extent(rc->data_inode,
3779 &key, &rc->cluster);
3780 if (ret < 0) {
3781 err = ret;
3782 break;
3783 }
3784 }
3785 }
3786 if (trans && progress && err == -ENOSPC) {
3787 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
3788 rc->block_group->flags);
3789 if (ret == 0) {
3790 err = 0;
3791 progress = 0;
3792 goto restart;
3793 }
3794 }
3795
3796 btrfs_release_path(rc->extent_root, path);
3797 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3798 GFP_NOFS);
3799
3800 if (trans) {
3801 nr = trans->blocks_used;
3802 btrfs_end_transaction_throttle(trans, rc->extent_root);
3803 btrfs_btree_balance_dirty(rc->extent_root, nr);
3804 }
3805
3806 if (!err) {
3807 ret = relocate_file_extent_cluster(rc->data_inode,
3808 &rc->cluster);
3809 if (ret < 0)
3810 err = ret;
3811 }
3812
3813 rc->create_reloc_tree = 0;
3814 set_reloc_control(rc);
3815
3816 backref_cache_cleanup(&rc->backref_cache);
3817 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3818
3819 err = prepare_to_merge(rc, err);
3820
3821 merge_reloc_roots(rc);
3822
3823 rc->merge_reloc_tree = 0;
3824 unset_reloc_control(rc);
3825 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3826
3827 /* get rid of pinned extents */
3828 trans = btrfs_join_transaction(rc->extent_root, 1);
3829 if (IS_ERR(trans))
3830 err = PTR_ERR(trans);
3831 else
3832 btrfs_commit_transaction(trans, rc->extent_root);
3833 out_free:
3834 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
3835 btrfs_free_path(path);
3836 return err;
3837 }
3838
3839 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3840 struct btrfs_root *root, u64 objectid)
3841 {
3842 struct btrfs_path *path;
3843 struct btrfs_inode_item *item;
3844 struct extent_buffer *leaf;
3845 int ret;
3846
3847 path = btrfs_alloc_path();
3848 if (!path)
3849 return -ENOMEM;
3850
3851 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3852 if (ret)
3853 goto out;
3854
3855 leaf = path->nodes[0];
3856 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3857 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
3858 btrfs_set_inode_generation(leaf, item, 1);
3859 btrfs_set_inode_size(leaf, item, 0);
3860 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3861 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3862 BTRFS_INODE_PREALLOC);
3863 btrfs_mark_buffer_dirty(leaf);
3864 btrfs_release_path(root, path);
3865 out:
3866 btrfs_free_path(path);
3867 return ret;
3868 }
3869
3870 /*
3871 * helper to create inode for data relocation.
3872 * the inode is in data relocation tree and its link count is 0
3873 */
3874 static noinline_for_stack
3875 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3876 struct btrfs_block_group_cache *group)
3877 {
3878 struct inode *inode = NULL;
3879 struct btrfs_trans_handle *trans;
3880 struct btrfs_root *root;
3881 struct btrfs_key key;
3882 unsigned long nr;
3883 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
3884 int err = 0;
3885
3886 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
3887 if (IS_ERR(root))
3888 return ERR_CAST(root);
3889
3890 trans = btrfs_start_transaction(root, 6);
3891 if (IS_ERR(trans))
3892 return ERR_CAST(trans);
3893
3894 err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
3895 if (err)
3896 goto out;
3897
3898 err = __insert_orphan_inode(trans, root, objectid);
3899 BUG_ON(err);
3900
3901 key.objectid = objectid;
3902 key.type = BTRFS_INODE_ITEM_KEY;
3903 key.offset = 0;
3904 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
3905 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
3906 BTRFS_I(inode)->index_cnt = group->key.objectid;
3907
3908 err = btrfs_orphan_add(trans, inode);
3909 out:
3910 nr = trans->blocks_used;
3911 btrfs_end_transaction(trans, root);
3912 btrfs_btree_balance_dirty(root, nr);
3913 if (err) {
3914 if (inode)
3915 iput(inode);
3916 inode = ERR_PTR(err);
3917 }
3918 return inode;
3919 }
3920
3921 static struct reloc_control *alloc_reloc_control(void)
3922 {
3923 struct reloc_control *rc;
3924
3925 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3926 if (!rc)
3927 return NULL;
3928
3929 INIT_LIST_HEAD(&rc->reloc_roots);
3930 backref_cache_init(&rc->backref_cache);
3931 mapping_tree_init(&rc->reloc_root_tree);
3932 extent_io_tree_init(&rc->processed_blocks, NULL, GFP_NOFS);
3933 return rc;
3934 }
3935
3936 /*
3937 * function to relocate all extents in a block group.
3938 */
3939 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
3940 {
3941 struct btrfs_fs_info *fs_info = extent_root->fs_info;
3942 struct reloc_control *rc;
3943 struct inode *inode;
3944 struct btrfs_path *path;
3945 int ret;
3946 int rw = 0;
3947 int err = 0;
3948
3949 rc = alloc_reloc_control();
3950 if (!rc)
3951 return -ENOMEM;
3952
3953 rc->extent_root = extent_root;
3954
3955 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
3956 BUG_ON(!rc->block_group);
3957
3958 if (!rc->block_group->ro) {
3959 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
3960 if (ret) {
3961 err = ret;
3962 goto out;
3963 }
3964 rw = 1;
3965 }
3966
3967 path = btrfs_alloc_path();
3968 if (!path) {
3969 err = -ENOMEM;
3970 goto out;
3971 }
3972
3973 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
3974 path);
3975 btrfs_free_path(path);
3976
3977 if (!IS_ERR(inode))
3978 ret = delete_block_group_cache(fs_info, inode, 0);
3979 else
3980 ret = PTR_ERR(inode);
3981
3982 if (ret && ret != -ENOENT) {
3983 err = ret;
3984 goto out;
3985 }
3986
3987 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
3988 if (IS_ERR(rc->data_inode)) {
3989 err = PTR_ERR(rc->data_inode);
3990 rc->data_inode = NULL;
3991 goto out;
3992 }
3993
3994 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
3995 (unsigned long long)rc->block_group->key.objectid,
3996 (unsigned long long)rc->block_group->flags);
3997
3998 btrfs_start_delalloc_inodes(fs_info->tree_root, 0);
3999 btrfs_wait_ordered_extents(fs_info->tree_root, 0, 0);
4000
4001 while (1) {
4002 mutex_lock(&fs_info->cleaner_mutex);
4003
4004 btrfs_clean_old_snapshots(fs_info->tree_root);
4005 ret = relocate_block_group(rc);
4006
4007 mutex_unlock(&fs_info->cleaner_mutex);
4008 if (ret < 0) {
4009 err = ret;
4010 goto out;
4011 }
4012
4013 if (rc->extents_found == 0)
4014 break;
4015
4016 printk(KERN_INFO "btrfs: found %llu extents\n",
4017 (unsigned long long)rc->extents_found);
4018
4019 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4020 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
4021 invalidate_mapping_pages(rc->data_inode->i_mapping,
4022 0, -1);
4023 rc->stage = UPDATE_DATA_PTRS;
4024 }
4025 }
4026
4027 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
4028 rc->block_group->key.objectid,
4029 rc->block_group->key.objectid +
4030 rc->block_group->key.offset - 1);
4031
4032 WARN_ON(rc->block_group->pinned > 0);
4033 WARN_ON(rc->block_group->reserved > 0);
4034 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4035 out:
4036 if (err && rw)
4037 btrfs_set_block_group_rw(extent_root, rc->block_group);
4038 iput(rc->data_inode);
4039 btrfs_put_block_group(rc->block_group);
4040 kfree(rc);
4041 return err;
4042 }
4043
4044 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4045 {
4046 struct btrfs_trans_handle *trans;
4047 int ret;
4048
4049 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4050 BUG_ON(IS_ERR(trans));
4051
4052 memset(&root->root_item.drop_progress, 0,
4053 sizeof(root->root_item.drop_progress));
4054 root->root_item.drop_level = 0;
4055 btrfs_set_root_refs(&root->root_item, 0);
4056 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4057 &root->root_key, &root->root_item);
4058 BUG_ON(ret);
4059
4060 ret = btrfs_end_transaction(trans, root->fs_info->tree_root);
4061 BUG_ON(ret);
4062 return 0;
4063 }
4064
4065 /*
4066 * recover relocation interrupted by system crash.
4067 *
4068 * this function resumes merging reloc trees with corresponding fs trees.
4069 * this is important for keeping the sharing of tree blocks
4070 */
4071 int btrfs_recover_relocation(struct btrfs_root *root)
4072 {
4073 LIST_HEAD(reloc_roots);
4074 struct btrfs_key key;
4075 struct btrfs_root *fs_root;
4076 struct btrfs_root *reloc_root;
4077 struct btrfs_path *path;
4078 struct extent_buffer *leaf;
4079 struct reloc_control *rc = NULL;
4080 struct btrfs_trans_handle *trans;
4081 int ret;
4082 int err = 0;
4083
4084 path = btrfs_alloc_path();
4085 if (!path)
4086 return -ENOMEM;
4087
4088 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4089 key.type = BTRFS_ROOT_ITEM_KEY;
4090 key.offset = (u64)-1;
4091
4092 while (1) {
4093 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4094 path, 0, 0);
4095 if (ret < 0) {
4096 err = ret;
4097 goto out;
4098 }
4099 if (ret > 0) {
4100 if (path->slots[0] == 0)
4101 break;
4102 path->slots[0]--;
4103 }
4104 leaf = path->nodes[0];
4105 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4106 btrfs_release_path(root->fs_info->tree_root, path);
4107
4108 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4109 key.type != BTRFS_ROOT_ITEM_KEY)
4110 break;
4111
4112 reloc_root = btrfs_read_fs_root_no_radix(root, &key);
4113 if (IS_ERR(reloc_root)) {
4114 err = PTR_ERR(reloc_root);
4115 goto out;
4116 }
4117
4118 list_add(&reloc_root->root_list, &reloc_roots);
4119
4120 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4121 fs_root = read_fs_root(root->fs_info,
4122 reloc_root->root_key.offset);
4123 if (IS_ERR(fs_root)) {
4124 ret = PTR_ERR(fs_root);
4125 if (ret != -ENOENT) {
4126 err = ret;
4127 goto out;
4128 }
4129 mark_garbage_root(reloc_root);
4130 }
4131 }
4132
4133 if (key.offset == 0)
4134 break;
4135
4136 key.offset--;
4137 }
4138 btrfs_release_path(root->fs_info->tree_root, path);
4139
4140 if (list_empty(&reloc_roots))
4141 goto out;
4142
4143 rc = alloc_reloc_control();
4144 if (!rc) {
4145 err = -ENOMEM;
4146 goto out;
4147 }
4148
4149 rc->extent_root = root->fs_info->extent_root;
4150
4151 set_reloc_control(rc);
4152
4153 trans = btrfs_join_transaction(rc->extent_root, 1);
4154 if (IS_ERR(trans)) {
4155 unset_reloc_control(rc);
4156 err = PTR_ERR(trans);
4157 goto out_free;
4158 }
4159
4160 rc->merge_reloc_tree = 1;
4161
4162 while (!list_empty(&reloc_roots)) {
4163 reloc_root = list_entry(reloc_roots.next,
4164 struct btrfs_root, root_list);
4165 list_del(&reloc_root->root_list);
4166
4167 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4168 list_add_tail(&reloc_root->root_list,
4169 &rc->reloc_roots);
4170 continue;
4171 }
4172
4173 fs_root = read_fs_root(root->fs_info,
4174 reloc_root->root_key.offset);
4175 BUG_ON(IS_ERR(fs_root));
4176
4177 __add_reloc_root(reloc_root);
4178 fs_root->reloc_root = reloc_root;
4179 }
4180
4181 btrfs_commit_transaction(trans, rc->extent_root);
4182
4183 merge_reloc_roots(rc);
4184
4185 unset_reloc_control(rc);
4186
4187 trans = btrfs_join_transaction(rc->extent_root, 1);
4188 if (IS_ERR(trans))
4189 err = PTR_ERR(trans);
4190 else
4191 btrfs_commit_transaction(trans, rc->extent_root);
4192 out_free:
4193 kfree(rc);
4194 out:
4195 while (!list_empty(&reloc_roots)) {
4196 reloc_root = list_entry(reloc_roots.next,
4197 struct btrfs_root, root_list);
4198 list_del(&reloc_root->root_list);
4199 free_extent_buffer(reloc_root->node);
4200 free_extent_buffer(reloc_root->commit_root);
4201 kfree(reloc_root);
4202 }
4203 btrfs_free_path(path);
4204
4205 if (err == 0) {
4206 /* cleanup orphan inode in data relocation tree */
4207 fs_root = read_fs_root(root->fs_info,
4208 BTRFS_DATA_RELOC_TREE_OBJECTID);
4209 if (IS_ERR(fs_root))
4210 err = PTR_ERR(fs_root);
4211 else
4212 btrfs_orphan_cleanup(fs_root);
4213 }
4214 return err;
4215 }
4216
4217 /*
4218 * helper to add ordered checksum for data relocation.
4219 *
4220 * cloning checksum properly handles the nodatasum extents.
4221 * it also saves CPU time to re-calculate the checksum.
4222 */
4223 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4224 {
4225 struct btrfs_ordered_sum *sums;
4226 struct btrfs_sector_sum *sector_sum;
4227 struct btrfs_ordered_extent *ordered;
4228 struct btrfs_root *root = BTRFS_I(inode)->root;
4229 size_t offset;
4230 int ret;
4231 u64 disk_bytenr;
4232 LIST_HEAD(list);
4233
4234 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4235 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4236
4237 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4238 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4239 disk_bytenr + len - 1, &list);
4240
4241 while (!list_empty(&list)) {
4242 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4243 list_del_init(&sums->list);
4244
4245 sector_sum = sums->sums;
4246 sums->bytenr = ordered->start;
4247
4248 offset = 0;
4249 while (offset < sums->len) {
4250 sector_sum->bytenr += ordered->start - disk_bytenr;
4251 sector_sum++;
4252 offset += root->sectorsize;
4253 }
4254
4255 btrfs_add_ordered_sum(inode, ordered, sums);
4256 }
4257 btrfs_put_ordered_extent(ordered);
4258 return ret;
4259 }
4260
4261 void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4262 struct btrfs_root *root, struct extent_buffer *buf,
4263 struct extent_buffer *cow)
4264 {
4265 struct reloc_control *rc;
4266 struct backref_node *node;
4267 int first_cow = 0;
4268 int level;
4269 int ret;
4270
4271 rc = root->fs_info->reloc_ctl;
4272 if (!rc)
4273 return;
4274
4275 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4276 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4277
4278 level = btrfs_header_level(buf);
4279 if (btrfs_header_generation(buf) <=
4280 btrfs_root_last_snapshot(&root->root_item))
4281 first_cow = 1;
4282
4283 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4284 rc->create_reloc_tree) {
4285 WARN_ON(!first_cow && level == 0);
4286
4287 node = rc->backref_cache.path[level];
4288 BUG_ON(node->bytenr != buf->start &&
4289 node->new_bytenr != buf->start);
4290
4291 drop_node_buffer(node);
4292 extent_buffer_get(cow);
4293 node->eb = cow;
4294 node->new_bytenr = cow->start;
4295
4296 if (!node->pending) {
4297 list_move_tail(&node->list,
4298 &rc->backref_cache.pending[level]);
4299 node->pending = 1;
4300 }
4301
4302 if (first_cow)
4303 __mark_block_processed(rc, node);
4304
4305 if (first_cow && level > 0)
4306 rc->nodes_relocated += buf->len;
4307 }
4308
4309 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) {
4310 ret = replace_file_extents(trans, rc, root, cow);
4311 BUG_ON(ret);
4312 }
4313 }
4314
4315 /*
4316 * called before creating snapshot. it calculates metadata reservation
4317 * requried for relocating tree blocks in the snapshot
4318 */
4319 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4320 struct btrfs_pending_snapshot *pending,
4321 u64 *bytes_to_reserve)
4322 {
4323 struct btrfs_root *root;
4324 struct reloc_control *rc;
4325
4326 root = pending->root;
4327 if (!root->reloc_root)
4328 return;
4329
4330 rc = root->fs_info->reloc_ctl;
4331 if (!rc->merge_reloc_tree)
4332 return;
4333
4334 root = root->reloc_root;
4335 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4336 /*
4337 * relocation is in the stage of merging trees. the space
4338 * used by merging a reloc tree is twice the size of
4339 * relocated tree nodes in the worst case. half for cowing
4340 * the reloc tree, half for cowing the fs tree. the space
4341 * used by cowing the reloc tree will be freed after the
4342 * tree is dropped. if we create snapshot, cowing the fs
4343 * tree may use more space than it frees. so we need
4344 * reserve extra space.
4345 */
4346 *bytes_to_reserve += rc->nodes_relocated;
4347 }
4348
4349 /*
4350 * called after snapshot is created. migrate block reservation
4351 * and create reloc root for the newly created snapshot
4352 */
4353 void btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4354 struct btrfs_pending_snapshot *pending)
4355 {
4356 struct btrfs_root *root = pending->root;
4357 struct btrfs_root *reloc_root;
4358 struct btrfs_root *new_root;
4359 struct reloc_control *rc;
4360 int ret;
4361
4362 if (!root->reloc_root)
4363 return;
4364
4365 rc = root->fs_info->reloc_ctl;
4366 rc->merging_rsv_size += rc->nodes_relocated;
4367
4368 if (rc->merge_reloc_tree) {
4369 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4370 rc->block_rsv,
4371 rc->nodes_relocated);
4372 BUG_ON(ret);
4373 }
4374
4375 new_root = pending->snap;
4376 reloc_root = create_reloc_root(trans, root->reloc_root,
4377 new_root->root_key.objectid);
4378
4379 __add_reloc_root(reloc_root);
4380 new_root->reloc_root = reloc_root;
4381
4382 if (rc->create_reloc_tree) {
4383 ret = clone_backref_node(trans, rc, root, reloc_root);
4384 BUG_ON(ret);
4385 }
4386 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree