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Btrfs: Cache free inode numbers in memory
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / btrfs / relocation.c
blobe6cb8935725607636d79fd797ac00a02ada1517d
1 /*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33 #include "inode-map.h"
34
35 /*
36 * backref_node, mapping_node and tree_block start with this
37 */
38 struct tree_entry {
39 struct rb_node rb_node;
40 u64 bytenr;
41 };
42
43 /*
44 * present a tree block in the backref cache
45 */
46 struct backref_node {
47 struct rb_node rb_node;
48 u64 bytenr;
49
50 u64 new_bytenr;
51 /* objectid of tree block owner, can be not uptodate */
52 u64 owner;
53 /* link to pending, changed or detached list */
54 struct list_head list;
55 /* list of upper level blocks reference this block */
56 struct list_head upper;
57 /* list of child blocks in the cache */
58 struct list_head lower;
59 /* NULL if this node is not tree root */
60 struct btrfs_root *root;
61 /* extent buffer got by COW the block */
62 struct extent_buffer *eb;
63 /* level of tree block */
64 unsigned int level:8;
65 /* is the block in non-reference counted tree */
66 unsigned int cowonly:1;
67 /* 1 if no child node in the cache */
68 unsigned int lowest:1;
69 /* is the extent buffer locked */
70 unsigned int locked:1;
71 /* has the block been processed */
72 unsigned int processed:1;
73 /* have backrefs of this block been checked */
74 unsigned int checked:1;
75 /*
76 * 1 if corresponding block has been cowed but some upper
77 * level block pointers may not point to the new location
78 */
79 unsigned int pending:1;
80 /*
81 * 1 if the backref node isn't connected to any other
82 * backref node.
83 */
84 unsigned int detached:1;
85 };
86
87 /*
88 * present a block pointer in the backref cache
89 */
90 struct backref_edge {
91 struct list_head list[2];
92 struct backref_node *node[2];
93 };
94
95 #define LOWER 0
96 #define UPPER 1
97
98 struct backref_cache {
99 /* red black tree of all backref nodes in the cache */
100 struct rb_root rb_root;
101 /* for passing backref nodes to btrfs_reloc_cow_block */
102 struct backref_node *path[BTRFS_MAX_LEVEL];
103 /*
104 * list of blocks that have been cowed but some block
105 * pointers in upper level blocks may not reflect the
106 * new location
107 */
108 struct list_head pending[BTRFS_MAX_LEVEL];
109 /* list of backref nodes with no child node */
110 struct list_head leaves;
111 /* list of blocks that have been cowed in current transaction */
112 struct list_head changed;
113 /* list of detached backref node. */
114 struct list_head detached;
115
116 u64 last_trans;
117
118 int nr_nodes;
119 int nr_edges;
120 };
121
122 /*
123 * map address of tree root to tree
124 */
125 struct mapping_node {
126 struct rb_node rb_node;
127 u64 bytenr;
128 void *data;
129 };
130
131 struct mapping_tree {
132 struct rb_root rb_root;
133 spinlock_t lock;
134 };
135
136 /*
137 * present a tree block to process
138 */
139 struct tree_block {
140 struct rb_node rb_node;
141 u64 bytenr;
142 struct btrfs_key key;
143 unsigned int level:8;
144 unsigned int key_ready:1;
145 };
146
147 #define MAX_EXTENTS 128
148
149 struct file_extent_cluster {
150 u64 start;
151 u64 end;
152 u64 boundary[MAX_EXTENTS];
153 unsigned int nr;
154 };
155
156 struct reloc_control {
157 /* block group to relocate */
158 struct btrfs_block_group_cache *block_group;
159 /* extent tree */
160 struct btrfs_root *extent_root;
161 /* inode for moving data */
162 struct inode *data_inode;
163
164 struct btrfs_block_rsv *block_rsv;
165
166 struct backref_cache backref_cache;
167
168 struct file_extent_cluster cluster;
169 /* tree blocks have been processed */
170 struct extent_io_tree processed_blocks;
171 /* map start of tree root to corresponding reloc tree */
172 struct mapping_tree reloc_root_tree;
173 /* list of reloc trees */
174 struct list_head reloc_roots;
175 /* size of metadata reservation for merging reloc trees */
176 u64 merging_rsv_size;
177 /* size of relocated tree nodes */
178 u64 nodes_relocated;
179
180 u64 search_start;
181 u64 extents_found;
182
183 unsigned int stage:8;
184 unsigned int create_reloc_tree:1;
185 unsigned int merge_reloc_tree:1;
186 unsigned int found_file_extent:1;
187 unsigned int commit_transaction:1;
188 };
189
190 /* stages of data relocation */
191 #define MOVE_DATA_EXTENTS 0
192 #define UPDATE_DATA_PTRS 1
193
194 static void remove_backref_node(struct backref_cache *cache,
195 struct backref_node *node);
196 static void __mark_block_processed(struct reloc_control *rc,
197 struct backref_node *node);
198
199 static void mapping_tree_init(struct mapping_tree *tree)
200 {
201 tree->rb_root = RB_ROOT;
202 spin_lock_init(&tree->lock);
203 }
204
205 static void backref_cache_init(struct backref_cache *cache)
206 {
207 int i;
208 cache->rb_root = RB_ROOT;
209 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
210 INIT_LIST_HEAD(&cache->pending[i]);
211 INIT_LIST_HEAD(&cache->changed);
212 INIT_LIST_HEAD(&cache->detached);
213 INIT_LIST_HEAD(&cache->leaves);
214 }
215
216 static void backref_cache_cleanup(struct backref_cache *cache)
217 {
218 struct backref_node *node;
219 int i;
220
221 while (!list_empty(&cache->detached)) {
222 node = list_entry(cache->detached.next,
223 struct backref_node, list);
224 remove_backref_node(cache, node);
225 }
226
227 while (!list_empty(&cache->leaves)) {
228 node = list_entry(cache->leaves.next,
229 struct backref_node, lower);
230 remove_backref_node(cache, node);
231 }
232
233 cache->last_trans = 0;
234
235 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
236 BUG_ON(!list_empty(&cache->pending[i]));
237 BUG_ON(!list_empty(&cache->changed));
238 BUG_ON(!list_empty(&cache->detached));
239 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
240 BUG_ON(cache->nr_nodes);
241 BUG_ON(cache->nr_edges);
242 }
243
244 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
245 {
246 struct backref_node *node;
247
248 node = kzalloc(sizeof(*node), GFP_NOFS);
249 if (node) {
250 INIT_LIST_HEAD(&node->list);
251 INIT_LIST_HEAD(&node->upper);
252 INIT_LIST_HEAD(&node->lower);
253 RB_CLEAR_NODE(&node->rb_node);
254 cache->nr_nodes++;
255 }
256 return node;
257 }
258
259 static void free_backref_node(struct backref_cache *cache,
260 struct backref_node *node)
261 {
262 if (node) {
263 cache->nr_nodes--;
264 kfree(node);
265 }
266 }
267
268 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
269 {
270 struct backref_edge *edge;
271
272 edge = kzalloc(sizeof(*edge), GFP_NOFS);
273 if (edge)
274 cache->nr_edges++;
275 return edge;
276 }
277
278 static void free_backref_edge(struct backref_cache *cache,
279 struct backref_edge *edge)
280 {
281 if (edge) {
282 cache->nr_edges--;
283 kfree(edge);
284 }
285 }
286
287 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
288 struct rb_node *node)
289 {
290 struct rb_node **p = &root->rb_node;
291 struct rb_node *parent = NULL;
292 struct tree_entry *entry;
293
294 while (*p) {
295 parent = *p;
296 entry = rb_entry(parent, struct tree_entry, rb_node);
297
298 if (bytenr < entry->bytenr)
299 p = &(*p)->rb_left;
300 else if (bytenr > entry->bytenr)
301 p = &(*p)->rb_right;
302 else
303 return parent;
304 }
305
306 rb_link_node(node, parent, p);
307 rb_insert_color(node, root);
308 return NULL;
309 }
310
311 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
312 {
313 struct rb_node *n = root->rb_node;
314 struct tree_entry *entry;
315
316 while (n) {
317 entry = rb_entry(n, struct tree_entry, rb_node);
318
319 if (bytenr < entry->bytenr)
320 n = n->rb_left;
321 else if (bytenr > entry->bytenr)
322 n = n->rb_right;
323 else
324 return n;
325 }
326 return NULL;
327 }
328
329 /*
330 * walk up backref nodes until reach node presents tree root
331 */
332 static struct backref_node *walk_up_backref(struct backref_node *node,
333 struct backref_edge *edges[],
334 int *index)
335 {
336 struct backref_edge *edge;
337 int idx = *index;
338
339 while (!list_empty(&node->upper)) {
340 edge = list_entry(node->upper.next,
341 struct backref_edge, list[LOWER]);
342 edges[idx++] = edge;
343 node = edge->node[UPPER];
344 }
345 BUG_ON(node->detached);
346 *index = idx;
347 return node;
348 }
349
350 /*
351 * walk down backref nodes to find start of next reference path
352 */
353 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
354 int *index)
355 {
356 struct backref_edge *edge;
357 struct backref_node *lower;
358 int idx = *index;
359
360 while (idx > 0) {
361 edge = edges[idx - 1];
362 lower = edge->node[LOWER];
363 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
364 idx--;
365 continue;
366 }
367 edge = list_entry(edge->list[LOWER].next,
368 struct backref_edge, list[LOWER]);
369 edges[idx - 1] = edge;
370 *index = idx;
371 return edge->node[UPPER];
372 }
373 *index = 0;
374 return NULL;
375 }
376
377 static void unlock_node_buffer(struct backref_node *node)
378 {
379 if (node->locked) {
380 btrfs_tree_unlock(node->eb);
381 node->locked = 0;
382 }
383 }
384
385 static void drop_node_buffer(struct backref_node *node)
386 {
387 if (node->eb) {
388 unlock_node_buffer(node);
389 free_extent_buffer(node->eb);
390 node->eb = NULL;
391 }
392 }
393
394 static void drop_backref_node(struct backref_cache *tree,
395 struct backref_node *node)
396 {
397 BUG_ON(!list_empty(&node->upper));
398
399 drop_node_buffer(node);
400 list_del(&node->list);
401 list_del(&node->lower);
402 if (!RB_EMPTY_NODE(&node->rb_node))
403 rb_erase(&node->rb_node, &tree->rb_root);
404 free_backref_node(tree, node);
405 }
406
407 /*
408 * remove a backref node from the backref cache
409 */
410 static void remove_backref_node(struct backref_cache *cache,
411 struct backref_node *node)
412 {
413 struct backref_node *upper;
414 struct backref_edge *edge;
415
416 if (!node)
417 return;
418
419 BUG_ON(!node->lowest && !node->detached);
420 while (!list_empty(&node->upper)) {
421 edge = list_entry(node->upper.next, struct backref_edge,
422 list[LOWER]);
423 upper = edge->node[UPPER];
424 list_del(&edge->list[LOWER]);
425 list_del(&edge->list[UPPER]);
426 free_backref_edge(cache, edge);
427
428 if (RB_EMPTY_NODE(&upper->rb_node)) {
429 BUG_ON(!list_empty(&node->upper));
430 drop_backref_node(cache, node);
431 node = upper;
432 node->lowest = 1;
433 continue;
434 }
435 /*
436 * add the node to leaf node list if no other
437 * child block cached.
438 */
439 if (list_empty(&upper->lower)) {
440 list_add_tail(&upper->lower, &cache->leaves);
441 upper->lowest = 1;
442 }
443 }
444
445 drop_backref_node(cache, node);
446 }
447
448 static void update_backref_node(struct backref_cache *cache,
449 struct backref_node *node, u64 bytenr)
450 {
451 struct rb_node *rb_node;
452 rb_erase(&node->rb_node, &cache->rb_root);
453 node->bytenr = bytenr;
454 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
455 BUG_ON(rb_node);
456 }
457
458 /*
459 * update backref cache after a transaction commit
460 */
461 static int update_backref_cache(struct btrfs_trans_handle *trans,
462 struct backref_cache *cache)
463 {
464 struct backref_node *node;
465 int level = 0;
466
467 if (cache->last_trans == 0) {
468 cache->last_trans = trans->transid;
469 return 0;
470 }
471
472 if (cache->last_trans == trans->transid)
473 return 0;
474
475 /*
476 * detached nodes are used to avoid unnecessary backref
477 * lookup. transaction commit changes the extent tree.
478 * so the detached nodes are no longer useful.
479 */
480 while (!list_empty(&cache->detached)) {
481 node = list_entry(cache->detached.next,
482 struct backref_node, list);
483 remove_backref_node(cache, node);
484 }
485
486 while (!list_empty(&cache->changed)) {
487 node = list_entry(cache->changed.next,
488 struct backref_node, list);
489 list_del_init(&node->list);
490 BUG_ON(node->pending);
491 update_backref_node(cache, node, node->new_bytenr);
492 }
493
494 /*
495 * some nodes can be left in the pending list if there were
496 * errors during processing the pending nodes.
497 */
498 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
499 list_for_each_entry(node, &cache->pending[level], list) {
500 BUG_ON(!node->pending);
501 if (node->bytenr == node->new_bytenr)
502 continue;
503 update_backref_node(cache, node, node->new_bytenr);
504 }
505 }
506
507 cache->last_trans = 0;
508 return 1;
509 }
510
511 static int should_ignore_root(struct btrfs_root *root)
512 {
513 struct btrfs_root *reloc_root;
514
515 if (!root->ref_cows)
516 return 0;
517
518 reloc_root = root->reloc_root;
519 if (!reloc_root)
520 return 0;
521
522 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
523 root->fs_info->running_transaction->transid - 1)
524 return 0;
525 /*
526 * if there is reloc tree and it was created in previous
527 * transaction backref lookup can find the reloc tree,
528 * so backref node for the fs tree root is useless for
529 * relocation.
530 */
531 return 1;
532 }
533
534 /*
535 * find reloc tree by address of tree root
536 */
537 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
538 u64 bytenr)
539 {
540 struct rb_node *rb_node;
541 struct mapping_node *node;
542 struct btrfs_root *root = NULL;
543
544 spin_lock(&rc->reloc_root_tree.lock);
545 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
546 if (rb_node) {
547 node = rb_entry(rb_node, struct mapping_node, rb_node);
548 root = (struct btrfs_root *)node->data;
549 }
550 spin_unlock(&rc->reloc_root_tree.lock);
551 return root;
552 }
553
554 static int is_cowonly_root(u64 root_objectid)
555 {
556 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
557 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
558 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
559 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
560 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
561 root_objectid == BTRFS_CSUM_TREE_OBJECTID)
562 return 1;
563 return 0;
564 }
565
566 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
567 u64 root_objectid)
568 {
569 struct btrfs_key key;
570
571 key.objectid = root_objectid;
572 key.type = BTRFS_ROOT_ITEM_KEY;
573 if (is_cowonly_root(root_objectid))
574 key.offset = 0;
575 else
576 key.offset = (u64)-1;
577
578 return btrfs_read_fs_root_no_name(fs_info, &key);
579 }
580
581 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
582 static noinline_for_stack
583 struct btrfs_root *find_tree_root(struct reloc_control *rc,
584 struct extent_buffer *leaf,
585 struct btrfs_extent_ref_v0 *ref0)
586 {
587 struct btrfs_root *root;
588 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
589 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
590
591 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
592
593 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
594 BUG_ON(IS_ERR(root));
595
596 if (root->ref_cows &&
597 generation != btrfs_root_generation(&root->root_item))
598 return NULL;
599
600 return root;
601 }
602 #endif
603
604 static noinline_for_stack
605 int find_inline_backref(struct extent_buffer *leaf, int slot,
606 unsigned long *ptr, unsigned long *end)
607 {
608 struct btrfs_extent_item *ei;
609 struct btrfs_tree_block_info *bi;
610 u32 item_size;
611
612 item_size = btrfs_item_size_nr(leaf, slot);
613 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
614 if (item_size < sizeof(*ei)) {
615 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
616 return 1;
617 }
618 #endif
619 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
620 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
621 BTRFS_EXTENT_FLAG_TREE_BLOCK));
622
623 if (item_size <= sizeof(*ei) + sizeof(*bi)) {
624 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
625 return 1;
626 }
627
628 bi = (struct btrfs_tree_block_info *)(ei + 1);
629 *ptr = (unsigned long)(bi + 1);
630 *end = (unsigned long)ei + item_size;
631 return 0;
632 }
633
634 /*
635 * build backref tree for a given tree block. root of the backref tree
636 * corresponds the tree block, leaves of the backref tree correspond
637 * roots of b-trees that reference the tree block.
638 *
639 * the basic idea of this function is check backrefs of a given block
640 * to find upper level blocks that refernece the block, and then check
641 * bakcrefs of these upper level blocks recursively. the recursion stop
642 * when tree root is reached or backrefs for the block is cached.
643 *
644 * NOTE: if we find backrefs for a block are cached, we know backrefs
645 * for all upper level blocks that directly/indirectly reference the
646 * block are also cached.
647 */
648 static noinline_for_stack
649 struct backref_node *build_backref_tree(struct reloc_control *rc,
650 struct btrfs_key *node_key,
651 int level, u64 bytenr)
652 {
653 struct backref_cache *cache = &rc->backref_cache;
654 struct btrfs_path *path1;
655 struct btrfs_path *path2;
656 struct extent_buffer *eb;
657 struct btrfs_root *root;
658 struct backref_node *cur;
659 struct backref_node *upper;
660 struct backref_node *lower;
661 struct backref_node *node = NULL;
662 struct backref_node *exist = NULL;
663 struct backref_edge *edge;
664 struct rb_node *rb_node;
665 struct btrfs_key key;
666 unsigned long end;
667 unsigned long ptr;
668 LIST_HEAD(list);
669 LIST_HEAD(useless);
670 int cowonly;
671 int ret;
672 int err = 0;
673
674 path1 = btrfs_alloc_path();
675 path2 = btrfs_alloc_path();
676 if (!path1 || !path2) {
677 err = -ENOMEM;
678 goto out;
679 }
680
681 node = alloc_backref_node(cache);
682 if (!node) {
683 err = -ENOMEM;
684 goto out;
685 }
686
687 node->bytenr = bytenr;
688 node->level = level;
689 node->lowest = 1;
690 cur = node;
691 again:
692 end = 0;
693 ptr = 0;
694 key.objectid = cur->bytenr;
695 key.type = BTRFS_EXTENT_ITEM_KEY;
696 key.offset = (u64)-1;
697
698 path1->search_commit_root = 1;
699 path1->skip_locking = 1;
700 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
701 0, 0);
702 if (ret < 0) {
703 err = ret;
704 goto out;
705 }
706 BUG_ON(!ret || !path1->slots[0]);
707
708 path1->slots[0]--;
709
710 WARN_ON(cur->checked);
711 if (!list_empty(&cur->upper)) {
712 /*
713 * the backref was added previously when processsing
714 * backref of type BTRFS_TREE_BLOCK_REF_KEY
715 */
716 BUG_ON(!list_is_singular(&cur->upper));
717 edge = list_entry(cur->upper.next, struct backref_edge,
718 list[LOWER]);
719 BUG_ON(!list_empty(&edge->list[UPPER]));
720 exist = edge->node[UPPER];
721 /*
722 * add the upper level block to pending list if we need
723 * check its backrefs
724 */
725 if (!exist->checked)
726 list_add_tail(&edge->list[UPPER], &list);
727 } else {
728 exist = NULL;
729 }
730
731 while (1) {
732 cond_resched();
733 eb = path1->nodes[0];
734
735 if (ptr >= end) {
736 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
737 ret = btrfs_next_leaf(rc->extent_root, path1);
738 if (ret < 0) {
739 err = ret;
740 goto out;
741 }
742 if (ret > 0)
743 break;
744 eb = path1->nodes[0];
745 }
746
747 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
748 if (key.objectid != cur->bytenr) {
749 WARN_ON(exist);
750 break;
751 }
752
753 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
754 ret = find_inline_backref(eb, path1->slots[0],
755 &ptr, &end);
756 if (ret)
757 goto next;
758 }
759 }
760
761 if (ptr < end) {
762 /* update key for inline back ref */
763 struct btrfs_extent_inline_ref *iref;
764 iref = (struct btrfs_extent_inline_ref *)ptr;
765 key.type = btrfs_extent_inline_ref_type(eb, iref);
766 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
767 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
768 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
769 }
770
771 if (exist &&
772 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
773 exist->owner == key.offset) ||
774 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
775 exist->bytenr == key.offset))) {
776 exist = NULL;
777 goto next;
778 }
779
780 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
781 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
782 key.type == BTRFS_EXTENT_REF_V0_KEY) {
783 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
784 struct btrfs_extent_ref_v0 *ref0;
785 ref0 = btrfs_item_ptr(eb, path1->slots[0],
786 struct btrfs_extent_ref_v0);
787 if (key.objectid == key.offset) {
788 root = find_tree_root(rc, eb, ref0);
789 if (root && !should_ignore_root(root))
790 cur->root = root;
791 else
792 list_add(&cur->list, &useless);
793 break;
794 }
795 if (is_cowonly_root(btrfs_ref_root_v0(eb,
796 ref0)))
797 cur->cowonly = 1;
798 }
799 #else
800 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
801 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
802 #endif
803 if (key.objectid == key.offset) {
804 /*
805 * only root blocks of reloc trees use
806 * backref of this type.
807 */
808 root = find_reloc_root(rc, cur->bytenr);
809 BUG_ON(!root);
810 cur->root = root;
811 break;
812 }
813
814 edge = alloc_backref_edge(cache);
815 if (!edge) {
816 err = -ENOMEM;
817 goto out;
818 }
819 rb_node = tree_search(&cache->rb_root, key.offset);
820 if (!rb_node) {
821 upper = alloc_backref_node(cache);
822 if (!upper) {
823 free_backref_edge(cache, edge);
824 err = -ENOMEM;
825 goto out;
826 }
827 upper->bytenr = key.offset;
828 upper->level = cur->level + 1;
829 /*
830 * backrefs for the upper level block isn't
831 * cached, add the block to pending list
832 */
833 list_add_tail(&edge->list[UPPER], &list);
834 } else {
835 upper = rb_entry(rb_node, struct backref_node,
836 rb_node);
837 BUG_ON(!upper->checked);
838 INIT_LIST_HEAD(&edge->list[UPPER]);
839 }
840 list_add_tail(&edge->list[LOWER], &cur->upper);
841 edge->node[LOWER] = cur;
842 edge->node[UPPER] = upper;
843
844 goto next;
845 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
846 goto next;
847 }
848
849 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
850 root = read_fs_root(rc->extent_root->fs_info, key.offset);
851 if (IS_ERR(root)) {
852 err = PTR_ERR(root);
853 goto out;
854 }
855
856 if (!root->ref_cows)
857 cur->cowonly = 1;
858
859 if (btrfs_root_level(&root->root_item) == cur->level) {
860 /* tree root */
861 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
862 cur->bytenr);
863 if (should_ignore_root(root))
864 list_add(&cur->list, &useless);
865 else
866 cur->root = root;
867 break;
868 }
869
870 level = cur->level + 1;
871
872 /*
873 * searching the tree to find upper level blocks
874 * reference the block.
875 */
876 path2->search_commit_root = 1;
877 path2->skip_locking = 1;
878 path2->lowest_level = level;
879 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
880 path2->lowest_level = 0;
881 if (ret < 0) {
882 err = ret;
883 goto out;
884 }
885 if (ret > 0 && path2->slots[level] > 0)
886 path2->slots[level]--;
887
888 eb = path2->nodes[level];
889 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
890 cur->bytenr);
891
892 lower = cur;
893 for (; level < BTRFS_MAX_LEVEL; level++) {
894 if (!path2->nodes[level]) {
895 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
896 lower->bytenr);
897 if (should_ignore_root(root))
898 list_add(&lower->list, &useless);
899 else
900 lower->root = root;
901 break;
902 }
903
904 edge = alloc_backref_edge(cache);
905 if (!edge) {
906 err = -ENOMEM;
907 goto out;
908 }
909
910 eb = path2->nodes[level];
911 rb_node = tree_search(&cache->rb_root, eb->start);
912 if (!rb_node) {
913 upper = alloc_backref_node(cache);
914 if (!upper) {
915 free_backref_edge(cache, edge);
916 err = -ENOMEM;
917 goto out;
918 }
919 upper->bytenr = eb->start;
920 upper->owner = btrfs_header_owner(eb);
921 upper->level = lower->level + 1;
922 if (!root->ref_cows)
923 upper->cowonly = 1;
924
925 /*
926 * if we know the block isn't shared
927 * we can void checking its backrefs.
928 */
929 if (btrfs_block_can_be_shared(root, eb))
930 upper->checked = 0;
931 else
932 upper->checked = 1;
933
934 /*
935 * add the block to pending list if we
936 * need check its backrefs. only block
937 * at 'cur->level + 1' is added to the
938 * tail of pending list. this guarantees
939 * we check backrefs from lower level
940 * blocks to upper level blocks.
941 */
942 if (!upper->checked &&
943 level == cur->level + 1) {
944 list_add_tail(&edge->list[UPPER],
945 &list);
946 } else
947 INIT_LIST_HEAD(&edge->list[UPPER]);
948 } else {
949 upper = rb_entry(rb_node, struct backref_node,
950 rb_node);
951 BUG_ON(!upper->checked);
952 INIT_LIST_HEAD(&edge->list[UPPER]);
953 if (!upper->owner)
954 upper->owner = btrfs_header_owner(eb);
955 }
956 list_add_tail(&edge->list[LOWER], &lower->upper);
957 edge->node[LOWER] = lower;
958 edge->node[UPPER] = upper;
959
960 if (rb_node)
961 break;
962 lower = upper;
963 upper = NULL;
964 }
965 btrfs_release_path(root, path2);
966 next:
967 if (ptr < end) {
968 ptr += btrfs_extent_inline_ref_size(key.type);
969 if (ptr >= end) {
970 WARN_ON(ptr > end);
971 ptr = 0;
972 end = 0;
973 }
974 }
975 if (ptr >= end)
976 path1->slots[0]++;
977 }
978 btrfs_release_path(rc->extent_root, path1);
979
980 cur->checked = 1;
981 WARN_ON(exist);
982
983 /* the pending list isn't empty, take the first block to process */
984 if (!list_empty(&list)) {
985 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
986 list_del_init(&edge->list[UPPER]);
987 cur = edge->node[UPPER];
988 goto again;
989 }
990
991 /*
992 * everything goes well, connect backref nodes and insert backref nodes
993 * into the cache.
994 */
995 BUG_ON(!node->checked);
996 cowonly = node->cowonly;
997 if (!cowonly) {
998 rb_node = tree_insert(&cache->rb_root, node->bytenr,
999 &node->rb_node);
1000 BUG_ON(rb_node);
1001 list_add_tail(&node->lower, &cache->leaves);
1002 }
1003
1004 list_for_each_entry(edge, &node->upper, list[LOWER])
1005 list_add_tail(&edge->list[UPPER], &list);
1006
1007 while (!list_empty(&list)) {
1008 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1009 list_del_init(&edge->list[UPPER]);
1010 upper = edge->node[UPPER];
1011 if (upper->detached) {
1012 list_del(&edge->list[LOWER]);
1013 lower = edge->node[LOWER];
1014 free_backref_edge(cache, edge);
1015 if (list_empty(&lower->upper))
1016 list_add(&lower->list, &useless);
1017 continue;
1018 }
1019
1020 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1021 if (upper->lowest) {
1022 list_del_init(&upper->lower);
1023 upper->lowest = 0;
1024 }
1025
1026 list_add_tail(&edge->list[UPPER], &upper->lower);
1027 continue;
1028 }
1029
1030 BUG_ON(!upper->checked);
1031 BUG_ON(cowonly != upper->cowonly);
1032 if (!cowonly) {
1033 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1034 &upper->rb_node);
1035 BUG_ON(rb_node);
1036 }
1037
1038 list_add_tail(&edge->list[UPPER], &upper->lower);
1039
1040 list_for_each_entry(edge, &upper->upper, list[LOWER])
1041 list_add_tail(&edge->list[UPPER], &list);
1042 }
1043 /*
1044 * process useless backref nodes. backref nodes for tree leaves
1045 * are deleted from the cache. backref nodes for upper level
1046 * tree blocks are left in the cache to avoid unnecessary backref
1047 * lookup.
1048 */
1049 while (!list_empty(&useless)) {
1050 upper = list_entry(useless.next, struct backref_node, list);
1051 list_del_init(&upper->list);
1052 BUG_ON(!list_empty(&upper->upper));
1053 if (upper == node)
1054 node = NULL;
1055 if (upper->lowest) {
1056 list_del_init(&upper->lower);
1057 upper->lowest = 0;
1058 }
1059 while (!list_empty(&upper->lower)) {
1060 edge = list_entry(upper->lower.next,
1061 struct backref_edge, list[UPPER]);
1062 list_del(&edge->list[UPPER]);
1063 list_del(&edge->list[LOWER]);
1064 lower = edge->node[LOWER];
1065 free_backref_edge(cache, edge);
1066
1067 if (list_empty(&lower->upper))
1068 list_add(&lower->list, &useless);
1069 }
1070 __mark_block_processed(rc, upper);
1071 if (upper->level > 0) {
1072 list_add(&upper->list, &cache->detached);
1073 upper->detached = 1;
1074 } else {
1075 rb_erase(&upper->rb_node, &cache->rb_root);
1076 free_backref_node(cache, upper);
1077 }
1078 }
1079 out:
1080 btrfs_free_path(path1);
1081 btrfs_free_path(path2);
1082 if (err) {
1083 while (!list_empty(&useless)) {
1084 lower = list_entry(useless.next,
1085 struct backref_node, upper);
1086 list_del_init(&lower->upper);
1087 }
1088 upper = node;
1089 INIT_LIST_HEAD(&list);
1090 while (upper) {
1091 if (RB_EMPTY_NODE(&upper->rb_node)) {
1092 list_splice_tail(&upper->upper, &list);
1093 free_backref_node(cache, upper);
1094 }
1095
1096 if (list_empty(&list))
1097 break;
1098
1099 edge = list_entry(list.next, struct backref_edge,
1100 list[LOWER]);
1101 list_del(&edge->list[LOWER]);
1102 upper = edge->node[UPPER];
1103 free_backref_edge(cache, edge);
1104 }
1105 return ERR_PTR(err);
1106 }
1107 BUG_ON(node && node->detached);
1108 return node;
1109 }
1110
1111 /*
1112 * helper to add backref node for the newly created snapshot.
1113 * the backref node is created by cloning backref node that
1114 * corresponds to root of source tree
1115 */
1116 static int clone_backref_node(struct btrfs_trans_handle *trans,
1117 struct reloc_control *rc,
1118 struct btrfs_root *src,
1119 struct btrfs_root *dest)
1120 {
1121 struct btrfs_root *reloc_root = src->reloc_root;
1122 struct backref_cache *cache = &rc->backref_cache;
1123 struct backref_node *node = NULL;
1124 struct backref_node *new_node;
1125 struct backref_edge *edge;
1126 struct backref_edge *new_edge;
1127 struct rb_node *rb_node;
1128
1129 if (cache->last_trans > 0)
1130 update_backref_cache(trans, cache);
1131
1132 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1133 if (rb_node) {
1134 node = rb_entry(rb_node, struct backref_node, rb_node);
1135 if (node->detached)
1136 node = NULL;
1137 else
1138 BUG_ON(node->new_bytenr != reloc_root->node->start);
1139 }
1140
1141 if (!node) {
1142 rb_node = tree_search(&cache->rb_root,
1143 reloc_root->commit_root->start);
1144 if (rb_node) {
1145 node = rb_entry(rb_node, struct backref_node,
1146 rb_node);
1147 BUG_ON(node->detached);
1148 }
1149 }
1150
1151 if (!node)
1152 return 0;
1153
1154 new_node = alloc_backref_node(cache);
1155 if (!new_node)
1156 return -ENOMEM;
1157
1158 new_node->bytenr = dest->node->start;
1159 new_node->level = node->level;
1160 new_node->lowest = node->lowest;
1161 new_node->checked = 1;
1162 new_node->root = dest;
1163
1164 if (!node->lowest) {
1165 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1166 new_edge = alloc_backref_edge(cache);
1167 if (!new_edge)
1168 goto fail;
1169
1170 new_edge->node[UPPER] = new_node;
1171 new_edge->node[LOWER] = edge->node[LOWER];
1172 list_add_tail(&new_edge->list[UPPER],
1173 &new_node->lower);
1174 }
1175 }
1176
1177 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1178 &new_node->rb_node);
1179 BUG_ON(rb_node);
1180
1181 if (!new_node->lowest) {
1182 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1183 list_add_tail(&new_edge->list[LOWER],
1184 &new_edge->node[LOWER]->upper);
1185 }
1186 }
1187 return 0;
1188 fail:
1189 while (!list_empty(&new_node->lower)) {
1190 new_edge = list_entry(new_node->lower.next,
1191 struct backref_edge, list[UPPER]);
1192 list_del(&new_edge->list[UPPER]);
1193 free_backref_edge(cache, new_edge);
1194 }
1195 free_backref_node(cache, new_node);
1196 return -ENOMEM;
1197 }
1198
1199 /*
1200 * helper to add 'address of tree root -> reloc tree' mapping
1201 */
1202 static int __add_reloc_root(struct btrfs_root *root)
1203 {
1204 struct rb_node *rb_node;
1205 struct mapping_node *node;
1206 struct reloc_control *rc = root->fs_info->reloc_ctl;
1207
1208 node = kmalloc(sizeof(*node), GFP_NOFS);
1209 BUG_ON(!node);
1210
1211 node->bytenr = root->node->start;
1212 node->data = root;
1213
1214 spin_lock(&rc->reloc_root_tree.lock);
1215 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1216 node->bytenr, &node->rb_node);
1217 spin_unlock(&rc->reloc_root_tree.lock);
1218 BUG_ON(rb_node);
1219
1220 list_add_tail(&root->root_list, &rc->reloc_roots);
1221 return 0;
1222 }
1223
1224 /*
1225 * helper to update/delete the 'address of tree root -> reloc tree'
1226 * mapping
1227 */
1228 static int __update_reloc_root(struct btrfs_root *root, int del)
1229 {
1230 struct rb_node *rb_node;
1231 struct mapping_node *node = NULL;
1232 struct reloc_control *rc = root->fs_info->reloc_ctl;
1233
1234 spin_lock(&rc->reloc_root_tree.lock);
1235 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1236 root->commit_root->start);
1237 if (rb_node) {
1238 node = rb_entry(rb_node, struct mapping_node, rb_node);
1239 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1240 }
1241 spin_unlock(&rc->reloc_root_tree.lock);
1242
1243 BUG_ON((struct btrfs_root *)node->data != root);
1244
1245 if (!del) {
1246 spin_lock(&rc->reloc_root_tree.lock);
1247 node->bytenr = root->node->start;
1248 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1249 node->bytenr, &node->rb_node);
1250 spin_unlock(&rc->reloc_root_tree.lock);
1251 BUG_ON(rb_node);
1252 } else {
1253 list_del_init(&root->root_list);
1254 kfree(node);
1255 }
1256 return 0;
1257 }
1258
1259 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1260 struct btrfs_root *root, u64 objectid)
1261 {
1262 struct btrfs_root *reloc_root;
1263 struct extent_buffer *eb;
1264 struct btrfs_root_item *root_item;
1265 struct btrfs_key root_key;
1266 int ret;
1267
1268 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1269 BUG_ON(!root_item);
1270
1271 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1272 root_key.type = BTRFS_ROOT_ITEM_KEY;
1273 root_key.offset = objectid;
1274
1275 if (root->root_key.objectid == objectid) {
1276 /* called by btrfs_init_reloc_root */
1277 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1278 BTRFS_TREE_RELOC_OBJECTID);
1279 BUG_ON(ret);
1280
1281 btrfs_set_root_last_snapshot(&root->root_item,
1282 trans->transid - 1);
1283 } else {
1284 /*
1285 * called by btrfs_reloc_post_snapshot_hook.
1286 * the source tree is a reloc tree, all tree blocks
1287 * modified after it was created have RELOC flag
1288 * set in their headers. so it's OK to not update
1289 * the 'last_snapshot'.
1290 */
1291 ret = btrfs_copy_root(trans, root, root->node, &eb,
1292 BTRFS_TREE_RELOC_OBJECTID);
1293 BUG_ON(ret);
1294 }
1295
1296 memcpy(root_item, &root->root_item, sizeof(*root_item));
1297 btrfs_set_root_bytenr(root_item, eb->start);
1298 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1299 btrfs_set_root_generation(root_item, trans->transid);
1300
1301 if (root->root_key.objectid == objectid) {
1302 btrfs_set_root_refs(root_item, 0);
1303 memset(&root_item->drop_progress, 0,
1304 sizeof(struct btrfs_disk_key));
1305 root_item->drop_level = 0;
1306 }
1307
1308 btrfs_tree_unlock(eb);
1309 free_extent_buffer(eb);
1310
1311 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1312 &root_key, root_item);
1313 BUG_ON(ret);
1314 kfree(root_item);
1315
1316 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
1317 &root_key);
1318 BUG_ON(IS_ERR(reloc_root));
1319 reloc_root->last_trans = trans->transid;
1320 return reloc_root;
1321 }
1322
1323 /*
1324 * create reloc tree for a given fs tree. reloc tree is just a
1325 * snapshot of the fs tree with special root objectid.
1326 */
1327 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1328 struct btrfs_root *root)
1329 {
1330 struct btrfs_root *reloc_root;
1331 struct reloc_control *rc = root->fs_info->reloc_ctl;
1332 int clear_rsv = 0;
1333
1334 if (root->reloc_root) {
1335 reloc_root = root->reloc_root;
1336 reloc_root->last_trans = trans->transid;
1337 return 0;
1338 }
1339
1340 if (!rc || !rc->create_reloc_tree ||
1341 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1342 return 0;
1343
1344 if (!trans->block_rsv) {
1345 trans->block_rsv = rc->block_rsv;
1346 clear_rsv = 1;
1347 }
1348 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1349 if (clear_rsv)
1350 trans->block_rsv = NULL;
1351
1352 __add_reloc_root(reloc_root);
1353 root->reloc_root = reloc_root;
1354 return 0;
1355 }
1356
1357 /*
1358 * update root item of reloc tree
1359 */
1360 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1361 struct btrfs_root *root)
1362 {
1363 struct btrfs_root *reloc_root;
1364 struct btrfs_root_item *root_item;
1365 int del = 0;
1366 int ret;
1367
1368 if (!root->reloc_root)
1369 return 0;
1370
1371 reloc_root = root->reloc_root;
1372 root_item = &reloc_root->root_item;
1373
1374 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1375 btrfs_root_refs(root_item) == 0) {
1376 root->reloc_root = NULL;
1377 del = 1;
1378 }
1379
1380 __update_reloc_root(reloc_root, del);
1381
1382 if (reloc_root->commit_root != reloc_root->node) {
1383 btrfs_set_root_node(root_item, reloc_root->node);
1384 free_extent_buffer(reloc_root->commit_root);
1385 reloc_root->commit_root = btrfs_root_node(reloc_root);
1386 }
1387
1388 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1389 &reloc_root->root_key, root_item);
1390 BUG_ON(ret);
1391 return 0;
1392 }
1393
1394 /*
1395 * helper to find first cached inode with inode number >= objectid
1396 * in a subvolume
1397 */
1398 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1399 {
1400 struct rb_node *node;
1401 struct rb_node *prev;
1402 struct btrfs_inode *entry;
1403 struct inode *inode;
1404
1405 spin_lock(&root->inode_lock);
1406 again:
1407 node = root->inode_tree.rb_node;
1408 prev = NULL;
1409 while (node) {
1410 prev = node;
1411 entry = rb_entry(node, struct btrfs_inode, rb_node);
1412
1413 if (objectid < entry->vfs_inode.i_ino)
1414 node = node->rb_left;
1415 else if (objectid > entry->vfs_inode.i_ino)
1416 node = node->rb_right;
1417 else
1418 break;
1419 }
1420 if (!node) {
1421 while (prev) {
1422 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1423 if (objectid <= entry->vfs_inode.i_ino) {
1424 node = prev;
1425 break;
1426 }
1427 prev = rb_next(prev);
1428 }
1429 }
1430 while (node) {
1431 entry = rb_entry(node, struct btrfs_inode, rb_node);
1432 inode = igrab(&entry->vfs_inode);
1433 if (inode) {
1434 spin_unlock(&root->inode_lock);
1435 return inode;
1436 }
1437
1438 objectid = entry->vfs_inode.i_ino + 1;
1439 if (cond_resched_lock(&root->inode_lock))
1440 goto again;
1441
1442 node = rb_next(node);
1443 }
1444 spin_unlock(&root->inode_lock);
1445 return NULL;
1446 }
1447
1448 static int in_block_group(u64 bytenr,
1449 struct btrfs_block_group_cache *block_group)
1450 {
1451 if (bytenr >= block_group->key.objectid &&
1452 bytenr < block_group->key.objectid + block_group->key.offset)
1453 return 1;
1454 return 0;
1455 }
1456
1457 /*
1458 * get new location of data
1459 */
1460 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1461 u64 bytenr, u64 num_bytes)
1462 {
1463 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1464 struct btrfs_path *path;
1465 struct btrfs_file_extent_item *fi;
1466 struct extent_buffer *leaf;
1467 int ret;
1468
1469 path = btrfs_alloc_path();
1470 if (!path)
1471 return -ENOMEM;
1472
1473 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1474 ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
1475 bytenr, 0);
1476 if (ret < 0)
1477 goto out;
1478 if (ret > 0) {
1479 ret = -ENOENT;
1480 goto out;
1481 }
1482
1483 leaf = path->nodes[0];
1484 fi = btrfs_item_ptr(leaf, path->slots[0],
1485 struct btrfs_file_extent_item);
1486
1487 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1488 btrfs_file_extent_compression(leaf, fi) ||
1489 btrfs_file_extent_encryption(leaf, fi) ||
1490 btrfs_file_extent_other_encoding(leaf, fi));
1491
1492 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1493 ret = 1;
1494 goto out;
1495 }
1496
1497 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1498 ret = 0;
1499 out:
1500 btrfs_free_path(path);
1501 return ret;
1502 }
1503
1504 /*
1505 * update file extent items in the tree leaf to point to
1506 * the new locations.
1507 */
1508 static noinline_for_stack
1509 int replace_file_extents(struct btrfs_trans_handle *trans,
1510 struct reloc_control *rc,
1511 struct btrfs_root *root,
1512 struct extent_buffer *leaf)
1513 {
1514 struct btrfs_key key;
1515 struct btrfs_file_extent_item *fi;
1516 struct inode *inode = NULL;
1517 u64 parent;
1518 u64 bytenr;
1519 u64 new_bytenr = 0;
1520 u64 num_bytes;
1521 u64 end;
1522 u32 nritems;
1523 u32 i;
1524 int ret;
1525 int first = 1;
1526 int dirty = 0;
1527
1528 if (rc->stage != UPDATE_DATA_PTRS)
1529 return 0;
1530
1531 /* reloc trees always use full backref */
1532 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1533 parent = leaf->start;
1534 else
1535 parent = 0;
1536
1537 nritems = btrfs_header_nritems(leaf);
1538 for (i = 0; i < nritems; i++) {
1539 cond_resched();
1540 btrfs_item_key_to_cpu(leaf, &key, i);
1541 if (key.type != BTRFS_EXTENT_DATA_KEY)
1542 continue;
1543 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1544 if (btrfs_file_extent_type(leaf, fi) ==
1545 BTRFS_FILE_EXTENT_INLINE)
1546 continue;
1547 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1548 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1549 if (bytenr == 0)
1550 continue;
1551 if (!in_block_group(bytenr, rc->block_group))
1552 continue;
1553
1554 /*
1555 * if we are modifying block in fs tree, wait for readpage
1556 * to complete and drop the extent cache
1557 */
1558 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1559 if (first) {
1560 inode = find_next_inode(root, key.objectid);
1561 first = 0;
1562 } else if (inode && inode->i_ino < key.objectid) {
1563 btrfs_add_delayed_iput(inode);
1564 inode = find_next_inode(root, key.objectid);
1565 }
1566 if (inode && inode->i_ino == key.objectid) {
1567 end = key.offset +
1568 btrfs_file_extent_num_bytes(leaf, fi);
1569 WARN_ON(!IS_ALIGNED(key.offset,
1570 root->sectorsize));
1571 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1572 end--;
1573 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1574 key.offset, end,
1575 GFP_NOFS);
1576 if (!ret)
1577 continue;
1578
1579 btrfs_drop_extent_cache(inode, key.offset, end,
1580 1);
1581 unlock_extent(&BTRFS_I(inode)->io_tree,
1582 key.offset, end, GFP_NOFS);
1583 }
1584 }
1585
1586 ret = get_new_location(rc->data_inode, &new_bytenr,
1587 bytenr, num_bytes);
1588 if (ret > 0) {
1589 WARN_ON(1);
1590 continue;
1591 }
1592 BUG_ON(ret < 0);
1593
1594 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1595 dirty = 1;
1596
1597 key.offset -= btrfs_file_extent_offset(leaf, fi);
1598 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1599 num_bytes, parent,
1600 btrfs_header_owner(leaf),
1601 key.objectid, key.offset);
1602 BUG_ON(ret);
1603
1604 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1605 parent, btrfs_header_owner(leaf),
1606 key.objectid, key.offset);
1607 BUG_ON(ret);
1608 }
1609 if (dirty)
1610 btrfs_mark_buffer_dirty(leaf);
1611 if (inode)
1612 btrfs_add_delayed_iput(inode);
1613 return 0;
1614 }
1615
1616 static noinline_for_stack
1617 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1618 struct btrfs_path *path, int level)
1619 {
1620 struct btrfs_disk_key key1;
1621 struct btrfs_disk_key key2;
1622 btrfs_node_key(eb, &key1, slot);
1623 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1624 return memcmp(&key1, &key2, sizeof(key1));
1625 }
1626
1627 /*
1628 * try to replace tree blocks in fs tree with the new blocks
1629 * in reloc tree. tree blocks haven't been modified since the
1630 * reloc tree was create can be replaced.
1631 *
1632 * if a block was replaced, level of the block + 1 is returned.
1633 * if no block got replaced, 0 is returned. if there are other
1634 * errors, a negative error number is returned.
1635 */
1636 static noinline_for_stack
1637 int replace_path(struct btrfs_trans_handle *trans,
1638 struct btrfs_root *dest, struct btrfs_root *src,
1639 struct btrfs_path *path, struct btrfs_key *next_key,
1640 int lowest_level, int max_level)
1641 {
1642 struct extent_buffer *eb;
1643 struct extent_buffer *parent;
1644 struct btrfs_key key;
1645 u64 old_bytenr;
1646 u64 new_bytenr;
1647 u64 old_ptr_gen;
1648 u64 new_ptr_gen;
1649 u64 last_snapshot;
1650 u32 blocksize;
1651 int cow = 0;
1652 int level;
1653 int ret;
1654 int slot;
1655
1656 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1657 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1658
1659 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1660 again:
1661 slot = path->slots[lowest_level];
1662 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1663
1664 eb = btrfs_lock_root_node(dest);
1665 btrfs_set_lock_blocking(eb);
1666 level = btrfs_header_level(eb);
1667
1668 if (level < lowest_level) {
1669 btrfs_tree_unlock(eb);
1670 free_extent_buffer(eb);
1671 return 0;
1672 }
1673
1674 if (cow) {
1675 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1676 BUG_ON(ret);
1677 }
1678 btrfs_set_lock_blocking(eb);
1679
1680 if (next_key) {
1681 next_key->objectid = (u64)-1;
1682 next_key->type = (u8)-1;
1683 next_key->offset = (u64)-1;
1684 }
1685
1686 parent = eb;
1687 while (1) {
1688 level = btrfs_header_level(parent);
1689 BUG_ON(level < lowest_level);
1690
1691 ret = btrfs_bin_search(parent, &key, level, &slot);
1692 if (ret && slot > 0)
1693 slot--;
1694
1695 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1696 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1697
1698 old_bytenr = btrfs_node_blockptr(parent, slot);
1699 blocksize = btrfs_level_size(dest, level - 1);
1700 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1701
1702 if (level <= max_level) {
1703 eb = path->nodes[level];
1704 new_bytenr = btrfs_node_blockptr(eb,
1705 path->slots[level]);
1706 new_ptr_gen = btrfs_node_ptr_generation(eb,
1707 path->slots[level]);
1708 } else {
1709 new_bytenr = 0;
1710 new_ptr_gen = 0;
1711 }
1712
1713 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1714 WARN_ON(1);
1715 ret = level;
1716 break;
1717 }
1718
1719 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1720 memcmp_node_keys(parent, slot, path, level)) {
1721 if (level <= lowest_level) {
1722 ret = 0;
1723 break;
1724 }
1725
1726 eb = read_tree_block(dest, old_bytenr, blocksize,
1727 old_ptr_gen);
1728 BUG_ON(!eb);
1729 btrfs_tree_lock(eb);
1730 if (cow) {
1731 ret = btrfs_cow_block(trans, dest, eb, parent,
1732 slot, &eb);
1733 BUG_ON(ret);
1734 }
1735 btrfs_set_lock_blocking(eb);
1736
1737 btrfs_tree_unlock(parent);
1738 free_extent_buffer(parent);
1739
1740 parent = eb;
1741 continue;
1742 }
1743
1744 if (!cow) {
1745 btrfs_tree_unlock(parent);
1746 free_extent_buffer(parent);
1747 cow = 1;
1748 goto again;
1749 }
1750
1751 btrfs_node_key_to_cpu(path->nodes[level], &key,
1752 path->slots[level]);
1753 btrfs_release_path(src, path);
1754
1755 path->lowest_level = level;
1756 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1757 path->lowest_level = 0;
1758 BUG_ON(ret);
1759
1760 /*
1761 * swap blocks in fs tree and reloc tree.
1762 */
1763 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1764 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1765 btrfs_mark_buffer_dirty(parent);
1766
1767 btrfs_set_node_blockptr(path->nodes[level],
1768 path->slots[level], old_bytenr);
1769 btrfs_set_node_ptr_generation(path->nodes[level],
1770 path->slots[level], old_ptr_gen);
1771 btrfs_mark_buffer_dirty(path->nodes[level]);
1772
1773 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1774 path->nodes[level]->start,
1775 src->root_key.objectid, level - 1, 0);
1776 BUG_ON(ret);
1777 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1778 0, dest->root_key.objectid, level - 1,
1779 0);
1780 BUG_ON(ret);
1781
1782 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1783 path->nodes[level]->start,
1784 src->root_key.objectid, level - 1, 0);
1785 BUG_ON(ret);
1786
1787 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1788 0, dest->root_key.objectid, level - 1,
1789 0);
1790 BUG_ON(ret);
1791
1792 btrfs_unlock_up_safe(path, 0);
1793
1794 ret = level;
1795 break;
1796 }
1797 btrfs_tree_unlock(parent);
1798 free_extent_buffer(parent);
1799 return ret;
1800 }
1801
1802 /*
1803 * helper to find next relocated block in reloc tree
1804 */
1805 static noinline_for_stack
1806 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1807 int *level)
1808 {
1809 struct extent_buffer *eb;
1810 int i;
1811 u64 last_snapshot;
1812 u32 nritems;
1813
1814 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1815
1816 for (i = 0; i < *level; i++) {
1817 free_extent_buffer(path->nodes[i]);
1818 path->nodes[i] = NULL;
1819 }
1820
1821 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1822 eb = path->nodes[i];
1823 nritems = btrfs_header_nritems(eb);
1824 while (path->slots[i] + 1 < nritems) {
1825 path->slots[i]++;
1826 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1827 last_snapshot)
1828 continue;
1829
1830 *level = i;
1831 return 0;
1832 }
1833 free_extent_buffer(path->nodes[i]);
1834 path->nodes[i] = NULL;
1835 }
1836 return 1;
1837 }
1838
1839 /*
1840 * walk down reloc tree to find relocated block of lowest level
1841 */
1842 static noinline_for_stack
1843 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1844 int *level)
1845 {
1846 struct extent_buffer *eb = NULL;
1847 int i;
1848 u64 bytenr;
1849 u64 ptr_gen = 0;
1850 u64 last_snapshot;
1851 u32 blocksize;
1852 u32 nritems;
1853
1854 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1855
1856 for (i = *level; i > 0; i--) {
1857 eb = path->nodes[i];
1858 nritems = btrfs_header_nritems(eb);
1859 while (path->slots[i] < nritems) {
1860 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1861 if (ptr_gen > last_snapshot)
1862 break;
1863 path->slots[i]++;
1864 }
1865 if (path->slots[i] >= nritems) {
1866 if (i == *level)
1867 break;
1868 *level = i + 1;
1869 return 0;
1870 }
1871 if (i == 1) {
1872 *level = i;
1873 return 0;
1874 }
1875
1876 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1877 blocksize = btrfs_level_size(root, i - 1);
1878 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1879 BUG_ON(btrfs_header_level(eb) != i - 1);
1880 path->nodes[i - 1] = eb;
1881 path->slots[i - 1] = 0;
1882 }
1883 return 1;
1884 }
1885
1886 /*
1887 * invalidate extent cache for file extents whose key in range of
1888 * [min_key, max_key)
1889 */
1890 static int invalidate_extent_cache(struct btrfs_root *root,
1891 struct btrfs_key *min_key,
1892 struct btrfs_key *max_key)
1893 {
1894 struct inode *inode = NULL;
1895 u64 objectid;
1896 u64 start, end;
1897
1898 objectid = min_key->objectid;
1899 while (1) {
1900 cond_resched();
1901 iput(inode);
1902
1903 if (objectid > max_key->objectid)
1904 break;
1905
1906 inode = find_next_inode(root, objectid);
1907 if (!inode)
1908 break;
1909
1910 if (inode->i_ino > max_key->objectid) {
1911 iput(inode);
1912 break;
1913 }
1914
1915 objectid = inode->i_ino + 1;
1916 if (!S_ISREG(inode->i_mode))
1917 continue;
1918
1919 if (unlikely(min_key->objectid == inode->i_ino)) {
1920 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1921 continue;
1922 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1923 start = 0;
1924 else {
1925 start = min_key->offset;
1926 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1927 }
1928 } else {
1929 start = 0;
1930 }
1931
1932 if (unlikely(max_key->objectid == inode->i_ino)) {
1933 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1934 continue;
1935 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1936 end = (u64)-1;
1937 } else {
1938 if (max_key->offset == 0)
1939 continue;
1940 end = max_key->offset;
1941 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1942 end--;
1943 }
1944 } else {
1945 end = (u64)-1;
1946 }
1947
1948 /* the lock_extent waits for readpage to complete */
1949 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1950 btrfs_drop_extent_cache(inode, start, end, 1);
1951 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1952 }
1953 return 0;
1954 }
1955
1956 static int find_next_key(struct btrfs_path *path, int level,
1957 struct btrfs_key *key)
1958
1959 {
1960 while (level < BTRFS_MAX_LEVEL) {
1961 if (!path->nodes[level])
1962 break;
1963 if (path->slots[level] + 1 <
1964 btrfs_header_nritems(path->nodes[level])) {
1965 btrfs_node_key_to_cpu(path->nodes[level], key,
1966 path->slots[level] + 1);
1967 return 0;
1968 }
1969 level++;
1970 }
1971 return 1;
1972 }
1973
1974 /*
1975 * merge the relocated tree blocks in reloc tree with corresponding
1976 * fs tree.
1977 */
1978 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1979 struct btrfs_root *root)
1980 {
1981 LIST_HEAD(inode_list);
1982 struct btrfs_key key;
1983 struct btrfs_key next_key;
1984 struct btrfs_trans_handle *trans;
1985 struct btrfs_root *reloc_root;
1986 struct btrfs_root_item *root_item;
1987 struct btrfs_path *path;
1988 struct extent_buffer *leaf;
1989 unsigned long nr;
1990 int level;
1991 int max_level;
1992 int replaced = 0;
1993 int ret;
1994 int err = 0;
1995 u32 min_reserved;
1996
1997 path = btrfs_alloc_path();
1998 if (!path)
1999 return -ENOMEM;
2000
2001 reloc_root = root->reloc_root;
2002 root_item = &reloc_root->root_item;
2003
2004 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2005 level = btrfs_root_level(root_item);
2006 extent_buffer_get(reloc_root->node);
2007 path->nodes[level] = reloc_root->node;
2008 path->slots[level] = 0;
2009 } else {
2010 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2011
2012 level = root_item->drop_level;
2013 BUG_ON(level == 0);
2014 path->lowest_level = level;
2015 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2016 path->lowest_level = 0;
2017 if (ret < 0) {
2018 btrfs_free_path(path);
2019 return ret;
2020 }
2021
2022 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2023 path->slots[level]);
2024 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2025
2026 btrfs_unlock_up_safe(path, 0);
2027 }
2028
2029 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2030 memset(&next_key, 0, sizeof(next_key));
2031
2032 while (1) {
2033 trans = btrfs_start_transaction(root, 0);
2034 BUG_ON(IS_ERR(trans));
2035 trans->block_rsv = rc->block_rsv;
2036
2037 ret = btrfs_block_rsv_check(trans, root, rc->block_rsv,
2038 min_reserved, 0);
2039 if (ret) {
2040 BUG_ON(ret != -EAGAIN);
2041 ret = btrfs_commit_transaction(trans, root);
2042 BUG_ON(ret);
2043 continue;
2044 }
2045
2046 replaced = 0;
2047 max_level = level;
2048
2049 ret = walk_down_reloc_tree(reloc_root, path, &level);
2050 if (ret < 0) {
2051 err = ret;
2052 goto out;
2053 }
2054 if (ret > 0)
2055 break;
2056
2057 if (!find_next_key(path, level, &key) &&
2058 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2059 ret = 0;
2060 } else {
2061 ret = replace_path(trans, root, reloc_root, path,
2062 &next_key, level, max_level);
2063 }
2064 if (ret < 0) {
2065 err = ret;
2066 goto out;
2067 }
2068
2069 if (ret > 0) {
2070 level = ret;
2071 btrfs_node_key_to_cpu(path->nodes[level], &key,
2072 path->slots[level]);
2073 replaced = 1;
2074 }
2075
2076 ret = walk_up_reloc_tree(reloc_root, path, &level);
2077 if (ret > 0)
2078 break;
2079
2080 BUG_ON(level == 0);
2081 /*
2082 * save the merging progress in the drop_progress.
2083 * this is OK since root refs == 1 in this case.
2084 */
2085 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2086 path->slots[level]);
2087 root_item->drop_level = level;
2088
2089 nr = trans->blocks_used;
2090 btrfs_end_transaction_throttle(trans, root);
2091
2092 btrfs_btree_balance_dirty(root, nr);
2093
2094 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2095 invalidate_extent_cache(root, &key, &next_key);
2096 }
2097
2098 /*
2099 * handle the case only one block in the fs tree need to be
2100 * relocated and the block is tree root.
2101 */
2102 leaf = btrfs_lock_root_node(root);
2103 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2104 btrfs_tree_unlock(leaf);
2105 free_extent_buffer(leaf);
2106 if (ret < 0)
2107 err = ret;
2108 out:
2109 btrfs_free_path(path);
2110
2111 if (err == 0) {
2112 memset(&root_item->drop_progress, 0,
2113 sizeof(root_item->drop_progress));
2114 root_item->drop_level = 0;
2115 btrfs_set_root_refs(root_item, 0);
2116 btrfs_update_reloc_root(trans, root);
2117 }
2118
2119 nr = trans->blocks_used;
2120 btrfs_end_transaction_throttle(trans, root);
2121
2122 btrfs_btree_balance_dirty(root, nr);
2123
2124 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2125 invalidate_extent_cache(root, &key, &next_key);
2126
2127 return err;
2128 }
2129
2130 static noinline_for_stack
2131 int prepare_to_merge(struct reloc_control *rc, int err)
2132 {
2133 struct btrfs_root *root = rc->extent_root;
2134 struct btrfs_root *reloc_root;
2135 struct btrfs_trans_handle *trans;
2136 LIST_HEAD(reloc_roots);
2137 u64 num_bytes = 0;
2138 int ret;
2139
2140 mutex_lock(&root->fs_info->trans_mutex);
2141 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2142 rc->merging_rsv_size += rc->nodes_relocated * 2;
2143 mutex_unlock(&root->fs_info->trans_mutex);
2144 again:
2145 if (!err) {
2146 num_bytes = rc->merging_rsv_size;
2147 ret = btrfs_block_rsv_add(NULL, root, rc->block_rsv,
2148 num_bytes);
2149 if (ret)
2150 err = ret;
2151 }
2152
2153 trans = btrfs_join_transaction(rc->extent_root, 1);
2154 if (IS_ERR(trans)) {
2155 if (!err)
2156 btrfs_block_rsv_release(rc->extent_root,
2157 rc->block_rsv, num_bytes);
2158 return PTR_ERR(trans);
2159 }
2160
2161 if (!err) {
2162 if (num_bytes != rc->merging_rsv_size) {
2163 btrfs_end_transaction(trans, rc->extent_root);
2164 btrfs_block_rsv_release(rc->extent_root,
2165 rc->block_rsv, num_bytes);
2166 goto again;
2167 }
2168 }
2169
2170 rc->merge_reloc_tree = 1;
2171
2172 while (!list_empty(&rc->reloc_roots)) {
2173 reloc_root = list_entry(rc->reloc_roots.next,
2174 struct btrfs_root, root_list);
2175 list_del_init(&reloc_root->root_list);
2176
2177 root = read_fs_root(reloc_root->fs_info,
2178 reloc_root->root_key.offset);
2179 BUG_ON(IS_ERR(root));
2180 BUG_ON(root->reloc_root != reloc_root);
2181
2182 /*
2183 * set reference count to 1, so btrfs_recover_relocation
2184 * knows it should resumes merging
2185 */
2186 if (!err)
2187 btrfs_set_root_refs(&reloc_root->root_item, 1);
2188 btrfs_update_reloc_root(trans, root);
2189
2190 list_add(&reloc_root->root_list, &reloc_roots);
2191 }
2192
2193 list_splice(&reloc_roots, &rc->reloc_roots);
2194
2195 if (!err)
2196 btrfs_commit_transaction(trans, rc->extent_root);
2197 else
2198 btrfs_end_transaction(trans, rc->extent_root);
2199 return err;
2200 }
2201
2202 static noinline_for_stack
2203 int merge_reloc_roots(struct reloc_control *rc)
2204 {
2205 struct btrfs_root *root;
2206 struct btrfs_root *reloc_root;
2207 LIST_HEAD(reloc_roots);
2208 int found = 0;
2209 int ret;
2210 again:
2211 root = rc->extent_root;
2212 mutex_lock(&root->fs_info->trans_mutex);
2213 list_splice_init(&rc->reloc_roots, &reloc_roots);
2214 mutex_unlock(&root->fs_info->trans_mutex);
2215
2216 while (!list_empty(&reloc_roots)) {
2217 found = 1;
2218 reloc_root = list_entry(reloc_roots.next,
2219 struct btrfs_root, root_list);
2220
2221 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2222 root = read_fs_root(reloc_root->fs_info,
2223 reloc_root->root_key.offset);
2224 BUG_ON(IS_ERR(root));
2225 BUG_ON(root->reloc_root != reloc_root);
2226
2227 ret = merge_reloc_root(rc, root);
2228 BUG_ON(ret);
2229 } else {
2230 list_del_init(&reloc_root->root_list);
2231 }
2232 btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0);
2233 }
2234
2235 if (found) {
2236 found = 0;
2237 goto again;
2238 }
2239 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2240 return 0;
2241 }
2242
2243 static void free_block_list(struct rb_root *blocks)
2244 {
2245 struct tree_block *block;
2246 struct rb_node *rb_node;
2247 while ((rb_node = rb_first(blocks))) {
2248 block = rb_entry(rb_node, struct tree_block, rb_node);
2249 rb_erase(rb_node, blocks);
2250 kfree(block);
2251 }
2252 }
2253
2254 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2255 struct btrfs_root *reloc_root)
2256 {
2257 struct btrfs_root *root;
2258
2259 if (reloc_root->last_trans == trans->transid)
2260 return 0;
2261
2262 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2263 BUG_ON(IS_ERR(root));
2264 BUG_ON(root->reloc_root != reloc_root);
2265
2266 return btrfs_record_root_in_trans(trans, root);
2267 }
2268
2269 static noinline_for_stack
2270 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2271 struct reloc_control *rc,
2272 struct backref_node *node,
2273 struct backref_edge *edges[], int *nr)
2274 {
2275 struct backref_node *next;
2276 struct btrfs_root *root;
2277 int index = 0;
2278
2279 next = node;
2280 while (1) {
2281 cond_resched();
2282 next = walk_up_backref(next, edges, &index);
2283 root = next->root;
2284 BUG_ON(!root);
2285 BUG_ON(!root->ref_cows);
2286
2287 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2288 record_reloc_root_in_trans(trans, root);
2289 break;
2290 }
2291
2292 btrfs_record_root_in_trans(trans, root);
2293 root = root->reloc_root;
2294
2295 if (next->new_bytenr != root->node->start) {
2296 BUG_ON(next->new_bytenr);
2297 BUG_ON(!list_empty(&next->list));
2298 next->new_bytenr = root->node->start;
2299 next->root = root;
2300 list_add_tail(&next->list,
2301 &rc->backref_cache.changed);
2302 __mark_block_processed(rc, next);
2303 break;
2304 }
2305
2306 WARN_ON(1);
2307 root = NULL;
2308 next = walk_down_backref(edges, &index);
2309 if (!next || next->level <= node->level)
2310 break;
2311 }
2312 if (!root)
2313 return NULL;
2314
2315 *nr = index;
2316 next = node;
2317 /* setup backref node path for btrfs_reloc_cow_block */
2318 while (1) {
2319 rc->backref_cache.path[next->level] = next;
2320 if (--index < 0)
2321 break;
2322 next = edges[index]->node[UPPER];
2323 }
2324 return root;
2325 }
2326
2327 /*
2328 * select a tree root for relocation. return NULL if the block
2329 * is reference counted. we should use do_relocation() in this
2330 * case. return a tree root pointer if the block isn't reference
2331 * counted. return -ENOENT if the block is root of reloc tree.
2332 */
2333 static noinline_for_stack
2334 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2335 struct backref_node *node)
2336 {
2337 struct backref_node *next;
2338 struct btrfs_root *root;
2339 struct btrfs_root *fs_root = NULL;
2340 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2341 int index = 0;
2342
2343 next = node;
2344 while (1) {
2345 cond_resched();
2346 next = walk_up_backref(next, edges, &index);
2347 root = next->root;
2348 BUG_ON(!root);
2349
2350 /* no other choice for non-refernce counted tree */
2351 if (!root->ref_cows)
2352 return root;
2353
2354 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2355 fs_root = root;
2356
2357 if (next != node)
2358 return NULL;
2359
2360 next = walk_down_backref(edges, &index);
2361 if (!next || next->level <= node->level)
2362 break;
2363 }
2364
2365 if (!fs_root)
2366 return ERR_PTR(-ENOENT);
2367 return fs_root;
2368 }
2369
2370 static noinline_for_stack
2371 u64 calcu_metadata_size(struct reloc_control *rc,
2372 struct backref_node *node, int reserve)
2373 {
2374 struct backref_node *next = node;
2375 struct backref_edge *edge;
2376 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2377 u64 num_bytes = 0;
2378 int index = 0;
2379
2380 BUG_ON(reserve && node->processed);
2381
2382 while (next) {
2383 cond_resched();
2384 while (1) {
2385 if (next->processed && (reserve || next != node))
2386 break;
2387
2388 num_bytes += btrfs_level_size(rc->extent_root,
2389 next->level);
2390
2391 if (list_empty(&next->upper))
2392 break;
2393
2394 edge = list_entry(next->upper.next,
2395 struct backref_edge, list[LOWER]);
2396 edges[index++] = edge;
2397 next = edge->node[UPPER];
2398 }
2399 next = walk_down_backref(edges, &index);
2400 }
2401 return num_bytes;
2402 }
2403
2404 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2405 struct reloc_control *rc,
2406 struct backref_node *node)
2407 {
2408 struct btrfs_root *root = rc->extent_root;
2409 u64 num_bytes;
2410 int ret;
2411
2412 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2413
2414 trans->block_rsv = rc->block_rsv;
2415 ret = btrfs_block_rsv_add(trans, root, rc->block_rsv, num_bytes);
2416 if (ret) {
2417 if (ret == -EAGAIN)
2418 rc->commit_transaction = 1;
2419 return ret;
2420 }
2421
2422 return 0;
2423 }
2424
2425 static void release_metadata_space(struct reloc_control *rc,
2426 struct backref_node *node)
2427 {
2428 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2429 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2430 }
2431
2432 /*
2433 * relocate a block tree, and then update pointers in upper level
2434 * blocks that reference the block to point to the new location.
2435 *
2436 * if called by link_to_upper, the block has already been relocated.
2437 * in that case this function just updates pointers.
2438 */
2439 static int do_relocation(struct btrfs_trans_handle *trans,
2440 struct reloc_control *rc,
2441 struct backref_node *node,
2442 struct btrfs_key *key,
2443 struct btrfs_path *path, int lowest)
2444 {
2445 struct backref_node *upper;
2446 struct backref_edge *edge;
2447 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2448 struct btrfs_root *root;
2449 struct extent_buffer *eb;
2450 u32 blocksize;
2451 u64 bytenr;
2452 u64 generation;
2453 int nr;
2454 int slot;
2455 int ret;
2456 int err = 0;
2457
2458 BUG_ON(lowest && node->eb);
2459
2460 path->lowest_level = node->level + 1;
2461 rc->backref_cache.path[node->level] = node;
2462 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2463 cond_resched();
2464
2465 upper = edge->node[UPPER];
2466 root = select_reloc_root(trans, rc, upper, edges, &nr);
2467 BUG_ON(!root);
2468
2469 if (upper->eb && !upper->locked) {
2470 if (!lowest) {
2471 ret = btrfs_bin_search(upper->eb, key,
2472 upper->level, &slot);
2473 BUG_ON(ret);
2474 bytenr = btrfs_node_blockptr(upper->eb, slot);
2475 if (node->eb->start == bytenr)
2476 goto next;
2477 }
2478 drop_node_buffer(upper);
2479 }
2480
2481 if (!upper->eb) {
2482 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2483 if (ret < 0) {
2484 err = ret;
2485 break;
2486 }
2487 BUG_ON(ret > 0);
2488
2489 if (!upper->eb) {
2490 upper->eb = path->nodes[upper->level];
2491 path->nodes[upper->level] = NULL;
2492 } else {
2493 BUG_ON(upper->eb != path->nodes[upper->level]);
2494 }
2495
2496 upper->locked = 1;
2497 path->locks[upper->level] = 0;
2498
2499 slot = path->slots[upper->level];
2500 btrfs_release_path(NULL, path);
2501 } else {
2502 ret = btrfs_bin_search(upper->eb, key, upper->level,
2503 &slot);
2504 BUG_ON(ret);
2505 }
2506
2507 bytenr = btrfs_node_blockptr(upper->eb, slot);
2508 if (lowest) {
2509 BUG_ON(bytenr != node->bytenr);
2510 } else {
2511 if (node->eb->start == bytenr)
2512 goto next;
2513 }
2514
2515 blocksize = btrfs_level_size(root, node->level);
2516 generation = btrfs_node_ptr_generation(upper->eb, slot);
2517 eb = read_tree_block(root, bytenr, blocksize, generation);
2518 if (!eb) {
2519 err = -EIO;
2520 goto next;
2521 }
2522 btrfs_tree_lock(eb);
2523 btrfs_set_lock_blocking(eb);
2524
2525 if (!node->eb) {
2526 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2527 slot, &eb);
2528 btrfs_tree_unlock(eb);
2529 free_extent_buffer(eb);
2530 if (ret < 0) {
2531 err = ret;
2532 goto next;
2533 }
2534 BUG_ON(node->eb != eb);
2535 } else {
2536 btrfs_set_node_blockptr(upper->eb, slot,
2537 node->eb->start);
2538 btrfs_set_node_ptr_generation(upper->eb, slot,
2539 trans->transid);
2540 btrfs_mark_buffer_dirty(upper->eb);
2541
2542 ret = btrfs_inc_extent_ref(trans, root,
2543 node->eb->start, blocksize,
2544 upper->eb->start,
2545 btrfs_header_owner(upper->eb),
2546 node->level, 0);
2547 BUG_ON(ret);
2548
2549 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2550 BUG_ON(ret);
2551 }
2552 next:
2553 if (!upper->pending)
2554 drop_node_buffer(upper);
2555 else
2556 unlock_node_buffer(upper);
2557 if (err)
2558 break;
2559 }
2560
2561 if (!err && node->pending) {
2562 drop_node_buffer(node);
2563 list_move_tail(&node->list, &rc->backref_cache.changed);
2564 node->pending = 0;
2565 }
2566
2567 path->lowest_level = 0;
2568 BUG_ON(err == -ENOSPC);
2569 return err;
2570 }
2571
2572 static int link_to_upper(struct btrfs_trans_handle *trans,
2573 struct reloc_control *rc,
2574 struct backref_node *node,
2575 struct btrfs_path *path)
2576 {
2577 struct btrfs_key key;
2578
2579 btrfs_node_key_to_cpu(node->eb, &key, 0);
2580 return do_relocation(trans, rc, node, &key, path, 0);
2581 }
2582
2583 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2584 struct reloc_control *rc,
2585 struct btrfs_path *path, int err)
2586 {
2587 LIST_HEAD(list);
2588 struct backref_cache *cache = &rc->backref_cache;
2589 struct backref_node *node;
2590 int level;
2591 int ret;
2592
2593 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2594 while (!list_empty(&cache->pending[level])) {
2595 node = list_entry(cache->pending[level].next,
2596 struct backref_node, list);
2597 list_move_tail(&node->list, &list);
2598 BUG_ON(!node->pending);
2599
2600 if (!err) {
2601 ret = link_to_upper(trans, rc, node, path);
2602 if (ret < 0)
2603 err = ret;
2604 }
2605 }
2606 list_splice_init(&list, &cache->pending[level]);
2607 }
2608 return err;
2609 }
2610
2611 static void mark_block_processed(struct reloc_control *rc,
2612 u64 bytenr, u32 blocksize)
2613 {
2614 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2615 EXTENT_DIRTY, GFP_NOFS);
2616 }
2617
2618 static void __mark_block_processed(struct reloc_control *rc,
2619 struct backref_node *node)
2620 {
2621 u32 blocksize;
2622 if (node->level == 0 ||
2623 in_block_group(node->bytenr, rc->block_group)) {
2624 blocksize = btrfs_level_size(rc->extent_root, node->level);
2625 mark_block_processed(rc, node->bytenr, blocksize);
2626 }
2627 node->processed = 1;
2628 }
2629
2630 /*
2631 * mark a block and all blocks directly/indirectly reference the block
2632 * as processed.
2633 */
2634 static void update_processed_blocks(struct reloc_control *rc,
2635 struct backref_node *node)
2636 {
2637 struct backref_node *next = node;
2638 struct backref_edge *edge;
2639 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2640 int index = 0;
2641
2642 while (next) {
2643 cond_resched();
2644 while (1) {
2645 if (next->processed)
2646 break;
2647
2648 __mark_block_processed(rc, next);
2649
2650 if (list_empty(&next->upper))
2651 break;
2652
2653 edge = list_entry(next->upper.next,
2654 struct backref_edge, list[LOWER]);
2655 edges[index++] = edge;
2656 next = edge->node[UPPER];
2657 }
2658 next = walk_down_backref(edges, &index);
2659 }
2660 }
2661
2662 static int tree_block_processed(u64 bytenr, u32 blocksize,
2663 struct reloc_control *rc)
2664 {
2665 if (test_range_bit(&rc->processed_blocks, bytenr,
2666 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2667 return 1;
2668 return 0;
2669 }
2670
2671 static int get_tree_block_key(struct reloc_control *rc,
2672 struct tree_block *block)
2673 {
2674 struct extent_buffer *eb;
2675
2676 BUG_ON(block->key_ready);
2677 eb = read_tree_block(rc->extent_root, block->bytenr,
2678 block->key.objectid, block->key.offset);
2679 BUG_ON(!eb);
2680 WARN_ON(btrfs_header_level(eb) != block->level);
2681 if (block->level == 0)
2682 btrfs_item_key_to_cpu(eb, &block->key, 0);
2683 else
2684 btrfs_node_key_to_cpu(eb, &block->key, 0);
2685 free_extent_buffer(eb);
2686 block->key_ready = 1;
2687 return 0;
2688 }
2689
2690 static int reada_tree_block(struct reloc_control *rc,
2691 struct tree_block *block)
2692 {
2693 BUG_ON(block->key_ready);
2694 readahead_tree_block(rc->extent_root, block->bytenr,
2695 block->key.objectid, block->key.offset);
2696 return 0;
2697 }
2698
2699 /*
2700 * helper function to relocate a tree block
2701 */
2702 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2703 struct reloc_control *rc,
2704 struct backref_node *node,
2705 struct btrfs_key *key,
2706 struct btrfs_path *path)
2707 {
2708 struct btrfs_root *root;
2709 int release = 0;
2710 int ret = 0;
2711
2712 if (!node)
2713 return 0;
2714
2715 BUG_ON(node->processed);
2716 root = select_one_root(trans, node);
2717 if (root == ERR_PTR(-ENOENT)) {
2718 update_processed_blocks(rc, node);
2719 goto out;
2720 }
2721
2722 if (!root || root->ref_cows) {
2723 ret = reserve_metadata_space(trans, rc, node);
2724 if (ret)
2725 goto out;
2726 release = 1;
2727 }
2728
2729 if (root) {
2730 if (root->ref_cows) {
2731 BUG_ON(node->new_bytenr);
2732 BUG_ON(!list_empty(&node->list));
2733 btrfs_record_root_in_trans(trans, root);
2734 root = root->reloc_root;
2735 node->new_bytenr = root->node->start;
2736 node->root = root;
2737 list_add_tail(&node->list, &rc->backref_cache.changed);
2738 } else {
2739 path->lowest_level = node->level;
2740 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2741 btrfs_release_path(root, path);
2742 if (ret > 0)
2743 ret = 0;
2744 }
2745 if (!ret)
2746 update_processed_blocks(rc, node);
2747 } else {
2748 ret = do_relocation(trans, rc, node, key, path, 1);
2749 }
2750 out:
2751 if (ret || node->level == 0 || node->cowonly) {
2752 if (release)
2753 release_metadata_space(rc, node);
2754 remove_backref_node(&rc->backref_cache, node);
2755 }
2756 return ret;
2757 }
2758
2759 /*
2760 * relocate a list of blocks
2761 */
2762 static noinline_for_stack
2763 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2764 struct reloc_control *rc, struct rb_root *blocks)
2765 {
2766 struct backref_node *node;
2767 struct btrfs_path *path;
2768 struct tree_block *block;
2769 struct rb_node *rb_node;
2770 int ret;
2771 int err = 0;
2772
2773 path = btrfs_alloc_path();
2774 if (!path)
2775 return -ENOMEM;
2776
2777 rb_node = rb_first(blocks);
2778 while (rb_node) {
2779 block = rb_entry(rb_node, struct tree_block, rb_node);
2780 if (!block->key_ready)
2781 reada_tree_block(rc, block);
2782 rb_node = rb_next(rb_node);
2783 }
2784
2785 rb_node = rb_first(blocks);
2786 while (rb_node) {
2787 block = rb_entry(rb_node, struct tree_block, rb_node);
2788 if (!block->key_ready)
2789 get_tree_block_key(rc, block);
2790 rb_node = rb_next(rb_node);
2791 }
2792
2793 rb_node = rb_first(blocks);
2794 while (rb_node) {
2795 block = rb_entry(rb_node, struct tree_block, rb_node);
2796
2797 node = build_backref_tree(rc, &block->key,
2798 block->level, block->bytenr);
2799 if (IS_ERR(node)) {
2800 err = PTR_ERR(node);
2801 goto out;
2802 }
2803
2804 ret = relocate_tree_block(trans, rc, node, &block->key,
2805 path);
2806 if (ret < 0) {
2807 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2808 err = ret;
2809 goto out;
2810 }
2811 rb_node = rb_next(rb_node);
2812 }
2813 out:
2814 free_block_list(blocks);
2815 err = finish_pending_nodes(trans, rc, path, err);
2816
2817 btrfs_free_path(path);
2818 return err;
2819 }
2820
2821 static noinline_for_stack
2822 int prealloc_file_extent_cluster(struct inode *inode,
2823 struct file_extent_cluster *cluster)
2824 {
2825 u64 alloc_hint = 0;
2826 u64 start;
2827 u64 end;
2828 u64 offset = BTRFS_I(inode)->index_cnt;
2829 u64 num_bytes;
2830 int nr = 0;
2831 int ret = 0;
2832
2833 BUG_ON(cluster->start != cluster->boundary[0]);
2834 mutex_lock(&inode->i_mutex);
2835
2836 ret = btrfs_check_data_free_space(inode, cluster->end +
2837 1 - cluster->start);
2838 if (ret)
2839 goto out;
2840
2841 while (nr < cluster->nr) {
2842 start = cluster->boundary[nr] - offset;
2843 if (nr + 1 < cluster->nr)
2844 end = cluster->boundary[nr + 1] - 1 - offset;
2845 else
2846 end = cluster->end - offset;
2847
2848 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2849 num_bytes = end + 1 - start;
2850 ret = btrfs_prealloc_file_range(inode, 0, start,
2851 num_bytes, num_bytes,
2852 end + 1, &alloc_hint);
2853 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2854 if (ret)
2855 break;
2856 nr++;
2857 }
2858 btrfs_free_reserved_data_space(inode, cluster->end +
2859 1 - cluster->start);
2860 out:
2861 mutex_unlock(&inode->i_mutex);
2862 return ret;
2863 }
2864
2865 static noinline_for_stack
2866 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
2867 u64 block_start)
2868 {
2869 struct btrfs_root *root = BTRFS_I(inode)->root;
2870 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2871 struct extent_map *em;
2872 int ret = 0;
2873
2874 em = alloc_extent_map(GFP_NOFS);
2875 if (!em)
2876 return -ENOMEM;
2877
2878 em->start = start;
2879 em->len = end + 1 - start;
2880 em->block_len = em->len;
2881 em->block_start = block_start;
2882 em->bdev = root->fs_info->fs_devices->latest_bdev;
2883 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2884
2885 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2886 while (1) {
2887 write_lock(&em_tree->lock);
2888 ret = add_extent_mapping(em_tree, em);
2889 write_unlock(&em_tree->lock);
2890 if (ret != -EEXIST) {
2891 free_extent_map(em);
2892 break;
2893 }
2894 btrfs_drop_extent_cache(inode, start, end, 0);
2895 }
2896 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2897 return ret;
2898 }
2899
2900 static int relocate_file_extent_cluster(struct inode *inode,
2901 struct file_extent_cluster *cluster)
2902 {
2903 u64 page_start;
2904 u64 page_end;
2905 u64 offset = BTRFS_I(inode)->index_cnt;
2906 unsigned long index;
2907 unsigned long last_index;
2908 struct page *page;
2909 struct file_ra_state *ra;
2910 int nr = 0;
2911 int ret = 0;
2912
2913 if (!cluster->nr)
2914 return 0;
2915
2916 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2917 if (!ra)
2918 return -ENOMEM;
2919
2920 ret = prealloc_file_extent_cluster(inode, cluster);
2921 if (ret)
2922 goto out;
2923
2924 file_ra_state_init(ra, inode->i_mapping);
2925
2926 ret = setup_extent_mapping(inode, cluster->start - offset,
2927 cluster->end - offset, cluster->start);
2928 if (ret)
2929 goto out;
2930
2931 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
2932 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
2933 while (index <= last_index) {
2934 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
2935 if (ret)
2936 goto out;
2937
2938 page = find_lock_page(inode->i_mapping, index);
2939 if (!page) {
2940 page_cache_sync_readahead(inode->i_mapping,
2941 ra, NULL, index,
2942 last_index + 1 - index);
2943 page = grab_cache_page(inode->i_mapping, index);
2944 if (!page) {
2945 btrfs_delalloc_release_metadata(inode,
2946 PAGE_CACHE_SIZE);
2947 ret = -ENOMEM;
2948 goto out;
2949 }
2950 }
2951
2952 if (PageReadahead(page)) {
2953 page_cache_async_readahead(inode->i_mapping,
2954 ra, NULL, page, index,
2955 last_index + 1 - index);
2956 }
2957
2958 if (!PageUptodate(page)) {
2959 btrfs_readpage(NULL, page);
2960 lock_page(page);
2961 if (!PageUptodate(page)) {
2962 unlock_page(page);
2963 page_cache_release(page);
2964 btrfs_delalloc_release_metadata(inode,
2965 PAGE_CACHE_SIZE);
2966 ret = -EIO;
2967 goto out;
2968 }
2969 }
2970
2971 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2972 page_end = page_start + PAGE_CACHE_SIZE - 1;
2973
2974 lock_extent(&BTRFS_I(inode)->io_tree,
2975 page_start, page_end, GFP_NOFS);
2976
2977 set_page_extent_mapped(page);
2978
2979 if (nr < cluster->nr &&
2980 page_start + offset == cluster->boundary[nr]) {
2981 set_extent_bits(&BTRFS_I(inode)->io_tree,
2982 page_start, page_end,
2983 EXTENT_BOUNDARY, GFP_NOFS);
2984 nr++;
2985 }
2986
2987 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
2988 set_page_dirty(page);
2989
2990 unlock_extent(&BTRFS_I(inode)->io_tree,
2991 page_start, page_end, GFP_NOFS);
2992 unlock_page(page);
2993 page_cache_release(page);
2994
2995 index++;
2996 balance_dirty_pages_ratelimited(inode->i_mapping);
2997 btrfs_throttle(BTRFS_I(inode)->root);
2998 }
2999 WARN_ON(nr != cluster->nr);
3000 out:
3001 kfree(ra);
3002 return ret;
3003 }
3004
3005 static noinline_for_stack
3006 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3007 struct file_extent_cluster *cluster)
3008 {
3009 int ret;
3010
3011 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3012 ret = relocate_file_extent_cluster(inode, cluster);
3013 if (ret)
3014 return ret;
3015 cluster->nr = 0;
3016 }
3017
3018 if (!cluster->nr)
3019 cluster->start = extent_key->objectid;
3020 else
3021 BUG_ON(cluster->nr >= MAX_EXTENTS);
3022 cluster->end = extent_key->objectid + extent_key->offset - 1;
3023 cluster->boundary[cluster->nr] = extent_key->objectid;
3024 cluster->nr++;
3025
3026 if (cluster->nr >= MAX_EXTENTS) {
3027 ret = relocate_file_extent_cluster(inode, cluster);
3028 if (ret)
3029 return ret;
3030 cluster->nr = 0;
3031 }
3032 return 0;
3033 }
3034
3035 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3036 static int get_ref_objectid_v0(struct reloc_control *rc,
3037 struct btrfs_path *path,
3038 struct btrfs_key *extent_key,
3039 u64 *ref_objectid, int *path_change)
3040 {
3041 struct btrfs_key key;
3042 struct extent_buffer *leaf;
3043 struct btrfs_extent_ref_v0 *ref0;
3044 int ret;
3045 int slot;
3046
3047 leaf = path->nodes[0];
3048 slot = path->slots[0];
3049 while (1) {
3050 if (slot >= btrfs_header_nritems(leaf)) {
3051 ret = btrfs_next_leaf(rc->extent_root, path);
3052 if (ret < 0)
3053 return ret;
3054 BUG_ON(ret > 0);
3055 leaf = path->nodes[0];
3056 slot = path->slots[0];
3057 if (path_change)
3058 *path_change = 1;
3059 }
3060 btrfs_item_key_to_cpu(leaf, &key, slot);
3061 if (key.objectid != extent_key->objectid)
3062 return -ENOENT;
3063
3064 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3065 slot++;
3066 continue;
3067 }
3068 ref0 = btrfs_item_ptr(leaf, slot,
3069 struct btrfs_extent_ref_v0);
3070 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3071 break;
3072 }
3073 return 0;
3074 }
3075 #endif
3076
3077 /*
3078 * helper to add a tree block to the list.
3079 * the major work is getting the generation and level of the block
3080 */
3081 static int add_tree_block(struct reloc_control *rc,
3082 struct btrfs_key *extent_key,
3083 struct btrfs_path *path,
3084 struct rb_root *blocks)
3085 {
3086 struct extent_buffer *eb;
3087 struct btrfs_extent_item *ei;
3088 struct btrfs_tree_block_info *bi;
3089 struct tree_block *block;
3090 struct rb_node *rb_node;
3091 u32 item_size;
3092 int level = -1;
3093 int generation;
3094
3095 eb = path->nodes[0];
3096 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3097
3098 if (item_size >= sizeof(*ei) + sizeof(*bi)) {
3099 ei = btrfs_item_ptr(eb, path->slots[0],
3100 struct btrfs_extent_item);
3101 bi = (struct btrfs_tree_block_info *)(ei + 1);
3102 generation = btrfs_extent_generation(eb, ei);
3103 level = btrfs_tree_block_level(eb, bi);
3104 } else {
3105 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3106 u64 ref_owner;
3107 int ret;
3108
3109 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3110 ret = get_ref_objectid_v0(rc, path, extent_key,
3111 &ref_owner, NULL);
3112 if (ret < 0)
3113 return ret;
3114 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3115 level = (int)ref_owner;
3116 /* FIXME: get real generation */
3117 generation = 0;
3118 #else
3119 BUG();
3120 #endif
3121 }
3122
3123 btrfs_release_path(rc->extent_root, path);
3124
3125 BUG_ON(level == -1);
3126
3127 block = kmalloc(sizeof(*block), GFP_NOFS);
3128 if (!block)
3129 return -ENOMEM;
3130
3131 block->bytenr = extent_key->objectid;
3132 block->key.objectid = extent_key->offset;
3133 block->key.offset = generation;
3134 block->level = level;
3135 block->key_ready = 0;
3136
3137 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3138 BUG_ON(rb_node);
3139
3140 return 0;
3141 }
3142
3143 /*
3144 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3145 */
3146 static int __add_tree_block(struct reloc_control *rc,
3147 u64 bytenr, u32 blocksize,
3148 struct rb_root *blocks)
3149 {
3150 struct btrfs_path *path;
3151 struct btrfs_key key;
3152 int ret;
3153
3154 if (tree_block_processed(bytenr, blocksize, rc))
3155 return 0;
3156
3157 if (tree_search(blocks, bytenr))
3158 return 0;
3159
3160 path = btrfs_alloc_path();
3161 if (!path)
3162 return -ENOMEM;
3163
3164 key.objectid = bytenr;
3165 key.type = BTRFS_EXTENT_ITEM_KEY;
3166 key.offset = blocksize;
3167
3168 path->search_commit_root = 1;
3169 path->skip_locking = 1;
3170 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3171 if (ret < 0)
3172 goto out;
3173 BUG_ON(ret);
3174
3175 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3176 ret = add_tree_block(rc, &key, path, blocks);
3177 out:
3178 btrfs_free_path(path);
3179 return ret;
3180 }
3181
3182 /*
3183 * helper to check if the block use full backrefs for pointers in it
3184 */
3185 static int block_use_full_backref(struct reloc_control *rc,
3186 struct extent_buffer *eb)
3187 {
3188 u64 flags;
3189 int ret;
3190
3191 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3192 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3193 return 1;
3194
3195 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3196 eb->start, eb->len, NULL, &flags);
3197 BUG_ON(ret);
3198
3199 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3200 ret = 1;
3201 else
3202 ret = 0;
3203 return ret;
3204 }
3205
3206 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3207 struct inode *inode, u64 ino)
3208 {
3209 struct btrfs_key key;
3210 struct btrfs_path *path;
3211 struct btrfs_root *root = fs_info->tree_root;
3212 struct btrfs_trans_handle *trans;
3213 unsigned long nr;
3214 int ret = 0;
3215
3216 if (inode)
3217 goto truncate;
3218
3219 key.objectid = ino;
3220 key.type = BTRFS_INODE_ITEM_KEY;
3221 key.offset = 0;
3222
3223 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3224 if (!inode || IS_ERR(inode) || is_bad_inode(inode)) {
3225 if (inode && !IS_ERR(inode))
3226 iput(inode);
3227 return -ENOENT;
3228 }
3229
3230 truncate:
3231 path = btrfs_alloc_path();
3232 if (!path) {
3233 ret = -ENOMEM;
3234 goto out;
3235 }
3236
3237 trans = btrfs_join_transaction(root, 0);
3238 if (IS_ERR(trans)) {
3239 btrfs_free_path(path);
3240 ret = PTR_ERR(trans);
3241 goto out;
3242 }
3243
3244 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
3245
3246 btrfs_free_path(path);
3247 nr = trans->blocks_used;
3248 btrfs_end_transaction(trans, root);
3249 btrfs_btree_balance_dirty(root, nr);
3250 out:
3251 iput(inode);
3252 return ret;
3253 }
3254
3255 /*
3256 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3257 * this function scans fs tree to find blocks reference the data extent
3258 */
3259 static int find_data_references(struct reloc_control *rc,
3260 struct btrfs_key *extent_key,
3261 struct extent_buffer *leaf,
3262 struct btrfs_extent_data_ref *ref,
3263 struct rb_root *blocks)
3264 {
3265 struct btrfs_path *path;
3266 struct tree_block *block;
3267 struct btrfs_root *root;
3268 struct btrfs_file_extent_item *fi;
3269 struct rb_node *rb_node;
3270 struct btrfs_key key;
3271 u64 ref_root;
3272 u64 ref_objectid;
3273 u64 ref_offset;
3274 u32 ref_count;
3275 u32 nritems;
3276 int err = 0;
3277 int added = 0;
3278 int counted;
3279 int ret;
3280
3281 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3282 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3283 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3284 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3285
3286 /*
3287 * This is an extent belonging to the free space cache, lets just delete
3288 * it and redo the search.
3289 */
3290 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3291 ret = delete_block_group_cache(rc->extent_root->fs_info,
3292 NULL, ref_objectid);
3293 if (ret != -ENOENT)
3294 return ret;
3295 ret = 0;
3296 }
3297
3298 path = btrfs_alloc_path();
3299 if (!path)
3300 return -ENOMEM;
3301
3302 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3303 if (IS_ERR(root)) {
3304 err = PTR_ERR(root);
3305 goto out;
3306 }
3307
3308 key.objectid = ref_objectid;
3309 key.offset = ref_offset;
3310 key.type = BTRFS_EXTENT_DATA_KEY;
3311
3312 path->search_commit_root = 1;
3313 path->skip_locking = 1;
3314 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3315 if (ret < 0) {
3316 err = ret;
3317 goto out;
3318 }
3319
3320 leaf = path->nodes[0];
3321 nritems = btrfs_header_nritems(leaf);
3322 /*
3323 * the references in tree blocks that use full backrefs
3324 * are not counted in
3325 */
3326 if (block_use_full_backref(rc, leaf))
3327 counted = 0;
3328 else
3329 counted = 1;
3330 rb_node = tree_search(blocks, leaf->start);
3331 if (rb_node) {
3332 if (counted)
3333 added = 1;
3334 else
3335 path->slots[0] = nritems;
3336 }
3337
3338 while (ref_count > 0) {
3339 while (path->slots[0] >= nritems) {
3340 ret = btrfs_next_leaf(root, path);
3341 if (ret < 0) {
3342 err = ret;
3343 goto out;
3344 }
3345 if (ret > 0) {
3346 WARN_ON(1);
3347 goto out;
3348 }
3349
3350 leaf = path->nodes[0];
3351 nritems = btrfs_header_nritems(leaf);
3352 added = 0;
3353
3354 if (block_use_full_backref(rc, leaf))
3355 counted = 0;
3356 else
3357 counted = 1;
3358 rb_node = tree_search(blocks, leaf->start);
3359 if (rb_node) {
3360 if (counted)
3361 added = 1;
3362 else
3363 path->slots[0] = nritems;
3364 }
3365 }
3366
3367 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3368 if (key.objectid != ref_objectid ||
3369 key.type != BTRFS_EXTENT_DATA_KEY) {
3370 WARN_ON(1);
3371 break;
3372 }
3373
3374 fi = btrfs_item_ptr(leaf, path->slots[0],
3375 struct btrfs_file_extent_item);
3376
3377 if (btrfs_file_extent_type(leaf, fi) ==
3378 BTRFS_FILE_EXTENT_INLINE)
3379 goto next;
3380
3381 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3382 extent_key->objectid)
3383 goto next;
3384
3385 key.offset -= btrfs_file_extent_offset(leaf, fi);
3386 if (key.offset != ref_offset)
3387 goto next;
3388
3389 if (counted)
3390 ref_count--;
3391 if (added)
3392 goto next;
3393
3394 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3395 block = kmalloc(sizeof(*block), GFP_NOFS);
3396 if (!block) {
3397 err = -ENOMEM;
3398 break;
3399 }
3400 block->bytenr = leaf->start;
3401 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3402 block->level = 0;
3403 block->key_ready = 1;
3404 rb_node = tree_insert(blocks, block->bytenr,
3405 &block->rb_node);
3406 BUG_ON(rb_node);
3407 }
3408 if (counted)
3409 added = 1;
3410 else
3411 path->slots[0] = nritems;
3412 next:
3413 path->slots[0]++;
3414
3415 }
3416 out:
3417 btrfs_free_path(path);
3418 return err;
3419 }
3420
3421 /*
3422 * hepler to find all tree blocks that reference a given data extent
3423 */
3424 static noinline_for_stack
3425 int add_data_references(struct reloc_control *rc,
3426 struct btrfs_key *extent_key,
3427 struct btrfs_path *path,
3428 struct rb_root *blocks)
3429 {
3430 struct btrfs_key key;
3431 struct extent_buffer *eb;
3432 struct btrfs_extent_data_ref *dref;
3433 struct btrfs_extent_inline_ref *iref;
3434 unsigned long ptr;
3435 unsigned long end;
3436 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3437 int ret;
3438 int err = 0;
3439
3440 eb = path->nodes[0];
3441 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3442 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3443 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3444 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3445 ptr = end;
3446 else
3447 #endif
3448 ptr += sizeof(struct btrfs_extent_item);
3449
3450 while (ptr < end) {
3451 iref = (struct btrfs_extent_inline_ref *)ptr;
3452 key.type = btrfs_extent_inline_ref_type(eb, iref);
3453 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3454 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3455 ret = __add_tree_block(rc, key.offset, blocksize,
3456 blocks);
3457 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3458 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3459 ret = find_data_references(rc, extent_key,
3460 eb, dref, blocks);
3461 } else {
3462 BUG();
3463 }
3464 ptr += btrfs_extent_inline_ref_size(key.type);
3465 }
3466 WARN_ON(ptr > end);
3467
3468 while (1) {
3469 cond_resched();
3470 eb = path->nodes[0];
3471 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3472 ret = btrfs_next_leaf(rc->extent_root, path);
3473 if (ret < 0) {
3474 err = ret;
3475 break;
3476 }
3477 if (ret > 0)
3478 break;
3479 eb = path->nodes[0];
3480 }
3481
3482 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3483 if (key.objectid != extent_key->objectid)
3484 break;
3485
3486 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3487 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3488 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3489 #else
3490 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3491 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3492 #endif
3493 ret = __add_tree_block(rc, key.offset, blocksize,
3494 blocks);
3495 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3496 dref = btrfs_item_ptr(eb, path->slots[0],
3497 struct btrfs_extent_data_ref);
3498 ret = find_data_references(rc, extent_key,
3499 eb, dref, blocks);
3500 } else {
3501 ret = 0;
3502 }
3503 if (ret) {
3504 err = ret;
3505 break;
3506 }
3507 path->slots[0]++;
3508 }
3509 btrfs_release_path(rc->extent_root, path);
3510 if (err)
3511 free_block_list(blocks);
3512 return err;
3513 }
3514
3515 /*
3516 * hepler to find next unprocessed extent
3517 */
3518 static noinline_for_stack
3519 int find_next_extent(struct btrfs_trans_handle *trans,
3520 struct reloc_control *rc, struct btrfs_path *path,
3521 struct btrfs_key *extent_key)
3522 {
3523 struct btrfs_key key;
3524 struct extent_buffer *leaf;
3525 u64 start, end, last;
3526 int ret;
3527
3528 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3529 while (1) {
3530 cond_resched();
3531 if (rc->search_start >= last) {
3532 ret = 1;
3533 break;
3534 }
3535
3536 key.objectid = rc->search_start;
3537 key.type = BTRFS_EXTENT_ITEM_KEY;
3538 key.offset = 0;
3539
3540 path->search_commit_root = 1;
3541 path->skip_locking = 1;
3542 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3543 0, 0);
3544 if (ret < 0)
3545 break;
3546 next:
3547 leaf = path->nodes[0];
3548 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3549 ret = btrfs_next_leaf(rc->extent_root, path);
3550 if (ret != 0)
3551 break;
3552 leaf = path->nodes[0];
3553 }
3554
3555 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3556 if (key.objectid >= last) {
3557 ret = 1;
3558 break;
3559 }
3560
3561 if (key.type != BTRFS_EXTENT_ITEM_KEY ||
3562 key.objectid + key.offset <= rc->search_start) {
3563 path->slots[0]++;
3564 goto next;
3565 }
3566
3567 ret = find_first_extent_bit(&rc->processed_blocks,
3568 key.objectid, &start, &end,
3569 EXTENT_DIRTY);
3570
3571 if (ret == 0 && start <= key.objectid) {
3572 btrfs_release_path(rc->extent_root, path);
3573 rc->search_start = end + 1;
3574 } else {
3575 rc->search_start = key.objectid + key.offset;
3576 memcpy(extent_key, &key, sizeof(key));
3577 return 0;
3578 }
3579 }
3580 btrfs_release_path(rc->extent_root, path);
3581 return ret;
3582 }
3583
3584 static void set_reloc_control(struct reloc_control *rc)
3585 {
3586 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3587 mutex_lock(&fs_info->trans_mutex);
3588 fs_info->reloc_ctl = rc;
3589 mutex_unlock(&fs_info->trans_mutex);
3590 }
3591
3592 static void unset_reloc_control(struct reloc_control *rc)
3593 {
3594 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3595 mutex_lock(&fs_info->trans_mutex);
3596 fs_info->reloc_ctl = NULL;
3597 mutex_unlock(&fs_info->trans_mutex);
3598 }
3599
3600 static int check_extent_flags(u64 flags)
3601 {
3602 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3603 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3604 return 1;
3605 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3606 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3607 return 1;
3608 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3609 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3610 return 1;
3611 return 0;
3612 }
3613
3614 static noinline_for_stack
3615 int prepare_to_relocate(struct reloc_control *rc)
3616 {
3617 struct btrfs_trans_handle *trans;
3618 int ret;
3619
3620 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root);
3621 if (!rc->block_rsv)
3622 return -ENOMEM;
3623
3624 /*
3625 * reserve some space for creating reloc trees.
3626 * btrfs_init_reloc_root will use them when there
3627 * is no reservation in transaction handle.
3628 */
3629 ret = btrfs_block_rsv_add(NULL, rc->extent_root, rc->block_rsv,
3630 rc->extent_root->nodesize * 256);
3631 if (ret)
3632 return ret;
3633
3634 rc->block_rsv->refill_used = 1;
3635 btrfs_add_durable_block_rsv(rc->extent_root->fs_info, rc->block_rsv);
3636
3637 memset(&rc->cluster, 0, sizeof(rc->cluster));
3638 rc->search_start = rc->block_group->key.objectid;
3639 rc->extents_found = 0;
3640 rc->nodes_relocated = 0;
3641 rc->merging_rsv_size = 0;
3642
3643 rc->create_reloc_tree = 1;
3644 set_reloc_control(rc);
3645
3646 trans = btrfs_join_transaction(rc->extent_root, 1);
3647 BUG_ON(IS_ERR(trans));
3648 btrfs_commit_transaction(trans, rc->extent_root);
3649 return 0;
3650 }
3651
3652 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3653 {
3654 struct rb_root blocks = RB_ROOT;
3655 struct btrfs_key key;
3656 struct btrfs_trans_handle *trans = NULL;
3657 struct btrfs_path *path;
3658 struct btrfs_extent_item *ei;
3659 unsigned long nr;
3660 u64 flags;
3661 u32 item_size;
3662 int ret;
3663 int err = 0;
3664 int progress = 0;
3665
3666 path = btrfs_alloc_path();
3667 if (!path)
3668 return -ENOMEM;
3669
3670 ret = prepare_to_relocate(rc);
3671 if (ret) {
3672 err = ret;
3673 goto out_free;
3674 }
3675
3676 while (1) {
3677 progress++;
3678 trans = btrfs_start_transaction(rc->extent_root, 0);
3679 BUG_ON(IS_ERR(trans));
3680 restart:
3681 if (update_backref_cache(trans, &rc->backref_cache)) {
3682 btrfs_end_transaction(trans, rc->extent_root);
3683 continue;
3684 }
3685
3686 ret = find_next_extent(trans, rc, path, &key);
3687 if (ret < 0)
3688 err = ret;
3689 if (ret != 0)
3690 break;
3691
3692 rc->extents_found++;
3693
3694 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3695 struct btrfs_extent_item);
3696 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3697 if (item_size >= sizeof(*ei)) {
3698 flags = btrfs_extent_flags(path->nodes[0], ei);
3699 ret = check_extent_flags(flags);
3700 BUG_ON(ret);
3701
3702 } else {
3703 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3704 u64 ref_owner;
3705 int path_change = 0;
3706
3707 BUG_ON(item_size !=
3708 sizeof(struct btrfs_extent_item_v0));
3709 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3710 &path_change);
3711 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3712 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3713 else
3714 flags = BTRFS_EXTENT_FLAG_DATA;
3715
3716 if (path_change) {
3717 btrfs_release_path(rc->extent_root, path);
3718
3719 path->search_commit_root = 1;
3720 path->skip_locking = 1;
3721 ret = btrfs_search_slot(NULL, rc->extent_root,
3722 &key, path, 0, 0);
3723 if (ret < 0) {
3724 err = ret;
3725 break;
3726 }
3727 BUG_ON(ret > 0);
3728 }
3729 #else
3730 BUG();
3731 #endif
3732 }
3733
3734 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3735 ret = add_tree_block(rc, &key, path, &blocks);
3736 } else if (rc->stage == UPDATE_DATA_PTRS &&
3737 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3738 ret = add_data_references(rc, &key, path, &blocks);
3739 } else {
3740 btrfs_release_path(rc->extent_root, path);
3741 ret = 0;
3742 }
3743 if (ret < 0) {
3744 err = ret;
3745 break;
3746 }
3747
3748 if (!RB_EMPTY_ROOT(&blocks)) {
3749 ret = relocate_tree_blocks(trans, rc, &blocks);
3750 if (ret < 0) {
3751 if (ret != -EAGAIN) {
3752 err = ret;
3753 break;
3754 }
3755 rc->extents_found--;
3756 rc->search_start = key.objectid;
3757 }
3758 }
3759
3760 ret = btrfs_block_rsv_check(trans, rc->extent_root,
3761 rc->block_rsv, 0, 5);
3762 if (ret < 0) {
3763 if (ret != -EAGAIN) {
3764 err = ret;
3765 WARN_ON(1);
3766 break;
3767 }
3768 rc->commit_transaction = 1;
3769 }
3770
3771 if (rc->commit_transaction) {
3772 rc->commit_transaction = 0;
3773 ret = btrfs_commit_transaction(trans, rc->extent_root);
3774 BUG_ON(ret);
3775 } else {
3776 nr = trans->blocks_used;
3777 btrfs_end_transaction_throttle(trans, rc->extent_root);
3778 btrfs_btree_balance_dirty(rc->extent_root, nr);
3779 }
3780 trans = NULL;
3781
3782 if (rc->stage == MOVE_DATA_EXTENTS &&
3783 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3784 rc->found_file_extent = 1;
3785 ret = relocate_data_extent(rc->data_inode,
3786 &key, &rc->cluster);
3787 if (ret < 0) {
3788 err = ret;
3789 break;
3790 }
3791 }
3792 }
3793 if (trans && progress && err == -ENOSPC) {
3794 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
3795 rc->block_group->flags);
3796 if (ret == 0) {
3797 err = 0;
3798 progress = 0;
3799 goto restart;
3800 }
3801 }
3802
3803 btrfs_release_path(rc->extent_root, path);
3804 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3805 GFP_NOFS);
3806
3807 if (trans) {
3808 nr = trans->blocks_used;
3809 btrfs_end_transaction_throttle(trans, rc->extent_root);
3810 btrfs_btree_balance_dirty(rc->extent_root, nr);
3811 }
3812
3813 if (!err) {
3814 ret = relocate_file_extent_cluster(rc->data_inode,
3815 &rc->cluster);
3816 if (ret < 0)
3817 err = ret;
3818 }
3819
3820 rc->create_reloc_tree = 0;
3821 set_reloc_control(rc);
3822
3823 backref_cache_cleanup(&rc->backref_cache);
3824 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3825
3826 err = prepare_to_merge(rc, err);
3827
3828 merge_reloc_roots(rc);
3829
3830 rc->merge_reloc_tree = 0;
3831 unset_reloc_control(rc);
3832 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3833
3834 /* get rid of pinned extents */
3835 trans = btrfs_join_transaction(rc->extent_root, 1);
3836 if (IS_ERR(trans))
3837 err = PTR_ERR(trans);
3838 else
3839 btrfs_commit_transaction(trans, rc->extent_root);
3840 out_free:
3841 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
3842 btrfs_free_path(path);
3843 return err;
3844 }
3845
3846 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3847 struct btrfs_root *root, u64 objectid)
3848 {
3849 struct btrfs_path *path;
3850 struct btrfs_inode_item *item;
3851 struct extent_buffer *leaf;
3852 int ret;
3853
3854 path = btrfs_alloc_path();
3855 if (!path)
3856 return -ENOMEM;
3857
3858 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3859 if (ret)
3860 goto out;
3861
3862 leaf = path->nodes[0];
3863 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3864 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
3865 btrfs_set_inode_generation(leaf, item, 1);
3866 btrfs_set_inode_size(leaf, item, 0);
3867 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3868 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3869 BTRFS_INODE_PREALLOC);
3870 btrfs_mark_buffer_dirty(leaf);
3871 btrfs_release_path(root, path);
3872 out:
3873 btrfs_free_path(path);
3874 return ret;
3875 }
3876
3877 /*
3878 * helper to create inode for data relocation.
3879 * the inode is in data relocation tree and its link count is 0
3880 */
3881 static noinline_for_stack
3882 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3883 struct btrfs_block_group_cache *group)
3884 {
3885 struct inode *inode = NULL;
3886 struct btrfs_trans_handle *trans;
3887 struct btrfs_root *root;
3888 struct btrfs_key key;
3889 unsigned long nr;
3890 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
3891 int err = 0;
3892
3893 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
3894 if (IS_ERR(root))
3895 return ERR_CAST(root);
3896
3897 trans = btrfs_start_transaction(root, 6);
3898 if (IS_ERR(trans))
3899 return ERR_CAST(trans);
3900
3901 err = btrfs_find_free_objectid(root, &objectid);
3902 if (err)
3903 goto out;
3904
3905 err = __insert_orphan_inode(trans, root, objectid);
3906 BUG_ON(err);
3907
3908 key.objectid = objectid;
3909 key.type = BTRFS_INODE_ITEM_KEY;
3910 key.offset = 0;
3911 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
3912 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
3913 BTRFS_I(inode)->index_cnt = group->key.objectid;
3914
3915 err = btrfs_orphan_add(trans, inode);
3916 out:
3917 nr = trans->blocks_used;
3918 btrfs_end_transaction(trans, root);
3919 btrfs_btree_balance_dirty(root, nr);
3920 if (err) {
3921 if (inode)
3922 iput(inode);
3923 inode = ERR_PTR(err);
3924 }
3925 return inode;
3926 }
3927
3928 static struct reloc_control *alloc_reloc_control(void)
3929 {
3930 struct reloc_control *rc;
3931
3932 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3933 if (!rc)
3934 return NULL;
3935
3936 INIT_LIST_HEAD(&rc->reloc_roots);
3937 backref_cache_init(&rc->backref_cache);
3938 mapping_tree_init(&rc->reloc_root_tree);
3939 extent_io_tree_init(&rc->processed_blocks, NULL, GFP_NOFS);
3940 return rc;
3941 }
3942
3943 /*
3944 * function to relocate all extents in a block group.
3945 */
3946 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
3947 {
3948 struct btrfs_fs_info *fs_info = extent_root->fs_info;
3949 struct reloc_control *rc;
3950 struct inode *inode;
3951 struct btrfs_path *path;
3952 int ret;
3953 int rw = 0;
3954 int err = 0;
3955
3956 rc = alloc_reloc_control();
3957 if (!rc)
3958 return -ENOMEM;
3959
3960 rc->extent_root = extent_root;
3961
3962 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
3963 BUG_ON(!rc->block_group);
3964
3965 if (!rc->block_group->ro) {
3966 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
3967 if (ret) {
3968 err = ret;
3969 goto out;
3970 }
3971 rw = 1;
3972 }
3973
3974 path = btrfs_alloc_path();
3975 if (!path) {
3976 err = -ENOMEM;
3977 goto out;
3978 }
3979
3980 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
3981 path);
3982 btrfs_free_path(path);
3983
3984 if (!IS_ERR(inode))
3985 ret = delete_block_group_cache(fs_info, inode, 0);
3986 else
3987 ret = PTR_ERR(inode);
3988
3989 if (ret && ret != -ENOENT) {
3990 err = ret;
3991 goto out;
3992 }
3993
3994 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
3995 if (IS_ERR(rc->data_inode)) {
3996 err = PTR_ERR(rc->data_inode);
3997 rc->data_inode = NULL;
3998 goto out;
3999 }
4000
4001 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
4002 (unsigned long long)rc->block_group->key.objectid,
4003 (unsigned long long)rc->block_group->flags);
4004
4005 btrfs_start_delalloc_inodes(fs_info->tree_root, 0);
4006 btrfs_wait_ordered_extents(fs_info->tree_root, 0, 0);
4007
4008 while (1) {
4009 mutex_lock(&fs_info->cleaner_mutex);
4010
4011 btrfs_clean_old_snapshots(fs_info->tree_root);
4012 ret = relocate_block_group(rc);
4013
4014 mutex_unlock(&fs_info->cleaner_mutex);
4015 if (ret < 0) {
4016 err = ret;
4017 goto out;
4018 }
4019
4020 if (rc->extents_found == 0)
4021 break;
4022
4023 printk(KERN_INFO "btrfs: found %llu extents\n",
4024 (unsigned long long)rc->extents_found);
4025
4026 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4027 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
4028 invalidate_mapping_pages(rc->data_inode->i_mapping,
4029 0, -1);
4030 rc->stage = UPDATE_DATA_PTRS;
4031 }
4032 }
4033
4034 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
4035 rc->block_group->key.objectid,
4036 rc->block_group->key.objectid +
4037 rc->block_group->key.offset - 1);
4038
4039 WARN_ON(rc->block_group->pinned > 0);
4040 WARN_ON(rc->block_group->reserved > 0);
4041 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4042 out:
4043 if (err && rw)
4044 btrfs_set_block_group_rw(extent_root, rc->block_group);
4045 iput(rc->data_inode);
4046 btrfs_put_block_group(rc->block_group);
4047 kfree(rc);
4048 return err;
4049 }
4050
4051 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4052 {
4053 struct btrfs_trans_handle *trans;
4054 int ret;
4055
4056 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4057 BUG_ON(IS_ERR(trans));
4058
4059 memset(&root->root_item.drop_progress, 0,
4060 sizeof(root->root_item.drop_progress));
4061 root->root_item.drop_level = 0;
4062 btrfs_set_root_refs(&root->root_item, 0);
4063 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4064 &root->root_key, &root->root_item);
4065 BUG_ON(ret);
4066
4067 ret = btrfs_end_transaction(trans, root->fs_info->tree_root);
4068 BUG_ON(ret);
4069 return 0;
4070 }
4071
4072 /*
4073 * recover relocation interrupted by system crash.
4074 *
4075 * this function resumes merging reloc trees with corresponding fs trees.
4076 * this is important for keeping the sharing of tree blocks
4077 */
4078 int btrfs_recover_relocation(struct btrfs_root *root)
4079 {
4080 LIST_HEAD(reloc_roots);
4081 struct btrfs_key key;
4082 struct btrfs_root *fs_root;
4083 struct btrfs_root *reloc_root;
4084 struct btrfs_path *path;
4085 struct extent_buffer *leaf;
4086 struct reloc_control *rc = NULL;
4087 struct btrfs_trans_handle *trans;
4088 int ret;
4089 int err = 0;
4090
4091 path = btrfs_alloc_path();
4092 if (!path)
4093 return -ENOMEM;
4094
4095 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4096 key.type = BTRFS_ROOT_ITEM_KEY;
4097 key.offset = (u64)-1;
4098
4099 while (1) {
4100 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4101 path, 0, 0);
4102 if (ret < 0) {
4103 err = ret;
4104 goto out;
4105 }
4106 if (ret > 0) {
4107 if (path->slots[0] == 0)
4108 break;
4109 path->slots[0]--;
4110 }
4111 leaf = path->nodes[0];
4112 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4113 btrfs_release_path(root->fs_info->tree_root, path);
4114
4115 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4116 key.type != BTRFS_ROOT_ITEM_KEY)
4117 break;
4118
4119 reloc_root = btrfs_read_fs_root_no_radix(root, &key);
4120 if (IS_ERR(reloc_root)) {
4121 err = PTR_ERR(reloc_root);
4122 goto out;
4123 }
4124
4125 list_add(&reloc_root->root_list, &reloc_roots);
4126
4127 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4128 fs_root = read_fs_root(root->fs_info,
4129 reloc_root->root_key.offset);
4130 if (IS_ERR(fs_root)) {
4131 ret = PTR_ERR(fs_root);
4132 if (ret != -ENOENT) {
4133 err = ret;
4134 goto out;
4135 }
4136 mark_garbage_root(reloc_root);
4137 }
4138 }
4139
4140 if (key.offset == 0)
4141 break;
4142
4143 key.offset--;
4144 }
4145 btrfs_release_path(root->fs_info->tree_root, path);
4146
4147 if (list_empty(&reloc_roots))
4148 goto out;
4149
4150 rc = alloc_reloc_control();
4151 if (!rc) {
4152 err = -ENOMEM;
4153 goto out;
4154 }
4155
4156 rc->extent_root = root->fs_info->extent_root;
4157
4158 set_reloc_control(rc);
4159
4160 trans = btrfs_join_transaction(rc->extent_root, 1);
4161 if (IS_ERR(trans)) {
4162 unset_reloc_control(rc);
4163 err = PTR_ERR(trans);
4164 goto out_free;
4165 }
4166
4167 rc->merge_reloc_tree = 1;
4168
4169 while (!list_empty(&reloc_roots)) {
4170 reloc_root = list_entry(reloc_roots.next,
4171 struct btrfs_root, root_list);
4172 list_del(&reloc_root->root_list);
4173
4174 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4175 list_add_tail(&reloc_root->root_list,
4176 &rc->reloc_roots);
4177 continue;
4178 }
4179
4180 fs_root = read_fs_root(root->fs_info,
4181 reloc_root->root_key.offset);
4182 BUG_ON(IS_ERR(fs_root));
4183
4184 __add_reloc_root(reloc_root);
4185 fs_root->reloc_root = reloc_root;
4186 }
4187
4188 btrfs_commit_transaction(trans, rc->extent_root);
4189
4190 merge_reloc_roots(rc);
4191
4192 unset_reloc_control(rc);
4193
4194 trans = btrfs_join_transaction(rc->extent_root, 1);
4195 if (IS_ERR(trans))
4196 err = PTR_ERR(trans);
4197 else
4198 btrfs_commit_transaction(trans, rc->extent_root);
4199 out_free:
4200 kfree(rc);
4201 out:
4202 while (!list_empty(&reloc_roots)) {
4203 reloc_root = list_entry(reloc_roots.next,
4204 struct btrfs_root, root_list);
4205 list_del(&reloc_root->root_list);
4206 free_extent_buffer(reloc_root->node);
4207 free_extent_buffer(reloc_root->commit_root);
4208 kfree(reloc_root);
4209 }
4210 btrfs_free_path(path);
4211
4212 if (err == 0) {
4213 /* cleanup orphan inode in data relocation tree */
4214 fs_root = read_fs_root(root->fs_info,
4215 BTRFS_DATA_RELOC_TREE_OBJECTID);
4216 if (IS_ERR(fs_root))
4217 err = PTR_ERR(fs_root);
4218 else
4219 err = btrfs_orphan_cleanup(fs_root);
4220 }
4221 return err;
4222 }
4223
4224 /*
4225 * helper to add ordered checksum for data relocation.
4226 *
4227 * cloning checksum properly handles the nodatasum extents.
4228 * it also saves CPU time to re-calculate the checksum.
4229 */
4230 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4231 {
4232 struct btrfs_ordered_sum *sums;
4233 struct btrfs_sector_sum *sector_sum;
4234 struct btrfs_ordered_extent *ordered;
4235 struct btrfs_root *root = BTRFS_I(inode)->root;
4236 size_t offset;
4237 int ret;
4238 u64 disk_bytenr;
4239 LIST_HEAD(list);
4240
4241 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4242 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4243
4244 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4245 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4246 disk_bytenr + len - 1, &list);
4247
4248 while (!list_empty(&list)) {
4249 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4250 list_del_init(&sums->list);
4251
4252 sector_sum = sums->sums;
4253 sums->bytenr = ordered->start;
4254
4255 offset = 0;
4256 while (offset < sums->len) {
4257 sector_sum->bytenr += ordered->start - disk_bytenr;
4258 sector_sum++;
4259 offset += root->sectorsize;
4260 }
4261
4262 btrfs_add_ordered_sum(inode, ordered, sums);
4263 }
4264 btrfs_put_ordered_extent(ordered);
4265 return ret;
4266 }
4267
4268 void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4269 struct btrfs_root *root, struct extent_buffer *buf,
4270 struct extent_buffer *cow)
4271 {
4272 struct reloc_control *rc;
4273 struct backref_node *node;
4274 int first_cow = 0;
4275 int level;
4276 int ret;
4277
4278 rc = root->fs_info->reloc_ctl;
4279 if (!rc)
4280 return;
4281
4282 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4283 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4284
4285 level = btrfs_header_level(buf);
4286 if (btrfs_header_generation(buf) <=
4287 btrfs_root_last_snapshot(&root->root_item))
4288 first_cow = 1;
4289
4290 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4291 rc->create_reloc_tree) {
4292 WARN_ON(!first_cow && level == 0);
4293
4294 node = rc->backref_cache.path[level];
4295 BUG_ON(node->bytenr != buf->start &&
4296 node->new_bytenr != buf->start);
4297
4298 drop_node_buffer(node);
4299 extent_buffer_get(cow);
4300 node->eb = cow;
4301 node->new_bytenr = cow->start;
4302
4303 if (!node->pending) {
4304 list_move_tail(&node->list,
4305 &rc->backref_cache.pending[level]);
4306 node->pending = 1;
4307 }
4308
4309 if (first_cow)
4310 __mark_block_processed(rc, node);
4311
4312 if (first_cow && level > 0)
4313 rc->nodes_relocated += buf->len;
4314 }
4315
4316 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) {
4317 ret = replace_file_extents(trans, rc, root, cow);
4318 BUG_ON(ret);
4319 }
4320 }
4321
4322 /*
4323 * called before creating snapshot. it calculates metadata reservation
4324 * requried for relocating tree blocks in the snapshot
4325 */
4326 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4327 struct btrfs_pending_snapshot *pending,
4328 u64 *bytes_to_reserve)
4329 {
4330 struct btrfs_root *root;
4331 struct reloc_control *rc;
4332
4333 root = pending->root;
4334 if (!root->reloc_root)
4335 return;
4336
4337 rc = root->fs_info->reloc_ctl;
4338 if (!rc->merge_reloc_tree)
4339 return;
4340
4341 root = root->reloc_root;
4342 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4343 /*
4344 * relocation is in the stage of merging trees. the space
4345 * used by merging a reloc tree is twice the size of
4346 * relocated tree nodes in the worst case. half for cowing
4347 * the reloc tree, half for cowing the fs tree. the space
4348 * used by cowing the reloc tree will be freed after the
4349 * tree is dropped. if we create snapshot, cowing the fs
4350 * tree may use more space than it frees. so we need
4351 * reserve extra space.
4352 */
4353 *bytes_to_reserve += rc->nodes_relocated;
4354 }
4355
4356 /*
4357 * called after snapshot is created. migrate block reservation
4358 * and create reloc root for the newly created snapshot
4359 */
4360 void btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4361 struct btrfs_pending_snapshot *pending)
4362 {
4363 struct btrfs_root *root = pending->root;
4364 struct btrfs_root *reloc_root;
4365 struct btrfs_root *new_root;
4366 struct reloc_control *rc;
4367 int ret;
4368
4369 if (!root->reloc_root)
4370 return;
4371
4372 rc = root->fs_info->reloc_ctl;
4373 rc->merging_rsv_size += rc->nodes_relocated;
4374
4375 if (rc->merge_reloc_tree) {
4376 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4377 rc->block_rsv,
4378 rc->nodes_relocated);
4379 BUG_ON(ret);
4380 }
4381
4382 new_root = pending->snap;
4383 reloc_root = create_reloc_root(trans, root->reloc_root,
4384 new_root->root_key.objectid);
4385
4386 __add_reloc_root(reloc_root);
4387 new_root->reloc_root = reloc_root;
4388
4389 if (rc->create_reloc_tree) {
4390 ret = clone_backref_node(trans, rc, root, reloc_root);
4391 BUG_ON(ret);
4392 }
4393 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree