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Linux 2.6.35-rc2
[linux/fpc-iii.git] / fs / btrfs / relocation.c
blob05d41e569236330cc8ed8e5e0f8b17566080791c
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
33 /*
34 * backref_node, mapping_node and tree_block start with this
35 */
36 struct tree_entry {
37 struct rb_node rb_node;
38 u64 bytenr;
39 };
40
41 /*
42 * present a tree block in the backref cache
43 */
44 struct backref_node {
45 struct rb_node rb_node;
46 u64 bytenr;
47
48 u64 new_bytenr;
49 /* objectid of tree block owner, can be not uptodate */
50 u64 owner;
51 /* link to pending, changed or detached list */
52 struct list_head list;
53 /* list of upper level blocks reference this block */
54 struct list_head upper;
55 /* list of child blocks in the cache */
56 struct list_head lower;
57 /* NULL if this node is not tree root */
58 struct btrfs_root *root;
59 /* extent buffer got by COW the block */
60 struct extent_buffer *eb;
61 /* level of tree block */
62 unsigned int level:8;
63 /* is the block in non-reference counted tree */
64 unsigned int cowonly:1;
65 /* 1 if no child node in the cache */
66 unsigned int lowest:1;
67 /* is the extent buffer locked */
68 unsigned int locked:1;
69 /* has the block been processed */
70 unsigned int processed:1;
71 /* have backrefs of this block been checked */
72 unsigned int checked:1;
73 /*
74 * 1 if corresponding block has been cowed but some upper
75 * level block pointers may not point to the new location
76 */
77 unsigned int pending:1;
78 /*
79 * 1 if the backref node isn't connected to any other
80 * backref node.
81 */
82 unsigned int detached:1;
83 };
84
85 /*
86 * present a block pointer in the backref cache
87 */
88 struct backref_edge {
89 struct list_head list[2];
90 struct backref_node *node[2];
91 };
92
93 #define LOWER 0
94 #define UPPER 1
95
96 struct backref_cache {
97 /* red black tree of all backref nodes in the cache */
98 struct rb_root rb_root;
99 /* for passing backref nodes to btrfs_reloc_cow_block */
100 struct backref_node *path[BTRFS_MAX_LEVEL];
101 /*
102 * list of blocks that have been cowed but some block
103 * pointers in upper level blocks may not reflect the
104 * new location
105 */
106 struct list_head pending[BTRFS_MAX_LEVEL];
107 /* list of backref nodes with no child node */
108 struct list_head leaves;
109 /* list of blocks that have been cowed in current transaction */
110 struct list_head changed;
111 /* list of detached backref node. */
112 struct list_head detached;
113
114 u64 last_trans;
115
116 int nr_nodes;
117 int nr_edges;
118 };
119
120 /*
121 * map address of tree root to tree
122 */
123 struct mapping_node {
124 struct rb_node rb_node;
125 u64 bytenr;
126 void *data;
127 };
128
129 struct mapping_tree {
130 struct rb_root rb_root;
131 spinlock_t lock;
132 };
133
134 /*
135 * present a tree block to process
136 */
137 struct tree_block {
138 struct rb_node rb_node;
139 u64 bytenr;
140 struct btrfs_key key;
141 unsigned int level:8;
142 unsigned int key_ready:1;
143 };
144
145 #define MAX_EXTENTS 128
146
147 struct file_extent_cluster {
148 u64 start;
149 u64 end;
150 u64 boundary[MAX_EXTENTS];
151 unsigned int nr;
152 };
153
154 struct reloc_control {
155 /* block group to relocate */
156 struct btrfs_block_group_cache *block_group;
157 /* extent tree */
158 struct btrfs_root *extent_root;
159 /* inode for moving data */
160 struct inode *data_inode;
161
162 struct btrfs_block_rsv *block_rsv;
163
164 struct backref_cache backref_cache;
165
166 struct file_extent_cluster cluster;
167 /* tree blocks have been processed */
168 struct extent_io_tree processed_blocks;
169 /* map start of tree root to corresponding reloc tree */
170 struct mapping_tree reloc_root_tree;
171 /* list of reloc trees */
172 struct list_head reloc_roots;
173 /* size of metadata reservation for merging reloc trees */
174 u64 merging_rsv_size;
175 /* size of relocated tree nodes */
176 u64 nodes_relocated;
177
178 u64 search_start;
179 u64 extents_found;
180
181 int block_rsv_retries;
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 root = find_tree_root(rc, eb, ref0);
788 if (!root->ref_cows)
789 cur->cowonly = 1;
790 if (key.objectid == key.offset) {
791 if (root && !should_ignore_root(root))
792 cur->root = root;
793 else
794 list_add(&cur->list, &useless);
795 break;
796 }
797 }
798 #else
799 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
800 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
801 #endif
802 if (key.objectid == key.offset) {
803 /*
804 * only root blocks of reloc trees use
805 * backref of this type.
806 */
807 root = find_reloc_root(rc, cur->bytenr);
808 BUG_ON(!root);
809 cur->root = root;
810 break;
811 }
812
813 edge = alloc_backref_edge(cache);
814 if (!edge) {
815 err = -ENOMEM;
816 goto out;
817 }
818 rb_node = tree_search(&cache->rb_root, key.offset);
819 if (!rb_node) {
820 upper = alloc_backref_node(cache);
821 if (!upper) {
822 free_backref_edge(cache, edge);
823 err = -ENOMEM;
824 goto out;
825 }
826 upper->bytenr = key.offset;
827 upper->level = cur->level + 1;
828 /*
829 * backrefs for the upper level block isn't
830 * cached, add the block to pending list
831 */
832 list_add_tail(&edge->list[UPPER], &list);
833 } else {
834 upper = rb_entry(rb_node, struct backref_node,
835 rb_node);
836 BUG_ON(!upper->checked);
837 INIT_LIST_HEAD(&edge->list[UPPER]);
838 }
839 list_add_tail(&edge->list[LOWER], &cur->upper);
840 edge->node[LOWER] = cur;
841 edge->node[UPPER] = upper;
842
843 goto next;
844 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
845 goto next;
846 }
847
848 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
849 root = read_fs_root(rc->extent_root->fs_info, key.offset);
850 if (IS_ERR(root)) {
851 err = PTR_ERR(root);
852 goto out;
853 }
854
855 if (!root->ref_cows)
856 cur->cowonly = 1;
857
858 if (btrfs_root_level(&root->root_item) == cur->level) {
859 /* tree root */
860 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
861 cur->bytenr);
862 if (should_ignore_root(root))
863 list_add(&cur->list, &useless);
864 else
865 cur->root = root;
866 break;
867 }
868
869 level = cur->level + 1;
870
871 /*
872 * searching the tree to find upper level blocks
873 * reference the block.
874 */
875 path2->search_commit_root = 1;
876 path2->skip_locking = 1;
877 path2->lowest_level = level;
878 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
879 path2->lowest_level = 0;
880 if (ret < 0) {
881 err = ret;
882 goto out;
883 }
884 if (ret > 0 && path2->slots[level] > 0)
885 path2->slots[level]--;
886
887 eb = path2->nodes[level];
888 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
889 cur->bytenr);
890
891 lower = cur;
892 for (; level < BTRFS_MAX_LEVEL; level++) {
893 if (!path2->nodes[level]) {
894 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
895 lower->bytenr);
896 if (should_ignore_root(root))
897 list_add(&lower->list, &useless);
898 else
899 lower->root = root;
900 break;
901 }
902
903 edge = alloc_backref_edge(cache);
904 if (!edge) {
905 err = -ENOMEM;
906 goto out;
907 }
908
909 eb = path2->nodes[level];
910 rb_node = tree_search(&cache->rb_root, eb->start);
911 if (!rb_node) {
912 upper = alloc_backref_node(cache);
913 if (!upper) {
914 free_backref_edge(cache, edge);
915 err = -ENOMEM;
916 goto out;
917 }
918 upper->bytenr = eb->start;
919 upper->owner = btrfs_header_owner(eb);
920 upper->level = lower->level + 1;
921 if (!root->ref_cows)
922 upper->cowonly = 1;
923
924 /*
925 * if we know the block isn't shared
926 * we can void checking its backrefs.
927 */
928 if (btrfs_block_can_be_shared(root, eb))
929 upper->checked = 0;
930 else
931 upper->checked = 1;
932
933 /*
934 * add the block to pending list if we
935 * need check its backrefs. only block
936 * at 'cur->level + 1' is added to the
937 * tail of pending list. this guarantees
938 * we check backrefs from lower level
939 * blocks to upper level blocks.
940 */
941 if (!upper->checked &&
942 level == cur->level + 1) {
943 list_add_tail(&edge->list[UPPER],
944 &list);
945 } else
946 INIT_LIST_HEAD(&edge->list[UPPER]);
947 } else {
948 upper = rb_entry(rb_node, struct backref_node,
949 rb_node);
950 BUG_ON(!upper->checked);
951 INIT_LIST_HEAD(&edge->list[UPPER]);
952 if (!upper->owner)
953 upper->owner = btrfs_header_owner(eb);
954 }
955 list_add_tail(&edge->list[LOWER], &lower->upper);
956 edge->node[LOWER] = lower;
957 edge->node[UPPER] = upper;
958
959 if (rb_node)
960 break;
961 lower = upper;
962 upper = NULL;
963 }
964 btrfs_release_path(root, path2);
965 next:
966 if (ptr < end) {
967 ptr += btrfs_extent_inline_ref_size(key.type);
968 if (ptr >= end) {
969 WARN_ON(ptr > end);
970 ptr = 0;
971 end = 0;
972 }
973 }
974 if (ptr >= end)
975 path1->slots[0]++;
976 }
977 btrfs_release_path(rc->extent_root, path1);
978
979 cur->checked = 1;
980 WARN_ON(exist);
981
982 /* the pending list isn't empty, take the first block to process */
983 if (!list_empty(&list)) {
984 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
985 list_del_init(&edge->list[UPPER]);
986 cur = edge->node[UPPER];
987 goto again;
988 }
989
990 /*
991 * everything goes well, connect backref nodes and insert backref nodes
992 * into the cache.
993 */
994 BUG_ON(!node->checked);
995 cowonly = node->cowonly;
996 if (!cowonly) {
997 rb_node = tree_insert(&cache->rb_root, node->bytenr,
998 &node->rb_node);
999 BUG_ON(rb_node);
1000 list_add_tail(&node->lower, &cache->leaves);
1001 }
1002
1003 list_for_each_entry(edge, &node->upper, list[LOWER])
1004 list_add_tail(&edge->list[UPPER], &list);
1005
1006 while (!list_empty(&list)) {
1007 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1008 list_del_init(&edge->list[UPPER]);
1009 upper = edge->node[UPPER];
1010 if (upper->detached) {
1011 list_del(&edge->list[LOWER]);
1012 lower = edge->node[LOWER];
1013 free_backref_edge(cache, edge);
1014 if (list_empty(&lower->upper))
1015 list_add(&lower->list, &useless);
1016 continue;
1017 }
1018
1019 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1020 if (upper->lowest) {
1021 list_del_init(&upper->lower);
1022 upper->lowest = 0;
1023 }
1024
1025 list_add_tail(&edge->list[UPPER], &upper->lower);
1026 continue;
1027 }
1028
1029 BUG_ON(!upper->checked);
1030 BUG_ON(cowonly != upper->cowonly);
1031 if (!cowonly) {
1032 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1033 &upper->rb_node);
1034 BUG_ON(rb_node);
1035 }
1036
1037 list_add_tail(&edge->list[UPPER], &upper->lower);
1038
1039 list_for_each_entry(edge, &upper->upper, list[LOWER])
1040 list_add_tail(&edge->list[UPPER], &list);
1041 }
1042 /*
1043 * process useless backref nodes. backref nodes for tree leaves
1044 * are deleted from the cache. backref nodes for upper level
1045 * tree blocks are left in the cache to avoid unnecessary backref
1046 * lookup.
1047 */
1048 while (!list_empty(&useless)) {
1049 upper = list_entry(useless.next, struct backref_node, list);
1050 list_del_init(&upper->list);
1051 BUG_ON(!list_empty(&upper->upper));
1052 if (upper == node)
1053 node = NULL;
1054 if (upper->lowest) {
1055 list_del_init(&upper->lower);
1056 upper->lowest = 0;
1057 }
1058 while (!list_empty(&upper->lower)) {
1059 edge = list_entry(upper->lower.next,
1060 struct backref_edge, list[UPPER]);
1061 list_del(&edge->list[UPPER]);
1062 list_del(&edge->list[LOWER]);
1063 lower = edge->node[LOWER];
1064 free_backref_edge(cache, edge);
1065
1066 if (list_empty(&lower->upper))
1067 list_add(&lower->list, &useless);
1068 }
1069 __mark_block_processed(rc, upper);
1070 if (upper->level > 0) {
1071 list_add(&upper->list, &cache->detached);
1072 upper->detached = 1;
1073 } else {
1074 rb_erase(&upper->rb_node, &cache->rb_root);
1075 free_backref_node(cache, upper);
1076 }
1077 }
1078 out:
1079 btrfs_free_path(path1);
1080 btrfs_free_path(path2);
1081 if (err) {
1082 while (!list_empty(&useless)) {
1083 lower = list_entry(useless.next,
1084 struct backref_node, upper);
1085 list_del_init(&lower->upper);
1086 }
1087 upper = node;
1088 INIT_LIST_HEAD(&list);
1089 while (upper) {
1090 if (RB_EMPTY_NODE(&upper->rb_node)) {
1091 list_splice_tail(&upper->upper, &list);
1092 free_backref_node(cache, upper);
1093 }
1094
1095 if (list_empty(&list))
1096 break;
1097
1098 edge = list_entry(list.next, struct backref_edge,
1099 list[LOWER]);
1100 list_del(&edge->list[LOWER]);
1101 upper = edge->node[UPPER];
1102 free_backref_edge(cache, edge);
1103 }
1104 return ERR_PTR(err);
1105 }
1106 BUG_ON(node && node->detached);
1107 return node;
1108 }
1109
1110 /*
1111 * helper to add backref node for the newly created snapshot.
1112 * the backref node is created by cloning backref node that
1113 * corresponds to root of source tree
1114 */
1115 static int clone_backref_node(struct btrfs_trans_handle *trans,
1116 struct reloc_control *rc,
1117 struct btrfs_root *src,
1118 struct btrfs_root *dest)
1119 {
1120 struct btrfs_root *reloc_root = src->reloc_root;
1121 struct backref_cache *cache = &rc->backref_cache;
1122 struct backref_node *node = NULL;
1123 struct backref_node *new_node;
1124 struct backref_edge *edge;
1125 struct backref_edge *new_edge;
1126 struct rb_node *rb_node;
1127
1128 if (cache->last_trans > 0)
1129 update_backref_cache(trans, cache);
1130
1131 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1132 if (rb_node) {
1133 node = rb_entry(rb_node, struct backref_node, rb_node);
1134 if (node->detached)
1135 node = NULL;
1136 else
1137 BUG_ON(node->new_bytenr != reloc_root->node->start);
1138 }
1139
1140 if (!node) {
1141 rb_node = tree_search(&cache->rb_root,
1142 reloc_root->commit_root->start);
1143 if (rb_node) {
1144 node = rb_entry(rb_node, struct backref_node,
1145 rb_node);
1146 BUG_ON(node->detached);
1147 }
1148 }
1149
1150 if (!node)
1151 return 0;
1152
1153 new_node = alloc_backref_node(cache);
1154 if (!new_node)
1155 return -ENOMEM;
1156
1157 new_node->bytenr = dest->node->start;
1158 new_node->level = node->level;
1159 new_node->lowest = node->lowest;
1160 new_node->root = dest;
1161
1162 if (!node->lowest) {
1163 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1164 new_edge = alloc_backref_edge(cache);
1165 if (!new_edge)
1166 goto fail;
1167
1168 new_edge->node[UPPER] = new_node;
1169 new_edge->node[LOWER] = edge->node[LOWER];
1170 list_add_tail(&new_edge->list[UPPER],
1171 &new_node->lower);
1172 }
1173 }
1174
1175 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1176 &new_node->rb_node);
1177 BUG_ON(rb_node);
1178
1179 if (!new_node->lowest) {
1180 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1181 list_add_tail(&new_edge->list[LOWER],
1182 &new_edge->node[LOWER]->upper);
1183 }
1184 }
1185 return 0;
1186 fail:
1187 while (!list_empty(&new_node->lower)) {
1188 new_edge = list_entry(new_node->lower.next,
1189 struct backref_edge, list[UPPER]);
1190 list_del(&new_edge->list[UPPER]);
1191 free_backref_edge(cache, new_edge);
1192 }
1193 free_backref_node(cache, new_node);
1194 return -ENOMEM;
1195 }
1196
1197 /*
1198 * helper to add 'address of tree root -> reloc tree' mapping
1199 */
1200 static int __add_reloc_root(struct btrfs_root *root)
1201 {
1202 struct rb_node *rb_node;
1203 struct mapping_node *node;
1204 struct reloc_control *rc = root->fs_info->reloc_ctl;
1205
1206 node = kmalloc(sizeof(*node), GFP_NOFS);
1207 BUG_ON(!node);
1208
1209 node->bytenr = root->node->start;
1210 node->data = root;
1211
1212 spin_lock(&rc->reloc_root_tree.lock);
1213 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1214 node->bytenr, &node->rb_node);
1215 spin_unlock(&rc->reloc_root_tree.lock);
1216 BUG_ON(rb_node);
1217
1218 list_add_tail(&root->root_list, &rc->reloc_roots);
1219 return 0;
1220 }
1221
1222 /*
1223 * helper to update/delete the 'address of tree root -> reloc tree'
1224 * mapping
1225 */
1226 static int __update_reloc_root(struct btrfs_root *root, int del)
1227 {
1228 struct rb_node *rb_node;
1229 struct mapping_node *node = NULL;
1230 struct reloc_control *rc = root->fs_info->reloc_ctl;
1231
1232 spin_lock(&rc->reloc_root_tree.lock);
1233 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1234 root->commit_root->start);
1235 if (rb_node) {
1236 node = rb_entry(rb_node, struct mapping_node, rb_node);
1237 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1238 }
1239 spin_unlock(&rc->reloc_root_tree.lock);
1240
1241 BUG_ON((struct btrfs_root *)node->data != root);
1242
1243 if (!del) {
1244 spin_lock(&rc->reloc_root_tree.lock);
1245 node->bytenr = root->node->start;
1246 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1247 node->bytenr, &node->rb_node);
1248 spin_unlock(&rc->reloc_root_tree.lock);
1249 BUG_ON(rb_node);
1250 } else {
1251 list_del_init(&root->root_list);
1252 kfree(node);
1253 }
1254 return 0;
1255 }
1256
1257 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1258 struct btrfs_root *root, u64 objectid)
1259 {
1260 struct btrfs_root *reloc_root;
1261 struct extent_buffer *eb;
1262 struct btrfs_root_item *root_item;
1263 struct btrfs_key root_key;
1264 int ret;
1265
1266 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1267 BUG_ON(!root_item);
1268
1269 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1270 root_key.type = BTRFS_ROOT_ITEM_KEY;
1271 root_key.offset = objectid;
1272
1273 if (root->root_key.objectid == objectid) {
1274 /* called by btrfs_init_reloc_root */
1275 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1276 BTRFS_TREE_RELOC_OBJECTID);
1277 BUG_ON(ret);
1278
1279 btrfs_set_root_last_snapshot(&root->root_item,
1280 trans->transid - 1);
1281 } else {
1282 /*
1283 * called by btrfs_reloc_post_snapshot_hook.
1284 * the source tree is a reloc tree, all tree blocks
1285 * modified after it was created have RELOC flag
1286 * set in their headers. so it's OK to not update
1287 * the 'last_snapshot'.
1288 */
1289 ret = btrfs_copy_root(trans, root, root->node, &eb,
1290 BTRFS_TREE_RELOC_OBJECTID);
1291 BUG_ON(ret);
1292 }
1293
1294 memcpy(root_item, &root->root_item, sizeof(*root_item));
1295 btrfs_set_root_bytenr(root_item, eb->start);
1296 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1297 btrfs_set_root_generation(root_item, trans->transid);
1298
1299 if (root->root_key.objectid == objectid) {
1300 btrfs_set_root_refs(root_item, 0);
1301 memset(&root_item->drop_progress, 0,
1302 sizeof(struct btrfs_disk_key));
1303 root_item->drop_level = 0;
1304 }
1305
1306 btrfs_tree_unlock(eb);
1307 free_extent_buffer(eb);
1308
1309 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1310 &root_key, root_item);
1311 BUG_ON(ret);
1312 kfree(root_item);
1313
1314 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
1315 &root_key);
1316 BUG_ON(IS_ERR(reloc_root));
1317 reloc_root->last_trans = trans->transid;
1318 return reloc_root;
1319 }
1320
1321 /*
1322 * create reloc tree for a given fs tree. reloc tree is just a
1323 * snapshot of the fs tree with special root objectid.
1324 */
1325 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1326 struct btrfs_root *root)
1327 {
1328 struct btrfs_root *reloc_root;
1329 struct reloc_control *rc = root->fs_info->reloc_ctl;
1330 int clear_rsv = 0;
1331
1332 if (root->reloc_root) {
1333 reloc_root = root->reloc_root;
1334 reloc_root->last_trans = trans->transid;
1335 return 0;
1336 }
1337
1338 if (!rc || !rc->create_reloc_tree ||
1339 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1340 return 0;
1341
1342 if (!trans->block_rsv) {
1343 trans->block_rsv = rc->block_rsv;
1344 clear_rsv = 1;
1345 }
1346 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1347 if (clear_rsv)
1348 trans->block_rsv = NULL;
1349
1350 __add_reloc_root(reloc_root);
1351 root->reloc_root = reloc_root;
1352 return 0;
1353 }
1354
1355 /*
1356 * update root item of reloc tree
1357 */
1358 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1359 struct btrfs_root *root)
1360 {
1361 struct btrfs_root *reloc_root;
1362 struct btrfs_root_item *root_item;
1363 int del = 0;
1364 int ret;
1365
1366 if (!root->reloc_root)
1367 return 0;
1368
1369 reloc_root = root->reloc_root;
1370 root_item = &reloc_root->root_item;
1371
1372 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1373 btrfs_root_refs(root_item) == 0) {
1374 root->reloc_root = NULL;
1375 del = 1;
1376 }
1377
1378 __update_reloc_root(reloc_root, del);
1379
1380 if (reloc_root->commit_root != reloc_root->node) {
1381 btrfs_set_root_node(root_item, reloc_root->node);
1382 free_extent_buffer(reloc_root->commit_root);
1383 reloc_root->commit_root = btrfs_root_node(reloc_root);
1384 }
1385
1386 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1387 &reloc_root->root_key, root_item);
1388 BUG_ON(ret);
1389 return 0;
1390 }
1391
1392 /*
1393 * helper to find first cached inode with inode number >= objectid
1394 * in a subvolume
1395 */
1396 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1397 {
1398 struct rb_node *node;
1399 struct rb_node *prev;
1400 struct btrfs_inode *entry;
1401 struct inode *inode;
1402
1403 spin_lock(&root->inode_lock);
1404 again:
1405 node = root->inode_tree.rb_node;
1406 prev = NULL;
1407 while (node) {
1408 prev = node;
1409 entry = rb_entry(node, struct btrfs_inode, rb_node);
1410
1411 if (objectid < entry->vfs_inode.i_ino)
1412 node = node->rb_left;
1413 else if (objectid > entry->vfs_inode.i_ino)
1414 node = node->rb_right;
1415 else
1416 break;
1417 }
1418 if (!node) {
1419 while (prev) {
1420 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1421 if (objectid <= entry->vfs_inode.i_ino) {
1422 node = prev;
1423 break;
1424 }
1425 prev = rb_next(prev);
1426 }
1427 }
1428 while (node) {
1429 entry = rb_entry(node, struct btrfs_inode, rb_node);
1430 inode = igrab(&entry->vfs_inode);
1431 if (inode) {
1432 spin_unlock(&root->inode_lock);
1433 return inode;
1434 }
1435
1436 objectid = entry->vfs_inode.i_ino + 1;
1437 if (cond_resched_lock(&root->inode_lock))
1438 goto again;
1439
1440 node = rb_next(node);
1441 }
1442 spin_unlock(&root->inode_lock);
1443 return NULL;
1444 }
1445
1446 static int in_block_group(u64 bytenr,
1447 struct btrfs_block_group_cache *block_group)
1448 {
1449 if (bytenr >= block_group->key.objectid &&
1450 bytenr < block_group->key.objectid + block_group->key.offset)
1451 return 1;
1452 return 0;
1453 }
1454
1455 /*
1456 * get new location of data
1457 */
1458 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1459 u64 bytenr, u64 num_bytes)
1460 {
1461 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1462 struct btrfs_path *path;
1463 struct btrfs_file_extent_item *fi;
1464 struct extent_buffer *leaf;
1465 int ret;
1466
1467 path = btrfs_alloc_path();
1468 if (!path)
1469 return -ENOMEM;
1470
1471 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1472 ret = btrfs_lookup_file_extent(NULL, root, path, reloc_inode->i_ino,
1473 bytenr, 0);
1474 if (ret < 0)
1475 goto out;
1476 if (ret > 0) {
1477 ret = -ENOENT;
1478 goto out;
1479 }
1480
1481 leaf = path->nodes[0];
1482 fi = btrfs_item_ptr(leaf, path->slots[0],
1483 struct btrfs_file_extent_item);
1484
1485 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1486 btrfs_file_extent_compression(leaf, fi) ||
1487 btrfs_file_extent_encryption(leaf, fi) ||
1488 btrfs_file_extent_other_encoding(leaf, fi));
1489
1490 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1491 ret = 1;
1492 goto out;
1493 }
1494
1495 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1496 ret = 0;
1497 out:
1498 btrfs_free_path(path);
1499 return ret;
1500 }
1501
1502 /*
1503 * update file extent items in the tree leaf to point to
1504 * the new locations.
1505 */
1506 static noinline_for_stack
1507 int replace_file_extents(struct btrfs_trans_handle *trans,
1508 struct reloc_control *rc,
1509 struct btrfs_root *root,
1510 struct extent_buffer *leaf)
1511 {
1512 struct btrfs_key key;
1513 struct btrfs_file_extent_item *fi;
1514 struct inode *inode = NULL;
1515 u64 parent;
1516 u64 bytenr;
1517 u64 new_bytenr = 0;
1518 u64 num_bytes;
1519 u64 end;
1520 u32 nritems;
1521 u32 i;
1522 int ret;
1523 int first = 1;
1524 int dirty = 0;
1525
1526 if (rc->stage != UPDATE_DATA_PTRS)
1527 return 0;
1528
1529 /* reloc trees always use full backref */
1530 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1531 parent = leaf->start;
1532 else
1533 parent = 0;
1534
1535 nritems = btrfs_header_nritems(leaf);
1536 for (i = 0; i < nritems; i++) {
1537 cond_resched();
1538 btrfs_item_key_to_cpu(leaf, &key, i);
1539 if (key.type != BTRFS_EXTENT_DATA_KEY)
1540 continue;
1541 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1542 if (btrfs_file_extent_type(leaf, fi) ==
1543 BTRFS_FILE_EXTENT_INLINE)
1544 continue;
1545 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1546 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1547 if (bytenr == 0)
1548 continue;
1549 if (!in_block_group(bytenr, rc->block_group))
1550 continue;
1551
1552 /*
1553 * if we are modifying block in fs tree, wait for readpage
1554 * to complete and drop the extent cache
1555 */
1556 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1557 if (first) {
1558 inode = find_next_inode(root, key.objectid);
1559 first = 0;
1560 } else if (inode && inode->i_ino < key.objectid) {
1561 btrfs_add_delayed_iput(inode);
1562 inode = find_next_inode(root, key.objectid);
1563 }
1564 if (inode && inode->i_ino == key.objectid) {
1565 end = key.offset +
1566 btrfs_file_extent_num_bytes(leaf, fi);
1567 WARN_ON(!IS_ALIGNED(key.offset,
1568 root->sectorsize));
1569 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1570 end--;
1571 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1572 key.offset, end,
1573 GFP_NOFS);
1574 if (!ret)
1575 continue;
1576
1577 btrfs_drop_extent_cache(inode, key.offset, end,
1578 1);
1579 unlock_extent(&BTRFS_I(inode)->io_tree,
1580 key.offset, end, GFP_NOFS);
1581 }
1582 }
1583
1584 ret = get_new_location(rc->data_inode, &new_bytenr,
1585 bytenr, num_bytes);
1586 if (ret > 0) {
1587 WARN_ON(1);
1588 continue;
1589 }
1590 BUG_ON(ret < 0);
1591
1592 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1593 dirty = 1;
1594
1595 key.offset -= btrfs_file_extent_offset(leaf, fi);
1596 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1597 num_bytes, parent,
1598 btrfs_header_owner(leaf),
1599 key.objectid, key.offset);
1600 BUG_ON(ret);
1601
1602 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1603 parent, btrfs_header_owner(leaf),
1604 key.objectid, key.offset);
1605 BUG_ON(ret);
1606 }
1607 if (dirty)
1608 btrfs_mark_buffer_dirty(leaf);
1609 if (inode)
1610 btrfs_add_delayed_iput(inode);
1611 return 0;
1612 }
1613
1614 static noinline_for_stack
1615 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1616 struct btrfs_path *path, int level)
1617 {
1618 struct btrfs_disk_key key1;
1619 struct btrfs_disk_key key2;
1620 btrfs_node_key(eb, &key1, slot);
1621 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1622 return memcmp(&key1, &key2, sizeof(key1));
1623 }
1624
1625 /*
1626 * try to replace tree blocks in fs tree with the new blocks
1627 * in reloc tree. tree blocks haven't been modified since the
1628 * reloc tree was create can be replaced.
1629 *
1630 * if a block was replaced, level of the block + 1 is returned.
1631 * if no block got replaced, 0 is returned. if there are other
1632 * errors, a negative error number is returned.
1633 */
1634 static noinline_for_stack
1635 int replace_path(struct btrfs_trans_handle *trans,
1636 struct btrfs_root *dest, struct btrfs_root *src,
1637 struct btrfs_path *path, struct btrfs_key *next_key,
1638 int lowest_level, int max_level)
1639 {
1640 struct extent_buffer *eb;
1641 struct extent_buffer *parent;
1642 struct btrfs_key key;
1643 u64 old_bytenr;
1644 u64 new_bytenr;
1645 u64 old_ptr_gen;
1646 u64 new_ptr_gen;
1647 u64 last_snapshot;
1648 u32 blocksize;
1649 int cow = 0;
1650 int level;
1651 int ret;
1652 int slot;
1653
1654 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1655 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1656
1657 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1658 again:
1659 slot = path->slots[lowest_level];
1660 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1661
1662 eb = btrfs_lock_root_node(dest);
1663 btrfs_set_lock_blocking(eb);
1664 level = btrfs_header_level(eb);
1665
1666 if (level < lowest_level) {
1667 btrfs_tree_unlock(eb);
1668 free_extent_buffer(eb);
1669 return 0;
1670 }
1671
1672 if (cow) {
1673 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1674 BUG_ON(ret);
1675 }
1676 btrfs_set_lock_blocking(eb);
1677
1678 if (next_key) {
1679 next_key->objectid = (u64)-1;
1680 next_key->type = (u8)-1;
1681 next_key->offset = (u64)-1;
1682 }
1683
1684 parent = eb;
1685 while (1) {
1686 level = btrfs_header_level(parent);
1687 BUG_ON(level < lowest_level);
1688
1689 ret = btrfs_bin_search(parent, &key, level, &slot);
1690 if (ret && slot > 0)
1691 slot--;
1692
1693 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1694 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1695
1696 old_bytenr = btrfs_node_blockptr(parent, slot);
1697 blocksize = btrfs_level_size(dest, level - 1);
1698 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1699
1700 if (level <= max_level) {
1701 eb = path->nodes[level];
1702 new_bytenr = btrfs_node_blockptr(eb,
1703 path->slots[level]);
1704 new_ptr_gen = btrfs_node_ptr_generation(eb,
1705 path->slots[level]);
1706 } else {
1707 new_bytenr = 0;
1708 new_ptr_gen = 0;
1709 }
1710
1711 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1712 WARN_ON(1);
1713 ret = level;
1714 break;
1715 }
1716
1717 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1718 memcmp_node_keys(parent, slot, path, level)) {
1719 if (level <= lowest_level) {
1720 ret = 0;
1721 break;
1722 }
1723
1724 eb = read_tree_block(dest, old_bytenr, blocksize,
1725 old_ptr_gen);
1726 btrfs_tree_lock(eb);
1727 if (cow) {
1728 ret = btrfs_cow_block(trans, dest, eb, parent,
1729 slot, &eb);
1730 BUG_ON(ret);
1731 }
1732 btrfs_set_lock_blocking(eb);
1733
1734 btrfs_tree_unlock(parent);
1735 free_extent_buffer(parent);
1736
1737 parent = eb;
1738 continue;
1739 }
1740
1741 if (!cow) {
1742 btrfs_tree_unlock(parent);
1743 free_extent_buffer(parent);
1744 cow = 1;
1745 goto again;
1746 }
1747
1748 btrfs_node_key_to_cpu(path->nodes[level], &key,
1749 path->slots[level]);
1750 btrfs_release_path(src, path);
1751
1752 path->lowest_level = level;
1753 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1754 path->lowest_level = 0;
1755 BUG_ON(ret);
1756
1757 /*
1758 * swap blocks in fs tree and reloc tree.
1759 */
1760 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1761 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1762 btrfs_mark_buffer_dirty(parent);
1763
1764 btrfs_set_node_blockptr(path->nodes[level],
1765 path->slots[level], old_bytenr);
1766 btrfs_set_node_ptr_generation(path->nodes[level],
1767 path->slots[level], old_ptr_gen);
1768 btrfs_mark_buffer_dirty(path->nodes[level]);
1769
1770 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1771 path->nodes[level]->start,
1772 src->root_key.objectid, level - 1, 0);
1773 BUG_ON(ret);
1774 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1775 0, dest->root_key.objectid, level - 1,
1776 0);
1777 BUG_ON(ret);
1778
1779 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1780 path->nodes[level]->start,
1781 src->root_key.objectid, level - 1, 0);
1782 BUG_ON(ret);
1783
1784 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1785 0, dest->root_key.objectid, level - 1,
1786 0);
1787 BUG_ON(ret);
1788
1789 btrfs_unlock_up_safe(path, 0);
1790
1791 ret = level;
1792 break;
1793 }
1794 btrfs_tree_unlock(parent);
1795 free_extent_buffer(parent);
1796 return ret;
1797 }
1798
1799 /*
1800 * helper to find next relocated block in reloc tree
1801 */
1802 static noinline_for_stack
1803 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1804 int *level)
1805 {
1806 struct extent_buffer *eb;
1807 int i;
1808 u64 last_snapshot;
1809 u32 nritems;
1810
1811 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1812
1813 for (i = 0; i < *level; i++) {
1814 free_extent_buffer(path->nodes[i]);
1815 path->nodes[i] = NULL;
1816 }
1817
1818 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1819 eb = path->nodes[i];
1820 nritems = btrfs_header_nritems(eb);
1821 while (path->slots[i] + 1 < nritems) {
1822 path->slots[i]++;
1823 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1824 last_snapshot)
1825 continue;
1826
1827 *level = i;
1828 return 0;
1829 }
1830 free_extent_buffer(path->nodes[i]);
1831 path->nodes[i] = NULL;
1832 }
1833 return 1;
1834 }
1835
1836 /*
1837 * walk down reloc tree to find relocated block of lowest level
1838 */
1839 static noinline_for_stack
1840 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1841 int *level)
1842 {
1843 struct extent_buffer *eb = NULL;
1844 int i;
1845 u64 bytenr;
1846 u64 ptr_gen = 0;
1847 u64 last_snapshot;
1848 u32 blocksize;
1849 u32 nritems;
1850
1851 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1852
1853 for (i = *level; i > 0; i--) {
1854 eb = path->nodes[i];
1855 nritems = btrfs_header_nritems(eb);
1856 while (path->slots[i] < nritems) {
1857 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1858 if (ptr_gen > last_snapshot)
1859 break;
1860 path->slots[i]++;
1861 }
1862 if (path->slots[i] >= nritems) {
1863 if (i == *level)
1864 break;
1865 *level = i + 1;
1866 return 0;
1867 }
1868 if (i == 1) {
1869 *level = i;
1870 return 0;
1871 }
1872
1873 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1874 blocksize = btrfs_level_size(root, i - 1);
1875 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1876 BUG_ON(btrfs_header_level(eb) != i - 1);
1877 path->nodes[i - 1] = eb;
1878 path->slots[i - 1] = 0;
1879 }
1880 return 1;
1881 }
1882
1883 /*
1884 * invalidate extent cache for file extents whose key in range of
1885 * [min_key, max_key)
1886 */
1887 static int invalidate_extent_cache(struct btrfs_root *root,
1888 struct btrfs_key *min_key,
1889 struct btrfs_key *max_key)
1890 {
1891 struct inode *inode = NULL;
1892 u64 objectid;
1893 u64 start, end;
1894
1895 objectid = min_key->objectid;
1896 while (1) {
1897 cond_resched();
1898 iput(inode);
1899
1900 if (objectid > max_key->objectid)
1901 break;
1902
1903 inode = find_next_inode(root, objectid);
1904 if (!inode)
1905 break;
1906
1907 if (inode->i_ino > max_key->objectid) {
1908 iput(inode);
1909 break;
1910 }
1911
1912 objectid = inode->i_ino + 1;
1913 if (!S_ISREG(inode->i_mode))
1914 continue;
1915
1916 if (unlikely(min_key->objectid == inode->i_ino)) {
1917 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1918 continue;
1919 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1920 start = 0;
1921 else {
1922 start = min_key->offset;
1923 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1924 }
1925 } else {
1926 start = 0;
1927 }
1928
1929 if (unlikely(max_key->objectid == inode->i_ino)) {
1930 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1931 continue;
1932 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1933 end = (u64)-1;
1934 } else {
1935 if (max_key->offset == 0)
1936 continue;
1937 end = max_key->offset;
1938 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1939 end--;
1940 }
1941 } else {
1942 end = (u64)-1;
1943 }
1944
1945 /* the lock_extent waits for readpage to complete */
1946 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1947 btrfs_drop_extent_cache(inode, start, end, 1);
1948 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1949 }
1950 return 0;
1951 }
1952
1953 static int find_next_key(struct btrfs_path *path, int level,
1954 struct btrfs_key *key)
1955
1956 {
1957 while (level < BTRFS_MAX_LEVEL) {
1958 if (!path->nodes[level])
1959 break;
1960 if (path->slots[level] + 1 <
1961 btrfs_header_nritems(path->nodes[level])) {
1962 btrfs_node_key_to_cpu(path->nodes[level], key,
1963 path->slots[level] + 1);
1964 return 0;
1965 }
1966 level++;
1967 }
1968 return 1;
1969 }
1970
1971 /*
1972 * merge the relocated tree blocks in reloc tree with corresponding
1973 * fs tree.
1974 */
1975 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1976 struct btrfs_root *root)
1977 {
1978 LIST_HEAD(inode_list);
1979 struct btrfs_key key;
1980 struct btrfs_key next_key;
1981 struct btrfs_trans_handle *trans;
1982 struct btrfs_root *reloc_root;
1983 struct btrfs_root_item *root_item;
1984 struct btrfs_path *path;
1985 struct extent_buffer *leaf;
1986 unsigned long nr;
1987 int level;
1988 int max_level;
1989 int replaced = 0;
1990 int ret;
1991 int err = 0;
1992 u32 min_reserved;
1993
1994 path = btrfs_alloc_path();
1995 if (!path)
1996 return -ENOMEM;
1997
1998 reloc_root = root->reloc_root;
1999 root_item = &reloc_root->root_item;
2000
2001 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2002 level = btrfs_root_level(root_item);
2003 extent_buffer_get(reloc_root->node);
2004 path->nodes[level] = reloc_root->node;
2005 path->slots[level] = 0;
2006 } else {
2007 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2008
2009 level = root_item->drop_level;
2010 BUG_ON(level == 0);
2011 path->lowest_level = level;
2012 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2013 path->lowest_level = 0;
2014 if (ret < 0) {
2015 btrfs_free_path(path);
2016 return ret;
2017 }
2018
2019 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2020 path->slots[level]);
2021 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2022
2023 btrfs_unlock_up_safe(path, 0);
2024 }
2025
2026 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2027 memset(&next_key, 0, sizeof(next_key));
2028
2029 while (1) {
2030 trans = btrfs_start_transaction(root, 0);
2031 trans->block_rsv = rc->block_rsv;
2032
2033 ret = btrfs_block_rsv_check(trans, root, rc->block_rsv,
2034 min_reserved, 0);
2035 if (ret) {
2036 BUG_ON(ret != -EAGAIN);
2037 ret = btrfs_commit_transaction(trans, root);
2038 BUG_ON(ret);
2039 continue;
2040 }
2041
2042 replaced = 0;
2043 max_level = level;
2044
2045 ret = walk_down_reloc_tree(reloc_root, path, &level);
2046 if (ret < 0) {
2047 err = ret;
2048 goto out;
2049 }
2050 if (ret > 0)
2051 break;
2052
2053 if (!find_next_key(path, level, &key) &&
2054 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2055 ret = 0;
2056 } else {
2057 ret = replace_path(trans, root, reloc_root, path,
2058 &next_key, level, max_level);
2059 }
2060 if (ret < 0) {
2061 err = ret;
2062 goto out;
2063 }
2064
2065 if (ret > 0) {
2066 level = ret;
2067 btrfs_node_key_to_cpu(path->nodes[level], &key,
2068 path->slots[level]);
2069 replaced = 1;
2070 }
2071
2072 ret = walk_up_reloc_tree(reloc_root, path, &level);
2073 if (ret > 0)
2074 break;
2075
2076 BUG_ON(level == 0);
2077 /*
2078 * save the merging progress in the drop_progress.
2079 * this is OK since root refs == 1 in this case.
2080 */
2081 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2082 path->slots[level]);
2083 root_item->drop_level = level;
2084
2085 nr = trans->blocks_used;
2086 btrfs_end_transaction_throttle(trans, root);
2087
2088 btrfs_btree_balance_dirty(root, nr);
2089
2090 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2091 invalidate_extent_cache(root, &key, &next_key);
2092 }
2093
2094 /*
2095 * handle the case only one block in the fs tree need to be
2096 * relocated and the block is tree root.
2097 */
2098 leaf = btrfs_lock_root_node(root);
2099 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2100 btrfs_tree_unlock(leaf);
2101 free_extent_buffer(leaf);
2102 if (ret < 0)
2103 err = ret;
2104 out:
2105 btrfs_free_path(path);
2106
2107 if (err == 0) {
2108 memset(&root_item->drop_progress, 0,
2109 sizeof(root_item->drop_progress));
2110 root_item->drop_level = 0;
2111 btrfs_set_root_refs(root_item, 0);
2112 btrfs_update_reloc_root(trans, root);
2113 }
2114
2115 nr = trans->blocks_used;
2116 btrfs_end_transaction_throttle(trans, root);
2117
2118 btrfs_btree_balance_dirty(root, nr);
2119
2120 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2121 invalidate_extent_cache(root, &key, &next_key);
2122
2123 return err;
2124 }
2125
2126 static noinline_for_stack
2127 int prepare_to_merge(struct reloc_control *rc, int err)
2128 {
2129 struct btrfs_root *root = rc->extent_root;
2130 struct btrfs_root *reloc_root;
2131 struct btrfs_trans_handle *trans;
2132 LIST_HEAD(reloc_roots);
2133 u64 num_bytes = 0;
2134 int ret;
2135 int retries = 0;
2136
2137 mutex_lock(&root->fs_info->trans_mutex);
2138 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2139 rc->merging_rsv_size += rc->nodes_relocated * 2;
2140 mutex_unlock(&root->fs_info->trans_mutex);
2141 again:
2142 if (!err) {
2143 num_bytes = rc->merging_rsv_size;
2144 ret = btrfs_block_rsv_add(NULL, root, rc->block_rsv,
2145 num_bytes, &retries);
2146 if (ret)
2147 err = ret;
2148 }
2149
2150 trans = btrfs_join_transaction(rc->extent_root, 1);
2151
2152 if (!err) {
2153 if (num_bytes != rc->merging_rsv_size) {
2154 btrfs_end_transaction(trans, rc->extent_root);
2155 btrfs_block_rsv_release(rc->extent_root,
2156 rc->block_rsv, num_bytes);
2157 retries = 0;
2158 goto again;
2159 }
2160 }
2161
2162 rc->merge_reloc_tree = 1;
2163
2164 while (!list_empty(&rc->reloc_roots)) {
2165 reloc_root = list_entry(rc->reloc_roots.next,
2166 struct btrfs_root, root_list);
2167 list_del_init(&reloc_root->root_list);
2168
2169 root = read_fs_root(reloc_root->fs_info,
2170 reloc_root->root_key.offset);
2171 BUG_ON(IS_ERR(root));
2172 BUG_ON(root->reloc_root != reloc_root);
2173
2174 /*
2175 * set reference count to 1, so btrfs_recover_relocation
2176 * knows it should resumes merging
2177 */
2178 if (!err)
2179 btrfs_set_root_refs(&reloc_root->root_item, 1);
2180 btrfs_update_reloc_root(trans, root);
2181
2182 list_add(&reloc_root->root_list, &reloc_roots);
2183 }
2184
2185 list_splice(&reloc_roots, &rc->reloc_roots);
2186
2187 if (!err)
2188 btrfs_commit_transaction(trans, rc->extent_root);
2189 else
2190 btrfs_end_transaction(trans, rc->extent_root);
2191 return err;
2192 }
2193
2194 static noinline_for_stack
2195 int merge_reloc_roots(struct reloc_control *rc)
2196 {
2197 struct btrfs_root *root;
2198 struct btrfs_root *reloc_root;
2199 LIST_HEAD(reloc_roots);
2200 int found = 0;
2201 int ret;
2202 again:
2203 root = rc->extent_root;
2204 mutex_lock(&root->fs_info->trans_mutex);
2205 list_splice_init(&rc->reloc_roots, &reloc_roots);
2206 mutex_unlock(&root->fs_info->trans_mutex);
2207
2208 while (!list_empty(&reloc_roots)) {
2209 found = 1;
2210 reloc_root = list_entry(reloc_roots.next,
2211 struct btrfs_root, root_list);
2212
2213 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2214 root = read_fs_root(reloc_root->fs_info,
2215 reloc_root->root_key.offset);
2216 BUG_ON(IS_ERR(root));
2217 BUG_ON(root->reloc_root != reloc_root);
2218
2219 ret = merge_reloc_root(rc, root);
2220 BUG_ON(ret);
2221 } else {
2222 list_del_init(&reloc_root->root_list);
2223 }
2224 btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0);
2225 }
2226
2227 if (found) {
2228 found = 0;
2229 goto again;
2230 }
2231 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2232 return 0;
2233 }
2234
2235 static void free_block_list(struct rb_root *blocks)
2236 {
2237 struct tree_block *block;
2238 struct rb_node *rb_node;
2239 while ((rb_node = rb_first(blocks))) {
2240 block = rb_entry(rb_node, struct tree_block, rb_node);
2241 rb_erase(rb_node, blocks);
2242 kfree(block);
2243 }
2244 }
2245
2246 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2247 struct btrfs_root *reloc_root)
2248 {
2249 struct btrfs_root *root;
2250
2251 if (reloc_root->last_trans == trans->transid)
2252 return 0;
2253
2254 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2255 BUG_ON(IS_ERR(root));
2256 BUG_ON(root->reloc_root != reloc_root);
2257
2258 return btrfs_record_root_in_trans(trans, root);
2259 }
2260
2261 static noinline_for_stack
2262 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2263 struct reloc_control *rc,
2264 struct backref_node *node,
2265 struct backref_edge *edges[], int *nr)
2266 {
2267 struct backref_node *next;
2268 struct btrfs_root *root;
2269 int index = 0;
2270
2271 next = node;
2272 while (1) {
2273 cond_resched();
2274 next = walk_up_backref(next, edges, &index);
2275 root = next->root;
2276 BUG_ON(!root);
2277 BUG_ON(!root->ref_cows);
2278
2279 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2280 record_reloc_root_in_trans(trans, root);
2281 break;
2282 }
2283
2284 btrfs_record_root_in_trans(trans, root);
2285 root = root->reloc_root;
2286
2287 if (next->new_bytenr != root->node->start) {
2288 BUG_ON(next->new_bytenr);
2289 BUG_ON(!list_empty(&next->list));
2290 next->new_bytenr = root->node->start;
2291 next->root = root;
2292 list_add_tail(&next->list,
2293 &rc->backref_cache.changed);
2294 __mark_block_processed(rc, next);
2295 break;
2296 }
2297
2298 WARN_ON(1);
2299 root = NULL;
2300 next = walk_down_backref(edges, &index);
2301 if (!next || next->level <= node->level)
2302 break;
2303 }
2304 if (!root)
2305 return NULL;
2306
2307 *nr = index;
2308 next = node;
2309 /* setup backref node path for btrfs_reloc_cow_block */
2310 while (1) {
2311 rc->backref_cache.path[next->level] = next;
2312 if (--index < 0)
2313 break;
2314 next = edges[index]->node[UPPER];
2315 }
2316 return root;
2317 }
2318
2319 /*
2320 * select a tree root for relocation. return NULL if the block
2321 * is reference counted. we should use do_relocation() in this
2322 * case. return a tree root pointer if the block isn't reference
2323 * counted. return -ENOENT if the block is root of reloc tree.
2324 */
2325 static noinline_for_stack
2326 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2327 struct backref_node *node)
2328 {
2329 struct backref_node *next;
2330 struct btrfs_root *root;
2331 struct btrfs_root *fs_root = NULL;
2332 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2333 int index = 0;
2334
2335 next = node;
2336 while (1) {
2337 cond_resched();
2338 next = walk_up_backref(next, edges, &index);
2339 root = next->root;
2340 BUG_ON(!root);
2341
2342 /* no other choice for non-refernce counted tree */
2343 if (!root->ref_cows)
2344 return root;
2345
2346 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2347 fs_root = root;
2348
2349 if (next != node)
2350 return NULL;
2351
2352 next = walk_down_backref(edges, &index);
2353 if (!next || next->level <= node->level)
2354 break;
2355 }
2356
2357 if (!fs_root)
2358 return ERR_PTR(-ENOENT);
2359 return fs_root;
2360 }
2361
2362 static noinline_for_stack
2363 u64 calcu_metadata_size(struct reloc_control *rc,
2364 struct backref_node *node, int reserve)
2365 {
2366 struct backref_node *next = node;
2367 struct backref_edge *edge;
2368 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2369 u64 num_bytes = 0;
2370 int index = 0;
2371
2372 BUG_ON(reserve && node->processed);
2373
2374 while (next) {
2375 cond_resched();
2376 while (1) {
2377 if (next->processed && (reserve || next != node))
2378 break;
2379
2380 num_bytes += btrfs_level_size(rc->extent_root,
2381 next->level);
2382
2383 if (list_empty(&next->upper))
2384 break;
2385
2386 edge = list_entry(next->upper.next,
2387 struct backref_edge, list[LOWER]);
2388 edges[index++] = edge;
2389 next = edge->node[UPPER];
2390 }
2391 next = walk_down_backref(edges, &index);
2392 }
2393 return num_bytes;
2394 }
2395
2396 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2397 struct reloc_control *rc,
2398 struct backref_node *node)
2399 {
2400 struct btrfs_root *root = rc->extent_root;
2401 u64 num_bytes;
2402 int ret;
2403
2404 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2405
2406 trans->block_rsv = rc->block_rsv;
2407 ret = btrfs_block_rsv_add(trans, root, rc->block_rsv, num_bytes,
2408 &rc->block_rsv_retries);
2409 if (ret) {
2410 if (ret == -EAGAIN)
2411 rc->commit_transaction = 1;
2412 return ret;
2413 }
2414
2415 rc->block_rsv_retries = 0;
2416 return 0;
2417 }
2418
2419 static void release_metadata_space(struct reloc_control *rc,
2420 struct backref_node *node)
2421 {
2422 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2423 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2424 }
2425
2426 /*
2427 * relocate a block tree, and then update pointers in upper level
2428 * blocks that reference the block to point to the new location.
2429 *
2430 * if called by link_to_upper, the block has already been relocated.
2431 * in that case this function just updates pointers.
2432 */
2433 static int do_relocation(struct btrfs_trans_handle *trans,
2434 struct reloc_control *rc,
2435 struct backref_node *node,
2436 struct btrfs_key *key,
2437 struct btrfs_path *path, int lowest)
2438 {
2439 struct backref_node *upper;
2440 struct backref_edge *edge;
2441 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2442 struct btrfs_root *root;
2443 struct extent_buffer *eb;
2444 u32 blocksize;
2445 u64 bytenr;
2446 u64 generation;
2447 int nr;
2448 int slot;
2449 int ret;
2450 int err = 0;
2451
2452 BUG_ON(lowest && node->eb);
2453
2454 path->lowest_level = node->level + 1;
2455 rc->backref_cache.path[node->level] = node;
2456 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2457 cond_resched();
2458
2459 upper = edge->node[UPPER];
2460 root = select_reloc_root(trans, rc, upper, edges, &nr);
2461 BUG_ON(!root);
2462
2463 if (upper->eb && !upper->locked) {
2464 if (!lowest) {
2465 ret = btrfs_bin_search(upper->eb, key,
2466 upper->level, &slot);
2467 BUG_ON(ret);
2468 bytenr = btrfs_node_blockptr(upper->eb, slot);
2469 if (node->eb->start == bytenr)
2470 goto next;
2471 }
2472 drop_node_buffer(upper);
2473 }
2474
2475 if (!upper->eb) {
2476 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2477 if (ret < 0) {
2478 err = ret;
2479 break;
2480 }
2481 BUG_ON(ret > 0);
2482
2483 if (!upper->eb) {
2484 upper->eb = path->nodes[upper->level];
2485 path->nodes[upper->level] = NULL;
2486 } else {
2487 BUG_ON(upper->eb != path->nodes[upper->level]);
2488 }
2489
2490 upper->locked = 1;
2491 path->locks[upper->level] = 0;
2492
2493 slot = path->slots[upper->level];
2494 btrfs_release_path(NULL, path);
2495 } else {
2496 ret = btrfs_bin_search(upper->eb, key, upper->level,
2497 &slot);
2498 BUG_ON(ret);
2499 }
2500
2501 bytenr = btrfs_node_blockptr(upper->eb, slot);
2502 if (lowest) {
2503 BUG_ON(bytenr != node->bytenr);
2504 } else {
2505 if (node->eb->start == bytenr)
2506 goto next;
2507 }
2508
2509 blocksize = btrfs_level_size(root, node->level);
2510 generation = btrfs_node_ptr_generation(upper->eb, slot);
2511 eb = read_tree_block(root, bytenr, blocksize, generation);
2512 btrfs_tree_lock(eb);
2513 btrfs_set_lock_blocking(eb);
2514
2515 if (!node->eb) {
2516 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2517 slot, &eb);
2518 btrfs_tree_unlock(eb);
2519 free_extent_buffer(eb);
2520 if (ret < 0) {
2521 err = ret;
2522 goto next;
2523 }
2524 BUG_ON(node->eb != eb);
2525 } else {
2526 btrfs_set_node_blockptr(upper->eb, slot,
2527 node->eb->start);
2528 btrfs_set_node_ptr_generation(upper->eb, slot,
2529 trans->transid);
2530 btrfs_mark_buffer_dirty(upper->eb);
2531
2532 ret = btrfs_inc_extent_ref(trans, root,
2533 node->eb->start, blocksize,
2534 upper->eb->start,
2535 btrfs_header_owner(upper->eb),
2536 node->level, 0);
2537 BUG_ON(ret);
2538
2539 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2540 BUG_ON(ret);
2541 }
2542 next:
2543 if (!upper->pending)
2544 drop_node_buffer(upper);
2545 else
2546 unlock_node_buffer(upper);
2547 if (err)
2548 break;
2549 }
2550
2551 if (!err && node->pending) {
2552 drop_node_buffer(node);
2553 list_move_tail(&node->list, &rc->backref_cache.changed);
2554 node->pending = 0;
2555 }
2556
2557 path->lowest_level = 0;
2558 BUG_ON(err == -ENOSPC);
2559 return err;
2560 }
2561
2562 static int link_to_upper(struct btrfs_trans_handle *trans,
2563 struct reloc_control *rc,
2564 struct backref_node *node,
2565 struct btrfs_path *path)
2566 {
2567 struct btrfs_key key;
2568
2569 btrfs_node_key_to_cpu(node->eb, &key, 0);
2570 return do_relocation(trans, rc, node, &key, path, 0);
2571 }
2572
2573 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2574 struct reloc_control *rc,
2575 struct btrfs_path *path, int err)
2576 {
2577 LIST_HEAD(list);
2578 struct backref_cache *cache = &rc->backref_cache;
2579 struct backref_node *node;
2580 int level;
2581 int ret;
2582
2583 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2584 while (!list_empty(&cache->pending[level])) {
2585 node = list_entry(cache->pending[level].next,
2586 struct backref_node, list);
2587 list_move_tail(&node->list, &list);
2588 BUG_ON(!node->pending);
2589
2590 if (!err) {
2591 ret = link_to_upper(trans, rc, node, path);
2592 if (ret < 0)
2593 err = ret;
2594 }
2595 }
2596 list_splice_init(&list, &cache->pending[level]);
2597 }
2598 return err;
2599 }
2600
2601 static void mark_block_processed(struct reloc_control *rc,
2602 u64 bytenr, u32 blocksize)
2603 {
2604 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2605 EXTENT_DIRTY, GFP_NOFS);
2606 }
2607
2608 static void __mark_block_processed(struct reloc_control *rc,
2609 struct backref_node *node)
2610 {
2611 u32 blocksize;
2612 if (node->level == 0 ||
2613 in_block_group(node->bytenr, rc->block_group)) {
2614 blocksize = btrfs_level_size(rc->extent_root, node->level);
2615 mark_block_processed(rc, node->bytenr, blocksize);
2616 }
2617 node->processed = 1;
2618 }
2619
2620 /*
2621 * mark a block and all blocks directly/indirectly reference the block
2622 * as processed.
2623 */
2624 static void update_processed_blocks(struct reloc_control *rc,
2625 struct backref_node *node)
2626 {
2627 struct backref_node *next = node;
2628 struct backref_edge *edge;
2629 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2630 int index = 0;
2631
2632 while (next) {
2633 cond_resched();
2634 while (1) {
2635 if (next->processed)
2636 break;
2637
2638 __mark_block_processed(rc, next);
2639
2640 if (list_empty(&next->upper))
2641 break;
2642
2643 edge = list_entry(next->upper.next,
2644 struct backref_edge, list[LOWER]);
2645 edges[index++] = edge;
2646 next = edge->node[UPPER];
2647 }
2648 next = walk_down_backref(edges, &index);
2649 }
2650 }
2651
2652 static int tree_block_processed(u64 bytenr, u32 blocksize,
2653 struct reloc_control *rc)
2654 {
2655 if (test_range_bit(&rc->processed_blocks, bytenr,
2656 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2657 return 1;
2658 return 0;
2659 }
2660
2661 static int get_tree_block_key(struct reloc_control *rc,
2662 struct tree_block *block)
2663 {
2664 struct extent_buffer *eb;
2665
2666 BUG_ON(block->key_ready);
2667 eb = read_tree_block(rc->extent_root, block->bytenr,
2668 block->key.objectid, block->key.offset);
2669 WARN_ON(btrfs_header_level(eb) != block->level);
2670 if (block->level == 0)
2671 btrfs_item_key_to_cpu(eb, &block->key, 0);
2672 else
2673 btrfs_node_key_to_cpu(eb, &block->key, 0);
2674 free_extent_buffer(eb);
2675 block->key_ready = 1;
2676 return 0;
2677 }
2678
2679 static int reada_tree_block(struct reloc_control *rc,
2680 struct tree_block *block)
2681 {
2682 BUG_ON(block->key_ready);
2683 readahead_tree_block(rc->extent_root, block->bytenr,
2684 block->key.objectid, block->key.offset);
2685 return 0;
2686 }
2687
2688 /*
2689 * helper function to relocate a tree block
2690 */
2691 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2692 struct reloc_control *rc,
2693 struct backref_node *node,
2694 struct btrfs_key *key,
2695 struct btrfs_path *path)
2696 {
2697 struct btrfs_root *root;
2698 int release = 0;
2699 int ret = 0;
2700
2701 if (!node)
2702 return 0;
2703
2704 BUG_ON(node->processed);
2705 root = select_one_root(trans, node);
2706 if (root == ERR_PTR(-ENOENT)) {
2707 update_processed_blocks(rc, node);
2708 goto out;
2709 }
2710
2711 if (!root || root->ref_cows) {
2712 ret = reserve_metadata_space(trans, rc, node);
2713 if (ret)
2714 goto out;
2715 release = 1;
2716 }
2717
2718 if (root) {
2719 if (root->ref_cows) {
2720 BUG_ON(node->new_bytenr);
2721 BUG_ON(!list_empty(&node->list));
2722 btrfs_record_root_in_trans(trans, root);
2723 root = root->reloc_root;
2724 node->new_bytenr = root->node->start;
2725 node->root = root;
2726 list_add_tail(&node->list, &rc->backref_cache.changed);
2727 } else {
2728 path->lowest_level = node->level;
2729 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2730 btrfs_release_path(root, path);
2731 if (ret > 0)
2732 ret = 0;
2733 }
2734 if (!ret)
2735 update_processed_blocks(rc, node);
2736 } else {
2737 ret = do_relocation(trans, rc, node, key, path, 1);
2738 }
2739 out:
2740 if (ret || node->level == 0 || node->cowonly) {
2741 if (release)
2742 release_metadata_space(rc, node);
2743 remove_backref_node(&rc->backref_cache, node);
2744 }
2745 return ret;
2746 }
2747
2748 /*
2749 * relocate a list of blocks
2750 */
2751 static noinline_for_stack
2752 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2753 struct reloc_control *rc, struct rb_root *blocks)
2754 {
2755 struct backref_node *node;
2756 struct btrfs_path *path;
2757 struct tree_block *block;
2758 struct rb_node *rb_node;
2759 int ret;
2760 int err = 0;
2761
2762 path = btrfs_alloc_path();
2763 if (!path)
2764 return -ENOMEM;
2765
2766 rb_node = rb_first(blocks);
2767 while (rb_node) {
2768 block = rb_entry(rb_node, struct tree_block, rb_node);
2769 if (!block->key_ready)
2770 reada_tree_block(rc, block);
2771 rb_node = rb_next(rb_node);
2772 }
2773
2774 rb_node = rb_first(blocks);
2775 while (rb_node) {
2776 block = rb_entry(rb_node, struct tree_block, rb_node);
2777 if (!block->key_ready)
2778 get_tree_block_key(rc, block);
2779 rb_node = rb_next(rb_node);
2780 }
2781
2782 rb_node = rb_first(blocks);
2783 while (rb_node) {
2784 block = rb_entry(rb_node, struct tree_block, rb_node);
2785
2786 node = build_backref_tree(rc, &block->key,
2787 block->level, block->bytenr);
2788 if (IS_ERR(node)) {
2789 err = PTR_ERR(node);
2790 goto out;
2791 }
2792
2793 ret = relocate_tree_block(trans, rc, node, &block->key,
2794 path);
2795 if (ret < 0) {
2796 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2797 err = ret;
2798 goto out;
2799 }
2800 rb_node = rb_next(rb_node);
2801 }
2802 out:
2803 free_block_list(blocks);
2804 err = finish_pending_nodes(trans, rc, path, err);
2805
2806 btrfs_free_path(path);
2807 return err;
2808 }
2809
2810 static noinline_for_stack
2811 int prealloc_file_extent_cluster(struct inode *inode,
2812 struct file_extent_cluster *cluster)
2813 {
2814 u64 alloc_hint = 0;
2815 u64 start;
2816 u64 end;
2817 u64 offset = BTRFS_I(inode)->index_cnt;
2818 u64 num_bytes;
2819 int nr = 0;
2820 int ret = 0;
2821
2822 BUG_ON(cluster->start != cluster->boundary[0]);
2823 mutex_lock(&inode->i_mutex);
2824
2825 ret = btrfs_check_data_free_space(inode, cluster->end +
2826 1 - cluster->start);
2827 if (ret)
2828 goto out;
2829
2830 while (nr < cluster->nr) {
2831 start = cluster->boundary[nr] - offset;
2832 if (nr + 1 < cluster->nr)
2833 end = cluster->boundary[nr + 1] - 1 - offset;
2834 else
2835 end = cluster->end - offset;
2836
2837 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2838 num_bytes = end + 1 - start;
2839 ret = btrfs_prealloc_file_range(inode, 0, start,
2840 num_bytes, num_bytes,
2841 end + 1, &alloc_hint);
2842 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2843 if (ret)
2844 break;
2845 nr++;
2846 }
2847 btrfs_free_reserved_data_space(inode, cluster->end +
2848 1 - cluster->start);
2849 out:
2850 mutex_unlock(&inode->i_mutex);
2851 return ret;
2852 }
2853
2854 static noinline_for_stack
2855 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
2856 u64 block_start)
2857 {
2858 struct btrfs_root *root = BTRFS_I(inode)->root;
2859 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2860 struct extent_map *em;
2861 int ret = 0;
2862
2863 em = alloc_extent_map(GFP_NOFS);
2864 if (!em)
2865 return -ENOMEM;
2866
2867 em->start = start;
2868 em->len = end + 1 - start;
2869 em->block_len = em->len;
2870 em->block_start = block_start;
2871 em->bdev = root->fs_info->fs_devices->latest_bdev;
2872 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2873
2874 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2875 while (1) {
2876 write_lock(&em_tree->lock);
2877 ret = add_extent_mapping(em_tree, em);
2878 write_unlock(&em_tree->lock);
2879 if (ret != -EEXIST) {
2880 free_extent_map(em);
2881 break;
2882 }
2883 btrfs_drop_extent_cache(inode, start, end, 0);
2884 }
2885 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2886 return ret;
2887 }
2888
2889 static int relocate_file_extent_cluster(struct inode *inode,
2890 struct file_extent_cluster *cluster)
2891 {
2892 u64 page_start;
2893 u64 page_end;
2894 u64 offset = BTRFS_I(inode)->index_cnt;
2895 unsigned long index;
2896 unsigned long last_index;
2897 struct page *page;
2898 struct file_ra_state *ra;
2899 int nr = 0;
2900 int ret = 0;
2901
2902 if (!cluster->nr)
2903 return 0;
2904
2905 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2906 if (!ra)
2907 return -ENOMEM;
2908
2909 ret = prealloc_file_extent_cluster(inode, cluster);
2910 if (ret)
2911 goto out;
2912
2913 file_ra_state_init(ra, inode->i_mapping);
2914
2915 ret = setup_extent_mapping(inode, cluster->start - offset,
2916 cluster->end - offset, cluster->start);
2917 if (ret)
2918 goto out;
2919
2920 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
2921 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
2922 while (index <= last_index) {
2923 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
2924 if (ret)
2925 goto out;
2926
2927 page = find_lock_page(inode->i_mapping, index);
2928 if (!page) {
2929 page_cache_sync_readahead(inode->i_mapping,
2930 ra, NULL, index,
2931 last_index + 1 - index);
2932 page = grab_cache_page(inode->i_mapping, index);
2933 if (!page) {
2934 btrfs_delalloc_release_metadata(inode,
2935 PAGE_CACHE_SIZE);
2936 ret = -ENOMEM;
2937 goto out;
2938 }
2939 }
2940
2941 if (PageReadahead(page)) {
2942 page_cache_async_readahead(inode->i_mapping,
2943 ra, NULL, page, index,
2944 last_index + 1 - index);
2945 }
2946
2947 if (!PageUptodate(page)) {
2948 btrfs_readpage(NULL, page);
2949 lock_page(page);
2950 if (!PageUptodate(page)) {
2951 unlock_page(page);
2952 page_cache_release(page);
2953 btrfs_delalloc_release_metadata(inode,
2954 PAGE_CACHE_SIZE);
2955 ret = -EIO;
2956 goto out;
2957 }
2958 }
2959
2960 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2961 page_end = page_start + PAGE_CACHE_SIZE - 1;
2962
2963 lock_extent(&BTRFS_I(inode)->io_tree,
2964 page_start, page_end, GFP_NOFS);
2965
2966 set_page_extent_mapped(page);
2967
2968 if (nr < cluster->nr &&
2969 page_start + offset == cluster->boundary[nr]) {
2970 set_extent_bits(&BTRFS_I(inode)->io_tree,
2971 page_start, page_end,
2972 EXTENT_BOUNDARY, GFP_NOFS);
2973 nr++;
2974 }
2975
2976 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
2977 set_page_dirty(page);
2978
2979 unlock_extent(&BTRFS_I(inode)->io_tree,
2980 page_start, page_end, GFP_NOFS);
2981 unlock_page(page);
2982 page_cache_release(page);
2983
2984 index++;
2985 balance_dirty_pages_ratelimited(inode->i_mapping);
2986 btrfs_throttle(BTRFS_I(inode)->root);
2987 }
2988 WARN_ON(nr != cluster->nr);
2989 out:
2990 kfree(ra);
2991 return ret;
2992 }
2993
2994 static noinline_for_stack
2995 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
2996 struct file_extent_cluster *cluster)
2997 {
2998 int ret;
2999
3000 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3001 ret = relocate_file_extent_cluster(inode, cluster);
3002 if (ret)
3003 return ret;
3004 cluster->nr = 0;
3005 }
3006
3007 if (!cluster->nr)
3008 cluster->start = extent_key->objectid;
3009 else
3010 BUG_ON(cluster->nr >= MAX_EXTENTS);
3011 cluster->end = extent_key->objectid + extent_key->offset - 1;
3012 cluster->boundary[cluster->nr] = extent_key->objectid;
3013 cluster->nr++;
3014
3015 if (cluster->nr >= MAX_EXTENTS) {
3016 ret = relocate_file_extent_cluster(inode, cluster);
3017 if (ret)
3018 return ret;
3019 cluster->nr = 0;
3020 }
3021 return 0;
3022 }
3023
3024 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3025 static int get_ref_objectid_v0(struct reloc_control *rc,
3026 struct btrfs_path *path,
3027 struct btrfs_key *extent_key,
3028 u64 *ref_objectid, int *path_change)
3029 {
3030 struct btrfs_key key;
3031 struct extent_buffer *leaf;
3032 struct btrfs_extent_ref_v0 *ref0;
3033 int ret;
3034 int slot;
3035
3036 leaf = path->nodes[0];
3037 slot = path->slots[0];
3038 while (1) {
3039 if (slot >= btrfs_header_nritems(leaf)) {
3040 ret = btrfs_next_leaf(rc->extent_root, path);
3041 if (ret < 0)
3042 return ret;
3043 BUG_ON(ret > 0);
3044 leaf = path->nodes[0];
3045 slot = path->slots[0];
3046 if (path_change)
3047 *path_change = 1;
3048 }
3049 btrfs_item_key_to_cpu(leaf, &key, slot);
3050 if (key.objectid != extent_key->objectid)
3051 return -ENOENT;
3052
3053 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3054 slot++;
3055 continue;
3056 }
3057 ref0 = btrfs_item_ptr(leaf, slot,
3058 struct btrfs_extent_ref_v0);
3059 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3060 break;
3061 }
3062 return 0;
3063 }
3064 #endif
3065
3066 /*
3067 * helper to add a tree block to the list.
3068 * the major work is getting the generation and level of the block
3069 */
3070 static int add_tree_block(struct reloc_control *rc,
3071 struct btrfs_key *extent_key,
3072 struct btrfs_path *path,
3073 struct rb_root *blocks)
3074 {
3075 struct extent_buffer *eb;
3076 struct btrfs_extent_item *ei;
3077 struct btrfs_tree_block_info *bi;
3078 struct tree_block *block;
3079 struct rb_node *rb_node;
3080 u32 item_size;
3081 int level = -1;
3082 int generation;
3083
3084 eb = path->nodes[0];
3085 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3086
3087 if (item_size >= sizeof(*ei) + sizeof(*bi)) {
3088 ei = btrfs_item_ptr(eb, path->slots[0],
3089 struct btrfs_extent_item);
3090 bi = (struct btrfs_tree_block_info *)(ei + 1);
3091 generation = btrfs_extent_generation(eb, ei);
3092 level = btrfs_tree_block_level(eb, bi);
3093 } else {
3094 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3095 u64 ref_owner;
3096 int ret;
3097
3098 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3099 ret = get_ref_objectid_v0(rc, path, extent_key,
3100 &ref_owner, NULL);
3101 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3102 level = (int)ref_owner;
3103 /* FIXME: get real generation */
3104 generation = 0;
3105 #else
3106 BUG();
3107 #endif
3108 }
3109
3110 btrfs_release_path(rc->extent_root, path);
3111
3112 BUG_ON(level == -1);
3113
3114 block = kmalloc(sizeof(*block), GFP_NOFS);
3115 if (!block)
3116 return -ENOMEM;
3117
3118 block->bytenr = extent_key->objectid;
3119 block->key.objectid = extent_key->offset;
3120 block->key.offset = generation;
3121 block->level = level;
3122 block->key_ready = 0;
3123
3124 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3125 BUG_ON(rb_node);
3126
3127 return 0;
3128 }
3129
3130 /*
3131 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3132 */
3133 static int __add_tree_block(struct reloc_control *rc,
3134 u64 bytenr, u32 blocksize,
3135 struct rb_root *blocks)
3136 {
3137 struct btrfs_path *path;
3138 struct btrfs_key key;
3139 int ret;
3140
3141 if (tree_block_processed(bytenr, blocksize, rc))
3142 return 0;
3143
3144 if (tree_search(blocks, bytenr))
3145 return 0;
3146
3147 path = btrfs_alloc_path();
3148 if (!path)
3149 return -ENOMEM;
3150
3151 key.objectid = bytenr;
3152 key.type = BTRFS_EXTENT_ITEM_KEY;
3153 key.offset = blocksize;
3154
3155 path->search_commit_root = 1;
3156 path->skip_locking = 1;
3157 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3158 if (ret < 0)
3159 goto out;
3160 BUG_ON(ret);
3161
3162 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3163 ret = add_tree_block(rc, &key, path, blocks);
3164 out:
3165 btrfs_free_path(path);
3166 return ret;
3167 }
3168
3169 /*
3170 * helper to check if the block use full backrefs for pointers in it
3171 */
3172 static int block_use_full_backref(struct reloc_control *rc,
3173 struct extent_buffer *eb)
3174 {
3175 u64 flags;
3176 int ret;
3177
3178 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3179 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3180 return 1;
3181
3182 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3183 eb->start, eb->len, NULL, &flags);
3184 BUG_ON(ret);
3185
3186 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3187 ret = 1;
3188 else
3189 ret = 0;
3190 return ret;
3191 }
3192
3193 /*
3194 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3195 * this function scans fs tree to find blocks reference the data extent
3196 */
3197 static int find_data_references(struct reloc_control *rc,
3198 struct btrfs_key *extent_key,
3199 struct extent_buffer *leaf,
3200 struct btrfs_extent_data_ref *ref,
3201 struct rb_root *blocks)
3202 {
3203 struct btrfs_path *path;
3204 struct tree_block *block;
3205 struct btrfs_root *root;
3206 struct btrfs_file_extent_item *fi;
3207 struct rb_node *rb_node;
3208 struct btrfs_key key;
3209 u64 ref_root;
3210 u64 ref_objectid;
3211 u64 ref_offset;
3212 u32 ref_count;
3213 u32 nritems;
3214 int err = 0;
3215 int added = 0;
3216 int counted;
3217 int ret;
3218
3219 path = btrfs_alloc_path();
3220 if (!path)
3221 return -ENOMEM;
3222
3223 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3224 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3225 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3226 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3227
3228 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3229 if (IS_ERR(root)) {
3230 err = PTR_ERR(root);
3231 goto out;
3232 }
3233
3234 key.objectid = ref_objectid;
3235 key.offset = ref_offset;
3236 key.type = BTRFS_EXTENT_DATA_KEY;
3237
3238 path->search_commit_root = 1;
3239 path->skip_locking = 1;
3240 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3241 if (ret < 0) {
3242 err = ret;
3243 goto out;
3244 }
3245
3246 leaf = path->nodes[0];
3247 nritems = btrfs_header_nritems(leaf);
3248 /*
3249 * the references in tree blocks that use full backrefs
3250 * are not counted in
3251 */
3252 if (block_use_full_backref(rc, leaf))
3253 counted = 0;
3254 else
3255 counted = 1;
3256 rb_node = tree_search(blocks, leaf->start);
3257 if (rb_node) {
3258 if (counted)
3259 added = 1;
3260 else
3261 path->slots[0] = nritems;
3262 }
3263
3264 while (ref_count > 0) {
3265 while (path->slots[0] >= nritems) {
3266 ret = btrfs_next_leaf(root, path);
3267 if (ret < 0) {
3268 err = ret;
3269 goto out;
3270 }
3271 if (ret > 0) {
3272 WARN_ON(1);
3273 goto out;
3274 }
3275
3276 leaf = path->nodes[0];
3277 nritems = btrfs_header_nritems(leaf);
3278 added = 0;
3279
3280 if (block_use_full_backref(rc, leaf))
3281 counted = 0;
3282 else
3283 counted = 1;
3284 rb_node = tree_search(blocks, leaf->start);
3285 if (rb_node) {
3286 if (counted)
3287 added = 1;
3288 else
3289 path->slots[0] = nritems;
3290 }
3291 }
3292
3293 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3294 if (key.objectid != ref_objectid ||
3295 key.type != BTRFS_EXTENT_DATA_KEY) {
3296 WARN_ON(1);
3297 break;
3298 }
3299
3300 fi = btrfs_item_ptr(leaf, path->slots[0],
3301 struct btrfs_file_extent_item);
3302
3303 if (btrfs_file_extent_type(leaf, fi) ==
3304 BTRFS_FILE_EXTENT_INLINE)
3305 goto next;
3306
3307 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3308 extent_key->objectid)
3309 goto next;
3310
3311 key.offset -= btrfs_file_extent_offset(leaf, fi);
3312 if (key.offset != ref_offset)
3313 goto next;
3314
3315 if (counted)
3316 ref_count--;
3317 if (added)
3318 goto next;
3319
3320 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3321 block = kmalloc(sizeof(*block), GFP_NOFS);
3322 if (!block) {
3323 err = -ENOMEM;
3324 break;
3325 }
3326 block->bytenr = leaf->start;
3327 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3328 block->level = 0;
3329 block->key_ready = 1;
3330 rb_node = tree_insert(blocks, block->bytenr,
3331 &block->rb_node);
3332 BUG_ON(rb_node);
3333 }
3334 if (counted)
3335 added = 1;
3336 else
3337 path->slots[0] = nritems;
3338 next:
3339 path->slots[0]++;
3340
3341 }
3342 out:
3343 btrfs_free_path(path);
3344 return err;
3345 }
3346
3347 /*
3348 * hepler to find all tree blocks that reference a given data extent
3349 */
3350 static noinline_for_stack
3351 int add_data_references(struct reloc_control *rc,
3352 struct btrfs_key *extent_key,
3353 struct btrfs_path *path,
3354 struct rb_root *blocks)
3355 {
3356 struct btrfs_key key;
3357 struct extent_buffer *eb;
3358 struct btrfs_extent_data_ref *dref;
3359 struct btrfs_extent_inline_ref *iref;
3360 unsigned long ptr;
3361 unsigned long end;
3362 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3363 int ret;
3364 int err = 0;
3365
3366 eb = path->nodes[0];
3367 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3368 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3369 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3370 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3371 ptr = end;
3372 else
3373 #endif
3374 ptr += sizeof(struct btrfs_extent_item);
3375
3376 while (ptr < end) {
3377 iref = (struct btrfs_extent_inline_ref *)ptr;
3378 key.type = btrfs_extent_inline_ref_type(eb, iref);
3379 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3380 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3381 ret = __add_tree_block(rc, key.offset, blocksize,
3382 blocks);
3383 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3384 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3385 ret = find_data_references(rc, extent_key,
3386 eb, dref, blocks);
3387 } else {
3388 BUG();
3389 }
3390 ptr += btrfs_extent_inline_ref_size(key.type);
3391 }
3392 WARN_ON(ptr > end);
3393
3394 while (1) {
3395 cond_resched();
3396 eb = path->nodes[0];
3397 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3398 ret = btrfs_next_leaf(rc->extent_root, path);
3399 if (ret < 0) {
3400 err = ret;
3401 break;
3402 }
3403 if (ret > 0)
3404 break;
3405 eb = path->nodes[0];
3406 }
3407
3408 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3409 if (key.objectid != extent_key->objectid)
3410 break;
3411
3412 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3413 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3414 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3415 #else
3416 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3417 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3418 #endif
3419 ret = __add_tree_block(rc, key.offset, blocksize,
3420 blocks);
3421 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3422 dref = btrfs_item_ptr(eb, path->slots[0],
3423 struct btrfs_extent_data_ref);
3424 ret = find_data_references(rc, extent_key,
3425 eb, dref, blocks);
3426 } else {
3427 ret = 0;
3428 }
3429 if (ret) {
3430 err = ret;
3431 break;
3432 }
3433 path->slots[0]++;
3434 }
3435 btrfs_release_path(rc->extent_root, path);
3436 if (err)
3437 free_block_list(blocks);
3438 return err;
3439 }
3440
3441 /*
3442 * hepler to find next unprocessed extent
3443 */
3444 static noinline_for_stack
3445 int find_next_extent(struct btrfs_trans_handle *trans,
3446 struct reloc_control *rc, struct btrfs_path *path,
3447 struct btrfs_key *extent_key)
3448 {
3449 struct btrfs_key key;
3450 struct extent_buffer *leaf;
3451 u64 start, end, last;
3452 int ret;
3453
3454 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3455 while (1) {
3456 cond_resched();
3457 if (rc->search_start >= last) {
3458 ret = 1;
3459 break;
3460 }
3461
3462 key.objectid = rc->search_start;
3463 key.type = BTRFS_EXTENT_ITEM_KEY;
3464 key.offset = 0;
3465
3466 path->search_commit_root = 1;
3467 path->skip_locking = 1;
3468 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3469 0, 0);
3470 if (ret < 0)
3471 break;
3472 next:
3473 leaf = path->nodes[0];
3474 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3475 ret = btrfs_next_leaf(rc->extent_root, path);
3476 if (ret != 0)
3477 break;
3478 leaf = path->nodes[0];
3479 }
3480
3481 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3482 if (key.objectid >= last) {
3483 ret = 1;
3484 break;
3485 }
3486
3487 if (key.type != BTRFS_EXTENT_ITEM_KEY ||
3488 key.objectid + key.offset <= rc->search_start) {
3489 path->slots[0]++;
3490 goto next;
3491 }
3492
3493 ret = find_first_extent_bit(&rc->processed_blocks,
3494 key.objectid, &start, &end,
3495 EXTENT_DIRTY);
3496
3497 if (ret == 0 && start <= key.objectid) {
3498 btrfs_release_path(rc->extent_root, path);
3499 rc->search_start = end + 1;
3500 } else {
3501 rc->search_start = key.objectid + key.offset;
3502 memcpy(extent_key, &key, sizeof(key));
3503 return 0;
3504 }
3505 }
3506 btrfs_release_path(rc->extent_root, path);
3507 return ret;
3508 }
3509
3510 static void set_reloc_control(struct reloc_control *rc)
3511 {
3512 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3513 mutex_lock(&fs_info->trans_mutex);
3514 fs_info->reloc_ctl = rc;
3515 mutex_unlock(&fs_info->trans_mutex);
3516 }
3517
3518 static void unset_reloc_control(struct reloc_control *rc)
3519 {
3520 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3521 mutex_lock(&fs_info->trans_mutex);
3522 fs_info->reloc_ctl = NULL;
3523 mutex_unlock(&fs_info->trans_mutex);
3524 }
3525
3526 static int check_extent_flags(u64 flags)
3527 {
3528 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3529 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3530 return 1;
3531 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3532 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3533 return 1;
3534 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3535 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3536 return 1;
3537 return 0;
3538 }
3539
3540 static noinline_for_stack
3541 int prepare_to_relocate(struct reloc_control *rc)
3542 {
3543 struct btrfs_trans_handle *trans;
3544 int ret;
3545
3546 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root);
3547 if (!rc->block_rsv)
3548 return -ENOMEM;
3549
3550 /*
3551 * reserve some space for creating reloc trees.
3552 * btrfs_init_reloc_root will use them when there
3553 * is no reservation in transaction handle.
3554 */
3555 ret = btrfs_block_rsv_add(NULL, rc->extent_root, rc->block_rsv,
3556 rc->extent_root->nodesize * 256,
3557 &rc->block_rsv_retries);
3558 if (ret)
3559 return ret;
3560
3561 rc->block_rsv->refill_used = 1;
3562 btrfs_add_durable_block_rsv(rc->extent_root->fs_info, rc->block_rsv);
3563
3564 memset(&rc->cluster, 0, sizeof(rc->cluster));
3565 rc->search_start = rc->block_group->key.objectid;
3566 rc->extents_found = 0;
3567 rc->nodes_relocated = 0;
3568 rc->merging_rsv_size = 0;
3569 rc->block_rsv_retries = 0;
3570
3571 rc->create_reloc_tree = 1;
3572 set_reloc_control(rc);
3573
3574 trans = btrfs_join_transaction(rc->extent_root, 1);
3575 btrfs_commit_transaction(trans, rc->extent_root);
3576 return 0;
3577 }
3578
3579 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3580 {
3581 struct rb_root blocks = RB_ROOT;
3582 struct btrfs_key key;
3583 struct btrfs_trans_handle *trans = NULL;
3584 struct btrfs_path *path;
3585 struct btrfs_extent_item *ei;
3586 unsigned long nr;
3587 u64 flags;
3588 u32 item_size;
3589 int ret;
3590 int err = 0;
3591
3592 path = btrfs_alloc_path();
3593 if (!path)
3594 return -ENOMEM;
3595
3596 ret = prepare_to_relocate(rc);
3597 if (ret) {
3598 err = ret;
3599 goto out_free;
3600 }
3601
3602 while (1) {
3603 trans = btrfs_start_transaction(rc->extent_root, 0);
3604
3605 if (update_backref_cache(trans, &rc->backref_cache)) {
3606 btrfs_end_transaction(trans, rc->extent_root);
3607 continue;
3608 }
3609
3610 ret = find_next_extent(trans, rc, path, &key);
3611 if (ret < 0)
3612 err = ret;
3613 if (ret != 0)
3614 break;
3615
3616 rc->extents_found++;
3617
3618 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3619 struct btrfs_extent_item);
3620 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3621 if (item_size >= sizeof(*ei)) {
3622 flags = btrfs_extent_flags(path->nodes[0], ei);
3623 ret = check_extent_flags(flags);
3624 BUG_ON(ret);
3625
3626 } else {
3627 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3628 u64 ref_owner;
3629 int path_change = 0;
3630
3631 BUG_ON(item_size !=
3632 sizeof(struct btrfs_extent_item_v0));
3633 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3634 &path_change);
3635 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3636 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3637 else
3638 flags = BTRFS_EXTENT_FLAG_DATA;
3639
3640 if (path_change) {
3641 btrfs_release_path(rc->extent_root, path);
3642
3643 path->search_commit_root = 1;
3644 path->skip_locking = 1;
3645 ret = btrfs_search_slot(NULL, rc->extent_root,
3646 &key, path, 0, 0);
3647 if (ret < 0) {
3648 err = ret;
3649 break;
3650 }
3651 BUG_ON(ret > 0);
3652 }
3653 #else
3654 BUG();
3655 #endif
3656 }
3657
3658 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3659 ret = add_tree_block(rc, &key, path, &blocks);
3660 } else if (rc->stage == UPDATE_DATA_PTRS &&
3661 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3662 ret = add_data_references(rc, &key, path, &blocks);
3663 } else {
3664 btrfs_release_path(rc->extent_root, path);
3665 ret = 0;
3666 }
3667 if (ret < 0) {
3668 err = ret;
3669 break;
3670 }
3671
3672 if (!RB_EMPTY_ROOT(&blocks)) {
3673 ret = relocate_tree_blocks(trans, rc, &blocks);
3674 if (ret < 0) {
3675 if (ret != -EAGAIN) {
3676 err = ret;
3677 break;
3678 }
3679 rc->extents_found--;
3680 rc->search_start = key.objectid;
3681 }
3682 }
3683
3684 ret = btrfs_block_rsv_check(trans, rc->extent_root,
3685 rc->block_rsv, 0, 5);
3686 if (ret < 0) {
3687 if (ret != -EAGAIN) {
3688 err = ret;
3689 WARN_ON(1);
3690 break;
3691 }
3692 rc->commit_transaction = 1;
3693 }
3694
3695 if (rc->commit_transaction) {
3696 rc->commit_transaction = 0;
3697 ret = btrfs_commit_transaction(trans, rc->extent_root);
3698 BUG_ON(ret);
3699 } else {
3700 nr = trans->blocks_used;
3701 btrfs_end_transaction_throttle(trans, rc->extent_root);
3702 btrfs_btree_balance_dirty(rc->extent_root, nr);
3703 }
3704 trans = NULL;
3705
3706 if (rc->stage == MOVE_DATA_EXTENTS &&
3707 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3708 rc->found_file_extent = 1;
3709 ret = relocate_data_extent(rc->data_inode,
3710 &key, &rc->cluster);
3711 if (ret < 0) {
3712 err = ret;
3713 break;
3714 }
3715 }
3716 }
3717
3718 btrfs_release_path(rc->extent_root, path);
3719 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3720 GFP_NOFS);
3721
3722 if (trans) {
3723 nr = trans->blocks_used;
3724 btrfs_end_transaction_throttle(trans, rc->extent_root);
3725 btrfs_btree_balance_dirty(rc->extent_root, nr);
3726 }
3727
3728 if (!err) {
3729 ret = relocate_file_extent_cluster(rc->data_inode,
3730 &rc->cluster);
3731 if (ret < 0)
3732 err = ret;
3733 }
3734
3735 rc->create_reloc_tree = 0;
3736 set_reloc_control(rc);
3737
3738 backref_cache_cleanup(&rc->backref_cache);
3739 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3740
3741 err = prepare_to_merge(rc, err);
3742
3743 merge_reloc_roots(rc);
3744
3745 rc->merge_reloc_tree = 0;
3746 unset_reloc_control(rc);
3747 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3748
3749 /* get rid of pinned extents */
3750 trans = btrfs_join_transaction(rc->extent_root, 1);
3751 btrfs_commit_transaction(trans, rc->extent_root);
3752 out_free:
3753 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
3754 btrfs_free_path(path);
3755 return err;
3756 }
3757
3758 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3759 struct btrfs_root *root, u64 objectid)
3760 {
3761 struct btrfs_path *path;
3762 struct btrfs_inode_item *item;
3763 struct extent_buffer *leaf;
3764 int ret;
3765
3766 path = btrfs_alloc_path();
3767 if (!path)
3768 return -ENOMEM;
3769
3770 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3771 if (ret)
3772 goto out;
3773
3774 leaf = path->nodes[0];
3775 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3776 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
3777 btrfs_set_inode_generation(leaf, item, 1);
3778 btrfs_set_inode_size(leaf, item, 0);
3779 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3780 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3781 BTRFS_INODE_PREALLOC);
3782 btrfs_mark_buffer_dirty(leaf);
3783 btrfs_release_path(root, path);
3784 out:
3785 btrfs_free_path(path);
3786 return ret;
3787 }
3788
3789 /*
3790 * helper to create inode for data relocation.
3791 * the inode is in data relocation tree and its link count is 0
3792 */
3793 static noinline_for_stack
3794 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3795 struct btrfs_block_group_cache *group)
3796 {
3797 struct inode *inode = NULL;
3798 struct btrfs_trans_handle *trans;
3799 struct btrfs_root *root;
3800 struct btrfs_key key;
3801 unsigned long nr;
3802 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
3803 int err = 0;
3804
3805 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
3806 if (IS_ERR(root))
3807 return ERR_CAST(root);
3808
3809 trans = btrfs_start_transaction(root, 6);
3810 if (IS_ERR(trans))
3811 return ERR_CAST(trans);
3812
3813 err = btrfs_find_free_objectid(trans, root, objectid, &objectid);
3814 if (err)
3815 goto out;
3816
3817 err = __insert_orphan_inode(trans, root, objectid);
3818 BUG_ON(err);
3819
3820 key.objectid = objectid;
3821 key.type = BTRFS_INODE_ITEM_KEY;
3822 key.offset = 0;
3823 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
3824 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
3825 BTRFS_I(inode)->index_cnt = group->key.objectid;
3826
3827 err = btrfs_orphan_add(trans, inode);
3828 out:
3829 nr = trans->blocks_used;
3830 btrfs_end_transaction(trans, root);
3831 btrfs_btree_balance_dirty(root, nr);
3832 if (err) {
3833 if (inode)
3834 iput(inode);
3835 inode = ERR_PTR(err);
3836 }
3837 return inode;
3838 }
3839
3840 static struct reloc_control *alloc_reloc_control(void)
3841 {
3842 struct reloc_control *rc;
3843
3844 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3845 if (!rc)
3846 return NULL;
3847
3848 INIT_LIST_HEAD(&rc->reloc_roots);
3849 backref_cache_init(&rc->backref_cache);
3850 mapping_tree_init(&rc->reloc_root_tree);
3851 extent_io_tree_init(&rc->processed_blocks, NULL, GFP_NOFS);
3852 return rc;
3853 }
3854
3855 /*
3856 * function to relocate all extents in a block group.
3857 */
3858 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
3859 {
3860 struct btrfs_fs_info *fs_info = extent_root->fs_info;
3861 struct reloc_control *rc;
3862 int ret;
3863 int rw = 0;
3864 int err = 0;
3865
3866 rc = alloc_reloc_control();
3867 if (!rc)
3868 return -ENOMEM;
3869
3870 rc->extent_root = extent_root;
3871
3872 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
3873 BUG_ON(!rc->block_group);
3874
3875 if (!rc->block_group->ro) {
3876 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
3877 if (ret) {
3878 err = ret;
3879 goto out;
3880 }
3881 rw = 1;
3882 }
3883
3884 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
3885 if (IS_ERR(rc->data_inode)) {
3886 err = PTR_ERR(rc->data_inode);
3887 rc->data_inode = NULL;
3888 goto out;
3889 }
3890
3891 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
3892 (unsigned long long)rc->block_group->key.objectid,
3893 (unsigned long long)rc->block_group->flags);
3894
3895 btrfs_start_delalloc_inodes(fs_info->tree_root, 0);
3896 btrfs_wait_ordered_extents(fs_info->tree_root, 0, 0);
3897
3898 while (1) {
3899 mutex_lock(&fs_info->cleaner_mutex);
3900
3901 btrfs_clean_old_snapshots(fs_info->tree_root);
3902 ret = relocate_block_group(rc);
3903
3904 mutex_unlock(&fs_info->cleaner_mutex);
3905 if (ret < 0) {
3906 err = ret;
3907 goto out;
3908 }
3909
3910 if (rc->extents_found == 0)
3911 break;
3912
3913 printk(KERN_INFO "btrfs: found %llu extents\n",
3914 (unsigned long long)rc->extents_found);
3915
3916 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
3917 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
3918 invalidate_mapping_pages(rc->data_inode->i_mapping,
3919 0, -1);
3920 rc->stage = UPDATE_DATA_PTRS;
3921 }
3922 }
3923
3924 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
3925 rc->block_group->key.objectid,
3926 rc->block_group->key.objectid +
3927 rc->block_group->key.offset - 1);
3928
3929 WARN_ON(rc->block_group->pinned > 0);
3930 WARN_ON(rc->block_group->reserved > 0);
3931 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
3932 out:
3933 if (err && rw)
3934 btrfs_set_block_group_rw(extent_root, rc->block_group);
3935 iput(rc->data_inode);
3936 btrfs_put_block_group(rc->block_group);
3937 kfree(rc);
3938 return err;
3939 }
3940
3941 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
3942 {
3943 struct btrfs_trans_handle *trans;
3944 int ret;
3945
3946 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
3947
3948 memset(&root->root_item.drop_progress, 0,
3949 sizeof(root->root_item.drop_progress));
3950 root->root_item.drop_level = 0;
3951 btrfs_set_root_refs(&root->root_item, 0);
3952 ret = btrfs_update_root(trans, root->fs_info->tree_root,
3953 &root->root_key, &root->root_item);
3954 BUG_ON(ret);
3955
3956 ret = btrfs_end_transaction(trans, root->fs_info->tree_root);
3957 BUG_ON(ret);
3958 return 0;
3959 }
3960
3961 /*
3962 * recover relocation interrupted by system crash.
3963 *
3964 * this function resumes merging reloc trees with corresponding fs trees.
3965 * this is important for keeping the sharing of tree blocks
3966 */
3967 int btrfs_recover_relocation(struct btrfs_root *root)
3968 {
3969 LIST_HEAD(reloc_roots);
3970 struct btrfs_key key;
3971 struct btrfs_root *fs_root;
3972 struct btrfs_root *reloc_root;
3973 struct btrfs_path *path;
3974 struct extent_buffer *leaf;
3975 struct reloc_control *rc = NULL;
3976 struct btrfs_trans_handle *trans;
3977 int ret;
3978 int err = 0;
3979
3980 path = btrfs_alloc_path();
3981 if (!path)
3982 return -ENOMEM;
3983
3984 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
3985 key.type = BTRFS_ROOT_ITEM_KEY;
3986 key.offset = (u64)-1;
3987
3988 while (1) {
3989 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
3990 path, 0, 0);
3991 if (ret < 0) {
3992 err = ret;
3993 goto out;
3994 }
3995 if (ret > 0) {
3996 if (path->slots[0] == 0)
3997 break;
3998 path->slots[0]--;
3999 }
4000 leaf = path->nodes[0];
4001 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4002 btrfs_release_path(root->fs_info->tree_root, path);
4003
4004 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4005 key.type != BTRFS_ROOT_ITEM_KEY)
4006 break;
4007
4008 reloc_root = btrfs_read_fs_root_no_radix(root, &key);
4009 if (IS_ERR(reloc_root)) {
4010 err = PTR_ERR(reloc_root);
4011 goto out;
4012 }
4013
4014 list_add(&reloc_root->root_list, &reloc_roots);
4015
4016 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4017 fs_root = read_fs_root(root->fs_info,
4018 reloc_root->root_key.offset);
4019 if (IS_ERR(fs_root)) {
4020 ret = PTR_ERR(fs_root);
4021 if (ret != -ENOENT) {
4022 err = ret;
4023 goto out;
4024 }
4025 mark_garbage_root(reloc_root);
4026 }
4027 }
4028
4029 if (key.offset == 0)
4030 break;
4031
4032 key.offset--;
4033 }
4034 btrfs_release_path(root->fs_info->tree_root, path);
4035
4036 if (list_empty(&reloc_roots))
4037 goto out;
4038
4039 rc = alloc_reloc_control();
4040 if (!rc) {
4041 err = -ENOMEM;
4042 goto out;
4043 }
4044
4045 rc->extent_root = root->fs_info->extent_root;
4046
4047 set_reloc_control(rc);
4048
4049 trans = btrfs_join_transaction(rc->extent_root, 1);
4050
4051 rc->merge_reloc_tree = 1;
4052
4053 while (!list_empty(&reloc_roots)) {
4054 reloc_root = list_entry(reloc_roots.next,
4055 struct btrfs_root, root_list);
4056 list_del(&reloc_root->root_list);
4057
4058 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4059 list_add_tail(&reloc_root->root_list,
4060 &rc->reloc_roots);
4061 continue;
4062 }
4063
4064 fs_root = read_fs_root(root->fs_info,
4065 reloc_root->root_key.offset);
4066 BUG_ON(IS_ERR(fs_root));
4067
4068 __add_reloc_root(reloc_root);
4069 fs_root->reloc_root = reloc_root;
4070 }
4071
4072 btrfs_commit_transaction(trans, rc->extent_root);
4073
4074 merge_reloc_roots(rc);
4075
4076 unset_reloc_control(rc);
4077
4078 trans = btrfs_join_transaction(rc->extent_root, 1);
4079 btrfs_commit_transaction(trans, rc->extent_root);
4080 out:
4081 kfree(rc);
4082 while (!list_empty(&reloc_roots)) {
4083 reloc_root = list_entry(reloc_roots.next,
4084 struct btrfs_root, root_list);
4085 list_del(&reloc_root->root_list);
4086 free_extent_buffer(reloc_root->node);
4087 free_extent_buffer(reloc_root->commit_root);
4088 kfree(reloc_root);
4089 }
4090 btrfs_free_path(path);
4091
4092 if (err == 0) {
4093 /* cleanup orphan inode in data relocation tree */
4094 fs_root = read_fs_root(root->fs_info,
4095 BTRFS_DATA_RELOC_TREE_OBJECTID);
4096 if (IS_ERR(fs_root))
4097 err = PTR_ERR(fs_root);
4098 else
4099 btrfs_orphan_cleanup(fs_root);
4100 }
4101 return err;
4102 }
4103
4104 /*
4105 * helper to add ordered checksum for data relocation.
4106 *
4107 * cloning checksum properly handles the nodatasum extents.
4108 * it also saves CPU time to re-calculate the checksum.
4109 */
4110 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4111 {
4112 struct btrfs_ordered_sum *sums;
4113 struct btrfs_sector_sum *sector_sum;
4114 struct btrfs_ordered_extent *ordered;
4115 struct btrfs_root *root = BTRFS_I(inode)->root;
4116 size_t offset;
4117 int ret;
4118 u64 disk_bytenr;
4119 LIST_HEAD(list);
4120
4121 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4122 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4123
4124 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4125 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4126 disk_bytenr + len - 1, &list);
4127
4128 while (!list_empty(&list)) {
4129 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4130 list_del_init(&sums->list);
4131
4132 sector_sum = sums->sums;
4133 sums->bytenr = ordered->start;
4134
4135 offset = 0;
4136 while (offset < sums->len) {
4137 sector_sum->bytenr += ordered->start - disk_bytenr;
4138 sector_sum++;
4139 offset += root->sectorsize;
4140 }
4141
4142 btrfs_add_ordered_sum(inode, ordered, sums);
4143 }
4144 btrfs_put_ordered_extent(ordered);
4145 return 0;
4146 }
4147
4148 void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4149 struct btrfs_root *root, struct extent_buffer *buf,
4150 struct extent_buffer *cow)
4151 {
4152 struct reloc_control *rc;
4153 struct backref_node *node;
4154 int first_cow = 0;
4155 int level;
4156 int ret;
4157
4158 rc = root->fs_info->reloc_ctl;
4159 if (!rc)
4160 return;
4161
4162 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4163 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4164
4165 level = btrfs_header_level(buf);
4166 if (btrfs_header_generation(buf) <=
4167 btrfs_root_last_snapshot(&root->root_item))
4168 first_cow = 1;
4169
4170 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4171 rc->create_reloc_tree) {
4172 WARN_ON(!first_cow && level == 0);
4173
4174 node = rc->backref_cache.path[level];
4175 BUG_ON(node->bytenr != buf->start &&
4176 node->new_bytenr != buf->start);
4177
4178 drop_node_buffer(node);
4179 extent_buffer_get(cow);
4180 node->eb = cow;
4181 node->new_bytenr = cow->start;
4182
4183 if (!node->pending) {
4184 list_move_tail(&node->list,
4185 &rc->backref_cache.pending[level]);
4186 node->pending = 1;
4187 }
4188
4189 if (first_cow)
4190 __mark_block_processed(rc, node);
4191
4192 if (first_cow && level > 0)
4193 rc->nodes_relocated += buf->len;
4194 }
4195
4196 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) {
4197 ret = replace_file_extents(trans, rc, root, cow);
4198 BUG_ON(ret);
4199 }
4200 }
4201
4202 /*
4203 * called before creating snapshot. it calculates metadata reservation
4204 * requried for relocating tree blocks in the snapshot
4205 */
4206 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4207 struct btrfs_pending_snapshot *pending,
4208 u64 *bytes_to_reserve)
4209 {
4210 struct btrfs_root *root;
4211 struct reloc_control *rc;
4212
4213 root = pending->root;
4214 if (!root->reloc_root)
4215 return;
4216
4217 rc = root->fs_info->reloc_ctl;
4218 if (!rc->merge_reloc_tree)
4219 return;
4220
4221 root = root->reloc_root;
4222 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4223 /*
4224 * relocation is in the stage of merging trees. the space
4225 * used by merging a reloc tree is twice the size of
4226 * relocated tree nodes in the worst case. half for cowing
4227 * the reloc tree, half for cowing the fs tree. the space
4228 * used by cowing the reloc tree will be freed after the
4229 * tree is dropped. if we create snapshot, cowing the fs
4230 * tree may use more space than it frees. so we need
4231 * reserve extra space.
4232 */
4233 *bytes_to_reserve += rc->nodes_relocated;
4234 }
4235
4236 /*
4237 * called after snapshot is created. migrate block reservation
4238 * and create reloc root for the newly created snapshot
4239 */
4240 void btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4241 struct btrfs_pending_snapshot *pending)
4242 {
4243 struct btrfs_root *root = pending->root;
4244 struct btrfs_root *reloc_root;
4245 struct btrfs_root *new_root;
4246 struct reloc_control *rc;
4247 int ret;
4248
4249 if (!root->reloc_root)
4250 return;
4251
4252 rc = root->fs_info->reloc_ctl;
4253 rc->merging_rsv_size += rc->nodes_relocated;
4254
4255 if (rc->merge_reloc_tree) {
4256 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4257 rc->block_rsv,
4258 rc->nodes_relocated);
4259 BUG_ON(ret);
4260 }
4261
4262 new_root = pending->snap;
4263 reloc_root = create_reloc_root(trans, root->reloc_root,
4264 new_root->root_key.objectid);
4265
4266 __add_reloc_root(reloc_root);
4267 new_root->reloc_root = reloc_root;
4268
4269 if (rc->create_reloc_tree) {
4270 ret = clone_backref_node(trans, rc, root, reloc_root);
4271 BUG_ON(ret);
4272 }
4273 }
Linux with added FPC-III support